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Biomedical subjects

H Ichikawa

Publications and source records attributed to H Ichikawa.

At least 271 records · Page 15Linked to original sources
PubMed1995

[A case of hemichorea presenting with inattention and denial of involuntary movement].

We report a case of hemichorea presenting inattention and denial of involuntary movement. A 64-year-old right-handed man was hospitalized with acute hemichorea on the right side of the body. The patient had hemichorea which was frequently followed by purposeful movement such as fumbling with his glasses or combing his hair. He claimed that the involuntary movements were habits showing both inattention and denial of the involuntary movements. These symptoms were very unique. On MRI of the brain, T2 elongated spots were detected at the bilateral pallidum, suggesting occulusive cerebrovascular disease. On 123I-IMP-SPECT hypoperfusion was observed at the right cerebral basal ganglia extending to the right medial frontal lobe. We supposed that this inattention and denial of involuntary movements were caused by dysfunction of the system connecting the medial frontal lobe with basal ganglia which was presented as hypoperfusion on SPECT.

Acute Disease↗
PubMed1995

Characteristics of Roman character input in Japanese word processing on keystroke interval time.

This study clarifies the characteristics of the time keys that are taken to enter Roman letters for Japanese sentences. First, test the appearance frequency of two consecutive characters of the alphabet in the input of English sentences and in the input of the Roman characters of Japanese sentences. Based on these results, we analyzed the features of stroke frequency of the keys in the Roman character input. Based on the result of the analysis, we clarified the features of the keystroke interval time for two consecutive characters in the Roman character input. Then, keys were struck to enter Japanese sentences for a fixed period of time and a test was made for the characteristics. As a result, the following points were clarified: 1) The time keys struck were divided into two large groups. One for two consecutive alphabet letters that corresponded to Kana, or the Japanese syllabary, and the other with no correspondence. The former had smaller values for the mean time and deviations, and the latter had larger values for them. 2) The subjects who struck a larger number of keys per unit time took less time in typing two consecutive letters which did not correspond to Kana.

Adult↗
PubMed1994

c-Fos induction in the rat spinal dorsal horn partially deafferented by dorsal rhizotomy.

The 4th and 5th segments of the lumbar (the L4 and L5) dorsal horn receive primary input from the sciatic receptive fields through the L4 and L5 dorsal roots. Noxious stimulation of the hindpaw with formalin induces c-Fos in neurons in superficial laminae (I and II) of these dorsal horn segments. Rhizotomy of the L5 dorsal root 2 days before stimulation resulted in a marked reduction in the number of neurons with c-Fos protein-like immunoreactivity (fos-neurons). At 3 weeks after the L5 rhizotomy, the number of fos-neurons in laminae I and II significantly increased compared to that at 2 days post-rhizotomy. This result indicates that chronic partial deafferentation by dorsal rhizotomy increases responsiveness of superficial dorsal horn neurons to spared primary input.

Animals↗
PubMed1994

Parvalbumin, calretinin and carbonic anhydrase in the trigeminal and spinal primary neurons of the rat.

The cell-body size of parvalbumin-immunoreactive (-ir) primary neurons was measured in the trigeminal (TG) and lumber dorsal root ganglia (DRG). In the DRG, parvalbumin-ir was mostly detected in large cells (94% in the range of 600-2800 microns2). Parvalbumin-ir TG cells were smaller than similar DRG cells and yet parvalbumin-ir TG cells of < 400 microns2 (2.86%) were rare. Trichrome stains for parvalbumin, calretinin (CR) and carbonic anhydrase (CA), and for parvalbumin, calcitonin gene-related peptide (CGRP) and CA were performed to estimate possible overlap of these substances. Virtually all parvalbumin-ir DRG cells contained CA activity while a small subpopulation (28.5%) of CR-ir DRG cells lacked CA activity. All the CR-ir DRG cells that exhibited CA were also ir for parvalbumin. 31.1% of parvalbumin-ir DRG cells exhibited CR-ir while 71.5% of CR-ir DRG cells showed parvalbumin-ir. All the CR-ir DRG cells of < 400 microns2 lacked CA activity and parvalbumin-ir while all those of > 800 microns2 exhibited both activities. Approximately 30% of CR-ir DRG cells in the size range of 400-800 microns2 co-expressed CA. DRG cells co-expressing parvalbumin and CGRP were rare (approximately 1%). As was the case for the DRG, most of parvalbumin-ir TG cells exhibited CA activity (89.24%) and lacked CGRP-ir (96.6%). CR-ir TG cells were also subdivided into two groups; one with and the other without co-expression of CA. Unlike in the DRG, however, co-expression of parvalbumin and CR could never be detected in the TG.

