Time-management strategy for women.
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Administrative Personnel↗
Biomedical subjects
R A Mackenzie
Publications and source records attributed to R A Mackenzie.
The management process in 3D. A diagram showing the activities, functions, and basic elements of the executive's job.
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Administrative Personnel↗
Primary lymphoma of the central nervous system: a case report.
A 46-year-old female presented with a 1-week history of mental change, confusion and headaches. Investigations revealed evidence of sterile meningitis. CAT scanning of the brain demonstrated marked contrast enhancement around the ependyma, and later examinations showed extension of the process deep into the white matter, Cerebral biopsies were non-diagnostic and, despite ventricular drainage and treatment with antibiotics and high dose steriods, the patent died. At postmortem there was extensive tumour tissue distributed in a butterfly shape around the ventricles, and microscopy revealed typical apperances of primary CNS lymphoma. On the basis of the experience of this case and a review of recent literature, it is suggested that the CAT scan appearances of this tumour are quite typical, and that cranial irradiation may be justified in the absence of specific histological diagnosis.
Brain Neoplasms↗
A double-blind trial of bromocriptine in Parkinson's disease.
Twenty-two patients entered a double-blind trial to test the efficacy of bromocriptine therapy in patients with Parkinson's disease who were already stabilized on conventional L-Dopa therapy. Of these, three patients who were receiving placebo withdrew when no improvement occurred and control became complicated. Another four patients taking active drug withdrew because of side effects, but only in one case was the symptom (nausea and vomiting) thought to be a true effect of the drug. Of the 15 patients who completed the trial, nine were taking active drug and six took placebo. Although more than half the patients in each group were subjectively improved, measurement scales of functional disability and physical examination revealed no significant change in either group. Side effects encountered included nausea, dyskinesia, and hallucinations. It was concluded that bromocriptine does not offer any additional benefit to patients with Parkinson's disease who are stabilized on L-Dopa therapy, but may have a place in those patients who encounter side effects due to fluctuations in serum and tissue levels of L-Dopa.
Bromocriptine↗
An evaluation of bromocriptine in the treatment of Parkinson's disease.
22 patients entered a double-blind trial to test the efficacy of bromocriptine therapy in patients with Parkinson's disease already established on conventional levodopa therapy. 3 patients on placebo withdrew when no improvement occurred and control became complicated. 4 patients on active drug withdrew because of various symptoms, but in only 1 case were these (nausea and vomiting) thought to be a real drug effect. Of the 15 patients who completed the trial, 9 were on active drug and 6 were on placebo. Although more than half the patients in each group were subjectively improved, measurement scales of functional disability and physical examination revealed no significant change in either group. Side effects encountered included nausea, dyskinesiae and hallucinations. It is concluded that bromocriptine does not offer any additional benefit in most patients with Parkinson's disease who are well stabilised on levodopa therapy, but may have a place in those patients who encounter side effects due to fluctuations in serum and tissue levels of levodopa.
Aged↗
A micro-electrode study of peripheral neuropathy in man. Part 1. Responses to single graded stimuli.
Multi-unit micro-electrode recording were obtained from sensory fascicles of the sural and median nerves of 12 control subjects and of 28 patients with peripheral neuropathy. Spontaneous activity and mass responses to mechanical and electrical stimuli were examined. Mechanoreceptor function appeared normal but there was a reduced number of responsive receptors in peripheral neuropathy. The electrical activation threshold of nerve fibres of all conduction velocities was increased in neuropathy and a greater number of fibres needed to be activated for preception to occur. Clinical sensory impairment was associated with a reduction in size of the initial compound action potential of the maximal evoked neurogram and with dispersion of fibre responses. Pathological slowing of fibre conduction velocity was demonstrated in demyelinating neuropathy but in most cases of axomal degeneration the changes in velocity could have been due either to a reduced number of fast conducting fibres, or to conduction block. No changes were observed in C-fibre activity in these patients.
Adult↗
A micro-electrode study of peripheral neuropathy in man. Part 2. Responses to conditioning stimuli.
Surface, needle and micro-electrode recordings were obtained from sensory nerves of patients with various types of peripheral neuropathy. Changes in amplitude and conduction velocity of nerve action potentials were measured after a single conditioning stimulus and after tetanic stimulation for 2 min. In patients with hereditary forms of axonal degeneration (AD), recovery processes of nerve fibres of all conduction velocities were normal; in acquired forms of AD fibres with conduction velocity less than 30 m/sec had greater and more prolonged post-tetanic depression than control nerves of similar conduction velocity. Where neuropathy was associated with segmental demyelination (SD), fibres of all conduction velocities had prolonged recovery processes after both single and tetanic stimulation. The changes were especially marked at higher skin temperature, and were greater than the changes seen in nerves with acquired forms of AD. Finally, 2 sural nerves were studied during the process of Wallerian degeneration after a biopsy had been obtained proximally, and recovery processes did not change during the period of degeneration. Perceptual abnormalities were similar in AD and SD. It is suggested that changes in recovery processes of nerve fibres with segmental demyelination or regeneration after injury contribute to the perceptual abnormalities which occur in clinically encountered peripheral neuropathies.
Action Potentials↗
Cutaneous afferent activity in median and radial nerve fascicles: a microelectrode study.
Cutaneous afferent activity was recorded in fascicles of the median and radial nerves of normal subjects using percutaneous microelectrodes. Multi-unit fascicular responses were dominated by activity in large myelinated fibres. Easily tolerated electrical stimuli evoked the full spectrum of fast and slow myelinated fibre activity but more intense levels were required to activate unmyelinated fibres. Correlation of the evoked potentials and the sensations reported by the subject suggested that fast myelinated fibres mediate tactile sensations. Pricking pain appeared with the activation of slow myelinated fibres. The only sensations induced by electrical stimuli were tactile or painful.
Adult↗
Fibre function and perception during cutaneous nerve block.
In awake human subjects, neural responses in radial nerves to electrical stimulation were recorded with intrafascicular tungsten microelectrodes. Changes in the activity of individual fibre groups during blocking procedures were recorded and correlated with simultaneous alterations in the perception of standardized stimuli. Light touch sensibility in hairy skin appeared to depend on the integrity of A-beta-gamma fibres, cold and pinprick on A-delta fibres, and warmth and dull pain on C fibres.
Action Potentials↗
Fibre function and perception during cutaneous nerve block.
In awake human subjects, neural responses in cutaneous nerves to electrical stimulation were recorded with intrafascicular tungsten micro-electrodes. Changes in the activity of individual fibre groups during blocking procedures were recorded and correlated with simultaneous alterations in the perception of standardized stimuli. Light touch sensibility in hairy skin was mediated by A-beta-gamma fibres, cold and pinprick by A-delta fibres and warmth and dull pain by C fibres.
Action Potentials↗