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PubMed2006

Maternal household crowding during pregnancy and the offspring's risk of schizophrenia.

BACKGROUND: Animal models of schizophrenia suggest a link between maternal crowding during pregnancy and increased risk of the offspring to develop physiological, developmental, and behavioral abnormalities that are comparable to those observed in schizophrenia. We tested the hypothesis that a similar link is present in humans. METHOD: We investigated whether prenatal exposure to household crowding was associated with the risk of schizophrenia in a sub-cohort of the Jerusalem Perinatal Study (JPS) consisting 11,015 individuals born between 1964 and 1976. During these years mothers participated in face to face interviews in early pregnancy. The prenatal and birth data, including the number of rooms and individuals living in the mothers' household, was cross-linked with the Israel Psychiatric Registry by ministry personnel. RESULTS: 104 schizophrenia cases were identified in the cohort. Offspring who, while in utero, their mother resided in a household with five or more individuals had RR of 1.47 (95% CI: 0.99-2.16, p=0.05) to develop schizophrenia, compared to those whose mother resided with four or fewer individuals. However, when adjusted for paternal age, the RR was reduced to 1.18 (95% CI: 0.76-1.84, p=0.46). The number of rooms in the household and the household crowding during pregnancy did not significantly impact the offspring's risk to develop schizophrenia. CONCLUSION: The link between maternal household crowding during pregnancy and the offspring's risk of schizophrenia was explained primarily by the impact of paternal age. The authors discuss the results in view of findings from animal and human studies.

Cohort Studies↗
PubMed2002

Effects of phenoxyethanol on the innate immune system of gilthead seabream (Sparus aurata L.) exposed to crowding stress.

Phenoxyethanol is routinely used in seabream aquaculture to minimise fish stress response despite the secondary negative effects which have been observed. In this study, two different doses (60 and 200 microl/l) of phenoxyethanol, sedative and narcotic, were tested for their ability to reduce the stress caused in gilthead seabream (Sparus aurata L.) by crowding. Blood glucose and serum cortisol concentrations were measured as stress indicators. In order to study the effects of the treatment on the innate immune system of crowded specimens, two parameters of the innate immune response, serum complement activity and phagocytosis, were assessed. The results show that anaesthesia itself produced a stress response in the fish and affected the immune system, although the effects were greater with the narcotic dose. When the effects of anaesthesia on crowded fish were analysed, the results pointed to a slight reduction in stress as a result of the sedative dose of phenoxyethanol (lower increase in cortisol and lower reduction in phagocytosis). However, additive negative effects were seen in crowded fish when the narcotic dose of phenoxyethanol was used. Since the use of phenoxyethanol is a common practice in aquaculture, the significance of the results should be considered.

Anesthetics↗
PubMed1979

Effects of resource availability and importance of behavior on the experience of crowding.

According to the interference formulation, participants in a crowded setting will experience interference to the extent that behavioral goals conflict with environmental conditions. The importance of the behavioral goals directly affects not only the magnitude of the interference but also the mechanism by which people cope with interference. It was reasoned that important goals would induce a more active coping strategy in a crowded setting than in an uncrowded setting and would maintain task performance at the price of increasing crowding stress. When the behavioral goal is unimportant, decrements in task performance preclude a rise in stress. A laboratory study manipulated group size, in order to vary the availability of resources, and the importance of the task behavior. The predictions were confirmed, and partial confirmation was obtained for predictions involving the effects of the internal-external personality dimension. The meaning of the results is discussed in terms of other findings in the literature on crowding and the mediating role of the type of mechanism used to cope with interference.

Adaptation, Psychological↗
PubMed1993

Household crowding and social support: a quasiexperimental analysis.

People often cope with crowded living conditions by socially withdrawing from their housemates. This coping strategy may overgeneralize, influencing social interactions with others outside the home. In a stressful laboratory situation, Ss from crowded homes, in comparison with uncrowded counterparts, are less likely to seek support from a confederate and rate the confederate as less supportive. Moreover, Ss from crowded homes are less likely to offer support to a confederate in need. These differences in social interaction behaviors appear to be attributable to crowded residents' social withdrawal.

Adult↗
PubMed2003

Hospital and emergency department crowding in the United States.

