Aura Ramos

Cultivo de Brachiaria brizantha Stapf. cv. Marandu em solução nutritiva com omissões de macronutrientes

In a greenhouse experiment Brachiaria brizantha Stapf, cv. Marandu was grown in a nutrient solution. The treatments were a complete nutrient solution, nutrient solutions with the omissions of each macronutrient (N, P, K, Ca, Mg and S) and a control (with the omission of all macronutrients). Plants were harvested 50 days after transplanting. Dry matter yield, tiller number and plant height were recorded, and nutrient concentrations in shoot and root were determined. Omissions of N and P were the most limiting for plant growth, whereas K and Ca did not affect grass growth and tillering. Mg and S omissions resulted in significant decreases in the plant parameters. Great decreases in plant nutrient concentrations were verified in the treatments with nutrient omissions in solution. Visual symptoms of deficiencies were observed for each nutrient omission treatment, with those of N and P being the first and that of Ca being the latest shown by the plants. Studies on forms and sources of nutrients for nutrient solution to be used with this grass are suggested.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry-based profiling as a step forward in the characterization of peritoneal dialysis effluent

The aim of this study was to differentiate patients with glomerulonephritis and diabetic nephropathy using (i) peritoneal dialysate effluent, (ii) matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and (iii) bioinformatics tools. Profiles of peritoneal dialysate effluent were obtained using (a) sample preparation consisting of protein concentration through centrifugal concentrators and chemical-assisted protein depletion using DL-dithiothreitol, and (b) MALDI-TOF MS. A free open-source bioinformatics tool, Mass-UP, was used to classify such profiles using principal component analysis and hierarchical clustering. The methodology proposed here allows for classifying two different groups of patients with kidney failure, one with chronic glomerulonephritis and other with diabetic nephropathy.

Classifying patients in peritoneal dialysis by mass spectrometry-based profiling.

Protein equalization with dithiothreitol, protein depletion with acetonitrile and the entire proteome were assessed in conjunction with matrix assisted laser desorption ionization time of flight mass spectrometry-based profiling for a fast and effective classification of patients with renal insufficiency. Two case groups were recruited as proof of concept, patients with chronic glomerulonephritis and diabetic nephropathy. Two key tools were used to develop this approach: protein concentration with centrifugal concentrator tubes with 10 KDa cut-off membranes and chemical assisted protein equalization with dithiothreitol or chemical assisted protein depletion with acetonitrile. In-house developed software was used to apply principal component analysis and hierarchical clustering to the profiles obtained. The results suggest that chemical assisted protein equalization with dithiothreitol is a methodology more robust than the other two ones, as the patients were well grouped by principal component analysis or by hierarchical clustering.

Catheter-Related Bacteremia in Hemodialysis: Which Preventive Measures to Take?

Background: The use of tunneled hemodialysis catheters as definitive vascular access is becoming increasingly more widespread, reaching 25% of all dialysis patients in some countries. The rate of infectious morbidity and mortality is much higher when catheters are used than when patients are dialyzed through grafts or native fistulas, and it is generally agreed that implementing appropriate preventive measures would do more to lower its incidence. Methods: A prospective, randomized, open-label, long-term follow-up clinical trial was conducted to compare the efficacy of dressing the exit site with antibiotic ointment (AO) versus catheter antimicrobial locking (AL) in preventing catheter-related bacteremia (CRB), both associated with strict standard precautions and appropriate catheter care. A total of 141 tunneled catheters, newly implanted in 116 consecutive patients, were followed during a 2-year period. Patients were randomly distributed into one of three arms, with group A receiving AO prophylaxis, group B treated with a heparin + gentamicin (5.2 mg/ml) lock (AL) and group C receiving both AO and AL prophylaxis. Results: Group A had a significantly lower infection-free time survival curve (p < 0.02, Kaplan-Meier) with a catheter survival of 103.9 days and a significantly higher number of CRB (9 episodes, p < 0.02, χ2). Group B had 130.7 mean infection-free days and 1 episode of CRB. Group C had 127.3 mean infection-free days and 5 episodes of CRB. No toxicity or other adverse events were observed during this 2-year period, and the efficacy of the preventive measures remained stable throughout. Conclusion: Antimicrobial lock is superior to AO as a CRB preventive measure. The use of lock and ointment in the same catheter was not associated with additive effects.

Successful Treatment of Strongyloides stercoralis Hyperinfection in a Kidney Transplant Recipient: Case Report

Strongyloides stercoralis (SS) can cause hyperinfection and disseminated infection in immunosuppressed individuals, with risk of mortality. We report the case of a cadaveric kidney transplant recipient who developed gastrointestinal symptoms and eosinophilia, approximately 3 months after transplantation. Stool examination and esophagogastroduodenoscopy with biopsies were positive for SS larvae. The patient was started on oral ivermectin and immunosuppression was reduced, but still the clinical picture got worse with metabolic ileus and respiratory symptoms, with the need for administration of subcutaneous ivermectin and combined therapy with albendazol. The patient survived and graft function was preserved. The patient was unlikely to be the source of infection. We also present a review of cases of SS infection in kidney transplant recipients.

Late-Onset Post-transplantation Central Nervous System Lymphoproliferative Disorder: Case Report

Post-transplantation lymphoproliferative disorder (PTLD) is a heterogeneous group of conditions that complicate organ transplantation and are due to immunosuppression. Central nervous system (CNS)-PTLD is rare but its incidence is increasing. It often occurs late and is associated with kidney transplantation and Epstein-Barr virus (EBV) infection. Outcomes are poor. We present the case of a 77-year-old white male who received a cadaveric kidney transplant in 2003. Maintenance immunosuppression consisted of mycofenolate mofetil (MMF), cyclosporine, and prednisolone. In 2017, while admitted for other cause, he presented with de novo epileptic seizures. Because the patient had a pacemaker, magnetic resonance imaging (MRI) could not be performed. The final diagnosis of CNS-PTLD was known through brain biopsy, after a suitable image was obtained with contrasted brain computed tomography (CT). EBV was positive in brain biopsy, cefalospinal fluid, and blood. Treatment was attempted with reduction of immunosuppression. Cyclosporine was switched to sirolimus. The patient died before administration of rituximab. The patients performance status was poor. There must be awareness for neurological symptoms after kidney transplantation to timely diagnose CNS-PTLD. Contrasted brain CT may be useful to obtain a biopsy specimen in cases where MRI is impossible to use.