Trolox and Ascorbic Acid Reduce Direct and Indirect Oxidative Stress in the IPEC-J2 Cells,an In Vitro Model for the Porcine Gastrointestinal Tract

Oxidative stress in the small intestinal epithelium is a major cause of barrier malfunction and failure to regenerate. This study presents a functional in vitro model using the porcine small intestinal epithelial cell line IPEC-J2 to examine the effects of oxidative stress and to estimate the antioxidant and regenerative potential of Trolox, ascorbic acid and glutathione monoethyl ester. Hydrogen peroxide and diethyl maleate affected the tight junction (zona occludens-1) distribution, significantly increased intracellular oxidative stress (CM-H₂DCFDA) and decreased the monolayer integrity (transepithelial electrical resistance and FD-4 permeability), viability (neutral red) and wound healing capacity (scratch assay). Trolox (2 mM) and 1 mM ascorbic acid pre-treatment significantly reduced intracellular oxidative stress, increased wound healing capacity and reduced FD-4 permeability in oxidatively stressed IPEC-J2 cell monolayers. All antioxidant pre-treatments increased transepithelial electrical resistance and viability only in diethyl maleate-treated cells. Glutathione monoethyl ester (10 mM) pre-treatment significantly decreased intracellular oxidative stress and monolayer permeability only in diethyl maleate-treated cells. These data demonstrate that the IPEC-J2 oxidative stress model is a valuable tool to screen antioxidants before validation in piglets.     

Rate of progression of CT-quantified emphysema in male current and ex-smokers: a follow-up study

Background

Little is known about the factors associated with CT-quantified emphysema progression in heavy smokers. The objective of this study was to investigate the effect of length of smoking cessation and clinical / demographical factors on the rate of emphysema progression and FEV₁-decline in male heavy smokers.

Methods

3,670 male smokers with mean (SD) 40.8 (17.9) packyears underwent chest CT scans and pulmonary function tests at baseline and after 1 and 3 years follow-up. Smoking status (quitted ≥5, ≥1-<5, <1 years or current smoker) was noted. Rate of progression of emphysema and FEV₁-decline after follow-up were assessed by analysis of variance adjusting for age, height, baseline pulmonary function and emphysema severity, packyears, years in study and respiratory symptoms. The quitted ≥5 group was used as reference.

Results

Median (Q1-Q3) emphysema severity,<-950 HU, was 8.8 (5.1 – 14.1) and mean (SD) FEV₁ was 3.4 (0.73) L or 98.5 (18.5) % of predicted. The group quitted ‘>5 years’ showed significantly lower rates of progression of emphysema compared to current smokers, 1.07% and 1.12% per year, respectively (p<0.001). Current smokers had a yearly FEV₁-decline of 69 ml, while subjects quit smoking >5 years had a yearly decline of 57.5 ml (p<0.001).

Conclusion

Quit smoking >5 years significantly slows the rate of emphysema progression and lung function decline.

Trial registration

Registered at http://www.trialregister.nl with trial number ISRCTN63545820.     

Low-dose CT measurements of airway dimensions and emphysema associated with airflow limitation in heavy smokers: a cross sectional study

Background

Increased airway wall thickness (AWT) and parenchymal lung destruction both contribute to airflow limitation. Advances in computed tomography (CT) post-processing imaging allow to quantify these features. The aim of this Dutch population study is to assess the relationships between AWT, lung function, emphysema and respiratory symptoms.

Methods

AWT and emphysema were assessed by low-dose CT in 500 male heavy smokers, randomly selected from a lung cancer screening population. AWT was measured in each lung lobe in cross-sectionally reformatted images with an automated imaging program at locations with an internal diameter of 3.5 mm, and validated in smaller cohorts of patients. The 15^th percentile method (Perc15) was used to assess the severity of emphysema. Information about respiratory symptoms and smoking behavior was collected by questionnaires and lung function by spirometry.

Results

Median AWT in airways with an internal diameter of 3.5 mm (AWT_3.5) was 0.57 (0.44 - 0.74) mm. Median AWT in subjects without symptoms was 0.52 (0.41-0.66) and in those with dyspnea and/or wheezing 0.65 (0.52-0.81) mm (p<0.001). In the multivariate analysis only AWT_3.5 and emphysema independently explained 31.1%and 9.5%of the variance in FEV₁%predicted, respectively, after adjustment for smoking behavior.

Conclusions

Post processing standardization of airway wall measurements provides a reliable and useful method to assess airway wall thickness. Increased airway wall thickness contributes more to airflow limitation than emphysema in a smoking male population even after adjustment for smoking behavior.     

CT Air Trapping Is Independently Associated with Lung Function Reduction over Time

Purpose

We aimed to study the association between lung function decline and quantitative computed tomography (CT) air trapping.

Materials and Methods

Current and former heavy smokers in a lung cancer screening trial underwent volumetric low-dose CT in inspiration and expiration. Spirometry was obtained at baseline and after 3 years. The expiratory to inspiratory ratio of mean lung density (E/I-ratio_MLD) was used to quantify air trapping. CT emphysema was defined as voxels in inspiratory CT below −950 Hounsfield Unit. Linear mixed modeling was used to determine the association between CT air trapping and lung function.

