Histological characterization of the gastrointestinal tract of the adult horseshoe crab (Limulus polyphemus) with special reference to the stomach.

The American horseshoe crab (Limulus polyphemus) is one of four extant species in the Order Xiphosura, subphylum Chelicerata, and are evolutionarily more closely related to scorpions and spiders, than crabs. The basic structure, function, and physiology of these invertebrates and their internal organs are not well documented in the literature. In this study, the gastrointestinal system, with a focus on the stomach, of adult L. polyphemus were assessed by gross and histologic methods to further characterize the pyloric valve, the lining of the ventricular lumen, and the muscular tunics of the stomach. Determination of normal anatomical structure of this organ system, along with characterization of the esophagus and intestinal tract, will set a standard against which tissue abnormalities, such as those seen with disease or pathology were to arise, would allow for better interpretation.

Antigen retrieval and clearing for whole-organ immunofluorescence by FLASH.

Advances in light-sheet and confocal microscopy now allow imaging of cleared large biological tissue samples and enable the 3D appreciation of cell and protein localization in their native organ environment. However, the sample preparations for such imaging are often onerous, and their capability for antigen detection is limited. Here, we describe FLASH (fast light-microscopic analysis of antibody-stained whole organs), a simple, rapid, fully customizable technique for molecular phenotyping of intact tissue volumes. FLASH utilizes non-degradative epitope recovery and membrane solubilization to enable the detection of a multitude of membranous, cytoplasmic and nuclear antigens in whole mouse organs and embryos, human biopsies, organoids and Drosophila. Retrieval and immunolabeling of epithelial markers, an obstacle for previous clearing techniques, can be achieved with FLASH. Upon volumetric imaging, FLASH-processed samples preserve their architecture and integrity and can be paraffin-embedded for subsequent histopathological analysis. The technique can be performed by scientists trained in light microscopy and yields results in <1 week.

In Vivo Evaluation of the Chronic Oral Toxicity of the Marine Toxin Palytoxin.

Palytoxin (PLTX) is one of the most poisonous substances known to date and considered as an emergent toxin in Europe. Palytoxin binds to the Na+-K+ ATPase, converting the enzyme in a permeant cation channel. This toxin is known for causing human fatal intoxications associated with the consumption of contaminated fish and crustaceans such as crabs, groupers, mackerel, and parrotfish. Human intoxications by PLTX after consumption of contaminated fishery products are a serious health issue and can be fatal. Different reports have previously explored the acute oral toxicity of PLTX in mice. Although the presence of palytoxin in marine products is currently not regulated in Europe, the European Food Safety Authority expressed its opinion on PLTX and demanded assessment for chronic toxicity studies of this potent marine toxin. In this study, the chronic toxicity of palytoxin was evaluated after oral administration to mice by gavage during a 28-day period. After chronic exposure of mice to the toxin, a lethal dose 50 (LD50) of 0.44 µg/kg of PLTX and a No-Observed-Adverse-Effect Level (NOAEL) of 0.03 µg/kg for repeated daily oral administration of PLTX were determined. These results indicate a much higher chronic toxicity of PLTX and a lower NOAEL than that previously described in shorter treatment periods, pointing out the need to further reevaluate the levels of this compound in marine products.

Cryptobia iubilans Infections in Discus Fish in Trinidad and Tobago.

Discus (Symphysodon spp.) are costly and prized specimens in the international ornamental fish trade. The majority of discus submitted to the Aquatic Animal Health Unit at the University of the West Indies School of Veterinary Medicine for necropsy between September 2010 and September 2015 had lesions consistent with Cryptobia iubilans infection, thus prompting this study. To determine the prevalence of the flagellated gastrointestinal protozoan C. iubilans in discus fish, 32 discus were sourced from 10 suppliers, including breeders, importers, and hobbyists across Trinidad. Fish were euthanized, and the internal organs, particularly the stomach and intestine, were observed under a light microscope for characteristic granulomatous lesions and/or live C. iubilans parasites. All wet-mount slides on which granulomas were observed were also Ziehl-Neelsen acid-fast stained to presumptively exclude the presence of Mycobacterium spp., the main differential when diagnosing C. iubilans-associated granulomatous gastritis or to determine the presence of dual infections. Further histological analyses were performed on stomach and intestinal sections, and transmission electron microscopy was used to confirm the parasite in stomach sections. The prevalence of C. iubilans infection was found to be 81.3%, and the prevalence of presumptive dual infections with Mycobacterium spp. was found to be 21.9%. To the best of our knowledge, this is the first documented study of C. iubilans infections in the wider Caribbean region.

