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Biomedical subjects

Y Toyoda

Publications and source records attributed to Y Toyoda.

At least 199 records · Page 11Linked to original sources
PubMed1994

[Injury of the coronary artery following non-penetrating chest trauma--a case report].

A previously healthy 71-year-old man sustained a non-penetrating chest trauma. The chest CT scan revealed cardiac tamponade and then emergent operation was performed. We opened the pericardium through median sternotomy and found a laceration of the distal left anterior descending coronary artery (seg. 8). We ligated the artery and he showed signs of a limited myocardial infarction on the postoperative ECGs, but echocardiography revealed symmetric contraction and normal ejection fraction. His postoperative course was uneventful. We think that injuries of distal coronary arteries could be successfully ligated.

Aged↗
PubMed1993

PCR sexing and developmental rate differences in preimplantation mouse embryos fertilized and cultured in vitro.

A two-step polymerase chain reaction (PCR) assay was used to determine the sex of mouse preimplantation embryos obtained from oocytes fertilized and cultured in vitro, to investigate the differences in the developmental rates of mouse embryos according to the sex. All the in vitro developed embryos could be analyzed by this method. When the embryos were classified according to the time of morula to blastocyst transition as fast-intermediate- and slow-growing embryos, a significantly high percentage (78.0%) of the fast-developing embryos were identified as males; while a significantly lower percentage (42.5%) of slow-developing embryos were identified as males. The intermediate-developing embryos presented a sex ratio not significantly different from the total (57.5%). The deviation of sex ratio was further confirmed by embryo transfer experiment, where fast- and slow-developing embryos gave 76.2% and 25.7% male fetuses, respectively. We concluded that male mouse embryos fertilized and cultured in vitro develop faster than female embryos.

Animals↗
PubMed1993

Morphological profiles of mouse ovarian follicles: extensive accumulation of a strongly negative-charged substance at specific foci in follicular tissue during oocyte maturation.

Structural changes in cumulus-oocyte complexes and granulosa cells were induced by administering pregnant mare serum gonadotropin (PMSG) and human chorionic gonadotropin (hCG) to female mice. Three and 9 h after hCG administration, dissolution of the germinal vesicle (GVBD) and progression to the second metaphase occurred respectively in oocytes. The number of cumulus cells associated with the granulosa cell layer decreased significantly 1 h after hCG administration. Expansion of cumulus cell investment was due to the abundant deposition of intercellular materials in the cumulus-oocyte complexes during oocyte maturation. A strongly negative-charged (colloidal iron-positive) substance was detected in the intercellular spaces of follicular tissue, especially in the cumulus mass. Moreover, cells located where the cumulus mass and granulosa cell layer intertwined became enlarged during the resumption of the meiosis of oocytes. Colloidal iron-positive substances accumulated extensively within the intercellular spaces of the enlarged cells.

Animals↗
PubMed1993

Inhibition of glucose-induced insulin secretion through inactivation of glucokinase by glyceraldehyde.

D-Glyceraldehyde irreversibly inhibited rat liver glucokinase in a concentration-dependent manner. The inactivation of glucokinase by glyceraldehyde was blocked by the presence of its substrates such as glucose and mannose. Glucokinase was highly sensitive to glyceraldehyde compared with some other glycolytic enzymes (from animal tissues) including hexokinase, glucose-6-phosphate isomerase, 6-phosphofructokinase, glyceraldehyde-3-phosphate dehydrogenase, and pyruvate kinase. The amino acid analysis of untreated and glyceraldehyde-treated glucokinase suggested that glyceraldehyde-induced inactivation of glucokinase is caused by glycation of Lys residues of the enzyme by the triose. Treatment of pancreatic islets with 6 mM glyceraldehyde for 1 h at 37 degrees C caused both inactivation of glucokinase and inhibition of glucose-induced insulin secretion. Another glucose-phosphorylating enzyme (hexokinase) in pancreatic islets, however, was little affected by glyceraldehyde. In addition, glyceraldehyde did not affect the insulin secretory responses of islets to nonglucose secretagogues such as glyceraldehyde and Leu. When pancreatic islets were cultured with a lower concentration (1 mM) of glyceraldehyde for a longer time (17 h) in the presence of 10 mM glucose to mimic the in vivo conditions, both glucokinase activity and glucose-induced insulin secretion were again decreased. This study demonstrates that glucose-induced insulin secretion is impaired by glyceraldehyde through the inactivation of glucokinase. The implication of this finding in the pathophysiology of type II diabetes is discussed.

Amino Acids↗
PubMed1993

Identification of inbred rat strains by using DNA fingerprinting method.

