Fission and quasifission in U-induced reactions.
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Journal Article↗
Biomedical subjects
N Herrmann
Publications and source records attributed to N Herrmann.
Reaction Mo+Mo between 12 and 18.8 MeV/u: Approaching the limits of the deep-inelastic process.
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Journal Article↗
Curtailed binomial sampling procedures for clinical trials with paired data.
The use of curtailed sampling procedures in designing clinical trials with a dichotomous response and paired data is reviewed. Tables of expected sample size savings and a simple to evaluate asymptotic formula for the expected sample size savings are presented where the sample size savings is calculated relative to the fixed sample size test. Comparisons are made among fixed sample size, curtailed, and repeated significance hypothesis testing procedures. In view of the substantial savings in sample size available under certain conditions and the accuracy of the approximating formula, it is recommended that curtailed procedures be given serious consideration in the design of clinical trials.
Clinical Trials as Topic↗
Retrospective information from questionnaires. I. Comparability of primary respondents and their next-of-kin.
The author compared medical, smoking, and dietary consumption data obtained from cases or controls and their respective next-of-kin as part of a study of colon cancer in the five Pennsylvania counties of the Philadelphia metropolitan area. The case population consisted of whites aged 45-69 years who had resided in the region for at least two years prior to diagnosis and diagnosed with colon cancer after July 1, 1976. Controls were selected using an area probability sampling scheme and were frequency-matched to the case group. Questionnaires for cases and controls were administered by interviewers; questionnaires for their next-of-kin were randomly allocated to be self- or interviewer-administered. Agreement when both respondents received the interviewer-administered questionnaire was greater than when the next-of-kin received the self-administered questionnaire for all variables. Medical and cigarette smoking variables exhibited high agreement, the percentage agreement exceeded 80 for 80% of the comparisons, the kappa statistic exceeded 0.6 for 54% of the comparisons. Diet histories were more variable (average agreement ranging from 54% to 82% and average kappa values from 0.17 to 0.59). A subanalysis of subjects and spouses showed that husbands and wives gave equally reliable responses.
Aged↗
Retrospective information from questionnaires. II. Intrarater reliability and comparison of questionnaire types.
Medical and dietary consumption histories obtained at two times from cases or controls and their next-of-kin as part of a study of colon cancer in the five Pennsylvania counties of the Philadelphia metropolitan area were compared. The case population was confined to whites aged 45-69 years who had resided in the region for at least two years prior to diagnosis and were diagnosed with colon cancer after July 1, 1976. Controls were selected using an area probability sampling scheme and were frequency-matched to the case group. Questionnaires for randomly selected subsamples of cases and controls were administered by interviewers; questionnaires for next-of-kin were randomly allocated to be self- or interviewer-administered. Agreement when respondents received the interviewer-administered questionnaire at both interviews was greater than when the self-administered questionnaire was used. Medical variables exhibited high agreement, the percentage agreement exceeded 80 for over 80% of the comparisons, the kappa statistic exceeded 0.6 for half of the comparisons. Diet histories were more variable (average agreement ranging from 56% to 67% and average kappa values from 0.16 to 0.40 for the different comparisons).
Beverages↗
Seroprevalence of zoonotic toxocariasis in the United States: 1971-1973.
Demographic characteristics associated with human Toxocara canis infection in children aged one to 11 years were investigated using data from the Health and Nutrition Examination Survey of 1971 to 1973. An enzyme-linked immunosorbent assay with larval stage antigen was used to measure the concentration of antibodies to T. canis in 1,409 available sera. From 4.6 to 7.3% of the children in different geographic regions of the United States have been infected, with serologic prevalence approaching 30% among black children of lower socioeconomic status aged six to 11 years. For both blacks and whites, higher seroprevalence was associated with a rural residence, increased age in children and number of persons in the household, and with decreased income, education, and number of rooms in the house. Multivariate logistic regression models indicated that blacks had higher infection rates than whites, even when socioeconomic factors were controlled. Certain critical variables, however, such as exposure to dogs or reliable pica histories, were not available for analysis.
Age Factors↗
Relationship of prolonged pharmacologic serum levels of vitamin E to incidence of sepsis and necrotizing enterocolitis in infants with birth weight 1,500 grams or less.
