Prevalence and impact of risk factors for lower body difficulty among Mexican Americans, African Americans, and whites

BACKGROUND: The purpose of the study was to estimate the prevalence of sociodemographic, health behavior, chronic disease, and impairment factors and their impact on difficulty in lower body function among two age-cohorts (51-61 and 71-81 years) of Mexican Americans, African Americans, and Whites. METHODS: Reports from 8,727 and 4,510 self-respondents of the 1992 baseline Health and Retirement Survey and the 1993 baseline Assets and Health Dynamics Study, respectively, were used to estimate prevalence. Multiple linear regression of the 4-item lower body difficulty scale (alpha = .80) was used to estimate the direct effects of the risk factors within the age-cohort and ethnicity groups. RESULTS: Overall, the risk factors are more prevalent among both minority groups and the older age-cohort. Lower body deficits are particularly high among Mexican Americans and the younger age-cohort of African Americans. The impact of risk factors does not vary much by ethnicity or age-cohort. Female gender, pain, arthritis, and heart and lung disease are the major risk factors, and they account for about one-third of the variance in lower body difficulty for each group. CONCLUSIONS: Efforts to prevent or reduce lower body difficulty should pay particular attention to pain, arthritis, and heart and lung disease. The central role of sociodemographic and behavioral factors in chronic disease argues for their continued inclusion in disability modeling and prevention.     

Alternaria as a major allergen for asthma in children raised in a desert environment

The relationships of asthma and allergic rhinitis with individual immediate skin test responses were examined for preferential associations and for changes with age in children raised in a semiarid environment. Prevalence of physician-diagnosed asthma was 9.8% at age 6 (n = 948) and 15.5% at age 11 (n = 895). Immediate skin test responses to Bermuda grass were the most prevalent among children with allergic rhinitis and control subjects, whereas responses to the mold, Altenaria alternata, were the most prevalent among asthmatics. Skin test responses for crude house dust, Dermatophagoides farinae, and cat had low prevalences in all groups. By logistic regression, Alternaria was the only allergen independently associated with increased risk for asthma at both ages 6 and 11. Allergic rhinitis showed independent association with sensitization to Bermuda grass and mulberry tree pollen at age 11 but did not show an independent relation to any single allergen at age 6. Logistic regression further revealed that persistent asthma (diagnosed before age 6) was independently associated with Alternaria skin tests at both ages 6 and 11, whereas new asthma (diagnosed after age 6) was associated with Alternaria skin tests at age 6 but not at age 11. We conclude that Alternaria is the major allergen associated with the development of asthma in children raised in a semiarid environment and that skin test responses at age 6 are more closely linked to asthma than those at age 11.     

The response of lung epithelium to well characterised fine particles

Diesel particles form a large component of the fine particle fraction (PM10) in urban air in the UK. During pollution episodes small increases in PM10 have been linked to detrimental health effects. The comparative toxicological effects of diesel exhaust and other well-characterised particles (carbon black, amorphous and crystalline silica) on rat respiratory epithelium were investigated in the present study. The effects of small masses of particles (1 mg) delivered by intratracheal instillation were monitored by changes in components of lavage fluid. Respirable, crystalline quartz, produced significant increases in lung permeability, persistent surface inflammation, progressive increases in pulmonary surfactant and activities of epithelial marker enzymes up to 12 weeks after primary exposure. Ultrafine amorphous silica did not induce progressive effects but it promoted initial epithelial damage with permeability changes and these regressed with time after exposure. By contrast, ultrafine/fine carbon black had little, if any, effect on lung permeability, epithelial markers or inflammation, despite being given at a dose which readily translocated the epithelium and which has been reported to induce inflammation. Similarly, diesel exhaust particles produced only minimal changes in lavage components, although they were smaller individual particles and differed in surface chemistry from carbon black. It is concluded that diesel exhaust particles are less damaging to respiratory epithelium than silicon dioxide and that the surface chemistry of a particle is more important than ultrafine size in explaining its biological reactivity.     

Treatment with protease inhibitors associated with peripheral insulin resistance and impaired oral glucose tolerance in HIV-1-infected patients

BACKGROUND: The use of protease inhibitors in the treatment of HIV-1 infection is associated with the new onset of diabetes mellitus, hyperlipidaemia and lipodystrophy. It is unclear whether these findings are coincidental or whether they reflect a causative effect of protease inhibitors. OBJECTIVE: To evaluate the effect of treatment with protease inhibitors on insulin sensitivity, oral glucose tolerance and serum lipids in HIV-infected patients in order to determine whether treatment with protease inhibitors can cause peripheral insulin resistance. DESIGN: Cross-sectional controlled study in HIV-infected patients treated with protease inhibitors to assess insulin sensitivity, oral glucose tolerance and changes in serum lipids. METHODS: Sixty-seven patients treated with protease inhibitors, 13 therapy-naive patients and 18 HIV-negative control subjects were tested for insulin sensitivity (intravenous insulin tolerance test). In a subgroup of 24 treated patients, oral glucose tolerance was determined. Serum lipids prior to and under treatment with protease inhibitors were compared. RESULTS: Patients on protease inhibitors had a significantly decreased insulin sensitivity when compared with therapy-naive patients (median, 75 and 156 micromol/l/min, respectively; P < 0.001). All treated patients with impaired (n=4) or diabetic (n=9) oral glucose tolerance, and four out of 11 patients with normal glucose tolerance showed peripheral insulin resistance; all therapy-naive patients had normal insulin sensitivity. Treatment with protease inhibitors led to a significant increase in total triglycerides and cholesterol in the 67 treated patients (median increase, 113 and 37 mg/ml, respectively). CONCLUSION: Treatment with protease inhibitors is associated with peripheral insulin resistance, leading to impaired or diabetic oral glucose tolerance in some of the patients, and with hyperlipidaemia. Overall, there is a large variation in the severity and clinical presentation of protease inhibitor-associated metabolic side-effects.     

