Sex reversal on y Health Dictionary

R. Br.

Family: Apocynaceae.

Habitat: Peninsular India.

Folk: Pazh-munipala (Tamil), Addasarpa (Kannada), Palamunpala (Malyalam).

Action: Stembark and fruit— antiepileptic.

The plant is a rich source of indole alkaloids. Major alkaloids in the stem- bark are alstovenine, venenatine, 3- dehydroalstovenine, reserpine (0.0030.3%), venoxidine and kopsinine.

Alstovenine, in lower doses, exhibits monoamine oxidase inhibitor activity; in higher doses, shows marked central stimulant effect (reversal of reserpine effects). Venenatine exhibits reserpine- like profile of activity (sedation, ptosis, reduction in motor activity).

The fruit contains vincadifformine type of alkaloids. Echitovenidine, the major alkaloid, shows monoamine oxidase-inhibitory activity both in vitro and in vivo.... alstonia venenata

Linn.

Family: Ginkgoaceae.

Habitat: Native to China and Japan; cultivated in Indian gardens as an ornamental.

English: Maidenhair tree called Living Fossils (in India), Kew tree.

Action: Antagonizes bronchospasm, used as a circulatory stimulant, peripheral vasodilator.

Key application: Standardized dry extract—for symptomatic treatment of disturbed performance in organic brain syndrome within the regimen ofa therapeutic concept in cases of dementia syndromes— memory deficits, disturbance in concentration, depressive emotional conditions, dizziness, tinnitus and headache. (German Commission E, ESCOP, WHO.) As vasoactive and platelet aggregation inhibitor.

(The British Herbal Pharmacopoeia.) (For pharmocological studies in humans and clinical studies, see ESCOP.)

The majority of pharmacological studies and clinical trials have been conduced using a standardized extract which contains 24% flavonoid glyco- sides (Ginko flavone glycosides) and 6% terpenoids (ginkgolides and bilob- alide).

The extract increases tolerance to hypoxia and exhibits anti-ischaemic effect. It simultaneously improves the fluidity of blood, decreases platelet adhesion, decreases platelet and erythro- cyte aggregation and reduces plasma and blood viscosity. The extract protects erythrocytes from haemolysis. The extract also decreases the permeability of capillaries and protects the cell membrane by trapping deleterious free radicals.

The extract also increased cerebral blood flow in about 70% patients evaluated (patients between 30-50 year age had 20% increase from the base line, compared with 70% in those 50- to 70- year-olds).

A reversal of sexual dysfunction with concurrent use of ginkgo with antidepressant drugs has been reported. (Am J Psychiatry, 2000 157(5), 836837.)

The National Centre for Complementary and Alternative Medicine, USA, is conducting a 5-year study of 3000 people aged 75 and older to determine if ginkgo, 240 mg daily, prevents dementia or Alzheimer's disease.... ginkgo biloba

Increase in size of hands, feet, skull, and jaw by excessive bone growth, associated with expanding tumour of the pituitary gland. Bones become longer and the voice deepens. The change is usually gradual, the face becoming elongated and the features coarse due to thickened skin. Lips, nose and tongue enlarge. Mandible is prominent (prognathism), frontal sinuses enlarge and brows have a beetling appearance. A complexity of symptoms include: ill-fitting dentures, bite reversal, headache, enlarged fingers requiring ring to be moved from fourth to fifth finger. Shoes get tight, spine kyphotic and stiff, possible carpal syndrome, overt diabetes and visual defects.

The condition is irreversible thus no cure is possible. However, pituitary gland normalisers can assist and possibly avert decline.

Alternatives. Tea: Combine equal parts: Gotu Kola, Yarrow, Horsetail. 1 heaped teaspoon to each cup boiling water; infuse 15 minutes. 1 cup once or more daily.

Tablets/capsules. Bladderwrack, Borage, Kelp, Liquorice, Ginseng, Wild Yam, Damiana, Helonias. Formula. Combine: Sarsaparilla 1; Ginseng 1; Fringe Tree half; Thuja quarter. Dose: Powders, quarter of a teaspoon. Liquid extracts: 30-60 drops. Tinctures: 1-2 teaspoons. In water, morning and evening. ... acromegaly

prefix denoting 1. removal or loss. Examples: demineralization (of minerals from bones or teeth); devascularization (of blood supply). 2. reversal.... de

n. the branch of surgery in which extremely intricate operations are performed through highly refined *operating microscopes using miniaturized precision instruments (forceps, scissors, needles, etc.). The technique enables surgery of previously inaccessible parts of the eye, inner ear, spinal cord, and brain (e.g. for the removal of tumours and repair of cerebral aneurysms), as well as the reattachment of amputated fingers (necessitating the suturing of minute nerves and blood vessels) and the reversal of vasectomies.... microsurgery

sex reversal on Y. See Y chromosome.... sry

n. the surgical operation of reanastomosing the vas deferens after previous vasectomy: the reversal of vasectomy, undertaken to restore fertility. It is ideally performed using microsurgical techniques. The success rates vary depending on the time between the vasectomy and its reversal.... vasovasostomy

a sex chromosome that is present in men but not in women. It carries the SRY (sex reversal on Y) gene, which encodes a protein (testis-determining factor, or SRY protein) that switches the default female pathway of embryonic development to the male pathway by initiating testis formation. Compare X chromosome.... y chromosome

The loss or absence of sensation or feeling. Commonly used to describe a reversible process which allows operations and painful or unpleasant procedures to be performed without distress to the patient.

