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Biomedical subjects

H He

Publications and source records attributed to H He.

At least 163 records · Page 9Linked to original sources
PubMed1998

Violence and HIV sexual risk behaviors among female sex partners of male drug users.

OBJECTIVE: Violence and HIV are emerging as interconnected public health hazards among drug users and their families. The purposes of this study are to (1) determine the prevalence of sexual and physical abuse of non-drug-using female sex partners of male drug users, and (2) ascertain the association between such violence and HIV-related risk behaviors. METHODS: From 11/93 to 11/95, 208 female sex partners of injection drug or crack users in Collier County, FL, Tucson, AZ, and Portland, OR, were interviewed as part of a NIDA-funded HIV risk reduction project. Their mean age was 30 years (range 18-54); 21% were White, 6% African American, 7% Native American, and 63% Hispanic. RESULTS: Of the 208 women, 28% reported being sexually molested and 20% raped before age 13; 41% reported being raped at least once in their lifetime. Forty-two percent of the women were physically assaulted by their sex partners; 36% had been threatened with assaulted by their sex partners. Those who were raped or threatened with assault were more likely to have multiple sex partners and engage in unprotected anal sex; there was a trend for women who had been physically assaulted to be more likely to engage in unprotected anal sex. DISCUSSION: Rape, assault and the threat of assault are commonplace in the histories of female sex partners of male drug users. Experiences of violence and threats of violence are associated with heightened risk for the sexual transmission of HIV. Providers of HIV prevention need to understand the sequelae of violence, and design interventions which empower women to protect themselves from sexual transmission of HIV.

Adult↗
PubMed1998

Presence of antibodies to heat stress proteins in workers exposed to benzene and in patients with benzene poisoning.

Heat shock or stress proteins (Hsps) are a group of proteins induced by a large number of xenobiotics, many of which are common in the working and living environment. The biological significance of the presence of antibodies against Hsps in humans is presently unknown. In the present study, 112 workers were selected and divided into four groups on the basis of their level of occupational exposure to benzene: a control group, two groups of workers exposed to either low (< 300 mg/m3) or high concentrations of benzene (> 300 mg/m3) and a group of workers who had experienced benzene poisoning. Blood samples from these workers were assayed for the number of peripheral white blood cells, concentration of hemoglobin, activities of serum superoxide dismutase (SOD), lymphocyte DNA damage and finally for the presence of antibodies to different human heat-shock proteins (Hsp27, Hsp60, Hsp71 and Hsp90). Benzene-poisoned workers showed a high incidence of antibodies against Hsp71 (approximately 40%) which was associated with a decrease in white blood cells (3.84+/-1.13 x 10(9)versus 7.68+/-1.84 x 10(9) in controls) and with an increase in activities of serum SOD (138.43+/-23.15 micro/ml) and lymphocyte DNA damage (18.7%). These data suggest that antibodies against Hsps can potentially be useful biomonitors to assess if workers are experiencing or have experienced abnormal xenobiotic-induced stress within their living and working environment.

Adult↗
PubMed1998

[Autologous endothelial cell transplantation in meacacos].

OBJECTIVE: To lay a theoretical foundation for the clinical application of autologous endothelial cell transplantation. METHODS: Macaco endothelial cells derived from superficial veins were cultivated in vitro for 13.89 +/- 1.36 days. The multiplied cells were lined in vitro onto the luminal surface of expanded polytetrafluoroethylene (ePTFE) grafts precoated with fibrin glue and fibronectin, then cultivated further for 9 days. 15 macacos were divided randomly into two groups. The common iliac arteries of the exper mental animals (n = 10) were replaced with endothelialized grafts, those of control (n = 5) with untreated ones. RESULTS: The amount of endothelial cells increased for 147.93 +/- 88.68 folds. All the cells were diploid cells with a purity of 99%. The content of both 6-keto-PGF1a and vWF in the supernatant of primary and subcultured passages didn't have significant difference. Two hours and 9 days after cell seeding, the luminal surface of grafts were covered completely by a prominent, spindle-like endothelial monolayer underneath an even fibrin glue matrix could be seen. Nine days after seeding, the dense condensation of cytoskeleton on the luminal and basal side of cells increased apparently. Four weeks after grafts implantation 8/10 of experimental grafts, with a thickness of intima 80 +/- 12 microns, were patent; while the 5 control grafts were occluded. CONCLUSION: The endothelial cell transplantation could effectively increase the patency rate of synthetic blood vessel prosthesis.

