Changes in physical activity patterns in the United States, by sex and cross-sectional age

PURPOSE

To determine sex-specific, age-related changes in physical activity patterns.

METHODS

We examined cross-sectional data from the National Health Interview Survey, using the 1992 Youth Risk Behavior Survey supplement for adolescents and the 1991 Health Promotion/Disease Prevention supplement for adults. Physical activity patterns were modeled after Healthy People 2000 objectives.

RESULTS

Among adolescents, physical activity patterns generally eroded most from ages 15 through 18. The "regular, vigorous activity" and strengthening patterns declined consistently from ages 12 through 21. Young adulthood (18-29 yr) often marked continuing erosion of activity patterns, whereas middle adulthood (30-64 yr) often revealed relatively stable patterns. At retirement age (65 yr), there was a stabilizing, or even an improving, tendency in activity patterns, usually followed by further erosion through the final period of life. Strengthening behavior eroded dramatically with advancing age among adults, especially among men. Among adolescents, differences between female and male respondents were large for regular, vigorous activity (11.3 percentage points greater for male respondents). In comparison with female adolescents and adults, male respondents reported much higher rates of regular, sustained activity (5.5 and 5.9 percentage points, respectively), and strengthening (18.2 and 11.3 percentage points, respectively). Among adults, levels of physical inactivity among women were moderately greater (5.5 percentage points) than for men. Absolute rates of change per year were mostly large to very large (3.0-8.0 percentage points x yr(-1)) during ages 15-18 yr, but, for adults, they were small (<0.5 percentage points x yr(-1)) for 33 of 40 sex, age, and pattern groupings.

CONCLUSION

These data suggest that early and continued intervention will be necessary to offset these declines in physical activity throughout adolescence and adulthood.

Dietary fiber, weight gain, and cardiovascular disease risk factors in young adults

CONTEXT

Dietary composition may affect insulin secretion, and high insulin levels, in turn, may increase the risk for cardiovascular disease (CVD).

OBJECTIVE

To examine the role of fiber consumption and its association with insulin levels, weight gain, and other CVD risk factors compared with other major dietary components.

DESIGN AND SETTING

The Coronary Artery Risk Development in Young Adults (CARDIA) Study, a multicenter population-based cohort study of the change in CVD risk factors over 10 years (1985-1986 to 1995-1996) in Birmingham, Ala; Chicago, III; Minneapolis, Minn; and Oakland, Calif.

PARTICIPANTS

A total of 2909 healthy black and white adults, 18 to 30 years of age at enrollment.

MAIN OUTCOME MEASURES

Body weight, insulin levels, and other CVD risk factors at year 10, adjusted for baseline values.

RESULTS

After adjustment for potential confounding factors, dietary fiber showed linear associations from lowest to highest quintiles of intake with the following: body weight (whites: 174.8-166.7 lb [78.3-75.0 kg], P<.001; blacks: 185.6-177.6 lb [83.5-79.9 kg], P = .001), waist-to-hip ratio (whites: 0.813-0.801, P = .004; blacks: 0.809-0.799, P = .05), fasting insulin adjusted for body mass index (whites: 77.8-72.2 pmol/L [11.2-10.4 microU/mL], P = .007; blacks: 92.4-82.6 pmol/L [13.3-11.9 microU/mL], P = .01) and 2-hour postglucose insulin adjusted for body mass index (whites: 261.1-234.7 pmol/L [37.6-33.8 microU/mL], P = .03; blacks: 370.2-259.7 pmol/L [53.3-37.4 microU/mL], P<.001). Fiber was also associated with blood pressure and levels of triglyceride, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and fibrinogen; these associations were substantially attenuated by adjustment for fasting insulin level. In comparison with fiber, intake of fat, carbohydrate, and protein had inconsistent or weak associations with all CVD risk factors.

CONCLUSIONS

Fiber consumption predicted insulin levels, weight gain, and other CVD risk factors more strongly than did total or saturated fat consumption. High-fiber diets may protect against obesity and CVD by lowering insulin levels.

Physical activity, falls, and fractures among older adults: a review of the epidemiologic evidence

OBJECTIVES

Assess the relationship between physical activity and risk for falls and osteoporotic fractures among older adults.

DESIGN

Review and synthesis of published literature.

MEASUREMENTS

We searched the literature using MEDLINE, Current Contents, and the bibliographies of articles identified. We included randomized controlled trials (RCT) of the effects of physical activity on the incidence of falls and case-control and prospective cohort studies of the association of physical activity with osteoporotic fracture risk. We also summarized mechanisms whereby physical activity may influence risk for falls and fractures.

