Effects of isolated and combined exposure of the brain and lungs to a laser-induced shock wave(s) on physiological and neurological responses in rats

Blast-induced traumatic brain injury (bTBI) has been suggested to be caused by direct head exposure and by torso exposure to a shock wave (thoracic hypotheses). However, it is unclear how torso exposure affects the brain in real-time. This study applied a mild-impulse laser-induced shock wave(s) (LISW[s]) only to the brain (Group 1), lungs (Group 2), or to the brain and lungs (Group 3) in rats. Since LISWs are unaccompanied by a dynamic pressure in principle, the effects of acceleration can be excluded, allowing analysis of the pure primary mechanism. For all rat groups, real-time monitoring of the brain and systemic responses were conducted for up to 1 h postexposure and motor function assessments for up to 7 days postexposure. As previously reported, brain exposure alone caused cortical spreading depolarization (CSD), followed by long-lasting hypoxemia/oligemia in the cortices (Group 1). It was found that even LISW application only to the lungs caused prolonged hypoxemia and mitochondrial dysfunction in the cortices (Group 2). Importantly, CSD and mitochondrial dysfunction were significantly exacerbated by combined exposure (Group 3) compared with those caused by brain exposure alone (Group 1). Motor dysfunction was observed in all groups, but their time courses depended on the exposure schemes. Rats of Group 1 exhibited the most evident motor dysfunction at 1 day postexposure, and it did not change much for up to 7 days postexposure. Alternatively, two groups of rats with lung exposure (Groups 2&3) exhibited continuously aggravated motor functions for up to 7 days postexposure, suggesting different mechanisms for motor dysfunction caused by brain exposure and that caused by lung exposure. As for the reported thoracic hypotheses, our observations seem to support the volumetric blood surge and vago-vagal reflex. Overall, the results of this study indicate the importance of the torso guard to protect the brain.

Behavioral and Histopathological Impairments Caused by Topical Exposure of the Rat Brain to Mild-Impulse Laser-Induced Shock Waves: Impulse Dependency

Although an enormous number of animal studies on blast-induced traumatic brain injury (bTBI) have been conducted, there still remain many uncertain issues in its neuropathology and mechanisms. This is partially due to the complex and hence difficult experimental environment settings, e.g., to minimize the effects of blast winds (tertiary mechanism) and to separate the effects of brain exposure and torso exposure. Since a laser-induced shock wave (LISW) is free from dynamic pressure and its energy is spatially well confined, the effects of pure shock wave exposure (primary mechanism) solely on the brain can be examined by using an LISW. In this study, we applied a set of four LISWs in the impulse range of 15–71 Pa·s to the rat brain through the intact scalp and skull; the interval between each exposure was ~5 s. For the rats, we conducted locomotor activity, elevated plus maze and forced swimming tests. Axonal injury in the brain was also examined by histological analysis using Bodian silver staining. Only the rats with exposure at higher impulses of 54 and 71 Pa·s showed significantly lower spontaneous movements at 1 and 2 days post-exposure by the locomotor activity test, but after 3 days post-exposure, they had recovered. At 7 days post-exposure, however, these rats (54 and 71 Pa·s) showed significantly higher levels of anxiety-related and depression-like behaviors by the elevated plus maze test and forced swimming test, respectively. To the best of the authors' knowledge, there have been few studies in which a rat model showed both anxiety-related and depression-like behaviors caused by blast or shock wave exposure. At that time point (7 days post-exposure), histological analysis showed significant decreases in axonal density in the cingulum bundle and corpus callosum in impulse-dependent manners; axons in the cingulum bundle were found to be more affected by a shock wave. Correlation analysis showed a statistically significant correlation between the depression like-behavior and axonal density reduction in the cingulum bundle. The results demonstrated the dependence of behavior deficits and axonal injury on the shock wave impulse loaded on the brain.

