We describe the bony and cartilaginous structures of five fetal skulls of Stenella attenuata (pantropical spotted dolphin) specimens. The specimens represent early fetal life as suggested by the presence of rostral tactile hairs and the beginnings of skin pigmentation. These specimens exhibit the developmental order of ossification of the intramembranous and endochondral elements of the cranium as well as the functional and morphological development of specific cetacean anatomical adaptations. Detailed observations are presented on telescoping, nasal anatomy, and middle ear anatomy. The development of the middle ear ossicles, ectotympanic bone, and median nasal cartilage is of interest because in the adult these structures are morphologically different from those in land mammals. We follow specific cetacean morphological characteristics through fetal development to provide insight into the form and function of the cetacean body plan. Combining these data with fossil evidence, it is possible to overlie ontogenetic patterns and discern evolutionary patterns of the cetacean skull. Anat Rec, 294:1743Rec, 294: -1756Rec, 294: , 2011. V V C 2011 Wiley-Liss, Inc.Key words: cranial development; Stenella attenuata; telescoping; middle ear; CetaceaThe development of the Cetacea skull was studied in embryos (de Burlet, 1913a(de Burlet, , 1913b(de Burlet, , 1914a(de Burlet, , 1914bSchreiber, 1916;Honigmann, 1917;Rauschmann et al., 2006;Thewissen and Heyning, 2007) and fetuses (Schulte, 1916;Ridewood, 1923;Eales, 1950). Cetacean research focused on specific biological systems to understand differences within Mammalia. Comtesse-Weidner (2007), Miller (1923 and Kellogg (1928aKellogg ( , 1928b) studied morphological elements including telescoping. Oelschl-ä ger and Buhl (1985), Klima and van Bree (1990), and Klima (1995 studied nasal anatomy and development. Oelschlä ger (1986, 1990), Solntseva (1990, 2002), and Kinkel et al. (2001 concentrated on hearing reception and sound emission while Mead and Fordyce (2009) focused on general skull anatomy. Although comparative embryological studies on cetaceans were rare, developmental studies were mostly nonexistent. Such studies (e.g., Thewissen et al., 2006, Armfield et al., in press) allow for a deeper understanding of the ontogenetic constraints on the evolution of the cetacean body plan.Habitat changes alter adaptations for specific cetacean body plans. These modifications include those of anatomical function and body plan from land mammals to fully aquatic, air breathing marine mammals. Our study focuses on anatomical structures of five Stenella attenuata (pantropical spotted dolphin) fetuses. Here we describe bony and cartilaginous structures of the
Inflammatory bowel disease (IBD) is characterized by chronic inflammation of the intestinal tract and is associated with decreased bone mineral density. IBD patients are at higher risk of osteopenia, osteoporosis and fracture compared to non-IBD patients. The impact of IBD on the performance of orthopedic implants has not been well studied. We hypothesized that a history of IBD at the time of primary total hip arthroplasty (THA) would increase the risk of subsequent failure as assessed by revision surgery. A retrospective implant survival analysis was completed using the Swedish Hip Arthroplasty Registry and the Sweden National Patient Register. A total of 150,073 patients undergoing THA for osteoarthritis within an 18-year period were included in the study. THA patients with (n = 2,604) and without (n = 147,469) a history of IBD at the time of THA were compared with primary revision as the main endpoint and adjusted using sex, age category and comorbidity (Elixhauser scores) as covariates. We found that patients with a history of IBD had a relatively higher risk of revision surgery for septic causes while the non-IBD patients had a relatively higher risk of revision for aseptic causes (p = 0.004). Our findings suggest there may be an association between gut health and THA performance.
Articular cartilage lines the load-bearing surfaces of long bones and undergoes compositional and structural degeneration during osteoarthritis progression. Contrast enhanced microcomputed tomography (μCT) is being applied to a variety of preclinical models, including the mouse, to map structural and compositional properties in 3-D. The thinness (~30–50 μm) and high cellularity of mouse articular cartilage presents a significant imaging challenge. Our group previously showed that mouse articular cartilage and proteoglycan (PG) content can be assessed by μCT with the ioxagalate-based contrast agent Hexabrix, but the voxel size used (6 μm) was deemed to be barely adequate. The objective of the present study is to assess the utility of a novel contrast agent, CA4+, to quantify mouse articular cartilage morphology and composition with high resolution μCT imaging (3 μm voxels) and to compare the sensitivity of CA4+ and Hexabrix to detect between-group differences. While both contrast agents are iodine-based, Hexabrix is anionic and CA4+ is cationic so they interact differently with negatively charged PGs. With CA4+, a strong correlation was found between non-calcified articular cartilage thickness measurements made with histology and μCT (R2 = 0.72, p < 0.001). Cartilage degeneration – as assessed by loss in volume, thickness and PG content – was observed in 34-week old mice when compared to both 7- and 12-week old mice. High measurement precision was observed with CA4+, with the coefficient of variation after repositioning and re-imaging samples equaling 2.8%, 4.5%, 7.4% and 5.9% for attenuation, thickness, volume, and PG content, respectively. Use of CA4+ allowed increased sensitivity for assessing PG content compared to Hexabrix, but had no advantage for measurement of cartilage thickness or volume. This improvement in imaging should prove useful in preclinical studies of cartilage degeneration and regeneration.
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