Search

Accounting for small-size tree biomass is critical to improve total stand biomass estimates of secondary tropical forests, and is essential to quantify their vital role in mitigating climate change. However, owing to the scarcity of equations available for small-size trees, their contribution to total biomass is unknown. The objective of this study was to generate allometric equations to estimate total biomass of 22 tree species ≤ 10 cm in diameter at breast height (DBH), in the Yucatan peninsula, Mexico, by using two methods. First, the additive approach involved the development of biomass equations by tree component (stem, branch and foliage) with simultaneous fit. In the tree-level approach, total tree biomass equations were fit for multi-species and wood density groups. Further, we compared the performance of total tree biomass equations that we generated with multi-species equations of previous studies. Data of total and by tree component biomass were fitted from eight non-linear models as a function of DBH, total height (H) and wood density (ρ). Results showed that two models, identified as model I and II, best fitted our data. Model I has the form AGB = β0 (ρ·DBH2·H)β1 + ε and model II: AGB = exp(-β0)(DBH2·H)β1 + ε, where AGB is biomass (kg). Both models explained between 53% and 95% of the total observed variance in biomass, by tree-structural component and total tree biomass. The variance of total tree biomass explained by fit models related to wood density group was 96%-97%. Compared foreign equations showed between 30% and 45% mean error in total biomass estimation compared to 0.05%-0.36% error showed by equations developed in this study. At the local level, the biomass contribution of small trees based on foreign models was between 24.38 and 29.51 Mg ha-1, and model I was 35.97 Mg ha-1. Thus, from 6.5 up to 11.59 Mg ha-1 could be excluded when using foreign equations, which account for about 21.8% of the total stand biomass. Local equations provided more accurate biomass estimates with the inclusion of ρ and H as predictors variables and proved to be better than foreign equations. Therefore, our equations are suitable to improve the accuracy estimates of carbon forest stocks in the secondary forests of the Yucatan peninsula.

Aims: To identify factors associated with cardiovascular (CV) disease in hemodialysis., Methods: Multicenter, prospective, 2-year, observational study in 2,310 incident patients (3,496 patient-years). Multivariate Cox models determined baseline characteristics associated with CV disease., Results: Main factors associated with CV deaths (6.3/100 patient-years) were: high Charlson score (hazard ratio (HR) 3.6; 95% confidence interval (CI) 1.7-7.5 for ≥9 vs. ≤4); low Karnofsky score (KS; HR 2.2; 95% CI 1.5-3.3 for KS ≤50 vs. >70); female gender (HR 1.4; 95% CI 1.1-1.9); catheter access (HR 1.4; 95% CI 1.0-1.9); low (<3.5 g/dl) albumin (HR 2.5; 95% CI 1.8-3.3); ferritin deficiency (HR 1.6; 95% CI 1.2-2.2 for <100 vs. ≥100-500 ng/ml) and low body mass index (BMI; HR 1.9; 95% CI 1.2-3.0 for <20 vs. 20-25). A BMI of ≥30 was a protective factor (HR 0.6; 95% CI 0.4-0.9)., Conclusions: There is a high CV risk, especially in older patients with high comorbidity, low BMI, low albumin or iron deficiency. Catheter access increases the CV death risk., (Copyright © 2011 S. Karger AG, Basel.)

Background: Although the association between low haemoglobin levels and mortality is well established in haemodialysis patients, data are conflicting regarding levels >12 g/dl. In addition, divergent results have been reported on the relation between erythropoiesis-stimulating agents (ESAs) and mortality., Methods: This was a multicentre, observational, prospective, 24-month study, which recruited Spanish incident haemodialysis patients (N = 2310). Univariate and multivariate time-dependent Cox regression models examined the longitudinal association of mortality with haemoglobin and ESA dose; adjustment was made for iron deficiency and other confounders., Results: After adjusting for age, functional status, body mass index, albumin levels, catheter as vascular access, previous history of cardiovascular disease, neoplasia, and ESA dose, mortality decreased with increasing haemoglobin. Adjusted hazard ratios relative to the reference category (11-12 g/dl) and 95% confidence intervals were: 1.36 (1.01-1.86) for 13 g/dl. Independent of haemoglobin, patients on sustained ESA doses of 1-4000 IU/week and 8001-16 000 IU/week had better survival than non-treated (reference) patients, with adjusted hazard ratios of 0.61 (0.41-0.90) and 0.68 (0.49-0.94), respectively. No significant difference was found for doses of 4001-8000 IU/week or >16,000 IU/week, adjusted hazard ratios of 0.87 (0.63-1.20) and 0.89 (0.63-1.28), respectively., Conclusions: Higher haemoglobin levels are associated with lower mortality in Spanish incident haemodialysis patients, regardless of ESA dose, comorbidity, vascular access or malnutrition. No increase in mortality occurs for high ESA doses, independent of haemoglobin levels.

