The modulation of transcobalamin II (TC-II) production by cyclic adenosine 3',5'-monophosphate in the murine macrophage cell line J774: relationship to growth behavior.

We undertook a study to define the role of cyclic AMP [cAMP] in modulating the secretion of transcobalamin II (TC-II) in the mouse macrophage like cell line J774. J774 was observed to secrete large amounts of TC-II, particularly in the presence of 8-bromo cAMP or cholera toxin or when grown in medium supplemented with low concentrations of horse serum (1% or 5%) or in serum-free medium. Variant cell lines derived from J774 and deficient either in adenylate cyclase (ac -) or cAMP-dependent protein kinase (pk -) activity showed very low and intermediate levels of basal secretory activity of TC-II, respectively, compared to J774.

Serum transcobalamin levels as an early indicator of bone marrow engraftment following transplantation.

Three B12 binding proteins, the transcobalamins TCI, TCII and TCIII, were determined serially in the serum of five patients who underwent bone marrow transplantation. The increase in TCII, followed by the increase in TCI, proved to be an early indicator of bone marrow regeneration, reaching a peak of up to twice its normal levels at least 5 d prior to the rise of the peripheral white blood cell count.

Prognostic significance of changes in serum transcobalamin levels in cancer patients with chemotherapy-induced granulocytopenia.

Serum transcobalamin (TC) levels were determined daily in 14 adults suffering from advanced nonhematological malignancies and hospitalized because of chemotherapy-induced leukopenia and fever. Even during the nadir leukocyte count, TCI and TCIII serum levels were normal or only slightly decreased indicating that bone marrow activity was not completely suppressed. A significant increase in serum TCII level was observed in all patients, with peak values occurring an average of 4.

Effect of dexamethasone on serum transcobalamin II concentration in women undergoing pelvic surgery.

Dexamethasone (120 mg/day for 2 days) was administered intramuscularly to young females undergoing pelvic surgery for infertility. The therapy was shown to cause a transient increase in the serum level of the granulocyte-produced transcobalamins (TCI and TCIII) and more significantly in the monocyte-produced transcobalamin (TCII), from 1220 +/- 70 to 1980 +/- 158 pg/ml (P less than 0.001).

Production of transcobalamin II by various murine and human cells in culture.

The ability of various murine and human cell types to secrete in vitro transcobalamin II (TCII), the vitamin B12 transport protein, was investigated. All cell types tested were found to secrete into the culture medium biologically active TCII molecules, capable of facilitating B12 uptake. The largest amounts of TCII were produced by primary cultures of murine fibroblasts and macrophages.

Serum transcobalamin II levels in breast carcinoma patients.

Serum levels of transcobalamin II (TCII) were determined in 139 patients with breast carcinoma. The patients were divided into two groups. Group A consisted of 74 patients with no evidence of active disease at the primary site or in complete remission.

The transcobalamins in polycythaemia vera.

The unsaturated B12 binding capacity (UBBC) of the serum and the binding capacity of each of the 3 vitamin B12 binders--the transcobalamins (TC) I, II and III were determined in 21 patients with polycythaemia vera (PV) during the course of the disease and following treatment, using the recently described charged cellulose filter technique. High serum UBBC due to elevated serum TCIII was found in all patients. TCI was moderately elevated in patients who had leucocytosis with a shift to the left.

The synthesis of transcobalamin II, a vitamin B12 transport protein, by stimulated mouse peritoneal macrophages.

The concentration of transcobalamin II (TCII), the vitamin B12 binding protein which delivers vitamin B12 to the tissues, was determined in stimulated and non stimulated mouse peritoneal exudate cells (PEC). Following a single intraperitoneal thioglycollate injection there was a marked increase in TCII which was shown to be produced by the adherent cells of the PEC i.e.

Nutritional survey in an iron- and folate-deficient population.

A high prevalence of folate and iron-deficiency anemia was found in women and children of Kiryat Shmoneh, an Upper Galilee community. Malnutrition was assumed to be partially responsible for these deficiencies. To verify this assumption, a detailed nutrition survey was carried out in 30 families, comprising 232 individuals in this community.

Serum and erythrocyte folates in combined iron and folate deficiency.

A high incidence of iron and folate deficiency was found in 80 female subjects living in a private institution. Iron therapy in individuals with low serum iron values resulted in a significant increase in hemoglobin levels. An improvement in serum and RBC folate levels was also found following iron therapy but this could not be attributed to treatment since a similar increase was observed in untreated control subjects, probably due to an increased dietary intake of folates during the study period.

Utilization of yeast polyglutamate folates in man.

Ingestion by healthy humans of small amounts of polyglutamate folates from yeast, equivalent to 300 mug of monoglutamate folate and containing 30 mug of "free folate," resulted in an appreciable elevation of the serum folate corresponding to 300 mug of synthetic pteroylmonoglutamate (PGA). Ingestion of higher amounts of polyglutamate folate did not result in higher serum folate elevations than did 300 mug. It is concluded that small amounts of polyglutamate folate from yeast are fully utilized, presumably by deconjugation in the gut prior to absorption.