PubMed Health⌕ Search

Biomedical subjects

Bing Yu

Publications and source records attributed to Bing Yu.

At least 19 recordsLinked to original sources

Height variation independent of known genetic variants and health in later life: a cohort study.

BACKGROUND: Adult-attained height is associated with later-life health, but it reflects both genetic and nongenetic influences. The health implications of height variation not explained by known common height-associated genetic variants remain unclear. OBJECTIVES: This study aimed to examine associations of residual height (height variation independent of known genetic variants) with multiple disease incidence and all-cause mortality in later life. METHODS: In this cohort study of 407,366 adults of European ancestry (aged 40-70 y) in the United Kingdom Biobank (2006-2010), sex- and age-specific genetically predicted height was estimated from 9863 height-associated variants, adjusted for 30 principal components of ancestry. Residual height was calculated as the difference between observed and genetically predicted height. Plasma proteomics (2054 proteins; Olink Explore) were profiled. Deaths and 49 incident diseases were ascertained through national registries. Multivariable Cox models estimated associations of residual height and related proteins with disease incidence and mortality. RESULTS: Higher residual height [mean (standard deviation, SD), 0.0 (4.8)] was associated with more favorable self-reported preadulthood exposures (e.g., later birth years, no maternal smoking around birth, being breastfed as an infant, no adoption experience, and lower childhood adversity scores) and lower hazard ratios (HRs) of 32 out of 49 diseases (median follow-up = &#x223c;12.5 y). Using participants with residual height within &#xb1;0.5 SDs from the mean as reference, those with residual height < -2 SDs had higher adjusted HRs of mortality [1.61; 95% confidence interval (CI): 1.50, 1.72], multimorbidity (1.28; 95% CI: 1.12, 1.46), cardiovascular disease (1.45; 95% CI: 1.32, 1.60), psychiatric/neurological disease (1.38; 95% CI: 1.28, 1.48), and other disease categories (e.g., diabetes, digestive, and musculoskeletal diseases). In contrast, higher genetically predicted height was associated with a higher incidence of 19 diseases, including subtypes of cancer, non-atherosclerotic cardiovascular diseases, and musculoskeletal diseases, as well as higher all-cause mortality. We identified 806 plasma proteins related to inflammation, immune response, and autophagy via tumor necrosis factor, Nuclear factor-kappa B, phosphoinositide-3 kinase/protein kinase B, and Janus kinase/signal transducer and activator of transcription signaling pathways, which were associated with residual height and multiple diseases and mortality. CONCLUSIONS: Higher residual height is associated with lower disease incidence and mortality, with associations that are distinct from those for genetically predicted height.

Humans↗

Metabolomic Signatures of Inflammation in Chronic Kidney Disease.

RATIONALE & OBJECTIVE: Inflammation is associated with adverse kidney, cardiovascular, and mortality outcomes. Investigation of the metabolic milieu as it relates to inflammation may provide important insights into these disease processes. STUDY DESIGN: Prospective cohort. SETTING & PARTICIPANTS: African American Study of Kidney Disease and Hypertension (AASK), Atherosclerosis Risk in Communities (ARIC) study, and Boston Kidney Biopsy Cohort (BKBC) participants with available metabolomics and inflammatory protein data. PREDICTORS: Baseline blood levels of 718 metabolites. OUTCOMES: Baseline and longitudinal changes in blood levels of tumor necrosis factor receptors 1 and 2 (TNFR1, TNFR2), tumor necrosis factor-alpha (TNF-&#x3b1;), interferon-gamma (IFN-&#x3b3;), interleukins 6, 8, and 10 (IL-6, IL-8, IL-10), uromodulin (UMOD), and epidermal growth factor (EGF). ANALYTICAL APPROACH: Multivariable linear regression and linear mixed-effects models. RESULTS: Among 491 AASK participants (mean age 54 years; 37% women; mean glomerular filtration rate, 45 mL/min/1.73 m2), 367 cross-sectional associations between metabolites and inflammatory proteins were significant after correction for multiple comparisons. The direction of association was mostly positive for TNFR1 (97%), TNFR2 (97%), IL-8 (77%), and IL-10 (100%); negative for UMOD (80%) and EGF (97%); and variable for TNF-&#x237a;, IFN-&#x3b3;, and IL-6. Pathways were distinct for several inflammatory proteins (eg, tryptophan metabolism for TNFR2). Forty-five associations between metabolites and longitudinal change in inflammatory proteins were identified. Notable metabolites included tigylcarnitine and N 2,N 5-diacetylornithine, which were associated with 2-year increases in TNFR1 and/or TNFR2, and 1,5-anhydroglucitol, where lower levels were associated with decreases in UMOD. In ARIC (n = 3,773) and BKBC (n = 413), replication of cross-sectional associations was excellent for TNFR1 (ARIC 83%; BKBC 85%) and TNFR2 (ARIC 64%; BKBC 79%) but poor for IL-8 (ARIC 3%; BKBC 3%). LIMITATIONS: Metabolite data limited to baseline visit; potential for residual confounding. CONCLUSIONS: Using an untargeted approach, multiple metabolites were cross-sectionally and longitudinally associated with inflammatory proteins in persons with chronic kidney disease.

