Search PubMed⌕ Search

Biomedical subjects

N Kitamura

Publications and source records attributed to N Kitamura.

At least 325 records · Page 18Linked to original sources
PubMed1993

[Autotransplantation as optimal technique for recurrent malignant myxoma of left ventricle].

Application of autotransplantation for left ventricular recurrent malignant tumor which was considered to be originating from the posterior leaflet of mitral valve was presented. A patient was 29 year-old-female and underwent the resection of tumor. The tumor was resected en bloc with the mitral valve, and its histology was myxoma. But she was required reoperation two times because of the recurrence of the tumor unfortunately. The tumor was ultimately diagnosed as the myxofibrosarcoma with chondroid differentiation. At the time of the third surgery, the heart transplantation was thought to be only treatment for radicality. While sounding American counterparts on the possibility of the heart transplantation, her condition took a sudden turn for the worse. An autotransplantation technique was applied for the resection of the tumor emergently. As a result, it was impossible to completely resect the tumor because of severe invasion to the left ventricle, and the patient died suddenly on the 75th day after the operation due to fetal arrhythmia. Through this case, heart transplantation should be considered for such a case, but autotransplantation technique allowed to be a life-prolonging in this case. We believe that this technique which will be obtained the excellent operative field could be used for repair of complex cardiac anomalies and rupture of left ventricle and so on.

Adult↗
PubMed1993

Histochemical localization of glycosaminoglycans in the omasal papillae of sheep.

Histochemical localization of the glycosaminoglycans in the omasal laminae were examined at light and electron microscopic levels. The core region of the omasal papillae was stained strongly with alcian blue at pH 2.5 and 1.0. The staining was degraded moderately and completely when tissue sections were pretreated with mild and active methylation, respectively. Alcianophilia was moderately decreased with saponification. Furthermore, enzymatic digestion procedures showed that these alcianophilic substances contained a large amount of hyaluronic acid and chondroitin sulphate. Ultrastructurally, a spider web-like structure was widely distributed among the spindle-shaped fibroblast-like cells and fibrous networks of collagen and elastin. These results suggest that the core region of the omasal papillae not only acts as a physical buffer resisting the local pressure from the lumen, but may also influence material transport through the omasal mucosa.

Animals↗
PubMed1992

Functional characterization of human hepatocyte growth factor mutants obtained by deletion of structural domains.

Human hepatocyte growth factor (hHGF) consists of characteristic structural domains. In this study, we prepared mutant proteins lacking each of these domains and examined their biological activities for stimulation of hepatocyte DNA synthesis, inhibition of Meth A cell growth, and induction of MDCK cell dissociation. We also examined their interactions with the c-met/HGF receptor by competition analysis and by analysis of levels of tyrosine phosphorylation. The mutant proteins lacking the N-terminal, the first kringle, or the second kringle domain were not biologically effective and could not compete with hHGF bound to the c-met/HGF receptor. The results indicate that these domains are necessary for the biological activities of hHGF mediated by binding to the c-met/HGF receptor. The mutant proteins lacking the third or fourth kringle domain moderately retained biological activities and the receptor binding. The relative levels of the tyrosine phosphorylation of the c-met/HGF receptor by these mutant proteins correlated well with the relative potencies of the biological activities when compared with that of the wild-type hHGF. The mutant protein lacking the light chain was not effective in the biological activities and tyrosine phosphorylation of the c-met/HGF receptor, but competed with hHGF bound to the c-met/HGF receptor. These results suggest that the heavy chain plays an important role in the interaction of hHGF with the c-met/HGF receptor and that the light chain is further required for the tyrosine phosphorylation of the c-met/HGF receptor.

Amino Acid Sequence↗
PubMed1992

The loss of beta II-protein kinase C in the striatum from patients with Huntington's disease.

