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Biomedical subjects

M Becker

Publications and source records attributed to M Becker.

At least 361 records · Page 20Linked to original sources
PubMed1980

[Endoscopic retrograde cholangio-pancreatography in children (author's transl)].

Fifteen endoscopic retrograde cholangio-pancreatographies (ERCP) were performed between 1977 and 1979 in 13 children aged 2 months to 13.9 years (mean 8.9 years). All studies were done without intubation anaesthesia. Main indications were 1. acute (recurrent) biliary stasis, 2. persistent biliary stasis, 3. chronic pancreatitis, and 4. congenital malformation of the biliary system or the pancreas. Thirteen of the 15 investigations were successfully concluded. In nine cases both ductal systems were demonstrated, in two cases each either only the pancreatic or only the biliary ducts. The most frequent abnormal findings were seen in acute biliary stasis (four of five children), persistent biliary stasis (all four children) and congenital malformations (two of three children). There were no serious side effects. Except in young infants, for whom there are no properly sized instruments, ERCP in children provides no greater technical difficulties than in adults.

Adolescent↗
PubMed1980

Chronic viral hepatitis B in childhood. I. Clinical , Biochemical and histological results.

The results of clinical, biochemical and histological studies in 26 children with chronic hepatitis B are reported. Most cases were detected when diagnostic procedures were arranged because of non specific abdominal complaints, by routing tests after acute hepatitis or multiple transfusions, and by examination of family members. Hepatomegaly was found in half of the cases, splenomegaly in a quarter. Other clinical signs were rarely seen. Among the biochemical findings, elevated serum transaminase activities were the most reliable indicators of chronic hepatitis. There was a significant difference of the mean transaminase activities between patients with CPH and CAH. In 15 children CPH was diagnosed histologically. 9 children had CAH, 2 children showed signs of MinH.

Biopsy↗
PubMed1980

Complement studies in children with treated coeliac disease after gluten challenge.

Changes of the complement components in the sera of 13 children with treated coeliac disease were studied after gluten challenge. The levels of C 1 and C3-activator (factor B) were significantly decreased at 4 h after the challenge, as were the levels of total complement (CH 50) and the components C 1, C 4 and C 1-inactivator at 8 h. After 24 h most values returned to normal but there was another significant decrease in serum C 4 after 24 h, and for CH 50, C 1, C 2 and C 4 after 48 h.

Celiac Disease↗
PubMed1980

Temperature behaviour of human serum albumin.

Structural alterations of albumin, their dependence on concentration and the role of free --SH groups at thermal denaturation, as well as the reversibility of thermally induced structural changes, were studied. Application of various physical methods provides information on a series of structural parameters in a major concentration range. Apart from changes of the helix content, heat treatment gives rise to beta structures which are amplified on cooling and which are correlated with the aggregation of albumin. With rising temperature and concentration the proportion of beta structures and aggregates increases. At degrees of denaturation of up to 20% complete renaturation is possibly in every case. The structure content is concentration-dependent even at room temperature. It may be that intermolecular interactions induce additional alpha-helix structures which are less stable, however, than the ones stabilized by intramolecular interactions. Unfolding of the pocket containing the free --SH group of cysteine-34 enables disulphide bridges to be formed leading to stable aggregates and irreversible structural alterations. Through binding of N-ethymaleimide to free --SH groups, which blocks the formation of disulphide bridges, it is possible to prevent aggregation and irreversible conformational changes. At temperatures below 65--70 degrees C, oligomers are formed mainly via intermolecular beta structures.

Circular Dichroism↗
PubMed1980

Fc and C3 receptors as membrane differentiation markers of acute myelogenous leukaemia cells.

Acute myelogenous leukaemia cells (AML) and cells of chronic myelogenous leukaemia blast crisis (CGL-CB) were examined for the presence of receptors for Fc IgG fragment (FcR), receptors for the complement components (CR1 and CR2), and the surface immunoglobulins including the light kappa and lambda type chains. The leukaemia blasts were found to be the cells poor in receptors and poorly differentiated. As a rule, they contained very small amount of detectable FcR, CR2, and CR1. Analysis of AML cell populations separated on the discontinuous density gradient revealed that the appearance of FcR was followed by CR2 and CR1. The CGL-CB cells were more differentiated immunologically since, in comparison with the AML cells, in greater percentage they expressed the FcR, and the receptors for complement. Assays for surface immunoglobulins indicated that they were not an active product of the leukaemic blasts, but rather exogenous in origin.

Complement C3↗
PubMed1980

Response of dog parathyroid glands to short-term alterations of serum calcium.

