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Biomedical subjects

X Chen

Publications and source records attributed to X Chen.

At least 73 records · Page 4Linked to original sources
PubMed2005

Using cellular automata to generate image representation for biological sequences.

A novel approach to visualize biological sequences is developed based on cellular automata (Wolfram, S. Nature 1984, 311, 419-424), a set of discrete dynamical systems in which space and time are discrete. By transforming the symbolic sequence codes into the digital codes, and using some optimal space-time evolvement rules of cellular automata, a biological sequence can be represented by a unique image, the so-called cellular automata image. Many important features, which are originally hidden in a long and complicated biological sequence, can be clearly revealed thru its cellular automata image. With biological sequences entering into databanks rapidly increasing in the post-genomic era, it is anticipated that the cellular automata image will become a very useful vehicle for investigation into their key features, identification of their function, as well as revelation of their "fingerprint". It is anticipated that by using the concept of the pseudo amino acid composition (Chou, K.C. Proteins: Structure, Function, and Genetics, 2001, 43, 246-255), the cellular automata image approach can also be used to improve the quality of predicting protein attributes, such as structural class and subcellular location.

Animals↗
PubMed2005

Photocatalytic degradation of azo dyes by nitrogen-doped TiO2 nanocatalysts.

This study examined the photocatalytic degradation of three azo dyes, acid orange 7 (AO7), procion red MX-5B (MX-5B) and reactive black 5 (RB5) using a new type of nitrogen-doped TiO2 nanocrystals. These newly developed doped titania nanocatalysts demonstrated high reactivity under visible light (lambda>390 nm), allowing more efficient usage of solar light. The doped titania were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Experiments were conducted to compare the photocatalytic activities of nitrogen-doped TiO2 nanocatalysts and commercially available Degussa P25 powder using both UV illumination and solar light. It is shown that nitrogen-doped TiO2 after calcination had the highest photocatalytic activity among all three catalysts tested, with 95% of AO7 decolorized in 1 h under UV illumination. The doped TiO2 also exhibited substantial photocatalytic activity under direct sunlight irradiation, with 70% of the dye color removed in 1h and complete decolorization within 3 h. Degussa P25 did not cause detectable dye decolorization under identical experimental conditions using solar light. The decrease of total organic carbon (TOC) and evolution of inorganic sulfate (SO4(2-)) ions in dye solutions were measured to monitor the dye mineralization process.

Azo Compounds↗
PubMed2005

Gender and environmental effects on regional brain-derived neurotrophic factor expression after experimental traumatic brain injury.

Alterations in brain-derived neurotrophic factor expression have been reported in multiple brain regions acutely after traumatic brain injury, however neither injury nor post-injury environmental enrichment has been shown to affect hippocampal brain-derived neurotrophic factor gene expression in male rats chronically post-injury. Studies have demonstrated hormone-related neuroprotection for female rats after traumatic brain injury, and estrogen and exercise both influence brain-derived neurotrophic factor levels. Despite recent studies suggesting that exposure post-traumatic brain injury to environmental enrichment improves cognitive recovery in male rats, we have shown that environmental enrichment mediated improvements with spatial learning are gender specific and only positively affect males. Therefore the purpose of this study was to evaluate the effect of gender and environmental enrichment on chronic post-injury cortical and hippocampal brain-derived neurotrophic factor protein expression. Sprague-Dawley male and cycling female rats were placed into environmental enrichment or standard housing after controlled cortical impact or sham surgery. Four weeks post-surgery, hippocampal and frontal cortex brain-derived neurotrophic factor expression were examined using Western blot. Results revealed significant increases in brain-derived neurotrophic factor expression in the frontal cortex ipsilateral to injury for males (P=0.03). Environmental enrichment did not augment this effect. Neither environmental enrichment nor injury significantly affected cortical brain-derived neurotrophic factor expression for females. In the hippocampus ipsilateral to injury brain-derived neurotrophic factor expression for both males and females was half (49% and 51% respectively) of that observed in shams housed in the standard environment. For injured males, there was a trend in this region for environmental enrichment to restore brain-derived neurotrophic factor levels to sham values. However, there were robust increases in hippocampal brain-derived neurotrophic factor expression ipsilateral to the injury for injured females in environmental enrichment compared with both sham and injured females placed in standard housing (P<or=0.005). In the hippocampus contralateral to injury, there were also significant injury-related increases in brain-derived neurotrophic factor expression for females (P<or=0.05) that were not further augmented by environmental enrichment. These results show significant, region-specific gender differences in brain-derived neurotrophic factor expression with both injury and environmental enrichment that may be important for recovery. However, these data do not support a critical role for brain-derived neurotrophic factor in environmental enrichment mediated improvements with spatial learning.

