Trang Nguyen - Academia.edu (original) (raw)

Papers by Trang Nguyen

Cell calcium, Jan 28, 2015

Live cell imaging has revealed that calcium ions (Ca(2+)) pass in and out of many cellular organe... more Live cell imaging has revealed that calcium ions (Ca(2+)) pass in and out of many cellular organelles. However, technical hurdles have limited measurements of Ca(2+) in acidic organelles, such as endosomes. Although evidence hints that endosomes play a role in Ca(2+) signaling, direct measurements within endosomal lumina represent one of the final frontiers in organelle imaging. To measure Ca(2+) in a TiVAMP-positive endosome sub-population, the pH-resistant ratiometric Ca(2+) biosensor GEM-GECO1 and the ratiometric pH biosensor mKeima were used. A positive correlation between acidic endosomal pH and higher Ca(2+) was observed within these Rab5a- and Rab7-positive compartments. Ca(2+) concentration in most endosomes was estimated to be below 2μM, lower than Ca(2+) levels in several other intracellular stores, indicating that endosomes may take up Ca(2+) during physiological stimulation. Indeed, endosomes accumulated Ca(2+) during glucose-stimulation, a condition where endosomal pH did not change. Our biosensors permitted the first measurements revealing a role for endosomes in cellular Ca(2+) homeostasis during physiological stimulation.

Asian-Australasian journal of animal sciences, 2015

Castration induces the accumulation of body fat and deposition of intramuscular fat in Korean cat... more Castration induces the accumulation of body fat and deposition of intramuscular fat in Korean cattle, resulting in improved beef quality. However, little is known about the metabolic adaptations in the liver following castration. To understand changes in lipid metabolism following castration, hepatic expression levels of lipid metabolism genes were compared between Korean bulls and steers. Steers had higher (p<0.001) hepatic lipids contents and higher (p<0.01) mRNA levels of lipogenic acetyl-CoA carboxylase. This differential gene expression may, in part, contribute to increased hepatic lipid content following the castration of bulls. However, we found no differences in the hepatic expression levels of genes related to triglyceride synthesis (mitochondrial glycerol-3-phosphate acyltransferase, diacylglycerol O-acyltransferase 1 and 2) and fatty acid (FA) oxidation (carnitine palmitoyltransferase 1A, C-4 to C-12 straight chain acyl-CoA dehydrogenase, very long chain acyl-CoA dehydrogenase) between bulls and steers. No differences in gene expression for very-low-density lipoprotein (VLDL) secretion, including apolipoprotein B mRNA and microsomal triglyceride transfer protein (MTTP) protein, were observed in the liver although MTTP mRNA levels were higher in steers compared to bulls. In conclusion, FA synthesis may contribute to increased hepatic lipid deposition in steers following castration. However, hepatic lipid metabolism, including triglyceride synthesis, FA oxidation, and VLDL secretion, was not significantly altered by castration. Our results suggest that hepatic lipid metabolism does not significantly contribute to increased body fat deposition in steers following castration.

Archives of surgery (Chicago, Ill. : 1960), 2010

Clinical journal of the American Society of Nephrology : CJASN, 2011

Background and objectives Insulin has several physiologic actions that include stimulation of cel... more Background and objectives Insulin has several physiologic actions that include stimulation of cellular glucose and potassium uptake. The ability of insulin to induce glucose uptake by cells is impaired in type 2 diabetes mellitus, but whether potassium uptake is similarly impaired is not known. This study examines whether the cellular uptake of these molecules is regulated in concert or independently.

Neurological Research, 2011

Stereotactic radiosurgery is a modern addition to the armamentarium of treatment options for intr... more Stereotactic radiosurgery is a modern addition to the armamentarium of treatment options for intracranial and extracranial lesions. It is increasingly being used as an adjuvant to surgery, conventional radiation therapy, and chemotherapy as well as being used as primary treatment. Since the introduction of the Gamma Knife (Elekta, Stockholm, Sweden) system, many more stereotactic radiosurgery machines have become available. The objective of this review is to compare and contrast the various currently available stereotactic radiosurgery platforms.

