Comment on the recent results of Hopewell, Morris and Dixon-Brown on radiation myelitis produced by irradiation of very short segments of rat spinal cord.
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Animals↗
Biomedical subjects
B Berner
Publications and source records attributed to B Berner.
[Effects of petroleum derivatives and psychological stress on eye changes in prospective studies].
Prospective study of workers exposed to simultaneous action of petroleum derivatives and psychic stress proved statistically remarkable differences between the first study and control study (after two years) as related to macular degeneration and opacification of the lens. So far, the results do not seem to point to these phenomena as related to the differences of age and training period between the two groups. For the ultimate assessment of the effect of simultaneous intoxication with petroleum derivatives and psychic stress, it is necessary to confront the results of the study with those obtained after examining the control group including persons of the same age.
Adult↗
Dopamine release and metabolism after chronic delivery of selective or nonselective dopamine autoreceptor agonists.
The metabolism and release of dopamine by rat mesostriatal and mesolimbic dopamine neurons were determined after 2 or 14 days of subcutaneous administration via Alzet minipumps of a selective (CGS 15855A) or nonselective (apomorphine) dopamine autoreceptor agonist. Bioassays and high performance liquid chromatography assays showed that each drug was accurately delivered for the 2- and 14-day periods. CGS 15855A levels in the plasma and brain increased with increases in the daily dose given, although plasma levels of CGS 15855A at 14 days were less than those at 2 days for each dose. Striatal dopamine metabolism and release, assessed with dihydroxyphenylacetic acid and 3-methoxytyramine concentrations, respectively, were suppressed by 2-day treatments of 50-200 micrograms/day CGS 15855A or 250 micrograms/day apomorphine. These suppressions were potentiated by acute challenge with 1 mg/kg intraperitoneally of CGS 15855A or 2 mg/kg subcutaneously of apomorphine. In contrast, dopamine metabolism and release were unchanged after 14 days of administration of 40-400 micrograms/day of CGS 15855A or 250 micrograms/day of apomorphine, even when plasma levels of drug were as high as at 2 days. Dopamine release was decreased in only one of six groups 30 min after an additional acute injection of the agonist given for 14 days, whereas dopamine metabolism was decreased in five of six groups. Striatal dopamine levels were increased 20-57% after 14 but not 2 days of cgs 15855A followed by acute challenge with the vehicle or CGS 15855A injections. Thus, the responsiveness of dopamine neurons to the release-suppressing properties of dopamine autoreceptor agonists is mostly attenuated between 2 and 14 days of treatment. The ability of chronic CGS 15855A treatments to increase dopamine levels and, with acute CGS 15855A, to decrease DOPAC levels, indicates that autoreceptor control of dopamine metabolism is partly retained after chronic autoreceptor agonism.
Animals↗
Pharmacokinetics of transdermal drug delivery.
The pharmacokinetics of drug delivery from transdermal controlled-release devices consisting of (a) a membrane plus a reservoir or (b) a monolithic slab are examined. For the period when the devices act as if the drug reservoir were infinite, simple relationships for the steady-state slope and time lag are derived and studied. An analysis of the time region when depletion of the finite dose is obtained is used to estimate the useful device lifetime. Applications to patch design are discussed.
Administration, Topical↗
Finite dose pharmacokinetics of skin penetration.
A model for estimating in vivo skin permeability coefficients for finite doses is presented. The ratio of the maximum value of the excretion rate to the steady-state flux is a function of the thickness of the applied vehicle and the vehicle-skin partition coefficient. The decay rate of the excretion is a function of skin-vehicle parameters for large doses and, under certain conditions, can even reduce to the total excretory rate constant as the dose is decreased.
Chemistry, Pharmaceutical↗
Application of diffusion theory to the relationship between partition coefficient and biological response.
A diffusion model for transport through multilaminates is studied as a possible way to predict the optimal biological response of a set of congeners with respect to the oil-water partition coefficient, P. The model predicts the bilinear form typical of biological response data and, unlike the earlier kinetic model, also relates the results to physical processes, predicts the structure with the optimal response in terms of diffusion constants, and shows such an optimum prior to steady state for an infinite dose. Diffusion through an oil-water multilaminate causes extraordinary separation of permeating species based on partition coefficient and diffusion constant for times shorter than the lag time.
