[The influence of corvitin on secretory processes and blood flow in the rat gastric mucosa]

We studied parameters of gastric secretion in pylorus-ligated rat and blood flow in the rat gastric mucosa under the influence of drug corvitin used intragastrically in doses of 2.5 and 5 mg/kg. Biochemical analysis of gastric juice was based on the determination of pH, total hydrochloric acid production and total protein, hexosamine and cysteine concentration. Gastric juice analysis in control rats found the presence of hexosamines-- a gastric mucus indicators and cysteine--free amino acid whith properties of a strong antioxidant. Concentration of these compounds in the gastric juice increased as a consequence of corvitin action. However, corvitin did not affect at these parameters of gastric secretion as the volume of gastric juice, pH, hydrochloric acid output rate, protein concentration. Additionally it was shown that corvitin in dose-dependent manner increased blood flow in the gastric mucosa. This results give reason to believe that corvitin can be considered as a tool that amplifies gastric mucosal defense mechanisms without affecting the secretion of gastric hydrochloric acid and total protein.

Pyloric valve transposition as substitute for a colostomy in humans: a preliminary report

BACKGROUND

The purpose of this article was to show that a transposed pyloric valve (PV) can be mobilized to the perianal region and can function as a replacement for an excised rectal sphincter. Surgical research on animals has shown that a vascularized PV can be taken out of gastroduodenal continuity, transposed to the pelvic region with maintenance of fecal control when positioned in the anal area.

METHODS

The surgical procedure has recently proved successful in humans in which the distal end of the left colon was anastomosed to the proximal end of the transposed PV with the distal end of the PV sutured to the skin in the perianal area as the replacement for an excised rectal sphincter. Fecal control was established after the operation.

RESULTS

The PV healed in an anal position in humans with no apparent anatomic or physiological reasons to suggest that the operation might not be successful in the future as a substitute for a surgically excised or a severely damaged rectal sphincter.

CONCLUSIONS

A vascularized PV supplied by the gastroepiploic artery within an omental pedicle can serve as a replacement for an excised rectal sphincter, thus eliminating the need for a permanent colostomy.

Moderate hypothermia induces a preferential increase in pancreatic islet blood flow in anesthetized rats

The aim of the study was to characterize the effects of induced moderate hypothermia on splanchnic blood flow, with particular reference to that of the pancreas and the islets of Langerhans. We also investigated how interference with the autonomic nervous system at different levels influenced the blood perfusion during hypothermia. For this purpose, hypothermia (body temperature of 28°C) was induced by external cooling, whereas normothermic (37.5°C) anesthetized Sprague-Dawley rats were used as controls. Some rats were pretreated with either propranolol, yohimbine, atropine, hexamethonium, or a bilateral abdominal vagotomy. Our findings suggest that moderate hypothermia elicits complex, organ-specific circulatory changes, with increased perfusion noted in the pylorus, as well as the whole pancreas and the pancreatic islets. The pancreatic islets maintain their high blood perfusion through mechanisms involving both sympathetic and parasympathetic mediators, whereas the increased pyloric blood flow is mediated through parasympathetic mechanisms. Renal blood flow was decreased, and this can be prevented by ganglionic blockade and is also influenced by β-adrenoceptors.

Hypertrophic pyloric stenosis in infants: US evaluation of vascularity of the pyloric canal

PURPOSE

To determine if there is increased flow to the pylorus in infants with hypertrophic pyloric stenosis (HPS) and, if so, whether the flow is localized to the muscle layer, mucosal layer, or both.

MATERIALS AND METHODS

Seventy-five infants examined for clinical suspicion of HPS were prospectively recruited for the study. Color scale was standardized at 4.2-4.4 cm/sec. Color Doppler flow at ultrasonography (US) was graded as follows: Grade 1 meant no signal; grade 2, two to five flow signals; and grade 3, extensive or continuous flow. Flow to the muscle or mucosal layer was documented and confirmed with spectral analysis. Infants without HPS served as control patients. Descriptive analyses were conducted to assess the demographic data and US results. Significance was assessed with chi2 or t tests. P <.05 was considered to indicate a significant difference.

