Focal gastric mucosal blood flow as measured by the hydrogen gas clearance method was compared with total gastric blood flow as determined by venous outflow in an isolated segment of canine stomach ...before, during, and after exposure to aspirin. Despite an increase in total gastric blood flow from 10.8 +/- 1.6 ml/min per chamber to 17.4 +/- 1.9 ml/min per chamber and mucosal blood flow at nonulcerated sites from 29.5 +/- 4.3 ml/min per 100 g to 83 +/- 14.4 ml/min per 100 g, mucosal blood flow at the site of aspirin-induced ulceration was significantly reduced from 29.5 +/- 4.3 ml/min per 100 g to 12.5 +/- 2.5 ml/min per 100 g. After the removal of aspirin, mucosal blood flow returned to control levels. Such a redistribution of mucosal blood flow in response to aspirin is consistent with the localized nature of acute aspirin-induced injury. The findings also explain the inability of previous methods measuring blood flow of the entire stomach to demonstrate mucosal ischemia during such injury.
We assessed the interaction between the APOE ε4 allele and education level in the etiology of Alzheimer's disease (AD) among memory clinic patients from the multicenter DESCRIPA study. Subjects (n = ...544) were followed for 1 to 5 years. We used Cox's stratified survival modeling, adjusted for age, gender, and center. APOE ε4 predicted the onset of AD-type dementia in middle (HR 3.45 95% CI 1.79-6.65, n = 222) and high (HR 3.67 95% CI 1.36-9.89, n = 139) but not in low educated subjects (HR 0.81, 95% CI 0.38-1.72, n = 183). This suggests that mechanisms in developing Alzheimer-type dementia may differ between educational groups that raises questions related to Alzheimer-type dementia prevention.
Gastric mucosal blood flow as measured by the hydrogen gas clearance method was compared with total gastric blood flow as determined by venous outflow in an isolated segment of canine stomach. During ...rest and histamine stimulation, hydrogen gas clearance correlated lineally with total gastric blood flow (p less than 0.001). Correlation analysis revealed a slope of 1.21 and a correlation coefficient of 0.97. The slope of 1.21 indicates that the ratio of mucosal to total gastric blood flow was approximately 82 percent. This fractional distribution of blood flow is in agreement with that previously reported by microsphere technique. In the intact stomach of anesthetized rats and dogs, antral mucosal blood flow was significantly higher than that of the corpus. This finding may, in part, contribute to the observation that acute stress erosion occurs predominantly in the corpus of the stomach. Histamine stimulation selectively increased the mucosal blood flow of the corpus, whereas antral mucosal blood flow remained unchanged. As a result, there was no significant difference in mucosal blood flow between the antrum and the corpus during histamine stimulation.
St. Louis children's Aquarium was founded as a not-for-profit organisation in 1971. In 1989, it organised its heretofore egalitarian efforts to build an aqarium and provide education, research and ...conservation programming as a response to an assessment based identified need in the community. This instrument pointed to various instructional needs from pre-K to graduate level, from hands-on learning to library resources to actual research and professional opportunities to instruct the various publics involved in the aquatic sciences. By 1993, over 300,000 people were served directly through outreach educational activities, and decisively, research practices were devised to apply scientific to efforts to solving real environment issues.
The effects of cimetidine inhibition of acid secretion on gastric mucosal blood flow and the intramural pH of gastric mucosa were assessed in a canine model ex vivo. Intravenous infusion of histamine ...at 1.0 microgram/kg per minute resulted in brisk acid secretion, which was associated with an increase in total gastric and mucosal blood flow and the intramural pH of gastric mucosa. The increased blood flow and mucosal alkalinity may be compensatory mechanisms of the stomach to enhance its tolerance of luminal acid. Cimetidine inhibition of acid secretion was associated with a reduction in mucosal alkalinity and total gastric and mucosal blood flow. These adverse effects of cimetidine on blood flow and mucosal pH, two important factors in the stomach's self-defense against acid injury, may explain the inefficacy of cimetidine in the prevention of stress ulcers.
The influence of intraarterial infusion of hydrochloric acid on gastric mucosal injury induced by topical bile salts was assessed in a canine ex vivo model. Exposure of the gastric mucosa to 5.0 mM ...sodium taurocholate in acid bathing solution alone resulted in a slight but not significant reduction in intramural pH of gastric mucosa and mild mucosal damage. When hydrochloric acid (0.1 N) was infused directly into the artery perfusing the stomach of the dogs, the intramural pH of gastric mucosa markedly decreased. The mucosal acidification was associated with severe ulcers in all test dogs that received intraarterial infusion of hydrochloric acid. The deleterious effect of intraarterial infusion of hydrochloric acid was not due to ischemia since the gastric blood flow remained relatively unchanged. The severe mucosal ulcerations were perhaps caused by the decrease in the ability of gastric blood to buffer the incoming luminal acid induced by topical bile salts. These results suggest that (1) the pH of arterial blood perfusing the stomach may also be an important determinant in the ability of the gastric mucosa to protect itself against acid injury, and (2) better management of systemic acid-base balance may contribute to a lower incidence of stress ulcers in critically ill patients.
Comput.Phys.Commun. 148 (2002) 87-102 This is the manual of the specialized event generator TopReX 3.25. The
generator provides the simulation of several important processes in pp and p
pbar ...collisions, not implemented in PYTHIA (yet). Some of these processes
include t-quarks whose spin polarizations are taken into account in the
subsequent decay of the t-quarks. Several non-SM top quark decay channels are
included, too. All calculated subprocesses can be accessed from PYTHIA as
external processes. In addition, TopReX can be used as stand alone event
generator, providing partonic final states before showering. In this mode the
control of the event generation is taken by TopReX itself. A few simple
examples of main routines, which show how to use TopReX in the different modes
are discussed.
This is the manual of the specialized event generator TopReX 3.25. The generator provides the simulation of several important processes in pp and p pbar collisions, not implemented in PYTHIA (yet). ...Some of these processes include t-quarks whose spin polarizations are taken into account in the subsequent decay of the t-quarks. Several non-SM top quark decay channels are included, too. All calculated subprocesses can be accessed from PYTHIA as external processes. In addition, TopReX can be used as stand alone event generator, providing partonic final states before showering. In this mode the control of the event generation is taken by TopReX itself. A few simple examples of main routines, which show how to use TopReX in the different modes are discussed.
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