Effects of Photoperiod Manipulation on Gonadal Activity of the Damselfish, Chromis notata.
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ABSTRACT:
SUBMITTER: Lee CH
PROVIDER: S-EPMC5532314 | biostudies-other | 2017 Jun
REPOSITORIES: biostudies-other
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Project description:The objective of this study was to determine whether the previously observed effects of photoperiod on body weight in Siberian hamsters were due to changes in the daily patterns of locomotor activity, energy expenditure, and/or feeding behavior. Adult males were monitored through a seasonal cycle using an automated comprehensive laboratory animal monitoring system (CLAMS). Exposure to a short-day photoperiod (SD; 8:16-h light-dark cycle) induced a significant decline in body weight, and oxygen consumption (Vo(2)), carbon dioxide production (Vco(2)), and heat production all decreased reaching a nadir by 16 wk of SD. Clear daily rhythms in locomotor activity, Vo(2), and Vco(2) were observed at the start of the study, but these all progressively diminished after prolonged exposure to SD. Rhythms in feeding behavior were also detected initially, reflecting an increase in meal frequency but not duration during the dark phase. This rhythm was lost by 8 wk of SD exposure such that food intake was relatively constant across dark and light phases. After 18 wk in SD, hamsters were transferred to a long-day photoperiod (LD; 16:8-h light-dark cycle), which induced significant weight gain. This was associated with an increase in energy intake within 2 wk, while Vo(2), Vco(2), and heat production all increased back to basal levels. Rhythmicity was reestablished within 4 wk of reexposure to long days. These results demonstrate that photoperiod impacts on body weight via complex changes in locomotor activity, energy expenditure, and feeding behavior, with a striking loss of daily rhythms during SD exposure.
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Project description:BackgroundA tumor comprising of different types of tissues (such as hair, muscle, bone, etc.) is known as a teratoma. It is a type of germ cell (cells that make sperm or eggs) tumor. When these germ cells have rapid cancerous growth, then such a teratoma is called a malignant teratoma. We have studied the differences between gonadal and extra-gonadal malignant teratomas and the effects of chemotherapy in both genders.MethodsThe samples of 3799 male and 1832 female patients with malignant teratoma samples, between the ages of 1 and 85+ years, were selected from the years 1973 to 2014. Trends in incidence, estimated prevalence, incidence rates, and frequency were calculated in gonadal and extra-gonadal tumors with age adjustment. The five-year observed, expected, and relative survival rates were analyzed to study the prognosis.ResultsThe gonadal took over a majority percentage of malignant teratomas compared with the extra-gonadal (90% vs. 10% in male; 83% vs. 17% in female). For the male, the total of the gonadal and the extra-gonadal were all significantly decreased from 1973 to 2014 (p < 0.05). For the female, there were no significant trends. As for prevalence, incidence, and frequency, there were two separate peaks of malignant teratomas. One peak was at under 1 year old, which was composed of the extra-gonadal tumor; the other peak was at 20-24 for male and 10-34 for female, which was composed of the gonadal tumor. This separation of the gonadal and extra-gonadal showed a significant difference (p < 0.05). As for the prognosis, the extra-gonadal tumor showed significantly lower survival rates than the gonadal (p < 0.05). In the short term, the survival rate of the chemotherapy group was higher than the supportive care group. However, in the long term, the survival rate of the chemotherapy group was lower than the supportive care group.ConclusionThe gonadal and extra-gonadal malignant teratomas show lots of differences. Chemotherapy might not help improve survival rates.
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