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Biomedical subjects

N Murai

Publications and source records attributed to N Murai.

At least 37 records · Page 2Linked to original sources

Post-parturition infectious endocarditis in a patient with a normal mitral valve.

A 29-year-old woman with no history of heart disease was admitted for the treatment of congestive heart failure. Six months earlier, she had given birth, then 20 days later developed a fever and cardiac failure ensued. An echocardiogram demonstrated severe mitral valve regurgitation. Her blood cultures were positive, and we made a diagnosis of mitral valve regurgitation due to infectious endocarditis. Despite treatment for congestive heart failure and antibiotic therapy, resulting in negative blood cultures, her congestive heart failure did not improve, and vegetation on the mitral valve was observed by echocardiography. We successfully removed the infected tissue with mitral valve plasty.

Adult↗

Immediate increase of portal pressure, reflecting sinusoidal shear stress, induced liver regeneration after partial hepatectomy.

The mechanisms whereby hepatocytes in the normal liver can be primed for replication following partial hepatectomy (PHx) are poorly understood. To determine whether "shear stress," which is induced by acute portal hypertension after PHx, is involved in liver regeneration, we studied liver regeneration in rats with splenic transposition (SPT) in which we can minimize the postoperative elevation of portal pressure. Rats underwent 70% PHx following splenic transposition or sham surgery and were killed at various time points to measure portal pressure and other factors. In the control groups, the portal pressure was significantly increased immediately after surgery, peaking at 48 h, and returning to near the preoperative levels by 168 h after PHx. In the SPT group, although portal pressure increased immediately, it decreased to the control levels 6 h after PHx and thereafter repeatedly increased. Tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) levels peaked at 24 and 6 h after PHx, respectively. Proliferative cell analysis was done using MIB-5 antibody, and there were no significant differences between the two groups. Furthermore, liver weight was restored in the same way in both groups. Taken together, the results suggest that an immediate increase in portal pressure is necessary for the initiation of liver regeneration.

Animals↗

Impaired extrapyramidal function caused by the targeted disruption of retinoid X receptor RXRgamma1 isoform.

BACKGROUND: Retinoid X receptors RXRalpha, beta and gamma exert multiple functions in the genetic regulation of mammalian signalling systems by forming heterodimeric complexes with several nuclear ligand receptors. In contrast to the widespread expression of RXRalpha and RXRbeta, the expression of RXRgamma is restricted to particular tissues in which RXRgamma1 is the major isoform expressed in the mouse corpus striatum. RESULTS: To investigate the function of this particular isoform RXRgamma1, we generated RXRgamma1 gene-knockout mice by homologous recombination in ES cells. Both heterozygous and homozygous mice showed severe runting after birth, which often resulted in the early death of mice of the 129/C57BL-6 genetic background. Independent of genetic background, however, the expression of choline acetyltransferase (ChAT) in the cholinergic interneurones in the striatum (caudal putamen) was markedly reduced in the RXRgamma1 gene-null mice. Furthermore, the mutant exhibited an altered response to the administration of dopamine receptor antagonists, haloperidol and chlorpromazine, which normally induce catalepsy in mice. CONCLUSIONS: These results strongly suggest that RXRgamma1 plays an important role in either the development or activation of cholinergic neurones in nigrostriatal extrapyramidal pathways.

Animals↗

[Mapping-guided focal cryoablation and endoaneurysmorrhaphy for a case of ischemic ventricular tachycardia with left ventricular aneurysm].

A 74-year-old woman admitted with exertional dyspnea. Echocardiography revealed the giant left ventricular aneurysm. In the hospital course, she fell into sustained monomorphic ventricular tachycardia. Coronary angiogram showed complete obstruction of the LAD. Left ventricular ejection fraction was 20%. The origin of tachycardia seems to be at infero-apicallateral area of LV by electrophysiology study. Because of the failure of RF energy ablation, we planned mapping-guided cryoablation, CABG and endoaneurysmorrhaphy. To prevent air embolism and myocardial ischemic damage for long aortic cross clamp, intraoperative endocardial mapping was carried out on beating heart due to continuous normothermic coronary blood perfusion (300 ml/min) from the aortic root cannula under aortic clamping. Cold crystalloid cardioplegia changed into the root cannula after EPS, focal cryoablation (-100 degrees C) was performed 3 times on cardiac arrest. Sustained VT was not inducible in the following study. CABG and endoaneurysmorrhaphy was performed on repeated cardiac arrest during single aortic clamp. Postoperative course was uneventful, and she discharged 8 weeks after the operation.