We have examined the levels of protein kinase C (PKC) in autopsied brains of patients with Huntington's disease (HD), using [3H]4-beta-phorbol-12,13-dibutyrate ([3H] PDBu) and antisera against the PKC subspecies. In the caudate nucleus and putamen from patients with HD, the specific binding for [3H]PDBu was significantly decreased by 74 and 68%, respectively, as compared to findings in controls. The beta II-PKC immunoreactivities were significantly reduced by 65%, whereas the alpha-PKC immunoreactivities increased by 146%, in the putamen. There were no differences in the beta I- or gamma-PKC immunoreactivities in the putamen between HD and controls. These results suggest the differential localization of four PKC subspecies in human striatum and the involvement of four subspecies in different aspects of HD pathophysiology.

Brain↗
PubMed1992

Characterization of hepatocyte-growth-factor receptors on Meth A cells.

Hepatocyte growth factor (HGF) is a heparin-binding polypeptide mitogen for a variety of cell types including hepatocytes. HGF also has cytotoxic activity on some tumor cell lines as well as scattering activity on epithelial cells. In this study, recombinant human HGF was used to identify HGF-binding cell surface receptors on Meth A cells, whose growth is inhibited by HGF. Scatchard analysis of binding data indicated that there were two classes of binding sites with high affinity (Kd = 17 pM) and low affinity (Kd = 6.7 nM) and the average numbers were 6600 and 2,600,000 per cell, respectively. Affinity cross-linking of 125I-HGF to Meth A cells resulted in a major and a minor specifically labeled complex. Competition analysis followed by cross-linking indicated that the HGF-binding proteins were involved in the formation of the high-affinity binding. The existence of the two HGF-binding surface proteins was confirmed by HGF-dependent immunoprecipitation of the binding proteins with an anti-HGF polyclonal antibody. The molecular masses of the major and the minor surface proteins were 160 kDa and 130 kDa, respectively. The 160-kDa protein was autophosphorylated in vitro on tyrosine residue and was immunoprecipitated with an antiserum against the c-met proto-oncogene product. These results indicate that the 160-kDa HGF-binding surface protein on Meth A cells is the c-met protein. Furthermore, tyrosine phosphorylation of the c-met protein was stimulated by HGF treatment of Meth A cells, suggesting that it may be involved in the signal transduction of the growth inhibition of Meth A cells by HGF.

Amino Acids↗
PubMed1992

Expression of a human hepatocyte growth factor/scatter factor cDNA in MDCK epithelial cells influences cell morphology, motility, and anchorage-independent growth.

The addition of exogenous hepatocyte growth factor (HGF)/scatter factor (SF) to MDCK epithelial cells results in fibroblastic morphology and cell motility. We generated HGF/SF producing MDCK cells by transfection with an expression plasmid containing human HGF/SF cDNA. Production of HGF/SF by these cells induced a change from an epithelial to a fibroblastic morphology and increased cell motility. In addition, the HGF/SF producing cells acquired efficient anchorage-independent growth in soft agar but did not form tumors in nude mice. The morphological change and the stimulation of the anchorage-independent growth were prevented by anti-HGF/SF antibody, suggesting that the factor is secreted and then exerts its effects through cell surface receptors.

Animals↗
PubMed1992

Hepatocyte growth factor and transforming growth factor-beta stimulate both cell growth and migration of human gastric adenocarcinoma cells.

Hepatocyte growth factor (HGF) induced scattering and cell migration of human gastric adenocarcinoma MKN-74. HGF also significantly promoted the growth of MKN-74 cells in a dose-dependent manner, although HGF is reported to be antiproliferative for the growth of tumor cell lines. This result indicates that HGF stimulates cell proliferation of not only normal epithelial cells but also certain carcinoma cells. Furthermore, transforming growth factor-beta (TGF-beta), which is recognized to inhibit the growth of most epithelial cells, additively enhanced both the cell proliferation and migration induced by HGF. These additive effects of HGF and TGF-beta may be responsible for the tumor invasiveness and uncontrolled growth of certain types of carcinoma.

Adenocarcinoma↗
PubMed1992

Morphological study on the stomach of the lesser mouse deer (Tragulus javanicus) with special reference to the internal surface.