RESULTS

Observational epidemiologic studies and randomized clinical trials evaluating the effectiveness of physical activity programs to prevent falls have been inconclusive. However, many studies have lacked adequate statistical power, and recent trials suggest that exercise, particularly involving balance and lower extremity strength training, may reduce risk of falling. There is consistent evidence from prospective and case-control studies that physical activity is associated with a 20-40% reduced risk of hip fracture relative to sedentary individuals. The few studies that have examined the association between physical activity and risk of other common osteoporotic fractures, such as vertebral and wrist fractures, have not found physical activity to be protective.

CONCLUSIONS

Epidemiologic studies suggest that higher levels of leisure time physical activity prevent hip fractures and RCTs suggest certain exercise programs may reduce risk of falls. Future research needs to evaluate the types and quantity of physical activity needed for optimal protection from falls and identify which populations will benefit most from exercise.

Dietary fiber and body-weight regulation. Observations and mechanisms

Dietary fiber may be related to body-weight regulation through plausible physiologic mechanisms that have considerable support in the scientific literature. Many short-term studies suggest that high-fiber foods induce greater satiation and satiety. Epidemiologic studies generally [figure: see text] support a role for fiber in body-weight regulation among free-living individuals consuming self-selected diets, although conclusive intervention studies addressing this point are lacking. Thus, there is considerable reason to conclude that fiber-rich diets, containing non-starchy vegetables, fruits, whole grains, legumes, and nuts, may be effective in the prevention and treatment of obesity in children. Such diets may have additional benefits, independent of changes in adiposity, in the prevention of cardiovascular disease and type 2 diabetes.

An atypical subcutaneous infection associated with acquired immune deficiency syndrome

Cases of acquired immune deficiency syndrome (AIDS) continue to be reported at an alarming rate. As the numbers of cases increase, so too does the list of unusual manifestations associated with this syndrome. We report here a patient with AIDS who, during his clinical course, had a previously undescribed, histologically atypical, subcutaneous infection develop. Light microscopic, electron microscopic, and microbiologic data are presented. The cause and pathogenesis of this lesion are discussed.

Genomic and epidemiological monitoring of yellow fever virus transmission potential

The yellow fever virus (YFV) epidemic in Brazil is the largest in decades. The recent discovery of YFV in Brazilian Aedes species mosquitos highlights a need to monitor the risk of reestablishment of urban YFV transmission in the Americas. We use a suite of epidemiological, spatial, and genomic approaches to characterize YFV transmission. We show that the age and sex distribution of human cases is characteristic of sylvatic transmission. Analysis of YFV cases combined with genomes generated locally reveals an early phase of sylvatic YFV transmission and spatial expansion toward previously YFV-free areas, followed by a rise in viral spillover to humans in late 2016. Our results establish a framework for monitoring YFV transmission in real time that will contribute to a global strategy to eliminate future YFV epidemics.

A low-glycemic index diet in the treatment of pediatric obesity

CONTEXT

Conventional dietary approaches for the treatment of obesity have generally yielded disappointing results.

OBJECTIVE

To examine the effects of a low-glycemic index (GI) diet compared with a standard reduced-fat diet in the management of pediatric obesity.

DESIGN

Retrospective cohort study of children attending an outpatient pediatric obesity program from September 1997 to December 1998.

SETTING

Academic medical center.

PARTICIPANTS

One hundred seven obese but otherwise healthy children.

MAIN OUTCOME MEASURES

Changes in body mass index (BMI [calculated as weight in kilograms divided by the square of height in meters]) and body weight from first to last clinic visit.

RESULTS

A total of 64 patients received the low glycemic index diet and 43 received the reduced-fat diet for 4.3 vs 4.2 months' mean duration of follow-up, with 3.3 vs 3.3 mean number of visits, respectively. Body mass index (-1.53 kg/m(2) [95% confidence interval, -1.94 to -1.12] vs -0.06 kg/m(2) [-0.56 to + 0. 44], P<.001) and body weight (-2.03 kg [95% confidence interval -3. 19 to -0.88] vs +1.31 kg [ -0.11 to + 2.72], P<.001) decreased more in the low-GI group compared with the reduced-fat group. In multivariate models, these differences remained significant (P<.01) after adjustment for age, sex, ethnicity, BMI or baseline weight, participation in behavioral modification sessions, and treatment duration. Significantly more patients in the low-GI group experienced a decrease in BMI of at least 3 kg/m(2) (11 kg/m(2) [17. 2%] vs. 1 kg/m(2) [2.3%], P =.03).

CONCLUSIONS

A low-GI diet seems to be a promising alternative to standard dietary treatment for obesity in children. Long-term randomized controlled trials of a low-GI diet in the prevention and treatment of obesity are needed.

