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Biomedical subjects

K B Miller

Publications and source records attributed to K B Miller.

At least 37 records · Page 2Linked to original sources
PubMed1999

The association of interleukin 6 with clinical and laboratory parameters of acute pelvic inflammatory disease.

OBJECTIVE: We sought (1) to determine whether interleukin 6 levels are increased in plasma and cervical secretions and endometrial tissue obtained from women with a clinical diagnosis of pelvic inflammatory disease, (2) to determine whether interleukin 6 levels in these sample sites reflected the clinical severity of acute infection, and (3) to determine whether interleukin 6 levels in endometrial tissue obtained from these women were higher in the presence of histologic endometritis. STUDY DESIGN: We performed a prospective pilot study on 20 women with a clinical diagnosis of pelvic inflammatory disease (patients) and then compared them with 20 women presenting to the gynecology clinic without pelvic complaints (control subjects). Interleukin 6 levels were measured by enzyme-linked immunologic testing in plasma, cervical secretions, and endometrial biopsy specimens. RESULTS: Cervical interleukin 6 levels were higher in patients than control subjects (median, 317 vs 111 pg/mL; P =.003). Among women with pelvic inflammatory disease, statistically significant positive correlations were noted between the clinical severity score and the erythrocyte sedimentation rate (r = 0.45; P =.04), the clinical severity score and the white blood cell count (r = 0.49; P =.03), the plasma interleukin 6 levels and the erythrocyte sedimentation rate (r = 0.55; P =.02), and the plasma interleukin 6 levels and the white blood cell count (r = 0.54, P =.01). Endometrial tissue interleukin 6 levels were also higher in patients with versus those without histologic endometritis (median, 427 vs 17 pg/mL; P =.004). CONCLUSION: In this pilot study interleukin 6 levels in cervical secretions were significantly higher in women with pelvic inflammatory disease versus those without pelvic inflammatory disease. In women with pelvic inflammatory disease, endometrial tissue samples with histologic evidence of endometritis were observed to have higher levels of interleukin 6. Interleukin 6 may be a useful adjunct to the clinical diagnosis of pelvic inflammatory disease.

Acute Disease↗
PubMed1999

Catastrophic hemorrhage on sternal reentry: still a dreaded complication?

BACKGROUND: To define the incidence of catastrophic hemorrhage (CH) during reoperations, the experience of the University of New Mexico was reviewed and compared with the practice of surgeons contacted by questionnaire. METHODS: At the University of New Mexico, 610 reoperations were reviewed and 210 deemed high risk because of multiple reoperation, aneurysm, patent grafts, chamber's enlargement, conduit or previous mediastinitis. In the questionnaire, we asked about reentry technique, occurrence and outcome of CH, and precautions for high-risk patients. RESULTS: At the University of New Mexico there were 4 CH with 1 death, and in the questionnaire there were 2,046 CH with 392 deaths. Our rate per surgeon was lower than that of the questionnaire. Rate of CH according to the saw was 2.09 for reciprocating, 2.0 for sagittal, and 1.74 for stryker in the questionnaire. Our rate was lower (0.65) with a micro sagittal saw. High-risk category predicted CH during sternotomy (p = 0.01) but only conduit (p = 0.005) was significant by univariate analysis. CONCLUSIONS: The risk of CH could be as high as 1%. The sagittal micro oscillating saw is the safest reported to date. Presence of a conduit increases the risk by 2.5 fold.

Adolescent↗
PubMed1999

Role of splenic irradiation in patients with chronic myeloid leukemia undergoing allogeneic bone marrow transplantation.

