Local cooling reduces regional bone blood flow

Local cooling is very common after bone and joint surgery. Therefore the knowledge of bone blood flow during local cooling is of substantial interest. Previous studies revealed that hypothermia leads to vasoconstriction followed by decreased blood flow levels. The aim of this study was to characterize if local cooling is capable of inducing reduced blood flow in bone tissue using a stepwise‐reduced temperature protocol in experimental rabbits. To examine bone blood flow we utilized the fluorescent microsphere (FM) method. In New Zealand white rabbits one randomly chosen hind limb was cooled stepwise from 32 to 2°C, whereas the contra lateral hind limb served as control. Injection of microspheres was performed after stabilization of bone and muscle temperature at each temperature level. Bones were removed, dissected and fluorescence intensity was determined to calculate blood flow values. We found that blood flow of all cooled regions decreased relative to the applied external temperature. At maximum cooling blood flow was almost completely disrupted, indicating local cooling as powerful regulatory mechanism for regional bone blood flow (RBBF). Postoperative cooling therefore may lead to strongly decreased bone blood flow values. As a result external cooling has capacity to both diminish bone healing and reduce bleeding complications. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31:1820–1827, 2013     

Histone deacetylase inhibitors as potential therapeutic approaches for chordoma: An immunohistochemical and functional analysis

Chordomas are rare malignancies of the axial skeleton. Therapy is mainly restricted to surgery. This study investigates histone deacetylase (HDAC) inhibitors as potential therapeutics for chordomas. Immunohistochemistry (IHC) was performed using the HDAC 1–6 antibodies on 50 chordoma samples (34 primary tumors, 16 recurrences) from 44 patients (27 male, 17 female). Pan‐HDAC‐inhibitors Vorinostat (SAHA), Panobinostat (LBH‐589), and Belinostat (PXD101) were tested for their efficacy in the chordoma cell line MUG‐Chor1 via Western blot, cell cycle analysis, caspase 3/7 activity (MUG‐Chor1, UCh‐1), cleaved caspase‐3, and PARP cleavage. p‐Values below 0.05 were considered significant. IHC was negative for HDAC1, positive for HDAC2 in most (n = 36; 72%), and for HDACs 3–6 in all specimens available (n = 43; 86%). HDAC6 expression was strongest. SAHA and LBH‐589, but not PXD101 caused a significant increase of G2/M phase cells and of cleaved caspase‐3 (p = 0.0003, and p = 0.0014 after 72 h, respectively), and a peak of caspase 3/7 activity. PARP cleavage confirmed apoptosis. The presented chordoma series expressed HDACs 2–6 with strongest expression of HDAC6. SAHA and LBH‐589 significantly increased apoptosis and changed cell cycle distribution in vitro. HDAC‐inhibitors should be further evaluated as therapeutic options for chordoma. © 2013 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 31:1999–2005, 2013     

PDE5 inhibition against acute renal ischemia reperfusion injury in rats: does vardenafil offer protection?

Purpose

To evaluate the effect of vardenafil on renal function after renal ischemia–reperfusion (IR) injury (IRI) in a rat model.

Materials and methods

Seventy-one Wistar rats were divided into 7 groups including (1) a vehicle-treated group, (2) a vehicle pretreated-IR group, (3–6) vardenafil pretreated-IR groups in doses of 0.02, 0.2, 2 and 20 μg/kg, respectively, (7) a group of IR followed by treatment with 2 μg/kg of vardenafil. Vardenafil or vehicle solution was administered one hour before unilateral nephrectomy and the induction of 45 min of ischemia on the contralateral kidney by clamping of renal pedicle. Four hours of reperfusion were allowed after renal ischemia. Studied parameters were serum creatinine, fractional excretion of sodium (FENa), and histological evaluation of renal specimens. In addition, renal tissue cGMP levels, ERK1/2 phosphorylation as well as renal function by renal scintigraphy were also evaluated.

Results

Administration of vardenafil before the induction of ischemia resulted in a significant reduction in creatinine and FENa levels as well as in less histological lesions observed in treated kidneys in comparison with the vehicle-treated group. The underlying mechanism of cytoprotection was cGMP depended and involved the phosphorylation of ERK proteins. Renal scintigraphy confirmed that PDE5 inhibition attenuates renal IRI.

Conclusions

Vardenafil attenuates renal IRI. Based on similar results from relevant studies on other PDE-5 inhibitors in renal and cardiac IRI, it can be assumed that all PDE-5 inhibitors share a common mechanism of cytoprotection.     

