The development of clinical activity in relapsing-remitting MS is associated with a decrease of FasL mRNA and an increase of Fas mRNA in peripheral blood

In this longitudinal study, we examined the expression of Fas, FasL, CCR3, CCR5 and CXCR3 mRNA in peripheral blood mononuclear cells (PBMCs) of secondary progressive (SP) and relapsing-remitting (RR) multiple sclerosis (MS) patients. In RR patients, FasL, CCR3 and CCR5 mRNA levels were increased prior to the exacerbations, but these decreased during clinical activity, while mRNA levels of Fas increased. SP patients have increased the levels of Fas and FasL mRNA; the latter was particularly increased during lesional activity.Our data support the hypothesis that changes in Fas and FasL mRNA related to clinical activity are due to the migration of inflammatory cells to the central nervous system (CNS).     

Bismuth overdosing-induced reversible nephropathy in rats

Overdosing of colloidal bismuth subcitrate (CBS), used to treat peptic ulcers and Helicobacter pylori infections, has been reported to result in serious, though reversible, nephrotoxicity in humans. However, little is known about the nature of the renal damage induced by bismuth (Bi), and no well-described experimental model exists. Single large oral CBS doses (0.75, 1.5, and 3.0 mmol Bi/kg) were administered to three groups of 20 female Wistar rats. A control group (n = 20) received only the vehicle. Standard kidney function parameters, urinary excretion of N-acetyl-beta-D-glucosaminidase (NAG) and the Bi content were monitored in blood, urine, liver, and kidneys for 14 days. A dose of 3.0 mmol Bi/kg, 100 times the daily therapeutic dose, caused kidney damage within 6 h as detected by proteinuria, glucosuria, and elevated plasma urea and plasma creatinine levels. The kidneys of all animals, except two that died, recovered functionally within 10 days. At a dose of 1.5 mmol Bi/kg, clinical parameters changed less and normalized within 48 h, whereas a dose of 0.75 mmol Bi/kg induced no changes. Histological evaluation revealed that the S3 tubular segment necrotized first with additional necrotization of the S1/S2 segment when more Bi was absorbed. The lesions were accompanied by interstitial infiltrates of CD45+ leukocytes. In summary, we developed a rat model for Bi-induced reversible nephropathy. A large single oral overdose of CBS administered to Wistar rats led to damage to the proximal tubule, especially in the last segment.     

Suppression of atrial fibrillation by multisite and septal pacing in a novel experimental model

OBJECTIVES: To evaluate the preventive efficacy of multisite and septal atrial pacing in an experimental model. METHODS: Sterile right atrial pericarditis was induced in 12 foxhounds to provide an anatomical substrate for atrial fibrillation (AF). As a trigger mechanism, atrial extrasystoles were simulated by constant asynchronous pacing at a cycle length of 1000 ms from randomly selected right or left atrial electrodes, using a biatrial epicardial multielectrode with 128 bipoles. Additionally, a transvenous pacing lead was screwed into the interatrial septum. Four electrodes located in the high and low right (HRA/LRA) and left atrium (HLA/LLA) were selected for preventive multisite stimulation. Constant pacing at a cycle length 30 ms below sinus rate was applied from the following site(s): HRA, septal, HRA+LRA, HRA+LLA, HRA+LRA+LLA and HRA+LRA+HLA+LLA (order randomized). Number and duration of AF episodes were studied during 10 min intervals, separated by 5 min pauses, respectively. To validate the model, the protocol was repeated 10 min after i.v. bolus administration of D,L-sotalol (1 mg/kg body weight). RESULTS: The number of AF episodes decreased with increasing number of pacing sites, reaching statistical significance compared to HRA stimulation for quadruple-site and single-site septal pacing only (P<0.05). Single-site septal was as efficient as quadruple-site pacing in suppressing AF. The duration of AF episodes was not significantly affected by the pacing configuration. D,L-sotalol almost completely suppressed AF irrespective of the pacing configuration used. CONCLUSIONS: In this novel experimental model, quadruple-site and septal pacing effectively suppress paroxysmal AF.     