Background: The ANSWER study aims to identify risk factors leading to increased cardiovascular morbidity and mortality in a Spanish incident haemodialysis population. This paper summarizes the baseline characteristics of this population., Methods: A prospective, observational, one-cohort study, including all consecutive incident haemodialysis patients from 147 Spanish nephrology services, was conducted. Patients were enrolled between October 2003 and September 2004. Sociodemographic, clinical, laboratory and health care characteristics were collected., Results: Baseline characteristics are described for 2341 incident haemodialysis patients [mean (SD) age 65.2 (14.5) years, 63% males]. The main cause of renal failure was diabetic nephropathy (26%). The majority of patients (57%) had a Karnofsky score of 80-100 and 27% were followed up by a nephrologist for 500 ng/ml, 41% and saturated transferrin <20 or >40%, 50%) despite previous treatment with erythropoiesis-stimulating agents in 41% of cases., Conclusions: There is excessive use of temporary catheters and a high prevalence of uraemia-related cardiovascular risk factors among incident haemodialysis patients in Spain. The poor control of hypertension, anaemia, malnutrition and mineral metabolism and late referral to a nephrologist indicate the need for improving the therapeutic management of patients before the onset of haemodialysis.

Background: The study was conducted in order to describe possible intraglomerular haemodynamic changes inducing proteinuria after 14 patients with chronic allograft dysfunction were converted from calcineurin inhibitors (CIs) to sirolimus without changing concomitant immunosuppression or antihypertensive treatment., Methods: Creatinine, glomerular filtration rate (GFR), proteinuria, renal functional reserve (RFR) and effective renal plasma flow (ERPF) were determined before and 8 months after conversion. Intraglomerular pressure (P(G)), afferent arteriolar resistance (AAR) and efferent arteriolar resistance (EAR) were calculated using Gomez's formula., Results: Creatinine (1.97 vs 2.075 mg/dl; P = 0.270) and GFR (40 vs 43 ml/min; P = 0.505) remained unchanged, proteinuria increased (338 vs 1146 mg/24 h; P = 0.006), RFR decreased (34.84 vs 13.47%; P = 0.019), ERPF (248 vs 310.6 ml/min; P = 0.0625) and P(G) (42.72 vs 46.17 mmHg; P = 0.0625) tendentially increased and AAR tendentially decreased (14.12 vs 10.28 dyne/s/cm(5); P = 0.0625)., Conclusion: After conversion, P(G) shows a tendency to increase and RFR decreases significantly-characteristics of hyperfiltration, which could possibly partially explain the increase of proteinuria. Therefore, the application of angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers seems promising. To avoid hyperfiltration, conversion should be performed early when renal insufficiency is still moderate.

