Histological study of megakaryocytogenesis and thrombocytogenesis in the guinea pig bone marrow with reference to the role of adipocytes

Blood platelets play a pivotal role in hemostasis and participate directly in thrombosis and atherosclerosis. The aim of the study was to investigate the steps of platelet production, the morphological changes that occur during proplatelet production, the cytoskeletal mechanics that drive these transformations, and the possible role of stromal cells in platelet formation. Red bone marrow fragments were harvested from ten adult male guinea pigs. Toluidine blue-stained semithin sections were prepared for light microscopic examination, and ultrathin sections were examined by transmission electron microscope. In the semithin sections of the bone marrow, nearly half of the area contained hematopoietic cells, whereas the remainder was occupied by adipocytes that showed unusual bridging connections between them. In addition, the megakaryocytic lineage cells assumed a unique close association with the neighboring adipocytes. Under transmission electron microscope, the surface of the immature megakaryocytes was characteristically smooth, whereas mature megakaryocytes developed characteristic proplatelets in the form of coarse surface cytoplasmic processes that bulged to the outside and detached as preplatelets. Granules and membranes associated with microtubules were translocated from the base of proplatelets to appear in their cytoplasm, and the invaginated membrane system became extensive in the mature megakaryocytes. Sometimes, these cells extended large proplatelets through the attenuated sinusoidal walls, where they discharged preplatelets that further fragmented into platelets. The formation of proplatelets and the elaboration of granules into the newly formed preplatelets and platelets were largely dependent on the efficiency of microtubular cytoskeletal elements. Marrow stromal cells, especially adipocytes, might be involved in megakaryocytic lineage development

histological study on the effect of noise on the adrenal cortex of adult male guinea pigs and the possible role of combined vitamin [A, C, and E] supplementation

Noise exposure is considered a stressful factor that causes changes in many organs, including the endocrine system. Timing of intervention by antioxidants obviously has a key role in the success of the therapeutic regimen. The aim of the study was to investigate the effect of noise exposure on the histological structure of the adrenal cortex in adult male guinea pigs and evaluate the role of postnoise treatment with vitamins A, C, and E. Thirty adult male guinea pigs were divided equally into three groups. Group I [the control group]; group II [the experimental group], which was exposed to noise 4 h/day for 30 days; and group III, which was exposed to noise in the same manner as group II and then administered vitamins A, C, and E once daily for 5 successive days, starting 1 day after noise exposure. Specimens of the adrenal cortex were processed for study by light [H and E stain] and electron microscopy. Morphometric study was also performed. The adrenal cortex of the noise-exposed group [group II] showed loss of architecture of the zona glomerulosa and fasciculata with cellular infiltration. In addition, zona fasciculata cells showed marked cytoplasmic vacuolation, whereas zona reticularis cells appeared with condensed nuclei and congested blood sinusoids. Ultrastructurally, zona glomerulosa and fasciculata cells revealed swollen mitochondria, dilated cisternae of smooth endoplasmic reticulum, and a few lipid droplets. Animals treated with combined vitamins [group III] revealed restoration of the normal adrenocortical structure, whereas zona reticularis showed increased proliferative activity. Morphometric study revealed a significant increase in the mean thickness of the cortex and surface area of both zona glomerulosa and fasciculata of the exposed animals, whereas group III revealed nonsignificant difference from the control. Exposure to noise caused histological alterations in the structure of the adrenal cortex. Postnoise treatment with vitamins A, C, and E could markedly reduce these alterations

Ocorrência de siphonaptera em preá cavia aperea exerleben, 1777 (rodentia: caviidae) no Rio Grande do Sul, Brasil / Occurrence of siphonaptera in cavia aperea exerleben, 1777 (rodentia: caviidae) in the state of Rio Grande do Sul, southern Brazil

Due to limited knowledge of Siphonaptera fauna of the Cavia aperea (Brazilian guinea pig) in the State of Rio Grande do Sul, 43 specimens were examined. Six percent of the Brazilian guinea pigs were parasitized with Siphonaptera, which were identified as Polygenis (Neopolygenis) atopus and Polygenis (Polygenis) axius proximus (Rhopalopsyllidae), both with 2.3% of prevalence. P. (Neopolygenis) atopus and P. (Polygenis) axius proximus are reported for the first time on C. aperea in the State of Rio Grande do Sul, Southern Brazil.

