[Show abstract][Hide abstract] ABSTRACT: Chronic inhibition of NO synthesis induces cardiac hypertrophy independent of systemic blood pressure (SBP) by increasing protein synthesis in vivo. We examined whether ACE inhibitors (ACEIs) enalapril and temocapril and angiotensin II type-I receptor antagonists (angiotensin receptor blockers [ARBs]) losartan and CS-866 can block cardiac hypertrophy and whether changes in activation of 70-kDa S6 kinase (p70S6K) or extracellular signal-regulated protein kinase (ERK) are involved. The following 13 groups were studied: untreated Wistar-Kyoto rats and rats treated with NO synthase inhibitor Nomega-nitro-L-arginine methyl ester (L-NAME), D-NAME (the inactive isomer of L-NAME), L-NAME plus hydralazine, L-NAME plus enalapril (3 mg. kg(-1). d(-1)) or temocapril (1 or 10 mg. kg(-1). d(-1)), L-NAME plus losartan (10 mg. kg(-1). d(-1)) or CS-866 (1 or 10 mg. kg(-1). d(-1)), L-NAME plus temocapril-CS866 in combination (1 or 10 mg. kg(-1). d(-1)), and L-NAME plus rapamycin (0.5 mg. kg(-1). d(-1)). After 8 weeks of each experiment, ratios of coronary wall to lumen (wall/lumen) and left ventricular weight to body weight (LVW/BW) were quantified. L-NAME increased SBP, wall/lumen, and LVW/BW compared with that of control. ACEIs, ARBs, and hydralazine equally canceled the increase in SBP induced by L-NAME. However, ACEIs and ARBs equally (but not hydralazine) attenuated increase in wall/lumen and LVW/BW induced by L-NAME. The L-NAME group showed both p70S6K and ERK activation in myocardium (2.2-fold and 1.8-fold versus control, respectively). ACEIs inactivated p70S6K and ARBs inactivated ERK in myocardium, but hydralazine did not change activation of either kinase. Thus, ACEIs and ARBs modulate different intracellular signaling pathways, inhibiting p70S6K or ERK, respectively, to elicit equal reduction of cardiac hypertrophy induced by chronic inhibition of NO synthesis in vivo.
[Show abstract][Hide abstract] ABSTRACT: In addition to advanced stenosis, earlier stages of carotid atherosclerosis are associated with the risk for stroke. However, the significance has not been established for specific stroke subtypes. This study examines the association of earlier carotid atherosclerosis with stroke subtypes.
The subjects comprised 1059 patients (mean+/-SD age, 62+/-11 years) with <60% carotid stenosis. With the use of ultrasound, carotid atherosclerosis was evaluated by the plaque score, as defined by the sum of all plaque heights in bilateral carotid arteries. On the basis of neurological signs and symptoms, medical history, and brain MRI, we diagnosed stroke and its subtypes as follows: no stroke (n=738), atherothrombotic infarction (AI) (n=56), lacunar infarction (LI) (n=117), cardioembolic infarction (n=65), cerebral hemorrhage (n=26), and other or unclassified stroke (n=57).
The plaque score was higher in AI (10.5+/-5.9) and LI (6.0+/-5.1) groups than in the no-stroke group (4.3+/-4.9) (both P<0.05), although it was similar between other stroke groups and the no-stroke group. Each 1 SD greater plaque score was associated with 2.5-fold (95% CI, 2.0 to 3.2) higher risk for AI and 1.4-fold (95% CI, 1.2 to 1.7) higher risk for LI compared with the no-stroke group. When we adjusted for cardiovascular risk factors, plaque score remained significantly associated with AI but not with LI. By receiver operating characteristic curve analyses, the receiver operating characteristic area for AI (0.81 to 0.86) was greater than that for LI (0.62 to 0.67) when we used plaque score either alone or in combination with cardiovascular risk factors.
Although evaluation of carotid atherosclerosis may aid in the risk assessment for AI and LI, the benefit appears to be greater for AI.