Infection and Drug Resistance, 2011

The effectiveness of pandemic vaccine campaigns such as the H1N1 vaccine rollout is dependent on ... more The effectiveness of pandemic vaccine campaigns such as the H1N1 vaccine rollout is dependent on both the vaccines' effectiveness and the general public's willingness to be vaccinated. It is therefore critical to understand the factors that influence the decision of members of the public whether to get vaccinated with new, emergently released vaccines. A systematic review of English language quantitative surveys was conducted to identify consistent predictors of the decision to accept or decline any (pre)pandemic vaccine, including the H1N1 influenza A vaccine. A total of ten studies were included in this review and all pertained to the 2009 H1N1 influenza A pandemic.…

Chlamydia prevalence varies regionally but is highest in the South, which could be the result of ... more Chlamydia prevalence varies regionally but is highest in the South, which could be the result of regional differences in testing behavior. We describe the national and regional prevalence of self-reported chlamydial infection (Ct) testing and examine how financial resources might be associated with Ct testing. We conducted a cross-sectional analysis of data from 12,334 sexually experienced young adults who participated in wave III of the National Longitudinal Study of Adolescent Health (2001-2002). We estimated the prevalence of Ct testing by region and gender, and calculated prevalence odds ratios for the relationship between income or insurance status and Ct testing. Among women, Ct testing in the past year was low (27.3%; 95% CI, 25.5-29.2) and lowest in the South (24.8%). Compared with publicly insured females, privately insured (OR, 0.72; 95% CI, 0.57-0.92) and uninsured females (OR, 0.63; 95% CI, 0.48-0.88) were less likely to report testing. Young women with low income were more likely to report testing than those with a higher income (OR, 1.36; 95% CI, 1.12-1.66). Men reported similar testing patterns. The South has the highest chlamydia prevalence and the lowest levels of Ct testing in the United States. Reducing infection prevalence and regional disparities in the burden of this infection requires region-focused funding and innovative strategies to increase testing and treatment programs.

Journal of safety …, 2003

Outcome measures for safety training effectiveness research often do not include measures such as... more Outcome measures for safety training effectiveness research often do not include measures such as occupational injury experience. Effectiveness mediators also receive sparse attention. A new safety training curriculum was delivered to workers in a stratified random sample of food service facilities across three companies. A similar group of facilities received usual training. We collected post-test measures of demographic variables, safety knowledge, perceptions of transfer of training climate, and workers' compensation claim data for one year after the initial training activities. Knowledge test scores were apparently higher in the new-training units than in the usual-training units. Some demographic variables were inconsistently associated with these differences. Evidence for reduction of the injury rate associated with the new training was observed from two companies but only approached significance for one company. A second company revealed a similar but non-significant trend. Knowledge scores were not significantly associated with lower injury rates. We found evidence that safety training increases knowledge and reduces injuries. We found almost no evidence of effects of training effectiveness mediators, including no relationship between safety knowledge and injury experience. Methodological issues related to conducting a large study may have influenced these results. Although safety training leads to greater knowledge and, in some cases, reduced occupational injuries, the influence of mediating variables remains to be fully explained.

Public Health Reports, 2003

As the HIV epidemic has changed nationally, the parallel change in the Southern states has been a... more As the HIV epidemic has changed nationally, the parallel change in the Southern states has been a disproportionate increase in HIV infection among people of color and among women. Due to the limited and disjointed health care and social service resources in rural Southern regions, already marginalized groups have difficulty in accessing appropriate care and services to address their HIV infection seamlessly and with continuity. To ameliorate the limitations in the health care infrastructure, the North Carolina Services Integration Project collaborated with North Carolina medical and social service providers and state agencies to create a sustainable and replicable model of integrated care for HIV-positive, geographically dispersed residents.

Vaccine, 2006

We investigated effects of low titer (Lo) circulating MatAb on protection and immunogenicity of a... more We investigated effects of low titer (Lo) circulating MatAb on protection and immunogenicity of attenuated (Att) human rotavirus (HRV) priming and 2/6-virus-like particle (VLP)-immunostimulating complex (ISCOM) boosting (AttHRV/VLP) or VLP-ISCOM alone vaccines. LoMatAb had both enhancing and suppressing effects on B cell responses, depending on tissue, antibody isotype and vaccine. Differential effects of LoMatAb on IgA responses in different tissues suggest that LoMatAb did not suppress induction of IgA effector and memory B cells but impaired homing of these cells to secondary lymphoid or effector tissues, reducing IgA antibody secreting cells and antibodies at these sites. The AttHRV/VLP vaccine partially overcame LoMatAb suppression, conferred moderate protection against virulent HRV (as measured by reduced viral shedding and diarrhea) and represents a new candidate for rotavirus vaccines for both humans and animals.