Animals↗
PubMed1998

[The pressure of amniotic cavity during pregnancy and treatment of unruptured oligohydramnios with antepartum amnioinfusion].

OBJECTIVES: To measure the pressure of the amniotic cavity during pregnancy and to study the effects of antepartum amnioinfusion on oligohydramnios with intact membranes. METHOD: We used an improved three-way switch apparatus to measure 110 women during pregnancy, and treated 97 oligohydramnios with antepartum amnioinfusion or intravenous infusion as controls. RESULTS: The pressure of the amniotic cavity was 1.69 +/- 0.23 kPa, which was close to the normal value in pregnancy. In oligohydramnios, it was 1.1 +/- 0.3 kPa, and in polyhydramnios 3.2 +/- 0.3 kPa(P < 0.01-0.001). When 300 ml fluid was amnioinfused, the amniotic fluid index (AFI) increased by 5.0 +/- 1.8 cm, the pressure of amniotic cavity increased by 0.18 +/- 0.2/kPa and the incidence of vaginal delivery was 87.9%, whereas that of the control group was 12.1%. There were no fetal distress, asphyxia neonatorum, amnionitis or ruptured membrane. CONCLUSIONS: The pressure of the amniotic cavity during normal pregnancy was stable, but changed with AFI. Antepartum amnioinfusion for unruptured oligohydramnios resulted in a marked increase in incidence of vaginal delivery, a decreased ratio of cesarean section and a reduction of perinatal morbidity. These differences are highly significant.

Adult↗
PubMed1998

[An ELISA assay for humulus scandens specific IgE antibodies].

OBJECTIVE: Humulus scandens pollen (HSP) has been proved to be the one of the most important causative factors of autumnal hay fever in China. We established an enzyme immunoassay for specific IgE against HSP by using monoclonal anti-IgE antibody to detect sIgE in 143 patients with autumnal hay fever and 30 healthy volunteers. METHODS: An indirect method of ELISA was developed. The optimal conditions for the test were: coating the allergen at 4 degrees C overnight with a concentration of 12 micrograms/ml; the test serum was diluted 1:16 and incubated with allergen overnight at 37 degrees C; the most suitable dilution and incubative time of the peroxidase-conjugated mouse anti-human IgE antibody were 1:3,000 and 2 hours respectively. RESULTS: The patients' serum level of sIgE was significantly higher than controls (P < 0.001) and correlated significantly with the degree of skin test reaction (P < 0.01). The concordance between the results of skin test and ELISA was 74%-83%. The specificity of the assay was confirmed by heat inactivation and multiple absorption experiments. The coefficients of variation for the intraassay and interassay reproducibility ranged from 1.20%-8.30% and 8.63%-9.22% respectively. CONCLUSIONS: Determination of specific HSP IgE with ELISA assay shows good specificity, sensitivity and reproducibility. It favours clinical practice due to its lower cost.

Allergens↗
PubMed1998

[The effects of the multiple structural layer of Ti-cast on bond of porcelain fused to titanium].

OBJECTIVE: To study the effects of the multiple structural layer of Ti-cast on the bond of porcelain fused to titanium. METHODS: The interfacial state and bond strength of porcelain-titanium were observed by EPM analysis and a shear test. RESULTS: The results showed cracks were observed in the interface of porcelain-titanium in R1 (the group of multiple structural layer of Ti-cast), but there were no cracks in the interface of porcelain-titanium in R2 (the group of removed multiple structural layer from Ti-cast) and R3 (the group of wrought titanium). The width of elemental diffusion layer of R1, R2 and R3 were 29.03 microns, 6.90 microns and 7.01 microns respectively. The shear bond srength of R1, R2 and R3 were 29.45 MPa, 52.75 MPa and 48.32 MPa respectively. There were significant difference in the width of elemental diffusion layer and shear bond strength between R1 and R2, R3 (P < 0.01). CONCLUSION: This investigation indicates that the multiple structural layer of Ti-cast should be removed before firing of porcelain.

Dental Casting Technique↗
PubMed1998

[Expression of human ScFv against human immunodeficiency virus type 1 gp120].

