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Biomedical subjects

V D Kuznetsov

Publications and source records attributed to V D Kuznetsov.

At least 19 recordsLinked to original sources
PubMed1992

Intrapopulation variability of antibiotic biosynthesis in streptomycetes.

Spontaneous variants making up parallel series of hereditary variability inside the populations of antibiotic-producing actinomycetes differ in the level of their antibiotic activity. As a rule, spontaneous variants of the basic type possess the highest antibiotic activity. Other variants representing parallel series have a lower activity level. This raises the possibility to carry out a directed selection of previously known active colonies from populations on the basis of their easily discernible morphological properties. It enhances the efficiency of selection work both in the case of stabilization of the level of antibiotic activity and in the case of obtaining more productive commercial strains.

Anti-Bacterial Agents↗
PubMed1991

[Immunological study of lysates from the cell wall of group A Streptococcus].

The chemical composition and presence of immunogenic components in the lysates of the cell walls of group A Streptococcus, type M29, were studied. The lysates were prepared with the use of muramidase. Fc-Receptors were detected in the lysates. Within the first 30 minutes of cell wall lysis by muramidase, 4 times higher amounts of the protein reacting with fibrinogen excreted than in the subsequent 4 hours. The lysates contained immunogenic proteins. Fraction III isolated by chromatography of the 30-minute lysate on DEAE-trisacryl formed a single precipitation band with lysate antiserum. The lysate Fraction IV forming three precipitation bands contained a protein not specific of the type. The protein was identical to the protein antigen from Triton X-100 extracts of group A Streptococcus, types M1, M12 and M29. The group-specific polysaccharide was detected in the lysate Fraction I and Fraction II of the 4-hour lysate.

Bacterial Proteins↗
PubMed1991

[Erroneous laparotomy in emergency surgery].

The authors studied the data concerning 101 patients who had undergone erroneous laparotomy for suspected acute surgical disease; these accounted for 0.4% of all the patients who were operated on for emergency indications in the same period. Eleven patients died. The operation was undertaken for an erroneous diagnosis of acute appendicitis (32 patients), acute cholecystitis (18), perforating gastric ulcer (15), peritonitis of unknown etiology (14), acute intestinal obstruction (5), strangulated hernia (3), destructive pancreatitis (3), tumor of the large intestine complicated by obstruction (3), abdominal abscess (2), thrombosis of the mesenteric vessels (1), ovarian apoplexy (1), closed abdominal trauma with injury to the viscera (4 patients). Diseases simulating the clinical picture of "acute abdomen" but not requiring an emergency operation were as follows: female reproductive (20 patients), pancreatic (11), renal diseases (11), hepatitis, cirrhosis of the liver (10), cardiovascular (9), pulmonary diseases (5), mesoadenitis (5), Crohn's disease (3), chronic colitis (3), carcinomatosis of the peritoneum (3), herpes zoster (3), and other diseases and injuries (20 patients). The main causes of the diagnostic and tactical errors were objective difficulties in the differential diagnosis due to similar symptomatology, as well as errors in the examination of the patient and haste in making a decision to make an operation.

Abdomen, Acute↗
PubMed1991

[Treatment of peptic ulcer hemorrhages].

The article analyses experience in treatment of 297 patients with gastroduodenal bleeding of ulcerous etiology. Operative interventions after arrest of bleeding and the appropriate preoperative management produce better results (the mortality rate, 3.3%) than those of emergency operations (the mortality rate, 15.7%). It is therefore advisable to start treatment of patients with gastroduodenal bleeding by means of nonoperative measures which proved effective in 61.6% of cases. In doubtful reliability of hemostasis, patients with moderate and severe bleeding should be operated on in the immediate days after hospitalization without waiting for a possible recurrent bleeding. Gastric resection is the main type of operative intervention in bleeding from a gastric ulcer. In a bleeding duodenal ulcer both resection of the stomach and economical operations--vagotomy, excision or closure of the ulcer, pyloroplasty--are equally competent.

Adolescent↗
PubMed1990

[Repeated operations in gastric and duodenal ulcers].

The results of repeated operations in 165 patients were studied. A second operative intervention was indicated most frequently after closure of a perforating ulcer (h = 126). The character of the second operative intervention was determined by the method of the previous operation and the complication of the ulcer for which the operation had to be repeated, the patient's condition and age, and the urgency of the surgery. The mortality rate after repeated operative interventions was 3%.

