Transjugular intrahepatic portosystemic shunt: impact on systemic hemodynamics and renal and cardiac function in patients with cirrhosis.

Transjugular intrahepatic portosystemic shunt (TIPS) alleviates portal hypertension and possibly increases central blood volume (CBV). Moreover, renal function often improves; however, its effects on cardiac function are unclear. The aims of our study were to examine the effects of TIPS on hemodynamics and renal and cardiac function in patients with cirrhosis. In 25 cirrhotic patients, we analyzed systemic, cardiac, and splanchnic hemodynamics by catheterization of the liver veins and right heart chambers before and 1 wk after TIPS. Additionally, we measured renal and cardiac markers and performed advanced echocardiography before, 1 wk after, and 4 mo after TIPS. CBV increased significantly after TIPS (+4.6%, P < 0.05). Cardiac output (CO) increased (+15.3%, P < 0.005) due to an increase in stroke volume (SV) (+11.1%, P < 0.005), whereas heart rate (HR) was initially unchanged. Cardiopulmonary pressures increased after TIPS, whereas copeptin, a marker of vasopressin, decreased (-18%, P < 0.005) and proatrial natriuretic peptide increased (+52%, P < 0.0005) 1 wk after TIPS and returned to baseline 4 mo after TIPS. Plasma neutrophil gelatinase-associated lipocalin, renin, aldosterone, and serum creatinine decreased after TIPS (-36%, P < 0.005; -65%, P < 0.05; -90%, P < 0.005; and -13%, P < 0.005, respectively). Echocardiography revealed subtle changes in cardiac function after TIPS, although these were within the normal range. TIPS increases CBV by increasing CO and SV, whereas HR is initially unaltered. These results indicate an inability to increase the heart rate in response to a hemodynamic challenge that only partially increases CBV after TIPS. These changes, however, are sufficient for improving renal function. NEW & NOTEWORTHY For the first time, we have combined advanced techniques to study the integrated effects of transjugular intrahepatic portosystemic shunt (TIPS) in cirrhosis. We showed that TIPS increases central blood volume (CBV) through improved cardiac inotropy. Advanced echocardiography demonstrated that myocardial function was unaffected by the dramatic increase in preload after TIPS. Finally, renal function improved due to the increase in CBV. Recognition of these physiological changes significantly contributes to our clinical understanding of TIPS.

Evaluation of NGAL TestTM on Cobas 6000.

BACKGROUND: Neutrophil Gelatinase-Associated Lipocalin (NGAL) is a promising biomarker for acute kidney injury (AKI). Our objectives were to evaluate the NGAL Test(TM) from Bioporto for both urine NGAL and plasma NGAL on the Cobas 6000 c501 (Roche Diagnostics, Rotkreuz, Switzerland) with matched measurements run on Hitachi 917, the method's linearity on the Cobas 6000 in urine, EDTA and Lithium-Heparin (Li-Hep), the influence of using EDTA or Li-Hep tubes and, finally, the impact of freezing and thawing on the sample. METHODS: Forty matched samples of Li-Hep and EDTA plasma and 40 urine samples were analyzed for method, anticoagulant, and freeze-thaw comparisons. Linearity was assessed using high NGAL samples diluted in urine, EDTA, and Li-Hep plasma. Commercial internal controls were used for the imprecision study. RESULTS: The Cobas 6000 measured identically with the Hitachi 917, however, not in EDTA plasma (Median Difference = 17.50 µg/L, p < 0.0001). Freeze-thaw process reduced NGAL ((EDTA: Mean Difference = = 15.13 µg/L, p = 0.0014)(Li-Hep: Median Difference = = 6.5 µg/L, p = 0.0129)). NGAL results were higher in Li-Hep plasma than in EDTA plasma ((Non-thawed: Median Difference = = 14.5 µg/L, p < 0.0001), (Thawed: Median Difference = = 21.5 µg/L, p = 0.0003)). Linearity agreements were observed in all three specimens. Imprecision (CV%) was below 3%. CONCLUSION: The NGAL Test(TM) can be applied on the Cobas 6000 with acceptable performance, although the Cobas 6000 measured higher than the Hitachi 917 in EDTA plasma. Though clinically insignificant, we found that the freeze-thaw process had a reduced effect. NGAL results were higher in Li-Hep tubes than in EDTA tubes. Thus, for blood samples we recommend use of EDTA tubes for NGAL measurements.

