Biomedical subjects

Xiaoming Li

Publications and source records attributed to Xiaoming Li.

At least 37 records · Page 2Linked to original sources

PubMed2006

Short-term effect of a cultural adaptation of voluntary counseling and testing among female sex workers in China: a quasi-experimental trial.

This study evaluates the efficacy of cultural adaptation of a voluntary counseling and testing (VCT) intervention, in increasing condom use and decreasing rates of sexually transmitted diseases (STDs) among a group of female sex workers (FSWs) in Guangxi, China. This intervention is modeled after the "state-of-the-science" VCT program that was developed and evaluated by the Center for Disease Control and Prevention's Project RESPECT. Four hundred FSWs were assigned to either an intervention group receiving the VCT intervention or a control group receiving standard of care STD testing and treatment. Data were collected at baseline and 6 months postintervention. Outcome measures included HIV/STD related knowledge and perceptions, condom use, and history of STDs. Five common STDs were screened and tested through clinical examination and laboratory testing to serve as biomarkers. After controlling for potential confounders and baseline differences, the VCT intervention group was significantly higher than the control group in HIV/STD related knowledge (p < .0001) and consistent condom use with clients (odds ration [OR] = 2.23; 95% confidence interval [CI] = 1.26-3.96) at 6 months follow-up. In addition, the intervention group had a significantly lower infection rate of STDs than the control group at follow-up (OR = 0.44; 95% CI = 0.24-0.80). This quasi-experimental trial provides evidence that the brief VCT intervention, through appropriate cultural adaptation, can be efficacious in increasing condom use and reducing STD infection rate among FSWs in China.

Adult↗

PubMed2006

[Clinical significance of lymph vessel density marked by lymphatic vessel endothelial hyaluronic acid receptor-1 in laryngeal squamous cell carcinomas].

OBJECTIVE: To study the relationship between density, location, proliferation of lymph vessels and clinicopathological features of laryngeal squamous carcinoma. METHOD: Tumor lymph vessels were quantitated and located in archival specimens of laryngeal carcinoma by LSAB immunostaining for the recently described lymphatic endothelial marker LYVE-1. The Ki67 proliferation marker was used to evaluate the proliferating conditions of LYVE-1(+) vessels with EnVision immunohistochemical methods. RESULT: (1) The density of intratumoral LYVE-1(+) vessels was higher in the cases of neck lymph nodal metastasis group than that of no neck lymph nodal metastasis group (P = 0.000). There was a significant difference of the density of intratumoral LYVE-1(+) vessels in the cases of T1, T2 and T(3-4) group. There was no significant difference of the density of intratumoral LYVE-1(+) vessels between supraglottic group and glottic group, squamous cell histological types I group and types II group (P = 0.125, 0.146, respectively). (2) The density of peritumoral LYVE-1(+) vessels was higher in the cases of neck lymph nodal metastasis group than that of no neck lymph nodal metastasis group. However,there was no statistic significance (P = 0.253). (3) Ki67(+) immunostaining occurs in some of the intratumoral LYVE-1(+) vessels, interestingly, there was no this phenomenon in the peritumoral LYVE-1(+) vessels. CONCLUSION: Intratumoral lymph vessel density marked by LYVE-1 in laryngeal carcinoma was significantly correlated with tumor infiltration and metastasis. Our results provide potent evidence that proliferating lymphatics exists in intratumoral areas of laryngeal carcinoma mainly which maybe contribute to lymph node metastasis in some cases.

Adult↗

PubMed2006

[Expression of Survivin and its correlation with tumor angiogenesis in differentiated thyroid carcinomas].

