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Biomedical subjects

R Epstein

Publications and source records attributed to R Epstein.

At least 55 records · Page 3Linked to original sources
PubMed1996

Is school vision screening effective?

A population-based cohort of all children entering kindergarten in a three-year period (N = 2,938) was followed retrospectively from kindergarten through 12th grade to estimate incidence of abnormal school vision screening tests and rates of follow-up by community ophthalmologists or optometrists. Overall 28% of children had at least one abnormal school vision screening test. Abnormal screening with referral increased from 1.2% of five-year-olds to 9.1% of 13-year-olds. Overall, 91% of children referred had further evaluation by eye care professionals. However, visits to an eye care professional often were delayed; median time was 0.8 years for children seeing an ophthalmologist and 1.8 years for children seeing an optometrist. Results support the continued use of simple visual acuity screening in schools. Consideration should be given to screening children beyond age 12 and developing methods to increase the rapidity of parental response to referral recommendations.

Adolescent↗
PubMed1995

Comparison of methods for defining prevalent vertebral deformities: the Study of Osteoporotic Fractures.

Women with vertebral deformities caused by osteoporosis have more back pain and disability and are at higher risk for subsequent vertebral deformities than women without deformities. Despite the importance of vertebral deformities, there has been a great deal of controversy about how to identify or define them. In order to compare methods for defining vertebral deformities, we studied spinal radiographs from women in the Study of Osteoporotic Fractures (SOF), a cohort study of 9704 non-black women over age 65 recruited from population-based listings in four clinical centers. Using radiographs obtained at the baseline exam, we compared five methods for defining vertebral deformities: one based on a semiquantitative reading by a radiologist and four using vertebral morphometry. The semiquantitative method was compared with the other methods in a random sample of 503 films, while the morphometric methods were compared with each other in a larger sample of 9575 films. We tested a system of "triage" in which only those films with evidence of deformity were assessed by morphometry. We compared the relationship between deformity, defined by each method, and a variety of clinical criteria including bone mineral density at the lumbar spine, height loss since age 25, back pain, and incidence of subsequent deformity. Semiquantitative reading and three of the four morphometry-based methods provided similar relationships to clinical criteria. The fourth morphometry method (based on ratios of each vertebral height to the corresponding height at T4) produced significantly weaker relationships for several of the clinical validation criteria. Triage of radiographs rarely resulted in missed deformities and did not reduce the performance of any of the methods. We conclude that use of any of the similar methods, with or without triage, provides a valid approach to defining vertebral deformities.

Aged↗
PubMed1995

Calcium-inducible transmodulation of receptor tyrosine kinase activity.

Calcium is a potent mitogen and transmodulator of growth factor receptor activity, but does not activate tyrosine kinases in ligand-deprived cells (Epstein et al. 1992) Cell Growth Different. 3, 157-164). In this study the mitogenic and transcriptional effects of increased extracellular calcium and ionophore are shown to be identical in 3T3 cells, consistent with mediation of these effects via increased intracellular calcium availability. Near-maximal mitogenic and transcriptional effects are seen after brief exposure to increased extracellular calcium or ionophore, while additive effects occur with co-administration of calcium and platelet-derived growth factor (PDGF). Exposure of PDGF-primed cells to calcium or ionophore is associated with a substantial enhancement of receptor tyrosine autophosphorylation which is abrogated by calcium channel blockade or intracellular calcium chelation. In contrast, pretreatment of quiescent cells with calcium or ionophore significantly diminishes subsequent PDGF-inducible receptor autophosphorylation. Intracellular calcium thus appears to potentiate the kinase activity of ligand-stimulated PDGF receptors while inhibiting ligand-inducible activation of unstimulated receptors. These findings suggest a model of receptor tyrosine kinase regulation involving calcium-dependent positive and negative feedback loops which vary with the activation state of the receptor.

3T3 Cells↗
PubMed1994

Dichotic listening performance under high and low lexical work load in subtypes of developmental dyslexia.

This study examined dichotic listening performance in different subtypes of developmental dyslexia under high and low verbal work load conditions. Free recall tests of digits and words were administered to 320 dyslexic children from grade 3 to grade 10 and their matched controls. Results indicate significant differences within subtypes. Surface dyslexics manifested extreme ear neglect or total performance collapse but only under high verbal work load conditions. Phonological dyslexia was distinguished by poor total performance both under high and low work load levels. Visuo-motor dyslexics, however, did not differ in any measure from their controls. These results lend support to the contention that the main neuropsychological factor impeding reading acquisition varies according to dyslexia subtype.

Adolescent↗
PubMed1994

Six-month results of the multicenter phase I study of excimer laser myopic keratomileusis.

We report six-month results of the Summit Technology Myopic Keratomileusis Phase I multicenter study. Fifty-seven eyes of 57 patients had keratomileusis to correct high myopia. A microkeratome was used for the primary keratectomy and the excimer laser was used to ablate the stroma of the resected lenticle (cap) or the stromal bed (in situ). At six months, 31 of the 47 eyes available for follow-up (65.9%) had uncorrected visual acuity of 20/40 or better; 16 (34.0%) had uncorrected acuity of 20/25 or better. Thirty-seven eyes (78.7%) maintained the same (+/- one Snellen line) best corrected visual acuity as before surgery; seven (14.9%) lost two lines and three (6.4%) lost more than two lines. In addition to the six-month multicenter study results, we report two year results in a subset of 28 eyes (22 from the multicenter study and six fellow eyes). At six months, 17 of the 24 eyes available for follow-up (70.9%) had uncorrected visual acuity of 20/40 or better and nine (37.5%) had uncorrected acuity of 20/25 or better, including eyes that had worse than 20/80 best corrected visual acuity preoperatively. At 24 months, five of the seven eyes available for follow-up (71.4%) had uncorrected acuity of 20/25 or better. Only one patient lost two lines of best corrected vision at six months and no patient lost more than two lines; at 24 months, all patients maintained (+/- one line) best corrected vision.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Actigraphic home-monitoring of the sleep patterns of in vitro fertilization children and their matched controls.

