Publications by authors named "Jorge Vera"

42 Publications

Post-stroke epileptogenesis is associated with altered intrinsic properties of hippocampal pyramidal neurons leading to increased theta resonance.

Neurobiol Dis 2021 Aug 10;156:105425. Epub 2021 Jun 10.

Grass Laboratory, Marine Biological Laboratory, Woods Hole, MA 02543, USA; Carl-Ludwig-Institute for Physiology, Medical Faculty, University of Leipzig, D-04103 Leipzig, Germany. Electronic address:

Brain insults like stroke, trauma or infections often lead to blood-brain barrier-dysfunction (BBBd) frequently resulting into epileptogenesis. Affected patients suffer from seizures and cognitive comorbidities that are potentially linked to altered network oscillations. It has been shown that a hippocampal BBBd in rats leads to in vivo seizures and increased power at theta (3-8 Hz), an important type of network oscillations. However, the underlying cellular mechanisms remain poorly understood. At membrane potentials close to the threshold for action potentials (APs) a subpopulation of CA1 pyramidal cells (PCs) displays intrinsic resonant properties due to an interplay of the muscarine-sensitive K-current (I) and the persistent Na-current (I). Such resonant neurons are more excitable and generate more APs when stimulated at theta frequencies, being strong candidates for contributing to hippocampal theta oscillations during epileptogenesis. We tested this hypothesis by characterizing changes in intrinsic properties of hippocampal PCs one week after post-stroke epileptogenesis, a model associated with BBBd, using slice electrophysiology and computer modeling. We find a higher proportion of resonant neurons in BBBd compared to sham animals (47 vs. 29%), accompanied by an increase in their excitability. In contrast, BBBd non-resonant neurons showed a reduced excitability, presented with lower impedance and more positive AP threshold. We identify an increase in I combined with either a reduction in I or an increase in I as possible mechanisms underlying the observed changes. Our results support the hypothesis that a higher proportion of more excitable resonant neurons in the hippocampus contributes to increased theta oscillations and an increased likelihood of seizures in a model of post-stroke epileptogenesis.
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http://dx.doi.org/10.1016/j.nbd.2021.105425DOI Listing
August 2021

Relationship between internal root resorption and dens in dente.

J Clin Exp Dent 2020 Aug 1;12(8):e800-e804. Epub 2020 Aug 1.

DDS, PhD. University of Tlaxcala, Mexico; Private Practice, Puebla, Mexico.

Background: The aim is to report the treatment and follow-up of three lateral incisors with internal root resorption and dens in dente as a possible cause for their development, managed by root canal treatment and apical obturation with MTA or gutta-percha.

Case Description: This case report presents three clinical cases in which dens invaginatus type 2 is shown as a potential cause for the development of internal root resorption. Two cases were filled with a MTA apical plug technique and one with gutta-percha, and all were follow-up through time.

Practical Implications: The incidence of the association of internal root resorption with dens invaginatus may be underestimated and should be studied. Dens in dente, dens invaginatus, internal root resorption, Mineral Trioxide Aggregate, palatal invagination.
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http://dx.doi.org/10.4317/jced.56944DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7474946PMC
August 2020

Modulation of Frequency Preference in Heterogeneous Populations of Theta-resonant Neurons.

Neuroscience 2020 02 27;426:13-32. Epub 2019 Nov 27.

Department of Biology, Faculty of Sciences, University of Chile. Las Palmeras 3425, Santiago, Chile. Electronic address:

Neurons from several brain regions resonate in the theta frequency range (4-12 Hz), displaying a higher voltage response to oscillatory currents at a preferred 'resonant' frequency (f). Subthreshold resonance could influence spiking and contribute to the selective entrainment of neurons during the network oscillatory activity that accompanies several cognitive processes. Neurons from different regions display resonance in specific theta subranges, suggesting a functional specialization. Further experimental work is needed to characterize this diversity and explore how frequency preference could be dynamically modulated. Theoretical studies have shown that the fine-tuning of resonance depends in a complex way on a variety of intrinsic factors and input properties, but their specific influence is difficult to dissect in cells. We performed slice electrophysiology, dynamic clamping and modelling to assess the differential frequency preference of rat entorhinal stellate neurons, hippocampal CA1 pyramidal neurons and cortical amygdala neurons, which share a hyperpolarization-activated current (I)-dependent resonance mechanism. We found heterogeneous resonance properties among the different types of theta-resonant neurons, as well as in each specific group. In all the neurons studied, f inversely correlated with the effective input resistance (R), a measurable variable that depends on passive and active membrane features. We showed that resonance can be adjusted by manipulations mimicking naturally occurring processes, as the incorporation of a virtual constant conductance or cell depolarization, in a way that preserves the f-R relationship. The modulation of frequency selectivity influences firing by shifting spike frequency and timing, which could influence neuronal communication in an active network.
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http://dx.doi.org/10.1016/j.neuroscience.2019.10.054DOI Listing
February 2020

Multi-objective admission planning problem: a two-stage stochastic approach.

Health Care Manag Sci 2020 Mar 15;23(1):51-65. Epub 2019 Jan 15.

Center for Energy Science and Technology, Skolkovo Institute of Science and Technology, Moscow, Russia.