Chronic kidney disease↗

Proteomic Profiling of Pulmonary Function and Cardiovascular Disease Risk in the Atherosclerosis Risk in Communities Study.

BACKGROUND: Pulmonary function is linked to cardiovascular disease risk; however, the underlying mechanisms remain unclear. We aimed to identify protein biomarkers associated with pulmonary function and examine their impact on incident chronic obstructive pulmonary disease, coronary heart disease, heart failure, and all-cause mortality. METHODS: Data from White and Black Americans in the Atherosclerosis Risk in Communities study (visit 2: N=11&#x2009;354, mean age=57 years; visit 5: N=3517, mean age=75 years), a prospective cohort, were analyzed. Linear regression assessed associations between protein levels and pulmonary function measures, including forced expiratory volume in 1 second and forced vital capacity. The impact of the identified proteins on incident chronic obstructive pulmonary disease, coronary heart disease, heart failure, and mortality was estimated using logistic regression and Cox proportional hazards models. Pathway enrichment and Mendelian randomization explored underlying biological functions and causal effects. RESULTS: Of 4766 proteins analyzed, 364 were cross-sectionally associated with forced expiratory volume in 1 second (and forced vital capacity (false discovery rate<0.05). Ninety-four and 270 proteins had concordant positive and negative effects, respectively. Five pathways related to pulmonary and cardiac function were enriched. Of the 364 proteins, 112 were linked to all 4 outcomes, where 86 were associated with increased risk (odds ratio/hazard ratio [OR/HR], 1.05-1.42) and 26 with reduced risk (OR/HR, 0.69-0.96). Six proteins (STAT3 [signal transducer and activator of transcription 3], MIC-1 [growth differentiation factor 15], apoA-II [apolipoprotein A-II], TPST1 [protein-tyrosine sulfotransferase 1], integrin a1b1 [integrin alpha-I: beta-1 complex], and BLC [C-X-C motif chemokine 13]) showed potential inverse causal effects on with forced expiratory volume in 1 second and forced vital capacity, and integrin a1b1 demonstrated consistent inverse associations with chronic obstructive pulmonary disease, coronary heart disease, and heart failure risks. CONCLUSIONS: Proteins associated with pulmonary function may influence CVD risk. Six proteins, including integrin a1b1, represent promising targets for future interventions.

Aged↗

Large-Scale Proteomic Profiling of Incident Heart Failure and Its Subtypes in Older Adults.

