Impact of device-host interaction on paravalvular aortic regurgitation with different transcatheter heart valves

Aims

We sought to evaluate the interaction of different aortic root phenotypes with self-expanding (SEV), balloon-expandable (BEV) and mechanically expanded (MEV) and the impact on significant aortic regurgitation.

Decreased intracellular calcium mediates the histamine H3-receptor-induced attenuation of norepinephrine exocytosis from cardiac sympathetic nerve endings

Activation of presynatic histamine H(3) receptors (H(3)R) down-regulates norepinephrine exocytosis from cardiac sympathetic nerve terminals, in both normal and ischemic conditions. Analogous to the effects of alpha(2)-adrenoceptors, which also act prejunctionally to inhibit norepinephrine release, H(3)R-mediated antiexocytotic effects could result from a decreased Ca(2+) influx into nerve endings. We tested this hypothesis in sympathetic nerve terminals isolated from guinea pig heart (cardiac synaptosomes) and in a model human neuronal cell line (SH-SY5Y), which we stably transfected with human H(3)R cDNA (SH-SY5Y-H(3)). We found that reducing Ca(2+) influx in response to membrane depolarization by inhibiting N-type Ca(2+) channels with omega-conotoxin (omega-CTX) greatly attenuated the exocytosis of [(3)H]norepinephrine from both SH-SY5Y and SH-SY5Y-H(3) cells, as well as the exocytosis of endogenous norepinephrine from cardiac synaptosomes. Similar to omega-CTX, activation of H(3)R with the selective H(3)R-agonist imetit also reduced both the rise in intracellular Ca(2+) concentration (Ca(i)) and norepinephrine exocytosis in response to membrane depolarization. The selective H(3)R antagonist thioperamide prevented this effect of imetit. In the parent SH-SY5Y cells lacking H(3)R, imetit affected neither the rise in Ca(i) nor [(3)H]norepinephrine exocytosis, demonstrating that the presence of H(3)R is a prerequisite for a decrease in Ca(i) in response to imetit and that H(3)R activation modulates norepinephrine exocytosis by limiting the magnitude of the increase in Ca(i). Inasmuch as excessive norepinephrine exocytosis is a leading cause of cardiac dysfunction and arrhythmias during acute myocardial ischemia, attenuation of norepinephrine release by H(3)R agonists may offer a novel therapeutic approach to this condition.     

Transfer of an ampicillin resistance gene between two Escherichia coli strains in the bowel microbiota of an infant treated with antibiotics

OBJECTIVES: To investigate the presumed acquisition of ampicillin resistance by an Escherichia coli strain residing in the gut of an infant. METHODS: E. coli strains were quantified in faecal samples obtained at regular intervals from an infant followed from birth to 12 months of age and their resistance profiles were determined. beta-Lactamases were identified by isoelectric focusing and genes by PCR followed by DNA sequencing. Plasmids were characterized by restriction fragment analysis and Southern-blot hybridization, and tested for conjugative transfer. RESULTS: The infant carried two E. coli strains, termed 29A and 29B, simultaneously in the microbiota during the first month of life. All isolates of 29A were resistant to ampicillin, whereas strain 29B, which was initially ampicillin susceptible, acquired resistance following treatment of the infant with ampicillin/amoxicillin because of urinary tract infection. Acquisition of resistance by strain 29B was associated with acquisition of a bla(TEM-1b)-encoding plasmid, pNK29, which was also present in strain 29A. Transfer of plasmid pNK29 could be replicated by conjugation from strain 29A to strain 29B in vitro. Strain 29A also adapted to ampicillin treatment by mutation of the bla(TEM-1b) promoter gene to yield a higher level of resistance. CONCLUSIONS: This is an unequivocal demonstration of gene transfer between two strains co-residing in the human gut, as the donor, recipient and transconjugant strains were isolated. The results suggest the dynamic adaptation by commensal bacteria in response to antibiotic treatment may occur readily.     

Multifidus muscle size in adolescents with and without back pain using ultrasonography

Objective

The purposes of this study were; a) to compare multifidus muscle cross sectional area (CSA) in male adolescents suffering from low back pain (LBP) with healthy male adolescents using ultrasonography (US), and b) to assess the correlation between multifidus muscle size and demographic variables.

Endoscopic ultrasonography (EUS) in the localization of insulinoma

Objective Endoscopic ultrasonography has been accepted as a sensitive modality for preoperative tumor localization in pancreas. We have aimed to determine the performance characteristics of endoscopic ultrasonography in pancreatic insulinoma localization and evaluation of relationship between the tumor size and serum-c peptide level, lowest glucose level and insulin level. Methods Patients suspicious to insulinoma according to clinical and laboratory findings were included. Endoscopic ultrasonography was performed and if a tumor was identified, the patient was referred for surgery. Results A total of 52 patients (24 male and 28 female) with mean age of 42.4 years underwent EUS and 43 patients underwent surgery. In one patient, a tumor was identified both by transabdominal ultrasonography and abdominal CT scan. The overall sensitivity and accuracy of endoscopic ultrasonography for detection of insulinoma was 89.5% and 83.7% respectively. The sensitivity of endoscopic ultrasonography for detection of lesions in pancreatic head, body and tail was 92.6%, 78.9%, and 40.0%, respectively. There was no relationship between c-peptide, lowest blood glucose, insulin blood levels and tumor size in surgery. Conclusion EUS is an accurate method for detection of insulinoma. The accuracy depends on the location of the tumor and is greatest for tumors in the pancreatic head.     

