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1.
Z Rheumatol ; 83(2): 87-97, 2024 Mar.
Article in German | MEDLINE | ID: mdl-37644129

ABSTRACT

Patients with inflammatory rheumatic diseases have a higher risk of infections in comparison to the general population. For this patient group, in addition to cardiovascular diseases, infections play an important role with respect to morbidity and mortality. Even if it is difficult to make concrete statements with respect to individual diseases, it can be assumed that there is a lower risk of infections in inflammatory joint diseases in comparison to connective tissue diseases and vasculitides. The increased risk of infections is determined by multiple factors, whereby the underlying factors are classified into three main categories: patient-related factors (age, comorbidities, lifestyle), disease-related factors (immunological dysfunction as part of the disease pathophysiology) and drug-related factors (type and dosage of the immunosuppression and/or immunomodulation). An improved understanding of the complexity of these associations enables the optimization of treatment and disease control taking the individual risk factors into account, with the aim of a significant reduction in the risk of infections.


Subject(s)
Rheumatic Diseases , Rheumatic Fever , Humans , Rheumatic Diseases/epidemiology , Rheumatic Fever/epidemiology , Comorbidity , Immunosuppression Therapy , Immunocompetence
2.
J Autoimmun ; 133: 102918, 2022 12.
Article in English | MEDLINE | ID: mdl-36228431

ABSTRACT

Systemic vaccination against SARS-CoV-2 elicited high titers of specific antibodies in the blood and in the oral cavity. Preexisting autoimmune diseases, such as rheumatoid arthritis, and biological treatments, like B cell depletion, are known to exhibit higher risk of severe COVID-19 manifestation and increased frequency of breakthrough infections after vaccination. We hypothesized that such increased risk is associated with an aberrant induction of secreted antibodies in the oral cavity. Here we evaluated the levels of secreted antibodies in the oral cavity against the SARS-CoV-2 Spike protein during the course of vaccination in RA patients with or without B cell depletion. We found that total salivary IgG levels were correlated with number of B cells in the blood. Anti-Spike IgG responses 7 days after second vaccination were induced in the oral cavity of all healthy individuals, while only 6 out 23 RA patients exhibited anti-Spike IgG in their saliva regardless of B cell depleting therapy. Importantly, both salivary and serologic anti-Spike IgG and IgA responses towards WT and omicron Spike variants were efficiently induced by third vaccination in RA patients with or without B cell depletion to the levels that were similar to healthy individuals. Altogether, these data advocate for the necessity of three dose vaccination for RA patients to mount anti-Spike antibody responses at the mucosal surfaces and annotate the reduction of secreted salivary IgG by B cell depletion.


Subject(s)
Arthritis, Rheumatoid , COVID-19 , Humans , COVID-19 Vaccines , Antibody Formation , SARS-CoV-2 , COVID-19/prevention & control , Antibodies, Viral , Arthritis, Rheumatoid/drug therapy , Immunoglobulin G
3.
Z Rheumatol ; 79(3): 241-254, 2020 Apr.
Article in German | MEDLINE | ID: mdl-32219519

ABSTRACT

BACKGROUND: Cytokines and associated intracellular signal cascades play a major role in the pathogenesis of autoimmune diseases. Janus kinases (JAK) are part of these intracellular signal transduction processes. A relatively new drug group of targeted synthetic disease-modifying antirheumatic drugs (tsDMARD) are JAK inhibitors (JAKi) and are a promising treatment approach for autoimmune diseases. EFFICACY: Hitherto, three JAKis, Tofacitinib, Baricitinib and Upadacitinib, have been approved for treatment of Rheumatoid Arthritis (RA) in the USA, Switzerland and the EU. Filgotinib, another JAKi, also showed promising results in the treatment of RA. Furthermore, tofacitinib received approval for the treatment of ulcerative colitis and psoriatic arthritis. In addition to the JAKis already mentioned, several other JAKis, e.g. filgotinib and peficitinib, are being and were investigated in various studies on indications, such as atopic dermatitis, ankylosing spondylitis and systemic lupus erythematosus. SAFETY: Being immunosuppressants, JAKis show an elevated incidence of severe infections, comparable to biologics. The increased reactivation of varicella zoster virus is especially noteworthy. Under JAKi treatment cytopenia is also more frequent. Lymphopenia under JAKi treatment is of particular clinical relevance because of its association with an increase in the number of severe infections. Furthermore, an elevated risk of thromboembolic events, particularly pulmonary embolism has been noted. The risks concerning metabolic alterations and the occurrence of malignant neoplasms are comparable to those under treatment with biologics.


