Biomedical subjects

A Tojo

Publications and source records attributed to A Tojo.

At least 37 records · Page 2Linked to original sources

PubMed2000

TCR-Vbeta repertoire analysis with RT-PCR was useful for the early detection of pulmonary relapsed T-cell lymphoma after autologous peripheral blood stem cell transplantation.

Pulmonary recurrence of malignant lymphoma is a rare event after stem cell transplantation. We report here a 45-year-old male who was successfully diagnosed with relapsed pulmonary T-cell lymphoma using an RT-PCR method. Clonal expansion of T cells expressing identical TCR V-D-J junction size (Vbeta5-Jbeta1.5) was demonstrated in lymphocyte groups obtained from both bronchoalveolar lavage fluid at relapse, and paraffin embedded lymph node samples resected when he was first diagnosed with angioimmunoblastic T-cell lymphoma. This method provided evidence to diagnose relapsed pulmonary angioimmunoblastic T-cell lymphoma in its early phase.

Bronchoalveolar Lavage Fluid↗

PubMed2000

Progress reports on immune gene therapy for stage IV renal cell cancer using lethally irradiated granulocyte-macrophage colony-stimulating factor-transduced autologous renal cancer cells.

There is no effective treatment for patients with stage IV renal cell cancer (RCC), although the introduction of new therapy is imminent. Cancer gene therapy is currently considered to be one of the most promising therapeutic modalities in the field of cancer treatment. Based on the results of animal studies, vaccination using autologous granulocyte-macrophage colony-stimulating factor-transduced renal cancer cells appears promising. Before initiating a clinical study using an ex vivo gene-transduced autologous cell vaccine-based immunogene therapy for RCC in Japan, in 1992 we initially planned a Japanese version of a clinical protocol in collaboration with a US group. In 1993, the original protocol was refined. We performed five preclinical qualification studies using RCC nephrectomy specimens from patients in 1997, and the results showed that preparation of RCC cells for autologous vaccines at the Clinical Cell Technology Facility, Research Hospital of the Institute of Medical Science, University of Tokyo, was feasible. Subsequently in August 1998, the Ministry of Health and Welfare and the Ministry of Education, Science, Culture, and Sport approved our clinical protocol. We have recruited two patients with stage IV RCC to our study so far. Here we report the background to the initiation of cancer gene therapy in Japan.

Adult↗

PubMed2000

MHC (major histocompatibility complex)-DRB genes and polymorphisms in common marmoset.

A New World monkey, the common marmoset (Callithrix jacchus), will be used as a preclinical animal model to study the feasibility of cell and gene therapy targeting immunological and hematological disorders. For elucidating the immunogenetic background of common marmoset to further studies, in the present study, polymorphisms of MHC-DRB genes in this species were examined. Twenty-one Caja-DRB exon 2 alleles, including seven new ones, were detected by means of subcloning and the polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) methods followed by nucleotide sequencing. Based on the alignment of these allele sequences, we designed two pairs of specific primers and established a PCR-SSCP method for DNA-based histocompatibility typing of the common marmoset. According to the family segregation data and phylogenetic analyses, we presumed that Caja-DRB alleles could be classified into five different loci. Southern blotting analysis also supported the existence of multiple DRB loci. The patterns of nucleotide substitutions suggests that positive selection operates in the antigen-recognition sites of Caja-DRB genes.

Alleles↗

PubMed2000

The effect of granulocyte colony-stimulating factor administration in healthy donors before bone marrow harvesting.

To investigate whether granulocyte colony-stimulating factor (G-CSF) administration to donors before harvest may lighten the burden imposed on them and accelerate the bone marrow (BM) recovery, we administered 2 microgram/kg/d of G-CSF for five consecutive days before the marrow harvest. All of the donors tolerated the G-CSF administration well without severe adverse events. After 5 d of G-CSF treatment, CD34+ cells and granulocyte-macrophage colony-forming units (GM-CFU) in the donors' BM exceeded baseline values by 4.2-fold (range 0.71-316) and 1.6-fold (0.28-118) respectively. The concentration of total nucleated cells (x 107/ml) in the graft increased from 1.61 (0.95-3.23) to 2.44 (1.27-4.01). Although we collected 1020 ml of BM and obtained 1.50 x 1010 nucleated cells from unprimed donors, 940 ml of BM were sufficient to obtain 2.14 x 1010 nucleated cells from primed donors. However, G-CSF-primed BM did not shorten the time to tri-lineage engraftment and the duration of hospitalization compared with unprimed BM, although primed BM contained more CD34+ cells than baseline values. We consider that the advantages of BM priming are not the acceleration of BM recovery but rather the reduction of blood loss during BM harvesting.

