[Anatomic reconstruction of native coronary arteries and vein graft with less shortening wallstent]. / Reconstrução anatômica das artérias coronárias nativas e das pontes de safena utilizando less shortening wallstent.

PURPOSE: To evaluate the advantage of the wallstent in the treatment of long or multiple lesions. METHODS: Thirty eight patients with mean age 66 years underwent wallstent implantation. Fourteen had lesions in the left anterior descending, 12 in the right coronary, nine in the circumflex and four in a vein graft. The technique for implantation requires an accurate quantification of the vessel diameter, because the chosen stent should be 1.5 mm larger than the target vessel. A new technique using additional inflations with high pressure balloons was applied. RESULTS: Successful implantation occurred in 95%. We did not have success in two patients. One of them due to damage in the stent and the other to unsuccessful liberation. Both patients were submitted to conventional angioplasty without complications. CONCLUSION: The wallstent implantation can be successfully performed with high success rate, but late angiographic results still demand further studies.

A flow-cell optosensor for lead based on immobilized dithizone.

Dithizone immobilized on XAD-4 resin has been studied as a sensor element of an optical sensor for lead using a flow-cell. Using this arrangement, lead in solution has been determined in the concentration range 1 x 10(-5)-3 x 10(-7)M with a detection limit of 1 x 10(-8)M(i.e., 2 mug/l.). The standard deviation of the method for the measurement of lead at a concentration of 1 x 10(-6)M was found to be 7%. The response of the sensor was reproducible and can be regenerated using 0.01M hydrochloric acid followed by citrate-hydroxylamine solution.

Determination of calcium and magnesium in limestone and dolomite by enthalpimetric flow-injection analysis.

A flow-enthalpimetric method for the determination of calcium and magnesium in limestone and dolomite is described. Calcium is determined by measuring the heat evolved from the substitution reaction with Mg-EDTA. The amount of magnesium is calculated from the calcium content and the enthalpimetric signal for the reaction of the sample solution with disodium-EDTA, which gives the total concentration of calcium and magnesium. Analysis of reference materials and other samples indicates an error not exceeding 0.3% of CaO and MgO, and a sampling rate of 100 samples per hour.

Determination of water in ethanol and acetone by direct injection enthalpimetry based on the heat of dilution.

Two analytical procedures based on the magnitude of the heat of dilution and direct injection enthalpimetry have been developed for determination of water in ethanol and acetone. The results obtained by means of the heat of dilution were compared with the values given by pycnometry, and gave a relative difference in the range 0.2-3%. The precision depends on the slope of the calibration curve, which varies with the procedure and the concentration of the sample.

Determination of carbohydrates by direct injection enthalpimetry.

An analytical method for the determination of carbohydrates is described, which is based on the enthalpimetric signal obtained at the beginning of the reaction with periodate. The apparatus is described and relevant aspects of the procedure are discussed. Single carbohydrates can be determined in a few minutes with a precision of 1%. Analysis of mixtures of glucose and fructose is reported.