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Biomedical subjects

S Hu

Publications and source records attributed to S Hu.

At least 271 records · Page 15Linked to original sources
PubMed1996

Cytokine-stimulated astrocytes damage human neurons via a nitric oxide mechanism.

Astrocytes have been reported to play a neuropathogenic role within the brain, although little is known about the mechanism underlying astrocyte-mediated neuronal injury. We investigated the hypothesis that cytokine-stimulated astrocytes adversely affect neuronal cell survival via generation of the free radical nitric oxide (NO). Primary human astrocytes produced substantial amounts of NO in response to interleukin (IL)-1 alpha or IL-1 beta, which was blocked by the NO synthase inhibitor NG-mono-methyl-L-arginine (NMMA). IL-1 beta-induced NO production was markedly potentiated by interferon (IFN)-gamma. IL-1 receptor agonist protein (IRAP) totally blocked NO generation by cytokine-stimulated astrocytes. Using reverse transcription-polymerase chain reaction and sequencing analyses of the astrocyte NO synthase gene, we found a single band encoding for a 615 bp product that was identical to the corresponding sequence reported for human hepatocytes. Treatment of human fetal brain cell cultures with IL-1 beta plus IFN-gamma resulted in marked neuronal loss, as assessed by microscopic analysis and measurement of lactate dehydrogenase release. This cytokine-induced neuronal damage was blocked by simultaneous treatment of the brain cell cultures with NMMA or IRAP, suggesting a critical role of IL-1. These findings indicate that cytokine-stimulated astrocytes are neurotoxic via a NO-mediated mechanism and point to potential new therapies for neurodegenerative disorders that involve cytokines and reactive astrocytes.

Astrocytes↗
PubMed1996

Cytokine and free radical production by porcine microglia.

Swine have been used increasingly as an animal model for a variety of immunologic purposes. Because the functional activities of porcine microglia, the resident macrophages of the brain, have not been elucidated, highly enriched porcine microglial cell cultures were developed in the present study to assess cytokine and free radical production by these cells compared to microglia of human and murine origin. Porcine microglial cells were found to behave similarly to both human and murine cells in releasing tumor necrosis factor-alpha and interleukin-1 and in generating superoxide anion. In contrast to murine cells, porcine microglial cells, like human cells, failed to generate NO in response to cytokine stimulation. These findings suggest that swine will serve as an excellent model for investigations of central nervous system diseases in which microglia are involved in host defense or neuronal injury.

Animals↗
PubMed1996

Susceptibility to immunologically mediated fatigue in C57BL/6 versus Balb/c mice.

Proinflammatory cytokines such as interleukin (IL)-1 and tumor necrosis factor (TNF)-alpha have been proposed to play a role in the pathogenesis of fatigue. In the present study we compared the susceptibility of two mouse strains to immunologically induced fatigue. Daily running of two strains of mice, Balb/c and C57BL/ 6, was assessed after a single injection of Corynebacterium parvum antigen (2 mg/mouse). Spontaneous running activity of each animal was compared to mean running distance prior to injection. To evaluate the involvement of cytokines in fatigue development, C57BL/6 mice were treated with antibodies to specific cytokines at the time of challenge with C. parvum antigen. Also, cytokine mRNA expression was analyzed in the brains of mice at different time periods after immunologic challenge. A significant difference in running activity between the two mice strains was observed after C. parvum antigen inoculation: C57BL/6 mice showing a greater (P < 0.05) reduction in running activity (relative to preinjection levels) and slower recovery to baseline than Balb/c mice. Injection of antibodies specific to either IL-1beta or TNF-alpha did not alter immunologically induced fatigue, suggesting a lack of involvement of these cytokines produced outside of the central nervous system (CNS). However, increased TNF-alpha and IL-1beta mRNA expression was found in the brains of C57BL/6 compared to that seen in Balb/c mice at 6, 10, and 15 days after C. parvum antigen injection. The elevated CNS cytokine mRNA expression corresponded to development of fatigue. These findings are consistent with the hypothesis that expression of proinflammatory cytokines within the CNS plays a role in the pathogenesis of immunologically mediated fatigue.

Animals↗
PubMed1996

Is community financing necessary and feasible for rural China?

The collapse of the Cooperative Medical System (CMS) in China after the agricultural reforms of the early 1980s caused serious concern and doubt about the viability of community financing of basic health care for the low-income population. This paper examines the rise and fall of China's community financing schemes and ascertains the need for and feasibility of community financing. Of the Chinese rural population, 90% now pay out-of-pocket for their health services. Both the problems with the fee-for-service system on the one hand and the observed advantages of the existing community financing schemes on the other indicate the necessity and desirability of revitalizing community financing as a major rural health care reform strategy. However, the feasibility of the community financing approach depends on adequate financial and social resources. Our study found that there are multiple potential funding sources for health care in rural areas, including households, village welfare funds, local enterprises, and the government. We designed several illustrative benefit packages and estimated their costs. It appears that a basic benefit package with high co-insurance would be affordable if funds could be mobilized from multiple sources. More importantly, community financing would require governmental promotion and support.

