Neutral Mucins Research Articles

Análise histológica e histoquímica de cistos intra-epiteliais de tubas uterinas de novilhas mestiças

Tubas uterinas de 21 novilhas mestiças Bos taurus taurus × Bos taurus indicus, em diferentes fases do ciclo estral natural (estro, metaestro e diestro) ou induzido pelo tratamento superovulatório (estro e metaestro superovulados), foram avaliadas quanto à presença de cistos intra-epiteliais e à caracterização histoquímica de seu conteúdo. Verificou-se a ocorrência de cistos intra-epiteliais nas tubas uterinas em todos os animais, mais freqüentes nas regiões do infundíbulo e ampola. Eles ocorreram nos lados direito e esquerdo, ipsi- e contralateral ao ovário ativo (folículo pré-ovulatório ou corpo lúteo), nas fases estrogênica e progesterônica do ciclo. No conteúdo cístico, houve predominância de mucinas neutras e ácidas carboxiladas, sendo as mucinas sulfatadas presentes em menor intensidade, e não se observou glicogênio. Os resultados sustentam a hipótese de que esses cistos formam-se pela fusão de luminações intracitoplasmáticas e/ou vacúolos ciliados do epitélio tubário.

Pepsinogen and H,K-ATPase mediate acid secretion in gastric glands of Triturus carnifex (Amphibia, Caudata)

The gastric glands of Triturus carnifex (Amphibia, Caudata) have been examined by histochemical and immunohistochemical methods with particular regard to hydrochloric acid and pepsinogen secretion. Fundic glands consist of mucous neck cells, endocrine cells and oxynticopeptic cells producing both pepsinogen and hydrochloric acid. The neck cells showed an unexpected distribution pattern which was only observed in the oral fundus, and produced neutral mucins with glycosidic residues of GalNAc and Gal beta1,3GalNAc, and in this respect they differ from the neck cells of anuran amphibians. The secretion of pepsinogen and hydrochloric acid as demonstrated by immunolabelling with anti-H,K-ATPase and with anti-pepsinogen, respectively, seems not to vary significantly along the longitudinal axis of the stomach. The mechanism of gastric acid secretion seems to be mediated by an ATPase, having similar features to the mammalian gastric H,K-ATPase, and is localised in the luminal membrane and in the subapical cytoplasm of the oxynticopeptic cells. Unusually, the same cytoplasmic areas revealed binding specificity for the winged pea lectin (WPA) from Lotus tetragonolobus, even after beta elimination, indicating the presence of fucosyl residues in N-linked oligosaccharidic chains in glycoproteins of beta-H,K-ATPase subunits.

Intraductal Tubular Adenoma of the Pancreas, Pyloric Gland Type

The intraductal tubular adenoma (ITA), pyloric gland type, of the pancreas is an uncommon benign tumor, akin to the pyloric gland type adenoma of the gallbladder. We report 6 cases of ITA of the pancreas: 3 male and 3 female aged 50 to 79 years (mean, 63.5 years; median, 65 years); all were examined clinicopathologically. Four patients showed no symptoms, but appetite loss and/or general fatigue presented in two. Grossly, all tumors formed a localized polypoid mass protruding into the lumen of the dilated pancreatic duct. Five of the six tumors were found within the main duct, and the other arose within the branch duct of the pancreas. Microscopically, the tumors were composed of closely packed tubular glands resembling pyloric type glands. They were lined by columnar or cuboidal epithelial cells with foci of mild to moderate dysplastic change. In 2 cases, the adjacent pancreas showed foci of intraductal papillary-mucinous adenoma. Histochemically, the tumors largely showed neutral mucin with a lesser amount of acidic mucin made up mainly of sialomucin. Endocrine cells were found in five tumors. Immunohistochemically, all tumors were labeled with M-GGMC-1 and MUC6, whereas MUC1 and MUC2 stains were negative. Pepsinogen II was positive in 5 tumors; thus, the results displayed a pattern of differentiation similar to those of ordinary gastric pyloric or metaplastic pyloric glands. DPC4 expression was maintained in all tumors and p53-positive nuclei were hardly encountered. All patients are alive with no evidence of disease 3 to 10.5 years after surgical resection.

