Biomedical subjects

H Nakagawa

Publications and source records attributed to H Nakagawa.

At least 19 recordsLinked to original sources

PubMed1992

Circadian variation of [3H]dopamine handling in adrenal chromaffin cells of mice.

Circadian variation of exogenous [3H]dopamine handling by adrenal chromaffin cells was examined using mice habituated to 08.00-20.00 h light cycle. Experiments were carried out at 00.00, 06.00, 12.00 and 18.00 h. [3H]Dopamine-derived radioactivity reached a peak at 2 min then decreased rapidly except at 18.00 h, when no particular peak was observed at 2 min but at 30 min in both intact and denervated adrenals. In intact adrenals, the 2-min peak at 06.00 h was suppressed by corticosterone while in denervated adrenals the 2-min peak remained. The present result indicates that quick turnover of [3H]dopamine was suppressed by a steroid surge at about 2 h before light to dark alteration. Normal innervation is necessary for corticosterone-induced suppression.

Adrenal Glands↗

PubMed1992

Inactivation of substance P by granulation tissue-derived gelatinase.

An active gelatinase has been purified from the conditioned medium of granulation tissue culture formed by carrageenin injection in rats. The purified gelatinase gave a single band corresponding to a M(r) of 57 kDa on both sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and SDS-gelatin PAGE. The granulation tissue-derived gelatinase selectively cleaved the Gln6-Phe7 bond of substance P (SP) with a Km of 0.17 mM and a Vmax of 0.027 nmol SP7-11/min/micrograms protein, resulting in the generation of biologically inactive fragments, SP1-6 and SP7-11. Our data suggest that the gelatinase produced by granulation tissue participates in the inactivation of SP in the inflammatory site.

Animals↗

PubMed1992

Inhibition of nicotinic acetylcholine receptor-mediated secretion and synthesis of catecholamines by sea urchin toxin in cultured bovine adrenal medullary cells.

We previously reported the partial purification and characterization of a toxic substance (sea urchin toxin) isolated from the pedicellariae of the sea urchin Toxopneustes pileolus (Nakagawa and Kimura, Jpn J Pharmacol 32: 966-968, 1982). In the present study, we examined the effect of sea urchin toxin on catecholamine secretion and synthesis in cultured bovine adrenal medullary cells. Sea urchin toxin inhibited the secretion of catecholamines stimulated by carbachol and nicotine but not by veratridine or a high concentration of K+. The toxin inhibited the carbachol-evoked influx of 22Na+ and 45Ca2+ at concentrations similar to those for catecholamine secretion. The inhibition of catecholamine secretion by sea urchin toxin was not overcome by increasing the concentration of carbachol. Preincubation of cells with the toxin caused a time-dependent inhibition in the secretion stimulated by carbachol even when the toxin was removed from the incubation medium. The toxin suppressed catecholamine synthesis and tyrosine hydroxylase activity in carbachol-stimulated cells. In addition, sea urchin toxin inhibited [3H]phencyclidine binding to adrenal medullary cells whereas it did not alter cyclic GMP accumulation caused by muscarine. Further purified fractions from sea urchin toxin by concanavalin A affinity column chromatography also inhibited carbachol-evoked secretion of catecholamines. These results suggest that sea urchin toxin inhibits carbachol-enhanced secretion and synthesis of catecholamines by suppression of nicotinic acetylcholine receptor-mediated Na+ influx and subsequent Ca2+ influx in cultured adrenal medullary cells.

Adrenal Medulla↗

PubMed1992

Purification and initial characterization of the proteasome from the higher plant Spinacia oleracea.