Allogeneic bone marrow transplantation (BMT) has become the treatment of choice for patients of appropriate age with chronic myeloid leukemia (CML). In an attempt to enhance tumor cytoreduction, splenic radiation therapy (RT) has been done before the allogeneic transplant, but the role of splenic RT in this setting remains controversial. The purpose of this study is to evaluate the role of splenic RT before allogeneic BMT in patients with CML. Thirty-seven patients with chronic (n=33) or accelerated (n=4) phase CML underwent BMT from April 1990 to January 1998. All patients received splenic RT consisting of 500 cGy in five daily fractions (n=36) or 250 cGy in five daily fractions (n=1) completed within 10 days before BMT. The conditioning regimen included total-body irradiation and cyclophosphamide; etoposide was added to the regimen of patients in the accelerated phase. Continuous-infusion cyclosporine and pulse methotrexate were administered to all patients for prophylaxis of graft-vs.-host disease (GVHD). All patients achieved hematologic and cytogenetic remission. At a median follow-up of 37 months, the freedom from progression (FFP) and overall survival (OS) were 90 and 82%, respectively. None of the patients in accelerated phase have relapsed. Five patients have died of late transplant-related complications while in complete remission. Acute GVHD of grade > or = II was observed in 20% (14% grade II, 6% grade III). Fifty-one percent of patients developed limited chronic GVHD. The median posttransplant creatinine level was 1.2 mg/dL (range 0.6-4.2). Renal dysfunction, manifested as a persistent elevation in serum creatinine level (> 1.2 mg/dL), was observed in 40% of the patients. Only 8.5% had a creatinine level > 2.0 mg/dL, and no patient required dialysis as a result of renal dysfunction. Seven patients (18.9%) developed pulmonary complications, which included idiopathic interstitial pneumonitis (two), biopsy-proven interstitial fibrosis (four), and alveolar hemorrhage (one). The low relapse rate observed in this study may reflect the use of splenic RT as a part of the cytoreductive regimen before BMT. The fractionation schedule of 500 cGy in five daily fractions was well tolerated and did not appear to increase the toxicity of the preparative regimen. These favorable results indicate that splenic RT deserves further investigation and may be of benefit as a part of the conditioning regimen for patients receiving allogeneic BMT for CML.

Adult↗
PubMed1999

Early infection in bone marrow transplantation: quantitative study of clinical factors that affect risk.

Infections remain common life-threatening complications of bone marrow transplantation. To examine clinical factors that affect infection risk, we retrospectively studied patients who received bone marrow transplants (53 autologous and 51 allogeneic). Over a median of 27 hospital days, 44 patients developed documented infections. Both autologous transplantation and hematopoietic growth factor use were associated with less prolonged neutropenia and decreased occurrence of infection (P < or = .05). In a survival regression model, variables independently associated with infection risk were the log10 of the neutrophil count (hazard ratio [HR], 0.49; 95% confidence interval [CI], 0.32-0.75), ciprofloxacin prophylaxis (HR, 0.42; 95% CI, 0.19-0.95), empirical intravenous antibiotic use (HR, 0.09; 95% CI, 0.03-0.32), and an interaction between neutrophil count and intravenous antibiotic use (HR, 1.86; 95% CI, 1.06-3.29). In this model, infection risk increases steeply at low neutrophil counts for patients receiving no antibiotic therapy. Ciprofloxacin prophylaxis and particularly intravenous antibiotic therapy provide substantial protection at low neutrophil counts. These results can be used to model management strategies for transplant recipients.

Adult↗
PubMed1998

Discrepant cytogenetic and fluorescence in situ hybridization results in a 26-year-old male with early T-cell acute lymphocytic leukemia.

Analyzable G-banded metaphases were normal in bone marrow from a 26-year-old male having 80% blasts. Fluorescence in situ hybridization (FISH) using the centromeric probe, D7Z1, revealed 85% of interphase cells with one signal for chromosome 7. Chromosome painting revealed a chromosome 7 rearrangement in a few metaphases that were otherwise unanalyzable. A repeat bone marrow confirmed 3 of 20 metaphases, by G-banding, to have multiple rearrangements and aneuploidy, including a large derivative chromosome involving a complex rearrangement of chromosomes 5, 7, and 9; that is, der(5)t(5;9)(q31;q13)ins(5;7)(p15;q?31q?34), with loss of most of chromosome 7 (7 pter-->7q?31); one normal 7 was present. Immunophenotyping characterized the patient's condition as an early T-cell acute lymphocytic leukemia (ALL), with a population of cells suggesting biphenotypic leukemia. He attained a complete clinical remission with chemotherapy. Six months after the initial presentation he received an allogeneic bone marrow transplant. Three months later a CNS relapse was followed by a bone marrow relapse. At this time, eight months after transplant, repeat study of his bone marrow revealed the majority of metaphases had structural and numerical chromosome abnormalities similar to the small clone in the earlier study, including der(5)t(5;9)ins(5;7), but with two normal 7s. FISH showed two 7-centromere signals in interphase. The patient expired one month later.

Adult↗
PubMed1998

A multicenter study of platelet recovery and utilization in patients after myeloablative therapy and hematopoietic stem cell transplantation.

