Morbidity: terminology, mechanisms of formation and classification

In the 70-ies of the last century the evolution of the epidemic process doctrine resulted in developing population approach to morbidity analysis, in addition to the traditional focal approach. On the one hand, this led to the discussion on the possibility of applying such notion to non-infectious diseases and, on the other hand, to the discussion on the mechanisms of the development and formation of different manifestations in infectious diseases. In both cases the discussion was centered on the phenomenon of morbidity. The present article deals with the nature of morbidity as a phenomenon and the acceptability of general scientific approaches in the interpretation of seasonal and cyclic character of morbidity from the viewpoint of the wave process in an open system. On the basis of the data presented in this work the terms used in epidemiology in considering manifestations of the epidemic process are discussed. The improved classification of morbidity by qualitative and quantitative signs for infectious diseases is proposed.     

Evaluation of amyxin effect in prophylaxis of acute respiratory viral infections

The results of the evaluation of the oral inductor of endogenic interferon (amyxin), manufactured in Russia are presented. The use of amyxin was found to produce a drop in morbidity in acute respiratory virus infections (ARVI) among medical workers 3.4 times, i.e. the preparation exhibited a pronounced prophylactic effect with respect to ARVI. The use of the preparation was accompanied by a decrease in the number of manifest forms of ARVI. Persons given the preparation often had ARVI in a mild or asymptomatic form.     

Structural changes of the nucleolar organizing regions in rhabdomyosarcoma RA-23 tumor cells induced by okadaic acid

It has been recently shown that okadaic acid (OA), an inhibitor of dephosphorilation, is capable of inducing changes in the nucleolar organizer regions (AgNORs) of some mammalian cells. Our work was focused on studying the structural changes in AgNORs of tumour cells of rat rhabdomyosarcoma RA-23 by their exposure to 100 nM OA. A standard silver staining procedure of interphase AgNORs in tumour cells was used. We measured no less than 100 tumour cells in each clone. In the examined tumour cell populations, the index of interphase AgNORs varied from 1.54 to 4.35. A clear structure and form of AgNORs was not observed in 30% okadaic acid-treated tumour cells, as opposed to 10% of the control ones. AgNORs in these cells looked like a mixture of thin threads encompassing some dark dots lying, mostly, separately. Additional procedures of tumour cell staining with Giemsa and fluorescent dye Hoechst 33,258, respectively, revealed that such structures were not chromosomes. Meanwhile, the frequency of cells at the stage of prophase exceeded 3%, as opposed to the control, where the frequency of cells at this stage was less than 0.5%. Thus, we can conclude that we have detected specific changes in AgNORs and chromatin structure of okadaic acid-treated tumour cells.     

Electroconvulsive shock causes neuronal death in the mouse hippocampus: correlation of neurodegeneration and convulsive activity

Relations between seizures induced by repeated electroshock (ES) and structural changes in the hippocampus were investigated in Balb/C mice. Brain sections of the animals 2 or 7 days after the last ES were stained for Nissl or TUNEL (apoptotic nuclei). Direct measurement of caspase-3 activity (a key enzyme of apoptosis) in brain regions was performed immediately after the last ES. Statistically significant, albeit moderate cell loss was demonstrated in the CA1 field and dentate gyrus, but not in the CA3 field of the hippocampus. The number of neurons in these fields inversely correlated with seizure severity. No apoptotic nuclei could be revealed either in hippocampus or in other brain regions. Caspase-3 in the hippocampus decreased after ES. The data obtained support the results from other groups showing prominent functional changes in neurons induced by repeated ES and extend this concept directly testifying for a moderate (within 10%), albeit statistically significant neuronal death in selected hippocampal fields. The inverse correlation of cell number with severity of seizures suggest that these are seizures inducing neuronal death.     

RAPD fingerprinting of common bream Abramis brama L., roach Rutilus rutilus L., and their F1 hybrids

The polymerase chain reaction with arbitrary primers (RAPD-PCR) was used to study and to evaluate the genetic variation in the hybrid progeny of two Cyprinidae species, common bream Abramis brama and roach Rutilus rutilus. Genetic polymorphism was studied in 20 fishes (young of the current year) obtained in four individual crosses: R. rutilus x R. rutilus (RR), A. brama x A. brama (AA), R. rutilus x A. brama (RA), and A. brama x R. rutilus (AR). Amplification spectra obtained with eight primers contained 288 fragments, 97.6% of which proved to be polymorphic. The proportion of polymorphic fragments was 75.0% in the RR progeny, 58.1% in the AA progeny, 84.9% in the AR progeny, and 77.8% in the RA progeny. Classification analysis in the space of principal components was performed with the first four components, which together accounted for 64% of the total variance of the character under study. The individual contributions of components I, II, III, and IV were 26.8, 16.8, 11.5, and 8.9%, respectively. Fishes of the two pure species and the hybrid progeny (direct and reverse hybrids together) were clearly differentiated in the space of principal components I and II. The best differentiation of the four samples (RR, AA, RA, and AR) was observed in the space of principal components II and IV. Possible causes of high genetic variation in interspecific hybrids are discussed.     

Persistent properties of Brucella abortus isolated from various sources

Persistence factors in 70 B. abortus strains isolated from different sources were studied. Depending on the source of the isolation of B. abortus, the spread of their antilysozyme, anticomplementary, antiintercidal activity was determined and intraspecific differences in the manifestation of these signs were established. The highest spread and manifestation of persistence factors was registered in B. abortus populations isolated from brucellosis patients and from cattle.     

The treatment of isolated genera

Problems presented by genera, or small groups of genera, which have been given family rank are reviewed, and the genera are divided into a number of categories according to the closeness of their affinity to other genera or families. Satellite genera that stand in close relation to families should be united with them. Binary families, that have been divided into two (or more) related families, should be re–united. Families connected by linking genera, should, logically, be united but practical considerations usually prevent this. Clusters of diverse but more or less distantly related genera present unusual problems, being treated either as several, often monogeneric families or as a loosely structured family. Truly isolated genera must be given family and often ordinal rank.     

Improved method of lipopolysaccharide isolation from gram-negative bacteria

A modification of the traditional method for lipoplysaccharide isolation from the cells of grammnegative bacteria was elaborated on the basis of extraction by the hot water solution of phenol (the method of Westfahl). To make the method simpler and to raise the yield of the product it was proposed to use the water-phenol extract without its division for plases. The nucleic acids are eliminated by precipitation from dialyzed extract at pH 3,2-3,4 achieved by addition of acetic acid. The comparative isolation of lipopolysaccharides by the classic and modified methods has confirmed the advantages of a new technique.     

Analysis of the survival rate in a combined radiation lesion. The evaluation of synergism (or antagonism) in the case of 2 exposures

The method of the estimation of interaction between two harmful effects based on the statistical survival rate data is discussed. In terms of the competitive risk model, an independent effect was defined as a product of survival functions corresponding to an isolated effect of each injurious factor. The proposed method is based on the comparison between the animals' lifetimes in the case of the isolated effects and the actual survival rates after the combined radiation effect. The comparison of the two alternatives was made by the regression model of Cox adapted for the purposes of this study.