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Comparative investigations of odontogenic cells in normally forming teeth and tumors may provide insights into the mechanisms of the differentiation process. The present study is devoted to late phenotypic markers of ameloblast and odontoblast cells, i.e., proteins involved in biomineralization. The in situ expression of amelogenins, keratins, collagens type III and IV, vimentin, fibronectin, osteonectin, and osteocalcin was performed on normal and tumor odontogenic human cells. The pattern of protein expression showed some similarities between ameloblasts and odontoblasts present in normally developing human teeth and cells present in neoplastic tissues of ameloblastic fibroma, ameloblastic fibro-odontomas, and complex odontomas. Amelogenins (for ameloblasts) and osteocalcin (for odontoblasts) were detected in cells with well-organized enamel and dentin, respectively. In contrast, "mixed" cells located in epithelial zones of mixed odontogenic tumors co-expressed amelogenins and osteocalcin, as shown by immunostaining. The presence of osteocalcin transcripts was also demonstrated by in situ hybridization in these cells. Keratins and vimentin were detected in the same epithelial zones. Tumor epithelial cells were associated with various amounts of polymorphic matrix (amelogenin- and osteocalcin-immunoreactive), depending on the types of mixed tumors. No osteocalcin labeling was found in epithelial tumors. This study confirms that the differentiation of normal and tumor odontogenic cells is accompanied by the expression of some common molecules. Furthermore, the gene products present in normal mesenchymal cells were also shown in odontogenic tumor epithelium. These data may be related to a tumor-specific overexpression of the corresponding genes transcribed at an undetectable level during normal development and/or to an epithelial-mesenchymal transition proposed to occur during normal root formation. A plausible explanation for the results is that the odontogenic tumor epithelial cells are recapitulating genetic programs expressed during normal odontogenesis, but the tumor cells demonstrate abnormal expression patterns for these genes.

Congenital diaphragmatic hernia (CDH) is a major cause of refractory respiratory failure in the neonatal period and is characterized by persistent pulmonary hypertension of the newborn (PPHN) and pulmonary hypoplasia. Endothelin-1 (ET-1) dysregulation may play a significant role in the pathophysiology of PPHN and ET-1 acts through binding to type A (ETA) and type B (ETB) receptors. Therefore, ETA and ETB receptor protein expression was studied using immunohistochemistry in 10 lung specimens obtained from newborns with CDH, and 4 normal lung specimens, in order to explore whether dysregulation of ETA and ETB expression contributes to PPHN. ETA and ETB mRNAs were then quantified using real-time RT-PCR in laser-microdissected pulmonary resistive arteries. In the lungs of newborns with CDH, immunohistochemistry of both ETA and ETB receptors demonstrated over-expression in the thickened media of pulmonary arteries. Using laser microdissection and real-time RT-PCR, higher levels of ETA and ETB mRNA were found in CDH pulmonary arteries than in controls: this increase was more pronounced for ETA mRNA. This study provides the first demonstration of ET-1 receptor dysregulation in association with structural alteration of pulmonary arteries in newborns with CDH and PPHN. This dysregulation preferentially affects the ETA receptor. These results suggest that dysregulation of ET-1 receptors may contribute to PPHN associated with CDH.

We report the first case of cutaneous mucormycosis after a scorpion sting in Tunisia. Histopathology showed broad aseptate hyphae suggestive of a Zygomycete. Saksenaea vasiformis was identified by PCR amplification and sequencing of the fungal DNA on a cutaneous biopsy. Successful treatment was obtained by surgery and liposomal amphotericin B. CASE REPORTA previously healthy 14-year-old patient was admitted to Robert Debré hospital (Paris) with a left calf lesion following a scorpion sting in Tunisia 10 days before. At that time, he had been hospitalized for 4 days in an intensive care unit for acute renal failure and pulmonary edema induced by the scorpion venom. When he came back to France, the lesion due to the scorpion sting failed to heal.On the day of admission, the patient had a limping gait. Physical examination of the left calf revealed a painful, indurated, erythematous, 5-cm lesion. Ultrasonic tomography revealed a diffuse, soft tissue swelling. The white blood cell count was 14.1 ϫ 10 9 /liter with 71% neutrophils, the platelet count was 395 ϫ 10 9 /liter, and the C-reactive protein level was less than 10 mg/liter. The patient was started on antibacterial therapy with cefotaxime and fosfomycin according to our local guidelines for antibiotic treatment (9).On day 5, the lesion grew to a 10-cm area of swelling and induration, with a central area of black blisters. No sample was taken at this stage. The patient had a fever (38.7°C) and experienced severe pain. The white blood cell count was 18.9 ϫ 10 9 /liter with 80% neutrophils, and the C-reactive protein level was 52 mg/liter. Three blood cultures performed between day 1 and day 5 were sterile. A second ultrasonic tomography showed an extension within subcutaneous tissues, with collection of fluids. Because of the increasing area of the wound, vancomycin and metronidazole were added to the treatment regimen.On day 7, the patient required local debridement to remove devitalized tissues, including muscles and fascia. A 7-cm incision was made to evacuate the necrotizing tissue. A piece of debrided tissue was submitted for microbiological and histopathological examination. On day 12, histological analysis showed many areas of necrosis and nonspecific inflammation. Within the necrotic areas, branched, broad, nonseptate fungal hyphae suggestive of Zygomycetes were found. The material was inoculated onto routine bacteriological media and Sabouraud dextrose agar. On the Sabouraud dextrose agar, there were few colonies of filamentous fungi, with no evidence of sporulation, and the loss of viability of the isolate, possibly due to growth conditions, precluded subcultures on specific media (11), impaired any further mycological identification. All other cultures on solid media were negative for bacteria. The cutaneous biopsy, kept frozen at Ϫ80°C, was then sent to the National Reference Center for Mycoses and Antifungals, Pasteur Institute, for molecular studies. Tissues were ground, and DNA extraction was performed as previously described (16). Direct examinat...