The proteasome (multicatalytic protease complex), a high molecular weight protein complex, has been purified from spinach leaves by successive chromatography on DEAE-cellulose, Bio-Gel A-1.5m, DEAE-TOYOPEARL 650C, and DEAE-5PW. The molecular mass was estimated to be 850 kDa by gel filtration. Polyacrylamide gel electrophoresis of the proteasome gave a single protein band under nondenaturing conditions and at least 10 bands in the range of 21-32 kDa in the presence of sodium dodecyl sulfate. By electron microscopy after negative staining with uranyl acetate, the proteasome from spinach appeared as symmetrical ring-shaped particles. The substrate specificity of proteasomes indicates that they contain at least three types of activity, namely, chymotrypsin-like, Staphylococcus aureus V8 protease-like, and trypsin-like activities. The former two activities were enhanced by poly-L-lysine or sodium dodecyl sulfate. Moreover, we examined the immunological reactivities of proteasomes from various eukaryotes. As a result, cross-immunoreactivities of some subunits were observed. These properties of the proteasome are similar to those of proteasomes isolated from various other eukaryotic sources.

Amino Acid Sequence↗

PubMed1992

Effect of orbital enucleation on glucose homeostasis and morphology of the suprachiasmatic nucleus.

In rats there is a direct neural connection called the retinohypothalamic tract (RHT) from retinal ganglion cells to the ventrolateral part of the suprachiasmatic nucleus (SCN), which has neurons containing vasoactive intestinal polypeptide (VIP)-like substance. Previously, we observed that bilateral orbital enucleation (blinding) caused temporary suppression of the hyperglycemic response to intracranial injection of 2-deoxy-D-glucose (2DG) from week 4 to 6 after blinding. Moreover, bilateral lesions of the SCN had a similar effect. From these findings, we supposed that the neurons responsible for the hyperglycemic response to 2DG were present in the SCN, that after blinding these neurons temporarily lost their activity, and that this functional change was reflected in the morphology of the SCN. To investigate this possibility, we examined the morphological changes of the SCN by Nissl staining and immunohistochemical studies with anti-VIP and anti-peptide histidine isoleucine (PHI) antibodies in blinded rats, and the relationship between these morphological changes and the hyperglycemic response to 2DG. After surgical blinding, we observed following changes. (1) The optic chiasm became thinner. (2) The SCN became displaced rostrally. (3) The density of neurons in the middle to caudal part of the SCN, where the retinal ganglion cells projected, decreased markedly without change in cell number during the period when the hyperglycemic response to intracranial injection of 2DG was temporarily suppressed after blinding. The first and second changes seemed to reflect reduction of fibers and axon terminals of retinal ganglion cells and their innervation, respectively. As the third change was parallel with suppression of the hyperglycemic response to 2DG injection, it may reflect functional change of the neurons in the SCN that are responsible for the hyperglycemia due to 2DG.

Animals↗

PubMed1992

Differences between vasorelaxant responses of the canine and human mesenteric arteries and veins to amrinone.

Amrinone induced similar degrees of relaxation in human mesenteric arteries and veins contracted with KCl, but exerted a more potent vasodilator effect in canine mesenteric veins than in arteries. Dibutyryl cAMP had a stronger effect on KCl-induced contraction in canine mesenteric veins than in arteries. These results suggest that amrinone promotes a different vasodilating action in human and canine mesenteric vessels, possibly via different sensitivity to cAMP in each vascular smooth muscle.

Amrinone↗

PubMed1992

[Radiation therapy for patients with obstructive jaundice caused by carcinoma of the extrahepatic biliary system].

From February 1980 through September 1990, 92 patients with obstructive jaundice resulting from biliary tract cancer registered at Shikoku Cancer Center Hospital or Ehime University Hospital. Radiation therapy (RT) was used to treat 38 of these patients (30 with carcinoma of the extrahepatic bile duct, excluding ampulla of Vater, and eight patients with carcinoma of the gallbladder). Of 38 patients, 11 underwent intraoperative radiation therapy (IORT), and 27 were treated by external radiation therapy (ERT) alone. In contrast, 54 patients (39 with carcinoma of the extrahepatic bile duct and eight with carcinoma of the gallbladder) were not treated by RT. All jaundiced patients received external and/or internal biliary drainage of some kind. Among patients undergoing biliary drainage with a catheter, 21 patients who underwent RT (four with IORT) survived significantly longer than 19 patients who did not (generalized Wilcoxon test: p less than 0.05). There were no significant differences in survival between 7 patients with recanalization and 11 patients with no recanalization. Concerning the survival of laparotomized patients, excluding those with complete resection or perioperative death, eight patients treated with postoperative ERT survived longer than 12 patients who did not have postoperative ERT (not significantly). Eleven patients underwent IORT. A patient with unresectable carcinoma of the hilar bile duct survived 2 years and 3 months after a combination treatment of ERT and IOTR. In four of eight autopsied patients, radiation effects of Grade II were observed (Oboshi and Shimosato's evaluation system for the histological effects of radiation therapy). Our experience suggests that RT is effective in patients with obstructive jaundice caused by carcinoma of the biliary system.

