Biomedical subjects

N Murai

Publications and source records attributed to N Murai.

At least 55 records · Page 3Linked to original sources

PubMed1997

[A case report of type A dissection of the aorta presenting as a superior vena cava syndrome 10 years after aortic valve replacement].

Aortic dissection usually result in chest pain and back pain. This patient is a 58 year-old man who received aortic valve replacement for aortic regurgitation 10 years ago. In this case, the patient had superior vena cava syndrome as a result of a painless aortic dissection. The superior vena cava was compressed by the ascending aorta itself, which had become very large but had not ruptured into the mediastinum. He underwent modified Carbrol's operation under hypothermic cardiopulmonary bypass and circulation arrest on May 8, 1995. Dissecting aneurysm in the late term after aortic valve replacement is rare, and for it to result in superior vena cava syndrome is especially rare.

Aortic Dissection↗

PubMed1997

[Hemorheological effects of autologous blood storage before surgery for cardiac valvular diseases].

The hemorheological effects of autologous blood storage with or without the use of erythropoietin were examined before surgery for valvular disease. There was no rheological difference between patients with aortic (16 cases) or mitral (10 cases) valve disease. Before storage, the levels of hematocrit, whole blood viscosity, and especially coefficient of rheology, were lower (p < 0.05) in the blood stored with erythropoietin, but this difference disappeared after storage. The plasma viscosity of both groups did not change before and after storage. The viscosity of blood was equalized after the storage of blood, irrespective of the use of erythropoietin.

Adult↗

PubMed1997

[A case report of Vp3 hepatocellular carcinoma responding to multidisciplinary treatment].

We report a 60-year-old man who had hepatocellular carcinoma with tumor thrombus in the main portal vein and left portal branch (VP3HCC). He was treated with transarterial chemo-embolization, surgical resection and intra-arterial infusion chemotherapy. He is now surviving without any sign of recurrence for 12 months after the initial therapy, even though the prognosis of VP3HCC is poor. This is a case in which the effect of multidisciplinary treatment was indicated.

Antibiotics, Antineoplastic↗

PubMed1997

[The comparison of tepid and moderate hypothermic cardiopulmonary bypass in cardiac surgery].

Normothermic cardiopulmonary bypass (CPB) is being increasingly used at some institutions. Patients undergoing normothermic CPB have a higher systemic oxygen demand and may be at higher risk for ischemic injury. This study was designed to confirm the clinical efficacy and safety of tepid hypothermic CPB. Thirty-six patients undergoing open heart surgery between June 1993 and August 1994 were divided into two groups: tepid (n = 18, 32 degrees C) and moderate (n = 18, 26 degrees C) hypothermic CPB. There were no significant differences in preoperative and perioperative patients characteristics between the two groups. The mean aortic cross-clamp time did not differ between two groups, but the mean CPB time was significantly shorter in tepid hypothermic patients. Serum lactate after CPB and lactate/pyrvate ratio during CPB in tepid hypothermic patients were significantly lower than in moderate hypothermic patients. The mixed venous oxygen saturation in tepid hypothermic patients was significantly lower however, it was maintained at levels more than 70% during CPB. This study suggests that tepid hypothermic CPB is a safe and effective alternative to moderate hypothermic CPB for patients undergoing open heart surgery. Previous reports have documented that patients undergoing normothermic CPB are at greater risk for cerebral desaturation. We should evaluate cerebral venous oxygen saturation during tepid hypothermic CPB before the induction of normothermic CPB.

Cardiac Surgical Procedures↗

PubMed1996

GroEL locked in a closed conformation by an interdomain cross-link can bind ATP and polypeptide but cannot process further reaction steps.

