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Biomedical subjects

H Zhong

Publications and source records attributed to H Zhong.

At least 145 records · Page 8Linked to original sources
PubMed1995

[Attachment of bacillus Calmette-Guerin to bladder cancer cells and the expression of interleukin-6 biological activity].

In order to elucidate the mechanisms of antitumor efforts of bacillus Calmette-Guerin (BCG), the effects of attachment of BCG to bladder carcinoma cell line EJ and the role of fibronectin in the in vitro experiment were studied. At the same time, the IL-6 biological activity in the medium of EJ cells was determined and the IL-6 biological activity in presence of BCG compared. The results indicated that BCG attached strongly to EJ cells, and the maximal attachment to the cells with BCG occurred 48 hours after culture. Fibronectin could significantly increase the attachment and not acclerate the proliferation of EJ cells. In the presence of fibronectin-conditioned medium, the maximal percentage of the tumor cells with attached BCG was 74.22%. Under this condition of experiment, there was IL-6 biological activity in the medium of EJ cells. The treatment of EJ cells with BCG did not regulate the expression of IL-6.

Cell Adhesion↗
PubMed1995

[Pharmacological studies of Polygonum capitatum Buch-Ham. ex D. Don].

The pharmacological effect of aqueous extract of Polygonum capitatum has been studied. The experimental results show that Polygonum capitatum markedly decreases WBC and RBC in urine of pyelonephritis mode in rats, the death rate of Escherichia coli infected mice, and the temperature of feverish rabbits. It has also been found that after oral administration of Polygonum capitatum the animal urine markedly inhibits the growth of Escherichia coli, but diuretic action of the herb has not been observed.

Animals↗
PubMed1995

Coexisting beta-1 and beta-2-adrenergic receptors with differential receptor reserves in rat C6 glioma cells.

The coupling efficiencies of beta-1 and beta-2-adrenergic receptors (ARs) in rat C6 glioma cells and the effect of changes in subtype density and ratio caused by dexamethasone (DEX) treatment were studied. Radioligand binding studies in membranes suggested that beta-2-ARs showed slightly larger GTP-induced decreases in agonist affinity than beta-1-ARs, which suggests more ternary complex formation with Gs. Treatment with DEX increased the proportion of beta-2-ARs from 20% to 60% without affecting GTP-induced decreases in agonist affinity. Coupling efficiency was determined directly by progressive inactivation of beta-ARs with the irreversible alkylating agent pindobind, which caused similar reductions in beta-1 and beta-2-AR binding sites. Studies on cyclic AMP accumulation showed that DEX-induced decreases in beta-1/beta-2 ratio reduced the receptor reserve for the beta-1-selective agonist norepinephrine but increased the maximal response to the beta-2-selective agonist zinterol without creating a receptor reserve. DEX treatment did not alter occupancy-response curves or maximal responses to the nonselective agonists isoproterenol and epinephrine. It was concluded that changing beta-2-AR density alters the maximal response to beta-2-AR activation; changing beta-1-AR density alters the apparent beta-1-AR reserve. Both subtypes contribute to the responses to nonselective agonists in a nonadditive manner. Beta-1- and beta-2-ARs appear to couple with different efficiencies (beta-1 > beta-2) to cyclic AMP accumulation in C6 glioma cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

[Systemic manifestations of adult polycystic kidney disease: an analysis of 205 cases].

Adult polycystic kidney disease (APKD) is a common genetic disease and one of the important reasons of end stage renal failure. Although renal multiple cysts are clearly an important manifestation of APKD; other systemic manifestations are both common and clinically important. The authors reviewed 205 cases from 180 APKD families (107 male 98 female). Their age ranged from 10 to 71 years. Renal cyst is one of the many renal manifestations. Hypertension, hematuria and flank pain are its major complications. Hepatic cysts, pancreatic cysts, cardiac valvular lesions, intracranial aneurysms and splenic cysts are included in the array of systemic manifestations.

Adolescent↗
PubMed1995

Selective desensitization of beta 1- and beta 2-andrenergic receptors in C6 glioma cells. Effects on catecholamine responsiveness.

