Toxic effects of lead in plants grown in brazilian soils.

Lead (Pb) in soils can be transferred to plants, animals, and even humans. The toxicity of Pb is worrisome and therefore environmental quality criteria, established by laws to support the management of contaminated sites, have been developed to prevent its deleterious effects in a wide range of soils, uses, and occupations. In Brazil, the CONAMA Resolution 420/2009 established that Brazilian states may define their prevention values (PV) for metals in soils. However, the established values should be well studied, since a wide variation of sensitivity of species exposed to Pb is reported and several have a high tolerance. We aimed to evaluate Pb toxicity to validate the suitability of the current Brazilian Pb-prevention value. A trial was carried with two plant species (sorghum and soybean) grown in two tropical soils (Typic Hapludox and Rhodic Acrudox), following ISO 11.269-2 protocols (ISO 2012). The tested soils were contaminated with Pb-acetate at the following concentrations: 0, 200, 400, 800, 1200, 1600, 2200, 2800, and 3200 mg kg-1 of dry soil. Differences regarding species sensitivity were observed and sorghum seemed to be less sensitive to Pb concentration in soils. Soil characteristics as higher clay and organic matter content were responsible for decreasing the overall availability of Pb for plants. Using data from this study and from the literature, we constructed a species sensitivity distribution curve and calculated the HC5 (hazardous concentration to 5% of variables evaluated). The HC5 was 132.5 mg kg-1, which suggests that the PV currently used in Brazil (72 mg kg-1) is sufficiently protective for Brazilian soils.

Evaluation of mercury phytoavailability in Oxisols.

Mercury is a metal which is potentially toxic for the environment. Many factors control its retention in the soil, such as cation exchange capacity, pH, clay content, organic matter, and redox potential. It is important to know the phytotoxic effects of soil Hg to prevent environmental contamination and its entry into the food chain. Several analytical methods are used to measure metal phytoavailability in soils, but none has been reported for Hg in Oxisols, the most common soil class in Brazil and a very important soil class throughout the tropics. The aim of this study was to select the chemical extractor that best correlated the Hg levels in plants and the Oxisols. The soils used were classified as Dystrophic Red-Yellow Oxisol (LVAd) and Dystroferric Red Oxisol (LVdf), which were collected in the 0-0.2-m soil layer. The species selected for cultivation were a monocotyledon, oat (Avena sativa L. cv. São Carlos) and a eudicotyledon, common bean (Phaseolus vulgaris L. cv. Madrepérola). Each test plot was composed of a 500 cm3 pot filled with soil samples contaminated with HgCl2. Treatments were arranged in a completely randomized design, with four replications. The experiment was conducted for 30 days. Mercury contents were separately extracted with the following extractors: USEPA 3051A, Mehlich-1, Mehlich-3, DTPA, and water. Mercury was determined by hydride generation atomic absorption spectroscopy. The extracted contents were correlated with the contents in the tissues of the plants' aerial part by the Pearson correlation. Although it is not considered a standard procedure to evaluate metal phytoavailable contents, the method that presented the best correlations between soil Hg and plant Hg was USEPA 3051A (r = 0.75*). As expected, the worst correlation was with water (r = 0.57* for common bean and r = 0,05ns for oat).

Severe acute renal failure in adults: place of care, incidence and outcomes.

BACKGROUND: Department of Health guidelines recommend specialist critical care facilities for patients with severe single-organ failure such as acute renal failure (ARF). Prospective studies examining incidence, causes and outcomes of ARF outside of intensive care settings are lacking. AIM: To determine the incidence, causes, place of care and outcomes of severe single-organ ARF. DESIGN: Prospective observational study. METHODS: For 6 weeks in June-July 2003, renal physicians were contacted daily, and ICUs on alternate days, to identify cases of severe single-organ ARF in the Greater Manchester area. All patients with serum creatinine >or=500 micromol/l and not requiring other organ support were included. Patients with end-stage renal disease were excluded. Survivors were followed up at 90 days and 1 year from admission. Two independent consultant nephrologists assessed each case using anonymized summaries. RESULTS: Eighty-five patients had multi-organ ARF and 28 had severe single-organ ARF (380 and 125 pmp/year, respectively). Of those with single-organ ARF, 10 (36%) had known pre-existing chronic kidney disease. Renal replacement therapy (RRT) was required in 15 (54%). Total bed occupancy on ICUs relating to single-organ ARF was 59 days (range per patient 1-21). At 90 days, 18 (64%) were alive, and 17 (94%) had independent renal function. At 1 year, 4/18 had died, none receiving RRT at the time of death. Survivors all had independent renal function. In 13 (46%) cases there was an unacceptable delay in patient transfer and in 7 (25%), delays in assessment or commencement of RRT may have adversely affected patient outcome. DISCUSSION: The incidence of ARF treated with RRT is rising. Delays in transfer to renal services may result in inappropriate ICU bed use, and may adversely affect patient outcomes. There are serious problems regarding the appropriate use of expensive and limited medical resources in the critical care area, and in providing safe and effective treatment of patients with ARF.

