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Biomedical subjects

L I Gardner

Publications and source records attributed to L I Gardner.

At least 37 records · Page 2Linked to original sources
PubMed1990

Human immunodeficiency virus infections in teenagers. Seroprevalence among applicants for US military service. The Walter Reed Retrovirus Research Group.

Between October 15, 1985, and March 31, 1989, serum specimens from 1 141 164 teenaged youths (aged less than 20 years) who applied for entry into the US military were tested for antibodies to the human immunodeficiency virus. Overall, 393 teenaged applicants were found to be seropositive (prevalence, 0.34 per 1000). Prevalences varied markedly in different geographic locales: less than 0.1 per 1000 throughout the north-central states, compared with greater than 2 per 1000 in urban counties in Maryland, Texas, New York, and the District of Columbia. Overall, rates among teenaged males (345/991 445; prevalence, 0.35 per 1000) and teenaged females (48/150 013; prevalence, 0.32 per 1000) were comparable. The prevalence among black teenaged applicants (1.06 per 1000) was greater than that among white (0.18 per 1000) or Hispanic (0.31 per 1000) teenaged applicants. Infections with the human immunodeficiency virus are not rare among teenaged Americans.

Adolescent↗
PubMed1990

A factor contained in plasma is required for IGF binding protein-1 to potentiate the effect of IGF-I on smooth muscle cell DNA synthesis.

One of the forms of the insulin-like growth factor (IGF) binding proteins present in human amniotic fluid has been shown to potentiate the growth-promoting effect of IGF-I markedly. This study was undertaken to determine the cellular and hormonal factors that modulate this potentiation and to determine whether this protein would potentiate the effects of other mitogens. Although the combination of the IGFBP-1 (20 ng/ml) and IGF-I (10 ng/ml) induced a five- to sixfold increase in DNA synthesis compared with IGF-I alone, this response required the simultaneous addition of IGF-I with 0.1% platelet-poor plasma (PPP). If PPP was omitted from the incubation medium, no increase above the effect that was obtained with IGF-I alone was noted. Substitution of cerebrospinal fluid (CSF) for PPP permitted a full mitogenic response, although substitution with amniotic fluid resulted in no enhancement. The factor contained in PPP was heat and acid stable. If the binding protein was co-incubated with fibroblast growth factor (FGF), platelet-derived growth factor (PDGF), or epidermal growth factor (EGF), a slight inhibition of the cellular response to each of these factors was detected. Co-incubation of IGF-I with the IGF-binding protein plus these other peptide growth factors resulted in no further enhancement of DNA synthesis above the level observed with IGF-I and the binding protein alone. Likewise, addition of plasma proteins such as transferrin or albumin did not result in a further enhancement of the DNA synthesis response to IGF-I plus binding protein, and these proteins could not substitute for PPP or IGFBP-1. Transient exposure of the cultures (2 hr) to the binding protein plus IGF-I resulted in a submaximal DNA synthesis response, and the binding protein had to be present continuously to achieve a maximal effect. These studies indicate that a factor contained in plasma and CSF is required for a maximal cellular response to IGFBP-1 plus IGF-I, and this factor does not appear to be a well-defined mitogen.

Animals↗
PubMed1990

Tracking the spread of the HIV infection epidemic among young adults in the United States: results of the first four years of screening among civilian applicants for U.S. military service.