RESULTS

HPS was present in 41 infants with a mean age of 5 weeks +/- 2.0 (SD). Their mean flow grade was 2.80 +/- 0.4 in muscle and 2.88 +/- 0.4 in mucosa. HPS was not present in 34 infants with a mean age of 5.9 weeks +/- 4.5. Their mean flow grade was 1.26 +/- 0.5 in muscle and 1.15 +/- 0.5 in mucosa (P <.001). There was no significant difference in flow grades when the dimensions of the pyloric muscle and mucosa were compared. There was no significant difference in age between the HPS and control patient groups.

CONCLUSION

Increased flow accompanies and may conceivably represent an integral component of the changes that occur with infantile HPS.

Diagnosis of angiodysplasia on the caudal aspect of the pylorus: need for side-viewing endoscopy

Recurrent gastrointestinal bleeding in patients with upper gastrointestinal angiodysplasia is common after treatment. This probably is related to the difficulty identifying all the lesions because they frequently are multiple and can be located in areas not easily visualized with forward-viewing endoscopy. We report two cases of patients with gastrointestinal bleeding in whom angiodysplasia as found at surgical enteroscopy on the caudal aspect of the pylorus that could not be identified with forward-viewing endoscopy. The lesions were ablated at the time of surgery or subsequently after location with side-viewing endoscopy, and no further bleeding occurred.

On the mechanisms underlying histamine induction of gastric mucosal lesions in rats with partial gastric vascular occlusion

Although it is well known that histamine induces gastric mucosal lesions in laboratory animals, the fundamental mechanisms remain unclear. In order to further analyze the vascular mechanisms underlying histamine-induced lesions, a new model was developed in the glandular stomach via administration of histamine (40 mg/kg, s.c.) twice to rats with partial gastric vascular occlusion (ligated left gastric artery and vein) also subjected to pylorus ligation. Both antagonists of histamine H(2)-receptors (roxatidine and famotidine) and H(1)-receptors (epinastine and tripelennamine) significantly inhibited lesion formation at doses that did not inhibit acid secretion. Combined treatment of tripelennamine and famotidine synergistically inhibited lesion formation. Nitro L-arginine methyl ester inhibited lesion development; inhibition was reversed by concomitantly administered L-arginine. Indomethacin, diclofenac, and SC-560 (a selective COX-1 inhibitor), but not rofecoxib (a selective COX-2 inhibitor), significantly inhibited lesion formation. In addition, sodium bicarbonate, pirenzepine, S-0509 (a gastrin/CCK(2) inhibitor), omeprazole, sucralfate, and a prostaglandin analog also significantly inhibited lesion formation. It was concluded that the mechanism by which histamine induces gastric lesions in rats with partial gastric vascular occlusion appears to involve extensive vasodilation resulting from histamine acting on microvasculature histamine H(1)- and H(2)-receptors, generation of endogenous nitric oxide and prostaglandins, with the presence of gastric acid.

Pylorus-preserving gastrectomy with radical lymph node dissection based on anatomical variations of the infrapyloric artery

We devised a method for performing pylorus-preserving gastrectomy (PPG) with radical lymph node dissection without compromising pyloric blood flow, based on vascular anatomical evaluation of 210 celiac angiograms. The origin of the infrapyloric artery was variable, but consistently supplied blood flow to the pylorus and the posterior wall of the antrum. When the infrapyloric artery originated from the gastroduodenal artery or from one of its pancreatic branches (type A, 88%), the right gastroepiploic artery was divided at its origin, allowing the excision of all adjacent lymph nodes. When the infrapyloric artery originated from the right gastroepiploic artery (type B, 12%), the right gastroepiploic artery was divided distal to the infrapyloric artery origin and the short right gastroepiploic artery remnant was skeletonized of lymph nodes. We have used this technique to perform PPG on 25 patients with early gastric cancer in the middle third of the stomach with minimal morbidity and no mortality.