The stomach of the lesser mouse deer (Tragulus javanicus) was observed macroscopically. It consisted of only three compartments, rumen, reticulum and abomasum without omasum. The rumen was S-shaped with large ventral and caudoventral blind sacs and the reticulum was larger than the abomasum. Internally, the rumen was covered with numerous ruminal papillae even on the pillars and the ruminoreticular fold. These papillae were leaf- or tongue-like shaped and varied in size and density. The reticulum had honey-combed crests and the secondary crests were found rarely. The lips of the reticular groove were prominent and more developed in the aboral part than in the oral one. A sac-like transition zone, which had more prominent mucosal folds than had the floor of the reticular groove, was observed between the caudal end of the reticular groove and the abomasum. Mucosal folds of the abomasum were spiral, low but rather thick. These findings were discussed in view of comparison with other ruminants and of possible functional implications.

Animals↗
PubMed1992

[Clinical experience with the omnicarbon valve prosthesis].

Between January 1985 and March 1990, isolated valve replacements with the Omnicarbon valve were performed in 90 patients aged 34-72 years. There were 53 aortic valve replacements (AVR) and 37 mitral valve replacements (MVR). The cumulative follow-up was 320 patient-year (py) with a mean follow-up of 3.7 +/- 1.4 years. There were 3 operative and hospital mortalities (3.3%), resulting from retrograde aortic dissection during cardiopulmonary bypass, postoperative renal failure, and rupture of infective pseudoaneurysm in ascending aorta. Seven patients died during the late postoperative period, 4 due to valve-related causes. Two of these patients died of prosthetic valve endocarditis (PVE), while the others died of thromboembolism (including valve thrombosis). The overall actuarial survival rate at 6 years was 86.3% (98.8% for AVR, and 82.1% for MVR). There were 2 thromboembolic events (one mesenteric artery thrombosis, and the other valve thrombosis). The linearized incidence of thromboembolism was 0.63%/py. PVE occurred in 3 patients (0.94%/py). One patient (0.31%/py) was found to have a valve dehiscence due to aortitis syndrome. There were no instances of anticoagulant-related hemorrhage, or valve-related hemolysis. The actuarial rate of freedom from valve-related mortality at 6 years was 93.5% (100% for AVR, and 88.1% for MVR). On the basis of a follow-up period of 6 years, good clinical results and a low incidence of valve-related complications can be demonstrated with Omnicarbon valve.

Adult↗
PubMed1992

[Percutaneous transluminal coronary angioplasty in patients with previous coronary artery bypass grafting].

Percutaneous transluminal coronary angioplasty (PTCA) has been used to treat patients with previous coronary artery bypass grafting (CABG). Seven patients with previous CABG underwent coronary artery or vein graft angioplasty following a recurrence of symptoms. Fifteen lesions were attempted in 7 patients. The primary angiographic success rate was 100%. The primary angiographic success rate was defined as reduction of a stenosis by at least 20% of the vessel diameter, leaving a stenosis of less than 60%. There were no complications following PTCA such as death or myocardial infarction. No patients were referred for urgent surgery. Three patients have undergone another PTCA after 3 months and remain well. All patients at follow-up continue to have improved symptoms. Our experience suggests that the patients with recurrence of coronary artery or bypass stenosis following CABG may be suitable for PTCA.

Aged↗
PubMed1992

[A case report of Candida prosthetic endocarditis: an autopsy review].

Most of the increasing numbers of cases of Candida endocarditis have developed after cardiac surgery. We report a case of Candida parapsilosis endocarditis after mitral valve replacement in a patient with no predisposing factors. In this report we mainly examined the pathological findings in this patient with postmortem examination. A woman, age 55, underwent valve replacement with a Björk-Shiley prosthesis for mitral stenosis. The spike fever occurred on the 22nd postoperative day and Candida parapsilosis was cultured from the blood. On the 76th day, a conscious disturbance with the right side hemiplegia was experienced. A CT scan revealed massive hemorrhagic infarction. Despite the intensive care the patient died of cerebral damage. Pathologic findings showed that the vegetation in the major orifice of the Björk-Shiley valve was composed of both necrotic debris and tissue, with Candida organisms being scattered throughout the interstices. Additionally there were also multiple myocardial abscesses with necrotic tissue.

Candidiasis↗
PubMed1992

[Operative results with total composite replacement of the aortic valve and ascending aorta].

