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1.
On the fine structure of the fetal goblet cells in the bovine small intestineEarly in the fetal development, i.e. at the time both of the growth of intestinal villi and crypts and the epithelial cell differentiation the goblet cells also appear. The maturation of goblet cells progresses during their migration from the base of the villi respectively of the crypts to the villous top. As in the bovine large intestine there are vesicles and capsulated vacuoles, which contain vesicles, as single elements or as conglomerates in the immature goblet cells of the small intestine. These images deliver a scenario of the mechanism of secretory granule production and probably play a role in the formation of mucus.  相似文献   

2.
Early in the fetal development, i.e. at the time both of the growth of intestinal villi and crypts and the epithelial cell differentiation the goblet cells also appear. The maturation of goblet cells progresses during their migration from the base of the villi respectively of the crypts to the villous top. As in the bovine large intestine there are vesicles and capsulated vacuoles, which contain vesicles, as single elements or as conglomerates in the immature goblet cells of the small intestine. These images deliver a scenario of the mechanism of secretory granule production and probably play a role in the formation of mucus.  相似文献   

3.
Small and large intestines of seven specific pathogen-free lambs infected with cryptosporidia from calves with diarrhea were examined by scanning and transmission electron microscopy and by light microscopy. The small intestine was infected in all the lambs, and the cecum and colon in three. Small intestinal alterations were severe villous atrophy and dilatation of the crypts of Lieberkühn. Epithelial cross-bridging between contiguous villi caused much villous fusion. Epithelial cells constituting the bridges were connected by desmosomal junctions, and were continuous with the epithelial coverings of the associated villi. The lamina propria was heavily infiltrated with neutrophil leukocytes. Infected crypts in cecum and colon were dilated and devoid of mucus-secreting cells, while the ridges between crypts were hypertrophied, and the lamina propria was infiltrated by neutrophils. Cell vegetations with adherent bacteria were present in the surface intestinal epithelium of two lambs infected for 11 and 14 days, respectively. No adherent bacteria were seen in any site in lambs killed up to six days post-inoculation.  相似文献   

4.
Sixteen 2–3-days-old caesarean-derived, colostrum-deprived piglets were each dosed oro-nasally with 2 ml of a bacteria-free filtrate containing 104 pig-infectious-doses of CV 777. The piglets were killed at intervals of 12 to 120 h after infection. The coronvirus-like agent caused a local infection of the intestinal tract which resulted in villous atrophy, malabsorption and diarrhea. The pathogenesis of this infection was similar to that of transmissible gastroenteritis (TGE), a known coronaviral infection of pigs. However, where were some differences. By immunofluorescent staining, CV 777 antigens were not only detected in the epithelial cells covering the small intestinal villi, but also in the cells of the colonic surface epithelium. Occasional fluorescence was also seen in the small intestinal crypt epithelium, but the regenerative capacity of the crypts was not affected. The progress of intestinal epithelial cell infection by CV 777 was much slower than that in TGE, resulting in a longer incubation period and in less drastic epithelial cell destruction. The infection of regenerating cells occurred to a much higher degree during the late stage of a CV 777 infection than has been observed in TGE.  相似文献   

5.
The equine alternative complement pathway has been partially characterized and compared to the equine classical activation pathway. A dose-dependent lysis of RbRBC was observed with peak lytic values noted within 10 minutes at 37°C when rabbit red blood cells (RbRBC) were used as an alternative pathway activator. Sheep red blood cells (SRBC) sensitized with rabbit hemolysin or partially purified equine IgM antibodies were equally sensitive to lysis. Dilution of the commercial hemolysin by 15 reduced lysis from 90% to 38% in the presence of constant cell numbers. Hemolysis of SRBC peaked at 10 minutes and the majority of lysis occurred within 10 minutes. Dilution of equine sera by as little as 15 decreased hemolytic activity for SRBC to 21.5% from greater than 90% with undiluted sera. The alternative pathway protein, equine factor B, was tested using RbRBC and monitored by its differential susceptibility to heat treatment at 50°C. This treatment led to almost complete inactivation after a 15-minute incubation. An apparent heat-dependent decay of certain classical pathway components was also observed after 50°C treatment. This sensitivity was indicated by a reduction in the lytic activity for sensitized SRBC. Treatment for 15 minutes at 56°C with either RbRBC or SRBC was sufficient to abolish hemolytic activity in all equine sera tested. Chelation of cations with 0.04 M EDTA blocked expression of alternative and classical pathway activation; however, chelation of Ca++ ions with 10 mM EGTA containing 1 mM Mg++ ions permitted lysis of the RbRBC but not the SRBC. A dose-related Mg++-ion dependence for RbRBC hemolytic activity was observed as the concentration of Mg++ was increased to 1.0 mM. In addition, our results obtained with pre-colostral foal serum strongly suggest that natural antibody to RbRBC was of little importance in the lysis observed with these cells. These results also show that the equine alternative pathway activation may require Ca++ ions. If Ca++ ions are required, the equine alternative pathway is quite different from any other mammalian complement system so far described. Our results suggest that the alternative pathway of activation is of major importance in the equine complement system. Confirmation of this hypothesis requires both purification of the components involved as well as further characterization.  相似文献   