Objective: To evaluate the level of compliance with the 2002 consensus document (Spanish Society of Nephrology) on guidelines for the detection, prevention and treatment of diabetic nephropathy in Catalonia., Subjects and Methods: Multicenter (23 hospitals), observational, cross-sectional, descriptive study conducted in 413 diabetic patients (61.7% men, 38.3% women) with a median age of 66.2 +/-11.5 years (26-93 years). The ANOVA test (post-hoc analysis; p value< 0.05) was used to study the relationships between the stages of diabetic nephropathyand different variables., Results: 90.3% of the patients had type 2 DM. The following anthropometric parameters were observed: BMI 29.8 +/- 5 kg/m2 (BMI > 30 kg/m2: 48.7%) and waist circumference 104.1 +/- 14 cm (48.6% men > 102 cm and 78.9% women > 88 cm). Serum creatinine 1.9 +/- 1.3 mg/dl and simplified MDRD equation 45.3 +/- 25.0 ml/min/1.73 m2 [65.8%with CKD stages 3 and 4]. 80% of patients had ophthalmologic examination and 52.8% antiplatelet treatment. Hb A1c was 7.3 +/- 1.3%, but the percentage of patients with glycated hemoglobin > 7% and 8% was 54.9 and 28.6% [only 50.2% had been seen by an endocrinologist in the last 6 months]. 52.8% of patients were treated with insulin and 44.1% with anti-diabetic drugs, although only 19.6% used the new anti-diabetic drugs. 61% of patients had an LDLc > 100 mg/dl (61% treated) and 44% had triglycerides (TG) > 150 mg/dl (72% treated). 95% of patients presented with hypertension (BP > or = 130/80 mmHg),91% were undergoing antihypertensive treatment (79.7% with angiotensin-converting enzyme inhibitors and / or angiotensin receptor blockers). 81% with microalbuminuria and 78%with established proteinuria were receiving anti-proteinuric treatment. Of the patients considered to be refractory to BP (>3 drugs), only 28.9% underwent ambulatory BP monitoring. Significant differences were observed between stages of diabetic nephropathy and glycated hemoglobin (HBA1c; p = 0.048), systolic blood pressure (SBP; p = 0.024), lipidic control (HDLc; p = 0.015 and TG; p = 0.034), anemia (Hb; p = 0.010) and CKD (creatinine and sMDRD; p = 0.000). The levels of compliance with the therapeutic objectives regarding lipid control (LDL < or = 100 mg/dl and TG< or = 150 mg/dl), BP < or = 130/80 mmHg and HbA1c < or =7% were 1 objective: 68%, 2 objectives: 21.8% and 3 objectives: only 4% of patients., Conclusions: According to the results of our study, only a reduced proportion of patients fulfilled the different therapeutic end-points indicated. Future measures will be directed at improving physician-patient relationships with the main aim of intensifying the therapeutic measures to attain better metabolic and blood pressure control, nephroprotection and prevention in the appearance of cardiovascular events.

The presence of peritoneal implants detected by computered axial tomography (CT) is usually related to mesothelial primary neoformative processes or, more frequently to peritoneal metastasis or peritoneal carcinomatosis. Although the higher prevalence of neoplastic processes in the chronic renal failure population, the association of peritoneal implants and constitutional syndrome is not always correlated to peritoneal carcinomatosis. We present the case of two patients with chronic renal failure in hemodialysis programme, with abdominal insidious clinical, constitutional syndrome and similar peritoneal implants seen by CAT: the histologic analysis of peritoneal implants gave the definitive diagnostic of secondary amyloidosis and peritoneal tuberculosis respectively.

Background: The aims of our study were to develop a three-dimensional model based on normal human osteoblasts and to determine, with this method, the osteoblastic response to sera of non-diabetic and diabetic patients on hemodialysis for chronic renal failure., Methods: A protocol for culture of osteoblastic cells in three-dimensional meshworks of bovine type I collagen was developed. The effect on cultures of sera from three groups of patients was studied: 1) 12 diabetic patients on hemodialysis [age: 65 +/- 5.2 years; sex: 6 men, 6 women; duration of dialysis treatment: 21.25 (641) months]; 2) 12 non-diabetic patients on hemodialysis [age: 65.5 +/- 5.4 years; sex: 6 men, 6 women; duration of dialysis treatment: 21.35 (6-40) months]; and 3) 12 healthy volunteer donors (age: 64.2 +/- 4.9 years; 6 men, 6 women). The three-dimensional cultures obtained were processed in the same way as undecalcified bone biopsies, sectioned and stained. A histomorphometrical study was conducted. Parameters calculated were cell number, volume of newly-formed collagen, volume of newly-formed collagen per cell, mineral volume and mineral volume per cell., Results: Number of osteoblastic cells was significantly higher in non-diabetic than in diabetic and control serum-treated cultures. Newly-formed collagen volume was significantly higher in non-diabetic serum-treated cultures than in controls. Deposited mineral volume was significantly lower in diabetic and non-diabetic serum-treated cultures compared to control serum-treated cultures., Conclusions: The model of three-dimensional culture proposed in the present study is useful in the study of different osteoblast functions including the rate of collagen formation and mineralization.

