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International Journal of Biological... Nov 2017Fish are reported to exhibit chitinase activity in the stomach. Analyses of fish stomach chitinases have shown that these enzymes have the physiological function of... (Review)
Review
Fish are reported to exhibit chitinase activity in the stomach. Analyses of fish stomach chitinases have shown that these enzymes have the physiological function of degrading chitinous substances ingested as diets. Osteichthyes, a group that includes most of the fishes, have several chitinases in their stomachs. From a phylogenetic analysis of the chitinases of vertebrates, these particular molecules were classified into a fish-specific group and have different substrate specificities, suggesting that they can degrade ingested chitinous substances efficiently. On the other hand, it has been suggested that coelacanth (Sarcopterygii) and shark (Chondrichthyes) have a single chitinase enzyme in their stomachs, which shows multiple functions. This review focuses on recent research on the biochemistry of fish stomach chitinases.
Topics: Animals; Chitinases; Fishes; Humans; Protein Transport; Stomach
PubMed: 28365290
DOI: 10.1016/j.ijbiomac.2017.03.118 -
JCI Insight Feb 2023Helicobacter pylori colonization of the gastric niche can persist for years in asymptomatic individuals. To deeply characterize the host-microbiota environment in H....
Helicobacter pylori colonization of the gastric niche can persist for years in asymptomatic individuals. To deeply characterize the host-microbiota environment in H. pylori-infected (HPI) stomachs, we collected human gastric tissues and performed metagenomic sequencing, single-cell RNA-Seq (scRNA-Seq), flow cytometry, and fluorescent microscopy. HPI asymptomatic individuals had dramatic changes in the composition of gastric microbiome and immune cells compared with noninfected individuals. Metagenomic analysis uncovered pathway alterations related to metabolism and immune response. scRNA-Seq and flow cytometry data revealed that, in contrast to murine stomachs, ILC2s are virtually absent in the human gastric mucosa, whereas ILC3s are the dominant population. Specifically, proportion of NKp44+ ILC3s out of total ILCs were highly increased in the gastric mucosa of asymptomatic HPI individuals, and correlated with the abundance of selected microbial taxa. In addition, CD11c+ myeloid cells and activated CD4+ T cells and B cells were expanded in HPI individuals. B cells of HPI individuals acquired an activated phenotype and progressed into a highly proliferating germinal-center stage and plasmablast maturation, which correlated with the presence of tertiary lymphoid structures within the gastric lamina propria. Our study provides a comprehensive atlas of the gastric mucosa-associated microbiome and immune cell landscape when comparing asymptomatic HPI and uninfected individuals.
Topics: Humans; Animals; Mice; Helicobacter pylori; Immunity, Innate; Single-Cell Gene Expression Analysis; Stomach; Gastric Mucosa; Plasma Cells; Helicobacter Infections
PubMed: 36810249
DOI: 10.1172/jci.insight.161042 -
The Surgical Clinics of North America Oct 2011The primary function of the stomach is to prepare food for digestion and absorption by the intestine. Acid production is the unique and central component of the... (Review)
Review
The primary function of the stomach is to prepare food for digestion and absorption by the intestine. Acid production is the unique and central component of the stomach's contribution to the digestive process. Acid bathes the food bolus while stored in the stomach, facilitating digestion. An intact defense against mucosal damage by the stomach's acid is essential to avoid ulceration. This article focuses on the physiology of gastric acid production, the stomach's defense mechanisms against acid injury, and the most common challenges to the gastric defenses. A brief description of the stomach's nonacid digestive capabilities is included.
Topics: Animals; Digestive System Physiological Phenomena; Gastric Acid; Gastric Mucosa; Humans; Stomach
PubMed: 21889024
DOI: 10.1016/j.suc.2011.06.010 -
Journal of Anatomy Oct 2021Because the stomach in situ has few distinctive surface features and changes shape dramatically with food intake, we have used micro-CT imaging combined with two...