6.
The development of the bovine small intestine was examined in 24 embryos and fetuses by light microscopic, scanning and transmission electron microscopic methods. Special reference was paid to the genesis of the epithelium and particularly of the villi intestinales. The primitive intestine consists of one layer of epithelial cells surrounded by mesenchym and tunica serosa. The fetal intestine (up to the 24th week of gestation) shows all the morphologic structures of the adult. In small intestine the development of cryptae and villi intestinales starts before the 7th week of gestation and progresses with a proximo-distal gradient. Epithelial proliferation that gives rise to primary epithelial villi makes epithelium become temporarily stratified. Finger-like secondary villi develop by proliferation of the mesenchym. In addition to this process mucosal folds occur in duodenum giving rise to villi by segmentation. At the same time the differentiation of epithelium starts. The fetal small intestine, like many other fetal tissues displays masses of glycogen.  相似文献   

7.
The present light microscopic study describes the morphological changes which occur in the duodenal mucosa of the bovine fetus from the third month of gestation until birth with regard to the sequence of appearance and morphology of enterochromaffin cells. The mucosa of the duodenum is prepared for digestive activity during the first months of development. This becomes obvious in the early differentiation of the fetal intestinal mucosa. The enterocytes in villus epithelium contain glycogen in the early months. These glycogen pools seem to shrink during the following months. They may provide a metabolic reserve for the fetus, which derives all of its nutrition from carbohydrates. Enterochromaffin cells appear in the three month old bovine fetus with two cell-types situated in the epithelial lining of crypts and villi. The density of enterochromaffin cells increases during gestation. There were no findings to indicate that the fetal enterochromaffin cells did not originate from endoderm. The early appearance from enterochromaffin cells (which are the producers of serotonin, 5-hydroxytryptamine) correlates with first gastrointestinal movements, which are known to commence in the first third of gestation, leading us to believe that 5-HT represents the chemical inducer of muscular motility in the developing intestine.  相似文献   

8.
A warm complement fixation test that will detect antibody in sheepserum in the virtual absence of anti-complementary activity is described. Sheep antibody-antigen complexes were detected by fixation of sheep complement. Sheep serum, heparinized or Mg++—EGTA plasma was used as the source of sheep complement. Sheep-antibody-sensitized human erythrocytes were used as the haemolytic indicator cells for sheep complement. As the modified complement-fixation test was performed in the presence of Mg++—EGTA, sheep C probably reacts with sheep Ab-Ag complexes by a different mechanism than does guinea-pig complement.  相似文献   

9.
Abstract

The effect of long-term freshwater acclimation on the blood and plasma ion composition of Red Drum Sciaenops ocellatus was investigated with the goal of elucidating the necessity of ion remediation. Four replicates (n = 50) of freshwater-acclimated (FW) fish (1.6 ± 0.2 g) were raised in 25-m3 tanks supported by 140,000 L of recirculating water. Four replicates (n = 50) of seawater (SW) fish groups were placed in 40-m3 offshore cages at 32–35 psu. Blood was collected from 100 fish (FW = 578 ± 50 g; SW = 686 ± 45 g) of each group (FW, SW) after 8 months of rearing. During the grow-out phase, the survival of FW and SW fish was 57.5% and 92.2%, respectively. The water ion composition (mainly the Ca2+/K+ [43%] and Ca2+/Mg2+ ratios [1%]) explained 56.6% of the plasmatic ion variability in the fish groups. Freshwater exposure produced significant reductions in osmolality and in several plasma indicators (Na+, Cl?, and Mg2+); the K+ levels from FW fish were the most compromised parameter. The water Ca2+/Na+ ratio had a greater influence (44%) on the plasma chemistry parameters, mainly glucose and creatinine. Freshwater-acclimated fish had a higher percentage of hematocrit, hemoglobin, and red blood cells than SW fish, but the water quality explained only 12.5% of the blood parameter variability between the FW and SW groups. The results support the conclusion that Red Drum tolerates salinity variations and can adopt a relatively stable condition for short periods; however, the data suggest that Red Drum have only a limited ability to withstand a hyposmotic environment for long periods due to their limited ability in maintaining K+ concentrations without external supplementation. Freshwater environments with high Ca2+/Na+, Ca2+/K+, and Ca2+/Mg2+ ratios appear to be a chronic stress factor that should be considered in future experiments.

