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At least 1,711 records · Page 95Linked to original sources
PubMed1995

Characteristics of objects that cause choking in children.

OBJECTIVE: To characterize the types, shapes, and sizes of objects causing choking or asphyxiation in children and to compare these characteristics to current standards. DESIGN: To evaluate morbidity, retrospective 5-year medical record survey; to evaluate mortality, data reanalysis. SETTINGS: Pediatric hospital and consumer product testing laboratory. PATIENTS: All children (n = 449) who underwent endoscopy for foreign body aspiration or ingestion at Children's Hospital of Pittsburgh (Pa) between 1989 and 1993 and children (n = 449) whose deaths due to choking on man-made objects were recorded by the Consumer Product Safety Commission (CPSC) between 1972 and 1992. MAIN OUTCOME MEASURES: Objects removed from children's aerodigestive tracts were characterized by location, procedure for removal, and type. Objects causing death were characterized by type, shape, and consistency. Three-dimensional objects that had caused asphyxiation were analyzed by computer-simulated models. RESULTS: Of the 165 children treated by endoscopy, 69% were 3 years of age or younger. Foreign bodies most often ingested or aspirated were food (in 36 children) and coins (in 60 children). Of 449 children whose deaths after aspirating foreign bodies were reported to the CPSC, 65% were younger than 3 years. Balloons caused 29% of deaths overall. Conforming objects such as balloons caused a significantly (P < .001) higher proportion of deaths in those aged 3 years or older (60%) vs those younger than 3 years (33%). Of the 101 objects causing deaths that we could analyze, 14 met current standards for use by children of any age. CONCLUSIONS: Balloons pose a high risk of asphyxiation to children of any age. Changes in regulations regarding products intended for children's use might have prevented up to 14 (14%) of 101 deaths in this study.

Adolescent↗
PubMed1995

The mouse mutation reeler causes increased adhesion within a subpopulation of early postmitotic cortical neurons.

Early postmitotic cortical neurons are mostly corticofugal projection neurons that take up positions in deep cortical laminae. Later postmitotic neurons are preferentially localized to superficial cortical laminae. In reeler mutant mice it appears that cortical laminar positions with respect to birthdate are reversed (Caviness, 1982). In a reanalysis of reeler lamination we found that early postmitotic cortical neurons labeled by embryonic day (E) 11-13 injections of a birthdate marker, or by early postnatal day (PND) 2 retrograde labeling through their output projections, appear to take up positions both in the superficial and deep cortex. Neurons born on E11 and E12 are more likely to be situated superficially in the reeler cortex and neurons born on E13 are more likely to be situated in the deep reeler cortex. Many corticofugal projection neurons in the deep (but not superficial) reeler cortex either die or retract their axons before PND 21. We hypothesize that the earliest postmitotic (E11-E12) of the early postmitotic reeler cortical neurons are overly adhesive and act as a barrier to later postmitotic migrating neurons. In vitro cortical aggregation cultures confirmed that early postmitotic (E12) reeler neurons are more adhesive than early postmitotic (E12) wild-type neurons or late postmitotic (E16) reeler or wild-type cortical neurons. We suggest that the moderate wild-type preferential adhesion of early postmitotic cortical neurons to each other helps deep and superficially fated lineages to form cortical laminae.

Animals↗
PubMedDate not supplied

Management of menopause in women with breast cancer.

It is now well established that replacement therapy with estrogen is an effective tool to manage menopausal symptoms. There is also increasing evidence that hormone replacement therapy has beneficial effects on the long-term consequences of estrogen deficiency, such as osteoporosis and ischemic heart disease. However, breast cancer patients have been traditionally denied the beneficial effects of hormone replacement therapy (HRT) because of the belief that renewed hormonal exposure would accelerate the growth of occult breast cancer or facilitate breast carcinogenesis. Based on new data and reanalysis of old data, a reappraisal of this belief has recently been proposed. Reports on a small number of patients who did receive HRT with no apparent effect on their breast disease warrant large-scale prospective studies on this issue. Meanwhile, pharmacological and "natural" alternatives to hormonal treatment are also available for breast cancer patients.

