The experience of educational research at doctoral level in the region of Cuyo, Argentina

[EN] In this paper are reported the results of an exploratory-analytical research of a qualitative nature, whose intention is to approach the comprehension of the experiences, their peculiarities and problems, of a sample of students and graduates from the three doctorates in Education existing in the region of Cuyo, Argentina, which –though they reach a certain maturity– also show in these years some specific difficulties, among which the most relevant is the low rate of completion (close to 20%). The administered questionnaire, elaborated ad hoc, by means of open-ended questions, inquires on three dimensions that can explain the experience of the PhD student: 1) educational research methodology training, 2) practice in scientific research and 3) doctoral research process. The results show that curricular paths of doctorate’s research methodology, in dependence of their approach, play an important role in the process of theses, in synergy with other factors: integration into a research team, a combination of intrinsic and extrinsic motives in the choice of the topic, a more elaborated conceptualization of educational research, conceptual changes of greater importance. Among the peculiarities, one warns the primacy of the experience and/or teacher workplace in decisions concerning doctoral research; among the difficulties, stand out the lack of time and the major frequency of intrinsic difficulties to the thesis in delayed students.[ES] En este trabajo se informan los resultados de una investigación exploratorio-analítica de carácter cualitativo, cuyo propósito es acercarnos a la comprensión de las experiencias, sus particularidades y problemáticas, de una muestra de alumnos y egresados de los tres doctorados en Educación existentes en la región de Cuyo, Argentina, los que –si bien alcanzan una cierta madurez– también muestran en estos años algunas dificultades específicas, entre las cuales la más relevante es la baja tasa de finalización (cercana al 20%). El cuestionario que se administra, elaborado ad hoc, mediante preguntas abiertas, indaga sobre tres dimensiones que pueden explicar la experiencia del doctorando: 1) formación en metodología de la investigación educativa, 2) práctica en investigación científica y 3) proceso de investigación doctoral. Los resultados muestran que los trayectos curriculares de metodología de la investigación del doctorado, en dependencia de su enfoque, desempeñan un papel relevante en el proceso de tesis, en sinergia con otros factores: la inserción en un equipo de investigación, una combinación de motivos intrínsecos y extrínsecos en la elección del tema, una conceptualización más elaborada de investigación educativa, cambios conceptuales de mayor envergadura. Entre las peculiaridades, se advierte la primacía de la experiencia y/o desempeño docente en decisiones relativas a la investigación doctoral; entre las dificultades, destaca la falta de tiempo y la mayor frecuencia de dificultades intrínsecas a la tesis en los estudiantes demorados.Difabio De Anglat, H.; Portela De Nieto, A.; Gelonch Villarino, S.; Muscará, F.; Boarini De Dutto, MG. (2018). La experiencia de investigación educativa de nivel doctoral en la región de Cuyo, Argentina. 11-32. doi:10.4995/redu.2018.5690SWORD113

Antihypertensive properties of a nitric oxide-releasing naproxen derivative in two-kidney, one-clip rats.

Nonsteroidal anti-inflammatory drugs have been reported to exacerbate hypertension. In this study, we tested the hypothesis that a nitric oxide-releasing derivative of naproxen would ameliorate hypertension in the rat. Hypertension was induced by partially occluding one renal artery (the "2K,1C" model), and 2 wk later the rats started receiving naproxen, the nitric oxide-releasing derivative HCT-3012, or vehicle each day for 2 wk. Naproxen significantly exacerbated the hypertension. HCT-3012 significantly reduced blood pressure relative to both the naproxen- and vehicle-treated groups. Both naproxen and HCT-3012 markedly suppressed whole blood thromboxane B(2) synthesis. In studies of anesthetized rats, naproxen significantly enhanced the late hypertensive response to endothelin-1 and significantly blunted the early hypotensive response. In contrast, HCT-3102 did not affect either response to endothelin-1. In vitro, HCT-3012 significantly reduced the responsiveness of aortic rings to the contractile effects of phenylephrine. These studies suggest that HCT-3012 reduces blood pressure in hypertensive rats, not simply through the vasodilatory actions of the nitric oxide it releases, but through alterations in the responsiveness of the vasculature to endogenous pressor agents

Plasma Hydroxy-metronidazole/metronidazole Ratio In Patients With Liver Disease And In Healthy Volunteers.