Quantitative and qualitative alterations of intestinal mucins in BioBreeding rats

In diabetes-prone BioBreeding rats, an enteropathy often precedes the onset of auto-immune insulitis. The present study draws attention to quantitative and qualitative alterations of intestinal mucins in this animal model of type 1 diabetes mellitus. Male and female diabetes-resistant (BBc) and diabetes-prone (BBdp) BioBreeding rats fed, from one to two weeks after weaning onwards, either a plant-based diabetes-promoting diet (NTP) or a hydrolysed casein diabetes-protective diet (HC), were sacrificed at 11-14 weeks of age. Proteins and total mucins, as well as acid and neutral mucins, were measured in a segment of the intestinal tract, located 25-30 cm below the pylorus. No significant difference between BBc and BBdp rats was found when fed the HC diet. However, the NTP diet lowered both total and neutral mucins, whilst failing to affect significantly acidic mucins. The effects of the NTP diet were more pronounced in BBdp rats than in BBc rats. It is speculated that the quantitative and qualitative changes evoked by the NTP diet in BBdp rats may play a role in the alteration of gut permeability found under the same experimental conditions.

Histochemical Structure of the Mucus Gel Layer Coating the Fecal Surface of Rodents, Rabbits and Humans

The aim of this study was to investigate whether a mucus layer covers the surface of various animal feces and, if so, to show the structure and mucin composition of this layer. The freshly excreted feces of mice, rats, guinea pigs, rabbits and humans were fixed with Carnoy solution. Cross-sections approximately 5 microm thick were stained with alcian blue (AB) or the periodic acid Schiff (PAS) reaction. We measured the thickness of the mucus layer on the fecal surface of these sections. The fecal surface was covered with a continuous mucus layer in all specimens. The mucus layers of mice, rats and humans consisted of the alternate stratification of AB-positive and PAS-positive mucin layers. In contrast, the mucus layer consisted of an inner PAS-positive neutral mucin layer and an outer AB-positive acidic mucin layer in guinea pigs and rabbits. The average thicknesses of the mucus layers upon the fecal surfaces for mice, rats, guinea pigs, rabbits and humans were 19 +/- 12, 22 +/- 14, 15 +/- 4.6, 19 +/- 14 and 17 +/- 11 microm, respectively. These results demonstrated that the fecal surfaces are covered with continuous mucus layers in rodents, rabbits and humans, with substructures varying among species.

Ultrastructural and histochemical study on gills and skin of the Senegal sole, Solea senegalensis

This study was undertaken to identify the normal ultrastructural features of gills and skin of the Senegal sole, Solea senegalensis, for a comparative measure to morphological alterations caused by environmental stressors such as reduced water quality and diseases. In the Senegal sole skin, four morphologically distinct layers were identified: cuticle, epidermis, dermis and hypodermis. The epidermis was composed of stratified epithelium containing three cellular layers: the outermost or mucosa layer, the middle or fusiform layer and the stratum germinativum or the basal layer. In the mucosa, two mucous cell types were differentiated: type A cells containing several round vesicles of different electron density and type B cells containing mucosomes of uniform electron density. Senegal sole have five pairs of gill arches, each containing two rows of well-developed and compactly organized primary filaments and secondary lamellae. Fingerprint-like microridges were observed on the surface of epithelial cells. The branchial lamellae epithelium consisted of different cell types: pavement, mucous and chloride. Between the chloride cells and the larger pavement cells, accessory cells were observed. Complexes of tight junctions and desmosomes were frequently observed between adjacent chloride and epithelial cells. Neutral mucosubstances and/or glycoconjugates were observed in the epidermis, dermis and hypodermis of S. senegalensis skin. Proteins rich in different amino acids, such as arginine and cysteine, reacted negatively or weakly positive in the epidermis, dermis and hypodermis. In gills, some mucous cells responded weakly positive to periodic acid-Schiff (PAS) reaction but were strongly stained with Alcian Blue at pH 0.5, 1 and 2.5. When Alcian Blue pH 2.5–PAS reaction was performed, most mucous cells were stained blue (carboxylated mucins) and some mucocytes stained purple, indicating a combination of neutral and acid mucins. Proteins rich in cysteine-bound sulphydryl (-SH-) and cystine disulphide (-S-S-) groups were strongly detected in branchial and epidermal mucous cells, whereas lysine, tyrosine and arginine containing proteins showed very weak staining in both epidermal and branchial mucous cells. Protein reactions were strongly positive in the pillar cells, except for those rich in tryptophan, whereas the branchial cartilaginous tissue did not show an important reaction. The performed lipid reactions were negative in goblet and chloride cells. It is concluded from this study that ultrastructural and cytohistochemical features of the Senegal sole skin and gills may serve as control structures in both natural and aquaculture systems to monitor or detect environmental stress responses at the histological level.

