Effects of acidic pH on voltage-gated ion channels in rat trigeminal mesencephalic nucleus neurons

The effects of acidic pH on several voltage-dependent ion channels, such as voltage-dependent K⁺ and Ca²⁺ channels, and hyperpolarization-gated and cyclic nucleotide-activated cation (HCN) channels, were examined using a whole-cell patch clamp technique on mechanically isolated rat mesencephalic trigeminal nucleus neurons. The application of a pH 6.5 solution had no effect on the peak amplitude of voltage-dependent K⁺ currents. A pH 6.0 solution slightly, but significantly inhibited the peak amplitude of voltage-dependent K⁺ currents. The pH 6.0 also shifted both the current-voltage and conductance-voltage relationships to the depolarization range. The application of a pH 6.5 solution scarcely affected the peak amplitude of membrane currents mediated by HCN channels, which were profoundly inhibited by the general HCN channel blocker Cs⁺ (1 mM). However, the pH 6.0 solution slightly, but significantly inhibited the peak amplitude of HCN-mediated currents. Although the pH 6.0 solution showed complex modulation of the current-voltage and conductance-voltage relationships, the midpoint voltages for the activation of HCN channels were not changed by acidic pH. On the other hand, voltage-dependent Ca²⁺ channels were significantly inhibited by an acidic pH. The application of an acidic pH solution significantly shifted the current-voltage and conductance-voltage relationships to the depolarization range. The modulation of several voltage-dependent ion channels by an acidic pH might affect the excitability of mesencephalic trigeminal nucleus neurons, and thus physiological functions mediated by the mesencephalic trigeminal nucleus could be affected in acidic pH conditions.

Vertical One-and-a-Half Syndrome Accompanying Contralateral Abduction and Incomplete Depression Palsy Due to Thalamo-Mesencephalic Infarction / 대한평형의학회지

Vertical gaze palsy is usually associated with lesions of the rostral midbrain and thalamo-mesencephalic junction. The rostral interstitial nucleus of the medial longitudinal fasciculus (riMLF), the interstitial nucleus of Cajal, and the posterior commissure located in the midbrain are the critical area in supranuclear control of vertical eye movements. We describe a case of vertical one-and-a-half syndrome accompanying contralateral abduction and incomplete depression palsy due to thalamo-mesencephalic infarction. These vertical eye movement abnormalities are presumed to be caused by damage to the ipsilateral riMLF, interstitial nucleus of Cajal, and oculomotor fascicles.

Primary Position Upbeat Nystagmus during an Acute Attack of Multiple Sclerosis

BACKGROUND AND PURPOSE: Ocular manifestation is one of the frequent signs of an acute attack in multiple sclerosis (MS), although primary position upbeat nystagmus (PPUN) is rare. The purpose of this study is to determine the incidence of PPUN in MS and to determine the lesions that are responsible for this sign. METHODS: The medical records of 120 MS patients with acute brain lesions were reviewed over a consecutive period of 9 years; of these, 6 patients were found to have PPUN. Other ocular motor abnormalities were analyzed in combination with upbeat nystagmus, video-oculographic findings, and lesions detected on brain MRI. RESULTS: Lesions in the pontine tegmentum involving the medial longitudinal fasciculus (MLF) and ventral tegmental tract (VTT) were the most common, being observed in three of the six patients with PPUN. One patient exhibited caudal medullary lesions bilaterally affecting the paramedian portion of the posterior tegmentum, and two patients exhibited multiple lesions involving the pons with the cerebral peduncle or medulla. In five patients, other ocular motor dysfunctions, such as gaze-evoked nystagmus (n=3) and internuclear ophthalmoplegia (n=1), were found in combination with upbeat nystagmus. CONCLUSIONS: PPUN is an infrequent, ocular manifestation noted during an acute attack of MS, and was observed in 5% of the present cases. Brainstem lesions in these cases primarily involved the pontine tegmentum and the caudal medulla. These findings support the theory that upbeat nystagmus is attributable to damage to the upward vestibulo-ocular reflex pathway related to the vestibular nucleus, VTT, and interconnecting pathways.

