Activation of c-Jun in the nuclei of neurons of the CA-1 in thrombin preconditioning occurs via PAR-1.

Recently it has been shown that the c-Jun N-terminal kinase (JNK) plays a role in thrombin preconditioning (TPC) in vivo and in vitro. To investigate further the pathways involved in TPC, we performed an immunohistochemical study in hippocampal slice cultures. Here we show that the major target of JNK, the AP-1 transcription factor c-Jun, is activated by phosphorylation in the nuclei of neurons of the CA1 region by using phospho-specific antibodies against the two JNK phosphorylation sites. The activation is early and transient, peaking at 90 min and not present by 3 hr after low-dose thrombin administration. Treatment of cultures with a synthetic thrombin receptor agonist results in the same c-Jun activation profile and protection against subsequent OGD, both of which are prevented by specific JNK inhibitors, showing that thrombin signals through PAR-1 to JNK. By using an antibody against the Ser 73 phosphorylation site of c-Jun, we identify possible additional TPC substrates.

Activation of c-Jun in the nuclei of neurons of the CA-1 in thrombin preconditioning occurs via PAR-1.

Recently it has been shown that the c-Jun N-terminal kinase (JNK) plays a role in thrombin preconditioning (TPC) in vivo and in vitro. To investigate further the pathways involved in TPC, we performed an immunohistochemical study in hippocampal slice cultures. Here we show that the major target of JNK, the AP-1 transcription factor c-Jun, is activated by phosphorylation in the nuclei of neurons of the CA1 region by using phospho-specific antibodies against the two JNK phosphorylation sites. The activation is early and transient, peaking at 90 min and not present by 3 hr after low-dose thrombin administration. Treatment of cultures with a synthetic thrombin receptor agonist results in the same c-Jun activation profile and protection against subsequent OGD, both of which are prevented by specific JNK inhibitors, showing that thrombin signals through PAR-1 to JNK. By using an antibody against the Ser 73 phosphorylation site of c-Jun, we identify possible additional TPC substrates.

Elf-1 contributes to the function of the complex interleukin (IL)-2-responsive enhancer in the mouse IL-2 receptor alpha gene.

Lymphocytes regulate their responsiveness to IL-2 through the transcriptional control of the IL-2R alpha gene, which encodes a component of the high affinity IL-2 receptor. In the mouse IL-2R alpha gene this control is exerted via two regulatable elements, a promoter proximal region, and an IL-2-responsive enhancer (IL-2rE) 1.3 kb upstream. In vitro and in vivo functional analysis of the IL-2rE in the rodent thymic lymphoma-derived, CD4- CD8- cell line PC60 demonstrated that three separate elements, sites I, II, and III, were necessary for IL-2 responsiveness; these three sites demonstrate functional cooperation. Site III contains a consensus binding motif for members of the Ets family of transcription factors. Here we demonstrate that Elf-1, an Ets-like protein, binds to site III and participates in IL-2 responsiveness. In vitro site III forms a complex with a protein constitutively present in nuclear extracts from PC60 cells as well as from normal CD4- CD8- thymocytes. We have identified this molecule as Elf-1 according to a number of criteria. The complex possesses an identical electrophoretic mobility to that formed by recombinant Elf-1 protein and is super-shifted by anti-Elf-1 antibodies. Biotinylated IL-2rE probes precipitate Elf-1 from PC60 extracts provided site III is intact and both recombinant and PC60-derived proteins bind with the same relative affinities to different mutants of site III. In addition, by introducing mutations into the core of the site III Ets-like motif and comparing the corresponding effects on the in vitro binding of Elf-1 and the in vivo IL-2rE activity, we provide strong evidence that Elf-1 is directly involved in IL-2 responsiveness. The nature of the functional cooperativity observed between Elf-1 and the factors binding sites I and II remains unresolved; experiments presented here however suggest that this effect may not require direct interactions between the proteins binding these three elements.

