Histopathologic findings of renal allografts surviving more than 10 years after transplantation.
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Adolescent↗
Biomedical subjects
Y Yamaguchi
Publications and source records attributed to Y Yamaguchi.
Altered endothelium-dependent responsiveness in the aortas and renal arteries of Otsuka Long-Evans Tokushima Fatty (OLETF) rats, a model of non-insulin-dependent diabetes mellitus.
We examined endothelium-dependent relaxation in the aortas and renal arteries of Otsuka Long-Evans Tokushima Fatty (OLETF) rats, a model of non-insulin-dependent diabetes mellitus, in comparison with non-diabetic Long-Evans Tokushima Otsuka rats as controls. Acetylcholine-induced relaxation in both arteries was attenuated, and the attenuation was restored to the control level by indomethacin. The relaxation was inhibited completely in the aortas, but only partially in renal arteries by N(G)-nitro-L-arginine methyl ester, and the degree of the latter inhibition was greater in OLETF rats than in the controls. The relaxation was inhibited by aminoguanidine in both arteries of OLETF rats but not in the controls. Serum NO(2) plus NO(3) levels significantly increased in OLETF rats. These results suggest that impairment of relaxation in OLETF rat arteries is due to increased release of contractile factors but not decreased release of nitric oxide.
Acetylcholine↗
Differentiation/regeneration of oligodendrocytes entails the assembly of a cell-associated matrix.
Oligodendrocytes assemble and maintain CNS myelin. We have shown that adhesion of ovine oligodendrocytes to the substratum, GRASP - a novel, horse serum heparin-binding glycoprotein - initiates their myelinogenic phenotype. Synthesis and vectorial transport to the plasma membrane of heparan sulfate proteoglycans is one of the many events that ensue upon adhesion. Proteoglycans play key roles in defining the line of communication between cells and their microenvironment. The nature of their association with cells varies. Often, proteoglycans are part of a complex extracellular network that either surrounds cells or is restricted to smaller areas of their surface. Such extracellular matrices form an integral part of the machinery that regulates cell function. As part of an effort to delineate the events and identify the molecules involved in the adhesion-induced-regeneration and possibly in differentiation of OLGs, we have undertaken to define the full repertoire of OLG proteoglycans. Oligodendrocytes express surface-associated proteoglycans and also secrete them to the medium. However, we observed a clear distinction between secreted and surface-associated proteoglycans in terms of types, temporal regulation and spacial distribution. Oligodendrocytes secrete chondroitin sulfate proteoglycans and keratan sulfate proteoglycans but have only heparan sulfate proteoglycans associated with their surface. Secreted proteoglycans are temporally modulated but adhesion-independent, whereas surface-associated proteoglycans are adhesion-induced. Herein, we present the biochemical characterization of oligodendrocyte proteoglycans. We report that a significant fraction of the surface-associated heparan sulfate proteoglycans are assembled into a cell-associated matrix. This finding is important. First, it reveals a closer parallel than hitherto documented with events that signal Schwann cell myelination. Second, it implicates HSPGs in the establishment of OLG differentiated phenotype. Third, it brings OLGs in tune with other cell types where the ECM (broadly defined) is critical for the orchestration of cues that generate tissue-specific gene expression and phenotypes.
Animals↗
FACT relieves DSIF/NELF-mediated inhibition of transcriptional elongation and reveals functional differences between P-TEFb and TFIIH.
We report that the chromatin-specific transcription elongation factor FACT functions in conjunction with the RNA polymerase II CTD kinase P-TEFb to alleviate transcription inhibition by DSIF (DRB sensitivity-inducing factor) and NELF (negative elongation factor). We find that the kinase activity of TFIIH is dispensable for this activity, demonstrating that TFIIH-mediated CTD phosphorylation is not involved in the regulation of FACT and DSIF/NELF activities. Thus, we propose a novel transcriptional regulatory network in which DSIF/NELF inhibition of transcription is prevented by P-TEFb in cooperation with FACT. This study uncovers a novel role for FACT in the regulation of transcription on naked DNA that is independent of its activities on chromatin templates. In addition, this study reveals functional differences between P-TEFb and TFIIH in the regulation of transcription.