Diffusion Tensor Tractography in Two Cases of Kernohan-Woltman Notch Phenomenon

Kernohan-Woltman notch phenomenon (KWP) is an ipsilateral motor weakness due to compression of the contralateral cerebral peduncle. We report two cases of KWP following traumatic brain injury. In case 1, ipsilateral hemiplegia was noted after right subdural hemorrhage. Although magnetic resonance imaging showed no abnormal signal changes on cerebral peduncle, diffusion tensor tractography (DTT) revealed interruption of corticospinal tract (CST) at lower level of the midbrain level. In case 2, there was abnormal signal change of the right cerebral peduncle contralateral to the primary lesion and we could not reconstruct right CST. Case 1 showed unsatisfactory motor recovery even after 15 months, and follow-up DTT showed no change. In case 2, follow-up DTT was not performed, but her ipsilateral hemiparesis had almost disappeared during the 15 months. DTT would be useful in detecting ipsilateral hemiparesis due to KWP and the clinical course may differ according to the lesion characteristics.

Somatotopic Arrangement and Location of the Corticospinal Tract in the Brainstem of the Human Brain

The corticospinal tract (CST) is the most important motor pathway in the human brain. Detailed knowledge of CST somatotopy is important in terms of rehabilitative management and invasive procedures for patients with brain injuries. In this study, I conducted a review of nine previous studies of the somatotopical location and arrangement at the brainstem in the human brain. The results of this review indicated that the hand and leg somatotopies of the CST are arranged medio-laterally in the mid to lateral portion of the cerebral peduncle, ventromedial-dorsolaterally in the pontine basis, and medio-laterally in the medullary pyramid. However, few diffusion tensor imaging (DTI) studies have been conducted on this topic, and only nine have been reported: midbrain (2 studies), pons (4 studies), and medulla (1 study). Therefore, further DTI studies should be conducted in order to expand the literature on this topic. In particular, research on midbrain and medulla should be encouraged.

Comparative topography and ultrastructure of tegument in a polyopisthocotylean parasite [Metamicrocotyla cephalus] and a monopistho-cotylean parasite [Dactylogyrus Extensus]

Comparative topography and ultrastructure was done for the tegument architecture between a polyopisthocotylean parasite [Metamicrocotyla cephalus] and a monopisthocotylean parasite [Dactylogyrus extensus] for the first time. The result showed that the tegument of M. cephalus is characterized by many foldings producing closely packed annular corrugations superimposed with a complex configuration of many robust papillae bearing microvillus-like projections, thin terminal web just underneath the apical plasma membrane, membranous projections from the basal plasma membrane inside the syncytium, one type of tegumental cell producing two tegumental secretory bodies inside the syncytium [electron-lucent bodies "ts1" and electron-dense bodies "ts2"] and the syncytium is thick [1.3-3 micro m]. The tegument of D. extensus was characterized by the weak annulations and many minute folds like microvilli, some invaginations in the apical plasma membrane form small vacuoles, eruption of some secretory bodies through the apical plasma membrane, three kinds of secretory bodies inside the syncytium from two different tegumental cells [small electron-dense granules "td1" and large fusiform moderately electron-dense bodies containing fibrous threads "td2" from one cell type and thin dumbbell-shaped electron-dense bodies "td3" from other cell type] and the syncytium is thin [1.4-1.5 micro m]. The possible functions of the distinctive features of the tegument whether presence or absence have been discussed, especially the proposed role played during the life of the parasite and the possibility of making them as characteristic features of the polyopisthocotyleans than the monopisthocotyleans

Wilson's disease with extensive white and gray matter MRI abnormalities: a case report

Wilson disease is an autosomal recessive disease, characterized by excessive accumulation of copper in the body, particularly in the liver, brain, cornea and kidney, with variable clinical manifestations. The outcome of treatment depends on early diagnosis of the disease before major irreversible tissue destruction occurs. Early diagnosis might be difficult because of its diverse clinical manifestations. We herein report on a patient with severe clinical and imaging manifestations. The patient showed cerebral atrophy and extensive abnormalities in frontal lobes, the putamen, the thalami, cerebral peduncles and posterior aspects of the occipital lobes. Such wide spread changes involving the white matter as well as the gray matter is rarely reported

