Recipient Health Dictionary

Recipient: From 1 Different Sources


Bone Marrow Transplant

The procedure by which malignant or defective bone marrow in a patient is replaced with normal bone marrow. Sometimes the patient’s own marrow is used (when the disease is in remission); after storage using tissue-freezing technique (cryopreservation) it is reinfused into the patient once the diseased marrow has been treated (autologous transplant). More commonly, a transplant uses marrow from a donor whose tissue has been matched for compatibility. The recipient’s marrow is destroyed with CYTOTOXIC drugs before transfusion. The recipient is initially nursed in an isolated environment to reduce the risk of infection.

Disorders that can be helped or even cured include certain types of LEUKAEMIA and many inherited disorders of the immune system (see IMMUNITY).... bone marrow transplant

Pedicle

A narrow tube of tissue formed by folded skin which links a piece of tissue used for surgical grafting to its site of origin. A pedicle graft is used by the surgeon – usually a reconstructive/ plastic surgeon – when the site under repair is unsuitable for an independent graft, usually because the blood supply at the recipient site is inadequate. (See RECONSTRUCTIVE (PLASTIC) SURGERY.)

A pedicle is also found occurring between a tumour and its tissue of origin, and the term is used in anatomy to refer to any slim tubular process.... pedicle

Transfusion

The administration of any ?uid into a person’s vein using a drip. This apparatus facilitates a continuous injection in which the ?uid ?ows by force of gravity from a suspended bottle, via a tube that is ?xed to a hollow needle inserted into a vein (usually in the front of the elbow). Saline solution, PLASMA and whole BLOOD (see below) are the most commonly administered ?uids. Saline is used to restore ?uid to a seriously dehydrated individual (see DEHYDRATION) and may be used as a temporary measure in SHOCK due to blood loss while the appropriate type of blood is being obtained for transfusion. Saline may also be useful as a way of administering a regular supply of a drug over a period of time. Plasma is normally used as a temporary measure in the treatment of shock until appropriately matched blood is available or if for any reason, such as for a patient with severe burns, plasma is preferable to blood.

Transfusion of blood is a technique that has been used since the 17th century – although, until the 20th century, with a subsequent high mortality rate. It was only when incompatibility of BLOOD GROUPS was considered as a potential cause of this high mortality that routine blood-testing became standard practice. Since the National Blood Transfusion Service was started in the United Kingdom (in 1946), blood for transfusion has been collected from voluntary, unpaid donors: this is screened for infections such as SYPHILIS, HIV, HEPATITIS and nvCJD (see CREUTZFELDT-JAKOB DISEASE (CJD)), sorted by group, and stored in blood-banks throughout the country.

In the UK in 2004, the National Blood Authority – today’s transfusion service – announced that it would no longer accept donations from anyone who had received a blood transfusion since 1980 – because of the remote possibility that they might have been infected with the PRION which causes nvCJD.

A standard transfusion bottle has been developed, and whole blood may be stored at 2–6 °C for three weeks before use. Transfusions may then be given of whole blood, plasma, blood cells, or PLATELETS, as appropriate. Stored in the dried form at 4–21 °C, away from direct sunlight, human plasma is stable for ?ve years and is easily reconstituted by adding sterile distilled water.

The National Blood Authority prepares several components from each donated unit of blood: whole blood is rarely used in adults. This permits each product, whether plasma or various red-cell concentrates, to be stored under ideal conditions and used in appropriate clinical circumstances – say, to restore blood loss or to treat haemostatic disorders.

Transfusion of blood products can cause complications. Around 5 per cent of transfused patients suffer from a reaction; most are mild, but they can be severe and occasionally fatal. It can be di?cult to distinguish a transfusion reaction from symptoms of the condition being treated, but the safe course is to stop the transfusion and start appropriate investigation.

In the developed world, clinicians can expect to have access to high-quality blood products, with the responsibility of providing blood resting with a specially organised transfusion service. The cause of most fatal haemolytic transfusion reactions is a clerical error due to faulty labelling and/or failure to identify the recipient correctly. Hospitals should have a strict protocol to prevent such errors.

Arti?cial blood Transfusion with blood from donors is facing increasing problems. Demand is rising; suitable blood donors are becoming harder to attract; the processes of taking, storing and cross-matching donor blood are time-consuming and expensive; the shelf-life is six weeks; and the risk of adverse reactions or infection from transfused blood, although small, is always present. Arti?cial blood would largely overcome these drawbacks. Several companies in North America are now preparing this: one product uses puri?ed HAEMOGLOBIN from humans and another from cows. These provide oxygen-carrying capacity, are unlikely to be infectious and do not provoke immunological rejections. Yet another product, called Oxygene®, does not contain any animal or human blood products; it comprises salt water and a substance called per?ubron, the molecules of which store oxygen and absorb carbon dioxide more e?ectively than does haemoglobin. Within 24 hours of being transfused into a person’s bloodstream, per?ubron evaporates and is harmlessly breathed out by the recipient. Arti?cial blood is especially valuable in that it contains no unwanted proteins that can provoke adverse immunological reactions. Furthermore, it is disease-free, lasts for up to three years and is no more expensive than donor blood. It could well take the place of donor blood within a few years.

Autologous transfusion is the use of an individual’s own blood, provided in advance, for transfusion during or after a surgical operation. This is a valuable procedure for operations that may require large transfusions or where a person has a rare blood group. Its use has increased for several reasons:

fear of infection such as HIV and hepatitis.

shortages of donor blood and the rising cost of units of blood.

substantial reduction of risk of incompatible transfusions. In practice, blood transfusion in the UK is

remarkably safe, but there is always room for improvement. So, in the 1990s, a UK inquiry on the Serious Hazards of Transfusion (SHOT) was launched. It established (1998) that of 169 recently reported serious hazards following blood transfusion, 81 had involved a blood component being given to the wrong patient, while only eight were the result of viral or bacterial infections.

There are three ways to use a patient’s own blood in transfusion:

(1) predeposit autologous donation (PAD) – taking blood from a patient before operation and transfusing this blood back into the patient as required during and after operation.

(2) acute normovalaemic haemodilution (ANH) – diluting previously withdrawn blood and thus increasing the volume before transfusion.

(3) perioperative cell salvage (PCS) – the use of centrifugal cell separation on blood saved during an operation, particularly spinal surgery where blood loss may be considerable.

The government has urged NHS trusts to consider the introduction of PCS as a possible adjunct or alternative to banked-blood transfusion. In one centre (Nottingham), PCS has been used in the form of continuous autologous transfusion for several years with success.

Exchange transfusion is the method of treatment in severe cases of HAEMOLYTIC DISEASE OF THE NEWBORN. It consists of replacing the whole of the baby’s blood with Rh-negative blood of the correct blood group for the baby.... transfusion

Transplantation

Transplantation of tissues or organs of the body are de?ned as an allotransplant, if from another person; an autotransplant, if from the patient him or herself – for example, a skin graft (see GRAFT; SKIN-GRAFTING); and a xenotransplant, if from an animal.

