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Homologous DNA recombination in eukaryotes is necessary to maintain genome stability and integrity and for correct chromosome segregation and formation of new haplotypes in meiosis. At the same time, genetic determination and nonrandomness of meiotic recombination restrict the introgression of genes and generation of unique genotypes. As one of the approaches to study and induce meiotic recombination in plants, it is recommended to use the recA gene of Escherichia coli. It is shown that the recA and NLS-recA-licBM3 genes have maternal inheritance and are expressed in the progeny of transgenic tomato plants. Plants expressing recA or NLS-recA-licBM3 and containing one T-DNA insertion do not differ in pollen fertility from original nontransgenic forms and can therefore be used for comparative studies of the effect of bacterial recombinases on meiotic recombination between linked genes.

531 patients with non-complicated and non-metastatic colon cancer were operated on during 1995-2008 years. Surgery was radical in all cases. Various types of surgical treatment of the colon cancer, postoperative complications and lethality were analyzed. Open methods reported a 1,6% complications rate and lethality rate was 0,4%. Whereas, laparoscopically operated patients showed the complication rate of 3,6% and lethality was 1,2%. Overall 5-year survival was 91,7% for T1-3N0M0; 75,6% for T4N0M0 and 55,3% for T1-4N1-2M0 stages.

The purpose of the investigation was to study the extension of a physiologic hypoganglionic area in the distal rectum in adults and to define its implication in diagnosing Hirschprung's disease. Thirty-five cadaver distal rectal portions were examined. The extension of a physiologic hypoganglionic area in adults ranged from 7.5 to 50.0 mm (24.4+/-10.9 mm). The authors could determine any element of the intramural nervous system to a level of 40 mm where there was a compact ganglionic deposit with nerve commissures, which is typical of the normal structure of an intermuscular nerve plexus. The extension of a physiologic hypoganglionic area was as large as 40.0 mm in 4 of the 35 cases and 50.0 mm in 1 case. By taking into account these data, it is expedient to use the modified O. Swenson transanal biopsy.

Hybrid genes containing the reporter gene for thermostable lichenase and model genes recA, recA1, cry3a, cry3aM, and ssp1 were constructed. The expression of these genes was studied in prokaryotic and eukaryotic cells. The presence of lichenase in the hybrid proteins was shown to facilitate analysis of the hybrid protein expression in transgenic organisms. Owing to high relative activity and thermostability of lichenase, the activity of this enzyme can be measured by simple, rapid and sensitive qualitative and quantitative methods that do not require costly equipment and reagents. Using the zymograms method, molecular masses of the lichenase-containing hybrid proteins can be precisely estimated. This method is proposed instead of Western blotting using lichenase as a translational reporter. Our results showed that the use of thermostable lichenase as a translational reporter yields the data that are problematic to obtain using traditional methods of gene expression analysis, which is of importance for fundamental and applied research.

Thirty-five autopsied specimens of rectum's distal part and anal canal part were studied. It was revealed that length of physiological hypogangliosis zone ranged from 7.5 to 50.0 mm (mean 24.4+/-10.9 mm). With regard to this wide range the modification of transanal Svenson's biopsy of rectal wall was proposed for diagnosis of malformations of intramural nervous system of the colon. The method was used in 21 patients with megacolon. The results demonstrate accuracy and safety of this diagnostic method.

The misdiagnosis rate in defining the cause of obstructive colonic disease is 8.2-24.4%. This is consistent with the fact that every 5 patients with colonic obstruction present difficulties in establishing the nature of a pathological process. The paper provides the results of analysis of clinical and X-ray symptoms in 350 patients with difficult differentially diagnosed cases of narrowing of the rectum and colon. Based on the analysis, the authors identified the basically important X-ray signs that might differentiate tumor stenoses from other obstructive diseases. They also defined the specific X-ray signs of such diseases as infiltrative cancer; extraintestinal cancer involved in the large bowel; inflammatory strictures in ulcerative colitis, diverticulosis, actinomycosis, tuberculosis, intestinal endometriosis, invagination, and other obstructive diseases. The developed differentiated diagnostic criteria could enhance the overall accuracy of X-ray study in this difficult group of patients from 72.7-80% to 93%.

