BIOFILM FORMING ACTIVITY OF NON-FERMENTING GRAM-NEGATIVE BACTERIA.

OBJECTIVE: The aim: To study the influence of chemical, physical factors on the biofilm forming activity of P. aeruginosa, A. baumannii. PATIENTS AND METHODS: Materials and methods: Biofilm forming activity of P. aeruginosa (10 isolates) and A. baumannii (10 isolates) was studied in nutrient media of different composition. There was used the method in 96-well crystalline violet staining plates with spectrophotometry (STAT FAX®4300, wavelength of 620 nm). RESULTS: Results: Results showed that in standard medium (trypto-soy broth), strains of P. aeruginosa (90%) and A. baumannii (60%) obtained high biofilm forming activity. A. baumannii formed biofilms even in sterile water. Biofilm forming activity of urease positive P. aeruginosa increased in the medium with 1.0% urea. Both Acinetbacteria and Pseudomonas intensively produced their biofilms in the presence of 5% serum or sub-bacteriostatic concentrations of levofloxacin in the media. High concentrations of sodium chloride inhibited their biofilm activity. CONCLUSION: Conclusions: Isolates of Acinetobacter and Pseudomonas obtain the protective biofilm-forming ability under such adverse environmental conditions as insufficient nutrients, high osmotic pressure, the presence of antibiotics but at high concentrations sodium chloride biofilm-formation is stimulated only in the first bacteria and suppressed in the second one.

Effect of reduced sympathetic hyperactivity on cardiovascular risk factors in kidney transplantation patients.

BACKGROUND: Hyperactivity of the sympathetic nervous system caused by chronic kidney disease has detrimental effects on hypertension and cardiovascular morbidity. Kidney transplantation does not ameliorate sympathetic nerve overactivity; however, bilateral nephrectomy eliminates it. The aim of the study was to evaluate the effect of bilateral nephrectomy on risk factors for cardiovascular morbidity and mortality in long-term follow-up. MATERIAL AND METHODS: We studied 24 kidney recipients aged 44 ± 13 years who had undergone native bilateral nephrectomy. The control group included 17 recipients with preserved native kidneys who were matched for age, gender, cause of end-stage renal disease, immunosuppressive treatment, and time after transplantation. The mean follow-up after transplantation was 103 months. We evaluated arterial blood pressure, pulse pressure, metabolic markers, allograft function, echocardiography, and cardiac morbidity in all patients throughout follow-up. RESULTS: Systolic and diastolic blood pressures, number of antihypertensive drugs, and pulse pressure (a marker of arterial stiffness), were significantly lower among the study versus the control group (P < .05). The left ventricular mass, left ventricular mass index, left ventricular posterior wall thickness, and interventricular septum thickness were also lower in the study than in the control group (P < .05). Cardiac morbidity, including ischemic heart disease, atrial fibrillation, heart failure and stroke, occurred in 4 (16%) study group and 6 (35%) control subjects. Metabolic disorders, namely, new onset diabetes after transplantation, hyperuricemia, and dyslipidemia, occurred with similar frequencies in both groups. Serum levels of creatinine and estimated glomerular filtration rates were comparable in both groups, remaining stable throughout the observation time. CONCLUSIONS: Reduction of sympathetic hyperactivity by nephrectomy improved blood pressure control as well as decreased arterial stiffness and left ventricular hypertrophy over long-term follow-up. These results support native renal denervation to prevent the harmful effects of sympathetic hyperactivity on the cardiovascular system of renal transplant recipients.

Increased mucosal matrix metalloproteinase-1, -2, -3 and -9 activity in patients with inflammatory bowel disease and the relation with Crohn's disease phenotype.

