A Bayesian estimation method for cerebral blood flow measurement by area-detector CT perfusion imaging.

PURPOSE: Bayesian estimation with advanced noise reduction (BEANR) in CT perfusion (CTP) could deliver more reliable cerebral blood flow (CBF) measurements than the commonly used reformulated singular value decomposition (rSVD). We compared the efficacy of CBF measurement by CTP using BEANR and rSVD, evaluating both relative to N-isopropyl-p-[(123) I]- iodoamphetamine (123I-IMP) single-photon emission computed tomography (SPECT) as a reference standard, in patients with cerebrovascular disease. METHODS: Thirty-one patients with suspected cerebrovascular disease underwent both CTP on a 320 detector-row CT system and SPECT. We applied rSVD and BEANR in the ischemic and contralateral regions to create CBF maps and calculate CBF ratios from the ischemic side to the healthy contralateral side (CBF index). The analysis involved comparing the CBF index between CTP methods and SPECT using Pearson's correlation and limits of agreement determined with Bland-Altman analyses, before comparing the mean difference in the CBF index between each CTP method and SPECT using the Wilcoxon matched pairs signed-rank test. RESULTS: The CBF indices of BEANR and 123I-IMP SPECT were significantly and positively correlated (r = 0.55, p < 0.0001), but there was no significant correlation between the rSVD method and SPECT (r = 0.15, p > 0.05). BEANR produced smaller limits of agreement for CBF than rSVD. The mean difference in the CBF index between BEANR and SPECT differed significantly from that between rSVD and SPECT (p < 0.001). CONCLUSIONS: BEANR has a better potential utility for CBF measurement in CTP than rSVD compared to SPECT in patients with cerebrovascular disease.

Improving compliance with guidelines may lead to favorable clinical outcomes for patients with non-muscle-invasive bladder cancer: A retrospective multicenter study.

OBJECTIVES: Clinical guidelines recommend that patients with non-muscle-invasive bladder cancer (NMIBC) should be treated with appropriate adjuvant therapy. However, compliance with guideline recommendations is insufficient, and this may lead to unfavorable outcomes. We aimed to investigate the level of adherence to guideline recommendations in patients with NMIBC and evaluate the outcomes of those who did and did not receive guideline-recommended therapies. METHODS: We performed a retrospective analysis of patients with histologically diagnosed NMIBC. The percentage of patients with intermediate- and high-risk tumors who received adjuvant intravesical therapy or second transurethral resection (TUR) was calculated. Recurrence-free survival was assessed in patients who did and did not receive the therapies. We conducted a propensity score-matched analysis to compare outcomes between patients with intermediate-risk and T1 NMIBC who did and did not undergo guideline-recommended therapies. RESULTS: Overall, 1204 patients from the Tohoku Urological Evidence-Based Medicine Study Group and Kyoto University Hospital were included. Of patients with intermediate- and high-risk tumors, 91.0% and 74.0% did not receive maintenance bacillus Calmette-Guérin (BCG), respectively. In both groups, significantly better recurrence-free survival was found for patients treated with maintenance BCG. Among patients with T1 NMIBC, only 16.7% underwent guideline-recommended therapies, that is, a second TUR and maintenance BCG. Significantly greater recurrence-free survival was observed in patients who received guideline-recommended therapies compared with propensity-matched patients who did not. CONCLUSIONS: Guideline-recommended therapies may contribute to improvements in outcomes for patients with NMIBC, suggesting that improvements in adherence to clinical guidelines may lead to favorable outcomes.

Single-incision laparoscopic totally extraperitoneal inguinal hernia repair with tumescent local anesthesia: report of more than 2000 procedures at a day-surgery clinic.

