Heart transplantation in Chagas' disease. 10 years after the initial experience

BACKGROUND: Heart transplantation (HT) as a therapeutic option for end-stage chronic Chagas' heart disease (CCHD) is controversial. Reactivation of Trypanosoma cruzi infection and recurrence of the disease in the allograft are likely to occur. Furthermore, active myocarditis has been reported to predispose patients to an increased incidence and severity of rejection. METHODS AND RESULTS: We prospectively investigated the long-term follow-up of 10 patients with CCHD who underwent HT. Immunosuppression was based on cyclosporine A and azathioprine. T cruzi reactivation was prevented with benzonidazole. Besides allograft rejection surveillance, T cruzi infection was monitored through blood tests, myocardial biopsies, and serological tests. Over a mean follow-up period of 34 +/- 38 months (range, 73 to 124 months), 7 patients are alive and in NYHA functional class I. Life expectancy was 78% for the second year and 65% for 10 years. Rejection was less frequent in chagasic than in age- and sex-matched control patients (mean +/- SD, 1.60 +/- 1.26 versus 5.70 +/- 1.89 episodes per patient, respectively; P = .0001); decreased severity of rejection was also observed (P = .006). T cruzi parasitemias detected on three occasions were successfully treated with benzonidazole. There were no signs of recurrence of the disease in the allograft. CONCLUSIONS: These results suggest an important role of HT in the treatment of CCHD. There was a low frequency of T cruzi infection reactivation and no signs of recurrence of the disease in the allograft. The surprisingly decreased rejection incidence and severity require further studies for elucidation.     

Refactoring by Transformation

In this paper we present how refactoring of object-oriented programs can be accomplished by using refinement. Our approach is based on algebraic laws of an object-oriented language for refinement similar to Java. We follow a strategy involving data and algorithmic refinement of classes.     

Catalytic degradation of polyethylene over SAPO-37 molecular sieve

The degradation of high-density polyethylene (HDPE) was studied alone and in presence of silicoaluminophosphate type silicoaluminophosphate (SAPO-37) as catalyst. This material was synthesized by the hydrothermal method using tetrapropylammonium hydroxide and tetramethylammonium chloride as organic templates. The characterization by X-ray diffraction, infrared spectroscopy, thermogravimetry and scanning electron microscopy showed that typical faujasite structure for the SAPO-37 was obtained. The total acidity, determined by n-butylamine adsorption, it was equivalent to 0.558 mmol g⁻¹, corresponding to moderate acid strength. For catalytic reaction, a physical mixture of 25%SAPO-37/HDPE was decomposed in a thermobalance at heating rates of 5, 10 and 20 °C min⁻¹, from 380 to 520 °C. At the maximum degradation rate, the products were collected in a cold trap and analyzed by a coupled gas chromatograph/mass spectrometer. The degradation of HDPE without catalyst was carried out at the same conditions for comparison with the obtained data with SAPO-37. The HDPE alone suffers decomposition to a wide range of hydrocarbons (C₅–C₂₅) while in the presence of catalyst, light hydrocarbons (C₂–C₁₂) were obtained. By the application of the Vyazovkin model-free kinetic method, it was observed that the activation energy decreased from 290 kJ mol⁻¹ for HDPE alone, to 220 kJ mol⁻¹ for 25%SAPO-37/HDPE, evidencing that SAPO-37 is an effective catalyst for polyethylene degradation.     

Antibody isotypes, including IgG subclasses, in Ecuadorian patients with pulmonary paragonimiasis

An ELISA test was developed to detect Paragonimus-specific antibodies, including IgG subclasses, using P. mexicanus crude water-soluble antigens. The test was standardized to detect antibodies in sera of Ecuadorian patients with pulmonary paragonimiasis and negative controls from the endemic area. The detected mean levels of IgG (0.753, SEM: 0.074) and IgM (0.303, SEM: 0.033) were significantly elevated (P < 0.05). Within the IgG subclasses, IgG4 showed the highest detected mean level (0.365, SEM: 0.116) and the other three subclasses showed considerably lower mean levels (IgG1, 0.186 SEM: 0.06; IgG2, 0.046 SEM: 0.01; IgG3, 0.123 SEM: 0.047). The number of P. mexicanus eggs found in sputum of infected individuals showed a positive correlation with the level of antibodies detected for IgM, IgG and its subclasses (P < 0.001). The relevance of these findings in Ecuadorian patients suffering from pulmonary paragonimiasis is discussed.     

Partial nephrectomy in cancer of the upper pole of kidney. Anatomical bases

On the basis of their importance for nephron-sparing surgery in tumors of the superior pole of the kidney, we analyzed 3-dimensional endocasts of the intrarenal structures. In 86.6% the superior pole was related to 3 arteries involved in its resection. Management of the superior (apical) segmental artery is in general simple as well as the ligature of the artery related to the anterior surface of the upper infundibulum. Ligature of the branch of the posterior segmental artery, that is related to the upper infundibulum, is critical due to the risk of injuring this segmental artery with loss of a great portion of renal parenchyma. The posterior segmental artery (retropelvic artery) is involved and must be preserved in all cases of superior pole resection. A retropelvic vein with its upper dorsal plexus was present in 69% of the cases. This vein must be previously ligated to provided safe management of the arteries during superior pole resection.     

Geometric properties of central catadioptric line images and their application in calibration

In central catadioptric systems lines in a scene are projected to conic curves in the image. This work studies the geometry of the central catadioptric projection of lines and its use in calibration. It is shown that the conic curves where the lines are mapped possess several projective invariant properties. From these properties, it follows that any central catadioptric system can be fully calibrated from an image of three or more lines. The image of the absolute conic, the relative pose between the camera and the mirror, and the shape of the reflective surface can be recovered using a geometric construction based on the conic loci where the lines are projected. This result is valid for any central catadioptric system and generalizes previous results for paracatadioptric sensors. Moreover, it is proven that systems with a hyperbolic/elliptical mirror can be calibrated from the image of two lines. If both the shape and the pose of the mirror are known, then two line images are enough to determine the image of the absolute conic encoding the camera's intrinsic parameters. The sensitivity to errors is evaluated and the approach is used to calibrate a real camera.