牦牛皱胃组织结构及黏膜免疫相关细胞研究

为揭示牦牛皱胃组织结构和黏膜免疫相关细胞的分布与数量变化的规律,采用组织化学法、图像分析法及透射电镜技术,对牦牛皱胃组织结构及上皮内淋巴细胞、浆细胞和肥大细胞变化进行了研究.结果表明:牦牛皱胃胃壁由黏膜层、黏膜下层、肌层和浆膜构成.皱胃幽门腺区胃小凹深度最深、腺体最长、肌层最厚;3个腺区肌层厚度、腺体长度之间差异极显著(P＜0.01);幽门腺区与胃底腺区、贲门腺区之间胃小凹差异极显著(P＜0.01),胃底腺区与贲门腺区之间差异不显著(P＞0.05).牦牛皱胃黏膜上皮内淋巴细胞数量和浆细胞数量,3个腺区之间差异不显著(P＞0.05);肥大细胞数量以胃底腺区最多,幽门腺区最少,两者之间差异极显著(P＜0.01),贲门腺区与胃底腺区和幽门腺区之间差异不显著(P＞0.05).皱胃各腺区固有层中均有大量的弥散淋巴细胞和孤立淋巴小结.电镜观察表明,胃小凹柱状上皮细胞排列紧密.幽门腺区固有层中有大量的黏液细胞,黏液细胞呈高柱状或锥体状,核位于基底部,在细胞顶端常聚集有较多的电子密度较高的颗粒.胃底腺区和贲门腺区有大量的壁细胞和主细胞.牦牛皱胃的组织结构和其他反刍动物基本相似,但各层有其明显特点.牦牛皱胃各腺区固有层中均有大量弥散淋巴细胞和孤立淋巴小结,使牦牛皱胃具有比其他反刍动物更强的黏膜免疫功能.     

A new method for detecting the abomasal position and characteristics of movement at the onset of the left displacement of the abomasum in cows

A new method has been developed by us to observe the movements of the abomasum by using a magnet and digital magnetometer. Four cows with left displacement of the abomasum underwent conventional correction by rolling without tacking. A doughnut-type magnet was sutured to the pyloric region in a routine operation. The same was done in three control cows. The position of the pyloric region was observed with a digital magnetometer from outside the cow's body. The magnets in the pyloric region of the control cows were located at the right side of the abdominal cavity at 10-30 cm anterior to the udder base, and moved slightly in various directions within the span of a day. On the other hand, the magnets in the pyloric region of cows with abomasal displacement moved widely in the abdominal cavity from the normal right side to the abnormal left front side. A large movement of the magnet from the normal right side to the abnormal left side of the abdominal cavity was observed within 12 h of the onset of abomasal displacement.     

Pyloric obstruction after toggle-pin fixation of left displaced abomasum in a cow

One potential complication of blind abomasopexy techniques, including the toggle-pin technique, is the possibility of creating pyloric outflow obstruction. Cows that have had left displaced abomasum corrected by this method should be observed closely for the first 48 postsurgical hours for signs of deterioration. If pyloric obstruction is suspected and the securing sutures are cut before fibrous adhesions have formed, permanent damage may be minimized.     

An attempt to produce Ostertagia circumcincta infections in Mongolian gerbils

Adult infections of Ostertagia circumcincta were successfully established in gerbils, although worm growth was retarded compared with infections in sheep. Chronic administration of beta-methasone to the host enhanced development of the parasite reproductive system but did not increase infection rate or prevent worm rejection. Infection rates achieved with single infections were not increased by using daily or weekly trickle infection regimes with or without prior exsheathment of larvae. Examination of stomachs from infected gerbils demonstrated pathological changes in the pyloric region which was the predilection site for O. circumcincta. This is in contrast to infections in sheep in which the fundic region of the abomasum is the preferred site.     

Differential immune response between fundic and pyloric abomasal regions upon experimental ovine infection with Haemonchus contortus