The fou2 gain-of-function allele and the wild-type allele of Two Pore Channel 1 contribute to different extents or by different mechanisms to defense gene expression in Arabidopsis.

The fatty acid oxygenation up-regulated 2 (fou2) mutant in Arabidopsis thaliana creates a gain-of-function allele in a non-selective cation channel encoded by the Two Pore Channel 1 (TPC1) gene. This mutant genetically implicates cation fluxes in the control of the positive feedback loop whereby jasmonic acid (JA) stimulates its own synthesis. In this study we observed extensive transcriptome reprogramming in healthy fou2 leaves closely resembling that induced by treatment with methyl jasmonate, biotic stresses and the potassium starvation response. Proteomic analysis of fou2 leaves identified increased levels of seven biotic stress- and JA-inducible proteins. In agreement with these analyses, epistasis studies performed by crossing fou2 with aos indicated that elevated levels of JA in fou2 are the major determinant of the mutant phenotype. In addition, generation of fou2 aba1-5, fou2 etr1-1 and fou2 npr1-1 double mutants showed that the fou2 phenotype was only weakly affected by ABA levels and unaffected by mutations in NPR1 and ETR1. The results now suggest possible mechanisms whereby fou2 could induce JA synthesis/signaling early in the wound response. In contrast to fou2, transcriptome analysis of a loss-of-function allele of TPC1, tpc1-2, revealed no differential expression of JA biosynthesis genes in resting leaves. However, the analysis disclosed reduced mRNA levels of the pathogenesis-related genes PDF1.2a and THI2.1 in healthy and diseased tpc1-2 leaves. The results suggest that wild-type TPC1 contributes to their expression by mechanisms somewhat different from those affecting their expression in fou2.

Expression of E-Selectin and Vascular Cell Adhesion Molecule-1 in So-Called 'Negative' Appendices: First Results to Support the Pathological Diagnosis in Borderline Cases.

Background: Since the rate of histologically 'negative' appendices still ranges between 15 and 20%, appendicitis in 'borderline' cases remains a challenging disease. As previously described, cell adhesion molecule expression correlates with different stages of appendicitis. Therefore, it was of interest to determine whether the 'negative' appendix correlated with the absence of E-selectin or vascular cell adhesion molecule-1 (VCAM-1). Methods: Nineteen grossly normal appendices from a series of 120 appendectomy specimens from patients with suspected appendicitis were analysed in frozen sections for the expression of E-selectin and VCAM-1. As control, 5 normal appendices were stained. Results: This study showed a coexpression of E-selectin and VCAM-1 in endothelial cells in early and recurrent appendicitis. In patients with symptoms for less than 6 h, only E-selectin was detected. Cases with fibrosis and luminal obliteration were only positive for VCAM-1. In cases of early appendicitis with symptoms of less than 6 h duration, a discordance between histological and immunohistochemical results was found. Conclusions: This report indicates that E-selectin and VCAM-1 expression could be useful parameters in the diagnosis of appendicitis in borderline cases.

A large-scale genetic validation study coupled with in vitro analyses reveal a role for vitamin Dsignaling in the pathogenesis and response to treatment of hepatitis C virus infection