Clinical and Vaccine …, 2004

A sequential mucosal prime-boost vaccine regimen of oral attenuated (Att) human rotavirus (HRV) p... more A sequential mucosal prime-boost vaccine regimen of oral attenuated (Att) human rotavirus (HRV) priming followed by intranasal (i.n.) boosting with rotavirus protein VP2 and VP6 rotavirus-like particles (2/6-VLPs) has previously been shown to be effective for induction of intestinal antibody-secreting cell (ASC) responses and protection in gnotobiotic pigs. Because serum or fecal antibody titers, but not intestinal ASC responses, can be used as potential markers of protective immunity in clinical vaccine trials, we determined the serum and intestinal antibody responses to this prime-boost rotavirus vaccine regimen and the correlations with protection. Gnotobiotic pigs were vaccinated with one of the two sequential vaccines: AttHRV orally preceding 2/6-VLP (VLP2x) vaccination (AttHRV/VLP2x) or following VLP2x vaccination (VLP2x/AttHRV) given i.n. with a mutant Escherichia coli heat-labile toxin (mLT) as adjuvant. These vaccines were also compared with three i.n. doses of VLP+mLT (VLP3x) and one and three oral doses of AttHRV (AttHRV1x and AttHRV3x, respectively). Before challenge all pigs in the AttHRV/VLP2x group seroconverted to positivity for serum immunoglobulin A (IgA) antibodies. The pigs in this group also had significantly higher (P < 0.05) intestinal IgA antibody titers pre- and postchallenge and IgG antibody titers postchallenge compared to those in the other groups. Statistical analyses of the correlations between serum IgM, IgA, IgG, and virus-neutralizing antibody titers and protection demonstrated that each of these was an indicator of protective immunity induced by the AttHRV3x and the AttHRV/VLP2x regimens. However, only IgA and not IgM or IgG antibody titers in serum were highly correlated (R2 = 0.89; P < 0.001) with the corresponding isotype antibody (IgA) titers in the intestines among all…

Veterinary immunology …, 2007

Maternal cytokines may play instructive roles in development of the neonatal immune system. Howev... more Maternal cytokines may play instructive roles in development of the neonatal immune system. However, cytokines in colostrum and milk and their transfer from mothers to neonates have not been well documented, except for TGF-b. Swine provide a unique model to study lactogenic cytokines because the sow's impermeable placenta prohibits transplacental passage. We investigated IL-6 and TNF-a (pro-inflammatory), IFN-g and IL-12 (Th1), IL-10 and IL-4 (Th2) and TGF-b1 (Th3) concentrations in sow serum and colostrum/milk and serum of their suckling and weaned piglets and in age-matched colostrum-deprived gnotobiotic piglets. All cytokines were detected in colostrum/milk and correlated with concentrations in sow serum except for mammary-derived TNF-a and TGF-b1. Detection of IL-12 and TGF-b1 in pre-suckling and colostrum-deprived gnotobiotic piglet serum suggests constitutive production: other cytokines were undetectable confirming absence of transplacental transfer. Peak median cytokine concentrations in suckling piglet serum occurred at post-partum days 1-2 (IL-4 > IL-6 > IFN-g > IL-10). The effects in vitro of physiologically relevant concentrations of the two predominant lactogenic cytokines (TGF-b1 and IL-4) on porcine naive B cell responses to lipopolysaccharide (LPS) and rotavirus (RV) were investigated. High (10 ng/ml) TGF-b1 suppressed immunoglobulin secreting cell responses to LPS and rotavirus; low concentrations (0.1 ng/ml) promoted isotype switching to IgA antibody. Interleukin-4 induced inverse dose-dependent (0.1 ng > 10 ng/ml) isotype switching to IgA and enhanced IgM secreting cell responses to LPS and rotavirus. In summary, we documented the transfer and persistence of maternal cytokines from colostrum/milk to neonates and their potential role in Th-2 biased IgA responses and reduced immunologic responsiveness of neonates. #

Clinical and vaccine …, 2006

Gnotobiotic pigs were injected intraperitoneally at birth with pooled serum from sows hyperimmuni... more Gnotobiotic pigs were injected intraperitoneally at birth with pooled serum from sows hyperimmunized with human rotavirus (HRV); control pigs received no sow serum. Pigs with or without MatAbs received either sequential attenuated HRV (AttHRV) oral priming and intranasal boosting with VP2/VP6 virus-like particle (VLP)-immunostimulating complex (ISCOM) (AttHRV/VLP) or intranasal VLP-ISCOM prime/boost (VLP) vaccines at 3 to 5 days of age. Subsets of pigs were challenged at 28 or 42 days postinoculation with virulent Wa HRV to assess protection.

