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Biomedical subjects

N Ishida

Publications and source records attributed to N Ishida.

At least 73 records · Page 4Linked to original sources
PubMed2000

Rhythmic expression of BMAL1 mRNA is altered in Clock mutant mice: differential regulation in the suprachiasmatic nucleus and peripheral tissues.

BMAL1 is a putative clock gene which encodes a basic helix-loop-helix (bHLH)-PAS transcription factor. To examine whether the CLOCK protein is required for the circadian expression of BMAL1 mRNA, in situ hybridization and Northern blot analysis were performed in the suprachiasmatic nucleus (SCN) and peripheral tissues of homozygous Clock mutant mice. In the SCN of Clock mutants, BMAL1 mRNA did not oscillate significantly but apparently expressed with low levels, while in wild-type mice the mRNA was robustly oscillated in a circadian manner. The peak-trough amplitudes of BMAL1 mRNA levels were 6.5-, 8.6-, and 6.7-fold in liver, heart, and kidney of wild-type mice, respectively. In Clock mutants, the amplitudes were extremely damped to 1.2-, 2.1-, and 1.4-fold, respectively. Furthermore, expressions of BMAL1 mRNA in the peripheral of Clock mutant mice were close to the peak level in wild-type mice, whereas mPer2 mRNA levels were severely blunted at trough values. Daily expression of albumin site D-binding protein (DBP), a clock controlled output gene (CCG), was also abolished at trough values by the Clock mutation in all tissues examined. These observations suggest that the circadian expression of BMAL1 mRNA is affected by the CLOCK-induced transcriptional feedback loop in the SCN and peripheral tissues in a different way and that the regulation mechanism appeared to be different from those in mPer2 and DBP expressions in vivo.

ARNTL Transcription Factors↗
PubMed2000

Characterization of audiogenic-like seizures in naive rats evoked by activation of AMPA and NMDA receptors in the inferior colliculus.

The role of glutamate receptors in the inferior colliculus (IC) in audiogenic and audiogenic-like seizures was investigated in adult rats with transient neonatal hypothyroidism by 0.02% propylthiouracil (PTU) treatment through mother's milk (PTU rats) and in naive rats treated intracisternally with N-methyl-d-aspartate (NMDA), alpha-amino-3-hydroxy-5-methyl-4-isoxazole-proprionic acid (AMPA), or cyclothiazide, an inhibitor of rapid AMPA receptor desensitization. All rats showed audiogenic or audiogenic-like seizures characterized by running fit (RF) and generalized tonic-clonic seizures (GTCS). While systemically administered MK-801 inhibited GTCS, intracisternally administered NBQX inhibited RF and GTCS in both audiogenic and audiogenic-like seizures. Auditory stimulation shortened the latency to GTCS induced by AMPA, but not NMDA, at a subclinical dose and further elongated the shortened duration of RF, but not GTCS, induced by MK-801 pretreatment. Furthermore, Northern blot analysis was used to evaluate the expression of the immediate-early gene c-fos in the IC following induction of audiogenic or audiogenic-like seizures. The significant induction of c-fos mRNA by audiogenic seizures in PTU rats or by AMPA- or cyclothiazide-induced seizures in naive rats was prominent in the IC. MK-801 suppressed c-fos mRNA expression in the IC induced by audiogenic seizures in PTU rats or by AMPA-induced seizures in naive rats. NBQX suppressed the expression of c-fos mRNA in the IC induced by AMPA-induced seizures but did not suppress c-fos mRNA in PTU rats or rats with cyclothiazide-induced seizures. Auditory stimuli failed to affect c-fos mRNA induction by AMPA. The present study suggests that audiogenic-like seizures can be reproduced by glutamate receptor agonists in which AMPA receptors are primarily linked to the initiation of audiogenic seizures (RF) while NMDA receptors presumably located within the IC are involved in the propagation of GTCS in audiogenic seizures.

Acoustic Stimulation↗
PubMed2000

The primary electron acceptor of green sulfur bacteria, bacteriochlorophyll 663, is chlorophyll a esterified with Delta2,6-phytadienol.

