Evaluation of in-stent stenosis by magnetic resonance phase-velocity mapping in nickel-titanium stents

PURPOSE: To evaluate different grades of in-stent stenosis in a nickel-titanium stent with MRI. MATERIALS AND METHODS: Magnetic resonance phase velocity mapping (MR-PVM) was used to measure flow velocity through a 9-mm NiTi stent with three different degrees of stenosis in a phantom study. The tested stenotic geometries were 1) axisymmetric 75%, 2) axisymmetric 90%, and 3) asymmetric 50%. The MR-PVM data were subsequently compared with the velocities from computational fluid dynamic (CFD) simulations of identical conditions. RESULTS: Good quantitative agreement in velocity distribution for the 50% and 75% stenoses was observed. The agreement was poor for the 90% stenosis, most likely due to turbulence and the high-velocity gradients found in the small luminal area relative to the pixel resolution in our imaging settings. CONCLUSION: The accuracy of the MRI velocities inside the stented area renders MRI a modality that may be used to assess moderate to severe in-stent restenosis (ISR) in medium-sized vascular stents in peripheral vessels, such as the iliac, carotid, and femoral arteries. Advances in MR instrumentation may provide sufficient resolution to obtain adequate velocity information from smaller vessels, such as the coronary arteries, and allow MRI to substitute for invasive and expensive catheterization procedures currently in clinical use.     

Erk pathways negatively regulate matrix mineralization

Skeletal mineralization is an important step regulating the mechanical properties of the calcified tissues, but molecular events underlying mineralization still remain elusive. We examined the role of extracellular signal-regulated kinase (Erk) pathways in matrix mineralization of osteogenic cells both in vitro and in vivo. Matrix mineralization by preosteocytic MLO-A5 cells and osteoblastic MC3T3-E1 cells was increased by either PD98059 Mek inhibitor treatment or adenovirus vector-mediated dominant negative Ras (Ras(DN)) expression and was suppressed by Erk activation by platelet-derived growth factor (PDGF) treatment or constitutively active Mek1 (Mek(CA)) expression. Administration of adenovirus vectors carrying Ras(DN) gene onto the calvaria of 1-day-old mice increased the mineralization of the tissues, while that of the Mek(CA) adenovirus suppressed it. These results suggest that the Erk pathway is a negative regulator of the matrix mineralization both in vitro and in vivo.     

Prognostic Factors in Endodontic Surgery Using an Endoscope: A 1 Year Retrospective Cohort Study

This retrospective study clarified the success rate of endoscopic endodontic surgeries and identified predictors accounting for successful surgeries. In this retrospective study, 242 patients (90 males, 152 females) who underwent endoscopic endodontic surgery at a single general hospital and were diagnosed through follow-up one year later were included. Risk factors were categorized into attributes, general health, anatomy, and surgery. Then, the correlation coefficient was calculated for the success or failure of endodontic surgery for each variable, the odds ratio was calculated for the upper variable, and factors related to the surgical prognosis factor were identified. The success rate of endodontic surgery was 95.3%, showing that it was a highly predictable treatment. The top three correlation coefficients were post, age, and perilesional sclerotic signs. Among them, the presence of posts was the highest, compared with the odds ratio, which was 9.592. This retrospective study revealed the success rate and risk factors accounting for endoscopic endodontic surgeries. Among the selected clinical variables, the presence of posts was the most decisive risk factor determining the success of endodontic surgeries.     

Correlation between a Bedridden Status and the Long-term Outcome in Hemodialysis Patients after Intracerebral Hemorrhaging

Objective The quality of life and activities of daily living (ADL) are generally poor among dialysis patients after intracerebral hemorrhaging, and their precise clinical course remains unclear. In addition, the association between the severity of cerebral hemorrhaging and the long-term prognosis in these patients has not been fully elucidated. This study aimed to evaluate the subsequent prognosis of hemodialysis patients who survived the acute phase of intracerebral hemorrhaging. Methods We included hemodialysis patients who were admitted to Nagasaki University Hospital between 2007 and 2015 for intracerebral hemorrhaging treatment. After excluding cases of in-hospital death, survivors were classified using the 5-point modified Rankin Scale (mRS), which specifically measures the ADL in patients with cerebrovascular diseases. The patients were followed up at the medical facilities to which they were transferred in the same medical zone until 2017. Results Out of 91 patients with cerebral hemorrhaging (65±11 years old, 66% men, hemodialysis duration 108±91 months), 62 survived until discharge. Twenty-one patients died during observation, largely due to infectious diseases, such as sepsis and pneumonia (n=16, 76%). Compared to patients with mRS 0-4 (n=31), those with mRS 5 (n=31) showed a significantly poorer prognosis. The hazard ratio adjusted for age and antiplatelets was 13.7 (95% confidence interval: 3.88-63.7, p<0.001). Conclusion Hemodialysis patients with intracerebral hemorrhaging who were bedridden showed poor outcomes. The major causes of death were infections. Therefore, these patients should be carefully monitored for infections in order to improve their prognosis.     

Genotoxicity studies of glycidol fatty acid ester (glycidol linoleate) and glycidol

Glycidol fatty acid esters (GEs) are found in refined edible oils. Safety concerns have been alleged due to the possible release of glycidol (G), an animal carcinogen.     

