Axial Skeleton Research Articles

Single-cell RNA-sequencing analysis of immune and mesenchymal cell crosstalk in the developing enthesis

Autoimmunity underlies many painful disorders, such as enthesopathies, which localize to the enthesis. From infiltration of the synovium and axial skeleton by B cells, to disturbances in the ratio of M1/M2 enthesis macrophages, to CD8 + T cell mediated inflammation, autoimmune dysregulation is becoming increasingly well characterized in enthesopathies. Tissue resident B cells, macrophages, neutrophils, and T cells have also been localized in healthy human entheses. However, the potential developmental origins, presence, and role of immune cells (ICs) in enthesis development is not known. Here, we use single-cell RNA-sequencing analysis to describe IC subtypes present in the enthesis before, during, and after mineralization, and to infer regulatory interactions between ICs and mesenchymal cells (MCs). We report the presence of nine phenotypically distinct IC subtypes, including B cells, macrophages, neutrophils, and T cells. We find that specific IC subtypes may promote MC-proliferation and differentiation, and that MCs may regulate IC phenotype and autoimmunity. Our findings suggest that bidirectional regulatory interactions between ICs and MCs may be important to enthesis mineralization, and suggest that progenitor MCs have a unique ability to limit autoimmunity during development.

Modeling of Skeletal Development and Diseases Using Human Pluripotent Stem Cells.

Human skeletal elements are formed from distinct origins at distinct positions of the embryo. For example, the neural crest produces the facial bones, the paraxial mesoderm produces the axial skeleton, and the lateral plate mesoderm produces the appendicular skeleton. During skeletal development, different combinations of signaling pathways are coordinated from distinct origins during the sequential developmental stages. Models for human skeletal development have been established using human pluripotent stem cells (hPSCs) and by exploiting our understanding of skeletal development. Stepwise protocols for generating skeletal cells from different origins have been designed to mimic developmental trails. Recently, organoid methods have allowed the multicellular organization of skeletal cell types to recapitulate complicated skeletal development and metabolism. Similarly, several genetic diseases of the skeleton have been modeled using patient-derived induced pluripotent stem cells and genome-editing technologies. Model-based drug screening is a powerful tool for identifying drug candidates. This review briefly summarizes our current understanding of the embryonic development of skeletal tissues and introduces the current state-of-the-art hPSC methods for recapitulating skeletal development, metabolism, and diseases. We also discuss the current limitations and future perspectives for applications of the hPSC-based modeling system in precision medicine in this research field.

Primitive Myxoid Mesenchymal Tumor of Infancy: A Lost Battle

ABSTRACT Primitive myxoid mesenchymal tumor of infancy (PMMTI) is a low to intermediate-grade, poorly differentiated myofibroblastic tumor and is characterized by its tendency to recur locally. It commonly occurs in the 1st year of life and is predominantly seen in the axial skeleton and rarely in the retroperitoneum. We report one such case of PMMTI, which is the second case reported in English literature.

Inflammatory arthropathies: Perspectives from a Portuguese male individual (1574–1834 CE)

AbstractArthropathies are common in past populations and can be categorized into two groups: those with predominant bone production (e.g., osteoarthritis) and those with significant bone loss (e.g., erosive arthropathies). The former is frequent in the archaeological record, whereas the latter are uncommon. We present a Post‐Medieval male individual, recovered in the Convent of the Holy Spirit (Loures, Portugal), with multiple articular and entheseal bone changes, particularly extensive periarticular, marginal, and subchondral erosive processes, often exposing trabecular bone. Proliferative lesions and extensive ankylosis are also observed in the synovial joints. These pathological changes affect both the axial and peripheral skeleton in a polyarticular, bilateral, and asymmetric pattern. Given that the appendicular skeleton, particularly the hands and feet, are the most affected areas, the most probable diagnosis is a peripheral spondyloarthropathy such as psoriatic arthritis or reactive arthritis. This case study is the first archaeological instance of psoriatic arthritis or reactive arthritis described in Portugal, highlighting the importance of a differential diagnosis and the need for reflection when pathological changes characteristics overlap, advocating for a broader diagnostic approach.