The primary electron acceptor of green sulfur bacteria, bacteriochlorophyll (BChl) 663, was isolated at high purity by an improved purification procedure from a crude reaction center complex, and the molecular structure was determined by fast atom bombardment mass spectroscopy (FAB-mass), (1)H- and (13)C-NMR spectrometry, double quantum filtered correlation spectroscopy (DQF-COSY), heteronuclear multiple-quantum coherence (HMQC) and heteronuclear multiple-bond correlation (HMBC) spectral measurements. BChl 663 was 2.0 mass units smaller than plant Chl a. The NMR spectra showed that the macrocycle was identical to that of Chl a. In the esterifying alcohol, a singlet P7(1) signal was observed at the high-field side of the singlet P3(1) signal in BChl 663, while a doublet peak of P7(1) overlapped that of P11(1) in Chl a. A signal of P7-proton, seen in Chl a, was lacking, and the P6-proton appeared as a triplet signal near the triplet P2-proton signal in BChl 663. These results indicate the presence in BChl 663 of a C=C double bond between P6 and P7 in addition to that between P2 and P3. The structure of BChl 663 was hence concluded to be Chl a esterified with 2,6-phytadienol instead of phytol. In addition to BChl 663, two molecules of the 13(2)-epimer of BChl a, BChl a', were found to be present per reaction center, which may constitute the primary electron donor.

Journal Article↗
PubMed2000

Light-induced phase-shifts in the circadian expression rhythm of mammalian period genes in the mouse heart.

To investigate the molecular mechanism that regulates circadian rhythms in mammalian peripheral tissues, we examined the phase shifts evoked by light exposure in the circadian mRNA expression rhythms of mammalian Period genes (mPer1, mPer2 and mPer3) and a clock-controlled gene Dbp, in the mouse heart, by Northern blot analysis. The light pulse did not induce any acute mRNA expression of mPer in the heart, but the pulse gave rise to phase shifts in the circadian mRNA rhythms. On the first day after the exposure, only mPer1 mRNA showed a phase shift, whereas obvious phase shifts were not observed in the rhythms of mPer2, mPer3 and Dbp mRNAs. On the second day, phase shifts occurred to a similar extent in the mRNA rhythms of all four genes examined. The rhythm of mPer1 mRNA shifted fastest among those of the three mPers. Therefore mPer1 seems to play an important role in phase resetting of mammalian peripheral oscillators. Immediate responses to light pulses in mRNA expression of mPers may not be required for phase shifting of peripheral circadian oscillators. Our findings suggest that mammals require more than one day to have peripheral oscillators entrained to a new daily schedule.

Animals↗
PubMed2000

Six different mutations of TGFBI (betaig-h3, keratoepithelin) gene found in Japanese corneal dystrophies.

PURPOSE: To investigate mutations of the human transforming growth factor beta-induced gene (TGFBI), transforming growth factor-beta-induced gene product (betaig-h3, keratoepithelin), in Japanese patients with Avellino corneal dystrophy (ACD), lattice corneal dystrophy (LCD), granular corneal dystrophy (GCD), and Reis-Bücklers corneal dystrophy (RBCD). METHODS: Genomic DNA was extracted from the peripheral blood of 75 patients and 7 unaffected relatives from 60 families with ACD, 34 patients and 8 unaffected relatives from 21 families with LCD, 4 patients and 4 unaffected relatives from 4 families with GCD, and 4 patients and an unaffected relative from 3 families with RBCD. Fifty normal volunteers served as controls. Exons 4, 11, and 12 of the TGFBI gene were amplified by polymerase chain reaction and were directly sequenced. RESULTS: Six different heterozygous missense mutations were detected in codons R124, L518, L527, and R555 of the TGFBI gene in the 117 patients from 88 families. A R124H mutation was detected in the patients with ACD. A R124C mutation was detected in the patients with LCD type 1 (LCD1), L518P was in atypical LCDI, and L527R in LCD with opacities deep in stroma. A R555W mutation was detected in the patients with GCD. A R555Q mutation was detected in the patients with RBCD. CONCLUSIONS: We conclude that codons R124 and R555 of the TGFBI gene are also hot spots in Japanese patients with ACD, LCD, GCD, and RBCD. Many Japanese patients with CD had ACD with R124H mutation. GCD with R555W mutation was rare.

Codon↗
PubMed2000

Phytogrowth-Inhibitory activities of beta-dolabrin and gamma-thujaplicin, hinokitiol-related compounds and constituents of Thujopsis dolabrata Sieb. et Zucc. var hondai Makino.

Beta-dolabrin and gamma-thujaplicin isolated from Thujopsis dolabrata Sieb. et Zucc. var hondai Makino, like hinokitiol, showed strong phytogrowth-inhibitory activities, and their growth-inhibitory activities were as high as that of sodium 2,4-dichlorophenoxyacetate used as a positive control. In particular, the phytogrowth-inhibitory activity of gamma-thujaplicin was strong and it completely inhibited the germination of this seed of Brassica campestris L. subsp. rapa Hook f. et Anders at the concentration of 30 ppm. Both compounds exhibited inhibitory activities on B. campestris L. subsp. rapa Hook f. et Anders and Sesamum indicum Linne, even at the low concentration of 10 ppm. At 7 d after treatment with beta-dolabrin and gamma-thujaplicin, the amount of chlorophyll in the cotyledons of B. campestris L. subsp. rapa Hook f. et Anders treated with both compounds was greatly decreased as compared with the control. The findings indicate that the phytogrowth-inhibitory action might be a common biological activity of hinokitiol-related compounds, suggesting that at least a part of their phytogrowth-inhibitory actions seems to be related to a decrease in chlorophyll content.