We studied the effects of changing beta 1- and beta 2-adrenergic receptor (AR) subtype ratios and densities on cyclic AMP (cAMP) responses to norepinephrine (NE) and epinephrine (EPI) in rat C6 glioma cells. Dexamethasone (DEX) increased beta 2- and decreased beta 1-AR expression without changing total beta-AR density, whereas pretreatment with selective agonists specifically downregulated each subtype. Combinations of these treatments produced cells with six different beta 2/beta 1 ratios that ranged from 0 (100% beta 1) to 2.85. We compared the effects of NE and EPI on cAMP accumulation in each condition and observed a predominantly beta 1 pharmacology (NE > EPI) under most conditions. However, as the beta 2-AR density exceeded the number of beta 1-ARs we observed a progressive shift toward a more beta 2-like pharmacology (EPI > NE), without the appearance of biphasic concentration-response curves. The ratio of beta 2/beta 1 density correlated significantly (p < 0.006) with the ratio of the potencies of NE and EPI in increasing cAMP formation. We conclude that in native C6 cells beta 1-ARs appear to couple more efficiently to cAMP accumulation than do beta 2-ARs, but both subtypes contribute to catecholamine responses in a nonadditive manner when the proportion of beta 2-ARs is increased.

Adrenergic beta-Agonists↗
PubMed1994

[A new species of Thermoplasma].

An extremely thermoacidophilic strain, ES-23, was isolated from a self-heating coal spoil pile, Sichuan, China. The new isolate grows between 50 and 75 degrees C with optimum 70 degrees C and pH 1.0-5.0 with optimum 2.0. Strain ES-23 is aerobic and facultative autotrophic depending both heterotrophically on organic compounds and autotrophically on elemental sulfur as energy source and CO2 as carbon source. G-, spherical or oval with 0.9-1.5 microns in diameter. The autotrophic growth showed peri pilus-like structure. Cells Lack a rigid cell wall and surrounded only by a single triple layed membrane containing ether lipids. GC content of DNA is 38 mol%(Tm). It has been determined as a new species of Thermoplasma genus and named Thermoplasma thiooxidans sp. nov.

Terminology as Topic↗
PubMed1994

Effects of liuwei dihuang wan [symbol: see text:bd and some other TCM drugs on bone biomechanics and serum 25 (OH)D3 content in rats.

After a relatively long-term injection of hydrocortisone into rats, the strength of bone (anti-stress capacity) reduced evidently, while the rigidity (anti-deformity capacity) increased markedly (ie, bone fragility elevated). At the same time, the content of serum 25(OH)D3 decreased remarkably. After oral administration of Liuwei Dihuang Wan ([see symbol: see text]), anti-stress capability of bone increased evidently and its anti-deformity capability returned to normal; however, there was no elevation of serum 25(OH)D3 content. The effect of Longmu Zhuanggu Chongji ([see symbol: see text]) or Jisheng Shenqi Wan (see symbol: see text]) was lower than that of Liuwei Dihuang Wan. The experiments suggests that Liuwei Dihuang Wan is beneficial to preventing and curing osteoporosis, but no correlation between its mechanism and the metabolism of 25(OH)D3 was demonstrated.

Animals↗
PubMed1993

Close reciprocal regulation of beta 1- and beta 2-adrenergic receptors by dexamethasone in C6 glioma cells: effects on catecholamine responsiveness.

