Prominence of Terahertz Acoustic Surface Plasmon Excitation in Gas-Surface Interaction with Metals.

The current understanding of the dynamics of gas-surface interactions is that all of the energy lost in the collision is transferred to vibrations of the target. Electronic excitations were shown to play a marginal role except for cases in which the impinging particles have energies of several electronvolts. Here we show that this picture does not hold for metal surfaces supporting acoustic surface plasmons. Such loss, dressed with a vibronic structure, is shown to make up a prominent energy transfer route down to the terahertz region for Ne atoms scattering off Cu(111) and is expected to dominate for most metals. This mechanism determines, e.g., the drag force acting on telecommunication satellites, which are typically gold-plated to reduce overheating by sunshine. The electronic excitations can be unambiguously discerned from the vibrational ones under mild hyperthermal impact conditions.

Influence of growing conditions on the reactivity of Ni supported graphene towards CO.

Free standing graphene is chemically inert but, as recently demonstrated, CO chemisorption occurs at low crystal temperature on the single layer grown by ethene dehydrogenation on Ni(111). Such layer is inhomogeneous since different phases coexist, the relative abundance of which depends on the growth conditions. Here we show by X ray photoemission and high resolution electron energy loss spectroscopies that the attained CO coverage depends strongly on the relative weight of the different phases as well as on the concentration of carbon in the Ni subsurface region. Our data show that the chemical reactivity is hampered by the carbon content in the substrate. The correlation between the amount of adsorbed CO and the weight of the different graphene phases indicates that the top-fcc configuration is the most reactive.

CO chemisorption at vacancies of supported graphene films: a candidate for a sensor?

We investigate CO adsorption at single vacancies of graphene supported on Ni(111) and polycrystalline Cu. The borders of the vacancies are chemically inert but, on the reactive Ni(111) substrate, CO intercalation occurs. Adsorbed CO dissociates at 380 K, leading to carbide formation and mending of the vacancies, thus preventing their effectiveness in sensor applications.

Pt-functionalized Fe2O3 photoanodes for solar water splitting: the role of hematite nano-organization and the platinum redox state.

Pt/α-Fe2O3 nanocomposites were synthesized on fluorine-doped tin oxide (FTO) substrates by a sequential plasma enhanced-chemical vapor deposition (PE-CVD)/radio frequency (RF) sputtering approach, tailoring the overall Pt content as a function of sputtering time. The chemico-physical properties of the as-prepared systems were extensively investigated by means of complementary techniques, including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission-scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDXS), secondary ion mass spectrometry (SIMS), and optical absorption spectroscopy, and compared to those of the homologous Pt/α-Fe2O3 systems annealed in air prior and/or after sputtering. The obtained results evidenced that the material compositional, structural and morphological features, with particular regard to the Pt oxidation state and hematite nano-organization, could be finely tailored as a function of the adopted processing conditions. Pt/α-Fe2O3 systems were finally tested as photoanodes in photoelectrochemical (PEC) water splitting experiments, evidencing a remarkable interplay between functional performances and the above-mentioned material properties, as also testified by transient absorption spectroscopy (TAS) results.

An old workhorse for new applications: Fe(dpm)3 as a precursor for low-temperature PECVD of iron(III) oxide.

An iron(III) ß-diketonate complex, Fe(dpm)3 (Hdpm = 2,2,6,6-tetramethyl-3,5-heptanedione), has been investigated as a potential precursor for plasma enhanced chemical vapor deposition (PECVD) of iron(III) oxide nanomaterials. Thanks to the combined experimental-theoretical approach, spectroscopic properties, spin state, thermal behavior and fragmentation pathways of Fe(dpm)3 have been carefully analysed, obtaining an excellent agreement between simulation and experiment. Preliminary PECVD tests evidenced the possibility of obtaining pure and homogeneous Fe2O3 deposits with controlled nano-organization at temperatures as low as 100 °C, even on flexible plastic substrates. The present results open up intriguing perspectives for the exploitation of Fe(dpm)3 as an efficient molecular source for the preparation of nanostructured iron(III) oxides to be used in energetics and gas sensing applications.