Multispectral imaging of cortical vascular and hemodynamic responses to a shock wave: observation of spreading depolarization and oxygen supply-demand mismatch

Blast-induced traumatic brain injury has been a recent major concern in neurotraumatology. However, its pathophysiology and mechanism are not understood partly due to insufficient information on the brain pathophysiology during/immediately after shock wave exposure. We transcranially applied a laser-induced shock wave (LISW, ∼19  Pa  ·  s) to the left frontal region in a rat and performed multispectral imaging of the ipsilateral cortex through a cranial window (n  =  4). For the spectral data obtained, we conducted multiple regression analysis aided by Monte Carlo simulation to evaluate vascular diameters, regional hemoglobin concentration (rCHb), tissue oxygen saturation (StO2), oxygen extraction fraction, and light-scattering signals as a signature of cortical spreading depolarization (CSD). Immediately after LISW exposure, rCHb and StO2 were significantly decreased with distinct venular constriction. CSD was then generated and was accompanied by distinct hyperemia/hyperoxemia. This was followed by oligemia with arteriolar constriction, but it soon recovered (within ∼20  min). However, severe hypoxemia was persistently observed during the post-CSD period (∼1  h). These observations indicate that inadequate oxygen supply and/or excessive oxygen consumption continued even after blood supply was restored in the cortex. Such a hypoxemic state and/or a hypermetabolic state might be associated with brain damage caused by a shock wave.

Subcutaneous Extension of Parasagittal Atypical Meningioma Through Parietal Foramen

Meningiomas extended to the scalp without any bony changes are rare. A 79-year-old man presented with a large subcutaneous mass in the midline parieto-occipital region and progressive right hemiparesis. The contrast-enhanced millimetric computed tomography scans of the head showed the intracranial parasagittal enhanced mass invading the superior sagittal sinus and the subcutaneous mass without any bony destructive, osteoblastic, or osteolytic changes. Under the operative microscope, no visible communication was found between the intracranial and extracranial mass lesions. Histopathologic examination of both intracranial and extracranial tumors demonstrated the same atypical meningioma (World Health Organization grade II). The possible route of extracranial extension of the tumor may be the sizable parietal foramen.

Near-infrared diffuse reflectance signals for monitoring spreading depolarizations and progression of the lesion in a male rat focal cerebral ischemia model

In ischemic stroke research, a better understanding of the pathophysiology and development of neuroprotection methods are crucial, for which in vivo imaging to monitor spreading depolarizations (SDs) and evolution of tissue damage is desired. Since these events are accompanied by cellular morphological changes, light-scattering signals, which are sensitive to cellular and subcellular morphology, can be used for monitoring them. In this study, we performed transcranial imaging of near-infrared (NIR) diffuse reflectance at ∼800 nm, which sensitively reflects light-scattering change, and examined how NIR reflectance is correlated with simultaneously measured cerebral blood flow (CBF) for a rat middle cerebral artery occlusion (MCAO) model. After MCAO, wavelike NIR reflectance changes indicating occurrence of SDs were generated and propagated around the ischemic core for ∼90 min, during which time NIR reflectance increased not only within the ischemic core but also in the peripheral region. The area with increased reflectance expanded with increase in the number of SD occurrences, the correlation coefficient being 0.7686 (n = 5). The area with increased reflectance had become infarcted at 24 hr after MCAO. The infarct region was found to be associated with hypoperfusion or no-flow response to SD, but hyperemia or hypoperfusion followed by hyperemia response to SD was also observed, and the regional heterogeneity seemed to be connected with the rat cerebrovasculature and hence existence/absence of collateral flow. The results suggest that NIR reflectance signals depicted early evolution of tissue damage, which was not seen by CBF changes, and enabled lesion progression monitoring in the present stroke model.

Hydrogen improves neurological function through attenuation of blood-brain barrier disruption in spontaneously hypertensive stroke-prone rats

Background

Enhanced oxidative stress occurs in spontaneously hypertensive stroke-prone rats (SHRSP), and is important in blood–brain barrier (BBB) disruption. Hydrogen can exert potent protective cellular effects via reduction in oxidative stress in various diseases. The present study investigated whether long-term hydrogen treatment can improve neurological function outcome in the SHRSP model, and the effects of hydrogen on BBB function, especially the oxidative stress and the activity of matrix metalloproteinases (MMPs) in this model. Fifty-six animals were randomly assigned to 2 groups and treated as follows: SHRSP treated with hydrogen-rich water (HRW) (HRW group, n = 28); and SHRSP treated with regular water (control group, n = 28). The effect of HRW on overall survival and neurological function, and the effects of HRW on reactive oxygen species, BBB function, and MMP activities were examined.

Results

HRW treatment improved neurological function and tended to improve overall survival but without significant difference. The numbers of bleeds and infarcts were lower in the cortex and hippocampus in the HRW group. The HRW group exhibited a significantly lower number of 8-hydroxy-2'-deoxyguanosine-positive cells and vessels of extravasated albumin in the hippocampus compared with the control group. MMP-9 activity was reduced in the hippocampus in the HRW group compared with the control group.

