Mucoid degeneration of the anterior cruciate Ligament: a case report

We report a case of mucoid degeneration of the anterior cruciate ligament (ACL). Mucoid degeneration of the ACL is a very rare cause of knee pain. There have been only some reported cases of mucoid degeneration of the ACL in the English literature. We reviewed previous reports and summarized clinical features and symptoms, including those found in our case. Magnetic Resonance Imaging is the most useful tool for differentiating mucoid degeneration of the ACL from an intraligamentous ganglion or other lesions in the knee joint. If this disease is considered preoperatively, it can be diagnosed easily based on characteristic findings.Key words: Anterior cruciate ligament, arthroscopy, Magnetic Resonance Imaging, mucoid degeneratio

Genetic Relations Between the Aves Ridge and the Grenada Back-Arc Basin, East Caribbean Sea

The Grenada Basin separates the active Lesser Antilles Arc from the Aves Ridge, described as a Cretaceous‐Paleocene remnant of the “Great Arc of the Caribbean.” Although various tectonic models have been proposed for the opening of the Grenada Basin, the data on which they rely are insufficient to reach definitive conclusions. This study presents, a large set of deep‐penetrating multichannel seismic reflection data and dredge samples acquired during the GARANTI cruise in 2017. By combining them with published data including seismic reflection data, wide‐angle seismic data, well data and dredges, we refine the understanding of the basement structure, depositional history, tectonic deformation and vertical motions of the Grenada Basin and its margins as follows: (1) rifting occurred during the late Paleocene‐early Eocene in a NW‐SE direction and led to seafloor spreading during the middle Eocene; (2) this newly formed oceanic crust now extends across the eastern Grenada Basin between the latitude of Grenada and Martinique; (3) asymmetrical pre‐Miocene depocenters support the hypothesis that the southern Grenada Basin originally extended beneath the present‐day southern Lesser Antilles Arc and probably partly into the present‐day forearc before the late Oligocene‐Miocene rise of the Lesser Antilles Arc; and (4) the Aves Ridge has subsided along with the Grenada Basin since at least the middle Eocene, with a general subsidence slowdown or even an uplift during the late Oligocene, and a sharp acceleration on its southeastern flank during the late Miocene. Until this acceleration of subsidence, several bathymetric highs remained shallow enough to develop carbonate platforms

Robust physical methods that enrich genomic regions identical by descent for linkage studies: confirmation of a locus for osteogenesis imperfecta

<p>Abstract</p> <p>Background</p> <p>The monogenic disease osteogenesis imperfecta (OI) is due to single mutations in either of the collagen genes ColA1 or ColA2, but within the same family a given mutation is accompanied by a wide range of disease severity. Although this phenotypic variability implies the existence of modifier gene variants, genome wide scanning of DNA from OI patients has not been reported. Promising genome wide marker-independent physical methods for identifying disease-related loci have lacked robustness for widespread applicability. Therefore we sought to improve these methods and demonstrate their performance to identify known and novel loci relevant to OI.</p> <p>Results</p> <p>We have improved methods for enriching regions of identity-by-descent (IBD) shared between related, afflicted individuals. The extent of enrichment exceeds 10- to 50-fold for some loci. The efficiency of the new process is shown by confirmation of the identification of the Col1A2 locus in osteogenesis imperfecta patients from Amish families. Moreover the analysis revealed additional candidate linkage loci that may harbour modifier genes for OI; a locus on chromosome 1q includes COX-2, a gene implicated in osteogenesis.</p> <p>Conclusion</p> <p>Technology for physical enrichment of IBD loci is now robust and applicable for finding genes for monogenic diseases and genes for complex diseases. The data support the further investigation of genetic loci other than collagen gene loci to identify genes affecting the clinical expression of osteogenesis imperfecta. The discrimination of IBD mapping will be enhanced when the IBD enrichment procedure is coupled with deep resequencing.</p

The mammalian centrosome and its functional significance

Primarily known for its role as major microtubule organizing center, the centrosome is increasingly being recognized for its functional significance in key cell cycle regulating events. We are now at the beginning of understanding the centrosome’s functional complexities and its major impact on directing complex interactions and signal transduction cascades important for cell cycle regulation. The centrosome orchestrates entry into mitosis, anaphase onset, cytokinesis, G1/S transition, and monitors DNA damage. Recently, the centrosome has also been recognized as major docking station where regulatory complexes accumulate including kinases and phosphatases as well as numerous other cell cycle regulators that utilize the centrosome as platform to coordinate multiple cell cycle-specific functions. Vesicles that are translocated along microtubules to and away from centrosomes may also carry enzymes or substrates that use centrosomes as main docking station. The centrosome’s role in various diseases has been recognized and a wealth of data has been accumulated linking dysfunctional centrosomes to cancer, Alstrom syndrome, various neurological disorders, and others. Centrosome abnormalities and dysfunctions have been associated with several types of infertility. The present review highlights the centrosome’s significant roles in cell cycle events in somatic and reproductive cells and discusses centrosome abnormalities and implications in disease

Pre-Mesozoic origin and paleogeography of blocks in the Caribbean, South Appalachian and West African domains and their impact on the post"variscan" evolution,

