Flexible intramedullary nails for limb lengthening: a comprehensive comparative study of three nails types.

This study aims to investigate the comparative study of calcium phosphate coatings for flexible intramedullary nails (FINs) used to lengthen long tubular bones. The presence of a calcium phosphate coating deposited by micro-arc oxidation (MAO) or a composite coating based on a co-polymer of vinylidene fluoride with tetrafluoroethylene (VDF-TeFE) and hydroxyapatite (HA) on the surface of the FIN significantly enhanced the regeneration of bone in the area of osteotomy during limb lengthening by combined osteosynthesis. The investigation of the physico-chemical properties of the FIN coated with calcium phosphate via MAO demonstrated that the improved bone tissue formation resulted from favourable conditions for adhesion, proliferation and differentiation of multipotent stem cells into osteoblasts on the coating surface. The composite coatings only stimulated the formation of bone tissue in vivo, primarily because of the piezoelectric properties of the VDF-TeFE co-polymer.

[Effect of flavonoids on the composition of surface glycopolymers in Azospirillum lipoferum Sp59b].

Cultivation of the type strain Azospirillum lipoferum Sp59b in the presence of the flavonoid quercetin induced modification of the structure of the bacterial lipopolysaccharide. Cultivation in the presence of the flavonoid was shown to result in altered serological characteristics of the bacteria, increased heterogeneity of the outer membrane lipopolysaccharide pool, as well as in modified composition and fatty acid ratio of lipid A. The flavonoid was shown to induce the synthesis of the O-specific polysaccharide with the repeating structure represented by a tetrasaccharide consisting of a linear trisaccharide fragment of α-L-Rhap residues in the main chain and the terminal ß-D-Glcp residue. The structure of this O-specific polysaccharide was identical to the previously determined structure of the capsular polysaccharide of these bacteria grown without quercetin. Modifications in the structural composition of the capsular polysaccharide induced by cultivation in the presence of quercetin were revealed.

[Lymph node dissection in early ovarian cancer].

AIM: Our aim was to evaluate and summarize our experience in surgical treatment for early ovarian cancer, the way and extend of metastases, as well as the need and effectiveness of applying radical pelvic and paraaortic lymph node dissection. We compared our results with the results of prominent clinics all over the world in this special field. MATERIAL AND METHODS: We researched retrospectively patients, operated for early ovarian cancer for 15 years period. We evaluated the use of lymph node dissection and the level of its radicality. Examining the volume and borders of the lymph node dissection we tried to sintesize the main practical conclusions and refferences, which can be applied practically by the colleagues working in gynaecological and oncogynaecological clinics in our country RESULTS: According to us and the most foreign authors the ovarian cancer, must be removed intact, and frozen section biopsy must be used. The surgical staging includes: total abdominal histerectomy, bilateral salpingooophorectomy and total pelvic and/or paraaortic lymph node dissection. The surgical staging in all patients is obligatory and includes: a) cytological examination of ascites. b) when ascites is absent--cytological smear. c) Examination of intraabdominal organs and surfaces. d) Biopsies are taken from all suspicious regions. e) The diaphragm is examined by biopsy and scraping. f) Infracolic omentectomy is performed. g) Retroperitoneal spaces are dissected and examined. h) The paraaortal area is examined. When enlarged lymph nodes are found--they are resected and examined. If enlarged paraaortal lymph nodes are found--total paraaortic lymph node dissection is performed. DISCUSSION: The extend of the lymph node dissection in early ovarian cancer is connected with better survical rate in these patients. CONCLUSIONS: The lymph node dissection helps for precise surgical staging in early ovarian cancer. The volume of the lymph node dissection is significant prognostic factor for better survical rate, as well as age, stage, histological type and the grade of the disease.

IS THERE A ROOM IN BULGARIA FOR RADIOTHERAPY OF GASTRIC CANCER?

