PubMed Health⌕ Search

Biomedical subjects

R Epstein

Publications and source records attributed to R Epstein.

At least 37 records · Page 2Linked to original sources
PubMed1999

Sleep patterns in autistic children.

Sleep disturbances are regarded as a common clinical feature in autistic children. This concept is based primarily on informal observations or studies conducted with questionnaires. In this study we compared data obtained by questionnaires to that obtained with actigraphy. Among 22 autistic children, 12 were reported as having sleep problems and 8 patients completed 72 hours actigraphy. While the employment of questionnaires disclosed that autistic children had an earlier morning awakening time and multiple and early night arousals, actigraphic monitoring showed that with the exception of an earlier morning arousal time (p = .045), sleep patterns of autistic children were similar to that of normal children. Parental oversensitivity to sleep disturbances of the autistic children may explain this phenomenon.

Autistic Disorder↗
PubMed1999

Repetition blindness for locations: evidence for automatic spatial coding in an RSVP task.

The authors report a new phenomenon called repetition blindness (RB) for locations: When 3 or 4 letters are presented rapidly and sequentially at random locations within a spatial array, experimental participants have difficulty reporting pairs of letters appearing in the same location within 250 ms of each other. This deficit occurs both during report of letter identities and during report of the locations in which the letters appear; it can also be found using a partial report task. During letter report, the deficit is found for 4-location arrays but not for 8-location arrays. In contrast, letter RB is not found during location report even when the letters are always chosen from a set of 4. These results indicate that a small number of locations--but not letters--can be encoded automatically even when they are not explicitly reported. The authors argue that RB for locations results from a difficulty individuating 2 tokens at the same spatial location.

Adult↗
PubMed1998

Starting times of school: effects on daytime functioning of fifth-grade children in Israel.

In the present study we investigated the effects of school starting time on daytime behavior and sleep. Eight-hundred and eleven 5th grade pupils (10-12 years old) from 28 classes in 18 schools throughout Israel were divided into "early risers" (N = 232) who started school at 07:10 (42%) at least 2 times a week, and "regular risers" (N = 340) who always started school at 08:00 (58%). The remaining 239 pupils started school between 7:20 and 07:55 (and also after 08:00), and were not included in the study. Self-administered questionnaires concerning sleep habits during school days, weekends, and holidays, daytime fatigue, sleepiness, and difficulties concentrating and paying attention in school were completed by all children. Mean sleep time of the "early risers" was significantly shorter than that of the "regular risers." Early risers complained significantly more about daytime fatigue and sleepiness, and about attention and concentration difficulties in school. Their complaints were independent of the reported hours of sleep. We conclude that early starting of school negatively affects total sleep time and, as a consequence, has a negative effect on daytime behavior. The implications of these findings to the ongoing controversy concerning sleep need in contemporary society are discussed.

Adolescent↗
PubMed1998

A cortical representation of the local visual environment.

Medial temporal brain regions such as the hippocampal formation and parahippocampal cortex have been generally implicated in navigation and visual memory. However, the specific function of each of these regions is not yet clear. Here we present evidence that a particular area within human parahippocampal cortex is involved in a critical component of navigation: perceiving the local visual environment. This region, which we name the 'parahippocampal place area' (PPA), responds selectively and automatically in functional magnetic resonance imaging (fMRI) to passively viewed scenes, but only weakly to single objects and not at all to faces. The critical factor for this activation appears to be the presence in the stimulus of information about the layout of local space. The response in the PPA to scenes with spatial layout but no discrete objects (empty rooms) is as strong as the response to complex meaningful scenes containing multiple objects (the same rooms furnished) and over twice as strong as the response to arrays of multiple objects without three-dimensional spatial context (the furniture from these rooms on a blank background). This response is reduced if the surfaces in the scene are rearranged so that they no longer define a coherent space. We propose that the PPA represents places by encoding the geometry of the local environment.

Brain Mapping↗
PubMed1997

Popularity of less frequent follow up for breast cancer in randomised study: initial findings from the hotline study.

