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Query: UMLS:C0851184 (
thinning
)
11,252
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Ultrastructural study confirmed that, in rats, vitamin A deficiency initially caused the sloughing of some spermatids and spermatocytes into the lumina of the seminiferous tubules around day 3 following the initial decrease of body weight. From days 5 to 10, a considerable number of spermatocytes and spermatids, which still remained in the epithelium, underwent necrosis. Several stages of dying spermatocytes and abnormal spermatids were observed. The latter were distinguished by the presence of chromatin aggregating along the nuclear envelopes and highly vacuolated mitochondria. These cells range from single to multinucleate forms. They were incapable of differentiating further into
spermatozoa
and ultimately degenerated. Within the same period, Sertoli cells exhibited numerous darkly stained lysosome-like inclusions, and the upper part of their cytoplasm appeared as irregular processes, some of which were broken off and resulted in the
thinning
of the epithelium. From days 10 to 20, the remaining germ cells comprised mainly spermatogonia and few abnormal spermatocytes. The latter appeared enlarged and were very lightly stained. Their nuclei exhibited unusual blocks of heavily condensed chromatin amidst very highly dispersed chromatin fibers. Though their number was reduced, most of the spermatogonia appeared unaltered. Processes of Sertoli cells became even more irregular and were interrupted at certain sites by large empty spaces. Darkly stained inclusions in their cytoplasm were fewer than observed earlier.
...
PMID:Cytological changes in the testes of vitamin-A-deficient rats. II. Ultrastructural study of the seminiferous tubules. 41 27
Sulphatase preparations from Abalone entrails, the limpet Patella vulgata and ox liver, as well as artificial substrates for these enzymes, were used in the hamster in vitro fertilization system to study the possible roles of sperm sulphatases in sperm-zona pellucida interactions. p-nitrophenyl sulphate, p-nitrocatechol sulphate, ascorbate 2-sulphate, as well as D-glucopyranose and D-galactopyranose, both sulphated at the 3, 4 or 6 position but not the 2 position, inhibited fertilization in a dose-dependent manner. Sperm-egg fusion was not inhibited by the substrates used and eggs pre-treated with sulphates could readily be fertilized. Sperm motility and therefore viability was unaffected by inhibitory concentrations of substrates as determined by rhodamine 123 labelling of motile
spermatozoa
. Acrosomal integrity of rhodamine-labelled
spermatozoa
was assessed and found to be unaffected by inhibitory levels of substrates. Fertilization was inhibited by high concentrations of the two molluscan sulphatases but not by purified ox liver sulphatase. Pre-treatment of eggs with these enzymes did not prevent fertilization. Long-term exposure of hamster oocytes to N-acetylhexosaminidase or limpet sulphatase caused
thinning
and distension of the zona pellucida but these changes were not observed with the ox liver sulphatase. The results suggest that a glycosulphatase is probably released from hamster
spermatozoa
during sperm-egg adhesion and, or, penetration. If sperm-egg adhesion molecules are sulphated, the commercially available sulphatases would be unsuitable for their characterization.
...
PMID:Involvement of sperm sulphatases in early sperm-zona interactions in the hamster. 293 56
Histochemical studies of the rat epididymis after treatment with alp ha-chlorohydrin (U-5897) are presented. 14 sexually mature male rats received either daily subcutaneous injections of 50 mg U-5907/kg body weight or distilled water for 20 days. The animals were sacrificed the day following the last injection. U-5897 induced temporary sterility as demonstrated by blocked transport of
spermatozoa
, and spermatogenic cells eliminated from the spermatogenic epithelium which became blocked in the caudal part of the epididymis. This resulted in the distension of the segment of the distal part of the epididymal duct and to the
thinning
of the epithelium which lined the altered segment. Alkaline and acid phosphatases, nonspecific esterases, succinate and glucose-6-phosphate dehydrogenases and reduced nicotinamide-adenine dinucleotide tetrazolium reductase in the unchanged part of the epididymal duct were comparable to control rats whereas the altered part of the epididymis showed these activities to much weaker degrees or to be absent altogether.
...