OBJECTIVE: To identify the expression of Survivin and its relationship with tumor angiogenesis in differentiated thyroid carcinomas. METHOD: The expression of Survivin, VEGF and MVD were detected by immuno-histochemical staining (SP methods) in 47 differentiated thyroid carcinomas, 10 thyroid adenoma and 10 normal thyroid tissues and their content were measured by pathological image analysis system. RESULT: The expression of Survivin and VEGF in differentiated thyroid carcinomas was 46.8% and 61.7%, respectively. No expression of Survivin was detected in thyroid adenoma and normal thyroid tissues. The expression of Survivin was significantly correlated with the expression of VEGF and MVD in differentiated thyroid carcinomas. The expression of Survivin was significantly associated with clinical stages, tumor complete capsule and lymph node metastasis. CONCLUSION: The up-regulation of Survivin expression and its close relationship with angiogenesis may play an important role in carcinogenesis and development of differentiated thyroid carcinomas.

Adolescent↗

PubMed2006

[Management in squamous cell carcinoma of maxillary sinus with orbital invasion].

OBJECTIVE: To explore the orbital management in advanced squamous cell carcinoma of maxillary sinus with orbital invasion. METHOD: Forty-six postoperative cases of advanced squamous cell carcinoma of maxillary sinus with orbital invasion were followed up. Two,three,five-year survival rates and 2-year recurrence rates were analysed in,orbital bone invaded group, periorbit invaded group and orbital content invaded group. RESULT: Two, three,five-year survival rates and 2-year recurrence rates were 65.2%, 55.6%, 46.7% and 38.1% in orbital bone invaded group; 57.1%, 50.0%, 45.5% and 53.8% in periorbit invaded group; 44. 4%, 37. 5%, 37. 5% and 62. 5% in orbital content invaded group, respectively. Survival rates of three groups descended and recurrence rates of three groups ascended but without statistical significance( P >0. 05). CONCLUSION: During the surgery for advanced squamous cell carcinoma of maxillary sinus with orbital invasion without the evidence of optical nerve and eye ball involvement, preservation of orbital contents is considerable even though the orbital bone and periorbit are involved by the tumor.

Adult↗

PubMed2005

Collagen-based implants reinforced by chitin fibres in a goat shank bone defect model.

Tissue engineering is an increasingly popular method for repairing bone defects. However, repair of bone defects over 30 mm using tissue-engineering methods is a difficult clinical problem. In this study, we used a goat shank model to evaluate the bone-regenerating efficacy of a novel nano-hydroxyapatite/collagen/PLLA (nHACP) composite reinforced by chitin fibres. Forty adult male goats with 40 mm defects in shank at the same anatomic site were divided into four groups. The first group was the control, where nothing was implanted in the defect (defect group). The other three groups were implanted with porous pure PLLA, nHACP and nHACP reinforced by chitin fibres, respectively. Bone growth in each group was evaluated by radiography, histology, bone mineral density and mechanical strength, once every 5 weeks for 15 weeks. The results indicated that nHACP implants, both with and without chitin fibres, are better for repairing the defects than pure PLLA. However, only the reinforced implants showed nearly perfect recovery in 15 weeks after operation. So, the reinforced scaffold might be a candidate for bone tissue repair.

Animals↗

PubMed2005

Mutations in MTO2 related to tRNA modification impair mitochondrial gene expression and protein synthesis in the presence of a paromomycin resistance mutation in mitochondrial 15 S rRNA.

Nuclear gene(s) have been shown to modulate the phenotypic expression of mitochondrial DNA mutations. We report here the identification and characterization of the yeast nuclear gene MTO2 encoding an evolutionarily conserved protein involved in mitochondrial tRNA modification. Interestingly, mto2 null mutants expressed a respiratory-deficient phenotype when coexisting with the C1409G mutation of mitochondrial 15 S rRNA at the very conservative site for human deafness-associated 12 S rRNA A1491G and C1409T mutations. Furthermore, the overall rate of mitochondrial translation was markedly reduced in a yeast mto2 strain in the wild type mitochondrial background, whereas mitochondrial protein synthesis was almost abolished in a yeast mto2 strain carrying the C1409G allele. The other interesting feature of mto2 mutants is the defective expression of mitochondrial genes, especially CYTB and COX1, but only when coexisting with the C1409G allele. These data strongly indicate that a product of MTO2 functionally interacts with the decoding region of 15 S rRNA, particularly at the site of the C1409G or A1491G mutation. In addition, we showed that yeast and human Mto2p localize in mitochondria. The isolated human MTO2 cDNA can partially restore the respiratory-deficient phenotype of yeast mto2 cells carrying the C1409G mutation. These functional conservations imply that human MTO2 may act as a modifier gene, modulating the phenotypic expression of the deafness-associated A1491G or C1409T mutation in mitochondrial 12 S rRNA.

