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Biomedical subjects

N Moatti

Publications and source records attributed to N Moatti.

At least 91 records · Page 5Linked to original sources
PubMed1991

Fractionation of charge-modified low density lipoproteins by fast protein liquid chromatography.

We describe a methodology developed to separate different forms of charge-modified low density lipoproteins (LDL) using the fast protein liquid chromatography (FPLC) system from Pharmacia. Lipoproteins were isolated by sequential ultracentrifugation and introduced onto an anion-exchange column (Mono Q HR 5/5). The multistep NaCl gradient elution was optimized and the analytical variables were determined on copper-oxidized LDL. After oxidation by copper for various times (up to 48 h), five forms were obtained (fractions A, B, C, D, and E). Within-run and day-to-day reproducibility were better than 8.6% and 10%, respectively. Protein and cholesterol recovery after the chromatographic separation was good (greater than 82%) and the detection limit was about 1 microgram. The more negative forms of collected LDL were mainly characterized by an increase in the lipid peroxidation product content, a depletion of vitamin E, an alteration of apoB and increased degradation by macrophages. The proposed methodology was applied to the study of LDL modifications generated by human umbilical endothelial cells and the protective effect of antioxidants (vitamin E and probucol).

Antioxidants↗
PubMed1991

Monoclonal and oligoclonal gammopathies in heart-transplant recipients.

Immunoglobulin abnormalities in serum from 76 heart-transplant recipients were examined by cellulose acetate and agarose gel electrophoresis. Monoclonal components were typed by immunofixation. IgG, IgA, and IgM and total kappa and lambda light chains were quantified by immunonephelometry. We confirm that both monoclonal and oligoclonal immunoglobulin banding are common in serum from these patients. Of the 149 serum samples examined, 21 (15%) had one monoclonal component and 53 (35%) had two or more. These monoclonal immunoglobulins were generally present at a low concentration and were transient. The class of immunoglobulins most commonly involved was IgG (about sevenfold more numerous than IgM); monoclonal IgA components and free light chains were not detected. The nephelometric kappa/lambda and heavy chain/light chain ratios were poor indicators of these abnormalities. Immunoglobulin abnormalities were not correlated with the sex and age of recipients, the pre-existing cardiopathy, the time since transplantation, or plasma concentrations of cyclosporine, but did correlate with plasma immunoglobulin concentration, biopsy findings, and viral infections, especially cytomegalovirus (CMV). A monoclonal IgG purified from a patient with a high titer of anti-CMV antibodies did not react with CMV antigens. The origin of these immunoglobulin abnormalities is unclear. Our data suggest that the presence of monoclonal or oligoclonal banding in heart-transplant recipients is of limited prognostic significance.

Adult↗
PubMed1991

[Membrane phospholipid peroxidation in renal insufficiency and chronic hemodialysis].

Lipid peroxidation is a result of the fatty acid side-chains of cellular membrane phospholipids attack by oxygen-derived free radicals. It has been suggested that some of the complications related to haemodialysis may be due to ineffective antioxidant systems and/or an increased free oxygen radical production. Serum antioxidant activity in patients undergoing regular dialysis treatment has been shown to be significantly decreased and to exhibit high malondialdehyde levels indicating that the patients were susceptible to cellular injury by lipid peroxidation. Superoxide dismutase and glutathion peroxidase activities are decreased in plasma and erythrocytes. Moreover, in uremia, blood cell and mononuclear cell membranes contents of vitamin E are reduced. Thus, chronic uremic patients seem to have defective plasma and cellular antioxidant mechanisms together with an increase of circulating free radical reaction products.

Antioxidants↗
PubMed1990

Serum lipid abnormalities in heart transplant recipients: predominance of HDL2-like particles in the HDL pattern.

