Biomedical subjects

Y Zhao

Publications and source records attributed to Y Zhao.

At least 361 records · Page 20Linked to original sources

PubMed2000

[Refined chromosome assignment of human novel H-RalGDS gene on chromosome 9q34.1 by using radiation hybrid genebridge 4 panel].

OBJECTIVE: Refined chromosome assignment of a novel Ras-related H-RalGDS gene (the human homology of rat RalGDS, Ral guanine nucleotide dissociation stimulator recently cloned and characterized by our laboratory) by using human/rodent radiation somatic cell hybrid panel GB4. METHODS: According to the sequence of the 3'-untranslated region of H-RalGDS cDNA, forward and reverse primers were designed and used to amplify the human/rodent somatic radiation hybrid Genebridge 4 panel. The PCR result of each cell line of the panel was scored in a certain way and put into the related internet site of WI/MIT Radiation Hybrid Mapper for RH mapping and comprehensive analysis. RESULTS: The H-RalGDS gene was successfully localized to the framework of chromosome 9. After referring to literature and further integrated mapping analysis of the physical, genetic linkage and cytological mappings, the gene was assigned precisely between the markers SURF5 and RPL7A which had already been assigned to human chromosome 9q34.1. CONCLUSION: The localization of H-RalGDS not only contributed much to the construction of refined gene map and cytogenetic map within the region of chromosome 9q34, but also made clear that RH mapping of human novel genes is a simple, convenient and reliable method which can provide even more genetic information of genes within chromosomal regions.

Animals↗

PubMed2000

Serum leptin concentrations in women during gonadotropin stimulation cycles.

OBJECTIVE: To determine whether elevated follicular steroid levels during gonadotropin stimulation cycles are associated with altered circulating leptin concentrations. STUDY DESIGN: Sequential serum samples were collected from women (N = 37) undergoing luteal phase GnRH agonist + FSH treatment cycles prior to oocyte retrieval for in vitro fertilization. Leptin concentrations in serum were measured by radioimmunoassay and compared with serum estradiol, testosterone and dehydroepiandrosterone sulfate (DHEAS) levels. RESULTS: Serum leptin concentrations during stimulated cycles were variable between patients and correlated positively (r = .556, P < .01) with body mass index. Serum leptin levels correlated positively (r = .185, P < .05) with estradiol concentrations across all days. Mean serum leptin concentrations on the day gonadotropin treatment began (baseline, 12.9 +/- 2.0 ng/mL) were lower (P < .0001) than on the day peak estradiol levels were reached (18.4 +/- 2.3 ng/mL). Serum leptin concentrations also correlated with DHEAS levels (r = .214, P < .05) but did not correlate with testosterone or the estradiol:testosterone ratio. CONCLUSION: Gonadotropin stimulation in women is associated with elevated leptin levels, consistent with an interaction between the reproductive axis and leptin secretion and/or clearance.

Adult↗

PubMed2000

Changes in cytokine (IL-8, IL-6 and TNF-alpha) levels in the amniotic fluid and maternal serum in patients with premature rupture of the membranes.

PURPOSE: To study the changes in interleukin-6 (IL-6), interleukin-8 (IL-8) and tumor necrosis factor-alpha (TNF-alpha) levels in patients with premature rupture of the membranes (PROM). METHODS: A total of 46 normal term pregnant women served as controls and 46 women with PROM were enrolled for study. Maternal serum and amniotic fluid IL-6, IL-8 and TNF-alpha levels were determined by enzyme-linked immunosorbent assay and a sensitive radioimmunoassay, respectively. RESULTS: The maternal serum IL-6 and IL-8 levels and amniotic fluid IL-6, IL-8 and TNF-alpha levels were higher than those of controls, and the differences were significant between the two groups (p < 0.05). Although the levels of TNF-alpha in maternal serum were higher than that of controls, the difference was not significant. There were significant relationships between the levels of IL-6, IL-8 and TNF-alpha and the duration of PROM. The longer the duration of PROM, the higher the levels of maternal serum and amniotic fluid IL-6, IL-8 and TNF-alpha were. There were 12 cases of clinical chorioamnionitis, and the levels of IL-6, IL-8 and TNF-alpha in the maternal and amniotic fluid were higher than that of those without chorioamnionitis (p < 0.05). CONCLUSION: Determining cytokines (IL-6, IL-8 and TNF-alpha) is a valuable clinical method for identifying chorioamnionitis in patients with PROM.