Effects of the phytochemicals, curcumin and quercetin, upon azoxymethane-induced colon cancer and 7,12-dimethylbenz[a]anthracene-induced mammary cancer in rats

Curcumin and quercetin were evaluated in rats for their ability to modulate the carcinogenic activity of azoxymethane (AOM) in the colon and 7,12-dimethylbenz[a]anthracene (DMBA) in the mammary gland. In the AOM-induced colon cancer model, male Fischer 344 rats at 8 weeks of age started to receive either curcumin (8 and 16 g/kg) or quercetin (16.8 and 33.6 g/kg) in the diet and 1 week later, were administered AOM (30 mg/kg body wt.) by subcutaneous injection. The animals continued to receive the two agents in the diet until sacrificed 45 weeks later. Curcumin mediated a dose-dependent inhibition of the incidence and multiplicity of adenomas from 47% and 0.58 +/- 0.12 adenomas/rat in the AOM-treated control group to 19% and 0.22 +/- 0.08 and 0.06% and 0.08 +/- 0.06 adenomas/rat for the low and high dose groups, respectively. A low yield of adenocarcinomas (0.06 +/- 0.04 adenocarcinomas/rat) was induced by AOM which was not significantly altered by curcumin. Treatment with quercetin caused a dose-dependent increase in the yield of AOM-induced tumors in the colon from 0.06 +/- 0.04 adenocarcinoma/rat to 0.64 +/- 0.12 and 1.14 +/- 0.17 for the low and high dose groups, respectively. In the DMBA-induced mammary cancer model, curcumin or quercetin was administered at either 10 or 20 g/kg diet, beginning 7 days prior to DMBA and continually throughout the remainder of the experiment. Neither curcumin nor quercetin significantly altered the incidence of animals with tumors or the tumor multiplicity, while the high concentration of both agents significantly increased tumor latency. These results demonstrate different responses to these agents in the two models. While curcumin was highly effective as a chemopreventive agent in the colon model, it was only weakly effective in the mammary model. In contrast, quercetin which was also only weakly effective in the mammary model, caused a dose-dependent enhancement of tumors induced by AOM in the colon model.

The carcinogenicity of trichloroethylene and its metabolites, trichloroacetic acid and dichloroacetic acid, in mouse liver

Trichloroethylene (TCE) has previously been shown to be carcinogenic in mouse liver when administered by daily gavage in corn oil. The metabolism of TCE results, in part, in the formation of trichloroacetic acid (TCA) as a major metabolite and dichloroacetic acid (DCA) as a minor metabolite. These chlorinated acetic acids have not been shown to be genotoxic, although they have been shown to induce peroxisome proliferation. Therefore, we determined the ability they have been shown to induce peroxisome proliferation. Therefore, we determined the ability of TCE, TCA, or DCA to act as tumor promoters in mouse liver. Male B6C3F1 mice were administered intraperitoneally 0, 2.5, or 10 micrograms/g body wt ethylnitrosourea (ENU) on Day 15 of age. At 28 days of age, the mice were placed on drinking water containing either TCE (3 or 40 mg/liter), TCA (2 or 5 g/liter), or DCA (2 or 5 g/liter). All drinking waters were neutralized with NaOH to a final pH of 6.5-7.5. The animals were killed after 61 weeks of exposure to the treated drinking water (65 weeks of age). Both DCA and TCA at a concentration of 5 g/liter were carcinogenic without prior initiation with ENU, resulting in hepatocellular carcinomas in 81 and 32% of the animals, respectively. DCA and TCA also increased the incidence of animals with adenomas and the number of adenomas/animal in those animals that were not initiated with ENU. While 2.5 micrograms/g body wt ENU followed by NaCl in the drinking water resulted in only 5% of the animals with hepatocellular carcinomas, 2.5 micrograms/g body wt ENU followed with 2 or 5 g/liter DCA resulted in a 66 or 78% incidence of carcinoma, respectively, or, followed with 2 or 5 g/liter TCA, resulted in a 48% incidence at either concentration. None of the untreated animals had hepatocellular carcinomas. Therefore our results demonstrate that DCA and TCA are complete hepatocarcinogens in B6C3F1 mice.

