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D Raichvarg

Publications and source records attributed to D Raichvarg.

At least 73 records · Page 4Linked to original sources
PubMed1981

Characteristics of a lipid preparation (lipid A) from Haemophilus influenzae type a lipopolysaccharide.

Mild hydrolysis of Haemophilus influenzae type a lipopolysaccharide by ion exchangers yielded a lipid A extracted by chloroform. It contained phosphorus, glucosamine, and fatty acids. Myristic, palmitic, 3-hydroxymyristic, and oleic acids and two other unidentified long-chain fatty acids were found. The free lipid A was not toxic for mice at doses of up to 50 mg/kg and did not provoke a Shwartzman reaction. The Limulus test activity was positive up to 10(-12) g/ml, but the pyrogenicity in rabbits was lower than with the original lipopolysaccharide. However, the lipid A did induced a mitogenic response and polyclonal B-cell activation in mouse spleen cell cultures. Complexing lipid A with bovine serum albumin gave a nontoxic preparation which lost these immunological activities. Immunochemical studies showed that the major reactive determinants of this lipid-protein complex were altered after such a linkage. Consequently, the nontoxic and mitogenic lipid A isolated from H. influenzae type a did not exhibit all of the classical activities of lipid A preparations.

Animals↗
PubMed1981

Unmodified phagocytosis after periodate treatment of human granulocytes separated by a two-step method using Ficoll-Hypaque and polyvinylic alcohol medium.

A two-step method separating granulocytes and mononuclear cells from a single sample of 10 ml human blood is described. The technique combines a Ficoll-Hypaque treatment and a sedimentation in a Polyvinylic alcohol medium. This method (FHP) is then compared to the Ficoll-Hypaque-Dextran procedure. The FHP method requires approximately 2 h to be carried out and results in the preparation of granulocytes (greater than 99% purity) with high yield (40.7 % +/- 9.1). The cell viability exceeds 95%. Moreover the enzymic and phagocytic properties of polymorphonuclear cells are preserved after isolation. This method is then applied to study the influence of periodate treatment on nonspecific phagocytosis. In contrast with monocytes, we observed no decrease of phagocytic process.

Cell Separation↗
PubMed1981

[Determination of the prothrombin time and of the activated cephalin time wit semi-automatic Electra 600 apparatus (author's transl)].

This work studies the quality of the response of the Electra 600 for the determination of the prothrombin time (PT) and the activated cephalin time (ACT). The intra-serial precision was good for the PT and the ACT with normal or pathological plasmas (CV 2%). The precision was excellent for the PT (r = 0.98; Electra 600-fibrometer). The correlation coefficient varies between 0.85 and 0.95 for the ACT depending on the nature of the activator chosen. Lactescent plasmas having a protein concentration greater than 85 g/l should be treated manually for measurement of the PT. No interference was noted with other biological substances: eg glucose, bilirubin, hemoglobin. The increasing addition of heparin indicates a correct sensitivity of the response with Electra 600 both for short and long ACT. Autoanalysis renders the determinations of PT and ACT independant of the manipulator, that of the PT being much more rapid than with the manual method

Autoanalysis↗
PubMed1980

Comparative study of biological activities and mitogenic effect of extracts from Haemophilus influenzae type a.

Two preparations designated as PWE and NCE were obtained from H, influenzae type a by treatment with either phenol water or hypertonic NaCl citrate respectively. The protein content of NCE was three fold higher than for PWE. Electroimmunodiffusion against H. influenzae antiserum disclosed an immunological relationship between NCE and PWE. The toxicity for mice was lower for both antigenic extracts (LD50 PWE: 47 +/- 7 mg/kg; LD50 NCE: 943 +/- 5 mg/kg) than for E. coli LPS. Limulus assay showed that both H. influenzae extracts had a weaker potency (100 to 1000 times less) than E. coli LPS. Sanarelli and Shwartzman reactions failed for PWE and NCE. The blast transformation of DBA/2 and nude mouse spleen cells were strikingly different for the three preparations: PWE, NCE, and E. coli LPS. Neither extract from H. influenzae cells showed the biological properties of a classical endotoxin. We suggest that they are endotoxin-like substances.

Animals↗
PubMed1980

Preparation of a nontoxic and immunogenic polysaccharide fraction from a Haemophilus influenzae phenol-water extract.