Effective admission planning can improve inpatient throughput and waiting times, resulting in better quality of service. The uncertainty in the patient arrival and the availability of resources makes the patient's allocation difficult to manage. Thus, in the admission process hospitals aim to accomplish targets of resource utilization and to lower the cost of service. Both objectives are related and in conflict. In this paper, we present a bi-objective stochastic optimization model to study the trade-off between the resource utilization and the cost of service, taking into account demand and capacity uncertainties. Real data from the surgery and medical areas of a Chilean public hospital are used to illustrate the approach. The results show that the solutions of our approach outperform the actual practice in the Chilean hospital.
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http://dx.doi.org/10.1007/s10729-018-9464-4DOI Listing
March 2020

Rote und juckende bilaterale supraorbitale Schwellungen.

J Dtsch Dermatol Ges 2018 Dec;16(12):1503-1506

Klinik für Dermatologie, Venerologie und Allergologie, Charité - Universitätsmedizin Berlin, Deutschland.

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http://dx.doi.org/10.1111/ddg.13687_gDOI Listing
December 2018

Red and itchy bilateral supraorbital swellings.

J Dtsch Dermatol Ges 2018 Dec 9;16(12):1503-1506. Epub 2018 Nov 9.

Department of Dermatology and Allergy, Charité - Universitätsmedizin Berlin, Germany.

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http://dx.doi.org/10.1111/ddg.13687DOI Listing
December 2018

[Validation of a scale of health beliefs about type 1 diabetes for the Mexican context: HBM-T1DM].

Salud Publica Mex 2018 Mar-Apr;60(2):175-183

EGADE Business School, Tecnológico de Monterrey. Ciudad de México, México.

Objective: To generate a scale to measure health beliefs among Mexican adolescents and young people with type 1 diabetes (T1DM) to determine the extent to which they affect adherence to treatment and to be able to develop more effective social marketing campaigns.

Material And Methods: Based on the Health Belief Model (HBM), a scale was generated; three field tests were applied, and it was administered in two regions of Mexico to young people with type 1 diabetes.Tests of reliability, stability, convergence-discrimination and predictive validity were developed.

Results: The main predictor is perceived barriers to treatment adherence, followed by self-efficacy to disease control, susceptibility/vulnerability to disease complications and perceived benefits of treatment.

Conclusions: This scale may be especially useful for better monitoring young Mexican patients with T1DM and prevent sequelae of disease.
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http://dx.doi.org/10.21149/8838DOI Listing
January 2019

Autotransplantation of a Premolar with Incipient Root Development, an 18-Year Follow-Up.

Eur Endod J 2017 2;2(1):1-5. Epub 2017 Nov 2.

Department of Endodontics, New York University, New York, USA.

In young patients, premature tooth loss in the anterior maxilla after trauma is challenging for the patient and the dental professional, with serious implications from aesthetic and functional points of view, as well as from a craniofacial growth aspect perspective. Premolars autotransplanted into the maxillary anterior region have been shown to be a biological alternative in this situation. This report describes the clinical management of a case of premature loss of a maxillary central incisor after traumatic injury. A mandibular premolar at the stage of initial root development was transplanted into the alveolar socket of the lost incisor. After 18 years, the transplanted tooth remained responsive to pulp sensibility tests and the periradicular bone and soft tissues were within normal limits. Autotransplantation of premolar teeth into the maxilla could be considered an excellent treatment choice with many biological advantages over implants or fixed dentures as long as proper case selection is followed.
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http://dx.doi.org/10.14744/eej.2017.170080DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7757955PMC
November 2017

Intracanal Cryotherapy Reduces Postoperative Pain in Teeth with Symptomatic Apical Periodontitis: A Randomized Multicenter Clinical Trial.

J Endod 2018 Jan 1;44(1):4-8. Epub 2017 Nov 1.

Department of Conservative Dentistry, School of Dentistry, Complutense University, Madrid, Spain.

Introduction: A prospective, multicentered, randomized clinical trial was designed to assess if controlled irrigation with cold saline could result in less incidence and intensity of postoperative pain in patients presenting with pulp necrosis and symptomatic apical periodontitis.

Methods: A total of 210 patients (presenting with necrotic uniradicular teeth with a diagnosis of symptomatic apical periodontitis and a preoperative visual analog scale (VAS) score higher than 7) were randomly allocated in the control or experimental group after the completion of shaping and cleaning procedures. The experimental group received a final irrigation with 20 mL sterile cold (2.5°C) saline solution delivered to the working length with a sterile, cold (2.5°C) Endovac microcannula (Kerr Endo, Orange Country, CA) for 5 minutes. The same protocol was used in the control group with room temperature saline solution. Patients were instructed to record the presence, duration and level of postoperative pain, and analgesic medication intake. A logistic regression was used to compare the incidence of postoperative pain and the need for painkillers between groups. Differences in general pain intensity between groups were analyzed using the ordinal (linear) chi-square test. Postoperative pain after 6, 24, and 72 hours (recorded in a VAS scale) and the need for analgesic medication intake between the 2 groups were assessed using the Mann-Whitney U test.

Results: Patients in the control group presented a significantly higher incidence of postoperative pain, intensity, and need for medication intake (P < .05).

Conclusions: Cryotherapy reduced the incidence of postoperative pain and the need for medication intake in patients presenting with a diagnosis of necrotic pulp and symptomatic apical periodontitis.
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http://dx.doi.org/10.1016/j.joen.2017.08.038DOI Listing
January 2018

Biofilms in Endodontics-Current Status and Future Directions.

Int J Mol Sci 2017 Aug 11;18(8). Epub 2017 Aug 11.

Discipline of Endodontology, Faculty of Dentistry, The University of Hong Kong, Pok Fu Lam, Hong Kong, China.

