Pig intestinal epithelium undergoes a complete renewal every 2 to 3 days that is driven by intestinal stem cells (ISCs) located at the crypt base in their niche. Intestinal stem cells generate a pool of highly proliferative transit-amplifying cells, which either migrate up the villus and differentiate into enterocytes and secretory cells or migrate towards the base of the crypt where they differentiate into Paneth cells that secrete antimicrobial peptides. The balance between ISCs’ self-renewal and differentiation controls intestinal epithelial homeostasis; therefore, ISCs are essential for ensuring intestinal epithelial integrity. Detailed knowledge of these mechanisms in pig and other domestic species is very limited. Therefore, the aim of this work was to characterize ISC from birth to weaning. We analysed the duodenum, jejunum and colon of six piglets at birth, 6-day-old nursing piglets and 28-day-old weanlings, one week after weaning. We immunolocalized homeobox only protein+ (HOPX) and sex-determining region Y-box 9+ (SOX9) cells that identify quiescent and active ISC, respectively. The volume of ISCs was quantified with stereological methods and was compared to that of mitotic cells expressing proliferating cell nuclear antigen and apoptotic cells identified by the presence of cleaved caspase-3. Furthermore, we compared all these values with crypts and villi measurements and their ratio. Our results indicated that both quiescent and active ISCs are present in pig intestine from birth to weaning and are localized in the crypts of the small and large intestine. However, both markers were also observed along the villi and on the colon luminal epithelium, suggesting that at these stages, pig mucosa is still immature. Weaning induced a dramatic reduction of both HOPX+ and SOX9+ cells, but SOX9+ cells underwent a significantly greater reduction in the small intestine than in the colon. This suggests that the two ISC types are differentially regulated along the intestinal tracts. Overall, the pig ISC complex has many similarities with its murine counterpart, but also has some differences. These include active ISC not showing the typical columnar base morphology as well as the absence of bona fide Paneth cells. This is the first description of ISC dynamics during pig’s early life and provides useful reference data for future studies, aimed at targeting ISC for the development of efficient alternatives to in-feed antibiotics for preserving intestinal integrity.

The rapid shift to high-grain (HG) diets in ruminants can affect the function of the rumen epithelium, but the dynamic changes in the composition of the epithelium-associated (epimural) bacterial community in sheep still needs further investigation. Twenty male lambs were randomly allocated to four groups (n = 5). Animals of the first group received hay diet and represented a control group (CON). Simultaneously, animals in the other three groups (HG groups) were rapidly shifted to an HG diet (60% concentrate)which continued for 7 (HG7), 14 (HG14) and 28 (HG28) days, correspondingly. Results showed that ruminal pH dramatically decreased due to the rapid shift to the HG diet (P <0.001), while, the concentrations of butyrate (P <0.001), lactate (P = 0.001), valerate (P = 0.008) and total volatile fatty acids (P = 0.001) increased. Diversity estimators showed a dramatic decrease after the shift without recovering as the HG feeding continued. The principal coordinates analysis showed that CON group clustered separately from all HG groups with the presence of significant difference only between HG7 and HG28 (P = 0.034). The non-parametric multivariate analysis (npmv R-package) deduced that the primary significant differences in phyla and phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt)-predicted Kyoto Encyclopedia of Genes and Genomes (KEGGs) was attributed mainly to the diet composition (P <0.001, P = 0.001) compared to its application period (P = 0.140, 0.545) which showed a significant effect only on the genus (P = 0.001) and the operational taxonomic units (OTUs) level (P = 0.011). The Kruskal–Wallis test deduced that six phyla showed a significant effect due to the shift in diet composition. At the genus level, HG feeding altered the abundance of 12 taxa, four of which showed a significant variation due to the duration of the HG diet application. Similarly, we found that 21 OTUs showed significant variations due to the duration of the HG diet application. Furthermore, the genes abundance predicted by PICRUSt revealed that the HG feeding significantly affected seven metabolic pathways identified in the KEGG. Particularly, the abundance of gene families associated with carbohydrates metabolism were significantly higher in HG feeding groups (P = 0.027). Collectively, these results revealed that the rapid transition to an HG diet causes dramatic alterations in ruminal fermentation and the composition and function of ruminal epithelium-associated microbiome in sheep, while, the duration of the HG diet application causes drastic alterations to the abundance of some species.

