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T Zheng

Publications and source records attributed to T Zheng.

At least 91 records · Page 5Linked to original sources
PubMed1999

[Karyotype analysis of Carpesium cernuum].

The paper reported the chromosome number, karyotype and chromosome volume of Carpesium cernuum. The normal diploid was 2n = 40, karyotype formula based on Levan's publication was k(2n) = 40 = 24 m + 12 sm + 2 st + 2T. According to the method of S. R. Kuo, the chromosome relative length was 2n = 40 = 8L + 6M2 + 16M1 + 10S, which belong to "2B" type according to the Stebbins' karyotype classification. The AS.K% was 62.35% from Arano's method. The total volume of chromosome groups was 13.76 microns 3.

Asteraceae↗
PubMed1998

[Effects of Trp64Arg mutation in the beta 3-adrenergic receptor gene on body fat, plasma glucose level, lipid profile, insulin secretion and action in Chinese].

OBJECTIVE: To ascertain the association of the Trp64Arg mutation in the beta 3-adrenergic receptor (ADRB3) gene with the total body fat and fat distribution, plasma glucose level, lipid profile, insulin secretion and action in Chinese. METHODS: Genotyping of the Trp64Arg mutation in the ADRB3 gene as well as measurment of clinical variables body mass index(BMI), percent of desirable weight(PDW), area of regional adipose tissue depots, fasting lipid profile, and also, plasma glucose, insulin, C-peptide, free fatty acids levels before and after glucose challenge and blood pressure were performed in 308 Chinese, of whom, 161 were nondiabetics and 147, type 2 diabetic subjects. RESULTS: (1) The frequency of Arg64 allele of ADRB3 gene in Chinese was similar to that in Japanese but slightly higher than that in Caucasians. (2) No association of any of the clinical varaibles with Trp64Arg mutation was observed in nondiabetics. (3) The Trp64Arg mutation in the ADRB3 gene was associated with BMI(P=0.019), PDW(P=0.001) and waist circumference (P=0.045) in type 2 diabetic subjects. In female diabetic subjects, more significant association with BMI(P=0.001), PDW(P=0.001), waist circumference(P=0.023), and also, association with abdominal and femoral subcutaneous fat area(P=0.032 and P=0.023) were observed. The frequencies of Arg64 allele were 21%, 14% and 4% in female diabetics with obesity, over-weight and normal-weight respectively (P=0.026). Logistic regression analysis showed that BMI was the only independent clinical variable related to the Trp64Arg mutation in the ADRB3 gene (P=0.0027). CONCLUSION: The Trp64Arg mutation in ADRB3 gene contributes to the variation of total body fat in Chinese type 2 diabetic subjects.

Adipose Tissue↗
PubMed1998

C2-ceramide attenuates prostaglandin F2alpha-induced vasoconstriction and elevation of [Ca2+]i in canine cerebral vascular smooth muscle.

Sphingolipids have emerged as important components of signal transduction pathways involved in a variety of cellular processes. In the present study, we examined the effects of C2-ceramide, a cell-permeable sphingolipid, on contraction of canine cerebral vascular smooth muscle and intracellular free Ca2+ ([Ca2+]i). C2-ceramide (10(-8)-10(-4) M) alone did not elicit any significant changes in either basal tension or resting levels of [Ca2+]i in canine cerebrovascular muscle. However, C2-ceramide (10(-7)-10(-4) M) attenuated prostaglandin F2alpha (PGF2alpha)-induced contractions in isolated canine cerebrovascular smooth muscle rings. C2-ceramide (10(-5) M) inhibited the secondary phasic rise of [Ca2+]i evoked by PGF2alpha in cultured canine cerebral vascular smooth muscle cells, resulting in decreases in the elevation in [Ca2+]i. NO inhibitors (L-NNA, L-NMMA), an inhibitor of prostanoid synthesis (indomethacin), an inhibitor of opiate actions and several inhibitors of the pharmacologic actions of various vasoactive amines all failed to interfere with the vasorelaxant response of C2-ceramide. Our results suggest that the sphingomyelin signaling pathway may play an important regulatory role in cerebral arterial wall tone.

