Jacob Abadi

Bio: Jacob Abadi is an academic researcher from New York City Health and Hospitals Corporation. The author has contributed to research in topics: Prenatal care & Cryptococcus neoformans. The author has an hindex of 2, co-authored 2 publications receiving 437 citations.

Serologic evidence for Cryptococcus neoformans infection in early childhood.

Abstract: Objective. Cryptococcus neoformans is an important cause of central nervous system infection in adults with acquired immunodeficiency syndrome (AIDS) but an unusual cause of disease in children with AIDS. The basis for this age-related difference in incidence is not known but may be caused by differences in exposure or immune response. The objective of this study was to determine whether the low prevalence of cryptococcal disease among children is related to a lack of exposure to C neoformans . Methods. Sera were obtained from 185 immunocompetent individuals ranging in age from 1 week to 21 years who were being evaluated in an urban emergency department. Sera were analyzed for antibodies to C neoformans and Candida albicans proteins by immunoblotting. Immunoblot patterns were compared with those obtained from sera of patients with cryptococcosis ( n = 10) and workers in a laboratory devoted to the study of C neoformans . The specificity of our results was confirmed by several approaches, including antibody absorption and blocking studies. Sera were also analyzed for the presence of cryptococcal polysaccharide by both enzyme-linked immunosorbent assay and latex agglutination assays. Results. Sera from children 1.1 to 2 years old demonstrated minimal reactivity to C neoformans proteins. In contrast, the majority of sera from children >2 years old recognized many (≥6) C neoformans proteins. For children between 2.1 and 5 years old, 56% of sera ( n = 25) reacted with many proteins, whereas for children >5 years old ( n = 120), 70% of samples reacted with many proteins. Reactivity was decreased by absorbing sera with C neoformans extracts or by preincubating blots with sera from experimentally infected but not from control rats. Reactivity to C neoformans proteins did not correlate with reactivity to C albicans proteins, which was common in sera from children between the ages of 1.1 and 2 years. Cryptococcal polysaccharide was detected at a titer of 1:16 (∼10 ng/mL) in the sera of 1 child, a 5.6-year-old boy who presented to the emergency department with vomiting. Conclusions. Our findings provide both indirect and direct evidence of C neoformans infection in immunocompetent children. Our results indicate that C neoformans infects a majority of children living in the Bronx after 2 years old. These results are consistent with several observations: the ubiquitous nature of C neoformans in the environment, including its association with pigeon excreta; the large number of pigeons in urban areas; and the increased likelihood of environmental exposure for children once they have learned to walk. The signs and symptoms associated with C neoformans infection in immunocompetent children remained to be determined. Primary pulmonary cryptococcosis may be asymptomatic or produce symptoms confused with viral infections and, therefore, not recognized as a fungal infection. Our results suggest that the low incidence of symptomatic cryptococcal disease in children with AIDS is not a result of lack of exposure to C neoformans . These findings have important implications for C neoformans pathogenesis and the development of vaccine strategies.

Missed Opportunities for Perinatal HIV Prevention Among HIV-Exposed Infants Born 1996–2000, Pediatric Spectrum of HIV Disease Cohort