The pioneering success was achieved with transplantation of the kidney in the 1970s; this has been most successful when the transplanted kidney has come from an identical twin. Less successful have been live transplants from other blood relatives, while least successful have been transplants from other live donors and cadaver donors. The results, however, are steadily improving. Thus the one-year functional survival of kidneys transplanted from unrelated dead donors has risen from around 50 per cent to over 80 per cent, and survival rates of 80 per cent after three years are not uncommon. For a well-matched transplant from a live related donor, the survival rate after ?ve years is around 90 per cent. And, of course, if a transplanted kidney fails to function, the patient can always be switched on to some form of DIALYSIS. In the United Kingdom the supply of cadaveric (dead) kidneys for transplantation is only about half that necessary to meet the demand.

Other organs that have been transplanted with increasing success are the heart, the lungs, the liver, bone marrow, and the cornea of the eye. Heart, lung, liver and pancreas transplantations are now carried out in specialist centres. It is estimated that in the United Kingdom, approximately 200 patients a year between the ages of 15 and 55 would bene?t from a liver transplant if an adequate number of donors were available. More than 100 liver transplants are carried out annually in the United Kingdom and one-year-survival rates of up to 80 per cent have been achieved.

The major outstanding problem is how to prevent the recipient’s body from rejecting and destroying the transplanted organ. Such rejection is part of the normal protective mechanism of the body (see IMMUNITY). Good progress has been made in techniques of tissue-typing and immunosuppression to overcome the problem. Drugs are now available that can suppress the immune reactions of the recipient, which are responsible for the rejection of the transplanted organ. Notable among these are CICLOSPORIN A, which revolutionised the success rate, and TACROLIMUS, a macrolide immunosuppressant.

Another promising development is antilymphocytic serum (ALS), which reduces the activity of the lymphocytes (see LYMPHOCYTE) cells which play an important part in maintaining the integrity of the body against foreign bodies.

Donor cards are now available in all general practitioners’ surgeries and pharmacies but, of the millions of cards distributed since 1972, too few have been used. The reasons are complex but include the reluctance of the public and doctors to consider organ donation; poor organisation for recovery of donor kidneys; and worries about the diagnosis of death. A code of practice for procedures relating to the removal of organs for transplantation was produced in 1978, and this code has been revised in the light of further views expressed by the Conference of Medical Royal Colleges and Faculties of the United Kingdom on the Diagnosis of Brain Death. Under the Human Tissue Act 1961, only the person lawfully in possession of the body or his or her designate can authorise the removal of organs from a body. This authorisation may be given orally.

Patients who may become suitable donors after death are those who have suffered severe and irreversible brain damage – since such patients will be dependent upon arti?cial ventilation. Patients with malignant disease or systemic infection, and patients with renal disease, including chronic hypertension, are unsuitable.

If a patient carries a signed donor card or has otherwise recorded his or her wishes, there is no legal requirement to establish lack of objection on the part of relatives – although it is good practice to take account of the views of close relatives. If a relative objects, despite the known request by the patient, sta? will need to judge, according to the circumstances of the case, whether it is wise to proceed with organ removal. If a patient who has died is not known to have requested that his or her organs be removed for transplantation after death, the designated person may only authorise the removal if, having made such reasonable enquiry as may be practical, he or she has no reason to believe (a) that the deceased had expressed an objection to his or her body being so dealt with after death, or (b) that the surviving spouse or any surviving relative of the deceased objects to the body being so dealt with. Sta? will need to decide who is best quali?ed to approach the relatives. This should be someone with appropriate experience who is aware how much the relative already knows about the patient’s condition. Relatives should not normally be approached before death has occurred, but sometimes a relative approaches the hospital sta? and suggests some time in advance that the patient’s organs might be used for transplantation after death. The sta? of hospitals and organ exchange organisations must respect the wishes of the donor, the recipient and their families with respect to anonymity.

Relatives who enquire should be told that some post-mortem treatment of the donor’s body will be necessary if the organs are to be removed in good condition. It is ethical (see ETHICS) to maintain arti?cial ventilation and heartbeat until removal of organs has been completed. This is essential in the case of heart and liver transplants, and many doctors think it is desirable when removing kidneys. O?cial criteria have been issued in Britain to recognise when BRAIN-STEM DEATH has occurred. This is an important protection for patients and relatives when someone with a terminal condition

– usually as a result of an accident – is considered as a possible organ donor.... transplantation

Cloning

Cloning – from the Greek klon, meaning a cutting such as is used to propagate plants – is essentially a form of asexual reproduction. The initial stages were ?rst successfully achieved in rabbits. In essence the technique consists of destroying the nucleus of the egg and replacing it with the nucleus from a body cell of the same species – either a male or a female. This provides the egg with a full complement of CHROMOSOMES and it starts to divide and grow just as it would if it had retained its nucleus and been fertilised with a spermatozoon. The vital di?erence is that the embryo resulting from this cloning process owes nothing genetically to the female egg. It is identical in every respect with the animal from which the introduced nucleus was obtained.

In 1997 the ?rst mammal to be cloned from the tissue of an adult animal was born. A technique that scientists have been trying to perfect for decades, the success of the Roslin Institute, near Edinburgh, in producing ‘Dolly’, a cloned sheep, has profound implications. Already some scientists are talking of cloning humans, although this has great medical, legal and ethical consequences. The key to the scientists’ success in producing Dolly was the ability to coordinate the fusion of a donor cell (from an adult) containing all its DNA with a recipient egg from which DNA had been removed. The di?culty of the technique is shown by the fact that, out of 277 fused pairs of cells where the donor cell was from adult tissue, Dolly was the only survivor and she has developed premature arthritis. Research suggests that cloning may be accompanied by a higher than normal incidence of congenital defects.

Since Dolly was born, other animal clones have been produced and American researchers have cloned the ?rst human embryo – which grew to six cells – with the aim of providing stem cells for therapeutic use. As a result the UK government passed emergency legislation to outlaw human cloning for reproductive purposes.... cloning

Corneal Graft

Also known as keratoplasty. If the cornea (see EYE) becomes damaged or diseased and vision is impaired, it can be removed and replaced by a corneal graft. The graft is taken from the cornea of a human donor. Some of the indications for corneal grafting include keratoconus (conicalshaped cornea), corneal dystrophies, severe corneal scarring following HERPES SIMPLEX, and alkali burns or other injury. Because the graft is a foreign protein, there is a danger that the recipient’s immune system may set up a reaction causing rejection of the graft. Rejection results in OEDEMA of the graft with subsequent poor vision. Once a corneal graft has been taken from a donor, it should be used as quickly as possible. Corneas can be stored for days in tissue-culture medium at low temperature. A small number of grafts are autografts in which a patient’s cornea is repositioned.

