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PubMed2006

Hyperchromatic crowded groups in cervical cytology--differing appearances and interpretations in conventional and ThinPrep preparations: a study from the College of American Pathologists Interlaboratory Comparison Program in Cervicovaginal Cytology.

CONTEXT: The practice of gynecologic cytology requires that high-grade squamous intraepithelial lesion (HSIL) be precisely recognized. In this regard, hyperchromatic crowded groups are known to be difficult to classify in conventional gynecologic cytology, but whether this is true in ThinPrep specimens is uncertain. OBJECTIVE: To assess whether hyperchromatic crowded groups of cells in challenging HSIL cases are a problem in ThinPrep preparations, and whether these groups differ in appearance from those of conventional smears. DESIGN: Sixteen images were taken from both conventional smears and ThinPrep slides that had a reference diagnosis of HSIL in the College of American Pathologists Interlaboratory Comparison Program in Cervicovaginal Cytology, but had performed poorly on subsequent participants' reviews. These 32 representative images were of hyperchromatic crowded groups and were classified by 20 Cytopathology Resource Committee members (17 pathologists and 3 cytotechnologists), who were masked to the reference diagnosis. A consensus classification was derived using the majority opinion of the individual reviewers. Finally, 5 cytologic features were assessed for those images that were interpreted as abnormal by the consensus classification. RESULTS: None of the 32 images was uniformly interpreted as either benign, squamous lesion, or glandular lesion on individual review. Only 27% of individual interpretations of conventional smear images and 15% of ThinPrep images were interpreted as HSIL/squamous cell carcinoma (P < .001). Individual interpretations of ThinPrep images as glandular lesions (60%) were more often made than those of conventional smears (44%, P < .001). The consensus interpretation of ThinPrep images was glandular lesion in 75% of cases, whereas fewer than 50% of the consensus interpretations of conventional smear images were in this category. Conventional smear images were characterized by elongate nuclei (43%) and large nuclei (71%), whereas ThinPrep images more often showed rounded smooth edges (53%) and small nuclei (80%), and were recognized as a glandular lesion. CONCLUSIONS: Hyperchromatic crowded groups of cells are a source of difficulty in challenging HSIL cases for both conventional smears and ThinPrep specimens. In conventional smears, these groups are more likely to be labeled as a squamous lesion, owing to their elongate and large nuclei. In ThinPrep specimens, however, these groups are more likely to be labeled as glandular lesions, owing to their smooth contoured borders and small nuclei.

Carcinoma, Squamous Cell↗

PubMed2003

Enhancement of development of larval Anopheles arabiensis by proximity to flowering maize (Zea mays) in turbid water and when crowded.

To determine whether proximity to flowering maize enhances the development of larval anopheline mosquitoes breeding in turbid water and when crowded, we evaluated the development of larval Anopheles arabiensis under various conditions of turbidity, larval density, and proximity to pollen-shedding maize in simulated breeding puddles in a malaria-endemic site. In naturally formed puddles, water turbidity, as well as larval density, increased as the rainy season progressed. In sites remote from flowering maize, more pupae developed and the resulting adults were larger in relatively clear water than in turbid water, and larval crowding inhibited development. In close proximity to flowering maize, however, larval development was little affected by water turbidity and larval crowding. Larvae of this member of the African An. gambiae complex of mosquitoes develop readily in turbid water and when crowded, provided that their breeding sites are located where maize pollen is abundant.

Animals↗

PubMed2004

The effect of different lower third molar conditions on the re-crowding of lower anterior teeth in the absence of tight interproximal contacts one-year post orthodontic treatment: a pilot study.

The role of lower third molars in lower incisor crowding is a debatable topic. Some believe the presence or eruption of lower third molars is associated with the crowding of mandibular incisors, others negate such association. Thirty-two newly debonded orthodontic patients, with ages ranging from 14-19 years, were randomly selected. No retainers were used for the lower dental arch. Removal of tight interproximal contacts of the lower anterior teeth was created and maintained by periodic abrasive stripping every 2-3 months, if needed. The cases were followed up for one year. Orthopantomographs (OPGs) and study casts were taken at debonding (post-treatment) and at the end of the one year follow up (post retention). Statistical analysis of the lower third molar conditions--erupted, unerupted, or missing with or without sufficient space for their eruption--versus re-crowding of lower incisors was evaluated using Fisher's Exact Test. The results of this pilot study revealed there was no significant correlation between the different conditions of the lower third molars versus lower anterior re-crowding in the absence of tight interproximal incisal contacts; however, a larger sample size is needed to verify such findings.

