Relations between reported alcohol consumption and certain biological variables in an "unselected" population

We looked for variables that could serve as indexes of alcohol consumption. We tested iron, gamma-glutamyltransferase, mean erythrocyte volume, mean erythrocyte hemoglobin concentration, urea, uric acid, and alanine aminotransferase, among others, in an unselected population of men, and by principal components analysis we singled out the correlation between the two enzymes and the two hematologic values. On the other hand, calculation of the coefficients of correlation between the total amount of alcohol consumed and the 10 variables studied, together with multiple regression analysis, showed that the three variables that correlated most significantly with alcohol consumption were gamma-glutamyltransferase, mean erythrocyte volume, and the use of tobacco. Critical evaluation of the results leads us to conclude that still more discriminative biological indices msut be sought and that the use of psychosocial data is also desirable.

Relations between reported alcohol consumption and certain biological variables in an "unselected" population

We looked for variables that could serve as indexes of alcohol consumption. We tested iron, gamma-glutamyltransferase, mean erythrocyte volume, mean erythrocyte hemoglobin concentration, urea, uric acid, and alanine aminotransferase, among others, in an unselected population of men, and by principal components analysis we singled out the correlation between the two enzymes and the two hematologic values. On the other hand, calculation of the coefficients of correlation between the total amount of alcohol consumed and the 10 variables studied, together with multiple regression analysis, showed that the three variables that correlated most significantly with alcohol consumption were gamma-glutamyltransferase, mean erythrocyte volume, and the use of tobacco. Critical evaluation of the results leads us to conclude that still more discriminative biological indices msut be sought and that the use of psychosocial data is also desirable.

Factors affecting the concentration of triacylglycerols (triglycerides in plasma: reference values for adults

We studied factors influencing concentrations of triglycerides in the blood of a presumably healthy population of about 9000 persons. Using multi-dimensional analysis, we show, in addition to various related to sex and age, the relation between triglycerides and uric acid, overweight, arterial blood pressure, use of oral contraceptives (in women), consumption of alcohol and tobacco, and lack of physical exercise. These factors were classified as a function of their discriminative power by the statistical method of segmentation. We thus chose the following factors as criteria for exclusion from a reference population for the values of triglycerides in blood: in men 20 to 39 years old, overweight more than 90%; in men 40 to 59 years old, overweight of more than 115%, consumption of more than half a liter of wine per day or of more than 11 cigarettes, use of medicines, and a blood uric acid exceeding 420 mumol/L; in women 20 to 39 years old, contraceptives and overweight; in women 40 to 59 years old, overweight or more than 130% and the intake of medicines. At the 97.5th percentile of the reference population as compared with a non-selected population, the values were 80% less for men 20 to 39 years old, 95% less for men 40 to 59 years old, and only 26 to 30% less for women 20 to 59 years old.

Factors affecting the concentration of triacylglycerols (triglycerides in plasma: reference values for adults

We studied factors influencing concentrations of triglycerides in the blood of a presumably healthy population of about 9000 persons. Using multi-dimensional analysis, we show, in addition to various related to sex and age, the relation between triglycerides and uric acid, overweight, arterial blood pressure, use of oral contraceptives (in women), consumption of alcohol and tobacco, and lack of physical exercise. These factors were classified as a function of their discriminative power by the statistical method of segmentation. We thus chose the following factors as criteria for exclusion from a reference population for the values of triglycerides in blood: in men 20 to 39 years old, overweight more than 90%; in men 40 to 59 years old, overweight of more than 115%, consumption of more than half a liter of wine per day or of more than 11 cigarettes, use of medicines, and a blood uric acid exceeding 420 mumol/L; in women 20 to 39 years old, contraceptives and overweight; in women 40 to 59 years old, overweight or more than 130% and the intake of medicines. At the 97.5th percentile of the reference population as compared with a non-selected population, the values were 80% less for men 20 to 39 years old, 95% less for men 40 to 59 years old, and only 26 to 30% less for women 20 to 59 years old.

The effect of dietary sulfur-containing amino acids on the activity of drug-metabolizing enzymes in rat-liver microsomes

Male Wistar rats were fed either a balanced diet whose protein source was a mixture of amino acids (diet 1), or a similar diet which differed only in having 48% less the quantity of the sulfur-containing amino acids methionine and cystine (diet 2). The diets were given either continuously for 1 month or for 15 days after a protein-free diet. Both diets 1 and 2 permitted good growth of rats and relatively stable microsomal protein content. Protein depletion decreased the total proteins, total phospholipids, and cytochrome P-450 content, and it strongly increased UDP-glucuronosyltransferase activity in rat-liver microsomes. Repletion with diet 1 restored those values, to the level found in control rats. However, diet 2, given continuously induced an increase in UDP-glucuronosyltransferase activity and in the cytochrome P-450 concentration. Since high UDP-glucuronosyltransferase activity was related to lessened amounts of sulfur-containing amino acids in the diet, we discuss the possible effect of methionine and cystine on the regulation of glucuronoconjugation in relation to sulfoconjugation.