Alleles↗

PubMed2005

TNF-alpha induced c-IAP1/TRAF2 complex translocation to a Ubc6-containing compartment and TRAF2 ubiquitination.

Signaling through tumor necrosis factor receptor 2 (TNF-R2) results in ubiquitination of TRAF2 by the E3 c-IAP1. In this report, we confirm that TRAF2 translocates to a Triton X-100 (TX)-insoluble compartment upon TNF-R2 engagement. Moreover, TRAF2 ubiquitination occurs in this compartment, from which TRAF2 is degraded in a proteasome-dependent manner. Confocal microscopy demonstrated that the TX-insoluble compartment is perinuclear and co-localizes with endoplasmic reticulum (ER) markers. The ER transmembrane Ubc6 bound to c-IAP1 and served as a cognate E2 for c-IAP1's E3 activity in vitro. Furthermore, Ubc6 co-localized with translocated TRAF2/c-IAP1 in the ER-associated compartment in vivo, and a catalytically inactive Ubc6 mutant inhibited TNF-alpha-induced, TNF-R2-dependent TRAF2 degradation. These results indicate that upon TNF-R2 signaling, translocation of TRAF2 and c-IAP1 to an ER-associated, Ubc6-containing perinuclear compartment is required for the ubiquitination of TRAF2 by c-IAP1. Therefore, the ER plays a key role in the TNF-R-mediated signal transduction cascade by acting as a site of assembly for E2/E3/substrate complexes.

Animals↗

PubMed2005

Biochemical characterization of the deafness-associated mitochondrial tRNASer(UCN) A7445G mutation in osteosarcoma cell cybrids.

The deafness-associated A7445G mutation in the precursor of mitochondrial tRNA(Ser(UCN)) has been identified in several pedigrees from different ethnic backgrounds. To determine the role of nuclear background in the biochemical manifestation associated with the A7445G mutation, we performed a biochemical characterization of this mutation using cybrids constructed by transferring mitochondria from lymphoblastoid cell lines derived from a New Zealand family into human osteosarcoma mtDNA-less (rho(0)) cells. Compared with three control cybrids, three cybrids derived from an affected matrilineal relative carrying the homoplasmic A7445G mutation exhibited approximately 38-57% decrease in the steady-state level of tRNA(Ser(UCN)), which is less reduced levels than in lymphoblastoid cells in the previous study. Furthermore, approximately 22% reduction in the level of aminoacylation of tRNA(Ser(UCN)) was observed in the mutant cybrid cells. Interestingly, approximately 60-63% decrease of steady-state level of ND6 gene, which belongs to the same precursor as that of tRNA(Ser(UCN)), in cybrid cell lines carrying the A7445G mutation, is more than that observed in lymphoblastoid cells. These observations strongly point out a mechanistic link between the processing defect of the tRNA(Ser(UCN)) precursor and decreased stability of ND6 mRNA precursor. These results also imply the influence of nuclear background on the biochemical phenotype associated with the A7445G mutation.

Cell Line↗

PubMed2005

Functional characterization of the mitochondrial 12S rRNA C1494T mutation associated with aminoglycoside-induced and non-syndromic hearing loss.

