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Biomedical subjects

K Nishi

Publications and source records attributed to K Nishi.

At least 37 records · Page 2Linked to original sources
PubMed2001

Effect of round-edged acrylic intraocular lenses on preventing posterior capsule opacification.

PURPOSE: To clarify the extent to which the adhesiveness of an acrylic material influences the formation of posterior capsule opacification (PCO). SETTING: Jinshikai Medical Foundation, Nishi Eye Hospital, Osaka, Japan. METHODS: Two types of AcrySof(R) intraocular lenses (IOLs) were prepared: round edged and tumbled. The AcrySof with round edges was implanted in 1 eye in a group of 4 rabbits and the tumbled IOL, in 1 eye in a group of 5 rabbits. In both groups, the contralateral eye received a conventional AcrySof with sharp optic edges. A histopathological examination was performed 3 weeks after surgery. RESULTS: With the round-edged AcrySof IOL, no capsular bend formed at the optic edge and abundant lens epithelial cells (LECs) migrated posteriorly. With the sharp-edged AcrySof lens, a sharp capsular bend formed and LEC migration was significantly inhibited. In eyes with a tumbled IOL, a capsular bend was created, but it was less marked than that created by the sharp-edged lens and there was slightly more LEC migration posteriorly. CONCLUSIONS: The AcrySof IOL lost its preventive effect on PCO when the optic was rounded. The effect of the AcrySof lens in preventing PCO is mainly a result of its rectangular, sharp-edged optic design. The acrylic material may play a complementary role by helping create a sharp capsular bend. Capsular bend formation is the key to the PCO preventive effect of an IOL.

Acrylic Resins↗
PubMed2001

Capsular bending ring to prevent posterior capsule opacification: 2 year follow-up.

PURPOSE: To evaluate the preventive effect of a capsular bending ring on anterior and posterior capsule (PCO) opacification in a 2 year clinical study. SETTING: Jinshikai Medical Foundation, Nishi Eye Hospital, Osaka, Japan. METHODS: This study comprised 60 patients with senile cataract (35 women, 25 men) with a mean age of 69 years. An open poly(methyl methacrylate) capsular bending ring with a truncated edge profile designed to create a sharp bend in the equatorial capsule was implanted in 1 eye of patients with a hydroxyethyl methacrylate intraocular lens (IOL). The contralateral eye, which acted as a control, received an IOL but no ring. Patients were examined 6 months (n = 52), 1 year (n = 48), and 2 years (n = 42) postoperatively. Anterior capsule opacification was determined by slitlamp evaluation. Anterior capsule shrinkage (area within the capsulorhexis) and PCO were evaluated and scored using a computer software package for image analysis. Posterior capsule opacification was also measured by the rate of neodymium:YAG (Nd:YAG) capsulotomies. RESULTS: Anterior capsule opacification and shrinkage were significantly less in eyes with the ring. The mean PCO score was 0.235 +/- 0.215 (SD), 0.287 +/- 0.200, and 0.398 +/- 0.248 with the ring and 0.530 +/- 0.190, 0.670 +/- 0.225, and 1.111 +/- 0.298 without the ring at 6 months, 1 year, and 2 years, respectively (P <.01 at each follow-up). An Nd:YAG laser capsulotomy was performed in 4 eyes with and 17 eyes without the ring after 2 years (P <.01). CONCLUSIONS: The capsular bending ring significantly reduced anterior capsule fibrosis and shrinkage as well as PCO. The ring may be useful in patients who are at high risk of developing eye complications from capsule opacification that require Nd:YAG laser capsulotomy, in those expected to have vitreoretinal surgery and photocoagulation, and in cases of pediatric cataract.

Aged↗
PubMed2001

Selective expression of erg isoforms in human endothelial cells.