Microbiota are found in highly organized and complex entities, known as biofilms, the characteristics of which are fundamentally different from microbes in planktonic suspensions. Root canal infections are biofilm mediated. The complexity and variability of the root canal system, together with the multi-species nature of biofilms, make disinfection of this system extremely challenging. Microbial persistence appears to be the most important factor for failure of root canal treatment and this could further have an impact on pain and quality of life. Biofilm removal is accomplished by a chemo-mechanical process, using specific instruments and disinfecting chemicals in the form of irrigants and/or intracanal medicaments. Endodontic research has focused on the characterization of root canal biofilms and the clinical methods to disrupt the biofilms in addition to achieving microbial killing. In this narrative review, we discuss the role of microbial biofilms in endodontics and review the literature on the role of root canal disinfectants and disinfectant-activating methods on biofilm removal.
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http://dx.doi.org/10.3390/ijms18081748DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5578138PMC
August 2017

Ensa controls S-phase length by modulating Treslin levels.

Nat Commun 2017 08 8;8(1):206. Epub 2017 Aug 8.

Université de Montpellier, Centre de Recherche de Biologie Cellulaire de Montpellier, Equipe Labellisée 'Ligue Contre le Cancer', CNRS UMR 5237, 1919 Route de Mende, 34293, Montpellier cedex 5, France.

The Greatwall/Ensa/PP2A-B55 pathway is essential for controlling mitotic substrate phosphorylation and mitotic entry. Here, we investigate the effect of the knockdown of the Gwl substrate, Ensa, in human cells. Unexpectedly, Ensa knockdown promotes a dramatic extension of S phase associated with a lowered density of replication forks. Notably, Ensa depletion results in a decrease of Treslin levels, a pivotal protein for the firing of replication origins. Accordingly, the extended S phase in Ensa-depleted cells is completely rescued by the overexpression of Treslin. Our data herein reveal a new mechanism by which normal cells regulate S-phase duration by controlling the ubiquitin-proteasome degradation of Treslin in a Gwl/Ensa-dependent pathway.The Greatwall/Ensa/PP2A-B55 pathway controls mitotic substrate phosphorylation and mitotic entry. Here the authors show that cells regulate S phase duration by controlling the ubiquitin-proteasome degradation of Treslin in a Gwl/Ensa-dependent pathway.
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http://dx.doi.org/10.1038/s41467-017-00339-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5547116PMC
August 2017

Competition between Persistent Na and Muscarine-Sensitive K Currents Shapes Perithreshold Resonance and Spike Tuning in CA1 Pyramidal Neurons.

Front Cell Neurosci 2017 8;11:61. Epub 2017 Mar 8.

Department of Biology, Cell Physiology Center, University of Chile Santiago, Chile.

Neurons from many brain regions display intrinsic subthreshold theta-resonance, responding preferentially to theta-frequency oscillatory stimuli. Resonance may contribute to selective communication among neurons and to orchestrate brain rhythms. CA1 pyramidal neurons receive theta activity, generating place fields. In these neurons the expression of perithreshold frequency preference is controversial, particularly in the spiking regime, with evidence favoring either non-resonant (integrator-like) or resonant behavior. Perithreshold dynamics depends on the persistent Na current developing above -70 mV and the muscarine-sensitive K current activating above -60 mV. We conducted current and voltage clamp experiments in slices to investigate perithreshold excitability of CA1 neurons under oscillatory stimulation. Around 20% of neurons displayed perithreshold resonance that is expressed in spiking. The remaining neurons (~80%) acted as low-pass filters lacking frequency preference. Paired voltage clamp measurement of and showed that perithreshold activation of is in general low while is high enough to depolarize neurons toward threshold before resonance expression, explaining the most abundant non-resonant perithreshold behavior. Partial blockade of by pharmacological tools or dynamic clamp changed non-resonant to resonant behavior. Furthermore, shifting activation toward hyperpolarized potentials by dynamic clamp also transformed non-resonant neurons into resonant ones. We propose that the relative levels of and control perithreshold behavior of CA1 neurons constituting a gating mechanism for theta resonance in the spiking regime. Both currents are regulated by intracellular signaling and neuromodulators which may allow dynamic switching of perithreshold behavior between resonant and non-resonant.
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http://dx.doi.org/10.3389/fncel.2017.00061DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5340745PMC
March 2017

A Cellular Mechanism for Main and Accessory Olfactory Integration at the Medial Amygdala.

J Neurosci 2016 Feb;36(7):2083-5

Departamento de Biología, Universidad de Chile, Santiago, Chile, 7800003

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http://dx.doi.org/10.1523/JNEUROSCI.4304-15.2016DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6602037PMC
February 2016

Preoperative hydration with 0.9% normal saline to prevent acute kidney injury after major elective open abdominal surgery: A randomised controlled trial.

Eur J Anaesthesiol 2016 06;33(6):436-43

From the Department of Anaesthesiology (ABS, AMC-T, JV); Department of Biostatistics, "CIBER Epidemiology and Public Health" (JZ, AM); Department of Biochemistry (JMdR); and Department of Nephrology, Ramón y Cajal University Hospital, Madrid, Spain (FL).

Background: Postoperative acute kidney injury (AKI) is the second leading cause of hospital-acquired AKI. Although many preventive strategies have been tested, none of them has been totally effective.

Objective: We investigated whether preoperative intravenous hydration with 0.9% normal saline could prevent postoperative AKI.

Design: Randomised controlled trial.

