The effects of intraarterial administration of somatostatin upon intestinal blood flow, intestinal capillary surface area, oxygen consumption and intestinal motor activity were measured in anesthetized dogs. Blood flow to the segment of distal ileum was measured with an electromagnetic blood flow meter, and arteriovenous oxygen difference (AVO2) was determined spectrophotometrically. ...

Changes in blood flow in the celiac artery, superior mesenteric artery, and pancreas in response to an intravenous injection of synthetic human gastric inhibitory polypeptide (GIP) were determined simultaneously and continuously in anesthetized dogs, using a transit-time ultrasonic flowmeter and a laser-Doppler flowmeter. Injection of GIP significantly increased superior mesenteric ...

The purpose of the present study was to determine the effects of lethal intravenous infusions of Staphylococcus aureus (SA) in adult dogs. Animals were maintained under anesthesia for 6 hr and observed until death following the 1-hr infusions of SA organisms. Findings unique to SA administration compared to those with ...

Recent studies indicate that the mucosal circulation of the small intestine possesses more potent local circulatory control mechanisms than the muscularis. Several lines of evidence support this assertion: the absence of reactive hyperemia in the muscularis, the confinement of glucose-induced hyperemia to the mucosal circulation, and the more effective autoregulation ...

In this study we investigated the relative vascular response of different locations of the gastrointestinal tract to continuous intravenous infusion of isoproterenol (0.1 microgram kg-1 min-1 for 10 min). The vascular response of some nonsplanchnic organs was also examined. Blood flow of the arteries was measured by electromagnetic flowmetry and ...

Lactulose and neomycin have, besides influencing ammonia production of the intestinal flora, been proposed to reduce glutamine-dependent ammonia formation. To test this hypothesis we determined the effects of lactulose and neomycin on the release or uptake of ammonia, urea, and amino acids across the intestine of freely moving healthy pigs. ...

Interest in the pathogenesis of neonatal necrotizing enterocolitis has prompted study of the intestinal circulation in developing animals. It is conceivable that poorly developed collateral channels may predispose the neonatal intestine to ischemic insults. We therefore characterized intestinal collateral blood flow in anesthetized and ventilated 1-day and 1-month-old piglets. Intestinal ...

The effects of iv injection of ochratoxin A (OA) on its absorption from the jejunum in rats were studied in vivo to demonstrate the jejunal absorption of OA in relation to the OA level in blood plasma. In addition the effects of the pH of the medium on OA uptake ...

The effect of oral pretreatment with indomethacin on the intestinal first-pass metabolism of salicylamide (SAM) was studied in rabbits using in situ intestinal sacs with complete mesenteric venous blood collection. The appearance of both SAM and its metabolites into the mesenteric venous blood was measured directly by cannulating the mesenteric ...

Acute massive intestinal ischemia is an abdominal catastrophe. Prompt diagnosis and restoration of blood flow is essential; otherwise, massive intestinal resection occurs, leading to death or, in the survivors, intestinal cripples. In this study, the time of warm reversible ischemia in the canine intestine was explored. After this time was ...

Substance P (SP), a putative mediator of neurogenic inflammation, has previously been shown to induce plasma extravasation when exogenously perfused over a blister base induced on the rat hind foot pad. Using the same animal model, we have studied the role of vasoactive intestinal polypeptide (VIP), one of the neuromodulators ...

Because clinical assessment of bowel viability is unreliable, other methods of determining intestinal perfusion have been recommended. Since none of these quantifies intestinal blood flow, we measured flow at the detection thresholds of Doppler ultrasound, photoplethysmography, and intravenously administered fluorescein, perfused the intestines at these threshold levels, and assessed histologic ...

Using isolated autoperfused intestinal segments, the effects of flunixin meglumine administration on systemic arterial blood pressure, jejunal blood flow, vascular resistance, motility, arteriovenous oxygen difference, and oxygen consumption were determined in 10 anesthetized ponies ventilated with a mixture of halothane and oxygen. Saline solution or flunixin meglumine (1.1 mg/kg of ...

