Correlation between total nitrite/nitrate concentrations and monoamine oxidase (types A and B) and semicarbazide-sensitive amine oxidase enzymatic activities in human mesenteric arteries from non-diabetic and type 2 diabetic patients

The aim of this study was to determine the correlation between total nitrite/nitrate concentrations (NOx) and the kinetic parameters of monoamine oxidase enzymes (MAO-A and MAO-B) and semicarbazide-sensitive amine oxidase (SSAO) in human mesenteric arteries. Arteries were from non-diabetic and type 2 diabetic patients with sigmoid or rectum carcinoma for whom surgery was the first option and who were not exposed to neo-adjuvant therapy. Segments of human inferior mesenteric arteries from non-diabetic (61.1 ± 8.9 years old, 7 males and 5 females, N = 12) and type 2 diabetic patients (65.8 ± 6.2 years old, 8 males and 4 females, N = 12) were used to determine NOx concentrations and the kinetic parameters of MAO-A, MAO-B and SSAO by the Griess reaction and by radiochemical assay, respectively. The NOx concentrations in arteries from diabetic patients did not differ significantly from those of the non-diabetic group (10.28 ± 4.61 vs 10.71 ± 4.32 nmol/mg protein, respectively). In the non-diabetic group, there was a positive correlation between NOx concentrations and MAO-B parameters: Km (r = 0.612, P = 0.034) and Vmax (r = 0.593, P = 0.042), and a negative correlation with the SSAO parameters: Km (r = -0.625, P = 0.029) and Vmax (r = -0.754, P = 0.005). However, in the diabetic group no correlation was found between NOx concentrations and the three kinetic parameters of the enzymes. These results suggest an important function of sympathetic nerves and vascular NOx concentrations in arteries of non-diabetic patients. Thus, these results confirm the importance of a balance between oxidants and antioxidants in the maintenance of vascular homeostasis to prevent oxidative stress.

Correlation between total nitrite/nitrate concentrations and monoamine oxidase (types A and B) and semicarbazide-sensitive amine oxidase enzymatic activities in human mesenteric arteries from non-diabetic and type 2 diabetic patients.

The aim of this study was to determine the correlation between total nitrite/nitrate concentrations (NOx) and the kinetic parameters of monoamine oxidase enzymes (MAO-A and MAO-B) and semicarbazide-sensitive amine oxidase (SSAO) in human mesenteric arteries. Arteries were from non-diabetic and type 2 diabetic patients with sigmoid or rectum carcinoma for whom surgery was the first option and who were not exposed to neo-adjuvant therapy. Segments of human inferior mesenteric arteries from non-diabetic (61.1 ± 8.9 years old, 7 males and 5 females, N = 12) and type 2 diabetic patients (65.8 ± 6.2 years old, 8 males and 4 females, N = 12) were used to determine NOx concentrations and the kinetic parameters of MAO-A, MAO-B and SSAO by the Griess reaction and by radiochemical assay, respectively. The NOx concentrations in arteries from diabetic patients did not differ significantly from those of the non-diabetic group (10.28 ± 4.61 vs 10.71 ± 4.32 nmol/mg protein, respectively). In the non-diabetic group, there was a positive correlation between NOx concentrations and MAO-B parameters: Km (r = 0.612, P = 0.034) and Vmax (r = 0.593, P = 0.042), and a negative correlation with the SSAO parameters: Km (r = -0.625, P = 0.029) and Vmax (r = -0.754, P = 0.005). However, in the diabetic group no correlation was found between NOx concentrations and the three kinetic parameters of the enzymes. These results suggest an important function of sympathetic nerves and vascular NOx concentrations in arteries of non-diabetic patients. Thus, these results confirm the importance of a balance between oxidants and antioxidants in the maintenance of vascular homeostasis to prevent oxidative stress.

Characterization of Adenosine deaminase (ADA) in hemolymph of Biomphalaria glabrata.