Adenocarcinoma↗

PubMed1992

Molecular cloning and expression of chicken C-terminal Src kinase: lack of stable association with c-Src protein.

Cloning and sequencing of chicken C-terminal Src kinase (CSK), a tyrosine kinase that phosphorylates the regulatory C-terminal tyrosine residue present on cytoplasmic tyrosine kinases of the Src family, demonstrated a high degree of interspecies conservation as well as src homology 2 and 3 domains N-terminal to the kinase domain. The lack of autophosphorylation sites distinguishes CSK from other tyrosine kinases. CSK is unique and does not belong to a gene family, suggesting that it may phosphorylate other members of the Src family of tyrosine kinases in addition to c-Src. Since complex formation between c-Src and CSK seemed a likely regulatory step in the control of c-Src kinase activity, such an association was investigated by immunoprecipitation and Western blotting as well as intracellular localization studies. Although some portions of CSK were found in a membrane fraction, no complex formation between CSK and c-Src was observed, suggesting that the src homology 2 domain of CSK does not play a role in the direct interaction of c-Src.

Amino Acid Sequence↗

PubMed1992

Measurements of CSF biochemical tumor markers in patients with meningeal carcinomatosis and brain tumors.

CSF beta-glucuronidase, polyamines and carcinoembryonic antigen (CEA) were analyzed in 16 patients with meningeal carcinomatosis from solid tumor in systemic organs, 27 with benign brain lesions, 18 with primary brain tumors, 14 with metastatic brain tumors and 5 with leptomeningeal dissemination of other malignant diseases. Beta-glucuronidase levels in all cases of meningeal carcinomatosis, meningeal gliomatosis and meningeal lymphoma were higher than 100 micrograms/dl/hr; on the other hand, levels in all cases of benign brain lesions were below 100 micrograms/dl/hr. Levels of beta-glucuronidase and polyamines were not high in the cases with positive cytology after tumor resection. Polyamine levels were below 0.05 nmol/ml in all cases after resection of the metastatic brain tumor. Cystic fluid of malignant tumors showed high levels of beta-glucuronidase and polyamines. On the other hand, the levels of polyamines in the cystic fluid of benign tumor were low, although the levels of beta-glucuronidase were high. Some cases of meningeal carcinomatosis with high levels of serum CEA did not show high levels of CSF CEA. For metastatic brain tumors, the cases with intraparenchymal tumors, especially with dural attachment showed high levels of beta-glucuronidase and CEA preoperatively, but they returned to normal after surgery. In cases of meningeal carcinomatosis treated by intrathecal chemotherapy with methotrexate (MTX) and cytosine arabinoside (Ara-C), CSF beta-glucuronidase reflected the neurological status better than the cell count decreased rapidly following chemotherapy and beta-glucuronidase was considered as a useful CSF marker in cases of meningeal carcinomatosis to monitor the course of the disease. The same situation was observed in CSF CEA and CEA was also considered as a useful marker when CEA levels in CSF are higher than those in serum.

Antineoplastic Agents↗

PubMed1992

Diagnosis and treatment of patients with meningeal carcinomatosis.