The infrapyloric artery and cephalic pancreatoduodenectomy with pylorus preservation: preliminary study

Cephalic pancreatoduodenectomy (CPD) with pylorus preservation has been suggested to improve the functional and nutritional result of surgery. At operation, the first two centimeters of the duodenum are preserved, the vascular arch of the lesser gastric curvature is saved and the right gastroepiploic artery is resected at its origin. The aim of this study on 15 fresh cadavers was to determine the origin of the vascularization of the remaining duodenum and also the possibilities of preserving an optimal vascularization after CPD and pylorus preservation. All of the arteries supplying the remaining duodenum and arising either from the right gastric artery or the right gastroepiploic artery were identified. The distances between the origin of the infrapyloric artery and the termination of the gastroduodenal artery on the cranial and ventral pancreaticoduodenal artery and the left gastroepiploic artery were measured. At CPD with pylorus preservation, the study demonstrated that: 1) the cranial side of the remaining duodenum remains vascularized in 80% of the cases by one or two supraduodenal branches coming from the right gastric artery; 2) ligation of the right gastroepiploic artery eliminates all vascular supply to the caudal side of the remaining duodenum in almost half of the cases; 3) in these cases, the dissection of the bifurcation of the gastroduodenal artery and the vascular section beyond the origin of the infrapyloric artery allowed a direct vascular supply to the remaining duodenum to be preserved.

Autotransplantation of the pylorus sphincter at the terminal abdominal colostomy. Experimental study in dogs

A method for constructing a continent colostomy has been tried in dogs. The pylorus sphincter with blood supply by the left gastroepiploic vessels was transposed around or anastomosed to the terminal abdominal colostomy in five dogs. One dog had a colostomy without pylorus transplantation. Evaluation was by clinical (consistency and weight of fecal material and number of defecations per day), radiologic, and manometry studies. There was no difference in the clinical data. In all the dogs, the radiologic study demonstrated emptying of the contrast medium to the peristomal skin. By manometry one high-pressure zone was demonstrated, and, in all dogs with a transposed or anastomosed pyloric segment, the average resting pressure was superior to that of the control dog. However, the transposed pylorus sphincter alone was not sufficient to control continence.

Bombesin-like immunoreactive material in the gut, and the effect of bombesin on the stomach circulatory system of an elasmobranch fish, Squalus acanthias

The distribution, nature and amount of bombesin-like immunoreactivity (IR) in the gastrointestinal canal and its afferent vessels was investigated in the spiny dogfish (Squalus acanthias) together with the in vitro effect of synthetic bombesin on perfusion flow through the vascularly perfused dogfish stomach. Nerve fibres showing bombesin-like IR frequently occurred in the walls of the anterior mesenteric and coeliac arteries and the intrinsic vessels of the gut. Chromatographic studies revealed that multiple peaks of bombesin-like IR material were present in extracts of the spiny dogfish gastrointestinal vessels. Bombesin-like IR was also present in muscle and mucosal layers of the gut with higher levels in muscle compared with mucosa, and higher levels in the stomach than in the intestine and the rectum. Exogenous bombesin increased the flow through the vasculary perfused spiny dogfish stomach in a dose-dependent manner. Studies with tetrodotoxin and atropine showed that bombesin probably exerts its effect directly on the vascular musculature. It is concluded from this study that bombesin-like material is present in nerves innervating the gut circulatory system of the spiny dogfish. Bombesin may affect the blood-flow to the gastrointestinal canal, possibly via a direct effect on vascular smooth muscle.

[Microvascular changes in the pyloric ring and duodenal invasion in carcinoma of the gastric antrum]

In this study, vascular perfusion of surgically removed specimen was carried out in 45 middle or late staged gastric antrum carcinomas and 5 gastric ulcers to observe the morphology of the microvasculature at the juncture of the stomach and the duodenum. It was found that: 1) The microvasculature on both side of the pylorus and the duodenum communicated through small arteriole and the morphology of the microvasculature varied with tumor-infiltrated depth. 2) The duodenum was found to be invaded by the tumor in only 2 cases in which the tumor was within 1.5 cm from the pyloric ring. 3) The mechanism by which the tumor invaded the duodenum was most likely resulted from direct extension through the interstitium when the microvasculature, the physiological and anatomical intact of the pyloric ring were destroyed by the tumor. 4) Based on the aforementioned observations, the authors propose that in gastric antrum carcinoma, the safe resection length of the duodenum is less than 3 cm when the tumor is 1.5 cm away from the pyloric ring, otherwise, more than 3 cm of the duodenum should be removed.