Results

We included 985 subjects with a mean age of 61.3 years. Independent of CT emphysema, CT air trapping was significantly associated with a reduction in forced expiratory volume in one second (FEV₁) and the ratio of FEV₁ over the forced vital capacity (FEV₁/FVC); FEV₁ declines with 33 mL per percent increase in CT air trapping, while FEV₁/FVC declines 0.58% per percent increase (both p<0.001). CT air trapping further elicits accelerated loss of FEV₁/FVC (additional 0.24% reduction per percent increase; p = 0.014).

Conclusion

In a lung cancer screening cohort, quantitatively assessed air trapping on low-dose CT is independently associated with reduced lung function and accelerated decline of FEV₁/FVC.     

Semi-Automatic Quantification of Subsolid Pulmonary Nodules: Comparison with Manual Measurements

Rationale

Accurate measurement of subsolid pulmonary nodules (SSN) is becoming increasingly important in the management of these nodules. SSNs were previously quantified with time-consuming manual measurements. The aim of the present study is to test the feasibility of semi-automatic SSNs measurements and to compare the results to the manual measurements.

Methods

In 33 lung cancer screening participants with 33 SSNs, the nodules were previously quantified by two observers manually. In the present study two observers quantified these nodules by using semi-automated nodule volumetry software. Nodules were quantified for effective diameter, volume and mass. The manual and semi-automatic measurements were compared using Bland-Altman plots and paired T tests. Observer agreement was calculated as an intraclass correlation coefficient. Data are presented as mean (SD).

Results

Semi-automated measurements were feasible in all 33 nodules. Nodule diameter, volume and mass were 11.2 (3.3) mm, 935 (691) ml and 379 (311) milligrams for observer 1 and 11.1 (3.7) mm, 986 (797) ml and 399 (344) milligrams for observer 2, respectively. Agreement between observers and within observer 1 for the semi-automatic measurements was good with an intraclass correlation coefficient >0.89. For observer 1 and observer 2, measured diameter was 8.8% and 10.3% larger (p<0.001), measured volume was 24.3% and 26.5% larger (p<0.001) and measured mass was 10.6% and 12.0% larger (p<0.001) with the semi-automatic program compared to the manual measurements.

Conclusion

Semi-automated measurement of the diameter, volume and mass of SSNs is feasible with good observer agreement. Semi-automated measurement makes quantification of mass and volume feasible in daily practice.     

Does a 5500-km swim trial stimulate early sexual maturation in the European eel (Anguilla anguilla L.)?

The catadromous European eel (Anguilla anguilla L.) undertakes a 6000-km spawning migration from its freshwater habitats to the Sargasso Sea. In large Blazka swim tunnels of 127 l, the physiological effect of such a prolonged swimming performance on sexual maturation in adult female eels was investigated. Two groups of eels were placed in swim tunnels for 173 days, one group was able to swim at 0.5 body lengths/second (Swim group) covering a distance of c. 5500-km over the experimental period, and one group kept in static (End Control group). A control group was sampled at the start of the experiment in order to determine the initial stage of reproductive development (Initial Control group). At the end of the swim trial, the maturation parameters 11-ketotestosterone, pituitary levels of LH and plasma levels of estradiol were higher (although not significantly) in the Swim compared to the End Control group. In addition, no significant differences were observed in most measured morphometric and reproductive parameters, including eye-index, gonadosomatic index, hepatosomatic index, and plasma levels of vitellogenin, cortisol and melanophore-stimulating hormone (MSH). Also, pituitary levels of both MSH, and adrenocorticotropic hormone (ACTH) were unaffected. In contrast, the oocyte diameter was found to be significantly higher in the Swim compared to the End Control group. Based on these observations we conclude that a period of prolonged swimming might be a physiological stimulus necessary for the onset of maturation in the European eel.     

Diagnostic Accuracy of Computer-Aided Detection of Pulmonary Tuberculosis in Chest Radiographs: A Validation Study from Sub-Saharan Africa

Background

Chest radiography to diagnose and screen for pulmonary tuberculosis has limitations, especially due to inter-reader variability. Automating the interpretation has the potential to overcome this drawback and to deliver objective and reproducible results. The CAD4TB software is a computer-aided detection system that has shown promising preliminary findings. Evaluation studies in different settings are needed to assess diagnostic accuracy and practicability of use.

Methods

CAD4TB was evaluated on chest radiographs of patients with symptoms suggestive of pulmonary tuberculosis enrolled in two cohort studies in Tanzania. All patients were characterized by sputum smear microscopy and culture including subsequent antigen or molecular confirmation of Mycobacterium tuberculosis (M.tb) to determine the reference standard. Chest radiographs were read by the software and two human readers, one expert reader and one clinical officer. The sensitivity and specificity of CAD4TB was depicted using receiver operating characteristic (ROC) curves, the area under the curve calculated and the performance of the software compared to the results of human readers.

