The transformation of acute viral hepatitis B into chronic

500 patients with hepatitis B have been followed up from the acute onset to long-term outcome. As for chronic transformation of the disease, at higher risk are patients with mild form, progredient run and inadequate immune response. Of the highest value for identification and prognostication was a dynamic quantitative control over the system HBeAg-anti-HBe providing separate prognosis of establishment of replicative or integrative variants of chronic hepatitis B. In progredient infection an early administration of reaferon in combination with thymogen is thought valid which in many patients is sufficient to prevent the disease transformation into a chronic form.     

Role of oxygen extraction from coronary blood in the regulation of oxygen transport to the myocardium

Experiments on anesthetized dogs were made to examine oxygen extraction from coronary blood during increase and decrease in cardiac rhythm frequency under varying conditions of vasomotor regulation. With an initially high tone of the coronary vessels both increase and reduction of myocardial oxygen supply occurred at the expense of vasomotor reactions. Under these conditions the coronary blood flow velocity and systolic rhythm correlated well. At the same time the oxygen level in coronary blood did not experience noticeable changes. As the initial tone of the coronary vessels dropped, vasomotor reactions were attenuated and oxygen extraction from coronary blood underwent alterations which had occurred prior to depletion of the coronary expanding reserves. The data obtained suggest that reduction of the initial tone of the coronary vessels proceeds non-uniformly, leading to a decrease in vascular sensitivity to the tissue oxygen level.     

Amino acid contribution to the genetic code structure: end-atom chemical rules of doublet composition

Up-to-date knowledge is not yet enough to prove or reject completely one of the leading alternative hypotheses considering external or internal origin of the genetic code organization (term "internal" means a peculiarity of amino acids and nucleotides which can propose some logical basis for explanation why definite codons are assigned to particular and not to other amino acids; term "external" in this context implies tRNAs and aminoacyl-tRNA synthetases which provide accuracy of translation but are not presented in the code table in the evident from). New data in favour of the internal approach have been proposed. A close correlation exists between chemical nature of single, the most remote from C alpha, end atoms of amino acid side chains and types of bases in appropriate codon doublets. There are two main rules reflecting this correspondence: (1) all O- or N-ended amino acids (i.e. with O, OO, N, NN, ON, OC and NC end patterns) possess the A-containing codon doublets; (2) all solely C-ended (excluding Ala) and S-ended amino acids (i.e. residues with C, CC and S ends) have the U-containing codon doublets. The discovered asymmetry is characterized by the following high reliable differences of A and U distribution among 21 patterns of individual doublets belonging to 18 amino acids (Pro and Gly are discarded): (a) proportion of A plus U bases corresponding to the two rules, 22/26 is much more than proportion of such bases in violating cases, 4/26; (b) A and U are dominant bases over each of other base types in the doublets of O/N- and C/S-ending amino acids, respectively; (c) the numbers of doublets bearing (18) and not bearing (3) dominant A or U bases are also significantly different. The concept of indicative amino acid end atoms (O/N and non-O/non-N) and doublet A/U bases has been proposed and discussed as so far unknown regulative system of submolecular level of heredity which, additionally to possible key role in the process of the genetic code arising, provides now control of its universality, stability and fidelity.     

Thymomas with a myasthenic syndrome

2560 patients with generalized myasthenia (Gm) were operated during 1960-1996. Tumors of the thymus (TT) which are the most often neoplastic masses of anterior mediastinum were revealed in 312 patients. Among them organ-specific tumors (thymomas, cancers) were detected in 252 patients (95.8%). Comparative analysis of effectiveness of a number of special methods of diagnostics of TT showed that CT and magnetic resonance tomography are the most sensitive and specific methods. Thymoma-thymectomy was carried out in 247 patients, among them in 93 (37.7%)--extended one. Postoperative lethality made up 5.1%, last years (1990-1996) there were no fatal outcomes. Among early postoperative complications wound infection was observed in 2.5% of patients, pneumonia--in 1.3%, myasthenic crisis--in 1.6%. Basing on histogenetic classification, following kinds of thymomas were singled out: in 58.9% cortical ("light cellular"), in 2.2%--medullar ("dark cellular") and in 38.9%--mixed cellular thymomas. Long-term results of thymectomy in patients with Gm in various kinds of thymomas were different: at the 5th year of follow-up they are worse in cortical cellular types and much better in medullar--cellular and mixed cellular thymomas with prevalence of medullar component.     

Modification of cytochrome P-450 apoenzyme during its oxidative self-inactivation in a reconstituted mono-oxygenase system

Determination of the doubling time for a population of cells can involve tedious calculations. We have developed computer software for MS-DOS microcomputers to expedite the analysis of tumor cell growth in vitro and in vivo. This program, DOUBLE-TIME, assists in the collection of cell numbers into a database and calculates the doubling time for a population of cells from the plot of cell growth over time. For experiments where tumor mass is measured in vivo, the software collects measurements of tumor size, calculates tumor volume (mass), generates growth curves for tumor volume change over time, and determines the doubling time of the tumor and the mean for multiple tumors. DOUBLE-TIME plots both total and viable cell numbers over time, calculates standard error of the doubling time, and the doubling time for a selected portion of a growth curve. This software also automates the cell counting process with a software-generated cell counter that allows cell counts to be tallied directly into the computer via a mouse.     

Role of DNA definite structural elements in interaction with repair enzyme uracil-DNA glycosylase

Interaction of different oligodeoxyribonucleotides (oligos), their analogs and oligonucleopeptide with uracil-DNA glycosylase (UDG) from human placenta was investigated. It is shown that there is no considerable contribution of heterocyclic bases of DNA to UDG-substrate binding but the UDG interaction with some DNA phosphate groups is necessary for enzyme-substrate recognition. However the phosphate group adjacent to single dU from the 3'-end in oligo is not involved into the electrostatic contact with UDG. It is found that UDG has the high affinity to its reaction product. An oligonucleotide containing a single 2'-deoxy-2'-aminouridine is a non-hydrolyzable substrate analog for UDG.