The relationship of abnormal mucosal microtopography with distribution of Trichostrongylus colubriformis in the small intestines of lambs

The relationship of abnormal mucosal microtopography with distribution of Trichostrongylus colubriformis in the small intestines of lambs. International Journal for Parasitology4: 153–163. The distribution of T. colubriformis was studied by counting worms in sequential 1-m segments from the guts of 14 infected lambs. Mucosal morphology was described at corresponding 1-m intervals and compared with similar samples from uninfected controls. A mean of 90 per cent of worms was recovered in the first 6 metres of gut. Maximum worm counts occurred in the first (eight lambs) second (three lambs) or third (three lambs) metre. Less than 0·8 per cent of worms were found in the abomasa of five lambs. Flat mucosae or abnormal surface patterns were seen frequently in the anterior small intestine of infected lambs. Degree of mucosal abnormality was positively associated with magnitude of worm numbers/m, and negatively correlated with distance of the sample from the pylorus, by analysis of partial correlation of worm numbers/m, mucosal type score, and distance from the pylorus. Mucosae from areas with > 4000 worms/m tended to have significantly shorter villi than intestine of control lambs. Factors influencing worm distribution and pattern of establishment are discussed, as is the association of extreme villus atrophy with poor performance by infected lambs.     

Investigation of the protective effects of crocin on acrylamide induced small and large intestine damage in rats

We investigated repair of acrylamide (AA) induced damage in intestines by administration of crocin. We used 40 male Wistar rats in four groups of 10 animals: control, AA, crocin, and AA + crocin groups. We investigated biochemical and histological changes to small and large intestine. AA ingestion decreased glutathione (GSH) levels and total antioxidant status (TAS) in the intestine compared to the control group, while superoxide dismutase (SOD) and catalase (CAT) activities, and total oxidant status (TOS) and malondialdehyde (MDA) levels were increased. Villi were shortened and villus degeneration was observed in ileum of the AA group. Degeneration of surface epithelium and Liberkühn crypts were observed in colon sections. GSH and TAS levels increased after administration of AA together with crocin, while SOD and CAT levels and TOS and MDA levels decreased; significant recovery of histological damage also was observed. We found that crocin exhibits protective effects on AA induced small and large intestine damage by inhibiting oxidative stress.     

Characterization of macrophage-like cells in the external layers of human small and large intestine

Summary In the external layers of human small and large intestine macrophage-like cells were characterized by immunohistochemical, histochemical and electronmicroscopical methods. Using immunohistochemistry and a number of monoclonal antibodies, the presence and distribution of phenotypic subpopulations of macrophages were evaluated. In all locations macrophage-like cells were identified with antibody EBM11, which recognizes CD68 antigen, C3bi which recognizes CD11b, and partly with an antibody which recognizes protein 150,95 (CD11c). Macrophage-like cells in the external muscle layer were HLA-DR-positive (expressing the MHC class-II antigen), in contrast to macrophage-like cells in the subserosa and submucosa. Macrophage-like cells in the external muscle layer were mostly acid phosphatase-negative, and at the electron-microscopic level they were found to have features of macrophages: primary lysosomes, coated vesicles and pits. However, very few secondary lysosomes were present. Birbeck granules were not observed. It is concluded that in the external muscle layer of human small and large intestine numerous macrophages of a special type are present. It is discussed whether this cell type plays a role in gastrointestinal motility and/or has an immunological function.     

GLP-2对小鼠小肠黏膜的作用及不同脏器分布的影响

目的：观察胰高血糖素样肽-2对小鼠小肠黏膜的作用效果及其受体在不同脏器的分布和表达。方法：选用5-6周龄的雄性健康BALB/C小鼠,体重17～20g。随机分为3组。对照组8只;脑内注射GLP-2组9只,每天按25μg/kg脑内注射GLP-2液2次,连续3天;腹腔注射GLP-2组9只,每天按250μg/kg腹腔注射GLP-2液2次,连续3天。3天后,处死小鼠,做组织切片进行HE染色,观察小鼠小肠黏膜的组织学变化,用免疫组化方法检测GLP-2R在不同脏器的表达和分布。结果：小鼠经腹腔注射GLP-2后,小肠不同肠段黏膜的绒毛高度较对照组明显增加（P〈0.05）,脑内注射组的肠黏膜无明显形态学变化;GLP-2R在小鼠胃、空肠与结肠部位均有表达,而食管与肝显阴性;腹腔注射组的GLP-2R表达较对照组显著下调（P〈0.05）。结论：GLP-2能刺激小肠黏膜上皮增厚,增加小肠不同肠段黏膜的绒毛高度;小鼠的胃、空肠与结肠经GLP-2（腹腔注射）处理后其受体表达下调。     

