Nader Yousef - Academia.edu (original) (raw)

Papers by Nader Yousef

Four active ingredients used in fire ant bait products are currently approved under the Federal I... more Four active ingredients used in fire ant bait products are currently approved under the Federal Imported Fire Ant Quarantine for treating nursery stock, including fenoxycarb, hydramethylnon, pyriproxyfen, and (S)-methoprene. Bait products containing one or more of these active ingredients and labeled for use in nurseries include Amdro  Pro, Award  Fire Ant Bait, Distance  Fire Ant Bait, Extinguish  Professional Fire Ant Bait, or Extinguish  Plus (Table 1). Although some information in this publication applies to general bait use, the goal of the publication is to provide information on baits that can be used in the Federal Quarantine for commercial nurseries. II. GENERAL BAIT INFORMATION A. What is a Fire Ant Bait? A bait has three essential parts: 1) a toxicant or insect-controlling chemical (active ingredient), 2) a food substance or attractant (e.g., soybean oil), and 3) a distributing particle that carries both the toxicant and food substance (e.g., corncob grit). Generally, the insecticide active ingredient is dissolved in the oil portion of the bait and the ants consume the insecticide while feeding on the oil. Baits are particularly effective against social insects like ants that forage for food and bring it back to the colony. B. Bait Features: 1) Slow-acting toxicant. A slow-acting toxicant allows the product to be distributed to other members of the colony before the original forager dies. 2) Non-repellent properties. No part of the bait can be repellent to the target fire ants. 3) Effective at a wide range of doses. As bait ingredients are passed between members of the colony (i.e., trophallaxis), the insecticide can become progressively diluted. Therefore, the insecticide must work at a wide range of doses. 4) Minimal non-target effects. Ideally, baits would be more attractive to fire ants than other insects. However, native ants will forage fire ant baits and some impact can occur, especially when baits are broadcast. Native ants are beneficial because they reduce site reinfestation by fire ants. 5) Generally lower risk to handlers than traditional insecticide products. The insecticide in baits is formulated at very low concentrations (often 0.5 to 1%) and the toxic action of some baits (e.g., insect growth regulators) are more specific to insects, resulting in fewer undesirable effects on non-targets. Nonetheless, applicators still need to use the same caution when handling baits as with any pesticide product and the personal protective equipment (PPE) listed on the label must be worn to comply with the law (Table 1). 6) Generally safe to the environment. Baits have minimal environmental impact if used according to the label. All bait insecticides approved for the Federal Quarantine are toxic to aquatic organisms and should never be applied to water or sites where rain or irrigation could wash the bait into surrounding water bodies.

Journal of Pediatric Gastroenterology & Nutrition, 2010

Investigators may have concerns that parents will not allow their children to participate in plac... more Investigators may have concerns that parents will not allow their children to participate in placebo-controlled trials (PCTs). The aim of the present study was to identify potential differences between parental perceptions in families who successfully completed (CO) a clinical trial compared with those who were noncompleters (NC). Parents of both CO and NC children enrolled in pediatric gastrointestinal studies performed in the previous year were eligible. NC were defined as those who were screen failures or treatment nonresponders or had adverse events. One hundred seven parents were identified and mailed a 26-item questionnaire eliciting perceptions regarding participation in research. Questionnaires were sent 6 months after participation in research ended. Seventy-eight (69%) parents returned the survey. Characteristics included maternal responders (98%), English as primary language (97%), and education beyond high school (85%). Five parents (4.7%) had children involved in previous research trials. There were no significant differences in responses found between CO (n = 49; 63%) and NC (n = 29; 37%) in regard to importance of research, perceptions of risk to child, benefits to child, and more attention in the study. Statistical significance was approached in regard to the comfort with the research team, with a greater portion of CO stating that the researcher put the parent at ease and the NC feeling less positive about the interaction (P = 0.05). A positive perception about participation in research is not stratified by successful completion of a PCT. These results should encourage investigators and institutional review boards that if properly designed and conducted, pediatric PCTs can result in a positive experience for parents.

Journal of Pediatric Gastroenterology and Nutrition, 2006

Background: The relationship between the increased intestinal permeability observed in several ac... more Background: The relationship between the increased intestinal permeability observed in several acute and chronic diseases and the expression of tight junctions (TJ) proteins is not well established. Our aim was to investigate the expression at transcriptional level of 3 transmembrane TJ proteins, Occludin, Claudin-1, Claudin-2 and of 2 scaffold TJ proteins, zonula occludens-1 (ZO-1) and Myosin 9B in intestinal biopsies from patients affected by celiac disease (CD), Crohn's disease (CrD), peptic ulcer disease (PUD) and type 1 diabetes (IDDM). Methods: Samples of small intestinal mucosa were taken from the second/third portion of the duodenum from all the subjects studied. After total RNA extraction and cDNA synthesis, quantitative real time polymerase chain reaction assays with SYBR Green was performed. Data were normalized by using18S rRNA as standard. Results: Shown in the Table. A significant down-regulation of all 5 genes studied was observed in patients affected by celiac disease before gluten-free diet, while no significant change was observed in IDDM patients. Conclusions: The down-regulation of TJ transmembrane or/and intracellular components observed in all but IDDM might explain the increased intestinal permeability reported in these pathological conditions. The meaning of TJs disruption in the pathogenesis of each of this pathological condition warrants further investigation. The normal transcriptional level observed in celiacs on GFD suggests that the down-regulation of TJs in CD is reversible and secondary to gliadin exposure rather than to a genetic predisposition.

