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Biomedical subjects

S Uchida

Publications and source records attributed to S Uchida.

At least 253 records · Page 14Linked to original sources
PubMed1995

Isolation of human aquaporin 3 gene.

Human aquaporin 3 (AQP3) gene was isolated, and its structural organization was characterized. The gene appeared to exist as a single copy in the human genome and to comprise six exons distributing over 7 kilobases. The sizes of the exons are 171, 127, 138, 119, 218, and 1035 base pairs, and those of introns are approximately 3530, 300, 350, 330, and 90 base pairs, respectively. The initiation site of transcription was identified to locate 64 base pairs upstream of the first ATG codon by primer extension analysis and ribonuclease protection assay. The 5'-flanking region has a TATA box, two Sp1 sequences, and some consensus sequences including AP2 sites. With luciferase assay, the 5'-flanking region was demonstrated to have a promoter activity, which is up-regulated 4-fold by phorbol ester. These findings about the genomic clone of human AQP3 will contribute to elucidate the molecular mechanism of transcriptional regulation of AQP3.

Amino Acid Sequence↗
PubMed1995

The canine betaine gamma-amino-n-butyric acid transporter gene: diverse mRNA isoforms are regulated by hypertonicity and are expressed in a tissue-specific manner.

The Na(+)- and Cl(-)-coupled betaine transporter, designated BGT1, a member of the neurotransmitter transporter gene family, is responsible for accumulation of betaine in hypertonic Madin-Darby canine kidney (MDCK) cells and presumably in the hypertonic renal medulla. The canine gene for the betaine gamma-amino-n-butyric acid transporter has been cloned and analyzed. The gene extends over 28 kb and consists of 18 exons. The 5' end of the gene has three alternative first exons (1A, 1B, and 1C+D). Analysis of BGT1 mRNA revealed that there is considerable divergence in the 5' untranslated sequence resulting from three different 5' end motifs (A, B, and C) followed by an alternative motif (D) as well as two internal acceptor sites for splicing. Eight kinds of BGT1 mRNA were classified into three types (A, B, and C) according to the 5' end sequence. Northern blot analysis using probes specific for the A, B, or C motif revealed that hypertonicity induces all three types in MDCK cells. Reverse transcription and polymerase chain reaction showed that each type was expressed in a tissue-specific manner. Primer extension and/or RNase protection assays as well as transfection assays into MDCK cells demonstrated that exons 1A, 1B, and 1C+D have independent transcription initiation sites under control of independent promoters. Diverse mRNA isoforms are regulated by hypertonicity and are expressed in a tissue-specific manner.

Animals↗
PubMed1995

Myeloperoxidase-antineutrophil cytoplasmic antibody-positive crescentic glomerulonephritis complicating the course of Graves' disease: report of three adult cases.

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis has been recently recognized in Graves' disease patients treated with propylthiouracil. We have experienced three adult cases of Graves' disease with main features being renal derangements. All three patients, who were between the ages of 22 and 82 years, had been treated with propylthiouracil for 2 to 5 years after a diagnosis of Graves' disease. After several weeks of upper respiratory tract infection or flu-like symptoms, they abruptly began to manifest proteinuria and hematuria concomitant with severe anemia. Their serum creatinine increased from normal levels to 1.2 to 3.6 mg/dL. Renal biopsy revealed crescentic glomerulonephritis without deposition of immune complexes (ie, pauci-immune type). Crescent formations were observed in 40% to 60% of the glomeruli in all three cases. The serum from the patients revealed positive perinuclear-ANCA and negative cytoplasmic-ANCA (C-ANCA) pattern, and myeloperoxidase (MPO)-ANCA titers were 120 to 502 ELISA Units/mL (normal, < 10 ELISA Units/mL). A withdrawal of propylthiouracil with or without immunosuppressive therapy ameliorated their renal derangements. Graves' disease patients should be placed under vigilant observation by monitoring their urinalysis and serum creatinine, especially when being treated with antithyroid drugs and when suffering from flu-like symptoms.

