Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 237
Filter
Add more filters

Country/Region as subject
Publication year range
1.
Phys Rev Lett ; 133(1): 012501, 2024 Jul 05.
Article in English | MEDLINE | ID: mdl-39042802

ABSTRACT

To search for low-energy resonant structures in isospin T=3/2 three-body systems, we have performed the experiments ^{3}H(t,^{3}He)3n and ^{3}He(^{3}He,t)3p at intermediate energies. For the 3n experiment, we have newly developed a thick Ti-^{3}H target that has the largest tritium thickness among targets of this type ever made. The 3n experiment for the first time covered the momentum-transfer region as low as 15 MeV/c, which provides ideal conditions for producing fragile systems. However, in the excitation-energy spectra we obtained, we did not observe any distinct peak structures. This is in sharp contrast to tetraneutron spectra. The distributions of the 3n and 3p spectra are found to be similar, except for the displacement in energy due to Coulomb repulsion. Comparisons with theoretical calculations suggest that three-body correlations exist in the 3n and 3p systems, although not enough to produce a resonant peak.

2.
Phys Rev Lett ; 131(20): 202501, 2023 Nov 17.
Article in English | MEDLINE | ID: mdl-38039485

ABSTRACT

The changes in mean-squared charge radii of neutron-deficient gold nuclei have been determined using the in-source, resonance-ionization laser spectroscopy technique, at the ISOLDE facility (CERN). From these new data, nuclear deformations are inferred, revealing a competition between deformed and spherical configurations. The isotopes ^{180,181,182}Au are observed to possess well-deformed ground states and, when moving to lighter masses, a sudden transition to near-spherical shapes is seen in the extremely neutron-deficient nuclides, ^{176,177,179}Au. A case of shape coexistence and shape staggering is identified in ^{178}Au which has a ground and isomeric state with different deformations. These new data reveal a pattern in ground-state deformation unique to the gold isotopes, whereby, when moving from the heavy to light masses, a plateau of well-deformed isotopes exists around the neutron midshell, flanked by near-spherical shapes in the heavier and lighter isotopes-a trend hitherto unseen elsewhere in the nuclear chart. The experimental charge radii are compared to those from Hartree-Fock-Bogoliubov calculations using the D1M Gogny interaction and configuration mixing between states of different deformation. The calculations are constrained by the known spins, parities, and magnetic moments of the ground states in gold nuclei and show a good agreement with the experimental results.

3.
Phys Rev Lett ; 124(2): 022501, 2020 Jan 17.
Article in English | MEDLINE | ID: mdl-32004026

ABSTRACT

Spectroscopic factors of neutron-hole and proton-hole states in ^{131}Sn and ^{131}In, respectively, were measured using one-nucleon removal reactions from doubly magic ^{132}Sn at relativistic energies. For ^{131}In, a 2910(50)-keV γ ray was observed for the first time and tentatively assigned to a decay from a 5/2^{-} state at 3275(50) keV to the known 1/2^{-} level at 365 keV. The spectroscopic factors determined for this new excited state and three other single-hole states provide first evidence for a strong fragmentation of single-hole strength in ^{131}Sn and ^{131}In. The experimental results are compared to theoretical calculations based on the relativistic particle-vibration coupling model and to experimental information for single-hole states in the stable doubly magic nucleus ^{208}Pb.