Aged↗

[Aortic valve operations through an upper partial sternotomy].

The median sternotomy has been accepted as the most common approach to the heart, because this approach is easily opened and closed, and easy access to the entire heart is possible. Following the pioneering work by Cosgrove and colleagues of using a parasternal incision for aortic and mitral valve operations, several reports suggested that modified minimal access procedures are likely to be associated with reduced postoperative discomfort and faster recovery. Since July 1997, we have used an upper partial sternotomy and a limited skin incision for isolated aortic valve replacement (AVR) at our hospital. To demonstrate the benefits of this approach, we compared 14 AVR operations using our minimal access incision (group M) with 19 patients undergoing isolated AVR using a conventional sternotomy (group F). In the minimal access group of patients, a small skin incision was made from the second intercostal space to the fourth rib. The pectralis major and intercostal muscle was freed from the sternum, and then a transverse half sternotomy was made in the fourth intercostal space using a striker without injury to the right internal mammary artery. A median partial sternotomy from the supersternal notch to the level of the fourth intercostal space. Cardiopulmonary bypass was connected through the same access site to avoid cannulation of both groins. Conversion to median sternotomy was not necessary in any patient including reexploration for postoperative bleeding. There was no operative mortality, stroke, aortic dissection and perivalvular leaks due to technical factors. In group F, wound infection occurred in 1 patient. One patient in group M required reoperation to control postoperative bleeding. Although mean duration of operation, cardiopulmonary bypass, and cross clamp time in group M was not prolonged, the initiation of cardiopulmonary bypass and aortic crossclamp was delayed by difficulties of cannulations. The distance between the transverse sternotomy (lower edge of divided sternum) and the midpoint of aortic valve annulus was correlated with mean duration of cardiopulmonary bypass and cross clamp time. Our experience demonstrates that isolated AVR through an upper partial sternotomy allows the same quality operations as the full sternotomy, although more clinical experience is required to clarify the benefits of this approach. Excellent exposure of the aortic valve through a partial sternotomy may be attained, if an adequate approach can be selected by the position of aortic valve.

Aortic Valve↗

[Double chambered right ventricle in a 62-year-old female: a surgical case report].

A 62-year-old female was admitted with a chief complaint of transient syncope on exertion. Angiography in right ventricle revealed a defect caused by an anomalous muscle bundle and a pressure gradient of 151 mmHg was observed between the two chambers by cardiac catheterization. Resection of the anomalouse muscle bundle was undertaken using a lower median sternotomy starting at the 2nd intercostal space level and through the outflow tract right ventriculotomy. Patch plasty was also undertaken in the outflow tract. Post-operative course was uneventful and pressure gradient had disappeared at the post-operative catheterization. A rare case of DCRV in a 62-year-old patient with a pressure gradient of 151 mmHg in the right ventricle was reported.

Cardiac Surgical Procedures↗

Genetic and immunological analyses of Vls (VMP-like sequences) of Borrelia burgdorferi.

DNA fragments containing the VMP-like sequence (Vls) were cloned from Borrelia burgdorferi strain 297. Analyses by PCR, PFGE, and Southern hybridization revealed that the Vls sequences existed in multi-copies on the 20-kb borrelial plasmid, but not on chromosomes or other plasmids. One Vls unit of the strain 297 was about 669 bases, and predicted peptides length was 223 amino acids. Homologues of the Vls fragment were detected in three B. burgdorferi strains, a B. garinii strain 20047, and a B. afzelii strain P/Gau. A recombinant VlsII protein prepared in Escherichia coli strain JM109 reacted with antibodies that existed in three of five patients, by immunoblotting. These results suggested that the Vls of B. burgdorferi is expressed in Lyme disease patients.

Amino Acid Sequence↗

Sex differences in facial skin temperature when exposed to darkness with and without warning.

The changes in skin temperature under anxiety were investigated by noninvasive measurements. The nasal skin temperature of 20 subjects was assessed by thermography. The measurement of the skin temperature by thermistor causes stress in subjects. The primary advantages of a thermography over use of a thermistor are noninvasive and accurate. Each subject was made anxious under the 2 conditions of sudden darkness (Sudden darkness condition) or experienced darkness (Experienced darkness condition). Under former, after a baseline facial skin temperature was established, the room light was suddenly turned off. The subject remained seated in darkness for 2 min. The time-series changes were significant for women, but not for men. For women, skin temperature significantly declined in sudden darkness. Experiments on experienced darkness were performed a week later. After a baseline facial skin temperature was established, the subject was told; "The room light would be turned off from now on, but please remain seated without moving". After the instruction, the room light was turned off. The subject remained seated in darkness for 2 min. The resultant time-series changes in skin temperatures were significant in neither men nor women.

