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Biomedical subjects

S Hu

Publications and source records attributed to S Hu.

At least 307 records · Page 17Linked to original sources
PubMed1995

Morphine stimulates phagocytosis of Mycobacterium tuberculosis by human microglial cells: involvement of a G protein-coupled opiate receptor.

Opiate-induced immunosuppression has been implicated in the pathogenesis of infections caused by a variety of microorganisms, including human immunodeficiency virus (HIV). Although effects of opiates on lymphocyte function have been studied more extensively, morphine also has been shown to inhibit several functional activities of mononuclear phagocytes (e.g. chemotaxis, respiratory burst activity and phagocytosis). Opiate addiction has been identified as a risk factor for clinical tuberculosis prior to the HIV epidemic, and macrophages are a key cell in the pathogenesis of Mycobacterium tuberculosis. Thus, the hypothesis was tested in the present study that morphine would suppress phagocytosis of M. tuberculosis by human microglial cells, the resident macrophages of the brain. Contrary to this hypothesis, treatment of human fetal microglial cell cultures with morphine (10(-8) M) was found to stimulate phagocytosis of nonopsonized M. tuberculosis H37Rv. The stimulatory effect of morphine was blocked by naloxone and the mu opiate receptor selective antagonist beta-funaltrexamine. Also, morphine-induced increase in phagocytic activity was markedly inhibited by pertussis toxin and was unaffected by cholera toxin, suggesting the mechanism of morphine's stimulatory effect on microglial cell phagocytosis involves a Gi protein-coupled mu opiate receptor. The results of this in vitro study support the concept that exogenous and endogenous opioids play an immunomodulatory role within the central nervous system through their interaction with G protein-coupled receptors on microglial cells.

Adjuvants, Immunologic↗
PubMed1995

Correlative transmission and scanning electron microscopy study of microglia activated by interferon-gamma and tumor necrosis factor-alpha in vitro.

Microglia, in response to cytokines, demonstrate a number of enhanced biochemical and functional properties which reflect a state of activation. In this study, we evaluated the ultrastructural alterations of murine microglia that were associated with activation by interferon-gamma (IFN-gamma) plus tumor necrosis factor-alpha (TNF-alpha). Microglial cell culture treated with these cytokines generated significant amounts of the free radical nitric oxide (NO), a biochemical marker of activation. Correlative transmission (TEM) and scanning (SEM) electron microscopic analyses of these cytokine-activated microglia demonstrated two prominent features: proliferation of cell processes and increased formation of membrane bound dense bodies typical of lysosomes. Since activated microglia have been implicated in the pathogenesis of a number of neurodegenerative diseases, application of the ultrastructural findings in the in vitro study may prove useful in determining the state of activation of microglia in brain specimens from patients with these neurological disorders.

Animals↗
PubMed1995

Linkage between sexual orientation and chromosome Xq28 in males but not in females.

We have extended our analysis of the role of the long arm of the X chromosome (Xq28) in sexual orientation by DNA linkage analyses of two newly ascertained series of families that contained either two gay brothers or two lesbian sisters as well as heterosexual siblings. Linkage between the Xq28 markers and sexual orientation was detected for the gay male families but not for the lesbian families or for families that failed to meet defined inclusion criteria for the study of sex-linked sexual orientation. Our results corroborate the previously reported linkage between Xq28 and male homosexuality in selected kinships and suggest that this region contains a locus that influences individual variations in sexual orientation in men but not in women.

Base Sequence↗
PubMed1995

Thalidomide inhibits tumor necrosis factor-alpha production by lipopolysaccharide- and lipoarabinomannan-stimulated human microglial cells.

Tumor necrosis factor-alpha (TNF-alpha) is a pathogenic factor in bacterial meningitis. The effect of thalidomide on TNF-alpha production by microglia, the resident macrophages of the brain, was evaluated. In primary human fetal microglial cell cultures stimulated with lipopolysaccharide or lipoarabinomannan, thalidomide inhibited TNF-alpha release in a dose-dependent manner. The inhibitory effect of thalidomide was similar to that of dexamethasone, although expression of TNF-alpha mRNA in microglial cells was reduced only by thalidomide. The results of this in vitro study suggest that thalidomide could have therapeutic potential in gram-negative bacterial and tuberculous meningitis.

