In conclusion beta lactamase harboring
In conclusion, beta-lactamase-harboring bacteria exhibit a strong drug resistance pattern against different groups of antibiotics. Besides the production of resistance-related enzymes, these bacteria release pigments and also express different virulence BQ-788 sodium salt that might be the cause of development of the resistance pattern in P. aeruginosa. Further studies will be helpful in revealing the correlation between the drug resistance pattern and virulence factor expression.
Introduction Chondrosarcoma is the second most common type of malignant bone tumor and usually appears between the ages of 30–60 years. The tumor is characterized by cartilage formation. The pelvis, femur, and shoulder girdle are the most common sites of chondrosarcoma; the incidence at spine was reported at about 12%. Central chondrosarcoma may grow primarily in the medullary cavity of bone. The prognosis of central chondrosarcoma is related to its pathophysiology grading. The histologic classification of Evans et al depends on cellularity, cellular atypia, and mitosis. Grade 1 chondrosarcoma is classified as low-grade lesions, and grade 2 and grade 3 are classified as high-grade neoplasms. The principle modality of treatment for chondrosarcoma is en bloc surgical resection because these tumors are resistant to chemotherapy and radiation treatment. Recently, low-grade chondrosarcoma of long bones has increasingly been treated with intralesional curettage and local adjuvant therapy due to its slow growth and low metastatic tendency. However, some authors argued that inadequate local treatment with an intralesional management results in higher local recurrence. We hypothesized that advanced intralesional treatment, using chemical agents and cryoablation, for central grade I chondrosarcomas would have similar rates of local recurrence and metastasis as wide excision treatment. The aims of this retrospective study were to review the experience of surgical treatment of central low-grade chondrosarcoma, to assess the long-term clinical and oncological outcomes between intralesional curettage and wide excision, and to compare the results of the two surgical managements.
Methods A retrospective search of our departmental database identified 48 patients with low-grade chondrosarcoma from 1998 to 2013. We excluded 3 patients with locally recurrent or metastatic disease at present and 22 patients diagnosed with so-called borderline, Grade 1–2 chondrosarcoma from preoperative biopsy. In addition, we excluded three patients with secondary chondrosarcoma, two with extraosseous lesions, and seven with stage IB chondrosarcoma. The final cohort included 11 patients whose medical records, histological sections, and radiography were reviewed. The patients were divided into two groups; patients in Group A (n=7) were treated with extended intralesional curettage, whereas patients in Group B (n=4) were treated with wide excision and reconstructive surgery (Table 1). The tumors affected appendicular bone in eight patients (75%) and axial bone in three patients (25%). There were three distal femurs (two in Group A and one in Group B), one proximal femur (Group A), three proximal humerus (two in Group A and one in Group B), one humeral shaft (Group B), and three acetabulums (two in Group A and one in Group B). In our database, low-grade chondrosarcoma represented 48.5% (48/99) of all chondrosarcoma patients, and stage IA chondrosarcoma accounted for 22.9% of low-grade patients. There were six male and five female patients with a mean age at surgery of 43.8±17.6 years (range, 20–71 years), with a significant difference (p=0.006) in age between treatment cohorts (Table 2). The average duration of follow-up for the patients was 68.7±50.9 months (range, 19–194 months). The average lesion size was 8.9±2.7 cm (range, 3–18cm, p=0.216). The surgical indication in our institution was painful lesion with aggressive radiologic patterns. All the patients had preoperative pathology, either needle biopsy or excisional biopsy, with the specimen reviewed by two experienced pathologists. Imaging study, computed tomography (CT) scan, or magnetic resonance imaging (MRI) was also obtained to evaluate bone expansion, tumor length, and active periostitis. Depending on the site and size of the tumor, we explained the surgical management options, extended curettage and wide excision, and their respective disadvantages and advantages to the patient and/or their family. The surgeon and patient together made the final surgical management decision. For the acetabulum lesion, two of the three patients chose intralesional curettage to minimize the surgical risk. For the periarticular chondrosarcoma, we performed reconstructive surgery after wide excision to restore the function of the patient. In some patients with large bone defect after excision, we used recycled bone prepared by extracorporeal irradiation with 20,000 rad or liquid nitrogen soaking. For the patients of curettage, we removed the lesions macroscopically using curets and high-speed burr when the margin was well protected with warm gauze to prevent contamination by spray (Fig. 1). The margin of the lesion was determined by both the cortical border and intramedullary canal, which were mapped by MRI or CT scan preoperatively. A solution of phenol was applied to the remaining bone cavity for 3 minutes with a surgical swab, and then the cavity was rinsed with 95% ethanol solution. Subsequently, massive normal saline (> 2000 mL) irrigation was performed. Cryotherapy with liquid nitrogen was used in selected patients who could be safely applied without injury of surrounding soft tissues. Finally, the defect that was made by curettage was filled with allograft bone chips, and if necessary, internal fixation was applied to reinforce the affected bone. For Patients 3, 4, and 8, arthroplasty was also performed to address destruction of articular surface (Fig. 2).