Accelerated coronary atherosclerosis is a major risk limiting long-term survival after heart transplantation and is commonly associated with dyslipoproteinemia even in subjects who were not dyslipoproteinemic before intervention. The purpose of this study was to analyse the abnormalities in the lipid profiles of 2 different groups of heart-transplanted males: 18 subjects with underlying ischemic heart disease (IHD) and 19 subjects with non-obstructive cardiomyopathy of unknown aetiology (CM). Both groups were compared to 33 healthy males. All patients were under immunosuppressive therapy including prednisone, cyclosporin A and azathioprine. A moderate hyperlipidemia was found in all transplant recipients, associated with high HDL-cholesterol concentrations in the CM group (1.80 +/- 0.37 vs. 1.29 +/- 0.23 mmol/l) and normal HDL-cholesterol levels in the IHD group (1.40 +/- 0.23 mmol/l). HDL subfractionation showed a marked increase in HDL2-cholesterol (CM: 1.12 +/- 0.32; IHD: 0.69 +/- 0.28; control: 0.40 +/- 0.17 mmol/l) while HDL3-cholesterol was significantly lower than in the control group. Analysis of HDL particle sizes showed in all transplant subjects an increase of an intermediate size particle HDL2a (diameter 9.0 +/- 0.10 nm) which is a minor form in control subjects. In the CM group, both the common HDL2b (10.2 +/- 0.13 nm) and HDL2a were abundant in 13 of 17 patients. The pattern was more heterogeneous in the IHD group but witnessed to a high frequency of HDL2a particles either alone (5/14) or associated with larger HDL2b (4/14) or with small HDL3 (4/14).(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiomyopathies↗
PubMed1990

[Evaluation of 2 bacterial filters connected to the respirator for the prevention of nosocomial pulmonary infection].

Among 37 patients that are admitted for a more than 3 days breathing reanimation, 19 are ventilated with bacterial filter Pall BB 22 15 and 18 with Darex Hygrobac, exchanged every days and connected to the Y piece. In this study, 6 patients are ventilated with a humidifier (pilot population). For these 43 patients, 130 protected swabs were made with the RCS Biotest placed on the expired gaz. The day of the taking off the expiratory tube was rinsed with 100 ml of aseptic water which are strained on the membrane. The two filters give very good and comparable bacteriological results. The filters prevents nosocomial pulmonary infections making a bacterial frontier between the patient and the respirator and reducing aerial contamination from one patient to another.

Air Microbiology↗
PubMed1989

Glutamine dependency of human skin fibroblasts: modulation by hexoses.

The combined effects of carbohydrates and glutamine were investigated in diploid strains of normal human skin fibroblasts cultured for 21 days under eight different culture conditions: hexose-free medium or medium containing D-glucose, D-galactose, or D-fructose, with or without added glutamine. Cell growth, hexose consumption, lactate production, intracellular glycogen content and extracellular amino acid levels were measured every third to fourth day. In the presence of glutamine, cells reached a higher saturation density in fructose medium than in glucose or galactose medium but per cell consumption of fructose and galactose was much less than that of glucose. Consumption of all three carbohydrates per unit cell growth exhibited three distinct phases: Days 1-3, 3-10, and 10-20, respectively. In the absence of glutamine the rate of cell growth was not altered in glucose or galactose medium, but slowed down considerably in fructose medium. Glutamine deprivation also led to changes in hexose consumption. In hexose-free media the cell growth rate at first was very slow, but rose after 2 or 3 weeks of culture. The levels of extracellular nonessential amino acids varied according to medium and growth phase. One of the most exciting findings was that human fibroblasts are able to maintain a slight excess of glutamine in all media not supplemented with glutamine and, more surprisingly, to synthesize it in a medium containing galactose and glutamine.

Amino Acids↗
PubMed1989

Monitoring of heart allograft rejection by simultaneous measurement of serum beta 2-microglobulin and urinary neopterin.

In patients with heart transplant, the combined determination of serum beta 2-microglobulin and urinary neopterin, as rejection marker, prevented the interference by renal function and cyclosporin therapy. Unfortunately, the simultaneous measurement of these two parameters cannot distinguish between a rejection episode and the early stage of viral infection.

Biopterins↗
PubMed1988

The Philadelphia variant of galactokinase in human erythrocytes: physicochemical and catalytic properties.

