[Pelotherapy and pelotherapy combined with intravenous laser blood irradiation at the sanatorium-resort stage of treatment of patients with psoriasis vulgaris]. / Peloidoterapiya i peloidoterapiya v sochetanii s vnutrivennym lazernym osvechivaniem krovi na sanatorno-kurortnom etape lecheniya bol'nykh vul'garnym psoriazom.

Search of new rational ways to increase the effectiveness of treatment and rehabilitation measures for patients with psoriasis vulgaris continues to be one of the urgent problems in modern clinical dermatology. OBJECTIVE: To carry out a comparative analysis of the impact of different variants of sanatorium-resort treatment (SRT) - pelotherapy and pelotherapy in combination with intravenous laser blood irradiation (ILBI) - on the level of IL-17 and TNF-a, dermatological status, psychoemotional state and quality of life (QL) assessment of patients with psoriasis vulgaris. MATERIAL AND METHODS: A naturalistic comparative study included 120 patients with psoriasis vulgaris, who were undergoing SRT: 57 patients in the pelotherapy group and 63 in the group of pelotherapy in combination with ILBI. The SRT effectiveness was assessed using the PASI index, the HARS and HDRS scales and the DLQI questionnaire. The dynamics of IL-17 and TNF-a plasma levels in blood plasma was studied. The study duration was 6 months 14 days. RESULTS: After 14 days of SRT, a decrease in IL-17 and TNF-a levels in blood plasma was statistically significant both in the pelotherapy group and in the group of pelotherapy in combination with ILBI, no statistically significant differences between the groups were found. Furthermore, the comprehensive use of pelotherapy in combination with ILBI has contributed to a more pronounced statistically significant decrease in the PASI index, the HARS and HDRS scales' total scores and an increase in the level of QL. The number of patients with clinical remission was statistically higher in the group of pelotherapy combined with ILBI compared to the pelotherapy group (87.3% versus 42.1%) six months after SRT. CONCLUSION: The advantage of comprehensive application of pelotherapy and ILBI in comparison with pelotherapy in patients with psoriasis vulgaris in SRT has been shown. The comprehensive application of pelotherapy and ILBI reduces the level of inflammatory biomarkers, improves dermatological and psychoemotional status, improves QL and is well tolerated by patients.

Study on the role of nano antibacterial materials in orthodontics (a review) / Estudo sobre o papel dos materiais nanoantibacterianos na ortodontia

Nanoparticles (NPs) are insoluble particles with a diameter of fewer than 100 nanometers. Two main methods have been utilized in orthodontic therapy to avoid microbial adherence or enamel demineralization. Certain NPs are included in orthodontic adhesives or acrylic resins (fluorohydroxyapatite, fluorapatite, hydroxyapatite, SiO2, TiO2, silver, nanofillers), and NPs (i.e., a thin layer of nitrogen-doped TiO2 on the bracket surfaces) are coated on the surfaces of orthodontic equipment. Although using NPs in orthodontics may open up modern facilities, prior research looked at antibacterial or physical characteristics for a limited period of time, ranging from one day to several weeks, and the limits of in vitro studies must be understood. The long-term effectiveness of nanotechnology-based orthodontic materials has not yet been conclusively confirmed and needs further study, as well as potential safety concerns (toxic effects) associated with NP size.

Nanopartículas (NPs) são partículas insolúveis com diâmetro inferior a 100 nanômetros. Dois métodos principais têm sido utilizados na terapia ortodôntica para evitar a aderência microbiana ou a desmineralização do esmalte: NPs são incluídas em adesivos ortodônticos ou resinas acrílicas (fluoro-hidroxiapatita, fluorapatita, hidroxiapatita, SiO2, TiO2, prata, nanopreenchimentos) e NPs são revestidas nas superfícies de equipamentos ortodônticos, ou seja, uma camada fina de TiO2 dopado com nitrogênio nas superfícies do braquete. Embora o uso de NPs em ortodontia possa tornar acessível modernos recursos, pesquisas anteriores analisaram as características antibacterianas ou físicas por um período limitado de tempo, variando de 24 horas a várias semanas, por isso devem ser compreendidos os limites dos estudos in vitro. A eficácia de longo prazo de materiais ortodônticos com base em nanotecnologia ainda não foi confirmada de forma conclusiva, o que exige mais estudos, bem como potenciais preocupações de segurança (efeitos tóxicos) associadas ao tamanho da NP.

