Biomedical subjects

S Takashima

Publications and source records attributed to S Takashima.

At least 181 records · Page 10Linked to original sources

PubMed1999

Molecular cloning and functional expression of two members of mouse NeuAcalpha2,3Galbeta1,3GalNAc GalNAcalpha2,6-sialyltransferase family, ST6GalNAc III and IV.

Two cDNA clones encoding NeuAcalpha2,3Galbeta1,3GalNAc GalNAcalpha2, 6-sialyltransferase have been isolated from mouse brain cDNA libraries. One of the cDNA clones is a homologue of previously reported rat ST6GalNAc III according to the amino acid sequence identity (94.4%) and the substrate specificity of the expressed recombinant enzyme, while the other cDNA clone includes an open reading frame coding for 302 amino acids. The deduced amino acid sequence is not identical to those of other cloned mouse sialyltransferases, although it shows the highest sequence similarity with mouse ST6GalNAc III (43.0%). The expressed soluble recombinant enzyme exhibited activity toward NeuAcalpha2, 3Galbeta1, 3GalNAc, fetuin, and GM1b, while no significant activity was detected toward Galbeta1,3GalNAc or asialofetuin, or the other glycoprotein substrates tested. The sialidase sensitivity of the 14C-sialylated residue of fetuin, which was sialylated by this enzyme with CMP-[14C]NeuAc, was the same as that of ST6GalNAc III. These results indicate that the expressed enzyme is a new type of GalNAcalpha2,6-sialyltransferase, which requires sialic acid residues linked to Galbeta1,3GalNAc residues for its activity; therefore, we designated it mouse ST6GalNAc IV. Although the substrate specificity of this enzyme is similar to that of ST6GalNAc III, ST6GalNAc IV prefers O-glycans to glycolipids. Glycolipids, however, are better substrates for ST6GalNAc III.

Amino Acid Sequence↗

PubMed1999

The apparently symmetrical hexagonal bilayer hemoglobin from Lumbricus terrestris has a large dipole moment.

The giant approximately 3.6 MDa hexagonal bilayer hemoglobin (HBL Hb) from Lumbricus terrestris consists of 12 213-kDa dodecamers of four globin chains ([b + a + c]3[d]3) tethered to a central scaffold of approximately 36 non-globin, linker subunits L1-L4 (24-32 kDa). Three-dimensional reconstructions obtained by electron cryomicroscopy showed it to have a D6 point-group symmetry, with the two layers rotated approximately 16 degrees relative to each other. Measurement of the dielectric constants of the Hb and the dodecamer over the frequency range 5-100 kHz indicated relaxation frequencies occurring at 20-40 and 300 kHz, respectively, substantially lower than the 700-800 kHz in HbA. The dipole moments calculated using Oncley's equation were 17,300 +/- 2300 D and 1400 D for the Hb and dodecamer, respectively. The approximately threefold higher dipole moment of the dodecamer relative to HbA is consistent with an asymmetric shape in solution suggested by small-angle X-ray scattering. Although a two-term Debye equation and a prolate ellipsoid of revolution model provided a good fit to the experimental dielectric dispersion of the dodecamer, a three-term Debye equation based on an oblate ellipsoid of revolution model was required to fit the asymmetric dielectric dispersion curve of the Hb: the required additional term may represent either an induced dipole moment or a substructure which rotates independently of the main permanent dipole component of the Hb. The D6 point-group symmetry implies that the dipole moments of the dodecamers cancel out. Thus, in addition to a possible contribution from fluctuations of the proton distribution, the large dipole moment of the Hb may be due to an asymmetric distribution of the heterogeneous linker subunits.

Animals↗

PubMed1999

Comparison of gene structures and enzymatic properties between two endoglucanases from Humicola grisea.

