Modern imaging and dissemination methods enable morphologists to share complex, three-dimensional (3D) data in ways not previously possible. Here we present a 3D interactive model of the jaw ...musculature of the American Alligator (Alligator mississippiensis). Alligator and crocodylian jaw musculature is notoriously challenging to inspect and interpret because of the derived nature of the feeding apparatus. Using Iodine-contrast enhanced microCT imaging, a segmented model of jaw muscles, trigeminal nerve, brain and skull are presented as a cross-sectional atlas and 3D, interactive pdf of the rendered model. Modern 3D dissemination methods like this 3D Alligator hold great potential for morphologists to share anatomical information to scientists, educators, and the public in an easily downloadable format.
Morphologists have historically had to rely on destructive procedures to visualize the three‐dimensional (3‐D) anatomy of animals. More recently, however, non‐destructive techniques have come to the ...forefront. These include X‐ray computed tomography (CT), which has been used most commonly to examine the mineralized, hard‐tissue anatomy of living and fossil metazoans. One relatively new and potentially transformative aspect of current CT‐based research is the use of chemical agents to render visible, and differentiate between, soft‐tissue structures in X‐ray images. Specifically, iodine has emerged as one of the most widely used of these contrast agents among animal morphologists due to its ease of handling, cost effectiveness, and differential affinities for major types of soft tissues. The rapid adoption of iodine‐based contrast agents has resulted in a proliferation of distinct specimen preparations and scanning parameter choices, as well as an increasing variety of imaging hardware and software preferences. Here we provide a critical review of the recent contributions to iodine‐based, contrast‐enhanced CT research to enable researchers just beginning to employ contrast enhancement to make sense of this complex new landscape of methodologies. We provide a detailed summary of recent case studies, assess factors that govern success at each step of the specimen storage, preparation, and imaging processes, and make recommendations for standardizing both techniques and reporting practices. Finally, we discuss potential cutting‐edge applications of diffusible iodine‐based contrast‐enhanced computed tomography (diceCT) and the issues that must still be overcome to facilitate the broader adoption of diceCT going forward.
The cartilago transiliens is a fibrocartilaginous structure within the jaw muscles of crocodylians. The cartilago transiliens slides between the pterygoid buttress and coronoid region of the lower ...jaw and connects two muscles historically identified as m. pseudotemporalis superficialis and m. intramandibularis. However, the position of cartilago transiliens, and its anatomical similarities to tendon organs suggest the structure may be a sesamoid linking a single muscle. Incompressible sesamoids often form inside tendons that wrap around bone. However, such structures rarely ossify in reptiles and have thus far received scant attention. We tested the hypothesis that the cartilago transiliens is a sesamoid developed within in one muscle by investigating its structure in an ontogenetic series of Alligator mississippiensis using dissection, 3D imaging, and polarizing and standard light microscopy. In all animals studied, the cartilago transiliens receives collagen fibers and tendon insertions from its two main muscular attachments. However, whereas collagen fibers were continuous within the cartilaginous nodule of younger animals, such continuity decreased in older animals, where the fibrocartilaginous core grew to displace the fibrous region. Whereas several neighboring muscles attached to the fibrous capsule in older individuals, only two muscles had significant contributions to the structure in young animals. Our results indicate that the cartilago transiliens is likely a sesamoid formed within a single muscle (i.e., m. pseudotemporalis superficialis) as it wraps around the pterygoid buttress. This tendon organ is ubiquitous among fossil crocodyliforms indicating it is a relatively ancient, conserved structure associated with the development of the large pterygoid flanges in this clade. Finally, these findings indicate that similar tendon organs exist among potentially homologous muscle groups in birds and turtles, thus impacting inferences of jaw muscle homology and evolution in sauropsids in general.
