[Comparative study of vasa vasorum and neointima in conduits for coronary artery bypass grafting]. / Sravnitel'noe izuchenie vasa vasorum i neointimy v konduitakh dlia koronarnogo shuntirovaniia.

AIM: This study was undertaken to investigate the preoperative incidence and severity of intimal hypertrophy, as well as the level of blood supply of arterial and venous conduits for coronary artery bypass grafting. MATERIAL AND METHODS: Segments of the internal thoracic artery and great saphenous vein (n=13) were harvested pairwise during coronary artery bypass grafting and were then visualized by scanning electron microscopy in back-scattered electrons. The analysis of the incidence and thickness of intimal hypertrophy, as well as the calculation of the number and the area of the vasa vasorum were performed using the programme ImageJ. RESULTS: Intimal hypertrophy was more characteristic for the great saphenous vein as compared with the internal thoracic artery (9/13 (69.2%) and 7/13 (55.8%), respectively), although this difference did not reach statistical significance. The maximal-to-minimal neointimal thickness ratio correlated with the percentage of stenosis (r=0.875, p<0.0001), the area (r=0.45, p=0.023) and the number (r=0.47, p=0.015) of the vasa vasorum in the conduits, thus confirming the hypothesis on possible participation of these vessels in the development of intimal hypertrophy, with the area of the vasa vasorum being greater in the vessels with >10% stenosis (p=0.051). The number of the vasa vasorum in the great saphenous vein exceeded that in the internal thoracic artery (p=0.0005), with this difference remaining significant after adjustment for the area of the adventitia (p=0.027). The number of the vasa vasorum per the percentage of stenosis in the great saphenous vein also exceeded that in the internal thoracic artery (p=0.039) and more strongly correlated with intimal hypertrophy in the great saphenous vein as compared with that in the internal thoracic artery (r=0.53 and r=0.27, respectively). CONCLUSION: Intimal hypertrophy correlates with the area and number of the vasa vasorum in conduits. The great saphenous vein is characterised by a larger number and higher density of the vasa vasorum as compared with the internal thoracic artery. The number of the vasa vasorum is correlated with stenosis of the great saphenous vein more closely than with stenosis of the internal thoracic artery. This may be suggestive of significant predisposition of the great saphenous vein to the onset of adventitial inflammation followed by the development of intimal hypertrophy.

[Renal calculus microflora in urolithiasis and search for agents of control of biofilms formed by uropathogenic bacteria].

AIM: Study bacterial biofilms in native material (renal calculus) by electron microscopy method and developmeit of biofilm model by isolates in vitro on sterile calculi of various chemical composition. MATERIALS AND METHODS: Bacterial spectra of microflora of renal calculus lavages were studied, isolated pure cultures were identified up to species. Comparisons of urine microflora obtained before operation in patients with urolithiasis with microflora of removed renal calculi were carried out. RESULTS: Urease activity and genes coding pathogenicity factors were detected, and the ability to form biofilms by isolates was studied. Model of formation of biofilms in vitro on sterile renal calculi was developed and candidate agents reducing the biofilm forming ability were tested. CONCLUSION: Uropathogenic microorganisms infecting renal calculi and forming biofilms on them not only support chronic infection by increased resistance to therapy but also facilitate novel lithogenesis.

[The gene encoding the outer membrane lipoprotein lipL32 as a genetic target for developing leptospira genotyping schemes].

The primers flanking the fragments sized 677 bp (external) and 204 (internal) were constructed on the basis of nucleotide sequences of the gene encoding the outer membrane lipoprotein LipL32. PCR-analysis was used to study the prevalence of the gene lipL32 among 79 Leptospiraceae family strains representing different genera and genomic species (77--genus Leptospira, 1--genus Leptonema, 1--genus Turneria). The two amplicons were detected in the pathogenic leptospires--L. interrogans (except L. inadai), but not in saprophytic--L. biflexa. In L. inadai only 204 bp-amplicon was detected. These test-systems can be successfully used to differentiate between two distinct ecological groups of leptospires. The gene encoding the lipL32 seems to be appropriate as an adequate genetic target for developing the leptospira genotyping systems (high prevalence, presence of both conservative and variable sites in its nucleotide schemes).

[Identification of genes controlling the transition of Salmonella typhimurium bacteria to a non-culturable state]. / Identifikatsiia genov, kontroliruiushchikh perekhod bakterii Salmonella typhimurium v nekul'tiviruemoe sostoianie.

Mutants of Salmonella typhimurium with an impaired process of transition to the nonculturable state were tainted. Mutants were divided into four phenotypic groups. In four mutants (representatives of each phenotypic group), genes with TnPhoA transposon insertions were cloned; these insertions caused a disturbance in the process of mutant cell transition to the nonculturable state. Nucleotide sequences of mutant gene fragments were determined. Comparison of nucleotide sequences obtained with a data bank on DNA nucleotide sequences of enterobacterial genomes allowed the identification of four genes involved in the control of nonculturable form generation in salmonellae.