Breast Neoplasms↗
PubMed1995

Enzyme-linked immunoabsorbent assay detection of a soluble form of urokinase plasminogen activator receptor in vivo.

The receptor for urokinase plasminogen activator (uPA-R, CD87) is a glycosylphosphatidylinositol (GPI)-anchored 50 to 65 kD glycoprotein that, by regulating membrane-associated plasmin activity, may facilitate the invasion of inflammatory and malignant cells. Certain other GPI-anchored glycoproteins are shed from the cell membrane and exist as soluble products in vitro and in vivo. To determine if uPA-R undergoes a similar phenomenon, we have developed a sensitive enzyme-linked immunoabsorbent assay (ELISA) (using a rabbit antiserum as both capture and detection reagents) to measure the quantity of soluble uPA-R (suPA-R) in tissue culture supernatants and biologic fluids. Using this ELISA, we have detected suPA-R in the culture supernatants of U-937 cells and human monocytes stimulated in vitro by certain soluble inflammatory mediators (Sitrin et al, Blood 84:1268, 1994; Mizukami et al., Clin Res 42:115A, 1994). To determine if suPA-R exists in vivo, we have screened the plasma of 20 normal volunteers (mean +/- SD, 3 +/- 3 ng/mL; median, 2 ng/mL; range, 1 to 11 ng/mL [serum values slightly higher]); the plasma of 13 ICU patients with clinical sepsis syndrome (mean +/- SD, 30 +/- 11 ng/mL; median, 11 ng/mL; range, 4 to 221 ng/mL); and the extravascular fluids (pleural, pericardial, and peritoneal) of 84 individuals with presumed inflammatory or malignant conditions (mean +/- SD, 21 +/- 39 ng/mL; median, 10 ng/mL; range, 2 to 253 ng/mL). Among the latter specimens, most were inflammatory exudates (only six were malignant by positive cytology) with the highest quantities of suPA-R associated with neutrophilic exudates. The solubility of suPA-R contained within these fluids was confirmed by reanalysis after ultracentrifugation to remove particulate material. When tested in a uPA ligand capture ELISA, representative specimens of extravascular body fluids and sepsis plasma contained suPA-R capable of binding uPA ligand (generally representing a small fraction of the immunoreactive material). We conclude from these data that suPA-R is immunologically detectable in vitro and in vivo with high concentrations of receptor found under conditions of inflammatory stimulation. The possibility of suPA-R's biologic activity is suggested by its partial retention of ligand binding capacity.

Adult↗
PubMed1994

Hysterectomy vs. resectoscopic endometrial ablation for the control of abnormal uterine bleeding. A cost-comparative study.

This study compared the costs of endometrial ablation using the uterine resectoscope to those of hysterectomy in a group of patients treated for abnormal uterine bleeding who were enrolled in a national managed health care organization. The cost of endometrial ablation during the periprocedural period was significantly lower than that of hysterectomy, with much of the difference coming from the hospitalization required for the latter procedure. The postprocedural cost for ablation was higher than for hysterectomy owing to the need for second ablations or hysterectomy in 13 of the 85 ablation patients. Preprocedure costs were not different between ablation and hysterectomy. A reanalysis of the data, however, that excluded patients who required a second ablation or hysterectomy suggested that these additional procedures were responsible for the higher postprocedural costs in the ablation group. Resectoscopic endometrial ablation for the treatment of abnormal uterine bleeding resulted in lower periprocedure costs and lower overall treatment costs to the health plan in the groups studied as compared with hysterectomy. Greater familiarity with the technique of resectoscopic endometrial ablation, improved patient selection for the procedure and the use of appropriate pharmacotherapy for suppressing endometrial growth prior to ablation probably substantially improve the rate of success, reduce postprocedural costs and further enhance the cost advantage of this procedure.

