307 research outputs found
Lyapunov and Wirtinger inequalities
AbstractIn this paper, we prove the Lyapunov inequality for the second-order linear differential equation (r(t)φ(y′(t)))′+p(t)φ(y(t))=0, where(i)φ(s) = |s|αt-2s, α > 1 is a fixed real number(ii)r(t) and p(t) are integrable on [a, b] with r(t) > 0 on [a, b].On the other hand, a generalized Wirtinger inequality is also given
Inhibition of gap junctional Intercellular communication in WB-F344 rat liver epithelial cells by triphenyltin chloride through MAPK and PI3-kinase pathways
<p>Abstract</p> <p>Background</p> <p>Organotin compounds (OTCs) have been widely used as stabilizers in the production of plastic, agricultural pesticides, antifoulant plaints and wood preservation. The toxicity of triphenyltin (TPT) compounds was known for their embryotoxic, neurotoxic, genotoxic and immunotoxic effects in mammals. The carcinogenicity of TPT was not well understood and few studies had discussed the effects of OTCs on gap junctional intercellular communication (GJIC) of cells.</p> <p>Method</p> <p>In the present study, the effects of triphenyltin chloride (TPTC) on GJIC in WB-F344 rat liver epithelial cells were evaluated, using the scrape-loading dye transfer technique.</p> <p>Results</p> <p>TPTC inhibited GJIC after a 30-min exposure in a concentration- and time-dependent manner. Pre-incubation of cells with the protein kinase C (PKC) inhibitor did not modify the response, but the specific MEK 1 inhibitor PD98059 and PI3K inhibitor LY294002 decreased substantially the inhibition of GJIC by TPTC. After WB-F344 cells were exposed to TPTC, phosphorylation of Cx43 increased as seen in Western blot analysis.</p> <p>Conclusions</p> <p>These results show that TPTC inhibits GJIC in WB-F344 rat liver epithelial cells by altering the Cx43 protein expression through both MAPK and PI3-kinase pathways.</p
Analysis of Surgically Treated Intraspinal Tumors in Southern Taiwan
The medical records of 117 patients with spinal tumors who underwent surgery with pathologic confirmation from January 1999 to April 2004 at Kaohsiung Medical University Hospital were reviewed. Data from this review were compared with those obtained from the same institution 10 years earlier (covering the period 1988-1995) and from other reported series. There were 69 male and 48 female patients aged from 13 to 87 years old (mean age, 51.9). The most common pathologic findings were metastasis in 45.3% (53/117), nerve sheath tumors in 28.2% (33/117), menin-giomas in 12% (14/117) and neuroepithelial tumors in 6% (7/117). The peak ages at diagnosis were 41-50 years and 61–70 years. A slight male predominance was noted for all tumors, except meningiomas. Motor weakness, even paralysis, was the major clinical presentation (64–86%), followed by sensory deficits (50%) and pain (42%). The location of tumors was most often in the thoracic (50.4%; 59/117), lumbosacral (27.4%; 32/117) and cervical spine (22.2%; 26/117) segments. Among the metastatic tumors, the lung (22.6%) and breast (15.1%) were the most common primary sites of origin, followed by unknown origin, the liver (hepatocellular carcinoma), the gastrointestinal tract and the nasopharynx (nasopharyngeal cancer)
Ginsenoside-Rg1 Protects the Liver against Exhaustive Exercise-Induced Oxidative Stress in Rats
Despite regular exercise benefits, acute exhaustive exercise elicits oxidative damage in liver. The present study determined the hepatoprotective properties of ginsenoside-Rg1 against exhaustive exercise-induced oxidative stress in rats. Forty rats were assigned into vehicle and ginsenoside-Rg1 groups (0.1 mg/kg bodyweight). After 10-week treatment, ten rats from each group performed exhaustive swimming. Estimated oxidative damage markers, including thiobarbituric acid reactive substance (TBARS) (67%) and protein carbonyls (56%), were significantly (P < 0.01) elevated after exhaustive exercise but alleviated in ginsenoside-Rg1 pretreated rats. Furthermore, exhaustive exercise drastically decreased glutathione (GSH) content (∼79%) with concurrent decreased superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activities. However, these changes were attenuated in Rg1 group. Additionally, increased xanthine oxidase (XO) activity and nitric oxide (NO) levels after exercise were also inhibited by Rg1 pretreatment. For the first time, our findings provide strong evidence that ginsenoside-Rg1 can protect the liver against exhaustive exercise-induced oxidative damage
Oral Rg1 supplementation strengthens antioxidant defense system against exercise-induced oxidative stress in rat skeletal muscles
