Biomedical subjects

Y Nakaoka

Publications and source records attributed to Y Nakaoka.

At least 19 recordsLinked to original sources

PubMed2006

Successful delivery after the transfer of twice-vitrified embryos derived from in vitro matured oocytes: a case report.

We report here the first case of successful pregnancy and delivery after the blastocyst transfer of twice-vitrified embryos produced following in vitro maturation (IVM) and ICSI. The patient received 5000 IU hCG on day 12 of the treatment cycle, and oocyte retrieval was carried out 36 h after hCG injection. A total of 22 immature oocytes were obtained. Following incubation for 26 h in IVM medium, 15 oocytes (68.2%) reached metaphase II stage. In total, 13 oocytes (86.7%) were fertilized after ICSI with the husband's sperm, and 11 embryos at the pronuclear stage and two cleaved embryos on day 2 were vitrified because of thin endometrial thickness. Eight cryopreserved embryos at the pronuclear stage were warmed and cultured until the day 3 stage. Three embryos were transferred, and three embryos were twice vitrified. Unfortunately, these transferred embryos did not implant. Three twice-vitrified embryos were rewarmed and cultured until the day 5 stage, and two embryos were transferred. The second transfer attempt of twice-vitrified embryos resulted in the full-term delivery of a healthy infant. This case report demonstrates that twice-vitrified embryos, developed using an IVM protocol, retain the developmental competence for full-term, healthy infants.

Adult↗

PubMed2004

Phase I/II study of cisplatin combined with weekly paclitaxel in patients with advanced non-small-cell lung cancer.

To determine the maximum-tolerated dose (MTD) and the recommended dose (RD) of paclitaxel administered weekly with a fixed dose of cisplatin, and to assess the toxicity and activity of this combination, we conducted a phase I/II trial in patients with advanced non-small-cell lung cancer (NSCLC). In this study, patients with stage IIIB/IV NSCLC were eligible. Paclitaxel, at a starting dose of 40 mg x m(-2) week(-1) on days 1, 8, and 15, was combined with a fixed dose of cisplatin 80 mg x m(-2) on day 1. Chemotherapy was given in a 4-week cycle. In this phase I/II study, 38 patients were enrolled. Dose-limiting toxicities (DLT) were neutropenia, fatigue, and omission of treatment due to leucopenia, thrombocytopenia, or febrile neutropenia. The MTD and RD were estimated to be 70 mg x m(-2). Of the 37 assessable patients, 23 had a partial response and one had a complete response. Overall response rate was 62.1% (95% confidence interval (CI): 46.5-77.7%). The progression-free survival, the median survival time, and the 1-year survival rate were 5.5 months, 13.7 months, and 56.9%, respectively. This regimen is tolerable and very active against advanced NSCLC, and its efficacy should be confirmed in a phase III study.

Adult↗

PubMed2001

Activation of signal transducer and activator of transcription 3 protects cardiomyocytes from hypoxia/reoxygenation-induced oxidative stress through the upregulation of manganese superoxide dismutase.

BACKGROUND: Mice with cardiac-specific overexpression of signal transducer and activator of transcription 3 (STAT3) are resistant to doxorubicin-induced damage. The STAT3 signal may be involved in the detoxification of reactive oxygen species (ROS). METHODS AND RESULTS: The effects of leukemia inhibitory factor (LIF) or adenovirus-mediated transfection of constitutively activated STAT3 (caSTAT3) on the intracellular ROS formation induced by hypoxia/reoxygenation (H/R) were examined using rat neonatal cardiomyocytes. Either LIF treatment or caSTAT3 significantly suppressed the increase of H/R-induced ROS evaluated by 2',7'-dichlorofluorescin diacetate fluorescence. To assess whether ROS are really involved in H/R-induced cardiomyocyte injury, the amount of creatine phosphokinase in cultured medium was examined. Both LIF treatment and caSTAT3 significantly decreased H/R-induced creatine phosphokinase release. These results indicate that the gp130/STAT3 signal protects H/R-induced cardiomyocyte injury by scavenging ROS generation. To investigate the mechanism of scavenging ROS, the effects of LIF on the induction of antioxidant enzymes were examined. LIF treatment significantly increased the expression of manganese superoxide dismutase (MnSOD) mRNA, whereas the expression of the catalase and glutathione peroxidase genes were unaffected. This induction of MnSOD mRNA expression was completely blocked by adenovirus-mediated transfection of dominant-negative STAT3. Moreover, caSTAT3 augmented MnSOD mRNA and its enzyme activity. In addition, the antisense oligodeoxyribonucleotide to MnSOD significantly inhibited both LIF and caSTAT3-mediated protective effects. CONCLUSIONS: The activation of STAT3 induces a protective effect on H/R-induced cardiomyocyte damage, mainly by inducting MnSOD. The STAT3-mediated signal is proposed as a therapeutical target of ROS-induced cardiomyocyte injury.

