Paula Vieira Teixeira Vidigal

Prenatal toxoplasmosis diagnosis from amniotic fluid by PCR

Toxoplasmosis is one of the most common infections all over the world. Most cases are asymptomatic, except in immunosuppressed individuals and fetuses, which can be seriously damaged. Prenatal diagnosis should be made as soon as possible since treatment of the mother can minimize fetal sequelae. Our aim in this study was to test the polymerase chain reaction technique (PCR) in 86 samples of amniotic fluid from women who seroconverted during pregnancy. DNA was amplified using external primers and, in a second step, internal primers, in a nested PCR system. Samples were also inoculated into mice and the newborn were evaluated by T. gondii serology, skull x-ray, transfontanel ultrasound, fundoscopic examination, lumbar puncture and clinical examination. PCR was positive in seven cases and negative in 79. Among PCR-positive cases, two were negative by inoculation into mice and by clinical evaluation; among PCR-negative ones, three had clinical evidence of toxoplasmosis and one was positive after inoculation into mice. PCR showed values of sensitivity = 62.5% and specificity = 97.4%; the values of inoculation into mice where 42.9% and 100%, respectively. Although PCR should not be used alone for prenatal diagnosis of congenital toxoplasmosis, it is a promising method and deserves more studies to improve its efficacy.

Effects of sildenafil on the viability of random skin flaps.

PURPOSE To assess the viability of McFarlane skin flaps in rats with administration of sildenafil. METHODS Twenty Wistar rats were distributed into two groups: Control (dorsal skin flap, subdermal application of saline solution at 0.9%) and Study (dorsal skin flap, subdermal application of sildenafil). Seven days after the surgery, flaps were photographed and graphically rendered. Then, they were analyzed with AutoCAD software. Three biopsies (proximal, medial and distal) of each flap were collected for histological analysis. RESULTS Macroscopic analysis showed that animals of the study group had greater necrotic areas (p=0.003) in the dorsal skin flaps. Additionally, histological analysis of the distal third of these flaps showed a tendency to less granulated tissue formation in animals treated with sildenafil. CONCLUSION Sildenafil subdermally was associated with lower viability of the random skin flap in rats.

A thioacetamide-induced hepatic encephalopathy model in C57BL/6 mice: a behavioral and neurochemical study.

OBJECTIVE Hepatic encephalopathy (HE) is a neuropsychiatric syndrome resulting from liver failure. In the present study, we aimed to standardize an animal model of HE induced by thioacetamide (TAA) in C57BL/6 mice evaluating behavioral symptoms in association with liver damage and alterations in neurotransmitter release. METHOD HE was induced by an intraperitoneal single dose of TAA (200 mg/kg, 600 mg/kg or 1,200 mg/kg). Behavioral symptoms were evaluated using the SHIRPA battery. Liver damage was confirmed by histopathological analysis. The glutamate release was measured using fluorimetric assay. RESULTS The neuropsychiatric state, motor behavior and reflex and sensory functions were significantly altered in the group receiving 600 mg/kg of TAA. Biochemical analysis revealed an increase in the glutamate release in the cerebral cortex of HE mice. CONCLUSION HE induced by 600 mg/kg TAA injection in C57BL/6 mice seems to be a suitable model to investigate the pathogenesis and clinical disorders of HE.

Neurofibromatoses: part 1 ? diagnosis and differential diagnosis

Neurofibromatoses (NF) are a group of genetic multiple tumor growing predisposition diseases: neurofibromatosis type 1 (NF1), neurofibromatosis type 2 (NF2) and schwannomatosis (SCH), which have in common the neural origin of tumors and cutaneous signs. They affect nearly 80 thousand of Brazilians. In recent years, the increased scientific knowledge on NF has allowed better clinical management and reduced complication morbidity, resulting in higher quality of life for NF patients. In most cases, neurology, psychiatry, dermatology, clinical geneticists, oncology and internal medicine specialists are able to make the differential diagnosis between NF and other diseases and to identify major NF complications. Nevertheless, due to its great variability in phenotype expression, progressive course, multiple organs involvement and unpredictable natural evolution, NF often requires the support of neurofibromatoses specialists for proper treatment and genetic counseling. This Part 1 offers step-by-step guidelines for NF differential diagnosis. Part 2 will present the NF clinical management.

