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Biomedical subjects

M H Morgan

Publications and source records attributed to M H Morgan.

18 recordsLinked to original sources
PubMed1991

Development of visual evoked potentials following intrauterine growth retardation.

Visual evoked potentials to flash (FVEP) were recorded in 23 symmetrically growth retarded newborns of between 32 and 39 weeks gestational age and 41 normally grown controls. At 9 months post term FVEP recordings were repeated in 14 of the growth retarded and 26 of the control infants. The development of two long latency negative components of the wave form of the neonatal FVEP was delayed in the growth retarded infants. The amplitude of a long latency negative peak in the 9 month post term FVEP was reduced in the growth retarded infants. We suggest that intrauterine growth retardation may affect the development of secondary activity in the visual cortex.

Cerebral Cortex↗
PubMed1989

Abnormal development of visual function following intrauterine growth retardation.

Vernier acuity was measured at 40 weeks post term in 18 infants born with symmetric intrauterine growth retardation (IUGR) and 32 normal (N) infants. Grating acuity was also measured in 12 IUGR and 26 N infants. The mean vernier detection threshold (V.min) was 0.4 octaves higher in the IUGR than in the N infants (P less than 0.04). The mean grating detection threshold (S.min) was 0.2 octaves lower in the IUGR infants (NS). The mean ratio of S.min to V.min was significantly lower in the IUGR infants (1.5 IUGR, 2.7 N, P less than 0.05). V.min was significantly negatively correlated with the head circumference of the IUGR infants at 40 weeks post term. Vernier acuity depends on visual processing at a cortical level. The normal grating acuity in the IUGR infants implies that cortical, rather than optical or retinal factors, underlie the reduced vernier acuity (high V.min). We suggest that the cortical representation of visual space is affected by IUGR.

Female↗
PubMed1989

Cricothyroid muscle paralysis: its recognition and diagnosis.

Cricothyroid muscle paralysis is often missed as the symptoms are not dramatic and the laryngeal observations, on conventional indirect mirror examination, are inconclusive. The anatomy and physiology of the superior laryngeal nerve (SLN) and cricothyroid muscle are described. Three case reports are presented to illustrate our diagnostic techniques. Videofibrolaryngoscopy and electromyography are found to be invaluable tools for the diagnosis of this condition. The importance in diagnosing this entity is discussed.

Adult↗
PubMed1989

Nerve conduction studies.

Nerve conduction studies provide unique quantitative information about neurological function in patients with a variety of neuromuscular disorders. This article emphasizes the need for careful selection of the appropriate procedures, informed interpretation of the data, and correlation of the results with the clinical information about each individual patient's problem, in order to obtain the maximum possible value from the investigation.

Action Potentials↗
PubMed1988

Aldose reductase inhibition in diabetic neuropathy: clinical and neurophysiological studies of one year's treatment with sorbinil.

In a double-blind placebo-controlled trial the effect of Sorbinil (250 mg daily) on diabetic neuropathy was examined. After a 2-month run-in placebo period (with three major assessments) 21 patients were randomized to Sorbinil and 10 to placebo, and all were studied for a further 12 months with neurophysiological measurements at 3-month intervals of nerve conduction velocity in multiple nerves, autonomic function tests, vibration thresholds as well as clinical examination and an extensive self-assessment of symptoms. Two subjects on Sorbinil treatment developed a hypersensitivity reaction and were withdrawn. Metabolic control and severity of neuropathy was not significantly different between groups. There were no changes in symptoms as judged by self-assessment scores. No patient entered the trial with neuropathic ulcers but ulceration developed in 4 patients during Sorbinil treatment and in 1 of the placebo group. No beneficial effect of Sorbinil was demonstrated on either the clinical manifestation or on the neurophysiological measurements made in these neuropathic diabetic patients over 12 months of treatment.

Aldehyde Reductase↗
PubMed1987

Developmental wave form analysis of the neonatal flash evoked potential.

