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Biomedical subjects

M Kinutani

Publications and source records attributed to M Kinutani.

At least 19 recordsLinked to original sources
PubMed1999

Effects of pentoxifylline on sperm motion characteristics in normozoospermic men defined by a computer-aided sperm analysis.

This study was conducted to determine whether pentoxifylline has an in vitro effect on sperm motion characteristics in normozoospermic men. The subjects of the study were 15 male volunteers. After the spermatozoa were washed with mBWW medium, the sperm suspension was divided into two aliquots: one was treated with 1 mg/ml pentoxifylline, the other was used as a control. The sperm motion characteristics were examined by an HT-M2030 at 30, 60, 120, 180, 240 and 300 min during continuous exposure to the drug. As results, pentoxifylline increased the curvilinear velocity and the lateral head displacement. However, it did not affect sperm motility, the straight line velocity. Pentoxifylline may improve sperm fertilizing ability by altering the characteristics of sperm motion, not by increasing the number of motile spermatozoa.

Computers↗
PubMed1996

Further observation of leucocyte migration through the endothelium of venules in the posterior latissimus dorsi muscle of the quail-chick spinal cord chimeras.

The migration of leucocytes through the walls of venules was examined in detail in the posterior latissimus dorsi muscle of quail-chick spinal cord chimeras, in which flaccid paralysis of the wings was observed. Examinations were made from the 70th to 80th day after hatching. Muscle fibers were degenerated and intramuscular nerve bundles destroyed. Massive leucocytes (almost lymphocytes) were found around the venules, depending on the passage of wandering leucocytes through the endothelium. Lymphocytes penetrated and were encased in the cytoplasm of the venular endothelial cell, and did not pass through the interendothelial junction. These findings suggest that, in the venules of the atrophied chimeric muscle, wandering leucocytes in the blood may pass through the endothelial cell body and migrate into the inflamed extravascular space.

Animals↗
PubMed1995

Human spermatozoa attach to trypsin-treated hamster zonae pellucidae but do not undergo acrosome reactions.

The acrosome reaction by spermatozoa is an indispensable prerequisite for fertilization, and zonae pellucidae of human oocytes induce this reaction in the human spermatozoa attached to them. Human spermatozoa can attach to the zona pellucida of hamster oocytes when the oocytes have been treated with trypsin. We examined whether or not trypsin-treated hamster zona pellucida induces the acrosome reaction of human spermatozoa. Ten semen samples from 7 donors of proven fertility were examined in the present study. Highly motile spermatozoa were obtained by a swim-up method, and pre-incubated for 1 or 6 hours in modified Biggers, Whitten and Whittingham's (mBWW) medium supplemented with human serum albumin. The spermatozoa were then co-incubated for 1 hour with trypsin-treated hamster oocytes to allow sperm attachment to the zona. The spermatozoa on the zona were incubated for 3 additional hours in the mBWW medium. The percentage of acrosome reacted spermatozoa (%AR) was determined before and after the 3-hours of incubation. The %AR in the sperm suspension was also determined. There was no significant difference in the %AR between the spermatozoa attached to the zona pellucida and those in suspension during the incubation for 3 hours. These results indicate that the trypsin-treated hamster zona pellucida does not induce the acrosome reaction of human spermatozoa.

Acrosome↗
PubMed1993

Studying brain development with quail-chick neural chimeras.

Avian embryonic neural chimeras are constructed by substituting defined areas of the neural epithelium of a chick embryo by their exact counterpart obtained from a quail embryo at the same developmental stage. The experiment can also be performed using the quail as a host and the chick as a graft donor. The stages elected are either the late neurula (0 to 3 somites) or the stage after cephalic vesicles formation (10 to 14 somites) but in all cases before the onset of vascularization of the neural primordium. Quail and chick territories can be recognized in the chimeras any time after the graft owing to the particular structure of the quail nucleus or by means of species-specific antibodies. Quail-chick chimeras have been instrumental in the study of the ontogeny of the medulla oblongata and of the cerebellum. The complex morphogenetic movements and cell migrations which occur during the development of this part of the brain have been worked out by this method. The main results obtained are described in the article.

