Combination of Single- and Paired-Pulse Somatosensory Evoked Potentials in Ischemic Monitoring: Preliminary Investigation in Carotid Endarterectomy.

Introduction Severe ischemia induces cerebral excitability imbalance before completion of infarct. To investigate the clinical availability of this imbalance with ischemic monitoring, paired-pulse somatosensory evoked potentials (SEPs) were performed in conjunction with conventional SEPs during carotid endarterectomy. Methods For carotid endarterectomy patients with hemodynamic deficits of the middle cerebral artery area (n = 34), the excitability imbalances (Q) were measured by paired-pulse SEPs, wherein the second response (A2) was divided by the first (A1; Q = A2/A1). Regional cerebral saturation (rSO2) was also measured. Occlusion was performed twice using shunting. Results Each carotid occlusion induced a significant decrease in mean A1 and rSO2, and an increase in mean Q values (p < 0.001), which returned to the baseline level after occlusion. While neuronal imbalances were mostly transient, persistently increased Q values were observed in four cases (11.8%), all indicating postoperative abnormalities in diffusion-weighted magnetic resonance imaging (100%). Meanwhile, A1 detected the postoperative abnormality in only one case (25%). Preoperative Q values at the time of surgery were significantly higher in symptomatic patients having the upper limb deficits than those without (p < 0.01), indicating persistent or permanent imbalances. Conclusion Paired-pulse SEPs reliably identified transient, persistent or permanent neuronal imbalances, depending on the ischemic severity. These preliminary results indicated that paired-pulse SEPs, in combination with conventional SEPs (A1), may offer better ischemic monitoring.

Acute subdural hematoma requiring surgery in the subacute or chronic stage.

The aim of this study was to clarify the clinical characteristics and pathophysiology of conservatively treated cases of acute subdural hematoma (ASDH) that ultimately require surgery in the subacute or chronic stage, and devise an appropriate form of management for them. A total of 50 patients with ASDH were admitted to our institution during a 5-year period. Hematoma removal in the subacute or chronic stage was performed in 8 patients. The ASDH had been caused by a fall in 5 patients. Five patients had been treated with antiplatelet agents. Fluid-attenuated inversion recovery magnetic resonance (MR) imaging demonstrated an irregularly shaped hematoma with gyrus patterns in 4 of 5 patients. Diffusion-weighted MR imaging demonstrated a two-layered hematoma structure in 3 of 4 patients. The hematoma was removed via a craniotomy, a small craniotomy, and a burr hole in 1, 1, and 6 patients, respectively. At surgery in the craniotomy case, a solid clot was located beneath the dura, and a liquid hematoma was located close to the brain. After hematoma removal, no inner membrane was observed on the brain surface. One patient had typical chronic subdural hematoma in the subacute stage, and 2 patients had so-called subacute subdural hematoma (SASDH) in the chronic stage. Although the majority of such cases can be treated by burr-hole surgery, a small craniotomy or craniotomy ought to be considered as a further surgical option if SASDH is diagnosed on the basis of clinical and radiological data, especially diffusion-weighted MR imaging.

Proposal for Japanese encephalitis surveillance using captured invasive mongooses under an eradication project on Okinawa Island, Japan.

A project to eradicate invasive small Asian mongooses (Herpestes javanicus) is underway to conserve the unique ecosystem of Okinawa Island, Japan. In the present study, we tried to elucidate whether the mongoose is a host of Japanese encephalitis virus (JEV) and to evaluate the reliability of surveillance of Japanese encephalitis (JE) using this species. Culex tritaeniorhynchus, the main vector mosquito of JEV, feeds on the mongoose. Eighty-five (35.4%) of 240 wild small Asian mongooses captured between 2001 and 2005 had neutralizing antibodies against more than one of four JEV strains. Prevalence rates of JEV antibodies tended to increase with body weight and length of the animals. One of three sentinel mongooses showed a temporal change in antibody titer. These results indicate that the small Asian mongooses on Okinawa Island are sensitive to JEV. From the antibody titers and the locations of capture, the JEV active area was clarified. We propose that surveillance of JE using mongooses captured under the eradication program is reliable.

Aspirin inhibits Chlamydia pneumoniae-induced NF-kappa B activation, cyclo-oxygenase-2 expression and prostaglandin E2 synthesis and attenuates chlamydial growth.

Infection with Chlamydia pneumoniae has been implicated as a potential risk factor for atherosclerosis. This study was designed to investigate the mechanisms of the anti-chlamydial activity of aspirin. A reporter gene assay for NF-kappa B activity, immunoblot analysis for cyclo-oxygenase (COX)-2 and radioimmunoassay for prostaglandin E(2) (PGE(2)) were performed. Following infection of HEp-2 cells with C. pneumoniae, NF-kappa B was activated, COX-2 was induced and PGE(2) was elevated. Aspirin inhibited NF-kappa B activation at a concentration of 0.1 mM, partially inhibited COX-2 induction and blocked PGE(2) synthesis completely. In addition, high doses of aspirin (1 and 2 mM) inhibited chlamydial growth in HEp-2 cells, decreasing the number and size of inclusion bodies; this effect could be overcome by adding tryptophan to the culture. Indomethacin also blocked the synthesis of PGE(2), but had no effect on COX-2 expression or chlamydial growth. These results indicate that aspirin not only has an anti-inflammatory activity through prevention of NF-kappa B activation but also has anti-chlamydial activity at high doses, possibly through depletion of tryptophan in HEp-2 cells.