Because cardiac output decreases after burn injuries, investigators have assumed, based upon dye clearance techniques, that hepatic and intestinal blood flow are also decreased following these injuries. Blood flow to the liver, stomach, small intestine, and kidney was determined by the uptake of 201thallium and 125I-labeled fatty acid (para-125I-phenyl-3-methyl pentanoic ...

We have determined the most suitable method for the automated analysis of the clotting parameters in sheep intestinal and prefemoral lymph as defined by the Activated Partial Thromboplastin Times (APTT; measure of intrinsic coagulation pathway) and the Prothrombin Times (PT; measure of extrinsic coagulation pathway). As opposed to optical density ...

Differences in O2 delivery and consumption along the fed and fasted small intestine are described. Total wall blood flow was determined in sequential segments of small intestine from 5 to 6-month-old male, anesthetized Fischer 344 rats either 75-80 min before or after feeding, using radioactive microspheres. Oxygen saturation in submucosal ...

Studies in intact animals have shown that intestinal solute absorption may be enhanced with increasing intraluminal volume and flow rate, perhaps because of increases in functional absorptive surface area or perturbation of unstirred layers. We used single-pass perfusions of rat ileum, performed by simultaneously infusing and withdrawing at equal rates, ...

Stimulation of sympathetic fibers or infusion of norepinephrine (NE) into the superior mesenteric artery (SMA) leads to an initial decrease in intestinal blood flow, which is followed by a return of flow toward the base-line value (autoregulatory escape) despite continued nerve stimulation or NE infusion. Although the mechanisms responsible for ...

In-vitro simultaneous luminal and vascular perfusion using the perfluorochemical emulsion, FC-43 emulsion, as a vascular perfusate, was examined for drug absorption in rat jejunum. The intestinal membrane in this system was found to retain its normal barrier functions for drug transport, as evident from the following: (i) stable absorption clearance ...

The effects of intra-arterial administration of leukotrienes (LT) C4 and D4 upon total intestinal and mucosal blood flow, intestinal oxygen consumption and motor activity were measured in anesthetized dogs. Blood flow to a segment of distal ileum was measured with an electromagnetic blood flow meter, and arteriovenous oxygen difference (AVO2) ...

The effects of vasoactive intestinal peptide (VIP) and related structural homologues on tissue vascular conductances were investigated in anesthetized male rats. VIP, peptide histidine isoleucine (PHI), secretin, growth hormone-releasing factor (GHRF), gastric inhibitory peptide (GIP), or saline was infused intravenously over 4 min. Tissue blood flows were measured during this ...

Formyl-methionyl-leucyl-phenylalanine (FMLP), a peptide released from bacteria in the gut lumen, is known to both attract and activate neutrophils. The aim of this study was to determine whether luminal perfusion with 1 microM FMLP alters microvascular permeability, blood flow, and neutrophil migration in the small intestine of control rats and ...

Human cervical tissue specimens were excised after hysterectomy at various phases of the menstrual cycle (n = 12), and small intracervical arteries were dissected free by microtechnique. Ring preparations of the vessels were prepared and mounted in organ baths, and isometric circular tension was recorded. Norepinephrine, 3 X 10(-8) to ...

The possible role of histamine or adenosine in intestinal blood flow autoregulation in 1-mo-old swine was examined by obtaining pressure-flow relationships before and during intestinal histamine H1- or adenosine-receptor blockade in two groups of fasting animals under anesthesia with pentobarbital sodium (30 mg/kg). Changes in abdominal and thoracic aortic pressures ...

Using immunohistochemistry at the light and electron microscopic level some blood vessels along the median eminence were shown to be surrounded by dense networks of vasoactive intestinal polypeptide/peptide histidine isoleucine (VIP/PHI)-positive fibers. VIP and PHI released from these fibers may contribute to the elevated levels of these two peptides measured ...

