Home About us Contact
|
Home About us Contact | ||
|
|
||
Predominant Response (predominant + response)
Selected AbstractsIgG Subclass Responses in Childhood Helicobacter pylori Duodenal Ulcer: Evidence of T-Helper Cell Type 2 ResponsesHELICOBACTER, Issue 4 2004David I. Campbell ABSTRACT Background., Duodenal ulcer in adults chronically infected with Helicobacter pylori is associated with a polarized T-helper cell type 1 (Th1) mucosal immune response, with a predominantly immunoglobulin G2 (IgG2) systemic specific response. It has been suggested that children colonized by H. pylori also produce a mucosal Th1 response, but there are few studies that have measured IgG subclass responses in children with duodenal ulcer. Materials and methods., Seven children with endoscopically proven duodenal ulcer and H. pylori infection and 18 children with biopsy proven H. pylori infection but no duodenal ulcer had relative concentrations of IgG subclass responses (IgGsc) against H. pylori antigens measured by ELISA. Eighteen IgG seropositive adults acted as controls. The range of antigens recognised by IgG1 and IgG2 subclass responses were investigated by Western blots. Results., There were no differences in mean IgGsc responses between children with or without duodenal ulcer. Adults produced an IgG2 predominant response. Western blots showed no qualitative differences in antigens recognised by IgG1 or IgG2. Conclusion., Children with duodenal ulcer, in contrast to adults, produce an IgGsc response consistent with a mucosal Th2 response to H. pylori regardless of the presence of duodenal ulceration. This suggests that disease causation amongst children with H. pylori associated duodenal ulceration may not be dependant upon a mucosal Th1 biased response. [source] Lower oesophageal sphincter relaxation evoked by stimulation of the dorsal motor nucleus of the vagus in ferretsNEUROGASTROENTEROLOGY & MOTILITY, Issue 3 2002T. P. Abrahams Abstract, An understanding of the neural control of lower oesophageal sphincter (LOS) relaxation is clinically relevant because transient LOS relaxations (TLOSRs) are a mechanism of acid reflux into the oesophagus. Preganglionic motor neurones innervating the LOS are localized in the dorsal motor nucleus of the vagus (DMV). Based on a single study in cats, it is now widely accepted that these neurones are functionally organized into two separate populations, such that stimulation of the caudal and rostral DMV evokes LOS relaxation and contraction, respectively. Our goal was to map the functional LOS responses to chemical stimulation in the DMV and nucleus tractus solitarius (NTS) of ferrets, an animal model commonly used for conscious studies on TLOSRs, and to test whether DMV-evoked LOS relaxation is mediated through hexamethonium-sensitive vagal-inhibitory pathways to the LOS. We used miniaturized manometry with Dentsleeve to monitor LOS and oesophageal pressures in decerebrate unanaesthetized ferrets. LOS relaxation was evoked readily in response to gastric insufflation, which shows that the vago,vagal reflex was intact in this preparation. Microinjections of l -glutamate (12.5 nmol L,1in 25 nL) were made into the DMV from approximately ,,1.5 to +,2.0 mm relative to the obex. Microinjections into the caudal (, 1.5 to +,0.0 mm behind obex) and intermediate (+ 0.1 to +,1.0 mm rostral to obex) DMV both significantly decreased LOS pressure, and complete LOS relaxation was noted in 28/32 and 11/18 cases, respectively. LOS relaxation responses to DMV microinjection were highly reproducible and abolished by bilateral vagotomy or hexamethonium (15 mg kg,1intravenously). A nitric oxide synthase inhibitor (l -NAME 100 mg kg,1intramuscularly) significantly increased the time taken to reach the maximal response. Increases in LOS pressure (24 ± 4 mmHg; n = 3) were obtained only when stimulation sites were located equal to greater than 1.5 mm rostral to the obex. LOS relaxation (, 78 ± 10%; n = 6) was evoked by stimulation of the NTS but not immediately outside of the NTS (11 ± 27%; n = 5). We conclude that there is a very extensive population of ,inhibitory' motor neurones in the DMV that may account for the predominant vagal-inhibitory tone in ferrets. As NTS stimulation evokes LOS relaxation and the predominant response to DMV stimulation is also LOS relaxation, this vago,vagal reflex may involve an excitatory interneurone between the NTS and DMV vagal inhibitory output. [source] Chimpanzee responses to researchers in a disturbed forest,farm mosaic at Bulindi, western UgandaAMERICAN JOURNAL OF PRIMATOLOGY, Issue 10 2010Matthew R. McLennan Abstract We describe the behavior of a previously unstudied community of wild chimpanzees