On the performances of CuxO-TiO2 (x = 1, 2) nanomaterials as innovative anodes for thin film lithium batteries.

CuxO-TiO2 (x = 1, 2) nanomaterials are synthesized on polycrystalline Ti substrates by a convenient chemical vapor deposition (CVD) approach, based on the initial growth of a CuxO matrix (at 400 and 550 °C for x = 1 and 2, respectively) and the subsequent overdispersion of TiO2 at 400 °C. All CVD processes are carried out in an oxygen atmosphere saturated with water vapor. The obtained systems are investigated by means of glancing incidence X-ray diffraction (GIXRD), X-ray photoelectron spectroscopy (XPS), secondary ion mass spectrometry (SIMS), field emission-scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), and electrochemical experiments. Galvanostatic charge/discharge measurements indicate that Cu2O-TiO2 nanomaterials exhibit very attractive high-rate capabilities (∼400 mA h g(-1) at 1 C; ∼325 mA h g(-1) at 2 C) and good stability after 50 operating cycles, with a retention of 80% of the initial capacity. This phenomenon is mainly due to the presence of TiO2 acting as a buffer material, i.e., minimizing volume changes occurring in the electrochemical conversion. In a different way, CuO-TiO2 systems exhibit worse electrochemical performances as a consequence of their porous morphology and higher thickness. In both cases, the obtained values are among the best ever reported for CuxO-based systems, candidating the present nanomaterials as extremely promising anodes for eventual applications in thin film lithium batteries.

Thymosin-alpha 1 (Zadaxin) enhances the immunogenicity of an adjuvated pandemic H1N1v influenza vaccine (Focetria) in hemodialyzed patients: a pilot study.

BACKGROUND: Although influenza vaccination is widely recommended for immunosuppressed people, the same immune dysfunction that can increase the risk of contracting influenza might also compromise vaccine effectiveness, especially during pandemics. Clinical data have highlighted the role of adjuvants in improving vaccine efficacy. As uremic patients are especially vulnerable to infections, it is recommended that they should be vaccinated yearly against influenza. This paper presents the results of a pilot clinical trial, conducted in hemodialyzed patients with an adjuvated pandemic H1N1v influenza vaccine alone and combined with Thymosin-alpha 1. METHODS: Subjects were subdivided into 3 treatment groups receiving: the adjuvated pandemic influenza vaccine (Focetria) only (first treatment group), and the Vaccine+Thymosin alpha 1 (Zadaxin) at a dose of 3.2 and 6.4 mg (second and third treatment groups respectively). The immunoresponse was assessed on days 0, 21, 42, 84 and 168 after vaccine administration by means of Hemagglutination Inhibition (HI), Microneutralization (MN) and Single Radial Hemolysis (SRH) assays. The CHMP regards HI as the gold standard test to evaluate the immune response to influenza vaccines before influenza vaccines are licensed. The CHMP criteria are slightly different in adults (18-60-year-old subjects) and the elderly (>60 years old). Indeed, 40% of seroconversion, 70% of subjects seroprotected 21 days after vaccination, and a 2.5-fold increase in GMR (Geometric Mean Ratio) are required in adults, while in the elderly, the corresponding threshold values are: 30%, 60% and a 2-fold increase. All these criteria must be met for the licensing of a pandemic influenza vaccine. Safety evaluation was performed by means of Adverse Event (AE) recording, laboratory assays (hematology and chemistry), electrocardiogram, and assessment of vital signs. RESULTS: Three populations were considered: Intention-To-Treat (ITT) (94 patients), Per Protocol (PP) (82 patients), and Safety population (99 patients). With regard to the Geometric Mean Titer (GMT) and the Geometric Mean Ratio (GMR) of HI on Day 21 in the ITT population, both "Vaccine+Thymosin alpha 1" groups presented better results than the "Vaccine only" group. A large proportion of ITT patients in the two Vaccine+Thymosin alpha 1 groups achieved seroconversion by Day 21. On Day 42, the decrease in the GMT of HI was greater in the Vaccine+Thymosin alpha 1 groups than in the vaccine only group. Similar results were obtained in the PP population. The CHMP criteria were fully met in the groups treated with Vaccine+Thymosin alpha 1. No AE was found to be related to Thymosin alpha 1 nor to the Focetria vaccine. CONCLUSIONS: Although further studies in larger hemodialyzed populations are necessary, it can be concluded that Thymosin alpha 1 enhanced the immunogenicity of the pandemic influenza vaccine used. Moreover, it proved safe and well tolerated, and did not affect hematology or blood-chemistry values.

