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A Scharfman

Publications and source records attributed to A Scharfman.

At least 37 records · Page 2Linked to original sources
PubMed1988

The complexity of mucins.

Mucins represent the main components of gel-like secretions, or mucus, secreted by mucosae or some exocrine glands. These high-molecular-weight glycoproteins are characterized by the large number of carbohydrate chains O-glycosidically linked to the peptide. The determination of mucin molecular weight and conformation has been controversial for several reasons: 1) the methods used to solubilize mucus and to purify mucins are different and 2) the molecules have a strong tendency to aggregate or to bind to other molecules (peptides or lipids). Recently, electron microscopy has shown the filamentous shape of most mucins and their polydisperse character which, in some secretions, might correspond to a polymorphism of the peptide part of these molecules. The recent development of high pressure liquid chromatography and high-resolution proton NMR spectroscopy has allowed major progress in the structural study of mucin carbohydrate chains. These chains may have from 1 to about 20 sugars and bear different antigenic determinants, such as A, B, H, I, i, X, Y or Cad antigens. In some mucins, such as human respiratory mucins, the carbohydrate chain diversity is remarkable, which raises many questions. Mucins are molecules located at the interface between mucosae and the external environment. The carbohydrate chain diversity might allow many interactions between mucins and microorganisms and play a major role in the colonization or the defense of mucosae.

Animals↗
PubMed1987

Comparison of hydrolases, peroxidase and protease inhibitors in bronchoalveolar fluid from Macacus cynomolgus and human controls.

1. Serial bronchoalveolar lavages were performed on a subhuman primate (Macacus cynomolgus) in order to give an experimental model for silicosis. 2. We have measured glycosidases, proteases, peroxidase and antiproteases of the BAL fluids from seven normal monkeys. 3. The results obtained were similar to those found in human control BAL fluids. 4. For monkeys, the repetition of the bronchoalveolar procedure does not seem to have an important influence on the values obtained. 5. The present results will now permit sequential follow up studies during the course of experimental silicosis.

Animals↗
PubMed1986

The high lipid content of respiratory mucins in cystic fibrosis is related to infection.

Seven human bronchial mucins secreted by patients suffering from chronic bronchitis or from cystic fibrosis were prepared by exclusion from a Sepharose CL-2B column in 6 M guanidinium chloride. Their behaviour in CsBr density gradient centrifugation was compared. The mucin fractions were associated with peptides and lipids, the abundance of which decreases with the buoyant density. The lipid content of the mucin fractions appears to be related to the infectious character of the bronchial secretion and seems to be independent of cystic fibrosis. The content of fatty acids remaining after delipidation of mucin fractions from patients with chronic bronchitis or with cystic fibrosis also appears to be related more to the purulent character of the sputum than to cystic fibrosis or chronic bronchitis.

Bronchi↗
PubMed1983

Activation of bronchial mucin proteolysis by 4-aminophenylmercuric acetate and disulphide bond reducing agents.

High molecular weight bronchial glycoproteins, as nearly native as possible, were treated with either 2-mercaptoethanol or 4-aminophenylmercuric acetate (APMA): analytical electrophoresis revealed that a decrease in molecular weight of glycoproteins coincided with the disappearance of some proteins associated with high molecular weight bronchial glycoproteins. These modifications were not observed if high molecular weight bronchial glycoproteins were incubated with paramethylsulphonyl fluoride and EDTA, two synthetic protease-inhibitors, prior to 2-mercaptoethanol or APMA action. These data suggest that protease-antiprotease complexes are associated with bronchial mucins and that reducing agents or APMA activate proteases.

Bronchi↗
PubMed1983

[Bronchoalveolar lavage in pneumoconiosis of coal miners. Biochemical aspects].

Broncho-alveolar lavage (LBA) was performed in 17 pneumoconiotics. The liquid obtained was analysed after gentle centrifugation to remove the cellular element, so that biochemical factors might be sought contribution to the evolution and progressive transformation to fibrosis. The percentage of liquid gathered was generally greater. Among the glycosidases found in all the 17 LBA analysed, the beta-D-glucuronidase, which was not detected in the LBA control subjects, was also found during the course of other pulmonary disorders. The elastolytic activity was characterized in 12 out of 17 LBA. In part it could originate from alveolar macrophages. An elevated number of macrophages (greater than 20 X 10(6) for the whole lavage) allied to the presence of elastolytic activity was found in 7 of 8 patients presenting with a pneumoconiosis and signs of progressive pulmonary disease. The collagenase and cathepsin B were present in the LBA of certain pneumoconiotics, but the significance of their presence is still unknown. The three major antiproteases of the serum exist in the LBA of pneumoconiosis. The quantity of alpha 1-antiprotease has identified a group of 6 patients whose LBA showed raised alpha 1-antiprotease, an elastolytic activity and for 5 of them progressive outcome.

