[Prolyl oligopeptidase family: a new serine protease family distributed in endo- and exo-peptidases].
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Amino Acid Sequence↗
Biomedical subjects
T Yoshimoto
Publications and source records attributed to T Yoshimoto.
[Effect of free radicals on the permeability of the blood brain barrier--using in vitro blood brain barrier model of human-SOD transgenic mouse].
Free radicals have been implicated in pathogenesis of vasogenic edema caused by post-ischemic reperfusion injury. It has been reported that Cu-Zn superoxide dismutase transgenic mouse (tg-mouse) which is overexpressing Cu-Zn SOD, prevents post ischemic brain edema and decreases infarct size in middle cerebral artery occlusion model. To investigate the effects of free radicals and free radical scavengers on the permeability of the blood-brain barrier (BBB), we established in vitro BBB model, using cultured brain endothelial cells (BECs) which were extracted from the tg-mice and non tg-mice (control). To make the BBB model, the BECs were cultured on the membrane which has 0.45 micron pores. After cells became confluent, the electrical resistance across the cell monolayer, which reflects the para-cellular flux of ionic molecules, was measured. The BBB model of the tg-mouse were incubated with menadione (Vitamin K3, intracellular O2- producting agent), and the segmental changes of the electrical resistance through the monolayer were compared with those of the control. Moreover, to investigate the effect of the ironic ions which influence the metabolism of free radicals, desferroxamine mesylate (Fe chelating agent) was added to the BBB models before menadione treatment. The cultured brain endothelial cells of tg-mouse has 1.7 times higher SOD activity than that of the control. In the menadione treatment, it showed a significant decrease of electrical resistance in the tg-mouse earlier than that of the control.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
[Whole head measurement of auditory evoked magnetic field using a MR-linked helmet shaped MEG system].
Authors compared MR anatomy and magneto-encephalographic (MEG) functional methods in locating auditory cortex in 20 normal volunteers and 56 patients with intracranial structural lesions. Auditory evoked response was measured over the entire head, using a helmet shaped 64 channel MEG system. In each subject, three dimensional MR image was obtained with identical coordinate system of MEG. Best fit sphere to each subject's head was calculated from MRI data. Signal source of auditory evoked MEG was estimated using a two dipole model in the best fit sphere. Position and orientation of dipoles were superimposed on each subject's MRI. Both left and right dipolar patterns appeared about 100 ms after unilateral auditory stimuli (N100m) in 19 normal subjects and 47 patients. These dipolar patterns overlap each other across the midline. A two dipole model successfully localized bilateral N100m dipoles in the upper surface of superior temporal planes. N100m response was missing unilaterally in 1 normal subjects and 9 patients inspite of normal audiometry findings, suggesting sub-clinical auditory dysfunction. The MR-linked whole head MEG is a non-invasive tool to localize source of auditory evoked N100m response even in the case with intracranial structural lesions.
Acoustic Stimulation↗
[CA 19-9 producing lung tumors].
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Animals↗
Multilobulated cystic formation in the brain stem with Benedikt's syndrome: case report.
A 26-year-old man presented with an unusual multilobulated cystic formation in the brain stem with normal pressure hydrocephalus, followed by fluctuating cyst volume and Benedikt's syndrome. Ventriculoperitoneal shunting to relieve the hydrocephalus caused an increased cystic size, resulting in worsened neurological deficits. Cystectomy and an additional shunt resolved the symptoms. Immunohistochemical and electron microscopic examinations of the surgical specimen revealed no epithelial lining but numerous astrocytic processes on the luminal surface, probably resulting from expansion of the cyst. This case suggests that cystectomy before shunt emplacement is recommended in similar cases.
Adult↗
[Follow-up study of malignant astrocytomas showing complete response after initial treatment].