The Department of Health has drawn up a list of suitable eye-banks to which people can apply to bequeath their eyes, and an o?cial form is now available for the bequest of eyes. (See also DONORS; TRANSPLANTATION.)... corneal graft

Cystic Fibrosis

This is the most common serious genetic disease in Caucasian children, with an incidence of about one per 2,500 births, and more than 6,000 patients in the UK (30,000 in the USA). It is an autosomal recessive disorder of the mucus-secreting glands of the lungs, the pancreas, the mouth, and the gastrointestinal tract, as well as the sweat glands of the skin. The defective gene is sited on chromosome 7 which encodes for a protein, cystic ?brosis transmembrane conductance regulator (CFTR). Individuals who inherit the gene only on one set of chromosomes can, however, carry the defect into successive generations. Where parents have a child with cystic ?brosis, they have a one-infour chance of subsequent children having the disease. They should seek GENETIC COUNSELLING.

The disorder is characterised by failure to gain weight in spite of a good appetite, by repeated attacks of bronchitis (with BRONCHIECTASIS developing at a young age), and by the passage of loose, foul-smelling and slimy stools (faeces). AMNIOCENTESIS, which yields amniotic ?uid along with cells shed from the fetus’s skin, can be used to diagnose cystic ?brosis prenatally. The levels of various enzymes can be measured in the ?uid and are abnormal when the fetus is affected by cystic ?brosis. Neonatal screening is possible using a test on blood spots – immunoreactive trypsin (IRT).

In children with symptoms or a positive family history, the disease can be tested for by measuring sweat chloride and sodium. This detects the abnormal amount of salt that is excreted via the sweat glands when cystic ?brosis is present. Con?rmation is by genetic testing.

Treatment This consists basically of regular physiotherapy and postural drainage, antibiotics and the taking of pancreatic enzyme tablets and vitamins. Some children need STEROID treatment and all require nutritional support. The earlier treatment is started, the better the results. Whereas two decades ago, only 12 per cent of affected children survived beyond adolescence, today 75 per cent survive into adult life, and an increasing number are surviving into their 40s. Patients with end-stage disease can be treated by heart-lung transplantation (with their own heart going to another recipient). Research is underway on the possible use of GENE THERAPY to control the disorder. Parents of children with cystic ?brosis, seeking help and advice, can obtain this from the Cystic Fibrosis Trust.... cystic fibrosis

Graft Versus Host Disease (gvhd)

A condition that is a common complication of BONE MARROW transplant (see TRANSPLANTATION). It results from certain LYMPHOCYTES in the transplanted marrow attacking the transplant recipient’s tissues, which they identify as ‘foreign’. GVHD may appear soon after a transplant or develop several months later. The condition, which is fatal in about a third of victims, may be prevented by immunosuppressant drugs such as ciclosporin.... graft versus host disease (gvhd)

Community Care

Community care is intended to enable people to lead independent lives at home or in local residential units for as long as they are able to do so. For many years there has been a trend in Britain for care of elderly people and those with mental or physical problems to be shifted from hospitals and into community settings. In 1988 Sir Roy Gri?ths’s report to the Secretaries of State for Social Services, Community Care: Agenda for Action, advised on the best use of public funds to provide e?ective community care. The White Paper Caring for People, published in 1989, outlined the government’s ideas for developing these proposals further. The plans were then enshrined in law with the National Health Service and Community Care Act of 1990.

Since April 1993, local social-services departments have been responsible for assessing what help people need from community-care services: these can include home helps, meals on wheels, sheltered housing, etc. Recipients of such services are means-tested and make variable contributions towards the costs. Policies on charging vary from one area to another and there are wide geographical variations in the range of services provided free and the charges levied for others.

People with complex needs may be assigned a case manager to coordinate the care package and ensure that appropriate responses are made to changing circumstances. The success of community care hinges on e?ective coordination of the services of an often large number of providers from the health and social-services sectors. Poor communication between sectors and inadequate coordination of services have been among the most common complaints about the community-care reforms.

Health care for people being cared for in the community remains largely free under the NHS arrangements, although there are regular debates about where the boundaries should be drawn between free health services and means-tested social care. A distinction has been made between necessary nursing care (funded by the state) and normal personal care (the responsibility of the patient), but the dividing line often proves hard to de?ne.

As care has shifted increasingly into the community, previous hospital facilities have become redundant. Vast numbers of beds in long-stay geriatric hospitals and in-patient psychiatric wards have been closed. There is now concern that too few beds remain to provide essential emergency and respite services. In some areas, patients ?t for discharge are kept in hospital because of delay in setting up community services for the elderly, or because of the inability of the local authority to fund appropriate care in a nursing home or at home with community-care support for other patients; the resulting BED-BLOCKING has an adverse e?ect on acutely ill patients needing hospital admission.

Community care, if correctly funded and coordinated, is an excellent way of caring for people with long-term needs, but considerable work is still needed in Britain to ensure that all patients have access to high-quality community care when they need it. Problems in providing such are are not con?ned to the UK.... community care

Donors

People who donate parts of their bodies for use in other people. Many organs and tissues can be donated – most commonly blood, but skin, corneas, kidneys, livers and hearts can all be used. Combined heart and lung transplants are being increasingly used for patients with severe lung diseases, and, if the recipients have a condition such as CYSTIC FIBROSIS in which the heart is normal, it is sometimes possible for them to receive a heart and lungs from one donor and to donate their own heart to someone else. Recent work has explored the possibility of using pancreatic transplants. Apart from blood, it is unusual for tissue to be taken from living donors. Skin, small pieces of liver, and a kidney can, in theory, be obtained from living donors, but the ETHICS of this are hotly debated and the situations under which it may be done are tightly controlled. Because transplanted organs are seen by the receiving body as ‘foreign bodies’, careful matching before transplantation is necessary to avoid rejection, and immunosuppressive drugs may be required for some time after the operation to prevent this from occurring.

There are strict regulations about how death should be diagnosed before organs can be removed for transplantation, and potential donors must satisfy the BRAIN-STEM DEATH criteria, performed twice by two doctors who are independent of the transplant team. There is a great shortage of suitable organs for donation – partly because they must be in excellent condition if the operation is to be a success. Some medical conditions or modes of death make people unsuitable as organ donors; this makes it all the more important that people should be encouraged to donate their organs. People who wish to do so can carry a special card indicating their willingness to become donors in the event of their death. These cards can be obtained from various sources, including hospitals, GPs’ surgeries and many public buildings such as libraries. In the UK, informed positive approval from the patient, or relatives, is required.

Information about becoming a blood donor can be obtained by telephoning 0845–7 711

711. Those who wish to bequeath their bodies for dissection purposes should get in touch with HM Inspector of Anatomy. Other would-be organ donors may contact the British Organ Donor Society.... donors

Health Team

A group of persons working together, where each member of the team contributes, in accordance with his or her competence and skill and in coordination with the functions of the others, in order to achieve the maximum benefit for the care recipient.... health team

Heart-lung Transplant

An operation in which a patient’s diseased lungs and heart are removed and replaced with donor organs from someone who has been certi?ed as ‘brain dead’ (see BRAIN-STEM DEATH). As well as the technical diffculties of such an operation, rejection by the recipient’s tissues of donated heart and lungs has proved hard to overcome. Since the early 1990s, however, immunosuppressant drug therapy (see CICLOSPORIN; TRANSPLANTATION) has facilitated the regular use of this type of surgery. Even so, patients receiving transplanted hearts and lungs face substantial risks such as lung infection and airway obstruction as well as the long-term problems of transplant rejection.... heart-lung transplant

Incompatibility

(1) In the pharmacological context, the use of two or more drugs in treatment which together produce adverse consequences for the patient. The British National Formulary carries an appendix devoted to drug interactions.