Marked osteopenia as a CT feature of confirmed multiple myeloma in a dog

AbstractA 6‐year‐old, female, spayed Airedale terrier, presented with a 7‐day history of right pelvic limb lameness and a 2‐day history of gingival bleeding and melaena. A mild bi‐cytopenia had been reported 2 years before during a regular check‐up, and this was still present a week before referral. A computed tomographic study of the thorax and abdomen showed marked osteopenia and multifocal coalescent areas of geographic osteolysis affecting predominantly the axial skeleton with concurrent pathological rib fractures. Bone marrow cytology and histopathology were compatible with multiple myeloma given an increased numbers of plasma cells (>70%). To the authors’ knowledge, this is the first reported case of marked generalised osteopenia detected as a computed tomography imaging feature of multiple myeloma.

Computed tomography of the equine caudal spine and pelvis. Pathological findings in 56 clinical cases (2018-2023).

Computed tomography (CT) of the axial skeleton is increasing across many equine hospitals. CT of the pelvis and caudal spine in a large group of clinical cases has not been reported previously. To describe the pathological lesions identified in the caudal spine/pelvis in horses and ponies undergoing CT spine of this region. A retrospective case series. Horses with CT imaging of the caudal spine/pelvis were included. Horses aged under 6 months and those with CT examinations performed post-mortem were excluded. Fifty-six horses met the inclusion criteria. Ages ranged from 8 months to 20 years and bodyweights from 85 to 680 kg (mean 488 kg). Horses presented predominantly for lameness (30/56) and poor performance (18/56). Osseous pathology was identified in 41/56 horses; including osteoarthritis of the sacroiliac joint(s) (n: 28), pathology of the intervertebral disc joint(s) (n: 12), pelvic fractures (n: 9), osteoarthritis of the coxofemoral joint(s) (n: 8), ventral spondylosis (n: 6), acetabular rim fracture (n: 2), dislocation of coxofemoral joint(s) (n: 2), and dorsal dermal sinus of the sacrum (n: 1). The relationship between CT imaging findings and clinical signs in horses remains unclear. Further work is required to describe the relationship between congenital, developmental, and acquired changes in the caudal spine and pelvis, and clinical signs. CT of the caudal spine and pelvis can be utilised in horses and ponies for diagnosing a range of clinical disorders that may be causing 'lumbosacroiliac pain', poor performance, hindlimb lameness, and stiffness. The pathologies we observed were diverse and many patients had multiple lesions.

The development of the bone system of young Bestuzhev breed and its crossbreeds with simmentals

Relevance. As a result of morphological studies, materials were obtained characterizing the effect of genotype and castration of young cattle and the development of the bone system in the postnatal period of ontogenesis.Methodology. For the purpose of conducting the experiment, groups of experimental young animals were selected:Results. The influence of the genotype and castration of young cattle on the absolute weight and length of individual parts and the entire skeleton of gobies and castrated gobies of the Bestuzhev breed and its first-generation crossbreeds with simmentals was established. The advantage of crossbred bulls of the ½ Bestuzhevskaya × ½ simmental group II in terms of the absolute weight of both the axial and peripheral skeleton over purebred and crossbred bulls and castrated bulls of the Bestuzhevskaya breed, crossbred castrated bulls has been established. For the entire mass of the carcass skeleton, this superiority was, respectively, 12 g (2.4%), 6616 g (14.7%) and 5553 (12.0%). Similar intergroup differences were found in the length of individual parts and the entire skeleton of the carcass.

High dose chemotherapy with autologous stem cell rescue in children and young adults with high-risk Ewing sarcoma: A single institute experience in Taiwan.

A combination treatment of surgery, chemotherapy, and radiotherapy can improve the survivals of pediatric patients with Ewing sarcoma (ES). However, prognosis remains poor for patients with metastatic disease at diagnosis or recurrence. Other high-risk (HR) features include large tumor burden, tumors of the axial skeleton and poor histologic response. Several studies have documented high dose chemotherapy with autologous stem cell rescue (HDC-ASCR) to be effective in such patients. In this retrospective study, we present the results of HDC-ASCR for high-risk Ewing sarcoma in children and young adults in a single institute. From March 2004 to March 2021, patients with ES, Ewing-like sarcoma, or round cell sarcoma received HDC-ASCR as part of treatment were included. The patients' characteristics, disease status, stem cell dose, engraftment status, post-transplant complications, and outcomes were analyzed. Twenty patients receiving HDC-ASCR at complete response (n = 6), partial response (n = 13), and stable disease (n = 1) were enrolled. The male to female ratio was 11:9. Median age at diagnosis and transplant was 15.6 years old (range: 3.3-28.9) and 16.2 (range: 4.2-29.9), respectively. The conditioning regimens included ifosfamide-based in two and melphalan-based in 19. All patients achieved successful engraftment without tansplant-related mortality. The 5-year progression-free and overall survival (OS) rate were 35% and 54.5%, respectively. The causes of death (n = 8) were all contributed to disease progression. Patients in the complete response group or with localized HRES exhibited a higher 5-year OS (p = 0.047 and 0.05, respectively). Compared to the historical cohort without HDC-ASCR as part of primary treatment, the current cohort had a significantly better 5-year OS (p = 0.018). HDC-ASCR seems promising as an alternative treatment for HRES in improving OS in this retrospective study with limited case number.