Background and Aims: Vitamin D is an important modulatorof numerous cellular processes. Some of us recently observedan association of the 1a-hydroxylase promoter polymorphismCYP27B1-1260 rs10877012 with sustained virologic response (SVR)in a relatively small number of German patients with chronichepatitis C. In the present study, we aimed to validate thisassociation in a large and well characterized patient cohort, theSwiss Hepatitis C Cohort Study (SCCS). In addition, we examinedthe effect of vitamin D on the hepatitis C virus (HCV) life cyclein vitro.Methods: CYP27B1-1260 rs10877012 and IL28B rs12979860 singlenucleotide polymorphisms (SNPs) were genotyped in 1049 patientswith chronic hepatitis C from the SCCS, of whom 698 were treatedwith pegylated interferon-a (PEG-IFN-a) and ribavirin. In addition,112 patients with spontaneous clearance of HCV were examined.SNPs were correlated with variables reflecting the natural courseand treatment outcome of chronic hepatitis C. The effect of1,25-(OH)2D3 (calcitriol) on HCV replication and viral particleproduction was investigated in vitro using human hepatoma celllines (Huh-7.5) harbouring subgenomic replicons and cell culturederivedHCV.Results: The CYP27B1-1260 rs10877012 genotype was notassociated with SVR in patients with the good-response IL28Brs1279860 CC genotype. However, in patients with poor-responseIL28B rs1279860 genotype CT and TT, CYP27B1-1260 rs10877012was a significant independent predictor of SVR (15% difference inSVR between rs10877012 genotype AA vs. CC, p = 0.030, OR = 1.495,95% CI = 1.038-2.152). The CYPB27-1260 rs10877012 genotype wasneither associated with spontaneous clearance of HCV, nor withliver fibrosis progression rate, inflammatory activity of chronichepatitis C, or HCV viral load. Physiological doses of 1,25-(OH)2D3did not significantly affect HCVRNA replication or infectiousparticle production in vitro.Conclusions: The results of this large-scale genetic validationstudy reveal a role of vitamin D metabolism in the responseto treatment in chronic hepatitis C, but 1,25-(OH)2D3 does notexhibit a significant direct inhibitory antiviral effect. Thus, theability of vitamin D to modulate immunity against HCV shouldbe investigated.

The Discrimination of Colored Acrylic, Cotton, and Wool Textile Fibers Using Micro-Raman Spectroscopy. Part 1 : In Situ Detection and Characterization of Dyes

Raman spectroscopy has been applied to characterize fiber dyes and determine the discriminating ability of the method. Black, blue, and red acrylic, cotton, and wool samples were analyzed. Four excitation sources were used to obtain complementary responses in the case of fluorescent samples. Fibers that did not provide informative spectra using a given laser were usually detected using another wavelength. For any colored acrylic, the 633-nm laser did not provide Raman information. The 514-nm laser provided the highest discrimination for blue and black cotton, but half of the blue cottons produced noninformative spectra. The 830-nm laser exhibited the highest discrimination for red cotton. Both visible lasers provided the highest discrimination for black and blue wool, and NIR lasers produced remarkable separation for red and black wool. This study shows that the discriminating ability of Raman spectroscopy depends on the fiber type, color, and the laser wavelength.

Role of retroviral restriction factors in the interferon-α-mediated suppression of HIV-1 in vivo.

The antiviral potency of the cytokine IFN-&#945; has been long appreciated but remains poorly understood. A number of studies have suggested that induction of the apolipoprotein B mRNA editing enzyme, catalytic polypeptide 3 (APOBEC3) and bone marrow stromal cell antigen 2 (BST-2/tetherin/CD317) retroviral restriction factors underlies the IFN-&#945;-mediated suppression of HIV-1 replication in vitro. We sought to characterize the as-yet-undefined relationship between IFN-&#945; treatment, retroviral restriction factors, and HIV-1 in vivo. APOBEC3G, APOBEC3F, and BST-2 expression levels were measured in HIV/hepatitis C virus (HCV)-coinfected, antiretroviral therapy-naïve individuals before, during, and after pegylated IFN-&#945;/ribavirin (IFN-&#945;/riba) combination therapy. IFN-&#945;/riba therapy decreased HIV-1 viral load by -0.921 (±0.858) log(10) copies/mL in HIV/HCV-coinfected patients. APOBEC3G/3F and BST-2 mRNA expression was significantly elevated during IFN-&#945;/riba treatment in patient-derived CD4+ T cells (P < 0.04 and P < 0.008, paired Wilcoxon), and extent of BST-2 induction was correlated with reduction in HIV-1 viral load during treatment (P < 0.05, Pearson's r). APOBEC3 induction during treatment was correlated with degree of viral hypermutation (P < 0.03, Spearman's &#961;), and evolution of the HIV-1 accessory protein viral protein U (Vpu) during IFN-&#945;/riba treatment was suggestive of increased BST-2-mediated selection pressure. These data suggest that host restriction factors play a critical role in the antiretroviral capacity of IFN-&#945; in vivo, and warrant investigation into therapeutic strategies that specifically enhance the expression of these intrinsic immune factors in HIV-1-infected individuals.