Animals↗
PubMed1992

Monoclonal antibodies specific to quail embryo tissues: their epitopes in the developing quail embryo and their application to identification of quail cells in quail-chick chimeras.

Quail-chick chimeras have been used extensively in the field of developmental biology. To detect quail cells more easily and to detect cellular processes of quail cells in quail-chick chimeras, we generated four monoclonal antibodies (MAb) specific to some quail tissues. MAb QCR1 recognizes blood vessels, blood cells, and cartilage cells, MAb QB1 recognizes quail blood vessels and blood cells, and MAb QB2 recognizes quail blood vessels, blood cells, and mesenchymal tissues. These antibodies bound to those tissues in 3-9-day quail embryos and did not bind to any tissues of 3-9-day chick embryos. MAb QSC1 is specific to the ventral half of spinal cord and thymus in 9-day quail embryo. No tissue in 9-day chick embryo reacted with this MAb. This antibody binds transiently to a small number of brain vesicle cells in developing chick embryo as well as in quail embryo. A preliminary application of two of these MAb, QCR1 and QSC1, on quail-chick chimeras of neural tube and somites is reported here.

Animals↗
PubMed1992

Distribution analysis of transferred donor cells in avian blastodermal chimeras.

Blastodermal chimeras were constructed by transferring quail cells to chick blastoderm. Contribution of donor cells to host were histologically analyzed utilizing an in situ cell marker. Of the embryos produced by injection of stage XI-XIII quail cells into stage XI-2 chick blastoderm, more than 50 percent were definite chimeras. The restriction on the spatial arrangement of donor cells was induced by varying the stage of host. Ectodermal chimerism was limited to the head region and no mesodermal chimerism was shown when the quail cells were injected into stage XI-XIII blastoderm. Mesodermal and ectodermal chimerisms were limited to the trunk, not to the head region, when the quail cells were injected into the stage XIV-2 blastoderm. In these chimeras, however, some of the injected quail cells formed ectopic epidermal cysts. Consequently, the stage XIV-2 blastoderm may become intolerant of the injected cells. Our results suggest that it is possible to obtain chimeras that have chimerism limited to a particular germ layer and region by varying the stage of donor cell injection. Injected quail cells contributed to endodermal tissues and primordial germ cells regardless of the injection site. The quail-chick blastodermal chimeras could be useful in the production of a transgenic chicken and in the investigation of immunological tolerance.

Animals↗
PubMed1991

Production of quail-chick chimaeras by blastoderm cell transfer.

1. Quail-chick chimaeras were produced by injecting dissociated quail blastoderm cells into chick embryos. 2. Quail blastoderms were removed from the yolk and the cells were dispersed by trypsin treatment or pipetting. The cell suspension (1 to 5 microliters) was injected into the subgerminal cavity of unincubated chick embryos. The chick embryos were then cultured in recipient eggshells. 3. Quail blastoderm cells injected into the chick embryos adhered to the chick embryonic cells. The rates of hatching were 8.6% (38 chicks from 441 eggs) and 40.3% (48 chicks from 119 eggs) when the volumes of the cell suspension injected were 3 to 5 microliters and 1 microliter, respectively. 4. Seven out of 86 hatched birds were clearly identified as being chimaeric because part of the feather colouring was of quail specificity. In addition to these chimaeric birds, there were 8 chimaeric embryos which died before hatching. The distribution patterns of the quail feathers were varied among the chimaeric birds and embryos. 5. This technique provides a basis for the investigation of chick embryo cryopreservation, genetic transformation and analysis of cell lineage of chickens.

Animals↗
PubMed1990

Pathfinding during spinal tract formation in the chick-quail chimera analysed by species-specific monoclonal antibodies.