Due to their high energy requirements, high-yielding dairy cows receive high-grain diets. This commonly jeopardises their gastrointestinal health by causing subacute ruminal acidosis (SARA) and hindgut acidosis. These disorders can disrupt nutrient utilisations, impair the functionalities of gastrointestinal microbiota, and reduce the absorptive and barrier capacities of gastrointestinal epithelia. They can also trigger inflammatory responses. The symptoms of SARA are not only due to a depressed rumen pH. Hence, the diagnosis of this disorder based solely on reticulo-rumen pH values is inaccurate. An accurate diagnosis requires a combination of clinical examinations of cows, including blood, milk, urine and faeces parameters, as well as analyses of herd management and feed quality, including the dietary contents of NDF, starch and physical effective NDF. Grain-induced SARA increases acidity and shifts availabilities of substrates for microorganisms in the reticulo-rumen and hindgut and can result in a dysbiotic microbiota that are characterised by low richness, diversity and functionality. Also, amylolytic microorganisms become more dominant at the expense of proteolytic and fibrolytic ones. Opportunistic microorganisms can take advantage of newly available niches, which, combined with reduced functionalities of epithelia, can contribute to an overall reduction in nutrient utilisation and increasing endotoxins and pathogens in digesta and faeces. The reduced barrier function of epithelia increases translocation of these endotoxins and other immunogenic compounds out of the digestive tract, which may be the cause of inflammations. This needs to be confirmed by determining the toxicity of these compounds. Cows differ in their susceptibility to poor gastrointestinal health, due to variations in genetics, feeding history, diet adaptation, gastrointestinal microbiota, metabolic adaptation, stress and infections. These differences may also offer opportunities for the management of gastrointestinal health. Strategies to prevent SARA include balancing the diet for physical effective fibre, non-fibre carbohydrates and starch, managing the different fractions of non-fibre carbohydrates, and consideration of the type and processing of grain and forage digestibility. Gastrointestinal health disorders due to high grain feeding may be attenuated by a variety of feed supplements and additives, including buffers, antibiotics, probiotics/direct fed microbials and yeast products. However, the efficacy of strategies to prevent these disorders must be improved. This requires a better understanding of the mechanisms through which these strategies affect the functionality of gastrointestinal microbiota and epithelia, and the immunity, inflammation and ‘gastrointestinal-health robustness’ of cows. More representative models to induce SARA are also needed.

The importance of the use of exogenous butyrate in calves’ diets is due to its role as a factor stimulating the functional development of ruminal epithelium and improving calf performance during the transition from preruminant to ruminant status. Our review will first present results related to effects of the administration of butyrate in calves’ diets on the development of ruminal epithelium toward a more effective absorption and metabolism of fermentation products from the rumen. The introduction of sodium butyrate at a level of about 0.3% of diet dry matter is accompanied by an increase to 35% in butyrate concentration in the rumen of 33-day-old calves. Mutual reliance between an enhanced ruminal concentration of butyrate and the activities of transcription factors, genes and proteins involved in cell proliferation, ketogenesis and the maintenance of cell pH homeostasis in the ruminal epithelial cells has been clearly confirmed in many experiments. Second, the review presents results related to the effects of the introduction of butyrate salts in the diet on calf performance. Of 11 studies a positive effect was found in six; five of these were obtained from the calves that started receiving butyrate supplement at a level of about 0.3% diet dry matter from the age of 3 to 5 days. Results indicate that when a supplement is given to calves soon after birth the functional development of ruminal epithelium in cooperation with the endocrine and digestion systems is transferred into improving the efficiency of rearing. There have been no studies on the effects of greater amounts of butyrate salts in milk replacer; butyrate constitutes about 1.2% of the whole cow’s milk dry matter. In older calves, when butyrate administration is provided as a component of a starter concentrate at the increasing inclusion rate from 0.3% to 3.0%, the practical effect in calf performance relates to the risk of depression of rumen pH below 5.5 and accompanying disruption of the organization of the ruminal epithelial tissue. The higher risk is noted in calves received starter with substantial content of a rapidly degradable starch. At present, the insufficient number of positive results confirming the beneficial effect of butyrate supplements in terms of an improvement in performance does not allow their recommendation for use in the practical feeding of calves.

