Biomedical subjects

H Tian

Publications and source records attributed to H Tian.

At least 109 records · Page 6Linked to original sources

PubMed1997

[Comparison of the Chinese LJ strain structural gene with HM175, MBB, LA strains and the expression of hepatitis A virus antigen by LJ/HM175 recombinant vaccinia virus].

The nucleotide and amino acid sequences of a Chinese hepatitis A virus Long-Jia (LJ) strain were compared with that of HM175, MBB and LA strains in structural genes (nt 630-3049). The most extensive nucleotide homology was identified between LJ and MBB strains. The identity rates of nucleotide were 95.4%, 96.7% and 91.4%, respectively. Variation rates of amino acid were 0.91%, 0.91% and 2.98%, respectively. A total of 23 amino acid differences located in whole capsid region between LJ and LA strain, especially in VP1. Only 7 amino acid differences located in VP2 and VP3 between LJ and HM175/MBB strain. Restriction enzyme sites increased 10, 13 and 30 sites in 56 restriction enzymes tested, and decreases 15, 1 and 27 sites, respectively. BstE II (nt 2810) and Pvu I (nt 2013) were the peculiar sites of LJ strain. Hind III, Pst I and Sac I sites were identical among the four strains. After structural gene (nt 745-2993) of HM175 strain was replaced by LJ strain, the complete hepatitis A virus cDNA open reading frame was inserted into pJSA1175 (vaccinia virus expression vector) downstream of promoter 7.5 k. Hepatitis A virus antigen expressed was 1:16 in titer by sandwich ELISA. Band-patterns of anti-VP0, anti-VP1 and anti-VP1, 2, 3, were as same as that of HM175 strain and natural hepatitis A virus antigen by Western blot analysis.

Hepatitis A Antigens↗

PubMed1997

[Oral low-dose magnesium gluconate preventing pregnancy induced hypertension].

OBJECTIVE: To study the effects of oral low-dose magnesium gluconate in prevention of pregnancy induced hypertension (PIH) and its mechanism. METHODS: A prospective randomized double-blind study was carried out in 51 pregnant women as treatment group (including 22 cases as treatment group 1 and 29 cases as treatment group 2) and 51 pregnant women as controls (including 28 cases as controls group 1 and 23 cases as control group 2). Low-dose magnesium gluconate (3 g/day) or placebo was given from the 28th week of gestation to delivery consecutively. RESULTS: 4% of the pregnant women developed PIH after magnesium gluconate treatment, which was substantially lower than that in the control group (16%) (P < 0.05). In the treatment group 2, women showed higher concentration of 6-keto-prostaglandin F1 alpha (PGF1a) and 6-keto-/thromboxane B2(TXB2) (P/T) ratio than that of the control group 2. Moreover, TXB2 level was lower than that in the control group 2. In the treatment group 1 women showed higher ratio of P/T than that of the control group 1. There were no significant differences of serum magnesium concentration among all groups. CONCLUSION: Low-dose magnesium gluconate may efficiently prevent PIH in high risk women. The mechanism of action of magnesium gluconate probably involves to keep the balance of PGI2 and TXA2, but not associates with serum magnesium level.

6-Ketoprostaglandin F1 alpha↗

PubMed1996

Gamma radiation effect on vascular smooth muscle cells in culture.

PURPOSE: Prior work in our laboratory demonstrated that external gamma irradiation administered within 48 h following balloon catheter carotid artery injury in rats produced a marked inhibition of intimal hyperplasia and restenosis. The current study used smooth muscle cells (SMC) in vitro to examine the radiation dose response and to investigate the cellular mechanism by which radiation inhibits SMC proliferation. METHODS AND MATERIALS: Quiescent rat aortic SMC in plasma were refed with whole blood serum to stimulate synchronous proliferation and immediately irradiated with single fraction doses of 1.25-20 Gy. RESULTS: Comparison between a micronucleus assay and a clonogenic assay indicated a dose-dependent inhibition of SMC growth, with an ED50 at 2-3 Gy. The micronucleus assay also demonstrated a dose-dependent increase in apparent chromosomal damage at 72 h after irradiation. Inhibition of SMC growth by radiation did not correlate with changes in intracellular or released mitogenic activity. Furthermore, there was no evidence of apoptosis in irradiated SMC up to 96 h after treatment. CONCLUSION: Radiation likely inhibits SMC proliferation after arterial injury by a dose-dependent mechanism of lethal and/or sublethal cellular injury leading to clonogenic cell death.

