In vivo monitoring of implant osseointegration in a rabbit model using acoustic sound analysis

Implant osseointegration can currently only be assessed reliably post mortem. A novel method that relies on the principle of acoustic sound analysis was developed to enable examination of the longitudinal progress of osseointegration. The method is based on a magnetic sphere inside a hollow cylinder of the implant. By excitation using an external magnetic field, collision of the sphere inside the implant produces a sound signal. Custom‐made titanium implants equipped thusly were inserted in each lateral femoral epicondyle of 20 New Zealand White Rabbits. Two groups were investigated: Uncoated, machined surface versus antiadhesive surface; and calcium phosphate‐coated surface versus antiadhesive surface. The sound analysis was performed postoperatively and weekly. After 4 weeks, the animals were euthanized, and the axial pull‐out strengths of the implants were determined. A significant increase in the central frequency was observed for the loose implants (mean pull‐out strength 21.1 ± 16.9 N), up to 6.4 kHz over 4 weeks. In comparison, the central frequency of the osseointegrated implants (105.2 ± 25.3 N) dropped to its initial value. The presented method shows potential for monitoring the osseointegration of different implant surfaces and could considerably reduce the number of animals needed for experiments. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:606–612, 2014.     

Dopamine Treatment of Brain-Dead Fisher Rats Improves Renal Histology But Not Early Renal Function in Lewis Recipients After Prolonged Static Cold Storage

BackgroundBrain death (BD) and cold preservation are major risk factors for an unfavorable transplantation outcome. Although donor dopamine treatment in brain-dead rats improves renal function and histology in allogeneic recipients, it remains to be assessed if this also holds true for the combinations of BD and prolonged static cold preservation.MethodsBD was induced in F344 donor rats, which were subsequently treated with NaCl 1 mL/h (BD, n = 11), NaCl/hydroxy ethyl starch (BD-norm, n = 10), or 10 μg/min/kg dopamine (BD-dopa, n = 10). Renal grafts were harvested 4 h after BD and transplanted into bilateral nephrectomized Lewis recipients 6 h after cold preservation in University of Wisconsin solution. Renal function was evaluated by use of serum creatinine and urea concentrations at days 0, 1, 3, 5, and 10. Ten days after transplantation, recipients were killed and the renal allografts were processed for light microscopy and immune histology.ResultsSerum urea concentrations at days 5 and 10 were significantly lower in recipients that received a renal graft from dopamine-treated rats; for serum creatinine, only a trend was observed at day 10. Immune histology revealed a lower degree of ED1-positive cells in the donor dopamine-treated group. Under light microscopy, Banff classification revealed significantly less intimal arteritis in these grafts (P < .05).ConclusionsAlthough donor dopamine treatment clearly improves renal histology in this model, the beneficial effect on early renal function was marginal. It remains to be assessed if donor dopamine treatment has a beneficial effect on renal function in long-term follow-up.     

Sequencing of LRP2 Reveals Multiple Rare Variants Associated with Urinary Trefoil Factor-3