Adolescent↗

PubMed2000

Developmental changes in multispecific organic anion transporter 1 expression in the rat kidney.

BACKGROUND: The cDNA of the multispecific organic anion transporter 1 (OAT1) responsible for the tubular secretion of organic anions was recently isolated. In the current study, we investigated the developmental changes in OAT1 expression in the rat kidney. METHODS: Ontogenic expression of rat OAT1 was investigated by Northern blot, in situ hybridization, Western blot, and immunohistochemical analysis. In addition, para-aminohippurate (PAH) accumulation was measured using fetal, neonatal, and adult rat kidney slices. RESULTS: In Northern blot analysis, OAT1 was detected as early as on embryonic day 18 in the fetal kidney. The expression level of OAT1 mRNA increased remarkably just after birth (postnatal day 0). In situ hybridization revealed OAT1 expression on embryonic day 19. In both the fetal and neonatal kidneys, OAT1 mRNA was localized in a relatively deep region in the cortex. Western blot analysis detected OAT1 protein on embryonic day 20, and the expression level increased after birth. Immunohistochemical analysis did not reveal OAT1 staining in the fetal kidneys. A faint signal of OAT1 protein was detected on postnatal day 0; thereafter, the expression level increased. In the functional study using kidney slices, low but definite probenecid-sensitive PAH accumulation was noted in fetal rat kidney on embryonic day 20. After birth, probenecid-sensitive PAH uptake was increased. CONCLUSIONS: The present study consistently demonstrates the remarkable increase of OAT1 expression after birth, and the immature excretory capacity of the proximal tubules of the neonatal kidney can be attributed, at least in part, to the low expression level of OAT1.

Aging↗

PubMed2000

Renal expression of constitutive NOS and DDAH: separate effects of salt intake and angiotensin.

BACKGROUND: Nitric oxide (NO) is generated from NO synthase (NOS) isoforms. These enzymes can be inhibited by asymmetric dimethylarginine, which is inactivated by N(G)-N(G)-dimethylarginine dimethylaminohydrolase (DDAH). The neuroneal (nNOS) type I and endothelial (eNOS) type III constitutive NOS isoforms are expressed predominantly in the macula densa and microvascular endothelium of the renal cortex, respectively. DDAH is expressed at sites of NOS expression. Since NO may coordinate the renal responses to angiotensin II (Ang II) and changes in salt intake, we tested the hypothesis that salt intake regulates the expression of nNOS, eNOS and DDAH by Ang II acting on type 1 (AT(1)) receptors. METHODS: Groups (N = 6) of rats were adapted to low-salt (LS) or high-salt (HS) intakes for 10 days. Other groups of LS and HS rats received the AT(1) receptor antagonist losartan for six days (to test the effects of salt independent of AT(1) receptors). A further group of HS rats received an infusion of Ang II for six days (to test the effect of Ang II independent of salt intake). RESULTS: Compared with HS rats, there was a significant (P < 0.05) increase in LS rats of nNOS protein in kidney and immunohistochemical expression in the macula densa, and of eNOS protein expression and immunohistochemical expression in the microvascular endothelium, and of DDAH protein expression. Losartan prevented these effects of salt on the expression of eNOS or DDAH, both of which were also increased by Ang II infusions in HS rats. In contrast, losartan did not prevent the effects of salt on nNOS expression, which was unresponsive to Ang II infusion. The generation of NO(2)(-) released by slices of renal cortex, in the presence of saturating concentrations of L-arginine, was increased by LS, compared to HS, independent of losartan and by Ang II during HS. CONCLUSION: The expressions of eNOS in cortical microvascular endothelium and DDAH in kidney are enhanced by Ang II acting on AT(1) receptors. The expression of nNOS in the macula densa is enhanced by salt restriction independent of Ang II or AT(1) receptors.

