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Biomedical subjects

A Iritani

Publications and source records attributed to A Iritani.

At least 73 records · Page 4Linked to original sources
PubMed1980

Penetration of zona-free hamster eggs in vitro by goat spermatozoa preincubated in the reproductive tract isolated from a maturing gilt.

When goat spermatozoa were preincubated for 5-5.5 hr in the isolated uterus and oviduct from a maturing gilt, they developed the ability to penetrate zona-free hamster eggs in vitro. Overall penetration rates were 17% and 0%, respectively, 1 hr after insemination, and these increased to 59% and 54% 2 hr later. The penetration rates were not improved by incubation longer than 2 hr after insemination up to 5 hr. Goat spermatozoa preincubated for 5 hr in a m-KRB solution with or without goat serum penetrated zona-free hamster eggs with difficulty. The results suggest that a functional change in the ability of goat spermatozoa to penetrate zona-free hamster eggs may occur in the reproductive tract of different species.

Animals↗
PubMed1980

Effect of inhibin-like substance isolated from porcine follicular fluid on the follicle-stimulating hormone (FSH) level in mouse serum and on FSH binding to porcine granulosa cells.

An inhibin-like substance, a follicle-stimulating hormone (FSH) inhibitor, was isolated from porcine follicular fluid and purified. Serum FSH levels of unilaterally ovariectomized mice which received injections of the inhibitor were lower than those of unilaterally ovariectomized mice which received injections of saline. The inhibitor also suppressed FSH binding to granulosa cells in vitro. These results suggest that this protein is an FSH inhibitor and that it has two modes of action: suppression of FSH levels in serum and suppression of FSH binding to granulosa cells.

Animals↗
PubMed1980

Fertilization in vitro of hamster and mouse eggs in a chemically defined medium.

Hamster and mouse eggs with follicular cells were penetrated by epididymal spermatozoa in a modified Krebs-Ringer-bicarbonate solution known to be suitable for fertilization of rat eggs in vitro. The highest proportion (84-88%) of hamster eggs penetrated was observed when 6-30 eggs with follicular cells were introduced into 10 microliter sperm suspension. Greater volumes of sperm suspension reduced the proportions of eggs fertilized, while increased numbers of eggs in the same volume gave greater penetration rates. No fertilization was observed when 21-30 denuded hamster eggs were introduced into 10-100 microliter sperm suspension, indicating that capacitation and/or acrosome reaction of hamster epididymal spermatozoa was induced only by the post-ovulatory oviduct contents in this medium. However, when small numbers (10-20) of mouse eggs with or without follicular cells were incubated in a large volume (400 microliter) of sperm suspension 84-96% and 91% were penetrated, respectively, suggesting a lack of importance of the products of ovulation on mouse sperm capacitation. The incidence of polyspermy was very low for the hamster (0-13%) and mouse eggs (0-10%).

Animals↗
PubMed1980

Survival of mouse embryos frozen and thawed rapidly.

Mouse morulae were frozen rapidly to -196 degrees C in the presence of 1.0-2.5 M-DMSO by a 3-step procedure; the samples were seeded at -4 to -8 degrees C, held at -20 degrees C in an ethanol bath for 10 min, suspended over liquid nitrogen at approximately -100 degrees C for 10 min and then plunged directly into liquid nitrogen at -196 degrees C. The cooling rate between -20 and -75 degrees C was approximately 17 degrees C/min. In all concentrations of DMSO significantly higher proportions of embryos developed to fully expanded blastocysts after 48 h in culture after rapid thawing (360 degrees C/min) than after slow thawing (25 degrees C/min). The highest survival rates were obtained for the embryos frozen rapidly in the presence of 1.5 and 2.0 M-DMSO (36 and 53% respectively). Various methods for removal of DMSO (2.0 M) were tested with the 3-step freezing and rapid thawing procedures. The best results for development to fully expanded blastocysts were obtained with PBS + 2.0 M DMSO + 0.5 M-sucrose (2 min) followed by PBS + 0.5 M-sucrose (2 min) at room temperature (82%) and with stepwise dilution in PBS at 30 degrees C (70%). When 26 embryos developed to blastocysts in culture after rapid freezing and thawing were transferred into 2 recipients, 11 newborn young (42%) were obtained.

