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Biomedical subjects

A Armin

Publications and source records attributed to A Armin.

15 recordsLinked to original sources
PubMed1997

Pulsed low dose rate brachytherapy in a rat model: dependence of late rectal injury on radiation pulse size.

PURPOSE: Clinical protocols utilizing pulsed low dose rate brachytherapy (PDR) to replace traditional continuous low dose rate brachytherapy (CLDR) employ irradiation in individual pulses given at intervals of a few hours. A critical factor in determining whether PDR will produce equivalent or greater late-occurring normal tissue toxicity is the dose per pulse. A rat rectal model was used to determine the role of pulse size in modifying dose effectiveness in producing late-occurring toxicity. METHODS AND MATERIALS: A rat model in which the rectum is irradiated with 192Ir sources was used in conjunction with an intracavitary applicator. A section of rectum 1.3 cm in length was irradiated with either 0.75 Gy/h CLDR or one of five schemes of PDR. The schemes applied 0.375, 0.75, 1.5, 3.0, or 6.0 Gy pulses at 0.5, 1.0, 2.0, 4.0, or 8.0 h intervals, respectively. Rats were observed for up to 300 days after completion of irradiation for rectal obstruction. Rectal specimens were taken at the time of sacrifice for obstruction or at the end of follow-up and analyzed histologically for injury. RESULTS: Effectiveness of irradiation was analyzed by calculating the ED50 for incidence of obstruction and severe histological injury. The ED50 for obstruction after treatment with CLDR and pulse sizes of 0.375, 0.75, and 1.5 Gy were 70.5, 68.0, 68.6, and 68.8 Gy, respectively. These values were not significantly different. Compared to CLDR, the ED50 for obstruction after pulse sizes of 3.0 and 6.0 Gy were significantly different at 60.9 and 46.3 Gy, respectively. The relative changes in ED50 for the different radiation schemes in producing ulceration, fibrosis, and vascular sclerosis injury were similar to that observed for obstruction. The endpoints of colitis cystica profunda and atypical epithelial regeneration varied less with increasing pulse size. CONCLUSIONS: We have demonstrated that for late rat rectal injury, dose responses to PDR pulse sizes up to 1.5 Gy at 2-h intervals are not distinguishable from that seen with CLDR at a dose rate of 0.75 Gy/h.

Animals↗
PubMed1991

Peutz-Jeghers-like melanotic macules associated with esophageal adenocarcinoma.

A 67-year-old white man with esophageal adenocarcinoma presented with Peutz-Jeghers-like macules on the lips, face, nipples, and rectal mucosa. Pathological examination of the macules showed atypical melanocytes in the epidermis. The pleomorphic large melanocytes resembled the neoplastic cells seen in melanoma in situ. This is the first report of proliferation of atypical melanocytes in Peutz-Jeghers-like melanosis associated with a primary esophageal adenocarcinoma.

Adenocarcinoma↗
PubMed1988

Expression of endothelial cell markers PAL-E and EN-4 and Ia-antigens in Kaposi's sarcoma.

Eleven biopsy specimens of Kaposi's sarcoma (KS) removed from the skin and oral mucosa were examined immunohistochemically with monoclonal antibodies PAL-E and EN-4, specific for human vascular endothelial cells, and with LN-3 monoclonal antibody reactive with immune-associated (Ia) antigens in the HLA-DR locus. The early lesions of KS, corresponding to the patch phase, contained hyperplastic venules and an increased number of lymphatic capillaries. The lymphatic capillary endothelium was reactive with EN-4, whereas, PAL-E reacted only with blood vessel endothelial cells. The spindle cells, like lymphatic endothelial cells, were non-reactive with PAL-E but showed positive reaction with EN-4 antibodies. The observed morphologic pattern of vasculogenesis and the demonstrated immune-reactivity in KS support an origin from the venule-lymphatic junction. This is an aberrant pattern but reminiscent of normal embryonal lymphatic channel development. The lymphatic capillaries and vascular slits were nonreactive with LN-3 antibody, but it was positive on cell membranes in a number of spindle cells, suggesting the focal expression of Ia-antigens.

Antibodies, Monoclonal↗
PubMed1988

Cysticercosis.

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Breast Diseases↗
PubMed1987

The incidence of thyroid carcinoma in Hashimoto's thyroiditis.

The incidence of thyroid carcinoma in Hashimoto's thyroiditis has been a widely debated issue. Previous authors have reported on this topic by analyzing series of patients with Hashimoto's thyroiditis or patients with thyroid carcinoma, but not both of those populations in the same series. The population consists of a consecutive series of 800 patients operated on for thyroid nodules not associated with a radiation history. Among 161 patients with the diagnosis of thyroid carcinoma, 61 (38%) had coexistent Hashimoto's thyroiditis. In comparison, among 161 sex- and age-matched patients with colloid nodules in the same population, 18 (11%) had Hashimoto's thyroiditis. Furthermore, in the series as a whole, the incidence of Hashimoto's thyroiditis in 423 patients with colloid nodules was 10 per cent. From the perspective of the Hashimoto's thyroiditis population in the same series of 800 thyroidectomies, among 267 patients with Hashimoto's thyroiditis 61 (23%) had coexistent carcinoma. In comparison, among 267 age- and sex-matched patients with colloid nodules there were only ten coexistent carcinomas for an incidence of 4 per cent. The high incidence of carcinoma of the thyroid in Hashimoto's thyroiditis lends credence to the hypothesis that Hashimoto's thyroiditis is a predisposing factor in the development of thyroid carcinoma.

