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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2013

Radiation Dose and Subsequent Risk for Stomach Cancer in Long-term Survivors of Cervical Cancer

Purpose: To assess the dose–response relationship for stomach cancer after radiation therapy for cervical cancer. Methods and Materials: We conducted a nested, matched case–control study of 201 cases and 378 controls among 53,547 5-year survivors of cervical cancer diagnosed from 1943 to 1995, from 5 international, population-based cancer registries. We estimated individual radiation doses to the site of the stomach cancer for all cases and to corresponding sites for the matched controls (overall mean stomach tumor dose, 2.56 Gy, range 0.03-46.1 and after parallel opposed pelvic fields, 1.63 Gy, range 0.12-6.3). Results: More than 90% of women received radiation therapy, mostly with external beam therapy in combination with brachytherapy. Stomach cancer risk was nonsignificantly increased (odds ratio 1.27-2.28) for women receiving between 0.5 and 4.9 Gy to the stomach cancer site and significantly increased at doses ≥5 Gy (odds ratio 4.20, 95% confidence interval 1.41-13.4, P{sub trend}=.047) compared with nonirradiated women. A highly significant radiation dose–response relationship was evident when analyses were restricted to the 131 cases (251 controls) whose stomach cancer was located in the middle and lower portions of the stomach (P{sub trend}=.003), whereas there was no indication of increasing risk with increasing dose for 30 cases (57 controls) whose cancer was located in the upper stomach (P{sub trend}=.23). Conclusions: Our findings show for the first time a significant linear dose–response relationship for risk of stomach cancer in long-term survivors of cervical cancer.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2012

Analysis of Stomach and Gut Microbiomes of the Eastern Oyster (Crassostrea virginica) from Coastal Louisiana, USA

In this paper, we used high throughput pyrosequencing to characterize stomach and gut content microbiomes of Crassostrea virginica, the Easter oyster, obtained from two sites, one in Barataria Bay (Hackberry Bay) and the other in Terrebonne Bay (Lake Caillou), Louisiana, USA. Stomach microbiomes in oysters from Hackberry Bay were overwhelmingly dominated by Mollicutes most closely related to Mycoplasma; a more rich community dominated by Planctomyctes occurred in Lake Caillou oyster stomachs. Gut communities for oysters from both sites differed from stomach communities, and harbored a relatively diverse assemblage of phylotypes. Phylotypes most closely related to Shewanella and a Chloroflexi strain dominated the Lake Caillou and Hackberry Bay gut microbiota, respectively. While many members of the stomach and gut microbiomes appeared to be transients or opportunists, a putative core microbiome was identified based on phylotypes that occurred in all stomach or gut samples only. The putative core stomach microbiome comprised 5 OTUs in 3 phyla, while the putative core gut microbiome contained 44 OTUs in 12 phyla. These results collectively revealed novel microbial communities within the oyster digestive system, the functions of the oyster microbiome are largely unknown. Finally, a comparison of microbiomes from Louisiana oysters with bacterial communities reported for other marine invertebrates and fish indicated that molluscan microbiomes were more similar to each other than to microbiomes of polychaetes, decapods and fish.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2013

In silico analysis of stomach lineage specific gene set expression pattern in gastric cancer

Highlights: •Identified stomach lineage specific gene set (SLSGS) was found to be under expressed in gastric tumors. •Elevated expression of SLSGS in gastric tumor is a molecular predictor of metabolic type gastric cancer. •In silico pathway scanning identified estrogen-α signaling is a putative regulator of SLSGS in gastric cancer. •Elevated expression of SLSGS in GC is associated with an overall increase in the survival of GC patients. -- Abstract: Stomach lineage specific gene products act as a protective barrier in the normal stomach and their expression maintains the normal physiological processes, cellular integrity and morphology of the gastric wall. However, the regulation of stomach lineage specific genes in gastric cancer (GC) is far less clear. In the present study, we sought to investigate the role and regulation of stomach lineage specific gene set (SLSGS) in GC. SLSGS was identified by comparing the mRNA expression profiles of normal stomach tissue with other organ tissue. The obtained SLSGS was found to be under expressed in gastric tumors. Functional annotation analysis revealed that the SLSGS was enriched for digestive function and gastric epithelial maintenance. Employing a single sample prediction method across GC mRNA expression profiles identified the under expression of SLSGS in proliferative type and invasive type gastric tumors compared to the metabolic type gastric tumors. Integrative pathway activation prediction analysis revealed a close association between estrogen-α signaling and SLSGS expression pattern in GC. Elevated expression of SLSGS in GC is associated with an overall increase in the survival of GC patients. In conclusion, our results highlight that estrogen mediated regulation of SLSGS in gastric tumor is a molecular predictor of metabolic type GC and prognostic factor in GC.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2015

