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Biomedical subjects

L Buchner

Publications and source records attributed to L Buchner.

5 recordsLinked to original sources
PubMed1996

Lymphocyte immunophenotype reference ranges in healthy Thai adults: implications for management of HIV/AIDS in Thailand.

Lymphocyte immunophenotype reference ranges for T, B, and NK subsets were determined for healthy adult Thais in a multi-center study in Bangkok. Immunophenotyping was by flow cytometry using lysed whole blood. A standard protocol for flow cytometry instrumentation, reagents and quality control was used to minimize site differences and to facilitate comparison of the Thai reference values to those found for Caucasians in previous studies. Major differences were determined for CD3(T), CD4 (T helper/inducer) and CD16+56 (NK) lymphocyte percentages and CD4 lymphocyte absolute counts. Age trends and sex differences were also observed. Compared to Caucasians, Thais, particularly Thai males, had lower CD3 and CD4 T lymphocyte percentages and absolute numbers whereas the percentage of NK lymphocytes was higher. Heterogeneity attributed to biological variation of CD4 T lymphocyte but not other immunophenotype subset distributions was also observed in a well defined geographic population. This study demonstrates the importance of ethnicity, age, sex and possibly environment as factors that influence distribution characteristics of normal lymphocyte immunophenotype reference values. These observations have important implications for the use of lymphocyte subsets-particularly CD3+ CD4+ T lymphocyte measurements as applied to HIV disease staging, AIDS definition and the overall clinical management of HIV/AIDS in Thailand.

Adult↗
PubMed1994

An optimized method for routine HLA-B27 screening using flow cytometry.

Flow cytometry and monoclonal antibodies are promising tools for HLA-antigen detection. Previous approaches have been hampered by the lack of a carefully standardized system for calibration and sample analysis. A new system for HLA-B27 screening was developed using a FACScan flow cytometer, software for automated calibration and analysis, calibration beads, and the anti-HLA-B27-FITC/anti-Leu4-PE (CD3) monoclonal antibodies. The median fluorescence channel result for the HLA-B27-FITC signal of CD3+ T lymphocytes is compared to a decision marker. Values lower than this threshold are read as HLA-B27 negative and those above are recommended for retesting with the classic microcytotoxicity assay on the presumption of HLA-B27 positivity. The anti-HLA-B27 antibody reacts with all six HLA-B27 subtypes and shows a weaker binding to HLA-B7. The screening test results were compared with those from the microcytotoxicity assay for HLA-typing in studies involving several European centers. The observed sensitivity was 100% (95% Cl:98.6-100) and the specificity was 97.4% (95% Cl: 96.4-98.3). Other performance studies verified the reproducibility and reliability of results obtained with the screening system.

Anticoagulants↗
PubMed1991

[Salmonella enteritidis in chicken eggs].

After an outbreak caused by salmonella enteritidis (SE) of which home-made mayonnaise and remoulade sauce were found to be the cause, SE was detected in ten of the remaining eggs. Subsequently 409 eggs of the next shipment from the same outlet were examined bacteriologically. Of 70 of the eggs examined, SE was found in 5 egg yolk samples and in 3 egg white samples as well as in 2 of 7 pooled shell samples. Five out of 35 pooled whole egg samples comprising a total of 349 eggs were likewise positive for SE. The isolates belonged to the phage types 4 and 7 carried the virulence plasmid pRQ29.

Animals↗
PubMed1980

Cryogenic preservation of rat polymorphonuclear leukocytes.

Rat polymorphonuclear leukocytes (PMNs) were frozen to --196 degrees C, thawed, and tested for functional viability using a variety of criteria, which included: qualitative and quantitative nitroblue tetrazolium assays, fluorometric membrane integrity assays, chemotactic assays, and bactericidal assay. Using these criteria, the survival of rat PMNs obtained from a glycogen-induced peritoneal wash averaged approximately 70% after thawing. The survival of PMNs obtained from rat peripheral blood was greater than 95%. Maximal survival for cryopreservation of these cells frozen in the presence of 10% dimethyl sulfoxide and 5% hydroxyethyl starch was obtained when the cells were cooled at approximately 10 degrees C/min.

Animals↗