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Biomedical subjects

A Roux

Publications and source records attributed to A Roux.

At least 55 records · Page 3Linked to original sources
PubMed1990

Causes of mental handicap in Cape Town.

A cross-cultural study of the cause of the mental handicap of greater than 1,000 children born in the Cape Town area between 1974 and 1986 was carried out. Acquired causes were noted to be more prevalent among the black ethnic group. This study showed that at least 80-100 additional cases of moderate-severe mental handicap can be expected in the Cape Town area each year. Attention is drawn to the expanded facilities that will be required to provide for the ongoing special needs of these children. Possible areas for prevention of mental handicap are discussed.

Adolescent↗
PubMed1990

Vertebro-PICA aneurysms: midline suboccipital approach and laminectomy of the atlas.

Vertebro-PICA aneurysms represent a particular technical challenge because of the extremely narrow operative field and the presence of numerous vital neural and vascular structures. The lack of exposure still remains the limiting factor in most cases. During the 9-year period from January 1980 to October 1989, 8 vertebro-PICA aneurysms have been treated microsurgically. Of these, 2 underwent a pure suboccipital approach while 6 underwent a midline suboccipital approach with deliberate removal of the arch of the atlas in the park bench position. Seven patients did well and regained full activities while one patient died from complications related to vasospasm with brainstem infarction. One patient developed symptomatic obstructive dilation of the fourth ventricle requiring ventriculo-cisternostomy. The authors recommend the midline suboccipital approach with deliberate C1-laminectomy in ventrolateral decubitus for vertebro-PICA aneurysms. The main advantages are: constant access to the proximal vertebral artery, less medullary retraction in ventrally located aneurysms, improved exposure of the laterobulbar cisterns and the lateromedullary and tonsillar segments of the PICA, thus facilitating dissection of the aneurysm.

Adult↗
PubMed1989

Natural mode of horizontal transmission of bovine leukemia virus (BLV): the potential role of tabanids (Tabanus spp.).

In order to evaluate the potential role of hematophagous insects in the natural spreading of bovine leukemia virus (BLV) infection in cattle, a 2-year survey was carried out involving sequential serological tests on 3328 cattle in three different areas. A parallel entomological study was run over the same period, using continuous trapping, in order to determine both the density and variations of horsefly (Tabanus spp.) populations in the close vicinity of the herds. After statistical analysis, this space-time study showed that: (1) There is a significant positive geographical correlation between the rate of incidence of BLV infection and the density of the horsefly population. (2) Seasonal variations in the incidence rate exist; the highest rates are generally observed during summer (from July of September), and the lowest during winter, spring and early summer (from November to mid-July). (3) There is a time link between the rate of sero-conversion and the variations in activity of the horsefly population. All these data combined would appear to indicate that tabanids play a considerable role in the spread of BLV under natural conditions.

Animals↗
PubMed1989

Pharmacokinetics of ketoprofen in man after repeated percutaneous administration.

A topical formulation of ketoprofen, a widely used nonsteroidal antiinflammatory drug, has recently been developed. Ten healthy young subjects (mean age 23.5 +/- 2.5 years) received daily 15 g of 2.5% ketoprofen gel, corresponding to 375 mg on the skin of the back over an area of 750 cm2. Plasma samples were collected after the first dose and after 10 days of chronic treatment. Urine was also collected. Ketoprofen was assayed by HPLC. The peak plasma concentration was 144 +/- 91 ng/ml after the first administration with apparent absorption and elimination half-lives of 3.2 +/- 2.4 h and 27.7 +/- 18.0 h, respectively. The total quantities of ketoprofen eliminated in the urine represented about 2.6% of the first dose applied. At the end of the study, the apparent half-life of unchanged ketoprofen was 17.1 +/- 9.1 h, and there was no accumulation. In this study, no sign of local intolerance was seen.

Administration, Cutaneous↗
PubMed1988

[Application of a method of analysis using high performance liquid chromatography of isoniazid and acetylisoniazid to determine the phenotype of acetylation].

The described method is adapted from Moulin to measure plasma levels of isoniazid (INH) and acetylisoniazid (AINH) after extraction, HPLC separation and UV detection (254 nm). INH and AINH plasma levels of 109 patients aged between four months to 87 years were measured, allowing dosage individualization. The ratio of AINH to INH (Rm) three hours after administration was calculated. Rm allows determination of the patient acetylation phenotype: in fast acetylators with INH half-life shorter than 1.8 h, Rm is greater than 0.77 and in slow acetylators with INH half-life longer than 1.8 h, Rm is less than 0.48.

Acetylation↗
PubMed1986

Comparison between theophylline analysis by nephelometric inhibition immunoassay and high performance liquid chromatography.