It has been believed that when GroEL binds to GroES its apical domain moves upward and outward. To inhibit this "opening" movement, its equatorial and apical domains were cross-linked through a disulfide bond between mutationally introduced cysteine residues at the positions of Asp-83 and Lys-327. To avoid possible undesired cross-linking, we at first prepared a mutant GroEL (GroELNC; Cys-138 --> Ser, Cys-458 --> Ser, Cys-519 --> Ser) in which all cysteine residues in wild-type GroEL were replaced by serine residues. GroELNC was fully functional as a chaperonin. We then introduced the above two point mutations into GroELNC to generate a mutant (GroELAEX; Cys-138 --> Ser, Cys-458 --> Ser, Cys-519 --> Ser and Asp-83 --> Cys, Lys-327 --> Cys). Oxidized GroELAEX, which is locked in a "closed" conformation by an interdomain disulfide bond, can bind 6-7 mol of ATP, which remain bound without hydrolysis. This ATP-bound, oxidized GroELAEX can bind the stably nonnative substrate protein isopropylmalate dehydrogenase, whereas the nucleotide-free oxidized GroELAEX binds it with a weaker affinity. However, oxidized GroELAEX fails to process further reaction steps such as ATP hydrolysis, binding of GroES, dissociation of substrate protein from GroEL, and facilitating protein folding. When disulfide bonds in oxidized GroELAEX are reduced, GroELAEX exerts the ability to process all the reactions just as GroELNC and wild-type GroEL. Indications from these results are: hydrolysis of ATP may require opening movement of the apical domain; GroES binds to an open form of GroEL; and substrate polypeptide is released from GroEL coupled with either ATP hydrolysis or opening movement of the apical domain.

3-Isopropylmalate Dehydrogenase↗

PubMed1996

Multichannel optical recording of neuronal network activity and synaptic potentiation in dissociated cultures from rat hippocampus.

The activity of neuronal networks formed by dissociated rat hippocampal neurons was observed with a 128-channel optical recording apparatus using an absorptive voltage-sensitive dye, RH482. Two-dimensional patterns of neural electrical events along somata and neurites in the networks were visualized as the responses to pulse stimuli applied to the somata of the presynaptic neurons by patch-clamp electrodes. Synaptic delay was analyzed from propagation delay of the responses along the neurites. Synaptic potentiation was also observed in postsynaptic responses that were amplified by a factor of 1.24 after tetanization. In contrast, presynaptic components were unaffected by the procedure. In the light of the present results, multichannel optical recording promises to promote our understanding of neuronal interactions at cellular level.

Action Potentials↗

PubMed1996

Vectors carrying two separate T-DNAs for co-transformation of higher plants mediated by Agrobacterium tumefaciens and segregation of transformants free from selection markers.

Novel 'super-binary' vectors that carried two separate T-DNAs were constructed. One T-DNA contained a drug-resistance, selection-marker gene and the other contained a gene for beta-glucuronidase (GUS). A large number of tobacco (Nicotiana tabacum L.) and rice (Oryza sativa L.) transformants were produced by Agrobacterium tumefaciens LBA4404 that carried the vectors. Frequency of co-transformation with the two T-DNAs was greater than 47% GUS-positive, drug-sensitive progeny were obtained from more than half of the co-transformants. Molecular analyses by Southern hybridization and polymerase chain reactions confirmed integration and segregation of the T-DNAs. Thus, the non-selectable T-DNA that was genetically separable from the selection marker was integrated into more than a quarter of the initial, drug-resistant transformants. Since various DNA fragments may be inserted into the non-selectable T-DNA by a simple procedure, these vectors will likely be very useful for the production of marker-free transformants of diverse plant species. Delivery of two T-DNAs to plants from mixtures of A. tumefaciens was also tested, but frequency of co-transformation was relatively low.

Agrobacterium tumefaciens↗

PubMed1996

Midbrain tegmental lesions affecting or sparing the pupillary fibres.

Two patients with oculomotor palsy caused by midbrain infarction are reported. In the first, pupillary reaction was affected and in the second this reaction was spared. Because the lesions in the anterior part of the tegmentum were in the upper midbrain in the first patient and in the lower midbrain in the second, it is suggested that the pupillary components of the oculomotor nerve are located in the upper midbrain.

Aged↗

PubMed1996

Apoptosis of human glioma cells in vitro and in vivo induced by a neutralizing antibody against human basic fibroblast growth factor.