Animals↗

PubMed1996

Study of the prevalence of diabetes mellitus in adults in the Shougang Corporation in Beijing.

The aim was to determine the burden of diabetes mellitus (DM) in an urban area of China to aid us in planning preventive measures for those at risk of DM. A survey was conducted among the 29,859 subjects aged between 30 and 64 belonging to 32 units of the Shougang Corporation (a heavy industry enterprise) within the Beijing area. WHO study protocols and diagnostic criteria were used to determine the prevalence of DM and impaired glucose tolerance (IGT). The results showed that the age-adjusted prevalence of DM and impaired glucose tolerance (IGT) was 3.63% and 4.19%, respectively, both increasing with age. Peak prevalence for both occurred in the 60-64 age group. Prevalence showed no difference between the sexes in DM but was higher for females in IGT. Obesity, being overweight, a family history of diabetes mellitus and in women, a history of delivering babies with macrosomia, all correlated closely with the prevalence of DM and IGT. High protein intake was also associated with DM, Smoking had no effect on either DM or IGT. Intellectual workers had a higher incidence of IGT than manual workers. Seventy per cent DM was undiagnosed prior to the survey. This survey, done according to the recommendation of WHO, and including appropriate adjustments, reflects the growing prevalence of DM and IGT in this population. It can be compared with other studies for epidemiological analysis.

Adult↗

PubMed1996

AIDS-associated infections in salivary glands: autopsy survey of 60 cases.

We reviewed the autopsy findings for the submandibular glands of 60 patients with AIDS who were autopsied at the George Washington University Medical Center (Washington, DC) from 1982 to 1992. AIDS-associated infections in the submandibular glands were compared with those in the pancreas and lung. Cytomegalovirus intranuclear inclusions were found in 10 cases, and Pneumocystis carinii infection was found in one case. Disseminated mycobacterial and fungal infections were not identified in the submandibular gland, even in the presence of documented pancreatic and pulmonary infection (P < .05). Overall, the major salivary glands of patients with AIDS are less frequently involved with disseminated opportunistic infections than is either the lung or the pancreas (P < .01 and P < .001, respectively).

AIDS-Related Opportunistic Infections↗

PubMed1996

HIV envelope-directed signaling aberrancies and cell death of CD4+ T cells in the absence of TCR co-stimulation.

HIV-1 infection in CD4(+) T cells initiates a viral cytopathic effect (CPE) that is dependent on the activation of intracellular protein tyrosine kinases (PTK). PTK in T cells are also activated during the course of TCR or CD4 receptor engagement and the manner of receptor engagement may generate signals leading either to cell proliferation, tolerance induction (anergy) or programmed cell death (PCD). We have identified PTK triggered during the interaction of cells stably expressing surface HIV envelope (gp 120/gp41; HIVenv) and CD4(+)T cells, which leads to extensive and rapid individual cell death. We have found that killing is accompanied by tyrosine phosphorylation and activation of the CD4-associated p56(ICK) kinase, and by activation of a second member of the scr family of PTK, p59(fyn) kinase, normally associated with T cell stimulation through the TCR. Interestingly, in contrast with normal T cell signaling, the zeta subunit of the TCR fails to become tyrosine-phosphorylated during signaling accompanying HIV-directed cell killing. Downstream activation of the ZAP-70 PTK also does not occur. Unlike T cell apoptosis triggered by soluble HIVenv glycoproteins, which requires co-stimulation of CD4 and the antigen-specific TCR, T cell killing by membrane-associated HIVenv does not require TCR co-stimulation, because aberrant signaling and cell death are triggered by CD4(+) but TCR- cell lines. These results are the first report where dual activation of the Lck and Fyn PTK does not result in normal downstream signaling through the ZAP PTK, We suggest by analogy to SCID resulting from ZAP-70 mutations, that the dissociation of upstream PTK activation from ZAP-70 signaling contributes to T cell depletion by HIV and to the development of AIDS.

