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Biomedical subjects

V Blaton

Publications and source records attributed to V Blaton.

18 recordsLinked to original sources
PubMed1992

Two automated fully enzymatic assays for lipase activity in serum compared: positive interference from post-heparin lipase activity.

The fully enzymatic Wako and Ektachem assays for pancreatic lipase in serum were found to yield precise (especially Ektachem) and consistent results that were significantly correlated (r = 0.995). Less good concordance was found with the turbidimetric aca method, results being on several occasions above normal by Wako or Ektachem but within the reference limit by the aca. Supplementation of aca packs with colipase generally increased lipase activities measured by the aca in these samples, thereby improving the correlation with Wako and Ektachem. In vitro addition experiments documented that both Wako and Ektachem were relatively insensitive to common chemical interferences. However, post-heparin lipase activities produced a positive interference in both assays, resulting in seemingly increased lipase activities that were suggestive of pancreatic disease. Substituting sodium glycocholate (6 mmol/L) for deoxycholic acid largely eliminated this positive interference in the Wako assay. Because Ektachem reagents cannot be modified in this way, we added sodium glycocholate (2-12 mmol/L) to sera; however, this failed to dissipate the in vivo effect of heparin on the Ektachem results.

Autoanalysis↗
PubMed1991

Interstitial pneumonitis and pulmonary vasculitis in a patient taking an L-tryptophan preparation.

A case is presented of interstitial pneumonitis and pulmonary vasculitis ascribed to the ingestion of an L-tryptophan preparation. An unintended rechallenge supported the causal relationship. There was neither myalgia nor peripheral eosinophilia. Bronchoalveolar lavage fluid contained 12% eosinophils but few were present in the surgical lung biopsy specimen. Lung infiltrates receded after withdrawal of the drug and treatment with steroids. Dyspnoea and pulmonary hypertension persisted. Cyclophosphamide had no effect. Sclerodermiform skin lesions appeared as a late sequel. Chromatographic analysis of the L-tryptophan revealed no suspect impurities.

Aged↗
PubMed1987

Serum cholesterol during ketanserin and propranolol administration in hypertensive patients.

The effect of ketanserin and propranolol on the serum total cholesterol (TC), and high-density lipoprotein (HDL-C) and low-density lipoprotein (LDL-C) cholesterol was studied in hypertensive patients treated for 3 months. During ketanserin administration, LDL-C decreased, whereas HDL-C and the HDL-C/LDL-C ratio increased and no significant effect in serum total cholesterol occurred. During propranolol administration, no significant effect was observed on serum total cholesterol, HDL-C and LDL-C, but the ratio of HDL-C/LDL-C increased. Intergroup comparison showed a greater increase in HDL-C (p less than 0.05) and in the HDL-C/LDL-C ratio (p less than 0.01) in the ketanserin group as compared with the propranolol group.

Body Weight↗
PubMed1979

Influence of oral polyunsaturated and saturated phospholipid treatment on the lipid composition and fatty acid profile of chimpanzee lipoproteins.

The influence of treatment with polyunsaturated lecithin (EPL) and with saturated lecithin on the lipoprotein composition and fatty acid profile was investigated in 4 male chimpanzees. The animals were successively given 3 isocaloric diets containing the same amount of fat with a degree of saturation varying from 1 in the control diet to 0.2 in the diet enriched with polyunsaturated lecithin, to 4 in the diet enrich with saturated lecithin. The VLDL, LDL and HDL3 fractions were isolated by ultracentrifugal flotation; changes in their lipid and fatty acid composition were followed and their microviscosity was measured. The treatment with polyunsaturated lecithin increases the cholesterol esters and lysolecithin content in HDL3, presumably via activation of the enzyme LCAT. These modified HDL particles have a more fluid surface and a denser core and are susceptible to act as better cholesterol carriers. A complementary effect of this treatment is a decrease of the plasma triglycerides and VLDL concentration, an increase in the unsaturation ratio of the triglycerides which might take place via activation of triglyceride lipase. The saturated lecithin treatment increases the plasma VLDL and LDL concentrations and the triglyceride levels and increases mostly the saturation ratio of the cholesterol esters. These effects are likely to enhance the progression of atherosclerosis.

