Morphological Analysis of Reticuloendothelial System in Capuchin Monkeys (Sapajus spp.) after Meso-2,3-Dimercaptosuccinic Acid (DMSA) Coated Magnetic Nanoparticles Administration.

Magnetic nanoparticles can be used for numerous in vitro and in vivo applications. However, since uptake by the reticuloendothelial system represents an obstacle for the achievement of nanoparticle diagnostic and therapeutic goals, the aim of the present study was to evaluate the uptake of dimercaptosuccinic acid coated magnetic nanoparticles by reticuloendothelial system phagocytic cells present in lymph nodes, spleen, and liver tissue and how the presence of these particles could have an impact on the morphology of these organs in capuchin monkeys (Sapajus spp.). Animals were intravenously injected with dimercaptosuccinic acid coated magnetic nanoparticles and euthanized 12 hours and 90 days post-injection. Organs were processed by transmission electron microscopy and histological techniques. Samples of spleen and lymph nodes showed no morphological changes. Nevertheless, liver samples collected 90 days post-administration showed slight morphological alteration in space of Disse. Moreover, morphometrical analysis of hepatic mitochondria was performed, suggesting a clear positive correlation between mitochondrial area and dimercaptosuccinic acid coated magnetic nanoparticles administration time. The present results are directly relevant to current safety considerations in clinical diagnostic and therapeutic uses of magnetic nanoparticles.

Differential elemental distribution of retained particles along the respiratory tract.

CONTEXT: Prolonged exposure to ambient particles is associated with premature mortality due to cardio-respiratory diseases and lung cancer. The size and composition of these particles determine their toxicity, which is aggravated by their long-term retention in the lungs. OBJECTIVE: To compare the elemental profile of particles retained along the bronchial tree and lymph nodes by combining laser capture microdissection (LCM) and elemental composition analysis through energy dispersive x-ray (EDX) and scanning electron microscopy (SEM). MATERIAL AND METHODS: Twenty-four right lung middle lobes from autopsied cases were obtained from two cities with different pollution backgrounds. Lung samples were collected from three distinct sites within the lung at the time of autopsy: peribronchial tissue, peripheral parenchyma and hilar lymph nodes. Areas of potentially increased particle deposition were microdissected using LCM and analyzed for elemental composition through EDX "allied" with SEM. RESULTS: Elemental analyses of the particles retained along the bronchial tree showed two groups of distribution: peribronchiolar or lymph node deposition. The elemental profile of peribronchial areas were significantly different between the two cities and were better discriminators of past air pollution exposure. CONCLUSION: Our data suggest that particle uptake varies along the bronchial tree and human lung tissue retains particles indicative of regional air pollution background.

Preservation of Haemal Nodes Fixed by Means of Two Different Aldehyde Fixatives: a Scanning Electron Microscopic Study / Preservación de Nodos Linfáticos Hemales Fijados por Dos Fijadores de Aldehído Diferentes: un Estudio de Microscopía Electrónica de Barrido

Glutaraldehyde is the fixative most commonly used in electron microscope studies of biological tissues, however it is often necessary to use samples which were not fixed in this fixative, even with the usual uncertainty of the results that may be obtained. The fixation is the more delicate step of the sample processing. Therefore in this work, the quality of preservation of haemal nodes fixed with two classic aldehyde fixatives: formaldehyde and glutaraldehyde we have compared under the scanning electron microscope. Our results showed that both fixatives were successful in preserving the morphology of haemal nodes components; however glutaraldehyde conferred satisfactory results mainly in the preservation of parenchymal cells, whereas formaldehyde was better for preservation of stromal fibres.

El glutaraldehido es el fijador que se utiliza con más frecuencia en estudios en los tejidos biológicos a través microscopía electrónica. Sin embargo, a menudo es necesario utilizar muestras que no han sido fijadas con este fijador, aún con la incertidumbre de los resultados que se puedan obtener. La fijación es el paso más importante en el procesamiento de los tejidos. Por lo anterior, hemos efectuado este estudio comparando la calidad de conservación de nodos linfáticos hemales fijados con formaldehido y glutaraldehido. Los resultados muestran que ambos fijadores conservaron adecuadamente la morfología de los componentes de los nodos linfáticos hemales, sin embargo, el glutaraldehido conservó en mejores condiciones, principalmente, las células del parénquima, pero el formaldehido conservó mejor las fibras del estroma en nodos linfáticos.

Erythropoiesis and erythrophagocytosis in bovine haemal nodes / Eritropoyesis y eritrofagocitosis en nodos linfáticos hemales de bovino

Whether bovine haemal nodes are involved in turnover of red blood cells has been a subject of some controversy In this study, fluorescent and conventional optical microscopy of conventionally or immunohistochemically stained node sections, together with transmission electron microscopy, showed the presence of erythrocyte precursors and megakaryocytes, and evidence of active involvement in the destruction and replacement of old or degenerate red cells and the platelets.

