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Biomedical subjects

W C Wallace

Publications and source records attributed to W C Wallace.

28 records · Page 2Linked to original sources
PubMed1982

The fate of N-nitrosodiethanolamine after oral and topical administration to rats.

14C-labelled N-nitrosodiethanolamine ([14C]NDELA) was given to Osborne-Mendel rats at two dose levels, 0.5 or 50 mg/kg, by oral or topical administration. The excreta and tissues were analysed at various times from 4 hr to 1 wk after administration to determine the distribution of radioactivity. After oral administration, [14C]NDELA was rapidly absorbed from the gastro-intestinal tract, distributed throughout all organs and tissues, and then excreted, mainly via the kidneys. The tissue concentration reached a peak at 8 hr, but some activity remained after 1 wk. After topical application NDELA was slowly absorbed percutaneously, but once absorbed was distributed as in the orally dosed rats. Metabolic profiles of urine and bile samples from both the orally and topically dosed rats were identical, although the quantities varied. In addition to unchanged NDELA, one metabolite was present. The dose level had little effect on the quantities of unchanged NDELA or the metabolite present.

Administration, Oral↗
PubMed1980

Effect of riboflavon analogs on the growth of Tetrahymena pyriformis.

Several analogs of riboflavin differing with respect to the substituent at C7, C8 or C10 were examined for their ability to replace riboflavin and to act as riboflavin antagonists in inhibiting growth of Tetrahymena pyriformis. Generally, the analogs with altered substituents at C7 or C8 (the 8-ethyl, 7,8-diethyl, 7-chloro and 8-chloro analogs) supported some growth but inhibited riboflavin-supported growth. However, the 8-bromo analog had no biological activity. The 7-ethyl analog with a bis(2-hydroxyethyl)aminoethyl side chain was the most potent antagonist. These results were compared with those observed in Lactobacillus casei and the rat.

Animals↗
PubMed1975

The metabolism of saccharin in animals.

Rats given oral doses of [3-14C] saccharin excreted 56-87% of the labeled dose in the urine and 10-40% in the feces during 7 days. Distribution studies showed that the highest levels of 14C were in the kidneys and bladders. The bile was not a significant route of excretion. The presence of labeled CO2 in expired air indicated that saccharin was decarbosylated to a slight degree. DEAE chromatographic separation and isolation of labeled compounds from urine samples showed that more than 99% of the urinary 14C was unchanged saccharin. Up to 1.0% of the 14C was a metabolite identified as 0-sulfamoylbenzoic acid. Comparative metabolic profiles of a dog, rabbit, guinea pig and hamster indicated that there was little difference in the pattern due to animal species or dose level.

Anesthesia↗
PubMedDate not supplied

Cardiac function after eight hour storage by using polyethylene glycol hemoglobin versus crystalloid perfusion.

Efforts to extend myocardial preservation for transplantation by crystalloid perfusion have been limited by edema and compromised function. We hypothesized that hypothermic perfusion preservation with a polyethylene glycol (PEG) conjugated hemoglobin solution may extend preservation times. The purpose of this study was to compare cardiac function after continuous perfusion by using a hypocalcemic, normokalemic crystalloid perfusate with and without the addition of PEG-hemoglobin (Hb). The hearts of 20 anesthetized and ventilated New Zealand White rabbits were harvested after cold cardioplegic arrest. Group I (n = 10) hearts were continuously perfused with a hypocalcemic, normokalemic 3% bovine PEG-Hb solution at 20 degrees C and 30 mm Hg for 8 hours. Group II (n = 10) hearts were continuously perfused with an identical crystalloid solution without PEG-Hb for 8 hours under the same conditions as group I hearts. Cardiac function was measured with a left ventricular force transducer after transfer to a standard crystalloid Langendorff circuit at 37 degrees C and an aortic root pressure of 59 mm Hg. After 8 hours of perfusion preservation, heart rate was similar for groups I and II (p = not significant [NS]). Coronary blood flow after and during preservation was similar between PEG-Hb and crystalloid preserved hearts (p = NS). Left ventricular developed pressure, peak dP/dt, and peak -dP/dt were superior in hearts preserved with PEG-Hb. Percent water of total ventricular weight was 82.0% for group I and 81.6% for group II (p = NS). Continuous perfusion preservation of rabbit hearts for 8 hours with a hypocalcemic normokalemic PEG-Hb based solution at 30 mm Hg and 20 degrees C yields left ventricular function that is superior to perfusion with a similar crystalloid solution without PEG-Hb, despite similar myocardial edema and coronary flow. Extended cardiac perfusion preservation with this PEG-Hb based solution deserves further study, including comparison with traditional cardioplegic preservation solutions.

Animals↗