Biomedical subjects

Kousaku Ohno

Publications and source records attributed to Kousaku Ohno.

At least 19 recordsLinked to original sources

PubMed2007

Serial diffusion-weighted MRI in hemorrhagic shock and encephalopathy syndrome.

This report presents a case of hemorrhagic shock and encephalopathy syndrome. In the acute stage, brain magnetic resonance imaging demonstrated symmetrical hyperintensity on diffusion-weighted images and hypointensity on the apparent diffusion coefficient maps in the subcortical white matter. Whereas the abnormal diffusion-weighted imaging signals of the white matter resolved in the subacute stage, the adjacent gray matter became hyperintense on diffusion-weighted images and hypointense on apparent diffusion coefficient maps. The evolution of diffusion-weighted imaging signals is thus considered to be one of the early findings in hemorrhagic shock and encephalopathy syndrome.

Brain↗

PubMed2006

A patient with simplified gyral pattern followed by progressive brain atrophy.

We present the case of a three-year-old boy who suffered from intractable epilepsy from birth, and who displayed microcephaly and severe developmental delay. Neuroradiological examination revealed the presence of simplified gyri of the cerebral cortex, and increased signal intensity changes in the cerebral white matter on T2-weighted magnetic resonance imaging. A tentative diagnosis of congenital cortical malformation was made, but unexpectedly, the cerebrum, cerebellum, and pons showed a progressive atrophy during the follow-up period. The basal ganglia and thalamus were relatively spared. Investigations could find no evidence of leukodystrophies, metabolic disorders, hereditary brain anomalies, or congenital central nervous infections. This case may represent a novel type of neurodegenerative disease with malformation of cortical development.

Atrophy↗

PubMed2006

Neural substrates of sarcasm: a functional magnetic-resonance imaging study.

The understanding of sarcasm reflects a complex process, which involves recognizing the beliefs of the speaker. There is a clear association between deficits in mentalizing, which is the ability to understand other people's behavior in terms of their mental state, and the understanding of sarcasm in individuals with autistic spectrum disorders. This suggests that mentalizing is important in pragmatic non-literal language comprehension. To highlight the neural substrates of sarcasm, 20 normal adult volunteers underwent functional magnetic-resonance imaging. We used scenario-reading tasks, in which sentences describing a certain situation were presented, followed by the protagonist's comments regarding that situation. Depending on the situation, the semantic content of the comments was classified as sarcastic, non-sarcastic, or contextually unconnected. As the combination of the first and second sentences represented discourse-level information that was not encoded in the individual sentences, sarcasm detection was represented as the differential activation induced by the second sentences. Sarcasm detection activated the left temporal pole, the superior temporal sulcus, the medial prefrontal cortex, and the inferior frontal gyrus (Brodmann's area [BA] 47). The left BA 47 was activated more prominently by sarcasm detection than by the first sentence. These findings indicate that the detection of sarcasm recruits the medial prefrontal cortex, which is part of the mentalizing system, as well as the neural substrates involved in reading sentences. The left BA 47 might therefore be where mentalizing and language processes interact during sarcasm detection.

Adolescent↗

PubMed2006

Disappearance of frontal N30 component of median nerve stimulated SSEPs in two young children with abnormal striatal lesions.

Median nerve stimulated short-latency somatosensory evoked potentials (MN-SSEPs) were performed in two young children with extrapyramidal symptoms. Brain MRI showed bilaterally symmetric striatal lesions in both cases. The subcortical components (N9, N11, N13, N18, P11, and P13) and the parietal component (N20) were normally detected, whereas the frontal component (N30) was not detected bilaterally in either case. In conclusion, our findings suggest that frontal N30 disappearance could be observed since as early as young childhood and it may pathophysiologically reflect severe dysfunction in the extrapyramidal system.

Brain Injuries↗

PubMed2006

Facioscapulohumeral muscular dystrophy with severe mental retardation and epilepsy.

