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Biomedical subjects

M Murakami

Publications and source records attributed to M Murakami.

At least 541 records · Page 30Linked to original sources
PubMed1997

Effects of the new angiotensin receptor antagonist dipotassium (Z)-2-[[5-ethyl-3-[2'-(1H-tetrazol-5-yl)biphenyl-4-yl] methyl-1,3,4-thiadiazoline-2-ylidene]aminocarbonyl]-1-cy clopentencarbox ylate on experimental cardiac hypertrophy and acute left ventricular failure.

The cardiovascular effects of dipotassium (Z)-2-[[5-ethyl-3-[2'-(1H-tetrazol-5-yl)biphenyl-4-yl] methyl-1,3,4-thiadiazoline-2-ylidene]aminocarbonyl]-1-cyc lopentencarboxylate CAS 169328-25-0, KRH-594), a new angiotensin II type 1 (AT1) receptor antagonist, on pressure-overload cardiac hypertrophy in rats and on acute left ventricular failure in dogs were investigated. In rats with a 2-week abdominal aorta constriction, left ventricular weight (LVW) and systolic blood pressure (SBP) were significantly greater than in sham-operated rats. Oral administration of KRH-594 (10 or 30 mg/kg/day for 2 weeks) reduced the increases in both LVW and SBP. Another AT1 receptor antagonist, candesartan cilexetil (1 or 3 mg/kg/day for 2 weeks), also prevented this type of cardiac hypertrophy. In anesthetized dogs with a 60-min coronary ligation, left ventricular end-diastolic pressure (LVEDP) and total peripheral resistance (TPR) were raised, whereas the maximum first derivative of left ventricular pressure and cardiac output were both decreased. Intravenous administration of KRH-594 (3 mg/kg) significantly attenuated the increases in both LVEDP and TPR after coronary ligation. These results suggest that KRH-594, by reducing the cardiac afterload, may ameliorate pressure-overload cardiac hypertrophy in rats and produce an improvement in the hemodynamic status of dogs with acute left ventricular failure.

Acute Disease↗
PubMed1997

Coronary to bronchial artery anastomosis in patients with noncyanotic cardiopulmonary disease: report of seven cases.

An angiographically visible coronary to bronchial artery anastomosis was found in seven (0.12%) of 6045 patients with noncyanotic cardiopulmonary disease who underwent coronary angiography between 1989 and 1995. Aortitis syndrome was associated with four patients, whereas pulmonary embolism, aortic regurgitation and vasospastic angina were the diagnoses in the others. Coronary stenotic lesions were not observed in any patients. In five of six patients who underwent pulmonary perfusion scintigraphy, perfusion defect was observed in the area supplied by the bronchial artery, which had the anastomosis to the coronary artery. In each patient this anastomosis seemed to function as collateral circulation, compensating for decreased perfusion in either the lung or the heart. When coronary to bronchial artery anastomosis is found, ischemic conditions in either the lung or the heart are likely.

Angina Pectoris↗
PubMed1997

[Prognosis of hepatic metastasis from colorectal cancer following hepatic resection and arterial infusion chemotherapy--assessment from the percentage of tumor involved area].

Prognosis of hepatic metastasis from colorectal cancer following hepatic resection and arterial infusion chemotherapy was studied from the percentage of tumor involved area (PTIA). The PTIA was calculated by the following formula: sigma S'/sigma S, with S' as the tumor area and S as the liver area on each CT slice. The subjects were 25 cases of hepatic resection (HR), and 31 cases of hepatic arterial infusion chemotherapy (HAI). The PTIA of the cases of HR and that of HAI was 1.5 to 25.9% and 0.8 to 31.3%, respectively. For comparison, all cases were divided into group A, which was not more than 10% of the PTIA, and group B, which was more than 10% of the PTIA. In the cases of HR, the prognosis of group A was significantly better than that of group B (p < 0.05). In the cases of HAI, the prognosis of group A was better than that of group B. Even in group A, the prognosis of the cases of HR was significantly better than that of HAI (p < 0.05). These results suggest that the PTIA in the cases of HR and HAI for metastasis from colorectal cancer is important factor which reflects the prognosis.