An evaluation of in vivo models for toxicokinetics of hexavalent chromium in the stomach

Hexavalent chromium (Cr6) is a drinking water contaminant that has been detected in most of the water systems throughout the United States. In 2-year drinking water bioassays, the National Toxicology Program (NTP) found clear evidence of carcinogenic activity in male and female rats and mice. Because reduction of Cr6 to trivalent chromium (Cr3) is an important detoxifying step in the gastrointestinal (GI) tract prior to systemic absorption, models have been developed to estimate the extent of reduction in humans and animals. The objective of this work was to use a revised model of ex vivo Cr6 reduction kinetics in gastric juice to analyze the potential reduction kinetics under in vivo conditions for mice, rats and humans. A published physiologically-based pharmacokinetic (PBPK) model was adapted to incorporate the new reduction model. This paper focuses on the toxicokinetics of Cr6 in the stomach compartment, where most of the extracellular Cr6 reduction is believed to occur in humans. Within the range of doses administered by the NTP bioassays, neither the original nor revised models predict saturation of stomach reducing capacity to occur in vivo if applying default parameters. However, both models still indicate that mice exhibit the lowest extent of reduction in the stomach, meaning that a higher percentage of the Cr6 dose may escape stomach reduction in that species. Similarly, both models predict that humans exhibit the highest extent of reduction at low doses. - Highlights: • We outline a new in vivo model for hexavalent chromium reduction in the stomach. • We examine in vivo reduction for mice, rats, and humans under varying conditions. • Species differences in toxicokinetics may explain susceptibility. • We show that a simplified stomach reduction model is adequate for extrapolation. • Internal dose uncertainties still exist.

60 APPLIED LIFE SCIENCES↗
NASA NTRS1990

Functional disorders of the stomach

Gastroenterologists frequently encounter patients who report vague epigastric discomforts or sensations of fullness, bloating, and distention in the upper abdomen. The discomfort is neither burning in character nor severe in intensity; there is no nocturnal pain. The epigastric location of discomfort and lack of radiation may help to exclude biliary tract and pancreatic diseases. Nausea may be present, but there is little or no vomiting. After these patients ingest liquids or solid foods, the symptoms of easy filling or early satiety and increasing discomfort and nausea are almost always present. The patient may only report "indigestion," but a specific chief complaint, such as pain, discomfort, nausea, or bloating may be elicited with further inquiries. Solid foods usually provoke more symptoms than do liquids. Symptoms of early satiety, nausea, bloating, and abdominal discomfort may culminate in the vomiting of undigested food. These vague upper gastrointestinal (GI) symptoms have been termed "dyspepsia." When peptic diseases of the stomach are excluded, the symptom complex has been called "nonulcer" dyspepsia, a vague syndrome with symptoms attributed to stomach dysfunction. Nonulcer dyspepsia has been reviewed recently. Such symptoms, commonly attributed to a "functional" disorder, are very common in clinical practice, with an incidence of 30% of patients. In this review, we will discuss an approach to the evaluation and treatment of patients with symptoms of nausea, early satiety, bloating, and vague epigastric discomfort--dyspeptic symptoms associated with functional stomach disorders. We will review the anatomy and motility of the stomach and suggest potential neuromuscular malfunctions of the stomach that may result in epigastric symptoms. The potential role of stress and other brain-gut interactions, which may underlie these symptoms, will also be reviewed.

Non-NASA Center↗
DOE OSTI2013

Establishment of a long-term three-dimensional primary culture of mouse glandular stomach epithelial cells within the stem cell niche