Received June 11, 2012; accepted March 17, 2013  相似文献   

10.
Although the histology of the intestinal tract of Crocodylus niloticus is touched on in overall studies on reptilian intestinal tract, a more comprehensive light microscopical study on this area is lacking. Specimens for histological examination were taken from the duodenum, the jejunum, the ileum and the rectum. The data obtained revealed that the mucosa is thrown into folds and simple, slightly branched tubular intestinal glands. The mucosal folds diminished in height and eventually disappeared upon reaching the ileorectal junction. The epithelium covering the folds and crypts was of the simple columnar type. Clear marginal cells, goblet cells and argentaffin cells were observed throughout the intestinal tract. No Paneth cells were seen in this study. The lamina propria was rich in lymphocytic infiltrations while the muscularis mucosa consisted mainly of an outer longitudinal layer, the inner circular layer being rudimentary or absent. The submucosa was extremely narrow, and the circular and longitudinal layers of the tunica muscularis contained distinct layers of dense fibrous connective tissue. The histology of the intestinal tract of C. niloticus is shown to be in line with the situation in crocodilians and also exhibits a resemblance to that of carnivorous mammals.  相似文献   

11.
Ion-selective electrodes have recently been designed for determining the ionized concentration of magnesium (Mg2+) in serum. This development may allow new insights into some metabolic diseases of cattle. For this report, the concentrations of Mg2+, total magnesium (Mgtot), ionized calcium (Ca2+), total calcium (Catot), and inorganic phosphate (Pi) were determined in sera from seventeen 3-to 16-year-old Brown Swiss and crossed Simmental/Red Holstein cows during the periparturient period. In each animal, a transient increase of Mg2+ and Mgtot serum concentrations was observed in association with the transient decrease in serum concentrations of Ca2+, Catot and Pi after parturition. On average, throughout the study, the serum Mg2+ concentrations were 68.5% of those of Mgtot, whereas the serum Ca2+ concentrations were 52% of those of Catot. The possible mechanisms involved in the transient increase of Mg2+ and Mgtot serum concentrations are discussed.Abbreviations Ca2+ ionized calcium - Catot total calcium - Mg2+ ionized magnesium - Mgtot total magnesium - Pi inorganic phosphate - PTH parathyroid hormone - PTHrP parathyroid homrone related protein  相似文献   

12.
The present work was aimed to study the gastrointestinal tract in Garganey from the oesophagus to coprodeum by the aid of the gross morphology, scanning electron microscopy and histology. At the level of the thoracic inlet, the oesophagus had a thick part which had numerous tortuous longitudinal folds carried transverse folds on them. Histologically, the thick part had thick epithelium and appeared more folded with more and larger glands. The mucosa of the proventriculus had mucosal folds appeared as a leaf-like with rounded tips. The openings of the proventriculus glands were projected with papillae on the epithelial surface. The gizzard lined with horizontal layer of cuticle which sent vertical parts of cuticle. The duodenal villi were pentagonal in shape with sharply pointed tips, while the jejunal villi were triangular with rounded ends, and the ileal villi were wide and pentagonal in shape with pointed tips. The mucosa of the duodenum, jejunum and ileum was thrown into villi lined by simple columnar epithelium with goblet cells with difference in the form, length, density and number. The apical points of the duodenal and ileal villi appeared pointed, while the jejunal villi had rounded ends. The jejunal villi were longer and numerous than the duodenal villi, but the ileal villi appeared with different length and less numerous. The mucosa of the caecum had numerous mucous glands which surrounded by circular crypts. The rectal mucosa had longitudinal folds and semilunar and circular crypts. The mucosa of the coprodeum had longitudinal folds surrounded by crypts.  相似文献   