BACKGROUND: Heart failure (HF) and its main subtypes, heart failure with preserved ejection fraction (HFpEF) and heart failure with reduced ejection fraction (HFrEF), impose an enormous health burden on elders. Assessment of the circulating proteome to illuminate pathogenesis could open new opportunities for treatment. METHODS: We conducted a plasma proteomics screen of incident HF and its subtypes in 2 older population-based cohorts, the CHS (Cardiovascular Health Study) and the AGES-RS (Aging, Gene/Environment Susceptibility-Reykjavik Study). The 2 studies used SomaLogic platforms, with 4404 aptamers in common. Multivariable Cox models were fit to evaluate individual-protein associations with HF, HFpEF, and HFrEF separately in each cohort, and study-specific associations were combined by fixed-effects meta-analysis. Replication was performed in the ARIC (Atherosclerosis Risk in Communities) cohort. Two-sample Mendelian randomization of HF and its subtypes, along with colocalization analysis, was performed to support causal inference. RESULTS: Among 8599 participants, 1590 experienced incident HF (536 HFpEF, 471 HFrEF). There were 119 proteins associated with HF, 15 proteins with HFpEF, and 11 proteins with HFrEF, at Bonferroni-corrected significance. Among these, 9 have never previously been identified for cardiovascular diseases, and another 61 represent new associations with incident HF or its subtypes. Of these 70 proteins, 55 of the 66 available replicated externally. Mendelian randomization analysis revealed 7 proteins genetically associated with HF at nominal significance; 2 were separately associated with HFpEF, and another 2 with HFrEF. Seven of these 9 proteins (NPDC1 [neural proliferation differentiation and control protein 1], APOF [apolipoprotein F], LMAN2 [lectin, mannose-binding 2], ADIPOQ [adiponectin], CD14 [cluster of differentiation 14], ARHGAP1 [Rho GTPase-activating protein 1], C9 [complement 9]) showed new, possibly causal associations, although we did not detect evidence for colocalization. CONCLUSIONS: In this large-scale proteomic study involving 3 longitudinal cohorts of older adults, we identified and replicated 55 novel protein markers of HF or its subtypes, and 7 new, possibly causal proteins. These proteins may enhance risk prediction, improve understanding of pathobiology, and help prioritize targets for therapeutic development of these foremost disorders in elders.

Humans↗

Genetic architecture and analysis practices of circulating metabolites in the NHLBI Trans-Omics for Precision Medicine Program.

Circulating metabolite levels partly reflect the state of human health and diseases and can be impacted by genetic determinants. Hundreds of loci associated with circulating metabolites have been identified; however, most findings focus on predominantly European ancestry or single-study analyses. Leveraging the rich metabolomics resources generated by the National Heart, Lung, and Blood Institute (NHLBI) Trans-Omics for Precision Medicine (TOPMed) Program, we harmonized and accessibly cataloged 1,729 circulating metabolites among 25,058 ancestrally diverse samples. From our comparison of multiple methods, we provided a set of reasonable strategies for outlier and imputation handling to process metabolite data and show that inverse normalization by study and half-minimum imputation provide mostly similar results for pooled or meta-analysis. Following the practical analysis framework, we further performed a genome-wide association analysis on 1,135 selected metabolites using whole-genome sequencing data from 16,359 individuals passing the quality-control filters and discovered 1,775 independent loci associated with 667 metabolites. Among 160 unreported locus-metabolite pairs, we identified associations with loci locating within previously implicated metabolite-associated genes, as well as associations with loci locating in genes such as GAB3 and VSIG4 (located on the X chromosome) that may play a role in metabolic regulation. In the sex-stratified analysis, we revealed 85 independent locus-metabolite pairs with evidence of sexual dimorphism, which were located in well-known metabolic genes such as FADS2, D2HGDH, SUGP1, and UGT2B17, strongly supporting the importance of exploring sex difference in the human metabolome. Taken together, our study depicted the genetic contribution to circulating metabolite levels, providing additional insight into the understanding of human health.

Humans↗

Steroid hormone biosynthesis and dietary related metabolites associated with excessive daytime sleepiness.

