Undernutrition can affect the invading microorganism.

Undernutrition or malnutrition adversely affects host defenses against many invading microorganisms, thereby increasing the severity of infection. Studies of RNA viruses (e.g., coxsackievirus B and influenzavirus) have shown that selenium or vitamin E deficiency in mice increases disease severity and results in stable genomic changes in the virus that increase virulence. Changes in H3N2 influenzavirus were predominantly in the ordinarily stable M1 matrix protein. Whether this represents selection of already-existing variants or direct effects on viral RNA is unclear. Related questions include whether undernutrition in persons who acquire infection with influenzavirus H5N1 could promote genomic changes during infection that result in greater virulence and higher case-fatality rates, and whether undernutrition could help create the multiple mutations needed to instigate human-to-human transmission. These possibilities emphasize the importance of alleviating world poverty and malnutrition. In addition, these findings suggest that the neglected area of undernutrition affecting invading microorganisms merits intensive investigation in humans and experimental models.

Elevated blood lead concentrations and vitamin D deficiency in winter and summer in young urban children.

BACKGROUND: It is widely recognized that blood lead concentrations are higher in the summer than in winter. Although the effects of some environmental factors such as lead in dust on this phenomenon have been studied, relationships to sunlight-induced vitamin D synthesis have not been adequately investigated. Vitamin D status is influenced by the diet, sunlight exposure, age, skin pigmentation, and other factors, and may modify gastrointestinal lead absorption or release of lead stored in bones into the bloodstream. OBJECTIVE AND METHODS: We collected paired blood samples from 142 young, urban African-American and Hispanic children in the winter and summer to study the seasonal increase in blood lead and its relationships to vitamin D nutrition, age, and race. RESULTS: A winter/summer (W/S) increase in blood lead concentrations of 32.4% was found for children 1-3 years of age. There was a smaller W/S increase of 13.0% in children 4-8 years of age. None of the 51 Hispanic children had an elevated blood lead concentration (> or = 10 microg/dL) during the winter, and only one had an elevated summertime concentration. In contrast, elevated blood lead concentrations were frequent in the 91 African-American children, especially those 1-3 years of age. For the latter, the percentage with elevated blood lead levels increased from 12.2% in winter to 22.5% in summer. A 1.2% W/S increase in serum 25-hydroxy-vitamin D (serum 25-OH-D) concentrations was found for children 1-3 years of age. However, in children 4-8 years of age the W/S increase in serum 25-OH-D was much larger-33.6%. The percentages of children with low (< 16 microg/L) serum 25-OH-D concentrations were 12.0% in winter and 0.7% in summer and were consistently greater in African-American than in Hispanic children. The seasonal increases in blood lead and serum 25-OH-D in children 4-8 years of age were significantly associated. CONCLUSION: The higher summertime serum 25-OH-D concentrations for the 4- to 8-year-old children are likely caused by increased sunlight-induced vitamin D synthesis and may contribute to the seasonal increase in blood lead. Age and race are key factors that affect blood lead and vitamin D nutrition, as well as their interactions, in young urban children.

Baseline behavioral assessment for the new Jersey Health Wellness Promotion Act.

PURPOSE: To determine baseline use rates for health-promoting behaviors of the recently adopted New Jersey Health Wellness Promotion Act and to examine the effects of demographic and socioeconomic factors on the use of preventive services included in the Act. DESIGN: A random telephone survey of 3094 households was conducted using questions from the Behavioral Risk Factor Surveillance System supplemented by questions related to provisions of the Act. SETTING: All New Jersey households. SUBJECTS: State representative adult sample of 1246 subjects. MEASURES: Rates for getting timely screening tests, for obtaining influenza immunizations, and engaging in selected health-promoting behaviors. RESULTS: Rates for receiving recommended screening tests ranged from 0.88 for blood pressure testing to 0.29 for osteoporosis screening. According to bivariate analysis, having insurance was the most consistent determinant associated with receiving preventive services but was associated only with sigmoidoscopy, mammography, and Pap smear testing in the multivariate modeling. Reminders were significantly associated with respective screening tests. Age was positively associated with receiving the majority of tests. Gender ethnicity, education, and income affected receipt sporadically. Half the respondents were overweight and a quarter were current smokers. CONCLUSIONS: Receipt of appropriate screening tests and adoption of health-promoting behaviors fell short of desired goals. Having health insurance increased receipt rates, but was not enough to achieve usage goals. Procedure-specific reminders may improve usage rates.

Extraordinary longevity: individual and societal issues.

The likelihood of substantial increases in average life spans and the potential for profound longevity increases (to 100, 110, or 120 years on average) raises a host of societal issues. These include huge increases in the number of old and very old persons, the likelihood of a massive increase in health expenditures for the population aged 65 and older, the potential for outliving financial resources, challenges to the viability of Social Security and pensions, concerns about quality of life, and possible intergenerational antagonisms. If marked increases occur in average life spans worldwide, several billions could be added to world population at eventual stability, and that could become a sustainability issue. To prepare for what is likely to be our demographic future requires a major shift in thinking about this type of complex issue; we must change from a simple linear to a much broader systems approach. Changes in retirement age, strengthening (but then replacing) the Social Security system, retaining older persons in the labor force, mandating retirement savings during working years, and many other actions must be considered in a debate that should start now about life span increase and the future; if we dawdle, we risk the consequences of being unprepared for the dramatic demographic changes that are likely to occur in the coming decades.