From December 1980 to December 1990, ten patients, 9 male and 1 female, ranging in age from 21 to 68 years, were operated on for aortic valve insufficiency associated with an aneurysm of the ascending aorta. The surgical treatment in all cases consisted of total replacement of the ascending aorta with Bentall's procedure (n = 4), or Cabrol's procedure (n = 6). In 5 patients an uncomplicated annulo-aortic ectasia existed. Three of them had annulo-aortic ectasia with an aortic dissection. One had aortitis syndrome, and one had syphilitic aortitis. The operative mortality for the entire group was 0% (0 death). Hospital survivors revealed satisfactory clinical improvement in NYHA class (mean value: 3.2 to 1.0). Late complications developed in 2 of the 10 patients. They had a picture of pseudoaneurysm formation at the anastomoses between the graft and the right coronary 46 months and 15 months, respectively, after the initial operation. Despite the reoperation, one died of hepatic failure 30 days after the operation, and the other died of postoperative bleeding at the anastomosis sites. We, furthermore, considered the difference in aortic cross clamp time and cardiopulmonary bypass time between Bentall's procedure and Cabrol's procedure. Aortic cross clamp time and cardiopulmonary bypass time were significantly shorter in Cabrol's procedure than in Bentall's procedure, if a probability value less than 0.20 was considered to be of statistical significance. We were able to conclude that the treatment of aortic valve regurgitation associated with an aneurysm of the ascending aorta by insertion of a composite graft is a reliable method with low operative mortality and excellent long term results, especially in Cabrol's procedure.

Adult↗
PubMed1992

[Pseudoaneurysm of the left ventricle following mitral valve replacement].

This report describes a false aneurysm of atrioventricular groove in the patients who underwent the reoperation of the mitral valve replacement (MVR). Patient 1 underwent reMVR with a SJM prosthesis because of the malfunction of the previous prosthetic valve. A large hematoma was observed in the posterior atrioventricular groove with bleeding at weaning from cardiopulmonary bypass. Ventricular rupture was repaired under the cardioplegic arrest successfully from the epicardial surface with a woven Dacron felt. The postoperative left ventriculogram revealed the false ventricular aneurysm along the atrioventricular groove. Patient 2 underwent reMVR with Carpentier-Edwards prosthesis because of the malfunction of the previous Carpentier-Edwards prosthesis. Cardiopulmonary bypass was discontinued uneventfully, and there were no clinical symptoms suspicious of the formation of the false left ventricular aneurysm. The left ventriculogram at the discharge showed the false left ventricular aneurysm along the atrioventricular groove. Although both patients are in good condition without significant complications, we should involve in the postoperative care of the patients on a regular outpatient basis.

Aged↗
PubMed1992

[Comparative study of anticoagulant management after coronary artery bypass surgery--warfarin versus dipyridamole].

A prospective randomized study was performed in 137 coronary artery bypass surgery cases to determine if the administration of antiplatelet drugs would improve the patency of coronary artery bypass grafts. The warfarin group received warfarin and thrombotest was controlled to 20% or so. The dipyridamole group received both 300 mg of dipyridamole and 250 mg of aspirin orally each day. These two groups were compared for study in grafts patency. Results were analyzed by chi-square. In the warfarin group, 66 patients had three ITA-LAD grafts and 115 saphenous vein grafts (including 4 sequential grafts). In the dipyridamole group, 71 patients underwent 38 ITA grafts and 167 saphenous vein grafts (including 56 sequential grafts). Eighty-eight of the 107 grafts (82%) were patent in the warfarin group, and 190 of 205 grafts (95%) were patent in the dipyridamole group (p less than 0.01). Of the two ITA grafts in the warfarin group, no graft was occluded, a patency of 100%. In the dipyridamole group, 35 of 38 ITA grafts (92%) were patent. In the warfarin group, 86 of 105 saphenous vein grafts (82%) were patent. In the dipyridamole group, 155 of 167 saphenous vein grafts (95%) were patent (p less than 0.01). In the study of grafted coronary vessel, the patency of left anterior descending coronary artery, diagonal branch and right coronary artery was not significant between two groups. In the dipyridamole group, the patency of left circumflex coronary artery was 93%, and that of the warfarin group was 50% (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Primary structure of protein moiety of Penicillium notatum phospholipase B deduced from the cDNA.

