Faculty Bibliography

BACKGROUND: Simple biomarkers are required to identify TB in both HIV(-)TB(+) and HIV(+)TB(+) patients. Earlier studies have identified the M. tuberculosis Malate Synthase (MS) and MPT51 as immunodominant antigens in TB patients. One goal of these investigations was to evaluate the sensitivity and specificity of anti-MS and -MPT51 antibodies as biomarkers for TB in HIV(-)TB(+) and HIV(+)TB(+) patients from a TB-endemic setting. Earlier studies also demonstrated the presence of these biomarkers during incipient subclinical TB. If these biomarkers correlate with incipient TB, their prevalence should be higher in asymptomatic HIV(+) subjects who are at a high-risk for TB. The second goal was to compare the prevalence of these biomarkers in asymptomatic, CD4(+) T cell-matched HIV(+)TB(-) subjects from India who are at high-risk for TB with similar subjects from US who are at low-risk for TB. METHODS AND RESULTS: Anti-MS and -MPT51 antibodies were assessed in sera from 480 subjects including PPD(+) or PPD(-) healthy subjects, healthy community members, and HIV(-)TB(+) and HIV(+)TB(+) patients from India. Results demonstrate high sensitivity (approximately 80%) of detection of smear-positive HIV(-)TB(+) and HIV(+)TB(+) patients, and high specificity (>97%) with PPD(+) subjects and endemic controls. While approximately 45% of the asymptomatic HIV(+)TB(-) patients at high-risk for TB tested biomarker-positive, >97% of the HIV(+)TB(-) subjects at low risk for TB tested negative. Although the current studies are hampered by lack of knowledge of the outcome, these results provide strong support for the potential of these biomarkers to detect incipient, subclinical TB in HIV(+) subjects. CONCLUSIONS: These biomarkers provide high sensitivity and specificity for TB diagnosis in a TB endemic setting. Their performance is not compromised by concurrent HIV infection, site of TB and absence of pulmonary manifestations in HIV(+)TB(+) patients. Results also demonstrate the potential of these biomarkers for identifying incipient subclinical TB in HIV(+)TB(-) subjects at high-risk for TB

To provide quantitative evidence of the impact on people of a neighboring metropolitan airport, La Guardia Airport (LGA) in New York City, (1) airborne particulate matter (PM) was measured to determine whether concentration differences could be detected between homes that are upwind and downwind of the airport; (2) 24-hr noise measurements were made in 12 homes near the airport; and (3) the impact of noise was assessed by a Community Wellness and Health Promotion Survey. Particulate matter concentrations were higher during active airport operating hours than during nonoperating hours, and the percent increase varied inversely with distance from the airport. Hourly differences between paired upwind and downwind sites were not remarkable. Residents living near the airport were exposed to noise levels as much as four times greater than those experienced by residents in a quiet, comparison home. Impulse noise events were detected from both aircraft and vehicular traffic. More than 55% of the people living within the flight path were bothered by aircraft noise, and 63% by highway noise; these were significantly higher percentages than for residents in the nonflight area. The change in PM concentrations with distance during operating compared with nonoperating hours; traffic-related impulse noise events; and the elevated annoyance with highway noise, as well as aircraft noise among residents in the flight path area, show airport-related motor vehicle traffic to be a major contributor to the negative impact of airports on people in the surrounding communities

Drinking arsenic-contaminated water is associated with increased risk of neoplasias of the skin, lung, bladder and possibly other sites, as well as other diseases. Earlier, we showed that human lymphoblast lines from different normal unexposed donors showed variable sensitivities to the toxic effects of arsenite. In the present study, we used microarray analysis to compare the basal gene expression profiles between two arsenite-resistant (GM02707, GM00893) and two arsenite-sensitive lymphoblast lines (GM00546, GM00607). A number of genes were differentially expressed in arsenite-sensitive and arsenite-resistant cells. Among these, gamma-glutamyltranspeptidase 1 (GGT1) and NF kappa B inhibitor-epsilon (NFKBIE) showed higher expression levels in arsenite-resistant cells. RT-PCR analysis with gene-specific primers confirmed these results. Reduction of GGT1 expression level in arsenite-resistant lymphoblasts with GGT1-specific siRNA resulted in increased cell sensitivity to arsenite. In conclusion, we have demonstrated for the first time that expression levels of GGT1 and possibly NFKBIE might be useful as biomarkers of genetic susceptibility to arsenite. Expression microarrays can thus be exploited for identifying additional biomarkers of susceptibility to arsenite and to other toxicants

