RESUMO
Objective: To investigate the value of plasma cells for diagnosing lymph node diseases. Methods: Common lymphadenopathy (except plasma cell neoplasms) diagnosed from September 2012 to August 2022 were selected from the pathological records of Changhai Hospital, Shanghai, China. Morphological and immunohistochemical features were analyzed to examine the infiltration pattern, clonality, and IgG and IgG4 expression of plasma cells in these lymphadenopathies, and to summarize the differential diagnoses of plasma cell infiltration in common lymphadenopathies. Results: A total of 236 cases of lymphadenopathies with various degrees of plasma cell infiltration were included in the study. There were 58 cases of Castleman's disease, 55 cases of IgG4-related lymphadenopathy, 14 cases of syphilitic lymphadenitis, 2 cases of rheumatoid lymphadenitis, 18 cases of Rosai-Dorfman disease, 23 cases of Kimura's disease, 13 cases of dermal lymphadenitis and 53 cases of angioimmunoblastic T-cell lymphoma (AITL). The main features of these lymphadenopathies were lymph node enlargement with various degrees of plasm cell infiltration. A panel of immunohistochemical antibodies were used to examine the distribution of plasma cells and the expression of IgG and IgG4. The presence of lymph node architecture could help determine benign and malignant lesions. The preliminary classification of these lymphadenopathies was based on the infiltration features of plasma cells. The evaluation of IgG and IgG4 as a routine means could exclude the lymph nodes involvement of IgG4-related dieases (IgG4-RD), and whether it was accompanied by autoimmune diseases or multiple-organ diseases, which were of critical evidence for the differential diagnosis. For common lesions of lymphadenopathies, such as Castleman's disease, Kimura's disease, Rosai-Dorfman's disease and dermal lymphadenitis, the expression ratio of IgG4/IgG (>40%) as detected using immunhistochemistry and serum IgG4 levels should be considered as a standard for the possibility of IgG4-RD. The differential diagnosis of multicentric Castleman's diseases and IgG4-RD should be also considered. Conclusions: Infiltration of plasma cells and IgG4-positive plasma cells may be detected in some types of lymphadenopathies and lymphomas in clinicopathological daily practice, but not all of them are related to IgG4-RD. It should be emphasized that the characteristics of plasma cell infiltration and the ratio of IgG4/IgG (>40%) should be considered for further differential diagnosis and avoiding misclassification of lymphadenopathies.
Assuntos
Hiperplasia do Linfonodo Gigante , Doença Relacionada a Imunoglobulina G4 , Linfadenite , Linfadenopatia , Humanos , Hiperplasia do Linfonodo Gigante/diagnóstico , Hiperplasia do Linfonodo Gigante/patologia , Plasmócitos/metabolismo , Plasmócitos/patologia , China , Linfadenopatia/patologia , Inflamação/diagnóstico , Inflamação/patologia , Linfonodos/patologia , Diagnóstico Diferencial , Linfadenite/diagnóstico , Linfadenite/patologia , Imunoglobulina G/metabolismoRESUMO
Objective: To preliminarily establish the multidisciplinary cooperative vaccination management model for pediatric patients with hematological and oncological diseases, and to explore its feasibility. Methods: In this prospective study a total of 150 children with hematological and oncological diseases visited immunization clinic of Shanghai Children's Medical Center from March 2017 to August 2018 were enrolled in this study. After establishing the multidisciplinary team, designing vaccination plan, staff training, implementation and quality control, a multidisciplinary immunization clinic was set up and the vaccination plan were implemented. The implementation rate of vaccination immunization, the HBsAb level and serum hepatitis B surface antibody (HBsAb) level before and after treatment, the HBsAb level and serum immunoglobulin G antibody (IgG) levels of measles, mumps, rubella (MMR) before and 6 months after immunization, the vaccine-related adverse reactions were assessed prospectively. Chi-square test or Fisher exact test was used to compare the differences of antibody level. Results: A total of 124 cases