The relationship between the directions of myocardial bridges and of the branches of the coronary arteries in the human heart

Summary The variations of the direction of the myocardial bundles of the bridges over coronary arteries and branches were studied in relation to the direction of the vessels over which they are found. The investigation was performed on 82 hearts of individuals whose death was accidental and unrelated to cardiac disease. The hearts were obtained from cadavers of individuals of either sex and different racial groups, whose age ranged from 7 to 68 years. The angle between the direction of the musculature and of the vessels may explain why in some cases there is no change in the structure of the pontine portion of the wall.

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Relations entre l'axe des ponts myocardiques et les branches des artères coronaires chez l'homme

Résumé Ce travail étudie les variations de direction des fibres des ponts myocardiques et des artères coronaires et de leurs branches recouvertes par ces ponts. Les recherches ont été effectuées sur 82 coeurs de sujets décédés accidentellement et ne présentant aucune pathologie cardiaque. Ces coeurs ont été prélevés sur des sujets des deux sexes et de différents groupes raciaux dont l'âge s'échelonnait entre 7 et 68 ans. L'angle qui existe entre la direction des fibres musculaires et celle des vaisseaux peut expliquer pourquoi dans certains cas il n'y a pas de modification dans la structure de la paroi artérielle au niveau de sa portion pontée.

     

Genotoxicity of lavender oil,linalyl acetate,and linalool on human lymphocytes in vitro

The potential genotoxicity of lavender essential oil and its major components, linalool, and linalyl acetate, was evaluated in vitro by the micronucleus test on peripheral human lymphocytes. In the range of non‐toxic concentrations (0.5–100 μg/ml), linalyl acetate increased the frequency of micronuclei significantly and in concentration‐dependent manner; lavender oil did so only at the highest concentration tested, whereas linalool was devoid of genotoxicity. None of the tested substances led to an increase in nucleoplasmic bridges or nuclear buds frequency. These findings suggest that the mutagenic activity of lavender oil can be related to the presence of linalyl acetate, which seems to have a profile of an aneugenic agent. Environ. Mol. Mutagen. 52:69–71, 2011. © 2010 Wiley‐Liss, Inc.     

Aggrecan,versican and type VI collagen are components of annular translamellar crossbridges in the intervertebral disc

The aim of this study was to undertake a detailed analysis of the structure of the inter and intra-lamellar regions of the annulus fibrosus. A total of 30 newborn to 6 year-old lumbar ovine intervertebral discs (IVDs) were fixed and decalcified en-bloc to avoid differential swelling artifacts during processing and vertical mid-sagittal, and horizontal 4 μm sections were cut. These were stained with toluidine blue to visualise anionic proteoglycan (PG) species, H & E for cellular morphology and picro-sirius red (viewed under polarized light) to examine collagenous organization. Immunolocalisations were also undertaken using anti-PG core-protein and glycosaminoglycan (GAG) side chain antibodies to native chondroitin sulphate (CS), Δ C-4-S and C-6-S unsaturated stubs generated by chondroitinase ABC digestion of CS, keratan sulphate (KS), and with antibodies to type I, II, VI, IX and X collagens. Trans-lamellar cross bridges (TLCBs), discontinuities in annular lamellae’s which provide transverse interconnections, stained prominently with toluidine blue in the adult IVDs but less so in the newborn IVDs. In adult discs TLCBs were evident in both the posterior and anterior AF where they extended from the outermost annular lamellae almost to the transitional zone extending across as many as eight lamellar layers displaying a characteristic circuitous, meandering, serpentine type course. There were significantly fewer TLCBs in 2 week-old compared with skeletally mature sheep and there was a further increase from 2 to 6 years. Immunolocalisation of perlecan delineated blood vessels in the TLBs of the newborn but not adult IVDs extending into the mid AF. In contrast adult but not 2 week-old TLCBs were immunpositive for C-4-S, C-6-S, KS, aggrecan, versican and type VI collagen. The change in number and matrix components of the trans-lamellar cross bridges with skeletal maturity and ageing suggest that they represent an adaptation to the complex biomechanical forces occurring in the annulus fibrosus.     

