Influence of cold exposure on catecholamine depleting actions of hydroxylase inhibitors.
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Adaptation, Physiological↗
Biomedical subjects
W C Chan
Publications and source records attributed to W C Chan.
Diffuse membranous glomerulonephritis in children.
Nine cases of diffuse membranous glomerulonephritis detected among 90 renal biopsies from children with persistent proteinuria and one necropsy case of a young child who died of chronic membranous glomerulonephritis with uraemia were studied by a variety of techniques. Clinical presentation varies within this single morphological entity and the response to steroid therapy is not yet predictable on either clinical or morphological criteria. Correlation is demonstrated between therapeutic responses and the degree of selectivity of the proteinuria which was determined by studying the relative protein clearances with an immunochemical technique.
Biopsy↗
The immunologic evaluation of the Yucheng children.
The immunologic effects of in utero exposure to polychlorinated biphenyls (PCBs)/polychlorinated dibenzofurans (PCDFs) were evaluated in the Yucheng children in this study. The study subjects consisted of 105 Yucheng children and 101 control children. The Yucheng children were born, between July 1978 and June 1987, to women who had exposed to high dose of PCBs/PCDFs through consumption of contaminated rice bran oil in 1978-1979. These children had been reported to have higher frequencies of bronchitis than their controls in the first six months of life, and higher frequencies of respiratory tract and ear infection in a 6-year follow-up. The low resistance of the Yucheng children to infection suggested that their immune function was suppressed by the PCBs/PCDFs they had exposed to in utero. In the summer and fall of 1995, a thorough physical examination and blood draw were performed on the study children. The Yucheng children were reported by their parents to have higher frequencies of influenza attacks than the control children during the six months prior to the examination. The frequencies of other symptoms were similar between the two groups. The serum levels of various immunoglobulins were similar between the two groups. Fifty-one serum samples, 29 of Yucheng and 22 of control children, were available for cell-mediated immunologic analysis. The percentages of various T cell markers, CD3, CD4, and CD8, and B cell and NK cell markers were not different between the Yucheng and the control children. No dose-response relationship was found between 27 Yucheng children's serum PCB/PCDF levels and any of their immunologic markers. WE concluded that 16 years after the Yucheng incident, Yucheng children exposed to high dose of PCBs/PCDFs in utero did not show, with the serum immunologic marker analyses, suppressed immunity when compared to their controls. To explain the consistent higher frequencies of upper respiratory tract infection in the Yucheng children, immune functional tests such as delayed hypersensitive skin reaction, in vitro lymphocyte proliferation, and antibody synthesis following immunization may be necessary.
Adolescent↗
Combinatorial mutagenesis analysis of residues in the channel constriction loop L3 and neighbouring beta-strands in the LamB glycoporin of Escherichia coli.
Members of the LamB family of sugar-selective porins (glycoporins) are beta-barrel proteins in the outer membrane of Gram-negative bacteria. To study the determinants of structure and sugar selectivity, 68 non-identical single amino acid substitutions were introduced into the stretch of sequence consisting of residues 106 through 125 in Escherichia coli LamB. This region includes all bar one residue of the channel constriction loop L3 and extends into the transmembrane beta 6 strand in the LamB structure. Mutants were assayed for dextrin utilization, starch binding, A binding, monoclonal antibody binding and for qualitative changes in protein expression. The importance of the L3 amino acids was emphasized by the observation that only four residues permitted a majority of neutral substitutions. Changes to the channel constriction zone strongly affected sugar binding yet no single amino acid change of residues exposed to the channel lumen caused a complete defect in maltodextrin utilization (i.e. were still Dex+). Substitutions in the L3 loop did not affect phage lambda binding, except one change at residue 122, nor changed recognition by anti-LamB antibodies specific for surface epitopes, consistent with the lack of a role of L3 residues in surface receptor function. In marked contrast, four substitutions in transmembrane strand beta 5 resulted in a Dex- phenotype and gross changes in protein properties, indicating the significance of beta 5 in the architecture of LamB.
Amino Acid Sequence↗
Comparative p53 mutational spectra in aerodigestive tract tumors in Hong Kong Chinese patients.
The p53 mutations in colorectal, esophageal and lung carcinomas from Hong Kong were studied previously. The availability of mutation data for these cancers in one geographical region prompted investigations into special features of these p53 alterations. Mutations in codons 175, 176, 248 and 273 accounted for 35% of all mutations detected. A hot spot at codon 176 observed in esophageal carcinomas was not detected in any of the other aerodigestive tract tumors studied and appeared to be uniquely restricted to Chinese esophageal cancers. Other unique mutation sites, and a notably higher frequency of insertions and deletions in each of these cancers, were also detected in Chinese patients as compared to Caucasians.
Asian People↗