Immunohistochemical study of the expression of fatty acid synthase and Ki-67 in salivary gland tumors

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

CD34 EXPRESSION IN STROMAL TUMORS OF THE GASTROINTESTINAL-TRACT

Gastrointestinal stromal tumors (GISTs) are mesenchymal tumors that may exhibit varied morphologic appearances (spindle, epithelioid) and biologic potentials. Given the continuing controversy regarding the type of cell differentiation present in these tumors (muscle versus nerve sheath versus null), we evaluated a set of GISTs, most of which had been previously examined for the presence of smooth muscle differentiation, for expression of CD34, a 115 kDa cell-surface progenitor cell marker also recently identified in a subset of mesenchymal tumors. Using antibody My 10 in deparaffinized, formalin-fixed tissue after pretreatment with microwave energy, we found that 46 of 57, or 81%, of GISTs were CD34+; this fraction of CD34+ tumors exceeded the fraction of these same GISTs found to show muscle actin (72%) expression. In addition, a consistently higher fraction of the tumor cell population was CD34+ than was muscle actin positive. These findings suggest that CD34 is a very sensitive marker for the identification of GISTs. CD34 is normally expressed by endothelial as well as perivascular cells, perhaps related to, but distinct from, vascular smooth muscle cells. While the nature of these latter cells is uncertain, the expression of CD34 in such a large fraction of GISTs may provide evidence of a unique differentiation pathway in these tumors.

Adenocarcinoma de cólon com diferenciação neuro-endócrina e escamosa. Relato de caso.

A tubular adenocarcinoma of the colon with solid area composed by small cells that was found by immunohistochemistry study using antibody to neuron-specific enolase (NSE) to possess neuroendocrine differentiation is related. In another areas of the tumor were visualized keratinizing squamous cells. The presence of neuro-endocrine and squamous cells features provide further evidence that neoplastic colonic cells have the capacity for multi-directional differentiation. The implications of this combination in relation to theories of tumor origin and differentiation and the prognostic significance of neuro-endocrine cells in malignant neoplasms of the gastrointestinal tract are discussed.

Considerações sobre o câncer localmente avançado de mama (CLAM) acrescidas de identificação dos receptores de estrogênios usando anticorpos monoclonais.

The effects of therapy in locally advanced breast cancer submitted to combined conventional telecobalt therapy plus chemotherapy with cyclophosphamide and 5-fluorouracil were studied in 49 patients. Associated to radical mastectomy in operable cases. Local tumor control was achieved in 86.7%. There were no local recurrences in those submitted to surgery but they reached 21.7% in inoperable patients who received only radiation therapy and chemotherapy. The median follow-up time for dead patients was 29.5 months and for living patients 79.3 months. The index of complete responses was 24.5% and the median disease free interval was 22.9 months. The overall survival rate, between three and five years, was 32.7%. Estrogen receptors were identified by using immunohistochemical assay ER-ICA and monoclonal antibody H222-SP gamma, Abbott. There were no differences in the complete response index, disease free interval and survival rates, among ER-positive and ER-negative patients, explained by the far advanced stage of the disease. ER-positivity was significantly correlated with histological features of the tumors: cell differentiation, presence of elastosis, absence of lymphocytic infiltration and absence of tumor necrosis.

Patterns of nucleolar activity during spermatogenesis of two triatomines, Panstrongylus megistus and P. herreri

The present work analyzed spermatogenesis in two species of triatomines (genus Panstrongylus) using silver-ion impregnation. The sex chromosomes of P. megistus and P. herreri had nucleolar organizing activity and became strongly impregnated during the phases of meiotic prophase I. Fragmentation of the nucleolus occurred in both species during the meiotic cycle. The nucleolar region could be observed up to diakinesis in meiotic prophase after which only nucleolar bodies and fragments were seen. Postmeiotic reactivation of rRNA synthesis occurred in these two species and was probably related to cell differentiation.

Collagen fiber reorganization in the rat ventral prostate following androgen deprivation: A possible role for smooth muscle cells

BACKGROUND. Stroma plays an essential role in glandular function in different systems. In the prostate, it is responsible for the development and maintenance of the differentiated state of the epithelium. The marked reduction in the epithelial compartment of the prostate gland following castration is followed by a similarly important reorganization of the stroma. In this work, we characterized the reorganization of collagen fibers in the ventral prostate of castrated rats. METHODS. Histochemical tests and immunohistochemistry for type I and III collagens plus confocal microscopy of triple-labeled (collagen III, actin, and DNA) tissue sections were employed. RESULTS. We showed that collagen fibers are composed of type I and type III collagens and that they are progressively concentrated around the epithelial structures (ducts and acini) and become increasingly undulated and folded. Double-labeling of collagen fibers and F-actin demonstrated that smooth muscle cells (SMC) are intimately associated with collagen fibers. CONCLUSIONS. The results demonstrated a marked reorganization of the collagen fibers, and suggest an active role of the SMC in the reorganization of the fibrillar components of the stroma. (C) 2000 Wiley-Liss, Inc.

