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.     

A Mg-dependent ecto-ATPase is increased in the infective stages of<Emphasis Type="Italic"> Trypanosoma cruzi</Emphasis>

In this work, we describe the ability of living epimastigotes of Trypanosoma cruzi to hydrolyze extracellular ATP. In these intact parasites, there was a low level of ATP hydrolysis in the absence of any divalent metal (2.42±0.31 nmol Pi/h×10⁸ cells). ATP hydrolysis was stimulated by MgCl₂, and the Mg-dependent ecto-ATPase activity was 27.15±2.91 nmol Pi/h×10⁸ cells. The addition of MgCl₂ to the extracellular medium increased the ecto-ATPase activity in a dose-dependent manner. This stimulatory activity was also observed when MgCl₂ was replaced by MnCl₂, but not by CaCl₂ or SrCl₂. The apparent K_m for Mg-ATP^2– was 0.61 mM, and free Mg²⁺ did not increase the ecto-ATPase activity. This ecto-ATPase activity was insensitive to the inhibitors of other ATPase and phosphatase activities. To confirm that this Mg-dependent ATPase was an ecto-ATPase, we used an impermeant inhibitor, DIDS (4, 4.diisothiocyanostylbene 2-2-disulfonic acid) as well as suramin, an antagonist of P₂ purinoreceptors and inhibitor of some ecto-ATPases. These two reagents inhibited the Mg²⁺-dependent ATPase activity in a dose-dependent manner. A comparison among the Mg²⁺-ecto-ATPase activities of the three forms of T. cruzi showed that the noninfective epimastigotes were less efficient at hydrolyzing ATP than the infective trypomastigote and amastigote stages.     

Trends of accuracy of clinical diagnoses of the basic cause of death in a university hospital

AIMS: To determine the agreement between clinical and necropsy diagnoses of the basic cause of death, and to compare the results with those obtained in a previous study carried out at the same university hospital. METHODS: In total, 4828 necropsies, performed between 1990 and 1995 in the University Hospital of the Faculty of Medicine of Ribeir?o Preto, University of S?o Paulo, Brazil, were reviewed. Examinations were concluded at the macroscopic part of the necropsy in nearly 35% of the cases. Statistical analysis was carried out using the kappa coefficient comparing the clinical diagnosis and the diagnosis obtained after necropsy. The jackknife method was used to identify comparable kappa values for the comparison of the two periods. RESULTS: Compared with the 1978-80 period, a significant increase in diagnostic agreement was seen for the group submitted to complete necropsy, whereas no similar increase was detected when only the macroscopic step was analysed. CONCLUSIONS: There was a discrete tendency to an improved correlation between clinical and postmortem data stated by full necropsy analysis. The findings show that microscopic analysis remains important to confirm the cause of death in many cases. Diagnostic discrepancies remained high, and therefore complete necropsy continues to be an essential instrument for the assessment of clinical diagnosis.     

Cardiorespiratory fitness and body mass index values in 9-year-old rural Norwegian children

Aim: To describe cardiorespiratory fitness and body mass index (BMI) values in a representative population of 9-year-old Norwegian children in two rural communities and compare present values with previous findings.
Methods: Two hundred and fifty-nine 9-year-old children were invited, and 256 participated in this study. Maximal oxygen uptake was directly measured during a continuous progressive treadmill protocol. Body mass and height were also measured.
Results: The mean ± SD relative maximal oxygen uptake was 52.8 ± 6.5 for boys and 46.9 ± 7.2 mL/kg/min for girls. Eight percent of the boys and 16.8% of the girls were classified as overweight, and 1.6% of the boys and 6.9% of the girls as obese. Mean age, body mass, height and Ponderal index were not significantly different between sexes. Girls had a higher BMI than boys (p = 0.05).
Conclusion: Compared to earlier Norwegian studies, children's BMI values seem to have increased substantially. This increase is most pronounced in girls. When assessing these differences using the PI, this increase is less marked. Comparing maximal oxygen uptake data with that in earlier Nordic studies, there is no evidence that fitness has declined among 9-year olds. However, the limitations of the few earlier studies make reliable comparisons difficult.     

Cytological criteria to predict basal phenotype of breast carcinomas

Breast carcinoma is a heterogeneous disease. It can be classified into phenotypes based on the expression of certain proteins, with distinct differences in prognosis. The basal phenotype is associated with worse prognosis and it still remains without specific treatment. However, there is currently no international consensus on the cytological criteria that could predict this phenotype. The purpose of the study was to evaluate the cytological criteria in fine‐needle aspiration biopsy and to identify their association with the basal phenotype of breast carcinoma. Fine‐needle aspiration biopsy specimens and tissue sections (mastectomy specimen) from 74 cases of high‐grade invasive ductal breast carcinomas were consecutively retrieved from the files of three institutions. Breast carcinomas were studied using the tissue microarray technique, being classified into phenotypes: luminal A, luminal B, HER2 overexpression, and basal. The cytological criteria for all cases were reviewed blindly by two pathologists according to five cytological criteria: cellularity, cell pattern, presence of necrosis, nucleoli, and nuclear atypia. Exact Fisher test was used to test the association between cytological criteria and the phenotypes of breast carcinoma. Necrosis was present in 64.7% of basal breast carcinomas, and 31.1% of nonbasal breast carcinomas, and that result was statistically significant, showing an odds ratio (OR) of 3.80. The basal phenotype, compared with the luminal A, showed more necrosis (OR = 6.97), present/prominent nucleoli (OR = 8.18), and cellularity more frequently (OR = 18.03). Necrosis, as well as present/prominent nucleoli and abundant cellularity are criteria more frequently associated to the basal phenotype of breast carcinoma. Diagn. Cytopathol. 2009. © 2009 Wiley‐Liss, Inc.     

Antenatal diagnosis of a choledocal cyst

Choledocal cyst is a rare anomaly that usually becomes symptomatic during childhood. Forty to sixty percent of choledocal cysts are diagnosed before 10 years old, usually when complications occur. Today, because of advances in sonographic imaging, some cysts can de diagnosed before birth. The major prognostic factor is the development of complications such as hepatic fibrosis. Early treatment, after postnatal ultrasonography assessment, can reduce the incidence of serious complications. The authors report a case of a choledocal cyst diagnosed at 23 weeks gestation.     

Hemoglobinopathies in newborns from Salvador, Bahia, Northeast Brazil

Hemoglobinopathies are hereditary disorders of the hemoglobin molecule with a high prevalence worldwide. Brazil has a prevalence of 0.1 to 0.3% of newborns with sickle cell anemia and 20.0 to 25.0% of heterozygous alpha2 thalassemia among African Brazilians. In the present study, we investigated the presence of variant hemoglobins and alpha2(3.7 Kb) and alpha2 (4.2 Kb) thalassemia in newborns from Salvador, Bahia, Brazil. Samples of umbilical cord blood from a total of 590 newborns were analyzed, of which 57 (9.8%) were FAS; 36 (6.5%) FAC; one (0.2%) SF; and five (0.9%) FSC. One hundred fourteen (22.2%) newborns had alpha2(3.7 Kb) thalassemia, of whom 101 (19.7%) were heterozygous and 13 (2.5%) homozygous, showing statistical significance for hematological data between newborns with normal alpha genes and alpha2(3.7 Kb) thalassemia carriers. The alpha2(4.2 Kb) thalassemia was not found. Frequencies found in the present study confirm that hemoglobinopathies are a public health problem in Brazil, emphasizing the need for neonatal screening and genetic counseling programs.