Subject(s)
Antirheumatic Agents , Arthritis, Psoriatic , Arthritis, Rheumatoid , Janus Kinase Inhibitors , Antirheumatic Agents/adverse effects , Antirheumatic Agents/therapeutic use , Arthritis, Psoriatic/drug therapy , Arthritis, Rheumatoid/drug therapy , Biosimilar Pharmaceuticals/therapeutic use , Humans , Janus Kinase 3/antagonists & inhibitors , Janus Kinase Inhibitors/adverse effects , Janus Kinase Inhibitors/therapeutic use , Janus Kinases/antagonists & inhibitors
4.
Curr Med Res Opin ; 32(8): 1425-34, 2016 08.
Article in English | MEDLINE | ID: mdl-27126277

ABSTRACT

Many patients with type 2 diabetes mellitus (T2DM) require insulin therapy. If basal insulin fails to achieve glycemic control, insulin intensification is one possible treatment intensification strategy. We summarized clinical data from randomized clinical trials designed to compare the efficacy and safety of basal-bolus and premixed insulin intensification regimens. We defined a between-group difference of ≥0.3% in end-of-study glycated hemoglobin (HbA1c) as clinically meaningful. A PubMed database search supplemented by author-identified papers yielded 15 trials which met selection criteria: randomized design, patients with T2DM receiving basal-bolus (bolus injection ≤3 times/day) vs. premixed (≤3 injections/day) insulin regimens, primary/major endpoint(s) HbA1c- and/or hypoglycemia-related, and trial duration ≥12 weeks. Glycemic control improved with both basal-bolus and premixed insulin regimens with - in most cases - acceptable levels of weight gain and hypoglycemia. A clinically meaningful difference between regimens in glycemic control was recorded in only four comparisons, all of which favored basal-bolus therapy. The incidence of hypoglycemia was significantly different between regimens in only three comparisons, one of which favored premixed insulin and two basal-bolus therapy. Of the four trials that reported a significant difference between regimens in bodyweight change, two favored basal-bolus therapy and two favored premixed insulin. Thus, on a population level, neither basal-bolus therapy nor premixed insulin showed a consistent advantage in terms of glycemic control, hypoglycemic risk, or bodyweight gain. It is therefore recommended that clinicians should adopt an individualized approach to insulin intensification - taking into account the benefits and risks of each treatment approach and the attitude and preferences of each patient - in the knowledge that both basal-bolus and premixed regimens may be successful.


Subject(s)
Diabetes Mellitus, Type 2/drug therapy , Hypoglycemic Agents/therapeutic use , Insulin/therapeutic use , Blood Glucose/analysis , Diabetes Mellitus, Type 2/blood , Glycated Hemoglobin/analysis , Humans , Hypoglycemia/etiology , Insulin/administration & dosage , Precision Medicine , Weight Gain
5.
Article in English | MEDLINE | ID: mdl-26172771

ABSTRACT

The subject of the experimental research supported with numerical simulations presented in this paper is an analog electrical circuit representing the ring of unidirectionally coupled single-well Duffing oscillators. The research is concentrated on the existence of the stable three-frequency quasiperiodic attractor in this system. It is shown that such solution can be robustly stable in a wide range of parameters of the system under consideration in spite of a parameter mismatch which is unavoidable during experiment.

6.
Chaos ; 25(3): 033113, 2015 Mar.
Article in English | MEDLINE | ID: mdl-25833435

ABSTRACT

We study the coupling induced destabilization in an array of identical oscillators coupled in a ring structure where the number of oscillators in the ring is large. The coupling structure includes different types of interactions with several next neighbors. We derive an amplitude equation of Ginzburg-Landau type, which describes the destabilization of a uniform stationary state and close-by solutions in the limit of a large number of nodes. Studying numerically an example of unidirectionally coupled Duffing oscillators, we observe a coupling induced transition to collective spatio-temporal chaos, which can be understood using the derived amplitude equations.