Adult↗
PubMed1994

Jews and their intraethnic differential vulnerability to affective disorders, fact or artifact? I: An overview of the literature.

The observation that Ashkenazim have higher rates of affective disorders than either Sephardi or Oriental Jews was reanalyzed from the available literature. Statistical reanalysis of these studies was consistent with rates being elevated for Ashkenazim. The results of these treatment-based studies, however, suffer from biases due to differential help-seeking patterns, lack of accounting for readmission rates, diagnostic unreliability, misuse of frequency ratios relative to other disorders and failure to control for confounding variables. As a result of these causes for biases and in the absence of a true incidence or prevalence study serving as a basis for these observations, the assumption that Ashkenazim are at an increased risk for affective disorders is questionable and may be a mere result of methodological artifacts.

Bipolar Disorder↗
PubMed1994

Relationships between mitotic delay and the dose rate of X radiation.

Upon exposure of cells to radiation delivered at a continuous low dose rate, cell proliferation may be sustained with the cells exhibiting a constant doubling time that is independent of the total dose. The doubling time or mitotic delay under these conditions has been shown to depend on the dose rate in HeLa, V79 and P388F cells (Mitchell et al., Radiat. Res. 79, 520-536, 1979; Fox and Gilbert, Int. J. Radiat. Biol. 11, 339-347, 1966). Reanalysis of the data for these particular cell lines shows that there is a threshold dose rate for mitotic delay, and that above the threshold there is a linear relationship between the length of mitotic delay and the logarithm of the dose rate which is referred to as the dose-rate response. We have observed the same relationships for L5178Y (LY)-R and LY-S cells exposed to low-dose-rate radiation. The threshold dose rates for LY-R, LY-S and P388F cells are similar (0.01-0.02 Gy/h) and are much lower than for V79 and HeLa cells. The slope of the dose-rate response curve is the greatest for HeLa cells, followed in order by LY-S, V79 and P388F cells, and finally by LY-R cells. The slopes for HeLa and LY-R cells differ by a factor of 35.

Animals↗
PubMed1993

Ignorability and coarse data: some biomedical examples.

Heitjan and Rubin (1991, Annals of Statistics 19, 2244-2253) define data to be "coarse" when one observes not the exact value of the data but only some set (a subset of the sample space) that contains the exact value. This definition covers a number of incomplete-data problems arising in biomedicine, including rounded, heaped, censored, and missing data. In analyzing coarse data, it is common to proceed as though the degree of coarseness is fixed in advance--in a word, to ignore the randomness in the coarsening mechanism. When coarsening is actually stochastic, however, inferences that ignore this randomness may be seriously misleading. Heitjan and Rubin (1991) have proposed a general model of data coarsening and established conditions under which it is appropriate to ignore the stochastic nature of the coarsening. The conditions are that the data be coarsened at random [a generalization of missing at random (Rubin, 1976, Biometrika 63, 581-592)] and that the parameters of the data and the coarsening process be distinct. This article presents detailed applications of the general model and the ignorability conditions to a variety of coarse-data problems arising in biomedical statistics. A reanalysis of the Stanford Heart Transplant Data (Crowley and Hu, 1977, Journal of the American Statistical Association 72, 27-36) reveals significant evidence that censoring of pretransplant survival times by transplantation was nonignorable, suggesting a greater benefit from cardiac transplantation than previous analyses had found.

Age Factors↗
PubMed1993

Consumption and harm: drinking patterns of the Irish, the English and the Irish in England.