Mitogenic signalling in the absence of epidermal growth factor receptor activation in a human glioblastoma cell line

Epidermal growth factor receptor (EGFR) gene amplification and overexpression are commonly present in glioblastoma, and confer advantages of growth, invasiveness and radio/chemotherapy-resistance for tumour cells. Here, we assessed the role of EGFR activation for downstream mitogenic signalling in the commonly used glioblastoma cell line U251. Despite the high expression level, activation of EGFR under standard culture conditions was low. Intact EGFR function was verified by the rapid phosphorylation of EGFR and downstream mitogen-activated protein (MAP) kinase ERK1/2 upon addition of exogenous EGF to serum-starved cells. By contrast, addition of fetal bovine serum (FBS) activated downstream ERK1/2 via the MAP kinase kinase without phosphorylating EGFR. A phospho-receptor tyrosine kinase array showed FBS-induced activation of insulin-like growth factor-1 receptor (IGF-1R), and the IGF-1R inhibitor AG1024 inhibited FBS-induced phosphorylation of ERK1/2, implying IGF-1R as the major driver of FBS-associated mitogenic signalling in the absence of exogenous EGF. These findings have important implications for in vitro drug testing in glioblastoma. Moreover, activation of ERK1/2 was also strongly influenced by growth state and cell density of U251 cultures. Re-seeding exponentially growing cultures at high cell density induced p27/CDKN1B expression and suppressed P-ERK1/2 indicating a certain regulation of proliferation by contact inhibition. Strikingly, highly activated ERK1/2 signalling and cell-cycle progression occurred when cells were released from plateau phase regardless of high seeding density. This phenomenon might implicate a proliferation response in the early recurrence observed after clinical therapy in glioblastoma patients. However, whether it will recapitulate in vivo remains to be demonstrated.     

Role of neural guidance signals in blood vessel navigation

Despite the tremendous progress achieved in both vasculogenesis and angiogenesis in the last decade, little is still known about the molecular mechanisms underlying the pathfinding of blood vessels during their formation. However, emerging evidence shows that different axonal guidance cues, including members of the Slit and semaphorin families, are also involved in the blood vessel guidance, suggesting that blood vessels and nerves share common mechanisms in choosing and following specific paths to reach their respective targets. These promising findings open novel avenues not only in vascular biology but also in therapeutic angiogenesis. Indeed, the identification of new molecules involved in the guidance of blood vessels may be helpful in designing angiogenic strategies, which would insure both the formation of new blood vessels and their guidance into an organized and coordinated network.     

Effect of cardiac resynchronization therapy on conversion of persistent atrial fibrillation to sinus rhythm

Background  Spontaneous conversion of persistent atrial fibrillation to sinus rhythm (SR) has anecdotally been reported following cardiac resynchronisation therapy. Objective  This monocenter observational study was designed to estimate the incidence of spontaneous conversion of persistent atrial fibrillation to SR in consecutive patients implanted with a cardiac resynchronisation device. Methods and results  A total of 46 patients with persistent atrial fibrillation (≥4 weeks pre-implant), left bundle branch block (QRS > 130 ms), left ventricular ejection fraction <0.35 and NYHA III or IV heart failure were implanted with a cardiac resynchronisation pacemaker or defibrillator and followed for at least 6 months between 6/2000 to 12/2006. During 22 ± 9 (7–34) months of follow-up, eight out of 46 patients (17%) converted to SR. Spontaneous conversion was encountered in seven cases, whereas one patient converted due to an ICD shock delivered for ventricular tachycardia; in the latter patient, previous ICD shocks had not converted atrial fibrillation. The time interval from device implantation to conversion was 12 ± 11 (3–31) months. In patients converting to SR, the duration of atrial fibrillation before device implantation was significantly shorter than in patients remaining in atrial fibrillation (15 ± 13 vs. 53 ± 58 months, P = 0.001). Echocardiographic parameters such as left ventricular ejection fraction, left ventricular enddiastolic diameter, left atrial diameter did not differ significantly between converting and non-converting patients. However, patients converting to SR showed a significant reduction in systolic pulmonary artery pressure on CRT vs. before CRT (45 ± 13 vs. 29 ± 5 mmHg, P = 0.008). Conclusions  This pilot study suggests that CRT favors spontaneous conversion of persistent AF to SR in a minority of patients. If confirmed by larger clinical studies, atrial lead implantation would be encouraged in these patients, in order to provide AV synchronous pacing in case of spontaneous conversion or successful cardioversion to SR on cardiac resynchronisation therapy. M. Hauck and A. Bauer contributed equally to this work.     

