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PubMed1993

The effects of changes in the definitive host environment on the metabolism of Hymenolepis diminuta during growth and maturation.

Flexibility in the metabolism of Hymenolepis diminuta is associated with changing intrinsic requirements during maturation but is also influenced by extrinsic factors, that is, by the nature of the host environment. End-products of carbohydrate metabolism and enzyme activities in worm extracts were used as indicators of metabolic regulation in H. diminuta recovered at various times postinfection. The predominant end-product from 6-day-old worms is lactate, generated by cytosolic glycolysis. As the cestode matures in the host, lactate production by the whole worm decreases and greater amounts of the mitochondrial end-products, succinate and acetate, are detected. A stable, dichotomous carbon flow to lactate, succinate and acetate is observed from 12 days post-infection. A metabolic gradient along the length of individual strobila is also evident. It extends from glycolysis, in the anterior region, to mitochondrial dismutation in the posterior region. The transition from cytosolic to mitochondrial pathways during maturation and along the strobilus is delayed or suppressed in worms recovered from immunosensitized hosts. Four host environments were compared: unsensitized rats, rats immunosensitized with a primary infection of H. diminuta, rats immunosensitized with a primary infection of Nippostrongylus brasiliensis and mice concurrently infected with Heligmosomoides polygyrus. The specific activities of PK and PEPCK in whole worm extracts were similar in 10-, 21- and 35-day-old worms and did not differ in worms isolated from different host environments. However, the PEPCK/PK ratio is high in worms that utilize mitochondrial pathways and low in worms that produce predominantly lactate. LDH activity is high in lactate producers. It is concluded that the pattern of metabolism in H. diminuta is influenced by many effectors in the host environment.

Acetates↗

PubMed1986

Influence of environment on GABA receptors in muricidal rats.

The influence of environment (isolation) on GABA receptor numbers ( [3H]-muscimol binding sites) and affinities was investigated in specific limbic areas known to be involved with the development of muricide. Olfactory bulbs of isolated rats were found to have identical numbers of [3H]-muscimol binding sites whether or not they were muricidal. However, in the olfactory bulbs of the aggregated animals a greater than two-fold increase was found in numbers of [3H]-muscimol binding sites in those rats that were muricidal. In the amygdala muricidal rats had a 32-34% increase in [3H]-muscimol binding sites over non-muricidal rats regardless of environment. In the septum non-muricidal rats had fewer [3H]-muscimol binding sites than muricidal rats and although the trend was evident, statistical vigor was seen only in the aggregated animals. Neither muricide nor isolation significantly influenced [3H]-muscimol binding numbers in the hypothalamus. GABA Ki values were examined in all brain regions and found to be the same in the isolated and aggregated animals whether or not they were muricidal. We concluded that environment appears to influence apparent GABA receptor numbers in the olfactory bulbs and septum whereas muricidal behavior correlates well with an increase in apparent number of GABA receptors in the amygdala. GABA receptors in the hypothalamus were not influenced by either environment or aggression.

Aggression↗

PubMed1988

Environment-dependent sensitization to amphetamine-induced circling behavior.

Sensitization to amphetamine-induced circling behavior in nonlesioned, female rats was studied. Experiments were designed to determine the effects of time spent in the test environment prior to and following the administration of amphetamine and of the time between injections of amphetamine on the environment-dependent nature of the sensitization process. One group of rats was allowed to habituate to the test apparatus prior to injection of the drug. In this group, the drug was administered in the apparatus and the rats remained there for the duration of drug action. Another group of rats was placed in the apparatus only during the time of peak drug action. These rats were administered amphetamine in their home cages and were not allowed time to habituate to the test apparatus. Amphetamine was administered 2 times and injections were separated by either 1 or 7 days. To determine if the sensitization was dependent on the environment in which the drug was previously experienced, one-half of each of these groups of rats were kept in their home cages following the first injection of amphetamine and experienced the effects of the second injection of amphetamine in the test apparatus. The other half experienced the effects of both injections of amphetamine in the test apparatus. Sensitization was found to occur only in rats that experienced the effects of the first drug injection in the test environment.

Analysis of Variance↗

PubMed1988

The dopamine D-2 agonist quinpirole produces environment-specific conditioned activity.

