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Biomedical subjects

S Hu

Publications and source records attributed to S Hu.

427 records · Page 24Linked to original sources
PubMedDate not supplied

Acute hepatitis A infection in hepatitis B chimpanzee carriers.

Two hepatitis B virus carrier chimpanzees which were superinfected with hepatitis A virus developed acute hepatitis followed by the production of antibodies to hepatitis A virus. The Southern blot technique employed to monitor liver hepatitis B virus DNA revealed that the amount of viral DNA in both animals was significantly reduced during the acute phase of hepatitis A infection. The levels of plasma hepatitis B DNA polymerase activity were also reduced in one chimpanzee. The high titers of HBsAg in the circulation remained unchanged throughout the study, and antibodies to the surface antigen and to e antigen were not detected. The morphological lesions in the liver were severe in one chimpanzee from whom one specimen showed both periportal focal necrosis and zonal parenchymal necrosis.

Animals↗
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Cigarette smoking in a multiethnic population of youth: methods and baseline findings.

BACKGROUND: To expand upon recent research studies that have identified dramatic ethnic differences in adolescent cigarette smoking, this study was designed to characterize smoking among a multiethnic population of adolescents and to identify significant factors that may protect against smoking initiation. METHODS: During the first 2 years, this mixed cross-sectional, longitudinal study recruited and collected baseline data from a volunteer sample of 1,441 Houston-area public school students in the 5th, 8th, or 12th grade. A wide range of new and established predictors of smoking behavior was assessed, and their associations with ever smoking and susceptibility to smoking were assessed within ethnicity (white, N = 537; African-American, N = 454; and Hispanic, N = 297). RESULTS: Consistent with previous studies, white students smoked in substantially higher proportions than African-American students, with Hispanic adolescents in-between. Simultaneously adjusting for other variables, the odds of ever smoking (OR = 0.47, P < 0.01) and susceptibility to smoking (OR = 0.64, P < 0.01) were significantly lower among African-American adolescents when compared with whites; odds ratios for Hispanics and whites did not differ. Across all three ethnicities, the most important predictor of both ever smoking and susceptibility to smoking was the smoking status of the three best friends. Several ethnicity-specific variables also were identified. CONCLUSIONS: In concordance with previous investigations, cigarette smoking prevalence differs by ethnicity, and the factors associated with ever smoking and susceptibility to smoking differ among white, African-American, and Hispanic adolescents. The results of this study may be used to develop theory-based, culturally appropriate smoking intervention programs for adolescents.

Adolescent↗
PubMedDate not supplied

Transforming growth factor-beta protects human neurons against beta-amyloid-induced injury.

Deposition of amyloid fibrils in the brain is a histopathologic hallmark of Alzheimer disease (AD) and beta-amyloid protein (A beta), the principal component of amyloid fibrils, has been implicated in the neuropathogenesis of AD. In the present study, we first developed an in vitro model of A beta-induced neurodegeneration using human fetal brain-cell cultures and then tested the hypothesis that cytokines modulate A beta-induced neurodegeneration. When brain-cell cultures were exposed to A beta, marked neuronal loss (60% of neurons by microscopic assessment) and functional impairment (i.e., reduction in uptake of [3H]gamma-aminobutyric acid) were observed after 6 d of incubation. A beta-induced neurodegeneration was dose-dependent with maximal effect at 100 microM. Although interleukin (IL)-1, IL-6 and tumor necrosis factor (TNF)-alpha had a nominal effect, both the beta 1 and beta 2 isoforms of transforming growth factor-beta dose-dependently protected > 50% of neurons against A beta-induced injury. IL-4 also proved to be neuro-protective. A beta-induced neurodegeneration was accompanied by microglial cell proliferation and enhanced release of IL-1, IL-6, and TNF-alpha. These findings are consistent with the emerging concept that AD is an inflammatory disease and may lead to new therapeutic strategies aimed at reducing A beta-induced neurotoxicity.

Amyloid beta-Peptides↗
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Facial EMG as an indicator of palatability in humans.