Setting: University Ramón y Cajal Hospital, Spain, from June 2006 to February 2011.

Patients: Total 328 inpatients scheduled for major elective open abdominal surgery.

Intervention: 0.9% normal saline at a dose of 1.5 ml kg h for 12 h before surgery.

Main Outcome Measures: The primary outcome was the overall postoperative AKI incidence during the first week after surgery defined by risk, injury, failure, loss, end-stage kidney disease (RIFLE) and AKI network (AKIN) creatinine criteria. Secondary endpoints were the need for ICU admission, renal replacement therapy during the study period and adverse events and hospital mortality during hospital admission.

Results: There was no difference in the incidence of AKI between groups: 4.7% in the normal saline group versus 5.0% in the control group and 11.4% in the 0.9% normal saline group versus 7.9% in the control group as assessed by the RIFLE and AKIN creatinine criteria, respectively. Absolute risk reductions (95% confidence interval) were -0.3% (-5.3 to 4.7%) for RIFLE and 3.5% (-10.2 to 3.6%) for AKIN. ICU admission after surgery was required in 44.5% of all participants. Only 2 (0.7%) patients required renal replacement therapy during the first week after surgery. The analysis of adverse events did not show statistically significant differences between the groups except for pain. In our population, 8 (2.4%) patients died during their hospital admission.

Conclusion: Intravenous hydration with 0.9% normal saline before major open abdominal surgery was not effective in preventing postoperative AKI. No safety concerns were identified during the trial.

Trial Registrations: Clinical trials.gov: NCT00953940 and EUDRA CT: 2005-004755-35.
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http://dx.doi.org/10.1097/EJA.0000000000000421DOI Listing
June 2016

Compliance with management guidelines in patients with suspected dengue.

Bol Asoc Med P R 2016 ;108(1):53-56

Dengue is an endemic disease in Puerto Rico, with three to nine thousand suspected dengue cases reported yearly. In PR, physicians are required to maintain medical education courses about dengue in order to recertify their medical licenses. The purpose of this study was to describe characteristics of patients admitted to Bella Vista Hospital with suspected dengue and estimate the compliance with guidelines established by the CDC documented in medical records. A total of 197 medical records of patients admitted with diagnosis of suspected dengue during January 1, 2013 through December 31, 2013 were reviewed. The annual distribution of admitted cases showed a higher incidence during the months of June through September, with August having the higher incidence of all. Combined aches and pains were most commonly reported at admission with a prevalence of 82%. In general there was a low prevalence of severe disease as per definition at presentation (DM, clinical fluid accumulation, hepatomegaly, pregnancy and/or renal insufficiency). Overall, compliance with CDC established guidelines were only partially followed. The guideline that was followed more frequently was a daily CBC, with 95% of patients having this as part of their management. Prevalence of administration of isotonic intravenous fluids was 63%, monitoring of vital signs was 48%), and administration of bolus of intravenous fluid was11%. No fatalities were reported during the period.
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December 2017

Bacterial Species, Susceptibility to antibiotics and characteristics of patients with surgical site infections.

Bol Asoc Med P R 2016 ;108(1):19-22

Surgical site infections (SSI) are the most common healthcare-associated infections. Approximately 2-5% of all surgeries develop SSI as a complication. These infections are responsible for significant fatality, morbidity, and length of hospital stay. The purpose of this study was to describe characteristics of SSI in a community hospital in Puerto Rico. This was cross-sectional study. Between July 2013 and August 2015, 5468 major operative procedures were performed and 31 SSI were reported for an overall SSI incidence rate of 0.57%. A total of 31 cases of SSI were studied. The mean age of patients was 59.4 years, with a range of to 29 to 89 years. The median age was 64 years. The sex distribution showed 22 women (71%) and 9 men (29%). The prevalence rate of diabetes mellitus was 13/31 (42%). In this study 90% of patients with SSI had at least one underlying health condition (diabetes, hypertension, obesity, age > 65 years). Location of surgical site infections were: abdominal 16 (52%), orthopedic 4 (13%), pelvic 7 (22%), stump 3 (10%), and chest tube 1 (3%). A total of 12 different bacterial pathogens were found. A single etiologic agent was identified in 18 patients (53%) and multiple agents were found in 13 patients (47%). Enterococcus faecalis was the most common pathogen (45% of patients) followed by Escherichia coli (39% of patients). The majority of bacteria isolated from cultures were susceptible to B-lactams and aminoglycosides.
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December 2017

Greatwall promotes cell transformation by hyperactivating AKT in human malignancies.

Elife 2015 Nov 27;4. Epub 2015 Nov 27.

Centre de Recherche de Biochimie Macromoléculaire, Université de Montpellier, Montpellier, France.

The PP2A phosphatase is often inactivated in cancer and is considered as a tumour suppressor. A new pathway controlling PP2A activity in mitosis has been recently described. This pathway includes the Greatwall (GWL) kinase and its substrates endosulfines. At mitotic entry, GWL is activated and phosphorylates endosulfines that then bind and inhibit PP2A. We analysed whether GWL overexpression could participate in cancer development. We show that GWL overexpression promotes cell transformation and increases invasive capacities of cells through hyperphosphorylation of the oncogenic kinase AKT. Interestingly, AKT hyperphosphorylation induced by GWL is independent of endosulfines. Rather, GWL induces GSK3 kinase dephosphorylation in its inhibitory sites and subsequent SCF-dependent degradation of the PHLPP phosphatase responsible for AKT dephosphorylation. In line with its oncogenic activity, we find that GWL is often overexpressed in human colorectal tumoral tissues. Thus, GWL is a human oncoprotein that promotes the hyperactivation of AKT via the degradation of its phosphatase, PHLPP, in human malignancies.
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http://dx.doi.org/10.7554/eLife.10115DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4733044PMC
November 2015

Effect of Intracanal Cryotherapy on Reducing Root Surface Temperature.