Distribution of acid phosphatases in the hypopharyngeal glands from workers, queens and males of a Brazilian stingless bee Scaptotrigona postica Latreille: An ultrastructural cytochemical study

The present study reports the localization of acid phosphatase in the hypopharyngeal gland cells from workers (newly-emerged, nurse and forager), queens (newly-emerged and laying) and males (newly-emerged and mature for mating) of the Brazilian stingless bee, Scaptotrigona postica. The phosphatase activity varied in intensity and localization depending on the individual class, physiological age and the substrate used. In newly-emerged workers, the phosphatase-positive sites suggest the involvement of the enzyme with cellular differentiation that occurs in the presecretory phase, in nurse workers with protein synthesis and in forager workers with changes in cellular activity or glandular regression. In males mature for mating and laying queens, the positive sites are related to secretory activity, showing that the gland maintains some activity in spite of the regressive aspect. Of the substrates used, β-glycerophosphate gave the least specific localization.

The ultrastructure of the pre-meiotic and meiotic stages of spermatogenesis in Plagioscion squamosissimus (Teleostei, Perciformes, Sciaenidae)

Spermatogenesis of 'corvina' P. squamosissimus starts from a stem cell that gives rise to germ cells. These cells are enveloped by Sertoli cells, forming cysts. The germ cells in the cysts are all at the same stage of development and are interconnected by cytoplasmic bridges. Spermatogonia are the largest germ cells. In the cysts, these cells differentiate into primary spermatogonia and secondary spermatogonia. The primary spermatogonia are isolated in the cyst and give rise to the secondary spermatogonia. After several mitotic divisions, they produce spermatocytes I, which can be identified by synaptonemal complexes in the nucleus. The spermatocytes I enter the first phase of meiosis to produce the spermatocytes II. These are not very frequently seen because they rapidly undergo a second phase of meiosis to produce spermatids.

Localization of peroxidase activity in blood mononuclear phagocytes in pacu fish (Piaractus mesopotamicus)

The localization of peroxidase activity in different cell regions is used as a criterion for classifying the stage of maturity of mammalian mononuclear phagocytes, with a positive peroxidase reaction indicating the presence of monoblasts, promonocytes, monocytes, and macrophages. Peroxidase activity was observed ultrastructurally in the circulating blood of pacu fish (Piaractus mesopotamicus), identifying monoblasts, promonocytes, monocytes, and macrophages. These observations suggest that differentiation of mononuclear phagocytes occurs in the blood circulation of fish, whereas in mammals, monoblasts and promonocytes are detected in bone marrow, with only monocytes detected in circulating blood and differentiation into macrophages occurring in other body compartments.

Cytokeratins in epithelia of odontogenic neoplasms

Neoplasms and tumours related to the odontogenic apparatus may be composed only of epithelial tissue or epithelial tissue associated with odontogenic ectomesenchyme. The immunohistochemical detection of different cytokeratins (CKs) polypeptides and vimentin has made it easier to explain the histogenesis of many epithelial diseases. The present study aimed to describe the immunohistochemical expression of cytokeratins 7, 8, 10, 13, 14, 18, 19 and vimentin in the epithelial components of the dental germ and of five types of odontogenic tumours. The results were compared and histogenesis discussed. All cells of the dental germ were positive for CK14, except for the preameloblasts and secreting ameloblasts, in which CK14 was gradually replaced by CK19. CK7 was especially expressed in the cells of the Hertwig root sheath and the stellate reticulum. The dental lamina was the only structure to express CK13. The reduced epithelium of the enamel organ contained CK14 and occasionally CK13. Cells similar to the stellate reticulum, present in the ameloblastoma and in the ameloblastic fibroma, were positive for CK13, which indicates a nature other than that of the stellate reticulum of the normal dental germ. The expression of CK14 and the ultrastructural aspects of the adenomatoid odontogenic tumour probably indicated its origin in the reduced dental epithelium. Calcifying odontogenic epithelial tumour is thought to be composed of primordial cells due to the expression of vimentin. Odontomas exhibited an immunohistochemical profile similar to that of the dental germ. In conclusion, the typical IF of odontogenic epithelium was CK14, while CK8, 10 and 18 were absent. Cytokeratins 13 and 19 labelled squamous differentiation or epithelial cells near the surface epithelium, and CK7 had variable expression.