Adult↗
PubMed1995

Stable and functional expression of the CIC-3 chloride channel in somatic cell lines.

The CIC family is the superfamily of voltage-gated Cl- channels. Although the CIC channels expressed in Xenopus oocytes have been characterized, their channel properties are still poorly understood. We recently cloned a unique member of the CIC family, CIC-3, that is expressed abundantly in neurons. Its channel activity was regulated by phorbol esters. Now, we have established a stably transfected somatic cell line expressing functional CIC-3 channels and examined the CIC-3 single-channel current by patch-clamp techniques. In inside-out patches from the stably transfected cells, a rise of bath Ca2+ concentration in the physiological range of intracellular Ca2+ concentrations inhibited the CIC-3 single-channel currents. This inhibition by Ca2+ was independent of phosphorylation and ATP. Thus, the CIC-3 channel is a Ca(2+)-sensitive Cl- channel localized in neuronal cells, and its Ca2+ sensitivity implies a physiological role in neuronal functions.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1995

Cloning, tissue distribution, and intrarenal localization of ClC chloride channels in human kidney.

Two kidney-specific chloride channels, ClC-K1 and ClC-K2, have been isolated from rat kidney. In the present study, we sought to isolate human homologue of rat ClC-K2 chloride channel that was present in the thick ascending limb of Henle's loop and collecting ducts. Human kidney cDNA library was screened with the whole rat ClC-K2 cDNA probe. Two highly homologous but not identical cDNAs were isolated and sequenced. Northern analysis showed that both clones were expressed only in kidney among various human tissues, demonstrating that kidney-specific ClC family members were also present in human kidney. Because both clones had almost the same nucleotide identity (approximately 80%) with rat ClC-K2, we could not determine by sequence alone which human clone corresponded to rat ClC-K2. Accordingly, we performed reverse transcription PCR using dissected human nephron segments and identified the site of expression of each clone in human nephron segments. One clone was only expressed in the thin limb of Henle's loop and the other was expressed in glomeruli, proximal tubules, and collecting ducts. We identified the latter clone as human ClC-K2 based on the localization of rat ClC-K1 and ClC-K2. Identification of human ClC-K2 clone will be of help in understanding the genetic involvement of chloride channel in disorders of chloride transport such as Bartter's syndrome.

Amino Acid Sequence↗
PubMed1995

Establishment of a T-cell line from lymphocytes presumably implicated in posttransfusion graft-versus-host disease.

Posttransfusion graft-versus-host disease (PTGVHD) is known to develop in immunocompetent patients exhibiting clinical symptoms such as erythroderma, fever, liver dysfunction, diarrhea and pancytopenia. It is speculated that transfused blood donors' lymphocytes might recognize the recipients' HLAs as alloantigens. The thus stimulated lymphocytes might proliferate, expand and finally attack the host's immune system or tissues. However, details regarding these expanded donor cells such as: (1) whether they represent one clone or more, (2) the composition of lymphocyte subsets, and (3) the target HLA antigens of recipients, are not clear, since T-cell lines derived from PTGVHD patients have not yet been obtained. The aim of this study is to characterize T-cells responsible for PTGVHD and to identify their target molecules. For that purpose, we attempted to establish T-cell lines derived from a PTGVHD patient. We show that the established T-cell line, proven to be derived from donor lymphocytes, showed a CD4+ phenotype and had cytotoxic activities. Furthermore, we describe that the target of the cytotoxic T-cell line (CTL) is an HLA-DRB1*0405-related molecule of the patient.

Base Sequence↗
PubMed1995

Effects of (-)-epigallocatechin-3-O-gallate (green tea tannin) on the life span of stroke-prone spontaneously hypertensive rats.

1. Effect of (-)-epigallocatechin-3-O-gallate (EGCG), a condensed tannin isolated from green tea leaves, on the life span and hypertensive lesions in the stroke-prone spontaneously hypertensive rat (SHRSP) was compared with that of persimmon tannin. 2. Long-term administration of either 0.5% EGCG or 0.5% persimmon tannin to SHRSP inhibited the incidence of stroke and prolonged the life span, but did not affect the blood pressure. 3. These results indicate that EGCG may prevent incidence of stroke due to the radical scavenging action and inhibition of lipid peroxidation, and may result in prolonging the life span of SHRSP, as in the case of persimmon tannin.

