N-nitroso compounds, nitrite and pH in human fasting gastric juice.

Total N-nitroso compounds, ethyl acetate-extractable N-nitroso compounds and nitrite were measured in 146 samples of fasting gastric juice to investigate their relationship with pH. A positive correlation was found between pH and extractable N-nitroso compounds (r = 0.206, P < 0.02), whereas total N-nitroso compounds were pH-independent. It was inferred that pre-cancerous conditions associated with high gastric pH may be produced by an increase in the extractable N-nitroso compounds, which constitute only a small fraction of the total gastric N-nitroso compounds.

Individual free fatty acids and lactate uptake in the human heart during severe sepsis.

Coronary haemodynamics and myocardial metabolism of nonesterified fatty acids (NEFA) and lactate were studied in 11 patients with severe sepsis, and compared to 10 control subjects. Coronary sinus blood flow was evaluated by thermodilution. Arterial and coronary sinus blood samples were collected for the measurement of lactate and total and individual NEFA concentrations both in septic and control patients. There was an increase in lactate and total NEFA arterial concentrations with a marked increase in palmitic and linolenic acids. The uptake of the main NEFA (C14:0 to C18:2) was significantly decreased. In the control group, individual NEFA uptake was proportional to their arterial concentrations. This relationship was not observed in patients with sepsis: there was no preferential extraction of any particular NEFA. Furthermore, in patients with sepsis, myocardial oxygen consumption did not correlate with NEFA, but only with lactate uptake. Alterations in NEFA uptake were found to be constant during severe sepsis and are consistent with major disturbances in myocardial metabolism.

Influence of the surface area of different dialysis membranes on granulocyte adherence and superoxide generation.

Granulocyte adherence and superoxide anion generation were investigated in vitro in the presence of dialysis membrane fragments incubated with normal human polymorphonuclear cells. Dialysis membranes made from cellulosic material or non-cellulosic material like polyacrylonitrile, polymethylmetacrylate, and polysulfone were tested. The membrane surface area varied (1-5 cm2) while the membrane surface/polymorphonuclear cells ratio was maintained constant (2 X 10(6) cells/cm2). The contact of polymorphonuclear cells with increasing membrane surface area generated a significant decrease of superoxide anion generation (5-80% of inhibition) and produced an increase of granulocyte adherence (5-52%). This phenomenon was observed for all the tested membranes, whether opsonized zymosan or phorbol myristate acetate were used as stimuli. Similar results were obtained after washing the dialysis membrane or when polymorphonuclear cells were suspended in homologous serum. In vitro exposure of granulocytes to cellulosic or non-cellulosic dialysis membranes caused a surface-area dependent modification of polymorphonuclear functions.

Measurement of total, monomeric and polymeric IgA in human faeces by electroimmunodiffusion.

Total (t), monomeric (m) and polymeric (p) immunoglobulin A (IgA) levels were simultaneously measured in mixed faecal material collected over three consecutive days using a modified one-dimensional immunoelectrophoretic assay, which is a precise and reproducible method. Faecal t-, m- and p-IgA levels were statistically higher in 32 diarrhoeic patients than in a group of 16 healthy subjects (respectively 2.2, 2.6 and 2.0 times the normal). The values were also significantly different (P less than 0.001) when results were expressed as output per day in order to estimate the secreting capacity of gut. Moreover, the m-IgA/t-IgA percentages were significantly higher in faeces from diarrhoeic patients (42.3%) than in normal faeces (26.5%). These results confirm the importance of faecal IgA determination in estimating the local production of the IgA in various gastrointestinal tract disorders.

Dissociation and association rate constants changes following bilirubin binding affinity decreases.

The effect of sulfisoxazole, sodium salicylate, sodium cholate, urea and dimethyl sulfoxide on the kinetics of the bilirubin to human serum albumin at 24 degrees C and pH 7.40 was investigated. A marked decrease of the association constant was obtained. It was due mainly to that of the association rate constant, and might be an additional risk factor to the icteric newborn: when blood bilirubin increases, unbound bilirubin which cannot rapidly associate to albumin may reach a dangerous level, even when its equilibrium concentration is low.

