Factor structure of the de Jong Gierveld loneliness scale: an esem approach / Estructura factorial de la “Escala de soledad de de Jong Gierveld: un modelo de ecuaciones estructurales

Esta investigación pretende examinar la fiabilidad, la validez convergente y la invariancia de la medida de la “Escala de soledad de de Jong Gierveld” (DJGLS). Se evaluó especialmente el ajuste de modelo-datos de varias estructuras factoriales en una muestra de adultos jóvenes. Los resultados demuestran que el modelo bifactorial-ESEM muestra un elevado ajuste modelo-datos, según el CFI y el RMSEA. En este caso, se ha determinado que las saturaciones cruzadas, definidas por el modelo bifactorial-ESEM, tienen un efecto creciente en el ajuste modelo-datos. En este modelo bifactorial-ESEM, la DJGLS tiene un factor general altamente fiable y dos subfactores irrelevantes. Se obtuvo la invarianza de las medidas métricas en función del sexo. Las puntuaciones de la DJGLS tuvieron correlaciones moderadas y altas, estadísticamente significativas, con variables externas. En conclusión, puede decirse que la DJGLS es un instrumento de evaluación fiable, con validez convergente y de constructo, en la muestra de adultos jóvenes. Además, la DJGLS es, básicamente, una escala unidimensional y muestra el mejor ajuste modelo-datos en el modelo bifactorial-ESEM. (AU)

Morphine and naloxone act similarly on glutamate-caused guinea pig ileum contraction.

Both morphine (M) and naloxone (NL) have been reported to have NMDA receptor blocking effects, regarded as the reason of opiate physical dependence development. On the other hand, glutamate (GLU) has been known to induce the contraction of isolated guinea pig ileum via acetylcholine release. Therefore, different concentrations of M or NL were investigated on the 1 mM GLU-induced contraction of isolated guinea pig ileum fixed at a resting tension of 1 g in isolated organ bath. The mean value (359.3 +/- 20 mg) of the GLU-elicited contraction force was significantly reduced (318.4 +/- 19.4) by 25 nM M concentration in the medium. Consequently, 500 and 750 nM M caused further decreases in a rather dose-dependent manner (270.8 +/- 17.4 and 167.8 +/- 16.5 mg, respectively). One micromolar M contraction nearly abolished (8.0 +/- 8.2 mg) the GLU-induced contraction. A similar effect was obtained with the naloxone concentrations of 10, 20, 40, and 50 microM. In addition, NL has been shown to elicit the contraction of the isolated M-dependent guinea pig ileum. In the present study, 20- and 30-microM NL concentrations in the bathing medium caused the contraction of the ileum made M-dependent by preincubation with M (333.0 +/- 32.4 and 309.5 +/- 17.7 mg, respectively). These contraction forces were significantly reduced when the NL concentration was increased to 40 microM. And, 50 microM NL concentration not only failed to induce contraction but caused a relaxation (-10.6 +/- 2.3) as well. The results were considered supporting evidence for the fact that both M and NL are NMDA receptor blockers.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of tizanidine on morphine physical dependence: attenuation and intensification.

It has previously been shown that subchronic and acute administration of L-asparaginase and glutaminase inhibitors D-Aspartic acid (D-ASP) and prolyl-leucyl-glycinamide (PLG) intensifies and attenuates morphine (M) physical dependence, respectively, by the inhibition of ASP and glutamic acid (GLU) production, and subsequently their normal releases. Tizanidine (TIZ) has long been known to be an alpha 2-adrenoceptor agonist and inhibitor of ASP and GLU release. Therefore, in this study TIZ has been administered subchronically during the development of M physical dependence to rats in which M-containing pellets had been implanted or acutely 30 min before naloxone (NL)-induced abstinence syndrome. The subchronic administration of TIZ intensified NL-precipitated abstinence syndrome whereas its acute administration attenuated it, as did D-ASP and PLG. On the other hand, TIZ added into the medium prevented the in vitro M-dependent-made guinea pig ileum from contracting following NL application. Furthermore, TIZ stopped the already started contraction by NL of the M-dependent ileum, which completely relaxed later. These effects of TIZ on M-dependent ileum were antagonized by the alpha 2-adrenoceptor antagonist yohimbine. The intensification by subchronic TIZ administration of abstinence syndrome was attributed to the lesser release of ASP and GLU, which resulted in the larger blockade of M of ASPergic/GLUergic receptors due to the lesser release of their endogenous agonist ASP and GLU and consequently the higher upregulation of the receptors. The attenuation by acute TIZ administration of NL-precipitated abstinence syndrome was explained with lesser release of ASP and GLU and concomitantly the lesser stimulation of the receptors.(ABSTRACT TRUNCATED AT 250 WORDS)