Rate nephelometric inhibition immunoassay (NIIA) was used to determine 94 serum theophylline concentrations, and these results were compared with those obtained using high performance liquid chromatography (HPLC) as a reference method. The measurements obtained by the nephelometric method were, on the average, 20% higher than those obtained by the chromatographic method (p less than 0.001). The coefficient of variation of the nephelometric method was 12.3%, compared with 3.9% for the chromatographic reference method. In the group of subjects having a serum concentration of caffeine greater than or equal to 0.5 microgram ml-1, the difference in serum theophylline concentration found between NIIA and HPLC correlated with serum caffeine concentration (r = 0.3755, df = 46, p less than 0.01). NIIA theophylline concentration was 8.8 +/- 3.2 micrograms ml-1 in serum from six additional patients receiving theophylline 9.1 +/- 3.4 micrograms ml-1 after adding 10 micrograms caffeine (NS), and 13.1 +/- 3.5 micrograms ml-1 after adding 10 micrograms 1,3-dimethyluric acid (p less than 0.001). We conclude that (a) the results obtained by the NIIA method are more variable and consistently higher than those obtained by the HPLC method and (b) 1,3-dimethyluric acid (a caffeine and theophylline metabolite) is responsible for this overevaluation.

Adult↗
PubMed1986

Pharmacokinetic and pharmacodynamic interactions between nifedipine and propranolol or betaxolol.

Pharmacokinetic and pharmacodynamic interactions between nifedipine and two beta-blocking agents were investigated. Eighty mg propranolol twice daily, and 20 mg betaxolol once daily, were randomly administered orally to six young healthy male volunteers, either singly for four days, or combined with nifedipine for the two subsequent days. Nifedipine had similar effects on the pharmacodynamics of both drugs. Nifedipine significantly enhanced propranolol bioavailability and Cmax, but reduced its tmax, in three out of six subjects who were also good absorbers of beta-blockers when taken alone. These effects might be due to enhanced intestinal absorption and/or enhanced first-pass effect, induced by nifedipine.

Adrenergic beta-Antagonists↗
PubMed1984

Family planning among a group of coloured women.

Two-hundred-and-fifty Coloured women were interviewed at family planning and antenatal clinics in an effort to assess the type of person who practices family planning and to determine possible ways of reaching those who do not. The study shows a definite tendency towards the small family ideal and children are seen as an expense rather than as a source of income. Forty-two per cent of the sample had either never used family planning methods or had done so only after their third child was born. Sixty-seven per cent indicated lack of knowledge or fears resulting therefrom as the reason for delaying family planning. Of the antenatal patients interviewed, 69% said their pregnancies were unplanned. This seems to indicate the need for an intensified drive to educate and motivate people, especially teenagers, to plan their families.

Adult↗
PubMed1983

[Ketoprofen-aspirin interaction].

Eighteen patients with chronic inflammatory joint disease were treated for two successive five day sequences, in a double blind crossover study, with 300 mg per day ketoprofen given alone or combined with 1,500 mg aspirin. Bioavailability and pharmacokinetics of total serum ketoprofen studied in eight patients did not appear to be significantly modified by addition of aspirin. Measurements of Ritchie's articular index and Lee's functional index demonstrated that ketoprofen was clinically as effective when given alone as in association with aspirin. Measurement of the sedimentation rate by the sigma ESR technique showed that aspirin produced a marked reduction of the antiinflammatory biological activity of ketoprofen which did not however reach statistical significance. This study of interactions between ketoprofen and aspirin shows that it is useless and perhaps harmful to combine the two medications.

Aspirin↗
PubMed1983

Pharmacokinetics in man of acebutolol and hydrochlorothiazide as single agents and in combination.

The pharmacokinetics of acebutolol and hydrochlorothiazide (HCT) alone or in combination were studied in 12 healthy subjects in a cross over study. Acebutolol and diacetolol (the main metabolite) in plasma and urine were determined by HPLC and hydrochlorothiazide by GLC. The main pharmacokinetic parameters of acebutolol did not differ significantly: AUC 4492 +/- 272 micrograms l-1h given alone versus 4118 +/- 354 micrograms l-1h with HCT, half-life (7,69 +/- 0,32 h vs 8,10 +/- 0,72 h) and renal clearance (13,1 +/- 0,5 lh-1 vs 13,8 +/- 0,9 lh-1), respectively. There was no difference in diacetolol pharmacokinetics. HCT values were not significantly different: AUC 784 +/- 48 micrograms l-1h given alone and 720 +/- 42 micrograms l-1h with acebutolol, t 1/2 (4,79 +/- 0,37 h vs 4,73 +/- 0,43 h). The renal clearance was slightly higher when HCT was given with acebutolol (26,2 +/- 2,6 vs 20,3 +/- 2,1 lh-1, p less than 0,05). This increase, observed during the first four hours, was probably due to competition between the drugs for binding to red blood cells.

Acebutolol↗
PubMed1983

Pharmacokinetics of a sustained-release trimazosin tablet formulation.