Animals↗

PubMed2001

Bone morphogenetic protein-2 inhibits serum deprivation-induced apoptosis of neonatal cardiac myocytes through activation of the Smad1 pathway.

Bone morphogenetic protein (BMP)-2 has been shown to induce ectopic expression of cardiac transcription factors and beating cardiomyocytes in non-precardiac mesodermal cells, suggesting that BMP-2 is an inductive signaling molecule that participates in cardiac development. However, direct evidence of the effects of BMP-2 on cardiac myocytes has not been reported. To examine the role of BMP-2 and its receptors, we studied the ability of BMP-2 to promote survival of isolated neonatal rat cardiac myocytes. BMP receptors IA, IB, and II and activin receptor I were found to be expressed in myocytes, and BMP-2 phosphorylated Smad1 and p38 MAPK. Interestingly, BMP-2 promoted survival and inhibited apoptosis of serum-deprived myocytes, although it did not strongly induce hypertrophic growth. To explore the mechanisms for this protective effect, an adenovirus-based vector system was used. Similar to BMP-2, Smad1 promoted survival that was repressed by Smad6. Moreover, BMP-2 and Smad1 enhanced the expression of the anti-apoptotic molecule Bcl-x(L). Antisense oligonucleotides to bcl-x(L) attenuated the survival effected by BMP-2. Overall, our findings suggest that BMP-2 prevents apoptosis of myocytes by induction of Bcl-x(L) via a Smad1 pathway and might be a novel survival factor without any hypertrophic effect on myocytes.

Animals↗

PubMed2001

Molecular typing and epidemiological study of Salmonella enterica serotype Typhimurium isolates from cattle by fluorescent amplified-fragment length polymorphism fingerprinting and pulsed-field gel electrophoresis.

One hundred twenty Salmonella enterica serotype Typhimurium strains, including 103 isolates from cattle gathered between 1977 and 1999 in the prefecture located on the northern-most island of Japan, were analyzed by using fluorescent amplified-fragment length polymorphism (FAFLP) and pulsed-field gel electrophoresis (PFGE) to examine the genotypic basis of the epidemic. Among these strains, there were 17 FAFLP profiles that formed four distinct clusters (A, B, C, and D). Isolates that belonged to cluster A have become increasingly common since 1992 with the increase of bovine salmonellosis caused by serotype Typhimurium. PFGE resolved 25 banding patterns that formed three distinct clusters (I, II, and III). All the isolates that belonged to FAFLP cluster A, in which all the strains of definitive phage type 104 examined were included, were grouped into PFGE cluster I. Taken together, these results indicate that clonal exchange of serotype Typhimurium has taken place since 1992, and they show a remarkable degree of homogeneity at a molecular level among contemporary isolates from cattle in this region. Moreover, we have sequenced two kinds of FAFLP markers, 142-bp and 132-bp fragments, which were identified as a polymorphic marker of strains that belonged to clusters A and C, respectively. The sequence of the 142-bp fragment shows homology with a segment of P22 phage, and that of the 132-bp fragment shows homology with a segment of traG, which is an F plasmid conjugation gene. FAFLP is apparently as well suited for epidemiological typing of serotype Typhimurium as is PFGE, and FAFLP can provide a source of molecular markers useful for studies of genetic variation in natural populations of serotype Typhimurium.

Animals↗

PubMed2001

Isolation of Encephalitozoon cuniculi using primary tissue culture techniques from a rabbit in a colony showing encephalitozoonosis.

Encephalitozoon spores were isolated in a primary tissue culture of the kidneys from an encephalitozoonosis-suspected rabbit in a municipal zoo in Hokkaido. The isolated spores were morphologically characteristic of microsporidial ones in chromotrope stain, and proven to be E. cuniculi by a polymerase chain reaction (PCR) with a species-specific primer set and by direct DNA sequencing of the PCR products.

Animals↗

PubMed2001

Impact of pre-stent plaque debulking for chronic coronary total occlusions on restenosis reduction.

