[Biofilm formation by Pseudomonas aeruginosa strains of Ukrainian collection of microorganisms].

The biofilm formation of three P. aeruginosa collection strains, isolated from human body, was investigated in stationary system on glass. It was shown, that biofilm formation of these microorganisms has three stages: initial formation, the further partial degradation and repeated accumulation. The intensity of biofilm formation correlates with survival rate of microorganisms in its structure that may be estimated by means of the "washout" method. The strain differences are typical of P. aeruginosa biofilm formation and determine further regularities of its development.

[Optimization of conditions of Pseudomonas aeruginosa bacteriocin induction].

Influence of cultivation conditions on activity of bacteriocins produced by Pseudomonas aeruginosa YKM B-333 has been investigated. It was shown, that the induction of bacteriocins with maximum activity values occurs on LB medium at 28 degrees C after addition of 100 microg/ml of nalidixic acid in a late logarithmic growth phase. Using the proposed methods for induction optimization permits to improve activity of P. aeruginosa YKM B-333 bacteriocins 256 times and to reach the index of 6.5 million AU/ml.

[Screening of producers of bacteriocin-like substances active against Pseudomonas aeruginosa].

The strains (n = 94) of 16 Pseudomonas species have been screened for producers of substances active against Pseudomonas aeruginosa. Investigated cultures were divided into two groups. The majority of Pseudomonas species have been included in the first group. These species were able to produce substances with low and medium activity spectrum. In the first group P. mendocina, P. fragi and P. taetrolens lysates were the most active and influenced 30-50% of indicator cultures. Only P. aeruginosa strains belong to the second group. The microorganisms of this group were able to produce substances with considerably higher activity spectrum. Among all investigated pseudomonades four P. aeruginosa strain lysates possessed the highest activity and were active against more than 75% of used cultures. It was shown that the main active killer components of these lysates belonged to low-weight pyocins.

[Characteristic, properties, prospect of application of bacteriocins].

Literary data and own research results dedicated to bacteriocin investigations have been analysed. Bacteriocins as one of the most widespread factors of bacterial antagonism, which are distinguished by the majority of microorganisms and characterized by bactericidal action in respect of representatives of phylogenetically related species have been considered. Allowing for their high lytic activity and narrow action specificity, the prospects for the use of the bacteriocins as possible alternative antibacterial remedies are examined. The basic approaches to bacteriocin classification, their variety, structure, killer properties and mechanisms of lytic action are presented. The perspective trends of the use and possible significance of these antibacterial substances in medicine are indicated.

[Characteristics of lysogenic induction of bacteriocins in thymine mutants of Erwinia carotovora].

Peculiarities of lisogenic induction of bacteriocins in thymine-dependent mutants of Erwinia carotovora subsp. carotovora have been studied. It was shown for the first time that availability of carotovoricins of two (and above) types characterized the defect polylysogeny of strains of different geographic origin. Use of various methods of induction of Thy--mutants or inducing agents of different nature leads to a selective accumulation of carotovoricins of certain types in the cell lysates. Results of the conducted investigations create preconditions for estimating an ecologic part of the defect lysogeny and bacteriocynogenicity for the important phytopathogenic bacterium E. carotovora.

A comparison of nocturnal penile tumescence and penile response to erotic stimulation during waking states in comprehensively diagnosed groups of males experiencing erectile difficulties.

The erectile responses of 13 nondysfunctional males and 48 dysfunctional males were compared during Nocturnal Penile Tumescence (NPT) and during exposure to erotic videotapes. The results showed distinct patterns of NPT and daytime responding that could differentiate the various subgroups: those displaying (i) no dysfunction; (ii) vasculogenic erectile dysfunction; (iii) high risk for erectile dysfunction (organic and psychogenic); (iv) psychogenic dysfunction; reactive to erotica; and (v) psychogenic dysfunction; nonreactive to erotica. Subjects participating in this study underwent a comprehensive medical and psychological screening to place them in each subgroup. The penile circumference response to erotic stimuli used in conjunction with NPT response appeared useful in differentiating subgroups of erectile dysfunction and suggested the need for further diagnostic refinement in this area. The majority of vasculogenic dysfunctional subjects experienced greater erection responses during exposure to erotic stimulation than during NPT; several of these subjects achieved almost full erections in waking states but were practically flaccid at night. The discussion covers diagnostic and therapeutic implications.

