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Biomedical subjects

H Shan

Publications and source records attributed to H Shan.

23 records · Page 2Linked to original sources
PubMed1990

Heavy-chain class switch does not terminate somatic mutation.

We studied the H-chain class switch rearrangement in four groups of clonally related B cell hybridomas, to test the hypothesis that class switch terminates somatic mutation in a B cell. Using switch region-specific probes in Southern blot analysis individual mu-gamma switch rearrangement events can be distinguished. We show that clonally related IgG-producing hybridomas that differ by mutations often share a common switch rearrangement. This indicates that class switch in these cells did not terminate somatic mutation.

Animals↗
PubMed1990

Anti-DNA antibodies from autoimmune mice arise by clonal expansion and somatic mutation.

The proximate cause of autoantibodies characteristic of systemic autoimmune diseases has been controversial. One hypothesis is that autoantibodies are the result of polyclonal nonspecific B cell activation. Alternatively, autoantibodies could be the result of antigen-driven B cell activation, as observed in secondary immune responses. We have approached this question by studying monoclonal anti-DNA autoantibodies derived from unmanipulated spleen cells of the autoimmune MRL/lpr mouse strain. This analysis shows that anti-DNAs, like rheumatoid factors (19), are the result of specific antigen-driven stimulation. In addition, correlation of sequences with fine specificity shows that: (a) somatic mutations can cause specificity for dsDNA and that such mutations are selected for; (b) arginine residues play an important role in determining specificity; and (c) anti-idiotypes that recognize the majority of anti-DNA are probably not specific for any one family of V regions.

Amino Acid Sequence↗
PubMed1990

[The anti-hemorrhagic shock of acupuncture on neiguan and its effect on the cardial pump function and the blood viscosity].

The purpose of this paper is to study and analyse the effects of the cardial pump function and the blood viscosity on rabbits with hemorrhagic shock by puncturing Neiguan. In the experiment 30 rabbits were divided into the electroacupuncture (EA) group and the control group, each group was 15 rabbits. The cardial pump function, the blood pressure and the blood viscosity were recorded during normalize, shock, and EA. The results were as following. 1. The blood pressure of the rabbits which were in hemorrhagic shock was raised by needling Neiguan. MAP was raised from 43 +/- 8 to 87 +/- 15 mmHg (p less than 0.001). 2. The cardial pump function were reinforced by needling Neiguan. SV was increased from 0.41 +/- 0.46 (before EA) to 0.73 +/- 0.12 ml (p less than 0.0001). CO, SI, CI. and WL were improved in a certain degree with difference significant. In the EA group the each index of the cardial pump function was higher than that of the control group. There was statistical significant between the two groups. 3. Needling Neiguan, the blood viscosity was tending to normality. The blood plasma viscosity was increased. There was significant difference (p less than 0.05). These results suggest that needling Neiguan may protect the cardial pump function, raise the blood pressure, play a positive role during anti hemorrhagic shock.

Acupuncture Points↗
PubMed1988

Biological characterization of a simian immunodeficiency virus-like retrovirus (HTLV-IV): evidence for CD4-associated molecules required for infection.

We have analyzed a number of biological features of HTLV-IV, a retrovirus indistinguishable from a macaque isolate of simian immunodeficiency virus (SIV), and compared this virus with several strains of human immunodeficiency virus type 1 (HIV-1). Although HTLV-IV was found to be similar to HIV-1 in its tropism for CD4+ lymphocytes, its effects on CD4 expression and the ability of its externalized envelope molecule to form a complex directly with the CD4 molecule, a number of striking differences were noted. Unlike with HIV-1, the range of cells susceptible to HTLV-IV infection and syncytia formation was restricted to a subset of CD4+ cell lines, particularly those that coexpressed CD4 with human leukocyte antigen (HLA) class II antigens. An analysis of the patterns of HTLV-IV infection with B x T somatic cell hybrids indicated that for this virus, molecules in addition to CD4 were probably required to facilitate infection and cell fusion. Additional studies of HTLV-IV infection of Sup-T1 cells, which are exquisitely sensitive to cytopathic effects induced by HIV-1, demonstrated that HTLV-IV infection could occur in the absence of cytopathic effects and, remarkably, with minimal or no downmodulation of the CD4 molecule from the cell surface. The failure of HTLV-IV infection to reduce the expression of several CD4 epitopes suggested that the HTLV-IV envelope produced by Sup-T1 cells was altered in its ability to interact with or bind to CD4. Additional differences were also noted in the size of the transmembrane envelope molecule of HTLV-IV produced by Sup-T1 cells, indicating that cell-specific alterations in processing of the HTLV-IV envelope occurred during the production of virus in this cell line. Understanding the basis for these biological differences between HTLV-IV and the HIV-1 viruses may help to elucidate more general mechanisms for pathogenesis of other members of the SIV and HIV families of retroviruses.

Animals↗