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Dive into the research topics where Margarita Silio is active.

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Featured researches published by Margarita Silio.


The Journal of Infectious Diseases | 2004

Virologic and Immunologic Outcomes after 24 Weeks in HIV Type 1-Infected Adolescents Receiving Highly Active Antiretroviral Therapy

Patricia M. Flynn; Bret J. Rudy; Steven D. Douglas; Janet L. Lathey; Stephen A. Spector; Jaime Martinez; Margarita Silio; Marvin Belzer; Lawrence S. Friedman; Lawrence J. D'Angelo; James McNamara; Janice Hodge; Michael D. Hughes; Jane C. Lindsey; M. E. Pau; L. Noroski; William Borkowsky; T. Hastings; S. Bakshi; Murli Purswani; Ana Puga; D. Cruz; M. J. O'Hara; Ann J. Melvin; K. M. Mohan; Cathryn L. Samples; M. Cavallo; Diane Tucker; Mary Tanney; Carol Vincent

BACKGROUND Adolescents represent the fastest growing demographic group of new human immunodeficiency virus (HIV) infections in the United States. At present, there is little information available about their response to therapy. METHODS We studied 120 adolescents infected via high-risk behaviors who began receiving highly active antiretroviral therapy (HAART), to determine their virologic and immunologic response to therapy. RESULTS Subjects were enrolled at 28 sites of the Pediatric Acquired Immunodeficiency Syndrome Clinical Trials Group. After 16-24 weeks of HAART, 59% of subjects had reproducible undetectable virus loads, according to repeat measurements (virologic success). As enumerated by flow-cytometric analysis, increases in levels of CD4 helper cells (both naive and memory) and decreases in levels of CD8 suppressor cells were observed. Partial restoration of some immunologic parameters for patients who did not achieve virologic success was also observed, but to a more limited extent than for adolescents with virologic success. Adherence to HAART was the only predictor of achieving undetectable virus loads. CONCLUSIONS Adolescents have the capacity to improve their immunologic status with HAART. Lower than expected success in virologic control is related to lack of adherence, and efforts to improve treatment outcome must stress measures to assure adherence to medication.


The American Journal of Clinical Nutrition | 2011

Body fat distribution in perinatally HIV-infected and HIV-exposed but uninfected children in the era of highly active antiretroviral therapy: outcomes from the Pediatric HIV/AIDS Cohort Study

Denise L. Jacobson; Kunjal Patel; George K. Siberry; Russell B. Van Dyke; Linda A. DiMeglio; Mitchell E. Geffner; Janet S. Chen; Elizabeth J. McFarland; William Borkowsky; Margarita Silio; Roger A. Fielding; Suzanne Siminski; Tracie L. Miller

BACKGROUND Associations between abnormal body fat distribution and clinical variables are poorly understood in pediatric HIV disease. OBJECTIVE Our objective was to compare total body fat and its distribution in perinatally HIV-infected and HIV-exposed but uninfected (HEU) children and to evaluate associations with clinical variables. DESIGN In a cross-sectional analysis, children aged 7-16 y in the Pediatric HIV/AIDS Cohort Study underwent regionalized measurements of body fat via anthropometric methods and dual-energy X-ray absorptiometry. Multiple linear regression was used to evaluate body fat by HIV, with adjustment for age, Tanner stage, race, sex, and correlates of body fat in HIV-infected children. Percentage total body fat was compared with NHANES data. RESULTS Males accounted for 47% of the 369 HIV-infected and 51% of the 176 HEU children. Compared with HEU children, HIV-infected children were older, were more frequently non-Hispanic black, more frequently had Tanner stage ≥3, and had lower mean height (-0.32 compared with 0.29), weight (0.13 compared with 0.70), and BMI (0.33 compared with 0.63) z scores. On average, HIV-infected children had a 5% lower percentage total body fat (TotF), a 2.8% lower percentage extremity fat (EF), a 1.4% higher percentage trunk fat (TF), and a 10% higher trunk-to-extremity fat ratio (TEFR) than did the HEU children and a lower TotF compared with NHANES data. Stavudine use was associated with lower EF and higher TF and TEFR. Non-nucleotide reverse transcriptase inhibitor use was associated with higher TotF and EF and lower TEFR. CONCLUSION Although BMI and total body fat were significantly lower in the HIV-infected children than in the HEU children, body fat distribution in the HIV-infected children followed a pattern associated with cardiovascular disease risk and possibly related to specific antiretroviral drugs.