Transient changes of enzyme activities and expression of stress proteins in the small intestine of piglets after weaning

To determine the transient effects of weaning on the small intestine, 16 piglets were slaughtered at days 0, 1, 4 and 7 after weaning. Jejunal samples were collected to examine different enzyme activities and mRNA expressions of two stress protein families, namely, heat-shock proteins (HSP) and trefoil factors (TFF). Results showed that the activities of ceruloplasmin, alkaline phosphatase and lactate dehydrogenase, were significantly changed at Day 1 and/or Day 4. The mRNA expressions of HSP10, HSP60 and HSP90 showed a pattern of increased expression with time after weaning. Expression significantly differed between Day 0 and Day 7 after weaning. The mRNA expression of HSP70 was significantly increased on Day 1 only. Similarly, the mRNA expressions of TFF1 and TFF2 were significantly increased on Day 7 compared with those on Day 0. Expression of TFF3 was not affected by time after weaning. In conclusion, the present study indicated that weaning induced transient injury to small intestinal morphology and function. Particularly it changed enzyme activities and gene expression of stress proteins in the small intestine of piglets. At first time, a change in the gene expression of HSP10 and a gene overexpression of TFF1 in the small intestine of piglets after weaning was found.     

Spectroscopic studies on the denaturation of papain solubilized and Triton X-100-solubilized glucoamylase from rabbit small intestine

Intestinal brush border proteins consist of an enzymatically active hydrophilic moiety attached to a hydrophobic tail. Papain dissociates the hydrophilic part by cleaving off the hydrophobic tail, whereas the detergentTriton X-100 solubilizes the whole molecule. Denaturation by 8 M urea or 4 M guanidinium chloride does not alter the structure of the papain-solubilized enzyme. An appreciable alteration of the structure of detergent-solubilized enzyme was observed on denaturation. The difference spectra of Triton X-100 (1%)—solubilized enzyme and its urea denatured form shifts and intensifies, with increase in the concentration of the denaturant with an isobestic point at 252 nm. A new band at 280 nm also appears at 4 M urea concentration. Papain-solubilized glucoamylase has an ∞ -helical conformation in solution unlike the detergentsolubilized fraction. An elongated structure for the papain solubilized enzyme is inferred from the urea denaturation studies and from molecular weight determinations.     

The influence of level of infection of rats with Nippostrongylus brasiliensis on the haematology and phospholipase activity and mast cell numbers in the small intestine and colon

The haematology and phospholipase activity and mast cell numbers of the small intestine and colon of rats was studied 10 days after infection with various numbers of larvae of N. brasiliensis. A significant reduction in the RBC occurred after infections with 200 and 5000 larvae but not with 1000 larvae. Hb was significantly reduced after infection with 200 larvae and increases in the MCV and MCH indicated the development of a macrocytic anaemia. Reticulocyte count was increased at all levels of infection except after 200 larvae. WBC was increased at all levels of infection except in the 5000 larvae group. Lymphocytes were significantly increased in all groups except those infected with 5000 larvae. Neutrophils increased only at the lower levels of infection. The most marked changes occurred in eosinophil numbers, significant increases occurring with increasing levels of infection. However, after infection with 5000 larvae the numbers were significantly lower than after infection with 200 or 1000 larvae. Phospholipase activity, which is believed to be related to tissue eosinophil levels, was significantly increased at all infection levels in the proximal small intestine. Significant increases in the distal ileum and colon occurred mainly after infection with 1000 and 5000 larvae. Mast cell numbers did not change significantly at any infection level. It is suggested that the pathology observed, here in the form of anaemia, is multifactorial in origin and is largely a function of the immune response, the development and expression of which is dependent on the level of infection, with suppression of immune damage occurring at the high levels of infection when pathogenesis may involve a direct effect of the worms.     