Metronidazole pharmacokinetics were studied in patients with different degrees of liver cirrhosis, classified according to the Child-Pugh algorithm (A, B or C, as liver disease severity increases) and in schistosomic patients. Metronidazole (500 mg) was administered i.v. as a slow infusion over 20 min, and blood samples were collected at set intervals after the end of the infusion. The plasma concentrations of metronidazole and its main metabolite hydroxy-metronidazole were quantified by reversed-phase h.p.l.c. with u.v. detection. The metronidazole and hydroxy-metronidazole areas under the curve from 0 to 24 h (AUC0,24h), the metronidazole terminal elimination half-life (t1/2), the total clearance (CL), the metronidazole volume of distribution (V) values and the hydroxy-metronidazole/metronidazole concentration ratios as a function of time were calculated for each group. Comparison of the metronidazole AUC0,24h, t1/2 and CL values revealed that metronidazole metabolism is progressively impaired as the severity of liver disease increases. There were no variations in these parameters between the schistosomic and Child-Pugh A groups. In addition, there were no differences in the V and hydroxy-metronidazole AUC0,24h among the various groups studied. However, metronidazole metabolism was delayed in patients with hepatic disease, as illustrated by the hydroxy-metronidazole/metronidazole ratio 10 min after the end of metronidazole infusion. These results indicate that the clinical assessment of liver disease is paralleled by an impairment of metronidazole metabolism. Of the studied variables, we propose the hydroxy-metronidazole/metronidazole ratio 10 min after metronidazole infusion as a suitable and practical index for liver function evaluation.40477-8

Plasma hydroxy metronidazole/metronidazole ratio in anti-HCV carriers with and without apparent liver disease

Aims: To evaluate plasma hydroxy-metronidazole/metronidazole ratio as a dynamic liver function test in HCV-infected individuals with/without liver disease, in the absence of liver cirrhosis. Methods: Metronidazole was administered intravenously in healthy volunteers, asymptomatic anti-HCV-positive blood donors, and in chronic hepatitis C patients. Serology to HCV was determined by a second generation assay and confirmed by gelatin particle agglutination test using recombinant antigens C22-3 and C200. Plasma concentration of metronidazole and hydroxy-metronidazole was measured by high performance liquid chromatography in samples collected 5, 10, 20 and 30 min following the end of metronidazole infusion. Results: Chronic hepatitis C patients had abnormal liver enzymes, while healthy volunteers and anti-HCV-positive blood donors had normal liver biochemistry tests. Plasma metronidazole concentration was similar,in all groups studied. Plasma hydroxy-metronidazole/metronidazole ratio was significantly reduced in HCV-infected subjects, an effect observed 10 min after the end of drug infusion. Conclusions: Metronidazole clearance is impaired in anti-HCV-positive blood donors and chronic hepatitis C patients, indicating that HCV is capable of affecting liver function at early stages of the disease. 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Acute Inhibition Of Nitric Oxide Synthesis Induces Anxiolysis In The Plus Maze Test.

The involvement of nitric oxide (NO) in anxiety was investigated in rats, using the elevated plus maze test. Acute, but not chronic, systemic treatment with N omega-nitro-L-arginine methyl ester (L-NAME, 10 and 60 mg.kg-1), an inhibitor of NO synthase, increased the time spent by the rats in the open arms. Both the acute and chronic treatments with L-NAME inhibited NO synthase in endothelial cells and in the central nervous system, as shown by the increase in mean arterial pressure and decreased NO synthase activity in brain tissue. Chronic treatment with L-NAME also decreased the serum nitrate levels. The anxiolysis induced by acute L-NAME treatment is unlikely to be due to hypertension, since two-kidney one-clip hypertension in non-L-NAME-treated rats failed to significantly change exploratory behaviour in the elevated plus maze. These results indicate that acute inhibition of NO synthesis decreases anxiety in rats.32337-4

Upregulation Of Muscarinic Receptors By Long-term Nitric Oxide Inhibition In The Rat Ileum.

1. The aim of the present study was to examine the effects of long-term nitric oxide (NO) blockade on contractions of the rat ileum induced by muscarinic agonists. 2. Male Wistar rats received the NO synthesis inhibitor NG-nitro-l-arginine methyl ester (l-NAME; 20 mg/rat per day) in drinking water for 7, 15, 30 and 60 days. Concentration-responses curves to methacholine and carbachol were obtained and pEC50 values were calculated. Saturation binding assays were performed in membranes prepared from rat ileum after 60 days of l-NAME treatment and the dissociation constant (KD) and maximal number of binding sites (Bmax) were determined by Scatchard analysis. 3. The NO synthase activity of the ileum was markedly reduced in all l-NAME-treated groups. At 60 days after l-NAME treatment, a significant increase in the potency of methacholine (fourfold) and carbachol (threefold) was observed. In binding studies, we found a significant increase in Bmax for [3H]-quinuclidinyl benzilate of approximately 57% in the l-NAME treated group without any significant change in KD values. The contractile response to methacholine was not modified by the soluble guanylate cyclase inhibitor 1H-[1,2,4]oxadiazolo-[4,3-a]quinoxalin-1-one (3 micro mol/L). No morphological alterations in the rat ileum were observed in l-NAME-treated rats. 4. Our findings suggest that treatment with l-NAME for 60 days induces a marked increase in the potency of methacholine and carbachol, as well as an increase in receptor number in the rat ileum.30168-7