Effect of Elevated Intra-Abdominal Pressure on Portal Vein and Superior Mesenteric Artery Blood Flow in a Rat

Abstract Aim: Recent clinical experience suggests that minimal access portoenterostomy (the Kasai procedure) for biliary atresia leads to transplantation sooner, compared to the traditional open approach. It should be emphasized that elevated intra-abdominal pressure (IAP) may reduce hepatic and portal blood flow and thus may cause histologic liver damage. The aim of the present study was to evaluate the effects of IAP on blood flow in the portal vein (PV), compared to the superior mesenteric artery (SMA), and on the systemic mean arterial blood pressure (MABP). Materials and Methods: Male Sprague-Dawley rats were anesthetized with intraperitoneal ketamine (90 mg per kg) and xylasine (13 mg per kg). Polyethylene catheters (PE-50) were introduced into the right carotid artery for the measurement of MABP. After a midline laparotomy, the SMA and PV were isolated. Ultrasonic blood-flow probes were placed on the vessels for the continuous measurement of regional blood flow. Two large-caliber percutaneous peripheral intravenous catheters were introduced into the peritoneal cavity for inflation of air and for the measurement of IAP. The time course of MABP and SMA and PV flow as well as the relationship between IAP and SMA and PV flow were determined. Results: Although all three hemodynamic parameters decreased with the increase in the IAP, the most significant changes were observed in PV blood flow. IAP at 3 mm Hg resulted in a 26% decrease in PV flow (P < 0.05), a 19% decrease in SMA flow (P < 0.05), and an 11% decrease in MABP (P < 0.05). IAP at 6 mm Hg caused a two-fold decrease in PV flow (P < 0.05), a 30% decrease in SMA flow (P < 0.05), and a 19% decrease in MABP (P < 0.05). There were no changes in the time course of MABP and PV and SMA flow. PV and SMA flow returned to normal values immediately after abdominal deflation. Conclusions: Persistent IAP decreased MABP, SMA, and, especially, PV flow by 50%. We speculate that in biliary atresia patients with already present liver dysfunction, decrease in SMA flow and even a greater decrease in PV flow from increased IAP, which occurs during a laparoscopic Kasai procedure, may further compromise liver function. This may be one of the explanations for the progression to earlier transplantation in infants undergoing a laparoscopic Kasai procedure.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78156/1/lap.2008.0145.supp.pd

The risk stratification of adverse neonatal outcomes in women with gestational diabetes (STRONG) study

Aims: To assess the risk of adverse neonatal outcomes in women with gestational diabetes (GDM) by identifying subgroups of women at higher risk to recognize the characteristics most associated with an excess of risk. Methods: Observational, retrospective, multicenter study involving consecutive women with GDM. To identify distinct and homogeneous subgroups of women at a higher risk, the RECursive Partitioning and AMalgamation (RECPAM) method was used. Overall, 2736 pregnancies complicated by GDM were analyzed. The main outcome measure was the occurrence of adverse neonatal outcomes in pregnancies complicated by GDM. Results: Among study participants (median age 36.8 years, pre-gestational BMI 24.8 kg/m2), six miscarriages, one neonatal death, but no maternal death was recorded. The occurrence of the cumulative adverse outcome (OR 2.48, 95% CI 1.59–3.87), large for gestational age (OR 3.99, 95% CI 2.40–6.63), fetal malformation (OR 2.66, 95% CI 1.00–7.18), and respiratory distress (OR 4.33, 95% CI 1.33–14.12) was associated with previous macrosomia. Large for gestational age was also associated with obesity (OR 1.46, 95% CI 1.00–2.15). Small for gestational age was associated with first trimester glucose levels (OR 1.96, 95% CI 1.04–3.69). Neonatal hypoglycemia was associated with overweight (OR 1.52, 95% CI 1.02–2.27) and obesity (OR 1.62, 95% CI 1.04–2.51). The RECPAM analysis identified high-risk subgroups mainly characterized by high pre-pregnancy BMI (OR 1.68, 95% CI 1.21–2.33 for obese; OR 1.38 95% CI 1.03–1.87 for overweight). Conclusions: A deep investigation on the factors associated with adverse neonatal outcomes requires a risk stratification. In particular, great attention must be paid to the prevention and treatment of obesity

The Effect of p38 Mitogen-Activated Protein Kinase Activation on Inflammatory Liver Damage following Hemorrhagic Shock in Rats