had been vaccinated as planned, with a coverage rate of 82.7%. Among these cases, the difference of HBsAb positive rate before and after treatment was significant (62.9% (78/124) vs.13.7% (17/124), χ²= 63.489, P<0.01). In 64 cases that completed three doses of hepatitis B immunization, there was a significant difference in HBsAb positive rate before and 6 months after immunization (6.3% (4/64) vs. 98.4% (63/64), P<0.01). In 40 cases that completed MMR immunization, the IgG antibody positive rate for measles (22.5% (9/40) vs. 82.5% (33/40), χ²=31.746,P<0.01), mumps (22.5% (9/40) vs.82.5% (33/40), χ²=28.872,P<0.01), rubella (25.0% (10/40) vs.62.5% (25/40), χ²=11.429, P<0.01) before and 6 months after immunization were significantly different. Of the 421 doses of immunization, 25 (5.9%) doses reported controlled systemic or local adverse event. Conclusions: The immunization of pediatric patients with hematological and oncological diseases is of great importance. The newly-developed multidisciplinary cooperation immunization model for Chinese children with hematological and oncological diseases is feasible, and the immunization protocol is safe and has a certain effect.
Assuntos
Sarampo , Caxumba , Anticorpos Antivirais , Criança , China , Humanos , Lactente , Vacina contra Sarampo-Caxumba-Rubéola , Estudos Prospectivos , VacinaçãoRESUMO
Objective: To evaluate the clinicopathologic characteristics and outcomes of HIV-negative plasmablastic lymphoma (PBL) . Methods: Medical records of 15 patients diagnosed with HIV-negative PBL in Changhai Hospital between January 2013 and August 2019 were reviewed, and clinicopathologic characteristics and outcomes were analyzed. Results: Median age was 59 years (range: 17-69) . All patients had extranodal involvement. According to the Cotswolds-modified Ann Arbor staging system, 1 (6.7%) , 2 (13.3%) , 3 (20.0%) , and 9 (60.0%) patients were classified as at â ,â ¡,â ¢ and â £, respectively. Plasmablast and immunoblast proliferations were typical manifestations of PBL. Immunohistochemical staining showed tumor cells were diffusely positive for plasma cell markers CD38, CD138, and Mum-1, while negative for B cell markers CD20, CD10, PAX-5, and BCL-6. Median Ki-67 index was 80% (70%-90%) . Epstein-Barr virus-encoded RNA (EBER) expression was detected in 3 patients, and 1 of them was positive. All patients received chemotherapy, 80% combined with bortezomib as the first line, and responses were observed in 8 patients (6 complete and 2 partial responses) . Median progression-free survival (PFS) and overall survival (OS) were 6.8 (95% CI 2.5-11.1) months and 17.9 (95% CI 5.6-30.2) months, the 3-year PFS and OS rates were 21.2% (95% CI 1.4%-56.8%) and 38.5% (95% CI 12.0%-65.0%) , respectively. Conclusion: HIV-negative PBL with high invasiveness is extremely prone to extranodal involvement and most patients were at the advanced stage. Patients receiving an intensive therapy combined with bortezomib and bridged autologous stem cell transplantation may improve long-time survival.
Assuntos
Linfoma Plasmablástico , Adolescente , Adulto , Idoso , Infecções por HIV , Transplante de Células-Tronco Hematopoéticas , Humanos , Pessoa de Meia-Idade , Análise de Sobrevida , Transplante Autólogo , Adulto JovemRESUMO
A 54-year-old man was admitted to respiratory department with chief complaints of recurrent cough and dyspnea. Chest imaging showed multiple patchy shadows and interstitial changes. Evidence of infectious diseases was not definite, and antibiotic treatments were not effective. In the meantime, myelodysplasia syndrome was diagnosed with pancytopenia. The pathologic findings of transbronchoscopic lung biopsyshowed chronic inflammatory interstitial changes, suggesting a clinical diagnosis of organizing pneumonia. After glucocorticoids treatment, his condition aggravated. The second percutaneous lung biopsy showed the infiltration of a large number of neutrophils. Therefore, the final diagnosis of myelodysplasia syndrome with Sweet syndrome was made. Then glucocorticoids and supportive treatment were given This case may improve physicians' understanding of myelodysplasia syndrome complicated with Sweet syndrome.
