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Biomedical subjects

C Kennard

Publications and source records attributed to C Kennard.

At least 127 records · Page 7Linked to original sources
PubMed1985

Rapid fading of visual sensations in a subject with a parietal-occipital tumour.

We present psychophysical data measured for a single subject, who had a tumour in the left parieto-occipital region, located by CT scan and post-mortem study. Her vision was characterised by rapid fading during voluntary fixation of images located in the right hemifield. We describe a number of simple tests which we developed in order to study this phenomenon. The results of these tests established that significant loss of function occurs within 1 s of fixation and that the effects associated with fixation are spatially localised. We compare our subject's response characteristics with those observed in other cases of visual disturbance and we examine the possible underlying mechanisms which give rise to the rapid fading of her visual images.

Adult↗
PubMed1983

A new ambulatory monitoring system for tremor.

We have described a fully portable tremor recording system which allows a patient to carry out his normal day's activities with minimal hindrance. Computer analysis of the recording has enabled the extent of the tremor over prolonged periods to be presented in a format which is easily understandable and which should be useful for the objective assessment of therapy.

Ambulatory Care↗
PubMed1982

Treatment of the Guillain-Barré syndrome by plasma exchange.

Twelve consecutive patients with Guillain-Barré syndrome were treated with plasma exchange. Examination two weeks after treatment was commenced showed that three had not improved. Five showed only a minimal improvement, which was considered to be compatible with the natural history of the disease. The remaining four patients showed a more substantial improvement which could have been related to the plasma exchange.

Adult↗
PubMed1982

Evoked potentials in the evaluation of visual field defects due to chiasmal or retrochiasmal lesions.

We used monocular full-field and hemifield pattern reversal stimulation to study visual evoked potentials (VEPs) in 20 patients with confirmed defects of the visual pathways. In 10 of 12 patients with homonymous field defects, it was possible to lateralize the brain lesion but not to predict the site of the lesion within the hemisphere. In four of eight patients with bitemporal field defects, VEPs suggested involvement at the chiasmal level. In the remaining cases, VEPs provided no correlation with perimetric and radiologic findings. We found that VEPs usually corroborated other diagnostic studies but subtle defects were not detected reliably, and large hemianopic defects were occasionally not lateralized accurately. VEP analysis is therefore of only limited value in assessment for clinical purposes of patients with homonymous or bitemporal hemianopias.

Adolescent↗
PubMed1981

Hand wasting in spondylotic high cord compression: an electromyographic study.

Conventional and single-fiber electromyographic studies in two patients with a wasted hand associated with spondylotic narrowing of the spinal canal at C3-4 and C5-6 revealed changes that were most severe in the hand muscles (C8, T1) and moderately severe in the extensor digitorum communis (C7), but relatively spared the C5 and C6 myotomes. This gradation of abnormality within the cervical cord is consistent with stagnant hypoxia secondary to venous congestion.

Aged↗
PubMed1981

Acute viral encephalitis: its diagnosis and outcome.

Sixty patients with acute viral encephalitis admitted to The London Hospital in the last fifteen years have been reviewed. These consisted of 12 patients with known viral infection, 29 patients with acute viral infection of undetermined type, and 19 patients in whom an encephalitic illness followed a viral infection (post-infection encephalitis). The patients with primary viral encephalitis presented with an inflammatory brain disorder, including headaches and fever, and developed focal or diffuse neurological signs. Patients with post-infection encephalitis, usually following a 'flu'-like illness, presented with an acute neurological disturbance. The results of investigations, including virological studies, CSF examination, electroencephalography and neuroradiology, are described. Biopsy or autopsy material was available in 11 patients and these pathological findings supported the clinical classification of these patients. The mortality was highest in patients with herpes simplex virus encephalitis and lowest in patients with post-infection encephalitis. A considerable morbidity was found, not only in patients with primary viral encephalitis, but also in patients with encephalitis of unknown aetiology and post-infection encephalitis.

Acute Disease↗
PubMed1981

The association of periodic alternating nystagmus with periodic alternating gaze. A case report.

