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Biomedical subjects

J A Bean

Publications and source records attributed to J A Bean.

At least 19 recordsLinked to original sources
PubMed1992

A pilot study of a new ELISA test for ciguatoxin in humans.

The major impediment to the thorough study of Ciguatera in human populations has been the lack of definitive diagnostic ability. However, recently an ELISA test was developed which can diagnose Ciguatera qualitatively and quantitatively in human fluids, as well as in contaminated fish tissue. This study proposes to evaluate this new ELISA test in human subjects with the clinical diagnoses of acute and chronic Ciguatera Poisoning. The contaminated fish from exposed subjects, and the blood and urine of exposed and controls, will be examined using the new ELISA. The ELISA performance will be compared to traditional bioassays for the fish testing. In addition, a distinct diagnostic profile will be developed using serial questionnaires, physical examinations, and nerve conduction tests. Ultimately this ELISA test can be used not only in establishing the correct diagnosis of Ciguatera Poisoning, but also in the treatment and clinical prognosis, and in epidemiologic studies of Ciguatera Poisoning in human populations. We hope that this protocol will serve as a model for the study of the effects of other marine toxins on human populations.

Adult↗
PubMed1991

Oncologists' reluctance to accrue patients onto clinical trials: an Illinois Cancer Center study.

Clinical trials are recognized as the standard of care for the cancer patient, and the randomized, controlled trial represents the most definitive method to determine the effectiveness or ineffectiveness of a cancer treatment. However, less than 3% of all eligible patients enter a clinical trial. Of the 437 physician members of the Illinois Cancer Center (ICC), 244 responded to a survey designed to determine factors that present a significant barrier to entering patients on clinical trials. Rigid protocol design was the primary deterrent to accrual, especially for medical oncologists. Surgeons, radiation oncologists, and medical oncologists differed with respect to several factors, including willingness to seek a clinical trial, tendency to treat patients off study, quality-of-life issues, and the belief that trials were too excessive in time commitment (P less than .05). Compared with hospital-based physicians, community oncologists had fewer patients on trial, were more likely to enter patients on the basis of age, and were more concerned about aspects of informed consent and the financial burden of a trial (P less than .01). One third of the physicians never pursued a clinical trial because of conflict with the priorities of individual care and excessive follow-up time. Fourteen percent indicated that they discouraged patients from participating in a clinical trial due to the risk of a patient receiving a placebo and patient follow-up requirements (P less than .05). Subgroups of physicians differ in their reluctance to accrue patients, and there are clusters of beliefs expressed by physicians concerning their clinical trial activity. Current conduct of clinical trials needs to be reassessed, and intervention studies are required to determine the best methodology to alter physician reluctance to pursue clinical trials.

Attitude of Health Personnel↗
PubMed1988

Epidemiology of premenstrual symptoms in a nonclinical sample. I. Prevalence, natural history and help-seeking behavior.

A stratified sample of 996 nursing school graduates from 1963 to 1984 was surveyed by mail regarding menstrual cycle characteristics. The 730 respondents reported an 87% overall lifetime prevalence of premenstrual symptoms. When the symptoms were categorized according to severity, only 3.2% of the respondents reported severe symptoms. Symptomatic women used diet change (24.6%), exercise (41.8%) and vitamins (18.9%) as self-help measures. Seventeen percent sought advice from a physician. Drug use was common; 22% were using a drug for symptoms at the time of the survey. Despite the common use of treatment, few women reported a significant work impairment. These findings support the conclusion that premenstrual symptoms are common but do not usually interfere with functioning.

Adult↗
PubMed1986

Ultrasound characterization of acute myocardial ischemia by quantitative texture analysis.