Evaluation of the Somatotopic Organization of Corticospinal Tracts in the Internal Capsule and Cerebral Peduncle: Results of Diffusion-Tensor MR Tractography

OBJECTIVE: We have used diffusion tensor tractography (DTT) for the evaluation of the somatotopic organization of corticospinal tracts (CSTs) in the posterior limb of the internal capsule (PLIC) and cerebral peduncle (CP). MATERIALS AND METHODS: We imaged the brains of nine healthy right-handed subjects. We used a spin-echo echo-planar imaging (EPI) sequence with 12 diffusion-sensitized directions. DTT was calculated with an angular threshold of 35 degrees and a fractional anistropy (FA) threshold of 0.25. We determined the location of the CSTs by using two regions of interest (ROI) at expected areas of the pons and expected areas of the lateral half of the PLIC, in the left hemisphere of the brain. Fiber tracts crossing these two ROIs and the precentral gyrus (PCG) were defined as CSTs. Four new ROIs were then defined for the PCG, from the medial to lateral direction, as ROI 1 (medial) to ROI 4 (lateral). Finally, we defined each fiber tract of the CSTs between the pons and each ROI in the PCG by using two ROIs methods. RESULTS: In all subjects, the CSTs were organized along the long axis of the PLIC, and the hand fibers were located anterior to the foot fibers. The CSTs showed transverse orientation in the CP, and the hand fibers were located usually medial to the foot fibers. CONCLUSION: Corticospinal tracts are organized along the long axis of the PLIC and the horizontal direction of the CP.

Clinico-electrical Characteristics of Lateral Temporal Lobe Epilepsy; Anterior and Posterior Lateral Temporal Lobe Epilepsy

BACKGROUND AND PURPOSE: This study aimed to determine whether there are clinicoelectrical differences between anterior lateral temporal lobe epilepsy (ALTLE) and posterior lateral temporal lobe epilepsy (PLTLE), taking medial temporal lobe epilepsy (MTLE) as a reference. METHODS: We analyzed the historical information, ictal semiologies, and ictal EEGs of temporal lobe epilepsy patients with a documented favorable surgical outcome (Engel class I or II) at follow-up after more than one year. LTLE was defined when a discrete lesion on MRI or an ictal onset zone in invasive study was located outside the collateral sulcus. LTLE was further divided into ALTLE and PLTLE by reference to the line across the cerebral peduncle. Total 107 seizures of 13 ALTLE, 8 PLTLE and 21 MTLE patients were reviewed. RESULTS: Initial hypomotor symptom was frequently observed in PLTLE (P<0.001). Oroalimentary automatism (OAA) was not observed initially in PLTLE. Generalized tonic-clonic seizures occurred significantly earlier in PLTLE than in ALTLE or MTLE (P< 0.001). Ictal scalp EEG was not helpful in differentiating between ALTLE and PLTLE. CONCLUSIONS: Frequent hypomotor onset, the absence of initial oroalimentary automatism, and early generalization are characteristic findings of PLTLE, although they are insufficient to differentiate it from ALTLE or MTLE.

A Case of Central Pontine and Extrapontine Myelinolysis in a Patient with Maintenance Hemodialysis / 대한신장학회잡지

Central pontine myelinolysis (CPM) and extrapontine myelinolysis (EPM) is a rare syndrome that is clinically characterized by quadriparesis, pseudobulbar palsy, and disturbance of consciousness. It commonly occurs in patients with rapid correction of hyponatremia and chronic alcoholism. We report a case of CPM and EPM in a 55-year-old male patient with maintenance hemodialysis. He had type 2 diabetes mellitus for more than 20 years and underwent hemodialysis for the past 7 months. He was admitted for left periorbital cellulitis and uremic symptoms. On the 34th hospital day, he had nausea, vomiting, decreased consciousness, dysarthria and quadriparesis. Laboratory data were revealed as follows:glucose, 117 mg/dL; sodium, 137.1 mEq/L; and serum osmolality, 277 mosm/L. Magnetic resonance imaging (MRI) of the brain revealed increased signal intensity in the pons, upper medulla, cerebellar peduncle and cerebral peduncle in T2 weighted images. This case was considered as primary CPM and EPM occurring in a patient with maintenance hemodialysis. With general supportive care, the patient has been recovered gradually and is being followed up on an outpatient basis.