The Philadelphia variant of galactokinase (GALKP) is responsible for an asymptomatic disorder of galactose metabolism. Individuals with GALKP phenotype are common among black people. They exhibit reduced galactokinase (GALK) activity in their red blood cells but normal activity in their white blood cells. We explored the biochemical characteristics of hemolysates from individuals with the GALKP phenotype and from controls. In mixed hemolysates from a control and a proband, the GALK activity measured did not suggest the presence of an inhibitor. We observed that the catalytic properties, pI and thermolability in hemolysates from controls and GALKP individuals were identical. Thus, the Philadelphia variant of galactokinase seems not to alter biochemical properties of the red blood cell enzyme. A silent amino acid substitution, or the dysfunction of a regulatory gene might be likely suggested to explain the reduced enzyme activity.

Black People↗
PubMed1988

A study of fibrinogen and fibrinolysis in 10 adults with nephrotic syndrome.

In 10 patients with nephrotic syndrome (NS), the coagulation inhibitors, the fibrinolytic system and several functions of the fibrinogen-fibrin molecule were studied. Among the coagulation inhibitors, only antithrombin III (AT III) was found decreased and correlated with serum-albumin levels. Venous occlusion test provoked a normal tissue plasminogen activator (tPA) release in all patients. The plasminogen activator inhibitor (PAI) had an increased activity in 5 out of the 10 patients. Thrombin and reptilase times were found abnormal in most patients. The thrombin time (TT) prolongation correlated with serum albumin levels and was corrected by adding purified albumin. The fibrinogen was purified from each of the 10 patients' plasma. Only 2 of them showed abnormal polymerization in purified system, suggesting dysfibrinogenaemia. Other functions (thrombin binding, tPA stimulating activity, lysis by purified plasmin) were found normal except in one of the 2 patients with dysfibrinogenaemia whose fibrinogen lysis by plasmin was delayed. It is concluded that an abnormal fibrinogen molecule is not the most frequent explanation for thrombin time prolongation in NS.

Adult↗
PubMed1988

The Philadelphia variant of galactokinase: impaired [1-14C]galactose oxidation by intact erythrocytes.

Probands with the Philadelphia variant of galactokinase (GALKP) are black people who exhibit reduced galactokinase (GALK) activity in their red blood cells (RBC), but normal activity in their white blood cells (WBC). This reduced RBC GALK was demonstrated in disrupted erythrocytes. To investigate the possibility of a missing cofactor in hemolysates from individuals with GALKP phenotype, we compared [1-14C]galactose oxidation by intact erythrocytes, with the direct GALK assay in disrupted erythrocytes. The rate of [1-14C]glucose oxidation was also measured in order to differentiate an impaired galactose metabolism from a defect further along the pentose phosphate pathway. A good correlation (p less than 0.001) was found between the direct GALK assay and [1-14C]galactose oxidation in control subjects, which indicates that this method can be used effectively for the detection of GALK defects. This was further supported by studies on samples from heterozygotes and homozygotes for the GALKG deficient gene. For all the probands with a GALKP phenotype, diminished CO2 production from galactose was observed in the absence of impaired glucose metabolism. This allowed us to confirm the existence of a GALK deficiency in intact erythrocytes due to the GALKP variant. Further studies of RBC GALK catalytic properties are needed to investigate the molecular basis of this GALK deficiency.

Blood Glucose↗
PubMed1988

Use of platelets, mononuclear and polymorphonuclear cells in the diagnosis of glycogen storage disease type VI.

We determined glycogen concentration and phosphorylase 'a+b' and phosphorylase a activities in platelets, mononuclear and polymorphonuclear cells from control subjects and patients with phosphorylase kinase deficiency (glycogen storage disease IX) and liver phosphorylase deficiency (glycogen storage disease VI). Variations according to cellular type and to subjects' age (1-40 years) were established. Variable glycogen overloading was found in all our patients. Glycogen storage disease (GSD) VI was characterized by a diminished total phosphorylase activity with a low or normal a/(a+b) ratio of phosphorylase activity. GSD IX was characterized by a very low residual activity of phosphorylase a with an 'a+b' activity low or normal.

Adult↗