[Isolation and characteristics of Salmonella typhimurium mutants with a disrupted process of generating nonculturable forms]. / Vydelenie i kharakteristika mutantov Salmonella typhimurium s narushennym protsessom obrazovaniia nekul'tiviruemykh form.

A laboratory model of the induction of nonculturable forms in Salmonella typhimurium has been developed. Mutants of S. typhimurium were obtained using insertion mutagenesis via the TnPhoA transposon. These mutants were impaired in the cell transition from the vegetative to the nonculturable state assayed in this model. Mutants have various phenotypes and are located in different regions of the chromosome, as shown by the data obtained using pulsed-field electrophoresis of genomic DNA.

[The resistance plasmid of Klebsiella pneumoniae that controls its cytotoxic activity]. / Plazmida rezistentnosti Klebsiella pneumoniae, kontroliruiushchaia tsitotoksicheskuiu aktivnost'.

R-plasmid (40 MD) isolated from K. pneumoniae hospital strain makes Escherichia coli strain J62 capable of inducing a cytotoxic effect which can be detected in Hep-2 cell culture. In contrast to the initial E. coli strain J62 producing no changes in the monolayer, E. coli J62 cells containing P-plasmid induced pronounced cytotoxic changes and a sharp increase in the number of nonviable Hep-2 cells by hour 24 of interaction.

[A new site-specific endodeoxyribonuclease EcoHI]. / Novaia saitspetsificheskaia éndodezoksiribonukleaza EcoHI.

A new sitespecific endonuclease of the II class EcoHI has been isolated from Escherichia coli strain and characterized. Restriction endonuclease EcoHI recognises the nucleotide sequence C C (C/G) G G with the cleavage site between the fourth and fifth nucleotide. It is an isoshizomer of the restriction endonuclease CauII. The yield of enzyme is 2500 units of activity per 1 g of biomass. The producing strain Escherichia coli HI is nonpathogenic, easily grown with the antibiotic resistance markers permitting to cultivate the strain under selective conditions.

[Isolation and primary characteristics of elastase from a clinical strain of Pseudomonas aeruginosa]. / Poluchenie i pervichnaia kharakteristika élastazy iz klinicheskogo shtamma Pseudomonas aeruginosa.

The homogeneous preparation of elastase has been obtained from P. aeruginosa clinical strain. The molecular weight of the isolated enzyme is 33,000 daltons, and its isoelectric point is 6.8. Two media manufactured in this country (dialyzed bovine heart hydrolysate and a dried semisynthetic medium) ensuring good production of the enzyme have been proposed. The optimum time for the cultivation of the producer strain (30-40 hours) has been established. Elastase has been shown to be widely spread among P. aeruginosa clinical strains.

[Physico-chemical and biological characteristics of Pseudomonas aeruginosa elastase]. / Nekotorye fiziko-khimicheskie i biologicheskie kharakteristiki élastazy Pseudomonas aeruginosa.

Elastase isolated from P. aeruginosa clinical strain hydrolyzes elastin, casein, hemoglobin, ovalbumin, gelatin, fibrin, collagen. The optimum pH ensuring the activity of the enzyme is 7.8-8.0. Elastase shows maximum stability at pH 6.6-9.0. Heating at 80 degrees C for 10 minutes results in its practically complete inactivation. Elastase is a highly radiosensitive enzyme. Chelating agents and zinc, cobalt, mercury ions suppress its activity. Sodium and ammonium chlorides selectively inhibit the elastolytic, but not proteolytic activity of the enzyme. Elastase shows pronounced dermonecrotic and keratolytic action.

[Possible use of plasmids for studying the effect of space flight factors on biological objects]. / Vozmozhnost' ispol'zovaniia plazmid dlia izucheniia vliianiia faktorov kosmicheskogo poleta na biologicheskie ob"ekty.

The action of space flight factors on the phenotype and certain molecular and genetic parameters of E. coli plasmids (R, Col, Hly and others) was studied. The E. coli strains were grown and multiplied in the "Cytos" apparatus during the orbital flight of "Salyut-7" in June 1982. A synchronous experiment in the "Cytos" apparatus was performed under the Earth conditions. It was shown that space flight factors had no effect on the properties of the test strains and plasmids (antibiotic resistance, capacity for production of colicin, hemolysin, restriction endonuclease, conjugative capacity, frequency of conjugative transfers and molecular weight).

[Properties of Serratia marcescens strains isolated in septic diseases of newborn infants]. / Svoistva shtammov Serratia marcescens, vydelennykh pri septicheskikh zabolevaniiakh novorozhdennykh.

