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At least 595 records · Page 33Linked to original sources
PubMed1984

Cells in the pretectal olivary nucleus are in the pathway for the direct light reflex of the pupil in the rat.

Extracellular microelectrode recordings from 148 single cells in the pretectum of the hooded rat were classified according to their temporal response properties to light stimulation of their retinal receptive fields. Fifty-six cells were classified as tonic-on cells, 22 cells were classified as tonic-off cells, and 53 cells were classified as phasic cells. Seventeen cells could not be assigned to one of these 3 groups. The diameters of the receptive field centers of the tonic-on pretectal cell were clustered about a mean of 31 degrees and the temporal response of these cells was sustained. Constriction of the contralateral pupil was produced by electrical stimulation through the recording electrode at sites containing tonic-on pretectal cells, but not at sites containing tonic-off pretectal cells or phasic pretectal cells. For this reason, we argue that tonic-on cells are likely to mediate constriction in the light reflex of the rat's pupil. Receptive field maps together with electrolytic marking lesions at recording and stimulation sites showed that tonic-on pretectal cells are retinotopically organized and are aggregated in a strip running from the dorso-medial tip of the pretectum to the ventro-lateral boundary. The anatomical distribution of these cells is coextensive with the region known as the pretectal olivary nucleus (PO) in the rat. Using fine microelectrodes, recordings were obtained from 27 axons presumed to be of optic origin (fibers). Of these, 14 were tonic-on, 10 were phasic, 2 were tonic-off, and 2 were unclassified. Recordings from tonic-on fibers were obtained near tonic-on pretectal cells, typically in the most dorsal light-responsive region of the pretectum. These fibers were activated by single pulse electrical stimulation of the optic chiasm. The mean receptive field center diameter of 6 tonic-on fibers was 10.1 degrees, or about a factor of 3 less than that of pretectal tonic-on cells. The mean conduction velocity of 14 tonic-on fibers was 3.1 m/s. We argue that the tonic-on cells of the PO serve to integrate signals from tonic-on center retinal ganglion cells with adjacent receptive fields to provide signals for constriction of the pupil to neurons in the oculomotor nucleus.

Animals↗
PubMed1982

The incidence of the head louse (Pediculus humanus capitis) among pupils of two schools in Accra.

Of 319 pupils examined by visual inspection for head lice in two large schools of contrasting socioeconomic environments in Accra, Ghana, 158 were found to be infected, with infection rates being higher in the school of lower socio-economic status. Younger pupils (7 years) had significantly lower infection rates than older one (11 years). Hair plaiting, communal use of toilet facilities and crowding have been found to be involved in the epidemiology of the head louse. A curious discrepancy was found between the number of pupils who admitted they had lice and those who actually had them. Relative intensities of infestation remain very low in 75% of the cases examined. Mothers have been found to exhibit a high sense of responsibility in treating their children. A call has been extended to the Health Authorities to initiate a national delousing programme for the control of this ectoparasite.

Age Factors↗
PubMed1989

Computing high order wave aberration coefficients from variations of best focus for small artificial pupils.

Van den Brink (1962) measured the variation of best focus of vertical bar targets through a 1.4 mm aperture across the pupil of the eye. He expressed his results in contour maps of isodioptric lines across the pupil. The relative focus of a portion of the pupil is a function of the curvature of the wave front within the aperture. The curvature, in turn, is proportional to the second derivative of the wave aberration polynomial. Thus it is possible to make estimates of some of the coefficients of the wave aberration polynomial from Van den Brink's focusing data. This has been done for two states of accommodation. The results indicate that the wave aberration polynomial of the measured eye contains some significant terms of a power higher than hitherto measured.

Accommodation, Ocular↗
PubMed1995

Gender differences in pain ratings and pupil reactions to painful pressure stimuli.

In order to investigate gender differences in pain perception, the present study employed both a psychophysical and a psychophysiological measure. In experiment 1, 20 subjects rated the painfulness of 4 different levels of tonic pressure applied to their fingers using a verbally anchored categorization procedure. In general agreement with studies of pain threshold and tolerance, female subjects reported greater pain at high levels of stimulation, with no gender difference being evident at low pressure levels. In experiment 2, 16 different subjects were exposed to the same painful pressure stimuli while measuring their pupil reactions using infrared video pupillometry. The pupil dilations seen during the last 10 sec of the 20-sec pressure application turned out to be a highly significant indicator of pain intensity. When female and male subjects were compared on this measure, a similar divergent pattern as in the psychophysical data emerged, with female subjects showing greater pupil dilations at high pressure levels only. The fact that gender differences in pain perception can be demonstrated using an autonomic indicator of pain that is beyond voluntary control suggests that these differences reflect low-level sensory and/or affective components of pain rather than attitudinal or response-bias factors.