Animals↗
PubMed1994

Regulation of the transcription of a cluster of Bacillus subtilis spore coat genes.

The pattern of transcription has been examined for a cluster of genes encoding polypeptides some or all of which are assembled into a cross-linked component of the Bacillus subtilis spore coat. Three promoters, designated PVWX, PX and PYZ, were indicated by reverse transcriptase mapping. On the basis of Northern hybridization, it appeared that the cotV, W and X genes were transcribed as a polycistronic mRNA from PVWX as well as a monocistronic cotX mRNA from Px. The cotY and cotZ genes are cotranscribed from the PYZ promoter with a smaller cotY mRNA resulting from premature termination or RNA processing. All four transcripts were synthesized late during sporulation and were not produced in mutants lacking sigma K, which directs RNA polymerase to transcribe genes in the mother-cell compartment of sporulating cells. The DNA-binding protein GerE, which affects transcription of many genes in the mother cell during the late stages of sporulation, was also shown to be involved. There was essentially no cotX mRNA in a gerE mutant and the amounts of cotVWX, cotYZ and cotY mRNAs were somewhat reduced. In vitro run-off transcription studies with sigma K RNA polymerase and GerE confirmed the presence of the three promoters, and directly showed that GerE was necessary for transcription from PX as well as enhanced transcription from the PVWX and PYZ promoters. The DNase I footprints of GerE for all three promoters were immediately upstream of the -35 regions. These GerE binding sites were compared to those in other GerE-responsive promoters and a larger consensus sequence for GerE binding was recognized. This complex transcriptional pattern of the cotVWXYZ cluster is probably necessary to ensure that an optimal amount of each protein is made for the assembly of the spore coat.

Bacillus subtilis↗
PubMed1994

An RNA-binding protein gene, TLS/FUS, is fused to ERG in human myeloid leukemia with t(16;21) chromosomal translocation.

The t(16;21)(p11;q22) translocation is a recurrent chromosomal abnormality found in several types of myeloid leukemia. We have previously demonstrated that the breakpoints of this translocation are clustered in a specific intron of the ERG gene on chromosome 21, which has recently been reported to be involved in Ewing's sarcoma. We show here that the TLS/FUS gene on chromosome 16 is fused with the ERG gene to produce the TLS/FUS-ERG chimeric transcript by this translocation. The TLS/FUS gene has been identified as a translocated gene in myxoid liposarcoma by the t(12;16)(q13;p11) translocation and encodes an RNA-binding protein that is highly homologous to the product of the EWS gene involved in Ewing's sarcoma. Thus, the TLS/FUS-ERG gene fusion in t(16;21) leukemia is predicted to produce a protein that is very similar to the EWS-ERG chimeric protein responsible for Ewing's sarcoma.

Base Sequence↗
PubMed1994

Neural parvalbumin and calretinin in the tooth pulp.

Parvalbumin- and calretinin-immunoreactivities (CR-irs) were examined in the molar tooth pulp of the rat using immunohistochemical methods. CR-ir fibers were further classified based on the tachykinin-ir revealed by a double immunofluorescence method. The rat root pulp contained three types of nerve fibers; parvalbumin-ir smooth fibers, CR-ir (TK-negative) smooth fibers and CR-ir (TK-ir) varicose fibers. These fibers projected toward the roof of the pulp chamber and pulp horn without marked ramification. In the subodontoblastic layer at the roof of the pulp chamber and pulp horn, parvalbumin-ir smooth fibers repeatedly ramified and extended varicose terminals into the odontoblastic layer. CR-ir (TK-negative) smooth fibers reached the subodontoblastic layer without marked ramification and gave rise to varicose terminals that appeared to terminate within the subodontoblastic layer. On the other hand, CR-ir (TK-ir) varicose fibers proceeded to the subodontoblastic layer at the roof of the pulp chamber and pulp horn, where they ramified and penetrated the odontoblastic layer. The present study indicates that the rat tooth pulp contains myelinated parvalbumin-ir and CR-ir (TK-negative) fibers, and unmyelinated CR-ir (TK-ir) fibers, and that they project varicose terminals to the subodontoblastic and odontoblastic layers. The central projection sites of these sensory fibers have yet to be revealed.