Novel biomarkers are being investigated to identify patients with kidney disease. We measured a panel of 13 urinary biomarkers in participants from the Offspring Cohort of the Framingham Heart Study. Using an Affymetrix chip with imputation to 2.5 M single-nucleotide polymorphisms (SNPs), we conducted a GWAS of these biomarkers (n=2640) followed by exonic sequencing and genotyping. Functional studies in zebrafish were used to investigate histologic correlation with renal function. Across all 13 biomarkers, there were 97 significant SNPs at three loci. Lead SNPs at each locus were rs6555820 (P=6.7×10⁻⁴⁹; minor allele frequency [MAF]=0.49) in HAVCR1 (associated with kidney injury molecule-1), rs7565788 (P=2.15×10⁻¹⁶; MAF=0.22) in LRP2 (associated with trefoil factor 3 [TFF3]), and rs11048230 (P=4.77×10⁻⁸; MAF=0.10) in an intergenic region near RASSF8 (associated with vascular endothelial growth factor). Validation in the CKDGen Consortium (n=67,093) showed that only rs7565788 at LRP2, which encodes megalin, was associated with eGFR (P=0.003). Sequencing of exons 16–72 of LRP2 in 200 unrelated individuals at extremes of urinary TFF3 levels identified 197 variants (152 rare; MAF<0.05), 31 of which (27 rare) were nonsynonymous. In aggregate testing, rare variants were associated with urinary TFF3 levels (P=0.003), and the lead GWAS signal was not explained by these variants. Knockdown of LRP2 in zebrafish did not alter the renal phenotype in static or kidney injury models. In conclusion, this study revealed common variants associated with urinary levels of TFF3, kidney injury molecule-1, and vascular endothelial growth factor and identified a cluster of rare variants independently associated with TFF3.Serum creatinine, as used in most GFR estimating equations, is the primary biomarker of CKD.¹ Creatinine has significant limitations as a biomarker. It is insensitive to early declines in kidney function, and there are important extrarenal factors that influence its concentration, thus increasing the potential for misclassification when it is used to diagnose renal disease.² As a result, novel biomarkers are being investigated that could allow earlier and more accurate diagnosis of CKD.³ It is likely, however, that these biomarkers also have non-GFR determinants, including genetic factors. For example, levels of cystatin C, a novel GFR biomarker, are known to be influenced by both nongenetic factors, such as adiposity and the metabolic syndrome,⁴ and the presence of specific genetic variants in the cystatin C-gene cluster.⁵Genome-wide association studies (GWAS) allow for the evaluation of genetic associations of biomarkers in an unbiased manner. These studies could illuminate previously unrecognized pathways for CKD pathogenesis, thus identifying new potential molecular targets for therapeutic intervention. Multiple variants have been identified in association with kidney function through GWAS,⁶ whereas a variant in CUBN encoding cubilin, a proximal tubular transport protein, has been associated with albuminuria.⁷ Recently, a GWAS identified a locus at PTGDS in association with another kidney biomarker, β-trace protein.⁸To gain additional insight into biologic pathways of renal function and kidney injury, we measured a panel of 13 urinary biomarkers in participants from the Framingham Heart Study (FHS) and performed a GWAS of their levels. Here, we report the primary results from these studies as well as follow-up work to identify whether rare variants in LRP2 are associated with levels of trefoil factor 3 (TFF3).     

Betablocker in der Therapie der chronischen Herzinsuffizienz

Hintergrund: Die antiadrenerge Therapie mit Betablockern bei der chronischen Herzinsuffizienz hat sich nach 25 Jahren von einer Kontraindikation zu einer etablierten Behandlungsform additiv zu einer konventionellen Basistherapie mit Diuretikum, einem ACE-Hemmer (alternativ AT1-Antagonist) und optional Digitalis entwickelt. Pathophysiologie: Eine kompensatorische Überaktivierung des sympathischen Nervensystems bei chronischer Herzinsuffizienz resultiert in der Induktion verschiedener, für die Herzmuskelzelle letztlich deletärer biologischer Signale. Die Tatsache, dass diese Signale über adrenerge Rezeptoren vermittelt werden, stellt die pathophysiologische Grundlage für den Einsatz einer Betablockade bei Herzinsuffizienz dar. Therapeutische Empfehlungen nach Studienlage Die drei größten Betablockerinterventionsstudien (CIBIS II, MERIT-HF, COPERNIKUS) zeigten unter additiver Gabe von Bisoprolol, Metoprolol bzw. Carvedilol einen eindeutigen Überlebensvorteil für die mit diesen Betablockern behandelten Patienten. Nach heutiger Datenlage sollten alle Patienten mit stabiler chronischer Herzinsuffizienz (NYHA II-IV) und nachgewiesener linksventrikulärer Funktionsstörung (LVEF < 45%) einen der drei genannten Betablocker erhalten. Eine Betablockertherapie sollte grundsätzlich nur bei stabilen Patienten additiv zu einem ACE-Hemmer und einem Diuretikum mit einer sehr niedrigen Dosis begonnen und langsam über mehrere Wochen bis zur maximal vom Patienten tolerierten Dosis auftitriert werden ("start low, go slow but high"). Der Erfolg der "paradoxen Intervention" stellt sich erst nach etwa 2-3 Monaten ein. Background: Once contraindicated, beta-blockers have become an established, evidence-based, recommended treatment concept in chronic heart failure during the last years. Pathophysiology: The increased activation of the adrenergic system in heart failure syndrome, which leads to transmission of several adverse biological signals to myocytes through adrenergic receptors, provides the rationale for the use of beta-blockers in patients with chronic heart failure. Long-term treatment with different types of beta-blockers additive to an ACE-inhibitor and diuretics results in normalization of left ventricular shape, an improvement of left ventricular function, and a reduction of hospitalization rate for heart failure. Hemodynamic and clinical improvement is independent of etiology and severity of left ventricular dysfunction. Therapeutical Recommendations Accordings to Studies: Adequately powered clinical trials (CIBIS II, MERIT-HF, COPERNIcUS) testing different types of beta-blockers (bisoprolol, metoprolol, carvedilol) clearly demonstrated that total mortality and the incidence of sudden cardiac death were significantly reduced in heart failure patients by each of these agents. On the basis of all available evidence, all patients with chronic, stable heart failure (NYHA class II-IV) and with impaired left ventricular function (LVEF < 45%) should receive one of the three above mentioned beta-blockers. Protective effects of beta-blockers in heart failure comprise decrease in heart rate, a decrease of energy consumption, antifibrillatory effects, protection against adrenergic overactivation, and hence, inhibition of myocardial cell necrosis. Moreover, several beta-blockers induce an up-regulation of beta-receptors leading to an improvement of contractility during long-term treatment. It should be mentioned that even a low dosage of beta-blockers exert negative inotropic effects and may lead to a deterioration of hemodynamics and heart failure symptoms in patients with heart failure. The patients treated should be informed that the success of the "paradoxical intervention" will be obvious until 2-3 months after initiation of additional beta-blocker therapy. Beta-blocker treatment for heart failure should be started in stable patients with a very low initial dosage and then up-titrated to the maximal tolerated dosage and should be continued indefinitely. Mortality reduction by beta-blockade in heart failure is no class effect. So far, beneficial effects could only be demonstrated for lipophilic agents. Whether the non-selective beta-blocker carvedilol with additional properties has advantages over the beta-1-selective metoprolol is currently investigated in the COMET (Carvedilol or Metoprolol European Trial) study. Despite the impressive effects in terms of morbidity and mortality reduction, the transfer of these benefits to the clinical practice setting is difficult, with international data showing only 10% of patients with heart failure being treated.     

