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Biomedical subjects

B Nagy

Publications and source records attributed to B Nagy.

At least 127 records · Page 7Linked to original sources
PubMed1982

Pyrolysis of Precambrian kerogens: constraints and capabilities.

Precambrian kerogens are currently considered to be the primary candidates for the search of biochemical fossils. Degradation of kerogens by relatively "mild" pyrolysis techniques, such as under high vacuum, can liberate indicative structural moieties which were incorporated in, and perhaps shielded by, these solid and highly condensed, basically aromatic substances. It is necessary to observe analytical constraints (sample size and shape, temperature, pressure, time, etc.) in order to prevent an overabundant yield of secondary pyrolyzates (inter- and intramolecular rearrangements) which can prevent kerogen characterization. Potential biochemical fossils have been found in Precambrian kerogens. Demonstratable syngenetic biochemical fossils are expected after kerogen diagenesis and catagenesis is understood in sufficient detail, and when pyrolysis is augmented by multiple, improved analytical techniques.

Biological Evolution↗
PubMed1982

Partial biochemical maturation of aneurally cultured human skeletal muscle.

We studied cultures of human skeletal muscle in vitro and established standards for biochemical markers of cellular differentiation. DNA synthesis ceased at the time of fusion, implying the absence of fibroblasts. Myosin heavy-chain synthesis, creatine and pyruvate kinase activities, and isoenzymes of creatine kinase were measured serially over 36 days. Filamin and fibronectin proteins were identified in these cultures. Compared to chick muscle in culture, human skeletal muscle cells remained relatively immature. These data provide a basis for the study of diseased human muscle cells in culture.

Animals↗
PubMed1982

Pilus antigen 987P produced by strains of Escherichia coli serotypes O141:K--, H- and O8:K85:H--.

Escherichia coli strains isolated from the alimentary tract of 68 weaned and 44 unweaned pigs with diarrhoea in various parts of Hungary, were tested for the presence of pilus antigens K88, K99 and 987P. K88 was detected in 30% of the strains from newborn pigs and in 12% of the strains isolated from weaned pigs. One strain carried K99. Based on agglutination test and immunoelectron microscopic studies with specific absorbed antisera, five non-haemolytic E. coli strains isolated from newborn pigs were found to produce so-called 987P pili. Three of these strains were designated serologically as O8:K85:H--,987P+ and two as O141: K--:H--,987P+. The Y1 cell assay, the infant mouse assay, and the ligated intestinal loop assay in less than 3-week-old pigs indicated that none of the strains produced heat-labile enterotoxin but all produced a heat-stable enterotoxin detectable in infant mice and in pig loops (STa). All the strains induced diarrhoea in newborn, colostrum deprived pigs and colonized the lower small intestine by adhesion to the villous epithelium. The results have confirmed earlier findings about adhesive virulence attributes caused by 987P pili.

Animals↗
PubMed1981

Duchenne muscular dystrophy: adenosine triphosphate and creatine phosphate content in muscle.

In carrying out a new study of nucleotide concentrations in dystrophic muscle, we utilized myosin as a reference base. In nine control vastus lateralis muscle samples, nucleotide concentrations were 105 +/- 11 (SEM) moles of adenosine triphosphate (ATP) and 446 +/- 57 (SEM) nmoles of creatine phosphate (CP) per milligram of myosin. In seven Duchenne dystrophic vastus lateralis muscle samples, nucleotide concentrations were 127 +/- 25 (SEM) nmoles of ATP and 462 +/- 119 (SEM) moles of CP per milligram of myosin. The CP:ATP ratio of 3.6 +/- 0.367 from Duchenne muscle was not significantly different from normal, 4.32 +/- 0.243 ((p less than 0.20). In addition, myokinase activity, which is automatically assayed in these assays, was significantly increased in the Duchenne samples (p less than 0.10). The percent of myosin per total protein in the Duchenne biopsies was also diminished by 29% (p less than 0.01). These studies suggest that ATP and CP concentrations are not decreased in Duchenne dystrophic muscle when expressed in relation to the amount of contractile protein.

