Study of Human Fibrinogen Oxidative Modification using Differential Scanning Calorimetry.

For the first time, with the aid of differential scanning calorimetry, the thermal denaturation of fibrinogen under induced oxidation was studied. All fibrinogen structural elements detected by DSC (D region, αC-domain, and E region) are subjected to oxidation. Structural changes in fibrinogen molecule were characterized by the denaturation temperature, denaturation enthalpy, and van't Hoff enthalpy.

Modification of human serum albumin under induced oxidation.

For the first time, by using the complex of physicochemical methods (mass-spectrometry, differential scanning calorimetry, spectrofluorimetry, method of spectral and fluorescent probes, dynamic light scattering, and UV spectrophotometry), the oxidation-mediated modification of chemical and spatial structure of albumin has been studied. All albumin structural regions are subjected to oxidation, methionine and aromatic amino acids primarily involved in oxidation. The albumin melting shows a decrease in thermal stabilization of the structure and changing of aggregation upon oxidation. The change in physical and chemical properties of albumin under different quantity of the oxidizer has been analyzed.

Resistance of alpha-crystallin quaternary structure to UV irradiation.

The damaging effect of UV radiation (lambda > 260 nm) on bovine alpha-crystallin in solution was studied by small-angle X-ray scattering, gel permeation chromatography, electrophoresis, absorption and fluorescence spectroscopy, and differential scanning calorimetry. The results obtained show that damage to even a large number of subunits within an alpha-crystallin oligomer does not cause significant rearrangement of its quaternary structure, aggregation of oligomers, or the loss of their solubility. Due to the high resistance of its quaternary structure, alpha-crystallin is able to prevent aggregation of destabilized proteins (especially of gamma- and beta-crystallins) and so to maintain lens transparency throughout the life of an animal (the chaperone-like function of alpha-crystallin).

Some physico-chemical and thermodynamic characteristics of maize starches hydrolyzed by glucoamylase.

Glucoamylolysis of maize starch at 55 °C has been studied by means of scanning electron microscopy (SEM), wide-angle X-ray diffraction spectroscopy (WAXD), and differential scanning calorimetry (DSC). It was found that hydrolysis is accompanied by changes in thermodynamic parameters of diluted aqueous dispersions of partially hydrolyzed starches. Such changes are ensured by two processes directly from hydrolysis and accompanying annealing. At relatively low degrees of hydrolysis (less than 30%), changes in thermodynamic parameters are mainly controlled by annealing. At the same time, at high degrees of hydrolysis (more than 40%), the main contribution to changes in thermodynamic parameters of partially hydrolyzed starch granules is due to the hydrolysis itself. It has been established that the main controlling parameter is the thickness of crystalline lamellae Lcrl, which, when annealed, increases, but tends to decrease at deeper glucoamylolisis. It has been established that the thickness Lcrl of crystalline lamellae, which increases with annealing, but shows a tendency to decrease with deeper glucoamylolysis is the most representative parameter of changes in maize starch after hydrolysis.

Merits of stress thallium-201 myocardial perfusion imaging in patients with inconclusive exercise electrocardiograms: correlation with coronary arteriograms.

Stress thallium-201 myocardial perfusion images were obtained in 65 patients with an inconclusive exercise electrocardiogram. All 65 patients underwent coronary angiograpic studies. The exercise electrocardiogram was judged inconclusive in 35 patients (54 percent) because submaximal exercise had been performed and in 30 patients (46 percent) who manifested ST-T segment abnormalities at rest. Exercise thallium-201 myocardial perfusion images were abnormal in 20 patients and normal in 45. Nineteen (95 percent) of the 20 patients with abnormal exercise images had severe disease of one or more major coronary arteries. Thirty-seven (82 percent) of the 45 patients with normal exercise images had no significant coronary artery disease; the remaining 8 patients had coronary artery disease. Therefore, 19 of 27 patients with coronary artery disease had abnormal exercise images (sensitivity 70 percent), and 37 of 38 patients without coronary artery disease had normal exercise images (specificity 97 percent). Thallium-201 imaging predicted the correct diagnosis in 56 patients (86 percent). Thus, exercise myocardial imaging with thallium-201 appears to be a useful diagnostic aid in patients with an inconclusive exercise electrocardiogram.

The noninvasive assessment of anomalous origin of the left coronary artery from the pulmonary artery.

We present a patient with anomalous origin of the left main coronary artery from the pulmonary artery. We correlate the findings of echocardiography and myocardial imaging with angiography, and discuss the value of the noninvasive techniques in the diagnosis and in the followup of such patients.