Actins↗
PubMed2005

Sildenafil citrate treatment for erectile dysfunction after kidney transplantation.

OBJECTIVE: Our goal was to analyze the morbidity of organic erectile dysfunction (ED) in kidney-transplant patients and to evaluate the efficacy and reliability of sildenafil citrate treatment. METHOD: Sixty-five ED patients with normal graft function for 3 to 12 months after kidney transplantation were involved in our study. Erectile dysfunction was diagnosed in all the patients by the International Index of Erectile Dysfunction (IIEF). Among them, 10 patients were in light degree; 32 patients in moderate degree, and 23 patients in severe degree according to IIEF score. All of the patients underwent medical history, physical and chemical examinations. In each patient, the IIEF score, blood urea nitrogen, creatinine, and trough concentrations of cyclosporine were compared before and after taking sildenafil citrate at an initial dose of 50 mg every night. RESULTS: Twenty-six patients without ED before transplantation suffered ED after the operation, and 32 patients with ED before transplantation noticed worsening. Taking sildenafil citrate was effective in 53 patients (81.54%). There were no statistical differences in blood urea nitrogen, creatinine, or trough concentrations of cyclosporine in patients before and after sildenafil treatment. CONCLUSIONS: The morbidity of organic erectile dysfunction increased after transplantation. Sildenafil citrate treatment for ED in kidney-transplant patients was effective and safe. Graft function and trough concentrations of cyclosporine were not affected by sildenafil citrate.

Blood Urea Nitrogen↗
PubMed2005

The Ad5 fiber mediates nonviral gene transfer in the absence of the whole virus, utilizing a novel cell entry pathway.

The interesting discovery reported here that soluble adenovirus serotype 5 (Ad5) fiber proteins enter cells without the virus was a serendipitous result during our development of Ad5 capsid proteins as nonviral gene transfer vectors. The Ad5 capsid fiber and penton proteins mediate infection. The fiber docks to a noninternalizing cell surface protein called the coxsackievirus-Ad receptor (CAR), followed by penton binding to integrins, triggering integrin-mediated endocytosis of the virus. In our previous work, we assembled the nonviral complex, 3PO, which utilized the penton to mediate gene transfer through integrin binding and endocytosis. Here, we tested whether incorporating the fiber targets 3PO to CAR, thus recapitulating the Ad5 infection pathway. As CAR is not an endocytic receptor, we were surprised to find that the fiber alone, without the penton, enabled gene transfer by binding CAR, but internalizing through an unknown mechanism. We show here that the fiber distributes to the nucleus and cytoplasm after temperature-independent uptake, whereas the penton accumulates around the nucleus after temperature-dependent uptake. Fiber uptake by HeLa cells is also actin-dependent, requires the fiber tail/shaft region, and is largely inhibited by heparin. This study raises the possibility that alternative pathways may enable both viral and nonviral cell entry.

Capsid Proteins↗
PubMed2005

Sustained release of ganciclovir from poly(lactide-co-glycolide) microspheres.

Biodegradable poly(lactide-co-glycolide) microspheres loaded with ganciclovir were produced using the emulsification/solvent evaporation technique. The effects of drug-to-polymer ratio and dispersion time on the drug content in the microspheres were investigated. The release rate of the drug was studied for 20 weeks in a phosphate buffered solution of pH 7 at 37 degrees C. Data revealed that lower drug content was obtained with increasing drug-to-polymer ratio and decreasing dispersion time. The release of the drug followed a triphasic release pattern, i.e. an initial burst, a diffusive phase and a second burst. The initial burst occurred within the first 2 days of immersion. After the burst, the release was by diffusion for up to 13 weeks, followed by another burst release, which signals the onset of bulk degradation of the polymer. Gel permeation chromatography (GPC), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and ultraviolet spectroscopy (UV) were used to follow the hydrolytic degradation and drug release rate of the microspheres.