5.
Am J Transplant ; 17(1): 115-128, 2017 01.
Article in English | MEDLINE | ID: mdl-27343838

ABSTRACT

The mechanism of long-term B cell immunity against donor blood group antigens in recipients who undergo ABO-incompatible (ABOi) living-donor kidney transplantation (LKTx) is unknown. To address this question, we evaluated serial anti-A and anti-B antibody titers in 50 adult recipients. Donor-specific antibody titers remained low (≤1:4) in 42 recipients (84%). However, antibodies against nondonor blood group antigens were continuously produced in recipients with blood type O. We stimulated recipients' peripheral blood mononuclear cells in vitro to investigate whether B cells produced antibodies against donor blood group antigens in the absence of graft adsorption in vivo. Antibodies in cell culture supernatant were measured using specific enzyme-linked immunosorbent assays (ELISAs). Thirty-five healthy volunteers and 57 recipients who underwent ABO-compatible LKTx served as controls. Antibody production in vitro against donor blood group antigens by cells from ABOi LKTx patients was lower than in the control groups. Immunoglobulin deposits were undetectable in biopsies of grafts of eight recipients with low antibody titers (≤1:4) after ABOi LKTx. One patient with blood type A1 who received a second ABOi LKTx from a type B donor did not produce B-specific antibodies. These findings suggest diminished donor-specific antibody production function in the setting of adult ABOi LKTx.


Subject(s)
ABO Blood-Group System/immunology , Blood Group Incompatibility/immunology , Isoantibodies/blood , Kidney Failure, Chronic/surgery , Kidney Transplantation , Leukocytes, Mononuclear/immunology , Adolescent , Adult , Aged , Antibody Formation , Child , Down-Regulation , Female , Follow-Up Studies , Glomerular Filtration Rate , Humans , Isoantibodies/immunology , Kidney Function Tests , Male , Middle Aged , Prognosis , Risk Factors , Tissue Donors , Young Adult
6.
J Stroke Cerebrovasc Dis ; 26(5): 1144-1153, 2017 May.
Article in English | MEDLINE | ID: mdl-28256416

ABSTRACT

BACKGROUND: Vertigo or dizziness is a common occurrence, but it remains a challenging symptom when encountered in the emergency department (ED). A diagnostic score for stroke with high accuracy is therefore required. METHODS: A single-center observational study (498 patients) was conducted. The predictor variables were derived from a multivariate logistic regression analysis with Akaike information criterion. The outcome was the occurrence of stroke. We evaluated the utility of a new diagnostic score (TriAGe+) and compared it with the ABCD2 score. RESULTS: The cohorts included 498 patients (147 with stroke [29.4%]). Eight variables were included: triggers, atrial fibrillation, male gender, blood pressure ≥140/90 mm Hg, brainstem or cerebellar dysfunction, focal weakness or speech impairment, dizziness, and no history of vertigo or dizziness or labyrinth or vestibular disease. We derived the TriAGe+ score from these variables. In the cohort, the prevalence of stroke increased significantly using the diagnostic score: 5.9% for a score of 0-4; 9.1% for 5-7; 24.7% for 8-9; and 57.3% for 10-17. At a cutoff value of 10 points, the sensitivity of the score was 77.5%, the specificity was 72.1%, and the positive likelihood ratio was 3.2. When the cutoff was defined as 5 points, the score obtained a high sensitivity (96.6%) with a good negative likelihood ratio (.15). The new score outperformed the ABCD2 score for the occurrence of stroke (C statistic, .818 versus .726; P < .001). CONCLUSIONS: The TriAGe+ score can identify the occurrence of stroke in patients with vertigo or dizziness presenting to the ED.


Subject(s)
Decision Support Techniques , Dizziness/epidemiology , Emergency Service, Hospital , Stroke/diagnosis , Stroke/epidemiology , Triage/methods , Vertigo/epidemiology , Aged , Aged, 80 and over , Area Under Curve , Female , Humans , Japan/epidemiology , Male , Middle Aged , Observer Variation , Predictive Value of Tests , Prevalence , Prognosis , ROC Curve , Reproducibility of Results , Risk Assessment , Risk Factors
7.
Phys Rev Lett ; 115(17): 172503, 2015 Oct 23.
Article in English | MEDLINE | ID: mdl-26551108

ABSTRACT

Absolute cross sections for isotopically identified products formed in multinucleon transfer in the (136)Xe+(198)Pt system at ∼8 MeV/nucleon are reported. The isotopic distributions obtained using a large acceptance spectrometer demonstrated the production of the "hard-to-reach" neutron-rich isotopes for Z<78 around the N=126 shell closure far from stability. The main contribution to the formation of these exotic nuclei is shown to arise in collisions with a small kinetic energy dissipation. The present experimental finding corroborates for the first time recent predictions that multinucleon transfer reactions would be the optimum method to populate and characterize neutron-rich isotopes around N=126 which are crucial for understanding both astrophysically relevant processes and the evolution of "magic" numbers far from stability.

