Immunohistochemical demonstration of carbonic anhydrase isoenzyme VI (CA VI) expression in rat lower airways and lung.

Carbonic anhydrase isoenzyme VI (CA VI), which is transported in high concentrations in saliva and milk into the alimentary tract, is an important element of mucosal protection in the upper alimentary tract. Like alimentary tract mucosa, the respiratory tract mucosa is also exposed to heavy microbial, physical, and chemical stress. The protective and renewal-promoting factors present in the surface mucus of the respiratory tract are mainly produced by the seromucous tracheobronchial glands. Here we studied the secretion of CA VI by these glands in adult and developing rats using immunohistochemical techniques. The serous acinar and duct cells of the tracheobronchial glands stained for CA VI. The presence of the enzyme also in the duct content indicates its active secretion into the surface mucus. CA VI was also visible in the secretory cells and at the base of the ciliated cells of the tracheobronchial surface epithelium. Moreover, the Clara cells of the bronchiolar surface epithelium stained for CA VI. These findings are consistent with the hypothesis that CA VI has a mucosa-protective role not only in the gastrointestinal tract but also in the respiratory tract, where CA VI may act as a pivotal pH neutralizer and growth factor.     

The organization of serotonin-, dopamine-, and FMRFamide- containing neuronal elements and their possible role in the regulation of spontaneous contraction of the gastrointestinal tract in the snail Helix pomatia

Summary The distribution of serotonin-, tyrosine hydroxylase-, and FMRFamide-immunoreactive neuronal elements, as well as the concentrations of serotonin and dopamine in the different parts of the gastrointestinal tract, were studied in the snail Helix pomatia. The sensitivity of the spontaneous contractions of the alimentary tract to serotonin, dopamine, and FMRFamide was also tested. Serotonin-, tyrosine hydroxylase-, and FMRFamide-immunoreactive elements could be demonstrated in each part of the gastrointestinal tract, but they showed different innervation patterns. Serotonin- and tyrosine hydroxylase-immunoreactive elements were dominant in the submucosal layer, whereas FMRFamide-immunoreactive elements were dominant in both the mucosal and submucosal layers. Tyrosine hydroxylase-immunoreactive elements were confined to the longitudinal muscle trabeculae of submucosa, whereas serotonin-immunoreactive elements were distributed throughout the submucosal layer. No serotonin-immunoreactive cell bodies, but only fibers, could be detected in the gastrointestinal tract, and therefore they represent extrinsic elements. Tyrosine hydroxylase- and FMRFamide-immunoreactive cell bodies represent intrinsic elements of the tract. The occurrence and density of the serotonin- and tyrosine hydroxylase-immunoreactive elements showed significant differences in the different parts of the alimentary tract, in accordance with HPLC assays, which revealed a significant frontocaudal decrease in both the serotonin (from 2.11 to 1.21 pM/mg) and dopamine (from 3.28 to 0.52 pM/mg) contents of the different parts of the alimentary tract. Dopamine at 10-5 M concentration proved to be effective only on the longitudinal muscles by increasing the tone and frequency of contractions, but was ineffective on the circular muscles. Serotonin affected both the longitudinal and circular muscles. Serotonin at 10-5 M concentration decreased the tone and increased the frequency of low-amplitude contractions of the longitudinal muscles of the esophagus and the gizzard but increased both the tone and frequency of the crop. Serotonin at 10-9 M concentration slightly decreased the tone and blocked the contractions of the circular muscles in the crop but at 10-5 M concentration induced contractions of the circular muscles in the gizzard. FMRFamide at 10-6 M concentration decreased the tone and was shown to block the contractions of both the longitudinal and circular muscles.     

Cell-specific expression of mitochondrial carbonic anhydrase in the human and rat gastrointestinal tract.

Mitochondrial carbonic anhydrase V (CA V) in liver provides HCO3- to pyruvate carboxylase for the first step in gluconeogenesis and HCO3- to carbamyl phosphate synthetase I for the first step in ureagenesis. Because carbamyl phosphate synthetase I and ornithine transcarbamylase are also expressed in enterocytes, we tested the hypothesis that CA V is expressed in the gastrointestinal tract in addition to liver. Polyclonal rabbit antisera were raised against a polypeptide of 17 C-terminal amino acids of human CA V and against purified recombinant mouse isozyme and were used in Western blotting and immunoperoxidase staining of human and rat tissues. Immunohistochemistry showed that CA V is expressed cell-specifically in the alimentary canal mucosa from stomach to rectum. Immunoreactions for CA V were detected in the parietal cells and gastrin-producing G-cells of the stomach and in intestinal enterocytes. Western blotting of human and rat gastrointestinal tissues with isozyme-specific antibodies showed positive signals for CA V with the expected molecular mass. The findings in human tissues paralleled those in rat. The cell-specific pattern of CA V expression suggests a role for CA V in alimentary canal physiology. We propose that mitochondrial CA V participates in the detoxification of ammonia produced in the gastrointestinal tract by providing bicarbonate to carbamyl phosphate synthetase I. (J Histochem Cytochem 47:517-524, 1999)     

