Polyclonal endemicity of Pseudomonas aeruginosa in a teaching hospital from Brazil: molecular typing of decade-old strains

Pseudomonas aeruginosa infections cause significant mortality and morbidity in health care settings. Strategies to prevent and control the emergence and spread of P. aeruginosa within hospitals involve implementation of barrier methods and antimicrobial stewardship programs. However, there is still much debate over which of these measures holds the utmost importance. Molecular strain typing may help elucidate this issue. In our study, 71 nosocomial isolates from 41 patients and 23 community-acquired isolates from 21 patients were genotyped. Enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) was performed. Band patterns were compared using similarity coefficients of Dice, Jaccard and simple matching. Strain similarity for nosocomial strains varied from 0.14 to 1.00 (Dice); 0.08 to 1.00 (Jaccard) and 0.58 to 1.00 (simple matching). Forty patterns were identified. In most units, several clones coexisted. However, there was evidence of clonal dissemination in the high risk nursery, neurology and two surgical units. Each and every community-acquired strain produced a unique distinct pattern. Results suggest that cross transmission of P. aeruginosa was an uncommon event in our hospital. This points out to a minor role for barrier methods in the control of P. aeruginosa spread.

Kaposi's sarcoma-associated herpesvirus infection and Kaposi's sarcoma in Brazil

Kaposi's sarcoma (KS) became a critical health issue with the emergence of acquired immunodeficiency syndrome (AIDS) in the 1980s. Four clinical-epidemiological forms of KS have been described: classical KS, endemic KS, iatrogenic KS, and AIDS-associated KS. In 1994, Kaposi's sarcoma-associated herpesvirus (KSHV) or human herpesvirus type 8 was identified by Chang and colleagues, and has been detected worldwide at frequencies ranging from 80 to 100 percent. The aim of the present study was to evaluate the frequency of KSHV infection in KS lesions from HIV-positive and HIV-negative patients in Brazil, as well as to review the current knowledge about KS transmission and detection. For these purposes, DNA from 51 cases of KS was assessed by PCR: 20 (39.2 percent) cases of classical KS, 29 (56.9 percent) of AIDS-associated KS and 2 (3.9 percent) of iatrogenic KS. Most patients were males (7.5:1, M/F), and mean age was 47.9 years (SD = ± 18.7 years). As expected, HIV-positive KS patients were younger than patients with classical KS. On the other hand, patients with AIDS-associated KS have early lesions (patch and plaque) compared to classical KS patients (predominantly nodular lesions). This is assumed to be the result of the early diagnose of KS in the HIV-positive setting. KSHV infection was detected by PCR in almost all cases (48/51; 94.1 percent), irrespectively of the clinical-epidemiological form of KS. These results show that KSHV is associated with all forms of KS in Brazilian patients, a fact that supports the role of this virus in KS pathogenesis.

Epstein-Barr virus infection and gastric carcinoma in São Paulo State, Brazil

Epstein-Barr virus (EBV) is a ubiquitous herpesvirus, and most people have serological evidence of previous viral infection at adult age. EBV is associated with infectious mononucleosis and human cancers, including some lymphomas and gastric carcinomas. Although EBV was first reported in lymphoepithelioma-like gastric carcinoma, the virus was also found in conventional adenocarcinomas. In the present study, 53 gastric carcinomas diagnosed in São Paulo State, Brazil, were evaluated for EBV infection by non-isotopic in situ hybridization with a biotinylated probe (Biotin-AGACACCGTCCTCACCACCC GGGACTTGTA) directed to the viral transcript EBER-I, which is actively expressed in EBV latently infected cells. EBV infection was found in 6 of 53 (11.32 percent) gastric carcinomas, mostly from male patients (66.7 percent), with a mean age of 59 years old. Most EBV-positive tumors were in gastric antrum. Two EBV-positive tumors (33.3 percent) were conventional adenocarcinomas, whereas four (66.7 percent) were classified as lymphoepithelioma-like carcinomas. EBV infection in gastric carcinomas was reported elsewhere in frequencies that range from 5.6 percent (Korea) up to 18 percent (Germany). In Brazil, a previous work found EBV infection in 4 of 80 (5 percent) gastric carcinomas, whereas another study found 4.7 and 11.2 percent of EBV-positive gastric carcinomas of Brazilians of Japanese origin or not, respectively. In the present study, the frequency of EBV-positive gastric carcinomas is similar to that reported in other series, and the clinicopathologic characteristics of these EBV-positive tumors are in agreement with the data in the literature.

Effect of pancreas transplantation on the prevention of nephropathy in alloxan-induced diabetic rats

We studied the effects of pancreas transplantation on kidney lesions of rats with alloxan-induced diabetes. Ninety inbred male Lewis rats were randomly assigned to 3 experimental groups: group NC included 30 non-diabetic control rats, group DC included 30 alloxan-induced diabetic control rats, and group PT include 30 alloxan-induced diabetic rats that received pancreas transplants from normal donor Lewis rats. Each group was further divided into 3 subgroups of 10 rats which were sacrificed at 1,3, and 6 months of follow-up, respectively. Clinical and laboratory parameters during these periods were documented. The kidneys of 5 rats in each subgroup were studied and 50 glomeruli and tubules from each kidney were analyzed by light microscopy by two different investigators in a double-blind study. There was progressive glomerular basement membrane thickening (GBMT), mesangial enlargement (ME), and Bowman's capsule thickening (BCT) in kidneys of rats in the 3 experimental groups during follow-up. These alterations were significantly higher in DC rats (GBMT: 1.99 ñ 0.31; ME: 2.00 ñ 0.33; BCT: 1.88 ñ 0.27) when compared to NC (GBMT: 1.54 ñ 0.30; ME: 1.56 ñ 0.47; BCT: 1.36 ñ 0.35) and PT rats (GBMT: 1.49 ñ 0.29; ME: 1.57 ñ 0.36; BCT: 1.35 ñ 0.28) at 6 months (P<0,01). The extent of GBMT, ME, and BCT observed in DC rats at 1 and 3 months was not significantly different from NC and PT rats. The amount of kidney lesions in PT rats was similar to that of NC rats and lower than those of DC rats at 6 months (P<0.01). In addition, Armanni-Ebstein lesions of the tubules (AE) and tubular lumen protein (PRO) observed in DC rats were not present in NC or PT rats. We conclude that pancreas transplantation in alloxan-induced diabetic rats prevents the development of kidney lesions beginning at 6 months after transplantation.

