p70S6 kinase phosphorylation for pharmacodynamic monitoring

Inhibitors of the mammalian target of rapamycin (mTOR) are administered as immunosuppressant as well as antineoplastic agents. Because of the narrow therapeutic index of mTOR inhibitors, drug monitoring is required, and this is usually done by measuring blood drug levels. Increasing knowledge of the signaling pathways of the mTOR protein kinase provides an opportunity for pharmacodynamic drug monitoring. With the different laboratory methods it is becoming possible to measure new biomarkers to control the influence of mTOR activity. One of these biomarkers is phospho-S6 kinase, with its isoform p70S6K.

Critical evaluation of rituximab rescue in 27 patients with different types of kidney disease

AIM

Rituximab is increasingly being used in the treatment of patients with kidney disease. We evaluated our clinical experience at the Ulm University Hospital.

METHODS

Since 2004, we have administered rituximab as rescue therapy to twenty-seven patients with kidney disease non-responsive to standard treatment. Indications for rituximab were progressive loss of kidney function in thirteen cases; nephrotic syndrome in five cases; humoral rejection after kidney transplantation in five cases and single cases of catastrophic antiphospholipid syndrome (CAPS), pre-emptive removal of ABO incompatible antibodies, pre-transplant removal of panel-reactive antibodies (PRA), and post-transplant lymphoproliferative disease (PTLD). Sixteen patients were treated with both, plasmapheresis and rituximab.

RESULTS

Kidney function recovered in five of thirteen cases. Nephrotic syndrome response was observed in two of five cases. In two of five patients with humoral rejection, kidney transplant function could be preserved. Antiphospholipid antibodies, blood group A antibodies and panel reactive antibodies successfully were reduced, and remission was achieved in the case of the patient with PTLD. Four patients died (15%). Adverse events (N.=10) and infectious complications (N.=15) were most likely due to immunosuppression in general and not to rituximab alone. Toxic leukoencephalopathy was a serious but reversible complication in three cases and occurred particularly after the administration of high-dose rituximab (>375 mg/m2).

CONCLUSION

Rituximab rescue was successful in 48% of our cases (13 of 27). Rituximab did not increase the complication risk of standard immunosuppression. But toxic leukoencephalopathy was identified as a significant rituximab complication.

Homozygous carriers of the G allele of rs4664447 of the glucagon gene (GCG) are characterised by decreased fasting and stimulated levels of insulin, glucagon and glucagon-like peptide (GLP)-1

AIMS/HYPOTHESIS

The glucagon gene (GCG) encodes several hormones important for energy metabolism: glucagon, oxyntomodulin and glucagon-like peptide (GLP)-1 and -2. Variants in GCG may associate with type 2 diabetes, obesity and/or related metabolic traits.

METHODS

GCG was re-sequenced as a candidate gene in 865 European individuals. Twenty-nine variants were identified. Four variants that were considered to have a likelihood for altered functionality: rs4664447, rs7581952, Ile158Val and Trp169Ter, were genotyped in 17,584 Danes.

RESULTS

When examined in 5,760 treatment-naive individuals, homozygous carriers of the low frequency (minor allele frequency 2.3%) G allele of rs4664447, predicted to disrupt an essential splice enhancer binding site, had lower levels of fasting plasma glucose (mean ± SD, 4.8 ± 1.2 vs 5.5 ± 0.8 mmol/l, p = 0.004); fasting serum insulin (22 ± 14 vs 42 ± 27 pmol/l, p = 0.04); glucose-stimulated serum insulin (159 ± 83 vs 290 ± 183 pmol/l, p = 0.01) and adult height (165 ± 10 vs 172 ± 9 cm, p = 0.0009) compared with A allele carriers. During oral glucose tolerance and hyperglycaemic arginine stimulation tests, the plasma AUC for GLP-1 (730 ± 69 vs 1,334 ± 288 pmol/l × min, p = 0.0002) and basal and stimulated levels of serum insulin and plasma glucagon were ∼50% decreased (p < 0.001) among three homozygous carriers compared with nine matched wild-type carriers. rs7581952, Ile158Val and Trp169Ter (where 'Ter' indicates 'termination') variants of GCG did not significantly associate or co-segregate with the metabolic traits examined.