Adult↗

PubMed2000

A trial of ademetionine in the treatment of intrahepatic biliary stasis viral hepatitis.

OBJECTIVE: To observe the efficacy and safety of ademetionine in the treatment of viral hepatitis with intrahepatic biliary stasis. METHODS: In this series, 110 patients with viral hepatitis associated intrahepatic biliary stasis were randomly divided into Groups A and B. Patients in Group A received ademetionine for four weeks. Patients in Group B received potassium magnesium aspartate for four weeks. RESULTS: In Group A, at the end of treatment, the effective rate for skin pruritus in patients with cholestatic hepatitis was 86.67% (13/15), and the effective rate for skin pruritus and anorexia were 88.24% (15/17) and 82.35% (14/17), respectively in patients with chronic hepatitis combining intrahepatic cholestasis, which were significantly higher than that in Group B (P<0.05). STB, SCB, TBA, ALT and AST were lower in Group A than Group B (P<0.05). The decrease of ALP and the increase of albumin after treatment were more significant in Group A than in Group B (P<0.05). CONCLUSION: Ademetionine has better efficacy than potassium magnesium aspartate in the treatment of patients with cholestatic viral hepatitis.

Adolescent↗

PubMed2000

DNA testing for fragile X syndrome in 255 males from special schools in Singapore.

INTRODUCTION: Fragile X syndrome, the most common cause of inherited mental retardation, results from unstable expansion of a trinucleotide (CGG)n repeat in the FMR1 gene. Phenotypic expression is variable making clinical diagnosis difficult, while diagnosis by Southern blotting is relatively expensive and labour intensive. The prevalence in Singapore has not been studied. MATERIALS AND METHODS: We developed a rapid screening test using a PCR analysis. We studied 255 males with unexplained cause for learning difficulties from 8 special schools. A clinical scoring system based on characteristic features described was devised. RESULTS: PCR analysis showed absence of the band for the normal allele in 11 samples, 6 of which were confirmed by Southern blotting to be positive for FMR1 expansion, giving a 2% false-positive rate with PCR. Sensitivity of the PCR test was evaluated by performing Southern blotting in all PCR-normal samples; all of which were confirmed to be normal. This PCR test was shown to be highly reproducible. Clinical criteria were not predictive. CONCLUSIONS: Six (2.4%) new cases of fragile X syndrome were detected. There is a need to incorporate fragile X testing in routine screening of patients with developmental delay and learning difficulties. The use of PCR could eliminate the need for Southern blotting in up to 95% of cases. PCR analysis provides a simple, reliable and rapid tool for screening.

Adolescent↗

PubMed2000

[Stress-corrosion test of TIG welded CP-Ti].

In this study TIG (Tungsten Inert Gas) welded CP-Ti were subjected to stress-corrosion test under 261 MPa in artificial saliva of 37 degrees C for 3 months. No significant difference was noted on mechanical test (P > 0.05). No color-changed and no micro-crack on the sample's surface yet. These results indicate that TIG welded CP-Ti offers excellent resistance to stress corrosion.

Biocompatible Materials↗

PubMed2000

[Plasma total homocysteine and pulmonary thromboembolism].

OBJECTIVE: To investigate whether the elevated plasma homocysteine increases the risk of pulmonary thromboembolism in the Chinese population. METHODS: Sixty-nine patients with pulmonary thromboembolism and 90 sex- and age-matched healthy controls were recruited, and the patients were diagnosed using lung ventilation/perfusion scan and/or ultrafast CT as well as medical history. The concentration of plasma total homocysteine (tHcy) was measured with high performance liquid chromatography and environmental factors were collected. RESULTS: No significant difference was seen in family history of pulmonary thromboembolism and cardiovascular diseases, cigarette smoking, alcoholic drinking, oral contraceptive and body mass index between cases and healthy controls. The concentration of plasma tHcy in cases was significantly higher than that in healthy controls (16.60 mumol/L +/- 1.75 mumol/L vs 12.48 mumol/L +/- 1.47 mumol/L; t = 3.821, P < 0.05), and adjusting for environmental factors did not change the significance. The plasma tHcy in the isolated pulmonary thromboembolism patients was lower than that in the patients who had lower limb deep venous thrombosis, but no significant difference was found. Compared with normal plasma tHcy, hyperhomocysteinemia was associated with a 4.99-fold risk of pulmonary thromboembolism. CONCLUSION: Our results show that the elevated plasma tHcy increases the risk of pulmonary thromboembolism, and hyperhomocysteinemia is an independent risk factor of pulmonary thromboembolism in the Chinese population.