Drug interference in clinical chemistry: studies on ascorbic acid

The expert group "Drug Interference in Clinical Chemistry" of the Bureau of Reference, Directorate General for Research, Science and Education of the Commission of the European Communities, consisting of one participant of each member of the European Communities, presents this first report on the final results of its activities. Within the framework of a first stage basic program, the paper describes interferences of therapeutic and elevated doses of ascorbic acid on commonly used clinical chemical methods. This is the result of a bipartite study that was jointly planned, carried out and evaluated. Local and personal influences have been eliminated, as have variations due to methodology, measurement equipment and reagents, in order to be able to present distinct causal effects of ascorbic acid. No definite influence of ascorbic acid on analytical values for urea, cholesterol, calcium, protein, bilirubin, aspartate aminotransferase and alkaline phosphatase could be detected. At therapeutic concentrations, ascorbic acid distinctly interferes with the analysis of glucose, uric acid, creatinine and inorganic phosphate. The extent and direction of interferences vary, depending on the type of reaction, kit and apparatus. In some cases the influence of ascorbic acid results in severe disturbance of the analytical methods leading to useless values.

[Influence of oral contraceptive agents on the concentration of amino acids in leukocytes of supposedly healthy women (author's transl)]

The concentration of amino acids has been measured in leukocytes of women taking oral contraceptive agents and also in controls. These assays were made by means of ion exchange chromatography. The amino acid pool in leukocytes was found to be smaller in those patients taking the "pill". Each amino acid concentration decreased except for taurine and glutamine. Taurine represented 64.1 percent of the pool in treated women and only 23.5 percent in controls. Glutamine represented 9.5 percent of the pool in patients and 3.7 percent in controls.

Protein and enzyme release from human leukocytes: influence of phenothiazine derivatives

We studied the influence of chlorpromazine on the release of enzymes (beta-glucuronidase, EC 3.2.1.31; lactate dehydrogenase, EC 1.1.1.27; pyruvate kinase, 2.7.1.40) and proteins using human granulocytes isolated and maintained at 37 degrees C. Chlorpromazine had a biphasic effect on enzyme release and the inhibition of the glycolytic pathway could be demonstrated only at high concentrations of chlorpromazine, after one hour's incubation. The NAD+/NADH ratio was significantly perturbed at all the concentrations. This effect is time dependent. The action of 4 other phenothiazine derivatives made it possible to establish a relationship between their physico-chemical properties and protein release. The results are compared with those from other studies using other biological materials.

Influence of glucose and inhibitors of glycolysis on release of total proteins and enzymes from human leukocytes

We studied the influence of substrates and glycolysis inhibitors on the release of proteins and enzymes from human leukocytes. We show the relationship between metabolic level and percentage of enzyme release. Leukocyte kept alive in a nutrient-free bicarbonate medium liberate enzymes even though their metabolic state is satisfactory. The addition of glucose to themedium significantly decreases this phenomenon without affecting the energy level. Addition of glycolysis inhibitors increases it, reduces the energy level, and interferes with other metabolic pathways. The results are discussed and compared to those obtained by other authors using various cell models.

Gamma-glutamyltransferase activity in plasma: statistical distributions, individual variations, and reference intervals

Measurement of gamma-glutamyltransferase activity in plasma provides a useful index to liver function. Using as our study population those persons coming to the Center for Preventive Medicine, we described and measured the significance and importance of physiological and environmental variations. We established a classification for the variation factors. The three most important factors affecting this activity were drug intake, alcohol consumption, and excessive weight, followed by sex and age. We suggest a preliminary group of reference intervals for healthy subjects to be used in interpreting a laboratory test.

Gamma-glutamyltransferase activity in plasma: statistical distributions, individual variations, and reference intervals

Measurement of gamma-glutamyltransferase activity in plasma provides a useful index to liver function. Using as our study population those persons coming to the Center for Preventive Medicine, we described and measured the significance and importance of physiological and environmental variations. We established a classification for the variation factors. The three most important factors affecting this activity were drug intake, alcohol consumption, and excessive weight, followed by sex and age. We suggest a preliminary group of reference intervals for healthy subjects to be used in interpreting a laboratory test.