Animals↗
PubMed1998

Evidence for multiclonality in multicentric Kaposi's sarcoma.

Kaposi's sarcoma (KS) develops in a variety of clinical states and is the most common tumor seen in patients with HIV-1 infection. KS develops as a multifocal mucocutaneous disease with subsequent spread to visceral organs, and it has been argued to be a benign proliferation caused by its multifocality at initial presentation, lack of aneuploidy, and spontaneous regression upon withdrawal of immunosuppressive agents in iatrogenically induced disease. We wished to determine whether KS lesions are clonal, indicative of a true neoplasm. Also, we tested whether multifocal KS lesions are clonally related, derived from a common progenitor cell or of independent cellular origin. We studied the X-chromosome inactivation pattern of the human androgen receptor gene in tumor biopsies of women with KS. This procedure tests for the clonality of a tissue specimen, a hallmark of neoplasia. Each specimen was microdissected to minimize normal cell contamination. Of 12 evaluable cases, 10 were HIV-seropositive and 2 were HIV-seronegative. Twenty-four biopsies from the 12 patients were examined. Five cases were consistent with individual KS lesions being clonal. In two cases, multiple KS specimens derived from the individual patients had different androgen receptor alleles inactivated, proving unequivocally that these KS lesions arose independently from distinct transformed cells. In seven cases, only a polyclonal pattern of inactivation was observed, whereas two others had tumor areas of both clonal and polyclonal inactivation patterns. These findings suggest that KS can be a clonal neoplasm, and in some of the cases multiple KS lesions in a given patient can arise from independent cellular origins and acquire clonal characteristics. The polyclonal inactivation pattern observed in other KS lesions may represent a premalignant stage or false negative results.

Adult↗
PubMed1998

Connectivity and convergence of single corticostriatal axons.

The distribution of synapses formed by corticostriatal neurons was measured to determine the average connectivity and degree of convergence of these neurons and to search for spatial inhomogeneities. Two kinds of axonal fields, focal and extended, and two striatal tissue compartments, the patch (striosome) and matrix, were analyzed separately. Electron microscopic examination revealed that both kinds of corticostriatal axons made synapses at varicosities that could be identified in the light microscope, and each varicosity made a single synapse. Thus, the distribution of varicosities was a good estimate of the spatial distribution of synapses. The distance between axonal varicosities was measured to determine the density of synaptic connections formed by one axon within the volume occupied by a striatal neuron. Intersynaptic distances were distributed exponentially, except that synapses were rarely located <4 microm apart. The mean distance between synapses was approximately 10 microm, so axons made a maximum of 40 synapses within the dendritic volume of a spiny neuron. There are approximately 2840 spiny neurons located within the volume of the dendrites of one spiny cell (Oorschot, 1996), so each axon must contact </=1.4% of all cells in its axonal arborization. Within the same volume there are approximately 30.5 million asymmetric synapses (Ingham et al., 1996), approximately half of which are cortical in origin. Thus, approximately 380,000 cortical axons innervate the volume of the dendritic tree of one spiny cell. Striatal neurons with totally overlapping dendritic volumes have few presynaptic cortical axons in common, and cortical cells with overlapping axons have few striatal target neurons in common. These results explain the absence of redundancy in the responses of neurons located near each other in the striatum.

Animals↗
PubMed1998

Alpha-tocopherol prevents ethanol-induced elevation of [Ca2+]i in cultured canine cerebral vascular smooth muscle cells.