As the result of the study of blood and liquor samples from 120 newborns, Serratia marcescens was isolated in 21 cases (17.5 %). 8 strains were isolated from the environment of these patients. Almost all strains isolated from both the patients and the environment (with the exception of one environmental strain) belonged to serotype 04. The isolated S. marcescens strains were resistant to penicillin, ampicillin, streptomycin, kanamycin, oxacillin, methicillin, ceporin and moderately sensitive to polymixin. 2 strains from the environment and 9 strains from the patients were mildly sensitive to gentamicin. In one hospital all isolated strains were found to have 2 transmissive R plasmids with the molecular weight 40 and 60 megadaltons. The presence of R plasmids with the same molecular weight in all S. marcescens strains isolated in this hospital, as well as their serological identity, suggest that in all patients infection originated from a common source.

[Effect of R plasmids on the growth characteristics of Shigella sonnei and Escherichia coli]. / Izuchenie vliianiia R-plazmid na rostovye kharakteristiki Shigella sonnei i Escherichia coli.

Revealing of growth characteristics in plasmid and plasmid-free strains was studied with the use of two different hosts: E. coli 15-3 and Sh. sonnei 11-941 containing conjugative R plasmids differing in the set of the resistance markers. It was shown that the R plasmids had no noticeable effect on the period of the lag phase and the time of the microbial cell generation. It was also shown that the number of the viable cells in separate cultures of the plasmid-free strain of Sh. sonnei 11-941 and its plasmid variants was of the same order. Counting of the viable cells in mixed cultures of the plasmid-free strain of E. coli 15-3 and its plasmid variant on the complete nutrient medium revealed an insignificant increase (by 10 per cent) in the proportion of the bacteria carrying the plasmid after 6-hour growth (during early stationary growth phase) and later, up to 24 hours. The results of the study suggested that development of nutrient media for microbial strains containing R plasmids does not require additional cultivation conditions.

[Use of genetic and molecular characteristics of R plasmids as an epidemiological marker in an outbreak of hospital infection]. / Ispol'zovanie geneticheskoi i molekuliarnoi l kharakteristiki R-plazmid v kachestve épidemiologicheskogo markera pri vspyshke vnutribol'nichnoi infektsii.

Antibiotic sensitivity of 38 strains of enteric bacteria, such as Serratia marcescens Klebsiella pneumoniae and others and Ps. aeruginosa isolated during an outbreak of meningitis in a premature infant resuscitation department was studied. It was shown that all the isolates were multiple resistant, most frequently to 7 antibiotics. All the resistance markers were transferred on conjugation, segregation of some markers being observed. Investigation of the plasmid composition of the clinical strains and transconjugants of E. coli revaled the presence of 2 plasmids with the molecular weights of 40 and 60 Md or one of them. The restriction analysis demonstrated that the plasmids with the same molecular weights isolated from different strains were identical. It was suggested that such plasmids originated from the same source and were distributed by conjugation. The possible part of R plasmids in epidemiological analysis of hospital infections is discussed: the possible part as an additional marker in determination of the infection source and the possible part through its ability to change the host cell phenotype, including the phage and bacteriocin types.

[Possible dependence of the results of phage typing Ps. aeruginosa strains on the presence of R plasmids]. / Vozmozhnaia zavisimost' rezul'tatov fagotipirovaniia shtammov Ps. aeruginosa ot nalichiia R-plazmid.

The plasmid composition of 209 strains of Ps. aeruginosa was determined. The strains were isolated from patients, animals and environment in different geographical areas. The number of the plasmid-containing strains averaged 26.8 per cent. The molecular weights of the plasmids varied from less than 10 to more than 150 MD. 41 conjugative plasmids were transmitted to the recipients of Ps. aeruginosa RAO 303. 66 per cent of them had a restrictive effect on the development of phages used in genetic studies, epidemiological phage typing (Lindberg Collection), and medical practice. This resulted in the changing of the phage type of the host strain. Similar results were obtained in the studies with 10 standard R plasmids representing different incompatibility groups. No relation between the spectrum of the phage restriction, group specificity and the other properties of the plasmids was observed. About 50 per cent of the plasmids markedly lowered the sensitivity level of Ps. aeruginosa RAO 303 to the therapeutic pyocyanic phage. The systems of restriction and modification of DNA coded with plasmids were not detected. A possible changing of the phage type of Ps. aeruginosa strains under the effect of R plasmids should be considered in epidemiological assays and respective treatment measures.

[Resistance to nalidixic acid in tetracycline-resistant mutants of E. coli]. / Ustoichivost' k nalidiksovoi kislote tetratsiklinrezistentnykh mutantov E

The studies on the effect of nalidixic acid (negram) on the synthesis of DNA and determination of its minimal inhibitory concentrations revealed a regular decrease in the sensitivity levels to negram of the tetracycline resistant mutants selected on media with tetracycline. Heterogene ty of the tetracycline resistant mutants to EDTA showed that one of the causes of insensitivity of the mutants to negram was a change in the surface structures of the microbial cell.