Percutaneous transluminal coronary angioplasty in unstable and stable angina pectoris: a comparison of immediate success and complications.

To determine the success rate and the safety of percutaneous transluminal coronary angioplasty in patients with unstable angina pectoris (group 1) versus stable angina (group 2), we studied 299 consecutive patients who underwent coronary angioplasty of 373 consecutive lesions. Of these patients, 149 had unstable angina pectoris and dilation of 188 arteries. The success rate was high and similar in both groups (95 and 93%, respectively). The groups did not differ in regard to the lesion characteristics, vessels and number of sites dilated except for an increase in the presence of thrombus in the unstable angina group (p < 0.03). Although there was a higher incidence of coronary thrombus and more acute myocardial infarction in group 1, the major complication rate did not differ from that of group 2 and was low in both of them (3 and 2%, respectively). No deaths occurred. Six patients (3 in each group) needed urgent coronary artery bypass grafting while 3 additional patients developed acute Q-wave myocardial infarction (all of them in group 1). Thus, percutaneous transluminal coronary angioplasty is a safe and successful procedure in patients with unstable angina as well as in patients with stable angina pectoris.     

The pharmacokinetics of (125I) 3-deoxy-3-iodine glucose on experimental tumor modelsin Vivo

The dynamics of¹²⁵I distribution is studied in rats with induced tumors of the prostate and mammary gland for intravenous administration of¹²⁵I-3D-G. It is found that 80% of the activity is eliminated in the first 24 hours. A relatively high level of¹²⁵I accumulation is found in necrotically altered regions of the tumor. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 117, № 3, pp. 294–295, March, 1994.     

Effects of rapid volume expansion on the right filling pressures after prosthetic valve surgery.

The effects of rapid intravascular volume expansion were studied in 12 patients, 4 to 14 years after single prosthetic heart valve replacement. The data observed showed a statistically significant mean difference before and after volume expansion of right atrial mean pressure and right ventricular end diastolic and pulmonary capillary pressures. However, right atrial and pulmonary capillary pressures equilibration was not detected. The right atrial pressure form showed abnormal variations during inspiration. Dip and plateau right ventricular diastolic pressure configuration was recorded in 6 patients after expansion, was absent in 2 and questionable in 4. A deep Y descent with an M-shaped right atrial pressure form was recorded in all 12 patients. The explanation for these phenomena is unclear. Thus, in the absence of pressure equilibration and clinical evidence of constriction, the abnormalities recorded during rapid volume expansion should be cautiously interpreted.     

Disorders of the hemodynamics and myocardial structure in patients with infectious-allergic myocarditis complicated by heart failure

A study of 30 patients with infectious-allergic myocarditis, accompanied with chronic heart failure made use of echocardiography, hemodynamic assessment by cardiac catheterization, endomyocardial biopsy. A relationship is demonstrated between hemodynamic changes and the lesion of cellular ultrastructural apparatus, mitochondria, in particular. Patients with first-stage heart failure associated with infectious-allergic myocarditis showed incomplete diastole, while systolic changes were found in patients with severe manifestation of circulatory insufficiency.     

Study of the drug release mechanism from tyrphostin AG-1295-loaded nanospheres by in situ and external sink methods.

The present study focused on in vitro release of polylactide-nanoencapsulated tyrphostin AG-1295, a potential agent for local therapy of restenosis. The drug was formulated in matrix-type nanoparticles, termed nanospheres (NS) using the nanoprecipitation method. AG-1295 is a model for low-molecular weight lipophilic compounds, the release behavior of which cannot be adequately characterized by existing methods. An in vitro release technique suitable for optimizing the nanoparticulate formulation release behavior was developed through a novel external sink method and an in situ release method utilizing the environmental sensitivity of the AG-1295 fluorescence spectrum. Similar tendencies were demonstrated by both methods in drug release studied as a function of selected NS preparation variables. The release properties of the drug fractions varying in their binding mode to the carrier particles were studied by the external sink method. The NS surface-adsorbed drug exhibited a significantly higher release rate compared to the drug entrapped in the polymeric matrix. The in situ release of the encapsulated drug was analyzed using the diffusion models of release from a matrix-type sphere. The release was shown to be a composite process, with a burst phase attributed largely to the rapid dissociation of the surface-bound AG-1295. The diffusion-controlled phase exhibited an alteration in kinetic pattern obviously due to the drug distribution between polymeric matrix compartments differing in their permeability. Drug in vitro release investigation may be effectively used to characterize the drug-carrier interaction and internal carrier structure in nanoparticulate formulations, as well as optimize the release behavior in respect to their therapeutic application.     

Study of the molecular structure of ethylene-propylene copolymers obtained with catalysts of different composition

The monomer composition and sequence distribution in ethylene-propylene copolymers (EPCs) obtained with supported titanium/magnesium (TMC) and vanadium/magnesium (VMC) catalysts as well as with titanium trichloride was studied by means of ¹³C NMR spectroscopy. Based on these data ethylene-propylene reactivity ratios were determined. The EPCs obtained on these catalysts are inhomogeneous in composition; the soluble fractions contain larger amounts of propylene. The microstructures of copolymers obtained on TMCs and TiCl₃ are similar. For EPCs obtained on VMCs, propylene “head-to-head” or “tail-to-tail” inversions and a more homogeneous distribution of propylene are observed.     

Molecular-weight distribution in the activated-monomer polymerization of ethylene oxide. Mechanistic implications

The mechanism of the activated-monomer polymerization of ethylene oxide catalyzed by protic acids was investigated by means of an analysis of the molecular-weight distribution curves from the polymers obtained. The results suggest that polymer ether groups participate in the polymerization by forming hydrogen-bonded complexes and tertiary oxonium cations in the reaction with the activated monomer, both being intermediates of the propagation reactions.