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Biomedical subjects

C V Oddis

Publications and source records attributed to C V Oddis.

At least 37 records · Page 2Linked to original sources
PubMed1996

Protein kinase A activation is required for IL-1-induced nitric oxide production by cardiac myocytes.

We have previously reported that interleukin-1 beta (IL-1) alone induced the transcription of inducible nitric oxide synthase (iNOS) mRNA and nitric oxide (NO) production by isolated neonatal rat cardiac myocytes (CM). The present studies were undertaken to explore the signal transduction pathways involved in IL-1-induced NO production by CM. The addition of IL-1 to CM resulted in a peak rise in both adenosine 3',5'-cyclic monophosphate (cAMP) and protein kinase A (PKA) activities by 10 min followed by rapid declines and return to basal levels within 60 min. The PKA inhibitor KT-5720 completely blocked NO-2 production by IL-1-stimulated CM (P < 0.01; n = 12). The protein kinase C (PKC) inhibitor, calphostin C, had no effect on NO2- production by IL-1 stimulated CM [P = not significant (NS); n = 12]. The addition of PKA+cAMP to cytosols derived from IL-1-treated CM did not directly enhance iNOS enzyme activity (P = NS; n = 3). CM treated with IL-1 alone stained positively for iNOS protein by immunohistochemistry. iNOS staining was absent in CM treated with IL-1+KT-5720. KT-5720 resulted in an earlier disappearance of iNOS mRNA from IL-1-treated CM, as detected by semiquantitative reverse transcriptase-polymerase chain reaction. We report for the first time that PKA (but not PKC) activation is required for IL-1-induced NO production by CM.

Animals↗
PubMed1996

Glucose and pyruvate regulate cytokine-induced nitric oxide production by cardiac myocytes.

Metabolic requirements for the production of nitric oxide (NO) by cytokine-stimulated neonatal rat cardiac myocytes (CM) were studied. CM were cultured for 48 h in media containing interleukin-1 beta (IL-1 beta) and free fatty acids. Removal of glucose from the media partially inhibited IL-1 beta-stimulated nitrite (NO2-) production [8.1 +/- 0.3 vs. 4.4 +/- 0.6 nmol.(1.25 X 10(5) cells)-1.48 h-1; P < 0.01; n = 12]. The glycolytic inhibitor 2-deoxy-D-glucose (2-DG) completely inhibited IL-1 beta-stimulated NO2- production [0.7 +/- 0.5 nmol.(1.25 X 10(5) cells)-1.48 h-1; P < 0.01; n = 12]. The addition of the glycolytic end product, pyruvate, completely blocked the 2-DG inhibition of IL-1 beta-stimulated NO2- production [7.4 +/- 0.4 nmol.(1.25 X 10(5) cells)-1.48 h-1; P < 0.01; n = 12]. Pyruvate alone did not significantly enhance NO2- production in the presence or absence of glucose (n = 12). The inactive analogue 3-O-methylglucose had no effect on NO2- production (n = 12). Reverse transcription-polymerase chain reaction revealed that pyruvate blocked 2-DG inhibition of inducible NO synthase mRNA expression. Neither 2-DG nor pyruvate had any effect on GTP-cyclohydrolase I mRNA expression in CM. We report for the first time that optimal IL-1 beta-stimulated NO production by CM requires both glucose and the glycolytic end product pyruvate.

Animals↗
PubMed1996

NF-kappa B and GTP cyclohydrolase regulate cytokine-induced nitric oxide production by cardiac myocytes.