The viscosity and glycoprotein biochemistry of salmonid mucus varies with species, salinity and the presence of amoebic gill disease

Fish mucus has previously been reported to change in appearance and composition among species and in response to changes in salinity and disease status. This study reports on the mucus viscosity and glycoprotein biochemistry of Atlantic salmon (Salmo salar L.), brown trout (Salmo trutta L.) and rainbow trout (Oncorhynchus mykiss Walbaum) in freshwater and seawater, both naive to and affected by amoebic gill disease (AGD). Cutaneous mucus viscosity was measured over a range of shear rates (11.5, 23, 46 and 115 s(-1)), and non-Newtonian behaviour was demonstrated for all three species. Mucus viscosity was significantly greater in seawater than in freshwater for all species, and significantly lower in AGD-affected Atlantic salmon and brown trout. Mucus glucose, total protein and osmolality data indicated that differences in viscosity due to salinity were mostly attributed to changes in mucus hydration, while differences due to disease were mostly attributed to changes in mucus composition. Trends in gill mucus cell histochemistry included shifts in glycoproteins from neutral mucins in freshwater to acidic mucins in seawater, and shifts towards neutral mucins, with an increase in mucus cell numbers, in response to AGD. Results suggested that Atlantic salmon and brown trout are more similar to one another in their mucus profile than to rainbow trout. Atlantic salmon and brown trout both exhibited a whole-body mucus response to AGD, whereas rainbow trout exhibited only a local gill response. Findings hold implications for fish physiology and pathology, and indicate that future fish-disease management strategies should be species and condition specific.

258 A phase I trial in patients with solid tumours using autologous dendritic cells loaded with mannan-conjugated recombinant MUC1 protein

Antigens such as ganglioside GD3, neutral glycolipid Lewisy (Ley) and mucins MUC1 and MUC2 are over-expressed on the cell surface of many tumors. We have shown previously that conjugation of antigens such as these to keyhole limpet hemocyanin (KLH) and the use of immunological adjuvant QS-21 is the optimal approach for inducing high titer IgM and IgG antibodies. These antibodies are able to bind with natural antigens on the tumor cell surface and mediate complement dependent cytotoxicity and/or antibody dependent cell mediated cytotoxicity. Immunization of patients with monovalent vaccines containing these and a variety of other antigens have demonstrated both the consistent immunogenicity and the safety of these vaccines. Now, in preparation for the use of polyvalent conjugate vaccines in the clinic, we have addressed for the first time with conjugate vaccines against cancer antigens several questions in the pre-clinical setting, including whether immunogenicity of the individual components is decreased in the polyvalent vaccine and issues relating to vaccine formulation and administration. We have immunized groups of mice with GD3–KLH, Ley–KLH, MUC1–KLH and MUC2–KLH conjugates and QS-21 separately or mixed and administered at one or four sites. High titer IgM and IgG antibodies were induced against each of the four antigens whether administered singly in separate mice, at separate sites in the same mice, or mixed and administered at a single site or at four sites, or administered subcutaneously (s.c.) or intraperitoneally (i.p.). These antibodies reacted specifically with the respective antigens and tumor cells expressing these antigens. There was no evidence of suppression of the antibody response against any one of the antigens by the presence of the other conjugates in the vaccine. Immunogenicity of the four individual antigens conjugated to KLH and QS-21 is not affected by mixing the four together and administering them at a single subcutaneous site.

