SEARCH · PubMed Health

Results for “Environmental selection”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 757 records · Page 42Linked to original sources

PubMed2004

Evidence for genetic control of adult weight plasticity in the snail Helix aspersa.

Phenotypic plasticity and canalization are important topics in quantitative genetics and evolution. Both concepts are related to environmental sensitivity. The latter can be modeled using a model with genetically structured environmental variance. This work reports the results of a genetic analysis of adult weight in the snail Helix aspersa. Several models of heterogeneous variance are fitted using a Bayesian, MCMC approach. Exploratory analyses using posterior predictive model checking and model comparisons based on the deviance information criterion favor a model postulating a genetically structured heterogeneous environmental variance. Our analysis provides a strong indication of a positive genetic correlation between additive genetic values affecting the mean and those affecting environmental variation of adult body weight. The possibility of manipulating environmental variance by selection is illustrated numerically using estimates of parameters derived from the snail data set.

Animals↗

PubMed2005

[An update on the treatment of psychological and behavioral symptoms associated to dementia].

Behavioral disturbances in dementias are relevant because they are very common, they worsen patients' medical and cognitive condition, increase the caregiver burden and accelerate the admission to nursing homes. The different behavioral disturbances in dementias can appear isolated, but in most cases, patients present a combination of disturbances producing one of two main syndromes: the psychotic or the affective syndrome. Proper handling of these behavioral disturbances requires a correct characterization of the syndrome, discarding medical or environmental causes and selecting the drug with the better effectiveness and safety profile for each patient. In spite of the important number of psychotropics available, there is not enough scientific evidence about their real effectiveness and security in patients with Alzheimer's disease. This article reviews recent advances in the treatment of most common and disruptive behavioral disturbances.

Alzheimer Disease↗

PubMed1992

Risk factors for amputation in patients with diabetes mellitus. A case-control study.

OBJECTIVE: To identify and quantify risk factors for lower extremity amputation in persons with diabetes mellitus. DESIGN: Case-control study. SETTING: A Veterans Affairs medical center. PATIENTS: Eighty patients having amputation associated with diabetes and 236 diabetic controls without limb lesions were enrolled before surgery from the 21,167 inpatient care and outpatient surgical patients seen at the Seattle Veterans Affairs Medical Center during a 30-month period. MEASUREMENTS: Selected vascular, neuropathic, environmental, health care, self care, nutritional, metabolic, lifestyle, and psychosocial risk factors were measured in all patients before surgery. RESULTS: Statistically significant risk factors identified from analysis included insufficient mean below-knee and foot cutaneous circulation (odds ratio, 161; 95% CI, 55.1 to 469); ankle-arm blood pressure index less than 0.45 (odds ratio, 55.8; CI, 14.9 to 209); absence of lower leg vibratory perception (odds ratio, 15.5; CI, 8.3 to 28.7); low levels of high-density lipoprotein (HDL) subfraction 3 less than or equal to 0.7 mumol/L (odds ratio, 4.9; CI, 2.9 to 8.3); and no previous outpatient diabetes education (odds ratio, 3.2; CI, 1.6 to 6.6). A logistic regression analysis done to control for the potentially confounding effects of age; race; socioeconomic status; diabetes duration, type, and severity confirmed these findings and added a statistically significant interaction between foot transcutaneous oxygen tension and peripheral vascular disease history. Clinical interventions to alter these risk factors were identified, including aggressive treatment of infection, diabetes education, protective footwear, and preventive footcare. CONCLUSIONS: Multiple risk factors exist along the continuum of conditions and events leading to lower extremity amputation in diabetes. Modification of certain risk factors by patients and health professionals may reduce the risk for amputation and thus decrease the human and dollar costs that accompany limb loss in this prevalent chronic disease.

Adult↗

PubMed1999

[Grey relational analysis on early bolting of Angelica and its main factors].

Selecting the principal environmental and cultivated factors from the main production areas of Angelica sinensis in Gansu, the problem of early bolting were analysed with grey system theory. After the quantitative analysis, the relational grade was: elevation > precipitaton > density of crop > organic fertilizer > phosphorus fertilizer > nitrogen fertilizer. The research would provide scientific basis for check on the rate of the early bolting of Angelica effectively as well as improve the product and benefits.

Altitude↗

PubMed2002

Factors affecting the hatching of human pinworm ova.