Laryngeal premalignancy is a common clinical concern. While tobacco has long been established as the principal identifiable aetiological factor, the last two decades have seen publications investigating a potential role for gastroesophageal reflux, gastrectomy and human papilloma virus. Furthermore, there have been major advances in our understanding of the molecular biology of cancer and premalignancy. Accompanying this increased understanding, significant efforts have been made to correlate the expression of molecular markers with the clinical course of premalignant laryngeal lesions.

This review summarizes current knowledge of the aetiological factors and molecular biology of laryngeal premalignancy. All aetiological factors, including molecular markers, are discussed separately and their possible role in the clinical course of these lesions is discussed.

Tissue-specific stem cells play a key role in organ homoeostasis. They are relatively well characterized in systems which undergo constant proliferation and production of differentiated cells, including the haemopoietic system, skin and intestine. However, little is known about the role and regulation of stem cells in the mammary gland. This review briefly summarizes the current understanding of the role of breast-specific stem cells in normal and cancerous tissues, and how this may identify new targets for breast cancer prevention and therapy.

The purpose of the present study was to evaluate the biological behaviour of the marginal epithelium, that proliferates and eventually covers laryngeal granulomas, and to reveal the applicability of the recently re-introduced Ljubljana classification when reporting reactive epithelial hyperplastic lesions.

A retrospective clinical and histomorphological analysis was performed on 149 laryngeal granuloma biopsies. Epithelial changes were classified according to the Ljubljana classification into normal epithelium; simple, abnormal, or atypical hyperplasia; and carinoma in situ. Atrophic epithelium, not evaluated separately in the Ljubljana classification, was additionally assessed. Simple hyperplasia was found in 98 cases (65.8 per cent), abnormal hyperplasia in seven (4.7 per cent), atrophic epithelium in 24 (16.1 per cent), and normal squamous epithelium in 20 (13.4 per cent). Atypical hyperplasia and carcinoma in situ were not observed.

The results of our study clearly showed that the proliferation of the covering epithelium mostly in the form of simple hyperplasia, is entirely reactive and therefore reversible. No epithelial hyperplastic lesions were found that were previously described to be associated with an increased risk of malignant alteration, namely atypical hyperplasia and carcinoma in situ. However, since an initial growth of an invasive malignant neoplasm might macroscopically imitate the appearance of laryngeal granuloma, a histological examination in all aetiological forms of laryngeal granulomas is required. By clearly discerning the benign nature of epithelial changes in laryngeal granulomas, the recently re-evaluated and further formulated Ljubljana classification may also influence the clinical handling of patients.

Changes in vaginal epithelium are known to occur during the normal oestrous or menstrual cycle and in ovariectomised animals in response to various hormones. However, vaginal changes due to exogenous gonadotrophins superimposed on the normal hormonal milieu as occurs in in vitro fertilisation programmes have not previously been demonstrated. Female rats were hyperstimulated with follicle stimulating hormone and human chorionic gonadotrophin prior to mating. Control mated animals were not injected. Vaginal tissue was collected at 4.5, 5.5 and 6.5 d after mating. Tissue was processed for light microscopy. Hyperstimulation by the exogenous gonadotrophins caused mucification, a decrease in the number of epithelial layers and an increase in the thickness of the epithelium on d 4.5 of pregnancy. The mitotic index of the epithelial cells was depressed in the hyperstimulated rats with respect to control animals. Exposure to high levels of oestradiol and an altered progesterone[ratio ]oestradiol ratio appear to have caused the changes in the vaginal epithelium.