A low-gluten diet induces changes in the intestinal microbiome of healthy Danish adults.

Adherence to a low-gluten diet has become increasingly common in parts of the general population. However, the effects of reducing gluten-rich food items including wheat, barley and rye cereals in healthy adults are unclear. Here, we undertook a randomised, controlled, cross-over trial involving 60 middle-aged Danish adults without known disorders with two 8-week interventions comparing a low-gluten diet (2 g gluten per day) and a high-gluten diet (18 g gluten per day), separated by a washout period of at least six weeks with habitual diet (12 g gluten per day). We find that, in comparison with a high-gluten diet, a low-gluten diet induces moderate changes in the intestinal microbiome, reduces fasting and postprandial hydrogen exhalation, and leads to improvements in self-reported bloating. These observations suggest that most of the effects of a low-gluten diet in non-coeliac adults may be driven by qualitative changes in dietary fibres.

Plasma level of CXC-chemokine CXCL12 is increased in rheumatoid arthritis and is independent of disease activity and methotrexate treatment.

OBJECTIVE: Several actions of the chemokine CXCL12 have potential relevance for rheumatoid arthritis (RA). Interaction with CXCR4, the unique receptor for CXCL12, stimulates angiogenesis, mononuclear cell trafficking into the joints, lymphoid-tissue-like rearrangement of T cells within the synovium, and chondrocyte release of cartilage-degrading metalloproteinases. We investigated the level of CXCL12 in plasma (p-CXCL12) as a marker of RA diagnosis, RA disease activity, and response to methotrexate (MTX) treatment. METHODS: A prospective study including 36 patients with RA (ACR criteria) of at least 6 months' duration, and 50 sex and age matched healthy controls. ELISA for CXCL12 was performed on plasma prior to and after 16 and 28 weeks of MTX treatment in the patients with RA and once in controls. RESULTS: The p-CXCL12 was 1855 +/- 145 pg/ml in RA patients and 1273 +/- 79 pg/ml in controls (p < 0.001). During the 28 weeks of MTX treatment, the ACR disease activity variables decreased, whereas the p-CXCL12 level remained constant and increased. P-CXCL12 was not correlated to any ACR disease activity variable at any time (p > 0.05). CONCLUSION: Patients with RA had a significantly and constantly increased p-CXCL12 level compared to controls. The p-CXCL12 level was independent of any ACR disease activity variables, as well as response to MTX treatment.

Liquid chromatography tandem mass spectrometry assay for topiramate analysis in plasma and cerebrospinal fluid: validation and comparison with fluorescence-polarization immunoassay.

SUMMARY: The authors report the development and validation of a liquid chromatography tandem mass spectrometry assay (LC/MS/MS assay) for the analysis of topiramate (2,3:4,5-bis-o-(-1-methyl)-beta-D-fructopyranose sulfamate) in plasma and cerebrospinal fluid (CSF). Comparison is made with the commercially available fluorescence-polarization immunoassay (FPIA). LC/MS/MS ASSAY: Using the internal standard, 1,2:3,4-bis-o-(1-methylethylidene-alpha-D-galactopyranose sulfamate), a structural isomer, the calibration curve in plasma was linear in the concentration range of 0.02-20.0 mg/L (r(2) = 0.9998). The coefficients of variation in plasma were < or = 3%, and the accuracy ranged from 100% to 101% in the therapeutically relevant concentration range of 0.4-16.0 mg/L. In CSF, the mean recovery was 98%, and there was linearity between the nominal and the estimated concentration in the range of 1.5-20.0 mg/L (r(2)= 0.9996). FPIA: The calibration curve was linear in the concentration interval of 1.6-24.3 mg/L (r(2) = 0.9994), and the mean recovery was 96%. Accuracy in plasma was 99- 104%, and precision was 3.2-6.0%. In CSF, there was linearity between the nominal concentration and the estimated concentration in the range of 1.5-20.0 mg/L (r(2) = 0.9995), and the mean recovery was 100%. COMPARISON BETWEEN FPIA AND LC/MS/MS: There was a high correlation between the FPIA and the LC/MS/MS assay (r(2) = 0.9965 in plasma and r(2) = 0.9996 in CSF, P < 0.001 for both). In plasma and CSF, the two methods showed equal results, evaluated as the ratio between the two methods (plasma: median ratio = 1.00; 95% confidence interval [CI], 0.98-1.02, paired-sample test, P = 0.79; and CSF: median ratio = 1.00, 95% CI, 0.99-1.02, paired-sample test, P = 0.75). The coefficient of variation on the ratios between the two methods had similar levels: 5% in plasma and 3% in CSF. CONCLUSION: The new LC/MS/MS assay has favorable characteristics, being highly precise and accurate. FPIA also proved precise and accurate, and there was a high agreement with the LC/MS/MS assay in plasma and CSF. Either method displayed sufficient precision and accuracy and may thus be implemented in daily routine.