In this study we tested the efficacy of quantitative texture analysis in the identification of acute myocardial ischemia using an ultrasound data acquisition system that digitizes and stores echocardiographic data in polar format. In nine closed-chest dogs, data were acquired before and after coronary occlusion using a 2.4 MHz echocardiographic system. Regions of interest were analyzed at end-diastole and end-systole from the ischemic area and normal area at the same depth of field. Ultrasound data were evaluated using previously reported quantitative gray level texture measures. After occlusion, texture changes indicative of ischemia were found in systolic images. The directional component of the data analysis was important; analysis in the azimuthal direction was more accurate than in the axial direction. Six texture measures exhibited significant changes in the ischemic region from control to occlusion when analyzing data in the azimuthal direction. One false positive result occurred (significant texture change in the normal region from control to occlusion) in the azimuthal direction. Several false positive alterations in the normal regions from control to occlusion were found when the texture was evaluated in the axial direction. For accurate assessment of ischemic changes, preocclusion image data were required. We conclude that quantitative echocardiographic texture analysis using polar format data can identify subtle changes in myocardial texture such as that due to acute ischemia, using data acquired through the chest wall.

Acute Disease↗
PubMed1986

Sample size for case-control studies using Cochran's statistic.

Sample size determination for case-control studies of chronic disease are often based on the simple 2 X 2 tabular cross-classification of exposure and disease, thereby ignoring stratification which may be considered in the analysis. One consequence of this approach is that the sample size may be inadequate to attain a specified power and size when performing a statistical analysis on J 2 X 2 tables using Cochran's (1954, Biometrics 10, 417-451) statistic or the Mantel-Haenszel (1959, Journal of the National Cancer Institute 22, 719-748) statistic. A sample size formula is derived from Cochran's statistic and it is compared with the corresponding one derived when the data are treated as unstratified, and also with two other formulas proposed for stratified data analysis. The formula developed yields values slightly higher than one recently proposed by Muñoz and Rosner (1984, Biometrics 40, 995-1004), which assumes that both margins of each 2 X 2 table are fixed, while the present study considers only the case-control margin to be fixed.

Biometry↗
PubMed1979

Probability of menopause with increasing duration of amenorrhea in middle-aged women.

The empirical percent probability that natural menopause has occurred after first presentation of amenorrhea of various durations in women greater than or equal to 45 years of age has been calculated using data from a cohort of subjects who prospectively recorded menstrual flow and related gynecologic events. The probability that menopause has occurred increases with the amenorrheal interval (duration), and for a given interval, the probability increases with age. After 180 days of amenorrhea, 45% to 72% of subjects were menopausal; after 360 days, 90%. These data may offer assistance in advising patients on the probability of menopause and the continuance of contraceptive practices, and in considering whether late genital bleeding after amenorrhea represents a physiologic or pathologic process.

Age Factors↗
PubMed1979

Postvaccine era measles epidemiology.

Measles incidence in the United States was calculated from estimates of the United States Immunization Survey for the years 1965 to 1975. These data were examined according to birth cohorts and cross-sectionally by age to determine the effect of live measles virus vaccine on measles epidemiology. The results showed a high rate of infection for children aged 1 year, followed by a decrease in the infection rates for preschool children, with rates increasing agin at ages 5 and 6 years. It was hypothesized that an effective vaccine-induced herb immunity exists in preschool children until they are of school age. When incidence rates were based on susceptible children, the highest rates occurred in the school-aged populations.

Age Factors↗
PubMed1979

A computer program for survival comparisons to a standard population.

PROPHAZ is a computer program created for the analysis of survival data using the general proportional hazards model. It was designed specifically for the situation in which the underlying hazard function may be estimated from the mortality experience of a large reference population, but may be used for other problems as well. Input for the program includes the variables of interest as well as the information necessary for estimating the hazard function (demographic and mortality data). Regression coefficients for the variables of interest are obtained iteratively using the Newton-Raphson method. Utilizing large sample asymptotic theory, x2 statistics are derived which may be used to test hypotheses of the form C beta = 0. Input format is completely flexible for the variables of interest as well as the mortality data.