Adolescent↗

PubMed1978

Application of analysis of crowding and spacing of the teeth.

Spacing or crowding of the teeth is measured and analyzed to assist in decisions regarding the maintenance of teeth in their existing positions or their movement to improved positions. Numerical guides always should incorporate a gray zone in which decisions cannot be made without additional information. In the stage of mixed dentition, estimates of the size of unerupted teeth are more accurate than estimates of future spacing or crowding because the perimeter of the arch does not diminish the same amount in all cases. Instead, it appears to be related to the amount of crowding in the mixed dentition. Determination of the amount of crowding or spacing must always be accompanied by consideration of molar, canine, and incisor relationships. In addition, the effect of the dentition on lip posture should also be evaluated.

Child↗

PubMed1982

Developmental physiology of cestodes. XVII. Some biological properties of putative "crowding factors" in Hymenolepis diminuta.

A "worm conditioned saline" (WCS) was prepared by incubation of 10-day-old Hymenolepis diminuta (Cestoda: Cyclophyllidea) from infections varying in population density (10, 50, 100 worms per host). Upon subsequent testing on 10-day-old worms from uncrowded (10 worms) infections, WCS prepared with worms from more crowded populations inhibited 3H-thymidine incorporation into DNA to a greater degree than did WCS prepared with worms from less crowded populations. WCS prepared with adult worms (20-30 days old) from crowded (50-worm) infections also inhibited DNA synthesis in 10-day-old cestodes from 10-worm infections. WCS from the anterior ends of adult worms was more inhibitory than WCS prepared with gravid proglottids. The time course of the inhibition was consistent with a G1 block in the cell cycle of the stem cells of the germinative area. The experiments lend support to the hypothesis that these cestodes secrete "crowding factors" that inhibit the growth of other H. diminuta in the same rat.

Acetates↗

PubMed1994

Masticatory function in normal and crowded occlusion using Hellman's dental stages.

As a consequence of this study, the following conclusions were obtained by means of an estimate of the interocclusal point number of the integrated value of the electromyographs, of the masticatory rhythm with 40 subjects in each group (the normal groups: IIA 10. IIIA 10, IIIC 10, IVA 10; the crowding groups: IIA 10, IIIA 10, III C 10, IVA 10). 1. From the view of the integrated value of the electromyographs. In the normal groups with a normal occlusion. TA% to the total active potentials turned out to be less in proportion to the advancement of the dental stages, while TP% remained as the same. M% should an increase, whose ratio turned out to be high enough to take TA's place. 2. In the crowding groups, in spite of the indication of TA's decrease, M's increase, a comparison with the normal groups' that even after the stage IIIC TA-M-type masticatory pattern had to be maintained. 3. Regarding the interocclusal point number, in IIIC, IVA, the total amount and number at the molar segments indicated a significantly smaller value in the crowding groups. 4. Concerned with the integrated value of the masticatory muscle, the most related factor to yield the characteristic masticatory pattern observed in the crowding groups could be considered the number of the interocclusal points, which proved that great importance should be paid to the maintenance of the well harmonized status of the upper and lower occlusion.

Case-Control Studies↗

PubMed1980

Crowded jewel fish show changes in dendritic spine density and spine morphology.

This study demonstrates that neuronal development can be adversely affected by short-term crowding. Compared with uncrowded siblings (15 fish/73-litre), juvenile jewel fish (15 fish/3.6-litre) crowded for 60 days exhibited 50-58% fewer dendritic spines and spines with narrower heads on pyriform interneurons in deep tectal strata. These findings indicate that crowded environments can produce aberrant neuronal development similar to that seen in socially deprived jewel fish.

Aggression↗

PubMed2006

Prediction of human crowd pressures.