Two experiments were conducted to observe the sensory hedonic responses and facial EMG activities elicited from different tastes. In Experiment 1, 25 subjects tasted flavors of apple juice, Gatorade, water, soybean milk, and pickle juice. In Experiment 2, 21 subjects tasted a sugar solution, a salt solution, and water. Subjects' sensory hedonic reports and facial EMG activity in the levator labii superioris/ alaeque nasi region were recorded in each experiment. The results from Experiment 1 showed that subjects reported significantly higher ratings of palatability to the apple juice, Gatorade, and water than to the soybean milk and pickle juice. The results from Experiment 2 indicated that the subjects reported significantly higher ratings of palatability to the water and sugar solution than to the salt solution. EMG recordings in both experiments showed that the negative hedonic sensations were associated with higher EMG activity in the levator labii muscle region, and that the positive hedonic sensations were associated with lower EMG activity in the same muscle region. It is concluded that facial EMG activity can be used as an indicator of palatability in humans.

Adolescent↗
PubMedDate not supplied

Cytokine-mediated neuronal apoptosis.

Cytokines have been reported to induce neuronal injury via the free radical nitric oxide (NO); however, the precise mechanism underlying cytokine-mediated neurotoxicity is unclear. We investigated the hypothesis that cytokine-mediated neurotoxicity in primary cultures of human fetal neurons occurs via an apoptotic mechanism triggered by NO. Treatment of mixed neuronal/glial cell cultures with interferon (IFN)-gamma plus interleukin (IL)-1 beta for 13 days induced a high output of NO accompanied by marked neuronal loss. The NO synthase inhibitor N-monomethyl-L-arginine (NMMA) significantly attenuated cytokine-induced neuronal loss, confirming the involvement of NO. Cytokine-mediated neuronal injury was accompanied by morphologic changes and a DNA fragmentation pattern consistent with apoptosis. Treatment of neuronal cell cultures with NMMA protected against cytokine-mediated apoptotic death. These findings, using primary human neuronal cell cultures, support the hypothesis that cytokine-mediated neurotoxicity involving NO proceeds via an apoptotic mechanism. These findings could lead to the development of new therapies for neurodegenerative diseases involving glia, cytokines, and NO.

Apoptosis↗
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Validation of the modified Fagerström tolerance questionnaire with salivary cotinine among adolescents.

This study was conducted to gain evidence of validity for a nicotine dependence measure for adolescent smokers. We hypothesized that the individual item responses and the total Fagerström Tolerance Questionnaire (FTQ) score would be positively correlated with cotinine values. We examined the relationship between a seven-item modified FTQ and saliva continine among 131 adolescent volunteers in a smoking cessation program. As anticipated, the total FTQ score was related to saliva cotinine (r = .40, p < .01), as were six of the seven individual FTQ items (p < .05). Our findings provide preliminary evidence that the modified FTQ scale is valid and applicable to adolescent smokers.

Adolescent↗
PubMedDate not supplied

[CT image analysis for surface reconstruction of the hip joint].

From a sequence of planar CT-pictures of the hip joint the diagnostically relevant contours are extracted on a graphic monitor by means of an image analysis process. To enable this an image-preprocessing has been needed to improve quality of the CT-pictures. From theses contour data, a mathematical surface model of the hip joint will be derived with well-known methods to simulate osteotomy.

Biomechanical Phenomena↗
PubMedDate not supplied

Asian hypersusceptibility to motion sickness.

A rotating optokinetic drum was used in three laboratory studies to test the hypothesis that Asian subjects are hypersusceptible to motion sickness. The results of the first study showed that Chinese women compared to European-American and African-American women experienced significantly more severe symptoms of motion sickness and greater disturbance of normal gastric myoelectric activity. A second study yielded similar results using American-born children of Asian parents. The results of a third study using Chinese men and women were similar and showed a significant increase in vasopressin during rotation. Possible genetic mechanisms that may account for these results are discussed.

Adolescent↗
PubMedDate not supplied

Special education in South Korea.

The development and current status of special education in South Korea are described and contrasted to that of the United States. South Korean special education was initiated in the 1890s by U.S. missionaries. Later, Japanese influence was considerable, especially on its regular educational programs. Special programs are available for five classifications of disabilities. Its major national special education legislation contains numerous provisions similar to P.L. 94-142. However, various conditions may impede the further development of services, including a high teacher-pupil ratio, the reliance on self-contained programs, negative attitudes toward people with disabilities, and lack of advocacy groups. Further initiatives require considerable research and policy debate among South Koreans.

Adolescent↗
PubMedDate not supplied

Human cytomegalovirus replication and modulation of apoptosis in astrocytes.