Colorectal Neoplasms↗
PubMed1997

[A case of lung carcinoid].

A 78-year-old female was pointed out an abnormal shadow in left lung field. For 4 years this shadow was followed up as benign tumor. Chest CT scan revealed growing tumor and new tumor in right lung. Tumor resection was performed. Until operation time carcinoid syndrome was not found. This case was diagnosed histopathologically typical carcinoid of peripheral lung.

Aged↗
PubMed1997

[HLA-DQ region and TCR gene polymorphism associated with primary IgA nephropathy in Japanese children].

We have investigated associations between HLA-DQ beta and TCRC beta gene polymorphisms and IgA nephropathy in Japanese children. DNA from 33 cases of IgA nephropathy, 29 cases of nephrotic syndrome and 29 cases of healthy volunteers were analyzed by Southern blotting using HLA-DQ beta and TCRC beta probes. A 2 kb (Taq I) polymorphic band that hybridized to the DQ beta probe was predominant in patients of IgA nephropathy (p < 0.05) compared to the controls. The 10 kb (Bgl II) polymorphic band of TCRC beta was also predominantly present (but not significantly) in the DNA of these patients. Proteinuria in IgA nephropathy patients was found to be associated with this 10 kb TCR polymorphism. We conclude that the HLA-DQ beta and TCR genes make major contributions to the genetic pathogenesis of IgA nephropathy in Japanese children.

Adolescent↗
PubMed1997

Role of angiotensin II generated by angiotensin converting enzyme-independent pathways in canine kidney.

Recent studies have provided evidence of angiotensin converting enzyme (ACE)-independent angiotensin (Ang) II formation in tissue renin-angiotensin systems. We studied the effects of Ang II generated by ACE-independent pathways on renal hemodynamics. We used a synthetic peptide, [Pro11, D-Ala12]-Ang I (S), which yields Ang II by chymase, but not by ACE. Infusion of Ang I into a renal artery caused a decrease in renal blood flow, and reciprocally an increase in mean arterial pressure. Infusion of S (1 nmol/kg) caused a decrease in renal blood flow (-20%), but a larger dose was needed to increase mean arterial pressure. Studies with an intravital needle-probe CCD camera revealed that the Ang I infusion induced dose-dependent vasoconstriction of afferent and efferent arterioles (49% and 54%, respectively at 1 nmol/kg). In contrast, infusion of S elicited only 30% constriction of these vessels at a dose of 1 nmol/kg and induced no further constriction at higher doses, indicating that different segments of renal vessels responded in different fashions to Ang II formed via ACE-independent pathways. These vasoconstrictions were abolished by an angiotensin II receptor (AT-1) antagonist. Enzymatic assays using reverse-phase HPLC revealed that the ACE-dependent pathway was predominant in the rena1 cortex (approximately 80%). We also determined Ang II concentrations in renal cortex specimens obtained by needle biopsy. Intrarenal S infusion (10 nmol/kg) increased plasma and renal Ang II concentrations to 160% and 710% of the respective baseline levels. This study provides in vivo evidence of ACE-independent Ang II formation in renal tissue and suggests that this locally-formed Ang II influences the renal circulation in a paracrine fashion.

Angiotensin II↗
PubMed1997

Effects of alpha-phenyl N-tert-butylnitrone, a spin trap reagent, on the proliferation of murine hematopoietic progenitor cells in vitro.