Background: The aim of this study was to determine the significance of the renal expression of ICAM-1 in IgA nephropathy (IgAN)., Patients and Method: First, we identified ICAM-1 (CD54) expression in tubular epithelial cells and interstitial leucocytes in renal biopsies from 45 patients with IgAN and 29 patients with non-glomerulonephritis nephropathy (non-GN). We then analysed the relationship between this expression and both histological and clinical data at the time of renal biopsy and after 2.4 (2) (X [SD]) years in IgAN, and 1.8 (1.5) years in non-GN., Results: In IgAN, tubular ICAM-1 positive staining was seen in 25 (55%) biopsies; it was associated with extracapillary proliferation, glomerulosclerosis involving less than 50% of glomerular area, interstitial cell infiltration and tubular atrophy. ICAM-1 positive interstitial leucocytes were 234 (307)/mm2; this expression correlated with glomerulosclerosis, tubular atrophy, interstitial fibrosis and serum creatinine (Cr) level. In patients with 50% increase in Cr level, ICAM-1 positive interstitial leucocytes were 516 (360)/mm2 as compared with 66 (87.8)/mm2 (U = 16; p < 0.005) in patients with stable Cr. In non-GN, tubular ICAM-1 expression was observed in 7 (24%) biopsies., Conclusions: Tubular and Interstitial expression of ICAM-1 can be a marker of tubulointerstitial damage in IgAN. Interstitial ICAM-1, rather than tubular ICAM-1, may predict the progression of this disease.

Burkitt's lymphoma is a tumour often associated with low immunity as acute lymphoblastic leukaemia (l3) or infection by the human immunodeficiency virus (HIV). The incidence of renal affection is variable (34-62%) and there are different aetiologies. We present a case of acute renal failure in a patient with a Burkitt's lymphoma and renal infiltration, and infected by the human immunodeficiency virus.

The first study compared two groups on dialysis: 25 patients with diabetes mellitus and 25 matched non-diabetic patients, in relation to the presence of signs of hyperparathyroidism, to assess the reported low incidence of hyperparathyroidism in these patients. The diabetic group showed significantly lower values of PTH, Alk phosphatase, percentage of patients requiring vitamin D treatment, and less evidence of hyperparathyroidism on X-ray and in bone histomorphometry. In the second study 16 patients with chronic renal failure due to diabetic nephropathy were compared to 27 patients with the same degree of renal failure of other origin, the diabetic nephropathy group showed no increase in PTH, with falling creatinine clearance. Despite this low PTH, the phosphaturia was higher in the diabetic nephropathy group (Tm PO4/C Cr: 1.94 +/- 0.43 vs 2.5 +/- 0.68). In conclusion, patients with diabetes mellitus are less prone to develop hyperparathyroidism in progressive renal failure. This could be due to a relative increase in phosphaturia during declining function.

Serum creatinine levels were determined prospectively every 2 to 3 months in 40 patients with diabetic nephropathy for a global observation period of 864 months. The monthly creatinine increasing rate was significantly lower in normotensive periods, mean arterial pressure (MAP) less than 115 mmHg, when compared with hypertensive periods, MAP greater than 125 mmHg. No significant difference was shown in periods with borderline hypertension (MAP between 115-124 mmHg). The mean creatinine increases were of 0.036 mg/dl/month, 0.3 mg/dl/month and 0.046 mg/dl/month respectively. Normotension was associated with a slowing down of the rate of decline in renal function in this group of moderate kidney failure with an initial mean serum creatinine of 2.26 mg/dl. The exposure of patients to nephrotoxics (aminoglycosides, and possibly anesthesia) significantly accelerated the decline in renal function: 0.39 mg/dl/month and 0.17 mg/dl/month respectively according to the concomitance or not of toxics and hypertension. The reported protective effect of diabetes against aminoglycosides nephrotoxicity in experimental conditions was not reflected in our clinical results. On the contrary, we suggest a possible enhanced sensibility of the diabetic patient with diabetic nephropathy to aminoglycosides leading to an acceleration of the progression of renal failure.