Base Sequence↗
PubMed1995

Mouse macrophage metalloelastase expressed in bacteria absolutely requires zinc for activity.

Mouse macrophage metalloelastase was expressed in Escherichia coli. This recombinant enzyme (rMME) was present in the inclusion bodies that were solubilized in 7 M guanidine HCl. After removal of guanidine HCl, rMME was purified with a Q-Sepharose column. Degradation of [3H]elastin by rMME absolutely required Ca2+; the optimal Ca2+ concentration was 5 mM. NaCl stimulated the enzyme activity; maximal stimulation was obtained at 400 mM. The rMME activity was inhibited by metalloprotease inhibitors, but not by serine, aspartyl, or thiol protease inhibitors. Among the divalent cations tested, only Ba2+ and Sr2+ exhibited marginal stimulation of rMME activity in the absence of Ca2+. Cu2+, Zn2+, or Cd2+ strongly inhibited rMME activity with IC50 values between 68 and 180 microM, while Mg2+, Ba2+, Mn2+, Co2+, and Sr2+ had no effect. The requirement of Zn2+ for rMME activity was determined. Significant enzyme activity was present in rMME treated with EDTA followed by Q-Sepharose column chromatography. Only when the inclusion bodies were solubilized in the presence of 20 mM EDTA, did an enzyme preparation which was absolutely dependent on exogenous Zn2+ for activity result. The optimal Zn2+ concentration for rMME activation was 100 microM. These results indicate that Zn2+ is tightly bound to rMME.

Amino Acid Sequence↗
PubMed1995

Tumor necrosis factor alpha upregulates human microglial cell production of interleukin-10 in vitro.

Interleukin (IL)-10 appears to play an important regulatory role in the systemic inflammatory response; however, production of IL-10 within the human central nervous system has not been described. Using cultures of human fetal microglial cells, the resident macrophages of the brain, we investigated the production and regulation of bioactive IL-10. Lipopolysaccharide stimulated acute release of tumor necrosis factor (TNF)-alpha (peak by 8 h) and delayed production of IL-10 (over a 48-h period) in microglial cell cultures. Treatment of microglial cell cultures with TNF-alpha and IL-6 resulted in a dose-dependent release of IL-10. These cytokines also induced expression of IL-10 mRNA. Treatment of microglial cell cultures with IL-10 markedly inhibited TNF-alpha and IL-6 production. These findings suggest that during inflammation within the brain, acute release of TNF-alpha and IL-6 by activated microglia could promote subsequent release of IL-10, which functions to minimize the potential neurotoxic effects of proinflammatory cytokines.

Base Sequence↗
PubMed1995

CD14 receptor-mediated uptake of nonopsonized Mycobacterium tuberculosis by human microglia.

This study was carried out to determine the role of CD14 receptors in the uptake of nonopsonized Mycobacterium tuberculosis by human microglia. Treatment of microglial cell cultures with antibodies to CD14 or with soluble CD14 significantly blocked infection by M. tuberculosis H37Rv, suggesting that CD14 receptors could facilitate entry of nonopsonized tubercle bacilli into macrophages within the brain.

Antigens, CD↗
PubMed1995

Tumor necrosis factor-alpha production by human fetal microglial cells: regulation by other cytokines.

Tumor necrosis factor (TNF)-alpha has been postulated to play an important physiologic as well as pathologic role within the developing brain. In the present study, we found that human fetal microglial cells released abundant amounts of TNF-alpha upon stimulation with lipopolysaccharide (LPS). Treatment of microglial cell cultures with antibodies specific to interleukin (IL)-6, IL-10, and transforming growth factor (TGF)-beta augmented LPS-stimulated release of TNF-alpha. Each of these cytokines dose-dependently suppressed TNF-alpha release. Also, TNF-alpha mRNA expression was inhibited by each of these cytokines. By way of contrast, treatment of microglial cell cultures with IL-alpha or IL-1 beta alone or in the presence of LPS, resulted in increased release of TNF-alpha, and IL-1 stimulated the expression of TNF-alpha mRNA. These findings suggest that these cytokines are likely to modify the beneficial and harmful effects of TNF-alpha within the developing brain.