[Show abstract][Hide abstract] ABSTRACT: Recently, there has been great interest in adult neurogenesis. We investigated whether transient forebrain ischemia could influence the proliferation of neuronal progenitor in the subgranular zone (SGZ) of the rat hippocampus and whether aging could influence the neurogenesis after ischemia.
Male Wistar rats were subjected to 4-vessel occlusion model. We used a bromodeoxyuridine (BrdU) labeling method to identify the postproliferation cells and double-immunostaining with confocal microscopy to determine the cell phenotype.
The number of BrdU-positive cells in the SGZ increased approximately 5.7-fold 8 days after ischemia, compared with the control. BrdU-positive cells formed clusters, which suggested that these cells had divided from an original progenitor cell, and expressed Musashi1 (Msi1), a marker of neural stem/progenitor cells. Although astrocytes also expressed Msi1 in the adult brain, Msi1-positive cells that formed clusters in the SGZ did not express glial fibrillary acidic protein, an astrocyte marker. About 70% of all BrdU-positive cells in the SGZ represented the neuronal phenotype 4 weeks after the BrdU injection. Although proliferation of progenitor cells was stimulated in both young and older animals, aging accelerated the reduction in newborn cells after ischemia.
Our results indicate that ischemic stress stimulated the proliferation of neuronal progenitor cells in the SGZ of both young and old rats but resulted in increased neurogenesis only in young animals. Our findings will be important in developing therapeutic intervention to enhance endogenous neurogenesis after brain injury.
[Show abstract][Hide abstract] ABSTRACT: OBJECTIVE: The purpose of this study was to identify helical CT and MR imaging features of pancreatic masses (focal enlargement) due to chronic pancreatitis and their correlation with pathologic findings. CONCLUSION: When histologic fibrosis is uniformly present through the pancreas in patients with chronic pancreatitis, there is no demarcation of masses due to chronic pancreatitis. When there is a greater degree of histologic fibrosis in the masslike part of the pancreas, the mass is often demarcated from the remaining pancreas, and the enhancement pattern on two-phase helical CT and dynamic gadolinium-enhanced MR imaging mimics that of pancreatic adenocarcinoma.
No preview · Article · Sep 2001 · American Journal of Roentgenology
[Show abstract][Hide abstract] ABSTRACT: Experimental results for the thermal conductivity of ammonia, propane, butane, isobutane, and propylene are reviewed, with special attention given to the liquid phase. New equations for the thermal conductivity of these five substances applicable for practical use over wide ranges of temperature and pressure including the critical region are proposed based on the experimental data. The present equations as well as the existing equations are compared with the experimental data. Compared with existing equations for ammonia, isobutane, and propylene, which are not reliable in the liquid phase, the behavior of the thermal conductivity for these substances is much improved using the present equations.
No preview · Article · Sep 2001 · International Journal of Thermophysics
[Show abstract][Hide abstract] ABSTRACT: The onset of acute myocardial infarction (AMI) shows characteristic circadian variations; that is, a definite morning peak related to biologic rhythms and a vague nighttime peak related to socioeconomic factors. The recent economic recession in Japan may change the circadian variation, especially the nighttime peak. This study evaluated the recent circadian variation of AMI in Osaka and specified the patient subgroups showing either a morning or nighttime peak predominantly. Of 1,609 consecutive patients with AMI registered from April 1998 to January 2000, 1,252 whose onset of AMI was definitely identified were studied. The day was divided into six 4-h periods with a morning peak between 08.01 h and 12.00h, and nighttime peak between 20.01 h and 24.00h. When subgroup analysis was performed, female patients aged 65 years or more showed a morning peak alone and male patients aged less than 65 years with an occupation and the habits of cigarette smoking and alcohol intake showed a nighttime peak alone. Thus, in Osaka nighttime socioeconomic factors may currently be more potent triggers of AMI than the morning surges in younger male workers who smoke and drink.
