Search results for "sperma"
showing 6 items of 296 documents
Protandric hermaphrodite peculiarities in Amphiprion frenatus Brevoort (Teleostei, Pomacentridae)
1990
Electron microscopy of the male phase of the ovotestis of Amphiprion frenatus, a protandric hermaphrodite, showed no connective tissue between male and female areas and, as the basal lamina was lacking both along the seminiferous tubules and round the previtellogenic oocytes, the male and female germ cells were only separated by their respective surrounding somatic cells (Sertoli and follicle cells). Besides previtellogenic oocytes, oocytes in meiotic prophase and very small (young) previtellogenic oocytes, were detected in the ovarian part, as spermatogenesis proceeded, revealing oogenetic activity. Degeneration of some previtellogenic oocytes and their follicle cells was discernible.
Angiographien im Kleinkindes- und Kindesalter
1993
Between 1973 and 1991 we performed 160 percutaneous angiograms (130 arteriograms, 30 phlebograms) in children and infants; 12 patients were less than one year and 52 less than ten years old. 44 of the examinations were done by a DSA technique. The examinations were carried out under general anaesthesia except in 8 cases. In 50.7% an arteriogram was carried out for the investigation of a suspected or known tumour, in 9.3% an arteriogram was required following trauma. The most common phlebographic examination was for the demonstration of the spermatic vein; in 27 patients this was done for cryptorchidism or a varicocele. The only complication following a diagnostic angiogram was perforation o…
66 RELATIONSHIP BETWEEN PLASMA CHLORIDE LEVELS AND FOLLICLE DIAMETER IN CYCLING SPANISH PUREBRED MARES
2014
Several studies in cows have shown that plasma levels of chloride are positively correlated with the diameter of the preovulatory follicle (FD), establishing at the same time a significant positive association between plasma levels and intraoviducal concentration of this electrolyte (Hugentobler et al. 2007). These relationships may reflect the influence of changes in systemic metabolic plasma on follicular fluid, physiological events that might be closely related to the quality of the oocyte and granulosa cells of the preovulatory follicle (LeRoy et al. 2004). However, these mechanisms remain unknown in the mare. The objective of this research was to investigate the relationship between p…
Genetic and potential non-genetic benefits increase offspring fitness of polyandrous females in non- resource based mating system
2010
Background: The adaptive significance of female polyandry is currently under considerable debate. In non-resource based mating systems, indirect, i.e. genetic benefits have been proposed to be responsible for the fitness gain from polyandry. We studied the benefits of polyandry in the Arctic charr (Salvelinus alpinus) using an experimental design in which the material investments by the sires and maternal environmental effects were controlled. Results: Embryonic mortality showed a strong paternal genetic component, and it was lower in polyandrously fertilized offspring (sperm competition of two males) than in monandrous fertilizations. We also found that high sperm velocity was associated w…
First insights into female sperm storage duration in tardigrades.
2022
Female sperm storage is ubiquitous in the animal kingdom and it has been shown to be linked to several evolutionary processes, from postcopulatory sexual selection to dispersal. Here we report, for the first time, long-term sperm storage in females of the tardigrade Macrobiotus polonicus. Females, isolated after a short contact with a male, were able to use the stored sperm for up to 5 weeks (mean of 2 weeks), which translates to a considerable proportion of female post-mating longevity under controlled laboratory conditions (60% on average). Our study provides the first insights into the duration of sperm storage, an underexplored feature of the reproductive biology of tardigrades. Additio…
Chromatin Maturity Index (CMI) in unfixed and live spermatozoa and Aniline Blue (AB) stained as an additional evaluation parameter in idiopathic male…
2021
Study question: To investigate whether idiopathic male infertility may be due to the presence of histones in motile spermatozoa using a modified AB staining protocol. Summary answer: No correlation between CMI in live motile spermatozoa, DNA Fragmentation Index (DFI) and other conventional seminal parameters were found in male infertile patients. What is known already: The AB stain discriminates between lysine-rich histones and arginine/cysteine-rich protamines. Transition from histones to protamines during spermatogenesis remodels chromatin packaging and abnormalities in the substitution of those proteins maybe interfere with seminal parameters and affect male infertility. The correlation …