Experimental models of spinal open neural tube defect and Chiari type II malformation.

INTRODUCTION: Experimental animal models are essential for investigation of the pathoembryogenesis, pathophysiology, and management strategy of spinal open neural tube defect (ONTD) and its associated anomalies including Chiari type II malformation. Genetic, chemical/nutrient, and surgical models have been widely used for a variety of purposes. The aim of this article is to review the representative animal models of spinal ONTD and associated Chiari type II malformation with respect to their advantages and disadvantages. DISCUSSION: Among them, the surgical model was described in detail because it is familiar to neurosurgeons and it is used for evaluations of prenatal repair of spinal ONTDs. The surgical model also has advantages because it allows quantitative analysis of the lesions. A description of our previous studies on spinal ONTDs using a chick surgical model is presented as an example.

Subacute course of common iliac arterial laceration in lumbar disc surgery.

Vascular injuries in lumbar disc surgery are serious complications which may be overlooked due to a broad range of clinical manifestations. It is important to be aware of the perioperative implications of this rare occurrence to lower mortality risk. A 20-yr-old man with a right L4-5 lumbar disc protrusion was operated on routinely under a surgical microscope. A bloody surgical field was noted temporarily during a discectomy along with a decreased blood pressure. After fluid resuscitation with an ephedrine injection, the bleeding soon stopped spontaneously and his vital signs were stabilized. Fifty hours after the operation, the patient showed signs of hypovolemic hypotension with abdominal distension. The right femoral artery pulsation was absent on palpation. An enhanced CT angiography revealed a retroperitoneal hematoma and obstruction of the left common iliac artery. An urgent laparotomy was done to repair the injured vessel by excision and interposition of a graft. The patient had an uneventful recovery.The subacute course of deterioration might have been due to intermittent blood leakage from the lacerated common iliac artery, which was sealed spontaneously. It is very important to pay close attention to post-surgical clinical manifestations to avoid a potentially fatal outcome in lumbar disc surgery.

A Novel Acute Discogenic Myelopathy Model Using Merocel® Sponge: Comparison With Clip Compression Model in Rats.

Objective: Animal models of spinal cord injuries (SCIs) use rats to simulate human SCIs. Among the various techniques, clips have been used to reproduce the compression-contusion model. However, the mechanism of injury in discogenic incomplete SCI may differ from that in clip injury; however, a model has yet to be established. Previously, we issued a patent (No. 10-2053770) for a rat SCI model using Merocel®, a water-absorbing self-expanding polymer sponge. The objectives of this study were to compare the locomotor and histopathological changes between the Merocel®-compression model (MC group) and clip compression model (clip group). Methods: This study included 4 groups of rats: MC (n=30), MC-sham (n=5), clip (n=30), and clip-sham (n=5). Locomotor function was evaluated in all groups using the Basso, Beattie, and Bresnahan (BBB) scoring system, 4 weeks after injury. Histopathological analyses included morphology, presence of inflammatory cells, microglial activation, and extent of neuronal damage, which were compared among the groups. Results: The BBB scores in the MC group were significantly higher than those in the clip group throughout the 4 weeks (p<0.01). Neuropathological changes in the MC group were significantly less severe than those in the clip group. In addition, motor neurons were well preserved in the ventral horn of the MC group but poorly preserved in the ventral horn of the clip group. Conclusion: The novel MC group can help elucidate the pathophysiology of acute discogenic incomplete SCIs and may be applied in various SCI therapeutic strategies.

Erratum: A Novel Acute Discogenic Myelopathy Model Using Merocel® Sponge: Comparison With Clip Compression Model in Rats.

[This corrects the article on p. 204 in vol. 19, PMID: 37431382.].

Chiari Malformation with Surgically Induced Open Neural Tube Defect in Late Chick Embryos : Characterization by Magnetic Resonance Imaging and Histopathological Analysis.