PURPOSE: The purpose of this study was to evaluate the feasibility and safety of single-incision laparoscopic surgery for totally extraperitoneal inguinal hernia repair (SILS-TEP) with tumescent local anesthesia (TLA) at a day-surgery clinic. METHODS: We analyzed, retrospectively, 2148 patients who underwent SILS-TEP under general anesthesia with TLA between April, 2015 and March, 2020 at Gi surgical clinic, to evaluate their operative outcomes. The TLA agent, consisting of normal saline and lidocaine with epinephrine and ropivacaine, was injected during surgery. RESULTS: The median operative times for unilateral and bilateral hernia were 50 min and 75 min, respectively. Blood loss was minimal in all patients. Conversion to the Lichtenstein method was required in 4% (91/2148) of patients. The median recovery room stay was 125 min and no analgesics were required in the recovery room by 75% (1613/2148) of the patients. All the patients left the clinic on the day of surgery. Complications developed in 6.5% (139/2148) of the patients, as seromas in 6% (125/2148), wound infections in 0.4% (8/2148), and hematomas in 0.2% (4/2148), respectively. Bowel injury and obstruction each occurred in 0.05% (1/2148) of the patients. There were no hernia recurrences. CONCLUSION: SILS-TEP with TLA can be performed safely at a day-surgery clinic.

Efficacy of early ureteral ligation on prevention of intravesical recurrence after radical nephroureterectomy for upper urinary tract urothelial carcinoma: a prospective single-arm multicenter clinical trial.

OBJECTIVE: The rate of intravesical recurrence after radical nephroureterectomy for upper urinary tract urothelial carcinoma is high. Seeding upper urinary tract urothelial carcinoma cells onto the damaged bladder wall is considered to be one of the causes of intravesical recurrence after radical nephroureterectomy. We evaluated the utility of early ureteral ligation in preventing the intravesical recurrence. METHODS: This prospective single-arm clinical trial included patients who underwent radical nephroureterectomy for upper urinary tract urothelial carcinoma in the Tohoku Urological Evidence-Based Medicine Study Group between 2012 and 2013. Early ureteral ligation was defined as ligation of the ureter as quickly as possible after expanding the retroperitoneal space. A historical control was extracted from 454 patients who underwent radical nephroureterectomy in the same group, using propensity score-matched analysis. Intravesical recurrence-free survival rates were analyzed using Kaplan-Meier curves. Factors predicting intravesical recurrence were assessed using multivariate analyses. RESULTS: Seventy-four patients underwent early ureteral ligation. Seventeen (23%) patients had intravesical recurrence with a median follow-up period of 24 months. The 1- and 2-year intravesical recurrence-free survival rates in the early ureteral ligation group were 81% and 76%, and in the control group 75% and 63%, respectively (P = 0.160). In patients with renal pelvic cancer, the 1- and 2-year intravesical recurrence-free survival rates in the early ureteral ligation group were 89% and 86%, but in the control group 74% and 64%, respectively (P = 0.025). However, intravesical recurrence-free survival rates were similar in patients with ureteral cancer. Multivariate analyses of a subset of patients with renal pelvic cancer identified early ureteral ligation as an independent predictor of intravesical recurrence. CONCLUSIONS: Early ureteral ligation decreases the rate of intravesical recurrence after radical nephroureterectomy in patients with renal pelvic cancer. Thus, early ureteral ligation might help in prevention of intravesical recurrence for renal pelvic cancer.

Renal epithelioid angiomyolipoma with malignant features: Histological evaluation and novel immunohistochemical findings.

Renal epithelioid angiomyolipoma (EAML) is a potentially malignant tumor type whose characteristics and biomarkers predictive of malignant behavior have not been elucidated. Here, we report three cases of renal EAML with malignant features but without histories of tuberous sclerosis complex. Case 1 involved a 29-year-old man with a 12-cm solid mass in the right kidney who underwent radical right nephrectomy. Case 2 involved a 22-year-old woman with a retroperitoneal mass who underwent radical right nephrectomy and retroperitoneal tumorectomy. Local recurrence was detected 7 years post-surgery. Case 3 involved a 23-year-old man with a 14-cm solid mass in the left kidney who underwent radical left nephrectomy. Microscopically, the tumors in all cases demonstrated proliferation of epithelioid cells with atypia, mitotic activity, necrosis, hemorrhage, and vascular invasion. Epithelioid cells in all cases were immunohistochemically positive for melanocytic and myoid markers and weakly positive for E-cadherin and ß-catenin. Immunohistochemistry revealed activation of the mammalian target of rapamycin pathway. Here, we report the morphological and immunohistochemical features of clinically or histologically malignant renal EAML.