A Case of Basal Ganglia Germinoma Presenting Only with Cerebral Hemiatrophy Diagnosed by Using 11C-Methionine Positron Emission Tomography / 대한소아신경학회지

We present a case of cerebral germinoma that occurred in the basal ganglia with progressive hemiparesis. A 10-year-old boy was referred to our hospital complaining of progressive right hemiparesis and decreased mental functions. Brain MRI showed left cerebral hemiatrophy and high signal intensity in left thalamus, basal ganglia, cerebral peduncle, and pons. However, no mass or enhancement was observed. 11C-Methionine positron emission tomography showed discernable hot uptake in the left basal ganglia and thalamus. Stereotactic biopsy, with a guide of 11C-Methionine positron emission tomography, was performed and the diagnosis of pure germ cell tumor was determined. 11C-Methionine positron emission tomography is useful for localization of a suspicious tumor in patients with cerebral hemiatrophy without overt mass or enhancing lesions in brain MRI.

Diffusion Tensor MRI on Evaluation of Microstructural Abnormality Compatible with the Motor Weakness in Children with Brain Injury

We present four pediatric cases examined by diffusion tensor MRI (DTI) to investigate microstructural abnormalities of brain related to their neurologic disability and motor weakness, following absence of any remarkable lesion on the motor pathway in conventional MRI. DTI is a relatively novel MR technique that enables investigation of the orientation and integrity of white matter fiber tracts of the brain in vivo. Case 1, 2 and 3 had suffered from cerebral palsy and case 4 had developed left hemiparesis after a traumatic brain injury. Conventional brain MRI presented no specific abnormality in case 1 and 2, a focal encephalomalacia in the left anterior thalamus in case 3, and contusional hemorrhages in the left temporal and parietal lobes in case 4. But DTI disclosed microstructural abnormalities on descending motor pathway including the posterior limb of the internal capsule or the cerebral peduncle of the midbrain in all cases.

Evidence of Microstructural Abnormality on Descending Motor Pathway in Cerebral Plasied Children with Periventricular Leukomalacia: Diffusion Tensor MRI Study

OBJECTIVE: Using diffusion tensor MRI (DTI), to investigate the microstructural abnormality of corticospinal tract in the cerebral palsied children with periventricular leukomalacia on conventional MRI and to recognize the clinical usefulness of DTI. METHOD: Seven patients were studied. DTI was peformed using 1.5T MR scanner (Vision Plus, Siemens, Erlangen, Germany) and fractional anisotropies of corona radiata, posterior limbs of internal capsules, and cerebral peduncles of midbrain in both hemisphere were calculated. RESULTS: The fractional anisotropy was significantly decreased in all corona radiata, posterior limbs of internal capsules, cerebral peduncles of midbrain in six patients except one hemiplegic patient, compared with that of control group. In in the hemiplegic patient, the fractional anisotropy was reduced only in affected hemisphere. In addition, the fractional anisotropy tended to be also increased as gross motor function measure (GMFM) score was increased. CONCLUSION: We believe that DTI may be efficient in evaluating microstructural abnormality on the motor pathway of brain and helpful in providing prognosis of clinical findings in cerebral palsied children with periventricular leukomalacia.