Base Sequence↗
PubMed1995

Effects of positive attitude toward giving a speech on cardiovascular and subjective fear responses during speech in anxious subjects.

40 speech-anxious subjects were asked to deliver four speeches during the experiment. The conditions varied according to whether the subjects maintained a positive or neutral attitude toward speech prior to each presentation. Heart rate and self-reports of fear were measured during the experiment. Maintaining a positive attitude prior to delivering a speech reduced both subjective anxiety and cardiovascular responses.

Anxiety↗
PubMed1995

[Correlation of fetal umbilical artery velocity waveforms with placental pathology and biochemistry].

The ratio of peak systolic to least diastolic flow velocity (S/D) of the umbilical artery was measured in 119 pregnant women and its relation with placental pathology were studied. Results obtained indicated that S/D ratio decreased gradually with advanced gestational age and showed a negative correlation (r = -0.972 8, P < 0.01). A ratio of < 3 was defined as normal value. Patients were divided into 2 groups according to the S/D ratio and their placental histological findings were compared. The number of small arteries in the tertiary villi stem and syncytial vascular membranes were significantly less in group 2 (S/D > or = 3) than that in group 1 (S/D < 3, P < 0.01). The counts of villous syncytial knots and stroma fibrosis of villi were more significant in the placenta of group 2 as well. The mean value of molondialdehyde in placenta of group 2 was significantly higher (P < 0.01) than that of group 1, while superoxide dismutase value is to the contrary (P < 0.01). These indicated that there was a reduced circulation resistance in placenta during normal pregnancy and remained stable till term. When S/D > or = 3, it indicated that physiological and biochemical changes occurred in placenta and the outcome of pregnancy might be affected.

Blood Flow Velocity↗
PubMed1995

P6 acupressure reduces symptoms of vection-induced motion sickness.

PURPOSE: The purpose of the study was to examine the effectiveness of P6 acupressure on nausea associated with visually-induced motion sickness. METHOD: There were 64 subjects randomly divided into 4 groups: P6 acupressure, dummy-point acupressure, sham P6 acupressure, and control. Each subject sat in an optokinetic drum for a 12-min baseline and 12-min drum rotation period. Subjects' electrogastrograms (EGG's) and subjective symptoms of motion sickness were obtained. RESULTS: The results indicated that the subjects in the P6 acupressure group reported significantly less nausea [F(3,60) = 8.16, p < 0.0001] during drum rotation period than those in the dummy-point acupressure, sham acupressure, and control groups. The scores for symptoms of motion sickness of the P6 acupressure group were significantly lower than those in the sham acupressure and control groups [F(3,60) = 3.49, p < 0.02]. Also, the subjects in the P6 acupressure group showed significantly less abnormal gastric myoelectric activity, tachyarrhythmia, than those in the sham acupressure and control groups [F(3,60) = 2.78, p < 0.04]. However, the subjects in the dummy-point acupressure group did not report significantly fewer symptoms and show less tachyarrhythmia than those in the sham acupressure and control groups. CONCLUSION: We conclude that P6 acupressure reduces the severity of symptoms of visually-induced motion sickness and gastric tachyarrhythmia.

Acupuncture Points↗
PubMed1995

Detection of human papillomavirus types 16, 18 DNA related sequences in bronchogenic carcinoma by polymerase chain reaction.

In studying the relationship between human papillomavirus (HPV) and bronchogenic carcinoma, "high-risk" HPV 16, 18 DNA sequences were detected in samples from 50 lung cancer patients, 18 patients with benign pulmonary diseases and 4 fetal lung tissues by polymerase chain reaction (PCR) and dot-blot hybridization with biotin-labelled probes. The results showed that HPV 16, 18 DNA related sequences were found in 32% of lung cancer specimens, with 10 cases of HPV 16, 5 cases of HPV 18 and 1 case of both types. 48.15% (13/27) of squamous cell carcinomas were shown to be positive for HPV 16, 18 DNA. In addition, two adenocarcinomas and one small cell carcinoma were positive for HPV 16 DNA. No specimens from benign diseases tissues and fetal lung tissues showed positive results. These results suggest that primary bronchogenic carcinoma is related to HPV infection.