Conclusions

The present study suggests that ingestion of HRW can improve neurological function outcome in the SHRSP model. This beneficial effect may be due to attenuation of BBB disruption via reduction in reactive oxygen species and suppression of MMP-9 activity in the hippocampus.

Chronic subdural hematoma associated with moyamoya disease

Chronic subdural hematomas (SDHs) associated with non-operated moyamoya disease are extremely rare. A 68-year-old woman underwent burr-hole surgery for a right SDH, which resolved completely. On day 3, however, the patient suffered cerebral infarction in the right parietal lobe. Cerebral angiography demonstrated total occlusion of the bilateral internal carotid arteries with transdural anastomoses via branches of the right occipital artery and middle meningeal artery, feeding the left parietal cortex. A branch of the right middle meningeal artery passed near the burr hole, but was preserved. The patient was diagnosed of moyamoya disease. We thought that the main cause of chronic SDH might be the disruption of transdural anastomoses. Furthermore, we also hypothesized that we might have coagulated the small vessels of the transdural anastomoses which were undetectable by postoperative angiography, and that cerebral infarction might occur.

IgG4-Related Intracranial Hypertrophic Pachymeningitis : A Case Report and Review of the Literature

Hypertrophic pachymeningitis is an uncommon disorder that causes a localized or diffuse thickening of the dura mater. Recently, the possibility that IgG4-related sclerosing disease may underlie some cases of intracranial hypertrophic pachymeningitis has been suggested. We herein report the tenth case of IgG4-related intracranial hypertrophic pachymeningitis and review the previous literature. A 45-year-old male presented with left-sided focal seizures with generalization. Magnetic resonance imaging (MRI) revealed a diffuse thickening and enhancement of the right convexity dura matter and falx with focal nodularity. The surgically resected specimens exhibited the proliferation of fibroblast-like spindle cells and an infiltration of mononuclear cells, including predominantly plasma cells. The ratio of IgG4-positive plasma cells to the overall IgG-positive cells was 45% in the area containing the highest infiltration of plasma cells. On the basis of the above findings, IgG4-related sclerosing disease arising from the dura mater was suspected. IgG4-related sclerosing disease should be added to the pachymeningitis spectrum.

Decrease in plasma adiponectin level and increase in adiponectin immunoreactivity in cortex and hippocampus after traumatic brain injury in rats

AIM

Adiponectin plays an important role in the regulation of tissue inflammation. Recently, it has been reported that the plasma adiponectin levels in several acute illnesses decrease periodically, thus indicating that adiponectin may play a role in the inflammatory response in patients with acute illness. However, little is known about the effects of adiponectin following TBI. The aim of the present study was to examine the changes in the plasma adiponectin levels and the immunoreactivity of adiponectin in the brain after TBI.

MATERIAL AND METHODS

Adult male Sprague-Dawley rats were subjected to lateral fluid percussion injury using the Dragonfly device. Plasma adiponectin levels were determined by ELISA kit. Immunohistochemistry and Western blot analysis were performed to assess the immunoreactivity of adiponectin.

RESULTS

The plasma adiponectin levels gradually decreased and were significantly lower at 48 h and 72 h after injury than before injury. Immunohistochemistry and Western blot analysis showed that the adiponectin immunoreactivity was increased in the cerebral cortex at 24 hours after injury and in the hippocampus at 72 hours after injury.

CONCLUSION

Our findings suggest that adiponectin might participate in the pathophysiological process occurring after TBI.

Real-time optical diagnosis of the rat brain exposed to a laser-induced shock wave: observation of spreading depolarization, vasoconstriction and hypoxemia-oligemia

