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PubMed2001

An analysis of consultations with the crowd doctors at Glasgow Celtic football club, season 1999-2000.

OBJECTIVE: To analyse all clinical presentations to the crowd doctors at Scotland's largest football stadium over the course of one complete season. METHODS: A standard clinical record form was used to document all consultations with the crowd doctors including treatment and subsequent referrals. The relevance of alcohol consumption was assessed. RESULTS: A total of 127 casualties were seen at 26 matches, a mean of 4.88 per match. Twenty casualties were transferred to hospital, including one successfully defibrillated after a cardiac arrest. Alcohol excess was a major contributing factor in 26 cases. CONCLUSIONS: The workload of the crowd doctors was very variable and diverse. The social problem of excessive alcohol consumption contributed considerably to the workload. The provision of medical facilities at football grounds means that attendance there is now one of the least adverse circumstances in which to have a cardiac arrest. The study confirmed previous impressions that more casualties are seen at high profile matches.

Adolescent↗
PubMed1984

Effect of crowding on emotional reactivity in male rats.

The effect of two different population densities (3 and 9 animals/cage) on emotional reactivity, measured by their performance in an exploratory box, and pituitary-adrenal response to acute noise stress are compared. The crowded rats showed a higher defecation rate and lower exploratory activity than the control rats. Adrenocorticotropin (ACTH) response to noise was higher in the crowded than in the control rats. The results clearly indicate that crowding increased emotional reactivity in adult male rats.

Adrenal Glands↗
PubMed2004

Crowding: risk factor or protective factor for lower respiratory disease in young children?

BACKGROUND: To study the effects of household crowding upon the respiratory health of young children living in the city of São Paulo, Brazil. METHODS: Case-control study with children aged from 2 to 59 months living within the boundaries of the city of São Paulo. Cases were children recruited from 5 public hospitals in central São Paulo with an acute episode of lower respiratory disease. Children were classified into the following diagnostic categories: acute bronchitis, acute bronchiolitis, pneumonia, asthma, post-bronchiolitis wheezing and wheezing of uncertain aetiology. One control, crudely matched to each case with regard to age (<2, 2 years old or more), was selected among healthy children living in the neighborhood of the case. All buildings were surveyed for the presence of environmental contaminants, type of construction and building material. Plans of all homes, including measurements of floor area, height of walls, windows and solar orientation, was performed. Data were analysed using conditional logistic regression. RESULTS: A total of 313 pairs of children were studied. Over 70% of the cases had a primary or an associated diagnosis of a wheezing illness. Compared with controls, cases tended to live in smaller houses with less adequate sewage disposal. Cases and controls were similar with respect to the number of people and the number of children under five living in the household, as well the number of people sharing the child's bedroom. After controlling for potential confounders, no evidence of an association between number of persons sharing the child's bedroom and lower respiratory disease was identified when all cases were compared with their controls. However, when two categories of cases were distinguished (infections, asthma) and each category compared separately with their controls, crowding appeared to be associated with a 60% reduction in the incidence of asthma but with 2 1/2-fold increase in the incidence of lower respiratory tract infections (p = 0.001). CONCLUSION: Our findings suggest that household crowding places young children at risk of acute lower respiratory infection but may protect against asthma. This result is consistent with the hygiene hypothesis.

Acute Disease↗
PubMed1980

Differential effects of spatial crowding and sex on behavior.

This study examined the nature of the interaction of the spatial variables, number of people in a group and density, with sex of subject as it affects the experience of crowding and behavior. A 3 X 2 factorial design was employed; the independent variables were spatial crowding and sex, and the dependent variables, measures of performance on a memory task, perceived comfort, and perception of the environment. 90 males and 90 females were tested in homogeneous sex groups in one of three conditions: (a) 30 subjects per group, (b) 6 subjects sitting as close together as (a), and (c) 6 subjects per group sitting far apart. The major finding was the differential effect of the spatial variables on males and females for accuracy of perception of some aspects of the environment; for males, number of people in the group was the critical factor, for females density was the critical factor. Other results indicated that all subjects, regardless of sex, felt less comfortable in large groups than in small ones but that density influenced the judgment of how many people could fit comfortably in the room. There was no significant effect of the spatial variables on memory. One implication of this study is that future research on crowding should concentrate more on interactive effects rather than single factors.