PMID:Histochemical studies of the rat epididymis after treatment with alpha-chlorohydrin (U-5897). 415 41
We investigated whether the aged oocytes maintain the ability to fuse with
spermatozoa
when the oocyte investment is removed. In the first study, 87 two-days-old oocytes provided from IVF-ET programme were treated with pronase to dissolve the zona pellucida. The oocytes were then inseminated with 100, 10 or 1 per microliters sperm and the incidence of monospermic and polyspermic fertilization was determined. In the second study 100 one-day-old unfertilized oocytes obtained from 18 IVF patients with "zero fertilization" at initial insemination were treated in the same way to either remove or
thinning
of the zona pelucida. They were then re-inseminated with 10 motile sperm per microliter of the husband. The incidence of monospermic and polyspermic fertilization were 0.0% (0/13) and 61.6% (8/14), respectively, with a sperm count of 100/microliters, 7.3% (3/41) and 31.6% (13/41) with 10/microliters, and 14.2% and 11.9% (5/33) with 1/microliter. The incidence of monospermic and polyspermic fertilization with reinsemination of one day old oocytes were 12.5% (3/24) and 25.0% (6/24) after zona removal and were 18.3% (9/49) and 10.2% (5/49) after zona
thinning
. The incidence of fertilization by zona removal was significantly higher than the results of conventional reinsemination (p < 0.001). It appeared that human aged oocytes maintain the ability to fuse
spermatozoa
after even two days. A higher rate of monospermic fertilization was obtained by carefully controlling the number of
spermatozoa
for insemination. We concluded that zona manipulation might improve fertilization in vitro in case of severe male factor infertility.
...
PMID:Zona manipulation in an assisted reproductive technologies (ART) programme. 859 Nov 15
Cyclin-dependent kinase 16 (CDK16, PCTK1) is a poorly characterized protein kinase, highly expressed in the testis and the brain. Here, we report that CDK16 is activated by membrane-associated cyclin Y (CCNY). Treatment of transfected human cells with the protein kinase A (PKA) activator forskolin blocked, while kinase inhibition promoted, CCNY-dependent targeting of CDK16-green fluorescent protein (GFP) to the cell membrane. CCNY binding to CDK16 required a region upstream of the kinase domain and was found to be inhibited by phosphorylation of serine 153, a potential PKA phosphorylation site. Thus, in contrast to other CDKs, CDK16 is regulated by phosphorylation-controlled cyclin binding. CDK16 isolated from murine testis was unphosphorylated, interacted with CCNY, and exhibited kinase activity. To investigate the function of CDK16 in vivo, we established a conditional knockout allele. Mice lacking CDK16 developed normally, but male mice were infertile. Spermatozoa isolated from their epididymis displayed
thinning
and elongation of the annulus region, adopted a bent shape, and showed impaired motility. Moreover, CDK16-deficient
spermatozoa
had malformed heads and excess residual cytoplasm, suggesting a role of CDK16 in spermiation. Thus, CDK16 is a membrane-targeted CDK essential for spermatogenesis.
...
PMID:Cyclin-dependent kinase 16/PCTAIRE kinase 1 is activated by cyclin Y and is essential for spermatogenesis. 2218 64
GEMC1 and MCIDAS are geminin family proteins that transcriptionally activate E2F4/5-target genes during multiciliogenesis, including
Foxj
1
and
Ccno
Male mice that lacked
Gemc1
,
Mcidas
or
Ccno
were found to be infertile, but the origin of this defect has remained unclear. Here, we show that all three genes are necessary for the generation of functional multiciliated cells in the efferent ducts that are required for
spermatozoa
to enter the epididymis. In mice that are mutant for
Gemc1
,
Mcidas
or
Ccno
, we observed a similar spectrum of phenotypes, including
thinning
of the seminiferous tubule epithelia, dilation of the rete testes, sperm agglutinations in the efferent ducts and lack of
spermatozoa
in the epididymis (azoospermia). These data suggest that defective efferent duct development is the dominant cause of male infertility in these mouse models, and this likely extends to individuals with the ciliopathy reduced generation of multiple motile cilia with mutations in
MCIDAS
and
CCNO
.
...
PMID:Defects in efferent duct multiciliogenesis underlie male infertility in GEMC1-, MCIDAS- or CCNO-deficient mice. 3093 78
To elucidate the process whereby sperm arrive at an egg in the female reproductive organs, it is essential to investigate how rheological properties of the fluid around mammalian
spermatozoa
affect their motility. We examined the motility and flagellar waveform of bovine sperm swimming in a fluid with similar rheological properties as mammalian cervical mucus. The results indicated that the surrounding rheological properties largely affected the flagellar waveform of mammalian
spermatozoa
; in particular, shear-
thinning
viscoelastic fluid increased the progressive motility of the sperm. To investigate the influence of flagellar waveform on sperm motility in more detail, the waveform was expressed as a function and the progressive thrust of the sperm was calculated based on the empirical resistive force theory. The results of this study showed that the progressive thrust increased with the curvature of the flagellar tip. Moreover, we calculated the thrust efficiency of motile sperm. Results showed that the thrust efficiency in shear-
thinning
viscoelastic fluids was larger than that in Newtonian fluids, regardless of viscosity. This suggests that motile sperm in cervical mucus move efficiently by means of a motion mechanism that is suited to their surrounding environment.
...
PMID:Study of bovine sperm motility in shear-thinning viscoelastic fluids. 3095 48