Biomedical subjects

T Murakami

Publications and source records attributed to T Murakami.

At least 469 records · Page 26Linked to original sources

PubMed1998

Increases in the mitochondrial DNA replication and transcription in the remnant liver of rats.

We studied mitochondrial DNA (mtDNA) replication and transcription in association with major hepatectomy. Changes in nuclear respiratory factor 1 (NRF-1) mRNA and RNA moiety of mitochondrial RNA-processing endoribonuclease (MRP-RNase RNA) were followed at 0, 3, 6, 12, and 24 h after hepatectomy. Contents of mtDNA, cytochrome b mRNA, and beta-actin mRNA were also measured. Contents of NRF-1 mRNA and MRP-RNase RNA increased to maximum or sub-maximum level 1 h after hepatectomy. mtDNA and cytochrome b mRNA increased to maximum level 3 h after. On the contrary, content of beta-actin mRNA increased to maximum level 12 h after. From these results, mtDNA replication and transcription occurred in the initial phase of liver regeneration, which might lead to an increase in mitochondrial respiratory function in the remnant liver, and cytoskeleton proteins such as beta-actin were followed thereafter.

Actins↗

PubMed1998

Human T-cell leukemia virus type 1 Tax protein induces the expression of lymphocyte chemoattractant SDF-1/PBSF.

We investigated the mechanism of lymphocyte infiltration into tissues infected with human T-cell leukemia virus type 1 (HTLV-1). The cytokine SDF-1/PBSF is a highly efficient chemoattractant for lymphocytes. Reverse transcription-PCR analysis showed that among various human T-cell lines, those infected with HTLV-1 selectively expressed the SDF-1 gene. Expression of the viral protein Tax in a human T-cell line induced the expression of the SDF-1 gene, indicating that the constitutive expression of SDF-1 in virus-infected cell lines is at least in part mediated by Tax. HTLV-1-infected T-cell lines also expressed CXCR-4, a receptor for SDF-1. Moreover, chemotaxis assay showed that a HTLV-1-infected cell line migrated toward synthetic SDF-1. Thus, HTLV-1-infected cells are themselves responders for SDF-1. Our results suggest that SDF-1 induced by Tax may alter the distribution of HTLV-1-infected cells in vivo; hence it may contribute to their infiltration into affected tissues in HTLV-1-associated inflammatory diseases.

Animals↗

PubMed1998

Ethanolamine stimulates repair processes in acute CCl4 damage of mouse liver.

Ethanolamine, a positively charged hydrophilic component of the phosphatidylethanolamine (PE) which is also a precursor of phosphatidylcholine (PC), enhances the repair processes 24 h after carbon tetrachloride (CCl4) intoxication of mouse liver. Ethanolamine quickly reduced aminotransferase activity released in the serum, increased the hepatocellular nuclear BrdU uptake, a marker of S phase, and the epidermal growth factor (EGF) receptor content in the liver injured with CCl4. Thus, exogenous administration of ethanolamine may function as a liver proliferating factor in CCl4 intoxicated mouse liver.

Alanine Transaminase↗

PubMed1998

Skeletal muscle metabolism in maximal bicycle and treadmill exercise distinguished by using in vivo metabolic freeze method and phosphorus-31 magnetic resonance spectroscopy in normal men.

This study indicates that skeletal muscle metabolism may affect the results of maximal bicycle and treadmill exercise differently, and that maximal bicycle exercise was limited by quadriceps muscle metabolism rather than by cardiopulmonary capacity. In contrast, maximal treadmill exercise was not limited, eliciting more cardiopulmonary reserve and attaining greater peak oxygen uptake than maximal bicycle exercise.

Adult↗

PubMed1998

Intramembrane structure of the sensory axon terminals in bullfrog muscle spindles.