The stimulant effects of various dopamine agonists can become conditioned to the particular environment with which they are repeatedly paired. The present study assessed the ability of the selective dopamine D-2 agonist quinpirole (2.5 mg/kg) to similarly show environment-specific conditioning. Rats in Paired and Unpaired groups (both n = 12) received 12 pairings of a unique environment with quinpirole or saline, respectively. Horizontal and vertical activity were automatically measured during the 60-min sessions. Home cage injections were given after each session and involved administration of saline or quinpirole to rats, whichever they did not have during the session. Intermittent tests for conditioned activity were given wherein both groups received saline prior to being placed in the chambers for 60 min. Quinpirole enhanced horizontal activity. Stimulant effects on vertical activity were also observed although they appeared after an initial suppression of the response. Conditioned activity was observed on the saline tests as the Paired group was significantly more active than the Unpaired group on each measure. The present findings suggest that enhanced stimulation of the D-2 receptor can produce environment-specific conditioned activity. Consequently, researchers using quinpirole should take this factor into consideration, particularly if utilizing chronic drug treatment.

Animals↗

PubMed1992

Conditioned withdrawal in environments associated with the presence or absence of morphine.

An experiment designed to compare conditioned withdrawal in environments associated with the presence or absence of morphine was conducted in hamsters. For some animals, morphine administration was paired with distinctive environmental cues. For other animals, naloxone-precipitated withdrawal was paired with the distinctive environmental cues. For still other animals, naloxone-precipitated withdrawal and the distinctive environmental cues were unpaired. Following 12 days of training, animals were observed for signs of withdrawal (e.g., wet-dog shakes, etc.) in the distinctive environment following vehicle injections. Results indicated that more conditioned withdrawal responses occurred in the environment paired with the absence of morphine (naloxone-precipitated withdrawal) than in the environment paired with morphine administration.

Animals↗

PubMed1983

An organization-environment framework for assessing program implementation.

Evaluations of health programs are typically conducted from a rational bureaucratic framework in which client change and client outcome are seen as logical outcomes of program activity. This paper proposes a theoretical framework for examining organizational consequences of program implementation. Factors in the internal environment (e.g., the hospital) and the external environment (e.g., the community) which contribute to the program's success or failure, are considered. Observational and structured interview data are used to compare two state funded perinatal projects, one an organizational "success" and the other a costly failure. Attributes of external environments which may be important to successful implementation include demand for services, provider competition, access to information, social beliefs, and professional commitment. Important features of the internal environment include host organization commitment and conflict, and structural attributes: complexity, formalization, centralization, and coordination. The paper concludes with theoretically-based questions which serve as guidelines for process evaluation.

California↗

PubMed1990

Growth characteristics of motile Aeromonas spp. isolated from different environments.

The growth of 80 strains of motile Aeromonas spp. derived from environments with temperatures above 25 degrees C and below 15 degrees C, respectively, were examined at five temperatures (5 degrees C, 10 degrees C, 25 degrees C, 37 degrees C and 44 degrees C) and four salt levels (0.05%, 2%, 4% and 6% NaCl). Sixty-one strains were further examined at two pH levels (pH 7.3 and pH 5.3). All strains grew at 25 degrees C and 10 degrees C with the majority of the isolates proliferating from approx. 10(2) to approx. 10(7) cfu/ml within 1 and 3 days, respectively. In contrast, there were significant differences in the proportion of isolates able to grow at 5 degrees C and 37 degrees C depending on the temperature of their source of isolation. The ecological background of the organisms thus influences their thermal growth range and their ability to proliferate at body temperature, a highly significant factor in infective disease. At 25 degrees C and pH 7.3, all strains grew in 0.05% NaCl, 96% grew in 2% NaCl, 96% grew in 2% NaCl while few grew in broth containing 4% or 6% NaCl. Lowering the pH to 5.3 with lactic acid caused a marked increase in the lag phase at 25 degrees C and prevented growth of a large number of isolates at suboptimal conditions. Thus, none of the isolates from warm environments and only 8% of the isolates from cold environments grew at this pH at 5 degrees C. The observed differences in growth optima between strains from different environments are discussed in relation to food- or waterborne infection.

Aeromonas↗

PubMed1995

Polynuclear aromatic hydrocarbons in the United Kingdom environment: a preliminary source inventory and budget.