Antiviral Agents↗
PubMed2005

Workplace and HIV-related sexual behaviours and perceptions among female migrant workers.

Data from 1,543 female migrants working in eight occupational clusters in Beijing and Nanjing, China were analysed to examine the association of workplace with HIV-related behaviours and perceptions. For sexually experienced women (n = 666, 43.2%), those working in entertainment establishments or personal service (e.g., nightclubs, dancing halls, barbershops, beauty salons, massage parlours, etc.) engaged in risky sexual practices twice as frequently as those working in non-entertainment establishments (e.g. restaurants, stalls, domestic service, factories, etc.). About 10% of women in the entertainment establishments reported having sold sex, 30% having multiple sexual partners and 40% having sex with men with multiple sexual partners. The rate of consistent condom use was less than 15%. They also tended to have a higher level of perceptions of both peer risk involvement and positive expectancy of risk behaviours, and lower perceptions of severity of STDs and HIV. For women who were not sexually experienced, those working in 'stalls' or 'domestic service' tended to perceive higher peer risk involvement, less severity of HIV infection, and less effectiveness of protective behaviour. The occupational pattern of sexual risk behaviours and perceptions observed in the current study indicates employment conditions are associated with HIV risk. Intervention strategies should be tailored to address occupational-related factors.

Adolescent↗
PubMed2005

An investigation of the effects of TETRA RF fields on intracellular calcium in neurones and cardiac myocytes.

PURPOSE: This study aimed to determine whether Terrestrial Trunked Radio (TETRA) fields can affect intracellular calcium signalling in excitable cells. MATERIALS AND METHODS: Intracellular calcium concentration ([Ca(2 +) ](i)) was measured in cultured rat cerebellar granule cells and cardiac myocytes during exposure to TETRA fields (380.8875 MHz pulse modulated at 17.6 Hz, 25% duty cycle). [Ca(2 +) ](i) was measured as fura-PE3, fluo-3 or fluo-4 fluorescence by digital image analysis. RESULTS: Granule cells exposed at specific absorption rates (SARs) of 5, 10, 20, 50 or 400 mW x kg(-1) showed no significant changes in resting [Ca(2 +) ](i). Increases in [Ca(2 +) ](i) in response to potassium-induced depolarization were significantly different from sham controls in TETRA-exposed cells, but the majority of the difference was attributable to initial biological variation between cell cultures. No difference was found between fura-PE3 (UV excitation) and fluo-3 (visible light excitation) measurements in these cells. Exposure to TETRA (50 or 400 mW x kg(-1)) had no significant effect on either the rate or amplitude of spontaneous Ca(2 +) transients in cardiac myocytes. The cells showed normal responses to salbutamol (50 microM) and acetylcholine (10 microM). CONCLUSIONS: Overall, these results showed no evidence of any consistent or biologically relevant effect of TETRA fields on [Ca(2 + )](i) in granule cells and cardiac myocytes at any of the SAR tested.

Animals↗
PubMed2005

Associations of lifestyle factors with quality of life (QOL) in Japanese children: a 3-year follow-up of the Toyama Birth Cohort Study.

PURPOSE: To examine the associations between lifestyle factors and quality of life (QOL) among Japanese children. METHODS: Participants were 7794 children (3869 boys and 3925 girls) aged 9-10. They completed a questionnaire regarding lifestyles at baseline survey and were followed up for 3 years. In the follow-up survey, QOL was evaluated using a Japanese version of the COOP charts. Children rated their QOL as one of five response categories. Subjects rated as 'very well' or 'pretty good' were considered to have good QOL, and the remainder was assumed to have poor QOL. Logistic regression analysis was performed to evaluate the relationship between lifestyles or changes in lifestyles and QOL. In the multivariate analysis model, age, sex, body mass index (BMI), and lifestyle factors were simultaneously entered. RESULTS: During the follow-up period, children became more sedentary. Compared to children participating in physical activity 'very often' at baseline, those who exercised 'almost never' were more likely to have poor QOL [OR (95% CI): 1.92 (1.26-2.93)]. Children who developed or maintained undesirable lifestyles had high OR for poor QOL. Compared to children taking breakfast 'often' during the follow-up period, those changing from 'often' to 'seldom' or those taking breakfast 'seldom' were more likely to have poor QOL [1.61 (1.24-2.07), 2.05 (1.03-4.09), respectively]. When compared with children maintaining their participation in physical activity 'often', those who changed from 'often' to 'seldom' and those who kept 'seldom' were more likely to have poor QOL [2.10 (1.84-2.39), 2.21 (1.88-2.59), respectively]. CONCLUSIONS: This study shows that unfavourable lifestyles in childhood are associated with poor QOL in early adolescence. Early intervention could be worth considering to keeping desirable lifestyles during childhood.