Hemorrhagic shock is a frequent cause of liver failure and often leads to a fatal outcome. Several studies have revealed that p38 MAPK is a key mediator in hemorrhagic damage of the primary organs through the activation of proinflammatory cytokines such as tumor necrosis factor (TNF)-α and interleukin (IL)-1β. However, the precise role of these factors in liver damage following hemorrhagic shock is unclear. In this study, we used FR167653, a specific inhibitor of p38 MAPK phosphorylation, to examine the role of p38 MAPK in liver damage occurring up to 5 hours after a hemorrhagic episode in a rat model. Activation of p38 MAPK in the liver as well as an increase in hepatic mRNA expression and serum concentrations of TNF-α and IL-1β occurred during the early phase after hemorrhage. Increased serum levels of hepatic enzymes, as well as histological damage and activated neutrophil accumulation in the liver, were observed in the late phase following hemorrhagic shock. FR167653 inhibited the inflammation-related hepatic injury following hemorrhagic shock. Bacterial lipopolysaccharide (LPS) derived from the gut appeared to have little effects on the hepatic damage. These results demonstrate that p38 MAPK activation is induced by hepatic ischemia during hemorrhagic shock and plays an important role both in the hepatic expression of proinflammatory cytokines and in the development of inflammation-related liver damage

Lateralization in the Invertebrate Brain: Left-Right Asymmetry of Olfaction in Bumble Bee, Bombus terrestris

Brain and behavioural lateralization at the population level has been recently hypothesized to have evolved under social selective pressures as a strategy to optimize coordination among asymmetrical individuals. Evidence for this hypothesis have been collected in Hymenoptera: eusocial honey bees showed olfactory lateralization at the population level, whereas solitary mason bees only showed individual-level olfactory lateralization. Here we investigated lateralization of odour detection and learning in the bumble bee, Bombus terrestris L., an annual eusocial species of Hymenoptera. By training bumble bees on the proboscis extension reflex paradigm with only one antenna in use, we provided the very first evidence of asymmetrical performance favouring the right antenna in responding to learned odours in this species. Electroantennographic responses did not reveal significant antennal asymmetries in odour detection, whereas morphological counting of olfactory sensilla showed a predominance in the number of olfactory sensilla trichodea type A in the right antenna. The occurrence of a population level asymmetry in olfactory learning of bumble bee provides new information on the relationship between social behaviour and the evolution of population-level asymmetries in animals

Population pharmacokinetics of colistin and the relation to survival in critically ill patients infected with colistin susceptible and carbapenem-resistant bacteria

Objectives: The aim was to analyse the population pharmacokinetics of colistin and to explore the relationship between colistin exposure and time to death. Methods: Patients included in the AIDA randomized controlled trial were treated with colistin for severe infections caused by carbapenem-resistant Gram-negative bacteria. All subjects received a 9 million units (MU) loading dose, followed by a 4.5 MU twice daily maintenance dose, with dose reduction if creatinine clearance (CrCL) 2 mg/L in 94% (195/208) and 44% (38/87) of patients with CrCL ≤120 mL/min, and >120 mL/min, respectively. Colistin methanesulfonate sodium (CMS) and colistin clearances were strongly dependent on CrCL. High colistin exposure to MIC ratio was associated with increased hazard of death in the multivariate analysis (adjusted hazard ratio (95% CI): 1.07 (1.03–1.12)). Other significant predictors included SOFA score at baseline (HR 1.24 (1.19–1.30) per score increase), age and Acinetobacter or Pseudomonas as index pathogen. Discussion: The population pharmacokinetic model predicted that >90% of the patients had colistin concentrations

Pyrethroids and Nectar Toxins Have Subtle Effects on the Motor Function, Grooming and Wing Fanning Behaviour of Honeybees (Apis mellifera)

Sodium channels, found ubiquitously in animal muscle cells and neurons, are one of the main target sites of many naturally-occurring, insecticidal plant compounds and agricultural pesticides. Pyrethroids, derived from compounds found only in the Asteraceae, are particularly toxic to insects and have been successfully used as pesticides including on flowering crops that are visited by pollinators. Pyrethrins, from which they were derived, occur naturally in the nectar of some flowering plant species. We know relatively little about how such compounds—i.e., compounds that target sodium channels—influence pollinators at low or sub-lethal doses. Here, we exposed individual adult forager honeybees to several compounds that bind to sodium channels to identify whether these compounds affect motor function. Using an assay previously developed to identify the effect of drugs and toxins on individual bees, we investigated how acute exposure to 10 ng doses (1 ppm) of the pyrethroid insecticides (cyfluthrin, tau-fluvalinate, allethrin and permethrin) and the nectar toxins (aconitine and grayanotoxin I) affected honeybee locomotion, grooming and wing fanning behaviour. Bees exposed to these compounds spent more time upside down and fanning their wings. They also had longer bouts of standing still. Bees exposed to the nectar toxin, aconitine, and the pyrethroid, allethrin, also spent less time grooming their antennae. We also found that the concentration of the nectar toxin, grayanotoxin I (GTX), fed to bees affected the time spent upside down (i.e., failure to perform the righting reflex). Our data show that low doses of pyrethroids and other nectar toxins that target sodium channels mainly influence motor function through their effect on the righting reflex of adult worker honeybees