Prominent Bone Marrow Infiltration in the Appendicular Skeleton in a B-cell Acute Lymphoblastic Leukemia Patient Demonstrated by FDG PET-MRI.

Leukemia spread in the bone marrow typically is greater in the axial skeleton than in the appendicular skeleton. We report an unusual pattern of FDG-avid bone marrow infiltration that is more prominent in the appendicular skeleton than the axial skeleton in a pediatric patient with B-cell acute lymphoblastic leukemia.

Calprotectin as a marker of disease activity in spondyloarthritis

Introduction: Spondyloarthritis is a group of arthritic diseases that classically manifest as inflammation of the sacroiliac and limb joints, as well as the axial skeleton. Microscopic bowel inflammation is identifiable in over 50% of these patients. Calprotectin measured in the serum and stool is an emerging surrogate marker of disease activity and/or bowel inflammation in spondyloarthritis. Objective: This article aims to review published literature to determine the accuracy of serum and faecal calprotectin levels for use in monitoring bowel inflammation and spondyloarthritis disease activity. Methods: Boolean operator strategy was used to search two databases (Embase and PubMed) and 52 relevant articles were identified. Duplicate results were eliminated, inclusion and exclusion criteria were applied. Results: Ten studies met the inclusion criteria and were summarized and analyzed. The EBL Validity questionnaire was applied to determine study quality. All research articles found calprotectin to be elevated in spondyloarthritis patients when compared to controls. Faecal calprotectin was superior in detecting disease activity and correlated with disease activity questionnaires, radiology and endoscopy results. Only one study assessed the effect of treatment on calprotectin and its correlation to bowel inflammation. Conclusion: Faecal calprotectin shows promise as a surrogate marker for disease activity and bowel inflammation in spondyloarthritis. Future studies should focus on the effect of treatment on faecal calprotectin and whether some treatments are better at preventing the progression of bowel inflammation in addition to treating spondyloarthritis. Supplementary investigations are needed to identify whether faecal calprotectin is useful as a marker of disease activity in response to treatment.

A Systems-Level Analysis of 2-[18F]FDG PET in Pigs Reveals Complex Skeletal Metabolism Networks in vivo which are altered with Osteomyelitis

Our understanding of complex tissue interactions at a systems level remains rudimentary, limiting our ability to dissect mechanisms underlying diseases and develop novel therapeutics. Skeletal research has focused on the pathogenicity of obesity and diabetes mellitus on the skeleton; however, it has been recently revealed that the skeleton is not merely an endocrine target but also a secretory organ, modulating systemic energy homeostasis1,2. We recently discovered that different bones within the murine skeleton have a unique glucose metabolism and form a complex metabolic network3. Thus, we hypothesised that different bones within the porcine skeleton would have unique molecular signatures and form a distinct metabolic network, and these networks would be altered by osteomyelitis, an inflammatory condition of the bone. Five healthy mini and three Danish Landrace-Yorkshire pigs (inoculated with S. aureus to induce osteomyelitis) underwent static 2-[18F]FDG PET/CT and were analysed to measure bone and bone marrow adipose tissue (BMAT) glucose metabolism. Analyze was used for image analysis and processing. Bone and bone marrow volumes of interest were segmented in CT images using Hounsfield Unit (HU) > 300 (bone) and HU -200 to 115 (BMAT; Fig1). PET images were used to extract average standard uptake values. Network analysis was performed using Graphia. Osteomyelitis pigs had a lower bone density and increased BMAT volume compared to healthy controls. There was an increased incorporation of 2-[18F]FDG into the bone and BMAT of osteomyelitis pigs. Similar to what has previously been observed in the mouse3 and human4, there was an increased incorporation of 2-[18F]FDG in the axial skeleton compared to the appendicular skeleton. Network analysis indicated a shift in bone metabolic profiles between healthy and osteomyelitis pigs. Please click on the 'PDF' for the full abstract!