We previously reported that interleukin-1 beta (IL-1) alone stimulated nitric oxide (NO) production by neonatal rat cardiac myocytes (CM) in culture. The present studies were undertaken to explore the signal transduction pathways involved in IL-1-induced NO production by CM. Translocation from the cytosol to the nucleus of nuclear factor-kappa B (NF-kappa B) and activation of guanosine 5'-triphosphate (GTP) cyclohydrolase [rate-limiting enzyme in tetrahydrobiopterin (BH4) synthesis] have been implicated in IL-1 signaling. Accordingly, the effects of the NF-kappa B inhibitor pyrolidine dithiocarbamate (PDTC) and the GTP cyclohydrolase inhibitor 2,4-diamino-6-hydroxypyrimidine (DAHP) on IL-1-induced NO production by CM were studied. PDTC and DAHP inhibited IL-1-induced NO2-production by CM (6.7 +/- 0.6 vs. 0.9 +/- 0.3 and 0.3 +/- 0.1 nmol. 1.25 x 10(5) cells(-1).48 h-1, respectively, P < 0.01, n = 12 for each). Immunohistochemical staining revealed that PDTC blocked IL-1-stimulated nuclear translocation of NF-kappa B. The membrane-permeable analogue of the NO synthase cofactor BH4, methyl-BH4 (mBH4), only partially reversed DAHP inhibition of NO2- formation (6.7 +/- 0.6 vs. 2.4 +/- 0.3 nmol. 1.25 x 10(5) cells-1.48 h-1, P < 0.01, n = 12). Semiquantitative reverse transcription polymerase chain reaction revealed no inducible NO synthase (iNOS) mRNA production in cells treated with IL-1 + PDTC.CM treated with IL-1 + DAHP did express iNOS mRNA. We report for the first time that nuclear translocation of NF-kappa B is essential for II-1-induced iNOS mRNA expression and GTP cyclohydrolase activity is required in addition in addition to BH4 for optimal NO production by CM.

Animals↗
PubMed1995

Regulation of constitutive nitric oxide synthase activity by the human heart.

We and others have provided indirect evidence for the presence of a constitutive nitric oxide synthase (cNOS) in the mammalian heart. We now provide more direct evidence for the regulation of a myocardial cNOS in the hearts of patients undergoing elective cardiopulmonary bypass (CPB). cNOS enzyme activity was demonstrable in both cytosolic (8.3 +/- 0.02 pmol/min/mg) and membrane (11.1 +/- 0.4 pmol/min/mg) preparations derived from human atrial pectinate muscles obtained at the time of CPB (n = 6). Plasma nitrite (NO2-) + plasma nitrate (NO3-) levels from the beating hearts of patients before bypass were reduced from 146 +/- 33 to 5.1 +/- 50 pmol/min/g after cardiac arrest during CPB (n = 23; p < 0.002 by Student's t test). Thus, the human myocardium constitutively produces nitric oxide that is regulated by the contractile state of the heart.

Adult↗
PubMed1995

Cytokine-stimulated nitric oxide production inhibits mitochondrial activity in cardiac myocytes.

We have previously proposed that cytokine-stimulated nitric oxide (NO) production is responsible for reversible myocardial depression in sepsis, trauma and ischemia. NO previously has been found to inhibit mitochondrial activity in other cell types. Accordingly, we sought to determine if cytokine-stimulated NO production inhibited cardiac myocyte mitochondrial activity. Treatment of neonatal rat cardiac myocytes with interleukin-beta (IL-1) resulted in the expression of mRNA for inducible NO synthase (iNOS) and stained positively for iNOS protein by immunohistochemistry. No iNOS staining was detected in untreated cells. IL-1 treatment resulted in significant nitrite levels vs control over 48 hrs (4.2 +/- 0.7 vs 0.3 +/- 0.2 nmol/1.25 x 10(5) cells, respectively) (n = 12) that was inhibited by 1mM NMA (0.3 +/- 0.2 nmoles; p < .01; n = 12). Mitochondrial activity was assessed by the MTT colorimetric assay using (3-4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide and OD 570-630. Mitochondrial activity was significantly inhibited by IL-1 vs control cells (0.436 +/- 0.01 vs 0.608 +/- 0.03) and reversed by 1mM NMA (0.549 +/- 0.03) or removal of IL-1 (0.662 +/- 0.02) (p < .01; n = 12 for each). These data strongly suggest that cytokine-stimulated NO production by cardiac myocytes results in reversible inhibition of mitochondrial activity.

Animals↗
PubMed1995

A longitudinal study of functional disability in a national cohort of patients with polymyositis/dermatomyositis.

