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Biomedical subjects

M J Harrison

Publications and source records attributed to M J Harrison.

At least 235 records · Page 13Linked to original sources
PubMed1984

Evaluation of screening tests for detecting sacral autonomic neuropathy in diabetes mellitus. A preliminary study.

In 6 patients with diabetes mellitus and 6 non-diabetic "controls" referred for urological assessment, sacral electromyelography (SER) and electrical stimulation of the anal reflex were compared with pressure/flow videocystourethrography (VCU) for the detection of sacral neuropathy, whilst electrocardiography (ECG) was used to screen for generalised autonomic neuropathy. Five diabetics had evidence of a neuropathic bladder on VCU and on electrical stimulation all 5 had an absent anal reflex, which may thus prove to be a simple, reliable, non-invasive screening test for sacral neuropathy.

Adult↗
PubMed1984

Clinico-anatomical correlations in uncomplicated stroke.

A method for making clinico-anatomical correlations by computer superimposition of brain maps derived from CT scan images, described in a companion paper, was tested in 19 patients with an uncomplicated left hemiparesis due to acute stroke. Eight patients with an isolated left hemiparesis had small lesions in the most rostral part of the right internal capsule. The composite lesion maps of 11 patients whose left hemiparesis was complicated only by spinothalamic sensory loss showed a larger area of damage more caudally in the posterior part of the posterior limb of the capsule, abutting the thalamus. The close correlation between the results obtained by this method and those obtained in previous clinico-pathological studies of patients with uncomplicated strokes, confirms the validity of this mapping technique.

Basal Ganglia↗
PubMed1984

A microcomputer assisted method for obtaining composite pictures of focal brain damage.

A method used to produce composite drawings of superimposed areas of brain infarction is described. The method uses a microcomputer interfaced to a digitising pad and linear plotter. Areas of brain damage are drawn on standardised maps, digitised, manipulated in computer memory, and summated using computer graphics facilities. The composites show the position of brain damage in groups of patients as a contour map of the extent of lesion overlap. The method can be used to study neurological and neuropsychological deficits using CT-scan, or other imaging techniques. Deep and superficial lesions may be displayed equally well.

Cerebral Infarction↗
PubMed1984

Individual motor unit analysis in the diagnosis of disorders of urethral sphincter innervation.

A technique is described for recording the electromyographic activity of striated muscle in the urethral sphincter. Using a concentric needle electrode and an oscilloscope with a delay line and trigger, individual motor units were isolated and measured. To validate the method as a means of detecting pathology, the results are presented of analysis of the motor units of a group of patients with disturbances of micturition, known to have either cauda equina lesions or pelvic nerve injury. These results are compared with those from a group of controls. In the control group 93% of the motor units were less than 6 ms in duration and 2.0 mv in amplitude. Of motor units recorded from patients with cauda equina or pelvic nerve injury 59% exceeded the control ranges for amplitude or duration. It is concluded that quantitative analysis of individual motor units may be a helpful technique in the investigation of patients with disorders of micturition.

Adult↗
PubMed1984

Dementia due to tumours of the corpus callosum.

The clinical features of 16 cases of tumours of the corpus callosum are described. Many presented with mental changes which were eventually obvious in all but one of the patients. The need to consider these tumours in the differential diagnosis of dementia is discussed.

Adolescent↗
PubMed1984

Infection of the central nervous system by Listeria monocytogenes: a review of 54 adult and juvenile cases.

The clinical features in 54 juvenile and adult patients with Listeria monocytogenes infection of the central nervous system are described. Thirty-one of the patients had pre-existing chronic disease; the remainder were previously healthy. Twenty of the patients, the 'meningo-encephalitic group' developed focal neurological signs. The remaining 34, the 'meningitic group' exhibited no focal signs other than those caused by increased intracranial pressure. The 'meningitic group' differed from the 'meningo-encephalitic group' in that the cerebrospinal fluid white cell count, protein and glucose levels were markedly more abnormal and the prognosis worse. Evidence of septicaemia was found only in the 'meningitic group'. Meningo-encephalitis may represent a modified response to listerial infection typified by granulomatous rather than a suppurative response. The predominance of this response that was demonstrated in females may indicate partial immunity, the result of previous Listeria monocytogenes colonisation of the female genital tract. Listeria monocytogenes infection is treatable and should be considered in patients with meningitic or encephalitic illness. Repeated blood cultures may be required to establish the diagnosis.

