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H Azuma

Publications and source records attributed to H Azuma.

At least 55 records · Page 3Linked to original sources
PubMed1999

In vitro and in vivo evaluation of the enhancing activity of glycyrrhizin on the intestinal absorption of drugs.

PURPOSE: The enhancing activity of dipotassium glycyrrhizinate (Grz) on the intestinal absorption of drugs has been demonstrated in an in vitro study using Caco-2 cell monolayers and in an in vivo absorption study in rats. METHODS: The hydrolysis of Grz by luminal content and mucosa of the rat colon was investigated. The absorption-enhancing activity of Grz and its hydrolysates was estimated by changes in transepithelial electrical resistance (TEER) and the permeation of sodium fluorescein (Flu-Na) in Caco-2 cell monolayers. It was further evaluated through the absorption of salmon calcitonin (sCT) in the rat colon. RESULTS: Grz was not hydrolyzed to glycyrrhetinylmonoglucuronide (GrMG) and glycyrrhetinic acid (GA) by colonic mucosa, but, rather by the beta-glucuronidase in colonic flora. The hydrolysis of Grz to GrMG was extremely slow and the GrMG produced was rapidly regenerated to GA. Grz and GrMG had no effect on TEER nor on the permeability of Flu-Na across Caco-2 cell monolayers. On the other hand, GA decreased TEER and increased the permeability of Flu-Na in a dose-dependent manner. However, Grz and GrMG enhanced the plasma calcium-lowering effect of sCT after administration in the rat colon. The coadministration of sCT and GA in the rat colon induced the strongest plasma calcium-lowering effect and the highest plasma concentration of sCT. CONCLUSIONS: The in vivo enhancing-activity of Grz in the absorption of drugs is dependent on GA, a hydrolysis product of Grz resulting from the action of beta-glucuronidase in intestinal flora.

Animals↗
PubMed1999

Accelerated intimal hyperplasia and increased endogenous inhibitors for NO synthesis in rabbits with alloxan-induced hyperglycaemia.

1. We examined whether endogenous inhibitors of NO synthesis are involved in the augmentation of intimal hyperplasia in rabbits with hyperglycaemia induced by alloxan. 2. Four weeks after the endothelial denudation of carotid artery which had been performed 12 weeks after alloxan, the intimal hyperplasia was greatly augmented with hyperglycaemia. The degree of hyperplasia was assessed using three different parameters of histopathological findings as well as changes in luminal area and intima: media ratio. 3. There were positive and significant correlations between intima:media ratio, plasma glucose, and concentrations of N(G)-monomethyl-L-arginine (L-NMMA) and N(G), N(G)-dimethyl-L-arginine (ADMA) in endothelial cells, that is, the intima:media ratio became greater as plasma glucose and endothelial L-NMMA and ADMA were increased. Furthermore, endothelial L-NMMA and ADMA were increased in proportion to the increase in plasma glucose. 4. In contrast, there were inverse and significant correlations between cyclic GMP production by carotid artery strips with endothelium and plasma glucose, between cyclic GMP production and endothelial L-NMMA and ADMA, and between the intima:media ratio and cyclic GMP production. 5. Exogenously applied L-NMMA and ADMA inhibited cyclic GMP production in a concentration-dependent manner. IC50 values were determined to be 12.1 microM for the former and 26.2 microM for the latter. The cyclic GMP production was abolished after the deliberate removal of endothelium from the artery strips. 6. These results suggest that the augmentation of intimal hyperplasia with hyperglycaemia is closely related to increased accumulation of L-NMMA and ADMA with hyperglycaemia, which would result in an accelerated reduction in NO production/release by endothelial cells.

Alloxan↗
PubMed1999

High prevalence of Epstein-Barr virus type A strain with the 30 b.p. deletion of the latent membrane protein-1 gene in a Japanese population.

