Biomedical subjects

T Murakami

Publications and source records attributed to T Murakami.

At least 577 records · Page 32Linked to original sources

PubMed1998

[Simultaneous MIDCAB and subtotal gastrectomy in an elderly patient with severe ischemic heart disease].

An 81 year old man with severe ischemic heart disease and left ventricular dysfunction was scheduled for a subtotal gastrectomy for his advanced gastric cancer. His cardiac function was so poor that we performed minimally invasive coronary artery bypass grafting (MIDCAB; coronary artery bypass grafting without cardiopulmonary bypass for LAD through a small left thoracotomy), just before the abdominal operation. Anesthesia was induced and maintained with fentanyl, vecuronium and sevoflurane. To control heart rate below 60 bpm during local coronary occlusion for bypass grafting, edrophonium 5 mg was administered just before the occlusion. During the bypass grafting procedure, the patient's heart rate was maintained at 50-60 bpm and his hemodynamic profile slightly declined but was permissible. After bypass grafting, his cardiac performance was improved with low dose dobutamine. Subsequently subtotal gastrectomy was carried out. His postoperative course was uneventful. Combined MIDCAB and abdominal operation may be beneficial for selected patients with severe ischemic heart disease.

Adenocarcinoma↗

PubMed1998

[Long-term follow-up of patients with small St. Jude aortic valve prostheses].

Thirty-five patients received small sized 19 or 21 mm valves (group I) and 53 patients received 23 or 25 mm valves (group II). At follow-up a significant reduction in the left ventricular mass was found for both patient groups (p < 0.0001). The patients in group I had higher peak pressure gradients than did those in group II. However, there was no significant difference between the two groups, or any significant correlation between peak pressure gradients and body surface area. Actuarial survival was 84.7% at 15 years for group I and 85.9% at 17 years for group II. Actuarial freedom from valve-related events was 91.4% at 15 years for group I and 82.7% at 17 years for group II. There was no significant difference in survival or valve-related event free curves between the two groups. After implantation of small SIM valves, significant left ventricular mass regression was obtained and the results were comparable to those for valves of other sizes. The long-term performance of aortic valve replacement with small valves was satisfactory as judged by improvement in the functional class of patients, survival statistics, the durability of the prosthesis, and valve related morbidity comparable to that of valves of other sizes.

Aged↗

PubMed1998

[Clinical role of magnetic resonance imaging (MRI) of prostatic cancer].

Magnetic resonance imaging (MRI) has become very important tool for diagnosis in many fields including neurology and orthopedics. In this article, the usefulness and current status of MRI in the clinical diagnosis of prostate cancer are discussed. The advantage of MRI over the other methods like ultrasound imaging and CT scan is that zonal anatomy of the prostate gland is clearly identified into peripheral, central and transition zone. Cancer in the peripheral zone is demonstrated as a low intensity lesion in T2-weighted images but cancer in other zones are difficult to be identified. Extracapsular invasion, seminal vesicle invasion and neuro-vascular invasion can be identified which is useful for the assessment of tumor extension. MRI is also useful for the detection of bone metastasis.

Humans↗

PubMed1998

[A case of primary cardiac malignant fibrous histiocytoma].

In this article, we report a case of primary cardiac malignant fibrous histiocytoma. The patient, 74-year-old female, had been treated medically for heart failure with minimal improvement and was referred to our hospital. Echocardiogram revealed two cardiac tumors in the left atrium, one of which was obstructing the inflow of the mitral valve. Emergent surgical resection was performed successfully with shortterm ICU stay, but the patient died of DIC on the 24th day after surgery. The pathological examination revealed malignant fibrous histiocytoma and this report is the 40th case report of this kind of primary cardiac tumor.

Aged↗

PubMed1998

Harmonic scalpel in coronary artery bypass surgery.

We used the harmonic scalpel (an ultrasonic cutting and coagulating instrument) in coronary artery bypass surgery. The gastroepiploic artery was harvested using coagulating shears. The operating time was reduced without shortening or twisting of the artery. The blade-type was used for hemostasis around the coronary artery and also in dissecting adhesion in redo surgery without any arrhythmias. The absence of electric current passing through the patient contributes to the safety of the harmonic scalpel in coronary artery bypass surgery.