Animals↗
PubMed1994

Changes in c-fos induction in dorsal horn neurons by hindpaw formalin stimulation following tibial neurotomy.

The hindpaw was partially denervated by the tibial nerve transection in adult rats. At post-transection intervals varying from 2 to 168 days, the hindpaw was stimulated bilaterally by subcutaneous injection of formalin. The excitability of dorsal horn neurons was expressed as the percentage ratio of the number of formalin-induced c-fos protein-like immunoreactive neurons (fos-neurons) on the neurotomized (experimental) side to that on the un-neurotomized (control) side. At 2 days post-injury, a marked reduction in the number of fos-neurons was noted in laminae I-VII of the lumbar spinal cord. Among these, reduction was greatest in the medial 3/8 of laminae I and II (terminal field of the tibial nerve, i.e. tibial territory), and smallest in the lateral 5/8 of the same laminae (the peroneal/hip territory). The low level of c-fos induction remained unchanged for 7 days. At 14 days, the excitability of neurons in all laminae showed a marked increase compared to the post-injury days 2 and 3 combined. Thereafter, the increased level of excitability in the tibial territory was maintained throughout the post-injury period examined in this study. On the other hand, a statistically significant increase in excitability in the peroneal/hip territory was only seen between 14 and 28 days and the excitability almost returned to the baseline (days 2 and 3 post-transection combined) level at 42 days. Although deeper laminae (III-VII) contained much less formalin-induced fos-neurons, they also exhibited post-injury excitability changes with a temporal pattern similar to that of the peroneal/hip territory of laminae I and II.(ABSTRACT TRUNCATED AT 250 WORDS)

Afferent Pathways↗
PubMed1994

c-fos induction in the subnucleus caudalis following noxious mechanical stimulation of the oral mucous membrane.

c-fos expression in response to noxious mechanical stimulation of the peripheral receptive field was used to study the somatotopic representation of the oral mucous membrane and trigeminal cutaneous receptive fields in the trigeminal subnucleus caudalis and the cervical spinal dorsal horn. Fos-neurons (neurons with c-fos protein-like immunoreactivity) following stimulation of the cutaneous receptive field were found in laminae I and II of the first and second cervical segments of the spinal cord ipsilateral to the stimulation and exhibited a clear somatotopic segregation; i.e., the fos-neurons responding to receptive fields in the mandibular, maxillary, and ophthalmic divisions were arranged in a mediolateral sequence. On the other hand, fos-neurons responding to the oral mucous membrane were found in the similar laminae of the rostral pole of subnucleus caudalis bilaterally. They were all found in the dorsalmost part of the subnucleus without segregation; e.g., topographic distributions of fos-neurons resulting from the mandibular and maxillary gingival stimulations were indistinguishable. The central mechanism of trigeminal nociception is discussed with respect to the difference between intra- and extraoral receptive fields.

Animals↗
PubMed1994

Effects of an antisense napin gene on seed storage compounds in transgenic Brassica napus seeds.

To manipulate the quantity and quality of storage components in Brassica napus seeds, we have constructed an antisense gene for the storage protein napin. The antisense gene was driven by the 5'-flanking region of the B. napus napin gene to express antisense RNA in a seed-specific manner. Seeds of transgenic plants with antisense genes often contained reduced amounts of napin. In some transgenic plants, no accumulation of napin was observed. However, the total protein content of transgenic and wild-type seeds did not differ significantly. Seeds lacking napin accumulated 1.4 to 1.5 times more cruciferin than untransformed seeds, although the oleosin content was not affected. Fatty acid content and composition in the seeds of transgenic plants were also analyzed by gas chromatography. Though the total fatty acid content of the transformants was the same as that of non-transformants, there was a reduction in 18:1 contents and a concomitant increase of 18:2 in seeds with reduced napin levels. This observed change in fatty acid composition was inherited in the next generation.

2S Albumins, Plant↗
PubMed1994

Parvalbumin-like immunoreactivity in nerve fibres within human molar tooth pulps.