Because the stomach in situ has few distinctive surface features and changes shape dramatically with food intake, we have used micro-CT imaging combined with two distinct contrast agents to (1) characterize the pattern of arteries, potential landmarks, on the stomach wall and (2) evaluate how meal-related shape changes affect the size of the different regions. Images generated with a contrast agent injected directly into the heart during perfusion enabled a thorough look at the organizational features of the stomach angioarchitecture. The stomach receives its blood supply primarily from two pairs of vessels, the gastric and gastroepiploic arteries. Each of the three regions of the stomach is delineated by a distinctive combination of arterial fields: the corpus, consistent with its dynamic secretory activity and extensive mucosa, is supplied by extensive arterial trees formed by the left and right gastric arteries, travelling, respectively, on the ventral and dorsal stomach surfaces. These major arteries course circularly from the lesser towards the greater curvature, distally along both left (or ventral) and right (or dorsal) walls of the corpus, and branch rostrally to supply the region. The muscular antrum is characterized by smaller arterial branches arising primarily from the right gastroepiploic artery that follows the distal greater curvature and secondarily from small, distally directed arteries supplied by the large vessels of the left and right gastric arteries. The forestomach, essentially devoid of mucosal tissue and separated from the corpus by the limiting ridge, is vascularized predominantly by a network of small arteries issued from the left gastroepiploic artery coursing around the proximal greater curvature, as well as from higher order and smaller branches issued by the gastric and celiac arteries. These distinctive arterial fields appear to distinguish the major gastric regions, irrespective of the degree of fill of the stomach. Volume assessments of stomach compartments were made from images of iodine-stained stomachs. By varying the delay time between eating and perfusion, we were able to probe the emptying behavior of the stomach and demonstrate that the regions of the stomach empty at different rates, thus changing the relative dimensions of the organ regions. Notably, and despite these shape changes, the gastric arteries appear to form a regular, particularly recognizable, and lateralized pattern corresponding to the corpus that should be of use in guiding surgical and experimental interventions.
Topics: Animals; Arteries; Gastric Artery; Rats; Stomach
PubMed: 34142374
DOI: 10.1111/joa.13480 -
FEMS Microbiology Reviews Sep 2013The human stomach is a formidable barrier to orally ingested microorganisms and was long thought to be sterile. The discovery of Helicobacter pylori, a carcinogenic... (Review)
Review
The human stomach is a formidable barrier to orally ingested microorganisms and was long thought to be sterile. The discovery of Helicobacter pylori, a carcinogenic bacterial pathogen that infects the stomach mucosa of more than one half of all humans globally, has started a major paradigm shift in our understanding of the stomach as an ecological niche for bacteria. The special adaptations that enable H. pylori to colonize this well-protected habitat have been intensively studied over the last three decades. In contrast, our knowledge concerning bacteria other than H. pylori in the human stomach is still quite limited. However, a substantial body of evidence documents convincingly that bacteria can regularly be sampled from the stomachs of healthy adults. Commonly detected phyla include Firmicutes, Actinobacteria, Bacteroidetes, and Proteobacteria, and characteristic genera are Lactobacillus, Streptococcus, and Propionibacterium. In this review, we summarize the available literature about the gastric microbiota in humans and selected model animals, discuss the methods used in its characterization, and identify gaps in our knowledge that need to be addressed to advance our understanding of the bacterial colonization of the different layers of the gastric mucosa and its potential role in health and disease.
Topics: Animals; Computational Biology; Helicobacter pylori; Humans; Microbiota; Stomach
PubMed: 23790154
DOI: 10.1111/1574-6976.12027 -
Anticancer Research Jan 2023In the modern minimally invasive era, diagnostic and therapeutic endoscopic interventions are one of the most emerging fields. For the new operational techniques, it is...
BACKGROUND/AIM
In the modern minimally invasive era, diagnostic and therapeutic endoscopic interventions are one of the most emerging fields. For the new operational techniques, it is a major aim to develop reliable instruments, such as suturing devices for flexible endoscopes. The aim of this study was to assess the feasibility of a safe and reproducible suturing technique with an endoluminal suturing device.
MATERIALS AND METHODS
The evaluation of the technique was performed in twenty explanted special prepared porcine stomachs. Three different techniques were compared, single stitches, figure-of-eight, or Z-pattern and running sutures in terms of suturing time and bursting pressure. After verification of the reliability of the method, a 3 cm long full thickness incision on the stomach was closed with the endoscopic suturing device in four surviving animals.
RESULTS
In our ex vivo studies, we have shown that the figure of 8 or Z- technique is the most optimal for stomach closure without considerable time-cost, thus this technique was chosen as the standard method for the in vivo study. The endoscopic stomach wall suturing was successful in all four cases, the postoperative period was uneventful and ended on the tenth postoperative day with autopsy.
CONCLUSION
With the applied suturing device, the endoscopic suturing of the stomach is safe and reproducible, thus a human application may also be justified.