We investigated the effect of alpha-phenyl N-tert-butylnitrone (PBN), a spin trap reagent, on the proliferation of murine hematopoietic progenitor cells in vitro. During the addition of PBN to the liquid cultures of murine bone marrow cells containing a combination of interleukin-3, interleukin-6 and the c-kit ligand/stem cell factor, colony-forming cells in vitro (CFC) and the colony-forming unit in the spleen (CFU-S) increased about 1.6-fold and 2.0-fold, respectively, higher than the control culture. These effects were not observed when using dimethyl sulfoxide, which has the ability to scavenge radicals, and 5,5-dimethyl-1-pyrroline N-oxide, another spin trap reagent. Analysis of cultured cells from a 7-day liquid culture with PBN revealed that the ratio of the intracellular glutathione (GSH) and GSH/GSSG (oxidized GSH) content was higher than the control. Adding thiol N-acetylcysteine, a thiol reagent and a precursor of intracellular GSH, also showed similar effects on the liquid culture of murine hematopoietic progenitor cells and the level of intracellular GSH. In contrast, adding DL-buthionine-[S,R]-sulfoximine, a gamma-glutamylcysteine synthetase inhibitor, decreased the intracellular GSH level and did not increase the number of CFC and CFU-S. These results suggest that PBN regulates the content of intracellular thiol molecules, and the possibility of a relationship between the intracellular redox state and the proliferation and differentiation of hematopoietic stem cells.

Acetylcysteine↗
PubMed1997

[Intraocular neovascularization].

To investigate the mechanism of intraocular neovascularization, we studied how vascular endothelial growth factor (VEGF) and interleukin-8 (IL-8) are expressed in the ocular tissues under hypoxic conditions. Prior to proliferation of vascular endothelial cells resulting in neovascularization, the retinal tissues such as pericytes, retinal glial cells, ganglion cells, and ciliary epithelium react directly to hypoxia expressing VEGF and/or IL-8 and stimulate endothelial cell proliferation in a paracrine manner. We demonstrated that transcription factor activator protein-1 (AP-1) is activated for expression of VEGF messenger ribonuculeic acid (mRNA) and in a similar way nuclear factor kappa B (NF-kappa B) is activated for expression of IL-8 mRNA. However, hypoxia-induced expression of VEGF and/ or IL-8 is only one aspect of the complicated processes in intraocular neovascularization. We hope that further detailed analysis of the mechanism will make it possible to inhibit and treat clinically intraocular neovascularization in the near future.

Adult↗
PubMed1997

Effects of intravenous lipoprostaglandin E1 on neurogenic intermittent claudication.

Circulation disturbances in the cauda equina and nerve roots have been implicated in the genesis of neurogenic intermittent claudication (NIC) in patients with lumbar spinal stenosis (LSS). We report the clinical results of lipoprostaglandin E1 (lipo-PGE1) treatments in patients with NIC. Lipo-PGE1 was administered intravenously for 10 consecutive days to 40 patients, 31 of whom showed a response to the treatment. Of the clinical symptoms examined, walking ability and leg numbness were significantly improved with an average effective period of 2.5 months. However, patients with radicular pain and severely affected patients did not respond well. Nerve root circulation in eight patients who subsequently underwent surgery was measured with a laser Doppler flowmeter. We observed increased blood flow in seven of these eight patients, after the intraoperative administration of lipo-PGE1. Lipo-PGE1 produced symptomatic improvement for a limited period in the treatment of NIC associated with LSS. The drug appeared to exert its effects through an increase in the circulation of blood in the nerve roots and the cauda equina.

Adult↗
PubMed1997

Lansoprazole elevates the ratio of serum pepsinogen I v.s. pepsinogen II.

In order to investigate the mechanism by which proton pump inhibitor increases serum pepsinogen levels, we evaluated the effects of ulcer location and IgG antibody against Helicobacter pylori on lansoprazole-induced elevations. Patients with endoscopically proven peptic ulcer received lansoprazole 30 mg/day for 6 or 8 weeks; pepsinogen I and II levels, along with antibody to H. pylori, were measured in fasting blood samples. We found that whether or not antibody to H. pylori was present, pepsinogen I and II levels and the I/II ratio rose significantly in lansoprazole-treated patients. Patients with stomach-body ulcers showed smaller increases in both pepsinogens than did those with ulcers in the gastric angle/antrum or in the duodenum. In conclusion, lansoprazole increases serum levels of both pepsinogens I and II, although a larger increase in pepsinogen I elevates the pepsinogen I/II ratio. The relatively small increases seen in patients with stomach-body ulcers suggest atrophic changes in the gastric mucosa in patients with stomach-body ulcer.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1996

Type II phospholipase A2 is linked to cyclooxygenase-2-mediated delayed prostaglandin D2 generation by cultured mouse mast cells following FcepsilonRI- and cytokine-dependent activation.