Exposure of cultured canine cerebral vascular smooth muscle cells to ethanol (10-400 mM) for 1-5 days results in concentration-dependent elevation in resting intracellular free calcium ([Ca2+]i) levels. Preincubation of these cultured vascular cells with alpha-tocopherol (20 microM), alone, did not produce any apparent changes from control resting levels of [Ca2+]i. However, after concomitant addition of alpha-tocopherol (20 microM) and ethanol (10-400 mM), the rises of [Ca2+]i induced by ethanol were attenuated markedly. These results suggest that alcohol-induced lipid peroxidation of cerebral vascular muscle cell membranes triggers membrane entry of extracellular Ca2+, which could play an important role in ethanol-induced cerebrovasospasm, brain ischemia and stroke. Moreover, these new results support the concept recently advanced to suggest that alpha-tocopherol-induced amelioration of membrane lipid alterations of cerebral vascular cells can prevent ethanol-induced excessive accumulation of [Ca2+]i.

Animals↗
PubMed1998

Mechanisms of hydrogen peroxide-induced contraction of rat aorta.

It has been suggested that reactive oxygen species may be involved in the regulation of vascular tone. However, the underlying mechanisms remain to be elucidated. The present studies were designed to investigate the contractile effects of hydrogen peroxide (H2O2), one of the reactive oxygen species, on isolated ring segments of rat aorta with and without endothelium. H2O2 induced an endothelium-independent contraction in isolated rat aorta ring segments in a concentration-dependent manner at concentrations from 5 x 10(-6) to 5 x 10(-3) M. H2O2-induced contractions of denuded rat aorta rings were stronger than those on intact rat aorta segments. The contractile effects of H2O2 were inhibited completely by 1200 u/ml catalase. The presence of 1.0 microM Fe2+ or 10 microM proadifen, a cytochrome P450 monooxygenase inhibitor, potentiated the contractile effect of H2O2 on isolated rat aorta segments. 1 mM deferoxamine (a Fe2+ chelator) or 100 microM dimethyl sulfoxide (a hydroxyl radical scavenger) significantly attenuated the vessel contractions induced by hydrogen peroxide plus Fe2+ or hydrogen peroxide itself. Removal of extracellular Ca2+ ([Ca2+]0), addition of 5 microM verapamil, administration of a protein kinase C inhibitor (staurosporine), treatment with an inhibitor of protein tyrosine phosphorylation (genistein) or employment of 5.0 microM indomethacin resulted in a significant attenuation of the contractile responses of the vessels to H2O2. Pharmacological antagonists (e.g. a muscarinic acetylcholine receptor antagonist (atropine), an antagonist of histamine H1 receptors (diphenhydramine), an antagonist of histamine H2 receptors (cimetidine), an alpha-adrenoceptor antagonist (phentolamine), a beta-adrenoceptor antagonist (propranolol) and an antagonist of serotonin receptor (methysergide)) did not inhibit or attenuate the contractions induced by H2O2. Exposure of primary aortic smooth muscle cells to H2O2 (5 x 10(-6) to 5 x 10(-3) M) produced significant rises of intracellular Ca2+ ([Ca2+]i) within 20 s. Employment of 1.0 microM Fe2+ markedly enhanced the increment in [Ca2+]i in the smooth muscle cells. 10 microM proadifen treatment failed to alter the hydrogen peroxide-induced increment in [Ca2+]i of the smooth muscle cells. However, the presence of 5 microM indomethacin significantly attenuated the rise in [Ca2+]i in smooth muscle cells. The present results suggest that H2O2 can induce contractions of rat aorta segments, at pathophysiological concentrations, which are Ca2+-dependent. Hydroxyl radicals (.OH), cyclooxygenase products, protein kinase C and products of protein tyrosine phosphorylation appear to play some role in hydrogen peroxide-induced contractions. Metabolites catalyzed by cytochrome P450-dependent enzymes (upon treatment with hydrogen peroxide) appear to exert a vasodilator effect on rat aorta segments. Lastly, some unidentified mediators, produced by a cytochrome P450 inhibitor (proadifen), during hydrogen peroxide treatment, appear to play some role in contraction of vascular smooth muscle of rat aorta segments in vitro.

Animals↗
PubMed1998

[The relationship between angiotensin II type 1 receptor gene and coronary heart disease, hypertension and diabetes mellitus in Chinese].

