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Biomedical subjects

F Schiele

Publications and source records attributed to F Schiele.

At least 91 records · Page 5Linked to original sources
PubMed1989

Serum mitochondrial aspartate aminotransferase activity: not useful as a marker of excessive alcohol consumption in an unselected population.

Using an immunochemical method, we measured the activity of the mitochondrial isoenzyme (mAST) of aspartate amino-transferase (EC 2.6.1.1, AST) in the serum of 687 subjects attending the Centre for Preventive Medicine for a health examination. The distributions of the activities were asymmetrical, with mean values of 1.8 U/L (SD 2.0) for men and 1.4 U/L (SD 1.6) for women. The average ratio of mitochondrial to total AST activity was 0.051 (range 0-0.42). In this unselected population we found no change in the mitochondrial activity or in the mitochondrial-to-total ratio attributable to alcohol consumption, even in subjects who consumed more than 88 g per day. Of 35 men with an alcohol consumption greater than 88 g/d, 19 had a serum gamma-glutamyltransferase activity of greater than or equal to 60 U/L, 17 had glutamate dehydrogenase values greater than or equal to 5 U/L, and only nine had an mAST activity greater than or equal to 3 U/L (values corresponding to the 80th percentiles of the total population). We conclude that the test is not particularly useful as a screening procedure in an unselected population under present-day conditions of measurement.

Adult↗
PubMed1988

gamma-Glutamyltransferase reference material: an example of international cooperation.

The different steps in the preparation of a certified reference material for gamma-glutamyltransferase are described. A preparation of pig kidney gamma-glutamyltransferase, partly hydrolyzed with papain, was prepared and lyophilized in a matrix containing bovine serum albumin. The between-ampoule variability of gamma-glutamyltransferase was estimated to be 0.6%. The predicted degradation at -20 degrees C is 0.00% per year. The certification procedure involved 15 participating laboratories. The certified gamma-glutamyltransferase catalytic concentration of the reconstituted material, using the IFCC proposed method, is 86.8 U/1 with a 0.95 confidence interval of +/- 2.1 U/1.

European Union↗
PubMed1988

Alanine aminopeptidase in serum: biological variations and reference limits.

We studied the effect of various factors on the biological variation of alanine aminopeptidase (AAP, EC 3.4.11.2) in serum in a population of 2178 apparently healthy subjects and in subjects taking specific drugs. To measure AAP, we used an automated assay, with alanyl-4-nitroanilide as substrate. AAP activity concentrations were significantly higher in males than in females in all age groups between 10 and 55 years. The highest mean AAP values were found for children between 10 and 14 years. In male heavy smokers, AAP values were 8% higher than in moderate or nonsmokers (P less than 0.001); in females, this effect was less pronounced. AAP concentrations were higher in subjects consuming over 44 g of ethanol a day than in those consuming less (P less than 0.01 for men, P less than 0.05 for women). The use of oral contraceptives increased AAP values by 12% (P less than 0.001). Hypolipidemic drugs caused lower values for AAP in men (P less than 0.001). Subjects showing induction of gamma-glutamyltransferase (EC 2.3.2.2) by anticonvulsant drugs had also higher AAP activities (by 23%). Taking these data into account, we established reference limits for AAP in serum.

Adolescent↗
PubMed1988

[Exertion-induced parameters of left ventricular function in patients with chronic cardiac insufficiency. An isotope study].

Exercise-induced changes in haemodynamic values were studied by radionuclide ventriculography in 21 patients with permanent systolic dysfunction (15 with non-obstructive cardiomyopathy and 6 with ischaemic heart disease). The results were compared with those obtained in 8 control subjects with normal heart. In healthy subjects, during exercise the ejection fraction increased due to constant diminution of the end-systolic volume; the end-diastolic volume and the systolic ejection volume did not significantly vary; the cardiac output augmented only because of the accelerated heart rate. In patients with permanent left ventricular dysfunction, the ejection fraction remained unchanged during exercise, whereas the end-systolic volume increased significantly. Yet the systolic ejection volume increased due to a rise in end-diastolic volume. Heart rate and cardiac index increased, but not as much as in normal subjects. There was a close correlation between changes in end-diastolic and end-systolic volumes. It was the relative importance of changes in these two ventricular volumes that determined the direction and amplitude of variations in ejection fraction. It is concluded that in patients with permanent left ventricular dysfunction: (1) the end-systolic volume increases during exercise, thus betraying a worsening of the systolic dysfunction; (2) however, the systolic ejection volume is maintained or increases due to an increase in end-diastolic volume; (3) the changes in ejection fraction observed during exercise are of little value to characterize the modifications that occur in left ventricular work performance.

