Genotype Health Dictionary

Genotype: From 2 Different Sources


All of an individual’s genetic information that is encoded in his or her CHROMOSOMES. It also means the genetic information carried by a pair of alleles which controls a particular characteristic. (See GENES.)
Health Source: Medical Dictionary
Author: Health Dictionary
n. 1. the genetic constitution of an individual or group, as determined by the particular set of genes it possesses. 2. the genetic information carried by a pair of alleles, which determines a particular characteristic. 3. a gene or pattern of genes the precise details of which are defined. Compare phenotype.
Health Source: Oxford | Concise Colour Medical Dictionary
Author: Jonathan Law, Elizabeth Martin

Phenotype

An individual’s characteristics as determined by the interaction between his or her genotype – quota of GENES – and the environment.... phenotype

Datura

Datura metel

Solanaceae

San: Dhustura Hin.: Kaladhatura

Ben: Dhatura Mal: Ummam Kan; Dattura

Tam: Vellummattai

Tel: Tellavummetta

Importance: Downy datura or thorn apple is an erect branched under shrub whose intoxicating and narcotic properties have been made use of by man from ancient time. The plant and fruit are spasmolytic, anticancerous and anthelmintic. Leaves and seeds are inhaled in whooping cough, asthma and other respiratory diseases. Root, leaf and seed are febrifuge, antidiarrhoeal, anticatarrhal and are used in insanity, cerebral complications and skin diseases. Leaf is antitumour, antirheumatic and vermicide. Flower is antiasthamatic, anaesthetic and is employed in swellings and eruptions on face. Fruit juice is used in earache and seed decoction in ophthalmia. For the rheumatic swellings of joints, lumbago, sciatica and neuralgia, warm leaf smeared with an oil is used as a bandage or sometimes the leaf is made into a poultice and applied. The root boiled with milk is used in insanity. It is also an ingredient in the ayurvedic preparation Kanakasva used in bronchial troubles, and the Unani formulations “Roghan dhatura” used as a massage oil for the paralysed part. The alkaloids of pharmaceutical interest present in the plant are hyoscyamine, hyoscine and meteloidine. Datura is the chief commercial source of hyoscine available from natural source. Hyoscine, in the form of hyoscine hydrobromide, is used as a pre-anaesthetic in surgery, child birth, ophthalmology and prevention of motion sickness. It is also employed in the relief of withdrawal symptoms in morphine and alcoholic addiction, paralysis agitans, post- encephaletic parkinsonianism and to allay sexual excitement. Hyoscyamine and its salt hyoscyamine sulphate and hyoscyamine hydrobromide are used in delerium, tremour, menia and parkinsonianism (Kaul and Singh, (1995).

Distribution: Datura is distributed throughout the world, particularly the warmer regions. Datura stramonium is indigenous to India. Out of 15 species reported from different parts of the world, only 10 are known to occur in India. They are found commonly in wastelands, gardens and roadsides. They are distributed in rich localities under semi -arid and arid regions of Punjab, Haryana, Rajastan, and Gujarat; the Central Plateau of Andhra Pradesh and Maharastra and the southern peninsular region of Tamil Nadu. Datura innoxia is indigenous to Mexico and is distributed in Latin American countries. A wealth of genetic stock on genotypes and varieties are maintained in several research institutes in Germany, Bulgaria, USSR and Poland.

Botany: The genus Datura, belonging to the family solanaceae, consists of annual and perennial herbs, shrubs and trees. Three species,viz, Datura metel Linn., D. stramonium Linn. and D. innoxia Mill. are medicinally important. D. innoxia mill. and D. metel Linn. (var. alba, and var, fastuosa) are the choice drug plants, rich in hyoscine. D. metel Linn. is the most common in India. The names, D. metel Linn., D. fastuosa Linn., D. alba Nees., D. fastuosa Linn. var. alba (Nees) C.B. Clarke and D. metel Linn. var. fastuosa (Linn.) Safford are synonymously used by many workers. Two varieties are often noted in D. metel Linn., namely the white flowered var. alba and purple flowered var. fastuosa. D. metel Linn. is an erect succulent branched undershrub divaricate often purplish branches and ovate pubescent leaves which are oblique at the base of lamina. Flowers are large, solitary, short pedicelled, purplish outside and white inside. Fruits are sub-globose capsules covered all over with numerous, fleshy prickles, irregularly breaking when mature. Seeds are numerous, smooth, yellowish brown. (warrier et al, 1994).