Despite many efforts, the pathophysiology and mechanism of blast-induced traumatic brain injury (bTBI) have not yet been elucidated, partially due to the difficulty of real-time diagnosis and extremely complex factors determining the outcome. In this study, we topically applied a laser-induced shock wave (LISW) to the rat brain through the skull, for which real-time measurements of optical diffuse reflectance and electroencephalogram (EEG) were performed. Even under conditions showing no clear changes in systemic physiological parameters, the brain showed a drastic light scattering change accompanied by EEG suppression, which indicated the occurrence of spreading depression, long-lasting hypoxemia and signal change indicating mitochondrial energy impairment. Under the standard LISW conditions examined, hemorrhage and contusion were not apparent in the cortex. To investigate events associated with spreading depression, measurement of direct current (DC) potential, light scattering imaging and stereomicroscopic observation of blood vessels were also conducted for the brain. After LISW application, we observed a distinct negative shift in the DC potential, which temporally coincided with the transit of a light scattering wave, showing the occurrence of spreading depolarization and concomitant change in light scattering. Blood vessels in the brain surface initially showed vasodilatation for 3-4 min, which was followed by long-lasting vasoconstriction, corresponding to hypoxemia. Computer simulation based on the inverse Monte Carlo method showed that hemoglobin oxygen saturation declined to as low as ∼35% in the long-term hypoxemic phase. Overall, we found that topical application of a shock wave to the brain caused spreading depolarization/depression and prolonged severe hypoxemia-oligemia, which might lead to pathological conditions in the brain. Although further study is needed, our findings suggest that spreading depolarization/depression is one of the key events determining the outcome in bTBI. Furthermore, a rat exposed to an LISW(s) can be a reliable laboratory animal model for blast injury research.

Low-level laser therapy for spinal cord injury in rats: effects of polarization

The effects of laser polarization on the efficacy of near-infrared low-level laser therapy for spinal cord injury (SCI) are presented. Rat spinal cords were injured with a weight-drop device, and the lesion sites were directly irradiated with a linearly polarized 808-nm diode laser positioned either perpendicular or parallel to the spine immediately after the injury and daily for five consecutive days. Functional recovery was assessed daily by an open-field test. Regardless of the polarization direction, functional scores of SCI rats that were treated with the 808-nm laser irradiation were significantly higher than those of SCI alone group (Group 1) from day 5 after injury. The locomotive function of SCI rats irradiated parallel to the spinal column (Group 3) was significantly improved from day 10 after injury, compared to SCI rats treated with the linear polarization perpendicular to the spinal column (Group 2). There were no significant differences in ATP contents in the injured tissue among the three groups. We speculate that the higher efficacy with parallel irradiation is attributable to the deeper light penetration into tissue with anisotropic scattering.

The effect of hydrogen gas on a mouse bilateral common carotid artery occlusion

In recent studies, molecular hydrogen selectively reduced the levels of hydroxyl radicals in vitro and exerted a therapeutic anti-oxidant activity in a rat middle cerebral artery occlusion model. The aim of this study was to investigate the effect of hydrogen gas on a mouse bilateral common carotid artery occlusion (BCCAO) model. Male C57BL/6J mice were subjected to transient BCCAO with a nontraumatic aneurysm clip. The mice were divided into three groups: sham, BCCAO, and BCCAO treated with 1.3 % hydrogen gas. Cerebral blood flow (CBF) in the cortex was measured sequentially for both hemispheres with a non--invasive and noncontact laser Doppler blood perfusion imager during the procedure. Vital signs were also recorded. Oxidative stress evaluated by measuring the level of 8-hydroxy-2'-deoxyguanosine (8-OHdG), neuronal injury in the hippocampal CA1 sector, and brain water content were assessed 24 h after ischemia. The hydrogen gas treatment had no significant effect on vital signs or CBF values. However, the reduction of the expression of 8-OHdG, the decrease in the neuronal injury in the hippocampal CA1 sector, and the attenuation in brain water content were observed in hydrogen-treated mice. In conclusion, hydrogen gas might be effective in a mouse BCCAO model.

Decompressive craniectomy with hematoma evacuation for large hemispheric hypertensive intracerebral hemorrhage

Hemispheric hypertensive intracerebral hemorrhage (ICH) has a high mortality rate. Decompressive craniectomy (DC) has generally been used for the treatment of severe traumatic brain injury, aneurysmal subarachnoid hemorrhage, and hemispheric cerebral infarction. However, the effect of DC on hemispheric hypertensive ICH is not well understood. To investigate the effects of DC for treating hemispheric hypertensive ICH, we retrospectively reviewed the clinical and radiological findings of 21 patients who underwent DC for hemispheric hypertensive ICH. Eleven of the patients were male and 10 were female, with an age range of 22-75 years (mean, 56.6 years). Their preoperative Glasgow Coma Scale scores ranged from 3 to 13 (mean, 6.9). The hematoma volumes ranged from 33.4 to 98.1 mL (mean, 74.2 mL), and the hematoma locations were the basal ganglia in 10 patients and the subcortex in 11 patients. Intraventricular extensions were observed in 11 patients. With regard to the complications after DC, postoperative hydrocephalus developed in ten patients, and meningitis was observed in three patients. Six patients had favorable outcomes and 15 had poor outcomes. The mortality rate was 10 %. A statistical analysis showed that the GCS score at admission was significantly higher in the favorable outcome group than that in the poor outcome group (P = 0.029). Our results suggest that DC with hematoma evacuation might be a useful surgical procedure for selected patients with large hemispheric hypertensive ICH.