Adult↗
PubMed1988

[Application of bidimensional electrophoresis in the determination of genetic variants].

Study of the polymorphism of human plasma proteins presents a major advantage in clinical biology to discover abnormal or rare forms, associated with risks or involved with well-specified pathological conditions. If this polymorphism corresponds to structural differences causing a variation of the isoelectric point (Ip) or the molecular weight, it is easily visualized with bidimensional electrophoresis, starting with a few microliters of plasma. On a single mapping per patient, we were able to establish the frequency of various isoforms of Gc globulin, transferrin, haptoglobin, alpha-1-antitrypsin and apolipoproteins E as well as A-IV, in a Lorraine population consulting for a health check-up. This method has already enabled us to demonstrate the effect of polymorphic apolipoproteins on the cholesterol and triglycerides level: patients carrying the epsilon 2 allele of the Apo E, have a mean cholesterol level which is lower than that of the carriers of allele epsilon 3. Patients carrying allele epsilon 4 have the highest mean cholesterol level.

Blood Proteins↗
PubMed1988

Total, tartrate-resistant, and tartrate-inhibited acid phosphatases in serum: biological variations and reference limits.

We studied several factors affecting biological variation in serum acid phosphatases in a population of 1195 apparently healthy subjects four years old or older. We assayed total acid phosphatase activities in the presence of a transphosphorylating agent and using alpha-naphthyl phosphate as substrate. The main factors modifying total and tartrate-resistant acid phosphatases activities in serum are similar to those observed for total and bone alkaline phosphatases activities: age, sex, and hormonal state (puberty or menopause). The tartrate-inhibited acid phosphatase activity is, however, independent of biological variations. Finally, we propose reference limits for total, tartrate-resistant, and tartrate-inhibited acid phosphatases in serum.

Acid Phosphatase↗
PubMed1987

Production and certification of an enzyme reference material for gamma-glutamyltransferase (CRM 319). Part 1: Preparation and characterization.

We have produced a batch of lyophilized gamma-glutamyltransferase as enzyme reference material. The "light" enzyme form was purified from pig kidney to a relatively high specific activity (120 kU/g) and was essentially free of contaminating enzymes. The partly purified gamma-glutamyltransferase, lyophilized in a matrix containing bovine serum albumin (Fraction V, 60 g/L), yielded a batch of 4000 ampules and was stored at -20 degrees C. The vial-to-vial variability with respect to the catalytic concentration of the final product (CV 0.6%) and its stability (predicted loss of activity at -20 degrees C was less than 0.01% per year) were considered sufficient to allow the use of this preparation for a certification procedure. The behavior of the reference material in comparison with human serum samples was evaluated three ways: (a) by kinetic characteristics, (b) by the ratio of activities for duplicate determinations by different methods, and (c) by use of the reference material to convert values obtained by various methodologies to those by the IFCC proposed method. The material appeared to be commutable for the two methods studied. The difference in the ratios obtained for patients' samples and reference material was less than +/- 5%, and the recalculated values for patients' samples as determined with the reference material differed from values determined by the IFCC method by no more than 4.8%.

Animals↗
PubMed1987

Production and certification of an enzyme reference material for gamma-glutamyltransferase (CRM 319). Part 2: Certification campaign.

We describe the process of certification for a gamma-glutamyltransferase reference material (CRM no. 319). Fifteen laboratories participated to this interlaboratory evaluation. All steps of the measurements were controlled in an effort to locate potential sources of variations. In particular, the exclusion of some data was strictly documented or justified by the non-observance of the IFCC method and (or) discrepancies in instrumentation, reconstitution of the lyophilized samples, or measurement technique. Inaccuracy in the reconstitution of the lyophilized material was +/- 0.68%, and the molar absorptivity of the 5-amino-2-nitrobenzoate reported by each laboratory was within +/- 2% limits of the value reported by the IFCC. Calculated from the sets of accepted results, the total CV among samples was 2.6% and the overall CV was 3.2%. Within-day and between-day CVs were 1.1% and 1.4%, respectively. The greatest variation for a single component was the between-laboratory variability (CV 3.1%); the within-laboratory CV, including the day effect, was 1.8%. Finally, the certified value for the catalytic concentration of this enzyme in the reconstituted lyophilized reference material was 86.8 U/L with an uncertainty of +/- 2.1 U/L (0.95 confidence interval). The uncertainty appeared to be compatible with the end-use of this reference material.

