Microsatellite loci: determining the genetic variability of Plasmodium vivax

Objective To describe the genetic diversity of Plasmodium vivax isolates from different areas in the Brazilian Amazon using 11 polymorphic microsatellites and to evaluate the correlation between microsatellite variation and repeat array length. Methods Microsatellites with variable repeat units and array lengths were selected using in silico search of the P. vivax genome. We designed primers and amplified the selected loci in DNA obtained from patients with P. vivax acute infections. Results Positive correlation between repeat array length and microsatellite variation was detected independently of the size of repeat unit (di, tri, or tetranucleotide). We used these markers to describe the genetic variability of P. vivax isolates from four geographic regions of the Brazilian Amazon. Substantial variability was observed among P. vivax isolates within populations, concurrent with high levels of multiple‐clone infections and high linkage disequilibrium. Overall, structured populations were observed with moderate to high genetic differentiation. Conclusion The markers studied are useful tools for assessing population structure of P. vivax, as demonstrated for Brazilian populations and for searching for evidence of recent selection events associated with different phenotypes, such as drug resistance.     

Prediction of significant liver fibrosis in kidney transplant patients with chronic hepatitis C virus infection: the TX‐3 index

Summary. HCV infection is highly prevalent among kidney transplant (KT) recipients. The natural history and management of these patients are controversial. We sought to assess the diagnostic value of noninvasive markers of liver fibrosis in KT HCV‐infected patients. This cross‐sectional study included 102 KT individuals with positive HCV‐RNA. Bivariate and multivariate analyses were used to identify variables associated with significant fibrosis (METAVIR ≥ F2). Significant fibrosis was observed in 20 patients (20%). Time after transplantation, AST level, and platelet count were identified as independent predictors of significant fibrosis. Based on the regression model, a simplified index was devised. The AUROC for the TX‐3 model was 0.867 ± 0.081 (0.909, when adjusted by DANA). Values ≤4.0 of TX‐3 showed a NPV of 97% and scores >9.6 exhibited a PPV of 71%. If biopsy indication was restricted to scores in the intermediate range of TX‐3, this could have been correctly avoided in 68% of cases. The APRI score provided a correct diagnosis in only 47 individuals (46%) and exhibited lower diagnostic indices for both cutoffs, as compared to the TX‐3 index. Comparison of AUROCs showed a trend towards superior diagnostic accuracy for TX‐3 over APRI, although the difference between AUROCs did not reach statistical significance (0.867 ± 0.053 vs 0.762 ± 0.066, respectively, P = 0.064). In conclusion, significant liver fibrosis can be reliably predicted in KT HCV‐infected subjects by simple and widely available parameters. If additional studies confirm our results, this model might obviate the requirement for a liver biopsy in a significant proportion of those patients.     

Signal to cut-off (S/CO) ratio and detection of HCV genotype 1 by real-time PCR one-step method: is there any direct relationship?

BackgroundPolymerase chain reaction (PCR) methods play an essential role in providing data related to diagnosis, monitoring and treatment of hepatitis C virus (HCV) infection. EIA results are reported as “reactive” or “non reactive” and EIA S/CO ratio may also be reported as “high” or “low.” This study aimed to evaluate the performance of a real-time RT-PCR and assess whether there is relationship between S/CO and PCR results.Study Design and MethodsSera from blood donors were analyzed by Enzyme-Linked Immunosorbent Assay (ELISA) and RT-PCR assay to detect HCV infection.ResultsThe RT-PCR assay to genotypes 1a/b showed an acceptable linear response in serial dilutions. The samples were divided into two groups based on their serological results: group A – S/CO ratio < 3 (60 samples) and group B – S/CO ratio > 3 (41 samples). Viral loads were confirmed positive in group B samples in 90%, and in group A samples were confirmed positive in only 13% by RT-PCR.ConclusionThe methodology used was able to detect the presence of RNA-HCV genotype I in 90% of the samples serologically positive in group B. All negative samples were sent to search for other genotypes of HCV (genotypes 2-6) and were confirmed as negative. These data suggests that these negative samples may have HCV RNA viral load below the detection limit of our test (310 IU/ mL), or a false positive result in serological test, or spontaneous viral clearance occurred.     