Mesenchymal stromal cell-derived extracellular vesicles rescue radiation damage to murine marrow hematopoietic cells

Mesenchymal stromal cells (MSCs) have been shown to reverse radiation damage to marrow stem cells. We have evaluated the capacity of MSC-derived extracellular vesicles (MSC-EVs) to mitigate radiation injury to marrow stem cells at 4 h to 7 days after irradiation. Significant restoration of marrow stem cell engraftment at 4, 24 and 168 h post irradiation by exposure to MSC-EVs was observed at 3 weeks to 9 months after transplant and further confirmed by secondary engraftment. Intravenous injection of MSC-EVs to 500cGy exposed mice led to partial recovery of peripheral blood counts and restoration of the engraftment of marrow. The murine hematopoietic cell line, FDC-P1 exposed to 500cGy, showed reversal of growth inhibition, DNA damage and apoptosis on exposure to murine or human MSC-EVs. Both murine and human MSC-EVs reverse radiation damage to murine marrow cells and stimulate normal murine marrow stem cell/progenitors to proliferate. A preparation with both exosomes and microvesicles was found to be superior to either microvesicles or exosomes alone. Biologic activity was seen in freshly isolated vesicles and in vesicles stored for up to 6 months in 10% dimethyl sulfoxide at -80 °C. These studies indicate that MSC-EVs can reverse radiation damage to bone marrow stem cells.

Use of azoxymethane-induced foci of aberrant crypts in rat colon to identify potential cancer chemopreventive agents

Foci of aberrant and/or hexosaminidase-negative crypts in rat colon are putative precancerous lesions that have been proposed as biomarkers for short-term bioassays for chemical carcinogens and chemopreventive agents. The ability of a substance to reduce the yield of azoxymethane (AOM)-induced foci in the colon of male Fischer 344 rats, was evaluated as a screening assay for chemopreventive agents. Twenty-eight test agents were administered continuously in the diet from the start of the experiments until the animals were killed 35 days later. AOM was s.c. administered either as 15 mg/kg body wt on days 7 and 14 or as 30 mg/kg body wt on day 7 of the experiment. Foci of aberrant crypts were evaluated in whole mounts of methylene blue-stained colons. AOM induced twice as many foci when administered between 8.40 and 11.00 a.m. than between 2.45 and 5.55 p.m. Calcium salts of carbonate, chloride and glucarate decreased the yield of AOM-induced foci while the acidic salts of lactate and phosphate did not inhibit the formation of foci. Dimethyl-fumarate, fumaric acid, genistein, piroxicam, simethicone, sodium suramin and sulindac reduced the yield of AOM-induced foci of aberrant crypts, with genistein being the most potent. Only piroxicam of this group has previously been shown to inhibit colon cancer, while the rest have yet to be evaluated. Ibuprofen did not inhibit the formation of foci, although it has been reported to inhibit AOM-induced colon cancer in rats. Piroxicam and sulindac appeared to reduce preferentially hexosaminidase-negative foci of aberrant crypts, compared with those of apparently normal morphology. The AOM-induced foci of aberrant crypts assay appears suitable for screening chemicals for chemopreventive action.

Intragastric bacterial activity and nitrosation before, during, and after treatment with omeprazole

Ten healthy volunteers were studied before, during, and after treatment with omeprazole 30 mg daily for two weeks. On the 14th night mean nocturnal (2100-0700) intragastric acidity was significantly decreased by 75% (p less than 0.001). At 0700, 22 hours after the last dose of omeprazole, there were significant increases in the bacterial count and the nitrite and N-nitrosamine concentrations in the gastric juice (p less than 0.001). Three days later these changes had resolved. Short term treatment of healthy volunteers with omeprazole is associated with a short lived increase in the gastric bacterial flora, with endogenous production of N-nitroso compounds.

Anaerobic biodegradation of oleic and palmitic acids: Evidence of mass transfer limitations caused by long chain fatty acid accumulation onto the anaerobic sludge

Palmitic acid was the main long chain fatty acids (LCFA) that accumulated onto the anaerobic sludge when oleic acid was fed to an EGSB reactor. The conversion between oleic and palmitic acid was linked to the biological activity. When palmitic acid was fed to an EGSB reactor it represented also the main LCFA that accumulated onto the sludge. The way of palmitic acid accumulation was different in the oleic and in the palmitic acid fed reactors. When oleic acid was fed, the biomass-associated LCFA (83% as palmitic acid) were mainly adsorbed and entrapped in the sludge that became "encapsulated" by an LCFA layer. However, when palmitic acid was fed, the biomass-associated LCFA (the totality as palmitic acid) was mainly precipitated in white spots like precipitates in between the sludge, which remained "non-encapsulated." The two sludges were compared in terms of the specific methanogenic activity (SMA) in the presence of acetate, propionate, butyrate, and H(2)CO(2), before and after the mineralization of similar amounts of biomass-associated LCFA (4.6 and 5.2 g COD-LCFA/g of volatile suspended solids (VSS), for the oleic and palmitic acid fed sludge, respectively). The "non-encapsulated," sludge exhibited a considerable initial methanogenic activity on all the tested substrates, with the single exception of butyrate. However, with the "encapsulated" sludge only methane production from ethanol and H(2)/CO(2) was detected, after a lag phase of about 50 h. After mineralization of the biomass-associated LCFA, both sludges exhibited activities of similar order of magnitude in the presence of the same individual substrates and significantly higher than before. The results evidenced that LCFA accumulation onto the sludge can create a physical barrier and hinder the transfer of substrates and products, inducing a delay on the initial methane production. Whatever the mechanism, metabolic or physical, that is behind this inhibition, it is reversible, being eliminated after the depletion of the biomass-associated LCFA.