Parasite life-history traits reflect past environmental and host selective pressure that act to produce strategies that maximize successful transmission. Pooled human pinworm eggs were pretreated with 0.9% NaCl, acid digestive enzyme, and alkaline solutions (pH 9.0) and then incubated in 0.9% NaCl at room temperature and 37 degrees C both with and without 5% CO2. Eggs pretreated with both acid and base had the same hatching pattern, which was markedly different to that of the untreated eggs. At room temperature (RT), hatching of the pretreated eggs occurred on the first day and reached its peak rate (>90%) on day 3; at 37 degrees C hatching occurred on the second day and was more than 80% by day 5. Hatching of the untreated eggs was evident on day 2 at RT and between days 3-5 at 37 degrees C although in smaller numbers (<20%). The CO2 did not affect the hatching of larvae. The larvae could survive after hatching in 0.9% NaCl for 2 and 4 days at 37 degrees C and 25 degrees C, respectively. The present investigation gives a different information that human pinworm ova can hatch into larvae with or without exposure to acid digestive enzyme or alkaline solutions.

Animals↗

PubMed1992

Use of plastic films in grain stores.

A laboratory study of wheat stored at two different levels of moisture content with and without presence of Sitophilus zeamais Motschulsky was performed. Flexible PVC and polythene films as seals were used in order to examine their effectiveness to maintain the wheat quality by comparing changes in moisture content, germination and weight loss. The PVC film showed a high water vapor permeability and it behaved as the permeable muslin control, keeping the grain quality in all tested conditions. The polythene film showed a low water vapor permeability and it allowed the insects development. It seems that plastic films may be useful in grain stores bearing in mind their properties, adequate sealing and protecting them from insect damage, besides they should be selected according to environmental conditions.

Animals↗

PubMedDate not supplied

[Chiral safety of the biosphere as a biophysical problem].

The biosphere with its inherent chiral asymmetry fixed in the process of biological evolution at the level of L-amino acids and D-hydrocarbons and some other biologically active compounds of biogenic origin is under strong pressure of chiral substances produced by chemical, pharmaceutical, and other branches of industry and agriculture. Effective use of enantiomers is accompanied by toxic and even mutagenic effects of their mirror-image enantiomorphs. Only small amounts of products are tested for chiral purity; there is no system of global biosphere monitoring as well as no common standards of permissible concenrations. The investigation of the molecular basis of chiral stereospecificity of enzymes and cell receptors is of great interest from the point of view of fundamental biophysics. On the other hand, the development of chiral-selective sensors for environmental monitoring is important from the viewpoint of applied biophysics.

Biophysical Phenomena↗

PubMed2006

[Melanocortin 1 receptor (MC1R) gene phylogenetic tree and canine coat colors].

Canines were domesticated approximately 10,000 years ago. The various environmental conditions and selective breeding resulted in abundant diversity of coat colors in domestic canines. Many canine coat colors are affected by melanocortin 1 receptor (MC1R). MC1R genes are homologous among different species. This article reviews the studies on MC1R polymorphism in the domestic canine. We also constructed a phylogenetic tree of MC1R genes by comparing the canine gene with those from nine representative mammalian species. Results show the gene phylogenetic tree accorded with Taxonomy of the ten mammals in the main.

Amino Acid Sequence↗

PubMed2006

[Correlations of blood lead levels in infant, in maternal blood and in breast milk].

OBJECTIVE: To understand the correlation of blood lead levels in infant, in maternal blood and in breast milk as to providing evidence for prevention of potential infant hazard from lead. METHODS: Lead levels were measured by using graphite stove atom absorption spectrographic methods in maternal breast milk, maternal blood and infant blood in infants aged 0 to 11 months and their mothers between November and December 2002 in Xiamen City. Blood samples were collected from both mother and infant's fingertips. Questionnaires were also used to collect information about childbirth, mothers, families and other related environmental factors. RESULTS: All 177 infants and their mothers were enrolled in the study. Infant blood lead levels reached a range from 0.12 micromol/L to 1.36 micromol/L, with a geometric mean (GM) of 0.37 micromol/L. There were 46 infants (21.64%) having blood lead levels over 0.48 micromol/L. And the maternal blood lead levels ranged from 0.21 micromol/L to 2.38 micromol/L (GM = 0.50 micromol/L). Among the 177 infants, 160 (93.8%) were breastfed; breast milk was collected from 105 (63.3%) of these mothers. Infant blood lead level was significantly correlated with the levels of maternal blood lead and breast milk lead, which indicated that maternal blood lead level might influence the infant blood lead levels through the breast milk. Blood lead levels in infants living in old business district and the breast milk lead levels of their mothers were higher than those in any other areas (P < 0.01); partial correlation analysis showed that infant blood lead levels were positively associated with the maternal blood lead level, infant's age and mother's work, and negatively associated with mother's height. CONCLUSION: The infant blood lead levels should not only relate to the maternal blood lead and the breast milk lead levels, so regards should be had to the other environmental factors, when selecting the feeding pattern and family rearing behaviors.

Adult↗

PubMed1991

Current status of mold immunotherapy.