OBJECTIVE: Chiari II malformation (CM II) is still the main cause of severe morbidity and mortality in children with open neural tube defects (ONTDs). The goal of this study was to validate a CM II model in late-stage chick embryos with surgically induced ONTDs. METHODS: To make the chick embryo model of ONTD, their neural tubes were opened for a length of 5-6 somites at the thoracic level in Hamburger and Hamilton stage 18 chick embryos (n=150). They were reincubated in ovo. up to a total age of 17-21 days. A total of 19 embryos survived and were assigned to either the postoperative day (POD) 14-15 group (n=6) or the POD 17-18 group (n=13). Magnetic resonance imaging (MRI) and histopathologic findings of embryo heads with spinal ONTDs were compared with age-matched normal chick embryos. RESULTS: The chick embryos with ONTDs demonstrated definite and constant structural changes, such as downward displacement of the cerebellum to just above the foramen magnum and narrow and small cerebrospinal fluid spaces in the crowded small posterior fossa. These morphologic features were more prominent in the POD 17-18 group than in the POD 14-15 group. CONCLUSION: This is the first description of CM II with spinal ONTD in a late-stage chick embryo model with MRI and histopathological analysis. The morphological changes of the posterior fossa in this study mimic those of CM II associated with spinal ONTD in humans. This model will facilitate investigation of the pathogenesis of CM II.

Ruptured Fusiform Anterior Cerebral Artery Aneurysm in an Infant : Case Report and a Literature Review.

Ruptured intracranial aneurysms in infants are rare and infantile fusiform anterior cerebral artery (ACA) aneurysms are much rarer. In this report, we described the case of a 7-month-old infant with a ruptured fusiform ACA aneurysm who presented with seizure and underwent endovascular treatment. The patient was initially in a coma and the neurologic condition did not improve after treatment. The clinical characteristics of the case and literature review were discussed.

Imaging of the walls of saccular cerebral aneurysms with double inversion recovery black-blood sequence.

In this study, we evaluated the wall of saccular cerebral aneurysms (SCAs) using two-dimensional double inversion recovery black-blood sequence (BBDI). We examined 14 patients with an unruptured SCA (USCA). The BBDI was peripheral-pulse gated, and was acquired during the mid-diastolic period. We evaluated whether the aneurysmal wall could be visualized with BBDI, and the wall thickness in the neck and dome portion of the aneurysm was measured in cases with acceptable imaging quality. BBDI demonstrated the USCA walls in ten patients. In four patients, the USCA walls were poorly delineated from the adjacent brain parenchyma or cerebrospinal fluid. The mean aneurysm size was 8.0 mm. The mean thickness of the aneurysmal wall in the neck portion was 0.60 +/- 0.13 mm in 10 cases. The mean thickness at the dome portion was 0.46 +/- 0.05 mm in five cases. In this study, BBDI revealed some portion of the USCA wall, despite the limited spatial and contrast resolution for delineation of the entire USCA wall. In our opinion, this technique may be used as an additional imaging tool for the evaluation of the aneurysmal wall.

The expression of transferrin binding protein in the turtle nervous system.

Transferrin binding protein (TfBP) is a cytoplasmic glycoprotein that was originally isolated from the chick oviduct. As we previously demonstrated the constitutive expression of TfBP in the avian nervous system, in this study we examined whether TfBP is expressed in the reptilian nervous system. In accordance with previous findings in the chicken, oligodendrocytes were most prominently labeled by antiserum to TfBP. Great variability was observed between different regions of the central nervous system (CNS) in terms of TfBP-labeled oligodendrocyte numbers. In the retina, TfBP was localized specifically in the cells that are morphologically oligodendrocytes and present in the optic nerve and the ganglion cell layer. TfBP staining was also seen in the Schwann cells of peripheral nerves. Furthermore, choroid plexus cells and capillary endothelial cells similarly exhibited strong reactions. These results may reflect the fact that the homology of nervous system genes is conserved between close phylogenetic lines, and proove the potential of TfBP as a marker for oligodendrocytes in avian as well as reptile.

Cerebellar pilocytic astrocytoma presenting with intratumor bleeding, subarachnoid hemorrhage, and subdural hematoma.

INTRODUCTION: Massive intracranial hemorrhage is a very rare initial presentation of cerebellar pilocytic astrocytomas. There are no reports in the medical literature on a cerebellar pilocytic astrocytoma presenting with intratumor bleeding (ITB), subarachnoid hemorrhage (SAH), and subdural hematoma (SDH). CASE REPORT: A 15-month-old boy presented with lethargy and nausea to our hospital. Magnetic resonance imaging showed a mass with ITB at the left cerebellar hemisphere in addition to SDH in the posterior fossa and SAH at the interpeduncular cistern. The patient underwent emergency surgery. On incising the dura, we found SDH, the tumor was visible at the cerebellar cortex, and near total removal followed. Microscopic examination of tissue sections revealed a pilocytic astrocytoma. DISCUSSION: The authors' case is the first report with a presentation including ITB, SAH, and SDH. The presumed mechanism of the SAH and SDH was leaking of the ITB into subarachnoid and subdural spaces.