Diffusion↗
[Evaluation of the organ of sight in workers at the Masovian Refinery-Petrochemistry Plant. II. Correlation of the results of ophthalmological tests with the results of specialized and laboratory tests].
Basing on the results of examinations of 752 workers of the Refinery-Petro-chemistry Plant, correlations have been searched for between changes in the macula region of retina and disturbances found due to other specialist tests (internal, laryngological, dermatological), as well as laboratory--and toxicological investigations. A statistically significant correlation was found between changes in the macula and dysgeusia at the water-sewage division as well as the level of triglycerides at the phenol-and-total cholesterol division. A strict correlation was found between an increase in arterial hypertension and the rate of macula changes.
Ageusia↗
[The state of the organ of vision in workers in the petrochemical industry. I. Results of ophthalmological examinations].
The ophthalmological examinations of petrochemical plant workers that have been carried out so far did not enable working out a simple method of rapid ophthalmological evaluation of subclinical aromatic hydrocarbons poisonings. Neither the results of our own studies nor the experience of other authors explained fully the pathogenesis of the described spot lesions. Further observations are advisable to account for that issue.
Chemical Industry↗
Kinetic analysis of relationship between partition coefficient and biological response.
Both nonequilibrium and equilibrium models were proposed to explain the optimal biological response to a set of congeners with respect to the oil-water partition coefficient (P). A detailed analysis of the kinetic model proposed by Hansch demonstrates the bilinear form of the model, with the initial slope of the logarithm of the concentration for 50% receptor binding versus log P having a slope of greater than one. This result is in contrast to the equilibrium model for an initial slope of less than one. Thus, a criterion is established for deciding whether equilibrium or nonequilibrium processes apply.
Biological Transport↗
Partition coefficients of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO0 in erythrocyte lipids in multiple sclerosis.
Electron spin resonance (ESR) was used in a search for a possible generalized membrane defect underlying myelin instability in multiple sclerosis (MS). In contrast to most ESR studies of biological membranes, a small, nonelectrolyte spin label, TEMPO, was chosen; its partition coefficient was determined in extracted erythrocyte lipids from MS patients and normal controls. No differences were observed the advantages and limitations of TEMPO in comparison with lipid spin labels as probes for the study of biological membranes are discussed.
Cyclic N-Oxides↗
Psychosocial factors in the rehabilitative adjustment of quadriplegia. A case report.
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Adaptation, Psychological↗
Secretin and gastric lipase secretion.
BACKGROUND: Gastric lipase secretion is stimulated by gastrin in plasma, but its regulation by secretin is unknown. METHODS: In 7 normal persons we investigated the effect of exogenous secretin on the output of gastric lipase stimulated by intravenous gastrin-17. The gastric content was measured using a nasogastric tube for aspiration. The quantitative lipase secretion was measured by an enzyme-linked immunosorbant assay (ELISA) and the lipolytic activity by a kinetic assay. Plasma concentrations of secretin and gastrin were measured by radioimmunoassay. RESULTS: Gastric lipase secretion (the quantity as well as the lipolytic activity) was significantly stimulated by gastrin. In response to secretin infusion, the lipolytic activity increased as acid secretion decreased. CONCLUSION: Secretin in postprandial concentrations does not influence the quantitative gastric lipase secretion stimulated by gastrin, but it increases lipolytic activity due to inhibition of acid secretion.
Adult↗
[Disorders of color vision in employees of the Masovian Refining and Petrochemical Industries in Płock].
Attention is drawn to the problem of the influence of the petrol derivates on the frequency of acquired dyschromatopsia. It has been observed--on the basis of performed examinations of the color vision by means of the Farnsworth-Munsell's 100-Hue test--that the general numerical index of the faults is increasing proportionally to the period of employment, i.s. the period of the contact of the workers with the derivates of petrol.
Adult↗