SEARCH · Search PubMed
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
A case study of the modelling effects of the news media in reporting an unusual act of violence is presented. Using the naturalistic unobtrusive methodology, the double assassination attempts on President Gerald Ford in September 1975 resulted in an increase in the number of assassination threats for several months threafter. The implications were discussed.
Fluorescence scanning confocal microscopy was used in parallel with batch uptake and breakthrough measurements of transport rates to study the effect of ionic strength on the uptake of lysozyme into SP Sepharose FF. In all cases the adsorption isotherms were near-rectangular. As described previously, the intraparticle profiles changed from slow-moving self-sharpening fronts at low salt concentration, to fast-moving diffuse profiles at high salt concentration, and batch uptake rates correspondingly increased with increasing salt concentration. Shrinking core and homogeneous diffusion frameworks were used successfully to obtain effective diffusivities for the low salt and high salt conditions, respectively. The prediction of column breakthrough was generally good using these frameworks, except for low-salt uptake results. In those cases, the compressibility of the stationary phase coupled with the shrinking core behavior appears to reduce the mass transfer rates at particle-particle contacts, leading to shallower breakthrough curves. In contrast, the fast uptake rates at high ionic strength appear to reduce the importance of mass transfer limitations at the particle contacts, but the confocal results do show a flow rate dependence on the uptake profiles, suggesting that external mass transfer becomes more limiting at high ionic strength. These results show that the complexity of behavior observable at the microscopic scale is directly manifested at the column scale and provides a phenomenological basis to interpret and predict column breakthrough. In addition, the results provide heuristics for the optimization of chromatographic conditions.
OBJECTIVES: This study examined the role of behavioral and material factors in explaining educational differences in all-cause mortality, taking into account the overlap between both types of factors. METHODS: Prospective data were used on 15,451 participants in a Dutch longitudinal study. Relative hazards of all-cause mortality by educational level were calculated before and after adjustment for behavioral factors (alcohol intake, smoking, body mass index, physical activity, dietary habits) and material factors (financial problems, neighborhood conditions, housing conditions, crowding, employment status, a proxy of income). RESULTS: Mortality was higher in lower educational groups. Four behavioral factors (alcohol, smoking, body mass index, physical activity) and 3 material factors (financial problems, employment status, income proxy) explained part of the educational differences in mortality. With the overlap between both types of factors accounted for, material factors were more important than behavioral factors in explaining mortality differences by educational level. CONCLUSIONS: The association between educational level and mortality can be largely explained by material factors. Thus, improving the material situation of people might substantially reduce educational differences in mortality.
The neuroendocrine cerebral caudodorsal cells of Lymnaea stagnalis initiate and coordinate ovulation and egg mass production and associated behaviors through the release of a complex set of peptides that are derived from the caudodorsal cell hormone-I (CDCH-I) precursor. We have previously characterized the CDCH-I peptide. In the present study, we isolated and amino acid sequenced by conventional peptide chemistry five additional peptides, epsilon-peptide, calfluxin, alpha-caudodorsal cell peptide, delta-peptide, and carboxyl-terminally located peptide, from the cerebral commissure, the neurohemal area of the caudodorsal cells. Fingerprinting by matrix-assisted laser desorption mass spectrometry of peptides in the commissure demonstrated the presence of all sequenced peptides and, in addition, could identify two other peptides derived from pro-CDCH-1, the beta 1- and beta 3-peptides. These findings together with previous immunocytochemical studies enabled us to define cleavage sites and major processing events of pro-CDCH-1. Pro-CDCH-1 is initially cleaved in the Golgi apparatus into carboxyl- and amino-terminal parts, each of which is sorted into distinct vesicle classes that traffic to different intracellular sites. As a result, in the commissure, peptides derived from the carboxyl-terminal part, including CDCH-1, are present at a many-fold higher concentration than those derived from the amino-terminal part.
A valid method using liquid chromatography-diode array detection-electrospray ionization (ESI) ion trap mass spectrometry was established for the study of the absorbed and metabolic components of a Chinese medicine 'Shuangdan' granule in rat plasma after oral administration. The plasma samples were acidified with 1M hydrochloric acid and extracted with ethyl acetate (EtOAc) of two-fold volume for three times. The chromatographic separation was carried out on a Zorbax SB-C18 column with a linear gradient whereas 0.1% acetic acid/water/acetonitrile was used as mobile phase. Mass spectra were acquired in both negative and positive modes. More than 20 components including 16 components from 'Shuangdan' granule and 5 metabolites were simultaneously identified by comparing their mass spectra and retention behavior with reference compounds or literature data. The results proved that the established method could be used to identify the structure of active components responsible for the pharmacological effects of 'Shuangdan' granule.