DNA fingerprinting method was applied to identify inbred strains of laboratory rats. By Southern blot hybridization with core sequence of minisatellite DNA as a probe, typical hypervariable patterns of DNA fingerprint were obtained in inbred rat strains. The patterns were completely different among 15 rat strains examined, and the patterns of the DNA fingerprint of samples obtained from the same strain were completely identical. The patterns of the DNA fingerprint of two substrains derived from the same strain were identical, indicating relative stability of the patterns over a large number of generations. Therefore, we concluded that the DNA fingerprinting method was useful for the identification of inbred strains in genetic monitoring of laboratory rats.

Animals↗
PubMed1993

[Blalock-Taussig shunts in infants less than 6 months of age with special reference to the long-term administration of prostaglandin E1].

Classical Blalock-Taussig (B-T) shunt operation was performed in 14 neonates (group N) and 22 infants (group P). A mean age of group N patients was thirteen days and that of group P patients was two months. Preoperatively prostaglandin E1 (PGE1) was administered in all patients and was continued for a mean of 7 days (range 2 hours to 21 days) in group N, and a mean of 78 days (range 42 to 158 days) in group P. Body weight (4359 +/- 339 g), size of subclavian artery (3.7 +/- 0.5 mm in diameter) and size of pulmonary artery (6.4 +/- 1.2 mm in diameter) at operation of group P patients were larger than those (3212 +/- 490 g, 3.4 +/- 0.4 mm, 5.1 +/- 1.3 mm) of group N. But there were no differences in operation time (165 +/- 22 minutes in group N vs 174 +/- 25 minutes in group P) and clamp time of pulmonary artery (31 +/- 10 minutes in group N vs 30 +/- 5 minutes in group P) between 2 groups. There was no operative death in both groups. There were one late death in group N and three late death in group P. Five patients in group N and nine patients in group P required additional B-T shunt at the mean follow up interval of two years.(ABSTRACT TRUNCATED AT 250 WORDS)

Alprostadil↗
PubMed1993

In vitro maturation and fertilization of preovulatory dog oocytes.

Mature beagle bitches were injected with exogenous gonadotrophins to induce superovulation. Preovulatory oocytes were collected at 72 h after intravenous injection of human chorionic gonadotrophin and cultured for 72 h in a modified Krebs-Ringer bicarbonate solution containing 10% fetal calf serum and 30 mg gentamicin sulfate l-1. Control oocytes were collected from ovaries of anoestrous bitches and cultured for 72 h. All oocytes were at the germinal vesicle stage when collected. At 72 h of culture, a significantly larger population (31.9%) of preovulatory oocytes reached metaphase II, compared with the control group (12.1%). Ejaculated beagle spermatozoa were washed and preincubated for 4 h, then capacitated spermatozoa were added to the oocytes. The kinetics of sperm penetration into the ooplasm did not differ between the two groups of oocytes, but the development of male and female pronuclei was observed more frequently in oocytes collected from preovulatory follicles. These results suggest that preovulatory maturation is required for the normal development of canine oocytes, although they are ovulated at the germinal vesicle stage.

Animals↗
PubMed1993

[Effects of sevoflurane on hemodynamics during the induction of anesthesia compared with those of isoflurane, enflurane and halothane].

The effects of sevoflurane (S), isoflurane (I), enflurane (E) and halothane (H) on hemodynamics were studied in 50 patients during the inhalation of 1.5 MAC of each anesthetic before the surgery. Mean arterial pressure (MAP), heart rate (HR), cardiac index (CI), systemic vascular resistance index (SVRI) and stroke volume index (SVI) were measured noninvasively using the automatic blood pressure manometer and the ultrasonic Doppler method (Accucom). There were significant differences between E and H in MAP, CI, SVRI and SVI. The values of CI, SVRI, SVI with S, as well as with I, were between those of E and H. These results indicate that sevoflurane causes the depression of blood pressure mostly by decreasing afterload during the induction of anesthesia, although the decrement with sevoflurane, as well as that with isoflurane, is less than that with enflurane.

Adult↗
PubMed1993

Two interconvertible forms of glucose-6-phosphate isomerase in rat muscle.

Chromatography of crude rat muscle extracts on CM-cellulose resulted in separation of glucose-6-phosphate isomerase (GPI) into two active peaks (designated types I and II in order of elution). Incubation of type I and type II at pH 6.0, 7.0, or 8.0 in the presence and absence of KCI revealed that one type of GPI is converted to the other type under certain conditions and that the two types are interconvertible by changing the incubation conditions. The two types were similar in molecular weight, kinetic property, and optimum pH. A remarkable difference was observed in pH-activity profile: the activity of type I, but not type II, was detectable at pH 6-7. The present results suggest that rat muscle has two types of GPI which are interconvertible and that the two types may be conformational variants of the same enzyme. It is conceivable that the interconversion between the two types is related to the regulation of glycolysis at lower intracellular pHs.