Topics: Animals; Swine; Humans; Gastroscopy; Reproducibility of Results; Stomach; Suture Techniques; Sutures; Models, Theoretical
PubMed: 36585160
DOI: 10.21873/anticanres.16134 -
Journal of Morphology Sep 2022Muroid rodents mostly have a complex stomach: one part is lined with a cornified (nonglandular) epithelium, referred to as a "forestomach", whereas the rest is lined...
Muroid rodents mostly have a complex stomach: one part is lined with a cornified (nonglandular) epithelium, referred to as a "forestomach", whereas the rest is lined with glandular epithelium. Numerous functions for the forestomach have been proposed. We collated a catalog of anatomical depictions of the stomach of 174 muroid species from which the respective nonglandular and glandular areas could be digitally measured, yielding a "stomach ratio" (nonglandular:glandular area) as a scale-independent variable. Stomach ratios ranged from 0.13 to 20.15, and the coefficient of intraspecific variation if more than one picture was available for a species averaged at 29.7% (±21.5). We tested relationships of the ratio with body mass and various anatomical and ecological variables, including diet. There was a consistent phylogenetic signal, suggesting that closely related species share a similar anatomy. Apart from classifying stomachs into hemiglandular and discoglandular, no anatomical or ecological measure showed a consistent relationship to the stomach ratio. In particular, irrespective of statistical method or the source of dietary information, dietary proxies did not significantly correlate with the stomach ratio, except for a trend towards significance for invertivory (insectivory). Yet, even this relationship was not convincing: whereas highly insectivorous species had high but no low stomach ratios, herbivorous species had both low and high stomach ratios. Thus, the statistical effect is not due to a systematic increase in the relative forestomach size with invertivory. The most plausible hypotheses so far associate the muroid forestomach and its microbiome with a generic protective role against microbial or fungal toxins and diseases, without evident correlates of a peculiar need for this function under specific ecological conditions. Yet, this function remains to be confirmed. While providing a catalog of published depictions and hypotheses, this study highlights that the function of the muroid rodent forestomach remains enigmatic to date.
Topics: Animals; Body Size; Epithelium; Phylogeny; Rodentia; Stomach
PubMed: 35830587
DOI: 10.1002/jmor.21496 -
Biology Letters Feb 2022Puffer and porcupine fishes (families Diodontidae and Tetraodontidae, order Tetradontiformes) are known for their extraordinary ability to triple their body size by...
Puffer and porcupine fishes (families Diodontidae and Tetraodontidae, order Tetradontiformes) are known for their extraordinary ability to triple their body size by swallowing and retaining large amounts of seawater in their accommodating stomachs. This inflation mechanism provides a defence to predation; however, it is associated with the secondary loss of the stomach's digestive function. Ingestion of alkaline seawater during inflation would make acidification inefficient (a potential driver for the loss of gastric digestion), paralleled by the loss of acid-peptic genes. We tested the hypothesis of stomach inflation as a driver for the convergent evolution of stomach loss by investigating the gastric phenotype and genotype of four distantly related stomach inflating gnathostomes: sargassum fish, swellshark, bearded goby and the pygmy leatherjacket. Strikingly, unlike in the puffer/porcupine fishes, we found no evidence for the loss of stomach function in sargassum fish, swellshark and bearded goby. Only the pygmy leatherjacket (Monochanthidae, Tetraodontiformes) lacked the gastric phenotype and genotype. In conclusion, ingestion of seawater for inflation, associated with loss of gastric acid secretion, is restricted to the Tetraodontiformes and is not a selective pressure for gastric loss in other reported gastric inflating fishes.
Topics: Animals; Digestion; Fishes; Humans; Perciformes; Seawater; Stomach
PubMed: 35104429
DOI: 10.1098/rsbl.2021.0583 -
Annual International Conference of the... Jul 2023A framework to simulate the flow in the stomach using subject-specific motility patterns and geometries was developed. Dynamic 2D magnetic resonance images (MRIs) were...