Thromboxane A2 antagonistic action of a new anti-ulcer agent, azuletil sodium (KT1-32)

The TXA2/PGH2 receptor antagonistic activity of azuletil sodium (KT1-32), a new anti-ulcer agent, was examined. KT1-32 competitively antagonized the contraction of canine gastric arteries induced by U-46619, PGF2 alpha, and PGE2, whereas it had no effect on the PGF2 alpha-, PGE2- and LTD4-induced contraction of guinea-pig ileum, which was not affected by U-46619. In anesthetized dogs, KT1-32 significantly reduced the U-46619-induced decrease in gastric arterial blood flow. Gastric contraction induced by U-46619 in anesthetized rats was markedly inhibited by KT1-32. KT1-32 showed no influence on TXA2 synthetase and cyclooxygenase activities. These results indicate that KT1-32 is a competitive TXA2/PGH2 receptor antagonist, which may be important as to the effectiveness of KT1-32 against gastric ulcer.

The parabiliary venous system

The parabiliary venous system originates from the pancreatico-duodenal and pyloro-duodenal veins, runs along the common bile-duct and the hepatic artery, and divides in the liver hilum into a venous network within the hilar plate. Embryologically, this system, apparently independent of the portal vein, develops together with the bile-ducts and the hepatic artery: these three structures are within the substance of the vasculo-biliary sheaths, and the whole complex invades the liver well after the distribution of the portal vein has been established. It should be pointed out that segments I and IV also appear rather late. Seventy-four specimens with injection of the system have been studied. The hilar plexus sends branches to the veins of the segments adjacent to the hilum. Some vessels directly supply the inferior surface of the quadrate lobe or the caudate lobe, or the left lobe. In 46.50% of specimens, part of the cystic veins are anastomosed with the parabiliary system.

Patterns of blood supply to the gastric mucosa. A comparative study revealing an end-artery model

The form of the gastric arterial supply to the mucosa has been studied in dog, swine, ferret, cat, guinea-pig, rabbit and rhesus monkey. In all these species, the bore of vessels in the submucous plexus diminished from body to pylorus, though this was most marked in the guinea-pig and rabbit. The plexus was also continuous across the pylorus with duodenal vessels. Thus the well known poverty of vascularity in distal parts of the human stomach is shared by other species and is unlikely to be a contributory factor to the initiation of peptic ulcer, a disease limited to man. In dog, swine, ferret and cat, as in man, the primary (largest) and secondary (smaller) components of the plexus lay entirely in the submucosa. In the cat, there was a secondary plexus of much smaller vessels deep to the muscularis mucosae. In the guinea-pig, rat, rabbit and monkey, both plexuses were mostly embedded within the muscularis mucosae. As a result, mucosal arteries had two modes of origin: (a) the first, in which they did not pass through the muscularis mucosae as exemplified in the cat, and (b) the second, where they did pass through muscularis mucosae as exemplified by the dog, ferret and swine; in other species, they passed through part of the muscularis mucosae. Areas of mucosa supplied by a single mucosal artery were measured, and ranged widely from the smallest in the cat to the largest in the dog. These features do not seem to have been reported previously, and may be associated with as yet undiscovered functional mechanisms of the muscularis mucosae. Mucosal arteries of extramural origin were found to occur occasionally in the guinea-pig and rabbit, and hence these may provide an experimental model of the pattern existing in man.

Pyloric preservation with the Whipple procedure

The pylorus-preserving pancreatoduodenectomy simplifies resection, allows a satisfactory postoperative weight gain, prevents postgastrectomy symptoms, is followed by a low rate of jejunal ulceration, and can be performed with an extremely low postoperative mortality rate, providing that the pancreatic and biliary anastomoses are constructed so that no leakage occurs. Preliminary data indicate a satisfactory survival rate when this procedure is used for periampullary cancer, and reasonable relief of pain is achieved when the procedure is used in chronic pancreatitis.