Effect of platelet‐rich plasma on the biologic activity of the human rotator‐cuff fibroblasts: A controlled in vitro study

To assess the in vitro effect of platelet‐rich plasma (PRP) on biological activity of the human rotator cuff fibroblasts and to describe the optimal dose‐response to maximize cellular stimulation while reducing potential risk. Rotator cuff (RC) fibroblasts of n = 6 patients (mean age of 65.2 years) undergoing arthroscopic cuff tear reconstruction were cultured in vitro for 21 days and stimulated with PRP in three different concentrations (1‐, 5‐, and 10‐fold). Samples were obtained for DNA and GAG measurement at 1, 7, 14, and 21 days. The biological outcomes were regressed on the PRP concentration. The application of PRP significantly influenced the fibroblast proliferation and activity of the human rotator cuff with elevated glycosaminoglycan (GAG) and DNA levels. The dosage of PRP had the significantly highest impact on this proliferation using a onefold or fivefold application. PRP has a significant effect on fibroblast proliferation of the human rotator cuff in vitro with an optimal benefit using a onefold or fivefold PRP concentration. This study justifies further in vivo investigations using PRP at the human rotator cuff. © 2013 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 31:1249–1253, 2013     

Effect of TNF‐alpha blockade on coagulopathy,survival and endothelial activation in xenoperfused porcine kidneys

Background: Following pig to primate kidney transplantation, endothelial cell activation and xenogenic activation of the coagulation (XAC) system of the recipient eventually leading to organ dysfunction and disseminated intravascular coagulation (DIC) can be observed (1). In this study we examined the effect of a TNF‐Receptor‐Fusionprotein (TNF‐RFP) on XAC and endothelial cell activation utilizing an appropriate ex‐vivo perfusion system. Methods: Using an ex‐vivo perfusion circuit based on C1‐Inhibitor (C1‐Inh) and low dose heparin administration, we have analysed XAC following contact of human blood with porcine endothelium. Porcine kidneys were recovered following in situ cold perfusion with HTK organ preservation solution and were immediately connected to a perfusion circuit utilizing freshly drawn pooled porcine or human AB blood. The experiments were performed in three individual groups: autologous perfusion (n = 5), xenogenic perfusion without any further pharmacological intervention (n = 10) or with addition of TNF‐RFP (n = 5). After perfusion tissue samples were obtained for QPCR and immunohistological analyses. Endothelial cell activation was assessed by measuring the expression levels of E‐Selectin, ICAM‐1 and VCAM‐1 in QPCR. Results: Kidney survival during organ perfusion with human blood, CI‐Inh, heparin but without any further pharmacological intervention was 126 ± 78 min. XAC was observed with significantly elevated concentrations of d‐Dimer, thrombin antithrombin complex (TAT), resulting in formation of multiple microthrombi. Endothelial cell activation was pronounced, as shown by increased expression of E‐Selectin and VCAM‐1. In contrast, pharmacological intervention with TNF‐RFP reduced the consumption of antithrombin and fibrinogen and prolonged organ survival to 240 min (±0). Additionally, formation of microtrombi was reduced compared to the xenogenic control without pharmacological intervention. Remarkably, also endothelial cell activation was significantly reduced in the TNF‐RFP group. Conclusions: We conclude that TNF‐RFP can interfere with XAC and is able to suppress endothelial cell activation in this ex vivo perfusion model, thus representing a potential candidate as an adjuvant immunosuppressive drug. Reference: 1. BÜhler L, Basker M, Alwayn IPet al. Coagulation and thrombotic disorders associated with pig organ and hematopoietic cell transplantation in nonhuman primates. Transplantation 2000; 9: 1323–1331.     

High‐sensitive Troponin T measurements early after heart transplantation predict short‐ and long‐term survival

Following heart transplantation, cardiac biomarkers remain elevated for several weeks eventually as a result of membrane leakage of the donor organ. We now test the predictive power of blood levels of troponin T (TNT) measured by the new hsTNT assay (Roche Diagnostics, Roche Diagnostics, Mannheim, Germany) early after heart transplantation. TNT was determined in 141 cardiac allograft recipients and 40 controls. Our findings demonstrate that patients who died within the first year after transplantation had significantly higher median hsTNT serum levels 6 weeks after transplantation (156 ng/l ± 203 vs. 29 ng/l ± 21, P = 0.0002). Using ROC analysis, a serum hsTNT concentration of 33.55 ng/l 6 weeks after transplantation was found to be the best cutoff to predict death at 1 year (HR 0.16, 95%CI:0.05–0.46, P = 0.001) with a sensitivity of 90.91% and a specificity of 70.97%. In addition, survival at 5 years (HR 0.15, 95% CI 0.06–0.35, P < 0.0001) was significantly better among patients below that cutoff value. In multivariate analysis, hsTNT serum level 6 weeks after transplantation emerged as an independent predictor for first‐year mortality (hsTNT–HR 0.90, 95% CI: 0.81–1.00, P = 0.03). Cardiac troponin T concentrations early after transplantation as measured with a highly sensitive assay represent a strong and independent risk predictor of death after heart transplantation.     