JAIDS Journal of …, 2005

Background: Approximately 16 million people are enrolled in institutions of higher learning in th... more Background: Approximately 16 million people are enrolled in institutions of higher learning in the United States. However, college students have not been perceived as at high risk for HIV infection. In early 2003, acute HIV infection was diagnosed in 2 men attending college in North Carolina. We describe an epidemiologic investigation of newly diagnosed HIV infection in men attending college in North Carolina. Methods: We reviewed state surveillance records examining new HIV diagnoses in men 18-30 years old between January 1, 2000 and December 31, 2003, living in 69 North Carolina counties. Risk behavior and demographic information for HIV-infected men enrolled in college were compared with HIV-infected male nonenrollees.

Background: The emerging epidemic of overweight/obesity in adolescents in Ho Chi Minh City, Vietn... more Background: The emerging epidemic of overweight/obesity in adolescents in Ho Chi Minh City, Vietnam underlines the importance of studying the metabolic syndrome in Vietnamese adolescents who are becoming progressively more inactive. No study in Vietnam has examined the association of metabolic syndrome with moderate to vigorous physical activity (PA) levels among adolescents. We aimed to examine this association in a sample of urban adolescents from Ho Chi Minh City. Methods: A cross-sectional assessment was conducted in 2007 on a representative sample of 693 high-school students from urban districts in Ho Chi Minh City. Metabolic syndrome was defined according to the International Diabetes Federation criteria and physical activity was measured with Actigraph accelerometers. The association between physical activity and metabolic syndrome was assessed by using multiple logistic regression models.

This study explores key antecedents and an outcome of relationship value between manufacturers an... more This study explores key antecedents and an outcome of relationship value between manufacturers and distributors in the tile industry in a transition market -Vietnam. Using a sample of 317 distributors in the South of Vietnam, we found that relationship value is a key factor that drives the performance of distributors. In addition, product quality, information services, and delivery performance are key factors that nurture the value of relationships between manufacturers and distributors. These findings confirm the role of relationship value in transition economies.

Expert Opinion on Pharmacotherapy, 2005

The discovery of two distinct isoenzymes of COX has led to the development and clinical introduct... more The discovery of two distinct isoenzymes of COX has led to the development and clinical introduction of COX-2 inhibitors with increased selectivity onto the market. Meloxicam is a non-steroidal anti-inflammatory drug (NSAID) of the oxicam class, and is a preferential inhibitor of COX-2, demonstrating effectiveness with anti-inflammatory, analgesic and antipyretic activity. Meloxicam is therapeutically utilised in the management of osteoarthritis and rheumatoid arthritis. Trials have examined the risk of gastrointestinal ulceration of meloxicam when compared with traditional non-specific COX-inhibiting NSAIDs with mixed results; meloxicam seems to have a greater gastrointestinal risk than the highly specific COX-2 NSAIDs. Meloxicam has a plasma half-life of approximately 20 h and is convenient for once daily administration. Neither moderate renal nor hepatic insufficiency significantly alters the pharmacokinetics of meloxicam in short-term studies. Furthermore, dose adjustment is not required in the elderly. Recent drug-drug interaction studies have demonstrated that meloxicam interacts with some medications, including cholestyramine, lithium and some inhibitors of cytochrome P450 -2C9 and -3A4. Consequently, increased clinical vigilance should be maintained when coprescribing some medications with meloxicam. Concentration-dependent therapeutic and toxicological effects have yet to be extensively elucidated for meloxicam. Long-term safety in various organ systems, especially in the heart and vascular system and with concomitant drug administration, remains to be proven. The pharmacokinetics of meloxicam enables once daily application, which increases compliance compared with some shorter acting NSAIDs; however, long-term clinical data clearly demonstrating safety and efficacy advantages are lacking.

Journal of electron microscopy, 2003

Membrane vesicles (MVs) were isolated from three isogenic lipopolysaccharide (LPS) mutants derive... more Membrane vesicles (MVs) were isolated from three isogenic lipopolysaccharide (LPS) mutants derived from the Gram-negative bacterium Pseudomonas aeruginosa PAO1 and compared with the parent strain. Parent cells possessed serotype 05 (A+B+) LPS whereas the three mutants contained A+B-, A-B+ and A-B-. The MVs from the mutants contained their expected phenotypic LPS and varied in size, especially A-B- MVs. Mass and total protein differences were also noted. When the parent and mutant cells were treated with the outer membrane-perturbing antibiotic gentamicin, all cells produced 3-5 times more MVs and these had great variation in size, mass and total protein. It is concluded that the type of cellular LPS affects both the natural and gentamicin-induced development of MVs.