Amidohydrolases↗

PubMed2000

Roles of NO and oxygen radicals in tubuloglomerular feedback in SHR.

The spontaneously hypertensive rat (SHR) has enhanced tubuloglomerular feedback (TGF) responses and diminished buffering by juxtaglomerular apparatus (JGA)-derived nitric oxide (NO) despite enhanced expression of NO synthase (NOS) isoforms in the JGA. We tested the hypothesis that the enhanced TGF response is due to inactivation of NO by oxygen radicals (O(-)(2)). SHR had significantly (P<0.05) greater expression of the peroxynitrate reaction product, nitrotyrosine, in renal cortex. A membrane-permeant, metal-independent superoxide dismutase mimetic, tempol, was used to test the functional role of O(-)(2). Maximum TGF responses, assessed from changes in proximal stop-flow pressure (P(SF)) during orthograde loop of Henle (LH) perfusion of artificial tubular fluid (ATF), were enhanced in SHR [Wistar-Kyoto rat (WKY) 8.8+/-0.4 (n = 30 nephrons) vs. SHR 10.8+/-0.4 mm Hg (n = 39 nephrons), P<0.001]. TGF responses of SHR were unresponsive to microperfusion of 7-nitroindazole (7-NI, 10(-4) M), which is an inhibitor of neuronal NOS (nNOS) [WKY 8.3+/-0.3 to 10.8+/-0.4 (n = 8, P<0.001) vs. SHR 10.0+/-0.7 to 10.5+/-0.8 mm Hg (n = 8; not significant)]. Microperfusion of tempol (10(-4) M) into the efferent arteriole (EA) supplying the peritubular capillaries (PTC) blunted TGF. The response to tempol was significantly (P< 0.05) greater in SHR [DeltaTGF in WKY 19+/-6% (n = 10) vs. SHR 32+/-3% (n = 10)]. Microperfusion of the NO donor compound S-nitroso-N-acetyl-penicillamine (SNAP, 10(-7)-10(-4) M) via the LH blunted TGF, but the sensitivity of the response was impaired significantly (P<0.05) in SHR nephrons. PTC perfusion of tempol (10(-4) M) normalized the response to loop perfusion of both SNAP and 7-NI in SHR nephron to levels in WKY (during tempol, DeltaP(SF) with 7-NI in WKY 8.9+/-0.6 to 11.4+/-0.8; n = 12 vs. SHR 9.5+/-0.5 to 12.5+/-0.4 mm Hg; n = 16). In conclusion, TGF responses are enhanced in SHR, in part due to a diminished role for NO from nNOS in blunting TGF due to enhanced O(-)(2) formation. O(-)(2) in the JGA enhances TGF responses by inactivation of locally generated NO.

Animals↗

PubMed2000

Refractory facial cellulitis following cosmetic rhinoplasty after cord-blood stem cell transplantation.

We report a case of a 38-year-old female patient who developed facial cellulitis after cord-blood stem cell transplantation (CBT). The cellulitis was refractory to treatment with antibiotics and antifungal agents. Because facial cellulitis is rare after transplantation, its mechanism could not be determined exactly. On day 40 after CBT, a nurse with expertise in cosmetic surgery attended our rounds and correctly assumed that the patient had received cosmetic rhinoplasty. Although conventional x-rays of the head were normal, a computed tomographic (CT) scan of the brain disclosed the presence of a foreign body over the nasal dorsum. As a result, the patient's symptoms were diagnosed as facial cellulitis associated with foreign material that had been implanted at the time of cosmetic surgery. At a pretransplantation interview, the patient did not mention her history of rhinoplasty. Even after she was shown the head CT scans that revealed the presence of nasal implants, she denied that she had received rhinoplasty before CBT. Unless we realize that patients may have received cosmetic surgery before transplantation, it is difficult to make a diagnosis of infection associated with foreign implants. To our knowledge this is the first report after transplantation of infection associated with cosmetic surgery. Such infections should be included on the list of complications after bone marrow transplantation.