Study on the role of nano antibacterial materials in orthodontics (a review)

Abstract Nanoparticles (NPs) are insoluble particles with a diameter of fewer than 100 nanometers. Two main methods have been utilized in orthodontic therapy to avoid microbial adherence or enamel demineralization. Certain NPs are included in orthodontic adhesives or acrylic resins (fluorohydroxyapatite, fluorapatite, hydroxyapatite, SiO2, TiO2, silver, nanofillers), and NPs (i.e., a thin layer of nitrogen-doped TiO2 on the bracket surfaces) are coated on the surfaces of orthodontic equipment. Although using NPs in orthodontics may open up modern facilities, prior research looked at antibacterial or physical characteristics for a limited period of time, ranging from one day to several weeks, and the limits of in vitro studies must be understood. The long-term effectiveness of nanotechnology-based orthodontic materials has not yet been conclusively confirmed and needs further study, as well as potential safety concerns (toxic effects) associated with NP size.

Resumo Nanopartículas (NPs) são partículas insolúveis com diâmetro inferior a 100 nanômetros. Dois métodos principais têm sido utilizados na terapia ortodôntica para evitar a aderência microbiana ou a desmineralização do esmalte: NPs são incluídas em adesivos ortodônticos ou resinas acrílicas (fluoro-hidroxiapatita, fluorapatita, hidroxiapatita, SiO2, TiO2, prata, nanopreenchimentos) e NPs são revestidas nas superfícies de equipamentos ortodônticos, ou seja, uma camada fina de TiO2 dopado com nitrogênio nas superfícies do braquete. Embora o uso de NPs em ortodontia possa tornar acessível modernos recursos, pesquisas anteriores analisaram as características antibacterianas ou físicas por um período limitado de tempo, variando de 24 horas a várias semanas, por isso devem ser compreendidos os limites dos estudos in vitro. A eficácia de longo prazo de materiais ortodônticos com base em nanotecnologia ainda não foi confirmada de forma conclusiva, o que exige mais estudos, bem como potenciais preocupações de segurança (efeitos tóxicos) associadas ao tamanho da NP.

[Perioperative prevention of complications in surgery of ventral hernias]. / Perioperatsionnaya profilaktika oslozhnenii v khirurgii ventral'nykh gryzh.

OBJECTIVE: To improve perioperative algorithm of prevention of complications in patients with ventral and incisional hernias via differentiated choice of mesh implants and hernia repair technique. MATERIAL AND METHODS: The study included 144 patients with abdominal wall hernia, who were divided into two representative groups. RESULTS: Original algorithms for choosing the method of hernia repair depending on type and position of mesh implant, as well as methods of perioperative prevention of complications are proposed. CONCLUSION: These algorithms significantly reduced the incidence of postoperative wound complications after sublay hernia repair and posterior separation with TAR.

Epidemiological characteristics of uropatogenic isolates of Escherichia coli in hospitals.

The aim of the study was to evaluate the genetic affinity of uropathogenic E. coli cultures (UPEC) and to identify the major types of extended spectrum beta-lactamases (ESBL) found among nosocomial isolates. A molecular typing of UPEC (n=93) isolated from patients with urinary tract infections (UTI) who were hospitalised in nine medical facilities (MO) in Perm was performed. It was found that 69.89% of the cultures had individual RAPD/ERIC profiles, the remaining 30.10% were distributed among 13 genome groups. Most frequently blaCTX-M-1 was detected individually or in combination with other beta-lactamase genes (n=23, 79.31% of ESBL phenotype-positive isolates), genes were detected in seventeen cases (58.62%) blaTEM and/or blaOXA, the blaCMY fragment was found in only three isolates (10.34%), blaSHV was missing in this isolates. It was shown that in two thirds of the cases the pathogens of the infection process are representatives of the endogenous intestinal microbiota of the patients, in other cases an exogenous infection occurs. The proportion of "circulating" (possibly hospital) isolates in the spectrum of UTI increased in the series: therapy departments - surgery departments - intensive care units. In addition, in multidisciplinary hospitals there are conditions for cross-infections of patients, but the epidemiological chains of episodes of UTI are short and concise. It has been shown that the probability of infection with E. coli producing CTX-M or OXA enzymes is significantly higher in the intensive care unit than in surgery or therapy departments. The data obtained complement the understanding of the epidemiology of UTI caused by E. coli and can be used as an aid in the planning and implementation of methods for the prevention and control of nosocomial UTI.