The incidence of culture-proven neonatal sepsis and necrotizing enterocolitis (NEC) in preterm infants maintained at pharmacologic (mean 5.1 mg/dL +/- 1.45 SD) serum vitamin E levels for long periods was prospectively studied as part of a double-masked clinical trial of the effect of prophylactic vitamin E v placebo treatment on the development and course of retinopathy of prematurity (ROP). Within a few days of birth, 914 preterm infants were enrolled in the study; 545 (275 placebo-treated infants, 270 vitamin E-treated infants had birth weight of 1,500 g or less. A significant difference in incidence of neonatal sepsis (17 placebo-treated infants, 37 vitamin E-treated infants) and NEC (18 placebo-treated infants, 32 vitamin E-treated infants) was observed among infants who had been treated for eight or more days and who had developed neither sepsis nor NEC before that time. The association of vitamin E treatment with increased incidence of disease was much higher with sepsis than with NEC. The most likely reason for these observations is a pharmacologic serum vitamin E-related decrease in oxygen-dependent intracellular killing ability which results in a decreased resistance to infection in preterm infants. The data suggest that, if this occurs, it is clinically significant only in the more immature infants. In view of the known variability of absorption of oral vitamin E and the association between high serum vitamin E levels and increased incidence of sepsis and late-onset NEC reported here, it can be concluded that serum vitamin E levels must be monitored when supplemental vitamin E is administered to premature infants, especially those with birth weight 1,500 g or less. The risk-benefit ratio of long-term treatment using vitamin E at high serum levels should be clearly assessed.
Administration, Oral↗
The geriatric rotation: an intern's perspective.
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Aged↗
Laryngeal cancer and occupational exposure to sulfuric acid.
Workers on an ethanol unit which used sulfuric acid in strong concentrations at a large refinery and chemical plant in Baton Rouge, Louisiana were reported, in 1979, at excess risk for upper respiratory cancer. The carcinogen implicated by indirect evidence was diethyl sulfate. However, with the continued use of sulfuric acid in the same plant, and with additional cases not attributable to the ethanol process, the hypothesis of an association between sulfuric acid exposure and upper respiratory cancer was tested. Each of 50 confirmed cases of upper respiratory cancer diagnosed between 1944 and 1980, was matched to at least three controls on sex, race, age, date of initial employment, and duration of employment. Thirty-four of the 50 cases were laryngeal cancers. Data were obtained from existing plant records. Retrospective estimates of exposure were made without regard to case or control status. Findings from conditional logistic regression techniques were supported by other statistical methods. Among workers classified as potentially highly exposed, four-fold relative risks for all upper respiratory cancer sites combined were exceeded by the relative risk for laryngeal cancer specifically. Exposure-response and consistency across various comparisons after controlling statistically for tobacco-use, alcoholism and other previously implicated risk factors, suggest increased cancer risk with higher exposure.
Alcohol Drinking↗
Homogeneously staining regions and tumorigenicity.
A homogeneously staining region (HSR), a chromosome abnormality associated with gene amplification, was found to increase in length coincident with an enhancement in tumorigenicity when cells from a human retinoblastoma cell line were serially passaged in athymic (nu/nu) mice.
Animals↗
Obtaining hospital and physician participation in a case-control study of colon cancer.
This paper describes efforts to solicit hospital and physician participation for a case-control study of the etiology of colon cancer in the five Pennsylvania counties of the Philadelphia metropolitan area. Forty-seven of the 70 hospitals in this region were eligible for inclusion in the study. Thirty-seven (79%) agreed to participate, 27 of them within six months of initial contact. The median time to approval of participation was three months and the median number of separate contacts was nine. At least five participating hospitals submitted the protocol to their lawyers and nine required that special procedures be developed for release of patient information. Two hundred fourteen of 256 listed attending physicians were eligible for participation; 161 (75%) permitted all patients to be contacted 23 (11%) permitted some patients to be contacted; 30 (14%) refused all patient contact. A significant association between type of specialty and type of permission was found (p approximately .005). Concerns about confidentiality and lack of personal advantage were frequently cited by non-participants. The validity of case-control studies relying on hospital or physician ascertainment of cases is seriously challenged by such lengthy delays and lack of participation which can result in a biased pool of potential cases.
