Yoshihiko Shiro

Reduction of ischemic brain injury by topical application of insulin-like growth factor-I after transient middle cerebral artery occlusion in rats

In order to examine the effect of insulin-like growth factor-1 (IGF-1) on ischemic brain injury, IGF-1 was applied topically on the surface of reperfused rat brain after 60 min of transient middle cerebral artery occlusion (MCAO). In contrast to the cases treated with vehicle, the infarct area was greatly reduced at 24 h of reperfusion by treatment with IGF-1. Terminal deoxynucleotidyl transferase mediated dUTP-biotin in situ nick labeling (TUNEL) staining and immunoreactivity for glycogen synthase kinase 3beta (GSK3beta) were also markedly reduced in the brains with IGF-1 treatment. The present results suggest that the treatment with IGF-1 significantly ameliorates brain injury after transient focal brain ischemia associated with the reduction of TUNEL and GSK3beta stainings.

Protective effect of ginkgo extract on rat brain with transient middle cerebral artery occlusion.

Abstract It has been empirically known that Ginkgo extract is useful for reducing many symptoms associated with cerebral blood flow (CBF) insufficiency, but its mechanisms have been uncertain. In the present study, therefore, we gave Ginkgo extract to rats with per os digestion, and investigated its effect on CBF and ischemic brain damage with middle cerebral artery occlusion (MCAO). The treatment with Ginkgo extract (W mg 100g-1 rat) increased CBF in the normal condition, but the degree of increase in CBF was lesser during and after MCAO. TTC staining showed that infarct volume was reduced with Ginkgo treatment. TUNEL and HSP72 immunostaining confirmed the protective effect of Ginkgo treatment reducing numbers ofTUNEL and FiSP72 positive cells. Immunohistochemical analysis showed that caspase-3 expression was less abundant in Ginkgo treated rats. The present results suggest that Ginkgo extract contains a substance which increases normal CBF and reduces ischemic brain damage. [Neurol Res 2000; 22: 517-521]

Induction of glial cell line-derived neurotrophic factor receptor proteins in cerebral cortex and striatum after permanent middle cerebral artery occlusion in rats.

In an attempt to elucidate whether glial cell line-derived neurotrophic factor (GDNF) receptors are induced after ischemic brain injury, possible expression of immunoreactive GDNF receptor-alpha1 (GFRalpha-1) and c-ret (RET) was examined at 3, 8, or 24 h after permanent middle cerebral artery occlusion (MCAO) in rats. Immunohistochemical study showed that both GFRalpha-1 and RET staining cells which were not detected in sham control brain, were present in the ipsilateral cortex and caudate at 3 to 8 h after permanent MCAO, and then decreased but remained to some extent at 24 h. Positive cells for both GDNF receptors were predominantly in cortical neurons of ischemic penumbral area. Western blot analysis confirmed the induction of those receptors after permanent MCAO. This rapid induction of GFRalpha-1 and RET, which correlates with the similar induction of GDNF under these conditions, may play a role in the early response to ischemic brain injury.

Early decrease of survival signal-related proteins in spinal motor neurons of presymptomatic transgenic mice with a mutant SOD1 gene

The mechanisms of motor neuronal death in amyotrophic lateral sclerosis (ALS) remain to be unclear. Phosphatidy-linositol 3-kinase (PI3-K) and its main downstream effector, Akt/protein kinase B (PKB) have been shown to play a central role in neuronal survival against apoptosis supported by neurotrophic factors. In order to investigate a possible impairment of survival signaling, we examined expressions of PI3-K and Akt in the spinal cord of the transgenic mice overexpressing a mutant Cu/Zn superoxide dismutase (SOD1) gene, a valuable model for human ALS. Immunoblotting and immunohistochemical analyses showed that the majority of spinal motor neurons lost the immunoreactivities for both PI3-K and Akt in the early and presymptomatic stage that preceded significant loss of the neurons. The present results suggest that an early decrease of survival signal proteins in the spinal motor neurons may account for the subsequent motor neuronal loss in this animal model of ALS.

Sjögren’s syndrome with acute transverse myelopathy as the initial manifestation

This is the first report of a patient with acute transverse myelopathy as the initial manifestation of primary Sjögrens syndrome (SS). The patient developed tetraparesis and sensory disturbance within 6 days of onset. Spinal MRI showed an extensive intraparenchymal lesion with high T2-weighted signal intensity, gadolinium enhancement, and cord swelling. Although the patient did not show clinical sicca symptoms, primary SS was diagnosed on the basis of clinical tests on lacrimal and salivary glands which showed high levels of autoantibodies. Treatment with prednisone improved motor and sensory symptoms and resulted in improvement of MRI findings. The present case suggests that acute transverse myelopathy can occur as an initial symptom of SS.