Results

Of 861 study participants, 194 (23%) were culture-positive for M.tb. The area under the ROC curve of CAD4TB for the detection of culture-positive pulmonary tuberculosis was 0.84 (95% CI 0.80–0.88). CAD4TB was significantly more accurate for the discrimination of smear-positive cases against non TB patients than for smear-negative cases (p-value<0.01). It differentiated better between TB cases and non TB patients among HIV-negative compared to HIV-positive individuals (p<0.01). CAD4TB significantly outperformed the clinical officer, but did not reach the accuracy of the expert reader (p = 0.02), for a tuberculosis specific reading threshold.

Conclusion

CAD4TB accurately distinguished between the chest radiographs of culture-positive TB cases and controls. Further studies on cost-effectiveness, operational and ethical aspects should determine its place in diagnostic and screening algorithms.     

The human neonatal small intestine has the potential for arginine synthesis; developmental changes in the expression of arginine-synthesizing and -catabolizing enzymes

Background  

Milk contains too little arginine for normal growth, but its precursors proline and glutamine are abundant; the small intestine of rodents and piglets produces arginine from proline during the suckling period; and parenterally fed premature human neonates frequently suffer from hypoargininemia. These findings raise the question whether the neonatal human small intestine also expresses the enzymes that enable the synthesis of arginine from proline and/or glutamine. Carbamoylphosphate synthetase (CPS), ornithine aminotransferase (OAT), argininosuccinate synthetase (ASS), arginase-1 (ARG1), arginase-2 (ARG2), and nitric-oxide synthase (NOS) were visualized by semiquantitative immunohistochemistry in 89 small-intestinal specimens.     

Depletion of high energy phosphates implicates post-exercise mortality in carp and trout; an in vivo 31P-NMR study

As in vivo 31P-Nuclear Magnetic Resonance spectroscopy is currently the state of the art method to measure continuously intracellular pH (pH(i)) and energy status of muscle tissue, we used this method to study the recovery from exhaustive exercise. The biochemical changes during recovery are not well understood and it was suggested that post-exercise mortality could be caused by low pH(i); other studies however indicate that energy depletion might be more important. To analyse the mechanism of post-exercise recovery pH(i), ATP, P(i), and PCr must be measured at the same time, which is possible using in vivo 31P-NMR. Common carp and rainbow trout of about 100 g were exercised to exhaustion in a swim tunnel. After swimming 10 h at 1.5 body lengths (BL)/s (aerobic control), 50% of the fish were forced to swim at 6 BL/s until exhaustion. Recovery of energy rich phosphates was found to be faster in carp (1.2-1.9 h) than in trout (1.5-2.3 h). The same applied for the recovery from acidosis, which took 1.75 h in carp and 5.75 h in trout. In parallel experiments the energy phosphates and lactate levels were measured in liver, red muscle, and white muscle. Exhaustion caused a significant drop in the energy status of red and white muscle tissue of trout and carp (corroborates NMR data), while no change at all was observed in liver tissue. The lactate levels were increased in the muscle but not in liver and blood. While all experimental animals looked healthy after exhaustion, 40-50% of the carp as well as trout died during the recovery phase. The energy status of those individuals measured by 31P-NMR was much lower than that of the survivors, while in contrast there was no difference in pH(i). Thus, it appears that not acidosis but depletion of high energy phosphates disabled muscle function and therefore may have been the cause of death of the non-survivors.     

Cost of transport and optimal swimming speed in farmed and wild European silver eels (Anguilla anguilla)

A swimming speed of 0.4 meters per second (m s(-1)) is the minimal speed for European female silver eels to reach the spawning sites in the Sargasso Sea in time. As silver eels cease feeding when they start their oceanic migration, the cost of transport (COT) should be minimised and the swimming speed optimised to attain the highest energetic efficiency. In this study, we have investigated the optimal swimming speed (U(opt)) of silver eels since U(opt) may be higher than the minimal swimming speed and is more likely to resemble the actual cruise speed. A variety of swimming tests were performed to compare endurance swimming between farmed eels and wild eels, both in freshwater and in seawater. The swimming tests were run with 101 silver female eels (60-96 cm, 400-1500 g) in 22 Blazka-type swim tunnels in a climatised room at 18 degrees C with running freshwater or seawater. Tests were run at 0.5-1.0 m s(-1) with increments of 0.1 m s(-1), and either 2 h or 12 h intervals. Remarkably, both tests revealed no changes in oxygen consumption (M O2) and COT over time. U(opt) values ranged between 0.61 and 0.68 m s(-1) (0.74-1.02 BL s(-1)) for the different groups and were thus 53-70% higher than the minimal speed. At U(opt), the COT was 37-50 mg O2 kg(-1) km(-1). These relatively very low values confirm our earlier observations. COT values in seawater were about 20% higher than in freshwater. Assuming that migrating female silver eels cruise at their U(opt), they will be able to cover the distance to the Sargasso Sea in 3-4 months, leaving ample time for final maturation and finding mates.