BACKGROUND: The pathogenic activity of Epstein-Barr virus (EBV) with a characteristic 30 b.p. deletion of the latent membrane protein-1 (LMP-1) gene is controversial. We analyzed the LMP-1 gene and two major strains of EBV, type A and type B, in Japanese patients with EBV-associated disease. METHODS: We directly sequenced the carboxy terminal part of the LMP-1 gene from 15 EBV-infected patients; 10 patients with infectious mononucleosis (IM) and one patient each with Hodgkin's disease, B cell lymphoma, Wiskott-Aldrich syndrome (WAS), AIDS and atypical EBV infection (atEBV). The EBV subtype was studied by determining the 3' divergence of Epstein-Barr virus nuclear antigen (EBNA)-2 using polymerase chain reaction primers. RESULTS: Twelve of 15 patients had EBV with the 30 b.p. deletion and numerous point mutations of the LMP-1 gene, regardless of the disease. Two patients, one with IM and one with WAS, had EBV without the 30 b.p. deletion. One patient with atEBV had two types of LMP-1 gene, one with and one without the 30 b.p. deletion. Thirteen patients had EBV type A, the WAS patient had the type B strain and the atEBV patient had both types A and B. In the patient with atEBV, the two types of LMP-1 gene and two EBV subtypes were detected simultaneously. CONCLUSIONS: The characteristic 30 b.p. deletion of the LMP-1 gene is not an important factor in the pathogenesis of EBV-associated diseases. The EBV type A strain with the 30 b.p. deletion of the LMP-1 gene is prevalent in the Japanese population.

Epstein-Barr Virus Infections↗
PubMed1999

Gestational changes in endothelin-1-induced receptors and myometrial contractions in rat.

The present experiments were performed to characterize the gestational changes in endothelin (ET)-1-induced myometrial contractions and ET receptors in rat. ET-1-induced contractions were composed of two types: increases in resting tone and rhythmic contractions. The increase in resting tone was decreased at 7 days of gestation, but increased at 20 days. The increase in amplitude and frequency of rhythmic contractions remained unchanged during days 7-14 of gestation. Continuous rhythmic contractions were not produced by ET-1 near the term. Both contractions were inhibited by the antagonists BQ 123 and Ro 46-2005 but not by RES 701-1 or BQ 788. In binding studies, total binding sites of [1251]-ET-1 were unchanged, however higher affinity binding sites appeared during pregnancy in addition to the lower affinity sites. The specific [125I]-ET-1 binding in non-pregnant and pregnant myometrium was completely inhibited by unlabelled ET-1 and Ro 46-2005. In contrast, the proportion which was inhibited by BQ 123 was decreased during pregnancy. In conclusion, characteristic gestational changes were the augmentation of ET-1-induced increased resting tone near term, and the appearance of high affinity ET-1 binding sites and an increase in BQ 123-resistant ET-1 binding sites during pregnancy. Further investigations are needed to understand the physiological role of these changes.

Animals↗
PubMed1999

Simultaneous use of sodium deoxycholate and dipotassium glycyrrhizinate enhances the cellular transport of poorly absorbed compounds across Caco-2 cell monolayers.

The absorption-enhancing effect of a combination of sodium deoxycholate and dipotassium glycyrrhizinate in Caco-2 cell monolayers has been compared with that of the enhancers when used alone, and the mechanism of the enhancement was partially elucidated. The effect of the combined compounds was evaluated by measurement of transepithelial electrical resistance (TEER) and the cellular permeability of the water-soluble model compounds sodium fluorescein (MW 376.3) and fluorescein isothiocyanate dextran (MW 4400). The TEER of the monolayers decreased with increasing concentrations of dipotassium glycyrrhizinate in combination with 0.02% (w/v) sodium deoxycholate for 20 min, and reached a minimum at 1% (w/v) dipotassium glycyrrhizinate. Although a combination of 0.02% (w/v) sodium deoxycholate and 1% (w/v) dipotassium glycyrrhizinate enhanced the cellular permeability of sodium fluorescein and fluorescein isothiocyanate dextran, 0.02% (w/v) sodium deoxycholate and 1% (w/v) dipotassium glycyrrhizinate alone had no effect on either the TEER of the monolayers or the cellular transport of the water-soluble compounds. Sequential and separate exposure of the monolayers to each enhancer for 10 min had no effect on the TEER, but a marked decrease in TEER was observed when both compounds were used in combination. The enhancing effect of the combination of sodium deoxycholate and dipotassium glycyrrhizinate was inhibited by H7, a protein kinase C (PKC) inhibitor, suggesting that dipotassium glycyrrhizinate might enhance the activation of PKC via sodium deoxycholate. The combined use of these two enhancers had no toxic effects. These results provide useful, basic information on the action of these absorption enhancers on drugs for which absorption is limited owing to polarity or molecular size, or both.