Published data on accidents in human crowds that occurred over the past decade show that one of the fatal consequences of crowding was asphyxia, that is by crushing. Here a study was made of our ability to predict human crowd pressures at barriers and thereby be able to take preventive action before crushing causes injury. Utilizing the standard forward-backward autoregressive modeling techniques for spectral analysis of a measured signal, predictions of pressures generated by very high densities of pedestrians have been formulated. The study suggests that several minutes are available for corrective action to be taken to avoid an accident involving crushing of pedestrians.

Accident Prevention↗

PubMed2005

Effect of the acute crowding stress on the rat brown adipose tissue metabolic function.

Our previous results have shown that metabolic and thermal stressors influence interscapular brown adipose tissue (IBAT) metabolic activity by increasing oxygen consumption and, consequently, altering the toxic reactive oxygen species (ROS) production and the antioxidative system activity. Since there is not enough evidence about the effect of psychosocial stressors on these processes, we studied the effect of acute crowding stress on the IBAT and hypothalamic monoamine oxidase (MAO) activity as well as IBAT antioxidative enzymes, manganese (MnSOD), copper-zinc superoxide dismutase (CuZnSOD) and catalase (CAT), as the relevant indicators of IBAT metabolic alternations under the stress exposure and the returning of animals to control conditions. The results indicated that acute crowding stress did not change the hypothalamic and IBAT MAO activities, the generation of ROS and, consequently, the IBAT CuZnSOD and CAT activities. However, all three antioxidative enzymes were affected only after the recovery period. It seems that peripheral overheating of rats during acute crowding changes the stress nature, by becoming more thermal than psychosocial and by suppression the hypothalamic efferent pathways involved in the IBAT thermogenesis regulation. However, it seems that returning of the animals to the control conditions after the stress termination causes the reactivation of IBAT thermogenesis with tendency to normalise the body temperature.

Adipose Tissue, Brown↗

PubMed1979

The effects of short-term exposure to crowding stress on the pancreatic islets morphology and glycemia in mice.

Behavior, pancreatic islets morphology and plasma glucose levels of male mice exposed for 2, 4, 24 and 48 hours to crowding stress were investigated. The crowding induced an intense turmoil state associated with enhanced irritability and aggressiveness among the specimens of all experimental groups. Violent fights occurred especially in the first 4--6 hours, generally with the death of 1--2 individuals from each group. The changes recorded in the pancreatic islets affected first (2 hours) exclusively the insulin-producing cells, and in subsequent intervals they progressively expanded over all cell types. The changes occurred during the experiment in all islet cell types; however the B-cells showed by far the most pronounced alterations irrespective of the studied time interval. Most changes suggested the stimulation of the entire gland secretory activity, but particularly of B-cells, which was also proved by low glycemia values recorded at 3 of the 4 crowding time intervals. On the other hand, some alterations, occurring first at 24 hours, were regarded as signs of a moderate B-cells secretory hypoactivity; they may partly support the slight hyperglycemia obtained at this time interval. The significance of the above short-term observations in the induction of glycoregulation disturbances, diabetes included, as well as the presumably mediation role of adrenal-cortex and -medulla hormones under stress conditions are discussed and correlated with findings reported in literature.

Animals↗

PubMed1992

The effects of crowding on adults of Philophthalmus nocturnus grown in domestic chicks.

The effects of crowding on growth, reproduction, rate of recovery and site of infection of Philophthalmus nocturnus were investigated by infecting various groups of day-old chicks with 25, 50, 75, or 100 excysted metacercariae and examining them at 10 or 25 days post-infection. Considerable reduction in the body length and the size of the gonads was noticed in flukes grown under crowded conditions. Crowding also caused some change in the habitat of flukes, but had no effect on their rate of recovery. Very few flukes reached the ovigerous stage under overcrowded conditions and none reached the embryonated larval stage.

Animals↗

PubMed1999

Parental language and verbal responsiveness to children in crowded homes.

This article is a secondary data analysis of the University of Kansas Language Acquisition Project, which intensively studied, on a regular basis, parent and child language from age 6 months to 30 months. The association between residential density and parent-child speech was examined. Parents in crowded homes speak in less complex, sophisticated ways with their children compared with parents in uncrowded homes, and this association is mediated by parental responsiveness. Parents in more crowded homes are less verbally responsive to their children. This in turn accounts for their simpler, less sophisticated speech to their children. This mediational pathway is evident with statistical controls for socioeconomic status. This model may help explain prior findings showing a link between residential crowding and delayed cognitive development.

