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P Snow

Publications and source records attributed to P Snow.

7 recordsLinked to original sources
PubMed1983

Comparison of target antigens of monoclonal reagents OKT5, OKT8, and Leu2A, which inhibit effector function of human cytotoxic T lymphocytes.

The OKT8 antigen, which is present on a subset of thymocytes and peripheral blood T lymphocytes, was examined utilizing a variety of biochemical techniques. It is shown to be a glycoprotein of 34 kD molecular weight which contains a hydrophobic region. Further, under nonreducing conditions, dimers of 76 kD and 67 kD are found. These species are most likely generated by differences in internal disulfide bonding. When two previously described antigens, OKT5 and Leu2A, were compared with OKT8, no structural differences could be found among the three antigens. Evidence is presented, however, which indicates that the three monoclonals recognize different epitopes on the molecule. Functional analysis on cytotoxic T lymphocyte (CTL) clones confirmed the biochemical findings concerning the identity of the three proteins.

Antibodies, Monoclonal↗
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↗