When salt-stored human oocytes were inseminated in the regular mBWW medium and examined 6 hr later, the zonae of almost all of the oocytes were penetrated by spermatozoa. In contrast, none of zonae were penetrated when the oocytes were inseminated in either Ca2+-free, K+-free or glucose-free medium. The failure of zona penetration by spermatozoa in Ca2+-free and K+-free media is likely to be due to the inhibition of the acrosome reaction. Spermatozoa were unable to exhibit hyperactivated motility in glucose-free medium, suggesting that the failure of zona penetration in this medium is due, at least in part, to the inhibition of hyperactivated motility of spermatozoa.calcium ; potassium ; glucose ; sperm ; zona pellucidaUnder normal conditions mammalian spermatozoa must pass through the zona pellucida before effecting fertilization.Proper interaction of sperm molecules with the complementary zona molecules, strong flagellar motion of the spermatozoa and ionic balance of the medium are all essential for successful penetration of spermatozoa through the zona pellucida (O'Rand et al. 1986;Yanagimachi 1988;Saling 1989;Wassarman 1990). We report here that human spermatozoa are unable to attach to and penetrate through the zona unless the medium contains millimolar concentrations of Ca2+, K+ and glucose. MATERIALS AND METHODS MediaThe standard medium used in this study was a modified Krebs-Ringer's solution, mBWW (Overstreet et al. 1980) containing 35 mg/ml human serum albumin (HSA ; Sigma Chemical Co., St. Louis, MO, USA). This medium had an osmolality of 308 mOsmol and pH value of 7.5±0.1 when equilibrated with 5% CO2 in air. Ca2+-free, Mg2+-free, glucosefree, lactate-free and pyruvate-free media were prepared by replacing CaC12i MgSO4, glucose, Na-lactate and Na-pyruvate, respectively, with appropriate amounts of NaC1 to keep the osmolality of the media constant. K+-free medium was prepared by replacing KCl and KH2 PO4 with NaCI and NaH2 PO4 i respectively. The pH of these media was adjusted, if necessary, to 7.5 by adding a small quantity of 1 M HC1 or NaOH. All media were

Estriol prevented postmenopausal bone loss and improved climacteric symptoms effectively with low incidence of genital bleeding.

The calcaneus bone mineral density of 473 Japanese women was measured by single energy X-ray absorptiometry (SXA) and the vertebrae bone mineral density of 198 Japanese women was measured by dual energy X-ray absorptiometry (DEXA). The calcaneus bone mineral density of Japanese women starts decreasing from age 30, and the rate of decrease accelerates from the age of 50. The vertebrae bone mineral density starts decreasing from the age of 35, and a conspicuous decrease can be seen from the age of 50 as well. Because bone deterioration of Japanese women is thought to start earlier than Caucasian, the necessity of osteoporosis screening before menopause was suggested. A high positive correlation (r = 0.804) between calcaneus bone mineral density and vertebrae bone mineral density was found, and a high degree of precision of SXA was shown.

The calcaneus bone mineral density values (BMDs) of healthy Japanese women peaked at 20 to 25 years of age with 435 ± 66 mg/cmz (mean± S.D. ), decreased 0.51% on the average every year thereafter until 45 years of age, 1.72% between 45 and 55 years (menopause) and 0.55% thereafter. The vertebrae bone mineral density value peaked at 30 to 35 years of age with 1.06±0.13 g/cmz (mean ± s.D. ), decreased 0.67% on the average every year thereafter until 45 years of age, 1.23% between 45 and 55 years (menopause) and 0.70% thereafter. Mean -2.0 s.D. of the peak bone mass was considered appropriate as the fracture threshold for both the calcaneus and vertebra, judging from the BMDs of osteoporosis patients.bone mineral density; fracture threshold; osteoporosis; single energy x-ray absorptiometry; dual energy x-ray absorptiometry Osteoporosis is a serious disease that occurs frequently among women of advanced age. Since osteoporosis is a disorder characterized by skeletal fragility due to a quantitative loss of bone mineral or architectural changes that diminish the strength of bone, accurate measurement of the bone mineral density values (BMDs) is necessary for diagnosis and prevention. However, there is no established theory as to when the danger of osteoporosis arises at what degree of decrease in the BMDs. For the purpose of setting the BMDs level at which prophylactic treatment against osteoporosis must be started, the calcaneus BMDs was measured by single energy x-ray absorptiometry (SXA) and the vertebrae (L2-L4) BMDs by dual energy x-ray absorptiometry (DEXA) among Japanese women. The high accuracy of these two measuring methods was already established in the previous study (Hoshi et al. 1993). MATERIALS AND METHODSUsing healthy women in ages ranging from 20 to 75 years old as the subjects, the calcaneus BMDs in 440 women and lumbar vertebrae (L2-L4) BMDs in 233 women were measured by SXA and DEXA, respectively.

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