Crowding↗
PubMed2002

Voluntary alcohol drinking & caloric intake in rats exposed to crowding stress.

BACKGROUND & OBJECTIVES: Alcohol intake in animals is regulated in much the same way as intake of food. The effect of alcohol on feeding behaviour is not well documented. The objective of this study was to test whether alcohol was ingested as a source of calories after crowding stress in rats. METHODS: Male albino rats were exposed to crowding stress continuously for two weeks and the effect of stress on the body weight, food intake, voluntary alcohol consumption and caloric intake in terms of food and alcohol was studied. RESULTS: A significant decrease in the body weight was seen after one (P < 0.05), 7 and 14 days (P < 0.01) of stress compared to controls. Food intake decreased significantly (P < 0.01) after one day of stress and there was recovery after 7 days stress. Absolute alcohol intake (g/kg body weight) increased significantly (P < 0.001) after one day of stress. Prolonged stress for two weeks significantly (P < 0.01) increased the alcohol consumption. Total caloric intake in stressed rats decreased significantly (P < 0.001) after acute stress. After 14 days, stressed rats showed significant (P < 0.001) increase in total caloric intake compared to day one. INTERPRETATION & CONCLUSION: Crowding stress decreased the body weight gain throughout the period of stress. Chronic stress for two weeks increased the voluntary alcohol consumption and total caloric intake. Food intake alone seemed insufficient to provide the extra demand of energy due to prolonged stress and hence, the rats may be drinking increasing amounts of alcohol (when provided) to supply the extra energy required to combat stress.

Alcohol Drinking↗
PubMed2005

Evolutionary change in parasitoid resistance under crowded conditions in Drosophila melanogaster.

Patterns of investment of limiting resources in such processes as competing for food and defense against natural enemies are shaped by trade-offs and constraints. In Drosophila melanogaster artificial selection for increased resistance to parasitoids results in a correlated decrease in larval competitive ability. Here we ask whether selection for competitive ability leads to a correlated reduction in parasitoid resistance. Replicated lines of D. melanogaster were maintained under crowded or uncrowded conditions for eight generations. As expected, the crowded lines evolved higher competitive ability (when tested against a common strain of fly). But instead of parasitoid resistance decreasing, we found a significant increase, and that this was associated with elevated densities of haemocytes in second-instar larvae. To understand these results we measured a variety of life-history traits in the two sets of lines. We find evidence that directly and indirectly selected changes in competitive ability are due to different mechanisms. We also ask why crowded conditions should select for increased resistance to parasitism, and conclude that it is unlikely to be due to correlated selection for resistance to other natural enemies, but might be due to correlated selection for better wound responses.

Animals↗
PubMed1988

Crowding and alcohol abuse as risk factors for tuberculosis in the Mamre population. Results of a case-control study.

As part of a community health programme, a population-based case-control study was undertaken to determine whether crowding and alcohol are risk factors for tuberculosis in Mamre. Forty notified cases of tuberculosis were compared with 84 randomly selected controls. Cases and controls were group-matched for age and sex. Seventy-six per cent of dwellings had a housing density ratio greater than 100%. There was no association between crowding and tuberculosis, but cases lived in houses that were significantly older than those of controls (odds ratio, 4,8, 95% confidence interval 1,5-15,6). There was an association between alcohol problems in the household and tuberculosis (odds ratio adjusted for employment status 2,2, 95% confidence interval 1,3-3,8). Further studies using refined methods are needed to evaluate the role of crowding in tuberculosis. The need for alcohol intervention campaigns in conjunction with tuberculosis control programmes directed at high-risk groups should be considered.

Adolescent↗
PubMed1978

The effects of crowding stress on the pancreatic islets morphology in golden hamsters.

