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Biomedical subjects

Rita Kandel

Publications and source records attributed to Rita Kandel.

15 recordsLinked to original sources
PubMed2006

Cartilage T2 assessment: differentiation of normal hyaline cartilage and reparative tissue after arthroscopic cartilage repair in equine subjects.

PURPOSE: To prospectively assess T2 mapping characteristics of normal articular cartilage and of cartilage at sites of arthroscopic repair, including comparison with histologic results and collagen organization assessed at polarized light microscopy (PLM). MATERIALS AND METHODS: Study protocol was compliant with the Canadian Council on Animal Care Guidelines and approved by the institutional animal care committee. Arthroscopic osteochondral autograft transplantation (OAT) and microfracture arthroplasty (MFx) were performed in knees of 10 equine subjects (seven female, three male; age range, 3-5 years). A site of arthroscopically normal cartilage was documented in each joint as a control site. Joints were harvested at 12 (n = 5) and 24 (n = 5) weeks postoperatively and were imaged at 1.5-T magnetic resonance (MR) with a 10-echo sagittal fast spin-echo acquisition. T2 maps of each site (21 OAT harvest, 10 MFx, 12 OAT plug, and 10 control sites) were calculated with linear least-squares curve fitting. Cartilage T2 maps were qualitatively graded as "organized" (normal transition of low-to-high T2 signal from deep to superficial cartilage zones) or "disorganized." Quantitative mean T2 values were calculated for deep, middle, and superficial cartilage at each location. Results were compared with histologic and PLM assessments by using kappa analysis. RESULTS: T2 maps were qualitatively graded as organized at 20 of 53 sites and as disorganized at 33 sites. Perfect agreement was seen between organized T2 and histologic findings of hyaline cartilage and between disorganized T2 and histologic findings of fibrous reparative tissue (kappa = 1.0). Strong agreement was seen between organized T2 and normal PLM findings and between disorganized T2 and abnormal PLM findings (kappa = .92). Quantitative assessment of the deep, middle, and superficial cartilage, respectively, showed mean T2 values of 53.3, 58.6, and 54.9 msec at reparative fibrous tissue sites and 40.7, 53.6, and 61.6 msec at hyaline cartilage sites. A significant trend of increasing T2 values (from deep to superficial) was found in hyaline cartilage (P < .01). Fibrous tissue sites had no significant change with depth (P > .59). CONCLUSION: Qualitative and quantitative T2 mapping helped differentiate hyaline cartilage from reparative fibrocartilage after cartilage repair at 1.5-T MR imaging.

Animals↗
PubMed2005

Granular cell tumor of the extremity: magnetic resonance imaging characteristics with pathologic correlation.

OBJECTIVE: The purpose of this study is to delineate the magnetic resonance (MR) appearance of a granular cell tumor (GrCT) of the extremity and to correlate the imaging appearance with the microscopic findings. DESIGN AND PATIENTS: A retrospective review of five patients with a histopathologic diagnosis of GrCT and pre-operative MR imaging of the neoplasm was done. The images were reviewed by two musculoskeletal radiologists in a consensus fashion. Lesion location, size, shape, margination, and signal intensity characteristics were assessed. MR findings were correlated with histopathological examination. RESULTS: The benign subtype of GrCT is usually isointense or brighter than muscle on T1-weighted sequences, round or oval in shape, superficial in location, and 4 cm or less in size. On T2-weighted sequences, benign lesions may demonstrate a high peripheral signal, as well as a central signal intensity that is isointense to muscle or suppressed fat. A significant stromal component in the tumor and, hypothetically, a ribbon-like arrangement of tumor cells may influence the signal intensity demonstrated on the T1 and T2-weighted sequences. The malignant subtype may demonstrate signal intensity characteristics and invasion of adjacent structures often seen with other aggressive neoplasms; sizes larger than 4 cm and association with major nerve trunks can be seen. CONCLUSION: Benign GrCT has imaging characteristics which may distinguish this tumor from other soft tissue neoplasms, as well as the malignant type of this tumor.

Adolescent↗
PubMed2005

Late radiation morbidity following randomization to preoperative versus postoperative radiotherapy in extremity soft tissue sarcoma.

