Raimunda Telma de Macedo Santos

Human fatal yellow fever. Immunohistochemical detection of viral antigens in the liver, kidney and heart.

An immunohistochemical method to detect yellow fever antigen was developed using immune sera from rabbits and hamsters and hyperimmune ascitic fluid from mice. A search for the antigen was carried out in liver, kidney and heart in three fatal cases of yellow fever. In the liver it was present in the cytoplasm of hepatocytes, Councilman bodies and Kupffer cells. Yellow fever antigen was also detected in renal tubular epithelium and in groups of myocardial fibers. These findings suggest that viral replication occurs at sites other than the liver. Since yellow fever shares many features with other haemorrhagic fevers the use of immunohistochemistry can impart a significant improvement in the accuracy of its histopathological diagnosis.

Trypanosoma cruzi strains and autonomic nervous system pathology in experimental chagas disease

Lesions involving the sympathetic (para-vertebral ganglia) and para-sympathetic ganglia of intestines (Auerbach plexus) and heart (right atrial ganglia) were comparatively analyzed in mice infected with either of three different strain types of Trypanosoma cruzi, during acute and chronic infection, in an attempt to understand the influence of parasite strain in causing autonomic nervous system pathology. Ganglionar involvement with neuronal destruction appeared related to inflammation, which most of the times extended from neighboring adipose and cardiac, smooth and striated muscular tissues. Intraganglionic parasitism was exceptional. Inflammation involving peripheral nervous tissue exhibited a focal character and its variability in the several groups examined appeared unpredictable. Although lesions were generally more severe with the Y strain, comparative qualitative study did not allow the conclusion, under the present experimental conditions, that one strain was more pathogenic to the autonomic nervous system than others. No special tropism of the parasites from any strain toward autonomic ganglia was disclosed.

Can living in the surroundings of a petrochemical complex be a risk factor for autoimmune thyroid disease

BACKGROUND Based on a suspicion raised by a health professional and due to a subsequent legal request, a cross-sectional study was made with a comparison group to investigate a possible excess of Hashimotos thyroiditis-HT and antibodies-ATA in the surroundings of a Petrochemical Complex. METHODS People of both sexes aged over 20 years were investigated in a random sample of residents in the area surrounding the Petrochemical Complex. Controls were investigated in an area with steel industries. In the areas searched, participants were chosen randomly and stratified a priori by sex and age group. As a result, 90.5% of the expected sample was obtained, totaling 1533 individuals. HT and ATA prevalences were compared by the chi-square test. Logistic regression was used to control the possible confounding factors for HT and ATA. RESULTS Both TH (9.3%) and ATA (17.6%) prevalences were higher in the Petrochemical Complex area than in the control area (3.9% and 10.3%, respectively). After controlling the possible confounding factors, the POR for living in the surroundings of the Complex and presenting HT was 2.39 (CI95%: 1.42-4.03). According to the ATA criterion, the POR for living in the surroundings of the Complex was 1.78 (CI95%: 1.23-2.60). CONCLUSIONS The authors have found higher prevalence and risk of developing thyroiditis and anti-thyroid antibodies among residents of areas surrounding the Petrochemical Complex and think these findings need to be further studied in similar areas.

Immunohistochemical Detection of Toxocaral Antigens in Human Liver Biopsies

The distribution of Toxocara species larval antigens in tissue was studied by immunohis tochemical techniques in five human cases of toxocariasis. Patients had a clinical his tory suggestive of the infection, a positive enzyme-linked immunosorbent assay test for toxocaral antibodies, and histopathologic patterns of toxocariasis. Liver biopsies were taken from all five patients, usually under suspicion of liver abscess or of meta static or primary liver neoplasia. In one case a segment of the right colon adjacent to the liver lesions was also examined. Immunohistochemical techniques using polyclonal antiserum raised in rabbits against excretory secretory (TES) antigens of Toxocara canis larvae detected antigen deposits phagocyte ed by macrophages at the periphery of eosinophil-rich granulomas, in the portal inflammatory infiltrate, between epithelioid cells close to the areas of necrosis, and sequestered in the collagen of the periportal region. Both nonabsorbed and Strongyloides venezuelensis and Ascaris suum absorbed sera essentially detected similar antigenic sites, but these sites were more frequently observed and more evident when the former was used. The importance of antigen detection for the etiologic diagnosis of eosinophilic granulomatous inflammation and eosinophil-rich inflammatory infiltrates is stressed. Int J Surg Pathol 2(2):117-124, 1994

An immunohistochemic assay to localize leptospires in tissue specimens

Os autores apresentam uma tecnica de imunoperoxidase para a identificacao de leptospiras em cortes de rim fixados em formol e emblocados em parafina. A variante metodologica inclui a utilizacao do complexo peroxidase-antiperoxidase, conferindo alta sensibilidade a reacao. Sao, ainda, discutidas algumas possiveis aplicacoes do metodo ao estudo do acometimento renal na leptospirose.