Copper deficiency anemia due to zinc supplementation in a chronic hemodialysis patient.

Zinc deficiency causes dysgeusia and dermatitis as well as anemia. As approximately half of dialysis patients have zinc deficiency, zinc supplementation should be considered in case of erythropoiesis-stimulating agent (ESA)-hyporesponsive anemia. We report a case of a chronic dialysis patient with copper deficiency anemia caused by standard-dose zinc supplementation. The patient was a 70-year-old woman who had received maintenance hemodialysis for 8 years due to diabetic nephropathy. She had been treated with weekly administration of darbepoetin 30 µg for renal anemia, which resulted in Hb 12 to 14 g/dL. She had no dysgeusia. When zinc deficiency (44 µg/dL) had been identified 4 months earlier, 50 mg daily zinc acetate hydrate (Nobelzin®), which is the standard dose, was started. Unexpectedly, her anemia progressed slowly with macrocytosis together with granulocytopenia. Her platelet count did not decrease at that time. Laboratory tests revealed a marked decrease of serum copper (< 4 µg/dL) and ceruloplasmin (< 2 mg/dL), although serum zinc was within the normal limit (125 µg/dL). We discontinued zinc acetate and started copper supplementation including cocoa for 1 month. Her anemia and granulocytopenia were dramatically restored coincident with the increase in both serum copper and ceruloplasmin. Copper supplementation also improved her iron status as assessed by transferrin saturation and ferritin. Clinicians should monitor both zinc and copper status in anemic dialysis patients during zinc supplementation, as both are important to drive normal hematopoiesis.

Machine learning-based computer-aided simple triage (CAST) for COVID-19 pneumonia as compared with triage by board-certified chest radiologists.

PURPOSE: Several reporting systems have been proposed for providing standardized language and diagnostic categories aiming for expressing the likelihood that lung abnormalities on CT images represent COVID-19. We developed a machine learning (ML)-based CT texture analysis software for simple triage based on the RSNA Expert Consensus Statement system. The purpose of this study was to conduct a multi-center and multi-reader study to determine the capability of ML-based computer-aided simple triage (CAST) software based on RSNA expert consensus statements for diagnosis of COVID-19 pneumonia. METHODS: For this multi-center study, 174 cases who had undergone CT and polymerase chain reaction (PCR) tests for COVID-19 were retrospectively included. Their CT data were then assessed by CAST and consensus from three board-certified chest radiologists, after which all cases were classified as either positive or negative. Diagnostic performance was then compared by McNemar's test. To determine radiological finding evaluation capability of CAST, three other board-certified chest radiologists assessed CAST results for radiological findings into five criteria. Finally, accuracies of all radiological evaluations were compared by McNemar's test. RESULTS: A comparison of diagnosis for COVID-19 pneumonia based on RT-PCR results for cases with COVID-19 pneumonia findings on CT showed no significant difference of diagnostic performance between ML-based CAST software and consensus evaluation (p > 0.05). Comparison of agreement on accuracy for all radiological finding evaluations showed that emphysema evaluation accuracy for investigator A (AC = 91.7%) was significantly lower than that for investigators B (100%, p = 0.0009) and C (100%, p = 0.0009). CONCLUSION: This multi-center study shows COVID-19 pneumonia triage by CAST can be considered at least as valid as that by chest expert radiologists and may be capable for playing as useful a complementary role for management of suspected COVID-19 pneumonia patients as well as the RT-PCR test in routine clinical practice.