BACKGROUND: While stenting improves the long-term angiographic outcomes of successfully recanalized chronic coronary total occlusions (CTO), the restenosis rate still remains high. The massive plaque burden in CTO is considered to be one of the causes of in-stent restenosis. METHODS: We examined the pre-stent plaque debulking strategy with high-speed rotational atherectomy (RA) for 50 CTO (Thrombolysis in Myocardial Infarction flow grade 0; estimated occlusive duration, 3 months). Angiographic follow-up results were compared to those of 120 consecutive CTO recanalized with primary stenting in which RA could be indicated retrospectively. Angiographic restenosis was defined as diameter stenosis > 50% at 6-month follow-up. RESULTS: RA could be performed safely in all lesions without any major complications. Adjunctive ballooning and stenting could be performed without high-pressure dilatation (8.4 +/- 1.7 atmospheres). Follow-up angiography was performed in 48 lesions 184 +/- 61 days after the procedure. There were no significant differences in baseline characteristics between the two groups; however, the implanted stent type was different. Quantitative coronary angiography revealed that diameter stenosis was smaller at follow-up (36.2 +/- 20.0% versus 52.2 +/- 26.7%; p = 0.0003) as well as post-procedure (7.8 +/- 11.5% versus 17.8 +/- 13.6%; p < 0.0001) compared with the control group. Angiographic restenosis was also significantly reduced (29.2% versus 52.5%; p = 0.0061). CONCLUSIONS: RA is a safe procedure for plaque debulking of CTO in selected cases. Plaque debulking of CTO facilitates subsequent stent expansion and may reduce the restenosis rate.

Atherectomy, Coronary↗

PubMed2001

Inflammatory cytokines and antigen-responsive mononuclear cells in peripheral blood of cattle infected with Salmonella takoradi.

To determine the immunological response in lactating dairy cows infected with Salmonella (S.) Takoradi, the relationships among distributions of peripheral blood mononuclear cell (PBMC) subpopulations, endotoxin concentrations and dynamics of inflammatory cytokines in blood were investigated. The ratio of CD4+ T cells to CD8+ T cells was significantly lower in the affected cattle than in the control cattle (p<0.05) to decrease in the number of CD4+ T cells in the infected cattle. In contrast, the numbers of gammadeltaT cells, MHC class II-positive cells were significantly higher in the affected cattle than in the control cattle (p<0.01 respectively). Endotoxemia was found in all but one of the affected cattle. Serum IL-1 and IL-6 bioactivities were significantly higher in the affected cattle than in the control cattle (IL-1, p<0.05; IL-6. p<0.01). Serum TNF-alpha activities and levels were not detected in the control and affected cattle. The activities of proinflammatory cytokines determined by the bioassay are important to the relationships between concentration of endotoxin, cytokines and clinical signs. such as leukocytosis, leukopenia, fever or bacterial shedding. Serum IL-2 levels were lower in the affected cattle than in the control cattle. Serum IFN-y was not detected in the affected cattle except one. These results by the ELISA seemed to reflect the condition of subpopulation in the PBMCs from the shedding cattle. The present results suggest that cellular immunity is suppressed while the humoral immunity is activated in acute bovine salmonellosis.

Animals↗

PubMed2000

Activation of prostacyclin synthesis by mechanical stimulation in the ciliated protozoan Tetrahymena thermophila.

We detected a HPLC peak corresponding to 6-keto-PGF(1alpha), a stable metabolite of prostacyclin (PGI(2)), in [1-(14)C]arachidonate metabolites from the ciliated protozoan Tetrahymena thermophila. Quantitative analysis of 6-keto-PGF(1alpha) by enzyme immunoassay revealed that the synthesis and release were rapidly activated by the mechanical stimulation of a short centrifugation. The activation was suppressed significantly by a cyclooxygenase inhibitor, ibuprofen, and was independent of the extracellular Ca(2+). External addition of PGI(2) and its stable analogue, beraprost, caused a transient increase in the tumbling frequency of swimming. Other prostanoids, PGE(2) and PGF(2alpha), have no effect on the swimming. These results indicate that a free-living ciliate, T. thermophila, synthesizes and has a specific sensitivity to PGI(2).

6-Ketoprostaglandin F1 alpha↗

PubMed2000

Prostaglandin I(2), a possible thermo-sensory mediator in Paramecium.