Estudo da morfo e citodiferenciação da glândula submandibular remanescente de ratos após excisão parcial de um de seus lobos

Manter uma boa saúde depende, entre outros fatores, de um fluxo salivar adequado1-3. Os danos causados por obstrução, traumas ou remoção cirúrgica das glândulas salivares poderão acarretar alteração na produção salivar. Qualquer diminuição no fluxo salivar trará conseqüências danosas ao organismo. Desenvolveu-se este trabalho com o objetivo de aprofundar o conhecimento nos mecanismos que envolvem a regeneração da Glândula Submandibular (GSM) de ratos submetida à excisão parcial de um de seus lobos. FORMA DE ESTUDO: Experimental. MATERIAL E MÉTODO: Foram utilizadas lâminas referentes ao desenvolvimento glandular de ratos aos 15, 16, 17, 18 e 19 dias de vida fetal, e 20 ratos machos de 30 ou 60 dias. Após conveniente anestesia foi removido o terço inferior do lobo esquerdo da GSM de cada animal. Após a remoção, foram deixados a se recuperar por 2, 3, 7 e 15 dias. Nestes tempos determinados foram eutanaziados, as glândulas removidas, fixadas em Methacarn, incluídas em parafina, e cortes de 5 ¼m efetuados. Foi realizada coloração ou com hematoxilina/eosina ou com ácido Periódico Reativo de Schiff (PAS). RESULTADOS: Observou-se que o processo regenerativo se instalou precocemente e em todos os espécimes estudados. Foi semelhante ao aspecto verificado no desenvolvimento glandular normal e mais acentuado no rato de 30 dias. A citodiferenciação representada pela marcação das mucinas neutras pelo PAS foi discreta inicialmente, logo após atingindo sua produção máxima, então finalmente reduzindo a expressão, sendo mudada a sua localização inicial. CONCLUSÃO: Baseados nos resultados obtidos, concluiu-se que o processo regenerativo da GSM de ratos excisada é estável, permanente e gradual, seguindo etapas definidas.

Colonic expression of MUC2, MUC5AC, and TFF1 in inflammatory bowel disease in children.

The quantity and quality of mucins are affected in inflammatory bowel disease (IBD) both because of a reduction in the number of goblet cells and a decrease in the number of sugar residues per oligosaccharide side chain. Alteration in the types of mucins and aberrant location may contribute to the underlying pathology by affecting the mucus barrier function or may instead be a response to inflammation. The authors used the periodic acid-Schiff/Alcian blue stain to distinguish neutral and acidic mucins, and used specific antibodies to the mature goblet cell mucin MUC2, MUC2 core antigen, foveolar cell mucin MUC5AC, and gastric trefoil factor (TFF1), to characterize their presence and distribution in colonic tissue sections from patients with IBD. Both core and mature MUC2 were expressed in all colonic goblet cells from patients with ulcerative colitis (UC) and Crohn disease and from healthy controls. MUC5AC and TFF1, which are not normally expressed by colonic tissue, also were expressed in scattered goblet cells, coexpressing with MUC2. In areas of goblet cell depletion, MUC2 was present in cytoplasmic granules of flattened, cuboidal, nongoblet-cell-like surface cells. The staining was more intense and homogenous with the MUC2 core antibody, suggesting expression of relatively immature mucin. Some of these cells also coexpressed MUC5AC but to a lesser extent. These findings are not unique to IBD but were also found in other types of intestinal inflammation. The study confirms earlier observations that MUC2 is the major colonic mucin in IBD. It appears in two forms: mature MUC2 in goblet cells and immature MUC2 especially in secretory granules of cells that are not phenotypically goblet cells. MUC5AC and TFF1 expression in goblet cells is common in IBD and other inflammatory conditions of the colon. These changes may represent a nonspecific repair function of the colon cells to compensate for damage to barrier function.

