Evaluation of double immunocytochemical staining for CK20 and P53 as a potential adjunct to cytology for urothelial cancer diagnosis.

OBJECTIVE: To evaluate double immunocytochemical staining with p53 and CK20, as a tool for improving the accuracy of urinary cytology. The aim of the present study was to clarify the diagnostic significance of the expression of these markers and to investigate the possibility of using this information for better monitoring of bladder cancer patients during follow-up. MATERIAL AND METHODS: One hundred and twenty-five urine cytology cases were retrieved with corresponding histology from our files. One ThinPrep® smear was available for each of them and dual immunocytological staining for p53 and CK20 was performed. Eleven cases were excluded from the study because of hypocellularity. The material comprised 58 malignant, 36 atypical and 20 negative for malignancy cases. Immunocytochemistry was evaluated by two cytopathologists, blinded to the histological diagnosis or follow-up data. A cut-off threshold of five stained atypical cells, according to the literature, was used for evaluation. RESULTS: Fifty-two out of 58 malignant cases were positive for at least one of the markers (89.6%). In the atypical and negative groups, 18 (50%) and 5 (25%) cases were positive, respectively. Accuracy parameters evaluation for cytology versus the combination of cytology with immunocytological staining were: sensitivity 73.4% versus 91.1%, specificity 100% versus 74.3%, positive predictive value (PPV) 100% versus 88.9% and negative predictive value (NPV) 62.5% versus 78.8%. CONCLUSIONS: Double immunocytochemical staining for p53 and CK20 is easy to perform and evaluate and can improve cytology sensitivity. It is helpful in establishing a diagnosis of malignancy and may be used as a triage tool to select patients that require cystoscopy during clinical follow-up.

Audit of cytology of upper urinary tract.

OBJECTIVE: Cytology is an essential tool for the investigation of urinary tract malignancy. In this audit, we aimed to assess our laboratory performance in the diagnosis of upper urinary tract malignancy and to use the information provided to improve our service. METHODS: We retrieved cytology reports of upper urinary tract specimens from two periods, re-evaluated the cases, compared the reports with histology data and estimated the sensitivity, specificity and positive predictive value (PPV). In the time interval between the two periods, we adopted new terminology, established better communication with clinicians and gained experience in the field. Finally, the data from the two periods were compared. RESULTS: In phase A, we estimated a sensitivity of 73%, specificity of 86% and PPV of 84.6%. As a result of the cytological re-evaluation, correlation with histology and clinical follow-up, plus communication with the clinicians during the audit, we established new terminology and a new request form. A three tiered grading system of atypia (mild, moderate and severe) was replaced by a two tiered grading system. The first category "atypia probably benign" corresponded to "mild atypia" while the second category "atypia, not otherwise specified" corresponded to "moderate atypia". The cases diagnosed as "severe atypia" were reclassified as "suspicious for malignancy". In phase B, the sensitivity, specificity and PPV were 75%, 89% and 90%, respectively. CONCLUSIONS: Our laboratory performance is in concordance with reported data and has been improved through this study. The audit process is extremely valuable for the identification of problems, for taking action and, finally, for the improvement of the clinical cytology service in the field of upper urinary tract malignancy.

Diagnosis of the strongyloid nematode Strongyloides venezuelensis in experimentally infected rats.

Strongyloides venezuelensis is an intestinal nematode of rats, frequently used as a model for studying human and animal strongyloidiasis. In the present study, we evaluated parasitological, serological and molecular methods for the diagnosis of experimental S. venezuelensis in rats, Rattus norvegicus. Blood and faecal samples were collected and analysed up to 60 days post infection (pi) with adult worm recovery occurring from 5 to 45 days pi. Using an enzyme-linked immunosorbent assay (ELISA), serum levels of IgG antibodies increased up to 28 days pi, thereafter decreasing by day 60 pi. Polymerase chain reaction (PCR) assays detected S. venezuelensis DNA in faecal samples of rats from 5 to 21 days pi. The present study therefore represents the first step towards improving the diagnosis of experimental strongyloidiasis.

Conventional PCR for molecular diagnosis of human strongyloidiasis.

Strongyloidiasis is frequently asymptomatic and diagnosis of latent infection is difficult due to limitations of current parasitological and serological methods. This study aimed to verify the use of conventional polymerase chain reaction (PCR) assay for molecular diagnosis of Strongyloides stercoralis infection. Fresh stool samples were obtained from 103 individuals: 33 S. stercoralis positive, 30 positive for other parasites and 40 negative for parasitological methods. These samples were examined by the Lutz, Rugai and agar plate culture methods and conventional PCR assay. Two sets of primers (S. stercoralis species-specific and genus-specific sets), located in the 18S ribosomal RNA gene, were used for PCR. Of the 33 samples positive for S. stercoralis by parasitological methods, 28 (84.8%) were also detected by PCR assay using species-specific primers and 26 (78.8%) using genus-specific primers. Among the stool samples negative by parasitological methods, seven (17.5%) were positive by PCR using species-specific primers and two (5.0%) using genus-specific primers. In conclusion, the conventional PCR assay described in this study using a species-specific primer pair provided a molecular method for S. stercoralis diagnosis in human stool samples.