Coronary Artery Bypass↗

PubMed1998

[Advanced hepatocellular carcinoma: therapeutic results in 110 patients and therapeutic strategy].

The prognoses of 110 patients with advanced hepatocellular carcinoma (HCC) in stages III and IV were studied retrospectively. These patients were treated mainly by transarterial chemoembolization (TAE) or chemoinfusion using Lipiodol. Some of the patients underwent percutaneous ethanol injection therapy (PEIT) or tumor resection following TAE. Hepatic function, tumor stage, vascular involvement, type of tumor invasion, number of tumors and number of treatments affected the prognosis of the patients. The prognosis was better in the Child A group than in Child B and C. In the Child C group, the prognosis was markedly poor, and was least affected by any treatment. The prognoses in the patients with multiple nodular lesions, massive or diffuse lesions, were much poorer than those with a few nodular lesions. Tumor thrombosis in the central portal vein and distant metastasis greatly exacerbated the therapeutic results. Repeat therapy yielded a favorable therapeutic result when hepatic function was tolerable. Surgical intervention and PEIT were an effective therapy in a few patients. In advanced HCC, liver function and tumor extension should be fully evaluated, and it is important to determine the most effective therapeutic modalities to improve the survival of patients.

Adult↗

PubMed1998

Time-dependent changes of serum carboxy-terminal peptide of type I procollagen and carboxy-terminal telopeptide of type I collagen concentrations in patients with acute myocardial infarction after successful reperfusion: correlation with left ventricular volume indices.

To test the hypothesis that in patients with acute myocardial infarction (AMI), changes in the concentrations of the serum carboxy-terminal peptide of type I procollagen (PICP) and the carboxy-terminal telopeptide of type I collagen (ICTP) reflect extracellular matrix reformation and degradation, respectively, in the infarct healing processes, we measured these serum concentrations by RIA and compared their values with left ventricular (LV) indices obtained by left ventriculography. We studied 13 consecutive patients with their first AMI who underwent successful reperfusion. Blood samples were taken the day of admission and on days 2, 3, 4, 5, 7, and 14. LV volume indices were determined at 1 month after AMI, when LV remodeling was almost completed. The serum concentrations of both PICP and ICTP changed in a time-dependent manner. The average serum PICP concentration was lower than 1 SD below the mean control values on days 2 and 3 and increased thereafter, returning to the lower end of the control range at day 14. The area under the curve (AUC) for PICP was significantly correlated with the LV end systolic (ES) and end diastolic (ED) volume indices and LV ejection fraction for the first 14 days after AMI. The serum PICP on days 5-14 was inversely correlated or tended to be correlated with the LVES and LVED volume indices. The average serum ICTP concentrations on admission were within the control range, began to increase on day 2, and reached maximal concentrations on day 5, remaining at a plateau concentration until day 14. Although the AUC of ICTP for 14 days, the ICTP concentrations on days 1 and 14, and the minimal and maximal concentrations were significantly correlated with creatine kinase (CK) release and the period from AMI onset to the peak CK time, the concentrations were not significantly correlated with any LV indices except for the concentration on day 4, which was weakly correlated with the LVES volume index. The serum concentrations of PICP showed a significant time-dependent change that correlated with LV indices, indicating that PICP may provide additional information for evaluating the healing process because it affects LV remodeling after AMI. Although the serum concentration of ICTP changed in association with CK release, the ICTP concentration was found to be a poor indicator for LV indices.

Adult↗

PubMed1998

Effect of partial pancreatectomy on beta-cell mass in the remnant pancreas of Wistar fatty rats.

