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Biomedical subjects

Q Meng

Publications and source records attributed to Q Meng.

137 records · Page 8Linked to original sources
PubMed1991

Age-related differences in the metabolism of proteoglycans in bovine articular cartilage explants maintained in the presence of insulin-like growth factor I.

Articular cartilage explants from bovine calf and steer were cultured for up to 19 days in medium with or without 20% fetal bovine serum (FBS) or insulin-like growth factor I (IGF-I). Lower concentrations of IGF-I were required for maximal stimulation of PG synthesis in calf than in steer. In calf, but not in steer, IGF-I was as effective as 20% FBS in stimulating PG synthesis. The stimulation by IGF-I or FBS was not accompanied at either age by alterations in the composition of the aggregating PGs nor by changes in the proportions of CS-rich and CS-poor PG subpopulations. In calf, IGF-I and FBS did not markedly alter the rate of turnover of either the 35S-PGs synthesized in vitro or the unlabeled PGs. In steer, explants cultured in the absence of IGF-I or FBS exhibited very fast rates of turnover and depletion of matrix PG with time; IGF-I and FBS were both effective in reducing the turnover rate of 35S-PGs and unlabeled PGs and in preventing PG depletion.

Aging↗
PubMed1990

Estimating starch availability and protein degradation of steam-flaked and reconstituted sorghum grain through a gas production technique.

Five steam-flaked sorghum grain (SFSG) samples with bulk densities of 476, 412, 347, 309 and 283 g/liter made by adjusting tension between mill rollers and three reconstituted sorghum grain (RSG) samples with reconstitution times of 10, 20 and 30 d and a control sample were analyzed for gas production kinetics (rumen liquor fermentation) and enzymatic glucose release (amyloglucosidase). Protein degradation was estimated from 6-h gas production and residual ammonia in the liquid. Gas production followed first-order kinetics (r2 greater than .98; P less than .01) and was used to describe rate and extent of digestion kinetics. Rate of gas production increased as processing degree increased. The magnitude of increase in gas production, however, was much less for RSG than for SFSG. Linear relationships were observed between enzymatic glucose release and the gas production rate constant k as well as gas production at 4,6 and 8 h (r2 greater than .98; P less than .01). Protein degradation decreased with processing degree of SFSG but increased with reconstitution time. A technique based on 6-h gas production and residual ammonia in the liquid is proposed to estimate both ruminal starch availability and ruminal protein degradability for processed sorghum grain.

Animal Feed↗
PubMed1990

[Serum isoforms of creatine kinase MM (MM3/MM1 ratio) in the diagnosis of acute myocardial infarction].

The reliability of serum MM3/MM1 ratio as a marker for AMI was evaluated in 81 consecutive coronary-care admission. Of these, 62 patients were diagnosed as definite infarction and 19 patients as angina, using WHO criteria. The MM3/MM1 ratio in the admission serum sample was 1.85 +/- 2.01 in 62 patients with definite infarction; in contrast, the MM3/MM1 ratio was 0.24 +/- 0.14 in 19 patients with angina (P less than 0.01 for MI group vs angina group). Among the AMI patients admitted within 12 h after onset, the diagnostic accuracy of the ratio MM3/MM1 was higher than CK, CK-MB, LDH, LD1/LD2 and GOT and similar to Mb in the initial serum samples. It seems that the MM3/MM1 ratio was a better enzyme marker than the others in the early stage of AMI, especially before 12 h.

Adult↗
PubMed1990

Investigation of anti-HCV in 391 serum samples in China.

391 serum samples from healthy blood donors, HBsAg positive blood donors and patients with different kinds of liver diseases in northern China were tested for anti-HCV by ELISA. Of the healthy donors, 4.6% (7/151) were anti-HCV positive; of the HBsAg positive donors, 32.4% (24/74) were positive; and of the liver disease patients, 5.4% (9/166) were positive. Among the 24 cases of HBV-HCV double infection, 10 were assayed for serum ALT level. 40% (4/10) of them were abnormal. The causes of the surprisingly high rate of HCV infection, both in healthy donors and in HBsAg positive donors, were discussed. This is the first report on the distribution of anti-HCV in certain population in China.

Adult↗
PubMedDate not supplied

Tubulin genes in the algal protist Euglena gracilis.