Apoptosis↗

PubMed1996

Multiple organ injuries and failures caused by shock and reperfusion after gunshot wounds.

Experiments were performed to observe the changes of multiple system organ failure (MSOF) and gut barrier function caused by shock and reperfusion after gunshot wounds. Eighteen dogs were divided randomly into two groups. In the experimental group, the dogs were subjected to 60 minutes of shock (40mm Hg), followed by reinfusion of shed blood after hindlimb gunshot wounds. In the control group, the dogs experienced pure gunshot wounds without shock and reperfusion. The results showed that dogs in the experimental group developed multiple system organ injuries or failures compared with the control group. The levels of malondialdehyde (MDA) values in plasma were significantly elevated in the experimental group when compared with preinjury and the control group. Gut flora disorder, bacillus intestinalis overgrowth, and bacterial translocation occurred in the experimental group. The pathological results support the gut barrier function injury. The results indicated that pure gunshot wounds do not easily injure gut barrier function and produce MSOF. Gunshot wounds with shock and reperfusion are capable of causing gut flora disorder, bacillus intestinalis overgrowth, and lead to bacterial translocation, furthermore causing MSOF. Although fluid resuscitation is a potential treatment modality, pathogenically, it can lead to MSOF.

Animals↗

PubMed1996

In vivo effects of tumor necrosis factor-alpha on incised wound and gunshot wound healing.

Recombinant tumor necrosis factor alpha (TNF-alpha) was applied to incised wounds (adult rats, n = 14) and gunshot wounds (dogs, n = 5). The accumulation of RNA and DNA in regenerative tissue, the wound disruption strength (WDS), and histology were examined. The results showed that a single dose of TNF-alpha in saline with highly purified bovine serum albumin increased the WDS and accumulation of RNA and DNA in regenerative tissue in incised wounds 3 days after surgery (p < 0.05). Also, TNF-alpha promoted the inflammatory reaction in the wounded area of gunshot wounds. Histology revealed increased capillary tube-like structures and collagen formation and fibroblast proliferation in both incised and gunshot wounds treated with TNF-alpha. The results indicated that locally applied TNF-alpha benefited the incised and gunshot wound healing. These mitogenic and inflammatory effects of TNF-alpha may be the synergistic effects with other growth factors such as platelet-derived growth factor (PDGF).

Animals↗

PubMed1996

[An experimental study on injury of intestinal immuno-barrier in rat after scald].

A dynamic observation on injury of intestinal immuno-barrier in scalded rat was performed to investigate the relationship between the injury of intestinal immuno-barrier and bacterial translocation. After 40% TBSA third degree scald, a decrease of IgA in intestinal content and the number of CD3+ and CD4+ T lymphocyte, and reduction of IgA coat rate of intestinal bacteria were observed. At the same time, an increase in the incidence of bacterial translocation was detected. The results indicated that intestinal immuno-barrier was damaged and its protective function was weakened after an extensive thermal injury, and it suggested that the injury of intestinal immuno-barrier might play an important role on the development of postburn bacterial translocation and postburn sepsis.

Animals↗

PubMed1996

[Prevalence and risk factors of hypertension and coronary heart disease in the subjects with abnormal glucose metabolism].

