Antiresorptive-Type and Discontinuation-Timing Affect ONJ Burden.

Osteonecrosis of the jaws (ONJ), a severe side effect of antiresorptive medications, is characterized by exposed, nonhealing bone in the oral cavity. Treatment options for ONJ range from management of symptomology to surgical resection of the affected area. Antiresorptive discontinuation, often termed a "drug holiday," has been used for managing ONJ patients. Antiresorptives can be discontinued prior to oral surgical procedures, such as tooth extraction, to prevent ONJ development or in patients with established ONJ to accelerate healing. Here, our objective was to test these clinical scenarios using the potent bisphosphonate, zoledronic acid (ZA), and the denosumab surrogate for rodents, OPG-Fc, in a rat model of ONJ. Animals were pretreated with antiresorptives or saline, after which we induced ONJ using periapical disease and tooth extraction. In our first experimental design, antiresorptives were discontinued 1 wk prior to tooth extraction, and animals were evaluated 4 wk later for clinical, radiographic, and histologic features of ONJ. In the second experiment, ONJ was established and antiresorptives were discontinued for 4 wk. Discontinuation of OPG-Fc, but not ZA, prior to tooth extraction ameliorated subsequent ONJ development. In contrast, discontinuation of either ZA or OPG-Fc in rats with established ONJ did not lead to ONJ resolution. In conclusion, our findings suggest that antiresorptive discontinuation is dependent on both the type of antiresorptive and the timing of discontinuation.

Zoledronate Impairs Socket Healing after Extraction of Teeth with Experimental Periodontitis.

Osteonecrosis of the jaws (ONJ) is a rare but severe complication of antiresorptive medications, such as bisphosphonates, used in the treatment of bone malignancy or osteoporosis. Tooth extraction and dental disease have been strongly associated with ONJ development. Here, we investigated molecular and cellular markers of socket healing after extraction of healthy or teeth with experimental periodontitis (EP) in Wistar-Han rats treated with zoledronic acid (ZA). We included 4 experimental groups: vehicle-treated animals with extraction of healthy teeth or teeth with ligature-induced EP and ZA-treated animals with extraction of healthy teeth or teeth with EP. Animals were pretreated with vehicle or ZA for a week, and EP was induced. Four weeks later, the second maxillary molars were extracted; sockets were allowed to heal for 4 wk; animals were euthanized; and maxillae were isolated. Radiographically, extraction sockets in groups 1, 2, and 3 demonstrated normal healing. Contrary incomplete socket healing was noted after extraction of teeth with EP in ZA-treated rats of group 4. Histologically, persistent inflammation and extensive osteonecrosis were seen in group 4. Disorganization of the collagen network, collagen type III predominance, and lack of collagen fiber insertion in the necrotic bone were associated with impaired socket healing. Cells positive for MMP-9, MMP-13, and α-SMA expression were present at the areas of epithelial invagination and adjacent to osteonecrotic bone. Importantly, human biopsies from patients with ONJ showed similar findings. Our data emphasize the importance of dental disease and tooth extraction in ONJ pathogenesis and help delineate an altered profile in wound-healing markers during ONJ development.

Osteogenic potential of mandibular vs. long-bone marrow stromal cells.

Although fundamentally similar to other bones, the jaws demonstrate discrete responses to developmental, mechanical, and homeostatic regulatory signals. Here, we hypothesized that rat mandible vs. long-bone marrow-derived cells possess different osteogenic potential. We established a protocol for rat mandible and long-bone marrow stromal cell (BMSC) isolation and culture. Mandible BMSC cultures formed more colonies, suggesting an increased CFU-F population. Both mandible and long-bone BMSCs differentiated into osteoblasts. However, mandible BMSCs demonstrated augmented alkaline phosphatase activity, mineralization, and osteoblast gene expression. Importantly, upon implantation into nude mice, mandible BMSCs formed 70% larger bone nodules containing three-fold more mineralized bone compared with long-bone BMSCs. Analysis of these data demonstrates an increased osteogenic potential and augmented capacity of mandible BMSCs to induce bone formation in vitro and in vivo. Our findings support differences in the mechanisms underlying mandible homeostasis and the pathophysiology of diseases unique to the jaws.