In order to generate human antibody against HIV-1, using synthetic peptide from HIV-1 gp120 v3 loop as antigen, we screened the recombinant phage antibodies by immunoaffinity and selected positive clones carrying anti-gp120 ScFv gene. The phage DNA was extracted and transformed to E. coli HB2151 that allowed to express soluble ScFv proteins by inducing of IPTG. The results of SDS-PAGE and Western blot showed that the molecular weight of the expressed product is about 28 KD and exhibited anti-c-myc activity. ELISA and Dot blot analysis displayed that the soluble ScFv specifically bound to gp120 and had a higher specificity and affinity. Competitive ELISA further demonstrated that the product was specific to gp120.

Antibodies, Viral↗
PubMed1998

[Study on the experimental infection of hepatitis G virus in rhesus monkey].

In order to study the experimental infection of HGV in rhesus monkey, the monkeys were infected using the plasma from a donor with HGV RNA positive. The second generation monkeys were infected with the sera of the first generation monkeys infected after 6 weeks, and also the third generation monkeys were infected with the sera of the second generation monkeys. HGV RNA were detected by RT-nPCR. The results showed that in sera of infected monkeys HGV RNA were positive after 1 week of inoculation, and were consecutively positive for up to 28 weeks at longest. The level of ALT raised a little in monkey No. 1 and higher than 100 U/L in No. 5. The liver biopsy showed viral hepatitis--like histological changes. Comparing the sequence of HGV 5'LTR from sera of the infected monkeys and the blood donor, the homogeneity, to strain HGU44402 was 98.33% and 95.83% to strain HGU36380 was 92.50% and 89.17%, respectively. The results suggested that the rhesus monkey is sensitive to HGV and is suitable for establishment of an animal model.

Animals↗
PubMed1998

[A physical model for cuff blood pressure measuring technique and its use in the systolic blood pressure measurement].

The traditional blood pressure measurement by oscillometric method is based on statistics theory, so individual error always takes place in measurements. In this paper, we devise not only a technique that can acquire cuff pulse waves undistorted, but also a physical model of cuff measuring process. Using undistorted data and based on this model, we present a new technique for systolic blood pressure measurement. It has been proved to be more accurate than the traditional method.

Blood Pressure Determination↗
PubMed1998

[Column chromatographic preconcentration of trace copper in natural water using dithizone supported on naphthalene and determined by atomic absorption spectrometer].

In this paper a column chromatographic preconcentration method using dithizone supported on naphthalene for copper in natural water is provided. The dissolving reagent is dimethylformamide (DMF). The dissolving solution is determined by atomic absorption spectrometer. The effect of pH, the flow rate of water samples, the choice of dissolving reagent, the effect of diverse ions were studied. RSD is 2.3%. The recoveries for the added standard are between 96%-103%. This method was applied to determined trace copper in natural water samples and standard water samples with satisfactory results.

English Abstract↗
PubMed1997

Determination of catecholamines in sheep plasma by high-performance liquid chromatography with electrochemical detection: comparison of deoxyepinephrine and 3,4-dihydroxybenzylamine as internal standard.

3,4-Dihydroxybenzylamine (DHBA) is commonly used as the internal standard in HPLC catecholamine assays. Sheep are frequently used in studies of cardiovascular physiology and in such studies measurement of catecholamines is important. The recovery of DHBA from sheep plasma is, however variable and poor. Therefore, we have developed a reliable and sensitive HPLC-ED method with alumina extraction for measurement of catecholamines in sheep plasma using deoxyepinephrine (epinine) as the internal standard. Separation was performed on a muBondapak C18 column (300x3.9 mm, 10 microm) with a mobile phase containing 2% acetonitrile and 98% buffer (0.05% sodium acetate-0.02% EDTA-0.013% sodium heptanesulfonate), pH 3.25. The extraction of epinine from water, human plasma, dog plasma and sheep plasma did not differ (p>0.05), but extraction of DHBA from sheep plasma was significantly impaired (p<0.0001). The R2 of regression curves (n=5) of norepinephrine (NE) (25.02 pg/ml-1.00 ng/ml) and epinephrine (E) (25.82 pg/ml-1.03 ng/ml), using epinine as internal standard were greater than 0.99. The intra- and inter-day coefficients of variation were 2.11-11.15 and 0.88-12.60% for NE and 1.12-10.91 and 2.88-12.60% for E, respectively. The detection limits for NE and E are 12 pg/ml. The technique described has the advantage that it allows the simultaneous determination of both endogenous and [3H]norepinephrine in sheep plasma using a sensitive and reproducible HPLC technique.