J Endod 2015 Nov 1;41(11):1884-7. Epub 2015 Oct 1.

Department of Endodontics, University of North Carolina School of Dentistry, Chapel Hill, North Carolina; Lebanese University Dental School, Beirut, Lebanon.

Introduction: The positive effect of cryotherapy has been widely described in medicine. The aim of the present study was to validate a new methodology to reduce and maintain external root surface temperature for at least 4 minutes.

Methods: Twenty extracted single-rooted teeth were instrumented to size 35/.06 and subjected to 2 different irrigation interventions with a repeated-measures design using 5% sodium hypochlorite first (control) and 2.5°C cold saline solution later (experimental). In both, 20 mL of the irrigant solution was delivered for a total time of 5 minutes with a microcannula attached to the EndoVac system (Kerr Endo, Orange County, CA) inserted to the working length. The initial and lowest temperatures were recorded in the apical 4 mm with a digital thermometer for both irrigants. Data were analyzed with the repeated measure analysis of variance (Greenhouse-Geisser correction) and Bonferroni post hoc tests. Differences in maintaining a -10°C temperature reduction over 4 minutes were assessed with the Fisher exact test.

Results: Although significant differences were found between the initial and lowest temperatures in both the control and experimental irrigation procedures (P < .001), the experimental intervention reduced it almost 10 times that of the control. When maintaining a -10°C temperature reduction over 4 minutes, the teeth in the experimental group also sustained significantly better results (P = 3.047 × 10(-10)).

Conclusions: Using cold saline solution as the final irrigant reduced the external root surface temperature more than 10°C and maintained it for 4 minutes, which may be enough to produce a local anti-inflammatory effect in the periradicular tissues.
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http://dx.doi.org/10.1016/j.joen.2015.08.009DOI Listing
November 2015

Clinical and radiological indicators of severity in patients with acute pancreatitis.

Bol Asoc Med P R 2015 Jan-Mar;107(1):33-7

Unlabelled: The purpose of this study was to estimate the degree of association between clinical (Ranson criteria) and radiological variables (Abdominal CT scan) with degree of severity in patients with a diagnosis of acute pancreatitis.

Method: All patients discharged with the diagnosis of acute pancreatitis from January 1, 2010 through December 31, 2012 in a community hospital were selected (N=174). The following variables were studied: sex; age; weight; height; admission and discharge dates; presence of several chronic conditions; laboratory results included in Ranson criteria; abdominal CT category; outcome, including fatality surgery, and other complications. Analysis included descriptive statistics and Risk-Ratios for complications for different groups of subjects, using clinical and radiological criteria.

Results: The incidence rate of complications, including fatality, surgery and organ failure was 36.2%. Factors that showed significant associations with the risk of complication on crude analysis were gallbladder disease with a RR=1.78 ($95% CI: 1.22, 2.60) and abnormal abdominal CT with a RR=1.85 (95% CI: 1.11, 3.07). with multivariate analysis, gallbladder disease, abnormal abdominal CT, and presence of 3 or more Ranson's criteria showed increased risk for complications, but the results did not reach statistical significance.

Discussion: The factors that seemed to be associated with increased rate of complications in subjects with acute pancreatitis were gallbladder disease, abnormal abdominal CT, and 3 or more Ranson's criteria. The Results did not show statistical significance probably because of low statistical power of the study.
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June 2015

3D mapping of the irrigated areas of the root canal space using micro-computed tomography.

Clin Oral Investig 2015 May 4;19(4):859-66. Epub 2014 Sep 4.

Department of Endodontics, Dental School of Ribeirão Preto, University of São Paulo, Av. Do Café s/n, Bairro Monte Alegre, Ribeirão, Preto-SP, CEP 14.040-904, Brazil,

Objectives: The aim of this study was to introduce a methodology to map irrigant spreadability within the root canal space using micro-computed tomography (micro-CT).

Materials And Methods: Mandibular molars presenting Vertucci's types I and II canal configurations were selected, and four scans using isotropic resolution of 19.5 μm were accomplished per tooth: prior to treatment (S1), after glide path (S2) and after root canal preparation (S3 and S4). A contrast solution (CS) was used to irrigate the canals at stages S2 and S4. The touched and untouched surface areas of the canals, the volume of irrigant-free areas and the percentage volume occupied by the CS were calculated. Density, surface tension and the spread pattern of the CS and 2.5% NaOCl were also evaluated.

Results: In the type I mesial root, there was an increase in the percentage volume of free-irrigated areas from S2 to S4 preparation steps, whilst in the distal roots and type II mesial root, a decrease of irrigant-free areas was observed. The use of CS allowed the quantification of the touched surface area and the volume of the root canal occupied by the irrigating solution. Density (g/mL) and surface tension (mN/m) of the CS and 2.5% NaOCl were 1.39 and 47.5, and 1.03 and 56.2, respectively. Besides, a similar spread pattern of the CS and 2.5% NaOCl in a simulated root canal environment was observed.

Conclusions: This study introduced a new methodology for mapping the irrigating solution in the different stages of the root canal preparation and proved useful for in situ volumetric quantification and qualitative evaluation of irrigation spreading and irrigant-free areas.

