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Biomedical subjects

A R Armin

Publications and source records attributed to A R Armin.

15 recordsLinked to original sources
PubMed1997

Reproducible rat model for comparing late rectal toxicity from different brachytherapy techniques.

PURPOSE: Newer brachytherapy techniques, such as pulse-simulated low dose rate (PDR) and high dose rate (HDR) offer clinical and technical advantages over the conventional continuous low dose rate (CLDR) irradiation. The impact of these techniques on late normal tissue toxicity has remained largely undefined, with mathematical modeling and limited clinical experience providing some guidelines. We sought to develop a reproducible rat model for quantifying and comparing late rectal toxicity from different brachytherapy techniques. METHODS AND MATERIALS: An intrarectal applicator has been designed and techniques have been developed to deliver clinically relevant doses of CLDR to allow comparison to PDR and HDR. Female Wistar rats are utilized. The endpoints assessed are rectal obstruction and a histological grading of late rectal injury. RESULTS: Analysis of 65 rats given either sham or single acute pulse irradiation has demonstrated the model to be reproducible and reliable in evaluating late rectal toxicity. CONCLUSIONS: The use of this rat model to compare late rectal injury from various doses, dose rates, and fractionation parameters utilized by CLDR, PDR, and HDR will provide another tool for safely implementing these techniques into the clinical setting.

Animals↗
PubMed1993

Intravascular immunoglobulin crystalloids in monoclonal cryoglubulinemia-associated dermatitis: ultrastructural findings.

A 46-year-old woman developed polyarthritis, purpuric skin rashes, nasal septal perforation and marginal furrowing of corneas in 1980. Monoclonal IgG, kappa cryoglobulinemia was found in the patient's serum. No underlying lymphoproliferative disorder has been found in ten years since her original diagnosis. In 1991, she developed palpable purpura on both lower extremities with subsequent necrosis and ulceration. A skin biopsy revealed fibrin thrombi within capillaries in the papillary dermis, and immunofluorescence studies showed IgG and light chain kappa within the fibrin thrombi. An electron microscopy study showed intravascular immunoglobulin crystalloid structures with a mean diameter of 80.3A degrees (8.03 nm), mixed with fibrin and red blood cells. The exclusive vascular location of these crystalloids may have implication in the pathogenesis of skin lesions.

Biopsy↗
PubMed1990

Giant forms of Blastomyces dermatitidis in the pulmonary lesions of blastomycosis. Potential confusion with Coccidioides immitis.

Typical yeast-phase cells of Blastomyces dermatitidis have a characteristic appearance in tissue sections. Fungal morphologic variation occurs infrequently in the lesions of blastomycosis, yet it can complicate the differential diagnosis, particularly if fresh tissue is not available for microbiologic culture. The authors report a case of pulmonary blastomycosis, confirmed by culture and direct immunofluorescence, in which some of the yeast-like cells were abnormally large. These giant yeast-like cells exceeded the size range accepted for the tissue forms of B. dermatitidis; therefore, coccidioidomycosis was considered initially in the differential diagnosis. Otherwise characteristic morphologic features of these cells, in particular multinucleation and the production of broad-based blastoconidia, helped resolve the differential diagnosis. The diagnosis can be confirmed by direct immunofluorescence or microbiologic culture.

Blastomyces↗
PubMed1990

Transitional cell carcinoma of the urinary bladder with osteoclast-type giant cells: a report of two cases and review of the literature.

We report two transitional cell carcinomas of the urinary bladder containing numerous osteoclast-type giant cells that stained for vimentin and acid phosphatase (with and without tartrate) and were negative for cytokeratin and lysozyme. One tumour, in a 65-year-old man, was composed of papillary transitional cell carcinoma, invasive poorly differentiated carcinoma with a prominent spindle cell component and numerous osteoclast-type giant cells; repeat curettage 2 months later showed no residual tumour. The second tumour occurred in a 75-year-old woman who underwent a radical cystectomy for a deeply invasive transitional cell carcinoma with a spindle and anaplastic giant cell component and areas containing numerous osteoclast-type giant cells. Osteoclast-type giant cells, which appear to be reactive, should be distinguished from the neoplastic giant cells of giant cell carcinoma.

Acid Phosphatase↗
PubMed1988

T-cell lymphoma of palatal midline. Report of 2 cases.

2 cases of unifocal T-cell lymphomas, predominantly large cell type, one restricted to the midline of the palate and the other involving the nasal cavity are reported. Monoclonal antibodies served as a useful adjunct to light microscopy in diagnosing these tumors.

