Locomotor-like movements evoked by leg muscle vibration in humans

We attempted to elicit automatic stepping in healthy humans using appropriate afferent stimulation. It was found that continuous leg muscle vibration produced rhythmic locomotor-like stepping movements of the suspended leg, persisting up to the end of stimulation and sometimes outlasting it by a few cycles. Air-stepping elicited by vibration did not differ from the intentional stepping under the same conditions, and involved movements in hip and knee joints with reciprocal electromyogram (EMG) bursts in corresponding flexor and extensor muscles. The phase shift between evoked hip and knee movements could be positive or negative, corresponding to 'backward' or 'forward' locomotion. Such an essential feature of natural human locomotion as alternating movements of two legs, was also present in vibratory-evoked leg movements under appropriate conditions. It is suggested that vibration evokes locomotor-like movements because vibratory-induced afferent input sets into active state the central structures responsible for stepping generation.     

Morphohistological aspects of tumors and tumor-like changes in the thyroid gland

The results of the thyroid gland (TG) state investigation in 1027 patients, ageing from 14 to 75 years, operated on in 1986-1995 yrs., are adduced. In 60.5% of patients the diffuse-nodular goitre was diagnosed, in 9.5%--Hashimoto's thyroiditis, in 9.5%--TG cancer, in 2.8%--other pathology. To establish the interrelationship of pre-cancer changes and a TG cancer it is necessary to point out the concomitant morphologic change beside the main diagnosis, which determines the clinical tactics.     

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.