Search PubMed⌕ Search

Biomedical subjects

B Brown

Publications and source records attributed to B Brown.

At least 19 recordsLinked to original sources
PubMed1992

Detection of coronavirus RNA and antigen in multiple sclerosis brain.

Epidemiological studies of patients with multiple sclerosis (MS) and animal model data support the hypothesis that viruses initiate the immunopathogenic events leading to demyelination in MS. There have been no reports, however, of consistent detection of viruses in MS central nervous system tissue. We probed MS and control brain with cDNA probes specific for human, murine, porcine, and bovine coronaviruses. We report the in situ hybridization detection of coronavirus RNA in 12 of 22 MS brain samples using cloned coronavirus cDNA probes. In addition, tissue was screened for coronavirus antigen by immunohistochemical methods; antigen was detected in two patients with rapidly progressive MS. Significant amounts of coronavirus antigen and RNA were observed in active demyelinating plaques from these two patients. These findings show that coronaviruses can infect the human central nervous system and raise the possibility that these viruses may contribute to the pathogenesis of MS in some patients.

Antigens, Viral↗
PubMed1992

Properties of soluble CR2 in human serum.

A soluble form of complement receptor number 2 (sCR2) found in human serum closely resembles that produced in culture by B lymphoblastoid cells. Epitope analysis with a panel of CD21 monoclonal antibodies revealed only minor differences between antigen from the two sources. Purified sCR2 from both sources bound to C3dg prepared from human or mouse serum and to u.v.-inactivated Epstein-Barr virus. SDS-PAGE analysis of culture supernates of B-lymphoid cells labelled by growth in medium containing 35S-methionine revealed a major component of molecular weight approximately 130 kDa and another band at 30 kDa. Incubation with endoglycosidase F reduced the size of the high molecular weight component. Gel filtration of untreated serum or culture supernate revealed that, in its native state, sCR2 behaved as a molecule or complex of apparent molecular weight 320 kDa. Possible explanations are discussed.

B-Lymphocytes↗
PubMed1992

Mobility of normal observers under conditions of reduced visual input.

The importance in mobility performance of the rate of presentation of visual information, binocular versus monocular vision, the use of multiple rather than single reference points, and local motion parallax was investigated in two experiments. In each experiment ten subjects walked a triangular mobility course in a totally darkened room; the only visible targets were light emitting diodes (LEDs), mounted on poles, at the apices of the triangle. The LEDs were mounted so that one or two could be used in a trial; if two were used the distance between them was varied horizontally (in experiment 1) and vertically (in experiment 2). The subjects walked around the course under a range of conditions, including two 'optimal trials' in full light. The LEDs were flashed for 1 ms at frequencies of 0.5, 1 and 5 Hz in experiment 1 and at 1 and 5 Hz in experiment 2. Mobility was measured with the use of an ultrasonic locator system which measured the subject's position on the course 10 times per second. The mean velocity of the subject in traversing the course was significantly reduced when the flash rate was slower, when the subject had one eye occluded, or when there was only one LED on the pole; when the spacing between the LEDs was varied, either vertically or horizontally performance was unaffected. These results imply that the frequency of updating of visual information is important in determining mobility performance, as are binocular cues, but that local motion parallax is not important. The number of LEDs on each pole had a significant effect on mobility performance an 'object' (two lights) gave more information than a point reference.

Adult↗
PubMed1992

Response rates in a survey of physical capacity among older persons.

A representative sample of 420 subjects aged 55 to 84 was sought for participation in a study of the relationship between physical activity and health. A stratified random sample with 35 subjects in each of 12 age-gender categories was designed, using lists generated consecutively until the target number for each category was reached. Although the protocol required walking and treadmill tests, 60.3 percent of those eligible participated, a figure comparable to that of NHANES II and superior to that of the Canada Fitness Survey. Participants were younger, more likely to be male, less likely to be currently married, and more likely to have had a white-collar job and some postsecondary education than were nonparticipants. Difficulties of obtaining subjects and methods for avoiding these difficulties include offering many opportunities to attend and determining accurately the reason for nonparticipation.

Age Factors↗
PubMed1992

Reliability of the tear break-up time technique of assessing tear stability and the locations of the tear break-up in Hong Kong Chinese.