Extant archosaurs exhibit highly divergent articular soft tissue anatomies between avian and crocodilian lineages. However, the general lack of understanding of the dynamic interactions among ...archosaur joint soft tissues has hampered further inferences about the function and evolution of these joints. Here we use contrast‐enhanced computed tomography to generate 3D surface models of the pelvis, femora, and hip joint soft tissues in an extant archosaur, the American alligator. The hip joints were then animated using marker‐based X‐Ray Reconstruction of Moving Morphology (XROMM) to visualize soft tissue articulation during forward terrestrial locomotion. We found that the anatomical femoral head of the alligator travels beyond the cranial extent of the bony acetabulum and does not act as a central pivot, as has been suggested for some extinct archosaurs. Additionally, the fibrocartilaginous surfaces of the alligator’s antitrochanter and femoral neck remain engaged during hip flexion and extension, similar to the articulation between homologous structures in birds. Moreover, the femoral insertion of the ligamentum capitis moves dorsoventrally against the membrane‐bound portion of the medial acetabular wall, suggesting that the inner acetabular foramen constrains the excursion of this ligament as it undergoes cyclical stretching during the step cycle. Finally, the articular surface of the femoral cartilage model interpenetrates with those of the acetabular labrum and antitrochanter menisci; we interpret such interpenetration as evidence of compressive deformation of the labrum and of sliding movement of the menisci. Our data illustrate the utility of XROMM for studying in vivo articular soft tissue interactions. These results also allow us to propose functional hypotheses for crocodilian hip joint soft tissues, expanding our knowledge of vertebrate connective tissue biology and the role of joint soft tissues in locomotor behavior.
We assessed the kinematic relationship of hip joint soft tissues in the American alligator during the high walk using XROMM and DiceCT techniques. Repeated kinematic patterns allow interpretation of a non‐pivoting femoral head, engagement between the femoral neck and antitrochanter, ligament movement, as well as labrum compression. These results allow us to propose functional hypotheses of crocodylian joint tissues and expand our knowledge on the role of vertebrate joint tissues.
Background We investigated whether androgen deprivation therapy (ADT) use is associated with an increased risk of death from cardiovascular causes in patients treated for localized prostate cancer. ...Methods From the Cancer of the Prostate Strategic Urologic Research Endeavor database, data on 3262 patients treated with radical prostatectomy and 1630 patients treated with external beam radiation therapy, brachytherapy, or cryotherapy for localized prostate cancer were included in this analysis. Competing risks regression analyses were performed to assess whether use of ADT was associated with a shorter time to death from cardiovascular causes after controlling for age (as a continuous variable) and the presence of baseline cardiovascular disease risk factors. All tests for statistical significance were two-sided. Results The median follow-up time was 3.8 years (range = 0.1–11.3 years). Among the 1015 patients who received ADT, the median duration of ADT use was 4.1 months (range = 1.0–32.9 months). In a competing risks regression analysis that controlled for age and risk factors for cardiovascular disease, both ADT use (adjusted hazard ratio HR = 2.6; 95% confidence interval CI = 1.4 to 4.7; P = .002) and age (adjusted HR = 1.07; 95% CI = 1.02 to 1.1; P = .003) were associated with statistically significantly increased risks of death from cardiovascular causes in patients treated with radical prostatectomy. Among patients 65 years or older treated with radical prostatectomy, the 5-year cumulative incidence of cardiovascular death was 5.5% (95% CI = 1.2% to 9.8%) in those who received ADT and 2.0% (95% CI = 1.1% to 3.0%) in those who did not. Among patients 65 years or older treated with external beam radiation therapy, brachytherapy, or cryotherapy, ADT use was associated with a higher cumulative incidence of death from cardiovascular causes, but the difference did not reach statistical significance. Conclusions The use of ADT appears to be associated with an increased risk of death from cardiovascular causes in patients undergoing radical prostatectomy for localized prostate cancer.
Chemoradiation for anal cancer yields effective tumor control, but is associated with significant acute toxicity. We report our multi-institutional experience using dose-painted IMRT (DP-IMRT).
...Between August 2005 and May 2009, 43 patients were treated with DP-IMRT and concurrent chemotherapy for biopsy-proven, squamous cell carcinoma of the anal canal at two academic medical centers. DP-IMRT was prescribed as follows: T2N0: 42 Gy, 1.5 Gy/fraction (fx) to elective nodal planning target volume (PTV) and 50.4 Gy, 1.8 Gy/fx to anal tumor PTV; T3-4N0-3: 45 Gy, 1.5 Gy/fx to elective nodal PTV, and 54 Gy, 1.8 Gy/fx to the anal tumor and metastatic nodal PTV >3 cm with 50.4 Gy, 1.68 Gy/fx to nodal PTVs ≤ 3 cm in size. Acute and late toxicity was reported by the treating physician. Actuarial analysis was performed using the Kaplan-Meier method.
Median age was 58 years; 67% female; 16% Stage I, 37% II; 42% III; 5% IV. Fourteen patients were immunocompromised: 21% HIV-positive and 12% on chronic immunosuppression. Median follow-up was 24 months (range, 0.6-43.5 months). Sixty percent completed chemoradiation without treatment interruption; median duration of treatment interruption was 2 days (range, 2-24 days). Acute Grade 3+ toxicity included: hematologic 51%, dermatologic 10%, gastrointestinal 7%, and genitourinary 7%. Two-year local control, overall survival, colostomy-free survival, and metastasis-free survival were 95%, 94%, 90%, and 92%, respectively.