Abstract: Objective. Despite dramatic reductions in perinatal human immunodeficiency virus (HIV) transmission in the United States, obstacles to perinatal HIV prevention that include lack of prenatal care; failure to test pregnant women for HIV before delivery; and lack of prenatal, intrapartum, or neonatal antiretroviral (ARV) use remain. The objective of this study was to describe trends in perinatal HIV prevention methods, perinatal transmission rates, and the contribution of missed opportunities for perinatal HIV prevention to perinatal HIV infection. Methods. We analyzed data obtained from infant medical records on 4755 HIV-exposed singleton deliveries in 1996–2000, from 6 US sites that participate in the Centers for Disease Control and Prevention’s Pediatric Spectrum of HIV Disease Project. HIV-exposed deliveries refer to deliveries in which the mother was known to have HIV infection during the pregnancy. Results. Of the 4287 women with data on prenatal care, 92% had prenatal care. From 1996 to 2000, among the 3925 women with prenatal care, 92% had an HIV test before delivery; the use of prenatal zidovudine (ZDV) alone decreased from 71% to 9%, and the use of prenatal ZDV with other ARVs increased from 6% to 70%. Complete data on maternal and neonatal ARVs were available for 3284 deliveries. Perinatal HIV transmission was 3% in 1651 deliveries with prenatal ZDV in combination with other ARVs, intrapartum ZDV, and neonatal ZDV; 6% in 1111 deliveries with prenatal, intrapartum, and neonatal ZDV alone; 8% in 152 deliveries with intrapartum and neonatal ZDV alone; 14% of 73 deliveries with neonatal ZDV only started within 24 hours of birth; and 20% in 297 deliveries with no prenatal, intrapartum, and neonatal ARVs. Complete data on prenatal events were available in 328 HIV-infected and 3258 HIV-uninfected infants. A total of 56% of mothers of HIV-infected infants had missed opportunities for perinatal HIV prevention versus 16% of mothers of HIV-uninfected infants. Forty-four percent of the infected infants were born to mothers who had prenatal care, a prenatal HIV diagnosis, and documented prenatal ARV therapy. Seventeen percent of women with reported illicit drug use had no prenatal care versus 3% of women with no reported drug use. In a multivariate analysis, maternal illicit drug use was significantly associated with lack of prenatal care. In a multivariate analysis, year of infant birth and the combination of lack of maternal HIV testing before delivery and lack of prenatal antiretroviral therapies were significantly associated with perinatal HIV transmission. Conclusions. Missed opportunities for perinatal HIV prevention contributed to more than half of the cases of HIV-infected infants. Prenatal care and HIV testing before delivery are major opportunities for perinatal HIV prevention. Illicit drug use was highly associated with lack of prenatal care, and lack of HIV testing before delivery was highly associated with perinatal HIV transmission.

The contribution of melanin to microbial pathogenesis.

Abstract: Summary Melanins are enigmatic pigments that are produced by a wide variety of microorganisms including several species of pathogenic bacteria, fungi and helminthes. The study of melanin is difficult because these pigments defy complete biochemical and structural analysis. Nevertheless, the availability of new reagents in the form of monoclonal antibodies and melanin-binding peptides, combined with the application of various physical techniques, has provided insights into the process of melanization. Melanization is important in microbial pathogenesis because it has been associated with virulence in many microorganisms. Melanin appears to contribute to virulence by reducing the susceptibility of melanized microbes to host defence mechanisms. However, the interaction of melanized microbes and the host is complex and includes immune responses to melanin-related antigens. Production of melanin has also been linked to protection against environmental insults. Interference with melanization is a potential strategy for antimicrobial drug and pesticide development. The process of melanization poses fascinating problems in cell biology and provides a type of pathogenic strategy that is common to highly diverse pathogens.

The Survival Benefits of AIDS Treatment in the United States

Abstract: BACKGROUND As widespread adoption of potent combination antiretroviral therapy (ART) reaches its tenth year, our objective was to quantify the cumulative survival benefits of acquired immunodeficiency syndrome (AIDS) care in the United States. METHODS We defined eras corresponding to advances in standards of human immunodeficiency virus (HIV) disease care, including opportunistic infection prophylaxis, treatment with ART, and the prevention of mother-to-child transmission (pMTCT) of HIV. Per-person survival benefits for each era were determined using a mathematical simulation model. Published estimates provided the number of adult patients with new diagnoses of AIDS who were receiving care in the United States from 1989 to 2003. RESULTS Compared with survival associated with untreated HIV disease, per-person survival increased 0.26 years with Pneumocystis jiroveci pneumonia prophylaxis alone. Four eras of increasingly effective ART in addition to prophylaxis resulted in per-person survival increases of 7.81, 11.05, 11.57, and 13.33 years, compared with the absence of treatment. Treatment for patients with AIDS in care in the United States since 1989 yielded a total survival benefit of 2.8 million years. pMTCT averted nearly 2900 infant infections, equivalent to 137,000 additional years of survival benefit. CONCLUSIONS At least 3.0 million years of life have been saved in the United States as a direct result of care of patients with AIDS, highlighting the significant advances made in HIV disease treatment.