The sleep patterns of 35 in vitro fertilization (IVF) children aged 19 to 57 months and their matched controls were evaluated by actigraphic home-monitoring for three consecutive nights. Actigraphic data were analysed by an automated scoring procedure developed in the authors' laboratory. There were no significant differences in activity levels between IVF multiple-birth subjects and their matched controls or between IVF singletons and their matched controls. In contrast, multiple-birth subjects had higher activity levels during sleep and lower sleep efficiency than singletons in both IVF and control groups. Sleep measures showed night-to-night stability in all groups.

Age Factors↗
PubMed1993

Interviewer versus self-administered questionnaires in developing a disease-specific, health-related quality of life instrument for asthma.

We wished to determine the extent to which respondents provided the same answers to a health-related quality of life (HRQL) questionnaire in self- and interviewer-administered forms. One hundred and fifty patients with asthma who were symptomatic or required treatment at least once a week, and had airway hyperresponsiveness to methacholine aerosol (PC20 < 8.0 mg/ml) participated. Patients completed a 152-item HRQL questionnaire in both interviewer and self-administered forms, separated by a 2-week interval, the order determined by random allocation. The percentage of items endorsed by the self-administered approach was significantly higher than that of the interviewer-administered approach overall (46.9 vs 35.8%) (p < 0.0001). The difference was consistent across all six domains; the absolute difference in the proportion of items endorsed varied from 8.9 to 12.3%. The intraclass correlations for the proportion of subjects endorsing an item was 0.84. Self- and interviewer-administered questionnaires yield very similar results in discriminating between subjects, but the self-administered version shows systematically greater HRQL impairment.

Adult↗
PubMed1993

Children's sleep under the threat of attack by ballistic missiles.

The present paper reports on the influence of the Scud missile attacks during the Gulf War on the sleep of Israeli children. Two studies were performed. In the first, sleep habits and sleep disturbances of 61 (mean age 20 months) infants were assessed by questionnaires completed by their parents 5 months before the war and immediately after the end of the War. Comparison of pre- and post-war data revealed no major changes in sleep habits or in sleep quality. In the second study, sleep of 55 children was monitored at home by actigraphs during the last month of the War. All children were aroused during missile attacks, but returned to sleep immediately, with no evidence of carry-over effects once the 'all clear' sign was given. Comparison of sleep quality measures obtained during the War with those of age- and sex-matched children monitored a year before the war did not reveal any significant differences apart from the immediate response to the attack.

Journal Article↗
PubMed1993

Sleep patterns of children sleeping in residential care, in kibbutz dormitories and at home--a comparative study.

The present study compares sleep patterns of two groups of children sleeping away from their families, in residential care (n = 31, age 3.7 +/- 1.7 years) and kibbutz (n = 29, age 3.7 +/- 1.8 years) dormitories, with age-matched children sleeping at home (n = 21, age 3.7 +/- 1.8 years). Sleep was monitored by wrist-worn actigraphs for three consecutive nights and assessed by sleep questionnaires, which were completed by parents of the kibbutz children and caretakers at residential care. Children in the residential care settled to sleep significantly earlier and slept longer than those children living in a kibbutz or at home. The longest period of uninterrupted sleep was more extended for children sleeping at home, compared to those sleeping in communal dormitories. Correlation analysis between various assessments of sleep and waking behaviors revealed a different pattern for kibbutz and residential care children. For the kibbutz children, there were significant correlations between difficulties falling asleep and various attributes of daytime tiredness. Conversely, in the residential care, difficulties falling asleep were significantly and positively correlated with parameters associated with daytime alertness. This pattern of correlations and the actigraphic data indicate that difficulties in falling asleep for children in residential care are probably a consequence of being put to bed too early and according to a rigid schedule, and not the result of emotional factors.

Child Behavior↗
PubMed1992

Are specific reading and writing difficulties causally connected with developmental spatial inability? Evidence from two cases of developmental agnosia and apraxia.

Two cases studies of subjects suffering from severe developmental constructional apraxia are presented. These two subjects demonstrated normal to high ability in reading, writing and arithmetical tests. The analysis of cognitive tests performed by them indicates that extreme developmental, perceptual, spatial and motor deficits may be dissociated from the acquisition of efficient reading ability.

Achievement↗
PubMed1992

Is the establishing of tolerance to self obligatorily MHC restricted?

The prevailing paradigm used to interpret how T cells recognize antigen treats antigen processing as obligatory because the T cell antigen receptor complex can only detect antigen located in a "groove" found on MHC-encoded restricting elements. The vast majority of experimental systems used to analyze how T cells recognize antigen depend on induced T cells executing their effector functions, and it is agreed without exception that this event is MHC restricted. However, to date, the extrapolation of the obligatory MHC restriction of effector function to the level of the antigen-responsive T cell that makes the tolerance induction decision, depends not on experiment, but on theoretical constructs. The few experiments designed to test whether tolerance is MHC restricted are open to several interpretations, only one of which is consistent with the view that all antigen recognition events must be MHC restricted. If it can be shown that tolerance is not obligatorily MHC restricted, then the pillar of the prevailing paradigm will have fallen. The experiments described here throw into serious doubt the evidence that has been used to conclude that tolerance is obligatorily MHC restricted.

Animals↗