Unfavourable prognosis associated with K-ras gene mutation in pancreatic cancer surgical margins.

BACKGROUND: Despite intent to cure surgery with negative resection margins, locoregional recurrence is common in pancreatic cancer. AIMS: To determine whether detection of K-ras gene mutation in the histologically negative surgical margins of pancreatic cancer reflects unrecognised disease. PATIENTS: Seventy patients who underwent curative resection for pancreatic ductal adenocarcinoma were evaluated. METHODS: All patients had surgical resection margins (pancreatic transection and retroperitoneal) that were histologically free of invasive cancer. DNA was extracted from these paraffin embedded surgical margins and assessed by quantitative real time polymerase chain reaction to detect the K-ras gene mutation at codon 12. Detection of K-ras mutation was correlated with standard clinicopathological factors. RESULTS: K-ras mutation was detected in histologically negative surgical margins of 37 of 70 (53%) patients. A significant difference in overall survival was demonstrated between patients with margins that were K-ras mutation positive compared with negative (median 15 v 55 months, respectively; p = 0.0008). By univariate and multivariate analyses, detection of K-ras mutation in the margins was a significant prognostic factor for poor survival (hazard ratio (HR) 2.8 (95% confidence interval (CI) 1.5-5.3), p = 0.0009; and HR 2.8 (95% CI 1.4-5.5), p = 0.004, respectively). CONCLUSIONS: Detection of cells harbouring K-ras mutation in histologically negative surgical margins of pancreatic cancer may represent unrecognised disease and correlates with poor disease outcome. The study demonstrates that molecular-genetic evaluation of surgical resection margins can improve pathological staging and prognostic evaluation of patients with pancreatic ductal adenocarcinoma.

Primary lung carcinoma metastatic to a solitary fibrous tumor.

We report the case of a 78-year-old man with a 2 month history of newly diagnosed metastatic lung adenocarcinoma, who presented with a left gluteal soft tissue mass. Histological examination of the mass revealed a solitary fibrous tumor containing metastases from adenocarcinoma.

Leiomyosarcomas of the oral cavity: an unusual topographic subset easily mistaken for nonmesenchymal tumours.

AIMS: Oral leiomyosarcoma is rare and poorly documented. We aimed to characterize these lesions clinicopathologically in order to facilitate their distinction from other spindle cell neoplasms in the oral cavity. METHODS AND RESULTS: Ten cases of oral leiomyosarcoma were retrieved and studied histologically and immunohistochemically. Clinical data were obtained from referring pathologists and prior literature concerning 46 comparable cases was reviewed. Nine out of 10 cases occurred in adults; 50% arose in the jaws and four showed bone involvement. Histological appearances were similar to leiomyosarcomas elsewhere. In addition to myogenic markers, two cases were also keratin-positive. Four patients developed local recurrence or metastatic disease and three died of tumour (median follow-up 37 months). CONCLUSIONS: Leiomyosarcoma is under-recognized in the mouth, often being mistaken for a spindle-celled epithelial neoplasm. Aside from an unusual but infrequent tendency to spread to lymph nodes and a location-specific differential diagnosis, its clinicopathological features are comparable to leiomyosarcomas at other locations.

The pathology of transfusion-related acute lung injury.

Transfusion-related acute lung injury is an uncommon condition characterized by the rapid onset of respiratory distress soon after transfusion. Our understanding of its pathophysiology is based on animal models of complement (C5a) and antibody-induced lung injury and a limited number of autopsies. These models suggest that transfusion-related acute lung injury is induced by granulocytes that aggregate in the pulmonary microvasculature after activation by transfusion-derived antibodies or biologically active lipids. The published autopsy reports provide little support for this model, as they are invariably confounded by underlying pulmonary infection, preexisting disease, and resuscitation injury. We report the case of a previously well 58-year-old man who died of transfusion-related acute lung injury within 2 hours of the onset of pulmonary distress; autopsy showed evidence of massive pulmonary edema with granulocyte aggregation within the pulmonary microvasculature and extravasation into alveoli. Electron microscopy revealed capillary endothelial damage with activated granulocytes in contact with the alveolar basement membranes. These findings provide direct support for the proposed model of transfusion-related acute lung injury pathogenesis.