Cell calcium, Jan 28, 2015

Live cell imaging has revealed that calcium ions (Ca(2+)) pass in and out of many cellular organe... more Live cell imaging has revealed that calcium ions (Ca(2+)) pass in and out of many cellular organelles. However, technical hurdles have limited measurements of Ca(2+) in acidic organelles, such as endosomes. Although evidence hints that endosomes play a role in Ca(2+) signaling, direct measurements within endosomal lumina represent one of the final frontiers in organelle imaging. To measure Ca(2+) in a TiVAMP-positive endosome sub-population, the pH-resistant ratiometric Ca(2+) biosensor GEM-GECO1 and the ratiometric pH biosensor mKeima were used. A positive correlation between acidic endosomal pH and higher Ca(2+) was observed within these Rab5a- and Rab7-positive compartments. Ca(2+) concentration in most endosomes was estimated to be below 2μM, lower than Ca(2+) levels in several other intracellular stores, indicating that endosomes may take up Ca(2+) during physiological stimulation. Indeed, endosomes accumulated Ca(2+) during glucose-stimulation, a condition where endosomal pH did not change. Our biosensors permitted the first measurements revealing a role for endosomes in cellular Ca(2+) homeostasis during physiological stimulation.

Asian-Australasian journal of animal sciences, 2015

Castration induces the accumulation of body fat and deposition of intramuscular fat in Korean cat... more Castration induces the accumulation of body fat and deposition of intramuscular fat in Korean cattle, resulting in improved beef quality. However, little is known about the metabolic adaptations in the liver following castration. To understand changes in lipid metabolism following castration, hepatic expression levels of lipid metabolism genes were compared between Korean bulls and steers. Steers had higher (p<0.001) hepatic lipids contents and higher (p<0.01) mRNA levels of lipogenic acetyl-CoA carboxylase. This differential gene expression may, in part, contribute to increased hepatic lipid content following the castration of bulls. However, we found no differences in the hepatic expression levels of genes related to triglyceride synthesis (mitochondrial glycerol-3-phosphate acyltransferase, diacylglycerol O-acyltransferase 1 and 2) and fatty acid (FA) oxidation (carnitine palmitoyltransferase 1A, C-4 to C-12 straight chain acyl-CoA dehydrogenase, very long chain acyl-CoA dehydrogenase) between bulls and steers. No differences in gene expression for very-low-density lipoprotein (VLDL) secretion, including apolipoprotein B mRNA and microsomal triglyceride transfer protein (MTTP) protein, were observed in the liver although MTTP mRNA levels were higher in steers compared to bulls. In conclusion, FA synthesis may contribute to increased hepatic lipid deposition in steers following castration. However, hepatic lipid metabolism, including triglyceride synthesis, FA oxidation, and VLDL secretion, was not significantly altered by castration. Our results suggest that hepatic lipid metabolism does not significantly contribute to increased body fat deposition in steers following castration.

Archives of surgery (Chicago, Ill. : 1960), 2010

Clinical journal of the American Society of Nephrology : CJASN, 2011

Background and objectives Insulin has several physiologic actions that include stimulation of cel... more Background and objectives Insulin has several physiologic actions that include stimulation of cellular glucose and potassium uptake. The ability of insulin to induce glucose uptake by cells is impaired in type 2 diabetes mellitus, but whether potassium uptake is similarly impaired is not known. This study examines whether the cellular uptake of these molecules is regulated in concert or independently.

Neurological Research, 2011

Stereotactic radiosurgery is a modern addition to the armamentarium of treatment options for intr... more Stereotactic radiosurgery is a modern addition to the armamentarium of treatment options for intracranial and extracranial lesions. It is increasingly being used as an adjuvant to surgery, conventional radiation therapy, and chemotherapy as well as being used as primary treatment. Since the introduction of the Gamma Knife (Elekta, Stockholm, Sweden) system, many more stereotactic radiosurgery machines have become available. The objective of this review is to compare and contrast the various currently available stereotactic radiosurgery platforms.

