Over-the-wire US catheter probe as an adjunct to ERCP in the detection of choledocholithiasis

BACKGROUND: Intraductal ultrasound (IDUS) as an adjunct to ERCP for detection of extrahepatic bile duct stones is technically easy, accurate, and safe. This prospective study evaluated IDUS with an "over-the-wire" catheter US probe as an adjunct to ERCP. METHODS: Sixty-five patients, highly suspected to have choledocholithiasis, underwent IDUS during ERCP. The IDUS probe was inserted by means of the duodenoscope into the bile duct without performing a sphincterotomy. All stones identified by IDUS or retrograde cholangiography were removed with either a basket or retrieval balloon after endoscopic sphincterotomy. RESULTS: The final diagnosis was choledocholithiasis in 59 patients. Bile duct diameter ranged from 0.6 to 2.3 cm and stone size from 2 mm to 2 cm. IDUS successfully identified all stones in these patients. IDUS resulted in 2 false-positive diagnoses in the remaining 6 patients without stones (overall accuracy 97%, sensitivity 100%, specificity 67%). Cholangiography detected stones in 55 of the patients with stones (accuracy 94%, sensitivity 93%, specificity 100%). CONCLUSION: IDUS, a safe, technically easy procedure, is highly accurate in the detection of extrahepatic bile duct stones regardless of the diameter of the bile ducts. The "over-the-wire" technique preserves access to the cannulated duct. IDUS is an excellent adjunct to ERCP for the diagnosis of choledocholithiasis. IDUS differentiates stones from air bubbles and prevents unnecessary sphincterotomy.     

GPCR dimerization in brainstem nuclei contributes to the development of hypertension

Background and Purpose

μ-Opioid receptors, pro-opiomelanocortin and pro-enkephalin are highly expressed in the nucleus tractus solitarii (NTS) and μ receptor agonists given to the NTS dose-dependently increased BP. However, the molecular mechanisms of this process remain unclear. In vitro, μ receptors heterodimerize with α_2A-adrenoceptors. We hypothesized that α_2A-adrenoceptor agonists would lose their depressor effects when their receptors heterodimerize in the NTS with μ receptors.

Experimental Approach

We microinjected μ-opioid agonists and antagonists into the NTS of rats and measured changes in BP. Formation of μ receptor/α_2A-adrenoceptor heterodimers was assessed with immunofluorescence and co-immunoprecipitation methods, along with proximity ligation assays.

Key Results

Immunofluorescence staining revealed colocalization of α_2A-adrenoceptors and μ receptors in NTS neurons. Co-immunoprecipitation revealed interactions between α_2A-adrenoceptors and μ receptors. In situ proximity ligation assays confirmed the presence of μ receptor/α_2A-adrenoceptor heterodimers in the NTS. Higher levels of endogenous endomorphin-1 and μ receptor/α_2A-adrenoceptor heterodimers were found in the NTS of hypertensive rats, than in normotensive rats. Microinjection of the μ receptor agonist [D-Ala², MePhe⁴, Gly⁵-ol]-enkephalin (DAMGO), but not that of the α_2A-adrenoceptor agonist guanfacine, into the NTS of normotensive rats increased μ receptor/α_2A-adrenoceptor heterodimer formation and BP elevation. The NO-dependent BP-lowering effect of α_2A-adrenoceptor agonists was blunted following increased formation of μ receptor/α_2A-adrenoceptor heterodimers in the NTS of hypertensive rats and DAMGO-treated normotensive rats.

Conclusions and Implications

Increases in endogenous μ receptor agonists in the NTS induced μ receptor/α_2A-adrenoceptor heterodimer formation and reduced the NO-dependent depressor effect of α_2A-adrenoceptor agonists. This process could contribute to the pathogenesis of hypertension.     

Activating mitochondrial function and haemoglobin expression with EH-201, an inducer of erythropoietin in neuronal cells,reverses memory impairment

Background and Purpose

Memory impairment can be progressive in neurodegenerative diseases, and physiological ageing or brain injury, mitochondrial dysfunction and oxidative stress are critical components of these issues. An early clinical study has demonstrated cognitive improvement during erythropoietin treatment in patients with chronic renal failure. As erythropoietin cannot freely cross the blood–brain barrier, we tested EH-201 (2,3,5,4′-tetrahydroxystilbene-2-O-β-d-glucoside, also known as TSG), a low MW inducer of erythropoietin, for its therapeutic effects on memory impairment in models of neurodegenerative diseases, physiological ageing or brain injury.

Experimental Approach

The effects of EH-201 were investigated in astrocytes and PC12 neuronal-like cells. In vivo, we used sleep-deprived (SD) mice as a stress model, amyloid-β (Aβ)-injected mice as a physiological ageing model and kainic acid (KA)-injected mice as a brain damage model to assess the therapeutic effects of EH-201.