8.
Sci Rep ; 14(1): 2573, 2024 Feb 09.
Article in English | MEDLINE | ID: mdl-38336981

ABSTRACT

To detect and track structural changes in atomic nuclei, the systematic study of nuclear levels with firm spin-parity assignments is important. While linear polarization measurements have been applied to determine the electromagnetic character of gamma-ray transitions, the applicable range is strongly limited due to the low efficiency of the detection system. The multi-layer Cadmium-Telluride (CdTe) Compton camera can be a state-of-the-art gamma-ray polarimeter for nuclear spectroscopy with the high position sensitivity and the detection efficiency. We demonstrated the capability to operate this detector as a reliable gamma-ray polarimeter by using polarized 847-keV gamma rays produced by the [Formula: see text]([Formula: see text]) reaction. By combining the experimental data and simulated calculations, the modulation curve for the gamma ray was successfully obtained. A remarkably high polarization sensitivity was achieved, compatible with a reasonable detection efficiency. Based on the obtained results, a possible future gamma-ray polarimetery is discussed.

9.
Br J Cancer ; 107(6): 988-93, 2012 Sep 04.
Article in English | MEDLINE | ID: mdl-22878374

ABSTRACT

BACKGROUND: Inflammation-based prognostic scores including the Glasgow Prognostic Score (GPS), neutrophil to lymphocyte ratio (NLR), and Prognostic Nutritional Index (PNI) are associated with survival in patients with hepatocellular carcinoma (HCC). The aim of this study was to investigate the prognostic value of these inflammation-based prognostic scores in patients with HCC. METHODS: In total, 150 patients with newly diagnosed HCC were prospectively evaluated. Patients were divided according to the GPS, modified GPS, NLR, platelet to lymphocyte ratio (PLR), Prognostic Index (PI), and PNI. The area under the receiver operating characteristics curve (AUC) was calculated to compare the predictive ability of each of the scoring systems. A univariate and multivariate analysis were performed to identify the clinicopathological variables associated with overall survival. RESULTS: The GPS consistently had a higher AUC value at 6 months (0.768), 12 months (0.787), and 24 months (0.758) in comparison with other inflammation-based prognostic scores. A multivariate analysis showed that the GPS was independently associated with overall survival. CONCLUSION: This study demonstrates that the GPS, an inflammation-based prognostic score, is an independent marker of poor prognosis in patients with HCC and is superior to the other inflammation-based prognostic scores in terms of prognostic ability.


Subject(s)
Biomarkers, Tumor/blood , Carcinoma, Hepatocellular/pathology , Inflammation Mediators/blood , Liver Neoplasms/pathology , Adult , Aged , Aged, 80 and over , Analysis of Variance , Area Under Curve , Carcinoma, Hepatocellular/blood , Female , Follow-Up Studies , Humans , Liver Neoplasms/blood , Male , Middle Aged , Predictive Value of Tests , Prognosis , Prospective Studies , ROC Curve , Survival Analysis
10.
Cephalalgia ; 30(4): 496-9, 2010 Apr.
Article in English | MEDLINE | ID: mdl-19515123

ABSTRACT

Patients with severe primary headache may benefit from consultation with headache specialists, but doctor attendance rates in Japan are very low. More headache patients might consult headache specialists if these specialists were more widely recognized by the public. To determine what information prompted patients to seek consultation with a headache specialist, we questioned 256 primary headache patients about the source of the helpful information concerning consultation with headache specialists. From 191 patients, a total of 235 responses to the questionnaire were obtained. The most common response was 'websites' (33.2%), followed by 'professionals' (23.8%), 'acquaintances' (20.9%), 'print media' (6.8%) and 'TV/radio' (3.4%). Patients who indicated websites showed the most severe pain and highest impact of headache, and accounted for 52.4% of those with cluster headaches. Development of websites concerning headache specialists would seem likely to increase doctor attendance rates for patients with primary headache.


