Micro-computed tomography and histology to explore internal morphology in decapod larvae

Traditionally, the internal morphology of crustacean larvae has been studied using destructive techniques such as dissection and microscopy. The present study combines advances in microcomputed tomography (micro-CT) and histology to study the internal morphology of decapod larvae, using the common spider crab (Maja brachydactyla Balss, 1922) as a model and resolving the individual limitations of these techniques. The synergy of micro-CT and histology allows the organs to be easily identified, revealing simultaneously the gross morphology (shape, size, and location) and histological organization (tissue arrangement and cell identification). Micro-CT shows mainly the exoskeleton, musculature, digestive and nervous systems, and secondarily the circulatory and respiratory systems, while histology distinguishes several cell types and confirms the organ identity. Micro-CT resolves a discrepancy in the literature regarding the nervous system of crab larvae. The major changes occur in the metamorphosis to the megalopa stage, specifically the formation of the gastric mill, the shortening of the abdominal nerve cord, the curving of the abdomen beneath the cephalothorax, and the development of functional pereiopods, pleopods, and lamellate gills. The combination of micro-CT and histology provides better results than either one alone.Financial support was provided by the Spanish Ministry of Economy and Competitiveness through the INIA project (grant number RTA2011-00004-00-00) to G.G. and a pre-doctoral fellowship to D.C. (FPI-INIA)

Tannerella forsythia, a periodontal pathogen entering the genomic era

Several questions need to be addressed to evaluate whether Tannerella forsythia is to be considered a periodontal pathogen. T. forsythia has been detected in periodontal health and disease, so could it be a pathogen? The species was not detected in many studies despite finding other putative pathogens, so could it be important in pathogenicity? The challenges of working with T. forsythia include its fastidious and anaerobic growth requirements for cultural detection. Thus, studies associating T. forsythia with periodontal and other oral infections have used noncultural approaches (immunoassays and DNA-based assays) in addition to cultural approaches. We feel the timing of this review represents an interesting transition period in our understanding of the relationships of species with infection. Information from the recently released full genome sequence data of T. forsythia will provide new approaches and tools that can be directed to assess pathogenicity. Furthermore, molecular assessment of gene expression will provide a new understanding of the pathogenical potential of the species, and its effect on the host. T. forsythia, was described in reviews focusing on periodontal pathogens associated with herpesvirus detection (200), species for which genome projects were underway (41), members of polybacterial periodontal pathogenic consortium (91), and participants in periodontal microbial ecology (202). We will describe the history, taxonomy, and characteristics of T. forsythia, and related species or phylotypes in the genus Tannerella. To assess the pathogenic potential of T. forsythia, we first describe species associations with periodontal and other infections, including animal models, as has been the traditional approach arising from Koch’s postulates (203). Criteria for pathogenicity were expanded to incorporate sequence- derived information (58), and again more recently to include molecular signatures of pathogens and disease (170). We used sequence and genome-derived information, in addition to biofilm, pathogenic mediators, and host responses, to further explore the pathogenic potential of T. forsythia

Roentgenographic interpretation of experimentally produced bony lesions using radiovisiography and conventional radiography - update

The aim of this investigation was to evaluate RadioVisioGraphy (RVG) and conventional radiography using Ektaspeed films in the detection of mechanically created bony lesion and determine the difference in identification of both buccal and lingual lesions. Thirty goat mandibles were used. Artificial lesion were created in the area of the body of mandible using round burs #2, #4, #6 and #8 round. Four defects were created posteriorly in between the teeth of each jaw on the buccal aspects in 30 jaws and the lingual side in another 30 mandibles. Periapica radiographs were made using RVG and conventional radiography. Results displayed a statistically significant difference between the size of bur and the detection of bony lesion regardless of the imaging type. (P>0.005). Defects on the lingual were significantly well depicted than those on the buccal at P>0.005. RVG demonstrated superiority in its diagnostic accuracy (p>0.005). It is concluded that RVG has significantly a better diagnostic value in the detection of early pathological conditions.King Saud Universit

Technical quality of root fillings performed by undergraduate students in Saudi Arabia.

Aim To evaluate the technical quality of root fillings performed in the undergraduate clinic of the Dental College, King Saud University, Saudi Arabia and to compare the technical quality of root canal treatment between the 4th- and 5th-year students. Methodology A random sample of 710 records of patients who had received dental treatment by undergraduate students at the College of Dentistry (Malaz University Campus), between the years of 2005–2008, was investigated. The final sample consisted of 550 root filled teeth in 459 patients. For each root filled tooth, at least three periapical radiographs were examined: preoperative, working length determination and postoperative. The length, density and taper of root fillings, as well as the presence of procedural errors, were recorded. ‘Acceptable’ filling quality was defined as having adequate length, density and taper with the absence of any procedural error. Results were evaluated statistically using chi-square test. Results One hundred and twenty-five of 550 root filled teeth (23%) had a root filling that was classified as ‘acceptable’. There was no statistical significant association between the 4th- and 5th-year students in terms of length (P = 0.134), density (P = 0.081) and taper (P = 0.590). Seventy-five (14%) treated teeth had ledges, 40 (7%) had apical transportation and 37 (7%) had apical root perforation. Ledges had significant association with the level of student (P < 0.0001) and were greater in the cases of 4th-year students (18%) compared to the 5th-year students (8%), whilst root perforations had also significant association with level of students (P = 0.016) and were more in the 5th-year cases (3%) compared to the 4th-year cases (0.3%). Conclusions The technical quality of root fillings placed by undergraduate dental students was classified as ‘acceptable’ in 23% of cases. There was little difference between 4th- and 5th-year students in the overall quality of root fillings.King Saud Universit

Gut Microbiota Dynamics in Relation to Long-COVID-19 Syndrome: Role of Probiotics to Combat Psychiatric Complications

Increasing numbers of patients who recover from COVID-19 report lasting symptoms, such as fatigue, muscle weakness, dementia, and insomnia, known collectively as post-acute COVID syndrome or long COVID. These lasting symptoms have been examined in different studies and found to influence multiple organs, sometimes resulting in life-threating conditions. In this review, these symptoms are discussed in connection to the COVID-19 and long-COVID-19 immune changes, highlighting oral and psychiatric health, as this work focuses on the gut microbiota’s link to long-COVID-19 manifestations in the liver, heart, kidney, brain, and spleen. A model of this is presented to show the biological and clinical implications of gut microbiota in SARS-CoV-2 infection and how they could possibly affect the therapeutic aspects of the disease. Probiotics can support the body’s systems in fighting viral infections. This review focuses on current knowledge about the use of probiotics as adjuvant therapies for COVID-19 patients that might help to prevent long-COVID-19 complications