Adenosine Triphosphate↗
PubMed1980

Chemotactic and random movement of human newborn monocytes.

Boyden's method was used to assess the chemotactic and random mobility of monocytes from healthy newborns, children aged 3--8 years, and adults aged 20--28. Monocyte chemotaxis in the newborn was decreased in comparison with that of control groups. No difference was observed in random cell mobility in the groups examined. Monocyte chemotactic activity in infants over 3 years of age was the same as in adults. According to our results, the leading-front and lower-surface evaluation methods, in newborns at least, do not give the same information on chemotaxis.

Adult↗
PubMed1980

Vaccination of cows with a K99 extract to protect newborn calves against experimental enterotoxic colibacillosis.

Pregnant cows and heifers were vaccinated with a crude K99 extract prepared from an Escherichia coli K-12, K99 strain. A similar group, injected with an extract prepared from the K-12 parent strain, served as a control. Eleven calves were born to both groups and challenged orally with a mean of 1.6 x 10(11) bacteria of enterotoxic E. coli B41 (O101:K99+, ST+) at the time of first colostrum uptake (1 to 7 h after birth). As a result of challenge, no death occurred in the vaccine group, but four calves died in the control group. Six calves in the vaccine group and all calves in the control group developed diarrhea. Colostral anti-O101 titers were very similar in both groups. Anti-K99 titers of colostral samples from the vaccinated dams were, however, significantly higher as compared to those of the controls. It is suggested that colostral antibodies, raised against the crude K99 extract vaccine, exerted a protective effect on newborn calves against the challenge enterotoxigenic E. coli O101:K99+, Ent+ strain.

Animals↗
PubMed1979

2,5-Dimethylfuran from approximately 2.7 x 10-year-old Rupemba-Belingwe stromatolite, Rhodesia: Potential evidence for remnants of carbohydrates.

2,5-Dimethylfuran, 2-methylfuran, and C(9)-C(20)n-alkanes have been isolated from the kerogen of a Rupemba stromatolite. These furans could be the oldest known stable remnants of biological carbohydrates if it is possible to prove that their progenitors are as old as the rock. Experiments showed that it is improbable that these compounds are analytical artifacts or laboratory contaminations. Postdepositional contaminations caused by fluids flowing through the rocks seem doubtful because of minimal permeability, which is supported by petrographic observations. Contamination by diffusion also appears to be unlikely. Because the rock had a mild temperature history, these molecules could have survived since Archean time. Because of all the evidence, the furans and alkanes are quite likely biochemical fossils.

Journal Article↗
PubMed1979

Biliary transport of IgA: role of secretory component.

Biliary transport of rat immunoglobulin was studied by perfusion of isolated rat liver with blood containing radiolabeled immunoglobulin. Transport to bile was selective for polymeric IgA. Between 15 and 27% of polymeric IgA was transported from blood to bile during a 210-min perfusion period, and approximately 60% of the IgA transported to bile bore secretory component. Small quantities of IgM (0.12%) were transported; transport of IgG2 alpha, IgE, or monomeric IgA was not detected. Purification of radiolabeled polymeric IgA by affinity chromatography on human secretory component-Sepharose yielded a fraction that was transported more efficiently (i.e., up to 40% transported). In contrast, secretory IgA (colostral or biliary) was transported 1/25th to 1/12th as well as polymeric IgA myeloma protein. Complexes of 125I-labeled secretory component and polymeric IgA formed in vitro were transported poorly (0.1%) compared to polymeric IgA (26%). It was concluded that biliary transport of polymeric IgA requires combination of it with secretory component in the liver. In support of this hypothesis, rabbit IgG anti-rat secretory component antibodies were also transported to bile but normal rabbit IgG was not.

Animals↗