Subject(s)
Algorithms , Feedback , Models, Theoretical , Nonlinear Dynamics , Oscillometry/methods , Spatio-Temporal Analysis , Computer Simulation
7.
Cell Death Dis ; 4: e859, 2013 Oct 17.
Article in English | MEDLINE | ID: mdl-24136223

ABSTRACT

The p90 ribosomal S6 kinase (RSK) family is a group of highly conserved Ser/Thr kinases that promote cell proliferation, growth, motility and survival. As they are almost exclusively activated downstream of extracellular signal-regulated kinases 1 and 2 (ERK1/2), therapeutic intervention by RSK inhibition is less likely to produce such severe side effects as those observed following inhibition of the upstream master regulators Raf, MEK and ERK1/2. Here, we report that BI-D1870, a potent small molecule inhibitor of RSKs, induces apoptosis, although preferentially, in a p21-deficient background. On the other hand, BI-D1870 also induces a strong transcription- and p53-independent accumulation of p21 protein and protects cells from gamma irradiation (γIR)-induced apoptosis, driving them into senescence even in the absence of γIR. Although we identified p21 in in vitro kinase assays as a novel RSK substrate that specifically becomes phosphorylated by RSK1-3 at Ser116 and Ser146, RNA-interference, overexpression and co-immunoprecipitation studies as well as the use of SL0101, another specific RSK inhibitor, revealed that BI-D1870 mediates p21 accumulation via a yet unknown pathway that, besides its off-site targets polo-like kinase-1 and AuroraB, also does also not involve RSKs. Thus, this novel off-target effect of BI-D1870 should be taken into serious consideration in future studies investigating the role of RSKs in cellular signaling and tumorigenesis.


Subject(s)
Apoptosis/radiation effects , Cellular Senescence/drug effects , Cyclin-Dependent Kinase Inhibitor p21/metabolism , Gamma Rays , Pteridines/pharmacology , Ribosomal Protein S6 Kinases, 90-kDa/antagonists & inhibitors , Tumor Suppressor Protein p53/metabolism , Apoptosis/drug effects , Aurora Kinases/metabolism , Benzopyrans/pharmacology , Cell Cycle Proteins/metabolism , Cellular Senescence/radiation effects , Cyclin-Dependent Kinase Inhibitor p21/pharmacology , Gene Knockdown Techniques , HCT116 Cells , Humans , Isoenzymes/metabolism , Monosaccharides/pharmacology , Phosphorylation/drug effects , Phosphorylation/radiation effects , Phosphoserine/metabolism , Protein Kinase Inhibitors/pharmacology , Protein Serine-Threonine Kinases/metabolism , Proto-Oncogene Proteins/metabolism , Ribosomal Protein S6 Kinases, 90-kDa/metabolism , Stress, Physiological/drug effects , Stress, Physiological/radiation effects , Substrate Specificity/drug effects , Substrate Specificity/radiation effects , Transcription, Genetic/drug effects , Transcription, Genetic/radiation effects , Polo-Like Kinase 1
8.
Toxicol In Vitro ; 27(7): 2023-30, 2013 Oct.
Article in English | MEDLINE | ID: mdl-23916975

ABSTRACT

In this study, we established cell culture conditions for primary equine hepatocytes allowing cytochrome P450 enzyme (CYP) induction experiments. Hepatocytes were isolated after a modified method of Bakala et al. (2003) and cultivated on collagen I coated plates. Three different media were compared for their influence on morphology, viability and CYP activity of the hepatocytes. CYP activity was evaluated with the fluorescent substrate 7-benzyloxy-4-trifluoromethylcoumarin. Induction experiments were carried out with rifampicin, dexamethasone or phenobarbital. Concentration-response curves for induction with rifampicin were created. Williams' medium E showed the best results on morphology and viability of the hepatocytes and was therefore used for the following induction experiments. Cells cultured in Dulbecco's Modified Eagle Medium were not inducible. Incubation with rifampicin increased the CYP activity in two different hepatocyte preparations in a dose dependent manner (EC50=1.20 µM and 6.06 µM; Emax=4.1- and 3.4-fold induction). No increase in CYP activity was detected after incubation with dexamethasone or phenobarbital. The hepatocyte culture conditions established in this study proved to be valuable for investigation of the induction of equine CYPs. In further studies, other equine drugs can be evaluated for CYP induction with this in vitro system.


Subject(s)
Cytochrome P-450 Enzyme System/drug effects , Drug Evaluation, Preclinical/veterinary , Hepatocytes/drug effects , Veterinary Drugs/pharmacology , Animals , Anti-Inflammatory Agents/adverse effects , Anti-Inflammatory Agents/pharmacology , Antibiotics, Antitubercular/adverse effects , Antibiotics, Antitubercular/pharmacology , Cell Survival/drug effects , Cells, Cultured , Coumarins/metabolism , Culture Media, Serum-Free/metabolism , Cytochrome P-450 Enzyme System/biosynthesis , Cytochrome P-450 Enzyme System/metabolism , Dexamethasone/adverse effects , Dexamethasone/pharmacology , Enzyme Induction/drug effects , Hepatocytes/cytology , Hepatocytes/metabolism , Horses , Hypnotics and Sedatives/adverse effects , Hypnotics and Sedatives/pharmacology , Immunohistochemistry/veterinary , Indicators and Reagents/metabolism , Kinetics , Phenobarbital/adverse effects , Phenobarbital/pharmacology , Rifampin/adverse effects , Rifampin/pharmacology , Veterinary Drugs/adverse effects
9.
Int J Clin Pract ; 66(11): 1033-41, 2012 Nov.
Article in English | MEDLINE | ID: mdl-23067027

