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Strains of Pseudomonas that produce antimicrobial metabolites and control soilborne plant diseases have often been isolated from soils defined as disease-suppressive, i.e., soils, in which specific plant pathogens are present, but plants show no or reduced disease symptoms. Moreover, it is assumed that pseudomonads producing antimicrobial compounds such as 2,4-diacetylphloroglucinol (DAPG) or phenazines (PHZ) contribute to the specific disease resistance of suppressive soils. However, pseudomonads producing antimicrobial metabolites are also present in soils that are conducive to disease. Currently, it is still unknown whether and to which extent the abundance of antimicrobials-producing pseudomonads is related to the general disease resistance of common agricultural soils. Moreover, virtually nothing is known about the conditions under which pseudomonads express antimicrobial genes in agricultural field soils. We present here results of the first side-by-side comparison of 10 representative Swiss agricultural soils with a cereal-oriented cropping history for (i) the resistance against two soilborne pathogens, (ii) the abundance of Pseudomonas bacteria harboring genes involved in the biosynthesis of the antimicrobials DAPG, PHZ, and pyrrolnitrin on roots of wheat, and (iii) the ability to support the expression of these genes on the roots. Our study revealed that the level of soil disease resistance strongly depends on the type of pathogen, e.g., soils that are highly resistant to Gaeumannomyces tritici often are highly susceptible to Pythium ultimum and vice versa. There was no significant correlation between the disease resistance of the soils, the abundance of Pseudomonas bacteria carrying DAPG, PHZ, and pyrrolnitrin biosynthetic genes, and the ability of the soils to support the expression of the antimicrobial genes. Correlation analyses indicated that certain soil factors such as silt, clay, and some macro- and micronutrients influence both the abundance and the expression of the antimicrobial genes. Taken together, the results of this study suggests that pseudomonads producing DAPG, PHZ, or pyrrolnitrin are present and abundant in Swiss agricultural soils and that the soils support the expression of the respective biosynthetic genes in these bacteria to various degrees. The precise role that these pseudomonads play in the general disease resistance of the investigated agricultural soils remains elusive.

There are several immunological and non-immunological factors related to renal graft deterioration, and histological lesions such as interstitial fibrosis and tubular atrophy overlap with those observed in aging kidneys. Consequently, it has been proposed that kidney transplant senescence could contribute to graft loss. The process of cell senescence displays characteristics such as an increased expression of specific aging suppressor genes, shortened telomeres, mitochondrial changes, increased expression of negative regulators of the cell cycle, and immunological senescence. Additionally, tubular frailty characterizes the aged kidney, making it more susceptible to ischemia, reperfusion, toxic injury, and consequently, to inflammation. Moreover, renal tissue injury predisposes the older graft not only to progressive deterioration due to glomerular hyperfiltration, but also triggers acute rejection due to increased immunogenicity. In conclusion, renal graft senescence is a complex process, and its better understanding will help the nephrologist in its management in order to achieve a longer graft survival.