Every emergency physician in the United States and, for that matter, in many countries around the world recognizes that the demand for timely access to quality emergency care is one that patients highly value. Unfortunately, hospitals in the USA have become stretched beyond capacity, resulting in overloaded emergency departments, diverted ambulances, and greater risks for patients and providers. Some of the causes and consequences of emergency department crowding are unique to the USA health care system, while others are common to countries throughout the world. The goals for this paper are to provide a brief overview of hospital and emergency department crowding in the USA, to identify commonly cited causes of the problem, and to outline future directions in the search for solutions. A large number of hospitals, inpatient beds, and emergency departments have closed during the past 10 years in the USA. In 1992 there were around 6000 hospitals with emergency departments and there are now less than 4000. While hospitals scrambled to decrease an excess supply of inpatient beds, the demand for emergency department care steadily rose. Between 1992 and 2000, the annual number of emergency department visits in the USA increased from 89.8 to 108 million. While some areas of the USA have been affected more seriously than others (particularly the coasts), almost every state has reported problems with boarding of inpatients in the emergency department. Inpatient boarding is the most frequently cited reason for emergency department crowding within the emergency medicine community. United States hospitals are also struggling with a shortage of health care professionals, particularly registered nurses. There are several policy issues that must be addressed to alleviate hospital and emergency department crowding over the long term. We list these as 'long-term' goals simply because policy changes, in the USA, are often incremental and rarely occur quickly. In order to achieve any of these changes in policy over the long term, advocates for reform must aggressively pursue them today.

Crowding↗
PubMed1972

Lasting biological effects of early environmental influences. 8. Effects of neonatal infection, perinatal malnutrition, and crowding on catecholamine metabolism of brain.

The effects of neonatal infection, perinatal malnutrition, and crowding on the metabolism of brain catecholamine were studied in specific pathogen-free mice. Metabolic turnover of catecholamine was determined by measuring the incorporation of precursor tyrosine-(14)C into brain tissue, catabolic activity of norepinephrine-(3)H at various times after intracisternal injection, and tissue levels of dopamine and norepinephrine. The rate of tyrosine incorporation was decreased by neonatal infection but was increased by perinatal malnutrition and crowding. There was no difference in catabolic activity of norepinephrine between infected, crowded, and control groups. In the malnourished group, however, the total radioactivity from norepinephrine was significantly higher than in the control group (1/2) and 2 hr after injection. The brain contents of dopamine and norepinephrine were depressed in the malnourished group. There was no significant difference in catecholamine levels between infected, crowded, and control groups. In the malnourished group, treatment of the mothers with growth hormone prevented almost completely weight loss during lactation, and also resulted in higher fetal weight. Hormone treatment restored to normal the levels of brain catecholamine and the enzymatic activity of brain tyrosine hydroxylase in progeny of malnourished mothers.

Animals↗
PubMed2004

Household crowding index: a correlate of socioeconomic status and inter-pregnancy spacing in an urban setting.

OBJECTIVES: This paper examines the effect of household crowding on inter-pregnancy spacing and its association with socioeconomic indicators, among parous mothers delivered in an urban environment. DESIGN: Cross sectional survey. METHODS: Sociodemographic data were obtained on 2466 parous women delivering at eight hospitals in Greater Beirut over a one year period. Statistical methodology comprised Pearson chi(2) test and logistic regression analysis. MAIN RESULTS: A significant inverse relation was observed between household crowding and socioeconomic status, defined as education and occupation of women and their spouses. Inter-pregnancy spacing increased with higher levels of crowding. Further analysis suggested that this positive association was confounded by maternal demographic characteristics. CONCLUSIONS: These data have shown that household crowding, a correlate of low parental socioeconomic status, is associated with longer birth intervals. This association, however, seems to be largely explained by maternal age and parity.

Adolescent↗
PubMed1990

A crowding index for finite populations.

The classical definition of population density used in social science disciplines as a measure of density or physical crowding has severe shortcomings since actual spatial orientation is disregarded. A formula is proposed to measure physical crowding or population density which corrects the deficiency of the conventional formulation. As a generalization of the Euclidean distance formula, the proposed index measures relative population density as a function of spatial orientation and size of geometric area. Three mathematical properties of the index stated as conjectures have been supported by Monte Carlo simulations. The formula is evaluated and justified on three key scientific criteria: parsimony, mathematical soundness and empirical verifiability. Crowding is an obvious problem in the small compartmentalized workspaces of U.S. Navy nuclear submarines. The measurement of physical crowding by use of the proposed formula in Concepts of Operations Experiments conducted at the Newport Laboratory of the Naval Underwater Systems Center is reported and discussed.

