Biomedical subjects

S Takashima

Publications and source records attributed to S Takashima.

At least 109 records · Page 6Linked to original sources

PubMed2000

Enhanced GAP-43 gene expression in cortical dysplasia.

Growth-associated protein GAP-43, a phosphoprotein enriched at presynaptic nerve terminals, is thought to be involved in axonal outgrowth and plasticity in synaptic connections. To explore the synaptic remodeling under the epileptic conditions, we examined GAP-43 expression in brain specimens surgically resected as epileptogenic foci from 17 patients with cortical dysplasia. In situ hybridization with GAP-43 antisense riboprobe showed significantly increased signals in the dysplastic large neurons of cortical dysplasia. Specific distribution with increased immunoreactivity for GAP-43 was not shown in the dysplastic cortex. These results suggest that GAP-43 gene expression is over-expressed in the dysplastic large neurons, reflecting activated synaptic remodeling in the epileptic condition of cortical dysplasia, although the precise site of accelerated synaptic rearrangement remains unknown.

Cerebral Cortex↗

PubMed2000

Redefined substrate specificity of ST6GalNAc II: a second candidate sialyl-Tn synthase.

The acceptor substrate specificities of ST6GalNAc I and II, which act on the synthesis of O-linked oligosaccharides, were reexamined using ovine submaxillary mucin, [Ala-Thr(GalNAc)-Ala]n polymer (n = 7-11). It has been suggested that only ST6GalNAc I can synthesize carbohydrate structures of sialyl-Tn-antigen; i.e., NeuAc alpha2-6GalNAc-O-Thr/Ser [Kurosawa et al., J. Biol. Chem. 269, 19048-19053 (1994)] based on the result that ST6GalNAc I, not ST6GalNAc II, exhibited activity toward asialoagalacto-fetuin. In this study, we present evidence that both ST6GalNAc I and II exhibit activity toward asialo-OSM (ovine submaxillary mucin) and [Ala-Thr(GalNAc)-Ala]n polymer (n = 7-11) which have only the GalNAc-O-Thr/Ser-structures. These results strongly indicate that not only ST6GalNAc I but also II are candidates for sialyl-Tn synthases.

Animals↗

PubMed2000

Localization of Bcl-xbeta in the developing and adult rat central nervous system.

bcl-xbeta is a novel apoptosis-regulating member of the bcl-x family that has recently been isolated from rats and mice. To explore the functional role of Bcl-xbeta, we raised a monoclonal antibody against rat Bcl-xbeta protein and investigated the cellular localization of the molecule in the rat CNS. Immunohistochemistry revealed that, in the fetal and neonatal stages, Bcl-xbeta was intensively and widely expressed in the CNS. Many neurons in the diencephalon and brain stem showed intense cytoplasmic labeling. The immunoreactivity decreased during the postnatal development and reached to the level of adulthood by P14. In the adult brain and spinal cord, labeling was restricted to specific types of neurons and distributed throughout their somata and dendrites. Weak immunoreactivity was present in many CNS regions such as the cerebral cortex, hippocampal dentate gyrus, caudate-putamen, globus pallidus, thalamus, locus ceruleus, pontine nuclei, inferior olive, reticular formation, cerebellar cortex and spinal anterior horn. Amygdaloid nuclei and hippocampal CA1 to CA3 sectors showed restricted expression of Bcl-xbeta in a subset of neurons. Neuronal labeling was almost undetectable in several regions, including the piriform cortex, hypothalamus, posterior column nuclei and spinal posterior horn. These results suggest that Bcl-xbeta plays an important role throughout the CNS in developing stage and may regulate the apoptosis of postnatal CNS neurons.

Animals↗

PubMed2000

Immunohistochemical expression of doublecortin in the human cerebrum: comparison of normal development and neuronal migration disorders.