Adult↗

PubMed1999

Regulation by 1alpha,25-dihydroxyvitamin D(3) of expression of stanniocalcin messages in the rat kidney and ovary.

Regulation by vitamin D(3) of expression of the genes for stanniocalcins 1 and 2 (STC-1 and STC-2) was studied and their levels were shown to be oppositely regulated in the kidney and to remain unaffected in the ovary. Female rats were treated with calcitriol, the active form of vitamin D(3), and alterations in the levels of STC-1 and STC-2 mRNA were determined by Northern blot analysis in the kidney and ovary where the STC-1-expressing cells have previously been identified by in situ hybridization histochemistry. In the kidney, calcitriol treatment increased the STC-1 mRNA levels more than 3-fold, but decreased the STC-2 message to trace levels. In the ovary, however, both STC-1 and STC-2 mRNA levels were not significantly affected by the calcitriol treatment. These results support the hypotheses that (1) STC-1 and STC-2 have opposite effects on calcium and phosphate homeostasis, namely anti-hypercalcemic and anti-hypocalcemic actions, respectively, and (2) the mammalian stanniocalcin system acquired, in addition to the role in the systemic mineral metabolism, a role in the reproduction system that operates independently of the systemic condition.

Animals↗

PubMed1999

The common marmoset as a target preclinical primate model for cytokine and gene therapy studies.

Nonhuman primate models are useful to evaluate the safety and efficacy of new therapeutic modalities, including gene therapy, before the inititation of clinical trials in humans. With the aim of establishing safe and effective approaches to therapeutic gene transfer, we have been focusing on a small New World monkey, the common marmoset, as a target preclinical model. This animal is relatively inexpensive and easy to breed in limited space. First, we characterized marmoset blood and bone marrow progenitor cells (BMPCs) and showed that human cytokines were effective to maintain and stimulate in culture. We then examined their susceptibility to transduction by retroviral vectors. In a mixed culture system containing both marmoset stromal cells and retroviral producer cells, the transduction efficiency into BMPCs and peripheral blood progenitor cells (PBPCs) was 12% to 24%. A series of marmosets then underwent transplantation with autologous PBPCs transduced with a retroviral vector carrying the multidrug resistance 1 gene (MDR1) and were followed for the persistence of these cells in vivo. Proviral DNA was detectable by polymerase chain reaction (PCR) in peripheral blood granulocytes and lymphocytes in the recipients of gene transduced progenitors up to 400 days posttransplantation. To examine the function of the MDR1 gene in vivo, recipient maromsets were challenged with docetaxel, an MDR effluxed drug, yet the overall level of gene transfer attained in vivo (<1% in peripheral blood granulocytes) was not sufficient to prevent the neutropenia induced by docetaxel treatment. Using this model, we safely and easily performed a series of in vivo studies in our small animal center. Our results show that this small nonhuman primate, the common marmoset, is a useful model for the evaluation of gene transfer methods targeting hematopoietic stem cells.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1999

Effects of hypertension, diabetes mellitus, and hypercholesterolemia on endothelin type B receptor-mediated nitric oxide release from rat kidney.

