Steroid withdrawal after long-term medication for immunosuppressive therapy in renal transplant patients: adrenal response and clinical implications

Background. Withdrawal of steroids should be attempted after organ transplantation because of their adverse cardiovascular and metabolic effects. However, immunological, haemodynamic and symptomatic complications may occur due to the suppression of endogenous corticoid hormone synthesis under exogenous steroid intake. We have examined the effect of chronic steroid medication on adrenocortical function, and of steroid withdrawal, in immunologically stable renal transplant patients. Methods. Sixty-three patients under long-term prednisone therapy (mean±SD 36±47 months) were assessed regarding basal fasting cortisol concentration and adrenocortical stimulation by the low-dose Synacten test both prior to and after stepwise prednisone withdrawal. Renal graft function (determined as the calculated glomerular filtration rate according to the Cockroft-Gault formula), mean arterial blood pressure and clinical status were evaluated concomitantly. Results. Basal fasting cortisol concentration was clearly suppressed in 14% of patients under long-term steroid medication, and adrenocortical stimulation by the low-dose Synacten test was impaired in 31% after steroid withdrawal. About a third of all patients were symptomatic with fatigue (60%), arthralgias (60%), muscular weakness (20%), loss of appetite (20%), hypotension (15%) or headaches (5%). The incidence of symptoms was much higher in patients with low basal fasting cortisol concentration prior to steroid withdrawal, and after >2 years of steroid medication. Renal graft function, determined as glomerular filtration rate, decreased only slightly overall by ∼5%, and was more pronounced in symptomatic vs asymptomatic patients (−7 vs −2 ml/min, respectively), as was the fall in mean arterial pressure (−10 vs −4.2 mmHg, respectively). Conclusions. Adrenal function is impaired in renal transplant patients receiving long-term steroid medication as part of their immunosuppressive regimen. This may lead to mainly symptomatic complications when steroids are withdrawn. The slight decrease in glomerular filtration rate probably can be ascribed mostly to the effect of steroids on systemic renal haemodynamics. It is recommended to consider cessation of steroid medication within 48 months of therapy, and after determination of basal cortisol to identify patients with potential complication

Prospective randomised study comparing screw versus helical blade in the treatment of low-energy trochanteric fractures

Purpose: The purpose of this study was to compare femoral head placement, rates of reoperation and cephalic implant cut-out of a screw versus a blade for patients over age 60 with low energy trochanteric fractures (AO/OTA 31-A1, A2, and A3) treated either with sliding hip screw or cephalomedullary nail. Methods: After surgeon selection of either hip screw or nail, hip screw patients were randomised to either a DHS (dynamic hip system screw) or DHS blade (dynamic hip system blade), while nail patients were randomised to either a Gamma3 Trochanteric Nail or a PFNA (proximal femoral nail antirotation). This resulted in a screw group (DHS and Gamma nail), and a blade group (DHS blade and PFNA). Outcome measures included tip-apex distance and zone location of the cephalic implant, as well as reoperation and implant cut-out within the first postoperative year. Results: A total of 335 patients were randomised, 172 to a screw and 163 to a blade. There was no significant difference concerning mean tip-apex distance, percentage of patients with a tip-apex distance >25mm, and patients with a centre-centre position of the cephalic implant. There were 137 patients in the screw group and 132 in the blade group available for follow-up. They did not differ regarding rates of reoperation or cut-out (screw group = 2.9%; blade group = 1.5%). Conclusions: Both a screw and a blade performed equally well in terms of implant placement in the femoral head and outcom

Differences in Patient Characteristics Prior to TKA and THA Between Switzerland and the US

Introduction: Total knee (TKA) and hip (THA) arthroplasty results, including patient-reported outcome measures (PROMs), complication and implant survival rates, are often generalized across countries, although patient- and environment-dependent factors may differ considerably. We described and compared preoperative characteristics from two large TKA and THA cohort studies, one in Switzerland and the other in the US. Materials & methods: Patient characteristics were collected prospectively on all elective primary TKAs and THAs performed (1) at a large tertiary center in Switzerland between 1/2010 and 12/2011 and (2) in FORCE-TJR, a US diverse, large national sample between 6/2011 and 8/2012. Information was obtained on age, sex, BMI, diagnosis, medical co-morbidities, and PROMs (WOMAC pain and function, SF-12/36 physical and mental component scores). We calculated risk ratios, and mean differences, and effect sizes, to compare preoperative scores. Results: Overall, 2508 TKAs and 1,912 THAs (US) and 855 TKAs and 673 THAs (Swiss) were evaluated. U.S. patients, compared to Swiss, were younger (mean age TKA: 67 vs. 72 yrs; THA: 64 vs. 68 yrs), more obese (BMI ≥35 TKA: 27% vs. 17%; THA: 39% vs. 23%). US TKA patients had more cardiac disease, higher preoperative WOMAC pain scores (52 vs. 41 points) indicating less knee-specific pain at time of TKA. US THA patients had more diabetes (13% vs. 10%), higher WOMAC pain scores (47 vs. 40 points) indicating less hip-specific pain at the time of THA. While significant physical disability (SF) was reported in both countries, US TKA and THA patients reported lower physical function scores. Conclusion: We found substantial differences in baseline characteristics with younger age, greater obesity, in the US TKA and THA patients, and more cardiac disease (TKA), diabetes and preoperative hip pain (THA). Significant levels of disability were reported across countries. These findings call for adequate risk adjustment in cross-cultural comparisons