7949 Unraveling a Unique Presentation of Paget’s Disease of Bone

Abstract Disclosure: S. Puri: None. L. Bovee: None. R. Narla: None. Background: Paget's Disease of Bone (PDB) is a disorder characterized by rapid bone destruction and repair, which results in distortion of bone architecture. PDB occurs most commonly in adults over 55 and of European descent. PDB presents with both lytic and sclerotic lesions, predominantly in the axial skeleton. Serum alkaline phosphatase (ALP) levels and bone turnover markers (BTMs) are typically elevated in PDB. Clinical Case: A 53-year-old African-American woman with a history of breast cancer, PTSD, depression, and obesity (BMI 37) presented with worsening back pain over the past six months. Her pain would start at the center of her back and radiate to her left lower extremity. She endorsed rapid weight loss and night sweats and had lumbar bony tenderness on exam, prompting a spinal MRI. Spinal MRI was significant for diffuse sclerosis of the L3 vertebral body only. The radiology report provided a broad differential for this finding, including metastases, lymphoma, infection, PDB, and hemangioma. Due to progression of the patient’s back pain and concern for possible malignancy, a whole-body SPECT was completed which showed isolated tracer uptake into the L3 vertebral body extending into the pedicles and spinous process. Similar findings were noted on bone scans dating back to 2001. Per the radiology report, the presence of sclerosis with minimal expansion is most suggestive of PDB. Endocrinology was consulted for guidance on treatment and surveillance imaging for this patient. The endocrinology team discussed the case with radiology, who confirmed that the patient’s imaging findings had classic features of PDB. Bone specific ALP (B-ALP) and procollagen type 1 amino-terminal propeptide (P1NP) as bone turnover markers (BTMs) were within normal limits. A DEXA scan is pending to evaluate for concurrent osteoporosis. Clinical Lessons: PDB was favored as the most likely diagnosis primarily due to the sclerotic appearance of the patient’s vertebral lesion on imaging, radicular symptoms, and exam finding of bony point tenderness. Other diagnoses, such as metastatic disease, were considered and were thought to be unlikely given that the vertebral lesion is monostotic and stable. This case highlights the necessity of carefully evaluating radiographic findings and clinical history in the diagnosis of PDB. In this case, the patient was from a demographic group unlikely to have PDB and, unexpectedly, did not have elevated BTMs. It is important to consider PDB on the differential diagnosis in cases such as this because PDB can present in myriad ways and in a variety of patient populations. Presentation: 6/2/2024