Treatment of murine bone marrow-derived mast cells (BMMC) with interleukin (IL)-10 and IL-1beta increased the expression of type II secretory phospholipase A2 (sPLA2), but not cytosolic PLA2 (cPLA2), after culture for several hours. Further stimulation with IgE and antigen (IgE/Ag) increased cyclooxygenase (COX)-2 expression dramatically, accompanied by augmented delayed prostaglandin (PG) D2 generation over several hours. BMMC were also found to express type IIC PLA2 (PLA2-IIC), a recently described novel sPLA2 possessing 16 cysteine residues, expression of which changed minimally after BMMC activation. Delayed PGD2 generation was suppressed by approximately 80% by an antibody raised against recombinant murine type II sPLA2. These results suggest that, of the three PLA2s expressed in BMMC, type II sPLA2 is the critical enzyme that is coupled with COX-2-dependent PGD2 generation elicited by IgE/Ag in the presence of IL-10 + IL-1beta.

Animals↗
PubMed1996

Antimutagenicity of Tochu tea (an aqueous extract of Eucommia ulmoides leaves): 2. Suppressing effect of Tochu tea on the urine mutagenicity after ingestion of raw fish and cooked beef.

The effect of Tochu tea, which is an aqueous extract of Eucommia ulmoides leaves and a popular-beverage in Japan, on the urine mutagenicity before and after ingestion of raw fish and cooked beef was studied using Salmonella typhimurium YG1024. Urines were collected from seven healthy, non-smoking Japanese women before and after ingestion of raw fish and cooked beef. In experiment 1,3 were in a control group and 4 were in a Tochu tea-drinking group (2000 ml per day). The mutagenicity of urine from the Tochu tea-drinking group was much lower. In experiment 2 the 7 women switched groups; the tea-drinking group became the control group, and the control group became the Tochu tea-drinking group. Again, the mutagenicity of urine collected from the Tochu tea-drinking group was much lower. These results suggest that the decrease in the mutagenicity of the urine from the Tochu tea-drinking group was due to the intake of Tochu tea, but not to individual differences. Thus, the ingestion of Tochu tea may reduce human exposure to dietary mutagens.

Adult↗
PubMed1996

Cross-linking of the high-affinity IgE receptor induces the expression of cyclo-oxygenase 2 and attendant prostaglandin generation requiring interleukin 10 and interleukin 1 beta in mouse cultured mast cells.

When mouse bone marrow-derived mast cells (BMMC) developed in interleukin (IL)-3 were activated with IgE and antigen (IgE/antigen) in the presence of both IL-10 and IL-1 beta, two sequential phases of prostaglandin (PG)D2 generation were elicited, in which the first phase occurred by 1 h and the second phase from 2 to 10 h. The delayed phase of PGD2 generation was accompanied by a marked induction of cyclo-oxygenase (COX)-2 mRNA, which reached a peak at 1-2 h, followed by that of its protein from 2-10 h, with a peak at 5 h. The immediate phase of PGD2 generation was completely abrogated by the irreversible inhibition of pre-existing COX-1 by aspirin pretreatment, whereas the delayed phase of PGD2 generation was almost undetectable in the presence of the COX-2 inhibitor NS-398. A detailed analysis of the individual effects of IgE/antigen, IL-10 and IL-1 beta on COX-2 expression revealed that IgE/antigen and IL-10 each initiated and stabilized COX-2 mRNA expression, leading to an increase in the expression of its protein. Conversely, IL-1 beta stabilized the COX-2 protein without affecting its mRNA level. The induction of COX-2 by IgE/antigen with IL-10 and IL-1 beta preceded the induction of transcripts for endogenous cytokines such as IL-6, IL-1 beta and IL-10. The inhibition of PGD2 generation by indomethacin did not affect the induction of COX-2 or these cytokines. Thus the two major delayed-phase responses of BMMC after IgE-dependent activation, namely COX-2-dependent PGD2 generation and cytokine production, are regulated independently.

