A finite element study on stress distribution of two different attachment designs under implant supported overdenture

Objective

This study aimed to evaluate stress patterns generated within implant-supported mandibular overdentures retained by two different attachment types: ball and socket and locator attachments.

Materials and methods

Commercial CAD/CAM and finite element analysis software packages were utilized to construct two 3D finite element models for the two attachment types. Unilateral masticatory compressive loads of 50, 100, and 150 N were applied vertically to the overdentures, parallel to the longitudinal axes of the implants. Loads were directed toward the central fossa in the molar region of each overdenture, that linear static analysis was carried out to find the generated stresses and deformation on each part of the studied model.

Results

According to FEA results the ball attachment neck is highly stressed in comparison to the locator one. On the other hand mucosa and cortical bone received less stresses under ball and socket attachment.

Conclusions

Locator and ball and socket attachments induce equivalent stresses on bone surrounding implants. Locator attachment performance was superior to that of the ball and socket attachment in the implants, nylon caps, and overdenture. Locator attachments are highly recommended and can increase the interval between successive maintenance sessions.     

Negative biomarker-based male fertility evaluation: sperm phenotypes associated with molecular-level anomalies

Biomarker-based sperm analysis elevates the treatment of human infertility and ameliorates reproductive performance in livestock. The negative biomarker-based approach focuses on proteins and ligands unique to defective spermatozoa, regardless of their morphological phenotype, lending itself to analysis by flow cytometry (FC). A prime example is the spermatid specific thioredoxin SPTRX3/TXNDC8, retained in the nuclear vacuoles and superfluous cytoplasm of defective human spermatozoa. Infertile couples with high semen SPTRX3 are less likely to conceive by assisted reproductive therapies (ART) and more prone to recurrent miscarriage while low SPTRX3 has been associated with multiple ART births. Ubiquitin, a small, proteolysis-promoting covalent posttranslational protein modifier is found on the surface of defective posttesticular spermatozoa and in the damaged protein aggregates, the aggresomes of spermiogenic origin. Semen ubiquitin content correlates negatively with fertility and conventional semen parameters, and with sperm binding of lectins LCA (Lens culinaris agglutinin; reveals altered sperm surface) and PNA (Arachis hypogaea/peanut agglutinin; reveals acrosomal malformation or damage). The Postacrosomal Sheath WWI Domain Binding Protein (PAWP), implicated in oocyte activation during fertilization, is ectopic or absent from defective human and animal spermatozoa. Consequently, FC-parameters of PAWP correlate with ART outcomes in infertile couples and with fertility in bulls. Assays based on the above biomarkers have been combined into multiplex FC semen screening protocols, and the surface expression of lectins and ubiquitin has been utilized to develop nanoparticle-based bull semen purification method validated by field artificial insemination trials. These advances go hand-in-hand with the innovation of FC-technology and genomics/proteomics-based biomarker discovery.     

Clinical utility of dabigatran in United Arab Emirates: A pharmacovigilance study

Objectives:

To provide early data regarding clinical utility of dabigatran in Al-Ain, United Arab Emirates (UAE).

Methods:

This was an ethics approved retrospective cross sectional study. We retrieved a total of 76 patients who were using dabigatran from September to December 2014 in the Cardiology Clinic at Al-Ain Hospital, Al-Ain, UAE. The primary analysis was designed to test the frequency of bleeding events (rate) with dabigatran 75, 110, and 150 mg.

Results:

The mean age ± standard deviation of cohort was 67.9 ± 1.5 years (range; 29-98 years), composed of males (52.6%) with mean age of 66.3 ± 1.7 years, and females (47.4%) with mean age of 69.6 ± 1.1 years. The highest age group was those between 61-80 years (60.5%). Most comprised the age strata of ≤75 years (73.7%). The main indication for dabigatran use was atrial fibrillation. The rate of bleeding with dabigatran was 18/76 (23.7%), and melena was the leading cause of bleeding 8/76 (10.7%). The hospitalization rate was 67.1%, dabigatran withdrawal rate was 0.01%, and mortality rate was 6.5%. The cohort had exhibited incidences of minor bleeding with one fatal major bleeding, high co-morbidities, admission, and readmission, which was not directly linked to dabigatran. We did not identify any relation of death due to dabigatran.