ABSTRACT

AIMS: The choice of insulin at initiation in type 2 diabetes remains controversial. The aim of this study was to assess the occurrence of self-reported severe hypoglycaemia associated with premixed insulin analogues in routine clinical care. METHODS: A 12-month, prospective, observational, multicentre study in patients starting a commonly prescribed premixed insulin analogue (either insulin lispro 25/75 or biphasic insulin aspart 30/70, twice daily) after suboptimal glycaemic control on oral antidiabetic agents. Treatment decisions were made solely in the course of usual practice. RESULTS: Study follow-up was completed by 991 (85.5%) of the 1150 patients enrolled. At baseline, mean (SD) age was 57.9 (10.1) years; mean diabetes duration was 9.2 (5.9) years; mean haemoglobin A(1c) (HbA(1c)) was 9.9 (1.8) % and the rate of severe hypoglycaemia was 0.03 episode/patient-year. At 12 months, the rate of severe hypoglycaemia was 0.04 episode/patient-year (95% CI 0.023, 0.055 episode/patient-year) and mean insulin dose was 41.5 (19.4) units. Changes from baseline to 12 months for mean fasting plasma glucose and HbA(1c) were -5.1 mmol/l and -2.5%, respectively. CONCLUSIONS: After initiation of premixed insulin analogues in patients with type 2 diabetes in real-world settings, the incidence of severe hypoglycaemia was lower than expected from previously reported studies.


Subject(s)
Diabetes Mellitus, Type 2/drug therapy , Hypoglycemia/chemically induced , Hypoglycemic Agents/adverse effects , Insulin/analogs & derivatives , Ambulatory Care , Blood Glucose/metabolism , Body Mass Index , Body Weight , Diabetes Mellitus, Type 2/blood , Fasting/blood , Female , Glycated Hemoglobin/metabolism , Humans , Insulin/adverse effects , Male , Middle Aged , Prospective Studies
10.
Clin Endocrinol (Oxf) ; 75(5): 636-41, 2011 Nov.
Article in English | MEDLINE | ID: mdl-21564155

ABSTRACT

OBJECTIVE: Wolfram syndrome is a rare form of diabetes mellitus associated with optic atrophy and disorders of different organs (e.g. diabetes insipidus, hearing loss, ataxia, anaemia and many others). This syndrome is caused by recessive mutations in the wolframin gene (WFS1) localized on chromosome 4p16·1. The aim of this study was to identify the causative mutations in WFS1 in a group of Polish patients with suspected Wolfram syndrome. PATIENTS AND MEASUREMENTS: Nine patients with clinical symptoms consistent with Wolfram syndrome (at least diabetes mellitus and optic atrophy) and 22 first-degree relatives were examined. The molecular analysis was carried out by direct sequencing of the exons, the exon-intron junctions, and the 5' and 3' untranslated regions of WFS1. RESULTS: Nine different mutations in WFS1 (five of them novel) were identified in the nine patients. Six patients were homozygous for the following mutations: V412fs, S443R, W539X, V659fs. They developed diabetes at a mean age of 5·2 years. Three patients were compound-heterozygous for the following mutations: S167fs, Q392X, Y513fs, W648X, V779G. They developed diabetes at a mean age of 6·5 years. CONCLUSIONS: Mean age of diagnosis of diabetes among the Polish patients was typical for Wolfram syndrome; however, compound-heterozygous patients were slightly older at diabetes onset.


Subject(s)
Genetic Association Studies/methods , Mutation/genetics , Wolfram Syndrome/genetics , Adolescent , Female , Humans , Male , Membrane Proteins/genetics , Multiplex Polymerase Chain Reaction , Poland , Polymerase Chain Reaction , Polymorphism, Restriction Fragment Length/genetics , White People/genetics , Young Adult
11.
Chaos ; 20(1): 013111, 2010 Mar.
Article in English | MEDLINE | ID: mdl-20370266

ABSTRACT

We study the dynamics of a ring of unidirectionally coupled autonomous Duffing oscillators. Starting from a situation where the individual oscillator without coupling has only trivial equilibrium dynamics, the coupling induces complicated transitions to periodic, quasiperiodic, chaotic, and hyperchaotic behavior. We study these transitions in detail for small and large numbers of oscillators. Particular attention is paid to the role of unstable periodic solutions for the appearance of chaotic rotating waves, spatiotemporal structures, and the Eckhaus effect for a large number of oscillators. Our analytical and numerical results are confirmed by a simple experiment based on the electronic implementation of coupled Duffing oscillators.


