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At least 19 recordsLinked to original sources
PubMedDate not supplied

Influence of glycosaminoglycan content on mass transfer behavior of porcine artery wall. Part 2. Differences in mass transfer rates related to variations in glycosaminoglycan content.

It has been suggested that the glycosaminoglycans (GAG) influence atherogenesis by regulating the permeability of the arterial wall. For this reason, a study has been made of the diffusive transport of Ca2+ and water across the in vitro porcine artery wall, where particular attention was focused on the influence of GAG content and distribution within the wall on the transport properties. The radioisotop-s 45Ca and 3HHO were used to measure the tracer-diffusion flux in a stirred, two chamber diffusion cell. GAG were isolated, fractionated using a cetyl pyridinium chloride-cellulose column procedure, and assayed using a colorimetric carbazole reaction for uronic acid. The biochemical analyses showed that the pulmonary artery contains significantly more hyaluronic acid and dermatan sulfate than found in two locations in the thoracic aorta. In addition, a significant regression was found for the diffusion coefficient of 45Ca2+ (99% level) and 3HHO (95% level) versus specific GAG fractions. The regression indicated an increase in permeability with increase in the ratio of sulfated: nonsulfated GAG.

Animals↗
PubMed1991

Age, time since menopause, and body parameters as determinants of female spinal bone mass: a mathematical model.

The study of mathematical models to describe bone mass behavior throughout life is a possibility for assessing the main factors of peak bone mass and bone loss. We developed a mathematical model to predict spinal bone mass behavior on a sample of 181 healthy Italian women whose lumbar bone mineral content was determined by Gd-153 dual photon absorptiometry. This model proved to be both efficient, showing the best fit (r = 0.7 on spinal bone mineral content) when compared to other previously suggested models, and also reliable as its fit remained the best when applied to a subsequent sample of 519 women whose lumbar spine was measured by dual X-ray photon absorptiometry. This model suggests that body height and body weight (but not age) are determinants of bone mass in premenopausal women. In postmenopausal women, an accelerated phase of bone loss starting at menopause is dependent on age and time since menopause, whereas body mass index acts as a protective factor. This model confirms the influence on spinal bone mass not only of age and time since menopause but also of body size parameters.

Absorptiometry, Photon↗
PubMedDate not supplied

Mass spectral behavior and HPLC of some unusual molecular phospholipid species.

The molecular species of the major phospholipids from the marine sponges Parasperella psila and Microciona prolifera were studied using chemical hydrolysis, enzymatic degradation and capillary gas chromatography (GC), high performance liquid chromatography (HPLC), desorption chemical ionization (DCI), fast atom bombardment (FAB) combined with collisionally activated decomposition (CAD) mass spectrometry. Two new solvent systems were developed for the isolation of these species from the sponges. Our investigations indicated the existence of unusual symmetrical phospholipids as major components. 1,2-Di-(5Z,9Z)-5,9-hexacosadienoyl-sn-glycero-3-phosph oethanolamine was found in both organisms, while 1,2-di(5Z,9Z,19Z)-5,9,19-hexacosatrienoyl-sn-gly cero-3-phosphoethanolamine was present in M. prolifera, 1,2-Di-(4Z,7Z,10Z,13Z,16Z,19Z)-4,7,1 0,13,16,19-docosahexaenoyl-sn-glycero-3- phosphocholine was the major molecular species in the PC fraction of M. prolifera.

Animals↗
PubMedDate not supplied

Influence of glycosaminoglycan content of mass transfer behavior of porcine artery wall. Part 1. Diffusive transport of 45Ca2+ and 3HHO.

The diffusion coefficients of Ca2+ and H2O in in vitro porcine arterial tissue were determined to provide a measure of vascular permeability. The effect of anatomical location and diet on the magnitude of that permeability was evaluated. The diffusion coefficient of calcium was found to vary focally and, in addition, pulmonary artery was much more permeable than thoracic aorta. Four months feeding of a high lipid diet did not affect diffusive transport.

Animals↗
PubMed1989

Rats eating and hoarding as a function of body weight and cost of foraging.

