Potentiometric and spectrophotometric determination of the dissociation constants of mesatone and epinephrine

The dissociation constants of proton-acceptor and-donor groups of adrenaline (epinephrine) and mesatone were determined by potentiometric and spectrophotometric titration method. The potentiometric titration data were used to calculate the protonation constants of a secondary amino group in each drug, and the spectrophotometric titration data were used to determine the dissociation constants of OH groups influencing the distribution of electron density in the chromophore (aromatic system). Once the dissociation constants are known, the distributions of the ionized forms of epinephrine and mesatone at various H can be calculated. In these calculations, it is important to take into consideration the transport of biologically active molecules through membranes and their interactions with receptors. __________ Translated from Khimiko-Farmatsevticheskii Zhurnal, Vol. 39, No. 12, pp. 47–50, December, 2005.     

Myoglobin immunoassay based on metal particle-enhanced fluorescence

Enhanced fluorescence on silver island films (SIFs) is utilized to develop a sandwich-format immunoassay for the cardiac marker myoglobin (Myo). Myoglobin was first captured on surfaces coated with anti-Myo antibodies; the surface was then incubated with fluorescently labeled anti-Myo antibodies. The system was examined on glass surfaces and on SIFs. We observed the enhancement of the signal from SIFs in the range of 10-15-fold if compared to the signal from the glass substrate not modified with a SIF. A kinetic immunoassay for Myo on SIF-modified surface results in a decreased background signal. The initial results show that it is possible to detect Myoglobin concentrations below 50 ng/mL, which is lower than clinical cut-off for Myoglobin in healthy patients. We suggest the use of SIF-modified substrates for increasing the sensitivity of surface assays with fluorescence detection.     

Planning of orthodontic treatment in patients with maxillary dentition defects using mathematical methods

Stress-deformed status of bone tissue in the implantation zone was studied. The relationship between the level of strain in the spongy and cortical layers of the bone and spatial location of the implant in the jaw and its geometrical parameters is demonstrated. Numerical analysis of the level of bone tissue stress was carried out on the basis of experimentally created three-dimensional solid-body model of the maxilla. The process of changes in the distribution of tensions during different phases of mastication was investigated. The potentialities of numerical analysis in the planning of orthodontic treatment of patients with dentition defects making use of implants are demonstrated.     

Prostaglandin E2 Release by Human and Syrian Hamster Tumor Cells and Their Sensitivity to Cytostatic Activity of Natural Killers

The release of prostaglandin E₂ by human and Syrian hamster tumor cells in response to contact with natural killers and their sensitivity to cytostatic activity of natural killers were studied. A previously reported correlation between prostaglandin E₂ release by Syrian hamster tumor cells and their resistance to cytostatic activity of natural killers was confirmed. This resistance can be cancelled by inhibition of prostaglandin E₂ release with indomethacin. Unlike malignant tumor cells of Syrian hamsters, only few human tumor cells resistant to cytostatic activity of natural killers secrete prostaglandin E₂. The resistance of these cell strains to cytostatic activity of natural killers could be cancelled by indomethacin treatment. Possible role of prostaglandin E₂ release as a mechanism of tumor cell protection from effector cells of this type of natural (congenital) immunity is discussed.     

Formation of population groups with a higher risk of tuberculosis

During the years when tuberculosis was diagnosed among all age, sex, social and occupational groups of the population, methodological approaches to the organization of antituberculosis care based on annual antituberculosis preventive activities and covering practically all populations were the only proper measures bringing about their own positive results. Nowadays the annual preventive activities should be launched in those population groups where cases of tuberculosis are detected most frequently. To classify risk factors directly responsible for tuberculosis endemia, questionnaires were sent to 477 newly diagnosed adult patients. The obtained data were computer processed. Unfavourable social and biomedical factors, including alcoholism, unsatisfactory economic, working and living conditions, contact with tuberculosis patients, concurrent diseases and other social factors, have a decisive effect on the tuberculosis morbidity.