Journal of Pediatric Gastroenterology and Nutrition, 2005

Journal of Economic Entomology, 2008

The key to an effective pest management program for the emerald ash borer, Agrilus planipennis Fa... more The key to an effective pest management program for the emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera Buprestidae), is a survey program equipped with tools for detecting and delimiting populations. We studied the effects of trap design, color, and placement on the efÞcacy of sticky traps for capturing the emerald ash borer. There were signiÞcant differences in trap catch along a transect gradient from wooded to open Þeld conditions, with most beetles being caught along the edge, or in open Þelds, 15Ð25 m outside an ash (Fraxinus spp. L.) (Oleaceae) woodlot. Greater emerald ash borer catch occurred on purple traps than on red or white traps. Traps placed in the mid-canopy of ash trees (13 m) caught signiÞcantly more beetles than those placed at ground level. We also describe a new trap design, a three-sided prism trap, which is relatively easy to assemble and deploy.

Gastroenterology, 2009

Gastroenterology, Volume 136, Issue 5, Pages A-513, May 2009, Authors:Wendy A. Henderson; Tara J.... more Gastroenterology, Volume 136, Issue 5, Pages A-513, May 2009, Authors:Wendy A. Henderson; Tara J. Taylor; Ravi Shankar; Jessica Gill; David Kleiner; Nader N. Youssef.

Gastroenterology, 2010

Gastroenterology, Volume 138, Issue 5, Pages S-357, May 2010, Authors:Wendy A. Henderson; Tara J.... more Gastroenterology, Volume 138, Issue 5, Pages S-357, May 2010, Authors:Wendy A. Henderson; Tara J. Taylor; Ravi Shankar; Miriam R. Anver; Donna O. Butcher; Nader N. Youssef.

Gastroenterology, 2003

was previously shown to be involved in the secretory effects of bile acids on the colonocytes, th... more was previously shown to be involved in the secretory effects of bile acids on the colonocytes, the potential involvement of histamine receptors was also examined in current studies. Both cimetidine (1 raM) and diphenhydramine (0.1raM), H2 and H1 histamine receptor antagonists respectively, had no effect on inhibition of 36C1 uptake by TDC. In conclusion, our studies, provide direct evidence for inhibition of human intestinal luminal CI'/OH (HCO~) exchange activity by bile acids. The results of our studies demonstrate that bile acid effects on the apical CI/OH exchange in Caco2 cells are not mediated via histamine receptors and involve a cAMP-independent but Ca + +, PKC and PI3 kinase-dependent pathways.

BMC Research Notes, 2010

Background: Abdominal pain of unknown origin affects up to 20% of school-aged children. Evaluatio... more Background: Abdominal pain of unknown origin affects up to 20% of school-aged children. Evaluation of children is symptom-based without clear guidelines to investigate molecular mechanisms of abdominal pain. Aberrant molecular mechanisms may increase intestinal permeability leading to interactions between the immune and nervous systems, subclinical inflammation, and visceral pain. This study evaluated the association between interleukin-6 (IL-6), mast cell infiltrates, and serotonin (5-HT) levels in gastrointestinal (GI) biopsies, with perceived abdominal pain in a pediatric cohort. Methods: Clinical data and biopsy samples from pediatric patients (n = 48) with chronic abdominal pain, with and without inflammation were included. Formalin-fixed paraffin-embedded GI biopsies were sectioned and immunohistochemistry performed for IL-6 and 5-HT; mast cells were identified with toluidine blue stain. Histological findings were compared to self-reported abdominal pain between groups. Results: There was significantly greater IL-6 immunoreactivity in biopsies with confirmed histologic inflammation (p = 0.004). There was a greater number of mast cells per HPF in non-inflammatory biopsies (3.5 ± 2.9) compared to the inflammatory biopsies (2.6 ± 1.8) p = 0.049. The non-inflammatory biopsy group was significantly less likely to respond to standard treatment as evidenced by higher pain reports (p = .018). Mast cells (p = .022) and 5-HT (p = .02) were significantly related to abdominal pain scores. Conclusions: A potential association between self-reported abdominal pain, number of mast cells, and 5-HT levels, which may contribute to perceived GI pain in pediatric patients may exist.

Journal of Pediatric Gastroenterology and Nutrition

The objective of this study was to investigate the effect of chronic constipation on children's q... more The objective of this study was to investigate the effect of chronic constipation on children's quality of life. Methods: From October 2002 to November 2003, 224 children (140 male, 84 female, aged 10.6 6 2.9 years) and 224 parents were evaluated by a health related quality of life tool during initial outpatient consultation. Children with constipation (n = 80) were compared with controls with inflammatory bowel disease (n = 42), controls with gastroesophageal reflux disease (n = 56), and with healthy children (n = 46). Results: Children with constipation had lower quality of life scores than did those with inflammatory bowel disease (70 versus 84; P , 0.05), gastroesophageal reflux disease (70 versus 80; P , 0.05), and healthy children (70 versus 88; P , 0.05). Children with constipation reported lower physical scores than did inflammatory bowel disease patients (75 versus 85; P , 0.02), gastroesophageal reflux disease patients (75 versus 85; P , 0.05), or healthy children (75 versus 87; P , 0.05). Parents of children with constipation reported lower scores than did their children (61 versus 70; P , 0.05). Children with constipation had longer duration of symptoms than did the controls with inflammatory bowel disease and gastroesophageal reflux disease (43.8 months versus 14.2 months; P , 0.001). Prolonged duration of symptoms for children with constipation correlated with lower parent-reported scores (P , 0.002). Conclusions: At initial evaluation, children with constipation have a lower quality of life than do children with inflammatory bowel disease or gastroesophageal reflux disease. Self-reported lower scores may be a reflection of impaired physical ability. Parental perceptions of low quality of life are probably impacted by the duration of their child's symptoms and by family members with similar complaints. Practitioners should be aware of the high level of parental concern and the relatively low self-reported and parent-reported quality of life in children with chronic constipation as they plan therapy.