13.
Lactoferrin is a natural compound in the milk of mammals and was shown to influence the intestinal micro‐flora and the immune system in mice, calves, dogs and man. The present study was carried out to investigate the effect of orally administered bovine lactoferrin (0, 30, 60 and 120 mg/kg DM feed) on the intestinal morphology and lymphocyte colonization in 36 motherless raised puppies. Endoscopic biopsies from duodenum and colon, taken in week 14, were scored histologically after staining with haematoxylin and eosin (H&E) and lymphocytes (CD3+, CD4+, CD8+) and plasma cells (IgA+, IgG+, IgM+) were enumerated after immunohistochemical staining by computer‐aided quantification. Histological scoring revealed no significant differences amongst the groups. IgG+ plasma cells were reduced (p < 0.05) in the lamina propria of the colon of the 30 and the 60 mg group. The number of CD8+ lymphocytes was higher (p < 0.05) in the epithelium of the colon of the lactoferrin groups. In conclusion, this study indicated only minimal effects of bovine lactoferrin on the population of selected immune cells in the gut mucosa of puppies. More investigations are needed to describe the impact of lactoferrin on the digestive physiology of puppies.  相似文献   

14.
The murine model has been widely used to study the host immune response to Neospora caninum. However, in most studies, the intraperitoneal route was preferentially used to establish infection. Here, C57BL/6 mice were infected with N. caninum tachyzoites by the intragastric route, as it more closely resembles the natural route of infection through the gastrointestinal tract. The elicited T-cell mediated immune response was evaluated in the intestinal epithelium and mesenteric lymph nodes (MLN). Early upon the parasitic challenge, IL-12 production by conventional and plasmacytoid dendritic cells was increased in MLN. Accordingly, increased proportions and numbers of TCRαβ+CD8+IFN-γ+ lymphocytes were detected, not only in the intestinal epithelium and MLN, but also in the spleen of the infected mice. In this organ, IFN-γ-producing TCRαβ+CD4+ T cells were also found to increase in the infected mice, however later than CD8+ T cells. Interestingly, splenic and MLN CD4+CD25+ T cells sorted from infected mice presented a suppressive activity on in vitro T cell proliferation and cytokine production above that of control counterparts. These results altogether indicate that, by producing IFN-γ, TCRαβ+CD8+ cells contribute for local and systemic host protection in the earliest days upon infection established through the gastrointestinal tract. Nevertheless, they also provide substantial evidence for a parasite-driven reinforcement of T regulatory cell function which may contribute for parasite persistence in the host and might represent an additional barrier to overcome towards effective vaccination.  相似文献   

15.
Comparative studies of ionic composition, osmolality, protein concentration and pH of seminal plasma along with spermatozoa concentrations were carried out in stellate sturgeon, Acipenser stellatus, and Russian sturgeon, Acipenser gueldenstaedtii. Analysis of A. gueldenstaedtii sperm showed significantly higher concentrations of Na+ (34.58 ± 4.61 mm ), Ca2+ (0.35 ± 0.12 mm ), Mg2+ (0.70 ± 0.25 mm ), Cl? (13.50 ± 4.04 mm ) and proteins (0.60 ± 0.29 mg/ml) in the seminal plasma than did seminal plasma of A. stellatus: Na+ (20.08 ± 10.75 mm ), Ca2+ (0.28 ± 0.06 mm ), Mg2+ (0.29 ± 0.05 mm ), Cl? (7.50 ± 3.00 mm ) and 0.30 ± 0.11 mg/ml proteins. Significantly higher concentration of K+ (5.42 ± 1.06 mm ) was observed in A. stellatus compared to A. gueldenstaedtii K+ (2.29 ± 0.50 mm ). Concentration of Na+ was positively correlated with osmolality (r = 0.819), levels of Cl? (r = 0.922) and Mg2+ (r = 0.727) and pH (r = 0.848). The concentration of Mg2+ was positively correlated with protein concentration (r = 0.774), Na+ (r = 0.727), Cl? (r = 0.872) and Ca2+ (r = 0.801). A positive relationship was also found between concentration of K+ and spermatozoa concentration (r = 0.709). Results revealed strong inter‐species differences in several parameters. The data should be useful for artificial fertilization and for cryopreservation of sturgeon sperm.  相似文献   

