Unique SMAD1/5/8 activity at the phalanx-forming region determines digit identity

The zone of polarizing activity is the primary signaling center controlling anterior-posterior patterning of the amniote limb bud. The autopodial interdigits (IDs) are secondary signaling centers proposed to determine digit identity by acting on the cells of the digital ray. Here, we focus on events accompanying digital fate determination and define a region of the digital ray that expresses Sox9 and Bmpr1b and is phosphorylated-SMAD1/5/8 (p-SMAD1/5/8) positive. We name this region the phalanx-forming region (PFR), and show that the PFR cells arise from the distal subridge mesenchyme of digital ray. This phalanx-forming cell lineage is subsequently committed to the cartilage lineage; the fate of these cells is initially labile but becomes fixed as they are incorporated into the condensed cartilage of the digit primordium. Using an in vivo reporter assay, we establish that each digital PFR has a unique p-SMAD1/5/8 activity signature. In addition, we show that changes in this activity correlate with the identity of the digit that forms after experimental manipulation, supporting the idea that threshold signaling levels can lead to different developmental outcomes in a morphogenetic field. Our data define the molecular profile of the PFR, and we propose a model for understanding formation and variation of digits during autopodial development.     

Pitavastatin, an HMG-CoA reductase inhibitor, exerts eNOS-independent protective actions against angiotensin II induced cardiovascular remodeling and renal insufficiency

Angiotensin II (Ang II) plays a pivotal role in cardiovascular remodeling leading to hypertension, myocardial infarction, and stroke. Pitavastatin, an HMG-CoA reductase inihibitor, is known to have pleiotropic actions against the development of cardiovascular remodeling. The objectives of this study were to clarify the beneficial effects as well as the mechanism of action of pitavastatin against Ang II-induced organ damage. C57BL6/J mice at 10 weeks of age were infused with Ang II for 2 weeks and were simultaneously administered pitavastatin or a vehicle. Pitavastatin treatment improved Ang II-induced left ventricular hypertrophy and diastolic dysfunction and attenuated enhancement of cardiac fibrosis, cardiomyocyte hypertrophy, coronary perivascular fibrosis, and medial thickening. Ang II-induced oxidative stress, cardiac TGFbeta-1 expression, and Smad 2/3 phosphorylation were all attenuated by pitavastatin treatment. Pitavastatin also reduced Ang II-induced cardiac remodeling and diastolic dysfunction in eNOS-/- mice as in wild-type mice. In eNOS-/- mice, the Ang II-induced cardiac oxidative stress and TGF-beta-Smad 2/3 signaling pathway were enhanced, and pitavastatin treatment attenuated the enhanced oxidative stress and the signaling pathway. Moreover, pitavastatin treatment reduced the high mortality rate and improved renal insufficiency in Ang II-treated eNOS-/- mice, with suppression of glomerular oxidative stress and TGF-beta-Smad 2/3 signaling pathway. In conclusion, pitavastatin exerts eNOS-independent protective actions against Ang II-induced cardiovascular remodeling and renal insufficiency through inhibition of the TGF-beta-Smad 2/3 signaling pathway by suppression of oxidative stress.     

A case of intravascular large cell lymphoma with pulmonary invasion]

A 60-year-old man was admitted to our hospital because of dyspnea, cough, and fever two weeks after participating demolition work. Computed tomography of the chest showed multiple diffuse interstitial shadows. While fibrotic bronchoscopy and transbronchial lung biopsy showed alveolitis. We diagnosed hypersensitivity pneumonitis (HP) and treated with mPSL-pulse therapy then got better soon, and also chest abnormal shadow disappeared. Two month later he was admitted because of the same symptom. His chest CT-scans showed diffuse interstitial shadows and we diagnosed recurrence of HP. Treatment with mPSL pulse-therapy was not effective. Acute respiratory failure appeared and progressed daily. The patient died 3 weeks after admission. The final diagnosis of autopsy is angiotrophic large cell lymphoma, a very rare type of lymphoma (<1% of NHL). It is important to consider angiotrophic large cell lymphoma in the differential diagnosis of diffuse interstitial lung disease.     