"Subversive" substrates for the enzyme trypanothione disulfide reductase: alternative approach to chemotherapy of Chagas disease

The trypanosomatid flavoprotein disulfide reductase, trypanothione reductase, is shown to catalyze one-electron reduction of suitably substituted naphthoquinone and nitrofuran derivatives. A number of such compounds have been chemically synthesized, and a structure-activity relationship has been established; the enzyme is most active with compounds that contain basic functional groups in side-chain residues. The reduced products are readily reoxidized by molecular oxygen and thus undergo classical enzyme-catalyzed redox cycling. In addition to their ability to act as substrates for trypanothione reductase, the compounds are also shown to effectively inhibit enzymatic reduction of the enzyme's physiological substrate, trypanothione disulfide. Under aerobic conditions, trypanothione reductase is not inactivated by these redox-cycling substrates, whereas under anaerobic conditions the nitrofuran compounds cause irreversible inactivation of the enzyme. When tested for biological activity against Trypanosoma cruzi trypomastigotes, many of the test compounds were trypanocidal, and this activity correlated with their relative ability to act as substrates for trypanothione reductase. The activity of the enzyme with these redox-cycling derivatives constitutes a subversion of its normal antioxidant role within the cell. For this reason these compounds may be termed "subversive" substrates for trypanothione reductase.

Mineralization of LCFA associated with anaerobic sludge: Kinetics, enhancement of methanogenic activity, and effect of VFA

Long-chain fatty acids (LCFA) associated with anaerobic sludge by mechanisms of precipitation, adsorption, or entrapment can be biodegraded to methane. The mineralization kinetics of biomass-associated LCFA were established according to an inhibition model based on Haldane's enzymatic inhibition kinetics. A value around 1,000 mg COD-LCFA..g VSS(-1) was obtained for the optimal specific LCFA content that allowed the maximal mineralization rate. For sludge with specific LCFA contents of 2,838 +/- 63 and 4,571 +/- 257 mg COD-LCFA..g VSS(-1), the specific methanogenic activities in the presence of acetate, butyrate, and H(2)/CO(2) were significantly enhanced after the mineralization of the biomass-associated LCFA. For sludge with a specific LCFA content near the optimal value defined by the kinetic model, the effect of adding VFA to the medium was studied during the mineralization of the biomass-associated LCFA. Different patterns were obtained for each individual substrate. Acetate and butyrate were preferentially consumed by the consortium, but in the case of propionate no evidence of a sequential consumption pattern could be withdrawn. It was concluded that LCFA do not exert a bactericidal neither a permanent toxic effect toward the anaerobic consortia. A discussion is addressed to the relative roles of a reversible inhibitory effect and a transport limitation effect imposed by the LCFA surrounding the cells.

Influence of leisure time physical activity and television watching on atherosclerosis risk factors in the NHLBI Family Heart Study

Physical activity favorably influences atherosclerosis risk factors but only a few studies in adults considered the time watching television (TV) as a measure of physical inactivity. We therefore determined in a population-based sample of 1778 subjects from the NHLBI Family Heart Study (FHS) whether leisure time physical activity and TV watching have independent or interactive associations with cardiovascular disease risk factors and carotid artery intima-media wall thickness (IMT). Subjects were free from diabetes mellitus and clinically-ascertained coronary artery disease and did not take lipid-lowering or antihypertensive drugs. Only 0.7 and 1.3% of the variance in leisure time physical activity in women and men, respectively, was explained by the amount of TV watching. Leisure time physical activity had a clearly favorable, and TV watching an unfavorable association with anthropometric measurements (BMI (body mass index), waist girth, waist-hip ratio, subscapular and triceps skinfold thickness). The odds ratio (95% CI) of being overweight was 0.41 (0.28-0.62) in women and 0.69 (0.46-1.04) in men in the highest quartile of leisure time physical activity compared to the lowest quartile. The odds ratio increased for increasing quartiles of TV watching to 2.12 (1.45-3.10) in women and 1.61 (1.07-2.43) in men. Watching TV only 1 h per day in women with a BMI of 30 kg/m2 and doing about 75 min of moderate exercise per week was associated with a BMI 1.8 kg/m2 lower than in women watching TV 3 h per day and doing the same amount of exercise. Those with twice the amount of moderate exercise and watching TV 1 h per day had a BMI 0.45 kg/m2 lower. Furthermore, leisure time physical activity was negatively associated with concentrations of triglycerides and positively with HDL cholesterol in both genders. TV watching was significantly positively associated with triglycerides and slightly negatively with HDL cholesterol in men. The observed associations of leisure time physical activity and TV watching with atherosclerosis risk factors were independent from each other. Finally, we analyzed the relation between leisure time physical activity, TV watching and the degree of IMT of the carotid arteries. Neither of these two measures was significantly associated with IMT. In summary, TV watching, in addition to leisure time physical activity, shows an independent association with obesity-related anthropometric measurements, HDL and triglycerides. Decreasing the amount of TV watching might be effective as a first step in reducing atherosclerosis risk factors, especially overweight.