Normal anatomy of the pyloric branch and its diagnostic significance in angiography

The course of the pyloric branch, usually arising from the distal end of the gastroduodenal artery, was investigated using angiography of 15 specimens and of 200 patients. It was found that the pyloric branch usually supplies the greater curvature of the gastric antrum and of the duodenal bulb, pylorus and the oral portion of the descending duodenum, although there may be some variations. A correct diagnosis of the primary site and extent of a malignant tumor in the gastric antrum, duodenum or pancreatic head, needs a thorough knowledge of the normal anatomy of the pyloric branch.

Gross anatomy of the arterial supply of the stomach of the North American beaver (Castor canadensis)

The arterial pattern of the stomach of the North American beaver is studied by dissection of height specimens. The arrangement of the arteries resembles the typical mammalian pattern, although some variations are described. For example, the celiac artery gives off two large vessels, the cardiac and fundic arteries, which supply the corresponding regions of the stomach. Also, the right gastric artery originates from the gastroduodenal vessel instead of the hepatic artery.

[Microangioarchitectonics and microtopography of the blood vessels of the human stomach]

The data of previous investigations on general principles of microarchitectonics of the human intraorganic gastric vessels have been checked. Peculiarities of branching and course of the stomach intraorganic vessels, arterio-venous anastomoses, twisted arterioles, sinusoid venules and veins confirm activity and variability of the organ's circulation at microcirculatory level. Certain slight differences in diameters and number of microvessels have been revealed in some anatomical parts of the serous membrane and submucous layer of the stomach. Maximal differences in vessel diameters of the microcirculatory bed and in number of capillaries per 1 mm2 have been revealed in the most active layers of the gastric wall--in muscular and mucous membranes. In the muscular membrane, large vessels and greater number of capillaries have been revealed in the area of the greater curvature and the pylorus. In the serous membrane in the pyloric area and in the area of the smaller curvature, microvessels have smaller diameters and the number of capillaries per square unit is less.

Studies on metabolism of trazodone. IV. Intestinal absorption in rats and rabbits

The absorption rates are the same in rats and rabbits when [14C]trazodone HCl is injected into the duodenum of animals with pyloric vein cannulation. 2. The absorption of trazodone from the duodenum of rats is rapid in comparison with that of imipramine. 3. The residual food content of the rabbit stomach after fasting delay the overall rate of trazodone absorption by markedly decreasing transit rate from the stomach to the small intestine.

Visceral blood flow distribution during exercise to exhaustion in conscious dogs

We measured changes in organ blood flow (OBF) distribution and systemic hemodynamics in 9 dogs running 5-13 km/h during steady-state (SS) and exhaustive (EE) exercise on a treadmill at 8-15% grade for an average of 35 min. SS was defined when a heart rate (HR) of 80% maximum was attained and when HR was constant for 5-8 min. EE was defined as when the dog collapsed, unable to run longer. We measured heart rate, mean aortic pressure, cardiac output, and stroke volume via implanted probes and catheters. All hemodynamic parameters rose significantly (P less than 0.05) with exercise. Stroke volume and aortic pressure did not rise above SS levels during EE. OBF, determined with microspheres, to the liver, stomach, and intestines declined during SS and returned to control levels during EE. OBF to the kidneys and pancreas was not significantly changed by either SS or EE. OBF to the spleen declined progressively with SS and EE. We concluded that 1) the effect of exercise on OBF depends on the severity of exercise, emphasizing the need to quantify work loads in exercise studies, and 2) the splanchnic organs do not respond homogeneously to exercise and that this response is not adequately described by % of CO assessments.

Observations on the submucous plexus and mucosal arteries of the dog's stomach and first part of the duodenum

Arteriolar patterns of the submucous plexus were studied in all areas of the dog's stomach and in the first inch of the duodenum. There appeared to be no poverty of plexus, although in some cases the vessels were somewhat smaller in the pyloric part of the lesser curvature than elsewhere. Mucosal arteries arose from the plexus, and none appeared to have an extramural origin. In man, on the other hand, there is a poverty of the submucous plexus in the 'ulcer region', i.e. in the incisural region of the lesser curvature and in the first inch of the duodenum, associated in some cases with mucosal end arteries of extramural origin. The absence of these features in the dog, which does not suffer from spontaneous chronic ulceration, lends further support to the view that they play a role in the aetiology of the disease in man.

Blood supply to the human gastroduodenal mucosa with special reference to the ulcer-bearing areas

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