Assuntos
Doenças Pulmonares Intersticiais/diagnóstico por imagem , Pulmão/patologia , Síndromes Mielodisplásicas/diagnóstico , Neutrófilos/patologia , Síndrome de Sweet/diagnóstico , Broncoscopia , Tosse/etiologia , Dispneia/etiologia , Glucocorticoides/uso terapêutico , Humanos , Pulmão/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Síndromes Mielodisplásicas/complicações , Síndromes Mielodisplásicas/tratamento farmacológico , Pancitopenia/diagnóstico , Pneumonia , Síndrome de Sweet/complicações , Síndrome de Sweet/tratamento farmacológico , Resultado do TratamentoRESUMO
Objective: To investigate the histological features and prognostic factors of angioimmunoblastic T-cell lymphoma (AITL). Methods: The pathological data of 62 patients with AITL with complete follow-up information were retrospectively collected and analyzed from Changhai Hospital during September 2012 and September 2017. Histological and immunohistochemical (IHC) examination, in situ hybridization (ISH), and single nucleotide polymorphisms (SNP) gene mutation analysis were done. Subgroup evaluation with histology, IHC, ISH, SNP gene mutation, and association with clinical progression were performed. Results: The cohort included 62 cases of AITL, including 46 males and 16 females patients, with a median age of 64 years. Follicular dendritic cells (FDC) area showed significantly expansion (≥30%) in 40 cases; increased plasma cells (≥10%) was seen in 37 cases; B cells were distributed around blood vessels in 37 cases; and increased p53 mutation positive cells (≥40%) were seen in 39 cases; high Ki-67 index (≥40%) was seen in 39 cases; RHOA mutation was seen in 19 cases; TET2 mutation was seen in 9 cases. Overall survival analysis showed these factors were significantly correlated with tumor prognosis (P<0.05). Multivariate analysis showed that CD38 positive cells<10%, Ki-67≥40%, RHOA and TET2 mutations were risk factors associated with overall survival. Conclusions: AITL could be divided into two different prognostic groups, low-grade and high-grade, with statistically significance outcome, based on the FDC area expansion, degree of plasma cell proliferation, B cells distribution pattern combined with gene mutations and clinical progression. Low-grade malignant group progresses slowly, and high-grade malignant group is highly invasive.
Assuntos
Linfadenopatia Imunoblástica/patologia , Linfoma de Células T/patologia , Proteínas de Ligação a DNA/genética , Células Dendríticas , Dioxigenases , Feminino , Humanos , Linfadenopatia Imunoblástica/diagnóstico , Hibridização In Situ , Linfoma de Células T/diagnóstico , Masculino , Pessoa de Meia-Idade , Plasmócitos , Polimorfismo de Nucleotídeo Único , Prognóstico , Proteínas Proto-Oncogênicas/genética , Estudos Retrospectivos , Proteína rhoA de Ligação ao GTP/genéticaRESUMO
Objective: To evaluate the clinicopathologic features of Rosai-Dorfman disease (RDD) , and elucidate the potential pathogenesis by whole exome sequencing (WES) . Methods: Clinico-pathological data of 23 RDD patients diagnosed between 2010 and 2018 in Changhai hospital were reviewed, and 9 paraffin-embedded specimens were performed for WES. Results: The median age of 23 RDD patients was 47 (10-79) years. Of them, 19 cases had extranodal lesions, 3 had nodal lesions, and 1 had nodal and extranodal lesions coincidently. All patients received surgery for lesion resection. Histiocytosis in lymph node sinuses or in extranodal tissues accompanied by lymphocyte phagocytosis are typical pathological features of RDD. Immunohistochemical staining shows histocytes are positive for S100, CD68 and CDl63, and negative for CD1a. mTOR, KMT2D and NOTCH1 mutations were detected with WES in these cases. Conclusion: Mutations in mTOR, KMT2D and NOTCH1 genes may be involved in the pathogenesis of RDD, and their clinical significance needs to be further studied.