A phenol-water extract from Haemophilus influenzae type a was hydrolyzed to decrease the toxicity without affecting the antigenicity of the preparation. We used partial hydrolysis for 15 h with ion exchangers in the presence of chloroform. The lipid fraction was collected into the organic solvent. The preparation obtained from the aqueous solution was designated the polysaccharide fraction. Rhamnose, glucose, galactose, mannose, and glucosamine were the major components of the polysaccharide fraction, and their molar ratios were determined by gas-liquid chromatography; 2.5% myristic acid was also found in the polysaccharide fraction. The mild hydrolysis of the polysaccharide fraction for 15 h caused a marked reduction in toxicity (50% lethal dose, 183 +/- 9 microgram/kg) and pyrogenicity. The generalized Sanarelli reaction was negative. The local Shwartzman phenomenon was not observed if chloroform and Dowex were exchanged three times during hydrolysis. Most of the antigenic components remained active after the hydrolytic process. The polysaccharide fraction could also induce the formation of circulating antibodies in rabbits and also increase the phagocytic process against H. influenzae from month 2 to 6.

Animals↗
PubMed1980

[Studies on an extract from Haemophilus influenzae type a. I.--Antigenic and immunogenic studies (author's transl)].

Haemophilus influenzae is the bacteria most commonly found in chronical bronchitis not treated by antibiotic therapy. Experimental studies have suggested that the destruction of the ciliated respiratory epithelium is in conjunction with the toxic product of the cell-wall of this bacteria. Endotoxin is extracted by phenol-water procedure. Toxicity is reduced by mild hydrolysis. Antigenicity of the preparation is controlled by gel diffusion in a parallel sides-tank diffusion and electroimmunodiffusion. These methods show that common antigenicity is not affected by hydrolysis. After immunisation by that preparation, circulating antibodies are detected by passive hemagglutination and immuno-precipitation. The immunized rabbits have agglutinin titer of 1 : 256th. Antigenicity of this bacterial extract is preserved and the preparation is still immunogenic.

Animals↗
PubMed1980

Determination of a new phagocytic index: influence of the bacteria strain and leukocyte species.

A scale of response, called phagocytic index (PI), is established to study the phagocytic function by measure of the Nitrobluetetrazoluim (NBT) reduction. 0 % and 100 % opsonic activity must be evaluated before the determination of PI which is calculated as follows: (Formula: see text) OD 0% vary with leukocyte species and the NBT batches, OD 100 % is depended on bacteria strains and nature of cells. Therefore PI must be performed in a system strictly characterized for bacteria, cells, and batch of NBT used. PI provides a better evaluation of bacterial phagocytosis as shown with antisera from rabbits immunized with Haemophilus influenzae.

Animals↗
PubMed1980

[Studies on an extract from Haemophilus influenzae type a. II.--Phagocytic capacity of sera obtained from rabbits immunized by this bacterial extract (author's transl)].

Opsonins may protect against infections. In this study, the different parameters of opsonization assay are strictly standardized. Results are expressed as percentage of opsonization. 0% and 100% opsonization must be established. The experiment without immunserum is used as the 0% opsonization. To determine the 100% opsonization an excess of reducing capacity is required. This is provided by crushed leukocytes. Rabbits are immunised by bacterial extract from Haemophilus influenzae type a. The hemagglutinins are detected in sera earlier (D + 30) and longer than the opsonic activity. Phagocytosis increases from the second month following the immunization. Percentage of opsonization is maintained at about 50% up to the sixth month. Alternatively, the percentage of phagocytosis is decreasing when heterologous bacteria are used. The serum thermolabile factors are necessary for the response. The phagocytic capacity is not modified whether leukocytes are obtained from immunized rabbits or not.

Animals↗
PubMed1980

[Critical aspects of actual methods for high-density-lipoprotein cholesterol quantitation].

In this study we compare various methods for h;igh-density-lipoprotein cholesterol quantitation: ultracentrifugation; electrophoresis either on cellulose acetate or on agarose gel; precipitation methods with polyanions-bivalent cations; adsorption procedure using concanavalin A (Con A). quantification by electrophoresis is slow and not precise. Except heparin-Mn++ and dextran (MM 5 X 10(5) and 2 X 10(6)) - CaCl2 procedures, precipitation and Con A methods own a good repeatability (VC 2%) and give a linear response after VLDL or LDL-VLDL addition to tested sera. Regression analysis of the data obtained using these methods in pairs demonstrate a correct accuracy (r > 0.95). The Student t-test shows that the usual values must be evaluated for each method. We suggest to use either phosphotungstate - Mg++ or Con A procedure as method for HDL cholesterol quantitation.