[Risk factors of abdominal wound dehiscence in abdominal surgery]. / Faktory riska razvitiya eventratsii v abdominal'noi khirurgii.

OBJECTIVE: To evaluate the role of various perioperative risk factors on the incidence of abdominal wound dehiscence. MATERIAL AND METHODS: A retrospective controlled randomized trial of the risk factors of abdominal wound dehiscence was conducted in 62 patients for the period 2013- 2018. The research was performed at the Perm City Clinical Hospital No. 4. All patients were divided into two groups: the main one (n=31) with abdominal wound dehiscence in early postoperative period and the control group (n=31) without this event. Both groups were comparable by gender, age and surgical abdominal diseases. Between-group differences in numerical indicators were analyzed using Mann-Whitney U-test, qualitative variables were analyzed using contingency tables. Differences were significant at p-value <0.05. RESULTS: Incidence of abdominal wound dehiscence was similar in patients who admitted in emergency and elective fashion (p=0.54). Anemia upon admission (p=0.71), diabetes mellitus type 2 (p=1.00), COPD (p=0.13) and obesity (p=0.76) were not significant predictors of abdominal wound dehiscence. There were significant between-group differences in CRP level (p=0.04). Among intraoperative risk factors, duration of surgery (p=0.78), surgical approach (p=1.00), aponeurosis suturing technique (p=0.39) and stoma (p=0.71) did not significantly affect the incidence of abdominal wound dehiscence. In early postoperative period, abdominal wound dehiscence correlated with peritonitis (p=0.04), SSI (p<0.01) and redo laparotomy (p=0.02). CONCLUSION: Despite the variety of pre-, intra- and postoperative risk factors, only infectious postoperative complications (SSI, peritonitis) and redo surgical interventions influenced the development of abdominal wound dehiscence. Thus, the concept of abdominal wound dehiscence prevention should be inextricably associated with the concept of prevention of postoperative infectious complications from the abdominal wall and abdominal cavity.

Evaluation of Antitumor Efficiency of High Intensity Radiation 169Yb Source on Experimental Sarcoma M-1.

Rats with sarcoma M-1 were exposed to high dose rate irradiation with 169Yb source. In 25 days after introduction of a trocar with sealed capsule with 169Yb source into the tumor, complete tumor regression was observed in 70% animals. The results suggest feasibility of using 169Yb source for high-dose rate brachytherapy and development of the personalized medicine approaches.

Phenotypic and functional characteristics of dendritic cells and contents of suppressor cell populations in peripheral blood of breast cancer patients.

The progression or the appearance of distant metastases in breast cancer (BC) is influenced by a variety of antitumor immune response suppression mechanisms. In this paper we study circulating dendritic cells (DC) and the suppressor cell populations in peripheral blood of breast cancer patients. The study of phenotypic and functional properties of DCs was performed in the samples of intact and TLR-stimulated whole blood from breast cancer patients and healthy women by multicolor flow cytometry. To determine the suppressor cell population among lymphocytes multicolor panel comprising markers CD 4, CD 25, CD 127, FoxP3 was used. It is showed that the formation of secondary foci of tumor growth in patients was accompanied by disturbances of the functional activity plasmocytoid DC and accumulation of cells with immunosuppressive functions.

[Radioprotective Properties of NO-synthase Inhibitor T1023: II. The Ability for Selective Protection of Normal Tissues During Radiotherapy of Tumors].

We studied the effect of T1023, NO-synthase inhibitor, N-acyl-S-alkyl-isothiourea in a single administration at a dose of 75 mg/kg on the growth of transplantable rat sarcoma M-1 and the development of acute skin reactions after the local impact of γ-radiation at the doses of 32 and 36 Gy. The results showed that the T1023 at a single dose had no effect on the growth of sarcoma, and did not modify the radiosensitivity of the tumor and anti-tumor efficacy of γ-rays. However, at both doses T1023 significantly reduced the severity of acute radiation skin reactions. NOS inhibitor did not change the duration of the inflammatory and regenerative processes, but significantly limited the degree of radiation alteration of the deep layers of the skin and underlying tissues. The findings suggest that the hypoxic mechanism of antitumor action allows T1023 to selectively protect the non-malignant tissue during radiation therapy of solid tumors. Therefore, this compound may be regarded as a promising basis for the development of pharmacological prevention of radiotherapy complications.