Effects of storage on the pyruvate-lactate system and random migration of human granulocytes.

This work demonstrates a time-dependent loss of polymorphonuclear neutrophilic leukocyte (PMN) functions during the first 48 h with only slight lysis and release of cellular LDH. It confirms that storage decreases ATP levels in PMNs and significantly increases intracellular lactate and pyruvate. These data correlated with an inhibition of PMN migratory function and a considerable decrease in chemiluminescence response.

[Acetylcholinesterase titers in the amniotic fluid. Value of screening dysraphia of the central nervous system]. / A propos du dosage de l'activité acétylcholinestérasique dans le liquide amniotique. Valeur dans le dépistage des dysraphies du système nerveux central.

The authors report the results of 434 titrations of acetylcholinesterase in the amniotic fluid sampled by early amniocentesis, between the 17th and 24th week of amenorrhea. The biochemical technique used was quantitative and the values of the total cholinesterase activity (TchE) and the true acetylcholinesterase (AchE) were studied separately. Their conclusion is similar to that of other authors: the quantitative method, although satisfactory, has less value than the qualitative method using electrophoresis on polyacrylamide gel in order to screen or confirm the existence of a dysraphia of the central nervous system, because any amount of soiled fetal blood elevates the acetylcholinesterase level, titrated by the quantitative method.

Differential measurement of monomeric and polymeric IgA by one-directional immunoelectrodiffusion.

A technique to specifically quantify monomeric IgA and total IgA in colostrum has been developed using a modified one-dimensional immunoelectrophoretic assay. This method employed electrophoresis in antibody-containing polyacrylamide-agarose gel in the presence of a gel barrier which blocks polymeric IgA. The addition of PEG (polyethylene-glycol 6000) to the anodic gel increased the sharpness of the peaks, the height of which was proportional to the antigen concentration. This method proved to be sufficiently simple, precise, reproducible (CV less than 3%) and linear (from 20-300 mg/l) to measure the monomeric IgA: total IgA ratio rapidly (14 +/- 4.5% for 20 samples in duplicate). Immunoelectrodiffusion studies confirmed that human colostral and serum IgA standards could be used to determine directly monomeric IgA, total IgA and polymeric IgA levels (by difference) rather than to apply correction factors to estimate these IgA levels.

Free fatty acid microdetermination by gas-liquid chromatography without transmethylating effects of methylation procedure.

A fast and practicable gas-liquid chromatographic method for the quantitation of non-esterified fatty acids (C14:0-C18:2) from 100 microliter plasma is described. This technique includes extraction, purification using the solvents n-heptane and 0.5 M Na2CO3, and methylation by 0.1 M HCl-methanol. Extraction, quantification and optimal methylation conditions without transmethylation have been investigated. Reproducibility is good and results agree with values found in the literature.

Changes in human high density lipoproteins in patients with extra-hepatic biliary obstruction.

Plasma high density lipoproteins (HDL) from patients with obstruction of the common bile duct were studied by crossed immunoelectrophoresis and isoelectric focusing. All cholestatic HDL fractions were rich in phospholipids (51.5 +/- 9%) with high proportions of free cholesterol (13.8 +/- 1.5%). Moreover, crossed immunoelectrophoresis of sera against anti-Apo A revealed the presence of multiple immunoprecipitates sharply contrasting with the pattern formed by normal sera. Tandem crossed immunoelectrophoresis against anti-Apo A and anti-Apo B was performed with whole serum and with the HDL fraction from various cholestatic subjects. Crossed identity was observed for two of these precipitates, which could be explained by the decrease in HDL stability due to the detergent effect of bile salts. The most noteworthy changes found in cholestatic patients appeared to be the apolipoprotein pattern of HDL. Both Apo AI (48%) and Apo AII (5.5%) were greatly diminished and Apo E was present in remarkably high amounts (39%) with two additional isoforms (Apo E'1 and Apo E'2).

