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PubMed2006

Comparison of the National Emergency Department Overcrowding Scale and the Emergency Department Work Index for quantifying emergency department crowding.

BACKGROUND: Emergency department (ED) crowding is just beginning to be quantified. The only two scales presently available are the National Emergency Department Overcrowding Scale (NEDOCS) and the Emergency Department Work Index (EDWIN). OBJECTIVES: To assess the value of the NEDOCS and the EDWIN in predicting overcrowding. The hypothesis of this study was that the NEDOCS and the EDWIN would be equally sensitive and specific for overcrowding. METHODS: The NEDOCS, the EDWIN, and an overcrowding measure (OV) were determined every two hours for a ten-day period in December 2004. The NEDOCS is a statistically derived calculation, and the EDWIN is a formula-based calculation. The overcrowding measure is a composite of physician and charge nurse expert opinion on the degree of overcrowding as measured on a 100-mm visual analogue scale (VAS). The primary outcome, overcrowding, was based on the dichotomized OV VAS score at the midpoint of 50 mm (> or =50, overcrowded; <50, not overcrowded). The area under the receiver operator characteristic curve (AUC) and an index of adequacy (relative prognostic content) of each measure, on the basis of the likelihood ratio chi-square statistic, were computed to evaluate the performance of NEDOCS and EDWIN. RESULTS: There were 130 completed sampling times over ten days. The OV indicated that the ED was overcrowded 62% of the time. The AUC for the NEDOCS was 0.83 (95% CI = 0.75 to 0.90), and the AUC for the EDWIN was 0.80 (95% CI = 0.73 to 0.88). The NEDOCS score accounts for 97% of the prognostic information provided by combining all variables used in each model into one combined model. The EDWIN score accounts for only 86% (chi2 test for difference, p = 0.02). CONCLUSIONS: Both scales had high AUCs, correlated well with each other, and showed good discrimination for predicting ED overcrowding. This establishes construct validity for these scales as measures of overcrowding. Which scale is used in an ED is dependent on which set of data is most readily available, with the favored scale being the NEDOCS.

Chi-Square Distribution↗
PubMed1992

Differential effects of congenital versus acquired unilateral brain injury on dichotic listening performance: evidence for sparing and asymmetric crowding.

We assessed dichotic speech and complex-pitch discrimination in nine young patients with unilateral left-hemisphere injury and eight young patients with unilateral right-hemisphere injury incurred in the pre-perinatal (congenital) period. As in adults with acquired unilateral lesions, both congenital lesion groups demonstrated poor performance on stimuli presented to the ear contralateral to the lesion. In overall performance on speech discrimination, however, the left-hemisphere congenital lesion group performed significantly better than the acquired-lesion group did. On complex-pitch discrimination, the right-hemisphere congenital lesion group performed significantly better than did the acquired-lesion group, but both left- and right-hemisphere congenital lesion groups were significantly worse at complex-pitch discrimination than were their age- and gender-matched normal controls. These results indicate that although congenital damage produces a "lesion effect" in dichotic listening similar to that after damage acquired in adulthood, overall function is relatively spared. To the extent that complex-pitch discrimination is affected by congenital damage to either hemisphere but speech discrimination is not, the present results are consistent with an asymmetric form of crowding during reorganization after congenital unilateral brain damage.

Adolescent↗
PubMed1988

The role of HMG CoA reductase and dolichol synthesis in the control of 3T6 cell proliferation: effects of cell crowding, serum depletion and addition of epidermal growth factor.

The proliferation of 3T6 cells was substantially decreased when the monolayer cultures were allowed to reach confluency. This growth inhibition (so-called density-dependent inhibition) was of the same magnitude as that following serum depletion in non-confluent cultures. Each type of growth inhibition was correlated to a depression of the activity of 3-hydroxy-3-methyl-glutaryl coenzyme A (HMG CoA) reductase, an enzyme that regulates the biosynthesis of cholesterol and isoprenoid derivatives (e.g. dolichol) by catalysing the reduction of HMG CoA (which is derived from acetyl-CoA) into mevalonate. However, the depression of enzyme activity was more substantial in cells exposed to cell crowding than that in serum-depleted cells (87 and 48%, respectively). On the other hand, there was a 60-65% inhibition of the incorporation of mevalonate into dolichol due to serum deprivation, while it remained at normal level in confluent cultures, which implies that the inhibitory effects on dolichol synthesis due to these two experimental conditions were approximately equipotent. Addition of epidermal growth factor (EGF) to the cell cultures, whose proliferation was inhibited due to serum depletion, restored DNA synthesis completely, and these effects were related to a normalization of the activity of HMG CoA reductase and of the incorporation of mevalonate into dolichol. In contrast, in confluent cells addition of EGF only caused a slight increase in DNA synthesis and activity of HMG CoA reductase, and there was no significant increase in the incorporation of mevalonate into dolichol either.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2002

