Biomedical subjects

Shan-Tair Wang

Publications and source records attributed to Shan-Tair Wang.

9 recordsLinked to original sources

PubMed2003

Identification of calcineurin as a key signal in the extinction of fear memory.

Memory extinction refers to a gradual decrease of the previously acquired response when exposed to conditional stimulus without pairing with unconditional stimulus. Here we show for the first time that fear training-induced phosphorylation of specific substrates in the rat amygdala is reduced after extinction trials and is accompanied by an increase in the protein level and enzymatic activity of calcineurin. In parallel, calcineurin inhibitors prevented extinction-induced protein dephosphorylation as well as extinction of fear memory. Thus, extinction training increased phosphatase activity likely via an expression of calcineurin. Calcineurin then created a negative-feedback loop and directly or indirectly dephosphorylated specific substrates, which, in their phosphorylated state, were required for memory consolidation. Accordingly, in our experimental condition, extinction could be ascribed at least in part to a weakening of the original signaling.

Amygdala↗

PubMed2003

Cognitive function variations in postmenopausal women treated with continuous, combined HRT or tibolone. A comparison.

OBJECTIVE: To compare cognitive function in postmenopausal women receiving continuous hormone replacement therapy and those receiving tibolone. STUDY DESIGN: This was a 6-month, prospective, single-blind, single center, randomized study. A total of 50 healthy, postmenopausal women were enrolled. In the end, 40 women completed the 6-month follow-up. One group (23 subjects) received conjugated equine estrogens (CEE), 0.625 mg/d, and medroxyprogesterone acetate (MPA), 5 mg/d. The other group (17 subjects) received tibolone, 2.5 mg/d. Their serum estradiol levels and Cognitive Abilities Screening Instrument (CASI) and Mini-Mental State Examination (MMSE) scores were obtained before starting and after 3 and 6 months of treatment. RESULTS: There was a significant increase in the serum estradiol level in the CEE + MPA group, especially after 3 months of treatment, but there was no increase in the estradiol level in the tibolone group. The CASI and MMSE scores of the CEE + MPA group and the tibolone group after 3 and 6 months of treatment showed no significant difference between the two groups apart from the MMSE at the 3-month follow-up. We saw an increasing trend in CASI and MMSE scores after treatment in both groups; however, the increases were not statistically significant. The rate of increase of both CASI and MMSE scores in the CEE + MPA group was greater than in the tibolone group, though the difference was not significant. CONCLUSION: This preliminary study demonstrated that both CEE + MPA and tibolone can preserve cognitive function and may be able to prevent cognitive decline in postmenopausal women during short-term treatment. Our results also show that continuous, combined CEE + MPA seems to be marginally more effective than tibolone in improving cognitive processes; however, long-term study is needed to follow-up such effect.

Cognition↗

PubMed2002

Serum tissue polypeptide specific antigen as a noninvasive prognostic indicator for early recurrence of hepatocellular carcinoma after curative resection.

BACKGROUND: Serum tissue polypeptide specific antigen (TPS) is a useful cell proliferation marker in diagnosing and monitoring patients with a variety of malignancies. The objective of this study was to determine the usefulness of serum TPS as a noninvasive prognostic factor for early recurrence of hepatocellular carcinoma (HCC) after patients undergo curative resection. METHODS: Serum TPS levels were measured by monoclonal TPS immunoradiometric assay in 54 patients shortly before they underwent curative resection for HCC. The recurrence time was correlated with the TPS level and with other prognostic factors using the log-rank test in univariate analysis and a Cox regression in multivariate analysis. Receiver operating characteristic analysis was performed to examine the power of the various prognostic factors to distinguish between patients with recurrent tumors and patients who were disease free. RESULTS: Patients who had higher levels of TPS (>or= 150 U/L) had earlier recurrences compared with patients who had lower levels of TPS (< 150 U/L; P = 0.016) in univariate analysis. Tumor size, the number of tumors, portal vein invasion, and the resection margins also were associated significantly with the time to tumor recurrence (P = 0.015, P = 0.004, P = 0.003, and P = 0.003, respectively). Serum alpha-fetoprotein was not a significant risk factor for tumor recurrence. In multivariate analysis, the TPS level, tumor size, and resection margins were independent prognostic factors (P = 0.025, P = 0.018, and P = 0.016, respectively). The inclusion of TPS in addition to tumor size and resection margins increased the rate of corrective prediction from 0.72 to 0.80. CONCLUSIONS: The current study demonstrated that the preoperative serum TPS level was a significant factor in predicting early recurrence of HCC after curative resection. Patients with high serum TPS levels warrant more aggressive treatment and close follow-up after they undergo tumor resection.

Adult↗

PubMed2002

Efficacy and cost-effectiveness of influenza vaccination of the elderly in a densely populated and unvaccinated community.