Extratesticular extension of germ cell tumors preferentially occurs at the hilum.

Germ cell tumors that extend beyond the testis are associated with a higher risk of metastasis. However, it is not known whether extratesticular invasion occurs at a preferential site. We reviewed all primary testicular germ cell tumors resected at the Brigham and Women's Hospital, Boston, MA, between July 1, 1987, and July 31, 1997. Of 142 total cases, 23 (16.2%) cases showed extratesticular extension. Thirty additional cases (21.1%), which had lymphatic or vascular invasion only, without interstitial involvement of extratesticular structures, were excluded. Extratesticular extension most likely occurred only at the hilum in 21 (91%) cases; 2 additional cases (9.5%) with tumor in the epididymis did not contain sections of hilum; however, the tunica albuginea was well sampled in these cases, and no separate site of tunica invasion was found. Multiple sections of the tunica albuginea were present in all cases, and penetration of the tunica albuginea was not identified in any case. Extratesticular extension was identified on gross examination of the orchiectomy specimen in only 8 of 18 (44%) cases. Extratesticular extension of germ cell tumors preferentially occurs at the hilum, and frequently the extension at this site is grossly inapparent. Histologic examination of the hilum should be performed in all cases of testicular germ cell tumors.

Atypical and malignant solitary fibrous tumors in extrathoracic locations: evidence of their comparability to intra-thoracic tumors.

Solitary fibrous tumor (SFT), first described as a pleural lesion, has been reported at numerous extrathoracic sites over the past 10 years. About 10% to 15% of intrathoracic SFTs are histologically or clinically malignant, but such cases have very rarely been described at other locations. Among 92 cases of extrathoracic SFT in our files, we identified 10 that either had recurred (2 cases) or had a least one atypical histologic feature (8 cases). The ten tumors occurred in five men and five women, 32 to 81 years old (median 56), measured 1.9 cm to 20 cm (median 11.5 cm), and were located in the abdomen/pelvis (4 cases), retroperitoneum (3 cases), groin, trunk, and upper arm. Nuclear atypia (8 cases), markedly increased cellularity (6 cases), areas of necrosis (4 cases), and greater than 4 mitoses/10 HPFs (3 cases) were seen in addition to the typical histologic features of SFT. Six tumors had at least two of these atypical histologic features. Nine cases were positive for CD34, six were positive for O-13, and one was focally positive for smooth muscle actin. Eight were excised completely. Subsequent follow-up revealed tumor relapse in eight cases (follow up 6-180 months, median 24). Four patients had local recurrence at 12 to 168 months. Distant metastasis developed at 1 to 6 years in five cases with spread to lung (2 cases), liver (4 cases), and bone. Metastasis or local recurrence developed within 2 years in five patients. To date, no patient has died of their tumor. These findings demonstrate that nuclear atypia, hypercellularity, greater than 4 mitoses/10 HPFs, and necrosis may be seen in up to 10% of extrathoracic SFTs, and are associated with, but are not by themselves predictive of, aggressive clinical behavior. In addition, our findings confirm that the behavior of extrathoracic SFTs is unpredictable, entirely comparable to that of their better known pleural counterparts, and confirm that patients with SFTs in all locations require careful, long-term follow up. It is probably unwise to regard any such lesion as definitely benign.

Extensive calcium oxalate crystal deposition in papillary renal cell carcinoma: report of two cases.

Calcium oxalate crystals are common in renal disease; however, to our knowledge they have not been reported previously in renal cell carcinoma. We report two patients with papillary renal cell carcinoma and extensive calcium oxalate crystal deposition within the tumors. Both patients had end-stage renal disease and acquired renal cystic disease. Radiographic studies demonstrated calcifications in one case. Histologically, both tumors had papillary features and had numerous calcium oxalate crystals within cystic spaces and papillae. The presence of calcium oxalate crystals in these tumors is additional evidence that papillary renal cell carcinomas and acquired cysts may be related.