Sparse regularization for fiber ODF reconstruction: from the suboptimality of &#8467;2 and &#8467;1 priors to &#8467;0.

Diffusion MRI is a well established imaging modality providing a powerful way to probe the structure of the white matter non-invasively. Despite its potential, the intrinsic long scan times of these sequences have hampered their use in clinical practice. For this reason, a large variety of methods have been recently proposed to shorten the acquisition times. Among them, spherical deconvolution approaches have gained a lot of interest for their ability to reliably recover the intra-voxel fiber configuration with a relatively small number of data samples. To overcome the intrinsic instabilities of deconvolution, these methods use regularization schemes generally based on the assumption that the fiber orientation distribution (FOD) to be recovered in each voxel is sparse. The well known Constrained Spherical Deconvolution (CSD) approach resorts to Tikhonov regularization, based on an &#8467;(2)-norm prior, which promotes a weak version of sparsity. Also, in the last few years compressed sensing has been advocated to further accelerate the acquisitions and &#8467;(1)-norm minimization is generally employed as a means to promote sparsity in the recovered FODs. In this paper, we provide evidence that the use of an &#8467;(1)-norm prior to regularize this class of problems is somewhat inconsistent with the fact that the fiber compartments all sum up to unity. To overcome this &#8467;(1) inconsistency while simultaneously exploiting sparsity more optimally than through an &#8467;(2) prior, we reformulate the reconstruction problem as a constrained formulation between a data term and a sparsity prior consisting in an explicit bound on the &#8467;(0)norm of the FOD, i.e. on the number of fibers. The method has been tested both on synthetic and real data. Experimental results show that the proposed &#8467;(0) formulation significantly reduces modeling errors compared to the state-of-the-art &#8467;(2) and &#8467;(1) regularization approaches.

Large-scale imatinib dose-concentration-effect study in CML patients under routine care conditions.

This observational study analyzed imatinib pharmacokinetics and response in 2478 chronic myeloid leukemia (CML) patients. Data were obtained through centralized therapeutic drug monitoring (TDM) at median treatment duration of &#8805;2 years. First, individual initial trough concentrations under 400mg/day imatinib starting dose were estimated. Second, their correlation (C^min(400mg)) with reported treatment response was verified. Low imatinib levels were predicted in young male patients and those receiving P-gp/CYP3A4 inducers. These patients had also lower response rates (7% lower 18-months MMR in male, 17% lower 1-year CCyR in young patients, Kaplan-Meier estimates). Time-point independent multivariate regression confirmed a correlation of individual C^min(400mg) with response and adverse events. Possibly due to confounding factors (e.g. dose modifications, patient selection bias), the relationship seemed however flatter than previously reported from prospective controlled studies. Nonetheless, these observational results strongly suggest that a subgroup of patients could benefit from early dosage optimization assisted by TDM, because of lower imatinib concentrations and lower response rates.

Thy-1 binds to integrin beta(3) on astrocytes and triggers formation of focal contact sites.