The prevalence and risk factors of hypertension and coronary heart disease (CHD) in subjects with abnormal glucose metabolism (AGM) were studied in a population of 29,960 in the Capital Iron and Steel Corporation. The results showed that the prevalences of hypertension and CHD were 37.37% and 9.32% in diabetes group and 29.88% and 6.25% in impaired glucose tolerance group respectively. Both aging and obesity were the risk factors for AGM, hypertension and CHD. Hyperglycemia and hyperlipidemia were related to the occurrence of hypertension and CHD. Our results indicate that the prevalence of CHD and hypertension is significantly increased in AGM subjects, and they have many other risk factors of cardiovascular disease.

Adult↗

PubMed1996

[The effects of intensive DMPA regimen in the treatment of Graves' ophthalmopathy].

35 patients with Graves' ophthalmopathy were treated with DMPA regimen which included dexamethasone (D) 20-30 mg and Methotrexate (M) 15-20 mg i.v. once a week and prednisone (P) 20 mg/d p. o. 4 times a week for 4 weeks followed by addition of azathioprine (A) or 6-MP 75-100 mg/d and the increment of prednisone (20 mg/d) to 5 times a week in the fifth and sixth weeks. The full intensive course of therapy lasted for 6 weeks. If necessary, the similar course of therapy might be repeated. Later on, each patient was mintainted on a therapy with P and A or P and 6-MP for another 1-2 months then the P and A or P and 6-MP for another 1-2 months, and then the P and A or 6-MP were tapered and finally discontinued at the end of sixth month. The symptoms and signs of the opthalmopathy were evaluated blindedly at the beginning and the end of the first and second courses of the therapy by two ophthalmologists. The results showed that the symptoms and signs were significantly improved in 33 (94.3%) cases. A decrease of eyeball protrusion of 1.22 +/- 1.15 and 1.28 +/- 1.15 mm in the left and right eyes respectively was shown by eophthalmometry reading (both P < 0.0005, compared with before and after the therapy). The decrease of exophthalmos was more remarkable in the cases with ophthalmopathy for < or = 1 year than that > 1 year. 11/22 patients recovered their ability to close eyes adequately. The diplopia was corrected in 8/15 cases. The mobility of eye ball returned to normal in 5/15 cases. Exposed lesion and/or ulceration of the cornea found in 7 patients were cured. Serious side and/or toxic effects of the drugs were not present during the course of therapy. It is suggested that DMPA regimen is an effective, safe and cheap approach to the treatment of Graves' ophthalmopathy.

Adult↗

PubMed1996

[A study of insulin sensitivity and its related factors in patients with non-insulin dependent diabetes mellitus and impaired glucose tolerance].

In order to evaluate insulin sensitivity and its related factors in abnormal glucose tolerance, 572 cases of non-insulin dependent diabetes mellitus (NIDDM), 647 cases of impaired glucose tolerance (IGT) and 543 normal controls were studied. The results showed that fasting insulin levels (FIns) and the prevalence of hyperinsulinemia were higher in NIDDM than that in IGT and higher in IGT than that in normal controls (P < 0.01). Insulin sensitivity index (ISI) [-ln(FInx x fasting blood glucose)] ranked from high to low in the order of normal controls, IGT subjects, newly-diagnosed NIDDM patients and patients with known NIDDM (P < 0.01). In each group ISI was smaller in obese subjects or patients than in non-obese ones. Mono-factor analysis demonstrated that ISI in each group was negatively related to body mass index (BMI) and positively related to high density lipoprotein (HDL)-cholesterol. ISI in NIDDM and IGT group was negatively related to blood pressure. Multiple analysis showed that the ISI had significantly negative correlation with BMI and some correlation with blood pressure and blood lipids. In conclusion, the patients with abnormal glucose tolerance had hyperinsulinemia and insulin resistance. ISI was related to some risk factors of vascular diseases.

Body Mass Index↗

PubMed1996

[Transsphenoidal microsurgery for pituitary adenoma: analysis of 3 fatal cases].

