Biomedical subjects
Publications and source records attributed to L Muller.
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A nondestructive method has been developed for rapid analysis of lipid content of membrane extracts based on high field proton NMR spectroscopy. Lipid extraction is done by stepwise sonication of purified membranes into chloroform:methanol:water mixtures, and 1H spectra are recorded at 35 degrees C on final preparations consisting of at least 1 mg dried lipid solubilized in 2:1 CD3OD:CDCl3. Spectral peaks of lipid mixtures are assigned to lipid classes using a data base of standard lipid characteristic resonances derived from purified single membrane lipids and known mixtures of them. Peak intensities of characteristic peaks yield ratios of various lipids such as cholesterol:phospholipid and phosphatidylcholine:phosphatidylethanolamine, degree of unsaturation, average acyl chain length, total glycerol lipid content, and presence or absence of particular lipids, such as glycolipids or lysolipids. This procedure of membrane lipid analysis has been verified using known mixtures of purified standard lipids.
The authors record the most frequent electrocardiographic anomalies in children and teenagers. The course of the frequency of ectopic rhythms and right focal blocks is studied. Variations in the duration and axis of the electrocardiographic complexes are described in terms of age and sex, and reference figures are presented.
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The effects of low-level cadmium (Cd) administration to rats on animal health, liver and kidney thiols, metallothionein, and glutathione reductase (GSSG reductase) and their modulation by cysteine (as a possible protector) and diethyl maleate (as a possible potentiator) have been investigated. Male Sprague-Dawley rats were treated with sodium or Cd acetate (25 micrograms Cd/kg) orally five times a week for 6 weeks. A second group of animals received cysteine (500 mg/kg; po) before each gavage while a third group received diethyl maleate (DEM) (0.85 mg/kg; ip) in addition to sodium or Cd acetate. When rats were treated with cadmium alone neither weight gain nor serum parameters indicative of hepato- or nephro-toxicity were affected. However, acid-soluble thiols, primarily glutathione, were decreased by about 25% in liver only. A tendency to a decrease in hepatic protein thiols was also noted. No changes were observed for hepatic or renal metallothionein in response to this low level of cadmium administration alone or in combination with the other treatments. Animals receiving cysteine, either alone or with cadmium, showed decreased body weight gain, but no change in serum parameters. Acid-soluble thiols in liver were lower in cysteine-treated rats (24%) and cysteine + Cd (33%) while kidney thiols were unaffected. Administration of DEM alone or with Cd did not cause any alteration in body weight gain. When given DEM + Cd, however, an increase in serum bilirubin was observed, which suggests interference with hepatobiliary function. Acid-soluble thiols were decreased by DEM alone (45%) and DEM + Cd (51%) in liver while renal thiols showed no change. Our data indicate that low-level Cd gavage decreases hepatic cellular thiols but not those of kidney. Cysteine gavage does not protect from the Cd-related effect. Indeed, cysteine itself was found to reduce acid-soluble thiols under the experimental conditions. This was observed only in liver, as was the decrease in thiols due to DEM treatment. DEM administration together with Cd resulted in signs of liver toxicity. There is no indication that inhibition of GSSG reductase by Cd might be involved in the thiol-decreasing effect of short-term repeated low-level gavage of Cd to rats.
The results of studies examining the effectiveness of tactile stimulation as a form of sensory enrichment for infants and young children were analyzed by the use of recently developed quantitative methods that treat research synthesis as a unique type of scientific inquiry. Nineteen studies meeting certain predetermined criteria were included in the review. The 19 studies contain 103 statistical hypothesis tests that evaluated the effectiveness of tactile stimulation programs. Analysis of these tests, based on the calculation of effect sizes, revealed that subjects receiving some form of controlled tactile stimulation performed better on a variety of dependent measures than subjects not receiving intervention. Larger treatment effects were associated with pre-experimental designs, and also with studies in which the internal validity was rated as poor. Several other study characteristics, such as how the subjects were assigned to conditions and how the dependent measure was recorded, were related to study outcome as measured by effect size. The results indicate that an accurate interpretation of tactile stimulation studies cannot be made without consideration of specific design variables and study characteristics.
Currently, practitioners are confronted with the biological problems of migrants and have at their disposal for comparison only reference values established on autochtonal populations. Can these figures be used? From the population living in North-East France, we have established five groups of individuals originating from definite geographical areas: Italy, Iberian peninsula, Northern Europe and Central Europe, North Africa, Near and Middle East, in addition to the French. By means of a multiple regression analysis, we looked for and effect due to the geographical origin of the patients in order to describe specific characteristics of cardiovascular and morphometric examinations and read them accordingly. This study demonstrates the existence of several population groups: patients from the Near and Middle East and North Africa; immigrants from Southern Europe and Northern and Central Europe natives.