Animals↗
PubMed1993

[Effect of enflurane on human somatosensory evoked potentials: differences between specific and nonspecific responses].

The effect of enflurane on somatosensory evoked potentials (SEP) was investigated in nine gynecological patients under nitrous oxide-enflurane anesthesia. SEPs were obtained from electrodes placed on the scalp C4 and earlobes by median nerve stimulation contralateral to the recording site. SEPs taken in a control study without enflurane consisted of six components; P12, N17, P23, N31, P50, and N65. Components N17, P23, N31, and P50, thought to be specific SEP responses, showed a dose-dependent increase in latencies under enflurane while P12, the initial SEP components, did not show any significant changes throughout the experiment. The longer the latency for a given response component, the greater was the increase in latency seen under enflurane anesthesia. On the other hand, N65, assumed to be a nonspecific SEP response, was completely lost with inhalation of 0.5 MAC or more of enflurane. However, the peak-to-peak amplitude between P23 and N31 was enhanced dose-dependently with enflurane up to 1.5 MAC. These results suggest that, at clinically effective doses, enflurane may inhibit nonspecific projection pathways while enhancing the primary cortical sensory area, and this enhancement may be responsible for provoking convulsive seizures under enflurane anesthesia.

Adult↗
PubMed1992

Tetraparental mice reveal complex cellular interactions of the mutant, autoimmunity-inducing lpr gene.

Lpr is a murine recessive autosomal mutant gene that, in conjunction with the background genes of different inbred mouse strains, produces varied syndromes of lymphadenopathy and autoantibody production. We have investigated the cellular basis of the lpr determined phenomena by constructing allophenic (tetraparental) chimeras of MRL/Mp-lpr/lpr combined with C57BL/6 and MRL/+ combined with C57BL/6-lpr/lpr. The appearance of lymphadenopathy, lpr atypical T cells, and autoantibodies was found to depend on the relative amounts +/+ and lpr tissue. The failure of these three abnormalities to correlate in certain animals suggested different pathways of lpr gene action. Furthermore, in the lpr predominant animals, both the lymphadenopathy and autoantibodies were essentially entirely contributed by the lpr donor. The expression of the lpr gene within the same cells expressing the MRL or B6 background determined the pathologic and serologic manifestations characteristic of the disease of that lpr strain, despite the presence of +/+ cells of the other background in the same individual. The lpr syndrome thus depends on the intracellular interaction of the lpr and background genes, and on positive signalling between different lpr cell populations.

Animals↗
PubMed1992

Inhibition of mutagenesis by p-aminobenzoic acid as a nitrite scavenger.

Nitrite treatment enhances the direct-acting mutagenicity of various foodstuffs (e.g., chicken, bloater, the soybean flour 'kinako', and Ban-Ban-Chi sauce) on Salmonella typhimurium TA100. p-Aminobenzoic acid (PABA) and glutathione (GSH) reduced this mutagenicity; on the other hand, thioproline (TPRO) increased it. PABA seemed more effective than TPRO in scavenging nitrite ion. In analysis of the reactions of PABA and sodium nitrite under acidic conditions (pH 3.0), p-hydroxybenzoic acid (PHBA) was identified as a major reaction product. The reaction seems to involve two steps, diazotization and diazonium substitution. PHBA was not mutagenic to four strains (TA97, TA98, TA100 and TA102) of S. typhimurium with or without S9 mix.

4-Aminobenzoic Acid↗
PubMed1992

Acute and late disease induced by murine coronavirus, strain JHM, in a series of recombinant inbred strains between BALB/cHeA and STS/A mice.

To examine the genetic control of acute and late disease induced by a murine coronavirus, strain JHM (JHMV), BALB/cHeA, STS/A, F1 hybrids and 13 recombinant inbred (RI) strains between BALB/cHeA and STS/A mouse strains were inoculated intracerebrally with 100 pfu of JHMV. All the BALB/cHeA mice died within 2 weeks from acute encephalitis. In contrast, STS/A mice were shown to be partially resistant, with a mortality rate of 30%, longer survival times and lower rates of viral production. The mortality rates, survival times and viral titers of F1 hybrids and the RI strains varied, suggesting involvement of multiple genes. STS/A, F1 hybrid and RI mice surviving the acute infection occasionally developed severe paraparesis about 1 month post-infection. In these mice, vacuolar degeneration, astrocytosis, the absence of perivascular cuffing and minimal demyelination were found in the central nervous system. No infectious virus could be recovered from these mice. Although the paralysis of delayed onset was limited to STS/A, F1 hybrid and eight of the 13 RI strains, the incidence varied significantly among the RI strains. These results may suggest that JHMV-induced late disease is also under multifactorial control. The pathogenesis of JHMV infection is discussed.

Acute Disease↗