DNA-Binding Proteins↗
Calcium-channel blocker attenuates Kupffer cell production of cytokine-induced neutrophil chemoattractant following ischemia-reperfusion in rat liver.
We investigated the effects of the calcium-channel blocker verapamil hydrochloride on the production of cytokine-induced neutrophil chemoattractant (CINC) following reperfusion injury in rat liver. Ischemia was induced for 30 min by portal vein occlusion. Animals were pretreated with intravenous injection of verapamil hydrochloride (2.5 mg/kg) 5 min before vascular clamp. Verapamil hydrochloride limited increases in the chemoattractant compared with nonpretreated rats. Most cells immunostained for chemoattractant were ED2-positive macrophages in sinusoids. In vitro chemoattractant production by Kupffer cells isolated from animals pretreated with verapamil hydrochloride was significantly lower than by Kupffer cells from nonpretreated animals. Expression of transcripts in liver for chemoattractant peaked 3 hr after reperfusion in nonpretreated animals, while pretreatment with verapamil hydrochloride significantly decreased chemoattractant mRNA levels. In vitro chemoattractant production could be induced in naive Kupffer cells after stimulation with oxygen radicals generated by hypoxanthine and xanthine oxidase, but verapamil hydrochloride prevented these increases. We concluded that the calcium-channel blocker verapamil hydrochloride significantly attenuates chemoattractant release by Kupffer cells after ischemia-reperfusion in the rat liver.
Animals↗
Identification of a 5' splice junction mutation in the debranching enzyme gene in a Japanese patient with glycogen storage disease type IIIa.
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Adult↗
Reduced interleukin-12, interleukin-18, and interferon-gamma production with prolonged rat hepatic allograft survival after donor-specific blood transfusion.
Interferon-gamma is a key immunoregulatory cytokine involved in acute graft rejection. Immunologic unresponsiveness to organ allografts has been induced by pretransplantation donor-specific blood transfusion, both experimentally and clinically. We investigated interferon-gamma production and intragraft gene expression of type-1 T-helper cytokines such as interleukin-12 and -18 and type-2 T-helper cytokines such as interleukin-10 and transforming growth factor-beta in rats receiving hepatic allografts after such transfusions. The animals were divided into four groups: group I received isografts; group II received allografts; group III received allografts after donor-specific transfusion; and group IV received allografts and was treated with FK 506. Donor blood given seven days prior to transplantation significantly prolonged allograft survival. The serum interferon-gamma concentrations in group II increased, peaking on day 5 and then decreasing. Serum interferon-gamma concentrations in groups I, III, and IV were significantly lower than those observed in group II, as were levels of interleukin-12 and interleukin-18 mRNA in the graft. Transforming growth factor-beta and interleukin-10 mRNA levels in grafts in transfused animals were significantly greater than those in the untreated allograft group. Interleukin-12 and -18 mRNA transcripts in an allogeneic mixed lymphocyte reaction were inhibited by interleukin-10 and transforming growth factor-beta. These results suggest that interleukin-12 and -18 expression in hepatic allografts is inhibited in the immunologically unresponsive state induced by donor-specific transfusion.
Animals↗
1H and 13C NMR assignments for the glycans in glycoproteins by using 2H/13C-labeled glucose as a metabolic precursor.