Colonic Expression of MUC2, MUC5AC, and TFF1 in Inflammatory Bowel Disease in Children

ABSTRACTBackground:The quantity and quality of mucins are affected in inflammatory bowel disease (IBD) both because of a reduction in the number of goblet cells and a decrease in the number of sugar residues per oligosaccharide side chain. Alteration in the types of mucins and aberrant location may contribute to the underlying pathology by affecting the mucus barrier function or may instead be a response to inflammation. The authors used the periodic acid‐Schiff/Alcian blue stain to distinguish neutral and acidic mucins, and used specific antibodies to the mature goblet cell mucin MUC2, MUC2 core antigen, foveolar cell mucin MUC5AC, and gastric trefoil factor (TFF1), to characterize their presence and distribution in colonic tissue sections from patients with IBD.Results:Both core and mature MUC2 were expressed in all colonic goblet cells from patients with ulcerative colitis (UC) and Crohn disease and from healthy controls. MUC5AC and TFF1, which are not normally expressed by colonic tissue, also were expressed in scattered goblet cells, coexpressing with MUC2. In areas of goblet cell depletion, MUC2 was present in cytoplasmic granules of flattened, cuboidal, nongoblet‐cell–like surface cells. The staining was more intense and homogenous with the MUC2 core antibody, suggesting expression of relatively immature mucin. Some of these cells also coexpressed MUC5AC but to a lesser extent. These findings are not unique to IBD but were also found in other types of intestinal inflammation.Conclusion:The study confirms earlier observations that MUC2 is the major colonic mucin in IBD. It appears in two forms: mature MUC2 in goblet cells and immature MUC2 especially in secretory granules of cells that are not phenotypically goblet cells. MUC5AC and TFF1 expression in goblet cells is common in IBD and other inflammatory conditions of the colon. These changes may represent a nonspecific repair function of the colon cells to compensate for damage to barrier function.

Difference in cytoplasmic localization pattern of neutral mucin among lobular endocervical glandular hyperplasia, adenoma malignum, and common adenocarcinoma of the uterine cervix.

To investigate whether the cytoplasmic localization pattern of neutral mucin differs between lobular endocervical glandular hyperplasia (LEGH) and cervical adenocarcinoma (CxAd), including minimal-deviation adenocarcinoma (MDA), or adenoma malignum, alcian blue (pH 2.5)/periodic acid-Schiff (AB-PAS) staining was performed to formalin-fixed paraffin-embedded tissue sections of 13 lesions of LEGH and 53 tumors of CxAd, including 6 tumors of MDA. The cytoplasmic localization of neutral mucin was classified as a "whole cytoplasmic pattern," in which neutral mucin filled the cytoplasm entirely, or as an "apical pattern," in which neutral mucin was localized in the subsurface area only. Cytoplasmic neutral mucin patterns were detected in all 13 cases of LEGH and in 19 cases (36%) of CxAd, including five cases of MDA. The localization of neutral mucin was always the whole cytoplasmic pattern in 13 cases of LEGH, but was the apical pattern in these 19 cases of CxAd. The other 34 cases of CxAd, including 1 case of MDA, corresponded to the acid mucin pattern stained purple or blue or no staining pattern by AB-PAS. Among the 53 cases of CxAd, the apical neutral mucin pattern was an indicator of poorer patient prognosis by univariate and multivariate analyses. The examination of cytoplasmic localization of neutral mucin might be applicable, not only to differential diagnosis between LEGH and CxAd, including MDA, but also to estimate clinical aggressiveness of CxAd.

Cytokeratin profile and neuroendocrine cells in the glandular component of cardiac myxoma.

