GH mediates exercise-dependent activation of SVZ neural precursor cells in aged mice

Here we demonstrate, both in vivo and in vitro, that growth hormone (GH) mediates precursor cell activation in the subventricular zone (SVZ) of the aged (12-month-old) brain following exercise, and that GH signaling stimulates precursor activation to a similar extent to exercise. Our results reveal that both addition of GH in culture and direct intracerebroventricular infusion of GH stimulate neural precursor cells in the aged brain. In contrast, no increase in neurosphere numbers was observed in GH receptor null animals following exercise. Continuous infusion of a GH antagonist into the lateral ventricle of wild-type animals completely abolished the exercise-induced increase in neural precursor cell number. Given that the aged brain does not recover well after injury, we investigated the direct effect of exercise and GH on neural precursor cell activation following irradiation. This revealed that physical exercise as well as infusion of GH promoted repopulation of neural precursor cells in irradiated aged animals. Conversely, infusion of a GH antagonist during exercise prevented recovery of precursor cells in the SVZ following irradiation

Growth hormone responsive neural precursor cells reside within the adult mammalian brain

The detection of growth hormone (GH) and its receptor in germinal regions of the mammalian brain prompted our investigation of GH and its role in the regulation of endogenous neural precursor cell activity. Here we report that the addition of exogenous GH significantly increased the expansion rate in long-term neurosphere cultures derived from wild-type mice, while neurospheres derived from GH null mice exhibited a reduced expansion rate. We also detected a doubling in the frequency of large (i.e. stem cell-derived) colonies for up to 120 days following a 7-day intracerebroventricular infusion of GH suggesting the activation of endogenous stem cells. Moreover, gamma irradiation induced the ablation of normally quiescent stem cells in GH-infused mice, resulting in a decline in olfactory bulb neurogenesis. These results suggest that GH activates populations of resident stem and progenitor cells, and therefore may represent a novel therapeutic target for age-related neurodegeneration and associated cognitive decline

Knowledge, attitudes, and practices of cervical Cancer screening among HIV-positive and HIV-negative women participating in human papillomavirus screening in rural Zimbabwe

BackgroundWomen in low- and middle-income countries are at the highest risk of cervical cancer yet have limited access to and participation in cervical cancer screening programs. Integrating self-collected, community-based screening offers a potential primary screening method in areas of limited resources. In this paper, we present a study evaluating knowledge, attitudes, and practices of cervical cancer and Human Papilloma Virus (HPV) in rural Zimbabwe.MethodsWe performed a community-based cross-sectional knowledge, attitudes and practices of HPV and cervical cancer study in rural Zimbabwe from January 2017-May 2017. Women were selected for the study via random number generation from complete lists of inhabitants in the study area if they satisfied the inclusion criteria (≥30-years-old, ≤65-years-old, not pregnant, intact uterus). If selected, they participated in a 19-question structured knowledge, attitudes and practices survey. The questionnaire included questions on demographics, education, knowledge of HPV, cervical cancer, and risk factors. Chi-squared tests were evaluated comparing knowledge, attitudes and practices relating to HPV and cervical cancer screening with actual infection with HPV. Women were also offered a voluntary HIV and self-collected HPV screening.ResultsSix hundred seventy-nine women were included in the knowledge, attitudes and practices survey. Most women (81%) had heard of cervical cancer while the majority had not heard of HPV (12%). The number of women that had been screened previously for cervical cancer was low (5%). There were no significant differences between and within groups regarding knowledge of cervical cancer and actual overall infection with HR-HPV, HPV 16, and HPV 18/45 test results.ConclusionsMost women in rural Zimbabwe have heard of cervical cancer, but the number that had been screened was low. Extending existing outreach services to include cervical cancer screening, potentially including HPV screening, should include cervical cancer/HPV education and screening triage. This approach would serve to bridge the gap between knowledge and screening availability to address some of the barriers to cervical cancer care still affecting women in many regions of the world