In order to understand the role of the glycans in glycoproteins in solution, structural information obtained by NMR spectroscopy is obviously required. However, the assignment of the NMR signals from the glycans in larger glycoproteins is still difficult, mainly due to the lack of appropriate methods for the assignment of the resonances originating from the glycans. By using [U-13C6, 2H7]glucose as a metabolic precursor, we have successfully prepared a glycoprotein whose glycan is uniformly labeled with 13C and partially with D at the sugar residues. The D to H exchange ratios at the C1-C6 positions of the sugar residues have been proven to provide useful information for the spectral assignments of the glycan in the glycoprotein. This is the first report on the residue-specific assignment of the anomeric resonances originating from a glycan attached to a glycoprotein by using the metabolic incorporation of hydrogen from the medium into a glycan labeled with [U-13C6, 2H7]glucose.
Animals↗
A peculiar vacuolization in the kidney transplant of a child treated with tacrolimus.
Tacrolimus (TAC) is a useful immunosuppressive agent in the prevention of rejection. However, the blood level between its therapeutic and toxic levels is narrow such that its nephrotoxicity is a problem. Moreover, its bioavailability and pharmacokinetics are highly variable. We experienced a case of acute nephrotoxicity, in which the blood level rose about 10 times above the expected level. We found a peculiar vacuolization in the transplant biopsy specimen. This change showed a marked vacuolization of the tubular cells, suggestive of acute nephrotoxicity by TAC.
Adolescent↗
Super long-term surviving two renal grafts with severe arteriolosclerosis and glomerulosclerosis.
Two long-term renal transplant survivors, for about 20 yr, with unusual histological features in the allograft kidney are reported. In both cases, marked hyalinosis was observed in the arterioles of the transplanted kidney, despite never having been administered cyclosporine or tacrolimus. The cause remains unknown at the present time, but we think that the changes could be multifactorial in origin, including due to aging of the graft, hypertension, hyperlipidemia and chronic rejection. We conclude that histological analysis of the allograft kidney must be performed in long-term renal transplant survivors, in order to understand the histological changes in the chronic phase after kidney transplantation and to predict the prognosis of the graft.
Adult↗
Reference value of six-minute walking distance in healthy middle-aged and older subjects.
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Aged↗
Lack of co-ordinate expression of the alpha1(I) and alpha1(III) procollagen genes in fibroblast clonal cultures.
BACKGROUND: Several extracellular matrix genes, most notably alpha1(I) and alpha1(III) procollagen, are reported to be co-ordinately expressed in cultures of dermal fibroblasts. However, it remains unclear whether the expression of these genes is truly co-ordinate or whether it may be the result of averaging the phenotypic expression of different fibroblast subpopulations present within each culture. Objectives To determine by Northern analysis the correlation between alpha1(I) and alpha1(III) procollagen mRNA levels in clonal populations of human dermal fibroblasts. METHODS: As previously described, clonal cultures were derived from parent strains of human dermal fibroblasts by a microscopically controlled dilution technique and by stimulation of single cells with low oxygen tension in the early phases of clonal growth. RESULTS: In agreement with previous reports, we found that baseline steady-state levels of alpha1(I) procollagen mRNA were co-ordinately regulated with the alpha1(III) procollagen mRNA in 26 parent strains (r = 0. 9003; P < 0.0001). However, this close correlation between the expression of these two procollagen chains was absent in a total of 40 unselected clonal strains derived from four of the parent cultures (r = 0.5745; P < 0.0001). Moreover, this intrachain heterogeneity in alpha1(I) and alpha1(III) procollagen mRNA levels in clonal cultures was statistically significant from that measured in parent strains (P = 0.0016). CONCLUSIONS: alpha1(I) and alpha1(III) procollagen mRNA levels in clonal cultures do not show the tight co-ordinate regulation observed in non-clonal cultures, suggesting that these two genes operate under different sets of regulatory controls. This clonal heterogeneity may provide additional flexibility to the process of tissue repair and fibroblast clonal expansion.
Adult↗
Hepatitis C virus quasispecies and response to interferon therapy in patients with chronic hepatitis C: a prospective study.