Subject(s)
Biophysics/methods , Nonlinear Dynamics , Oscillometry/methods , Algorithms , Electronics , Models, Statistical , Models, Theoretical , Time Factors
12.
Phys Rev E Stat Nonlin Soft Matter Phys ; 78(1 Pt 2): 017203, 2008 Jul.
Article in English | MEDLINE | ID: mdl-18764084

ABSTRACT

Synchronization thresholds of an array of nondiagonally coupled oscillators are investigated. We present experimental results which show the existence of ragged synchronizability, i.e., the existence of multiple disconnected synchronization regions in the coupling parameter space. This phenomenon has been observed in an electronic implementation of an array of nondiagonally coupled van der Pol's oscillators. Numerical simulations show good agreement with the experimental observations.

13.
Phys Rev E Stat Nonlin Soft Matter Phys ; 77(4 Pt 2): 048201; discussion 048202, 2008 Apr.
Article in English | MEDLINE | ID: mdl-18517759

ABSTRACT

We have verified some results of Nana and Woafo [Phys. Rev. E 74, 046213 (2006)] in the area of the complete synchronization. We have found that the motion of the van der Pol network is quasiperiodic, not chaotic as the authors have written.

14.
Exp Clin Endocrinol Diabetes ; 115(5): 317-21, 2007 May.
Article in English | MEDLINE | ID: mdl-17516295

ABSTRACT

HYPOTHESIS: A gene polymorphism associated with accelerated beta-cell failure may lead to a more rapid development of long-term complications of type 2 diabetes (T2DM) due to a worse metabolic control of the disease. AIM OF THE STUDY: Evaluation of an association between the intronic C49620T (exon 16 -3c-->t) polymorphism in the ABCC8 (SUR1) gene and beta-cell function, as well as the prevalence of long-term diabetic complications in obese patients with long-lasting type 2 diabetes. METHODS: Two hundred and fifteen obese patients with at least a 10-year history of T2DM were thoroughly characterized clinically. In all the patients the intravenous glucagon test was performed and the C49620T ABCC8 polymorphism was assessed. Subgroups of patients, classified either according to genotype or to allele carriage, were compared. RESULTS: No difference was found between the groups in variables describing beta-cell function and the prevalence of chronic diabetic complications, with the exception of a significantly lower incidence of brain stroke in CC homozygotes than in patients carrying T allele (CT+TT). Body mass index was higher in patients carrying C allele than in TT homozygotes. HDL-cholesterol was higher in CT heterozygous than in homozygous CC or TT patients. CONCLUSIONS: There is no association between the ABCC8 polymorphism gene and the beta-cell function or the prevalence of chronic diabetic complications in obese patients with long-term T2DM, except for brain stroke. The results might suggest that the homozygous CC subjects are at lower risk of the complication, but additional studies are warranted to test this finding.


Subject(s)
ATP-Binding Cassette Transporters/genetics , Diabetes Mellitus, Type 2/complications , Insulin-Secreting Cells/physiology , Obesity/complications , Polymorphism, Single Nucleotide , Potassium Channels, Inwardly Rectifying/genetics , Potassium Channels/genetics , Receptors, Drug/genetics , Aged , Chronic Disease , Diabetes Complications/epidemiology , Diabetes Mellitus, Type 2/genetics , Diabetes Mellitus, Type 2/physiopathology , Female , Glucagon/administration & dosage , Humans , Injections, Intravenous , Insulin Resistance/genetics , Male , Middle Aged , Obesity/genetics , Obesity/physiopathology , Prevalence , Stroke/epidemiology , Stroke/genetics , Sulfonylurea Receptors , Time Factors
15.
J Hum Hypertens ; 20(9): 684-92, 2006 Sep.
Article in English | MEDLINE | ID: mdl-16625233