The root pulp contained two types of parvalbumin-immunoreactive nerve fibres, smooth and varicose. The smooth were relatively thick (mostly 3-5 microns in diameter) and sometimes had large swellings, whereas the varicose consisted of oval varicosities of 1-3 microns in long diameter with very fine strands interconnecting them. Most of the parvalbumin-immunoreactive root fibres were smooth, and the varicose were rare. Upon entering the pulp chamber, both types of fibre splayed out and ran towards the roof of the chamber and the pulp horn. In the subodontoblastic layer of the roof and horn, parvalbumin-immunoreactive fibres showed relatively straight chains of granules; they sent their granular terminals to the odontoblastic layer. Some parvalbumin-immunoreactive granules were observed in the predentine and some even in the dentine. The diameter of axons in the root pulp and the spatial distribution of terminals strongly suggest that the parvalbumin-immunoreactive fibres are mostly myelinated and sensory.

Dental Pulp↗
PubMed1994

Effects of R-56865 on transient inward current, Na(+)-Ca2+ exchange, and Ca2+ release from SR in cardiac myocytes.

Voltage-clamp studies were performed on guinea pig ventricular myocytes to clarify the action of N-(1-[4-(4-fluorophenoxy)butyl]-4-piperidinyl)-N-methyl-2-benzothiazo lamine (R-56865), an inhibitor of cardiac glycoside-induced arrhythmias. Transient inward current ((Iti)) was induced using low-K+/high-Ca2+ Tyrode solution. R-56865 (1 mM) was found to abolish I(ti). R-56865 had no influence on the peak Ca2+ current, steady-state current during the clamp, holding current, or the Ni(2+)-sensitive electrogenic Na(+)-Ca2+ exchange current. Fluorescence transients after repolarization (temporally related to the I(ti)) were abolished by R-56865 without affecting the fluorescence transients during depolarization. In separate experiments, the threshold of Ca2+ release from sarcoplasmic reticulum (SR) by the Ca2+ current was found to be unchanged, whereas Ca2+ transients (presumably triggered by Ca2+ entry through the Na(+)-Ca2+ exchanger) were depressed. Our results suggest that R-56865 inhibits spontaneous Ca2+ release from the SR when it is mediated by Ca2+ entry through the Na(+)-Ca2+ exchanger but that it has no direct effect on the well-known "physiological" Ca(2+)-induced Ca(2+)-release mechanism from SR.

Animals↗
PubMed1994

Oxidant stress inhibits Na-Ca-exchange current in cardiac myocytes: mediation by sulfhydryl groups?

The effects of oxidant stress (xanthine oxidase plus hypoxanthine or photoactivation of rose bengal) on the Na(+)-Ca(2+)-exchange current were studied in guinea pig ventricular myocytes with the use of voltage-clamp techniques. Oxidant stress depressed both the Ni(2+)-sensitive and extracellular calcium concentration ([Ca2+]o)-activated current in a time-dependent manner (e.g., xanthine oxidase plus hypoxanthine inhibited the Ni(2+)-sensitive current at +60 mV from 6.81 +/- 3.24 to 5.54 +/- 0.48 pA/pF; n = 6; P < 0.05). This effect was independent of the [Ca2+] of the pipette solution. Diamide, an alkylating agent that modifies protein sulfhydryl groups, also decreased the Ni(2+)-sensitive current (at + 60 mV: from 5.76 +/- 1.55 to 3.43 +/- 0.99 pA/pF; n = 6; P < 0.05). The stoichiometry (n) and partition coefficient (gamma) of the electrogenic Na(+)-Ca(2+)-exchange current seemed unchanged. Our results suggest that oxidant stress causes a direct or indirect sulfhydryl group-mediated decrease of the Na(+)-Ca2+ exchanger.

Animals↗
PubMed1994

Human T lymphotropic virus type I associated myelopathy and myasthenia gravis: a possible association?

We report the first known patient with human T lymphotropic virus type I (HTLV-I) associated myelopathy (HAM) and myasthenia gravis (MG). A 50-year-old woman developed fluctuating muscle weakness with easy fatigability, transient bilateral blepharoptosis and double vision. Spastic paraparesis complicated these symptoms. Neurological assessments and specific laboratory findings revealed that the patient had definite HAM and MG. By inference from decreasing serum anti-HTLV-I antibody titers after thymectomy, the presence of antigenicity for HTLV-I in the thymic reticular cells, and a high incidence of various coexistent autoimmune diseases in HAM or MG, we suggested the possibility that these two diseases were associated with each other and with HTLV-I infection.