Subject(s)
Cluster Headache/therapy , Headache Disorders, Primary/therapy , Internet/statistics & numerical data , Patient Acceptance of Health Care/statistics & numerical data , Patient Education as Topic/statistics & numerical data , Referral and Consultation/statistics & numerical data , Adult , Asian People/statistics & numerical data , Cluster Headache/ethnology , Female , Headache Disorders, Primary/ethnology , Humans , Information Dissemination , Japan/epidemiology , Male , Mass Media/statistics & numerical data , Middle Aged , Neurology/statistics & numerical data , Patient Satisfaction , Surveys and Questionnaires , Young Adult
11.
Clin Nephrol ; 74(1): 74-80, 2010 Jul.
Article in English | MEDLINE | ID: mdl-20557871

ABSTRACT

We report a 38-year-old woman diagnosed with tubulointerstitial nephritis (TIN) on renal biopsy, followed by being diagnosed with primary biliary cirrhosis (PBC) and Sjögren's syndrome (SS). Immunohistochemically, the cellular infiltrates in TIN were mainly composed of small lymphocytes and IgM-positive plasmacytoid large lymphocytes. IgM-positive plasmacytoid large lymphocytes were not identical with, but colocalized with CD3- or CD20-positive lymphocytes. TIN in patients with PBC is very rare and little is known about immunohistochemical characteristics of infiltrating cells in this setting. To our knowledge, this is the first report demonstrating predominant infiltrating of IgM-positive plasmacytoid large lymphocytes in TIN due to PBC and SS.


Subject(s)
Liver Cirrhosis, Biliary/pathology , Nephritis, Interstitial/pathology , Sjogren's Syndrome/pathology , T-Lymphocyte Subsets/pathology , Adult , Biopsy , Female , Humans , Immunoglobulin M/immunology , Immunohistochemistry
12.
Clin Nephrol ; 71(2): 173-8, 2009 Feb.
Article in English | MEDLINE | ID: mdl-19203510

ABSTRACT

We describe an elderly man with membranous nephropathy and lymphoplasmacytic infiltration into the renal interstitium who presented with a high serum IgG4 concentration and no organ involvement in the pancreatobiliary system. Although the patient had hypocomplementemia and was positive for antinuclear antibodies, he was negative for antibodies against Sm, SS-A, SS-B and RNP, and his anti-DNA antibody titer was not elevated. Immunohistochemistry demonstrated that the infiltrated plasma cells in the renal interstitium and glomerular capillary walls were strongly positive for IgG4. Electron microscopy showed electron-dense deposits on the glomerular basement membranes and tubular basement membranes. The present case suggests that membranous nephropathy, like tubulo-interstitial nephritis, is one of the renal features of IgG4-related systemic disease.


Subject(s)
Glomerulonephritis, Membranous/blood , Immunoglobulin G/blood , Aged, 80 and over , Autoimmune Diseases/blood , Glomerulonephritis, Membranous/pathology , Humans , Immunohistochemistry , Male , Pancreatitis/blood , Staining and Labeling
13.
Rev Sci Instrum ; 79(2 Pt 2): 02A906, 2008 Feb.
Article in English | MEDLINE | ID: mdl-18315161

ABSTRACT

The KEKCB is an electron cyclotron resonance (ECR) ion source for converting singly charged ions to multicharged ones at Tokai Radioactive Ion Accelerator Complex. By using the KEKCB, singly charged gaseous and nongaseous ions were converted to multicharged ones of A/q approximately 7 with efficiencies of 7% and 2%, respectively. The conversion efficiency was found to be independent of the lifetime of the radioactive nuclei having lifetimes of the order of one second. Three collimators located at the entrance and the exit of the KEKCB defined the beam axis and facilitated beam injection. Grinding and washing the surfaces of aluminum electrode and plasma chamber dramatically reduced impurities originating from the ECR plasma of the KEKCB.