Adult↗

[A case report of mitral valve replacement using a parasternal incision (minimally invasive cardiac surgery) with pleuritis tuberculosa and after esophagus operation].

A 68-year-old man underwent mitral valve replacement because of mitral regurgitation (prolaps of anterior mitral leaflet) using parasternal incision (Delos M. Cosgrove, minimally invasive surgery). He had been treated as pulmonary tuberculosis previously and had undergone esophagus operation using stomach role reconstruction beneath the sternum four years before the mitral valve procedure. We could not select median-sternotomy as an approach due to stomach role beneath the sternum, nor left posterolateral thoracotomy because of the heavy left-side pleural adhesion. Cardio-pulmonary bypass cannulations were performed through the same incision, because severe atherosclerosis was found at the distal arteries of the abdominal aorta.

Aged↗

[Left subclavian artery approach for insertion of IABP].

A 62-year-old man admitted with a complication of chest pain. Cardiac catheterization showed three vessel disease with ventricular dysfunction (EF 40%). And aortagram showed that he had arteriosclerosis obliterans (ASO). While he was waiting for operation, the frequency of chest pain increased. It was considered necessary for him to have IABP catheter inserted. We chose left subclavian artery as an access for the insertion of IABP catheter. The catheter was easily introduced into the descending aorta under the fluoroscopy. Emergency CABG was performed the day after insertion of IABP catheter. IABP removed the next morning of operation. Operation and postoperation course was uneventful. In this case, the insertion and the removal were possible under local anesthesia. Left subclavian approach was useful for emergency case with ASO.

Angina, Unstable↗

[Re-do surgery with minimally invasive cardiac surgery (MICS): mitral valve replacement 6 years after open mitral commissurotomy].

A 60-year-old man, who had undergone open mitral commissurotomy 6 years ago, underwent re-do surgery (mitral valve replacement) with minimally invasive cardiac surgery (MICS), using lower partial sternotomy to the height of the right side second intercostal space. Cannulation of the heart was carried out placing a cannula directly into the superior vena cava and a second cannula in the inferior vena cava via the right atrium. Arterial return was through the ascending aorta. Cardioplegia was administered directly into the ascending aorta with intermittent perfusion. Valve replacement was performed by opening directly right side left atrium.

Cardiac Surgical Procedures↗

[Organ failure during the perioperative period: pathophysiology and strategy].

After the establishment of the theoretical and clinical background of SIRS, the mechanism of organ failure induction during the perioperative period was gradually clarified. The deterioration of the mutual regulation of cytokines after surgical stress is considered to be a major cause of organ failure. Hypercytokinemia is one of the pathophysiological features after surgical stress, and thus a new therapeutic approach ameliorating the impaired cytokine network has been applied instead of direct targeting therapy for impaired organs. Organ failure can be anticipated based on a precise assessment of the severity of SIRS or CARS. For example, to prevent postsurgical hepatic failure it is important to minimize surgical stress by assessing the preoperative liver reserve capacity. Excessive surgical stress coupled with underestimation of liver function may result in primary multiple organ failure (MOF) after hepatic surgery. Secondary MOF after postsurgical infection may implicate the bacterial translocation mechanism. At present, only CHDF is considered to be a promising therapy for hypercytokinemia. Therefore the prophylactic approach cannot be neglected. The monitoring of cytokines such as IL-6 during the perioperative period provides valuable information for the prediction of organ failure.

Cytokines↗

[Thoracoabdominal aortic repair without using assisted bypass].

A 41-year-old man, who had undergone descending aortic repair following rupture of the DeBakey type III aortic dissection, underwent thoracoabdominal aneurysm repair 1 year after the first surgery. The operation was performed by partial-clamping and single crossclamping without using assisted bypass or shunt, in order to minimize bleeding ensuing the re-thoracotomy and dissection between lung and the graft.

Adult↗

Identification of p34cdc2 kinase from sea urchin Hemicentrotus pulcherrimus and its involvement in the phosphorylation of myosin II regulatory light chain in the metaphase extract.

We present here the nucleotide sequence for a cDNA clone encoding p34cdc2 from sea urchin, Hemicentrotus pulcherrimus. The obtained cDNA comprised 301 amino acid residues that contained the PSTAIRE domain to be important for binding to cyclins. Amino acid sequence similarity between this clone and other eukaryotic cdc2 sequences averaged approximately 72%. Using p13suc1-conjugated Sepharose 4B and a selective inhibitor of p34cdc2 kinase, butyrolactone I, it was first suggested that p34cdc2 kinase is involved in the phosphorylation of MRLC at both MLCK site and two PKC sites.