Behavior and the pancreatic islets morphology of golden hamsters exposed for different periods (24 h, 15 and 30 d) to crowding stress were investigated. The crowding induced an intensive turmoil and enhanced irritability and aggressiveness, particularly among the female specimens. Within a week, a rank hierarchy seemed to establish and therefore, later the fighting incidence was more reduced. Marked morphological alterations were recorded in the endocrine pancreas, affecting in various degrees all cell types, but especially the insulin-producing cells. The B-cells showed increased sizes, higher incidence of mitotic divisions, a drastical reduction of secretory granules amounts, enlargement of GOLGI complexes, mitochondria swelling and extension of the ergastoplasm. On the other hand, after 30 d, part of these cells displayed pycnotic nuclei, large cytoplasmic vacuoles and increased number of lasosomes and lipid inclusions. Due to the B-cell hyperplasia, the relative number of both A1- and A2-cells per islet occurred diminished and their typical localization modified. The islets of 15 and 30 d crowded specimens showed enlarged sinusoids and clear peri-insular spaces. The above morphological modifications, which suggest as a whole the global stimulation of gland secretory activity, are presented in relation with other authors findings. The presumably involvements of adrenal-cortex and -medulla hormones in the mediation of stress-induced glycemic and pancreatic alterations are discussed.

Animals↗
PubMed1979

Combinative effects of hexachlorobenzene and crowding on rat adrenal cell mitochondria.

The effects of social stress (crowding) on hexachlorobenzene (HCB) toxicity in male rats was evaluated by a morphometrical analysis of adrenal cortex mitochondria. The social stress was produced by transferring singly-housed rats from cages of ample size (1000 cm2 floor space) into small cages (100 cm2 floor space) each containing four rats. Differences in cage design as well as size may have contributed to the overall stress experienced by the rats. The food of the treated rats was supplemented with 250 ppm HCB. Structural changes in mitochondrial volume, surface area, or cristae area were not significant in HCB-treated or in crowded animals when compared with those of the controls. However, increases in mitochondrial volume and diameter were significant in those animals simultaneously challenged by HCB and crowding. The results strongly suggest that even a relatively mild social stress may adversely affect the ability of an animal to resist the effects of some exogenous chemicals.

Adrenal Cortex↗
PubMed1993

Crowding--a risk factor for perinatal mortality?

Crowding is known to be associated with an increased risk of infant and child morbidity and mortality particularly due to infections. We examined the association of crowding with perinatal mortality. Our results indicated a paradoxical relationship with the least crowded households showing the highest perinatal mortality (7.7% as compared to 4.7%). However, further analysis indicated that the observed paradoxical relationship is a spurious one, largely explained by the confounding effect of gravidity.

Cross-Sectional Studies↗
PubMedDate not supplied

Macromolecular crowding in biological systems: hydrodynamics and NMR methods.

Most biologically relevant environments involve highly concentrated macromolecular solutions and most biological processes involve macromolecules that diffuse and interact with other macromolecules. Macromolecular crowding is a general phenomenon that strongly affects the transport properties of macromolecules (rotational and translational diffusion) as well as the position of their equilibria. NMR methods can provide information on molecular interactions, as well as on translational and rotational diffusion. In fact, rotational diffusion, through its determinant role in NMR relaxation, places a practical limit on the systems that can be studied by NMR. While in dilute solutions of non-aggregating macromolecules this limit is set by macromolecular size, in crowded solutions excluded volume effects can have a strong effect on the observed diffusion rates. Hydrodynamic theory offers some insight into the magnitude of crowding effects on NMR observable parameters.

DNA↗
PubMedDate not supplied

Large changes in cytoplasmic biopolymer concentration with osmolality indicate that macromolecular crowding may regulate protein-DNA interactions and growth rate in osmotically stressed Escherichia coli K-12.

From determination of amounts and concentrations of biopolymers and solutes in the cytoplasm of Escherichia coli, we are obtaining information needed to assess the effect of macromolecular crowding on cytoplasmic properties and processes of osmotically stressed bacteria. We observe that growth rate, and the amount of cytoplasmic water decrease and cytoplasmic concentrations of biopolymers and K+, increase with increasing osmolality, even for cells grown in the presence of osmoprotectants like glycine betaine. We observe general correlations between the amount of cytoplasmic water, growth rate and cytoplasmic K+ concentration in osmotically stressed cells grown both with and without osmoprotectants. To explain these correlations, we propose that crowding increases with increasing growth osmolality, which in turn buffers the binding of proteins to nucleic acids against changes in cytoplasmic K+ concentration and (by affecting biopolymer diffusion rates and/or assembly equilibria) is a determinant of growth rate of osmotically stressed cells. Changes in biopolymer concentration and crowding may also explain the increase of the activity coefficient of cytoplasmic water with increasing osmolality of growth in E. coli.

