In vitro assessment of the immediate and prolonged antimicrobial action of chlorhexidine gel as an endodontic irrigant against Enterococcus faecalis.

OBJECTIVE: The aim of this study was to assess in vitro the antimicrobial activity of 2% chlorhexidine gel against Enterococcus faecalis , comparing it to other endodontic irrigants (2% chlorhexidine liquid and 5.25% sodium hypochlorite). STUDY DESIGN: Eighty roots of human mandibular premolars were prepared by serial instrumentation technique, autoclaved, and contaminated for 7 days with E faecalis monocultures. The roots were then divided into 5 groups according to the irrigant substance used during the standardized biomechanical preparation. In order to evaluate the antimicrobial action of the irrigant substances, 3 microbial samples were taken: initial (before the biomechanical preparation); post-treatment (immediately after the biomechanical preparation), and final (7 days after the biomechanical preparation). The microbiological samples were plated to count the colony-forming units (CFU). RESULTS: The 2% chlorhexidine gel and 2% chlorhexidine liquid significantly reduced the E faecalis CFU in the post-treatment and final microbiological samples. The 5.25% sodium hypochlorite also reduced the E faecalis CFU immediately after the root canal instrumentation, but it was not able to keep the root canal free of detectable E faecalis in the final sample. CONCLUSIONS: The 2% chlorhexidine gluconate (gel and liquid) antimicrobial ability was more effective than 5.25% sodium hypochlorite in keeping low CFU of E faecalis for 7 days after the biomechanical preparation.     

In vitro evaluation of the antimicrobial activity of calcium hydroxide combined with chlorhexidine gel used as intracanal medicament.

The aim of this study was to investigate the antimicrobial activity of calcium hydroxide (Ca(OH)2) combined with 2% chlorhexidine gluconate (CHX) gel against endodontic pathogens and to compare the results with the ones achieved by Ca(OH)2 mixed with sterile water and by CHX gel alone. Two methods were used: the agar diffusion test and the direct contact test. Ca(OH)2 + 2% CHX gel produced inhibitory zones ranging from 2.84 to 6.5 mm, and required from 30 seconds to 6 hours to eliminate all tested microorganisms. However, 2% CHX gel showed the largest microbial growth zones from 4.33 to 21.67 mm, and required 1 minute or less to inhibit all tested microorganisms. A paste of Ca(OH)2 plus sterile water inhibited only the microorganisms with which it was in direct contact and required from 30 seconds to 24 hours to kill all tested microorganisms. In conclusion, 2% CHX gel + Ca(OH)2 showed better antimicrobial activity than Ca(OH)2 manipulated with sterile water.     

Role of HAMP domains in chemotaxis signaling by bacterial chemoreceptors

Bacterial chemoreceptors undergo conformational changes in response to variations in the concentration of extracellular ligands. These changes in chemoreceptor structure initiate a series of signaling events that ultimately result in regulation of rotation of the flagellar motor. Here we have used cryo-electron tomography combined with 3D averaging to determine the in situ structure of chemoreceptor assemblies in Escherichia coli cells that have been engineered to overproduce the serine chemoreceptor Tsr. We demonstrate that chemoreceptors are organized as trimers of receptor dimers and display two distinct conformations that differ principally in arrangement of the HAMP domains within each trimer. Ligand binding and methylation alter the distribution of chemoreceptors between the two conformations, with serine binding favoring the "expanded" conformation and chemoreceptor methylation favoring the "compact" conformation. The distinct positions of chemoreceptor HAMP domains within the context of a trimeric unit are thus likely to represent important aspects of chemoreceptor structural changes relevant to chemotaxis signaling. Based on these results, we propose that the compact and expanded conformations represent the "kinase-on" and "kinase-off" states of chemoreceptor trimers, respectively.     

Yield of surgery in solid pseudopapillary neoplasms of the pancreas: A case series and literature review

BACKGROUNDSolid pseudopapillary neoplasms (SPN) of the pancreas represents approximately 2% of non-endocrine tumors of the pancreas. It is described in the literature as a rare and predominant tumor in young women. AIMTo report a case series with SPN and analyzing clinical, surgical, anatomopathological characteristics, as well as the prognosis and review of literature. METHODSRetrospective analysis of patients undergoing surgery, with histological diagnosis of SPN between 1998 and 2018, using standardized and prospectively completed forms, performed at the Surgery Service of the Upper Digestive System at Hospital São Rafael/Rede D’Or in Salvador - BA. Review of literature through a database search in MEDLINE/PubMed of retrospective articles. RESULTSFourteen female patients with the average age of 31.6 years (range min-max) were selected. Twelve patients (85.7%) were asymptomatic, being an incidental diagnosis or due to screening for other reasons. One patient had abdominal pain due to gastric compression and another patient had jaundice. The 14 patients were staged with computerized tomography or magnetic resonance imaging. None had evidence of metastasis. In 8 patients (57.1%), the tumor was in the tail and body. The average size was 6.7 cm (range min-18). The type of surgery was according to the anatomical location of the tumor. There was no lymph node involvement. In two cases, vascular resection with the use of a prosthesis was required for reconstruction. The surgical margins were free. In all cases, postoperative immunohistochemistry confirmed that it was a solid pseudo-papillary neoplasia of the pancreas. There has been no disease recurrence in any case so far. CONCLUSIONThe tumors had a benign, indolent and histopathological behavior compatible with the literature. Curative surgery is recommended in all cases.     

