Is carbamazepine less effective in the treatment of trigeminal neuralgia when prescribed by oral and maxillofacial surgeons?

Carbamazepine therapy is generally suggested as a first line of treatment for patients with idiopathic trigeminal neuralgia (ITN). This study was intended to investigate patient compliance and effects of carbamazepine in a group of ITN patients referred to oral and maxillofacial surgeons. A total of 19 patients with ITN who were taking carbamazepine as recommended and were unlikely to go into spontaneous remission were analyzed in a retrospective study. The following criteria were used for the assessment: pain-free periods, success, recurrence and failure rate, side effects, and discontinuation of the treatment. Pain relief was recorded in 16 patients with pain-free periods of 1 to 48 mo. Pain recurred in 11 patients within 1 to 30 mo. Side effects were recorded in six patients. The treatment was discontinued in 13 patients for various reasons. At the last visit, the treatment was successful in six patients with pain-free periods of 6 to 48 mo. It is concluded that the carbamazepine treatment of patients with ITN referred to oral and maxillofacial surgeons should not be expected to be successful as generally accepted. Since a relatively high percentage of patients were reluctant to take drugs, a new treatment scheme for patients with ITN referred to an oral and maxillofacial surgeon was suggested.     

Anodal vs cathodal stimulation of motor cortex: a modeling study.

OBJECTIVE: To explore the effects of electrical stimulation performed by an anode, a cathode or a bipole positioned over the motor cortex for chronic pain management. METHODS: A realistic 3D volume conductor model of the human precentral gyrus (motor cortex) was used to calculate the stimulus-induced electrical field. The subsequent response of neural elements in the precentral gyrus and in the anterior wall and lip of the central sulcus was simulated using compartmental neuron models including the axon, soma and dendritic trunk. RESULTS: While neural elements perpendicular to the electrode surface are preferentially excited by anodal stimulation, cathodal stimulation excites those with a direction component parallel to its surface. When stimulating bipolarly, the excitation of neural elements parallel to the bipole axis is additionally facilitated. The polarity of the contact over the precentral gyrus determines the predominant response. Inclusion of the soma-dendritic model generally reduces the excitation threshold as compared to simple axon model. CONCLUSIONS: Electrode polarity and electrode position over the precentral gyrus and central sulcus have a large and distinct influence on the response of cortical neural elements to stimuli. SIGNIFICANCE: Modeling studies like this can help to identify the effects of electrical stimulation on cortical neural tissue, elucidate mechanisms of action and ultimately to optimize the therapy.     

Heart remodeling produced by aortic stenosis promotes cardiomyocyte apoptosis mediated by collagen V imbalance

Cardiac remodeling (CR) is a structural change of the heart due to chronic hemodynamic overload related to changes in both myocyte and extracellular matrix (ECM). We investigated that the imbalance of collagen V promotes cardiomyocyte apoptosis that contributes to heart failure and cell death. Aortic stenosis was induced surgically and male Wistar rats were randomized to 18 weeks (Sham 18?w, n?=?12; AoS 18?w, n?=?12) and severe of heart failure (Sham HF, n?=?12; AoS HF, n?=?12) groups. Functional and structural echocardiogram, immunohistochemistry for Ki-67, TUNEL assay and Immunofluorescence for collagen were performed. Our main results were: (1) Progressive reduction of cardiac functional capacity due to cardiac remodeling with decreased eject fraction in heart failure; (2) Imbalance of collagen deposition with increased, crowded and irregular collagen I in situ expression; (3) Dysregulation of dynamic control of collagen fibers with exposed epitopes of collagen V; (4) Additional apoptosis that are dependent to cardiac injury. The collagen V expression in cardiac remodeling is for the first time described and may be related to additional apoptosis and autoimmune response. Our findings suggest a critical role of collagen V in cardiac remodeling to modulate and promote heart failure and death.     

The assessment of airbag deployment and seatbelt use in preventing facial injuries