Assuntos
Histiocitose Sinusal , Adolescente , Adulto , Idoso , Criança , Humanos , Pessoa de Meia-Idade , Sequenciamento do Exoma , Adulto JovemRESUMO
A novel nude mice model of human extranodal nasal type NK/T-cell lymphoma was established by subcutaneously implanting the sample taken from the patient with secondary extranodal nasal type NK/T-cell lymphoma of the stomach into the right axillary region of a BALB/c (nu/nu) nude mouse. This model had been successfully transplanted in vivo for thirty-two generations with a stable growth cycle. The survival rates of both resuscitation and transplantation were 100%. Histologically, the tumor cells were medium to large size and arranged in sheets, with a little mesenchyma, and disseminated almost in all passages of the lymphoma-bearing nude mice. Immunologically, the tumor cells were positive for CD56, cytoplasmic CD3, granzyme B or TIA-1 and LMP1, sometimes for CD8 but negative for surface CD3, CD7, CD20 and CD1a. EBER1/2 was found. No T-cell receptor gamma gene rearrangement was detected in the transplanted tumors. Furthermore, both human sequencing-tagged sites SY14 and Y chromosome were detected by PCR or fluorescent in situ hybridization, respectively, in the transplanted tumor. The transplanted tumor in this novel nude mice model maintained the essential features of human extranodal nasal type NK/T-cell lymphoma, and it would be an ideal tool in vivo for further research of the tumor.
Assuntos
Modelos Animais de Doenças , Células Matadoras Naturais , Linfoma de Células T/patologia , Neoplasias Nasais/patologia , Animais , Evolução Fatal , Feminino , Humanos , Imunofenotipagem , Hibridização in Situ Fluorescente , Linfoma de Células T/imunologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Pessoa de Meia-Idade , Neoplasias Nasais/imunologiaRESUMO
To test the role of inorganic phosphate (Pi) in downregulation of myocardial contractile force at the onset of ischemia, Pi of rat hearts was determined with 31P nuclear magnetic resonance spectroscopy. Forty cycles of brief hypoperfusion (30% of baseline flow for 33 s) were used to achieve a time resolution of 0.512 s for comparing dynamic changes in Pi and contractile force. Initial control values of left ventricular developed pressure (LVP), heart rate, and oxygen consumption were 136 +/- 11 mmHg, 236 +/- 4 beats/min, and 95 +/- 3 microl O2 x min(-1) x g(-1); these values were unchanged at the end of the experiment. During the first 10 s of hypoperfusion, Pi increased at a rate (percentage of the total observed change) faster than the decrease in LVP; Pi and LVP then changed at the same rate during the remainder of the hypoperfusion. ADP did not change in advance of LVP. Intracellular pH did not change. The results indicate that Pi plays an important role in initiating the downregulation of myocardial contractile force at the onset of ischemia. Perfusion pressure also declined faster than LVP at the onset of ischemia, indicating potential importance of vascular collapse in contractile downregulation during early ischemia.