Agrotechnology: Datura grows well in a wide range of climate from tropical to temperate conditions.

The plant thrives best in areas of low rainfall where winter and monsoon rains are followed by long dry periods. Areas with annual rainfall below 1000mm with mean temperature of 10-15oC in winter and 27 - 28oC in May-June are ideal. The crop cannot stand frost, high rainfall or high temperature in the plains in May-June. It grows on majority of soils, however, alkaline or neutral clay loam soil or those tending to saline-alkaline reaction rich in organic matter are ideal for vigorous growth. The clayey, acidic, water-logged or moisture deficient soils do not suit this crop.

The plant is propagated by seeds but it is characterised by poor and often erratic seed germination which can be improved either by leaching out the inhibitor from the seeds or by alternate freezing and thawing of seeds. The optimum season for raising the crop is Rabi in tropical and subtropical areas while Kharif in temperate areas. The seeds can be broadcast - sown or seedlings can be raised in nursery and then transplanted. Seed rate is 7-8 kg/ha for broadcasting and 2-3 kg/ha. for transplanting. The field is ploughed and disced adequately to produce fine seed bed. In the case of direct seeding, seeds are drilled in rows taken 45-60 cm apart. The plants are thinned to keep a spacing of 30-45 cm at the time of first weeding. In the case of transplanting 4-6 weeks old seedlings are planted at 45-60 x 30-45 cm spacing. The field should be irrigated immediately after sowing or planting if soil moisture is inadequate. Thereafter 3-4 irrigations may be given if sufficient rainfall is not received. Application of organic manure at 10-15 t/ha and fertilisers at 60:40:40 kg N, P2O5 and K2O/ha is recommended for the crop for better growth and yield N may be applied in 3-4 equal split doses at planting and after each weeding which is required 2-3 times during the growing season. Application of micronutrients is reported to improve the alkaloid contents. No major insect pest is known to attack this crop. However, leaf spot, wilt and mosaic diseases cause damage to this crop. Leaf spot is caused by Alternaria tennuissima (Nees) Wiltshire and characterised by brown round to oval spots, becoming necrotic at later stage which leads to withering and dropping of leaves. Wilt is caused by Sclerotium rolfsii Sace; it starts with dropping of leaves and finally wilting of the entire plant. Root and foot wilt, caused by Corticium solani, appears as damping off of seedlings and mature plants. Datura distortion mosaic is characterised by yellowing of the veins followed by inward rolling and distortion of leaves with a reduction in plant size. For reducing the impact of these diseases, field sanitation, use of resistant varieties, crop rotation for 3-4 years and fungicide application should be resorted to. For the purpose of leaf and top, harvesting is done as soon as flowering starts. Entire top containing leaves and twigs is cut, dried in shade and stored in gunny bags. For seed and fruit, fully grown fruits, still green are picked 2-3 times before final harvest when the entire plant is cut from the base and dried in the open. The dried fruits are then thrashed with a stick to separate the seeds. The seed yield is 1-1.5 t/ha. (Husain, 1993; Kaul and Singh, 1995)

