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PubMed1990

[Two cases of crowding with disharmony between the upper and lower jaws].

Since the malocclusion involved with a disharmony between the upper and lower jaws is generally treated with growth stimulation and inhibition to correct the disharmony, orthodontic treatment for this type of malocclusion is usually started at an early age. On the other hand, the case of crowding which has no such problem is caused by so called arch length discrepancy; discrepancy between teeth and jaw sizes. This type of maloccusion, therefore, is usually treated with extraction of teeth and in most of these cases treatment is started after the permanent dentition is established and growth and development of the maxilla is fairly well completed. Actually, however, case of crowding often have skeletal disharmony as a potential problem, in which cases the orthopedic approach is thought to be better if started rather early. This is because the orthodontic approach alone is not enough to solve skeletal problems, which problems are better handled before the teeth are moved. This procedure can prevent excessive tooth movement. The two cases reported here with crowding as the chief complaint were treated by the early orthopedic approach for potential skeletal problems prior to orthodontic correction. The results indicate the effectiveness of this procedure.

Child↗
PubMed1990

"Macromolecular crowding": thermodynamic consequences for protein-protein interactions within the T4 DNA replication complex.

In vitro biochemical assays are typically performed using very dilute solutions of macromolecular components. On the other hand, total intracellular concentrations of macromolecular solutes are very high, resulting in an in vivo environment that is significantly "volume-occupied." In vitro studies with the DNA replication proteins of bacteriophage T4 have revealed anomalously weak binding of T4 gene 45 protein to the rest of the replication complex. We have used inert macromolecular solutes to mimic typical intracellular solution conditions of high volume occupancy to investigate the effects of "macromolecular crowding" on the binding equilibria involved in the assembly of the T4 polymerase accessory proteins complex. The same approach was also used to study the assembly of this complex with T4 DNA polymerase (gene 43 protein) and T4 single-stranded DNA binding protein (gene 32 protein) to form the five protein "holoenzyme". We find that the apparent association constant (Ka) of gene 45 for gene 44/62 proteins in forming both the accessory protein complex and the holoenzyme increases markedly (from approximately 7 x 10(6) to approximately 3.5 x 10(8) M-1) as a consequence of adding polymers such as polyethylene glycol and dextran. Although the processivity of the polymerase alone is not directly effected by the addition of such polymers to the solution, macromolecular crowding does significantly stabilize the holoenzyme and thus indirectly increases the observed processivity of the holoenzyme complex. The use of macromolecular crowding to increase the stability of multienzyme complexes in general is discussed, as is the relevance of these results to DNA replication in vivo.

Adenosine Triphosphatases↗
PubMed2001

Effects of short-term crowding stress on the gilthead seabream (Sparus aurata L) innate immune response.

Gilthead seabream specimens were subjected to an intense short-term crowding stress of 100 kg m(-3) for 2 h. After 0, 1, 2, 3 and 4 days, blood glucose and serum cortisol levels, serum complement activity, phagocytic and respiratory burst activities of head-kidney leucocytes, and the percentage of monocyte/ macrophages and granulocytes in head-kidney and circulating blood were determined. An immediate effect of the stress was a depression in complement and phagocytic activities, both of which recovered after 3 or 2 days, respectively, while respiratory burst remained unaffected. The depression of phagocytosis in head-kidney leucocytes seemed to correlate with stress-induced migration of active cells from the organ to circulating blood. The present results point to the importance of minimising intense short-term crowding stress in order to reduce possible states of immunodepression in farmed fish.

Animals↗
PubMed1996

A comparison of operating room crowding between open and laparoscopic operations.

BACKGROUND: The clutter of equipment and lines in today's operating room (O.R.) is increasing. Endoscopic surgical procedures are particularly afflicted by this problem because they require additional equipment. Increasing O.R. crowding may present unnecessary hazards to traffic and adversely affect the performance of the surgical team. The purpose of this study is to provide a quantitative summary of the furniture, equipment, cables, and tubes present during open and laparoscopic operations. METHODS: We prospectively studied an unselected series of general surgical open (OP, n = 10) and laparoscopic (LAP, n = 10) operations performed at a major university teaching hospital. We recorded the location of all furniture and equipment as well as the source, course, and destination of all cables and tubes in the O.R. Cables and tubes touching the surgeon or the assistant were particularly noted. Results are expressed as median values for each group. RESULTS: The percent of O.R. space occupied increased from OP = 36% to LAP = 41% (p < 0.002). The median number of cables and tubes present increased from OP = 27 to LAP = 34 (p < 0.0002), with the number of these lines touching a member of the surgical team increasing from OP = 2 to LAP = 6 (p < 0.0003). CONCLUSIONS: We conclude that there is a significant trend toward increasing O.R. crowding during laparoscopic surgery. Innovative designs will be needed to reduce clutter in the O.R. of the future.