Plasma fibronectin time course in burned patients: influence of sepsis.

Plasma fibronectin time course was studied in 30 patients versus clinical criteria: body surface area burn (BSA), unit burn standard (UBS), and infection state. The mean value for all the population was lowest within days 1-3. No correlation was observed between fibronectin concentration and clinical criteria, either at admission or subsequently. Fibronectin levels of nonseptic patients (Group 1) did not differ significantly during the first days from those of patients who, at any time of their hospitalization, would become moderately infected (Group 2) or septic (Group 3). Afterwards, protein concentration of Group 1 increased regularly and hyperopsonization was observed from day 17 until the end of the study, day 35. In contrast, protein levels of Groups 2 and 3 remained low with a further improvement for moderately infected patients. A marked and significant difference was observed between nonseptic patients and septic patients, from the 6th postburn day. Variation of Groups 2 and 3 may be related to the infectious period, whatever the BSA or UBS index evolution. Since infection was related to low fibronectin level in the three deaths observed, it appears that opsonic protein cryoprecipitate would be of value in the treatment of burn victims.

New statistical approach in biochemical method-comparison studies by using Westlake's procedure, and its application to continuous-flow, centrifugal analysis, and multilayer film analysis techniques.

In this paper, we present an application of Westlake's method (Biometrics 32:741, 1976) in method-comparison studies in clinical chemistry. The techniques under study are continuous flow (CF), centrifugal analysis (CA), and multilayer film analysis (the Kodak Ektachem procedure KE). The experimental data are for plasma calcium and serum uric acid. It results from a particular regression procedure proposed by York (Can J Phys 44:1079, 1966) that the usual regression comparison technique (joint testing procedure) is irrelevant because it rejects the identity hypothesis for the three methods, whereas fixing a tolerable upper limit deviation, delta, between two methods would lead to the conclusion that, in 95% of cases, CF and KE results are equivalent for plasma calcium (delta less than or equal to 45 mumol/L) and CF is roughly equivalent to the other two methods for serum uric acid (delta less than or equal to 27 mumol/L).

[Determination of the acetylcholinesterase activities of the amniotic fluid on a centrifugal analyzer]. / Détermination des activités acétylcholinestérasiques du liquide amniotique sur analyseur centrifuge.

Amniotic fluid cholinesterase (ChE) activity measurements are realized to detect pre-natal neural tube defects. Their determinations on centrifugal analyzer are described. Total ChE activity is assayed at 412 nm with dithiobis-(nitrobenzoic-acid). Acetylcholinesterase activity is measured in the presence of ChE inhibitor, 14 X 10(-6)M lysivane; our results about the inhibitor concentration confirm the previous studies of Dale (Clin. Chim. Acta, 1977, 77, 407-413, Lancet, 1980, ii, 975) in opposition to those of Brock (Lancet, 1981, i, 95). Non NTD amniotic fluids from 92 women between the 17th and 20nd weeks of pregnancy were used to establish normal values. The technique proposed is rapid, accurate and needs only 40 microliters sample.

Total automated method for determination of cholesterol concentration in high density lipoprotein by heparin-magnesium-albumin precipitation.

We describe an automated procedure for determination of high-density-lipoprotein cholesterol in serum by use of heparin-MgCl2-albumin reagent. 'AutoAnalyzer' II equipment was used in which high-density lipoprotein was separated from precipitate containing very-low and low-density lipoproteins by filtering on-line across a cellulose acetate membrane. Cholesterol concentration was measured by the enzymic method of Allain. Good correlation was obtained using the automated method compared to the heparin-MgCl2-albumin (r=0.99) or sodium phosphotungstate-MgCl2 procedure (r=0.97). Contamination was minimal with a contamination coefficient lower than 2.5%. The method presented was linear (0 to 2.50 mmol/1) and could be applied to lipemic samples with a coefficient of variation better than 3%. This study showed thus that this new procedure was suitable for routine work with a good rate (60 samples/h) in almost any laboratory.