OBJECTIVE: To analyze changes in functional status and the factors contributing to disability in a national inception cohort of 257 patients with polymyositis/dermatomyositis (PM/DM). METHODS: Data were gathered from patients' self-reports on questionnaires: one concerning disease- and treatment-related complications, and the other concerning disability, as reflected by a disability index (DI) derived from the Health Assessment Questionnaire (HAQ). RESULTS: Based on certain characteristics that differentiated disability patterns, 3 groups of patients were identified. Group 1 patients (n = 153) were < or = 60 years old and never had avascular necrosis (AVN) or a vertebral compression fracture (CF), Group 2 patients were > 60 and never had AVN or a vertebral CF, and Group 3 patients reported AVN or a vertebral CF irrespective of age. As measured by the HAQ DI, disability increased very gradually over time in Group 1 patients and more rapidly in Group 2 and Group 3 patients. The increase in disability in patients experiencing AVN was greater than that in patients with similar pre-AVN disease characteristics who did not develop AVN (P = 0.003). CONCLUSION: In this prospective study of disease course and iatrogenic factors related to functional disability in PM/DM, the HAQ DI increased with disease duration. Corticosteroid-related morbidity, as reflected by the development of AVN or CF, significantly contributed to patient-reported functional disability.

Adult↗
PubMed1995

Inflammatory myopathies.

New information regarding myositis specific autoantibodies, histopathologic analysis of muscle biopsy specimens, and immunogenetic features of the different serologic subsets of disease has greatly increased our understanding of the pathogenesis of the inflammatory myopathies. The clinical descriptions of inclusion body myositis and 'amyopathic dermatomyositis' (Euwer and Sontheimer, 1993) are examples of our expanded descriptive capabilities in the evaluation of patients with myopathy. Finally, newer techniques such as cytokine analysis and magnetic resonance imaging may help in the ongoing assessment of disease activity in patients with myositis. The combination of these recently described clinical and laboratory parameters are enough to force a reconsideration of the previously described classification and diagnostic criteria in the inflammatory myopathies.

Dermatomyositis↗
PubMed1995

Cytokine induction during cardiac surgery: analysis of TNF-alpha expression pre- and postcardiopulmonary bypass.

Cytokines are soluble mediators that possess both intra- and intercellular signaling properties. Their function has been investigated most thoroughly in the context of immune reactions. Cytokines, however, form an important component of the inflammatory response to trauma and are found in elevated concentrations following cardiopulmonary bypass (CPB). We were, therefore, interested in studying mRNA expression for the cytokine tumor necrosis factor alpha (TNF-alpha) in patients undergoing cardiac surgery. White cells isolated from the circulation of seven patients before and after CPB were assayed for the expression of mRNA with TNF-alpha specific primers using the polymerase chain reaction. Message for TNF-alpha was found in all patients, with the highest values demonstrated in patients whose CPB times exceeded 1 1/2 hours. Enhanced message expression was seen as early as 1 hour after the start of CPB. Genes responsible for cytokine (TNF-alpha) expression and production are activated during cardiac surgery.

Base Sequence↗
PubMed1995

cAMP enhances inducible nitric oxide synthase mRNA stability in cardiac myocytes.

The effects of adenosine 3',5'-cyclic monophosphate (cAMP) on cardiac myocyte nitric oxide (NO) production were studied. Maximal nitrite (NO2(-)) production by cultured neonatal rat cardiac myocytes was achieved with 500 U/ml interleukin-1 beta (IL-1 beta) for 48 h (4.6 +/- 0.3 nmol/1.25 x 10(5) cells; n = 12). Cardiac myocytes exposed to 500 U/ml IL-1 beta for 48 h stained positively for inducible nitric oxide synthase (iNOS) by immunohistochemistry. Forskolin (FSK; adenylate cyclase stimulator) or dibutyryl cAMP (DBcAMP; membrane-permeable cAMP analogue) administration alone had no effect on NO2(-) production. The addition of FSK or DBcAMP to IL-1 beta significantly increased NO2-) levels vs. IL-1 beta alone (9.7 +/- 0.6 and 10.9 +/- 0.8 vs. 4.6 +/- 0.3 nmol/1.25 x 10(5) cells per 48 h, respectively; P < 0.01; n = 12). Semiquantitative reverse transcriptase-polymerase chain reaction revealed increased iNOS mRNA in myocytes treated with FSK+IL-1 beta or DBcAMP+IL-1 beta vs. those treated with IL-1 beta alone. The addition of FSK or DBcAMP to IL-1 beta increased iNOS mRNA half-life over IL-1 beta treatment alone (10.6, 11.7 vs. 2.4 h, respectively). Cardiac myocytes do not express iNOS in response to cAMP alone. Rather, cAMP enhances iNOS mRNA stability following cytokine exposure.