Biomechanical and microstructural characterisation of the porcine stomach wall: Location- and layer-dependent investigations.

The mechanical properties of the stomach wall help to explain its function of storing, mixing, and emptying in health and disease. However, much remains unknown about its mechanical properties, especially regarding regional heterogeneities and wall microstructure. Consequently, the present study aimed to assess regional differences in the mechanical properties and microstructure of the stomach wall. In general, the stomach wall and the different tissue layers exhibited a nonlinear stress-stretch relationship. Regional differences were found in the mechanical response and the microstructure. The highest stresses of the entire stomach wall in longitudinal direction were found in the corpus (201.5 kPa), where food is ground followed by the antrum (73.1 kPa) and the fundus (26.6 kPa). In contrast, the maximum stresses in circumferential direction were 39.7 kPa, 26.2 kPa, and 15.7 kPa for the antrum, fundus, and corpus, respectively. Independent of the fibre orientation and with respect to the biaxial loading direction, partially clear anisotropic responses were detected in the intact wall and the muscular layer. In contrast, the innermost mucosal layer featured isotropic mechanical characteristics. Pronounced layers of circumferential and longitudinal muscle fibres were found in the fundus only, whereas corpus and antrum contained almost exclusively circumferential orientated muscle fibres. This specific stomach structure mirrors functional differences in the fundus as well as corpus and antrum. Within this study, the load transfer mechanisms, connected with these wavy layers but also in total with the stomach wall's microstructure, are discussed. STATEMENT OF SIGNIFICANCE: This article examines for the first time the layer-specific mechanical and histological properties of the stomach wall attending to the location of the sample. Moreover, both mechanical behaviour and microstructure were explicitly match identifying the heterogeneous characteristics of the stomach. On the one hand, the results of this study contribute to the understanding of stomach mechanics and thus to their functional understanding of stomach motility. On the other hand, they are relevant to the fields of constitutive formulation of stomach tissue, whole stomach mechanics, and stomach-derived scaffolds i.e., tissue-engineering grafts.

In vitro-in vivo evaluation of chitosan-PLGA nanoparticles for potentiated gastric retention and anti-ulcer activity of diosmin.

BACKGROUND: Diosmin showed poor water solubility and low bioavailability. Poly(d,l-lactide-co-glycolide) (PLGA) nanoparticles were successfully used to improve the drugs solubility and bioavailability. Coating of PLGA nanoparticles with chitosan can ameliorate their gastric retention and cellular uptake. METHODOLOGY: PLGA nanoparticles of diosmin were prepared using different drug and polymer amounts. Nanoparticles were selected based on entrapment efficiency% (EE%) and particle size measurements to be coated with chitosan. The selected nanoparticles either uncoated or coated were evaluated regarding morphology, ζ-potential, solid-state characterization, in vitro release, storage stability, and mucoadhesion. The anti-ulcer activity (AA) against ethanol-induced ulcer in rats was assessed through macroscopical evaluation, histopathological examination, immunohistochemical localization of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and transmission electron microscopic examination of gastric tissues compared to free diosmin (100 mg/kg) and positive control. RESULTS: Based on EE% and particle size measurements, the selected nanoparticles, either uncoated or coated with 0.1% w/v chitosan, were based on 1:15 drug-PLGA weight ratio and 20 mg diosmin employing methylene chloride as an organic phase. Examination by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed nanoscopic spherical particles. Drug encapsulation within the selected nanoparticles was suggested by Fourier transform-infrared, differential scanning calorimetry (DSC) and X-ray diffractometry results. Chitosan-coated nanoparticles were more stable against size enlargement probably due to the higher ζ-potential. Only coated nanoparticles showed gastric retention as revealed by SEM examination of stomach and duodenum. The superior AA of coated nanoparticles was confirmed by significant reduction in average mucosal damage, the majority of histopathological changes and NF-κB expression in gastric tissue when compared to positive control, diosmin and uncoated nanoparticles as well as insignificant difference relative to normal control. Coated nanoparticles preserved the normal ultrastructure of the gastric mucosa as revealed by TEM examination. CONCLUSION: The optimized chitosan-coated PLGA nanoparticles can be represented as a potential oral drug delivery system of diosmin.