Glandular cardiac myxomas are very rare tumors of uncertain histogenesis that display glandular structures within otherwise typical myxomatous tissue. The origin of the glands has been attributed to epithelial differentiation of a totipotent cardiomyogenic precursor cell or to entrapped embryonal rests in the tumor. We studied four cases of glandular myxomas (three sporadic and one familial) to define the immunophenotypic profile of the glandular elements. The glands were either single and located within the myxoma cell islands (three cases) or in groups embedded in the myxomatous matrix. In the latter case, the glands featured villous projections, irregular profile, active inflammation or focal reactive cellular atypia (case 3) and had acidic and neutral mucins (mostly sialomucins). The cytokeratin expression profile (cytokeratin 7 and 20 co-expression) was similar to that of foregut derivatives. Scattered chromogranin-positive neuroendocrine cells were observed in case 3. Our findings indicate that the glandular component in cardiac myxoma is morphologically heterogeneous. In some cases, the scattered glands may derive from a divergent (epithelial) differentiation of myxoma cells; in others, entrapment of embryonic gastrointestinal rests (with mature neuroendocrine and mucous cell populations) could be the case.

Staining methods applied to glycol methacrylate embedded tissue sections

The use of glycol methacrylate (GMA) avoids some technical artifacts, which are usually observed in paraffin-embedded sections, providing good morphological resolution. On the other hand, weak staining have been mentioned during the use of different methods in plastic sections. In the present study, changes in the histological staining procedures have been assayed during the use of staining and histochemical methods in different GMA-embedded tissues. Samples of tongue, submandibular and sublingual glands, cartilage, portions of respiratory tract and nervous ganglion were fixed in 4% formaldehyde and embedded in glycol methacrylate. The sections of tongue and nervous ganglion were stained by H&E. Picrosirius, Toluidine Blue and Sudan Black B methods were applied, respectively, for identification of collagen fibers in submandibular gland, sulfated glycosaminoglycans in cartilage (metachromasia) and myelin lipids in nervous ganglion. Periodic Acid-Schiff (PAS) method was used for detection of glycoconjugates in submandibular gland and cartilage while AB/PAS combined methods were applied for detection of mucins in the respiratory tract. In addition, a combination of Alcian Blue (AB) and Picrosirius methods was also assayed in the sublingual gland sections. The GMA-embedded tissue sections showed an optimal morphological integrity and were favorable to the staining methods employed in the present study. In the sections of tongue and nervous ganglion, a good contrast of basophilic and acidophilic structures was obtained by H&E. An intense eosinophilia was observed either in the striated muscle fibers or in the myelin sheaths in which the lipids were preserved and revealed by Sudan Black B. In the cartilage matrix, a strong metachromasia was revealed by Toluidine Blue in the negatively-charged glycosaminoglycans. In the chondrocytes, glycogen granules were intensely positive to PAS method. Extracellular glycoproteins were also PAS positive in the basal membrane and in the region occupied by the lamina externa and reticular fibers surrounding each smooth muscle cells of the blood vessels. In the epithelial cells of the respiratory tract, acid and neutral mucins were histochemically detected by AB and PAS methods, respectively. Moreover, granules containing acid and neutral mucins were revealed in purple by AB and PAS concomitantly. In the sublingual gland sections, a distinct affinity of acid mucins by AB (in turquoise-blue) and collagen fibers by Picrosirius (in red) was obtained when these methods were combined. Although some routine dyes used in paraffin sections have showed a weak stain in historesin sections, our results showed that different dyes could be applied in GMA sections if modified staining procedures were assayed. Therefore, appropriate staining contrast and, thus, detection of one or different substances in a same section can be acquired in association to the good morphological resolution provided by GMA.

