Intact fetal ovarian cord formation promotes mouse oocyte survival and development

Background  

Female reproductive potential, or the ability to propagate life, is limited in mammals with the majority of oocytes lost before birth. In mice, surviving perinatal oocytes are enclosed in ovarian follicles for subsequent oocyte development and function in the adult. Before birth, fetal germ cells of both sexes develop in clusters, or germline cysts, in the undifferentiated gonad. Upon sex determination of the fetal gonad, germ cell cysts become organized into testicular or ovarian cord-like structures and begin to interact with gonadal somatic cells. Although germline cysts and testicular cords are required for spermatogenesis, the role of cyst and ovarian cord formation in mammalian oocyte development and female fertility has not been determined.     

DAZ family proteins exist throughout male germ cell development and transit from nucleus to cytoplasm at meiosis in humans and mice

The human DAZ gene family is expressed in germ cells and consists of a cluster of nearly identical DAZ (deleted in azoospermia) genes on the Y chromosome and an autosomal homolog, DAZL (DAZ-like). Only the autosomal gene is found in mice. Y-chromosome deletions that encompass the DAZ genes are a common cause of spermatogenic failure in men, and autosomal homologs of DAZ are essential for testicular germ cell development in mice and DROSOPHILA: Previous studies have reported that mouse DAZL protein is strictly cytoplasmic and that human DAZ protein is restricted to postmeiotic cells. By contrast, we report here that human DAZ and human and mouse DAZL proteins are present in both the nuclei and cytoplasm of fetal gonocytes and in spermatogonial nuclei. The proteins relocate to the cytoplasm during male meiosis. Further observations using human tissues indicate that, unlike DAZ, human DAZL protein persists in spermatids and even spermatozoa. These results, combined with findings in diverse species, suggest that DAZ family proteins function in multiple cellular compartments at multiple points in male germ cell development. They may act during meiosis and much earlier, when spermatogonial stem cell populations are established.     

H+-pyrophosphatase of Rhodospirillum rubrum. High yield expression in Escherichia coli and identification of the Cys residues responsible for inactivation my mersalyl

H(+)-translocating pyrophosphatase (H(+)-PPase) of the photosynthetic bacterium Rhodospirillum rubrum was expressed in Escherichia coli C43(DE3) cells. Recombinant H(+)-PPase was observed in inner membrane vesicles, where it catalyzed both PP(i) hydrolysis coupled with H(+) transport into the vesicles and PP(i) synthesis. The hydrolytic activity of H(+)-PPase in E. coli vesicles was eight times greater than that in R. rubrum chromatophores but exhibited similar sensitivity to the H(+)-PPase inhibitor, aminomethylenediphosphonate, and insensitivity to the soluble PPase inhibitor, fluoride. Using this expression system, we showed that substitution of Cys(185), Cys(222), or Cys(573) with aliphatic residues had no effect on the activity of H(+)-PPase but decreased its sensitivity to the sulfhydryl modifying reagent, mersalyl. H(+)-PPase lacking all three Cys residues was completely resistant to the effects of mersalyl. Mg(2+) and MgPP(i) protected Cys(185) and Cys(573) from modification by this agent but not Cys(222). Phylogenetic analyses of 23 nonredundant H(+)-PPase sequences led to classification into two subfamilies. One subfamily invariably contains Cys(222) and includes all known K(+)-independent H(+)-PPases, whereas the other incorporates a conserved Cys(573) but lacks Cys(222) and includes all known K(+)-dependent H(+)-PPases. These data suggest a specific link between the incidence of Cys at positions 222 and 573 and the K(+) dependence of H(+)-PPase.     

Effects of gender,diet, exogenous melatonin and subchronic PCB exposure on plasma immunoglobulin G in mink

Effects of different fish-based diets (freshwater smelt, Baltic herring, marine herring/cod offal or their mixtures), gender, beta-glucan supplement, exogenous melatonin, and PCB exposure (Aroclor 1242((R)), 1 mg per animal per day in feed) on plasma immunoglobulin G (IgG) in the mink (Mustela vison) were studied. The aims of the study were to find out whether plasma IgG of the mink is affected by the subchronic PCB exposure, and whether biological, nutritional and hormonal effects are large enough to mask the possible IgG response. The concentration of IgG was determined using enzyme-linked immunosorbent assay (ELISA). Sexual dimorphism was detected, the males having higher levels of plasma IgG. In addition, melatonin tended to decrease IgG in females but not males. Diet also affected the humoral immune arm; the mixed-fish diets caused an unfavorable ratio of the oxidation products of lipids vs. vitamin E in liver, and resulted in low IgG concentration in plasma. In males fed Baltic herring, the beta-glucan supplement also lowered IgG levels. The PCBs failed to affect the plasma IgG of the smelt-fed female mink, and IgG concentration was not correlated with increased hepatic EROD activity or with the decreased total retinol in the liver of exposed mink. It is concluded that hormonal/seasonal and dietary factors affect the plasma IgG levels to such an extent that possible change in plasma IgG level due to PCBs in wild populations of mink is difficult to detect without a large amount of reference data.     

The Finnish Disease Heritage III: the individual diseases

This article is the third and last in a series entitled The Finnish Disease Heritage I-III. All the 36 rare hereditary diseases belonging to this entity are described for clinical and molecular genetic purposes, based on the Finnish experience gathered over a period of half a century. In addition, five other diseases are mentioned. They may be included in the list of the "Finnish diseases" after adequate complementary studies.     

The levonorgestrel intrauterine system: therapeutic aspects

Use of the levonorgestrel-releasing intrauterine system (LNG IUS) is associated with a strong reduction in the number of days of bleeding and menstrual blood loss. This effect is based on the marked local action of the intrauterine release of levonorgestrel (LNG) on the endometrium. In suppressed endometrium the production of many highly active compounds ceases. On the other hand, LNG stimulates the synthesis of some regulatory proteins in the endometrium. Reduction of menstrual blood loss results in improvement of the body iron balance and in an increase in hemoglobin concentration. The LNG IUS has been used in the prevention and treatment of iron deficiency anemia. Many studies have demonstrated that the LNG IUS is effective in the treatment of menorrhagia. Reduction of excessive blood loss is seen as soon as the first menstruation after insertion, and at 1 year the reduction is more than 90%. The therapeutic effect is maintained for more than 5 years after first placement of the LNG IUS in the uterine cavity. Correct insertion is essential, and complications and side effects are rare; fertility is preserved, and invasive procedures such as endometrial ablation or hysterectomy and hospitalization are avoided. The third major indication for therapeutic use is in protection of the endometrium in estrogen replacement therapy during peri- and postmenopausal years. A fundal position of the system in the uterine cavity results in reduction of bleeding, and an increasing number of women have no bleeding at all during use of the IUS. Acceptance and continuation of use of the LNG IUS in hormone replacement therapy (HRT) have been high.