Deborah L. Preston

Aging influences multiple incidices of oxidative stress in the aortic media of the Fischer 344/NNia × Brown Norway/BiNia rat

Here, we determine the influence of aging on multiple markers of oxidative stress in the aorta of adult (6-month), aged (30-month) and very aged (36-month) Fischer 344/NNiaHSd × Brown Norway/BiNia (F344/N × BN) rats. Compared to adults, increases in as determined by oxidation of hydroethidine (HE) to ethidium (Et) were increased 79.7 ± 7.0% in 36-month aortae and this finding was highly correlated with increases in medal thickness (r = 0.773, p < 0.01) and total protein nitration (r = 0.706, p < 0.01) but not Ki67, a marker for cell proliferation. Regression analysis showed that increases in aortic superoxide anion () with aging were significantly correlated with changes in the expression and/or regulation of proteins involved in metabolic (AMPK-α), signaling (mitogen activated protein kinases (MAPKs) along with c-Src), apoptotic (Bax, Bcl-2, Traf-2) and transcriptional (NF-κB) activities. These results suggest that the aging F344/N × BN aorta may be highly suited for unraveling the molecular events that lead to age-associated alterations in aortic oxidative stress.

Does Helicobacter pylori protect against eosinophilic esophagitis in children

Helicobacter pylori infection and eosinophilic esophagitis (EoE) in children seem to have a reversed association with socioeconomic status (hygienic condition) and allergy conditions. While Hp infection (Hp) is highly associated with poor hygiene and/or poor socioeconomic status, but not with allergic conditions (asthma, rhinitis, etc.), EoE has the opposite epidemiological relationship (high association with allergy but low with low hygienic conditions).

Diabetes alters contraction-induced mitogen activated protein kinase activation in the rat soleus and plantaris.

The prescription of anaerobic exercise has recently been advocated for the management of diabetes; however exercise-induced signaling in diabetic muscle remains largely unexplored. Evidence from exercise studies in nondiabetics suggests that the extracellular-signal-regulated kinases (Erk1/2), p38, and c-JUN NH2-terminal kinase (Jnk) mitogen-activated protein kinases (MAPKs) are important regulators of muscle adaptation. Here, we compare the basal and the in situ contraction-induced phosphorylation of Erk1/2- p38- and Jnk-MAPK and their downstream targets (p90rsk and MAPKAP-K2) in the plantaris and soleus muscles of normal and obese (fa/fa) Zucker rats. Compared to lean animals, the time course and magnitude of Erk1/2, p90rsk and p38 phosphorylation to a single bout of contractile stimuli were greater in the plantaris of obese animals. Jnk phosphorylation in response to contractile stimuli was muscle-type dependent with greater increases in the plantaris than the soleus. These results suggest that diabetes alters intramuscular signaling processes in response to a contractile stimulus.

Uniaxial stretch-induced regulation of mitogen-activated protein kinase, Akt and p70S6 kinase in the ageing Fischer 344 × Brown Norway rat aorta

The effects of ageing on the cardiovascular system contribute to substantial alterations in cellular morphology and function. The variables regulating these changes are unknown; however, one set of signalling molecules that may be of particular importance in mediating numerous cellular responses, including control of cell growth, differentiation and adaptation, are the proteins associated with the mitogen‐activated protein kinase (MAPK) signalling systems. The MAPKs, in conjunction with the p70 S6k signalling cascade, have emerged as critical components for regulating numerous mechanotransduction‐related cellular responses. Here we investigate the ability of uniaxial stretch to activate the MAPK and p70 S6k pathways in adult (6‐month‐old), aged (30‐month‐old) and very aged (36‐month‐old) Fischer 344/NNiaHSd × Brown Norway/BiNia (FBN) rats. Western blotting of the MAPK family proteins extracellular signal‐regulated kinase (Erk) 1/2, p38‐ and c‐Jun NH2‐terminal kinase (Jnk)‐MAPKs showed differential expression and activation between these proteins with age. An acute 15 min interval of 20% uniaxial stretch using an ex vivo aortic preparation demonstrated similar regulation of Erk1/2, p38‐ and Jnk‐MAPK. However, ageing altered uniaxial induced p70 S6k pathway signalling. These observations confirm previous data demonstrating that MAPK proteins are mechanically regulated and also suggest that p70 S6k signalling expression and activation are controlled differently with ageing. Taken together, these data may help to explain, in part, the age‐related changes in vascular morphology, function and response to injury.