Assuntos
Hemodinâmica , Contração Miocárdica , Isquemia Miocárdica/fisiopatologia , Miocárdio/metabolismo , Fosfatos/metabolismo , Difosfato de Adenosina/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Citosol/metabolismo , Frequência Cardíaca , Técnicas In Vitro , Espectroscopia de Ressonância Magnética , Isquemia Miocárdica/metabolismo , Reperfusão Miocárdica , Consumo de Oxigênio , Fosfocreatina/metabolismo , Fósforo , Ratos , Fatores de Tempo , Função Ventricular EsquerdaRESUMO
This study evaluated cytosolic P(i) as an independent regulator of cardiac adenosine formation by dissociating changes in P(i) from changes in AMP and ADP. Myocardial high-energy phosphates (HEP), measured by (31)P nuclear magnetic resonance spectroscopy, were depleted acutely by perfusing isolated guinea pig hearts with 2-deoxyglucose (2-DG), and the effects of 2-DG were compared with a norepinephrine infusion producing similar changes in HEP. 2-DG treatment resulted in lower adenosine release (R(ado)) (54 +/- 18 vs. 622 +/- 199 pmol x min(-1) x g(-1)) and P(i) concentration ([P(i)]) (0.5 +/- 0.1 vs. 6.0 +/- 0.9 mM) than norepinephrine despite similar AMP concentration ([AMP]). Chronic phosphocreatine depletion produced by beta-guanidinopropionic acid feeding also reduced R(ado) and P(i) during hypoxia. Replacement of perfusate glucose and pyruvate with acetate increased R(ado) (from 39 +/- 12 to 356 +/- 100 pmol x min(-1) x g(-1)) and [P(i)] (from 2.0 +/- 0.5 to 5.1 +/- 0.6 mM) with no change in cytosolic [AMP]. Adenosine kinase isolated from guinea pig hearts was inhibited by [P(i)] values seen during hypoxia or hypoperfusion. We conclude that cytosolic [P(i)] can be an important regulator of cardiac adenosine formation through inhibition of adenosine kinase.
Assuntos
Adenosina/biossíntese , Miocárdio/metabolismo , Fosfatos/fisiologia , Acetatos/farmacologia , Adenosina/metabolismo , Adenosina Quinase/metabolismo , Monofosfato de Adenosina/metabolismo , Animais , Desoxiglucose/farmacologia , Metabolismo Energético/efeitos dos fármacos , Guanidinas/farmacologia , Cobaias , Hemodinâmica/efeitos dos fármacos , Técnicas In Vitro , Espectroscopia de Ressonância Magnética , Masculino , Fosfatos/metabolismo , Propionatos/farmacologiaRESUMO
OBJECTIVE: This study tested the hypothesis that endogenous adenosine depresses anaerobic glycolysis in preischaemic and moderately ischaemic myocardium. METHODS: Isolated, working guinea-pig hearts, perfused with glucose-fortified Krebs-Henseleit buffer, were subjected to 15 min mild hypoperfusion (coronary flow 60% of baseline) followed by 10 min ischaemia (coronary flow 20% of baseline). Adenosine A1 receptors were blocked with 8-p-sulfophenyl theophylline (8-SPT; 20 microM). Glucose oxidation and lactate production from exogenous glucose were assessed from 14CO2 and [14C]lactate formation, respectively, from [U-14C]glucose. Energy metabolites, glycolytic intermediates and glycogen were measured in extracts of stop-frozen preischaemic, mildly hypoperfused and ischaemic myocardium. RESULTS: Adenosine receptor blockade did not affect left ventricular function assessed from heart rate x pressure product and pressure x volume work although coronary flow was slightly reduced. Adenosine receptor blockade increased glucose uptake (P < 0.05) by 100% during preischaemia and by 74% during mild hypoperfusion, and increased lactate production from exogenous glucose (P < 0.05) by 89% during preischaemia and fourfold during mild hypoperfusion, but did not stimulate glucose oxidation under any condition. Glycogen degradation was not increased by adenosine receptor blockade during ischaemia. Crossover plots of glycolytic intermediates revealed that phosphofructokinase was activated by adenosine receptor blockade at all three levels of perfusion. CONCLUSION: Endogenous adenosine attenuates anaerobic glycolysis in normally perfused, hypoperfused and ischaemic myocardium by blunting phosphofructokinase activity; this effect is mediated by adenosine A1 receptors.