Adiponectin and traumatic brain injury

Adiponectin, a circulating adipose-derived hormone regulating inflammation and energy metabolism, has beneficial actions on cardiovascular disorders. Recent studies have suggested that adiponectin might be a potential molecular target for ischemic stroke therapy; however, little is known about the effects of adiponectin on traumatic brain injury. The present study examined the immunoactivity of adiponectin.Adult male Sprague-Dawley rats were subjected to lateral fluid percussion injury using the Dragonfly device. Immuno-histochemical studies showed that the adiponectin expression was increased in the cerebral cortex at 24 h after injury and in the hippocampus at 72 h after injury. Our findings suggest that adiponectin might participate in the pathophysiological process occurring after traumatic brain injury.

A suitable formula for estimating the volume gained by decompressive craniectomy in malignant hemispheric infarction

Decompressive craniectomy (DC) improves the survivability and functional outcome in patients with malignant hemispheric infarction (MHI). The decompressive effect of DC depends on the decompressive volume (DV). The value of the formulas for estimating DV has not been reported to date. We have investigated the value of the formulas to estimate DV in patients with MHI. We analyzed the head CTs of six patients who underwent DC for MHI. We examined 1/2ABC, 1/3ABC, π/6ABC, and 2/3Sh formulas to determine the formula that gives the closest estimation of DV compared with computer-assisted volumetric analysis (gold standard). The mean volume values of the gold standard, 1/2ABC, 1/3ABC, π/6ABC, and 2/3Sh formulas were 100.2, 102.4, 68.3, 105.2, and 109.2 mL respectively. Spearman's correlation coefficient was assessed for DV obtained by each of the four different formulas relative to the gold standard. These were as follows: 1/2ABC = 0.8095 (p < 0.05), 1/3ABC = 0.8095 (p < 0.05), π/6ABC = 0.7381 (p < 0.05), and 2/3Sh = 0.4524 (p > 0.05). In conclusion, the 1/2ABC formula is the most useful and the closest estimation of DV in patients with MHI after DC.

Increased xCT expression correlates with tumor invasion and outcome in patients with glioblastomas

BACKGROUND

xCT is a light chain of the cystine/glutamate antiporter system xc. Glutamate that is released by system xc plays an important role in the infiltration of glioblastoma (GBM) cells. Furthermore, increased glutathione synthesis by system xc may protect tumor cells against oxidative stress induced by radiotherapy and chemotherapy.

OBJECTIVE

To investigate whether the levels of xCT expression correlated with infiltrative imaging phenotypes on magnetic resonance imaging and outcomes in patients with GBMs.

METHODS

Forty patients with histologically confirmed primary GBMs were included in the study. Patient charts were retrospectively reviewed for age, sex, Karnofsky Performance Status Scale score, Mini-Mental State Examination score, magnetic resonance imaging features, xCT expression, isocitrate dehydrogenase 1 R132H expression, O-methylguanine-DNA methyltransferase promoter methylation status, type of surgery, progression-free survival, and overall survival.

RESULTS

In invasive margins, xCT expression was weak in 20 patients and strong in 20 patients. A Cox regression model revealed that a Karnofsky Performance Status Scale score less than 60 (hazard ratio [HR]: 4.525; P = .01), partial removal (HR: 2.839; P = .03), and strong xCT expression (HR: 4.134; P < .001) were significantly associated with shorter progression-free survival and that partial removal (HR: 2.865; P = .03), weak isocitrate dehydrogenase 1 R132H expression (HR: 15.729; P = .01), and strong xCT expression (HR: 2.863; P = .04) were significantly associated with shorter overall survival.

CONCLUSION

These findings suggest that xCT is an independent predictive factor in GBMs.