OBJECTIVE: To compare the experiences of patients with breast cancer who were conventionally monitored with those in whom routine follow up was restricted to the time of mammography. DESIGN: Randomisation to conventional schedule of clinic visits or to visits only after mammography. Both cohorts received identical mammography and were invited to telephone for immediate appointments if they detected symptoms. SETTING: Combined breast clinic, Chelsea and Westminster Hospital. SUBJECTS: 211 eligible outpatients with a history of breast cancer. MAIN OUTCOME MEASURES: Acceptability of randomisation, interim use of telephone and general practitioner, satisfaction with allocation to follow up. RESULTS: Of 211 eligible patients, 196 (93%) opted for randomisation in the study. Of these, 55 were under 50 years, 78 were diagnosed fewer than five years before, 90 had stage T2-4 tumours, and 71 had involved axillary nodes. Patients who did not participate were more likely to be under 50 years, to be two to five years after diagnosis, and to have had aggressive primary disease. Twice as many patients in both groups expressed a preference for reducing rather than increasing follow up. No increased use of local practitioner services or telephone triage was apparent in the cohort randomised to less frequent follow up by specialists. CONCLUSIONS: Reducing the frequency of routine follow up has so far proved popular among patients with breast cancer at standard risk in this cohort. A multicentre study is needed to determine the effectiveness and cost-effectiveness of routine follow up with respect to disease outcomes.

Adult↗
PubMed1997

Dichotic listening in children: the reflection of verbal and attentional changes with age.

A sample of 290 kindergarten children (147 girls), all native Hebrew speakers, were tested by two dichotic listening tests: (a) a digits test (low verbal workload) and (b) a words test (high verbal workload). The same subjects were tested one year later (at the end of their first year at school) by the same tests. In both tests and both testing sessions the free recall procedure was used. It was found that the performance difference between ears significantly decreased and overall performance significantly increased in the digits test in the second testing session. Differences between sessions in ear difference in the words test were not significant, although overall performance in the second session increased. These data lend support to the hypothesis that the change with age in the between-ears difference is mainly related to an improvement in verbal processing efficiency, which in turn allows the allocation of more verbal resources to the inferior input channel, without a decrease in resources allocated to the preferred one. As expected, increase in available verbal resources was clearly manifested under low verbal workload conditions but not under high workload conditions, where task demands did not allow significant increase in verbal resources to be allocated to the inferior channel. This hypothesis also predicted highly consistent ear preference owing to its being solely determined by the verbal processors of the dominant-to-speech hemisphere. The inconsistent ear preference between tests found in more than a third of the subjects of this sample could not therefore be accounted for by the stated hypothesis. The analysis of performance in subjects who showed left-ear preference in only one test and right-ear advantage on the other occasions indicated that whenever the left ear was preferred it was accompanied by significantly smaller ear difference and lower overall performance compared with those manifested by the same subjects in the same test in the other testing session. These data are better accounted for by the hypothesis that two different pools of resources are involved in splitting attention between ears in the free recall of dichotically presented verbal stimuli: one which is controlled by verbal processors of the dominant-to-speech hemisphere and the other by a spatial attentional mechanism. However, it seems that changes in dichotic test performance within the first year at school can mainly be attributed to increase in verbal resources rather than to improvement in allocation of spatially controlled resources.

Age Factors↗
PubMed1997

The economic cost of hip fractures in community-dwelling older adults: a prospective study.

OBJECTIVES: To evaluate the incremental cost in the year after hip fracture. DESIGN: Prospective cohort study. SETTING: Baltimore, Maryland. PARTICIPANTS: 759 community dwelling older patients who sustained a hip fracture and participated in the Baltimore Hip Fracture Study. MEASUREMENTS: Resource use for direct medical care, formal nonmedical care, and informal care in the 6 months before and the year after fracture was estimated from interviews with patients or proxy respondents. Costs in 1993 dollars were estimated by multiplying resources times national unit cost estimates. RESULTS: The annualized costs in the year before the fracture ranged between $18,523 and $20,928. The costs in the year after the fracture equaled $37,250. The incremental costs in the year after the fracture, compared with the costs in the year before the fracture, ranged between $16,322 and $18,727. The largest cost differences were attributable to hospitalizations, nursing home stays, and rehabilitation services. CONCLUSIONS: Because we compared the costs after a fracture with costs before, our estimates of the incremental cost of a hip fracture are lower than others in the literature. These results, obtained from interviews with patients enrolled in a cohort study, or their proxies, provide the best data available to date on the economic cost of hip fractures among community-dwelling older persons.