We prospectively examined whether the complexity of hepatitis C virus (HCV) quasispecies is related to the response to interferon (IFN) therapy. Among 64 patients who had histologically proven chronic hepatitis and were treated with natural IFN-alpha, 53 patients were analysed. The other 11 patients discontinued therapy because of adverse effects of IFN. The complexity of the hypervariable region 1 (HVR 1) in quasispecies was determined using both clone number determined by fluorescence single-strand conformation polymorphism (SSCP) and nucleotide diversity determined by direct sequencing. These parameters were measured not only before treatment but also at completion and 6 months after therapy, if serum HCV RNA was detectable. This population of patients was different from the general Japanese population with regard to the high prevalence of patients infected with genotype 2a or 2b (49%), who had a higher viral load than those with genotype 1b (P = 0.021). Twenty-two patients (41.5%) were sustained responders. Genotype non-1b (P = 0.0009) and a smaller clone number (P = 0.008) were significantly associated with a sustained response. In multivariate analysis, these variables were independently associated with a sustained response (i.e. genotype: odds ratio 6.84, 95% CI 1.84-30. 12; and clone number: odds ratio 1.26, 95% CI 0.99-1.68). The clone number and nucleotide diversity did not change significantly between pretreatment and at completion or 6 months after therapy. These results suggest that lower complexity of HVR 1 quasispecies predicts a preferable response to IFN therapy that is independent of viral load, especially in the population of the relatively high prevalence of patients infected with genotype 2.
Adolescent↗
Plant mercaptopyruvate sulfurtransferases: molecular cloning, subcellular localization and enzymatic activities.
Mercaptopyruvate sulfurtransferase (MST, EC 2.8.1.2) and thiosulfate sulfurtransferase (TST, rhodanese, EC 2.8.1.1) are evolutionarily related enzymes that catalyze the transfer of sulfur ions from mercaptopyruvate and thiosulfate, respectively, to cyanide ions. We have isolated and characterized two cDNAs, AtMST1 and AtMST2, that are Arabidopsis homologs of TST and MST from other organisms. Deduced amino-acid sequences showed similarity to each other, although MST1 has a N-terminal extension of 57 amino acids containing a targeting sequence. MST1 and MST2 are located in mitochondria and cytoplasm, respectively, as shown by immunoblot analysis of subcellular fractions and by green fluorescent protein (GFP) analysis. However, some regions of MST1 fused to GFP were found to target not only mitochondria, but also chloroplasts, suggesting that the regions on the targeting sequence recognized by protein import systems of mitochondria and chloroplasts are not identical. Recombinant proteins, expressed in Escherichia coli, exhibited MST/TST activity ratios determined from kcat/Km values of 11 and 26 for MST1 and MST2, respectively. This indicates that the proteins encoded by both AtMST1 and AtMST2 are MST rather than TST type. One of the hypotheses proposed so far for the physiological function of MST and TST concerns iron-sulfur cluster assembly. In order to address this possibility, a T-DNA insertion Arabidopsis mutant, in which the AtMST1 was disrupted, was isolated by PCR screening of T-DNA mutant libraries. However, the mutation had no effect on levels of iron-sulfur enzyme activities, suggesting that MST1 is not directly involved in iron-sulfur cluster assembly.
Amino Acid Sequence↗
Point mutation in intron 11 of Bruton's tyrosine kinase in atypical X-linked agammaglobulinemia.
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Agammaglobulinaemia Tyrosine Kinase↗
Galpha(12) and galpha(13) inhibit Ca(2+)-dependent exocytosis through Rho/Rho-associated kinase-dependent pathway.