HCV viremia drives an increment of CD86 expression by myeloid dendritic cells.

The host immune response, including innate and adaptive immunity, plays a critical role in determining the outcome of viral infection. Nevertheless, little is known about the exact reasons for the failure of the host immune system in controlling hepatitis C virus (HCV) infection. Impairment of dendritic cells (DCs) function is probably one of the mechanisms responsible for immune evasion of HCV. In this study, the frequency and phenotype of DCs subsets were analyzed in three groups: HCV-infected individuals who developed viral persistence (1), HCV-infected individuals who spontaneously cleared the virus (2) and HCV-seronegative uninfected subjects (3). The results showed that the frequency of DCs subsets was not statistically significant between groups. Plasmacytoid DCs circulating exhibited an immature phenotype characterized by low expression of CD86. On the other hand, CD86 expression in myeloid DCs was significantly higher in chronic infected individuals compared to healthy controls (P=0.037). A positive correlation was observed between CD86(+) myeloid DC (mDC) and HCV viral load (r=0.4121, P=0.0263). These results suggest that HCV did not have an inhibitory effect on mDC maturation and the HCV viremia drives the increase of CD86 expression in mDC. The regulation of DCs maturation and migration lies at the level of intracellular signaling. HCV can activate or block intracellular signaling pathways and alter DC function. In conclusion, the present study suggests that imbalance of DC maturation by the virus represents a mechanism of evasion of the immune system despite the fact that HCV viremia appears to exert a "stimulatory" effect on cell-surface immune phenotype.

Cryopreservation does not alter karyotype, multipotency, or NANOG/SOX2 gene expression of amniotic fluid mesenchymal stem cells.

Cryopreservation of mesenchymal stem cells from amniotic fluid is of clinical importance, as these cells can be harvested during the prenatal period and stored for use in treatments. We examined the behavior of mesenchymal stem cells from human amniotic fluid in culture that had been subjected to cryopreservation. We assessed chromosomal stability through karyotype analysis, determined whether multipotent capacity (differentiation into adipogenic, chondrogenic, and osteogenic cells) is maintained, and analyzed SOX2 and NANOG expression after thawing. Five amniotic fluid samples were cryopreserved for 150 days. No chromosomal aberrations were observed. The expression levels of NANOG and SOX2 also were quite similar before and after cryopreservation. Capacity for differentiation into adipogenic, chondrogenic, and osteogenic tissues also remained the same. We conclude that cryopreservation of amniotic fluid does not alter karyotype, NANOG/SOX2 gene expression, or multipotent capacity of stem cells that have been collected from amniotic fluid during pregnancy.

A985G mutation incidence in the medium-chain acyl-CoA dehydrogenase (MCAD) gene in Brazil.

In view of the serious consequences of medium-chain acyl-CoA dehydrogenase (MCAD) deficiency and the absence of information about its incidence in the Brazilian population, we examined the frequency of the A985G mutation in the MCAD gene. A retrospective analysis was made of data on 1722 individuals (844 females) genotyped for the A985G mutation in the MCAD gene, using genomic DNA extracted from peripheral blood leukocytes and genotyping with PCR-RFLP; 0.41% of these individuals were heterozygous for the A985G mutation. The mutant homozygous genotype was not found. The 985G mutant and 985A normal alleles had allelic frequencies of 0.0020 and 0.9980, respectively. Given the A985G allele frequency, genotyping would be recommended in cases of family history of MCAD deficiency and sudden infant death syndrome, and when there is suspicion of medium-chain fatty acid metabolic alterations; genetic counseling should be offered in cases involving 985GG and A985G individuals and consanguineous marriages.

Utility of STR markers for the molecular diagnosis of a large Brazilian family with Charcot-Marie-Tooth disease.

Charcot-Marie-Tooth type 1A disease (CMT1A) is most frequently caused by a tandem DNA duplication of a 1.4-Mb genomic fragment in the 17p11.2-12 chromosomal region. The disease is probably the product of a dosage effect of the peripheral myelin protein 22 gene located within the duplicated segment. We sought to study the largest reported Brazilian family with suspected diagnosis of CMT1A using eight short tandem repeat microsatellite markers. In addition, we analyzed the informativeness of these markers in the normal Brazilian population. The duplication was found in 12 members of the family. In two patients with CMT1A symptoms, the duplication was not detected, and one asymptomatic subject showed the duplication. D17S2230, D17S9B, D17S2220, D17S2227, D17S9A, and D17S4A markers showed the highest heterozygosity rates, and D17S2228 and D17S2224 markers were the least informative in our analysis.