The measurement of tear break-up time (TBUT) in assessing stability of the tear film is somewhat controversial, even though the technique is widely used. We examined reliability of the technique within and among examiners and conclude that measurements of TBUT can be made reliably; full-beam observation of the cornea is preferable to scanning the cornea with a narrow slit in making the measurements. There may be differences in TBUT measurements made in the same subjects among examiners, but these differences are smaller with more experienced practitioners. In the Hong Kong Chinese (HK-Chinese), tear break-up appears to be more likely to first occur in the inferior periphery of the cornea. In this population mean TBUT is about 7.20 s; assuming a Gaussian distribution of TBUT values, 2.1 s should be adopted as the lower limit for normal TBUT in HK-Chinese.

Adolescent↗
PubMed1992

Journal keeping as an educational strategy in teaching psychiatric nursing.

Personal attitudes and self-awareness are key issues of which the psychiatric nursing student must be aware when establishing a therapeutic relationship. Facilitating awareness and growth in these areas are fundamental challenges for the nurse educator. One potential teaching strategy with which to address this issue is journal keeping. This paper describes a study evaluating the impact of journal keeping on student nurses' attitudes toward psychiatric clients and self-awareness in relations with others. Third-year nursing students completing a psychiatric rotation kept journals which were used to reflect on thoughts and feelings engendered by their clinical experience. Two student control groups were used: one completing a psychiatric rotation without keeping journals and the second completing a medical-surgical rotation. All students completed the Opinions About Mental Illness, the Fundamental Interpersonal Relations Orientation-Behaviour, and Comfort in Working with Psychiatric Clients Scales prior to and at the end of their clinical experience. Findings support the use of journals to assist students in exploring and changing their attitudes but not necessarily in changing their interpersonal style.

Adult↗
PubMed1992

Evaluation of teaching: a review of the literature.

Although most faculty members would agree that teaching is a vital component of their role, the evaluation of teaching continues to receive less attention than the evaluation of other academic pursuits. This paper reviews the nursing and education literature related to the evaluation of teaching. The bulk of the literature reviewed focused on the following: current issues of faculty evaluation, appraisal criteria of effective teaching, and evaluators of teaching effectiveness. The paucity of literature related to the process of faculty evaluation provides further evidence that there is a gap between what institutions say is important and what is actually practised. The implementation of faculty evaluation models may be one remedy to this current problem.

Employee Performance Appraisal↗
PubMed1992

Consequences of teen-age parenting.

The changing context of teen-age childbearing and current related controversies are reviewed. Recent research about the consequences of teen-age childbearing for the teen-age mother, the father, and for the children born is examined. The article also summarizes current knowledge about the consequences of teen-age childbearing with regard to the mother's educational attainment, marital experience, subsequent fertility behavior, labor force experience and occupational attainment, and experience with poverty and welfare.

Adolescent↗
PubMed1992

Long-term follow-up of patients with node-negative breast cancer treated only by regional therapy.

BACKGROUND: This study examines the potential impact of intercurrent diseases on survival after adjuvant chemotherapy for node-negative (N0) breast cancer in light of 30-year follow-up results in 136 patients with N0 disease receiving only regional therapy at the University of Texas M.D. Anderson Cancer Center between 1958 and 1960. METHODS: We made a retrospective review of treatment records. RESULTS: Thirty-nine women (28.6%) died of the initial breast cancer, including 12 (22%) of 54 premenopausal women, 15 (43%) of 35 perimenopausal women, and 12 (25%) of 47 postmenopausal women (p less than or equal to 0.09). Six (12%) of 49 patients with T1 disease died of the initial breast cancer versus 27 (38%) of 70 patients with T2 disease and 6 (35%) of 17 patients with T3 disease (p less than or equal to 0.006). Five of 10 women died of metachronous contralateral breast primary lesions. Deaths from other cancers occurred in 11%, 2.8%, and 6.4% of premenopausal, perimenopausal, and postmenopausal women, respectively. Deaths from nonmalignant conditions occurred in 22%, 20%, and 59% of premenopausal, perimenopausal, and postmenopausal women, respectively. Overall survival at 30 years was 35 (26%) of 136 patients. CONCLUSIONS: Given these statistics, if one postulates that adjuvant chemotherapy reduces the death rate from an initial breast cancer by 30% to 77% (estimates based on data from adjuvant chemotherapy trials in patients with N+ or N0 disease), a 5% to 12.9% increase in the 30-year survival would have resulted.

