Biomedical subjects

William G Cumberland

Publications and source records attributed to William G Cumberland.

6 recordsLinked to original sources

PubMed2006

Hemorheologic abnormalities associated with HIV infection: in vivo assessment of retinal microvascular blood flow.

PURPOSE: To evaluate retinal microvascular blood flow in human immunodeficiency virus (HIV)-infected individuals using scanning laser Doppler flowmetry (SLDF) and to seek correlations between flow and various laboratory measures that may predict alterations in flow. METHODS: The Heidelberg Retina Flowmeter and SLDF software were used to acquire in vivo retinal blood flow data from 24 HIV-infected individuals and 16 HIV-negative control subjects. In each subject, separate scans were performed in each of six retinal regions: nasal parapapillary retina; macula; and the superior, nasal, inferior, and temporal periphery. Erythrocyte aggregation (assessed in vitro by a fully automatic erythrocyte aggregometer and by zeta sedimentation ratio [ZSR, a hematocrit-independent sedimentation rate]), serum fibrinogen level, plasma viscosity, and leukocyte rigidity (assessed in vitro with a cell transit analyzer) were compared with flow in selected regions. RESULTS: Flow was significantly higher in the periphery (superior, nasal, inferior, temporal) than in the posterior retina (nasal parapapillary retina, macula). Flow was highest in the temporal periphery for both HIV-infected subjects and control subjects. Flow in the posterior retina was significantly lower in HIV-infected subjects than in control subjects (P < 0.0001). Among HIV-infected individuals, flow in the macula correlated negatively with ZSR (r = -0.397, P = 0.0547) and leukocyte rigidity (r = -0.505, P = 0.0119). CONCLUSIONS: Microvascular blood flow in the posterior retina is reduced in HIV-infected individuals. Both increased erythrocyte aggregation and increased leukocyte rigidity contribute to this hemorheologic abnormality.

Adult↗

PubMed2005

Overweight in urban, low-income, African American and Hispanic children attending Los Angeles elementary schools: research stimulating action.

OBJECTIVE: This study was undertaken to establish the prevalence and severity of nutritional problems among low-income children of elementary school age in the Los Angeles Unified School District (LAUSD) in order to collect baseline data to inform policy-makers. DESIGN AND METHODS: A cross-sectional survey of children in 14 elementary schools was conducted from January to June, 1998. Nine hundred and nineteen children were measured and interviewed. The planning, design and data analysis were carried out in collaboration with key LAUSD policy-makers. RESULTS: More than 35% of the sample was classified as being at risk for overweight or overweight according to body mass index. CONCLUSION: There is a high prevalence of children who are at risk for overweight or who are overweight in Los Angeles. This finding has triggered the development of multiple school-based intervention programmes.

Black or African American↗

PubMed2005

A queueing model for chronic recurrent conditions under panel observation.

In many chronic conditions, subjects alternate between an active and an inactive state, and sojourns into the active state may involve multiple lesions, infections, or other recurrences with different times of onset and resolution. We present a biologically interpretable model of such chronic recurrent conditions based on a queueing process. The model has a birth-death process describing recurrences and a semi-Markov process describing the alternation between active and inactive states, and can be fit to panel data that provide only a binary assessment of the active or inactive state at a series of discrete time points using a hidden Markov approach. We accommodate individual heterogeneity and covariates using a random effects model, and simulate the posterior distribution of unknowns using a Markov chain Monte Carlo algorithm. Application to a clinical trial of genital herpes shows how the method can characterize the biology of the disease and estimate treatment efficacy.

Algorithms↗

PubMed2005

Respecting and protecting our relationships: a community research HIV prevention program for teen fathers and mothers.

This article describes a two-phase community and academic collaboration funded by the California Collaborative Research Initiative to develop and test the feasibility of an innovative HIV prevention program relevant to the needs of the population of inner-city Latino teen parenting couples and realistic for implementation in community settings. The article describes (a) the identification of special issues that needed to be addressed before formation of a productive academic-community-based organization research partnership, including integrating a dominant theoretical model used in health education with principles of practice derived from clinical experience; (b) the first phase of the project that helped to inform the development of the HIV prevention program for couples; (c) examples from the intervention pilot study (Phase 2) that illustrate both the intervention strategies and the young participants' responses to the curriculum; and (d) the feasibility of program implementation and evaluation in a community setting.

Adolescent↗

PubMed2002

An assessment of polymorphonuclear leukocyte rigidity in HIV-infected individuals after immune recovery.

PURPOSE: To determine whether polymorphonuclear leukocytes (PMNs) remain rigid after immune reconstitution in human immunodeficiency virus (HIV)-infected individuals with a history of severe immunosuppression. METHODS: PMN rigidity was measured in vitro in three groups: (1) HIV-infected individuals with a history of CD4+ T-lymphocyte counts of less than 50/microL, but with current counts of more than 200/microL attributable to potent antiretroviral therapy (group 1); (2) HIV-infected individuals whose CD4+ T-lymphocyte counts had always been more than 200/microL (group 2); and (3) HIV-negative control subjects. Rigidity was determined with a cell transit analyzer (containing a micropore filter with 30 identical, 8-microm diameter pores), representing a simple in vitro model of a capillary bed. A longer PMN pore transit time reflects increased PMN rigidity. RESULTS: PMN transit time (median) in group 1 (n = 11) was 3.34 ms, in group 2 (n = 9) was 3.19 ms, and in control subjects (n = 15) was 2.66 ms. PMN rigidity was significantly greater in groups 1 (P = 0.014) and 2 (P = 0.046) than in control subjects (Wilcoxon rank-sum test). A significant difference was not identified between groups 1 and 2 (P = 0.518). CONCLUSIONS: The increased PMN rigidity known to occur in severely immunosuppressed HIV-infected individuals persists after immune reconstitution. Furthermore, PMN rigidity is increased in those HIV-infected individuals who do not have a history of severe immunosuppression. Because PMN rigidity can alter microvascular blood flow, HIV-infected individuals may remain at risk for retinal vascular damage in the era of potent antiretroviral therapy.

Adult↗

PubMedDate not supplied

Project CHARM: an HIV prevention program for adolescent mothers.

Effects were examined of a human immunodeficiency virus (HIV) prevention program for adolescent mothers offered in pregnant minor and parenting programs in Los Angeles County. The sample included young women (N = 497) of predominantly poor, Latina backgrounds who had complete data from baseline to the one-year follow-up. The treatment group demonstrated statistically significant improvements in AIDS knowledge and intentions to use condoms, and fewer sex partners at the six-month follow-up as compared to the control group. Findings related to the effects of the intervention on theoretical variables provide some support for selected concepts from Social Cognitive Theory and the Theory of Reasoned Action.

Adolescent↗