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Biomedical subjects

J Ito

Publications and source records attributed to J Ito.

At least 325 records · Page 18Linked to original sources
PubMed1984

The absence of differentiation-promoting response of astroglioma cells to glia maturation factor.

The effects of glia maturation factor (GMF) on cell proliferation and differentiation were investigated with 3 astroglioma cells (GE-12, C6, and GA-1), Schwannoma-like cells (354A), and mixed glioma cells (LRM-55). In the exponentially growing phase the growth rates of all glioma cells were enhanced by GMF regardless of the presence or absence of serum, but the factor failed to make the saturation density surpass the control level observed in the medium without GMF even in the chemically defined medium (N2 medium). GMF markedly lowered the saturation density of Schwannoma-like cells in N2 medium. Although GMF increased the intracellular content of S-100 protein 10-fold and 2',3'-cyclic nucleotide phosphohydrolase activity 1.5-fold in Schwannoma-like cells, GMF conversely decreased the S-100 contents and glycerol phosphate dehydrogenase activity in astroglioma cells. All the astroglioma cells secreted into the culture medium large quantities of a growth-promoting factor(s) which had similar chemical properties to those of GMF and stimulated the proliferation of normal glioblasts; but Schwannoma-like cells did not, although they produced a small amount of such a factor(s). These findings imply that astroglioma cells are deprived of the differentiation-promoting response to GMF while Schwannoma-like cells still preserve the response in addition to the proliferative response to GMF.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗
PubMed1984

Projections to eye movement-related pause neuron region in cat using HRP.

The origins of the afferent connections to the eye movement-related pause neurons in cats were examined using retrograde transport of horseradish peroxidase with wheat germ agglutinin. The major input sources to the pause neuron region were nucleus prepositus hypoglossi, medial vestibular nucleus, gigantocellular reticular nucleus, parvocellular reticular nucleus, nucleus reticularis tegmentis pontis, nucleus reticularis pontis caudalis, nucleus reticularis pontis oralis, and superior colliculus. Less heavily labeled sources included the lateral and descending vestibular nuclei, the locus ceruleus, and the dorsal raphe.

Animals↗
PubMed1984

Antibodies specific for the phi 29 terminal protein inhibit the initiation of DNA replication in vitro.

The phi 29 DNA-terminal protein serves as a primer for the initiation of DNA replication by covalently binding the first nucleotide in the DNA chain. Two distinct antibodies were used for functional analysis of this protein. One antibody was raised against sonicated phi 29 DNA-protein complex isolated from phage virions (anti-TP). The other antibody was raised against a conjugate of bovine serum albumin and a synthetic peptide corresponding to the carboxy-terminal of the phi 29 terminal protein (anti-gp3C), which was predicted from the nucleotide sequence of phi 29 DNA. Both antibodies react with native phi 29 terminal protein as determined by immunoprecipitation and enzyme-linked immunosorbent assay. Both antibodies specifically inhibit the complex-forming reaction between the phi 29 terminal protein and dAMP, the first nucleotide of phi 29 DNA.

Amino Acid Sequence↗
PubMed1984

Replication of bacteriophage phi 29 DNA in vitro: the roles of terminal protein and DNA polymerase.

phi 29 DNA replication is initiated by the formation of a covalent complex between the viral-coded terminal protein and dAMP (TP-dAMP). This initiation reaction system has been reconstituted from two phage-encoded proteins, the terminal protein and DNA polymerase. The phi 29 DNA polymerase was purified from phage-infected cells by using poly(dA) X p(dT)12-18 as an assay template. The purified polymerase has an apparent molecular mass of 68 kDa in its native form and it appears to function as a monomer. The terminal protein was purified to homogeneity from Escherichia coli cells harboring a cloned plasmid that contained a phi 29 gene 3 segment. The molecular mass of the purified terminal protein was about 30 kDa in both the denatured and the native form. The protein apparently functions as a monomer. When the terminal protein and DNA polymerase were incubated in the presence of dATP, Mg2+, and phi 29 DNA-protein as template, the terminal protein bound covalently to dAMP. This reaction did not require ATP. In addition, these two purified fractions catalyzed DNA chain elongation from both ends of phi 29 DNA, yielding the expected 9- to 12-base fragment when assayed in the presence of 2',3'-dideoxycytidine triphosphate. These results indicate that phi 29 DNA polymerase catalyzes formation of the terminal protein-dAMP complex and can also catalyze chain elongation at least 9-12 bases from both ends of phi 29 DNA.