Características morfológicas do estômago de jaguatirica (Leopardus pardalis - Linnaeus, 1758) / Morphological characteristics of the stomach of the ocelot (Leopardus pardalis - Linnaeus, 1758)

Leopardus pardalis é uma das espécies de felinos neotropicais mais estudadas em seus aspectos ecológicos, porém informações de questões morfofisiológicas do trato digestório não são encontradas na literatura. Visando contribuir com tais informações, o objetivo deste artigo foi caracterizar a morfologia do estômago dessa espécie. Nesta pesquisa, foram utilizados cinco exemplares adultos, coletados após óbito por atropelamento ou doados pelo IBAMA ao Laboratório de Zoologia e Morfologia Animal da Universidade do Estado de Mato Grosso - Alta Floresta. Os animais foram fixados com solução aquosa de formaldeído a 10%, dissecados por meio de técnicas anatômicas. Além dos estudos anatômicos, também foram coletados tecidos para microscopia. As análises macroscópicas revelaram que o estômago era do tipo unicavitário, com presença de pequena e grande curvatura, localizado no antímero esquerdo e constituído pelas regiões características do órgão. Em seus aspectos microscópicos, mostrou-se formado pelas quatro túnicas usuais do tubo digestório: túnica mucosa, submucosa, muscular e serosa, cada uma com as particularidades características de cada região, principalmente na túnica mucosa. O estômago de L. pardalis revelou uma morfologia semelhante às espécies domésticas e selvagens, com particularidades histomorfológicas na região pilórica. Esse padrão pode estar relacionado a adaptações evolutivas no processo digestivo dessa espécie.(AU)

The species Leopardus pardalis is one of the species of neotropical felines more studied in its ecological aspects, however, information of morphophysiological questions of the digestive tract are not found in the literature. Aiming to contribute with such information, the objective of this work was to characterize the morphology of the stomach of this species. Five adult specimens, collected after death by trampling, or donated by IBAMA to the Laboratory of Zoology and Animal Morphology of the University of the State of Mato Grosso - Alta Floresta, were used in this research. The animals were fixed with aqueous solution of formaldehyde 10%, dissected through the basic techniques and instruments of anatomy, and later the material was collected for microscopy. The macroscopic analysis revealed that the stomach was of the unicavitary type, with small and great curvature, located in the left antimer and constituted by the characteristic regions of the organ. In its microscopic aspects it was formed by the four usual tunics of the digestive tube: tunica mucosa, submucosa, muscular and serosa, each one with the peculiarities characteristic of each region, mainly in the tunica mucosa. The stomach of L. pardalis revealed similar morphology to the domestic and wild species, with small histomorphological peculiarities in the pyloric region, which may be related to evolutionary adaptations in the digestive process of this species.(AU)

Acute Toxicity Assessment: Macroscopic and Ultrastructural Effects in Mice Treated with Oral Tetrodotoxin.

Tetrodotoxin (TTX) is an extremely toxic marine compound produced by different genera of bacteria that can reach humans through ingestion mainly of pufferfish but also of other contaminated fish species, marine gastropods or bivalves. TTX blocks voltage-gated sodium channels inhibiting neurotransmission, which in severe cases triggers cardiorespiratory failure. Although TTX has been responsible for many human intoxications limited toxicological data are available. The recent expansion of TTX from Asian to European waters and diversification of TTX-bearing organisms entail an emerging risk of food poisoning. This study is focused on the acute toxicity assessment of TTX administered to mice by oral gavage following macroscopic and microscopic studies. Necropsy revealed that TTX induced stomach swelling 2 h after administration, even though no ultrastructural alterations were further detected. However, transmission electron microscopy images showed an increase of lipid droplets in hepatocytes, swollen mitochondria in spleens, and alterations of rough endoplasmic reticulum in intestines as hallmarks of the cellular damage. These findings suggested that gastrointestinal effects should be considered when evaluating human TTX poisoning.

The gastric sieve of penaeid shrimp species is a sub-micrometer nutrient filter.