Cholesterol feeding following unilateral nephrectomy in the rat leads to glomerular hypertrophy.

Experimental glomerulosclerosis is associated with hyperlipidaemia and the deposition of lipid in glomeruli. Glomerulosclerosis is typically preceded by glomerular hypertrophy. To investigate a possible pathogenic role of lipids in glomerulosclerosis, glomerular structure and cellular composition were studied in rats fed either a control diet or one supplemented with 4% cholesterol and 1% cholic acid for 21 weeks following unilateral nephrectomy. On the cholesterol diet there were significant increases in glomerular cross-sectional area (13.11 +/- 0.39 x 10(3) vs. 11.13 +/- 0.44 x 10(3) mu 2, p less than 0.01) and mesangial area (1.81 +/- 0.07 x 10(3) vs. 1.50 +/- 0.08 x 10(3) mu 2, p less than 0.02). These changes were significantly correlated with proteinuria, which was significantly greater on the cholesterol diet (mean area under curve for duration of diet = 3.11 +/- 0.38 vs. 1.42 +/- 0.35 g, p less than 0.02). There was a significant increase in glomerular leukocytes on the cholesterol diet (4.10 +/- 0.44 vs 2.86 +/- 0.25 OX-1 positive cells/10(4) mu 2, p less than 0.05). Mesangial foam cells, derived from macrophages, were associated with adhesions to Bowman's capsule. These results demonstrate that hyperlipidaemia exacerbates the development of glomerular hypertrophy and that this may be mediated by factors released during the phagocytosis of lipoprotein deposits by macrophages.

The role of lipids in the pathogenesis of glomerulosclerosis in the rat following subtotal nephrectomy.

Similarities between atherosclerosis and glomerulosclerosis suggest that hyperlipidaemia may contribute to glomerular injury. Dietary supplementation with 4% cholesterol + 1% cholic acid was administered to rats 4 weeks after 1 1/3 nephrectomy and continued for 7 weeks. There was a significant increase in serum cholesterol (peak = 11.52 +/- 1.09 mmol l-1 vs. 4.73 +/- 0.31 on control diet, P less than 0.001) and triglyceride concentrations (peak = 2.31 +/- 0.27 mmol l-1 vs. 1.41 +/- 0.29, P less than 0.05) and a marked increase in beta-migrating lipoproteins. The severity of hypercholesterolaemia was significantly correlated with proteinuria (control diet: r = 0.600, cholesterol diet: r = 0.672, P less than 0.0001) as was hypertriglyceridaemia (control diet: r = 0.544, cholesterol diet: r = 0.678, P less than 0.0001). The percentage of glomeruli containing lipid deposits was increased from 21% to 60% (P less than 0.05). The kidney total cholesterol content was increased from 29.2 +/- 0.8 to 47.7 +/- 3.3 mumols g-1 dry weight (P less than 0.0001), with esterified cholesterol increasing from 7.5 +/- 0.4% to 14.5 +/- 2.1% of total (P less than 0.01). Serum cholesterol concentration was significantly correlated with both glomerular lipid deposition (rs = 0.7195, P less than 0.0001) and tissue total cholesterol content (rs = 0.6053, P less than 0.001). Lipid vacuolation was prominent in the paramesangium and within mesangial cells. Despite these changes hypertension, uraemia, proteinuria and glomerulosclerosis were not significantly increased on the cholesterol diet. Cholesterol deposition in the glomeruli occurs secondary to hyperlipidaemia in rats following subtotal nephrectomy but over 7 weeks no exacerbation of glomerulosclerosis is detectable.