Background: The Modification of Diet in Renal Disease (MDRD) equation is widely used to estimate glomerular filtration rate (eGFR) in kidney transplant (KT) patients. The novel Chronic Kidney Disease-Epidemiology Collaboration equation (CKD-EPI) could improve accuracy of GFR estimation. Our aim was to compare both equations for staging of CKD in KT patients., Methods: In a cohort of KT patients, correlation of eGFR according to MDRD and CKD-EPI with 24-hour creatinine clearance (24h-CrCl) was evaluated. Concordance between both equations for CKD staging was performed. MDRD was used for initial CKD staging. The mean difference of GFR between 24h-CrCl and each equation was calculated and Bland-Altman analysis applied., Results: A cohort of 463 KT patients were studied: 67% female, overall average age 46 ± 14 years, 41% living donor, mean time of transplantation 71 months (3-95), and mean serum creatinine 1.68 ± 1.03 mg/dL. For the whole cohort (all CKD stages), eGFR by CKD-EPI was 5.33 mL/min/1.73 m(2) higher than by MDRD (P < .01). For CKD stages 1, 2, and 3A, the mean eGFR differences (CKD-EPI - MDRD) were 13.98 ± 3.27, 8.2 ± 1.98, and 5.34 ± 1.32 mL/min/1,73 m(2), respectively. The percentage of patients with eGFR <60 mL/min/1.73 m(2) decreased from 63.8% according to MDRD to 53.9% with the use of CKD-EPI. In women and patients ≤65 years old, eGFR by CKD-EPI was 5.98 and 5.81 mL/min/1.73 m(2) higher, respectively, than by MDRD (P < .01)., Conclusions: The novel CKD-EPI reduces the number of patients with eGFR <60 mL/min/1.73 m(2) and consequently assigns lower CKD stages to our KT population., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Pseudomonas protegens is a biocontrol rhizobacterium with a plant-beneficial and an insect pathogenic lifestyle, but it is not understood how the organism switches between the two states. Here, we focus on understanding the function and possible evolution of a molecular sensor that enables P. protegens to detect the insect environment and produce a potent insecticidal toxin specifically during insect infection but not on roots. By using quantitative single cell microscopy and mutant analysis, we provide evidence that the sensor histidine kinase FitF is a key regulator of insecticidal toxin production. Our experimental data and bioinformatic analyses indicate that FitF shares a sensing domain with DctB, a histidine kinase regulating carbon uptake in Proteobacteria. This suggested that FitF has acquired its specificity through domain shuffling from a common ancestor. We constructed a chimeric DctB-FitF protein and showed that it is indeed functional in regulating toxin expression in P. protegens. The shuffling event and subsequent adaptive modifications of the recruited sensor domain were critical for the microorganism to express its potent insect toxin in the observed host-specific manner. Inhibition of the FitF sensor during root colonization could explain the mechanism by which P. protegens differentiates between the plant and insect host. Our study establishes FitF of P. protegens as a prime model for molecular evolution of sensor proteins and bacterial pathogenicity.

Aim: Furosemide test is a simple and useful test of renal physiology usually used for evaluating the capability of the collecting ducts to secrete potassium under the effect of this drug. Its behaviour pattern has already been established in healthy children, young, and old people, as well as in stage III-chronic kidney disease (III-CKD) patients. However, its behaviour has not been described in kidney transplant patients yet, which we explored in this study., Materials and Methods: Twenty young volunteers on a standard western diet (50 mmol of potassium/day) were studied: Ten were III-CKD and the rest were kidney transplant (KT) patients on FK. Before, while the test was being carried out, and 180 min after a single dose of intravenous furosemide (1 mg/kg), urine and blood samples were obtained, for creatinine and potassium levels. From these data, we calculated fractional excretion of potassium (FEK). Statistical analysis was performed applying Wilcoxon test., Results: There was a significant difference regarding pre-furosemide (basal) FE of potassium between the III-CKD and KT groups 16 ± 5 (III-CKD) versus 7 ± 5 (KT), p = 0.008. Regarding the post-furosemide, peak FEK was significantly lower in the KT group (15 ± 11 %) compared to the III-CKD ones (49.8 ± 9 %, p = 0.01). In both groups, the peak FEK post-furosemide was reached later (120 min) compared to the conventional test (30 min)., Conclusion: Furosemide test showed significantly lower basal and post-furosemide peak FEK values in KT patients on tacrolimus compared with stage III-chronic renal disease.