Adult↗

PubMed2000

Changes in genioglossus muscle activity in obstructive sleep apnea patients with and without snore guard.

OBJECTIVE: To study the effect of Snore Guard on the genioglossus (GG) muscle activity of obstructive sleep apnea (OSA) patients. MATERIALS AND METHODS: Fifteen male patients with mild to severe OSA were diagnosed by overnight polysomnographic studies, and were reexamined after using Snore Guard for 2-6 months. The difference in GG muscle activity was then compared. RESULTS: The overnight GG muscle activity decreased significantly with Snore Guard. The levels of GG muscle activity during awake quiet breath and obstructive sleep apnea were higher than in sleepstate quiet breath without Snore Guard, and significantly decreased with Snore Guard. The increase in GG muscle activity during sleepstate quiet breath with Snore Guard was not statistically significant. The fluctuating GG muscle activity without Snore Guard was effectively improved by treatment with the appliance. CONCLUSION: The effect of Snore Guard on OSA patients is a mechanical enlargement of upper airway volume. The genioglossus muscle is passive during treatment.

Adult↗

PubMed2000

[The relationship between dental fluorosis and dietary pattern among Tibetan children in natural protective areas of Mount Qomolangma].

OBJECTIVE: To study the relationship between dietary pattern and dental fluorosis among Tibetan children in natural protective areas of Mount Qomolangma. METHODS: Environmental fluorine levels, dietary pattern and occurrence of dental fluorosis among children in Xieger town, Dingri County and Zhangmu town, Nielamu County, were studied. RESULTS: The total fluorine intake in children was 8.039 mg in Xieger town and the prevalence rate of dental fluorosis was 75.93%. The total fluorine intake and morbidity of dental fluorosis are 2.797 mg and 25.86% respectively in Zhangmu town. CONCLUSION: It suggested that fluorosis of children is related to total fluoride intake.

Adolescent↗

PubMed2000

[Study on parents phenotypes in women with polycystic ovary syndrome].

OBJECTIVE: To explore the parents phenotypes in women with polycystic ovary syndrome (PCOS). METHODS: Clinical data were collected by questionnaires from 139 parents of women with PCOS and from 137 parents of controls with normal menses. It was compared for the distribution of mother's menses irregularity, father's premature balding and parents hypertension by chi-square tests among parents of the PCOS group and of the controls. A multiple Logistic regression model was applied for more detailed analyses. RESULTS: The prevalences of mother's menses irregularity, the incidence of father's premature balding and father's hypertension was significantly higher in PCOS group (38.1%, 19.4% and 30.9%, respectively) than in the controls (3.6%, 5.1% and 16.1%, respectively P < 0.01). The prevalence of mother's hypertension was higher in the PCOS group (23.0%) than in the controls (13.9%), but the difference was not significant (P = 0.06). When mother's menses irregularity, father's premature balding and father's hypertension were entered the Logistic regression model, all the odds ratio (OR) values were still much higher than 1 (P < 0.005). The partial regression coefficients of the three predictors changed little when they were entered the model in turn. The partial regression coefficients for father's age was very small when it entered the model as a possible confounding factor(P > 0.05). The differences between maximum -2log likelihoods used to evaluate the role responsible for the occurrence of PCOS in their daughters indicated that: mother's menses irregularity > father's premature balding > father's hypertension. CONCLUSION: In addition to mother's menses irregularity and father's premature balding, father's hypertension may also be an independent phenotype in families of women with PCOS.

Alopecia↗

PubMed2000

[Congression and regression tree analyses on the outcome of ovulation induction in women with polycystic ovary syndrome].

