Glucagon induces the plasma membrane insertion of functional aquaporin-8 water channels in isolated rat hepatocytes

Although glucagon is known to stimulate the cyclic adenosine monophosphate (cAMP)-mediated hepatocyte bile secretion, the precise mechanisms accounting for this choleretic effect are unknown. We recently reported that hepatocytes express the water channel aquaporin-8 (AQP8), which is located primarily in intracellular vesicles, and its relocalization to plasma membranes can be induced with dibutyryl cAMP. In this study, we tested the hypothesis that glucagon induces the trafficking of AQP8 to the hepatocyte plasma membrane and thus increases membrane water permeability. Immunoblotting analysis in subcellular fractions from isolated rat hepatocytes indicated that glucagon caused a significant, dose-dependent increase in the amount of AQP8 in plasma membranes (e.g., 102% with 1 micromol/L glucagon) and a simultaneous decrease in intracellular membranes (e.g., 38% with 1 micromol/L glucagon). Confocal immunofluorescence microscopy in cultured hepatocytes confirmed the glucagon-induced redistribution of AQP8 from intracellular vesicles to plasma membrane. Polarized hepatocyte couplets showed that this redistribution was specifically to the canalicular domain. Glucagon also significantly increased hepatocyte membrane water permeability by about 70%, which was inhibited by the water channel blocker dimethyl sulfoxide (DMSO). The inhibitors of protein kinase A, H-89, and PKI, as well as the microtubule blocker colchicine, prevented the glucagon effect on both AQP8 redistribution to hepatocyte surface and cell membrane water permeability. In conclusion, our data suggest that glucagon induces the protein kinase A and microtubule-dependent translocation of AQP8 water channels to the hepatocyte canalicular plasma membrane, which in turn leads to an increase in membrane water permeability. These findings provide evidence supporting the molecular mechanisms of glucagon-induced hepatocyte bile secretion.     

Biochemical and immunohistochemical analysis of glycosaminoglycans in inflamed and non-inflamed intestinal mucosa of patients with Crohn’s disease

OBJECTIVES: Changes in extracellular matrix glycosaminoglycans (GAGs) of the intestinal mucosa have been associated with inflammatory bowel disease. The aim of the present study was to follow the changes in GAGs metabolism during the progression from non-inflamed to inflamed intestinal colon of patients with Crohn's disease (CD), using direct biochemical analysis and specific immunohistochemistry against chondroitin/dermatan sulfate and heparan sulfate. DESIGN AND METHODS: The content of GAGs from inflamed and non-inflamed colon of eight patients with active CD was estimated by uronic acid per dry weight of tissue and analyzed by agarose gel electrophoresis and ion-exchange chromatography. Intestinal sections were stained using antibodies against dermatan sulfate/chondroitin 4-sulfate (DS/CS), heparan sulfate (HS), and ICAM-1 (CD54), and analyzed by confocal microscopy. RESULTS: There was a reduction in the amount of GAGs in the non-inflamed colon of patients with CD. In the inflamed colon, HS, CS and DS showed increased concentrations compared with the non-inflamed colon. GAGs showed a diffuse distribution in the lamina propria and in the basement membrane of both inflamed and non-inflamed mucosa of patients with CD. CONCLUSION: We observed a marked reduction in GAGs with altered patterns of distribution in the non-inflamed colon of patients with CD. The increase in the synthesis of GAGs observed in the inflamed colon may be a compensatory mechanism for the restoration of the integrity of the intestinal mucosa.     

The Italian Implantable Cardioverter-Defibrillator Registry. A survey of the national activity during the years 2001-2003.