Effect of cholesterol on the position of segmental lesions in unilaterally nephrectomized rats.

Different positions of segmental lesions within glomeruli may correspond to different pathogenetic mechanisms. The effect of a high cholesterol diet on the position of lesions had not previously been investigated. This was studied in rats following unilateral nephrectomy, as a change in position would suggest a different mechanism of damage. Thirty-two female WAG/ola rats had unilateral nephrectomy. Half the rats were given a diet supplemented with 4 per cent cholesterol and 1 per cent cholic acid. At death, six at 10 weeks after nephrectomy and the rest at 24 weeks, kidney sections were examined microscopically. There were significantly more segmental lesions in the cholesterol-fed rats than in the controls, and these lesions were almost entirely at the glomerular hilum in both groups. Significantly more glomeruli contained foamy cells in the cholesterol-fed group, both within lesions and away from them. These findings confirmed that in reduced renal mass, segmental lesions are mainly hilar. The diet increases the number of glomeruli affected by lesions, but these are still mainly hilar. Therefore one possibility is that hypercholesterolaemia worsens the hyperfiltration effect on glomeruli. The diet also produces foamy cells scattered throughout the glomeruli but these do not appear to develop into segmental lesions.

Perspectives in multiple myeloma: survival, prognostic factors and disease complications in a single centre between 1975 and 1988.

One hundred and forty-one patients with multiple myeloma, diagnosed at the City Hospital, Nottingham between January 1975 and October 1986, were followed until death or for at least two years in a retrospective study. Overall median survival was 25 months, with no significant improvement occurring during the study period; increasing age, ESR and serum creatinine concentration at diagnosis were independent predictors of shortened survival. Renal impairment developed in 56 per cent of patients but only 7 per cent died of renal failure. At least one episode of infection occurred in 55 per cent of patients, most commonly in the first month. There was a significant rise in the overall incidence of infection and in the proportion caused by Gram-negative bacteria during the study period. Raised serum urea and low haemoglobin concentrations at diagnosis were independent risk factors for subsequent infection. Infection was associated with 2.75-fold increased risk of death, independent of other risk factors. Prevention of infection is an important aim for improvements in the survival of patients in multiple myeloma.

Receptor-mediated endocytosis of low-density lipoprotein by cultured human glomerular cells.

Lipoproteins might be involved in the pathogenesis of glomerular damage. Uptake of low-density lipoprotein (LDL) by cultured human glomerular cells has been studied using LDL, labelled with the fluorescent probe 1,1'-dioctadecyl-3,3,3'3'-tetramethyl-indocarbocyanine perchlorate (diI). Cells have been characterised using phase-contrast microscopy, monoclonal antibodies and lectins. Differentiated glomerular epithelial cells, epithelial-like cells and mesangial cells all took up diI-LDL. Uptake was specific for LDL, of high affinity and inhibited by excess unlabelled LDL, heparin and preloading the cells with cholesterol. Binding of diI-LDL to the cell surface was restricted to discrete areas which were arranged in linear arrays on mesangial cells. Endocytosis of surface-bound diI-LDL occurred within 3 min and breakdown of internalised diI-LDL within 30 min. These results indicate that cultured human glomerular cells take up LDL by receptor-mediated endocytosis.

Anthropometry underestimates body protein depletion in haemodialysis patients.

The body composition of 62 haemodialysis patients (41 males) and 63 controls (30 males) was assessed using anthropometry and in vivo neutron activation analysis of body nitrogen. There was no significant difference between patients and controls in body mass index (BMI) and percentage body fat. Arm muscle circumference was significantly reduced in males. Lean body mass was strongly correlated with body nitrogen in controls (r = 0.951) but less so in patients (r = 0.876). The mean standardised body nitrogen index (NI) was reduced in male patients by 13% (95% confidence interval -9 to -17%) and in females by 4% (95% confidence interval +4 to -12%). Of the 16 patients with a NI below the control range, arm muscle circumference was below the control range in only 3 and BMI less than 18 kg/m2 in 2. NI was correlated negatively with the duration of renal replacement therapy, duration of haemodialysis, the number of previous failed transplants and the total dose of steroids received but not with current energy or protein intakes. Steroid dose was the only significant independent variable. Anthropometry underestimates body protein depletion in haemodialysis patients and the degree of protein loss is related to the cumulative dose of corticosteroids previously received.

