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Biomedical subjects

Gregory Glass

Publications and source records attributed to Gregory Glass.

7 recordsLinked to original sources

Quantitative assessment of viable Cryptosporidium parvum load in commercial oysters (Crassostrea virginica) in the Chesapeake Bay.

The epidemiological importance of increasing reports worldwide on Cryptosporidium contamination of oysters remains unknown in relation to foodborne cryptosporidiosis. Thirty market-size oysters (Crassostrea virginica), collected from each of 53 commercial harvesting sites in Chesapeake Bay, MD, were quantitatively tested in groups of six for Cryptosporidium sp. oocysts by immunofluorescent antibody (IFA). After IFA analysis, the samples were retrospectively retested for viable Cryptosporidium parvum oocysts by combined fluorescent in situ hybridization (FISH) and IFA. The mean cumulative numbers of Cryptosporidium sp. oocysts in six oysters (overall, 42.1+/-4.1) were significantly higher than in the numbers of viable C. parvum oocysts (overall, 28.0+/-2.9). Of 265 oyster groups, 221 (83.4%) contained viable C. parvum oocysts, and overall, from 10-32% (mean, 23%) of the total viable oocysts were identified in the hemolymph as distinct from gill washings. The amount of viable C. parvum oocysts was not related to oyster size or to the level of fecal coliforms at the sampling site. This study demonstrated that, although oysters are frequently contaminated with oocysts, the levels of viable oocysts may be too low to cause infection in healthy individuals. FISH assay for identification can be retrospectively applied to properly stored samples.

Animals↗

The effect of deforestation on the human-biting rate of Anopheles darlingi, the primary vector of Falciparum malaria in the Peruvian Amazon.

To examine the impact of tropical rain-forest destruction on malaria, we conducted a year-long study of the rates at which the primary malaria vector in the Amazon, Anopheles darlingi, fed on humans in areas with varying degrees of ecological alteration in the Peruvian Amazon. Mosquitoes were collected by human biting catches along the Iquitos-Nauta road at sites selected for type of vegetation and controlled for human presence. Deforested sites had an A. darlingi biting rate that was more than 278 times higher than the rate determined for areas that were predominantly forested. Our results indicate that A. darlingi displays significantly increased human-biting activity in areas that have undergone deforestation and development associated with road development.

Animals↗

Authorized generics.

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Cooperative Behavior↗

Pharmaceutical patent challenges--time for reassessment?

For nearly 15 years after the passage of the Hatch-Waxman Act in 1984, generics drug companies took little advantage of its provisions, which provided financial incentives to them for challenging the patents of branded pharmaceutical products. However, during the past 3-5 years, generics manufacturers have dramatically increased the number of patent challenges. Although these challenges can certainly benefit consumers and payers, the number of challenges puts many innovator companies at risk, which they argue is detrimental to future R&D spending. If many of the challenges are successful, then the increase in challenges could in turn be detrimental to generics, and the system itself might therefore be due for a re-balance.

Drug Industry↗

Disparities in cognitive functioning by race/ethnicity in the Baltimore Memory Study.

The Baltimore Memory Study is a cohort study of the multilevel determinants of cognitive decline in 50-70-year-old randomly selected residents of specific city neighborhoods. Prior studies have demonstrated that cognitive function differs by race/ethnicity, with lower scores in minorities than in whites, but the underlying basis for these differences is not understood. Studies have differed in the rigor with which they evaluated and controlled for such important confounding variables as socioeconomic status (SES), health-related behaviors, comorbid illnesses, and factors in the physical environment. The goal of this study was to describe differences in neurobehavioral test scores by race/ethnicity, before and after control for a four-dimensional measure of SES and health-related behaviors and health conditions, in a cross-sectional analysis of first visit data. Random samples of households in the study area were selected until enrollment goals were reached. Among the 2,351 persons on whom eligibility was determined, 60.8% were scheduled for an enrollment visit; of these, 1,140 (81.3%) were enrolled and tested. These study participants were 34.3% male and 65.7% female and were from 65 Baltimore, Maryland, neighborhoods. After adjustment for age, sex, and testing technician, there were large and statistically significant differences in neurobehavioral test scores by race/ethnicity, with African-American scores lower than those for whites, for both men and women. After adjustment for individual SES (educational status, household income, household assets, and occupational status), the average difference declined by 25.8%. After additional adjustment for SES, health-related behaviors and health conditions, and blood lead, the average difference declined another 10%, but large differences persisted; African Americans had test scores that averaged 0.43 standard deviation lower than those for whites across all neurobehavioral tests. These differences were present in all cognitive domains, including tests that would not be characterized as susceptible to differential item functioning by race/ethnicity, suggesting that the results are not due to race/ethnicity-associated measurement error.

Black or African American↗

Longitudinal evaluation of an educational intervention for preventing tick bites in an area with endemic lyme disease in Baltimore County, Maryland.

The authors attempted to determine whether a targeted educational intervention in an area with endemic Lyme disease could increase knowledge, positive attitudes, and reported behaviors related to tick bite prevention and consequently decrease tick bites, as measured by a biomarker of tick bites. Between April and September of 1999, 317 subjects in Baltimore County, Maryland, were randomized to receive either tick-related or general health-related educational materials bimonthly through the mail. At each of three clinic visits, participants completed a self-administered questionnaire and provided a serum sample. Anti-recombinant tick calreticulin antibody (ARTCA), measured in ng/ micro l, was used as a biomarker of tick bites. Linear and logistic regression analyses were used to determine 1) whether the educational intervention was associated with a change in knowledge, attitudes, and behaviors (KAB) and 2) whether change in KAB predicted change in ARTCA levels. Proportions of desired responses increased significantly among intervention subjects versus the comparison group on KAB measures related to examining the body for ticks and insect repellent use. Levels of ARTCA were low among all study subjects. Only six of 37 models exhibited a significant relation between change in a KAB variable and change in ARTCA levels over time. The behavioral intervention was associated with an increase in the KAB measures in the intervention group, but this change was not associated with change in ARTCA levels.

Adolescent↗