In order to analyse the spinal tract formation at early stages of development in avian embryos, chick-quail spinal cord chimeras were prepared and species-specific monoclonal antibodies (MAb) were developed. MAbs CN, QN and CQN uniquely stained chick, quail, and both chick and quail nervous tissues, respectively. All three antibodies appeared to bind to the same membrane molecule, but to different epitopes. Cord reversal revealed the features of axonal growth of both cord interneurons and dorsal root ganglion cells. Quail cord interneurons grew along an originally ventral marginal layer in the quail cord transplanted in a reversed position, then turned toward the ventral side at the boundary between the graft and the host, and grew along the host chick ventral marginal layer. Central axons of dorsal root ganglia were restricted to the ventrolateral region of the cord which originally formed the dorsal funiculus. These results suggest that cord interneurons and dorsal root ganglion cells actively select to grow along specific regions of the cord and that spinal tract formation appears to be determined by cord cells, and not by sclerotome cells.

Animals↗
PubMed1989

Avian spinal cord chimeras. Further studies on the neurological syndrome affecting the chimeras after birth.

These experiments bring new information concerning the immunological status after birth of quail----chick spinal cord chimeras. Such birds have been produced using recipient flocks of chickens different from those in our previous experiments. The breakdown of tolerance after hatching has been recorded and found to vary with the origin of the embryos. Chickens of broiler JA 657 strain and of a white leghorn strain raised in Japan started to exhibit signs of neural graft rejection later in life than the white leghorn chickens from a French breeder used in our previous studies. As previously described, in two animals, long-term tolerance was observed only for allogeneic chick----chick neural tube grafts. In one chimera the neurological syndrome resulting from rejection was reversible, and no signs of immune attack of the grafted central nervous tissue could be detected at sacrifice. This and other observations reported in this article strongly support the contention that the host immune response to foreign neural tissues starts in peripheral nerves and ganglia where no blood-brain barrier exists rather than in the spinal cord. A humoral response of the host against non-polymorphic quail antigens present on fibroblasts was observed in all birds at the time of rejection.

Animals↗
PubMed1989

Monoclonal antibodies against species-specific antigens in the chick central nervous system: putative application as transplantation markers in the chick-quail chimera.

With the recent progress in transplantation of neuronal tissues, cellular markers are needed to distinguish the grafted cells from the host. To generate monoclonal antibodies (MAb) recognizing species-specific antigens in the chick nervous system, we immunized mice with chick optic nerves and obtained 2 MAb which bind to chick but not to quail neural tissues. MAb-39B11 recognizes the cell surface antigen on the nerve fibers. MAb-37F5 recognizes the cytoplasmic components in several cell types, including ependymal cells and some large neurons. The utility of these MAb as markers for chick cells in the chick-quail chimeric brain and their advantages over conventional markers are discussed.

Animals↗
PubMed1986

Postnatal development of a demyelinating disease in avian spinal cord chimeras.

Xenogeneic spinal cord chimeras were constructed by grafting fragments of quail neural primordium into chick embryos at 2 days of incubation. Hatched birds displayed normal motor behavior for about 5 to 7 weeks, whereupon they developed a neurological syndrome; in the grafted spinal cord the pathological signs of the disease were very similar to those of the active plaques of multiple sclerosis and of the lesions of experimental allergic encephalomyelitis and neuritis, including Ia expression by brain capillary endothelia, rupture of the blood-brain barrier, leukocytic infiltration in the nervous tissue, and demyelination. In the animals at the most advanced stage of the disease an autoimmune attack occurred on the host's nervous system with the same histopathological signs.

Animals↗
PubMed1986

Studies on a protein kinase inhibitor-insensitive, phospholipase C-sensitive pathway of lipolysis in rat adipocytes.

Endogenous lipid droplets were prepared by subjecting fat cells to hypotonic shock and Triton X-100 treatment. The endogenous lipid droplets were found to show lipolysis in response to epinephrine, but not to show lipogenesis from glucose in response to insulin. These results indicated that the preparation of endogenous lipid droplets did not contain any intact fat cells capable of insulin-stimulated lipogenesis. Results with these endogenous lipid droplets showed that protein kinase inhibitor inhibited protein kinase-mediated hormone-sensitive lipase activity but did not reduce epinephrine-induced lipolysis. Cyclic AMP and dibutyryl cyclic AMP induced lipolytic activity in the presence of 80 mM KCl and their activities were not inhibited by protein kinase inhibitor. Phospholipase C inhibited epinephrine, cyclic AMP and dibutyryl cyclic AMP-induced lipolysis, but did not affect the lipolytic activity of either the activated or non-activated form of hormone-sensitive lipase. These results indicate the existence of a protein kinase inhibitor-insensitive and phospholipase C-sensitive lipolytic pathway in rat adipocytes.