BACKGROUND: In recent years several trials demonstrated the efficacy of implantable cardioverter-defibrillator (ICD) therapy for sudden cardiac death prevention and total mortality reduction in particular high-risk groups of patients. The aim of this review was to report the main epidemiological data and the most important clinical characteristics of patients enrolled in the Italian ICD Registry in the years 2001-2003. METHODS: The Italian ICD Registry--official member of the Italian Association of Arrhythmology and Cardiac Pacing (AIAC)--collects 85% of the data concerning the national ICD implantation activity, based on the European Implantable Defibrillator form (EURID). Data are validated for quality of information and uniqueness at the moment of data entry and in successive steps at the time of the annual analysis. RESULTS: The number of ICDs implanted in Italy has been continuing to increase during the last years according to the general trend in European and non-European countries: 2400 in the year 2001, 3934 in the year 2002, and 5318 in the year 2003. The number of ICDs per million of inhabitants in Italy was 42.1 in the year 2001 (+11.8% with respect to 2000), 69.0 in the year 2002 (+63.9% with respect to 2001), and 93.3 in the year 2003 (+35.2% with respect to 2002). The number of implanting centers increased progressively from 273 in the year 2001 to 304 in the year 2002, and 340 in the year 2003. The median age of patients treated with ICD implantation was 67 years in the years 2001-2002, 68 years in the year 2003. The prevalence of male patients was significantly higher (79.3% in 2001, 82.3% in 2002, and 81.4% in 2003). The main indication was syncope (25.5, 29.3, and 32.9% in the years 2001, 2002, and 2003, respectively), followed by palpitations (17.7, 18.5, and 16.4% in the years 2001, 2002, and 2003, respectively), and cardiac arrest (10.0, 13.1, and 16.5% in the years 2001, 2002, and 2003, respectively). The use of ICD in patients considered at risk but without history of sustained ventricular tachycardia had a 3-fold increase during the 3 years, from 6.4% in 2001 to 18.2% in 2003. Ventricular tachycardia was the main arrhythmia in 50.4 to 55.0% of cases, ventricular fibrillation in 13.5 to 18.1%, both in 4.1 to 6.5%. The vast majority of patients presented at the enrolment either a mild or severe reduction in ejection fraction (30 to 50%, < 30%). Amiodarone was administered alone or in combination with antiarrhythmics in 29.7 to 40.0% of patients. Single-chamber ICDs were implanted in the years 2002 and 2003 in 45.7 and 39.2% of patients, dual-chamber ICDs in 34.9 and 32.4%, biventricular ICDs in 19.4 and 28.4%, respectively. CONCLUSIONS: The ICD implantation rate in Italy increased significantly in the period 2001-2003, similarly to the trend in the other western countries and following the publication of controlled studies in the field of primary and secondary prevention of sudden cardiac death. The Italian ICD Registry showed during the last 3 years an important increase in prophylactic ICD utilization. A sophisticated ICD, including dual-chamber pacing or cardiac resynchronization therapy, was chosen in a high percentage of patients.     

Adulterants in selected dietary supplements and their detection methods

At present, there is a growing trend toward the intentional adulteration of dietary supplements (DS) with synthetic pharmaceuticals, which represents an alarming emerging risk to consumers and a serious problem for regulatory agencies. An amazing array of synthetic drugs and their analogues have been reported as adulterants in DS. Mainly, the presence of analogues represents a serious health risk as their efficacy and toxic effects have not been clinically assessed yet and may result in unpredictable adverse effects. The purpose of this review is to provide an overview, over the period 2009–2019, of the most frequently reported adulterants in DS for the treatment of erectile dysfunction, obesity/overweight, diabetes mellitus, and hypertension and the analytical methods used for their detection.     

Prefrontal Responses during Proactive and Reactive Inhibition Are Differentially Impacted by Stress in Anorexia and Bulimia Nervosa