Assessment of renal osteodystrophy in dialysis patients: use of bone alkaline phosphatase, bone mineral density and parathyroid ultrasound in comparison with bone histology.

Bone biopsies were studied in 73 patients to determine if a two-site radioimmunometric assay for serum bone alkaline phosphatase (BAP), total serum alkaline phosphatase (ALP), serum intact parathyroid hormone (iPTH), hand X-rays, regional bone mineral density (BMD) measurements and parathyroid enlargement detected by ultrasonography could accurately predict renal osteodystrophy. In the patients studied 57 had hyperparathyroid bone disease, 4 mixed renal osteodystrophy, 3 adynamic bone disease, 1 osteomalacia and 8 normal histology. Serum BAP, ALP and iPTH correlated positively with mineral apposition rate, osteoblastic, osteoid and eroded surface. In the diagnosis of hyperparathyroid bone disease serum iPTH was the most sensitive investigation, detecting 81% of patients at a level > 100 pg/ml but with a specificity of only 66%. Serum BAP was more sensitive, 70% at a level of > 10 ng/ml, than serum total ALP, 30% at a level of 300 IU/l, with similar specificities, 92 and 100%, respectively. Ultrasound detection of an enlarged parathyroid gland had a sensitivity of 64% and a specificity of 100% for the diagnosis of hyperparathyroid bone disease. Hand X-rays had a poor sensitivity, 47%, but a high specificity, 92%, for the detection of hyperparathyroid bone disease. The majority of patients had regional BMD values within the normal reference range and this test was of poor discriminatory value. The non-invasive markers were unable to distinguish between patients with low turnover, mild hyperparathyroidism and patients with normal histology. In conclusion the measurement of serum iPTH is a useful screening tool for the detection of hyperparathyroid bone disease which can be confirmed by the finding of a raised serum BAP or parathyroid enlargement. For definitive diagnosis, however, the gold standard remains bone biopsy and at present one cannot recommend any non-invasive method as an adequate substitute.

Assessment of ultrasound guided percutaneous ethanol injection and parathyroidectomy in patients with tertiary hyperparathyroidism.

BACKGROUND: Tertiary hyperparathyroidism continues to cause significant morbidity in patients with chronic renal failure. This is frequently resistant to medical management and may ultimately require a surgical parathyroidectomy. Recent studies have reported upon the technique of percutaneous ethanol ablation for both primary and tertiary hyperparathyroidism. In this study we report on a 5 year experience using ethanol injection and compare the results with surgical parathyroidectomy. METHODS: A prospective study in 39 patients with tertiary hyperparathyroidism, 25 were dialysis dependent and 14 had a functioning renal allograft. Twenty-two patients underwent percutaneous fine needle ethanol injection (PFNEI) and 17 underwent surgical parathyroidectomy. RESULTS: A > 30% reduction in intact parathyroid hormone (iPTH) was achieved in 11 of 22 patients undergoing PFNEI after a mean of 1.8 +/- 1.4 injections per gland. In four patients, symptomatic hyperparathyroidism recurred and they required further PFNEI or surgical parathyroidectomy at 17, 28, 46, and 48 months later. There was no significant reduction in iPTH in 11 patients following PFNEI after a mean of 2.5 +/- 1.3 injections per gland. They all required a subsequent surgical parathyroidectomy for symptomatic hyperparathyroidism. Four patients developed a laryngeal nerve palsy following PFNEI, two of which were permanent. Seventeen patients underwent successful surgical parathyroidectomy as a primary procedure. CONCLUSION: Whilst PFNEI is successful in primary hyperparathyroidism, when typically only one adenoma is present, the effectiveness of PFNEI is unpredictable and the long term results are poor compared with those of surgical parathyroidectomy in tertiary hyperparathyroidism. The procedure is not without complications and makes subsequent surgery more difficult. Therefore it can only be recommended for patients with a known single parathyroid gland such as patients in whom hyperparathyroidism has recurred following a previous surgical subtotal parathyroidectomy and who are unsuitable for further surgery.