Highlights: ► We established a 3D culture system to allow long-term culture of stomach cells. ► In this culture system, gastric epithelial cells grew for about 3 months. ► The cultured cells differentiated into multi-units of the stomach. ► This culture method should be useful for elucidating the cause of gastric diseases. -- Abstract: Compared to the small intestine and colon, little is known about stem cells in the stomach because of a lack of specific stem cell markers and an in vitro system that allows long-term culture. Here we describe a long-term three-dimensional (3D) primary gastric culture system within the stem cell niche. Glandular stomach cells from neonatal mice cultured in collagen gel yielded expanding sphere-like structures for 3 months. The wall of the gastrospheres consisted of a highly polarized epithelial monolayer with an outer lining of myofibroblasts. The epithelial cells showed a tall columnar cell shape, basal round nuclei, and mucus-filled cytoplasm as well as expression of MUC5AC, indicating differentiation into gastric surface mucous cells. These cells demonstrated the features of fully differentiated gastric surface mucous cells such as microvilli, junctional complexes, and glycogen and secretory granules. Fewer than 1% of cultured epithelial cells differentiated into enteroendocrine cells. Active proliferation of the epithelial cells and many apoptotic cells in the inner lumen revealed the rapid cell turnover in gastrospheres in vitro. This method enables us to investigate the role of signaling between cell–cell and epithelial–mesenchymal interactions in an environment that is extremely similar to the in vivo environment.

60 APPLIED LIFE SCIENCES↗
NASA NTRS1979

Effects of ingestion of cold and hot water on the course of thermal changes in the stomach and intestine

With the use of a thermocouple and mirror galvanometer, calibrated before the experiment and after each test, it was found that the normal temperature in the esophagus is 0.1-0.4 C higher than in the oral cavity, the temperature in the duodenum is somewhat less than in the stomach, but higher with cholecystitis, duodenitis or gastritis, the temperature in the normal stomach equals or is somewhat higher than in the esophagus, and that the temperature of distended stomachs frequently is lower than in the esophagus. It was found that hot water is retained in the stomach longer than cold water, and that both hot and cold water are allowed to pass into the duodenum when the water temperature becomes approximately equal to that of the surrounding organs.

Batinkov, Y. L.↗
DOE OSTI2011

Structural investigation of porcine stomach mucin by X-ray fiber diffraction and homology modeling

Research highlights: {yields} Techniques to get oriented mucin fibre. {yields} X-ray fibre diffraction pattern for mucin. {yields} Molecular modeling of mucin based on X-ray fibre diffraction pattern. -- Abstract: The basic understanding of the three dimensional structure of mucin is essential to understand its physiological function. Technology has been developed to achieve orientated porcine stomach mucin molecules. X-ray fiber diffraction of partially orientated porcine stomach mucin molecules show d-spacing signals at 2.99, 4.06, 4.22, 4.7, 5.37 and 6.5 A. The high intense d-spacing signal at 4.22 A is attributed to the antiparallel {beta}-sheet structure identified in the fraction of the homology modeled mucin molecule (amino acid residues 800-980) using Nidogen-Laminin complex structure as a template. The X-ray fiber diffraction signal at 6.5 A reveals partial organization of oligosaccharides in porcine stomach mucin. This partial structure of mucin will be helpful in establishing a three dimensional structure for the whole mucin molecule.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

Radiologic Percutaneous Gastrostomy in Nondistended Stomach: A Modified Approach

IntroductionGastrostomy tube placement for patients requiring long-term nutritional support may be performed using different techniques including endoscopic, surgical, and percutaneous radiologically guided methods. Radiologically inserted gastrostomy (RIG), typically performed when percutaneous endoscopic gastrostomy is not possible, requires proper gastric distension that is achieved by insufflating air through a nasogastric tube. We describe a simple technique to prevent air escape from the stomach during gastrostomy tube placement. To the best of our knowledge, this technique has not yet been described in the literature.Materials and MethodsFour patients with unsuccessful percutaneous endoscopic gastrostomy were referred for fluoroscopic-guided gastrostomy. One patient had a pyriform sinus tumor and three had an ischemic stroke causing dysphagia. Gastric distention was not achieved in the patients due to air escaping into the bowel during the standard RIG procedure. A modified approach using a balloon catheter inflated in the pylorus to avoid air passing into the duodenum permitted successful RIG.ResultsThe modified RIG procedure was successfully carried out in all cases without complications.DiscussionInadequate air distension of the stomach is an unusual event that causes a failure of gastrostomy tube placement and an increased risk of both major and minor complications. The use of a balloon catheter inflated in the first part of the duodenum prevents the air passage into the bowel allowing the correct positioning of the gastrostomy.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2011

In vitro and in vivo studies on antitumor effects of gossypol on human stomach adenocarcinoma (AGS) cell line and MNNG induced experimental gastric cancer