Collagen fibers in human prostatic lesions: histochemistry and anisotropies

The present study focuses on establishing patterns of collagen fibers distribution in prostatic nodular hyperplasia and adenocarcinomas, in comparison with the normal tissue. Sections of prostatic transurethral resection were subjected to Gömöri's method for collagen fibers and reticulin and analyzed under ordinary and polarized light microscopy. Controls and hyperplastic regions present collagen fibers with variable thickness that run in different directions, establishing a tridimensional network. These fibers exhibit birefringence and dichroism thus demonstrating their fibrillar integrity. On the other hand, increased variability in collagen fiber distribution and anisotropical properties occur in adenocarcinomas evaluated in accordance with the Gleason's score. In some of their areas, a well-defined collagen network delimitates the base of transformed epithelial cells whereas in other areas the collagen fibers are disorganized and do not establish a boundary between the epithelial structures and the stroma. In these areas, collagen is found in the stroma. It was also observed that adenocarcinoma tumor cells rest on a scaffold of thin and dendritic collagen fibers. Collagen fibers of the prostatic stroma of the adenocarcinomas may show a modification in arrangement and fibrillar compactness. In prostatic nodular hyperplasia, there is no change in collagen molecular integrity, since collagen affinity for silver and collagen birefringence are similar to controls. In adenocarcinoma with high dedifferentiation degree, thin and branched strongly argyrophilic and birefringent collagen fibers are detected in regions of cell proliferation. In the adjacent stroma, hyaline plaques are indicative of matrix degradation or remodellation.

Morphological aspects of muscle regeneration in the Nile tilapia (Oreochromis niloticus)

The aim of our study was to analyze the morphological events in the skeletal muscle of the Nile tilapia (Oreochromis niloticus) after a traumatic lesion. Thirty-two fish were used, on which a small longitudinal incision was made in the muscle. The fish were sacrificed after 7, 14, 21, and 42 days and muscle samples were collected from the lesion and processed for morphological analysis. Muscle regeneration in the tilapia occurred gradually through the analyzed period, possibly due to the proliferation and differentiation of myosatellite cells, which were more morphologically evident 7 and 14 days after lesion.

Rhabdomyomatous carcinoma of the thymus

Myoid cells have been described in the thymus in association with a variety of benign and malignant conditions. The presence of a benign rhabdomyomatous component in a malignant primary thymic epithelial neoplasm, however, is extremely rare. A case of poorly differentiated carcinoma of the thymus arising in the posterior mediastinum containing a prominent rhabdomyomatous component is described. The patient, a 70-year-old woman, was seen for a large posterior mediastinal mass. An open chest biopsy revealed an extensively necrotic tumor composed of islands of atypical cells with vesicular nuclei and prominent nucleoli with numerous mitotic figures admixed with abortive glandular structures. Interspersed with the malignant epithelial components were islands of large cells containing brightly eosinophilic cytoplasm and small, round, excentrically placed nuclei. Immunohistochemical studies showed strong positivity of the epithelial cells for cytokeratin and strong positivity of the myoid cells for pan-actin, desmin, and myogenin. The possible relationship of the rhabdomyomatous component of this tumor with the myoid cells of the thymus is discussed.

Growth and developmental outcomes of the extremely preterm infant

Objetive: To provide information for pediatricians and neonatologists to create realistic outcome expectations and thus help plan their actions. Sources of data: Searches were made of the Cochrane Library, MEDLINE, and Lilacs databases. Summary of the findings: The assessment of growth and development over the first 2-3 years must adjust chronological age with respect of the degree of prematurity. There is special concern regarding the prognoses of small for gestational age preterm infants, and for those with bronchopulmonary dysplasia. Attention must be directed towards improving the nutrition of extremely low birth weight infants during their first years of life; these infants have high prevalence levels of failure to catch-up on growth, diseases and rehospitalizations during their first 2 years. They are frequently underweight and shorter than expected during early childhood, but delayed catch-up growth may occur between 8 and 14 years. Extremely low birth weight infants are at increased risk of neurological abnormalities and developmental delays during their first years of life. Educational, psychological, and behavioral problems are frequent during school years. Teenage and adult outcomes show that although some performance differences persist, social integration is not impaired. Conclusions: The growth and neurodevelopment of all ELBW infants must be carefully monitored after discharge, to ensure that children and their families receive adequate support and intervention to optimize prognoses. Copyright © 2005 by Sociedade Brasileira de Pediatria.

Diferenciação hepatocítica de células-tronco mesenquimais da medula óssea humana

Some recent articles have reported that mesenchymal stem cells (MSCs) can be induced to express hepatocyte markers by transplanting them into animal models of liver damage, or by in vitro culture with growth factors and cytokines. In this study, the aim is to evaluate the behavior of MSCs subjected to induction of hepatocyte differentiation. The MSCs were isolated from the bone marrow of 4 normal donors, characterized and subjected to both in vitro and in vivo induction of hepatocyte differentiation. The in vitro induced cells showed morphological changes, acquiring hepatocyte-like features. However, the immunophenotype of these cells was not modified. The induced cells exhibited no increase in albumin, cytokeratin 18 or cytokeratin 19 transcripts, when analyzed by real-time RT-PCR. The expression of albumin, cytokeratin 18 and alpha fetoprotein was also unchanged, according to immunofluorescence tests. In vivo, the MSC demonstrated a potential to migrate to damaged liver tissue in immunodeficient mice. Taken together, the results suggest that bone marrow MSCs are incapable of in vitro differentiation into hepatocytes by the approach used here, but are capable of homing to damaged hepatic tissue in vivo, suggesting a role for them in the repair of the liver. This contribution to tissue repair could be associated with a paracrine effect exerted by these cells.