Key Results

EH-201 induced expression of erythropoietin, PPAR-γ coactivator 1α (PGC-1α) and haemoglobin in astrocytes and PC12 neuronal-like cells. In vivo, EH-201 treatment restored memory impairment, as assessed by the passive avoidance test, in SD, Aβ and KA mouse models. In the hippocampus of mice given EH-201 in their diet, levels of erythropoietin, PGC-1α and haemoglobin were increased

Conclusions and Implications

The induction of endogenous erythropoietin in neuronal cells by inducers such as EH-201 might be a therapeutic strategy for memory impairment in neurodegenerative disease, physiological ageing or traumatic brain injury.     

Betulinic acid exerts anti-hepatitis C virus activity via the suppression of NF-κB- and MAPK-ERK1/2-mediated COX-2 expression

Background and Purpose

This study was designed to evaluate the effect of betulinic acid (BA), extracted from Avicennia marina, on the replication of hepatitis C virus (HCV) and to investigate the mechanism of this BA-mediated anti-HCV activity.

Experimental Approach

HCV replicon and infectious systems were used to evaluate the anti-HCV activity of BA. Exogenous COX-2 or knock-down of COX-2 expression was used to investigate the role of COX-2 in the anti-HCV activity of BA. The effects of BA on the phosphorylation of NF-κB and on kinases in the MAPK signalling pathway were determined. The anti-HCV activity of BA in combination with other HCV inhibitors was also determined to assess its use as an anti-HCV supplement.

Key Results

BA inhibited HCV replication in both Ava5 replicon cells and in a cell culture-derived infectious HCV particle system. Treatment with a combination of BA and IFN-α, the protease inhibitor telaprevir or the NS5B polymerase inhibitor sofosbuvir resulted in the synergistic suppression of HCV RNA replication. Exogenous overexpression of COX-2 gradually attenuated the inhibitory effect of BA on HCV replication, suggesting that BA reduces HCV replication by suppressing the expression of COX-2. In particular, BA down-regulated HCV-induced COX-2 expression by reducing the phosphorylation of NF-κB and ERK1/2 of the MAPK signalling pathway.

Conclusions and Implications

BA inhibits HCV replication by suppressing the NF-κB- and ERK1/2-mediated COX-2 pathway and may serve as a promising compound for drug development or as a potential supplement for use in the treatment of HCV-infected patients.     

Emphysematous pyelonephritis: clinicoradiological classification, management, prognosis, and pathogenesis

BACKGROUND: Emphysematous pyelonephritis (EPN) is a rare, severe gas-forming infection of renal parenchyma and its surrounding areas. The radiological classification and adequate therapeutic regimen are controversial and the prognostic factors and pathogenesis remain uncertain. OBJECTIVES: To elucidate the clinical features, radiological classification, and prognostic factors of EPN; to compare the modalities of management (ie, antibiotic treatment alone, percutaneous catheter drainage combined with antibiotic treatment, or nephrectomy) and outcome among the various radiological classes of EPN; and to clarify the gas-forming mechanism and pathogenesis of EPN by gas analysis and pathological findings. PATIENTS AND METHODS: Forty-eight EPN cases from our institution were enrolled between August 1,1989, and November 30, 1997. According to the radiological findings on computed tomographic scan, they were classified into the following classes: (1) class 1: gas in the collecting system only; (2) class 2: gas in the renal parenchyma without extension to extrarenal space; (3) class 3A: extension of gas or abscess to perinephric space; class 3B: extension of gas or abscess to pararenal space; and (4) class 4: bilateral EPN or solitary kidney with EPN. The clinical manifestations, management, and outcome were compared. The gas contents of specimens from 6 patients were analyzed. The pathological findings from 8 patients who received nephrectomy were reviewed. The statistical methods consisted of the Fisher exact test (2 tailed) for categorical variables and Wilcoxon rank sum test for continuous variables to test the predictors of poor prognosis. RESULTS: Forty-six patients (96%) had diabetes mellitus, and 10 (22%) of the 46 also had urinary tract obstruction in the corresponding renoureteral unit. The other 2 nondiabetic patients (4%) had severe hydronephrosis. Twenty-one (72%) of the 29 patients with diabetes mellitus also had a glycosylated hemoglobin A(1c) level higher than 0.08. Escherichia coli (69%) and Klebsiella pneumoniae (29%) were the most common pathogens. The mortality rate in patients who received antibiotic treatment alone was 40% (2 of 5 patients). The success rate of management by percutaneous catheter drainage (PCD) combined with antibiotic treatment was 66% (27 of 41 patients). In classes 1 and 2 EPN, all the patients who were treated using a PCD or ureteral catheter combined with antibiotic treatment survived. In extensive EPN (classes 3 and 4), 17 (85%) of the 20 patients with fewer than 2 risk factors (ie, thrombocytopenia, acute renal function impairment, disturbance of consciousness, or shock) were successfully treated using PCD combined with antibiotic treatment; and the patients with 2 or more risk factors had a significantly higher failure rate than those with no or only 1 risk factors (92% vs 15%, P<.001). Eight of the 14 patients who had an unsuccessful treatment using a PCD underwent subsequent nephrectomy, 7 of whom survived. Only 2 patients were managed by direct nephrectomy and survived. The overall success rate of nephrectomy was 90% (9 of 10 patients). The total mortality was 18.8% (9 of 48 patients). Five of the 6 gas samples contained hydrogen (average, 12.8%), and all had carbon dioxide (average, 14.4%). The pathological findings from 8 of 10 who underwent nephrectomy revealed poor perfusion in most cases (ie, infarction, 5 patients; vascular thrombosis, 3 patients; and arteriosclerosis and/or glomerulosclerosis, 4 patients). CONCLUSION: Acute renal infection with E coli or K pneumoniae in patients with diabetes mellitus and/or urinary tract obstruction is the cornerstone for the development of EPN. Mixed acid fermentation of glucose by Enterobacteriaceae is the major pathway of gas formation. For localized EPN (classes 1 and 2), PCD combined with antibiotic treatment can provide a good outcome. (ABSTRACT TRUNCATED)     