Polymerase chain reaction of Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia in primary endodontic infections

The aim of this study was to investigate the correlation between endodontic clinical signs and symptoms and the presence of Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia or their association by nested polymerase chain reaction assay. Microbial samples were taken from 50 cases with necrotic pulp tissues in primary infections. DNA was extracted from the samples, which were analyzed for the presence of three endodontic pathogens by using species-specific primers. P gingivalis, T denticola, and T forsythia were detected in 46%, 38%, and 22% of the symptomatic cases, respectively. The bacterial complex composed by T forsythia, P gingivalis, and T denticola was found in 14% of the cases with spontaneous pain, tenderness to percussion, swelling, and pain on palpation. The high prevalence of P gingivalis, T denticola, and T forsythia in the samples examined suggests that these bacteria are related to the etiology of symptomatic periradicular diseases.     

Increased oxidative stress status in rat serum after five minutes treadmill exercise

Although it is accepted that an important correlation exists between the physical exercise and the oxidative stress status, the data regarding the levels of the main oxidative stress markers after physical training have been difficult to interpret and a subject of many controversies. There are also very few studies regarding the effects of short-time exercise on the oxidative stress status modifications. Thus, in the present report we were interested in studying the modifications of some oxidative stress markers (two antioxidant enzymes-superoxide dismutase and glutathione peroxidase, a lipid peroxidation parameter — malondyaldehide, the total antioxidant status and protein carbonyl levels), from the serum of rats that were subject to one bout of five minutes exercise on a treadmill, when compared to a control sedentary group. In this way, we observed a decrease of superoxide dismutase specific activity in the rats which performed the exercises. Still, no modifications of glutathione peroxidase specific activity were found between groups. In addition, increased levels of malondyaldehide and protein carbonyls were observed in the rats subjected to exercises. In conclusion, our data provides new evidence regarding the increase of the oxidative stress status, as a result of a 5-minutes bout of treadmill exercising in rats, expressed through a decrease in the SOD specific activity and the total antioxidant status and also an increase of the lipid peroxidation and protein oxidation processes.     

Unusual manifestation of the yellow nail syndrome - Case report

The yellow nail syndrome is a rare disorder characterized by the classic triad of yellow and dystrophic nails, lymphedema and pleural effusion. We report in this paper a case of yellow nail syndrome, presenting the classic triad of the disease, associated with an unusual lymph accumulation in the abdomen region.     

Endovascular treatment of unruptured intracranial aneurysms and circulating endothelial cells

Objectives

To evaluate the potential implication of circulating endothelial cells (CECs) in complications following endovascular treatment (EVT) of unruptured intracranial aneurysms. CECs characterized as CD146⁺/CD105⁺/CD45⁻/DAPI⁺ were considered to originate from an altered endothelial cell layer of the vessel wall.

Study design

In 15 patients, CECs were characterized and enumerated by the CellTracks^® System in blood samples from: (1) femoral artery (FA), (2) internal carotid artery (ICA) before (ICA₁) and after procedure (ICA₂), and (3) a peripheral vein before (PV₁) and after EVT (PV₂). Ischemic brain events were assessed using diffusion weighted imaging (DWI-MRI) before and 24 h after EVT.

Results

In ICA₁, the median number of single CECs and clusters of 2–5 CECs were higher than in FA, ICA₂, PV₁ and PV₂ samples (P < 0.001). Clusters >5 cells, sometimes >50 μm, were mainly observed in ICA₁ and never in PV₁, PV₂ or PV samples from ten healthy subjects. This distribution of CECs suggested femoral and ICA injury by the devices used, leading to endothelium shearing and desquamation of CECs. All patients discharged on day two (NIHSS score = 0), however silent ischemic brain lesions were observed in 9/15 (60%).

Conclusions

EVT detaches single and clusters of CECs from wall arteries that may be implicated in silent ischemic brain lesions genesis. Enumeration of CECs associated with DWI-MRI might represent an interesting strategy for monitoring and optimizing endovascular devices, and further limit EVT-related complications.