(2) In the haematological context, an adverse reaction in a patient given a blood TRANSFUSION in which the donor blood is incompatible with that of the recipient.... incompatibility

Growth Hormone

A product of the anterior part of the PITUITARY GLAND that promotes normal growth and development in the body by changing the chemical activity in the cells. The hormone activates protein production in the muscle cells as well as the release of energy from the metabolism of fats. Its release is controlled by the contrasting actions of growth-hormone releasing factor and somatostatin. If the body produces too much growth hormone before puberty GIGANTISM results; in adulthood the result is ACROMEGALY. Lack of growth hormone in children retards growth.

For many years growth hormone was extracted from human corpses and very rarely this caused CREUTZFELDT-JAKOB DISEASE (CJD) in the recipients. The hormone is now genetically engineered, so safe.... growth hormone

Heart Surgery

Open-heart surgery permits the treatment of many previously inoperable conditions that were potentially fatal, or which made the patient chronically disabled. CORONARY ARTERY VEIN BYPASS GRAFTING (CAVBG), used to remedy obstruction of the arteries supplying the heart muscle, was ?rst carried out in the mid1960s and is now widely practised. Constricted heart valves today are routinely dilated by techniques of MINIMALLY INVASIVE SURGERY (MIS), such as ANGIOPLASTY and laser treatment, and faulty valves can be replaced with mechanical alternatives (see VALVULOPLASTY).

Heart transplant Replacement of a person’s unhealthy heart with a normal heart from a healthy donor. The donor’s heart needs to be removed immediately after death and kept chilled in saline before rapid transport to the recipient. Heart transplants are technically demanding operations used to treat patients with progressive untreatable heart disease but whose other body systems are in good shape. They usually have advanced coronary artery disease and damaged heart muscle (CARDIOMYOPATHY). Apart from the technical diffculties of the operation, preventing rejection of the transplanted heart by the recipient’s immune system requires complex drug treatment. But once the patient has passed the immediate postoperative phase, the chances of ?ve-year survival is as high as 80 per cent in some cardiac centres. A key di?culty in doing heart transplants is a serious shortage of donor organs.... heart surgery

Medical Negligence

Under the strict legal de?nition, negligence must involve proving a clearly established duty of care which has been breached in a way that has resulted in injury or harm to the recipient of care. There does not need to be any malicious intention. Whether or not a particular injury can be attributed to medical negligence, or must simply be accepted as a reasonable risk of the particular treatment, depends upon an assessment of whether the doctor has fallen below the standard expected of practitioners in the particular specialty. A defence to such a claim is that a respected body of practitioners would have acted in the same way (even though the majority might not) and in doing so would have acted logically.... medical negligence

Predictive Value

1 The statistic generated by dividing the number of true positives by the sum of the true positives and false positives. For example, the number of cases with truly good care divided by the sum of the cases with truly good care plus those cases classified with good care who did not receive it i.e. the likelihood that a person classified as the recipient of good care actually received good care. 2 In screening and diagnostic tests, the probability that a person with a positive test result is a true positive (i.e. does have the disease) is referred to as the “predictive value of a positive test”. The predictive value of a negative test is the probability that a person with a negative test does not have the condition or disease. The predictive value of a screening test is determined by the sensitivity and specificity of the test, and by the prevalence of the condition for which the test is used.... predictive value

Resident

The recipient of care in a residential care facility.... resident

Resident Classification Instrument

An instrument which assesses recipient’s care needs. It has a number of classification levels, ranging from high to low care. These classification levels are sometimes used for placement, staffing level and reimbursement purposes.... resident classification instrument

Salk Vaccine

A vaccine obtained by treating the POLIOMYELITIS virus with formalin. This prevents the virus from causing the disease but allows it to stimulate the production of ANTIBODIES. Salk vaccine is given by injection and protects the recipient against the disease. (See also IMMUNISATION.)... salk vaccine

Sensitivity

A high rate of detection of “true positives”, for example, the fraction of subjects who actually received good care who are classified as recipients of good care. For medical screening tests, sensitivity is the proportion of truly diseased persons in the screened population who are identified as diseased by the screening test. Sensitivity is a measure of the probability of correctly diagnosing a case, or the probability that any given case will be identified by the test (synonymous with ‘true positive rate’).... sensitivity

Small-bowel Transplantantion

Before the advent of small-bowel transplants, long-term intravenous feeding (total parenteral nutrition or TPN) was the last option for patients with chronic intestinal failure. Most recipients are children, and small-bowel transplantation is currently reserved for patients unable to continue on long-term parenteral nutrition. The main constraints to small-bowel transplantation are the intensity of rejection (necessitating high levels of immunosuppression), and the lack of donors who are the same size as the recipient (a particular problem for children).... small-bowel transplantantion

Specificity

A high rate of detection of “true negatives”, for example, the fraction of subjects who actually received bad care who are classified as recipients of bad care. For medical screening tests, the proportion of truly non-diseased persons who are so identified by the screening test. It is a measure of the probability of correctly identifying a non-diseased person with a screening test (synonymous with ‘true negative rate’).... specificity

Medical Education

This term is used to de?ne the process of learning and knowledge-acquisition in the study of medicine. It also encompasses the expertise required to develop education and training for students and learners in all aspects of medical health care. Studies for undergraduate students, postgraduate students and individual health-care practitioners, from the initial stages to the ongoing development of a career in medicine or associated health ?elds, are also included in medical education. The word ‘pedagogy’ is sometimes applied to this process.

A range of research investigations has developed within medical education. These apply to course monitoring, audit, development and validation, assessment methodologies and the application of educationally appropriate principles at undergraduate and postgraduate levels. Research is undertaken by medical educationalists whose backgrounds include teaching, social sciences and medicine and related health-care specialties, and who will hold a medical or general educational diploma, degree or other appropriate postgraduate quali?cation.

Development and validation for all courses are an important part of continuing accreditation processes. The relatively conservative courses at both undergraduate and postgraduate levels, including diplomas and postgraduate quali?cations awarded by the specialist medical royal colleges (responsible for standards of specialist education) and universities, have undergone a range of reassessment and rede?nition driven by the changing needs of the individual practitioner in the last decade. The stimuli to change aspects of medical training have come from the government through the former Chief Medical O?cer, Sir Kenneth Calman, and the introduction of new approaches to specialist training (the Calman programme), from the GENERAL MEDICAL COUNCIL (GMC) and its document Tomorrow’s Doctors, as well as from the profession itself through the activities of the British Medical Association and the medical royal colleges. The evolving expectations of the public in their perception of the requirements of a doctor, and changes in education of other groups of health professionals, have also led to pressures for changes.