The effect of dexamethasone treatment on the expression of the regulatory genes of ketogenesis in intestine and liver of suckling rats

The influence of the injection of dexamethasone on ketogenesis in 12 day old suckling rats was studied in intestine and liver by determining mRNA levels and enzyme activity of the two genes responsible for regulation of ketogenesis: carnitine palmitoyl transferase I (CPT 1) and mitochondrial HMG-CoA synthase. Dexamethasone produced a 2 fold increase in mRNA and activity of CPT I in intestine, but led to a decrease in mitt HMG-CoA synthase. In liver the mRNA levels and activity of both CPT I and mitt HMG-CoA synthase decreased. Comparison of these values with the ketogenic rate of both tissues following dexamethasone treatment suggests that mitt HMG-CoA synthase could be the main gene responsible for the regulation of ketogenesis in suckling rats. The changes produced in serum ketone bodies by dexamethasone, with a profile that is more similar to the ketogenic rate in the liver than that in the intestine, indicate that liver contributes more to ketone body synthesis in suckling rats. Two day treatment with dexamethasone produced no change in mRNA or activity levels for CPT I in liver or intestine. While mRNA levels for mitt HMG-CoA synthase changed little, the enzyme activity is decreased in both tissues.     

The effect of the high lysine genes of the barley mutants Risø 1508 and 527 on embryo development

Dry weight of 34-day-old embryos from barley ( Hordeum vulgare L.) cv. Bomi and high lysine mutants 527, 1508 and the double mutant 527/1508 were 1.00, 1.13, 1.56 and 2.22 mg, respectively. Embryos of the four lines were compared by light and electron microscopy and two dimensional gel electrophoresis. Morphological differences were restricted to the scutellar tissue, which had an irregular form in 1508 and the double mutant. Average scutellar cell volumes in 34-day-old embryos from cv. Bomi, mutants 527, 1508, and 527/1508 were 4 200, 8 300, 4 900 and 23 400 μm³. respectively. The starch content of the scutellar parenchyma cells was slightly higher in mutant 527 than in cv. Bomi, and considerably higher in mutant 1508 and the double mutant. The two dimensional gel electrophoretic examination showed that seven of the embryo protein spots were of a significantly different size in the mutants relative to those from cv. Bomi. Among these seven proteins, one was apparent only in the double mutant, four were more abundant in the mutants than in cv. Bomi and two were less abundant. The isoelectric points and the molecular weights of these proteins do not correspond exactly to those of proteins previously described in barley seeds.     

The effect of gamma irradiation at sub- and supralethal doses on the lipid composition of the mucosa and of the brush border membrane of the small intestine in rats]

A study was made of the amount of cholesterol and its ethers (phosphatidyl choline, phosphatidyl ethanolamine, sphingomyelin, phosphatidyl serine, and phosphatidyl inositol) in mucosa and membrane of the small intestine brush border 24 h after 4 Gy and 2 h after 20 Gy irradiation. No changes in the lipid content of mucosa and membrane of the brush border were noted after 4 Gy irradiation. Exposure to 20 Gy radiation doubled the number of cholesterol ethers and made the number of individual phospholipids and cholesterol increase by nearly 1.5 times. The amount of phosphatidyl serine in the brush border membrane increased by almost 3 times; the concentration of other lipids increased by nearly 1.5 times; cholesterol/phospholipid ratio was unchangeable.     

The effect of massive small bowel resection (MSBR) and small intestinal bypass (JIB) in the rat on the enteroinsular axis

The effect of massive small bowel resection (MSBR) and jejuno-ileal bypass (JIB) on the enteroinsular axis in rats was compared. Glucose levels after an oral glucose tolerance test were determined in MSBR, JIB and control animals. The response of the beta-cell mass to glucose and gastric inhibitory polypeptide (GIP) was established in the same animals using the isolated perfused pancreas model. Immunocytochemical and morphological studies were performed to monitor the adaptive changes seen in the intestine of these animals. The glucose response to the oral glucose load was blunted in both test groups with the fasting GIP levels in the JIB group being elevated and the MSBR group being reduced. The response of the isolated perfused pancreas to GIP showed a marked (70%) reduction of insulin release in the JIB rats and a slight but non-significant reduction in the MSBR rats. In both groups the insulin response to glucose alone appeared normal. The area of the pancreatic islets and the percentage of the total area consisting of the four islet cell types (B, A, D, PP) were unchanged. In the intestine the GIP cells were markedly reduced in number in the jejunum of the functional intestine of the JIB rats and the jejunum from the MSBR rats. The GIP cells in the jejunum of the bypass loop did not differ from the control jejunum. The results indicate that the high basal GIP levels seen in the JIB rats were the result of GIP secreted from the blind loop. This study also confirmed the decreased sensitivity of the beta-cells to GIP after JIB while indicating that MSBR has little if any effect on the response of the beta-cell to GIP. These data presented further evidence that the high basal GIP levels were causally related to the decreased insulin response in the JIB rats.     