This study aimed to determine the effectiveness of airbags and seatbelts in the prevention of facial fractures and slight facial injuries in relation to the speed and kinetic energy experienced in frontal collisions. All cases of vehicle occupants who had been in frontal collisions and had subsequently been examined in the Institute for Emergency Medical Assistance and the Clinical Center of Montenegro in 2017 were analyzed. There were 29 cases of facial fractures (Group 1), 35 cases of slight facial injuries (including nondisplaced nasal fractures) (Group 2), and 26 cases of occupants who had suffered no facial injuries (control Group 3). In all assessed cases all of the subjects had been wearing a seatbelt and the airbag had deployed at the time of impact. A frontal collision is defined as a collision in which the principal force acts within a range of 90° from the longitudinal axis of the vehicle. Using the mass and the speed of the vehicles, the total kinetic energy (KE) of all frontal collisions being analyzed was calculated. The cut-off value of total KE in frontal collisions that were associated with either facial fractures or slight facial injury was estimated using a receiver operating characteristic (ROC) curve. The cut-off amounts of KE were then used to calculate the barrier equivalent velocity (BEV). The BEV for a vehicle of average mass was estimated to be 55.7 km/h (34.6 mph) in Group 1, and 49.2 km/h (30.6 mph) in Group 2. Airbags and seatbelts are effective in preventing facial injuries in vehicles of average mass that are traveling at speeds under 49.2 km/h (30.6 mph) at the point of impact, but they do not protect from facial fractures when the vehicle speed exceeds 55.7 km/h (34.6 mph).     

Gastrin and antral G cells in course of Helicobacter pylori eradication： Six months follow up study

ABM: To assess long-term effects of Helicobacter pylori (H pylori) eradication on antral G cell morphology and function in patients with and without duodenal ulcer (DU). METHODS: Consecutive dyspeptic patients referred to the endoscopy entered the study. Out of 39 H pylori positive patients, 8 had DU (Hpylori+DU) and 31 gastritis (Hpylori +G). Control groups consisted of 11 uninfected dyspeptic patients (CG1) and 7 healthy volunteers (CG2). Basal plasma gastrin (PGL), antral tissue gastrin concentrations (ATGC), immunohistochemical and electron microscopic characteristics of G cells were determined, prior to and 6 mo after therapy. RESULTS: We demonstrated elevated PGL in infected patients compared to uninfected controls prior to therapy. Elevated PGL were registered in all H pylori+patients (H pylori +DU: 106.78±22.72 pg/mL, H pylori+G: 74.95±15.63, CG1: 68.59±17.97, CG2: 39.24±5.59 pg/mL, P<0.01). Successful eradication (e) therapy in H pylori+patients lead to significant decrease in PGL (H pylori+DU:59.93±9.40 and H pylori+Ge: 42.36±10.28 pg/mL, P<0.001). ATGC at the beginning of the study were similar in infected and uninfected patients and eradication therapy lead to significant decrease in ATGC in H pylori+gastritis, but not in DU patients. In the H pylori+DU patients, the mean number of antral G cells was significantly lower in comparison with all other groups (P<0.01), but after successful eradication was close to normal values found in controls. By contrast, G cell number and volume density were significantly decreased (P<0.01) in H pylori+Ge group after successful eradication therapy (294±32 and 0.31±0.02, respectively), in comparison to values before eradication (416±40 and 0.48±0.09). No significant change of the G cell/total endocrine cell ratio was observed during the 6 mo of follow up in any of the groups. A reversible increase in G cell secretory function was seen in all infected individuals, demonstrated by a more prominent secretory apparatus. However, differences between DU and gastritis group were identified. CONCLUSION: H pylori infection induces antral G cell hyperfunction resulting in increased gastrin synthesis and secretion. After eradication therapy complete morphological and functional recovery is observed in patients with gastritis. In the DU patients some other factors unrelated to the H pylori infection influence antral G cell morphology and function.     

A model of the viscoelastic behavior of flowable resin composites prior to setting

Objective

The aim of this study is to develop fractional derivative models for the assessment of viscoelastic properties related to handling characteristics of dental resin composites belonging to two classes: flowable (Revolution Formula 2 and Filtek Ultimate) and posterior “bulk-fill” flowable base (Smart Dentin Replace).

Methods

Rheological measurements on all materials tested in this study were performed using dynamic oscillatory rheometer at temperature of 23 °C. A parallel plates module with a diameter of 20 mm was used to measure the properties of the resin composites tested. We developed two models to describe the obtained data: the generalized Newton model and the generalized Zener model (the so-called three parameter model). Both models contain fractional derivatives of Riemann–Liouville type. By determining the parameters of the model we were able to fit experimental data with high accuracy.

Results

Our results show that flowable “bulk-fill” resin-composite material (SDR) has distinct properties as compared to other two flowable resin composite materials (Revolution Formula 2 and Filtek Ultimate). Thus, previously found SDR properties as “bulk-fill” flowable base results in the fact that it is described by generalized Zener model (i.e., it has properties of solid like viscoelastic material).

Significance

Our model may be used to predict behavior of tested composites in different flow conditions. The SDR has initially small almost constant complex viscosity showing that it has good self-leveling property.