Conclusion:

Dabigatran is a suitable alternative to warfarin obviating the need for repetitive international normalized ratio monitoring, however, it may need plasma drug monitoring.Atrial fibrillation (AF) is the most common cardiac arrhythmia that affects 1-1.5% of population worldwide.1 Atrial fibrillation prevalence increases with age, and rises from 0.7% in those between 55-59 years to 17.8% in those ≥85 years. Nearly 85% of patients with AF are aged >65 years old.2 The lifetime risk for the development of AF as demonstrated in the Framingham study was one in 4 for men and women aged ≥40 years,3 which pose certain concerns in countries with aging populations.4,5 In addition to this, hospitalization related to AF is alarmingly increasing.6 The risk of stroke in patients with AF is 5 folds, and systemic thromboembolism is 3 folds.7,8 Banerjee, et al9 has deployed stroke prevention score in patients with AF, however, the predictive value is of less magnitude. The European Society of Cardiology set estimation of stroke risk in patients with AF as per CHA₂DS₂-VASc score to determine the recommendation for initiating an oral anticoagulant,10 whereas in patients with CHA₂DS₂-VASc ≥2, HAS-BLED score can be used to assess the risk of bleeding, and commencement of anticoagulant.11Warfarin (vitamin K antagonist [VKA]) has proven efficacy in reducing the risk of stroke in patients with AF, however, it poses high bleeding incidences, emergency hospitalizations, unpredictable therapeutic effect, and multiple international normalized ratio (INR) tests leading to many limitations in its clinical utility.12 Novel oral anticoagulants (NOACs) are proved as effective anticoagulants in prevention of stroke in patients with AF. Novel oral anticoagulants were preferred in non-valvular AF, and do not require coagulation monitoring, however, strict adherence to approved indication is highly warranted.13 Dabigatran (Pradaxa^®), a competitive inhibitor of thrombin was approved in October 2010 by the United States of America Food and Drug Administration to reduce the risk of stroke, and systemic embolism in patients with non-valvular AF.14 A systematic review incorporated 6 economic reviews from diverse healthcare systems (USA, Canada, and United Kingdom) utilizing different economic models. It has suggested the benefit of dabigatran in patients with high-risk of stroke, high-risk of intra-cerebral hemorrhage, or suboptimal use of warfarin. The review outlined concerns on tolerability of dabigatran, adherence issues, and adverse consequences.15In comparison with warfarin, dabigatran 150 mg has shown low rates of stroke, and systemic embolism (dabigatran p<0.001 for superiority). However, both drugs exhibited comparable rates of major hemorrhage.16-18 Greater fatal, and non fatal bleeding events were reported with dabigatran than warfarin.19,20 A recent (2015) retrospective Medicare data analysis study20 on dabigatran’s safety highlighted that the incidence of bleeding was higher than with warfarin (33% versus 27%), major bleeding (9% versus 6%), and gastrointestinal bleeding (17% versus 10%). Intracranial hemorrhage occurred more often with warfarin than dabigatran (1.8% versus 0.6%).20 It has been documented that risks of major bleeding from dabigatran is high for patients with chronic kidney disease, and in African Americans.20 The Randomized Evaluation of Long-term Anticoagulant Therapy: Dabigatran versus warfarin-RE-LY studies18 have showed similar risk of bleeding with warfarin versus dabigatran in patients with non-valvular AF. This dictated the importance of age sub-group analysis in studies. In real clinical practice, patients from different countries may have more co-morbid conditions than those in the RE-LY study.21 The current available data around bleeding incidences from dabigatran is relevant to populations with diverse characteristics. Revealing the clinical utility of dabigatran in our Emirati population may demonstrate different perspectives. Therefore, we intend to provide early data around the clinical utility of dabigatran in United Arab Emirates (UAE) Emirati population.     

