Search PubMed⌕ Search

Biomedical subjects

A Ross

Publications and source records attributed to A Ross.

At least 73 records · Page 4Linked to original sources
PubMed1999

The burden of mucocutaneous conditions and the association with HIV-1 infection in a rural community in Uganda.

OBJECTIVE: To determine the prevalence of mucocutaneous conditions and their association with HIV-1 infection in a rural community in Uganda. METHODS: In a prospective cohort study, participants were recruited from a large population study and invited to attend a clinic every 3 months for a detailed medical interview and a thorough physical examination. All findings including mucocutaneous findings were coded onto a standard questionnaire. RESULTS: By the end of 1996, 436 participants had provided 1450 person years of observation (pyo); 646 pyo in HIV-positives and 804 pyo in HIV-negatives. Overall, 70% of participants had a skin condition during follow-up, and although skin conditions were significantly more common in HIV-positive subjects, the background level in HIV-negative subjects was high (77.3% and 63.6%, respectively). Herpes zoster, thin/sparse hair, maculo-papular rash and prurigo were significantly more common in the HIV-positives. Kaposi sarcoma, palmar/plantar rash and herpes zoster had positive predictive values for HIV infection of over 80%. Oral conditions were found in over 40% of participants and were significantly more common in HIV-positive subjects. Oral candidiasis and Kaposi sarcoma were significantly more frequent among HIV-positives. CONCLUSION: HIV infection increases the already high burden of mucocutaneous diseases in this rural population. We identified some conditions that are more common in HIV and others that can be used as indicators of HIV infection.

AIDS-Related Opportunistic Infections↗
PubMed1999

Setting up a CLIA-certified laboratory in a student health services clinic.

Performing some laboratory tests on site at a student health service clinic may increase efficiency and cut costs for patients. However, with the passage of the Clinical Laboratory Improvement Amendments (CLIA) of 1988, many laboratories in physician offices and clinics have shut down because of increased regulatory requirements. The personnel in one SHS laboratory found that the guidelines proposed by CLIA help assure quality care and are not prohibitive. In this article, the process of applying for and receiving a CLIA certificate in the student health clinic setting is explored.

Ambulatory Care Facilities↗
PubMed1999

Correlates between hematopoiesis and neuropoiesis: neural stem cells.

There are many parallels between the neuropoietic and lymphohematopoietic systems. The lymphohematopoietic stem/progenitor cell system has been extensively characterized, but there are still major questions relating to the definitive stem cell assay, the structure of the system (i.e., hierarchical versus cell cycle-based), and the nature of differentiation (i.e., stochastic versus deterministic). Recent data have established the existence of an epidermal growth factor (EGF)-responsive neural stem cell in adult mice. We have studied these neural progenitor/stem cells in fetal (day 15) and 2-day postnatal mice and established a single-cell progenitor assay and a variety of putative uni-, bi-, and tripotential stem cells that form in response to EGF. Neurospheres are the EGF-responsive neural units that grow in liquid culture, and we have found that cells derived from these neurospheres express a wide array of cytokines and their receptors. This will provide a window on the hemopoietic progenitor system analogous to that created by the description of in vitro growth of clonal hematopoietic progenitors.

Animals↗
PubMed1999

The relation of parent and provider characteristics to vaccination status of children in private practices and managed care organizations in Maryland.