Bacillus subtilis↗
PubMed1984

CT findings of medulloblastoma.

Computed tomography (CT) of 11 patients with medulloblastoma was evaluated. 6 of them showed solid, nearly homogenous lesions and definite enhancement after infusion of contrast medium. However, 5 cases showed heterogenous mass lesions composed of the areas of low density and iso- or slightly high density which was attenuated by contrast enhancement. Histological examinations revealed that 2 cases had differentiated medulloblastomas, but the other 3 typical medulloblastomas. It should be reminded in the differential diagnosis of cerebellar tumors of pediatric patients that medulloblastoma can reveal heterogenous mass in CT scan.

Cerebellar Neoplasms↗
PubMed1984

Effects of ethanol applied by electrosmosis on neurons in the lateral and medial vestibular nuclei.

Electrophysiological studies were performed to elucidate the effects of ethanol on neuron activities in the lateral vestibular nucleus (LVN) and medial vestibular nucleus (MVN) of cats using an electrosmotic and microiontophoretic method. The LVN and MVN neurons were classified into two types according to the firing pattern and latency of the first spike with vestibular nerve stimulation: monosynaptic and polysynaptic neurons. Electrosmotic application of ethanol up to 200 nA produced a dose-dependent inhibition of spikes of the LVN monosynaptic neurons with vestibular nerve stimulation and iontophoretically applied glutamate, but no significant alterations of the spikes of the LVN polysynaptic neurons. Acetylcholine-induced firing in the LVN monosynaptic neurons was also inhibited by ethanol. In the MVN, spike generation of the monosynaptic and polysynaptic neurons with vestibular nerve stimulation and iontophoretically applied glutamate remained unaltered with ethanol up to 200 nA. These results indicate that ethanol predominantly inhibits synaptic transmission of the LVN monosynaptic neurons, probably by acting on the postsynaptic cell bodies.

Acetylcholine↗
PubMed1984

Internuclear fiber connections of vestibular nuclear complex. A horseradish peroxidase study.

Internuclear fiber connections among the superior (SVN), lateral (LVN), medial (MVN) and descending (DVN) vestibular nuclei were examined in cats using retrograde transport of horseradish peroxidase (HRP). HRP was microiontophoretically applied in the respective vestibular nucleus at doses of 300-500 nA for 5-10 min, and with the treatment the HRP injection site was limited to 0.2-0.5 mm in diameter within the nucleus. Major commissural connections were found between the bilateral SVN and between the bilateral DVN. Minor commissural connections were observed from MVN to SVN, LVN and MVN, from DVN to LVN, and from LVN to the contralateral LVN. In the ipsilateral vestibular nuclei, fiber connections were found from LVN to SVN, from MVN to SVN, LVN and DVN, and from DVN to SVN and LVN.

Animals↗
PubMed1984

[Minute gallbladder cancer--case report with suggestions regarding a possibly unique histogenesis].

A 35-year-old woman with minute gallbladder cancer is presented. Cholecystectomy for gallstones resulted in recurrent colic lasting for a few years. Examination of the resected bladder under a dissection microscope disclosed a minute polypoid tumor with cylindroid appearance measuring 2.0 X 0.5 mm; it was located on a thin membraneous stalk in the neck region. Histologically, the tumor consisted chiefly of well-differentiated adenocarcinoma, in its periphery there were adenomatous residues; the stalk was free of neoplastic change. Blood group substances were completely absent in the cancerous tissues, they were present in adenomatous tissues. We hypothesize that the present cancer derived from the minute gallbladder adenoma via malignant change at an early stage development, suggesting a unique mode for an adenoma-carcinoma sequence in the gallbladder. The present case is believed to be the smallest cancer among reported cases and we propose to define minute gallbladder cancer as that less than 5 mm in maximum diameter.

Adenocarcinoma↗
PubMed1984

Experimental vestibular pharmacology: a minireview with special reference to neuroactive substances and antivertigo drugs.

