[In vitro culture and transfer of mammalian early embryos].
Explore the source record for details and available documents.
Animals↗
Biomedical subjects
Y Toyoda
Publications and source records attributed to Y Toyoda.
[Dynamic cardiomyoplasty for chronic heart failure induced by femoral arteriovenous shunt: preliminary report].
Explore the source record for details and available documents.
Animals↗
Sperm from mice carrying a targeted mutation of the acrosin gene can penetrate the oocyte zona pellucida and effect fertilization.
The physiological function of mammalian sperm acrosin has long been believed to be involved in the limited proteolysis of the oocyte zona pellucida, thus enabling the sperm to penetrate this extracellular matrix and to gain access to the oocyte plasma membrane. Here we show that male mice homozygous for a targeted mutation in the mouse acrosin gene are still fertile in spite of the complete absence of acrosin protease activity in the sperm. In vitro fertilization assays verified that sperm from the homozygous mutant mice penetrate the zona pellucida and effect fertilization. Therefore, acrosin is not essential for both sperm penetration of the zona pellucida and fertilization.
Acrosin↗
Evidence for glucokinase translocation by glucose in rat hepatocytes.
By an immunohistochemical technique, we examined changes in the subcellular distribution of rat liver glucokinase in response to external stimuli. Glucokinase immunoreactivity was found predominantly in the nucleus of hepatocytes. In situ perfusion of the liver with 20 mM glucose for 10 min caused a marked decrease in nuclear immunoreactivity and an increase in cytoplasmic immunoreactivity. Insulin (10 nmol/l) potentiated this glucose effect. However, no change took place when 5 mM glucose was perfused. These results indicate that glucokinase is translocated from the nucleus to the cytoplasm in response to a high concentration of glucose.
Animals↗
No dosage effect of recombinational hotspots in the mouse major histocompatibility complex.
The sites of meiotic recombination in the proximal region of the mouse major histocompatibility complex (MHC) are clustered at hotspots. Some MHC haplotypes derived from Asian wild mice increase the frequency of recombination at such hotspots when heterozygous with standard laboratory haplotypes. The wm7 and cas3 haplotypes have a hotspot close to the Lmp-2 gene (Lmp-2 hotspot), and the cas4 haplotype has a hotspot about 100 kilobase (kb) proximal, close to the Pb gene (Pb hotspot). To examine the effect of a double dose of hotspots, we estimated the rate of recombination and determined the location of the breakpoints in crosses of wm7/cas3 and wm7/cas4. In 3570 backcross progeny we identified 29 new recombinants in the H-2K to Ab interval, at a frequency of 0.81%. This frequency is 40-fold higher than in crosses between laboratory haplotypes and very similar to those previously obtained in crosses between these wild and standard laboratory haplotypes. Thus, a double dose of hotspots has no additive effect on the frequency of meiotic recombination. The site-specificity of recombination was also conserved. Twenty-three breakpoints were confined within 5.4 kb in the Lmp-2 hotspot, and six breakpoints from the cas4 cross were located in the Pb hotspot, which we have now confined to a 15 kb segment.
Animals↗
Recombination in the class III region of the mouse major histocompatibility complex.
The sites of meiotic recombination in the class II region of the mouse major histocompatibility complex (MHC) are clustered at hotspots. To search for hotspots in the class III region, we mapped recombinational breakpoints of 79 Ab:H2-D recombinants with 11 DNA markers; these included Tnx, the gene for an extracellular matrix protein, tenascin X, the Notch-related Int3 gene, and a microsatellite marker, D17Mit13, none of which had previously been mapped precisely. The results gave the gene order of Eb-61.1-Int3-Tnx-Cyp21/C4-Bf-Hsp68c-D17Mit13+ ++-Tnfa/Tnfb-D. The crossover sites in 40 of the 79 recombinants were confined within the Eb/Int3:Tnx/Cyp21 interval. The result demonstrated that an unequal distribution of recombination is a general feature of the mouse MHC, suggesting the presence of a recombinational hotspot within the Int3:Tnx interval.
Animals↗
Haematological improvement by long-term administration of recombinant human granulocyte-colony stimulating factor and recombinant human erythropoietin in a patient with severe aplastic anaemia.
A 6-year-old girl with post-hepatitic severe aplastic anaemia was referred to our hospital. Haematological examination showed a haemoglobin level of 5.2 g/dl, platelet count of 8,000/microliters, and white blood cell count of 130/microliters with 17% neutrophils. She was treated with recombinant human granulocyte-colony stimulating factor (15 micrograms/kg/day i.v.) and cyclosporin A (6 mg/kg/day p.o.). The absolute neutrophil count gradually increased, but Hb and platelets were not improved. The intravenous administration of recombinant human erythropoietin (100 U/kg three times a week) was started, and the reticulocyte count reached 20,000/microliters on day 12. The platelets increased to 81,000/microliters after 16 months of combined administration of recombinant human granulocyte-colony stimulating factor, recombinant human erythropoietin and cyclosporin A. After 20 months of combined administration, the haematological results were: Hb, 13.1 g/dl; platelets 80,000/microliters; WBC, 9500/microliters with 40% neutrophils. After recombinant human granulocyte-colony stimulating factor treatment, the myeloid elements of the bone marrow and the number of granulocyte-macrophage colony forming units increased. Bone marrow erythropoiesis and erythroid colonies also increased after recombinant human erythropoietin administration. The clinical course suggested a beneficial effect of haemopoietic growth factors and cyclosporin A in post-hepatitic aplastic anaemia.