No preview · Article · Aug 2001 · Japanese Circulation Journal
[Show abstract][Hide abstract] ABSTRACT: BACKGROUND: Phosphodiesterase III inhibitors (PDEIII-Is) improve the hemodynamic status of heart failure via inotropic/vasodilatory effects attributable to the increase in intracellular cAMP level. Direct cardioprotection by PDEIII-Is and its underlying mechanisms, however, have not been identified. We tested the infarct size-limiting effect of PDEIII-Is and the roles of cAMP, protein kinase (PK) A, PKC, and mitogen-activated protein kinase (MAPK) families in open-chest dogs. Methods and Results-- Milrinone, olprinone (PDEIII-Is), or dibutyryl-cAMP (db-cAMP) was injected intravenously 30 minutes before 90-minute ischemia, followed by 6 hours of reperfusion. Olprinone was also examined with an intracoronary cotreatment with a PKA inhibitor (H89), a PKC inhibitor (GF109203X), an extracellular signal-regulated kinase kinase (MEK) inhibitor (PD98059), or a p38 MAPK inhibitor (SB203580) throughout the preischemic period. Either PDEIII-Is or db-cAMP caused substantial hemodynamic changes, which returned to control levels in 30 minutes. Collateral flow and percent risk area were identical for all groups. Both PDEIII-Is and db-cAMP increased myocardial p38 MAPK activity during the preischemic period, which was blocked by H89, but not by GF109203X. Both PDEIII-Is and db-cAMP reduced infarct size (19.1+/-4.1%, 17.5+/-3.3%, and 20.3+/-4.8%, respectively, versus 36.1+/-6.2% control, P<0.05 each). Furthermore, the effect of olprinone was blunted by either H89 (35.5+/-6.4%) or SB203580 (32.6+/-5.9%), but not by GF109203X or PD98059. H89, GF109203X, PD98059, or SB203580 alone did not influence infarct size. CONCLUSIONS: Pretreatment with PDEIII-Is has cardioprotective effects via cAMP-, PKA-, and p38 MAPK-dependent but PKC-independent mechanisms in canine hearts.
[Show abstract][Hide abstract] ABSTRACT: Pathogenesis of ischemia/reperfusion injury involves Ca(2+) -induced cell injury. Elevated intracellular Ca(2+) concentration at the reperfusion activates the Ca(2+) dependent protease, calpain and increases the generation of reactive oxygen species (ROS) in mitochondria, which cause cell injury in ischemia/reperfusion.
No preview · Article · Jul 2001 · Clinical calcium
[Show abstract][Hide abstract] ABSTRACT: An elevated plasma concentration of high-sensitivity C-reactive protein (hs-CRP) is a strong predictor of cardiovascular events. However, there have been no longitudinal studies of the relations between development of atherosclerotic lesions and hs-CRP concentrations. Furthermore, it remains unknown whether increased hs-CRP concentrations result in the development of atherosclerosis.
The study included 179 outpatients 40 to 79 years of age who were treated at our institute for traditional risk factors for cardiovascular disease. The patients had no evidence of advanced carotid atherosclerosis at the time of baseline examination. Patients underwent repeated ultrasonographic evaluation of the carotid arteries for 35+/-10 months. Blood samples were collected for hs-CRP measurements. Based on focal intima-media thickening >/=1.1 mm representing plaque, plaque number (PN) and plaque score (PS; the sum of all plaque thicknesses) were calculated. The development of atherosclerosis was estimated by the formula Deltavalue/year=(last value-baseline value)/number of follow-up years. Multivariate linear regression analysis revealed that the log-transformed value for hs-CRP concentration was not related to baseline PN or PS but was related to DeltaPN/year and DeltaPS/year (beta=0.29 and 0.30; P<0.001 for both) independently of the effect of traditional risk factors.
During the early stages of carotid atherosclerosis, the hs-CRP concentration is a marker of carotid atherosclerotic activity rather than extent of atherosclerosis.