To prevent severe postoperative complications and increase the survival rate of patients with pituitary adenoma after transsphenoidal microsurgery, 3 fatal cases were analysed in terms of clinical features and caused of death. They included (1) the too deeply inserted suction apparatus with resultant midbrain damage; (2) bleeding from residual tumor into aphragma sellae and dura mater, entering the subarachnoid, causing spasm of the brain vessels. In order to avoid complication, it is necessary to follow strictly the rules for transsphenoidal microsurgery and improve surgical skills.

Adenoma↗

PubMed1995

Human immunodeficiency virus 1 envelope-initiated G2-phase programmed cell death.

Despite intensive investigation, no clearly defined mechanism explaining human immunodeficiency virus (HIV)-induced cell killing has emerged. HIV-1 infection is initiated through a high-affinity interaction between the HIV-1 external envelope glycoprotein (gp120) and the CD4 receptor on T cells. Cell killing is a later event intimately linked by in vitro genetic analyses with the fusogenic properties of the HIV envelope glycoprotein gp120 and transmembrane glycoprotein gp41. In this report, we describe aberrancies in cell cycle regulatory proteins initiated by cell-cell contact between T cells expressing HIV-1 envelope glycoproteins and other T cells expressing CD4 receptors. Cells rapidly accumulate cyclin B protein and tyrosine-hyperphosphorylated p34cdc2 (cdk1) kinase, indicative of cell cycle arrest at G2 phase. Moreover, these cells continue to synthesize cyclin B protein, enlarge and display an abnormal ballooned morphology, and disappear from the cultures in a pattern previously described for cytotoxicity induced by DNA synthesis (S phase) inhibitors. Similar changes are observed in peripheral blood mononuclear cells infected in vitro with pathogenic primary isolates of HIV-1.

Apoptosis↗

PubMed1995

Cardiologists' practices compared with practice guidelines: use of beta-blockade after acute myocardial infarction.

OBJECTIVE: Our purpose was to measure cardiologists' level of adherence to guidelines for long-term use of beta-adrenergic blocker therapy after acute myocardial infarction. BACKGROUND: Beta-blocker therapy after acute myocardial infarction has been shown to reduce the incidence of reinfarction and associated mortality. To learn about cardiologists' use of this therapy after hospital discharge and their level of adherence to American College of Cardiology guidelines, we analyzed insurance claims from 17 network-model health plans located throughout the United States. METHODS: The study group included 150 cardiologists who had contracts with one of the health plans and their 280 patients who were plan members (excluding Medicare enrollees) and received inpatient treatment for acute myocardial infarction that did not include revascularization during 1992. These patients accounted for 307 separate hospital admissions. Insurance claims were used to measure beta-blocker usage and to identify possible contraindications. RESULTS: Forty-three percent of the cases (131 of 307) involved apparent deviations from the guidelines: 11% of cases (35 of 307) involved possible errors of commission (beta-blocker given in the presence of a contraindication) and 31% (96 of 307) errors of omission (beta-blocker not given in the absence of a contraindication). Of the 185 patients who were eligible for the therapy (no contraindications), only 48% (89 of 185) were treated. CONCLUSIONS: Cardiologists currently exhibit a low level of compliance with their specialty's guidelines for postinfarction beta-blockade. Slightly fewer than 50% of the study patients who were eligible for treatment actually received a beta-blocker after hospital discharge. This result, combined with the drug's known level of effectiveness in preventing recurrent myocardial infarction, suggests that increased use could avert approximately 1,900 deaths annually nationwide.

Adrenergic beta-Antagonists↗

PubMed1995

Auxin-binding protein 1 does not bind auxin within the endoplasmic reticulum despite this being the predominant subcellular location for this hormone receptor.

