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Biomedical subjects

E S Johnson

Publications and source records attributed to E S Johnson.

At least 163 records · Page 9Linked to original sources
PubMed1969

The responses of cortical neurones to monoamines under differing anaesthetic conditions.

1. Noradrenaline, isoprenaline, 5-hydroxytryptamine and acetylcholine have been applied into the environment of single neurones in the cat cerebral cortex by micro-iontophoresis. The influence of anaesthesia on the neuronal responses to these drugs was studied.2. In general, excitation of neurones by noradrenaline occurred commonly in both unanaesthetized encéphale isolé (48%) and N(2)O-halothane anaesthetized preparations (57%) while depressions were less frequent (24 and 20% respectively). The picture differed markedly in barbiturate anaesthetized animals where excitation was uncommon (12%) and the majority of cells (59%) was depressed by noradrenaline. Although fewer cells were studied, similar differences were obtained with isoprenaline and 5-hydroxytryptamine for the three types of preparation. In sharp contrast, the vast majority of cells was excited by acetylcholine in each of the preparations: encéphale isolé 84%; N(2)O-halothane 92%; barbiturate anaesthetized preparations 85%.3. The differing neuronal responses observed in these experimental situations were not the result of variations in the depth of anaesthesia.4. Although the depths at which neurones were encountered within the cortex did not differ in N(2)O-halothane and encéphale isolé preparations, significantly more cells were found in deeper layers of cortex in barbiturate preparations. The proportion of cells excited or depressed by noradrenaline was generally similar at each depth in the three preparations used.5. The distribution of rates of cell firing was strikingly similar in each preparation, and most of the cells studied had frequencies below 10/sec.6. The direction in which a cell responds to noradrenaline is mainly determined by the type of anaesthetic used, and not by the depth of anaesthesia, the rate of cell firing, or cell depth within the cortex. This suggests important differences in the central pharmacology of halothane and barbiturates.

Acetylcholine↗
PubMedDate not supplied

An economic evaluation of oral compared with intravenous ganciclovir for maintenance treatment of newly diagnosed cytomegalovirus retinitis in AIDS patients.

This prospective, clinical economic study was done to determine the cost impact of oral compared with intravenous (i.v.) ganciclovir for the maintenance treatment of newly diagnosed cytomegalovirus (CMV) retinitis in patients with acquired immunodeficiency syndrome (AIDS). Efficacy and safety data were extracted from a trial of oral and i.v. ganciclovir. Medical care utilization and reimbursement data were obtained from the clinical trial, a survey of home care and nursing companies, an 11-member physician panel, and a Medicaid cost database. The primary outcome measures were time to first retinitis progression and associated direct medical care expenditures. Nonmedical costs and quality-of-life benefits were not considered. Based on masked evaluation of retinal photographs, the Kaplan-Meier mean time to first progression was 62 days for i.v. ganciclovir and 57 days for oral ganciclovir (a nonsignificant difference). he expected mean cost of treatment for i.v. ganciclovir was significantly different at $8587.00 compared with $4938.00 for oral treatment. Sensitivity analysis using funduscopically determined mean time to first progression showed similar cost savings. We concluded that oral ganciclovir is a cost-saving alternative to i.v. ganciclovir for the maintenance treatment of AIDS patients with newly diagnosed CMV retinitis. Cost differences are attributable to reduced home care expenditures and lower incidence and costs of treating major adverse events in the oral treatment group.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Lipohyalinosis and miliary microaneurysms causing cerebral hemorrhage in a patient with moyamoya. A clinicopathological study.

Moyamoya is an intriguing and controversial syndrome. This patient study serves to align the pathophysiology of intracranial hemorrhage in moyamoya with the cerebral vascular disease seen with hypertension, or aging. The historical evidence linking lipohyalinosis and microaneurysms to cerebral hemorrhage is reviewed, the pathogenesis of this angiopathy is discussed, and explanations considered for its association with the vascular pattern of moyamoya. We propose that hemodynamics, genetics or both are among the primary operant etiologic factors.

Adult↗
PubMedDate not supplied

Environmental equity and pesticide exposure.

Although people of color and low-income groups bear a disproportionate share of the health risks from exposure to pesticides, research attention has been meager, and data on acute and chronic health effects related to their toxic exposures are generally lacking. Increased resources are needed both to study this issue and to mitigate problems already identified. People of color should be a major research focus, with priority on long-term effects, particularly cancer, neurodevelopmental and neurobehavioral effects, long-term neurological dysfunction, and reproductive outcome. Suitable populations at high risk that have not been studied include noncertified pesticide applicators and seasonal and migrant farm workers, including children.

Body Burden↗