Cost-effectiveness modeling of dental implant vs. bridge

Aims: We assess the cost-effectiveness of dental implant first-line strategy vs. fixed partial denture strategy in patients suffering from one single missing tooth.
Materials and methods: The model used a simulation decision framework over a 20-year period. Potential treatment switches can occur every 5 years. Transition probabilities come from literature, epidemiological reports or expert opinions. They have been programmed using specific distribution ranges to simulate the patients' and practice variability, and to take into account parameter uncertainty. Direct medical costs have been assessed according to a cost survey. Probabilistic sensitivity analyses were conducted using 5000 Monte-Carlo simulations, generating confidence intervals of model outcomes.
Results: We found that mean cost-effectiveness of the bridge strategy is higher than the implant strategy.
Conclusion: Implant as the first-line strategy appears to be the 'dominant' strategy, considering the lower overall costs and the higher success rate.     

Congenital dyserythropoiesis with intererythroblastic chromatin bridges and ultrastructurally-normal erythroblast heterochromatin: a new disorder

Two non-anaemic subjects, a father and daughter, with a new form of congenital dyserythropoiesis are reported. The features of their disorder are: (1) an abnormal blood film with basophilic stippling of red cells and oval macrocytes, (2) various dysplastic changes in the erythroblasts, including internuclear chromatin bridges, (3) ultrastructurally-normal erythroblast heterochromatin, (4) normal serum thymidine kinase activity, and (5) a probable autosomal dominant inheritance. The last three features distinguish this disorder from CDA type I.     

Structural and biochemical insights into the role of testis-expressed gene 14 (TEX14) in forming the stable intercellular bridges of germ cells

Intercellular bridges are a conserved feature of spermatogenesis in mammalian germ cells and derive from arresting cell abscission at the final stage of cytokinesis. However, it remains to be fully understood how germ cell abscission is arrested in the presence of general cytokinesis components. The TEX14 (testis-expressed gene 14) protein is recruited to the midbody and plays a key role in the inactivation of germ cell abscission. To gain insights into the structural organization of TEX14 at the midbody, we have determined the crystal structures of the EABR [endosomal sorting complex required for transport (ESCRT) and ALIX-binding region] of CEP55 bound to the TEX14 peptide (or its chimeric peptides) and performed functional characterization of the CEP55–TEX14 interaction by multiexperiment analyses. We show that TEX14 interacts with CEP55-EABR via its AxGPPx₃Y (Ala793, Gly795, Pro796, Pro797, and Tyr801) and PP (Pro803 and Pro804) sequences, which together form the AxGPPx₃YxPP motif. TEX14 competitively binds to CEP55-EABR to prevent the recruitment of ALIX, which is a component of the ESCRT machinery with the AxGPPx₃Y motif. We also demonstrate that a high affinity and a low dissociation rate of TEX14 to CEP55, and an increase in the local concentration of TEX14, cooperatively prevent ALIX from recruiting ESCRT complexes to the midbody. The action mechanism of TEX14 suggests a scheme of how to inactivate the abscission of abnormal cells, including cancer cells.Intercellular bridges are a distinct feature of spermatogenesis in mammalian germ cells. Although observations of intercellular bridges were reported more than 100 y ago, their molecular function is largely unknown and we have only recently begun to learn how they form at the molecular level. Interestingly, stable bridges have recently been recognized as providing a unique means of intercellular communication, because cytoplasmic molecules can pass through them (1). The loss of germ cell intercellular bridges disrupts spermatogenesis and causes sterility (2).The most direct method of cell-to-cell communication is to connect the separate cytosols of cells using a tunnel that allows macromolecules to pass from one cell to another. Various organisms achieve this type of direct intercellular transfer using tunneling nanotubes (3), intercellular bridges (also called ring canals) (1), and bacterial intercellular nanotubes (4). Somatic ring canals have also been found to equilibrate the levels of some proteins between connected cells in invertebrates such as Drosophila (5). Among these mechanisms, it has been shown that intercellular bridges having channels that are 0.5–3 μm in diameter are formed by the arrest of cell abscission at the final stage of cytokinesis in the germ cells of vertebrates (1).Whether the process of cell abscission is completed or not depends on the cell type. In the somatic cells of vertebrates, cell abscission occurs at the midbody (6), a structure that tethers two daughter cells. The midbody protein CEP55 plays a key role in recruiting the ALIX–endosomal sorting complex required for transport (ESCRT) I complex to the midbody (7, 8). After this event, ESCRT-III subunits, which have a membrane scission activity, are recruited (9–13). Alternatively, to inactivate cell abscission, TEX14, a testis-expressed gene and germ cell-specific component, is recruited to the midbody. It is essential for intercellular bridges and fertility in male mice (2), and has recently been identified as one of the susceptibility genes for testicular germ cell tumors (14).In germ cells, intercellular bridges are formed throughout spermatogenesis and the arrest of cell abscission is controlled precisely by a sophisticated interplay among the proteins TEX14, ALIX, TSG101 (expressed by tumor susceptibility gene 101; TSG101), and CEP55. Therefore, it is important to investigate how TEX14 safeguards intercellular bridges from the potentially damaging membrane scissor in germ cells. To understand the molecular mechanisms involved in this process, we have performed both structural and functional analyses of the CEP55–TEX14 interaction.     