Upper Endoscopy in Children Do Symptoms Predict Positive Findings

Upper endoscopy (esophagogastroduodenoscopy or EGD) is an important diagnostic tool for many gastrointestinal symptoms. In recent years, the number of EGDs has increased dramatically. Unfortunately, the rate of negative (normal) EGD in children is high, approximating 50% of all procedures. To decrease the cost of EGD procedures, it is important to assess which clinical symptom would detect positive findings. This information may also be valuable in improving the referral practices of the primary care physicians for EGD. In a retrospective study, we investigated the pathological yield of the first EGD in children referred for various symptoms. Abdominal pain was the most common referral symptom and the best predictor of positive EGD, reaching an accuracy level of 79.9%. All other investigated symptoms had less than 50% accuracy. We concluded that most gastrointestinal symptoms in children have a poor predictive value for positive EGD. A cost–benefit analysis of EGD in children is needed.

3,4,5-Trichloroaniline Nephrotoxicity in Vitro: Potential Role of Free Radicals and Renal Biotransformation

Chloroanilines are widely used in the manufacture of drugs, pesticides and industrial intermediates. Among the trichloroanilines, 3,4,5-trichloroaniline (TCA) is the most potent nephrotoxicant in vivo. The purpose of this study was to examine the nephrotoxic potential of TCA in vitro and to determine if renal biotransformation and/or free radicals contributed to TCA cytotoxicity using isolated renal cortical cells (IRCC) from male Fischer 344 rats as the animal model. IRCC (~4 million cells/mL; 3 mL) were incubated with TCA (0, 0.1, 0.25, 0.5 or 1.0 mM) for 60–120 min. In some experiments, IRCC were pretreated with an antioxidant or a cytochrome P450 (CYP), flavin monooxygenase (FMO), cyclooxygenase or peroxidase inhibitor prior to incubation with dimethyl sulfoxide (control) or TCA (0.5 mM) for 120 min. At 60 min, TCA did not induce cytotoxicity, but induced cytotoxicity as early as 90 min with 0.5 mM or higher TCA and at 120 min with 0.1 mM or higher TCA, as evidenced by increased lactate dehydrogenase (LDH) release. Pretreatment with the CYP inhibitor piperonyl butoxide, the cyclooxygenase inhibitor indomethacin or the peroxidase inhibitor mercaptosuccinate attenuated TCA cytotoxicity, while pretreatment with FMO inhibitors or the CYP inhibitor metyrapone had no effect on TCA nephrotoxicity. Pretreatment with an antioxidant (α-tocopherol, glutathione, ascorbate or N-acetyl-l-cysteine) also reduced or completely blocked TCA cytotoxicity. These results indicate that TCA is directly nephrotoxic to IRCC in a time and concentration dependent manner. Bioactivation of TCA to toxic metabolites by CYP, cyclooxygenase and/or peroxidase contributes to the mechanism of TCA nephrotoxicity. Lastly, free radicals play a role in TCA cytotoxicity, although the exact nature of the origin of these radicals remains to be determined.

Role of Serum Biomarkers in Early Detection of Non-Alcoholic Steatohepatitis and Fibrosis in West Virginian Children

Background Obesity, an epidemic among West Virginia children, as well as insulin resistance (IR), is well-established contributors to nonalcoholic steatohepatitis (NASH). Progression of NASH can lead to hepatic fibrosis and cirrhosis, making early detection imperative. The standard for diagnosing NASH is histologically via liver biopsy, which is highly invasive and generally contraindicated in children. By studying serum biomarkers associated with NASH, we aim to identify high risk children who can benefit from a less invasive, alternative approach to the early detection of NASH. Methods Seventy one children were prospectively recruited and divided into 3 groups: normal weight without IR (control), obese without IR, and obese with IR. Serum samples were drawn for each patient and biomarker levels were assessed via ELISA kits. Results Obese without IR and obese with IR patients had significantly elevated levels of lipid metabolism and accumulation markers (FGF-21, NEFA, FATP5, ApoB), oxidative stress markers (dysfunctional HDL, 8-Isoprostane), inflammatory markers(dysfunctional HDL, CK-18) and apoptosis markers (CK-18) compared to control patients (p<0.02). Bilirubin (an antioxidant) was significantly decreased in the obese without IR and obese with IR patients compared to control (p<0.02). Conclusion This study showed a correlation between obesity, IR, and biomarkers associated with NASH in pediatrics patients from West Virginia, with obese with IR patients showing the strongest correlation. These findings support the clinical application of these serum biomarkers as a less invasive method for early detection of NASH and hepatic fibrosis.