Assuntos
Isquemia Miocárdica/metabolismo , Miocárdio/metabolismo , Antagonistas de Receptores Purinérgicos P1 , Teofilina/análogos & derivados , Adenosina/metabolismo , Animais , Ativação Enzimática , Glucose/metabolismo , Glucose/farmacologia , Glicogênio/metabolismo , Glicólise/efeitos dos fármacos , Cobaias , Técnicas In Vitro , Ácido Láctico/metabolismo , Isquemia Miocárdica/fisiopatologia , Oxirredução , Perfusão , Fosfofrutoquinase-1/metabolismo , Teofilina/farmacologia , Função Ventricular EsquerdaRESUMO
Adrenergic receptor blockade has been reported to decrease cardiac adenosine formation and release during hypoxia. We wished to determine whether this occurs by an improvement in the energy supply/demand ratio. Isolated guinea pig hearts were perfused at a constant pressure of 50 mm Hg. Hypoxia (30% O2) was maintained for 20 min while adenosine release and venous PO2 were measured in the coronary venous effluent. beta-adrenergic blockade with 5 microM atenolol did not change hypoxic adenosine release (Control: 15.6 +/- 2.7, Atenolol: 23.6 +/- 5.7 nmol/g/20 min). Addition of 6 microM phentolamine with atenolol significantly reduced hypoxic adenosine release (4.4 +/- 1.4 nmol/g/20 min, P < 0.05). Atenolol was without hemodynamic effects, but addition of phentolamine reduced left ventricular pressure development, heart rate, and oxygen consumption prior to hypoxia. Atenolol plus phentolamine did not change venous PO2 during hypoxia. Treatment with phenoxybenzamine (1 microM) plus atenolol also reduced adenosine release (7.4 +/- 0.8 nmol/g/20 min). Control experiments and atenolol plus phentolamine experiments were repeated using 31P-NMR to measure high energy phosphates. Adrenergic blockade had no effect on phosphate concentrations during normoxia, but resulted in higher [PCr], lower [P(i)] and higher phosphorylation potentials during hypoxia. Adrenergic blockade also prevented the hypoxia-induced rise in intracellular [H+], [AMP] and [ADP] seen in control hearts. The changes in phosphorylation potential are correlated with similar changes in adenosine release in adrenergically intact hearts. We conclude that the primary effect of adrenergic blockade during hypoxia is a reduction in ATP use due to alpha-receptor blockade. This leads to improved high energy phosphate concentrations during hypoxia and a reduction in adenosine formation.
Assuntos
Adenosina/biossíntese , Atenolol/farmacologia , Hipóxia/metabolismo , Fosfatos/metabolismo , Animais , Cobaias , Técnicas In Vitro , Espectroscopia de Ressonância Magnética , Masculino , Fenoxibenzamina/farmacologia , Fentolamina/farmacologia , FósforoRESUMO
Cardiac adenosine release is thought to depend on the oxygen supply/demand ratio, and this effect may be mediated by changes in high energy phosphate concentrations. Previous studies supporting this hypothesis have been done primarily in isolated hearts. We tested this hypothesis in intact dog hearts. Anesthetized, open-chest dogs were placed in a 4.7-T magnet where 31P nuclear magnetic resonance spectra were acquired via a surface coil over the heart at 2-minute intervals (60 scans, 2-second interpulse delay). Coronary sinus flow was shunted through a flow probe and returned via a jugular vein. After a control period, intracoronary norepinephrine was infused (12 micrograms/min) for 16 minutes and plasma samples were taken every 5 minutes. The phosphocreatine/ATP peak area ratio was used as an index of high energy phosphate changes. During norepinephrine infusion, arterial pressure, heart rate, coronary sinus flow, oxygen consumption, and adenosine release all increased significantly. Adenosine release peaked at 5 minutes but remained elevated after 15 minutes. There was a transient fall in the phosphocreatine/ATP ratio (9.2 +/- 3.1%, p less than 0.05) during the first 7 minutes, but the ratio returned to control levels by 9 minutes. The oxygen supply/consumption ratio increased after 5 minutes of norepinephrine infusion and then returned to control levels. We conclude that during norepinephrine infusion in vivo, persistent adenosine release can occur with only small transient changes in high energy phosphate concentrations and with no decrease in the oxygen supply/demand ratio.