Animals↗
PubMed1995

Nitric oxide synthase inhibitor alters papillary muscle force-frequency relationship.

We provide evidence for an immediate effect of NG-monomethyl-L-arginine (L-NMMA) on the force-frequency relationship in isolated hamster papillary muscles. L-NMMA (competitive inhibitor of nitric oxide synthase) reversed the force-frequency relationship (staircase effect) in isolated hamster papillary muscles from negative to positive (P < .01; ANOVA; n = 6). The addition of L-arginine (substrate for nitric oxide synthase) blocked the L-NMMA effect (P < .01; ANOVA; n = 6). The addition of the nitric oxide (NO) donor, sodium nitroprusside (NTP), significantly increased the level of cGMP in the tissue bath (P < .01; test; n = 6) and reversed the positive inotropic effect of L-NMMA on staircase (P < .01; ANOVA; n = 6). The addition of 8-Br-cGMP to the bath resulted in a concentration-dependent decrease in tension generated by the papillary muscles (n = 6). Methylene blue (known inhibitor of cGMP) mimicked the effect of L-NMMA on staircase (P < .01; ANOVA; n = 6). L-NMMA also significantly blunted the negative inotropic effect of ryanodine (SR calcium release channel regulator) (P < .01; ANOVA; n = 6). The positive inotropic effect of Bay K 8644 (sarcolemmal, L-type calcium channel regulator) was not affected by L-NMMA (P = NS; ANOVA; n = 6). L-NMMA had no effect on either [3H]ryanodine or [3H]PN200-110 (sarcolemmal, L-type calcium channel regulator) binding to cardiac membranes. These findings support a cGMP-dependent role for endogenous NO in myocardial E-C coupling.

Amino Acid Oxidoreductases↗
PubMed1994

Chronotropic effects of cytokines and the nitric oxide synthase inhibitor, L-NMMA, on cardiac myocytes.

We and others have proposed that cytokine-stimulated nitric oxide (NO) production is responsible for reversible myocardial depression in sepsis, trauma and ischemia. An effect of NO on cardiac sarcolemmal L-type calcium channels has also recently been proposed. The spontaneous beating rate of neonatal cardiac myocytes is regulated by the sarcolemmal L-type calcium channel. Accordingly, we sought to determine if cytokine-stimulated NO production could also regulate beating rates of neonatal cardiac myocytes. Treatment of neonatal rat cardiac myocytes with TNF, IL-1, IL-6, 10(-5)M NMA, or 10(-3)M NMA significantly enhanced spontaneous beating rates compared to untreated myocytes in serum-free media for 48 hours (p < or = .01; n = 12 for each). Only IL-1 treatment resulted in significant nitrite levels vs. control over 48 hours (4.2 +/- 0.7 vs. 0.3 +/- 0.2 nmoles/1.25 x 10(-5) cells, respectively) (n = 12). Nitrite production by IL-1 was inhibited by 10(-3)M NMA but not 10(-5)M NMA (0.3 +/- 0.2 vs. 4.1 +/- 0.6 nmoles; p < .01; n = 12). The addition of 10(-5)M NMA to TNF, IL-1, and IL-6 did not alter the effect of the cytokines on the spontaneous beating rates of the cardiac cells (p < or = .01; n = 12 for each). These results strongly suggest that cytokines and NMA affect cardiac myocyte spontaneous beating rates through mechanisms independent of NO.