[Renal involvement in Fabry's disease: diagnosis, follow-up and enzyme replacement therapy]. / La nefropatia in corso di malattia di Fabry: diagnosi, follow-up e terapia enzimatica sostitutiva.

Renal involvement in Fabry's disease in males starts at an early age with microalbuminuria and proteinuria and progresses rapidly towards end-stage renal disease requiring dialysis or renal transplantation. Renal involvement, together with cardiac and cerebral damage, is responsible for the severe morbidity and mortality in patients with Fabry's disease. In heterozygous female patients renal involvement has also been documented, but the onset of renal damage occurs later and the progression to end-stage renal disease is slower. Considering the relevance of renal damage in the prognosis of Fabry's disease, it is mandatory to point out the diagnostic criteria of Fabry's nephropathy and the modalities of follow-up of patients with renal involvement. The aim of this study is also to provide recommendations regarding the diagnosis, follow-up and indication for enzyme replacement therapy in patients with Fabry's disease.

Does oral alprazolam affect ventilation? A randomised, double-blind, placebo-controlled trial.

The respiratory effects of benzodiazepines have been controversial. This investigation aimed to study the effects of oral alprazolam on ventilation. In a randomised, double-blind cross-over protocol, 20 healthy men ingested 1 mg of alprazolam or placebo in random order, 1 week apart. Ventilation was unobtrusively monitored by inductance plethysmography along with end-tidal PCO(2) and pulse oximetry 60-160 min after drug intake. Subjects were encouraged to keep their eyes open. Mean +/- SD minute ventilation 120 min after alprazolam and placebo was similar (6.21 +/- 0.71 vs 6.41 +/- 1.12 L/min, P = NS). End-tidal PCO(2) and oxygen saturation did also not differ between treatments. However, coefficients of variation of minute ventilation after alprazolam exceeded those after placebo (43 +/- 23% vs 31 +/- 13%, P < 0.05). More encouragements to keep the eyes open were required after alprazolam than after placebo (5.2 +/- 5.7 vs 1.3 +/- 2.3 calls, P < 0.05). In a multiple regression analysis, higher coefficients of variation of minute ventilation after alprazolam were related to a greater number of calls. Oral alprazolam in a mildly sedative dose has no clinically relevant effect on ventilation in healthy, awake men. The increased variability of ventilation on alprazolam seems related to vigilance fluctuations rather than to a direct drug effect on ventilation.

Renal differentiation of amniotic fluid stem cells.