There has been controversy over the relationship between alcohol consumption and related problems amongst the Irish in England. Irish migrants have high Standardised Mortality Ratios for chronic liver disease and cirrhosis and high hospital admission rates for alcohol-related diagnoses in England. Yet it has been considered that people from the Republic of Ireland, whether living in Ireland (Conniffe et al., 1990) or in England (Pearson et al., 1991), actually drink less than the English. This paper reviews the evidence. In recent years Irish per capita volume alcohol consumption has been comparable to that of the U.K., although the distribution of consumption differs. Women in Ireland are less likely to drink than women in England and Wales, while men in Ireland are more likely to drink at high-risk levels than men in England and Wales: their average weekly consumption levels are closer to those of high-consuming men in Yorkshire and Humberside, who also drink more than the U.K. national average. Men in Ireland also appear to be more likely to experience drinking problems than their counterparts in England and Wales, although this may be related to factors other than the total amount of alcohol consumed. Although a previous study of General Household Survey data indicated low-risk alcohol consumption levels for people from the Irish Republic living in Britain, a reanalysis of these data adjusting for age and gender shows drinking rates that are very high.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Cholescintigraphy in the diagnosis of acute cholecystitis: morphine augmentation is superior to delayed imaging.

Morphine-augmented radionuclide hepatobiliary imaging has been used as an alternative to delayed imaging for the diagnosis of acute cholecystitis. Previous studies have indicated that the morphine-augmentation is as useful as, or more useful than, delayed imaging. A careful comparison of the efficacy of the two techniques appears warranted because: (1) most early studies did not compare the efficacy of the two techniques in a single report using comparable patient populations; (2) the reported efficacy of morphine-augmentation is based primarily on study designs which excluded cases of early gallbladder visualization without morphine, while most delayed imaging protocols included these cases; and (3) there were concerns about the potential consequences of a false-negative morphine examination. This study compared the efficacy of morphine-augmentation with delayed imaging in those cases in which the gallbladder was not visualized during the first hour of study. Of 306 consecutive patients who were scanned to rule out acute cholecystitis, the gallbladder was visualized within 1 hr in 215 cases. In the remaining 91 cases, 46 patients had delayed imaging (17 true-positive, 10 true-negative, 19 false-positive and 0 false-negative), and 45 had morphine-augmentation (24 true-positive, 15 true-negative, 4 false-positive and 2 false-negative). The data indicate that delayed imaging has a significantly lower specificity and positive-predictive value for acute cholecystitis than morphine-augmentation and a slightly higher (statistically insignificant) sensitivity and negative-predictive value. These results appear to be supported by a reanalysis of the data that has already been reported in the literature.

Acute Disease↗
PubMed1993

Modern approach to the evaluation of combined effects of single-dose trials and clinical time-course studies, exemplified by combinations of pirenzepine and H2-receptor antagonists.

A modern approach to the evaluation of combined effects of two active drugs, A and B, in clinical trials is described, based on modern understanding of actions and interactions of drugs which act at distinct molecular sites. It rests on a comparison of observed combined effects with calculated effects of independent action of A plus B--greater than independent effects are considered as a potentiated response. It is illustrated by reanalysis of single-dose and time-course studies of the antisecretory action of pirenzepine and H2-receptor antagonists (cimetidine, ranitidine). Briefly, peptone-stimulated acid output was measured in 15 min periods over 3 h after the injection of drugs in three trials, one with five duodenal ulcer patients, two of them with 8 healthy volunteers each. The doses of pirenzepine and H2-blockers were fixed in each trial. The results were either expressed by the total acid output (single-dose analysis) or by the acid secretion over 15 min as time course. The results with the drug combination show greater reduction in acid secretion in all three trials with respect to independent effects. The time-course studies more clearly showed greater reduction in acid output than the analysis of total acid output, not the least with respect to p-values of differences between observed combined effects and calculated independent effects. They were obtained by the chi-square (chi 2) goodness-of-fit test, recently applied for the evaluation of dose-response curves.(ABSTRACT TRUNCATED AT 250 WORDS)

Cimetidine↗
PubMed1993

[Overweight and obesity in Chilean women. A multivariate characterization based on psychophysiologic indicators].