Late lower arch crowding: the aetiology reviewed.

This article reviews the causes of the crowding that commonly occurs, particularly in the lower arch, after eruption of the second permanent molars. Factors discussed include mesially directed forces, in treated and untreated subjects, distally directed forces, occlusal changes, direction of eruption, tooth morphology, periodontal forces, and degenerative connective tissue changes.

Adolescent↗
PubMedDate not supplied

Insuring low-income adults: does public coverage crowd out private?

During the mid-1990s Minnesota, Washington State, Oregon, and Tennessee implemented programs to provide subsidized health insurance for low-income persons who were not previously eligible for Medicaid. We estimate the effects of these programs on the health insurance status of low-income adults in these states. We find that among persons with family incomes below 100 percent of the federal poverty level, subsidized public coverage reduced the number of uninsured persons with very little effect on private coverage rates. Among persons with income between 100 percent and 200 percent of FPL, public coverage reduced the number of uninsured persons and crowded out some private insurance. The partial successes achieved by these programs should be kept in perspective: Even after program implementation, approximately 30 percent of low-income adults in the four states were uninsured.

Adult↗
PubMed2006

Simulation of molecular crowding effects on an Alzheimer's beta-amyloid peptide.

Fibril formation by the Alzheimer's beta-amyloid (Abeta) peptide in brain tissue is integral to the Alzheimer's disease pathology. Understanding the conformational properties and the mechanisms triggering aggregation of the Abeta peptides, at an atomic level of detail, is of crucial importance for the design of effective therapeutic agents against this disease. In this work, the conformational transitions and dynamic properties of an amyloidogenic peptide fragment (Abeta10-35) were studied by molecular dynamics simulations in systems modeling infinite dilution and the presence of macromolecular crowding agents (CA). The model system consists of the peptide described with an atomistic force field, the CA represented by inert, quasi-hard spheres and a continuum solvent model. This combined model allowed the simulations to be extended to 100 ns each. Simulations were carried out starting from a completely extended structure, a beta-strand structure, and four nuclear magnetic resonance structures in dilute aqueous solution. For all structures, two additional simulations were performed that included the inert CA in the solution and occupied approx 30 and 40% of the volume, respectively. For two of the nuclear magnetic resonance structures, additional simulations were carried out with 35% volume fraction of CA to further examine the diffusive behavior of the peptide. The peptide adopted a collapsed coil conformation in all simulations. The results of the simulations in dilute solution showed reasonable qualitative agreement with experimental and other simulation results, whereas the presence of volume excluding agents resulted in some distinct changes in properties (e.g., an increase in the appearance of transient beta-structure or decreases in diffusivity with increasing CA concentration). At the same time, internal motion such as order parameters or atomic root mean square fluctuations showed less systematic responses to volume exclusion.

Amyloid beta-Peptides↗
PubMed2006

The Northwestern twin chorionicity study: testing the 'placental crowding' hypothesis.

OBJECTIVE: To evaluate the relation between placental proximity and frequency of birth weight discordance and small-for-gestational age (SGA) infants. STUDY DESIGN: Retrospective three-tier chorionicity analysis of 1155 twin placentas comparing birth weight characteristics of the twins in different placental types. RESULTS: Dichorionic-separate, but not dichorionic-fused twins, are heavier than monochorionic-diamniotic and monoamniotic twins (2376+/-721 vs. 2274+/-770, P < 0.006, and 2376+/-721 vs. 2166+/-782, P < 0.04). SGA twins are less frequent among dichorionic twins (OR 0.4; 95% CI 0.3, 0.6). Fewer sets with two SGA infants are present among dichorionic-separate compared to monochorionic-diamniotic pairs (OR 0.3; 95% CI 0.1, 0.8). The same trends are found when comparing all dichorionic to all monochorionic twins. Twins of all placental types have similar gestational ages and discordance values. CONCLUSIONS: Dichorionic-separate placentas are least likely to experience 'placental crowding' and thus are associated with heavier twins and fewer sets with one or two SGA infants.