OBJECTIVE: To ascertain whether the angiotensin II type 1 receptor (AGTR1) gene is associated with coronary heart disease (CHD), hypertension (HTN) and non-insulin-dependent diabetes mellitus (NIDDM) in Chinese and to observe the interaction of AGTR1 gene and angiotensin I converting enzyme(ACE) gene to the development of the associated disease in Chinese. METHODS: 270 cases of Chinese with CHD, HTN or NIDDM in single or in different combinations were genotyped for the A1166C variation at the 3'-untranslated region of AGTR1 gene by using PCR/Dde I restriction endonuclease digestion. And also, the insertion/deletion polymorphism at the intron 16 of ACE gene was typed by PCR. RESULTS: (1) AGTR1 gene was associated with CHD (logistic regression analysis, P=0.02), but not with HTN and NIDDM; (2) The attributable risk of AGTR1 gene for CHD was 12.5% and the odds ratio was 4.55. Both AGTR1 gene and ACE gene were independent variation factors for CHD (P=0.032 and P=0.002 respectively); (3) The contribution of AGTR1 gene to the development of CHD was independent of total body adiposity, blood lipid profile and blood pressure; (4) The analysis of individual combined genotypes of AGTR1 gene and ACE gene showed significant difference in frequency distribution between patients with CHD and controls. CONCLUSION: AGTR1 gene contributes to the development of CHD and is an independent risk factor for CHD in Chinese.

Adult↗
PubMed1998

Staurosporine and H7 attenuate ethanol-induced elevation in [Ca2+]i in cultured canine cerebral vascular smooth muscle cells.

Chronic exposure of cultured canine cerebral vascular smooth muscle cells to ethanol (10-400 mM) for 1-5 days resulted in significant concentration-dependent elevation in resting intracellular free calcium ([Ca2+]i) levels. Preincubation of these cultured vascular cells with inhibitors of protein kinase C (PKC), staurosporine and H7, induced no apparent changes from the control resting levels of [Ca2+]i. However, the increases of [Ca2+]i due to ethanol treatment were attenuated markedly by staurosporine and H7. Our data suggest that activation of PKC plays an important role in ethanol's action in producing a sustained rise in [Ca2+]i in cerebral vascular smooth muscle cells. Activation of PKC could thus play a crucial role in the pathogenesis of alcohol-induced cerebral ischemia and stroke.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1998

Effect of supplemental beta-carotene on plasma concentrations of carotenoids, retinol, and alpha-tocopherol in humans.

High doses of beta-carotene, a lipid-soluble nutrient, may affect the plasma concentrations of other lipid-soluble nutrients. The purpose of this study was to assess the effects of long-term daily supplementation with beta-carotene (50 mg/d) on circulating concentrations of other carotenoids, retinol, and alpha-tocopherol over time. Data were available from 259 men and women participating in the Carotene Prevention Trial, a 2-center chemoprevention trial designed to determine whether supplemental beta-carotene can prevent second malignant tumors in patients cured of an early stage cancer of the oral cavity, pharynx, or larynx. Up to 2 blood samples were obtained before the intervention (before and after a 1-mo placebo run-in), with postrandomization samples obtained at 3, 12, 24, 36, 48, and 60 mo. Supplementation with beta-carotene produced a persistent 9- to 10-fold increase in median plasma beta-carotene concentrations (225 nmol/L at baseline to 2255 nmol/L at 3 mo) and a persistent 2-fold increase in median plasma alpha-carotene concentrations (45 nmol/L at baseline to 95 nmol/L at 3 mo). Concentrations of retinol, alpha-tocopherol, lycopene, and lutein/zeaxanthin were not affected by supplemental beta-carotene. Up to 5 y of daily supplementation with beta-carotene increased circulating concentrations of alpha- and beta-carotene, but did not alter concentrations of lycopene, lutein/zeaxanthin, retinol, or alpha-tocopherol.

Adult↗
PubMed1998

Sunlamp use and the risk of cutaneous malignant melanoma: a population-based case-control study in Connecticut, USA.