Binge eating is a distressing, transdiagnostic eating disorder symptom associated with impulsivity, particularly in negative mood states. Neuroimaging studies of bulimia nervosa (BN) report reduced activity in frontostriatal regions implicated in self-regulatory control, and an influential theory posits that binge eating results from self-regulation failures under stress. However, there is no direct evidence that psychological stress impairs self-regulation in binge-eating disorders, or that any such self-regulatory deficits generalize to binge eating in underweight individuals (i.e., anorexia nervosa bingeing/purging subtype; AN-BP). We therefore determined the effect of acute stress on inhibitory control in 85 women (BN, 33 women; AN-BP, 22 women; 30 control participants). Participants underwent repeated functional MRI scanning during performance of the Stop-signal anticipation task, a validated measure of proactive (i.e., anticipation of stopping) and reactive (outright stopping) inhibition. Neural and behavioral responses to induced stress and a control task were evaluated on 2 consecutive days. Women with BN had reduced proactive inhibition, while prefrontal responses were increased in both AN-BP and BN. Reactive inhibition was neurally and behaviorally intact in both diagnostic groups. Both AN-BP and BN groups showed distinct stress-induced changes in inferior and superior frontal activity during both proactive and reactive inhibition. However, task performance was unaffected by stress. These results offer novel evidence of reduced proactive inhibition in BN, yet inhibitory control deficits did not generalize to AN-BP. Our findings identify intriguing alterations of stress responses and inhibitory function associated with binge eating, but they counsel against stress-induced failures of inhibitory control as a comprehensive explanation for loss-of-control eating.SIGNIFICANCE STATEMENT Binge eating is a common psychiatric syndrome that feels uncontrollable to the sufferer. Theoretically, it has been related to reduced self-regulation under stress, but there remains no direct evidence for this link in binge-eating disorders. Here, we examined how experimentally induced stress affected response inhibition in control participants and women with anorexia nervosa and bulimia nervosa. Participants underwent repeated brain scanning under stressful and neutral conditions. Although patient groups had intact action cancellation, the slowing of motor responses was impaired in bulimia nervosa, even when the likelihood of having to stop increased. Stress altered brain responses for both forms of inhibition in both groups, yet performance remained unimpaired. These findings counsel against a simple model of stress-induced disinhibition as an adequate explanation for binge eating.     

Erenumab for the preventive treatment of chronic migraine complicated with medication overuse headache: an observational,retrospective, 12-month real-life study

Background

Erenumab is a monoclonal antibody blocking the calcitonin gene–related peptide receptor, which has been approved for the preventive treatment of chronic migraine (CM). The aim of this study was to explore the safety and effectiveness of erenumab in patients suffering from CM and medication overuse headache (MOH) in a real-life setting, up to 1 year.

Methods

Data regarding 81 patients treated with erenumab were retrospectively analyzed. Every 3 months, the following variables were collected: the mean number of headache days per month (headache index (HI)), the average number of painkillers taken per month (analgesic consumption (AC)), the mean number of days with painkiller consumption (number of days on medication (NDM)), the headache intensity (numeric rating scale (NRS) score), the 6-item Headache Impact Test (HIT-6), and the Self-Reported Instrument to Assess Work-Related Difficulties in Patients With Migraine (HEADWORK) scores.

Results

The HI, AC, and NDM and the NRS, HIT-6, and HEADWORK scores were significantly lower at every time point from the 3rd month onward compared to baseline (all P < 0.0001). No significant differences were found between patients who underwent painkiller detoxification before starting erenumab and those who did not (all P > 0.05). No significant differences were found between patients taking erenumab in combination with other preventive treatments and the ones taking it alone (all P ≥ 0.05). Five patients dropped out because of adverse events, which resolved after stopping erenumab.

Conclusion

Erenumab was safe and effective for CM complicated with MOH. Painkiller withdrawal and the association with other preventive treatment(s) seem useless.

     

Larvicidal activity of lipophilic extract of Hypericum carinatum (Clusiaceae) against Aedes aegypti (Diptera: Culicidae) and benzophenones determination

In this study, the larvicidal activity of an enriched fraction of the major lipophilic phenolic compounds from Hypericum carinatum Griseb. (Clusiaceae) was investigated against larvae of Aedes aegypti (Diptera: Culicidae), the main vector of dengue virus in Brazil. The larval mortality rate ranged 37.33 to 72.00 % at concentrations of 66–200 μg/mL. The effect demonstrated to be dose-dependent. The lethal concentration 50 % and confidence interval were 100 and 88–111 μg/mL, respectively. The results could be attributed to the presence of cariphenone A and cariphenone B in concentrations of 1.24?±?0.04 and 0.56?±?0.01 %, respectively, determined by high-performance liquid chromatography. Besides, the results reinforce the potential of genus Hypericum as source of alternative insecticides.     

Multivariate analysis of the influence of peri-implant clinical parameters and local factors on radiographic bone loss in the posterior maxilla: a retrospective study on 277 dental implants

Clinical Oral Investigations - The aim of the present study was to investigate whether peri-implant clinical parameters (modified plaque index (mPI), bleeding and/or suppuration on probing (B/SOP))...