Animals↗
PubMed1996

Type II secretory phospholipase A2 associated with cell surfaces via C-terminal heparin-binding lysine residues augments stimulus-initiated delayed prostaglandin generation.

Type II secretory phospholipase A2 (sPLA2) has been shown to be induced by a variety of proinflammatory stimuli and, therefore, has been implicated in the inflammatory process. In order to determine whether association of sPLA2 with cell surfaces via heparan sulfate proteoglycan is important for its effects on cellular functions, we have identified the critical domain in sPLA2 for heparin and cell surface binding and examined its role in cellular prostaglandin (PG) biosynthesis. Replacement of several conserved Lys residues in the C-terminal region of mouse and rat sPLA2s by Glu resulted in a marked reduction of their capacities to bind to heparin and mammalian cell surfaces without affecting their enzymatic activities toward dispersed phospholipid as a substrate. CHO cells stably transfected with wild-type sPLA2 released about twice as much arachidonic acid (AA) during culture for 10 h with fetal calf serum and interleukin-1beta than cells transfected with vector alone, whereas the ability to enhance AA release was impaired in sPLA2 mutants incapable of binding to cell surfaces. AA released by wild-type sPLA2-transfected CHO cells was metabolized to prostaglandin E2 via prostaglandin endoperoxide H synthase (PGHS)-2 after IL-1beta stimulation, revealing a particular functional linkage of sPLA2 to PGHS-2. In contrast, A23187-initiated immediate AA release over 30 min was not affected by sPLA2 overexpression. Taken together, these results suggest that sPLA2 expressed endogenously and anchored on cell surfaces via its C-terminal heparin-binding domain is involved in the PGHS-2-dependent delayed PG biosynthesis initiated by growth factors and cytokines during long term culture.

Amino Acid Sequence↗
PubMed1996

Thymic hyperplasia in patients with Graves' disease. Identification of thyrotropin receptors in human thymus.

Thymic size and density were studied in 23 untreated patients with Graves' disease and 38 control subjects using computed tomography. Both thymic size and density were higher in untreated patients with Graves' disease than in control subjects in the age-matched group. After treatment with antithyroid drugs, both thymic size and density were significantly reduced, with a concomitant decrease in thyrotropin receptor antibodies. PCR of human thymic cDNA using primers for human thyrotropin receptor amplified a fragment in a size expected for the receptor, and its nucleotide sequence was identical to human thyrotropin receptor cDNA in the thyroid. Northern blot analysis of human thymic poly(A)+ RNA demonstrated the presence of the full length form of thyrotropin receptor mRNA. Western blot analysis of human thymic membrane using anti-thyrotropin receptor peptide antibodies demonstrated a band of 100 kD that was also observed in the thyroid membrane. Immunohistochemistry of thymic tissue using mouse antihuman thyrotropin receptor monoclonal antibodies demonstrated the immunostaining of epithelial cells. These results indicate that thymic hyperplasia is apparently associated with Graves' disease and suggest that thymic thyrotropin receptor may act as an autoantigen that may be involved in the pathophysiology of development of Graves' disease.

Adult↗
PubMed1996

A mammalian capacitative calcium entry channel homologous to Drosophila TRP and TRPL.

Intracellular Ca2+ signalling evoked by Ca2+ mobilizing agonists, like angiotensin II in the adrenal gland, involves the activation of inositol(1,4,5)trisphosphate(InsP3)-mediated Ca2+ release from internal stores followed by activation of a Ca2+ influx termed capacitative calcium entry. Here we report the amino acid sequence of a functional capacitative Ca2+ entry (CCE) channel that supports inward Ca2+ currents in the range of the cell resting potential. The expressed CCE channel opens upon depletion of Ca2+ stores by InsP3 or thapsigargin, suggesting that the newly identified channel supports the CCE coupled to InsP3 signalling.

Amino Acid Sequence↗