Clinical Relevance: Micro-computed tomographic technology may provide a comprehensive knowledge of the flush effectiveness by different irrigants and delivery systems in order to predict the optimal cleaning and disinfection conditions of the root canal space.
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http://dx.doi.org/10.1007/s00784-014-1311-5DOI Listing
May 2015

Debris remaining in the apical third of root canals after chemomechanical preparation by using sodium hypochlorite and glyde: an in vivo study.

J Endod 2014 Sep 9;40(9):1419-23. Epub 2014 Jul 9.

Endodontic Postgraduate Program, Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara, Guadalajara, México.

Introduction: During chemomechanical instrumentation, several liquid or paste substances are used to ease the action of the files and to eliminate debris and the smear layer. The aim of this study was to evaluate whether the use of a paste containing EDTA during cleaning and shaping of the root canal helps to eliminate debris.

Methods: Twenty root canals in dog teeth were instrumented by a crown-down technique by using nickel-titanium rotary files. In 10 root canals (group A), sodium hypochlorite was used during instrumentation, followed by a final irrigation with 17% liquid EDTA. In another 10 canals (group B), sodium hypochlorite was again used as the irrigating solution, but Glyde File Prep paste was used with every instrument, and a final irrigation with EDTA was also carried out. Two additional teeth were used as positive and 2 as negative controls. The jaws were prepared for histologic evaluation.

Results: In group A where Glyde was not used during cleaning and shaping, little or no debris was found in the apical third of the instrumented root canals; however; in group B in which Glyde File Prep paste was used during chemomechanical instrumentation, moderate to high accumulation of debris was observed in the apical third.

Conclusions: The use of Glyde File Prep paste during rotary mechanical instrumentation favors the accumulation of debris in the apical third of the root canals. Irrigation with NaOCl and a final flush with EDTA by means of a small-gauge needle with simultaneous aspiration led to less accumulation of debris than in the Glyde File Prep group (P < .05).
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http://dx.doi.org/10.1016/j.joen.2014.05.013DOI Listing
September 2014

S-Shaped Canals: A Series of Cases Performed by Four Specialists around the World.

Case Rep Dent 2014 16;2014:359438. Epub 2014 Jul 16.

Grande Rio University, Rio de Janeiro, Brazil.

Recognition of anatomical variations is a real challenge for clinicians undertaking therapy regardless of the teeth that are to be treated. The extent of the curvature is one of the most important variables that could lead to instrument fracture. In clinical conditions, two curves can be present in the same root canal trajectory. This type of geometry is denoted as the "S" shape, and it is a challenging condition. This report describes a different clinical and educational scenario where four specialists around the world present different approaches for the treatment of root canals with double curvatures or S-shaped canals. Endodontic therapy is a very nuanced and challenging science and art. The clinical and teaching experience of the authors show different approaches that can be successfully employed to treat challenging teeth having roots with multiple curves. The necessity of precise knowledge of the root canal morphology and its variation is also underlined.
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http://dx.doi.org/10.1155/2014/359438DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4124786PMC
August 2014

Transient apical breakdown and its relationship with orthodontic forces: a case report.

J Endod 2014 Aug 28;40(8):1265-7. Epub 2014 Feb 28.

Endodontic Postgraduate Program, Universidad Autónoma of Queretaro, Querétaro de Arteaga, Mexico. Electronic address:

Introduction: Transient apical breakdown (TAB) caused by orthodontic treatment is a reversible resorptive process in which the apex of a tooth shows some radiographic evidence of resorption and the crown may display some discoloration. It usually requires no treatment other than monitoring and elimination of the orthodontic forces applied to the tooth.

Methods: This report describes the case of a 48-year-old man patient who was referred to the department of endodontics for evaluation of some discoloration of his upper right central incisor, which was undergoing orthodontic treatment. The tooth was nonresponsive to sensitivity tests, it was sensitive to percussion, and, radiographically, there was some evidence of root resorption and apical radiolucency.

Results: Because TAB was the suspected cause of the signs and symptoms, no treatment was performed on the tooth except for periodic recalls, and lightening and eventual removal of the orthodontic appliances was indicated.

Conclusions: Ten weeks after the initial appointment and removal of the applied orthodontic forces, color improvement was observed, accompanied by a return of tooth sensitivity to cold tests.
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http://dx.doi.org/10.1016/j.joen.2014.01.006DOI Listing
August 2014

Electrical resonance in the θ frequency range in olfactory amygdala neurons.

PLoS One 2014 21;9(1):e85826. Epub 2014 Jan 21.

Department of Biology, Faculty of Sciences, University of Chile, Santiago, Chile.