A 26-year-old man with a recurrent cerebellar medulloblastoma developed periodic alternating nystagmus. During radiation treatment, a bilateral voluntary horizontal gaze paresis appeared, and the periodic alternating nystagmus was replaced by periodic alternating gaze. Several days later, full eye movements returned, as did the periodic alternating nystagmus which had an identical periodicity to the periodic alternating gaze. The underlying pathophysiology of periodic alternating nystagmus and periodic alternating gaze is discussed.

Adult↗
PubMed1981

Factors involved in the development of ipsilateral retinothalamic projections in Xenopus laevis.

The extent, and the development, of the ipsilateral retinothalamic projection in the frog Xenopus laevis have been studied using terminal degeneration and autoradiographic techniques. This ipsilateral projection derives only from those retinal areas receiving visual information from the binocular portion of the visual field. In Xenopus, the ipsilateral retinothalamic projection arises from a larger area of the retina than was found to be the case in earlier studies on Rana. This correlates with the fact that Xenopus has a larger binocular visual field than does Rana. The ipsilateral retinothalamic projection is just detectable at about stage 56 of larval life, considerably later than its contralateral counterpart. Experimental manipulation of the developing eye vesicle at early larval stages followed by histological studies of the ipsilateral retinothalamic projections showed, however, that the retinal areas which give rise to this projection are determined by stage 32 of larval life. Further studies, in which monocular enucleation was performed at different larval stages with subsequent examination of the retinothalamic projections from the remaining eye, indicated that the selective pattern of decussation and non-decussation of retinothalamic fibres at the optic chiasma does not require interactions, at the chiasma, between optic fibres from the two eyes.

Animals↗
PubMed1980

Effect of lecithin on disability and plasma free-choline levels in Friedreich's ataxia.

Four patients with Friedreich's ataxia took part in an open trial, in which they consumed 50-100g/day lecithin granules (containing approximately 22% phosphatidycholine) for 16 weeks, but no improvement resulted. Several unwanted effects including diarrhoea, nausea, depression, "hot flushes" and weakness were experienced. Resting levels of free-choline in plasma were within the range found in 19 normal subjects. Sixteen other patients with Friedreich's ataxia also had normal free-choline levels. Treatment with lecithin significantly increased plasma free-choline levels, but there was a trend for these to fall towards baseline levels, despite continued ingestion of lecithin.

Adolescent↗
PubMed1979

Infection of the brainstem by Listeria monocytogenes.

A case of brainstem infection by Listeria monocytogenes is described. The patient was a 63 year old man previously in good health and his illness did not follow the usual bi-phasic pattern. There was no prodromal phase, and the progressive brainstem signs with a lymphocytosis and a normal sugar level in the CSF led to a tentative diagnosis of viral brainstem encephalitis. Ampicillin was begun only when signs of pulmonary infection developed. Clinical diagnosis is difficult but ampicillin should probably be used in any doubtful case in which a "viral" brainstem encephalitis is being considered.

Brain Abscess↗
PubMed1978

Abnormalities of renal transport of sodium o-[131I]iodohippurate (Hippuran) in essential hypertension.

1. Renal function has been studied in 312 hypertensive patients by quantitative renography with sodium o-[131I]iodohippurate (131I-labelled Hippuran) and estimation of overall effective renal plasma flow. In 59% of the patients the results were normal. 2. Severe hypertension was associated not only with reduced effective renal plasma flow but also a characteristic abnormality of Hippuran transport in 10% of the patients in which there was a wider than normal variation in transit times of Hippuran through the kidney, which may reflect non-uniformity of reabsorption of filtrate by different groups of nephrons. 3. Plasma renin activity was higher in a group of 14 patients with multimodal transit time spectra than in a matched hypertensive control group, with very substantial overlap between the two groups. 4. The renographic abnormality was usually reversed by treatment.

Blood Flow Velocity↗
PubMed1978

Black pigment stone in a male child aged two years and seven months.

A case of cholelithiasis is reported occurring in a boy aged two years and seven months. The patient presented with biliary colic, and cholecystectomy was performed. Detailed analysis of the stone, including electron-probe studies, showed it to be an example of a polybilirubinate stone, containing also calcium, carbonate, and phosphate, with some sulphur, sodium, and magnesium. There were also traces of chlorine, aluminium, copper, nickel, and manganese.

Child, Preschool↗