There is evidence to suggest that molds can cause IgE-mediated upper respiratory tract disorders and immunotherapy is efficacious in a select group. The environmental sampling studies show a remarkably small numbers of molds accounting for a majority of the mold load in various diverse locations. These are Cladosporium, Basidiospores, Aspergillus, and Alternaria-Penicillin families. Basidiospores have been underreported in the older studies because of difficulties in their identification. Whether the absolute mold level is the most important factor leading to IgE formation and induction of upper respiratory tract symptoms is uncertain. Certainly, the majority of the studies are based on the assumption that the absolute level of mold in the environment is the most important factor leading to the development of symptoms, but this is not based on strong evidence. A major problem in the majority of the studies is a lack of standardization of extracts which may lead to false negatives on skin testing and thus produce variable data in population evaluations comparing the prevalence of mold to its ability to induce IgE production and symptoms. The best current trials to document the efficacy of mold immunotherapy have been with the standardized Cladosporium extract. Unfortunately, these results cannot be extrapolated to the commercially available mold extracts available in the United States either for immunotherapy or for skin testing. These extracts are highly variable in their potency, prone to high false negative rates, and at best serve as poor skin testing reagents and possibly even worse immunotherapy reagents. Adequately standardized mold reagents are urgently needed to determine whether the Cladosporium data can be extrapolated to them in any meaningful way.

Air Microbiology↗

PubMed1983

Immunoregulation by macrophages II. Separation of mouse peritoneal macrophages having tumoricidal and bactericidal activities and those secreting PGE and interleukin I.

Macrophage subpopulations having bactericidal or tumoricidal activities and secreting interleukin I (IL1) or prostaglandin E (PGE) were identified through primary or secondary infection with Salmonella enteritidis and separated by sedimentation velocity. Bactericidal activity was measured by [3H]-thymidine release from Listeria monocytogenes and tumoricidal activity by 51Cr-release from C-4 fibrosarcoma or P815 mastocytoma cells. Macrophages with bactericidal activity were distinguished from those with tumoricidal activity a) during secondary infection when cytolytic activity occurred only at days 1-4 post injection and bactericidal activity remained high throughout and b) after sedimentation velocity separation. Cytolysis was consistently greatest among adherent cells of low sedimentation velocity, whereas cells with bactericidal activity increased in size during the infection. Tumour cytostasis (inhibition and promotion of [3H]-thymidine uptake) differed from cytolysis in that the former was more prolonged during infection and was also detected among large cells. Secretion of immunoregulatory molecules PGE and IL1 occurred maximally among different macrophage subpopulations separated by sedimentation velocity and depending on the type of stimulus used in vitro. There was an inverse correlation between IL1 production and PGE production after stimulation with C3-zymosan or lipopolysaccharide (LPS). The development of immunity during infection may therefore be dependent upon the relative proportions of effector and regulatory macrophage subpopulations and the selective effects of environmental stimuli on these functions.

Animals↗

PubMedDate not supplied

An approach to the detection of malnutrition in rural children using socio-economic indices and level of education of mother as proxy.

The hypothesis that social indices and educational level of mother are potential sources of childhood malnutrition was tested in Kampumbu, Zambia. Hemoglobin, hematocrit, protein and albumin levels in children were studied in relation to malnutrition. Six hundred and fifty rural children (306 males and 344 females) aged one and fourteen years exposed to various types of diet and environmental factors were selected randomly. Data on economic status, diet environment and educational attainment as well as other demographic information were collected. The major epidemiological findings were that the difference in the distribution of malnourished children by socio-economic status (as measured by income) and hypochromotrichia, oedema or stomatitis was significant (X2 = 4.1, P less than 0.025), and the relative odds were significantly greater than unity at 0.05 level. Similarly, there was a very significant difference (X2 = 7.4, P less than 0.005) in the distribution of malnourished children by socio-economic status (as measured by house grades) and hypochromotrichia, oedema or stomatitis. The estimated relative odds were significantly greater than unity at 0.05 level. Other variables, including age, history of hookworm, were not found to be determinants of risk for malnutrition.

Adolescent↗

PubMed1980

Contribution of patient and hospital characteristics to adverse patient incidents.

The 1974 medical malpractice "crisis" brought about extensive legislation and insurance regulation in the United States. Hospitals in many states are now required to support risk management programs that include investigation and systematic analyses of adverse patient incidents. However, no research supports the hypothesis that systematic analysis of adverse patient incidents can identify contributory factors. In this study, a simple prediction model was used to estimate relationships between adverse incidents and selected patient and environmental characteristics in a large hospital. While some of the incident-characteristic relationships were significant, none of the estimated equations yielded results that could be logically translated into policy recommendations for the hospital. These results point to the need for further research. The benefits that positive research results would have for patients, hospitals, an the bill-paying public are obvious. Additional negative results would suggest that many legislative bodies and regulatory agencies were presumptions in requiring hospitals to conduct analyses of incidents.