Quantitative cancer incidence data exist for various laboratory animal models, but little of this information is usable for estimating human risks, primarily because of uncertainties about possible mechanistic differences among species. Acceptance and utilization of animal data for human risk assessment will require a much better understanding of the comparative underlying mechanisms than now exists. A dual-lesion, radiation-track model in rat skin has proven to be consistent with tumor induction data with respect to acute radiation doses ranging from 0.5 up to 10 Gy and higher, and average LETs ranging from 0.34 to 150 keV microm(-1) according to the form neoplastic risk (D,L) = CLD + BD2. A recent result with the 56Fe ion beam showed dose-response consistency for malignant (carcinomas) and benign (fibromas) tumor induction with earlier results utilizing argon and neon ion beams. A discrepancy between the model and experiment was found indicating that proportionality of cancer yield with LET did not occur at 150 versus 125 keV microm(-1), i.e. tumor yield did not increase in spite of a 20% increase of LET, which suggests that a LET response maximum exists at or within this dose range. Concordance between the model and tumor induction data in rat skin implies that potential intervening complexities of carcinogenic progression fail to obscure the basic radiobiological assumptions underpinning the model. Gene expression microarray analysis shows that vitamin A inhibits the expression of about 80% of the inflammation-related genes induced by the radiation and prevents about 46% of the neoplasms associated with 56Fe ion radiation without appearing to interfere with the underlying dose and LET response patterns. Further validation is needed, but the model has the potential to provide quantitative estimates of cancer risk as a function of dose and LET for almost any type of radiation exposure and even for combinations of different radiations provided only three empirical parameters can be established for each type of radiation and organ system.

OBJECTIVES:: To test the hypothesis that in comparison with those with shorter risk duration, individuals with longer HIV risk duration would have reduced susceptibility to HIV-1 infection as measured by CCR5 expression, and to evaluate whether variation in CCR5 expression could be explained by known genetic polymorphisms. DESIGN AND METHODS:: A cross-sectional study of HIV-1 exposed but uninfected men who have sex with men. The risk duration was estimated from self-reported years since first receptive anal intercourse. CCR5 expression on peripheral blood CD4+ monocytes and T cells was determined by flow cytometry. The CCR5-Delta32 mutation and polymorphisms in the CCR5 promoter and CCR2 as well as the copy number of CCL3L1 were analyzed by polymerase chain reaction. Plasma levels of MIP-1alpha (CCL3), MIP-1beta (CCL4) and RANTES (CCL5) were also measured. As risk duration varied with age, analyses were restricted to 67 individuals aged 30-49 years. RESULTS:: Multiple linear regression analyses, adjusted for age and race, showed a significant negative association between HIV risk duration and CCR5 expression on monocytes (P = 0.01), and in a separate model, a similar negative association with CCR5 expression on T cells (P = 0.03). Low CCR5 expression was attributable mainly to CCR5-Delta32 heterozygosity and the CCR5-59029G allele. CONCLUSIONS:: We confirmed a role for reduced CCR5 expression in HIV-1 resistance. CCR5-Delta32 heterozygosity and the CCR5-59029G allele were significant predictors of low CCR5 expression. Individuals with high CCR5 expression who resisted infection despite long HIV risk duration form an interesting group within which to search for additional mechanisms of resistance to HIV infection

The majority of global human immunodeficiency virus infections are caused by viruses characterized by a GPGQ motif at the tip of the V3 loop. Characterization of anti-V3 monoclonal antibodies (MAbs) that neutralize isolates with the GPGQ V3 motif is an important step in designing vaccines that will induce such Abs. Consequently, seven human anti-V3 MAbs derived from the cells of individuals infected with non-B-subtype viruses (anti-V3(non-B) MAbs) were generated from the cells of individuals from Africa infected with circulating recombinant forms CRF02_AG, CRF09_cpx, and CRF13_cpx, each of which contains a subtype A env gene. Sequence analysis of plasma viruses revealed a GPGQ motif at the apex of the V3 loop from six of the seven subjects and a GPGR motif from one subject. The MAbs were selected with fusion proteins (FP) containing V3(92UG037.8) or V3(JR-CSF) from subtype A or B, respectively. In virus binding assays, five of the seven (71%) anti-V3(non-B) MAbs bound to V3-FPs from both subtype A and subtype B, while only four of the nine (44%) anti-V3(B) MAbs recognized both V3-FPs. Using two neutralization assays, both the anti-V3(non-B) and the anti-V3(B) MAbs neutralized subtype B viruses with similar activities, while the anti-V3(non-B) MAbs exhibited a tendency toward both increased potency and breadth of neutralization against non-B viruses compared to anti-V3(B) MAbs. Statistical significance was not achieved, due in large measure to the sizes of the MAb panels, but the overall pattern of data strongly suggests that viruses with the GPGQ motif at the tip of the V3 loop induce anti-V3 Abs with broader cross-neutralizing activity than do viruses with the GPGR motif