Female↗
PubMed1995

Anxiety of asthmatic pupils in Israel during the Persian Gulf War: treatment and counseling implications.

The aim was to study the increase in anxiety of asthmatic pupils during a state of war in comparison with healthy pupils. Twenty-five asthmatic adolescents completed Spielberger' STAI during three periods: (1) 4 months before the war; (2) during the second week of the war; and (3) 4 months after the end of the war. The comparison group included 54 healthy pupils visiting the same school. The results showed that the level of state and trait anxiety of the asthmatic and comparison group remained constant, without any significant increase, even during the war. The anxiety was not influenced by gender nor by socioeconomic level. It is concluded that during severe stressful events, there is no need for special medication for asthmatic patients.

Adolescent↗
PubMed2003

Pupil responses associated with coloured afterimages are mediated by the magno-cellular pathway.

Sustained fixation of a bright coloured stimulus will, on extinction of the stimulus and continued steady fixation, induce an afterimage whose colour is complementary to that of the initial stimulus; an effect thought to be caused by fatigue of cones and/or of cone-opponent processes to different colours. However, to date, very little is known about the specific pathway that causes the coloured afterimage. Using isoluminant coloured stimuli recent studies have shown that pupil constriction is induced by onset and offset of the stimulus, the latter being attributed specifically to the subsequent emergence of the coloured afterimage. The aim of the study was to investigate how the offset pupillary constriction is generated in terms of input signals from discrete functional elements of the magno- and/or parvo-cellular pathways, which are known principally to convey, respectively, luminance and colour signals. Changes in pupil size were monitored continuously by digital analysis of an infra-red image of the pupil while observers viewed isoluminant green pulsed, ramped or luminance masked stimuli presented on a computer monitor. It was found that the amplitude of the offset pupillary constriction decreases when a pulsed stimulus is replaced by a temporally ramped stimulus and is eliminated by a luminance mask. These findings indicate for the first time that pupillary constriction associated with a coloured afterimage is mediated by the magno-cellular pathway.

Afterimage↗
PubMed2002

Pupil-sparing third nerve palsy with preoperative improvement from a posterior communicating artery aneurysm.

BACKGROUND: Despite the plenitude of reports concerning partial or complete third nerve palsies, especially as presenting symptoms with posterior communicating artery (PCoA) aneurysms, we present a patient with an unusual variation. CASE DESCRIPTION: A 66-year-old woman presented with progressive right-sided headaches and diplopia and was found to have a partial, pupil-sparing third nerve palsy. A small right-sided PCoA aneurysm, nearly indistinguishable from an infundibulum, was identified on magnetic resonance angiography and subsequent digital subtraction angiography. The third nerve palsy improved before surgical repair of the aneurysm. RESULTS: Microsurgical exploration revealed a small PCoA aneurysm, which was tethered to the third nerve by arachnoid adhesions. Adhesions were lysed and the aneurysm was repaired sparing the PCoA and its branches. The patient's third nerve function recovered completely postoperatively. CONCLUSIONS: Even a very small PCoA aneurysm may present with an improving, pupil-sparing partial third nerve palsy. Selection of patients for imaging studies should take this unusual variant into consideration. We describe the anatomy and potential mechanisms of this pupil-sparing third nerve palsy.

Aged↗
PubMedDate not supplied

Pupil-led sex education in England (RIPPLE study): cluster-randomised intervention trial.

BACKGROUND: Improvement of sex education in schools is a key part of the UK government's strategy to reduce teenage pregnancy in England. We examined the effectiveness of one form of peer-led sex education in a school-based randomised trial of over 8000 pupils. METHODS: 29 schools were randomised to either peer-led sex education (intervention) or to continue their usual teacher-led sex education (control). In intervention schools, peer educators aged 16-17 years delivered three sessions of sex education to 13-14 year-old pupils from the same schools. Primary outcome was unprotected (without condom) first heterosexual intercourse by age 16 years. Analysis was by intention to treat. FINDINGS: By age 16 years, significantly fewer girls reported intercourse in the peer-led arm than in the control arm, but proportions were similar for boys. The proportions of pupils reporting unprotected first sex did not differ for girls (8.4% intervention vs 8.3% control) or for boys (6.2% vs 4.7%). Stratified estimates of the difference between arms were -0.4% (95% CI -3.7% to 2.8%, p=0.79) for girls and -1.4% (-4.4% to 1.6%, p=0.36) for boys. At follow-up (mean age 16.0 years [SD 0.32]), girls in the intervention arm reported fewer unintended pregnancies, although the difference was borderline (2.3% vs 3.3%, p=0.07). Girls and boys were more satisfied with peer-led than teacher-led sex education, but 57% of girls and 32% of boys wanted sex education in single-sex groups. INTERPRETATION: Peer-led sex education was effective in some ways, but broader strategies are needed to improve young people's sexual health. The role of single-sex sessions should be investigated further.