Adenocarcinoma↗
PubMed1995

[A study on recovery of recurrent laryngeal nerve defect by degenerative skeletal muscle bridge with vascular implantation].

The dog's recurrent laryngeal nerve defect (1cm) was repaired by near vessels implantation of heat denaturation muscles as a bridge. Three months after operation, regenerative nerve neurite smoothly passed through muscle bridge, grew into distal isogenous nerves and formed function joint. The implanted vessels grew and branched in the muscle bridge. Six months later, the motor end plates of caryngeal muscle grew well, laryngeal electromyography showed that nerves contraction of laryngeal muscles built. Laryngoscopy showed that vocal cord moved to the normal position. The voice perfectly recovered.

Animals↗
PubMed1995

Ginseng-enhanced oxidative and phagocytic activities of polymorphonuclear leucocytes from bovine peripheral blood and stripping milk.

This study investigated the effect of a dried ginseng extract on polymorphonuclear leucocytes (PMNL) in bovine blood and milk. In a test for chemiluminescence (CL), PMNL were pre-incubated in ginseng solution at 37 degrees C in 5% CO2 for 60 min, and then stimulated with bovine serum opsonized zymosan. The CL was about 30% higher for the cells pre-treated with ginseng solutions 100-1,000 micrograms/ml as compared with the non-ginseng-treated cells. In a test for phagocytosis, PMNL and fluorescent microspheres were incubated with ginseng in RPMI-1640 supplemented with 10% bovine serum at 37 degrees C for 60 min. The proportion of actively phagocytic cells in the ginseng-treated group was greater than that in the non-ginseng treated group.

Animals↗
PubMed1995

[Determination of oleanolic acid in the root of Achyranthes bidentata Bl. from different places of production by TLC-scanning].

The contents of oleanolic acid in the root of Achyranthes bidentata and A. aspera from different places of production have been determined by dual-wavelength TLC-scanning. The results show that the content of oleanolic acid is 0.91%-1.14% in cultured A. bidentata, 0.78%-1.42% in A. bidentata natural and 0.054% in A. aspera. The average recovery is 98.63%.

Chromatography, Thin Layer↗
PubMed1995

Community level cancer control in a Texas barrio: Part II--Base-line and preliminary outcome findings.

In a quasiexperimental demonstration study, screening rates for breast and cervical cancers were measured among Mexican-American women in selected areas of San Antonio and Houston, Tex. This research was primarily designed to evaluate a cancer-screening promotion program in San Antonio by comparing changes in screening rates in panels from the two barrio communities. In a base-line population survey, we found a small, but significant, proportion of women (10%-15%) lacking Pap smears and a larger proportion (30%-40%) lacking mammography. In a panel study following women who lacked screening at base line, there was a trend toward greater Pap smear use among younger women and a significant increase in mammography for all age groups in San Antonio compared with groups in Houston. Although there was a difference in language use between the communities, rates of newly initiated screening within the communities were similar among monolingual Spanish speakers and among those who used English, supporting the hypothesis that the program increased both groups' participation in breast-cancer screening.

Adult↗
PubMed1995

Glia, cytokines, and neurotoxicity.

Activated glial cells (microglia and astrocytes) are a hallmark of several neurodegenerative disorders. A growing body of evidence supports the hypothesis that activation of glial cells by cytokines contributes to neurotoxicity. Although the precise mechanisms underlying glia-mediated neurotoxicity are unclear, it has been proposed that the generation of toxic free radicals or other neurotoxins is involved. This review focuses on the role of immune mediators released by activated glial cells in causing or preventing neuronal injury. Also, techniques used to assess neurotoxicity are discussed. It is hoped that research in this field will yield insights that will result in new therapies for neurodegenerative disorders.

Cytokines↗