Histological and immunohistochemical studies of the endocrine cells of the gastrointestinal mucosa of the toad (Bufo regularis)

Using histological and immunhistochemical techniques, nine endocrine cell types were observed in the mucosa of the gastrointestinal tract of the toad, Bufo regularis, viz. enterochromaffin, somatostatin, glucagon, pancreatic polypeptide (PP), secretin, gastric inhibitory peptide (GIP), gastrin-C-terminal pentapeptide (GTPP), neurotensin and bombesin cells. The enterochromaffin cells were distributed throughout the gastrointestinal tract except the rectum. Somatostatin, glucagon, PP, secretin, GIP and GTPP cells were observed both in the stomach and in the small intestine. Neurotensin cells were seen only in the ileum and bombesin cells only in the pyloric and antral parts of the stomach. Immunostaining of consecutive sections did not reveal more than one polypeptide hormone in any of these cell types. It is concluded from the present results that the toad gastrointestinal mucosa contains endocrine cell types that are more or less homologous to those in the mammal alimentary tract, though some of them exhibit a different topographic distribution.     

Tritiated glycerol triether as an oil phase marker in man

3H-labeled glycerol triether has been suggested as a marker of the oil phase during digestion and absorption of a lipid test meal. This study examines the behavior of this isotope in the human alimentary tract. The results suggest that it is completely recovered from the gastrointestinal tract, and thus it remains solely with the oil phase of emulsions in vivo and with the oil phase of intestinal aspirates. (3)H-labeled glycerol triether may thus be an appropriate marker of the oil phase for use in human studies of lipid absorption.     

Histological and immunohistochemical studies of the endocrine cells of the gastrointestinal mucosa of the toad (Bufo regularis)

Summary Using histological and immunhistochemical techniques, nine endocrine cell types were observed in the mucosa of the gastrointestinal tract of the toad,Bufo regularis, viz. enterochromaffin, somatostatin, glucagon, pancreatic polypeptide (PP), secretin, gastric inhibitory peptide (GIP), gastrin-C-terminal pentapeptide (GTPP), neurotensin and bombesin cells. The enterochromaffin cells were distributed throughout the gastrointestinal tract except the rectum. Somatostatin, glucagon, PP, secretin, GIP and GTPP cells were observed both in the ileum and bombesin cells only in the pyloric and antral parts of the stomach. Immunostaining of consecutive sections did not reveal more than one polypeptide hormone in any of these cell types. It is concluded from the present results that the toad gastrointestinal mucosa contains endocrine cell types that are more or less homologous to those in the mammal alimentary tract, though some of them exhibit a different topographic distribution.     

Optical Coherence Tomography Identifies Lower Labial Salivary Gland Surface Density in Cystic Fibrosis

The labial minor salivary glands (LSGs) are easily accessible mucus-secreting structures of the alimentary tract that may provide new information on the basis of gastrointestinal complications of cystic fibrosis (CF). It was shown that they are destructed in the course of cystic fibrosis. We employed wide-field, micrometer resolution in vivo optical coherence tomography to assess the surface density of LSGs in 18 patients with CF and 18 healthy subjects. The median LSGs’ surface densities in CF patients, and in the control group were 4.32 glands/cm² and 6.58 glands/cm², respectively (p = 0.006; Mann-Whitney U test). A lower LSG surface density is a previously unrecognized CF-related pathology of the alimentary tract.     

The implication of adiponectin and resistin in gastrointestinal diseases

Adiponectin and resistin, members of the adipokine family, are multi-task hormones involved in several disorders, including those of the alimentary tract. In the present review, eligible studies focusing on the role of adiponectin and resistin in gastrointestinal diseases are manifested together and classified according to anatomic criteria. In addition, similarities and common patterns have been recognized, ultimately revealing an inverse association: the down-regulation of adiponectin and up-regulation of resistin - both in vitro and in vivo - in gastrointestinal disorders, irrespective of their diverse nature - inflammatory, autoimmune or malignant - or anatomic position - esophageal, gastric, of the small intestine, colonic. Finally, a potential role for both adipokines in alimentary tract-related carcinogenesis has been identified, possibly representing a missing link between obesity and cancer.     