This paper presents the first attempt to quantify the production, cycling, storage and loss of PAHs in the UK environment. Over 53 000 tonnes of sigmaPAHs (sum of 12 individual compounds) are estimated to reside in the contemporary UK environment, with soil being the major repository. If soils at contaminated sites are included, this estimate increases dramatically. Emission of PAHs to the UK atmosphere from primary combustion sources are estimated to be greater than 1000 tonnes sigmaPAHs per annum, with over 95% coming from domestic coal combustion, unregulated fires and vehicle emissions. It is estimated that approximately 210 tonnes of sigmaPAH are delivered to terrestrial surfaces each year via atmospheric deposition. Therefore, inputs of PAHs to the UK atmosphere outweigh the outputs by a factor of over 4. This may be explained by enhanced particulate deposition near point sources, PAH degradation in the atmosphere and transport away from the UK with prevailing winds. Disposal of waste residues is estimated to contribute a further 1000 tonnes of sigmaPAH per year to the terrestrial environment. It is illustrated that the use of creosote has the potential to release considerable quantities of PAHs to the UK environment. Temporal trends in PAH cycling are then considered. There is good evidence to suggest that air concentrations and fluxes to the UK surface are now lower than at any time throughout this century. Nonetheless, the UK sigmaPAH burden is still increasing at the present time, principally through retention by soils. However, there are marked differences in the behaviour of individual compounds: there is evidence, for example, that phenanthrene concentrations in soils have declined since the 1960s, although soil concentrations of benzo[a]pyrene and other heavier PAHs have continued to increase through this century. Volatilisation of low molecular weight PAHs accumulated in soils over previous decades may be making an important contribution to the current atmospheric burden. The major uncertainties identified by data on this budget are: (1) the lack of PAH concentrations in some environmental matrices; (2) the possible importance of contaminated soils as a major repository and source of PAHs; (3) the lack of emission data (especially vapour phase releases) for some PAH sources; (4) the importance of biodegradation and volatilisation as loss mechanisms for low molecular weight PAHs in soils; and (5) the importance of creosote use in the PAH cycle.

Journal Article↗

PubMed1996

Women, health and the environment.

This paper develops a conceptual framework for gender-sensitive research and policy analysis that centres on women's interaction with the biophysical environment, and the implications of that interaction for their environmental health. The paper reviews the lack of data on women's non-reproductive health, and argues that there is a need for increased research and policy formulation dealing with women's environmental health in both the developing and the developed countries. One important dilemma for most researchers interested in women's environmental health is the lack of an appropriate conceptual model. The paper argues that attention to women's interaction with the biophysical environment within their own life spaces' reveals that women are exposed to the hazards of environmental illness in a manner that is clearly gender-differentiated. The paper reviews the impact of poverty, illiteracy and gender bias on women's life spaces, and argues that the failure to recognize and protect women's life spaces in economic policy and planning commonly leads to "disease environments" for women and their children. Evidence of the impact of such disease environments on women's environmental health is drawn from the urban setting and from women's experience of desertification in Africa and Asia. The paper reviews the policy issues that emerge from this analysis, and makes a series of suggestions for national and international policy and action in support of improvements in women's environmental health.

Developed Countries↗

PubMed1986

Energy metabolism in largemouth bass (Micropterus floridanus salmoides) from stressed and non-stressed environments: adaptations in the secondary stress response.

White muscle proteins, carbohydrates, lipids, adenylates, phosphagen and the AEC, (adenylate energy charge) were measured in bass inhabiting stressful and non-stressful environments. Within an environment, in June stressed bass had higher carbohydrates, while non-stressed bass had lower ATP, total adenylates and AEC. Comparisons between environments revealed: non-stressed bass had higher ATP/ADP and AEC's in May, CrP/ATP in June, and protein in July; while stressed bass had higher carbohydrate in June and lipid in July. Other metabolites varied insignificantly. AEC's of both groups were within the optimal range indicating physiological compensation (adaptation) of energy metabolism (secondary stress response) occurred in bass inhabiting the stressful environment.

Acclimatization↗

PubMed1994

Somatotroph and lactotroph function in relation to growth in six-week-old pigs reared in a hot or cool environment.

The influences of thermal environment and individual growth rate on somatotroph and lactotroph function were examined in 6-week-old barrows reared entirely in a hot (H: 27-32 degrees C, n = 8) or cool (C: 21 degrees C, n = 10) environment. Growth hormone (GH) and prolactin (PRL) cell contents and responses to growth hormone-releasing hormone (GHRH) or thyrotropin-releasing hormone (TRH) were evaluated in cultured pituitary cells from each animal. Plasma GH, PRL, and insulin-like growth factor-1 (IGF-1) concentrations also were monitored. Thermal environment did not affect in vitro GH secretion, cellular GH content, or plasma GH concentrations. Stimulated in vitro GH release (GHRH-basal) and plasma GH were inversely related to average daily gain (ADG, r = -.76, p < .005 and r = -.51, p < .05, respectively). Cellular GH content also declined as ADG increased (r = -.57, p < .05). Plasma IGF-1 concentrations were not affected by thermal environment and were not related to ADG. Pituitary cells from H animals secreted and contained more PRL than cells from C animals (p < .05). Plasma PRL values were correlated with ADG (r = .54, p < .05), but did not differ between thermal groups. Stimulated in vitro PRL (TRH-vehicle) secretion was positively related with ADG only in the H group (r = .97, p < .001). In contrast, cellular PRL content decreased with ADG in cells from the H barrows (r = -.8, p < .05). Lactotroph function was not related to growth in cells from C pigs. In summary, 1) heat enhanced PRL secretion and cell content; 2) growth and somatotroph function were inversely related; and 3) serum PRL and the PRL response to TRH in cells from H barrows were positively related to growth.