We report here a case of a 20-year-old woman with facioscapulohumeral muscular dystrophy (FSHD). In this patient, the involvement of facial muscle had been present since early childhood, but obscured due to the complication of profound mental retardation. Epilepsy emerged at eight years of age. Symmetrical limb muscle weakness appeared at 15 years of age, which progressed such that she was wheelchair-bound at 18 years of age. An elevated serum creatine kinase, predominant involvement of hamstrings, scapular and abdominal muscles, as well as an impaired stapedial reflex at high tune, were compatible with the clinical features of FSHD. The diagnosis of 4q35-FSHD was confirmed by detection of a 10kb EcoRI fragment with a p13E-11 probe on a Southern blot. The intellectual disability in this patient was the most severe of all FSHD patients reported to date and has hindered a correct diagnosis. This entity should be included in the differential diagnoses for patients with muscular symptoms and accompanying mental retardation.

Adult↗

PubMed2006

Delayed neuropsychiatric syndrome in a child following carbon monoxide poisoning.

Here, we report the case of a five-year-old boy with carbonic monoxide (CO) poisoning. The patient initially recovered after the initiation of hyperbaric oxygen (HBO) therapy, but lethargy as well as visual and gait disturbances appeared two days later. Left hemiparesis and mood lability also subsequently appeared. Slow frontal activity was noted on electroencephalography, while fluid-attenuation inversion recovery and diffusion-weighted magnetic resonance imaging (MRI) revealed high signal-intensity lesions in the hippocampus and deeper layers of the occipital and frontal cerebral cortex. The neurological symptoms subsided gradually during the 10-day course of HBO therapy, but the left-hand paresis and quadrantic hemianopsia persisted, in association with impaired attention, slow mental processing, and incontinence. Lesions in the globus pallidum were noted on follow-up MRI at 14 days, and cortical lesions became evident as linear, low signal-intensity areas on T1-weighted imaging 4 months after presentation. Delayed neuropsychiatric syndrome in CO poisoning is rare in childhood, although children should be carefully monitored after CO exposure. The finding of cortical laminar necrosis in this patient is quite atypical in CO poisoning, and suggests a broader and previously nonpredicted pathomechanism in this condition.

Carbon Monoxide Poisoning↗

PubMed2006

Acute encephalitis with refractory, repetitive partial seizures: case reports of this unusual post-encephalitic epilepsy.

We report on three acute encephalitis patients with refractory, repetitive partial seizures (AERRPS). All three suffered acute febrile episodes associated with status epilepticus, which necessitated high-dose barbiturate therapy under artificial ventilation for several weeks. Electroencephalography (EEG) revealed a predominance of diffuse epileptiform discharges initially, subsequently developing into periodic bursts of these discharges. Reduction of the barbiturate dosage resulted in clinical and subclinical partial seizures appearing repetitively in clusters. Prolonged fever persisted for 2-3 months, even several weeks after normalization of cell counts in the cerebrospinal fluid. The EEG showed an improvement after resolution of this fever, and seizures became less frequent, although still intractable. Oral administration of high-dose barbiturate and benzodiazepines were partially effective during the acute phase, and a barbiturate dependency, lasting for years, was noted in one patient. Steroid administration was effective in stopping the febrile episodes in one patient, with concurrent improvement in seizure control. Magnetic resonance imaging showed enhancement of bitemporal cortical areas in one patient, and high signal intensity on T2 weighted image in the bilateral claustrum in another patient. Diffuse cortical atrophy appeared within two months after the onset of encephalitis in all patients. The evolution of the seizures and EEG findings suggested a high degree of cortical excitability in AERRPS. In this report, we propose a tentative therapeutic regimen for seizure control in this condition. We also hypothesize that a prolonged inflammatory process exists in the cerebral cortex with AERRPS, and may be pivotal in the epileptogenesis.

Acute Disease↗

PubMed2006

Lower brainstem dysfunction in an infant with persistent primitive trigeminal artery.

