Biomedical subjects

Yi Shen

Publications and source records attributed to Yi Shen.

39 records · Page 3Linked to original sources

PubMed2002

Endogenous pro- and anti-inflammatory cytokines differentially regulate an in vivo humoral response to Streptococcus pneumoniae.

Proinflammatory cytokines play a critical role in innate host defense against extracellular bacteria. However, little is known regarding the effects of these cytokines on the adaptive humoral response. Mice injected with a neutralizing anti-tumor necrosis factor alpha (TNF-alpha) monoclonal antibody (MAb) at the time of primary immunization with intact Streptococcus pneumoniae (strain R36A) showed a substantial reduction in both the primary immunoglobulin G (IgG) response specific for the cell wall protein, pneumococcal surface protein A (PspA), as well as in the development of PspA-specific memory. In contrast, anti-TNF-alpha MAb injected only at the time of secondary immunization with R36A failed to alter the boosted anti-PspA response. TNF-alpha was required only within the first 48 to 72 h after primary immunization with R36A and was induced both by non-B and non-T cells and by lymphoid cells, within 2 to 6 h after immunization, with levels returning to normal by 24 h. Thus, the early innate release of TNF-alpha was critical for optimal stimulation of the subsequent adaptive humoral response to R36A. Additional proinflammatory (interleukin 1 [IL-1], IL-6, IL-12, and gamma interferon [IFN-gamma]) as well as anti-inflammatory (IL-4 and IL-10) cytokines were also transiently induced. Mice genetically deficient in IL-6, IFN-gamma, or IL-12 also showed a reduced IgG anti-PspA response of all IgG isotypes. In contrast, IL-4(-/-) and IL-10(-/-) mice immunized with R36A showed a significant elevation in the IgG anti-PspA response, except that there was decreased IgG1 in IL-4(-/-) mice. In this regard, a marked enhancement in the induction of proinflammatory cytokines was observed in the absence of IL-10, relative to controls. Ig isotype titers specific for the phosphorycholine determinant of C-polysaccharide were similarly regulated, but to a much more modest degree. These data suggest that proinflammatory and anti-inflammatory cytokines differentially regulate an in vivo protein- and polysaccharide-specific Ig response to an extracellular bacteria.

Adhesins, Bacterial↗

PubMed2002

Development and psychometric tests of a Chinese version of the SF-36 Health Survey Scales.

OBJECTIVE: To develop and evaluate scaling and scoring assumptions, and the reliability and the validity of a Chinese version of the SF-36 scales. METHODS: A multi-stage mixed sampling procedure was used to select a representative sample of the general population. The sample size was 1 000 households. All family members of a selected household, aged 18 and older, completed a survey by self-administration. Formal psychometric methods for testing assumptions underlying item scoring and scale construction were used according to the standard procedure of the IQOLA Project. RESULTS: Of the 1 985 collected questionnaires, 1 972 were qualified. Of them, 1 688 (85.6%) were respondents. 1 316 respondents answered all 36 items, while the remaining (372 respondents) answered with one or several missing responses. Among the non-respondents, 65.5% were illiteracy or quasi-illiteracy. The assumption of equal intervals was violated for the VT and MH scales. The recoded item values were used to calculate scale scores. The clustering and ordering of the item means were approximately the same as that of the source version and other two Chinese versions. The items in each scale had similar standard deviations except those in the PF, BP, SF scales. The correlations between an item and its hypothesized scale were identical for all except the SF and VT scales. The scaling success rates of convergent validity were 0% for the SF scale, 75% for the VT scale, and 100% for the other six scales. The scaling success rates of discriminat validity ranged from 87.5% to 100% for all scales except for the SF scale. The Cronbach' alpha coefficients of internal consistency reliability ranged from 0.72 to 0.88, which were satisfactory for group comparison except 0.39 for the SF scale and 0.66 for the VT scale. The two-weeks test-retest reliability coefficient ranged from 0.66 to 0.94. Factor analysis identified two principal components: a "physical" factor and a "mental" factor. Taken together, these two factors could be used to explain 56.3% of the total variance. CONCLUSION: The Chinese version of the SF-36 Health Survey Scale has achieved conceptual equivalence and satisfied the psychometric scaling assumptions well enough to warrant wide use in China. Known-groups validity will give more meaningful evidences of the validity of the Chinese SF-36 scales.

Asian People↗

PubMed2002

[Discussion of the application of three-point interaction principle to the phenylglycine racemic compound in IR spectrometry and its enantiomers separation in HPLC].

AIM: To discuss the relationship between the three-point interaction principle in the stereoselective separation of chromatography and applying this principle to survey the infrared spectrometry of racemate. METHODS: In proving the applicability of the three-point interaction principal in IR spectrometry, a special case was found that phenylglycine did not obtain enantioselective separation on the chiral column but its IR spectrometry still obey this principle and explained such special case by experiment. RESULTS: After an equal quantity of solid crystal of d-phenylglycine and l-phenylglycine were mixed and ground for several minutes, they transformed to racemic compound. X-powder diffraction also confirmed this fact. CONCLUSION: The three-point principle was relatively reliable when it was used in the enantioselective chromatography separation and the IR spectrometric analysis. The reason of the fact that phenylglycine was not separated by chiral column can be explained by the fact that the acting force between the three polarity groups in the enantiomers is so strong that they can not form the instantaneous diastereoisomer with the chiral column, it was agreeable with the phenomenon that racemic mixture easily became racemic compound only by simply grinding the mixture in IR spectrometric experiment.

Chromatography, High Pressure Liquid↗