The effects of thermal injury on immature rat ear cartilage.

The purpose of this study was to research regeneration and growing properties of an immature rat ear cartilage and its adjacent tissue after a thermal injury. Fifteen 30-day-old male Sprague-Dawley rats were used. Burn wounds were created by applying a heated plaque. All the rats, based on their tissue sampling day, were placed in two groups for histopathologic evaluation. In group I (n = 5), the burned right auricles were amputated on the first day,and the left auricles were amputated as a control at the same time. In group II (n = 10), the burned right auricles were amputated on the 30th day, and the left auricles were amputated as a control at the same time. Epithelization of skin was completed in period ranging between 12 and 15 days in all burned ears. The skin appendages were few throughout the affected area.Chondroid tissue regenerated from perichondrium and increased capillary vessels were observed.On the first day of the burn injury, electron microscopic findings were karyopyknosis, karyorrhexis, and karyolysis of the nucleus, and there were also signs of necrosis. New chondroblasts were formed around the collagen fibrils in the scar tissue on the 30th day. CD-31 immunohistochemical staining showed increased capillary vessels in the burned ear. The peripheral nerve fibers decreased and regenerative signs of nerves were shown with the use of S-100 immunohistochemical staining. Differentiation of chondroblasts to chondrocytes occurs in the burned immature ear, and new cartilage tissue regenerates from perichondrium. In addition, regenerative signs of nerves appear.

The protective effects of melatonin and vitamin E against renal ischemia-reperfusion injury in rats.

Reactive oxygen species (ROS) were shown to contribute to the cellular damage induced by ischemia-reperfusion. The purpose of this study was to investigate and compare the efficiency of melatonin and vitamin E in the reduction of injury induced by ROS in a rat model of renal ischemia-reperfusion. Twenty-four Wistar-albino rats were divided into four groups. Rats in the Sham group were given saline 1 mL/kg, intraperitoneally (ip) 72 h, 48 h, 24 h, and 30 min before the sham operation. Rats in ischemia-reperfusion (IR), IR+Melatonin, and IR+Vitamin E groups were given saline (1 mL/kg), melatonin (10 mg/kg), and vitamin E (100 mg/kg) ip, respectively, 72 h, 48 h, 24 h, and 30 min before the ischemia for 60 min, followed by reperfusion for 60 min. The blood samples and kidney tissues of the rats were taken under anesthesia. Ischemia-reperfusion significantly increased urea, creatinine, and malondialdehyde (MDA) levels, and decreased superoxide dismutase (SOD) and catalase (CAT) activities. Histopathological findings of the IR group confirmed that there was renal impairment by cast formation and tubular necrosis in the tubular epithelium. In the IR+Melatonin group, while MDA levels significantly decreased, SOD activities increased. In the IR+Melatonin group, the level of tubular necrosis and cast formation are significantly decreased than those seen in the ischemia-reperfusion group. Melatonin in particular was effective to reverse hot ischemia of kidney by its antioxidant effects. These results may indicate that melatonin pretreatment protects against functional, biochemical, and morphological damage better than vitamin E in renal ischemia-reperfusion injury.

Oncocytic carcinoma of the parotid gland.

BACKGROUND: Oncocytic carcinoma is a rare tumor of major salivary glands. Despite being described 5 decades ago, not much is known about these rare tumors. Histochemical or electron microscopic confirmation of the oncocytic nature of the tumor cell is needed for differential diagnosis. The main treatment modality is surgery with or without adjuvant radiotherapy. Malignant oncocytomas have the potential risk of developing distant metastases and demand long term follow-up after therapy. CASE REPORT: A 58-year old man presented with a recurrent mass in the left parotid gland with a prior diagnosis of monomorphic adenoma in the same localization which had been treated by tumor excision in July 2002. Left superficial parotidectomy followed by radiotherapy into tumor bed and upper neck were carried out in September 2004. To date, he has had no evidence of recurrence for 14 months. CONCLUSION: For an accurate approach in the management of patients, oncocytic adenocarcinoma should be considered in the differential diagnosis of lesions of the parotid gland, most of which are benign.

Use of mometasone furoate aqueous nasal spray in the treatment of rhinitis medicamentosa: an experimental study.

OBJECTIVE: We aimed to investigate, histopathologic changes in the nasal mucosa of guinea pig's after prolonged administration of oxymetazoline and the development of rhinitis medicamentosa, and the efficacy of mometasone furoate aqueous nasal spray and saline in reversing the ultrastructural changes attributable to rhinitis medicamentosa. METHODS: In the study, 24 male guinea pigs (500 to 600 gr) were used. Oxymetazolin (0.05%) was sprayed into the nasal cavities of the guinea pigs 3 times daily for 8 weeks. At the end of this period, 6 guinea pigs were killed and examined to make sure that the animals had developed rhinitis medicamentosa. The remaining guinea pigs were randomly divided into 3 groups. In the first group, one spray-puff of 0.05% mometasone furoate aqueous nasal spray (50 microg) was applied twice daily for 14 days. In the second group, saline solution (0.9% NaCl) was applied twice daily for 14 days. No treatment was performed in the third group. At the end of the treatment period, nasal mucosal changes were evaluated by light microscopy and electron microscopy. RESULTS: After oxymetazolin application for 8 weeks, the main histologic changes were edema, congestion, proliferation of subepithelial glands, and squamous cell metaplasia. After topical mometasone furoate aqueous spray application for 2 weeks, the edema fluid was found to diminish markedly. In the saline and no treatment groups, edema and congestion continued. In these groups of guinea pigs, fibrosis has been seen in the nasal mucosa. CONCLUSION: We found that mometasone furoate nasal spray was effective against experimentally induced rhinitis medicamentosa in guinea pigs. Mometasone furoate nasal spray may have value in the treatment of patients with rhinitis medicamentosa.

The effect of nadroparine on coagulation mechanisms: ultrastructural analysis.

Low molecular weight heparins are widely used in the prophylaxis and treatment of thrombotic disorders. The effect of low molecular weight heparins on coagulation was examined ultrastructurally in an animal model. A test and a control group was formed, each consisting of five rabbits. Nadroparine (225 Institute of Chaoy Unit/kg twice daily) was applied to the test group for 10 days. The control group received 1 ml saline solution subcutaneously. Blood and vascular tissue samples collected at the end of the 10th day were evaluated under a JEM 100 B electron microscope. Platelet degranulation and agglutination was observed in the control group. Fibrin materials were detected in the cytoplasms and surroundings of degranulated platelets. Erythrocyte accumulation was remarkable on the vascular endothelium with intact coagulation periods. In the test group, outer membranes of platelets, hyalomere, and granular structures in the granulomeres were detected to be nearly intact. There were rare erythrocytes in the large vascular lumens. The aggregation phase had occurred but no agglutination was detected. Nadroparine seems to preserve consistency of lipoprotein membranes of platelets and granular structures containing enzymes, which contribute to the coagulation mechanisms.