This paper presents a reanalysis of previously collected data using multivariate statistical methods. Aside from confirming the discrimination between obese, and normal-weight women through psychometric indicators including a personality evaluation, and a verbal affective expression assessment, the power of multivariate methods for improving diagnosis is illustrated.

Case-Control Studies↗
PubMed1993

Violations of the ceiling principle: exact conditions and statistical evidence.

The National Research Council recommended the use of the ceiling principle in forensic applications of DNA testing on the grounds that the ceiling principle was believed to be "conservative," giving estimates greater than or equal to the actual genotype frequencies in the appropriate reference population. We show here that the ceiling principle can fail to be conservative in a population with two subpopulations and two loci, each with two alleles at Hardy-Weinberg equilibrium, if there is some linkage disequilibrium between loci. We also show that the ceiling principle can fail in a population with two subpopulations and a single locus with two alleles if Hardy-Weinberg equilibrium does not hold. We give explicit analytical formulas to describe when the ceiling principle fails. By showing that the ceiling principle is not always mathematically reliable, this analysis gives users of the ceiling principle the responsibility of demonstrating that it is conservative for the particular data with which it is used. Our reanalysis of VNTR data bases of the FBI provides compelling evidence of two-locus associations within three major ethnic groups (Caucasian, black, and Hispanic) in the United States, even though the loci tested are located on different chromosomes. Before the ceiling principle is implemented, more research should be done to determine whether it may be violated in practice.

Alleles↗
PubMed1993

Influence of genotype-dependent effects of covariates on the outcome of segregation analysis of the body mass index.

Several recent studies of the body mass index (BMI) have provided support for a recessive major gene influencing heaviness in humans. Segregation analysis of the BMI was carried out recently in a series of randomly sampled French-Canadian families to determine whether we could replicate the major gene finding by using a residual phenotype adjusted for the effects of age and sex. The best model included a recessive major effect for high BMI values with residual familial resemblance; however, Mendelian transmission could not be confirmed, and the no-transmission hypothesis (where all the tau's are constrained to be equal) was not rejected. Considering that the BMI is a complex phenotype affected by many factors and that there are known variations in body composition during growth and aging, we undertook a reanalysis of the data, using a model that allowed the estimation of genotype-specific age and gender effects. New tests on the transmission parameters satisfy the criteria for interfering Mendelian segregation. The results suggest that individuals with the "high" recessive genotype show the greatest degree of heaviness at birth, with a subsequent trend toward lower values throughout life, while individuals with the dominant "normal" genotypes show no appreciable trends with age. In addition, the "high" genotype appears to confer a greater degree of heaviness in females as compared with males. These results, along with other observations from the data, suggest that, while a recessive single gene influence may be discernible, the phenotypic expression of the BMI is likely to be complicated by genotype x environment interactions and, possibly, by the action of other loci. Further, the data also are consistent with the hypothesis that modifying factors may include the adoption of a more prudent life-style by individuals genetically predisposed to heaviness and a secular increase in the incidence, prevalence, and potency of environmentally based triggers leading to a higher penetrance of the "heavy" genotype in the young.

Adolescent↗
PubMedDate not supplied

Contraceptive efficacy of the diaphragm, the sponge and the cervical cap.

A reanalysis of data from two clinical studies--in which 1,439 women were randomly assigned to use either the contraceptive sponge or the diaphragm and 1,394 women were randomly assigned to use either the cervical cap or the diaphragm--found first-year probabilities of failure during typical use of 17% for the sponge, 18% for the cervical cap and 13-17% for the diaphragm. The first-year probabilities of failure during perfect use are 11-12% for the sponge, 10-13% for the cervical cap and 4-8% for the diaphragm. The probability of failure during perfect use is significantly higher among women who have given birth than among those who have not for users of the sponge (19-21% vs. 9-10%) and users of the cervical cap (26-27% vs. 8-10%), but not for users of the diaphragm.

Contraceptive Devices, Female↗
PubMed1993

Substance abuse testing of urine by GC/MS in scanning mode evaluated by proficiency studies, TLC/GC, and EMIT.

