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Biomedical subjects

G Mion

Publications and source records attributed to G Mion.

At least 19 recordsLinked to original sources

[Ketamine: drug facts, uses in anesthesia, and new applications for analgesia].

Ketamine is an anesthetic drug of choice in tropical zones. In addition to excellent pharmocologic properties and low cost, it offers the possibility of using a variety of administration routes and of performing invasive procedures with spontaneous ventilation. Adverse psychodysleptic effects can be prevented by association with midazolam or propofol. Hypersalivation can be prevented with atropine. Recent experience has shown that thanks to its antihyperalgesic effects ketamine can be used for postoperative analgesia at doses ten times lower than for anesthesia.

Analgesia↗

Tachycardia and convulsions induced by accidental intravascular ropivacaine injection during sciatic block.

Ropivacaine, a recently introduced local anesthetic of the amide family (1), seems to show less toxicity than bupivacaine (2-4). Nevertheless, both neurologic and cardiovascular toxicities are possible. Six cases of ropivacaine-induced convulsions have previously been reported (5-10), of which three cases also showed cardiovascular toxicity. In three cases, total plasma concentrations were measured (Table 1).

Adult↗

[Action of venoms on blood coagulation: diagnosis of hemorrhagic syndromes].

Venoms from Viperidae, Crotalidae, some Australian Elapidae and few Colubridae are a mixture of enzymes which impact on blood coagulation in several ways. These proteins can be classified as haemorragins which induce disorders of the capillary permeability, disintegrins and related proteins which disturb the clotting time while acting on plate adhesion, and proteases which cleave peptides. Venoms contain molecules directed against several targets of the coagulation system. The same molecule may present different activities. Components of snake venoms are used in diagnostic coagulation tests, fundamental research and as drugs against infectious agents, cancer or haematological disorders. The structural differences between proteins from snake venoms and natural coagulation factors and the target diversity of the venom components explain why it remains illusory to treat bleedings when acting just at symptom level. Conversely, antivenom, whose components are directed against the venom proteins, is the only aetiological therapy effective against snake envenomations.

Animals↗

[Clinical and biological surveillance of envenomed patients].

Faced with an envenomation, the problem is to take sufficiently rapidly the decision to administer the only effective treatment--immunotherapy--, to know which antivenom to choose and how long to administrate it. If the snake is not identified, symptoms and initial development give information on the type of venom. It is convenient to classify the symptoms according to four clinical types: i) the cobra syndrome with a potentially fatal evolution within two to ten hours and which resembles an Elapid bite, ii) the viper syndrome associating bleeding and inflammation, which can be due either to a viper, pit viper or, in Australia, to Elapids, iii) disturbance of blood circulating functions and iv) disturbance of other live functions. Between the third to the half of snakebite victims present no envenomation. Severe envenomations must be monitored in an intensive care unit, with experience in emergency management and monitoring of patients with major life-threatening conditions. Throughout the world, snakebites induce more than 100,000 deaths every year. Schematically, the emergency may be considered in terms of seconds for blood circulation disorders, minutes for respiratory paralysis, and hours for the coagulopathy.

Algorithms↗

Round table and synthesis of the meeting.

Our knowledge of the epidemiology of scorpion stings and snakebites remains fragmentary but sufficient, nevertheless, to be able to confirm that envenomations constitute a real public health problem throughout Africa. In order for the health authorities to be able to improve management of this problem, data collection must be enhanced. The objective should be to determine what kinds of intervention are necessary (quantity of antivenom serum and drugs, in particular) and where they should be applied. Specialists must come to a rapid consensus for a simple therapeutic protocol to be used in peripheral health centres where means are often scarce. Training for health personnel is also insufficient. Appropriate courses must be organised for medical doctors and nurses within both their basic and on-going training. These courses must necessarily involve health personnel from rural zones must affected by envenomations. The availability of antivenom serum--the only specific, efficacious drug--must be improved as soon as possible. If quantitative and geographic needs can be determined by epidemiological studies, then distribution must be developed by original means (grouping orders at national level, direct orders) and diversified financial support (purchase on the open market, local authority grants, community participation). The symposium attendees agreed to meet again within two years' time to evaluate progress in the area.

Africa↗

[Hypertensive effects of qat].

Chewing of Qat leaves which contain amphetamine alkaloids is a traditional drug practice in the horn of Africa. Cathine and cathinone are responsible for the desired psychogenic (suppression of hunger, mind stimulation, euphoria) and sympathicomimetic effects. In this study, we monitored seven volunteers during a traditional qat ritual. An increase in systolic and diastolic pressure was observed in three patients including one presenting predisposing chronic arterial hypertension. Peak pressure was observed approximately seven hours after beginning the ritual. The three patients presenting pressure changes were not significantly different from the four unaffected patients with regard to age or duration of qat use. These findings suggest that qat use by untreated hypertensive patients who react strongly to vasoconstrictive effects can lead to hypertension and resulting cardiovascular complications.

Adult↗

[Epidemiologic study of qat use in the National Army of Djibouti].

Chewing of qat leaves is a traditional practice in the horn of Africa. Amphetamine-like alkaloids contained in the leaves account for the psychostimulating (anorexia, exhiliaration, euphoria) and sympathomimetic effects. The results of this prospective study based on interviews of 100 servicemen seeking medical advice showed that the prevalence of qat use in the National Army of Djibouti was 84%. Mean consumption of qat by users was 400 +/- 50 grams per chew requiring a monthly expenditure of approximately 500 FF. Heart rate and blood pressure in users were not significantly different from non-users. No correlation was found between blood pressure and either age or quantity of qat ingested per chew. A greenish discoloration of the tongue was observed in 65% of qat users but this sign was not specific (60%). qat use was correlated with poor dental health. The findings of this study indicate that qat use is widespread among young males in Djibouti but that its cardiovascular effects are limited in this age group.

Adult↗