Hormone Research in Paediatrics | 2011

Factors Associated with Insulin Resistance among Children and Adolescents Perinatally Infected with HIV-1 in the Pediatric HIV/AIDS Cohort Study

Mitchell E. Geffner; Kunjal Patel; Tracie L. Miller; Rohan Hazra; Margarita Silio; Russell B. Van Dyke; William Borkowsky; Carol Worrell; Linda A. DiMeglio; Denise L. Jacobson

Background/Aims: Because of prior inconsistent findings, we studied a large cohort of HIV-infected children to determine: (1) prevalence of insulin resistance (IR); (2) anthropometric and clinical correlates of IR, and (3) concomitant abnormalities of glucose tolerance. Methods: The study population consisted of 451 children from the Pediatric HIV/AIDS Cohort Study. The outcome of interest was HOMA-IR. Covariates included demographic, metabolic, growth, body composition, HIV laboratory tests, and treatment characteristics. Children meeting triggers for IR underwent oral glucose tolerance tests and hemoglobin A1c (HbA1c) measurements. Results: Among 402 children with glucose and insulin measurements, 15.2% had IR of whom 79% were pubertal. IR was associated with higher alanine aminotransferase, body mass index, and nadir CD4%, Tanner stage 5, and ever having received amprenavir. Of those with IR, three had impaired fasting glucose (IFG), three impaired glucose tolerance (IGT), one IFG and IGT, none diabetic glucose tolerance, and three HbA1c between 6.1 and 6.5%. Conclusion: In our cohort of HIV-infected adolescents, we observed a 15.2% prevalence of IR more closely linked to obesity than any other variable. This finding mirrors the high prevalence of obesity-mediated IR in American youth. However, associations with CD4 count and use of protease inhibitors may indicate some effect of HIV and/or its treatment.


AIDS | 2013

Pubertal onset in children with perinatal HIV infection in the era of combination antiretroviral treatment.

Paige L. Williams; Mark J. Abzug; Denise L. Jacobson; Jiajia Wang; Russell B. Van Dyke; Rohan Hazra; Kunjal Patel; Linda A. DiMeglio; Elizabeth J. McFarland; Margarita Silio; William Borkowsky; George R. Seage; James M. Oleske; Mitchell E. Geffner

Objective:To evaluate associations of perinatal HIV infection, HIV disease severity, and combination antiretroviral treatment with age at pubertal onset. Design:Analysis of data from two US longitudinal cohort studies (IMPAACT 219C and PHACS AMP), conducted during 2000–2012, including perinatally HIV-infected (PHIV) and HIV-exposed but uninfected (HEU) youth. Tanner stage assessments of pubertal status (breast and pubic hair in girls; genitalia and pubic hair in boys) were conducted annually. Methods:We compared the timing of pubertal onset (Tanner stage ≥2) between PHIV and HEU youth using interval-censored models. For PHIV youth, we evaluated associations of HIV disease severity and combination antiretroviral treatment with age at pubertal onset, adjusting for race/ethnicity and birth cohort. Results:The mean age at pubertal onset was significantly later for the 2086 PHIV youth compared to the 453 HEU children (10.3 vs. 9.6, 10.5 vs. 10.0, 11.3 vs. 10.4, and 11.5 vs. 10.7 years according to female breast, female pubic hair, male genitalia, and male pubic hair staging, respectively, all P < 0.001). PHIV youth with HIV-1 RNA viral load above 10 000 copies/ml (vs. ⩽10 000 copies/ml) or CD4% below 15% (vs. ≥15%) had significantly later pubertal onset (by 4–13 months). Each additional year of combination antiretroviral treatment was associated with a 0.6–1.2-month earlier mean age at pubertal onset, but this trend did not persist after adjustment for birth cohort. Conclusion:Pubertal onset occurs significantly later in PHIV than in HEU youth, especially among those with more severe HIV disease. However, in the current era, combination antiretroviral treatment may result in more normal timing of pubertal onset.


Epidemiology and Infection | 2009

Prevalence of community-associated methicillin-resistant Staphylococcus aureus colonization outside the healthcare environment

S. Malik; P. Vranken; Margarita Silio; Raoult Ratard; R. B. Van Dyke

Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infections are increasingly recognized in persons without established risk factors. Population-based prevalence studies of CA-MRSA colonization in persons without risk factors are relatively limited. Subjects aged 2-65 years were enrolled from a student recreation centre, public office building, and out-patient clinics. Persons or close contacts with a history of hospitalization, nursing-home residence, surgery, emergency-department visit, or healthcare employment during the previous year and persons with chronic debilitating illness, indwelling catheter, or surgical device were excluded. Swabs of anterior nares were obtained. Demographic and clinical information was collected. During January-June 2005, three (1.2%) of 259 subjects were colonized with MRSA. All three subjects were adults enrolled at the recreation centre. Healthy persons living in households without recent exposure to healthcare environments were at low risk for MRSA colonization. Studies from other geographic locations are needed to elucidate differences in prevalence of CA-MRSA.