Fast pyrolysis processing of surfactant washed Miscanthus

Miscanthus × giganteus was subjected to pre-treatment with deionised water, hydrochloric acid or Triton X-100 surfactant, and subsequently fast pyrolysed in a fluidised bed reactor at 535 °C to obtain bio-oil. Triton X-100 surfactant was identified as a promising pre-treatment medium for removal of inorganic matter because its physicochemical nature was expected to mobilise inorganic matter in the biomass matrix. The influence of different concentrations of Triton X-100 pre-treatment solutions on the quality of bio-oil produced from fast pyrolysis was studied, as defined by a single phase bio-oil, viscosity index and water content index. The highest concentration of Triton X-100 surfactant produced the best quality bio-oil with high organic yield and low reaction water content. The calculated viscosity index from the accelerated ageing test showed that bio-oil stability improved as the concentration of Triton X-100 increased

NMR Investigation of Structures of G-Protein Coupled Receptor Folding Intermediates

Folding of G-protein coupled receptors (GPCRs) according to the two-stage model (Popot et al., Biochemistry 29(1990), 4031) is postulated to proceed in 2 steps: Partitioning of the polypeptide into the membrane followed by diffusion until native contacts are formed. Herein we investigate conformational preferences of fragments of the yeast Ste2p receptor using NMR. Constructs comprising the first, the first two and the first three transmembrane (TM) segments, as well as a construct comprising TM1-TM2 covalently linked to TM7 were examined. We observed that the isolated TM1 does not form a stable helix nor does it integrate well into the micelle. TM1 is significantly stabilized upon interaction with TM2, forming a helical hairpin reported previously (Neumoin et al., Biophys. J. 96(2009), 3187), and in this case the protein integrates into the hydrophobic interior of the micelle. TM123 displays a strong tendency to oligomerize, but hydrogen exchange data reveal that the center of TM3 is solvent exposed. In all GPCRs so-far structurally characterized TM7 forms many contacts with TM1 and TM2. In our study TM127 integrates well into the hydrophobic environment, but TM7 does not stably pack against the remaining helices. Topology mapping in microsomal membranes also indicates that TM1 does not integrate in a membrane-spanning fashion, but that TM12, TM123 and TM127 adopt predominantly native-like topologies. The data from our study would be consistent with the retention of individual helices of incompletely synthesized GPCRs in the vicinity of the translocon until the complete receptor is released into the membrane interior

Translation Levels Control Multi-Spanning Membrane Protein Expression

Attempts to express eukaryotic multi-spanning membrane proteins at high-levels have been generally unsuccessful. In order to investigate the cause of this limitation and gain insight into the rate limiting processes involved, we have analyzed the effect of translation levels on the expression of several human membrane proteins in Escherichia coli (E. coli). These results demonstrate that excessive translation initiation rates of membrane proteins cause a block in protein synthesis and ultimately prevent the high-level accumulation of these proteins. Moderate translation rates allow coupling of peptide synthesis and membrane targeting, resulting in a significant increase in protein expression and accumulation over time. The current study evaluates four membrane proteins, CD20 (4-transmembrane (TM) helixes), the G-protein coupled receptors (GPCRs, 7-TMs) RA1c and EG-VEGFR1, and Patched 1 (12-TMs), and demonstrates the critical role of translation initiation rates in the targeting, insertion and folding of integral membrane proteins in the E. coli membrane

Silencing of Vlaro2 for chorismate synthase revealed that the phytopathogen Verticillium longisporum induces the cross-pathway control in the xylem

The first leaky auxotrophic mutant for aromatic amino acids of the near-diploid fungal plant pathogen Verticillium longisporum (VL) has been generated. VL enters its host Brassica napus through the roots and colonizes the xylem vessels. The xylem contains little nutrients including low concentrations of amino acids. We isolated the gene Vlaro2 encoding chorismate synthase by complementation of the corresponding yeast mutant strain. Chorismate synthase produces the first branch point intermediate of aromatic amino acid biosynthesis. A novel RNA-mediated gene silencing method reduced gene expression of both isogenes by 80% and resulted in a bradytrophic mutant, which is a leaky auxotroph due to impaired expression of chorismate synthase. In contrast to the wild type, silencing resulted in increased expression of the cross-pathway regulatory gene VlcpcA (similar to cpcA/GCN4) during saprotrophic life. The mutant fungus is still able to infect the host plant B. napus and the model Arabidopsis thaliana with reduced efficiency. VlcpcA expression is increased in planta in the mutant and the wild-type fungus. We assume that xylem colonization requires induction of the cross-pathway control, presumably because the fungus has to overcome imbalanced amino acid supply in the xylem

Steroids in kidney transplant patients

Any evaluation of steroids in kidney transplantation is hampered by individual variability in metabolism, the lack of clinically available steroid blood levels, and overall little attention to steroid exposure. Many feel that steroids were an essential part of chronic immunosuppression in past decades but may no longer be necessary in low-risk populations when our newer and more potent drugs are used. Potential differences in long-term outcome will be unapparent in short-term antibody induction studies in low-risk patients, particularly with low on steroid doses, as may have happened in the recent, well-done Astellas trial. In many studies, the evidence for the superiority of mycophenolate (MMF) and tacrolimus (TAC) was not as strong as the evidence for the benefit of steroids in the Canadian cyclosporine study. As the practice of steroid withdrawal has increased, we have not seen the improvement in long-term graft survival that many expected with our newer agents. Steroids have immunosuppressive effects even in doses that are low by historic standards, and side effects may not justify their abandonment