Infection and Drug Resistance, 2011

The effectiveness of pandemic vaccine campaigns such as the H1N1 vaccine rollout is dependent on ... more The effectiveness of pandemic vaccine campaigns such as the H1N1 vaccine rollout is dependent on both the vaccines' effectiveness and the general public's willingness to be vaccinated. It is therefore critical to understand the factors that influence the decision of members of the public whether to get vaccinated with new, emergently released vaccines. A systematic review of English language quantitative surveys was conducted to identify consistent predictors of the decision to accept or decline any (pre)pandemic vaccine, including the H1N1 influenza A vaccine. A total of ten studies were included in this review and all pertained to the 2009 H1N1 influenza A pandemic.…

Chlamydia prevalence varies regionally but is highest in the South, which could be the result of ... more Chlamydia prevalence varies regionally but is highest in the South, which could be the result of regional differences in testing behavior. We describe the national and regional prevalence of self-reported chlamydial infection (Ct) testing and examine how financial resources might be associated with Ct testing. We conducted a cross-sectional analysis of data from 12,334 sexually experienced young adults who participated in wave III of the National Longitudinal Study of Adolescent Health (2001-2002). We estimated the prevalence of Ct testing by region and gender, and calculated prevalence odds ratios for the relationship between income or insurance status and Ct testing. Among women, Ct testing in the past year was low (27.3%; 95% CI, 25.5-29.2) and lowest in the South (24.8%). Compared with publicly insured females, privately insured (OR, 0.72; 95% CI, 0.57-0.92) and uninsured females (OR, 0.63; 95% CI, 0.48-0.88) were less likely to report testing. Young women with low income were more likely to report testing than those with a higher income (OR, 1.36; 95% CI, 1.12-1.66). Men reported similar testing patterns. The South has the highest chlamydia prevalence and the lowest levels of Ct testing in the United States. Reducing infection prevalence and regional disparities in the burden of this infection requires region-focused funding and innovative strategies to increase testing and treatment programs.

Journal of safety …, 2003

Outcome measures for safety training effectiveness research often do not include measures such as... more Outcome measures for safety training effectiveness research often do not include measures such as occupational injury experience. Effectiveness mediators also receive sparse attention. A new safety training curriculum was delivered to workers in a stratified random sample of food service facilities across three companies. A similar group of facilities received usual training. We collected post-test measures of demographic variables, safety knowledge, perceptions of transfer of training climate, and workers' compensation claim data for one year after the initial training activities. Knowledge test scores were apparently higher in the new-training units than in the usual-training units. Some demographic variables were inconsistently associated with these differences. Evidence for reduction of the injury rate associated with the new training was observed from two companies but only approached significance for one company. A second company revealed a similar but non-significant trend. Knowledge scores were not significantly associated with lower injury rates. We found evidence that safety training increases knowledge and reduces injuries. We found almost no evidence of effects of training effectiveness mediators, including no relationship between safety knowledge and injury experience. Methodological issues related to conducting a large study may have influenced these results. Although safety training leads to greater knowledge and, in some cases, reduced occupational injuries, the influence of mediating variables remains to be fully explained.

Public Health Reports, 2003

As the HIV epidemic has changed nationally, the parallel change in the Southern states has been a... more As the HIV epidemic has changed nationally, the parallel change in the Southern states has been a disproportionate increase in HIV infection among people of color and among women. Due to the limited and disjointed health care and social service resources in rural Southern regions, already marginalized groups have difficulty in accessing appropriate care and services to address their HIV infection seamlessly and with continuity. To ameliorate the limitations in the health care infrastructure, the North Carolina Services Integration Project collaborated with North Carolina medical and social service providers and state agencies to create a sustainable and replicable model of integrated care for HIV-positive, geographically dispersed residents.

Vaccine, 2006

We investigated effects of low titer (Lo) circulating MatAb on protection and immunogenicity of a... more We investigated effects of low titer (Lo) circulating MatAb on protection and immunogenicity of attenuated (Att) human rotavirus (HRV) priming and 2/6-virus-like particle (VLP)-immunostimulating complex (ISCOM) boosting (AttHRV/VLP) or VLP-ISCOM alone vaccines. LoMatAb had both enhancing and suppressing effects on B cell responses, depending on tissue, antibody isotype and vaccine. Differential effects of LoMatAb on IgA responses in different tissues suggest that LoMatAb did not suppress induction of IgA effector and memory B cells but impaired homing of these cells to secondary lymphoid or effector tissues, reducing IgA antibody secreting cells and antibodies at these sites. The AttHRV/VLP vaccine partially overcame LoMatAb suppression, conferred moderate protection against virulent HRV (as measured by reduced viral shedding and diarrhea) and represents a new candidate for rotavirus vaccines for both humans and animals.