Estereología comparativa entre el bazo del cuye (Cavia porcellus) y la rata (Rattus novergicus, Sprague Dawley) / Comparative stereology between the spleen of the Guinea pig (Cavia porcellus) and the rat (Rattus novergicus, Sprague Dawley)

El bazo es el órgano linfático periférico más grande del organismo y conocer sus aspectos morfológicos cuantitativos es importante para determinar posibles patologías. El objetivo del estudio fue determinar en dos especies: cuye (Cavia porcellus) y rata (Rattus novergicus Sprague Dawley), las características estereológicas del bazo, para obtener patrones de normalidad cuantitativos, los que servirán de base para futuros estudios morfofuncionales. Se utilizaron 5 bazos de cada especie, clínicamente sanos, obtenidos del Bioterio de la Universidad de La Frontera, Temuco, Chile. Los bazos fueron disecados y fijados en formalina tamponada al 10 por ciento y se determinó el volumen de éstos por el método de Scherle. Se obtuvieron 5 trozos por medio de Orientador los que fueron incluidos en paraplast. De cada trozo se obtuvieron 5 cortes histológicos de 3 micrones m de grosor y separados 200 micrones m entre sí, los cuales fueron teñidos con H-E. El porcentaje de pulpa roja, pulpa blanca y zona marginal en el bazo del cuye fue: 65,14 por ciento, 21,96 por ciento y 12,67 por ciento, respectivamente, y en la rata 53,9 por ciento de pulpa roja, 25,75 por ciento pulpa blanca y 15,87 por ciento de zona marginal. El número total de folículos fue 8,33 x 10² y 5,73x 10² para el cuye y la rata, respectivamente. Los resultados concuerdan con los obtenidos por otros autores, pudiéndose señalar un patrón cuantitativo del porcentaje de los compartimentos esplénicos de normalidad, que se podría considerar para futuros estudios morfo-funcionales.

The spleen is the largest peripheral lymphoid organ of the body so it is essential to know their morphological quantitative aspects in order to identify potential abnormalities. The aim of this study was to determine the parameters stereological spleen in normal two species commonly used in research such as the guinea pig and rat, to obtain quantitative patterns of normality, which will serve as a basis for future studies morphofunctional. 5 spleens were used for each species (Cavia porcellus and Rattus novergicus, Sprague Dawley) obtained from biotery the Universidad de La Frontera, Temuco, Chile. The spleens were dissected and fixed in formalin buffered to 10 percent and the volume is determined by the of Scherle method. 5 pieces were obtained through Orientator and these were included in paraplast. Each piece was performed histological cuts of 3 mm thick and separated 200 µm each other, which were stained with H-E. The percentage of redpulp, whitepulp and marginal zone in the Guinea pig was: 65.14 percent, 21.96 percent and 12.67 percent respectively, and in the rat 53.9 percent pulpred, 25.75 percent whitepulp and 15.87 percent of marginal zone. The total number of follicles was 8.33 x 10²follicles and 5.73 x 10² follicles for the Guinea pig and rat, respectively. The results are consistent with those obtained by other authors might identify a pattern of quantitative percentage of splenic compartments of normality that could be considered for future studies morpho-functional.

Potency assay of diphtheria antitoxin in vero cell micro-cultures

Se establecieron condiciones para llevar a cabo la titulación de antitoxina diftérica en células Vero (TCC), y comparar los resultados con la prueba intradérmica (TID) tradicionalmente empleada en todo el mundo para determinación de potencia de toxoide diftérico y de antitoxina de uso terapéutico. Los resultados de titulaciones en pruebas intradérmicas y en cultivos celulares mostraron gran repetibilidad y detectabilidad a concentraciones muy bajas de toxina en la prueba de cultivos celulares, así como una correlación satisfactoria en la titulación de antitoxinas preparadas por inmunización con Patrón Internacional de OMS y con antitoxina de uso terapéutico, pero en los sueros de cobayo se observó un título aproximadamente 10 veces menor al de la prueba intradérmica. Se discuten las posibles causas de estas diferencias de títulos. Esta prueba se podrá adoptar en la forma propuesta para determinar potencia de antitoxina diftérica. En la prueba de potencia del toxoide diftérico, se podría usar si el límite de título en los cobayos se ajusta a 0.2 UIAD en lugar de 2.0 UIAD/ml que se emplea actualmente, considerando la equivalencia obtenida entre las dos pruebas y tomando en cuenta una relación 1:10 entre las pruebas TCC y TID