We have cloned two endoglucanase genes (egl3 and egl4) from a thermophilic fungus, Humicola grisea. The coding region of the egl3 gene was interrupted by an intron of 56-bp, and the deduced amino acid sequence of the egl3 gene was 305 amino acids in length and showed 98.4% identity with Humicola insolens EGV. The coding region of the egl4 gene was also interrupted by an intron of 173-bp, which contains 34 TTC repeated sequence units, and the deduced amino acid sequence of the egl4 gene was 227 amino acids in length and showed 61.5% identity with H. grisea EGL3. The typical hinge and the cellulose-binding domain were observed in the C-terminal region of EGL3, but they were not observed in EGL4. In the 5' upstream region of both genes, there were a TATA box or its similar sequence, CAAT motifs, and 6-bp sites which are identical or similar to the consensus sequence for binding a catabolite repressor CREA in Aspergillus nidulans. The egl3 and the egl4 genes were expressed in Aspergillus oryzae, and the translation products were purified. The fusion protein, EGL4CBD, which consists of a catalytic domain of EGL4 and the C-terminal region of EGL3, was also constructed and produced by A. oryzae, and purified. These enzymes showed relatively high activity toward carboxymethyl cellulose (CMC) and could not hydrolyze p-nitrophenyl-beta-D-glucoside and p-nitrophenyl-beta-D-cellobioside. The positive effect of substituting the C-terminal region of EGL4 with that of EGL3 was observed in the hydrolysis of CMC.

Amino Acid Sequence↗

PubMed1999

Detection of medullary thyroid carcinoma and regional lymph node metastases by magnetic resonance imaging.

OBJECTIVES: To evaluate the usefulness of magnetic resonance imaging in detecting primary medullary thyroid carcinoma (MTC) and regional metastasis to the lymph nodes, and to correlate magnetic resonance signal intensity to pathologic changes. MATERIALS AND METHODS: Magnetic resonance images in 14 patients with MTC (9 with primary disease, 5 with recurrent disease) were reviewed for signal intensities, tumor morphologic characteristics, and tumor invasion with spin-echo T1-weighted images (T1WIs), T2-weighted images (T2WIs), and gadolinium-enhanced T1WIs. Multiple regression analysis was used to examine the correlation between T2-weighted signal intensity and pathologic findings. Lymph nodes were evaluated based on signal and morphologic characteristics. RESULTS: Magnetic resonance imaging detected tumors in 9 (90%) of the 10 patients who had MTC in the thyroid gland. Extrathyroidal spread of the tumors was correctly predicted using this procedure. Most tumors were hyperintense or markedly hyperintense on T2WI. T2-weighted signal intensity of the tumor was associated with increased amyloid deposition and high tumor cellularity and low level of fibrosis (r = 0.91, P = .01). Lymph node metastasis was present in 38 (23%) of 168 surgically dissected nodes. The combined use of 4 criteria (nodule size, a minimum-maximum diameter ratio of 0.80 or greater, marked hyperintensity on T2WI, and necrosis in the node) yielded a high detection accuracy (93%) for nodal metastasis, with 74% sensitivity and 98% specificity. CONCLUSIONS: Magnetic resonance imaging is useful for detecting primary and recurrent MTC, and its signal intensity reflects the underlying pathologic changes.

Adult↗

PubMed1999

Parotid gland lesions: diagnosis of malignancy with MRI and flow cytometric DNA analysis and cytology in fine-needle aspiration biopsy.