Alpha- and beta-tubulin cDNA were selected from a Euglena lambda gt11 expression library, recloned and either sequenced (alpha-tubulin cDNA) or hybridized to Euglena RNA and DNA (alpha- and beta-tubulin cDNA). RNA for hybridization was extracted at 30 minute intervals after flagellar amputation and quantitated for cDNA binding. Unlike previous reports on most other flagellates, no net increase in either alpha- or beta-tubulin RNA could be detected during regeneration--suggesting steady state or constitutive tubulin RNA synthesis. Incubation of the cDNA with genomic DNA after restriction digestion produced patterns of hybridization consistent with the presence of one to two kinds each of the alpha- and beta-tubulin genes. The deduced amino acid sequence of the alpha-tubulin cDNA was more than 90% identical to the alpha-tubulins of Trypanosoma, Chlamydomonas, Naegleria, Tetrahymena and higher plants. The carboxy terminus of the alpha-tubulin cDNA and the previously sequenced beta-tubulin of Euglena showed greatest identity to the carboxy terminus of the tubulins from Trypanosoma brucei. The sequence data for alpha- and beta-tubulins of Euglena provides direct evidence for the similarity of two gene products from euglenas and trypanosomes and adds support to earlier suggestions that these organisms are phylogenetically related.

Amino Acid Sequence↗
PubMedDate not supplied

Eosinophil development and bone marrow and tissue eosinophils in atopic asthma.

BACKGROUND: Eosinophils develop from bone marrow (BM) progenitors, and interleukin-5 (IL-5) and eotaxin may act in expansion and mobilisation of BM eosinophils in asthma. METHODS: We have examined phenotypic changes as CD34+ cells develop to the eosinophil lineage in vitro, and have evaluated BM eosinophils from asthmatic and control subjects for expression of the eotaxin receptor, CCR3. RESULTS: Acquisition of receptors for IL-5 and CCR3 was an early event in eosinophil development. There were increased CD34+ cells, and mature and immature CCR3+ eosinophils in BM from asthmatics. CONCLUSION: These data suggest that IL-5 may act early in eosinophil development, and that eotaxin has the capacity to mobilise a BM eosinophil pool in asthma.

Antigens, CD34↗
PubMedDate not supplied

Mechanisms of T cell peptide epitope-dependent late asthmatic reactions.

Short peptide sequences corresponding to T cell epitopes have been identified in the major cat allergen Fel d 1. In order to directly activate allergen-specific T cells in cat-allergic asthmatic individuals, peptides were administered by intradermal injection. Subsequently, a proportion of subjects experienced a delayed reduction of airway calibre manifested as a decrease in FEV(1). Changes in lung function occurred approximately 3 h after peptide injection, peaked at 6 h and resembled an isolated late asthmatic reaction (LAR). Using molecular tissue typing techniques, it was determined that many of the individuals experiencing isolated LAR expressed particular HLA-DR molecules. These molecules were shown in subsequent experiments to bind individual peptides within the preparation and thus to activate T cells in a major histocompatibility complex (MHC)-restricted fashion. The precise mechanisms whereby MHC-restricted activation of allergen-specific T cells gives rise to bronchoconstriction are currently under investigation.

Animals↗
PubMedDate not supplied

Eosinophils and eosinophil-associated cytokines in allergic inflammation.

Eosinophils are major effector cells in allergic tissue reactions. Their capacity to synthesize and store cytokines, particularly Th2-type cytokines, which may have autocrine effects such as increased cell survival in tissues, is of particular current interest. We have shown that eosinophils infiltrating the site of human cutaneous late-phase reactions (LPR) express mRNA and protein product for IL-4 and IL-5. Stimulation of peripheral blood eosinophils in vitro with either IgG or sIgA produces time-dependent induction of IL-4 and IL-5 transcription, indicating that mature cells may undergo local cytokine synthesis. We also demonstrated that bronchial biopsies from patients with both atopic and non-atopic (intrinsic) asthma express IL-4 and IL-5 mRNA which mainly co-localized to T cells, although clear hybridization signals were also obtained with eosinophils and mast cells. On the other hand, immunoreactivity for the corresponding protein was detectable predominantly in eosinophils and mast cells; a finding believed to reflect granule storage of cytokines. We also studied the resolution of the cutaneous LPR. Apoptosis of eosinophils persisted slightly longer than neutrophils in the tissues. The eventual decline in both neutrophil and eosinophil numbers followed on from the peak of the LPR. This was associated with terminal-deoxynucteotidyl-transferase-mediated nick and labelling positive (TUNEL+) (apoptotic) cells with the subsequent removal of apoptotic neutrophils and eosinophils by tissue macrophages. Thus, IL-4 and IL-5 production by eosinophils may amplify local allergic inflammatory responses and, in the case of IL-5, may prolong local tissue survival. However, in the allergen-induced LPR, inflammation rapidly resolves, possibly through the initiation of programmed cell death and phagocytosis of apoptotic cells by macrophages.

Asthma↗