Difference In Hemoglobin Concentration Research Articles

Hematological changes in deer mice acclimated at different ambient temperatures.

Deer mice ( Peromyscus maniculatus and Peromyscus leucopus) were acclimated at temperatures of 5° ±0.5°C and 30°±0.5°C for various intervals with periods at 20°±0.5°C preceding the cold and warm acclimation periods. Hemoglobin concentrations, hematocrits and erythrocyte diameters were measured on a group of nonsplenectomized mice and on another group of splenectomized mice which were subjected to similar temperature conditions. It was found that there were significant increases in hemoglobin and hematocrit values with acclimation at 5°C, which were more marked in the splenectomized mice. Differences in hemoglobin concentrations and hematocrits were significant between 5° and 30°C, but differences were not as apparent between mice at 30°C and those exposed at 20°C. There were no significant changes in erythrocyte diameters, although the mean corpuscular hemoglobin concentration was significantly lower in all of the splenectomized mice as opposed to the nonsplenectomized ones. It is suggested that splenectomy in some way enhances erythopoiesis in response to low temperature since there was no significant difference in hematocrits of nonsplenectomized and splenectomized mice exposed at 20°C prior to cold acclimation.

EFFECTS OF EARLY FEEDING OF STRAINED MEAT TO PREMATURELY BORN INFANTS

This study was undertaken to determine the effect on prematurely born infants of the feeding of strained meat. One group of infants received a standard formula; another an identical formula to which strained meat was added, and a third group was breast fed. Meat added to the diet of prematurely born infants weighing between 2000 and 6750 gm. was well accepted. There was no significant difference in the symptoms or signs of illness among the infants of either of the three groups. It was found that a plot of the body weight of such infants against age generally gives a smooth sigmoid curve. The central portion of the "S" forms a remarkably straight line. The linear portion of the curve is located in the interval between 2500 and 4500 gm. body weight. The location is relatively unaffected by either age or birth weight. The slope of this linear portion was taken as the measure of the weight gain. A similar relationship was found for the crown-heel length. These findings are not only of academic interest but are also of practical importance since they provide an unusually good tool for further nutritional and other studies. Growth as measured by rate of change of weight and length did not differ significantly between the experimental group and the control group. The breast-fed group exceeded the experimental and control groups in both weight and length gain. The greater weight gain in the breast-fed group as compared to the experimental group was statistically significant. Minimum values for red blood cell count and hemoglobin were observed at 12 weeks of age. These values rose steadily until about 20 weeks of age, at which time they became relatively stable. There was no significant difference in the hemoglobin concentration or red blood cell count between the three groups at 12 weeks of age. At 20 weeks, however, the meat-fed or experimental group exceeded the control by a significant amount. The mean difference in hemoglobin concentration of the experimental group and that of the control group was 1.0 gm./100 cc. This finding is of interest especially since the experimental and control groups both received more than adequate amounts of iron added to the diet. A gradual rise in serum protein concentration was noted with increasing age. At 12 weeks of age, the serum protein concentration for the breast-fed group was significantly lower than that for the experimental group, the average difference being 0.40 gm./100 cc. The average difference between these two groups at 20 weeks was 0.35 gm./100 cc. but there were too few in the breast-fed group at this time to give the difference statistical significance. The serum protein concentrations in the experimental and the control groups did not differ significantly at either 12 or 20 weeks of age. Analysis of the total volume intake of the formulae showed that intake of the experimental group was reduced in proportion to the greater caloric content of the meat-containing formula. The result was that the daily intake of calories was the same in both the experimental group and the control group. This remarkable reduction in volume of intake by premature infants in the weight groups concerned and the strikingly uniform caloric intake are of interest particularly in view of current thoughts on self selection of diet. No differences were noted in the weight or length gain, hemoglobin, red blood cell count, or serum protein concentration between the experimental group and the control group when the infants reached one year of age.