Catalysis↗
PubMed1987

[Absence of a relationship between the prevalence of markers for hepatitis B virus and the moderate consumption of alcohol].

The prevalence of 3 serological markers of hepatitis B virus was studied in a sample population of 481 men between the ages of 40 and 60 examined in the course of a routine medical checkup, whose acknowledged intake of pure alcohol was under 120 g per day. No statistically significant relationship was found between the frequency of the markers (HBs antigen, anti-HBs and anti-HBc antibodies) and the level of acknowledged alcohol consumption. The frequencies of the major potential risk factors in hepatitis B virus infection were similar among patients claiming to drink less than 20 g per day and those claiming an intake of between 20 and 80 g daily. Finally, the activities of some of the plasma enzymes most frequent in hepatology increased in a statistically significant way with acknowledged consumption of alcohol--this, in the absence of any contact with hepatitis B virus. No relationship was shown between enzyme levels and the presence--or absence--of hepatitis B markers, whatever the acknowledged alcohol consumption.

Adult↗
PubMed1986

[Epidemiologic study of atopic environment in Lorraine].

An epidemiology study on atopy was performed in a Center of Preventive Medicine, in 505 children aged from 4 to 14 years old, in good health, in consultation with their parents. The clinical atopy was evaluated by a questionnaire inquiring about atopic dermatitis, hay fever, infantile asthma, previous recurrent infections, breast or bottle feeding. Total serum IgE were dosed (Phadezym) and pricks performed to mites and pollens. The clinical atopy is diagnosed in 14.46% of cases (atopic dermatitis: 10.28%--asthma: 3.76%--hay fever: 2/98%). Pricks are positive in 14.85% of cases (mites: 11.48%--pollen: 99.11%--both: 5.74%). The cutaneous sensibility is observed in 32.8% of cases with clinical atopy, 12.5% of other children. The total IgE are very variable and does not correlate with a normal distribution. This allows definition of the quartile below which 90% of the sample is to be found: 474 kUI/l. There is a highly significant relation (p 0.001) between clinical atopy and positive pricks to airborne allergens, clinical atopy and raised alone 474 kUI/l, positive pricks and IgE of more than 474 kUI/l. There is a close relation between atopy and recurrent infections, raised IgE in children and paternal atopy, specific IgE in children and maternal atopy. It appears also that breast feeding is a risk factor for raised IgE in children when the mothers are not atopic, which is somewhat unexpected. Investigation of an atopic terrain may be performed through skin tests or an assay of seric IgE, which seem to be closely comparable.

Adolescent↗
PubMed1986

[Prevalence of viral hepatitis B markers in a sample population seen at a center of preventive medicine].

The frequency of hepatitis B markers was studied on 992 subjects attending health examinations in Preventive Medicine Center of Vandoeuvre-les-Nancy. The aim of this work was to precise some epidemiological factors in this population. Results of this study have specified that 9% of individuals have shown signs of past infection and 0.3% of subjects having at least one marker were positive for the HBs-antigen. Most results agree with the literature and markers prevalence was found associated with some parameters as age and ethnic origin.

Adolescent↗
PubMed1985

Total cholinesterase in plasma: biological variations and reference limits.

Factors affecting biological variation in total cholinesterase activity in plasma were studied in a population of 3372 apparently healthy subjects at least four years old. Determination of the dibucaine number, after inhibition of the activity by dibucaine, made it possible to specify the contributions of genetic and physiological characteristics to variations in the total activities by using a statistical method of segmentation. The main factors modifying plasma cholinesterase activity in males are genetic status (dibucaine number) and degree of overweight (subscapular skinfold). In females, hormonal status (puberty or menopause), genetic status (dibucaine number), and the use of oral contraceptives are the factors mainly responsible for the variations of plasma cholinesterase activity. These data allow us to propose reference limits for total plasma cholinesterase.

Adolescent↗
PubMed1983

Total bone and liver alkaline phosphatases in plasma: biological variations and reference limits.

We have studied factors affecting biological variation in total plasma alkaline phosphatase in a population of 32 329 apparently healthy subjects four years old or older. Quantification of the bone and liver isoenzymes after thermal denaturation made it possible to specify the contributions of each isoenzyme to variations in the total activities. The main factors that modify plasma alkaline phosphatase activity are age, sex, hormonal state (puberty or menopause), and morphometric parameters (height, body weight, or degree of overweight). The bone isoenzyme is mainly responsible for the variations associated with age, sex, and puberty and to some extent with the menopause. Activity of the liver isoenzyme was also altered at the menopause and by certain drugs, such as oral contraceptives and blood-lipid-lowering agents. These data allow us to propose reference limits for total plasma, bone, and liver alkaline phosphatases according to age and sex.