Structure and mucous histochemistry of the intestinal respiratory tract of the mud loach,Misgurnus anguillicaudatus(Cantor)

The straight intestinal tract of the mud loach Misgurnus anguillicaudatus was divided into an intestine and rectum which consisted of a mucosa (epithelial layer), lamina propria-submucosa, muscularis and serosa. The intestine and rectum have shorter mucosal folds and a thinner wall. Extensive vascular capillary networks were present in the mucosa of the intestine and the rectum. The diffusion distance between the vascular capillaries and the lumen in the intestinal and rectal mucosal epithelium was about 11.2 μm (±1.12). The majority of the epithelial mucous cells contain acidic mucins although there are small amounts of a mixture of acidic and neutral mucins. The intestinal tract of M. anguillicaudatus is probably modified to suit its role of respiration for the deficient oxygen supply within their environment.

Long-term evaluation of mice model infected with Helicobacter pylori: focus on gastric pathology including gastric cancer.

Long-term evaluation of gastric pathology after H. pylori infection is very important in order to reveal its clinical implications, since debate still exists on the gastric carcinogenesis provoked by H. pylori infection in animal models. Either to evaluate the long-term outcome of H. pylori infection or to determine how H. pylori could provoke gastric cancer in the mice model. Four-week-old specific pathogen free C57BL/6 mice (n = 115) were infected with SS1, the mouse-adapted H. pylori strain. After 4, 8, 16, 24, 36, 50 and 80 weeks of bacterial infection, the H. pylori-infected mice were sacrificed. After 80 weeks of infection, almost all the H. pylori-infected mice developed hyperplastic gastritis, but did not show any evidence of gastric adenoma, dysplasia or carcinoma. PCNA positive cells were most abundant after 50 weeks and tended to decrease thereafter up to 80 weeks, whereas apoptosis began to be noted 8 weeks after H. pylori infection, showing 7-8 apoptotic cells/high power field, and tending to increase as time passed. Normally observed neutral mucin decreased during the experiment, showing the most marked decrease 50 weeks after H. pylori infection. In contrast, acidic mucin was noted from 50 weeks after infection. The SS1-infected mouse seems to be a suitable animal model for H. pylori-related research, and H. pylori itself does not induce gastric cancer in normal wild-type mouse model following long-term exposure, which could be explained by the balance that exists between cell proliferation and apoptosis.

Fructans in the diet cause alterations of intestinal mucosal architecture, released mucins and mucosa-associated bifidobacteria in gnotobiotic rats.

The effects of fructans in the diet on the mucosal morphometry (height of villi, depth of the crypts, number of goblet cells), the thickness of the epithelial mucus layer and the histochemical composition of intestinal mucosubstances in the distal jejunum and the distal colon were investigated by comparing germ-free (GF) rats, rats harbouring Bacteroides vulgatus and Bifidobacterium longum (diassociated (DA) rats), and rats with a human faecal flora (HFA). The rats were fed either a commercial standard diet (ST) or ST + (50 g oligofructose (OF)-long-chain inulin (lcIN))/kg. Changes in total bacteria, bifidobacteria and Bacteroides-Prevotella in response to feeding these diets were investigated by fluorescent in situ hybridization with 16S rRNA-targeted probes both in intestinal contents (lumen bacteria) and tissue sections (mucosa-associated bacteria). The OF-lcIN-containing diet resulted in higher villi and deeper crypts in bacteria-associated, but not in GF rats. In DA and HFA rats, the colonic epithelial mucus layer was thicker and the numbers of the goblet cells were greater than in GF rats. These effects were enhanced by the OF-lcIN-containing diet. In both dietary groups, bacterial colonization of GF rats caused an increase in neutral mucins in the distal jejunum and colon. Bacteria-associated rats had more acidic mucins in the colon than GF rats, and the OF-lcIN-containing diet stimulated sulfomucins as the predominant type of acidic mucins, while sialomucins dominated in the ST-fed groups. The number of mucosa-associated bifidobacteria detected in the colon of DA and HFA rats was greater with OF-lcIN than ST (4.9 and 5.4 v. 3.5 and 4.0 log10/mm2 mucosal surface respectively), whereas the number of luminal bifidobacteria was only affected by fructans in DA rats. Bacteroides did not differ between the groups. The stabilisation of the gut mucosal barrier, either by changes in the mucosal architecture itself, in released mucins or by stimulation of mucosal bifidobacteria with fructans, could become an important topic in the treatment and prophylaxis of gastrointestinal disorders and health maintenance.