Laser Doppler flowmetry (LDF) was evaluated as a method for study of gastrointestinal blood flow with emphasis on clinical applicability in man. Measuring depth of LDF in the gastrointestinal tract was studied in cat and man. The LD-signal was attenuated in an exponential manner by unperfused intestinal tissue between the ...

The effect of epidural bupivacaine (5 mg/ml) on intestinal blood flow was studied with laser Doppler flowmetry in 15 patients during operations including various types of large bowel resection. In the colon, blood flow increased in 13 out of 15 patients, which was significant at the 1 per cent level. ...

The epithelial cells of the gastrointestinal tract from different species show a very variable expression of blood group active glycosphingolipids. The core saccharide sequences are typical for the species as, for example, type 1 chains (Gal beta 1----3GlcNAc) are found in the small intestine of man, rat, and pig and ...

Accepted methods to evaluate intestinal vascularity intraoperatively include standard clinical criteria (SCC), doppler ultrasound (DUS), and intravenous fluorescein (FLF). A combination of methods is often used to overcome disadvantages of individual techniques. Assessment of intestinal vascularity by FLF was compared to SCC, DUS, and pulse oximetry (POX) in segments of ...

Dissolution and absorption rates (in vitro); clearance from blood and elimination rates of N-nitrosoephedrine (NEP) and N-nitrosopseudophedrine (NPEP) in mice were determined. The two isomers obeyed first-order kinetics and from the slope of the regression line, the rate constant for each study was obtained. These constants were 0.023, 0.038 min-1 ...

An animal model was proposed to clarify the difference in occurrence of enterocolitis in congenital aganglionosis. When gaseous distention of the colon was localized to the rectosigmoid area, enterocolitis never occurred. On the contrary, when it involved the left colon, enterocolitis occurred in 13 of 15 patients. Intestinal blood flow ...

Male broilers (3.0 to 3.4 kg) chronically implanted with an electromagnetic blood flow probe on the celiac artery were used to study the effect of feeding and heat exposure on celiac mean blood flow (MBF). Postprandial celiac MBF and a cyclic pattern of MBF, produced in response to feeding, were ...

Although cholecystokinin-58 (CCK-58) is a major molecular form stored in the intestine, it has not yet been shown to be released into the circulation. This report describes in vitro degradation of CCK-58 in human blood and plasma and the molecular forms detected when this degradation is inhibited. After incubation of ...

Swine (6 per group) were used to study gastrointestinal blood flow during T-2 toxin-induced shock. Low- and high-dose groups were given T-2 toxin at 0.6 or 2.4 mg/kg via the pulmonary artery; controls were given the ethanol vehicle. Radiolabeled microspheres were administered into the left atrium to assess organ blood ...

Nearly three-quarters of patients on long-term treatment with non-steroidal anti-inflammatory drugs (NSAIDs) have small-intestinal inflammation, the consequences of which are largely unknown. Two potentially important complications, blood and protein loss from the small intestine, have been studied. 49 patients on NSAIDs underwent study with an indium-111 labelled leucocyte technique which ...

The human vagina is known to be heavily innervated by vasoactive intestinal polypeptide (VIP) immunoreactive nerve fibres. In the present study we have examined the effect of VIP (900 pmol x kg-1 x h-1, IV during 30 min) on vaginal lubrication and blood flow in fourteen normal non-pregnant women. Vaginal ...

Holstein bull calves, 8 to 12 wk of age, were anesthetized with halothane gas. An approximate 20-cm section of small intestine, 60 to 90 cm proximal to the ileocecal junction was clamped to isolate blood circulation to a single set of arcuate vessels and to form an intestinal segment fitted ...

The effects of intra-arterial administration of substance P upon intestinal blood flow, oxygen consumption, intestinal motor activity, and distribution of blood flow to the compartments of the gut wall were measured in anesthetized dogs. Blood flow to the segment of distal ileum was measured with an electromagnetic blood flow meter ...