Adipose Tissue↗
PubMed1985

Avian spinal cord chimeras. I. Hatching ability and posthatching survival in homo- and heterospecific chimeras.

Quail-chick spinal cord chimeras were constructed by grafting isotopically, at the brachial level, the neural tube of a quail embryo into a chick of the same developmental stage. The chimeras were allowed to hatch and their behavior and survival after birth were observed. We found that if white Leghorns of the rapid-feathering strain were taken as hosts, the ability of the operated embryos to hatch was higher than in the slow-feathering wild-type chickens. The important point arising from this study is that the establishment of the neuronal circuits and of the connexions of the grafted neurons to their peripheral and central targets occurs between cells of two different species in such a way that normal behavior of the chimera is ensured. These animals can stand, walk, and fly as normal chickens do. Moreover, the size reached by the fragment of quail spinal cord implanted into the chick axial structures is larger than it would have been in the donor at the same age. This results in perfectly normal morphogenesis of the vertebrae which develop from the chick somites at the level of the graft. The pigment pattern of the chick feathers colonized by quail melanoblasts of graft origin is very close to that of the quail, albeit somewhat different, probably due to the different size of the feathers in the two species. Normality of the chimeras is only transient. During the second month of their life they develop a neurological syndrome characterized first by the paralysis of the wings and later by their inability to stand. In strong contrast, spinal cord chimeras constructed between two histoincompatible chickens, remain healthy and seem to develop a complete tolerance to the graft. What seems to be the development of an immune rejection of the grafted neural tube in the quail-chick spinal cord chimeras is now under investigation.

Animals↗
PubMed1985

Effect of alkaline cations on cyclic 3' 5'-AMP stimulated lipolysis in rat adipocytes.

In Krebs-Ringer phosphate medium, cyclic AMP had little effect on production of free fatty acids by fat cells in vitro, whereas dibutyryl cyclic AMP or epinephrine stimulated the production of free fatty acids. On the other hand, although under non-physiological condition, cyclic AMP was found to stimulate the lipolysis in simple KCl-Tris medium. The stimulation level was similar to that elicited by dibutyryl cyclic AMP. Cyclic AMP also stimulated lipolysis in LiCl-Tris or RbCl-Tris medium, but not in NaCl-Tris medium. In KCl-Tris medium, addition of divalent alkaline cations (Mg2+, Ca2+ and Sr2+, at 40 mM) completely inhibited the stimulation by cyclic AMP, but not those by dibutyryl cyclic AMP and epinephrine. No cyclic AMP-induced lipolysis was observed in homogenized or freeze-thawed cells.

Adipose Tissue↗
PubMed1978

Effects of testosterone and orchiectomy on the development of gonadotrophs in neonatal rats with hypophysial stalk section.

The development of gonadotrophs in newborn Sprague-Dawley rats subjected to a hypophysial stalk section (SS) by an electrical cauterization of the infundibulum of the hypothalamus was examined throughout the first 12 postnatal days. The electrical cauterization of the infundibulum was performed during 24 to 30 h after birth, and the pituitaries were studied by immunohistochemical procedures 11 days later. In several animals orchiectomy or an administration of testosterone propionate (TP) was performed simultaneously with the cauterization. The SS animals showed remarkable retardation in body growth and in pituitary development. In males the development of gonadotrophs was strongly suppressed in number and in size after the cauterization, whereas in females the suppression was less prominent. Orchiectomy promoted the development of gonadotrophs in the SS males, while TP administration suppressed it in the SS females. These findings indicate that there is sexual difference in the neonatal development of gonadotrophs even in the pituitary isolated from the hypothalamus and that testosterone inhibits the development of gonadotrophs at the level of the hypophysis during the neonatal period in rats.

Animals↗