16.
The presence and distribution of glucose-dependent insulinotropic polypeptide or gastric inhibitory polypeptide (GIP), gastric-releasing peptide (GRP) and glucagon immunoreactivity were studied in the small intestine of the New Hampshire chicken using immunohistochemistry. This is the first report of the presence of GIP-immunoreactive (ir) cells in avian small intestine. GIP, GRP and glucagon immunoreactivity was localized in the epithelium of the villi and crypts of the duodenum, jejunum and ileum. In particular, both in the duodenum and in the jejunum immunoreactive endocrine cells to GIP, GRP and glucagon were observed. In the ileum, we noticed GIP-ir and glucagon-ir cells. GRP-ir was found in nerve fibres of all three segments of the small intestine. The distribution of these bioactive agents in the intestinal tract of the chicken suggests that GIP and glucagon may play a role in the enteropancreatic axis in which intestinal peptides modulate pancreas secretion.  相似文献   

17.
The incidence and location of CD2+, CD4+, CD8+ and γ/δ T lymphocytes and IgM+ B lymphocytes were studied in the intestinal lymph nodes in 1-week, 1-month, 3-month and 7-month-old goats, using monoclonal antibodies and immuno-histochemical methods. The cortical area of the intestinal lymph nodes in 1-week-old animals contains only primary follicles occupied by IgM+ B lymphocytes and some CD2+CD4+ T lymphocytes. In goats older than 1 month, secondary follicles, that increased in number and size with age, were observed; the light zone of the germinal centre was occupied by IgM+ lymphocytes and some CD2+ and CD4+ T lymphocytes. In the other compartments of the lymph nodes, B lymphocytes were scarce, their number increasing with age in the medulla and diminishing in the paracortex. The numerous CD2+ T lymphocytes in the interfollicular area increased in number in the paracortical area of the 7-month-old goats, simultaneously with an increase in the MHC II+ dendritic cells and the CD4/CD8 ratio, which was greater than 1. The γ/δ T lymphocytes represented a minor subpopulation scattered through the lymph nodes.  相似文献   

18.
The quantitative and distribution patterns of porcine peripheral blood and tonsillar lymphoid/myeloid cell subsets were assessed in order to establish the immune status of farm pigs prior to their transfer to fattening units. Peripheral blood and tonsillar samples were taken from clinically healthy, nonvaccinated, 12-week-old pigs, either ex vivo or following euthanasia. Single-colour flow cytometry, using monoclonal antibodies (mAbs) reactive with the swine leukocyte cluster of differentiation (CD) antigens, gave the proportions of lymphoid (9.7% CD4+, 8.0% CD8+, 36.9% CD5a+, 20.3% CD16+, 6.9% CD21+, 86.3% CD45+, 41.8% CD45RA+, 48.3% CD45RC+), null cells (6.9%) and myeloid cells (23.7% CD11b+ and 5.4% SWC3a+) in peripheral blood. In situ identification and distribution of lymphoid cells in the tonsils (CD3a+, CD21+, CD45RA+, CD45RC+) was performed with anti-CD mAbs using the avidin–biotin complex method. Most CD3a+ cells were in the parafollicular areas, with many cells in the follicles. CD21+ cells were scattered throughout the parafollicular area, with only a few cells inside lymphoid follicles. CD45RA+ cells were mostly concentrated in the follicles but many positive cells were present in the parafollicular area. Many CD45RC+ cells were visible in the parafollicular area, a few positive cells were in the crypt epithelium, and single cells were inside the follicles.  相似文献   

19.
Embryos of Clinus dorsalis absorb nutrients from the embiyotrophe, secreted by the follicular epithelium. Autoradiographic studies revealed that the principal areas of nutrient absorption are the embryonic gut and epidermis. A histological and electron microscopic study of embryonic structure revealed an extensively hypertrophied gut with numerous flngerlike villi projecting into the gut lumen. A brushborder of microvilli is, furthermore, characteristic of the columnar gut epithelium. Epidermal surface area is increased apically on individual epidermal cells, particularly on the ventral pericardial surface. Micro ridges further increase epidermal surface area. Epidermal surface area is reduced and a mucous layer is secreted prior to parturition.  相似文献   

20.
The normal ultrastructure of the intestinal epithelium of F. hepatica has been described in detail e. g. by Thorsell & Björk- man (1965). However, experimentally produced pathological phenomena of the epithelium have not been investigated, though such studies might yield further information on the physiological function of the epithelial cell. Light and electron microscopy of the intestinal epithelium during in vitro cultivation of the liver fluke does therefore seem to be appropriate. This preliminary report, giving an account of the cultivation procedures, deals only with light microscopy of the cultivated liver flukes.  相似文献   

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