Adult↗
PubMed1992

How the elderly fare in HMOs: outcomes from the Medicare competition demonstrations.

Because of concern about the effects of prepaid care on outcomes for elderly enrollees in health maintenance organizations (HMOs), a prospective study of access to care and functional outcomes was performed. HMOs with Medicare risk contracts in January 1985 (N = 17) were selected from ten communities and were matched for comparison with ten similar communities where no Medicare HMOs were in operation. Random samples of HMO enrollees (N = 2,098) and fee-for-service (FFS) nonenrollees (N = 1,059) were assessed at baseline and at follow-up one year later (HMO = 1,873, FFS = 916) to observe access to care and functional outcomes. At baseline, nonenrollees had more bed days and poorer functional status than HMO enrollees. While fewer HMO enrollees experienced declines in functional status between baseline and follow-up (e.g., patient's ability to function declined in one or more activities of daily living: HMOs at 5.3 percent versus FFS at 8.5 percent, p < .01), after controlling for other factors with logistic regression, enrollment status was not significantly associated with functional decline. Self-rated health, history of hospitalization, age of 80 or older and baseline functional status were predictive of decline in function. After controlling for baseline differences, HMO disenrollees also experienced similar functional declines at follow-up compared to continuously enrolled beneficiaries. These findings suggest that Medicare beneficiaries who belong to HMOs experience comparable rates of functional decline to those experienced by beneficiaries in the FFS sector with similar initial levels of function and health status. Together with results showing no significant difference in medical visits according to various symptoms, we conclude that access and quality of care delivered by HMOs is comparable to that provided in FFS settings.

Activities of Daily Living↗
PubMed1992

Tolerance to spherical aberration induced by rigid contact lenses.

We have investigated the effects of spherical aberration (SA) on visual performance by fitting subjects with rigid lenses of varying front surface asphericity. Three pairs of lenses were worn by each subject with front surface asphericities of Q = 0 (conventional spherical surface), Q = -0.26 (similar to the average corneal asphericity) and Q = -0.51. The calculated average change in spherical aberration induced by each pair of contact lenses in photopic conditions was +0.02 D (Q = 0), -0.49 D (Q = -0.26) and -0.94 D (Q = -0.51). In mesopic conditions these same lenses induced an average change in spherical aberration of +0.01 D (Q = 0), -1.18 D (Q = -0.26) and -2.16 D (Q = -0.51). In this double-blind study, 12 adapted, low to moderate myopic rigid lens wearers wore each pair of lenses for one week and noted visual performance. With each pair of lenses we also measured the subject's visual acuity with high and low contrast logMAR charts. All measurements were conducted using the right eye at distance in photopic and mesopic conditions. When forced to select the lenses they would accept as compensation for participation in the study, most subjects (9 out of 12) chose the Q = 0 lenses, 3 subjects those the Q = -0.26 lenses and none of the subjects chose the Q = -0.51 lenses. Visual performance measures showed little difference between the Q = 0 and Q = -0.26 lenses. However, the Q = -0.51 lenses significantly reduced visual acuity in mesopic conditions with the low contrast acuity chart.

Contact Lenses↗
PubMed1992

Sonographic diagnosis of the large for gestational age fetus at term: does it make a difference?

We evaluated 406 women with late third-trimester ultrasound examinations to determine whether the sonographic diagnosis of a large for gestational age (LGA) fetus, defined as an estimated fetal weight at or above the 90th percentile, altered the management of labor and delivery. The sonographic prediction of LGA fetuses had a sensitivity, specificity, and positive predictive value of 50, 90, and 52%, respectively. Women without the sonographic diagnosis of an LGA fetus (N = 338) differed from those with the diagnosis (N = 68) in the frequency of diagnosed labor abnormalities (19 versus 30%, P = .03), use of epidural anesthesia (57 versus 74%, P = .01), and the incidence of cesarean deliveries (32 versus 53%, P = .004). To determine whether it was the sonographic prediction of an LGA fetus or the actual fetal weight that altered clinical management and perinatal outcomes, we stratified the study population into four groups and compared the true negatives with the false positives and the false negatives with the true positives. The incorrect sonographic diagnosis of an LGA fetus had a statistically significant effect on both the diagnosis of labor abnormalities (P = .04) and the incidence of elective cesareans (P = .04) in pregnancies with appropriate for gestational age birth weights.