Adaptation, Psychological↗
PubMed1995

Zero effect of crowding on arousal and performance: on 'proving' the null hypothesis.

This study examined the effect of crowded versus uncrowded conditions upon pulse and self-rated arousal, and upon verbal production performance in subjects' first and second languages. Participants were 52 francophone college students. Arousal estimates were identical for crowded and noncrowded conditions as was verbal performance, thereby contradicting the theories of Zajonc (1965) and Freedman and Perlick (1979) in which crowding is viewed as an activating and intensifying stimulus. Crowding itself appears to have no direct effect on arousal or behaviour as measured.

Adolescent↗
PubMed2003

Repeated handling, restraint, or chronic crowding impair the hypothalamic-pituitary-adrenocortical response to acute restraint stress.

The purpose of the present study was to assess whether, and to what extent prior handling, restraint or social crowding stress during 3-10 days affects the hypothalamic-pituitary-adrenocortical (HPA) response to an acute short-lasting restraint stress. Also the effect of a feedback inhibitory mechanism of corticosterone in the impairment of HPA axis by these stressors was investigated. Male Wistar rats were pretreated with handling 1 min/day for 3-10 days, restraint 2 times daily for 3-7 days and crowding stress for 7 days before exposure to acute restraint stress in metal tubes for 10 min. Some group of rats received exogenous s.c. corticosterone either once 25 mg/kg or 2 times daily 10 mg/kg for 3-10 days before restraint stress. After the last restraint the rats were decapitated and their trunk blood was collected for the measurement of plasma ACTH and serum corticosterone levels. Handling for 3-7 days, restraint for 3-7 days, and crowding for 7 days and a single pretreatment with corticosterone--all significantly and to a similar extent inhibited the restraint stress-induced increase in ACTH and corticosterone secretion. Chronic pretreatment with corticosterone blunted the restraint stress-induced increase in HPA axis activity. These results indicate that repeated short-lasting stress induced by handling, restraint, or crowding potently attenuates the acute restraint stress-induced stimulatory action of the HPA axis. They also indicate adaptive action of moderate stress on the HPA axis response to acute stress. The results also suggest that a short-lasting hypersecretion of corticosterone during psychological stress may induce a prolonged feedback inhibition of the HPA axis activity. The attenuation of HPA axis response by prior handling has also obvious methodological implications.

Adaptation, Physiological↗
PubMed2006

The involvement of nitric oxide and prostaglandins in the cholinergic stimulation of hypothalamie-pituitary-adrenal response during crowding stress.

The aim of the present study was to determine the effect of social crowding stress and significance of nitric oxide (NO) and prostaglandins (PG) generated by constitutive and inducible nitric oxide synthase (NOS) and cyclooxygenase (COX) in the stimulation of hypothalamic-pituitary-adrenal (HPA) axis by cholinergic muscarinic receptor agonist carbachol. Inhibitors of neuronal NOS (nNOS) L-NNA, general NOS L-NAME and inducible NOS (iNOS) aminoguanidine, as well as inhibitors of COX-1, piroxicam, and COX-2, compound NS-398 were administered 15 min prior to carbachol to control or crowded rats (24 rats in cage for 7, during 3 and 7 days). In stressed rats L-NAME, L-NNA and aminoguanidine significantly intensified the carbachol-induced ACTH and corticosterone secretion, like in control rats. Piroxicam, markedly decreased the carbachol-induced ACTH and corticosterone response under either basal or stress conditions. Compound NS-398 did not markedly alter the carbachol-induced HPA response in control and stressed rats. Crowding stress (3 days) significantly impaired the i.c.v. prostaglandin E(2)-induced ACTH response. Corticotropin releasing hormone (CRH) receptor antagonists, alpha-helical CRH [9-14], given i.c.v. did not alter the PGE(2)-evoked corticosterone response in either control or stressed rats, indicating that hypothalamic CRH is not involved in the PGE(2)-induced central stimulation of HPA axis. In control rats L-NAME considerably enhanced, while L-arginine, a physiological NOS substrate, abolished the PGE(2)-induced ACTH and corticosterone response. In stressed rats this NOS blocker significantly increased and L-Arg reduced the stimulatory effect of PGE(2) on ACTH and corticosterone secretion. The carbachol-induced corticosterone response was significantly increased by pretreatment with nNOS inhibitor L-NNA and was considerably reduced by indomethacin, a general COX inhibitor. Pretreatment with both antagonists left the carbachol-induced corticosterone level unchanged, suggesting an independent and reciprocal effect of NO and PG in the cholinergic stimulation of pituitary-adrenocortical response. These results indicate that in the stimulatory action of muscarinic agonist, carbachol, NO is an inhibitory transmitter under basal and crowding stress conditions. This psychosocial stress does not functionally affect the NOS/NO systems. Prostaglandins are involved in the cholinergic muscarinic-induced stimulation of HPA response to a significant extent in non-stressed rats. PGE(2) may be involved in the carbachol-elicited HPA response under basal and stress conditions. Prostaglandins released in response to muscarinic stimulation did not evoke the hypothalamic CRH mediation. NO significantly impairs and PG stimulates the carbachol-induced HPA response in rats under basal and social stress conditions.