Betaine↗
PubMedDate not supplied

Effect of molecular crowding on self-association of phosphorylase kinase and its interaction with phosphorylase b and glycogen.

Self-association of phosphorylase kinase (PhK) and its interaction with glycogen (M=5500 kDa) and phosphorylase b (Phb) has been studied using analytical ultracentrifugation and turbidimetry under the conditions of molecular crowding arising from the presence of high concentrations of osmolytes. In accordance with the predictions of the molecular crowding theory, trimethylamine N-oxide (TMAO) and betaine greatly favor self-association of PhK induced by Mg2+ and Ca2+ and PhK interaction with glycogen. In contrast, proline suppresses these processes, probably, due to its specific interaction with PhK. All osmolytes tested prevented the complex formation between PhK and its physiological substrate, Phb. The specific interactions of PhK and Phb with glycogen, in the living cell, presumably is a factor allowing the negative effect of crowding on the recognition of Phb by PhK to be overcome.

Animals↗
PubMedDate not supplied

The effect of macromolecular crowding on protein aggregation and amyloid fibril formation.

Macromolecular crowding is expected to have several significant effects on protein aggregation; the major effects will be those due to excluded volume and increased viscosity. In this report we summarize data demonstrating that macromolecular crowding may lead to a dramatic acceleration in the rate of protein aggregation and formation of amyloid fibrils, using the protein alpha-synuclein. The aggregation of alpha-synuclein has been implicated as a critical factor in development of Parkinson's disease. Various types of polymers, from neutral polyethylene glycols and polysaccharides (Ficolls, dextrans) to inert proteins, are shown to accelerate alpha-synuclein fibrillation. The stimulation of fibrillation increases with increasing length of polymer, as well as increasing polymer concentration. At lower polymer concentrations (typically up to approximately 100 mg/ml) the major effect is ascribed to excluded volume, whereas at higher polymer concentrations evidence of opposing viscosity effects become apparent. Pesticides and metals, which are linked to increased risk of Parkinson's disease by epidemiological studies, are shown to accelerate alpha-synuclein fibrillation under conditions of molecular crowding.

Amyloid↗
PubMedDate not supplied

Studies of effects of macromolecular crowding and confinement on protein folding and protein stability.

In cells, proteins execute specific tasks in crowded environments; these environments influence their stability and dynamics. Similarly, for an enzyme molecule encapsulated in an inorganic cavity as in biosensors or biocatalysts, confinement or excluded volume plays an important role in its stability and dynamics. In this article we present results of our experimental and theoretical investigations of the confinement and macromolecular crowding effects on protein. On the experimental side we study the stability of encapsulated cytochrome c against unfolding induced by the presence of denaturants, such as urea. Results show that, as the pore size in which protein is trapped is reduced, protein shows higher stability against denaturant-induced unfolding. On the theoretical side, after reviewing our previous study of the confinement effects on the equilibrium and dynamic properties of protein using a minimalist (two-dimensional lattice, Monte Carlo, Brownian dynamics) model, we have extended the model so that the effects of macromolecular crowding on such properties can be studied. Our simulations show that both folding and unfolding times increase with the number of crowders in solution, however, the equilibrium constant is affected such that the equilibrium is shifted towards the folded state. Furthermore, our results show that, for a fixed number of crowders as the size of crowder (or excluded volume) increases, the average size of protein at equilibrium decreases.