Fiber from whole grains, but not refined grains, is inversely associated with all-cause mortality in older women: the Iowa women's health study

BACKGROUND

Inconsistencies in epidemiologic findings relating grain fiber to chronic disease may be explained by differentiating nutrient-rich fiber derived from whole grain vs. nutrient-poor fiber derived from refined grain.

OBJECTIVE

Given that phytochemicals are most varied and abundant in the outer layers of grains, we tested the hypothesis that whole grain fiber consumption is associated with a reduced mortality risk in comparison to a similar amount of refined grain fiber.

DESIGN

11,040 postmenopausal women enrolled in the Iowa Women's Health Study, matched on total grain fiber intake, but differing in the proportion of fiber consumed from whole vs. refined grain, were followed from baseline in 1986 through 31 December, 1997, during which time 1,341 deaths occurred in 124,823 observed woman-years.

RESULTS

After multivariate adjustment in proportional hazards regression, women who consumed on average 1.9 g refined grain fiber/2,000 kcal and 4.7 g whole grain fiber/2,000 kcal had a 17% lower mortality rate (RR=0.83, 95% CI=0.73-0.94) than women who consumed predominantly refined grain fiber: 4.5 g/2,000 kcal, but only 1.3 g whole grain fiber/2,000 kcal.

CONCLUSION

Inferences from studies that have reported associations between grain fiber intake and morbidity or mortality may be limited by not differentiating fiber sources. Future studies should distinguish fiber from whole vs. refined grains. Public health policy should differentiate whole grains from refined, and recommend increased consumption of the former.

Physical activity and incident hypertension in black and white adults: the Atherosclerosis Risk in Communities Study

BACKGROUND

The epidemiologic observation that physical activity reduces the risk for hypertension has only been made for white men who self-reported hypertension. This study examined physical activity and clinically determined incident hypertension in black and white men and women of the Atherosclerosis Risk in Communities (ARIC) Study.

METHODS

ARIC is a population-based prospective study with four U.S. clinic centers. The present analyses included 7,459 black and white adults 45-65 years of age. Hypertension (systolic/diastolic blood pressure >/= 140/90 mm Hg) was defined by blood pressure measured by a random-zero device or medication use. Physical activity was assessed with the Baecke questionnaire.

RESULTS

After adjustment for age, baseline blood pressure, ARIC center, education, body mass index, waist-hip ratio, parental history of hypertension, cigarette smoking, alcohol consumption, and diet, white men in the highest quartile of leisure activity (primarily cycling and walking) had a 34% lower odds of developing hypertension over 6 years compared to the least active (OR = 0.66, 95% CI = 0.47-0.94; P for quartile trend = 0.01). Baseline activity was not associated with incident hypertension in white women or blacks.

CONCLUSIONS

Leisure-time physical activity reduces the odds of hypertension in middle-aged white men. Additional studies in women and blacks are needed.

Preclinical efficacy evaluation of potential chemopreventive agents in animal carcinogenesis models: methods and results from the NCI Chemoprevention Drug Development Program