Much physiologic and morphologic research has been done into the sensory mechanism of the frog muscle spindle. However, no freeze-fracture study has described in detail the shape and intramembrane structure of the nonmyelinated sensory axon terminals of the frog muscle spindle. In this study, muscle spindles were isolated from the red part of bullfrog semitendinous muscles. Chemically fixed spindles were subjected to freeze fracturing. The sensory axon endings were reconstructed, and the size and density of intramembrane particles (IMPs) were measured along the sensory nerve endings. The axon terminals had four distinctive parts: parent trunks (>0.5 microm in diameter), primary branches (0.15-0.5 microm), terminal branches (<0.1 pm), and varicosities (0.02-0.5 microm). IMPs ranged from 5 nm to 21 nm in diameter and were present in the intramembrane space of the plasma membrane all throughout the nonmyelinated sensory nerve endings. Mean IMP sizes in the protoplasmic face (PF) and the external face (EF), respectively, were 8.1 nm and 8.4 nm in the parent trunks, 8.8 nm and 8.8 nm in the primary branches, 9.4 nm and 9.0 nm in the varicosities, and 8.7 nm and 8.7 nm in the terminal branches. Mean IMP size in the PF was smallest in the parent trunk and largest in the varicosity. Mean IMP densities (numbers of IMPs per microm2) in the PF and the EF, respectively, were 2,500 and 700 in the parent trunks, 2,200 and 500 in the primary branches, 1,700 and 400 in the varicosities, and 1,000 and 300 in the terminal branches. Density decreased with the tapering of the axon terminal, with IMPs distributed evenly in the PF and the EF. The characteristic intramembrane structure of sensory nerve endings is discussed.

Animals↗

PubMed1998

Characteristics of cardiac hypertrophy in the juvenile visceral steatosis mouse with systemic carnitine deficiency.

The juvenile visceral steatosis (JVS) mouse exhibits hereditary systemic carnitine deficiency and develops cardiac hypertrophy. The aim of this study was to clarify the characteristics of cardiac hypertrophy in the JVS mouse. Total carnitine content in IVS mouse heart was about 10% of that of control mouse heart at 4 and 8 weeks of age. The heart weight/body weight ratio was bigger in JVS mice than that in control mice at 2 weeks of age, and this difference in ratio increased with age. The wall areas of both ventricles and septum in JVS mice were larger than those of the control mice at 2 and 8 weeks. The myocyte diameter in both ventricular walls and septum in JVS mice was longer than that of the control mice. On electron microscopy, the percent of mitochondria in the myocyte was 66% in JVS mice, and 37% in control mice. The percent of lipid fraction in JVS mice was six-fold higher than that in control mice. Total content of adenine nucleotides in JVS mouse heart was about 60% of that in control mouse heart. Adenylate energy charge in JVS mouse heart was 63 and 45% of that in the control mouse heart at 4 and 8 weeks, respectively. Overall, the cardiac enlargement observed in this animal model could be accounted for by a proportional increase in the myocyte diameter in the ventricles and septum, accompanied by an increase in mitochondria. Furthermore, this cellular growth is associated with decreases in the levels of ATP and ADP, and adenylate energy charge.

Adenosine Diphosphate↗

PubMed1998

Expression of the alpha 1 and alpha 2 chains of type IV collagen in the infarct zone of rat myocardial infarction.

Healing processes affect ventricular remodeling, an important prognostic factor in acute myocardial infarction (AMI). Type IV collagen, a major component of the basement membrane, has been demonstrated to appear in the infarct zone. Six type IV alpha chains, alpha 1 to alpha 6 [alpha 1(IV) to alpha 6(IV)], have been identified. We examined the expression of the alpha 1(IV), alpha 2(IV), alpha 3(IV) and alpha 5(IV) in experimental rat AMI induced by permanent ligation of the left coronary artery in male Sprague-Dawley rats. Neonatal cardiac fibroblasts cultured to reach confluency were also used to examine the hypoxic induction of the expression of these chains. Northern blotting, in situ hybridization, and immunohistochemical staining were employed to examine the alpha chain expression. With the in situ hybridization, alpha 1(IV) and alpha 2(IV) mRNA signals were observed in spindle-shaped mesenchymal cells in the intercellular spaces, in the vascular endothelial cells and in some myocytes in the normal myocardium. Signals for both alpha 1(IV) and alpha 2(IV) mRNA appeared in the spindle-shaped mesenchymal cells located between the surviving myocytes in the infarct peripheral zone at 24 h after the ligation. These signals extended into the central zone and reached the center point of the infarct 5 days after the ligation. Neither alpha 3(IV) nor alpha 5(IV) mRNA signals were observed in the infarct zone. Northern blotting demonstrated increased expressions of alpha 1(IV) and alpha 2(IV) mRNA in the infarct zone compared to the sham-operated hearts. The expression of alpha 5(IV) mRNA was weak in the sham-operated hearts but was not detected in the infarct zone. alpha 3(IV) mRNA was not expressed in the infarct zones or sham-operated hearts. In the cultured cardiac fibroblasts, a hypoxic induction of the expression of both alpha 1(IV) and alpha 2(IV) mRNA was demonstrated by Northern hybridization. Immunohistochemistry revealed alpha 1(IV) and alpha 2(IV) staining in the infarct lesion. The findings demonstrate that among the type IV collagen alpha chains examined, alpha 1(IV) and alpha 2(IV) produced by mesenchymal cells appeared in the infarct zone, suggesting that type IV collagen composed by alpha 1 and alpha 2 chains contributes to the pathological course of myocardial infarction.