Immunohistochemical study of cathepsin D in the spinal cords of rats with clip compression injury.

This study examined the temporal expression of cathepsin D protein and its cellular localization in the spinal cords of rats after a clip compression injury to determine the involvement of cathepsin D in spinal cord injury (SCI). Western blot analysis showed a significant increase in the approximately 31-kDa active form of cathepsin D on days 4 and 7 after the SCI, while the level of the approximately 44-kDa inactive form remained relatively unchanged. Immunohistochemistry revealed cathepsin D with constitutive localization in most neurons and some gliocytes in the normal spinal cord to be intensely immuno-detected primarily in CD68-positive activated macrophages/microglia in the SCI lesions. Overall, these findings suggest that cathepsin D plays an important role in the phagocytosis and lysosomal activation of macrophages/microglia during the central nervous system inflammation caused by trauma.

Morphological study of sinus flow in the confluence of sinuses.

The confluence of sinuses (CS; torcular herophili) is represented by the junction of the superior sagittal (SSS), straight (SS), occipital (OS), and two transverse sinuses (TS). The objective of this study was to interpret sinus flow around the CS by morphological investigation of the sinuses. This study is based on visual examination of dural venous sinuses in the region of the CS in 31 adult cadavers. In the inflow zone, we examined the direction of SSS and SS flow. In the communication zone, we examined the extent to which outflow sinuses communicate with other sinuses. In the outflow zone, we used the diameters of outflow sinuses to determine anatomical dominance. The SSS entered the CS via the right TS in 16 cases (51.6%) and via the center of the CS in 14 cases (45.2%). The SS entered via the center of the CS in 18 cases (58.1%) and via the left TS in 11 cases (35.5%). Outflow sinuses communicated freely in 26 cases (83.8%) and communicated partially in five cases (16.2%). Partial communication was the result of a septate CS. In terms of outflow, the right TS was dominant in 11 cases (35.5%), and in 18 cases (58.1%), outflow was symmetrical. The direction of SSS inflow was different from that of SS inflow, and partial communication was observed in five cases (16.1%). Therefore, the presence of a septum may be considered an anatomical factor, with implications in diagnosis or in the sacrifice of the outflow sinus of the CS.

Development and Growth of the Normal Cranial Vault : An Embryologic Review.

Understanding the development of a skull deformity requires an understanding of the normal morphogenesis of the cranium. Craniosynostosis is the premature, pathologic ossification of one or more cranial sutures leading to skull deformities. A review of the English medical literature using textbooks and standard search engines was performed to gather information about the prenatal development and growth of the cranial vault of the neurocranium. A process of morphogenic sequencing begins during prenatal development and growth, continues postnatally, and contributes to the basis for the differential manner of growth of cranial vault bones. This improved knowledge might facilitate comprehension of the pathophysiology of craniosynostosis.

Temporal expression of osteopontin and CD44 in rat brains with experimental cryolesions.

Expression of osteopontin and CD44 in the brain was studied after cryolesioning to understand how osteopontin and its receptor, CD44, are involved in processes in the brains of rats with cryolesions. Western blot analysis showed that osteopontin increased significantly at days 4 and 7 post-injury and declined slightly thereafter in cryolesioned brains in comparison with levels in sham-operated controls. An immunohistochemical study localized osteopontin in activated microglia/macrophages in the core lesions, where the majority of macrophages proliferate. Osteopontin was also detected temporarily in some neurons and a few astrocytes in the lesion periphery on days 4 and 7 post-injury, but the immunoreactivity in macrophages, neurons, and astrocytes disappeared by day 14 post-injury. There was some CD44, a receptor for osteopontin, in the brain cells of sham-operated rats. After injury, intense CD44 immunostaining was seen in the majority of macrophages and in reactive astrocytes, but not in neurons, in the ipsilateral lesions after day 4 post-injury, and this immunoreactivity remained on day 14 post-injury. These findings suggest that activated microglia/macrophages and some neurons are major sources of osteopontin during the early stage of brain damage induced by a cryolesion and that osteopontin interacts with CD44 expressed on astrocytes and activated microglia/macrophages in the damaged cerebral cortex, possibly mediating cell migration after cryolesioning in the rat brain.