Immunohistochemical expression of the doublecortin (DCX) gene product was investigated in cerebral cortices from 33 normal developing human, aged 9 gestational weeks (GW) to 29 years, and from 26 patients with various neuronal migration disorders, aged 19 GW to 34 years. DCX immunoreactivity was detected predominantly in the fetal cerebral cortex. The neurons in the cortical plate (CP) exhibited positive labeling at 9 GW. Staining was the most marked intense at 12-20 GW, and gradually decreased thereafter, only relatively weak immunoreactivity remaining in pyramidal cells. Comparison of the immunohistochemical characteristics of DCX and those of nestin and vimentin indicated the early expression of DCX in neuroepithelial stem cells of the subventricular germinal layer, as well as in neurons of the CP. The most marked intense expression in the period of neuronal migration strongly indicated its role in neuronal migration. The abnormal distribution of DCX immunolabeling in the cerebral cortex was associated with a neuronal disarrangement in some migration disorders, such as Miller-Dieker syndrome and Fukuyama congenital muscular dystrophy. Decreased DCX immunolabeling was demonstrated in fetuses and infants with Zellweger syndrome, implicating DCX in the neuronal migration abnormality in this syndrome.

Adolescent↗

PubMed2000

Rapid immunologic diagnosis of classic late infantile neuronal ceroid lipofuscinosis.

OBJECTIVE: To establish a new method for rapid diagnosis of late infantile neuronal ceroid lipofuscinosis (LINCL, CLN2) using specific polyclonal antibodies against the CLN2 gene product. METHODS: Cells and tissues were obtained from five patients with LINCL, two with variant type NCL, three with other lysosomal storage diseases, and eight control subjects. Two antibodies were raised against N- and C-terminal peptide fragments of the normal product of the CLN2 gene. The authors examined the possibility of diagnosis of LINCL with immunostaining and immunoblotting using specific antibodies made of the recently identified defective gene in LINCL. RESULTS: Immunoreactivity with these antibodies showed the absence or marked reduction of CLN2 immunoreactivity in the lymphocytes, lymphoblasts, and fibroblasts of all five patients with LINCL examined. CONCLUSIONS: These results indicate the usefulness of this diagnostic method based on the changes in CLN2 immunoreactivity. This relatively simple, specific, and cost-effective method is a promising diagnostic tool for this disease, although additional studies are necessary.

Aminopeptidases↗

PubMed2000

Identification of a natural soluble neuropilin-1 that binds vascular endothelial growth factor: In vivo expression and antitumor activity.

Neuropilin-1 (NRP1) is a 130-kDa transmembrane receptor for semaphorins, mediators of neuronal guidance, and for vascular endothelial growth factor 165 (VEGF(165)), an angiogenesis factor. A 2.2-kb truncated NRP1 cDNA was cloned that encodes a 644-aa soluble NRP1 (sNRP1) isoform containing just the a/CUB and b/coagulation factor homology extracellular domains of NRP1. sNRP1 is secreted by cells as a 90-kDa protein that binds VEGF(165), but not VEGF(121). It inhibits (125)I-VEGF(165) binding to endothelial and tumor cells and VEGF(165)-induced tyrosine phosphorylation of KDR in endothelial cells. The 3' end of sNRP1 cDNA contains a unique, 28-bp intron-derived sequence that is absent in full-length NRP1 cDNA. Using a probe corresponding to this unique sequence, sNRP1 mRNA could be detected by in situ hybridization differentially from full-length NRP1 mRNA, for example, in cells of liver, kidney, skin, and breast. Analysis of blood vessels in situ showed that NRP1, but not sNRP1, was expressed. sNRP1 was functional in vivo. Unlike control tumors, tumors of rat prostate carcinoma cells expressing recombinant sNRP1 were characterized by extensive hemorrhage, damaged vessels, and apoptotic tumor cells. These results demonstrate the existence of a naturally occurring, soluble NRP1 that is expressed differently from intact NRP1 and that appears to be a VEGF(165) antagonist.