Viscosities of aqueous solutions of five polyethylene oxide (PEO) samples with molar masses from 1.5 x 10(5) to 1.0 x 10(6) were carefully measured in a polytetrafluoroethylene (PTFE) capillary Ubbelohde viscometer in the concentration range from dilute down to extremely dilute concentration regions and compared with those of the same sample obtained from a glass capillary viscometer. At the same time, viscosities of aqueous solutions of three PEG samples in glass and paraffin-coated capillary viscosity were measured. The wall effects occurred in viscosity measurements for PEO and PEG aqueous solutions in different capillary viscometers were theoretically analyzed and discussed. It was found that different interfacial behaviors occurred in both hydrophobic and hydrophilic capillary viscometers respectively and the interfacial behaviors also exhibit molar mass dependence.
Trachoma, an ocular infection caused by Chlamydia trachomatis, is the second leading cause of blindness worldwide. The blinding sequelae, which occur in middle age, are felt to be the result of numerous or lengthy episodes of severe inflammatory trachoma in childhood. Risk factors for constant, severe trachoma were identified in a group of children enrolled in a longitudinal study in Kongwa, Tanzania, where villages were randomized in a clinical trial of mass treatment and a behavior modification campaign. In 1989, each of 1,417 randomly selected children had photographs taken of an upper eyelid for determination of their trachoma status. The photographs were graded by a reader who was masked as to the village and date of each photograph. Risk factor data on the family's socioeconomic status, distance to water, and hygiene practices were obtained at baseline. Follow-up examinations occurred 2, 6, and 12 months from baseline. Data from all four time points were available for 82% of the children enrolled. Overall, 10% of the children had constant, severe trachoma, defined as severe trachoma at three or four examinations. The odds ratio for severe trachoma was 1.9 for female children (95% confidence interval 1.3-2.7). Familial cattle ownership and having one or more siblings with trachoma at baseline were also significantly related to the odds of having severe trachoma. Children with a sustainably clean face had lower odds (odds ratio = 0.4, 95% confidence interval 0.3-0.7). A subgroup of 10% of children in these hyperendemic communities always seemed to have severe trachoma, despite enrollment in a mass treatment campaign. Improved face-washing plus antibiotic treatment may decrease the likelihood that these children will be at risk for blinding complications in adulthood.
The crossover behavior of 50 000 molar mass poly(ethylene oxide)/methanol solutions from dilute solution to the melt/gel was examined. At first this behavior was investigated without LiClO(4) and then reexamined with LiClO(4). To better understand this behavior, the dependencies of dynamic light scattering (specifically, photon correlation spectroscopy) measurement results on polymer concentration, on the scattering wave vector and on temperature, and the dependence of static light scattering results on the scattering wave vector were studied. This study produced interesting and important results about network structure and behavior in poly(ethylene oxide) solutions and melts generally and about the effects of LiClO(4) on this structure and behavior more particularly.
OBJECTIVE: The effect of APOE on dementia may be mediated through dyslipidemia and atherogenesis through its effect on cholesterol metabolism. The authors investigated this possibility among aged survivors from the UK Medical Research Council Trial of the Treatment of Hypertension in Older Adults. DESIGN: A total of 370 of 657 survivors from an initial cohort of 1,088 recruited into the trial between 1983 and 1985 were traced in 1994 and agreed to be screened for dementia. Blood samples were analyzed for APOE genotype and serum fibrinogen. Cholesterol level, smoking behavior, blood pressure, body mass index, and EKG recordings had been measured at recruitment 10 to 12 years earlier. Odds ratios (ORs) for the association between APOE epsilon4/* and both AD and dementia were estimated and adjusted incrementally for the effect of age and premorbid intelligence, cholesterol, other risk factors for vascular disease, and EKG evidence of cardiovascular disease. RESULTS: The authors diagnosed 24 cases of National Institute of Neurological and Communicative Disorders and Stroke AD from 41 cases of dementia. The crude OR for the association between APOE epsilon4/* and AD was 3.40 (95% CI 1.30 to 8.91). APOE genotype was associated with serum cholesterol level, and there was a nonsignificant trend for an association with smoking behavior. After adjusting for these and all other vascular risk factors and vascular disease variables listed earlier, the OR for the association between APOE epsilon4/* and AD increased to 4.81 (1.60 to 14.4). CONCLUSION: Presence of APOE epsilon4/* seems to increase the risk for dementia and AD independently of its effect on dyslipidemia and atherogenesis.