Animals↗

PubMed2005

Comparison of Plasmodium falciparum growth in sickle cells in low oxygen environment and candle-jar.

The first successful in vitro cultivation of Plasmodium falciparum in sickle cells in a gas mixture containing 3% oxygen, 4% carbon dioxide and 93% nitrogen has been reported recently, contradicting earlier claims that the parasite does not multiply continuously in sickle cell trait (HbAS) and sickle cell anemia (HbSS) erythrocytes at low oxygen tension. The present study extends that report by growing three P. falciparum strains in erythrocytes from four different sickle cell trait and four sickle cell anemia donors. Because P. falciparum is known to grow normally in sickle cells when incubated in a candle-jar estimated to contain 15-18% oxygen, we have also compared the growth at 3% oxygen with that in a candle-jar. For convenience, we also refer to the 3% oxygen and the candle-jar as low and high oxygen environment, respectively. The three P. falciparum strains were first grown continuously in low oxygen environment for at least 1 month in erythrocytes from one HbAS carrier. These stock cultures were then used to infect erythrocytes from additional three HbAS carriers and four HbSS patients. Results of the experiments showed that parasite growth and hemozoin production in HbAS erythrocytes in low oxygen environment were comparable to those obtained in the candle-jar. There was growth retardation in HbSS erythrocytes in low oxygen environment, but some of the parasites survived and eventually produced high parasitemia levels. Continuous cultivation of different P. falciparum strains in HbAS erythrocytes is necessary for investigation of possible molecular differences between malaria parasites in sickle cells and those in HbAA erythrocytes.

Anemia, Sickle Cell↗

PubMed2005

Predicting long-term outcomes for women sexually abused in childhood: contribution of abuse severity versus family environment.

OBJECTIVE: Child sexual abuse (CSA) has been associated with adverse adult psychosocial outcomes, although some reports describe minimal long-term effects. The search for explanations for the heterogeneous outcomes in women with CSA has led to an examination of a range of CSA-related factors, from the severity of individual CSA incidents to the childhood family environment. This study compares three factors for predicting adult outcomes: a multidimensional CSA Severity Scale, the presence or absence of CSA, and family environment. METHODS: The effect of CSA on adult outcomes was examined among 290 community-dwelling women raised in intact families. Standardized measures and a focused interview were used to collect data, with siblings as collateral informants. RESULTS: Comparison of a multidimensional CSA Severity Scale to a dichotomous measure of the presence or absence of CSA showed that the Severity Scale did not have greater predictive value for adult outcomes than the dichotomous measure, nor was it as parsimonious. Childhood family environment scales added significantly to the predictive ability of the dichotomous measure. CONCLUSION: The specific characteristics of a CSA experience may be less important than the occurrence of CSA and the family environment of women for predicting long-term outcomes.

Adult↗

PubMed2005

Caesarean section on demand: influence of personal birth experience and working environment on attitude of German gynaecologists.

OBJECTIVE: We performed a survey among German obstetricians and gynecologists in order to evaluate the influence of biographic data, working environment and personal birth experience on the attitude towards Cesarean Section on demand. MATERIAL AND METHODS: All 2106 board-certified gynecologists in Baden-Württemberg received an anonymous questionnaire in 2002-2003 concerning attitude towards C-section on demand, biographical data, personal birth experience and working environment. Seven hundred and nineteen questionnaires were returned and entered into statistical analysis. RESULTS: General approval of C-section was in 59% of all participants, with huge statistically significant variations according to age, personal birth experience and working field. When asked for their preferred way of delivery for themselves or their partner after a low-risk pregnancy, 90% of the responding gynecologists opted for vaginal delivery. The approval depended statistically significant on parenthood, personal birth experience and working environment. CONCLUSIONS: Biographical data, personal birth experience and working environment influence the attitude towards elective Cesaran section. Although 90% would chose vaginal delivery for themselves or their partner as best medical practice, 59% of the physicians approve of the general opportunity of C-section on demand. This shows, that not only best medical practice, but also patient autonomy and forensic aspects seem to play an important role.