Phospholipase B has not yet been well defined. The most important points about this enzyme are its relationships with lysophospholipase and phospholipase A1. As reported [Saito, K., Sugatani, J. & Okumura, T. (1991) Methods Enzymol. 197, 446-456], Penicillium notatum phospholipase B is a glycoprotein with a molecular mass of 95 kDa and intrinsic lysophospholipase and phospholipase B activities; however, by endogenous proteolytic modification, its phospholipase B activity is lost almost completely, whereas its lysophospholipase activity remains unchanged. A cDNA library of P. notatum was screened by hybridization with two synthetic oligodeoxyribonucleotide probes, which corresponds to two different pentapeptides of the enzyme. A hybridization-positive clone, pPLB18, was isolated and its nucleotide sequence was determined. The deduced amino acid sequence was quite different from that found previously. Therefore, we rescreened the cDNA library with a Sau3AI fragment derived from pPLB18 and isolated a new clone, pPLB15. Comparison of the nucleotide sequences of pPLB15 and pPLB18 revealed that pPLB18 contained an insertion sequence of 53 bp. Consequently, the reading frame was open downstream for 603 amino acid residues. From the assigned sequence, it was deduced that the limited proteolysis occurred between Leu175 and Asp176; eight cysteine residues and 16 potential N-glycosylation sites were also found. No amino acid sequence similarity was found with other proteins, including other phospholipases.

Amino Acid Sequence↗
PubMed1991

Structural organization and the transcription initiation site of the human hepatocyte growth factor gene.

The structural organization of the gene coding for human hepatocyte growth factor (hHGF) has been determined by seven overlapping lambda phage genomic clones including three clones that were previously characterized. The gene for hHGF spans about 70 kbp of DNA and consists of 18 exons separated by 17 introns. The coding sequence of hHGF consists of multiple putative domains that are homologous to those observed in plasminogen. These regions were found as separate exons in the gene, and the exon-intron arrangement was similar to that of plasminogen. These results suggest that the genes for hHGF and plasminogen have arisen through gene duplication events from an ancestral gene. The major transcription initiation site of the hHGF gene is located 76 bp upstream of the translational start codon as judged by S1 nuclease mapping and primer extension analyses. A TATA-like element was found 33 nucleotides upstream of the transcription initiation site. Two sequence elements, an interleukin 6 response element (CTGGGA) and a potential binding site for NF-IL6 (TGAGGAAAG), are located near the transcription initiation site. These sequence elements might be involved in the regulation of HGF gene expression.

Amino Acid Sequence↗
PubMed1991

Decreased histamine H1 receptors in the frontal cortex of brains from patients with chronic schizophrenia.

Involvement of histamine H1 receptor in the brains of schizophrenic patients was investigated using 3H-mepyramine as a ligand. The specific 3H-mepyramine binding in the frontal cortex was saturable with the dissociation constant (Kd) of about 0.6 nM and the maximum number of binding sites (Bmax) of 64 fmol/mg protein. Specific H1 antagonists, mepyramine (Ki = 1.4 nM), promethazine (Ki = 1.4 nM), diphenylpyraline (Ki = 4.1 nM), triprolidine (Ki = 5.3 nM), diphenylhydramine (Ki = 35 nM), but not the specific H2 antagonist, cimetidine (Ki greater than 10(5) nM), strongly inhibited the 3H-mepyramine binding. Regional distribution of the specific 3H-mepyramine binding was in the order of: frontal cortex greater than hippocampus greater than cerebellum greater than hypothalamus greater than thalamus, putamen, and pallidum. The specific 3H-mepyramine binding in schizophrenic brains was reduced by 56% in the frontal cortex. Representative Scatchard analyses of the specific 3H-mepyramine binding revealed changes resulting from a decrease in receptor density but not in receptor affinity. Down-regulation of the histamine H1 receptor in the frontal cortex may be involved in the pathophysiology of schizophrenia.

Adult↗