Gastric cancer is the fourth most common cancer worldwide with one million new casesyearly and the second most frequent cause of cancer death. Although surgery is the leading treatment modality of gastric cancer the survival remains low (5- year survival is reported to be 25% in Europe and 60% in the Eastern world). The risk of locoregional recurrence grows with the increase of the tumor stage. In order to improve locoregional control a number of clinical studies in the last four decades have examined different strategies of adjuvant therapy, including chemotherapy, radiotherapy, chemoradiation with ambiguous results. Various regimens of radiotherapy alone, applied preand postoperatively or in combination with chemotherapy in pre- and postoperative settings have been studied. With the present article, the authors present the world experience of radiotherapy application in gastric carcinoma, supporting its introduction in to Bulgarian clinical practice. The study results concerning this topic have been discussed. SWOG/Intergroup 0116 study showed that postoperative chemoradiation leads to increased 5-year overall survival compared with surgery alone. A recent metaanalysis on randomized trials in operable gastric cancer, found that adjuvant radiotherapy leads to 20 % improvement in disease free survival and overall survival and found no subgroup of patients who do not benefit from adjuvant radiotherapy. The available data from the published studies and metaanalysis completely supports the introduction of chemoradiation for gastric cancer and in Bulgarian radiotherapy practice with the opportunity of gaining own experience.

Radiotherapy in the multimodality management of esophageal cancer.

Squamous cell carcinoma and adenocarcinoma of the esophagus represent more than 90% of all cases of esophageal carcinoma. Although the incidence of squamous cell carcinoma has decreased, a continues increase in the incidence of adenocarcinoma has been observed, due to the increasing rate of obesity and gastroesophageal reflux disease. Treatment of carcinoma of the esophagus is complex and include surgery, chemotherapy and radiotherapy. The authors investigate the role of radiotherapy in the modern multimodality treatment of esophageal carcinomain order to derive recommendations for its implementation. The results of clinical trials and meta-analysis dealing with the radiotherapy application alone or as chemoradiation in preoperative, postoperative or definitive settings are summarized. When summarizing the data from the clinical trials and the meta-analyzes in esophageal carcinoma radiotherapy recommendations are drawn up. As a single modality radiotherapy is recommended only in palliative setting. Current data indicates that the neoadjuvant chemoradiation followed by the surgery is accepted as a standard treatment achieving 3-year overall survival rateraging between 30% and 60%. No improvement in local control or survival is observed when total irradiation dose is increased over 50.4Gy. Neoadjuvant or definitive chemoradiation became a standard treatmentin locally advanced tumors of the esophagus. Preoperative chemoradiation has proven contribution to improving treatment results when compared to surgery alone in both squamous cell and adenocarcinoma of esophagus. There is also a trend towards improved survival when neoadjuvant chemoradiation is applied compared to neoadjuvant chemotherapy alone. Data in favor of definitive radiotherapy as radical treatment are limited and its use is recommended only in case of palliation.

[Characterization of the lipopolysaccharides of serogroup II Azospirillum].

Lipopolysaccharides of six Azospirillum strains (A. brasilense SR50, SR80, SR88, SR109, SR111, SR115, and A. lipoferum SR 42) isolated from the rhizosphere of cereal plants of Saratov oblast, Russia and assigned to serogroup II by serological analysis were studied. In the lipid A fatty acid composition, the lipopolysaccharides under study were similar to those of other Azospirillum strains and were characterized by predominance of 3-hydroxytetradecanoic, 3-hydroxyhexadecanoic, and octadecenoic acids. Monosaccharide analysis of the O-specific polysaccharides (including determination of the absolute configurations, methylation analysis, and one- and two-dimensional NMR spectroscopy) revealed the presence of two types of repeating units in varying ratios. High degree of serological similarity between the strains under study was shown to result from the presence of repeating units with identical structure in their O antigens.

Variability of the biological activity of oxidized titanium implants.

Oxidized titanium is a biologically inert material, but bioinertness reduces biomechanical characteristics of titanium implants. Modification of the structure of oxide surface layer of BT 5-1 titanium by increasing its thickness (by 1.7 times) and pore diameter (by 1.4 times) and by adding phosphorus, aluminum, and zinc oxides to its composition leads to radical modification of its biological characteristics. These implants acquire osteoinductive properties in in vivo systems not found in pure or oxidized BT 1-00 titanium and fairly well maintain in vitro growth of mesenchymal cells.