BACKGROUND: Undernutrition in nursing home residents is a significant and possibly modifiable public health problem. We evaluated the hypothesis that some potentially modifiable factors are associated with resident undernutrition. METHODS: This study is a cross-sectional, secondary data analysis of 6,832 community nursing home residents sampled from 202 nursing homes in 7 states. Data were from the Minimum Data Set (MDS), and HCFA-mandated resident assessment instrument used in U.S. community nursing homes. Two dependent variables represented undernutrition: (a) low body mass index (BMI), defined as the lowest quartile BMI of the sample (19.42 kg/m2 and below); and (b) weight loss, an MDS measure defined as 5% decrease in weight in 30 days, or a 10% decrease in 180 days (9.9% of the sample). Independent variables included resident demographics, eating-related variables, variables measuring functional, cognitive, and affective statuses, and medical conditions. Separate logistic regression models were estimated for low BMI and weight loss to test multivariate associations. RESULTS: Poor oral intake, eating dependency, decubiti, and chewing problems increase the likelihood of both low BMI and weight loss. Female gender, age 85 or older, bedfast, and hip fracture increase the odds of low BMI only; depressed behaviors and two or more chronic diseases increase the odds of weight loss only. CONCLUSION: Undernutrition in nursing home residents is a multifactorial syndrome. Improved oral feeding methods and treatment of depression are potentially important ways to counteract undernutrition in nursing home residents by targeting reversible features.
The conformational properties of high and low molecular weight galacturonides were investigated in relation to the ability of oligomers with degree of polymerization >10 to act as elicitors of plant defense mechanisms. Oligomers from polygalacturonate were obtained by means of enzymatic hydrolysis. Two fractions exhibiting high and low average degrees of polymerization were isolated by solvent fractionation and characterized by means of electrospray mass spectrometry. The conformational behaviors of the two fractions were investigated in the presence of different divalent cations using circular dichroism. Calcium, copper, and zinc ions were able to induce a conformational transition in both fractions. When in the presence of the high molecular weight fraction, copper and zinc ions were much more effective than calcium ions, whereas the efficiency was much reduced with low molecular weight oligomers.
Food availability is an important factor in the life histories of organisms because it is often limiting and thus can affect growth, mass change, reproduction, and behaviors such as thermoregulation, locomotion, and mating. Experimental studies in natural settings allow researchers to examine the effects of food on these parameters while animals are free to behave naturally. The wide variation among organisms in energy demands and among environmental food resources suggest that responses to changes in food availability may vary among organisms. Since most supplemental feeding field experiments have been conducted on species with high energy demands, we conducted a supplemental feeding study on free-ranging, female Western diamond-backed rattlesnakes (Crotalus atrox), a species with low energy demands and infrequent reproductive investment. Snakes were offered thawed rodents 1-4 times per week. Over two active seasons, we collected data on surface activity, home range size, growth, mass change, and reproduction of supplementally fed and control snakes. Fed and control snakes did not differ in surface activity levels (proportion of time encountered above versus below ground) or home range size. Fed snakes grew and gained mass faster, and had a dramatically higher occurrence of reproduction than control snakes. Also, fed snakes were in better body condition following reproduction than snakes that were not fed. However, litter characteristics such as offspring number and size were not increased by feeding, suggesting that these characteristics may be fixed. These data experimentally demonstrate that food availability can directly impact some life history traits (i.e., growth and reproduction for C. atrox), but not others (i.e., surface activity and home range size for C. atrox). The relationship between food availability and life history traits is affected in a complex way by ecological traits and physiological constraints, and thus interspecific variation in this relationship is likely to be high.
Obesity is an extremely prevalent condition that is associated with a range of deleterious health effects. While traditionally considered a disorder primarily of energy intake, accumulating evidence underscores the importance of energy expenditure in the development and treatment of obesity. As the most variable component of energy expenditure, physical activity can influence the development of obesity as well as success in achieving both initial and long term weight loss. Among the types of exercise-related physiological and behavioural factors most likely to be involved in the development of obesity are reductions in the amount of physical activity actually performed, differences in the effect of physical activity on diet-induced thermogenesis, and modeling of deleterious dietary and exercise patterns on the part of the family and other facets of the environment. In contrast, there is relatively little evidence supporting the common belief that obese individuals have a significantly greater energy intake than nonobese individuals. With respect to weight reduction in the already obese, while increased physical activity levels often augment caloric restriction programmes in aiding initial weight loss, evidence suggests that physical activity may be particularly important in helping to sustain initial losses through increased total energy output, preservation of lean body mass, and changes in substrate utilisation. The psychological benefits received from regular participation in a physical activity programme may serve as an additional impetus for engaging in such activities over the long run. Developing programmes to aid in long term adherence to physical activity regimens remains the most critical challenge. Recent results suggest the utility of regular, brief contacts in aiding sustained physical activity participation in individuals attempting to control their weight.
