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Biomedical subjects

H E Persson

Publications and source records attributed to H E Persson.

At least 37 records · Page 2Linked to original sources
PubMed1984

Oscillatory potentials, flash and pattern-reversal electroretinograms in amblyopia.

Oscillatory potentials (OP), flash and pattern-reversal electroretinograms (ERG) were recorded in 8 adult patients with amblyopia (visual acuity 0.3 or less) and 10 age-matched normal controls. No significant differences were observed in OPs between amblyopic and opposite eyes and normal controls. The pattern-reversal ERGs were significantly reduced in all amblyopic eyes. No significant side difference was found in the flash ERGs. The observed amplitude reduction in the pattern-reversal ERG might reflect dysfunction of the retinal ganglion cells, which have been supposed to be the main source of this type of ERG. No electrophysiological evidence could be demonstrated for a disturbed retinal function prior to the ganglion cell level.

Adult↗
PubMed1984

Pattern-reversal electroretinograms and visual evoked cortical potentials in multiple sclerosis.

Pattern-reversal and flash electroretinograms (ERG) and visual evoked cortical potentials (VECP) were recorded from 15 patients with definite multiple sclerosis (MS). All patients had prolonged VECP latency, indicating demyelination of one or both optic nerves. The pattern-reversal ERG amplitude was reduced below the level of normal variation (mean -2 SD) in 11 of the 22 eyes with prolonged VECP latency and in one of the eight eyes with normal VECP latency. The mean pattern-reversal ERG amplitude from eyes with prolonged VECP latencies was significantly lower than the mean amplitude from the normal controls. No abnormalities were observed in the flash ERGs. Degeneration of retinal ganglion cell axons has been demonstrated in MS patients. The amplitude reduction in the pattern-reversal ERG, observed in some 50% of the eyes with prolonged VECP latencies, is supposed to reflect retinal ganglion cell dysfunction or degeneration secondary to demyelination of the optic nerve.

Adult↗
PubMed1983

Pattern-reversal electroretinograms in unilateral glaucoma.

Pattern-reversal and flash electroretinograms (ERG) and oscillatory potentials (OP) were recorded from 11 patients with unilateral glaucoma. All glaucomatous eyes had reduced amplitudes both compared to the opposite eye in the same patient and to reference values. In 10 of the 11 cases this reduction was below the level of normal variation. The difference in pattern-reversal ERG amplitude means from glaucomatous and opposite eyes was statistically significant. No differences were observed in flash ERGs or OPs. The histopathologic correlate to the visual field defects in glaucoma is retinal ganglion cell degeneration. The present electrophysiologic findings support the view, based on results from animal experiments, that the pattern-reversal ERG reflects ganglion cell activity.

Aged↗
PubMed1982

Pattern-reversal electroretinograms in squint amblyopia, artificial anisometropia and simulated eccentric fixation.

Pattern-reversal electroretinograms were recorded in 10 normals and 10 adult patients with squint amblyopia (visual acuity 0.3 or less). The effects of artificial anisometropia and simulated eccentric fixation were tested in normals. The pattern-reversal ERG amplitude was reduced linearly with increased defocusing (0 to + 3 D). A significant amplitude reduction was observed when defocusing amounted to + 1 D. The amplitudes were not reduced below the range of normal variability at 4 degrees of simulated eccentric fixation. In the amblyopia patients, refractive errors were corrected. None had eccentric fixation of more than 4 degrees. Yet, the pattern-reversal ERGs were lower in the amblyopic eyes compared with the opposite normal eyes. The difference in amplitude means was statistically significant. The finding supports the view that retinal function is impaired in human squint amblyopia.

Adolescent↗
PubMed1982

Menstruation-related periodic hypersomnia: a case study with successful treatment.

A 16-year-old girl suffered from 1 to 2-week periods of hypersomnia associated with each menstruation. Serum hormone levels were normal. CSF concentrations of homovanillic acid and 5-hydroxyindolacetic acid were lower in hypersomniac than in symptom-free phases. 3-methoxy-4-hydroxyphenylethylene glycol was not affected. The sleep periods occurred only in connection with ovulatory menstrual cycles. When ovulation was inhibited by a combination of ethinylestradiol and lynestrenol, an oral contraceptive pill, the hypersomnia ceased. Thus, the hypersomnia seemed to be linked to the occurrence of ovulatory menstruations.

Adolescent↗
PubMed1980

Visual evoked responses to pattern-reversal stimulation in childhood amblyopia.

Visual evoked responses to monocular and binocular pattern-reversal stimulation were recorded in ten normal and twenty-three amblyopic children. In twenty of the twenty-three children with amblyopia the responses were found to differ from those in the normal group in one or several of the following parameters: side difference of amplitude, side difference of latency, amplitude increase to binocular stimulation. The described method can be of value as an aid in diagnosis of amblyopia.

Amblyopia↗
PubMed1980

Exposure to organic solvents. A cross-sectional epidemiologic investigation on occupationally exposed care and industrial spray painters with special reference to the nervous system.