Diagnosis, Differential↗
PubMed1988

Nephrogenic metaplasia of urinary tract in children: report of three cases and review of the literature.

Nephrogenic metaplasia of the urinary tract, originally thought to be a benign tumor with possible malignant potential, is commonly called nephrogenic adenoma. It predominantly affects male adults and is rarely seen in children. In this report 18 pediatric cases are reviewed and some clinical and pathologic parameters are compared with the condition in adults. Male to female ratio is reversed (3.7:1 in adults and 1:3.5 in children). Recurrences are more common and are more frequently multiple in the pediatric age group. Although no malignant transformation has been reported, prolonged follow-up is recommended since the natural history of this lesion is still uncertain.

Child, Preschool↗
PubMed1987

Unusual extramedullary relapse of acute lymphoblastic leukemia in a bone marrow transplant patient.

An unusual form of relapse of acute lymphoblastic leukemia is described in a woman who developed a solitary large focal mass of lymphoblasts in her liver and an isolated polypoid lymphoblastic mass in her uterus after bone marrow transplantation, despite continued marrow remission. Extramedullary visceral leukemic relapse in the form of such discreet focal masses is highly unusual and to our knowledge has not been described in this setting. Awareness and recognition of atypical forms of relapse are important since such a diagnosis carries critical therapeutic and prognostic implications.

Adult↗
PubMed1986

Parathyroid peliosis: report of a case and review of the literature.

Peliosis most commonly affects the liver and spleen and has been associated with exogenous and endogenous steroid hormones, particularly of the anabolic type. The finding of peliosis of the parathyroid glands, as well as of the liver, in an infant with adrenogenital syndrome indicates that other organs may be affected.

Adrenal Glands↗
PubMed1985

Tungiasis.

Explore the source record for details and available documents.

Aged↗
PubMed1985

Fibrosing peritonitis in a drug abuser.

We report a case of fatal fibrosing peritonitis in a 28-year-old drug abuser. The extensive fibrosis, which was limited to the abdominal cavity, contained birefringent material. Silica was identified by spectrophotometric analysis. Silica is a component of talc (magnesium silicate) used as a drug filler. Relatively small amounts are known to induce fibrosis. The manner of introduction of this material into the peritoneal cavity is hypothetical and includes accidental direct peritoneal contamination during subcutaneous injections, a method used by drug abusers.

Adult↗
PubMedDate not supplied

MR imaging of myositis ossificans: variable patterns at different stages.

Five patients with a palpable mass at presentation underwent magnetic resonance (MR) imaging. The final diagnosis was myositis ossificans (MO). MR imaging features, particularly after injection of gadopentetate dimeglumine, mimicked those of an inflammatory mass or neoplasm. The lesions were excised in three patients, and the images were correlated with histologic findings. Three different appearances were noted on MR images, corresponding to the stages of maturation of MO. Two cases involved early-stage lesions, and T1-weighted MR images showed a mass with homogeneous intermediate signal intensity. Both lesions showed rim enhancement after contrast agent injection and high signal intensity on T2-weighted images. Pathologic specimens demonstrated stroma with masses of spindle cells in which osteoid production was interspersed. The enhanced rim of the lesion mimicked the expected MR appearance of an abscess or necrotic tumor. Areas of enhancement in adjacent muscle were also seen on postcontrast T1-weighted images. Intermediate-stage MO was present in one case; there was evidence of a thin rim of calcification on plain radiographs and fatty changes in the lesion on T1-weighted images, corresponding with histologic findings. One case of a mature lesion showed a considerable degree of peripheral calcification both on MR images and at histology. MR imaging is nonspecific in the diagnosis of early-stage MO.

Abscess↗
PubMedDate not supplied

Giant cell tumor of the tendon sheath in the ankle: MRI with pathologic correlation.

We report a case of Giant cell tumor of the tendon sheath involving the ankle, wherein spin-echo (T1- and T2-weighted), gradient-echo, and dynamic contrast-enhanced sequences were performed, and the tumor was noted to be very vascular. To the best of our knowledge, the use of gradient-echo sequences and the pattern of enhancement by time-intensity curves has not been reported earlier.

Adult↗
PubMedDate not supplied

Imaging features of splenic epidermoid cyst with pathologic correlation.

The spleen can be involved in a variety of cystic lesions ranging from cystic neoplasms and parasitic cysts to "true" and "false" cysts. Epidermoid splenic cyst is a rare true cyst that is developmental in origin. We present two young patients with such a cyst and illustrate their features on ultrasound, CT, and MRI with pathologic correlation.

Adult↗