Adolescent↗
PubMed1984

Cervical bruits and asymptomatic carotid stenosis.

Since carotid artery atheromata can underlie 50 per cent of strokes, difficulties over the value of surgery have arisen in two groups of patients: those with cervical bruits discovered during routine neurovascular examination; and those being prepared for cardiac or aortoiliac surgery who are known to be at risk of peroperative stroke.

Age Factors↗
PubMed1984

Effects of maternal epidural anesthesia on neonatal behavior.

Lidocaine may be expected to have a greater effect on neonatal neurobehavior than chloroprocaine because of differences in pharmacology. However, recent reports have been contradictory. Therefore, the purpose of this study was to test the hypothesis that the Brazelton Neonatal Behavioral Assessment Scale (BNBAS) score would be lower when lidocaine is used as a local anesthetic than when chloroprocaine is used, and that any effects would be related to cord blood drug levels. Ninety-nine healthy mother/infant pairs were studied. Clinical characteristics, pharmacological data, and BNBAS scores were collected and analyzed using statistical techniques that included stepwise multiple regression and repeated measures analysis of variance. The results showed, that at less than 5 hr of age, the chloroprocaine group performed significantly better on the motor cluster. At 3 days of age, the chloroprocaine group did significantly better on the autonomic cluster. Cord venous concentrations of lidocaine were the only drug variables that correlated with performance on the autonomic items; the higher the concentration, the poorer the BNBAS score. All of the cluster scores showed significant improvement with age except for regulation of state. Furthermore, the route of delivery was significantly related to regulation of state with cesarean babies performing better. Finally, a three-way interaction (test X delivery X drug) was found for the orientation cluster. The data suggest that the difference in performance on the BNBAS associated with lidocaine is very subtle and that other perinatal factors can influence performance on the BNBAS more than the type of local anesthetic used.

Adult↗
PubMed1983

A sex difference in the effect of aspirin on "spontaneous" platelet aggregation in whole blood.

Platelet aggregation can be measured in whole blood by monitoring the fall in single platelet count in an electronic platelet counter. The aggregation that occurs when whole blood is stirred in a small cuvette ("spontaneous aggregation") or upon the addition of collagen has been studied in citrated whole blood from male and female volunteers. Aspirin 40 micrograms ml/l inhibited aggregation induced by collagen in both sexes but spontaneous aggregation was only affected by aspirin in males. These results may help explain the sex difference apparent in the results of some clinical trials of aspirin as an antithrombotic agent.

Aspirin↗
PubMed1983

[The hematocrit and cerebrovascular accidents].

That an elevated haemoglobin or haematocrit is a risk factor in stroke is suggested by the prospective epidemiological evidence from Framingham. Our own study of a series of patients with transient ischaemic attacks revealed that even when due allowance was made for interaction between haematocrit, hypertension and smoking, there was still evidence that both male and female patients had a higher haematocrit than age and sex matched controls. Toghi's autopsy study further shows that cerebral infarction is more frequently found in the elderly population in subjects with a high haematocrit, the effect being most obvious in the presence of severe cerebral atherosclerosis. Cerebral blood flow is inversely related to haematocrit, reflecting the physiological maintenance of oxygen supply according to the metabolic demands of cerebral tissue. When oxygen carriage is enhanced at high haematocrit, flow falls. This could however, predispose in the face of atheroma to thrombosis, a suggestion given some support by the finding that amongst TIA patients the greatest proportion with a haematocrit over 50 were found among those with thrombotic carotid occlusion. The effect of haematocrit on flow might become limiting when considering collateral flow, and flow in a maximally dilated vascular bed in the territory of recent infarction. This hypothesis is supported by the finding that the size of the cerebral infarct accompanying carotid occlusion is greater in patients with an elevated haematocrit.(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebrovascular Circulation↗
PubMed1983

Cerebral blood flow studies with 123iodine-labelled amines.