Absorption↗
PubMed1999

[Role of L-arginine--endogenous NOS inhibitors--endothelin-1 pathway for the vascular remodelling].

Mechanisms of vascular remodelling process are complex and poorly understood. We describe herein the role of L-arginine-endogenous NOS inhibitors-endothelin-1 pathway for the vascular remodelling after endothelial denudation of the rabbit carotid artery. It is reportedly known that NO is a vasodilating substance, an inhibitor of platelet aggregation and adhesion, and an inhibitor of vascular smooth muscle cell proliferation and that endothelin-1, of which production is inhibited by NO, is a potent vasoconstrictor and a potent mitogen. An accumulation of endogenous inhibitors (L-NMMA and ADMA) in regenerated endothelial cells after the endothelial denudation was accompanied by the decreased NO generation, the increased endothelin-1 content within the vessel wall and the occurrence of intimal hyperplasia. Endothelin-1 content within the vessel wall was significantly increased after the exogenous L-NMMA administration for 2 weeks, suggesting that accumulated L-NMMA results in the decreased NO generation and, in turn, increases endothelin-1 content. Endothelin-1 facilitated the [3H]-L-NMMA uptake by endothelial cell and brought about the potentiation of L-NMMA-mediated inhibition of NO generation. These results strongly suggest that the L-arginine--endogenous NOS inhibitors--endothelin-1 pathway plays an active role for vascular remodelling.

Animals↗
PubMed1999

ATZ1993, an orally active and novel nonpeptide antagonist for endothelin receptors and inhibition of intimal hyperplasia after balloon denudation of the rabbit carotid artery.

The present experiments were designed to investigate the effect of ATZ1993 [3-carboxy-4,5-dihydro-1-[1-(3-ethoxyphenyl)propyl]-7-(5-pyrimidinyl)met hoxy-[1H]-benz[g]indazole] on the intimal hyperplasia after balloon endothelial denudation of the rabbit carotid artery. ATZ1993 inhibited the specific [125I]endothelin (ET)-1 binding not only to ET-receptor subtype A (ET(A)) with a pKi value of 8.69+/-0.02, but also to ET-receptor subtype B (ET(B)) with a pKi value of 7.20+/-0.03. Counterscreening in the binding assay (30 different receptors) confirmed that ATZ1993 had a high selectivity for ET receptors. Increases in intima:media ratio and DNA content in the vessel wall were significantly (P < 0.005) inhibited by ATZ1993 in a daily dose of 30 mg x 200 ml(-1) x kg(-1) for 1 week before and 6 weeks after balloon denudation. Inhibition of the intimal hyperplasia with ATZ1993 was determined as approximately 77% for increases in intima:media ratio and DNA content. Plasma concentrations of ATZ1993 ranged between 121.6+/-26.6 and 131.7+/-20.9 nM throughout experimental periods. Mean arterial blood pressure, heart rate and body weight gain remained unaffected by administering ATZ1993. These results demonstrate that ATZ1993 is a novel nonpeptide and nonselective ET(A)/ET(B)-receptor antagonist, and the agent when administered orally inhibits effectively intimal hyperplasia after balloon denudation of the rabbit carotid artery.

Administration, Oral↗
PubMed1999

Immunomodulatory functions of low-molecular weight hyaluronate in an acute rat renal allograft rejection model.