Unlike that of vertebrates, the penaeid shrimp stomach is of ectodermic origin and is thus covered by a cuticle that is sloughed upon molting. It is composed of two chambers, here called the anterior and posterior stomach chambers, ASC and PSC, respectively. The PSC contains a filtration structure variously called a pyloric filter, filter press, gastric filter or gastric sieve (GS), and the last of these will be used here. The GS resembles an elongated, inverted-V, dome-like, chitinous structure with a midline ridge that is integral to the ventral base of the PSC. The dome surface is covered with a carpet-like layer of minute, comb-like setae bearing laterally branching setulae. This carpet serves as a selective filter that excludes large partially digested food particles but allows smaller particles and soluble materials to enter hepatopancreatic ducts that conduct them into the shrimp hepatopancreas (HP), where further digestion and absorption of nutrients takes place. Although the GS function is well known, its exclusion limit for particulate material has not been clearly defined. Using histological and ultra-structure analysis, we show that the GS sieve pore diameter is approximately 0.2-0.7 µm in size, indicating a size exclusion limit of substantially less than 1 µm. Using fluorescent microbeads, we show that particles of 1 µm diameter could not pass through the GS but that particles of 0.1 µm diameter did pass through to accumulate in longitudinal grooves and move on to the HP, where some were internalized by tubule epithelial cells. We found no significant difference in these sizes between the species Penaeus monodon and Penaeus vannamei or between juveniles and adults in P. vannamei This information will be of value for the design of particulate feed ingredients such as nutrients, therapeutic drugs and toxin-absorbing materials that may selectively target the stomach, intestine or HP of cultivated shrimp.

Structure of the alimentary tract in the Atlantic mudskipper Periophthalmus barbarus (Gobiidae: Oxudercinae): anatomical, histological and ultrastructural studies.

The alimentary tract of oxudercine gobies is characterized by a lack of an anatomically distinct stomach, owing to which they are classified as stomachless. Since the environment, food requirements, and feeding habits have a significant impact on the anatomy of the alimentary tract of fish, it was assumed that predominantly carnivorous, semi-terrestrial mudskippers would have a stomach. In order to verify this hypothesis, anatomical, histological, histochemical and ultrastructural analysis of the alimentary tract of the Atlantic mudskipper Periophthalmus barbarus was performed. The results revealed that despite a lack of clear anatomical distinction within the alimentary tract, there were four well-distinguished sections visible at the histological level: oesophagus, stomach, intestine, and rectum. The division was enhanced by the presence of a pyloric sphincter and an ileorectal valve. The stomach contained tubular glands composed of oxynticopeptic cells. Gland cells had pepsinogen granules and a well-developed tubulovesicular network of smooth membranes, which indicates the secretion of gastric juice. The presence of neutral mucus in the apical region of surface epithelial cells as protection against hydrochloric acid as well as the presence of active pepsin also confirm gastric function. However, low pepsin activity seems to implies low protein digestion. The results of this study indicate that the Atlantic mudskipper P. barbarus has a functional stomach.

Natural history of Helicobacter pylori VacA toxin in human gastric epithelium in vivo: vacuoles and beyond.

Uptake, intracellular trafficking and pathologic effects of VacA toxin from Helicobacter pylori have been widely investigated in vitro. However, no systematic analysis investigated VacA intracellular distribution and fate in H. pylori-infected human gastric epithelium in vivo, using ultrastructural immunocytochemistry that combines precise toxin localization with analysis of the overall cell ultrastructure and intercompartimental/interorganellar relationships. By immunogold procedure, in this study we investigated gastric biopsies taken from dyspeptic patients to characterize the overall toxin's journey inside human gastric epithelial cells in vivo. Endocytic pits were found to take up VacA at sites of bacterial adhesion, leading to a population of peripheral endosomes, which in deeper (juxtanuclear) cytoplasm enlarged and fused each other to form large VacA-containing vacuoles (VCVs). These directly opened into endoplasmic reticulum (ER) cisternae, which in turn enveloped mitochondria and contacted the Golgi apparatus. In all such organelles we found toxin molecules, often coupled with structural damage. These findings suggest direct toxin transfer from VCVs to other target organelles such as ER/Golgi and mitochondria. VacA-induced cytotoxic changes were associated with the appearance of auto(phago)lysosomes containing VacA, polyubiquitinated proteins, p62/SQSTM1 protein, cathepsin D, damaged mitochondria and bacterial remnants, thus leading to persistent cell accumulation of degradative products.