[Evaluation of biological properties of Pseudomonas aeruginosa strains isolated from patients with sternum and rib osteomyelitis].

AIM: Study of the role of P. aeruginosa in the development of osteomyelitis of sternum and ribs in cardio-surgery patients, and analysis of the main biological properties of the isolated bacterial strains. MATERIALS AND METHODS: 132 bacterial cultures were isolated from 83 hospital patients as a result of bacteriological examination during 2007-2013. Wound discharge was the study mate- rial. Sampling, seeding and identification of the isolated cultures was carried out by using the respective test-systems; antibiotic sensitivity was studied by disc-diffusion method. RESULTS: The proportion of P. aeruginosa was 10.6% (n = 14) that is comparable with data on wound infections of general surgery hospitals. A direct and strong correlation (R = 0.846, p = 0.000132) between hemolytic and phospholipase activity was established during evaluation of virulence properties of the isolated-strains. The degree of film-forming ability varied significantly from 0.122 to 1.412 OD; 64.3% ofthe studied cultures were highly film-forming variants. Statistically significant association between biofilm formation and other studied properties was not found. 4 strains produced VIM2-type metallo-betalactamase and had identical RAPD profiles. CONCLUSION: Considering that earlier the similar cultures were not detected and all of them were isolated at a short interval of time, we have made a conclusion, that their short-term circulation is probably associated with introduction, which was the reason for patient infection. P. aeruginosa could be the etio-pathogen of both early and later complications of cardio-surgical interventions.

[Influence of Chlorhexidine and Prontosan on Dual Species and Monospecies Biofilms Formed by Staphylococcus aureus and Pseudomonas aeruginosa].

The effect of two antiseptics, i. e. chlorhexidine bigluconate 0.5% solution and Prontosan on dual species and monospecies biofilms formed in vitro by the reference strains P. aeruginosa ATCC 27853 and S. aureus ATCC 29213 was examined. It was demonstrated by atomic force microscopy that under the biocide action there occurred phenotype changes of the structural organization of the bacterial biofilms and morphology of the sessile cells: the cocci were lesser in diameter and the rods were reduced. A reliable change of linear cell sizes was accompanied by increase of their roughness (Sq) that was more pronounced for Prontosan. When assessing the cell viability it was found that Prontosan inhibited the bacterial viability in mixed and monospecies biofilms formed on both hydrophilic and hydrophobic abiotic surfaces. In the latter case the biofilm biomass (determined by crystal violet assay) lowered in all the variants of the experiment.

[The effectiveness of fractionated exposure of sarcoma M-1 to gamma-radiation and fast neutrons].

The effectiveness of fractionated exposure to gamma- and neutron radiation in their separate and combined use on the growth and functional morphology of mutant p53 sarcoma M-1 in rats was studied. Investigation techniques included immunostaining of PCNA and mutant p53 expressing cells, determination of mitotic activity and apoptotic death of tumor cells, as well as computer analysis of microscopic images. The antitumor efficacy of different types of radiation is shown to be determined by different levels of apoptosis induction, reduced proliferation and cellularity. Neutron radiation of the impulse generator has a marked damaging effect on the vasculature and the development of tumor necrosis. Fractionated irradiation at equal daily doses led to the decrease in the relative effectiveness of radio-inactivation of tumor cells. After 9 fractions of irradiation, the calculated value of the RBE of fast neutrons normalized to the input dose of 1 Gy by the coefficient of tumor growth inhibition, a reduced proliferative activity of PCNA and induced apoptosis of tumor cells was 3.4, 3.7 and 3.1, respectively. In the mode of daily superfractionation with splitting the dose in two fractions, the effectiveness of the combined exposure corresponded to the additive effect of gamma- and neutron radiation with a tendency toward synergism. There are reasons to believe that high resistance of sarcoma M-1 to the ionizing radiation impact is due not only to a fraction of hypoxic cells, but also the mutant status of p53 gene.

[Non-ST-elevation acute coronary syndrome. Comparison of effects of atorvastatin and rosuvastatin on blood levels of lipids and markers of inflammation].

