Guidelines for the Perplexed: How to Maximize Colonoscopy Efficiency During the COVID-19 Pandemic

Digestive Diseases and Sciences -     

Rifabutin as salvage therapy for Helicobacter pylori eradication: Cornerstones and novelties

When several Helicobacter pylori eradication treatments fail, guidelines recommend a cultured guided approach; however, culture is not widely available. Therefore, a rifabutin based regimen could be the best solution. Rifabutin indeed shows a low rate of antibiotic resistance. Rifabutin is generally used in combination with amoxicillin in a triple therapy, with eradication rates about 80% in third-line regimens. The ideal duration of this therapy should range between 10 and 12 d. Combinations with antibiotics other than amoxicillin have demonstrated even better results, such as vonoprazan, which is a type of novel acid suppressor drug. Finally, a new formulation of triple therapy in a single capsule is under investigation, which is a field that deserves further investigation. Some notes of caution about rifabutin should be mentioned. This drug is used to treat tuberculosis or atypical mycobacteria; therefore, before starting a rifabutin-based eradication regimen, Mycobacterium tuberculosis infection should be thoroughly tested, since its use could promote the development of antibiotic resistance, thus affecting its effectiveness against Koch’s bacillus. Additionally, some serious side effects must be evaluated before starting any rifabutin-based therapy. Adverse effects include fever, nausea, vomiting and bone marrow suppression. For this reason, full blood count surveillance is required.     

Unusual tumor-like calcification of the mitral annulus: diagnosis and tissue characterization by ultrasound, computed tomography and magnetic resonance imaging.

Calcification of the mitral annulus is a common echocardiographic finding in the elderly, particularly in females. Calcium deposits are generally located in the posterior mitral ring, sometimes extending to the whole mitral annulus and involving the mitral valve apparatus. The present report refers to 2 patients with a very atypical mass-like calcification of the mitral annulus resembling a cardiac tumor. A detailed evaluation of the mass was obtained at transthoracic and transesophageal echocardiography; the differential diagnosis with other intracardiac masses was aided by the use of computed tomography and magnetic resonance imaging. To our knowledge there has been no prior report of such a lesion evaluated at cardiac magnetic resonance imaging.     

Loss of miR‐101 expression promotes Wnt/β‐catenin signalling pathway activation and malignancy in colon cancer cells

Colorectal cancer (CRC) is the second leading cause of cancer‐related mortality in Western countries. Although the aberrant expression of several microRNAs (oncomiRs) is associated with CRC progression, the molecular mechanisms of this phenomenon are still under investigation. Here we show that miR‐101 expression is differentially impaired in CRC specimens, depending on tumour grade. miR‐101 re‐expression suppresses cell growth in 3D, hypoxic survival and invasive potential in CRC cells showing low levels of miR‐101. Additionally, we provide molecular evidence of a bidirectional regulatory mechanism between miR‐101 expression and important CRC pro‐malignant features, such as inflammation, activation of the Wnt/β‐catenin signalling pathway and epithelial–mesenchymal transition (EMT). We then propose that up‐regulated miR‐101 may function as a tumour suppressor in CRC and that its pharmacological restoration might hamper the aggressive behaviour of CRC in vivo. MiR‐101 expression may also represent a cancer biomarker for CRC diagnosis and prognosis. Copyright © 2012 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

Adolescent Exposure to WIN 55212-2 Render the Nigrostriatal Dopaminergic Pathway Activated During Adulthood

BackgroundDuring adolescence, neuronal circuits exhibit plasticity in response to physiological changes and to adapt to environmental events. Nigrostriatal dopaminergic pathways are in constant flux during development. Evidence suggests a relationship between early use of cannabinoids and psychiatric disorders characterized by altered dopaminergic systems, such as schizophrenia and addiction. However, the impact of adolescent exposure to cannabinoids on nigrostriatal dopaminergic pathways in adulthood remains unclear. The aim of this research was to determine the effects of repeated activation of cannabinoid receptors during adolescence on dopaminergic activity of nigrostriatal pathways and the mechanisms underlying this impact during adulthood.MethodsMale Sprague-Dawley rats were treated with 1.2 mg/kg WIN 55212-2 daily from postnatal day 40 to 65. Then no-net flux microdialysis of dopamine in the dorsolateral striatum, electrophysiological recording of dopaminergic neuronal activity, and microdialysis measures of gamma-aminobutyric acid (GABA) and glutamate in substantia nigra par compacta were carried out during adulthood (postnatal days 72–78).ResultsRepeated activation of cannabinoid receptors during adolescence increased the release of dopamine in dorsolateral striatum accompanied by increased population activity of dopamine neurons and decreased extracellular GABA levels in substantia nigra par compacta in adulthood. Furthermore, perfusion of bicuculline, a GABAa antagonist, into the ventral pallidum reversed the increased dopamine neuron population activity in substantia nigra par compacta induced by adolescent cannabinoid exposure.ConclusionsThese results suggest that adolescent exposure to cannabinoid agonists produces disinhibition of nigrostriatal dopamine transmission during adulthood mediated by decreased GABAergic input from the ventral pallidum.     

Intestinal microbial metabolism of phosphatidylcholine: a novel insight in the cardiovascular risk scenario

Intestinal microbiota is a “dynamic organ” influencing host metabolism, nutrition, physiology and immune system. Among its several interactions, the role of a phosphatidylcholine metabolite derived by gut flora activity, i.e., trimethylamine-N-oxide (TMAO), allows perceiving a novel insight in the cardiovascular risk scenario, being a strong predictor of this condition. Based on current reports, including the paper of Tang et al., we describe here: the possible role of intestinal microbiota in cardiovascular risk as well as potential interventions to reduce gut flora TMAO production by diet, probiotics and antibiotics. Finally, we highlight the possibility of evaluating, monitoring and modulating TMAO in order to use its serum levels as a marker of cardiovascular risk in the next future, when the need of controlled studies on large series will be satisfied.