6539 Hungry Bone Syndrome & Osteoblastic Metastasis In The Setting Of Prostate Cancer : A Rare Cause Of Hypocalcemia

Abstract Disclosure: B. Sharma: None. M. Khan: None. A. Rao: None. P. Guido: None. Background: Hungry bone syndrome (HBS) is due to excessive calcium and phosphorus sequestration in the bone, manifesting as hypocalcemia and hypophosphatemia.It is most commonly seen as a postoperative complication of parathyroidectomy.Advanced prostate cancer with osseous metastasis has been previously described as is a rare cause of HBS. Clinical Case: A 65 year old male was admitted to the hospital with acute congestive heart failure and severe hypocalcemia.He exhibited symptoms of muscle spasms and perioral paraesthesias. Physical exam was positive for Trousseau's sign.Initial tests were consistent with severe hypocalcemia (corrected non-ionized calcium 6.8 [8.8-10.2] mg/dL), low ionized calcium (0.58 [1.10-1.30] mmol/L). Three weeks prior to admission, corrected non-ionized calcium was 9.8 mg/mL. Other labs showed normal magnesium, normal phosphorus, elevated alkaline phosphatase (1044 [45-117] U/L), low Vitamin D (12 [>30] ng/mL ), elevated iPTH (567 [19-88] pg/mL) and low PTH-rp (9 [11-20] pg/mL]. His electrocardiogram showed regular rate and rhythm with Qtc prolongation (497 ms).He had a significant oncological history of prostate cancer and multiple myeloma in remission.He was previously treated with zoledronic acid, discontinued 1 year prior to admission, for reducing skeletal complications while being treated for multiple myeloma. He had a recent workup with medical oncology for recurrence of prostate cancer due to elevated Prostate-specific antigen (380 [<4.00] ng/mL).Computed tomography imaging showed diffuse osteoblastic metastatic disease in the axial skeleton, pelvis and proximal femur. During hospital admission hypocalcemia was persistent, likely also due to concurrent furosemide use, necessitating the administration of intravenous calcium infusion and use of cholecalciferol and calcitriol.He was discharged on calcium carbonate 4500 mg twice a day, cholecalciferol 50 000 units weekly for 12 weeks and calcitriol 2 mcg twice a day. Conclusion: Hypocalcemia in the setting of prostate cancer is most commonly due to the use of bisphosphonates or Receptor activator of nuclear factor kappa-B ligand (RANK-L) inhibitors. Hypocalcemia in this case was due to sequestration of calcium in the bone by osteoblastic metastasis. This case illustrates the importance of recognising osteoblastic metastasis as a differential in protracted and severe hypocalcemia in malignancy.High doses of calcium, vitamin D, and calcitriol replacement are often needed as the hypocalcemia is usually severe and refractory with some cases requiring prolonged IV calcium infusion.Treatment of the underlying cancer and bone metastases with chemotherapy has been shown to improve hypocalcemia and reduce the requirement of calcium and vitamin D supplementation.There is limited data to suggest if bisphosphonates can be safely used in these cases for prevention of skeletal related events. Presentation: 6/1/2024

6714 Bone And Radiologic Findings In Congenital Generalized Lipodystrophy: A Systematic Review

Abstract Disclosure: R.M. Tuska: None. M. Brush: None. A.A. Livinski: None. R.J. Brown: None. Congenital Generalized Lipodystrophy (CGL) is characterized by a near-total loss of subcutaneous adipose tissue, leading to severe metabolic and systemic comorbidities. CGL is most commonly caused by mutations in AGPAT2 (CGL1) and BSCL2 (CGL2) genes. Skeletal abnormalities such as diffuse sclerosis, lytic bone lesions, and high bone mineral density (BMD) have been recognized in many patients with CGL, but the radiologic and clinical features of these bone phenotypes remain ill-defined. The aim of this systematic review was to evaluate the bone manifestations and radiologic findings associated with CGL1 and CGL2. We searched 6 databases: CINAHL Plus, Embase, Global Index Medicus (WHO), PubMed, Scopus, and Web of Science: Core. We screened articles utilizing a dual reviewer process in Covidence. Included publications reported primary bone and radiologic findings in patients with CGL1 or CGL2. Exclusions comprised publications without full text, duplicate publications, those lacking bone measures, and review articles. Two reviewers extracted data using RedCap and assessed risk of bias. 270 records were screened and 37 records reporting 179 cases of CGL were included for data extraction. Among the 79 patients assessed for bone cysts, 49 (62%) exhibited lytic appearing lesions. Of these 49, 14 (29%) patients presented with symptomatic lesions, primarily manifesting as bone pain at the lesion site (n=6), or pathologic fracture at the lesion site (n=9). Bone biopsy (n=7) revealed thin trabeculae and extensive vascular proliferation at the lesion site. Bone marrow biopsies (n=2) and imaging (n=20) revealed normal hematopoietic marrow with a marked reduction in marrow fat. 12 patients underwent serial bone imaging revealing diffuse osteosclerosis and the absence of lytic lesions in early childhood. During adolescence, lytic lesions appeared and progressed throughout the proximal and distal ends of the long bones in the appendicular skeleton sparing the axial skeleton. Markers of bone turnover were within normal limits except for sclerostin, which was elevated in a cohort of 11 patients. High BMD (n= 65), advanced skeletal maturation (n= 49), diffuse osteosclerosis (n=30), scoliosis (n=8), pseudo-osteopoikilosis (n=6), coxa valga (n=5), enlarged epiphyses (n=7), and coarse trabeculae (n=8) were also reported. While leptin replacement therapy improved metabolic parameters in many patients, it did not reverse the high bone mineral density or significantly alter markers of bone turnover. Individuals with CGL exhibit a spectrum of skeletal abnormalities including lytic-appearing lesions, osteosclerosis, high bone mineral density, advanced skeletal maturation, and pseudo-osteopoikilosis. Further long-term follow-up is needed to comprehensively assess the progression of these lesions over the life course and to elucidate the mechanisms contributing to their development. Presentation: 6/2/2024