Duodenal Ulcer↗
PubMed1989

[The diagnosis and surgical procedure in perforated gastroduodenal ulcer].

An analysis of results of treatment of 476 patients with perforating gastroduodenal ulcers has shown that choice of the operative method must be differentiated with special reference to the patient's age, localization of ulcer and its morphological characteristics, time from perforation till operation, general state of the patient and availability of conditions for a certain operation.

Adult↗
PubMed1989

[Study of the composition of cell wall of group A Streptococcus after hydrolysis using muramidase from Streptomyces levoris].

The aim of the experiment was to study the lysis products of cell walls of group A streptococci resulting from exposure to N-acetylmuramidase. It was shown that for isolating surface proteins free of polysaccharide and peptidoglycan fragments it was necessary to treat the streptococcal cell walls with endo-beta-N-acetylmuramidase for no more than 30 minutes. Prolonged hydrolysis with muramidase led to the presence of polysaccharide and the peptidoglycan fragments in the protein fractions, intracellular wall proteins covalently bound to the peptidoglycan fragments and polysaccharide being also released.

Bacterial Proteins↗
PubMed1988

[Isolation and various properties of the lytic enzyme preparation from Streptomyces griseus].

Certain optimal parameters were determined for production of a pure enzyme preparation of the GIOx type from S. griseus by precipitating the enzymes from concentrated fermentation broth filtrate. Antibacterial spectrum of the preparation is comparatively narrow. Still, it showed high lytic activity against streptococci and staphylococci. Investigation of the preparation with the electrofocusing technique revealed that the main lysing component was a protein fraction with its isoelectric point within 8-10.5.

Acetone↗
PubMed1988

[Risk factors in surgical treatment of acute cholecystitis].

Results of the operative treatment of 1574 patients with acute cholecystitis are analyzed. Main factors responsible for the development of unfavourable results of operation are late operations on patients with the developed pyo-septic complications of cholecystitis, senility and severe concomitant diseases as well as some medical errors.

Acute Disease↗
PubMed1985

[Experience with long-term preservation of international-standard cultures of Actinomycetes].

The results of the study on long-term maintenance (1-12 years) of 453 reference cultures of actinomycetes are presented. The cultures were maintained with the following methods: lyophilization, soil cultures and periodical passages on agarized nutrient media. Lyophilization was most efficient for storage of the majority of the cultures: 346 strains (77.4 per cent) preserved high viability over the observation period of 11-12 years. Lyophilization appeared less favourable for the cultures with low sporulation. The efficacy of the method of soil cultures on long-term storage of the whorl actinomycetes was low: 88 per cent of Streptoverticillium lost their viability within 1-2 years. However, this method was valuable for stabilization of the taxonomic features of streptomycetes. The maintenance of the actinomycetes by regular passages on agarized media every 6 months resulted in the changing of the cultural and morphological features in a number of the strains.

Actinomycetales↗
PubMed1985

[Spontaneous variation of Streptomyces griseus lysing staphylococci].

Spontaneous variation of Str. griseus was studied. 7 variants were isolated which go into the homologous series of the hereditary variability of apigment actinomycetes. The confidence intervals of the correlative relationship between the cultural and morphological features of the spontaneous variants and the level of their lytic activity did not over lap at p 0.95, which indicates that the difference is also significant by this feature. A possibility for a certain increase of the culture activity by selection of spontaneous variants is shown.

Bacteriolysis↗
PubMed1982

[Taxonomy of fluorescent streptomyces based on a comparative population analysis].

A revision of the taxonomy for the fluorescent subgroup of streptomycetes has confirmed experimentally that it is expedient to use the comparative population-taxonomic analysis as a new approach to the taxonomy of actinomycetes, which makes it possible to establish relationships between cultures being compared. It has been shown that the species Streptomyces galbofluorescens and S. fluorescens are merely spontaneous variants in the composition of the parent population of S. chrysomallus and therefore bear no taxonomic and nomenclature status. Consequently, the fluorescent subgroup consists of two (rather than the earlier described four) species: S. chrysomallus and S. citreofluorescens. The names S. galbofluorescens and S. fluorescens should be regarded as synonyms of the name S. chrysomallus. The culture of S. chrysomallus was found to contain a water-soluble antibacterial antibiotic. Three monosynthetic variants were isolated from the population of S. chrysomallus.

Anti-Bacterial Agents↗