Correlation between expression of MMP-9 and MMP-3 in Helicobacter pylori infected patients with different gastroduodenal diseases

Background and study aims

Helicobacter pylori (H. pylori) has been implicated in the pathogenesis of most important gastro-duodenal diseases, such as gastritis, peptic ulcer disease (PUD) and gastric cancer. H. pylori upregulates the expression and activity of several matrix metalloproteinases (MMPs) in the gastric mucosa, but the role of MMP-3 and MMP-9 in infected patients with H. pylori have not been clearly defined yet. We examined mucosal MMP-3 and MMP-9 mRNA levels in gastric mucosa of H. pylori infected patients and evaluated the effects of virulence factors cagA and vacA allelic variants on these levels. We also determined correlation between mucosal MMP-3 and MMP-9 mRNA levels and types of disease.

Dorsal costo-vertebral joint as a rare localization of Staphylococcus aureus sepsis

Background

Septic arthritis of the costovertebral thoracic joint is a rare site infection. We report an isolated case of septic arthritis of the 10th costo-vertebral right joint with osteitis due to Staphylococcus aureus.

Serodiagnosis of Schistosoma mansoni infections in an endemic area of Burkina Faso: performance of several immunological tests with different parasite antigens

The performance of indirect haemagglutination assays (IHA), enzyme-linked immunosorbent assays (ELISA) and indirect immunofluorescent antibody tests (IFAT) were compared with 450 sera from a Schistosoma mansoni-endemic area in Burkina Faso. All participants in this survey provided at least one sample each of stool, urine and serum. From those with an egg-negative Kato-Katz thick smear, a second stool sample was examined. IHA was based on either extracts of adult S. mansoni worms (SmIHA) or S. japonicum egg antigen (SjIHA). For ELISA, three antigen preparations were used, namely: (i) soluble S. mansoni adult worm antigens (SWAP); (ii) soluble S. mansoni egg antigens (SEA); and (iii) a cationic exchange fraction of S. mansoni eggs (CEF6). IFAT was performed with S. mansoni male worm sections. Among the egg-excretors, the sensitivity of ELISA was high and egg antigens performed slightly better (SEA, 96%; CEF6, 97%) than worm antigen (94%). Sensitivity of IHA was satisfactory with homologous (Sm, >85%), but not heterologous (Sj, 56%) parasite antigen. In IFAT, the parenchyma-associated fluorescence showed high sensitivity (95%), but gut-associated fluorescence, which is known to be a sensitive diagnostic marker for schistosome-infected European travelers, was observed only in 76% of a sub-sample of 100 of the endemic sera. Among sera from egg-negative individuals, many gave positive reactions in several or all of the tests employed. These reactions (formally "false positive") are considered to represent true infections, since chemotherapy had not yet been delivered to this population. For the purpose of further surveys in Burkina Faso or other resource-poor settings, we suggest IHA as an accurate diagnostic test and propose to further improve its performance by including egg rather than worm antigens.     

Protective effect of chronic caffeine intake on gene expression of brain derived neurotrophic factor signaling and the immunoreactivity of glial fibrillary acidic protein and Ki-67 in Alzheimer’s disease

Alzheimer’s disease (AD) is a neurodegenerative disorder with progressive degeneration of the hippocampal and cortical neurons. This study was designed to demonstrate the protective effect of caffeine on gene expression of brain derived neurotrophic factor (BDNF) and its receptor neural receptor protein-tyrosine kinase-β (TrkB) as well as glial fibrillary acidic protein (GFAP) and Ki-67 immunoreactivity in Aluminum chloride (AlCl₃) induced animal model of AD. Fifty adult rats included in this study were classified into 5 group (10 rats each); negative and positive control groups (I&II), AD model group (III), group treated with caffeine from the start of AD induction (IV) and group treated with caffeine two weeks before AD induction (V). Hippocampal tissue BDNF and its receptor (TrkB) gene expression by real time RT-PCR in addition to immunohistochemical study of GFAP and Ki67 immunoreactivity were performed for all rats in the study. The results of this study revealed that caffeine has protective effect through improving the histological and immunohistochemical findings induced by AlCl₃ as well as BDNF and its receptor gene expression. It could be concluded from the current study, that chronic caffeine consumption in a dose of 1.5 mg/kg body weight daily has a potentially good protective effect against AD.