Safety of intravenous administration of hydrogen-enriched fluid in patients with acute cerebral ischemia: initial clinical studies

BACKGROUND

Most of the results regarding hydrogen (H2) therapy for acute cerebral ischemia are derived from in vitro studies and animal experiments, with only a few obtained from human trials with a limited number of subjects. Thus, there is a paucity of information regarding both the beneficial therapeutic effects as well as the side effects of H2 on acute cerebral ischemia in humans. We designed a pilot study to investigate single dose intravenous H2-administration in combination with edaravone, aiming to provide an initial estimate of the possible risks and benefits in select patients presenting with acute ischemic stroke.

METHODS

An open-label, prospective, non-randomized study of intravenous H2-administration was performed in 38 patients hospitalized for acute ischemic stroke. All patients received an H2-enriched intravenous solution in addition to edaravone immediately after the diagnosis of acute ischemic stroke. Acute stroke patients within 3 h of onset received intravenous tissue plasminogen activator (t-PA) (0.6 mg/kg) treatment, and patients receiving t-PA had to commence the administration of the H2-enriched intravenous solution and edaravone before or at the same time as the t-PA was infused.

RESULTS

Complications were observed in 2 patients (5.3%), which consisted of diarrhea in 1 patient (2.6%) and cardiac failure in 1 patient (2.6%). No deterioration in laboratory tests, urinary tests, ECG, or chest X-ray radiograms occurred in any patient in this study. In all patients, the mean National Institutes of Health Stroke Scale (NIHSS) scores at baseline, and 7, 30, and 90 d after admission were 8.2 ± 7.5, 5.6 ± 7.1, 4.9 ± 6.5, and 4.5 ± 6.3, respectively. The early recanalization was identified in 4 of 11 patients (36.4%) who received intravenous t-PA administration. Hemorrhagic transformation was observed in 2 patients (18.2%). None of the patients in this study that were treated with t-PA developed symptomatic intracranial hemorrhage.

CONCLUSIONS

Data from the current study indicate that an H2-enriched intravenous solution is safe for patients with acute cerebral infarction, including patients treated with t-PA.

Effects of a head-down tilt on cerebral blood flow in mice during bilateral common carotid artery occlusion

Objectives:

Data on the optimal head position for patients with acute ischemic stroke are unavailable. We evaluated the effects of mild head-down tilt (HDT) on cerebral blood flow (CBF) in mice during bilateral common carotid artery occlusion (BCCAO).

Materials and Methods:

We used mice with BCCAO (35 minutes) and divided these into 2 groups ( n=16): BCCAO at 0°-HDT and 5°-HDT. CBF was measured for both hemispheres with a non-invasive laser Doppler blood perfusion imager. Changes in CBF during BCCAO were examined in both groups.

Results:

A significantly greater increase in CBF in both hemispheres was observed in 5°-HDT mice than in 0°-HDT mice (126.1% (8.715)% vs. 102.1% (4.718)%; P=0.0294).

Conclusion:

HDT enhanced the increase in CBF in both hemispheres in the mouse BCCAO model. The potential mechanism underlying CBF increase enhanced by HDT during BCCAO warrants further investigation.

Traumatic hematoma of the posterior fossa

Posterior fossa injury is rare, occurring in less than 3 % of head injuries. We retrospectively reviewed patients' clinical and radiological findings, management, and outcomes. The aim of the present study was to investigate the features of posterior fossa hematoma, including posterior fossa epidural hematoma (EDH), posterior fossa subdural hematoma (SDH), and intracerebellar hematoma. From January 1995 to January 2009, 4,315 patients with head trauma were hospitalized at our institution. The -present study focused on 41 patients (1.0 %) with traumatic hematomas of the posterior fossa. Eighteen patients had EDH, 10 patients had SDH, and 17 patients had intracerebellar hematomas. In each type of injury, occipital bone fractures were seen in many patients, and hematoma enlargement was often observed within a few days of the injury. In addition, a high frequency of associated lesions and a high poor outcome rate were features of intracerebellar hematomas and -posterior fossa SDH. The present study suggests that repeat CT imaging and careful management are necessary until the lesion is stabilized, and patients showing lesions with mass effects should therefore be immediately treated with surgery.