Computers↗
PubMed1979

Effects of true and inverted feedback on integrated occipital alpha.

Ambient illumination had no effect on baseline levels of alpha of 20 female university students who had their eyes closed, and significant increases from these levels were obtained through true but not inverted feedback procedures. These results indicate that alpha enhancement can be obtained in a manner that is not explicable in terms of disinhibition processes.

Adolescent↗
PubMed1979

Variations in the reporting of menstrual histories.

This investigation examined the accuracy of recall of females to questions concerning ages at memarche, natural and surgical menopause, first use of oral contraceptives and mean menstrual cycle length and variance. A sample of 160 women who had recorded their menstrual and reproductive events as they occurred were administered a questionnaire concerning these events, with responses compared to the original data. For the variables age at menarche, age at natural memopause, age at surgical menopause and age at first use of oral contraceptives, the percentage of women who correctly recalled within a year ranged from 75% to 90%. Recollection of menstrual cycle length and variability by interview was considered unreliable. These findings are encouraging regarding the ability to recall the age when certain menstrual and reproductive events occur, but not for menstrual cycle intervals or patterns. Because these women were well-educated and had once recorded study variables, these results might be considered optimal.

Adult↗
PubMed1979

A performance comparison: USMG-FMG attending physicians.

To determine whether patterns of differences in performance exist between United States Medical Graduate and Foreign Medical Graduate attending Physicians, two types of inpatient hospital audits (Payne Process Audit and the Joint Committee on Accreditation of Hospitals' Performance Evaluation Program-P.E.P. Audit) were conducted in 22 Maryland and Pennsylvania non-federal, short-term hospitals. A total of 6,980 medical records were abstracted from eight diagnostic categories for 1,321 attending physicians; 985 of which were USMGs and 331 were FMGs. The results from both audits indicate that while there is evidence of a strong hospital-type of physician interaction for many of the diagnoses, there was no significant overall difference in performance between USMG and FMG attending physicians. The largest and most consistent differences in physician performance were associated with hospital characteristics, not physician characteristics.

Clinical Competence↗
PubMed1979

Changes in heart rate following eyes-closed alpha enhancement.

Subjects (n = 20 females 18 to 26 yr. old) who had been trained in an eyes-closed alpha-enhancement task were grouped according to performance and changes in heart rate were compared. Subjects who showed a facility for producing alpha also evidenced a small decrease in heart rate while a small increase in heart rate while a small increase in heart rate was shown by the low alpha-output group.

Adolescent↗
PubMed1978

Resting levels of alpha and the Eysenck Personality Inventory.

The number of microvolt seconds of alpha rhythm emitted during a five-minute period were collected for 30 male and 30 female subjects. This measure of alpha abundance was then compared in subjects who scored high and in those who scored low on the E and N scales of the Eysenck Personality Inventory. Subjects who scored low on the E scale tended to have a significantly greater number of microvolt seconds of alpha than did subjects who scored high on the scale. No differentiation on the basis of emitted alpha was possible for subjects scoring high and low on the N scale.

Adolescent↗
PubMed1978

Menstrual cycle patterns and breast cancer risk factors.

Using a data set of women who longitudinally recorded menstrual and reproductive events, we examined menstrual cycle characteristics in relationship to early and late menarche, early and late menopause, and deferred parity, three variables epidemiologically related to breast cancer incidence. Women with late onset of menarche had longer and more variable cycles in the 10 years after menarche than did those with early onset. Women with late onset of menopause had longer and more variable cycles in the premenopausal interval than did those with early onset. Cumulative fertility in women after marriage did not differ according to cycle length and variance. Late menopause may be a breast cancer risk factor due to relative estrogen excess and progesterone lack as reflected in longer, more varied cycle patterns. Observed cycle differences between women with early and late menarche await further study of the endocrine physiology of the menstrual cycle in those groups.

Adolescent↗