8802 A Rare Case Of Symptomatic Hypercalcemia In A Patient With Untreated Chronic Tophaceous Gout

Abstract Disclosure: S. Avula: None. A. Kumar: None. Z.J. Anderson: None. A. Chauhan: None. L.T. LaFave: None. Background: Hypercalcemia is a medical condition with abnormally high serum calcium levels. There are numerous mechanisms for the development of hypercalcemia, but gout is not well documented.Hypercalcemia attributed to Tophaceous gout is a rare phenomenon that is not well studied. Here we report a case of symptomatic hypercalcemia in a patient with a history of untreated tophaceous gout, leading to hypercalcemia and osteolytic lesions. Clinical Case: The patient is a 52-year-old male with a medical history of hypertension, rheumatoid arthritis, and tophaceous gout who immigrated from Tanzania. He presented with two weeks of abdominal pain that acutely worsened the morning of his presentation. He reported a 16-year history of tophaceous gout, for which he had been treated with allopurinol without success. On physical examination polyarticular subcutaneous nodules were present in the bilateral upper and lower extremities, primarily over the joints. There were similar lesions on the buttocks. Initial laboratory evaluation included a complete blood count which was notable for a hemoglobin of 10.3 g/dL (13.1 - 17.5 g/dL). His albumin was normal at 4 g/dl. (3.8 - 5.1 g/dl). Serum calcium was elevated at 12.9 mg/dL (8.8-10.0 mg/dL), with a serum ionized calcium level of 6.52 mg/dL(4.40-5.20 mg/dL). PTH was low at 15.8 pg/mL (16.0 - 65.0 pg/mL), and PTHrP was 2.9 pg/ml (<4.5 pg/ml). Uric acid level on admission was elevated to 11.4 mg/dL (3.4 - 7.0 mg/dL). 1-25 dihydroxy vitamin D elevated at 93.2 pg/mL (19.9 - 79.3 pg/mL). Computed tomography (CT) with intravenous contrast of the chest, abdomen, and pelvis was notable for axillary, pelvic, and inguinal lymphadenopathy concerning for lymphoproliferative or neoplastic processes. Biopsy of right inguinal node biopsy showed benign-appearing lymphoid tissue. Additional findings included multiple lobulated calcified hyperdense foci throughout the subcutaneous and muscular tissues of the buttocks with resorptive changes of the axial skeleton. Spectral CT reconstruction determined these to be uric acid deposits. Radiographs of his extremities were consistent with advanced gouty arthropathy. Infectious work-up was negative. Patient was given 3 liters of 0.9% sodium chloride. He received four doses of Calcitonin (4 units/kg) followed by one dose of Zoledronic acid 5 mg I.V. He was treated with Febuxostat, solumedrol and Azathioprine for his tophaceous gouty arthritis. Conclusion: Hypercalcemia is a commonly encountered yet a very important clinical condition. Parathyroid and malignant etiologies of hypercalcemia account for approximately 90% of cases of hypercalcemia. Gout as the inciting factor for developing hypercalcemia is a rarely documented phenomenon. This case highlights hypercalcemia as an unusual yet severe manifestation of untreated chronic gout and demonstrates the need for additional studies and reviews. Presentation: 6/2/2024

Radiographic, computed tomographic, and histologic characteristics of bone for clinically normal laying hens in a free-range housing system.