Pre- and posthatch development of goblet cells in the broiler small intestine: effect of delayed access to feed

Mucin glycoproteins play a key role in the regular function of the epithelium of the gastrointestinal tract, and in this study, the ontogenesis and development of mucin producing cells was examined in the broiler. Mucin-producing cells were observed in the small intestine from 3 d before hatch, and at this time contained only acidic mucin. After hatch and until Day 7 posthatch, the proximal, middle, and distal segments of the small intestine contained similar proportions of goblet cells producing acidic and neutral mucins. A gradient of goblet cell density was observed increasing along the duodenal to ileal axis. Delayed access to feed for 48 h posthatch resulted in an increase in intestinal intracellular mucins, which might have been due to impaired mucin secretion or enhanced mucin production. Changes in mucin dynamics could affect absorptive and protective functions of the small intestine.

Morphological, morphometric and histochemical characterization of the gastric mucosa of the camel (Camelus dromedarius).

Mucosal morphology, morphometry and mucin histochemistry of the stomach were studied in the one-humped camel. The lining of the stomach was divided into eight grossly identifiable regions. The first region was non-glandular, occupied the body of the first compartment of the stomach and constituted 53.2% of the gastric mucosa. The other seven regions were lined by a glandular mucosa. Histological, histochemical and morphometric investigations have shown that glandular mucosa comprises pseudo-cardiac, cardiac, fundic and pyloric regions. The pseudo-cardiac region was characterized by widely separated short tubular serous glands. It constituted 36.2% of the gastric mucosa; it extended over the entire lining of the second compartment and parts of the first and third compartments. The cardiac region was confined to the initial zone of the third compartment amidst the psuedo-cardiac region but contiguous with the distal end of the gastric groove. It constituted 3.4% of the gastric mucosa and was characterized by neutral and acid mucin positive glands. The fundic and pyloric regions occupied the distal distended part of the third compartment. The fundic region constituted 4.3% of the gastric mucosa. It was packed with typical fundic glands characterized by chief cells, parietal cells and acid mucin positive neck cells. The pyloric region constituted 2.9% of the gastric mucosa. Its glands were positive to acid mucins except for their bases that were positive to neutral mucins. Differences in volume densities of the mucosal components and reactivity of the surface epithelium and gastric pits to mucin stains were noted in the different regions of the stomach.

A simple method to demonstrate duodenal gastric metaplasia

The diagnosis of duodenal gastric metaplasia (DGM) is based on the demonstration of periodic acid Schiff (PAS) positive mucin in duodenal columnar cells. Recently, groups of duodenal columnar cells were seen to be autofluorescent in haematoxylin and eosin (H&E) stained sections from a patient with DGM. Consecutive archival gastric and duodenal H&E sections from 30 patients with chronic gastritis and DGM (CG+DGM), from 30 with chronic gastritis without DGM (control group I), from 30 with normal gastric and duodenal mucosa (control group II), and from five patients with coeliac disease (control group III) were reviewed on a fluorescent microscope. The surface epithelium of the gastric mucosa in all 95 cases had autofluorescent material. In 31 cases with DGM (including one unreported case in control group I), groups of columnar duodenal cells also had autofluorescent material. In the remaining 64 cases, duodenal columnar cells were not autofluorescent. Results were confirmed with the PAS stain. The method described detected apical mucin secretion in columnar cells, both in the stomach and in the duodenum from patients with DGM. The autofluorescence was induced by eosin (which binds to neutral mucin). Observing H&E stained duodenal biopsies under a fluorescence microscope may be sufficient to confirm DGM or to detect incipient DGM. Despite long observation periods and a long exposure time while photographing, the autofluorescence did not fade away. Because re-cuttings for special staining (PAS) are no longer required when this method is used, both final diagnosing time and laboratory costs can be reduced.