[Production and characterization of a glass-ceramic biomaterial and in vitro and in vivo evaluation of its biological effects]. / Bir cam-seramik biyomalzemenin üretimi, tanimlanmasi ve biyolojik etkilerinin canli-disi ve canli-içi ortamda degerlendirilmesi.

OBJECTIVES: Glass-ceramics are biomaterials that are usually produced by the sol-gel technique and can be used as a substitute for bone. One important feature of glass-ceramics is osteointegration with bone tissue. This study was designed to produce a glass-ceramic and evaluate its structure and in vitro and in vivo biological effects. METHODS: With the sol-gel method, a glass-ceramic was synthesized in the form of 30SiO2-17MgO-53Ca3(PO4)2 using tetraethylorthosilicate, dibutyl phosphate, magnesium, and calcium nitrate. Glass-ceramic jel samples were sintered at temperatures up to 1100 degrees C and their microstructure and phases were examined by the X-ray diffraction (XRD) technique and scanning electron microscopy. For in vitro tests, the samples were immersed in a simulative body fluid (SBF) for 10, 30, and 40 days to be analyzed by XRD. For in vivo tests, the samples were placed in tibial metaphyses of Sprague-Dawley rats for 4, 6, and 8 weeks for histological evaluation of osteointegration. RESULTS: As the temperature increased, growth of crystal phases was noted. While XRD analysis showed no change in samples that were kept in SBF for 10 days, hydroxyapatite crystals were seen after 30 and 40 days of SBF treatment in the second and third degree of crystal phases. In vivo test results showed that the glass-ceramic possessed a high tendency to replace osteoid bone tissue, with full osteointegration at eight weeks. CONCLUSION: The glass-ceramic produced has a high surface reactivity and can be used as a bone substitute material.

Doxycycline-induced ulceration mimicking esophageal cancer.

INTRODUCTION: Doxycycline-induced esophageal ulcer patients are mostly young persons with no history of esophageal dysfunction. Heartburn, midsternal pain and dysphagia are the most common symptoms. It has generally a benign course. The present case is the first report of doxycycline-induced extensive ulcerations, mimicking esophageal cancer in two esophageal segments alongside, in the literature. CASE PRESENTATION: This report describes a 16-year-old Caucasian girl who, while taking doxycycline capsules100 mg twice a day for acne vulgaris for 3 months, developed these symptoms. An upper endoscopy revealed multiple circumferential deep ulcerations surrounding fragile, irregular, hyperemic and hypertrophic mucosa at the level of the mid-esophagus and concomitantly in the lower esophageal sphincter. The lesions were biopsied to exclude esophageal carcinoma because of the suspicious appearance in the endoscopic examination. The histopathological examination, haematoxylin and eosin stained sections showed ulceration with a mixed inflammatory infiltrate. Doxycycline was discontinued and she was given sucralfate 1 g qid and omeprazole 20 mg bid orally. All symptoms of the patient were resolved on the third day of the treatment. After 4 weeks of the therapy, an upper endoscopic control examination demonstrated normal findings. CONCLUSION: The present case has been an uncommon presentation of doxycycline-induced extensive ulcerations, mimicking esophageal cancer in two esophageal segments, concomitantly. Even the lesions were biopsied to exclude esophageal carcinoma. A modification on the behavior of taking drugs can prevent these unpleasant complications.

Inhibitory effect of alendronate on bone resorption of autogenous free bone grafts in rats.

PURPOSE: This study was designed to investigate the effect of alendronate on the resorption of autogenous free bone grafts by biochemical and histopathologic methods. Alendronate is a potent inhibitor of osteoclast-mediated bone resorption with no adverse effect on the mineralization of bone. MATERIALS AND METHODS: In this experimental study, 56 male Wistar rats were used. Autogenous free bone grafts were prepared with standard trephine bur in the right femur of each rat. The animals were then divided into 2 groups. In the first group, rats were treated with a daily subcutaneous injection of alendronate (0.25 mg/kg/day) for 2, 4, and 12 weeks, respectively. In the second group, rats were treated with saline solution injection for the same time periods. At the end of these periods, serum and overnight fasting urine samples were collected from all animals. In serum, the level of calcium, phosphate, parathyroid hormone, and 25 dihydroxyvitamin D were measured. In urine, pyridinoline, deoxypyridinoline, calcium, and creatinine were analyzed. The rats were sacrificed at 2, 4, and 12 weeks postsurgery. The number of osteoclasts and the number and size of resorptive lacunae were evaluated histopathologically. RESULTS: Alendronate caused significant reduction in urinary pyridinoline, deoxypyridinoline levels biochemically, and the number of osteoclasts and resorptive lacunae histopathologically. CONCLUSION: Suppression of the graft resorption occurred in the alendronate-treated group.