Erg and Fli-1 are closely related members of the ets family of transcription factors. There are at least five human Erg isoforms (Erg-1, Erg-2, Erg-3/p55(Erg), p49(Erg) and p38(Erg)) produced through differential mRNA splicing and alternative use of translational start codons. However, relatively little is known about the expression or function of these isoforms in vitro or their distribution in vivo. We used RT-PCR to screen a panel of primary and established human cell lines for erg and fli-1 consensus sequences. Whilst fli-1 was expressed in several human cell types, erg was detected mainly in endothelial cells. To identify which erg isoforms are expressed in endothelial cells we used RT-PCR, Northern blotting and 5'-RACE. Erg-3/p55(Erg) and p38(Erg)/p38(Erg)-like transcripts were detected in both microvascular and large vessel endothelial cells affinity-purified from different vascular beds. Moreover, these erg isoforms were present in both freshly isolated, and confluent endothelial cells following several passages in culture, indicating that endothelial erg expression in vitro may be broadly representative of that in vivo. The selective expression of the Erg-3/p55(Erg) and p38(Erg)/p38(Erg)-like isoforms in endothelial cells indicates their involvement in the regulation of endothelial-restricted genes.

Base Sequence↗
PubMed2001

The properties of ryanodine-sensitive Ca(2+) release in mouse gastric smooth muscle cells.

1. Under voltage-clamped conditions, gastric smooth muscle cells of BALB/c mice developed spontaneous (STOCs) and caffeine- (I(CAF)) and carbachol-induced (I(CCh)) transient outward currents. 2. In fura-2 microscopic measurements of intracellular Ca(2+) concentration ([Ca(2+)](i)), caffeine and carbachol (CCh) provoked similar transient [Ca(2+)](i) elevations. 3. Both I(CCh) and CCh-induced [Ca(2+)](i) elevation of single smooth muscle cells occurred in an 'all-or-nothing' fashion in contrast to the reproducible caffeine responses. 4. On the basis of the suppression of STOCs and I(CAF) by nicardipine, tetraethylammonium and iberiotoxin, but not by charybdotoxin nor apamin, it was suggested that both currents were generated by large conductance type Ca(2+)-activated K(+) channels. 5. In measurements of isometric tension, caffeine produced relaxation of gastric smooth muscle strips in a concentration-dependent manner (0.1 -- 3 mM). The concentration-dependent relaxation with caffeine was mimicked by dibutyryl cyclic AMP which produced potentiation of contraction triggered by 50 mM KCL. 6. At caffeine concentrations >3 mM, a transient contraction followed by relaxation was provoked as the quasi maximal response to caffeine. In the quasi maximal response, caffeine acted as a potent relaxant in smooth muscle strips precontracted with 50 mM KCl or 3 microM CCh. 7. The relaxation with caffeine was significantly accelerated in those strips precontracted with KCl or CCh. All these results suggest that ryanodine-sensitive Ca(2+) release, which is triggered by caffeine, is an important modifier of Ca(2+) homeostasis in the cytoplasm and the contractility of gastric smooth muscle cells of mice.

Animals↗
PubMed2001

Near-field spectroscopy of single quantum dots at room temperature.

The observation of photoluminescence spectra of self-assembled single InGaAs quantum dots at room temperature was performed under weak excitation conditions using a near-field scanning optical microscope. Operation in illumination-collection mode with a highly sensitive double-tapered optical fibre probe enabled detection of weak photoluminescence signals at room temperature with high efficiency and high spatial resolution. Each single quantum dot was imaged with a spatial resolution of about 250 nm, which corresponded to a quarter of the wavelength of the photoluminescence from quantum dots. The photoluminescence yields of individual quantum dots were widely distributed and were found to decrease with photoluminescence energy. This result serves as a clue to be pursued for better understanding of the thermal excitation of the carrier from confined states in quantum dots.

Journal Article↗
PubMed2001

Inhibition of lens epithelial cells by Fas-specific antibody activating Fas-Fas ligand system.