OBJECTIVE: To investigate the risk factors for failure of ovulation induction in polycystic ovary syndrome (PCOS) patients and establish congression and regression tree (CART) model. METHODS: Sex hormones were measured in 103 PCOS patients and 31 healthy women by radioimmunoassay, oral glucose tolerance test (OGTT) and insulin release test were done as well. Three ovulation induction protocols including clomiphene (CC)/chorionic gonadotrophin (hCG), CC/menotrophins (hMG)/hCG and gonadotrophin releasing hormone agonist(GnRH-a)/hMG/hCG were used for PCOS related infertility. Transvaginal ultrasonography was used for monitoring. The correlation between hormone levels and clinical outcomes was analyzed by CART method. RESULTS: The ovulation rate in patients with 2-hour blood insulin level < or = 68.9 mIU/L during OGTT was 86.9%, which was significantly higher than those with > 68.9 mIU/L (61.9%, P < 0.05). In the model, the insulin and glucose level of 0 min, 60 min during OGTT acted obviously, but estradiol and basal T level did not, the protocol of ovulation induction was not able to enter the model. CONCLUSION: Two hour insulin level during OGTT is the most important factor affecting the outcome of ovulation induction, while the others parameters of glucose and insulin level have useful action too.

Adult↗

PubMed2000

[Expression of alpha 1-4 integrins in hypertrophic scar fibroblasts].

OBJECTIVE: To determine the expression levels of alpha 1-4 integrins in hypertrophic scar fibroblasts and investigate the role that alpha 1-4 integrins may play in the process of hypertrophic scar formation. METHODS: The membrane protein was extracted from hypertrophic scar and normal skin tissues. The content of alpha 1-4 integrins of the membrane protein was detected by immunoblotting method. The locations of alpha 1-4 integrin expression were examined by immunohistochemical stain. RESULTS: 1. Higher concentration of alpha 1-4 integrins was identified in the membrane protein extracted from hypertrophic scar than from normal skin. 2. In normal skin, the expression of alpha 1, alpha 2 and alpha 3 integrins located on the epidermal cell surface but not on the dermal fibroblast surface. In the hypertrophic scar, not only did the epidermal cell surface express alpha 1-3 integrins, but also the fibroblast surface expressed alpha 1-4 integrins. CONCLUSIONS: The expressions of hypertrophic scar fibroblast surface integrins are subjected not only to cell-extracellular matrix adhesion, but also to intracellular/extracellular signal transduction. Integrins may play an important role in regulating much of fibroblast behavior, including growth, differentiation, phenotype, and in scar tissue remodelling.

Adolescent↗

PubMed2000

[Environmental fluorine level in Tibet].

The concentration of fluorine in water, soil, fuel, food, vegetable and tea in Tibetan habitats with different environmental characteristic were measured by ion-specific electrode potentiometer. The results showed that the fluorine concentration in water, soil, fuel, food vegetable, butter tea and Zanba both of them were made from brick teas was 0.06 mg.L-1, 0.45 mg.kg-1, 0.10 mg.kg-1, 0.06-0.33 mg.kg-1, 3.09 mg.L-1 and 3.61 mg.kg-1, respectively. The water-soluble fluorine content in brick tea which came from Sichuan and Yunnan Provinces reached up to 533.89-617.32 mg.kg-1. It is suggested that drinking brick tea may induce fluorosis in Tibetan habitats.

Environment↗

PubMed2000

[Flood prevention function of Panjin wetland at Liaohe delta].

This paper discussed the character of flood, the change of flood disasters and the flood prevention function of Panjin wetland at Liaohe delta. According to the hydrogeological characters of Panjin wetland and its landscape function in flood prevention and disaster reduction, the Panjin wetland was divided into key prevention area, flood ground-stored area, flood discharged area, emergent flood divresion area, and flood prevention and draining area, which might be a reference to the planning of local development.

Disasters↗

PubMed2000

Vasoactive effects of adrenotensin and its interactions with adrenomedullin.

OBJECTIVE: To investigate the vasoactive effects of adrenotensin and the interactions between adrenotensin and adrenomedullin (ADM). METHODS: Isolated rat aortic tension, rat mean arterial pressure and 3H-TdR incorporation of rat vascular smooth muscle cells were measured. Isolated rat aortas were incubated in K-H solution containing adrenomedullin or adrenotensin. The released adrenotensin or adrenomedullin (in incubation medium) from rat aortas was measured by radioimmunoassay. RESULTS: 1 x 10(-8) and 1 x 10(-7) mol/L adrenotensin augmented rat aortic tension in a dose-dependent manner (P < 0.01). An intravenous bolus injection of adrenotensin (2.5 nmol/kg, i.v.) increased the mean arterial pressure by 28% in anesthetized rats (P < 0.01). 1 x 10(-7) mol/L adrenotensin increased 3H-TdR incorporation in cultured rat vascular smooth muscle cells by 55% (P < 0.01). Adrenomedullin inhibited these activities of adrenotensin to different extents. 1 x 10(-9), 1 x 10(-8) and 1 x 10(-7) mol/L adrenotensin decreased adrenomedullin release rates by 19%, 35% and 46%, respectively (P < 0.05 or P < 0.01) and 1 x 10(-8) mol/L adrenomedullin also inhibited adrenotensin release by 45% from rat aorta (P < 0.01). CONCLUSION: Adrenotensin is a novel peptide that elicits the activities of vasoconstriction, pressor effects and induces the proliferation of vascular smooth muscle cells. There is antagonism in vascular activities and reciprocal inhibition in the release between adrenotensin and adrenomedullin. These interactions are manifestations of intramolecular regulation of proadrenomedullin (Pro-ADM).