Acetylcholine↗
PubMed1991

Social hassles and psychological health in the context of chronic crowding.

Data are presented on the interactive effects of an enduring environmental stressor with acute, daily social stressors on psychological distress. A cross-sectional study of males in urban India and a longitudinal study of male and female American college students examined the interplay of these two types of stressors. In India, social hassles in the home predicted psychological symptoms only among residents of crowded homes, after statistically adjusting for income. In America, the interaction between social hassles and crowding was replicated in analyses adjusting for prior psychological symptoms, prior social acquaintanceship with housemates, and income. A six-month follow-up study with the American sample replicated the interaction. In all three analyses of the social hassle-crowding interaction, there was a main effect of crowding but no main effect of social hassles on psychological symptoms. These findings suggest that some chronic environmental stressors may increase the impact of acute social stressors, and highlight the importance of examining contextual factors in the stress and health process.

Adult↗
PubMed1998

Traumatic asphyxia following stadium crowd surge: stadium factors affecting outcome.

BACKGROUND: Stadium crowd surges frequently occur following major athletic events. A recent crowd surge injured more than 80 persons by trampling and/or crushing. This incident was reviewed to identify injury patterns consistent with crush-related injury. In addition, the incident was reviewed to determine which stadium policy and design factors may have potentiated this event. METHODS: A recent crowd surge occurred following a college football game. This resulted in 86 people being transported to the University of Wisconsin and other area hospitals. All charts were reviewed to evaluate patient outcomes. The stadium was examined as were security system video tapes to evaluate stadium factors that contributed to this event. Current policies were obtained through the university sports administration. RESULTS: Of 86 patients transported for evaluation of stadium-related injuries, 10 were treated for traumatic asphyxia. Other injuries requiring hospital admission included musculo-skeletal trauma in two patients and one grade II liver injury. Six others were admitted overnight for observation. Several stadium factors were identified that contributed to the event, and appropriate changes in crowd control policies and stadium design were instated to prevent recurrence. CONCLUSIONS: This report details the largest single report of traumatic asphyxia second to the England Hillsborough disaster. Several stadium factors were identified that resulted in crush-related injury. Cooperative review and modification of stadium policies and design may prevent such events in the future.

Adolescent↗
PubMed1998

Chronic residential crowding and children's well-being: an ecological perspective.

Chronic residential crowding is associated with difficulties in behavioral adjustment at school, poor academic achievement, heightened vulnerability to the induction of learned helplessness, elevated blood pressure, and impaired parent-child interpersonal relationships among a sample of working-class, 10-to 12-year-old children living in urban India. The significant main effects of residential crowding on blood pressure and learned helplessness are moderated by gender. Residential crowding is positively associated with blood pressure only among boys and with helplessness only among girls. All analyses statistically control for household income. We then demonstrate that perceived parent-child conflict functions as an underlying, intervening process that largely accounts for several correlates of household crowding among children.

Child↗
PubMed2006

Effect of crowding by dextrans and Ficolls on the rate of alkaline phosphatase-catalyzed hydrolysis: a size-dependent investigation.

