The process of bone formation is called osteogenesis or ossification. After progenitor cells form osteoblastic lines, they proceed with three stages of development of cell differentiation, called proliferation, maturation of matrix, and mineralization. Based on its embryological origin, there are two types of ossification, called intramembranous ossification that occurs in mesenchymal cells that differentiate into osteoblast in the ossification center directly without prior cartilage formation and endochondral ossification in which bone tissue mineralization is formed through cartilage formation first. In intramembranous ossification, bone development occurs directly. In this process, mesenchymal cells proliferate into areas that have high vascularization in embryonic connective tissue in the formation of cell condensation or primary ossification centers. This cell will synthesize bone matrix in the periphery and the mesenchymal cells continue to differentiate into osteoblasts. After that, the bone will be reshaped and replaced by mature lamellar bone. Endochondral ossification will form the center of primary ossification, and the cartilage extends by proliferation of chondrocytes and deposition of cartilage matrix. After this formation, chondrocytes in the central region of the cartilage start to proceed with maturation into hypertrophic chondrocytes. After the primary ossification center is formed, the marrow cavity begins to expand toward the epiphysis. Then the subsequent stages of endochondral ossification will take place in several zones of the bone.

Introduction:The management of COVID-19 patients requires efficiency and accuracy in methods of detection, identification, monitoring, and treatment feasible in every hospital. Aside from clinical presentations and laboratory markers, chest x-ray imaging could also detect pneumonia caused by COVID-19. It is also a fast, simple, cheap, and safe modality used for the management of COVID-19 patients. Established scoring systems of COVID-19 chest x-ray imaging include Radiographic Assessment of Lung Edema (RALE) and Brixia classification. A modified scoring system has been adopted from BRIXIA and RALE scoring systems and has been made to adjust the scoring system needs at Dr. Soetomo General Hospital, Indonesia. This study aims to determine the value of scoring systems through chest x-ray imaging in evaluating the severity of COVID-19. Methods: Data were collected from May to June of 2020 who underwent chest x-ray evaluation. Each image is then scored using three types of classifications: modified score, RALE score, and Brixia score. The scores are then analyzed and compared with the clinical conditions and laboratory markers to determine their value in evaluating the severity of COVID-19 infection in patients. Results: A total of 115 patients were males (51.1%) and 110 were females (48.9%). All three scoring systems are significantly correlated with the clinical severity of the disease, with the strengths of correlation in order from the strongest to weakest as Brixia score (p<0.01, correlation coefficient 0.232), RALE score (p<0.01, correlation coefficient 0.209), and Dr. Soetomo General Hospital score (p<0.01, correlation coefficient 0.194). All three scoring systems correlate significantly with each other. Dr. Soetomo General Hospital score correlates more towards Brixia score (p<0.01, correlation coefficient 0.865) than RALE score (p<0.01, correlation coefficient 0.855). Brixia to RALE score correlates with a coefficient of 0.857 (p<0.01). Conclusion:The modified scoring system can help determine the severity of the disease progression in COVID-19 patients especially in areas with shortages of facilities and specialists.

Background:Bone marrow mesenchymal stem cells (BM-MSCs) are multipotent adult stem cells and have become an important source of cells for engineering tissue repair and cell therapy. Vascular endothelial growth factor (VEGF) promotes angiogenesis and contributes fibrous integration between tendon and bone during the early postoperative stage. Both MSCs and VEGF can stimulate cell proliferation, differentiation, and matrix deposition by enhancing angiogenesis and osteogenesis of the graft in the tunnel.Hypothesis:Injection of intratunnel BM-MSCs and VEGF enhances the early healing process of a tendon graft.Study Design:Controlled laboratory study.Methods:In this controlled animal laboratory study, each of 4 groups of rabbits underwent unilateral anterior cruciate ligament (ACL) reconstruction with use of the ipsilateral semitendinosus tendon. The rabbits received intratunnel injection of BM-MSCs and VEGF with a fibrin glue seal covering the distal tunnel at the articular site. Evaluation using magnetic resonance imaging (MRI), collagen type III expression, and biomechanical analyses were performed at 3- and 6-week intervals.Results:All parameters using MRI, collagen type III expression, and biomechanical analysis of pullout strength of the graft showed that application of intratunnel BM-MSCs and VEGF enhanced tendon-to-bone healing after ACL reconstruction.Conclusion:Intratunnel injections of BM-MSCs and VEGF after ACL reconstruction enhanced graft tunnel healing. Overall, the femoral tunnel that received BM-MSCs and VEGF had better advanced healing with increased collagen type III fibers and better outcomes on MRI and biomechanical analysis. MRI is the most reliable tool for clinical use in evaluating stages of ACL healing after reconstruction, since biopsy is an invasive procedure.

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Objectives This study aims to determine the diffusion on weighted imaging which may help in providing characterization of Apparent Diffusion Coefficient (ADC) values in benign, malignant chondrogenic and malignant non-chondrogenic bone tumors. Material and methods A retrospective study with 84 samples was conducted from October 2017 to December 2019. The samples consisted of 44 males and 40 females; the age range of 10–73 years (mean age of 32.7 years old). A Diffusion-weighted Magnetic Resonance (MR) utilizes a single-shot echo-planar imaging sequence technique with the 3T MR Scanner. We classified the types of tumors into benign, malignant chondrogenic and malignant non-chondrogenic bone tumors. The mean of ADC values from the area with lowest ADC values was selected for statistical analysis. ADC values were compared between benign, malignant chondrogenic and malignant non-chondrogenic bone tumors. Therefore, Receiver Operating Curve (ROC) analysis was done to determine optimal cut-off values. The correlation of ADC values between benign, malignant chondrogenic and malignant non-chondrogenic bone tumor with histopathologic type was also evaluated. Results The mean of ADC values from the area of benign, malignant chondrogenic and malignant non-chondrogenic bone tumor were 1.55 × 10 −3 mm 2 /s, 1.84 × 10 −3 mm 2 /s and 1.12 × 10 −3 mm 2 /s respectively. As a matter of fact, there was a significant difference between benign and malignant bone tumor with cut-off value of 1.15 × 10 −3 mm 2 /s and had a sensitivity of 82%, and a specificity of 92.3%. Moreover, a significant correlation was also found between ADC values with the histopathology type of bone tumors. Conclusion The ADC values of benign and malignant (chondrogenic and non-chondrogenic groups) bone tumors are different. Thus, the measurement of ADC values improves the accuracy of the diagnosis of bone tumors.