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to clarify the immunological and virological responses to pre-administration of interferon-gamma prior to initiation of interferon-alpha treatment in patients with refractory chronic hepatitis C. Twenty-two nonresponders to 6-months of IFN-alpha treatment were enrolled. The hepatitis C virus (HCV) genotype was Ib in all. Natural IFN-gamma (1 MIU/day) was administered daily for 14 days followed by natural IFN-alpha (5 MIU/day) daily for 14 days and then three times weekly for 22 weeks. Serum immunological parameters (IL-10, neopterin, BMG, sCD8, sCD4, IL-6, IL-12) were measured as were the levels of several cytokines (IFN-gamma, TNF-alpha, IL-2, IL-4, IL-5, IL-6, IL-10). Three patients dropped out; two because of the occurrence of other diseases and one because of an adverse effect. At the end of the period of IFN-alpha treatment, HCV-RNA had become negative in six of 19 patients (end-of treatment response; ETR). Six months after the completion of IFN administration, a virological sustained response (SR) was seen in two of 19 patients. The mean serum levels of IL-10 were significantly decreased 6 weeks after the start of treatment. Other immunological parameter levels increased significantly during the period of IFN-gamma administration, and tended to return to the pretreatment level after the start of IFN-alpha administration. Univariate logistic regression analysis showed that the initial change in the levels of these parameters or the change in the ratios of Th1/Th2 parameter levels are useful factors indicative of the end of the treatment response. These findings suggest that priming with IFN-gamma prior to the initiation of IFN-alpha treatment in patients with refractory chronic hepatitis C can modulate the host immune response and this might contribute to viral clearance.
No preview · Article · Jun 2001 · Journal of Viral Hepatitis
[Show abstract][Hide abstract] ABSTRACT: Electroporation has been applied to introducing DNA into several organs; however, gene expression was localized around the injected area. Examined was the efficiency of intrarenal injection of DNA followed by in vivo electroporation, using FITC-labeled oligodeoxynucleotides (FITC-ODN) and plasmid DNA expressing beta-galactosidase or luciferase. FITC-ODN or expression vectors were injected into the left renal artery; thereafter, the left kidney was electroporated between a pair of tweezer-type electrodes. FITC-ODN were transferred into all glomeruli, and transfected cells were identified as mesangial cells. Four d after transfection of the pCAGGS-LacZ gene, beta-galactosidase expression was observed in 75% of glomeruli. To compare the transfection efficacy by electroporation with that by the hemagglutinating virus of Japan (HVJ) liposome method, a luciferase reporter gene, pActLuc, was transferred into glomeruli by either electroporation or the HVJ liposome method. On day 4, electroporation resulted in higher glomerular luciferase activity than did the HVJ liposome method. We also observed that co-transfection of pcEBNA, an expression vector for Epstein-Barr virus nuclear antigen, and poriP-cLuc, oriP-harboring vector, resulted in an eightfold higher luciferase gene expression than simple poriP-cLUC: No histologic damages were seen in glomeruli or tubular epithelial cells. In conclusion, gene transfer into renal artery followed by electroporation was an effective and simple strategy for gene transfer that targets glomerular mesangial cells.
No preview · Article · Jun 2001 · Journal of the American Society of Nephrology
[Show abstract][Hide abstract] ABSTRACT: Microarray is a method that allows the analysis of a large number of genes at the same time. We applied this method to show the difference of gene expression in the kidney caused by proteinuria.
An experimental mouse model of protein overload was prepared by bovine serum albumin injection. The mRNAs of kidneys isolated after 0, 1, 2, 3 and 4 weeks loading were analysed by Northern blotting. We analysed about 18000 genes by microarray. The expression patterns of the microarray were displayed on control, 1 and 3 weeks of protein overload using the clustering procedure. A clone showing the greatest changes of up-regulation in the kidney was cloned and analysed by in situ hybridization and immunohistochemistry.