Cavernosography in conjunction with artificial erection for evaluation of venous leakage in impotent men.

Twenty men with incomplete penile erection or inability to maintain an erection were evaluated to determine if venous leakage was a cause. Cavernosography was performed in conjunction with artificial erection induced by infusion of saline into the corpus cavernosa. Thirteen patients requiring higher than normal rates of saline infusion to achieve or maintain erection showed filling of superficial veins in the flaccid state as well as during erection. In five of the seven patients with normal saline requirements there was no filling of superficial veins, and two showed filling in the flaccid state only. Of the thirteen patients whose conditions were diagnosed as venous leakage, seven underwent surgical ligation of superficial veins and deep penile vein arterialization by a saphenous vein bypass graft between the superficial femoral artery and deep penile vein. All these patients had reduced saline requirements postoperatively. When cavernosography is performed in the flaccid state only, filling of superficial veins can occur normally; therefore, these studies should be performed with artificial erection.

Deep-penile-vein arterialization for arterial and venous impotence.

Eleven impotent men underwent deep-penile-vein arterialization after preoperative assessment by a multidisciplinary team. Penile Doppler pressures, testosterone levels, and nocturnal penile tumescence were used to establish a vasculogenic etiology. Cavernosography, artificial erection by saline infusion, and selective hypogastric arteriography were obtained to delineate whether arterial, venous, or mixed (arterial/venous) factors predominated. Penile revascularization consisted of femoral artery to deep-penile-vein saphenous bypass, with ligation of superficial veins at the base of the penis in patients with venous leakage. Cumulative graft patency was 91% up to 20 months. There were no deaths. The average preoperative flow requirement of values greater than 250 mL/min was reduced to 59 mL/min postoperatively. Follow-up results of nocturnal penile tumescence were excellent in four of four patients with venous (venous leakage), two of three patients with arterial, and one of four patients with mixed factors. Deep-penile-vein arterialization appears to be beneficial for impotence secondary to venous leakage, with inconsistent results for arterial and mixed factors.

Transfemoral placement of intraluminal polyurethane prosthesis for abdominal aortic aneurysm.

Because of the significant mortality associated with the conventional surgical approach to abdominal aortic aneurysms (AAA) in the high risk patients and in those with ruptured aneurysms, we have developed a new approach to this problem, intraluminal aneurysm exclusion. This was achieved by an intraluminal prosthesis which approximated the diameter of the aorta above and below the aneurysm and is inserted through the femoral artery. The prosthesis consisted of biomedical grade elastomeric polyurethane with a NITINOL and/or stainless steel frame and was designed in such a configuration that it could be compressed inside a 15 F catheter and then regain its original shape after being discharged inside the aorta. The polyurethane prosthesis tolerated static pressures in excess of 300 Torr. Aneurysmal aortas were created in three adult sheep using large knitted Dacron pathches (6 X 9 cm) sewn onto a longitudinal aortotomy. After 4-6 weeks, an intraluminal prosthesis was passed transfemorally to the location of the aortic aneurysm. Following satisfactory placement and expansion of the prosthesis, a laceration was produced in the aneurysmal wall. No bleeding developed, which confirmed the integrity of the prosthesis in excluding the aneurysm from the aorta proper. Pulsation in the iliac arteries indicated the presence of aortic blood flow through the prosthesis. Autopsy examination demonstrated directly that the prosthesis was open and that its two ends were fixed in the aorta above and below the aneurysm. The study has demonstrated that intraluminal AAA exclusion could be achieved with an intraluminal polyurethane prosthesis inserted through the femoral artery.