OBJECTIVES: The role of stem cells in regenerative medicine is evolving rapidly. Here, we describe the application, for kidney regeneration, of a novel non-genetically modified stem cell, derived from human amniotic fluid. We show that these pluripotent cells can develop and differentiate into de novo kidney structures during organogenesis in vitro. MATERIALS AND METHODS: Human amniotic fluid-derived stem cells (hAFSCs) were isolated from human male amniotic fluid obtained between 12 and 18 weeks gestation. Green fluorescent protein and Lac-Z-transfected hAFSCs were microinjected into murine embryonic kidneys (12.5-18 days gestation) and were maintained in a special co-culture system in vitro for 10 days. Techniques of live microscopy, histology, chromogenic in situ hybridization and reverse transcriptase polymerase chain reaction were used to characterize the hAFSCs during their integration and differentiation in concert with the growing organ. RESULTS: Green fluorescent protein and Lac-Z-transfected hAFSCs demonstrated long-term viability in organ culture. Histological analysis of injected kidneys revealed that hAFSCs were capable of contributing to the development of primordial kidney structures including renal vesicle, C- and S-shaped bodies. Reverse transcriptase polymerase chain reaction confirmed expression of early kidney markers for: zona occludens-1, glial-derived neurotrophic factor and claudin. CONCLUSIONS: Human amniotic fluid-derived stem cells may represent a potentially limitless source of ethically neutral, unmodified pluripotential cells for kidney regeneration.

[Italian study on the treatment of anaemia in chronic dialysis patients switched over to less frequent doses of darbepoetin from human recombinant erythropoietin (rHuEPO)]. / Studio italiano sul trattamento dell'anemia in pazienti in terapia dialitica sostitutiva con darbepoetina alfa con una minore frequenza di somministrazione della dose rispetto all'eritropoietina ricombinante umana (rHuEPO).

BACKGROUND: Darbepoetin alpha is a novel erythropoiesis stimulating protein with unique properties as compared to recombinant human erythropoietin (rHuEPO), including a three-fold longer elimination half-life that allows for less frequent dosing. This study was aimed at testing the efficacy and safety of darbepoetin alpha in a large number of chronic dialysis patients switched from rHuEPO. METHODS: Nine hundred and fifty dialysis patients in stable treatment with rHuEPO were switched to darbepoetin alpha. Patients receiving rHuEPO 2 or 3 times weekly were switched to once weekly darbepoetin alpha and those receiving rHuEPO once weekly were switched to once every other week darbepoetin alpha. Patients received darbepoetin alpha by the same route of administration (SC or IV) as the one used for rHuEPO. The unit doses of darbepoetin alpha (10-150 microg) were titrated to maintain haemoglobin concentration within -1.0 and +1.5 g/dL of the individual mean baseline haemoglobin levels and between 10 and 13 g/dL for 24 weeks. RESULTS: The mean change in haemoglobin from baseline to the evaluation period (weeks 21-24) was statistically but not clinically significant [-0.10 g/dL (95% CI: -0.18, -0.02]. In general, the geometric mean weekly dose of study drug from screening/baseline to evaluation period remained substantially unmodified [(from 26.10 micro g/wk to 25.90 microg/wk; percentage change -0.40% (95% CI: -3.78, 3.10)]. Overall, darbepoetin alpha was well tolerated. CONCLUSIONS: The treatment of anaemia of a large dialysis patient population with unit dosing of darbepoetin alpha is effective and safe in maintaining target haemoglobin concentration at reduced dose frequency.

A locus for migraine without aura maps on chromosome 14q21.2-q22.3.

Migraine is a common and disabling neurological disease of unknown origin characterized by a remarkable clinical variability. It shows strong familial aggregation, suggesting that genetic factors are involved in its pathogenesis. Different approaches have been used to elucidate this hereditary component, but a unique transmission model and causative gene(s) have not yet been identified. We report clinical and molecular data from a large Italian pedigree in which migraine without aura (MO) segregates as an autosomal dominant trait. After exclusion of any association between MO and the known familial hemiplegic migraine and migraine with aura loci, we performed a genomewide linkage analysis using 482 polymorphic microsatellite markers. We obtained significant evidence of linkage between the MO phenotype and the marker D14S978 on 14q22.1 (maximum two-point LOD score of 3.70, at a recombination fraction of 0.01). Multipoint parametric analysis (maximum LOD score of 5.25 between markers D14S976 and D14S978) and haplotype construction showed strong evidence of linkage in a region of 10 cM flanked by markers D14S1027 and D14S980 on chromosome 14q21.2-q22.3. These results indicate the first evidence of a genetic locus associated with MO on chromosome 14.