BACKGROUND: Excessive daytime sleepiness (EDS) is a complex sleep problem that affects approximately 33% of the United States population. Although EDS usually occurs in conjunction with insufficient sleep and other sleep and circadian disorders, recent studies have shown unique genetic markers and metabolic pathways underlying EDS. Here, we aimed to further elucidate the biological profile of EDS using large-scale single- and pathway-level metabolomics analyses. METHODS: Metabolomics data were available for 877 metabolites in 6071 individuals from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL). EDS was assessed using the Epworth Sleepiness Scale (ESS) questionnaire. We performed linear regression for each metabolite on the continuous ESS score, adjusting for demographic, lifestyle, and physiological confounders, and in sex specific groups. Subsequently, gaussian graphical modelling was performed coupled with pathway and enrichment analyses to generate a holistic interactive network of the metabolomic profile of EDS associations. FINDINGS: We identified seven metabolites belonging to steroids, sphingomyelin, and long-chain fatty acids sub-pathways in the primary model associated with EDS, and an additional three metabolites in the male-specific analysis. INTERPRETATION: Our findings indicate that an EDS metabolomic profile is characterised by endogenous and dietary metabolites within the steroid hormone biosynthesis pathway, with some pathways that differ by sex. These pathways may be useful for understanding the causes or consequences of EDS and related sleep disorders. FUNDING: Details regarding funding supporting this work and all studies involved are provided in the acknowledgements section.

Humans↗

Alterations in DNA Methylation, Proteomic, and Metabolomic Profiles in African Ancestry Populations with APOL1 Risk Alleles.

KEY POINTS: We aimed to elucidate potential methylation, proteomic, and metabolomic mechanisms by which APOL1 variants may be linked to kidney disease. We report distinct methylation profiling between APOL1 risk allele carriers and noncarriers, many near APOL gene family. We report higher APOL1 protein and lower C18:1 cholesteryl ester in two risk allele carriers. BACKGROUND: The APOL1 high-risk haplotype has been associated with CKD and the deterioration of kidney function, particularly in populations with West African ancestry. However, the mechanisms by which APOL1 risk variants increase the risk for kidney disease and its progression have not been fully elucidated. METHODS: We compared methylation (N=3191; 715 [22%] carriers), proteomic (N=1240; 169 [14%] carriers), and metabolomic (N=6309; 674 [11%] carriers) profiles in African and Hispanic/Latino carriers of two APOL1 high-risk alleles (G1/G1, G2/G2, G1/G2) and noncarriers (G0/G0), excluding heterozygotes (G0/G1, G0/G2), from the Population Architecture using Genomics and Epidemiology Consortium and UK Biobank. In each study, the associations between the APOL1 high-risk haplotype and up to 722,719 cytosine-phosphate-guanine (CpG) sites, 2923 proteins, or 836 metabolites were estimated using covariate-adjusted linear regression models, followed by fixed-effects sample size&#x2013;weighted meta-analyses. RESULTS: Significant associations were observed between APOL1 high-risk haplotype and methylation at 52 CpG sites, with 48 located on chromosome 22 and 18 in the vicinity of APOL1&#x2013;4 and MYH9. All significant CpG sites near APOL2 were hypomethylated, whereas those near APOL3 and APOL4 were hypermethylated. APOL1-associated CpG sites were also identified in genes involved in ion transport and mitochondrial stress pathways. Sensitivity analyses indicated consistent yet attenuated effects among heterozygotes, supporting an additive effect of APOL1 risk alleles. Further analyses of the 52 CpG sites identified two near APOL4 exhibiting G1-specific effects, eight associated with CKD but none with eGFR, and three showing heterogeneity by CKD status. In addition, carrying two APOL1 risk alleles was associated with higher plasma APOL1 protein (&#x3b2;=1.12, PFDR = 2.26e-70) and lower C18:1 cholesteryl ester metabolite (Z=&#x2212;4.50, PFDR = 4.83e-3). CONCLUSIONS: Our results demonstrate differential methylation, proteomic, and metabolomic profiles associated with APOL1 high-risk haplotypes.

APOL1↗

Erythritol, Erythronate, and Cardiovascular Outcomes in Older&#xa0;Adults&#xa0;in the ARIC Study.