CONCLUSIONS/INTERPRETATION

Re-sequencing of GCG revealed a low frequency intronic variant, rs4664447, and follow-up physiological studies suggest that this variant in homozygous form may cause decreased fasting and stimulated levels of insulin, glucagon and GLP-1. Overall, our findings suggest that variation in GCG has no major impact on carbohydrate metabolism in the study populations examined.

Skin disinfection by plasma-tissue interaction: comparison of the effectivity of tissue-tolerable plasma and a standard antiseptic

Wound healing disorders frequently occur due to biofilm formation on wound surfaces requiring conscientious wound hygiene. Often, the application of conventional liquid antiseptics is not sufficient and sustainable as (1) the borders and the surrounding of chronic wounds frequently consist of sclerotic skin, impeding an effectual penetration of these products, and (2) the hair follicles representing the reservoir for bacterial recolonization of skin surfaces are not affected. Recently, it has been reported that tissue-tolerable plasma (TTP), which is used at a temperature range between 35 and 45°C, likewise has disinfecting properties. In the present study, the effectivity of TTP and a standard liquid antiseptic was compared in vitro on porcine skin. The results revealed that TTP was able to reduce the bacterial load by 94%, although the application of the liquid antiseptic remained superior as it reduced the bacteria by almost 99%. For in vivo application, however, TTP offers several advantages. On the one hand, TTP enables the treatment of sclerotic skin as well, and on the other hand, a sustainable disinfection can be realized as, obviously, also the follicular reservoir is affected by TTP.

Targeting the vitamin D receptor inhibits the B cell-dependent allergic immune response

BACKGROUND

1α,25-dihydroxyvitamin D(3) (calcitriol), the biologically active form of vitamin D, is an immunomodulatory hormone, e.g. it inhibits IgE synthesis in B cells. As its clinical application is limited by hypercalcemia, synthetic vitamin D receptor (VDR) agonists that mediate immunomodulatory activities without adverse hypercalcemic effects are of great interest. This study aimed to investigate the impact of a low-calcemic VDR agonist on the IgE immune response in vitro and in vivo.

METHODS

Human peripheral B cells were cultured under IgE inducing conditions in the presence of VDR ligands. B cells were analyzed by quantitative RT-PCR, enzyme-linked immunosorbent assays, enzyme-linked immunospot technique, and flow cytometry. BALB/c mice were sensitized with ovalbumin (OVA)/alum followed by the therapeutic VDR agonist treatment and analyzed regarding the humoral immunoglobulin profile.

RESULTS

The natural VDR ligand calcitriol, but also a low-calcemic VDR agonist, profoundly suppressed IgE production by human peripheral B cells by 63.9 ± 5.9%. The potential mechanisms involved are the reduction of the transcript for activation-induced deaminase (AID) and the reduction of IgE immunoglobulin-secreting cells by 68.1 ± 12.7%. By using an in vivo approach, we finally demonstrate that the humoral IgE response in a type I allergy mouse model was impaired by the VDR agonist.

CONCLUSION

Our results show that targeting the VDR modulates the humoral immune response including IgE. Whether it might be useful for clinical applications has to be determined in appropriate clinical trials.

[The radial forearm phalloplasty with prelaminated urethra: a report of our learning curve during the last 6 years]

Several methods for complete phalloplasty are reported in the current literature. However, a unique technique has not been established in specialized centers so far. The radial forearm phalloplasty and the free fibular flap are the most common procedures for neophallus construction. There are 3 modifications for the radial forearm flap: the double folded "tube into tube" flap with a central vascularized urethra, the radial forearm flap with a vascularized urethra in the ulnar part of the flap and the radial forearm phalloplasty with a prelaminated neo-urethra using a full thickness skin graft. A series of 19 phalloplasties was performed between 2003 and 2010 in our department. The first cases of the series were conducted using the "tube-into-tube-technique" with the central urethra. However, the surgical concept was changed for the majority of cases (n=15) due to complications and not satisfying esthetic results. The phalloplasties were performed using the technique with a prelaminated urethra from 2005 on. The urethra prelamination was carried out using a full thickness skingraft 6 months before the actual phalloplasty procedure. Skin harvest was performed during mastectomy in the ideal case but otherwise alternatively from the lower belly. The complication rate in our series was comparable to the results of other authors. The esthetic results were very satisfying and the donor side morbidity was kept as minor as possible. All other techniques for radial forearm phalloplasty require the elevation of an additional 3.5-4 cm wide and 14-18 cm long adipocutaneous stripe at the forearm, which is used for construction of the urethra.