Schistosome-induced cholangiocyte proliferation and osteopontin secretion correlate with fibrosis and portal hypertension in human and murine schistosomiasis mansoni

Schistosomal egg antigens induce host bile ductular cells to proliferate and produce osteopontin (OPN), a pro-fibrogenic factor that stimulates hepatic stellate cells to become myofibroblasts. The numbers of OPN-producing bile ductules correlate with fibrogenesis and portal hypertension in humans and mice.

Spectrum of somatic EGFR, KRAS, BRAF, PTEN mutations and TTF-1 expression in Brazilian lung cancer patients.

Lung cancer is the leading global cause of cancer-related mortality. Inter-individual variability in treatment response and prognosis has been associated with genetic polymorphisms in specific genes: EGFR, KRAS, BRAF, PTEN and TTF-1. Somatic mutations in EGFR and KRAS genes are reported at rates of 15-40% in non-small cell lung cancer (NSCLC) in ethnically diverse populations. BRAF and PTEN are commonly mutated genes in various cancer types, including NSCLC, with PTEN mutations exerting an effect on the therapeutic response of EGFR/AKT/PI3K pathway inhibitors. TTF-1 is expressed in approximately 80% of lung adenocarcinomas and its positivity correlates with higher prevalence of EGFR mutation in this cancer type. To determine molecular markers for lung cancer in Brazilian patients, the rate of the predominant EGFR, KRAS, BRAF and PTEN mutations, as well as TTF-1 expression, was assessed in 88 Brazilian NSCLC patients. EGFR exon 19 deletions (del746-750) were detected in 3/88 (3·4%) patients. Activating KRAS mutations in codons 12 and 61 were noted in five (5·7%) and two (2·3%) patients, respectively. None of the common somatic mutations were detected in either the BRAF or PTEN genes. TTF-1 was overexpressed in 40·7% of squamous-cell carcinoma (SCC). Our findings add to a growing body of data that highlights the genetic heterogeneity of the abnormal EGFR pathway in lung cancer among ethnically diverse populations.

Occult hepatitis B virus infection in liver transplant patients in a Brazilian referral center

Estimates of occult hepatitis B virus (HBV) infection prevalence varies among different studies depending on the prevalence of HBV infection in the study population and on the sensitivity of the assay used to detect HBV DNA. We investigated the prevalence of occult HBV infection in cirrhotic patients undergoing liver transplantation in a Brazilian referral center. Frozen liver samples from 68 adults were analyzed using a nested polymerase chain reaction assay for HBV DNA. The specificity of the amplified HBV sequences was confirmed by direct sequencing of the amplicons. The patient population comprised 49 (72.1%) males and 19 (27.9%) females with a median age of 53 years (range=18-67 years). Occult HBV infection was diagnosed in three (4.4%) patients. The etiologies of the underlying chronic liver disease in these cases were alcohol abuse, HBV infection, and cryptogenic cirrhosis. Two of the patients with cryptic HBV infection also presented hepatocellular carcinoma. Markers of previous HBV infection were available in two patients with occult HBV infection and were negative in both. In conclusion, using a sensitive nested polymerase chain reaction assay to detect HBV DNA in frozen liver tissue, we found a low prevalence of occult HBV infection in cirrhotic patients undergoing liver transplant, probably due to the low prevalence of HBV infection in our population.

Association between Toll-like receptor and tumor necrosis factor immunological pathways in uterine cervical neoplasms