Analytical Study of Porous Organosilicate Glass Films Prepared from Mixtures of 1,3,5- and 1,3-Alkoxysilylbenzenes

Organosilicate glass (OSG)-based porous low dielectric constant (low-k) films with different molar ratios of 1,3,5-tris(triethoxysilyl)benzene to 1,3-bis(triethoxysilyl)benzene bridging organic groups (1:3 and 1:7) were spin-on deposited, followed by a soft bake in air and N₂ at 150 °C and hard bake in air and N₂ at 400 °C. Non-ionic template (Brij^®30) concentrations were varied from 0 to 41 wt% to control the porosity of the films. The chemical composition of the matrix of the films was evaluated and discussed with the shrinkage of the film during the curing, refractive indices, mechanical properties, k-values, porosity and pore structure. The chemical composition of the film cured in both air and N₂-containing ambient were evaluated and compared. The benzene bridging groups containing films change their porosity (0 to 43%) but keep the pore size constant and equal to 0.81 nm when porosity is lower than 30%. The k-value decreases with increasing porosity, as expected. The films containing benzene bridge have higher a Young’s modulus than plasma-enhanced chemical vapor deposition (PECVD) methyl-terminated low-k films with the same porosity and show good hydrophobic properties after a hard bake and close to the values reported for 1,4-benzene-bridged films. The fabricated films show good stability after a long time of storage. However, the improvement of mechanical properties was lower than the values predicted by the published literature data. It was concluded that the concentration of 1,3,5-benzene bridges was below the stiffness threshold required for significant improvement of the mechanical properties. The films show UV-induced luminescence with a photon energy of 3.6 to 4.3 eV. The luminescence is related to the presence of oxygen-deficient-type defects or their combination with organic residues. The most intensive luminescence is observed in as-deposited and soft bake samples, then the intensity is reduced after a hard bake. It is assumed that the oxygen-deficient centers form because of the presence of Si–OC₂H₅ groups in the films and the concentration of these centers reduces when all these groups completely transformed into siloxane (Si–O–Si).     

Mechanical Performance of a Ballastless Track System for the Railway Bridges of High-Speed Lines: Experimental and Numerical Study under Thermal Loading

The mechanical performance of China Railway Track System type II (CRTS II) ballastless track suitable for High-Speed Railway (HSR) bridges is investigated in this project by testing a one-quarter-scaled three-span specimen under thermal loading. Stress analysis was performed both experimentally and numerically, via finite-element modeling in the latter case. The results showed that strains in the track slab, in the cement-emulsified asphalt (CA) mortar and in the track bed, increased nonlinearly with the temperature increase. In the longitudinal direction, the zero-displacement section between the track slab and the track bed was close to the 1/8L section of the beam, while the zero-displacement section between the track slab and the box girder bridge was close to the 3/8L section. The maximum values of the relative vertical displacement between the track bed and the bridge structure occurred in the section at three-quarters of the span. Numerical analysis showed that the lower the temperature, the larger the tensile stresses occurring in the different layers of the track structure, whereas the higher the temperature, the higher the relative displacement between the track system and the box girder bridge. Consequently, quantifying the stresses in the various components of the track structure resulting from sudden temperature drops and evaluating the relative displacements between the rails and the track bed resulting from high-temperature are helpful in the design of ballastless track structures for high-speed railway lines.     

A Partial Palatal Coverage Overdenture Retained by Zygomatic Implants

Prosthodontic rehabilitation of an atrophic edentulous maxilla can be challenging and is further complicated when multiple risk factors are present. Fixed prostheses require multiple implants for support/retention organized in biomechanically favorable positions in order to afford a good prognosis. Such suitable implant arrangements in an atrophic edentulous ridge can often be difficult to achieve. Removable prostheses require fewer implants for a favorable prognosis and can furthermore take advantage of the additional anatomical structures for support/retention. This clinical treatment will describe the fabrication of a partial palatal coverage overdenture retained by zygomatic implants.