We measured concentrations of 5 alpha-androstane-3 alpha,17 beta-diol (Ad) and 5 beta-androstane-3 alpha,17 beta-diol (beta-Ad) in urine by specific capillary gas chromatography-mass spectrometry, with [16,16,17 alpha-2H3]-5 alpha-androstane-3 alpha,17 beta-diol as the internal standard. Comparison of the so-derived reference intervals for Ad and beta-Ad in men and women with those previously published indicates a significant positive bias for many of the previous assays in comparison with our procedure. Both Ad and beta-Ad have a pronounced diurnal rhythm, with maximum excretion in the interval 2300-0700 hours. Concentrations of Ad and beta-Ad were significantly correlated (r = 0.786, p less than 0.001), but the ratio of Ad to beta-Ad was not correlated to that for androsterone to etiocholanolone, the major 5 alpha and 5 beta metabolites of androgens in urine.
Tuberous sclerosis is an autosomal dominant disease with variable expression. The initial manifestations have been reported at varying stages postnatally, but little is known about the fetal age at which the disease may be detected. The antenatal ultrasonographic features in 2 affected fetuses, at 40 and 26 weeks respectively, are reported. The second case appears unique because of the early fetal involvement and the abnormally large brain tumour.
Common electrocardiographic manifestations (CEM) are predictors of ischemic heart disease (IHD). If precursors of the disease, their risk factors should be similar to those of IHD. This hypothesis has been assessed on results of multiphasic screening recorded in 1976 and 1981, in 1,347 45-65 year old men. Risk factors are social class (blue collar relative risk rr = 2.3), physical activity at work (sedentariness rr = 2.4), systolic blood pressure, no beer consumption and blood urea nitrogen with an exponential risk curve. Cholesterolemia, smoking, diabetes mellitus, overweight and uricemia are not predictors of CEM incidence within 5 years. These results support the idea that CEM are partially asymptomatic expression of IHD; they also have another significance. Subgroups should be individualized and analysis yielded on larger samples. Correlation analysis has been performed between IHD mortality and beer consumption on basis of French counties. A positive correlation (r = 62, p less than 0.01) is opposed to individual results.
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Resistance of faecal Escherichia coli to ampicillin, tetracycline, sulphamethoxazole and gentamicin was studied in patients admitted to seven different departments in two hospitals. The resistance of ampicillin, tetracycline and sulphamethoxazole in the seven patient groups was 27-57%, 26-56% and 35-63%, respectively. Resistance to gentamicin was found in only one department. An E. coli flora predominantly resistant to ampicillin, tetracycline or sulphamethoxazole (greater than 50% of the E. coli strains in a faecal sample resistant) was found in 10-38%, 4-30% and 21-35% of the samples. A cross-sectional study focusing on the influence of the use of antimicrobial agents on the occurrence of resistant strains revealed a positive correlation between the annual turnover of broad-spectrum penicillins in various departments and the occurrence of predominantly ampicillin-resistant E. coli strains in these departments.
Faecal carriage rates for aerobic gram-negative bacilli and for antibiotic-resistant Escherichia coli were determined in samples of the Dutch urban population. Of the 741 people studied, 64 were under 1 year old (infants), 53 were 1-5 years old, and there were approximately 200 in each of the age-ranges 6-17 years, 18-49 years and 50-80 years. Carriage rates of E. coli were similar (87-93%) in all age groups, but Klebsiella and Enterobacter species were found more often in specimens from infants and young children than in those from older people. E. coli strains resistant to tetracycline, ampicillin, or sulphamethoxazole or to any one or more of them were detected in 42%, 26%, 46% and 66% respectively of the specimens found to contain E. coli. The corresponding figures for the finding of E. coli populations that were predominantly resistant to tetracycline, ampicillin or sulphamethoxazole were 12%, 6% and 20%. The frequency of resistance to any of these drugs was not related to age or sex of the subjects. All E. coli isolates were sensitive to gentamicin. Among the 577 subjects aged 6-80 years from whose samples E. coli was isolated were 19 who had taken antibacterial drugs in the previous 30 days and 11 who were involved in cattle farming; carriage rates for tetracycline-resistant and sulphonamide-resistant E. coli were significantly higher among these 30 than in the other 547.
A microhematocrit concentration method (MH) for immediate diagnosis of Chagas' disease during the acute stage or in congenital cases was standardized. Parasitemia as low as 1,000 parasites per ml was detected, after centrifugation of six 50-microliters capillary tubes, by 10-min microscopic observation of each buffy coat spread between slide and cover glass. Operator's time was reduced by at least one-third when compared with a fresh blood observation (FB). In 12 of the 15 patients studied, diagnosis was performed in 4.9 +/- 3.08 min with MH, whereas 27.0 +/- 12.1 min were necessary when FB was used. In the three remaining patients whose FB results were negative, MH became positive after 13, 16, and 40 min. In our experience, FB proved to be more sensitive than previously reported. Suckling mouse inoculation also proved to be sensitive but, as in xenodiagnosis and in hemoculture, the delay in getting the final result was a limiting factor.
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