Unlabelled: Furosemide test is a simple and useful test of renal physiology used to evaluate the capability of the collecting ducts to secrete potassium under the effect of serum aldosterone. Its behaviour pattern has been established in children and young adults but not described in very old healthy people, which we explored in this study., Material and Methods: Twenty-six healthy volunteers on a standard Western diet (50 mmol of K/day) were studied: 20 of them were young (between 17 and 40 years old) and the rest were very old (between 75 and 85 years old). They suffered from no diseases and were not on any medication. Before, during the test and 180 min after a single dose of intravenous furosemide (1 mg/kg), urine and blood samples were obtained for creatinine and electrolytes levels. From these data we calculated fractional excretion (FE) of electrolytes; serum aldosterone was measured pre and post furosemide infusion. Statistical analysis was performed by applying Student's t-test., Results: There was no significant difference regarding pre-furosemide (basal) FE of potassium between the very old and young group. Post-furosemide average FE of potassium was significantly lower in the very old group (27.4 +/- 2%) compared with the young group (35.4 +/- 9%) (P = 0.04). Even though there was no significant difference in post-furosemide peak FE of potassium value, it was reached later in the very old (120 min) compared with the young (30 min). Serum aldosterone levels were significantly higher post furosemide in both groups: 18.3 +/- 12.2 ng/dl (pre) versus 32.5 +/- 18.6 ng/dl (post) in the young (P = 0.007) and 69.8 +/- 13.7 ng/dl (pre) versus 113.3 +/- 54.8 ng/dl (post) in the very old (P = 0.04). Furthermore, all serum aldosterone values (pre and post furosemide) were significantly higher in very old people compared with young people (P < 0.001). Basal fractional excretion of sodium and chloride were slightly higher in the very old group compared with the young group (P = 0.05). Average post-furosemide FE of sodium and chloride were slightly and significantly lower in the very old (P = 0.05 and P = 0.03), respectively. However, there was no significant difference in peak post-furosemide FE of sodium and chloride values, which were reached later in the very old (120 min) compared with the young (30 min)., Conclusion: Furosemide test showed a significantly lower average post-furosemide FE of potassium value, delayed post-furosemide peak FE of Na, K and Cl and a hormonal pattern of aldosterone resistance in very old people.

Objective: The immobility syndrome (IS) is a common condition in the elderly and consists of a reduction in the capacity to perform daily activities because of motor function deterioration. This syndrome leads to characteristic structural and physiological changes in the body, but renal physiology studies have not been conducted on this population. For this reason, we decided to study prospectively changes in renal function in these individuals., Material and Methods: We enrolled into this study 17 volunteers over 64 years of age, all of whom lived in the same nursing home. The patients were divided into two groups: nine healthy mobile persons and eight others who suffered from severe IS. Exclusion criteria were the presence of any disease or use of any drug that could induce water and electrolytes alteration. Blood and urine samples were drawn to measure sodium, potassium, creatinine, urea, calcium, phosphorus, magnesium, and uric acid in order to obtain their fractional excretion. Plasma osmolality and vasopressin were also measured. Total body water and lean body mass were obtained by bioelectrical impedance analysis. Statistical analysis was performed applying Student's t-test (P = 0.01) and Pearson's correlation test., Results: A significant difference in body water composition was found between the groups. Thus in the IS group plasma sodium level was slightly lower and total water content was significantly higher than in the mobile subjects: 140 +/- 5 vs. 143 +/- 1 mmol/l (P = 0.01); 61 +/- 8% vs. 50 +/- 10% (P < 0.001), respectively. Despite these differences, plasma osmolality and vasopressin values were within the normal range in both groups. However, there was a good positive correlation between these two variables in the mobile group only: R 0.9 (mobile) vs. R -0.2 (immobile). We found no significant difference in plasma creatinine or fractional excretion of sodium, potassium, calcium, phosphorus, magnesium, urea, and uric acid between the groups., Conclusion: Total body water content was significantly higher in the elderly who suffered from severe immobility syndrome than in healthy mobile elderly. In contrast with the mobile group, for which there was a good positive correlation between plasma osmolality and plasma vasopressin, for individuals with IS there was no correlation between plasma osmolality and plasma vasopressin.

Senescence and chronic kidney disease (CKD) reduce progressively glomerular filtration rate (GFR), which usually results in an increase in potassium renal secretion. To evaluate whether the transtubular potassium concentration gradient (TTKG) is more accurate parameter for evaluating the renal secretion of this cation than using fractional excretion of potassium as its urinary secretion marker, we studied 55 subjects, 43 of them were healthy elderly volunteers and 12 were CKD patients. Exclusion criteria were: abnormal plasma potassium level or presence of any disease or drug that could induce alteration of balance of this electrolyte levels. All the subjects were on a diet with a potassium content around 50 mmol/day. The curves, which demonstrate the relationship between creatinine clearance and TTKG and the grade of correlation between these two parameters were analyzed in both groups. We found that the transtubular potassium concentration gradient had a significant negative correlation with the creatinine clearance level in the healthy elderly group, while there was no correlation in the CKD group.