ABSTRACT

The aim of the study was to examine an association between the Pro12Ala polymorphism of the peroxisome proliferator-activated receptor (PPAR)-gamma2 gene and blood pressure values assessed by 24-h ambulatory blood pressure monitoring (ABPM) in obese patients with long-lasting type II diabetes. Two hundred and fourteen obese patients (95 men and 119 women) with above 10-year history of type II diabetes were recruited for the study. In all the patients, ABPM was performed and other parameters, including age, body mass index (BMI), waist/hip ratio (WHR), haemoglobin A1c (HbA(1c)), serum lipids and creatinine were also evaluated. The Pro12Ala polymorphism was analysed by polymerase chain reaction-restriction fragment length polymorphism. Two subgroups of patients were compared: (a) Pro/Pro: homozygotic Pro/Pro (n=154) and (b) Ala: Ala allele carriers (Ala/Ala+Ala/Pro) (n=60). The studied groups were not different when age, BMI, WHR, HbA(1c), lipids, creatinine and frequency of hypertension were compared. A similar ratio of patients from both groups were treated with angiotensin-converting enzyme inhibitors, calcium channel blockers, diuretics, beta-blockers and alpha-blockers. A difference was observed in a mean 24-h (Ala: 71.9+/-8.1 vs Pro/Pro: 69.4+/-7.8 mm Hg, P=0.034) and a mean night time (Ala: 67.1+/-7.8 vs Pro/Pro: 64.5+/-8.4 mm Hg, P=0.025) diastolic blood pressure, which was significantly higher in patients with Ala variant. There was also a trend towards a higher mean daytime diastolic blood pressure in this group. It seems that the Pro12Ala variant is associated with an increased mean 24-h diastolic blood pressure in obese diabetic patients. Different reaction for antihypertensive medication depending on a variant of the PPAR-gamma2 gene should also be considered as a possible cause of the presented results.


Subject(s)
Alanine/genetics , Diabetes Mellitus, Type 2/genetics , Diabetes Mellitus, Type 2/physiopathology , Obesity/genetics , Obesity/physiopathology , PPAR gamma/genetics , Proline/genetics , Alleles , Blood Pressure , Body Mass Index , Diabetes Mellitus, Type 2/complications , Female , Humans , Hypertension/complications , Hypertension/genetics , Hypertension/physiopathology , Male , Middle Aged , Obesity/complications , Polymorphism, Genetic/genetics , Time Factors
16.
Hum Mutat ; 21(6): 630-5, 2003 Jun.
Article in English | MEDLINE | ID: mdl-12754710

ABSTRACT

Mulibrey nanism (muscle-liver-brain-eye nanism; MUL) is an autosomal recessively transmitted disease characterized by severe growth delays of prenatal onset caused by mutations in the TRIM37 gene. Recent studies on the subcellular localization revealed that the TRIM37 (KIAA0898) protein is located in peroxisomes. Therefore, MUL has been classified as a new peroxisomal disorder. Up to now, four mutations have been reported, all of which lead to frameshifts and truncated proteins. In this study, mutation screening was performed for the coding region of the TRIM37 gene in a Turkish family by means of RT-PCR and direct cDNA sequencing. We have identified a novel mutation resulting in a frameshift cosegregating within the family. Finally, we report on the presence of novel splice variants observed in lymphoblastoid cells and muscle tissue of normal subjects and patients.


Subject(s)
Dwarfism/genetics , Mutation/genetics , Nuclear Proteins , Peroxisomal Disorders/genetics , Proteins/genetics , RNA Splice Sites/genetics , Base Sequence , DNA Mutational Analysis , Dwarfism/physiopathology , Female , Frameshift Mutation/genetics , Humans , Male , Molecular Sequence Data , Muscles/metabolism , Pedigree , Peroxisomal Disorders/physiopathology , Phenotype , RNA, Messenger/genetics , RNA, Messenger/metabolism , Tripartite Motif Proteins , Turkey , Ubiquitin-Protein Ligases
17.
Eur J Clin Invest ; 27(7): 629-33, 1997 Jul.
Article in English | MEDLINE | ID: mdl-9263752

