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Biomedical subjects

D R McLean

Publications and source records attributed to D R McLean.

33 records · Page 2Linked to original sources
PubMed1987

Neurologic, audiologic, and electrophysiologic sequelae of bilateral temporal lobe lesions.

A 67-year-old woman with demonstrated intact peripheral and brain-stem auditory pathways presented with sudden deafness secondary to sequential bilateral temporal lobe infarcts. Initial examination revealed no behavioral response to sounds and a mild Wernicke's aphasia. Hearing gradually returned but auditory agnosia persists. Changes seen on the computed tomographic scan and the middle latency auditory evoked response over a seven-month period were analyzed and suggest that the peak component of the middle latency response arises from Heschl's gyrus.

Aged↗
PubMed1987

Effects of temporal lobectomy for treatment of epilepsy on hemispheric functions ipsilateral to surgery: preliminary findings.

Several studies have reported a pattern of ipsilateral deficit and contralateral improvement following temporal lobectomy. Presumably the contralateral improvement is due to cessation of commissural spread, and the ipsilateral deficit to surgical damage to that side. If, as hypothesized, the underlying mechanism is cessation of commissural spread of seizure activity, some ipsilateral improvements might also occur. This question was addressed in a small sample of left (N = 4) and right (N = 5) temporal lobectomy patients. It was found that the left-operated patients demonstrated improvements on tests reported to measure left frontal lobe function. In addition, both left- and right-operated patients improved on a dexterity test with the hand ipsilateral to the side of surgery. The ipsilateral improvement would be due to removal of an active electrically discharging focus impairing ipsilateral function and contralateral function by commissural spread. These data were interpreted to suggest that cessation of commissural spread of seizure activity can result in improvement in regions of the hemisphere ipsilateral to surgery, and that the contralateral hemispheric improvements may include psychomotor functions in addition to memory and IQ changes. Seizure control achieved by surgery may have influenced the pattern of results.

Epilepsy↗
PubMed1986

Cerebral evoked potentials in multiple sclerosis.

Multimodal evoked potentials were analyzed from 58 possible, 62 probable and 100 definite (total 220) multiple sclerosis (MS) patients. Visual evoked potentials (VEP) were most frequently abnormal yielding 39%, 69%, 84% in the three diagnostic groups respectively. Median nerve sensory evoked potentials (SEP) yielded abnormalities in 26%, 65%, 79% respectively. Brainstem auditory evoked responses (BAER) were abnormal in 17%, 39%, 66% respectively. We measured the combined amplitude (CA) of waves III, IV, V in the BAER of these patients as an objective measure of amplitude asymmetry. The CA was considered abnormal if it was 1SD below the lowest CA value in the control group. The CA was abnormal in 9.2% of BAER with normal central conduction time. The BAER diagnostic yield in MS patients increased 11% by using CA analysis.

Adult↗
PubMed1985

Neuropsychological and electrophysiological examination of a patient with Wilson's disease.

A patient with Wilson's disease underwent neuropsychological and electrophysiological examination 4 months following symptom onset. Although motor deficits were more severe, there was considerable impairment of cognitive and intellectual function. Auditory evoked responses were also abnormal in this patient. This case is unusual because of the early severe cognitive deficits.

Adult↗
PubMed1980

Methanol poisoning: a clinical and pathological study.

We report 2 survivors of severe methanol poisoning who developed, apart from blindness, a Parkinson-like extrapyramidal syndrome characterized by reduced initiative, poor voice volume, masked facies, mild tremor, rigidity, and bradykinesia. Both patients were mildly demented and 1 had hyperreflexia and bilateral Babinski responses. Computed tomographic scans in both patients demonstrated bilateral symmetrical infarction of the frontocentral white matter and putamen. Electromyography in 1 patient showed extensive denervation, mainly involving the legs, but normal motor conduction velocities. L-Dopa administered to the more severely affected patient had no effect on the parkinsonian features. Autopsy revealed cystic resorption of the putamen and the frontocentral subcortical white matter in additon to widespread neuronal damage throughout the cerebrum, cerebellum, brainstem, and spinal cord.

Adult↗
PubMed1980

Biochemical markers for Huntington's chorea.

The uptake of dopamine (DA) by platelet rich plasma was assayed in 11 patients with Huntington's chorea (H.C.). The results confirmed the previous observation that platelets from H.C. patients take up, at equilibrium, more dopamine than do platelets from normal control subjects. The mean difference was 50% higher at DA substrate concentrations of 0.11 mM. However, attempts to confirm the higher Na+ - K+ ATPase activity of erythrocyte ghosts from Huntington's chorea patients were unsuccessful.

Adult↗
PubMed1979

Diphenylhydantoin and pulmonary function.

Thirty-nine epileptic patients underwent pulmonary function testing. Twenty-one of these patients, ranging in age from 16 to 44 years, had taken diphenylhydantoin (DPH) for 2 to 17 years. Eighteen patients, who had taken other anticonvulsants for similar time periods served as controls. Five patients in the DPH group had lung volume abnormalities, four had abnormal airway function, and five had abnormalities of alveolar gas mixing. One patient in the control group had lung volume abnormalities, two had abnormal airway function, and five had abnormalities of alveolar gas mixing. Statistical analysis revealed no significant differences between the groups, or between either group and predicted values.

Adolescent↗
PubMed1978

Multiple sclerosis treated with antithymocyte globulin--a five year follow-up.

Multiple sclerosis patients treated with antithymocyte globulin (ATG) were re-evaluated after five years. No long term benefit was found. Notably, the group of patients with an elevated gamma globulin to total protein ration in their C.S.F. and who did particularly well after treatment with ATG also failed to show any long term benefit. Few long term detrimental effects of ATG immunosuppression were identified. The implications of the results are discussed as they relate to the use of immunosuppression in multiple sclerosis.

Adrenocorticotropic Hormone↗
PubMed1977

A statistical procedure for predicting medical school graduates' specialty choices.

A statistical procedure was devised for selecting, from a group of contenders, a relatively small set of variables which most efficiently predict medical specialty choice. While it is possible to predict medical specialty choice with fair accuracy using subsets of variables, predictions are not conclusive enough to be useful in actual decision-making concerning individuals.

Career Choice↗