During the winter and spring of 1952-53 a survey of hemoglobin values was made in Halifax among 1308 male subjects 6 to 98 years of age, and 1424 female subjects 6 to 94 years of age. Among children 6 to 14 years old the values increased from about 13 to about 14 Gm. per 100 ml. of blood, and there were essentially no differences between the sexes. The average value for both the boys and the girls was 13.5 Gm. In girls between 14 and 20 years of age the hemoglobin values decreased slightly, reaching about 13 Gm. per 100 ml. In boys of corresponding ages there was an increase to about 15 Gm. In both sexes these values were attained at about 20 years of age, and remained characteristic of the third decade of life. They were essentially the lowest and the highest shown respectively by the female and the male subjects of any age group. Hemoglobin values in men between 20 and 60 years of age were typically 14.5 to 15 Gm. per 100 ml., the higher values tending to occur among the younger men. After the fifth decade there were progressive and marked decreases to an average of 12.4 in men between 80 and 90 years of age. In women from 20 years of age onward the average hemoglobin values remained near 13 Gm. per 100 ml.
At levels of 2–20% in the diet of young rats, carrageenan is quantitatively excreted in the faeces.In diets fed in equal amounts, both cellulose and carrageenan, when substituted for starch in various proportions, affect the growth of young rats. Beginning at levels of 10–15%, however, growth is slower with carrageenan, and there is less absorption of dietary nitrogen,Carrageenan, like cellulose, has no nutritional value. The depression of nitrogen absorption could explain the slower growth rate that occurs with carrageenan in the diet.
Waisman (1944) observed that marked anaemia developed in monkeys in riboflavin deficiency. Wintrobe, Buschke, Follis & Humphreys (1944) observed anaemia in riboflavin deficiency in the pig, but Terrill, Ammerman, Walker, Edwards, Norton & Becker (1955) did not. Axelrod, Lipton & Elvehjem (1941) found no anaemia in dogs in riboflavin deficiency, whereas Spector, Maass, Michaud, Elvehjem & Hart (1943) observed mild anaemia, which became severe if the animals were subjected to slight haemorrhage. Gyorgy, Robscheit-Robbins & Whipple (1938) studied the regeneration of haemoglobin in dogs made anaemic by an inadequate diet, when repletion was stimulated by haemorrhage, and found that the production of haemoglobin was increased by the addition of more riboflavin to the diet. Working with rats, Carpenter & Kodicek (1952) found only insignificant anaemia in riboflavin deficiency. Endicott, Kornberg & Ott (1947)~ Shukers & Day (1943) and Kornberg, Tabor & Sebrell(1945-6) found that anaemia developed only occasionally in the rat in riboflavin deficiency. Kornberg et al. (1945-6) carried their investigation further by studying the haematopoietic process stimulated by haemorrhage. As the result of repeated haemorrhage the haemoglobin and haematocrit values fell, the former to a greater extent than the latter, and consequently there was a decrease in the mean corpuscular haemoglobin concentration. These values eventually levelled off in the control animals, but continued to fall in those deficient in riboflavin. Only haematocrit values were measured during recovery from repeated haemorrhage. In the riboflavin-deficient animals they fell lower and did not rise to the same extent as in the controls. The authors interpreted the results of their experiments as indicating that riboflavin deficiency impaired the process of regeneration of red cells and haemoglobin. Their results, however, do not fully support this conclusion because red-cell counts were not done, but they do indicate some type of impairment in the haematopoietic process. There is evidence, therefore, that in the rat riboflavin is involved in haematopoiesis, which becomes evident only when a stress is put upon the system, as by severe haemor-* Issued as N.R.C. no. 5680. Presented in part at the zrst Annual Meeting of the Canadian Physiological Society in Ottawa in June 1957, and at the zxst International Congress of the Physiological Sciences in Buenos Aires in August 1959.
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