Animals↗

PubMed2000

Developmental and pathological expression of peroxisomal enzymes: their relationship of D-bifunctional protein deficiency and Zellweger syndrome.

We present the developmental changes of peroxisomal enzymes, catalase, L-bifunctional protein (L-BF) and D-bifunctional protein (D-BF), in the normal brains, and patients with D-BF deficiency, a new peroxisomal disease. D-BF immunoreactivity was observed in controls as early as 13 gestational weeks (GW) and increased with maturation. The adult pattern with fine granule staining of somata and dendrites became apparent in adolescence. L-BF appeared at 20 GW in the cerebral cortex and Purkinje cells and positive glia appeared early in the white matter at 17 GW, and then increased with age. Catalase-positive neurons were identified in the same manner as L-BF, D-BF deficiency in both fetus and infant showed markedly diminished enzyme immunoreactivity. Patients demonstrate reduced D-BF expression. Zellweger syndrome shows decreased expression for the three proteins. This study shows that the peroxisomal enzymes may be closely related to neuronal maturation and gliogenesis in human brain and to disturbance of neuronal migration as seen in Zellweger syndrome significant. D-BF deficiency may exhibit a range of symptoms during the neonatal and early infantile periods some of which may be similar to Zellweger syndrome.

17-Hydroxysteroid Dehydrogenases↗

PubMed2000

Nifedipine-induced coronary vasodilation in ischemic hearts is attributable to bradykinin- and NO-dependent mechanisms in dogs.

BACKGROUND: Dihydropyridine calcium channel blockers protect endothelial cells against ischemia and reperfusion injury, suggesting that nifedipine may increase the in vivo cardiac NO level and thus coronary blood flow (CBF) in ischemic hearts. We tested this hypothesis. METHODS AND RESULTS: In open-chest dogs, coronary perfusion pressure (CPP) was reduced in the left anterior descending coronary artery so that CBF decreased to one third of the control level, and thereafter CPP was maintained constant (103+/-8 to 43+/-3 mm Hg, n=9). We obtained fractional shortening (FS) and lactate extraction ratio (LER) as indices of regional myocardial contraction and metabolism. Both FS (26.4+/-2.1% to 6.7+/-2.0%, n=9, P<0.001) and LER (32+/-6% to -37+/-5%, n=9, P<0.001) showed a decrease when CPP was reduced. After intracoronary infusion of nifedipine (4 microgram. kg(-1). min(-1)), CBF increased from 30+/-1 to 48+/-4 mL. 100 g(-1). min(-1) (P<0.01) without a change of CPP (n=9). Both FS (14.0+/-1.9%, n=9) and LER (-9+/-7%, n=9) also increased (P<0.01). Nifedipine increased the difference in the level of metabolites of NO (nitrate+nitrite; 9+/-3 to 25+/-5 nmol/mL, n=9, P<0.01) and bradykinin (22+/-5 to 58+/-4 pmol/mL, n=9, P<0.01) between coronary venous and arterial blood. L-NAME (an NO synthase inhibitor) or HOE-140 (a bradykinin receptor antagonist) attenuated (P<0.05) the increase in CBF (29+/-3 and 35+/-2 mL. 100 g(-1). min(-1), n=5 each), FS (4.8+/-0.6% and 6.9+/-1.7%, n=5 each), LER (-47+/-8% and -35+/-9%, n=5 each), and nitrate+nitrite (3+/-2 and 8+/-4 nmol/mL, n=5 each) due to nifedipine infusion. CONCLUSIONS: These results indicate that the calcium channel blocker nifedipine mediates coronary vasodilation and improves myocardial ischemia through both bradykinin/NO-dependent and -independent mechanisms.

Animals↗

PubMed2000

Relation of transesophageal echocardiographic findings to subtypes of cerebral infarction in patients with atrial fibrillation.