PURPOSE: To detect cell specific apoptosis factors, Fas and Fas ligand, and the common intracellular apoptosis modulators, interleukin-1 beta converting enzyme (ICE)-like protease (caspase 1), Bcl-2, Bcl-xL and Bax in lens epithelial cells (LEC) of human cataracts. To study the effects of Fas-stimulating monoclonal antibody on inhibition of LEC proliferation. METHODS: Reverse-transcriptase-polymerase chain reaction (RT-PCR) was used to detect Fas, Fas ligand, caspase 1, Bcl-2, Bcl-xL and Bax, after cDNA was synthesized from the total RNA isolated from human cataractous LEC obtained by capsulotomy during cataract surgery. Fas-stimulating monoclonal antibody was added at the concentrations of 10, 30, 100, 300 and 1000 ng/ml to the incubation medium of human cataractous LEC; and the specimens were incubated for 24 h at 37 degrees C with 5% CO(2) circulation and 100% humidity. The specimens were then stained with Hoechst 33342, and the number of apoptotic cells was counted. RESULTS: Fas, caspase 1, Bcl-2, Bcl-xL and Bax mRNA were detected by RT-PCR. Fas ligand mRNA was not detected by RT-PCR. At each concentration, Fas-stimulating monoclonal antibody significantly inhibited LEC proliferation. CONCLUSIONS: Human cataractous LEC expressed mRNA of Fas and various modulators of apoptosis pathways. Fas-stimulating monoclonal antibody may have the potential to prevent posterior capsule opacification after cataract surgery by inhibiting LEC proliferation.

Aged↗
PubMed2001

Noradrenaline receptor-mediated potentiation of caffeine-induced Ca( 2+)-activated K(+) currents in bovine ciliary muscle cells.

PURPOSE: Adrenoceptor-mediated modulation of a caffeine (CAF)-induced [Ca(2+)](i) elevation and resulting Ca(2+)-activated K(+) current (I(CAF)) in bovine ciliary muscle (CM) cells were investigated. METHODS: The nystatin-perforated patch clamp technique for the measurement of membrane currents and a microscope based fura-2 fluorescence imaging of [Ca(2+)](i) were applied to CM cells freshly dissociated with collagenase and identified with smooth muscle-specific alpha-isoactin. RESULTS: Under voltage-clamped conditions, noradrenaline (NA) potentiated I(CAF) in a NA concentration-dependent manner without producing current responses to NA when NA was applied alone. NA-induced potentiation of I(CAF) occurred within 20 sec after the application of NA, while the NA-potentiated I(CAF) gradually recovered to the control level within 30 min after removal of NA. Despite the little current response to NA applied alone, NA elicited a [Ca(2+)](i) elevation in a manner similar to that induced by CAF although the NA-induced [Ca(2+ )](i) elevation was smaller than the CAF-induced [Ca(2+ )](i) elevation. In contrast to the significant potentiation of I(CAF) with NA, NA produced little potentiation of the CAF-induced [Ca(2+)](i) elevation. The NA-induced potentiation of I( CAF) was antagonized by an alpha(1) adrenoceptor antagonist, prazosin. Neither clonidine nor isoproterenol had an effect on I(CAF), suggesting that alpha(2) and beta adrenoceptor are not involved in the response to NA. CONCLUSIONS: These results suggest that NA potentiates I( CAF) via alpha(1) adrenoceptor activation and that the NA-induced potentiation occurs at Ca(2+)-activated K(+) channels but not CAF-induced Ca(2+) releasing sites.

Adrenergic alpha-Antagonists↗
PubMed2001

Purification, molecular cloning, and immunohistochemical localization of dipeptidyl peptidase II from the rat kidney and its identity with quiescent cell proline dipeptidase.

We purified dipeptidyl peptidase II (DPP II) to homogeneity from rat kidney and determined its physicochemical properties, including its molecular weight, substrate specificity, and partial amino acid sequence. Furthermore, we screened a rat kidney cDNA library, isolated the DPP II cDNA and determined its structure. The cDNA was composed of 1,720 base pairs of nucleotides, and 500 amino acid residues were predicted from the coding region of cDNA. Human quiescent cell proline dipeptidase (QPP) cloned from T-cells is a 58-kDa glycoprotein existing as a homodimer formed with a leucine zipper motif. The levels of amino acid homology were 92.8% (rat DPP II vs. mouse QPP) and 78.9% (rat DPP II vs. human QPP), while those of nucleotide homology were 93.5% (rat DPP II vs. mouse QPP) and 79.4% (rat DPP II vs. human QPP). The predicted amino acid sequences of rat DPP II and human and mouse QPP possess eight cysteine residues and a leucine zipper motif at the same positions. The purified DPP II showed similar substrate specificity and optimal pH to those of QPP. Consequently, it was thought that DPP II is identical to QPP. Northern blot analysis with rat DPP II cDNA revealed prominent expression of DPP II mRNA in the kidney, and the order for expression was kidney >> testis > or = heart > brain > or = lung > spleen > skeletal muscle > or = liver. In parallel with Northern blot analysis, the DPP II antigen was detected by immunohistochemical staining in the cytosol of epithelial cells in the kidney, testis, uterus, and cerebrum.

