Biomedical subjects

Q Yang

Publications and source records attributed to Q Yang.

At least 505 records · Page 28Linked to original sources

PubMed1989

Hyperkinetic hemodynamic pattern in some borderline hypertension: differential responses to alpha and beta agonists.

Twenty eight male borderline hypertensive patients(BH), mean age of 19.72 +/- 2.80 years, were studied and matched with 28 normal controls (NC). Alpha-adrenergic responsiveness was estimated with DPD15 (the dosage of neosynephrine required for an increase of diastolic pressure of 15mmHg); beta-adrenergic responsiveness with CD25 (the dosage of isoproterenol required for an increase of heart rate of 25 beats/minute). Using CD25 of 1.0ug (mean of the NC), the BH could be subdivided into two specific types: 13 patients (46%) whose CD25 less than 1.0 ug, 0.50 +/- 0.24 (m +/- SD) had a hyperkinetic pattern; the remaining 15 patients (54%) whose CD25 greater than 1.0ug, 1.76 +/- 0.32 (m +/- SD), had a normokinetic one. Values of DPD15 of the two types were comparable. Cardiac index (CI, L/min/M2) and total peripheral resistance (TPR, dynes/sec/cm-5) of the two types manifested significant differences, both p less than 0.001. When plotting CI and TPR versus CD25, good correlations were obtained. In the BH group, the coefficient r was -0.73 between CI and CD25, + 0.70 between TPR and CD25; correlations were poor when plotting versus DPD15. Similar correlations also happened in the NC. The present study suggests that coexistence of two different hemodynamic patterns may be due to the imbalance resulted from the interaction between alpha-adrenergic responsiveness and beta-adrenergic responsiveness.

Adrenergic alpha-Agonists↗

PubMed1989

[Application of Pirkle-type chiral column to the resolution of enantiomeric drugs: resolution and identification of alpha-naphthyl isocyanate derivatives of alprenolol and some other beta-blockers].

alpha-Naphthyl isocyanate (NI) as a derivatizing agent to separate several beta-blockers was described. This procedure is simple, rapid and gives good resolution. Experiments with NI derivatives of alprenolol showed that the isocyanate group reacted with the amino group on the analyte to form urea under mild conditions and with the hydroxyl group to form carbamate under relatively vigorous conditions. The results also indicated that the derivatized reactions is 1:1 between NT and analytes.

Adrenergic beta-Antagonists↗

PubMed1988

Immobilization of phospholipid vesicles and protein-lipid vesicles containing red cell membrane proteins on octyl derivatives of large-pore gels.

For improved immobilization of phospholipid vesicles and protein-lipid vesicles (cf. Sandberg, M., Lundahl, P., Greijer, E. and Belew, M. (1987) Biochim. Biophys. Acta 924, 185-192) and for chromatographic experiments with vesicles containing membrane protein, we have prepared octyl sulfide derivatives of the large-pore gels Sephacryl S-1000 and Sepharose 2B with ligand concentrations up to 14 and 5 mumol/ml gel, respectively. The Sephacryl derivatives allowed higher flow rates, gave higher rates of adsorption and showed equally high or higher capacities than the Sepharose adsorbents. 'Small', 'medium' and 'large' vesicles of radii approx. 20, 50 and 100 nm showed distribution coefficients on Sephacryl S-1000 of 0.7, 0.5 and 0.05, respectively and could be immobilized on octyl sulfide-Sephacryl S-1000 in amounts corresponding to 110, 40 and 20 mumol of phospholipids per ml gel, respectively. 'Small' vesicles became absorbed onto this gel at a rate of 1.5 mumol of phospholipids per min per ml gel until 60 mumol of phospholipids had become immobilized, whereas the initial adsorption rate was about 0.4 mumol.min-1.ml-1 on octyl sulfide-Sepharose 4B (see reference above) and on octyl sulfide-Sepharose 2B. Lower ligand concentrations gave lower capacities for 'small' vesicles. When vesicles entrapping calcein were immobilized on octyl sulfide-Sephacryl S-1000 some calcein was released during the adsorption process. For 'small' and 'medium' vesicles, respectively, the leakage was 75 and 25% at a ligand concentration of 14 mumol/ml but only 3 and 2% at 5 mumol/ml. The internal volumes of immobilized 'small' and 'medium' vesicles were estimated at 0.97 and 2.9 microliters per mumol of phospholipid by determination of entrapped calcein, which could indicate vesicle radii 20 and 50 nm, respectively. The total volumes of immobilized 'medium' lipid vesicles and 'medium' protein-lipid vesicles containing integral membrane proteins from human red cells, were estimated at 2.9 and 2.0 microliters/mumol, respectively, by chromatography of D- and L-[14C]glucose and calcein on the octyl sulfide-Sephacryl S-1000 column before and after immobilization. These volumes are roughly consistent with the internal volume of the vesicles. A zone of D-glucose eluted 90 microliters later than a zone of L-glucose on a 4- or 5-ml column of octyl sulfide-Sephacryl S-1000 with immobilized 'medium' protein-lipid vesicles containing the glucose transporter from human red cells, probably since part of the internal vesicle volume was accessible to the D-glucose but not to the L-glucose. This indicates that the glucose transporter was active in the immobilized vesicles.(ABSTRACT TRUNCATED AT 400 WORDS)

Blood Glucose↗

PubMed1988

Expression of a collagen gene in mesenchyme lineages of the Strongylocentrotus purpuratus embryo.

We have previously described cloning of an exon of a sea urchin collagen gene and shown that its expression is temporally regulated during embryogenesis, beginning during blastula formation. We have now localized the protein encoded by the gene and the sites of its mRNA synthesis in the developing embryo. Antibody to a synthetic peptide reacts with a 208,000 Mr protein that is digestible by collagenase. Fractionation of pluteus stage embryos demonstrates that the protein is localized primarily with cells that form the syncytium of primary mesenchyme that elaborates the larval endoskeleton; furthermore, immunofluorescence localizes the epitope to the periphery of the endoskeleton in situ. Transcripts of the gene accumulate only in mesenchyme cells, especially those of the primary mesenchyme lineage. Measurements of absolute transcript abundance show that collagen mRNA is present in blastula primary mesenchyme cells at 600-700 copies per cell and at about fourfold lower amounts in other mesenchyme cells.

Animals↗

PubMed1988

The aging of China's population: perspectives and implications.

"China's efforts to accelerate the pace of modernization emphasize the promotion of economic development and the reduction of its population growth through the adoption of a one-child per family policy. However, that policy has implications for the eventual aging of the country's population. This article reviews the changes in the status of the elderly, explores the changes in size of the elderly population, and various related social and policy implications." Topics considered include socioeconomic changes, underlying population dynamics, the current situation of the elderly, some international comparisons, implications of aging, planning for support of the elderly, health care, living arrangements and family support, retirement, and the status of the widowed, divorced, and unmarried in the elderly population.

Adult↗

PubMed1988