Structural peculiarities of the O-specific polysaccharides of Azospirillum bacteria of serogroup III.

Lipopolysaccharides and O-specific polysaccharides were isolated from the outer membrane of bacterial cells of three strains belonging to two Azospirillum species, and their structures were established by monosaccharide analysis including determination of the absolute configurations, methylation analysis, and one- and two-dimensional NMR spectroscopy. It was shown that while having the identical composition, the O-polysaccharides have different branched tetrasaccharide repeating units. Two neutral polysaccharides were found in the lipopolysaccharide of A. brasilense 54, and the structure for the predominant O-polysaccharide was determined. The structural data, together with results of serological studies, enabled assignment of strains examined to a novel serogroup, III. The chemical basis for the serological relatedness among the azospirilla of this serogroup is presumably the presence of a common →3)-α-L-Rhap-(1→2)-α-L-Rhap-(1→3)-α-L-Rhap-(1→ oligosaccharide motif in their O-polysaccharides.

[The value of endo rectal ultrasound].

In the last twenty years, endorectalultrasound (ERUS) has become the primary method for locoregional staging of rectal cancer. ERUS is the most accurate modality for assessing local depth of invasion of rectal carcinoma into the rectal wall layers (T stage). Lower accuracy for T2 tumors is commonly reported, which could lead to sonographic overstaging of T3 tumors following preoperative therapy. Unfortunately, ERUS is not as good for predicting nodal metastases as it is for tumor depth, which could be related to the unclear definition of nodal metastases. The use of multiple criteria might improve accuracy. Failure to evaluate nodal status could lead to inadequate surgical resection. ERUS can accurately distinguish early cancers from advanced ones, with a high detection rate of residual carcinoma in the rectal wall. ERUS is also useful for detection of local recurrence at the anastomosis site, which might require fine-needle aspiration of the tissue. Overstaging is more frequent than understaging, mostly due to inflammatory changes. Limitations of ERUS are operator and experience dependency, limited tolerance of patients, and limited range of depth of the transducer. The ERUS technique requires a learning curve for orientation and identification of images and planes. With sufficient time and effort, quality and accuracy of the ERUS procedure could be improved.

[Influence of FDG-PET-CT on diagnostic and treatment of colorectal cancer].

INTRODUCTION: In patients with colorectal cancer (CRC), preoperative evaluation and staging should focus on techniques that might alter the preoperative or intraoperative surgical plan. The aim of this study was to evaluate the utility of FDG-PET-CT modality in the initial staging of patients with CRC in comparison with conventional staging methods and to determine its impact on therapeutic management. METHODS: One hundred and four patients with a diagnosis of CC, selected prospectively, were studied for staging using a standard procedure (CT) and FDG-PET-CT. All the patients were morphologically verificated by histology. RESULTS: In 14 patients, surgery was contraindicated by FDG-PET-CT owing to the extent of disease (only 6/14 suspected by CT). FDG-PET-CT revealed four synchronous tumours. For N staging, both procedures showed a relatively high specificity but a low diagnostic accuracy (PET 60%, CT 64%) and sensitivity (PET 28%, CT 35%). For M assessment, diagnostic accuracy was 94% for FDG-PET-CT and 86% for CT. FDG-PET-CT evaluation led to modification of the therapy approach in 50% of patients with unresectable disease. FDG-PET-CT findings were important, revealing unknown disease in 19.2%, changing the staging in 13.46% and modifying the scope of surgery in 11.54% (with a change in the therapeutic approach in 17.85% of those patients with rectal cancer). CONCLUSION: Compared with conventional techniques, FDG-PET-CT appears to be useful in pre-surgical staging of CC, revealing unsuspected disease and impacting on the treatment approach.

[Determination of phage resistance of E. coli cells with electrooptical analysis of cell suspensions].