Anemia, Aplastic↗
Tracheo-bronchial angles in infants and children.
Explore the source record for details and available documents.
Adult↗
Effects of nicardipine, nitroglycerin, and nitroprusside on left ventricular diastolic function during enflurane anesthesia.
The purpose of this study was to evaluate the effects of nicardipine (NCR), nitroglycerin (NTG), or nitroprusside (SNP) on left ventricular diastolic function during enflurane anesthesia in acutely instrumented dogs. Using echocardiography, time constants for the decline in isovolumic left ventricular pressure (T), stiffness constant (K), diastolic time intervals, and left ventricular filling rates were measured in 21 mongrel dogs during the following conditions: (1) 0% enflurane (control), (2) 3.3% enflurane, (3) intravenous infusion of NCR, 1 microgram/kg/min, NTG, 2 micrograms/kg/min, or SNP, 2 micrograms/kg/min, during 3.3% enflurane, and (4) intravenous infusion of NCR, 2 micrograms/kg/min, NTG, 4 micrograms/kg/min, or SNP, 4 micrograms/kg/min, during 3.3% enflurane. During 3.3% enflurane anesthesia, T and K increased significantly, and left ventricular filling rates decreased. The administration of NCR, NTG, or SNP returned T and K to control levels. Left ventricular rapid filling rate returned toward the control level only with NCR (P < 0.05, NCR v NTG, SNP). It is concluded that the depression of diastolic function during enflurane anesthesia was improved by NCR or other vasodilators. The extent and mechanism of action of these vasodilators might differ, however.
Anesthesia, Inhalation↗
Purification of rat liver glucokinase.
A new purification method for rat liver glucokinase was developed. Glucokinase was purified to homogeneity in a yield of 70% in 5 days. The procedure consists of DEAE-cellulose ion-exchange chromatography, QAE-Toyopearl ion-exchange chromatography, glucosamine-Sepharose affinity chromatography, and HiLoad Superdex 200 gel filtration. Purified glucokinase had a specific activity of 200 units/mg protein and was highly stable in the presence of 100 mM glucose, 300 mM KCl, and 20% glycerol. We found that some of the methionine residues of glucokinase were oxidized to methionine sulfoxide residues during dialysis in the presence of glucose. It would appear that this oxidation is caused by formation of hydroxyl radicals in the presence of glucose and contaminating transition metal(s).
Animals↗
Apoptosis induced in mouse hepatitis virus-infected cells by a virus-specific CD8+ cytotoxic T-lymphocyte clone.
Morphological changes of mouse hepatitis virus-infected J774.1 cells cocultured with cloned mouse hepatitis virus-specific CD8+ cytotoxic T lymphocytes were examined by electron microscopy. Condensation and margination of chromatin, cellular shrinkage with severe vacuolar degeneration, and blebbing were observed. In addition, fragmentation of cellular DNA was observed, and a decrease in virus titer was accompanied by those changes. These findings show that the cloned cytotoxic T lymphocytes induce in the target cell an internal degradation program termed apoptosis, which results in virus clearance.
Animals↗
Nasal intubation with Bullard laryngoscope: a useful approach for difficult airways.
Since the original technique using the Bullard laryngoscope requires considerable practice to be reliable, we have developed an easier method with a directional-tip endotracheal tube through the nostril. We first examined the feasibility of our method in patients with or without difficult airways. All 26 patients with difficult airways were successfully tracheally intubated with our method, and times for visualization and intubation were not different from those in 10 patients with normal airways. We further examined the direction of the tips of endotracheal tubes through the nostril in 128 patients with normal airways using four combinations of two kinds of both laryngoscopes (Bullard and Macintosh) and endotracheal tubes (directional-tip tube: Endotrol, Mallinckrodt Laboratories, Athlone, Ireland; or straight distal-end tube: Blue Line, Portex Ltd., Hythe Kent, United Kingdom). We found that a combination of the Bullard laryngoscope and the Endotrol tube had a higher probability of accessing the center of the glottis than the others. In conclusion, nasal insertion of a directional-tip tube assisted by the Bullard laryngoscope is an assured and prompt procedure for intubating the tracheas of patients with difficult airways.
Adult↗
Glycosaminoglycans prevent induction of fragmentation of porcine oocytes stimulated by dibutyryl cyclic adenosine 3',5'-monophosphate in culture.