Attitude of Health Personnel↗

PubMed2007

The need for the "new health geography" in epidemiologic studies of environment and health.

Growth during the past decade in what can be broadly referred to as social and environmental epidemiologic research has been an important contributor to an emerging understanding of environment and health relationships. While the incorporation of geographic information systems as well as concepts such as "neighborhoods" might be viewed as evidence of social epidemiology moving closer to health geography, I argue that the two fields are not well aligned. Health geography has much more to contribute to studies of environment and health, and attention by social epidemiologists to those potential contributions could help rectify this misalignment. This paper suggests a number of geographic perspectives on health and environment that could create useful connections between geography and public health, via social epidemiology. To illustrate this potential, I use an ongoing study of a Texas community exposed to a large petrochemical complex-an inquiry constructed in the mode of social epidemiology - as a case in point. I apply several perspectives and concepts from geography to the case study. Cultural ecology, discourse materialized, political ecology, and territoriality are used to assess the Texas City situation and suggest important types of understandings that can enhance the social epidemiology approach to environment and health. I conclude with a discussion of the prospects for a social epidemiology infused with this type of geographic thought and analysis.

Chemical Industry↗

PubMed2005

Hepatic environment elicits monocyte differentiation into a dendritic cell subset directing Th2 response.

BACKGROUND/AIMS: Dendritic cells (DCs), which play a critical role during immune response, could present alternative differentiation patterns depending on tissue microenvironment. Our aim was to examine the influence of hepatic microenvironment on human monocyte differentiation into DCs. METHODS: Cytology, immunophenotyping, cytokine production and T-cell activation were analyzed in DCs differentiated from human monocytes co-cultured with rat liver epithelial cells (RLEC) or human cells from various tissue origins and compared to control DCs obtained on plastic with GM-CSF/IL-4. RESULTS: RLEC environment promotes DC differentiation in the presence of IL-4 without GM-CSF. These DCs evidence similar expression of MHC-II, co-stimulatory and adhesion molecules than control DCs, but distinct lineage markers defining a CD11c+/CD14+/CD123+ DC subset. This phenotype is common to DCs from RLEC and human liver environment and differs from that obtained with skin or intestine environments. Functionally, they produce IL-10 but not IL-12p70 and favor IL-4/IL-10 secretion by T-cells rather than IFN-gamma. CONCLUSIONS: Our results confirm that tissue niches modulate DC differentiation and demonstrate that hepatic environment influences monocyte differentiation into a DC subset directing Th2 response, a key data for understanding the specialized immune response in liver. They also make RLEC co-culture system useful for studying liver DC functions.

Animals↗

PubMed2006

Methodological challenges in measuring quality care at the end of life in the long-term care environment.

Understanding what constitutes quality end-of-life care from the perspective of the patient, their family, and health care professionals has been a priority for many researchers in the past few decades. Literature in this area has helped describe many of the barriers to measuring the quality of care in various environments, such as the hospital, hospice, and home. However, much of the work to date in defining the domains of quality care at the end of life has not been conducted within the long-term care environment. This environment is expected to provide care to an increasing number of dying persons with the concurrent aging of the population in many Western countries and demand for more formal services. In this review, the methodological issues involved in measuring quality care at the end of life are examined, with specific attention given to the challenges encountered in the long-term care environment.

Humans↗

PubMed2006

Tropical enteropathy protects against Western diseases in environments of poor sanitation.

This hypothesis suggests that tropical enteropathy protects against Western diseases in environments of poor sanitation, and that the absence of tropical enteropathy contributes to the increased incidence of Western diseases in settings of improved sanitation. The hypothesis is supported by four observations: (1) The prevalence of tropical enteropathy is inversely related to the incidence of Western diseases, (2) The bowel is a major immune and neuroendocrine organ, and inflammation of the gut results in profound local and systemic changes, (3) Tropical enteropathy can account for the subtle clinical differences observed between individuals living in third world environments and industrialized societies, and (4) The concept that tropical enteropathy protects against Western diseases in environments of poor sanitation is consistent with the observations upon which the "Hygiene and Fetal Origins Hypotheses" are based. Identifying tropical enteropathy as a mechanism that protects against Western diseases in environments of poor sanitation creates a new testable hypothesis for some of the most common non-communicable diseases of industrialized societies.

Developed Countries↗