BACKGROUND: The purpose of this study was to assess the capability of magnetic resonance imaging (MRI) and cytology and flow cytometric (FCM) deoxyribonucleic acid (DNA) analysis in fine-needle aspiration biopsy (FNAB)-derived materials for diagnosing malignancy of the parotid lesions and the efficacy of FCM analysis in FNAB. METHODS: Magnetic resonance imaging findings and FCM results (ploidy and S + G2 + M phases [S + G2M] fraction) and cytology in FNAB-derived materials in 26 patients with 26 parotid lesions (12 benign lesions, 14 malignancies) were assessed for predicting malignancy. Flow cytometric results in aspirates were compared with those in surgically resected tissues. RESULTS: When a single predictor was used, cytology (92% accuracy) was most accurate for malignancy, followed by ill-defined margin (88% accuracy) and aneuploidy (88% accuracy). The combination of FCM and cytology raised the rate of sufficient materials from 92% to 100% and accuracy from 92% to 96% compared with cytology alone. The same highest accuracy (96%) was obtained with the combination of the ill-defined margin or other findings such as cytology, aneuploidy, or a high (S + G2M) fraction (6% <). Deoxyribonucleic acid ploidy in the FNAB showed full agreement with that in the surgical specimens. Receiver operating characteristic curves showed that the diagnosis of malignancy with (S + G2M) fraction in FNAB was superior to that in surgical specimens, but no significant difference was noted. CONCLUSIONS: A combination of MRI findings, cytology, and FCM results is optimal for diagnosing malignancies of the parotid lesions, and FNAB may replace the surgical specimens in FCM analysis.

Adolescent↗

PubMed1999

Lymphatic routes of the stomach demonstrated by gastric carcinomas with solitary lymph node metastasis.

To clarify whether or not the lymphatic routes that have long been generally accepted are indeed correct, we retrospectively examined the clinical records of patients with solitary lymph node metastasis from gastric carcinoma. From 735 patients gastrectomized with lymph node dissection (more than D1), 51 (7%) were histologically proven to have only one lymph node involved. In 44 of these 51 patients, the involved nodes were all in the perigastric region (N1). There were also 7 patients with a jumping metastasis to the N2-N3 nodes. Three of them were found along the left gastric artery (#7 according to Japanese classification) and the other 4 were found along either the common hepatic artery (#8) or the proper hepatic artery (#12). The depth of invasion was submucosal in 2, proper-muscular in 2, subserosal in 1, and serosa-exposed in 2, and the conclusive stage was II in 2, IIIa in 3, and IIIb in 2. However, 1 of these patients died of liver cirrhosis and 2 died of pneumonia, while the other 4 were still alive at the time of this report more than 5 years after surgery. These results suggest that not every sentinel node is located in the perigastric region near the primary tumor and that, if the preoperative examination indicates submucosal invasion, then a systematic regional lymph node dissection should therefore be carried out.

Carcinoma↗

PubMed1999

Gastric cancer with sarcoid reactions in the regional lymph nodes, the stomach wall, and the splenic parenchyma: report of a case.

A 66-year-old man was referred to our institute for investigation of heartburn and epigastralgia. Endoscopic examination demonstrated a type 4' gastric cancer which occupied the whole stomach. At laparotomy, multiple small nodules were found in the spleen which were diagnosed as metastases of the gastric cancer. Thus, total gastrectomy with distal pancreatectomy, splenectomy, cholecystectomy, and left adrenalectomy, combined with D4 lymph node dissection, was performed. Microscopic examination of the tumor revealed tubular and mucinous adenocarcinoma which invaded the muscularis propria. Sarcoid reactions were observed in the submucosa adjacent to the carcinoma tissue. Only one lymph node from station no. 8a demonstrated tumor metastasis, while those from station nos. 1, 2, 7, 8, 9, 10, 11, 13, and 16 revealed sarcoid reactions without tumor metastases. Subsequently, the multiple small nodules that had been presumed to be splenic metastases at laparotomy were found to be sarcoid reactions similar to those seen in the submucosa and regional lymph nodes. Since no skin or ocular lesions indicative of systemic sarcoidosis were seen in this patient, a diagnosis of advanced gastric cancer associated with sarcoid reactions was established. To our knowledge, there have been no previous reports regarding an association between sarcoid reactions in the spleen and gastric cancer.

Adenocarcinoma, Mucinous↗

PubMed1999

Port site recurrence of unexpected gallbladder carcinoma after a laparoscopic cholecystectomy: report of a case.