The records of thirty-four patients with meningeal carcinomatosis treated at our hospital between 1984 and 1990 were reviewed. The sources, histologies, metastatic lesions outside the central nervous system, the history of the treatment of primary lesions and intraparenchymal of metastatic brain tumors and the period from the diagnosis of primary lesions and the treatment of intraparenchymal metastatic brain tumors to the diagnosis of meningeal carcinomatosis were investigated. Meningeal carcinomatosis was diagnosed and by neurological signs, CSF cytology, CT scan and MRI. Each patient was given a 5 mg single dose of methotrexate (MTX) alone or combined with 20 mg cytosine arabinoside (Ara-C) administered by intrathecal injection via an Ommaya reservoir and standard lumbar puncture with or without radiotherapy. Following intrathecal chemotherapy 22 of 29 patients showed symptomatic improvement of meningeal irritation and in 10 of 29 patients with cranial nerve impairment amelioration of symptoms was also observed. Moreover, CSF cytology became negative in 10 of 29 patients after a full course of intrathecal chemotherapy. Neurotoxicity Leukoencephalopathy, a neurotoxic effect of intrathecal chemotherapy was not observed in any of the patients. From these results, MTX in small doses is recommended for intrathecal chemotherapy of meningeal carcinomatosis to prevent neurotoxicity.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1992

Local spiking interneurons controlling the equilibrium response in the crayfish Procambarus clarkii.

1. In the crayfish brain, the responses of local spiking interneurons to body roll simulated by bending of statocyst hairs, were investigated with intracellular recording and staining techniques. The neurons had two separate branching portions in the protocerebrum and the deutocerebrum. They were named as type-I local neurons and further classified into 5 types (ac-U, vplc-U, vplc-B, vupc-U, vupc-B). 2. Vupc-U neurons showed excitatory responses and vplc-U neurons showed inhibitory responses to inward hair deflection of the statocyst ipsilateral to their deutocerebral branches. The other 3 types were of mixed populations of the interneurons showing either excitatory or inhibitory responses to the stimulation. 3. Of 10 type-I local neurons showing excitatory responses to inward hair deflection, 6 interneurons had output effects on oculomotor and/or descending neurons. All these 6 interneurons showed large EPSPs and much higher frequency of spikes to the hair stimulation than those of the other 4. All 8 type-I local neurons that showed inhibitory responses had no output effects. 4. Type-I local neurons controlled two equilibrium responses, compensatory eye movement and righting reflex, either simultaneously or independently.

Acoustic Stimulation↗

PubMed1992

Postoperative osteomyelitis due to Mycobacterium fortuitum. A case report.

A rare case of osteomyelitis of the tibia caused by Mycobacterium fortuitum which developed after closed intramedullary Küntscher nail fixation is reported. After extraction of the nail, combination therapy with antituberculous drugs, ofloxacin, and interleukin 2 was undertaken and bony union was achieved. Since a bone cyst formed during union, curettage and conventional cancellous bone grafting were performed. The patient is now pain-free even with prolonged weight-bearing. The success of treatment in this case is in contrast to other reports of the disease.

Adolescent↗

PubMed1992

Increase in nucleoside diphosphatase in rat brain striatum lesioned with kainic acid.

The activity of ammoniagenesis from guanine nucleotides was found to increase significantly in rat brain after infusion of kainic acid into the striatum. Among the enzymes involved in degrading guanine nucleotides, nucleoside diphosphatase was markedly increased in the lesioned striatum. The enzyme activity began to increase 2 days after the infusion, and reached the maximum on the 13th day, the level being 4 times as high as that of the intact contralateral region. The increased activity was due to Type L enzyme, judging from its substrate specificity. Puromycin and cycloheximide inhibited this increase, indicating that the increased activity resulted from an increase in the net synthesis of the enzyme. These findings suggest that Type L NDPase might play some important roles in gliosis after neuronal lesion.

Acid Anhydride Hydrolases↗

PubMed1992

Assignment of the human cytochrome P-450 nifedipine oxidase gene (CYP3A4) to chromosome 7 at band q22.1 by fluorescence in situ hybridization.

We have used a full length cDNA clone (2.2 kb) for the human cytochrome P-450 nifedipine oxidase (CYP3A4) enzyme as a probe to determine its chromosome localization by fluorescence in situ hybridization. CYP3A4 was mapped on R-banded human prometaphase chromosomes, and the precise localization of CYP3A4 on chromosome 7 was further confirmed by a delineation of G-banded pattern on the same prometaphase chromosomes through a combination of UV-filter. We assigned CYP3A4 to chromosome 7 at q22.1.

