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C A Finch

Publications and source records attributed to C A Finch.

209 records · Page 12Linked to original sources
PubMedDate not supplied

Interactions of iron deficiency, anemia, and thyroid hormone levels in response of rats to cold exposure.

We have earlier shown that iron-deficient rats have increased urinary norepinephrine (NE) excretion. They also have an exaggerated rise in urinary NE when placed in the cold, a stimulus known to cause increased NE excretion in normal rats. Nonetheless, they fall to maintain body temperature. We have now examined the thyroidal response to cold in iron-deficient rats. As others have shown, control rats had a rise in plasma levels of thyroxine (T4) and triiodothyronine (T3) soon after entering the cold environment (4 degree C); they also maintained a rectal temperature above 36 degree C. In the iron-deficient rats, basal levels of T3 and T4 were normal, but there was little or no increase after 6 hr in the cold, and, as before, body temperatures fell. Injections of T3, 10 microgram/kg, 15 min before cold exposure improved the ability of iron-deficient rats to maintain body temperature, but they still did not do as well as the controls. We conclude that the inability of iron-deficient rats to increase T3 levels after cold exposure is one factor in their poor resistance to cold. The defect could involve inability to augment thyroid secretion, imparied ability to convert T4 to T3 in peripheral tissues, or both. Preliminary data suggest that anemia is an important and perhaps critical factor in the cold sensitivity of iron deficiency. Transfusing iron-deficient rats from their usual hematocrit of 15-20 to one of 30 restores cold resistance to normal. Transfusion also allows a more normal thyroid response, with a rise in T3 and T4 levels, so thyroid hormones may be a factor in the improvement produced by transfusion.

Anemia, Hypochromic↗
PubMedDate not supplied

Iron balance in superdonors.

Volunteers who are able to donate blood frequently without becoming anemic provide a unique opportunity to observe iron balance under conditions of controlled blood loss. The 88 men and 88 women studied had given a mean of 17 donations (range 10-24) over 4 years. Twenty-seven percent of men and 45 percent of women took iron-containing supplements. In these "superdonors," estimated iron loss averaged 3.8 mg/day in men, 3.4 mg/day in menstruating women and 3.0 mg/day in nonmenstruating women. Dietary iron consumption estimated from the dietary history averaged 17 mg/day for men and 13 mg/day for women; in general, the superdonors consumed a superior diet. Sixty-three percent of the unsupplemented individuals had ferritin values less than 20 micrograms/l. Assuming that stores were constant, these individuals would have to absorb 25 percent of their dietary iron to meet total iron loss. Supplemented men and women taking an average of 24 and 34 mg of additional iron per day, respectively, showed relatively little difference in iron balance from unsupplemented individuals; 58 percent had serum ferritin values of less than 20 micrograms/l, and 28 percent were equal to or less than 12 micrograms/l. The low level of absorption (6-9%) in supplemented individuals suggests that the iron availability of iron-containing preparations ingested may have been poor.

Adult↗
PubMedDate not supplied

Supplementation of total parenteral nutrition solutions with ferrous citrate.

Daily infusion of a total parenteral nutrition (TPN) formulation containing 1 liter of 5.5% Travasol provides less than 0.1 milligrams of iron. By comparison, a formulation which includes a liter of 10% Travamin provides 2 milligrams of iron per day. To meet iron requirements in patients infusing formulations containing Travasol, iron was added as ferrous citrate. In in virto experiments, 74% of this iron was available to transferrin. In seven patients in whom in vivo availability was tested by red cell incorporation, the mean availability was 81%. Ferrous citrate is recommended as a safe, effective additive to TPN solutions for adult patients requiring iron supplements.

Adult↗