Surgical treatment of primary malignant tumours of the distal tibia: clinical outcome and reconstructive strategies.

AIMS: We retrospectively report our experience of managing 30 patients with a primary malignant tumour of the distal tibia; 25 were treated by limb salvage surgery and five by amputation. We compared the clinical outcomes of following the use of different methods of reconstruction. PATIENTS AND METHODS: There were 19 male and 11 female patients. The mean age of the patients was 19 years (6 to 59) and the mean follow-up was 5.1 years (1.25 to 12.58). Massive allograft was used in 11 patients, and autograft was used in 14 patients. The time to union, the survival time of the reconstruction, complication rate, and functional outcomes following the different surgical techniques were compared. The overall patient survival was also recorded. RESULTS: Out of 14 patients treated with an autograft, 12 (86%) achieved union at both the proximal and distal junctions. The time to union at both junctions of the autograft was significantly shorter than in those treated with an allograft (11.1 vs 17.2 months, p = 0.02; 9.5 vs 16.2 months, p = 0.04). The complication rate of allograft reconstruction was 55%. The five patients treated with an amputation did not have a complication. Out of the 25 patients who were treated with limb salvage, three (12%) developed local recurrence and underwent amputation. The mean functional Musculoskeletal Tumor Society (MSTS) score after autograft reconstruction was higher than after allograft reconstruction (81% vs 67%; p = 0.06), and similar to that after amputation (81% vs 82%; p = 0.82). The two- and five-year overall rates of survival were 83% and 70%, respectively. CONCLUSIONS: This consecutive case series supports the safety of limb salvage and the effectiveness of biological reconstruction after the resection of a primary tumour of the distal tibia. Autograft might be a preferable option. In some circumstances, below-knee amputation remains a valid option.

MicroRNA-195 induced apoptosis in hypoxic chondrocytes by targeting hypoxia-inducible factor 1 alpha.

OBJECTIVE: The chondrocytes, the resident cells of cartilage, are maintained and take effects in the whole life upon chronic hypoxic exposure, which hypoxia-inducible factor 1 alpha (HIF-1α) play pivotal roles in response to. Dysregulation of some microRNA (miRNAs) have also been identified to be involved in hypoxia-related physiologic and pathophysiologic responses in some tissues or cell lines. However, the mechanism of miRNAs reponse to hypoxia remain largely unknown in chondrocytes, including the microRNA-195 (miR-195). AIM To investigate the effects of microRNAs (miRNAs) and hypoxia-inducible factor 1 alpha (HIF-1α) on chondrocytes in physiologic environment. MATERIALS AND METHODS: We compared the expression of miR-195 and HIF-1α mRNA on hypoxia with that on normoxia in ATDC 5 cells by qRT-PCR. Further experiments was performed to confirmed the relationships of miR-195 and HIF-1α by bioinformatics analysis and dual reporter gene assay. we also assessed the effect of miR-195 on apoptosis in hypoxic ATDC 5 cells by transfect with miR-195 mimics. RESULTS: It was found the downregulated miR-195 and upregulated HIF-1α were present in hypoxic ATDC 5 cells. miR-195 negatively regulated HIF-1α by targeting its 3'-untranslated region. Moreover, the founding indicated miR-195 greatly increased apoptosis and downregulated HIF-1α mRNA occurred simultaneously in hypoxic chondrocytes. CONCLUSIONS: We concluded that miR-195 induced apoptosis in hypoxic chondrocytes by directly targeting HIF-1α.

Neutrophil inhibition contributes to cardioprotection by postconditioning.