The prognosis for patients with malignant astrocytomas is still poor. The identification of groups of patients with good prognostic factors should be helpful in selecting the treatment strategies. In general, important prognostic factors are thought to be the extent of surgical resection required, age, performance status, duration of symptoms, location, and pathological tumor grade. The purpose of this present study is to evaluate the prognosis of patients with complete response (CR), that is, complete disappearance of the tumor mass in the contrast enhancement of computerized tomography (CT) scan after initial treatment. An additional purpose is to examine the effect of factors such as pathological tumor grade, location, age of patient, and the extent of surgical resection in achievement of CR. The subjects of the study were 81 patients with supratentorial malignant astrocytomas (45 males, 36 females) treated with surgical resection and radiochemotherapy in our division since 1980, and followed up for more than 5 years. There were 57 anaplastic astrocytomas (WHO grade III) and 24 glioblastomas (WHO grade IV). The extent of surgical resection and the response to the therapy were evaluated by CT scans. The Kaplan-Meier method was used in generating survival plots. Twenty-two cases (27%) showed CR at the end of the initial treatment, and the other 59 cases (73%) showed Non CR. Fifteen cases (26%) among 57 grade III patients and 7 cases (29%) among 24 grade IV patients showed CR. Tumor locations of CR cases were exclusively superficial with the exception of one case that involved deep structure. Average age of CR cases and Non CR cases were 34.4 and 49.7, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
Brain Neoplasms↗
[Locating the central sulcus using three dimensional image fusion system of helmet shaped whole head MEG and MRI].
We compared MR anatomy and magnetoencephalographic (MEG) functional methods in locating the central sulcus. In 20 normal volunteers and 58 patients with intracranial structural lesions, the short latency somatosensory evoked magnetic fields for median nerve and posterior tibial nerve stimuli were measured over the entire head, using a helmet shaped MEG system. The dipole positions estimated by a single current dipole model were projected onto the three dimensional MRI. In 94% of a total of 156 hemispheres, N20m dipole positions for median nerve stimuli coincided with the central sulcus defined by MR anatomical image only. For posterior tibial nerve stimuli, the P38m dipole positions were estimated as being near the medial end of the anatomical central sulcus. MRI and MEG are complementary in locating the central sulcus, even in cases of intracranial structural lesions.
Adolescent↗
[Neurophysiologic studies on patients with migration disorder].
Neurophysiologic studies on six patients (five lissencephaly and one schizencephaly) with migration disorder were performed in order to evaluate the CNS function by multimodality evoked potentials. All cases revealed abnormalities in SSEP, four cases lost components below P 3 or had low voltage of P 3 indicating brainstem dysfunction in the somatosensory pathway. Two cases lost component below N 1 indicating sensory cortical dysfunction. Three cases revealed ABR abnormalities including a low amplitude of wave V, and one case revealed a prolonged peak latency of wave I and a low amplitude of all components. Two cases revealed abnormalities of poor cortical components in SEP, two cases in VEP, and three cases in MLR. Five cases had normal findings in P-SEP and three cases in VEP. The result of this study demonstrates that patients with migration disorder are frequently associated with cortical, brainstem and peripheral dysfunctions and has heterogeneity in pathophysiology.
Brain↗
[Effect of calcitonin gene-related peptide and vasoactive intestinal polypeptide on delayed cerebral vasospasm studied after experimental subarachnoid hemorrhage in rabbits].
Calcitonin gene-related peptide (CGRP) and vasoactive intestinal polypeptide (VIP) are intrinsic vasodilatory substances contained in perivascular nerve fibers innervating large intracranial arteries. Effects of these substances on delayed cerebral vasospasm were examined using a rabbit model of experimental subarachnoid hemorrhage (SAH). Sixty-one anesthetized rabbits received intrathecal fresh arterial blood on day-1 and intrathecal administration of different doses of CGRP, VIP or distilled water on day-4. Prior to the treatment, caliber of the spastic basilar artery was 73.4 +/- 0.9% of pre-SAH values. Serial angiograms after treatment demonstrated that 10(-10)mol/kg of CGRP dilated the spastic artery to 117.1% of pre-SAH levels and that dilatory effect of CGRP continued up to 6 hours after treatment. VIP injection also brought arterial dilatation up to 114.9% of pre-SAH levels, although the duration of the effect was less than 3 hours. Intrathecal administration of CGRP or VIP showed no adverse effect on the systemic and neurological state of the animals. These results indicate that intrathecal CGRP and VIP have therapeutic potential in treating delayed cerebral vasospasm after subarachnoid hemorrhage. Further investigations are expected to extend the effect of CGRP and VIP.