BACKGROUND: Circulating erythritol, an endogenously produced metabolite and an artificial sweetener, is associated with cardiovascular outcomes. OBJECTIVES: The authors assessed associations of erythritol and its downstream metabolite, erythronate, with cardiovascular risk factors and events in older adults in the ARIC (Atherosclerosis Risk In Communities) study (visit 5, 2011-2013). METHODS: We included 4,006 participants without prevalent cardiovascular disease and with metabolomic profiling. Erythritol and erythronate were measured by mass spectrometry. We analyzed associations of log-transformed erythritol and erythronate with cardiovascular risk factors and events using Cox proportional hazard models. RESULTS: Participants in the highest tertiles of erythritol or erythronate were older, more likely to have diabetes, hypertension, hyperlipidemia, or microalbuminuria, and had higher body mass index and cardiac biomarkers and lower estimated glomerular filtration rate (P&#xa0;<&#xa0;0.001). Over median follow-up of 8.41 (7.62, 8.93) years, higher erythritol and erythronate concentrations were significantly associated with heart failure (HF) hospitalization, HF with preserved ejection fraction, cardiovascular death, and total mortality after adjustment for demographics and traditional cardiovascular risk factors. Erythronate was additionally significantly associated with coronary heart disease (HR: 1.30 [95% CI: 1.04-1.61], P&#xa0;=&#xa0;0.02), stroke (1.40 [95% CI: 1.08-1.83], P&#xa0;=&#xa0;0.012), and HF with reduced ejection fraction (1.38 [95% CI: 1.09-1.74], P&#xa0;=&#xa0;0.007). Diabetes status did not modify any of these associations (P for interaction >0.20). CONCLUSIONS: Circulating erythritol and erythronate levels are markers of cardiometabolic health and cardiovascular outcomes in an older adult population. In particular, erythronate is associated with all cardiovascular outcomes assessed. Future studies should assess the role of erythronate and its related pathways in cardiovascular disease.

artificial sweetener↗

Cardiovascular Risk Factors and Genetic Risk in Transthyretin V142I Carriers.

BACKGROUND: Nearly 3% to 4% of Black individuals in the United States carry the transthyretin V142I variant, which increases their risk of heart failure. However, the role of cardiovascular (CV) risk factors (RFs) in influencing the risk of clinical outcomes among V142I variant carriers is unknown. OBJECTIVES: This study aimed to assess the impact of CV RFs on the risk of heart failure in V142I carriers. METHODS: This study included self-identified Black individuals without prevalent heart failure from 6 TOPMed (Trans-Omics for Precision Medicine) cohorts, the REGARDS (Reasons for Geographic And Racial Differences in Stroke) study, and the All of Us Research Program. The cohort was stratified based on the V142I genotype and the number of CV RFs (hypertension, diabetes, obesity, and hypercholesterolemia). Adjusted Cox models were used to assess the association of heart failure with the V142I genotype and CV RF profile, taking noncarriers with a favorable CV RF profile as reference. RESULTS: The cross-sectional analysis, including 1,625 V142I carriers among 48,365 Black individuals, found that the prevalence of CV RFs did not vary by V142I carrier status. In the longitudinal analysis, there were 587 (3.2%) V142I carriers among 18,407 Black individuals (median age: 60 years [Q1-Q3: 52-68 years], 63.0% female). Among carriers, the heart failure risk was attenuated with a favorable (0 or 1 RF) CV RF profile (adjusted HR: 2.26; 95%&#xa0;CI: 1.58-3.23) compared with an unfavorable (3 or 4 RFs) CV RF profile (adjusted HR: 4.14; 95%&#xa0;CI: 2.79-6.14). CONCLUSIONS: A favorable CV RF profile lowers but does not abrogate V142I variant-associated heart failure risk. This study highlights the importance of having a favorable CV RF profile among V142I carriers for risk reduction of heart failure.

Aged↗

A gene-environment study of the paraoxonase 1 gene and pesticides in amyotrophic lateral sclerosis.