A novel antiangiogenic effect for telomerase-specific virotherapy through host immune system.

Soluble factors in the tumor microenvironment may influence the process of angiogenesis; a process essential for the growth and progression of malignant tumors. In this study, we describe a novel antiangiogenic effect of conditional replication-selective adenovirus through the stimulation of host immune reaction. An attenuated adenovirus (OBP-301, Telomelysin), in which the human telomerase reverse transcriptase promoter element drives expression of E1 genes, could replicate in and cause selective lysis of cancer cells. Mixed lymphocyte-tumor cell culture demonstrated that OBP-301-infected cancer cells stimulated PBMC to produce IFN-gamma into the supernatants. When the supernatants were subjected to the assay of in vitro angiogenesis, the tube formation of HUVECs was inhibited more efficiently than recombinant IFN-gamma. Moreover, in vivo angiogenic assay using a membrane-diffusion chamber system s.c. transplanted in nu/nu mice showed that tumor cell-induced neovascularization was markedly reduced when the chambers contained the mixed lymphocyte-tumor cell culture supernatants. The growth of s.c. murine colon tumors in syngenic mice was significantly inhibited due to the reduced vascularity by intratumoral injection of OBP-301. The antitumor as well as antiangiogenic effects, however, were less apparent in SCID mice due to the lack of host immune responses. Our data suggest that OBP-301 seems to have antiangiogenic properties through the stimulation of host immune cells to produce endogenous antiangiogenic factors such as IFN-gamma.

Risk factors for overactive bladder in the elderly population: a community-based study with face-to-face interview.

OBJECTIVES: The aim of this study was to measure the prevalence of and risk factors for overactive bladder (OAB) in the elderly. METHODS: A cross-sectional study of elderly subjects was conducted by analyzing data from a community-based Comprehensive Geriatric Assessment on people aged 70 years or older. Trained interviewers performed face-to-face interviews for the assessment of urological symptoms. OAB definition was based on urgency and eight or more episodes of urination per day. The subjects completed a self-administered questionnaire including lifestyle evaluation, Geriatric Depression Scale, Mini-Mental Status Examination and medical history. Brachial-ankle pulse wave velocity was recorded to assess atherosclerotic disease. The analysis included 833 subjects, after the exclusion of 115 subjects who provided insufficient information. RESULTS: Based on the definition of OAB, 153 subjects (18.4%) were identified as having OAB. Univariate analysis showed a significant association between OAB and depressive symptoms. Multivariate analysis showed that the risk of having OAB was significantly higher in subjects with depressive symptoms, current drinkers, and overweight subjects with odds ratios of 2.37 (1.60-3.52, 95% confidence interval), 1.65 (1.04-2.62), and 1.51 (1.02-2.24), respectively. CONCLUSIONS: This is the first report to show an association between OAB and depressive symptoms and alcohol intake in an epidemiological study of elderly people. The reasons for these correlations remain unclear, but should be the foci of future OAB studies.

Structural basis for regulation of poly-SUMO chain by a SUMO-like domain of Nip45.

Post-translational modification by small ubiquitin-like modifier (SUMO) provides an important regulatory mechanism in diverse cellular processes. Modification of SUMO has been shown to target proteins involved in systems ranging from DNA repair pathways to the ubiquitin-proteasome degradation system by the action of SUMO-targeted ubiquitin ligases (STUbLs). STUbLs recognize target proteins modified with a poly-SUMO chain through their SUMO-interacting motifs (SIMs). STUbLs are also associated with RENi family proteins, which commonly have two SUMO-like domains (SLD1 and SLD2) at their C terminus. We have determined the crystal structures of SLD2 of mouse RENi protein, Nip45, in a free form and in complex with a mouse E2 sumoylation enzyme, Ubc9. While Nip45 SLD2 shares a beta-grasp fold with SUMO, the SIM interaction surface conserved in SUMO paralogues does not exist in SLD2. Biochemical data indicates that neither tandem SLDs or SLD2 of Nip45 bind to either tandem SIMs from either mouse STUbL, RNF4 or to those from SUMO-binding proteins, whose interactions with SUMO have been well characterized. On the other hand, Nip45 SLD2 binds to Ubc9 in an almost identical manner to that of SUMO and thereby inhibits elongation of poly-SUMO chains. This finding highlights a possible role of the RENi proteins in the modulation of Ubc9-mediated poly-SUMO formation.