Consequently, many new departments and units devoted to medical education within university medical schools, royal colleges and elsewhere within higher education have been established. These developments have built upon practice developed elsewhere in the world, particularly in North America, Australia and some European countries. Undergraduate education has seen application of new educational methods, including Problem-Based Learning (PBL) in Liverpool, Glasgow and Manchester; clinical and communications skills teaching; early patient contact; and the extensive adoption of Internet (World Wide Web) support and Computer-Aided Learning (CAL). In postgraduate education – driven by European directives and practices, changes in specialist training and the needs of community medicine – new courses have developed around the membership and fellowship examinations for the royal colleges. Examples of these changes driven by medical education expertise include the STEP course for the Royal College of Surgeons of England, and distance-learning courses for diplomas in primary care and rheumatology, as well as examples of good practice as adopted by the Royal College of General Practitioners.

Continuing Professional Development (CPD) and Continuing Medical Education (CME) are also important aspects of medical education now being developed in the United Kingdom, and are evolving to meet the needs of individuals at all stages of their careers.

Bodies closely involved in medical educational developments and their review include the General Medical Council, SCOPME (the Standing Committee on Postgraduate Medical Education), all the medical royal colleges and medical schools, and the British Medical Association through its Board of Medical Education. The National Health Service (NHS) is also involved in education and is a key to facilitation of CPD/CME as the major employer of doctors within the United Kingdom.

Several learned societies embrace medical education at all levels. These include ASME (the Association for the Study of Medical Education), MADEN (the Medical and Dental Education Network) and AMEE (the Association for Medical Education in Europe). Specialist journals are devoted to research reports relating to medical educational developments

(e.g. Academic Medicine, Health Care Education, Medical Education). The more general medical journals (e.g. British Medical Journal, New England Journal of Medicine, The Lancet, Annals of the Royal College of Surgeons) also carry articles on educational matters. Finally, the World Wide Web (WWW) is a valuable source of information relating to courses and course development and other aspects of modern medical education.

The UK government, which controls the number of students entering medical training, has recently increased the quota to take account of increasing demands for trained sta? from the NHS. More than 5,700 students – 3,300 women and 2,400 men – are now entering UK medical schools annually with nearly 28,600 at medical school in any one year, and an attrition rate of about 8–10 per cent. This loss may in part be due to the changes in university-funding arrangements. Students now pay all or part of their tuition fees, and this can result in medical graduates owing several thousand pounds when they qualify at the end of their ?ve-year basic quali?cation course. Doctors wishing to specialise need to do up to ?ve years (sometimes more) of salaried ‘hands-on’ training in house or registrar (intern) posts.

Though it may be a commonly held belief that most students enter medicine for humanitarian reasons rather than for the ?nancial rewards of a successful medical career, in developed nations the prospect of status and rewards is probably one incentive. However, the cost to students of medical education along with the widespread publicity in Britain about an under-resourced, seriously overstretched health service, with sta? working long hours and dealing with a rising number of disgruntled patients, may be affecting recruitment, since the number of applicants for medical school has dropped in the past year or so. Although there is still competition for places, planners need to bear this falling trend in mind.

Another factor to be considered for the future is the nature of the medical curriculum. In Britain and western Europe, the age structure of a probably declining population will become top-heavy with senior citizens. In the ?nancial interests of the countries affected, and in the personal interests of an ageing population, it would seem sensible to raise the pro?le of preventive medicine – traditionally rather a Cinderella subject – in medical education, thus enabling people to live healthier as well as longer lives. While learning about treatments is essential, the increasing specialisation and subspecialisation of medicine in order to provide expensive, high-technology care to a population, many of whom are suffering from preventable illnesses originating in part from self-indulgent lifestyles, seems insupportable economically, unsatisfactory for patients awaiting treatment, and not necessarily professionally ful?lling for health-care sta?. To change the mix of medical education would be a di?cult long-term task but should be worthwhile for providers and recipients of medical care.... medical education

Prosthesis

An arti?cial replacement of a missing or malfunctioning body part. Examples include false legs or arms ?tted after AMPUTATION (see below); arti?cial heart valves; arti?cial heart devices; COCHLEAR IMPLANTS to improve hearing; a bio-arti?cial PANCREAS (containing live pancreatic cells from pigs) now under development to treat DIABETES MELLITUS; arti?cial bone; and (under development) arti?cal lungs. Cosmetic prostheses such as arti?cal eyes, teeth, noses and breasts are in widespread use.

Development of such mechanical and biomechanical devices points the way to a much wider use of e?ective prostheses, enabling people who would previously have died or been severely handicapped to lead normal or near normal lives. The technical hazards that have already been overcome provide a sound foundation for future successes. Progress so far in producing prostheses should also ensure that organ replacement is free from the serious ethical problems that surround the use of genetic manipulation to cure or prevent serious diseases (see ETHICS).

Limbs These are best made to meet the individual’s requirements but can be obtained ‘o? the shelf’. Arti?cial joints normally comprise complex mechanisms to stimulate ?exion and rotation movements. Leg prostheses are generally more useful than those for arms, because leg movements are easier to duplicate than those of the arm. Modern electronic circuitry that enables nerve impulses to be picked up and converted into appropriate movements is greatly improving the e?ectiveness of limb prostheses.

Eyes Arti?cial eyes are worn both for appearance and for psychological reasons. They are made of glass or plastic, and are thin shells of a boat-shape, representing the front half of the eye which has been removed. The stump which is left has still the eye-muscles in it, and so the arti?cial eye still has the power of moving with the other. A glass eye has to be replaced by a new one every year. Plastic eyes have the advantage of being more comfortable to wear, being more durable, and being unbreakable. Research is taking place aimed at creating a silicon chip that stimulates the visual cortex and thus helps to restore sight to the blind.

Dental prostheses is any arti?cial replacement of a tooth. There are three main types: a crown, a bridge and a denture. A crown is the replacement of the part of a tooth which sticks through the gum. It is ?xed to the remaining part of the tooth and may be made of metal, porcelain, plastic or a combination of these. A bridge is the replacement of two or three missing teeth and is usually ?xed in place. The replacement teeth are held in position by being joined to one or more crowns on the adjacent teeth. A denture is a removable prosthesis used to replace some or all the teeth. The teeth are made of plastic or porcelain and the base may be of plastic or metal. Removable teeth may be held more ?rmly by means of implants.

Heart The surgical replacement of stenosed or malfunctioning heart-valves with metal or plastic, human or pig valves has been routinely carried out for many years. So too has been the insertion into patients with abnormal heart rhythms of battery-driven arti?cial pacemakers (see CARDIAC PACEMAKER) to restore normal function. The replacement of a faulty heart with an arti?cial one is altogether more challenging. The ?rst working attempt to create an arti?cial heart took place in the early 1980s. Called the Jarvik-7, it had serious drawbacks: patients had to be permanently connected to apparatus the size of an anaesthetic trolley; and it caused deaths from infection and clotting of the blood. As a result, arti?cial hearts have been used primarily as bridging devices to keep patients alive until a suitable donor heart for transplantation can be found. Recent work in North America, however, is developing arti?cial hearts made of titanium and dacron. One type is planted into the chest cavity next to the patient’s own heart to assist it in its vital function of pumping blood around the body. Another replaces the heart completely. Eventually, it is probable that arti?cial hearts will replace heart transplants as the treatment of choice in patients with serious heart disorders.