A multiple regression technique was used to describe the wave form of the flash evoked potential (VEP) in 64 neonates born between 28 and 39 weeks of gestation. The successive appearance of new features in the VEP with increasing gestational age at birth was used to define 5 components, of which specimens were obtained by averaging VEPs of 18 selected infants. The VEPs of the other 46 infants were expressed as linear sums of the components, each multiplied by a weighting coefficient. The method accounted for 74 +/- 11% (mean +/- 1 S.D.) of the rms power of the observed VEPs and was used to demonstrate significant effects on wave form maturation from fetal growth retardation and maternal smoking in pregnancy.

Electrophysiology↗
PubMed1976

Intravenous administration of diazepam in patients with chronic liver disease.

The EEG response and drug kinetics after intravenous infusion of diazepam at 1-0 mg/min until nystagmus, dysarthria, and moderate sedation developed, has been investigated in five normal subjects and 17 patients with chronic liver disease. Diazepam induced adequate premedication with a similar clinical response in all subjects with no adverse reactions. Maximal response was during or within five minutes of infusion. The dose of diazepam required in liver chronic disease was 17-9 +/- 1-4 mg (M +/- SEM) compared with 27 +/- 5-4 mg in controls (p less than 0-01). Dose correlated significantly with serum albumin (p less than 0-05). Baseline mean dominant frequency (MDF) and slow wave index (SWI) significantly correlated with albumin (p less than 0-01). After diazepam, the MDF decreased and SWI increased. The change was greatest at the time of maximal clinical response. It was greater in liverdisease and was greatest in patients with previous hepaticencephalopathy. In spite of reduced dose requirements in liver disease, there was no significant difference in plasma concentration at the end of drug infusion...

Chronic Disease↗
PubMed1975

Intention tremor--a method of measurement.

A method of measuring and analysing intention tremor using a linear accelerometer is described. Reasons are given for measuring this particular parameter of the tremor, for using this specific energy conversion device, and for employing the particular form of analysis. A comparison of the numerical values obtained for the amount of tremor activity, compared with a corresponding clinical grading, is made for 30 patients with intention tremor due to a variety of pathological causes. It is shown that the method gives clear correlation with the clinical assessments, although certain discrepancies are noted, and their importance discussed.

Acceleration↗
PubMed1975

Application of an objective method of assessing intention tremor - a further study on the use of weights to reduce intention tremor.

Thirty-one patients with intention tremor due to a variety of causes were subjected to measurements of their intention tremor. The effect of varying amounts of lead weights on the amount of limb tremor recorded was noted. It is concluded that simple methods of treatment may be of benefit, and that an objective method of measuring intention tremor overcomes many of the difficulties of a clinical trial of this type. The method described yields quantifiable data which can be subjected to statistical analysis to help overcome the problem of variability. Bias in the results due to practice or fatigue effects has proved negligible. An optimum amount of lead, which was usually between 600 and 840 g, has been noted.

Adolescent↗
PubMed1974

Medium chain triglycerides and hepatic encephalopathy.

The oral administration of short (C(6)) and medium (C(8) and (C(10)) chain triglycerides produced no clinical or electroencephalographic changes in patients with cirrhosis of the liver. Arterial ammonia levels were also monitored in these patients and showed no significant change after medium chain triglycerides. It was concluded that medium chain triglycerides, known to be of potential value in the treatment of malabsorption in patients with cirrhosis, are not clinically contraindicated, even in patients with evidence of hepatic encephalopathy.

Ammonia↗
PubMed1973

Effect of the beta adrenergic blocking agent propranolol on essential tremor.

A double blind trial of a single 40 mg dose of the beta adrenergic blocking agent propranolol in the treatment of essential tremor produced significant reduction of tremor in four of five patients, but this effect was transient and had considerably diminished within four hours. A month's double blind clinical trial of propranolol, in a dose of 30 mg three times a day, showed that the active drug gave statistically better results than placebo for the attenuation of tremor. The mode of action of propranolol in the reduction of essential tremor is probably a dual one, due both to blockage of peripheral beta receptors and to a central depressant effect.

Adult↗
PubMed1972

Antidepressants and liver disease.

Patients with cirrhosis were found to be extremely sensitive to tranylcypromine, and the use of this drug for the treatment of depression in such patients is contraindicated. Amitriptyline has a wider margin of safety in such patients, but caution is necessary when the higher therapeutic doses are prescribed.

Amitriptyline↗