Because the period from infection to clinically apparent disease is long, variable, and changing as new therapies are developed and applied, AIDS data are inadequate for tracking current values of critical parameters of HIV infection epidemics: prevalence of infection, rate of acquisition of new infections (incidence rate), and direction and rate of change of infection incidence over time (acceleration). These "vital signs" of infection epidemics can be tracked using serial cross-sectional seroprevalence data, however. From October 1985 through September 1989, more than 2.3 million applicants for U.S. military service were screened for antibody to HIV. The overall seroprevalence was 1.31 per 1,000 (3,014/2,300,675). Seroprevalences were highest near urban centers of the AIDS epidemic and were independently associated with age, race/ethnicity, and gender. Based on age seroprevalence trends, it was crudely estimated that at least one of 2,000 young men and one of 7,000 young women are infected with HIV annually in the U.S. Infection incidence rates, estimated from age and temporal trends, were estimated to be highest among black males (1.40/1,000/year) and lowest among white females (0.03/1,000/year). Poisson regression analysis of seroprevalence trends suggested that infection incidence rates accelerated among black females during the first 3 years of screening. Since selection factors undoubtedly changed over the period, estimates based on these data probably underestimate actual values in the general population, particularly near urban AIDS epicenters. Nonetheless, even crude estimates of these critical values, particularly among adolescents and young adults, are useful to guide policy development, to allocate resources, and to monitor program effects.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Evidence for spread of the human immunodeficiency virus epidemic into low prevalence areas of the United States.

Reports of an increased proportion of AIDS cases occurring in small and medium-sized cities suggest that the HIV epidemic may be spreading into locations that were previously characterized by their low HIV antibody prevalences. Studying the question of the geographic spread of the HIV infection epidemic (rather than the AIDS epidemic) has been difficult largely because most serial seroprevalence data have been gathered from cohorts of high risk individuals (e.g., homosexual/bisexual cohorts) in New York City, San Francisco, and other geographically circumscribed areas. The U.S. military applicant HIV screening data were used in the current report to examine rates and 24 month temporal trends in geographic areas characterized by their HIV endemicities. The data examined concern the seven most populous states and four hyperendemic metropolitan areas located within those states (New York City, Miami, Houston, and San Francisco). In the nonepidemic regions, seroprevalence rates increased among black and white applicants. In the four epidemic urban areas, only young black applicants had higher HIV seroprevalence rates during the second 12 month period. Six of the seven nonepidemic regions had positive HIV seroprevalence trends, and these trends were significant in Florida, California, Texas, Illinois, and Ohio. The increases in these regions were greater for young blacks (30% excess for year 2 vs. year 1) compared to young whites (12% excess for year 2 vs. year 1). These data provide evidence of birth year specific increases in seroprevalence over time occurring in presumed low HIV prevalence areas. These increases cannot be due to, but are observed in spite of, biases associated with increasing self-selection over time.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Prevention of lower extremity stress fractures: a controlled trial of a shock absorbent insole.

A prospective controlled trial was carried out to determine the usefulness of a viscoelastic polymer insole in prevention of stress fractures and stress reactions of the lower extremities. The subjects were 3,025 US Marine recruits who were followed for 12 weeks of training at Parris Island, South Carolina. Polymer and standard mesh insoles were systematically distributed in boots that were issued to members of odd and even numbered platoons. The most important finding was that an elastic polymer insole with good shock absorbency properties did not prevent stress reactions of bone during a 12-week period of vigorous physical training. To control for the confounding effects of running in running shoes, which occurred for about one and one-half hours per week for the first five weeks, we also examined the association of age of shoes and cost of shoes with injury incidence. A slight trend of increasing stress injuries by increasing age of shoes was observed. However, this trend did not account for the similarity of rates in the two insole groups. In addition, we observed a strong trend of decreasing stress injury rate by history of increasing physical activity, as well as a higher stress injury rate in White compared to Black recruits. The results of the trial were not altered after controlling for these factors. This prospective study confirms previous clinical reports of the association of stress fractures with physical activity history. The clinical application of a shock absorbing insole as a preventive for lower extremity stress reactions is not supported in these uniformly trained recruits. The findings are relevant to civilian populations.

Adolescent↗
PubMed1987

Human immunodeficiency virus infections among civilian applicants for United States military service, October 1985 to March 1986. Demographic factors associated with seropositivity.

