Effects of Caloric Restriction on Spatial Object Recognition Memory, Hippocampal Neuron Loss and Neuroinflammation in Aged Rats.

Age-related neurobiological changes significantly affect hippocampal structure and function, such that the main cognitive impairments associated with aging are related to the integrity of this brain structure, including the deterioration in spatial object recognition (SOR) memory. Previous studies have shown that intrinsic factors such as neuroinflammation, as well as lifestyle factors such as diet, can affect aging-associated brain functions and cognitive performance. In this regard, caloric restriction (CR) produces beneficial effects on health and life expectancy, although its ability to slow down age-dependent effects on cognitive decline and hippocampus (HPC) functioning remains unclear. Therefore, we set out to evaluate the effects of CR on SOR memory in aged male Wistar rats, as well as those on hippocampal neuron loss, neurogenesis and inflammation. The data show that CR in aged rats attenuates the decline in SOR memory, age-associated hippocampal neuron loss, and age-dependent microglial activation. Furthermore, we found a significant reduction in neurogenesis in the dentate gyrus of the old animals relative to adult rats. These findings support the positive effect of CR on SOR memory, suggesting that it dampens hippocampal neuronal loss and reduces proinflammatory activity.

Longitudinal Changes in Patient-Ventilator Asynchronies and Respiratory System Mechanics Before and After Tracheostomy.

BACKGROUND: This was a pilot study to analyze the effects of tracheostomy on patient-ventilator asynchronies and respiratory system mechanics. Data were extracted from an ongoing prospective, real-world database that stores continuous output from ventilators and bedside monitors. Twenty adult subjects were on mechanical ventilation and were tracheostomized during an ICU stay: 55% were admitted to the ICU for respiratory failure and 35% for neurologic conditions; the median duration of mechanical ventilation before tracheostomy was 12 d; and the median duration of mechanical ventilation was 16 d. METHODS: We compared patient-ventilator asynchronies (the overall asynchrony index and the rates of specific asynchronies) and respiratory system mechanics (respiratory-system compliance and airway resistance) during the 24 h before tracheostomy versus the 24 h after tracheostomy. We analyzed possible differences in these variables among the subjects who underwent surgical versus percutaneous tracheostomy. To compare longitudinal changes in the variables, we used linear mixed-effects models for repeated measures along time in different observation periods. A total of 920 h of mechanical ventilation were analyzed. RESULTS: Respiratory mechanics and asynchronies did not differ significantly between the 24-h periods before and after tracheostomy: compliance of the respiratory system median (IQR) (47.9 [41.3 - 54.6] mL/cm H2O vs 47.6 [40.9 - 54.3] mL/cm H2O; P = .94), airway resistance (9.3 [7.5 - 11.1] cm H2O/L/s vs 7.0 [5.2 - 8.8] cm H2O/L/s; P = .07), asynchrony index (2.0% [1.1 - 3.6%] vs 4.1% [2.3 - 7.6%]; P = .09), ineffective expiratory efforts (0.9% [0.4 - 1.8%] vs 2.2% [1.0 - 4.4%]; P = .08), double cycling (0.5% [0.3 - 1.0%] vs 0.9% [0.5 - 1.9%]; P = .24), and percentage of air trapping (7.6% [4.2 - 13.8%] vs 10.6% [5.9 - 19.2%]; P = .43). No differences in respiratory mechanics or patient-ventilator asynchronies were observed between percutaneous and surgical procedures. CONCLUSIONS: Tracheostomy did not affect patient-ventilator asynchronies or respiratory mechanics within 24 h before and after the procedure.

Reactivity of pure Candida rugosa lipase isoenzymes (Lip1, Lip2, and Lip3) in aqueous and organic media. influence of the isoenzymatic profile on the lipase performance in organic media.

Three pure isoenzymes from Candida rugosa lipase (CRL: Lip1, Lip2, and Lip3) were compared in terms of their stability and reactivity in both aqueous and organic media. The combined effect of temperature and pH on their stability was studied applying a factorial design. The analysis of the response surfaces indicated that Lip1 and Lip3 have a similar stability, lower than that of Lip2. In aqueous media, Lip3 was the most active enzyme on the hydrolysis of p-nitrophenyl esters, whereas Lip1 showed the highest activity on the hydrolysis of most assayed triacylglycerides. The highest differences among isoenzymes were found in the hydrolysis of triacylglycerides. Thus, a short, medium, and long acyl chain triacylglyceride was the preferred substrate for Lip3, Lip1, and Lip2, respectively. In organic medium, Lip3 and Lip1 provided excellent results in terms of enantioselectivity in the resolution of ibuprofen (EF value over 0.90) and conversion, whereas initial esterification rate was higher for Lip3. However, the use of Lip2 resulted in lower values of conversion, enantiomeric excess, and enantioselectivity. In the case of trans-2-phenyl-1-cyclohexanol (TPCH) resolution, initial esterification rates were high except for Lip3, which also produced poor results in conversion and enantiomeric excess. The performance of the pure isoenzymes in the enantioselectivity esterification of these substrates was compared with different CRL crude preparations with known isoenzymatic content and the different results could not be explained by their isoenzymatic profile. Therefore, it can be concluded that other factors can also affect the catalysis of CRL and only the reproducibility between powders can ensure the reproducibility in synthesis reactions.