The clinical manifestations of ADPKD are related to the growth of renal cysts. Renal volume has been recognised as the biomarker that is able to identify those patients at risk of complications ...(hypertension and haematuria) and at risk of progression to End Stage Renal Disease (ESRD). Recently, several scores have been introduced to predict the evolution of ADPKD. The Mayo Clinic Group developed a classification based on renal volume as measured by CT or MRI and corrected for age and height (Ht-TKV); this allowed predicting the evolution of the disease, but it has not been fully validated so far. In addition, it is used to identify patients labelled as “fast progressors” and eligible for Tolvaptan therapy according to the European Renal Association-European Dialysis and Transplant Association (ERA-EDTA) recommendations. We studied 80 patients who underwent MRI and had been classified as ADPKD typical form (class 1A-1E). A significant correlation between renal volume, hypertension, and low GFR was found (p<0.005). A progressive increase in disease severity has been found across the different Mayo classes; 41.2% were eligible for Tolvaptan therapy. The results demonstrate that the Mayo method is easy to perform and provides valid information in order to identify with rapidly progressing disease.
Background Renal osteodystrophy has been studied less extensively in predialysis than in dialysis patients. Different types of histological patterns in their natural evolution from moderate to ...advanced severity of renal insufficiency are only partially known, with special regard to adynamic bone disease and its relationship with osteomalacia. Methods We conducted a cross-sectional retrospective study on 76 unselected patients with chronic renal failure undergoing conservative treatment, with a wide range of severity of renal insufficiency. All the patients were subjected to bone biopsy for histological and histomorphometric evaluation. The patients, 44 males and 32 females ranging in age from 18 to 72 years and with serum creatinine 1.2–11.4 mg/dl, had not been exposed to aluminium-containing drugs and had never been treated with vitamin D or calcitriol. Results Ten patients had normal bone, nine were diagnosed with adynamic bone disease, 26 with mild mixed osteodystrophy, seven with predominant osteomalacia, 22 with advanced mixed osteodystrophy, and two with predominant hyperparathyroidism. Patients with adynamic bone disease had less severe chronic renal failure than the other pathological subgroups, intact PTH above the upper limit of normal, normocal-caemia, and reduced serum osteocalcin in line with a significantly lower ObS/BS. Osteomalacia was found in a more advanced stage of chronic renal failure with relative hypocalcaemia and more severe metabolic acidosis. A creatinine clearance of 20 ml/min served as a clear demarcation between this histological group and adynamic bone disease. Conclusions It is postulated that adynamic bone disease is a form of renal osteodystrophy, separate from osteomalacia, appearing when bone resistance to PTH develops, probably a transient stage to more advanced hyperparathyroid histological classes with increasing severity of chronic renal failure.
This paper describes an ultralow-power switched opamp-based integrated analog-to-digital converter (ADC) for cardiac pacemakers applications. The ADC consumption, measured on 10 chip samples and ...averaged, is 8.18 /spl mu/W (stand-by value: 1 nW) for the analog part and of 9.71 /spl mu/W (5 nW) for the digital one, using a supply battery of 2.8 V. The converter has a resolution of 10-b, its typical operating clock frequency is 32 KHz (2.9 KS/s sampling rate) and is able to reach the same resolution at 2 V (0.7 KS/s sampling rate), with a dissipation of 1 /spl mu/W and 1.3 /spl mu/W for analog and digital part, respectively.
Background
Severe secondary hyperparathyroidism (SHPT) is associated with mortality in end stage kidney disease (ESKD). Parathyroidectomy (PTX) becomes necessary when medical therapy fails, thus ...highlighting the interest to compare biochemical and clinical outcomes of patients receiving either medical treatment or surgery.
Methods
We aimed to compare overall survival and biochemical control of hemodialysis patients with severe hyperparathyroidism, treated by surgery or medical therapy followed-up for 36 months. Inclusion criteria were age older than 18 years, renal failure requiring dialysis treatment (hemodialysis or peritoneal dialysis) and ability to sign the consent form. A control group of 418 patients treated in the same centers, who did not undergo parathyroidectomy was selected after matching for age, sex, and dialysis vintage.