Liver Arti?cial livers work in a similar way to kidney dialysis machines (see DIALYSIS). Blood is removed from the body and passed through a machine where it is cleaned and treated and then returned to the patient. The core of the device comprises several thousand ?exible membrane tubules on which live liver cells (from pigs or people) have been cultured. There is an exchange of biological molecules and water with the ‘circulating’ blood, and the membrane also screens the ‘foreign’ cells from the patient’s immune system, thus preventing any antagonistic immune reaction in the recipient.

Nose The making of a new nose is the oldest known operation in plastic surgery, Hindu records of such operations dating back to 1,000 BC. Loss of a nose may be due to eroding disease, war wounds, gun-shot wounds or dog bites. In essence the operation is the same as that practised a thousand years before Christ: namely the use of a skin graft, brought down from the forehead. Alternative sources of the skin graft today are skin from the arm, chest or abdomen. As a means of support, the new nose is built round a graft of bone or of cartilage from the ear.... prosthesis

Tacrolimus

An IMMUNOSUPPRESSANT drug used for primary immunosuppression in recipients of kidney or liver transplants (see TRANSPLANTATION) where the natural rejection process has been resistant to conventional immunosuppression regimens such as CORTICOSTEROIDS, AZATHIOPRINE and CICLOSPORIN A. It is also used, with caution, in some severe cases of eczema (see DERMATITIS).... tacrolimus

Tissue Typing

The essential procedure for matching the tissue of a recipient in need of transplanted tissue or organ to that of a potential donor. Unless there is a reasonable match, the recipient’s immune system (see IMMUNITY) will reject the donor’s organ. The main factors that are relevant to an individual’s reaction to donor tissue are called histocompatability antigens (see ANTIGEN). These are mostly human leucocyte antigens (HLAs – see HLA SYSTEM) present on the surface of cells. HLAs are inherited and, like ?ngerprints, unique to an individual, although identical twins have identical HLAs and hence are perfect matches for TRANSPLANTATION procedures.... tissue typing

Blood Transfusion, Autologous

The use of a person’s own blood, donated earlier, for blood transfusion. Autologous transfusion eliminates the slight but serious risk of contracting a serious infectious illness from contaminated blood. There is no risk of a transfusion reaction occurring as a result of incompatibility between donor and recipient blood. Up to 3.5 litres of blood can be removed and stored in several sessions at least 4 days apart and up to 3 days before planned surgery. Blood may be salvaged during surgery, filtered and returned to the circulation, reducing the need for transfusion of donated blood.... blood transfusion, autologous

Skin-grafting

An operation in which large breaches of SKIN surface due to wounding, burns or ulceration are closed by TRANSPLANTATION of skin from other parts. There are three methods by which this is done. Most frequently the epidermis only is transplanted, using a method introduced by Reverdin and by Thiersch, and known by their names. For this purpose, a broad strip of epidermis is shaved o? the thigh or upper arm, after the part has been carefully sterilised, and is transferred bodily to the raw or ulcerated surface, or is cut into smaller strips and laid upon it. A second method is for small pieces of the skin in its whole thickness to be removed from the arm and thigh, or even from other people, and then implanted and bound upon the raw surface. (This method has the disadvantage that the true skin must contract at the spot from which the graft is taken, leaving an unsightly scar.) When very large areas require to be covered, a third method is commonly used. A large ?ap of skin, amply su?cient to cover the gap, is raised from a neighbouring or distant part of the body, in such a way that it remains attached along one margin, so that blood vessels can still enter and nourish it. It is then turned so as to cover the gap; or, if it be situated on a distant part, the two parts are brought together and ?xed in this position until the ?ap grows ?rmly to its new bed. The old connection of the ?ap is then severed, leaving it growing in its new place.

Researchers are having success in growing human skin in the laboratory for grafting on to people who have been badly burned and have insu?cient intact skin surface to provide an autologous graft (one provided by the recipient of the graft). Other techniques being researched are the use of specially treated shark skin and the production of arti?cial skin.... skin-grafting

Blood Transfusion

A transmission of blood from donor to recipient subject to check for compatibility (ABO groups) and freedom from HIV, hepatitis and other viruses.

“There are as many different bloods as there are different people,” wrote Dr Alonzo J. Shadman. In his practice as a physician and surgeon he claimed he never lost a case for lack of blood and never employed blood transfusion or drugs. For bloodlessness he advised normal saline to give the heart sufficient fluid- load to work on.

Normal saline solution he used was with 2 teaspoons table salt to one of sodium bicarbonate in two quarts (approximately 2 litres) water. Normal saline keeps the blood vessels “open”.

Dr Shadman continues: “Where infection has occurred, expressed fresh juice from the flowering Marigold (Calendula) is mixed with sufficient alcohol to prevent fermentation. It should not be used full strength but diluted one part to ten parts water. Any left after the emergency should be thrown away.” (The Layman Speaks, April 1963, p. 137-139)

Garlic. Study showed a marked reduction in platelet aggregation over a 5-week period in a group of patients with normally increased tendency to aggregation. (Dr F. Jung, Department of Clinical Haemostasiology and Transfusion Medicine, Saarland University) ... blood transfusion

Lymphoma

Malignant tumour of the lymphatic system. A rare disorder. May be nodular or diffuse. The onset is encouraged by suppression of the immune system by steroids, especially in organ transplant recipients. Not the same as Hodgkin’s disease. Enlargement of lymph nodes in neck, under arm and groin. Nodes become hot, red, hardened with intense stabbing pains. (Agnus Castus, Echinacea)

Conventional treatment includes surgical extirpation, chemotherapy, radiotherapy and anti-viral drugs. Herbalism has something to offer, especially when immuno-suppression regimes are discontinued. Blood tonics and Lymphatics may stimulate recovery of a depleted immune system and include Echinacea, Goldenseal, Myrrh. Treat as for Hodgkin’s disease.

A type of lymphoma, known as Burkett’s, is usually confined to African children, believed to be of viral causation. See: ANTIVIRALS. Has been effectively treated with Vinchristine, from the plant Vinca rosea.

Treatment by or in liaison with a general medical practitioner. ... lymphoma

Blood Tests

Analysis of a sample of blood to give information on its cells and proteins and any of the chemicals, antigens, antibodies, and gases that it carries. Such tests can be used to check on the health of major organs, as well as on respiratory function, hormonal balance, the immune system, and metabolism. Blood tests may look at numbers, shape, size, and appearance of blood cells and assess the function of clotting factors. The most important tests are blood count and blood group tests if transfusion is needed. Biochemical tests measure chemicals in the blood (see acid–base balance; kidney function tests; liver function tests). Microbiological tests (see immunoassay) look for microorganisms that are in the blood, as

in septicaemia. Microbiology also looks for antibodies in the blood, which may confirm immunity to an infection. blood transfusion The infusion of large volumes of blood or blood products directly into the bloodstream to remedy severe blood loss or to correct chronic anaemia. In an exchange transfusion, nearly all of the recipient’s blood is replaced by donor blood. Before a transfusion, a sample of the recipient’s blood is taken to identify the blood groups, and it is matched with suitable donor blood. The donor blood is transfused into an arm vein through a plastic cannula. Usually, each unit (about 500 ml) of blood is given over 1–4 hours; in an emergency, 500 ml may be given in a couple of minutes. The blood pressure, temperature, and pulse are monitored during the procedure.

