Biomedical subjects

Y Fukada

Publications and source records attributed to Y Fukada.

At least 19 recordsLinked to original sources

PubMed2005

[Overlapping ventriculoplasty for ischemic cardiomyopathy].

We have previously reported overlapping cardiac volume reduction operation (OLCVR) for dilated cardiomyopathy. Because of the acceptable clinical outcome and especially the excellent ellipsoidal shape of the left ventricle (LV) after surgery, we extended this indication for ischemic cardiomyopathy (ICM) with dilated LV. In such cases we combined OLCVR with mitral annuloplasty and papillary muscles approximation (PMA), called integrated overlapping ventriculoplasty (IOLVP). From March 2003 to July 2004, we performed IOLVP with coronary artery bypass grafting (CABG) for 8 patients who were diagnosed ICM. There is no operative mortality. Pre- and postoperative hemodynamics data are follows: LV ejection fraction (LVEF) improved from 22.4 +/- 11.9 to 33.4 +/- 10.5%, LV end-diastolic volume index (LVEDVI) decreased from 155.5 +/- 26.5 to 93.7 +/- 13.5 ml/m2 and LV end-diastolic diameter (LVDd) diminished from 66.0 +/- 8.9 to 60.5 +/- 8.4mm. Mitral regurgitation changed from 2.6 +/- 0.8 to 0.1 +/- 0.2 degree. New York Heart Association (NYHA) functional class improved from 3.3 +/- 0.5 to 1.3 +/- 0.5. LV shape became ellipsoidal without akinesis lesion. IOLVP is considered as a good option for ICM with dilated left ventricle.

Aged↗

PubMed2003

[Surgical treatment to an old patient with right coronary artery aneurysm; report of a case].

The patient was 75-year-old woman. The patient was referred to our hospital for operation due to a developing right coronary artery aneurysm. The coronary artery angiography showed that the aneurysm was 3 cm in diameter which had not existed two years previously, and with a 75% distal stenosis. The operation was made during cardiac arrest. A sapheous vein graft was used to bypass to the distal artery first. Then the aneurysm was resected, and both proximal and distal arteries were ligated. The pacemaker was implanted on the third postoperative day for sick sinus syndrome, the patient got a better recovery. Surgical treatment should be recommended to coronary artery aneurysm, and sapheous vein was a good selection for bypass graft when the diameter of native artery was relatively large.

Aged↗

PubMed2002

Prenatal course and pregnancy outcome of fetuses with a transient nuchal translucency.

OBJECTIVES: This study was designed to correlate fetuses in a normal prenatal population who exhibited transient nuchal translucency (NT) with both prenatal course and pregnancy outcome. METHODS: The fetuses with abnormal NT were followed by ultrasonography at 1-2-week intervals during their prenatal course. Fetuses with NT who exhibited no detectable congenital malformations were defined as the NTO group; fetuses with abnormal NT and structural malformations but no chromosomal abnormalities were placed in the SM group; and fetuses with abnormal NT, structural malformations, and chromosomal abnormalities were categorized as the CA group. The groups were compared by: maternal age, weeks of gestation by ultrasound and the NT value at the initial exam, the maximum NT value, and the duration of abnormal NT. RESULTS: During the study period, 92 fetuses with abnormal NT were found, monochorionic twins excluded. Of the 92 fetuses, 80 were in the NTO group, 10 were in the SM group, and two were in the CA group. The maternal age and the gestational weeks at the initial diagnosis were not significantly different in the NTO and the SM groups. However, the NT value at the initial diagnosis, maximum NT value, and the duration of abnormal NT were significantly greater in the SM group than those values in the NTO group. CONCLUSIONS: Fetuses with transient nuchal translucency commonly had structural malformations, particularly fetuses with significant and large persistent NT.

Adult↗

PubMed2002

[An evaluation of the potential ischemia of the forearm after harvesting of radial artery by near infrared spectroscopy].

We evaluated the potential ischemia of the forearm after harvesting of radial artery (RA) for coronary artery bypass grafting (CABG) by near infrared spectroscopy (NIRS). The subjects consist of two groups; patients group (group P) including 18 patients who received CABG with RA and control group (group C) including 9 healthy volunteers. Group P was divided into two groups; early post operative group (group E, n = 11) and mid-term post operative group (group M, n = 7). NIRS was used to measure the recovery time (RT) in the muscles of the forearm during occlusion test. There was a significant prolongation of the RT in group P than group C. There was no significant difference of the RT between group E and group M. In conclusion, harvesting of RA may cause ischemia of the forearm and it may continue for a long time.