Hyperkalemia is an unusual complication in peritoneal dialysis patients, having a prevalence of around 0.8% among the continuous ambulatory peritoneal dialysis (CAPD) population. The main cause of hyperkalemia in this group is the release of potassium from sources such as gross haematomas and rhabdomyolysis. However, there is no previous report regarding hyperkalemia induced by intracellular potassium shift into the intravascular compartment secondary to drug-induced acute hepatitis in peritoneal dialysis. We present the following case report of a peritoneal dialysis patient, well dialyzed and on a low-potassium diet, who was admitted in our hospital with paralysis secondary to hyperkalemia (serum potassium: 7 mmol/l). Both disorders disappeared using continuous automated peritoneal dialysis (APD) until liver enzymes normalized. We concluded that acute hepatitis can be a cause of hyperkalemia in a properly nourished and well-dialyzed peritoneal dialysis patient.

Unlabelled: Transtubular potassium concentration gradient (TTKG) is an index of potassium secretory activity in the distal tubule. Since water reabsorption takes place in the distal tubule as well, urine potassium concentration is a less accurate index evaluating distal K+ secretion because the effect of water is not taken into account on urine potassium concentrations. Potassium secretion and water reabsorption are strongly related to age and renal function. As a consequence, TTKG would be altered in both elderly individuals, as well as in patients with chronic renal failure (CRF). The aim of this study was to assess and compare TTKG in these two groups., Patients & Methods: A total of 55 individuals were studied, 12 of them were patients with CRF and 43 healthy elderly subjects with normal renal function. Informed consent was obtained from all patients. Patients with diabetes mellitus, cardiac failure, cirrhosis, obstructive uropathy, hyperkalemia, hypokalemia, or taking any medication that could alter the potassium balance were excluded from the study. All subjects were on a diet containing 50 mmol of potassium intake daily (documented by a three-day dietary record). Plasma potassium, creatinine, urea, glucose and osmolality were measured in all as well. 24 h creatinine clearance (CrCl ) and TTKG were calculated. Statistical analysis was made using Student's t-test., Results: TTKG was significantly lower in the elderly group (4.2+/-1.9 vs 6.2+/-1.8 , P 0.005)Both groups had a significantly lower TTKG when compared to healthy young people (8+/-2). Plasma and urine potassium levels, as well as plasma osmolality were similar in the two groups. Only urine osmolality was lower in the CRF group (382+/-141 vs. 514+/-180, P=0.01), Conclusion: Both old age and renal impairment lead to a reduced TTKG in comparison with young healthy people. Furthermore, TTKG is significantly lower in elderly healthy subjects compared to patients with CRF.

Background: Calcific uremic arteriolopathy is a rare and serious disorder characterized by systemic medial calcification of the arteries and tissue ischemia. Most often it is found in patients with chronic renal failure on dialysis and in renal transplant recipients with secondary hyperparathyroidism., Methods: We report six patients with end-stage renal disease [five on hemodialysis (one with a nonfunctioning renal graft) and one on peritoneal dialysis] who developed painful livedo reticularis and skin necrosis of the limbs. All had secondary hyperparathyroidism and elevated calcium-phosphorus product. Our patients presented with the following clinical features: white race (six patients), hypoalbuminemia (three patients), diabetes (one patient), and obesity (four patients)., Results: Subtotal parathyroidectomy was performed in three cases. Despite this procedure, two patients died; one patient survived and his lesions healed. One patient was treated with aggressive wound care and hemodialysis (with low dialysate calcium concentration and Renagel phosphorus binders) and one patient received only local wound care, both with improvement of their lesions. In one case, no therapy was performed because the patient died immediately after diagnosis., Conclusions: The three patients who survived (Cases 4, 5 and 6) had distal lesions, normal serum albumin, and an early diagnosis. There was a relationship between the outcome of the patients and these factors, rather than the type of treatment received.