If mismatched blood is accidentally introduced into the circulation, antibodies in the recipient’s blood may cause donor cells to burst, leading to shock or kidney failure. Less severe reactions can produce fever, chills, or a rash. Reactions can also occur as a result of an allergy to transfused blood components. All

blood used for transfusion is carefully screened for a number of infectious agents, including HIV (the AIDS virus) and hepatitis B and hepatitis C.

In elderly or severely anaemic patients, transfusion can overload the circulation, leading to heart failure.

In patients with chronic anaemia who need regular transfusion over many years, excess iron may accumulate (haemosiderosis) and damage organs such as the heart, liver, and pancreas.

Treatment with desferrioxamine to remove excess iron may be needed.... blood tests

Graft-versus-host Disease

A complication of a bone marrow transplant in which immune system cells in the transplanted marrow attack the recipient’s tissues. Graft-versus-host (GVH) disease may occur soon after transplantation or appear some months later. The first sign is usually a skin rash. This may be followed by diarrhoea, abdominal pain, jaundice, inflammation of the eyes and mouth, and breathlessness.

GVH disease can usually be prevented by administration of immunosuppressant drugs. If the disease develops, it can be treated with corticosteroid drugs and immunosuppressant drugs such as ciclosporin In some cases, however, it can be difficult to control.... graft-versus-host disease

Immunology

The discipline concerned with the immune system. Immunologists study the immune system’s functioning and investigate and treat immune system disorders, including allergies, autoimmune disorders, and immunodeficiency disorders such as AIDS. Immunologists are also concerned with finding ways in which the immune system can be stimulated to provide immunity. In addition, they play a role in transplant surgery, looking preoperatively for a good match between recipient and donor organ, and suppressing the recipient’s immune system after transplantation to minimize the chances of organ rejection.... immunology

Rejection

An immune response aimed at destroying organisms or substances that the body’s immune system recognizes as foreign. Rejection commonly refers to the nonacceptance of tissue grafts or organ transplants. To avoid rejection, donor tissues are closely matched to the recipient (see tissue-typing). Immunosuppressant drugs, corticosteroid drugs, and ciclosporin are given to organ transplant recipients to suppress rejection.

(See also grafting; transplant surgery.)... rejection

Skin Flap

A surgical technique in which a section of skin and underlying tissue, sometimes including muscle, is moved to cover an area from which skin and tissue have been lost or damaged by injury, disease, or surgery.

Unlike a skin graft, a skin flap retains its blood supply, either by remaining attached to the donor site or through reattachment to blood vessels at the recipient site by microsurgery, so skin flaps adhere well even where there is extensive loss of deep tissue.... skin flap

Allogeneic

adj. describing grafted tissue derived from a donor of the same species as the recipient.... allogeneic

Hair Transplant

A cosmetic operation in which hairy sections of scalp are removed and transplanted to hairless areas to treat alopecia (baldness). There are several different techniques.

In strip grafting, a strip of skin and hair is taken from a donor site, usually at the back of the scalp or behind the ears. The removed hairs and their follicles are then inserted into numerous incisions made in a bald area, known as the recipient site. The procedure usually takes 60–90 minutes. The patient is given a mild sedative and anaesthetic on the donor and recipient sites. The donor site heals in about 5 days. Transplanted hairs fall out shortly afterwards, but new hairs grow from the follicles 3 weeks to 3 months later.

Other transplant techniques include punch grafting, in which a punch is used to remove small areas of bald scalp, which are replaced with areas of hairy scalp; flap grafting, in which flaps of hairy skin are lifted, rotated, and stitched to replace bald areas; and male pattern baldness reduction, which involves cutting out areas of bald skin and stretching surrounding areas of hair-bearing scalp to replace them.... hair transplant

Heart Transplant

Replacement of a patient’s damaged or diseased heart with a healthy heart taken from a donor at the time of death. Typically, transplant patients have advanced coronary artery disease or cardiomyopathy. During the operation, the function of the heart is taken over by a heart–lung machine.

Most of the diseased heart is removed, but the back walls of the atria (upper chambers) are left in place.

The ventricles (upper chambers) are then attached to the remaining areas of the recipient’s heart.

Once the immediate post-operative period is over, the outlook is good.

Patients face the long-term problems associated with other forms of transplant surgery.

(See also heart–lung transplant.)... heart transplant

Histocompatibility Antigens

A group of proteins that have a role in the immune system. Certain types of histocompatibility antigens are essential for the immunological function of killer T cells (see lymphocytes). The antigens act as a guide for killer T cells to recognize and kill abnormal or foreign cells.

The main group of histocompatibility antigens is the human leukocyte antigen (HLA) system, which consists of several series of antigens. A person’s tissue type (the particular set of HLAs in the body tissues) is unique, except for identical twins, who have the same set.

HLA analysis has some useful applications. Comparison of HLA types may show that 2 people are related, and it has been used in paternity testing. The HLA system is also used in tissue-typing to help match recipient and donor tissues before transplant surgery. Certain HLA types occur more frequently in people with particular diseases, such as multiple sclerosis, coeliac disease, and ankylosing spondylitis. HLA testing can help to confirm the presence of such diseases and identify people at risk of developing them.... histocompatibility antigens

Kidney Stone

See calculus, urinary tract.

kidney transplant An operation in which a person with chronic kidney failure receives a healthy kidney, either from a living donor or a cadaver. One donor kidney is sufficient to maintain the health of the recipient. The new kidney is placed in the pelvis through an incision in the abdomen and carefully positioned so that it can be connected easily to a nearby vein and artery and to the bladder. The diseased kidneys are left in place. The transplant avoids the need for dialysis and often allows a return to normal lifestyle. Kidney transplantation is more straightforward and common than the transplantation of any other major organ. kidney tumours Growths in the kidney. Kidney tumours may be cancerous (see kidney cancer) or noncancerous. Noncancerous ones, such as fibromas, lipomas, and leiomyomas, are often symptomless, although a haemangioma (composed of a collection of blood vessels) may grow very large and cause blood to appear in the urine. Treatment is usually not needed for noncancerous tumours unless they are large or painful, in which case they may be surgically removed.... kidney stone

Liver Transplant

Replacement of a diseased liver with a healthy liver removed from a donor. Liver transplants are most successful in the treatment of advanced liver cirrhosis in people with chronic active hepatitis or primary biliary cirrhosis. People who have primary liver cancer are rarely considered for transplantation because there is a high risk that the tumour will recur.During this procedure, the liver, gallbladder, and portions of the connected blood and bile vessels are removed.

The donor organs and vessels are connected to the recipient’s vessels.