In this study, we report the biochemical characterization of the deafness-associated mitochondrial 12S rRNA C1494T mutation using 27 cybrid cell lines constructed by transferring mitochondria from 9 lymphoblastoid cell lines derived from a Chinese family into human mitochondrial DNA (mtDNA)-less (rho degrees) cells. Six cybrids derived from two asymptomatic members, and nine cybrids derived from three symptomatic members of the Chinese family carrying the C1494T mutation exhibited approximately 38 and 43% decrease in the rate of mitochondrial protein labeling, respectively, compared with twelve cybrids derived from four Chinese control individuals. These defects are apparently a primary contributor to significant reductions in the rate of overall respiratory capacity or the rate of malate/glutamate promoted respiration, or succinate/G3P-promoted respiration, or TMPD/ascorbate-promoted respiration in mutant cybrid cell lines derived from either symptomatic or asymptomatic individuals. Furthermore, the very significant/nearly identical increase in the ratio of doubling times in DMDM medium in the presence/absence of high concentration of paromomycin was observed in symptomatic or asymptomatic cybrid cell lines carrying the C1494T mutation as compared with the average rate in control cell lines. These observations provide the direct biochemical evidences that the C1494T mutation is a pathogenic mtDNA mutation associated with aminoglycoside-induced and non-syndromic hearing loss. In addition, these data provide the first biochemical evidence that nuclear background plays a critical role in the phenotypic manifestation of non-syndromic hearing loss and aminoglycoside toxicity associated with the C1494T mutation.

Cell Growth Processes↗

PubMed2005

Alcohol intoxication and sexual risk behaviors among rural-to-urban migrants in China.

BACKGROUND: The migrant population in China is at high risk for sexual risk behavior and alcohol intoxication. Information about the prevalence of alcohol intoxication and its association with sexual risk behavior among migrants is needed for designing effective intervention prevention programs for reduction in alcohol abuse and HIV infection. METHODS: Cross-sectional data were collected from 2153 sexually experienced young rural-to-urban migrants in Beijing and Nanjing, China, in 2002. RESULTS: Approximately one-third of the participants had been intoxicated with alcohol at least once during the previous month, with more males than females reporting intoxication (40.2% versus 23.7%, p<0.001). Compared to non-intoxicated participants, respondents with alcohol intoxication in previous 30 days reported more psychological problems, including higher depression scores, lower levels of satisfaction with life and work, and higher perception of peer involvement in risk behavior. Intoxicated respondents were more likely to engage in premarital sex than non-intoxicated respondents (76% versus 60.2%, p<0.001), have multiple sexual partners (13.4% versus 5.2%, p<0.001), purchase sex (12.6% versus 4.9%, p<0.001), and sell sex (10.1% versus 3.7%, p<0.001). However, there was no association between alcohol intoxication and inconsistent/non-use of condoms. Multivariate analysis controlling for depression, peer risk involvement, age, gender, and other socio-demographic variables indicated that alcohol intoxication was independently correlated with premarital sex, multiple sexual partners, and buying and selling sex. CONCLUSIONS: Compared to the general Chinese population, levels of intoxication were elevated among Chinese rural-to-urban migrants. Alcohol intoxication was associated with sexual risk behaviors. HIV/AIDS prevention and intervention efforts should include components of alcohol use/abuse prevention for an effective reduction of sexual risk among young rural-to-urban migrants in China.

Adolescent↗

PubMed2005

Cloning and characterization of mouse mTERF encoding a mitochondrial transcriptional termination factor.

We report here the identification and characterization of mouse mTERF encoding a mitochondrial transcription termination factor. A full-length mTERF cDNA has been isolated and the genomic organization of mTERF has been elucidated. The mouse mTERF gene containing two exons encodes a 380 residue protein with a strong homology to the mTERF-like proteins of human and other organisms, related to mitochondrial transcription termination. Northern blot analysis detected both 1.4 and 5.4kb transcripts. The mouse mTERF 1.4kb transcript agreeing with the size of cDNA is predominately expressed in heart and liver, but at extremely low level in other tissues. In addition, a approximately 5.4kb transcript likely resulting from the retention of intron appears to express abundantly in heart and skeletal muscle, but at very low level in other tissues. Furthermore, immunofluorescence analysis of NIH3T3 cells expressing mTERF-GFP fusion protein demonstrated that the mouse mTERF localizes in mitochondrion. These observations suggest that the mouse mTERF is an evolutionarily conserved mitochondrial transcription termination factor, thereby promoting the termination of transcription in mitochondrial RNA.