BACKGROUND AND PURPOSE: This study compared late radiation morbidity in patients with extremity soft tissue sarcoma randomized to treatment by pre- (50 Gy) or postoperative (66 Gy) radiotherapy in combination with surgery. The morbidities evaluated included fibrosis, joint stiffness and edema at 2 years following treatment. The impact of morbidity on patient function as measured by the Musculoskeletal Tumor Rating Scale (MSTS) and the Toronto Extremity Salvage Score (TESS) was also evaluated. PATIENTS AND METHODS: 129 patients were evaluated. Toxicity rates were compared by treatment arm using the Fisher's exact test. Function scores by toxicity were analyzed using the Wilcoxon rank sum test. Multivariate logistic regression was used to evaluate the joint effect of treatment arm, field size, and dose on subcutaneous tissue fibrosis, joint stiffness and edema. RESULTS: 27 of 56 patients (48.2%) in the postoperative arm compared to 23 of 73 (31.5%) in the preoperative arm had grade 2 or greater fibrosis (P = 0.07). Although not statistically significant, edema was more frequent in the postoperative arm, 13 of 56 (23.2%) versus 11 of 73 (15.5%) in the preoperative arm, as was joint stiffness, 13 of 56 (23.2%) versus 13 of 73 (17.8%). Patients with significant fibrosis, joint stiffness or edema had significantly lower function scores on both measures (all P-values < 0.01). Field size was predictive of greater rates of fibrosis (P = 0.002) and joint stiffness (P = 0.006) and marginally predictive of edema (P = 0.06). CONCLUSIONS: Patients treated with postoperative radiotherapy tended to have greater fibrosis. Fibrosis, joint stiffness and edema adversely affect patient function.

Adolescent↗
PubMed2005

von Willebrand factor expression in osteosarcoma metastasis.

A number of genes are implicated in the initiation and progression of osteosarcoma; however, cytogenetic and comparative genomic hybridization studies indicate the involvement of additional unidentified genes. An examination of gene expression profiles in 22 high-grade osteosarcoma tumor specimens from 15 patients (including paired primary and metastatic samples from five patients) indicated that von Willebrand factor (vWF) mRNA expression may increase during tumor progression. vWF, a large glycoprotein previously considered to be expressed exclusively by endothelial cells and megakaryocytes, is involved in platelet aggregation and adhesion to the subendothelial matrix, processes critical to hematogenous tumor cell metastasis to the lung. Analysis of paired primary and metastatic osteosarcoma tumor samples from 10 patients revealed an increase in vWF gene expression in metastases (P=0.005). Immunohistochemistry showed that, in addition to the endothelial cells, vWF protein was also detected in osteosarcoma cells in vivo in 13 of 29 tumor specimens as well as in SAOS2, an osteosarcoma cell line. The tumor cell staining correlated positively with high vWF expression in the sample (P=0.006). Although vascular endothelial cells contribute to the vWF mRNA detected in the tumor samples, there was neither any correlation between vascular density (VD) and vWF mRNA expression nor between VD and clinical outcome. These findings suggest that vWF expression is deregulated in osteosarcoma tumors, potentially contributing to metastasis.

Bone Neoplasms↗
PubMed2004

Primary synovial osteochondromatosis of the hip: extracapsular patterns of spread.

OBJECTIVE: To identify patterns of extracapsular extension of synovial osteochondromatosis of the hip. DESIGN AND PATIENTS: Seven cases of synovial osteochondromatosis of the hip were retrospectively reviewed. Imaging performed included conventional radiography ( n=7), arthrography ( n=1), CT ( n=3) and MR imaging ( n=3). Disease extent on imaging was assessed for each patient and the presence of intra-articular effusion, capsular abnormality and osteochondral bodies recorded. The presence and distribution of extra-articular spread was also assessed and correlated with the surgical findings. In all cases diagnosis was confirmed by biopsy, with all patients undergoing tumor resection with or without synovectomy. RESULTS: In five cases (5/7) disease extended beyond the hip capsule, while the remaining two cases (2/7) were confined to the hip joint. These findings were confirmed at surgery. Two distinct patterns of extracapsular spread were identified. The first pattern, noted in three cases, involved tumor extension along iliopsoas. The second pattern, noted in five cases, involved tumor extension along the obturator externus fat plane. In three cases both patterns were present. CONCLUSIONS: Extra-articular spread of synovial osteochondromatosis is common. Patterns of extra-articular spread may be predictable based on involvement of recognized periarticular bursae of the hip joint. Bursal patterns of extra-articular spread include extension into the iliopsoas bursa as well as communication along the obturator externus bursa of the hip.

Adult↗
PubMed2004

Central giant cell granuloma of the jaws: assessment of cell cycle proteins.