Adolescent↗
PubMed1985

Pemphigus vulgaris and malignancy.

A case of oral squamous cell carcinoma with pemphigus vulgaris is reported and the literature is reviewed. Association between the above entities has essentially been founded upon the specificity of cancer-associated antigen. To date, such an antigen has not been adequately defined, and, therefore, any causal relationship between the 2 processes on the grounds of antigenic-specificity of cancer cells remains unjustified. Hence, pemphigus and malignancy may occur as a coexisting phenomenon.

Antigens, Neoplasm↗
PubMed1985

Benign soft tissue chondromatous lesion of the hand.

Four patients with benign soft tissue chondromatous lesions of the hand have been operated on and were followed for 4 years. During this follow-up period, two patients have had recurrences that were excised, and a third patient with a recurrence is scheduled for operation.

Adult↗
PubMed1985

Correlative studies of Verruca vulgaris by H & E, PAP immunostaining, and electronmicroscopy.

Twenty-one specimens of Verruca vulgaris were used for an investigation to define what portion of the papillomatous structures seen in H & E stain will correspond to the areas of positive staining for papilloma virus antigen utilizing the peroxidase-antiperoxidase immunostaining technique. Vacuolar spaces filled with thready material and large ovoid parakeratotic cells seen in H & E stain stained positively for papilloma virus antigen. In the granular layer, viral antigens stained heavily, the nuclei of cells showing koilocytosis. Both round and irregularly shaped kerathohyaline granules did not stain positively for viral antigen stain. Eight of the 21 specimens showed marked positivity for papilloma virus antigen. Three other cases were positive in only focal sites. Of the 8 immunostained-positive selected cases used for ultrastructural studies, only 2 showed the viral particles. The study suggests that the PAP immunostaining is a more sensitive and yet less cumbersome method than electronmicroscopy for demonstration of papilloma virus.

Antigens, Viral↗
PubMed1985

Hürthle cell tumors of the thyroid gland.

The recent controversy concerning the prognosis of Hürthle cell tumors instigated the review of our experience with 34 patients treated between 1972 and 1984. On the basis of strict histopathologic criteria, 14 patients with Hürthle cell hyperplasia, 10 with Hürthle cell adenoma, and 10 with Hürthle cell carcinoma were identified. There was a 40% incidence of bilateralism in Hürthle cell carcinoma, whereas we documented bilateral disease in only one of 10 patients with Hürthle cell adenoma. Lobectomies were performed in patients with tumors considered histopathologically benign and total thyroidectomy in patients with histologically malignant lesions as well as in most patients with a history of radiation exposure. Follow-up ranges from 4 months to 12 years (mean 3.1 years). To the present time there has been no evidence of recurrence and no deaths from Hürthle cell tumors. Consequently, in our experience, Hürthle cell tumors seem to behave in a rather benign manner. Therefore it seems that the appropriate treatment for Hürthle cell adenoma and nodular hyperplasia is a lobectomy. Total thyroidectomy is reserved for patients with Hürthle cell carcinoma primarily because of the high incidence of bilateralism.

Adenoma↗
PubMed1984

Congenital adrenal tissue in the lung with adrenal cytomegaly. Case report and review of the literature.

Adrenal cytomegaly is a cellular abnormality found in the fetal and neonatal adrenal gland. It is characterized by large polyhedral cells with granular eosinophilic cytoplasm and irregular pleomorphic nuclei. A case of bilateral adrenal cytomegaly in five-day-old infant with two foci of pulmonary involvement is reported with a review of the literature. The question of whether the pulmonary lesion represents metastasis or cytomegalic change in ectopic adrenal tissue is discussed.

Adrenal Cortex↗
PubMed1983

An immunoperoxidase investigation of S-100 protein in granular cell myoblastomas: evidence for Schwann cell derivation.

Five cases of granular cell myoblastoma have been studied for detection of the neuroectodermal protein S-100. Immunoperoxidase staining on paraffin sections, using an antibody raised against calf brain S-100 protein, was utilized to demonstrate positive cytoplasmic and nuclear reactivity in all cases. Negative staining in adjacent muscle and connective tissue elements was contrasted to in situ control staining of Schwann cells in peripheral nerves and staining of Langerhans cells and melanocytes in overlying stratified epithelia. These observations are interpreted as support for possible Schwann cell origin of granular cell myoblastomas.

Adult↗
PubMed1983

Cystic hamartoma of the lung.

A patient with a rare cystic hamartoma of the lung had diagnoses of tuberculosis, bronchiectasis, pneumonia, and neoplasm during the 23 years prior to resection of the lesion. The hamartoma had vascular elements which led to intermittent hemoptysis and, finally, to gross hemorrhage into the lung.

Hamartoma↗