Impact of nocturia on bone fracture and mortality in older individuals: a Japanese longitudinal cohort study.

PURPOSE: We evaluated the association of nocturia with fracture and death in a large, community based sample of Japanese individuals 70 years old or older. MATERIALS AND METHODS: The baseline in this population based study was determined in 2003 by an extensive health interview with each participant. In this study we followed 784 individuals with a mean ± SD age of 76.0 ± 4.6 years (range 70 to 97). Information on mortality and fracture during the study period was provided by the National Health Insurance system and details on fractures were collected from medical records. We compared the risk of bone fracture and death with or without nocturia in a multivariate Cox proportional hazard model. RESULTS: Nocturia (2 or greater voids per night) was present in 359 of the 784 participants (45.7%). Fracture was observed in 41 cases, including 32 fall related cases. For all fractures and fall related fractures with nocturia the HR was 2.01 (95% CI 1.04-3.87) and 2.20 (95% CI 1.04-4.68, each p = 0.04). Death occurred in 53 cases. The mortality rate in individuals with nocturia was significantly higher than in those without nocturia. For mortality in patients with nocturia the age-gender adjusted HR was 1.91 (95% CI 1.07-3.43, p = 0.03). Even when further adjusted for diabetes, smoking status, history of coronary disease, renal disease and stroke, tranquilizers, hypnotics and diuretics, the positive relationship was unchanged (HR 1.98, 95% CI 1.09-3.59, p = 0.03). CONCLUSIONS: During a 5-year observation period elderly individuals with nocturia were at greater risk for fracture and death than those without nocturia.

[Effects of urinary function and erectile function on the use of mecobalamin after nerve sparing radical prostatectomy].

PURPOSE: Mecobalamin has been reported to be useful for peripheral nerve disorder. There have been no previous reports of the effects of mecobalamin on urinary and sexual function after nerve sparing radical prostatectomy. We examined the effects of the use of mecobalamin on urinary and erectile functions after nerve sparing radical prostatectomy. MATERIALS AND METHODS: A total of 54 patients with localized prostatic cancer were prospectively randomized into 2 groups. The 27 patients in group A were treated with nerve sparing prostatectomy and mecobalamin 1,500 microg/day for 6 months. The 27 patients in group B were treated with nerve sparing prostatectomy alone. Urinary function (URF), urinary bother (URB), sexual function (SXF) and sexual bother (SXB) were evaluated using the University of California at Los Angeles Prostate Cancer Index (UCLA-PCI) before surgery, and 3, 6 and 12 months after surgery. RESULTS: There were no significant differences in URF, URB, SXF or SXB between the two groups at any postoperative period. At 3 months after surgery, however, group A tended to have a better URF than group B (85.7 +/- 4.7 (mean +/- standard error) vs. 66.9 +/- 10.2) and URB (85.7 +/- 7.4 vs. 63.9 +/- 11.8) (p = 0.121, p = 0.168). At 12 months after surgery, both groups showed similar URF (86.4 +/- 7.4 vs. 81.8 +/- 4.2) and URB (86.5 +/- 8.3 vs. 84.5 +/- 4.7). Although the two groups had similar recovery phase of SXF, group A tended to report better SXB throughout the postoperative period. CONCLUSION: This study did not demonstrate any significant effect of the use of mecobalamin on the recovery of urinary or sexual function after nerve sparing prostatectomy, although an early recovery effect on urinary function was suggested. A randomized controlled study with a larger population is warranted to fully elucidate the role of mecobalamin in the improvement of functional outcome after radical prostatectomy.