The effect of experimental haemonchosis on the number of tissue eosinophils, plasma cells and lymphocyte subpopulations was evaluated in the fundic abomasal region, the pyloric abomasal region and the abomasal lymph node of Blackbelly lambs, which are resistant to infection, and Columbia lambs, which are susceptible to infection. An increase in the number of tissue eosinophils and CD4+ and WC1(+)γδ T-cells was observed in the pyloric abomasal region of Blackbelly lambs and correlated with lower worm burden and greater resistance to infection. Increases in IgA+ plasma cells from the pyloric abomasal region were observed in both infected groups, but there was no difference between the groups. Therefore, increases in IgA+ plasma cells did not explain the resistance observed. Infection caused a significant increase in tissue eosinophils in the abomasal lymph node of Blackbelly lambs and a decrease in the number of CD4+ T-cells in lambs of both breeds. CD8+ T-cells and IgG+ and IgM+ plasma cells were not associated with either infection or resistance. In this work, clear differences were observed in the numbers of CD4+ and WC1(+)γδ T-cells, tissue eosinophils and IgA+ plasma cells between the abomasal regions studied. These differences indicate that the immunological response is not homogenous in all abomasal mucosa and that evaluating the response from a single abomasal region may not be representative of the cellular response across the abomasum.     

Histological studies of the occurrence of organisms shaped like Campylobacter in the abomasum of calves]

The mucosa of the abomasum is a strongly acidic and therefore germ poor, but not entirely germfree environment. Only in isolated areas of the fundic glands zone were straight rods in the foveolas, and even more seldom spiral shaped bacteria could be encountered. They had no relation to the inflammatory infiltrates. On the other hand, Campylobacter-like organisms were more often observed in the pyloric region and, preferably, in a narrow zone following the cutaneous mucosa of the omasum. These organisms appeared to have a different size (1.3 to 2.4 microns length and 0.4 to 0.8 microns width) and they occurred deep inside the glands in an almost pure fashion. Whereas they caused no visible reaction of the tissue in the narrow cardiac zone, their occurrence in the pyloric region was several times connected with neutrophilic-rich infiltration. It ought to be tested, whether Helicobacter are among these Campylobacter-like organisms, which cause a disease leading up to ulcerations in calves similar to gastritis B in humans.     

The Functional Structure of the Pylorus in the Ox

In spite of recent electromyographic experiments and myotomy on the pylorus, a detailed morphological study of that region is still lacking. In this study the pyloric part of the abomasum and the first 15 cm. of the duodenum have been investigated macro- and microscopically in 20 veal calves and 20 adult cattle. The circular muscle layer of the terminal part of the pars pylorica thickens into a proximal and a distal sphincter. Two U-shaped muscle loops, one on the visceral and the other on the parietal surface, are fixed by their base to the sphincter pylori. Together with longitudinal fibers of the abomasum and the duodenum, they may form a dilator pylori. A fibrous septum, which separates the muscular coat of the stomach from that of the duodenum is absent. Some longitudinal fibers of the abomasum are continuous with those of the duodenum. The loose mucosal folds in the pars pylorica and also the torus pyloricus may act as a mucosal plug in closing the pylorus. These findings are discussed in view of possible functional implications.     

Abomasal cannulation in the milk-fed calf using a 7 mm polyurethane tube

The main objective of this study was to develop a simple and effective surgical technique for abomasal cannulation in neonatal calves. General anaesthesia was induced in 12, 3-day-old male dairy calves and a polyurethane cannula surgically implanted in the abomasal body (n = 12) and pyloric antrum (n = 6) through a right paracostal incision. Fifteen cannulae remained in situ from day 3 to 34 of life (mean: 29 days), and three cannulae were extruded 13-14 days after placement. Calves were clinically healthy and gained weight during the study. Cannulae were well tolerated by the calves and abomasal contents did not leak from the cannula sites. Necropsy examination revealed firm adhesions between the abomasum and parietal peritoneum at the cannula sites with no evidence of leakage or peritonitis. We conclude that surgical placement of polyurethane tubes designed for percutaneous endoscopic gastrostomy provided a useful method for cannulation of the abomasum of neonatal calves. The cannulation technique can be used for experimental studies, as well as for nutritional and fluid support of sick calves that cannot be managed by oral treatment.     

The effects of vagotomy on the abomasum in calves: radiography and protein gene product 9.5 immunohistochemistry.

Abomasal disorders of calves with total vagotomy, operated on at 1 week old, were investigated with radiography and protein gene product (PGP) 9.5 immunohistochemistry. Radiographic findings indicated abomasal atony with dilatation in all calves 2 weeks after vagotomy, while 4 weeks after vagotomy abomasal dilatation was detected in 2 calves and another 2 calves showed dilatation and impaction. The densities of PGP 9.5-immunoreactive nerves in the tunica muscularis decreased significantly in the corpus region of the greater curvature 2 weeks after vagotomy and in the pyloric region of the lesser curvature 4 weeks after vagotomy, and it was at its lowest 4 weeks after vagotomy in all regions examined. In conclusion, abomasal dilatation and/or impaction in vagotomized calves confirmed by radiography were related with a decreased frequency of nerves in the tunica muscularis of the abomasum.     