Antiseptic efficacy and tolerance of tissue-tolerable plasma compared with two wound antiseptics on artificially bacterially contaminated eyes from commercially slaughtered pigs

AIM

To compare the tissue tolerance and efficacy of two wound antiseptics with tissue-tolerable plasma (TTP) on enucleated contaminated eyes from slaughtered pigs in order to draw consequences for the use of TTP on wounds.

METHOD

The corneas of extracted eyes were contaminated with Staphylococcus aureus or Pseudomonas aeruginosa. One and 10 min after application of 10% povidone (PVP)-iodine and 0.04% polyhexanide, respectively, the eyes were rinsed with inactivating solution. To test TTP, the plasma pen meandered over the eyes at a speed of 30 mm/s and a distance of 5 mm; the eyes were then rinsed with balanced salt solution. The reduction factor was calculated by the difference between the logarithm of colony-forming units in the rinse before and after antisepsis or TTP application.

RESULTS

The efficacy of TTP (reduction factor 2.4-2.9) was significantly higher (p < 0.001) than that of PVP-iodine and polyhexanide (reduction factor 1.7-2.1).

CONCLUSION

TTP is more effective than the tested wound antiseptics. The lack of histological damage to the eyes of slaughtered pigs would seem to make its use as a wound antiseptic a viable alternative. In contrast to antiseptics, it supplies additional energy in the form of heat, electric fields and radicals by TTP.

[Observations during basic care after the earthquake in Port-au-Prince, Haiti on January 12, 2010]

Provision of basic health care to earthquake victims in camps in Haiti indicated that the population was in relatively good health. It also allowed early detection of possible epidemic outbreak.

Polyneuropathy associated with cholesterol crystal embolism

INTRODUCTION

Cholesterol crystal embolism complicating arterial catheterization usually presents as a multiorgan disease with renal failure, abdominal problems, and skin manifestations.

METHODS

We present a patient with hypertension and generalized arteriosclerosis who presented with muscle weakness, diffuse pain in the extremities, and renal failure 3 weeks after coronary catheterization and angioplasty of the right coronary artery. Muscle weakness progressed during the following months.

RESULTS

Nerve conduction studies and nerve biopsy showed severe axonal nerve injury. Biopsy of the kidney revealed the diagnosis of cholesterol crystal embolism.

CONCLUSION

The clinical presentation indicates a direct association of cholesterol crystal embolism and polyneuropathy. Although cholesterol crystal embolism represents a rare cause of polyneuropathy, it should be considered in patients with acute onset polyneuropathy and sudden onset multiorgan disease after arterial catheterization.

Long-term exendin-4 treatment delays natural deterioration of glycaemic control in diabetic Goto-Kakizaki rats

AIM

The glucagon-like peptide-1 (GLP-1) receptor agonist, exendin-4, has previously been shown to delay the onset of diabetes when administered to Goto-Kakizaki (GK) rats in the prediabetic period. The present study aimed to evaluate whether long-term administration of exendin-4 to GK rats in the diabetic period would improve their diabetes and how glycaemic control was affected following drug wash-out.

METHODS

Glycaemic control was assessed in diabetic GK rats during 12 weeks of exendin-4 or vehicle treatment. Moreover, some animals were followed for an additional 9 weeks without treatment.

RESULTS

Glycaemic control was seen to deteriorate in vehicle-treated animals, as assessed by increased glycated haemoglobin A1c (HbA1c), whereas HbA1c improved in exendin-4-treated animals. Following an additional 9 weeks without treatment, glycaemic control in exendin-4-treated animals remained below baseline value and thus remained significantly lower than that of vehicle-treated animals. Following exendin-4 administration, oral glucose tolerance tests revealed greatly reduced glucose and insulin excursions compared with vehicle-treated animals, whereas following overnight drug wash-out, only little difference was seen, suggesting that the improvement in glycaemic control may have been obtained primarily by increased postprandial control. No significant differences were observed in pancreatic islet morphology or islet hormone content.