Folate, homocysteine, and cobalamin status in patients with rheumatoid arthritis treated with methotrexate, and the effect of low dose folic acid supplement.

OBJECTIVE: To investigate the effect of methotrexate (MTX) treatment of rheumatoid arthritis (RA) on folate metabolism, and to determine the effect of low dose folic acid on toxicity, efficacy, and folate status. METHODS: A 52-week prospective study of 81 patients with RA treated with MTX and self-administered low dose folic acid; 38 patients were included prior to MTX therapy, 33 patients continued established MTX therapy, and 10 patients were excluded. Drug efficacy and side effects were monitored with biochemical and clinical indicators. RESULTS: MTX treatment resulted in decreased concentrations of red blood cell (RBC) folate and a rise in plasma homocysteine. Intracellular concentrations of MTX were inversely correlated to RBC folate levels after treatment for a longer period (mean 41 months). Supplement with low dose folic acid prevented or diminished the influence of MTX on folate status and had a protective effect on MTX induced liver toxicity without changing the efficacy of MTX. CONCLUSION: MTX interferes with folate and homocysteine metabolism, and the intracellular concentration of MTX may play a role. Our results indicate low dose folic acid supplementation has a beneficial effect on MTX toxicity.

Blood tacrolimus levels and calcineurin phosphatase activity early after renal transplantation.

The toxicity of tacrolimus (FK) despite therapeutic levels (trough) has led us to investigate its relationship with the inhibition of calcineurin (CaN) in recently transplanted renal patients. Twenty-one patients taking FK had blood drawn on day 3 and 14 at 0,1,2,3,4 and 6h. CaN activity was measured by its ability to cleave 32P from a previously radiolabeled phosphorylated 19-amino acid peptide. Radioactivity was quantitated and results were converted to units CaN. FK concentration was measured simultaneously. Maximal suppression of CaN occurred after 2h on both days. Unlike FK levels, CaN activity returned to predose levels by 6h. Comparing mean CaN activity at time 0 with each subsequent time showed statistical significance at hours 1, 2 and 3 on each day. Comparing mean FK concentrations, similarly, revealed statistical significance at all hours. Area under CaN activity curve (AUCCaN) vs. mean FK levels failed to show significance. However, comparing AUCCaN with mean CaN activity was significant throughout. CaN capacity at time 0 and 6h (day 14) resulted in the best estimate of CaN inhibition. Prior to steady-state (day 3), the best estimate occurred at 2h. No single FK concentration seemed to be a reliable indicator of CaN inhibition.

Pharmacological investigation of the role of ion channels in salivary secretion.

The role of K+ and Cl- channels in salivary secretion was investigated, with emphasis on the potential role of Ca2+ -activated K+ channels. Ligand saturation kinetic assays and autoradiography showed large-conductance (BK) K+ channels to be highly expressed in rat submandibular and parotid glands, whereas low-conductance (SK) K+ channels could not be detected. To investigate the role of K+ and Cl- channels in secretion, intact rabbit submandibular glands were vascularly perfused and secretion induced by 10 microM ACh. Secretion was inhibited by 34+/-3% following perfusion with the general K+ channel inhibitor Ba2+ (5 mM), whereas organic inhibitors of BK (200 nM paxilline) or intermediate-conductance (IK) K+ channels (5 microM clotrimazole) had no effect. Secretion was strongly influenced by Cl- channel inhibitors, as 100 microM 5-nitro-2-(3-phenylpropylamino)benzoate (NPPB) completely abolished, while 10 microM NPPB, 20 microM NS1652 and 20 microM NS3623 reduced secretion by 34+/-3%, 23+/-3% and 59+/-4%, respectively. In conclusion, although high expression levels of BK channels were demonstrated, pharmacological tools failed to demonstrate any role for BK, IK or SK channels in salivary secretion in the rabbit submandibular gland. Other types of K+ channel, however, and particularly Cl- channels, are essential for ACh-induced salivary secretion.