The speciality of anaesthesia broadly covers its provision for SURGERY, intensive therapy (intensive care), chronic pain management, acute pain management and obstetric analgesia. Anaesthetists in Britain are trained specialists with a medical degree, but in many countries some anaesthetists may be nurse practitioners working under the supervision of a medical anaesthetist.

The anaesthetist will assess the patient’s ?tness for anaesthesia, choose and perform the appropriate type of anaesthetic while monitoring and caring for the patient’s well-being, and, after the anaesthetic, supervise recovery and the provision of post-operative pain relief.

Anaesthesia may be broadly divided into general and local anaesthesia. Quite commonly the two are combined to allow continued relief of pain at the operation site after the patient awakens.

General anaesthesia is most often produced by using a combination of drugs to induce a state of reversible UNCONSCIOUSNESS. ‘Balanced’ anaesthesia uses a combination of drugs to provide unconsciousness, analgesia, and a greater or lesser degree of muscle relaxation.

A general anaesthetic comprises induction, maintenance and recovery. Historically, anaesthesia has been divided into four stages (see below), but these are only clearly seen during induction and maintenance of anaesthesia using inhalational agents alone.

(1) Onset of induction to unconsciousness

(2) Stage of excitement

(3) Surgical anaesthesia

(4) Overdosage

Induction involves the initial production of unconsciousness. Most often this is by INTRAVENOUS injection of a short-acting anaesthetic agent such as PROPOFOL, THIOPENTONE or ETOMIDATE, often accompanied by additional drugs such as ANALGESICS to smooth the process. Alternatively an inhalational technique may be used.

Maintenance of anaesthesia may be provided by continuous or intermittent use of intravenous drugs, but is commonly provided by administration of OXYGEN and NITROUS OXIDE or air containing a volatile anaesthetic agent. Anaesthetic machines are capable of providing a constant concentration of these, and have fail-safe mechanisms and monitors which guard against the patient’s receiving a gas mixture with inadequate oxygen (see HYPOXIC). The gases are adminstered to the patient via a breathing circuit either through a mask, a laryngeal mask or via ENDOTRACHEAL INTUBATION. In recent years, concerns about side-effects and pollution caused by volatile agents have led to increased popularity of total intravenous anaesthesia (TIVA).

For some types of surgery the patient is paralysed using muscle relaxants and then arti?cially ventilated by machine (see VENTILATOR). Patients are closely monitored during anaesthesia by the anaesthetist using a variety of devices. Minimal monitoring includes ELECTROCARDIOGRAM (ECG), blood pressure, PULSE OXIMETRY, inspired oxygen and end-tidal carbon-dioxide concentration – the amount of carbon dioxide breathed out when the lungs are at the ‘empty’ stage of the breathing cycle. Analgesic drugs (pain relievers) and local or regional anaesthetic blocks are often given to supplement general anaesthesia.

Volatile anaesthetics are either halogenated hydrocarbons (see HALOTHANE) or halogenated ethers (iso?urane, en?urane, des?urane and sevo?urane). The latter two are the most recently introduced agents, and produce the most rapid induction and recovery – though on a worldwide basis halothane, ether and chloroform are still widely used.

Despite several theories, the mode of action of these agents is not fully understood. Their e?cacy is related to how well they dissolve into the LIPID substances in nerve cells, and it is thought that they act at more than one site within brain cells – probably at the cell membrane. By whatever method, they reversibly depress the conduction of impulses within the CENTRAL NERVOUS SYSTEM and thereby produce unconsciousness.

At the end of surgery any muscle relaxant still in the patient’s body is reversed, the volatile agent is turned o? and the patient breathes oxygen or oxygen-enriched air. This is the reversal or recovery phase of anaesthesia. Once the anaesthetist is satis?ed with the degree of recovery, patients are transferred to a recovery area within the operating-theatre complex where they are cared for by specialist sta?, under the supervision of an anaesthetist, until they are ready to return to the ward. (See also ARTIFICIAL VENTILATION OF THE LUNGS.) Local anaesthetics are drugs which reversibly block the conduction of impulses in nerves. They therefore produce anaesthesia (and muscle relaxation) only in those areas of the body served by the nerve(s) affected by these drugs. Many drugs have some local anaesthetic action but the drugs used speci?cally for this purpose are all amide or ester derivatives of aromatic acids. Variations in the basic structure produce drugs with di?erent speeds of onset, duration of action and preferential SENSORY rather than MOTOR blockade (stopping the activity in the sensory or motor nerves respectively).

