Correlation between regional tissue perfusion saturation and lactate level during cardiopulmonary bypass.

BACKGROUND: Cardiopulmonary bypass (CPB) can cause systemic hypoperfusion, which remains undetected by routine monitoring of physiological parameters. Noninvasive tissue perfusion monitoring offers a clinical benefit by detecting low systemic perfusion. In this study, we tried to evaluate whether regional tissue perfusion saturation reflects systemic hypoperfusion during CPB. METHODS: This retrospective study included 29 patients with American Society of Anesthesiologists physical status II-III, who required cardiac surgery with CPB. We evaluated the correlations of serum lactate and delivery oxygen with organ perfusion values of peripheral tissue oxygen saturation and cerebral oxygen saturation. Data were recorded at different stages of CPB: T1 (pre-CPB), T2 (cooling), T3 (hypothermia), T4 (rewarming), and T5 (post-CPB). RESULTS: Lactate levels were elevated after CPB and up to weaning (P < 0.05). The levels of peripheral and tissue oxygen saturation decreased after the start of CPB (P < 0.05). Lactate levels were negatively correlated with peripheral tissue oxygen saturation levels at T4 (R = -0.384) and T5 (R = -0.370) and positively correlated with cerebral oxygen saturation at T3 (R = 0.445). Additionally, delivery oxygen was positively correlated with peripheral tissue oxygen saturation at T4 (R = 0.466). CONCLUSIONS: In this study, we demonstrated that peripheral tissue oxygen saturation can be a reliable tool for monitoring systemic hypoperfusion during CPB period. We also believe that peripheral tissue oxygen saturation is a valuable marker for detecting early stages of hypoperfusion during cardiac surgery.

The Effects of Lactobacillus rhamnosus on the Prevention of Asthma in a Murine Model.

PURPOSE: Lactobacilli are probiotic bacteria that are effective in the management of allergic diseases or gastroenteritis. It is hypothesized that such probiotics have immunoregulatory properties and promote mucosal tolerance. Our goal was to investigate whether Lactobacillus casei rhamnosus Lcr35 could inhibit airway inflammation in an ovalbumin (OVA)-induced murine model of asthma. METHODS: BALB/c mice aged 6 weeks were used in the present study. Lactobacillus casei rhamnosus Lcr35 was administered daily, starting 1 week prior to the first OVA sensitization (group 1) and 2 days before the first 1% OVA airway challenge (group 2). Mice that received only saline at both sensitization and airway challenge time points were used as negative controls (group 3), and those that had OVA-induced asthma were used as positive controls (group 4). Airway responsiveness to methacholine was assessed, and bronchoalveolar lavage (BAL) was performed. At the endpoint of the study, total IgE as well as OVA-specific IgE, IgG(1) and IgG(2a) in serum was measured by enzyme-linked immunosorbent assay. Lung pathology was also evaluated. RESULTS: Airway hyperresponsiveness, total cell counts and the proportion of eosinophils in BAL fluid were significantly decreased in group 1 compared with group 4 (P<0.05). Total serum IgE levels were also significantly decreased in group 1 compared with group 4. Serum levels of OVA-specific IgE, IgG(1) and IgG(2a) were not significantly influenced by treatment with Lcr35. There was significantly less peribronchial and perivascular infiltration of inflammatory cells in group 1 compared with group 4; however, there were no significant differences in methacholine challenge, BAL, serology or histology between groups 2 and 4. CONCLUSIONS: Oral treatment with Lcr35 prior to sensitization can attenuate airway inflammation and hyperreactivity in a mouse model of allergic airway inflammation. These results suggest that Lcr35 may have potential for preventing asthma.

Enteral administration of a synthetic monoacetyldiglyceride improves survival in a murine model of abdominal sepsis.

BACKGROUND: A monoacetyldiglyceride (MADG) markedly improves survival in a murine model of abdominal sepsis. MADGs have been shown to stimulate hematopoiesis in vitro. We examined effects of MADG administration in setting of cecal ligation and puncture (CLP) and hypothesized that oral (p.o.) administration of MADG would result in alterations of cytokine and chemokine expression after CLP. METHODS: Four groups of 20 mice: sham group underwent celiotomy but not CLP; control group underwent CLP and administration of phosphate buffer solution; simultaneous treatment group had administration of 50 mg/kg MADG p.o. Immediately, before CLP and at 24, 48, and 72-hour post-CLP, posttreatment group had initial administration of MADG at 1-hour post-CLP, and at 24, 48, and 72-hour postoperative. We followed survival to 10-day postoperative. Serum and tissue levels of pro- and anti-inflammatory cytokines were measured. Serum levels of chemokines stromal cell-derived factor (SDF-1) and stem cell factor (SCF) were measured to ascertain if effects of MADG involve stimulation of bone marrow stromal and stem cells. Polymerase chain reaction was used to measure SDF and SCF mRNA expression in liver and lung. RESULTS: Administration of MADG (p.o.) significantly improved survival in mice after CLP with associated systemic alterations of a variety of cytokines. Increased levels of mRNA coding for SCF and SDF in lung and liver were found after CLP. CONCLUSIONS: Administration of MADG (p.o.) after CLP results in marked improvement in survival. Cytokine level changes demonstrate associated immunomodulatory effects. These effects may be mediated by bone marrow stromal and stem cell activation, evidenced by increases in SDF and SCF. Further study of behavior of bone marrow-derived stem cells in setting of sepsis is warranted. MADG may hold promise for use in treatment of sepsis.

Pace of macrophage recruitment during different stages of soft tissue infection: semi-quantitative evaluation by in vivo magnetic resonance imaging.

We describe the pace of recruitment of iron-oxide-labeled macrophages to the site of different stages of infection by in vivo magnetic resonance (MR) imaging. Peritoneal macrophages were labeled with superparamagnetic iron oxide ex vivo and administered through the tail vein 6 (acute) or 48 (subacute) h after bacterial inoculation. The legs of the mice were imaged sequentially on a 4.7-T MR unit before and 3, 6, 12, 18, 24, 48 and 72 h after macrophage administration. The band-shaped lower signal intensity zone around the abscess on T2*-weighted GRE images became more obvious due to recruited macrophages up until 24 h after injection in the subacute and 48 h after injection in the acute group, indicating that the relative SI of the abscess wall decreased more rapidly and the pace of recruitment of macrophages was faster in the subacute than in the acute group. Chemokine antibody arrays of mouse sera detected increased concentration of granulocyte-colony-stimulating factor and tissue inhibitor of metalloproteinase-1 beginning at 12 h and increased interleukin-13 at 18 h. Monocyte chemoattractant protein-1 and macrophage-colony-stimulating factor began to increase at 96 h after infection. This difference in pace of recruitment may result from the release of chemokines.