Enterovesical fistulas complicating Crohn's disease: clinicopathological features and management

Enterovesical fistula is a relatively rare condition in Crohn's disease. This study was undertaken to examine clinicopathological features and management of enterovesical fistula complicating Crohn's disease. Thirty patients with enterovesical fistula complicating Crohn's disease, treated between 1970 and 1997, were reviewed. Urological symptoms were present in 22 patients; pneumaturia in 18, urinary tract infection in 7, and haematuria in 2. In 5 patients clinical symptoms were successfully managed by conservative treatment, and they required no surgical treatment for enterovesical fistula. Twenty-five patients required surgery. All the patients were treated by resection of diseased bowel and pinching off the dome of the bladder. No patients required resection of the bladder. The Foley catheter was left in situ for an average of 2 weeks after operation. Three patients developed early postoperative complications; two bowel anastomotic leaks, and one intra-abdominal abscess. All these complications were associated with sepsis and multiple fistulas at the time of laparotomy. After a median follow-up of 13 years, 3 patients having postoperative sepsis (anastomotic leak or abscess) developed a recurrent fistula from the ileocolonic anastomosis to the bladder, which required further surgery. In the other 22 patients without postoperative complications there has been no fistula recurrence. In conclusion, the majority of patients with enterovesical fistula required surgical treatment: resection of the diseased bowel and oversewing the defect in the bladder. The fistula recurrence was uncommon, but the presence of sepsis and multiple fistulas at the time of laparotomy increased the incidence of postoperative complications and fistula recurrence.     

Infarct Size Limitation by Bradykinin Receptor Activation Is Mediated by the Mitochondrial But Not by the Sarcolemmal KATP Channel

Earlier studies have shown that activation of bradykinin B₂ receptor triggers protein kinase C (PKC)-mediated cardioprotective mechanism in ischemic preconditioning (PC). In the present study, we examined whether the effector in this B₂-receptor triggered pathway of PC is the ATP sensitive potassium (K_ATP) channel in the mitochondria (mito-K_ATP channel) or K_ATP channel in the sarcolemma (sarc-K_ATP channel). Isolated rabbit hearts were perfused with modified Krebs-Henseleit buffer in a Langendorff mode, and regional myocardial ischemia was induced by occluding a left coronary artery for 30 min and then reperfusing for 2 hours. Infarct size was determined by triphenyltetrazolium chloride staining and expressed as a percentage of area at risk (% IS/AR). Infusion of bradykinin (500 nmol/L) for 15 min prior to ischemia significantly reduced % IS/AR from 37.4 ± 2.9 (SE) of the untreated controls to 12.0 ± 3.3%. This protective effect of bradykinin was completely abolished by coinfusion of 5-hydroxydecanoate (5-HD, 50 mol/L), a selective mito-K_ATP channel blocker (% IS/AR = 44.2 ± 6.4). In contrast, a high dose of HMR1098 (20 mol/L), which is a newly developed sarc-K_ATP channel selective blocker with IC₅₀ of 0.6 mol/L, failed to modify the infarct size limitation by preischemic infusion of bradykinin (% IS/AR = 11.7 ± 3.4). Neither 5-HD nor HMR1098 alone modified infarct size (% IS/AR = 37.8 ± 3.8 and 35.1 ± 6.2, respectively). These results suggest that opening of the mito-K_ATP channel but not the sarc-K_ATP channel is involved in infarct size limitation by a mechanism triggered by bradykinin B₂ receptor activation.     