Amino Acid Sequence↗

PubMed2005

Gadolinium-enhanced MR imaging of epiphyseal and metaphyseal marrow in normal piglets.

The purpose of this study is to define the appearance of normal epiphyseal and metaphyseal marrow and normal changes of marrow due to fatty conversion on Gadolinium (Gd)-enhanced MR Imaging. Unenhanced and enhanced T1-weighted MR imaging were performed in proximal and distal femoral ends of 8 healthy piglets at the ages of 2, 4, 6 and 8 weeks, respectively. The changes with age in signal intensity and enhancement ratio of the epiphyseal and metaphyseal marrow with age were examined. The correlation of MRI characteristics with histological findings was studied. Our study showed that marrow of the metaphysis and of periphery of the 2nd ossification center were well vascularized hematopoietic marrow and had great enhancements. The enhancement ratio of metaphysis was greater than that of epiphyseal marrow and both enhancement ratios degraded gradually with age. The central regions of the epiphyseal ossification center and of the diaphysis were of fatty marrow and had little enhancement. It is concluded that on Gd-enhanced MR imaging the hematopoietic marrow of metaphysis and of periphery of the 2nd ossification center had greater enhancement than that of fatty marrow of central region of the 2nd ossification center. All of their enhancements decreased gradually with age.

Animals↗

PubMed2005

Epiphyseal and physeal cartilage: normal gadolinium-enhanced MR imaging.

To evaluate the normal appearance of epiphyseal and physeal cartilage on Gadolinium (Gd)-enhanced MR imaging. The appearance and enhancement ratios of 20 proximal and distal femoral epiphyses in 10 normal piglets were analyzed on Gd-enhanced MR images. The correlation of the MR imaging appearance with corresponding histological findings of immature epiphyses was examined. Our results showed that Gd-enhanced MRI could differentiate the differences in enhancement between physeal and epiphyseal cartilage and show vascular canals within the epiphyseal cartilage. Enhanced ratios in the physeal were greater than those in the epiphyseal cartilage (P < 0.005). It is concluded that Gd-enhanced MR imaging reveals epiphyseal vascular canals and shows difference in enhancement of physeal and epiphyseal cartilage.

Animals↗

PubMed2005

Influence of prior sexual risk experience on response to intervention targeting multiple risk behaviors among adolescents.

PURPOSE: To identify correlates of sexual risk variations among African-American adolescents, and to examine the influence of prior sexual experience on response to a HIV risk-reduction intervention. METHODS: Eight hundred seventeen African-American youth aged 13 to 16 years living in and around urban public housing in Baltimore were recruited to participate in a HIV risk-reduction intervention targeting multiple risk behaviors. An instrument designed to measure three levels of sexual risk ("abstinent," "protected sex" [having sex with a condom], and "unprotected sex" [having sex without a condom]) was administered at baseline, 6 months and 12 months postintervention. Multiple regression analyses were conducted to identify predictors of the degree of sexual risk using longitudinal data. Repeated measure analyses were conducted to assess behavioral changes over time among the three groups. RESULTS: Data confirmed the co-variation of sexual risk behavior and other problem behaviors among adolescents, cross-sectionally and longitudinally. After exposure to an 8-session risk-reduction intervention, youth engaging in the highest degree of sexual risk demonstrated the greatest reduction in both sexual risk and other risks. These improvements were seen at both 6 months and 12 months postintervention. Youth who were abstinent at baseline maintained the lowest levels in risk involvement throughout the study period when compared with sexually active youth. However, abstinent youth risk involvement significantly increased at 6 months and 12 months after baseline. Youth engaging in protected sex at baseline demonstrated a significant increase in non-condom use and a significant decrease in multiple risk involvement over time. CONCLUSIONS: Results support HIV risk-reduction intervention efforts that target multiple risk behaviors. Response of adolescents to the intervention is directly related to the sexual risk behavior at baseline. These data may suggest that the response to risk behavior intervention depends in part on the risk behavior profile of the population to which it is being applied.