Adrenomedullin↗

PubMed2000

[Serum lipoprotein(a) in woman with pregnancy induced hypertension].

OBJECTIVE: To examine lipoprotein(a) level in woman with Pregnancy induced hypertension (PIH) to elucidate the effect of it on the pathogenesis of the disease. METHODS: Serum lipoprotein (a) total cholesterol (TC), triglyceride (TG), high density lipoprotein cholesterol (HDL-C) and low density lipoprotein cholesterol (LDL-C) levels were measured in 20 normal pregnant woman (control group) and 32 pregnant woman with PIH (PIH group). The PIH group was further divided into the following subgroup: mild, moderate, and severe PIH. We used a transmission turbidimetry method to measure serum lipoprotein(a). RESULTS: (1) The serum lipoprotein (a) levels were higher in PIH group than that in control group (228 +/- 187 mg/L vs 106 +/- 93 mg/L). (2) The serum lipoprotein (a) levels were higher in all PIH subgroups than that in control. (3) The serum levels of TC, TG, LDL-C in the PIH group were higher than those in control, while the level of HDL-C in the PIH group was lower than that in control (0.98 +/- 0.16 mmol/L vs 1.09 +/- 0.17 mmol/L). CONCLUSIONS: This study has demonstrated that lipoprotein (a) levels are elevated in pregnant woman with PIH and associated with severity of the disease. It may involved in the pathogenesis of PIH.

Adult↗

PubMed2000

Factors influencing the expression of Fas and Fas ligand on newborn murine keratinocytes and fibroblasts.

OBJECTIVE: To investigate the expression of Fas, FasL mRNA and proteins on keratinocytes and fibroblasts, and the influence by retinoid acid (RA) and dexamethasone (Dex). METHODS: RNase protection assay and flow cytometry were used. RESULTS: Fas mRNA was expressed on neonatal murine keratinocytes and was up-regulated by all-trans retinoid acid and down-regulated by Dex. RA and Dex also increased the Fas protein expression on keratinocytes. Newborn murine keratinocytes express FasL mRNA, which was up-regulated by RA and Dex, while its protein expression was moderately induced by RA. Newborn murine fibroblasts also expressed Fas and FasL mRNA, which were up-regulated by the RA and Dex. CONCLUSIONS: The results indicated that RA and Dex might regulate apoptosis of keratinocytes and fibroblasts via the Fas-FasL system.

Animals↗

PubMed2000

Upregulation of drug sensitivity of multidrug-resistant SGC7901/VCR human gastric cancer cells by bax gene transduction.

OBJECTIVE: To investigate the role of bax in a vincristine (VCR)-induced multidrug-resistant (MDR) human gastric cancer cell line, SGC7901/VCR, in which the Bax protein expression level was significantly lower compared with that in parent cells. METHODS: A bax eukaryotic expression vector was constructed and transfected into SGC7901/VCR cells by lipofectamine, and resistant clones were selected by G418. Western blotting detected Bax expression in transfectants. Tetrazolium blue (MTT) assay evaluated the differences in drug sensitivity and cell cycle changes of transfectants were analyzed using flowcytometry (FCM). RESULTS: The bax eukaryotic expression vector was constructed and transfected into SGC7901/VCR cells. Through G418 selection, resistant clones were obtained. Western blotting demonstrated that the expression of Bax protein was markedly increased in bax transduced cells. These cells were more sensitive to adriamycin (ADR) and VCR than mock vector transducted cells. Moreover, bax transfection enhanced ADR-induced apoptosis and VCR-induced G2/M phase arrest of SGC7901/VCR cells. CONCLUSION: Bax was involved in the MDR of SGC7901/VCR cells.

Antineoplastic Agents, Phytogenic↗