RESUMO
DMC1 is a meiosis-specific gene first discovered in yeast that encodes a protein with homology to RecA and may be component of recombination nodules. Yeast dmc1 mutants are defective in crossing over and synaptonemal complex (SC) formation, and arrest in late prophase of meiosis I. We have generated a null mutation in the Dmc1 gene in mice and show that homozygous mutant males and females are sterile with arrest of gametogenesis in the first meiotic prophase. Chromosomes in mutant spermatocytes fail to synapse, despite the formation of axial elements that are the precursor to the SC. The strong similarity of phenotypes in Dmc1-deficient mice and yeast suggests that meiotic mechanisms have been highly conserved through evolution.
Assuntos
Adenosina Trifosfatases , Proteínas de Ciclo Celular , Proteínas de Ligação a DNA/genética , Meiose/fisiologia , Prófase/fisiologia , Recombinases Rec A/genética , Animais , Cromossomos/fisiologia , Proteínas de Ligação a DNA/análise , Feminino , Imunofluorescência , Mutação em Linhagem Germinativa/fisiologia , Infertilidade/genética , Masculino , Camundongos , Camundongos Knockout , Proteínas Nucleares , Oócitos/química , Oócitos/fisiologia , Proteínas de Ligação a Fosfato , Proteínas Recombinantes/análise , Proteínas Recombinantes/genética , Recombinação Genética/fisiologia , Espermatozoides/química , Espermatozoides/fisiologiaRESUMO
We report a rare case of multiple lymphomatous polyposis of the gastrointestinal tract, with emphasis on the radiological, colonoscopic, and morphological findings. The underlying condition proved to be a poorly differentiated lymphocytic lymphoma. This is the first case of multiple lymphomatous polyposis in which immunologic marker studies are described and B cell origin confirmed. The different types of lymphoid polyps of the colon and the role of immunohistology are also discussed.
Assuntos
Neoplasias Gastrointestinais/imunologia , Pólipos/imunologia , Idoso , Antígenos de Superfície/imunologia , Neoplasias Gastrointestinais/patologia , Humanos , Masculino , Pólipos/patologiaRESUMO
A 52-year-old woman presented with fever, goiter, and no evidence of pain or tenderness in the thyroid. A diagnosis of silent thyroiditis was made after obtaining evidence of biochemical thyrotoxicosis, intense gallium-67 citrate thyroidal localization, and cytologic thyroiditis. Fine needle aspiration biopsy of the thyroid revealed numerous giant cells in all areas of the thyroid, typical of subacute thyroiditis. This is believed to be the first time painless thyroiditis is reported with the classic cytologic feature of painful subacute thyroiditis.
Assuntos
Granuloma de Células Gigantes/diagnóstico , Glândula Tireoide/patologia , Tireoidite/diagnóstico , Biópsia por Agulha , Feminino , Radioisótopos de Gálio , Granuloma de Células Gigantes/patologia , Humanos , Pessoa de Meia-Idade , Cintilografia , Testes de Função Tireóidea , Glândula Tireoide/diagnóstico por imagem , Tireoidite/patologiaRESUMO
In a series of 200 fine needle aspirations (FNA) of the thyroid, necrosis around the needle tract was histologically evident in 2 of 30 cases with surgical follow-up. In one case of a differentiated thyroid carcinoma, necrosis with involution of the nodule was the dominant finding. This suggests that FNA can induce necrosis and apparent clinical regression of thyroid neoplasms. We believe, however, that a positive cytologic diagnosis coupled with a clinical suspicion of neoplasm should lead to surgical intervention, despite clinical regression following FNA.
Assuntos
Biópsia por Agulha/efeitos adversos , Carcinoma/patologia , Neoplasias da Glândula Tireoide/patologia , Adulto , Feminino , Humanos , NecroseRESUMO
We report the case of a presternal ciliated cyst in a 39-year-old man. The location and histologic features of this lesion have led us to favor a primitive foregut origin for this cyst, probably via the process of embryonic sequestration and migration.
Assuntos
Cistos/patologia , Dermatopatias/patologia , Adulto , Cílios/patologia , Cistos/diagnóstico , Humanos , Masculino , Pele/patologia , Dermatopatias/diagnóstico , TóraxRESUMO
The first case of an intracranial plasma cell granuloma is presented. An associated polyclonal gammopathy was another remarkable feature. Routine and special stains of histologic sections as well as electron microscopy characterized such lesions. Immunofluorescent studies revealed a heterogeneous population of plasma cells. When the granuloma was removed, the polyclonal gammopathy resolved, and neither have recurred with eight months of follow-up. It is suggested that prior reports of meningiomas with conspicuous plasma cell-lymphocytic components may in reality be plasma cell granulomas and could be differentiated by electron microscopy.
Assuntos
Neoplasias Encefálicas/patologia , Plasmocitoma/patologia , Adolescente , Encefalopatias/patologia , Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/ultraestrutura , Diagnóstico Diferencial , Granuloma/patologia , Histiócitos/ultraestrutura , Humanos , Masculino , Meningioma/patologia , Microscopia Eletrônica , Plasmocitoma/diagnóstico por imagem , Plasmocitoma/ultraestrutura , Pseudópodes/ultraestrutura , RadiografiaRESUMO
A 20 year old black man presented with shortness of breath, hilar adenopathy, monoarticular arthritis, polydipsia and polyuria, and bilateral testicular masses. Transbronchial biopsy revealed noncaseating granulomas consistent with sarcoidosis. Subsequent work-up demonstrated hypothalamic dysfunction, and joint fluid analysis was consistent with sarcoid arthropathy. Concern over the possibility of a testicular neoplasm led to right testicular biopsy which revealed noncaseating granulomas consistent with testicular sarcoidosis. A short course of steroid therapy resulted in clinical improvement and complete resolution of the remaining left testicular mass.