Gastric impaction and obstruction of the small intestine associated with persimmon phytobezoar in a horse

Signs of mild colic, intermittent lethargy, and weight loss of 6 weeks' duration in a 2-year-old Quarter Horse gelding were attributed to persimmon (Diospyros virginiana) phytobezoar formation. Diagnosis of the phytobezoar was facilitated by gastric endoscopy. Signs of gastrointestinal tract obstruction were associated with a large phytobezoar in the lumen of the stomach, gastric ulceration, and obstruction of the small intestine (as a consequence of fragmentation of the primary bezoar). Conservative treatment, using mineral oil and dioctyl sodium sulfosuccinate, was unsuccessful. A celiotomy was performed, and gastric impaction and partial obstruction of the small intestine associated with phytobezoar formation and fragmentation were identified. The horse made a complete recovery following removal of all phytobezoars. Persimmon phytobezoar should be considered in the fall and winter as a possible cause of lethargy, colic, and weight loss in horses allowed access to persimmon fruit.     

Effects of breed, diet and sex on the alkaline phosphatase activity in walls of the bovine rumen and abomasum

Alkaline phosphatase (APase) activity in tissue samples, with adherent bacteria, was measured from two sites in the rumen and from two sites in the abomasum of 57 yearling Angus and Hereford bulls and heifers fed a high or a low energy diet. In the rumen, APase activity was higher at the caudoventral blind sac than at the dorsal sac in animals of both breeds fed the high energy diet and in Angus bulls fed the low energy diet, but the reverse was observed in Hereford bulls fed the low-energy diet (P less than .01). In the abomasum, APase levels were higher for bulls than heifers (P less than .01) and higher at the fundic than at the pyloric region (P less than .01). Morphological studies also showed that rumen samples from animals fed a high energy diet exhibited a more widely distributed APase activity and an increase in the digestive recycling of epithelial cells that produced some "pitting" of the tissue. The higher APase activity of the epithelial tissue of animals fed the high energy diet may be explained by the greater rate of cell death and renewal indicated by the higher mitotic index reported by other researchers who have studied the cell cycle of the rumen epithelium in ruminants fed high and low energy diets.     

Histologic and immunocytochemical study of endocrine cells in the gastrointestinal tract of the cow and calf

The regional distribution and relative frequency of argyrophil cells, and of cells immunoreactive for 5-hydroxytryptamine (5-HT), substance P (SP), somatostatin, glicentin, glucagon, bovine pancreatic polypeptide (BPP), gastrin, leucine-enkephalin, gastric inhibitory polypeptide (GIP), cholecystokinin, secretin, motilin, and neurotensin were studied in 9 segments from the gastrointestinal tract of cows (greater than 1 year old) and calves (less than 3 months old). Argyrophil cells, 5-HT-immunoreactive cells, and somatostatin-immunoreactive cells were distributed throughout the gastrointestinal tract, whereas the other immunoreactive cells were more restricted in distribution. Most endocrine cells were more numerous in the calf than in the cow. This feature was most conspicuous in the abomasum. In the abomasum, argyrophil cells in the cow and calf and 5-HT-immunoreactive cells in the calf were found predominantly in the fundic region, whereas somatostatin-immunoreactive cells and gastrin-immunoreactive cells in the cow and calf and 5-HT-immunoreactive cells in the cow were most numerous in the pyloric region. Substance P-, glucagon-, BPP-, and leucine-enkephalin-immunoreactive cells were rarely detected. In the small intestine, argyrophil cells, 5-HT-, SP-, somatostatin-, gastrin-, GIP-, cholecystokinin-, secretin-, and motilin-immunoreactive cells were most numerous in the duodenum. Neurotensin-, glicentin-, glucagon-, and BPP-immunoreactive cells were detected with the highest frequency in the ileum. In the large intestine, argyrophil cells and 5-HT-, glicentin-, BPP-, somatostatin-, glucagon-, and SP-immunoreactive cells occurred with the highest frequency in the rectum.     

Position of the abomasum in dairy cows during the first six weeks after calving

The position of the abomasum in six cows was examined by ultrasonography at regular intervals for six weeks after they had calved. Its position was established by determining the distance between the margin of the left side of the abomasum and the ventral midline at two sites. During the last weeks of pregnancy, the abomasum was positioned in a small region of the left ventral side of the abdominal cavity. At parturition it was positioned high on the left side and then descended. The abomasum was furthest from the midline immediately after parturition. Its position was related to the interval after calving, the cow's feed intake, and the pH and osmotic pressure of the rumen fluid. There was considerable variation between the cows in the position of the abomasum, which was in part due to analytical variation, and in individual cows it had a circadian rhythm.     