Aged↗
Interobserver and intraobserver reliability in the collection of emergency medical services data.
The collection of data by abstraction from patient records is a widely used method of research, evaluation, and registry. Since valid conclusions depend on the accuracy of the abstracted data, it is essential to examine the abstracting procedures. In this paper, we report on a study of patient data abstracted from emergency department records by nurses trained by project personnel. Twenty-five charts were selected at each of five hospitals. To test interobserver reliability, the nurses were asked to abstract all of the charts at each hospital; to test intraobserver reliability, four of the nurses each reabstracted a set of charts. The results show that even with highly trained, well motivated abstractors, there are considerable differences in the accuracy with which the variables are abstracted. Disposition from the hospital, quantitative vital signs, and blood gas values tend to be abstracted with higher reliability; whereas variables requiring judgment, such as character of vital signs or history of disease, tend to have low reliability. To improve the quality of abstracted data, we propose improved retrieval methods for hospital records, monitoring of data collection procedures, cooperation of all medical personnel providing the raw data, and careful selection of variables.
Emergency Service, Hospital↗
Assessing the validity of EMS data.
Variation in the assessment of basic clinical data gathered by emergency medical technicians and emergency department nurses was studied. Prior to testing, precise definitions, categories and procedures were developed and tolerance limits for the quantitative variables were created. Each participant evaluated four consecutive patients simultaneously with another evaluator setting the standard. The results indicate that the error rate is low to moderate for the different variables. For the quantitative variables, the error rate is over 20% and, when an error does occur, it is often very large. This indicates a need for ongoing emphasis on accurate measurement and, in cases where highly accurate data is essential, the use of multiple observers.
Data Collection↗
The use of clock tests in schizophrenia.
Though clock drawing tests are well recognized as measures of cognitive function, there is little data on the performance of patients with schizophrenia. We compared 24 patients with schizophrenia to 24 healthy, age-matched controls on clock drawing, copying, and reading. Patients with schizophrenia performed significantly worse on clock drawing and copying despite the fact that the groups had similar scores on the MMSE. Worse performance was associated with higher scores on the BPRS. Clock drawing and copying may be useful for the assessment of cognition in schizophrenia, and the monitoring of cognitive changes associated with antipsychotic medication.
Adult↗
[Clinical relevance of the tracheal bronchus].
We report about 6 infants with serious respiratory disease who revealed a tracheal bronchus on bronchoscopic or bronchographic examination. In two of these children this finding seemed to be the main problem; it could be cured by surgical or conservative therapy. The course of the further 4 children's disease was determined by additional serious malformations (Oesophageal atresia, congenital heart disease, anomalies of the pulmonary arteries). In these cases, the tracheal bronchus did not influence the clinical course significantly.
Abnormalities, Multiple↗
A correlation between cognitive performance and daily functioning in elderly people.
The Mini-Mental State Examination (MMSE) is widely used to detect dementia, but the diagnosis of dementia also depends on a decline in the level of daily functioning. Little is known about the relationship between performance on the MMSE and daily living abilities. This relationship was investigated in this study of an elderly population by comparing scores on the MMSE with those on both a direct assessment of everyday tasks and an indirect questionnaire about activities of daily living and physical self-maintenance. Forty-five subjects with varying mental abilities participated in the study. A significant correlation was found between MMSE scores and the measures of functional abilities; but the specificity and sensitivity to the diagnosis of dementia would be increased by assessing functional status, even indirectly, as well as cognitive ability.
Activities of Daily Living↗
The effect of age of onset on depression in the elderly.
In an attempt to examine the effects of age and age of onset on depressive illness, the records of 55 psychiatric inpatients with an average age of 77 years were reviewed. There was no correlation between age and presence of psychosis, severe cognitive impairment, positive family history, length of hospitalization, treatment, or treatment response. When the cases were grouped on the basis of age of first admission, only the rates of family history were significantly different. Although age per se may have little influence on the nature of depressive illness, age of onset may be important in distinguishing different types of depressive illness in the elderly, which suggests implications for treatment and prognosis.
Age Factors↗