The cell cytosol is crowded with macromolecules such as proteins, nucleic acids, and membranes. The consequences of such crowding remain unclear. How is the rate of a typical enzymatic reaction, involving a freely diffusing enzyme and substrate, affected by the presence of macromolecules of different sizes, shapes, and concentrations? Here, we mimic the cytosolic crowding in vitro, using dextrans and Ficolls, for the first time in a variety of sizes ranging from 15 to 500 kDa, in a concentration range 0-30% w/w. Alkaline phosphatase-catalyzed hydrolysis of p-nitrophenyl phosphate (PNPP) was chosen as the model reaction. A pronounced decrease in the rate with increase in fractional volume occupancy of dextran is observed for larger dextrans (200 and 500 kDa) in contrast to smaller dextrans (15-70 kDa). Our results indicate that, at 20% w/w, smaller dextrans (15-70 kDa) reduce the initial rate moderately (1.4- to 2.4-fold slowing), while larger dextrans (>200 kDa) slow the reaction considerably (>5-fold). Ficolls (70 and 400 kDa) slow the reaction moderately (1.3- to 2.3-fold). The influence of smaller dextrans was accounted by a combination of increase in viscosity as sensed by PNPP and a minor offsetting increase in enzyme activity due to crowding. Larger dextrans apparently reduce the frequency of enzyme substrate encounter. The reduced influence of Ficolls is attributed to their compact and quasispherical shape, much unlike the dextrans.

Alkaline Phosphatase↗
PubMed1990

The influence of macromolecular crowding on thermodynamic activity: solubility and dimerization constants for spherical and dumbbell-shaped molecules in a hard-sphere mixture.

Macromolecules in solution can have large effects on the properties of other solutes through nonideal excluded-volume (crowding) interactions. Minton has calculated such effects by treating the macromolecules as a hard-sphere fluid in a background of an inert structureless solvent. In the present paper these calculations are extended by including the primary solvent as a separate component in a hard-sphere mixture. The results are in good agreement with experimental data. However, some predictions of this model differ drastically from those based on Minton's approach. Thus, much smaller effects from macromolecular crowding, particularly by smaller molecules, are expected. The present results also predict a much larger dependence on the shape of the molecules under study; notably for a dimerization reaction, it is found that the excluded-volume effects actually can destabilize side-by-side binding of two spherical molecules, while a dimerization to a spherical complex is stabilized. Therefore there will exist intermediate shapes of complexes whose stability is insensitive to crowded-volume effects. The consequences for crowding effects inside the living cell are also discussed.

Macromolecular Substances↗
PubMed2005

Influence of macromolecular crowding upon the stability and state of association of proteins: predictions and observations.

The concept of excluded volume and possible effects of excluded volume on the reactivity of macromolecules in highly volume-occupied or "crowded" media are introduced and briefly summarized. Theoretical and experimental studies of the effect of crowding on protein folding and unfolding, and on the effect of crowding on protein association and aggregation, are reviewed. Possible effects of the effect of crowding on an initially native protein that can undergo unfolding, self-association of native protein, and/or aggregation of non-native protein are considered.

Biopharmaceutics↗
PubMed1999

Molecular crowding and viscosity as determinants of translational diffusion of metabolites in subcellular organelles.

The role of molecular crowding and viscosity on the apparent translational diffusion coefficient (ADC) of small metabolites was investigated in different subcellular organelles using the pulse-field gradient spin-echo 1H NMR technique. ADCs of metabolites with increasing radius of gyration (0.7 A < RG < 4.5 A) were measured in the cytoplasm of rat or chicken erythrocytes, in the nucleus of chicken erythrocytes, and in isolated rat liver mitochondria. Metabolite ADCs in these systems were compared with the corresponding ADCs determined in model solutions of increasing bulk viscosity but different molecular crowding. For solutions having the same viscosity, metabolite ADCs decreased with increasing concentration of cosolutes. This effect is adequately described by the modified Stokes-Einstein relationship, ADC = k/RG (1 + 2.5Phi), where k is a constant for a given temperature and Phi is an obstruction factor reporting the fractional volume of solution occupied by cosolutes, a measure of the molecular crowding in the solution. Cytoplasmic values of Phi for metabolites of different sizes did not depend exclusively on metabolite RG but on additional factors including the chemical nature of the metabolite, the presence of diffusional barriers, and metabolite-specific binding sites. In the case of water, nuclear Phi values approached those of the extracellular space while mitochondrial Phi values were significantly higher than those of the cytoplasm. Taken together, these results reveal important differences in molecular crowding within the different subcellular compartments, suggesting considerable diffusional heterogeneity for small metabolites within the different intracellular organelles.

Animals↗