Introduction The immune system plays a critical role in the defense against human papillomavirus (HPV) infection and its persistence. Toll-like receptors (TLRs) are membrane receptors responsible for activation of the innate immune response, and an association between TLR expression and uterine cervical cancer has been shown. Tumor necrosis factors (TNFs) are among the main mediators of skin and mucosa inflammation. The aim of this study was to demonstrate the association between TLR and TNF immune expression and cervical cancer and premalignant cervical lesions. Methods A total of 64 embedded tissues were obtained from gynecological procedures, including 35 specimens with cervical intraepithelial neoplasia (CIN) and 10 specimens with cervical squamous cell carcinoma (CSCC) as well as 19 normal cervical samples. The expression of TLR2, TLR3, TLR4, TNF-α and TNF-β was measured by immunohistochemistry and graded into low and high levels of expression. Results There was an association between the expression levels of TLR2 and those of TNF-α and TNF-β (p = 0.01 and p = 0.021, respectively) in the cervical cancer and CIN groups. TLR4 expression was associated with TNF-α and TNF-β expression (p = 0.016 and p = 0.025, respectively) in these 2 groups. By contrast, TLR3 was not statistically associated with TNF-α or TNF-β in any of the groups. Conclusions There might be an association of the TLR2 and TLR4 pathways with the immunological response of TNF-α and TNF-β in cervical cancer. These markers are also expressed at higher levels in cervical cancer and premalignant lesions compared to normal controls.

EPIDEMIOLOGICAL ASPECTS OF HEPATOCELLULAR CARCINOMA IN A REFERRAL CENTER OF MINAS GERAIS, BRAZIL

CONTEXT Studies on epidemiology of hepatocellular carcinoma and modalities of therapy used to treat this condition are scarce in Brazil. Our aim was to characterize hepatocellular carcinoma according to etiology of the underlying chronic liver disease, and treatment modalities, in a referral center in Brazil. METHODS All cases of hepatocellular carcinoma registered in the Department of Pathology during a 12-year period (1998-2010) were included. Demographic data, etiology of the underlying liver disease and treatment performed were collected. RESULTS This case series included 215 patients, mean age 57.3 (±14.1) years, 164 (76.2 %) male. Virus C and virus B infection were detected in 88 (43%) and 47 (23%) patients, respectively. Ethanol abuse alone or combined with other etiologies was identified in 64 (32%) individuals. Schistosomiasis was found in 18 (9%) patients. Liver transplantation was the treatment of choice in 112 (51%) patients. This procedure was more frequently performed in hepatitis C virus-related hepatocellular carcinoma (70%) than B virus-related hepatocellular carcinoma (17%). Tumor resection was performed in 40 (18%) individuals, ethanol injection or thermo ablation in 18 (14%), and chemoembolization in 14 (7%). In 40 (19.4%) patients no treatment was performed and this percentage remained constant over the years. CONCLUSIONS Chronic hepatitis C, followed by ethanol abuse and chronic hepatitis B were the leading causes of underlying chronic liver disease associated with hepatocellular carcinoma. The results show a trend of increasing incidence of hepatocellular carcinoma; however, the proportion of untreated patients remained constant over the analyzed period.

p.F508del in a heterogeneous cystic fibrosis population from Minas Gerais, Brazil

Cystic fibrosis (CF) is the most common autosomal recessive disease of the Caucasian population. Among the various CF mutations, p.F508del is the most frequent, accounting for two-thirds of the global CF chromosomes, although showing great variability among populations. We have studied 115 unrelated CF patients from a mixed population of Minas Gerais (Brazil). To evaluate part of the DNA sequence of the cystic fibrosis transmembrane conductance regulator (CFTR) gene, blood DNA was obtained and PCR was performed using two pairs of primers that anneal to exons 10 and 24 of the CFTR gene. The PCR product was then submitted to automatic sequencing using the ABI PRISM 310 Genetic Analyzer. The p.F508del mutation was found in 50 (21.7%) of 230 unrelated CF alleles. Fifteen (13.0%) patients were homozygous for this mutation, while 20 (17.4%) were heterozygous; the remaining 80 (69.6%) patients did not carry the p.F508del mutation. Exon 24 sequence had no change in 75 (65.2%) patients, 21 (18.3%) had the sequence variation 4521G/A, 11 (9.6%) had a not yet described sequence variation 4407T/A and 8 (7.0%) patients had both sequence variations (4521G/A and 4407T/A). The polymorphism 4407T/A results in an amino acid modification from aspartic acid to glutamic acid, which will probably have no function effect in CFTR. This low p.F508del prevalence can be due to the variable ethnic origin of this population from Minas Gerais, which may have a high diversity of CF rare mutations.