Use of a carbonated beverage to disintegrate a phytobezoar obstructing the intrathoracic portion of the oesophagus of a horse

This report describes the treatment of a 17-year-old American Quarter Horse gelding for an oesophageal obstruction of approximately 24 h’ duration. An intraluminal oesophageal mass resembling a phytobezoar and located close to the cardia, was observed during endoscopic examination of the oesophagus of a horse showing signs of oesophageal obstruction. An intrathoracic oesophageal diverticulum, filled with fluid, was observed about 40 cm proximal to the obstruction. The end of a nasogastric tube was guided beyond the diverticulum, using gastroscopic observation, so that its tip rested close to the obstruction. The obstruction failed to disintegrate or move into the stomach despite vigorous, prolonged lavage. With the nasogastric tube left in place, and the horse's head elevated, 0.5 L cola was administered adjacent to the obstruction through the nasogastric tube. The head was maintained in the elevated position for an hour, after which time the head was lowered and oesophageal lavage resumed. The nasogastric tube was passed into the stomach within 3 min of re-instituting lavage. The successful use of a carbonated beverage to treat human patients for oesophageal or gastrointestinal obstruction caused by a phytobezoar is well documented. Carbonated beverages have also been reported to be effective in treating horses for gastric and enteric impactions caused by persimmon seeds. Administering cola into the oesophagus may help resolve oesophageal obstruction of horses caused by a phytobezoar or impacted feed material when horses are refractory to other treatments.     

Gastric carcinoma in a dog

An 8–year-old castrated male Bassett hound had been vomiting intermittently for 3 weeks. In addition, clinical signs of anorexia, weight loss, dehydration, depression and anterior abdominal pain were noted. Gastro-scopic and radiographic examination revealed a mass at the pyloric region of the stomach. Clinical remission followed surgical excision of gastric carcinoma, with recurrence of vomiting 4 months after surgery. At necropsy, the pyloric region of the stomach was markedly thickened, rigid, scirrhous and had an excavated ulcer. The pathological diagnosis was a poorly differentiated, diffuse gastric carcinoma with metastasis to regional lymph nodes.     

Effect of orally administered cimetidine and ranitidine on abomasal luminal pH in clinically normal milk-fed calves

OBJECTIVE: To characterize the change of pH in the abomasal lumen throughout a 24-hour period, to determine whether pH of the abomasal body differs from pH of the pyloric antrum, and to determine whether oral administration of cimetidine and ranitidine alters pH of the abomasal lumen in milk-fed calves. ANIMALS: 5 male dairy calves (4 Holsteins-Friesian, 1 Ayrshire), 5 to 15 days old. PROCEDURE: Cannulas were surgically positioned in the abomasal body and pyloric antrum of each calf. Calves received the following treatments in a randomized crossover design: milk replacer (60 ml/kg of body weight, q 12 h [untreated control calves]), milk replacer and cimetidine (50 or 100 mg/kg, q 8 h), or milk replacer and ranitidine (10 or 50 mg/kg, q 8 h). The pH of the abomasal body and pyloric antrum was measured for 24 hours, using miniature glass pH electrodes. RESULTS: Suckling of milk replacer immediately increased abomasal luminal pH from 1.4 to 6.0, followed by a gradual decrease to preprandial values by 6 hours. Preprandial and postprandial pH values were not significantly different between the abomasal body and pyloric antrum, indicating lack of pH compartmentalization in the abomasum of milk-fed calves. Administration of cimetidine and ranitidine caused a significant dose-dependent increase in mean 24-hour abomasal luminal pH. CONCLUSIONS AND CLINICAL RELEVANCE: Abomasal acid secretion in milk-fed calves is mediated in part by histamine type-2 receptors. Cimetidine and ranitidine may be efficacious in the treatment of abomasal ulcers in milk-fed calves.     