Controle de qualidade interlaboratorial em imuno-histoquímica: citoceratinas e receptor de estrógeno como modelos

INTRODUCAO: O grande incremento do uso da imuno-histoquimica (IHQ) em numerosos laboratorios de anatomia patologica amplia o poder de resolucao diagnostica, mas traz certo grau de heterogeneidade de procedimentos e resultados. Seguindo recentes propostas da literatura internacional, participantes do Clube de IHQ da Sociedade Brasileira de Patologia desenvolvem acoes de controle de qualidade, aplicando protocolos de sua rotina a pesquisa de antigenos que sirvam como indicadores de qualidade da reacao. MATERIAL E METODO: Um total de dez laboratorios participou das duas etapas deste estudo, cujos marcadores foram pancitoceratinas e receptores de estrogeno. Com lâminas controle recebidas dos laboratorios, cada participante efetuou a tecnica de IHQ conforme sua pratica diaria, retornando as lâminas juntamente com o formulario de procedimento. A avaliacao semiquantificada de 0 a 4 da intensidade da reacao especifica e de 0 a 3 da coloracao de fundo e da qualidade da tecnica histologica foram atribuidas individual e sigilosamente durante a projecao em data show em reuniao do Clube de IHQ, gerando um escore final. RESULTADOS E DISCUSSAO: As variacoes na imunocoloracao de citoceratinas e receptor de estrogeno nao comprometeram sua deteccao nas lâminas preparadas nos diversos laboratorios. Tais variacoes associaram-se a diversidade de sistemas de recuperacao antigenica e de amplificacao, resultando ora em imunopositividade menos intensa, ora em maior fundo. Outros estudos devem abordar questoes de interpretacao, incluindo-se criterios para semiquantificacao.

Detecção imunoistoquímica das oncoproteínas p21ras, c-myc E p53 no carcinoma hepatocelular e no tecido hepático não-neoplásico

BACKGROUND Genetic and epigenetic alterations have been described in animal hepatocarcinogenesis models but need to be studied in human being. AIMS To assess the immunoreactivity of p21ras, c-myc and p53 oncoproteins in hepatocellular carcinoma and non neoplastic tissue. Association of the immunoreactivity of these markers with histological grades and patterns, hepatitis B and C were additionally studied. METHODS Detection of oncoproteins p21ras, c-myc and p53 was performed immunohistochemically in hepatocellular carcinoma (47 cases) and surrounding non neoplastic liver tissue (40 cases). RESULTS Oncoproteins p21ras, c-myc and p53 were detected in 44,7%, 53,2% and 36,2% of the hepatocellular carcinoma cases, respectively. The p21ras and c-myc immunoreactivity has shown a significant association. However there was no association of p21ras, c-myc and p53 detection with hepatitis B and C virus infections, histological grades and patterns. The same significant association between p21ras and c-myc was observed in non-neoplastic tissue with cirrhosis when compared with tissue without it. The p53 immunoreactivity was negative in all non-neoplastic liver tissue samples. CONCLUSIONS The immunoreactivity detection of p21ras, c-myc and p53 corroborates previous evidence of their detection in hepatocellular carcinoma that suggest the participation of these proteins in human hepatocarcinogenesis. The significant association between p21ras and c-myc oncoproteins in hepatocellular carcinoma and in cirrhosis can point to an interaction between them mainly, in hepatocarcinogenesis that occurs through cirrhosis.

Análise de indicadores internos e externos relevantes à resolutividade diagnóstica em laboratório de referência em imuno-histoquímica

OBJECTIVES: The aim of this study was to evaluate the resolutivity of immunohistochemical (IHC) assays on neoplastic samples in a public health laboratory and to assess the influence of communication between the requiring institution and reference one on the quality of the IHC diagnosis. MATERIAL AND METHODS: One thousand oncological samples from eight public hospitals were submitted to IHC assay: 500 immediately before and 500 after an intervention demanding further information from the requiring pathologist. Antigen retrieval was performed in a pressure cooker and the detection system was LSAB plus System. The results were expressed as positive, negative or inconclusive. Information about paraffin blocks, fixatives, official requiring form, the attachment of original anatomopathological report, topography of the lesion, age and gender of the patients was collected. RESULTS AND CONCLUSION: From 989 samples, 5,719 slides were stained by IHC, leading to a resolutivity for 919/989 (92.9%). The number of antigen tested ranged from one to 22 - average of 5.8 for case. Panels with up to five antigens per case resolved 534 samples, whereas up to 10 markers were necessary to resolve 919 samples. Even nowadays, basic information, such as anatomopathological reports, age, gender, representative and technically superior paraffin block are not always available to the reference laboratory. The improvement of such communication is essential to rationalize the flux of immunohistochemical tests and to enhance the quality of diagnostic conclusions.