Si nodos linfáticos hemales bovinos están involucrados en la cantidad de volumen de glóbulos rojos ha sido objeto de cierta controversia. En este estudio, secciones de nodos linfáticos teñidas convencionalmente o inmunohistoquimicamente fueron analizadas con microscopía óptica fluorescente y convencional, junto con microscopio electrónico de transmisión, los que revelaron la presencia de precursores eritrocíticos y megacariocitos, y la evidencia de participación activa en la destrucción y sustitución de glóbulos rojos viejos o degenerados y plaquetas.

Biopsia ecoguiada de la axila y disección axilar mínima ganglionar: como alternativas para la identificación de metástasis en el ganglio centinela en cáncer de mama / Axillary ecoguide biopsy and minimal axillary nodes disection: as an alternative for identification of metastasis in sentinel nodes in breast cancer

Investigar la presencia de metástasis de los ganglios centinela y como alternativa a los métodos tradicionales (Radiofármaco Tc 99 y colorante). En 128 pacientes con diagnóstico de cáncer de mama se evaluaron la presencia de ganglios linfáticos axilares. Se utilizó una biopsia ecoguiada de los ganglios de la axila, cuando son vistos al ultrasonido, una disección axilar mínima ganglionar. Se compararon los resultados con la disección axilar estándar. El diagnóstico histológico del tumor primario se realizó por biopsia ecoguiada o por estereotaxia. La biopsia ecoguiada de la axila identificó 22 por ciento de metástasis en ganglios centinelas. La disección axilar mínima ganglionar se practicó en el 55 por ciento de las 66 pacientes operadas, fue capaz de identificar ganglios centinelas con metástasis en el 37 por ciento. El ultrasonido es capaz de identificar un 36 por ciento de lesiones subclínicas. La muestra se realizó fundamentalmente en tumores T1 y T2, y cuando la biopsia ecoguiada de la axila identifica metástasis axilares, identifica pacientes de riesgo elevado, independientemente del tamaño de su tumor, que pudieran beneficiarse de un tratamiento de inducción. El cirujano mastólogo debería utilizar el ultrasonido mamario para la evaluación integral de las pacientes. La biopsia ecoguiada de la axila y la disección axilar mínima ganglionar pudieran ser métodos para la determinación de ganglios centinela, en forma más accesible a hospitales públicos, evitando la morbilidad de la disección axilar completa en tumores pequeños con ganglios negativos

Venezuelan equine encephalitis virus infection of spiny rats.

Enzootic strains of Venezuelan equine encephalitis virus (VEEV) circulate in forested habitats of Mexico, Central, and South America, and spiny rats (Proechimys spp.) are believed to be the principal reservoir hosts in several foci. To better understand the host-pathogen interactions and resistance to disease characteristic of many reservoir hosts, we performed experimental infections of F1 progeny from Proechimys chrysaeolus collected at a Colombian enzootic VEEV focus using sympatric and allopatric virus strains. All animals became viremic with a mean peak titer of 3.3 log10 PFU/mL, and all seroconverted with antibody titers from 1:20 to 1:640, which persisted up to 15 months. No signs of disease were observed, including after intracerebral injections. The lack of detectable disease and limited histopathologic lesions in these animals contrast dramatically with the severe disease and histopathologic findings observed in other laboratory rodents and humans, and support their role as reservoir hosts with a long-term coevolutionary relationship to VEEV.

Emperipolesis in a case of B-cell lymphoma: a rare phenomenon outside of Rosai-Dorfman disease.

We describe a case of a diffuse large B-cell lymphoma with extensive emperipolesis phenomenon. Light microscopy revealed numerous CD68-positive/S-100-negative histiocytes containing viable neoplastic hematopoietic cells in their cytoplasm. Electron microscopy confirmed these findings. In this case, there was no evidence of Rosai-Dorfman disease either clinically or histologically. This report emphasizes that emperipolesis is not restricted to Rosai-Dorfman disease and can be found in other conditions including non-Hodgkin lymphomas.

Structural aberrations of chromosomes 17 and 12 in chronic B-cell disorders.