The cerebral distribution of a new class of 123I radiopharmaceuticals was determined by emission tomography after the isotope had been injected intravenously into 20 patients with a variety of neurological disorders. Regional cerebral blood flow images of diagnostic quality were obtained in all cases. Early and late ischaemic stroke showed up as areas of impaired perfusion, and gliomas and secondary deposits as areas of increased or reduced blood flow. A hyperaemic focus was clearly seen in an epileptic patient in whom other imaging techniques, including CT scanning and electroencephalography, had been uninformative. This new technique promises to be an extremely useful addition to the range of radioisotope brain scanning methods.

Adult↗
PubMed1983

A combined morphological and electrophysiological study of conduction block in peripheral nerve.

The reliability of the electrophysiological criterion of conduction block in determining the presence of focal demyelination in a peripheral nerve has been studied in an animal model. Demyelination was produced in the rat tibial nerve by one or two closely spaced microinjections of lysophosphatidylcholine (LPC). Histological and electrophysiological data were obtained on the acute lesion (up to 6 days), and during recovery (up to 11 weeks). Single LPC injections produced a lesion of very variable severity. Double injections more reliably produced a severe lesion with marked conduction block. Slight axonal damage was occasionally seen in nerves showing severe demyelination. The ratio of amplitude of muscle action potentials evoked by stimuli proximal and distal to the sites of nerve injection was calculated to detect the development of conduction block. The post injection ratio was more than 2 standard deviations below the control mean in 86% of nerves showing signs of demyelination. No control saline injected nerves showed such evidence of conduction block. The severity of the electrophysiological abnormality did not prove a reliable indicator of the severity of the histological lesion, however. The possible reasons for this variability are discussed and it is argued that caution should be exercised when interpreting this particular electrophysiological finding in clinical practice.

Animals↗
PubMed1983

Stereotaxic thalamotomy in 55 cases of dystonia.

The results of stereotaxic thalamotomy in 55 cases of dystonia are presented. The 16 cases with generalized dystonia were of varied pathogenesis, only 7 being typical of the idiopathic form of adolescent onset. Four of the 16 cases benefited considerably, but the others showed little or no lasting improvement. These results are in contrast to those obtained by Cooper (1976). Of the 27 cases with segmental or focal dystonia, 22 had spasmodic torticollis; 16 of these had bilateral thalamotomies, and 62 per cent were much improved. The incidence of operative complications, in particular dysarthria, was high following bilateral lesions. The incidence of hemiparesis, known to have persisted for more than a year, was 15 per cent. This complication was as frequent in those with unilateral as with bilateral thalamotomies. The incidence of dysarthria in those without preoperative bulbar dystonia was much higher in those who had bilateral lesions (56 per cent) as compared with those who had unilateral lesions (11 per cent). The group that has been identified as benefiting greatly from stereotaxic surgery comprises those with hemidystonia following unilateral brain damage. In these patients, symptomatic improvement in abnormal movement is striking and the incidence of operative side effects from unilateral lesions is low.

Dysarthria↗
PubMed1983

Effect of contrast media on red cell filtrability and morphology.

The effects of radiological contrast media on red cell morphology and rigidity have been studied. It has been shown that all the contrast agents studied, even when iso-osmolar with plasma, produce changes in red cell morphology, revealing the intrinsic chemotoxicity of contrast medium molecules. The changes are greatest with the most strongly protein-bound medium investigated--meglumine ioglycamide. The effects on red cell rigidity, on the other hand, appear purely a function of osmolality, being entirely reproducible with hyperosmolar solutions of saline. At concentrations iso-osmolar with plasma no effect on deformability is observed. Since the increased rigidity of red cells induced by contrast medium adversely affects blood flow, the use of the new low-osmolality contrast media is particularly recommended in pulmonary angiography and renal arteriography.

Contrast Media↗