Accident Prevention↗

PubMed1994

[Construction and validation of an index of psychosocial adjustment in intensive care without interviewing the patient. Group of Researchers of the ASCI (social support in intensive care) Project].

BACKGROUND: Psycho-social support factors play an important role in the health status of the community. Their effect on the clinical course of critically ill patients is poorly known. One of the main obstacles for their study is the difficulty of the measurement of psychosocial factors in the critical care environment. The objective of this study is to build-up and validate an instrument to assess the psycho-social adjustment in critical care patients. METHODS: We have studied 214 adult patients admitted to the intensive care unit (ICU) in a public hospital with 420 beds. None of them was in coma or showed signs of encephalopathy or acute psychosis. Each patient was independently evaluated by two nurses that rated 15 variables related to the patient's psychosocial environment, without direct interview of the patient. The inter-observer concordance was assessed using the weighted kappa index. The internal consistency of the selected items was assessed by the Cronbach's index. RESULTS: The inter-observer concordance in the assessment of the different items was always higher than 0.4. The classical analysis of the internal consistency selected 7 items (environmental confidence, perceived family-support, refusal of the critical situation, irritation, affliction, empathy and liking) which showed an alpha coefficient of 0.77. The psychosocial adjustment scale built upon these 7 items showed a good inter-observer concordance (kappa = 0.71). CONCLUSIONS: Critical care nurses can reliably assess some psychosocial variables in critical care patients. These assessments allows the building of a scale of psychosocial adjustment in the ICU applicable to a wide variety of critical patients and that does not requires direct interview of the patient.

Adaptation, Psychological↗

PubMed1993

Antimicrobial therapy in periodontics.

Cause-related therapy in periodontics is aimed at the reduction or elimination of microbial pathogens. Periodontitis is associated with microflorae which may consist of indigenous, exogenous or superinfecting organisms. In general, periodontal infections due to indigenous organisms (endogenous or commensal infections) are treated by continual reduction of the bacterial load, exogenous infections (true infections) by adjunctive antibiotic therapy and superinfections (opportunistic infections) by a combined approach of conventional therapy and improvement of compromising host or environmental factors. Properly selected single drug, combination drug and serial drug therapies show great promise in the treatment of severe periodontitis

Amoxicillin↗

PubMed1996

A strategy for the evaluation of sensory and pulmonary irritation due to chemical emissions from indoor sources.

Sensory and pulmonary irritation are physiological responses to chemical exposure which result in characteristic, measurable changes in respiratory activity in mice. A standard method has been applied to the estimation of sensory irritation associated with a specific chemical exposure. This method has been correlated with human responses to these chemicals. Symptoms associated with chemical irritants are consistent with complaints due to problems with indoor air quality, which may include eye and upper respiratory tract irritation, headaches, and nausea. A stepwise strategy for assessing the contribution of indoor products to sensory and pulmonary irritation is discussed in the current paper. The strategy includes product emissions testing using dynamic environmental chambers, the selection of suspected irritants for respiratory irritation testing, respiratory irritation testing of individual compounds are representative mixtures using synthesized atmospheres, and the evaluation of test data to determine those compounds which may contribute to sensory and pulmonary irritation in humans. The current strategy is being applied to evaluate carpet system materials and their constituent chemicals.

Air Pollution, Indoor↗

PubMed1996

Clinical overview of instability in the elderly.

Falling is often a multifactorial syndrome that can be viewed from several perspectives, including pathophysiologic, biomedical, functional, and ecologic models. The history, physical examination, and performance testing are the cornerstones of evaluation. Diagnostic testing in selected cases and environmental evaluation when feasible are additional elements. Management is directed toward correcting reversible problems, improving deficits amenable to partial correction, and providing adaptation to fixed deficits.

Accidental Falls↗

PubMed1996

[Development of minimal requirements for site assessment and monitoring to estimate exposure in environmental medicine--the Hamburg approach].

As a further step towards quality management in environmental medicine the Hamburg Association of Panel Physicians and the Hamburg Department of Labour, Health and Welfare developed a consensus paper concerning the handling of indoor related problems. It focuses on the cooperation between environmental physicians and engineers. A critical point in the process of environmental health risk assessment is the selection of either human biomonitoring or environmental monitoring. Further well-known problems are quality of measures and process documentation. Accurate, reliable measures of individual exposure are an essential need for physicians who have to judge the potential impact of environmental contaminants on human health. The approach proposed in this paper was chosen to enable the patient and the physician to benefit from the special knowledge of environmental engineers on indoor related problems. The procedure and criteria might help to reduce misclassifications of diseases and the amount of measures with no medical relevance and to establish scientifically valid associations between health outcomes and exposures to environmental contaminants.

Air Pollution, Indoor↗