BACKGROUND: Several reports have demonstrated the presence of a high proliferative activity in central giant cell granuloma, raising the possibility that deregulation of the cell cycle may contribute to its pathogenesis. As we identified alterations of cyclin D1 in giant cell tumor of bone, and as there are histologic similarities between central giant cell granuloma and giant cell tumor, we assessed jaw lesions for the presence of similar alterations. METHODS: Formalin-fixed, paraffin-embedded tissue from 29 cases of central giant cell granuloma was assessed for the expression of cyclin D1, cyclin B1, and MIB-1 (Ki-67) using immunohistochemistry. In addition, differential polymerase chain reaction (PCR) was used to determine whether there was cyclin D1 gene amplification. RESULTS: The cyclin D1 gene copy number appeared to be minimally elevated in 31% of the cases. Cyclin D1 protein overexpression was observed in 28 of 29 cases (96.5%). Immunostaining was present predominantly in the nuclei of the giant cells. Cyclin B1 and MIB-1 immunoreactivity was restricted to the mononuclear cells with no staining present in the giant cells. CONCLUSIONS: Cyclin D1 protein overexpression may be involved in the formation of the giant cells and the pathogenesis of central giant cell granuloma. As the distribution of immunostaining is identical to that observed in giant cell tumor of bone, our results support the possibility that central giant cell granuloma of the jaws and giant cell tumor of bone represent a similar disease process that clinically and histologically may have somewhat different features because of differences in the anatomical site of involvement.

Cell Cycle Proteins↗
PubMed2003

Misclassification in a matched case-control study with variable matching ratio: application to a study of c-erbB-2 overexpression and breast cancer.

We provide a simple analytic correction for risk factor misclassification in a matched case-control study with variable numbers of controls per case. The method is an extension of existing methodology, and involves estimating the corrected proportions of controls and cases in risk factor categories within each matched set. These estimates are then used to calculate the Mantel-Haenszel odds ratio estimate corrected for misclassification. A simulation-based interval estimate is developed. An example is given from a study of risk factors for progression of benign breast disease to breast cancer, in which the risk factor is a biological marker measured with poor sensitivity.

Breast Neoplasms↗
PubMed2003

Low-grade liposarcoma with osteosarcomatous dedifferentiation: radiological and histological features.

We describe the radiological and pathological findings of a rare case of a low-grade liposarcoma associated with a high-grade osteosarcomatous component in a 78-year-old woman. Pre-operative imaging demonstrated a well-encapsulated homogeneous fatty tumour in the right buttock deep to the gluteal musculature. Centrally within the fatty tumour a region of increased soft tissue attenuation on CT and heterogeneous high signal on fat-saturated T2-weighted MRI was seen with amorphous calcification/ossification. Histological assessment revealed a low-grade liposarcoma containing an area of dedifferentiation that resembled an osteosarcoma. We describe the radiological-pathological findings in this rarely reported clinical entity and discuss the differential diagnosis of calcification within lipomatous tumours.

Aged↗
PubMed2003

Cyclin alterations in giant cell tumor of bone.

Cyclins play an important role in regulating the passage of dividing cells through critical checkpoints in the cell cycle. Because alterations of several cyclins, especially cyclin D1, have been implicated in the development of many human neoplasms, we examined 32 cases of giant cell tumor of long bones for cyclin D1 gene amplification and protein overexpression using differential polymerase chain reaction and immunohistochemistry, respectively. In addition, the expression of cyclin D3, cyclin B1, and the proliferation-associated antigen Ki-67 (MIB-1) was assessed immunohistochemically. Low-level cyclin D1 gene amplification was detected in 61% of giant cell tumor cases. All tumors showed cyclin D1, cyclin D3, cyclin B1, and Ki-67 (MIB-1) staining; however, the distribution was very characteristic. Cyclin D1 protein expression was seen predominantly in the nuclei of the giant cells, with occasional mononuclear cells staining. There was no correlation between cyclin D1 gene amplification and protein overexpression. Cyclin D3 staining showed a similar distribution, with 88% of cases showing protein overexpression. Cyclin D1 and/or D3 staining in the giant cells was never associated with staining for either cyclin B1 or Ki-67 (MIB-1), as the expression of the latter two proteins was restricted to the mononuclear cells. Cyclin B1 overexpression was seen in 44% of cases. Ki-67 (MIB-1) staining was present in all cases, and between 10 to 50% of the mononuclear cells were positive. These results suggest that alterations in cyclin D1 and/or D3 might play a role in the pathogenesis of giant cell tumor of bone.

Adolescent↗
PubMed2002

Preoperative versus postoperative radiotherapy in soft-tissue sarcoma of the limbs: a randomised trial.