Identification of surface residues mediating tissue factor binding and catalytic function of the serine protease factor VIIa

Factor VIIa (VIIa), the serine protease that initiates the coagulation pathways, is catalytically activated upon binding to its cell surface receptor and cofactor tissue factor (TF). This study provides a comprehensive analysis of the functional surface of VIIa by alanine scanning mutagenesis of 112 residues. Residue side chains were defined which contribute to TF binding and factor X hydrolysis. Energetically important binding contacts at the interface with TF were identified in the first epidermal growth factor domain of VIIa (Gln-64, Ile-69, Phe-71, Arg-79) and in the protease domain (Arg-277, Met-306, Asp-309). The observed energetic defects are in good agreement with the corresponding residues in TF, suggesting that the VIIa light chain plays a prominent role in high affinity binding of cofactor. Mutation of protease domain interface residues indicated that TF allosterically influences the active site of VIIa. Stabilization of a labile zymogen to enzyme transition could explain the activating effect of TF on VIIa catalytic function. Residues important for factor X hydrolysis were found in three regions of the protease domain: (i) specificity determinants in the catalytic cleft and adjacent loops, (ii) an exosite near the TF binding site, and (iii) a large electronegative exosite which is in a position analogous to the basic exosite I of thrombin. TF regions involved in factor X activation are positioned on the same face of the TF·VIIa complex as the two exosites identified on the protease domain surface, providing evidence for an extended interaction of TF·VIIa with macromolecular substrate.     

Natural history of small and medium-sized side branches after coronary stent implantation

Objective Our purpose was to identify angiographic and procedural predictors for acute and late side branch occlusion after coronary stent implantation. Methods We evaluated 185 patients with 185 lesions with 255 side branches with a mean reference diameter of 1.45 ± 0.38 mm; the lesions were covered by 240 stents. Angiographic follow-up was completed in 99 patients with 133 side branches 206 ± 120 days after stent implantation and clinical follow-up was available in 136 patients. Side branch occlusion (SBO) was defined as a Thrombolysis In Myocardial Infarction (TIMI) flow ≤1. Results Acute SBO affected 54 side branches in 49 patients and was not associated with death or Q-wave infarction. By logistic regression, independent predictors for acute SBO were (1) the reference side branch diameter (RLD) at baseline (OR [odds ratio] 0.217, 95% CI 0.07-0.67, P = .008); (2) an ostial side branch stenosis before stenting (OR 2.96, 95% CI 1.26-6.95, P = .013); (3) the involvement of the side branch origin within the lesion of the parent vessel (OR 2.77, 95% CI 1.17-6.57, P = .021); and (4) the balloon-to-artery ratio (OR 4.66, 95% CI 1.18-18.42, P = .028). Among the initially occluded side branches, 81.8% were spontaneously reperfused at follow-up. Late SBO involved 12% of the side branches without impaired antegrade flow after stenting and was predicted by the initial RLD of the side branch (OR 0.07, 95% CI 0.01-0.8, P = .032). Chronic SBO occurred in 13.5% of cases and was also predicted by the baseline RLD (OR 0.13, 95% CI 0.02-0.8, P = .028). Conclusions Acute SBO after stenting occurred in 21.2% of cases and had a benign course. Most acutely occluded side branches underwent late spontaneous reperfusion. A baseline side branch diameter >1.4 mm predicted a preserved antegrade flow immediately after stent implantation, as well as during follow-up. (Am Heart J 2002;143:627-35.)     