Oxidative stress in patients treated with continuous ambulatory peritoneal dialysis (CAPD) and the significant role of vitamin C and E supplementation

Purpose

Chronic renal failure patients undergoing peritoneal dialysis (PD) are characterized by increased oxidative stress (OS), which is associated with enhanced cardiovascular risk. Moreover, oxidative stress also contributes to peritoneal membrane changes and ultrafiltration failure. The aim of this study was to evaluate OS in PD patients and the effect of treatment with ascorbic acid and α-tocopherol.

Methods

Plasma, erythrocyte, urine, and peritoneal effluent samples from 20 patients on PD were evaluated for glutathione peroxidase and superoxide dismutase activity, total antioxidant capacity (TAC) and malondialdehyde (MDA) levels, as well as protein carbonyl formation, before and after administration of vitamin C, alone or in combination with vitamin E, in comparison with 10 apparently healthy control individuals.

Results

All studied markers showed enhanced OS in the PD group, compared to controls. The supplementation of vitamin C and E resulted in improvements of all the OS markers, as indicated by increased erythrocyte antioxidant enzymes activity and TAC levels, as well as decreased MDA concentration and carbonyl compound formation.

Conclusions

The oral supplementation of antioxidant vitamins C and E, in combination, can lead to decreased OS, thus providing a useful and cost-effective therapeutic option in PD patients.     

Systematic Review of Adrenalectomy and Lymph Node Dissection in Locally Advanced Renal Cell Carcinoma

Context

Controversy remains over whether adrenalectomy and lymph node dissection (LND) should be performed concomitantly with radical nephrectomy (RN) for locally advanced renal cell carcinoma (RCC) cT3–T4N0M0.

Objective

To systematically review all relevant literature comparing oncologic, perioperative, and quality-of-life (QoL) outcomes for locally advanced RCC managed with RN with or without concomitant adrenalectomy or LND.

Evidence acquisition

Relevant databases were searched up to August 2012. Randomised controlled trials (RCTs) and comparative studies were included. Outcome measures were overall survival, QoL, and perioperative adverse effects. Risks of bias (RoB) were assessed using Cochrane RoB tools. Quality of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation approach.

Evidence synthesis

A total of 3658 abstracts and 252 full-text articles were screened. Eight studies met the inclusion criteria: six LNDs (one RCT and five nonrandomised studies [NRSs]) and two adrenalectomies (two NRSs). RoB was high across the evidence base, and the quality of evidence from outcomes ranged from moderate to very low. Meta-analyses were not undertaken because of diverse study designs and data heterogeneity. There was no significant difference in survival between the groups, even though 5-yr overall survival appears better for the RN plus LND group compared with the no-LND group in one randomised study. There was no evidence of a difference in adverse events between the RN plus LND and no-LND groups. No studies reported QoL outcomes. There was no evidence of an oncologic difference between the RN with adrenalectomy and RN without adrenalectomy groups. No studies reported adverse events or QoL outcomes.

Conclusions

There is insufficient evidence to draw any conclusions on oncologic outcomes for patients having concomitant LND or ipsilateral adrenalectomy compared with patients having RN alone for cT3–T4N0M0 RCC. The quality of evidence is generally low and the results potentially biased. Further research in adequately powered trials is needed to answer these questions.     

Nodular giant cell tumour of the tendon sheath of the hand: analysis of eighty-four cases—diagnostic decisions and outcome

Introduction

The giant cell tumour of the tendon sheath (GCTTS) of the hand is a benign tumour of unknown origin. The clinical diagnosis is supported by preoperative imaging. But the ideal imaging methods necessary for the diagnosis, preoperative planning and total tumour resection are still debated. Standard treatment is surgical resection with histological confirmation.

Methods

We followed up 84 patients who were operated upon for a histologically confirmed nodular type GCTTS for an average of 4.7 years (range four to eight). The preoperative symptoms and radiological findings of X-ray, ultrasound and MRI were reviewed and the surgeon asked for their impact on the surgical procedure.

Results

The average age at operation was 50.9 years, 65.5 % of the patients were female and 61.9 % of the lesions were located on the palmar aspect. Most tumours were found on the first three fingers. Two patients had tumours at two separate sites (2.4 %). After an average follow up of 31.5 months two recurrences were observed (2.4 %). In addition to X-ray and ultrasound, the preoperative findings of the MRI had no influence on the surgical procedure.

Conclusion

Our data on the nodular GCTTS are in accordance with published data concerning the age distribution, gender distribution, and localisation. No soft-tissue imaging method is superior for the diagnosis of nodular GCTTS or for the preoperative planning. A preoperative MRI may not be necessary as clinical and ultrasound examination are sufficient. To exclude bony erosions, a preoperative X-ray is necessary.