Properties and activity: The alkaloids hyoscyamine and hyoscine (scopolamine) and meteloidine are found in all parts of the plant. The total alkaloid content is 0.26 - 0.42 % Fruits contain daturaolone and daturadiol while roots contain additionally ditigloyloxy tropane derivatives, tigloidine, apohyoscine, norhyoscine, norhyocyamine, cusiohygrine and tropine. Other alkaloids isolated from the plant are apohyoscyamine, DL-scopolamine, normeteloidine, tigloylputrescine, scopine, nortigloidine, tropine, psuedo valeroidine, fastudine, fastunine, fastusinine, 7-hydroxy-3, 6-ditigloyloxytropane (2) datura nolone and fastusic acid. The physiological effects of hyoscyamine are qualitatively the same as those of its recemic derivative atropine. This is relatively more active in its paralysing affect on nerve endings and less active in its stimulant action on the central nervous system. The sedative and hypnotic action of hyoscyamine is weaker than that of hyoscine. Atropine has a stimulant action on the central nervous system and depresses the nerve endings to the secretary glands and plain muscles. The plant or the different alkaloids have narcotic, anthelmintic, spasmolytic anaesthetic, sedative, ophthalmic, anticancerous, antitumour, antirheumatic, antiasthmatic, antidiarrhoeal and anticatarrhal activities. (Thakur et al, 1989).... datura

Lethal Gene

A gene that produces a GENOTYPE which causes the death of an organism before that organism has reproduced – or which prevents it from reproducing. Lethal genes are usually RECESSIVE, so the organism will die only if both its ‘parents’ carry the gene. Should only one parent have the lethal gene, its consequences will be masked by the dominant ALLELE passed on by the normal parent.... lethal gene

Premna Tomentosa

Willd.

Cornulia corymbosa

Family: Verbenaceae.

Habitat: Peninsular India and Bihar up to 1,200 m.

English: Bastard Teak.

Ayurvedic: Agnimanth (var.).

Siddha/Tamil: Kolakottathekku pinari, Pondanganari.

Folk: Gineri (var.).

Action: Bark and essential oil of root—used in stomach disorders. Leaf—diuretic, vulnerary; prescribed as a tonic after child birth; used in dropsical affections. Pounded leaves—vulnerary.

The heartwood gave apigenin derivatives. The leaves gave essential oil containing d-and dl-limonene, beta- caryophyllene a sesquiterpene hydrocarbon, a diterpene hydrocarbon and a sesquiterpene tertiary alcohol.

The roots and rhizomes of P. veris and P. elatior contain a saponin, yielding a sapogenin, primulagenin A. A fla- vonol glycoside named primulaflavo- noloside has been reported in the flowers of P. veris. The root of P. veris are considered as a substitute for Senega (Polygala senega) roots.

Anthocyanidins have been detected in most of the Primula species, also a highly toxic allergenic substance, primin, in the leaves and glandular hairs. The floral and foliar parts of the different genotypes showed presence of kaempferol, quercetin and myricetin.... premna tomentosa

Uterus, Diseases Of

Absence or defects of the uterus

Rarely, the UTERUS may be completely absent as a result of abnormal development. In such patients secondary sexual development is normal but MENSTRUATION is absent (primary amennorhoea). The chromosomal make-up of the patient must be checked (see CHROMOSOMES; GENES): in a few cases the genotype is male (testicular feminisation syndrome). No treatment is available, although the woman should be counselled.

The uterus develops as two halves which fuse together. If the fusion is incomplete, a uterine SEPTUM results. Such patients with a double uterus (uterus didelphys) may have fertility problems which can be corrected by surgical removal of the uterine septum. Very rarely there may be two uteri with a double vagina.

The uterus of most women points forwards (anteversion) and bends forwards (ante?exion). However, about 25 per cent of women have a uterus which is pointed backwards (retroversion) and bent backwards (retro?exion). This is a normal variant and very rarely gives rise to any problems. If it does, the attitude of the uterus can be corrected by an operation called a ventrosuspension.

Endometritis The lining of the uterine cavity is called the ENDOMETRIUM. It is this layer that is partially shed cyclically in women of reproductive age giving rise to menstruation. Infection of the endometrium is called endometritis and usually occurs after a pregnancy or in association with the use of an intrauterine contraceptive device (IUCD – see CONTRACEPTION). The symptoms are usually of pain, bleeding and a fever. Treatment is with antibiotics. Unless the FALLOPIAN TUBES are involved and damaged, subsequent fertility is unaffected. Very rarely, the infection is caused by TUBERCULOSIS. Tuberculous endometritis may destroy the endometrium causing permanent amenorrhoea and sterility.