Animals↗
PubMed1979

Time requirement for capacitation of boar spermatozoa assessed by their ability to penetrate the zona-free hamster egg.

Boar spermatozoa were preincubated for various times in the isolated uterus and oviduct from a maturing gilt and used to inseminate zona-free hamster eggs. The proportions of eggs penetrated and activated were increased, and the interval between insemination and sperm penetration was shortened when the spermatozoa were preincubated for 4--5.5 h instead of 2--.5 h. Overall penetration rates were higher and sperm penetration occurred about 1 h earlier when the eggs were inseminated with spermatozoa preincubated in the uterus than in the oviduct. It is concluded that the change in ability of boar spermatozoa to penetrate zona-free hamster eggs is due to capcitation which requires 4--4.5 h and 5--5.5 h of preincubation in the isolated uterus and oviduct, respectively.

Animals↗
PubMed1979

Biological activity of secretory IgA--comparison of agglutinating specificity with SIgA and Ca++-dependent agglutinin--.

Ca++-dependent bacterial agglutinin was isolated from the human parotid saliva by gel filtration of Sepharose 2B. The agglutinin appeared in the void volume fractions. Treatment of this agglutinin with EDTA resulted in the loss of its ability to agglutinate the bacteria. Standardized solutions of the agglutinin were tested for the agglutinating activity against 18 strains of oral indigenous bacteria. It was found that the agglutinin exhibited varying degrees of activity to all the test strains and the activity was generally higher than that of secretory IgA. It was also found that the receptor sites of the Ca++-dependent agglutinin for Str. sanguis and Str. mitis were identical whereas SIgA contained a number of available binding sites, for different bacterial species.

Adult↗
PubMed1978

Effect of various hexoses on sperm capacitation and penetration of rat eggs in vitro.

Fertilization of rat eggs in vitro could not be achieved when epididymal spermatozoa were preincubated and eggs in clots incubated in a chemically defined medium without D-glucose. Very high proportions (84-100%) of eggs examined were undergoing fertilization when 2.78-8.34 mM-D-glucose were included in the medium. The substitution of D-fructose or D-galactose for D-glucose resulted in very poor penetration rates (0-4%), but D-mannose was effective for fertilization (59-99% penetration). Incubations for sperm capacitation and egg fertilization in different media containing the various hexoses showed that rat epididymal spermatozoa could be partly capacitated without hexose, that D-glucose, D-mannose or D-galactose but not D-fructose is effective for sperm capacitation and that only D-glucose and D-mannose supported penetration of eggs in vitro.

Animals↗
PubMed1978

Identification, purification and immunohistochemical detection of the inhibitor from porcine ovarian follicular fluid to compensatory ovarian hypertrophy in mice.

An inhibitor to compensatory ovarian hypertrophy in mice was detected in porcine follicular fluid. Compensatory hypertrophy was inhibited by treatment with 0.6 ml whole follicular fluid, 0.2 ml of the non-dialysable fraction, or a fraction of the fluid salted out by ammonium sulphate at a saturation of 14.5--18.5%. The salted-out fraction was separable into two peaks by Sephadex G-200 column chromatography and the second peak, detectable as a single band by polyacrylamide gel disc electrophoresis, contained all the inhibitory activity. Specific fluorescence of an antiserum to the second peak was demonstrated at the granulosa cells.

Animals↗
PubMed1978

Sperm penetration in vitro of pig follicular oocytes matured in culture.

Boar ejaculated and epididymal spermatozoa were preincubated in modified KRB or the isolated oviduct and uterine horn of an oestrous sow for 4.5-5 h at 37 degrees C before introduction into medium containing ovarian oocytes previously cultured for 24 h. At examination 17-20 h after insemination 60.6% of the total oocytes had reached at least the 2nd metaphase. The proportions of oocytes penetrated (i.e. enlarged sperm head or male pronucleus and corresponding sperm tail) were 0, 10.0 and 16.7% with ejaculated spermatozoa, and 3.3, 19.6 and 26.4% with epididymal spermatozoa preincubated in modified KRB, oviduct and uterus, respectively. Although the proportion of oocytes with morphologically normal male and female pronuclei was low (10/36 = 27.8%), the results suggest that boar spermatozoa can be capacitated in the isolated genital tract of an oestrous sow and that capacitation of epididymal is better than that of ejaculated spermatozoa.

Animals↗