美国白蛾幼虫消化道形态和超微结构观察

美国白蛾Hyphantria cunea Drury是我国重要的林业检疫性害虫之一,世界范围内寄主多达600余种,对我国林业生产和生态环境建设造成了巨大损失。明确美国白蛾幼虫消化道各部分的形态结构,可为进一步研究其幼虫的食性及消化机能奠定基础。利用光学显微镜、扫描电子显微镜与透射电子显微镜观察了美国白蛾6龄幼虫消化道形态及超微结构。美国白蛾幼虫的消化道由前肠、中肠、后肠组成。前肠是消化道最长的部分,占整个消化道的54.27%,包括咽、食道、嗉囊、前胃四部分;中肠较短,占整个消化道的21.28%,内部具围食膜;后肠由幽门、回肠、结肠和直肠组成,幽门由幽门锥和幽门瓣组成。马氏管共6条,丝腺2条。美国白蛾幼虫消化道总体结构大部分鳞翅目消化道结构相似,但是其前肠在长度上发生了较大的变异,本文进一步讨论了美国白蛾幼虫消化道结构与其食性及耐饥饿能力等的相关性。     

Dissemination of yeasts after gastrointestinal inoculation in antibiotic-treated mice

Mice pretreated with antibiotics were inoculated intragastrically with different yeast isolates to determine whether the resulting disruption of the normal flora ecology would allow certain fungi to colonize and disseminate from the gastrointestinal tract. Antibiotic treatment decreased the total population levels of the indigenous bacterial flora, and predisposed mice to gastrointestinal overgrowth and subsequent dissemination by Candida albicans, C. parapsilosis, C. pseudotropicalis, C. tropicalis, and Torulopsis glabrata. A clinical isolate of Rhodotorula rubra, on the other hand, was unable to maintain a stable population in the gut of similar mice and could not be isolated from systemic organs. Control animals not receiving antibiotic therapy, challenged with C. albicans, showed significantly lower gut population levels of yeasts, and Candida organisms could not be grown from visceral organs. It is suggested that suppression of fungi within the gastrointestinal tract by members of the normal bacterial flora may be an important mechanism whereby fungi are confined to the alimentary tract.     

Digestion of zooplankton in the alimentary tract of vendace (Coregonus albula) larvae

The degradation of zooplankton eaten by vendace larvae was investigated by cutting their tubiform alimentary tract into four quarters and analysing the contents separately. Soft-bodied rotifers were found to degrade and become indistinguishable in the anterior part of the alimentary tract, while cladocerans and copepods could still be identified in the posterior part. Assessing the diet of a larva on the basis of its whole alimentary tract contents was found to give biased results. More reliable estimates of the proportions of zooplankton taxa in the diet could be achieved from the first quarter of the alimentary tract.     

Experimental study of a new biological preparation for treating E. coli infection and Proteus dysbacteriosis in young infants

The action of a new biological preparation intended for the treatment of E. coli infection and Proteus dysbacteriosis in children has been studied in experiments on mice and suckling rabbits. The protective activity of anti-E. coli and anti-Proteus lactoglobulin has been found to exceed that of normal lactoglobulin 6- to 13-fold. When subjected to the action of proteolytic enzymes of the gastrointestinal tract, the preparation retains its preventive properties on the level of the native preparation, which confirms the possibility of the oral administration of the preparation in clinical practice without protecting it from the proteolytic action of the enzymes of the gastrointestinal tract.     

Beyond diversity: functional microbiomics of the human colon

Molecular tools have revealed wide microbial diversity in the human alimentary tract. Most intestinal microorganisms have not been cultured and the in situ functions of distinct groups of the intestinal microbiota are largely unknown but pivotal to understanding the role of these microorganisms in health and disease. Promising strategies to gain more insight into the functionality of the complex microbial communities in the human alimentary tract, including fermentation processes in the colon, are discussed. These research approaches could provide a basis for the definition of a healthy gut based on key properties of microbial functionality. This will also enable the development of direct nutritional strategies for intestinal disease prevention and health promotion.     

The Generalized Shwartzman Reaction in Association With E. Coli Enterotoxemia in a Pig

A pig at the age of approx. 10 weeks died after four days of illness. Distinct necrotic changes were found both in the skin and the cortex of the kidneys. The histological examination revealed fibrinoid thrombi in skin vessels. In the kidneys similar thrombi were observed in capillaries of the glomeruli and in their afferent arterioles and in the interlobular arteries. In these vessels there were also a fibrinoid mural necrosis. These changes were in accordance with those expected to occur in the generalized Shwartzman reaction (GSR). The diagnosis of Escherichia coli enterotoxemia was based on the pathomorphological changes in the alimentary tract. The E. coli enterotoxemia was considered the cause of the GSR-changes.     