Unexpected gallbladder carcinoma was identified in a 71-year-old woman after she underwent a laparoscopic cholecystectomy (LC) for symptomatic cholelithiasis. A subsequent laparotomy for a resection of the liver bed and a dissection of the lymph nodes around the hepatoduodenal ligament was done. Two and a half years later, the patient developed subcutaneous metastasis at the epigastric trocar site through which the gallbladder was removed. A third operation was thus performed, revealing no evidence of peritoneal dissemination, liver metastasis, or lymph node metastasis, and the abdominal wall mass was resected. The histological findings confirmed the diagnosis of metastatic carcinoma of the gallbladder. We recommend that when planning LC, the possibility of malignancy should thus be kept in mind. However, if there is any sign which does not completely exclude malignancy, such as a contracture or wall thickness of the gallbladder, LC should be performed by the abdominal wall lifting method and using a protective bag for the removal of the gallbladder.

Abdominal Muscles↗

PubMed1999

Small peripheral carcinomas of the lung: thin-section CT and pathologic correlation.

The aim of this study was to clarify the thin-section CT features of small peripheral carcinomas of the lung on the basis of pathologic findings of tumor growth patterns. Thin-section CT and pathologic correlation was evaluated in 19 patients with surgically verified small peripheral carcinomas of the lung ( < 20 mm in size) that had been detected in a screening trial for lung cancer using spiral CT. Four thin-section CT types of nodules were observed: (a) type L1 (4 of 19, 21 %), a fairly well-defined nodule with ground-glass attenuation, corresponding to tumor lepidic growth without alveolar collapse; (b) type L2 (4 of 19, 21 %), a partly lobulated nodule with a low but inhomogeneous attenuation, corresponding to tumor lepidic growth with scattered foci of alveolar collapse; (c) type L3 (4 of 19, 21 %), an ill-defined nodule with an irregularly shaped higher-density central zone in a ground-glass attenuation peripheral zone, accompanied by convergence of the bronchovascular structures from the surrounding lung parenchyma, which corresponded to desmoplastic response in the central zone and to tumor lepidic growth in the peripheral zone; and (d) type H (7 of 19, 37 %), a well-defined nodule with a solid homogeneous attenuation, corresponding to tumor hilic growth. Thin-section CT features of small peripheral carcinomas of the lung can be classified into four types, based on the density distribution of the tumor, which reflect the histologic findings.

Adenocarcinoma↗

PubMed1999

The up-regulation of metabotropic glutamate receptor 5 (mGluR5) in Down's syndrome brains.

We investigated the expression of metabotropic glutamate receptor 5 (mGluR5), a subtype of group I mGluRs, in the cerebral cortex of cases with Down's syndrome (DS), using immunohistochemistry and immunoblotting with this receptor. The up-regulation of mGluR5 was observed in DS by immunohistochemistry, and atrophic pyramidal neurons were immunolabelled in elderly DS cases. Western blotting confirmed the increased expression in DS brains. Since group I mGluR regulates the metabolism of amyloid precursor protein (APP) and accelerates its processing into non-amyloidogenic APP, the overexpression of mGluR5 may be related to the pathological state of APP metabolism in DS.

Adolescent↗

PubMed1999

Granulocyte-colony-stimulating-factor-producing hepatocellular carcinoma.

Patients with hepatocellular carcinoma (HCC) rarely show marked granulocytosis. We report an interesting case of rapidly growing poorly differentiated HCC associated with marked granulocytosis. The blood leukocyte count decreased following several treatments for HCC, including transcatheter arterial embolization, and increased again along with tumor regrowth. The serum levels of granulocyte colony-stimulating factor (G-CSF) were markedly elevated, and immunohistochemical study showed G-CSF staining in the cytoplasm of certain HCC cells. These findings confirm that HCC in this case was a G-CSF-producing tumor.

Aged↗

PubMed1999

Increased cerebrospinal fluid levels of substance P in patients with amyotrophic lateral sclerosis. Short communication.