Cesarean Section↗
PubMed1991

Psychosocial adjustment in women with breast cancer.

There is a plethora of studies investigating psychosocial adjustment in women with breast cancer, its correlates, clinical course, and prognosis. These studies have been conducted with varying degrees of methodologic rigor. An assessment has been made of the quality of this existing evidence to identify from the best evidence the factors which predict the adjustment status of women with breast cancer. Studies have been reviewed, using methodologic standards for the critical appraisal of studies on prognosis, developed by Sackett and colleagues in the Department of Clinical Epidemiology and Biostatistics at McMaster University (Hamilton, Ontario, Canada). Few of the studies investigating psychosocial adjustment of women with breast cancer meet all of the criteria for reviewing studies of clinical course and prognosis. This review focuses the direction and methodologic rigor required in future investigations. In particular, studies are needed that employ prospective designs and that deliberately measure or control for the extraneous prognostic variables that may affect adjustment. Future investigations need to incorporate adequate precision in measurement so that measures of the psychosocial variables are objective, reliable, and valid.

Adaptation, Psychological↗
PubMed1991

Autotransfusion of unwashed mediastinal shed blood fails to decrease banked blood requirements in patients undergoing aortocoronary bypass surgery.

Infusion of unwashed mediastinal shed blood (MSB) is one technique advocated for decreasing use of donor blood in cardiac surgery patients. A commercially available system was prospectively evaluated in 96 consecutive patients. The control group was comprised of 78 consecutive patients. All underwent elective aortocoronary bypass surgery. Student's t-test, chi-square analysis, multivariate analysis, and Fisher's exact test were used where appropriate. There was no decrease in the amount of banked blood required or percentage of patients who received transfusions in the MSB autotransfusion group.

Blood Banks↗
PubMed1991

Predicting the future position of a moving target.

Three experiments were conducted to examine the processes underlying the prediction of the future position of a moving target. A target moved horizontally across a computer screen at constant velocity, disappearing partway across the screen, and subjects responded when they estimated the target would have passed a point on the far side of the screen, had it continued on its path. The first experiment demonstrated that visual tracking of the target is not necessary for successful position estimation. In the second experiment, the time over which the prediction was made rather than the interval for which the target was visible, the distance over which the prediction was made, or the velocity of the target, was found to affect performance. Finally, performance was not affected when markers were placed parallel to the trajectory of the target; the presence of gratings which masked portions of the target's path did not affect subjects' performance. The previous literature suggests that the spatial interval over which predictions are made is the important variable; we find that temporal factors are the major determinants of prediction.

Acceleration↗
PubMed1991

Neurosurgery image manager.

Computer technology has become standard in many areas of medical practice, but computer-assisted instruction has not replaced standard textbooks and didactic lectures. This paper describes the development of a computer image-based educational system designed for neurosurgical instruction. The advantages and applications of this system for both clinical and academic use and the required software and hardware requirements are delineated. This computerized tutorial can organize and manipulate large amounts of data. The Neurosurgery Image Manager system contains an introductory help section, a self-assessment test in neurosurgery, and a data base of images from the video disc "The Slice of Life," produced at the University of Utah. Questions are taken from the Self-Assessment in Neurological Surgery series. Additionally, the system contains a reference index for all material in the tutorial, a scored clinical problems section, and a several hundred word glossary. The system is programmed using the Macintosh Hypercard authoring system. Large data bases can be manipulated and linked with graphics, text, and peripherals. Images are stored using the MacVision II digitizing system. The hardware necessary to operate the system and the method of implementation of Neurosurgery Image Manager are described. The prototype Neurosurgery Image Manager has been accepted by the Joint Committee on Education of the American Association of Neurological Surgeons and Congress of Neurological Surgeons as one of the computer formats for the next self-assessment tests.

Computer Graphics↗