A framework to simulate the flow in the stomach using subject-specific motility patterns and geometries was developed. Dynamic 2D magnetic resonance images (MRIs) were obtained. Motility parameters such as contraction speed and occlusion were quantified, and 3D stomach geometries were reconstructed using a semi-automated approach. Computational fluid dynamics (CFD) simulations were performed, and flow patterns were investigated. The stomach of both subjects had distinct anatomical features with computed volumes of 789 mL and 619 mL. For the one subject, the occlusion (i.e., normalized contraction size) was 12% while it was around 25% for the other subject. Contraction speeds were also different (1.9-2.8 mm/s vs 3.0-5.1 mm/s) for each subject. CFD simulations resulted in unsteady laminar flow for both subjects with average velocities of 2.1 and 3.2 mm/s. While antegrade flow was mainly observed in the simulations, a retropulsive jet was also present in both stomachs. The versatile framework developed within this study would allow the generation of CFD models of gastric motility from dynamic MRIs.Clinical Relevance- Subject-specific models of flow patterns informed by gastric motility features can elucidate the impact of contractions and anatomical variations on digestion. Such models can inform therapies to treat gastric dysfunctions and improve their efficacy.
Topics: Humans; Computer Simulation; Magnetic Resonance Imaging; Stomach; Hydrodynamics; Vascular Diseases
PubMed: 38083297
DOI: 10.1109/EMBC40787.2023.10340717 -
American Journal of Obstetrics &... Jan 2021A sonographically large fetal stomach has been associated with gastrointestinal obstruction, per case reports, and is often followed up with serial ultrasound...
BACKGROUND
A sonographically large fetal stomach has been associated with gastrointestinal obstruction, per case reports, and is often followed up with serial ultrasound examinations. The frequency of this phenomenon has not been systematically studied, resulting in challenges in counseling parents about the prognosis and making cost-benefit analysis of serial ultrasound follow-up difficult to assess.
OBJECTIVE
This study aimed to determine the frequency at which an enlarged fetal stomach as the sole abnormality on fetal ultrasound reflects a bowel obstruction to aid in parental counseling and determine the best practice for follow-up.
STUDY DESIGN
We performed a retrospective cohort study of all prenatal sonographic cases in which a large fetal stomach was visualized between January 1, 2002, and June 1, 2016. The inclusion criteria required a fetal diagnosis of a large stomach, defined as an increased measurement in ≥2 dimensions based on a nomogram, that resulted in a liveborn delivery within the Johns Hopkins Health System. We excluded pregnancy loss, pregnancy termination, and cases delivered outside of the Johns Hopkins Health System. Cases were subclassified as isolated or complex based on the absence or presence of additional ultrasound findings at initial presentation of the enlarged stomach. The perinatal outcomes and maternal demographics were determined and compared between isolated and complex cases.
RESULTS
Of 57,346 total cases with ultrasound examinations in the Johns Hopkins Health System within the study time frame, 348 fetuses had enlarged stomachs, with 241 (69.3%) who met the inclusion criteria as follows: 161 (66.8%) isolated and 80 (33.2%) complex. Of the 161 isolated cases, 1 resulted in neonatal small bowel obstruction (0.62%). Of note, 158 of the isolated large stomach cases (98.1%) had no postnatal abnormalities of any kind. Of the 80 complex cases, 18 (22.5%) resulted in neonatal gastrointestinal obstruction (14 cases of duodenal atresia and 4 cases of jejunal atresia). Those with isolated findings were significantly less likely to deliver preterm (n=24 [14.9%] vs n=35 [43.8%]; P<.001), be complicated by polyhydramnios (n=18 [11.2%] vs n=23 [28.8%]; P<.001), have a neonatal intensive care unit admission (n=31 [19.3%] vs n=76 [95.0%]; P<.01), or have a major surgical procedure (n=2 [1.2%] vs n=66 [82.5]; P<.001) compared with complex cases.
CONCLUSION
We found that 0.62% of isolated large fetal stomachs (1 of 161) were associated with neonatal intestinal obstruction. Of the complex cases with an enlarged stomach, 18 of 80 (22.5%) were found to have a gastrointestinal obstruction; by definition, none of these complex cases began as an isolated large stomach as their initial ultrasound finding, but rather had other concurrent sonographic abnormalities, including a double bubble sign and intestinal dilation. With a prevalence of <1% resulting in the development of a small bowel obstruction, our results suggest that, when isolated, a large stomach does not seem to warrant serial prenatal ultrasound follow-up or postnatal imaging and is likely to reflect an incidental finding.
Topics: Duodenal Obstruction; Female; Humans; Infant; Infant, Newborn; Intestinal Atresia; Pregnancy; Retrospective Studies; Stomach; Ultrasonography, Prenatal
PubMed: 33451621
DOI: 10.1016/j.ajogmf.2020.100272