Lead exposure potentiates predatory attack behavior in the cat.

Epidemiologic studies have demonstrated that environmental lead exposure is associated with aggressive behavior in children; however, numerous confounding variables limit the ability of these studies to establish a causal relationship. The study of aggressive behavior using a validated animal model was used to test the hypothesis that there is a causal relationship between lead exposure and aggression in the absence of confounding variables. We studied the effects of lead exposure on a feline model of aggression: predatory (quiet biting) attack of an anesthetized rat. Five cats were stimulated with a precisely controlled electrical current via electrodes inserted into the lateral hypothalamus. The response measure was the predatory attack threshold current (i.e., the current required to elicit an attack response on 50% of the trials). Blocks of trials were administered in which predatory attack threshold currents were measured three times a week for a total of 6-10 weeks, including before, during, and after lead exposure. Lead was incorporated into cat food "treats" at doses of 50-150 mg/kg/day. Two of the five cats received a second period of lead exposure. Blood lead concentrations were measured twice a week and were <1, 21-77, and <20 micro g/dL prior to, during, and after lead exposure, respectively. The predatory attack threshold decreased significantly during initial lead exposure in three of five cats and increased after the cessation of lead exposure in four of the five cats (P<0.01). The predatory attack thresholds and blood lead concentrations for each cat were inversely correlated (r=-0.35 to -0.74). A random-effects mixed model demonstrated a significant (P=0.0019) negative association between threshold current and blood lead concentration. The data of this study demonstrate that lead exposure enhances predatory aggression in the cat and provide experimental support for a causal relationship between lead exposure and aggressive behavior in humans.

Prevención de los cuadros de diarrea mediante irradiación de los alimentos / Prevention of diarrhea through food irradiation

El autor se opone a la exposición de los alimentos a grandes dosis de radiación hasta que las incógnitas acerca del daño cromosómico y la pérdida de nutrientes se resuelvan.

Dendritic cell amplification of HIV type 1-specific CD8+ T cell responses in exposed, seronegative heterosexual women.

In the Heterosexual AIDS Transmission Study (HATS), the frequency of high-risk sexual activity and viral load in the seropositive partner were shown to correlate with HIV-1 transmission. However, these parameters could not account for the status of some exposed, seronegative (ESN) individuals who remained uninfected despite years of exposure. To test the hypothesis that antiviral immune responses are a correlate of nontransmission in this cohort, we developed two sensitive methods for assessing HIV-1-specific humoral and cell-mediated responses. To quantify T cell responses, autologous mature dendritic cells (DCs) were used as antigen-presenting cells to elicit HIV-1-specific IFN-gamma production by ELISPOT. Antibody responses to HIV-1 gp120 were assessed by combination immunoprecipitation-Western blot (IP-WB). Previous studies of this cohort, using limiting dilution analysis, did not reveal HIV-1-specific cytotoxic T lymphocyte activity. However, when autologous DCs were used to present HIV-1 antigens, T cells from three of eight ESN women (38%) responded by producing IFN-gamma. T cells from three of four seropositive partners responded to HIV-1 antigens, whereas five negative controls did not. The use of DCs as antigen-presenting cells increased sensitivity by 2- to 30-fold relative to standard ELISPOT. Using IP-WB, low levels of gp120-reactive antibodies were detected in plasma from 1 of 14 ESN women. These results support the hypothesis that HIV-1-specific T cell responses play a role in immune surveillance in this cohort of North American serodiscordant couples. This report also demonstrates the ability of dendritic cells to reveal T cell responses that might be overlooked by other methods.

Correlates of nontransmission in US women at high risk of human immunodeficiency virus type 1 infection through sexual exposure.

Seventeen women who were persistently uninfected by human immunodeficiency virus type 1 (HIV-1), despite repeated sexual exposure, and 12 of their HIV-positive male partners were studied for antiviral correlates of non-transmission. Thirteen women had > or = 1 immune response in the form of CD8 cell noncytotoxic HIV-1 suppressive activity, proliferative CD4 cell response to HIV antigens, CD8 cell production of macrophage inflammatory protein-1 beta, or ELISPOT assay for HIV-1-specific interferon-gamma secretion. The male HIV-positive partners without AIDS had extremely high CD8 cell counts. All 8 male partners evaluated showed CD8 cell-related cytotoxic HIV suppressive activity. Reduced CD4 cell susceptibility to infection, neutralizing antibody, single-cell cytokine production, and local antibody in the women played no apparent protective role. These observations suggest that the primary protective factor is CD8 cell activity in both the HIV-positive donor and the HIV-negative partner. These findings have substantial implications for vaccine development.