The accuracy of the duplex Doppler ultrasound system in the measurement of blood flow in the splenic artery and the superior mesenteric artery was evaluated in seven anesthetized dogs by comparing blood flow recordings obtained simultaneously with the electromagnetic flowmeter, with those obtained with the combination of B-mode and M-mode ...

Total and regional splanchnic blood flows were measured with radiolabeled microspheres (15 micron) in one-kidney, one-clip renal hypertensive rats at 2, 4, and 6 wk after induction of hypertension. Arterial pressures (mean +/- SE, mmHg) for the normotensive rats (N) and age-matched hypertensive rats (H) were 110 +/- 5 and ...

The aim of the study is to determine the effects of selective cardiac receptor unloading on vascular resistance and net fluid transport in the small intestine. In anesthetized cats, cardiac receptors were unloaded by positive pressure ventilation (PPV). Arterial baroreceptor activity was artificially maintained constant. To test if the observed ...

Necrotizing enterocolitis (NEC) is thought to be secondary to mucosal ischemia. Because blood flow to the submucosal plexus is derived from vessels traversing three separate layers of visceral smooth muscle (longitudinal, circular, and muscularis mucosa), we investigated whether an increase in their tone might elicit mucosal ischemia. The intestinal intraluminal ...

The distribution of liposomes within the intravascular space and the extent to which they escape into extravascular space strongly impact on the application of lipid vesicles as a carrier for pharmacologically active agents. The present study investigates how intact small unilamellar vesicles (SUV) may be taken up by different tissues ...

Hyperosmolal feedings have been implicated as a cause of potential disruption to the physiology of the neonatal intestinal tract. To evaluate this we studied eight awake lambs (11 +/- 2 days old) with chronically implanted catheters in the portal sinus, descending aorta, and left and right ventricles. Blood flow (Q) ...

The role of intracortical vasoactive intestinal polypeptide (VIP)-containing neurons in the regulation of cortical blood flow was investigated in rats by immunohistochemical and hydrogen clearance methods. Immunohistochemical studies revealed an intimate association between intracortical VIP-containing neurons and small blood vessels. Intracortical injection of a VIP solution (10(-5) M) produced significantly ...

The aim of this study was to assess the extent of collateral blood flow provided by the celiac and inferior mesenteric arteries to the intestines during total occlusion of the superior mesenteric artery (SMA). In anesthetized cats, blood flow to the pancreas, duodenum, jejunum, ileum, and colon was measured with ...

The origins of historical terms, such as "Arc of Riolan" and "marginal artery of Drummond" are traced herein with emphasis on the inherent confusion caused when these terms are used. Basic mesenteric anatomy is briefly mentioned and pathologic anatomy with its altered direction of blood flow induced by atherosclerosis is ...

Arachidonic acid is metabolized to leukotriene (LT) B4, C4, D4, and E4 by lipoxygenase. LTB4 is a chemotactic agent while LTC4 and LTD4 stimulate smooth muscle fibers to contract. Mesenteric vessels have the capacity to release leukotrienes. The possibility that leukotrienes might be responsible for or contribute to mesenteric ischemia ...

Various diesters of 9-[(1,3-dihydroxy-2-propoxy)-methyl]guanine (DHPG) were screened in order to identify a derivative with improved oral absorption. The solubilities and dissolution rates decreased with increasing chain length and branching of the ester group. However, the dipropionate ester showed an anomalously faster dissolution rate. The rates of hydrolysis to DHPG in ...

The hemodynamic effects of Ro 22-1327 [nat-(15R,16R)-16-fluoro-15-hydroxy-9-oxoprosta-5(Z),1 3(E)-dienoic acid], a prostaglandin E2 analog, were evaluated in anesthetized spontaneously hypertensive rats (SHR). Within 3-4 h of topical application (1 and 3 mg/kg), a dose-dependent decrease in mean arterial blood pressure was observed. At 6 h following drug application, steady-state mean arterial ...