BACKGROUND: The relationship between cutaneous malignant melanoma and sunlamp use is examined in a Caucasian population in Connecticut, United States. METHODS: Cases were diagnosed between 15 January 1987 and 15 May 1987 with a first primary cutaneous melanoma. Controls were obtained from the general population, frequency matched to cases by sex and age, through random digit dialling of Connecticut telephone numbers. RESULTS: Of all study subjects, 141 (23%) cases and 95 (19%) controls reported ever having used sunlamps. The crude odds ratio (OR) for developing malignant melanoma after ever having used sunlamps was 1.30 (95% confidence interval [CI]: 0.97-1.74). This was reduced to 1.13 (95% CI: 0.82-1.54) after further adjusting for cutaneous phenotype and recreational sun exposure. Those who used more than one type of sunlamp had a threefold higher risk for melanoma compared to never users. Subgroup analyses showed that sunlamp use was associated with a greater increase in risk for melanoma among those who used sunlamps at home and those who were first exposed to sunlamps prior to 1971. The first use of sunlamps before the age of 25 showed somewhat higher risk for melanoma compared to first use later in life. CONCLUSION: The current study provides limited evidence that use of sunlamps increases the risk of melanoma. For future studies, it is crucial that type of sunlamp, year of first use and amount of exposure are all taken into account. The association between melanoma and tanning with both UV-A and UV-B lamps and tanning under sunlamps early in life merits further investigation.

Case-Control Studies↗
PubMed1998

Emerging treatments for epidemic (AIDS-related) Kaposi's sarcoma.

Kaposi's sarcoma (KS) is an opportunistic tumor that develops with increased frequency (100,000-fold) after HIV infection. KS causes significant morbidity from mucocutaneous involvement and mortality from complications of visceral sites of disease such as the lungs, gastrointestinal tract, and the liver. Progressive unraveling of the KS pathogenesis has lead to the development of novel therapeutic approaches. Newest therapies are first evaluated in patients with limited tumor burden. These include: 1) inhibitors of angiogenesis such as vascular endothelial growth factor signaling inhibitor (SU 5416), and several other inhibitors of angiogenesis such as the dipeptide IM 862, TNP-470, Col-3, and thalidomide; 2) topical and systemic retinoids; 3) antiviral agents specific for Kaposi's sarcoma herpesvirus and human herpesvirus-8, or HIV; and 4) pregnancy-related factors. Patients with advanced disease such as widespread mucocutaneous disease, lymphedema, and visceral disease are treated most effectively with cytotoxic agents. The most active agents include liposomal anthracyclines, paclitaxel, vinca alkaloids, and bleomycin. The combination of liposomal anthracyclines and paclitaxel, with and without the most promising biologicals, should now be studied to further reduce the toxicity, and enhance the antitumor effects. Furthermore, identification of risk factors for KS should serve to explore prophylactic therapies.

AIDS-Related Opportunistic Infections↗
PubMed1998

[The impact of the missense mutation-ser20gly in islet amyloid polypeptide gene on NIDDM in Chinese].

OBJECTIVES: To ascertain the presence of the Ser 20Gly mutation of islet amyloid polypeptide (IAPP) gene and its impact on NIDDM in Chinese. METHODS: In 896 Chinese, 825 were unrelated subjects (NIDDM in 609 and non-diabetics, 216) and 71 were family members of the pedigrees with IAPP gene-Ser 20Gly carrier probands detected from population screening. The mutation was examined by PCR-RFLP MspI digestion in population screening and the results was randomly checked by direct DNA sequencing. Data were analyzed through association as well as linkage approaches. RESULTS: The Ser20Gly mutation of the IAPP gene was observed in Chinese. It was more prevalent in NIDDM (17 cases, 2.8%) than in non-diabetics (1 cases, 0.5%) (Fisher two-tailed exact P = 0.05). The mutation carrier detected by PCR-RFLP was confirmed to be the A to G point mutation in nucleotide 582 of IAPP gene cDNA encoding the amino acid codon 20. All the mutation carriers detected in population screening were heterozygotes. Analysis of the family members of the 12 NIDDM pedigrees with the IAPP gene Ser20Gly mutation showed that in two families, the mutation was not cosegregated with the affection status. The older was the age of Ser20Gly mutant carrier, the more prevalent was the diabetes in families (P = 0.0001). The highest total lod score of this 12 pedigree was 0.021(theta = 0) in parametric linkage analysis with the model of autosomal dominance with incomplete penetrance. CONCLUSION: The Ser20Gly mutation of IAPP gene was present in Chinese. This mutation does not cause monogenic inheritance diabetes, but may be a pathogenetic factor for the development of NIDDM, the complex genetic disease.