UNLABELLED: Data on rapid effects of statins in patients (pts) with acute coronary syndrome (ACS) are mostly from trials of atorvastatin (ATO). We hypothesized that due to high potency 10 mg of rosuvastatin (ROS) would produce same changes of lipids and inflammation markers as 40 mg ATO. METHODS: We openly randomized 53 pts (69.7+/-10.1 years, 58.5% - man) within 36 h of non ST elevation (NSTE) ACS (56.6% NSTE myocardial infarction) to ROS 10 (n=19), ATO 40 (n=19) mg/day or no statin (n=15). Pts with low density lipoprotein cholesterol (LDL-C) >6, triglycerides (TG) >4.5 mmol/l, C-reactive protein (CRP) >10 mg/l (non-fasting sample) were not included. LDL-C, high density lipoprotein (HDL)-C, TG, apolipoproteins A-1 (apoA), and B (apoB), high sensitivity CRP, tumor necrosis factor-alpha (TNFalpha), interleukin-6 (IL-6) were measured in fasting blood sampled at randomization and 2 weeks later. RESULTS: Both statins caused similar decreases of LDL-C (-44.0% ROS, -50% ATO; both p<0.00001 vs control [-4%]). TG significantly rose in ROS (p=0.042) and control (p=0.008) groups but not in ATO group (p=0.615). HDL-C decreased similarly in 3 groups. ApoA-1 did not differ between 3 groups at all time points. ApoB decreased more in ATO (-32.6%), than in ROS (-24%) group (p=0.049). CRP and IL-6 changes from baseline were insignificant. In ROS group CRP had tendency to decrease but same tendency took place in control. TNFalpha significantly increased in all groups. There were no significant differences between 3 groups in inflammation markers. CONCLUSION: In pts with NSTEACS effect on lipids of ROS 10 mg was somewhat inferior to ATO 40 mg/day. Unexpectedly ATO and ROS during first 14 days of NSTEACS produced no significant effect on inflammation markers possibly because of insufficient dose of both.

[Some kinetic characteristics of cervical cancer].

Proliferation parameters such as mitotic index, tumor growth rate and cell loss were identified in 1,048 squamous cervical carcinoma patients treated at the Center's Clinic (1951-1996). Mitotic indices ranged 0.2-5.1% (average 1.13 +/- 0.03%), Ki-67--4.1-97.8% (average 49.97 +/- 3.02%). A direct and significant correlation between the two latter parameters was established. Cell loss levels ranged 59-99.9% (average 97.2 +/- 0.002%). Our results suggest that the correlation between tumor growth rate and cell loss might be of the utmost importance among the other prognostic factors.

[Immunohistochemical markers as prognosticators in gynecologic oncology].

Cyclooxygenase and particularly COX-2 expression impaired survival in patients operated on for endometrial adenocarcinoma of the uterus: 5-year overall and relapse-free survival in absence of expression was 92% and 88%, respectively, while in cases of distinct expression, it fell down to 52% and 48%, respectively (p = 0.0004; 0.0005). Similar correlations were observed for COX-1, although with lower significance (p = 0.02). Particularly unfavorable prognosis is associated with high expression of combination of COX-2 and COX-1. The end-results of radiotherapy were associated with proliferative levels of squamous cell cervical carcinoma: for Ki-67--below median of < or = 50%, 5-year survival rate was 77%, mean survival--80 months; for Ki-67 above median of > or = 50%, the indices were 47% and 47 months, respectively, (p = 0.002). There were similar correlations for mutated suppressor-gene 53: 67%--for absence of expression and 53%--for its presence (p = 0/03). Immunohistochemical markers COX-2, Ki-67 and p53 can be used as sole prognosticators and their predictive significance is higher than that of either stage (II or III) or cell differentiation grading.

[Clinical value of the local parameters of lipid peroxidation and antioxidative defense in patients after cataract extraction].

The postoperative period of cataract extraction and the parameters of lipid peroxidation (LPO) (dienic conjugates, TBA-active compounds) and the antioxidative activity (AOA) of tear were studied in 77 patients in relation to the type of a surgical intervention--extracapsular cataract extraction (ECCE) and phacoemulsification (PE). The incidence of severe postoperative uveitis was more than 3 times higher on days both 1 and 5 after surgery. Tear studies revealed a significant increase in the concentration of LPO products just on day 1, with its further slight increase by day 5 along with a further significant reduction in AOA, which indicates the significant consumption of antioxidative defense components and the expediency of using antioxidants. Comparison of tear biochemical parameters revealed no difference in patients after ECCE and PE. Thus, peroxidation processes reflect the severity of an inflammatory reaction in the early postoperative period, the study of the processes in tear is a noninvasive, high-informative method for recording the balance of LPO and antioxidative defense processes, which will assist in determining the direction of therapeutic measures to improve the outcome of a surgical intervention.