Residual gastric volume evaluation with ultrasonography after ingestion of carbohydrate- or carbohydrate plus glutamine-enriched beverages: a randomized, crossover clinical trial with healthy volunteers / Avaliação do volume residual gástrico em voluntários saudáveis usando a ultrassonografia, após ingestão de solução líquida enriquecida com carboidrato e glutamina. Estudo clínico, randomizado, duplo cego e cruzado

ABSTRACT BACKGROUND Abbreviation of preoperative fasting to 2 hours with maltodextrin (CHO)-enriched beverage is a safe procedure and may enhance postoperative recovery. Addition of glutamine (GLN) to CHO beverages may include potential benefits to the metabolism. However, by adding a nitrogenous source to CHO beverages, gastric emptying may be delayed and increase the risk of bronchoaspiration during anesthesia. OBJECTIVE In this study of safety, we aimed at investigating the residual gastric volume (RGV) 2 hours after the intake of either CHO beverage alone or CHO beverage combined with GLN. METHODS We performed a randomized, crossover clinical trial. We assessed RGV by means of abdominal ultrasonography (US) in 20 healthy volunteers (10 males and 10 females) after an overnight fast of 8 hours. Then, they were randomized to receive 600 mL (400 mL immediately after US followed by another 200 mL 2 hours afterwards) of either CHO (12.5% maltodextrin) or CHO-GLN (12.5% maltodextrin plus 15 g GLN). Two sequential US evaluations were done at 120 and 180 minutes after ingestion of the second dose. The interval of time between ingestion of the two types of beverages was 2 weeks. RESULTS The mean (SD) RGV observed after 8 hours fasting (13.56±13.25 mL) did not statistically differ (P>0.05) from the RGV observed after ingesting CHO beverage at both 120 (16.32±11.78 mL) and 180 minutes (14.60±10.39 mL). The RGV obtained at 120 (15.63±18.83 mL) and 180 (13.65±10.27 mL) minutes after CHO-GLN beverage also was not significantly different from the fasting condition. CONCLUSION The RGV at 120 and 180 minutes after ingestion of CHO beverage combined with GLN is similar to that observed after an overnight fast.

RESUMO CONTEXTO A abreviação do jejum pré-operatório com solução enriquecida com maltodextrina é segura, recomendada por sociedades de anestesiologia e acelera a recuperação pós-operatória. A associação de glutamina à maltodextrina resultaria em benefícios metabólicos, porém, esta associação pode alterar o volume do resíduo gástrico e consequentemente risco de broncoaspiração. OBJETIVO Avaliaremos, usando a ultrassonografia, o volume residual gástrico em jejum de 8 horas e após 120 e 180 minutos da ingestão de solução de maltodextrina isolada ou associada a 15 g de glutamina. MÉTODOS Estudo clínico, randomizado, duplo cego e cruzado. Vinte voluntários saudáveis, sendo 10 do sexo masculino e 10 do sexo feminino, foram submetidos a seguinte sequência de avaliação, independente da solução usada. Os voluntários foram avaliados em jejum de 8 horas, 120 e 180 minutos após a ingestão da solução de maltodextrina 12,5% e 120 e 180 após a ingestão da solução de maltodextrina 12,5% mais 15 g de glutamina. RESULTADOS Não houve diferença estatisticamente significativa entre os volumes obtidos após jejum de 8 horas (13,56 mL) e os obtidos após 120 (16,32 mL) e 180 minutos (14,60 mL) da ingestão da solução de maltodextrina 12,5% (P>0,05). Para a solução enriquecida com glutamina, os volumes obtidos após 120 minutos (15,63 mL) e 180 minutos (13,65 mL) também não demostraram diferença estatisticamente significativa quando comparados ao jejum (P>0,05). CONCLUSÃO O volume residual gástrico após 120 e 180 minutos da ingestão das soluções de maltodextrina a 12,5% isolada ou associada a 15 g de glutamina é semelhante ao observado em jejum.

