Catechol estrogens may mediate estrogen-induced carcinogenesis because 4-hydroxyestradiol induces DNA damage and renal tumors in hamsters, and this metabolite is formed in the kidney and estrogen target tissues by a specific estrogen 4-hydroxylase. We examined the carcinogenic potential of catechol estrogen in an experimental model previously reported to result in a high incidence of uterine ad...

INTRODUCTION Cardiac myxoma is a benign neoplasm representing the most common primary cardiac tumor in adults, however it is unusual in neonates. It is represented by an endocardial mass that occupies the cardiac chamber. Although the majority of myxomas are attached to the fossa ovalis of the interatrial septum, they also attach to the walls of the cardiac chambers and to valve leaflets surfac...

PC12 rat pheochromocytoma cells form tumors when transplanted into the forebrains of 1-4-day-old neonatal rats; thereafter, the incidence of tumor formation declines rapidly with increasing recipient age. The fate of PC12 cells transplanted into the forebrains of older neonates is thus not well defined. To examine the interactions of PC12 cells with this older neural environment, we transplante...

Normal human cells whether embryonic, neonatal, or adult are resistant to experimentally induced tumorigenesis in contrast to rodent or chicken cells. We showed previously that neither transformation with simian virus 40 DNA nor transfection with human mutant HRAS DNA immortalized FS-2 cells (diploid, neonatal human fibroblasts). Further, tumorigenicity was not induced, despite expression of th...

Our discovery that the perinatal period involves nucleotide modifications and gene overexpression in mouse lung prompted us to evaluate whether mice may become more susceptible to cigarette smoke when exposure starts immediately after birth. We previously showed that mainstream cigarette smoke is a quite potent carcinogen in neonatal mice. Further on, we showed that exposure of mice to environm...

Transplantation of adenovirus type 2-transformed cell-induced newborn tumor lines to different aged hamsters revealed that the cell-mediated host defenses responsible for tumor graft rejection matured early in the second week of life. When light microscopic examinations were performed during the course of tumor development, the primary histopathological difference between progressing tumors rem...

background and aim: the inferior alveolar canal must be constantly examined as an important anatomical landmark in the study of lower jaw, particularly posterior body and mandibular ramus sites, in dental and surgical procedures. in the present study, the effect of two pathological lesions, ameloblastomas and keratocystic odontogenic tumour, on canal displacement were investigated. materials an...

background. the aim of this study was to investigate myofibroblast (mf) density in a broad spectrum of odontogenic cysts and tumors and the relation between the density of mfs and the clinical behavior of these lesions. methods. a total of 105 cases of odontogenic lesions, including unicystic ameloblastoma (uam), solid ameloblastoma (sa), odontogenic keratocyst (okc), dentigerous cyst (dc), rad...

we have studied the patients who had a neck mass on presentation in five medical centers of tehran univ. of medical sciences (infectious disease department, ent department, dentistry faculty, cancer institute) during a period of 14 months. sixty patients, 20 women and 40 men, were eligible for our study. all patients underwent clinical and paraclinical work up and finally had histologic diagnos...

introduction: solitary fibrous tumor is a rare, mesenchymal neoplasm that has been reported in numerous sites. occurrence in the parotid gland is exceedingly rare.   case report: a 53-year-old man with a 2 cm solitary fibrous tumor of the left parotid gland, that was observed clinically and operatively and thought to be a neoplasm arising from stensen's duct, is described. a pre-operative ...