Animals↗

PubMed1998

Increased expression of connective tissue growth factor in the infarct zone of experimentally induced myocardial infarction in rats.

Connective tissue growth factor (CTGF), a 36- to 38-kDa peptide, is selectively induced by transforming growth factor-beta and has been suggested to contribute to tissue repair. To test the hypothesis that CTGF is expressed in myocardial infarct tissue following acute myocardial infarction (AMI), we examined CTGF expression after AMI was experimentally induced in rats. Myocardial infarction was induced by left coronary artery ligation in male Sprague-Dawley rats. Northern blotting demonstrated that the CTGF mRNA expression on days 2, 7 and 14 was increased by 6-, 23- and 8-fold, respectively, compared to that in the pre-ligation hearts. In situ hybridization revealed CTGF mRNA signals on day 2 in myocytes in the infarct marginal zone and spindle-shaped mesenchymal cells (presumably myofibroblasts and fibroblasts) located between surviving myocytes in the infarct peripheral zone. On day 7, the signals were observed in the inner lesion of the infarct around infarct granulation tissue. Western blotting demonstrated that the CTGF protein expression on days 2, 7 and 14 was increased compared to the pre-ligation hearts. Immunopositive staining for CTGF was observed in the inner lesion of the infarct tissue on day 7. In conclusion, the findings demonstrated the increased expression of CTGF in the infarct tissue. Myocytes in the infarct marginal zone and spindle-shaped mesenchymal cells (presumably myofibroblasts and fibroblasts) were the cells responsible for CTGF production.

Animals↗

PubMed1998

Peutz-Jeghers syndrome manifesting complete intussusception of the appendix and associated with a focal cancer of the duodenum and a cystadenocarcinoma of the pancreas: report of a case.

The unusual occurrence of an "inside-out" appendix reported here is a case of complete intussusception of the appendix of a 45-year-old woman with Peutz-Jeghers syndrome in whom the diagnosis of intussusception was made preoperatively. At laparotomy, the lead point of intussusceptum was revealed to be a Peutz-Jeghers syndrome polyp of the appendix. There was also a cystic lesion in the pancreas, and subsequent distal pancreatectomy revealed a cystadenocarcinoma of the pancreas. Two jejunal Peutz-Jeghers syndrome polyps and two duodenal Peutz-Jeghers syndrome polyps were found via intraoperative endoscopies. The duodenal polyps were endoscopically removed, whereas a jejunal wedge resection was performed for the adjoining jejunal polyps. One of the two duodenal polyps possessed an adenocarcinoma focus. To our knowledge, this is the first report of complete intussusception of the appendix caused by a Peutz-Jeghers syndrome polyp.

Appendiceal Neoplasms↗

PubMed1998

[Surgical treatment for a 16-year-old girl with anomalous origin of the right pulmonary artery from ascending aorta].

Anomalous origin of the right pulmonary artery is a rare congenital malformation and is usually fatal without early surgical correction. A 16-year-old patient, who had received no previous treatment, demonstrated abnormal findings on ECG. On cardiac catheterization, the pressure in the normally arising left pulmonary artery was found to be greater than the systemic level. Bidirectional shunting across a patent ductus was identified and aortography revealed that the right pulmonary artery arose from the posterior wall of the proximal ascending aorta. The presence of severe pulmonary vascular obstructive disease was anticipated and right lung biopsy was performed. The index of pulmonary vascular disease rating was 2.8 and the Heath-Edwards classification was grade 3. Consequently, we considered that corrective right pulmonary circulation could be maintained after correction, and total correction was performed. The postoperative course was uneventful and the pulmonary artery pressure reduced significantly. Discussion focuses on the surgical indications for such infrequent older cases and we conclude that preoperative lung biopsy is useful in identifying severe pulmonary vascular disease and evaluating indications for surgery.