Seven hundreds and fifty three patients with colon cancer were operated in the Unit of Colon Surgery of the State Scientific Centre of Coloproctology within the period from 1998 to 2003. 352 (46.7%) of them were subjected to systemic chemotherapy. The patients subjected to the surgical and antitumor drug therapy were divided into 3 groups according to the main disease stage: 103 (29.3%) patients with the disease stage T4N0M0 (including those with the tumor local spread), 116 (32.9%) patients with the disease stage T(3-4)N+M0 and 133 (37.8%) patients with the disease stage T(3-4)NxM1. In the patients with the colon serous membrane diffusion and locally spread tumors (total of 103 patients) 3- and 5-year survival was stated in 81.0 +/- 2.8% and 76.5 +/- 3.7% respectively. The control group included 85 patients subjected to the surgical treatment alone. In the latter group 5-year survival was recorded in 68.0 +/- 2.9% of the patients. In the group of the patients with affection of the regional lymph nodes subjected to antitumor drug therapy 3- and 5-year survival was recorded in 64.1 +/- 3.5% and 57.5 +/- 4.2% respectively. In 52 patients not subjected to the systemic chemotherapy the analogous index was equal to 44.5 +/- 3.4%. The systemic chemotherapy was applied to 111 (78.2%) patients with metastases to the liver. In 50 of them cytoreductive operations were performed and in 61 patients palliative resection of the colon was carried out. The average period without clinical manifestations of the disease in the patients subjected to the colon palliative resection and systemic chemotherapy was equal to 8.5 +/- 3.5 months. In the patients with metastases to the liver subjected to the cytoreductive operations the average lifespan after the operations amounted to 24.5 months. The average lifespan of the patients with canceromatosis subjected to the systemic chemotherapy and cytoreductive operations amounted to 13.5 months. When the chemotherapy in such patients was effective the average lifespan was 16 months, while in case of the therapy failure it was 8.5 months.

The efficacy of cytoreductive approach for colon cancer with carcinomatosis was assessed. 34 patients (the main group) underwent colon resections, peritonectomy, omentectomy and intraperitoneal chemotherapy (mitomycin and 5-fluorouracil). 22 patients (control group) underwent palliative colon resections only. The spread of peritoneal dissemination was assessed in all patients, basing on Peritoneal Cancer Index (PCI). It was found, that the rate of postoperative morbidity is higher in the main group, but it was not accompanied by enhanced postoperative mortality. It was also detected, that cytoreductive approach permits to prolong the survival (17.0 +/- 3.5 months in main group vs. 7.5 +/- 2.1 months in controls). The main prognostic factor in these patients was the PCI. The most favorable prognosis is identified if PCI < 5 (few discrete implants are present); the survival in this group was 23.0 +/- 4.5 months and disease-free interval was 14.0 +/- 2.5 months. When PCI was higher then 5, the survival was 14.5 +/- 2.5 months and disease-free interval was 7.0 +/- 1.3 months.

Functional activity of multidrug resistance (MDR) markers (total activity of ABC-transporters, P-glycoprotein (Pgp) and multidrug resistance-associated protein (MRP) activities) in human colon adenocarcinoma and normal mucosa was examined. Functional activity of ABC-transporters was revealed in all colon tumors and in 70% of normal mucosa samples investigated. Expression of Pgp and MRP functional activity was determined in about 50% and 70% of colon tumors respectively. Pgp+MRP+ phenotype was determined in 36% of normal mucosa and adenocarcinoma samples. Expression of Pgp+MRP- phenotype was practically the same in normal mucosa and tumors (in 10 and 18% of samples respectively). Pgp-MRP+ phenotype was revealed two times more often in tumors than in mucosa--in 36 and 18% respectively. On the contrary, Pgp-MRP- phenotype was detected more rarely in tumors than in mucosa (in 10 and 36% of samples respectively). Transporters different from Pgp and MRP were also determined in some tumors and normal mucosa. At the patients with expression of Pgp function in normal mucosa the activity of the transporter was revealed in 25% of tumor samples only. On the contrary, at the patients with expression of MRP function in normal mucosa the activity of the transporter was revealed in 70% of tumor samples. At the patients with no expression of Pgp or MRP activity in normal mucosa the function of the transporters in tumors was determined in 60% and 70% of samples respectively. It is concluded that functional activity of various ABC-transporters (Pgp, MRP and other different from Pgp and MRP) is expressed in human colon adenocarcinoma; expression of ABC-transporters functional activity in normal mucosa does not predict MDR phenotype of the tumor.

A new method for preparing the large intestine for operation is suggested, it is based on oral administration of a solution of polyethylene oxides with chloramphenicol. The preparation possesses a marked hydrophilic activity, which causes inhibition of absorption processes in the lumen of the intestinal tube. This leads to accumulation of the intestinal contents and their quicker passage. Polyethylene oxides also ensure accumulation of antibiotics in the tissues of the intestinal wall. The suggested method was used to prepare the intestine for operation in 93 patients. Comparative evaluation proved its advantages according to the main clinico-laboratory criteria: the method is technically simple, reduces the period of preparation of the intestine, has no negative effect on the homeostasis values, ensures adequate preparation of the large intestine with decrease of the level of its microbial contamination. With the use of the method the number of postoperative purulent complications in interventions on the large intestine reduced.