BACKGROUND AND OBJECTIVE: Matrix metalloproteinases are associated with matrix turnover in both physiological and pathological conditions. We postulate an association between aberrant matrix metalloproteinases proteolytic activity and the intestinal tissue destruction, seen in patients with Crohn's disease and/or ulcerative colitis. MATERIALS AND METHODS: Surgically resected inflamed and non-inflamed ileum and colon with/without extensive fibrosis from 122 Crohn's disease, 20 ulcerative colitis and 62 control patients were homogenized. Protein levels of matrix metalloproteinases and tissue inhibitor of metalloproteinases were measured by enzyme-linked immunosorbent assays (ELISA), while matrix metalloproteinases and myeloperoxidase activity were measured by specific activity assays. RESULTS: Expression of total levels of matrix metalloproteinases-1, -2, -3 and -9 relative to tissue inhibitor of metalloproteinases-1 and -2 was increased in inflamed inflammatory bowel disease compared to non-inflamed inflammatory bowel disease and control intestinal mucosa. Also, net matrix metalloproteinases-1, -2, -3 and -9 activity in inflamed inflammatory bowel disease was increased, with similar expression profiles in Crohn's disease and ulcerative colitis. Within inflamed inflammatory bowel disease, a close correlation of matrix metalloproteinases with myeloperoxidase was observed. The expression of matrix metalloproteinases and tissue inhibitor of metalloproteinases was similar in inflamed Crohn's disease tissue with or without extensive fibrosis and not related to fistulizing disease. CONCLUSIONS: We have shown increased net matrix metalloproteinases activity in intestinal inflammatory bowel disease tissue, likely to contribute to the tissue damage and remodelling seen in inflammatory bowel disease.

Effect of cortisol and ACTH on corticosteroid-suppressed peripheral blood natural killer cells from healthy volunteers and patients with Crohn's disease.

Recently, we have shown that administration of adrenocorticotropic hormone (ACTH) to corticosteroid-treated Crohn's disease (CD) patients increased the peripheral blood natural killer (NK) cell activity which was suppressed by the corticosteroids. To elucidate this observation we analysed the in vitro effect of budesonide, prednisolone, cortisol, and ACTH on NK cells of healthy volunteers and corticosteroid-treated CD patients. Incubation of peripheral blood mononuclear cells (PBMNC) from healthy volunteers during the cytotoxicity assay caused a dose-dependent inhibition of NK cell activity by the three corticosteroids, while ACTH had hardly any effect. Pre-incubation for 18 h with high and low inhibiting concentrations also showed a significant inhibiting effect on NK cell activity of the corticosteroids. The percentage of CD56+ NK cells tended to increase after pre-incubation with a high inhibiting concentration of budesonide, prednisolone, and cortisol. Incubation of budesonide- or prednisolone-suppressed PBMNC from healthy volunteers and CD patients, with ACTH and/or cortisol, to mimic the in vivo situation, did not restore the corticosteroid-induced suppression of NK cell activity. The increase of the budesonide- or prednisolone-suppressed NK cell activity after in vivo administration of ACTH to the CD patients is therefore probably not a direct effect of cortisol or ACTH. Presumably other factors like cytokines and/or neurohormones must be involved in the in vivo interaction between corticosteroids, ACTH, and NK cells.

c-Ha-ras oncogene transfection does not affect NK cell sensitivity of human colorectal carcinoma cell lines.

BACKGROUND, MATERIALS AND METHODS: To investigate whether a c-Ha-ras oncogene, pointmutated in codon 12, modulates NK sensitivity of human colorectal tumor cells, this oncogene was introduced in two colorectal carcinoma cell lines, i.e. CaCo2 and SW480. RESULTS: Although transfection with this oncogene increased the levels of c-Ha-ras mRNA (4- to 5-fold) and induced phenotypic and genotypic changes, respectively, in the CaCo2 and SW480 cell lines, the susceptibility to NK cell lysis was only marginally affected. However, CaCo2 and SW480 cell lines transfected with a plasmid containing the wild type of the c-Ha-ras gene were found to be more sensitive to NK cells. CONCLUSIONS: The present study suggests that the sensitivity of human colorectal carcinoma cells to NK cell activity in vitro depends only marginally on the expression of the c-Ha-ras oncogene.