China↗
PubMed1996

Multinucleated giant cell formation of swine microglia induced by Mycobacterium bovis.

Multinucleated giant cells (MGC) have been long recognized as a histopathologic feature of tuberculosis, yet little is known about the underlying mechanism of tubercle bacillus-induced formation of these fused macrophages. The main purpose of this study was to characterize cellular mechanisms involved in MGC formation of swine microglia, the resident macrophages of the brain, in cultures containing nonopsonized Mycobacterium bovis. Within 2 h of incubation, MGC were readily detected in these cultures by light and transmission electron microscopy. MGC formation was blocked by anti-CD14 and anti-CD18 antibodies and by thalidomide, a potent inhibitor of tumor necrosis factor-alpha (TNF-alpha) production my microglia. Also, TNF-alpha alone induced MGC formation. These findings suggest that two microglial cell receptors, CD14 and a beta2 integrin, and the cytokine TNF-alpha participate in M. bovis-induced swine microglial MGC formation.

Animals↗
PubMed1996

Optokinetic rotation-induced taste aversions correlate with over-all symptoms of motion sickness in humans.

51 subjects were divided into Familiar- and Unfamiliar-drink groups based on whether they had tasted soybean milk before the experiment. Each subject then viewed an optokinetic rotating drum for 10 min. Subjective assessments of nausea and over-all symptoms of motion sickness were measured during the drum rotation. Two hours later subjects drank the soybean milk again. The consumed volume and rating of likeableness of the drink were subsequently measured. Analysis showed that the subjects in the Unfamiliar-drink group reported significantly higher taste aversion and consumed significantly less soybean milk after rotation than those in the Familiar-drink group. Correlation for the Unfamiliar-drink group indicated that the rated taste aversion was positively correlated with ratings of over-all symptoms of motion sickness and that the consumed volume of soybean milk was negatively correlated with ratings of over-all symptoms of motion sickness. We concluded that the magnitude of acquired conditioned taste aversion was dependent upon the severity of over-all symptoms of visually induced motion sickness when subjects were unfamiliar with the flavor of the target drink.

Adolescent↗
PubMed1996

Glia: the not so innocent bystanders.

Activated glial cells (microglia and astrocytes) are a hallmark of a variety of neurodegenerative diseases. Recent in vitro studies have suggested that mediators derived from reactive glial cells (eg, cytokines, reactive oxygen intermediates, nitric oxide, glutamate or quinolinic acids, and neurotoxins) contribute to neuronal injury. Several of these mediators have been implicated in the neuropathogenesis of HIV-1. Although the precise role of glial cell-mediated neurotoxicity in viral infections of the central nervous system has not been established, it is hoped that research in this field will yield new therapies for these infections as well as for immune-mediated neurodegenerative diseases.

Nervous System Diseases↗
PubMed1996

The proliferative responses of cow stripping milk and blood lymphocytes to pokeweed mitogen and ginseng in vitro.

Milk samples were collected directly after the morning milking (stripping milk) from eight cows of the Swedish Red and White breed, during the period of mid-lactation. The milk cells (29 +/- 11 x 10(6)) were obtained after centrifugation and by passing the cell pellet through a cotton column. They consisted of 36 +/- 9% lymphocytes, 14 +/- 2% macrophages and 50 +/- 10% polymorphonuclear leukocytes. The autologous peripheral blood lymphocytes were separated by means of a Ficoll-gradient. The lymphocytes from the blood and milk were subjected to the lymphocyte stimulation test (LST). The stimulation indices (SI) demonstrated that pokeweed mitogen (PWM) induced a greater degree of proliferation in the autologous peripheral blood lymphocytes than it did in the stripping milk lymphocytes (39 +/- 8 vs 5 +/- 1, respectively, P < 0.01). Ginseng (GS), the root of Panax ginseng CA Meyer, has been used in China for thousands of years to enhance the body's resistance to many diseases. In the present study, a dry ginseng extract was investigated to evaluate its immunomodulating effects in vitro on the peripheral blood and stripping milk lymphocytes. The response was significantly augmented (approximately 20%) in the peripheral blood lymphocytes incubated with GS extract in combination with PWM, as compared with the cells incubated with PWM alone. Increased responses were also detected with the lymphocytes from stripping milk incubated with GS+PWM, but to a much lesser extent (approximately 9%) compared with the autologous peripheral blood lymphocytes.

