Correlations between effective permeability and marrow contact channels surface of vertebral endplates

Homeostasis of the intervertebral disc relies on nutrient supply and waste clearance through the dense capillary network that is in contact with the cartilage endplate (CEP). We developed a micro-computerized tomography (micro-CT) method to quantify the marrow contact channel surface (MCCS) with the CEP and to validate the hypothesis according to which MCCS was correlated to the effective permeability of the vertebral endplate (VEP) and influenced by the mechanical stimuli. The influence of compression loading on local vascularization was investigated. Six 4-week-old skeletally immature pigs were instrumented with left pedicle screws and rod at both T5-T6 and L1-L2 levels to create asymmetrical spine tethers. After 3 months of growth, three cylindrical specimens of the VEP (one central and two lateral right and left) were obtained from both the instrumented and the control levels. We used a previously validated method for measuring permeability. Micro-CT analysis (resolution 12 mu m) yielded a gray-scale 2D-image of the discal end of each specimen converted into a binary 2D-image to derive the MCCS. Correlations between MCCS and effective permeability were assessed. Effective permeability and MCCS were significantly decreased compared to the control group especially on the tethered side (-41..5%, p = 0.004 and -52.5%, p = 0.0009, respectively). Correlations were significant and showed maximal value (r(2) = 0.430, p < 0.0001) on the tethered side involving maximal compressive loadings. Mechanical stimuli, due to unbalanced growth, altered the vascularization and the convective properties of the CEP. The cascade of mechanobiological events should offer perspectives for research on disc degeneration and attempted treatment. (C) 2010 Orthopaedic Research Society

Pediatric orthopedic surgery in humanitarian aid

Pediatric orthopedic surgery in humanitarian aid is conducted mainly in cooperation with emerging countries. Each mission is different, and depends on numerous parameters such as the country, the frequency of such missions, the pathologies encountered, the local structure and team, and the non-governmental organization (NGO) involved. Pathologies vary in etiology (tuberculosis, poliomyelitis) and severity. Each mission requires the presence of an experienced surgeon. Working conditions are often rudimentary. Surgical indications should be restricted to procedures that are going to be effective, with minimal postoperative complications, without any surgical "acrobatics". Teaching should be in association with the local university, and adapted to local needs. Mission objectives need to be realistic. Surgical indications should be adapted to local conditions, and the surgeon needs to be able to say "no" to procedures involving undue risk. The surgeon on mission should cooperate with local teams and be able to adapt to unusual situations. Assessment of results is essential to improving efficacy and evaluating the success of the mission

Trocar Site Recurrence after Laparoscopic Cholecystectomy for Unsuspected Isolated Gallbladder Metastasis of Melanoma: A Case Report and Review of the Literature

Cutaneous melanoma can metastasize to almost any organ, including in-transit metastases, lymph nodes, liver, lungs, brain, and bones. Spread to the gastrointestinal tract is less common and generally concerns the small bowel, colon, and stomach. Gallbladder involvement is rarer, and only few cases describe it as the sole site of metastasis upon diagnosis. Melanoma metastases to the gallbladder are usually detected on staging or surveillance imaging, as patients usually show few or no symptoms. In resectable stage IV melanoma patients, complete surgical resection appears to improve the prognosis. However, due to the rarity of isolated gallbladder metastasis of melanoma, there are no guidelines regarding the optimal surgical approach (endoscopic or open cholecystectomy). Here, we report the case of isolated gallbladder melanoma metastasis found after laparoscopic cholecystectomy performed in a 46-year-old female patient with no known history of cancer presenting with acute cholecystitis symptoms. Six weeks after surgery, the patient developed trocar site recurrence. This case highlights the importance of a planned and open surgery for resectable melanoma metastases rather than a laparoscopic approach

Small but crucial : the novel small heat shock protein Hsp21 mediates stress adaptation and virulence in Candida albicans

Peer reviewedPublisher PD

Five-year outcomes of the First Distal Uninstrumented Vertebra after posterior fusion for Adolescent Idiopathic Scoliosis Lenke 1 or 2

BACKGROUND: Tilt of the First Distal Uninstrumented Vertebra (FDUV) reflects changes in the main curve and compensatory lumbar curve after posterior fusion to treat thoracic Adolescent Idiopathic Scoliosis (AIS). HYPOTHESIS: FDUV tilt 5 years or more post-fusion depends chiefly on reduction of the main curve and on other factors such as selection of the last instrumented vertebra. MATERIAL AND METHOD: A multicenter retrospective cohort of 182 patients with Lenke 1 or 2 AIS treated with posterior instrumentation and followed up for a mean of 8 years and a minimum of 5 years was studied. The patients were divided into two groups based on whether tilt of the upper endplate of the FDUV was ≤5° or >5°at last follow-up. Variables associated with tilt were identified by multiple logistic regression. RESULTS: Six variables were significantly associated with FDUVtilt: percentage of correction at last follow-up, correction loss, lumbar modifier B, number of instrumented vertebrae, inclusion within the instrumentation of the distal neutral vertebra, and inclusion within the instrumentation of the lowest vertebra intersected by the central sacral vertical line. DISCUSSION AND CONCLUSION: The main variables associated with FDUVtilt ≤5° were a final correction percentage ≥60% and absence of correction loss between the postoperative period and last follow-up. Given the stable reduction provided by contemporary instrumentations, we recommend selective thoracic fusion of Lenke 1 or 2 AIS with lumbar modifiers A, B, and C. The lowest instrumented vertebra should be either the neutral vertebra or the vertebra intersected by the central sacral vertical line if it is distal to the neutral vertebra. LEVEL OF EVIDENCE IV: Retrospective multicenter study