The release of neurotransmitters is known to be regulated by activation of heterotrimeric G protein-coupled receptors, although precise mechanisms have not yet been elucidated. To assess the role of the G(12) family of heterotrimeric G proteins in the regulation of neurotransmitter release, we established PC12 cell lines that expressed constitutively active Galpha(12) or Galpha(13) using an isopropyl-beta-D-thiogalactoside-inducible expression system. In the cells, expression of constitutively active Galpha(12) or Galpha(13) inhibited the high K(+)-evoked [(3)H]dopamine release without any effect on the high K(+)-induced increase in intracellular Ca(2+) concentration. A Ca(2+) ionophore ionomycin-induced [(3)H]dopamine release was also inhibited by the expression of active Galpha(12) or Galpha(13). These inhibitory effects of Galpha(12) and Galpha(13) on [(3)H]dopamine release were mimicked by the expression of constitutively active RhoA. In addition, Y-27632, and inhibitor of Rho-associated kinase, a downstream Rho effector, completely abolished the inhibition of [(3)H]dopamine release by Galpha(12), Galpha(13), and RhoA. These results indicate that Ca(2+)-dependent exocytosis is regulated by Galpha(12) and Galpha(13) through a Rho/Rho-associated kinase-dependent pathway.
Animals↗
Involvement of keratinocyte activation phase in cutaneous graft healing: comparison of full-thickness and split-thickness skin grafts.
BACKGROUND: Little is known about keratinocytic activation in the graft take and healing process. OBJECTIVE: To investigate the clinical and molecular differences between pure epidermal sheet graft (PESG), split-thickness skin graft (STSG), and full-thickness skin graft (FTSG). METHODS: Three different thickness skin grafts (PESG, STSG, and FTSG) were performed onto three kinds of porcine wounds: shallow, deep, and full. Graft take, contraction, and Ki-67 and beta1 integrin expression in epidermis were studied. RESULTS: All grafts took well. As expected, full wounds covered by PESG and STSG contracted more than those covered by FTSG, whereas shallow wounds covered by FTSG contracted more than those covered by STSG. No difference in contracture was observed among deep wounds covered by PESG, STSG, and FTSG. Up-regulation of Ki-67 and beta1 integrin expression was greater in PESG and STSG, compared with little expression in FTSG. CONCLUSION: The keratinocytic activation phase may occur both in the STSG and PESG healing process, as well as serum imbibition, inosculatory, and revascularization phases.
Animals↗
Role of nitric oxide and superoxide in acute cardiac allograft rejection in rats.
The role of NO and superoxide (O(2)(-)) in tissue injury during cardiac allograft rejection was investigated by using a rat ex vivo organ perfusion system. Excessive NO production and inducible NO synthase (iNOS) expression were observed in cardiac allografts at 5 days after cardiac transplantation, but not in cardiac isografts, as identified by electron spin resonance spectroscopy and Northern blotting. Cardiac isografts or allografts obtained on Day 5 after transplantation were perfused with Krebs bicarbonate buffer with or without various antidotes for NO or O(2)-, including N(omega)-monomethyl-L-arginine (L-NMMA; 1 mM), 2-phenyl-4,4,5, 5-tetramethylimidazoline-1-oxyl 3-oxide (PTIO; 100 microM), 4-amino-6-hydroxypyrazolo[3,4-d]pyrimidine (AHPP; a xanthine oxidase inhibitor; 100 microM), and superoxide dismutase (SOD; 100 units/ml). Treatment of the cardiac allografts with PTIO showed most remarkable improvement of the cardiac injury as revealed by significant reduction in aspartate transaminase, lactate dehydrogenase, and creatine phosphokinase concentrations in the perfusate. Similar but less potent protective effect on the allograft injury was observed by treatment with L-NMMA, AHPP, and SOD. Immunohistochemical analyses for iNOS and nitrotyrosine indicated that iNOS is mainly expressed by macrophages infiltrating the allograft tissues, and nitrotyrosine formation was demonstrated not only in macrophages but also in cardiac myocytes of the allografts, providing indirect evidence for the generation of peroxynitrite during allograft rejection. Our results suggest that tissue injury in rat cardiac allografts during acute rejection is mediated by both NO and O(2)(-), possibly through peroxynitrite formation.
Acute Disease↗