Rats were trained to forage 2 h daily in a zigzag alley at -15 degrees C. On experimental days food was placed in large amounts at a 1-, 4-, or 16-m distance from a warm shelter. The mass of food ingested and hoarded in the shelter by the rats was then recorded. The rats' body weights were depressed progressively by spacing the sessions with access to food, and then the animals were allowed to recover their initial body weight. The results showed that 2-h food intake was constant and did not vary as a function of body weight loss or the distance to reach the food (cost). On the other hand, the mass of food hoarded was a linear increasing function of body weight loss below the hypothetical set point for body weight and a decreasing linear function of the distance to the food. The linear regression of the mass of food hoarded on body weight with a negative slope (b) adequately depicted the rat's hoarding behavior: mass hoarded = a + b (body wt). The slope of this function decreased with increasing cost of food procurement. It is concluded that 1) the main response of the rat to starvation is food hoarding rather than ingestion and 2) the estimation of the body weight set point from hoarding is not affected by the costs of food procurement.

Animals↗
PubMed1986

Upper body and centralized adiposity in Mexican Americans and non-Hispanic whites: relationship to body mass index and other behavioral and demographic variables.

Mexican Americans have a higher prevalence of NIDDM, more overall obesity and more centralized adiposity than non-Hispanic whites, but have thus far not been characterized as to whether they have greater upper body adiposity. Waist-to-hip circumferences (WHR, a measure of upper body adiposity) and subscapular-to-triceps skinfold ratios (centrality index, a measure of centralized adiposity) were determined in 725 Mexican Americans and 226 non-Hispanic whites as part of the San Antonio Heart Study, a population-based study of diabetes and cardiovascular risk factors. Mexican American females had higher centrality indices and WHRs than non-Hispanic white females, even after adjustment for demographic (age, menopausal status) and behavioral variables (body mass index, parity, cigarette smoking, alcohol consumption, exercise, and oral contraceptive and estrogen use). Mexican American males had higher centrality indices than non-Hispanic white males, but differences in WHR disappeared after adjustment for overall adiposity (body mass index). Of the demographic and behavioral variables, only age and body mass index were consistently related to regional body fat distribution. The lack of an association between body fat distribution and behavioral variables suggests that genetic factors may play the principal role in determining body fat distribution. Surprisingly, the distributions of centrality index and WHR were relatively independent of one another suggesting that they may be used as distinct, independent predictors of metabolic diseases.

Adipose Tissue↗
PubMed1990

Responding to community-identified suicide clusters: statistical verification of the cluster is not the primary issue.

Establishing the presence of an epidemic is traditionally a first step in any outbreak investigation. For two reasons, however, this has not been a fruitful approach for suicide cluster investigations. First, the data necessary to statistically verify an excess number of suicidal incidents are often lacking or of poor quality. Second, and more important, when a community perceives that it is experiencing a suicide cluster, it is not immediately relevant whether the cluster is statistically significant. The perception of suicide clustering, and the highly charged emotional atmosphere associated with that perception, may dramatically heighten the potentially "contagious" effect of suicide. That the perception of clustering may itself be a risk factor for suicide distinguishes suicide clusters from all other clusters of fatal disease or illness. A community response plan should, therefore, be implemented to identify and refer persons who may be at high risk of suicide, regardless of whether the community-identified suicide cluster is statistically significant. Statistical techniques may be useful at several stages in the investigation and control of apparent suicide clusters, but statistical verification of a community-identified suicide cluster is not appropriate as a starting point for response to the cluster.

Adolescent↗
PubMed1990

[Hygienic standardization of tin level in the air].

Indices reflecting the functional state of the central nervous system, peripheral blood, enzymes and gonads were used in accordance with the toxico-dynamics of substances. Besides, body mass, behavior of animals, pathomorphological and histochemical indices were studied. 5 concentrations of tin chloride were studied: 400, 80, 15, 3 and 0.5 mg/m3. On the basis of an acute experiment (6-1440 h) it has been established, that the concentration-time relationship according to a number of biochemical and physiological parameters on the graph was expressed by direct lines on the double log scale with angles to abscissa from 124.9 degrees (according to blood transaminase activity reduction) up to 138.2 degrees, which allowed to determine the class of danger, safety and cumulation coefficients, threshold and no-effect concentrations of tin chloride under inhalational exposure to it. The lowest no-effect concentration 0.05 mg/m3 is recommended as an average 24-hour MAC and approved by the USSR Public Health Ministry.

Air Pollutants↗
PubMedDate not supplied

Possible role of the serotonergic system in the behavioral effect of massed electroconvulsive shock in rat.