Amino Acid Sequence↗

ATP-, K+-dependent heptamer exchange reaction produces hybrids between GroEL and chaperonin from Thermus thermophilus.

Chaperonin from Thermus thermophilus (Tcpn6014.Tcpn107) splits at the plane between two Tcpn607 rings into two parts in a solution containing ATP and K+ (Ishii, N., Taguchi, H., Sasabe, H., and Yoshida, M. (1995) FEBS Lett. 362, 121-125). When Escherichia coli GroEL14 was additionally included in the solution described above, hybrid chaperonins GroEL7.Tcpn607 and GroEL7. Tcpn607.Tcpn107 were formed rapidly (<20 s) at 37 degrees C. The hybrid was also formed from Tcpn6014 and GroEL14 but not from a mutant GroEL14 lacking ATPase activity. The hybrid formation was saturated at approximately 300 microM ATP and approximately 300 mM K+. These results imply that GroEL14 also splits and undergoes a heptamer exchange reaction with Thermus chaperonin under nearly physiological conditions. Similar to parent chaperonins, the isolated hybrid chaperonins exhibited ATPase activity that was susceptible to inhibition by Tcpn107 or GroES7 and mediated folding of other proteins. Once formed, the hybrid chaperonins were stable, and the parent chaperonins were not regenerated from the isolated hybrids under the same conditions in which the hybrids had been formed. Only under conditions in which GroEL in the hybrids was selectively destroyed, such as incubation at 70 degrees C, Thermus chaperonin, but not GroEL14, was regenerated from the hybrid. Therefore, the split reaction may not be an obligatory event repeated in each turnover of the chaperonin functional cycles but an event that occurs only when chaperonin is first exposed to ATP/K+.

3-Isopropylmalate Dehydrogenase↗

Identification of MAPKAPK homolog (MAPKAPK-4) as a myosin II regulatory light-chain kinase in sea urchin egg extracts.

We identified and cloned a homolog of mammalian mitogen-activated protein kinase-activated protein kinase (MAPKAPK)-2 and -3 from sea urchin, Hemicentrotus pulcherrimus. The obtained cDNA clone was composed of 350 amino acid residues which contain MAPK phosphorylation sites and the bipartite nuclear localization signal sites in its C-terminal domain. The clone showed 65.4 and 66.7% amino acid residue identity to human MAPKAPK-2 and -3, respectively. Phylogenetic analysis revealed that the homolog can be classified into a distinct group of MAPKAPK and, therefore, the identified homolog was designated as MAPKAPK-4. Biochemical characterization was performed using recombinant glutathione S-transferase (GST)-MAPKAPK-4 fusion protein. The protein kinase activity of GST-MAPKAPK-4 was activated by MAPK and this enabled the kinase to phosphorylate both glycogen synthase N-terminal peptide and the regulatory light chain of myosin II in vitro. Northern blot analysis showed that MAPKAPK-4 was expressed throughout the development of sea urchin embryos. These observations suggest that MAPKAPK-4 may play an important role in the regulation of myosin II activity during the development of sea urchin.

Amino Acid Sequence↗

Neurotoxicity testing of a new bioactive bone cement.

Bioactive bone cement (BABC) is a novel artificial bone cement. It has some noteworthy characteristics that are applicable to neurological surgery. The toxicity of BABC to the nervous system was tested by implanting BABC and polymethylmethacrylate (PMMA) cement as a control at the parietal and the suboccipital regions of the skull in beagles. The auditory brainstem response (ABR) was tested before and after implantation. Sections of the cerebral cortex and the acoustic nerve were examined at 3 and 6 months after implantation. No abnormal ABR was found in any animals. Histological examination of the cerebral cortex and acoustic nerve demonstrated slight gliosis in both the BABC and PMMA cement groups, but no other abnormalities.

Animals↗

[Surgical treatment of malignant hemangioendothelioma originated from the right atrium: a case report].

A 32-year-old man was admitted to our hospital because a cardiac tumor had been pointed out by a physician. CT scans showed a mass lesion with irregular patterns in the right atrium. The patient had the diagnosis of a malignant cardiac or pericardial tumor and an operation was performed. The mass originated from the right atrium included massive coagulated blood, and was resected with the pericardium and the right pleura. The histological diagnosis was malignant hemangioendothelioma. We present this case because only 35 patients with cardiac malignant hemangioendothelioma were reported in Japan.

Adult↗