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Biomedical subjects

M G Waters

Publications and source records attributed to M G Waters.

42 records · Page 3Linked to original sources
PubMed1984

D- and L-lactate catabolism to CO2 in rat tissues.

The current study was initiated in order to compare the rates of oxidative catabolism of D- and L-lactate in various rat tissues. Uniformly labeled D- or L-[14C]lactate was incubated at 37 degrees C in a closed system with tissue homogenates in Krebs-Ringer phosphate buffer. Evolved 14CO2 was trapped in a center well containing a fluted filter paper saturated with strong base and the radioactivity determined. The ratio of L-lactate to D-lactate oxidation was greatest in brain, followed by kidney, heart, and liver. In liver the rate of oxidation of D-lactate exceeded that of L-lactate, in heart the rates were not significantly different and in the other two tissues L-lactate was oxidized more rapidly than D-lactate. These results indicate that the rate of D-lactate catabolism is considerable and is relatively greater than had been reported previously.

Animals↗
PubMed1983

Assay of glyoxalase I in blood.

Glyoxalase I (S-lactoyl-glutathione methylglyoxal-lyase (isomerizing), EC 4.4.1.5) was assayed using alcoholic, acidic 2,4-dinitrophenylhydrazine to follow the disappearance of methylglyoxal over time, with the absorbance of formed methylglyoxal bis-hydrazone measured at 432 nm. Erythrocyte glyoxalase I activities were found to be 64, 41, and 18 mumole of S-lactoyl glutathione formed min-1 X ml-1 of red blood cells in rat, human, and rabbit blood and 174 mumole X min-1 X mg-1 of protein for yeast. The Km values found in millimolar hemimercaptal were about 0.5. Glyoxalase I activity can be determined in crude tissue preparations without interference from biological materials.

Animals↗
PubMedDate not supplied

Water absorption of (RTV) silicone denture soft lining material.

OBJECTIVES: The reason for high water absorption by room temperature vulcanizing (RTV) silicone denture soft lining materials has not been demonstrated previously. An experimental room-temperature vulcanizing (RTV) silicone soft lining material which had been shown to have good mechanical properties had high water absorption at equilibrium whilst losing only small amounts of soluble material after desorption. The volume change in the material was also high. A variety of formulations of the experimental material was devised in order to determine the cause of the high water sorption values. METHODS: Water sorption values were determined using standard experimental techniques. Sections of the polymerized materials were examined by scanning electron microscopy for microporosity. RESULTS: Neither removal of residual cross-linker nor changing the method of polymerization reduced the water absorption. Scanning electron microscopy did not demonstrate a porous structure of the polymerized material. A correlation was seen between filler content and water absorption. A formulation without filler showed a greatly reduced water absorption and volume change. CONCLUSION: It was concluded that the filler was directly responsible for the water absorption of the RTV material.

Absorption↗
PubMedDate not supplied

Wettability of visible light-curing denture lining materials.

PURPOSE: Wetting characteristics of denture lining materials indicate the degree of salivary lubricating effect, which promotes denture retention and patient comfort. This in vitro study investigated the wettability of ten commercially available visible light-cured denture lining materials. MATERIALS AND METHODS: Ten soft and hard visible light-curing materials, one autopolymerized hard lining material, and one autopolymerized denture base material were evaluated for wettability. Wettability was estimated by measuring the equilibrium and hysteresis contact angles using the dynamic contact angle analysis, or Wilhelmy, technique. RESULTS: The equilibrium contact angle ranged from 59.9 to 77.3 degrees, and contact angle hysteresis ranged from 14.7 to 30.6 degrees. CONCLUSION: Visible light-curing lining materials exhibit wetting properties similar to the conventional hard lining and denture base materials.

Acrylic Resins↗