Outcomes of patients with acute respiratory failure after abdominal surgery treated with noninvasive positive pressure ventilation

OBJECTIVES: Little is known about the physiologic and clinical effects of noninvasive positive pressure ventilation (NPPV) in patients who have acute respiratory failure (ARF) after abdominal surgery. We evaluated our clinical experience with the use of NPPV in the treatment of ARF after abdominal surgery. METHODS: We prospectively evaluated NPPV use during a 2-year period in a medical-surgical ICU of a university hospital. We documented demographic and diagnostic data, gas exchange, and clinical outcomes. We compared patients who were not intubated to those who were intubated after a trial of NPPV. RESULTS: Of 72 patients with ARF after abdominal surgery who were treated with NPPV, 48 patients avoided intubation (67%). Patients in the intubated and nonintubated groups had similar demographic characteristics, and similar American Society of Anesthesiologists physical status and simplified acute physiology score II scores at admission. The intubated group had a significantly lower Pa(O2)/fraction of inspired oxygen (Fi(O2)) ratio (123 +/- 62 mm Hg vs 194 +/- 76 mm Hg, p < 0.01) and more extended bilateral alveolar infiltrates (67% vs 31%, p < 0.01) than the non-intubated group. Within the first NPPV observation period, the Pa(O2)/Fi(O2) increased (+ 36 +/- 29% [+/- SD], p = 0.04) and the respiratory rate decreased (28.2 +/- 3.4 breaths/min vs 23.1 +/- 3.8 breaths/min, p < 0.01) significantly only in the non-intubated group. The non-intubated group had significantly lower length of ICU stay (17.3 +/- 10.9 days vs 34.1 +/- 28.5 days, p < 0.01) and mortality rate (6% vs 29%, p < 0.01). CONCLUSION: NPPV may be an alternative to conventional ventilation in selected patients with ARF after abdominal surgery who require ventilatory support.     

Telaprevir- and boceprevir-based tritherapies in real practice for F3-F4 pretreated hepatitis C virus patients

AIM:To assess,in a routine practice setting,the sus-tained virologic response(SVR) to telaprevir(TPV) or boceprevir(BOC) in hepatitis C virus(HCV) nullresponders or relapsers with severe liver fibrosis.METHODS:One hundred twenty-five patients were treated prospectively for 48 wk with TPV or BOC + pegylated-interferon(peg-INF) α2a + ribavirin(PR) according to standard treatment schedules without randomization.These patients were treated in routine practice settings in 10 public or private health care centers,and the data were prospectively collected.Only patients with severe liver fibrosis(Metavir scores of F3 or F4 upon liver biopsy or liver stiffness assessed by elastography),genotype 1 HCV and who were null-responders or relapsers to prior PR combination therapy were included in this study.RESULTS:The Metavir fibrosis scores were F3 in 35(28%) and F4 in 90(72%) of the patients.In total,62.9% of the patients were null-responders and 37.1% relapsers to the previous PR therapy.The overall SVR rate at 24 wk post-treatment withdrawal was 59.8%.The SVR was 65.9% in the TPV group and 44.1% in the BOC group.Independent predictive factors of an SVR included a response to previous treatment,relapsers vs null-responders [OR = 3.9;(1.4,10.6),P = 0.0084],a rapid virological response(RVR) [OR 6.9(2.6,18.2),P = 0.001] and liver stiffness lower than 21.3 kPa [OR = 8.2(2.3,29.5),P = 0.001].During treatment,63 patients(50.8%) had at least one severe adverse event(SAE) of grade 3 or 4.A multivariate analysis identified two factors associated with SAEs:female gender [OR = 2.4(1.1,5.6),P = 0.037] and a platelet count below 150 × 103/ mm3 [OR = 5.3(2.3,12.4),P ≤ 0.001].CONCLUSION:More than half of these difficult-to-treat patients achieved an SVR and had SAEs in an actual practice setting.The SVR rate was influenced by the response to previous PR treatment,the RVR and liver stiffness.     

