We determined selenium concentrations and activities of the selenoenzyme, glutathione peroxidase (EC 1.11.1.9), in the plasma and erythrocytes of 38 apparently healthy women. We determined selenium concentrations directly by polarized Zeeman-effect flameless atomic absorption spectroscopy. Within-run precision studies for the assays gave CVs of 5.6% for a mean erythrocyte selenium concentration of 149.9 (SD 8.3) microgram/L (n = 10) and 6.4% for a mean plasma selenium concentration of 97.3 (SD 6.2) microgram/L (n = 12). For the women, mean selenium concentrations were 141.4 (SD 14.3) microgram/L of erythrocytes [0.49 (SD 0.07) microgram/g of hemoglobin and 96.3 (SD 14.2) microgram/L of plasma. Glutathione peroxidase activities were measured by a modification of the method of Paglia and Valentine (J. Lab. Clin. Med. 70: 158--169, 1967). Within-run precision studies for the glutathione peroxidase assays gave CVs of 12.8% for mean erythrocyte glutathione peroxidase activity of 77.2 (SD 9.9) U/g of hemoglobin (n = 13), and 8.1% for mean plasma activity of 312.5 (SD 25.2) U/L (n = 11). Mean enzyme activity was 78.7 (SD 12.9) U/g of hemoglobin for erythrocytes and 424 (SD 40) U/L for plasma. Erythrocyte selenium concentrations and glutathione peroxidase activities were positively, but poorly, correlated (r = 0.41, p less than 0.01).

The oxidation products of selenomethionine (SeMet) have been studied via experimental (77)Se NMR and theoretical (77)Se chemical shifts. Four signals are observed: a diastereomeric pair of selenoxides at 840 ppm and two unidentified resonances at 703 and 716 ppm. Theoretical DeltaG and chemical shifts suggest the 703 and 716 ppm resonances correspond to hypervalent selenium heterocycles, called selenuranes, formed by reaction with the amine or acid group of the amino acid and the selenoxide. To identify which of these selenuranes is formed, the amine and acid groups were individually protected. The N-formyl SeMet formed only the selenoxide pair at 840 ppm. The oxidized SeMet methyl ester produced signals at 703 and 716 ppm which are assigned as the Se-N selenurane.

No abstract

No abstract

No abstract

No abstract

Acrosin, a neutral proteinase, is located within the acrosome. The aim of this study was to evaluate acrosin concentrations in patients with severe damage of the sperm head and to determine whether acrosin concentration could predict the chances of fertilization in an IVF program. Sixty patients were accepted into this study, prospectively. The patients were divided into two groups, those with a normal morphology of less than 14% (group I, n = 33) and those with normal morphology less than 14% (group II, n = 27). All patients had a sperm concentration of less than 20 million sperm/ml and less than 30% progressively motile sperm. The acrosin assays were performed on the semen sample obtained on the day of IVF. Routine IVF insemination procedures were used, and only mature oocytes were considered. The only factor that showed a significant correlation of fertilization was normal morphology (p less that 0.01). The mean acrosin level was 73.4 /+- 38.6 mED/10 million sperm in group I and 70.9 /+- 42.7 mIU/10 million sperm in group II (no significant difference). The fertilization rate in group I was 45.4% and in group II, 77.7% p less than 0.002). Acrosin levels were not significantly different in patients with and without fertilization (72.0 /+- 42.1 and 73.6 /+- mIU/10 million sperm, respectively).

We describe methods for determination of manganese in whole blood and serum with Zeeman-effect flameless atomic absorption spectroscopy. These analyses are performed on a twofold or fourfold dilution of the specimen in Triton X-100, 1 g/L. No predigestion or extraction procedures are required. The method of standard additions was used for quantitation. Within-run coefficients of variation for whole-blood manganese were 7.0 and 5.5% for 2.29 and 5.67 micrograms/L, respectively. For determination of serum manganese, coefficients of variation were 10.3 and 5.3% for 0.97 and 3.01 micrograms/L, respectively. Manganese detection limits for the assays were 3.0 pg. Whole-blood manganese concentrations, determined for 60 subjects, yielded a mean (+/- SD) of 9.03 (+/- 2.25) micrograms/L. Mean serum manganese concentration, determined for 20 subjects, was 1.82 (+/- 0.64) microgram/L. No correlation was found between blood manganese concentrations and age, sex, or smoking status.