The use of local rather than general anaesthesia will depend on the type of surgery and in some cases the unsuitability of the patient for general anaesthesia. It is also used to supplement general anaesthesia, relieve pain in labour (see under PREGNANCY AND LABOUR) and in the treatment of pain in persons not undergoing surgery. Several commonly used techniques are listed below:

LOCAL INFILTRATION An area of anaesthetised skin or tissue is produced by injecting local anaesthetic around it. This technique is used for removing small super?cial lesions or anaesthetising surgical incisions.

NERVE BLOCKS Local anaesthetic is injected close to a nerve or nerve plexus, often using a peripheral nerve stimulator to identify the correct point. The anaesthetic di?uses into the nerve, blocking it and producing anaesthesia in the area supplied by it.

SPINAL ANAESTHESIA Small volumes of local anaesthetic are injected into the cerebrospinal ?uid through a small-bore needle which has been inserted through the tissues of the back and the dura mater (the outer membrane surrounding the spinal cord). A dense motor and sensory blockade is produced in the lower half of the body. How high up in the body it reaches is dependent on the volume and dose of anaesthetic, the patient’s position and individual variation. If the block is too high, then respiratory-muscle paralysis and therefore respiratory arrest may occur. HYPOTENSION (low blood pressure) may occur because of peripheral vasodilation caused by sympathetic-nerve blockade. Occasionally spinal anaesthesia is complicated by a headache, perhaps caused by continuing leakage of cerebrospinal ?uid from the dural puncture point.

EPIDURAL ANAESTHESIA Spinal nerves are blocked in the epidural space with local anaesthetic injected through a ?ne plastic tube (catheter) which is introduced into the space using a special needle (Tuohy needle). It can be used as a continuous technique either by intermittent injections, an infusion or by patient-controlled pump. This makes it ideal for surgery in the lower part of the body, the relief of pain in labour and for post-operative analgesia. Complications include hypotension, spinal headache (less than 1:100), poor e?cacy, nerve damage (1:12,000) and spinal-cord compression from CLOT or ABSCESS (extremely rare).... anaesthesia

Also known as Hansen’s disease, this is a chronic bacterial infection caused by Mycobacterium leprae affecting the skin, mucous membranes, and nerves. Infection is now almost con?ned to tropical and subtropical countries – mostly in Africa and India. There are two distinct (polarised) clinical forms: tuberculoid and lepromatous. The former usually takes a benign course and frequently burns out, whereas the latter is relentlessly progressive; between these two polar forms lies an intermediate/dimorphous group. Susceptibility may be increased by malnutrition. Nasal secretions (especially in lepromatous disease) are teeming with M. leprae and constitute the main source of infection; however, living in close proximity to an infected individual seems necessary for someone to contract the disease. M. leprae can also be transmitted in breast milk from an infected mother.

Only a small minority of those exposed to M. leprae develop the disease. The incubation period is 3–5 years or longer. The major clinical manifestations involve skin and nerves: the former range from depigmented, often anaesthetic areas, to massive nodules; nerve involvement ranges from localised nerve swelling(s) to extensive areas of anaesthesia. Advanced nerve destruction gives rise to severe deformities: foot-drop, wrist-drop, claw-foot, extensive ulceration of the extremities with loss of ?ngers and toes, and bone changes. Eye involvement can produce blindness. Laryngeal lesions produce hoarseness and more serious sequelae. The diagnosis is essentially a clinical one; however, skin-smears, histological features and the lepromin skin-test help to con?rm the diagnosis and enable the form of disease to be graded.

Although the World Health Organisation had originally hoped to eliminate leprosy worldwide by 2000, that has proved an unrealistic target. The reason is an absence of basic information. Doctors are unable to diagnose the disorder before a patient starts to show symptoms; meanwhile he or she may have already passed on the infection. Doctors do not know exactly how transmission occurs or how it infects humans – nor do they know at what point a carrier of the bacterium may infect others. The incidence of new infections is still more than 650,000 cases a year or about 4.5 cases per 10,000 people in those countries worst affected by the disease.

Treatment Introduction of the sulphone compound, dapsone, revolutionised management of the disease. More recently, rifampicin and clofazimine have been added as ?rst-line drugs for treatment. Second-line drugs include minocycline, o?oxacin and clarithromycin; a number of regimens incorporating several of these compounds (multi-drug regimens – introduced in 1982) are now widely used. A three-drug regime is recommended for multi-bacillary leprosy and a two-drug one for parcibacillary leprosy. Dapsone resistance is a major problem worldwide, but occurs less commonly when multi-drug regimens are used. Older compounds – ethionamide and prothionamide

– are no longer used because they are severely toxic to the liver. Corticosteroids are sometimes required in patients with ‘reversal reaction’. Supportive therapy includes physiotherapy; both plastic and orthopaedic surgery may be necessary in advanced stages of the disease. Improvement in socio-economic conditions, and widespread use of BCG vaccination are of value as preventive strategies. Early diagnosis and prompt institution of chemotherapy should prevent long-term complications.... leprosy