Over 1600 kinds of gene expression were confirmed in control kidneys. Proteinuria caused systematic changes of gene expression demonstrated by the cluster analysis. The up-regulation of osteopontin mRNA was shown and confirmed by Northern blot analysis. One of the clones showing the largest changes, AA275245, was isolated and characterized. It revealed that AA275245 was an unreported 3' non-coding region of vinculin mRNA which was associated with cytoskeleton proteins (e.g. alpha-actinin, talin, F-actin). Immunohistochemistry and in situ hybridization showed that this clone was identified in glomeruli as a mesangial pattern. The detected signal intensity using both methods, however, was virtually identical in control and disease kidney models. All data including images and analysed signal intensities are accessible on the web site.
The microarray analysis revealed that the renal gene expression pattern was changed dynamically in mice with experimentally induced proteinuria within a few weeks.
No preview · Article · Jun 2001 · Nephrology Dialysis Transplantation
[Show abstract][Hide abstract] ABSTRACT: The purpose of our study was to compare observer performances for the diagnosis of choledocholithiasis using MR cholangiography with volume-rendered, maximum-intensity-projection, and thick-section half-Fourier rapid acquisition with relaxation enhancement sequences.
The images from three types of MR cholangiography performed on 43 patients with biliary calculi were retrospectively analyzed. Image review was conducted for two anatomic compartments (upper biliary tract and common bile duct). A total of 86 compartments, including 19 with bile duct calculi, were reviewed by three independent off-site gastrointestinal radiologists. Observer performance was determined by receiver operating characteristic curve analysis. Image quality was subjectively judged by three radiologists.
Sensitivity was higher with volume-rendered MR cholangiography (58%) than with thick-section (54%, not significant) and maximum-intensity-projection MR cholangiography (47%, p < 0.07). Specificity was higher with volume-rendered MR cholangiography (92%) than with thick-section (86%, p < 0.03) and maximum-intensity-projection MR cholangiography (88%, not significant). Accuracy was higher with volume-rendered MR cholangiography (84%) than with thick-section and maximum-intensity-projection MR cholangiography (79% for both, not significant). Observer performance with volume-rendered MR cholangiography (A(z) = 0.791--0.952) was better than that with thick-section (A(z) = 0.722--0.834) and maximum-intensity-projection MR cholangiography (A(z) = 0.771--0.887). Image quality was better with maximum-intensity-projection MR cholangiography and thick-section MR cholangiography than with volume-rendered MR cholangiography (p < 0.0001).
Observer performance with volume-rendered MR cholangiography was better than that with maximum-intensity-projection and thick-section MR cholangiography for the diagnosis of choledocholithiasis. Volume rendering may be an efficient technique for the reconstruction of MR cholangiography.
No preview · Article · May 2001 · American Journal of Roentgenology
[Show abstract][Hide abstract] ABSTRACT: The present paper reviews current concepts on the role of cyclooxygenase (COX) in the development of malignant tumors. An inducible isoform of cyclooxygenase is expressed in neoplastic, pre-neoplastic, and peri-neoplastic cells by mutation of oncogenes (such as ras), tumor promoters, mitogens, cytokines, their receptors, and pathogenic factors such as Helicobacter. Cells overexpressing cox-2 escape apoptosis, have abnormal cell-to-cell interactions, and acquire invasive phenotypes. On the other hand, angiogenesis plays a key role in the development of malignant tumors. Both in vitro and in vivo studies indicate that cox-2 overexpression upregulates angiogenic factors in neoplastic cells and promotes tumor angiogenesis. It is also possible that cox-2 expression upregulates angiogenic factors in peri-neoplastic cells that express the isozyme. Interestingly, cox-1, the other isozyme that is expressed in tumor vascular endothelia, participates in tumor angiogenesis, because an anti-sense oligonucleotide of cox-1 suppresses in vitro angiogenesis induced by cox-2-overexpressing cells. A non-specific COX inhibitor, not a specific COX-2 inhibitor, reduced growth and angiogenesis in cancer xenografts by inhibition of COX-1 in vascular endothelial cells, even when the tumor did not express COX-2. These results demonstrate that COX inhibitors suppress angiogenesis and tumor growth by inhibiting expression of angiogenic factors and vascular endothelial cell migration. Furthermore, another concept is emerging to indicate that prostaglandins (COX-2 products and mediators of classic inflammation) suppress host immunity against tumors. This evidence supports the hypothesis that COX is an important perigenetic factor in the development of cancer growth, and offers a new strategy against cancer using COX inhibitors (nonsteroidal anti-inflammatory drugs).