Combined treatment with the use of intensive methods of preoperative radiotherapy was carried out in 41 patients with malignant tumors of the colon. Study of the specific features of the accomplished surgical interventions and the postoperative management of patients showed that short courses of irradiation on a betatron with energy of 25 MeV, given in 5 daily exposures to a total basic dose of 20 Gy or a single exposure to a basic dose of 7.5 Gy had no unfavourable effect on the performance of the operation and the patients' condition in the postoperative period. The immediate results of the operation were found to be good in all patients.

Single (7.5 Gy) or intensive-concentrated (20 Gy at 5 daily fractions of 4 Gy each) preoperative irradiation was given to 42 colon cancer patients. Operation was performed not later than 24 h after single irradiation and 1-3 days after intensive-concentrated irradiation. Radiation pathomorphosis was studied on histological and electro-microscopic examination of biopsy specimens. Dystrophic changes of tumor cells were noted following the use of both methods, though more noticeable ones were observed after intensive-concentrated irradiation. Obstruction of the microcirculatory bed of a tumor appeared to be a characteristic sign of a tumor stroma response both in single and fractionated irradiation. It was assumed that the latter together with direct radiation damage of tumor cells could be very important to the prevention of implantation recurrences and metastases.

The study discusses the experience gained with application of a complex of methods for early diagnosis of perifocal inflammation in 50 patients with cancer of the colon. Endoscopic, roentgenologic and radionuclide (using 67Ga citrate) methods were mainly employed. Perifocal inflammation was established in 38 (76%) patients. The diagnosis was further confirmed by morphologic examination of resected material. Application of the methods assured early diagnosis of asymptomatic perifocal inflammation associated with tumor.

The study discusses the experience of treatment of 207 patients with locally-advanced cancer of the sigmoid colon who made up 13.5% of the total number of cases of cancer of this site seen in the clinic in 1972-1990. Radical surgery was performed in 170 (82.1%) patients. Postoperative lethality rate was 5.8%, five-year survival rate--70.5 +/- 5.6%. The use of adjuvant preoperative radiotherapy assured a higher resection rate and had no adverse effect on immediate results.

A number of theoretical models have been developed in population genetics to explain the evolution of recombination system under natural selection for adaptive traits. Using Drosophila cage populations of large size the effect of selection for resistance to daily temperature fluctuations on the rec-system was studied in this work. It is established that selection for population adaptability to extreme conditions leads during several tens of generations to significant increase in crossing-over rate within various parts of the genome (especially in b-cn and ru-h of chromosomes 2 and 3), as well as to relaxation of exchange interference for adjacent and non-adjacent segments. The Fisher's theoretical prognosis about tightening of linkage in optimal constant conditions was experimentally confirmed for the first time.

Carcinoma of the right half of the colon (CRHC) is diagnosed in 21-35% of patients with colorectal carcinomas. The Research Institute of Proctology of the RSFSR Ministry of Health has an experience with treatment of 338 patients with CRHC. Most of them (84.9%) were admitted to the clinic with advanced forms of the disease because of poor clinical manifestations at early stages of the disease and resulting in late consultations with the doctor. Surgical treatment was performed in 332 patients. The operation of choice for locally removable tumors of the right half of the colon still remains right-side hemicolectomy. For locally spread CRHC combined operations are thought to be expedient. Immediate results of the surgical treatment of CRHC by the correct curative methods are perfectly favorable, the amount of postoperative complications was 14.5%, lethality--6.6%.

Among 100 patients subjected to a complex examination 44 were found to have Hirschsprung's disease. Operation was fulfilled in 37 patients. Resection of dilated portions of the colon can not be considered to be a radical intervention. With the morphological features of Hirschsprung's disease in adults taken into account, Duhamel's operation is recommended as a readical operation. In patients with a pronounced decompensation of the colon accompanied by ileus the treatment should consist of many steps. In some cases the conservative treatment might be performed under conditions of dispensary observation of the patient.

Surgical treatment of chronic colonic stasis is still a complicated and difficult for solution problem. The undertaken study characterizes one of the causes of chronic constipation in adults--the hypoganglionic variant of Hirschsprung's disease whose clinical course is marked by a prolonged period of compensation while the complex diagnosis is extremely difficult. The severe disorders of the motor-evacuation function of the large intestine make surgery necessary; operation leads to recovery of 96% of patients.

The possibility of evolutionary explanation of dominance relations for alleles in selective-neutral rec-loci was explored by means of numerical experiments. It was shown that selection for two-loci fitness system causing the secondary (induced) selection for the rec-system, results in changing the allele frequency of the second-level modificator gene controlling the dominance relations in the rec-locus. The dominance of rec-allele, providing the favourable for the given conditions level of crossing-over between selected fitness loci, is established, due to these changes. It was found that the neutral dominance modificator can influence the dynamics of the whole system.