Testing metabolic cold adaptation and the climatic variability hypothesis in two latitudinally distant populations of a supratidal water beetle.

Temperature significantly impacts ectotherm physiology, with thermal tolerance and metabolic traits typically varying with latitude across species ranges. The drivers of this variation remain unclear, however, despite obvious consequences for population persistence and conservation in the face of ongoing global change. This study explored local adaptation and phenotypic plasticity of metabolic rates and thermal limits in the supratidal rockpool beetle Ochthebius lejolisii. Using populations from localities at different ends of the species range that experience contrasting thermal variability, we simultaneously tested two of the major paradigms of spatial physiological ecology: metabolic cold adaptation (MCA) and the climatic variability hypothesis (CVH). Reciprocal acclimation was conducted under spring temperature regimes of both localities, incorporating local diurnal variation. Metabolic rates were measured by closed respirometry, and thermal tolerance limits estimated through thermography. In line with MCA, the higher-latitude population (colder climate) showed higher metabolic rates and temperature coefficients (Q10s) at lower temperatures than the lower-latitude population. As predicted by the CVH, the lower-latitude population (more variable climate) showed higher upper thermal tolerance but only the higher-latitude population was able to acclimate upper thermal limits. This result suggests trade-offs between physiological thermal limits and thermal plasticity in this species. A limited acclimation capacity could make populations on Mediterranean coasts especially vulnerable in the face of projected increases in extreme temperatures under ongoing climate change.

Mejora de la profilaxis antibiótica en cirugía colo-rectal mediante el análisis de las infecciones incisionales: estudio observacional / Improving antibiotic prophylaxis in colorectal surgery through the analysis of incisional infections: observational study

INTRODUCCIÓN. Las infecciones del sitio quirúrgico son muy frecuentes tras cirugía colo-rectal. El objetivo de este estudio es analizar cuantitativa y cualitativamente dichas infecciones en nuestro servicio. MATERIAL Y MÉTODOS. Se realizó un estudio observacional en 23 enfermos sometidos a resecciones colo-rectales programadas a los que se administró la profilaxis antibiótica habitual de nuestro servicio, gentamicina y metronidazol (G+M). Se analizó la presencia de infecciones incisionales superficiales o profundas y los gérmenes causantes. Ante los resultados, y guiados por los cultivos, se decidió cambiar la profilaxis por amoxicilina y ácido clavulánico (AMC), y continuar el estudio en 38 enfermos. RESULTADOS. Los enfermos que recibieron como profilaxis G+M tuvieron un índice de infecciones incisionales del 48%. En el 90% de esas infecciones había Escherichia coli, y en un 80% enterococos o estreptococos. En el grupo de AMC hubo un índice de infecciones incisionales del 19%, siendo la diferencia con el grupo de G+M estadísticamente significativa (p=0,021). En los cultivos de sus heridas no había enterococos ni estreptococos. DISCUSIÓN. El índice de infecciones incisionales del grupo G+M es superior al comunicado en cirugía colo-rectal programada. El predominio de Escherichia coli en estas infecciones es habitual, no así la elevada presencia de cocos positivos, especialmente enterococos. Estos resultados exigen un cambio en nuestra profilaxis antibiótica, para cubrir estreptococos y enterococos, además de bacilos negativos y anaerobios. AMC parece la opción más lógica. Nuestros resultados corroboran esta hipótesis (AU)

BACKGROUND. Surgical site infections are very common after colorectal surgery. The objective of this study is to analyze quantitatively and qualitatively such infections in our service. METHOD. An observational study was performed in 23 patients undergoing elective colorectal resections who received the usual antibiotic prophylaxis of our service, gentamicin and metronidazole (G+M). Superficial and deep incisional infections, as well as microbes that cause them, were analyzed. Given the results, and guided by the cultures, it was decided to change the prophylaxis to amoxicillin and clavulanic acid (AMC), and continue the study in 38 patients. RESULTS. Patients who were given G+M for prophylaxis had incisional infection rate of 48%. Escherichia coli was present in 90% of these infections, enterococci or streptococci were present in 80% of these infections. In the AMC group there was an incisional infection rate of 19%. The observed difference with the G+M group is statistically significant (p = 0.021). Enterococci and streptococci were not isolated in their incisions. CONCLUSION. The rate of incisional infections in the G+M group is higher than the usually reported in elective colorectal surgery. The predominance of Escherichia coli is usual in these infections, but not the high presence of positive cocci, especially enterococci. These results call for a change in our antibiotic prophylaxis to cover streptococci and enterococci, as well as gram-negative bacilli and anaerobes. AMC seems the most logical choice. Our results support this hypothesis (AU)

The role of the neurotransmitters acetylcholine and noradrenaline in the pathogenesis of stress ulcers.

1. Adrenergic and cholinergic mechanisms seem to be involved in the pathogenesis of stress ulcers. 2. In this study, gastric ulcers were induced in rats by immobilization and cold. Prior intraperitoneal administration of both anticholinergic (atropine) as well as alpha-blocking medication (phenoxybenzamine) produced a very significant decrease in stress ulcers. 3. Additionally, using the technique of continuous intravenous perfusion in rats, acetylcholine was shown to have a gastric ulcerogenic effect, in contrast to noradrenaline. 4. It is concluded that acetylcholine is the peripheral mediator in stress ulcers, while noradrenaline intervenes at the encephalic level in stress ulcer pathogenesis.