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Biomedical subjects

H Ding

Publications and source records attributed to H Ding.

At least 163 records · Page 9Linked to original sources
PubMed1995

P-selectin and vascular cell adhesion molecule 1 mediate rolling and arrest, respectively, of CD4+ T lymphocytes on tumor necrosis factor alpha-activated vascular endothelium under flow.

This report examines the adhesive interactions of human CD4+ T lymphocytes with tumor necrosis factor alpha-activated human endothelial cell monolayers in an in vitro model that mimics microcirculatory flow conditions. Resting CD4+ T cell interactions with activated endothelium consisted of initial attachment followed by rolling, stable arrest, and then spreading and transendothelial migration. P-selectin, but not E-, or L-selectin, mediated most of this initial contact and rolling, whereas beta 1-integrins (alpha 4 beta 1), interacting with endothelial-expressed vascular cell adhesion molecule 1, participated in rolling and mediated stable arrest. In contrast, beta 2-integrins were primarily involved in spreading and transmigration. These findings highlight an important role for P-selectin and suggest discrete functions for beta 1- and beta 2-integrins during lymphocyte recruitment to sites of immune-mediated inflammation.

Animals↗
PubMed1995

Plasma levels of beta-endorphin, leucine enkephalin and arginine vasopressin in patients with essential hypertension and the effects of clonidine.

In order to investigate the changes of endogenous opiate systems in hypertension and their possible role in the pathogenesis in hypertension, we measured plasma concentrations of beta-endorphin, leucine-enkephalin, neurotension, arginine vasopressin, plasma renin activity and angiotensin II by radioimmunoassay in 60 normal persons and 120 patients with essential hypertension. The results showed that the patient group had lower levels of beta-endorphin and leucine enkephalin (P < 0.001), higher levels of arginine vasopressin, plasma renin activity and angiotensin II (P < 0.01, P < 0.05 and P < 0.05, respectively), and normal level of neurotensin, as compared with those in normal group. Plasma levels of leucine-enkephalin was correlated negatively to the mean artery pressure (r = -0.196, P < 0.05). Plasma level of arginine vasopressin was correlated to the duration of the hypertension (r = 0.216, P < 0.05). After 150 min and 14 days of treatment with clonidine, plasma levels of beta-endorphin, leucine-enkephalin increased significantly (< 0.01) and correlated negatively with the decrease of the mean artery pressure (r = -0.340 and r = -0.436 at 150 min, r = -0.369 and r = -0.441 on the 14th day, respectively, P < 0.01). Plasma renin activity and angiotensin II decreased significantly (P < 0.05 and P < 0.01). Arginine vasopressin and neurotensin did not change significantly. After intravenous administration of opiate antagonist-naloxone, the blood pressure and heart rate increased significantly (P < 0.01). The results suggested that the changes of endogenous opioids may be involved in the pathogenesis of hypertension and in the antihypertensive action of clonidine.

Angiotensin II↗
PubMed1995

Altered physiology and action of insulin-like growth factor 1 in skeletal muscle in chronic renal failure.

Chronic renal failure is associated with abnormalities of skeletal muscle that include reduction in size, fibrosis, protein depletion, and functional disorders. These disorders may be caused by several factors, including protein-calorie malnutrition, acidemia, and superimposed illnesses. However, animal research suggests that these abnormalities may occur with chronic renal failure per se in the absence of the above complications. Insulin-like growth factor 1 (IGF-1) is an anabolic hormone that, in skeletal muscle, stimulates intracellular amino acid and glucose transport and protein synthesis, suppresses protein degradation, and causes hypertrophy. In chronic renal failure, there is evidence for inhibition of the actions of IGF-1. Studies in humans with chronic renal failure given a subcutaneous injection of recombinant human IGF-1 (rhIGF-1) indicate that the rhIGF-1 induced acute suppression of plasma amino acids, insulin, and C peptide is impaired. In skeletal muscle of rats with chronic renal failure, we observed reduced IGF-1 and IGF-1 mRNA levels, resistance to the rhIGF-1-induced suppression of protein degradation, and stimulation of protein synthesis, increased IGF-1 receptor mRNA and IGF-1 receptor number and impaired receptor tyrosine kinase activity. These findings suggest that in skeletal muscle in chronic renal failure there are several abnormalities in the physiology of IGF-1 and the sensitivity to IGF-1. It is possible that these alterations contribute to the disorders of skeletal muscle structure and function in chronic renal failure. Notwithstanding these abnormalities, repeated subcutaneous injections of rhIGF-1 in malnourished patients undergoing continuous ambulatory peritoneal dialysis led to strongly positive nitrogen balance that was sustained for the 20 days of study.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Effects of recombinant human insulin-like growth factor 1 on renal handling of phosphorus, calcium, and sodium in normal humans.