The aim of this study was to determine the degree to which the epidermis and oral epithelium of species other than man express cytokeratin (CK) intermediate filaments, which are markers of epithelial differentiation. Fixed, wax-embedded samples of skin, buccal mucosa and gingiva from rhesus monkey, marmoset, cow, sheep, pig, ferret, hamster, axolotl and trout were tested for CK expression using a panel of antihuman CK antibodies and an immunoperoxidase procedure. Human skin and oral mucosa were also stained to act as positive control. The results showed that antihuman CK antibodies stained animal tissues, but the patterns of staining were not always identical to the established human CK profile. Of particular interest was the expression of CK18, typically only detected in ‘simple’ epithelium in man, in bovine, ferret and hamster stratified epithelium from different sites. However, there was evidence of variable anti-CK antibody cross-reactivity, both as a result of intrinsic variations in CK polypeptide structure and as artifacts of fixation. We conclude that some CK are conserved between species, but that biological variables, for example local functional requirements, and technical factors affect the results. These considerations need to be borne in mind in animal studies of epithelial differentiation employing CK immunohistochemistry. Biochemical characterisation is ultimately necessary to determine specific differences between human and animal CK.

Twenty patients who had undergone open cavity mastoidectomy for chronic middle ear disease were selected for study. Following initial microscopic aural toilet, each cavity was painted in its medial aspect with a marker solution of Bonney's Blue dye. Each patient was assessed at weekly intervals for a minimum of three months following application of dye, and a photographic record made of the cavity. Information was also sought regarding the clinical behaviour of the mastoid cavities, with particular regard to degree of otorrhoea, and accumulation of debris. Migration of epithelium inferred by visible movement of dye occurred in 17 of the 20 mastoid cavities. In all these cases migration occurred in a medial to lateral direction, towards the exterior. In two cases there was no visible migration throughout the period of observation, and inspection after six months revealed the dye to be still present in the original position. Both these cases were of dry trouble-free cavities in which accumulation of debris did not appear to be a problem. This finding calls into question the assumption that clean trouble-free cavities are maintained by a satisfactorily functioning epithelial migration. In the four cavities which suffered from intermittent otorrhoea, epithelial migration occurred at a similar rate to that in dry cavities.

The distribution and abundance of mast cells in nasal polyps, the maxillary sinus mucosa of patients with sinusitis and the turbinate mucosa of allergic rhinitis was microscopically examined using different methods of fixation. In the epithelium of the surface and the ducts of nasal polyps (n = 8), the mean number of mast cells was over 20,000 per mm3 using Mota's fixation and the increase was correlated with the epithelial thickness (P<0.05). On the other hand those of the maxillary sinus mucosa (n = 6) and the nasal turbinate mucosa (n = 7) were less than 6,000 per mm3. In the subepithelial layer or areas deeper than the area with the glands, however, mast cell counts were less than 3,200 per mm3 in all diseases. More than 70–90 per cent of all mast cells in the epithelium of the mucosal surface and the ducts of the polyp, the maxillary sinus mucosa and nasal turbinates were formalin sensitive. Most of the mast cells in the subepithelial and deeper areas were formalin resistant in all diseases.

These results suggest that conditions for mast cell growth differ between polyps and the other diseases, and that the conditions which affect mast cells may contribute to polyp development.

The structure and function of the male accessory reproductive gland system of the cotton stainer, Dysdercus fasciatus Signoret, was studied using ultrastructural techniques. The gland system is composed of a pair of mesadenia and an ejaculatory duct, whose anterior end is swollen and encloses a glandular structure whose origin is not clear. Each mesadene is composed of a large number of sacs whose lumina are confluent. The epithelium of each sac is one cell layer thick and is composed of two cell types, mononucleate and multinucleate cells. The origin and siginficance of the multinucleate condition in the mesadenial epithelial cells is not clear, but it is suggested that this condition might have arisen during maturation, when mitotic divisions are complete, but the nuclei continued to multiply within an increased cytoplasmic mass, which itself does not divide.