Highlights: {yields} Gossypol is a well known polyphenolic compound used for anticancer studies but we are the first to report that gossypol has antitumor effect on MNNG induced gastric cancer in experimental animal models. {yields} Our study shows that gossypol inhibits the proliferation of AGS (human gastric adenocarcinoma) cell line. {yields} In animal models, gossypol extends the survival of cancer bearing animals and also protects the cells from carcinogenic effect. {yields} So we suggest that gossypol would be a potential chemotherapeutic and chemopreventive agent for gastric cancer. -- Abstract: The present study has evaluated the chemopreventive effects of gossypol on N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-induced gastric carcinogenesis and on human gastric adenocarcinoma (AGS) cell line. Gossypol, C{sub 30}H{sub 30}O{sub 8}, is a polyphenolic compound that has anti proliferative effect and induces apoptosis in various cancer cells. The aim of this work was to delineate in vivo and in vitro anti-initiating mechanisms of orally administered gossypol in target (stomach) tissues and in human gastric adenocarcinoma (AGS) cell line. In vitro results prove that gossypol has potent cytotoxic effect and inhibit the proliferation of adenocarcinoma (AGS) cell line. In vivo results prove gossypol to be successful in prolonging the survival of MNNG induced cancer bearing animals and in delaying the onset of tumor in animals administrated with gossypol and MNNG simultaneously. Examination of the target (stomach) tissues in sacrificed experimental animals shows that administration of gossypol significantly reduces the level of tumor marker enzyme (carcino embryonic antigen) and pepsin. The level of Nucleic acid contents (DNA and RNA) significantly reduces, and the membrane damage of glycoprotein subsides, in the target tissues of cancer bearing animals, with the administration of gossypol. These data suggest that gossypol may create a beneficial effect in patients with gastric cancer.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2014

Metastatic Melanoma Induced Metabolic Changes in C57BL/6J Mouse Stomach Measured by 1H NMR Spectroscopy

Melanoma is a malignant tumor of melanocytes with high capability of invasion and rapid metastasis to other organs. Malignant melanoma is the most common metastatic malignancy found in gastrointestinal tract (GI). To the best of our knowledge, previous studies of melanoma in gastrointestinal tract are all clinical case reports. In this work, 1H NMR-based metabolomics approach is used to investigate the metabolite profiles differences of stomach tissue extracts of metastatic B16-F10 melanoma in C57BL/6J mouse and search for specific metabolite biomarker candidates. Principal Component Analysis (PCA), an unsupervised multivariate data analysis method, is used to detect possible outliers, while Orthogonal Projection to Latent Structure (OPLS), a supervised multivariate data analysis method, is employed to evaluate important metabolites responsible for discriminating the control and the melanoma groups. Both PCA and OPLS results reveal that the melanoma group can be well separated from its control group. Among the 50 identified metabolites, it is found that the concentrations of 19 metabolites are statistically and significantly changed with the levels of O-phosphocholine and hypoxanthine down-regulated while the levels of isoleucine, leucine, valine, isobutyrate, threonine, cadaverine, alanine, glutamate, glutamine, methionine, citrate, asparagine, tryptophan, glycine, serine, uracil, and formate up-regulated in the melanoma group. These significantly changed metabolites are associated with multiple biological pathways and may be potential biomarkers for metastatic melanoma in stomach.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2019

Fluoroscopy-Guided Peroral Placement of a Self-Expandable Metallic Stent for Malignant Jejunal Obstruction in a Non-surgically Altered Stomach

Malignant small bowel obstruction is a common and distressing complication in advanced cancer patients. Recently, stent placement was reported to be a safe and effective alternative treatment. However, there are only a few case reports associated with stent placement in malignant jejunal obstruction. Furthermore, most patients had a history of gastrectomy before stent placement, which shortens the catheterization pathway. In our case series, we present five cases of malignant proximal jejunal obstruction in a non-surgically altered stomach in the management of fluoroscopy-guided self-expandable metallic stent placement and discuss the interventional management and clinical outcomes. Level of Evidence: Level 4, Case Series.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2015

Prostaglandin potentiates 5-HT responses in stomach and ileum innervating visceral afferent sensory neurons