An observational study was conducted at 18 transplant centers in the United States and Canada to characterize the platelet recovery of patients receiving myeloablative therapy and stem cell transplantation and to determine the clinical variables influencing recovery, determine platelet utilization and cost, and incidence of hemorrhagic events. The study included 789 evaluable patients transplanted in 1995. Clinical, laboratory, and outcome data were obtained from the medical records. Variables associated with accelerated recovery in multivariate models included (1) higher CD34 count; (2) higher platelet count at the start of myeloablative therapy; (3) graft from an HLA-identical sibling donor; and (4) prior stem cell transplant. Variables associated with delayed recovery were (1) prior radiation therapy; (2) posttransplant fever; (3) hepatic veno-occlusive disease; and (4) use of posttransplant growth factors. Disease type also influenced recovery. Recipients of peripheral blood stem cells (PBSC) had faster recovery and fewer platelet transfusion days than recipients of bone marrow (BM). The estimated average 60-day platelet transfusion cost per patient was $4,000 for autologous PBSC and $11,000 for allogeneic BM transplants. It was found that 11% of all patients had a significant hemorrhagic event during the first 60 days posttransplant, contributing to death in 2% of patients. In conclusion, clinical variables influencing platelet recovery should be considered in the design and interpretation of clinical strategies to accelerate recovery. Enhancing platelet recovery is not likely to have a significant impact on 60-day mortality but could significantly decrease health care costs and potentially improve patient quality of life.

Antigens, CD34↗
PubMed1998

Vancomycin-resistant enterococcal infections in bone marrow transplant recipients.

Vancomycin-resistant enterococci (VRE) infections have been increasingly reported in immunosuppressed individuals over the past decade. Emergence of this pathogen in the bone marrow transplantation (BMT) setting, in the form of bacteremia or positive stool cultures, is of concern because of lack of effective antimicrobial therapy. We report episodes of vancomycin-resistant E. faecium bacteremia in two patients undergoing BMT including the first case of VRE meningitis observed in this setting. Since the outcome in these patients undergoing matched unrelated donor BMT was fatal, we believe that routine screening for VRE in high risk patients should be considered. Management of VRE carrier state in BMT candidates is unclear at present.

Adult↗
PubMed1997

A phase II multicenter trial of high-dose sequential chemotherapy and peripheral blood stem cell transplantation as initial therapy for patients with high-risk non-Hodgkin's lymphoma.

The purpose of this study was to evaluate the safety and feasibility of front-line high-dose sequential (HDS) chemotherapy with peripheral blood stem cell (PBSC) transplantation in patients with newly diagnosed high-risk non-Hodgkin's lymphoma (NHL). Thirty-two patients with high-risk NHL (defined by the age-adjusted international index) underwent HDS chemotherapy followed by PBSC transplantation and consolidative radiotherapy. Twenty-eight patients (88%) had intermediate/high grade NHL and four patients (12%) had small noncleaved or lymphoblastic lymphoma. Twenty-four patients were classified as high-intermediate-risk (two risk factors) and eight patients were classified as high-risk (three risk factors). The five phases of HDS (see Fig. 1) consisted of Phase I (adriamycin, vincristine, and prednisone); Phase II (cyclophosphamide, filgrastim [G-CSF], and PBSC harvest); Phase III (methotrexate, leucovorin, vincristine; Phase IV (etoposide, filgrastim [G-CSF]); and Phase V (mitoxantrone, melphalan, autologous peripheral blood stem cell infusion, and filgrastim [G-CSF]). Radiation therapy was given to sites of previous bulk disease, 2400 cGy, (D + 30-100)]. Toxicity, engraftment, hospital utilization, overall survival, and relapse-free survival were evaluated. The high-dose sequential chemotherapeutic regimen was well tolerated. Treatment-related mortality was 6.25% with two deaths occurring secondary to sepsis and one death was caused by progressive disease. The major toxicity in Phase I-IV was grade 3 nausea/vomiting. The major toxicity in Phase V was grade 3 or 4 nausea/vomiting and mucositis. The median follow-up is 18.8 months (range 4-44 months). The overall survival (OS) and relapse-free survival (RFS) at 18 months for all patients were 78% (95% CI 37-90%) and 67% (95% CI 46-88%), respectively. The OS at 18 months for all patients, excluding the four patients with either small noncleaved or lymphoblastic lymphoma, was 82% (95% CI 65-98%) vs. 30% (95% CI 0-86%) (p = 0.0059). One patient in this latter group remains alive at 6 months follow-up. The RFS for all patients, excluding the four patients with either small noncleaved or lymphoblastic lymphoma, was 78% (95% CI 58-97%) vs. 0% (95% CI 0-0%) (p = 0.0004). High-dose sequential chemotherapy with initial PBSC transplantation is well tolerated and appears effective in high-risk NHL. Superior results were noted in patients with intermediate grade versus those with small noncleaved or lymphoblastic NHL.