Beneficial effects of L-carnitine in dialysis patients with impaired left ventricular function: an observational study.

BACKGROUND: Recent studies have shown that L-carnitine may improve clinical status and reduce the need for erythropoietin in dialysis patients with cardiovascular diseases. In this observational study, we investigated whether the addition of L-carnitine to conventional therapy might improve cardiac function (as assessed by M-mode and two-dimensional echocardiography) and clinical status in dialysis patients with left ventricular dysfunction. METHODS: Eleven dialysis patients with reduced left ventricular function (EF < 45%) were treated with L-carnitine for 8 months. Two-dimensional (2-D) echocardiography was performed at baseline and every 2 months up to the end of the treatment period. The dosage of erythropoietin was also monitored during the study and the patients' clinical status was assessed by a questionnaire. RESULTS: Carnitine increased mean LV ejection fraction from 32.0% to 41.8% (p < 0.05 vs baseline). There was also a slight reduction of erythropoietin dosage and an improvement of clinical status. CONCLUSIONS: Eight months' therapy with carnitine appears to improve LV function and clinical status in dialysis patients with impaired LVF.

Albumin loss in on-line hemodiafiltration.

BACKGROUND: Based on the increased hydraulic permeability of the new high permeability polyethersulfone membrane, DIAPES HF-800, we investigated the kinetics and handling of albumin in high volume on-line hemodiafiltration (HDF). METHODS: Seven patients on predilutional HDF were studied in two consecutive sessions. Blood flow rate and transmembrane pressure were continuously monitored. Spent dialysate was spilled at 20 ml/h every hour. Albumin was measured in blood and dialysate by immunonephelometry. Albumin and proteins adsorbed onto the dialyzer membrane were eluted after treatment with Triton X. Ultrafiltrates collected at 1 and 2 hours of treatment were pooled from different patients and incubated for 24 hours at 37 degrees C with bovine serum albumin (BSA). Total sulphydryl groups were evaluated using Ellmann's reagent [5, 5'-dithio-bis(2-nitrobenzoic acid)]. RESULTS: In all 7 patients, the total loss of albumin was 3.99 +/- 1.81 g, ranging between 1.09 and 6.82 g/session. Most albumin loss occurred in the first 60 min of pre-dilutional hemodiafiltration (1.92+0.83 g). There was no correlation between transmembrane pressure, urea clearance and the loss of albumin. Plasma water urea clearance values were stable over the treatment (234 +/- 14.3 ml/min). Plasma albumin concentration did not decrease during HDF sessions. Albumin adsorbed onto the dialyzers was 0.7 +/- 1.6 mg but the total amount of adsorbed proteins was much higher (130 + 90 mg). In addition, the ultrafiltrate collected during HDF sessions was able to induce oxidation of bovine serum albumin as measured by total protein sulfhydryl groups: bovine serum albumin incubated in the presence of ultrafiltrate collected at 1 hour had a sulfhydryl loss of 56.3 +/- 5.7% (p < 0.0001 vs control), and bovine serum albumin incubated with ultrafiltrate collected at 2 hours had a loss of 67.5 +/- 3.8% (p < 0.003 vs control). CONCLUSION: The present study shows the high inter- and intra-patient variability of transmembrane passage of albumin in chronically uremic patients undergoing pre-dilutional HDF. Factors involved do not seem to be correlated to transmembrane pressure but rather to an interaction with the polymer surface. Albumin adsorption was minimal and was significantly lower than that of other plasma proteins. Albumin loss during HDF seemed to have no acute impact on plasma albumin. In addition, we demonstrated the presence of prooxidative compounds able to oxidize albumin, of which extracorporeal removal by HDF procedure could be beneficial for HD patients.

Alendronate prevents further bone loss in renal transplant recipients.

