Search PubMed⌕ Search

Biomedical subjects

R E Williams

Publications and source records attributed to R E Williams.

At least 163 records · Page 9Linked to original sources
PubMed1980

Evaluation of CGA 72662 as a topical spray and feed additive for controlling house flies breeding in chicken manure.

The insect growth regulator, CGA 72662 (N-cyclopropyl-1,3,5-triazine-2,4,6-triamine), was tested both as a topical spray and feed additive for controlling the house fly (Musca domestica L.) breeding in chicken manure. Dosage concentrations of .025%, .05%, and .1% were sprayed on sections of manure surface in a shallow pit egg layer operation at rates of 1.9 and 3.8 liters/10.2m2. AT 17 days posttreatment each concentration at both rats, except .025% at 1.9 liters/10.2m2, provided at least a 70% reduction of native house flies and 100% inhibition of laboratory reared house flies. CGA 72662 fed to both hens and broilers at rates of 1.5 ppm and 5 ppm provided up to 100% mortality of house flies 1 day after birds were started on treated feed to 1 day after treated feed was removed.

Animal Feed↗
PubMed1979

Photoaffinity inactivation of the enkephalin receptor.

An arylazide enkephalin derivative, [D-Ala2,Met5]enkephalin-Tyr-N-(2-nitro-4-azidophenyl) ethylenediamine (ETN), has been synthesized. In the dark, it inhibited the binding of [3H]enkephalinamide to enkephalin receptor-rich NG-108 cell membranes with an I50 = 2.2 X 10(-8) M or KI = 7 X 10(-9) M, assuming competitive inhibition. Photolysis of membranes in the presence of ETN caused irreversible inactivation of the enkephalin receptor, but inactivation was prevented by the addition of enkephalin, the half-effective concentration being 3 x 10(-9) M. ETN appears to be an effective photoaffinity label for the enkephalin receptor.

Affinity Labels↗
PubMed1979

The interaction of polymeric viologens with hydrogenases from Desulfovibrio desulfuricans and Clostridium pasteurianum.

The interaction between hydrogenases from either Desulfovibrio desulfuricans or Clostridium pasteurianum and electron donors methyl viologen or polymeric viologens was examined. Extracts from each organism contained a single gel electophoretic band of active hydrogenase. The hydrogenase of D. desulfuricans was much more stable than that of Cl. pasteurianum. With methyl viologen apparent Km and Vm values were 0.5 mM and 0.62 mumole H2/min per milligram protein for the Cl. pasteurianum and 0.7 and 6.2 mumole H2/min per milligram protein, respectively, for the D. desulfuricans enzyme. The hydrogenases bound the polymeric viologens more tightly than methyl viologen, more so for the enzyme of D. desulfuricans than for Cl. pasteurianum. Maximal rate of hydrogen production was less with the polymeric than with methyl viologen. The results suggest that the D. desulfuricans enzyme in conjunction wiion than that from Cl. pasteurianum.

Clostridium↗
PubMed1979

Acute toxicity of micronized 8-methoxypsoralen in rodents.

The acute oral and intraperitoneal LD50 values of micronized 8-Methoxypsoralen were determined in rats and mice. The values obtained in the present study were lower than those previously reported. The suggestion is made that the discrepancy in the LD50 values may possibly be attributed to differences in compound particle size in the preparations used.

Administration, Oral↗
PubMed1978

Studies of erythrocyte membrane loss produced by amphipathic drugs and in vitro storage.

Four amphipathic drugs, primaquine, propranolol, chlorpromazine and tetracaine, were used to cause endocytosis in glucose-depleted red cells, and the relative reduction of membrane surfaces was measured by the toluidine blue (TB) method. The TB measurements correlated well with the observed electron microscopic alterations. In vitro blood storage studies indicated loss of cell membrane during storage correlated with decreasing uptake of TB by the red cells. Regeneration of cellular ATP with adenosine did not always restore TB uptake by the cells. Loss of red blood cell membrane either by exocytosis or endocytosis may occur during normal in vivo or in vitro ageing, and may be increased in pathological states or by the action of drugs.

Adenosine Triphosphate↗
PubMed1978

Urethral tumours.

A series of 33 patients with urethral tumours has been studied to assess the risk of dissemination by endoscopic diathermy. This risk is less than that of cystourethrectomy. Urethral tumours should be treated like the vesical tumours they follow and so closely resemble: by endoscopic treatment while they remain small, sparse and superficial; by cystourethrectomy as soon as they become larger and more extensive. Recurrence of tumour in the urethral stump following cystectomy should always be treated by urethrectomy.

Aged↗
PubMed1978

Potato spindle tuber viroid: circular dichroism spectrum and physical chemical studies of its interaction with ethidium bromide.

The presence and extent of base-paired secondary structure in the protein-free potato spindle tuber viroid RNA has been investigated by spectroscopic techniques. Dye-binding studies with the intercalating dye, ethidium bromide, indicate the presence of base-paired regions in the molecule. Variation of the induced chirality in the dye with the dye to RNA phosphate ratio indicate the presence of two base-paired regions in the molecule.

Chemical Phenomena↗
PubMed1978

Effects of Gulf Coast ticks on blood composition and weights of pastured Hereford steers.

Studies conducted in 1975 and 1976 were made of lightweight Herefored steers, pastured on native grass pasture and infested with Gulf Coast ticks, Amblyomma maculatum Koch. The effects of tick infestations on the blood composition and weights of steers over an 8-week period were measured each year and compared to tick-free animals maintained similarly. By the end of the 8-week study infested animals averaged 8.21 kg less than control animals in 1975 and 12.42 kg less in 1976. Of the blood parameters measured significant decreases in Hb, and a lymphopenia, neutrophilia, and basophilia occurred in infested animals in 1975. In 1975 and 1976 after infestations began significant increases occurred in total serum protein, serum globulin, and plasma fibrinogen, and decreases occurred in the albumin/globulin ration of infested animals. Of the serum globulin fractions, only gamma globulin increased in infested animals in 1975 and alpha globulin in 1976. Also, during both years, decreases occurred over time in the number of ticks attaching.

Animals↗