Animals↗
[Idiopathic eosinophilic pleural effusion].
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Eosinophilia↗
Diphasic increase in thrombin-antithrombin III complex in blood from the internal jugular vein following severe head injury.
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Antithrombin III↗
Induction of arachidonate 12-lipoxygenase mRNA by epidermal growth factor in A431 cells.
12(S)-Hydroxyeicosatetraenoic acid is biosynthesized from arachidonic acid by the microsomal fraction of human epidermoid carcinoma A431 cells, and the microsomal 12-lipoxygenase activity is enhanced by about 2-fold by epidermal growth factor (EGF) with a 10-h lag period (Chang, W.C., Ning, C.C., Lin, M.T., and Huang, J.D. (1992) J. Biol. Chem. 267, 3657-3666). The microsomal 12-lipoxygenase in A431 cells was only 3% active with linoleic acid as compared with arachidonic acid. The enzyme was immunoprecipitated by a monoclonal antibody against human platelet 12-lipoxygenase but not by that against porcine leukocyte enzyme. A 3.1-kilobase mRNA was detected in A431 cells by Northern blot analyses using cDNA probe of human platelet 12-lipoxygenase. EGF could increase the 12-lipoxygenase mRNA level by about 2-fold with a lag period of 10 h, which was well parallel with the increase in the enzyme activity. The induction of the 12-lipoxygenase mRNA by EGF was completely blocked by 35 microM cycloheximide, if present in culture medium during EGF treatment, indicating that a de novo protein biosynthesis was essential for EGF-induced 12-lipoxygenase mRNA expression. Our data provide the first evidence for the inducibility of human 12-lipoxygenase gene expression by a growth factor.
Antibodies, Monoclonal↗
Bacterial expression, purification and partial characterization of recombinant rabbit reticulocyte 15-lipoxygenase.
The recombinant rabbit reticulocyte 15-lipoxygenase has been expressed in E. coli with a yield of about 50-70 micrograms pure lipoxygenase protein per 1 of liquid culture. The enzyme has been purified to apparent homogeneity from the bacteria lysis supernatant by ammonium sulfate precipitation, and two consecutive steps of anion exchange chromatography on a Mono Q column. As the native enzyme the recombinant lipoxygenase has a molecular mass of 75 kDa, an isoelectric point of 5.5 and oxygenates both linoleic acid (formation of 13S-hydroperoxy-9Z,13E-octadecadienoic acid) and arachidonic acid. With the latter substrate it exhibits a dual positional specificity (formation of 15S-hydroperoxy-5Z,8Z,11Z,13E-eicosatetranoic acid and 12S-hydroperoxy-5Z,8Z,10E,14Z-eicosatetraenoic acid in a ratio of 12:1). Furthermore, the enzyme is capable of oxygenating biomembranes, as indicated by HPLC analysis of esterified oxygenated polyenoic fatty acids.
Animals↗
Endonuclease activation following focal ischemic injury in the rat brain.
The structural changes which occur in chromatin DNA after ischemic brain injury are poorly understood. This study examined the appearance of double-strand DNA breaks and the temporal profile of DNA degradation following focal ischemic injury in rat brain. Focal cerebral ischemia was produced by tandem occlusion of the common carotid and proximal middle cerebral arteries. The effects of decapitation ischemia were also studied by DNA analysis. DNA was extracted by standard methods from the ischemic brain tissues and electrophoresed on a 1.5% agarose gel. With decapitation ischemia, random DNA cleavage was observed as a dense "smear" on the gel electrophoresis beginning 6 h after the ischemic insult, and increasing in amount thereafter. Focal ischemia provided DNA fragmentation, which is specific DNA cleavage at the internucleosomal linker regions, particularly in the caudoputamen. Coexisting random degradation and specific fragmentation of DNA was observed in the cortex following focal ischemia. To determine whether an endonuclease responsible for DNA fragmentation was present, nuclear proteins were extracted from normal brain nuclei and the endonuclease activity was determined using plasmid DNA and a nuclear incubation system. This demonstrated that brain nuclear proteins have Ca(2+)-dependent endonuclease activity which is related to DNA fragmentation. Ischemic injury causes both random and specific DNA cleavage in the brain, which is probably mediated by Ca(2+)-dependent endonuclease.