Potentiation of potassium currents by beta-adrenoceptor agonists in human urinary bladder smooth muscle cells: a possible electrical mechanism of relaxation.

We examined the effects of beta-adrenoceptor agonists on the membrane currents of smooth muscle cells from the human urinary bladder using a whole-cell patch clamp to investigate the involvement of Ca(2+)-activated K(+) (K(Ca)) channels in relaxation by beta-adrenergic agonists. With 0.05 mmol/l EGTA in the patch pipette, depolarizing pulses evoked outward rectifying currents. Isoproterenol (1 micromol/l) significantly increased the membrane currents by 75% at +80 mV with 0.05 mmol/l EGTA pipette solution. BRL 37344 (1 micromol/l) significantly increased the membrane currents by 44% at +80 mV. Iberiotoxin (100 nmol/l) significantly decreased the membrane currents by 60% at +80 mV. In the presence of iberiotoxin, the potentiation of the outward currents by isoproterenol was greatly suppressed and, in the presence of iberiotoxin and apamin (1 micromol/l), the potentiation by isoproterenol was totally abolished. On the other hand, with 5 mmol/l EGTA pipette solution, depolarizing pulses evoked smaller outward currents. Isoproterenol (1 micromol/l) did not change the membrane currents with 5 mmol/l EGTA pipette solution. The real-time PCR analysis revealed the expression of beta(2)-adrenoceptors in the cells. These results suggest that Ca(2+)-activated and iberiotoxin- and apamin-sensitive currents via both large-conductance and small-conductance K(Ca) channels could be increased by stimulation of beta(2)-adrenoceptors.

Spontaneous regression of pulmonary metastases from testicular embryonal carcinoma.

A 22-year-old man was referred to our hospital for a lung tumor on a chest X-ray examination. Computed tomography of the chest revealed multiple coin lesions. Magnetic resonance imaging of the left testis showed an 8-mm tumor that was hard and palpable. Testicular tumor with lung metastasis was diagnosed and orchiectomy was performed. The histopathological diagnosis was embryonal carcinoma with infiltration of histiocytes. Four days after the operation, a chest X-ray showed a remarkable regression of the lung tumors. Chemotherapy was not performed because the metastatic lesions continued to regress spontaneously. Six months later, no tumor was observed on computed tomography images of the lungs.

[Pulmonary and lymph node metastases of renal cell carcinoma which completely responded to oral administration of UFT--a case report].

In April 2003, a 59-year-old woman suffering from renal cell carcinoma (RCC) underwent radical nephrectomy (Stage I). In October 2004, bilateral lower lobe lung tumors were resected with thoracoscopic assistance. Histologically, resected specimens were diagnosed as metastases from RCC. However, 2 months later,lung and abdominal lymph node metastases were detected by CT. Chemotherapy with interferon-alpha (IFN-alpha) 6,000,000 units every day was performed, but was discontinued after 3 months due to fatigue and depression. Because the tumor marker (IAP) level and the size of the metastatic tumors increased, second-line chemotherapy with oral administration of tegafur/uracil (UFT-E 600 mg/day) was started. Six months after UFT administration, there was a significant decrease of tumor markers and the metastatic tumors were disappeared, therefore we were judged as complete response (CR). No grade 3 or more severs adverse reactions have been observed. Some cases may be effectively treated by UFT after treatment failure of IFN-alpha therapy. This UFT therapy is simple and possible to continue safely on an outpatient chemotherapy while maintaining quality of life.

MitoKATP channel activation suppresses gap junction permeability in the ischemic myocardium by an ERK-dependent mechanism.