BACKGROUND: Although endothelin-1 is a potent vasoconstrictor peptide, stimulation of endothelin type B receptor (ETBR) causes bidirectional changes in vascular tone, ie, vasodilation and vasoconstriction. Roles of ETBR in pathological conditions are largely unknown. METHODS AND RESULTS: We studied the effect of BQ-3020, a highly selective ETBR agonist, on renal vascular resistance and nitric oxide (NO) release in the isolated, perfused kidney of rats with hypertension, diabetes mellitus, and hypercholesterolemia. Immunohistochemistry of endothelial NO synthase and ETBR was also examined. Infusion of BQ-3020 at concentrations of </=10(-10) mol/L reduced renal perfusion pressure in Dahl salt-resistant (R) rats but increased renal perfusion pressure in Dahl salt-sensitive (S) rats (10(-10) mol/L: -10.3+/-0. 6% versus 11.2+/-1.5%, R versus S; P<0.01). BQ-3020 caused a dose-dependent release of NO in both R and S rats, although the level of NO release in S rats was lower, as detected by chemiluminescence (10(-10) mol/L: 10.7+/-0.7 versus 3.1+/-0.4 fmol/min per gram of kidney, R versus S; P<0.01). Similar effects of BQ-3020 were observed in streptozotocin-induced diabetic rats and diet-induced hypercholesterolemic rats. Expression of endothelial NO synthase decreased in S rats but not in diabetic or hypercholesterolemic rats. In contrast, expression of ETBR in the endothelium was decreased in all 3 disease models compared with that in the vascular smooth muscle cell. CONCLUSIONS: These results suggest that impaired NO release in response to stimulation of ETBR is due, at least in part, to a decrease in endothelial ETBR and may play a role in vascular dysfunction usually associated with arteriosclerosis-related diseases.

Animals↗

PubMed1999

Fusion of ETV6 to neurotrophin-3 receptor TRKC in acute myeloid leukemia with t(12;15)(p13;q25).

Chromosome translocations involving band 12p13 are known to be involved in a variety of hematologic malignancies, some of them resulting in rearrangement of the ETV6/TEL gene. Applying the fluorescence in situ hybridization (FISH) method, we found a cryptic translocation t(12;15)(p13;q25) in an adult acute myeloid leukemia (AML) patient. Hybridization with cosmid probes showed that the ETV6 gene was rearranged in this translocation. A patient-specific cDNA library was screened with ETV6 cDNA, and a novel fusion transcript was identified between the ETV6 and TRKC/NTRK3 gene located on 15q25. TRKC is a receptor tyrosine kinase that is activated by neurotrophin-3 (NT-3). It is known to be expressed broadly in neural tissues but not in hematologic cells, so far. ETV6-TRKC chimeric transcript encoded the pointed (PNT) domain of the ETV6 gene that fused to the protein-tyrosine kinase (PTK) domain of the TRKC gene. Two types of fusion transcript were determined, one that included the entire PTK domain of TRKC and the other in which the 3'-terminal 462 bp of TRKC was truncated within the PTK domain. Western blot analysis showed the expression of both chimeric proteins of 52 and 38 kD in size. Our results suggest that chimeric PTK expressed in the leukemic cells may contribute to cellular transformation by abnormally activating TRK signaling pathways. Moreover, this is the first report on truncated neurotrophin receptors associated in leukemia.

Acute Disease↗

PubMed1999

Significant expression of G-CSF-induced gene-1 (GIG-1) protein in myeloid cells and NK cells.

The granulocyte colony-stimulating factor (G-CSF)-induced gene, GIG-1, was originally cloned from G-CSF-stimulated bone marrow mononuclear cells obtained from a patient with chronic myelogenous leukemia (CML). We have characterized the GIG-1 gene and its protein product. Expression of GIG-1 mRNA was elevated by treatment with G-CSF in normal bone marrow mononuclear cells, as well as in some cases of blast cells obtained from patients with acute myelogenous leukemia (AML) and CML. Western blot analysis with anti-GIG-1 peptide antiserum showed the molecular mass of GIG-1 product was about 17 kDa. Immunostaining of the hematopoietic cells demonstrated that GIG-1 product was mainly localized to the cytoplasm of both myeloid and natural killer (NK) cells. These results suggested that GIG-1 protein is an integral component that is accumulated during the differentiation of myeloid cells toward the stage of mature neutrophils. Expression of GIG-1 gene in mature neutrophils was tightly regulated and reactivation of GIG-1 gene by G-CSF in mature neutrophils may represent a compensation process for the protein lost through the activation of these cells, thus implying an important role for this protein in host defense mechanisms.

Antigens, CD34↗

PubMed1999

IL-2/LAK therapy for refractory acute monoblastic leukemia relapsing after unrelated allogeneic bone marrow transplantation.