Adolescent↗

PubMed1998

Aortic and mitral valve replacement in an 83-year-old female. 3 years follow-up of 16 mm bileaflet valve at the aortic position.

An 83-year-old female with aortic and mitral stenosis showed orthopnea. The aortic valve pressure gradient was 139 mmHg. The mitral valve orifice was 0.92-1.05 cm2 and the right ventricular pressure was 70 mmHg. The body surface area of the patient was 1.23 m2. Double valve replacement was performed with 16 mm CarboMedics pediatric bileaflet valve for the aortic position and 25 mm CarboMedics mitral valve for the mitral position. The patient leads a normal daily life with NYHA class II three years after surgery.

Aged↗

PubMed1998

[Primary leiomyosarcoma of the heart, report of a case and review of the literature].

Primary cardiac neoplasms are unusual and are found in only about 0.0017% of autopsies. Approximately 25% of primary cardiac neoplasms are malignant. A case of primary leiomyosarcoma arising from the right ventricle and the pulmonary artery is reported. A 37-year-old man had sudden dyspnea and chest pain. Angiocardiography and MRI revealed moving masses throughout the right ventricle and the pulmonary arteries. An emergent surgery was performed. The multiple tumors were observed and incomplete resection was done. The patient was survived with the aid of a veno-arterial bypass as an assisted circulation on the first postoperative day. However, he gradually became deteriorated again and died 8 days after the operation due to the right ventricular failure. Eleven cases of the primary cardiac leiomyosarcoma including our case in the Japanese literature were reviewed briefly.

Adult↗

PubMed1998

[An emergent operation for metastatic cardiac tumor of malignant cystosarcoma phyllodes].

A 47-year-old woman was transferred to our hospital under endotracheal intubation with severe hemodynamic deterioration. A left mastectomy had been performed 8 months earlier and histology of the specimen showed malignant cystosarcoma phyllodes. An angiography and echocardiography suggested massive mass of the right ventricle extending to the pulmonary artery. An emergent life-saving operation was required using cardiopulmonary bypass. A huge multilobular tumor was resected from the right ventricle through the pulmonary artery as much as possible and a tricuspid valvuloplasty was also performed. The patient was weaned from cardiopulmonary bypass, then satisfactorily recovered from hemodynamic disturbances. Nevertheless, she died 15 days later due to multiple organ failure. Microscopic examination of resected specimen showed the neoplastic stromal cells that increase mitotic activity and have sarcomatous characteristics, consistent with a metastatic cystosarcoma phyllodes. This is a second case of operation for cardiac metastasis of cystosarcoma phyllodes using cardiopulmonary bypass, so far presented in the literature of the world reviewed by the authors.

Breast Neoplasms↗

PubMed1998

[A case of ruptured descending thoracic aortic aneurysm due to Salmonella infection].

A 66-year-old male was admitted to our hospital because of pyrexia, chest pain and hemosptum. Inflammatory findings were made and salmonella enteritidis was detected by bacterial examination of sputum and stool. Enhanced chest CT examination disclosed a descending thoracic aortic aneurysm which had ruptured into the left lower lobe of the lung. Under a diagnosis of ruptured mycotic descending thoracic aortic aneurysm, an emergency operation was performed. A left posterolateral thoracotomy carried out after axillo-bilateral femoral bypass grafting. A pseudoaneurysm of the descending thoracic aorta had ruptured into the left lower lobe of the lung. After resection of the aneurysm, closure of both ends of the intact descending thoracic aorta and a left lower lobectomy were carried out. An ascending aorta-infrarenal abdominal aorta bypass was performed because of insufficient visceral arterial blood flow through the axillo-bilateral femoral bypass. The patient's immediate postoperative recovery was complicated by paraplegia. Chloramphenicol and levofloxacin were administered for three months, after which his recovery followed a good course.

Aged↗

PubMed1998

Ovarian hormone-induced beta-cell hypertrophy contributes to the homeostatic control of beta-cell mass in OLETF female rat, a model of Type II diabetes.