Adult↗
PubMed1996

A phase II trial of autologous bone marrow transplantation (ABMT) in acute leukemia with edelfosine purged bone marrow.

Alkyl-lysophospholipid compounds which are selectively cytotoxic to neoplastic cells and relatively sparing of normal marrow progenitor cells are appealing as purging agents to rid remission marrows of residual leukemic cells. A multi-institutional phase II study was conducted in 57 patients with acute leukemia (50 AML and 7 ALL) in which remission marrows were purged in vitro and reinfused after ablative chemotherapy. The median time for granulocyte recovery to 500/microliter was 33 days and for platelet recovery to 25000/microliter was 46 days. The overall DFS and survival was 37% and 46% respectively. Transplantation in first remission gave a better survival than transplant in a subsequent remission.

Adolescent↗
PubMed1996

High degree of occult tumor contamination in bone marrow and peripheral blood stem cells of patients undergoing autologous transplantation for non-Hodgkin's lymphoma.

Twenty patients with non-Hodgkin's lymphoma (NHL), primarily intermediate-and high-grade, were evaluated for evidence of bone marrow (BM) or peripheral blood stem cell (PBSC) lymphoma contamination using tumor-specific oligonucleotide-polymerase chain reaction (TSO-PCR). Patients were enrolled in a single-institution study comparing PBSC and bone marrow transplantation (BMT) for relapsed NHL. A molecular marker (CDR3 rearrangement, T cell beta receptor [TC beta R] rearrangement, or BCL-2/IgH rearrangement) was identified from analysis of the diagnostic tissue in 17 of 20 patients. Prior to undergoing BMT, 14 of 17 patients had PCR evidence of lymphoma involvement of either BM (11/17) or PBSCs (9/11). No decrease was found in the frequency of contamination of PBSCs compared with BM. In one patient, quantitative competitive PCR (C-PCR) identified a three- to tenfold greater quantity of contamination in the BM compared with PBSC. All evaluated patients (6/6) with contamination prior to BMT had persistence of marrow contamination following BMT. Our data demonstrate that TSO-PCR can generate a molecular marker for the majority of patients with intermediate- and high-grade NHL. In addition, we identified a high rate of occult lymphoma involvement in both BM and PBSC. As demonstrated by C-PCR, however, quantitative differences may exist in contamination of BM and PBSCs.

Base Sequence↗
PubMed1995

Granulocyte-macrophage colony stimulating factor (GM-CSF) priming in the treatment of elderly patients with acute myelogenous leukemia.

Standard intensive induction therapy is tolerated poorly by elderly patients with acute myeloblastic leukemia (AML). We treated 19 elderly patients with AML, including seven with a prior myelodysplastic syndrome (MDS) with a combination of low dose cytarabine, hydroxyurea, and GM-CSF. The percentage of blasts in S-phase was evaluated prior to and 24 hr after starting the GM-CSF infusion. Cell cycle analysis was performed by flow cytometry using propidium iodine staining with fluorescein isothiocyanate-conjugated monoclonal antibody to the myeloid antigen CD 33. Seven out of nineteen (37%) achieved a complete remission (CR) and six (31%) a partial remission (PR) for an overall response rate of 68% (13/19). There were three early deaths from infectious complications or organ failure. One patient died from disseminated fungal infection after attaining a PR. The medial overall survival was 9.5 months with a range of 1 to 23+ months. The projected median survival for the patients with de novo AML is greater than 23 months. The percentage of CD 33+ cells in S-phase increased from a mean of 11.6+/-2.7 (SEM) pre GM-CSF to 19.0+/-3.7 (SEM) post GM-CSF (P < 0.001). Patients with prior MDS demonstrated a greater increment (post-pre) in S-phase activity after GM-CSF administration (P = 0.02). There was a correlation between the increase in percent of CD 33+ cells in S-phase and the degree of cytoreduction as determined by the day 14 bone marrow biopsy (r = .78). The toxicity of the regimen was limited to the hematopoietic system. Sixteen out of nineteen patients (84%) and 12/13 (92%) of the responding patients had bone marrow aplasia on day 14. No patients experienced > grade 2 gastrointestinal toxicity. There was no neurologic or cardiac toxicity. These data suggest that the combination of hydroxyurea, GM-CSF, and cytarabine is an effective remission-induction regimen in elderly patients with AML.