CONCLUSIONS

Exendin-4 treatment improved glycaemic control in diabetic GK rats, independent of changes in beta-cell mass. Additionally, progression of the disease seemed to be delayed because the improvement in HbA1c was still apparent 9 weeks after cessation of treatment.

Adherence to prescribed oral medication in adult patients undergoing chronic hemodialysis: a critical review of the literature

Objective

Poor adherence to complex multimodal therapies is a widely recognized problem in the daily care of dialysis patients, contributing to excess morbidity and mortality of this population. While a few studies have been devoted to understanding patient nonadherence, their results were somewhat controversial. The goals of this review are to quantify nonadherence to certain oral medications, to raise awareness of factors that may cause problems in a patient's adherence to this treatment, and to describe strategies that may be used to improve adherence to prescribed pharmacotherapy.

Methods

A systematic literature review in the MEDLINE and PubMed database (1971-2008) was performed. Quantitative studies, which accurately indicated the total percentages of nonadherence to oral medication in adult patients receiving chronic hemodialysis, were identified.

Results

A total of 19 studies fulfilled the search criteria. Rates of nonadherence to the oral medication ranged from 3 - 80%. More than half of the included studies reported nonadherence rates of ≥ 50% (mean 67%). The use of phosphate binding therapy was the prevalent surveyed oral medication. Self reports, structured interviews, and predialysis serum phosphate levels were the most frequent assessment tools used to record adherence rates. Limitations of the reviewed studies included small patient cohorts, inconsistent definitions of adherence, and a lack of standardized methods for measuring nonadherence.

Conclusions

Nonadherence to oral medication in hemodialysis patients is still an underestimated, but life-threatening behaviour.

Insights on protein-DNA recognition by coarse grain modelling

Coarse grain modelling of macromolecules is a new approach, potentially well adapted to answer numerous issues, ranging from physics to biology. We propose here an original DNA coarse grain model specifically dedicated to protein-DNA docking, a crucial, but still largely unresolved, question in molecular biology. Using a representative set of protein-DNA complexes, we first show that our model is able to predict the interaction surface between the macromolecular partners taken in their bound form. In a second part, the impact of the DNA sequence and electrostatics, together with the DNA and protein conformations on docking is investigated. Our results strongly suggest that the overall DNA structure mainly contributes in discriminating the interaction site on cognate proteins. Direct electrostatic interactions between phosphate groups and amino acid side chains strengthen the binding. Overall, this work demonstrates that coarse grain modeling can reveal itself a precious auxiliary for a general and complete description and understanding of protein-DNA association mechanisms.

[Health behaviour and health-risk behaviour among job-seekers: a screening at an employment agency]

AIM

The purpose of this study was to investigate the distribution of health behaviours and health-risk behaviours among three groups of job-seeking persons at employment agencies: short-term unemployed, long-term unemployed, and non-unemployed (e.g., threatened by job loss) persons. A related aim was to identify the general willingness of persons recruited at employment agencies to participate in a study regarding health behaviours.

METHOD

At the employment agency Greifswald (Western Pomerania, Germany), over a period of two weeks, all job-seeking persons while waiting were personally asked to participate in a screening regarding health behaviours.

RESULTS

A total of 1672 persons (M=34 years, 54% women), that is 74.3% of all job-seekers, participated in the screening. Regarding physical activity, fruit and vegetable intake, smoking, at-risk drinking, drug use and overweight, all three groups showed a lack of health behaviour and increased risky behaviour compared to the general population or nation-wide guidelines. ANOVAs, chi (2) tests and logistic regressions showed significant differences among the three groups. Non-unemployed persons were more likely to report a healthier life style compared to both unemployed groups. Long-term unemployed persons had a higher risk of smoking (OR=1.56; CI 95%=1.14-2.12) and of using drugs (OR=2.79; CI 95%=1.30-5.98) compared to short-term unemployed persons.

CONCLUSIONS

The high participation rate, along with the high rates of risky behaviour and lack of health behaviour indicate the demand for intervention programs for job-seekers and the opportunity of using this setting for proactive interventions that could reach more than 70% of all job-seekers.