Low molecular weight hyaluronate (LMW-HA) blocks interactions between T lymphocyte CD44 and hyaluronate (HA), a heteropolysaccharide that is expressed on the surface of endothelial cells and ubiquitously in the extracellular matrix. This study was undertaken to assess the ability of LMW-HA to modify the course of experimental acute renal allograft rejection. Lewis (LEW) rats were bilaterally nephrectomized and received an orthotopic, fully MHC-mismatched, Wistar-Furth (WF) kidney transplant. Animals received either no treatment, low doses of cyclosporin A (CsA) on days 0 to 5, LMW-HA on days 0 to 5, or CsA plus LMW-HA on days 0 to 5 after transplantation. With no treatment, CsA monotherapy, or HA monotherapy, animals rejected their allografts at a median of 15, 13, and 7.5 d, respectively (P = NS). In contrast, combined CsA plus LMW-HA therapy prevented acute rejection and significantly prolonged graft survival (P = 0.008) to a median of 49.0 d. CsA/LMW-HA-treated grafts also demonstrated better preservation of renal function at day 30 (serum creatinine level, 1.38+/-0.8 mg/dl), compared with surviving animals treated with CsA alone (2.9+/-0.55 mg/dl, P<0.05). Histologic graft analysis of CsA/LMW-HA-treated animals at day 7 after transplantation showed minimal rejection and leukocyte infiltration, compared with all other groups. Intragraft gene expression analysis, using semiquantitative reverse transcription-PCR, at the same time point showed reductions of CD4, CD8, and interferon-gamma transcript levels in the combined-treatment group. This is the first study demonstrating the immunomodulatory functions of LMW-HA in vivo in the setting of organ transplantation. Defining the exact mechanisms that underlie this immunomodulation may provide the rationale to develop novel strategies for use in clinical transplantation.

Adjuvants, Immunologic↗
PubMed1999

In vitro and in vivo immunomodulatory effects of RDP1258, a novel synthetic peptide.

Peptides derived from certain regions of human class I MHC molecules are known to have immunomodulatory effects. In particular, amino acid residues 75-84 of the HLA-B7 and HLA-B2702 molecules have demonstrated allele nonspecific immunosuppression in several animal transplant models. There is evidence that these effects are mediated by binding to intracellular heat shock proteins, including heme oxygenase-1. A new derivative of these peptides, RDP1258, was developed using a novel computer-assisted rational design technique. In vitro, RDP1258 peptide inhibited rat heme oxygenase activity in a dose-dependent manner. Similar to observations made with other in vitro heme oxygenase inhibitors, in vivo administration of RDP1258 peptide to naive rats resulted in upregulation of splenic heme oxygenase activity. The effects of the peptide on alloimmune responses were then tested. Addition of RDP1258 to rat and human mixed leukocyte reactions inhibited proliferation in a dose-dependent manner. In a rat renal transplantation model, peptide therapy combined with a sub-therapeutic dose of cyclosporin A significantly prolonged allograft survival. These data provide further evidence that modulation of the heat shock protein heme oxygenase by rationally designed peptides affects immune effector functions and may allow the development of novel immunomodulatory strategies in organ transplantation.

Adjuvants, Immunologic↗
PubMed1999

FDG PET to evaluate combined intra-arterial chemotherapy and radiotherapy of head and neck neoplasms.

UNLABELLED: We evaluated the effectiveness of combined intra-arterial chemotherapy and radiotherapy on head and neck squamous cell carcinomas using fluorodeoxyglucose (FDG) PET. METHODS: Fifteen patients with squamous cell carcinoma of the head and neck were included in the study. Fourteen patients completed the treatment regimen and underwent FDG PET before and 4 wk after chemoradiotherapy. One patient underwent pretreatment FDG PET only. The pretreatment and post-treatment PET images were compared with clinical and histopathologic evaluations of the effects of chemoradiotherapy. For the quantitative evaluation of regional radioactivity, standardized uptake values (SUVs) with an uptake period of 50 min were used. RESULTS: Before treatment, FDG PET detected neoplasms in all 15 patients. The overall clinical response rate to chemoradiotherapy in the 14 patients who were imaged before and after treatment was 100%. Before treatment, the neoplastic lesions showed high SUVs (mean 7.77 mg/mL), which significantly decreased after therapy (3.62 mg/mL, P < 0.01). Lesions with higher pretreatment SUVs (> 7 mg/mL) showed residual viable tumor cells after the treatment in 3 of 8 patients, whereas those with lower SUVs (< 7 mg/mL, 6 patients) were successfully treated. Three of seven tumors with post-treatment SUVs > 4 mg/mL had viable tumor cells, whereas all tumors (7/7) with post-treatment SUVs < 4 mg/mL showed no viable cells. With concomitant chemoradiotherapy monitored by FDG PET, 5 patients avoided surgery entirely, and the remaining 9 patients underwent a reduced form of surgery. CONCLUSION: FDG PET is useful in evaluating the effects of combined chemotherapy and radiotherapy in patients with head and neck carcinoma. Pretreatment FDG PET is useful in predicting the response to treatment, and post-treatment FDG PET can evaluate residual viable cells. Hence, FDG PET is a valuable tool in the treatment of head and neck tumors.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1998