Animals↗
Induction of cyclooxygenase and suppression of 12-lipoxygenase in human erythroleukemia cells upon phorbol ester-induced differentiation.
When human erythroleukemia (HEL) cells were incubated with arachidonic acid, both fatty acid cyclooxygenase and arachidonate 12-lipoxygenase activities were exhibited. Subcellular localization of these enzymes were examined by differential centrifugation, and both the cyclooxygenase and the 12-lipoxygenase were present predominantly in the microsomes rather than the cytosol of the cells. The cyclooxygenase activity was stimulated by 12-O-tetradecanoylphorbol 13-acetate (TPA) in a dose-dependent and time-dependent manner. Actual increase in the cyclooxygenase protein by TPA was demonstrated by immunoprecipitation and Western blot analysis of the enzyme with the aid of an anti-cyclooxygenase antibody. Furthermore, the cyclooxygenase mRNA level increased as assessed by RNA blot analysis using a cDNA probe for the enzyme. In contrast, the TPA treatment reduced the activity of 12-lipoxygenase. By RNA blot analysis using a cDNA probe of HEL cell 12-lipoxygenase, the mRNA level of the enzyme was shown to decline by the TPA treatment. Taken together, the TPA treatment of HEL cells brought about the induction of cyclooxygenase and the suppression of 12-lipoxygenase.
Arachidonate 12-Lipoxygenase↗
Expression of human thromboxane synthase using a baculovirus system.
Human thromboxane (TX) synthase (EC 5.3.99.5) was produced by the baculovirus expression system using cDNA encoding human TX synthase [(1991) Biochem. Biophys. Res. Commun. 78, 1479-1484]. A recombinant baculovirus TXS7 was expressed in Spodoptera frugiperda Sf9 insect cells. The expressed protein was recognized by monoclonal antibody, Kon 7 raised against human TX synthase [(1990) Blood 76, 80-85]. The recombinant TX synthase catalyzed the conversion of prostaglandin (PG) H2 to TXA2 and 12-hydroxy-heptadecatrienoic acid (HHT). Both conversions of PGH2 to TXA2 and HHT by the expressed TX synthase were completely inhibited by a specific TX synthase inhibitor, OKY-046 (5 microM).
Animals↗
Decreased messenger RNA of arachidonate 12-lipoxygenase in platelets of patients with myeloproliferative disorders.
On the basis of the previous work by Okuma and Uchino [Blood 54, 1258-1271, 1979], three patients with myeloproliferative disorders were investigated with a special reference to arachidonate 12-lipoxygenase in their platelets. The cytosol of the patients' platelets showed a markedly reduced activity of arachidonic acid oxygenation to 12-hydroperoxy acid. A peroxidase-linked immunoassay for the 12-lipoxygenase demonstrated only 7-12% of the normal level of the enzyme protein in the cytosol fraction of platelets. Furthermore, 12-lipoxygenase mRNA level was determined quantitatively by a reverse transcriptase-polymerase chain reaction with an internal standard cRNA which was synthesized by in vitro transcription of human platelet 12-lipoxygenase cDNA with a 105-bp deletion. The 12-lipoxygenase mRNA content was 4.7 +/- 2.0 (mean +/- S.D.) ng/10(11) platelets in 13 normal subjects. In contrast, the mRNA content was as low as 0.15, 0.11 and 0.10 ng/10(11) platelets in the three patients. Taken together, the 12-lipoxygenase deficiency in these patients was attributable to the decreased 12-lipoxygenase mRNA level and thus the impaired synthesis of the enzyme protein in their platelets.
Antibodies, Monoclonal↗