Dose-painted IMRT appears effective and well-tolerated as part of a chemoradiation therapy regimen for the treatment of anal canal cancer.
More than one way to be a giant Tsai, Henry P.; Middleton, Kevin M.; Hutchinson, John R. ...
Evolution,
08/2020, Letnik:
74, Številka:
8
Journal Article
Recenzirano
Odprti dostop
Saurischian dinosaurs evolved seven orders of magnitude in body mass, as well as a wide diversity of hip joint morphology and locomotor postures. The very largest saurischians possess incongruent ...bony hip joints, suggesting that large volumes of soft tissues mediated hip articulation. To understand the evolutionary trends and functional relationships between body size and hip anatomy of saurischians, we tested the relationships among discrete and continuous morphological characters using phylogenetically corrected regression. Giant theropods and sauropods convergently evolved highly cartilaginous hip joints by reducing supraacetabular ossifications, a condition unlike that in early dinosauromorphs. However, transitions in femoral and acetabular soft tissues indicate that large sauropods and theropods built their hip joints in fundamentally different ways. In sauropods, the femoral head possesses irregularly rugose subchondral surfaces for thick hyaline cartilage. Hip articulation was achieved primarily using the highly cartilaginous femoral head and the supraacetabular labrum on the acetabular ceiling. In contrast, theropods covered their femoral head and neck with thinner hyaline cartilage and maintained extensive articulation between the fibrocartilaginous femoral neck and the antitrochanter. These findings suggest that the hip joints of giant sauropods were built to sustain large compressive loads, whereas those of giant theropods experienced compression and shear forces.
Theropods are obligate bipedal dinosaurs that appeared 230 Ma and are still extant as birds. Their history is characterized by extreme variations in body mass, with gigantism evolving convergently ...between many lineages. However, no quantification of hindlimb functional morphology has shown whether these body mass increases led to similar specializations between distinct lineages. Here we studied femoral shape variation across 41 species of theropods (n = 68 specimens) using a high-density 3D geometric morphometric approach. We demonstrated that the heaviest theropods evolved wider epiphyses and a more distally located fourth trochanter, as previously demonstrated in early archosaurs, along with an upturned femoral head and a mediodistal crest that extended proximally along the shaft. Phylogenetically informed analyses highlighted that these traits evolved convergently within six major theropod lineages, regardless of their maximum body mass. Conversely, the most gracile femora were distinct from the rest of the dataset, which we interpret as a femoral specialization to “miniaturization” evolving close to Avialae (bird lineage). Our results support a gradual evolution of known “avian” features, such as the fusion between lesser and greater trochanters and a reduction of the epiphyseal offset, independent from body mass variations, which may relate to a more “avian” type of locomotion (more knee than hip driven). The distinction between body mass variations and a more “avian” locomotion is represented by a decoupling in the mediodistal crest morphology, whose biomechanical nature should be studied to better understand the importance of its functional role in gigantism, miniaturization, and higher parasagittal abilities.
Enterovirus (EV) 71 may cause severe neurological illness in the pediatric population. The present study aimed to compare the detection rates of reverse transcription-polymerase chain reaction ...(RT-PCR) with pan-EV/EV71 type- specific primers and virus culture (VC) for the identification of EV and EV71 using specimens from multiple sites. In total, specimens from throat/rectal swabs, cerebrospinal fluid (CSF), and blood from 66 patients diagnosed with EV encephalomyelitis were subjected to both RT-PCR and VC for detecting the presence of pan-EV and EV71. The results revealed that the positive RT-PCR rate was higher in throat swabs (60.6%) and rectum swabs (50.0%) than in CSF (16.7%) and blood (15.6%). The same trend was also observed in case of VC: throat swabs (22.7%), rectum swabs (10.6%), and blood (3.0%). The detection rate of EV encephalomyelitis by RT-PCR was 90.9% for all samples, 63.6% of which were subtyped as EV71. The detection rates of RT-PCR were superior to those of VC, and identification using specimens from throat/rectal swabs yielded higher positive results. These findings may help physicians to identify the etiologies at an early stage during EV71 epidemics and to make emergent medical decisions for minimizing patient morbidity and mortality.
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