Adenosine is an important signaling molecule for many cellular events. Adenosine deaminase (ADA) is a key enzyme for the control of extra- and intra-cellular levels of adenosine. Activity of ADA was detected in hemolymph of B. glabrata and its optimum assay conditions were determined experimentally. The pH variation from 6.2 to 7.8 caused no significant change in ADA activity. Using adenosine as a substrate, the apparent Km at pH 6.8 was 734 micromols.L(-1). Highest activity was found at 37 degrees C. Standard assay conditions were established as being 15 minutes of incubation time, 0.4 microL of pure hemolymph per assay, pH 6.8, and 37 degrees C. This enzyme showed activities of 834 +/- 67 micromol.min(-1).L(-1) (25 degrees C) and 2029 +/- 74 micromol.min(-1).L(-1) (37 degrees C), exceeding those in healthy human serum by 40 and 100 times, respectively. Higher incubation temperature caused a decrease in activity of 20% at 43 degres C or 70% at 50 degrees C for 15 minutes. The ADA lost from 26% to 78% of its activity when hemolymph was pre-incubated at 50 degrees C for 2 or 15 minutes, respectively. Since the ADA from hemolymph presented high levels, it can be concluded that in healthy and fed animals, adenosine is maintained at low concentrations. In addition, the small variation in activity over the 6.2 to 7.8 range of pH suggests that adenosine is maintained at low levels in hemolymph even under adverse conditions, in which the pH is altered.

Characterization of adenosine deaminase (ADA) in Hemolymph of Biomphalaria glabrata

A adenosina é uma molécula sinalizadora de muitos eventos celulares. A adenosina desaminase (ADA) é enzima chave para o controle dos níveis intra e extra celulares de adenosina. A atividade da ADA foi detectada em hemolinfa de B. glabrata e suas condições ótimas de ensaio foram determinadas experimentalmente. A variação do pH de 6,2 até 7,8 não causou mudança significativa na atividade. O Km aparente foi de 734 µmoles L-1, usando adenosina como substrato. A maior atividade foi encontrada usando 37ºC como temperatura de incubação. As condições de ensaio padrão foram então estabelecidas como sendo 15 minutos de tempo de incubação, 0,4 µL de hemolinfa por ensaio, pH 6.8 e 37ºC de temperatura de incubação. A enzima apresentou atividades de 834 ± 67 µmols.min-1.L-1 (25ºC) e 2029 ± 74 µmols.min-1.L-1 (37ºC), em torno de 40 e 100 vezes maiores que os níveis encontrados em soro de humanos sadios. Em temperaturas superiores, essa atividade cai 20% a 43ºC e 70% a 50ºC, em 15 minutos. A ADA perde 26 a 78% de sua atividade quando a hemolinfa é pré-incubada a 50ºC de 2 a 15 minutos, respectivamente. Considerando os altos níveis de ADA encontrados pode-se inferir que, em animais sadios e alimentados, a adenosina é mantida em baixas concentrações na hemolinfa. Tendo a atividade da enzima permanecido constante frente à larga faixa de pH testada, sugere-se que a ADA pode atuar com eficiência mesmo em situações adversas que determinem variações no pH da hemolinfa.

Induction and modulation of the immune response to Leishmania by Montenegro's skin test.

The intradermal inoculation in naive or in previously sensitized individuals of small amounts of Leishmania extract (Montenegro's skin test) induced or modulated, respectively, the immune response to Leishmania, as assessed by subsequent Montenegro's skin tests. These phenomena could hinder the interpretation of Montenegro's skin tests in a population already subjected to the test in the past and, in addition, could affect in an unknown way the development of mucosal lesions in people infected with L. braziliensis or L. amazonensis, since those lesions have been associated with hypersensitivity to Leishmania antigens. Anti-Leishmania antibody responses, assessed by enzyme-linked immunosorbent assay, were not induced in naive individuals by Montenegro's skin tests, but tended to become more intense following these tests in previously sensitized individuals.

Hypertension and economic activities in São Paulo, Brazil.

A study of the prevalence of hypertension was undertaken among workers in 10 subsectors of the economy in São Paulo, a major urban-industrial area of Brazil. Included in the study were 5500 subjects 15-65 years of age, employed in 57 randomly selected firms. Hypertension rates (DBP greater than or equal to 90 mm Hg) were higher among males up to 44 years of age. There was a decreasing gradient from mild to moderate and severe forms in all groups. Severity tended to increase with age in all groups. Black males showed higher rates than whites (29.2% vs 16.7%, p less than 0.05), the excess being partially accounted for by moderate and severe forms (40% vs 20%). Subjects who overworked showed a trend toward higher hypertension rates. Higher rates in four subsectors (metallurgy, finance, transport, and journalism), aside from the distribution of known risk factors and job selection, may reflect a variety of work-related stressors.