To clarify the mechanism of brain and spinal cord impairment in amyotrophic lateral sclerosis (ALS), we measured the cerebrospinal fluid (CSF) levels of substance P (SP) in 11 patients with sporadic ALS. Findings were compared with those obtained in controls and diseased controls. The CSF SP levels of patients with ALS, and particularly in patients with a disease duration of less than 2.5 years, were significantly higher than those in controls. These findings strongly suggested that SP may play an important role in the pathophysiology of ALS.

Adult↗

PubMed1999

Prenatal diagnosis of peroxisomal D-3-hydroxyacyl-CoA dehydratase/D-3-hydroxyacyl-CoA dehydrogenase bifunctional protein deficiency.

The prenatal diagnosis of peroxisomal D-3-hydroxyacyl-coenzyme A (CoA) dehydratase/D-3-hydroxyacyl-CoA dehydrogenase bifunctional protein (D-BP) deficiency was performed by peroxisomal beta-oxidation assay, indirect immunofluorescence staining, immunoblot analysis, and gene analysis of cultured amniocytes obtained from a fetus at 16 weeks' gestational age. beta-Oxidation activity, measured by [1-14C] lignoceric acid oxidation, was markedly decreased compared with the controls. Large peroxisomes were readily identified by immunofluorescence staining with anti-human catalase, as was found in the reported patients. Immunoreactive D-BP material was absent on immunoblot analysis and immunofluorescence staining with anti-human D-BP. Reverse transcriptase polymerase chain reaction (RT-PCR) analysis revealed the presence of the same 237-bp deletion in the cDNA as that detected in a sibling (the proband). The autopsied fetus showed the characteristic facial appearance and D-BP was deficient on immunoblot and immunohistopathological studies of the fetal tissues. No neuronal migration disorder was identified. This seems to be the first prenatal diagnosis of D-BP deficiency.

17-Hydroxysteroid Dehydrogenases↗

PubMed1999

High expression of doublecortin and KIAA0369 protein in fetal brain suggests their specific role in neuronal migration.

The X-linked subcortical laminar heterotopia and lissencephaly syndrome is a disorder of neuronal migration caused by a mutation in XLIS, a recently cloned gene on chromosome Xq22.3-q23. The predicted protein product for XLIS, doublecortin (DC), shows high homology to a putative calcium calmodulin-dependent kinase, KIAA0369 protein (KI). Here we identified DC and KI in the brains of human and rat fetuses by immunochemical and immunohistochemical means. In this study, Western blotting demonstrated that both DC and KI are specific to the nervous system and are abundant during the fetal period, around 20 gestational weeks in humans and embryonic days 17 to 20 in rats. Immunostaining of the developing neocortex disclosed localization of DC and KI immunoreactivities in neuronal cell bodies and processes in the zones of ongoing neuronal migration. Although KI showed a somewhat wider distribution than DC, the temporal and spatial patterns of their expression were similar. These results suggest that DC and KI participate in a common signaling pathway regulating neuronal migration.

Animals↗

PubMed1999

Developmental expression of monocyte chemoattractant protein-1 in the human cerebellum and brainstem.

The developmental expression of monocyte chemoattractant protein-1 (MCP-1) in the cerebellum, medulla oblongata and pons was investigated in 26 normal human brains, ranging from 20 weeks of gestation (GW) to adulthood by means of an immunohistochemical method. Immunoreactivity to MCP-1 was observed in neurons of the cerebellum and brainstem, and was mainly distributed in the cytoplasm and dendrites. MCP-1-positive Purkinje cells appeared at 27 GW, reached a peak at 36 GW, and then decreased after 1 month of age, almost completely disappearing by 1-2 years of age. MCP-1-reactive neurons in the dentate nucleus and inferior olivary nucleus showed temporal increases similar to that of Purkinje cells. In the pons, however, MCP-1 reactivity was low in neurons of the pontine nuclei persisting from the fetal to the adult period, and was very low and short in the reticular formation and cranial nerve nuclei during the fetal and/or neonatal period. MCP-1 Western blotting of the cerebellar cortex confirmed the specificity of the immunohistochemistry. Our results suggest that MCP-1 may be related to the maturation of Purkinje cells, the dentate nucleus, the inferior olivary nucleus, and their network, promoting the growth of dendrites and synapses. Furthermore, MCP-1 may also be useful for the study of abnormal neuron development and ischemic damage.