Parallel-transmit-accelerated spatially-selective excitation mri for reduced-fov diffusion-weighted-imaging of the pancreas

Objectives

To find out whether the use of accelerated 2D-selective parallel-transmit excitation MRI for diffusion-weighted EPI (pTX-EPI) offers advantages over conventional single-shot EPI (c-EPI) with respect to different aspects of image quality in the MRI of the pancreas.

Materials and methods

The MRI examinations of 33 consecutive patients were evaluated in this prospective and IRB-approved study. PTX-EPI was performed with a reduced (zoomed) FOV of 230 × 118 mm². The 2D-RF pulse of pTX-EPI was accelerated, i.e. shortened by a factor of 1.7 (pTX-acceleration factor). C-EPI used a full-FOV of 380 × 285 mm². In a qualitative analysis, two experienced readers evaluated 3 different aspects of image quality on 3- to 5-point Likert scales. Additionally, apparent diffusion coefficients (ADCs) were determined in both c-EPI and pTX-EPI in normal-appearing pancreatic tissue using regions of interests (ROIs). Mean ADC values and standard deviations were compared between the two techniques.

Results

The reduced-FOV pTX-EPI was superior to c-EPI with respect to overall image quality (p < 0.0001) and identifiability of the pancreatic ducts (p < 0.01). Artifacts were significantly less severe in pTX-EPI (p < 0.01). The mean ADC values of c-EPI (1.29 ± 0.19 × 10⁻³ mm²/s) and pTX-EPI (1.27 ± 0.17 × 10⁻³ mm²/s) did not differ significantly between the two techniques (p = 0.44). The variation within the ROIs as measured by the standard deviation was significantly lower in pTX-EPI (0.095 × 10⁻³ mm²/s) than in c-EPI (0.135 × 10⁻³ mm²/s), p < 0.05.

Conclusions

PTX-accelerated EPI with spatially-selective excitation and reduced FOV leads to substantial improvements in DWI of the pancreas with respect to different aspects of image quality without significantly influencing the ADC values.     

Liver regeneration in acute severe liver impairment: a clinicopathological correlation study.

BACKGROUND: Although normally quiescent, the adult mammalian liver possesses a great capacity to regenerate after different types of injury. Major players in the regeneration process are mature residual cells, including hepatocytes, cholangiocytes and stromal cells. However, if the regenerative capacity of mature cells is impaired, hepatic progenitor cells (HPCs) are activated and expand into the liver parenchyma. Upon transit amplification, the progenitor cells generate new hepatocytes and biliary cells to restore liver homeostasis. AIMS/METHODS: To study the relationship between different histopathological parameters as well as their correlations with clinical parameters and outcome, we examined liver specimens from 74 patients with acute or subacute severe liver impairment by immunohistochemistry for CK7/CK19 (evaluation of HPCs activation/differentiation), Mib1(Ki 67)/P21 (evaluation of proliferative activity/proliferation arrest of hepatocytes) and hematoxylin and eosin (evaluation of hepatocyte loss). RESULTS: Of the 74 patients, 32% survived without transplantation, 14% died without transplantation and 54% were transplanted. Our results show that a threshold of 50% loss of hepatocytes, associated with significant decrease in the proliferative activity of remaining mature hepatocytes, is needed for extensive hepatic progenitor cell activation. Such activation is a sign of disease severity and occurs early (within 1 week) in the disease course. However, development of intermediate hepatocytes, suggesting HPCs differentiation towards mature hepatocytes, takes at least 1 week's time. We found a positive correlation between histopathological parameters (percentage hepatocyte loss, number of proliferating hepatocytes and number of HPCs) and clinical parameters of liver impairment such as model for end stage liver diseases (MELD). Surviving patients compared with those who either died or were transplanted had significantly less hepatocyte loss, less HPCs activation and more mature hepatocyte proliferative activity. Hepatocyte proliferative activity and degree of hepatocyte loss were the most important independent histopathological parameters in predicting outcome. CONCLUSION: Liver biopsy can provide important additional information in a patient with severe acute liver impairment.     