Adult↗
PubMed1981

[Effect of trypsin on the cell surface : influence on the lysosomal exocytosis of alveolar macrophages of the guinea pig].

Secretion of the main lysosomal hydrolase, N-acetyl-beta-D-glucosaminidase of Guinea Pig alveolar macrophages was studied in vitro; without stimulus of phagocytosis or pinocytosis, glycosidase secretion was increased by trypsin. Enzymatic activity secreted under trypsinisation was heterogeneous as compared to the enzymatic activity secreted by control cells: under incubation with Concanavalin A (Con A), glycosidase activity secreted by trypsinised cells decreased by 30%, whereas Concanavalin A did not alter enzymatic activity secreted by control cells.

Acetylglucosaminidase↗
PubMed1976

[Bisalbuminaemia in pancreatitis: structural modifications of human serum albumin by proteolytic enzymes of the pancreas (author's transl)].

Bisalbuminaemia in pancreatitis is a transient abnormality related to the presence, on electrophoresis of the serum, of a fast-moving albumin; this abnormal form is also found, in large amounts, in the ascitic or pleural effusions of the patients. Experiments reported here indicate clearly that the fast albumin can be produced by a degradation of normal serum albumin by the proteolytic enzymes of the pancreas (chymotrypsin or elastase in association with carboxypeptidases A and B). Stuctural analysis of the isolated fast albumin of the patients shows that the C-terminal end of the molecule is different from normal serum albumin, which can be understood by a limited enzymatic degradation by chymotrypsin or elastase followed by the action of carboxypeptidases. The discovery of bisalbuminaemia in a patient affected by pancreatitis is suspicious of the presence of an ascitic or pleural effusion and of a pancreatic pseudo-cyst with a fistula emerging in the effusion.

Carboxypeptidases↗
PubMed1976

[Studies on the activities of peptidases from human leucocytes, and human and guinea pig alveolar macrophages (author's transl)].

Peptidases activities were compared in human leucocytes, guinea pig and human alveolar macrophages. Seversl endo- and exopeptides were characterized; some of them were active at acid pH and others at neutral and alkaline pH. Leucocytes and alveolar macrophages had proteolygic activity for hemoglobin, fibrinogen, collagen and elastin. Using synthetic substrates, several enzymes were characterized: arylamidase, aminopeptidase, carboxypeptidases A and B and cathepsins A and C. The enzymatic activities were much higher in alveolar macrophages than in leucocytes.

Animals↗
PubMed1975

[Comparative studies of the acid hydrolases of human leucocytes and human and guinea pig alveolar macrophages. I. Study of the activities of glycosidases, arylsulfatase and acid phosphatase (author's transl)].

Acid hydrolase activities were compared in human leucocytes, guinea pig and human alveolar macrophages. Several enzymes were characterized: N-acetyl-beta-D-glucosaminidase, N-acetyl-alpha- and beta-D-galactosaminidase, alpha and beta-D-galactosidase, alpha-D-mannosidase, alpha-L-fucosidase, beta-D-glucuronidase, neuraminidase, acid phosphatase and arylsulfatase. The enzymatic activities were lower in leucocytes than in alveolar macrophages, higher in human macrophages than in guinea pig macrophages, except for beta-D-glucuronidase, acid phosphatase and arylsulfatase activities.

Acetylglucosaminidase↗
PubMed1975

[Comparative study of neuraminidases from "Diplococcus pneumoniae" and "Clostridium perfringens"].

Neuraminidases have been purified from the culture medium of two microorganisms, one aerobic, Diplococcus neumoniae, the other anaerobic, Clostridium perfringens. The enzymatic properties of the 2 neuraminidases have been studied (pH optimum; effect of cations; activity toward different substrates: neuraminyllactose, dilactaminyllacto-N-tetraose, gangliosides, alpha1-acid glycoprotein, Collocalia glycoprotein, ovine submaxillary mucin, porcin intestinal and human bronchial mucins).

Cations, Divalent↗