Assuntos
Trifosfato de Adenosina/metabolismo , Adenosina/metabolismo , Miocárdio/metabolismo , Norepinefrina/farmacologia , Fosfocreatina/metabolismo , Animais , Circulação Coronária , Vasos Coronários , Cães , Coração/efeitos dos fármacos , Hemodinâmica , Infusões Parenterais , Espectroscopia de Ressonância Magnética , Modelos Cardiovasculares , Norepinefrina/administração & dosagem , Fatores de TempoRESUMO
The purpose of this study was to examine adenosine release and high-energy phosphate concentrations during norepinephrine (NE) infusion in isolated guinea pig hearts perfused with a physiological salt solution (PSS) containing erythrocytes (RBC). Phosphate concentrations were monitored using 31P-nuclear magnetic resonance spectroscopy while NE was infused at 6 x 10(-10) mol/min. Compared with perfusion with PSS alone, RBC-perfused hearts consumed more oxygen and developed higher left ventricular pressure and first time derivative of left ventricular pressure at lower coronary flow rates. Adenosine release rates were very similar with both perfusates. NE infusion did not produce a decline in ATP concentration ([ATP]) or an increase in calculated [ADP] and [AMP] in RBC-perfused hearts. However, phosphorylation potential ([ATP]/[ADP][Pi]) declined because of increased [Pi]. We conclude that NE infusion does not change adenine nucleotide concentrations in well-oxygenated guinea pig hearts and that changes in nucleotide concentrations are not necessary for increased adenosine release. Phosphorylation potential is a better predictor of adenosine release than any individual nucleotide or phosphate concentration.
Assuntos
Adenosina/biossíntese , Metabolismo Energético , Eritrócitos/metabolismo , Miocárdio/metabolismo , Adenosina/metabolismo , Animais , Metabolismo Energético/efeitos dos fármacos , Cobaias , Hemodinâmica , Técnicas In Vitro , Masculino , Norepinefrina/farmacologia , DescansoRESUMO
Previous studies using hypoperfusion and 2-deoxyglucose infusion have revealed a biphasic relationship between myocardial energy status and adenosine release (RADO). As energy charge ([ATP] + 1/2[ADP])/([ATP] + [ADP] + [AMP]) or phosphorylation potential ([ATP]/[ADP][Pi]) is lowered there is an initial increase in RADO, but RADO declines from peak levels during severe energy depletion. This study examined the hypothesis that the same pattern of RADO exists during graded hypoxia. Isolated guinea-pig hearts were perfused at constant flow and exposed to mild (30% O2) and severe (0% O2) hypoxia in the presence of norepinephrine (NE, 6 x 10(-8) M). Phosphorylation potential and energy charge were determined using 31P-NMR spectroscopy and adenosine release into coronary venous effluent was measured. Graded hypoxia lowered energy charge and phosphorylation potential, and raised RADO. Although severe hypoxia plus NE lowered energy charge and phosphorylation potential to levels equivalent to those associated with decreased RADO during hypoperfusion or 2-deoxyglucose treatment, RADO during severe hypoxia was greater than during mild hypoxia. HCl was infused during severe hypoxia in order to reproduce the low intracellular pH seen during hypoperfusion, but HCl increased RADO rather than decreasing it. We conclude that during hypoxia, RADO does not have a biphasic relationship to phosphorylation potential or energy charge, suggesting that the regulation of adenosine formation cannot be explained solely in terms of these variables. Furthermore, intracellular acidosis is not responsible for inhibiting RADO at low phosphorylation potential and energy charge during hypoperfusion because it has no effect on RADO during severe hypoxia.