Aged↗
PubMed1995

Degeneration of axons in the corticospinal tract secondary to spinal cord ischemia in rats.

Occlusion of the thoracic aorta and both subclavian arteries (XC) in the rat model produces spastic paraplegia. In order to characterize the lesion of white matter, 14 male Sprague-Dawley rats underwent XC for 10.5 to 12 min, were observed for 32 days and assessed with a lesion score. A sham group of eight underwent surgical manipulations without XC. The spinal cords were studied by optical microscopy and electron microscopy. An additional group of normal animals (n = 8) underwent spinal cord blood flow measurement with the autoradiographic technique. Optical microscopy showed normal histology in sham operated rats and rats with aortic cross-clamp and lesion score = 2-4 (n = 5), rare changes in the white matter of rats with lesion score = 8 (n = 2), and demyelination of the anterior and lateral tracts of the white matter and motor neuron loss in the gray matter of rats with lesion score = 13-15 (n = 7) and spastic paraplegia. In this last group, electron microscopy disclosed severe axonal degeneration of corticospinal tracts. In the same region spinal cord blood flow was higher than the remaining white matter. This study confirms that spastic paraplegia observed in the rat model after XC is due to degeneration of the pyramidal tracts, perhaps more susceptible to injury due to the high spinal cord blood flow.

Animals↗
PubMed1995

Large-volume leukapheresis for collection of mononuclear cells for hematopoietic rescue in Hodgkin's disease.

BACKGROUND: Peripheral blood mononuclear cells (MNCs) collected by leukapheresis contain hematopoietic stem and progenitor cells that provide autologous hematopoietic rescue after high-dose chemotherapy, an approach that offers a significant benefit to patients with recurrent Hodgkin's disease. However, patients with low MNC counts may require 10 or more standard leukapheresis procedures for the collection of sufficient cells for hematopoietic rescue. STUDY DESIGN AND METHODS: The effectiveness of steady-state large-volume leukapheresis (LVL; 15-35 L blood processed) was evaluated as a method for collecting MNCs for hematopoietic rescue in seven patients with recurrent Hodgkin's disease. LVL was performed on 2 consecutive days per week to collect 7 x 10(8) MNCs per kg. The circulating MNC counts on the first day of LVL and the total numbers of LVL, of MNCs collected, and of liters of blood processed were determined per patient. After high-dose chemotherapy and MNC transfusion, days to granulocyte and platelet engraftment were recorded. RESULTS: On the first day of LVL, patients had median circulating MNCs of 1536 (range, 504-3950) x 10(6) per L. The median number of LVL procedures per patient was four (range, 1.25-6), and the median L per kg of blood processed was 1.57 (range, 0.38-4.03). Simple regression analysis plotting L per kg against initial MNCs gave a curve with the equation y = e(1.42-(6.31 x 10E-4)x) (correlation coefficient = -0.97, R2 = 0.95, exponential fit). Without posttransfusion growth-factor support, median days to granulocyte engraftment were 19 (range, 12-26) and those to platelet transfusion independence were 34.5 (range, 10-57). CONCLUSION: LVL provides a useful method of collecting MNCs for hematopoietic rescue in patients with Hodgkin's disease. The patient's baseline MNC count provides a useful estimate of the volume required for LVL.

Adult↗
PubMed1995

Calcium- and protein kinase C-dependent basal tone in the aorta of hypertensive rats.