The in vitro effects of derivatives of cyclic adenosine 3',5'-monophosphate (cAMP) and glycosaminoglycans (GAGs) on the spontaneous induction of fragmentation of cultured porcine oocytes were examined. Oocytes cultured for 72 h or longer undergo spontaneous fragmentation, and the percent of fragmented oocytes increased thereafter. The fragmented oocytes consisted of several "blastomeres" showing uneven distribution of DNA among the "blastomeres". Cytoplasmic bodies were also identified on the surface of fragmented oocytes and in the space among fragmented "blastomeres". Dibutyryl cyclic adenosine 3',5'-monophosphate (dbcAMP) at concentrations exceeding 50 microM markedly increased the induction of fragmentation. 8-bromoadenosine 3',5'-cyclic monophosphate, butyrate, cAMP and GAGs isolated from porcine follicular fluid (pFF) did not stimulate the induction of fragmentation. pFF-GAGs added to the suspending medium at concentrations of 10 micrograms/ml or greater prevented the occurrence of dbcAMP-stimulated fragmentation of isolated porcine oocytes in a dose-dependent manner. Preparations of hyaluronic acid and chondroitin sulfate from a commercial source prevented the occurrence of fragmentation stimulated by dbcAMP. The present findings suggest that cAMP may involve the induction of fragmentation of porcine oocytes and GAGs prevent the activation of cAMP-dependent fragmentation.
Animals↗
Limitations of panoramic radiography in the detection of bone defects in the posterior wall of the maxillary sinus: an experimental study.
Some lesions in the maxillary sinus may be adequately detected by panoramic radiography. The present study was designed to evaluate the ability of panoramic radiography in detecting experimental bony defects in the posterior wall of the maxillary sinus by comparison with Waters' projection and CT. Bony defects in the mediosuperior and medioinferior regions of the posterior wall were readily detected by panoramic radiography, but those in the laterosuperior or centre were not. It is concluded that there are limitations to the detection of bony defects in the posterior wall of the maxillary sinus by panoramic radiography alone. It is recommended that this technique should not be used for the detection of small osteolytic lesions in the maxillary sinus.
Evaluation Studies as Topic↗
A restriction fragment length polymorphism of a p53-related sequence in rat (Rattus norvegicus).
Polymorphisms of the p53 tumor-suppressor gene and its related sequences were investigated among inbred rat strains. In a series of Southern blot hybridizations using the human p53 cDNA probe with various restriction endonucleases, HindIII digests and PstI digests showed interstrain variation in the length of hybridizing fragments. Distribution of the HindIII variant fragments among 17 inbred rat strains was identical with that of PstI variant fragments. The variant fragments were segregated as codominant alleles in backcross progeny, and the locus for this restriction fragment length polymorphism of the p53-related sequence was found to correspond to a p53-related sequence located on rat chromosome 9.
Alleles↗
The effect of pig follicular fluid fractions on cumulus expansion and male pronucleus formation in porcine oocytes matured and fertilized in vitro.
The aim of this study was to analyse the substance(s) present in porcine follicular fluid that promotes cumulus expansion and male pronucleus formation in pig oocytes matured and fertilized in vitro. The follicular fluid was separated into four fractions by ultracentrifugation at 220,000 g at 10 degrees C for 48 h. Oocyte-cumulus-cell complexes obtained from prepubertal gilts were cultured in vitro for 48 h in each of the fractions after reconstitution with a modified Krebs-Ringer bicarbonate solution. Each fraction containing oocyte-cumulus complexes was then fertilized in vitro with frozen-thawed and preincubated epididymal boar spermatozoa. After 24 h of culture, oocytes that matured in fraction 1 showed a marked expansion of the surrounding cumulus, as did those matured in pig follicular fluid. However, complexes cultured in the remaining fractions exhibited very little or no expansion. No difference was observed in the degree of expansion caused by follicular fluid collected from small, medium or large follicles. Further analysis of fraction 1 by HPLC gave several subfractions, one of which (22) induced a significantly greater expansion of the cumulus than did others (P < 0.01). Fraction 1 also induced higher rates of male pronuclei formation (62%) than did fractions 2, 3 and 4 (22%, 35% and 30%, respectively). The rate of male pronuclei formation in pig follicular fluid from large follicles was significantly lower (33%) than in fluid from small or medium follicles (89% and 78%, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Localization of a N-ras-related sequence on rat chromosome 1.
Location of the locus for a restriction fragment length polymorphism of N-ras-related sequences (NRAS2) on the rat chromosome 1 was determined by linkage analysis using a microsatellite locus (KAL) and a coat-color locus (C). The recombination frequencies between NRAS2 and C, NRAS2 and KAL, and C and KAL in 57 backcross progeny obtained from crosses of (WKS/Iar x IS/Iar) x WKS/Iar were 7.0 +/- 3.4%, 28 +/- 5.9%, and 23 +/- 5.6%, respectively. The order of the three loci on the rat chromosome 1 was determined as follows: KAL-C-NRAS2.
Animals↗