Leukemia relapse is a major cause of treatment failure after allogeneic bone marrow transplantation. We administered recombinant interleukin-2 (rIL-2) to a patient who relapsed after unrelated allogeneic bone marrow transplantation (uBMT). While the number of peripheral blood monoblastic leukemia cells increased after administration of rIL-2, the patient achieved durable remission for 5 months after low-dose chemotherapy followed by adoptive transfer of engrafted graft-derived lymphokine-activated killer (LAK) cells. Following the disappearance of the blast cells, however, both cutaneous and liver GVHD were exacerbated. Administration of rIL-2 and adoptive transfer of graft-derived LAK cells are considered to be possible choices for the treatment of acute leukemia relapsing after uBMT when donor leukocyte transfusion is not available.

Adjuvants, Immunologic↗

PubMed1999

Distribution of postsynaptic density proteins in rat kidney: relationship to neuronal nitric oxide synthase.

BACKGROUND: Neuronal nitric oxide synthase (nNOS) is expressed in skeletal muscle beneath the sarcolemma associated with dystrophin complex. In brain, nNOS is anchored to synaptic membranes by specific postsynaptic density proteins (PSD)-95 and PSD-93. We have investigated the cellular and subcellular localization of these PSD proteins in the kidney and their relationship to nNOS and the cell membrane. METHODS: Kidneys from male Sprague-Dawley rats were processed for light and electron microscopic immunohistochemistry with polyclonal antibodies against PSD and nNOS proteins. RESULTS: Western blot analysis of rat kidney revealed a specific band for PSD-93 at the molecular weight of 103 kDa. Immunostaining for PSD-93 was located in the thick ascending limb of the loop of Henle, macula densa cells, distal convoluted tubules, cortical collecting ducts, outer and inner medullary collecting duct, glomerular epithelium, and Bowman's capsule. A pre-embedding electron microscopic immunoperoxidase procedure localized PSD-93 to the basolateral membrane of these tubular cells. Using different sized immunogold particles, a portion of nNOS in the macula densa colocalized with PSD-93 adjacent to cytoplasmic vesicles and the basolateral membrane. In contrast, PSD-95 protein was detected only weakly in the cortex by Western blot. Immunostaining for PSD-95 was located only faintly in the apical membrane of the thick ascending limb, macula densa, distal convoluted tubule and cortical collecting duct cells. CONCLUSION: PSD-93 is the predominant PSD expressed in the rat kidney. It is located primarily in the basolateral membranes of distal nephron and colocalizes with a pool of nNOS in cytoplasmic vesicles and basolateral membranes of macula densa cells.

Animals↗

PubMed1999

Role of organic anion transporter 1 (OAT1) in cephaloridine (CER)-induced nephrotoxicity.

UNLABELLED: Role of organic anion transporter 1 (OAT1) in cephaloridine (CER)-induced nephrotoxicity. BACKGROUND: Cephaloridine (CER) has been used to elucidate the mechanisms of cephalosporin antibiotic-induced nephrotoxicity. Organic anion transporters have been thought to mediate CER uptake by the proximal tubule. The purpose of this study was to elucidate the possible involvement of organic anion transporter 1 (OAT1) in CER-induced nephrotoxicity. METHODS: A mouse terminal proximal straight tubule (S3) cell line stably expressing rat OAT1 (S3 rOAT1) was established and used in this study. The cellular uptake of [14C]-para-aminohippuric acid (PAH), a prototype organic anion, and that of [14C]-CER were measured. The effects of CER on the viability of the cells and the amount of lipid peroxidation were estimated. RESULTS: S3 rOAT1 expressed a functional organic anion transporter in the cytoplasmic membrane, and exhibited CER uptake activity. CER treatment resulted in a more significant decrease in the viability and a more significant increase in the amount of lipid peroxidation in S3 rOAT1 than in S3 cells transfected with an expression vector lacking the rOAT1 insert. Probenecid, an inhibitor of organic anion transport, and probucol, an antioxidant, significantly suppressed the decrease in viability and increase in the amount of lipid peroxidation in S3 rOAT1 treated with CER. The effects of various cephalosporin antibiotics on the uptake of [14C]PAH were correlated significantly with the effects of these drugs on cell viability. CONCLUSIONS: These results suggest that rOAT1 is, at least in part, responsible for the cellular uptake of CER and therefore CER-induced nephrotoxicity.