Adult↗
PubMed1994

[Studies on antiulcer agents. I. The effects of various methanol and aqueous extracts of crude drugs on antiulcer activity].

The antiulcer activities of 59 methanol and aqueous extracts obtained from 59 crude drugs on the ethanol-HCl-induced ulceration in rats were investigated. Among them 15 extracts were selected and they were further examined for their effects on indomethacin-, aspirin- and the water-immersion stress-induced ulcer. From these results, the methanol extract of root of Iris germanica was found to, show potent antiulcer activities. The above methanol extract was separated into 3 portions by solvent extraction, and the ether soluble portion was fractionated into 5 fractions (1 to 5) by chromatography. Fractions 4 and 5 showed significant antiulcer activities. Fraction 4 was further purified and the obtained gamma-irigermanal exhibited a potent antiulcer activity. However, further investigations are required to understand the mechanism.

Animals↗
PubMed1994

[Studies on antiulcer agents. II. Synthesis and antiulcer activity of phenylpropanol derivatives].

It was found that gamma-irigermanal, obtained from the methanol extract of root of Iris germanica, exhibited a potent antiulcer activity. Therefore, this compound was selected as a lead-compound, and related compounds were synthesized and tested for antiulcer activities. It was found that (+/-) ethyl 2-[2-(3-hydroxypropyl)-4-oxocyclohexylidene]- propionate (1) had excellent antiulcer activities. Then phenylpropanol derivatives, obtained by changing from cyclohexane ring of 1 to benzene ring, were synthesized and tested for antiulcer activities in order to study structure activity relationships. As a result, (+/-) ethyl 2-[2-(3-hydroxypropyl)-4,5-dimethoxy-phenyl]propionate (2b) and (+/-) 3-[2-(3-hydroxypropyl)-4,5-dimethoxyphenyl]-2-butanone (5) were shown to have antiulcer activities.

1-Propanol↗
PubMed1994

Antioxidative effects of a processed grain food.

Antioxidant biofactor: AOB is a unique processed grain food. It is a yellow-green powder. It contains the following extracts: germ extracts, soybean, rice bran, tear grass, sesame, wheat, citron, green tea, green leaf extract, and malted rice. These materials were slowly roasted under a powdered oure at less than 60 degrees C and fermented with Aspergillus oryzae over 3 days to transform each ingredient into low molecular weight substances. These conditions were different by each material, environmental humidity and temperature. It probably contains a variety of substances having antioxidant activity including flavonoids, alpha-tocopherol, vitamin C, and tannins. We investigated its antioxidative properties using electron spin resonance (ESR) and autoxidation of rat brain homogenates. The superoxide, hydroxyl radical, and the stable free radical, diphenyl-p-picrylhydrazyl (DPPH) radical scavenging activity of AOB was investigated using ESR spectrometry. In an in vitro study, a suspension of AOB was added directly to a superoxide generating system (hypoxanthine-xanthine oxidase; HX/XO) and investigated using 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as a spin trapping agent. At final concentrations of 0.01, 0.05, and 0.1 mg/ml, AOB dose-dependent scavenging activity was observed as 0.103, 0.619, and 1.369 U/ml, respectively. A concentration of 1.0 mg/ml completely scavenged DMPO-OOH signals; 1.0 mg/ml of AOB inhibited the DMPO-OH signal generated by Fenton's reaction, but its inhibitory effect was not competitive, and was inhibition of the Fenton's reaction. 1.0, 3.0, and 5.0 mg/ml of AOB were significantly inhibited the DPPH radical. In an in vivo study, rats were fed AOB orally at doses of 1 or 5 g/day for 24 h or for 3 days and the superoxide scavenging activity was measured in plasma. With the administration of 1 g/day for 3 days, the superoxide scavenging activity was about 1.8 times that of the control group fed a basal diet; 1.5 times the control with 5 g/day for 1 day, and 2.6 times the control with 5 g/day for 3 days, all of which represented significant increases in superoxide scavenging activity. AOB strongly inhibited the autoxidation of rat brain homogenates in vitro in a dose-dependent manner. However, each ingredient before roast and fermentation little inhibited lipid peroxidation. Roasting and fermentation with A. oryzae way be important to transform each ingredient into low molecular weight substances. Therefore, it was suggested that AOB possesses strong antioxidant and free radical scavenging activities.

Animals↗