Sorting of a nonmuscle tropomyosin to a novel cytoskeletal compartment in skeletal muscle results in muscular dystrophy

Tropomyosin (Tm) is a key component of the actin cytoskeleton and >40 isoforms have been described in mammals. In addition to the isoforms in the sarcomere, we now report the existence of two nonsarcomeric (NS) isoforms in skeletal muscle. These isoforms are excluded from the thin filament of the sarcomere and are localized to a novel Z-line adjacent structure. Immunostained cross sections indicate that one Tm defines a Z-line adjacent structure common to all myofibers, whereas the second Tm defines a spatially distinct structure unique to muscles that undergo chronic or repetitive contractions. When a Tm (Tm3) that is normally absent from muscle was expressed in mice it became associated with the Z-line adjacent structure. These mice display a muscular dystrophy and ragged-red fiber phenotype, suggestive of disruption of the membrane-associated cytoskeletal network. Our findings raise the possibility that mutations in these tropomyosin and these structures may underpin these types of myopathies

Clostridia Initiate Heavy Metal Bioremoval in Mixed Sulfidogenic Cultures

Sulfate reducing bacteria (SRB) are widely used for attenuating heavy metal pollution by means of sulfide generation. Due to their low metal tolerance, several SRB species depend on associated bacteria in mixed cultures to cope with metal-induced stress. Yet the identity of the SRB protecting bacteria is largely unknown. We aimed to identify these associated bacteria and their potential role in two highly metal-resistant mixed SRB cultures by comparing bacterial community composition and SRB activity between these cultures and two sensitive ones. The SRB composition in the resistant and sensitive consortia was similar. However, whereas the SRB in the sensitive cultures were strongly inhibited by a mixture of copper, zinc, and iron, no influence of these metals was detected on SRB growth and activity in the resistant cultures. In the latter, a Gram-positive population mostly assigned to Clostridium spp.initiated heavy metal bioremoval based on sulfide generation from components of the medium (mainly sulfite) but not from sulfate. After metal levels were lowered by the Clostridium spp. populations, SRB started sulfate reduction and raised the pH of the medium. The combination of sulfite reducing Clostridium spp. with SRB may improve green technologies for removal of heavy metals

Root Canal Anatomy of Maxillary and Mandibular Teeth

It is a common knowledge that a comprehensive understanding of the complexity of the internal anatomy of teeth is imperative to ensure successful root canal treatment. The significance of canal anatomy has been emphasized by studies demonstrating that variations in canal geometry before cleaning, shaping, and obturation procedures had a greater effect on the outcome than the techniques themselves. In recent years, significant technological advances for imaging teeth, such as CBCT and micro-CT, respectively, have been introduced. Their noninvasive nature allows to perform in vivo anatomical studies using large populations to address the influence of several variables such as ethnicity, aging, gender, and others, on the root canal anatomy, as well as to evaluate, quantitatively and/or qualitatively, specific and fine anatomical features of a tooth group. The purpose of this chapter is to summarize the morphological aspects of the root canal anatomy published in the literature of all groups of teeth and illustrate with three-dimensional images acquired from micro-CT technology.info:eu-repo/semantics/publishedVersio

Ultrastructural changes in feline dental pulp with periodontal disease

A light and transmission electron microscopic study was conducted on dental pulp on cats suffering periodontal disease. After extraction, pulp tissues were fixed and embedded in Epon-Araldite. Thick layers of predentin (50 μm) and odontoblasts (30 μm)

Histological Study of the Effects of Ibuprofen on Acute Apical Inflammation Following Root Canal Therapy in Cats

Postoperative pain following Root Canal Therapy (RCT) is the common problem for patients,"ndentist and dental staff. Regardless of cause it appears that postoperative pain and discomfort is related to"nperiapical inflammation. The purpose of this study was to investigate histologically the effect of"nIbuprofen on acute apical inflammation following RCT. on cat. Fifty-six cuspids teeth of 14 cats were"ndivided into three groups, 6 cats for experimental group, 6 cats for positive control group and 2 cats for"nnegative control group. In first group, to anesthesize the animals each cat received 10 mg/kg Ibuprofen"n36 hours before RCT and repeated every 24 hours. In second group RCT was performed in 24 cat teeth"nwithout any prescription. In negative control groups 2 cats, no RCT were done."nFollowing vital perfusion, in interval of 6, 12, 24 hours, samples were post fixed in 10% formalin and"nfive micron sections were prepared, and stained with H&E and studied under the Mann Whitney"nparameter test. Infilteration of inflamatory cells in 6 hours interval in experimental group was"nsignificantly less than two control groups. In 12 hours samples, however, inflammation in experimental"ngroup reduced, but it was not significant. In 24 hours samples there was no significant difference"nbetween experimental groups and controls. The result of this in-vivo study shows prescription of"nIbuprofen before root canal therapy can reduce inflammatory reaction

A Comparison between Amalgam and MTA in Repairing Furcal Perforation

Objective: The purpose of this study was to investigate the histological response to delib-erate perforation repaired using amalgam or MTA either immediately or with delay on cats’ molars.Materials and Methods: Twenty-eight molar teeth from four cats were used in this ex-perimental randomized study. After preparing the access cavity, the floor of pulp cham-bers were deliberately perforated with a round bur No. 5. The teeth were randomly divided into four groups of seven. In groups one and two,the perforation was immediately sealed with amalgam and MTA, respectively. In groups three and four, the perforations were leftexposed to saliva for six weeks and then sealed with amalgam or MTA. The animals were sacrificed four months later and the specimens processed. The samples were blindly exam-ined for inflammatory reaction and healing process under light microscope. The data were analyzed with Mann-Whitney U and Fisher exact tests.Results: The type of the materials used has no significant effect on the severity of in-flammation; while, immediate or delayed repair of furcal perforation has, and immediate application of, MTA produced less inflammation than that of amalgam (P<0.05). No dif-ferences were found in vasodilatation, abscess formation or healing process between the immediate and the delayed repair groups (P=0.13).Conclusion: MTA is a more suitable material than amalgam for perforation repair, par-ticularly when used immediately after perforation