Pharmacokinetics and bioavailability of a trimazosin sustained-release tablet (SRT) formulation (300 mg) were studied in healthy volunteers. In the first study of 12 subjects, the bioequivalence of trimazosin, 100 mg, in a standard tablet (ST) and in a capsule was demonstrated. After that, the bioavailability of one SRT (300 mg) was compared with that of the STs, (100 mg three times a day), in 19 subjects. Maximum plasma concentration (Cmax) after SRT (8.1 +/- 3.0 mg/L) was significantly lower than that observed after ST (13.5 +/- 2.3 mg/L), time to peak was strongly delayed by a factor 7, and the time when plasma concentrations were higher than half of Cmax (t Cmax/2) was longer (10.4 +/- 3.2 vs 2.3 +/- 0.6 hours, p less than 0.001). Bioavailability of the SRT (300 mg) as measured by the area under the curve (AUC00) was about 65% of the ST. At the seventh dose, after single daily doses of the SRT in 12 subjects, the mean Cmax values were not significantly higher than after the first dose (8.6 +/- 3.2 mg/L vs 7.7 +/- 2.2 mg/L), t Cmax/2 values were the same (10.4 hours), and the AUC0-24 hr was comparable to AUC00 calculated after the first dose. Steady-state plasma concentration of trimazosin was obtained rapidly. No accumulation of trimazosin or its metabolite occurred.

Adolescent↗
PubMed1983

Pharmacokinetics of ketoprofen in the elderly.

Pharmacokinetic constants of ketoprofen (Orodis, Profenid) were determined in 10 young adults (24.9 +/- 1.3 years) and seven elderly patients (86.3 +/- 2.4). Following oral administration of a 150 mg dose of ketoprofen, no difference in tmax was observed between the two groups. However, compared with younger subjects elderly patients showed a significant increase in t1/2,z (2.72 +/- 0.22 vs 1.77 +/- 0.16 h; P less than 0.01) and AUC (70.4 +/- 6.4 vs 29.13 +/- 2.02 mg l-1 h; P less than 0.001), a non-significant reduction of Vd/F per kg bodyweight (0.145 +/- 0.016 vs 0.213 +/- 0.028 l kg-1) and a decrease in total clearance CLT/F (0.037 +/- 0.002 vs 0.071 +/- 0.004 l h-1 kg-1, P less than 0.05). These results suggest that the glucuroconjugation of ketoprofen is slowed down by age.

Adult↗
PubMed1983

A pharmacokinetic study of acebutolol in aged subjects as compared to young subjects.

Pharmacokinetics of acebutolol have been studied in hypertensive aged patients (79.4 +/- 3.8 years) and in young healthy subjects (23.4 +/- 0.7 years) after intravenous (0.35 mg/kg bolus) and oral administration (400 mg). Acebutolol and diacetolol, the main metabolite, plasma levels were determined by high-pressure liquid chromatography. After intravenous administration, apparent volume of distribution (1.5 vs. 2.4 liter . kg-1, p less than 0.05) and total body clearance (6.2 vs. 8.8 ml . min-1 . kg-1, n.s.) of acebutolol are smaller in elderly than in young men. After oral administration, maximum plasma levels (28.03 vs. 9.68 micrograms . l-1 . kg-1) and area under the curve (163.1 vs. 57.5 micrograms . l-1 . h . kg-1) are significantly higher in aged patients than in young subjects (p less than 0.001). Acebutolol and diacetolol plasma half-lives increase in elderly patients (11.6 vs. 7.2 h and 14.8 vs. 12 h respectively). These results suggest a possible accumulation of acebutolol and diacetolol in elderly.

Acebutolol↗
PubMed1982

Antihypertensive effect of diacetolol in essential hypertension.

1 Diacetolol is the N-acetylated metabolite of acebutolol and possesses beta-adrenergic receptor blocking properties. 2 Its antihypertensive action was assessed in accordance with a double-blind randomised cross-over scheme in 17 patients with moderate essential hypertension previously well controlled with acebutolol. 3 Significant reductions in lying mean arterial blood pressure were observed with daily doses of 200 mg (- 9%), 400 mg (- 10%) and 800 mg (- 14%), and were associated with significant decreases in heart rate and plasma renin activity. 4 The diacetolol mean plasma level measured 8 to 10 h after drug ingestion was proportional to the dose (207 +/- 27, 394 +/- 63 and 823 +/- 135 ng/ml for respectively 200, 400 and 800 mg/day).

Acebutolol↗
PubMed1982

The beta-blocking effect of diacetolol in humans and its relationship to plasma levels.

The beta-blocking action of diacetolol was studied in six healthy subjects after oral administration of placebo, 200, 400, and 600 mg diacetol in random order by means of exercise tests. Diacetolol plasma levels were determined by the HPLC method. Drug administration had No significant influence on resting heart rate and resting systolic or diastolic blood pressure. The beta-adrenoreceptor blockade was expressed as percentage reduction of exercise heart rate (delta FC%). This value increased with the size of the dose. There was a linear relationship between delta FC% and log plasma levels of diacetolol for each subject, except one. Analysis of variance did not provide a common regression line for all subjects.

Acebutolol↗