Child, Preschool↗

PubMed1982

The development of the mood-inhibiting effects of crowding during adolescence.

Prior research on the effects of crowding on human behavior has concentrated on aggression and negative affect. The present study centered on the possible inhibiting effects of crowding on the development of positive mood states. Males (n = 72) and females (n = 72) representing early, middle, and late adolescence were examined under conditions of high and low spatial density. Subjects were provided with positive mood-inducing stimuli or neutral stimuli during density conditions. Crowding produced neither positive nor negative moods on groups beyond young adolescence. Effectiveness of positive mood producing stimuli was inhibited for late adolescent males and females.

Adolescent↗

PubMed1992

Crowding effects of density and interpersonal distance.

In this study, Turkish teenagers were the subjects in an investigation of the effects of spatial and social variables on perceived crowding. In Study 1, male and female subjects were presented with diagrams that simulated social situations in which (a) distance between the subject and other persons, (b) number, or density, of subjects, (c) sex, and (d) friendship were systematically varied. Results indicated a significant crowding effect for interpersonal distance but not for density. In Study 2, data from Turkish college students showed that the lack of effect for density on crowding was stable. Friendship and sex of others had significant main and interaction effects.

Adolescent↗

PubMed1998

Serum composition of Aedes aegypti (Diptera: Culicidae) larvae and the production of an oviposition repellent are influenced by infection with the entomopathogenic digenean Plagiorchis elegans (Trematoda: Plagiorchiidae), starvation, and crowding.

Subjecting Aedes aegypti (L.) larvae to conditions that induced the production of oviposition repellency also reduced their wet and dry weights and the concentration of total serum carbohydrates, amino acids, and proteins. Thus, infection with metacercariae of the entomopathogenic digenean Plagiorchis elegans (Rudolphi), starvation for 7 d, or crowding for 2 d reduced larval dry weights by as much as 32, 20, and 23%, respectively, and wet weights by 20, 14, and 11%, respectively. Total serum carbohydrates declined by as much as 36, 21, and 29% for infected, starved, and crowded larvae, respectively, amino acids by 39, 48, and 44%, and protein concentrations by 72, 63, and 62%, respectively. Repellency dilution titers were correlated inversely with movement of the mouth parts and gut. Incubation of infected, starved, and crowded larvae in 0.01 g/liter glucose greatly reduced the level of repellency of their waters, whereas adding glucose to repellent waters had only minor effects. Results indicate that the induction of repellency is associated strongly with nutritional depletion effects.

Aedes↗

PubMed1981

Crowding in prison: the relationship between changes in housing mode and blood pressure.

The relationship between change in mode of housing and corresponding blood pressure (BP) change was investigated among 568 male prisoners as an analogue to animal studies which have shown that crowding elevates BP. The transfer from single occupancy cells to multiple occupancy dormitories was associated with a statistically significant mean increase in systolic blood pressure (SBP). In contrast, men who remained in single cells had little mean change in SBP over time. Inmates who were retransferred to cells after a short stay in dormitories experienced a mean decline in SBP, which suggests that crowding may be reversible in its early stages. SBP also decreased after continued stay in the dormitories, indicating that adaptation may occur. The implications of these findings for crowding theory and their contribution to an understanding of response to the prison environment are discussed.

Adult↗

PubMed1962

Prenatal influence on behavior of offspring of crowded mice.

Pregnant albino mice were subjected to stress by crowding. When the litters encountered unfamiliar stimuli, they were less active, they were slower to respond, and they defecated less than control mice. These differences persisted at 30 and 100 days of age, whether the mice were raised by a crowded or by an uncrowded mother, and in spite of starvation. One explanation may be that aberrant endocrine activity in the crowded, pregnant female impairs the development of fetal response systems.

Animals↗

PubMed1973

Crowding among hunter-gatherers: the Kung Bushmen.

Highly crowded living conditions exist among the !Kung Bushmen, hunter-gatherers who live on the edges of the Kalahari Desert in Botswana and South-West Africa. The !Kung appear to be crowded by choice, and biological indicators of stress are absent. Data indicate that residential crowding alone does not produce symptoms of pathological stress.

Adult↗