OBJECTIVES: This study sought to identify provider practices and policies in private pediatric settings that relate to vaccination status, controlling for the characteristics of the children served. METHODS: Vaccination data came from the medical records of 709 randomly selected 2-year-old children at 18 private practices and managed care organizations in Maryland, family data from 466 telephone interviews with the children's parents, and provider characteristics from 18 site questionnaires and 42 individual physician and nurse practitioner questionnaires. Logistic regression and generalized estimating equations were used to estimate the relation of provider characteristics to vaccination status. Three age-appropriate (AA) and two up-to-date (UTD) vaccination status variables characterized successful vaccination. RESULTS: Approximately 70% of the study children were up-to-date by age 2 years for the full vaccination series, excluding hepatitis B vaccine. Family demographic characteristics were the strongest correlates of undervaccination. Neither parents' knowledge and attitudes about immunization nor the children's insurance coverage was statistically related to vaccination status. Site reminder or follow-up systems and provider perceptions about appointment scheduling and receipt of vaccine information from health departments were positively related to vaccination. Concern for liability was associated with a reduced odds of age-appropriate and up-to-date vaccination. CONCLUSIONS: Family demographics strongly correlate with vaccination status; however, they are generally not modifiable. This study's findings encourage providers to operate a tracking system, to remain current on immunization recommendations, to use all clinical encounters to screen and vaccinate children, and to ensure the availability and convenience of vaccination services.

Age Factors↗
PubMed1999

Experimentally induced bovine spongiform encephalopathy did not transmit via goat embryos.

Goats are susceptible to experimental challenge with bovine spongiform encephalopathy (BSE). This study set out to investigate whether the transmission of BSE could occur in goats following the transfer of embryos from experimentally infected donor females into uninfected recipient females. The results showed no evidence of transmissible spongiform encephalopathy disease in any of the offspring which developed from embryos from infected donors, nor indeed in any of the recipient females used as surrogate dams. In addition, there was no indication of experimental BSE spreading as either a venereal infection to males used in mating or by maternal transmission to offspring born naturally to experimentally infected donors, although numbers were small.

Animals↗
PubMed1999

Developmental regulation of Bcl-2 family protein expression in the involuting mammary gland.

Epithelial cells within the mammary gland undergo developmental programmes of proliferation and apoptosis during the pregnancy cycle. After weaning, secretory epithelial cells are removed by apoptosis. To determine whether members of the Bcl-2 gene family could be involved in regulating this process, we have examined whether changes in their expression occur during this developmental apoptotic program in vivo. Bax and Bcl-x were evenly expressed throughout development. However, expression of Bak and Bad was increased during late pregnancy and lactation, and the proteins were present during the time of maximal apoptotic involution. Thereafter, their levels declined. In contrast, Bcl-w was expressed in pregnancy and lactation but was downregulated at the onset of apoptosis. Bcl-2 was not detected in lactating or early involuting mammary gland. Thus, the pro-apoptotic proteins Bax, Bak and Bad, as well as the death-suppressors Bcl-x, Bcl-2 and Bcl-w, are synthesised in mouse mammary gland, and dynamic changes in the expression profiles of these proteins occurs during development. To determine if changes in Bak and Bcl-w expression could regulate mammary apoptosis, their effect on cultured mouse mammary epithelial cells was examined in transient transfection assays. Enforced expression of Bak induced rapid mammary apoptosis, which could be suppressed by coexpression of Bcl-w. In extracts of mammary tissue in vivo, Bak heterodimerized with Bcl-x whereas Bax associated with Bcl-w, but Bak/Bcl-w heterodimers were not detected. Thus, Bak and Bcl-w may regulate cell death through independent pathways. These results support a model in which mammary epithelial cells are primed for apoptosis during the transition from pregnancy to lactation by de novo expression of the death effectors Bak and Bad. It is suggested that these proteins are prevented from triggering apoptosis by anti-apoptotic Bcl-2 family proteins until involution, when the levels of Bcl-w decline. Our study provides evidence that regulated changes in the expression of cell death genes may contribute to the developmental control of mammary apoptosis.

Animals↗
PubMed1999

Characteristics of nurse-midwife patients and visits, 1991.