In the NCI, Chemoprevention Branch drug development program, potential chemopreventive agents are evaluated for efficacy against chemical carcinogen-induced tumors in animal models. This paper summarizes the results of 144 agents in 352 tests using various animal efficacy models. Of these results, 146 were positive, representing 85 different agents. The target organs selected for the animals model are representative of high-incidence human cancers. The assays include inhibition of tumors induced by MNU in hamster trachea, DEN in hamster lung, AOM in rat colon (including inhibition of AOM-induced aberrant crypts), MAM in mouse colon, DMBA and MNU in rat mammary glands, DMBA promoted by TPA in mouse skin, and OH-BBN in mouse bladder. The agents tested may be classified into various pharmacological and chemical structural categories that are relevant to their chemopreventive potential. These categories include antiestrogens, antiinflammatories (e.g., NSAIDs), antioxidants, arachidonic acid metabolism inhibitors, GST and GSH enhancers, ODC inhibitors, protein kinase C inhibitors, retinoids and carotenoids, organosulfur compounds, calcium compounds, vitamin D3 and analogs, and phenolic compounds (e.g., flavonoids). The various categories of compounds have different spectra of efficacy in animal models. In hamster lung, GSH-enhancing agents and antioxidants appear to have high potential for inhibiting carcinogenesis. In the colon, NSAIDs and other antiinflammatory agents appear particularly promising. Likewise, NSAIDs are very active in mouse bladder. In rat mammary glands, retinoids and antiestrogens (as would be expected) are efficacious. Several of the chemicals evaluated also appear to be promising chemopreventive agents based on their activity in several of the animal models. Particularly, the ODC inhibitor DFMO was active in the colon, mammary glands, and bladder models, while the dithiolthione, oltipraz, was efficacious in all the models listed above (i.e., lung, colon, mammary glands, skin, and bladder).

Cardiac arrhythmias in critically ill patients: epidemiologic study

The general prevalence of cardiac arrhythmias in 2,820 consecutive patients was 78%, ranging from 44% in multiple trauma patients to 90% in primary cardiovascular patients. Patients without recorded arrhythmias (22%, n = 621) were used as control subjects. No clinical group was free from cardiac arrhythmias. Atrial tachyarrhythmias had the highest prevalence in the population as a whole (28%) and in all clinical groups except multiple trauma. Atrial fibrillation was the most common atrial arrhythmia (52%); ventricular arrhythmias followed. Patients with atrial tachyarrhythmias, nodal rhythm ventricular bradyarrhythmias, and ventricular rapid rhythms had significantly (p less than .01) increased mortality rates (40%, 44%, 77%, and 51%, respectively) when compared with patients without arrhythmias (35%). The relative risk of dying (RRD) of these clinical groups was increased by 1.16, 1.27, 2.20, and 1.47, respectively. Patients with cardiorespiratory precipitating disease and any arrhythmia except atrial bradyarrhythmia had a mortality rate between 32% and 74%, significantly (p less than .05) different from that of patients within the same clinical groups without arrhythmias. The RRD was increased by 1.67 to 3.40. Septic patients with atrial tachyarrhythmia or nodal rhythm and neurologic patients with nodal or ventricular arrhythmias also had significantly (p less than .01 and .05, respectively) increased mortality and were at higher RRD (1.53 to 2.81). Our data suggest that severe illness may be present in some clinical groups of critically ill patients with cardiac arrhythmias.

Functional mapping of the neural circuitry of rat maternal motivation: effects of site-specific transient neural inactivation

The present review focuses on recent studies from our laboratory examining the neural circuitry subserving rat maternal motivation across postpartum. We employed a site-specific neural inactivation method by infusion of bupivacaine to map the maternal motivation circuitry using two complementary behavioural approaches: unconditioned maternal responsiveness and choice of pup- over cocaine-conditioned incentives in a concurrent pup/cocaine choice conditioned place preference task. Our findings revealed that, during the early postpartum period, distinct brain structures, including the medial preoptic area, ventral tegmental area and medial prefrontal cortex infralimbic and anterior cingulate subregions, contribute a pup-specific bias to the motivational circuitry. As the postpartum period progresses and the pups grow older, it is further revealed that maternal responsiveness becomes progressively less dependent on the medial preoptic area and medial prefrontal cortex infralimbic activity, and more distributed in the maternal circuitry, such that additional network components, including the medial prefrontal cortex prelimbic subregion, are recruited with maternal experience, and contribute to the expression of late postpartum maternal behaviour. Collectively, our findings provide strong evidence that the remarkable ability of postpartum females to successfully care for their developing infants is subserved by a distributed neural network that carries out efficient and dynamic processing of complex, constantly changing incoming environmental and pup-related stimuli, ultimately allowing the progression of appropriate expression and waning of maternal responsiveness across the postpartum period.

Dengue virus type 3 in Rio de Janeiro, Brazil

Dengue virus type 3 was isolated for the first time in the country as an indigenous case from a 40 year-old woman presenting signs and symptoms of a classical dengue fever in the municipality of Nova Iguaçu, State of Rio de Janeiro. This serotype has been associated with dengue haemorrhagic epidemics and the information could be used to implement appropriate prevention and control measures. Virological surveillance was essential in order to detected this new serotype.