Comparison of procedures for extracting free amino acids from polymorphonuclear lekocytes

We studies five methods for extracting amino acids from human polymorphonuclear leukocytes. Both the use of cell lysis and of a deproteinizing agent interfere with quantitative determination of the amino acids, basic amino acids being the most sensitive to the extraction procedure. Among the methods used, disruption of the cells by freezing-thawing is the best method for extracting all the amino acids. Taurine is the only amino acid extracted in the same amount by all the methods studied, and it represents half of the intracellular pool.

Comparison of procedures for extracting free amino acids from polymorphonuclear lekocytes

We studies five methods for extracting amino acids from human polymorphonuclear leukocytes. Both the use of cell lysis and of a deproteinizing agent interfere with quantitative determination of the amino acids, basic amino acids being the most sensitive to the extraction procedure. Among the methods used, disruption of the cells by freezing-thawing is the best method for extracting all the amino acids. Taurine is the only amino acid extracted in the same amount by all the methods studied, and it represents half of the intracellular pool.

Quantitative determination of granulocytic amino acids in healthy men and women

The concentration of the amino acids has been determined in granulocytes from healthy men and women by chromatographic analysis on ion-exchanging resins. Except taurine, ornithine and aspartic acid, the concentrations of all the amino acids are greater in the cells isolated from women. The most variable amino acids are alanine, valine, metionine, isoleucine, leucine, tyrosine, phenylalanine, lysine and histidine. Taurine represents 50% of the pool determined from men, whereas for women it represents only 25%.

Ornithine carbamoyl transferase activity. Use of a bovine liver extract in quality control

To obtain a pure ornithine carbamoyltransferase for quality control in clinical chemistry, the authors compared human plasma and bovine liver ornithine carbamoyltransferase. The data show that the KM of both enzymes are similar (respectively 1.03 and 1.33 mmol when ornithine is used as substrate; 1.02 and 1.06 mmol with carbamyl phosphate). The following properties are shown to be equivalent: linearity of the enzymatic reaction, inhibition by higher substrate concentrations, and temperature denaturation. The similarities between the two enzymes indicate that bovine liver ornithine carbamoyltransferase can be used in clinical chemistry quality control.

Continuous in vivo measurement of creatine kinase variations in man during an exercise

In order to obtain information concerning the CPK turnover during exercise, we have elaborated a technique to measure its activity continuously in vivo. A colorimetric method has been adapted to total blood. CPK was measured continuously in 5 physically fit athletes exercised on an ergometric bicycle for 30 min. There was practically no increase in enzymatic activity. The starting level was very high, corresponding perhaps to a "permanent state of enzyme release"; the exercise was not hard enough because of the fitness of the athletes or the maximal increase did not occur immediately after the exercise.

Amino acid analysis by ion-exchange chromatography using a lithium elution gradient. Influence of methanol concentration and sample pH

The separation of amino acids has been achieved on a short column of Chromo-Beads C2 resin, with a lithium gradient-elution system. The analysis took 8 h. The separation of asparagine and glutamine from glutamic acid was highly dependent on the sample pH and on the methanol concentration in the first buffer of the gradient. The method has been applied to analysis of human plasma and granulocytes for amino acids.

Colorimetric measurement of ornithine carbamoyl transferase activity in plasma, and results for a supposedly healthy population

Determination of ornithine carbamoyl transferase (EC 2.1.3.3) activity in plasma is important for detection of liver diseases. The assay established in this paper has been made optimum. A blank is needed containing both substrates, carbamoyl phosphate and ornithine. We used a new colorimetric assay, based on a complex with a phosphoferric-antipyrine reagent and diacetyl monoxime, to measure the citrulline formed. The highly sensitive assay permits low activities to be determined accurately. Values for blood plasma from 425 supposedly healthy people, varied from 0 to 16 U/liter (95th percentile), and 27% of this population showed an activity of less than 2 mumol of citrulline formed per minute per liter, 2 U/liter being the limit of the method's sensitivity.

Aspartate aminotransferase and alanine aminotransferase activities in plasma: statistical distributions, individual variations, and reference values

The determination of frequency value (percentile limits) and the classification of the different variation factors allow us to define more and more homogeneous subpopulations as we use these factors for sorting. Using as our study population those persons coming to the Centre for Preventive Medicine, we were able to: (a) Describe and measure the significance and importance of physiological variations or of variations attributed to age--the latter largely related only to excessive weight, which it seems to us is often the case. (b) Establish a classification for variation factors; the recapitulatory table should be useful to clinical chemists in helping physicians interpret a laboratory test result that falls within the zone of incertitude. (c) Suggest a preliminary group of reference values for healthy subjects, to be used in interpreting a laboratory test in this way.