A sexual dimorphism regarding the incidence of diabetes mellitus in OLETF rat, a model of Type II diabetes, has been reported. As a result, the effects of ovarian hormones on beta cells per se was examined by comparing the capacity of beta-cell proliferation and changes in blood glucose and plasma insulin concentrations after a 70% pancreatectomy. All female animals were randomly assigned to two protocols. The rats involved in protocol I received either a 70% pancreatectomy (Px) or a sham pancreatectomy (sham) at 6 weeks of age, along with their diabetes-resistant counterparts, female LETO rats, which served as normal controls. The rats belonging to protocol II were given an ovariectomy (Ox) at 5 weeks of age, and one week later, they were subjected to either Px or the sham operation, with/without hormone (estradiol, 50 microg/kg; testosterone, 1 mg/kg) replacement. The findings indicate that the capacity for compensatory growth of beta cells after Px was affected by both sex hormonal and genetic components, since a 70% Px resulted in sustained hyperglycaemia within the first week after surgery, but was ameliorated by an increase in beta-cell mass thereafter in the non-Ox Px OLETF rats. The Ox also caused a decline in beta-cell mass which could be improved by replacement with ovarian hormones. Not only endogenous but also replacement ovarian hormones, led to a beneficial effect on beta cells per se in OLETF female rats. This was reflected by an increased beta-cell mass accompanied by a parallel increase in plasma immunoreactive insulin concentration. The effects of ovarian hormones, however, contributed to the beta-cell hypertrophy rather than expansion of the beta-cell population to achieve glucose homeostasis, as evidenced by an increased area of individual beta-cell after Px rather than an increased BrdU-labelling index for the beta cells. The present study suggests that ovarian hormone-induced beta-cell hypertrophy may typically occur, to compensate for changes in functional demand as the results of a 70% Px in female OLETF rats.

Animals↗

PubMed1998

Localization of a serine proteinase inhibitor, B-43, in the bovine pancreas.

B-43, a serine proteinase inhibitor belonging to the ovalbumin branch of the serpin superfamily, was purified and cloned from bovine brain. Since [35S]-labeled B-43 forms SDS-stable complexes with pancreatic serine proteinases, trypsin, alpha-chymotrypsin, and kallikrein, it has been suggested that B-43 is capable of inhibiting these serine proteinases and that B-43 may be present in the pancreas. In the present study, we investigated the localization of B-43 in the bovine pancreas immunohistochemically and examined the effect of B-43 on the amidolytic activities of pancreatic serine proteinases. Strong B-43-like immunoreactivity was localized in acinar cells, especially in the basal sides of the cells where the rough endoplasmic reticulum is located. The nuclei of the subpopulation of acinar cells were also immunoreactive for B-43. The recombinant glutathione S-transferase-B-43 fusion protein inhibited the amidolytic activity of trypsin and, to a lesser extent, alpha-chymotrypsin and kallikrein, but not elastase. These results suggest a role of B-43 in regulating serine proteinases both in the cytoplasm and the nucleus.

Animals↗

PubMed1998

Cannulation-induced coronary artery dissection: successful management with circulatory assist devices and coronary bypass grafting.

A coronary artery dissection is a rare but well-known lethal complication associated with coronary perfusion. We herein report the case of a right coronary dissection that occurred after an aortic valve replacement. Coronary bypass grafting was successful after the establishment of mechanical biventricular support with an intra-aortic balloon pump and a right ventricular assist device.

Aortic Valve↗

PubMed1998

Artificial chordae for mitral valve reconstruction in children.

BACKGROUND: Congenital mitral regurgitation continues to present a challenge for cardiac surgeons because of the diversity of the anatomy of the congenitally malformed mitral valve. We undertook aggressive repair of the mitral valve with artificial chordae for reconstruction of the prolapsed anterior leaflet in some children. The short-term results are reported herein. METHODS: Three patients with isolated congenital mitral regurgitation underwent mitral valve repair with use of expanded polytetrafluoroethylene sutures as artificial chordae. RESULTS: There have been no late deaths and no valve-related complications. Serial follow-up echocardiographic examinations have not revealed any increase in the severity of mitral regurgitation with continuing patient growth up to 39 months after the operation. CONCLUSIONS: When combined with other conservative methods of mitral valve repair, chordal replacement with expanded polytetrafluoroethylene sutures in children undergoing mitral valve reconstruction produces good short-term results. We believe that it delays and possibly prevents the need for a mechanical prosthesis with its associated complications in this young patient population.

Cardiac Volume↗