Secretory phospholipase A2 in patients with coronary artery disease

This study investigated the correlation of sPLA2 (secretory phospholipase A2) activity with the atheromatosis extent in subjects with coronary artery disease (CAD) undergoing coronary angiography. We analyzed 123 patients, including 35 subjects with angiographically normal coronary arteries (controls), 31 with mild/moderate atheromatosis (stenosis of 30–70% of the luminal diameter in one or more coronary arteries) and 57 with severe atheromatosis (>70% stenosis). Plasma sPLA2 activity was significantly higher in subjects with severe [127.7 U/ml (102.3–162.7); p < 0.0001] and mild/moderate [112.0 U/ml (100.6–146.9); p < 0.0001] atheromatosis than in controls [19.8 U/ml (15.1–32.1)]. In a multiple logistic regression model, adjusted for age, gender, body mass index, tabagism, hypertension, sedentarism, family history for coronary artery disease, diabetes mellitus, total cholesterol, HDLc, LDLc, triglycerides, high sensitivity C-reactive protein and phospholipase A2, only sPLA2 was observed to be independently associated with severe CAD (>70% of stenosis) (p < 0.0001).     

Food Intolerance,Diet Composition,and Eating Patterns in Functional Dyspepsia Patients

The aims of this study are to investigate dietary factors, food intolerance, and the body mass index data, as an indicator of nutritional status, in functional dyspepsia patients. Forty-one functional dyspepsia patients and 30 healthy volunteers answered a standardized questionnaire to identify eating habits and food intolerance, and then completed a 7-day alimentary diary. There was no significant difference in daily total caloric intake between patients and controls. Patients associated their symptoms with the ingestion of several foods, but in general maintained their regular intake, with the exception of a small reduction in the proportion of fat in comparison with controls (median 28 vs. 34%; P = 0.001). No patient was underweight. In conclusion, our results suggest that food intolerance has no remarkable influence on food pattern and nutritional status in most functional dyspepsia patients. Further studies are necessary to clarify the role of fat in the generation of dyspeptic symptoms.     

T-lymphocytic infiltrate in canine mammary tumours: clinic and prognostic implications

In recent years, considerable progress has been made in understanding the role of the immune system in tumour progression. However, in canine mammary tumours (CMT), the prognostic value of T-lymphocytes is not established. The aims of the present study were to characterize T-lymphocytic infiltrate in 57 canine mammary tumours (21 benign and 36 malign), by immunohistochemical detection of CD3 antigen, and to determine its association with several clinicopathological parameters and overall survival. CD3+ positive cells were counted in 10 high-power fields within the tumour (i.e. The tumour-infiltrating T-lymphocytes, TIL), in the peripheral area of the tumour and in the adnexal non-tumoural mammary gland. CD3(+) TILs were significantly more frequent in benign than in malignant tumours (p<0.001). Conversely, peripheral CD3(+) TILs were significantly more frequent in malignant than in benign neoplasias (p<0.001). For CD3(+) T-lymphocytes in the adnexal non-tumoural mammary gland, there was no statistical difference in their frequency between benign and malignant tumours. On survival analysis, there was a tendency towards an association of a higher number of CD3(+) TILs and a shorter overall survival (p=0.08). Interestingly for CD3(+) T-lymphocytes in the adnexal non-tumoural mammary gland, a statistically significant relationship was observed, with a higher number of lymphocytes conferring a reduced overall survival (p=0.045). Further studies will be required to better understand the biological implications of the current findings.     

Canine mammary tumours as a model to study human breast cancer: most recent findings

Clinical and molecular similarities between canine mammary tumours and human breast cancer have been described in recent decades. Clinically, the similarities are very strong: spontaneous tumours, hormonal aetiology, age of onset and an identical course of the disease. The clinical characteristics that have an impact on the clinical outcome are also identical: tumour size, lymph node invasiveness and clinical stage. Nowadays, as far as human medicine is concerned, the goal is to identify prognostic factors, mainly at the molecular level, such as those involved in metastasis, which could be used as therapeutic targets to support a better outcome. Moreover, in this area, canine mammary tumours seem to mimic human breast cancer, as a range of similarities are found at the molecular level concerning the overexpression of steroid receptors, proliferation markers, epidermal growth factor, p53 supressor gene mutations, metalloproteinases, cyclooxygenases, among many others. Clinical and molecular data that support canine mammary tumours as a model to study human breast cancer are analysed in this review. Additionally, it is shown that some recent molecular targets in canine mammary tumours may be seen as indicators for similar research to be performed in the corresponding human disease.