Highlights: • Prostaglandin E2 (PGE{sub 2}) effect was tested on visceral afferent neurons. • PGE{sub 2} did not evoke response but potentiated serotonin (5-HT) currents up to 167%. • PGE{sub 2}-induced potentiation was blocked by E-prostanoid type 4 receptors antagonist. • PGE{sub 2} effect on 5-HT response was also blocked by protein kinase A inhibitor KT5720. • Thus, PGE{sub 2} modulate visceral afferent neurons via synergistic signaling with 5-HT. - Abstract: Gastrointestinal disorder is a common symptom induced by diverse pathophysiological conditions that include food tolerance, chemotherapy, and irradiation for therapy. Prostaglandin E{sub 2} (PGE{sub 2}) level increase was often reported during gastrointestinal disorder and prostaglandin synthetase inhibitors has been used for ameliorate the symptoms. Exogenous administration of PGE{sub 2} induces gastrointestinal disorder, however, the mechanism of action is not known. Therefore, we tested PGE{sub 2} effect on visceral afferent sensory neurons of the rat. Interestingly, PGE{sub 2} itself did not evoked any response but enhanced serotonin (5-HT)-evoked currents up to 167% of the control level. The augmented 5-HT responses were completely inhibited by a 5-HT type 3 receptor antagonist, ondansetron. The PGE{sub 2}-induced potentiation were blocked by a selective E-prostanoid type4 (EP{sub 4}) receptors antagonist, L-161,982, but type1 and 2 receptor antagonist AH6809 has no effect. A membrane permeable protein kinase A (PKA) inhibitor, KT5720 also inhibited PGE{sub 2} effects. PGE{sub 2} induced 5-HT current augmentation was observed on 15% and 21% of the stomach and ileum projecting neurons, respectively. Current results suggest a synergistic signaling in visceral afferent neurons underlying gastrointestinal disorder involving PGE{sub 2} potentiation of 5-HT currents. Our findings may open a possibility for screen a new type drugs with lower side effects than currently using steroidal prostaglandin synthetase inhibitors by selectively targeting EP{sub 4} receptor/PKA pathway without interrupt prostaglandin synthesis.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2011

The origin of pre-neoplastic metaplasia in the stomach: Chief cells emerge from the Mist

The digestive-enzyme secreting, gastric epithelial chief (zymogenic) cell is remarkable and underappreciated. Here, we discuss how all available evidence suggests that mature chief cells in the adult, mammalian stomach are postmitotic, slowly turning over cells that arise via a relatively long-lived progenitor, the mucous neck cell, The differentiation of chief cells from neck cells does not involve cell division, and the neck cell has its own distinct pattern of gene expression and putative physiological function. Thus, the ontogeny of the normal chief cell lineage exemplifies transdifferentiation. Furthermore, under pathophysiogical loss of acid-secreting parietal cell, the chief cell lineage can itself trasndifferentiate into a mucous cell metaplasia designated Spasmolytic Polypeptide Expressing Metaplasia (SPEM). Especially in the presence of inflammation, this metaplastic lineage can regain proliferative capacity and, in humans may also further differentiate into intestinal metaplasia. The results indicate that gastric fundic lineages display remarkable plasticity in both physiological ontogeny and pathophysiological pre-neoplastic metaplasia.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2015

Modification of Helicobacter pylori peptidoglycan enhances NOD1 activation and promotes cancer of the stomach

Helicobacter pylori is the strongest known risk factor for gastric carcinogenesis. One cancer-linked locus is the cag pathogenicity island, which translocates components of peptidoglycan (PGN) into host cells. NOD1 is an intracellular immune receptor that senses PGN from Gram-negative bacteria and responds by inducing autophagy and activating NF-κB, leading to inflammation-mediated bacterial clearance; however chronic pathogens can evade NOD1-mediated clearance by altering PGN structure. We previously demonstrated that the H. pylori cag + strain 7.13 rapidly induces gastric cancer in Mongolian gerbils. Using 2D-DIGE and mass spectrometry, we identified a novel mutation within the gene encoding the peptidoglycan deacetylase PgdA; therefore, we sought to define the role of H. pylori PgdA in NOD1-dependent activation of NF-κB, inflammation, and cancer. Co-culture of H. pylori strain 7.13 or its pgdA $-$ isogenic mutant with AGS gastric epithelial cells or HEK293 epithelial cells expressing a NF-κB reporter revealed that pgdA inactivation significantly decreased NOD1-dependent NF-κB activation and autophagy. Infection of Mongolian gerbils with an H. pylori pgdA $-$ mutant strain led to significantly decreased levels of inflammation and malignant lesions in the stomach; however, pre-activation of NOD1 prior to bacterial challenge reciprocally suppressed inflammation and cancer in response to wild-type H. pylori . Expression of NOD1 differs in human gastric cancer specimens compared to non-cancer samples harvested from the same patients. In conclusion, these results indicate that PGN deacetylation plays an important role in modulating host inflammatory responses to H. pylori , allowing the bacteria to persist and induce carcinogenic consequences in the gastric niche.

59 BASIC BIOLOGICAL SCIENCES↗