[Immunohistochemical study of the predictive value of oncoproteins p53, HER-2 and c-myc during radiotherapy for squamous cell carcinoma of the cervix].

Out of 80 patients with squamous cell cervical carcinoma (stage II-III), p53 expression was observed in 30% of tumors prior to treatment and 49% in the course of radiotherapy. A correlation between degree of p53 expression before treatment, on the one hand, and overall and recurrence-free survival, on the other, was identified: high expression of mutated gene-suppressor p53 was 53% while for absence or low expression, it rose to 67% (p=0.03). For overexpression, 20-month survival was 65%; absence--81% (p=0.01). Hence, p53 expression may be used as a predictive factor in radiotherapy for cervical carcinoma. No correlation was found between p53 expression, on the one hand, and such basal clinico-morphological parameters as stage, morphological pattern and tumor cell differentiation, on the other. HER2(3t) overexpression occurred in 2 (2.5%) which seems to point to its insignificant role in squamous cell cervical carcinoma. There was no relationship between c-myc expression and long-term results.

[Ki-67 expression as a predictor of the effectiveness of radiotherapy and of outcome in locally advanced squamous cell carcinoma of the uterine cervix (immunohistochemical study)].

Retrospective immunohistochemical assay of antigen Ki-67 in tumor tissue was carried out prior to and in the course of radiotherapy (TFD - 14-20Gy) in 89 patients with squamous cervical carcinoma. Index of proliferation, i.e. number of Ki-67-positive cells per 1,000 of all cells, was found. Prior to therapy, the index was on the average 49.7%, during irradiation it decreased and its mean value was 24%. There was a correlation between proliferation level tumor progression and the former influenced the immediate effect of radiotherapy. Ki-67 expression in cervical carcinoma exceeded the median. It correlated with unfavorable end-results and was followed by higher relapse incidence. No significant proliferation index difference was reported visa-vis histological pattern, tumor cell differentiation or age. Yet, the drop in proliferative activity during therapy was significant, regardless of outcome. Our results pointed to the high prognostic significance of proliferative activity as far as therapy and outcome were concerned.

The clinical diagnosis of cranial nerve injuries at operations on the carotid arteries.

Operation on the carotid arteries (CA) prevent strokes in patients with occlusions and stenoses of these arteries. We have worked out the measures for preventing perioperative strokes. During interventions on the CA, iatrogenic injuries to the cranial nerves (CN) are paid little attention. 1186 patients underwent 1362 operations. There were 26 lethal outcomes and 38 strokes. 146 (0.7%) cases of CN injuries were documented. Of these, there were 2 (0.1%) injuries to the accessory nerve, 14 (1%) to the glossopharyngeal nerve, 28 (2%) to the hypoglossal nerve, 46 (3.4%) injuries to vagal nerve branches, and 56 (4.2%) to facial nerve branches. In 42 patients, neuropathies acquired the 'permanent' character. We describe the symptomatology of injuries to different CN pairs consequent on carotid operations and the algorithm of their diagnosis. CN injuries deteriorate the results of operations and decrease quality of life of the patients. Early diagnosis and correction of the sequelae of iatrogenic injuries to the CN is a reserve for the refinement of the results of operations on the CA.

[Growth kinetics and functional morphology of M-1 sarcoma in rats before and after gamma-irradiation]. / Kinetika rosta i funktsional'naia morfologiia sarkomy M-1 u intaktnykh krys i posle gamma-oblucheniia.

The study was concerned with growth of sarcoma M-1 and basic morphological characteristics of proliferative activity of cells of this strain as well as apoptosis of cells at different stages of tumor progression in rats before and after a single gamma irradiation at 30 Gy. At the parenchymal periphery which determines tumor growth, the PCNA index of proliferating cells was 76.5%; spontaneous cell death--0.28%. During post-irradiation period, the sarcoma PCNA index fell to 62.3% while the apoptotic index rose five-fold. These findings support the concept of radiation-induced apoptosis being a major pathogenetic factor responsible for effectiveness of radiotherapy of tumors. Indirect evidence on PCNA immunostaining suggested that synthesis of this cyclin is sensitive to the level of oxygen input in the cell, yet it offers sufficient resistance to gamma-radiation.