For economic reasons, the few influenza vaccination programs seen in developing countries are aimed at the high-risk elderly. To evaluate its efficacy and cost-effectiveness, we conducted a 2-month influenza vaccination campaign in southern Taiwan's A-Lein township for all the elderly. Significant differences in hospitalization and mortality between the vaccinated and unvaccinated groups were found. Age, sex, and risk group were significant for hospitalization and mortality, but only vaccination was significant for prevention. Savings for each person vaccinated were at least three times the cost of vaccination. We strongly recommend that all the elderly-not only high-risk elderly--receive an annual influenza vaccination.

Aged↗

PubMed2002

Smoking and alanine aminotransferase levels in hepatitis C virus infection: implications for prevention of hepatitis C virus progression.

BACKGROUND: Alcohol consumption is a well-known risk factor for elevated ALT levels, but the role of cigarette smoking is unclear. METHODS: We collected a cross-sectional sample of 6095 inhabitants 35 years or older in a community with hyperendemic hepatitis B and C virus infections. We assayed levels of serum alanine aminotransferase (ALT), hepatitis B surface antigen (HBsAg), and anti-hepatitis C virus antibody (anti-HCV). Multivariate logistic regression was performed to determine the factors for elevated ALT levels (> or =40 U/L) among people with different hepatitis infection statuses. RESULTS: Prevalence of elevated ALT levels in individuals who were seronegative for both infections or seropositive for HBsAg or anti-HCV was 3.9%, 11.1%, and 30.8%, respectively. Subjects with elevated ALT levels were more likely to be seropositive for anti-HCV, male, and seropositive for HBsAg; to drink alcohol; to smoke; and to have undergone blood transfusion (P<.05). An association was found between elevated ALT levels and the consumption of cigarettes and alcohol among anti-HCV-seropositive subjects. In multivariate logistic analyses, alcohol consumption (odds ratio [OR], 2.2; 95% confidence interval [CI], 1.2-4.1) and smoking (OR, 1.8; 95% CI, 1.1-2.7) were significantly associated with elevated ALT levels among anti-HCV-seropositive subjects, but no such association was found among HBsAg-seropositive subjects. The odds of elevated ALT levels were 7 times higher (95% CI, 2.7-18.8) for the anti-HCV-seropositive patients who smoked 1 or more packs of cigarettes per day and frequently drank alcohol than for those who did not. CONCLUSIONS: Smoking and alcohol consumption are independently associated with elevated ALT levels among anti-HCV-seropositive individuals but not among HBsAg-seropositive individuals. Patients who are seropositive for anti-HCV are strongly advised not to smoke and drink alcohol to reduce the possible risk for aggravating the liver dysfunction.

Adult↗

PubMed2002

The changes in caregiver burden following nursing home placement.

This longitudinal study explored changes in perceived burden among Taiwanese family caregivers (n=77) from nursing home placement of an elder to four months postadmission. Higher burden at placement was related to the level of dependence of the care recipients (p=0.004), or caregiver's poor health (p<0.01). After nursing home placement for four months, global burden decreased (p<0.01) contributed primarily by lessened burden in three sub-scales: lack of family support, impact of schedule and impact of health. Burden scores on caregiver esteem and impact of finances were not decreased after placement. Duration of caregiving was the only demographic factor predicting change in global burden (p<0.001). Changes in impact on finances, and impact on health were, respectively, predicted by the perceived health (p=0.005), and religious preference (p=0.01). These results provide valuable information to healthcare providers for an understanding of the changes of caregiving burden after nursing home placement and the correlates of these changes, which may help devise an appropriate policy for alleviating the caregiver's burden.

Aged↗

PubMed2002

Serum CA-125 in preoperative patients at high risk for endometriosis.

OBJECTIVE: To investigate the factors contributing to the elevated level of CA-125 in endometriosis and to study whether CA-125 assay is useful to identify women who require preoperative bowel preparation. METHODS: A total of 685 women undergoing surgery for endometriosis between July 1988 and June 1999 were studied. Preoperative serum CA-125 levels were compared between various pelvic conditions using F statistics. Multiple regression was employed to determine significant correlates of elevated serum CA-125, and the receiver operating characteristic curve was applied to assess the utility of serum CA-125 in preoperative preparation. Based on the two-sample Student t test, the sample size required to detect a difference in mean serum CA-125 levels of one-half of one standard deviation with a power of 90% when the sample size ratio of the two groups was 1:50 was 675 with a significance level of 5%. RESULTS: The mean serum CA-125 levels (IU/mL) for American Society of Reproductive Medicine stages I, II, III, and IV endometriosis were 18.8 +/- 0.9, 40.3 +/- 2.8, 77.1 +/- 3.5, and 182.4 +/- 14.0, respectively. CA-125 levels were significantly increased with advanced stages (P <.001, F test). Furthermore, serum CA-125 levels were significantly higher in patients with more extensive adhesions to the peritoneum, omentum, ovary, fallopian tube, colon, and cul-de-sac, or with ruptured endometrioma (P <.001, F test). We then classified patients with at least one of the three factors including dense omentum adhesion, ruptured endometrioma, and complete cul-de-sac obliteration as the high-risk group that required preoperative bowel preparation, and the others as the low-risk group. Receiver operating characteristic curve analyses set a cutoff point of 65 IU/mL, which gave a sensitivity of 76%, a specificity of 71%, a positive predictive value of 76%, and a negative predictive value of 93.2%. CONCLUSION: Our results suggest that preoperative CA-125 assay is useful to decide which women should receive preoperative bowel preparation. Endometriosis patients with preoperative CA-125 levels higher than 65 IU/mL are at high risk for severe pelvic adhesions that warrant thorough preoperative bowel preparation.