Thermo-sensory mechanisms are little understood. The protozoan, Paramecium multimicronucleatum, is sensitive and responsive to a cooling stimulus. We found that inhibitors of prostaglandin (PG) biosynthesis reduced the response to the cooling stimulus. Inversely, the response suppressed by the inhibitors was recovered by application of stable PGI(2) analogs, including iloprost. Paramecium cells showed binding activity specific for [(3)H]iloprost. Moreover, an arachidonic acid metabolite, possibly PGI(2), was rapidly increased in response to the cooling stimulus, suggesting that prostaglandin biosynthesis plays a crucial role in the cooling-sensory transduction. Paramecium may be a useful model for the investigation of the molecular basis of thermo-sensory mechanisms.

Animals↗

PubMed2000

Percutaneous myocardial ablation in double-chamber right ventricle.

Double-chamber right ventricle (DCRV) exhibits intracavitary outflow obstruction. We report the first case of percutaneous myocardial ablation of DCRV in a 73-year-old patient. An alcohol-induced conus branch occlusion provided the reduction of pressure gradient from 81 to 48 mm Hg and clinical improvement. This strategy may be an alternative therapy to surgery in the adult patients with DCRV. Cathet. Cardiovasc. Intervent. 49:97-101, 2000.

Aged↗

PubMed2000

Effect of a 60 Hz magnetic field on the behavior of Paramecium.

Paramecium multimicronucleatum was used as a model cell to study the effects of 60 Hz magnetic fields on swimming behavior. When exposed to a vertical field of 0.6 T, the cells accumulated at the upper end of the cuvette. An analysis of the swimming behavior revealed that the exposure to the field increased the number of cells swimming upwards maximally at 1 min after onset of the exposure. This effect of the magnetic field was transient, disappearing within a few minutes during the exposure. It is suggested that the magnetic field may amplify to a large extent the negative gravitaxis of Paramecium. Effects of an induced electric field on the swimming behavior are also discussed.

Animals↗

PubMed2000

Differentiation of rat thymic myoid progenitor cell line established by coculture with human T-lymphotropic virus type-I producing human T cells.

A thymus-derived myoid precursor cell line (ST1), which differentiates to myoid cells in the growth arrest condition, was established by the cocultivation of F344 rat thymic cells with human T-lymphotropic virus type-I (HTLV-I)-producing human lymphoid cells. No integration of HTLV-I was detected in ST1 cells by Southern blot hybridization. In a differentiation culture condition such as confluent culture or serum starvation, ST1 cells began to fuse, creating multinuclear giant cells, with the induced expression of MyoD1 and various muscle-specific antigens, including alpha-sarcomeric actin, skeletal muscle myosin, myoglobin, desmin, and acetylcholine receptor. Ultrastructural investigation revealed that differentiated ST1B cells created aggregates of thick and thin filaments with Z-band-like composition, then formed sarcomeric structures and tubular honeycomb arrays. Finally, these cells spontaneously contracted with a frequency of 0.5-2.0 Hz and synchronized with adjoining cells. Transplantation of ST1B cells into nude mice produced a small tumor nodule, showing clear differentiation to skeletal muscle cells. ST1B cells did not indicate any colony-forming activities in soft agar, demonstrating that ST1B cells retain some of the physiologically normal phenotypes. This rare cell line is promising for use in various physiological and pathological investigations including functional research of thymic myoid cells and the pathological role in autoimmune diseases, as well as animal model experiments of cell therapy related to muscular degenerative disorders or regeneration of injured muscles.

Animals↗

PubMed1999

Simple fluctuation of Ca2+ elicits the complex circadian dynamics of cyclic AMP and cyclic GMP in Paramecium.

The circadian dynamics of cyclic adenosine 3',5'-monophosphate (cAMP) and cyclic guanosine 3',5'-monophosphate (cGMP) were simulated in Paramecium multimicronucleatum. The mathematical functions determined closely mimic the Ca2+ dependence of adenylate cyclase (AC) and guanylate cyclase (GC) activities as documented in P. tetraurelia. Patterns of cAMP concentration ([cAMP]), cGMP concentration ([cGMP ]), and the ratio [cGMP]/[cAMP] were calculated with respect to Ca2+ concentrations ([Ca2+]) fluctuating sinusoidally with a period of 24 hours at three different levels: low, medium, and high. The functions displayed varying patterns of [cAMP] characteristic for [Ca2+] fluctuating at each level, while patterns of [cGMP] and [cGMP]/[cAMP] almost paralleled [Ca2+] fluctuations. Similar patterns were observed for actual [cAMP] and [cGMP] measured during the light/dark cycle in P. multimicronucleatum, grown in axenic media additionally containing [Ca2+] at 25 (low), 100 (medium), or 400 (high) microM, respectively. The coincidence between simulated and measured fluctuations of [cAMP] and [cGMP] suggests that the circadian fluctuations of intracellular [Ca2+] primarily stimulate activities of AC and GC via their different degrees of Ca2+ dependence, which are ultimately responsible for the circadian spatiotemporal organization of various physiological functions in Paramecium.