Adolescent↗
PubMed2005

Response of crayfish, Procambarus clarkii, haemocytes infected by white spot syndrome virus.

White spot syndrome virus (WSSV) is a serious pathogen of aquatic crustaceans. Little is known about its transmission in vivo and the immune reaction of its hosts. In this study, the circulating haemocytes of crayfish, Procambarus clarkii, infected by WSSV, and primary haemocyte cultures inoculated with WSSV, were collected and observed by transmission electron microscopy and light microscopy following in situ hybridization. In ultra-thin sections of infected haemocytes, the enveloped virions were seen to be phagocytosed in the cytoplasm and no viral particles were observed in the nuclei. In situ hybridization with WSSV-specific probes also demonstrated that there were no specific positive signals present in the haemocytes. Conversely, strong specific positive signals showed that WSSV replicated in the nuclei of gill cells. As a control, the lymphoid organ of shrimp, Penaeus monodon, infected by WSSV was examined by in situ hybridization which showed that WSSV did not replicate within the tubules of the lymphoid organ. In contrast to previous studies, it is concluded that neither shrimp nor crayfish haemocytes support WSSV replication.

Animals↗
PubMed2005

Topiramate ameliorates hyperglycaemia and improves glucose-stimulated insulin release in ZDF rats and db/db mice.

Topiramate (TPM) is a novel neurotherapeutic agent. Clinical studies reported that TPM treatment reduced body weight and decreased fasting blood glucose levels in obese patients with or without type 2 diabetes. It is unclear whether the blood glucose-normalizing phenomenon observed during TPM treatment is a primary effect or the consequence of reduced food intake and weight loss. In the present studies, we chronically treated female Zucker diabetic fatty (ZDF) rats (fed with a diabetogenic diet) and db/db mice with TPM (30-300 mg/kg/day) to examine the effect of TPM on hyperglycaemia and its relationship with food intake and body weight gain. Our data showed that TPM treatment markedly reduced blood glucose levels in both ZDF rats and db/db mice without a significant reduction in body weight gain. Pair-fed db/db mice treated with the vehicle alone did not exhibit a significant decrease in blood glucose levels compared with mice fed ad libitum. TPM treatment increased glucose-stimulated insulin release by 2-3-fold during an oral glucose tolerance test in both ZDF rats and db/db mice. We also observed a 1.4-fold increase of pancreatic insulin content and heightened insulin immunostaining in pancreatic beta cells in db/db mice treated with TPM. Our data suggest that the antidiabetic effect of TPM is independent of the changes in body weight gain and food intake. Improved glucose-induced insulin release may, in part, underlie the mechanisms by which TPM ameliorates the hyperglycaemia.

Abdomen↗
PubMed2005

Pharmacological profile of a novel, non-TZD PPARgamma agonist.

AIM: The purpose of this study was to characterize a novel, non-thiazolidinedione (TZD) peroxisome proliferator-activated receptor (PPAR)gamma agonist, RWJ-348260, via both in vitro and in vivo approaches. METHODS: The in vitro PPARgamma activities of RWJ-348260 were assessed in PPARgamma-GAL4 co-transfection assay, PPARgamma receptor binding assay, aP2 gene induction assay and preadipocyte differentiation assay. The in vivo efficacy of the compound was determined in rodent genetic diabetes models [ob/ob mouse, db/db mouse and Zucker diabetic fatty (ZDF) rat] following multiple days of oral administration. RESULTS: RWJ-348260 selectively activated PPARgammain vitro. In vivo, RWJ-348260 produced significant decreases in plasma glucose, HbA1c, insulin and triglyceride levels. RWJ-348260 also dose-dependently improved oral glucose tolerance. In db/db mice, the compound up-regulated PPARgamma target genes in white adipose tissues. RWJ-348260 produced a lower extent of hepatocyte lipid deposition and a smaller increase in liver weight compared to rosiglitazone in db/db mice. While RWJ-348260 effectively normalized hyperglycaemia and dyslipidaemia, it did not change haematocrit, transaminase, alkaline phosphatase, total bilirubin levels or liver weights in ZDF rats. CONCLUSIONS: RWJ-348260 is a potent PPARgamma agonist with efficacious antidiabetic activity in diabetic animal models. The compound has an improved side-effect profile compared to rosiglitazone.