Administration, Oral↗
PubMed1978

A simple screening method for plasma lipids by thin-layer chromatography with flame ionization detection.

Thin-layer chromatography was carried out on glass rods coated with Silica gel (chromarod) and the fractions were detected with a flame ionization detector (FID). This system was applied to the fractionation and screening of plasma lipids. As the relative response of the flame ionization detector depends on the nature of the lipids, correction factors had to be introduced. These correction factors were derived from comparison of the results of the thin-layer chromatography with flame ionization detection with those obtained by conventional chemical analysis of the same sample. The coefficients of variation of the lipid profiles were comparable for both techniques. The absolute lipid concentration for the various fractions obtained by combination of the concentration of the total lipids with the relative lipid profile, correlate very well with the values obtained by conventional chemical analysis of the various lipids.

Cholesterol↗
PubMed1977

Characterization of baboon plasma high-density lipoproteins and of their major apoproteins.

Baboon high-density lipoproteins (HDL) were isolated by preparative ultracentrifugation between d = 1.063 and 1.215 g/mL. The HDL contains 48.8% protein and a lipid distribution similar to human HDL. The phospholipid distribution shows a low sphingomyelin value (5.9%), and the fatty acid composition of HDL is comparable to the human data except for the 18:1/18:2 ratio as a result of a higher 18:1 content in the CE and a lower 18:2 concentration in the PL. The major HDL apoproteins isolated on diethylaminoethyl-cellulose had a mobility on sodium dodecyl sulfate--polyacrylamide gel electrophoresis and a molecular weight and an amino acid composition similar to human apoA-I. However, the amino acid sequence of the first 30 residues of baboon apoA-I differed from the human apoprotein in residues 15 and 21. Treatment of apoA-I with carboxypeptidase A indicated a carboxyl-terminal sequence of Leu-Ser-Thr-Gln. Baboon apoHDL contained monomeric apoA-II with the mobility of monomeric human apoA-II and a molecular weight of 8500. The amino acid composition differed from the human apoA-II by the presence of arginine and by the absence of half-cystine and isoleucine. The circular dichroic spectra of apoA-I and apoA-II demonstrated a higher helicity compared to the human apoproteins. Recombination studies by microcalorimetry of apoHDL with dimyristoylphosphatidylcholine (DMPC) indicated similarities in the thermodynamic binding properties of the HDL apoproteins from man and baboon. The maximal-binding enthalpies of DMPC to apoHDL, apoA-I, and apoA-II were lower for the baboon than for the human apoprotein.

Amino Acids↗
PubMed1977

Phospholipid binding and self-association of the major apoprotein of human and baboon high-density lipoproteins.

The purpose of this study was to establish a relationship between self-association and phospholipid binding of the human and the baboon apoA-I protein. The enthalpy changes on binding dimyristoyl lecithin and lysolecithin to either the human or the baboon native apoA-I protein were measured in a microcalorimeter. An endothermal process, most pronounced for the human apoprotein, was observed at low phospholipid levels. At higher phospholipid to protein ratios the binding was exothermal. Gel filtration experiments on Sephadex G-200 showed that the native apoprotein of both species consists of dimers and tetramers. The baboon native apoA-I protein contained a higher amount of dimers. After preincubation of the apoA-I protein with lysolecithin, the enthalpy changes measured on subsequent binding of dimyristoyl lecithin were shifted towards more exothermal values compared to the curve for the native apoprotein. The amplitude of this shift corresponds to that of the endothermal process observed on binding dimyristoyl lecithin to the native apoprotein. This process was attributed to a phospholipid-induced disaggregation of the apoA-I protein. Gel filtration data showed a decreased extent of aggregation in the apoA-I protein preincubated with lysolecithin. This sample consisted exclusively of dimers. Ultracentrifugal flotation of the complexes formed between the apoA-I protein, and respectively dimyristoyl lecithin and sphingomyelin indicated that preincubation with lysolecithin increased the extent of complex formation. These results suggest that the dimeric form of the apoA-I protein possesses the highest affinity for phospholipids. Any dissociation of higher polymers enhances the phospholipid-binding capacity of the human and the baboon apoA-I protein.