14.
Leuk Lymphoma ; 47(1): 89-95, 2006 Jan.
Article in English | MEDLINE | ID: mdl-16465716

ABSTRACT

Various angiogenic factors, such as vascular endothelial growth factor (VEGF) and an associated molecule, placenta growth factor (PlGF), are thought to be important for normal and malignant hematopoiesis. This study examined mRNA expression of VEGF, PlGF and receptors for these molecules in AML cells and identified the disease-specific patterns of expression. AML M3 having t(15;17) abnormality showed highest expression of VEGF and VEGF receptor type 1 (VEGFR1), suggesting the autocrine pathway of VEGF-VEGFR1. Then, t(8;21) AML demonstrated augmented expression of VEGF and VEGF receptor type 2 (VEGFR2), suggesting VEGF-VEGFR2 autocrine pathway. Then, addition of VEGFR2 kinase inhibitor in Kasumi-1, a t(8;21) AML cell line, resulted in marked inhibition of cell growth, although growth inhibitory effect of R2 kinase inhibitor to HL-60 was marginal. In addition, cell cycle analysis study showed S-phase cell population reduction by R2 kinase inhibitor in Kasumi-1, but not in HL-60. This observation is thought to be the rationale for novel molecular target therapy directed to angiogenic molecules.


Subject(s)
Autocrine Communication/genetics , Leukemia, Myeloid, Acute/genetics , Translocation, Genetic/genetics , Vascular Endothelial Growth Factor A/genetics , Vascular Endothelial Growth Factor Receptor-1/genetics , Vascular Endothelial Growth Factor Receptor-2/genetics , Adult , Aged , Cell Cycle/drug effects , Cell Cycle/physiology , Cell Line, Tumor , Cell Proliferation/drug effects , Chromosome Aberrations , Chromosomes, Human, Pair 15/genetics , Chromosomes, Human, Pair 17/genetics , Chromosomes, Human, Pair 21/genetics , Chromosomes, Human, Pair 8/genetics , Disease , Enzyme Inhibitors/pharmacology , Gene Expression Regulation, Leukemic/genetics , HL-60 Cells , Humans , Leukemia, Myeloid, Acute/metabolism , Middle Aged , Placenta Growth Factor , Pregnancy Proteins/biosynthesis , Pregnancy Proteins/genetics , RNA, Messenger/biosynthesis , RNA, Messenger/genetics , Reverse Transcriptase Polymerase Chain Reaction , Tumor Cells, Cultured , Vascular Endothelial Growth Factor A/biosynthesis , Vascular Endothelial Growth Factor Receptor-1/biosynthesis , Vascular Endothelial Growth Factor Receptor-2/antagonists & inhibitors , Vascular Endothelial Growth Factor Receptor-2/biosynthesis
15.
Food Chem Toxicol ; 44(4): 560-6, 2006 Apr.
Article in English | MEDLINE | ID: mdl-16256256

ABSTRACT

This study was designed to evaluate and characterize any subchronic toxicity of a new type of gum arabic (SUPER GUM [Acacia(sen)SUPER GUM]), a naturally processed polysaccharide exudate from gum acacia trees (Acacia senegal), when administered to both sexes of F344 rats at dietary levels of 0 (control), 1.25%, 2.5%, and 5.0% (10 rats/sex/group). During the study, the treatment had no effects on clinical signs, survival, body weights, and food and water consumption, or on findings of urinalysis, ophthalmology, hematology, or blood biochemistry. Gross pathology and histopathology exhibited no differences of toxicological significance between control and treated rats. Increased relative cecum (filled) weights, evident in both sexes of 5.0% group and females of 1.25% and 2.5% groups, were considered to be a physiological adaptation. Thus, the results indicated the toxic level of SUPER GUM to be more than 5.0%, and the no observed adverse effect level (NOAEL) was concluded to be 5.0% (3,117 mg/kg body weights/day for males, and 3,296 mg/kg body weights/day for males) from the present study.