Standardized uptake values of uterine leiomyoma with <Superscript>18</Superscript>F-FDG PET/CT: variation with age,size, degeneration,and contrast enhancement on MRI

OBJECTIVE: To assess the effect of age, size, the degree of degeneration, and contrast enhancement on magnetic resonance imaging (MRI) on 18F-fluoro-2-deoxyglucose (18F-FDG) uptake in uterine leiomyomas using quantitative standardized uptake values (SUVs). METHODS: A total of 61 leiomyomas of 41 patients, who underwent combined positron emission tomography/computed tomography (PET/CT) using 18F-FDG and contrast-enhanced MRI were included in this study. Sixty-one leiomyomas were divided into two groups: "non-degenerated" leiomyomas showing distinct low signal intensity on T2-weighted images and intermediate signal intensity on T1-weighted images, and "degenerated" leiomyomas showing other types of signal intensity. Sixty-one leiomyomas were also divided into two groups of "strongly enhancing" leiomyomas and "weakly enhancing" leiomyomas in terms of their degree of contrast enhancement on MRI. RESULTS: The mean values of the maximum and average SUVs for the total of 61 leiomyomas were 2.34 +/- 0.75 (range 1.59-5.15) and 1.74 +/- 0.50 (0.66-3.95), respectively. There was a moderate negative correlation between the maximum and average SUVs and age (r = -0.43 and P = 0.00016, r = -0.31 and P = 0.029, respectively). Although there was a mild positive correlation between maximum SUV and size (r = 0.35 and P = 0.011), there was no significant difference between average SUV and size. Although there was no significant difference in average SUV between "degenerated" and "non-degenerated" leiomyomas, the maximum SUV of "degenerated" leiomyomas was significantly higher than that of "non-degenerated" leiomyomas (P = 0.0012). The degree of contrast enhancement on MRI was not significantly correlated with 18F-FDG uptake. CONCLUSIONS: Mild or moderate uptake of 18F-FDG is often observed in uterine leiomyoma and declines with age, and should not be confused with malignant accumulation.     

Assessment of ascending aorta using epiaortic ultrasonography during off-pump coronary artery bypass grafting

BACKGROUND: Use of an aortic partial clamp for proximal anastomosis during off-pump coronary artery bypass is known to increase the risk of fatal complications. The purpose of this study was to assess the management of the ascending aorta evaluated with epiaortic ultrasonography during off-pump coronary artery bypass. METHODS: Intraoperative ultrasonography of the ascending aorta with a 10-MHz probe was performed consecutively in 155 patients undergoing off-pump coronary artery bypass between August 1999 and July 2001. The findings from ultrasonography, surgical modifications, and operative results were analyzed. RESULTS: In 54 patients (34.8%), epiaortic ultrasonography showed atherosclerotic findings in the anterior side of the ascending aorta (group A). The remaining 101 patients had either normal findings or atherosclerotic findings in only the posterior side (group NA). A proximal anastomosis to the aorta was preoperatively planned in 117 patients (group A, 42; group NA, 75). In group A, a graft modification without clamping was implemented in 29 patients (24.8% of 117 patients), whereas the clamp site was modified to a different segment in 13 patients (11.1% of 117 patients). In all 75 patients in group NA, partial clamping was used in the standard fashion. There were no cerebral infarctions or operative deaths related to partial clamping. However, aortic dissection occurred in 1 patient in group NA. CONCLUSIONS: In 35% of patients undergoing off-pump coronary artery bypass, epiaortic ultrasonography identified atherosclerotic findings in the anterior wall of the ascending aorta. This study suggests that revascularization without aortic manipulation during off-pump coronary artery bypass is indicated in as many as 25% of patients.     

Glucagon acutely inhibits but chronically activates Na(+)/H(+) antiporter 3 activity in OKP cells.

BACKGROUND: We previously found that the Na(+)/H(+) exchanger 3 (NHE3) is localized in the apical membrane of the rat renal proximal tubule and thick ascending limb of Henle. In the present study, we examined the direct effect of glucagon on the opossum kidney P (OKP) cell Na(+)/H(+) antiporter, encoded by NHE3. METHODS: Na(+)/H(+) antiporter activity was measured as the rate of cell pH recovery from an acid load using 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein. Northern blot and Western blot analyses were performed using OKP NHE3 cDNA and anti-OKP-NHE3 antibodies. RESULTS: Glucagon (1 ng/ml) acutely (1 h) inhibited, but chronically (24 h) activated NHE3 activity in OKP cells. These effects were blocked by either KT5720 or RpcAMP [protein kinase A (PKA) inhibitors], and mimicked by 10(-4) M dibutyryl-cAMP. Both NHE3 mRNA and protein abundance increased with the 24-hour incubation in glucagon or dibutyryl-cAMP. Cycloheximide did not prevent a significant increase in NHE3 activity at 24 h. We therefore examined NHE3 protein abundance in the surface membrane by the biotinylation method. cAMP or glucagon significantly increased NHE3 protein abundance in the surface membrane when incubated with cycloheximide for 24 h. CONCLUSIONS: Glucagon acutely inhibits but chronically activates NHE3 activity in OKP cells via a PKA-dependent pathway. Both protein-synthesis-dependent and -independent mechanisms play important roles in the chronic activation of NHE3.