BACKGROUND: Thy-1 is an abundant neuronal glycoprotein in mammals. Despite such prevalence, Thy-1 function remains largely obscure in the absence of a defined ligand. Astrocytes, ubiquitous cells of the brain, express a putative Thy-1 ligand that prevents neurite outgrowth. In this paper, a ligand molecule for Thy-1 was identified, and the consequences of Thy-1 binding for astrocyte function were investigated. RESULTS: Thy-1 has been implicated in cell adhesion and, indeed, all known Thy-1 sequences were found to contain an integrin binding, RGD-like sequence. Thy-1 interaction with beta3 integrin on astrocytes was demonstrated in an adhesion assay using a thymoma line (EL-4) expressing high levels of Thy-1. EL-4 cells bound to astrocytes five times more readily than EL-4(-f), control cells lacking Thy-1. Binding was blocked by either anti-Thy-1 or anti-beta3 antibodies, by RGD-related peptides, or by soluble Thy-1-Fc chimeras. However, neither RGE/RLE peptides nor Thy-1(RLE)-Fc fusion protein inhibited the interaction. Immobilized Thy-1-Fc, but not Thy-1(RLE)-Fc fusion protein supported the attachment and spreading of astrocytes in a Mn(2+)-dependent manner. Binding to Thy-1-Fc was inhibited by RGD peptides. Moreover, vitronectin, fibrinogen, denatured collagen (dcollagen), and a kistrin-derived peptide, but not fibronectin, also mediated Mn(2+)-dependent adhesion, suggesting the involvement of beta3 integrin. The addition of Thy-1 to matrix-bound astrocytes induced recruitment of paxillin, vinculin, and focal adhesion kinase (FAK) to focal contacts and increased tyrosine phosphorylation of proteins such as p130(Cas) and FAK. Furthermore, astrocyte binding to immobilized Thy-1-Fc alone was sufficient to promote focal adhesion formation and phosphorylation on tyrosine. CONCLUSIONS: Thy-1 binds to beta3 integrin and triggers tyrosine phosphorylation of focal adhesion proteins in astrocytes, thereby promoting focal adhesion formation, cell attachment, and spreading.

Reduction in the expression of glucose transporter protein GLUT 2 in preneoplastic and neoplastic hepatic lesions and reexpression of GLUT 1 in late stages of hepatocarcinogenesis.

Expression of two important glucose transporter proteins, GLUT 2 (which is the typical glucose transporter in hepatocytes of adult liver) and the erythroid/brain type glucose transporter GLUT 1 (representing the typical glucose transporter in fetal liver parenchyma), was studied immunocytochemically during hepatocarcinogenesis in rats at different time points between 7 and 65 wk after cessation of 7-wk administration of 12 mg/kg of body weight of N-nitrosomorpholine p.o. (stop model). Foci of altered hepatocytes excessively storing glycogen (GSF) and mixed cell foci (MCF) composed of both glycogenotic and glycogen-poor cells were present at all time points studied. Seven wk after withdrawal of the carcinogen, GSF were the predominant type of focus of altered hepatocytes. Morphometrical evaluation of the focal lesions revealed that the number and volume fraction of GSF increased steadily until Wk 65. MCF were rare at 7 wk, increased slightly in number and size until Wk 37, but showed a pronounced elevation in their number and volume fraction from Wk 37 to Wk 65. In both GSF and MCF, GLUT 2 was generally decreased or partially absent at all time points. Consequently, foci of decreased GLUT 2 expression showed a steady increase in number and volume fraction from Wk 7 to Wk 65. GLUT 1 was lacking in GSF but occurred in some MCF from Wk 50 onward. The liver type glucose transporter GLUT 2 was decreased in all adenomas and hepatocellular carcinomas (HCC). In three of seven adenomas and 10 of 12 carcinomas, expression of GLUT 1 was increased compared with normal liver parenchyma. In two cases of adenoid HCC, cells of ductular formations coexpressed GLUT 2 and GLUT 1. In contrast, normal bile ducts, bile duct proliferations, and cystic cholangiomas expressed only GLUT 1. Seven of 12 HCC contained many microvessels intensely stained for GLUT 1, a phenomenon never observed in normal liver. Whenever adenoid tumor formations occurred, GLUT 1-positive microvessels were located in the immediate vicinity of these formations. Only in one HCC were such microvessels found in the absence of adenoid formations. Our studies indicate that a reduction of GLUT 2 expression occurs already in early preneoplastic hepatic foci and is maintained throughout hepatocarcinogenesis, including benign and malignant neoplasms. Reexpression of GLUT 1, however, appears in a few MCF and in the majority of adenomas and carcinomas.