In situ femoropopliteal and infrapopliteal bypass. Two-year experience.

We describe 83 in situ femoropopliteal and infrapopliteal artery bypass grafts. The in situ technique involved the valve incision method using scissors, the valvulotome (Leather), and a modified valve cutter (Hall). Arteriovenous fistulae were detected intraoperatively by angiography and/or the Doppler method and ligated. The operative indications were rest pain, ulcer, and gangrene in 88% of cases, and claudication in 7.2%. The mean preoperative ankle pressure was 61.3 mm Hg and the ankle-brachial index was 0.43. The mean postoperative ankle pressure was 125.3 mm Hg and the ankle-brachial index was 0.97. The vein utilization rate was 96%. One-year patency for popliteal anastomoses was 85.7%, for peroneal anastomoses it was 100%, and for infrapopliteal anastomoses it was 89.6%. The data suggest that the practicing vascular surgeon can adopt the in situ technique and can expect high graft patency rates even in limb salvage situations with poor distal outflow.

Relationship between vasa vasorum and blood flow to vein bypass endothelial morphology.

In order to define the respective roles of the vasa vasorum blood supply and intraluminal arterial blood flow in maintaining the endothelial integrity of in situ vein bypasses, we have carried out two separate but interrelated experiments in a canine model. In vivo studies on eight dogs demonstrated that even in the absence of intraluminal blood flow the vasa vasorum maintained endothelial integrity and also showed that the endothelium was very sensitive to the loss of the vasa vasorum blood supply. In a second group of experiments on 14 in situ vein bypasses we studied the effect of division of the vasa vasorum immediately after arterialization of the bypass. This experiment showed that arterialization of the vein maintained endothelial integrity despite division of the vasa vasorum.

Use of isovolemic hemodilution in the management of arterial ischemia in patients with polycythemia.

The management of patients with both polycythemia and limb-threatening ischemia presents many difficulties because in this population, vascular surgical procedures carry a particularly high incidence of hemorrhagic and thromboembolic complications. We evaluated the use of acute isovolemic hemodilution in 12 polycythemic patients who required urgent surgery due to severe ischemia and threatened limb loss. Within 48 hours, blood was withdrawn in units of 500 ml and simultaneously replaced with 1,500 ml of lactated Ringer's solution until a hematocrit of 35 to 40 percent was achieved. After hemodilution, two patients had such a marked improvement that no further therapeutic measures were required immediately. Four patients showed definite improvement in pulmonary vascular resistance tracings and segmental Doppler pressures, but ischemia was not fully ameliorated. These patients together with the remaining six patients underwent vascular surgery within 1 to 14 days after hemodilution. A hematocrit of 32 to 40 percent was maintained during the perioperative period. All arterial reconstructions were successfully completed and there were no perioperative failures. No pulmonary emboli, myocardial infarctions, or deaths occurred in this period. These results indicate that in polycythemic patients, urgent vascular surgery can be performed more safely with the concomitant use of acute isovolemic hemodilution.

Magnesium and other electrolytes in bovine eyeballs immersed in sea water and other fluids.

Bovine eyeballs were immersed in fluids including sea water for variable intervals of time, and magnesium concentrations and those of other electrolytes were determined in the aqueous and vitreous humor. Magnesium values increased with time, but no final saturation was reached nor were the levels obtained as high as those previously reported. In human immersion fatalities, Mg++ increased comparably to the most closely stimulating experimental situation, that is, corneal exposure in an unstirred medium. At best, vitreous Mg++ appears to be an imperfect marker in estimating the length of immersion, and then only if the sample remains unhemolyzed and the total post-mortem interval is considered. Establishing or excluding the diagnosis of drowning solely by this technique seems unlikely because of ion diffusion into the eye fluids.