Rate of Celiac Disease in Children: View From the Endoscopy Suite

Objectives: The low rate of celiac disease diagnosed in children from the United States may be limited by the practice of “serology-led” diagnosis. The frequency of seronegative celiac disease is unknown, but is underestimated in children and may result in misdiagnosis of celiac disease. The aim of the present study was to investigate the rate of celiac disease after upper endoscopy (esophagogastroduodenescopy [EGD]) with no prior positive celiac serology compared with the rate of celiac disease followed by positive serology. Methods: Charts of all of the first diagnostic EGDs in children (2009–2013) were retrospectively reviewed. Patients with confirmed celiac disease were divided into 4 groups: group A, positive EGD/positive serology (histology-led diagnosis); group B, positive serology/positive histology (serology-led diagnosis); group C, positive histology followed by negative serology (control 1); and group D, positive serology followed by negative histology (control 2). Results: A total of 761 upper endoscopic charts were reviewed. Of these, 15 children were confirmed with celiac disease (1.97%). There was no significant difference in the demographic data or clinical symptoms between group A and group B. No significant difference was observed in the rate of celiac disease between histology-led celiac diagnosis (group A) and serology-led celiac diagnosis (group B) (1.18% vs 0.79%, P = 0.273). Conclusions: The rate of celiac disease in endoscopy-led diagnosis was comparable to that in the serology-led diagnosis, suggesting that to increase the detection of celiac disease in children, an adequate number of intestinal biopsies should be performed in every diagnostic upper endoscopic procedure.

4-Amino-2-chlorophenol: Comparative In Vitro Nephrotoxicity and Mechanisms of Bioactivation

Chlorinated anilines are nephrotoxicants both in vivo and in vitro. The mechanism of chloroaniline nephrotoxicity may occur via more than one mechanism, but aminochlorophenol metabolites appear to contribute to the adverse in vivo effects. The purpose of this study was to compare the nephrotoxic potential of 4-aminophenol (4-AP), 4-amino-2-chlorophenol (4-A2CP), 4-amino-3-chlorophenol (4-A3CP) and 4-amino-2,6-dichlorophenol (4-A2,6DCP) using isolated renal cortical cells (IRCC) from male Fischer 344 rats as the model and to explore renal bioactivation mechanisms for 4-A2CP. For these studies, IRCC (∼4×10(6)cells/ml) were incubated with an aminophenol (0.5 or 1.0mM) or vehicle for 60min at 37°C with shaking. In some experiments, cells were pretreated with an antioxidant or cytochrome P450 (CYP), flavin-containing monooxygenase (FMO), peroxidase or cyclooxygenase inhibitor prior to 4-A2CP (1.0mM). Lactate dehydrogenase (LDH) release served as a measure of cytotoxicity. The order of decreasing nephrotoxic potential in IRCC was 4-A2,6-DCP>4-A2CP>4-AP>4-A3CP. The cytotoxicity induced by 4-A2CP was reduced by pretreatment with the peroxidase inhibitor mercaptosuccinic acid, and some antioxidants (ascorbate, glutathione, N-acetyl-l-cysteine) but not by others (α-tocopherol, DPPD). In addition, pretreatment with the iron chelator deferoxamine, several CYP inhibitors (except for the general CYP inhibitor piperonyl butoxide), FMO inhibitors or indomethacin (a cyclooxygenase inhibitor) failed to attenuate 4-A2CP cytotoxicity. These results demonstrate that the number and ring position of chloro groups can influence the nephrotoxic potential of 4-aminochlorophenols. In addition, 4-A2CP may be bioactivated by cyclooxygenase and peroxidases, and free radicals appear to play a role in 4-A2CP cytotoxicity.

Colon cleansing protocol in children: research conditions vs. clinical practice

Background and study aims  Colon preparation rates are the limiting factor for a successful diagnostic colonoscopy in children. Different colon cleansing protocols have been published for use in children. Unfortunately, the applicability of those published research protocols has not been formally evaluated in routine clinical practice. We investigated the success rate of our previously published colon cleansing protocol as utilized in our clinical practice. Patients and methods  This was a retrospective study. In the clinical practice, the colon cleansing protocol included PEG-3350 at a dose of 2 g/kg/day plus Dulcolax (Bisacodyl, Boehringer Ingelheim, TX USA) 5 mg/day for 2 days. Adequate colon preparation was graded between 1 – 5, as previously described, and grade ≥ 4.0 was considered an adequate preparation. Patients were instructed to complete a questionnaire that included PEG-3350 dose, number of stools per day, consistency of each stool, and side effects (vomiting, abdominal pain). Clinical and endoscopic results were compared between the protocol under research conditions and routine practice. Results  The success rate of the colon preparation in our clinical practice was similar to the results observed under our research protocol (75 % vs. 73.6 %). Moreover, the total number of stools, stool consistency, and the intubation rate of the terminal ileum were also similar. We concluded, that in our experience, the colon cleansing protocol used under research conditions was effective and appropriate for use in routine clinical practice. Conclusion  We recommend testing each new protocol under the routine conditions of clinical practice to confirm its applicability for general practitioners.