Aged↗
PubMed1997

The short-term impact of Botox injections on speech disability in adductor spasmodic dysphonia.

This study investigates the impact of Botox injections on speech disability in a group of patients with adductor spasmodic dysphonia. Patient-perceived disability was assessed on the Speech Disability Questionnaire. A factor analysis on speech disability yielded five factors. Four of these, social isolation (p < 0.001), negative communication (p < 0.005), public avoidance (p < 0.05) and limited understanding (p < 0.01), showed significant change from prior to and one week post injection. Speech and language therapists' assessment also showed changes in voice quality over the same period. These findings are discussed in terms of the relationship between voice quality, disability and handicap, in adductor spasmodic dysphonia.

Adult↗
PubMed1997

Changing from communal to familial sleep arrangement in the Kibbutz: effects on sleep quality.

Sleep was actigraphically investigated in 27 Kibbutz children while sleeping in communal sleeping houses, and 1 year after changing to familial sleeping arrangements. Three independent control groups of city-living children were also recorded. Two of them were age-comparable, and the third control group was included in order to examine possible effects of the Gulf War on the communal sleep group. The results showed that the sleep quality of Kibbutz children improved significantly after moving to familial sleep. Comparison with the data from the two control groups revealed a greater resemblance between sleep of the Kibbutz children after moving to live with their families and that of the city-living children. Comparing the sleep of the children in communal sleep to that of the additional group of children examined during the Gulf War strengthened the above results, i.e. the communal sleep group that was investigated before the war slept worse than the control children that were investigated during the war. After discarding developmental and physical condition-related changes, it was concluded that the improvement in sleep quality was due to the children's increased sense of security when sleeping with their families.

Child, Preschool↗
PubMed1996

Human cancer cells exhibit protein kinase C-dependent c-erbB-2 transmodulation that correlates with phosphatase sensitivity and kinase activity.

The c-erbB-2 receptor tyrosine kinase is often overexpressed in human tumors, but the functional implications of this phenotype remain unclear. We previously used phosphorylation-specific antibodies to define major differences in c-erbB-2 tyrosine kinase activity between overexpressing human tumor cell lines (Epstein, R. J., Druker, B. J., Roberts, T. M., and Stiles, C. D. (1992) Proc. Natl. Acad. Sci. U. S. A. 89, 10435-10439). Here we extend this approach to define the relationship between c-erbB-2 tyrosine phosphorylation and protein kinase C (PKC)-dependent transmodulation. Phosphorylation-specific antibodies to the juxtamembrane PKC site Thr686 recognize tyrosine-dephosphorylated wild-type c-erbB-2 following G8/DHFR 3T3 cell treatment with PKC agonists. B104-1-1 cells transformed by activated c-erbB-2 express a subset of tyrosine-phosphorylated receptors that are homologously phosphorylated on Thr686, indicating that Thr686 phosphorylation alone is insufficient to abrogate receptor tyrosine phosphorylation. Similarly, the c-erbB-2-overexpressing human cancer cell lines SK-Ov-3 and BT-474 express constitutively Thr686-phosphorylated receptors. SK-Ov-3 cells express predominantly kinase-inactive c-erbB-2 that is heavily Thr686-phosphorylated, indicating that Thr686 phosphorylation in this line is heterologous in origin. In contrast, BT-474 cells express constitutively autophosphorylated c-erbB-2 despite Thr686 phosphorylation. These results indicate that Thr686 phosphorylation does not directly abolish c-erbB-2 activity and suggest that such phosphorylation reflects constitutive PKC activity induced by either receptor-activating mutations or heterologous growth factors. The latter possibility suggests in turn that c-erbB-2 interacts in an as yet undefined way with heterologous growth factor receptors in human tumor cells.

Animals↗