International audienceNew geodynamical data from West Africa bring consistent informations on the pre-Mesozoic reconstruction within a large area running from the western Sahara to the Colombian cordillera. These new data support a Neoproterozoic Ocean (WANO) between the Amazonian (AMC) and West African (WAC) cratons previously to the Iapetus and Rheic oceans. We delineate 31 blocs detached from the surrounding three continents: NAC (North American Craton), AMC and WAC. 7 came from the WAC margin, 7 from the NAC, 6 from the AMC and 11 from an intermediate volcano sedimentary domain (COB) built on a 1200-1000 Ma oceanic crust. These imbricated blocks formed a tight mosaic by the Hercynian/Alleghanian tectonic event which gave way to the Pangea super-continent. But, during the Atlantic Ocean opening these blocks began to move. They were separated by new oceanic basins. However, previously to the Pangea, blocks from the COB domain formed two sets of garlands located on the northwestern Gondwana margin. The northern one moved to the North until the Silurian to collide the NAC (Taconic tectonic event) meanwhile the southern one remains on the Gondwana margin. All together were gathered by the Carboniferous/Permian time. Then, the framework for the opening of the Atlantic Ocean was not totally disconnected from the "Variscan" collage and many variscan weakness zones were re-used as initial breaking zones. Beyond this tectonic impact, the pre-mesozoic assemblage allows us to compare this "Caribbean" island arc with another one: the Indonesian "Banda" arc. Thus, West Africa is a geological key area for correlations between the Caribbean, the Appalachian, the Brazilian "Nordeste" and the West European domains and for the understanding of the Atlantic Ocean opening process

Introduction to "Caribbean geosciences"

International audienceThis special issue includes papers covering various topics of importance in the Caribbean such as geodynamics, environmental evolutions and natural hazards (fig. 1). This collection of articles focuses in particular on geodynamic processes occurring along the Caribbean plate boundaries, on volcanic hazards and on flooding. Given the recently increased societal importance of these subjects, we hope that the regional geological community and the local policy makers and government officials of the Caribbean countries will find this a timely and valuable update regarding research advances on these topics. We decided to publish this issue following the Caribbean Geological Conference, which has been held every 3 years since 1955 and took place in Guadeloupe for its 19th meeting from the 21st to the 24th of March 2011

Chronostratigraphy and tectonic deformation of the North Ecuadorian-South Colombian offshore Manglares forearc basin

Forearc basins in convergent margins contain a nearly continuous record of sedimentation and deformation. Their chronostratigraphy reflects the manner in which the basin accommodates loads and vertical and horizontal motion caused by eustasy, tectonics and sedimentation during plate convergence. Along the North Ecuador and South Colombia (NESC) Margin (1 degrees-3.5 degrees N), thick Cenozoic sedimentary sequences accumulated over blocks of oceanic basement that accreted between the Late Cretaceous and Early Cenozoic, thus forming the onshore Borbon and Tumaco Basins and the offshore Pacific Frontal Basin. Based on morphology and seismic data analysis, the NESC forearc basin. named Manglares Basin, consists of five acoustic units of sedimentary nature (Units A-E) separated by unconformities (U1-U5), resting over the interpreted oceanic basement (Unit F). By integrating these data with regionally-compiled chronostratigraphic charts of the onshore Borbon and Tumaco Basins and the geology of Gorgona Island, we propose a model for the tectonic and stratigraphic evolution for the Manglares Basin and its oceanic basement. This model shows that (1) unconformity U5 between units F and E marks a tectonic phase that may correlate with the accretion of the oceanic basement of the Manglares Basin to the Northern Andes, possibly between the Late Cretaceous and Paleocene. (2) A marked change in seismic facies between Units E and D, associated with major tectonic unconformity U4 is compatible with the Incaic compressive phase that affected the Andes during the Late Eocene-Early Oligocene. (3) This tectonic phase likely peaked during the Latest Oligocene-Earliest Miocene (U3) and later during the Middle Miocene (U2). (4) The regional Middle Miocene erosion period (U2) marked a change in the tectono-sedimentary evolution of the forearc basin. Compressive deformation ceased in the southern margin segment, which underwent long-term basin subsidence, while compression and uplift increased in the central and northern segments

Coeval subduction erosion and underplating associated with a crustal splay fault at the Ecuador-Colombia convergent margin

International audienc

Influence of increasing convergence obliquity and shallow slab geometry onto tectonic deformation and seismogenic behavior along the Northern Lesser Antilles zone

International audienceIn subduction zones, the 3D geometry of the plate interface is one of the key parameters that controls margin tectonic deformation, interplate coupling and seismogenic behavior. The North American plate subducts beneath the convex Northern Lesser Antilles margin. This convergent plate boundary, with a northward increasing convergence obliquity, turns into a sinistral strike-slip limit at the northwestern end of the system. This geodynamic context suggests a complex slab geometry, which has never been imaged before. Moreover, the seismic activity and particularly the number of events with thrust focal mechanism compatible with subduction earthquakes, increases northward from the Barbuda–Anguilla segment to the Anguilla–Virgin Islands segment. One of the major questions in this area is thus to analyze the influence of the increasing convergence obliquity and the slab geometry onto tectonic deformation and seismogenic behavior of the subduction zone. Based on wide-angle and multichannel reflection seismic data acquired during the Antithesis cruises (2013–2016), we decipher the deep structure of this subduction zone. Velocity models derived from wide-angle data acquired across the Anegada Passage are consistent with the presence of a crust of oceanic affinity thickened by hotspot magmatism and probably affected by the Upper Cretaceous–Eocene arc magmatism forming the ‘Great Arc of the Caribbean’. The slab is shallower beneath the Anguilla–Virgin Islands margin segment than beneath the Anguilla–Barbuda segment which is likely to be directly related to the convex geometry of the upper plate. This shallower slab is located under the forearc where earthquakes and partitioning deformations increase locally. Thus, the shallowing slab might result in local greater interplate coupling and basal friction favoring seismic activity and tectonic partitioning beneath the Virgin Islands platform