Amino Acid Sequence↗
PubMed2001

Mutation of an arginine biosynthesis gene causes reduced pathogenicity in Fusarium oxysporum f. sp. melonis.

Restriction enzyme-mediated integration (REMI) mutagenesis was used to tag genes required for pathogenicity of Fusarium oxysporum f. sp. melonis. Of the 1,129 REMI transformants tested, 13 showed reduced pathogenicity on susceptible melon cultivars. One of the mutants, FMMP95-1, was an arginine auxotroph. Structural analysis of the tagged site in FMMP95-1 identified a gene, designated ARG1, which possibly encodes argininosuccinate lyase, catalyzing the last step for arginine biosynthesis. Complementation of FMMP95-1 with the ARG1 gene caused a recovery in pathogenicity, indicating that arginine auxotrophic mutation causes reduced pathogenicity in this pathogen.

Arginine↗
PubMed2001

Carotid endarterectomy with external shunt: a new device and indication for use: technical note.

OBJECTIVE: We designed a new external shunt system and evaluated its indications and efficacy in patients undergoing carotid endarterectomy (CEA). METHODS: In 8 of 332 CEA procedures, external shunts were placed between the common carotid artery and the internal carotid artery (ICA). This procedure was implemented for one of two indications: 1) a change in electroencephalographic and/or somatosensory evoked potential readings immediately after ICA occlusion, or 2) elongation of the ICA made safe insertion of an internal shunt impossible. In addition, a shunt was placed between the common carotid artery and the external carotid artery to establish collateral circulation from the external carotid artery to the intracranial circulation, which is essential during ICA occlusion. RESULTS: All external shunts were functional, and electroencephalography and somatosensory evoked potentials demonstrated no significant abnormalities during the CEAs. All patients awoke from surgery without manifestation of new neurological deficits. CONCLUSION: Our new external shunt device proved safe and efficacious in cases that did not permit the placement of an internal shunt.

Aged↗
PubMed2001

[Effectiveness of influenza vaccine in health-care workers].

We examined the effectiveness of trivalent influenza vaccine in reducing illness, absenteeism, and health care use among health-care workers (HCW) of Ishikawa Prefectural Central Hospital from December 1999 through March 2000. In recipients of vaccine (n = 132), the numbers of febrile illness, severe illness, febrile upper respiratory tract illness were significantly reduced compared with HCW without vaccination (n = 595). Use of prescription antibiotics and over-the-counter medications was also reduced. Influenza vaccine also reduced the reported days of work absence. These data support a policy of annual influenza vaccination of HCW.

Adult↗
PubMed2001

Effects of consonantal context on perceptual assimilation of American English vowels by Japanese listeners.

This study investigated the extent to which adult Japanese listeners' perceived phonetic similarity of American English (AE) and Japanese (J) vowels varied with consonantal context. Four AE speakers produced multiple instances of the 11 AE vowels in six syllabic contexts /b-b, b-p, d-d, d-t, g-g, g-k/ embedded in a short carrier sentence. Twenty-four native speakers of Japanese were asked to categorize each vowel utterance as most similar to one of 18 Japanese categories [five one-mora vowels, five two-mora vowels, plus/ei, ou/ and one-mora and two-mora vowels in palatalized consonant CV syllables, C(j)a(a), C(j)u(u), C(j)o(o)]. They then rated the "category goodness" of the AE vowel to the selected Japanese category on a seven-point scale. None of the 11 AE vowels was assimilated unanimously to a single J response category in all context/speaker conditions; consistency in selecting a single response category ranged from 77% for /eI/ to only 32% for /ae/. Median ratings of category goodness for modal response categories were somewhat restricted overall, ranging from 5 to 3. Results indicated that temporal assimilation patterns (judged similarity to one-mora versus two-mora Japanese categories) differed as a function of the voicing of the final consonant, especially for the AE vowels, /see text/. Patterns of spectral assimilation (judged similarity to the five J vowel qualities) of /see text/ also varied systematically with consonantal context and speakers. On the basis of these results, it was predicted that relative difficulty in the identification and discrimination of AE vowels by Japanese speakers would vary significantly as a function of the contexts in which they were produced and presented.