BACKGROUND: Transesophageal echocardiography (TEE) has been used to identify the potential risk for cardiogenic embolism in patients with atrial fibrillation (AF). However, ischemic stroke in patients with AF is not always attributable to embolism. Identification of the risk of embolic versus atherothrombotic stroke should lead to the optimal individualized management of patients with AF. HYPOTHESIS: The goal of the study was to determine the relation between cortical infarction and perforating infarction and TEE findings in patients with AF. METHODS: We investigated the clinical usefulness of TEE in the risk stratification of clinical subtyping of the cerebral infarctions which were divided into two territories of the cortical branch (cortical infarction due to embolism) and deep perforators (perforating infarction due to atherothrombosis). Left atrial spontaneous echo contrast, peak flow velocity in the left atrial appendage, and generalized atherosclerosis as estimated by the intima-media wall thickness of the thoracic aorta were assessed by TEE in 118 consecutive patients with either paroxysmal (n = 44) or chronic (n = 74) AF. All patients underwent either brain computed tomography or magnetic resonance imaging. RESULTS: Cortical and perforating infarction was found in 39 and 18% of patients, respectively. The grade of spontaneous echo contrast was higher in patients with than in those without cortical infarction (p < 0.05). In contrast, patients with perforating infarction showed significant increase in the aortic wall thickness when compared with patients without perforating infarction (p < 0.05). In addition, multivariate logistic analysis revealed that spontaneous echo contrast was an independent predictor of cortical infarction, while intima-media wall thickness of the aorta, hypertension, and age were useful in predicting the risk of perforating infarction. CONCLUSIONS: Transesophageal echocardiography has a potential role in the risk stratification for cortical and perforating infarction in patients with AF.

Aged↗

PubMed2000

Correlation between high-resolution computed tomographic, magnetic resonance and pathological findings in cases with non-cancerous but suspicious lung nodules.

Computed tomography scans, including thin-section high-resolution computed tomography (HRCT), occasionally fail to differentiate between small non-cancerous nodules from lung cancers. We describe nine such lesions ( < 20 mm in diameter) initially identified through our screening program for lung cancer using CT scanning. Pathological diagnoses included nodular fibrosis (n = 4), granuloma (n = 1), cryptococcoma (n = 1), localised organising pneumonia (n = 1), inflammatory pseudo-tumour (n = 1) and sclerosing haemangioma (n = 1). High-resolution CT findings, together with MRI findings with contrast-enhanced dynamic studies, were retrospectively evaluated. Additional cases should be identified and radiologically characterised in order to reduce the number of non-cancerous tumours that are treated by unnecessary surgery.

Aged↗

PubMed2000

Ectopic expression of telencephalin in brains with holoprosencephaly.

Telencephalin (TLN), a telencephalon-specific glycoprotein, is exclusively expressed in neurons of the mammalian telencephalon. In the normally developing human brain, TLN immunoreactivity appeared and increased from 35 gestational weeks (GW) in the temporal cortex, and reached adult level at 5 months of postnatal age, being strong in the molecular layer, and weak in the external and internal granular layers. TLN expression corresponded with the development of neuronal dendrites and synapses. In brains with holoprosencephaly TLN immunoreactivity was already strong from as early as 28 GW. Staining was weak in the molecular layer, but strong in the external sparse and middle cellular layers in most cases. Notably, TLN was abundant in the glomerular structures in the internal pyramidal and multiform layers of fetal brains with alobar holoprosencephaly, which disappeared with increasing age. These results indicate premature and ectopic development of the dendrites and synaptic network in holoprosencephaly.

Adolescent↗

PubMed2000

Developmental expression of myotonic dystrophy protein kinase in brain and its relevance to clinical phenotype.