24 Hours in the Life of HIV-1 in a T Cell Line.

HIV-1 infects CD4+ T cells and completes its replication cycle in approximately 24 hours. We employed repeated measurements in a standardized cell system and rigorous mathematical modeling to characterize the emergence of the viral replication intermediates and their impact on the cellular transcriptional response with high temporal resolution. We observed 7,991 (73%) of the 10,958 expressed genes to be modulated in concordance with key steps of viral replication. Fifty-two percent of the overall variability in the host transcriptome was explained by linear regression on the viral life cycle. This profound perturbation of cellular physiology was investigated in the light of several regulatory mechanisms, including transcription factors, miRNAs, host-pathogen interaction, and proviral integration. Key features were validated in primary CD4+ T cells, and with viral constructs using alternative entry strategies. We propose a model of early massive cellular shutdown and progressive upregulation of the cellular machinery to complete the viral life cycle.

Role and regulation of islet-Brain 1 in pancreatic &#946;-cells

Résumé : L'insuline est produite et sécrétée par la cellule ß-pancréatique. Son rôle est de régler le taux de sucre dans le sang. Si ces cellules meurent ou échouent à produire suffisamment de l'insuline, les sujets développent le diabète de type 2 (DT2), une des maladies les plus communes dans les pays développés. L'excès chronique des lipoprotéines LDL oxydés (oxLDL) et/ou des cytokines pro-inflammatoires comme l'interleukine-1ß (IL-1ß) participent au dérèglement et à la mort des cellules ß. Nous avons montré qu'une chute des niveaux d'expression de la protéine nommée «mitogen activated protein kinase 8 interacting protein 1» ou «islet brain 1 (IB 1)» est en partie responsable des effets provoqués par les oxLDL ou IL-1ß. IB1 régule l'expression de l'insuline et la survie cellulaire en inhibant la voie de signalisation « c-jun N-terminal Kinase (JNK)». La réduction des niveaux d'expression d'IB1 provoque l'activation de la voie JNK en réponse aux facteurs environnementaux, et ainsi initie la réduction de l'expression de l'insuline et l'induction du programme de mort cellulaire. Les mimétiques de l'hormone "Glucagon-like peptide 1", tel que l'exendin-4 (ex-4), sont une nouvelle classe d'agents hypoglycémiants utilisés dans le traitement du DT2. Les effets bénéfiques de l'ex-4 sont en partie accomplis en préservant l'expression de l'insuline et la survie des cellules ß contre les stress associés au DT2. La restauration des niveaux d'expression d'IB1 est un des mécanismes par lequel l'ex-4 prodigue son effet sur la cellule. En effet, cette molécule stimule l'activité du promoteur du gène et ainsi compense la réduction du contenu en IB1 causée par le stress. Outre ce rôle anti-apoptotique, dans ce travail de thèse nous avons mis en évidence une autre fonction d'IB1 dans la cellule ß. La réduction de l'activité ou des niveaux d'expression d'IB1 induisent une réduction importante de la sécrétion de l'insuline en réponse au glucose. Le mécanisme par lequel IB1 régule la sécrétion de l'insuline implique à la fois le métabolisme du glucose et éventuellement le transport vésiculaire en contrôlant l'expression de la protéine annexin A2. En résumé, IB 1 est une molécule clé à travers laquelle l'environnement du diabétique pourrait exercer un effet délétère sur la cellule ß. L'amélioration de l'activité d'IB1 et/ou de son expression devrait être considérée dans les approches thérapeutiques futures visant à limiter la perte des cellules ß dans le diabète. Abstract : ß-cells of the pancreatic islets of Langerhans produce and secrete insulin when blood glucose rises. In turn, insulin ensures that plasma glucose concentrations return within a relatively narrow physiological range. If ß-cells die or fail to produce enough insulin, individuals develop one of the most common diseases in Western countries, namely type 2 diabetes (T2D). Chronic excess of oxidized low density lipoproteins (oxLDL) and/or pro-inflammatory cytokines such as interleukin 1-ß (IL-1ß) contribute to decline of ß-cells and thereby are thought to accelerate progression of the disease overtime. We showed that profound reduction in the levels of the mitogen activated protein kinase 8 interacting protein 1 also called islet brain 1 (IB1) causes ß-cell failure accomplished by oxLDL or IL-1 ß. IB1 regulates insulin expression and cell survivals by inhibiting the c-Jun N-terminal Kinase pathway. Diminution in IB 1 levels leads to an increase in activation of the JNK pathway induced by environmental stressors, and thus initiates loss of insulin expression and programmed cell death. The mimetic agents of the glucoincretin glucagon-like peptide 1 such as exendin-4 (ex-4) are new class of hypoglycaemic medicines for treatment of T2D. The beneficial property is in part achieved by preserving insulin expression and ß-cell survival against stressors related to diabetes. Restored levels in IB 1 account for the cytoprotective effect of the ex-4. In fact, the latter molecule .stimulates the promoter activity of the gene and thus compensates loss of IB1 content triggered by stress. Beside of the anti-apoptotic role, an additional leading function for IB 1 in ß-cells was highlighted in this thesis. Impairment in IB1 activity or silencing of the gene in ß-cells revealed a major reduction in insulin secretion elicited by glucose. The mechanisms whereby IB 1 couples glucose to insulin release involve glucose metabolism and potentially, vesicles trafficking by maintaining the levels of annexin A2. IB 1 is therefore a key molecule through which environmental factors related to diabetes may exert harmful effects on ß-cells. Improvement in IB 1 activity and/or expression should be considered as a target for therapeutic purpose.