Topical application of neurotrophin-3 attenuates ischemic brain injury after transient middle cerebral artery occlusion in rats

In order to examine the effect of neurotrophin-3 (NT-3) on ischemic brain injury, NT-3 was topically applied to brain surface just after 90 min of middle cerebral artery occlusion (MCAO) in rats. NT-3 significantly reduced the infarct size at 24 h of reperfusion. Terminal deoxynucleotidyl transferase-mediated dUTP-biotin in situ nick labeling (TUNEL) staining and immunohistochemical study for caspase-3 and heat shock protein 72 (HSP72) showed that NT-3 treatment decreased the number of cells with DNA fragmentation and caspase-3 and HSP72 expressions. These data suggest that NT-3 protects neuronal cells from ischemic injury, and it is possibly associated with inhibition of DNA fragmentation.

Fractal dimension analysis of static stabilometry in Parkinson's disease and spinocerebellar ataxia.

Abstract The static stabilometry patterns associated with Parkinson’s disease (PD, n = 15) and spinocerebellar ataxia (SCA, n = 15) were compared with those of normal control (n = 15) by measuring the fractal dimensions. Fractal dimensions were estimated using the modified pixel dilation (mPD) method. The fractal dimensions with closed eyes showed a significant correlation with Environmental area for SCA group (p<0.05). The fractal dimension for SCA group was significantly higher with closed eyes than that with open eyes (p<0.05). The fractal dimension with closed eyes was significantly higher in PD and SCA groups than that in normal group (p<0.05). The fractal dimension with closed eyes was higher when the clinical stage was more severe with PD and SCA group while Environmental and Longitude/Environmental areas were not. These findings suggest that the fractal dimension is more sensitive than traditional stabilometric analysis in an evaluation of postural instability in PD and SCA.

Cognitive and affective impairments of a novel SCA/MND crossroad mutation Asidan

Background:  A variety of hereditary spinocerebellar ataxia (SCA) develops a broad spectrum of both ataxia and non‐ataxia symptoms. Cognitive and affective changes are one such non‐ataxia symptoms, but have been described only in hereditary SCAs with exonic CAG gene expansion.

Tardive decrease of astrocytic glutamate transporter protein in transgenic mice with ALS-linked mutant SOD1

Abstract The expressions of glutamate transporter proteins were immunocytochemically examined in the spinal cord of transgenic mice harboring a Gly93 → Ala (G93A) mutant human SOD1 gene. Astroglial EAAT2 protein level was preserved in the ventral horn even after the beginning of paralysis, and finally decreased at terminal stage of the disease (35 weeks of age), when neuronal EAAT3 protein level was also decreased. In contrast, glial fibrillary acidic protein (GFAP) immunoreactivity progressively increased from 25 weeks of age in the ventral horn. The present results show interesting dissociative expressions of astroglial proteins EAAT2 and GFAP in the same ventral horn, but suggest not an early and primary role of EAAT2 in the motoneuronal death of this model. [Neurol Res 2002; 24: 577-581]

ENHANCED FOS EXPRESSION IN RAT LUMBAR SPINAL CORD CULTURED WITH CEREBROSPINAL FLUID FROM PATIENTS WITH AMYOTROPHIC LATERAL SCLEROSIS

The etiology of amyotrophic lateral sclerosis (ALS) remains unknown although an existence of neurotoxic substances in cerebrospinal fluid (CSF) from ALS patients have been postulated. In order to investigate a possible effect of CSF from ALS patients on cellular signaling in spinal neurons, we compared Fos-like immunoreactivity (Fos-LI) in organotypic cultures of rat lumbar spinal cord after addition of CSF from ALS patients or another neurologic disease. Fos-LI was normally present predominantly in dorsal horn neurons, whereas only a few ventral horn neurons were positive for Fos-LI. The number of Fos-LI positive neurons significantly increased in dorsal horn with addition of CSF from ALS patients as well as glutamate at 100 microM. However, the increase was not observed with addition of CSF from other neurologic diseases. The increase in Fos-LI positive neurons in dorsal horn was reversed by a further supplement of MK801, an N-methyl-D-aspartate (NMDA) receptor antagonist, but not of CNQX, an alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA)/kainate antagonist. These results indicate that there may be substances in CSF from ALS patients that stimulate Fos expression in certain populations of spinal neurons via the NMDA receptors.