OBJECTIVES: Genomic aberrations can now be identified in approximately 80% of chronic lymphocytic leukemia, small lymphocytic lymphoma (CLL/SLL) patients. In the present study, four new structural changes involving chromosomes 17 and 12 in CLL/SLL patients are described. METHODS: Five patients were selected for inclusion in the present report among a total of 92 cases with diagnosis of CLL/SLL. Cytogenetic studies and fluorescence in situ hybridization (FISH) analysis to detect some of the most frequent cryptic aberrations occurring in CLL/SLL patients were performed. Clinical studies are also described. RESULTS: Four cases showed structural rearrangements of chromosome 17. A psu dic(17;2)(p11.2;p21), leading to p53 deletion, was observed in a patient who developed a mixed cellularity Hodgkin's disease coexisting with the CLL/SLL in the same lymph node. Epstein Barr virus was detected in the Reed-Sternberg cells. Two cases had a balanced translocation t(2;17)(p21;q23). Both patients showed trisomy 12 and clonal evolution and one of them also had 11q deletion. In addition, a der(17)t(12;17)(q13;q25) as a part of a complex karyotype, and a complex translocation t(5;12;19) (q15;p11;q13) were also found. Four patients had an adverse clinical outcome and died because of disease progression. CONCLUSIONS: Four unreported nonrandom chromosome aberrations in CLL/SLL patients, one of them who might represent a new recurrent abnormality, are described. These uncommon abnormalities, mostly associated with evolving disease, may have implications for the understanding of genetic events associated with disease progression in this pathology.

Mast cell types and cell-to-cell interactions in lymph nodes of the opossum Didelphis albiventris.

Previous light-microscopic studies have shown a unique population of mast cells in lymphatic sinuses of lymph nodes located in the head, neck, axillary fossa and inguinal region of the opossum. In the present work, scanning and transmission electron-microscopic studies in the opossum mandibular and superficial axillary lymph nodes have strengthened the differences between connective-tissue mast cells (CTMC) and the lymphatic-sinus mast cells (LSMC). Further, close appositions of mast cells to other cells were described. At the nodal capsule, CTMC contacted fibroblast and granulocytes. In the lymphatic sinuses a few CTMC contacted LSMC, macrophages and reticular cells. The LSMC contacted macrophages, reticular cells and other LSMC. A few LSMC could be located in the medullary cord in close contact with plasma cells or other lymphoid cells, keeping the same ultrastructural features of those found in the lymphatic sinuses. An important new finding was provided by light-microscopic studies in nine abdominal lymph nodes. Most of them (para-aortic, common iliac, cardial, cecocolic and those of the body and tail of the pancreas) displayed numerous LSMC with the same distribution and histological features described herein. However, the mesenteric, pyloric and head-of-pancreas lymph nodes were virtually devoid of LSMC. Instead, their mast cells occurred mainly at the medullary cords and were very similar to the CTMC. Ultrastructural studies at the mesenteric lymph nodes confirmed the CTMC character of the mast cells located at both medullary cords and sinuses, and disclosed interactions with macrophages and lymphoid cells.

[A viral infection in the neck glandula of larvae of Dione junio (Lepidoptera: Nymphalidae)]. / Una infección viral en la glándula cervical de larvas de Dione junio (Lepidoptera: Nymphalidae).

Lepidopteran larvae may be attacked by different viruses, many of which belong to the Baculoviridae family. Whilst studying the ultrastructure of the neck gland in Dione junio larvae we found that in later instars the larvae showed symptoms of attack by two types of virus. The glands were prepared for optical and electron microscopy using sodium cacodylate buffer and standard procedures (0.1M, pH 7.2). The neck gland is composed of two oval internal sacks which communicate with the exterior via an extracellular channel. Each sack contains, in its external region, cells with large, irregular nuclei and a dense cytoplasm containing numerous small mitochondria. In infected larvae, the tissues are damaged and the nuclear polyhedrosis virus can be observed in several of the nuclei. In the cytoplasm another "rickettsia type" virus, may be observed. The pathogenic viruses present in D. junio larvae could be studied as potential biological controls of this pest.

Una infección viral en la glándula cervical de larvas de Dione junio (Lepidoptera: Nymphalidae) / A viral infection in the neck glandula of larvae of Dione junio (Lepidoptera: Nymphalidae)

Lepidopteran larvae may be attacked by different viruses, many of which belong to the Baculoviridae family. Whilst studying the ultrastructure of the neck gland in Dione junio larvae we found that in later instars the larvae showed symptoms of attack by two types of virus. The glands were prepared for optical and electron microscopy using sodium cacodylate buffer and standard procedures (0.1M, pH 7.2). The neck gland is composed of two oval internal sacks which communicate with the exterior via an extracellular channel. Each sack contains, in its external region, cells with large, irregular nuclei and a dense cytoplasm containing numerous small mitochondria. In infected larvae, the tissues are damaged and the nuclear polyhedrosis virus can be observed in several of the nuclei. In the cytoplasm another "rickettsia type" virus, may be observed. The pathogenic viruses present in D. junio larvae could be studied as potential biological controls of this pest.

[Follicular dendritic cell sarcoma in a lymph node]. / Sarcoma de celulas foliculares dendriticas en ganglio linfatico.

