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Biomedical subjects

S Shinozuka

Publications and source records attributed to S Shinozuka.

16 recordsLinked to original sources
PubMed1995

Zona manipulation in an assisted reproductive technologies (ART) programme.

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.

Female↗
PubMed1994

Microsurgical anatomy of the cavernous sinus.

The cavernous sinuses of 50 adult cadavers were examined to investigate the relationships of the blood vessels and cranial nerves, important structures during surgery in this sinus. The first and second divisions of the fifth cranial nerve were embedded in the deep dural layer of the cavernous sinus and were supplied by the two main branches of the intracavernous carotid artery. The meningohypophyseal artery supplied the sixth cranial nerve in Dorello's canal and the third and fourth cranial nerves where they entered the dura. The inferolateral trunk supplied the third, fourth, fifth, and sixth cranial nerves. The size of the meningohypophyseal artery was usually inversely proportional to the size of the inferolateral trunk. The capsular artery did not supply the cranial nerves. The cavernous sinus can be approached through various routes: a) superior, through the anteromedial or medial triangle; b) lateral, through the paramedial, Parkinson's, anterolateral, and lateral triangles; c) inferior, through the posterolateral and posteromedial triangles; and d) from the inferomedial walls. The choice of surgical approach depends mainly on the location of the lesion to be treated.

Carotid Arteries↗
PubMed1986

Mechanism of renal peritubular extraction of plasma glutathione. The catalytic activity of contralumenal gamma-glutamyltransferase is prerequisite to the apparent peritubular extraction of plasma glutathione.

To clarify the peritubular mechanism for renal handling of plasma glutathione (GSH), variation of GSH levels in plasma, urine, kidney and liver was examined after intravenous administration of GSH to three groups of animals; control, acivicin-treated and rats treated with buthionine sulfoximine (BSO). Treatment of animals with BSO, a potent inhibitor of de novo GSH synthesis, markedly reduced hepatorenal GSH levels. Acivicin did not affect these levels. Upon intravenous injection of GSH (0.1 mmol/kg), renal GSH levels did not appreciably change in any of three animal groups. The rate of GSH disappearance from the circulation was rapid in control and BSO-treated rats, while it was markedly retarded in animals whose renal gamma-glutamyltransferase was extensively inactivated by acivicin. At 30 min after administration a significant amount of injected GSH was localized extracellularly (urine and plasma) in acivicin-treated animals. By contrast, most of the GSH rapidly disappeared from the extracellular space in control and BSO-treated animals. Together with the immunocytochemical evidence for the peritubular gamma-glutamyltransferase [Spater, H.W., Poruchynsky, M.S., Quintana, N., Inoue, M. & Novikoff, A.B. (1982) Proc. Natl Acad. Sci. USA 79, 3547-3550] the present results are fully consistent with the contention that the catalytic function of this enzyme is principally responsible for the peritubular mechanism for the renal handling of plasma GSH.

Animals↗
PubMed1979

Lactose intolerance associated with cataracts.

A 50-day-old boy with severe lactose intolerance is described. In addition to vomiting, failure to thrive, dehydration, metabolic acidosis and amino aciduria, bilateral cataracts were also found. At three months of age, a computerized axial tomography scan and an electroencephalogram were abnormal, and myoclonic spasms began at the age of seven months.

Cataract↗
PubMed1979

Iatrogenic and transient hyperglycinemia in patients with phenylketonuria.

Two patients with phenylketonuria detected by newborn screening for inborn errors of metabolism were treated with low phenylanine formulae. Serum phenylalanine levels were well controlled, but serum glycine levels were elevated until 4 or 5 months of age. This was probable due to the high content of glycine in the formulae. Glycine level returned to be normal in these patients, even though they were kept on the same formula, suggesting, immature metabolism of glycine during this period. No clinical problems were encountered in either patient.

Glycine↗
PubMed1979

Lysine intolerance in a variant form of citrullinemia.

An oral loading of lysine (100 mg of lysine-HCL/kg was performed in two patients, 18-and 23-yr-old, with a variant form of citrullinemia. Serum citrulline levels were approximately 10 times higher than control level and lysine levels were within the normal range, in contrast to the classical form of the disease in which serum citrulline is approximately 100 times normal levels and hyperlysinemia is usually present. After lysine loading, lysine levels rose sharply and clearance was decreased. Blood ammonia rose approximately 2.5 times. Lysine, citrulline, and arginine were markedly elevated in urine, collected 90--210 min after the lysine loading. Baseline homocitrulline and homoarginine excretion was elevated and increased further after the load.

Adolescent↗
PubMed1978

Methylmalonic acidemia.

A patient presenting with severe metabolic acidosis accompanied by hyperglycinemia, hyperuricemia, hypoglycemia and hypertammonemia is described. Metabolic acidosis was found to be due to accumulated methylmalonic acid and did not respond to vitamin B12 administration. The patient showed favorable growth and development when kept on a low isoleucine, methionine, threonine and valine diet. In vitro studies using a lymphoid cell line derived from the patient showed a deficiency of methylmalonyl-CoA carbonyl-mutase.

Acidosis↗