Aged↗

PubMed2001

Chicken pineal Cry genes: light-dependent up-regulation of cCry1 and cCry2 transcripts.

Vertebrate cryptochrome homologs (CRYs) are negative regulators for the transcription/translation-based autoregulatory feedback loop of the circadian clock. In this study we identified two Cry genes in the chicken, cCry1 and cCry2, which are expressed in the pineal gland. Messenger RNA levels of both cCry1 and cCry2 displayed circadian oscillation in cultured pineal cells under light/dark and constant darkness conditions. Noticeably, their mRNA levels during the light period were significantly higher than those in the dark, indicating light-dependent up-regulation of the two Cry genes mediated by photoreceptor(s) intrinsic to the chick pineal cells. These cCRYs inhibited E-box element-dependent cBMAL1/2-cCLOCK-induced transcription, suggesting that the chick pineal circadian oscillator is composed of molecules that are functionally similar to those of mammals but are subject to light-regulation distinct from the mammalian clockwork.

Amino Acid Sequence↗

PubMed2001

Light-induced phase-delay of the chicken pineal circadian clock is associated with the induction of cE4bp4, a potential transcriptional repressor of cPer2 gene.

The chicken pineal gland contains the autonomous circadian oscillator together with the photic-input pathway. We searched for chicken pineal genes that are induced by light in a time-of-day-dependent manner, and isolated chicken homolog of bZIP transcription factor E4bp4 (cE4bp4) showing high similarity to vrille, one of the Drosophila clock genes. cE4bp4 was expressed rhythmically in the pineal gland with a peak at very early (subjective) night under both 12-h light/12-h dark cycle and constant dark conditions, and the phase was nearly opposite to the expression rhythm of cPer2, a chicken pineal clock gene. Luciferase reporter gene assays showed that cE4BP4 represses cPer2 promoter through a E4BP4-recognition sequence present in the 5'-flanking region, indicating that cE4BP4 can down-regulate the chick pineal cPer2 expression. In vivo light-perturbation studies showed that the prolongation of the light period to early subjective night maintained the high level expression of the pineal cE4bp4, and presumably as a consequence delayed the onset of the induction of the pineal cPer2 expression in the next morning. These light-dependent changes in the mRNA levels of the pineal cE4bp4 and cPer2 were followed by a phase-delay of the subsequent cycles of cE4bp4/cPer2 expression, suggesting that cE4BP4 plays an important role in the phase-delaying process as a light-dependent suppressor of cPer2 gene.

Amino Acid Sequence↗

PubMed2001

Photoreception and circadian clock system of the chicken pineal gland.

Chicken pinealocytes contain three major components of the circadian clock system: 1) a self-sustained oscillator, 2) a photic-input pathway to the oscillator, and 3) an overt output represented by the rhythmic production of melatonin. Even under cultured conditions of isolated pineal gland or dissociated pinealocytes, the input-oscillator-output functions are well maintained. Because of these experimental advantages, chicken pineal gland has been one of the best models for the study of the circadian clock system. Since the finding of a pineal-specific photoreceptive molecule, pinopsin, we have characterized the endogenous phototransduction pathway in the pinealocytes. On the other hand, despite the long history of chick pineal research, the molecular mechanism underlying the pineal clock oscillation has been largely unknown. Our recent characterization of the chick pineal clock genes strongly suggests that they constitute a transcription/translation-based autoregulatory feedback loop, which is very similar to that generating circadian rhythmicity in mammalian SCN.

Animals↗

PubMed2001

Cloning of mouse BMAL2 and its daily expression profile in the suprachiasmatic nucleus: a remarkable acceleration of Bmal2 sequence divergence after Bmal gene duplication.

