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Biomedical subjects

G Bahr

Publications and source records attributed to G Bahr.

14 recordsLinked to original sources
PubMed1994

A longitudinal study of per cent agalactosyl IgG in tuberculosis patients receiving chemotherapy, with or without immunotherapy.

An increased percentage of circulating IgG molecules that lack galactose from the oligosaccharides on the CH2 domain correlates with disease severity in tuberculosis, rheumatoid arthritis and Crohn's disease. We have recently observed that a single injection of 10(9) autoclaved Mycobacterium vaccae given to tuberculosis patients 7 days after the initiation of chemotherapy causes accelerated clinical improvement, and clearance of bacilli from the sputum. We now show that this immunotherapy also causes rapid loss of agalactosyl IgG, detectable within 14-21 days, whereas chemotherapy alone causes agalactosyl IgG to rise further for up to 2 months. There is simultaneous inhibition of the antibody response to lipoarabinomannan, and transient enhancement of the tuberculin skin-test response. These findings are compatible with a shift from antibody production towards increased cell-mediated immunity. The ideal treatment for tuberculosis would supplement a truncated course of chemotherapy with an immunotherapeutic preparation able to down-regulate the Koch phenomenon and replace it with an efficiently bactericidal mechanism. We tentatively postulate that a fall in per cent agalactosyl IgG [%Gal(0)] in tuberculosis patients may be a marker of such a change.

Adolescent↗
PubMed1991

Human heart sarcolemmal sheath antibodies in children with non-suppurative sequelae of group A streptococcal infections: a follow up study.

The kinetics of the human heart sarcolemmal sheath antibody were studied in children with acute rheumatic fever who had no carditis, children with acute rheumatic fever who had carditis and developed rheumatic heart disease, and in children with acute poststreptococcal glomerulonephritis. The children with rheumatic fever and those who developed valvular heart disease were given continuous secondary antistreptococcal prophylaxis. The titre of antibody at onset was significantly higher than that of the controls in children with acute rheumatic fever and carditis and in children with acute poststreptococcal nephritis. The difference in the antibody titre between children with rheumatic fever who had no carditis and controls was not statistically significant. After a mean follow up of three years, however, a high titre was only maintained in children with rheumatic fever who developed valvular heart disease.

Acute Disease↗
PubMed1988

Packing of the 30 nm chromatin fiber in the human metaphase chromosome.

The human genetic material is packed hierarchically within the metaphase chromosome: the DNA molecule together with histone proteins form 11 nm diameter nucleosomes, which are then ordered into the 30 nm thick chromatin fiber. Little is known about the packing of this fiber within the chromosome. We have developed a tracking algorithm with which we followed its path within a three-dimensional reconstruction of a human chromosome computed from a series of electron micrographic projections. Fiber segments were seen to form loops of 100-350 nm diameter. Our observations indicate that these loops--which themselves show no preferred orientation--are organised into regions of roughly 200 nm axial extent.

Chromatin↗
PubMed1984

Adjuvant requirements for protective immunization of mice using a Trypanosoma cruzi 90K cell surface glycoprotein.

A wide range of adjuvants including alhydrogel, saponin, Corynebacterium parvum, DDAB, Pfizer CP-20,961, oil adjuvants and several MDP analogues have been compared for their adjuvant activity in protecting mice against lethal Trypanosoma cruzi infection following immunization with a T. cruzi 90K cell surface glycoprotein. Only saponin was found to be effective. Promotion did not correlate with the ability to promote a particular Ig isotype; however, saponin was unique in its ability to promote cell-mediate immunity against the 90K glycoprotein.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1983

Homogeneously staining regions and double minutes in a human cell line: chromatin organization and DNA content.

Homogeneously staining regions (HSR) and double minutes, two novel chromosome abnormalities, are believed to represent sites of gene amplification. The basic organization of chromatin in an HSR in a human neuroblastoma cell line was shown, by electron microscopy, to be similar to that in a normal chromosome. Double minutes from another human neuroblastoma cell line were found, by dry mass determination, to contain an average of 1.41 X 10(-14) g DNA. This quantity corresponds to 6.38 X 10(3) kilobase DNA per double minute.

Cell Line↗
PubMed1980

A simplified immunoenzyme antigen binding technique as an approach for immunodiagnosis.

A simple immunoenzyme technique is described in which the enzyme beta-galactosidase of E. coli (Z) is used as a marker. The principle of the test is based on the ability of the cells to bind the antigen. Conditions of the assay using Z both as the antigen and marker are described. As a screening technique, conditions are defined at limited antigen concentrations when binding is not directly proportional to the number of cells present. Hence, drops of blood can be used directly for detection of an immune response without counting the cells. Furthermore, treatment of whole blood with ethanol was shown to (a) increase the binding capacity and (b) allow the storage of specimens for weeks without any loss of activity. With human hydatid fluid (HHF) antigens conjugated to Z as a model, it was possible to detect the immune response of rabbits injected with HHF. The method is simple, requires no sophisticated equipment and can be used in large scale epidemiological surveys.

Animals↗