BACKGROUND: Postconditioning (postcon) reduces infarct size, myocardial superoxide ((•)O(2)) generation, and neutrophil (PMN) accumulation. It is unknown whether inhibition of PMNs influence cardioprotection by postcon. The present study tested the following hypotheses: (1) myocardial salvage by postcon is modified by inhibition of PMNs and (2) postcon directly inhibits PMN (•)O(2) generation. METHODS: For hypothesis 1, a deductive approach was used to determine infarct size in vivo with and without PMNs in rats, and for hypothesis 2, blood sampled from the anterior interventricular vein (AIV) in a canine model was used. Protocol 1: anesthetized rats, subjected to 30 min of coronary artery occlusion and 3 h of reperfusion, were randomized to control (n = 13), postcon (n = 13), PMN-depletion: (n = 9), and postcon in PMN-depleted rats (n = 9). Protocol 2: blood was sampled at baseline, 2 h and 24 h from the AIV, draining the area at risk (AAR) in anesthetized dogs with 60 min coronary occlusion ± postcon; whole blood was analyzed for (•)O(2) by luminol-enhanced chemiluminescence. RESULTS: Postcon and PMN depletion reduced infarct size (42.6 ± 2.1%, P < 0.05 vs. control, and 43.9 ± 3.0%, P < 0.05 vs. control, respectively) vs. control (58.8 ± 0.9%), with no further decrease with postcon in PMN-depleted rats (37.2 ± 2.9%, P = 0.34 vs. postcon). PMN accumulation in AAR was less in postcon (21.2 ± 0.3%, P < 0.05 vs. control) and PMN-depleted (9.4 ± 0.3%, P < 0.05 vs. control) vs. control (30.5 ± 1.2%), with a further decrease in the postcon + PMN depletion group (5.4 ± 0.6%, P < 0.05 vs. control). In dogs, (•)O(2) release by PMNs increased at 2 h and 24 h of R, which was reduced to baseline levels by postcon. CONCLUSIONS: These data imply PMN involvement in cardioprotection by postconditioning.

Autophagy is involved in traumatic brain injury-induced cell death and contributes to functional outcome deficits in mice.

Previous data demonstrate that traumatic brain injury (TBI) activates autophagy, and increases microtubule-associated protein 1 light chain 3 (LC3) immunostaining mainly in neurons. However, the role of autophagy in traumatic brain damage remains elusive. The aim of the present study was to investigate the autophagic mechanisms participating in traumatic brain injury. The autophagy inhibitors 3-methyladenine (3-MA) and bafliomycin A1 (BFA) were administered with a single i.c.v. injection before TBI. We first examined the protein levels of Beclin-1 and LC3 II, which have been found to promote autophagy previously. Immunoblotting analysis showed that 3-MA pretreatment reduced post-TBI Beclin-1 and LC3-II levels, and maintained p62/SQSTM1 (p62) levels. In addition, double immunolabeling showed that the increased punctate LC3-II dots colocalizing with Propidium Iodide (PI)-stained nuclei at 24 h after injury, were partially inhibited by 3-MA pretreatment. Furthermore, inhibition of autophagy could reduce TBI-induced cell injury assessed with i.p. injection of PI and lesion volume, and attenuate behavioral outcome evaluated by motor test and Morris water maze. The neuroprotective effects were associated with an inhibition on TBI-induced up-regulation of LC3, Beclin-1, cathepsin B, caspase-3 and the Beclin-1/Bcl-2 ratio. Taken together, these data imply that the autophagy pathway is involved in the pathophysiologic responses after TBI, and inhibition of this pathway may help attenuate traumatic damage and functional outcome deficits.

Blockade of the RAS increases plasma adiponectin in subjects with metabolic syndrome and enhances differentiation and adiponectin expression of human preadipocytes.

AIMS: This observational study aimed to investigate the effects of renin-angiotensin system (RAS) blockers on plasma adiponectin in subjects with metabolic syndrome (Mets) and differentiation, adiponectin expression of human omental (OM) and subcutaneous (SC) preadipocytes. METHODS: Fifty-three patients with Mets were treated with angiotensin converting enzyme inhibition (ACEI), angiotensin II receptor blocker (ARB) or nothing, lipid profile and adiponetin were measured. OM and SC preadipocytes were obtained from sixteen normal non-menopausal women undergoing elective abdominal surgery and subsequently differentiated in the presence of ACE, ARB or thiazolidinedione (TZD). Differentiation was assessed using a number of biochemical and function parameters. RESULTS: Plasma adiponectin was increased dramatically as a result of ACEI and ARB treatment. Most of the metabolic and differentiating parameters were improved significantly by RAS blockers or TZD. Compared with TZD, RAS blockers have stronger effects on omental preadipocytes in differentiation and insulin sensitivity. The improvement of adiponectin mRNA expression was significantly greater in ARB-treated omental preadipocytes compared with TZD-treated ones. CONCLUSION: These results suggest that adiponectin may serve as potential therapeutic targets of ACEI and ARB for treating the Mets and its related complications. It also suggests a potential benefit of RAS blockers on Mets with characteristic visceral obesity.