Ultrastructural studies on the tegument of dicrocoelium dendriticum [Rudolphi, 1819] loss 1899

The tegument of Dicrocoelium dendriticum was studied by scanning and transmission electron microcopy. It consists of an anucleate surface syncytium and a deeper nucleated zone. The syncytial layer covers the entire surface of the fluke. It is connected to the nucleated zone through thin cytoplasmic strands. The syncytium is bounded by an apical plasma membrane, which is highly folded. This layer mainly contains abundant mitochondria of varying size and shape as well as two types of granules, dumbbell shaped and spherical. Although the apical surface shows active exocytosis, no evidence for endocytosis was observed. This study revealed the presence of this liver fluke in sheep imported from other counties

Morphine releases glutamate through AMPA receptors in the ventral tegmental area: a microdialysis study in conscious rats

In vivo microdialysis was used to study the effects of morphine on glutamate release from the ventral tegmentum area [VTA] in freely moving rats. Intraperitoneal [i.p.] injection of acute and repeated morphine at increasing doses significantly enhanced glutamate release. Only a minor tolerance developed to this dosage of morphine. AP-5 [2-amino-5-phosphonovaleric acid, 0.5 mg/kg i.p.], a NMDA receptor antagonist, given 20 min before each repeated morphine injection, did not have a significant effect on the stimulated glutamate release. Conversely, injection of CNQX [6-cyano-7-nitroquinoxaline-2, 3-dione, 0.5 mg/kg i.p.], an AMPA receptor antagonist, 20 min before each morphine dose was found to markedly inhibit morphine-induced glutamate release in the VTA. In all experiments, glutamate release reduced by time. These results show for the first time that acute and repeated injection of morphine stimulates glutamate release in the conscious rat VTA via AMPA receptors

Age-Related Changes of MHC Class II-immunoreactive Dendritic Cells in Rat Brain / 대한소아신경학회지

PURPOSE: Dendritic cells are antigen presenting cells(APC) that express class II major histocompatibility complex gene products on their surface. Recently, it was proved that dendritic cells activate antitumor immunity for intracranial germ cell tumor. The aim of the present study is to investigate the age-related changes of MHC class II-immunoreactive dendritic cells in the rat brain. METHODS: Male rats(Sprague-Dawley) were sacrificed at 1 month, 12 months and 24 months after birth. Brains were removed and sliced in rat brain matrix. Brain slices were cryosectioned coronally at interaural 5.70-6.70 mm. Brain tissue sections were immunohistochemically reacted with monoclonal MHC class II antibody. RESULTS: MHC class II-immunoreactive dendritic cells were observed in choroid plexuses and white matter(corpus callosum, cerebral peduncle and external capsule). The number of MHC class II-immunoreactive dendritic cells was slightly increased with age. As age increases, shapes of MHC class II-immunoreactive dendritic cells became more complex and aggregated together. CONCLUSION: As age increases, MHC class II-immunoreactive dendritic cells in choroid plexuses and white matter of the brain became not only more complex in shape, but also increased in number to improve immunity.

Leigh Syndrome: Clinical, Radiological, and Mitochondrial Mutational Study / 대한소아신경학회지