Clinical and Vaccine …, 2004

A sequential mucosal prime-boost vaccine regimen of oral attenuated (Att) human rotavirus (HRV) p... more A sequential mucosal prime-boost vaccine regimen of oral attenuated (Att) human rotavirus (HRV) priming followed by intranasal (i.n.) boosting with rotavirus protein VP2 and VP6 rotavirus-like particles (2/6-VLPs) has previously been shown to be effective for induction of intestinal antibody-secreting cell (ASC) responses and protection in gnotobiotic pigs. Because serum or fecal antibody titers, but not intestinal ASC responses, can be used as potential markers of protective immunity in clinical vaccine trials, we determined the serum and intestinal antibody responses to this prime-boost rotavirus vaccine regimen and the correlations with protection. Gnotobiotic pigs were vaccinated with one of the two sequential vaccines: AttHRV orally preceding 2/6-VLP (VLP2x) vaccination (AttHRV/VLP2x) or following VLP2x vaccination (VLP2x/AttHRV) given i.n. with a mutant Escherichia coli heat-labile toxin (mLT) as adjuvant. These vaccines were also compared with three i.n. doses of VLP+mLT (VLP3x) and one and three oral doses of AttHRV (AttHRV1x and AttHRV3x, respectively). Before challenge all pigs in the AttHRV/VLP2x group seroconverted to positivity for serum immunoglobulin A (IgA) antibodies. The pigs in this group also had significantly higher (P < 0.05) intestinal IgA antibody titers pre- and postchallenge and IgG antibody titers postchallenge compared to those in the other groups. Statistical analyses of the correlations between serum IgM, IgA, IgG, and virus-neutralizing antibody titers and protection demonstrated that each of these was an indicator of protective immunity induced by the AttHRV3x and the AttHRV/VLP2x regimens. However, only IgA and not IgM or IgG antibody titers in serum were highly correlated (R2 = 0.89; P < 0.001) with the corresponding isotype antibody (IgA) titers in the intestines among all…

Veterinary immunology …, 2007

Maternal cytokines may play instructive roles in development of the neonatal immune system. Howev... more Maternal cytokines may play instructive roles in development of the neonatal immune system. However, cytokines in colostrum and milk and their transfer from mothers to neonates have not been well documented, except for TGF-b. Swine provide a unique model to study lactogenic cytokines because the sow's impermeable placenta prohibits transplacental passage. We investigated IL-6 and TNF-a (pro-inflammatory), IFN-g and IL-12 (Th1), IL-10 and IL-4 (Th2) and TGF-b1 (Th3) concentrations in sow serum and colostrum/milk and serum of their suckling and weaned piglets and in age-matched colostrum-deprived gnotobiotic piglets. All cytokines were detected in colostrum/milk and correlated with concentrations in sow serum except for mammary-derived TNF-a and TGF-b1. Detection of IL-12 and TGF-b1 in pre-suckling and colostrum-deprived gnotobiotic piglet serum suggests constitutive production: other cytokines were undetectable confirming absence of transplacental transfer. Peak median cytokine concentrations in suckling piglet serum occurred at post-partum days 1-2 (IL-4 > IL-6 > IFN-g > IL-10). The effects in vitro of physiologically relevant concentrations of the two predominant lactogenic cytokines (TGF-b1 and IL-4) on porcine naive B cell responses to lipopolysaccharide (LPS) and rotavirus (RV) were investigated. High (10 ng/ml) TGF-b1 suppressed immunoglobulin secreting cell responses to LPS and rotavirus; low concentrations (0.1 ng/ml) promoted isotype switching to IgA antibody. Interleukin-4 induced inverse dose-dependent (0.1 ng > 10 ng/ml) isotype switching to IgA and enhanced IgM secreting cell responses to LPS and rotavirus. In summary, we documented the transfer and persistence of maternal cytokines from colostrum/milk to neonates and their potential role in Th-2 biased IgA responses and reduced immunologic responsiveness of neonates. #

Clinical and vaccine …, 2006

Gnotobiotic pigs were injected intraperitoneally at birth with pooled serum from sows hyperimmuni... more Gnotobiotic pigs were injected intraperitoneally at birth with pooled serum from sows hyperimmunized with human rotavirus (HRV); control pigs received no sow serum. Pigs with or without MatAbs received either sequential attenuated HRV (AttHRV) oral priming and intranasal boosting with VP2/VP6 virus-like particle (VLP)-immunostimulating complex (ISCOM) (AttHRV/VLP) or intranasal VLP-ISCOM prime/boost (VLP) vaccines at 3 to 5 days of age. Subsets of pigs were challenged at 28 or 42 days postinoculation with virulent Wa HRV to assess protection.