Effects of temperature on urinary corticosterone metabolite responses to short-term capture and handling stress in the cane toad (Rhinella marina)

Extreme temperature can cause metabolic, immune and behavioural changes in amphibians. Short-term stress hormonal response via increased secretion of corticosterone enables amphibians to make necessary physiological and behavioural adjustments for coping with stressors. The effect of temperature on short-term corticosterone responses has not been studied in amphibians. In this study, this relationship was evaluated in adult male cane toads (Rhinella marina). We acclimated male toads (n=24 toads per group) at low, medium and high temperature (15, 25 or 35°C) under controlled laboratory conditions for a 14day period. After thermal acclimation, short-term corticosterone responses were evaluated in the toads subjected to a standard capture and handling stress protocol over a 24h period. Corticosterone metabolites in toad urine were measured via enzyme-immunoassay. During acclimation, mean baseline urinary corticosterone level increased after transfer of the toads from wild into captivity and returned to baseline on day 14 of acclimation for each of the three temperatures. At the end of the 14days of thermal acclimation period, baseline corticosterone level were highest for toad group at 35°C and lowest at 15°C. All toads generated urinary corticosterone responses to the standard capture and handling stressor for each temperature. Both individual and mean short-term corticosterone responses of the toads were highest at 35°C and lowest at 15°C. Furthermore, Q(10) values (the factor by which the reaction rate increases when the temperature is raised by 10°) were calculated for mean corrected integrated corticosterone responses as follows; (15-35°C) Q(10)=1.51, (15-25°C) Q(10)=1.60; (25-35°C) Q(10)=1.43. Both total and corrected integrated corticosterone responses were highest for toads at 35°C followed by 25°C and lowest for the 15°C toad group. Overall, the results have demonstrated the thermodynamic response of corticosterone secretion to short-term capture and handling stress in an amphibian species.     

Individual variation and repeatability in urinary corticosterone metabolite responses to capture in the cane toad (Rhinella marina)

Urinary corticosterone metabolite enzyme-immunoassay (EIA) can be used for the non-invasive assessment of baseline levels and corticosterone responses in amphibians. In this study, urinary corticosterone responses of wild male cane toads (Rhinella marina) to confinement and repeated handling were measured to quantify individual variation in corticosterone responses for the first time in an amphibian species. Urine samples were collected at 0 h in the wild, hourly from 2 to 8 h after transfer into captivity, and again at 12 and 24 h in captivity. Toads were then held in captivity and subjected to the same sampling protocol on three occasions at 14 days intervals to quantify variation in corticosterone metabolite responses within and between toads. Baseline and individual corticosterone metabolite responses in male cane toads were generally consistent, with high statistical repeatabilities for 0 h (r=0.630), 6 h (r=0.793), 12 h (r=0.652) and 24 h (r=0.721) corticosterone metabolite concentrations, and for the total and corrected integrated corticosterone responses (r=0.567, p=0.033; r=0.728, p=0.014 respectively). Urinary corticosterone responses appear to be a stable, repeatable trait within individuals. Corticosterone responses in amphibians can be more readily measured when urine rather than plasma samples are collected, and the protocol established in the current study can now be applied to the study of variation in corticosterone responses in other amphibians.     

Bacterial expression of mutant argininosuccinate lyase reveals imperfect correlation of in-vitro enzyme activity with clinical phenotype in argininosuccinic aciduria

Background

The urea cycle defect argininosuccinate lyase (ASL) deficiency has a large spectrum of presentations from highly severe to asymptomatic. Enzyme activity assays in red blood cells or fibroblasts, although diagnostic of the deficiency, fail to discriminate between severe, mild or asymptomatic cases. Mutation/phenotype correlation studies are needed to characterize the effects of individual mutations on the activity of the enzyme.

Methods

Bacterial in-vitro expression studies allowed the enzyme analysis of purified mutant ASL proteins p.I100T (c.299?T?>?C), p.V178M (c.532?G?>?A), p.E189G (c.566A?>?G), p.Q286R (c.857A?>?G), p.K315E (c.943A?>?G), p.R379C (c.1135?C?>?T) and p.R385C (c.1153?C?>?T) in comparison to the wildtype protein.

Results

In the bacterial in-vitro expression system, ASL wild-type protein was successfully expressed. The known classical p.Q286R, the novel classical p.K315E and the known mutations p.I100T, p.E189G and p.R385C, which all have been linked to a mild phenotype, showed no significant residual activity. There was some enzyme activity detected with the p.V178M (5 % of wild-type) and p.R379C (10 % of wild-type) mutations in which K_m values for argininosuccinic acid differed significantly from the wild-type ASL protein.