The effects of insulin-like growth factor 1 (IGF-1) on renal handling of phosphorus, calcium, and sodium were evaluated in eight healthy men while they lived in a clinical research center for slightly more than 5 days. Subjects received a continuous intravenous infusion throughout the study of 0.45% saline and 2.5% d-glucose at 50 mL/hr (group 1, four subjects) or 150 mL/hr (group 2, four subjects). Recombinant human IGF-1 (rhIGF-1), 60 micrograms/kg body weight, was injected subcutaneously three times daily for 10 doses from day 2 until the beginning of day 5. After commencing the rhIGF-1 injections, there was a marked decrease in the fractional excretion of phosphorus in both groups that was sustained throughout the study. Urine phosphorus excretion also decreased significantly on days 2 to 5 in group 1 and on day 2 in group 2. In group 1, the fractional excretion of calcium decreased on day 2; urine calcium did not change. The fractional excretion of sodium decreased on days 2 and 4; urine sodium decreased significantly only on day 2. In group 2, the fractional and absolute urine excretion of calcium did not change. Fractional sodium excretion was not altered, and urine sodium increased only on day 5. The average serum phosphorus, calcium, and sodium did not change from baseline in groups 1 or 2. The pattern of the circadian rhythms for serum concentrations, urine excretion, and fractional excretion of phosphorus and calcium did not appear to be affected by the rhIGF-1 injections.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Effects of insulin-like growth factor I on phosphate transport in cultured proximal tubule cells.

In vivo, proximal tubule cells are exposed to insulin-like growth factor I (IGF-I) that is present in serum or in proximal tubule fluid. For example, in the nephrotic syndrome, proximal tubule fluid contains IGF-I at biologically meaningful concentrations in association with IGF-binding protein-2 (IGFBP-2). IGF-I has also been shown to decrease the urinary excretion of phosphate (Pi) in normal subjects. We hypothesized that IGF-I can raise tubule cell Pi absorption directly through an apical as well as a basolateral tubule receptor mechanism, specifically, through IGF-I (type I) receptors as compared to IGF-II (type II) or insulin receptors. Studies were performed in cultured proximal tubule cells that express high-affinity IGF-I receptors. Stimulation of cells selectively at the apical or basolateral membrane with IGF-I (10(-9) to 10(-7) mol/L) increases Pi absorption by up to 80%, but a significant counterdirectional Pi flux in the apical-to-basolateral direction does not occur. The effect of IGF-I on Pi transport appears to be specific inasmuch as the transport of alanine is not affected by the peptide. IGFBP-2 does not inhibit this effect of IGF-I, but the IGF-I-induced increase in Pi transport is inhibited by a neutralizing anti-IGF-I receptor monoclonal antibody. Exposure of the cells to IGF-II (10(-7) mol/L) but not to insulin selectively at the apical membrane tends to increase Pi transport, and this IGF-II effect is also blocked by the anti-IGF-I receptor antibody.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorption↗
PubMed1994

Complete nucleotide sequence of Saccharomyces cerevisiae chromosome VIII.

The complete nucleotide sequence of Saccharomyces cerevisiae chromosome VIII reveals that it contains 269 predicted or known genes (300 base pairs or larger). Fifty-nine of these genes (22 percent) were previously identified. Of the 210 novel genes, 65 are predicted to encode proteins that are similar to other proteins of known or predicted function. Sixteen genes appear to be relatively recently duplicated. On average, there is one gene approximately every 2 kilobases. Although the coding density and base composition across the chromosome are not uniform, no regular pattern of variation is apparent.

Base Composition↗
PubMed1994

Monocyte rolling, arrest and spreading on IL-4-activated vascular endothelium under flow is mediated via sequential action of L-selectin, beta 1-integrins, and beta 2-integrins.

Leukocyte interactions with vascular endothelium at sites of inflammation can be dynamically regulated by activation-dependent adhesion molecules. Current models, primarily based on studies with polymorphonuclear leukocytes, suggest the involvement of multiple members of the selectin, integrin, and immunoglobulin gene families, sequentially, in the process of initial attachment (rolling), stable adhesion (arrest), spreading and ultimate diapedesis. In the current study, IL-4-activated human umbilical vein endothelium, which selectively expresses VCAM-1 and an L-selectin ligand but not E-selectin, and appropriate function blocking monoclonal antibodies, were used to study monocyte-endothelial interactions in an in vitro model that mimics microcirculatory flow conditions. In this system, L-selectin mediates monocyte rolling and also facilitates alpha 4 beta 1-integrin-dependent arrest, whereas beta 2-integrins are required for spreading of firmly attached monocytes on the endothelial cell surface but not their arrest. These findings provide the first in vitro evidence for human monocyte rolling on cytokine-activated endothelium, and suggest a sequential requirement for both beta 1- and beta 2-integrin-dependent adhesive mechanisms in monocyte-endothelial interactions.

Antigens, CD↗
PubMed1994

Characterization of fibrinogen-binding properties of Actinomyces pyogenes.

This study was designed to further characterize the fibrinogen-binding properties of Actinomyces pyogenes. The fibrinogen-binding capacities of a selected A. pyogenes culture could be significantly enhanced by heat pretreatment (60 degrees C, 1 h) of the bacteria. The fibrinogen-binding site seemed to be a protein which was specific for fibrinogen. In phagocytosis studies, binding of fibrinogen to A. pyogenes significantly increased the phagocytic capacity of bovine polymorphonuclear leucocytes.

