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P Snow

Publications and source records attributed to P Snow.

26 records · Page 2Linked to original sources
PubMed1981

Biochemical studies of the human thymocyte cell-surface antigens T6, T9 and T10.

Three human thymic cell-surface antigens T6, T9 and T10, previously defined by monoclonal antibodies, were analyzed using immunoprecipitation techniques. The antigen T6 was found to be a 49,000 dalton glycoprotein, which is associated with beta 2-microglobulin, the small subunit (12,000 daltons) of the HLA-A, -B, and -C antigens. The target antigen for the monoclonal reagent anti-T9 was found to be a glycoprotein of 94,000 daltons, which appears as a disulfide-linked dimer of 190,000 daltons on the cell surface. The antigen precipitated by the anti-T10 antibody is a 45,000 dalton glycoprotein. We present preliminary evidence that all three cell-surface proteins may be integral membrane proteins. These findings, in addition to the distribution patterns, suggest that the T6 antigen is the human homolog of the murine thymus leukemia (TL) antigen.

Antigens, Surface↗
PubMed1981

Rate of starch hydrolysis in vitro as a predictor of metabolic responses to complex carbohydrate in vivo.

This study was designed to determine whether the rate of hydrolysis of different starches by pancreatic amylase in vitro was proportional to the postprandial glucose and insulin response to those starches after oral ingestion. Lean young men consumed four test meals of rice containing 75 g starch: white rice, unpolished (brown) rice, ground white rice, and ground brown rice. Postprandial glucose and insulin responses were measured over 4 h and showed the following pattern: ground white rice congruent to ground brown rice greater than white rice greater than brown rice. The maximum increases in blood glucose after the four meals were brown rice 0.9 mM, white rice 1.5 mM, ground brown rice 3.3 mM, and ground white rice 3.6 mM. Samples of the cooked rices were incubated in vitro with pancreatic amylase for 30 min and the percentage starch hydrolysis determine. The relative rates of starch hydrolysis correlated very closely with the peak glucose responses: brown rice 17.6%, white rice 30.8%, ground brown rice 68.2% and ground white rice 71.8%. These results indicated that the rate of intestinal hydrolysis of starch is an extremely important determinant of the metabolic responses to a particular starch. The rate of starch hydrolysis can be determine simply by an in vitro method and should assist the design of diets for the treatment of diabetes.

Amylases↗
PubMed1981

Factors affecting the rate of hydrolysis of starch in food.

After accurate determination of the content of available carbohydrate in a wide variety of cereals, as in vitro method was used to study factors that influence hydrolysis rates of starch in foods. Fiber, physical form, cooking, and the possible presence of a natural amylase inhibitor were all shown to affect hydrolysis rates of starch. Fiber only exerted an inhibiting effect on the rate of hydrolysis when it formed a physical barrier to limit access of the hydrolytic enzymes to the starch (as in whole brown rice, for example). Particle size played an important role in determining the rate of hydrolysis. Cooking made the starch much more readily available for enzymic hydrolysis presumably by gelatinizing it. Stoneground wholemeal flour was hydrolyzed more slowly than white flour. This is consistent with the presence of a natural amylase inhibitor that has been isolated from wheat germ in the whole grain. Our results suggest that such amylase inhibitor activity is destroyed by passage through the roller mill, since the starch in wheat germ and standard wholemeal flour (i.e., not stoneground but reconstituted after passage through the roller mill) was hydrolyzed at a rate identical to white flour.

Amylases↗