We studied the regulation of beta-adrenergic receptor (AR) subtypes co-existing in rat C6 glioma cells to clarify the importance of subtype ratio in responses to catecholamines. Radioligand binding studies with [125I]-cyanopindolol showed that beta 1- and beta 2-ARs co-existed in this cell line in approximately an 80:20 ratio. Norepinephrine (NE) and epinephrine (EPI) were equally potent in increasing cAMP accumulation, consistent with a primarily beta 1-response, although both beta 1- and beta 2-components of the response could be isolated using selective agonists (NE and zinterol), and antagonists (CGP 20712A and ICI 118,551). Little or no evidence of beta 3-ARs could be found in this cell line. Treatment of cells with 500 nM dexamethasone (DEX) for 48 hr increased the proportion of beta 2-ARs (20 to 60%). However, a reciprocal decrease in beta 1-ARs resulted in no change in total beta-ARs. Studies on the time-(12 to 72 hr) and concentration- (5 nM to 5000 nM) dependence of DEX treatment showed that increases in beta 2-ARs were closely linked to decreases in beta 1-ARs with little or no change in total receptor density observed at any time or in any concentration studied. Treatment with DEX also increased beta 2- and decreased beta 1-mediated cAMP responses, but did not alter the response to the nonselective agonist, isoproterenol. Northern blot analysis showed a 2- to 3-fold increase in beta 2-AR mRNA, but no change in beta 1-AR mRNA, after exposure to 50 or 500 nM DEX for 48 hr. Surprisingly, after DEX treatment, NE and EPI were still equally potent in activating cAMP accumulation, although responses to the beta 2-selective agonist, zinterol, were increased. These studies show a close reciprocal regulation by DEX of the relative proportions of beta 1- and beta 2-AR subtypes in C6 cells. The functional significance of the changing subtype ratios does not appear to be related to catecholamine responsiveness.

Adrenergic beta-Agonists↗
PubMed1992

Selective expression of mitogen-inducible cyclooxygenase in macrophages stimulated with lipopolysaccharide.

Two forms of cyclooxygenase are known to be present in eukaryotic organisms: a cyclooxygenase (COX-1) first purified from ram seminal vesicles encoded by a 2.8-kilobase mRNA, and a newly discovered mitogen-inducible cyclooxygenase (COX-2) encoded by a 4-kilobase mRNA. Expression of these two forms of the enzyme in rat alveolar macrophages stimulated with lipopolysaccharide was investigated by 1) determining the activity of newly synthesized enzyme after inactivating the endogenous enzyme with aspirin; 2) comparing levels of newly synthesized enzyme proteins in cells treated with or without lipopolysaccharide; and 3) assessing the expression of the mRNAs encoding COX-1 and COX-2. Levels of enzyme proteins were assessed by Western blot analysis and immunoprecipitation of 35S-labeled enzyme using two different antibodies, one specific for COX-2 and the other recognizing both forms of the enzyme but preferentially recognizing COX-1. We report here that the enhanced cyclooxygenase activity induced by the bacterial lipopolysaccharide in rat alveolar macrophages is caused by selective expression of the COX-2. Expression of COX-2 in macrophages stimulated by lipopolysaccharide was completely inhibited by dexamethasone, whereas COX-1 was unaffected. In resting unstimulated macrophages, only COX-1 but not COX-2 was detected. Levels of mRNA for the COX-2 in macrophages were increased, but those of the COX-1 were not affected by lipopolysaccharide as assessed by reverse transcription coupled with polymerase chain reaction. These results indicate that increased synthesis of prostaglandins and thromboxanes in lipopolysaccharide-stimulated macrophages results from selective expression of COX-2.

Animals↗
PubMed1988

Incorporation of [C]Glucose into Cell Wall Polysaccharides of Cotton Roots: Effects of NaCl and CaCl(2).

Cotton (Gossypium hirsutum L. cv Acala SJ-2) seedlings were grown in nutrient solutions with four combinations of NaCl (0.1 and 150 millimolar) and CaCl(2) (1 and 10 millimolar) for 7 days, and then exposed to [(14)C]glucose for 5 hours. Uptake and incorporation of [(14)C]glucose into various cell wall fractions of the root tips were determined. At 1 millimolar Ca(2+), treatment with 150 millimolar NaCl slightly stimulated uptake but considerably inhibited glucose incorporation into noncellulosic and cellulosic polysaccharides. Supplemental Ca(2+) did not affect incorporation of glucose into the noncellulosic fraction (regardless of NaCl treatment) but completely alleviated the inhibitory effect of NaCl on glucose incorporation into cellulose. We suggest that high Na(+) concentrations reduce synthesis of cellulose in cotton roots via disturbance of plasma membrane integrity and that supplemental Ca(2+) counteracts this effect. The effects on cellulose biosynthesis are proposed to be related to Ca(2+) displacement from the plasma membrane.

Journal Article↗