Optimisation and characterisation of marihuana extracts obtained by supercritical fluid extraction and focused ultrasound extraction and retention time locking GC-MS.

The optimisation of focused ultrasound extraction and supercritical fluid extraction of volatile oils and cannabinoids from marihuana has been accomplished by experimental design approach. On the one hand, the focused ultrasound extraction method of volatile compounds and cannabinoids was studied based on the optimisation of cyclohexane and isopropanol solvent mixtures, and the instrumental variables. The optimal working conditions were finally fixed at isopropanol/cyclohexane 1:1 mixture, cycles (3 s(-1)), amplitude (80%) and sonication time (5 min).

[The long-term follow-up of 1000 patients with a valve replacement by the prosthesis of the Instituto Nacional de Cardiología Ignacio Chávez].

The long-term follow-up of patients with bioprosthetic valves manufactured at the Instituto Nacional de Cardiología Ignacio Chávez is presented. From February 1983 to May 1990, 1068 patients were operated and 1252 valves were replaced. Eighty two percent had rheumatic heart disease with one or more injured valves.

[Heart valves (anatomo-pathologic study of 1139 cases].

We review the pathological specimens sent to the Pathology Department from January 1983 to June 1988 that belonged to 7567 patients. For this study we have selected specimens from 1139 patients (15.05% of the total), who were submitted to valvular replacement surgery.

[Manufacture of valvular prostheses from bovine pericardium, their evaluation and the initial results of the 1st group of implants].

The results obtained with some types of bioprostheses together with the present economical situation of the country pointed out that the manufacture of another type of bioprostheses was necessary. After a careful analysis of the results that had been reported in the literature with the diverse types of bioprostheses had been made, it was concluded that pericardial valves were the best choice for our specific requirements. The first problem that had to be solved was the identification of the adequate fraction of purified glutaraldehyde that would provide for adequate tissue fixation.