Sporadic amyotrophic lateral sclerosis (SALS) causes progressive muscle weakness because of the loss of motor neurons. SALS has been associated with exposure to environmental toxins, including pesticides and chemical warfare agents, many of which are organophosphates. The enzyme paraoxonase 1 (PON1) detoxifies organophosphates and the efficacy of this enzyme varies with polymorphisms in the PON1 gene. To determine if an impaired ability to break down organophosphates underlies some cases of SALS, we compared the frequencies of PON1 polymorphisms in SALS patients and controls and investigated gene-environment interactions with self-reported pesticide/herbicide exposure. The PON1 coding polymorphisms L55M, Q192R and I102V, and the promoter polymorphisms -909c>g, -832g>a, -162g>a and -108c>t, were genotyped in 143 SALS patients and 143 matched controls. Statistical comparisons were carried out at allele, genotype and haplotype levels. The PON1 promoter allele -108t, which reduces PON1 expression, was strongly associated with SALS. Overall, promoter haplotypes that decrease PON1 expression were associated with SALS, whereas haplotypes that increase expression were associated with controls. Coding polymorphisms did not correlate with SALS. Gene-environment interactions were identified at the allele level for some promoter SNPs and pesticide/herbicide exposure, but not at the genotype or haplotype level. In conclusion, some PON1 promoter polymorphisms may predispose to SALS, possibly by making motor neurons more susceptible to organophosphate-containing toxins.

Aged↗

Are metallothionein genes silenced in ALS?

Sporadic amyotrophic lateral sclerosis (SALS) results from the death of motor neurons in the brain and spinal cord. Environmental exposure to heavy metals has been implicated in SALS and impaired detoxification of these metals may cause susceptibility to the disease. The metallothionein (MT) family of proteins are the primary detoxification mechanism for heavy metals and MT-Ia and MT-IIa are the most common human isoforms. Inappropriate methylation at the promoters of these genes could lead to silencing of transcription and reduce the availability of MTs. We therefore measured the level of methylation in the promoters of MT-Ia and MT-IIa in 25 leukocyte and six brain DNA samples from SALS patients and compared these with controls. No promoter methylation was evident in any SALS or control samples. In conclusion, it is unlikely that methylation at these gene promoters is a common cause of SALS.

Amyotrophic Lateral Sclerosis↗

Silencing stathmin gene expression by survivin promoter-driven siRNA vector to reverse malignant phenotype of tumor cells.

Stathmin gene overexpression has been shown to play an important role in maintenance of malignant phenotype in tumor cells, and the blocking efficacy and tumor specificity of this target has been concerned in clinical trails. In this report, we designed survivin promoter-driven siRNA eukaryotic expression vector that expressed the small interfering RNA targeting stathmin gene to selectively knock down the stathmin gene expression in two different kinds of tumor cell lines while sparing normal cell lines. The therapeutic potential of this recombinant vector was tested in human cervical cancer Hela cells and osteosarcoma SSOP-9607 cells, and in human umbilical vein endothelial cell line ECV304 cells as control. The siRNA vector- transfected Hela cells and SSOP-9607 cells revealed marked inhibition of stathmin expression and a dramatic growth inhibition comparing with ECV304 cells, parental-vector transfected cells and untransfected cells. Cell cycle analysis of siRNA vector transfected tumor cells by Flow Cytometry showed G(2)/M phase block, while morphologic analysis by TURNEL staining method showed marked increase of apoptosis. Our study indicates that survivin gene promoter-driven stathmin siRNA expression vector may have potential use in tumor gene therapy with targeted tumor gene silencing effect.

Apoptosis↗

Kinematics and electromyography of landing preparation in vertical stop-jump: risks for noncontact anterior cruciate ligament injury.