The stellar halo of the Galaxy

Stellar halos may hold some of the best preserved fossils of the formation history of galaxies. They are a natural product of the merging processes that probably take place during the assembly of a galaxy, and hence may well be the most ubiquitous component of galaxies, independently of their Hubble type. This review focuses on our current understanding of the spatial structure, the kinematics and chemistry of halo stars in the Milky Way. In recent years, we have experienced a change in paradigm thanks to the discovery of large amounts of substructure, especially in the outer halo. I discuss the implications of the currently available observational constraints and fold them into several possible formation scenarios. Unraveling the formation of the Galactic halo will be possible in the near future through a combination of large wide field photometric and spectroscopic surveys, and especially in the era of Gaia.Comment: 46 pages, 16 figures. References updated and some minor changes. Full-resolution version available at http://www.astro.rug.nl/~ahelmi/stellar-halo-review.pd

Galaxy Formation Theory

We review the current theory of how galaxies form within the cosmological framework provided by the cold dark matter paradigm for structure formation. Beginning with the pre-galactic evolution of baryonic material we describe the analytical and numerical understanding of how baryons condense into galaxies, what determines the structure of those galaxies and how internal and external processes (including star formation, merging, active galactic nuclei etc.) determine their gross properties and evolution. Throughout, we highlight successes and failings of current galaxy formation theory. We include a review of computational implementations of galaxy formation theory and assess their ability to provide reliable modelling of this complex phenomenon. We finish with a discussion of several "hot topics" in contemporary galaxy formation theory and assess future directions for this field.Comment: 58 pages, to appear in Physics Reports. This version includes minor corrections and a handful of additional reference

Assessment of diversity of native species produced in forest nurseries of Rio de Janeiro State

AbstractThe objective of this paper was to evaluate the diversity of native species produced by nurseries in the State of Rio de Janeiro. The diagnostic and survey were conducted during the months of February, March and April of the year 2010, the research included all nurseries that produced seedlings of Atlantic Forest species. The fieldwork consisted of visits to the 70 surveyed nurseries, in which a list of the species produced in the nursery was requested and the seedling production manager was interviewed, filling in a questionnaire covering various topics related to seedlings production. We observed 277 forest species native from the Atlantic Forest produced in the nurseries. In average, the nurseries produce 56 different native species. The total diversity of native species produced in the State of Rio de Janeiro is low, as well as the mean diversity, since more than half of the nurseries work with a list of 50 or fewer species, what is insufficient considering the diversity of forest species that occur in the different vegetation types of the state.Keywords: Forest seedlings; forest restoration; Atlantic Forest.O objetivo deste trabalho foi avaliar a diversidade de espécies florestais nativas produzidas nos viveiros do estado do Rio de Janeiro. O levantamento e diagnóstico foram realizados durante os meses de fevereiro, março e abril de 2010, sendo incluídos os viveiros que produziam mudas de espécies florestais da Mata Atlântica. O trabalho de campo consistiu em visitas a 70 viveiros florestais, nos quais foi requerida a lista das espécies produzidas e realizada entrevista com o responsável, sendo preenchido um questionário englobando diversos temas relacionados à produção de mudas. Foram observadas 277 espécies florestais nativas da Mata Atlântica sendo produzidas nos viveiros, que, em média, trabalham com 56 espécies nativas. A diversidade total de espécies florestais da Mata Atlântica produzidas nos viveiros do Estado do Rio de Janeiro é baixa, assim como a diversidade média, já que mais da metade dos viveiros trabalha com uma listagem de 50 ou menos espécies, número insuficiente considerando a diversidade de espécies florestais presentes nas diferentes formações vegetais do estado.Palavras-chave: Mudas florestais; restauração florestal; Mata Atlântica. AbstractAssessment of diversity of native species produced in forest nurseries of Rio de Janeiro State. The objective of this paper was to evaluate the diversity of native species produced by nurseries in the State of Rio de Janeiro. The diagnostic and survey were conducted during the months of February, March and April of the year 2010, the research included all nurseries that produced seedlings of Atlantic Forest species. The fieldwork consisted of visits to the 70 surveyed nurseries, in which a list of the species produced in the nursery was requested and the seedling production manager was interviewed, filling in a questionnaire covering various topics related to seedlings production. We observed 277 forest species native from the Atlantic Forest produced in the nurseries. In average, the nurseries produce 56 different native species. The total diversity of native species produced in the State of Rio de Janeiro is low, as well as the mean diversity, since more than half of the nurseries work with a list of 50 or fewer species, what is insufficient considering the diversity of forest species that occur in the different vegetation types of the state.Keywords: Forest seedlings; forest restoration; Atlantic Forest