Transient activation of an adaptor protein, disabled-2, in rat spinal cord injury.

We previously reported that disabled-2 (Dab-2), a cytosolic adaptor protein, was expressed in inflammatory and glial cells in the central nervous system (CNS) in experimental autoimmune encephalomyelitis and cerebral cryoinjury. Here, to determine the pattern of Dab-2 expression in a clip compression-induced rat spinal cord injury (SCI) model, the protein level and localization of Dab-2 in the spinal cord were investigated in rats with SCI using Western blotting and immunohistochemistry. Western blotting revealed that the expression of both the 75- and 100-kDa isoforms of Dab-2 peaked significantly in the spinal cord after clip compression injury 7 days post-injury compared to sham controls, and declined slightly thereafter. Immunohistochemistry revealed weak Dab-2 immunostaining in some neurons, glial cells, and ependymal cells in the spinal cords of the control animals, compared to staining in the macrophages and reactive astrocytes in lesions of the SCI animals. Overall, these findings suggest that both isoforms of Dab-2 are transiently upregulated in response to SCI and that the increased expression of Dab-2 is associated with the early activation of macrophages and astrogliosis in the course of CNS inflammation.

Clinical significance of cerebral microbleeds locations in CADASIL with R544C NOTCH3 mutation.

BACKGROUND AND PURPOSE: Although cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most common single-gene disorder of cerebral small blood vessels caused by NOTCH3 mutations, little has been described about the variation in the clinical findings between its underlying types of mutations. In particular, the presence of cerebral microbleeds (CMBs) has been an increasingly recognized magnetic resonance imaging finding in CADASIL, but their clinical significance is not clear. The purpose of this study is to assess whether CMBs are associated with symptomatic stroke in the CADASIL patients with R544C mutation and to compare the cerebral distribution of CMBs between CADASIL patients with and without symptomatic stroke. METHODS: This is a cohort study of patients who were diagnosed with genotype-confirmed R544C-mutation CADASIL. Primary neurologic symptoms were recorded. Symptomatic strokes were defined as transient ischemic attack, ischemic strokes and hemorrhagic strokes. CMBs were defined as focal areas of round signal loss on T2*-weighted gradient echo planar images with a diameter of less than 10 mm. The locations of CMBs were divided into lobar, basal ganglia, thalamus, brain stem and cerebellum. Multiple logistic regressions were performed to identify the epidemiologic or vascular risk factors associated with symptomatic stroke in patients with CADASIL. RESULTS: Among total of 51 subjects in this cohort, CMBs were present in 20 of 32 patients (64.5%) in the symptomatic stroke-group and in 8 of 19 patients (42.1%) in the non-stroke group (p = 0.16). CMBs were observed more frequently in the basal ganglia (p<0.001) and the cerebellum (p<0.018) in the symptomatic stoke group compared to the non-stroke group. The mean number of CMBs was significantly higher in the symptomatic stroke group (15.4±18.0 lesions per patients with CMBs) versus those without symptomatic stroke (3.3±3.0 lesions per patients with CMBs) (p = 0.003). Hypertension was an independent risk factor for symptomatic stroke in CADASIL (p = 0.014). It was independently associated with CMBs locations as basal ganglia (p = 0.016), thalamus (p = 0.010), brainstem (p = 0.044), and cerebellum (p = 0.049). However, It was not independently associated with CMBs on lobar lesion (p = 0.152). CONCLUSIONS: In this study hypertension was an independent predictor of CMBs presence in specific brain locations, as well as symptomatic stroke in the CADASIL patients. The distribution and burden of CMBs might be a clinically useful marker for the risk of symptomatic stroke. However, further prospective studies on the relationship between CMBs distribution and symptomatic stroke are required in order to support these preliminary findings.

Temporal patterns of the embryonic intermediate filaments nestin and vimentin expression in the cerebral cortex of adult rats after cryoinjury.