Subject(s)
Fabaceae , Food Additives/toxicity , Gum Arabic/toxicity , Phytotherapy , Administration, Oral , Animals , Female , Food Additives/administration & dosage , Gum Arabic/administration & dosage , Male , Rats , Rats, Inbred F344
16.
Indian J Nephrol ; 26(2): 107-12, 2016.
Article in English | MEDLINE | ID: mdl-27051134

ABSTRACT

The long-term prognosis of patients with IgA nephropathy (IgAN) who present with preserved renal function and minimal proteinuria is not well described. We investigated the long-term outcomes of IgAN patients with an apparently benign presentation and evaluated prognostic factors for renal survival and clinical remission. We studied Japanese patients with biopsy-proven IgAN who had an estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m(2) and proteinuria <0.5 g/day at the time of renal biopsy. The renal biopsies were reviewed using the Oxford classification. Twenty patients met the inclusion criteria. At diagnosis, the median eGFR (interquartile range) was 76.8 (65.2-91.1) mL/min/1.73 m(2), and the median proteinuria level was 0.31 (0.16-0.39) g/day. Only one patient had an increase in serum creatinine of over 50% and no patient progressed to end-stage renal disease. The 15-year renal survival rate was 93.8%. Clinical remission was observed in 9 (45%) patients. Baseline proteinuria was the only factor significantly associated with the absence of clinical remission. The long-term prognosis of Japanese patients with IgAN who presents with minor urinary abnormalities and preserved renal function is excellent.

17.
Indian J Nephrol ; 26(6): 423-426, 2016.
Article in English | MEDLINE | ID: mdl-27942174

ABSTRACT

Long-term follow-up of kidney donors is needed not only for the individual donor's benefit but also to establish analyzable databases to improve the selection criteria for future donors. We collected data including the date of transplantation, the date of the last follow-up, donor's age, sex, their relationship to the recipient, renal function, proteinuria, and the prevalence of hypertension. Of 124 donors, 52 donors were not being followed up. The mean duration of follow-up was 4.3 ± 3.6 years. Follow-up rates were 83.9%, 74.6%, and 59.2% at 1 year, 2 years, and 5 years postdonation, respectively. Of those not being followed up, 75% dropped out. Follow-up rates did not differ between parent and spouse donors 5 years (57.1% vs. 71.4%; P = 0.4) postdonation. Similarly, follow-up rates at 5 years did not differ between donors aged 60 years or older and those younger than 60 (57.5% vs. 61.3%; P = 0.6). Of 72 donors being followed up, 75.0% had estimated glomerular filtration rate of <60 mL/min/1.73 m2, 8.3% had proteinuria, and 41.7% had hypertension requiring medication. There is a limitation to the endeavor of each transplant center to follow-up all their donors. Long-term donor follow-up in Japan requires a national registration system and mandates transplant center participation.

18.
Transplant Proc ; 48(6): 2046-9, 2016.
Article in English | MEDLINE | ID: mdl-27569942

ABSTRACT

BACKGROUND: Hepatitis B virus (HBV) infection is a risk factor of mortality in kidney transplant recipients. However, information on the risk of HBV reactivation in kidney recipients with prior resolved HBV infection is limited. This study aimed to evaluate the safety of simply monitoring viral and liver markers in living donor kidney transplantation (LDKT) recipients with prior resolved HBV infection. METHODS: We retrospectively examined the clinical records of LDKT recipients. Changes in the levels of alanine aminotransferase, aspartate aminotransferase, hepatitis B surface antigen (HBs Ag), surface antibody, core antibody, and HBV-DNA after transplantation were evaluated, and the occurrence of de novo HBV-related hepatitis and allograft function were monitored. RESULTS: Of 61 consecutive LDKT patients, seven had prior resolved HBV infection. Four patients underwent ABO-compatible LDKT, whereas two underwent ABO-incompatible LDKT. The median age was 64 years (range, 61-69 years), and two patients were women. The causes of end-stage kidney disease were diabetic nephropathy, hypertensive nephrosclerosis, and chronic glomerulonephritis. Five patients were referred to hepatologists. The history of HBV vaccination was not confirmed in all patients. Prophylaxis with entecavir was administered to two patients with ABO-incompatible LDKT before transplantation. All patients tested negative for HBs Ag and HBV-DNA throughout observation, and none developed de novo HBV-related hepatitis or graft loss. CONCLUSIONS: Patients with HBV infection without HBV DNA positivity are eligible for kidney transplants without antiviral therapy, even those on rituximab therapy. Monitoring viral and liver markers combined with hepatologist consultations may ensure safe follow-up in LDKT recipients with prior resolved HBV infection.