Surgical results after primary decompressive craniectomy in poor-grade aneurysmal subarachnoid hemorrhage

It is well known that patients with poor-grade aneurysmal subarachnoid hemorrhage (SAH) have poor outcomes owing to significant mass effect and brain stem compression. On the other hand, decompressive craniectomy (DC) has shown efficacy in reducing morbidity and mortality in patients with intracranial hypertension. Here, we study the efficacy of DC in poor-grade SAH with attention to surgical outcome. A total of 38 consecutive patients with poor-grade SAH was treated in our hospital between 1 August 2005 and 30 July 2010. Among these 38 patients, we involved 15 patients with DC in the present study. We retrospectively reviewed medical charts and radiological findings. Glasgow Outcome Scale score on discharge showed good response in 1 (6.7 %), moderate disability in 6 (40.0 %), severe disability in 4 (28.1 %), vegetative state in 2 (1.3 %), and death in 2 (13.3 %). In particular, 3 grade IV patients (50.0 %) had a favorable outcome. Recent several experimental studies also indicated that DC significantly improves outcome owing to increased perfusion pressure or reduced intracranial pressure. We suggest that the DC provided the efficacy in reducing mortality in poor-grade SAH patients.

Evaluation of the stage of hemorrhage using optical diffuse reflectance spectroscopy: an in vivo study

Intracerebral hemorrhage (ICH) is a common and often fatal subtype of stroke. Estimation of the stage of hemorrhage allows clinicians to know when the hemorrhage occurred, even in unconscious patients, enabling decisions to be made about the optimal management and treatment strategy. After ICH, oxidative denaturation of the hemoglobin progresses, and deoxyhemoglobin is gradually converted to methemoglobin. MRI has been used to estimate the stage of hemorrhage by evaluating the status of hemoglobin. However, there is currently no bedside device that can be used for the measurement of hemoglobin derivatives in patients with hematomas. The aim of the present study was to investigate the validity of using optical diffuse reflectance spectroscopy (ODRS) for bedside evaluation of the stage of hemorrhage. An ICH model was generated in adult Sprague-Dawley male rats by stereotactically injecting 50 μl of autologous blood into the right caudate nucleus. To analyze the hemoglobin derivatives in the hematomas, ODRS measurement was performed for the rats in vivo. In all rats, we found increased absorption at around 630 nm, which indicated the formation of methemoglobin. In conclusion, the results of the present study suggest that ODRS allows clinicians to more easily evaluate the stage of hemorrhage at the patient's bedside.

Diffuse light reflectance signals as potential indicators of loss of viability in brain tissue due to hypoxia: charge-coupled-device-based imaging and fiber-based measurement

Brain tissue is highly vulnerable to ischemia/hypoxia, and real-time monitoring of its viability is important. By fiber-based measurements for rat brain, we previously observed a unique triphasic reflectance change (TRC) after a certain period of time after hypoxia. After TRC, rats could not be rescued, suggesting that TRC can be used as an indicator of loss of brain tissue viability. In this study, we investigated this diffuse-reflectance change due to hypoxia in three parts. First, we developed and validated a theoretical method to quantify changes in the absorption and reduced scattering coefficients involved in TRC. Second, we performed charge-coupled-device-based reflectance imaging of the rat brain during hypoxia followed by reoxygenation to examine spatiotemporal characteristics of the reflectance and its correlation with reversibility of brain tissue damage. Third, we made simultaneous imaging and fiber-based measurement of the reflectance for the rat to compare signals obtained by these two modalities. We observed a nontriphasic reflectance change by the imaging, and it was associated with brain tissue viability. We found that TRC measured by the fibers preceded the reflectance-signal change captured by the imaging. This time difference is attributable to the different observation depths in the brain with these two methods.

Photomechanical wave-driven delivery of siRNAs targeting intermediate filament proteins promotes functional recovery after spinal cord injury in rats

The formation of glial scars after spinal cord injury (SCI) is one of the factors inhibiting axonal regeneration. Glial scars are mainly composed of reactive astrocytes overexpressing intermediate filament (IF) proteins such as glial fibrillary acidic protein (GFAP) and vimentin. In the current study, we delivered small interfering RNAs (siRNAs) targeting these IF proteins to SCI model rats using photomechanical waves (PMWs), and examined the restoration of motor function in the rats. PMWs are generated by irradiating a light-absorbing material with 532-nm nanosecond laser pulses from a Q-switched Nd:YAG laser. PMWs can site-selectively increase the permeability of the cell membrane for molecular delivery. Rat spinal cord was injured using a weight-drop device and the siRNA(s) solutions were intrathecally injected into the vicinity of the exposed SCI, to which PMWs were applied. We first confirmed the substantial uptake of fluorescence-labeled siRNA by deep glial cells; then we delivered siRNAs targeting GFAP and vimentin into the lesion. The treatment led to a significant improvement in locomotive function from five days post-injury in rats that underwent PMW-mediated siRNA delivery. This was attributable to the moderate silencing of the IF proteins and the subsequent decrease in the cavity area in the injured spinal tissue.

