Magnesium metabolism in blood and the whole body in man using 28magnesium.

Studies of magnesium kinetics in plasma, red cells, and the whole-body with ²⁸Mg are described. The observations in plasma were analyzed with a three-compartment model and those in red cells with a two-compartment model. An integral approach, using the occupancy principle, was used in the analysis of the whole-body observations. At 120 hr after intravenous administration of ²⁸Mg, exchangeable magnesium calculated by the dilution principle was only 23% of total body magnesium. There was good agreement between the estimates of exchangeable magnesium based on plasma and “spot” urine ²⁸Mg activity. Exchangeable magnesium, as estimated by compartmental analysis and the occupancy principle, was only 12.5%–15% of total body magnesium. These results suggest the existence of magnesium compartments in the body with turnover half-periods of at least 63–181 days that cannot be investigated adequately with the short-lived tracer, ²⁸Mg. A possible mechanism for the observed pattern of red cell uptake of ²⁸Mg in vivo is suggested in which magnesium enters these cells only during erythropoiesis and is then lost progressively from circulating red cells during the aging process. Present results suggest that the concentration of magnesium in reticulocytes may be 3.9 times greater than the mean red cell concentration. Magnesium may leave red cells exponentially with age; a half-period of 22.4 days is suggested.     

Does the home environment and the sex of the child modify the adverse effects of prenatal exposure to chlorpyrifos on child working memory?

Prenatal exposure to chlorpyrifos (CPF), an organophosphorus insecticide, has long been associated with delayed neurocognitive development and most recently with decrements in working memory at age 7. In the current paper, we expanded the previous work on CPF to investigate how additional biological and social environmental factors might create or explain differential neurodevelopmental susceptibility, focusing on main and moderating effects of the quality of the home environment (HOME) and child sex. We evaluate how the quality of the home environment (specifically, parental nurturance and environmental stimulation) and child sex interact with the adverse effects of prenatal CPF exposure on working memory at child age 7years. We did not observe a remediating effect of a high quality home environment (either parental nurturance or environmental stimulation) on the adverse effects of prenatal CPF exposure on working memory. However, we detected a borderline significant interaction between prenatal exposure to CPF and child sex (B (95% CI) for interaction term=-1.714 (-3.753 to 0.326)) suggesting males experience a greater decrement in working memory than females following prenatal CPF exposure. In addition, we detected a borderline interaction between parental nurturance and child sex (B (95% CI) for interaction term=1.490 (-0.518 to 3.499)) suggesting that, in terms of working memory, males benefit more from a nurturing environment than females. To our knowledge, this is the first investigation into factors that may inform an intervention strategy to reduce or reverse the cognitive deficits resulting from prenatal CPF exposure.     

Inhalation of Tetramethyllead and Tetraethyllead

In a study of the specificity of the iodine-azide reaction in carbon disulfide (CS₂) exposure, iodine-azide reaction and dithiocarb (sodium diethyidithiocarbamate) in the urine of alcoholics treated with disulfiram (tetraethylthiuram disulfide) were determined.

After application of disulfiram, the iodine-azide reaction was negative 40% of the time, but some dithiocarb is always present in urine. Therefore, dithiocarb determination could be used to measure the patient’s discipline.

The great dispersion of dithiocarb results is discussed as a possible influence of pathologic condition and compared with other drugs, especially, meprobamate.

The application of meprobamate increased the percentage of positive iodine-azide reaction in disulfiram, treated alcoholics, but dispersion of dithiocarb results was the same as in alcoholics not using meprobamate.

The iodine-azide test (IAT) does not provide a satisfactory index of exposure in individuals taking disulfiram for alcoholism.     

Collection of peripheral blood stem cells in newly diagnosed myeloma patients without any prior cytoreductive therapy: the first step towards an 'operational cure'?

We have shown that primary therapy with non-myeloablative (140 mg/m(2)) high-dose melphalan (HDM) without hematopoietic support results in high response rates in untreated myeloma and very long-term survival of some patients. This study was designed to see if sufficient CD34 (+) cells can be harvested at presentation in newly diagnosed patients to administer myeloablative HDM (200 mg/m(2); HDM200) with autograft as primary therapy. This may improve outcome by rapid achievement of complete remission (CR) and possible avoidance of late myelodysplasia as a consequence of non-transplant induction chemotherapy. Thirty untreated patients received 1 g/m(2) methylprednisolone daily (days 1-6) and 12-16 micro g/kg G-CSF daily (days 3-6), and underwent leukapheresis on days 6 and 7. The median CD34(+) cell yield was 1.31 x10(6)/kg (range, 0.23-5.63), and was > or =1 x10(6)/kg in 73%. Cell yields were significantly lower than in 82 historical controls apheresed after completion of induction chemotherapy (median 2.16 x 10(6)/kg), and improved in patients who were apheresed again after induction chemotherapy. Three patients received primary therapy with HDM200 and autograft using these cells and attained CR. We conclude that it is possible to harvest stem cells in three-quarters of untreated myeloma patients. Increasing the number of apheresis procedures is needed to improve the number of CD34(+) cells collected.     

Impact of previous high-dose therapy on outcome after allografting for multiple myeloma

We describe a single centre experience of 33 patients allografted for multiple myeloma, of which 28 received matched sibling marrow, one haploidentical family donor marrow and four matched but unrelated donor marrow. Median follow-up after transplant is 27 months, and 13 patients are currently alive. One out of four patients with an unrelated donor survives and 12 out of 28 (42.8%) with matched sibling donors. Four patients were unevaluable because of early death (相似文献