Adsorption↗
PubMed1980

Heparin--magnesium chloride--albumin method for enzymic measurement of cholesterol in high-density lipoprotein.

We describe a new method for measuring high-density-lipoprotein cholesterol in sera, with use of heparin, MgCl2, and albumin to precipitate very-low- and low-density lipoproteins, Lipoprotein electrophoresis and immunochemical methods show that high-density lipoprotein is completely and specifically isolated in the supernate, the cholesterol concentration of which is estimated by the enzymic method of Allain et al. (Clin. Chem. 20, 470, 1974). The precision of the method is excellent (CV = 1%) and the response is linear. Values so obtained correlate well with those obtained with the heparin-Mn2+ (r = 0.98) or the phosphotungstate-Mg2+ (r = 0.98) procedures. The technique is appropriate for routine clinical laboratory use.

Adult↗
PubMed1980

[Serum phospholipids determination by an automatic enzymatic method (author's transl)].

The serum phospholipids determination by an automatic enzymatic method (AEM) is suggested in this study. A comparison was made between the classical chemical method, the manual enzymatic method (MEM) and the AEM one. 100 serum samples were tested in this experiment and the correlation coefficient between these methods was found to be acceptable. The result indicates a good precision and a negligible contamination. The calibration curve is linear to 5 mmol/l. Triglyceride and cholesterol concentrations, glucose and high concentrated uric acid presence do not interfere on the value measured. However, the haemolysis and a large quantity of bilirubin in sera tend to induce a variation in the phospholipids determination.

Autoanalysis↗
PubMed1979

[Prostatic carcinoma: metabolic effect of percutaneous beta-estradiol (author's transl)].

Twenty one patients suffering from carcinoma of the prostate, confirmed histologically and previously untreated, received treatment in the form of 17 beta-estradiol administered percutaneously. At a dose of 6 mg of estradiol per day, testosterone levels fell to a mean of 1 ng/ml. No change in lipids, lipoproteins nor cholinesterase were detected.

Administration, Topical↗
PubMed1979

[Biological changes observed after infusion of modified gelatin in women who had cesarean sections].

We suggest to study some biologic parameters after perfusion by 1,000 ml modified gelatin to young women who have a caesarian operation. The level of gelatin is determined by previously proposed method. Gelatin is also revealed at electrophoresis. Concurrently, protein contents in sera and hematocrit are estimated. These investigations are also made at the same time for a reference population who has a ceasarian operation without perfusion of gelatin. The highest level of gelatin is reached at t(0) + 90 mn. Gelatin is not present in sera at t(0) + 6 hr. At electrophoresis the beta-globulins raise concurrently with the level of gelatin. The alpha-globulins decrease but that variation is small and later. Protein level decreases also in conjunction with hematocrit. Hematocrit value is about 30 p. cent. It seems to the authors that this value allows a better oxygen transmission to tissues. For reference population these biologic parameters are not modified.

Adult↗
PubMed1979

Chemical composition and biological activities of a phenol-water extract from Haemophilus influenzae type a.

Ribonucleic acid was removed from a phenol-water extract of Haemophilus influenzae type a by streptomycin sulfate. This preparation was called purified preparation or PP. It contained neutral sugars (glucose, galactose, mannose, pentose), glucosamine, amino acids, and fatty acids. Heptose and 2-keto-3-deoxyoctonic acid were not present. The biological properties and immunogenicity were compared with the activities of lipopolysaccharide of Escherichia coli or Salmonella typhimurium. Higher doses were necessary to obtain lethality in mice and Sanarelli and Shwartzman reactions with our preparations than were necessary with lipopolysaccharide. The Limulus test and pyrogen assay in rabbits gave the same results with purified preparation and lipopolysaccharide, but pyrogenicity of purified preparation was not destroyed by NaOH treatment. Purified preparation was not as immunogenic at low doeses for rabbits as lipopolysaccharide. The results were different from those obtained with lipopolysaccharide but similar to those known from peptidoglycan studies. The contamination of purified preparation with peptidoglycan was negligible and cannot explain the biological activities of purified preparation. We suggest that the phenol-water extract from H. influenzae is not a classical endotoxin, but rather an endotoxin-like substance.

Animals↗