Adolescent↗
PubMed1981

Measurement of plasma gamma-glutamyltransferase in clinical chemistry: kinetic basis and standardisation propositions.

The conditions for the measurement of gamma-glutamyltransferase (EC 2.3.2.2) activity of human plasma were studied at 30 degrees C using the kinetic technique of Szasz [3]. The optimum pH in Tris (hydroxymethylaminomethane) buffer and 2-amino-2-methyl-1.3-propanediol at a concentration of 100 mmol/1 are 8.0 and 8.1. The kinetic characteristics of human plasma gamma-glutamyltransferase were studied using gamma-L-glutamyl p-nitroanilide and its carboxyl derivative as donor substrates. Glycylglycine was chosen as the best acceptor of the gamma-glutamyl radical. Under these conditions, we have shown that the inhibition by the donor substrate was more important at acidic pH and vanished at alkaline pH. This inhibition was obviously related to the presence of the acceptor, but did not vary with glycylglycine concentration. At pH 8.0, by increasing the acceptor concentration some competition occurs at the donor binding site, as reported by other authors in relation to the known ping-pong bi-bi enzyme mechanism for the gamma-glutamyltransferase. Some displacement of donor substrate by increasing amounts of acceptor substrate could be observed at all pH values we studied. However, the influence of glycylglycine on the enzyme's maximum velocity and affinity for the donor substrate was also pH dependent. Studying the kinetic characteristics of the enzyme as a function of the pH suggests that the enzyme works with more than one active site at pH 7.5-8.0. Based on the results of this study, we propose measurement conditions for gamma-glutamyltransferase at 30 degrees C in routine clinical chemistry without preference in the choice of substrate.

1-Carboxyglutamic Acid↗
PubMed1981

Some kinetic properties of gamma-glutamyltransferase from rabbit liver.

gamma-Glutamyltransferase ((5-glutamyl)-peptide: amino-acid 5-glutamyltransferase, EC 2.3.2.2) of rabbit liver (detergent form) was purified 1100-fold in order to study its kinetic properties. Kinetic studies were conducted from pH 6.0 to 12.0 in the absence and presence of the acceptor substrate glycylglycine using gamma-glutamyl-3-carboxy-4-nitroanilide as the donor. The existence of more than one binding site for both donor and acceptor is postulated on kinetic evidence such as donor substrate activation, donor substrate inhibition and acceptor substrate activation. Homotropic interaction is also observed, in the form of negative cooperativity, in donor substrate binding, in the absence of acceptor at pH less than 9.0 and positive cooperativity (n = 2), in the absence or presence of acceptor at pH greater than 9.0. Hydrolase reaction reaches a maximum of activity at pH 10 (pK 8.6). Transferase activity under conditions of maximal velocity is maximal at pH 9.0 (pK 7.1). The ratio of transferase activity/hydrolase activity is maximal at pH 7.0-7.5. At low donor substrate concentrations, maximal activity is attained at pH 7.5.

1-Carboxyglutamic Acid↗
PubMed1980

Automated quantification of bone and liver alkaline phosphatase isoenzymes of human serum.

Coupling two Technicon AAII samplers synchronised at 50 per hour with a 2 : 1 sample to wash ratio, sera are denatured and collected automatically. The incubation is done in continuous flow by passage through a U device made of large metallic needles soaked in a water bath at 60 +/- 0.1 degree C. This allows a very quick temperature equilibration and a very reproducible incubation time of 35 sec. Initial and residual activities of alkaline phosphatase (ALP: EC 3.1.3.1) are measured on a Rotochem II (Aminco) with the procedure recommended by the Société Française de Biologie Clinique (SFBC). For a mixture of bone and liver ALP, the initial rate constant of heat denaturation Kapp = (A X Kb) + (B X Kl), where A and B are the fractions of each isoenzyme in the mixture, and Kb and Kl the rate constants for bone (b) and liver (l) experimentally determined as 1.8 min-1 and 0.45 min-1 respectively. An equation was derived which converts the percent residual activity to a percentage of bone and liver isoenzyme: % bone ALP = 183--2.38 X % residual activity. This automated method was applied to 2700 people of both sexes from 4 to 100 years old.

Adolescent↗