Changes in the electrooptical (EO) properties of cell suspensions of the E. coli strains: XL-1, BL-Ril, TG-1, K-12, B-878, and BL-21 (DE) in their contamination with the bacteriophage M13K07 were studied depending on the time of infection. The phage-induced specific changes in the EO parameters of cell suspensions were ascertained to occur only in the E. coli strains XL-1, TG-1, and K-12 whereas these changes were not seen in the cell suspensions of E. coli strains BL-Ril, B-878, BL-21 (DE). Control experiments were carried out to infect the cells with the bacteriophage, by making a standard inoculation of the dense nutrient media. The fact that the method for EO analysis of cell suspensions may be used to determine the phage resistance of microbial cells is first shown.

Capsular polysaccharide of the bacterium Azospirillum lipoferum Sp59b: structure and antigenic specificity.

Antigenic differences were revealed between the cell wall outer membrane lipopolysaccharides and the capsular high molecular weight bioglycans for a typical strain of the nitrogen-fixing rhizobacterium Azospirillum lipoferum Sp59b using antibodies prepared against the homologous lipopolysaccharide and lipopolysaccharide-protein complex. From the capsular lipopolysaccharide-protein and polysaccharide-lipid complexes of A. lipoferum Sp59b, polysaccharides were isolated and their structure was for the first time established in Azospirillum by monosaccharide analysis which included determination of the absolute configurations, methylation, O-deacetylation, and one- and two-dimensional NMR spectroscopy. The polysaccharides of the capsular complexes were shown to have identical structure of the branched tetrasaccharide repeating unit, which differs from the structure of the O-specific polysaccharide within the outer membrane lipopolysaccharide of this strain.

[Electrooptical properties of the microbial suspensions during a cell's interaction with the antibodies of a different specificity].

The electrooptical abilities of the microbial suspensions during a cells interaction with antibodies (ABs) of a different specificity have been studied on the example of the Azospirillum brasilense Sp245 cells and their interaction with the polyclonal monospecific and polyspecific antibodies. Measuring of the orientational spectra of the cells has been performed using the ELUS electrooptical analyzer. A discrete frequency set of an orienting electric field (740, 1000, 1450, 2000, and 2800 kHz) was used. It has been shown that an interaction of the polyspecific AB with the investigated cells redoubles the value of an electrooptical signal of the cells' suspension as compared with the monospecific antibodies. These findings can be used for a development a new method of microorganism detection.

[Ogilvie syndrome (colonic pseudo-obstruction). A case of the practice].

Ogilvie syndrome, or acute colonic pseudo-obstruction (ACPO), is a clinical disorder with the signs, symptoms, and radiographic appearance of an acute large bowel obstruction with no evidence of distal colonic obstruction. The other name of this disease is an acute non-toxic megacolon. The colon may become massively dilated; if not decompressed, the patient risks perforation, peritonitis, and death. The acute state has to be discerned immediatelly and treated adequately. The conservative tactics includes naso-gastric drainage, resustitation the homeostasis and stimulation the colonic peristalsis. The aggressive behavior includes an operative treatment or colonoscopic decompression. Some authors report for considerable rising in the frequency of the cases in postoperative period in some abdominal diseases. That's why they think that Ogilvie syndrome is a postoperative disease. We present a case of the practice-- an operated man with acute colonic pseudo-obstruction (ACPO) involving acute colonic ischaemia with necrosis.

[What is the value of ERCP in the era of MRCP?].

INTRODUCTION: The diagnostic approach in patients suspicious for gallstone disease is represented by two main methods--ERCP and MRCP. The magnetic resonance cholangio-pancreatography is safe and precise method of imaging diagnostics, while the endoscopy combines both good diagnostic and therapeutic possibilities. MATERIALS AND METHODS: 223 patients were enrolled, 68 of theme were with diagnosed cholestasis and endoscopic sphincterotomy, which was therapeutic in 53 cases. In all patients this condition has been diagnosed using MRCP--in 51 cases choledocholithiasis was diagnosed; 11 were with tumor obstruction; in 6 cases no mechanical cause was found. ERCP was performed on 62 patients with following therapeutical sphincterotomy. RESULTS: All 223 with performed cholecystectomy were with rate of conversion of 3% and hospital stay--3 days. There were no cases of pancreatitis after the sphincterotomy or hemorrhages requiring hemotransfusion. CONCLUSION: Algorithm including MRCP with performing endoscopic sphincterotomy is safe and effective in the diagnostic and treatment of choledocholithiasis. MRCP can be applied in addition to ERCP and IOC.