Adolescent↗

PubMed1999

Early axonal and glial pathology in fetal sheep brains with leukomalacia induced by repeated umbilical cord occlusion.

We conducted a chronic preparation experiment involving near term fetal sheep to evaluate the contribution of umbilical cord occlusion to fetal brain injury. In experimental groups (n = 11), complete cord occlusion for 3 min followed by 5 min release, repeated 5 times were performed at 3 days after initial surgery. Instrumental cases without cord occlusion (n = 3) and uninstrumental twins (n = 6) were also examined as controls. Multiple necrotic foci predominantly in the periventricular white matter were found in the fetal brains examined at 1-3 days after cord occlusion. To estimate the contribution of early axonal and glial reaction to brain injury the following immunohistochemical study was performed. In the lesions, coagulation necrosis, axonal swelling and microglial activation were demonstrated with amyloid precursor protein or ionized calcium binding adapter molecule 1 immunohistochemistry. The induction of tumor necrosis factor alpha and inducible nitric oxide synthase were also detected immunohistochemically in the microglia at 1 and 3 days after cord occlusion. In contrast, the reaction of glial fibrillary acidic protein positive astrocytes was faint at 1 day after occlusion, but the induction of cyclooxygenase-2 was observed. These findings suggest the glial reaction of cytokines and free radicals induced by fetal hypoxia may contribute to the occurrence of brain injury.

Amyloid beta-Protein Precursor↗

PubMed1999

Effects of nitric oxide synthase inhibition on the cerebral circulation and brain damage during kainic acid-induced seizures in newborn rabbits.

The nitric oxide (NO) synthase inhibitor, N-omega-nitro-L-arginine methyl ester (L-NAME), was used to investigate the effect of endogenous NO on the cerebral circulation and brain damage during kainic acid (KA)-induced seizures in newborn rabbits. The cerebral blood flow (CBF), by laser doppler flowmetry, cerebral oxygenation (concentrations of oxy-(HbO2), deoxy-(HbR) and total hemoglobin (tHb) in brain tissue), by near-infrared spectroscopy (NIRS), mean arterial blood pressure (MABP), electroencephalography (EEG), and hippocampal neuronal damage were evaluated. Pretreatment with L-NAME caused significant decreases in CBF, HbO2, and tHb, and a significant increase in HbR during KA-induced seizures, compared with pretreatment with saline (P < 0.05), without a significant difference in MABP. Our study also demonstrated that pretreatment with L-NAME reduced the seizure activity and neuronal cell death in the hippocampus elicited by the systemic administration of KA in the neonatal brain. These results suggest that NO is of major importance in the neurodestructive process in spite of its roles in maintaining both the CBF and cerebral oxygenation during KA-induced seizures in the neonatal brain.

Animals↗

PubMed1999

Expression of protective protein in human tissue.

The authors investigated by immunohistochemistry the distribution of protective protein in human tissues. Immunoreactivity was observed in the cytoplasm, revealing a granular pattern and cell type specificity. The most intense staining was observed in the large neurons of brain, distal and collecting tubular cells of kidney, epithelial cells of bronchus, and Leydig cells of testis. In a patient with galactosialidosis type IIa, all these stains were absent. The neurons that were most strongly stained in the control group, such as the Betz cells, neurons in the basal forebrain, motor neurons in the cranial nerve nuclei, and ventral horn cells of the spinal cord, were markedly ballooned in the patient with galactosialidosis.

Adolescent↗