Parathyroid (PT) glands of dogs were exposed to low or high serum calcium by infusion of either EGTA or CaCl2. Infusion of EGTA resulted in an increase of parathyroid hormone (PTH) and infusion of CaCl2, in a decrease of this hormone. The PT glands excised either at the beginning or at the end of the infusions were examined by electron microsoopy. After infusion of EGTA, activated cells showed a dense matrix, prominent Golgi apparatus, rough endoplasmic reticulum (rER) with narrow cisternae, and an incrased tortuosity of the plasma membrane, accompanied by an enlargement of the intercellular spaces. Infusion of CaCl2 resulted in a distention of the rER cisternae, disorganization of the Golgi apparatus and a decreased tortuosity of the plasma membrane. It is concluded that (1) PT cells may contract in the course of activation; (2) storage capacity for PTH is low, and (3) PT cells may be stimulated or inhibited to promote biosynthesis of PTH within minutes.

Animals↗
PubMed1980

Circular dichroism studies of substance P and its C-terminal sequences. CD spectra in aqueous solution and effects of hydrogen ion concentration.

CD spectra of substance P (SP) and its C-terminal partial sequences have been measured in diluted aqueous solution including variation of hydrogen ion concentration. In the far u.v. region there is an overlapping of the amide CD absorption by the CD of the phenylalanine residue aromatic side chains (217-220 nm). This complex CD absorption is reduced during changes from acidic to alkaline pH, especially in those cases where a phenylalanine residue is at the N-terminus of the peptide chain. These CD changes dependent on pH are due more to charge effects on the aromatic chromophores than to substantial conformational changes. However, solvation effects on the conformational features of SP peptides caused by the deprotonation of the amino groups have to be taken into account. CD and potentiometric titrations indicate that the N-terminal alpha-amino groups of the SP peptides in general are freely accessible to the solvent. Our studies did not give any evidence of the occurrence of ordered structures of SP peptides in diluted aqueous solution.

Amino Acid Sequence↗
PubMed1980

Antibody-dependent redistribution and release of immunological complexes in cells of human chronic leukemias.

Redistribution and the ability for removing immunological complexes in CLL and CGL cells treated with the specific anti-leukemia antigens were investigated. The immunofluorescence method at 4 and 37 degrees C was applied at different times of cell incubation with antigens. It was shown, that incubation at 4 degrees C even carried out for 18 h, neither caused a clear aggregation nor a release of immunological complexes from the leukemia cell surface, whereas at 37 degrees C considerable differences in mobility of CLL and CGL cells were observed. In CGL cells quite a rapid redistribution followed by the removal of antigen-antibody complexes was observed, while CLL cells have shown the ability for aggregation only, without clear polarization and without releasing the formed complex from the cell surface.

Antigen-Antibody Complex↗
PubMed1980

Surface immunoglobulins in human chronic leukemia cells.

By means of the cytotoxic and immunofluorescence tests, frequency of various classes of immunoglobulins (IgG, IgA, IgM, IgD, IgE) and light chains was examined in peripheral pathologic blood cells of patients with chronic granulocytic and lymphatic leukemia. The dominant immunoglobulins were of the IgD and IgE classes. Light chains of both types were present in cells of chronic granulocytic leukemia, and kappa type in chronic lymphatic leukemia. Use of the method of resynthesis of digested immunoglobulins in vitro confirmed the monoclonal origin of chronic lymphatic leukemia in humans.

Granulocytes↗
PubMed1980

Delayed hypersensitivity reactions in patients with acute leukemias and blastic crisis of chronic granulocytic leukemia.

Delayed hypersensitivity reactions were studied in 34 patients with acute leukemias and 13 patients in blastic crisis of chronic granulocytic leukemia during the course of the disease. All patients were skin tested with PPD, Candida antigen, SK/SD and DNCB. A positive correlation existed in majority of patients between the response chemotherapy and delayed hypersensitivity reactions in the tested patients.

Acute Disease↗
PubMed1980

Circulating immune complexes in children with acute poststreptococcal glomerulonephritis.

Sera from 22 children with acute poststreptococcal glomerulonephritis were examined for circulating immune complexes (CIC) during the acute phase of the disease and six to eight months following its onset. CIC were found in 10 of 22 (45%) children during the acute phase and in 4 of 19 (21%) during follow-up. No correlation was found between the presence of CIC during the acute phase and disease severity as measured by several clinical and laboratory parameters. There was, however, a positive correlation between the presence of CIC in serum and the duration of proteinuria following disease onset. The possible role of CIC in the induction of chronic glomerulonephritis following acute poststreptococcal glomerulonephritis is discussed.

Acute Disease↗