Comparing phosphorus mobilization strategies using Aspergillus niger for the mineral dissolution of three phosphate rocks.

Phosphorus deficiencies are limiting crop production in agricultural soils worldwide. Locally available sources of raw phosphate rock (PR) are being recognized for their potential role in soil fertility improvement. Phosphorus bioavailability is essential for the efficiency of PRs and can be increased by acid treatments. The utilization of organic acid producing micro-organisms, notably Aspergillus niger, presents a sustainable alternative to the use of strong inorganic acids, but acid production of A. niger strongly depends on the mineral content of the growth media. This study compared the phosphorus mobilization efficiency of two biological treatments, namely addition of acidic cell-free supernatants from A. niger cultivations to PRs and the direct cultivation of A. niger with PRs. The results show that addition of PR to cultivations leads to significant differences in the profile of organic acids produced by A. niger. Additions of PR, especially igneous rocks containing high amounts of iron and manganese, lead to reduced citric acid concentrations. In spite of these differences, phosphorus mobilization was similar between treatments, suggesting that the simpler direct cultivation method was not inferior. In addition to citric acid, it is suggested that oxalic acid contributes to PR solubilization in direct cultivations with A. niger, which would benefit farmers in developing countries where conventional fertilizers are not adequately accessible.

Management of end-stage renal disease in children.

OBJECTIVE: To review the medical literature on management of end-stage renal disease (ESRD) and its complications in the pediatric patient. DATA SOURCES AND STUDY SELECTION: MEDLINE searches (1970-1997) of the English-language literature. Clinical trials and reviews of drug therapy management were included, and bibliographies were reviewed for relevant articles. DATA SYNTHESIS: Principles of renal replacement therapy in children have been expanded to include maintenance of fluid and electrolyte balance and to manage the complications of ESRD in children. Types of renal replacement and their complications are reviewed. Complications of ESRD are reviewed with emphasis on drug therapy management of anemia of chronic renal failure, growth retardation, and hypertension. A discussion of the use of vitamins and supplements to maintain bone and mineral homeostasis is provided, and specific recommendations for vaccination of children with ESRD are given. CONCLUSIONS: Children with end-stage renal failure present a unique challenge to the pharmacist. Renal replacement therapy for children with ESRD involves some form of dialysis and an intensive medication regimen. Complications must be treated with appropriate drug therapy. Drug therapy must be monitored closely for dosage adjustment, clinical response, drug interactions, and toxicity. Patients and families must receive continuous education and follow-up to encourage compliance. The pharmacist must work closely with the healthcare team to optimize drug therapy and improve patient education and compliance.

Angiotensin-converting enzyme inhibition in nondiabetic progressive renal insufficiency: a controlled double-blind trial.

Angiotensin-converting enzyme inhibitors delay progression of renal disease in different animal models of nephropathy. We tested this treatment modality in 70 hypertensive patients with severe renal disease of various etiologies. We report a double-blind study of the effect of 5 mg enalapril once daily compared with placebo in patients with nondiabetic severe chronic renal impairment (plasma creatinine 2.8 to 6.8 mg/dL; mean creatinine clearance 15 mL/min/1.73 m2) followed for up to 2 years. Efficacy parameters were the slopes of 51Cr-EDTA clearance, reciprocal of plasma creatinine, creatinine clearance, and the effect on urinary protein excretion. Thirty-one patients completed 2 years of treatment (12 in the enalapril group and 19 in the placebo group). Two patients died from nonrenal causes (one patient each in the enalapril and placebo groups), 16 patients commenced dialysis (seven in the enalapril group and nine in the placebo group), and eight patients were discontinued due to adverse events (five in the enalapril group and three in the placebo group). Eleven patients were discontinued because they were noncompliant, uncooperative, or moved (nine in the enalapril group and two in the placebo group). Two enalapril-treated patients were dropped from the study due to protocol deviations. Importantly, the statistical approach in this study evaluated all patients, regardless of the duration of treatment. A mixed-effects linear model and intention to treat analysis, taking into account the number of observations per patient, indicated that enalapril significantly reduced the rate of deterioration of renal disease: glomerular filtration rate (P = 0.038), reciprocal of plasma creatinine (P = 0.017), or creatinine clearance (P = 0.031). The renal protective effects of enalapril were shown to be in addition to its antihypertensive effect when blood pressure was held constant. Proteinuria was reduced by enalapril (P = 0.007) and was slightly increased in the placebo-treated patients (P = 0.051). The difference between these two groups was highly significant (P = 0.002). In conclusion, enalapril retarded the progression of chronic renal failure, as assessed by changes in glomerular filtration rate, creatinine clearance, and 1/plasma creatinine, and reduced proteinuria in patients with nondiabetic severe chronic renal insufficiency.

The effect of treatment with prednisolone or cyclophosphamide-warfarin-dipyridamole combination on the outcome of patients with membranous nephropathy.

Between 1973 and 1986, 109 patients with membranous nephropathy have been evaluated with respect to clinical presentation, pathological features and factors determining prognosis. Secondary disease was present in 21, and a further 21 were lost or followed for less than 12 months. The remaining 67 with idiopathic membranous nephropathy were allotted to one of three groups. Group 0 (26 patients) received no active treatment, Group 1 (12 patients) a combination of cyclophosphamide, dipyridamole and warfarin, and Group 2 (21 patients) high dose alternate day prednisolone therapy. Eight patients received other treatment or presented with end stage renal disease. No significant difference in outcome could be detected between the groups. Remission rates were equivalent as were numbers of patients judged as having progressive disease. There was no statistical difference with respect to duration of nephrotic syndrome, plasma creatinine at the end of study and change in plasma creatinine. No demonstrable benefit was obtained in predicting the outcome of disease or response to treatment from conventional pathological grading of stages I to IV as approximately equal numbers of each stage fell into good and bad categories of outcome. Similarly unusual histological features such as mesangial proliferation and immunofluorescence for deposits other than IgG and C3 were not helpful. A different approach to treatment of idiopathic membranous nephropathy is strongly recommended.

Socioeconomic evaluation of a state-funded comprehensive hemophilia-care program.

To assess the effectiveness, cost, and socioeconomic gains associated with a comprehensive state-funded hemophilia program, we compared data from a three-year experience with such a program in Rhode Island with those from the preceding year. Self-treatment, integration of children into school, and achieving satisfying employment of adults are the main goals of the program. During the most recent year, 77 per cent of the patients with severe hemophilia in the state received total care through the Hemophilia Center. Twenty-eight of the 43 patients now treat themselves, the annual number of hospital days per patient has decreased from 12.6 to 3.5, and the number of visits to hospital facilities has fallen from 34 to 2.4, while the yearly cost of clotting factor per patient has remained about $7,000. Altogether, this has saved more than $10,000 each year for treatment, despite the cost of rehabilitative surgery. Numbers of days lost from school and work have decreased twofold and threefold, respectively. Best of all, comprehensive care has vastly improved the quality of life for patients with hemophilia in Rhode Island.