BACKGROUND: Ischemic preconditioning accelerates suppression of gap junction (GJ) permeability during myocardial ischemia, and GJ blockers reduce infarct size. We hypothesized that the mitochondrial ATP-sensitive K+ (mitoKATP) channel is one of the mechanisms regulating GJ permeability through the mitogen-activated protein kinase ERK, leading to cardioprotection. METHODS AND RESULTS: In isolated rabbit hearts, tissues were sampled before and after infusion of diazoxide, a selective mitoKATP channel opener, and their intercalated disc-rich fractions were obtained for immunoblotting of mitogen-activated protein kinases. GJ permeability in the myocardium was assessed by using Lucifer yellow as a tracer of GJ communication. Infarction was induced by 30-min global ischemia/2 h reperfusion, and infarct size was expressed as a percent of area-at-risk (%IS/AR). Diazoxide (100 microM) induced phosphorylation of ERK1/2 and 279Ser/282Ser of connexin-43, a GJ subunit protein, and phospho-ERK1/2 was co-immunoprecipitated with connexin-43 in the diazoxide-treated myocardium. This ERK1/2 phosphorylation by diazoxide was inhibited by N-2-mercaptopropionyl-glycine, a free radical scavenger. Diazoxide at 10 and 100 microM reduced intercellular transport of Lucifer yellow during ischemia by 44% and 69%, respectively, and this effect of diazoxide on GJ communication was abolished by PD98059, an ERK inhibitor. Pretreatment with 10 microM and 100 microM diazoxide reduced %IS/AR from 57.1+/-3.7% to 21.5+/-10.5% and 5.0+/-1.3%, respectively. PD98059 abolished cardioprotection by 10 microM diazoxide but not that by 100 microM diazoxide. CONCLUSIONS: Opening of the mitoKATP channel activates ERK1/2 via free radicals and induces ERK-mediated suppression of GJ permeability. This suppression of GJ permeability may partly contribute to cardioprotection afforded by mitoKATP channel activation.

Intracardiac fibroblasts, but not bone marrow derived cells, are the origin of myofibroblasts in myocardial infarct repair.

UNLABELLED: Origin of myofibroblasts in infarcted myocardium was examined by using rats in which bone marrow of green fluorescent protein (GFP)-transgenic mice had been transplanted. GFP was not detected in myofibroblasts at either 3 or 7 days after infarction, suggesting that proliferating myofibroblasts in infarcted myocardium are derived from resident fibroblasts rather than circulating precursor cells of bone marrow origin. BACKGROUND: Myofibroblasts play important roles in the repair process of myocardial infarct, and their origin has been assumed to be interstitial fibroblasts in the heart. However, bone marrow-derived myofibroblasts have recently been identified in pathological fibrosis in extracardiac tissues. In this study, we aimed to determine whether some of the myofibroblasts in infarcted myocardium are derived from circulating precursor cells of bone marrow origin. METHODS AND RESULTS: Bone marrow (BM) of GFP-transgenic mice was transplanted into nude rats, and their coronary arteries were occluded for 60 min and reperfused for 3 or 7 days. Non-BM-transplanted rats served as controls. At 3 days after infarction, some endothelial cells were GFP-positive, indicating that they were of bone marrow origin. Predominant cells in infarcted regions were macrophages and neutrophils, and there were only a small number of vimentin-positive cells and fewer myofibroblasts, both of which were GFP-negative. At 7 days after infarction, there were numerous myofibroblasts in granulation tissue replacing necrotic myocytes, and none of them showed GFP signals, whereas some cells were positive for both GFP and vimentin. Appearance of myofibroblasts and extent of the infarct repair in BM-transplanted and those in non-transplanted rats were similar. CONCLUSIONS: The findings in this study suggest that proliferating myofibroblasts in infarcted myocardium are derived from resident fibroblasts rather than circulating precursor cells of bone marrow origin.

Ischemic preconditioning activates AMPK in a PKC-dependent manner and induces GLUT4 up-regulation in the late phase of cardioprotection.