On the optimal growth of the alimentary tract in avian postembryonic development

It was shown in the mathematical model described elsewhere that when growth rate of the chicks is maximized and not constrained by the food availability, the optimal relationship between body mass and alimentary tract mass should conform to a single straight line, or two-, or three-segmented straight lines. Here, we present the data on growth of 11 bird species, and we test the model using the mass of intestines as an indicator of growth of the alimentary tract. The results support the predictions of the model for altricial species and contradict them for precocials. Since precocial species examined here were not food-limited, we suggest that the lack of optimal growth of their alimentary tract is inherent to their mode of development. This may account for their lower growth rate, as compared to altricials. The existence of the optimal growth of the alimentary tract in altricial nestlings suggests that under natural conditions the food is much more abundant than it is generally assumed.     

The anatomy and histology of the alimentary tract of the carnivorous fish the pike Esox lucius L.

The alimentary tract of the pike is described, relating its feeding habits to its intestinal gut histology. It is a carnivorous species having a short oesophagus, pouch-like stomach and a short intestine with two convolutions. Stratified epithelium with columnar cells and many goblet cells are present in the oesophagus, columnar epithelial cells only in the stomach, and both cell types in the intestine.
Eosinophils in the mucosa of the oesophagus originate from connective tissue cells and lymphocytes and neutrophils are present. The lamina propria is composed of a stratum granulosum, stratum compactum, blood vessels and loose areolar tissue. The stratum compactum is a strengthening substance, composed of collagen, characteristic of carnivorous teleosts. The circular and longitudinal muscle layers and serosa are similar to those of other carnivorous teleosts.
The pancreas and liver are briefly described, the pancreas being the unusual compact type not often found in teleosts. The B cells are seen in the periphery and a cells in the centre of the islets. The liver is a unilobular organ, having oil storage as a major function.
The distribution of goblet cell mucin is given, differentiating it into neutral and acid mucosubstances. Nine levels of alimentary tract were examined in the mucin distribution study. The functions of mucin in the pike are digestion, absorption, protection and lubrication.     

Virulence or Niche Factors: What's in a Name?

The increasing interest in the human microbiota raises some interesting questions about the terminology we use to describe some of the structures and strategies employed by commensal and pathogenic microbes to compete in these complex biological ecosystems. For example, all microbes arriving in the alimentary tract face the task of surviving passage through the stomach, coping with bile, interacting with the immune system, competing with the established microbiota, and obtaining sufficient nutrients to gain a foothold in this hostile environment. It is not surprising then that many gastrointestinal microbes (both pathogens and commensals) use similar strategies to overcome the challenges associated with this particular biological niche. Given that many of these structures and strategies were discovered and characterized in pathogens and because they often play important roles in establishing and maintaining an infection, they have often been characterized as virulence factors. It would be misleading to describe the same strategies and structures found in harmless commensals as “virulence factors,” since they represent a sine qua non for life in the gastrointestinal tract. It may be time to reconsider and refer to them as “niche factors,” both in terms of providing scientific accuracy but also in light of the growing interest in using gut microbes as probiotics, where the distinction between virulence factors and niche factors is likely to be very important from a regulatory perspective.     

儿童过敏性紫癜合并消化道出血的影响因素分析

目的:探讨过敏性紫癜合并消化道出血的相关危险因素。方法:回顾性分析2013年9月至2016年6月在武汉协和医院儿科住院治疗的80例过敏性紫癜初诊患儿的临床资料,根据是否合并消化道出血分为消化道出血组11例,非消化道出血组69例,比较两组患儿的年龄、地区、性别、发病季节、紫癜分布特征、是否合并紫癜性肾炎、hsCRP、ESR、血常规、生化等。结果:与非消化道出血组相比,消化道出血组患儿的发病季节、血清超敏C反应蛋白(hsCRP)、血清钙离子(Ca)水平差异均有统计学意义(P0.05),两组紫癜性肾炎发病率比较差异无统计学意义,但消化道出血组合并紫癜性肾炎的比例(45.5%)明显高于非消化道出血组(21.7%)。结论:夏冬季节、高水平血清CRP、低水平血清Ca~(2+)是过敏性紫癜患儿合并消化道出血的危险因素。     

Calcitonin-like immunochemical staining in the alimentary tract of Ciona intestinalis L.

Summary Calcitonin-like immunoreactivity has been found with the peroxidase-anti-peroxidase (PAP) method in cells of the epithelium of the alimentary tract as well as in nerve cells and nerve fibers in the connective tissue underlying the epithelium of the alimentary tract of Ciona intestinalis L. The nature of these cells is discussed with reference to endocrine-like cells found in the alimentary tract of other protochordates and to the possible dual role of calcitonin occurring in the gastroenteropancreatic system, on the one hand, and in the nervous system, on the other.