Immunohistochemical study of the ontogeny of prochymosin--and pepsinogen-producing cells in the abomasum of sheep

The appearance and development of prochymosin- and pepsinogen-producing cells were investigated in the ovine abomasum from fetus to adult using immunohistochemistry. Prochymosin immunoreactivity appeared first in the proper gastric glands of the 100-day-old fetus. The intensity and distribution of prochymosin-immunoreactive cells increased gradually with the progress of gestation, and their most intense immunoreactivities and widest distribution were observed in 3-day-old lambs. They were subsequently reduced throughout postnatal growth. A few prochymosin-immunoreactive cells were scattered in the glands of adult sheep. Pepsinogen immunoreactivity appeared at first in a small number of cells in the base of some proper gastric glands of 120-day-old fetuses. After 130 days, pepsinogen-immunoreactive cells increased their staining intensities and distribution. They reached a peak in area at 21 days, which is comparable to adult sheep. In the pyloric glands, prochymosin- and pepsinogen-immunoreactive cells appeared from 100 and 130 days, respectively. Numbers were reduced in comparison to gastric glands and their occurrence was capricious. The results demonstrated that the ontogeny of prochymosin- and pepsinogen-immunoreactive cells in the abomasum of sheep is more similar to that in cattle than to that in the goat. The present data will contribute to the overall understanding of the development of ruminant gastric proteases.     

Immunohistochemical Study of Endocrine Cells in the Gastrointestinal Tract of the Philippine Carabao (Bubalus bubalis)

The distribution and frequency of occurrence of endocrine cells in the gastrointestinal tract of the Philippine carabao (Bubalus bubalis) were studied by immunohistochemistry. Fourteen types of immunoreactive (IR) endocrine cells were revealed. Among the cell types, only chromogranin, serotonin, and bovine pancreatic polypeptide (BPP) were present in the entire gut, while the others showed restricted distribution: somatostatin, gastrin, and cholecystokinin in the abomasum and small intestine; methionine-enkephalin-Arg⁶-Gly⁷-Leu⁸, motilin, neurotensin, secretin, gastric inhibitory peptide, and substance P in the small intestine; peptide tyrosine tyrosine (PYY) in the large intestine: and glucagon in the whole intestinal tract. Most of the cell types showed peak density in the pyloric, duodenal, or rectal region. The highest cell type heterogeneity was observed in the duodenum. The distribution profile of the gut endocrine cells in the carabao is closely related to that in the Holstein cattle. Important findings include the occurrence of BPP-IR cells in the entire gut and the high frequency of PYY-IR cells in the large intestine.     

ASPECTS OF THE PHYSIO-PATHOLOGY OF PARASITIC GASTRITIS IN THE SHEEP

Sheep and calves prepared with separated, innervated pouches made from the acid secreting region of the abomasum were given single or multiple infections of Ostertagia spp and comparisons were made of the secretory changes of parasitised and non-parasitised mucosa by means of cannulas placed in the abomasum and pouch. Contrary reactions of the parasite-free pouches and infected main part of the abomasum are described and explained in terms of a two-part hypothesis. The inhibitory effect on acid secretion of the abomasum (resulting in its contents being pH 5 to 7) was postulated to be due to the direct suppressive effects of substances released locally by parasites or injured host tissues, whereas increased secretion of the hormone, gastrin, was thought to account for the stimulatory effects of infection on acid secretion from the pouches. In sheep treated with anthelmintic and then reinfected the inhibitory effects on abomasal pH were not obtained. The hypersecretion from the pouches still persisted.     

Effects of the two production programs ‘Naturafarm’ and ‘conventional’ on the prevalence of non-perforating abomasal lesions in Swiss veal calves at slaughter

Non-perforating abomasal lesions are a considerable problem affecting more than half the population of veal calves. The objective of the present study was to assess the prevalence of pyloric and fundic abomasal lesions in Swiss veal calves at slaughter and to compare the occurrence of non-perforating abomasal lesions between two different production programs (‘Naturafarm’ and ‘conventional’). ‘Conventional’-production settings met the minimal standards as defined by the Swiss animal welfare legislation, whereas ‘Naturafarm’ production complied with increased animal welfare requirements. In order to identify risk factors for the development of abomasal lesions, information on management, housing, and feeding was obtained by a questionnaire. A total of 125 abomasa were randomly selected in one large abattoir. They were examined macroscopically, and the occurence of lesions in either the fundic or pyloric region of the abomasum was recorded separately. Animals raised in the ‘conventional’-production setting revealed a significantly higher prevalence of lesions in the fundic part. Factors significantly affecting the prevalence of non-perforating lesions in the fundic part were the ‘conventional’-production environment, including missing access to an outside pen, missing access to water and straw as the only roughage, feeding by bucket and the liquid milk by-product Protofit in combination with the powder Sprayfit.