Adolescent↗
PubMed2001

Rat tripeptidyl peptidase I: molecular cloning, functional expression, tissue localization and enzymatic characterization.

We purified tripeptidyl peptidase I (TPP I) to homogeneity from a rat kidney lysosomal fraction and determined its physicochemical properties, including its molecular weight, substrate specificity and partial amino acid sequence. The molecular weight of the enzyme was calculated to be 280,000 and 290,000 by non-denaturing PAGE and gel filtration, respectively, and to be 43 000 and 46 000 on SDS-PAGE in the absence and presence of beta-ME, respectively. These findings suggest that the enzyme is composed of six identical subunits. The Km, Vmax, kcat and kcat/Km values of TPP I at optimal pH (pH 4.0) were 680 microM, 3.7 micromol x mg(-1) x min(-1), 33.1 s(-1) and 4.87 x 10(4) s(-1) x M(-1) for Ala-Ala-Phe-MCA, respectively. TPP I was significantly inhibited by PCMBS and HgCl2, and moderately by DFP. These findings also suggest that TPP I is an exotype serine peptidase that is regulated by SH reagent. TPP I released the tripeptide Arg-Val-Tyr from angiotensin III more rapidly than from Ala-Ala-Phe-MCA, and also released Gly-Asn-Leu from neuromedin B with the same velocity as from Ala-Ala-Phe-MCA. Angiotensin III and neuromedin B have recently been found to be good natural substrates for lysosomal TPP I. Furthermore, we determined the rat liver cDNA structure and deduced the amino acid sequence. The cDNA, designated as lambdaRTI-1, is composed of 2485 bp and encodes 563 amino acids in the coding region. By Northern blot analysis, the order for TPP I mRNA expression was kidney > or = liver > heart > brain > lung > spleen >> skeletal muscle and testis. In parallel experiments, the TPP I antigen was detected in various rat tissues by immunohistochemical staining.

Amino Acid Sequence↗
PubMed2001

Functional, metabolic, and histological changes of vascular tissues after warm ischemia.

We examined functional, metabolic, and histological changes in the aortic tissue of rats after the period of warm ischemia ranging from 0 to 24 hours to determine the window of time in which grafts can be optimally viable for harvest. Sixty aortas from Brown Norway rats obtained after warm ischemia were used and changes in contraction, endothelial-dependent or -independent vasodilatation, cell viability, and histology were examined. Maximal contraction induced by norepinephrine and potassium chloride decreased time-dependently after exposure to warm ischemia. The warm ischemic period when 50% of the maximal contractile response of freshly isolated arteries was preserved, ranged from 6 to 8 hours. Maximal endothelium-dependent relaxation induced by acetylcholine decreased along with the time of warm ischemia. Endothelium-independent relaxation induced by sodium nitroprusside and forskolin was unaltered for up to 9 hours. Cell viability gradually decreased, and a significant negative correlation was found between warm ischemic period (T: hours) and cell viability (V: %) (V=101.9-2.35T; r(2)=0.96; p<0.0001). Cell viability was greater than 70% within 12 hours postmortem. Histologically, after 9-hour-warm ischemia irreversible changes were detected. Results suggest that the period of warm ischemia for up to 6 hours would be acceptable for preservation of tissue viability.

Analysis of Variance↗
PubMed2001

[A case of relapsing polychondritis monitored by daily peak flow measurement].

A 55-year-old man was admitted to our hospital with dyspnea and stridor. At presentation, he also had a low grade fever, arthralgia and nasal obstruction. His chest roentgenogram showed diffuse tracheal narrowing, and chest CT revealed a thickened tracheal wall and fractured cricoid and thyroid cartilages. A diagnosis of relapsing polychondritis was made on the basis of his symptoms and in accordance with Damiani's criteria and CT findings. Daily peak flow (PEF) monitoring was carried out to assess the disease condition of the trachea. Methylprednisolone pulse therapy was started, and was followed by oral prednisolone, which improved his condition immediately, but reduction of oral prednisolone led to recurrence. The clinical course was clearly evaluated by PEF monitoring, but the change was undetectable on chest CT. Dapson, cyclophosphamide, and inhaled steroid were administered with oral prednisolone and the patient's condition has since been fair and stable. PEF monitoring may be useful for the early detection of recurrence in cases of relapsing polychondritis.