Consensus Paper: Language and the Cerebellum: an Ongoing Enigma

In less than three decades, the concept “cerebellar neurocognition” has evolved from a mere afterthought to an entirely new and multifaceted area of neuroscientific research. A close interplay between three main strands of contemporary neuroscience induced a substantial modification of the traditional view of the cerebellum as a mere coordinator of autonomic and somatic motor functions. Indeed, the wealth of current evidence derived from detailed neuroanatomical investigations, functional neuroimaging studies with healthy subjects and patients and in-depth neuropsychological assessment of patients with cerebellar disorders shows that the cerebellum has a cardinal role to play in affective regulation, cognitive processing, and linguistic function. Although considerable progress has been made in models of cerebellar function, controversy remains regarding the exact role of the “linguistic cerebellum” in a broad variety of nonmotor language processes. This consensus paper brings together a range of different viewpoints and opinions regarding the contribution of the cerebellum to language function. Recent developments and insights in the nonmotor modulatory role of the cerebellum in language and some related disorders will be discussed. The role of the cerebellum in speech and language perception, in motor speech planning including apraxia of speech, in verbal working memory, in phonological and semantic verbal fluency, in syntax processing, in the dynamics of language production, in reading and in writing will be addressed. In addition, the functional topography of the linguistic cerebellum and the contribution of the deep nuclei to linguistic function will be briefly discussed. As such, a framework for debate and discussion will be offered in this consensus paper.     

Bendamustine and prednisone in combination with bortezomib (BPV) in the treatment of patients with newly diagnosed/untreated multiple myeloma

Introduction

Bortezomib is a proteasome inhibitor that has shown important clinical efficacy either as a single agent or in combination in patients with multiple myeloma (MM). In the present protocol, bortezomib was combined with bendamustine and prednisone, in order to assess the efficacy and safety of this combination therapy in patients with newly diagnosed/untreated MM.

Methods

Between June 2006 and October 2013, 49 patients with newly diagnosed/untreated MM were treated with bendamustine 60 mg/m² on days 1 and 2, bortezomib 1.3 mg/m² on days 1, 4, 8 and 11, and prednisone 100 mg on days 1, 2, 4, 8 and 11 bendamustine, prednisone and bortezomib (BPV) once every 21 days. Patients were divided into three groups: group A (n = 19) consisted of patients with normal renal function or mild dysfunction (eGFR ≥60 ml/min), group B (n = 15) patients with moderate or severe renal dysfunction (eGFR 15–59 ml/min) and group C (n = 15) patients with renal failure/dialysis (eGFR <15 ml/min).

Results

A median number of two (range 1–5) BPV treatment cycles were given to the patients. The majority of the patients (n = 40, 82 %) responded after at least one cycle of BPV therapy with five stringent complete responses (CRs), nine near complete responses, 12 very good partial responses and 14 partial responses. Five patients had MR, three stable and one progressive disease. After a median observation time of 13 months, progression-free survival (PFS) and overall survival (OS) at 12 months were 92 and 94 %, respectively, for patients with normal renal function or mild renal dysfunction (group A) and 83 and 93 %, respectively, for patients with moderate or severe renal dysfunction (group B). Outcome for these patients was slightly better but not statistically significantly better than that for patients with renal failure/dialysis (group C), who had a PFS, and OS of 66 % (p = 0.08) and 73 % (p = 0.05), respectively.

Summary

These results indicate that this BPV combination is feasible, effective and well tolerated in patients with newly diagnosed MM and normal or impaired renal function.