BACKGROUND: Biomechanical analysis of stop-jump tasks has demonstrated gender differences during landing and a potential increase in risk of noncontact anterior cruciate ligament injury for female athletes. Analysis of landing preparation could advance our understanding of neuromuscular control in movement patterns and be applied to the development of prevention strategies for noncontact anterior cruciate ligament injury. HYPOTHESIS: There are differences in the lower extremity joint angles and electromyography of male and female recreational athletes during the landing preparation of a stop-jump task. STUDY DESIGN: Controlled laboratory study. METHODS: Three-dimensional videographic and electromyographic data were collected for 36 recreational athletes (17 men and 19 women) performing vertical stop-jump tasks. Knee and hip angular motion patterns were determined during the flight phase before landing. RESULTS: Knee and hip motion patterns and quadriceps and hamstring activation patterns exhibited significant gender differences. Female subjects generally exhibited decreased knee flexion (P = .001), hip flexion (P = .001), hip abduction (P = .001), and hip external rotation (P = .03); increased knee internal rotation (P = .001); and increased quadriceps activation (P = .001) compared with male subjects. Female subjects also exhibited increased hamstring activation before landing but a trend of decreased hamstring activation after landing compared with male subjects (P = .001). CONCLUSION: Lower extremity motion patterns during landing of the stop-jump task are preprogrammed before landing. Female subjects prepared for landing with decreased hip and knee flexion at landing, increased quadriceps activation, and decreased hamstring activation, which may result in increased anterior cruciate ligament loading during the landing of the stop-jump task and the risk for noncontact ACL injury.

Adult↗

Cytotoxicity of HSVtk and hrTNF-alpha fusion genes with IRES in treatment of gastric cancer.

The efficacy of the suicide gene therapy by using the herpes simplex virus thymidine kinase/ganciclovir (HSVtk/GCV) system for the treatment of cancer is limited because of the insufficient gene transfer and the low killing activity. To enhance the anti-tumor activity, we probed into whether recombinant retroviral expression vector PLXSN expressing both HSVtk and TNF-alpha genes could potentiate the destruction of SGC7901. The pL(tk-TNF-alpha)SN harboring HSVtk and TNF-alpha genes in sequence was constructed with a bicistronic unit including the internal ribosomal entry site, the recombinant retroviruses were transferred into SGC7901 cells by lipofectamine, and pEGFP and Western blot analysis were used to detect the expression of fusion genes in transfected SGC7901 cells, and then apoptosis of the transfected cells were detected by using the TdT-mediated dUTP nick end labeling, flow cytometric analysis and transmission electron microscopy. In vitro study, the transfected gastric cancer cells were maintained in the GCV-contained medium, to assay the cell killing effect and bystander effect. In vivo experiments, retroviral serum plasmids were transfected into tumor-bearing nude mice, to observe the changes of tumor volumes and survival of the mice. In vitro there was no significant difference of cell survival rate between the three groups. However, in vivo results showed that tk/GCV, tk-TNF-alpha/GCV and TNF-alpha could inhibit the tumor growth, and the obvious anti-tumor effect was shown in tk-TNF-alpha/GCV group, and TNF-alpha obviously enhanced the anti-tumor effect in vivo. The pathologic examination showed necrosis of the cancer in the treated groups.

Animals↗

Determination of tobacco-specific N-nitrosamines in rabbit serum by capillary zone electrophoresis and capillary electrophoresis-electrospray ionization-mass spectrometry with solid-phase extraction.

In this paper, we propose a new strategy for separation and determination of tobacco-specific N-nitrosamines (TSNAs), a group of strong carcinogens found only in tobacco products, by using CZE and CE-MS associated with SPE. Six TSNAs: N'-nitrosonornicotine, N'-nitrosoanatabine, N'-nitrosoanabasine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol, and 4-(methylnitrosamino)-4-(3-pyridyl)-1-butanol were simultaneously separated by either of two CZE methods, one of which worked with ammonium formate buffer (pH 2.5) and another with citrate buffer (pH 2.4), as well as a CE-MS method. The CZE conditions including pH and concentration of running buffer, capillary length, applied voltage, and capillary temperature were systematically optimized. For CE-MS method, an optimized sheath liquid consisted of methanol-water was used at a flow rate of 10 muL/min. With SPE procedure, our proposed CE-MS method was successfully applied to determine TSNAs after 15 min metabolism in rabbits. A comparison study between CZE and CE-MS methods for quantitative purposes was carried out, showing that both methods provided similar separation efficiency, selectivity, repeatability, linearity, and recovery. However, CE-MS method was better suited for the analysis of TSNAs in complicated biological samples for its sensitivity and extra information on molecular structure. Having good accordance with our previous work by using LC-MS, the new CE-MS method is expected to be an alternative to the LC-MS method and applied to study the metabolism of TSNAs.

