[Regional cerebral oxygen saturation as a marker of hemodynamic state following cardiac surgery]. / Saturación cerebral de oxígeno como marcador hemodinámico en la cirugía cardíaca.

INTRODUCTION: Regional cerebral oxygen saturation (rSO2) is a measure of the general state of perfusion and oxygenation. We aim to analyze the relationship between this and various hemodynamic and respiratory parameters. PATIENTS AND METHODS: Forty-three patients, operated on between October 2011 and July 2012, were included in this prospective observational descriptive study. The following parameters were measured: mean arterial pressure, both arterial and central venous oxygen saturation and partial pressures of oxygen and carbon dioxide, and lactate levels. From these parameters, the oxygenation index and the oxygen extraction ratio were calculated. These measurements were studied to evaluate whether rSO2 correlated significantly with the other parameters. RESULTS: The average age and weight of the patients were 27.3 months and 9.2 kg, respectively. The rSO2 correlated positively with both central venous oxygen saturation (r=0.73, P<.01) and mean arterial pressure (r=0.59, P<.01), and negatively with the oxygen extraction ratio (r=-0.7, P<.01). No correlation was found with the respiratory parameters. Concordance analysis established an acceptable Kappa index (> 0.4) between the rSO2 and central venous oxygen saturation, and between the rSO2 and oxygen extraction ratio. CONCLUSIONS: Regional cerebral oxygen saturation correlates well with hemodynamic parameters - mean arterial pressure, venous saturation, and the tissue oxygen extraction. However, it does not correlate with respiratory parameters.

Adiponectin: anti-inflammatory and cardioprotective effects.

Adipose tissue is an endocrine organ that plays an essential role in regulating several metabolic functions through the secretion of biological mediators called "adipokines". Dysregulation of adipokines plays a crucial role in obesity-related diseases. Adiponectin (APN) is the most abundant adipokine accounting for the 0.01% of total serum protein, and is involved in a wide variety of physiological processes including energy metabolism, inflammation, and vascular physiology. APN plasma levels are reduced in individuals with obesity, type 2 diabetes and coronary artery disease, all traits with low-grade chronic inflammation. It is has been suggested that the absence of APN anti-inflammatory effects may be a contributing factor to this inflammation. APN inhibits the expression of tumor necrosis factor-α-induced endothelial adhesion molecules, macrophage-to-foam cell transformation, tumor necrosis factor-α expression in macrophages and adipose tissue, and smooth muscle cell proliferation. It also has anti-apoptotic and anti-oxidant effects, which play a role in its cardioprotective action. This review will focus on APN as an anti-inflammatory, anti-atherogenic and cardioprotective plasma protein.

Caecal and colonic uptake of both linoleic acid and cholesterol in rats following intestinal resection.

Caecal and colonic uptake of both linoleic acid and cholesterol were studied in rats after distal small bowel resection (DSBR). The results showed that the surgical operation increased the caecal and colonic uptake of linoleic acid. Supplementation with linolenic acid inhibited caecal and colonic uptake of linoleic acid. Experiments carried out in the presence of rotenone and ouabain suggest that facilitated diffusion is the predominant mechanism of caecal and colonic linoleic acid absorption, at least at low concentrations. An increase in caecal and colonic uptake of cholesterol was observed after the surgical operation. The study showed that facilitated diffusion seems to be the mechanism of linoleic acid absorption in the caecum and colon, and that both organ growth and changes in transport function of the epithelial cells of caecum and colon appear to be involved in the adaptive response of the bowel to intestinal resection.

Role of rat large intestine in reducing diarrhea after 50% or 80% distal small bowel resection.

The effects of intestinal resection on several intestinal parameters have been studied in the large intestine of rats one month after the surgical operation. The results show that both 50% and 80% distal small bowel resection increased net fluid absorption and mucosal permeability and caused expansion of the intercellular spaces of the large intestine. The increase in net fluid absorption was dependent upon the extent of the intestine removed. The cAMP and cGMP content of cecal and colonic mucosa were significantly reduced after jejunoilectomy. Changes in nucleotide levels were dependent on the length of the intestine resected. On the other hand, mucosa Na,K-ATPase specific activity was only increased in the cecum after 80% intestinal resection. The results are discussed in terms of adaptation to prevent diarrhea.

Distal small bowel resection does not modify the intestinal 3-hydroxy-3-methylglutaryl CoA reductase activity.

The activity of 3-hydroxy-3-methylglutaryl coenzyme-A reductase (HMG-CoA red.) has been evaluated in rat jejunal, caecal and colonic mucosa adapting to 50% or 75% distal small bowel resection (SBR). Six wk after surgery, the total activity and the activity state (active form) of the enzyme were determined. The results show that HMG-CoA red. activity was stimulated per organ but not per unit mass in the mucosa adapting to SBR. As a side result, we noted regional differences in the active/total reductase ratio (RA/RT) for HMG-CoA red. that was lower in small intestine compared with that of the large intestine.

Adaptation of electrolytes and fluid transport in rat small and large intestine after distal small bowel resection.

Na+, Cl- and water transport were studied in jejunum, caecum and colon after either 50% or 80% of small bowel resection (SBR). Four weeks after surgery, dry and wet weights, net absorption in vivo of sodium, chloride and water were determined. There was a significant intestinal growth after 50% or 80% SBR except for the colon which only showed increased tissue mass after 80% SBR. Net transport was stimulated both, per organ and per unit mass. In the small intestine and caecum both organ growth and changes in cell function appear to be involved in the adaptive response, regardless the extent of the small intestine resected. In the colon, compensatory growth appear to contribute to the adaptive response only after 80% SBR, whilst the transport function of the colonocytes seems to be stimulated after both types of SBR.