Brain-Muscle-Arnt-Like-protein 2 (BMAL2; Arnt4) (aryl hydrocarbon receptor nuclear translocator) is a recently identified basic Helix-Loop-Helix-Per-Arnt-Sim (bHLH-PAS) transcription factor, which contributes to a positive regulation of autoregulatory feedback loop in vertebrate circadian clock systems. In this study, we cloned cDNAs encoding mouse and rat BMAL2 (mBMAL2 and rBMAL2) from mouse midbrain and rat-1 fibroblast cells, respectively. A phylogenetic analysis strongly suggested that vertebrate Bmal1 and Bmal2 genes were generated by a single gene duplication of an ancestral Bmal gene, a vertebrate ortholog of dCyc gene, and that 'BMAL2's putatively termed so far are orthologous. Interestingly, BMAL2 proteins have diverged about 20-fold more rapidly than BMAL1 proteins after the duplication, suggesting an as-yet-unidentified function conserved in BMAL1 but not in BMAL2. mBmal2 mRNA was constitutively expressed throughout the day under light-dark cycle in the mouse hypothalamus containing suprachiasmatic nucleus, the site of the central circadian oscillator in mammals.

ARNTL Transcription Factors↗

PubMed2001

Circadian and photic regulation of MAP kinase by Ras- and protein phosphatase-dependent pathways in the chick pineal gland.

Chick pineal mitogen-activated protein kinase (MAPK) exhibits circadian activation and light-dependent deactivation at nighttime. Here we report that, in the chick pineal gland, levels of active forms of MAPK, MEK, Raf-1 and Ras exhibited synchronous circadian rhythms with peaks during the subjective night, suggesting a sequential activation of components in the classical Ras-MAPK pathway in a circadian manner. In contrast, the light-dependent deactivation of MAPK was not accompanied by any change of MEK activity, but it was attributed to the light-dependent activation of protein phosphatase dephosphorylating MAPK. These results indicate that the photic and clock signals regulate MAPK activity via independent pathways, and suggest a pivotal role of MAPK in photic entrainment and maintenance of the circadian oscillation.

Animals↗

PubMed2001

Disorder in sequential speech perception: a case study on pure word deafness.

We described disorders of a patient which were uniquely restricted to speech perception of syllable sequences after brain damage. The results of series of experiments using syllable sequences showed "negative recency effect," in which the subject's repetition performance at the latter syllable position was remarkably poor. Experimental analyses suggested that the "negative recency effect" could be due to dual factors: the lower rate of processing of speech sounds and the memory load of holding processes of preceding syllables imposed on the succeeding phonological processing. The results also suggested that the holding processes which imposed the memory load on the succeeding auditory phonological coding processing were modality nonspecific.

Adult↗

PubMed2001

Intracranial electroencephalographic changes in deep anesthesia.

OBJECTIVE: It is well known that electroencephalograms (EEGs) show electrical silence in deep anesthesia as well as brain death. This is the first report on intracranial EEG changes in deep anesthesia. METHODS: We developed a new direct brain monitoring system capable of recording intracranial EEGs. This study included 13 patients with head trauma or cerebrovascular accident under deep anesthesia. RESULTS: The intracranial EEGs showed different patterns of wave activity in depth compared with the cortical surface. In 3 of the cases, the scalp EEG showed a flat tracing at 2.0-2.5% of isoflurane. In two of the cases, the intracranial EEGs showed electrical silence when the scalp EEG was flat. Decreasing the concentration of isoflurane to 1.5%, the intracranial EEG showed single paroxysmal appearance of 'revival' theta waves on the electrocorticogram (ECoG) or electroventriculogram (EVG). The intracranial 'revival' wave was followed by high-voltage burst-waves. In another case, at 2.0-2.5% of isoflurane, the amplitude of the waves was greatest on the EVG. CONCLUSION: There is wave activity difference in the brain depth, which the scalp EEG is unable to show. Intracranial EEGs are able to show the first signs of revival after a nearly flat tracing in deep anesthesia.

Adult↗

PubMed2001

Chicken pineal clock genes: implication of BMAL2 as a bidirectional regulator in circadian clock oscillation.

