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Biomedical subjects

I Chanarin

Publications and source records attributed to I Chanarin.

At least 163 records · Page 9Linked to original sources
PubMed1972

Role of third serum vitamin B 12 binding protein in vitamin B 12 transport.

A third vitamin B(12) binding protein present in normal serum has been shown to participate in transport of labelled vitamin B(12) absorbed from the gut. All three vitamin B(12) binding proteins in serum were labelled at the same time after oral administration of vitamin B(12), implying that "free" vitamin B(12) reached the portal blood from the gut mucosa.

Biological Transport↗
PubMed1972

Toxicity of trimethoprim-sulphamethoxazole in patients with megaloblastic haemopoiesis.

Four consecutive patients with megaloblastic anaemia who also received therapy with trimethoprim-sulphamethoxazole all showed poor responses to specific haematinic therapy. This was attributed to trimethoprim, which suppressed reticulocyte responses in three cases and produced a pancytopenia in two and a falling haemoglobin with neutropenia in a third. A fourth patient, with pernicious anaemia, had a satisfactory reticulocyte response but experienced no clinical benefit until after withdrawal of trimethoprim.Trimethoprim seems not to be a safe form of therapy in patients with a megaloblastic process; many of the toxic reactions reported with this drug may be on the basis of an unrecognized megaloblastic form of haemopoiesis.

Adult↗
PubMed1972

Observations on folate absorption with particular reference to folate polyglutamate and possible inhibitors to its absorption.

A test system for detection of inhibitors to the enzyme which removes the glutamic acid peptide chain from folate polyglutamates (folate conjugase) is described. This utilizes the reaction between plasma conjugase and the folate polyglutamate in red blood cell haemolysate. Diphenylhydantoin and yeast extracts did not inhibit plasma conjugase. The better absorption of monoglutamate forms of folate as compared to polyglutamate forms was confirmed. Polyglutamates were absorbed normally by patients with pernicious anaemia, suggesting that conjugase enzymes (optimally active at pH 4.5) did not normally function to a significant extent in the gut lumen. Diphenylhydantoin and bicarbonate did not interfere with absorption of either mono- or polyglutamate forms of folate.

Anemia, Pernicious↗
PubMed1971

Further observations on the relation between iron and folate status in pregnancy.

This study was planned to determine whether iron deficiency in pregnancy predisposed to the development of folate deficiency and also the smallest daily iron supplement that maintained haemoglobin levels in pregnancy.Three groups of women were given oral ferrous fumarate supplying 30, 60, and 120 mg of iron; a fourth group was given 1 g of parenteral iron in early pregnancy followed by oral iron (60 mg); a fifth group received a placebo. Tablets were taken once daily.Oral iron 30 mg once daily maintained haemoglobin levels throughout pregnancy. Women whose marrows lacked demonstrable iron at the 37th week had a significantly higher incidence of megaloblastic haemopoiesis (28.7%) than those with demonstrable iron stores (15.3%); women taking oral iron did not have a lower frequency of megaloblastosis than those given a placebo. We concluded that iron does not have a direct effect on folate status in pregnancy, that the association of iron deficiency and megaloblastic anaemia in pregnancy is the result of poor nutrition, and that there is no cause-and-effect relation between them.

Anemia, Hypochromic↗
PubMed1971

Intrinsic-factor antibody and absorption of vtiamin B12 in pernicious anaemia.

The mean urinary excretion in a vitamin-B(12) absorption (Schilling) test in control subjects was 19.2% and in pernicious anaemia when given with additional intrinsic factor was as follows: no intrinsic-factor antibodies demonstrable 19.3%, antibodies in serum only 14.4%, antibodies in gastric juice only 11.1%, and antibodies in both serum and gastric juice 8.4%. It is concluded that intrinsic-factor antibody exerts an adverse effect on vitamin-B(12) absorption in most patients with pernicious anaemia.

Anemia, Pernicious↗