Morphological and scanning electron microscopy studies of the stomach of the Egyptian fruit bat (Rousettus aegyptiacus) / Estudios morfológico y de microscopía electrónica de barrido del estómago del murciélago egipcio de la fruta (Rousettus aegyptiacus)

This study was performed to investigate the histomorphological characters of the Egyptian fruit bat stomach using the light and scanning electron microscope. The stomachs of fourteen adult normal healthy Egyptian fruit bats of both sexes were used. Stomach was tubular with an elongated fundic part and a long narrow pyloric part. Internally, the superficial epithelium was disposed in filiform form, the longitudinal rugaes extended throughout the length of the stomach, their numbers were high but they were thin and branched in the fundic region, while in the cardiac and pyloric region reached to 3 or 4 thick longitudinal and not branched rugaes. Under the scanning electron microscopy, we found differences in the appearance of middle part with the peripherical part of the fundic region, like the appearance of honeycomb buildings in the middle part different to round elevated formations at the periphery of fundic region. At high magnification of cardiac region, there was an aggregation of epithelial cells without regular shape, while there were elevated mountains areas in the pyloric region. We concluded that the stomachs of Egyptian fruit bat had special characters different to other mammals.

En este trabajo se estudiaron las características histomorfológicas del estómago del murciélago egipcio de la fruta, a través de microscopía electrónica de barrido. Para el estudio se utilizaron 14 estómagos de murciélagos egipcios de la fruta, adultos sanos y de ambos sexos. El estómago era tubular con una región fúndica alargada y una región pilórica larga y estrecha. Internamente, el epitelio era filiforme y las rugas longitudinales se extendían a lo largo del estómago, su número era alto, delgado y ramificado en la región fúndica, mientras que en las regiones del cardias y pilórica alcanzaban un número de 3 o 4, gruesos, longitudinales y no ramificados. Al microscopio electrónico de barrido se encontraron diferencias en la apariencia de la parte media respecto a la parte periférica de la región fúndica, al igual que la aparición de estructuras en nido de abeja en la parte media, diferente a las formaciones redondas elevadas observadas en la periferia de la región fúndica. A mayor ampliación de la región del cardias, se observó una agregación de células epiteliales sin forma regular, mientras que en la región pilórica, se encontraron áreas elevadas. Concluimos que los estómagos del murciélago egipcio de la fruta presentan caracteres especiales diferentes a la de otros mamíferos.

Residual gastric volume evaluation with ultrasonography after ingestion of carbohydrate- or carbohydrate plus glutamine-enriched beverages: a randomized, crossover clinical trial with healthy volunteers.

BACKGROUND: - Abbreviation of preoperative fasting to 2 hours with maltodextrin (CHO)-enriched beverage is a safe procedure and may enhance postoperative recovery. Addition of glutamine (GLN) to CHO beverages may include potential benefits to the metabolism. However, by adding a nitrogenous source to CHO beverages, gastric emptying may be delayed and increase the risk of bronchoaspiration during anesthesia. OBJECTIVE: - In this study of safety, we aimed at investigating the residual gastric volume (RGV) 2 hours after the intake of either CHO beverage alone or CHO beverage combined with GLN. METHODS: - We performed a randomized, crossover clinical trial. We assessed RGV by means of abdominal ultrasonography (US) in 20 healthy volunteers (10 males and 10 females) after an overnight fast of 8 hours. Then, they were randomized to receive 600 mL (400 mL immediately after US followed by another 200 mL 2 hours afterwards) of either CHO (12.5% maltodextrin) or CHO-GLN (12.5% maltodextrin plus 15 g GLN). Two sequential US evaluations were done at 120 and 180 minutes after ingestion of the second dose. The interval of time between ingestion of the two types of beverages was 2 weeks. RESULTS: - The mean (SD) RGV observed after 8 hours fasting (13.56±13.25 mL) did not statistically differ (P>0.05) from the RGV observed after ingesting CHO beverage at both 120 (16.32±11.78 mL) and 180 minutes (14.60±10.39 mL). The RGV obtained at 120 (15.63±18.83 mL) and 180 (13.65±10.27 mL) minutes after CHO-GLN beverage also was not significantly different from the fasting condition. CONCLUSION: - The RGV at 120 and 180 minutes after ingestion of CHO beverage combined with GLN is similar to that observed after an overnight fast.

Unique Cellular Lineage Composition of the First Gland of the Mouse Gastric Corpus.