Auxin-binding protein 1 (ABP1) is a unique hormone receptor because it resides primarily in the lumen of the endoplasmic reticulum (ER); however, two lines of evidence presented here suggest that ABP1 does not bind auxin within the endoplasmic reticulum, despite its predominant location there. First, ABP1 cannot be photolabeled in intact cells that have accumulated the auxin and photolabeling reagent 5-[7-3H]azidoindole-3-acetic acid, indicating either that auxin is excluded from the ER and is not available for photolabeling to ABP1 or that binding conditions within the ER lumen are insufficient for photolabeling. Second, at the pH of the ER lumen, auxin binding to ABP1 is not detectable. The pH estimate of the ER lumen is based on an indirect assay, which indicates that the pH is closer to pH 7 than to the binding optimum of pH 5.5. These results indicate that ABP1 does not bind auxin within the ER and point to a site of action that is post-ER. The effect of auxin on its trafficking from the ER was tested in an animal expression system. ABP1 expressed at high levels in COS7 cells is efficiently retained in the ER lumen and is not secreted even in the presence of 190 microM indole-3-acetic acid, an auxin concentration that is 40 times above the Kd for indole-3-acetic acid binding to ABP1.

Animals↗

PubMed1995

Selection of novel exon recognition elements from a pool of random sequences.

A 20-nucleotide sequence close to the 3' end of the internal exon of a model two-intron, three-exon pre-mRNA (DUP184 [Z. Dominski and R. Kole, J. Biol. Chem. 269:23590-23596, 1994]) was replaced by a random 20-mer, resulting in a pool of pre-mRNAs which, like the initial DUP184 construct, were spliced in vitro by a pathway leading to predominant skipping of the internal exon. The randomized pre-mRNAs were subjected to a selection protocol, resulting in a pool enriched in pre-mRNAs that efficiently included the internal exon. Isolation and sequencing of a number of clones corresponding to the selected pre-mRNAs showed that two classes of sequences were selected from the initial pool. Most abundant among these were sequences with purine tracts similar to those in the recently identified exon-splicing enhancers while a smaller class included sequences lacking discernible purine tracts within the 20-nucleotide region. Splicing of selected pre-mRNAs showed that the purine tracts vary in their ability to promote exon inclusion and, more important, that sequences lacking purine tracts stimulate inclusion of the internal exon as efficiently as their purine-rich counterparts. The latter result indicates the existence of a novel class of exon recognition sequences or splicing enhancers.

Base Composition↗

PubMed1995

Expression and regulation of steroid 5 alpha-reductase in the urogenital tract of the fetal rat.

Two androgens, testosterone and dihydrotestosterone, are required for the development of the male urogenital tract in the rat. Testosterone is secreted by the fetal testes and is thought to elicit differentiation of the Wolffian ducts into seminal vesicles, vas deferens, and epididymides. Testosterone is converted into dihydrotestosterone by steroid 5 alpha-reductase in the urogenital tract, and this conversion is necessary for the differentiation of the prostate and external genitalia. Genes encoding two 5 alpha-reductase isozymes, designated type 1 and type 2, have been identified. We examined the expression and regulation of these genes on days 17-21 in the urogenital tracts of male and female fetuses. Expression of the type 1 gene predominated in epithelial cells, whereas type 2 gene expression was limited to mesenchymal cells. Surprisingly, this expression pattern was detected in both testosterone-dependent and dihydrotestosterone-dependent anlagen of the urogenital tract and was the same in both male and female fetuses. Furthermore, transcripts encoding the two isozymes were present in their respective cell types before the overt differentiation of internal genitalia. Androgens stimulated expression of the type 2 gene in the urogenital tracts of both sexes, but did not effect expression of the type 1 gene or the cell type-specific expression patterns of the 5 alpha-reductase genes. In the adult prostate, 5 alpha-reductase gene expression is under feedforward control, in which the product of the enzyme, dihydrotestosterone, stimulates the expression of the gene. However, no evidence for feedforward regulation of either 5 alpha-reductase gene was detected in the fetus.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