Adipocytes↗
PubMed2005

Controlled cortical impact injury affects dopaminergic transmission in the rat striatum.

The therapeutic benefits of dopamine (DA) agonists after traumatic brain injury (TBI) imply a role for DA systems in mediating functional deficits post-TBI. We investigated how experimental TBI affects striatal dopamine systems using fast scan cyclic voltammetry (FSCV), western blot, and d-amphetamine-induced rotational behavior. Adult male Sprague-Dawley rats were injured by a controlled cortical impact (CCI) delivered unilaterally to the parietal cortex, or were naïve controls. Amphetamine-induced rotational behavior was assessed 10 days post-CCI. Fourteen days post-CCI, animals were anesthetized and underwent FSCV with bilateral striatal carbon fiber microelectrode placement and stimulating electrode placement in the medial forebrain bundle (MFB). Evoked DA overflow was assessed in the striatum as the MFB was electrically stimulated at 60 Hz for 10 s. In 23% of injured animals, but no naïve animals, rotation was observed with amphetamine administration. Compared with naïves, striatal evoked DA overflow was lower for injured animals in the striatum ipsilateral to injury (p < 0.05). Injured animals exhibited a decrease in V(max) (52% of naïve, p < 0.05) for DA clearance in the hemisphere ipsilateral to injury compared with naïves. Dopamine transporter (DAT) expression was proportionally decreased in the striatum ipsilateral to injury compared with naïve animals (60% of naïve, p < 0.05), despite no injury-related changes in vesicular monoamine transporter or D2 receptor expression (DRD2) in this region. Collectively, these data appear to confirm that the clinical efficacy of dopamine agonists in the treatment of TBI may be related to disruptions in the activity of subcortical dopamine systems.

Animals↗
PubMed2005

A novel mechanism prevents the development of hypertension during chronic cold stress.

1 Chronic cold exposure of rats (7 days in a cold room at 4 degrees C) attenuated the sympathetic nerve stimulation (NS)-induced overflow of noradrenaline (NE) (measured by high-performance liquid chromatography, coupled to electrochemical detection) appearing in the perfusate/superfusate of the perfused mesenteric arterial bed as well as the increase in the perfusion pressure. 2 The same type of cold exposure resulted in an increase in tyrosine hydroxylase (TH) gene expression measured in the superior cervical ganglion and NE content measured in the mesenteric artery obtained from cold-exposed rats. 3 Addition of sodium nitroprusside, a nitric oxide (NO) donor, to the buffer perfusing the mesenteric arterial bed obtained from rats maintained at room temperature also resulted in an attenuation of the NS-induced overflow of NE and increase in perfusion pressure. 4 N(c)-nitro-L-arginine methyl ester (L-NAME), an NO synthase inhibitor, placed in the drinking water prevented the attenuation of the pre- and post-junctional responses to NS of the mesenteric arterial bed obtained from cold-exposed rats. 5 L-NAME treatment also increased the cold-induced elevation of blood pressure seen in whole animals. 6 The present results are consistent with the idea that cold exposure leads to a concomitant increase in sympathetic nerve activity and production of NO. We hypothesize that the increase in production and release of NO results in a decrease in the biologically active form of NE despite increased synthesis and release of the catecholamine. 7 It is concluded that the above-mentioned interactions serve as a protective mechanism offsetting the increased release and action of NE from sympathetic nerves and thus preventing the development of hypertension.

Animals↗
PubMed2005

Characterization of a serodiagnostic complement fixation antigen of Coccidioides posadasii expressed in the nonpathogenic Fungus Uncinocarpus reesii.