OBJECTIVE: The aim of this study was to determine the role of AMP-activated protein kinase (AMPK) and its link to protein kinase C (PKC) in the late phase of cardioprotection afforded by ischemic preconditioning (PC) against myocardial stunning. METHODS AND RESULTS: Rabbits were instrumented with a balloon occluder around a coronary artery and with a Doppler sensor to monitor the thickening fraction (TF). Conscious rabbits underwent five cycles of 5-min ischemia/5-min reperfusion (I/R) on 2 consecutive days (days 1 and 2). Reduction of TF after I/R was significantly less and recovery of TF was faster on day 2, indicating a late PC effect. PC provoked translocation of PKC- from the cytosol to the membrane and significantly increased AMPK activity by 100% immediately after PC. The mRNA level of GLUT4, a glucose transporter, was elevated by 150% at 3 h after PC, and the total protein level of GLUT4 was increased by 107% at 24 h after PC. The level of sarcolemmal GLUT4 protein after I/R on day 2 was 41% higher than its level after I/R on day 1. AMPK activation and up-regulation of GLUT4 by PC were abrogated by pre-treatment with PKC inhibitors. CONCLUSION: PC activated AMPK and up-regulated GLUT4 expression in a PKC-dependent manner. This GLUT4 up-regulation at 24 h after PC may contribute to attenuation of myocardial stunning.

Role of microtubules in ischemic preconditioning against myocardial infarction.

OBJECTIVE: The role of microtubules in ischemic preconditioning (PC) was investigated in isolated perfused rabbit hearts. METHODS: Myocardial infarction was induced by 30-min global ischemia and 2-h reperfusion, and infarct size was expressed as a percentage of the left ventricle (%IS/LV). Using separate groups of rabbits, ventricular biopsies were taken before and after PC for determination of protein kinase C (PKC) translocation and p38-mitogen-activated protein kinase (p38MAP kinase) activation. To depolymerize microtubules, we used two structurally different agents, colchicine (50 microM) and nocodazole (1 microM). RESULTS: PC with two cycles of 5-min ischemia/5-min reperfusion significantly reduced infarct size from 60.1+/-5.0% to 20.0+/-5.0%. Although neither colchicine nor nocodazole modified infarct size in nonpreconditioned hearts, these agents abolished the infarct size-limiting effects of PC (%IS/LV=56.1+/-6.0% and 53.5+/-2.5%, respectively). Colchicine prevented translocation of PKC-epsilon and p38MAP kinase activation by PC. PKC translocation by infusion of 1-oleyl-2-acetyl-sn-glycerol in nonischemic hearts was also prevented by colchicine. CONCLUSION: Microtubules play a crucial role in the development of anti-infarct tolerance by PC as a mechanism supporting translocation of activated PKC.

Decreased expression of arginase II in the kidneys of Dahl salt-sensitive rats.

Arginase catalyzes the hydrolysis of arginine to urea and ornithine. Urea is not only an important solute for concentrating urine but also inhibits Na-K-2Cl cotransport. To elucidate the roles of arginase in the development of salt-sensitive hypertension, we examined arginase activity and expression in the kidney and other organs of Dahl/Rapp salt-sensitive (SS) and salt-resistant (SR) rats before and after 4 weeks' administration of a 4% NaCl or control diet. At 4 weeks of age, arginase activity in the kidney was lower in SS rats than in SR rats. Kidney arginase activity was lower in SS rats than in SR rats at 8 weeks of age, and salt loading did not alter arginase activity. Arginase II (the dominant isoform in the kidney) mRNA and protein in the kidney of salt-loaded SS rats were also lower than those of salt-loaded SR rats. Arginase activities in the liver and cerebellum did not differ between SS and SR rats. To examine the effect of urea, the product of arginase reaction, on the development of hypertension, SS rats were given a 4% NaCl diet containing 5% kaolin or 5% urea. Six-week urea supplementation attenuated the development of hypertension in SS rats. These findings suggest that decreased arginase expression in the kidney may be at least partially responsible for the salt-sensitive hypertension in SS rats.