Wistar fatty rat, which has been established by transferring the fa gene of Zucker fatty rat to the Wistar Kyoto rat, has many features in common with human NIDDM. It exhibits hyperglycemic obesity with hyperinsulinemia and insulin resistance. It is unclear, however, whether a defect in the beta-cell proliferation is related to the onset of diabetes mellitus together with insulin resistance in this model rat. To determine this, we compared non-fasting plasma glucose levels, insulin content and beta-cell mass in the remnant pancreas of Wistar fatty rats with those in their diabetic-resistant lean counterparts after a 70% partial pancreatectomy. We also examined whether such a defect, if present, could be improved by either phlorizin or nicotinamide. We further investigated if there were any differences in these parameters between the phenotypically identical but genotypically different Wistar lean rats with a gene type of homogeneous Fa/Fa and that of heterogeneous Fa/fa. Male rats, 6 weeks of age, were allocated at random into two groups: 70% pancreatectomy (Px) and sham-pancreatectomy (sham). A sustained hyperglycemia was evident in the Px Wistar fatty rats after surgery, which was accompanied by a reduction of insulin content and beta-cell mass in the remnant pancreas. The changes in insulin content and beta-cell mass were unaffected by restoration of normoglycemia, induced by phlorizin injection. The administration of nicotinamide partially ameliorated the sustained hyperglycemia by a slight but not significant increase in beta-cell mass. No discernible difference in the above parameters was observed between the Wistar lean rats with Fa/Fa and those with Fa/fa. These findings suggest that Wistar fatty rats have a poor capacity for proliferation of pancreatic beta-cells, which causes the onset of overt diabetes along with insulin resistance due to extreme obesity.

Animals↗

PubMed1997

Transcriptional activation of the Glut1 gene in response to oxidative stress in L6 myotubes.

Exposure of L6 myotubes to prolonged low grade oxidative stress results in increased Glut1 expression at both the protein and mRNA levels, leading to elevated glucose transport activity. To further understand the cellular mechanisms responsible for this adaptive response, the Glut1 transcription rate and mRNA stability were assessed. Nuclear run-on assays revealed 2.0- and 2.4-fold increases in Glut1 transcription rates in glucose oxidase- and xanthine/xanthine oxidase-pretreated cells, respectively. Glut1 mRNA stability was increased with both treatments compared with the control (t1/2 = 7.8 +/- 1.3, 6.0 +/- 2.0, and 2.4 +/- 0.5 h, respectively). The serum-responsive element and AP-1 (but not the cAMP-responsive element) showed increased binding capacity following oxidative stress. Both activation of AP-1 binding and elevation of Glut1 mRNA were prevented by cycloheximide. The involvement of enhancer 1 of the Glut1 gene was demonstrated using transfected 293 cells. Induction of Glut1 mRNA in response to oxidative stress differed from its activation by chronic insulin exposure as demonstrated by the ability of rapamycin to inhibit the latter without an effect on the former. In conclusion, oxidative stress increases the Glut1 transcription rate by mechanisms that may involve activation of AP-1 binding to enhancer 1 of the Glut1 gene.

Animals↗

PubMed1997

Myocardial ischemia induces differential regulation of KATP channel gene expression in rat hearts.

The cardiac ATP-sensitive potassium (KATP) channel is thought to be a complex composed of an inward rectifier potassium channel (Kir6.1 and/or Kir6.2) subunit and the sulfonylurea receptor (SUR2). This channel is activated during myocardial ischemia and protects the heart from ischemic injury. We examined the transcriptional expression of these genes in rats with myocardial ischemia. 60 min of myocardial regional ischemia followed by 24-72 h, but not 3-6 h, of reperfusion specifically upregulated Kir6.1 mRNA not only in the ischemic (approximately 2.7-3.1-fold) but also in the nonischemic (approximately 2.0-2.6-fold) region of the left ventricle. 24 h of continuous ischemia without reperfusion also induced an increase in Kir6.1 mRNA in both regions, whereas 15-30 min of ischemia followed by 24 h of reperfusion did not induce such expression. In contrast, mRNAs for Kir6.2 and SUR2 remained unchanged under these ischemic procedures. Western blotting demonstrated similar increases in the Kir6.1 protein level both in the ischemic (2.4-fold) and the nonischemic (2.2-fold) region of rat hearts subjected to 60 min of ischemia followed by 24 h of reperfusion. Thus, prolonged myocardial ischemia rather than reperfusion induces delayed and differential regulation of cardiac KATP channel gene expression.

ATP-Binding Cassette Transporters↗

PubMed1997

The placenta is not the main source of leptin production in pregnant rat: gestational profile of leptin in plasma and adipose tissues.