Assuntos
Adenosina/metabolismo , Metabolismo Energético , Miocárdio/metabolismo , Consumo de Oxigênio , Monofosfato de Adenosina/metabolismo , Animais , Cobaias , Hemodinâmica , Concentração de Íons de Hidrogênio , Hipóxia/metabolismo , Técnicas In Vitro , Cinética , Espectroscopia de Ressonância Magnética , Masculino , Norepinefrina , FosforilaçãoRESUMO
The relationship between adenosine (Ado) formation and cytosolic energy status was studied in isolated guinea pig hearts during hypoperfusion plus norepinephrine infusion (0.6 nmol/min) and in isolated rat hearts during 2-deoxyglucose (2-DG) infusion. 31P nuclear magnetic resonance (31P-NMR) was used to measure phosphate concentrations, and both phosphorylation potential (expressed as [ATP]/[ADP][Pi]) and energy charge [expressed as (([ATP] + 1/2[ADP])/([ATP] + [ADP] + [AMP]))] were calculated as indexes of cytosolic energy status. Both progressive flow reductions and increasing length of exposure to 2-DG led to progressive decreases in energy charge and phosphorylation potential. In both cases, steady-state Ado release first increased then declined despite a continued fall in energy status. Inosine release followed a similar pattern. This biphasic pattern of Ado release vs. energy charge is similar to the pattern seen in in vitro studies of cytosolic 5'-nucleotidase, supporting the hypothesis that Ado formation in vivo is regulated by the influence of energy status on this enzyme. However, Ado release in vivo peaked at an energy charge much higher (0.997) than that observed in vitro (0.60-0.86). It is therefore probable that the inhibition of Ado formation in the perfused heart occurs via factor(s) in addition to energy charge.
Assuntos
Adenosina/biossíntese , Circulação Coronária , Desoxiglucose/farmacologia , Metabolismo Energético , Miocárdio/metabolismo , Monofosfato de Adenosina/metabolismo , Animais , Citosol/metabolismo , Cobaias , Coração/fisiologia , Inosina/metabolismo , Magnésio/metabolismo , Masculino , Norepinefrina/farmacologia , Consumo de Oxigênio , Perfusão , Fosfatos/metabolismoRESUMO
This study tested the hypothesis that adenosine released from isolated guinea pig hearts (n = 5) in response to norepinephrine is related to the cellular phosphorylation potential (PP; [ATP]/[ADP][Pi]), where Pi is inorganic phosphate. 31P-nuclear magnetic resonance (NMR) was used to measure the relative concentrations of Pi, phosphocreatine (PCr), and ATP. Hearts were Langendorff perfused with a physiological salt solution containing 0.1 mM Pi. The venous effluent was collected for measurement of adenosine and partial pressure of oxygen (PO2). After a control period, norepinephrine (6 X 10(-8) M) was infused for 20 min during which 31P-NMR spectra and samples of venous effluent were collected every minute. With norepinephrine infusion, PCr decreased rapidly to 72% of control (P less than 0.05) by 8 min and then recovered to 80% of control for the remaining 12 min. ATP fell slowly to 70% of control (P less than 0.01) over 20 min. Pi increased to a peak at 2 min (P less than 0.01), then declined slowly to a steady state (60% of the peak and 3.5 X control) from 8 to 20 min. Adenosine release increased from 11 +/- 6 to a peak of 250 +/- 68 pmol.min-1.g-1 (P less than 0.01) at 7 min and then slowly fell (P less than 0.05) to a steady state of approximately 110 pmol.min-1.g-1 (P less than 0.01 vs. control) from 10 to 20 min.(ABSTRACT TRUNCATED AT 250 WORDS)