Massed electroconvulsive shock (ECS) inhibited escape in a one-way avoidance system and tolerance to this effect developed in rats shocked for 4 consecutive days (1, 4, 5 and 10 ECS respectively). Chronic treatment with p-bromo-N-methylamphetamine (V-III) as well as pretreatment with pCPA antagonized the behavioral disturbing effect of massed ECS strongly supporting the idea that 5-HT plays an important role in observed behavioral effects.

5-Hydroxytryptophan↗
PubMed1976

Mass spectral and pyrolytic behavior of the two main products of phenylbutazone degradation: simulation of unusual mass spectral fragmentation.

The two major routes of degradation of phenylbutazone (I) are oxidation and hydrolysis. Hydrolysis gives rise to n-butylmalonic acid mono(N,N'-diphenyl)hydrazide (II). Oxidation at the C-4 position yields 1,2-diphenyl-4-n-butyl-4-hydroxpyrazolidine-3,5-dione (III), which is readily hydrolyzed to n-butyltartronic acid mono-(N,N'-diphenyl)hydrazide (IV). Whereas the mass spectra of I, III, and the methyl esters of carboxylic acids II and IV all demonstrate major peaks corresponding to their respective molecular ions, the mass spectrum of II is essentially identical with that of I, suggesting facile dehydration. In the mass spectrum of IV, the peak of highest mass is found at m/e 205; no peak could be perceived corresponding to the molecular ion or to loss of water, carbon dioxide, or both of these elements from the molecular ion. Under normal pyrolytic conditions, II is decarboxylated to N-caproylhydrazobenzene (V) and IV is readily dehydrated to yield III. The mass spectral fragmentation of IV was successfully simulated in the laboratory to give an excellent yield of aniline and alpha-keto-N-caproylaniline (VI) (mol. wt. 205). The probable course of this unusual transformation was elucidated from studies of the accelerated decomposition of IV and derivatives considered as possible intermediates in the degradation process.

Carboxylic Acids↗
PubMed1992

Socioeconomic and behavioral correlates of body mass index in black adults: the Pitt County Study.

BACKGROUND: Obesity is more prevalent among Black women than Black men, but there is little information on the correlates of obesity in Blacks. This study describes the relations of sociodemographic factors and health behaviors to body mass index in a southern, Black population. METHODS: In 1988, a community probability sample of 1784 Black adults, aged 25 to 50, was examined in Pitt County, NC. RESULTS: More women than men were at least 20% overweight (57% vs 36%). The relation of socioeconomic status (a composite of education and occupation) to age-adjusted body mass index level was inverse in women but not in men. Body mass index did not differ with either current energy intake or energy expenditure. Smokers and drinkers had lower age-adjusted levels than non-smokers and abstainers. CONCLUSIONS: Since the excess body mass index levels associated with low socioeconomic status in women could not be explained after controlling for adverse health behaviors, further epidemiologic study of risk factors for obesity in Black women is recommended.

Adult↗
PubMed1978

Mass spectrometry and gas chromatography of trimethylsilyl derivatives of catecholamine related molecules.

The trimethylsilyl derivatives of approximately 50 compounds related in structure to biogenic catecholamines have been studied in terms of their gas chromatographic and mass spectrometric behavior. The electron impact mass spectra of the trimethylsilyl derivatives of 3,4-dihydroxyphenylethylamine, 3,4-dihydroxyphenylacetic acid and 3,4-dihydroxyphenylethylamine and deuterated isotopic variants were compared to determine fragmentation characteristics of the amines, acids, alcohols and amino acids within this class of compounds. Analysis of shifts in the masses of major diagnostic ions in the spectra of structural analogs of these compounds has shown that structural modification of the structure can be identified and localized within these molecules. The gas chromatographic characteristics of these derivatives are reported, in terms of methylene unit values.

Catecholamines↗
PubMed1989

A behavioral quantal theory of brain function: an alternative to Lashley's continuity theory of mass action.

A behavioral quantal theory of brain function is formulated on the basis of a newly discovered step-wise relationship invariably present among the findings of three experiments by Tsai, et al. on the effects of (1) cerebral decortication, (2) cranial x-radiation, as well as (3) insulin, metrazol, and electroconvulsive shocks upon white rats' adaptive behavior during their learning of successive habit reversals and one-trial reversal problems. Confirmatory results from earlier investigators who studied effects of various current strengths of ECS upon learning and retention of various maze habits are also cited in support of the behavioral quantal theory of brain function which is proposed here as a close-up, more refined alternative to Lashley's continuity theory of mass action.

Animals↗