The gestational profiles of leptin in plasma, adipose tissue and placenta were investigated in rats. Leptin in plasma and the adipose tissue of the maternal compartment increased as pregnancy advanced and remained high during the latter half of pregnancy (approximately 2-fold compared with the non-pregnant state), followed by a rapid decrease just before parturition. Leptin in fetal plasma and amniotic fluid was first detectable on day 19 and then increased to levels comparable to those in maternal plasma of non-pregnant and day 21 pregnant rats. The total amount of mRNA in maternal adipose tissues significantly increased as pregnancy advanced and reached about 2.5-fold of those of non-pregnant rats on day 19 of pregnancy, followed by a marked decrease on day 3 of lactation. Placentae and decidual tissues did not show any expression of leptin mRNA on day 12 and 19 of pregnancy. These results indicate that the placenta is not a major source of leptin production in rats and also suggest the physiological significance of leptin in rat pregnancy.

Adipose Tissue↗

PubMed1997

Daily injections of melatonin entrain the circadian activity rhythms of nocturnal rats but not diurnal chipmunks.

It is well known that daily injections of melatonin entrain the free-running rhythms of nocturnal rodents (rats and hamster) and diurnal sauropside (birds and lizard). Here, we asked whether daily injections of melatonin entrain the free-running rhythm of the chipmunk, a diurnal rodent, and, if they do, is the phase relationship between the time of injection and onset of the activity interval similar to that in sauropside rather than that of nocturnal rodents? Contrary to our expectations, daily injections of melatonin did not entrain the free-running rhythm in 9 of 10 chipmunks, even when a high dose of melatonin (1 mg/kg, b.wt.) was used. These results indicate that the entraining effect of daily injections of melatonin on free-running rhythm varies among mammalian species.

Animals↗

PubMed1997

Increase of mouse leptin production by adipose tissue after midpregnancy: gestational profile of serum leptin concentration.

The serum concentration of leptin in 10 week old virgin ICR mice assessed by RIA was 1.70 +/- 0.08 ng/ml. The serum leptin concentration in the pregnant mice mated at 10 weeks of age significantly increased from day 11 of pregnancy and reached a peak on day 17 of pregnancy (42.2 +/- 4.8 ng/ml). AFter the delivery, the serum leptin concentration rapidly decreased and reached the level of the virgin mouse on the seventh day in the puerperium. Tissue contents of leptin in the placenta, the decidua, the uterus, and the adipose tissue were between 40 to 130 ng/g wet tissue. However, leptin mRNA was expressed only in the adipose tissue and the level of leptin mRNA on days 13 and 17 of pregnancy increased 3- to 5-fold compared with that of virgin mouse. Tissue content of leptin in the adipose tissue significantly increased from day 17 of pregnancy compared with that of the virgin mouse. The m-leptin secretion from the adipose tissue also significantly increased in vitro. These results suggest that leptin, which was secreted by adipose tissue, may play important roles in mouse reproduction after midpregnancy.

Adipose Tissue↗

PubMed1997

Individual pineal cells in chick possess photoreceptive, circadian clock and melatonin-synthesizing capacities in vitro.

Chick pineal cells express a circadian rhythm of melatonin release under light-dark (LD) cycles, with an increase during the dark period and a decrease during the light period, and this rhythm persists under constant darkness (DD). We cultured individual single pineal cells with 15 microl of medium per well in a Terasaki plate and measured melatonin secretion every 12 h under LD, DL and DD. Individual cells secreted more melatonin during the dark period than during the light period under both LD and DL conditions, and those rhythmic secretions persisted under DD. These results suggest that individual pineal cells in chick have photoreceptive, circadian clock and melatonin-synthesizing capacities.

Animals↗

PubMed1997

A small molecule CXCR4 inhibitor that blocks T cell line-tropic HIV-1 infection.

Several members of the chemokine receptor family have been shown to function in association with CD4 to permit human immunodeficiency virus type 1 (HIV-1) entry and infection. The CXC chemokine receptor CXCR4/fusin is a receptor for pre-B cell growth stimulating factor (PBSF)/stromal cell-derived factor 1 (SDF-1) and serves as a coreceptor for the entry of T cell line-tropic HIV-1 strains. Thus, the development of CXCR4 antagonists or agonists may be useful in the treatment of HIV-1 infection. T22 ([Tyr5,12,Lys7]-polyphemusin II) is a synthesized peptide that consists of 18 amino acid residues and an analogue of polyphemusin II isolated from the hemocyte debris of American horseshoe crabs (Limulus polyphemus). T22 was found to specifically inhibit the ability of T cell line-tropic HIV-1 to induce cell fusion and infect the cell lines transfected with CXCR4 and CD4 or peripheral blood mononuclear cells. In addition, T22 inhibited Ca2+ mobilization induced by pre-B cell growth stimulating factor (PBSF)/SDF-1 stimulation through CXCR4. Thus, T22 is a small molecule CXCR4 inhibitor that blocks T cell line-tropic HIV-1 entry into target cells.

