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Biomedical subjects

W A Skinner

Publications and source records attributed to W A Skinner.

At least 19 recordsLinked to original sources
PubMed1988

Photodynamic toxicity of porphyrins and chlorins for a human tumor cell line: combined light and concentration dose responses for the retained fraction.

In recent years porphyrins and related materials have been tested as antitumor agents. A technique was devised to obtain dose-response curves for the sensitizer fraction that resists one day of elution by tissue culture medium--the retained fraction. We found a steep "threshold" dose response relationship that helps to explain tumor destruction without damage to normal tissues. The family of dose-response curves produced by a wide range of light exposures suggests that chlorins and porphyrins do not act by identical mechanisms. Moreover, they suggest that chlorins will prove superior in practical use.

Carcinoma↗
PubMed1983

Tick repellents II: N-substituted azacyclopentanones and azacyclopentenones.

Several N-substituted azacyclopentanones and azacyclopentenones were synthesized and evaluated as repellents for the brown dog tick Rhipicephalus sanguineus. Several of these compounds were more effective in our test system than were the standard repellents, N,N-diethyl-m-toluamide and butopyranoxyl.

Animals↗
PubMed1980

Topical mosquito repellents XIII: Cyclic analogs of lactic acid.

Numerous cyclic analogs of lactic acid were synthesized to ascertain whether they might act as agonists of antagonists of lactic acid, a known attractant for mosquitoes. These compounds were evaluated with an in vitro blood-feeding test system and an in vivo cloth test. Two of the compounds in the blood-feeding test system showed biphasic results, acting as attractants at low concentrations and as repellents at higher concentrations. Several compounds (III, V, VII, and X) repelled Aedes aegypti mosquitoes in the blood-feeding test system. However, in the in vivo cloth test system, only III repelled the mosquitoes significantly.

Aedes↗
PubMed1979

Structure--activity studies on tetrahydro- and hexahydrocannabinol derivatives.

A series of tetrahydro- and hexahydrocannabinol derivatives was prepared in which the substituents at position 9 were varied. These compounds were evaluated in mice for their effects on locomotor acitivty, body temperature, muscle tone, and analgesia. Depression of body temperature and locomotor function was demonstrated by several compounds, but all were devoid of any significant analgesic activity.

Analgesics↗
PubMed1979

Toxicity of 1,4-dihexylpiperazine.

Attempts to synthesize the insect repellent, N,N'-dihexyl-N-carbomethoxyethylenediamine, led to an impurity which exhibited strong toxicity in the rabbit eye irritation test. Isolation of the impurity led to its identification at 1,4-dihexylpiperazine.

Animals↗
PubMed1977

Influence of human skin surface lipids on protection time of topical mosquito repellent.

Skin surface lipids were extracted from volunteers who had been ranked according to the duration of protection from mosquitoes by diethyltoluamide. These lipids were analyzed by GLC-mass spectrometry for their fatty acid contents. Correlations were found between total skin lipid content and protection time of diethyltoluamide and between certain fatty acid concentrations in the skin lipids and the protection time of diethyltoluamide.

Administration, Topical↗
PubMed1975

Topical mosquito repellents VII: alkyl triethylene glycol monoethers.

Normal and branched-chain aliphatic monoethers of triethylene glycol are effective topical mosquito repellents. In terms of duration of protection, they are generally superior to the corresponding diethylene glycol analogs and some are superior to diethyltoluamide. The n-heptyl monoether of triethylene glycol affords double the protection time of diethyltoluamide under controlled laboratory conditions and appears to be a useful new mosquito repellent.

Administration, Topical↗
PubMed1975

Mutagenic studies of aziridine derivatives derived from various diamines.

Various aziridine derivatives derived from diamines were studied in several biological systems to evaluate their effects on reproduction and as potential mutagens. Considerable variations in the biological activities of these compounds were seen among animal species and among the varied chemical structures. In general, mutagenic responses paralleled the antifertility effects in mice and houseflies and the anticancer effects in mice. The lack of an antifertility effect by N,N'-bis(aziridinylacetyl)-1,8-octamethylenediamine in the rat was quite unexpected in view of its chemosterilant activity in houseflies and mice.

Animals↗
PubMed1975

Quantitative histochemical study of a vitamin E analog on rat gastric cyclic AMP.

The vitamin E analog, 2,2,7,8-tetramethyl-5,6-orthoquinonechroman, unlike vitamin E itself, had been reported to be a potent inhibitor of beef liver cyclic AMP-PDE in vitro (about 3.5 times more inhibitory than theophylline under the same conditions). In this in vivo study, single intraperitoneal injections were given to fasted rats, 15 min before killing, of a solution of 20, and of a suspension of 130, mg analog/kg in 4% ethanol. No significant increases over the 4% ethanol control values in cyclic AMP levels were produced in any of the histological regions of the glandular stomach. However, injection of the 4% ethanol itself produced a rise of about 50% (peak value 4.1 pmoles/mg wet wt, 0.16 pmoles/mug protein-nitrogen) in the cyclic AMP concentrations in the parietal cell region and had no significant effect in any of the other histological zones where the concentrations were much lower.

Animals↗
PubMed1975

Percutaneous penetration following use of hair dyes.

We assess the percutaneous penetration potential of two commercially distributed semipermanent hair dyes. Utilizing several solvent systems in conjunction with thin-layer chromatography (TLC), we found that the commercial formulations contained at least nine component chemicals. Eight adult volunteers had their hair dyed with these preparations and 24-hour urine specimens were collected daily for five days. The urine was lyophilized and extracted with diethyl ether under acid and alkaline conditions. The TLC of urine from four of the eight subjects, taken from one to four days after dyeing the hair, disclosed a purple spot. This spot, though not identified, was the same with both dye preparations. It is likely that these hair dyes not uncommonly penetrate the skin.

Adult↗