Remote postconditioning. Brief renal ischemia and reperfusion applied before coronary artery reperfusion reduces myocardial infarct size via endogenous activation of adenosine receptors.

OBJECTIVES: A series of brief coronary artery reperfusions and reocclusions applied during the early minutes of coronary artery reflow ("postconditioning") attenuates reperfusion injury. However, it is not known whether brief ischemia-reperfusion applied to a distant organ at the onset of myocardial reperfusion (i.e. "remote postconditioning", remote PostC) reduces infarct size in the reperfused myocardium. In an in vivo anesthetized rat model of myocardial infarction induced by coronary artery occlusion and reperfusion, this study tested the hypothesis that remote postC induced by a single 5 minute episode of renal artery (RA) occlusion and reperfusion applied immediately before the onset of coronary artery reperfusion protects the myocardium from reperfusion injury by mechanisms involving endogenous adenosine receptor activation. METHODS: All rats were subjected to a total of 30 minutes of left coronary artery occlusion (LCAO) and 3 hours of reperfusion. The rats were randomized to one of six groups: 1) CONTROL: LCAO and reperfusion only with no other intervention; 2) Remote PostC: after 24 minutes of LCAO the RA was occluded for 5 minutes and released 1 min before coronary artery reperfusion; 3) Permanent RA occlusion: the RA was permanently occluded after 24 minutes LCAO continuing to the end of reperfusion; 4) Delayed Remote PostC: after 26 minutes LCAO the RA was occluded for 5 minutes, and its release was delayed until 1 min after coronary artery reperfusion; 5) CON + SPT: rats with LCAO and reperfusion received 10 mg/kg IV of the non-selective adenosine receptor antagonist 8-sulfophenyl theophylline [SPT] administered 5 minutes before coronary artery reperfusion; and 6) Remote PostC + SPT: after 24 minutes of LCAO the RA was occluded for 5 minutes and released 1 minute before coronary artery reperfusion in the presence of 10 mg/kg SPT given 5 min before coronary artery reperfusion. RESULTS: Myocardial infarct size (percentage necrosis/area at risk, mean +/- SEM) was reduced by 50% in Remote PostC (25 +/- 4%) compared to CONTROL (49 +/- 4%, p = 0.003), consistent with a reduction in plasma CK activity (44 +/- 5 vs. 67 +/- 6 U/ml, p = 0.023). In contrast, permanent RA occlusion before LCAO and reperfusion failed to reduce myocardial infarct size (47 +/- 5%) vs CONTROL. Delaying the release of the RA occlusion (delayed Remote PostC) abrogated the myocardial infarct reduction observed with Remote PostC (48 +/- 6%). SPT alone had no effect on infarct size (47 +/- 4% in CON + SPT vs. 49 +/- 4% in CON); however, Remote PostC+SPT abrogated the myocardial infarct size reduction in Remote PostC (50 +/- 3% in Remote PostC + SPT vs. 25 +/- 4% in Remote PostC). CONCLUSIONS: Remote renal postconditioning applied immediately before the onset of coronary artery reperfusion provides potent myocardial infarct size reduction likely exerted during the first minutes of coronary artery reperfusion. This inter-organ remote postconditioning phenomenon is likely mediated in part by release of adenosine by the ischemic-reperfused kidney and subsequent activation of adenosine receptors.

Postconditioning--A new link in nature's armor against myocardial ischemia-reperfusion injury.