BACKGROUND: External-beam radiotherapy (delivered either preoperatively or postoperatively) is frequently used in local management of sarcomas in the soft tissue of limbs, but the two approaches differ substantially in their potential toxic effects. We aimed to determine whether the timing of external-beam radiotherapy affected the number of wound healing complications in soft-tissue sarcoma in the limbs of adults. METHODS: After stratification by tumour size (< or = 10 cm or >10 cm), we randomly allocated 94 patients to preoperative radiotherapy (50 Gy in 25 fractions) and 96 to postoperative radiotherapy (66 Gy in 33 fractions). The primary endpoint was rate of wound complications within 120 days of surgery. Analyses were per protocol for primary outcomes and by intention to treat for secondary outcomes. FINDINGS: Median follow-up was 3.3 years (range 0.27-5.6). Four patients, all in the preoperative group, did not undergo protocol surgery and were not evaluable for the primary outcome. Of those patients who were eligible and evaluable, wound complications were recorded in 31 (35%) of 88 in the preoperative group and 16 (17%) of 94 in the postoperative group (difference 18% [95% CI 5-30], p=0.01). Tumour size and anatomical site were also significant risk factors in multivariate analysis. Overall survival was slightly better in patients who had preoperative radiotherapy than in those who had postoperative treatment (p=0.0481). INTERPRETATION: Because preoperative radiotherapy is associated with a greater risk of wound complications than postoperative radiotherapy, the choice of regimen for patients with soft-tissue sarcoma should take into account the timing of surgery and radiotherapy, and the size and anatomical site of the tumour.

Aged↗
PubMedDate not supplied

Leiomyosarcoma of the inferior vena cava.

Leiomyosarcoma of the inferior vena cava is a rare neoplasm; however, it is the most frequent tumor of vascular origin. It is classified according to site of origin that reflects its clinical presentation and prognosis. They are generally recognized to be of smooth muscle cell origin. Surgical resection is the treatment of choice. The role of adjuvant therapy for leiomyosarcoma is not established.

Aged↗
PubMedDate not supplied

Model of radiation-impaired healing of a deep excisional wound.

Despite many well-recognized benefits, administration of ionizing radiation before surgical resection of malignancies is associated with a high risk of wound-healing complications. Most animal models investigating techniques to improve wound healing use a superficial wound. The goal of this study was to develop a novel model of radiation-impaired healing using a deep excisional wound, which is closer to the clinical situation. In the first part of this study, female Lewis rats were exposed to 0, 12, 15, or 18 Gy single-fraction radiation to the buttocks. Three weeks later, deep wounds were created by excision of the gluteus maximus muscle. Irradiated wounds had a lower rate of healing of the surgically created defect than unirradiated wounds (p<0.001), but there was no significant difference between the different doses of radiation. Impaired healing was still evident at 12 weeks. The second part of this study investigated the ability of porcine small-intestinal submucosa (SIS) to improve healing in this animal model. At 6 weeks, wounds implanted with SIS showed improved healing at all doses of radiation compared with unimplanted irradiated wounds. However, higher doses of radiation were still associated with a lower rate of healing. SIS induced a cellular response that was not evident in defects that did not receive SIS, suggesting that SIS has the potential to stimulate repair. This reproducible model of radiation-impaired wound healing closely resembles the clinical setting. The results indicate that this model can be used to investigate new biomaterials as possible therapeutic agents to enhance wound healing.

Animals↗
PubMedDate not supplied

Radiographic, CT, and MR imaging features of dedifferentiated chondrosarcomas: a retrospective review of 174 de novo cases.

Up to 11% of chondrosarcomas may undergo regional anaplastic change, resulting in a high-grade noncartilaginous sarcoma arising within a typically low-grade chondrosarcoma. Known as dedifferentiated chondrosarcomas, these tumors are highly malignant with a very poor prognosis. The most important factor affecting survival is an accurate preoperative diagnosis. Therefore, the ability to predict the possibility of dedifferentiation in a malignant cartilage tumor on the basis of imaging findings is critical to ensure adequate tumor sampling at the time of biopsy. Imaging findings at radiography, computed tomography (CT), and magnetic resonance (MR) imaging in 174 patients with dedifferentiated chondrosarcoma were reviewed to determine whether there are radiologic features that can help predict dedifferentiation. On approximately one-third of the radiographs, one-third of the MR images, and one-half of the CT scans, the tumors demonstrated bimorphic features (ie, distinctly different tumor features juxtaposed within the lesion), most frequently a dominant lytic area adjacent to a mineralized tumor at radiography and a large, unmineralized soft-tissue mass associated with an intraosseous chondroid-containing tumor at CT and MR imaging. In the initial evaluation of patients with a primary bone tumor, thorough evaluation of the radiologic features of the entire tumor is critical.

Adolescent↗