To investigate the pathophysiologic role of myotonic dystrophy protein kinase (DMPK) in the brain in myotonic dystrophy (MD), the developmental characteristics of DMPK immunoreactivity in the central nervous system and its alteration with disease were studied. Eleven patients' brain with MD (5 congenital form, 6 adult form) were examined by immunohistochemistry using a specific antibody against synthetic DMPK peptides, antipeptide DM1, and compared with 30 control brains, including 16 age-matched controls. In controls, DM1-immunoreactive neurons appeared in the early fetal frontal cortex and cerebellar granule cell layer, persisting through 29 weeks of gestation and then disappearing. In contrast, immunoreactive neurons continued to persist in the cerebral cortex and cerebellar granule cell layer of MD patients. When we counted DM1-immunoreactive neurons, the increase over controls was greater in the congenital form of MD than in the adult form, and was greater in the cerebrum than in the cerebellum in both forms of MD. DM1 immunostaining was predominantly nuclear, mirroring Western blotting of subcellular fractions. Differences in DM1 expression related to development and to the two forms of MD may be closely related to the pathogenesis of mental retardation in this disease.

Adult↗

PubMed2000

The developmental and aging changes of Down's syndrome cell adhesion molecule expression in normal and Down's syndrome brains.

We studied the expression of Down's syndrome cell adhesion molecule (DSCAM) in Down's syndrome (DS) and control brains, using antisera against peptide fragments of DSCAM. On Western blots of human, mouse and rat brain homogenates, the antisera recognized a product at approximately 200 kDa. In the brain of a 2-year-old patient with DS, Western blotting revealed an overexpression of DSCAM compared to an age-matched control. Immunohistochemistry demonstrated DSCAM in the cerebral and cerebellar white matter of both control and DS subjects, in accordance with the temporal and spatial sequence of myelination. In DS brains, immunoreactivity for DSCAM, compared to that for controls, was enhanced in the Purkinje cells at all ages, and in the cortical neurons during adulthood. In demented DS patients, DSCAM immunoreactivity was observed in the core and periphery of senile plaques. The pattern of DSCAM expression suggests that it may play a role as an adhesion molecule regulating myelination. The overexpression of DSCAM may also play a role in the mental retardation and the precocious dementia of DS patients, although the mechanism of neuronal dysfunction is undetermined.

Adolescent↗

PubMed2000

Simultaneous loss of hamartin and tuberin from the cerebrum, kidney and heart with tuberous sclerosis.

Tuberous sclerosis (TSC) is caused by a mutation in either the TSC1 or TSC2 gene. The clinical manifestations of mutations of the two genes are hardly distinguishable, for reasons as yet unknown. In this study, we examined the expression of the products of these genes, hamartin and tuberin, in control and TSC tissues. Western blotting disclosed that hamartin and tuberin are both abundant in the cerebral gray matter and that they have similar subcellular distributions and developmental patterns of expression. Immunohistochemical localizations of hamartin and tuberin were also similar, with high levels of expression being localized to the cerebral neurons and glial cells, renal uriniferous and collecting tubules, and cardiac muscles. In the cerebrum with TSC, both hamartin and tuberin were simultaneously reduced in the cortical tubers and subependymal giant cell astrocytomas, and from the normal-appearing cortex. The renal angiomyolipomas and cardiac rhabdomyomas also showed a loss of both the proteins. These results provide evidence for the co-localization and interaction of hamartin and tuberin in vivo, and suggest that a mutation in one TSC gene may secondarily affect the expression of the other in some TSC lesions.

Adolescent↗

PubMed2000

Association of osteopontin with ischemic axonal death in periventricular leukomalacia.

Osteopontin (OPN) is a bone matrix protein expressed my macrophages and related to the process of tissue calcification, and is also known to protect ischemic cells. To understand how OPN is involved in the process of ischemic axonal death in periventricular leukomalacia (PVL), we examined the immunoreactivity of OPN and ionized calcium binding adaptor molecule 1 (Iba1; microglia/macrophage marker) at various stages of PVL. OPN immunoreactivity paralleled the number of Iba1-positive foam cells; a finding which suggests the production of OPN protein by foam cells. OPN immunoreactivity was not found in either normal white matter or acute PVL lesions, but was detected at the subacute and chronic stages in swollen and calcified axons bordering the ischemic zone. These findings suggest that OPN is closely associated with death of swollen axons at the periphery of the ischemic zone, regulating the presence or absence of calcification.