Reperfusion injury is a complex process involving several cell types (endothelial cells, neutrophils, and cardiomyocytes), soluble proinflammatory mediators, oxidants, ionic and metabolic dyshomeostasis, and cellular and molecular signals. These participants in the pathobiology of reperfusion injury are not mutually exclusive. Some of these events take place during the very early moments of reperfusion, while others, seemingly triggered in part by the early events, are activated within a later timeframe. Postconditioning is a series of brief mechanical interruptions of reperfusion following a specific prescribed algorithm applied at the very onset of reperfusion. This algorithm lasts only from 1 to 3 minutes depending on species. Although associated with re-occlusion of the coronary artery or re-imposition of hypoxia in cell culture, the reference to ischemia has been dropped. Postconditioning has been observed to reduce infarct size and apoptosis as the "end games" in myocardial therapeutics; salvage of infarct size was similar to that achieved by the gold standard of protection, ischemic preconditioning. The cardioprotection was also associated with a reduction in: endothelial cell activation and dysfunction, tissue superoxide anion generation, neutrophil activation and accumulation in reperfused myocardium, microvascular injury, tissue edema, intracellular and mitochondrial calcium accumulation. Postconditioning sets in motion triggers and signals that are functionally related to reduced cell death. Adenosine has been implicated in the cardioprotection of postconditioning, as has e-NOS, nitric oxide and guanylyl cyclase, opening of K(ATP) channels and closing of the mitochondrial permeability transition pore. Cardioprotection by postconditioning has also been associated with the activation of intracellular survival pathways such as ERK1/2 and PI3 kinase - Akt pathways. Other pathways have yet to be identified. Although many of the pathways involved in postconditioning have also been identified in ischemic preconditioning, some may not be involved in preconditioning (ERK1/2). The timing of action of these pathways and other mediators of protection in postconditioning differs from that of preconditioning. In contrast to preconditioning, which requires a foreknowledge of the ischemic event, postconditioning can be applied at the onset of reperfusion at the point of clinical service, i.e. angioplasty, cardiac surgery, transplantation.

Interleukin-2 gene therapy of chronic neuropathic pain.

Previous research has revealed an antinociceptive (analgesic) effect of interleukin-2 (IL-2) in central and peripheral nervous systems. Unfortunately IL-2 is very short-lived in vivo, so it is impractical to apply IL-2 for analgesia in clinic. This study was performed to evaluate the effect of intrathecal delivery of human IL-2 gene on rat chronic neuropathic pain induced by chronic constriction injury of the sciatic nerve. Human IL-2 cDNA was cloned into pcDNA3 containing a cytomegalovirus promoter. The paw-withdrawal latency induced by radiant heat was used to measure the pain threshold. The results showed that recombinant human IL-2 had a dose-dependent antinociceptive effect, but that this only lasted for 10-25 min. The pcDNA3-IL-2 or pcDNA3-IL-2/lipofectamine complex in contrast also showed dose-dependent antinociceptive effects, but these reached a peak at day 2-3 and were maintained for up to 6 days. Liposome-mediated pcDNA3-IL-2 produced a more powerful antinociceptive effect than pcDNA3-IL-2 alone. The paw-withdrawal latencies were not affected by control treatments such as vehicle, lipofectamine, pcDNA3, or pcDNA3-lipofectamine. In the experimental groups, human IL-2 mRNA was detected by reverse transcription-polymerase chain reaction in the lumbar spinal pia mater, dorsal root ganglion, sciatic nerve, and spinal dorsal horn, but not in gastrocnemius muscle. The expressed IL-2 profile detected by western blot coincided with its mRNA profile except it was present in the spinal dorsal horn at a higher level. Furthermore, human IL-2 assayed by enzyme-linked immunosorbent assay in cerebrospinal fluid could still be detected at day 6, but lower than day 3. The antinociceptive effect of pcDNA3-IL-2 could be blocked by naloxone, showing some relationship of the antinociceptive effect produced by IL-2 gene to the opioid receptors. It is hoped that the new delivery approach of a single intrathecal injection of the IL-2 gene described here may be of some practical use as a part of a gene therapy for treating neuropathic pain.