Insulin alters cardiac muscle creatine kinase activity

The expression of mRNAs of creatine kinase (CK)-B and CK-M has been show to be affected by insulin, and myocardial CK-MB activity is suppressed in insulin-deficient rats. We investigated the dose-related effect of insulin on CK-MB activity in cardiac and skeletal muscles. Male Wistar rats were divided into three groups: (1) control group, (2) diabetic group, injected with 65 mg/kg streptozotocin for 4 weeks, and (3) atenolol group, administered 30 mg/kg per day atenolol. Each group was further divided into three subgroups and administered either saline, or 20 (Ins 20) or 30 (Ins 30) U/kg per day insulin. After 3 weeks, the isoenzyme activity of CK and lactate dehydrogenase (LDH) in the left ventricle of the heart (LV) and the major pectoral muscle (PM) was measured. Serum insulin increased and plasma glucose decreased in Ins 20 and Ins 30, dose-dependently, in all three groups. Both CK-MB and -BB activity in LV increased dose-dependently with insulin treatment in the control, diabetes, and atenolol groups, although these changes did not occur in skeletal muscles. CK-MB in LV correlated with the serum insulin levels in all rats, while no correlation was found in the skeletal muscles. These findings suggest that insulin possibly regulates the distribution of CK isoenzymes in rat heart muscle, and that the effect of insulin is not due to the sympathetic drive induced by hypoglycemia. Received: November 8, 1999 / Accepted: February 12, 2000     

Immunoblastic lymphadenopathy-like T-cell lymphoma complicated by multiple gastrointestinal involvement

We report a rare case of immunoblastic lymphadenopathy (IBL)-like T-cell lymphoma complicated by multiple gastrointestinal involvement, which appeared to be ameliorated by chemotherapy but resulted in perforative peritonitis. A 66-year-old Japanese woman who had generalized lymphadenopathy and eruptions was admitted to our hospital because of bloody stool. Colonoscopic examination revealed hemorrhagic ulcers in the terminal ileum and a saucer-like ulcer in the cecum. Gastrointestinal endoscopy revealed several ulcerative or elevated lesions in stomach and duodenum. Biopsy specimens of these lesions and of a lymph node showed characteristic histological features of IBL-like T-cell lymphoma. The initial treatment with prednisolone (PSL) and cyclophosphamide (CPA) was effective. Six months after the treatment, however, she developed bloody stool again caused by multiple ulcerative lesions in the large intestine. The recurrence of the disease was determined histologically, and four courses of CPA, PSL, vinblastine sulfate and doxorubicin hydrochloride (CHOP) therapy were administered. One month after completing the CHOP therapy, she developed intestinal obstruction and then acute peritonitis resulting from perforation at an ulcer scar in the jejunum. Surgical treatment was successful, and histological examination demonstrated no lymphoma cells in the resected specimen. A gastrointestinal perforation should be recognized as a potential complication of IBL-like T-cell lymphoma, even during remission. (Received: June 24, 1998; accepted: Oct. 23, 1998)     

Correlation between myocardial uptake of technetium-99m-sestamibi and pressure-derived myocardial fractional flow reserve

OBJECTIVES: Development of the coronary pressure wire has facilitated the measurement of fractional flow reserve (FFR) to assess the functional severity of coronary artery stenoses. METHODS: This study evaluated the correlations between FFR and myocardial direct counts of technetium-99m(99mTc)-sestamibi in 20 patients (16 men, 4 women, mean age 66 +/- 8 years) who underwent 99mTc-sestamibi single-photon emission computed tomography (SPECT) with the 2-day protocol using 740 MBq of 99mTc-sestamibi each day. Visual assessment of myocardial imaging and quantitative analysis with the measurement of percent uptake and direct count of 99mTc-sestamibi were performed. RESULTS: Visual assessment of myocardial imaging revealed that reversibility of 99mTc-sestamibi perfusion defects was correlated with FFR of < 0.75, which is regarded as functionally important stenosis (17/20 vs 3/20, kappa = 0.71, p < 0.002). Regional reversibility score did not correlate with FFR (r = -0.40, p = NS). Quantitative analysis revealed that the change in 99mTc-sestamibi percent uptake with pharmacologic stress using adenosine triphosphate disodium (ATP) also did not correlate with FFR (r = 0.35, p = NS). In contrast, percent increase in 99mTc direct counts with ATP was lower in patients with FFR of < 0.75 than in those with FFR of > = 0.75 (-4 +/- 16% vs 24 +/- 30%, p < 0.01). In addition, a significant correlation (r = 0.70, p < 0.001) was observed between percent increase in 99mTc direct counts with ATP and FFR. CONCLUSIONS: These results suggest that quantitative analysis of 99mTc-sestamibi scintigraphy enables the assessment of the magnitude of functional significance of coronary stenosis.