ABSTRACT

Administration of active vitamin D (calcitriol) improves insulin sensitivity in uraemic patients. These patients have subnormal plasma calcitriol concentrations in parallel with increased intact parathyroid hormone (PTH) concentrations. It is therefore unclear whether the improvement in insulin sensitivity results from a direct effect of calcitriol or from amelioration of secondary hyperparathyroidism. So far, no evidence has been presented that insulin sensitivity is specifically affected by calcitriol in healthy subjects. We investigated the effect of (supra)therapeutic doses of calcitriol on insulin sensitivity in healthy volunteers. In a double-blind parallel group design, 18 healthy male subjects received in random order either placebo or 1.5 micrograms of calcitriol per day by mouth for 7 days. Insulin-mediated glucose uptake, i.e. insulin sensitivity, was assessed using the euglycaemic clamp technique. Mean glucose disposal rate, i.e. M-value, was not significantly affected by placebo or calcitriol treatment (placebo: 7.1 +/- 1.3 mg kg-1 min-1 before and 7.2 +/- 1.5 mg kg-1 min-1 after treatment; calcitriol 7.0 +/- 1.4 mg kg-1 min-1 and 7.2 +/- 1.4 mg kg-1 min-1). There were no significant changes in mean plasma glucose, insulin, phosphate, bicarbonate and ionized calcium concentrations after administration of placebo or calcitriol. Furthermore, platelet intracellular calcium concentration (assessed by fluorescence spectroscopy) and mean arterial blood pressure (24 h ambulatory measurement) did not change with placebo and calcitriol treatment. On the other hand, mean intact PTH concentration decreased significantly (P < 0.01) with calcitriol treatment, but not with placebo. In addition, mean 24 h urinary calcium excretion increased significantly (P < 0.05) with calcitriol administration but was unchanged with placebo. Administration of (supra)physiological doses of calcitriol has no effect on insulin sensitivity in healthy subjects, despite a significant decrease in PTH concentrations. These observations are compatible with the notion that the effect of calcitriol on insulin sensitivity is present only in uraemic calcitriol-depleted patients.


Subject(s)
Blood Glucose/metabolism , Calcitriol/pharmacology , Insulin/pharmacology , Administration, Oral , Adult , Calcitriol/administration & dosage , Double-Blind Method , Glucose Clamp Technique , Humans , Male
18.
Am J Physiol ; 272(6 Pt 1): C1836-43, 1997 Jun.
Article in English | MEDLINE | ID: mdl-9227412

ABSTRACT

We recently reported that neutral endopeptidase (NEP) expression on renal vascular smooth muscle cells (VSMC) was downregulated in the presence of serum. Here we examine the role of epidermal growth factor (EGF) and transforming growth factor-beta 1 (TGF-beta) in this downregulation and the consequences of the changes in NEP activity on their mitogenic effects. EGF inhibited NEP activity, whereas TGF-beta was stimulatory. Expression of the enzyme was studied by measuring the binding of [125I]RB-104, a specific NEP inhibitor, and the fluorescence intensity of NEP-labeled cells. Both parameters were decreased by EGF and were increased by TGF-beta. NEP mRNA expression in EGF-treated cells was reduced after 48 h. In contrast, it was increased in TGF-beta-treated cells. Interestingly, NEP inhibition influenced the mitogenic effect of EGF. Indeed, thiorphan, an NEP inhibitor, and an anti-NEP antibody decreased EGF-dependent [3H]thymidine incorporation and cell proliferation by approximately 50%. TGF-beta had no effect on VSMC growth. These results indicate that EGF but not TGF-beta participates in the downregulatory potency of serum on NEP expression in VSMC. They also demonstrate that the full effect of EGF on VSMC proliferation depends on intact NEP activity.


Subject(s)
Epidermal Growth Factor/pharmacology , Gene Expression Regulation, Enzymologic/drug effects , Kidney Cortex/blood supply , Muscle, Smooth, Vascular/enzymology , Neprilysin/biosynthesis , Transforming Growth Factor beta/pharmacology , Animals , Cell Division/drug effects , Cell Membrane/enzymology , Cells, Cultured , Flow Cytometry , Iodobenzenes/metabolism , Kinetics , Male , Muscle, Smooth, Vascular/cytology , Muscle, Smooth, Vascular/drug effects , Protease Inhibitors/metabolism , Rabbits , Time Factors , Transcription, Genetic/drug effects , gamma-Aminobutyric Acid/analogs & derivatives , gamma-Aminobutyric Acid/metabolism
19.
Nephrol Dial Transplant ; 12(5): 933-8, 1997 May.
Article in English | MEDLINE | ID: mdl-9175045