Crowding↗
PubMed1994

Pituitary-adrenocortical responsiveness to histaminergic stimulation during social stress of crowding in rats.

Social stress of crowding for 3, 7, 14 and 21 days drastically reduces the serum corticosterone response to intracerebroventricular administration of dimaprit, a histamine H2-receptor agonist, moderately diminishes the response to pyridylethylamine, an H1-receptor agonist, and does not change significantly the corticosterone response to histamine. These results suggest that social stress of crowding considerably desensitizes central histamine H2-receptors involved in stimulation of the hypothalamic-pituitary-adrenal axis.

Animals↗
PubMed2006

Finding a face in the crowd: testing the anger superiority effect in Asperger Syndrome.

Social threat captures attention and is processed rapidly and efficiently, with many lines of research showing involvement of the amygdala. Visual search paradigms looking at social threat have shown angry faces 'pop-out' in a crowd, compared to happy faces. Autism and Asperger Syndrome (AS) are neurodevelopmental conditions characterised by social deficits, abnormal face processing, and amygdala dysfunction. We tested adults with high-functioning autism (HFA) and AS using a facial visual search paradigm with schematic neutral and emotional faces. We found, contrary to predictions, that people with HFA/AS performed similarly to controls in many conditions. However, the effect was reduced in the HFA/AS group when using widely varying crowd sizes and when faces were inverted, suggesting a difference in face-processing style may be evident even with simple schematic faces. We conclude there are intact threat detection mechanisms in AS, under simple and predictable conditions, but that like other face-perception tasks, the visual search of threat faces task reveals atypical face-processing in HFA/AS.

Adult↗
PubMed2006

Dwellings, crowding, and tuberculosis in Montreal.

The association of tuberculosis (TB) with poverty has long been recognized, yet it may reflect not only characteristics of poor individuals, but also housing and neighborhood features which promote airborne spread. We sought to determine whether dwelling and building features, residential density and crowding are independently associated with TB occurrence in a low-incidence setting. We used residential addresses to geocode active TB cases reported in Montreal in 1996-2000. These "case dwellings" were linked to the municipal dwelling geodatabase from 2000, and to Canadian census data from 1996. We compared them with randomly selected Montreal dwellings ("controls," in a 1:10 ratio), using the same data sources. From multivariate logistic regression, the 595 case dwellings were more likely than the 5950 control dwellings to be in buildings >5 stories tall (adjusted odds ratios [OR] 1.6; 95% CI: 1.0-2.5), constructed since 1970 (adjusted OR 2.5; 1.8-3.6), in the lowest quartile for resale valuation (adjusted OR 1.3; 1.0-1.6), and on blocks where lot coverage exceeded the median value (adjusted OR 1.3; 1.0-1.6). Case dwellings were also more often found in census tracts with more persons per room, and a higher proportion of inhabitants who had arrived in Canada within the last 5 years. We conclude that dwelling and building features-notably dwellings in taller and new buildings, with lower resale value, and dwellings on blocks with high residential density-as well as crowding, were associated with TB occurrence, after adjustment for sociodemographic factors.

Crowding↗
PubMed2004

The effect of emergency department crowding on paramedic ambulance availability.

STUDY OBJECTIVE: We determine the effect of emergency department (ED) crowding on paramedic ambulance availability. METHODS: This was a prospective longitudinal study from April 2001 through March 2002 in Los Angeles, CA. All incidents in which a Los Angeles Fire Department ambulance was out of service for more than 15 minutes while waiting to transfer a patient because of the lack of open ED beds were captured and analyzed. Data included the total time each ambulance was out of service and the hospital where paramedics were waiting for an open gurney. Analysis was performed to determine weekly and seasonal variations and preponderance at various hospitals. RESULTS: There were a total of 21,240 incidents in which ambulances were out of service while waiting to transfer their patients to an open ED gurney, which accounted for 1 of every 8 transports. Of these, 8.4% were in excess of 1 hour. The median waiting time per incident was 27 minutes, with an interquartile range of 20 to 40. There was a statistically significant difference in the monthly number of out-of-service incidents during the study (P<.0001), with the highest levels during the winter (January through March). CONCLUSION: ED crowding has resulted in delays for paramedics waiting to transfer patients. This decrease in ambulance availability may have a significant effect on emergency medical services systems' abilities to provide timely response.

Allied Health Personnel↗
PubMed1998

Crowd physiology: the 'penguin effect'.