In the present epidemiologic study 80 car or industrial spray painters with long-term low level exposure to organic solvents were examined and compared with two matched reference groups of nonexposed industrial workers (80 persons in each group). The aim of the study was to investigate the possible effects of the solvent exposure on health. The investigation included psychiatric interviews, psychometric tests, neurological, neurophysiological and ophthalmologic examinations, and computed tomography of the brain. The painters' previous and present exposure was carefully assessed by interviews and on-the-job measurements both at modern places of work and in a reconstructed model of a workshop from 1955. On the basis of the psychiatric interviews the psychiatric symptoms were rated according to a specially designed scale of 46 different items, graded in seven steps of increasing severity. The psychological performance was assessed by a battery of 18 tests. The neurological and neurophysiological examinations comprised visual evoked responses (VER), electroencephalography (EEG), and computerized EEG analysis (SPA) for the central nervous system and electroneurography (ENeG), the estimation of vibration sense thresholds, and a quantified neurological examination for the peripheral nervous system. The ophthamologic examination concentrated on the condition of the lens. Statistically significant differences between the exposed individuals and referents were found for psychiatric items indicative of a slight cerebral lesion (ie, a neurasthenic syndrome). The psychometric tests revealed statistically significant differences between the groups with respect to reaction time, manual dexterity, perceptual speed, and short-term memory. No differences were found with respect to performance on verbal, spatial, and reasoning tests. Significant differences between the groups were also found for the majority of the neurophysiological parameters measuring peripheral nerve functions, the most pronounced occurring in the long, sensory fibers. Moreover EEG and VER showed some differences between the groups, as did the results of the ophthalmologic examination and the computed tomography. Finally, it should be emphasized that the exposure levels, as measured at modern places of work and in the reconstructed workshop from 1955, were found to be considerably lower than the valid threshold limit values in Sweden.

Brain↗
PubMed1978

Provoked visual impairment in multiple sclerosis studied by visual evoked responses.

Pattern-reversal VERs were studied during the visual impairment provoked by exercise in 2 patients with demyelinating optic neuritis. It was found that the transient reduction in visual acuity was correlated to a transient decrease in the amplitude of the major positive component of the VER, whereas no significant changes could be observed in the latency of the response. The normal VER was not influenced by exercise.

Adult↗
PubMed1978

Long-term exposure to jet fuel. II. A cross-sectional epidemiologic investigation on occupationally exposed industrial workers with special reference to the nervous system.

Thirty jet fuel exposed workers selected according to exposure criteria and thirty nonexposed controls from a jet motor factory were examined, with special reference to the nervous system, by occupational hygiene physicians, psychiatrists, psychologists, and neurophysiologists. The controls and the exposed subjects were matched with respect to age, employment duration, and education. Among the exposed subjects the mean exposure duration was 17 years, and 300 mg/m3 was calculated as a rough time-weighted average exposure level. The investigation revealed significant differences between the exposed and nonexposed groups for (a) incidence and prevalence of psychiatric symptoms, (b) psychological tests with the load on attention and sensorimotor speed and (c) electroencephalograms. When the control group was selected, it was ensured that the two groups were essentially equivalent except for exposure to jet fuel. It is concluded, therefore, that the differences found between the groups are probably related to exposure to jet fuel.

Adult↗
PubMed1977

Changes in ultrastructure and function of the sheep pigment epithelium and retina induced by sodium iodate. I. The ultrastructure of the normal pigment epithelium of the sheep.

The normal ultrastructure of the sheep pigment epithelial cells is described as a basis for the interpretation of toxic (sodium iodate) effects on these cells dealt with in two following papers. The morphological features of the different cell membranes and cell organelles, particularly the phagosomes and the lipid droplets, are discussed in relation to renewal of the photoreceptor outer segment, pigment epithelial and retinal metabolism, barrier mechanisms and electrical properties.

Animals↗
PubMed1977

Changes in ultrastructure and function of the sheep pigment epithelium and retina induced by sodium iodate. II. Early effects.

The present investigation shows that the membrane properties of the sheep pigment epithelial cells were very rapidly and severely affected by sodium iodate, whereas the effects concerning the neuroretina were delayed. The c-wave of the ERG was immediately abolished and replaced by a cornea-negative potential, but the a- and b-waves were preserved for about 80-100 min. Ultrastructurally the plasma membranes (particularly the basal plasma membrane) of the pigment epithelial cells were destroyed or less distinct than normally. The cell organelles were swollen and ruptured. There were indications that the pigment epithelium could no longer participate in the receptor outer segment turnover. The photoreceptor cells were morphologically undamaged, and few or no signs of injury were observed in the inner layers of the retina. The effects upon the neuroretinal functions seen after 80-100 min, consisting of a reduction of alpha- and beta-wave amplitudes, were most likely caused by an inability of the pigment epithelium to maintain in the long run its metabolic and barrier properties. It appears that at an early stage after sodium iodate injection, the present preparation may be useful for the study of the effects on the neuroretina proper of drugs and other agents.

Animals↗
PubMed1976

Long-term exposure to jet fuel: an investigation on occupationally exposed workers with special reference to the nervous system.

In the present study the results of a neurological and neurophysiological health examination of 29 aircraft factory workers chronically exposed to jet fuel vapors are presented. The exposed subjects were classified into a heavily exposed and a less heavily exposed group. The examination included a standardized clinical neurological examination, measurements of the conduction velocities in the peripheral nerves, and threshold determinations of vibratory sensations in the extremities. All 13 persons examined in the heavily exposed group and 7 of the 16 in the less heavily exposed group stated that they had repeatedly experienced acute effects (dizziness, respiratory tract symptoms, heart palpitations, a feeling of pressure on the chest, nausea, headache) of the jet fuel vapors in the inhaled air. A high rate of symptoms indicative of neurasthenia and psychasthenia and symptoms and signs indicative of polyneuropathy was observed both in the heavily exposed group and in the two groups combined in comparison with reference groups. Considering the presented facts concerning (a) the acute effects on repeated occasions, (b) the high rates of symptoms indicative of neurasthenia and psychasthenia and symptoms and signs indicative of polyneuropathy, and (c) the differences in the observations made between the two groups with varying degrees of exposure to jet fuel, the authors interpreted the results as indicative of a possible effect of long-term exposure to jet fuel on the nervous system.

Environmental Exposure↗