Animals↗

The unique expression profile of the androgen receptor gene in a rat model of neonatal cardiac hypertrophy.

UNLABELLED: Gender can influence many cardiovascular events, including cardiac hypertrophy. The presence of and dynamic changes involving androgen receptor (AR) gene expression are important confirmatory findings for androgen modulation in the pathogenesis of cardiac hypertrophy. AIMS: To determine AR expression profile during neonatal hypertrophy and its regression process using a rat model. METHODS: Relative mRNA levels of the AR gene were quantified at postnatal days 1, 7, 14, 21 and 28 using real time PCR. RESULTS: A significant 10.6-fold decrease in AR transcription levels was observed at birth in neonates with cardiac hypertrophy (p < 0.05). Our analysis also showed a significant increase in AR mRNA levels at day 28, corresponding with regression of cardiac hypertrophy. DISCUSSION: The AR gene demonstrated a noteworthy trend in its expression pattern. The initial down-regulation was most likely the result of increased testosterone levels induced by hyperinsulinaemia and hypoglycaemia, which were present in neonates from diabetic mothers during pregnancy. The paradoxical increase in AR at day 28 suggested a potential long term-effect of the in utero diabetic environment.

Animals↗

SRp54 (SFRS11), a regulator for tau exon 10 alternative splicing identified by an expression cloning strategy.

The tau gene encodes a microtubule-associated protein that is critical for neuronal survival and function. Splicing defects in the human tau gene lead to frontotemporal dementia with Parkinsonism linked to chromosome 17 (FTDP-17), an autosomal dominant neurodegenerative disorder. Genetic mutations associated with FTDP-17 often affect tau exon 10 alternative splicing. To investigate mechanisms regulating tau exon 10 alternative splicing, we have developed a green fluorescent protein reporter for tau exon 10 skipping and an expression cloning strategy to identify splicing regulators. A role for SRp54 (also named SFRS11) as a tau exon 10 splicing repressor has been uncovered using this strategy. The overexpression of SRp54 suppresses tau exon 10 inclusion. RNA interference-mediated knock-down of SRp54 increases exon 10 inclusion. SRp54 interacts with a purine-rich element in exon 10 and antagonizes Tra2beta, an SR-domain-containing protein that enhances exon 10 inclusion. Deletion of this exonic element eliminates the activity of SRp54 in suppressing exon 10 inclusion. Our data support a role of SRp54 in regulating tau exon 10 splicing. These experiments also establish a generally useful approach for identifying trans-acting regulators of alternative splicing by expression cloning.

Alternative Splicing↗

Understanding and preventing noncontact anterior cruciate ligament injuries: a review of the Hunt Valley II meeting, January 2005.

The incidence of noncontact anterior cruciate ligament injuries in young to middle-aged athletes remains high. Despite early diagnosis and appropriate operative and nonoperative treatments, posttraumatic degenerative arthritis may develop. In a meeting in Atlanta, Georgia (January 2005), sponsored by the American Orthopaedic Society for Sports Medicine, a group of physicians, physical therapists, athletic trainers, biomechanists, epidemiologists, and other scientists interested in this area of research met to review current knowledge on risk factors associated with noncontact anterior cruciate ligament injuries, anterior cruciate ligament injury biomechanics, and existing anterior cruciate ligament prevention programs. This article reports on the presentations, discussions, and recommendations of this group.

Anterior Cruciate Ligament↗