Neurotransmitters and neuromodulators involved in the function of vestibular nuclei were reviewed with special reference to drugs used for treatment of motion sickness and vertigo. Biochemical, histochemical and electrophysiological studies have demonstrated that acetylcholine is a transmitter candidate from the afferent vestibular nerve to the lateral vestibular nucleus (LVN), because acetylcholine satisfies most criteria for a chemical transmitter in the central nervous system. It is unlikely, however, that monoamines such as noradrenaline, dopamine and serotonin are transmitters in the vestibular neurons, since cell bodies and nerve terminals containing the monoamines have not been detected yet in the vestibular nuclei. Although histamine and H1-receptor blockers inhibit neuron activities in the vestibular nuclei, it is unclear at present whether histaminergic system is directly related to the function of vestibular neurons. It has been established that GABA is an inhibitory transmitter from the cerebellar Purkinje cells to the LVN neurons. Diazepam is considered to enhance the GABA effect on the LVN, thereby modifying the vestibular neuronal firing. Enkephalin-containing cell bodies and nerve terminals are found in the medial vestibular nucleus, and a few substance P-containing neurons have been observed in the vestibular nuclei. However, the functional role of these peptides on the vestibular system remains to be determined. Unlike histamine H1-receptor blockers, vasodilators such as cinnarizine, ifenprodil and adenosine triphosphate, which are effective in treatment of vertigo, produce an enhancement of responsiveness of neuron activities in the vestibular nuclei, probably as a result of an increase in blood flow in the brain.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1984

[Effects of PS-K as adjuvant therapy for primary lung cancer--an autopsy case].

A 57-year-old woman underwent left lower lobectomy for primary lung cancer (papillary adenocarcinoma, T2NOMO). Despite postoperative adjuvant immunochemotherapy with 5-Fu, Carboquone and PS-K, bone metastases were recognized at 9 months after the surgery. She received radiation therapy and was administered PS-K alone, 3.0 g daily. As a result, long-term good condition was maintained with a positive PPD skin test. The bone metastases developed slowly, and the patient survived 5 years and 8 months after the operation. At autopsy, no obvious metastatic lesions were identified except for the bone metastases. The cause of her death was thought to be acute renal failure due to severe hemorrhage from an esophageal ulcer. Moreover, she was doomed because of advanced polycystic disease.

Adenocarcinoma, Papillary↗
PubMed1984

Electrophysiological and HRP studies on feedback loop between inferior olivary nucleus and lateral vestibular nucleus in the cat.

The role of input from the inferior olivary nucleus (IO) of decerebellate cats were studied on the lateral vestibular nucleus (LVN) neurons which were monosynaptically activated by vestibular nerve stimulation. Out of 168 monosynaptic neurons, test stimuli to the contralateral IO elicited a monosynaptic spike in 43 neurons and an antidromic spike in 9 neurons. Conditioning stimulus applied to the IO preceding vestibular nerve stimulation produced an inhibition of spike generation in 22 other LVN neurons upon the nerve stimulation. When horseradish peroxidase (HRP) was iontophoretically applied into the immediate vicinity of the LVN monosynaptic neurons, HRP-reactive cells were found in the dorsal cap and beta-nucleus of the contralateral IO. These results suggest that the LVN neurons monosynaptically activated by vestibular nerve stimulation receive both excitation and inhibition from the IO.

Action Potentials↗
PubMed1984

Cerebral hemodynamics in patients with moyamoya disease. A study of the epicerebral microcirculation by fluorescein angiography.

Fluorescein angiography was performed in 12 hemispheres of eight young patients with moyamoya disease to study the epicerebral microcirculation. Regional circulation time and the time interval between carotid injection of the dye and first filling of the cortical arteries were various and prolonged in the most parts. There were nonfilling areas by carotid injection of the dye in six hemispheres. By venous injection, the dye appeared in all vessels of the exposed areas. Extravasation of the dye was seen in four hemispheres. The degree of these abnormalities of the epicerebral microcirculation was well correlated with the findings in conventional cerebral angiography.

Adolescent↗
PubMed1983

A novel DNA polymerase induced by Bacillus subtilis phage phi 29.

A novel DNA polymerase induced by Bacillus subtilis bacteriophage phi 29 has been identified. This polymerase can be separated from host DNA polymerase, by fractionation of extracts prepared from phage infected cells, using phosphocellulose chromatography. The isolated polymerase prefers poly(dA)oligo(dT) as template. The DNA polymerase isolated from the cells infected with a gene 2 temperature sensitive mutant (ts2) showed greater heat-lability than that induced by wild type phi 29. The ts2 DNA polymerase was also thermolabile for its activity in the formation of a covalent complex between phi 29 terminal protein and dAMP, the initiation step of phi 29 DNA replication. These findings indicate that gene 2 is the structural gene for a phi 29 DNA polymerase required for the complex formation step of DNA initiation.

Bacillus subtilis↗