ABSTRACT

BACKGROUND: Acute administration of parathyroid hormone (PTH) causes vasodilation and blood pressure decrease in experimental animals. This effect contrasts with the putative role of secondary hyperparathyroidism in the pathogenesis of hypertension of patients with renal failure. Uraemia is characterized by insulin resistance and hyperinsulinaemia. We therefore investigated whether subacute administration of physiological doses of human 1,34-PTH affects blood pressure under conditions of controlled insulin levels (euglycaemic clamp technique) in humans. METHODS: In a double-blind cross-over design 10 healthy male subjects received, on two occasions, in random order, for 2 h, either a sham infusion or an infusion of 200 units of 1,34-PTH. RESULTS: Mean ionized calcium concentration increased significantly (P < 0.01) within the normal range during euglycaemic hyperinsulinaemia, both with sham infusion (from 1.25 +/- 0.04 to 1.29 +/- 0.02 mmol/l) and with infusion of 1,34-PTH, but the increase was more marked with 1,34-PTH administration (from 1.26 +/- 0.05 to 1.33 +/- 0.07). In addition, mean platelet intracellular calcium concentration (by fluorescence spectroscopy) was unchanged with sham infusion (49.9 +/- 4.1 versus 50.3 +/- 5.0 nmol), but increased significantly (P < 0.05; paired t-test) after 1,34-PTH infusion (from 49.8 +/- 5.0 to 52.8 +/- 5.8). The infusion of 1,34-PTH resulted in a significant (P < 0.01) increase in mean MAP (from 84 +/- 5 to 88 +/- 5 mmHg) as compared with sham infusion (85 +/- 4 versus 86 +/- 4). The intra-individual changes in intracellular calcium concentration (delta[Ca2+]i) were significantly correlated to the changes in mean MAP (delta MAP) (r = 0.87, P < 0.001). In contrast to blood pressure, insulin sensitivity was not affected by 1,34-PTH infusion (M-value: 7.2 +/- 1.6 mg/kg per min) as compared with sham infusion (7.3 +/- 1.4). CONCLUSION: Subacute administration of physiological doses of parathyroid hormone under hyperinsulinaemic conditions significantly affects intracellular calcium and blood pressure in healthy subjects, but does not affect the action of insulin.


Subject(s)
Blood Pressure/drug effects , Blood Pressure/physiology , Parathyroid Hormone/physiology , Teriparatide/administration & dosage , Adult , Animals , Blood Glucose/metabolism , Blood Platelets/drug effects , Blood Platelets/metabolism , Calcium/blood , Cross-Over Studies , Double-Blind Method , Humans , Hypertension/blood , Hypertension/etiology , Hypertension/physiopathology , Infusions, Intravenous , Insulin/blood , Insulin Resistance , Male
20.
Kidney Int ; 50(4): 1321-6, 1996 Oct.
Article in English | MEDLINE | ID: mdl-8887294

ABSTRACT

In patients with diabetic nephropathy blood pressure increases progressively before the conventional threshold of normal blood pressure (140/90 mm Hg) is transgressed. In patients with glomerulonephritis, no information on this point is available. To clarify this issue we sequentially examined 20 untreated patients with biopsy-proven primary chronic glomerulonephritis (GN) who had casual blood pressure below 140/90 mm Hg and normal GFR by inulin clearance. Patients were compared with normotensive healthy controls who were matched for BMI, gender and age. We measured ambulatory 24-hour blood pressure (SpaceLab system), echocardiography (ASE criteria, Acuson 128 XP 10), CIn and CPAH, urinary Na excretion, PRA and insulin concentration. In patients with GN, the median 24 hour (P < 0.0005), daytime (P < 0.001) and nocturnal sleeping time (P < 0.0001) MAP values were significantly higher than in matched controls (daytime, mean 97 mm Hg, 85 to 106 GN vs. 89 controls range 82 to 102; nocturnal sleeping time, mean 80.3 mm Hg, 71 to 89.5 GN vs. 73 controls, range 63 to 84). Echocardiographic examination showed significantly greater posterior wall thickness (P < 0.01) and ventricular septal thickness (P < 0.003). In addition the early diastolic to late diastolic (E/A) ratio of mitral valve peak inflow velocity was significantly (P < 0.0008) lower in patients. The data point to left ventricular wall thickening accompanied by LV diastolic malfunction. The study documents elevated ambulatory blood pressure in patients with primary chronic glomerulonephritis despite normal body weight and normal GFR. This is associated with evidence of target organ damage in the heart. The findings suggest that in patients with glomerulonephritis blood pressure increases initially within the normotensive range. This observation in conjunction with evidence of early target organ changes provides an argument for early antihypertensive intervention, but controlled trials to test efficacy and safety of this proposal are necessary.


Subject(s)
Blood Pressure , Glomerulonephritis, IGA/physiopathology , Ventricular Dysfunction, Left/complications , Adult , Biopsy , Circadian Rhythm , Echocardiography , Female , Glomerulonephritis, IGA/complications , Humans , Inulin/metabolism , Male , Middle Aged , p-Aminohippuric Acid/metabolism
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