Actinomyces↗
PubMed1994

Myometrial expression of mRNA encoding epidermal growth factor receptor (EGFR) throughout the menstrual cycle.

PROBLEM: To investigate the quantitative changes in expression of EGFR mRNA in the myometrium throughout the menstrual cycle. METHOD: Myometrium was collected at hysterectomy from 27 women with a history of regular cycles. Total RNA (20 micrograms) was isolated and analyzed by Northern blot using a human EGF-R specific 32P-labeled cDNA probe. The hybridization signals were quantified by densitometry, standardized, and reported in densitometry signal units (DSU). Endometrial specimens from the same uteri were simultaneously evaluated for histologic dating of menstrual cycle day. EGFR gene expression in endometrium was previously reported. Statistical significance of the differences in myometrial gene expression between menstrual phases was evaluated by student's t test. RESULTS: EGFR mRNA was expressed in all myometrial tissues tested. Levels were higher in the late proliferative phase than in all other phases (P < .05). Women over 40 years old had lower proliferative phase expression than younger women. CONCLUSION: This data suggests that myometrial EGFR mRNA expression varies in association with the histologic phases of the normal menstrual cycle, and may be affected by aging, even when cycles occur at regular intervals.

Adult↗
PubMed1994

[Hepatitis C virus infection among the plasmapheresis donors].

We have made a retrospective study on 621 HBsAg negative plasma donors, 354 HBsAg negative non-blood donors, 124 HBsAg positive plasma donors and 124 HBsAg positive non-blood donors. Results showed that the respective positive rates of anti-HCV were 84.2%, 0.85%, 41.9% and 1.6%, and that the respective prevalence rates of viral hepatitis were 34.9%, 1.98%, 18.5% and 4.8%, respectively. These figures suggest that HCV infection and the epidemic of hepatitis C mostly occur among the plasma donors.

Adult↗
PubMed1994

[Studies on HDV and HCV infection in plasma donors with positive HBsAg].

Studies on HDV and HCV infection were carried out in 127 plasma donors and 152 non-donors carrying HBsAg. Results showed 7.9% (10/127) of the plasma donors and 1.3% (2/152) of the non-donors carrying HBsAg infected with HDAg, 41.7% (53/127) and 2.6% (4/152) with anti-HCV positive, and with prevalence rates of hepatitis of 18.1% (23/127) and 4.6% (7/152), respectively. The studies also indicated higher rates of HDV and HCV infection and prevalence of hepatitis may be caused by cross-infection during the course of plasmapheresis.

Adult↗
PubMed1994

Preparation, characterization and application of monoclonal antibodies against PAI-1.

Six hybridoma cell lines (AP1-AP6) secreting monoclonal antibodies (McAb) against PAI-1 were obtained by fusing the murine myeloma cell line SP2/0 with the spleen cells from Balb/c mouse immunized with recombinant PAI-1 expressed in E. coli. These antibodies were purified by SPA affinity chromatography. All McAbs recognized rPAI-1 and PAI-1 from the human hepatoma cell line HepG2. The titers of ascites were more than 10(6). The antibody-antigen affinity constants (Kaff) for anti-PAI-1 McAb measured by EIA were between 3.45 x 10(7)-1.05 x 10(10) M. AP2 and AP3 McAbs were effective in quenching the activity of PAI-1. Partial quenching of PAI-1 activity was achieved with AP4, AP5 and AP6 McAbs respectively. AP1 McAb had no effect upon PAI-1 activity. Three of the six McAbs (AP1, AP4 and AP5) bound to the PAI-1/t-PA complex, while the others did not. The PAI-1 was purified 51 folds to homogeneity from serum free medium of HepG2 with the recovery rate of 92% by one-step procedure using Sepharose 4B conjugated with anti-PAI-1 McAb (AP1, AP3 and AP4). A sandwich ELISA for the measurement of PAI-1 antigen in human plasma was developed, based on anti-PAI-1 McAb against non-overlapping epitopes. The mean value of plasma PAI-1 for the healthy donors was 24.7 +/- 7.75 ng/ml measured by ELISA.

Animals↗
PubMed1994

[Analysis of national maternal death surveillance: 1989-1991].

An analysis of maternal mortality in 247 cities, districts and countries of 30 provinces, municipalities and autonomous regionscovering a population of 100,000,000 in China in 1989-1991 was reported. The total number of live births was 4,201,457 in the pilot area, and the number of maternal deaths was 3,274 giving an average maternal mortality rate (MMR) of 80.0/100,000. After correction, the average MMR was 87.8/100,000. The MMR per annum was in decreasing trends and in different regions were different from one another. The first 6 leading causes of maternal deaths in 3,274 cases, in decreasing order of importance, were: obstetric hemorrhage, pregnancy induced hypertension, cardiac diseases, puerperal infection, amniotic fluid embolism, and hepatic diseases. The result of audit on maternal deaths was as follow: 89.0% of the maternal deaths were avoidable, and 11.0% were unavoidable. Three aspects of the maternal deaths in China were formulated form this study.

Adult↗