José Moreno Barral

Trypanosoma cruzi in Persons without Serologic Evidence of Disease, Argentina

Current diagnosis of chronic Chagas disease relies on serologic detection of specific immunoglobulin G against Trypanosoma cruzi. However, the presence of parasites detected by polymerase chain reaction (PCR) in patients without positive conventional serologic testing has been observed. We determined the prevalence and clinical characteristics of persons with seronegative results for T. cruzi DNA detected by PCR in a population at high risk for chronic American trypanosomiasis. We studied a total of 194 persons from two different populations: 110 patients were recruited from an urban cardiology clinic, and 84 persons were nonselected citizens from a highly disease-endemic area. Eighty (41%) of persons had negative serologic findings; 12 (15%) had a positive PCR. Three patients with negative serologic findings and positive PCR results had clinical signs and symptoms that suggested Chagas cardiomyopathy. This finding challenges the current recommendations for Chagas disease diagnosis, therapy, and blood transfusion policies.

Prevalence of Circulating Trypanosoma cruzi Detected by Polymerase Chain Reaction in Patients With Chagas' Cardiomyopathy

Circulation 1997;95:2262–2270. 2. Kirklin JW. Combined aortic and mitral valve disease with or without tricuspid valve disease. In: Kirklin JW, ed. Cardiac Surgery. New York, NY: Churchill Livingstone, 1993:573–587. 3. Weyman AE. Left ventricular inflow tract I: the mitral valve. In: Weyman AE, ed. Principles and Practice of Echocardiography. Philadelphia, PA: Lea & Febiger, 1994:391–471. 4. Pini R, Roman MJ, Kramer-Fox R, Devereux RB. Mitral valve dimensions and motion in Marfan patients with and without mitral valve prolapse. Comparison to primary mitral valve prolapse and normal subjects. Circulation 1989;80:915–924. 5. Radermecker MA, Limet R. La classification fonctionelle des dysfonctions de la valvule mitrale selon Carpentier. Revue Medicale de Liege 1995;50:292–294. 6. Weyman AE. Principles of flow. In: Weyman AE, ed. Principles and Practice of Echocardiography. Philadelphia, PA: Lea & Febiger, 1994:184–201. 7. Devereux R, Reichek N. Echocardiographic determination of left ventricular mass in man. Circulation 1977;55:613–618. 8. Lowes BD, Gill EA, Rodriguez-Larrain J, Abraham WT, Bristow MR, Gilbert EM. Carvedilol is associated with a reversal of remodeling in chronic heart failure. Circulation 1996;94(suppl I):I-407. 9. Naik MM, Diamond GA, Pai T, Soffer A, Siegel RJ. Correspondence of left ventricular ejection fraction determinations from two-dimensional echocardiography, radionuclide angiography and contrast cineangiography. J Am Coll Cardiol 1995;25:937–942. 10. Tunick PA, Gindea AG, Kronzon I. Effect of aortic valve replacement for aortic stenosis on severity of mitral regurgitation. Am J Cardiol 1990;65:1219–1221. 11. Harris KM, Malenka DJ, Haney MF, Jayne JE, Hettleman B, Plehn JF Griffin BP. Improvement in mitral regurgitation after aortic valve replacement. Am J Cardiol 1997;80:741–774. 12. Adams PB, Otto CM. Lack of improvement in coexisting mitral regurgitation after relief of valvular aortic stenosis. Am J Cardiol 1990;66:105–107

Clinical significance of V617F mutation of the JAK2 gene in patients with chronic myeloproliferative disorders.

Abstract Objective: To determine the prevalence of JAK2 V617F mutation and its clinical correlation in patients with chronic myeloproliferative disorders (CMD): polycythemia vera (PV), essential thrombocythemia (ET) and idiopathic myelofibrosis (IMF). Materials and methods: Detection of JAK2 V617F mutation by allele specific-PCR. Results: One hundred and three patients with CMD were included in the study. JAK2 V617F distribution was PV 40/45 (89%), ET 30/43 (69%), and IMF 7/15 (47%). In PV and ET patients only, 18 had thrombosis at diagnosis and 12 during follow-up (these were microvascular: 11, venous: 7 and arterial: 12); of these 28/70 (40%) were JAK2pos versus 2/18 (11%) JAK2neg; P=0·02. In a median of 4 years, two patients with PV JAK2pos evolved to myelofibrosis and one patient with PV presented in leukemic transformation (JAK2pos before and after transformation); six patients died: four patients with IMF and two patients with PV. Conclusions: We found an association between JAK2 V617F and thrombotic events in patients with PV and ET.

Polymerase chain reaction procedure to detect Trypanosoma cruzi in blood samples from chronic chagasic patients

The feasibility of DNA amplification by the polymerase chain reaction for specific detection of Trypanosoma cruzi in human blood was investigated. We have used primers flanking a 220-bp fragment of highly repetitive elements, the E13 element, in T. cruzi nuclear DNA. Only polymerase chain reaction products from blood samples of chronic chagasic patients showed several amplified fragments in 1.6% agarose gels stained with ethidium bromide. Southern blot analysis demonstrated that the 220-bp amplified fragment is specific for T. cruzi DNA and very useful to detect the presence of the parasite in blood from chronic chagasic patients.

Determination of alkaline phosphatase isozymes in amniotic fluid

A simple method for the determination of the three isozymes of alkaline phosphatase (EC 3.1.3.1) contained in amniotic fluid (fetal intestinal, placental, and liver-bone-kidney) is presented. Total alkaline phosphatase activity was assayed in 10,000 g supernatants of amniotic fluid from 30 normal women between the 16th and 20th week of pregnancy. Electrophoretic patterns and inhibition by L-phenylalanine and L-homoarginine studies showed that all the fetal intestinal isozyme was precipitated in the pellet after centrifugation at 100,000 g for 90 min. Thus, the difference between total alkaline phosphatase activity and activity in the 100,000 g supernatant corresponds to fetal intestinal alkaline phosphatase. Placental isozyme can be determined by assaying alkaline phosphatase in the 100,000 g supernatant after heating at 56 degrees C for 90 min. Liver-bone-kidney isozyme activity is obtained by subtracting placental alkaline phosphatase activity from that of the 100,000 g supernatant. Mean percentages of the total alkaline phosphatase for each of the isozymes in amniotic fluid were 81% for fetal intestinal alkaline phosphatase, 7.5% for placental alkaline phosphatase and 12.0% for liver-bone-kidney alkaline phosphatase. Determination of fetal intestinal alkaline phosphatase by this method could be applied to the diagnosis of cystic fibrosis in fetuses having a 1:4 risk of being affected.