The effects of heat retention on an individual in a crowd situation (the 'penguin effect') is introduced and described, with implications for the emergency services and the potential casualties themselves discussed. Management of anyone who collapses in the core of a crowd should involve much more than first-aid treatment for fainting. Some people may die from the effect.

Crowding↗
PubMed1975

An experimental study of crowding: effects of room size, intrusion, and goal blocking on nonverbal behavior, self-disclosure, and self-reported stress.

This study hypothesized that stress in high room density, or crowding, depends on interpersonal disturbances such as intrusion and goal blocking. High room density was expected to intensify individual reactions to these disturbances. In a 2 X 2 X 2 design, groups of six male college students containing three subjects and three confederates were placed in a large or small room. Subjects and confederates interacted in pairs; confederates introduced intrusion by leaning forward, touching subjects, and attempting 80% eye contact as confederates talked. Goal blocking involved inattention and interruptions as subjects talked. Interactions were videotaped through two-way mirrors to record nonverbal behaviors associated with affiliation and stress. Subjects also completed self-report measures of stress and self-disclosure. Intrusion led to initial discomfort that decreased with time, and lower levels of facial regard. Goal blocking produced self-reported irritation that increased with time, and lower levels of facial regard, gesturing, and positive head nodding. Contrary to predictions, stress responses to intrusion and goal blocking were not intensified by high room density. Lower levels of affiliative behavior were viewed as coping responses to interpersonal disturbances--subjects apparently coped successfully with intrusion, but not with goal blocking. Results are interpreted in terms of a sequential, interpersonal model of crowding.

Adolescent↗
PubMed2003

Intervention to decrease emergency department crowding: does it have an effect on return visits and hospital readmissions?

STUDY OBJECTIVES: We evaluate the effect of a multifaceted intervention to decrease emergency department crowding on the incidence of return visits to the ED or a hospital ward. The intervention included increased emergency physician coverage, the designation of physician coordinators, and new hospital policies regarding laboratory, consultation, and admission procedures. METHODS: The incidence of return visits within 7 days of discharge was estimated in samples from 2 populations (ie, patients discharged from the ED and patients discharged from the hospital) and during a 12-month period before and a 12-month period after the implementation of the intervention. Return visits were categorized into the following groups: (1) scheduled or not and (2) related or not to initial visit. Logistic regression was used in subsamples to assess the effect of the intervention while controlling for potential confounders. By using information from the provincial medical services database, variation between the periods before and after implementation of the intervention in the incidence of return visits to any ED was compared between the study hospital and 2 external control hospitals. RESULTS: No difference was found in the incidence of return visits between the periods before and after implementation of the intervention, either for patients discharged from the ED (all returns: 11.0% versus 12.4%, 95% confidence interval on difference [CID] -1.5% to 4.3%; unscheduled-related returns: 6.5% versus 5.8%, 95% CID -2.8% to 1.6%) or the hospital (all returns: 6.8% versus 6.6%, 95% CID -2.5% to 2.1%; unscheduled-related returns: 4.2% versus 4.0%, 95% CID -2.0% to 1.7%). This lack of effect remained even after controlling for potential confounders. Variation between the periods before and after implementation of the intervention in the incidence of return to any ED was similar in the 3 hospitals examined. CONCLUSION: Our successful hospital intervention to decrease crowding reduced the mean length of stay for patients discharged from the ED from 13.8 to 5.9 hours, without resulting in increased return visits to the ED or hospital readmission.

Aged↗
PubMed1991

Personal space and density as factors in task performance and feeling of crowding.

The study was an investigation of the effects of density and personal space on simple and complex task performance and on feelings of crowding on 60 female Hindu students in India. A 2 x 2 design was used. Density was manipulated by varying the number of subjects in a fixed room space (social density), and the stop-distance technique was used to measure personal space. Results revealed that complex task performance was adversely affected by a high-density condition and by the personal space of the subjects, leading to a significant interaction effect of the two variables, but no significant main or interaction effect was found for the simple task performance. The subjects with "far" personal space under the high-density condition evaluated the environment of the experimental room as most crowded, more than any other subject did.

Adolescent↗
PubMed2004

Crowding as a risk factor of meningococcal disease in Danish preschool children: a nationwide population-based case-control study.

Meningococcal disease (MD) remains an important health problem. Crowding has been suggested to be a risk factor for MD in children, but the evidence is relatively sparse. We performed a nationwide nested case-control study comprising 1222 children with MD and 24,549 population controls. We identified MD cases younger than 6 y in the Danish National Hospital Discharge Registry from 1980 to 1999, and obtained information on household density as a measure of crowding, per capita income and other potential confounders through The Danish Civil Registration System and social registries. The risk of MD associated with household density was estimated by conditional logistic regression for children less than 1 y of age (infants) and children aged 1 to 5 y, respectively. The risk of MD increased with increasing household density. In both age groups, the crude OR was 1.8 (95% confidence interval [CI]: 1.4-2.3) at a density of less than 20 m2 per person compared with the reference of more than 50 m2 per person. The adjusted OR for MD was 1.5 (95% CI: 1.1-1.9) for infants, and 1.5 (95% CI: 1.1-2.0) for children older than 1 y. Household density appears to be a risk factor of MD in preschool children.