JAIDS Journal of …, 2005

Background: Approximately 16 million people are enrolled in institutions of higher learning in th... more Background: Approximately 16 million people are enrolled in institutions of higher learning in the United States. However, college students have not been perceived as at high risk for HIV infection. In early 2003, acute HIV infection was diagnosed in 2 men attending college in North Carolina. We describe an epidemiologic investigation of newly diagnosed HIV infection in men attending college in North Carolina. Methods: We reviewed state surveillance records examining new HIV diagnoses in men 18-30 years old between January 1, 2000 and December 31, 2003, living in 69 North Carolina counties. Risk behavior and demographic information for HIV-infected men enrolled in college were compared with HIV-infected male nonenrollees.

Background: The emerging epidemic of overweight/obesity in adolescents in Ho Chi Minh City, Vietn... more Background: The emerging epidemic of overweight/obesity in adolescents in Ho Chi Minh City, Vietnam underlines the importance of studying the metabolic syndrome in Vietnamese adolescents who are becoming progressively more inactive. No study in Vietnam has examined the association of metabolic syndrome with moderate to vigorous physical activity (PA) levels among adolescents. We aimed to examine this association in a sample of urban adolescents from Ho Chi Minh City. Methods: A cross-sectional assessment was conducted in 2007 on a representative sample of 693 high-school students from urban districts in Ho Chi Minh City. Metabolic syndrome was defined according to the International Diabetes Federation criteria and physical activity was measured with Actigraph accelerometers. The association between physical activity and metabolic syndrome was assessed by using multiple logistic regression models.

This study explores key antecedents and an outcome of relationship value between manufacturers an... more This study explores key antecedents and an outcome of relationship value between manufacturers and distributors in the tile industry in a transition market -Vietnam. Using a sample of 317 distributors in the South of Vietnam, we found that relationship value is a key factor that drives the performance of distributors. In addition, product quality, information services, and delivery performance are key factors that nurture the value of relationships between manufacturers and distributors. These findings confirm the role of relationship value in transition economies.

Expert Opinion on Pharmacotherapy, 2005

The discovery of two distinct isoenzymes of COX has led to the development and clinical introduct... more The discovery of two distinct isoenzymes of COX has led to the development and clinical introduction of COX-2 inhibitors with increased selectivity onto the market. Meloxicam is a non-steroidal anti-inflammatory drug (NSAID) of the oxicam class, and is a preferential inhibitor of COX-2, demonstrating effectiveness with anti-inflammatory, analgesic and antipyretic activity. Meloxicam is therapeutically utilised in the management of osteoarthritis and rheumatoid arthritis. Trials have examined the risk of gastrointestinal ulceration of meloxicam when compared with traditional non-specific COX-inhibiting NSAIDs with mixed results; meloxicam seems to have a greater gastrointestinal risk than the highly specific COX-2 NSAIDs. Meloxicam has a plasma half-life of approximately 20 h and is convenient for once daily administration. Neither moderate renal nor hepatic insufficiency significantly alters the pharmacokinetics of meloxicam in short-term studies. Furthermore, dose adjustment is not required in the elderly. Recent drug-drug interaction studies have demonstrated that meloxicam interacts with some medications, including cholestyramine, lithium and some inhibitors of cytochrome P450 -2C9 and -3A4. Consequently, increased clinical vigilance should be maintained when coprescribing some medications with meloxicam. Concentration-dependent therapeutic and toxicological effects have yet to be extensively elucidated for meloxicam. Long-term safety in various organ systems, especially in the heart and vascular system and with concomitant drug administration, remains to be proven. The pharmacokinetics of meloxicam enables once daily application, which increases compliance compared with some shorter acting NSAIDs; however, long-term clinical data clearly demonstrating safety and efficacy advantages are lacking.

Journal of electron microscopy, 2003

Membrane vesicles (MVs) were isolated from three isogenic lipopolysaccharide (LPS) mutants derive... more Membrane vesicles (MVs) were isolated from three isogenic lipopolysaccharide (LPS) mutants derived from the Gram-negative bacterium Pseudomonas aeruginosa PAO1 and compared with the parent strain. Parent cells possessed serotype 05 (A+B+) LPS whereas the three mutants contained A+B-, A-B+ and A-B-. The MVs from the mutants contained their expected phenotypic LPS and varied in size, especially A-B- MVs. Mass and total protein differences were also noted. When the parent and mutant cells were treated with the outer membrane-perturbing antibiotic gentamicin, all cells produced 3-5 times more MVs and these had great variation in size, mass and total protein. It is concluded that the type of cellular LPS affects both the natural and gentamicin-induced development of MVs.