Results
From 82 Dialysis units in Italy, we prospectively collected data of 257 prevalent patients who underwent parathyroidectomy (age 58.2 ± 12.8 years; M/F: 44%/56%, dialysis vintage: 15.5 ± 8.4 years) and of 418 control patients who did not undergo parathyroidectomy (age 60.3 ± 14.4 years; M/F 44%/56%; dialysis vintage 11.2 ± 7.6 y). The survival rate was higher in the group that underwent parathyroidectomy (Kaplan–Meier log rank test = 0.002). Univariable analysis (HR 0.556, CI: 0.387–0.800,
p
= 0.002) and multivariable analysis (HR 0.671, CI:0.465–0.970,
p
= 0.034), identified parathyroidectomy as a protective factor of overall survival. The prevalence of patients at KDOQI targets for PTH was lower in patients who underwent parathyroidectomy compared to controls (PTX vs non-PTX: PTH < 150 pg/ml: 59% vs 21%,
p
= 0.001; PTH at target: 18% vs 37%
p
= 0.001; PTH > 300 pg/ml 23% vs 42%
p
= 0.001). The control group received more intensive medical treatment with higher prevalence of vitamin D (65% vs 41%,
p
= 0.0001), calcimimetics (34% vs 14%,
p
= 0.0001) and phosphate binders (77% vs 66%,
p
= 0.002).
Conclusions
Our data suggest that parathyroidectomy is associated with survival rate at 36 months, independently of biochemical control. Lower exposure to high PTH levels could represent an advantage in the long term.
Graphical abstract
The assay of serum peptides of bone collagen formation and degradation could potentially provide an indirect estimate of the rate of bone turnover. In our study we have measured serum levels of the ...carboxy-terminal propeptide of type I procollagen (PICP) as a marker of bone formation and serum levels of the pyridinoline cross-linked telopeptide domain of type I collagen (ICTP) as a marker of bone resorption in 53 patients (47.7 +/- 10 years, M +/- SD) on haemodialysis (for 9.5 +/- 3.8 years) and affected by renal osteodystrophy. Besides PICP and ICTP, patients were also sampled for serum intact and C-terminal PTH, osteocalcin (BGP) and alkaline phosphatase (AP). A transiliac bone biopsy for histomorphometry was also performed in all. As expected both PTH assays, BGP and AP, were correlated reciprocally and to histomorphometric parameters. As for serum levels of PICP, they were on average increased (268.5 +/- 104.9 ng/ml, M +/- SD) compared to normals (range 66-176), but not correlated to classical humoral markers of hyperparathyroidism (PTH and AP), with the exception of BGP (with a rather low r value: 0.365, P < 0.01), nor to histomorphometric indices of bone resorption and formation.
Low frequency noise measurements have been performed on Al-Si resistors, subjected to high current density (j=2/spl times/10/sup 6/ A/cm/sup 2/), in order to investigate the dependence of the ...electromigration noise on the structural and geometrical parameters. To this end five groups of samples have been used, each characterized by a different value of the average grain size D. The power spectral density S/sub v/ of the voltage fluctuations across the samples has been measured using test patterns with different widths /spl omega/ and lengths l. It has been found that S/sub v/ shows an exponential dependence on the grain dimension and a linear dependence on the shape factor F=l//spl omega/. The model previously proposed for noise generation has been integrated to take into account the observed dependence of S/sub v/ on D and F.< >
The role of metabolic acidosis on osteodystrophic bone lesions of chronic renal failure has been studied retrospectively in 24 patients, divided into two equal groups of 12, one with normal acid-base ...equilibrium (group A) and one with metabolic acidosis (group B). The two groups were found to differ significantly in serum levels of BGP (23.7 +/- 18 vs. 42.3 +/- 24 ng/ml, p < 0.02) and in several bone histomorphometric parameters such as osteoid volume (4.5 +/- 3.4 vs. 10.2 +/- 6.6%, p < 0.01), osteoid surface (27.7 +/- 18 vs. 48.4 +/- 19%, p < 0.01), single-labelled surface (7.94 +/- 2.9 vs. 15.8 +/- 9.9%, p < 0.02), mineralizing surface (60.69 +/- 26 vs. 30.89 +/- 15.8%, p < 0.003) and mineralization lag time (56.5 +/- 54 vs. 170.5 +/- 189 days, p < 0.05), with the acidotic group showing excess osteoid and a defect in mineralization. Osteomalacia was found only in the acidotic group, while the only 2 cases of adynamic bone disease (ABD) were in the nonacidotic group. Calcitriol administration, 0.25 micrograms daily for a period of 1 year, in 5 cases in group A and 6 cases in group B induced significant improvement of bone lesions mainly in group A. Two of these patients following treatment acquired the characteristics of ABD. In group B, the response to treatment was very limited, with 5 patients still showing persistence of the histological mixed type of bone disease. In conclusion, metabolic acidosis is accompanied by osteomalacia, pure or mixed variety, and shows a relative resistance to calcitriol administration. Normal acid-base equilibrium is more frequently associated with mild hyperparathyroidism and ABD, spontaneously or as a consequence of calcitriol administration.
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