Animals↗
PubMed1997

Maintenance of calcium homeostasis in the endoplasmic reticulum by Bcl-2.

The oncogene bcl-2 encodes a 26-kD protein localized to intracellular membranes, including the ER, mitochondria, and perinuclear membrane, but its mechanism of action is unknown. We have been investigating the hypothesis that Bcl-2 regulates the movement of calcium ions (Ca2+) through the ER membrane. Earlier findings in this laboratory indicated that Bcl-2 reduces Ca2+ efflux from the ER lumen in WEHI7.2 lymphoma cells treated with the Ca2+-ATPase inhibitor thapsigargin (TG) but does not prevent capacitative entry of extracellular calcium. In this report, we show that sustained elevation of cytosolic Ca2+ due to capacitative entry is not required for induction of apoptosis by TG, suggesting that ER calcium pool depletion may trigger apoptosis. Bcl-2 overexpression maintains Ca2+ uptake in the ER of TG-treated cells and prevents a TG-imposed delay in intralumenal processing of the endogenous glycoprotein cathepsin D. Also, Bcl-2 overexpression preserves the ER Ca2+ pool in untreated cells when extracellular Ca2+ is low. However, low extracellular Ca2+ reduces the antiapoptotic action of Bcl-2, suggesting that cytosolic Ca2+ elevation due to capacitative entry may be required for optimal ER pool filling and apoptosis inhibition by Bcl-2. In summary, the findings suggest that Bcl-2 maintains Ca2+ homeostasis within the ER, thereby inhibiting apoptosis induction by TG.

Animals↗
PubMed1997

Baculovirus p35 and Z-VAD-fmk inhibit thapsigargin-induced apoptosis of breast cancer cells.

Programmed cell death, or apoptosis, is inhibited by the antiapoptotic oncogene, Bcl-2, and is mediated by a cascade of aspartate-specific cysteine proteases, or caspases, related to interleukin 1-beta converting enzyme. Depending on cell type, apoptosis can be induced by treatment with thapsigargin (TG); a selective inhibitor of the endoplasmic reticulum-associated calcium-ATPase. The role of caspases in mediating TG-induced apoptosis was investigated in the Bcl-2-negative human breast cancer cell line, MDA-MB-468. Apoptosis developed in MDA-MB-468 cells over a period of 24-72 h following treatment with 100 nM TG, and was prevented by Bcl-2 overexpression. TG-induced apoptosis was associated with activation of caspase-3 and was inhibited by stable expression of the baculovirus p35 protein, an inhibitor of caspase activity. Also, TG-induced apoptosis was inhibited by treating cells with Z-VAD-fmk, a cell-permeable fluoromethylketone inhibitor of caspases. These findings indicate that TG-induced apoptosis of MDA-MB-468 breast cancer cells is subject to inhibition by Bcl-2 and is mediated by caspase activity. This model system should be useful for further investigation directed toward understanding the role of calcium in signaling apoptosis, and its relationship to Bcl-2 and the caspase proteolytic cascade.

Amino Acid Chloromethyl Ketones↗
PubMed1997

On-the-fly fluorescence lifetime detection of labeled DNA primers.

The first application of frequency-domain, on-the-fly fluorescence lifetime detection to the detection, identification and resolution of fluorescent labeled oligonucleotide primers in capillary electrophoresis is presented. These studies, which are directed towards the development of four-decay DNA sequencing, employed two common sequencing primers, SP6 and M13/pUC. The primers were each tagged by a derivative of either fluorescein or BODIPY. Fluorescence emission maxima and lifetimes of the free dyes and the labeled primers were determined both in batch mode and on-the-fly in capillary electrophoresis. Fluorescence intensity and lifetime electropherograms were extracted from dynamic lifetime data that were acquired at 0.1-s intervals during the CE separation. Lifetimes were recovered using either conventional non-linear least-squares analysis or the self-modeling maximum entropy method, which does not require prior knowledge of the system. Based on migration time and fluorescence lifetime, peaks could be detected and identified, and co-eluting peaks could be resolved. Interference from background impurities and scattered light was greatly reduced by the combination of physical separation and lifetime resolution.

DNA Primers↗