Siberian hamster reproduction is mediated by photoperiod-induced changes in gonadal activity. However, little is known about how photoperiod induces cellular changes in ovarian function. We hypothesized that exposing female hamsters to short (inhibitory) as opposed to long (control) photoperiods would induce an apoptosis-mediated disruption of ovarian function. Ovaries and plasma from hamsters exposed to either long (LD, 16 h light:8 h darkness) or short (SD, 8 h light:16 h darkness) days were collected during diestrus II after 3, 6, 9 and 12 weeks and processed for histology or RIA respectively. Apoptosis was assessed by in situ TUNEL and active caspase-3 protein immunolabeling. No significant differences were observed among LD hamsters for any parameter; therefore, these control data were pooled. SD exposure induced a decline in preantral follicles (P < 0.05), early antral/antral follicles (P < 0.01) and corpora lutea (P < 0.01) by week 12 as compared with LD. Terminal atretic follicles appeared by SD week 9; by week 12, these had become the predominant ovarian structures. Estradiol concentrations decreased by weeks 9 and 12 SD when compared with both LD and week-3 SD hamsters (P < 0.05); however, no changes were observed for progesterone. TUNEL-positive follicles in SD ovaries increased at week 3 and subsequently declined by week 12 as compared with LD ovaries (P < 0.01). Active capsase-3 protein immunostaining peaked at SD week 3 as compared with all other groups (P < 0.01). TUNEL and capsase-3 immunolabeling were localized to granulosa cells of late-preantral and early-antral/antral follicles. These data indicate that SD exposure rapidly induces follicular apoptosis in Siberian hamsters, which ultimately disrupts both estradiol secretion and folliculogenesis, resulting in the seasonal loss of ovarian function. IntroductionTo maximize survival when environmental resources are reduced, individuals of many temperate species limit reproductive function seasonally. In mammals, this adaptation is cued primarily by photoperiod-induced alterations in melatonin secretion from the pineal gland. For long-day (LD) seasonal breeders, such as Siberian hamsters (Phodopus sungorus), exposure to long photoperiods (. 12.5 h of light per day; short duration of melatonin release) induces and maintains reproductive function, whereas exposure to short photoperiods (, 12.5 h of light per day; long duration of melatonin release) results in the cessation of reproductive function (Hoffmann 1986, Bronson 1989, Knopper & Boily 2000, Prendergast & Nelson 2001. Extended periods of melatonin secretion negatively affect reproductive activity via inhibition of the hypothalamic-pituitary-gonadal (HPG) axis. In both males and females, short-day (SD) exposure reduces hypothalamic synthesis and secretion of gonadotropin-releasing hormone (GnRH) and, subsequently, the pituitary gonadotropins, follicle-stimulating hormone (FSH) and luteinizing hormone (LH) (Glass 1986, Buchanan & Yellon 1991. Eventually, these endocrine alterations resu...

The matrix metalloproteinases (MMPs) are a family of extracellular matrix-cleaving enzymes involved in ovarian remodeling. In many non-tropical species, including Siberian hamsters, ovarian remodeling is necessary for the functional changes associated with seasonal reproduction. We evaluated MMPs and their endogenous inhibitors (TIMPs), during photoperiod-induced ovarian recrudescence in Siberian hamsters. Hamsters were transferred from long-day (LD;16:8) to shortday (SD;8:16) photoperiods for 14wks, and then returned to LD for 0,1,2,4, or 8wks for collection of ovaries and plasma. Post-transfer (PT) LD exposure increased body and ovarian mass. Numbers of corpora lutea and antral, but not preantral follicles increased in PT groups. Plasma estradiol concentrations were lower in PT wks0−4, and returned to LD levels at PTwk8. No change was observed in relative MMP/TIMP mRNA levels at PTwk0 (SDwk14) as compared to LD. Photostimulation increased MMP-2 mRNA at PTwk8 as compared to PT wks 0−1. MMP-14 mRNA expression peaked at PTwks1−2 as compared to LD levels, while MMP-13 expression was low during this time. TIMP-1 mRNA peaked at PT wk8 as compared to PTwks0−4. No changes were noted in MMP-9 and TIMP-2 mRNA expression. In general, MMP/TIMP protein immunodetection followed the same patterns with most staining occurring in granulosa cells of follicles and corpora lutea. Our data suggest that mRNA and protein for several members of the MMP/TIMP families are expressed in Siberian hamster ovaries during recrudescence. Because of the variation observed in expression patterns, MMPs and TIMPs may be differentially involved with photo-stimulated return to ovarian function.

The BP Deepwater Horizon oil spill (DHOS) created widespread concern about threats to health among residents of the Louisiana Gulf Coast. This study uses data from the Resilient Children, Youth, and Communities study-a longitudinal cohort survey of households with children in DHOS-affected areas of South Louisiana-to consider the effect of DHOS exposure on health trajectories of children, an especially vulnerable population subgroup. Results from latent linear growth curve models show that family DHOS exposure via physical contact and job/income loss both negatively influenced initial child health. However, the effects of physical exposure dissipated over time while the effects of job/income loss persisted. This pattern holds for both general child health and the number of recent physical health problems children had experienced. These findings help to bridge the literature on disaster impacts and resilience/vulnerability, with the literature on socioeconomic status as a fundamental cause of health outcomes over the life course. Keywords BP Deepwater Horizon . Child health . Disaster . Oil spill The Deepwater Horizon oil spill (DHOS) ranks as the largest accidental marine oil spill in history by volume 1 and length of shoreline oiled (Nixon et al. 2016). The disaster was set in motion on April 20, 2010, when the BP-leased Deepwater Horizon oil rig

This paper examines the physical and mental health of children following the Deepwater Horizon oil spill (DHOS). A multi-stage sampling design was used to select households for inclusion in the study. Data were obtained from parental interviews (n = 720) in the harder-hit areas of Louisiana in the US Gulf Coast. Three out of five parents reported that their child had experienced physical health symptoms and nearly one third reported that their child had mental health issues since the oil spill. Both direct physical exposure and indirect economic exposure were found to be predictors of physical and mental health issues among the children. Our findings contribute to bridge the research gap on the impacts of the direct and indirect exposures of the DHOS on the health of children. The study underscores the importance of understanding the health and recovery trajectories of children and youth exposed to disasters. Knowledge gained from this study together with the emerging literature on the effect of the oil spill disaster on children can contribute towards more evidence-based public health policies and enhance the recovery of children and their families in the aftermath of disasters.

The study outlines the critical importance of health and socioeconomic factors in long-term disaster recovery and highlights the need for increased consideration of those factors in post-disaster interventions and recovery monitoring. More research is needed to assess the effectiveness of state and federal assistance programs, particularly among disadvantaged populations. (Disaster Med Public Health Preparedness. 2018;12:172-175).

Hospital administrators should consider the implications of barriers and areas of residence on the disaster response capacity of their workforce. Our findings underscore communication and development of preparedness plans to improve the resilience of hospital workers to mitigate absenteeism.

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