Adolescent↗

PubMed2005

The complex business of adapting effective interventions to new populations: an urban to rural transfer.

PURPOSE: To assess the effectiveness of a relatively unaltered version of a sexual risk reduction intervention previously shown to be effective among urban youth, "Original Focus on Kids" (OFOK), compared with a version modified for West Virginia (WVFOK) and a control condition (training in environmental conservation), in altering protective sexual behaviors and perceptions among rural, Appalachian youth. SUBJECTS: Nine hundred ninety-nine youth aged 12 to 16 years from 12 rural counties in West Virginia. METHOD: Randomized, controlled, longitudinal trial of a theory-based prevention intervention. Outcomes were self-reported sexual behaviors and perceptions assessed at baseline, 3, 6, and 9 months postintervention. RESULTS: Both WVFOK and OFOK positively affected perceptions of abstinence but not behaviors. OFOK significantly enhanced some perceptions of condom use compared with both control youth and WVFOK youth, but again, not behaviors. CONCLUSIONS: Overall, neither version was as effective as FOK had been in the original urban setting. The less altered version (OFOK) was more effective, especially with regard to condom-use perceptions, in this new population and cultural setting than the more culturally altered version (WVFOK). In several of the implementation settings, neither version was delivered as intended by the researchers because of logistic issues. Although many of these changes were seemingly minor, such deviations may have significant impact on intervention effect.

Adolescent↗

PubMed2005

Substance use among rural adolescent virgins as a predictor of sexual initiation.

Longitudinal data from 746 virgins (310 males) aged 12 to 16 years were analyzed to assess the relationship between baseline substance use and sexual initiation 3, 6, and 9 months later. Compared to virgins with no substance use, virgins who had used three or more substances were three times more likely to initiate sex over the ensuing 9 months. The use of alcohol, tobacco, and marijuana and the use of more than three substances are highly specific for predicting sexual initiation.

Adolescent↗

PubMed2005

Perceptions regarding preventive sexual practices and communication with sexual partners among Chinese college students.

PURPOSE: To assess the relation between Chinese college students' perceptions and attitudes regarding preventive sexual behaviors, their sexual knowledge, and their use of protective sexual behaviors. METHODS: A subsample of 133 sexually active college students (18-25 years old) was obtained to identify factors related to protective sexual behaviors (e.g., knowledge of partner's sexual history, condom use). RESULTS: Seventy-five percent of the sexually active students were male. Significantly more females had discussed AIDS and sexually transmitted diseases (STDs) issues with their partners and had asked their partners about their sexual histories than males. Students endorsing the use of preventive behaviors were more likely to have discussed AIDS issues with their partners, used condoms, and known their partner's sexual history. CONCLUSIONS: Student perceptions about preventive behaviors have a significant impact on their knowledge of their sexual partners and their own sexual behaviors. These findings, as well as the presence of significant gender differences in perceptions and communications with their partners, have major implications for risk reduction programs.

Adolescent↗

PubMed2005

HIV-related risk factors associated with commercial sex among female migrants in China.

Data from 633 sexually experienced female migrants were analyzed to examine the sociodemographic and psychosocial factors and human immunodeficiency virus (HIV)-related behaviors associated with involvement in commercial sex. Six percent (40/633) of the participants reported having had sex for money. Compared with women who had not engaged in commercial sex, women who had sold sex were younger, less educated, and more likely to be unmarried. They were more likely to have engaged in HIV-related risk behaviors, such as becoming intoxicated with alcohol and using drugs. Among women engaged in commercial sex, only 28% of them consistently used condoms during the last three episodes of sexual intercourse. Women who had ever engaged in commercial sex demonstrated greater depressive symptoms than those without such as history (p < .01). Female migrants, especially those engaging in commercial sex, were vulnerable to HIV/sexually transmitted diseases (STDs). Sexual risk reduction and condom promotion are urgently needed among this population. Further studies are needed to examine the casual relationship between depression and HIV risk behaviors.

Adult↗