Adult↗
PubMed1998

[Detection of Mycobacterium tuberculosis DNA in peripheral blood mononuclear cells from patients with pulmonary tuberculosis by polymerase chain reaction technique].

OBJECTIVE: To evaluate the clinical value of detection of Mycobacterium tuberculosis DNA (MTB-DNA) in peripheral blood mononuclear cells (PBMC) for diagnosis of pulmonary tuberculosis. METHOD: Polymerase chain reaction (PCR) technique was used to amplify gene of 240 bp DNA fragment prepared by Triton X-100 method, and some factors affecting PCR result were also analysed. RESULT: In blood samples of 89 patients with pulmonary tuberculosis and in sputum samples of 84 patients with pulmonary tuberculosis, the positive rates of PCR were 73% and 57% respectively, and the total positive rate of combinative detection of blood and sputum samples was 87% in 84 pulmonary tuberculosis patients. In 30 non-tuberculosis patients, 3 showed MTB-DNA positive. CONCLUSION: PCR technique prepared by Triton X-100 method is rapid, simple, specific, and sensitive for detection of MTB-DNA in PBMC, and its sensitivity and accuracy could be increased in combination with sputum MTB examination. Detection of MTB-DNA in PMBC is of value in diagnosis of pulmonary tuberculosis.

DNA, Bacterial↗
PubMed1998

[The diagnosis and treatment of primary carcinoma of the duodenum].

OBJECTIVE: To improve the diagnosis and treatment of primary duodenal carcinoma. METHOD: The records of 18 patients with primary carcinoma of the duodenum were reviewed. RESULT: 7 cases underwent pancreatoduodenectomy: segmental duodenectomy (1), intraoperative death (1), survived 3 years (2), and survived 5 years after operation (3). 7 cases underwent gastroenterostomy or cholangioenterostomy; they died in 11 months after operation. Three cases who received biopsy only died in six months after operation. CONCLUSION: The understanding of duodenal carcinoma is the key factor for early diagnosis. The appropriate examinations are necessary for suspected patients. Once the diagnosis is confirmed, the result of surgical treatment is improved.

Adult↗
PubMed1998

[Karyotype analysis on Iris lactea ssp. chinensis].

In this paper, the chromosome number, karyotype and chromosome volume of Iris lactea ssp. chinensis were reported. The normal diploid was 2n = 32. Karyotype formula was based on Levan's publication in 1964, k (2n) = 32 = 22 m + 8 sm + 2T. According to the method of Kuo SR, the species chromosome based on the relative length was 2n = 32 = 6L + 4 M2 + 18 M1 + 4 S which belong to "2A" type according to the Stebbins' karyotype classification. The AS.K% was 62.5% from Arano's method. The total volume of chromosome groups was 34.95 micron 3.

Base Sequence↗
PubMed1998

[Application of charge transfer reaction in the determination of aminosalicylate sodium].

A spectrophotometric method for the determination of aminosalicylate sodium has been developed based on the charge transfer reaction. The Beer's law is obeyed in the range of 40-160 microg/mL of aminosalicylate sodium. The apparent molar absorptivity of the complex at 660nm is 1.17 X 10(3)L x mol(-1). The average standard deviation of ten determination is 0.67%. The composition of aminosalicylate sodium 2, 6-Dichloroquinone chlorimide complex is 1:1. The proposed method has been applied to the determination of aminosalicylate sodium tablets with satisfactory results.

Absorption↗