Age Distribution↗
PubMed1997

Impact of tuberculosis control measures and crowding on the incidence of tuberculous infection in Maryland prisons.

Our aim was to determine the incidence of tuberculin skin test (TST) conversion in the Maryland state correctional system. We conducted a historical longitudinal cohort study. A sample of 1,289 inmates, incarcerated in 16 of 23 prisons, who had a negative TST and a second test within 24 months was selected. The incidence of recent conversion was 6.3 per 100 person-years. Risk factors for conversion included high prison-population density (relative risk [RR] = 2.4; 95% confidence interval [CI], 1.5-3.8) and incarceration in a higher-security institution (RR = 2.4; 95% CI, 1.4-4.3). Incarceration in an institution with higher levels of isoniazid prophylaxis (> 65% of TST positives) reduced the risk of infection by 50% (RR = 0.5; 95% CI, 0.3-0.7). Crowding was strongly correlated with risk of conversion (r = 0.83; P < .001), while rates of isoniazid prophylaxis initiation were inversely correlated with risk of infection (r = -0.82; P < .001). In stepwise regression, higher prison-population density was the strongest predictor of increased infection. In a final model, inclusion of the rate of isoniazid prophylaxis initiation reduced the risk associated with crowding (RR = 1.4; P = .4). Annual screening programs for prisons can identify recent conversions that may not otherwise be detected.

Adult↗
PubMedDate not supplied

Modeling crowd and trained leader behavior during building evacuation.

This article considers animating evacuation in complex buildings by crowds who might not know the structure's connectivity, or who find routes accidentally blocked. It takes into account simulated crowd behavior under two conditions: where agents communicate building route knowledge, and where agents take different roles such as trained personnel, leaders, and followers.

Computer Graphics↗
PubMedDate not supplied

Simultaneous effect of initial weight, initial crowding, temperature and O2 concentration on the nutritional use of food by rainbow trout (Oncorhynchus mykiss).

The simultaneous effects of initial weight, initial crowding, temperature and O2 concentration on the following ratios: relative growth rate percent (RGRP), feed efficiency (FE), protein efficiency ratio (PER) and protein productive value (PPV) were studied in the rainbow trout. Multivariant equations were obtained for each of the mentioned indices. The joint effects of these factors were evidenced by means of a multiple correlation analysis. The influence of temperature and, to a lesser extent, of crowding, and O2 concentration on the nutritional use of food by the trout was demonstrated, their fundamental dependence on factors extrinsic to the animal being underlined. The non proportional changes in PER and PPV as temperature rises revealed that an increasing part of the ingested aminoacids were used for synthesis of fat, non for proteins edification.

Animal Feed↗
PubMed1984

Developmental physiology of cestodes: characterization of putative crowding factors in Hymenolepis diminuta.

It was shown previously that worm-conditioned saline (WCS) prepared from crowded 10-day-old H. diminuta inhibited the incorporation of 3H-thymidine into DNA in the anterior regions of uncrowded worms and that the inhibition was partially accounted for by succinate and acetate excreted by the worms. The present study describes further characterization of the active components of WCS. An ultrafiltrate was fully as potent as untreated WCS, indicating that all detectable inhibitory components were less than about 500 daltons in molecular mass. Inhibitory factors in WCS were stable to heat (80 C for 30 min), cold (4 C for 48 hr), drying and reconstitution, alkaline pH (11 to 12 for 3 hr), and ethanolic extraction. Active compounds were probably not lipoidal in nature. Although the acidic ethanol extract of WCS was inhibitory, no activity was observed in fractions of WCS that contained basic, acidic and neutral amino acids. Amino compounds in the WCS were further investigated. Twenty-four amino acids were identified, 3 of which (phosphoserine, 1-methylhistidine, and 3-methylhistidine) have not been reported previously for H. diminuta. On a molar basis, alanine accounted for 40-50% of the amino acids released. The amino sugar, D-glucosaminic acid, was found in the WCS and also has not been heretofore reported from H. diminuta or any other cestode. In concentrations comparable to those in the WCS, D-glucosaminic acid inhibited incorporation of 3H-thymidine into the DNA of the tapeworms by 25-35%, suggesting that D-glucosaminic acid may be one of the crowding factors.

Alanine↗