Improvement in secondary hyperparathyroidism due to drug adherence monitoring in dialysis patients.

BACKGROUND: Poor medication adherence is a frequent cause of treatment failure but is difficult to diagnose. In this study we have evaluated the impact of measuring adherence to cinacalcet-HCl and phosphate binders in dialysis patients with uncontrolled secondary hyperparathyroidism. METHODS: 7 chronic dialysis patients with iPTH-levels >= 300 pg/ml despite treatment with >= 60 mg cinacalcet-HCl were included. Medication adherence was measured using the "Medication Events Monitoring System" during 3 months, followed by another 3-month period without monitoring. The adherence results were monthly discussed with the patients, as well as strategies to improve them. RESULTS: During monitoring, the percentage of prescribed doses taken was higher for cinacalcet-HCl (87.4%) and sevelamer (86.3%) than for calcium acetate (76.1%), as was the taking adherence (81.9% vs. 57.3% vs. 49.1%) but not the percentage of drug holidays (12.3% vs. 4.5% vs. 3.6%). Mean PO4 levels (from 2.24 +/- 0.6 mmol/l to 1.73 +/- 0.41 mmol/l; p = 0.14) and Ca++ x PO4 product (4.73 +/- 1.43 to 3.41 +/- 1.04 mmol2/l2; p = 0.12) improved and iPTH-level improved significantly from 916 +/- 618 pg/ml to 442 +/- 326 pg/ml (p = 0.04), without any change in medication. However, as drug monitoring was interrupted, all laboratory parameters worsened again. CONCLUSIONS: Assessment of drug adherence helped to document episodes of non-compliance and helped to avoid seemingly necessary dose increases.