Distinct regulations by calcium of cyclic GMP levels and catecholamine secretion in isolated bovine adrenal chromaffin cells

The effects of various calcium-dependent secretagogues on cyclic GMP levels and catecholamine (CA) secretion were measured in a preparation of bovine adrenal chromaffin cells. The secretory effect of acetylcholine (ACh; 8--10 fold stimulation) was mimicked by nicotine but not muscarine. Three--five fold stimulations of cyclic GMP levels were also obtained with ACh and muscarine but not nicotine. High concentration of K+, and the ionophore A23187, also elevated cyclic GMP levels. However, secretion produced by veratridine, ouabain, and the ionophore X537A was not accompanied by any rise in cyclic GMP levels. Removal of extracellular calcium significantly decreased both basal levels of CA secretion and of cyclic GMP and completely abolished their stimulation by ACh. The half-maximal effects of calcium on the cholinergic stimulations of cyclic GMP levels and of CA secretion were observed at 0.2 and 2.5 mM, respectively. Substitution of Ca2+ by Sr2+ was more effective in maintaining the cyclic GMP response than the secretory response. The calcium channel blockers Co2+, Mg2+ and Ni2+ inhibited the cholinergic stimulation of cyclic GMP more than that of CA release. On the other hand, the organic calcium channel blockers, verapamil and methoxyverapamil (D--600) were more effective antagonists of the secretory response. These data indicate that the cholinergic stimulations of CA secretion and of cyclic GMP levels in bovine adrenal chromaffin cells are regulated by calcium via two distinct mechanisms.     

A NOD2-NALP1 complex mediates caspase-1-dependent IL-1beta secretion in response to Bacillus anthracis infection and muramyl dipeptide

NOD2, a NOD-like receptor (NLR), is an intracellular sensor of bacterial muramyl dipeptide (MDP) that was suggested to promote secretion of the proinflammatory cytokine IL-1beta. Yet, the molecular mechanism by which NOD2 can stimulate IL-1beta secretion, and its biological significance were heretofore unknown. We found that NOD2 through its N-terminal caspase recruitment domain directly binds and activates caspase-1 to trigger IL-1beta processing and secretion in MDP-stimulated macrophages, whereas the C-terminal leucine-rich repeats of NOD2 prevent caspase-1 activation in nonstimulated cells. MDP challenge induces the association of NOD2 with another NLR protein, NALP1, and gel filtration analysis revealed the formation of a complex consisting of NOD2, NALP1, and caspase-1. Importantly, Bacillus anthracis infection induces IL-1beta secretion in a manner that depended on caspase-1 and NOD2. In vitro, Anthrax lethal toxin strongly potentiated IL-1beta secretion, and that response was NOD2 and caspase-1-dependent. Thus, NOD2 plays a key role in the B. anthracis-induced inflammatory response by being a critical mediator of IL-1beta secretion.     