The aim of this study was to investigate the effects of alendronate, calcitriol, and calcium in bone loss after kidney transplantation. We enrolled 40 patients (27 men and 13 women, aged 44.2 +/- 11.6 years) who had received renal allograft at least 6 months before (time since transplant, 61.2 +/- 44.6 months). At baseline, parathyroid hormone (PTH) was elevated in 53% of the patients and the Z scores for bone alkaline phosphatase (b-ALP) and urinary type I collagen cross-linked N-telopeptide (u-NTX) were higher than expected (p < 0.001). T scores for the lumbar spine (-2.4 +/- 1.0), total femur (-2.0 +/- 0.7), and femoral neck (-2.2 +/- 0.6) were reduced (p < 0.001). After the first observation, patients were advised to adhere to a diet containing 980 mg of calcium daily and their clinical, biochemical, and densitometric parameters were reassessed 1 year later. During this period, bone density decreased at the spine (-2.6 +/- 5.7%;p < 0.01), total femur (-1.4 +/- 4.2%; p < 0.05), and femoral neck (-2.0 +/- 3.0%; p < 0.001). Then, the patients were randomized into two groups: (1) group A-10 mg/day of alendronate, 0.50 microg/day of calcitriol, and 500 mg/day of calcium carbonate; and (2) group B-0.50 microg/day of calcitriol and 500 mg/day of calcium carbonate. A further metabolic and densitometric reevaluation was performed after the 12-month treatment period. At the randomization time, group A and group B patients did not differ as to the main demographic and clinical variables. After treatment, bone turnover markers showed a nonsignificant fall in group B patients, while both b-ALP and u-NTX decreased significantly in alendronate-treated patients. Bone density of the spine (+5.0 +/- 4.4%), femoral neck (+4.5 +/- 4.9%), and total femur (+3.9 +/- 2.8%) increased significantly only in the alendronate-treated patients. However, no trend toward further bone loss was noticed in calcitriol and calcium only treated subjects. No drug-related major adverse effect was recorded in the two groups. We conclude that renal transplanted patients continue to loose bone even in the long-term after the graft. Alendronate normalizes bone turnover and increases bone density. The association of calcitriol to this therapy seems to be advantageous for better controlling the complex abnormalities of skeletal metabolism encountered in these subjects.

Age as the major predictive factor of long-term response to splenectomy in immune thrombocytopenic purpura.

Sixty-one consecutive patients undergoing splenectomy for chronic immune thrombocytopenia were retrospectively evaluated. Platelet response was considered as complete (CR) when platelet count rose to > 100 x 109/l, partial (PR) when 30-100 x 109/l or absent (NR) if otherwise. Follow-up (mean time 7.6 years) was possible in 54 patients. Forty-eight patients (88%) had an immediate response to splenectomy (39 CR, 9 PR) whereas six (12%) were NR. Thirty-six responders (67%) had sustained remission (31 CR; 5 PR) without further treatment; thrombocytopenia recurred in 12 patients (33%). The probability curve of continued remission showed a constant relapse-rate during the first 36 months; a further step of relapse was observed beginning 70 months after surgery. The only positive predictive factor for the long-term response to splenectomy was age < 40 (P < 0.005). Neither duration of thrombocytopenia nor previous response to medical treatment (steroids and/or intravenous immunoglobulins) were related to splenectomy response.

Persistently increased bone turnover and low bone density in long-term survivors to kidney transplantation.

