Energy substrate used by workers of leaf-cutting ants during nest excavation

Energy substrate used by workers of leaf-cutting ants during nest excavation. In this study we aimed to ascertain whether leaf-cutting ant workers lose body reserves (fat or sugars) as a function of nest excavation. For each treatment, we isolated 10 workers of Atta sexdens into two experimental groups, Control (C- without excavation) and Soil (S- with excavation), which were kept for different time intervals (0, 24, 48 or 72 hours), totaling 700 tested workers. We then determined the concentration of soluble carbohydrates and total lipid content in them. The total carbohydrates were determined colorimetrically, based on the reaction between carbohydrates and sulfuric acid-phenol. For determination of lipids, the insects were immersed in organic solvent until they reached a constant weight. Our results showed that carbohydrates are consumed during nest excavation activities. In the experimental groups S24, S48 and S72, there was an average reduction of 5.82 (20.42%), 14.31 (44.96%) and 13.27 (43.96%) µ.mg-1 in soluble sugar when compared with the experimental groups that did not excavate. Furthermore, the lipids were not used during this activity. With respect to dry mass of the workers, their values were C0 = 8%, C24 = 10.4%, C48 = 9.2%, C72 = 10%, S24 = 9.2%, S48 = 8.7% and S72 = 8.5%. Our results show experimentally that the source of energy for nest excavation is carbohydrates, whereas lipids are conserved for other activities.

Aloetismo em Acromyrmex subterraneus brunneus Forel (Hymenoptera, Formicidae), durante o forrageamento, cultivo do jardim de fungo e devolução dos materiais forrageados / Alloethism in Acromyrmex subterraneus brunneus Forel (Hymenoptera, Formicidae), during foraging, fungus-garden cultivation and devolution of foraged materials

As formigas cortadeiras apresentam uma sofisticada divisão de trabalho durante o forrageamento, cultivo do jardim de fungo e devolução dos materiais forrageados. Materiais com diferentes graus de hidratação e dureza (esponja floral, isopor, plástico e argila) foram oferecidos a duas colônias de laboratório de Acromyrmex subterraneus brunneus Forel, 1911. As diferentes categorias de tamanho de operárias foram observadas durante a execução de 14 subtarefas. Probabilidade relativa de desempenho e as curvas aloéticas foram usadas para verificar a flexibilidade comportamental e os padrões comportamentais estereotipados das operárias. Os padrões comportamentais possibilitaram estabelecer papeis dentro de prováveis subcastas.

Clinicopathologic evaluation of thyroid tumors through p53 protein accumulation and proliferative activity measured using Ki-67 and PCNA monoclonal antibodies

Thyroid neoplasms frequently present difficulties in the diagnostic and prognostic evaluation due to the poor relation between morphology and tumor behavior. It is particularly important to define parameters to evaluate the potential of aggressiveness of such neoplasias with ancillary techniques in order to improve the clinical management of the patients with thyroid tumors. The potential of three markers - p53, Ki-67 and PCNA - in adenocarcinomas of the thyroid was evaluated and the relation of these markers to the prognostic behavior of the tumors were analyzed in a retrospective study. Seventy-seven cases of patients with neoplasms of the thyroid, submitted to thyroid surgery by the same surgeon (RSC), belonging to the team, were studied. Histological sections of the samples were submitted to immunohistochemical reactions with anti-p53 (cione D07), anti-Ki-67 (clone MIB1) and anti-PCNA (clone PC 10) monoclonal antibodies. The positive demarcations were counted in 200 cells of selected areas. The results were correlated with clinical and histopathologic parameters, selected among the survival distributions for each category of a same variable, through the Cox-Mantel test. There were 14 p53 positive cases, 17 Ki-67 positive and ali cases were PCNA positive. Although Ki-67 is theoretically present in ali the phases of cell division, it was not possible to identify it in ali cases; PCNA, was shown as an identification marker with expressive sensitivity. The immunohistochemical study showed ali follicular adenocarcinomas with PCNA positive immunoreaction, 11 (36,6 percent) Ki-67 positive and 8 (26,6 percent) p53 positive; 30 papillary tumors were PCNA positive, 5 (16,6 percent) Ki-67 positive, and 6 (20 percent) p53 positive. Medullary and Hürthle cell adenocarcinomas showed only PCNA positive immunoreaction, 3 and 2 cases respectively. Regarding the undifferentiated adenocarcinomas, 5 specimens presented PCNA positive immunoreaction, 1 was Ki-67 positive, 3 were p53 positive. PCNA monoclonal antibody showed a positive correlation with patient age and histologic type (p=0.005 and p= 0.032 respectively).