OBJECTIVES: This study describes the patient populations served by and visits made to certified nurse-midwives (CNMs) in the United States. METHODS: Prospective data on 16,729 visits were collected from 369 CNMs randomly selected from a 1991 population survey. Population estimates were derived from a multistage survey design with probability sampling. RESULTS: We estimated that approximately 5.4 million visits were made to nearly 3000 CNMs nationwide in 1991. Most visits involved maternity care, although fully 20% were for care outside the maternity cycle. Patients considered vulnerable to poor access or outcomes made 7 of every 10 visits. CONCLUSIONS: Nurse-midwives substantially contribute to the health care of women nationwide, especially for vulnerable populations.

Adolescent↗
PubMed1998

Lung epithelial cells are a major site of murine gammaherpesvirus persistence.

It is currently believed that latently infected, resting B lymphocytes are central to gammaherpesvirus persistence, whereas mucosal epithelial cells are considered nonessential. We have readdressed the question of nonlymphoid persistence using murine gammaherpesvirus 68 (MHV-68). To dissect lymphoid from nonlymphoid persistence, we used microMT transgenic mice that are defective in B cells. MHV-68 DNA persisted in the lungs of intact and B cell-deficient mice. Both episomal and linear forms of the virus genome were present in lungs, implying the presence of both latency and productive replication. In situ hybridization for virus tRNA transcripts revealed latent MHV-68 in pulmonary epithelial cells. Infectious virus was recovered from the lungs of microMT mice after T cell depletion, showing that the persisting virus DNA was reactivatable. Finally, using adoptive transfer of B cells into B cell-deficient mice, it was shown that virus persisting in lungs seeded splenic B cells, and virus resident in the spleen seeded the lungs. These results show that mucosal epithelia can act as a nonlymphoid reservoir for gammaherpesvirus persistence, and that there is a two-way movement of virus between lymphoid and nonlymphoid compartments during persistence.

Animals↗
PubMed1998

Early manifestations (pre-AIDS) of HIV-1 infection in Uganda.

OBJECTIVES: To describe the early manifestations of HIV-1 infection before the development of AIDS, in a rural Ugandan population. METHODS: Three monthly follow-up of HIV-1-infected and uninfected participants in an HIV-1 natural history cohort from the start of the cohort in 1990 to the end of 1996. RESULTS: A total of 107 persons with prevalent infection and 104 persons with incident infection were enrolled. Eighty (75%) prevalent and 89 (86%) incident individuals were asymptomatic on enrollment. Of the 91 persons with incident infection seen within 2 years of their estimated date of seroconversion, 51% [95% confidence interval (CI), 40-61] were still asymptomatic 2 years after seroconversion. At 4 and 5 years after seroconversion, only 26% (95% CI, 17-36) and 11% (95% CI, 4-22), respectively, remained asymptomatic. A total of 89 participants entered World Health Organization (WHO) stage 2, and their main stage-defining conditions were weight loss <10% (and > 5%) and minor mucocutaneous manifestations. The median CD4 lymphocyte count for participants entering WHO stage 2 was 516 x 10(6) cells/l (interquartile range, 360-884 x 10(6)/l). A total of 94 participants entered WHO stage 3 and the main reasons were weight loss >10%, unexplained chronic diarrhoea, fever for more than 1 month, and severe bacterial infection. The median CD4 lymphocyte count for participants entering WHO stage 3 was 428 x 10(6) cells/l (interquartile range, 276-736 x 10(6)/l). The rates of all conditions reported under the WHO staging system were significantly more frequent in HIV-positive persons than HIV-negative controls with the exception of fever for more than 1 month and oral hairy leukoplakia (which was seen in only three individuals). CONCLUSION: These are the first data from a non-selected African population describing the early manifestations of HIV infection. The main early manifestations were weight loss, minor mucocutaneous features, chronic diarrhoea, chronic fever and severe bacterial infections. The apparent rapid development of HIV-related signs and symptoms is probably indicative of the high background level of these conditions in our study area, as reflected by the rates of these conditions in the HIV-negative controls.

Adult↗
PubMed1998

Primary care physician compensation method in medical groups: does it influence the use and cost of health services for enrollees in managed care organizations?