During the six months from October 1985 through March 1986, blood samples from 306,061 civilian applicants for military service from the United States were tested for antibody to the human immunodeficiency virus (HIV). Four hundred sixty subjects were positive for the antibody as determined by Western (immune) blot reactivity. The mean prevalence of HIV infection in this population of teenagers and young adults was thus 1.50 per 1000. According to multivariate analysis, the following demographic factors were found to be significant independent predictors of a positive HIV-antibody test: age (adjusted odds ratio = 1.10 per year), black race (adjusted odds ratio = 2.04), male sex (adjusted odds ratio = 1.84), residence in a densely populated county (adjusted odds ratio = 1.05 per 1000 per square mile), and residence in a metropolitan area with a high incidence of the acquired immunodeficiency syndrome (adjusted odds ratio = 1.53). Antibody-positive applicants were identified in 43 of the 50 states. Counties with high prevalence rates for HIV (greater than 5 per 1000) were located in New York State (four counties), New Jersey (three counties), California (two counties), Maryland (two counties), and Texas, Colorado, and Washington, D.C.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Occupational and geographic risk factors for hepatitis B among US Army enlisted personnel during 1980.

Hepatitis B hospitalization rates for US Army enlisted personnel were determined by occupation and geographic area for 1980. The only group in the US Army currently recommended to receive hepatitis B vaccine is medical personnel regularly exposed to blood. Other groups of Army personnel, specifically those working in areas of high hepatitis B endemicity, have been thought to be at higher risk. Therefore, this work was undertaken to document hospitalization rates for all personnel using occupational blood exposure criteria as well as geographic area of assignment as risk factors for hepatitis B. The hospitalization rates underestimate true rates of hepatitis B incidence by a wide margin, and therefore were not used to calculate specific costs and specific benefits for a new vaccination strategy. In spite of this limitation, these data were useful for calculating relative risk, attributable risk, and amount of vaccine preventable disease. The risk of hospitalization for blood-exposed employees was consistently higher than that for non-blood-exposed personnel. The magnitude of the relative risk for blood exposure may be as high as 3.8 times or as low as 1.2 times, depending on which occupational comparison group is used. The relative risk of hospitalization in South Korea vs. the United States was 3.1 (p less than 0.0001), that for Europe vs. the United States, 2.1 (p less than 0.0001). Of all occupational and geographic risk comparisons, assignment to South Korea carried the highest attributable risk: 225 per 100,000. The amount of vaccine preventable disease in personnel assigned to South Korea was similar to that in occupationally blood-exposed employees (5.5 vs. 5.2 hospitalized cases per 1,000 vaccinees) after prorating exposure to risk based on average number of days of exposure to risk over three years. These data support the argument that geographic factors are as important as occupational blood exposure in defining risk of hepatitis B hospitalization among the US Army enlisted personnel.

Blood↗
PubMed1984

Prevalence of diabetes in Mexican Americans. Relationship to percent of gene pool derived from native American sources.

We have estimated the prevalence of non-insulin-dependent diabetes mellitus (NIDDM) in Mexican Americans and Anglos in three San Antonio neighborhoods. The age-adjusted NIDDM rates (both sexes pooled) for Mexican Americans were 14.5%, 10%, and 5% for residents of a low-income barrio, a middle-income transitional neighborhood, and a high-income suburb, respectively. In Mexican American women, though not in men, obesity also declined from barrio to suburbs. We have previously shown, however, that, although obesity is an important cause of NIDDM in Mexican Americans, there is a two- to fourfold excess in the rate of NIDDM in this ethnic group over and above that which can be attributed to obesity. We therefore speculated that genetic factors might also contribute to excess NIDDM in this ethnic group. The percent native American admixture of Mexican Americans as estimated from skin color measurements was 46% in the barrio, 27% in the transitional neighborhood, and 18% in the suburbs. The NIDDM rates in Mexican Americans thus paralleled the proportion of native American genes. Furthermore, the San Antonio Mexican American rates were intermediate between the NIDDM rates of "full-blooded" Pima Indians (49.9%), who presumably have close to 100% native American genes, and the San Antonio Anglo population (3.0%) and the predominantly Anglo HANES II population (3.1%), both of which presumably have few if any native American genes. The association of genetic admixture with NIDDM rates suggests that much of the epidemic of NIDDM in Mexican Americans is confined to that part of the population with a substantial native American heritage.

Adult↗