Miotomia transversal como recurso auxiliar nas anastomoses esofagicas: estudo experimental em caes / Transverse miotomy as an auxiliary procedure in the esophageral anastomosis: an experimental study in dogs

Os autores operaram 24 caes de ambos os sexos, submetendo-os a esofagectomia cervical parcial com anastomose primaria em plano unico e miotomias transversais totais a montante e a jusante da anastomose. Os animais foram divididos em dois grupos: I e II. Os animais do grupo I foram observados por um periodo medio de 63 dias. Os sobreviventes foram submetidos ao estudo da circulaçao pelo metodo da fluoresceina, e em cinco animais de cada grupo, apos o sacrificio, procedeu-se o estudo da circulaçao esofagica pelo metodo da diafanizaçao de Spalteholtz. Observou-se ainda que a circulaçao fazia-se pela rede vascular submucosa e por vasos neoformados originarios do ramo esofagico das arterias tireoidianas cranial e caudal, e de outras estruturas anatomicas vizinhas. Concluiram que as miotomias justanastomoticas nao interferem com a circulaçao adjacente

Avaliaçäo do DNA pela citofotometria nos tumores papiliferos da tireoide / DNA evaluation by cytophotometry in papillary thyroid tumour

A avaliacao quantitativa do DNA tem sido realizada em varios tumores malignos, inclusive da tireoide. Tem sido encontrado aumento da percentagem de aneuploidia em tumores de mau prognostico, enquanto que os carcinomas com distribuicao do DNA euploide seguem um curso benigno. Neste trabalho estudamos o teor do DNA nuclear de vinte casos de carcinomas papiliferos propriamente dito e dezenove de variantes papilifero. O metodo utilizado foi da citofotometria de lamina. Os histogramas foram classificados de acordo com Auer. A aneuploidia (tipo IV) esteve presente em 35,90% de todos os casos estudados.Entre os dois grupos de carcinoma papilifero nao foi observada diferenca significativa na distribuicao dos valores de DNA. Embora a literatura mostre que as variantes papiliferas tem um prognostico pior, nao pudemos comprovar analisando o conteudo de DNA nuclear. Concluimos que a citofotometria para avaliacao do DNA pode fornecer dados que permitem melhor estabelecer o prognostico de um determinado paciente, isoladamente

Funçäo tireoidian e produçäo de AMP cíclico em nódulos autônomos da tiróide / Thyroid function and cyclic AMP production in autonomous thyroid nodules

Foram estudadas cinco pacientes eutiroidianas portadores de nódulos autônomos à cintilografia tireiodiana, com diàmetro superio a 3cm e näo supressíveis pela administraçäo de T, (100µg/dia durante 10 dias). Quatro das pacientes apresentaram exames laboratoriais (T4 livre, T3 TSH basal e captaçäo de 131I em 24h) normais. Fatias de tecido tireoidiano adenomatoso e paranodular obtidas pela tiroidectomia foram incubadas com concentraçöes crescentes de TSH e na presença ou näo de iodeto de potássio (KI)ou triiodotironina (T3). O incremento da produçäo de AMP cíclico (cAMP) provocado pelo TSH no tecido adenomatoso foi igual ao encontrado do tecido adjacente paranodular. No tecido paranodular a adiçäo de T3 ou KI inibiu significativamente a produçäo de cAMP, enquanto que, no tecido adenomatoso, a açäo inibitória ocorreu apenas com KI. Estes resultados sugerem: 1) a inibiçäo da secreçäo pode ocorrer na presença de níveis hormonais tiroidianos circulantes normais; 2) nâo há evidência de sensibilidade aumentada ao TSH no tecido autônomo quando avaliada pela produçäo de cAMP; 3) a ausência inibitória do T, na resposta do TSH no tecido nodular sugere alteraçäo celular ao nível de outros reguladores da geraçäo de cAMP.