Animals↗
PubMed1995

The receptor occupation and plasma concentration of NKY-722, a water-soluble dihydropyridine-type calcium antagonist, in spontaneously hypertensive rats.

1. The occupation in vivo by NKY-722 of 1,4-dihydropyridine (DHP) calcium antagonist receptors in myocardium, aorta and cerebral cortex was investigated. At 1 and 3 h after oral administration of NKY-722 (3 mg kg-1) in spontaneously hypertensive rats (SHR), there was a significant (44 and 41%, respectively) decrease in the number of myocardial (+)-[3H]-PN 200-110 binding sites (Bmax) compared to control values. A greater reduction of Bmax values was observed at 1 (86%), 3 (88%), 6 (63%) and 12 (46%) h later by a higher dose (10 mg kg-1) of this drug. The occupation of myocardial 1,4-DHP calcium antagonist receptors after oral administration of NKY-722 correlated significantly with its plasma concentration. There was a significant decrease in cerebral cortical (+)-[3H]-PN 200-110 binding (Bmax) at 1 and 3 h after oral administration of NKY-722 (10 mg kg-1). 2. Oral administration of nicardipine (10 mg kg-1) in SHR caused a significant reduction of Bmax values for (+)-[3H]-PN 200-110 binding in myocardium at 1 and 3 h later and in cerebral cortex at 1 h later. 3. The in vivo specific binding of (+)-[3H]-PN 200-110 in particulate fractions of aorta of SHR was significantly (79 and 83%, respectively) reduced at 1 and 6 h after oral administration of NKY-722 (3 mg kg-1), while myocardial (+)-[3H]-PN 200-110 binding was decreased by 52% only at 1 h later. Also, nicardipine administration reduced in vivo ( + )-[3H]-PN 200-110 binding in aorta at 1 and 6 h later and in myocardium at 1 h later. On the other hand, the administration of both NKY-722 and nicardipine had no significant effect on in vivo (+ )-[3H]-PN 200-110 binding in cerebreal cortex.4 It is concluded that NKY-722 may exert more selective and sustained occupation in vivo of 1,4-DHP calcium antagonist receptors in vascular tissues of SHR than in myocardial and brain tissues.

Administration, Oral↗
PubMed1995

Desensitization of endothelin-1 binding by vasopressin via a cAMP-mediated pathway in rat CCD.

In renal collecting ducts, endothelin-1 (ET-1) inhibits Na+ reabsorption and antagonizes the effects of arginine vasopressin (AVP). Whether AVP may affect ET-1 action in the collecting ducts that mainly express the ETB receptor subtype, however, remains unknown. Since ETB, but not ETA, possesses a consensus amino acid sequence for possible phosphorylation by protein kinase A (PKA), we hypothesized that AVP may influence ET-1 binding to the ETB receptor via PKA. In microdissected rat cortical collecting ducts, the specific ET-1 binding decreased by 35% (15.6 +/- 4.4 vs. 24.0 +/- 3.6 amol/mm in control) following 20-min preincubation with 10(-7) M AVP. This decrease in ET-1 binding was mimicked by 10(-5) M forskolin and by 10(-4) M dibutyryl (DB) adenosine 3',5'-cyclic monophosphate (cAMP), indicating that this heterologous desensitization may be caused by a cAMP-dependent mechanism. Moreover, N-(2([3-(4-bromophenyl)-2-propenyl]-amino]-ethyl)-5- isoquinolinesulfonamide (H-89) and the Rp diastereoisomer of cAMP, Rp-cAMPS, which are both PKA-specific inhibitors, eliminated AVP-induced ETB receptor desensitization. The reduction in ET-1 binding was characterized by a decrease in binding affinity [dissociation constant (Kd) = 4 vs. 2 nM in control] with no change in maximal binding capacity. In contrast, forskolin and DBcAMP had no effect on ET-1 binding in endothelium-denuded aortic strips, which mainly express ETA subtype. These results showed that AVP rapidly downregulates the ETB receptor by reducing Kd through a PKA-dependent pathway. Thus ET-1 and AVP may act in a mutually antagonizing manner in the renal collecting ducts.