Brassica↗
PubMed2000

Antifungal activity of Hinokitiol-related compounds on wood-rotting fungi and their insecticidal activities.

Hinokitiol (beta-thujaplicin), beta-dolabrin and gamma-thujaplicin isolated from Thujopsis dolabrata SIEB. et ZUCC var hondai MAKINO showed antifungal activities against all of the wood-rotting fungi examined. The antifungal activity of three compounds on Daedalea dickinsii IFO-4979 was especially strong, their minimum inhibitory concentration (MIC) values being 0.2 microg/ml. Their antifungal activities on D. dickinsii IFO-4979 were as high as that of amphotericin B used as a positive control. Three compounds had strong insecticidal activities on Tyrophagus putrescentiae [50%-lethal concentration (LC50 : g/m2) 0.25 in hinokitiol, 0.02 in beta-dolabrin and gamma-thujaplicin. Their insecticidal activities were higher than that of N,N-diethyl-m-toluamide (DEET, LC50 : 1.46 g/m2) used as a positive control. Three compounds also showed strong insecticidal activity on Coptotermes formosanus [LC50 (g/m2) 0.07 in hinokitiol, 0.05 in beta-dolabrin and gamma-thujaplicin], although their insecticidal activities were much lower than that of commercial chloropyrifos (LC50 : 0.00016 g/m2).

Antifungal Agents↗
PubMed2000

Identification and characterization of a potent antibacterial agent, NH125 against drug-resistant bacteria.

New imidazole compounds were synthesized to develop a novel and effective antibacterial agent (1-benzyl-3-cetyl-2-methylimidazolium iodide, NH125). In vitro experiments demonstrated that NH125 effectively inhibited a number of different histidine protein kinases. Furthermore, oxacillin-resistant Staphylococcus aureus (ORSA), vancomycin-resistant Enterococcus faecalis (VRE), penicillin-resistant Streptococcus pneumoniae (PRS), and other Gram-positive and Gram-negative bacteria were found to be very sensitive to NH125.

Anti-Bacterial Agents↗
PubMed2000

Sex determination by simultaneous amplification of equine SRY and amelogenin genes.

A quick method for sex determination of horses was developed. Simultaneous amplification of the equine sex-determining region of the Y chromosome gene (SRY) and amelogenin gene (AMEL) accomplished the determination of the presence of both the Y chromosome and SRY gene. In agarose gel electrophoresis, a normal stallion showed 1 SRY band and 3 AMEL (AMELX, AMELY, and AMELX/AMELY heteroduplex) bands, and a normal mare showed a single AMELX band. In XY-mares, 3 AMEL bands were detected as in a normal stallion, but no SRY band. The present method enables a quick diagnosis for XY-mare prior to cytogenetic analysis.

Amelogenin↗
PubMed2000

Molecular cloning of equine chromogranin A and its expression in endocrine and exocrine tissues.

Chromogranin A (CGA) is a member of a family of highly acidic proteins co-stored and co-released with catecholamines in the adrenal medullary cells as well as in other neurons and paraneurons. The nucleotide sequence encoding equine CGA was determined using RT-PCR and rapid amplification of complementary DNA (cDNA) ends (RACE) techniques. A total 1,828 bp of the nucleotide sequence reveals that equine CGA is a 448-residue protein preceded by an 18-residue signal peptide. Comparison of the amino acid sequence of equine CGA with those of human, porcine, bovine, mouse, rat and frog CGA showed high conservation at the NH2-terminal 1-77 amino acids regions (94.8%, 93.5%, 92.2%, 81.8%, 83.1% and 66.2%, respectively) and COOH-terminal 314-430 amino acids regions (90.6%, 81.4%, 90.6%, 80.5%, 83.3% and 39.0%, respectively), as well as a potential dibasic cleavage site, whereas the middle portion showed marked sequence variation (52.5%, 49.1%, 38.9%, 26.6%, 27.9% and 6.2%, respectively). Northern blot analysis and RT-PCR elucidated the tissue distribution of equine CGA mRNA. Its expression was confirmed not only in the adrenal medullary cells but also in other organs (cerebrum, cerebellum, pituitary gland, spinal cord, liver, thyroid gland, striated muscle, lung, spleen, kidney, parotid gland and sublingual gland). Further, in adrenal chromaffin cells and pituitary cells of the anterior-intermediate lobe, the expression was confirmed by in situ hybridization with anti-sense CGA cRNA probe.