Clinical Infectious Diseases | 2016

Antiretroviral Drug Resistance Among Children and Youth in the United States With Perinatal HIV

Russell B. Van Dyke; Kunjal Patel; Ron M. Kagan; Brad Karalius; Shirley Traite; William A. Meyer; Katherine Tassiopoulos; George R. Seage; Lorna M. Seybolt; Sandra K. Burchett; Rohan Hazra; Robert H. Lurie; Ram Yogev; Margaret Ann Sanders; Kathleen Malee; Scott J. Hunter; William T. Shearer; Mary E. Paul; Norma Cooper; Lynnette L. Harris; Murli Purswani; Mahboobullah Baig; Anna Cintron; Ana Puga; Sandra Navarro; Patricia A. Garvie; James Blood; Nancy Karthas; Betsy Kammerer; Andrew Wiznia

Among 234 US youths with perinatal human immunodeficiency virus, 75% had antiretroviral resistance, substantially higher than that of the reference laboratory overall (36%-44%). Resistance to newer antiretrovirals and to all antiretrovirals in a class was uncommon. The only factor independently associated with future resistance was a higher peak viral load.


Pediatric Infectious Disease Journal | 2017

Growth at 2 years of age in HIV-exposed uninfected children in the United States by trimester of maternal antiretroviral initiation

Denise L. Jacobson; Kunjal Patel; Paige L. Williams; Mitchell E. Geffner; George K. Siberry; Linda A. DiMeglio; Marilyn J. Crain; Ayesha Mirza; Janet S. Chen; Elizabeth J. McFarland; Deborah Kacanek; Margarita Silio; Kenneth Rich; William Borkowsky; Russell B. Van Dyke; Tracie L. Miller

Background: Abnormal childhood growth may affect future health. Maternal tenofovir (TFV) use was associated with lower body length and head circumference at 1 year of age in HIV-exposed uninfected (HEU) US children. Methods: We studied 509 HEU children in the US-based Surveillance Monitoring of Antiretroviral Therapy Toxicities cohort whose HIV-infected mothers were not using antiretrovirals at the last menstrual period and began combination antiretroviral therapy (cART) in pregnancy (cART initiators). We examined adjusted associations between antiretrovirals and Centers for Disease Control 2000 growth Z scores at 2 years of age within trimester of cART initiation: weight (weight Z score), length (length Z score), weight-for-length [weight-for-length Z score (WFLZ)], triceps skinfold Z score (TSFZ) and head circumference (head circumference Z score). Results: Mothers mean age was 28.6 years; 57% were black non-Hispanic and 19% delivered at <37 weeks gestation. At 2 years, mean weight Z score, length Z score, WFLZ and head circumference Z score were above average (P < 0.05), whereas TSFZ (P = 0.57) did not differ from average. WFLZ was >1.64 standard deviation (SD) (>95th percentile) in 13%. Among children of first-trimester cART initiators, TFV+emtricitabine–exposed children had slightly higher mean WFLZ (0.45 SD; 95% confidence interval: −0.10 to 1.00) and lower TSFZ (−0.55 SD; 95% confidence interval: −1.07 to −0.02) compared with zidovudine+lamivudine–exposed children. TSFZ was lower in those exposed to boosted protease inhibitors. In contrast, growth in children of second trimester cART initiators did not differ by antiretroviral exposures. Conclusion: Growth was above average in HEU; 13% were obese. Maternal TFV use was not associated with lower length or head circumference at 2 years of age, as hypothesized, but may be related to greater weight among those exposed to cART early in pregnancy.


Clinical Infectious Diseases | 2017

Human Immunodeficiency Virus Type 1 DNA Decay Dynamics With Early, Long-term Virologic Control of Perinatal Infection

Priyanka Uprety; Kunjal Patel; Brad Karalius; Carrie Ziemniak; Ya Hui Chen; Sean Brummel; Suzanne Siminski; Russell B. Van Dyke; George R. Seage; Deborah Persaud; Ram Yogev; Margaret Ann Sanders; Kathleen Malee; Scott J. Hunter; William T. Shearer; Mary E. Paul; Norma Cooper; Lynnette L. Harris; Murli Purswani; Mahboobullah Baig; Anna Cintron; Ana Puga; Sandra Navarro; Patricia A. Garvie; James Blood; Sandra K. Burchett; Nancy Karthas; Betsy Kammerer; Andrew Wiznia; Marlene Burey