CONTEXT: Growth of at-risk managed care contracts between health plans and medical groups has been well documented, but less is known about the nature of financial incentives within those medical groups or their effects on health care utilization. OBJECTIVE: To test whether utilization and cost of health services per enrollee were influenced independently by the compensation method of the enrollee's primary care physician. DESIGN: Survey of medical groups contracting with selected managed care health plans, linked to 1994 plan enrollment and utilization data for adult enrollees. SETTING: Medical groups, major managed care health plans, and their patients/enrollees in the state of Washington. STUDY PARTICIPANTS: Sixty medical groups in Washington, 865 primary care physicians (internal medicine, pediatrics, family practice, or general practice) from those groups and affiliated with 1 or more of 4 managed care health plans, and 200 931 adult plan enrollees. INTERVENTION: The effect of method of primary care physician's compensation on the utilization and cost of health services was analyzed by weighted least squares and random effects regression. MAIN OUTCOME MEASURES: Total visits, hospital days, and per member per year estimated costs. RESULTS: Compensation method was not significantly (P>.30) related to utilization and cost in any multivariate analyses. Patient age (P<.001), female gender (P<.001), and plan benefit level (P<.001) were significantly positively related to visits, hospital days, and per member per year costs. The primary care physician's age was significantly negatively related (P<.001) to all 3 dependent measures. CONCLUSIONS: Compensation method was not significantly related to use and cost of health services per person. Enrollee, physician, and health plan benefit factors were the prime determinants of utilization and cost of health services.

Capitation Fee↗
PubMed1998

Effectiveness of pediatric practice consultation on missed opportunities for immunization.

OBJECTIVE: To evaluate the effectiveness of pediatric practice consultation in reducing missed-opportunity rates at eight pediatric sites in Baltimore, Maryland. The overarching goal was to decrease the occurrence of missed opportunities from 33% to 15% for the first, second, and third diphtheria and tetanus toxoids and pertussis vaccines during visits at which children were eligible for the vaccines. DESIGN: The effect of an in-office educational program alone at four sites is compared with the educational program and a consultation on office vaccination practices at four matched sites. All eight sites received a small grant ($2,000) to fund practice changes. The medical records of children making visits before and after the interventions were audited to determine missed-opportunity rates. The policies and operations and the knowledge, attitudes, and practices of physicians and nurse practitioners at each site were also assessed. RESULTS: The four education-consultation sites experienced a statistically significant 14% net reduction in the missed-opportunity rate relative to the education-only sites. This positive effect, however, was largely due to an increase in missed opportunities at one education-only site. There was a 10% increase in the missed-opportunity rate among the education-only sites and a 4% decrease among the education-consultation sites; neither change was statistically significant. Two of the three sites that reduced missed opportunities were matched health maintenance organizations (HMOs). Shortly after the interventions, both HMOs implemented tracking and follow-up information systems, which were planned before the interventions. CONCLUSIONS: There is no evidence that either the educational program alone or the educational program and consultation combination reduced missed opportunities. The findings suggest that improved tracking and follow-up data systems and vaccination of children at sick visits may reduce missed opportunities.

Baltimore↗
PubMed1998

A hydrophobic interaction site for lysozyme binding to polyethylene glycol and model contact lens polymers.

Proton nuclear magnetic resonance (1H-NMR) spectroscopy is used to identify a preferred binding site for uncharged hydrophilic polymers on the surface of hen egg-white lysozyme. Chemical shift titrations show that exchangeable proton signals from amino acids Arg-61, Trp-62, Trp-63, Arg-73, Lys-96 and Asp-101 are selectively perturbed upon binding of poly(ethylene oxide), poly(ethylene glycol) and poly(ethylene-co-propylene oxide). The greatest binding-induced chemical shift changes are observed for Trp-62, Arg-61 and Arg-73 at the edge of the active site cleft of the protein, consistent with a predominantly hydrophobic interaction mode involving the polymer ethylene moieties. The more hydrophilic species poly(dihydroxypropyl methacrylate) causes similar but substantially smaller chemical shift effects than the other polymers, confirming the nature of the interaction. A dissociation constant of 76+/-5 mM is determined for the poly(ethylene glycol)-lysozyme complex. The relatively low affinity of the protein-polymer interactions compared to oligosaccharide substrate binding suggests that lysozyme activity is minimally affected by these materials.