Adult↗
PubMed2005

Anomalous diffusion of proteins due to molecular crowding.

We have studied the diffusion of tracer proteins in highly concentrated random-coil polymer and globular protein solutions imitating the crowded conditions encountered in cellular environments. Using fluorescence correlation spectroscopy, we measured the anomalous diffusion exponent alpha characterizing the dependence of the mean-square displacement of the tracer proteins on time, r(2)(t) approximately t(alpha). We observed that the diffusion of proteins in dextran solutions with concentrations up to 400 g/l is subdiffusive (alpha < 1) even at low obstacle concentration. The anomalous diffusion exponent alpha decreases continuously with increasing obstacle concentration and molecular weight, but does not depend on buffer ionic strength, and neither does it depend strongly on solution temperature. At very high random-coil polymer concentrations, alpha reaches a limit value of alpha(l) approximately 3/4, which we take to be the signature of a coupling between the motions of the tracer proteins and the segments of the dextran chains. A similar, although less pronounced, subdiffusive behavior is observed for the diffusion of streptavidin in concentrated globular protein solutions. These observations indicate that protein diffusion in the cell cytoplasm and nucleus should be anomalous as well, with consequences for measurements of solute diffusion coefficients in cells and for the modeling of cellular processes relying on diffusion.

Biophysics↗
PubMed2005

Na+ shows a markedly higher potential than K+ in DNA compaction in a crowded environment.

Whereas many physicochemical investigations have shown that among monovalent cations Na(+) ion possesses minimal potential for DNA binding, biological assays have shown that Na(+) ion (in contrast to K(+) ion) plays a primary role in chromatin compaction and related processes. It is difficult to explain this inverse relationship between the compaction potentials of Na(+) and K(+) and their binding abilities. In this study we sought to resolve this contradiction and emphasize the phenomenological distinction between DNA compaction and DNA binding processes in the case of DNA compaction by monocations. Using polyethylene glycol solutions as a model of a crowded cell environment, we studied DNA compaction by alkali metal salts LiCl, NaCl, KCl, RbCl, and CsCl, and found that all of these monocations promote DNA compaction. Among these monovalent cations Na(+) produces the greatest compaction and the ratio of K(+) cand Na(+) oncentrations for DNA compaction is approximately 1.5-2. A comparative analysis of recent experimental results indicates that a higher binding activity of monocation generally corresponds to a low compaction potential of the corresponding monovalent ion. This inverse relation is explained as a result of partial dehydration of monocations in the compact state.

Bacteriophage T4↗
PubMed1985

[Experimental production of myeloschisis associated with hindbrain crowding in the central nervous system of rat fetuses by a single intragastric administration of ethylenethiourea].

66 pregnant rats were divided into 9 groups according to gestation day 11 to 19. These pregnant rats were subjected to a single intragastric administration of ethylenethiourea (ETU) and cesarian sectioned on day 20. No dam died following the ETU treatment, but the rate of fetal death was as high as 21.2% on day 11, followed by a gradual decrease in the fetal death rate thereafter. The rate of production of various types of externally visible malformations was 100% except in the fetuses of dams treated with ETU on gestation day 19. The important results were as follows. (I) Fetuses of dams treated with ETU from gestation day 11 were found to suffer from a high incidence of myeloschisis associated with hindbrain crowding. (II) Exencephaly and an abnormally enlarged head with occipital bossing due to herniation of the mesencephalic tectum, with and without dilatation of the mesencephalic and 4th ventricle, were induced among the fetuses of dams given ETU at gestation day 12 and 13. (III) Various degrees of hydranencephaly and dysgenic hydrocephalus were found among the fetuses of dams treated with ETU from gestation days 14 to 18. The above results suggest that ETU may be a useful agent for the production of congenital malformations in the rat.

Abnormalities, Drug-Induced↗
PubMed1997

Shigellosis on Indian reserves in Manitoba, Canada: its relationship to crowded housing, lack of running water, and inadequate sewage disposal.