Background. Early antiretroviral therapy (ART) limits proviral reservoirs, a goal for human immunodeficiency virus type 1 (HIV-1) remission strategies. Whether this is an immediate or long-term effect of virologic suppression (VS) in perinatal infection is unknown. Methods. We quantified HIV-1 DNA longitudinally for up to 14 years in peripheral blood mononuclear cells (PBMCs) among 61 perinatally HIV-1-infected youths in the Pediatric HIV/AIDS Cohort Study who achieved VS at different ages. Participants in group 1 (n = 13) were <1 year of age and in group 2 (n = 48) from 1 through 5 years of age at VS. Piecewise linear mixed-effects regression models assessed the effect of age at VS on HIV-1 DNA trajectories during VS. Results. In the first 2 years following VS, HIV-1 DNA levels decreased by -0.25 (95% confidence interval [CI], -.36 to -.13) log10 copies/million PBMCs per year and was faster with early VS by age 1 year compared with after age 1 (-0.50 and -0.15 log10 copies/million PBMCs per year, respectively). Between years 2 and 14 from VS, HIV-1 DNA decayed by -0.05 (95% CI, -.06 to -.03) log10 copies/million PBMCs per year and was no longer significantly different between groups. The estimated mean half-life of HIV-1 DNA from VS was 15.9 years and was shorter for group 1 compared to group 2 at 5.9 years and 18.8 years, respectively (P = .09). Adjusting for CD4 cell counts had no effect on decay estimates. Conclusions. Early effective, long-term ART initiated from infancy leads to decay of HIV-1-infected cells to exceedingly low concentrations desired for HIV-1 remission strategies.


Journal of Acquired Immune Deficiency Syndromes | 2017

Associations of low Vitamin D and elevated parathyroid hormone concentrations with bone mineral density in perinatally HIV-infected children

Denise L. Jacobson; Charles B. Stephensen; Tracie L. Miller; Kunjal Patel; Janet S. Chen; Russell B. Van Dyke; Ayesha Mirza; Gertrud U. Schuster; Rohan Hazra; Angela Ellis; Sean Brummel; Mitchell E. Geffner; Margarita Silio; Stephen A. Spector; Linda A. DiMeglio

Background: Perinatally HIV-infected (PHIV) children have, on average, lower bone mineral density (BMD) than perinatally HIV-exposed uninfected (PHEU) and healthy children. Low 25-hydroxy vitamin D [25(OH)D] and elevated parathyroid hormone (PTH) concentrations may lead to suboptimal bone accrual. Methods: PHIV and PHEU children in the Pediatric HIV/AIDS Cohort Study had total body (TB) and lumbar spine (LS) BMD and bone mineral content (BMC) measured by dual-energy x-ray absorptiometry; BMD z-scores (BMDz) were calculated for age and sex. Low 25(OH)D was defined as ⩽20 ng/mL and high PTH as >65 pg/mL. We fit linear regression models to estimate the average adjusted differences in BMD/BMC by 25(OH)D and PTH status and log binomial models to determine adjusted prevalence ratios of low 25(OH)D and high PTH in PHIV relative to PHEU children. Results: PHIV children (n = 412) were older (13.0 vs. 10.8 years) and more often black (76% vs. 64%) than PHEU (n = 207). Among PHIV, children with low 25(OH)D had lower TB-BMDz [SD, −0.38; 95% confidence interval (CI), −0.60 to −0.16] and TB-BMC (SD, −59.1 g; 95% CI, −108.3 to −9.8); high PTH accompanied by low 25(OH)D was associated with lower TB-BMDz. Among PHEU, children with low 25(OH)D had lower TB-BMDz (SD, −0.34; 95% CI, −0.64 to −0.03). Prevalence of low 25(OH)D was similar by HIV status (adjusted prevalence ratio, 1.00; 95% CI, 0.81 to 1.24). High PTH was 3.17 (95% CI, 1.25 to 8.06) times more likely in PHIV children. Conclusions: PHIV and PHEU children with low 25(OH)D may have lower BMD. Vitamin D supplementation trials during critical periods of bone accrual are needed.


Hiv Medicine | 2018

Improvement in lipids after switch to boosted atazanavir or darunavir in children/adolescents with perinatally acquired HIV on older protease inhibitors: Results from the Pediatric HIV/AIDS Cohort Study

Jennifer Jao; Wendy Yu; Kunjal Patel; Tracie L. Miller; Brad Karalius; Mitchell E. Geffner; Linda A. DiMeglio; Ayesha Mirza; Janet S. Chen; Margarita Silio; Elizabeth J. McFarland; R. B. Van Dyke; Denise L. Jacobson

Dyslipidaemia is common in perinatally HIV‐infected (PHIV) youth receiving protease inhibitors (PIs). Few studies have evaluated longitudinal lipid changes in PHIV youth after switch to newer PIs.

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Mitchell E. Geffner

University of Southern California

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Rohan Hazra

National Institutes of Health

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