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Biomedical subjects

G Perret

Publications and source records attributed to G Perret.

At least 91 records · Page 5Linked to original sources
PubMed1977

Neurosurgical control of pain in the patient with cancer.

If properly evaluated, the majority of patients with intractable pain caused by visceral as well as somatic malignancy can obtain relief. Analgesics are of great value in some cases. They are especially indicated for patients who have conditions producing pain of short duration or for terminal patients. Radiotherapy may temporarily help most patients with intractable pain. Open or stereotactic surgical intervention and especially interruption of the ascending pain fibers within the spinal cord may give permanent relief to patients who have increasingly severe pain. At present the best results are obtained with percutaneous high cervical electrocoagulation of the spinothalamic tracts. Experience with electrical inhibition of pain based on the gate theory is limited. In the future, however, it may replace the present destructive approaches.

Brain↗
PubMed1976

A fraction isolated from porcine upper small intestine stimulating pepsin secretion in the cat.

The preliminary purification of a material, apparently distinct from any hitherto isolated gastrointestinal hormone, with pepsin release stimulating activity in the cat is described. This material has shown no inhibitory effect on pentagastrin-stimulated secretion of acid, no effect of its own on gastric acid secretion and antral motility, and only a weak stimulatory effect on pancreatic secretion of bicarbonate.

Animals↗
PubMed1976

Effect of duodenal acidification on gastric mucus and acid secretion in conscious cats.

In cats with gastric fistulae and Heidenhein pouches, the effect of acid entering the duodenum on secretion of acid, pepsin, and mucus from the Heidenhain pouch during maximal acid stimulation with pentagastrin or histamine, was studied. Duodenal acidification produced stimulation of pepsin and mucus secretion comparable to that induced by exogenous hormones (secretin and the combination of secretin with cholecystokinin). In addition, duodenal acidification caused an increase in acid secretion, thus suggesting that, in addition to secretin and cholecystokinin, a factor that stimulates acid secretion was also released by acid.

Animals↗
PubMedDate not supplied

Diclofenac, paracetamol, and vidarabine removal during plasma exchange in polyarteritis nodosa patients.

Since plasma exchange (PE) represents a major treatment for patients suffering from systemic diseases, its influence on the kinetics of three drugs was investigated: vidarabine, used in patients with polyarteritis nodosa associated with hepatitis B virus (eight subjects), and diclofenac and paracetamol for investigative purposes (five subjects). This study confirmed that vidarabine is so rapidly deaminated to form hypoxanthine arabinoside (Hx-Ara) that no detectable concentrations were measured. Hx-Ara levels were used to evaluate vidarabine kinetics; 19.5 +/- 14.6 mg of Hx-Ara were removed by one PE during the first week of treatment (15 mg kg-1 d-1, continuous infusion) and 7.8 +/- 10.2 mg were eliminated by one PE during the second week of treatment (7.5 mg kg-1 d-1, continuous infusion). Based on the vidarabine intake per hour and the resulting quantity of Hx-Ara removed per hour, PE recovery was quite important (ca. 30 per cent), during both the first and second weeks of continuous infusion. Data were subject to large interindividual variability. However, these results do not favor vidarabine dosage supplementation in this indication because the duration of PE is less than 8 per cent of a daily administration period. For paracetamol (1 g, single oral dose) and diclofenac (100 mg, single oral dose), the fractions of drug removed during PE effected within 2 h of drug intake, were respectively 5.0 +/- 3.1 per cent and 13.6 +/- 9.5 per cent, while plasmapheretic clearance reached, respectively, 13.0 +/- 10.7 per cent of the systemic clearance for paracetamol and 23.0 +/- 1.0 per cent for diclofenac.

Acetaminophen↗
PubMedDate not supplied

Influence of renal function on the pharmacokinetics of diacerein after a single oral dose.

The pharmacokinetics of diacetylrhein following a single oral dose of 50 mg was studied in 12 healthy volunteers and two groups of 8 patients with mild or severe renal insufficiency. Statistical analysis using a Kruskal-Wallis rank sum test showed a significant difference between the three groups for the following parameters. In severely uraemic patients, median AUC0-infinity was multiplied by a factor of about 2: 40.5 mg.h/l versus 21.3 mg.h/l in healthy subjects, P = 0.04; and t1/2 was prolonged by the same factor: 9.6 h versus 4.3 h in the control group, P = 0.003. Apparent drug availability and renal clearance assessed through urinary data decreased with renal failure, respectively: 14.5% and 0.045 l/h versus 35.4% (P = 0.01) and 0.13 l/h (P = 0.008) in healthy subjects. Amounts of glucuro- and sulpho-conjugates in urine were lower in severely uraemic patients. Intermediate values were observed for mildly uraemic patients. Other parameters: lag time, Cmax, tmax, Vss/F, urinary glucuro- to sulpho-conjugate ratios did not change significantly. Apparent total clearance of rhein was poorly correlated with creatinine clearance and this was related to a decrease of non-renal clearance of rhein in renal insufficiency. It was concluded that, from a pharmacokinetic point of view, a reduction (50%) in the initial dosage of diacerein should be considered in severe renal failure.

Adult↗
PubMedDate not supplied

[Forensic medicine experiences with methadone substitution in the Geneva canton].

Methadone treatment for heroin addiction has followed three distinct periods in Geneva, Switzerland. The first period (1970-1979) corresponds to the beginning of the heroin addiction epidemic. Treatment was restricted to detoxification and did not succeed in reducing fatal overdoses. During the second period (1980-1989), methadone maintenance program was favoured but access to this program was limited. This period has brought a decrease of illegal heroin consumption and criminality but not of fatal overdoses. Finally, during the third period (since 1990), legislation was changed to allow easier access to methadone maintenance program. As a consequence there was a significant drop in lethal heroin overdoses and in deaths attributed to HIV.

Cause of Death↗
PubMedDate not supplied

[Radioreceptor assay: principles and applications to pharmacology].

The aim of the first part of this work is to present the theory of the radioreceptor assay and to compare it to the other techniques of radioanalysis (radioimmunoassay, competitive protein binding assays). The technology of the radioreceptor assay is then presented and its components (preparation of the receptors, radioligand, incubation medium) are described. The analytical characteristics of the radioreceptor assay (specificity, sensitivity, reproducibility, accuracy) and the pharmacological significance of the results are discussed. The second part is devoted to the description of the radioreceptor assays of some pharmacological classes (neuroleptics, tricyclic antidepressants, benzodiazepines, beta-blockers, anticholinergic drugs) and to their use in therapeutic drug monitoring. In conclusion, by their nature, radioreceptor assays are highly sensitive, reliable, precise, accurate and simple to perform. Their chief disadvantage relates to specificity, since any substance having an appreciable affinity to the receptor site will displace the specifically bound radioligand. Paradoxically in some cases, this lack of specificity may be advantageous in that it allows for the detection of not only the apparent compound but of active metabolites and endogenous receptor agonists as well and in that radioreceptors assays can be devised for a whole pharmacological class and not only for one drug as it is the case for classical physico-chemical techniques. For all these reasons future of radioreceptor assay in pharmacology appears promising.

Adrenergic beta-Antagonists↗