OBJECTIVES: This study compares incidence and hospitalization rates for shigellosis between Indians and the rest of the population in Manitoba, Canada. It examines the relationship between shigellosis and environmental conditions on reserves. METHODS: Rates were calculated with surveillance data and a survey of environmental infrastructure was done. RESULTS: Indians had shigellosis incidence and hospitalization rates that were 29 and 12 times as high, respectively, as those of the rest of the population. Household crowding, lack of piped water, and inadequate sewage disposal were significantly associated with an increased incidence of shigellosis on reserves. CONCLUSIONS: Many cases of shigellosis may be prevented by improving living conditions on Indian reserves.

Adolescent↗
PubMed2003

The effect of breed and intrauterine crowding on fetal erythropoiesis on day 35 of gestation in swine.

In a previous report, it was suggested that intrauterine crowding impaired fetal erythropoiesis and that fetal erythropoiesis was accelerated in Meishan pigs during early pregnancy. Because these conclusions were based on limited numbers of observations, the present experiment was undertaken to provide a more extensive investigation of these phenomena. Intact white crossbred gilts, unilaterally hysterectomized-ovariectomized (UHO) white crossbred gilts, and intact Meishan gilts (n = 13 to 16 per group) were mated after at least one estrous cycle of normal duration (17 to 23 d). Gilts were laparotomized at d 35 of pregnancy, the uterine horns were exteriorized and opened near each fetus, and a blood sample was collected from each fetus. The uterine horn was then surgically removed, and each fetus and placenta was weighed. All fetal blood samples were measured for hematocrit, red blood cell number, and hemoglobin. Erythropoietin and the percentages of nucleated cells and reticulocytes were also measured in blood samples from the largest and smallest living fetus in each litter. Fetal hematocrits were not affected by treatment. Blood cell counts were greater (P < 0.01) in fetuses of Meishan gilts than in White crossbred intact or UHO gilts. Hemoglobin was less (P < 0.01) in fetuses of Meishan gilts than in fetuses of White crossbred intact or UHO gilts. The percentages of nucleated (immature) cells and reticulocytes were both less (P < 0.01) in fetuses of Meishan intact gilts. Erythropoietin was also lower (P < 0.01) in fetuses of Meishan gilts. As observed previously, fetal weight was correlated (r = 0.38; P < 0.01) with blood hemoglobin concentration. These results confirm that fetal erythropoiesis in Meishan gilts is accelerated compared with White crossbred gilts. These results are consistent with the hypothesis that faster blood cell development could be beneficial to fetal survival in swine.

Animals↗
PubMed2002

Participation in a public insurance program: subsidies, crowd-out, and adverse selection.

This paper examines how varying the level of subsidies affects participation in a public insurance program, crowd-out of private insurance, and adverse selection. We study the experience in Washington's Basic Health program in 1997. Findings show that adverse selection is not a problem in voluntary public programs. Increasing subsidies have only modest effects on participation in subsidized programs, though the gains are not at the expense of the private market. Overall participation in the subsidized plan is also modest, even though participants benefit from it. The challenge to policymakers is to find program design characteristics, beyond subsidies, that attract the uninsured.

Adolescent↗
PubMed1994

A clearing in the crowd: innovations in emergency services.

Emergency department overcrowding may not be so much a result of inappropriate use of the emergency department as it is a problem of the unavailability and inaccessibility of primary care services in the community. The prevailing theory that people use the emergency department because they cannot afford care elsewhere does not hold true. The vast majority of patients surveyed as part of the Emergency Services Initiative had some type of coverage, primarily Medicare or Medicaid. Without additional primary care capacity to accommodate walk-in patients and to make appointments available within one to two weeks, emergency departments will remain over-crowded. In addition to increasing primary care capacity, services must be structured to be as convenient and amenable to patient use as the emergency department. The findings of the Emergency Services Initiative supports the Preferred Primary Care Provider guidelines for the assignment of a primary practitioner or team to each patient, 24-hour telephone access for medical advice, evening and weekend hours, accommodation of walk-in patients, and the provision of nonurgent appointments within a maximum of two to four weeks. In addition, easy access to ancillary services for lab tests and X rays is beneficial for attracting patients. Patient education is also necessary. Questioning by counselors indicated that patients often do not understand that primary care settings are more appropriate than the emergency department for treatment of minor health problems. The most effective way to implement change in the health care system may not be through broad, generic prescriptions but through well-designed programs tailored to specific sites and communities. Changing staff behavior is often as challenging as changing patient behavior. Pre-project planning and communication about purpose, scope, and procedures are necessary if projects are to begin and continue smoothly. Ongoing evaluation is also key.