Humans↗
PubMed2000

Molecular cloning and immunohistochemical localization of rat dipeptidyl peptidase III.

Dipeptidyl peptidase III (DPP III) was purified to homogeneity from rat liver cytosol. The calculated molecular weight of the purified enzyme was 82845.6 according to TOF-MS, and 82000 on non-denatured PAGE and 82000 on SDS-PAGE in the absence or presence of beta-ME. These findings suggest that the enzyme assumes a monomeric form in rat liver cytosol. The enzyme rapidly hydrolyzed the substrate Arg-Arg-MCA and moderately hydrolyzed Ala-Arg-MCA in a pH range of 7. 5 to 9.5. The K(in), K(cat) and K(cat)/K(m) values of DPP III at optimal pH (pH 8.5) were 290 microM, 18.0 s(-1) and 6.21x10(4) s(-1)M(-1) for Arg-Arg-MCA and 125 microM, 4.53 s(-1) and 3.62x10(4) s(-1)M(-1) for Ala-Arg-MCA, respectively. DPP III was potently inhibited by EDTA, 1,10-phenanthroline, DFP, PCMBS, NEM, beta-ME and iodoacetamide. Furthermore, we screened a rat liver cDNA library using affinity-purified anti-rat DPP III rabbit IgG, and we determined the cDNA structure and deduced the amino acid sequence. The cDNA designated as lambdaRDIII-11 is composed of 2640 bp of nucleotides in length and encodes 738 amino acids in the coding region. Although the enzyme has a novel zinc-binding motif, HEXXXH in structure, DPP III is thought to belong to family 1 in clan MA in the metalloprotease kingdom. These findings suggest that DPP III is a metalloprotease that is probably regulated by SH modification. The DPP III antigen was extensively detected in the cytosol of various rat tissues by the immunohistochemical examination of the protein.

Amino Acid Sequence↗
PubMed2000

Lectin-histochemical detection of degenerative glycoconjugate deposits in human brain.

Several lectins were used to study the localization of glycoconjugates in brain of elderly people and patients with Alzheimer type dementia (ATD) and Down's syndrome (DS). Five kinds of degenerated or deposited materials stained clearly by lectins specific to GalNAC, Gal, Fuc, and/or Man were recognized much in ATD and DS, less in elderly peoples, in addition to the binding of the lectins to neurons. (i) Round shape deposits called corpora amylacea (CA) which consisted of various sizes of round material, existed mainly on the surface of cerebral cortex and some in white matter of the brain. They were colored by Alcian blue (AB), Aldehyde fucsin (AF) and periodic acid shiff (PAS) and weakly by Hematoxylin (H), but not by Eosin (B). They showed clear reactivity with lectins specific to GalNAC, Gal, Fuc and Gal-GalNAC. (ii) Amorphous and variform amyloid deposits existed around blood vessels in the white matter were stained by thioflavin and lectins specific to GalNAC, Gal and Fuc, but not with Man specific lectins and PAS, AB, AF and HE. (iii) Another kind of amyloid deposits which showed a similar characteristic to the previous one and were recognized mainly in white matter and independent blood vessels. These deposits were stained by thioflavin but not by PAS, AB, AF and HE and showed good reactivity with lectins specific to GalNAC, Gal, Fuc, Gal-GalNAC, Gal-GIcNAc and Man. The reactivity with lectins specific to Gal, Fuc, and Man was seen in senile plaques (iv) and neurofibrillary tangles (v). Although at present we are unable to explain the origin of these deposits, it is clear from this study that the glycoconjugates form an integral part of the degeneration in the brain. The lectin staining with GS-I is useful in the forensic pathology to diagnose brain disorders at postmortem examination, since these lectin were able to detect five types of degeneration changes and/or deposits.

Adult↗