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Biomedical subjects

R Shields

Publications and source records attributed to R Shields.

At least 37 records · Page 2Linked to original sources
PubMed1977

Ammonia absorption from the canine colon after portacaval shunt.

Ammonia absorption was studied from Thirty-Vella colon loops in 6 dogs. Four underwent an end-to-side portacaval shunt and it was shown that absorption of ammonia from the colon significantly increased postoperatively. Absorption of ammonia from various solutions was also measured before and after portacaval shunt and it was shown taht absorption was increased from a high pH solution and from a solution with a high bicarbonate content and reduced from a low pH, low osmolality and high osmolality solution. Increased deposits of stainable iron were demonstrated in the livers of dogs following portacaval shunt.

Ammonia↗
PubMed1977

Cells regulate their proliferation through alterations in transition probability.

The proliferation of 3T3, 3T6 and SV3T3 cells was examined by time lapse cinephotography under a number of different growth conditions. It was found that the frequency distributions of intermitotic times of cells with widely different proliferation rates are qualitatively and quantitatively explained by the transition probability model of the cell cycle (Smith and Martin, '73). The behaviour of quiescent cells was characterized by very low values of the transition probability. No "out of cycle" or GO compartment of cells was detectable. From a consideration of these results and those in the literature it appears that the rate of cell proliferation is determined by the value of the "transition probability" (P), and that it is the biochemical manifestation of this parameter that regulates cell growth in vitro and in vivo.

Animals↗
PubMed1976

Influence of staphylococcal enterotoxin on water and electrolyte transport in the small intestine.

The direct and indirect effects of staphylococcal enterotoxins A and C on the flux of water, sodium, and potassium have been studied in paired Thiry Vella fistulae in dogs. Administration of toxin resulted in a significant decrease in absorption, both in the loop to which the toxin had been administered and its pair. This decrease in absorption was associated with a decrease in movement out of the lumen, movement into the lumen remaining relatively unchanged. The mechanism of action of staphylococcal enterotoxins is discussed, and comparisons made with other enterotoxins.

Animals↗
PubMed1976

Effect of galactose and sugar substitutes on blood insulin levels in normal and obese individuals.

Eighteen male patients between the ages of 25 and 50 were given on a double blind randomized basis (A) 40 gms. galactose (B) 50 gms. arabinogalactan and 0.11 gm. sodium saccharin (C) 2 gm. methyl cellulose and 0.083 gm. sodium saccharin and (D) 4 gm. galactose, all in 200 ml water. Blood glucose, galactose and insulin levels were determined during a six hour period before and after ingestion. The three first mentioned solutions tasted equally sweet, the fourth was essentially tasteless. None of these feedings altered plasma insulin or glucose levels. It appears that in contrast to other conclusions reached by earlier investigators sweet taste is unable to induce insulin secretion through neurogenic pathways.

Adult↗