Effect of relaxin on aromatase activity in human endometrial stromal cells

Previous studies have shown that the aromatase activity in human endometrial stromal cells was stimulated by progestin and enhanced by estrogen and forskolin (Fk), an agent that stimulates the accumulation of intracellular cAMP. Present study was undertaken to investigate whether any peptide hormone would affect endometrial aromatase activity. Stromal cells were isolated from normal proliferative and secretory endometria and cultured in nutrient medium. Porcine relaxin (RLX) was added to culture medium individually or in combination with medroxyprogesterone acetate (MPA) and estradiol (E2). Cells treated with RLX alone did not affect the aromatase activity. RLX, however, exerted a synergistic effect on aromatase activity in the presence of MPA or MPA plus E2. On the other hand, human CG, epidermal growth factor, human PRL, and insulin did not increase the aromatase activity in the presence or absence of MPA and E2 studied in a limited number of specimens. The progestin-dependent effect of RLX on aromatase activity was dose dependent indicating that the biological effect of RLX is mediated through a saturable mechanism. When RLX was added to MPA-pretreated cells, additional increase of aromatase activity was seen after 24 h incubation indicating that the action of RLX on stromal cells is not an acute effect. Antiprogestin, RU486, inhibited the stimulation of aromatase activity in both MPA and MPA plus RLX treated cells. RLX has either no effect or a moderate increase (up to 2-fold over the control) on intracellular cAMP content. On the other hand, Fk increased the intracellular cAMP level and enhanced the aromatase activity in the presence of progestin. Also RLX did not replace the effect of Fk since additional increase of aromatase activity was noted when stromal cells were incubated with MPA plus RLX plus Fk in comparison to MPA plus RLX or MPA plus Fk. These results suggest that the action of RLX on stromal cells may be mediated through an intracellular messenger independent of cAMP. Present studies provide evidence that RLX exerts a synergistic effect on aromatase activity in the presence of progestin in human endometrial stromal cells. It is evident that human endometrium is a target organ of RLX.     

Renin-angiotensin system component expression in the HL-1 atrial cell line and in a pig model of atrial fibrillation

OBJECTIVES: Local atrial tissue angiotensin II (AngII) level is elevated in atrial fibrillation (AF), but the mechanism is unknown. We hypothesized that atrial myocytes express all components of the renin-angiotensin system (RAS) and investigated whether rapid depolarization alone is sufficient to increase paracrine AngII production by up-regulating RAS component expression. METHODS: In the HL-1 atrial cell line, rapid depolarization was induced by rapid field electrical stimulation (RES) at 1.0 V/cm and 600/min (10 Hz) in atrial HL-1 cells. In a pig model of AF, AF was induced by atrial pacing at 600/min in 10 adult pigs and 10 sham-operated pigs for comparison. RESULTS: In atrial myocytes, RES induced a sustained elevation of intracellular calcium, and up-regulation of angiotensin-converting enzyme (ACE), chymase and angiotensinogen, resulting in increased AngII production. RES-induced AngII production was attenuated by enalapril [ACE inhibitor (ACEI)] and chymostatin (chymase inhibitor). Conditioned medium from RES-stimulated atrial myocytes increased [3H]leucine uptake and atrial natriuretic peptide expression in atrial myocytes, and [3H]proline uptake and collagen type 1 alpha 1 expression in atrial fibroblasts. Both were attenuated by co-incubation with the AngII type 1 receptor blocker (ARB) losartan. In the porcine model, significant structural changes and a similar pattern of changes of RAS components were noted in AF pigs. CONCLUSIONS: Atrial cells expressed all components of RAS and rapid depolarization alone was sufficient to up-regulate RAS components, increase paracrine AngII production and induce atrial structural changes, which are attenuated by ACEI, ARB and chymase inhibitor.     

Association of the human minK gene 38G allele with atrial fibrillation: evidence of possible genetic control on the pathogenesis of atrial fibrillation

Background Human minK protein is the β-subunit of I_Ks potassium channel and plays an important role in cardiac cellular electrophysiology. We investigated the association between human atrial fibrillation and the polymorphism of minK gene (38G or 38S) with a case-control study. Methods We included 108 patients with atrial fibrillation and 108 control subjects. The case patients and control subjects were matched regarding age, sex, presence of valvular heart disease, and presence of left ventricular dysfunction. The genotype of minK was determined with polymerase chain reaction and restriction fragment analysis. Results The results showed an association between the minK 38G allele and atrial fibrillation. The odds ratios for atrial fibrillation in patients with 1 and 2 minK 38G alleles were 2.16 (95% CI 0.81-5.74) and 3.58 (95% CI 1.38-9.27), respectively, when compared with patients without minK 38G allele. In a logistic regression model, the odds ratio for atrial fibrillation was 1.80 (95% CI 1.20-2.71, P < .0046) for patients with 1 more minK 38G allele. Conclusion We report the association between the minK 38G allele and clinical atrial fibrillation. Our findings suggest possible genetic control on the pathogenesis of atrial fibrillation. (Am Heart J 2002;144:485-90.)