Alterations in the retinoblastoma pathway of cell cycle control in parathyroid tumors.

Mutations in proto-oncogenes and tumor suppressor genes have been associated with tumor development and/or progression in many neoplasms. It has been reported that parathyroid tumors have deletions affecting the retinoblastoma gene (RB), and overexpression of cyclin D1 (Cyc D1). The aim of the present study was to evaluate the alterations in the components of the pRB pathway in parathyroid adenomas and parathyroid aggressive tumors, including patterns of expression of pRB, Cyc D1, and p16/INK4A. Paired normal and tumor DNA from 6 parathyroid adenomas and 5 aggressive tumors were analyzed for loss of heterozygosity (LOH) at the RB locus. The expression of pRB, Cyc D1 and p16 was studied in 4 adenomas and 5 aggressive tumors. RB LOH was found in 1 of 6 adenomas, and in 1 of 2 informative aggressive tumors. Immunohistochemical analysis revealed undetectable pRB in 4 of 5 aggressive tumors and presence of pRB in all adenomas. Conversely, Cyc D1 expression was found in 3 of 4 aggressive tumors, but was undetectable in the adenomas. Expression of p16 was identified only in one aggressive tumor. Thus, alterations in the pRB pathway seem to prevail in the aggressive form of parathyroid neoplasms. Our results warrant further investigation of these cell cycle regulators in order to determine their potential role as tumor markers in parathyroid tumors.

[Identification of Epstein-Barr virus in nasopharyngeal carcinomas in Argentina. Its relation with p53 and the determination of proliferation indices]. / Identificación del virus Epstein-Barr en carcinomas nasofaríngeos en Argentina. Su relación con p53 y determinación de índices de proliferación.

Thirty-seven nasopharyngeal carcinomas were studied obtaining the tissue from nasopharyngeal biopsies that were formalin fixed and paraffin embedded. The patients were born in Argentina, 23 men and 14 women with a mean age of 50 years. Histologically the tumors were classified as queratinizing squamous cell carcinomas, 1 case (2%); non-queratinizing squamous cell carcinomas, 15 cases (41%) and undifferentiated carcinomas, 21 cases (57%). The proliferating index (PI) was determined using monoclonal antibodies against PCNA and Ki-67 (MIB-1), resulting in 26% for PCNA and 17% for Ki-67 while no differences were found comparing PI with histological type and cases with clinical stage III and IV. The PI was of 2% in the 3 cases with clinical stage II. Immunostains for p53 were positive in 30 out of the 37 cases with no differences between the histological types, exception made for the queratinizing carcinoma which was negative. With a cut off point of 7% in the 12 cases with follow up, two groups were found with a mean survival of 35 and 12 months, a finding that was not statistically significant. Epstein-Barr virus was detected by PCR using the paraffin embedded material in 31 out of the 37 cases: 21 were undifferentiated carcinomas and 15 non-queratinizing squamous cell carcinomas; the queratinizing squamous cell carcinoma was negative. These results, published for the first time in samples from Argentinian patients are similar to those found in areas of high and low incidence of nasopharyngeal carcinomas and can be of clinical use in determining the nasopharyngeal origin of a cervical metastatic lymph node of an unknown primary.

[Parathyroid adenoma and carcinoma. A comparative morphologic study]. / Adenomas y carcinomas de paratiroides. Un estudio morfológico comparativo.

A variety of gross, histological and cytological features were analyzed in a comparative study between adenomas and carcinomas of the parathyroid gland. The histological findings more valuable in the differential diagnosis of parathyroid carcinoma were the presence of a thick and irregular capsule infiltrated by the tumor (Fig. 1), broad and irregular intratumoral fibrous septa, and capsular or intratumoral vascular invasion (Table 1). Cytologically, the carcinomas were composed only by chief cells, with a mitotic activity higher than in adenomas, showing the presence of abnormal mitosis (Table 2, Fig 4). Characteristically all carcinomas were composed by a cellular population significantly of greater size than the one observed in adenomas.

Adenomas y carcinomas de paratiroides. Un estudio morfológico comparativo / [Parathyroid adenoma and carcinoma. A comparative morphologic study]

A variety of gross, histological and cytological features were analyzed in a comparative study between adenomas and carcinomas of the parathyroid gland. The histological findings more valuable in the differential diagnosis of parathyroid carcinoma were the presence of a thick and irregular capsule infiltrated by the tumor (Fig. 1), broad and irregular intratumoral fibrous septa, and capsular or intratumoral vascular invasion (Table 1). Cytologically, the carcinomas were composed only by chief cells, with a mitotic activity higher than in adenomas, showing the presence of abnormal mitosis (Table 2, Fig 4). Characteristically all carcinomas were composed by a cellular population significantly of greater size than the one observed in adenomas.

Adenomas y carcinomas de paratiroides. Un estudio morfológico comparativo. / [Parathyroid adenoma and carcinoma. A comparative morphologic study]

A variety of gross, histological and cytological features were analyzed in a comparative study between adenomas and carcinomas of the parathyroid gland. The histological findings more valuable in the differential diagnosis of parathyroid carcinoma were the presence of a thick and irregular capsule infiltrated by the tumor (Fig. 1), broad and irregular intratumoral fibrous septa, and capsular or intratumoral vascular invasion (Table 1). Cytologically, the carcinomas were composed only by chief cells, with a mitotic activity higher than in adenomas, showing the presence of abnormal mitosis (Table 2, Fig 4). Characteristically all carcinomas were composed by a cellular population significantly of greater size than the one observed in adenomas.

Adenomas y carcinomas de paratiroides. Un estudio morfológico comparativo. / [Parathyroid adenoma and carcinoma. A comparative morphologic study]

A variety of gross, histological and cytological features were analyzed in a comparative study between adenomas and carcinomas of the parathyroid gland. The histological findings more valuable in the differential diagnosis of parathyroid carcinoma were the presence of a thick and irregular capsule infiltrated by the tumor (Fig. 1), broad and irregular intratumoral fibrous septa, and capsular or intratumoral vascular invasion (Table 1). Cytologically, the carcinomas were composed only by chief cells, with a mitotic activity higher than in adenomas, showing the presence of abnormal mitosis (Table 2, Fig 4). Characteristically all carcinomas were composed by a cellular population significantly of greater size than the one observed in adenomas.

Estudo analitico de um novo fio sintetico em sutura gastrintestinal. / Analytic study of a new sinthetic kind in gastrointestinal suture

Com o intuito de observar um novo fio sintetico de sutura, considerado de absorcao lenta, os AA realizaram cirurgias gastrintestinais em 20 caes, divididos em lotes iguais de cinco animais cada um. Os animais de cada lote respectivamente, foram sacrificados 48 horas, cinco dias, 10 dias e 15 dias apos a cirurgia. As zonas de anastomoses foram estudadas do ponto de vista macro e microscopico, observando-se fundamentalmente a coaptacao das bordas anastomosadas, a espessura das paredes na zona de anastomose, a cicatrizacao na linha de sutura e as alteracoes histopatologicas atribuidas ao fio de sutura. A analise dos resultados obtidos permite concluir que o fio desperta minima reacao granulomatosa tipo corpo estranho, nao interferindo no processo de cicatrizacao nem produzindo reacao alergica local. Em animal algum houve ruptura das bordas anastomosadas ou ulceracao de mucosa provocada pelo fio