Axons↗

PubMed2000

A novel migration-related gene product, doublecortin, in neuronal migration disorder of fetuses and infants with Zellweger syndrome.

Immunohistochemical expression of doublecortin (DCX), KIAA0369 (KIA) and LIS1 proteins as well as nestin and vimentin in the cerebral cortices of six patients with Zellweger syndrome (ZS), aged 19 gestational weeks (GW) to 8 months, was compared with that in nine controls, aged 12 GW to 8 months. DCX immunoreactivity was apparently reduced in ZS, particularly in the cortical plate of fetuses, and in the subependymal foci of heterotopic neurons of the infants. Reduced expression of DCX in ZS was confirmed by Western blot analysis. On the other hand, neuronal expression of nestin was high in the cortical plate, migrating cells of the white matter and germinal cells in the ventricular zone in fetuses with ZS. Immunoreactivities for KIA, LIS1 and vimentin in ZS were comparable to those of controls. Reduced expression of DCX may be responsible for the neuronal migration disorder, and increased expression of nestin may be another evidence for delayed neuronal maturation in ZS.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗

PubMed2000

Short-term inhaled nitric oxide in canine lung transplantation from non-heart-beating donor.

BACKGROUND: Use of lungs harvested from non-heart-beating donors (NHBDs) would increase the pulmonary donor pool; however, this strategy would have higher risk of early postoperative graft dysfunction due to unavoidable warm ischemic time. We evaluated the effects of short-term inhaled nitric oxide (NO) during reperfusion in canine left single-lung allotransplantation from a non-heart-beating donor. METHODS: The donor dogs were sacrificed without heparinization and left at room temperature for 3 hours. Then, recipient dogs received a left single-lung allotransplantation. After implantation, the right bronchus and pulmonary artery were ligated. In group 1 (n = 6), NO gas was administered continuously at a concentration of 40 parts per million throughout a 6-hour assessment period. In group 2 (n = 6), NO gas was administered for the initial 1 hour during reperfusion. In group 3 (n = 6), nitrogen gas was administered for control. RESULTS: Groups treated with NO exhibited lower pulmonary vascular resistance, as well as improved survival and oxygenation. There was no significant difference in these parameters between group 1 and group 2. Myeloperoxidase activity was significantly lower in NO-treated groups. CONCLUSIONS: Inhaled NO during reperfusion is beneficial in lung transplantation from non-heart beating donors. The beneficial effect is obtained mainly during the first hour of reperfusion.

Administration, Inhalation↗

PubMed2000

Pulmonary function after lobectomy: video-assisted thoracic surgery versus thoracotomy.

BACKGROUND: Whether video-assisted thoracic surgery (VATS) improves postoperative pulmonary function is still controversial. We compared postoperative pulmonary function after VATS lobectomy and standard lobectomy. METHODS: Eleven patients who had undergone standard lobectomy and 10 patients who had undergone VATS lobectomy were studied. Arterial blood gas analyses were performed on the 4th, 7th, and 14th postoperative days. Pulmonary function, including forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1.0), and peak flow rate (PFR) were measured on the 7th and 14th postoperative days (early phase), and approximately 1 year after surgery (late phase). RESULTS: Pulmonary function, as assessed with arterial oxygen partial pressure (PaO2) (p = 0.054), arterial oxygen saturation (O2SAT) (p = 0.063), FVC (p = 0.10), and FEV1.0 (p = 0.08), was better after VATS lobectomy than after thoracotomy on the 7th postoperative day. PFR was significantly better after VATS on both the 7th and 14th postoperative days (p = 0.008 and p = 0.03, respectively). CONCLUSIONS: VATS lobectomy had advantages on early postoperative pulmonary function. We conclude that VATS lobectomy is a beneficial alternative to standard thoracotomy, especially for patients with poor pulmonary reserve.

Aged↗