Conclusion

The bacterially expressed enzymes proved that the mutations found in patients and studied here indeed are detrimental. However, as in the case of red cell ASL activity assays, some mutations found in genetically homozygous patients with mild presentations resulted in virtual loss of enzyme activity in the bacterial system, suggesting a more protective environment for the mutant enzyme in the liver than in the heterologous expression system and/or in the highly dilute assays utilized here.     

Effects of aging and menopause on serum interleukin-6 levels and peripheral blood mononuclear cell cytokine production in healthy nonobese women

Inappropriate interleukin-6 production is thought to play a role in the development of several age-related conditions including atherosclerosis. This study aimed to determine whether aging affects circulating interleukin-6 (IL-6) levels. Healthy, nonobese women (n = 208, 44.5 ± 0.70 years, 22.4 ± 0.17 kg/m²) were categorized into four age groups (22–31, 32–41, 42–51, and 52–63 years; cross-sectional study). Cytokine levels in serum and those produced from peripheral blood mononuclear cell (PBMC) were measured. The oldest group had the highest circulating levels of IL-6 and oxidized low-density lipoprotein (ox-LDL) and higher PBMC production of IL-6, tumor necrosis factor-α (TNF-α), and interleukin-1 alpha (IL-1β). Additionally, significant interactions between age and menopause were found for serum IL-6 (P = 0.024), and TNF-α (P = 0.011) and IL-1β (P < 0.001) produced from PBMCs. Serum IL-6 levels positively correlated with age, waist–hip ratio (WHR), systolic blood pressure, circulating levels of TNF-α, IL-1β, and ox-LDL, and urinary 8-epi-prostaglandin F₂α. Multiple stepwise regression models identified the following factors for contributing to serum IL-6 levels: serum IL-1β, menopause status, WHR, and serum TNF-α in mode I (R ² = 0.302); serum IL-1β, age, serum TNF-α, and WHR (β = 0.197; P = 0.006) in model II (R ² = 0.283). Sub-analysis was performed according to menopausal status. Serum IL-6 levels were positively associated with levels of IL-6, TNF-α, and IL-1β in PBMC supernatants (unstimulated) from postmenopausal women, whereas these were negatively associated in premenopausal women. In conclusion, circulating IL-6 levels may be interactively influenced by age and menopause. Additionally, estrogen deprivation after menopause may enhance PBMC cytokine production in postmenopausal women, resulting in increased IL-6 levels which are closely related to oxidative stress.     

Comparison of pro-atrial natriuretic peptide and atrial remodeling in marathon versus non-marathon runners

Long-term endurance sports are associated with atrial remodeling and an increased risk for atrial fibrillation (AF) and atrial flutter. Pro-atrial natriuretic peptide (pro-ANP) is a marker of atrial wall tension and elevated in patients with AF. The aim of this study was to test the hypothesis that atrial remodeling would be perpetuated by repetitive episodes of atrial stretching during strenuous competitions, reflected by elevated levels of pro-ANP. A cross-sectional study was performed on nonelite runners scheduled to participate in the 2010 Grand Prix of Bern, a 10-mile race. Four hundred ninety-two marathon and nonmarathon runners applied for participation, 70 were randomly selected, and 56 entered the final analysis. Subjects were stratified according to former marathon participations: a control group (nonmarathon runners, n = 22), group 1 (1 to 4 marathons, n = 16), and group 2 (≥5 marathons, n = 18). Results were adjusted for age, training years, and average weekly endurance training hours. The mean age was 42 ± 7 years. Compared to the control group, marathon runners in groups 1 and 2 had larger left atria (25 ± 6 vs 30 ± 6 vs 34 ± 7 ml/m(2), p = 0.002) and larger right atria (27 ± 7 vs 31 ± 8 vs 35 ± 5 ml/m(2), p = 0.024). Pro-ANP levels at baseline were higher in marathon runners (1.04 ± 0.38 vs 1.42 ± 0.74 vs 1.67 ± 0.69 nmol/L, p = 0.006). Pro-ANP increased significantly in all groups after the race. In multiple linear regression analysis, marathon participation was an independent predictor of left atrial (β = 0.427, p <0.001) and right atrial (β = 0.395, p = 0.006) remodeling. In conclusion, marathon running was associated with progressive left and right atrial remodeling, possibly induced by repetitive episodes of atrial stretching. The altered left and right atrial substrate may facilitate atrial arrhythmias.