Marginal benefit/disadvantage of granulocyte colony-stimulating factor therapy after autologous blood stem cell transplantation in children: results of a prospective randomized trial. The Japanese Cooperative Study Group of PBSCT.

In this prospective trial, a total of 74 children who were scheduled to undergo high-dose chemotherapy followed by autologous peripheral blood stem cell transplantation (PBSCT) were prospectively randomized at diagnosis to evaluate the effectiveness of exogenous granulocyte colony-stimulating factor (G-CSF) treatment in accelerating hematopoietic recovery after PBSCT. The diagnosis included acute lymphoblastic leukemia (ALL) (n = 27), neuroblastoma (n = 29), and miscellaneous solid tumors (n = 18). Eligibility criteria included (1) primary PBSCT, (2) chemotherapy-responsive disease, and (3) collected cell number >1 x 10(5) colony-forming unit-granulocyte-macrophage (CFU-GM)/kg and >1 x 10(6) CD34(+) cells/kg patient's body weight. After applying the above criteria, 11 patients were excluded due to disease progression before PBSCT (n = 6) or a low number of harvested cells (n = 5), leaving 63 patients for analysis; 32 patients in the treatment group (300 microg/m2 of G-CSF intravenously over 1 hour from day 1 of PBSCT) and 31 in the control group without treatment. Two distinct disease-oriented high-dose regimens without total body irradiation consisted of the MCVAC regimen using ranimustine (MCNU, 450 mg/m2), cytosine arabinoside (16 g/m2), etoposide (1.6 g/m2), and cyclophosphamide (100 mg/kg) for patients with ALL, and the Hi-MEC regimen using melphalan (180 mg/m2), etoposide (1.6 g/m2), and carboplatinum (1.6 g/m2) for those with solid tumors. Five patients (two in the treatment group and three in the control group) were subsequently removed due to protocol violations. All patients survived PBSCT. The median numbers of transfused mononuclear cells (MNC), CD34(+) cells, and CFU-GM were, respectively, 4.5 (range, 1 to 19) x 10(8)/kg, 8.0 (1.1 to 25) x 10(6)/kg, and 3.7 (1.2 to 23) x 10(5)/kg in the treatment group (n = 30) and 2.9 (0.8 to 21) x 10(8)/kg, 6.3 (1.1 to 34) x 10(6)/kg, and 5.5 (1.3 to 37) x 10(5)/kg, respectively, in the control group (n = 28), with no significant difference. After PBSCT, the time to achieve an absolute neutrophil count (ANC) of >0.5 x 10(9)/L in the treatment group was less than that in the control group (median, 11 v 12 days; the log-rank test, P =.046), although the last day of red blood cell (RBC) transfusion (day 11 v day 10) and the duration of febrile days (>38 degrees C) after PBSCT (4 v 4 days) were identical in both groups. However, platelet recovery to >20 x 10(9)/L was significantly longer in treatment group than control group (26 v 16 days; P =.009) and >50 x 10(9)/L tended to take longer in the treatment group (29 v 26 days; P =.126), with significantly more platelet transfusion-dependent days (27 v 13 days; t-test, P =.037). When patients were divided into two different disease cohorts, ALL patients showed no difference in engraftment kinetics between the G-CSF treatment and control groups, while differences were seen in those with solid tumors. We concluded that the marginal clinical benefit of 1 day earlier recovery of granulocytes could be offset by the delayed recovery of platelets. We recommend that the routine application of costly G-CSF therapy in children undergoing PBSCT should be seriously reconsidered.