Binding Sites↗
PubMed1998

Maternal satisfaction with labour analgesia.

Satisfaction with childbirth is a multidimensional issue, of which analgesia is but one component. The importance of analgesia as a contribution to overall satisfaction has been recognized increasingly in the last 50 years, but improvement in quality of available analgesia has not always resulted in commensurate improvement in satisfaction. Satisfaction by its very nature has proved to be difficult both to define and to quantify, and no reliable standards of measurement have been accepted. Pain relief in childbirth is subject to many social and cultural modifiers, which continue to change. Control of pain rather than absolute amelioration is seen by many to provide greater satisfaction. Analgesia issues still do not figure prominently in the overall satisfaction of the birthing process for the vast majority of women, despite the availability of and demand for improved methods of relief. The interpersonal relationships established between patient and healthcare providers may ultimately be of more importance in the determination of satisfaction with management.

Analgesia, Obstetrical↗
PubMed1998

Clonidine suppression test revisited.

BACKGROUND: The diagnosis of pheochromocytoma may be difficult because the clinical picture is variable. OBJECTIVE: The purpose of this paper is to report our experience and to review the published data on the diagnostic significance and risks of the clonidine suppression test in the diagnosis of pheochromocytoma. PATIENTS AND METHODS: 114 patients were evaluated for pheochromocytoma using the clonidine suppression test. RESULTS: The diagnosis was established in four patients. Overall accuracy of the test in our own series was 98% when the normal response to clonidine was defined as total plasma catecholamines of less than 500 ng/L, or less than 70% of the baseline value. No serious complication was noted. CONCLUSION: Our data and the published series demonstrate that the clonidine suppression test is accurate and safe in patients with suspected pheochromocytoma.

Adrenal Gland Neoplasms↗
PubMed1998

Causes of death in a rural, population-based human immunodeficiency virus type 1 (HIV-1) natural history cohort in Uganda.

BACKGROUND: While human immunodeficiency virus (HIV)-related causes of death have been well documented in developed countries, in Africa data are scanty and mainly based on autopsy studies from city hospitals which are highly selective and may not represent causes of HIV-associated deaths in the general population. This study, from a rural population, describes the causes of death in HIV-positive people and their HIV-negative controls. METHODS: A natural history cohort comprising HIV-1 infected participants and HIV-negative controls was established in rural Uganda in 1990. Causes of death were determined by reviewing the premorbid clinical and laboratory findings and from information obtained from relatives. Blindness to the deceased's HIV serostatus was maintained throughout. RESULTS: In all, 78 deaths occurred over a 6-year period: 63 deaths occurred in the HIV-positive cases (53 prevalent and 10 incident cases) and 15 deaths in the HIV-negative controls. Of the prevalent cases, 56%, and 9% the incident cases enrolled died, compared with 7% of the HIV-negative controls. Of the 55 HIV-positive cases with sufficient data to establish cause of death, 52 (95%) were assessed as having HIV-associated deaths and 48 (87%) died in WHO stage 4 (AIDS). The main causes of death were wasting syndrome (31%), chronic diarrhoea (22%), cryptococcal meningitis (13%) and chest infection (11%). CONCLUSIONS: Our results represent an unbiased selection of deaths in a rural area. The HIV-positive cases have high death rates and die of HIV-related pathologies. The main causes of death reflect the WHO clinical case definition of AIDS. Cryptococcal meningitis is also a common cause of death in this population.

Adult↗