Amino Acid Sequence↗
PubMed2000

[Clinical study of aortic root replacement].

From 1990 to 1999, 19 patients underwent aortic root replacement. Annulo-aortic ectasia was observed in 14 patients, aortic dissection in 4, and aortitis in 1. Mean aortic cross-clamp times and cardiopulmonary bypass times were 163 +/- 44 and 247 +/- 99 min, respectively. Concomitant procedures were coronary artery bypass grafting in 3 patients, aortic arch replacement in 1 and aortic arch replacement and elephant trunk method in 2. There were two hospital deaths due to cardiac failure. There was one late death because of pharyngeal cancer 1.7 years after the operation. Seventeen survivors were followed for a mean duration of 4.4 years (0.6-9.3 years). There were no complications during this period. In conclusion, good results were obtained by modified Bentall operation.

Adult↗
PubMed2000

Leakage of aquaporin 5 in the tear of dacryoadenitis mice.

PURPOSE: The objective of this study was to investigate whether leakage of aquaporin 5 (AQP5) in tear is associated with damage of lacrimal glands (LGs) in dacryoadenitis models. METHODS: Female MRL/lpr (24-week-old), male NOD/Shi Jci (5-, 8-, and 10-week-old), female NFS/s-TX (10-week-old), and lipopolysaccharide (LPS)-induced dacryoadenitis model mice were used. Tear fluid was collected by a cotton thread. Tear proteins in the thread were dissolved in sodium dodecyl sulfate buffer, and AQP5 proteins were analyzed by the Western blot technique using anti-AQP5 antibody. LGs were prepared for hematoxylin and eosin staining or immunostaining of AQP5. RESULTS: In MRL/lpr, NFS/s-TX, 8- and 10-week-old NOD/Shi Jci mice, AQP5 protein was detected in the tear by Western blot analysis. Inflammatory lymphocyte infiltrations were observed in LGs of these dacryoadenitis model mice. In contrast, AQP5 leakage and damage of LG were not observed in normal mice. In 5-week-old NOD/Shi Jci mice, infiltration was not seen in LG, and AQP5 leakage was not detected in the tear. In LPS-induced dacryoadenitis model mice, either tissue destruction with inflammation in LG or AQP5 leakage in the tear was observed. AQP5 in the tear and tissue inflammation in LGs was not found in control mice. These results indicate that AQP5 is leaked in tears when LGs are damaged by dacryoadenitis. CONCLUSIONS: Leakage of AQP5 in the tear was found to be related to LG damage. This finding suggests that detection of AQP5 in tear is useful for specific diagnosis of LG disorders with tissue destruction.

Animals↗
PubMed2000

[Sudden bilateral hearing loss with vertigo due to vertebral artery occlusion].

We report a case of sudden bilateral hearing loss associated with an occlusion of the right vertebral artery. A 66-year-old man was admitted to hospital suffering from sudden onset vertigo, deafness, and vomiting. He could not walk due to truncal ataxia. There was positional nystagmus to the right; spontaneous and gaze-evoked nystagmus were absent. He had no facial nerve palsy, dysarthria, pyramidal tract signs, limb ataxia, and sensory impairment. Pure tone audiometry demonstrated a profound sensorineural deafness of both ears. A tentative diagnosis of sudden deafness was made. He was treated with intravenous infusion of corticosteroid; hearing loss of the left ear slightly improved. Cranial MR imaging demonstrated fresh small infarcts in the right cerebellar tonsil, the left cerebellar medulla, and the left middle cerebellar peduncle. MR angiography demonstrated an occlusion of the right vertebral artery. It is possible that reduced perfusion of the anterior inferior cerebellar arteries and internal auditory arteries on both sides resulted in multiple "border zone" infarcts and damage to the inner ear. Clinicians should be aware of the possibility of vertebrobasilar occlusive disease in case of sudden bilateral hearing impairment, even when brainstem or cerebellar signs are absent.

Aged↗
PubMed1999

Effects of Hydrophobizing Methods of Surfaces on the Interaction in Aqueous Solutions.

The hydrophobic interaction between the surfaces hydrophobized by the adsorption of STAC in a STAC solution (system I) and the interaction between the surfaces hydrophobized by the reaction with OTS in water (system II) were investigated using an atomic force microscope, and their difference was compared. Clear differences of the interaction between systems I and II were found with respect to the force curves and the morphology of the surfactants adsorbed on the surfaces. It is postulated that the hydrophobic interaction for system II is attributable to the cavity bridging between the surfaces, but that for system I it is originated from a different mechanism. It is also implied that the existence of the surfactants in the bulk will play an important role for the hydrophobic interaction. Copyright 1999 Academic Press.

Journal Article↗