The cortical amygdala receives direct olfactory inputs and is thought to participate in processing and learning of biologically relevant olfactory cues. As for other brain structures implicated in learning, the principal neurons of the anterior cortical nucleus (ACo) exhibit intrinsic subthreshold membrane potential oscillations in the θ-frequency range. Here we show that nearly 50% of ACo layer II neurons also display electrical resonance, consisting of selective responsiveness to stimuli of a preferential frequency (2-6 Hz). Their impedance profile resembles an electrical band-pass filter with a peak at the preferred frequency, in contrast to the low-pass filter properties of other neurons. Most ACo resonant neurons displayed frequency preference along the whole subthreshold voltage range. We used pharmacological tools to identify the voltage-dependent conductances implicated in resonance. A hyperpolarization-activated cationic current depending on HCN channels underlies resonance at resting and hyperpolarized potentials; notably, this current also participates in resonance at depolarized subthreshold voltages. KV7/KCNQ K+ channels also contribute to resonant behavior at depolarized potentials, but not in all resonant cells. Moreover, resonance was strongly attenuated after blockade of voltage-dependent persistent Na+ channels, suggesting an amplifying role. Remarkably, resonant neurons presented a higher firing probability for stimuli of the preferred frequency. To fully understand the mechanisms underlying resonance in these neurons, we developed a comprehensive conductance-based model including the aforementioned and leak conductances, as well as Hodgkin and Huxley-type channels. The model reproduces the resonant impedance profile and our pharmacological results, allowing a quantitative evaluation of the contribution of each conductance to resonance. It also replicates selective spiking at the resonant frequency and allows a prediction of the temperature-dependent shift in resonance frequency. Our results provide a complete characterization of the resonant behavior of olfactory amygdala neurons and shed light on a putative mechanism for network activity coordination in the intact brain.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0085826PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3897534PMC
October 2014

Ca2+-activated Cl- channels of the ClCa family express in the cilia of a subset of rat olfactory sensory neurons.

PLoS One 2013 9;8(7):e69295. Epub 2013 Jul 9.

Department of Biology, Faculty of Sciences, University of Chile, Las Palmeras, Santiago, Chile.

The Ca(2+)-activated Cl(-) channel is considered a key constituent of odor transduction. Odorant binding to a specific receptor in the cilia of olfactory sensory neurons (OSNs) triggers a cAMP cascade that mediates the opening of a cationic cyclic nucleotide-gated channel (CNG), allowing Ca(2+) influx. Ca(2+) ions activate Cl(-) channels, generating a significant Cl(-) efflux, with a large contribution to the receptor potential. The Anoctamin 2 channel (ANO2) is a major constituent of the Cl(-) conductance, but its knock-out has no impairment of behavior and only slightly reduces field potential odorant responses of the olfactory epithelium. Likely, an additional Ca(2+)-activated Cl(-) channel of unknown molecular identity is also involved. In addition to ANO2, we detected two members of the ClCa family of Ca(2+)-activated Cl(-) channels in the rat olfactory epithelium, ClCa4l and ClCa2. These channels, also expressed in the central nervous system, may correspond to odorant transduction channels. Whole Sprague Dawley olfactory epithelium nested RT-PCR and single OSNs established that the mRNAs of both channels are expressed in OSNs. Real time RT-PCR and full length sequencing of amplified ClCa expressed in rat olfactory epithelium indicated that ClCa4l is the most abundant. Immunoblotting with an antibody recognizing both channels revealed immunoreactivity in the ciliary membrane. Immunochemistry of olfactory epithelium and OSNs confirmed their ciliary presence in a subset of olfactory sensory neurons. The evidence suggests that ClCa4l and ClCa2 might play a role in odorant transduction in rat olfactory cilia.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0069295PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3706372PMC
February 2014

Effect of maintaining apical patency on irrigant penetration into the apical two millimeters of large root canals: an in vivo study.

J Endod 2012 Oct 28;38(10):1340-3. Epub 2012 Jul 28.

University of Tlaxcala, Tlaxcala, Mexico.

Introduction: Factors such as complex root canal anatomy and the vapor lock phenomenon have been shown to limit the penetration of irrigating solutions into the apical third in both in vivo and in vitro studies involving small and wide canals. Hence, the aim of this study was to determine whether the use of a patency file is related to the presence of a radiopaque irrigating solution in the apical 2 mm of large human root canals.

Methods: Forty-three large human root canals were randomly divided into 2 groups. Apical patency was maintained in 1 group (P, n = 22) during shaping and cleaning procedures with a no. 10 K-file 1 mm beyond the working length (WL) but not in the other group (no patency [NP], n = 21). In both groups, the canals were shaped with the K3 system. Irrigation was performed with 1 mL of a solution prepared with a radiopaque contrast medium and 5.25% sodium hypochlorite. Digital images were taken, and 2 calibrated readers determined the presence or absence of the irrigating solution in the apical 2 mm of the root canals.

Results: There were significantly more canals with irrigant in the apical 2 mm when apical patency was maintained with a no. 10- Kfile 1 mm beyond the WL than when apical patency was not maintained throughout the cleaning and shaping procedures (P = .04).

Conclusions: Maintaining apical patency improves the delivery of irrigants into the apical third of large human root canals.
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http://dx.doi.org/10.1016/j.joen.2012.06.005DOI Listing
October 2012

Autotransplantation of a premolar: a long-term follow-up report of a clinical case.

J Endod 2012 Aug 16;38(8):1149-52. Epub 2012 May 16.

Department of Oral Health, Universidad Autónoma Manizales, Manizales, Colombia.

Introduction: This report describes the clinical management of a case in which a maxillary central incisor was lost after a traumatic injury.

Methods: A mandibular premolar with incomplete root development was transplanted into the alveolar socket of the lost central incisor.

Results: The case evolved favorably for 12 years, remaining vital to pulp sensitivity tests and developing a favorable crown-root ratio even after it was orthodontically moved.

Conclusions: Premolar autotransplantation should be considered an important and valid biological alternative in cases of premature tooth loss both in young patients and adults in order to avoid or delay implant placement or other type of restoration.
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http://dx.doi.org/10.1016/j.joen.2012.04.001DOI Listing
August 2012

One- versus two-visit endodontic treatment of teeth with apical periodontitis: a histobacteriologic study.