Changes in size of melanocytic nevi during pregnancy.

BACKGROUND: The relation between pregnancy, melanocytic nevi, and malignant melanoma is ambiguous. It has been reported that nevi grow and darken during pregnancy. Several recent studies have shown that malignant melanomas diagnosed during pregnancy are thicker than those not associated with pregnancy. This may be partially due to a delay in diagnosis because of the opinion that benign nevi change during pregnancy. OBJECTIVE: Our purpose was to photographically document any change in size of melanocytic nevi during pregnancy. METHODS: Twenty-two women were entered into the study during the first trimester of pregnancy and examined again in the third trimester. All nevi 2 mm or larger on their back were documented and photographed. Photographs were then compared and nevi measured for change in diameter. RESULTS: Of 129 nevi, only eight nevi (6.2%) changed in diameter from the first to the third trimester. The mean change in size of all nevi studied was zero. Of the eight nevi that did change in size, four increased by 1 mm and four decreased by 1 mm. CONCLUSION: Our study suggests that pregnancy is not associated with any significant change in size of melanocytic nevi. Patient characteristics (age, pregnancy number, skin type) and nevi characteristics (location, number) did not correlate with any change in size.

Mutations caused by gamma-radiation-induced double-strand breaks in a shuttle plasmid replicated in human lymphoblasts.

The mutagenicity of open-circular DNA (containing base damage and single-strand breaks) and linear DNA (containing base damage, single-strand breaks, and one double-strand break) produced in vitro by gamma-irradiation of shuttle vector pZ189, was analysed after the plasmid's repair and replication in the human lymphoblast line, GM606. By comparing the survival, mutation frequency, and types of mutations in descendants from the two DNA forms, the effects of the double-strand break were determined. The percentage of viable plasmids from linear DNA was two-fold lower than that from open-circular DNA, 7.8 versus 14.0 (compared with unirradiated, control DNA). The mutation frequency in progenies of the open-circular plasmid was 4.2 +/- 1.7 x 10(-3), compared with 7.8 +/- 0.1 x 10(-3) in progenies of the linear DNA, again, nearly a two-fold difference. Approximately 59% of the mutations from the linear DNA were deletions and 34% were base substitutions. In contrast, only 13% of mutations from open-circular DNA were deletions, but 87% were base substitutions. All recoverable deletions were small, ranging from 1 to 205 base pairs, and the majority contained direct repeats at the deletion junctions, indicating non-homologous recombinations. Thus, mutations found among descendants from the linear and open-circular DNAs were qualitatively similar but quantitatively different. The data suggests that producing one double-strand break in DNA by ionizing radiation causes a two-fold increase in both lethality and mutation frequency.

Mutation spectrum in gamma-irradiated shuttle vector replicated in ataxia-telangiectasia lymphoblasts.

Cells from ataxia-telangiectasia (AT) patients are hypersensitive to the lethal effects of ionizing radiation. To assess radiation mutagenesis in these cells, the SV40-based shuttle vector, pZ189, was used to analyze gamma-ray-induced mutations following the plasmid's replication in AT lymphoblasts. Progenies from the AT line GM2783 exposed to 50 Gy showed a mutation frequency of 7.6 x 10(-3), 63-fold over background; surviving plasmids were 3.4% of control. Both values were essentially the same as those of irradiated plasmids replicated in a normal lymphoblast line, GM606. In addition, pZ189 exposed to 25 Gy of gamma radiation and replicated in another normal lymphoblast line and in cells of two additional AT lymphoblast lines showed similar mutation frequencies and percentages of surviving plasmids. Qualitative comparison of plasmid mutations from AT and normal cells showed no significant differences, indicating that the damaged DNA was repaired with similar fidelity in AT and normal cells. These studies suggest that there is no correlation between the enhanced sensitivity of AT cells to killing by ionizing radiation and gamma-radiation-induced mutagenesis of plasmid DNA processed in these cells.