Animals↗

PubMed1999

Effects of amlodipine on nitric oxide synthase mRNA expression and coronary microcirculation in prolonged nitric oxide blockade-induced hypertensive rats.

We evaluated the effects of long-term treatment with amlodipine, a calcium antagonist, on nitric oxide synthase (NOS) activity and NOS messenger RNA (mRNA) expression in the left ventricle (LV) and its relation to coronary reserve, and microvascular remodeling in Nomega-nitro-L-arginine methyl ester (L-NAME)-induced hypertensive rats. Seventeen male Sprague-Dawley rats were given L-NAME (60 mg/kg/day) in drinking water for 6 weeks to induce hypertension, and then treated with amlodipine (L-NAME + A, 5 mg/kg/day, n = 9), or a vehicle (L-NAME + V, n = 8) for 4 weeks. Age-matched rats (C, n = 8) served as the control group. An increased blood pressure in L-NAME + V was significantly decreased in L-NAME + A. Nitrite production and endothelial cell (e) NOS mRNA in the LV were significantly decreased in L-NAME + V compared with C, and were significantly increased in L-NAME + A compared with C and L-NAME + V. L-NAME + V had a significantly decreased coronary reserve and capillary density, and a significantly increased type I collagen mRNA expression, wall-to-lumen ratio, perivascular fibrosis, myocardial fibrosis, and myocyte cross-sectional area. These parameters in the microvasculature were significantly improved by amlodipine. We concluded that NOS activity and eNOS mRNA were significantly increased by amlodipine in the LV of L-NAME-induced hypertensive rats, and that these increase NOS activity and eNOS mRNA expression may play a role in the amelioration of coronary reserve and microvascular remodeling.

Amlodipine↗

PubMed1999

Nitric oxide synthase in the JGA of the SHR: expression and role in tubuloglomerular feedback.

The spontaneously hypertensive rat (SHR) has an enhanced tubuloglomerular feedback (TGF) and a diminished buffering by juxtaglomerular apparatus (JGA)-derived NO. We examined the hypothesis that these effects are due to decreases in nitric oxide synthase (NOS) expression or limited availability of L-arginine or tetrahydrobiopterin (BH(4)). SHR had significantly (P < 0.05) greater mRNA abundance (by RT-PCR) or protein (by Western analysis) for neuronal NOS (nNOS, or type I) and endothelial cell NOS (ecNOS, or type III) in renal cortex or isolated glomeruli, respectively. There was prominent expression of ecNOS in glomerular endothelium and nNOS in macula densa. Maximal TGF responses, assessed from changes in proximal stop-flow pressure during orthograde loop of Henle (LH) perfusion, were greater in SHR [Wistar-Kyoto (WKY), 8.1 +/- 0.3 (n = 46) vs. SHR, 10.3 +/- 0.3 mmHg (n = 57); P < 0.001]. Unlike WKY, TGF responses of SHR were unresponsive to microperfusion of the nNOS inhibitor, 7-nitroindazole (7-NI, 10(-4) M) [WKY, 9.5 +/- 0.5 to 13.2 +/- 0.7 (n = 13, P < 0.001) vs. SHR, 11.8 +/- 0.7 to 12.5 +/- 0.6 mmHg (n = 19, not significant)], or to L-arginine (10(-3) M) [WKY, 7.7 +/- 0.8 to 6.3 +/- 0.4 (n = 10, P < 0.05) vs. SHR, 10.4 +/- 0.7 to 10.6 +/- 0.7 mmHg (n = 10, not significant)]. Neither BH(4) (10(-4) M) nor sepiapterin (10(-4) M), its stable precursor, modified TGF responses in WKY or in SHR, nor did they restore a response to microperfusion of 7-NI in SHR. In conclusion, there is a diminished role for NO from nNOS in blunting of TGF in SHR which cannot be ascribed to limited NOS expression or availability of substrate or BH(4).

Animals↗