Adolescent↗
PubMed1998

Frequent aberration of FHIT gene expression in acute leukemias.

We analyzed the mRNA expression of the FHIT gene by reverse transcription-PCR (RT-PCR) in 54 cases of acute lymphoblastic leukemia (ALL; 11 cases of T-cell ALL [T-ALL] and 43 cases of non-T-ALL) and 40 cases of acute myeloid leukemia (AML). In 46% of the ALL cases and 55% of the AML cases, FHIT expression was absent or markedly decreased. Only abnormal short bands were detected in 30% of the ALL cases and 5% of the AML cases. Eighteen of 19 abnormal transcripts had the same fusion of exons 2-7, and all lacked the starting codon in exon 5. No obvious normal-sized PCR products were detected in cases exhibiting abnormal transcripts. These findings suggest that the expression of functional FHIT protein was lost in the majority of ALL (76%) and AML (60%) cases. Differential quantitative PCR of exons 3-9 of the FHIT gene and RT-PCR of the PTPRG gene, which is centromeric to the FHIT gene, showed the presence of the target sequences. Fluorescence in situ hybridization analysis using probes covering exons 5 and 8 revealed no difference in the signal patterns between leukemia and normal cells, showing one or two signal doublets in more than 90% of nuclei, and indicated that gross segments of the FHIT gene were not homozygously deleted in these cases. A small number of transcripts with an aberrant fusion between exons 2 and 7 were detected by RT-PCR in the bone marrow cells from four healthy individuals. Granulocytes, lymphocytes, and monocytes in the bone marrow cells of a healthy individual contained transcripts with the same fusion. This unique fusion of exons 2 and 7 might be preferentially seen in either neoplastic or normal hematopoietic cells, regardless of their lineage. The finding that FHIT expression was abolished in the majority of leukemia cases might support the hypothesis that the FHIT gene acts as a tumor suppressor, at least in leukemia.

Acid Anhydride Hydrolases↗
PubMed1998

Late blockade of T cell costimulation interrupts progression of experimental chronic allograft rejection.

Early blockade of T cell-costimulatory activation pathways prevents development of experimental chronic allograft rejection. Ongoing T cell recognition of alloantigen and activation may also play an important role in progression of chronic rejection, but definitive evidence is lacking. We used the fusion protein CTLA4Ig to block CD28-B7 T cell costimulation late after the onset of initial graft injury. Using the F334 into LEW rat model of chronic renal allograft rejection, transplant recipients were treated with a 10-d course of cyclosporine, and a subgroup received a single injection of CTLA4Ig at 8 wk after transplant. Functionally, CTLA4Ig administration prevented development of progressive proteinuria (14.3+/-4.1 mg/24 h versus 41.0+/-12.0 mg/24 h at 24 wk after transplant, P < 0.05). Histologically, graft mononuclear cell infiltration, glomerular hypertrophy, focal and segmental glomerulosclerosis, and intimal vascular hyperplasia were all attenuated in CTLA4Ig-treated animals. Lastly, reverse transcriptase-PCR and immunohistologic studies showed a significant reduction in the intragraft expression of key products of T cell and macrophage activation, and upregulation of what have recently been termed as "protective" genes, including the bcl family members, Bcl-2 and Bcl-xL, and hemoxygenase. Our data are the first to demonstrate that blocking T cell-costimulatory activation late after transplantation, after initial graft injury, prevents progression of chronic allograft rejection supporting the hypothesis that ongoing T cell recognition of alloantigen and activation are key mediators of ongoing chronic allograft rejection.

Abatacept↗
PubMed1998

HRG Tokushima: molecular and cellular characterization of histidine-rich glycoprotein (HRG) deficiency.