The glandular stomach has two major zones: the acid secreting corpus and the gastrin cell-containing antrum. Nevertheless, a single gland lies at the transition between the forestomach and corpus in the mouse stomach. We have sought to define the lineages that make up this gland unit at the squamocolumnar junction. The first gland in mice showed a notable absence of characteristic corpus lineages, including parietal cells and chief cells. In contrast, the gland showed strong staining of Griffonia simplicifolia-II (GSII)-lectin-positive mucous cells at the bases of glands, which were also positive for CD44 variant 9 and Clusterin. Prominent numbers of doublecortin-like kinase 1 (DCLK1) positive tuft cells were present in the first gland. The first gland contained Lgr5-expressing putative progenitor cells, and a large proportion of the cells were positive for Sox2. The cells of the first gland stained strongly for MUC4 and EpCAM, but both were absent in the normal corpus mucosa. The present studies indicate that the first gland in the corpus represents a unique anatomic entity. The presence of a concentration of progenitor cells and sensory tuft cells in this gland suggests that it may represent a source of reserve reparative cells for adapting to severe mucosal damage.

The Third Dimension of Telocytes Revealed by FIB-SEM Tomography.

Lately, spatial three-dimensional (3D) identity of cells and their interrelations with the environment that surrounds it represent a challenging trend with the purpose to achieve a holistic view over the functions. Combining data from different imaging of cells in the third dimension can offer insight into behavior modalities making a world of difference. This chapter outlines a breakthrough in telocyte research by volume electron microscopy with the aid of focused ion beam scanning electron microscopy (FIB-SEM). Reconstructing 3D (three-dimensional) appearance of telocytes from a set of two-dimensional (2D) images by FIB-SEM tomography allowed to extract valuable data about their volume in nanoscale dimensions such as the three-dimensional morphology of telopodes and extracellular vesicles.

Ultrastructural and immunohistochemical effects of aqueous leave extract of Xylopia aethiopica on the stomach in streptozotocin-induced diabetic rats / Efectos ultraestructurales e inmunohistoquímicos del extracto acuoso de la hoja Xylopia aethiopica en el estómago de ratas diabéticas inducidas por estreptozotocina

Gastrointestinal pathology in diabetic patients has become a source of concern in recent times. The aim of this study was to investigate the ultrastructural and immunohistochemical effects of aqueous leaf extract of Xylopia aethiopica on the stomach in streptozotocin-induced diabetic rats. This study was conducted using thirty adult Wistar rats. The animals were divided into three groups (n= 10). Group A was the control animals (administered with equivalent volume of citrate buffer), group B was diabetic animals induced by a single intraperitoneal injection of streptozotocin dissolved in citrate buffer (65 mg/kg) and group C was diabetic animals treated with 200 mg/kg body weight of aqueous leave extract of X. aethiopica for twenty five days. At the expiration of the study, all the animals in each of the groups were sacrificed and the stomach excised and fixed in both 10 % formol and karnovsky fixatives immunohistochemical, light microscopic and electron microscopic studies respectively. The results showed a gradual decline (P<0.05) in the blood glucose level in the extract treated group as against the increment in untreated diabetic group. There was a distortion of the glandular mucosa and epithelium in the untreated diabetic group vis-à-vis the extract treated and control groups. The immunohistochemical staining and percentage immunoreactivity of the stomach of untreated diabetic group showed that the immunoexpression of H+/K+-ATPase were sparse and significantly (p<0.000) lower compared with the control group. There was a better staining pattern for H+/K+-ATPase gastric proton pump in the group treated with aqueous leaf extract of X. aethiopica as compared with the untreated diabetic group. The ultrastructural studies of untreated diabetic group revealed a reduction in the density of mitochondria as compared with the control group. Treatment with leaf extract of X. aethiopica increased the mitochondrial density as well as uniform dispersal of chromatin. It is concluded that diabetes causes gastric pathology thus resulting in morphological changes in the gastric histo-architecture and parietal cells. The aqueous leaf extract of X. aethiopica enhances the recovery/restoration of these defects in streptozotocin induced diabetic rats and as such, may play a significant role in the management of complications associated with diabetes mellitus.

