Evaluation of Xanthomonas campestris survival in a soil microcosm system.

Xanthomonas campestris pv. campestris is a pathogen of cruciferous plants. We studied the survival of the wild type strain and mutant derivatives which are deficient in exopolysaccharide (EPS) or in extracellular protease synthesis in soil microcosms in order to test the hypothesis that, in this environment, adherence to soil particles and scavenging of nutrients are very important strategies for bacterial survival. In sterile soil microcosms, differences in survival were only observed between the EPS producer and its mutant. In non-sterile soil experiments, survival of Prt- mutant was similar to EPS- mutant, suggesting that both characteristics have a strong influence in survival in the presence of the natural bacterial community. Bacterial decrease represented by the slope of regression lines was higher in non-sterile soil microcosms due to the influence of biotic interactions.

Plasminogen: an important hemostatic parameter in septic patients.

BACKGROUND: Previously we observed in some but not all septic patients a low plasma concentration of plasminogen. OBJECTIVES: To investigate prospectively whether plasma levels of plasminogen or the ratio of plasminogen to alpha-2-antiplasmin have a prognostic value for survival from sepsis and to study the variation of other hemostatic parameters during septicemia. PATIENTS: The study population consisted of 45 consecutive patients with septicemia, 15 non-septic patients from the same intensive care unit and 30 healthy volunteers. MEASUREMENTS AND MAIN RESULTS: Plasminogen concentrations were significantly lower (p < 0.001) in plasma of septic patients (median 0,62 IU/ml range: 0.15-1,06) than in plasma of healthy controls (median 1.00 IU/ml, range: 0.75-1.10) or of non-septic intensive care patients (median 1.00 IU/ml, range: 0.82-1.08). Among the other parameters tested, plasminogen activator inhibitor (PAI-1) antigen concentration and PAI activity were similar in septic and non-septic intensive care patients, but higher than in healthy controls. Concentrations of elastase-alpha-1-protease inhibitor or of thrombin-antithrombin complexes were higher in septic patients than in non-septic intensive care patients or healthy controls. A degraded form of plasminogen of 38 kDa was detected by Western blot analysis in the plasma of septic patients, but not in plasma of non-septic intensive care patients or controls. Plasminogen alone or the ratio of plasminogen to antiplasmin were good markers for survival from septicemia. E.g. for plasminogen at a cut off of 0.65 IU/ml, sensitivity was 90.5% and specificity 66.7%, whereas for the ratio of plasminogen over antiplasmin at a cut off ratio of 0,65 IU/ml, sensitivity was 95.2% and specificity 70.8%. CONCLUSION: Plasminogen or the ratio of plasminogen to antiplasmin are sensitive markers for survival in patients with septicemia.

Protein restriction and progression of chronic renal failure.

The effect of protein restriction upon the rate of renal functional decline was studied in 7 patients with moderate chronic renal failure (CRF). The rate of progression of CRF was evaluated by the reciprocal of plasma creatinine concentration (1/Cr) in time method, every 1-3 months, during 12 months while on ad-libitum diet and 23-40 months thereafter while on protein restriction. While on ad-libitum diet, 4/7 patients showed a progressive disease and the other 3 showed a relatively stable evolution. Six months after protein restriction, patients with a previous progressive disease showed an amelioration in the decline in renal function, and those with stable CRF showed a worsening of the disease in two cases and an improvement in the other one. During the first six months on low protein diet, a transitory increase in plasma creatinine concentration was observed, being maximum at 2.7 months. Plasma urea concentration fell, after protein restriction, to values close to that predicted at the time of the prescription of the diet. Mean systolic and diastolic arterial blood pressure remained stable throughout the study and it was not necessary to change the pharmacological treatment. Our data show that protein restriction decreases the rate of progression of CRF in patients with previous progressive disease. This benefit may result from the suppression of compensatory hyperfiltration induced by low protein diet, as suggested by the increase in plasma creatinine concentration.

Protein restriction and progression of chronic renal failure.

The effect of protein restriction upon the rate of renal functional decline was studied in 7 patients with moderate chronic renal failure (CRF). The rate of progression of CRF was evaluated by the reciprocal of plasma creatinine concentration (1/Cr) in time method, every 1-3 months, during 12 months while on ad-libitum diet and 23-40 months thereafter while on protein restriction. While on ad-libitum diet, 4/7 patients showed a progressive disease and the other 3 showed a relatively stable evolution. Six months after protein restriction, patients with a previous progressive disease showed an amelioration in the decline in renal function, and those with stable CRF showed a worsening of the disease in two cases and an improvement in the other one. During the first six months on low protein diet, a transitory increase in plasma creatinine concentration was observed, being maximum at 2.7 months. Plasma urea concentration fell, after protein restriction, to values close to that predicted at the time of the prescription of the diet. Mean systolic and diastolic arterial blood pressure remained stable throughout the study and it was not necessary to change the pharmacological treatment. Our data show that protein restriction decreases the rate of progression of CRF in patients with previous progressive disease. This benefit may result from the suppression of compensatory hyperfiltration induced by low protein diet, as suggested by the increase in plasma creatinine concentration.

Protein restriction and progression of chronic renal failure.

The effect of protein restriction upon the rate of renal functional decline was studied in 7 patients with moderate chronic renal failure (CRF). The rate of progression of CRF was evaluated by the reciprocal of plasma creatinine concentration (1/Cr) in time method, every 1-3 months, during 12 months while on ad-libitum diet and 23-40 months thereafter while on protein restriction. While on ad-libitum diet, 4/7 patients showed a progressive disease and the other 3 showed a relatively stable evolution. Six months after protein restriction, patients with a previous progressive disease showed an amelioration in the decline in renal function, and those with stable CRF showed a worsening of the disease in two cases and an improvement in the other one. During the first six months on low protein diet, a transitory increase in plasma creatinine concentration was observed, being maximum at 2.7 months. Plasma urea concentration fell, after protein restriction, to values close to that predicted at the time of the prescription of the diet. Mean systolic and diastolic arterial blood pressure remained stable throughout the study and it was not necessary to change the pharmacological treatment. Our data show that protein restriction decreases the rate of progression of CRF in patients with previous progressive disease. This benefit may result from the suppression of compensatory hyperfiltration induced by low protein diet, as suggested by the increase in plasma creatinine concentration.