Animals↗
PubMed1996

Motion sickness susceptibility to optokinetic rotation correlates to past history of motion sickness.

PURPOSE: This study investigated correlations between motion sickness susceptibility to a rotating optokinetic drum and past history of motion sickness. METHOD: There were 49 subjects who filled out a questionnaire on motion sickness history (MSH) who participated in the experiment. Each subject sat in an optokinetic drum for a 12-min baseline and a 12-min drum rotation period. Subjects' motion sickness symptoms (MSS) and electrogastrograms (EGG's) were measured. RESULTS: There were significant correlations between MSH scores and MSS scores during drum rotation (r = 0.5392, p < 0.001), and between MSH scores and EGG 4-9 cycles per minute (cpm) spectral intensity ratios between drum rotation and baseline periods (r = 0.5320, p < 0.001). Further analysis indicated that the mean MSS scores during the drum rotation period were 11.50 for the top 33% MSH scorers, 4.18 for the middle 34% MSH scorers, and 3.63 for the bottom 33% MSH scorers. The mean EGG 4-9 cpm spectral intensity ratios between drum rotation and baseline periods were 2.62 for the top 33% MSH scorers, 1.44 for the middle 34% MSH scorers, and 1.21 for the bottom 33% MSH scorers. CONCLUSION: These results indicated that past history of motion sickness correlates with severity of motion sickness provoked by optokinetic rotation.

Adult↗
PubMed1996

[Textual studies on shangzhou zhiqiao fructus Aurantii].

The original plant of Shangzhou Zhiqiao, the best among the species of Zhiqino, is confirmed as Citrus aurantium rather than Poncirus trifolia in this paper based on the description and drawings of Zhiqiao in (Bencao Gangmu) by Li Shizhen in the 16th rentury, samples from Shangzhou(Shanxi Province), and the cold-warm period of historical climate in the local area, which is believed to be related to the distribution of C. aurantium in Shangzhou. However, P.trifolia has often been confused with C. aurantium by some herbalists.

Citrus↗
PubMed1996

[The influence of surfactant on the alveolar morphology in premature rabbits].

OBJECTIVE: To study the effects of treatment by surfactant manufactured by our institute on premature rabbits through observation of alveolar morphologic changes. METHODS: The morphology of alveolar area in the premature rabbits were quantitatively studied by morphometry. RESULTS: In the surfactant treated group, there was a reduction of alveolar number, and increases in alveolus area and the ratio of alveolus to alveolar septum. These changes were better than that in the control group. CONCLUSION: Our surfactant was effective for respiratory distress syndrome in premature rabbits.

Animals↗
PubMed1996

[Effect of acupuncture on the restrained state of stomach after injecting TFP in zusanli point].

A model of the reducible movement of stomach in a big mouse was set up by injecting solution of 654-2. At first, the state of stomach movement was proved to be improved by acupuncture. After that, the activity of CaM in Zusanli point was lost by injecting TFP and effect of acupuncture on the stomach movement was studied. The result showed that the effect of acupuncture was abolished during manipulating the needles for 5 minutes. But retaining the needle for 25 minutes, the effect of acupuncture was recovered gradually. It indicates that the activity of Ca-CaM compounds may be of the key factor of acupuncture effect and one of the important links of the functional activity of meridians and collaterals.

Acupuncture Points↗
PubMed1996

[Late result of valve replacement with giant heart].

212 cases of valve replacement with giant heart were followed up for 0.2-15.7 years (mean 3.23 years). There were 21 late deaths. The total survival rate was 91.3%, 80.6%, 74.3% at the 3rd, 6th and 9th year after operation, respectively, and the symptomatic remission rate was 84.4%, 70.6%, 56.8%, respectively. In patients with left atrium and right cardiac enlargement, the survival rate and symptomatic remission rate was significantly higher than those of left ventricle and total cardiac enlargement. The factors influencing late surgical result was discussed.

Adolescent↗
PubMed1996

[A pathological study of goat multiple organ failure model].

We succeeded in replication a standardized goat model of multiple organ failure (MOF). In the experimentation, the animals were monitored and supported with facilities pertaining to a human intensive care unit, with constant infusion of LPS into portal vein following trauma and hemorrhagic shock. The main organs of MOF goats were observated by the light microscopy and electronmicroscopy, including the lungs, hearts, livers, kidneys, intestines and spleens. The results showed that there were some areas of spotty and mass necrosis in the organ parenchyma with inflammatory cell infiltration. Our studies suggested that once the clinical multiple organ failure, severe pathological changs occur in organs.

Animals↗