Search results for "Endocrine System"
showing 10 items of 1530 documents
Verbal performance during stress in healthy older people
2018
The impact of stress on the dehydroepiandrosterone (DHEA) response in older population is understudied. This study investigated, in healthy older people, whether the DHEA and cortisol responses to the Trier Social Stress Test (TSST) was related to performance on this task. Both speech (rated by committee and self-rated) and arithmetic (number of mistakes) performance were assessed. Sixty-five participants (55–77 years old) were exposed to the TSST. Increases in negative affect, state anxiety, and cortisol levels could be observed, but there were no significant changes in positive affect or DHEA levels. Interestingly, a larger DHEA response was related to better verbal performance after cont…
Occurrence of the interference of sperm-associated antibodies on sperm fertilizing ability as evaluated by the sperm-zona pellucida binding test and …
1997
PROBLEM: This study was performed to evaluate the occurrence as well as the level of the interference of sperm-associated antibodies on fertilization process. METHOD: Motile sperm suspensions from 28 infertile patients with high degree of autoimmunization against the sperm head were tested with the zona pellucida (ZP) binding test and with the sperm penetration assay (SPA) enhanced with TEST-yolk buffer. Both tests were also performed using donor sperm exposed and non-exposed to the patients' circulating sperm antibodies. RESULTS: A low ZP-binding was exhibited by sperm from 50% of patients with normal semen profile. All normozoospermic patients with low ZP-binding showed circulating sperm-…
Electron microscopic study on the larval and adult corpus allatum of Oncopeltus fasciatus dallas (insecta, heteroptera)
1973
1. The ultrastructure of the corpora allata of last larval instars and adults of Oncopeltus was studied. The unpaired gland undergoes submicroscopic alterations and shows signs of degradation in old animals. The organ is partly covered and penetrated by corpus cardiacum tissue. Axons with different types of neurosecretory granules form synaptoid contacts with the corpus allatum cells.
Germline deletion of Cetn1 causes infertility in male mice
2013
Centrins are calmodulin-like Ca2+-binding proteins that can be found in all ciliated eukaryotic cells from yeast to mammals. Expressed in male germ cells and photoreceptors, centrin 1 (CETN1) resides in the photoreceptor transition zone and connecting cilium. To identify its function in mammals, we deleted Cetn1 by homologous recombination. Cetn1−/− mice were viable and showed no sign of retina degeneration suggesting that CETN1 is nonessential for photoreceptor ciliogenesis or structural maintenance. Phototransduction components localized normally to the Cetn1−/− photoreceptor outer segments, and loss of CETN1 had no effect on light-induced translocation of transducin to the inner segment.…
Population dependent effects of photoperiod on diapause related physiological traits in an invasive beetle (Leptinotarsa decemlineata).
2012
Organisms undergoing latitudinal range expansion face a change in the photoperiod which can lead to a mismatch between the timing of seasonal changes in physiological and life history traits with seasonal environmental changes. This mismatch can lead to lowered survival, for example, due to unsynchronized diapause timing. Successful range expansion even in recent introductions requires that organisms which use the photoperiod for seasonal predictions should show interpopulational differences in photoperiodic responses at different latitudes, as the photoperiod is a function of latitude. We investigated among population differences in photoperiodic responses of life history and physiological…
Cry characteristics of 172 healthy 1-to 7-day-old infants.
2002
A total of 1,836 cry signals from 172 healthy babies, 1–7 days old, were analysed with sound spectrography. The mean values for the 8–15 cries from each infant were calculated and used for the statistical analyses. The mean duration of the cry signals was 1.4 ± 0.6 s. The mean fundamental frequency was 496 ± 95 cps (Hz). Fifty percent of the mean fundamental frequencies in the 8–15 cries analysed from each baby varied between 450 and 520 Hz. Of the children, 93% had cries with a mean fundamental frequency below 600 Hz. The mean value of the highest point of the fundamental frequency was 583 ± 151 Hz and of the lowest point 398 ± 75 Hz. The melody type had mainly a rising-falling contour, th…
Apoptosis of male germ-line stem cells after laser ablation of their niche.
2007
AbstractMale germ-line stem cells (GSCs) and their niche-the apical cells or hub cells-display a unique feature at the apices of insect testicular follicles. In the locust, Locusta migratoria, the niche consists of only one large apical cell surrounded by about 60 GSCs. The apical cell can be readily identified in the intact follicle. Using laser ablation it is feasible to destroy the apical cell exclusively without injuring neighboring GSCs or any other cells. The most immediate effect on GSCs is the loss of their structural polarity. Beginning about 3 h after laser treatment chromatin starts to clump and condense in individual GSCs, and some show the first signs of cellular breakdown. The…
Regulation of noradrenergic coerulean neuronal firing mediated by 5-HT2 receptors: involvement of the prepositus hypoglossal nucleus.
1991
Abstract Previous studies have indicated a 5-HT2-mediated inhibitory influence on unit activity in the locus coeruleus. In the present work, attempts were made to determine which area(s) of the brain is (are) involved in this effect: (1) Microiontophoretic application of serotoninergic compounds (quipazine, ketanserin, RU 24969 (Roussel Uclaf), 8-hydroxy-2(di-n-propylamino) tetralin (8-OH-DPAT), metergoline, serotonin) in the locus coeruleus, did not alter the coerulean discharge. Local microinjection of quipazine or ketanserin in the area of the locus coeruleus, as well as in one of its major afferents, the prepositus hypoglossi, had no effect on the unit activity in the locus coeruleus. 1…
Determining the relationship between bull sperm kinematic subpopulations and fluorescence groups using an integrated sperm quality analysis technique.
2017
The aim of the present study was to determine whether there is an association between the kinematic sperm subpopulations and fluorescent groups in bulls using a new fluorescent staining method that allows classification of spermatozoa into groups depending on their acrosomal and membrane integrity, as well as functional status, without inhibiting sperm motility. Cryopreserved semen samples from 10 Holstein bulls were used in the study. A multiparametric analysis of results obtained by the ISAS 3Fun kit (Proiser) was performed. The different fluorescent groups were detected and their motility characteristics evaluated using ISAS software. Clustering procedures using the kinematic data resul…
Morphological investigation of the deep pineal of the rat.
1980
The results presented here reveal that in adult Sprague-Dawley and Wistar rats the pineal gland represents a complex rather than a single organ. Regularly one can distinguish (i) pineal tissue in the intercommissural region as a deep pineal, (ii) a superficial pineal, which represents the major part of the pineal complex, and (iii) nearly always a parenchymal stalk of variable length. The volume of the deep pineal with the adjacent parenchymal stalk exhibits great interindividual variation. It amounts to 127 +/- 39 X 10(5) mum3 (mean +/- standard deviation). The histological appearance of the deep and superficial pineal tissue is fairly similar. The intrinsic cells of the deep and superfici…