Amino Acid Oxidoreductases↗
PubMed1994

Catalytic conversion of L-arginine to nitrate by platinum electrodes.

Platinum electrodes (PLE) have been used recently to study the physiologic effects of the enzymatic conversion of L-arginine (L-arg) to nitric oxide (NO) by nitric oxide synthase (NOS). We sought to determine if PLE alone could catalytically convert L-arg to NO without NOS. Accordingly, NO2- + NO3- levels (NOx) were measured by HPLC from a physiologic Tyrode's buffer in the presence and absence of electrical stimulation with PLE or silver chloride electrodes (SCE) for 10 min (n = 6 for each condition). PLE stimulated at 1Hz produced 24 +/- 0.7 and 15.4 +/- 2.8 microM NOx from D-arg and L-arg (100mM) respectively. PLE + L-arg stimulated from 0 to 5 Hz produced increasing NOx (2.9 +/- 0.27;15.4 +/- 2.8;19.7 +/- 4;32 +/- 5;37 +/- 6.2;43 +/- 7 microM). SCE+L-arg showed no increase in NOx above background. The addition of 1% BSA to the Tyrode's buffer further increased NOx levels. NO2- levels were undetectable, indicating all NOx levels were NO3-. We conclude that PLE can catalytically convert L-Arg to NO3- via electron transfer without NOS.

Arginine↗
PubMed1994

A potential role for nitric oxide in myocardial stunning.

Nitric oxide (NO) production by the human heart has been demonstrated in patients undergoing cardiac surgery. Similar to what has been described in other species, a basal production of NO by the human heart is seen (126 +/- 42 pmol/min per gram). Following reperfusion, at the end of the procedure, the level of NO production increases significantly reaching concentrations of 1430 +/- 330 pmol/min per gram. Increased activity for the enzyme NO synthase (NOS) (8.0 +/- 1.2 pmol/mg prebypass vs 26.4 +/- 4.8 pmol/mg postbypass) coincides with changes in NO production and occurs at a time when myocardial stunning is clinically detectable. The significance of these findings is discussed and suggest a role for NO in the pathophysiology of myocardial stunning.

Amino Acid Oxidoreductases↗
PubMed1994

Therapy of inflammatory myopathy.

The management of the muscular and extramuscular manifestations of the inflammatory myopathies remains a challenge for the practicing rheumatologist. Although corticosteroids remain the first line of therapy, their side effects often limit their usefulness. Paradoxically, one of the side effects of steroids, muscle weakness, is the very symptom at which therapy is aimed. Other immunosuppressive agents are of proven benefit alone or in combination with corticosteroids. The identification of characteristic autoantibodies that identify poor prognostic outcomes and the availability of newer immunosuppressive regimens should contribute to a more aggressive but perhaps safer therapeutic approach to the patient with myositis.

Humans↗
PubMed1993

Verapamil regulation of a defective SR release channel in the cardiomyopathic Syrian hamster.

The Bio 14.6 Cardiomyopathic Syrian Hamster (CMH) has an autosomal recessive disease characterized by intracellular calcium overload, cardiac and skeletal myopathies and premature death from congestive heart failure. Early treatment of these animals with the calcium antagonist, verapamil (V), prevents the development of the disease. We have previously provided evidence supporting a specific defect in the ryanodine-sensitive SR calcium release channel (SRCRC) in CMH. We now provide physiologic and biochemical evidence that V modulates SRCRC. Papillary muscles prepared from F1B control hamsters (F1B) revealed an enhanced inotropic responsiveness to V and ryanodine (R) with age, not seen with CMH. CMH papillary muscles demonstrated paradoxical positive inotropic effects of V and R not shared with F1B. The positive inotropic effects of V and R were not additive. V enhanced the affinity (decreased KD) of [3H]ryanodine binding to cardiac membranes. Thus, V may prevent the overt manifestations of genetic disease in CMH by modulating a defective ryanodine-sensitive SR release channel.

Animals↗