Amino Acid Sequence↗
PubMed1995

Localization and functional characterization of rat kidney-specific chloride channel, ClC-K1.

To investigate the physiological role of a kidney-specific chloride channel (ClC-K1), we sought to determine its exact localization by immunohistochemistry and its functional regulation using Xenopus oocyte expression system. The antiserum specifically recognized a 70-kD protein in SDS-PAGE of membrane protein from rat inner medulla and an in vitro translated ClC-K1 protein. Immunohistochemistry revealed that ClC-K1 was exclusively localized to the thin limb of Henle's loop in rat inner medulla. In comparison with the immunostaining with anti-aquaporin-CHIP antibody that only stains the descending thin limb of Henle's loop (tDL), ClC-K1 was found to be localized only in the ascending limb (tAL) which has the highest chloride permeability among nephron segments. Immunoelectron microscopy confirmed that the staining of ClC-K1 in tAL was observed in the region of both apical and basolateral plasma membranes. Expressed chloride current in Xenopus oocytes by ClC-K1 cRNA was regulated by extracellular pH and extracellular calcium. Furosemide inhibited the expressed current (Ki = 100 microM), whereas N-ethyl-maleimide stimulated the current. These functional characteristics were consistent with the in vitro perfusion studies of chloride transport in tAL. The localization and the functional characteristics described here indicate that ClC-K1 is responsible for the transepithelial chloride transport in tAL.

Animals↗
PubMed1995

Anti-inflammatory effect of flurbiprofen tape applied percutaneously to rats with adjuvant-induced arthritis.

The anti-inflammatory effect of flurbiprofen tape (FP-T) by topical application was investigated, and the findings were compared with the results of oral administration of flurbiprofen to adjuvant arthritic rats. The topical application of FP-T significantly suppressed both applied and non-applied hind paw edema, with a potency similar to that seen with the oral administration of flurbiprofen. Body weight also increased with these treatments. Plasma levels of flurbiprofen differed little between topical application of FP-T and oral administration of flurbiprofen. Gastric damage induced by topical application of FP-T was significantly less than that seen in case of oral administration of flurbiprofen. These results suggest that the anti-inflammatory effects of FP-T cannot be entirely explained by flurbiprofen permeating inflamed tissue below the application site; rather, flurbiprofen penetrating into the systemic circulation may explain these actions.

Administration, Topical↗
PubMed1995

Relationship between molecular weights of pectin and hypocholesterolemic effects in rats.

Hypocholesterolemic activities and other properties of three different molecular weight pectin were examined. The low-molecular-weight pectin (M(r) not equal to 66,000) obtained by decomposition of original pectin (M(r) not equal to 750,000) had the properties of low viscosity and high solubility, but it lost hypocholesterolemic activities in rats. On the other hand, the medium-molecular-weight pectin (M(r) not equal to 185,000) had characteristics of both low viscosity and hypocholesterolemic activities.

Animals↗
PubMed1995

Production of mice entirely derived from embryonic stem (ES) cell with many passages by coculture of ES cells with cytochalasin B induced tetraploid embryos.

Mice entirely derived from ES cells were obtained from aggregates of TT2 ES cells and cytochalasin B induced tetraploid embryos. Tetraploid embryos were cocultured with ES cells in a well on the Multiplate-Terasaki. After embryo transfer of the aggregates, the male newborns were recovered normally after Cesarean section and reached adulthood. The male mice exhibited complete pigmentation of the eye and coat, suggesting ES cell contributions alone. Alkaline phosphatase-1 analysis yielded no evidence of tetraploid cells in the kidney or liver. The TT2-derived males were fertile, produced normal offspring, and exclusively transmitted the TT2 genotype to their progeny. This result clearly shows that ES cells are able to support complete fetal development.