A 6-month-old boy with persistent primitive trigeminal artery (PPTA) presented with stridor, dysphagia, delayed motor development and postural neck and shoulder dystonia. Magnetic resonance imaging/angiography and ultrasonography revealed PPTA, with flow from the dilated basilar artery to the right internal carotid artery, lower brainstem compression by the dilated basilar artery, and cerebellar vermis hypoplasia. Evoked potentials showed lower pons and medulla oblongata functional disruption. These lesions may be related to vascular etiology in the lower brainstem or to congenital malformation syndrome involving infratentorial structures. The relationship of this condition to Möbius syndrome is discussed.

Abnormalities, Multiple↗

PubMed2006

Familial limb pain in childhood: unusual manifestation of migraine?

A familial case of limb pain is described. Frequent vascular pain appeared during early childhood in affected individuals, often with predominance in the lower extremities. This pain subsided in patients during adolescence, when they began to suffer from typical migraine. The limb pain was moderate to severe, and refractory to analgesic and anti-migraine medications. Limb temperature was cold at the onset of pain, and became warm during the painful attacks. Plasma substance P and calcitonin gene-related peptide were elevated during the episodic pain. We propose this condition is a new precursor etiology of migraine, with possible autosomal dominant inheritance.

Analgesics↗

PubMed2006

Cholesterol depletion facilitates ubiquitylation of NPC1 and its association with SKD1/Vps4.

Niemann-Pick disease type C (NPC) is an inherited lipid storage disorder caused by mutations in NPC1 or NPC2. NPC1 is a polytopic glycoprotein that contains a sterol-sensing domain, whereas NPC2 is a soluble protein that contains an MD-2-like lipid-recognition domain. In the current study, we addressed the hypothesis that ubiquitylation of NPC1 might be regulated by cholesterol. We found that depletion of cellular cholesterol facilitated ubiquitylation of NPC1 expressed in COS cells. A loss-of-function mutant, NPC1(P691S), which contains an amino acid substitution in the sterol-sensing domain, failed to respond to cholesterol depletion. Another mutant, NPC1(deltaLLNF), which lacks the endosomal-targeting motif, also failed to respond. SKD1(E235Q), a dominant-negative mutant of SKD1/Vps4 that inhibits disassembly of the endosomal sorting complex required for transport (ESCRT), caused an accumulation of ubiquitylated NPC1. SKD1(E235Q) associated with NPC1 on the endosomal membrane, whereas wild-type SKD1 associated with NPC1 only when cells were depleted of cholesterol. Similarly, in control human skin fibroblasts, cholesterol depletion facilitated ubiquitylation of endogenous NPC1. In patient cells that lack NPC2 function, NPC1 was ubiquitylated regardless of cellular cholesterol levels, suggesting that NPC2 is required to prevent NPC1 ubiquitylation under cholesterol-rich conditions. These results suggest that ubiquitylation of NPC1 and its association with the ESCRT complex are controlled by endosomal cholesterol levels utilizing a mechanism that involves NPC2.

ATPases Associated with Diverse Cellular Activitie↗

PubMed2006

A neuropeptide ligand of the G protein-coupled receptor GPR103 regulates feeding, behavioral arousal, and blood pressure in mice.

Here, we report the isolation and characterization of an endogenous peptide ligand of GPR103 from rat brains. The purified peptide was found to be the 43-residue RF-amide peptide QRFP. We also describe two mouse homologues of human GPR103, termed mouse GPR103A and GPR103B. QRFP binds and activates the human GPR103, as well as mouse GPR103A and GPR103B, with nanomolar affinities in transfected cells. Systematic in situ hybridization analysis in mouse brains showed that QRFP is expressed exclusively in the periventricular and lateral hypothalamus, whereas the two receptor mRNAs are distinctly localized in various brain areas without an overlap to each other. When administered centrally in mice, QRFP induced feeding behavior, accompanied by increased general locomotor activity and metabolic rate. QRFP-induced food intake was abolished by preadministration of BIBP3226, a specific antagonist for the Y1 neuropeptide Y receptor. Hypothalamic prepro-QRFP mRNA expression was up-regulated upon fasting and in genetically obese ob/ob and db/db mice. Central QRFP administration also evoked highly sustained elevation of blood pressure and heart rate. Our findings suggest that QRFP and GPR103A/B may regulate diverse neuroendocrine and behavioral functions and implicate this neuropeptide system in metabolic syndrome.