BACKGROUND: In a transcription/translation-based autoregulatory feedback loop of vertebrate circadian clock systems, a BMAL1-CLOCK heterodimer is a positive regulator for the transcription of the negative element gene Per. The chicken pineal gland represents a photosensitive clock tissue, but the pineal clock genes constituting the oscillator loop have been less well characterized. RESULTS: We identified expression of the Per2, Bmal1, Bmal2 and Clock genes in the chicken pineal gland. Messenger RNA levels of these genes exhibited overt circadian rhythms in the pineal cells, both in vivo and in culture. In vitro functional analyses revealed the formation of cBMAL1-cCLOCK and cBMAL2-cCLOCK heteromers. Both of the cBMAL-cCLOCK heteromers activated E-box element-dependent transcription, which was negatively regulated by cPER2 in luciferase assays. Co-expression of cCLOCK, cBMAL1 and cBMAL2 co-operatively activated E-box element-dependent transcription, and a greater level of expression of cBMAL2 inhibited the activation. In the cultured pineal cells, an over-expression of either cBMAL1 or cBMAL2 disrupted the circadian rhythm of melatonin production. CONCLUSION: The functional characterization of the chicken pineal clock molecules supports the key roles of BMAL1, BMAL2 and CLOCK which contribute to the E-box-dependent transcriptional regulation in the circadian clock system.

ARNTL Transcription Factors↗

PubMed2001

Effect of brefeldin A on melatonin secretion of chick pineal cells.

Melatonin is secreted from the pineal gland in a circadian manner. It is well established that the synthesis of melatonin shows a diurnal rhythm reflecting a daily change in serotonin N-acetyltransferase (NAT) activity, and the overall secretion of melatonin requires a cellular release process, which is poorly understood. To investigate the possible involvement of Golgi-derived vesicles in the release, we examined the effect of brefeldin A (BFA), a reversible inhibitor of Golgi-mediated secretion, on melatonin secretion of cultured chick pineal cells. We show here that treatment with BFA completely disassembles the Golgi apparatus and reduces melatonin secretion. In more detailed time course experiments, however, the inhibition of melatonin secretion is only observed after the removal of BFA in parallel with the reassembly of the Golgi apparatus. This inhibition of melatonin secretion is not accompanied by accumulation of melatonin in the cells. These observations indicate that chick pineal melatonin is released independently of the Golgi-derived vesicles, and suggest inhibition of melatonin synthesis after the removal of BFA. By measuring the activities and mRNA levels of melatonin-synthesizing enzymes, we found that the removal of BFA specifically inhibits NAT activity at the protein level. On the other hand, BFA causes no detectable phase-shift of the chick pineal oscillator regulating the circadian rhythm of melatonin secretion. The results presented here suggest that the Golgi-mediated vesicular transport is involved in neither the melatonin release nor the time-keeping mechanism of the circadian oscillator, but rather contributes to the regulation of NAT activity.

Animals↗

PubMed2001

Regulatory mechanism for the stability of the meta II intermediate of pinopsin.

Pinopsin is a chicken pineal photoreceptive molecule with a possible role in photoentrainment of the circadian clock. Sequence comparison among members of the rhodopsin family has suggested that pinopsin might have properties more similar to cone visual pigments than to rhodopsin, but the lifetime of the physiologically active intermediate (meta II) of pinopsin is rather similar to that of metarhodopsin II, which is far more stable than meta II intermediates of cone visual pigments [Nakamura, A. et al., (1999) Biochemistry 38, 14738-14745]. In the present study, we investigated the amino acid residue(s) contributing to this unique property of pinopsin by using site-directed mutagenesis to pinopsin-specific structural features, (i) Ser171, (ii) Asn184, and (iii) the second extracellular loop two-amino acids shorter than that of cone visual pigments. The meta II stability of the 171/184 double mutant of pinopsin (S171R/N184D) is almost the same as that of wild-type pinopsin. In contrast, the meta II lifetime is markedly shortened (one third) by introduction of the third mutation (replacement of a six-amino acid stretch, 188-193, by the corresponding eight residues of chicken green-sensitive cone pigment) to the 171/184 double mutant of pinopsin. Consistently, meta II of the green-sensitive pigment mutant, in which the eight-amino acid stretch is inversely replaced by the corresponding six residues of pinopsin, is more stable than meta II of the wild-type pigment. These results strongly suggest that the specific sequence and/or the number of residues at amino acids 188-193 in pinopsin play an important role in the stabilization of the meta II intermediate.

Amino Acid Substitution↗

PubMed2001

Rapid detection of chromosome aneuploidies by prenatal interphase FISH (fluorescence in situ hybridization) and its clinical utility in Japan.