No preview · Article · Apr 2001 · Journal of experimental & clinical cancer research: CR
[Show abstract][Hide abstract] ABSTRACT: Although ischemic stress, including ischemic preconditioning (IP), activates p38 mitogen-activated protein kinase (MAPK), the relationship between p38 MAPK activation and the underlying cellular mechanisms of cardioprotection by IP is not verified in vivo. We examined the effects of the selective p38 MAPK inhibition on the cardioprotective effect of IP in the open-chest dogs. The coronary artery was occluded 4 times for 5 minutes, separated by 5 minutes of reperfusion (IP) followed by 90 minutes of occlusion and 6 hours of reperfusion. We infused SB203580 into the coronary artery during IP and 1 hour of reperfusion, during IP alone, and during sustained ischemia in the IP group. p38 MAPK activity markedly increased during IP but did not additionally increase at the onset of ischemia and was even attenuated at 15 minutes of sustained ischemia, and heat-shock protein (HSP) 27 was phosphorylated and translocated from cytosol to myofibril or nucleus without affecting total protein level at the onset of ischemia compared with the control group. SB203580 treatment (1 micromol/L) only during IP blunted the infarct size limitation by IP (37.3+/-6.3% versus 7.4+/-2.1% in the IP group, P:<0.01) and attenuated either phosphorylation or translocation of HSP27 during IP. Although the SB203580 treatment throughout the preischemic and postischemic periods had no significant effect on infarct size (33.3+/-9.4%) in this model, treatment with SB203580 only during ischemia partially mimicked the infarct size limitation by IP (26.8+/-3.5%). Thus, transient p38 MAPK activation during ischemic preconditioning mainly mediates the cardioprotection followed by HSP27 phosphorylation and translocation in vivo in the canine heart.
Full-text · Article · Feb 2001 · Circulation Research
[Show abstract][Hide abstract] ABSTRACT: Connexin-43 is known to interact directly with ZO-1 in cardiac myocytes, but little is known about the role of ZO-1 in connexin-43 function. In cardiac myocytes, constitutively active c-Src inhibited endogenous interaction between connexin-43 and ZO-1 by binding to connexin-43. In HEK293 cells, by contrast, a connexin-43 mutant lacking the Src phosphorylation site (Tyr265) interacted with ZO-1 despite cotransfection of a constitutively active c-Src. Moreover, in vitro binding assays using recombinant proteins synthesized from regions of connexin-43 and ZO-1 showed that the tyrosine-phosphorylated C terminus of connexin-43 interacts with the c-Src SH2 domain in parallel with the loss of its interaction with ZO-1. Cell surface biotinylation revealed that, by phosphorylating Tyr265, constitutively active c-Src reduces total and cell surface connexin-43 down to the levels seen in cells expressing a mutant connexin-43 lacking the ZO-1 binding domain. Finally, electrophysiological analysis showed that both the tyrosine phosphorylation site and the ZO-1-binding domain of connexin-43 were involved in the regulation of gap junctional function. We therefore conclude that c-Src regulates the interaction between connexin-43 and ZO-1 through tyrosine phosphorylation and through the binding of its SH2 domain to connexin-43.
No preview · Article · Feb 2001 · Journal of Biological Chemistry