Animals↗
PubMed1997

Rhesus monkey behaviour under diverse population densities: coping with long-term crowding

A popular view is that high population density promotes behavioural pathology, particularly increased aggression. In contrast, according to a coping model, some primates have behavioural mechanisms (e.g. formal displays, reconciliation and grooming) that regulate social tensions and control the negative consequences of crowding. Seven captive rhesus monkey groups, Macaca mulattawere observed over a wide range of population densities where high-density groups were over 2000 times more crowded than low-density free-ranging groups. As density increased, male rhesus monkeys increased grooming and huddling but did not increase rates of aggression. Females increased all categories of behaviour examined (heavy aggression, mild aggression, formal bared-teeth displays, grooming and huddling), but the increases were not distributed uniformly to all classes of partners. Females increased only grooming, huddling and appeasement displays to males, increased only aggression and huddling with kin and increased all categories of behaviour to non-kin adult females. There were no differences in the percentage of aggressive conflicts reconciled across density conditions. Increased density had different effects on particular relationships. Relationships between females and males were characterized by a coping pattern in which animals modified their behaviour in ways that may decrease aggression under crowded conditions. Female relationships with kin and non-kin were characterized by increases in both aggression and friendly interactions as density increased. The different patterns of response to higher density may reflect different strategies depending on the strength and stability of relationships and the potential consequences if certain relationships are disrupted.1997The Association for the Study of Animal Behaviour

Journal Article↗
PubMed1996

Epidemiology of childhood IDDM in Northern Ireland 1989-1994: low incidence in areas with highest population density and most household crowding. Northern Ireland Diabetes Study Group.

During the period 1989-1994, 462 cases of insulin-dependent diabetes mellitus were registered among children from Northern Ireland aged under 15 years. The estimated completeness of the register was 98.8% (95% confidence interval (CI) 97.7%, 99.9%). A standardised rate of 19.6 (95% CI 17.8, 21.4) per 100 000 person years was obtained, placing Northern Ireland near the top of the range of published incidence in the United Kingdom, with a rate close to that reported for Scotland. In an analysis based on 217 postcode sectors, areas with a high population density and the most material deprivation were observed to have the lowest incidence rates. After inclusion of population density in a Poisson regression analysis, the component of deprivation which was found to be most significant was household crowding. Relative to children living in areas of low population density, there was a reduced risk for children in medium (relative incidence 0.85 (95% confidence limits CI 0.67, 1.09)) and high (0.62 (95% CI 0.48,0.80)) population density areas. Similarly, relative to children living in areas with low levels of household crowding, there was a reduced risk for children in medium (relative incidence 0.73 (95% CI 0.58,0.93)) and high (0.67 (95% CI 0.53, 0.83)) levels of household crowding. Tests for space-time clustering at diagnosis and at birth were negative. A possible explanation for the differences in incidence rate observed in this study is that exposure to infections very early in childhood is a protective factor. Later infections may act as either initiators or promoters of diabetes, but the absence of space-time clustering suggests that no single specific infectious agent is responsible.

Adolescent↗
PubMed1998

Long-term development in the mandible and incisor crowding with and without an orthodontic stabilising appliance.

In children with dentoalveolar Class II malocclusion with proclined upper incisors treated with extraction of the maxillary first premolars and appliance in the upper jaw only has been reported to increase the lower arch crowding when compared with children with untreated normal occlusion. Stabilising orthodontic appliances might therefore be useful in the lower jaw. A comparison was made of Class II: 1 malocclusion with extraction in the upper arch in 35 individuals in whom a fixed orthodontic appliance was used in the upper arch only and 26 individuals with fixed appliances in both jaws. The mean age at the start of treatment was 12.9 and 12.8 years, respectively. Treatment effects and post-retention changes up to 4 to 5 years out of retention at the age of 20 to 22 years were evaluated from lateral head films and plaster casts. During treatment the orthodontic appliance in the lower arch relieved crowding. The available lower anterior space increased from -0.6 to +0.2 mm, compared, to a decrease from -0.4 to -1.3 mm in the group without mandibular appliances. After 4 to 5 years out of retention the lower arch available space had decreased in both groups, to -1.4 mm in the group where orthodontic appliances had been used in both jaws and to -2.5 mm in the group without an orthodontic appliance in the lower jaw. This difference was significant. But the subjective ranking of the amount of crowding in the lower jaw models showed no significant difference between the 2 groups at the age of 20 to 22 years.

Adolescent↗