Using GC/MS in scanning mode as a screening and definitive identification methodology for substance abuse testing, 4500 urine samples have been analyzed. The accuracy and sensitivity of this method was evaluated by the results of 92 proficiency sample analyses, reanalyses by TLC screening with GC confirmation of 125 samples from forensic sources and reanalysis by EMIT screening for seven groups of drugs confirmed by GC/MS of 590 samples from industrial and treatment sources. The results of these studies are presented.

Amphetamine↗
PubMed1993

Probing the meaning of racial/ethnic group comparisons in crack cocaine smoking.

OBJECTIVE: To probe the meaning of reported racial and ethnic group differences in the prevalence of crack cocaine smoking and to estimate the degree to which crack cocaine smoking is associated with personal factors specific to race/ethnicity. DESIGN: Through reanalysis of data from the 1988 National Household Survey of Drug Abuse (NHSDA), we compared racial/ethnic group differences in crack cocaine smoking. To hold constant social and environmental risk factors that might potentially confound racial comparisons, we used an epidemiologic strategy that involves poststratification of respondents into neighborhood risk sets. A conditional logistic regression model was used to estimate the relative odds of crack use by race/ethnicity. PATIENTS OR OTHER PARTICIPANTS: The 1988 NHSDA interviewed 8814 individuals residing within households in the United States. Subjects were selected using a multistage area probability sampling of all residents aged 12 years and older. RESULTS: Once respondents were grouped into neighborhood clusters, the relative odds (RO) of crack use did not differ significantly for African Americans (RO, 0.85; 95% confidence interval [Cl], 0.37 to 1.93) or for Hispanic Americans (RO, 0.88; 95% Cl, 0.47 to 1.67) compared with white Americans. CONCLUSION: Findings of race-associated differences are often presented as if a person's race has intrinsic explanatory power. This analysis provides evidence that, given similar social and environmental conditions, crack use does not strongly depend on race-specific (eg, biologic) personal factors. Although the study finding does not refute the previous analysis, it provides evidence that prevalence estimates unadjusted for social environmental risk factors may lead to misunderstanding about the role of race or ethnicity in the epidemiology of crack use. Future research should seek to identify which characteristics of the neighborhood social environment are important and potentially modifiable determinants of drug use.

Adolescent↗
PubMed1993

Recovery from radiation damage in mouse lung: interpretation in terms of two rates of repair.

A reanalysis was performed of the extensive data set obtained with fractionated irradiations of mouse lung reported by Travis et al. (Int. J. Radiat. Biol. 52, 903-919, 1987). The possibility was investigated that the poor fit of these data to the linear-quadratic model might have been the result of the presence of two rates of repair of sublethal damage instead of one. Therefore, the incomplete-repair linear-quadratic model was adapted to incorporate two independent rates of repair and the data were analyzed using this two-component incomplete-repair model. The results which are subjected to certain qualifications with respect to the assessment of the validity of the confidence limits indicated the presence of two significantly different repair rates, corresponding to a fast-repair half-time (t1/2) of 0.40 h (0.28, 0.53) and a slow t1/2 of 4.01 h (1.55, 6.57). A weight factor determined simultaneously indicated that the fast component has approximately four times more weight than the slow component. The alpha/beta value calculated for the entire data set using the same model was 3.8 Gy (3.0, 4.6), which is not significantly different from the alpha/beta of 3.6 Gy (2.8, 4.5) calculated for the 8- and 12-h data only, using the complete-repair linear-quadratic model. An experiment specifically designed to test the significance of the fast-repair component was performed in which mouse lungs were irradiated with two equal dose fractions, separated by intervals ranging from 10 min to 6 h. Data obtained from this experiment allowed only one repair rate to be determined, corresponding to a t1/2 of only 0.4 h. This finding confirms the presence of a very fast repair rate in mouse lung.

Animals↗