BACKGROUND: Previous studies reported divergent results on nutraceutical actions and free radical scavenging capability of ginseng extracts. Variations in ginsenoside profile of ginseng due to different soil and cultivating season may contribute to the inconsistency. To circumvent this drawback, we assessed the effect of major ginsenoside-Rg1 (Rg1) on skeletal muscle antioxidant defense system against exhaustive exercise-induced oxidative stress. METHODS: Forty weight-matched rats were evenly divided into control (N = 20) and Rg1 (N = 20) groups. Rg1 was orally administered at the dose of 0.1 mg/kg bodyweight per day for 10-week. After this long-term Rg1 administration, ten rats from each group performed an exhaustive swimming, and remaining rats considered as non-exercise control. Tibialis anterior (TA) muscles were surgically collected immediately after exercise along with non-exercise rats. RESULTS: Exhaustive exercise significantly (p<0.05) increased the lipid peroxidation of control group, as evidenced by elevated malondialdehyde (MDA) levels. The increased oxidative stress after exercise was also confirmed by decreased reduced glutathione to oxidized glutathione ratio (GSH/GSSG ratio) in control rats. However, these changes were completely eliminated in Rg1 group. Catalase (CAT) and glutathione peroxidase (GPx) activities were significantly (p<0.05) increased by Rg1 in non-exercise rats, while no significant change after exercise. Nevertheless, glutathione reductase (GR) and glutathione S-transferase (GST) activities were significantly increased after exercise in Rg1 group. CONCLUSIONS: This study provide compelling evidences that Rg1 supplementation can strengthen antioxidant defense system in skeletal muscle and completely attenuate the membrane lipid peroxidation induced by exhaustive exercise. Our findings suggest that Rg1 can use as a nutraceutical supplement to buffer the exhaustive exercise-induced oxidative stress
The Volcanic Earthquake Swarm of October 20, 2009 in the Tatun Area of Northern Taiwan
On October 20, 2009, a series of felt earthquakes with local magnitudes ranging from 2.8 - 3.2 occurred in the Tatun volcanic area off the northern tip of Taiwan. Although there was no damage caused by those earthquakes, many residents in the Taipei metropolitan area, particularly for people who live near the Yangminshan National Park, felt strong ground shaking. In order to know what the possible mechanisms were that generated those earthquakes, we carefully examined seismic data recorded by a dense seismic array in the Tatun volcanic area. During the period between October 18 and 22, 2009 we detected at least 202 micro-earthquakes. Most of the earthquakes were relocated using the double-difference method and were clustered in the shallow crust beneath the Dayoukeng area, which is the strongest fumarole in the Tatun volcanic area. Among these earthquakes, 72 focal mechanisms were determined by polarizing the first P-wave motion. Most earthquakes belonged to normal faulting. An extremely high b-value of 2.17 was obtained from those earthquakes. Based on the seismic variations in both the temporary and spatial distribution as well as an extremely high b-value, we conclude that the earthquake sequence on October 20, 2009 was a typically seismic swarm associated with possible active volcanism in the Tatun volcanic area
Initial Presentations Predict Mortality in Pulmonary Tuberculosis Patients - A Prospective Observational Study
Despite effective anti-TB treatments, tuberculosis remains a serious threat to public health and is associated with high mortality. Old age and multiple co-morbidities are known risk factors for death. The association of clinical presentations with mortality in pulmonary tuberculosis patients remains an issue of controversy.This prospective observational study enrolled newly diagnosed, culture-proven pulmonary tuberculosis patients from five medical centers and one regional hospital, which were referral hospitals of TB patients. Radiographic findings and clinical symptoms were determined at the time of diagnosis. Patients who died for any reason during the course of anti-TB treatment were defined as mortality cases and death that occurred within 30 days of initiating treatment was defined as early mortality. Clinical factors associated with overall mortality and early mortality were investigated.A total of 992 patients were enrolled and 195 (19.7%) died. Nearly one-third (62/195, 31.8%) of the deaths occurred before or within 30 days of treatment initiation. Older age (RR = 1.04, 95%CI: 1.03–1.05), malignancy (RR = 2.42, 95%CI: 1.77–3.31), renal insufficiency (RR = 1.77, 95%CI: 1.12–2.80), presence of chronic cough (RR = 0.63, 95%CI: 0.47–0.84), fever (RR = 1.45, 95%CI: 1.09–1.94), and anorexia (RR = 1.49, 95%CI: 1.07–2.06) were independently associated with overall mortality. Kaplan-Meier survival analysis demonstrated significantly higher mortality in patients present with fever (p<0.001), anorexia (p = 0.005), and without chronic cough (p<0.001). Among patients of mortality, those with respiratory symptoms of chronic cough (RR = 0.56, 95%CI: 0.33–0.98) and dyspnea (HR = 0.51, 95%CI: 0.27–0.98) were less likely to experience early mortality. The radiological features were comparable between survivors and non-survivors.In addition to demographic characteristics, clinical presentations including the presence of fever, anorexia, and the absence of chronic cough, were also independent predictors for on-treatment mortality in pulmonary tuberculosis patients
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