Animals↗
PubMed1995

The effects of aging on the rat bladder and its innervation.

1) Measurements of the cystometrogram, of the responsiveness of bladder muscle to pelvic nerve efferent stimulation and of the sensitivity of the pelvic nerve afferents to pressure and volume during distensions have been made in the bladders of young adult (2-3 months) and aged (26-29 months) rats, anesthetized with mixtures of urethane and chloralose. 2) The pressure-volume relationship differed in young adult and aged rats. The bladders of the aged rats held up to nearly six times the volume of the young animals, and these volumes were accommodated at lower pressures in the aged animals. The pressure at which micturition contractions appeared was similar in young adult and aged animals. 3) The passive pressure associated with each of a series of distending volumes was recorded when a pelvic nerve was cut unilaterally. The distal cut end of this cut pelvic nerve was stimulated for 10 s at 20 Hz, using square wave pulses of 10 V and 1.0 ms. The active pressure-volume relationship was constructed from this data. Both the active and the passive relationships were shifted to the right in the aged animals, and it was evident that aging was associated with a reduction in the maximal pressure generated during pelvic nerve stimulation. Also the change in intravesical pressure induced by bladder contraction was less in aged animals. 4) The most sensitive mechanoreceptor afferents appear to have pressure and volume thresholds that do not change significantly during aging. While the distension-sensitive afferents in the pelvic nerve appear to have a similar sensitivity to intravesical pressure in young adult and aged rats, they were less able to monitor volume in the aged animals. The stimulus response relationship for volume was often less steep in the aged animals. 5) In this study, aging was shown to be associated with a large increase in bladder volume and a reduced sensitivity of pelvic nerve afferents to volume, and a reduced ability to raise bladder pressure during contraction of bladder smooth muscle. The changes in bladder function associated with aging are discussed.

Aging↗
PubMed1995

[A drug-induced transient Fanconi syndrome associated with pure red cell aplasia: pathophysiology of the electrolyte disorders].

A 55-year-old female with a long history of pure red cell aplasia temporarily manifested Fanconi syndrome with hypophosphatemia, hypouricemia, glycosuria, acidic amino aciduria, but not metabolic acidosis nor hypokalemia. These abnormalities completely resolved in 3-4 weeks after withdrawal of several drugs, suggesting that the cause of her Fanconi syndrome could be attributed to a drug or a combination of multiple drugs, though lymphocyte stimulating tests revealed negative results for all possible drugs. Postmortem specimen of her kidneys showed mild mesangial proliferation without significant changes in tubular and interstitial regions. Massive ferrous precipitations were found in the zona glomerulosa of the adrenal glands. The pathophysiology of Fanconi syndrome shown in the patient was likely to have been a drug-induced transient and mild dysfunction of the Na+/K+ pump of the renal proximal tubules, which might also explain the selective amino aciduria. The absence of hypokalemia corroborates well with both a lack of bicarbonaturia and hemochromatosis-induced adrenal insufficiency. Patients with a renal dysfunction associated with electrolyte derangements and without proteinuria or azotemia should be under vigilant observation when using many drugs.

Fanconi Syndrome↗
PubMed1994

Sigma (12-16 Hz) and beta (20-28 Hz) EEG discriminate NREM and REM sleep.

All night sleep EEG from ten normal students were subjected to FFT spectral analyses. Delta (0.3-3 Hz), sigma (12-16 Hz) and beta (20-28 Hz) EEG showed strongly oscillating patterns across the night. The scattergram of sigma versus beta revealed two separate clusters. One cluster demonstrated a positive linear correlation between sigma and beta. The second cluster showed a range of beta, but a stable, low level of sigma activity. Points in the former cluster consisted of those from NREM epochs, and in the latter, from REM epochs. The present results suggest that REM and NREM EEG are composed of two sets of EEG frequency components, perhaps reflecting different neuronal pools.

Adult↗