HIV-1 Envelope Subregion Length Variation during Disease Progression

The V3 loop of the HIV-1 Env protein is the primary determinant of viral coreceptor usage, whereas the V1V2 loop region is thought to influence coreceptor binding and participate in shielding of neutralization-sensitive regions of the Env glycoprotein gp120 from antibody responses. The functional properties and antigenicity of V1V2 are influenced by changes in amino acid sequence, sequence length and patterns of N-linked glycosylation. However, how these polymorphisms relate to HIV pathogenesis is not fully understood. We examined 5185 HIV-1 gp120 nucleotide sequence fragments and clinical data from 154 individuals (152 were infected with HIV-1 Subtype B). Sequences were aligned, translated, manually edited and separated into V1V2, C2, V3, C3, V4, C4 and V5 subregions. V1-V5 and subregion lengths were calculated, and potential N-linked glycosylation sites (PNLGS) counted. Loop lengths and PNLGS were examined as a function of time since infection, CD4 count, viral load, and calendar year in cross-sectional and longitudinal analyses. V1V2 length and PNLGS increased significantly through chronic infection before declining in late-stage infection. In cross-sectional analyses, V1V2 length also increased by calendar year between 1984 and 2004 in subjects with early and mid-stage illness. Our observations suggest that there is little selection for loop length at the time of transmission; following infection, HIV-1 adapts to host immune responses through increased V1V2 length and/or addition of carbohydrate moieties at N-linked glycosylation sites. V1V2 shortening during early and late-stage infection may reflect ineffective host immunity. Transmission from donors with chronic illness may have caused the modest increase in V1V2 length observed during the course of the pandemic

Religious Characteristics of U.S. Physicians: A National Survey

BACKGROUND: Patients' religious commitments and religious communities are known to influence their experiences of illness and their medical decisions. Physicians are also dynamic partners in the doctor–patient relationship, yet little is known about the religious characteristics of physicians or how physicians' religious commitments shape the clinical encounter. OBJECTIVE: To provide a baseline description of physicians' religious characteristics, and to compare physicians' characteristics with those of the general U.S. population. DESIGN/PARTICIPANTS: Mailed survey of a stratified random sample of 2,000 practicing U.S. physicians. Comparable U.S. population data are derived from the 1998 General Social Survey. MEASUREMENTS/RESULTS: The response rate was 63%. Fifty-five percent of physicians say their religious beliefs influence their practice of medicine. Compared with the general population, physicians are more likely to be affiliated with religions that are underrepresented in the United States, less likely to say they try to carry their religious beliefs over into all other dealings in life (58% vs 73%), twice as likely to consider themselves spiritual but not religious (20% vs 9%), and twice as likely to cope with major problems in life without relying on God (61% vs 29%). CONCLUSIONS: Physicians' religious characteristics are diverse and they differ in many ways from those of the general population. Researchers, medical educators, and policy makers should further examine the ways in which physicians' religious commitments shape their clinical engagements