The effect of dietary supplementation of nitric oxide donor and inhibitor on nNOS expression in and motility of the small intestine of broilers

Abstract

We investigated the effect of dietary supplementation of sodium nitroprusside (SNP), a nitric oxide (NO) donor, and N-nitro-L-arginine methyl ester (L-NAME), a NO inhibitor, on neuronal nitric oxide synthase (nNOS) expression in and motility of small intestinum in broilers. A total of 560, one-day-old Ross 308 hybrid mixed sex broiler chicks were divided randomly into one control and seven treatment groups for a 42 day feeding trial including starter phase (0–21 days) and grower phase (22–42 days). The control group was fed a basal diet and the experimental groups were the fed basal diet supplemented with 25, 50, 100 and 200 mg/kg SNP and 25, 50 or 100 mg/kg L-NAME. Ten chickens from each group were sacrificed to collect samples on days 21 and 42. The expression patterns of nNOS immunoreactivity in nerve fibers were determined by immunohistochemistry. In the contractility studies, longitudinal isolated strips of duodenum, jejunum and ileum were treated with 10^?5 M L-arginine and 10^?4 M SNP. Immunohistochemistry revealed that nNOS expression was not detectable in the duodenum or ileum of either the control or experimental groups. On the other hand, nNOS immunoreactivity in the jejunum control group showed a strong reaction on day 21, but the reaction was weak on day 42. nNOS expression clearly was suppressed on day 21 by the diet supplemented with L-NAME, while the diet supplemented with SNP stimulated nNOS expression on day 21. Contractility experiments revealed that spontaneous contractility of isolated strips of duodenum, jejunum and ileum showed no significant difference among groups. Spontaneous contractions of all strips were inhibited by L-arginine and SNP in all groups. The percentage inhibition rate of spontaneous contractions of jejunum application on days 21 and 42 after L-arginine decreased in the group supplemented with 100 mg/kg L-NAME. The percentage inhibition rate on day 21 after SNP application decreased in both groups that received 50 and 100 mg/kg L-NAME. We demonstrated the expression pattern of nNOS in nerve fibers in jejunum of broiler chickens. Contractility studies revealed that the NOS-NO pathway may play a role in smooth muscle contraction of small intestine of chickens. Feeding strategies that supplement NO donor and NO inhibitor can be of physiological importance to small intestine motility owing to alteration of nNOS expression in the jejunum.     

The effect of membranes on the in vitro fibrillation of an amyloidogenic light-chain variable-domain SMA

Light chain (or AL) amyloidosis is the most common form of systemic amyloidosis, characterized by the pathological deposition of insoluble fibrils of immunoglobulin light-chain fragments in various organs and tissues, especially in the kidney and heart. Both the triggering factors and the mechanisms involved in the abnormal formation of the insoluble fibrillar aggregates from the soluble proteins are poorly understood. For example, although the fibrillar deposits are typically found associated with the extracellular matrix and basement membranes, it is not clear whether fibrils are initially formed intra- or extracellularly, nor it is understood what determines where the deposits will occur; i.e., site tropism. In the present investigation, we studied the interaction of a recombinant amyloidogenic light-chain variable domain, SMA, with lipid vesicles. The nature of the interaction was dependent on the lipid composition and the SMA to lipid ratio. The most pronounced effect was found from vesicles composed of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine/1-palmitoyl-2-oleoyl-sn-glycero-3-phosphate, which dramatically accelerated fibril growth. Interestingly, spectral probes, such as intrinsic fluorescence and far-UV CD spectroscopy did not show significant conformational changes in the presence of the vesicles. The presence of cholesterol or divalent cations, such as Ca²⁺ and Mg²⁺, lead to decreased membrane-induced SMA fibrillation. Thus, membranes may have significant effects on light-chain fibrillation and may contribute to the site selectivity observed in AL amyloidosis.