Animals↗
PubMed1977

Analysis of the proteins in sweat and urine by agarose-gel isotachophoresis.

A sensitive and practical method is described for the analysis of the proteins contained in human sweat and urine which does not require pre-concentration of the sample. Technical details are provided of the agarose-gel isotachophoresis and the proteinograms of normal and pathological urine samples, as well as proteinograms of human sweat. The method can also be applied as an electro-concentration system in a field-strength gradient. By means of this electro-concentration system, and in combination with immunodiffusion against monospecific antisera, a detection limit of albumin of 50 ng/ml has been obtained.

Albumins↗
PubMed1977

Effects of suloctidil on lipid metabolism in experimental animals.

A novel potent vasoactive agent, 1-(4-isopropyl-thiophenyl)-2-n-octylaminopropanol (suloctidil, Sulocton), lowers excess of plasma cholesterol and tends to normalize the plasma hyperbetalipoproteinemia of Rhesus monkeys fed a high-cholesterol, high-fat diet. The drug shows an inhibitory effect on the cholesterol biosynthesis in rat liver homogenates.

Animals↗
PubMed1976

The nonhuman primates as models for studying human atherosclerosis: studies on the chimpanzee, the baboon and the rhesus macacus.

There is no dearth of experimental techniques for producing the hyperlipoproteinemia resulting in atherosclerotic complications and for myocardial infarction in the non human primates. Most of the recent experiments which have given information of great value have been studied with relatively expensive animals for a long period of time up to 6-7 years. It is evident that no animal model perfectly duplicates the human disease or satisfies all desirable requirements. The chimpanzees, representatives of the New World monkeys, have circulating plasma lipoproteins identical to man in composition as well as in function. The results reported above indicate that the compositional changes of chimpanzee plasma lipoproteins in response to dietary changes reflect the appearance of type II and type IV hyperlipoproteinemia similar to the human disease. Moreover, there are more indications about the existence of genotype II a in the chimpanzee, and also on the influence of stress on the plasma lipids, so that the developed intimal lesions similar to the human pathology are in this sense multifactorially influenced. From a phylogenetic point of view the chimpanzee is closer to man than any other non human primate. Furthermore, the chimpanzee lipoproteins are useful models for understanding the relationship between function and structure of the plasma lipoproteins in health and disease. Baboon and rhesus monkeys show similar results, but more differences to the human lipoproteins in health and disease were observed. At present it appears that the most useful models of human atherosclerosis are those induced in the non human primates, especially in the chimpanzee.

Animals↗
PubMedDate not supplied

Iron in granulocytes of nephrotic patients determined by Zeeman electrothermal atomic absorption spectrophotometry.

One of the major threats to patients undergoing maintenance hemodialysis is an increased susceptibility to infections caused by microorganisms, among which Yersinia or Listeria are frequently recovered. In patients receiving hemodialysis, iron overload owing to multiple transfusions plays an important role in the mechanisms underlying the susceptibility to bacterial infections, partially mediated by impaired neutrophil function. In order to assess the true role of iron at the cellular level, an AAS method was developed to measure the iron content of granulocytes. Iron levels in the granulocytes were determined in an apparently healthy population and in a population of iron-overloaded renal hemodialysis patients. Granulocytes were isolated by a method modified from Böyum. The analyses were performed using pyrocoated graphite tubes, and in one of the char steps, oxygen was used to facilitate ashing. The mean iron level found in the granulocytes from apparently normal persons was 4.07 fg/cell (n = 17) with a CV of 44%; the mean value for the dialysis patient group was 4.59 fg/cell (n = 8) with a CV of 37%. There was no significant difference between the two groups, p = 0.70.

Adult↗