OBJECTIVES: To characterize replication patterns and cytopathic effects during human cytomegalovirus (HCMV) infection of brain cells. DESIGN: Primary human mixed glial/neuronal cells, as well as purified microglial, astroglial, and enriched neuronal cell cultures, were infected with HCMV strains AD169 and RC256 to determine the ability of the different brain cell types to support viral replication. RESULTS: Mixed glial/neuronal cell cultures were fully permissive for viral replication. Based on previous studies, we hypothesized that human microglial cells would preferentially support productive HCMV replication. However, HCMV did not replicate or display genomic expression in microglial cells. In contrast, primary astrocytes were fully permissive and displayed HCMV-induced cytopathic effects resulting in cell death. In highly enriched neuronal cultures, productive infection and viral expression occurred only in scattered astrocytes. Early in the infection, apoptotic plasma membrane changes were induced in astrocytes. However, nuclear fragmentation was not apparent until later during the course of infection. CONCLUSIONS: These results suggest that HCMV possesses astrocytotropic properties that confer preferential expression and cytopathic replication in astrocytes over microglia or neuronal cells. Apoptotic cell death, which is a result of HCMV infection, appears to be delayed until peak viral replication has occurred.

Antigens, Viral↗
PubMedDate not supplied

Evaluation of the clinical value of combination of 99mTc-MIBI myocardial SPECT and 18F-FDG PET in assessing myocardial viability.

PURPOSE: To evaluate the value of 18F-FDG PET metabolic imaging and 99mTc-MIBI SPECT in the identification of myocardial viability in patients with previous myocardial infarction and left ventricular dysfunction. METHODS: 18F-FDG PET (made in China) and 99mTc-MIBI SPECT were performed in 60 patients (pts) (age 54+/-9 yr) with myocardial infarction before revascularization. Before and after revascularization, LVEF and wall motion were measured with echocardiography in 36 pts (Group A), and myocardial perfusion was evaluated in 24 pts (Group B). RESULTS: According to the interpretation of perfusion and metabolic images, myocardial segments were classified into mismatch (MM): reduced myocardial perfusion and normal FDG uptake or match (M): reduced perfusion and FDG uptake. Out of 264 segments with hypoperfusion, 145 (54.9%) were MM, suggesting viable myocardium (G-A1 and G-B1), 119 (45.1%) were M, suggesting necrosis (G-A2 and G-B2). After revascularization, LVEF was increased in G-A1 (49+/-15% vs. 59+/-7%, p<0.05), and in G-B1 (50+/-8% vs. 59+/-12%, p<0.05), but was not improved in G-A2 and G-B2. LVEDD was decreased in G-A1 and G-B1 (p<0.05) and was unchanged in G-A2 and G-B2. The positive predictive value (PPV) of FDG PET for improvement of regional wall motion after revascularization was 88%, and the negative predictive value (NPV) was 72.6%. The PPV for improvement of perfusion was 84.1%, NPV was 85%, and accuracy was 84.4%. CONCLUSION: 18F-FDG imaging with Chinese PET has clinical value for assessing myocardial viability and identifying patients who will benefit from revascularization.

Evaluation Studies as Topic↗
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A multivariate analysis of the relationship between work ability and S. japonicum infection in Dongting Lake region, in China.

A cross-sectional case-control study on the association between the reduced work ability and S. japonicum infection was carried out in a moderate endemic area for schistosomiasis japonica in the southern part of Dongting lake in China. A total of 120 cases with reduced work ability and 240 controls paired to the case by age, sex, occupation and without reduced work ability, participated in the study. The mean age for individuals was 37.6 years old (21-60), the ratio of male:female was 60:40, the prevalence of S. japonicum in the individuals was 28.3%. The results obtained in this study showed that the infection of S. japonicum in case and control groups was 49.2% (59/120) and 17.9% (43/240), respectively. Odds ratio for reduced work ability among those who had schistosomiasis was 4.34 (95%), confidence interval was 2.58-7.34, and among those who had S. japonicum infection (egg per gram > 100) was up to 12.67 (95%), confidence interval was 3.64-46.39. After odds ratio was adjusted by multiple logistic regression, it was confirmed that heavier intensity of S. japonicum infection and splenomegaly due to S. japonicum infection were the main risk factors for reduced work ability in the population studied.

Adult↗