Periodontal pathogens in atheromatous plaques isolated from patients with chronic periodontitis

BACKGROUND AND OBJECTIVE

It has been suggested that chronic infections may predispose to cardiovascular disease. The relationship between periodontal disease and cardiovascular disease has been a subject of increasing research in recent years. The isolation and identification of periodontal bacteria from atheromatous plaque can contribute to our knowledge of this vascular disease. The aim of this study was to isolate and identify periodontal bacteria from the periodontal pockets of different patients and to compare them with the microorganisms detected in the atheromatous plaques obtained from the same patients.

MATERIAL AND METHODS

Clinical isolates were obtained from 12 patients with periodontal wounds and atheromathous plaques. These samples were cultured in the appropriate bacteriological culture media and incubated in an anaerobic system. Periodontal bacteria were identified using polymerase chain reaction (PCR) assays.

RESULTS

From the 12 patients studied, nine presented different periodontopathic bacterial species. In two, Actinobacillus actinomycetemcomitans was present in the periodontal pockets and the respective atheromatous plaques.

CONCLUSION

The presence of A. actinomycetemcomitans in atheromatous plaques and the periodontal pockets of the same patients could indicate a role for periodontal pathogenic bacteria in the atherosclerosis disease process.

A randomized walking trial in postmenopausal women: effects on physical activity and health 10 years later

BACKGROUND

It is important to determine if permanent lifestyle changes may result from physical activity interventions and whether health may be affected by these changes.

OBJECTIVE

To conduct a 10-year follow-up of physical activity and self-reported health status in participants of a randomized clinical trial of walking intervention.

METHODS

Of the original 229 volunteer postmenopausal women who participated in the original clinical trial, 196 (N = 96 intervention and 100 controls) completed the 10-year follow-up telephone interview. The interview protocol included questions on self-reported walking for exercise and purposes other than exercise, the Paffenbarger sport and exercise index, functional status, and various chronic diseases and conditions.

RESULTS

The median values for both usual walking for exercise and total walking were significantly higher for walkers compared with controls (for both, P = .01), with median differences of 706 and 420 kcal/wk, respectively. After excluding women who reported heart disease during the original trial, 2 women in the walking group (2%) and 11 women in the control group (12%) reported physician-diagnosed heart disease over the last 10 years (P = .07). There were also fewer hospitalizations, surgeries, and falls among women in the walking group, although these differences were not statistically significant (P>.05).

CONCLUSIONS

Although limited by self-report, this study may be the first to demonstrate long-term exercise compliance to a randomized control trial in older women and to suggest that health benefits may have ensued as a result of these increased activity levels.

Influence of external bacterial structures on the efficiency of photodynamic inactivation by a cationic porphyrin

The main targets of photodynamic inactivation (PDI) are the external bacterial structures, cytoplasmic membrane and cell wall. In this work it was evaluated how the external bacterial structures influence the PDI efficiency. To reach this objective 8 bacteria with distinct external structures were selected; 4 Gram-negative bacteria (Escherichia coli, with typical Gram-negative external structures; Aeromonas salmonicida, Aeromonas hydrophila both with an S-layer and Rhodopirellula sp., with a peptidoglycan-less proteinaceous cell wall and with cytoplasm compartmentalization) and 4 Gram-positive bacteria (Staphylococcus aureus, with typical Gram-positive external structures; Truepera radiovictrix, Deinococcus geothermalis and Deinococcus radiodurans, all with thick cell walls that give them Gram-positive stains, but including a second complex multi-layered membrane and structurally analogous to that of Gram-negative bacteria). The studies were performed in the presence of 5,10,15,20-tetrakis(1-methylpyridinium-4-yl)porphyrin tetraiodide (Tetra-Py(+)-Me) at 5.0 μM with white light (40 W m(-2)). The susceptibility of each bacteria to PDI by Tetra-Py(+)-Me was dependent on bacteria external structures. Although all Gram-positive bacteria were inactivated to the detection limit (reduction of ∼8 log) after 60-180 min of irradiation, the inactivation followed distinct patterns. Among the Gram-negative bacteria, E. coli was the only species to be inactivated to the detection limit (∼8 log after 180 min). The efficiency of inactivation of the two species of Aeromonas was similar (reduction of ∼5-6 log after 270 min). Rhodopirellula was less susceptible (reduction of ∼4 log after 270 min). As previously observed, the Gram-positive bacteria are more easily inactivated than Gram-negative strains, and this is even true for T. radiovictrix, D. geothermalis and D. radiodurans, which have a complex multi-layered cell wall. The results support the theory that the outer cell structures are major bacterial targets for PDI. Moreover, the chemical composition of the external structures has a stronger effect on PDI efficiency than complexity and the number of layers of the external coating, and lipids seem to be an important target of PDI.