Intraoperative sentinel lymph node mapping in patients with colorectal cancer.

BACKGROUND/AIMS: In about 1/3 of the patients with colorectal cancer without metastases which have been radically operated recurrences are observed and these patients die from cancer. This requires improvement of the surgical methods radicality as well as a more accurate determination of the indications for adjuvant chemotherapy administration. The introduction of a method for evaluating the degree of the metastases in colorectal cancer would highlight these issues. To this purpose we apply the method of sentinel mapping. METHODOLOGY: For a period of one year we performed intraoperative sentinel mapping on 103 patients who had been operated for colon or rectal cancer. We used the dying method with Patent Blue V. An algorithm was worked out for sentinel mapping in colorectal cancer. RESULTS: We achieved 100% performance success and 97% sensitivity. We increased the volume of the surgical intervention in 100% of the patients and elevated the clinical stage of 20% of the patients in Ist and IInd stage by means of ultrastaging with immunohistochemistry. CONCLUSIONS: We conclude that sentinel lymph nodes mapping in colorectal cancer is a diagnostic method which is convenient for the surgeons allowing them for an individualized approach toward each patient.

[Composition and immunochemical characteristics of exopolysaccharides from the rhizobacterium Paenibacillus polymyxa 1465].

Exopolysaccharides (EPS) synthesized by Paenibacillus polymyxa 1465 in the course of batch cultivation were proven to contain neutral and acidic fractions. EPS are heterogeneous polysaccharides, represented by a complex of macromolecules with molecular mass of 7 x 10(4) to 2 x 10(6) Da. The acidic component was shown to be predominant in EPS preparations isolated from bacteria cultivated on glucose, which corresponds to a higher viscosity of EPS water solutions. The exoglycans were shown to contain glucose, mannose, galactose, and uronic acids. Polyclonal rabbit antibodies against the isolated P. polymyxa 1465 EPS preparations were used in a comparative immunodiffusion analysis of a number of P. polymyxa strains.

[Degradation of hydrocarbons and their derivatives by a microbial association based on Canadian pondweed].

The degrading action of an aquatic plant-microbial association on the base of Canadian pondweed (Elodea canadensis) and its components (sterilized plant and two periphytonic strains, Pseudomonas fluorescens E1-2.1 and Brevundimonas diminuta E1-3.1) on crude oil, the water-soluble crude oil fraction, and individual test compounds (phenol, toluene, benzene, decalin, and naphthalene) was studied. It was found that the native association had a wider range and higher degree of degrading activity than individual species. Bacterial strains were significantly more active only towards naphthalene. The ability of the sterilized plant to degrade crude oil and phenol was no less than that of microorganisms and much more for toluene. Enzymatic activity towards the pollutants studied was found in E. canadensis exudates and buffer extracts of its cells.

[Electrooptical parameters of kanamycin-treated E. coli cell suspensions].

The effect of kanamycin on the electrophysical parameters of cell suspensions of Escherichia coli K-12 and pMMB33 was investigated. Incubation of the sensitive K-12 strain with kanamycin resulted in significant changes in the orientation spectra (OS) of the cell suspensions; these changes were not revealed in the case of the resistant pMMB33 strain. In the case of the sensitive K-12 strain incubated with different kanamycin concentrations, changes in the OS of the cell suspensions occurred within the 10-1000 kHz frequency range of the orienting electrical field. The most pronounced change in the electrooptical signal was observed at 10 microg/ml of kanamycin. Control experiments were carried out by standard plating on nutrient media. Thus, the OS changes of suspensions in the presence of antibiotics may be used as a test for microbial resistance to such antibiotics.