Detection of infectious disease agents in tissue by immunocytochemistry

1. Immunocytochemical procedures have played an increasingly larger role in the identification of infectious disease agents in tissue sections owing to the increased availability and specificity of antibody reagents, the great sensitivity of the methods, and the relative facility with which the studies are performed. 2. Immunocytochemical methods can be applied to routine formalin-fixed tissue for the detection of infectious agents such as viruses, bacteria, fungi, and protozoa among other microorganisms for diagnostic and research purposes

Detection of cell proliferation in tissue sections

1. Cell proliferation is of interest since abnormal cell proliferation appears to be a precursor of tumorigenesis and also because the quantitative description of cell proliferation in tumors can be used to predict the biological behavior of a particular neoplasia. 2. There are several reliable methods of studying cell proliferation in tissues. One of the most important is the detection of the Ki67 defined antigen in frozen sections. The number of cells expressing Ki67 correlates with histological grades of tumors and can also be predictive of clinical outcome. The Ki67 can be localized in tissue sections using monoclonal antibodies in association with the immunoperoxidase technique. 3. Proliferating cell nuclear antigen (PCNA) is a component of DNA polymerase-delta and is another important cell proliferation marker manifesting a striking increase in concentration during the S phase of the cell cycle. 19A2 and PC10 are two different monoclonal antibodies which can be employed to detect PCNA in paraffin-embedded tissues. 4. Molecular biology has also been making a great contribution to the study of cell proliferation. The most recent innovation in tissue identification of proliferating cells is the use of in situ hybridization for the localization of histone H3 and/or H4 mRNA. H3 mRNA-positive cells appear to be present in basal cells of the skin and in crypt cells of the intestine which are sites with high proliferation rate

Utilidade dos metodos imuno-histoquimicos para o diagnostico anatomo-patologico / The usefulness of immunohistochemical methods for the anatomopathologic diagnosis

Com a finalidade de avaliar a contribuicao da imuno-histoquimica ao diagnostico morfologico estudamos 949 casos enviados em consulta ao Laboratorio de Imuno-histoquimica do Departamento de Patologia da Faculdade de Medicina de Botucatu no periodo de 1984 a 1989. Todos os casos foram submetidos as tecnicas de imunoperoxidase pelos metodos do PAP ou ABC. A imuno-histoquimica confirmou o diagnostioco preferencial em 468 casos (49,3 por cento); nao contribuiu em 114 casos (12 por cento) e propos um diagnostico insuspeitado em 49 casos(5,2 por cento). Nos casos em que nao contribuiu, a fixacao inadequada do tecido foi uma das principais responsaveis pela falha da tecnica. A analise destes dados demonstra qua a imuno-histoquimica contribuiu significativamente no diagnostico anatomo-patologico e que deve ser executada por patologista cirurgico treinado e experiente.

Expressäo antigênica em carcinomas do plexo coróide humano: relato de dois casos / Antigenic expression in human choroid plexus carcinoma: report of 2 cases

Neoplasias provenientes do epitélio de revestimento do plexo coróide säo incomuns, tendo sido descritos 6 padröes morfológicos. O padräo anaplásico, também denominado carcinoma do plexo coróide, é o de menor freqüência e pode dar metástase fora do SNC. A distinçäo histológica desses tumores, particularmente da variedade anaplásica, com outras neoplasias primárias e metastáticas no SNC pode ser fidifícil. O uso de técnicas imunocitoquímicas em parafina tem-se mostrado útil no esclarecimento das linhagens tumorais. Os papilomas do plexo coróide têm, no entanto, sido objeto de controvérsia, por sua complexa expressäo antigênica. Usando a técnica de imunoperoxidase (sistema avidina-biotina-peroxidase) pesquisaram-se, em dois casos da variedade anaplásica, os seguintes marcadores: proteína glial fibrilar ácida (GFAP) com anticorpo monoclonal e policlonal; ceratinas de 40-50kDa, ceratinas de 60-70kDa (callus ceratina), enolase neuronal específica (NSE) e proteína S-100, com anticorpos monoclonais. Os dois tumores mostraram positividade para NSE, proteína S-100 e ceratina de 40-50kDa: uma das duas neoplasias mostrou diferenciaçäo glial, revelando positividade para GFAP tanto como anticorpo monoclona quanto policlonal

Immunohistochemical identification of lysozyme and vimentin in an experimental malignant fibrous histiocytoma

The inmmunoperoxidase avidin-biotin-peroxidase complex method was used to investigate the presence of histiocyte markers such as lysozyme, alpha-1-antitrypsin (A1AT) and alpha-1-anti-chymotrypsin (A1ACT) and of vimetin, a specific marker for mesenchcymal differentiation, in a sspontaneous and transplantable rat tumor of supposed fibroblastic-histiocytic origin. Positive staining was obtained for lysozyme and vimetin but A1AT and A1ACT were not demonstrable in any of the tumor sections. These results provide evidence for the fibro-histiocytic nature of the tumor studied and suggest its classification as a malignant fibrous histiocytoma (MFH)