Amino Acid Sequence↗

PubMed2006

Altered glycosylation of alpha-dystroglycan in neurons of Fukuyama congenital muscular dystrophy brains.

To test the hypothesis that the disruption of fukutin protein produces the brain pathology through hypoglycosylation of alpha-dystroglycan (alpha-DG), we immunostained Fukuyama congenital muscular dystrophy (FCMD) brains with an antibody that recognizes the polysaccharide epitope of alpha-DG. Immunoreactivity of the glia-limitans along the cortical surface, as well as that of the glial endfeet around vessel walls, was preserved in the FCMD cerebrum. However, fragmentation of the immunostained glia-limitans was noted in association with parenchymal protrusion and gyral fusion. In the FCMD cerebellum, this fragmentation of alpha-DG labeling was limited to the area of micropolygyria, and immunostaining at the glia-limitans and vessel walls was comparable to that of the control brains, in structurally normal areas. In the hippocampus, neurons of the dentate gyrus and corpus ammonis were immunopositive for alpha-DG in control subjects, but this staining was markedly decreased in FCMD brains. In contrast, immunolabeling of blood vessels and the glia-limitans was preserved in this region. Fukutin antisera clearly labeled hippocampal neurons in control brains, while this labeling was decreased in FCMD brains. Thus, hypoglycosylation of alpha-DG was evident in neurons, but not in the glial cell population of FCMD brains. This suggests that the mechanism of alpha-DG glycosylation may differ between neurons and glial cells, and that a fukutin gene defect may result in functional disruption through hypoglycosylation of both neuronal and glial alpha-DG.

Adolescent↗

PubMed2006

Monozygotic twins discordant for Klippel-Feil syndrome.

In a pair of Japanese monozygotic twins, one manifested Klippel-Feil syndrome, a short neck with C(1-4) vertebra fusion, whereas the other was normal. The discordance between the twins suggests that Klippel-Feil syndrome results in part from a postzygotic somatic mutation or intrauterine environmental factors.

Diseases in Twins↗

PubMed2006

Magnetoencephalography in patients with tuberous sclerosis and localization-related epilepsy.

PURPOSE: To clarify the usefulness of magnetoencephalography (MEG) for diagnosis of the spatial relations between spike foci and suspicious epileptogenic tubers on MRI in patients with tuberous sclerosis (TS) and to compare MEG spike foci with single-photon emission computed tomography (SPECT) findings. METHODS: We analyzed magnetic fields of epileptic spike discharges in 15 patients with TS and localization-related epilepsy (LRE) by using MEG (a whole-head 204-channel magnetometer system). We investigated the spatial relation between the equivalent current dipoles (ECDs) of interictal spike discharges and visible cortical tubers on MRI. We also compared results of MEG and MRI with SPECT findings. RESULTS: MEG detected a cluster of ECDs around one cortical tuber in six of 15 patients and clusters of ECDs around two cortical tubers in five patients. Interictal SPECT was disappointing in detection of epileptic foci in TS. However, MEG spike foci showed spatial consistency with ictal hyperperfusion areas in two patients. Three patients with single ECD clusters underwent surgical treatment: two have been seizure free, and one has obtained seizure reduction of >90%. CONCLUSIONS: ECDs were located around visible tuber nodules. MEG enabled precise localization of the epileptic foci and provided crucial information for surgical treatment in patients with TS and partial epilepsy. TS patients showing a single ECD cluster on MEG may be appropriate candidates for surgical treatment.

Adolescent↗

PubMed2006

[Polycystic ovary syndrome and hepatocellular adenoma related to long-term use of sodium valproate in a young woman].