One diastereomer of trans-zearalenol [2,4-dihydroxy-6-(6,10-dihydroxy-trans-1-undecenyl)-benzoic acid-mu-lactone] was isolated from cultures of Fusarium roseum 'Gibbosum.' This strongly estrogenic metabolite was identified by analysis of its mass spectrum and its behavior in thin-layer, high-pressure liquid and gas-liquid chromatographic systems. The concentration of zearalenol in cultures was 563 mu g/g, or 7% of the 8,000-mu g/g zearalenone content, while the two diastereomers of 8'-hydroxyzearalenone each occurred at 3% of the zearalenone level. Of the two possible diastereomers of zearalenol, the one occurring in cultures was identical to the low-melting-point (171 degrees C) isomer (alpha) obtained by synthesis. In the rat uterus bioassay, the alpha zearalenol isomer was three times more estrogenic than zearalenone while the beta isomer was equal in activity in zearalenone. The two diastereomers of zearalenol can be distinguished from each other by the intensity of the m/e+ 302 fragment of the mass spectrum of the pure underivatized compound.
To study changes in survival, in biological activities and behavior of planorbids submitted to increased hydrostatic pressure, we developed a technique using two transparent chambers and a hydraulic piston. The apparatus permitted renewal of the liquid medium without substantial variations in pressure, thus eliminating excretion products and maintaining the desired O2 level and thereby permitting us to evaluate the effects of pressure independently of the occurrence of anoxia. Pressure was maintained without any contact of the liquid medium with compressed air, a situation which reproduced with relative fidelity what occurs in nature and assured the presence of the same amounts of gases in the two observation chambers (Control and Experimental). Biomphalaria glabrata was found to be able to survive at least 48 hours when submitted to 49.02 x 10(4) Pa (equivalent to a water depth of 48.8 m), continuing to lay egg masses and showing few behavioral changes when compared with the control group.
Several epidemiologic studies show in a concordant way that the prevalence of the overweight and that of obesity increase in France. Obesity is an important risk factor in public health. The main aim of the National Program of Nutrition and Health is to stop the increasing prevalence of childhood obesity. In this framework, we conducted a prevalence study among 1507 schoolchildren (boys: 51,6%; girls: 48,4%) aged from 11 to 17 years old. A self-questionnaire was used to collect information concerning the weight, height and diet. The findings show that 17,6% of collegians are either over weighted or obese, 7,7% of the girls and 10,0% of the boys are in overweight; 5,5% of the girls and 11,7% of the boys are obese, according to the French charts of body mass index (BMI). This study shows a decreasing frequency of the overweight with the age in both males and females: 28,9% at the 11 years old and 13,2% at the 17 years old. Preventive actions are needed at early stages to try to stop and, if possible, to reverse the present increase of overweight. In this context, the itinerant forum of health promotion carried out in the Hauts-de-Seine department with school doctors can play a determining part.
AIM: To investigate the metabolic profile of roxithromycin in dogs and the effects of oral and intravenous administrations on the metabolism of roxithromycin. METHODS: Liquid chromatography-tandem mass spectrometry (LC-MSn) was used for separation and analysis of roxithromycin and its metabolites in dog bile after an oral dose or intravenous dose of roxithromycin. The metabolites were identified by comparisons of their mass spectra and LC behaviors with the references. RESULTS: Totally 13 metabolites were detected in dog bile, including N-demethylated derivatives, N, N-didemethylated derivatives, O-dealkylether derivatives, decladinose derivatives, and the geometric isomers of parent drug and its metabolites. CONCLUSION: Roxithromycin underwent 4 metabolic pathways in which geometric isomerization and decladinose metabolism were found to be markedly different between the two administration routes.
The arousal hypothesis of the trial-spacing effect suggests that spaced-trial training increases emotional arousal and thus invigorates Pavlovian behavior, relative to massed-trial conditions. Emotional arousal was manipulated by varying reinforcer magnitude during training (either one or five food pellets/trial, across groups). In addition, autoshaping training was administered either in the morning (0900 h) or in the evening (1700 h). Rats were housed in an enclosed colony room and exposed to a regular light:dark cycle (light from 0700 to 1900 h). Available evidence indicates that reinforcer magnitude and time of day are related to arousal levels. As expected, a larger reinforcer magnitude led to a highly significant trial spacing effect. Evening training led to a higher response rate than morning training, but the trial-spacing effect was equally strong whether training was administered in the morning or in the evening. These results provide partial support for the arousal hypothesis and are discussed in the context of research on schedule-induced behavior.