J Endod 2012 Aug 12;38(8):1040-52. Epub 2012 Jun 12.

Department of Endodontics, University of Tlaxcala, Tlaxcala, Mexico.

Introduction: This study analyzed the in vivo microbiological status of the root canal systems of mesial roots of mandibular molars with primary apical periodontitis after 1- or 2-visit endodontic treatment.

Methods: Mesial root canals were instrumented by using either a combination of K3 and LightSpeed instruments (mesiobuccal canals) or the ProTaper system (mesiolingual canals), with 5% NaOCl irrigation. Patency files were used. Smear layer was removed, and a final rinse with 5 mL of 2% chlorhexidine was performed. In the 2-visit group (7 roots, 14 canals), canals were medicated with calcium hydroxide for 1 week and then obturated by using the continuous wave of compaction technique. In the 1-visit group (6 roots, 12 canals), canals were immediately obturated after chemomechanical procedures. Teeth were extracted 1 week after root canal instrumentation and processed for histobacteriologic analysis.

Results: In the 1-visit group, no case was completely free of bacteria; residual bacteria occurred in the main root canal (5 of 6 cases), isthmus (5 of 6), apical ramifications (4 of 6), and dentinal tubules (5 of 6). In the 2-visit group, 2 cases were rendered bacteria-free; residual bacteria were found in the main canal only in 2 cases (none of them with persistent dentinal tubule infection), in the isthmus (4 of 7 cases), and in ramifications (2 of 7). The 2 instrumentation techniques performed similarly. When filling material was observed in ramifications, it was usually intermixed with necrotic tissue, debris, and bacteria.

Conclusions: The 2-visit protocol by using an interappointment medication with calcium hydroxide resulted in improved microbiological status of the root canal system when compared with the 1-visit protocol. Residual bacteria were more frequent and abundant in ramifications, isthmuses, and dentinal tubules when root canals were treated without an interappointment medication. Apical ramifications and isthmuses were never completely filled. The use of an antibacterial interappointment agent is necessary to maximize bacterial reduction before filling.
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http://dx.doi.org/10.1016/j.joen.2012.04.010DOI Listing
August 2012

Comparison of in vivo and in vitro readings when testing the accuracy of the Root ZX apex locator.

J Endod 2012 Feb 5;38(2):236-9. Epub 2011 Dec 5.

Department of Endodontics, Universitat Internacional de Catalunya, Barcelona, Spain.

Introduction: The purpose of the study was to compare the accuracy of the Root ZX electronic apex locator (J Morita Corp, Tokyo, Japan) between an in vivo and an in vitro model.

Methods: The working length (WL) was determined electronically for 46 root canals of human teeth with a 15 K-file using both in vitro (n = 23) and in vivo (n = 23) models. The files were fixed at the WL. The apical 4 mm of each canal was trimmed to expose the file tip. The samples were observed under a scanning electron microscope, and the distance from the file tip to the point 0.5 mm coronal to the major foramen (the final WL) was measured. The data were analyzed using the Student t test, and significance was set at P ≤ .05.

Results: The statistical analysis revealed no significant differences between the in vivo group and in vitro group with respect to the accuracy of the Root ZX device in determining the final WL. The mean distance from the final WL to the file tip was 0.23 ± 0.39 mm for the in vivo group and 0.29 ± 0.32 mm for the in vitro group. In determining the final WL, the Root ZX was accurate 78.3% of the time to ±0.5 mm and 100% of the time to ±1 mm in the in vivo group, whereas it was accurate 74% of the time to ±0.5 mm and 100% of the time to ±1 mm in the in vitro group.

Conclusions: No statistically significant differences were observed between the in vivo group and the in vitro group.
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http://dx.doi.org/10.1016/j.joen.2011.10.008DOI Listing
February 2012

Dynamic movement of intracanal gas bubbles during cleaning and shaping procedures: the effect of maintaining apical patency on their presence in the middle and cervical thirds of human root canals-an in vivo study.

J Endod 2012 Feb 6;38(2):200-3. Epub 2011 Dec 6.

University of Tlaxcala, Tlaxcala, Mexico.

Introduction: The vapor lock effect has been shown to limit the penetration of irrigating solutions into the apical third of root canals both in vivo and in vitro; however, little attention has been given to gas bubbles in the remainder of the root canal system.

Methods: Seventy-one human root canals were randomly divided into 4 groups. Apical patency was maintained in 2 groups in both small (PS) (n = 21) and big canals (PB) (n = 15) during shaping and cleaning procedures with a 10 K-file 1 mm beyond working length but not in the other 2 groups: no patency, small canals (NPS) (n = 19) and no patency, big canals (NPB) (n = 16). Irrigation was performed with 1 mL of a solution prepared with a radiopaque contrast medium and sodium hypochlorite 5.25%. Digital images were taken, and a calibrated reader determined the presence or absence of gas bubbles in the middle and cervical thirds of the root canal system.

Results: When a patency file was not used, 40% of the root canals presented gas bubbles; when a patency file was used, 25% of the cases exhibited gas bubbles.

Conclusions: The presence of gas bubbles in the middle and cervical thirds of the root canal system during cleaning and shaping procedures is a common finding regardless of whether a patency file was used, although maintaining apical patency significantly leads to minimizing the presence of gas bubbles in big canals (P < .05).
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http://dx.doi.org/10.1016/j.joen.2011.10.026DOI Listing
February 2012
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