Adolescent↗
PubMed1989

Atonic pupil after cataract surgery.

A dilated, atonic pupil is a recognized but unusual complication of cataract surgery. It appears to be a more common occurrence than the paucity of previously published reports would suggest. In this article, seven cases of post-cataract extraction atonic pupil are described. All patients underwent uneventful cataract extraction with posterior chamber intraocular lens (IOL) implantation. In all except one patient, there was a delay from the time of surgery to the development of the atonic pupil. Pharmacologic testing demonstrated that the site of the lesion was the iris sphincter. Possible pathogenic mechanisms are discussed.

Aged↗
PubMed1999

Causes of hearing impairment in deaf pupils with a mental handicap.

An aetiological study was performed on 122 deaf pupils (57 aged < 20 years, 65 aged > 20 years) at the Institute for the Deaf in Sint-Michielsgestel, The Netherlands. Besides hearing impairment with thresholds of > 60 dB HL, all the participants had a mental handicap with a non-verbal IQ of 40-80. Sixteen per cent of them were of non-Dutch origin. The cause of hearing impairment was acquired in 48%, inherited in 17%, chromosomal in 4% and unknown in 30%. In comparison with other studies on the aetiology of childhood deafness, acquired causes predominated over inherited causes, which may be typical of deafness combined with a mental handicap. We found a significant predominance of non-Dutch pupils among the rubella aetiology cases and male predominance among the hearing impaired pupils in general.

Adolescent↗
PubMedDate not supplied

[Trends in tobacco, alcohol and cannabis consumption among secondary school pupils in Barcelona, Spain (1987-1999)].

OBJECTIVE: To describe trends in tobacco, alcohol, and cannabis consumption among secondary school pupils in Barcelona between 1987 and 1999. METHODS: Cross-sectional surveys administered to representative samples of pupils in the second year of secondary school between 1987 and 1999. The questionnaires were anonymous and self-completed. We present data from 5013 secondary school pupils from Barcelona who participated in one of the five surveys. RESULTS: Regular smoking (daily and weekly) showed a uniform decrease between 1987 and 1996. The results of the last survey (1999) showed an increase over those the 1996 survey, ranging from 13.4% for regular smoking to 38.7% for experimental smoking. Between 1987 and 1999, the percentage of schoolchildren who reported drinking at least half a glass of alcohol at some time showed an overall decrease of 14.0%. No differences in sex were found in problematic alcohol consumption, while a higher proportion of girls (14.0%) than boys (10.5%) reported getting drunk at some time. Whereas in 1996, 6.9% of the population studied had smoked cannabis at some time, in 1999 this proportion was 7.3%, with no differences between sexes. CONCLUSIONS: During the study period regular smoking increased, alcohol consumption decreased and cannabis consumption tended to level-off. Differences between boys and girls tended to disappear.

Adolescent↗
PubMed1992

Academic success of integrated hearing-impaired pupils who had enrolled in the early written-oral language program.

Data on academic success were analyzed for 37 hearing-impaired pupils who had been trained by the Written-Oral Language Method before school age. Seventy-one percent of pupils whose average hearing level was less than 89 dB and 77% of pupils whose hearing was 90 to 120 dB succeeded academically. Degree of hearing impairment, speech intelligibility, and gender were not important to their success. Linguistic competence evaluated just before enrollment in a normal educational setting at 6 years of age was the only factor significant to their academic success. However, we propose that the investigation of other factors, IQ and age at the start of preschool training program, must be analyzed in more detail in the future.

Child Language↗
PubMed2002

Calcium intake in relation to diet and health indicators in Cretan primary and high school pupils, Greece.

In recent years, the issue of dietary calcium (Ca) requirements is said to have caused more controversy than requirements for any other nutrient. There is little published data on dietary Ca intake levels in Greek children and relationships with other health indicators. Pupils at twenty primary and ten high schools in Crete, Greece, were examined as part of a wider study of the dietary habits and health status of children and adolescents. A total of 1054 children participated: 583 9- to 12-year-olds and 471 14- to 16-year-olds. "High" and "low" Ca intake in each age group was defined using upper and lower Ca intake quartiles for each sex. Multiple regression techniques were used to examine associations after adjustment for energy intake. No statistical association was observed between calcium intake and serum lipoproteins, anthropometric measurements, or physical activity status. Energy-adjusted Ca intakes were positively associated with intakes of protein, saturated fatty acid (SFA), magnesium, phosphorus, vitamin A, and vitamin B2, whereas higher Ca intakes were associated with lower monounsaturated fatty acid (MUFA) and omega-6 fatty acid intakes. In both age groups, pupils with high Ca intake had higher intakes of the food groups "milk and milk products" and "grains and grain products" than those with low Ca intake, although even "high" Ca intake in older female Cretan pupils (with a 75th percentile cut-off of 999 mg/day) may not be at adequate levels.