Subject(s)
Antiviral Agents/therapeutic use , Hepatitis B/prevention & control , Kidney Failure, Chronic/surgery , Kidney Failure, Chronic/virology , Kidney Transplantation , Adult , Aged , Alanine Transaminase/blood , Biomarkers/blood , Female , Guanine/analogs & derivatives , Guanine/therapeutic use , Hepatitis B Antibodies/blood , Hepatitis B Surface Antigens/blood , Humans , Immunoglobulins/therapeutic use , Kidney Failure, Chronic/metabolism , Male , Middle Aged , Retrospective Studies , Risk Factors
19.
Biochim Biophys Acta ; 626(2): 501-6, 1980 Dec 16.
Article in English | MEDLINE | ID: mdl-7213666

ABSTRACT

The electrochemical behavior of iron storage protein, ferritin (molecular weight 700 000) was studied by pulse polarography, cyclic voltammetry and 'potentiometry' monitored by colorimetry. Comparison between in vivo and voltammetric redox reactions of the ferritin Fe(III) core and thermodynamic E'0 values for native ferritin are described.


Subject(s)
Ferritins , Electrochemistry , Ferritins/metabolism , Iron/metabolism , Oxidation-Reduction , Thermodynamics
20.
J Am Coll Cardiol ; 23(1): 194-200, 1994 Jan.
Article in English | MEDLINE | ID: mdl-8277081

ABSTRACT

OBJECTIVES: The purpose of this study was to determine the effects of naloxone on systemic hemodynamics and reflex function in dogs with congestive heart failure induced by rapid pacing. BACKGROUND: We have shown previously that naloxone, an opiate receptor antagonist, improves cardiac output, aortic blood pressure, systolic performance and the baroreflex function in conscious dogs with chronic right-sided congestive heart failure. However, whether endogenous opioids also play a role n mediating the reduction of myocardial and baroreflex function in animals with left heart failure remains controversial. METHODS: We administered naloxone (1 mg/kg body weight) and normal saline solution to 15 dogs with pacing-induced congestive heart failure (225 beats/min for 8 weeks) and 11 control dogs. In addition to systemic hemodynamic measurements, the slope of pressure-area relation obtained from echocardiography with intravenous bolus injection of phenylephrine was taken as a load-independent index of myocardial contractility. Baroreflex function was estimated by the slope of the regression line relating systolic aortic pressure and RR interval. RESULTS: Plasma beta-endorphin levels were elevated in dogs with congestive heart failure. Naloxone administration increased heart rate, mean aortic pressure, first derivative of left ventricular pressure, cardiac output and myocardial contractility in pacing-induced congestive heart failure. These changes correlated significantly with basal plasma beta-endorphin levels and were accompanied by increases in plasma beta-endorphin and catecholamines after naloxone administration. However, unlike the hemodynamic and cardiac effects of naloxone, baroreflex function did not change after naloxone in dogs with congestive heart failure. CONCLUSIONS: The increase in basal plasma beta-endorphin suggests that the endogenous opiate system is activated in left-sided congestive heart failure. Because naloxone improves the systemic hemodynamics and myocardial contractile function under this condition, the endogenous opioids appear to play an important role in mediating the myocardial depression that occurs in heart failure. However, the endogenous opiate system has no apparent effect on the regulation of baroreflex control in heart failure induced by rapid pacing.


Subject(s)
Baroreflex/drug effects , Heart Failure/physiopathology , Hemodynamics/drug effects , Naloxone/pharmacology , Ventricular Function, Left/drug effects , Animals , Disease Models, Animal , Dogs , Epinephrine/blood , Heart Failure/drug therapy , Myocardial Contraction/drug effects , Narcotic Antagonists , Norepinephrine/blood , beta-Endorphin/blood
SELECTION OF CITATIONS
SEARCH DETAIL