Cardiac mast cell-derived renin promotes local angiotensin formation, norepinephrine release, and arrhythmias in ischemia/reperfusion

Having identified renin in cardiac mast cells, we assessed whether its release leads to cardiac dysfunction. In Langendorff-perfused guinea pig hearts, mast cell degranulation with compound 48/80 released Ang I-forming activity. This activity was blocked by the selective renin inhibitor BILA2157, indicating that renin was responsible for Ang I formation. Local generation of cardiac Ang II from mast cell-derived renin also elicited norepinephrine release from isolated sympathetic nerve terminals. This action was mediated by Ang II-type 1 (AT1) receptors. In 2 models of ischemia/reperfusion using Langendorff-perfused guinea pig and mouse hearts, a significant coronary spillover of renin and norepinephrine was observed. In both models, this was accompanied by ventricular fibrillation. Mast cell stabilization with cromolyn or lodoxamide markedly reduced active renin overflow and attenuated both norepinephrine release and arrhythmias. Similar cardioprotection was observed in guinea pig hearts treated with BILA2157 or the AT1 receptor antagonist EXP3174. Renin overflow and arrhythmias in ischemia/reperfusion were much less prominent in hearts of mast cell-deficient mice than in control hearts. Thus, mast cell-derived renin is pivotal for activating a cardiac renin-angiotensin system leading to excessive norepinephrine release in ischemia/reperfusion. Mast cell-derived renin may be a useful therapeutic target for hyperadrenergic dysfunctions, such as arrhythmias, sudden cardiac death, myocardial ischemia, and congestive heart failure.     

Nonlinear photoresponse of NaYF4:Yb,Er@NaYF4 nanocrystals under green CW excitation: a comprehensive study

One of the efficient and well-known upconverting nanomaterials is NaYF₄:Yb,Er@NaYF₄, which emits photoluminescence at 545 nm and 660 nm under an excitation of 980 nm. Here, the nonlinearity of β-NaYF₄:Yb,Er@NaYF₄ at 532 nm is investigated using three nonlinear approaches. For the first time, the nonlinear optical conjugation of NaYF₄:Yb,Er@NaYF₄ nanocrystals is observed using the degenerate four-wave mixing method. In the optical bistability study, the optical hysteresis of NaYF₄:Yb,Er@NaYF₄ is measured using the Mach–Zehnder interferometer nonlinear ring cavity, and the results of bistability loops show different behaviors at different power regimes. Finally, the Z-scan technique is used for determining the nonlinear absorption and refraction coefficients, which are calculated in the order of 10⁻⁴ (cm W⁻¹) and 10⁻⁸ (cm² W⁻¹), respectively. The results indicate that by increasing incident powers, optical behaviour changes in both optical bistability and Z-scan. Therefore, the results exhibit that the β-NaYF₄:Yb,Er@NaYF₄ nanocrystals have nonlinear photoresponses at both 980 and 532 nm, which could be promising for photonic devices based on NIR light and visible light.

NaYF₄:Yb,Er@NaYF₄ is an efficient and well-known upconverting nanomaterials at 980 nm, also it has strong optical nonlinearity at 532 nm related to energy states of the Yb/Er system which is determined by a unique approach.     

Systemic lupus erythematosus in Iran: a study of 2280 patients over 33 years

Objective: Systemic lupus erythematosus (SLE) as a chronic autoimmune disease has a worldwide distribution. There is a wide variation in the natural history of SLE among different ethnic and geographic groups. The aim of this study was to show the manifestations of SLE in Iranian patients. Methods: The study was on manifestations of SLE according to the database of the Rheumatology Research Center (RRC), Tehran, Iran, on registered patients during the period of 1976 to 2009. Results: A total of 2280 SLE patients (2052 female and 228 male) were studied. The female : male ratio was 9 : 1 and the mean age at presentation was 24.4 ± 10.4 years. Prevalence of manifestations included: musculoskeletal (83.2%), cutaneous (81.1%), renal (65.4%), neuropsychiatric (23.4%), pulmonary (21.5%), cardiac (17.2%), and hematologic (66.4%) symptoms. There was positive antinuclear antibodies in 86.4% and anti‐DNA in 82.3% of patients. Overlap syndrome and positive family history with other autoimmune diseases were detected in 7.6% and 3.4% of patients, respectively. Conclusion: In our patients the prevalence of cutaneous involvement was similar to those of nearby countries (with similar climate). Renal involvement was seen more than some other countries especially more than European countries, while other manifestations (such as hematologic and joint involvement) were similar to European countries (with similar ethnicity). We may conclude that genetic and/or climatic factors may lead to different presentations of lupus.     

Liver Histology Changes in Nonalcoholic Steatohepatitis after One Year of Treatment with Probucol

BACKGROUND: Probucol, a lipid-lowering agent with antioxidant effects, is effective in normalizing liver enzymes in patients with nonalcoholic steatohepatitis (NASH). We studied changes in the liver histology of patients with NASH after use of probucol for one year. METHODS: Ten patients with biopsy-proven NASH were included. Subjects were given 500 mg probucol daily. Liver biopsies were performed before treatment and after one year. RESULTS: Eight patients completed treatment. The mean alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels decreased from 94 and 55 to 41 and 26, respectively (P = 0.004 and 0.001 respectively). The scores for hepatic steatosis and necroinflammation decreased from 7.4 to 5.6 (P = 0.03). The fibrosis score changed from 1.1 to 1.3 (P = 0.79). No adverse drug effects were observed. CONCLUSION: Probucol is effective in normalizing aminotransferase levels in patients with NASH. It also significantly reduces the histology grade of steatohepatitis after one year of treatment.