The expression of two embryonic intermediate filaments, nestin and vimentin, in the rat brain at days 0 (control), 1, 4, 7 and 14 post-cryoinjury was studied to elucidate their roles in brain injury. Western blot analysis showed that both nestin and vimentin expressions in the ipsilateral cerebral cortex were significantly increased at 4 and 7 days post-cryoinjury, and were decreased at day 14 after cryoinjury. Immunohistochemistry showed that there were few nestin- and vimentin-positive cells in the cerebral cortex in normal controls. On days 4 and 7 post-injury, abundant glial cells in the periphery of the lesion were immunostained for nestin and/or vimentin; only vimentin was detected in the majority of inflammatory cells in the core lesion. These findings suggest that nestin and vimentin contribute to the repair of brain injury through the migration of activated cells and the formation of a glial scar.

Upregulation of CD44 expression in the spinal cords of rats with clip compression injury.

The expression of the extracellular matrix phosphoglycoprotein CD44 after compression injury of the spinal cord was examined in rats. Western blot analysis of tissues harvested on days 0 (sham), 1, 4 and 7 post-injury showed significant increases in CD44 expression from 1 to 7 days after compression injury compared to sham-operated controls. Immunohistochemistry revealed that CD44 was constitutively expressed in some astrocytes in sham-operated controls. At days 4-7 post-injury, CD44 was intensely expressed in astrocytes in the periphery of lesions, and in myelin sheaths, vessels, and the majority of inflammatory cells including macrophages in core lesions. The finding that expression of CD44 was upregulated after spinal cord injury suggests that CD44 contributes to cell adhesion and glial cell attraction during the early stages after spinal cord injury, and may thus promote remodeling of injured spinal cords.

Upregulation of phospholipase D1 in the spinal cords of rats with clip compression injury.

This study examined phospholipase D 1 (PLD1) expression in the central nervous system following clip compression spinal cord injury (SCI) in Sprague-Dawley rats. After inducing SCI with a vascular clip, the expression of PLD1 in the affected spinal cord was analyzed by Western blot and immunohistochemistry. Western blot analysis showed that the expression of PLD1 gradually increased in the spinal cord on days 0.5, 1, 2, and 4 post injury. Immunohistochemistry showed that some cells, including neurons, astrocytes, and some inflammatory cells, were positive for PLD1 in the lesions at days 1 and 2 post injury. At day 4, the number of PLD1-positive cells in SCI lesions increased, largely matching the increases in ED1-positive macrophages and glial fibrillary acidic protein-positive astrocytes. At this time, macrophages expressed proliferating cell nuclear antigen in addition to PLD1. These results suggest that PLD1 expression is increased in injured spinal cords, and might be involved in the activation and proliferation of macrophages and astrocytes in SCI.

Sodium salicylate-induced amelioration of experimental autoimmune encephalomyelitis in Lewis rats is associated with the suppression of inducible nitric oxide synthase and cyclooxygenases.

We studied the effects of oral administration of sodium salicylate on the expression of the pro-inflammatory mediators, nitric oxide synthase (iNOS) and cyclooxygenase- (COX-) 1 and 2, in rats with experimental autoimmune encephalomyelitis (EAE). Sodium salicylate (200 mg/kg) was administered orally for 13 days after the induction of EAE by immunization with guinea pig myelin basic protein and complete Freund's adjuvant. The onset (P<0.0001) and severity (P<0.05) of EAE paralysis in salicylate-treated animals were delayed and suppressed significantly compared with vehicle-treated controls. Western blot analysis showed that expression of COX-2 and iNOS, but not COX-1, decreased significantly in the spinal cords of salicylate-treated rats compared with vehicle-treated controls (P<0.05) and this finding was paralleled by immunohistochemical observations. These results suggest that the amelioration by salicylate of paralysis in rats with EAE is mediated in part by the suppression of COX and iNOS.

Immunohistochemical study of osteopontin in the spinal cords of rats with clip compression injury.

Expression of osteopontin (OPN) was investigated in the spinal cords of rats with clip compression injury. Western blot analysis demonstrated that OPN protein increased significantly in the spinal cord during the early stages after injury. The increased expression of OPN was partially paralleled by that of proliferating cell nuclear antigen (PCNA). Immunohistochemical staining showed that OPN was expressed in proliferating activated microglia/macrophages in core lesions and in some astrocytes at the periphery of lesions. These results indicate that expression of OPN protein increases mainly in activated microglia/macrophages after spinal cord injury, suggesting that OPN is related to cell proliferation during the early stages after injury, probably leading to tissue remodeling.