Low occurrence of occult hepatitis B virus infection and high frequency of hepatitis C virus genotype 3 in hepatocellular carcinoma in Brazil

Occult hepatitis B virus (HBV) infection has been reported among patients with hepatitis C virus (HCV) infection and hepatocellular carcinoma (HCC). Our aim was to evaluate the presence of occult HBV infection in patients with HCV-related liver cirrhosis (LC) with or without HCC in São Paulo, Brazil. Serum and liver tissue samples from 50 hepatitis B surface antigen-negative patients with HCV-related LC who underwent liver transplantation at the University of São Paulo School of Medicine Hospital from 1993 to 2004 were divided into groups with LC only (N = 33) and with LC plus HCC (N = 17). HBV DNA was assayed for serum and paraffin-embedded liver tissue (tumoral and non-tumoral) using real time PCR and only 1 case with HCC had HBV DNA-positive serum. All liver samples were negative. HCV genotype 3 was detected in 17/39 (43.7 percent) cases. In conclusion, using a sensitive real time PCR directed to detect HBV variants circulating in Brazil, occult hepatitis B infection was not found among HCV-positive cirrhotic patients and was rarely found among HCV-positive HCC patients. These results are probably related to the low prevalence of HBV infection in our population. Furthermore, we have also shown that HCV genotype 3 is frequently found in Brazilian cirrhotic patients, particularly when they also have HCC. More studies involving a large number of cases should be carried out to confirm these data and to further characterize Brazilian HCV genotype isolates to elucidate genetic features that might be related to its carcinogenic potential.

Low occurrence of occult hepatitis B virus infection and high frequency of hepatitis C virus genotype 3 in hepatocellular carcinoma in Brazil.

Occult hepatitis B virus (HBV) infection has been reported among patients with hepatitis C virus (HCV) infection and hepatocellular carcinoma (HCC). Our aim was to evaluate the presence of occult HBV infection in patients with HCV-related liver cirrhosis (LC) with or without HCC in São Paulo, Brazil. Serum and liver tissue samples from 50 hepatitis B surface antigen-negative patients with HCV-related LC who underwent liver transplantation at the University of São Paulo School of Medicine Hospital from 1993 to 2004 were divided into groups with LC only (N = 33) and with LC plus HCC (N = 17). HBV DNA was assayed for serum and paraffin-embedded liver tissue (tumoral and non-tumoral) using real time PCR and only 1 case with HCC had HBV DNA-positive serum. All liver samples were negative. HCV genotype 3 was detected in 17/39 (43.7%) cases. In conclusion, using a sensitive real time PCR directed to detect HBV variants circulating in Brazil, occult hepatitis B infection was not found among HCV-positive cirrhotic patients and was rarely found among HCV-positive HCC patients. These results are probably related to the low prevalence of HBV infection in our population. Furthermore, we have also shown that HCV genotype 3 is frequently found in Brazilian cirrhotic patients, particularly when they also have HCC. More studies involving a large number of cases should be carried out to confirm these data and to further characterize Brazilian HCV genotype isolates to elucidate genetic features that might be related to its carcinogenic potential.

Determinação do sexo do feto através de uma nova técnica não invasiva baseada em PCR / Determination of fetal sex by a new PCR method non invasive

A determinação do sexo do feto é geralmente realizada pelo procedimento de ultra-som que ocorre no segundo trimestre da gestação, sendo que, quando realizado antes da 13ª semana, esse método se mostra muito incerto.Técnicas moleculares utilizando o PCR já foram descrita, e possuem maior sensibilidade na determinação do sexo. Dentre estas técnicas existentes, as invasivas consistem em amniocentese ou coleta de amostra de vilo coriônico, seguida de PCR para determinar osexo e que representam em aumento de risco na gravidez e as técnicas não invasivas que conseguem detectar o DNA fetal no sangue periférico materno. Foi desenvolvida em nosso laboratório uma técnica capaz de detectar o sexo fetal nas primeiras semanas de gestaçãocom alto índice de acerto. A técnica consistiu em desenhar iniciadores que anelassem em regiões repetitivas espalhadas no cromossomoY e “PCR Nested” para aumentar a acurácia do exame. Os resultados demonstraram que a técnica possui sensibilidade e especificidade de 100%. Além disso, a PCR foi capaz de detectar em uma diluição seriada de uma amostra de DNA genômico masculina, previamente quantificada, a presença do cromossomo Y em amostrascontendo apenas 100 femtogramas de DNA.

The determination of fetal sex is currently carried out by ultrasound that is usually performed in the second trimester. However, it is inaccurate before 13th week of gestation. Molecular techniques such as PCR already had been described and were successful of fetal gender. Among these techniques, there are invasive methods: chorionic villus sampling and amniocentesis that are avoided because it is associated with a risk of fetal loss, and the non-invasive procedures that use of fetal DNA circulating in maternal blood. We report a new Nested PCR method with specific primers for repetitive sequences of the Y-chromossome. Our results indicated that sensitivity and specificity of the method were 100% and we can accurately detect Y-chromossome sequences in samples with only 100 femtograms of DNA template.