We examined the regulatory influence of nitric oxide on development of calcium- and protein kinase C-dependent basal tone in rings of thoracic aortas from rats with aortic coarctation-induced hypertension and from normotensive controls. Aortic rings from hypertensive rats but not those from normotensive rats, bathed in Krebs' bicarbonate buffer and subjected to 2 g of passive stretch, were relaxed by removal of calcium from the buffer and by the protein kinase C inhibitors staurosporine and calphostin C. Protein kinase C activity was much greater in homogenates of aortae from hypertensive rats than in those from normotensive controls (2124 +/- 785 versus 608 +/- 73 pmol.min-1.mg protein-1, respectively). Relaxant responses to removal of calcium and to staurosporine were greater in aortic rings rubbed to remove the vascular endothelium than in endothelium-intact rings (-1.07 +/- 0.12 versus -0.70 +/- 0.10 g tension/mg tissue, respectively, for calcium removal and -1.10 +/- 0.12 versus -0.65 +/- 0.08 g tension/mg tissue, respectively, for staurosporine). Treatment with an inhibitor of nitric oxide synthesis increased calcium-dependent tone in both intact and endothelium-denuded aortic rings from hypertensive rats. Conversely, the administration of sodium nitroprusside or L-arginine reversed tone in both intact and denuded aortic rings from hypertensive rats, but acetylcholine reversed tone only in intact rings. The relaxant effects of these agents were paralleled by increases in cyclic guanosine monophosphate in aortic tissue. We conclude that aortic rings from rats with aortic coarctation-induced hypertension display calcium-dependent, protein kinase C-mediated tone in the absence of exogenous vasoconstrictors.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1995

Improved survival for patients with acute myelogenous leukemia.

PURPOSE: Despite improvement in chemotherapy and supportive care over the past two decades, overall survival for patients with acute myelogenous leukemia (AML) remains poor; only 25% to 30% of individuals with this disorder will be cured. In 1987, we initiated a prospective multiinstitution study designed to improve long-term survival in adults with AML. METHODS: We modified the usual 7-day treatment scheme of daunorubicin and cytarabine with high-dose cytarabine (HiDAC) on days 8 through 10 (3 + 7 + 3). Allogeneic or autologous bone marrow transplantation (BMT) was offered to all patients who entered complete remission (CR) to decrease the rate of leukemic relapse. Data were analyzed by intention to treat. RESULTS: CRs were achieved in 84 of 94 patients (89%; 95% confidence interval [CI], 83 to 95). Because of the high remission rate, factors previously thought to predict outcome, such as cytogenetics, WBC count, French-American-British (FAB) classification, sex, and age, were not useful prognostic variables. The overall survival rate for the entire cohort of patients from data of diagnosis is 55% at 5 years. Sixty percent of all patients who achieved a CR underwent marrow grafting. There was no significant difference in event-free survival (EFS) at 5 years comparing patients assigned to receive allogeneic BMT with patients assigned to receive autologous BMT (56% v 45%, P = .54). CONCLUSION: The long-term disease-free survival observed in this study is excellent compared with historical data. This improvement in survival is probably due to the high rate of remission induction, as well as to the effective nature of the consolidation therapy.

Adolescent↗
PubMed1995

Enhanced responses to L-arginine in aortic rings from rats with angiotensin-dependent hypertension.

We contrasted, in normotensive and hypertensive rats, the effect of L-arginine on isometric tension of phenylephrine-contracted rings of aorta bathed in Krebs' bicarbonate buffer on cyclic guanosine monophosphate content of aortic rings and on blood pressure. L-Arginine had no effect on isometric tension or cyclic guanosine monophosphate content of aortic rings from normotensive controls. Conversely, L-arginine (10(-5)-10(-3) mol/l) induced concentration-dependent relaxation of unrubbed and rubbed rings of thoracic and abdominal aorta and, as well, L-arginine (10(-3) mol/l) increased cyclic guanosine monophosphate in unrubbed and rubbed rings of thoracic aorta taken from hypertensive rats 7 to 14 days after aortic coarctation. Similar relaxations to L-arginine were seen in rings of thoracic and abdominal aorta from rats made hypertensive by infusion of angiotensin II for 7 to 8 days but not in rings of thoracic aorta from rats with aortic coarctation-induced hypertension of 28 to 42 days. Relaxant responses to L-arginine in rings of thoracic aorta from hypertensive rats 7 to 14 days after aortic coarctation were unaffected by pretreatment of rings with dexamethasone (10(-7) mol/l) or L-arginine (10(-4) mol/l) but were blunted by NG-nitro-L-arginine methylester (3 x 10(-4) mol/l) or methylene blue (10(-5) mol/l). Our results suggest that the vasorelaxant effects of L-arginine in aortic rings from hypertensive rats 7 to 14 days after aortic coarctation and 7 to 8 days after commencing angiotensin II infusion are mediated by nitric oxide.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin II↗