We report the case of a 39 years old man who presented with a rapidly enlarging, painless mass in his left side of the neck. The mass was excised and turned out to be a lymph node. Histologically, it showed a proliferation of oval to spindle cells growing in sheets and fascicles, occasionally forming a storiform pattern. Tumor cells showed large nuclei, dispersed chromatin and small evident nucleoli. Neoplastic cells were positive for immunohistochemical markers vimentin, CD 68, CD 21, CD 35 and R 4/23. Ultrastructural examination showed long cytoplasmatic processes joined by desmosomes. The patient was treated with local radiotherapy and is alive and well 18 months after the excision. Follicular dendritic cell sarcoma is a very unusual tumor that merits wider recognition.

Sarcoma de celulas foliculares dentriticas en ganglio linfatico / Follicular dentritic cell sarcoma in a lymph node

Se presenta el caso de un paciente se sexo masculino de 39 años de edad, asintomático,que consulta por una masa laterocervical izquierda de rápido crecimiento. Se reseca el tumor correspondiendo a una adenopatía que media 5 x 4 cm. Histológicamente se observaba un borramiento difuso de la arquitectura ganglionar por una proliferación de células fusiformes y ovales dispuetas en fascículos y nidos con sectores de patrón estoriforme. Las células presentaban núcleo alargado, cromatina laxa, y nucléolo evidente observándoses algumas mitosis. El estudo inmunohistoquímico reveló positividad en las células tumorales con vimentina, CD 68 y los marcadores de células foliculares dendríticas CD 21, CD 35 y R 4/23. Se realizó microscopia electrónica confirmándose la presencia de prolongaciones citoplasmáticas con abundantes desmosomas. El paciente fue tratado con radioterapia local y 18 meses luego de la operación se halla sin evidencias de enfermedad. Creemos que con el mejor conocimiento de la entidad, la misma será más fácilmente y, tal vez, más frecuentemente diagnosticada.

Sarcoma de celulas foliculares dentriticas en ganglio linfatico / Follicular dentritic cell sarcoma in a lymph node

Se presenta el caso de un paciente se sexo masculino de 39 años de edad, asintomático,que consulta por una masa laterocervical izquierda de rápido crecimiento. Se reseca el tumor correspondiendo a una adenopatía que media 5 x 4 cm. Histológicamente se observaba un borramiento difuso de la arquitectura ganglionar por una proliferación de células fusiformes y ovales dispuetas en fascículos y nidos con sectores de patrón estoriforme. Las células presentaban núcleo alargado, cromatina laxa, y nucléolo evidente observándoses algumas mitosis. El estudo inmunohistoquímico reveló positividad en las células tumorales con vimentina, CD 68 y los marcadores de células foliculares dendríticas CD 21, CD 35 y R 4/23. Se realizó microscopia electrónica confirmándose la presencia de prolongaciones citoplasmáticas con abundantes desmosomas. El paciente fue tratado con radioterapia local y 18 meses luego de la operación se halla sin evidencias de enfermedad. Creemos que con el mejor conocimiento de la entidad, la misma será más fácilmente y, tal vez, más frecuentemente diagnosticada. (AU)

A fast method for processing biologic material for electron microscopic diagnosis in infectious disease.

A fast method for processing biologic material for electron microscopy for precise and specific diagnosis of infectious agents is an increasing necessity. After different, reportedly fast methods were tested, a useful and quick technique was developed that provides well-preserved cellular structures, enabling the etiologic diagnosis of infectious agents even in necrotic tissue or other biologic material such as sputum, bronchoalveolar lavage, and the like. This procedure takes less than 3 hours.

Mast cell types in the lymph nodes of the opossum Didelphis albiventris (Marsupialia, Didelphidae).

Using histological and histochemical techniques, we have found a unique population of mast cells in the lymphatic sinuses of lymph nodes from different anatomical regions of the opossum. The lymphatic-sinus mast cells of the medullary sinuses were numerous, and could be easily distinguished from the connective-tissue mast cells of the dermis and lymph node capsule by their larger size and their enlarged cytoplasmic granules that were also more heterogeneous in shape and staining properties.

Reaçäo granulomatos associada a metástase de carcinoma epidermóide: importância da utilizaçäo de múltiplos métodos em patologia diagnóstica / Granulomatous reaction associated with metastatic epidermoid carcinoma: the importante of the use of multiple methods in diagnostic pathology

Os autores descrevem um caso de carcinoma epidermóde metastático em linfonodo cervical. Devido a presença de intensa reaçäo granulomatosa associada e a similaridade das células neoplásticas com as células epitelóides houve dificuldade diagnósticoa com base somente na análise histológica e citológica (biopsia aspirativa por agulha fina). Estudo por imunoperoxidase e microscopia eletrônica definiram o diagnóstico. É discutida a importância da utilizaçäo de múltiplos métodos em patologia cirúrgica e a patogênese da reaçäo granulomatosa associada as neoplasias malignas