Basic fibroblast growth factor (bFGF) is mitogenic to neuroectoderm- and mesoderm-derived cells and is a potent angiogenic factor. Abundant amounts of this factor and its receptor are detected in human glioma tissues and cells, and bFGF in glioma is thought to be involved in autonomous cell growth as an autocrine growth factor. A neutralizing mouse monoclonal antibody (MAb) against bFGF, 3H3 MAb, has been shown to inhibit both in vitro and in vivo growth of human glioma cell lines. This study shows that the human glioma cell lines U-87MG and U-251MG, which express high levels of bFGF and its receptor, can be induced to undergo apoptosis when cultured with 3H3 MAb. It is also demonstrated that 3H3 MAb can cause apoptosis in the same glioma cells that were transplanted into nude mice. Furthermore, enforced overexpression of bcl-2 protein by gene transfection prevented 3H3 MAb-induced apoptosis of glioma cells. It is concluded that induction of apoptosis by the neutralizing antibody is a promising therapeutic strategy for glioma.

Antibodies↗

PubMed1996

[A surgical case report of angina pectoris with multiple coronary giant aneurysms].

A 47-year-old man with sever angina pectoris was referred for surgery. Preoperative coronary angiogram revealed giant multiple aneurysms of RCA (Seg 1-Seg 3) and LCX (Seg 11) and LAD (Seg 6). Stenoses were found distal to aneurysm, 90% in RCA-Seg 4, CX-Seg 11, 100% in LAD- Seg 6 and DX-Seg 9 and OM-Seg 12, with collaterals from RCA to LAD. Left ventlicle contracted poorly with the EF of 36 due to anteroseptal infarction. Coronary artery bypass grafting were performed to LAD using a LITA, to DX and LCX using a SVG in the sequential fashion. Postoperative coronary cineangiogram demonstrated that all grafts were patent and multiple giant coronary aneurysms resembled coronary arterial changes of Kawasaki's disease.

Angina Pectoris↗

PubMed1996

[Aortic regurgitation due to ruptured fibrous band in the noncoronary cusp: a case report].

A 67-year-old man with aortic regurgitation underwent aortic valve replacement with a 25 mm St. Jude Medical artificial valve. Intraoperative observation found several ruptured fibrous bands between the noncoronary cusp and sino-tubular ridge over the left noncoronary commissure. The same structure was observed at the left cusp, which were not ruptured. The ascending aorta was dilated to about 4 cm in diameter, so was wrapped with an artificial graft to prevent aneurysmal change. Pathological examination revealed chronic valvulitis and degenerative change at the aortic valve, and idiopathic medial degeneration at the aortic wall.

Aged↗

PubMed1995

A novel insertion sequence (IS)-like element of the thermophilic bacterium PS3 promotes expression of the alanine carrier protein-encoding gene.

A novel insertion sequence (IS)-like element was found in the 5'-upstream region of the alanine carrier protein-encoding gene (acp) in the thermophilic bacterium PS3 chromosomal DNA. The sequence contained an open reading frame (ORF) encoding a polypeptide of 369 amino acids which revealed high similarity with ORFs from IS891 from the cyanobacterium Anabaena and IS1136 from Saccharopolyspora erythraea. The direction of transcription was the same as that of acp, and typical inverted and direct repeats characteristic of IS were found in both the 5' and 3' region of the ORF. Southern hybridization analysis of the chromosomal DNA revealed that multiple copies of the ORF sequence were contained in the PS3 genome. This element might well be a member of a new IS family including IS891 and IS1136, and we have designated this element IS1341. The analysis of acp expression in Escherichia coli cells indicated that IS1341 promotes the expression of acp.

Amino Acid Sequence↗

PubMed1995

Kinetic analysis of interactions between GroEL and reduced alpha-lactalbumin. Effect of GroES and nucleotides.

The real-time analysis of the association and dissociation of chaperonin with respect to its substrate protein was carried out using the BIAcore system. We immobilized alpha-lactalbumin (LA) as a substrate protein on the sensor chip and the GroEL solution was passed over it. Whereas GroEL did not bind to the immobilized native LA, it associated with the immobilized Ca(2+)-depleted, disulfide bond-reduced form of LA (rLA) rapidly (kon = 1.96 x 10(5) M-1 S-1) and dissociated extremely slowly (koff = 2.08 x 10(-4) S-1), giving a low dissociation constant (KD = 1.06 nM). MgATP greatly accelerated the dissociation (koff = 0.15 +/- 0.02 S-1). The KD value remained almost unchanged when GroES and/or 10 microM ADP was included in the GroEL solution. However, when 1 mM ADP was included, the KD value of GroEL increased by 2 orders of magnitude solely due to the change in koff. When GroES and 1 mM ADP were included, no interaction with rLA was detected due to changes in both kon and koff. These results indicate that GroEL/ES has high and low affinity ADP binding sites and that occupation of the low affinity sites by ADP was responsible for the loss of ability to interact with the substrate protein. The effect of excess GroES on the preformed GroEL.rLA and GroEL/ES.rLA complexes was also examined. With increasing GroES, the dissociation of GroEL and GroEL/ES from rLA was accelerated, and thus the possibility is suggested that the substrate protein and GroES compete for the same site on GroEL.

