108 research outputs found
Perinatal Drug Abuse And Neonatal Drug Withdrawal
Drug abuse and addiction have significantly increased over the last few decades; specifically, opioid abuse and dependence have increased to epidemic proportions. This increased use of drugs includes women of childbearing age and those who are pregnant. Drug abuse during pregnancy is a serious health risk for both mother and newborn infant. Infants exposed to maternal drugs in fetal life develop signs of drug withdrawal during early neonatal life. This group of withdrawal signs is known as neonatal abstinence syndrome (NAS). Although NAS is not a fatal condition, it results in significant illness and prolonged hospitalization
Effects of Microgravity or Simulated Launch on Testicular Function in Rats
Testes from flight rats on COSMOS 2044 and simulated-launch, vivarium, or caudal-elevation control rats (5/group) were analyzed by subjective and quantitative methods. On the basis of observations of fixed tissue, it was evident that some rats had testicular abnormalities unassociated with treatment and probably existing when they were assigned randomly to the four treatment groups. Considering rats without preexisting abnormalities, diameter of seminiferous tubules and numbers of germ cells per tubule cross section were lower (P less than 0.05) in flight than in simulated-launch or vivarium rats. However, ratios of germ cells to each other or to Sertoli cells and number of homogenization-resistant spermatids did not differ from values for simulated-launch or vivarium controls. Expression of testis-specific gene products was not greatly altered by flight. Furthermore, there was no evidence for production of stress-inducible transcripts of the hsp7O or hsp9O genes. Concentration of receptors for rat luteinizing hormone in testicular tissue and surface density of smooth endoplasmic reticulum in Leydig cells were similar in flight and simulated-launch rats. However, concentrations of testosterone in testicular tissue or peripheral blood plasma were reduced (P less than 0.05) in flight rats to less than 20% of values for simulated-launch or vivarium controls. Thus spermatogenesis was essentially normal in flight rats, but production of testosterone was severely depressed. Exposure to microgravity for more than 2 wk might result in additional changes. Sequelae of reduced androgen production associated with microgravity on turnover of muscle and bone should be considered
Interbular space characterization in adult capybara (Hydrochoerus hydrochaeris) testis
Activation of Cell Cycle Arrest and Apoptosis by the Proto-Oncogene Pim-2
Potent survival effects have been ascribed to the serine/threonine kinase proto-oncogene PIM-2. Elevated levels of PIM-2 are associated with various malignancies. In human cells, a single Pim-2 transcript gives rise mainly to two protein isoforms (34, 41 kDa) that share an identical catalytic site but differ at their N-terminus, due to in-frame alternative translation initiation sites. In this study we observed that the 34 kDa PIM-2 isoform has differential nuclear and cytoplasmic forms in all tested cell lines, suggesting a possible role for the balance between these forms for PIM-2's function. To further study the cellular role of the 34 kDa isoform of PIM-2, an N-terminally HA-tagged form of this isoform was transiently expressed in HeLa cells. Surprisingly, this resulted in increased level of G1 arrested cells, as well as of apoptotic cells. These effects could not be obtained by a Flag-tagged form of the 41 kDa isoform. The G1 arrest and apoptotic effects were associated with an increase in T14/Y15 phosphorylation of CDK2 and proteasom-dependent down-regulation of CDC25A, as well as with up-regulation of p57, E2F-1, and p73. No such effects were obtained upon over-expression of a kinase-dead form of the HA-tagged 34 kDa PIM-2. By either using a dominant negative form of p73, or by over-expressing the 34 kDa PIM-2 in p73-silenced cells, we demonstrated that these effects were p73-dependent. These results demonstrate that while PIM-2 can function as a potent survival factor, it can, under certain circumstances, exhibit pro-apoptotic effects as well
Age-related changes in the expression of 11beta-hydroxysteroid dehydrogenase type 2 in rat Leydig cells.
Reactive oxygen species and male reproductive hormones
Reports of the increasing incidence of male infertility paired with decreasing semen quality have triggered studies
on the effects of lifestyle and environmental factors on the male reproductive potential. There are numerous exogenous
and endogenous factors that are able to induce excessive production of reactive oxygen species (ROS) beyond that of
cellular antioxidant capacity, thus causing oxidative stress. In turn, oxidative stress negatively affects male reproductive
functions and may induce infertility either directly or indirectly by affecting the hypothalamus-pituitary-gonadal (HPG)
axis and/or disrupting its crosstalk with other hormonal axes. This review discusses the important exogenous and
endogenous factors leading to the generation of ROS in different parts of the male reproductive tract. It also highlights
the negative impact of oxidative stress on the regulation and cross-talk between the reproductive hormones. It further
describes the mechanism of ROS-induced derangement of male reproductive hormonal profiles that could ultimately
lead to male infertility. An understanding of the disruptive effects of ROS on male reproductive hormones would
encourage further investigations directed towards the prevention of ROS-mediated hormonal imbalances, which in turn
could help in the management of male infertility
Testosterone modulates cardiac contraction and calcium homeostasis: cellular and molecular mechanisms
- âŠ