Impact of Baseline Renal Function on the Efficacy and Safety of Aliskiren Added to Losartan in Patients With Type 2 Diabetes and Nephropathy

OBJECTIVE

Proteinuric diabetic patients with reduced glomerular filtration rate (GFR) are at high risk of renal and cardiovascular disease progression and treatment-related adverse events. This post hoc analysis assessed the efficacy and safety of aliskiren added to the maximal recommended dose of losartan according to baseline estimated GFR (eGFR) (stage 1–3 chronic kidney disease [CKD]).

RESEARCH DESIGN AND METHODS

In the Aliskiren in the Evaluation of Proteinuria in Diabetes (AVOID) study, 599 hypertensive patients with type 2 diabetes and nephropathy received 6 months of aliskiren (150 mg daily titrated to 300 mg daily after 3 months) or placebo added to 100 mg losartan and optimal antihypertensive therapy. Exclusion criteria included eGFR <30 ml/min per 1.73 m² and serum potassium >5.1 mmol/l.

RESULTS

Baseline characteristics were similar between treatment groups in all CKD stages. The antiproteinuric effects of aliskiren were consistent across CKD stages (19, 22, and 18% reduction). In the stage 3 CKD group, baseline serum creatinine levels were equal, but renal dysfunction, prespecified as a postrandomization serum creatinine elevation >176.8 μmol/l (2.0 mg/dl) occurred more frequently in the placebo group (29.2 vs. 13.6%, P = 0.032). Serum potassium elevations >5.5 mmol/l (based on a single measurement) were more frequent with aliskiren (22.5 vs. 13.6%) in stage 3 CKD. Adverse event rates were similar between treatments, irrespective of CKD stage.

CONCLUSIONS

Aliskiren added to losartan reduced albuminuria and renal dysfunction and was well tolerated, except for hyperkalemia (stage 3), independent of baseline CKD stage in patients with type 2 diabetes, hypertension, and nephropathy.Renin inhibition is a new treatment modality that blocks the renin-angiotensin-aldosterone system (RAAS) at the first rate-limiting step of the cascade. Because the direct renin inhibitor aliskiren recently was approved for the treatment of hypertension, it seemed a reasonable assumption that this drug would also possess antiproteinuric qualities. In theory, renin inhibition will decrease plasma renin activity and levels of circulating angiotensin I and angiotensin II, leading to more efficient RAAS blockade. A previous study from our group has suggested a higher degree of RAAS blockade by the use of the combination of aliskiren and the angiotensin II receptor blocker irbesartan (1). Whereas this hypothesis was formerly proven only in small studies (1,2), the Aliskiren in the Evaluation of Proteinuria in Diabetes (AVOID) study (3) was the first double-blind, randomized controlled trial to demonstrate the antiproteinuric ability of aliskiren (300 mg once daily) as an add-on to standard treatment, including the recommended dose of an angiotensin II receptor blocker (losartan), in patients with type 2 diabetes, hypertension, and nephropathy.There is an evident unmet need for improved renoprotective therapies because this patient group constitutes the majority of patients requiring dialysis in the western world (4). Reduction in proteinuria from RAAS blockade has been shown to be associated with improved renal and cardiovascular prognosis (5,6), and although its use remains controversial, albuminuria is the best available surrogate marker for renal protection. Combination treatment with renin inhibition and angiotensin II receptor blockade is evolving as a new antiproteinuric treatment, but not much is known about the impact of underlying renal function on the safety and efficacy of this treatment. The aim of this post hoc analysis was to investigate the efficacy and safety of add-on treatment with aliskiren in the AVOID study across different stages of estimated glomerular filtration rate (eGFR) at baseline.     

IN VITRO INTERACTION OF MOUSE HEPATITIS VIRUS AND MACROPHAGES FROM GENETICALLY RESISTANT MICE : I. ADSORPTION OF VIRUS AND GROWTH CURVES

Peritoneal macrophages from genetically resistant C₃H mice and genetically susceptible Princeton (PRI) mice adsorbed the MHV (PRI) strain of mouse hepatitis virus equally well. The difference between the permissive cells and the nonpermissive ones seems to reside in the ability of the former to "eclipse" the virus and, subsequently, support virus replication. C₃H cells exposed to low multiplicities of the virus remained intact with no demonstrable viral replication. Virus, taken up by the resistant cells, was protected from heat and underwent slow inactivation while few or no virus particles were released into the medium.