Menstrual disorders are common. Heavy periods (menorrhagia) are often caused by ?broids (see below) or adenomyosis (see below) or by anovulatory cycles. Anovulatory cycles result in the endometrium being subjected to unopposed oestrogen stimulation and occasionally undergoing hyperplasia. Treatment is with cyclical progestogens (see PROGESTOGEN) initially. If this form of treatment fails, endoscopic surgery to remove the endometrium may be successful. The endometrium may be removed using LASER (endometrial laser ablation) or electrocautery (transcervical resection of endometrium). Hysterectomy (see below) will cure the problem if endoscopic surgery fails. Adenomyosis is a condition in which endometrial tissue is found in the muscle layer (myometrium) of the uterus. It usually presents as heavy and painful periods, and occasionally pain during intercourse. Hysterectomy is usually required.

Oligomenorhoea (scanty or infrequent periods) may be caused by a variety of conditions including thyroid disease (see THYROID GLAND, DISEASES OF). It is most commonly associated with usage of the combined oral contraceptive pill. Once serious causes have been eliminated, the patient should be reassured. No treatment is necessary unless conception is desired, in which case the patient may require induction of ovulation.

Primary amenorrhoea means that the patient has never had a period. She should be investigated, although usually it is only due to an inexplicable delay in the onset of periods (delayed menarche) and not to any serious condition. Secondary amenorrhoea is the cessation of periods after menstruation has started. The most common cause is pregnancy. It may be also caused by endocrinological or hormonal problems, tuberculous endometritis, emotional problems and severe weight loss. The treatment of amenorrhoea depends on the cause.

Dysmenorrhoea, or painful periods, is the most common disorder; in most cases the cause is unknown, although the disorder may be due to excessive production of PROSTAGLANDINS.

Irregular menstruation (variations from the woman’s normal menstrual pattern or changes in the duration of bleeding or the amount) can be the result of a disturbance in the balance of OESTROGENS and PROGESTERONE hormone which between them regulate the cycle. For some time after the MENARCHE or before the MENOPAUSE, menstruation may be irregular. If irregularity occurs in a woman whose periods are normally regular, it may be due to unsuspected pregnancy, early miscarriage or to disorders in the uterus, OVARIES or pelvic cavity. The woman should seek medical advice.

Fibroids (leiomyomata) are benign tumours arising from the smooth muscle layer (myometrium) of the uterus. They are found in 80 per cent of women but only a small percentage give rise to any problems and may then require treatment. They may cause heavy periods and occasionally pain. Sometimes they present as a mass arising from the pelvis with pressure symptoms from the bladder or rectum. Although they can be shrunk medically using gonadorelin analogues, which raise the plasma concentrations of LUTEINISING HORMONE and FOLLICLE-STIMULATING HORMONE, this is not a long-term solution. In any case, ?broids only require treatment if they are large or enlarging, or if they cause symptoms. Treatment is either myomectomy (surgical removal) if fertility is to be retained, or a hysterectomy.

Uterine cancers tend to present after the age of 40 with abnormal bleeding (intermenstrual or postmenopausal bleeding). They are usually endometrial carcinomas. Eighty per cent present with early (Stage I) disease. Patients with operable cancers should be treated with total abdominal hysterectomy and bilateral excision of the ovaries and Fallopian tubes. Post-operative RADIOTHERAPY is usually given to those patients with adverse prognostic factors. Pre-operative radiotherapy is still given by some centres, although this practice is now regarded as outdated. PROGESTOGEN treatment may be extremely e?ective in cases of recurrence, but its value remains unproven when used as adjuvant treatment. In 2003 in England and Wales, more than 2,353 women died of uterine cancer.

Disorders of the cervix The cervix (neck of the womb) may produce an excessive discharge due to the presence of a cervical ectopy or ectropion. In both instances columnar epithelium – the layer of secreting cells – which usually lines the cervical canal is exposed on its surface. Asymptomatic patients do not require treatment. If treatment is required, cryocautery – local freezing of tissue – is usually e?ective.