Adenine Nucleotides↗

PubMed1995

Temporal coding in the guinea-pig auditory cortex as revealed by optical imaging and its pattern-time-series analysis.

The neural network structure of a guinea-pig's primary auditory cortex is estimated by applying pattern-time-series analysis to the auditory evoked responses. Spatiotemporal patterns in click-evoked responses, observed by optical recording with voltage-sensitive dye, are analyzed by time series analysis using a multivariable autoregressive (MAR) model. Oscillatory neural activities with a distribution of about 10 approximately 40 Hz in the click-induced evoked responses are found in the cortical response field. The cortical regions where the distributed neural oscillations are generated are identified by pattern-time-series analysis. In addition, two types of cortico-cortical connections, unilateral and bilateral connections between the cortical points, are speculated to be the causes of oscillatory neural activity transfer. It can be said that the so-called synchronized neural oscillation, in the sense of coherency or correlation between the two evoked responses at the oscillatory frequency, does not necessarily represent real cortico-cortical neural connections at the evoked response points.

Animals↗

PubMed1995

Spontaneous rupture of the iliac vein: report of a case.

We report a rare case of a spontaneous rupture of the iliac vein which was then surgically treated with good results. A 66-year-old woman was admitted complaining of leg swelling and lower abdominal pain. On the 3rd day after admission, an operation was performed because of a gradually increasing hematoma in the retroperitoneal space. Laparotomy revealed a 17 mm longitudinal tear on the anterior surface of the left external iliac vein with a thrombus inside the lumen. Most of the previously reported 14 cases of this nature have required emergency operations.

Aged↗

PubMed1995

Extensive modifications for methionine enhancement in the beta-barrels do not alter the structural stability of the bean seed storage protein phaseolin.

Common beans are widely utilized as a food source, yet are low in the essential amino acid methionine. As an initial step to overcome this defect the methionine content of the primary bean seed storage protein phaseolin was increased by replacing 20 evolutionarily variant hydrophobic residues with methionine and inserting short, methionine-rich sequences into turn and loop regions of the protein structure. Methionine enhancement ranged from 5 to 30 residues. An Escherichia coli expression system was developed to characterize the structural stability of the mutant proteins. Proteins of expected sizes were obtained for all constructs except for negative controls, which were rapidly degraded in E. coli. Thermal denaturation of the purified proteins demonstrated that both wild-type and mutant phaseolin proteins denatured reversibly at approximately 61 degrees C. In addition, urea denaturation experiments of the wild-type and a mutant protein (with 30 additional methionines) confirmed that the structural stability of the proteins was very similar. Remarkably, these results indicate that the phaseolin protein tolerates extensive modifications, including 20 substitutions and two loop inserts for methionine enhancement in the beta-barrel and loop structures, with extremely small effects on protein stability.

Amino Acid Sequence↗

PubMed1995

Age-related changes in natural and fast walking.

Age-related changes in the relation between natural and fast walking were investigated for 69 healthy women aged 21 to 88 years. The ratio (fast/natural) of both walking velocity and cadence declined significantly across age groups.

Adult↗

PubMed1995

Gait disturbance of patients with vascular and Alzheimer-type dementias.

The gaits of 15 patients with senile dementia of the Alzheimer type and 15 with vascular dementia were compared with those of 15 healthy control subjects. Patients with senile dementia showed significantly slower velocity and shorter step length than the healthy controls, and those with vascular dementia exhibited a reduction on these two variables relative to patients with senile dementia of the Alzheimer type.

Accidental Falls↗