Cells, Cultured↗

PubMed1992

Gastrointestinal endoscopy in Henoch-Schönlein purpura.

Gastrointestinal (GI) endoscopy was performed in seven patients with Henoch-Schönlein purpura (HSP). In two patients there were no cutaneous lesions at the time of endoscopy, but inflammation of the duodenum, especially of the second part, led to suspicion of the disease. Upper GI endoscopy showed abnormalities in six of seven cases, and sigmoidoscopy in one of four cases. The changes were more marked in the second part of the duodenum rather than in the bulb or the stomach. The endoscopic findings included redness, swelling, petechiae or haemorrhage, erosions and ulceration of the mucosa. Histology of the mucosal biopsy specimens revealed non-specific inflammation with positive staining for IgA in the capillaries, but failed to show vasculitis. Upper GI endoscopy, including study of IgA, can be useful in the diagnosis of HSP. Colonoscopy is less helpful, especially if limited to the sigmoid colon.

Adolescent↗

PubMed1992

Arginine and lysine residues as NADH-binding sites in NADH-nitrate reductase from spinach.

Chemical modifications of spinach leaf nitrate reductase, and its 28,000 M(r) fragment with phenylglyoxal, 2,3-butanedione and pyridoxal phosphate reduce the catalytic activity of the enzyme. The kinetics of the modification indicate a rapid inactivation followed by a slower rate of inactivation. NADH-nitrate reductase, NADH-cytochrome c reductase and NADH-ferricyanide reductase activities of the nitrate reductase complex are inactivated at a faster rate when compared to the loss of FMNH2-nitrate reductase and reduced methyl viologen (MVH)-nitrate reductase activities. NADH protects the inactivation of NADH-ferricyanide reductase activity of the 28,000 M(r) fragment of nitrate reductase. These data suggest that nitrate reductase contains active sites of arginine and lysine residues that are involved in the NADH binding site of the enzyme.

Amino Acid Sequence↗

PubMed1992

Shifting of dural arteriovenous malformation from the cavernous sinus to the sigmoid sinus to the transverse sinus after transvenous embolization. A case of left spontaneous carotid-cavernous sinus fistula.

The angiographic features of left spontaneous carotid-cavernous sinus fistula and multiple dural arteriovenous malformations that developed after transvenous embolization are described. A dural arteriovenous malformation involving the left sigmoid sinus was demonstrated, along with a marked decrease in size of the left carotid-cavernous sinus fistula and the disappearance of venous drainage from the left cavernous to the right cavernous sinus after embolization with spring coils via the left superior ophthalmic vein. The dural arteriovenous malformation of the left sigmoid sinus subsequently extended to the transverse sinus after partial embolization of the sigmoid sinus. Finally, a dural arteriovenous malformation involving the left transverse sinus developed, with the disappearance of the arteriovenous malformation affecting the sigmoid sinus and left carotid-cavernous sinus fistula following complete embolization of the sigmoid sinus via the left transverse sinus.

Adult↗

PubMed1992

Light enhances sympathetic and suppresses vagal outflows and lesions including the suprachiasmatic nucleus eliminate these changes in rats.

Neurons in the suprachiasmatic nucleus (SCN) are suggested to be involved in the mechanism of glucose homeostasis. This mechanism was examined by studies on the effect of illumination on the activity of autonomic efferents to the adrenals, pancreas and liver. Exposure of one eye of anesthetized rats to light enhanced the efferent activity of the adrenal nerve and suppressed that of vagal pancreatic and hepatic nerves. No change in efferent activities of these nerves was observed on light-stimulation of rats with lesions that included the bilateral SCN. These findings indicate that light signals modulate visceral functions including metabolic processes through the retinohypothalamic tract probably via the SCN to autonomic efferent pathways innervating visceral organs.

Adrenal Glands↗