Laying hens are increasingly being kept in backyard flocks and considered family pets; however, diagnostic imaging characteristics of bone for clinically normal backyard hens are currently limited. This prospective, descriptive study was to describe radiographic, computed tomographic, and histologic characteristics of bone for a group of clinically normal laying hens housed in conditions comparable to those of backyard flocks. Sixteen 60-week-old Lohmann Brown laying hens were included. Hens were housed in a free-range unit with outdoor access at a university research and teaching farm. Hens were defined as clinically normal by the farm manager and a veterinary researcher in laying hen behavior and welfare. Findings from the horizontal beam, left lateral, sternal radiographs (n=16), postmortem, and whole-body CT scans (n=4) were recorded by a veterinary radiologist and a research technician. Histologic findings for sternal, femoral, and tibiotarsal bone samples (n=5) were recorded by a veterinary pathologist. The most frequent radiographic findings for the sternal carina (keel bone) were smoothly marginated concave deviations of the ventral margin and caudal section fractures. Multiple punctate mineral opacities (PMOs) were present in radiographs and CT images for all hens and were involved in the sternal carina and multiple other bones in the axial and appendicular skeleton. No bone abnormalities were identified in any histologic sections where PMOs were radiographically detected. Authors propose that PMOs are normal radiographic and CT findings in the bones of mature, laying hens and may represent temporary calcium reservoirs formed during osteoclastic activities.

Conservation of rib skeleton regionalization in the homoplastic evolution of the snake-like body form in squamates.

Squamates have independently evolved an elongate, limb-reduced body form numerous times. This transition has been proposed to involve either changes to regulatory gene expression or downstream modification of target enhancers to produce a homogeneous, deregionalized axial skeleton. Analysis of vertebral morphology has suggested that regionalization is maintained in snake-like body forms, but morphological variation in the other primary component of the axial skeleton, the dorsal ribs, has not been previously examined. We quantified rib morphology along the anterior-posterior axis in limbed and snake-like squamates to test different regionalization models. We find that the relative position of regional boundaries remains consistent across taxa of differing body types, including in the homoplastic evolution of snake-like body forms. The consistent retention of regional boundaries in this primaxial domain is uncorrelated with more plastic abaxial region markers. Rather than loss of regions, rib shape at the anterior and posterior of the axis converges on those in the middle, resulting in axial regions being distinguishable by allometric shape changes rather than by discrete morphologies. This complexity challenges notions of deregionalization, revealing a nuanced evolutionary history shaped by shared functions.

"Seropositive Rheumatoid Arthritis With Axial Skeleton Involvement In A 17-year-old Female Athlete."

"Seropositive Rheumatoid Arthritis With Axial Skeleton Involvement In A 17-year-old Female Athlete."

Retrospective analysis of fractures in crab-eating foxes (Cerdocyon thous)

This study assessed axial and appendicular fractures in crab-eating foxes (Cerdocyon thous; Linnaeus, 1766) admitted to the Reference Center for Wildlife. Medical records and plain radiographs of C. thous were retrospectively evaluated. Seventy-four free-ranging C. thous were admitted over 10 years, of which 21 had fractures in the appendicular and/or axial skeleton. Appendicular skeleton fracture was verified in 42.86 % of the animals, five of whom had long bone involvement and four the hip bones. More than one fracture in the appendicular skeleton occurred in 14.28 % of the animals, with the most common being a long bone fracture with a hip fracture. Axial skeleton fractures were observed in 9.52 % of the cases, with one fracture located in the vertebral column and the other in the head. Five animals died and nine were euthanized due to injury severity, prognosis and/or poor outcome after treatment. Seven animals showed good evolution after treatment, and four animals were released. In conclusion, hip bone fractures, isolated or combined with injuries to other bones of the axial and/or appendicular skeleton, were the most common injuries in C. thous. The characteristics of multiple trauma were associated with high mortality and complications.

Casamassima-Morton-Nance Syndrome and Limb-Body Wall Defect: Presentation of the Second Case and Phenotypic Assessment.

Casamassima-Morton-Nance syndrome (CMNS) is a rare disorder characterized by spondylocostal dysostosis (SCD), anal atresia, and urogenital anomalies. We describe a fetus with CMNS associated with a limb-body wall defect (LBWD), the second such case in the literature. We compare the phenotypic differences with previously reported cases, including those with segmentation anomalies of the axial skeleton, body wall defects, or absent/abnormal genitalia, revealing the consistent presence of SCD in CMNS. However, as expected, a wide phenotypic spectrum emerges, providing useful observations for fetal/neonatal screening relevant to differential diagnoses. Advanced diagnostic methods using imaging and next-generation skeletal dysplasia multi-gene panels are advisable, as they enable timely, actionable, well-informed decisions for parental counseling, potential elective termination of pregnancy, and prenatal and/or postnatal care. Most reported cases do not mention the recurrence of these usually lethal anomalies.