Cervical smears are taken and examined in the laboratory to detect abnormal cells shed from the cervix. Its main purpose is to detect cervical intraepithelial neoplasia (CIN) – the presence of malignant cells in the surface tissue lining the cervix – since up to 40 per cent of women with this condition will develop cervical cancer if the CIN is left untreated. Women with abnormal smears should undergo colposcopy, a painless investigation using a low-powered microscope to inspect the cervix. If CIN is found, treatment consists of simply removing the area of abnormal skin, either using a diathermy loop or laser instrument.

Unfortunately, cervical cancer remains the most common of gynaecological cancers. The most common type is squamous cell carcinoma and around 4,000 new cases (all types) are diagnosed in England and Wales every year. As many as 50 per cent of the women affected may die from the disease within ?ve years. Cervical cancer is staged clinically in four bands according to how far it has extended, and treatment is determined by this staging. Stage I involves only the mucosal lining of the cervix and cone BIOPSY may be the best treatment in young women wanting children. In Stage IV the disease has spread beyond the cervix, uterus and pelvis to the URINARY BLADDER or RECTUM. For most women, radiotherapy or radical Wertheim’s hysterectomy – the latter being preferable for younger women – is the treatment of choice if the cancer is diagnosed early, both resulting in survival rates of ?ve years in 80 per cent of patients. Wertheim’s hysterectomy is a major operation in which the uterus, cervix, upper third of vagina and the tissue surrounding the cervix are removed together with the LYMPH NODES draining the area. The ovaries may be retained if desired. Patients with cervical cancer are treated by radiotherapy, either because they present too late for surgery or because the surgical skill to perform a radical hysterectomy is not available. These operations are best performed by gynaecological oncologists who are gynaecological surgeons specialising in the treatment of gynaecological tumours. The role of CHEMOTHERAPY in cervical and uterine cancer is still being evaluated.

Prolapse of the uterus is a disorder in which the organ drops from its normal situation down into the vagina. First-degree prolapse is a slight displacement of the uterus, second-degree a partial displacement and third-degree when the uterus can be seen outside the VULVA. It may be accompanied by a CYSTOCOELE (the bladder bulges into the front wall of the vagina), urethrocoele (the urethra bulges into the vagina) and rectocoele (the rectal wall bulges into the rear wall of the vagina). Prolapse most commonly occurs in middle-aged women who have had children, but the condition is much less common now than in the past when prenatal and obstetric care was poor, women had more pregnancies and their general health was poor. Treatment is with pelvic exercises, surgical repair of the vagina or hysterectomy. If the woman does not want or is not ?t for surgery, an internal support called a pessary can be ?tted – and changed periodically.

Vertical section of female reproductive tract (viewed from front) showing sites of common gynaecological disorders.

Hysterectomy Many serious conditions of the uterus have traditionally been treated by hysterectomy, or removal of the uterus. It remains a common surgical operation in the UK, but is being superseded in the treatment of some conditions, such as persistent MENORRHAGIA, with endometrial ablation – removal of the lining of the uterus using minimally invasive techniques, usually using an ENDOSCOPE and laser. Hysterectomy is done to treat ?broids, cancer of the uterus and cervix, menorrhagia, ENDOMETRIOSIS and sometimes for severely prolapsed uterus. Total hysterectomy is the usual type of operation: it involves the removal of the uterus and cervix and sometimes the ovaries. After hysterectomy a woman no longer menstruates and cannot become pregnant. If the ovaries have been removed as well and the woman had not reached the menopause, hormone replacement therapy (HRT – see MENOPAUSE) should be considered. Counselling helps the woman to recover from the operation which can be an emotionally challenging event for many.... uterus, diseases of

Genetic Screening

*screening tests to discover individuals whose *genotypes are associated with specific diseases. Such individuals may later develop the disease itself or pass it on to their children (see carrier). The recent use of genetic screening to diagnose the sex of the fetus so that the parents may ‘choose’ the sex of their children has caused considerable controversy. See also mouthwash test; preimplantation genetic diagnosis.... genetic screening



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