3T3 Cells↗

PubMed1997

Gender difference in regulation of branched-chain amino acid catabolism.

Regulation of the activity state of the hepatic branched-chain 2-oxo acid dehydrogenase (BCODH) complex during the light-dark cycle differs markedly in male and female rats. Female rats exhibit a profound diurnal rhythm in the activity state of the complex that is not observed in male rats. Regardless of gender, most of the complex was dephosphorylated and active in the middle of the dark period and early in the light period, and this form of the complex predominated in male rats at the end of the light period. In contrast, most of the complex in female rats became phosphorylated and inactive by the end of the light period. Gonadectomy prevented the diurnal rhythm in females but was without effect in males, indicating that female sex hormones are required for this gender difference in regulation of the BCODH complex. Changes in levels of branched-chain 2-oxo acids, known regulators of BCODH kinase, do not seem to be involved; rather, an increase in BCODH kinase activity occurring between morning and evening is responsible for inactivation of the BCODH complex in female rats. The increase in kinase activity is due to an increase in the amount of kinase protein associated with the BCODH complex. Thus a marked diurnal variation in the amount of BCODH kinase and therefore its activity results in large swings in the activity state of the liver BCODH complex in female rats. This study provides the first evidence for a gender-specific difference in the regulation of branched-chain amino acid catabolism.

3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide)↗

PubMed1997

Purification and characterization of the human interleukin-18 receptor.

Interleukin (IL)-18 was identified as a molecule that induces IFN-gamma production and enhances NK cell cytotoxicity. In this paper, we report upon the purification and characterization of human IL-18 receptor (hIL-18R). We selected the Hodgkin's disease cell line, L428, as the most strongly hIL-18R-expressing cell line based on the results of binding assays. This binding was inhibited by IL-18 but not by IL-1beta. The dissociation constant (Kd) of 125I-IL-18 binding to L428 cells was about 18.5 nM, with 18,000 binding sites/cell. After immunizing mice with L428 cells and cloning, a single monoclonal antibody (mAb) against hIL-18R was obtained (mAb 117-10C). Sequentially, hIL-18R was purified from 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonic acid (CHAPS)-extracted L428 cells by wheat germ lectin-Sepharose 4B chromatography and mAb 117-10C-Sepharose chromatography. The internal amino acid sequences of hIL-18R all matched those of human IL-1 receptor-related protein (IL-1Rrp), the ligand of which was unknown to date. When expressed in COS-1 cells, the cDNA of IL-1Rrp conferred IL-18 binding properties on the cells and the capacity for signal transduction. From these results, we conclude that a functional IL-18 receptor component is IL-1Rrp.

Amino Acid Sequence↗

PubMed1997

Laser scanning cytometry allows detection of cell death with morphological features of apoptosis in cells stained with PI.

Laser scanning cytometry (LSC), a newly developed technology, allowed simple detection of dead cells with morphological features of apoptosis for cells stained with only propidium iodide (PI). HeLa cells were treated with Adriamycin (ADM, 0.5 or 1.0 microgram/ml). A PI fluorescence value (representing DNA content) versus PI fluorescence peak (representing chromatin condensation) cytogram of LSC made it possible to segregate cells with high PI fluorescence peak from others in a cell population and concomitantly to analyze the relationship between the cells and the cell cycle. A fraction of the cells manifesting hypercondensation of chromatin was exclusively present in a cell population treated with ADM. Visual inspection of the cells defined in the cytogram revealed morphological features of apoptosis. LSC analysis facilitates monitoring effects of anticancer drugs on a cell population, because nuclear DNA staining with PI is simple and rapid.

Antibiotics, Antineoplastic↗