Food flavor and nutritional characteristics alter dynamics of food preference in lambs

We addressed two questions involving food preference. First, we determined how a food's flavor and nutritional characteristics affected preference. In three trials, we offered lambs isonitrogenous foods differing in energy (trial 1, 90% TDN; trial 2, 100% TDN; trial 3, 110% TDN); each food was offered in apple and maple flavors. We hypothesized that preference for apple- or maple-flavored food would decrease with increasing duration of exposure (1, 2, or 4 d), and we speculated that the change in preference would intensify when food contained inadequate or excessive levels of energy. After eating food in one flavor, lambs preferred the alternative flavor, even after only a 1-d exposure, and preference for the alternative flavor was greater when the food had inadequate or excessive energy (P < .05). The second experiment determined whether eating a food with rapidly or slowly digestible sources of energy in the morning affected lambs' food preferences in the evening. We speculated that lambs fed rapidly digestible food in the morning may prefer a slowly digestible food in the afternoon because slowly digestible food better maintains nutrient status throughout the night or because preference for the rapidly digestible food decreases after exposure in the morning. We offered lambs isonitrogenous and isocaloric foods, that differed in rates of digestion, in apple and maple flavors. Lambs fed rapidly digestible food in the morning preferred slowly digestible food in the alternative flavor in the evening. However, lambs fed slowly digestible food in either flavor in the morning preferred slowly digestible food in both flavors in the evening (P < .05). These results show that lambs' preferences change as a result of food ingestion, and the degree of change in preference depends on the nutritional characteristics of the food. These findings further suggest food intake might be increased by providing a variety of foods to livestock on rangelands, pastures, or in confinement.     

p53 is essential for developmental neuron death as regulated by the TrkA and p75 neurotrophin receptors

Naturally occurring sympathetic neuron death is the result of two apoptotic signaling events: one normally suppressed by NGF/TrkA survival signals, and a second activated by the p75 neurotrophin receptor. Here we demonstrate that the p53 tumor suppressor protein, likely as induced by the MEKK-JNK pathway, is an essential component of both of these apoptotic signaling cascades. In cultured neonatal sympathetic neurons, p53 protein levels are elevated in response to both NGF withdrawal and p75NTR activation. NGF withdrawal also results in elevation of a known p53 target, the apoptotic protein Bax. Functional ablation of p53 using the adenovirus E1B55K protein inhibits neuronal apoptosis as induced by either NGF withdrawal or p75 activation. Direct stimulation of the MEKK-JNK pathway using activated MEKK1 has similar effects; p53 and Bax are increased and the subsequent neuronal apoptosis can be rescued by E1B55K. Expression of p53 in sympathetic neurons indicates that p53 functions downstream of JNK and upstream of Bax. Finally, when p53 levels are reduced or absent in p53+/- or p53-/- mice, naturally occurring sympathetic neuron death is inhibited. Thus, p53 is an essential common component of two receptor-mediated signal transduction cascades that converge on the MEKK-JNK pathway to regulate the developmental death of sympathetic neurons.     

Altered efficacy and selectivity of tyrosine kinase inhibitors of the activated states of protein tyrosine kinases

Listeria monocytogenes is a pathogenic bacterium which has been implicated in several foodborne illnesses. This microorganism grows into biofilms attached to the surfaces in food-processing plants, increasing its resistance to antimicrobial agents. The present work was realized to investigate the attachment of L. monocytogenes isolates to glass surfaces and to find a decontamination procedure to remove these bacteria in biofilms. Three-day biofilms were prepared by growing L. monocytogenes isolates from food plant environments on glass surfaces. Sixteen decontamination treatments at different pHs, temperatures, and times of exposure were tested against L. monocytogenes biofilms. The most efficient treatments were those applied at 63 degrees C. Combinations of decontamination treatments applied at 55 degrees C for 30 min provided different results according to the other factors used. In general, L. monocytogenes biofilms were found to be not very susceptible to high osmolarity (10.5% NaCl), and the interaction of sodium chloride and acid did not seem to have important effects in inactivating these bacteria (from a 1.3-to a 1.9-log-CFU/cm2 reduction). The combination of NaOH (pH 10.5; 100 mM) and acetic acid (pH 5.4; 76.7 mM) applied sequentially at 55 degrees C for even 5 min was shown to be the most effective treatment to remove L. monocytogenes from biofilms (at least a 4.5-to 5.0-log-CFU/cm2 decline).