Previously, we found the first congenital deficiency of histidine-rich glycoprotein (HRG) in a Japanese woman with thrombosis. To elucidate the genetic basis of this deficiency, we first performed Southern blot analysis and found no gross deletion or insertion in the proband's HRG gene. We then examined the nucleotide sequences of all seven exons of the proband's HRG gene. A single nucleotide substitution, G to A at nucleotide position 429, which mutates Gly85 to Glu in the first cystatin-like domain, was found in exon 3 in 13 of 22 amplified clones. This mutation generates a unique Taq I site. Exon 3 was amplified from the proband, her family members, and 50 unrelated normal Japanese individuals, and Taq I fragmentation was examined. Fragmentation of exon 3 was observed in one allele of the genes from the proband and the family members who also have decreased plasma levels of HRG. Fifty unrelated normal Japanese individuals had a normal HRG gene, indicating that the G to A mutation is not a common polymorphism. To elucidate the identified mutation as a cause for the secretion defect of HRG in the proband's plasma, we constructed and transiently expressed the recombinant Tokushima-type HRG mutant (Gly85 to Glu) in baby hamster kidney (BHK) cells, and examined an intracellular event of the mutant protein. The results showed that only about 20% of the Tokushima-type HRG was secreted into the culture medium, and intracellular degradation of the mutant was observed. Thus, the present study strongly suggests that the HRG deficiency is caused by intracellular degradation of the Gly85 to Glu mutant of HRG in the proband.

Adult↗
PubMed1998

Nitric oxide relaxes bovine ciliary muscle contracted by carbachol through elevation of cyclic GMP.

It is generally accepted that nitric oxide relaxes vascular smooth muscles by activating guanylyl cyclase, which in turn increases cyclic 3':5' guanosine monophosphate level. Despite the physiological significance of nitric oxide, very few studies have attempted to characterize the mode of action of this mediator in ciliary muscles. Therefore, the present experiments were designed to investigate whether or not the relaxation induced by sodium nitroprusside as a donor of nitric oxide is accompanied by the increase in cyclic 3':5' guanosine monophosphate level in the bovine ciliary muscle, and these responses are affected by methylene blue as an inhibitor of guanylyl cyclase and 3-isobutyl-1-methylxanthine as an inhibitor of phosphodiesterases. The relaxation activity of exogenous 8-bromo-cyclic 3':5' guanosine monophosphate was also determined. Sodium nitroprusside produced a concentration-dependent relaxation in the bovine ciliary muscle strips which had been contracted by carbachol as a cholinergic agonist. Relaxation in response to sodium nitroprusside was accompanied by a significant (P<0.05 and P<0.005) increase in cyclic 3':5' guanosine monophosphate level. The relaxation response and the increase in cyclic 3':5' guanosine monophosphate caused by sodium nitroprusside were significantly (P<0.01 and P<0.05) augmented by the pretreatment with 3-isobutyl-1-methylxanthine, and were significantly (P<0.005 and P<0.05) attenuated in the presence of methylene blue. The exogenously applied 8-bromo-cyclic 3':5' guanosine monophosphate relaxed the ciliary muscle strips in a concentration-dependent manner. These results suggest that nitric oxide causes relaxation of the bovine ciliary muscle through the activation of guanylyl cyclase and an increase in cyclic 3':5' guanosine monophosphate level.

1-Methyl-3-isobutylxanthine↗
PubMed1998

Immunolocalization of matrix metalloproteinases in rabbit carotid arteries after balloon denudation.

Extracellular matrix-degrading enzymes may play a key role in vascular remodeling after arterial wall injury. We investigated the immunolocalization of matrix metalloproteinases (MMPs) in rabbit carotid arteries after balloon denudation. Positive immunostaining for MMP-1, -2, -3, and -9 appeared through the neointima 1 week after balloon denudation. The localization of immunopositive smooth muscle cells (SMCs) for MMP- 1, -3, and -9, particularly for MMP-9, was almost similar to that of replicative SMCs and became confined to the luminal surface layer of the neointima at later time periods. However, MMP-2-positive SMCs appeared also in the basal layer of the neointima at 2 weeks, increased at 4 weeks, and then totally occupied the neointima at 6 weeks. The MMP-2-positive SMCs in the basal layer of the neointima at 4 and 6 weeks were negative for proliferation-associated antigens and were surrounded by extracellular matrix proteins. Our results suggest that all MMPs act in coordination to promote replication and migration of SMCs in the earlier phases of neointimal formation and that MMP-2 independently contributes to the later stages by facilitating the migration but not replication of SMCs from the media to the intima.

Animals↗