Previous studies have reported a high prevalence of polycystic ovary syndrome (PCOS) among women taking sodium valproate (VPA). We report the case of a 28 year-old epileptic female taking VPA, who developed PCOS and later hepatocellular adenoma. She had been taking VPA for intractable epilepsy since the age of 15 months. At the age of 22 years, she suffered spontaneous rupture of a liver tumor that was diagnosed as hepatocellular adenoma. At the age of 24 years, bilateral polycystic ovaries were found by transabdominal ultrasonography, and PCOS was diagnosed. VPA may directly influence steroidogenesis in the ovary and cause hyperandrogenemia with ensuing PCOS. It is known that abnormality in the sex hormones contributes to the onset of hepatocellular adenoma. Therefore, we speculate that hyperandrogenemia due to VPA contributed to the development of hepatocellular adenoma in this case.

Adenoma, Liver Cell↗

PubMed2006

[Pulmonary atelectasis in patients with neurological or muscular disease; gravity-related lung compression by the heart and intra-abdominal organs on persistent supine position].

We report 10 cases of pulmonary atelectasis diagnosed by chest computed tomography in patients with neurological or muscular disease. Atelectasis was frequently seen in hypotonic patients who could not roll over on their own. The atelectases located mostly in the dorsal bronchopulmonary segments, adjacent to the heart or diaphragm. Atelectasis diminished in two patients after they became able to roll themselves over. Gravity-related lung compression by the heart and intra-abdominal organs on persistent supine position can cause pulmonary atelectasis in patients with neurological or muscular disease who can not roll over by their own power. To confirm that the prone position reduces compression of the lungs, chest computed tomography was performed in both the supine and the prone position in three patients. Sagittal images with three-dimensional computed tomographic reconstruction revealed significant sternad displacements of the heart and caudal displacements of the dorsal portion of the diaphragm on prone position compared with supine position. The prone position, motor exercises for rolling over, and biphasic cuirass ventilation are effective in reducing gravity-related lung compression. Some patients with intellectual disabilities were also able to cooperate in chest physiotherapy. Chest physiotherapy is useful in preventing atelectasis in patients with neurological or muscular disease.

Abdomen↗

PubMed2006

[Influenza-associated encephalopathy with onset of prolonged convulsion: a case report].

A 1-year-old girl with influenza-associated encephalopathy initially exhibited prolonged febrile convulsions and subsequent drowsiness. She became unconsciousness and experienced a cluster of seizures 4 days later. Diffusion-weighted magnetic resonance imaging (DWI) showed high signal intensity in the bilateral frontal white matter. This signal change migrated to the bifrontal cortical areas and the caudate nuclei within 10 days, when T2 elongation appeared over the gray and white matter of frontal lobes. Choreoathetosis and oculogyric crisis were transiently noted at this period. Frontal lobe signs, including the forded mouth opening response, after diminution of these movement disorders. The DWI signal change subsequently resolved and frontal cortical atrophy appeared thereafter. Levels of inflammatory cytokines in the cerebrospinal fluid were normal during the acute phase of clinical course. The biphasic clinical course with initial prolonged seizure, involvement of the frontal lobes, and the progression of signal change on DWI from white to gray matter, meets the characteristics of "status epilepticus-type acute encephalopathy" suggested by Shiomi et al. Although pentobarbital infusion, steroid pulse therapy and mild hypothermia did not show any apparent effects on the clinical course of this patient, further trial of these therapies may be warranted for the treatment of this type of encephalopathy.

Diffusion Magnetic Resonance Imaging↗

PubMed2005

Arthrogryposis multiplex congenita with callosal agenesis and dentato-olivary dysplasia.

We report the autopsy case of a boy with arthrogryposis multiplex congenita, associated with callosal agenesis and dentato-olivary dysplasia. The patient manifested with dysmorphic facial features and suffered from intractable epilepsy during the neonatal period. These sets of complications suggest that a common molecular mechanism may be involved in the development of corpus callosum and the folding of the dentate and inferior olivary nuclei. Deep brain structures, including the brainstem and the cerebellum, may be involved in the pathophysiology of symptomatic generalized epilepsy. The differential diagnoses for the clinical and pathological characteristics of this patient are discussed.

Agenesis of Corpus Callosum↗