The survival benefits of AIDS treatment in the United States. Commentary

Abstract: Background. As widespread adoption of potent combination antiretroviral therapy (ART) reaches its tenth year, our objective was to quantify the cumulative survival benefits of acquired immunodeficiency syndrome (AIDS) care in the United States. Methods. We defined eras corresponding to advances in standards of human immunodeficiency virus (HIV) disease care, including opportunistic infection prophylaxis, treatment with ART, and the prevention of mother-to-child transmission (pMTCT) of HIV. Per-person survival benefits for each era were determined using a mathematical simulation model. Published estimates provided the number of adult patients with new diagnoses of AIDS who were receiving care in the United States from 1989 to 2003. Results. Compared with survival associated with untreated HIV disease, per-person survival increased 0.26 years with Pneumocystis jiroveci pneumonia prophylaxis alone. Four eras of increasingly effective ART in addition to prophylaxis resulted in per-person survival increases of 7.81, 11.05, 11.57, and 13.33 years, compared with the absence of treatment. Treatment for patients with AIDS in care in the United States since 1989 yielded a total survival benefit of 2.8 million years. pMTCT averted nearly 2900 infant infections, equivalent to 137,000 additional years of survival benefit. Conclusions. At least 3.0 million years of life have been saved in the United States as a direct result of care of patients with AIDS, highlighting the significant advances made in HIV disease treatment.

Mother to child transmission of HIV infection in the era of highly active antiretroviral therapy

Abstract: Background. Very low rates of mother-to-child transmission (MTCT) of human immunodeficiency virus (HIV) are achievable with use of highly active antiretroviral therapy (HAART). We examine risk factors for MTCT in the HAART era and describe infants who were vertically infected, despite exposure to prophylactic MTCT interventions. Methods. Of the 4525 mother-child pairs in this prospective cohort study, 1983 were enrolled during the period of January 1997 through May 2004. Factors examined included use of antiretroviral therapy during pregnancy, maternal CD4 cell count and HIV RNA level, mode of delivery, and gestational age in logistic regression analysis. Results. Receipt of antenatal antiretroviral therapy increased from 5% at the start of the HAART era to 92% in 2001-2003. The overall MTCT rate in this period was 2.87% (95% confidence interval [CI], 2.11%-3.81%), but it was 0.99% (95% CI, 0.32%-2.30%) during 2001-2003. In logistic regression analysis that included 885 mother-child pairs, MTCT risk was associated with high maternal viral load (adjusted odds ratio [AOR], 12.1; P = .003) and elective Caesarean section (AOR, 0.33; P = .04). Detection of maternal HIV RNA was significantly associated with antenatal use of antiretroviral therapy, CD4 cell count, and mode of delivery. Among 560 women with undetectable HIV RNA levels, elective Caesarean section was associated with a 90% reduction in MTCT risk (odds ratio, 0.10; 95% CI, 0.03-0.33), compared with vaginal delivery or emergency Caesarean section. Conclusions. Our results suggest that offering an elective Caesarean section delivery to all HIV-infected women, even in areas where HAART is available, is appropriate clinical management, especially for persons with detectable viral loads. Our results also suggest that previously identified risk factors remain important.

Antifungal Drug Development: Challenges, Unmet Clinical Needs, and New Approaches

Abstract: Invasive, life-threatening fungal infections are an important cause of morbidity and mortality, particularly for patients with compromised immune function. The number of therapeutic options for the treatment of invasive fungal infections is quite limited when compared with those available to treat bacterial infections. Indeed, only three classes of molecules are currently used in clinical practice and only one new class of antifungal drugs has been developed in the last 30 years. Here we summarize the unmet clinical needs of current antifungal therapy, discuss challenges inherent to antifungal drug discovery and development, and review recent developments aimed at addressing some of these challenges.