Coccidioides spp. (immitis and posadasii) are the causative agents of human coccidioidomycosis. In this study, we developed a novel system to overexpress coccidioidal proteins in a nonpathogenic fungus, Uncinocarpus reesii, which is closely related to Coccidioides. A promoter derived from the heat shock protein gene (HSP60) of Coccidioides posadasii was used to control the transcription of the inserted gene in the constructed coccidioidal protein expression vector (pCE). The chitinase gene (CTS1) of C. posadasii, which encodes the complement fixation antigen, was expressed using this system. The recombinant Cts1 protein (rCts1(Ur)) was induced in pCE-CTS1-transformed U. reesii by elevating the cultivation temperature. The isolated rCts1(Ur) showed chitinolytic activity that was identical to that of the native protein and had serodiagnostic efficacy comparable to those of the commercially available antigens in immunodiffusion-complement fixation tests. Using the purified rCts1(Ur), 74 out of the 77 coccidioidomycosis patients examined (96.1%) were positively identified by enzyme-linked immunosorbent assay. The rCts1(Ur) protein showed higher chitinolytic activity and slightly greater seroreactivity than the bacterially expressed recombinant Cts1. These data suggest that this novel expression system is a useful tool to produce coccidioidal antigens for use as diagnostic antigens.

Antigens, Fungal↗
PubMed2005

Left ventricular myocardial mass determination by contrast enhanced colour Doppler compared with magnetic resonance imaging.

OBJECTIVE: To assess the feasibility of using contrast enhanced colour Doppler echocardiography to determine left ventricular (LV) mass and to compare its accuracy with LV mass obtained by magnetic resonance imaging (MRI). METHODS: Images were acquired in the short axis plane of the heart, derived from coronal and sagittal scout views and double oblique angulation. The LV mass was calculated by two methods: Simpson's rule and the area-length method. Levovist (Schering AG, Berlin, Germany) 2.5 g was given by slow intravenous bolus or infusion over about 45 seconds for contrast imaging. LV images were captured in the apical two chamber, four chamber, and three chamber views. Each contrast harmonic colour Doppler image was converted to a cavity-only image by simple image mathematics. RESULTS: 27 (77.1%) of the patients (mean (SD) age 66.2 (8.9) years) were men. There was a mean (SD) interval of 6.6 (8.6) days (range 0-27 days) between echocardiography and MRI. The mean (SD) LV mass determined by MRI Simpson's rule method was 171.0 (52.4) g (range 105.1-318.7 g). The mean LV mass (SD) determined by the echocardiographic Simpson's rule method was 178.2 (47.0) g (range 112.6-307.6 g). The mean (SD) MRI area-length LV mass was 187.3 (64.5) g (range 109.0-393.6 g). The linear regression correlation between LV mass determined by MRI Simpson's and echocardiographic Simpson's methods was excellent (y = 1.022x, R2 = 0.986) with a mean (SD) difference of 7.20 (20.9) g. The linear regression correlation between the MRI area-length LV mass and MRI Simpson's LV mass was excellent (y = 1.101x, R2 = 0.989) with a mean (SD) difference of 16.3 (22.3) g. CONCLUSIONS: LV mass may be obtained reliably by contrast enhanced colour Doppler and two dimensional echocardiography. The contrast Doppler method accurately determines LV mass with excellent agreement with the MRI technique.

Aged↗
PubMed2005

Relation of sexual risks and prevention practices with individuals' stigmatising beliefs towards HIV infected individuals: an exploratory study.

OBJECTIVE: To investigate how an individual's stigmatising beliefs towards people living with HIV are related to his or her own sexual risk and protective behaviours. METHODS: A cross sectional survey was conducted to assess HIV related stigmatising beliefs, risk sexual behaviours, and preventive practices among sexually experienced rural to urban migrants aged 18-30 years in 2002 in Beijing and Nanjing, two large Chinese cities. RESULTS: Among 2153 migrants, 7.2% reported having had more than one sexual partner in the previous month, 9.9% had commercial sex partners, and 12.5% had an episode of a sexually transmitted disease (STD). Only 18% reported frequently or always using condoms, with 20% sometimes or occasionally using them. 57% of the Chinese migrants were willing to take a voluntary HIV test, and 65% had HIV related stigmatising beliefs towards people living with HIV. Multiple logistic regression analysis depicts that individual's stigmatising beliefs towards people with HIV were positively associated with having had an episode of an STD, having multiple sex partners, or having had commercial sex partners, and were negatively associated with condom use and the willingness to accept an HIV test. CONCLUSION: The finding that one's own stigmatising belief is a potential barrier to HIV related preventive practices highlights the difficulties and challenges in implementing behavioural interventions.

Adolescent↗