Adult↗

PubMed2002

Serum leptin concentrations of patients with sequential thyroid function changes.

BACKGROUND: Leptin, a recently discovered protein produced in adipocytes, regulates body weight by suppressing food intake and/or increasing energy expenditure. Thyroid hormones, which increase the basal metabolic rate and thermogenesis, have been reported to be one of leptin's regulating factors because alternations in thyroid status might lead to compensatory changes in circulating leptin. OBJECTIVE: The aim of this study was to assess the influence of sequential changes in thyroid function on serum leptin levels. PATIENTS AND METHODS: The thyroid function status of 65 patients (55 women and 10 men, aged 40.6 +/- 15.2 years, mean +/- SD) with differentiated thyroid cancer who had received near-total thyroidectomy was studied before I-131 ablation therapy and after 2-4 and 6 months of levo-thyroxine suppressive therapy. Thirty-three (26 women, seven men; aged 41.0 +/- 10.4 years, mean +/- SD) of them were found to have become hypothyroid, then euthyroid and subsequently subclinically hyperthyroid. Their body mass index (BMI), body fat (%BF) by electrical bioimpedance, thyroid function and fasting serum leptin in these states were assessed and compared to those of 38 controls (30 women, eight men, aged 40.2 +/- 11.3 years, mean +/- SD). The controls had no past history or family history of thyroid diseases, and had the same range of BMI, between 20 and 30 kg/m2, as the patients. RESULTS: No difference in serum leptin levels was found between patients and controls with comparable age, sex, and BMI distribution in the euthyroid state. Using a repeated measures anova, tests of TSH, free T4 (FT4), BMI,%BF and leptin were performed on the 33 patients with sex as a grouping factor and thyroid state as a time factor. The sex difference for %BF and leptin proved to be statistically significant (P < 0.0001, and P = 0.0003, respectively). Serum leptin levels increased significantly from the hypothyroid to the subclinical hyperthyroid state (P < 0.0001) with a more pronounced increase found in females than in males (P = 0.03). Change of BMI during sequential thyroid function alterations was significant (P = 0.04) while change in %BF was not significant (P = 0.09). Pearson correlation analysis showed that serum leptin levels significantly correlated with BMI, %BF, FT4, and TSH (all P < 0.05). Using the generalized estimating equations, multivariate regression analysis revealed that FT4 was a statistically independent predictor for serum leptin (P < 0.0001). While other parameters were held constant, the mean serum leptin level increased by 1.47 units when serum FT4 was increased by one unit. CONCLUSION: In conclusion, our data indicate that circulating thyroid hormone plays a relevant role in regulating leptin metabolism independent of BMI and body fat.

Adult↗

PubMed2002

Relative impact of low-density lipoprotein-cholesterol concentration and insulin resistance on carotid wall thickening in nondiabetic, normotensive volunteers.

The relative effect of an increase in low-density lipoprotein-cholesterol (LDL-C) concentration, as compared with insulin resistance and its manifestations, on intimal medial thickening (IMT) of the common carotid artery was defined in 72 healthy men and women. Insulin-mediated glucose disposal was quantified by the insulin suppression tests, in which the height of the steady-state plasma glucose (SSPG) concentration during the last 30 minutes of a 180-minute infusion of octreotide, insulin, and glucose provides an estimate of insulin resistance. IMT was determined by high-resolution B-mode ultrasonography. Univariate analyses defined statistically significant correlation coefficients between IMT and LDL-C concentration (r =.25, P <.05), SSPG concentration (r =.32, P <.01), triglycerides (TG) (r =.25, P <.05), and high-density lipoprotein-cholesterol (HDL-C) (r = -.28, P <.05) concentrations (changes associated with insulin resistance) and ratio of waist-to-hip girth (r =.29, P <.05). When forward step-wise linear regression analysis was used, concentrations of SSPG, LDL-C and HDL-C all emerged as independent predictors of IMT (P <.05). Furthermore, the magnitude of their relationship to IMT values was comparable. These results provide evidence that insulin resistance is as significant a predictor of degree of atherogenesis (estimated by IMT) of the common carotid artery as a high LDL-C concentration.

Adult↗