Traumatic peritentorial subdural hematomas: a study of 32 cases

AIM

This study aimed to investigate the clinicoradiological features in patients with traumatic peritentorial subdural hematomas (SDHs).

MATERIAL AND METHODS

We retrospectively reviewed the clinical and radiological findings, management criteria, and outcomes in 32 patients with peritentorial SDHs. The outcomes were classified as favorable (good recovery or moderate disability) or poor (severe disability, vegetative state, or death).

RESULTS

Of the 32 patients, 19 were male and 13 were female. The patients' ages ranged from 10-92 years (mean age, 60.9 years). Coagulopathies were observed in 23 patients. Twenty-four patients presented with associated intracranial lesions. Eighteen patients had favorable outcomes and 14 had poor outcomes. All patients were treated conservatively. The presence of coagulopathy (p = 0.024) and presence of convexity SDH (p = 0.008) correlated with the outcome.

CONCLUSION

The patients with traumatic peritentorial SDHs were predominantly male and relatively elderly, and had a high incidence of coagulopathy, associated intracranial lesions (especially falx SDHs), a high rate of impact in the occipital or frontal regions, and a low incidence of skull fractures. The factors that were correlated with outcome in patients receiving conservative therapy were the presence of coagulopathy and the presence of convexity SDH.

Anaplastic hemangiopericytoma manifesting as a rapidly enlarging extracranial mass lesion

We, herein, present a patient with a recurrent anaplastic hemanigiopericytoma manifesting as a rapidly enlarging extracranial mass lesion, which was revealed by pathological and intraoperative findings. In practice, this case highlights the mandatory need for a careful long-term follow-up for patients with hemangiopericytoma, since recurrence with a greater degree of malignancy can develop following an extended disease-free interval, as such knowledge will be helpful for planning the optimal surgical procedures.

Vestibular schwannoma with repeated intratumoral hemorrhage

Repeated hemorrhage from a vestibular schwannoma is very rare. We report a 15-year-old male, to our knowledge the fourth known patient with repeated hemorrhage of vestibular schwannoma, who presented with rapidly progressive right-sided hearing loss and tinnitus. MRI showed a mass lesion in the right cerebellopontine angle. T1-weighted and T2-weighted MRI revealed a hyperintense intratumoral area, indicating subacute hemorrhage within the tumor. Nine weeks after the initial onset, the patient again presented with a sudden onset headache, nausea, and ataxia. A CT scan showed recurrence of an intratumoral hemorrhage. A subtotal resection was achieved. A histopathological examination of the resected specimen showed typical features of schwannoma. We review the pertinent literature and discuss the features of repeated hemorrhage from a vestibular schwannoma.

Hydrogen may inhibit collagen-induced platelet aggregation: an ex vivo and in vivo study

OBJECTIVE

Hydrogen selectively reduces hydroxyl radicals and peroxynitrite, and numerous experimental and clinical studies suggest that hydrogen can exert potent cellular protective effects against a wide variety of diseases. Furthermore, there is increasing evidence that antioxidants can modulate platelet activation. The aim of the present study was to investigate the relationship between hydrogen and collagen-induced platelet aggregation.

METHODS

For human ex vivo studies, we collected blood samples from six healthy humans and added normal saline or hydrogen-rich saline to blood and platelet-rich plasma. We found that collagen (1 µg/mL)-induced platelet aggregation was significantly inhibited by hydrogen-rich saline compared with a normal saline group (p=0.044). For rat in vivo studies, animals (n=17) were exposed to either nitrogen-based mixed gas with hydrogen (H2 gas group; n=9) or without hydrogen (non-H2 gas group; n=8). Additionally, another animals (n=13) administered either normal (NS group; n=7) or hydrogen-rich saline (HS group; n=6) (5 ml/kg) via intravenous infusion. Blood samples were drawn from the vena cava before treatment and from the right ventricle after treatment. Collagen (12 µg/mL)-induced platelet aggregation was then measured.

RESULTS

Collagen-induced platelet aggregation was significantly decreased in H2 gas and HS group rats (p=0.042, 0.018, respectively), while there was no difference in non-H2 gas and NS group rats before and after treatment.

CONCLUSION

In summary, these data suggest that hydrogen may inhibit collagen-induced platelet aggregation.