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). It is unclear, however, 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. Because LISWs are unaccompanied by a dynamic pressure in principle, the effects of acceleration can be excluded, allowing analysis of the pure primary mechanism (the effects of a shock wave). For all rat groups, real-time monitoring of the brain and systemic responses were conducted for up to 1 h post-exposure and motor function assessments for up to seven days post-exposure. As reported previously, brain exposure alone caused cortical spreading depolarization (CSD), followed by long-lasting hypoxemia and 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, features of 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 exposure groups, but their time courses differed depending on the groups. Rats with brain exposure alone exhibited the most evident motor dysfunction at one day post-exposure, and after that, it did not change much for up to seven days post-exposure. Alternatively, two groups of rats with lung exposure (Group 2 and Group 3) exhibited continuously aggravated motor functions for up to seven days post-exposure, 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 vagovagal reflex. Overall, the results of this study indicate the importance of the torso guard to protect the brain and its function.

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.

Feasibility of the combination of 3D CTA and 2D CT imaging guidance for clipping microsurgery of anterior communicating artery aneurysm.

OBJECTIVE: We report the technique of three-dimensional computed tomography angiography (3D CTA)+two-dimensional computed tomographic (2D CT) imaging as an adjunct in early surgery for a ruptured anterior communicating artery (ACoA) aneurysm by adopting an anterior interhemispheric approach. These combined imaging modalities provide accurate intraoperative anatomical information. METHODS: To produce images for an anterior interhemispheric approach, 3D CTA+2D coronal CT images, which are perpendicular to the direction of the surgical approach at three levels (brain surface, genu of the corpus callosum and aneurysm neck), were constructed. We also produced two 3D CTA+2D CT images of the lamina terminalis, with a horizontal 10-degree difference, to clarify the vascular architecture around the aneurysm stereotactically, as well as the dissection point and direction to open the lamina terminalis. Furthermore, we produced a 3D CTA+2D sagittal CT image at the midline, which allowed us to understand the anatomical architecture of the aneurysm, planum sphenoidale and tuberculum sellae. In addition, four different 3D CTA aneurysm images were produced for deciding the clip size preoperatively. RESULTS: The imaging findings in 28 patients with 28 ACoA aneurysms facilitated early clipping. Based on these 3D CTA+2D CT images, we conducted aneurysm surgery, and successfully performed neck clipping via an anterior interhemispheric approach. CONCLUSION: The combination of 3D CTA and 2D CT images is a feasible and useful method of image guidance for ACoA aneurysm microsurgery.

Highly site-selective transvascular drug delivery by the use of nanosecond pulsed laser-induced photomechanical waves.

Photomechanical waves (PMWs), which were generated by irradiation of a light-absorbing material (laser target) with nanosecond laser pulses, were used for targeted transvascular drug delivery in rats. An Evans blue (EB) solution was injected into the tail vein, and laser targets were placed on the skin, muscle and brain. Each laser target was irradiated with a laser pulse(s) and 4h later, the rat was perfused and the distribution of EB fluorescence in the targeted tissues was examined. We observed laser fluence-dependent and hence PMW pressure-dependent extravasation of EB selectively in the tissues that had been exposed to a PMW(s). Uptake of leaked EB into cells in extravascular space was also observed in the targeted tissues. Tissue damage or hemorrhage was not apparent except in the brain exposed to the highest laser fluence used. The results for the brain indicated opening of the blood-brain barrier (BBB). Reverse-order (PMW application before EB injection) experiments showed that the BBB was closed in the duration from 8h to 12h after PMW application at a laser fluence of 0.5J/cm(2). Since EB molecules are strongly bound with serum albumin in blood, the results indicate that the present method can be applied not only to small molecules but also to macromolecules.

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.

Sulfasalazine and temozolomide with radiation therapy for newly diagnosed glioblastoma.

BACKGROUND: A recent phase 1/2 clinical trial argued for caution for the use of sulfasalazine in progressive glioblastoma (GBM). However, the study enrolled patients with recurrent or progressive high-grade glioma indicating that patients recruited probably had severe disease. Thus, the study may not accurately reflect the effectiveness of sulfasalazine for GBM and we hypothesized that earlier sulfasalazine administration may lead to anticancer effects. AIM: The aim of this study was to investigate whether sulfasalazine can improve the outcomes of patients with newly diagnosed GBM. SUBJECTS AND METHODS: A total of 12 patients were treated with temozolomide and sulfasalazine with radiation therapy after surgery. Twelve patients with primary GBM treated with temozolomide and radiation therapy formed the control group. Progression-free survival (PFS), overall survival (OS) and seizure-free survival (SFS) curves were obtained using the Kaplan-Meier method. The survival curves were compared using the log-rank test. RESULTS: The median OS, PFS and SFS did not differ between the groups. Grade 3 or 4 adverse events occurred over the duration of the study in nine (75%) patients. The median SFS was 12 months in nine patients who received sulfasalazine administration for more than 21 days, which was strongly but not significantly longer than the 3 months observed in the control group (P = 0.078). CONCLUSIONS: Sulfasalazine treatment with temozolomide plus radiotherapy for newly diagnosed primary GBM is associated with a high rate of discontinuation due to hematologic toxic effects. This treatment may have no effect on OS or PFS, although it may improve seizure control if an adequate dose can be administered.

Acute posterior fossa epidural hematoma in a newborn infant with Menkes disease.

Epidural hematoma (EDH) in newborn infants is rare compared with other types of intracranial hemorrhages. Furthermore, posterior fossa EDH is extremely rare. We present a case of posterior fossa EDH in an infant with Menkes disease with accessory bones in the occiput. A male infant with a condition diagnosed with Menkes disease by prenatal testing was born at 39 weeks via vacuum extraction. The patient presented with a mild tremor at 2 days after delivery. A brain computed tomography (CT) scan showed an acute EDH in the posterior fossa, extending into the occipitoparietal area. Three-dimensional CT and bone window CT scan revealed several accessory bones, diastasis of 1 accessory suture, a communicated fracture, and a linear fracture in the occipital bone. Furthermore, a bone fragment from a communicated fracture displaced toward the inside. The patient was treated conservatively for EDH because of his good general condition. The hematoma gradually resolved, and his tremor did not recur. We suggest the following mechanism of posterior fossa EDH development in our patient: (1) external force was applied to the occiput inside the birth canal during delivery, resulting in diastasis; (2) a communicated fracture occurred, and a bone fragment displaced toward the inside (linear fracture was caused indirectly by the force); (3) a transverse sinus was injured by the fragment; and (4) EDH developed in both the posterior fossa and supratentorial region. Copper deficiency can also cause fragility of connective tissues, vessels, and bones.

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.

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.

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.