OBJECTIVE: The purpose of this study was to assess the accuracy, informative rate, detection rate, and clinical utility of prenatal interphase fluorescence in situ hybridization (FISH) analysis of amniotic fluid samples from Japanese women. METHODS: Amniotic fluid specimens from 2,639 Japanese women were received for prenatal interphase FISH and chromosome analysis. A questionnaire was designed to evaluate FISH clinical utility by collaboration sites. RESULTS: Based on 2,319 tested samples, the accuracy (100%), informative (94%), and detection (87.6%) rates were all high. The accuracy (100%), informative (90.2%), and detection (90.0%) rates were also remarkable in third-trimester pregnancies. We perceive significant advantages from this test regarding medical management and patient satisfaction. CONCLUSIONS: This novel report shows that in Japan prenatal interphase FISH testing is highly informative and accurate, not only in second-trimester pregnancies but also in third-trimester pregnancies. This test provides advantages to both physicians and patients, provided that its capabilities and limitations are understood.

Adult↗

PubMed2001

[Efficacy of radiofrequency catheter ablation in a patient with sinus node reentrant tachycardia].

We performed electrophysiological study and catheter ablation on a 62-year-old patient with supraventricular tachycardia(SVT). This SVT was reproducibly initiated and terminated by atrial stimulation during the electrophysiological testing. The P-wave morphology and atrial activation sequence of intracardiac electrograms were identical to those in normal sinus rhythm. SVT was terminated with carotid sinus massage that increased vagal tone, and for this reason, the reentry circuit of SVT could be localized in sinus node. On the basis of these findings, the SVT was diagnosed as sinus node re-entrant tachycardia and was successfully eliminated by radiofrequency catheter ablation. Radiofrequency catheter ablation would be effective in patients with sinus node reentrant tachycardia refractory to anti-arrhythmic drugs. It should, however, be performed with careful consideration to the influence of the sinus node.

Catheter Ablation↗

PubMed2001

Preoperative disseminated intravascular coagulation associated with aortic aneurysms.

BACKGROUND: To report clinical experiences with disseminated intravascular coagulation (DIC) associated with aortic aneurysms (AA) and discuss therapeutic strategy. METHODS DESIGN AND SETTINGS: uncontrolled, observational study in a university hospital. PATIENTS: among 547 patients with AA treated between 1991 and 1999, 10 patients (7 males, 3 females, mean age 68.5+/-2.5) presenting a preoperative DIC score (defined by the Ministry of Health and Welfare in Japan) of 6 or higher were analyzed. The etiology was dissection for 5 and non-dissection for 5 patients. Six of 10 patients had a bleeding tendency. Eight patients received preoperative anticoagulant therapy. Prosthetic replacement was undertaken for 8 patients except for 2 patients in poor condition. RESULTS: There were no operative deaths in 8 surgical cases. One non-surgical case died of deteriorated bleeding tendency. The mean DIC score was 8.0+/-0.6 at admission, which was reduced to 4.4+/-0.5 at discharge (p<0.05). Prothrombin time, platelet counts, and fibrinogen levels tended to be normalized by the 7th postoperative day. Serum FDP levels decreased with surgery, but tended to increase at the time of discharge and the later follow-up period. Hematologic disturbances and bleeding tendency recurred in 2 patients in the follow-up period. CONCLUSIONS: In the majority of patients presenting DIC with aortic aneurysm, surgical treatment can be performed safely if adequately managed by anticoagulant therapy. Consumptive coagulopathy usually resolved after surgical intervention, but some patients developed DIC in the later period. If DIC recurs, it is essential to search for contributory causes.

Aged↗

PubMed2000

Phototransduction molecules in the pigeon deep brain.

Photoreceptive areas responsible for the regulation of photoperiodicity have been localized in the brain of some avian species. We found that immunoreactivities to rhodopsin and the alpha-subunit of rod-type transducin (Gt(1)alpha) were colocalized in cerebrospinal fluid (CSF) contacting neurons in the pigeon lateral septum, a possible site for photoreception. Furthermore, RT-PCR analyses showed specific gene expression of both cGMP-phosphodiesterase beta-subunit and cone-type cGMP-gated cation channel alpha-subunit in this region. These results suggest that several components in rod/cone photoreceptors compositely contribute to the deep encephalic phototransduction cascade.

3',5'-Cyclic-GMP Phosphodiesterases↗