AIMS: There are few data on the long-term outcome of bone health in renal transplant recipients. We wanted to evaluate the prevalence of osteoporosis and related clinical fractures in long-term survivals to kidney transplantation. METHODS: We carried out a cross-sectional study of 80 males and 44 females, aged 45 +/- 1 years, who had undergone kidney transplantation (KTx) 55.6 +/- 4.6 months earlier. Patients were treated according to standard immunosuppressive protocols. RESULTS: High parathyroid hormone levels were observed in 55 out of the 124 patients (44.6%) and the prevalence of secondary hyperparathyroidism (SHPT) remained similar even when subjects were grouped according to the time elapsed since transplant. The Z scores for bone alkaline phosphatase, osteocalcin, urinary N telopeptide and galactosyl-hydroxylysine were increased as compared to normal controls, both in males and females (p < 0.05). Bone formation markers normalized, while bone resorption markers remained elevated in these patients even ten years after transplant. Vertebral and femoral osteoporosis were present in 37% and 56% of the patients, respectively, and no tendency toward a recovery in bone mass was seen even in those patients who had survived the longest time since KTx. Clinical fracture rate was 0.006 and 0.031 patient years, before and after KTx, respectively. The number of fractures was lower in patients taking lower mean daily doses of corticosteroids (p < 0.025). PTH levels positively correlated with bone alkaline phosphatase, osteocalcin and N telopeptide. CONCLUSION: In conclusion, bone density is decreased and bone turnover increased even many years after KTx, with persistent SHPT and corticosteroid use being the main pathogenetic factors.

Role of insulin-like growth factor-I in primary osteoporosis: a correlative study.

Osteoporosis is characterized by impairment of bone mass and deterioration of bone microscopic structure, resulting in increased bone fragility and susceptibility to fracture. Recent reports have indicated that reduced plasma levels of IGF-I are associated with osteoporosis in both males and females. Moreover, there is accumulating clinical evidence that treatment with GH or IGF-I has beneficial effects on bone mass and bone remodeling in men with idiopathic osteoporosis, in the elderly and in hypopituitary patients. As correlative studies on IGF-I, IGF-BP3 and bone mass in the elderly are lacking, we studied the relationships between serum IGF-I, IGF-BP3, bone mineral density (BMD), body mass index (BMI), calciotropic hormones and age in 102 premenopausal and postmenopausal women. Our study indicates that the reduction of the anabolic processes mediated by IGF-I may account for the slow and progressive loss of bone mass that take place after the age of 40-50 years. In addition, nutritional caloric or proteic deficit may add to the effects of GH, age and other factors in decreasing IGF-I synthesis and therefore further contribute to the development of primary osteoporosis.

Parathyroid hormone and bone metabolism in kidney-transplanted patients.

BACKGROUND: Decreases in bone mass and increased susceptibility to fractures are well-recognized complications in organ transplants. SUBJECTS AND METHODS: We performed a cross-sectional study on 60 patients (40 males, 20 females, mean age 43.2 +/- 1.06, SE range 22 - 70) who underwent kidney transplantation (KTX) 55.6 +/- 4.5 months before. Blood and 24-hour urine samples were analyzed for the main parameters of mineral metabolism, and also for osteocalcin (BGP), bone alkaline phosphatase (b-ALP, urine N-telopeptid (u-NTx) and urine galactosyl-hydroxylysine (u-Ghyl). DEXA scan of the lumbar spine (LS) and proximal femur (PF) and ultrasound determination of the heel (stiffness) was also performed. RESULTS: T-score values for bone density (BD) were 2.14 +/- 0.11 SD's for LS, -2.56 +/- 0.09 for PF and 2.49 +/- 0.15 for stiffness. There were 29 peripheral fractures in 16 patients. The rate of fractures before KTX were 0.0011 per patient/year and 0.0005 after transplantation (p < 0.02). When expressed as number of SD's with respect to normal controls, BGP (1.48 +/- 0.23), b-ALP (0.95 +/- 0.19), u-NTx excretion correlated negatively with BD at the femoral neck (p < 0.02) and trochanter (p < 0.03). Cumulative steroids intake were negatively correlated with b-ALP positively (p < 0.05). Current CsA was positively correlated with b-ALP (p < 0.001). Both cumulative steroid (p < 0.02) and CSA (p < 0.01) intakes were negatively correlated with BD at Wards triangle. CONCLUSIONS: Our data demonstrate an important bone depletion at each stage KTX. PTH plays a major role in the observed increase in bone turnover, exacerbating the negative effects on the bone on immunosuppressive treatment. Glucocorticosteroid therapy is an important risk factor for osteoporosis in this setting also.