Decreased infarct size after focal cerebral ischemia in mice chronically infected with Toxoplasma gondii

To determine whether Toxoplasma gondii infection could modify biological phenomena associated with brain ischemia, we investigated the effect of permanent middle cerebral artery occlusion (MCAO) on neuronal survival, inflammation and redox state in chronically infected mice. Infected animals showed a 40% to 50% decrease of infarct size compared with non-infected littermates 1, 4 and 14 days after MCAO. The resistance of infected mice may be associated with increased basal levels of anti-inflammatory cytokines and/or a marked reduction of the MCAO-related brain induction of two pro-inflammatory cytokines, tumor necrosis factor-alpha and interferon-gamma (IFNgamma). In addition, potential anti-inflammatory/neuroprotective factors such as nerve growth factor, suppressor of cytokine signaling-3, superoxide dismutase activity, uncoupling protein-2 and glutathione (GSH) were upregulated in the brain of infected mice. Consistent with a role of GSH in central cytokine regulation, GSH depletion by diethyl maleate inhibited Toxoplasma gondii lesion resistance by increasing the proinflammatory cytokine IFNgamma brain levels. Overall, these findings indicate that chronic toxoplasmosis decisively influences both the inflammatory molecular events and outcome of cerebral ischemia.

Human temporal bones versus mechanical model to evaluate three middle ear transducers

A life-size mechanical middle ear model and human temporal bones were used to evaluate three different middle ear transducers for implantable hearing aids: the driving rod transducer (DRT), the floating mass transducer (FMT) or vibrant sound bridge, and the contactless transducer (CLT). Results of the experiments with the mechanical model were within the range of the results for human temporal bones. However, results with the mechanical model showed better reproducibility. The handling of the mechanical model was considerably simpler and less time-consuming. Systematic variations of mounting parameters showed that the angle of the rod has virtually no effect on the output of the DRT, the mass loading on the cable of the FMT has a larger impact on the output than does the tightness of crimping, and the output level of the CLT can be increased by 10 dB by optimizing the mounting parameters.

Automated, compliant, high-flow common carotid to middle cerebral artery bypass

The authors describe the use of the Cardica C-Port xA Distal Anastomosis System to perform an automated, high-flow extracranial-intracranial bypass. The C-Port system has been developed and tested in coronary artery bypass surgery for rapid distal coronary artery anastomoses. Air-powered, it performs an automated end-to-side anastomosis within seconds by nearly simultaneously making an arteriotomy and inserting 13 microclips into the graft and recipient vessel. Intracranial use of the device was first simulated in a cadaver prepared for microsurgical anatomical dissection. The authors used this system in a 43-year-old man who sustained a subarachnoid hemorrhage after being assaulted and was found to have a traumatic pseudoaneurysm of the proximal intracranial internal carotid artery. The aneurysm appeared to be enlarging on serial imaging studies and it was anticipated that a bypass would probably be needed to treat the lesion. An end-to-side bypass was performed with the C-Port system using a saphenous vein conduit extending from the common carotid artery to the middle cerebral artery. The bypass was demonstrated to be patent on intraoperative and postoperative arteriography. The patient had a temporary hyperperfusion syndrome and subsequently made a good neurological recovery. The C-Port system facilitates the performance of a high-flow extracranial-intracranial bypass with short periods of temporary arterial occlusion. Because of the size and configuration of the device, its use is not feasible in all anatomical situations that require a high-flow bypass; however it is a useful addition to the armamentarium of the neurovascular surgeon.

Circulating oxidized low-density lipoprotein (LDL) is associated with risk factors of the metabolic syndrome and LDL size in clinically healthy 58-year-old men (AIR study).

OBJECTIVES Hypothetically the atherogenic effect of the metabolic syndrome may be mediated through the increased occurrence of small LDL-particles which are easily modified to atherogenic oxidized LDL (ox-LDL). The aim of this study was to test this concept by examining the association between circulating ox-LDL, LDL-particle size, and the metabolic syndrome. DESIGN AND RESULTS A population-based sample of clinically healthy 58-year-old men (n = 391) was recruited. Ox-LDL was measured by ELISA (specific monoclonal antibody, mAb-4E6) and LDL-particle size by gradient gel electrophoresis. The results showed that ox-LDL significantly correlated to factors constituting the metabolic syndrome; triglycerides (r = 0.43), plasma insulin (r = 0.20), body mass index (r = 0.20), waist-to-hip ratio (r = 0.21) and HDL (r = -0.24); (P < 0.001). Ox-LDL correlated also to LDL-particle size (r = -0.42), Apo-B (r = 0.70), LDL (r = 0.65); (P < 0.001) and, furthermore, with Apo A-1 (r = -0.13) and heart rate (r = 0.13); (P < 0.01). CONCLUSION The metabolic syndrome was accompanied by high plasma ox-LDL concentrations compared with those without the syndrome. Ox-LDL levels were associated with most of the risk factors constituting the metabolic syndrome and was, in addition related to small LDL-particle size. To our knowledge the present study is the first one to demonstrate that circulating ox-LDL levels are associated with small LDL-particle size in a population representative sample of clinically healthy middle-aged men. The high degree of intercorrelation amongst several factors makes it difficult to clarify the independent role of any specific factor.