Community-Institutional Relations↗
PubMed1996

Special report. Bombs, bomb threats, and crowds: how Atlanta hospitals met the security challenges of the 1996 Olympic Games.

Despite immense crowds and the early-morning bomb blast that killed two and injured more than 100 persons during the summer Olympics in Atlanta, GA, months of preparation and some good weather protected local health care facilities from serious problems, according to security directors of five major Atlanta hospitals. Here are details of how these hospitals dealt with the additional security problems presented by the Olympics, including the Centennial Park bombing and a number of bomb threats.

Anniversaries and Special Events↗
PubMed1999

Influence of section thickness, mean nuclear diameter and nuclear crowding on DNA ploidy in histologic sections of melanocytic skin lesions.

OBJECTIVE: To determine the influence of section thickness, nuclear diameter (MND) and area percentage of nuclei (a measure of nuclear crowding) on histologic DNA ploidy assessed by image cytometry (ICM) of primary melanocytic skin neoplasms (MSNs). STUDY DESIGN: Initially a feasibility study was performed to determine if comparable DNA ploidy histograms could be obtained from cell disaggregates and tissue sections. Following this, DNA ICM was performed on Feulgen-stained tissue sections (4, 6, 8 and 10 microns thick) from 30 primary MSNs (20 benign, 10 malignant) with nuclear diameters from 5.6 to 8.6 microns. Area percentage of nuclei was assessed in all cases at all section thicknesses. RESULTS: The feasibility study produced comparable results for cytocentrifuge and tissue section preparations. For sectioned MSNs, DNA ploidy histograms from 4-micron sections had a higher coefficient of variation of the 2c peak than those from 6-, 8- and 10-micron sections. Ten-micrometer sections had marked overlapping of nuclei, and only small numbers of cells could be measured, giving inadequate results. MND and area percentage of nuclei did not have an important influence on the results. CONCLUSION: Adequate DNA ploidy profiles can be obtained by DNA ICM on 6- and 8-micron-thick histologic sections of MSNs, provided that a strict measurement protocol is followed.

Cell Count↗
PubMed1999

Aberrant eruption and its relationship to crowding: the need for early detection and management.

A modular, fixed-functional method has been described using a new generation of appliances that are smaller, more comfortable and more patient friendly, while gaining the advantages of a combined fixed-functional and postural therapy. The case has been made for the middle mixed dentition as the optimal starting time. Crowding, overbite and molar rotation are managed simply with a combined use of flexible lip bumpers, bite plane and sequential primary tooth extraction. In conclusion, Phase I Postural Therapy will be shown to have the following advantages: more biologically and patient friendly more conducive to non-extraction more efficient and cost effective simple fabrication and reduced chair time reduced Phase II fixed appliance time, and completion at a younger age.

Child↗
PubMed2000

Non-extraction treatment of a thirteen-year-old boy with a Class III skeletal discrepancy and severe crowding in both the upper and lower dentitions.

A thirteen-year-old boy presented with a Class III skeletal tendency in association with severe crowding in both the upper and lower arches. Whilst there was not a frank posterior crossbite, it was felt that the upper arch was narrow and that the lower arch was similarly constricted. Taking this into account along with the fact that his upper lip was flat and the nasolabial angle obtuse, it was decided to pursue a non-extraction treatment, with the aim of providing by expansion an extra 16 mm of space in the upper arch and 8 mm in the lower arch to accommodate the full dentition, and with a view to extracting third molar teeth later. This proved to be successful, albeit over an extended period of time, with active treatment taking nearly three and a half years. A realistic alternative would have been to remove four bicuspid teeth and pursue an orthodontic/surgical approach to treatment. In retrospect, and with the benefit of reviewing his records without surgical intervention, the treatment plan decided upon has been well justified.

Adolescent↗