PURPOSE: Leigh syndrome is a subacute neurodegenerative disorder of infancy or early childhood characterized by variable clinical manifestations and characteristic pathologic findings on brain. The characteristic radiological findings revealed bilateral symmetrical high signal intensity in T2-weighted brain MRI imaging. The previous studies reported defects of enzymes involved in aerobic energy metabolism or point mutations in mitochondrial deoxyribonucleic acid(mtDNA), including a T-to-C or T-to-G mutation at nucleotide position(nt) 8993 or 9176 located in adenosinetriphosphatase(ATPase) 6 gene of mtDNA. Therefore, we studied the characteristic clinical, radiological, and genetical findings of Leigh syndrome, diagnosed at the Department of Pediatrics, Asan Medical Center. METHODS: From August 1992 to June 2000, 17 patients were included in this study, who presented charateristic MRI findings of Leigh syndrome. We examined the concentrations of lactate and pyruvate in blood and cerebrospinal fluid(CSF), and obtained MRS from 12 patients. For mutational analysis, fibroblasts from skin biopy were obtained from 17 patients. We analyzed the T8993C or T9176C mutation at ATPase 6 gene. RESULTS: The male to female ratio is 12 to 5, and the age of onset is from 2 month to 8 year. Among the total 17 patients, 4 patients died, 4 patients alive yet, and 9 patients were unable to be followed up. The clinical manifestations were developmental delay or retardation(n=11, 64.7%), respiratory difficulty(n=10, 58.8%), altered consciousness (n=7, 41.2%), strabismus or ophthalmoplegia(n=5, 29.4%), feeding difficulty(n=5, 29.4%), etc. T2-weighted brain MRI showed bilateral high signal intensity in basal ganglia, brainstem, thalamus, periaqueductal gray matter, cerebral peduncle, substantia nigra, cerebellum, subcortical white matter. MRS was performed on 12 patients and showed lactate peak increase in ten patients(83.3%) and N-acetylaspartate peak decrease in two patients (16.7%). The concentrations of lactate and pyruvate in CSF and blood were obtained, and lactate/pyruvate ratio was calculated. We observed the elevation of ratio in 3(33.3%) of 9 cases in CSF, 7(63.6%) of 11 cases in blood, respectively. Our mutation analysis revealed that T8993C mutation in one patient and T9176C mutation in another patient were confirmed among the total 17 patients. CONCLUSION: Our study confirmed a case of the T8993C and a case of the T9176C mutation among 17 patients of Leigh syndrome. Therefore, Leigh syndrome is a genetically heterogenous disorder and further genetic study will be needed.

A Case of Tonic Spasm Presenting as Sole Manifestation of Multiple Sclerosis

A young woman developed a hemilateral tonic spasm associated with multiple sclerosis. Her symptoms included brief recurrent episodes of abnormal, often painful, posturing of one or more extremities without alteration of consciousness. An area of demyelination in the contralateral cerebral peduncle was observed on a magnetic resonance imaging. The tonic attacks abated with carbamazepine therapy. The pathophysiology may involve ephaptic transmission between demyelinated fibers in acute plaques within the corticospinal tract secondary to axonal irritation by lymphokines. (J Korean Neurol Assoc 19(2):167~169, 2001)

A Case of Tonic Spasm Presenting as Sole Manifestation of Multiple Sclerosis

A young woman developed a hemilateral tonic spasm associated with multiple sclerosis. Her symptoms included brief recurrent episodes of abnormal, often painful, posturing of one or more extremities without alteration of consciousness. An area of demyelination in the contralateral cerebral peduncle was observed on a magnetic resonance imaging. The tonic attacks abated with carbamazepine therapy. The pathophysiology may involve ephaptic transmission between demyelinated fibers in acute plaques within the corticospinal tract secondary to axonal irritation by lymphokines. (J Korean Neurol Assoc 19(2):167~169, 2001)

Parálisis supranuclear progresiva / Progressive supranuclear palsy

La parálisis supranuclear progresiva (PSP), también llamada síndrome de Steele-Richardson-Olszewski, es uno de los síndromes parkinsionanos atípicos más frecuentes. Es una afección degenerativa de causa desconocida caracterizada por atrofia del tegmentum protuberancial y mesencéfalo, decoloración de la sustancia nigra y relativo respeto de la corteza cerebral. Existe un consenso sobre la dificultad para llegar al diagnóstico de certeza tanto clínico como patológico. Ha habido casos de PSP clínica cuyas autopsias no confirmaron el diagnóstico, y autopsias con hallazgos diagnósticos de PSP que fueron interpretados clínicamente como otros padecimientos o síndromes degenerativos. En Latinoamérica no existen estadísticas epidemiológicas sobre esta entidad nosológica y en Chile no se ha publicado ningún caso hasta la fecha. El objetivo del presente reporte es la presentación de seis casos que cumplen con los criterios diagnósticos establecidos por el National Institute of Neurological Disorders and Stroke and The Society for PSP (NINDS-SPSP) en 1996. Se concluye, a partir del presente trabajo que la PSP no es excepcional en nuestro medio y que debe considerarse entre los diagnósticos diferenciales de los síndromes parkinsonianos