during opportunistic encounters with researchers in an unprotected forest,farm mosaic at Bulindi, Uganda. Data were collected during 115 encounters between May 2006 and January 2008. Individual responses were recorded during the first minute of visual contact. The most common responses were "ignore" for arboreal chimpanzees and "monitor" for terrestrial individuals. Chimpanzees rarely responded with "flight". Adult males were seen disproportionately often relative to adult females, and accounted for 90% of individual responses recorded for terrestrial animals. Entire encounters were also categorized based on the predominant response of the chimpanzee party to researcher proximity. The most frequent encounter type was "ignore" (36%), followed by "monitor" (21%), "intimidation" (18%) and "stealthy retreat" (18%). "Intimidation" encounters occurred when chimpanzees were contacted in dense forest where visibility was low, provoking intense alarm and agitation. Adult males occasionally acted together to repel researchers through aggressive mobbing and pursuit. Chimpanzee behavior during encounters reflects the familiar yet frequently agonistic relationship between apes and local people at Bulindi. The chimpanzees are not hunted but experience high levels of harassment from villagers. Human-directed aggression by chimpanzees may represent a strategy to accommodate regular disruptions to foraging effort arising from competitive encounters with people both in and outside forest. Average encounter duration and proportion of encounters categorized as "ignore" increased over time, whereas "intimidation" encounters decreased, indicating some habituation occurred during the study. Ecotourism aimed at promoting tolerance of wildlife through local revenue generation is one possible strategy for conserving great apes on public or private land. However, the data imply that habituating chimpanzees for viewing-based ecotourism in heavily human-dominated landscapes, such as Bulindi, is ill-advised since a loss of fear of humans could lead to increased negative interactions with local people. Am. J. Primatol. Am. J. Primatol. 72:907,918, 2010. © 2010 Wiley-Liss, Inc. [source] An assessment of the immunological status of patients with renal cell carcinoma based on the relative abundance of T-helper 1- and -2 cytokine-producing CD4+ cells in peripheral bloodBJU INTERNATIONAL, Issue 9 2001T. Onishi Objective To assess the immunological status of patients with renal cell carcinoma (RCC), by analysing the proportion of cluster-of-differentiation 4-positive (CD4+) cells showing intracellular cytokine production, i.e. interferon-, derived from T-helper (Th) 1 and interleukin-4 derived from Th2 cells, among peripheral blood lymphocytes from these patients Patients, subjects and methods Peripheral blood samples (5 mL) were collected from 36 patients (mean age 61 years, range 44,78) with RCC before and after they underwent nephrectomy. The proportion of cytokine-producing CD4+ cells was determined by flow cytometric analysis after stimulating the cells with phorbol 12-myristate 13-acetate, ionomycin and brefeldin A, and staining the cells with fluorescein isothiocyanate-labelled anti-interferon-,, anti-interleukin-4 and anti-immunoglubulin-2b antibodies. The results were expressed as the percentage of cytokine-producing cells in the CD4+ population. As a control, peripheral blood obtained from 35 healthy volunteers (mean age 34 years, range 22,49) was also analysed. Results The proportion of CD4+ cells producing interferon-, and interleukin-4 was significantly higher (P < 0.04 and P < 0.001, respectively) in patients with RCC than in controls. The Th1/Th2 ratio (i.e. the ratio of CD4+ cells producing each cytokine) was significantly lower in patients with RCC (P < 0.001). There was a significant correlation in the controls between interferon-, and interleukin-4 production (r = 0.489, P < 0.01) but not in patients with RCC. The proportion of CD4+ cells producing interleukin-4 was significantly higher and the Th1/Th2 ratio significantly lower in patients with high-stage than in those with low-stage RCC (P < 0.05). The percentage of CD4+ cells producing interleukin-4 was significantly less after nephrectomy in those with low-stage RCC (P < 0.01) and the Th1/Th2 ratio significantly greater (P < 0.05) than before nephrectomy; there was no such trend in patients with high-stage RCC. Conclusion An evaluation of the production of interferon-, and interleukin-4 in CD4+ peripheral blood lymphocytes is useful for assessing the immunological status of patients with RCC; there is a change in the predominant response from Th1 to Th2 with increasing stage of RCC. [source] | ||||||||||