Adolescent↗
PubMed1998

'D-shaped' and 'reverse-D-shaped' pupil in a cat with lymphosarcoma.

A 7-year-old female spayed European shorthair cat was presented because of visual reduction and a green reflex in the right eye. Examination revealed a 'D-shaped' pupil in the right eye and a 'reverse-D-shaped' pupil in the left eye. Both eyes showed fibrinous anterior uveitis with exudates in the anterior chamber and precipitates on the posterior surface of the cornea. In both eyes a chorioretinitis was diagnosed which caused partial retinal detachment and peripapillary oedema in the left eye. Histopathology revealed intestinal and ocular lymphosarcoma. The aberrant pupil shapes which persisted after death were due to infiltration of the iris stroma and were not caused neurologically. The observation that in both eyes only the medial parts of the iris were affected could not be explained.

Journal Article↗
PubMed2003

The streak retinoscopy pupil reflex in the presence of astigmatism.

Computer simulation is being increasingly used as a teaching tool. Having developed a computer-generated virtual focimeter, we are now in the process of developing a computer-generated virtual streak retinoscope to teach the principles of retinoscopy and the effect of residual refractive error and mirror movement on the pupil reflex. One of the important requirements was to provide as accurate a simulation as possible for the completely general case of an astigmatic patient and a streak in any orientation being moved also in any orientation. This required a thorough understanding of the optical theory of the retinoscope and equations that describe the behaviour of the pupil reflex. We have taken this opportunity to review the optics of the streak retinoscope and derive equations for the behaviour of the pupil streak reflex.

Astigmatism↗
PubMed1989

Self-, ingroup, and outgroup achievement attributions of German and Turkish pupils.

The present study investigated intergroup bias in achievement attributions in a sample of 62 German and 55 Turkish pupils (aged 15 years) in the Federal Republic of Germany. The design was 2 x 2 x 2 x 3 (Ethnic Group x Outgroup Prejudice x Outcome x Stimulus) with repeated measures on the last two factors. Subjects attributed examination performance to ability, effort, luck, and task difficulty. Intergroup bias was limited to German pupils, who attributed failure of an ingroup member or self more to bad luck than they did that of an outgroup member. Turkish pupils acted more in terms of self than ingroup, attributing the success of another Turkish child more to good luck than they did that of self or an outgroup member. They also failed to distinguish clearly between success and failure in their task attributions. Results are discussed in terms of the inventive nature of explanations for ability-linked performance and the motivational consequences of causal attributions.

Achievement↗
PubMed1991

Teachers' conceptualization of pupil control in elementary school physical education.

Management of conduct has been considered the most important problem facing schools in America during 16 of the last 20 years (Gallup, 1988). Yet little is known about specific techniques teachers use to achieve pupil control in physical education. One purpose of this work is to describe the development of a conceptual framework for pupil control techniques. The framework was derived from 64 live observations and audiotapes of elementary school physical education lessons. A second purpose is to describe how teachers may potentially foster pupil self-control. Data were reduced through analytic induction, constant comparison, and topological analysis. The investigator placed 23 categories into three classifications as perceived by teachers: anticipatory, tutorial, and punitive. Teachers confirmed frequency of using techniques during interviews and on surveys. Intraobserver agreement tests yielded 88% for distinguishing among categories. Interobserver scores ranged from 83 to 86% agreement. Categories may serve to increase teachers' repertoire of control techniques in accordance with their ideological beliefs. For teachers in this study, facilitating self-control involves (a) selecting tutorial control techniques, (b) using indirect forms of techniques, and (c) conveying reasons for using techniques.

Adult↗
PubMed1992

School-based theories of pupil assessment: a case study.

Case study design was used in this investigation of the pupil assessment theories of two middle school physical education teachers whose program was identified as a good program in which pupil assessment was taking place. An assumption guiding the study was that teachers' actions are rational and are designed to produce desired results. Therefore, a comparison is made only between two theories of action (espoused and enacted) rather than between theory and practice. Informal and semistructured interviews were employed to elicit teachers' espoused theories, and enacted theories were identified during field visits over a semester in which classes were observed and school documents examined. Teachers' theories of assessment are identified for the categories of participation, effort, and improvement; grading; written tests; fitness testing; performance tests; and formative recordkeeping. Espoused and enacted theories are then examined for congruency. The highest level of incongruency was found in the areas of performance tests and formative recordkeeping. Barriers to the use of pupil assessment techniques in this program include organizational, knowledge, and contextual factors. Change in the assessment practices of secondary teachers may be facilitated, however, through the identification and examination of teachers' theories of assessment by both preservice and inservice teachers.

Case-Control Studies↗