The known sequences of HIV-1 viruses have been categorized into subtypes based on the phylogenetic partitioning of their env and gag gene sequences. The env gene encodes the protein gp120, which contains five sequence- variable regions (V1 to V5), of which the V3 loop is of central importance to viral infectivity. The V3 loop consensus sequences of HIV-1 subtype A and C viruses are similar, and more similar to one another than the V3 consensus sequences of any other two HIV-1 subtypes. However, using a position-specific statistical comparison, we found that the V3 region of these two subtypes is statistically distinct (p = approximately 0.0). (The p-value calculated to the lowest limit of representation on the computer used to run the calculation. This lowest limit was 10(16). Although theoretically a p-value cannot be equal to 0.0, the p-value for the comparisons in question can be intuitively considered to be extremely small, or approximately 0.0.)

Early pregnancy is a powerful negative risk factor for breast cancer (BCa) in women. Pregnancy also protects rats against induction of BCa by carcinogens such as N-methyl-N-nitrosourea (MNU), making the parous rat a useful model for studying this phenomenon. Smoking during early pregnancy may lead to an increased risk of BCa in later life, possibly attributable to carcinogens in cigarette smoke (CS), or to reversal of the parity-related protection against BCa. To investigate these possibilities, 50-day-old timed first-pregnancy rats were exposed to standardized mainstream CS (particle concentration = 50 mg/m3) or to filtered air (FA) 4 h/day, Day 2-20 of gestation. Age-matched virgin rats were similarly exposed to CS or FA. At age 100 days, the CS or FA-exposed, parous and virgin rats were injected s.c. with MNU (50 mg/kg body wt), or with MNU vehicle. Mammary tumors (MTs) first appeared in virgin rats 9 weeks post-MNU injection. While no MTs were detected in FA-exposed parous rats until 18 weeks post-MNU, MTs appeared in the CS-exposed parous rats as early as 10 wks (P < 0.02). As no MTs developed in CS-exposed rats not injected with MNU, CS did not act as a direct mammary carcinogen. Serum prolactin concentration on Day 19 of pregnancy in CS-exposed dams was reduced by 50% compared with FA-exposed dams (P < 0.005). CS exposure during a pregnancy may thus 'deprotect' rats, enhancing their vulnerability to MNU-induced BCa. Prenatal CS exposure had no detectable effect on the immune responses of the pups examined at 3, 8 or 19 weeks of age. However, prolactin concentration in stomach contents (milk) of 3-day-old pups suckled by CS-exposed dams was decreased when compared with that of FA-exposed dams (P < 0.032). As milk-borne prolactin modulates development of the central nervous and immune systems of neonatal rats, CS exposure of the dams could adversely affect later maturation of these systems by reducing milk prolactin

Human immunodeficiency virus type 1 (HIV-1) circulating recombinant form (CRF) 02_AG is the predominant subtype in Cameroon, even more prevalent than the parental subtypes A and G. An important question that needs to be addressed is whether recombination in HIV-1 infection can lead to the emergence of viruses with biological advantages. The replicative capacity was investigated in peripheral blood mononuclear cells (PBMCs) of 13 R5-tropic primary HIV-1 isolates, including 5 CRF02_AG, 4 subtype A, and 4 subtype G viruses. HIV-1 subtype identity was defined by phylogeny either of the full-length genome or analysis of a combination of segments of the gag, pro, pol, and env genes followed by recombination breakpoint analysis. All viruses were grown on PBMCs for 11 days and culture supernatant was analyzed for reverse transcriptase (RT) activity and p24 production. On day 11 post-infection, CRF02_AG strains had a 1.4-1.9 times higher RT activity and reached a significantly higher level of p24 production than the parental subtypes A and G. Furthermore, the replication rate as measured by p24 production was 1.4 times higher for CRF02_AG strains compared to the subtypes A and G. This study suggests that the recombination event that led to CRF02_AG resulted in a variant with a better replicative capacity than its progenitors. This adaptation could contribute to the broader spread of HIV-1 CRF02_AG leading to its predominance in West Central Africa compared to the lower prevalence of its parental subtypes A and G