La enfermedad gastrointestinal en pacientes diabéticos se ha convertido en una fuente de preocupación en los últimos tiempos. El objetivo fue investigar los efectos ultraestructurales e inmunohistoquímicos de extracto acuoso de la hoja de Xylopia aethiopica en el estómago de ratas con diabetes inducida por estreptozotocina. Se utilizaron 30 ratas Wistar adultas, divididas en tres grupos (n= 10). El Grupo A, control (se le administró un volumen equivalente de tampón de citrato); el Grupo B, animales diabéticos inducidos por una sola inyección intraperitoneal de estreptozotocina disuelta en tampón de citrato (65 mg/kg) y el Grupo C, animales diabéticos con 200 mg/kg peso corporal tratados con extracto acuoso de X. aethiopica durante 25 d. Luego, todos los animales fueron sacrificados, se les extirpó el estómago y fijó en formol al 10 % y en fijador Karnovsky para anticuerpos monoclonales contra la bomba de protones gátrica H+/K+-ATPasa; las muestras se observaron mediante microscopías óptica y electrónica. Los resultados mostraron una disminución gradual (P<0,05) en el nivel de glucosa en sangre del grupo tratado con el extracto, contra un incremento en el grupo diabético no tratado. Hubo una distorsión de la mucosa glandular y el epitelio en el grupo diabético no tratado vis-à-vis los grupos tratados con extracto y el de control. La tinción inmunohistoquímica del estómago del grupo diabético no tratado, mostró escasas células parietales inmunorreactivas en el grupo diabético no tratado comparado con el grupo control. Hubo un mejor patrón de tinción en la bomba de protones gátrica H+/K+-ATPasa en el grupo tratado con el extracto de hoja acuosa de X. aethiopica, en comparación con el grupo diabético no tratado. Los estudios ultraestructurales del grupo diabético no tratado revelaron una reducción en la densidad de las mitocondrias en comparación con el grupo control. El tratamiento con extracto de hoja de X. aethiopica aumentó la densidad mitocondrial, así como la dispersión uniforme de la cromatina. Se concluye que la diabetes causa una enfermedad gástrica que genera cambios morfológicos en la histoarquitectura de las células parietales gástricas. El extracto de hoja acuosa de X. aethiopica mejora la recuperación/restauración de estos defectos en ratas diabéticas inducidas por estreptozotocina y, como tal, puede jugar un rol significativo en el tratamiento de las complicaciones asociadas con la diabetes mellitus.

Calcium Deposits in the Crayfish, Cherax quadricarinatus: Microstructure Versus Elemental Distribution.

The crayfish Cherax quadricarinatus stores calcium ions, easily mobilizable after molting, for calcifying parts of the new exoskeleton. They are chiefly stored as amorphous calcium carbonate (ACC) during each premolt in a pair of gastroliths synthesized in the stomach wall. How calcium carbonate is stabilized in the amorphous state in such a biocomposite remains speculative. The knowledge of the microstructure at the nanometer level obtained by field emission scanning electron microscopy and atomic force microscopy combined with scanning electron microscopy energy-dispersive X-ray spectroscopy, micro-Raman and X-ray absorption near edge structure spectroscopy gave relevant information on the elaboration of such an ACC-stabilized biomineral. We observed nanogranules distributed along chitin-protein fibers and the aggregation of granules in thin layers. AFM confirmed the nanolevel structure, showing granules probably surrounded by an organic layer and also revealing a second level of aggregation as described for other crystalline biominerals. Raman analyses showed the presence of ACC, amorphous calcium phosphate, and calcite. Elemental analyses confirmed the presence of elements like Fe, Na, Mg, P, and S. P and S are heterogeneously distributed. P is present in both the mineral and organic phases of gastroliths. S seems present as sulfate (probably as sulfated sugars), sulfonate, sulfite, and sulfoxide groups and, in a lesser extent, as sulfur-containing amino acids.

Histogenesis of the stomach of the pre-hatching quail: a light microscopic study.

The current study conducted a careful description of the histological events during the embryonic development of quail stomach. Daily histological specimens from the quail stomach from day 4 to day 17 post incubation were examined by light microscopy. The primitive gut tube of the embryonic quail appeared at day 4 post incubation. The gut tube consisted of an endodermal epithelium of pseudostratified type, surrounded by splanchnic mesenchyme. The prospective glandular epithelium invaginated at day 5 in the proventriculus and gradually developed to prospective proventricular glands. The muscular coat became distinguished at day 7 and day 8 in the proventriculus and gizzard, respectively. Transformation into simple columnar epithelium occurred in both proventriculus and the gizzard at day 12. The gizzard epithelium gave rise to tubular invaginations also at day 12. Canalization of the gizzard tubular glands was recognized at day 14. By day 15, the proventricular surface epithelium invaginated in a concentric manner around a central cavity to form immature secretory units that contained inactive oxyntico-peptic cells. The mucosal folding in the gizzard appeared at day 15 to form plicae and sulci. The wall of the proventriculus and gizzard at day 17 acquired histological features of post-hatching birds.