After the transplant, the recipient is monitored in an intensive care unit for a few days and remains in hospital for up to 4 weeks.... liver transplant

Allograft

(homograft) n. a living tissue or organ graft between two members of the same species; for example, a heart transplant from one person to another. Such grafts will not survive unless the recipient is treated to suppress his body’s *immune response to the foreign tissue or the grafted organ is from an identical twin. See also transplantation.... allograft

Autologous

adj. denoting a graft or transplant that is derived from the recipient of the graft. In dentistry, autologous pulp stem cells are used in the generation of new tissue to replace damaged or defective tissue and autologous bone grafts may be used when placing dental implants.... autologous

Compatibility

n. the degree to which the body’s defence systems will tolerate the presence of intruding foreign material, such as blood when transfused or a kidney when transplanted. Complete compatibility exists between identical twins: a blood transfusion between identical twins will evoke no *antibody formation in the recipient. In severe incompatibility, for example between completely unrelated people, there are likely to be swift immune reactions as antibodies attack and destroy any offending antigenic material. See also histocompatibility; immunity. —compatible adj.... compatibility

Conjugation

n. the union of two microorganisms in which genetic material (DNA) passes from one organism to the other. In bacteria minute projections on the donor ‘male’ cell (pili) form a bridge with the recipient ‘female’ cell; the exact function of the pili is not known, but they are believed to have an important role in conjugation.... conjugation

Skin Graft

A technique used to repair areas of lost or damaged skin that are too large to heal naturally, that are slow

to heal, or that would leave tethering or unsightly scars. A skin graft is often used in the treatment of burns or sometimes for nonhealing ulcers. A piece of healthy skin is detached from one part of the body and transferred to the affected area. New skin cells grow from the graft and cover the damaged area. In a meshed graft, donor skin is removed and made into a mesh by cutting. The mesh is stretched to fit the recipient site; new skin cells grow to fill the spaces in the mesh. In a pinch graft, multiple small areas of skin are pinched up and removed from the donor site. Placed on the recipient site, they gradually expand to form a new sheet of healthy skin. (See also skin flap.)... skin graft

Tissue-typing

The classification of certain characteristics of the tissues of prospective organ donors and recipients (see transplant surgery). This minimizes the risk of rejection of a donor organ by the recipient’s immune system.

A person’s tissue type is classified in terms of their histocompatibility antigens, the most important of which are the human leukocyte antigens (HLAs), on the surface of cells. A person’s set of HLAs is inherited and unique (except for identical twins, who have the same set). Nevertheless, close relatives often have closely matching types. A person’s tissue-type is established by laboratory tests on cells from a blood sample. In one method, an antiserum containing antibodies to a particular is added to the test specimen. If the is present, it is detected by an observable colour or other change.... tissue-typing

Doctor

n. 1. a courtesy title given to a qualified medical practitioner, i.e. one who has been registered by the *General Medical Council (GMC). Most doctors in the UK obtain bachelors’ degrees in medicine and surgery (MB, BS) or the diplomas of the conjoint boards of the Royal Colleges of Physicians and Surgeons of England and Scotland or the Society of Apothecaries (e.g. LRCP, MRCS, LMSSA): these degrees or diplomas are required by the GMC before a person is provisionally registered as a doctor. Normally it is also necessary to undertake training under the medical *Foundation Programme in a hospital recognized for this purpose. Such a doctor has the title foundation doctor and is debarred from independent practice. Thereafter doctors undertake further training to be eligible for full registration on the GMC’s specialist or GP registers (see Appendix 9). Surgeons in the UK do not use the title Doctor and are referred to, as a mark of distinction, as Mr, Mrs, or Ms. Qualified dentists also use the courtesy title Doctor. See also consultant. 2. the title given to a recipient of a higher university degree than a Master’s degree (this is usually a Doctor of Philosophy (PhD or DPhil) degree). The degree Medicinae Doctor (MD) is awarded by some British universities as a research degree to those with a first degree in medicine. In the US, the degree is awarded on qualification.... doctor

Hla System

human leucocyte antigen system: a series of four gene families (termed A, B, C, and D) that code for polymorphic proteins expressed on the surface of most nucleated cells. Individuals inherit from each parent one gene (or set of genes) for each subdivision of the HLA system. If two individuals have identical HLA types, they are said to be histocompatible. Successful tissue transplantation requires a minimum number of HLA differences between donor and recipient tissues.... hla system

Immunosuppressant

n. a drug, such as *azathioprine or *cyclophosphamide, that reduces the body’s resistance to infection and other foreign bodies by suppressing the immune system. Immunosuppressants are used to maintain the survival of organ and tissue transplants and to treat various *autoimmune diseases, including rheumatoid arthritis (see disease-modifying antirheumatic drug). *Ciclosporin is the immunosuppressant usually used in organ transplant recipients. Because immunity is lowered during treatment with immunosuppressants, there is an increased susceptibility to infection and certain types of cancer.... immunosuppressant

Islet Cell Transplantation

a new technique still under evaluation for curing type 1 *diabetes mellitus, which involves the injection of donated cells from the pancreatic *islets of Langerhans into the liver, where it is hoped they will seed and survive. The transplanted cells then take over insulin production from the recipient’s diseased pancreas.... islet cell transplantation

Mlr

(MLC) mixed lymphocyte reaction (or culture): a test in which lymphocytes from prospective donor and recipient are cultured together in a test tube to assess the suitability of transplanting organs or bone marrow cells.... mlr

Oocyte Donation

(egg donation) the transfer of secondary *oocytes from one woman to another. Possible recipients include women with primary or secondary ovarian failure or severe genetic disorders, and women in whom ovulation has been suppressed as an incidental result of drug treatment for another condition (e.g. cancer). Pregnancy rates are higher than with *in vitro fertilization.... oocyte donation

Orthotopic Transplantation

transplantation of a donor organ or tissue (usually the liver) into a recipient at the site where the recipient’s organ has been removed. In contrast, heterotopic transplantation involves the preservation of the recipient’s organ in its natural site and the addition of the donor organ at another site.... orthotopic transplantation

Sperm Bank

a facility that collects, freezes, and stores human sperm for future use in *artificial insemination (see cryopreservation). Sperm is donated by men who relinquish legal rights to any future child, and donors’ identities are generally unknown to recipients. In some cases, men store their sperm for their own future use if they are to undergo a medical treatment that might leave them sterile.... sperm bank

Syngeneic

adj. describing grafted tissue that is genetically identical to the recipient’s tissue, as when the donor and recipient are identical twins.... syngeneic

Twin-to-twin Transfusion Syndrome

(TTTS) a condition in which communicating vessels in the shared placenta of monochorionic twins (see chorionicity) divert blood to one fetus (the recipient) from the other (the donor), resulting in one fetus with increased blood volume and one anaemic fetus. It complicates 15% of monochorionic twin pregnancies, and a system of ultrasound staging has been developed to assess the severity of the syndrome. TTTS is associated with a high perinatal mortality rate. There is significant morbidity and poor neurodevelopmental outcome in surviving infants due to complications of the disease itself and the high preterm birth rate that invariably accompanies this condition. A range of treatments, including *amnioreduction, *septostomy, and laser ablation of the communicating vessels, have led to an improvement in overall perinatal survival rates.... twin-to-twin transfusion syndrome



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