Adenylyl Cyclases↗

PubMed1998

Cooling sensitive [Ca2+]i response associated with signaling of G protein-coupled receptors.

The influence of cooling on the intracellular concentration of Ca2+ ([Ca2+]i) was tested in cell lines expressing chemical receptors. First, when ATP was externally added to rat basophilic leukemia (RBL-2H3) cells, cooling from 37 degrees C to 27 degrees C induced a transient rapid increase in [Ca2+]i. In the absence of extracellular Ca2+, the [Ca2+]i response was induced whereas an inhibitor of microsomal Ca2+ ATPase, thapsigargin, largely abolished the [Ca2+]i response, suggesting that the internal Ca2+ store liberate the Ca2+. A purinergic receptor antagonist, suramin, completely inhibited the [Ca2+]i response to the cooling. Secondly, when serotonin (5-HT) was added to rat glioma C6BU-1 cells, the cooling induced a transient increase in [Ca2+]. This [Ca2+]i response was induced in the absence of external Ca2+, suggesting that the internal Ca2+ stores liberate the Ca2+. These results raise the possibility that some G protein-coupled receptors are sensitive to cooling in the presence of agonist for the receptor.

Adenosine Triphosphate↗

PubMed1998

Chromosome analysis in human oocytes remaining unfertilized after in-vitro insemination: effect of maternal age and fertilization rate.

The incidence of chromosomal abnormalities was studied in 719 unfertilized human oocytes obtained from our in-vitro fertilization (IVF) programme. To make chromosome preparations, a gradual fixation/air-drying method was utilized. Of 388 oocytes successfully karyotyped, 70 (18.0%) were abnormal. The abnormalities included 33 aneuploidies (8.5%) (14 hyperhaploidies and 19 hypohaploidies), 25 diploidies (6.4%) and 15 structural abnormalities (3.9%), three of them being accompanied by aneuploidy. Of the 33 aneuploidies, 16 (48.5%) showed the loss or gain of dyads (so-called non-disjunction), while 17 (51.5%) showed the loss or gain of monads (so-called predivision). There was no maternal age-dependent increase in the incidence of aneuploidy. Unfertilized oocytes from patients with a high fertilization rate (>25%) had a significantly higher (11.4%, P < 0.05) incidence of diploidy compared with the oocytes from the remaining patients (4.3 and 4.0%), suggesting that diploid oocytes might have a lower fertilizing ability.

Adult↗

PubMed1998

Churg-Strauss syndrome diagnosed and followed with gastrointestinal fiberscopic studies and electroneuromyography.

Churg-Strauss syndrome (CSS) is a disorder characterized by hypereosinophilia and systematic vasculitis occurring in individuals with bronchial asthma. We present a case of 24-year-old woman with CSS diagnosed by and followed with gastrointestinal fiberscopic examination and electroneuromyography. The duodenal biopsy showed granulomatous angiitis with eosinophilic infiltration, and the electroneuromyography showed peripheral nerve dysfunction. After steroid treatment, the duodenal erosion and ulcer were almost completely resolved. There was no improvement in electroneuromyography, but the patient was able to walk independently after intensive rehabilitative training.

Adult↗

PubMed1998

[Mediastinal neurilemmoma originating in the right phrenic nerve: a case report].

We report on a 31-year-old man with a mediastinal neurilemmoma originating in the right phrenic nerve. The patient was admitted because of abnormal chest X-ray shadows observed during a routine checkup. A preoperative diagnosis of bronchial cyst in the mediastinum was made. The tumor was resected by video-assisted thoracic surgery. It was 3 x 4 x 3 cm in size, weighted 15 g, and originated in the right phrenic nerve. The histopathologic diagnosis was mediastinal neurilemmoma. Only 14 cases have been reported in the Japanese literature.

Adult↗