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Sample records for microsphere induced gastrointestinal

  1. Laser-Induced Spallation of Microsphere Monolayers.

    PubMed

    Hiraiwa, Morgan; Stossel, Melicent; Khanolkar, Amey; Wang, Junlan; Boechler, Nicholas

    2016-08-01

    The detachment of a semiordered monolayer of polystyrene microspheres adhered to an aluminum-coated glass substrate is studied using a laser-induced spallation technique. The microsphere-substrate adhesion force is estimated from substrate surface displacement measurements obtained using optical interferometry, and a rigid-body model that accounts for the inertia of the microspheres. The estimated adhesion force is compared with estimates obtained using an adhesive contact model together with interferometric measurements of the out-of-plane microsphere contact resonance, and with estimated work of adhesion values for the polystyrene-aluminum interface. Scanning electron microscope images of detached monolayer regions reveal a unique morphology, namely, partially detached monolayer flakes composed of single hexagonal close packed crystalline domains. This work contributes to the fields of microsphere adhesion and contact dynamics, and demonstrates a unique monolayer delamination morphology. PMID:27409715

  2. Lanthanum-Induced Gastrointestinal Histiocytosis

    PubMed Central

    Araya, Hiwot; Longacre, Teri A.; Pasricha, Pankaj J.

    2015-01-01

    A patient with end-stage renal disease (ESRD) on hemodialysis presented with fever, anorexia, and nausea shortly after starting oral lanthanum carbonate for phosphate control. Gastric and duodenal biopsies demonstrated diffuse histiocytosis with intracellular aggregates of basophilic foreign material. Transmission electron microscopy, an underutilized diagnostic test, revealed the nature of the aggregates as heavy metal particles, consistent with lanthanum. Symptoms and histiocytosis improved after discontinuation of lanthanum. Lanthanum may be an underdiagnosed cause of gastrointestinal histiocytosis. PMID:26157959

  3. Microspheres

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Vital information on a person's physical condition can be obtained by identifying and counting the population of T-cells and B-cells, lymphocytes of the same shape and size that help the immune system protect the body from the invasion of disease. The late Dr. Alan Rembaum developed a method for identifying the cells. The method involved tagging the T-cells and B-cells with microspheres of different fluorescent color. Microspheres, which have fluorescent dye embedded in them, are chemically treated so that they can link with antibodies. With the help of a complex antibody/antigen reaction, the microspheres bind themselves to specific 'targets,' in this case the T-cells or B-cells. Each group of cells can then be analyzed by a photoelectronic instrument at different wavelengths emitted by the fluorescent dyes. Same concept was applied to the separation of cancer cells from normal cells. Microspheres were also used to conduct many other research projects. Under a patent license Magsphere, Inc. is producing a wide spectrum of microspheres on a large scale and selling them worldwide for various applications.

  4. Piperine containing floating microspheres: an approach for drug targeting to the upper gastrointestinal tract.

    PubMed

    Khatri, Smriti; Awasthi, Rajendra

    2016-06-01

    The purpose of this investigation was to prepare and characterize acyclovir loaded floating microspheres by emulsification solvent evaporation method. Piperine was added to investigate its effect on acyclovir bioavailability. The microspheres were characterized for size, shape, entrapment efficiency, in vitro drug release, and in vivo pharmacokinetic parameters. The morphological characterization of microspheres was done using a scanning electron microscope. The microspheres were spherical and had particle size in the range of 400 to 525 μm. The percent drug entrapment efficiency varied between 56.12 ± 1.32 % to 87.32 ± 5.28 %. The drug release was decreased at higher polymer concentrations. Nearly two times higher AUC0-24 value of acyclovir-loaded piperine containing microspheres (15614.13 ± 6953.13 ng h ml(-1)) was observed as compared to the drug solution (7552.33 ± 3219.09 ng h ml(-1)). Under the accelerated storage conditions, the best selected formulation was found to be stable for 90 days. The preliminary results of this study suggest that the developed microspheres containing acyclovir could enhance drug entrapment efficiency, reduce initial burst release, and prolong the drug release with enhanced bioavailability. PMID:26902907

  5. Asbestos-Induced Gastrointestinal Cancer: An Update

    PubMed Central

    Kim, Seok Jo; Williams, David; Cheresh, Paul; Kamp, David W

    2016-01-01

    Asbestos-related diseases, such as malignancies and asbestosis, remain a significant occupational and public health concern. Asbestos is still widely used in many developing countries despite being a recognized carcinogen that has been banned over 50 countries. The prevalence and mortality from asbestos-related diseases continue to pose challenges worldwide. Many countries are now experiencing an epidemic of asbestos-related disease that is the legacy of occupational exposure during the 20th century because of the long latency period (up to 40 years) between initial asbestos exposure and exhibition of disease. However, the gastrointestinal (GI) cancers resulting from asbestos exposure are not as clearly defined. In this review, we summarize some of the recent epidemiology of asbestos-related diseases and then focus on the evidence implicating asbestos in causing GI malignancies. We also briefly review the important new pathogenic information that has emerged over the past several years that may account for asbestos-related gastrointestinal cancers. All types of asbestos fibers have been implicated in the mortality and morbidity from GI malignancies but the collective evidence to date is mixed. Although the molecular basis of GI cancers arising from asbestos exposure is unclear, there have been significant advances in our understanding of mesothelioma and asbestosis that may contribute to the pathophysiology underlying asbestos-induced GI cancers. The emerging new evidence into the pathogenesis of asbestos toxicity is providing insights into the molecular basis for developing novel therapeutic strategies for asbestos-related diseases in future management. PMID:27158561

  6. Protective effects of alginate–chitosan microspheres loaded with alkaloids from Coptis chinensis Franch. and Evodia rutaecarpa (Juss.) Benth. (Zuojin Pill) against ethanol-induced acute gastric mucosal injury in rats

    PubMed Central

    Wang, Qiang-Song; Zhu, Xiao-Ning; Jiang, Heng-Li; Wang, Gui-Fang; Cui, Yuan-Lu

    2015-01-01

    Zuojin Pill (ZJP), a traditional Chinese medicine formula, consists of Coptis chinensis Franch. and Evodia rutaecarpa (Juss.) Benth. in a ratio of 6:1 (w/w) and was first recorded in “Danxi’s experiential therapy” for treating gastrointestinal disorders in the 15th century. However, the poor solubility of alkaloids from ZJP restricted the protective effect in treating gastritis and gastric ulcer. The aim of the study was to investigate the protective mechanism of mucoadhesive microspheres loaded with alkaloids from C. chinensis Franch. and E. rutaecarpa (Juss.) Benth. on ethanol-induced acute gastric mucosal injury in rats. Surface morphology, particle size, drug loading, encapsulation efficiency, in vitro drug release, mucoadhesiveness, and fluorescent imaging of the microspheres in gastrointestinal tract were studied. The results showed that the mucoadhesive microspheres loaded with alkaloids could sustain the release of drugs beyond 12 hours and had gastric mucoadhesive property with 82.63% retention rate in vitro. The fluorescence tracer indicated high retention of mucoadhesive microspheres within 12 hours in vivo. The mucoadhesive microspheres loaded with alkaloids could reduce the gastric injury by decreasing the mucosal lesion index, increasing the percentage of inhibition and increasing the amount of mucus in the gastric mucosa in an ethanol-induced gastric mucosal injury rat model. Moreover, the mucoadhesive microspheres loaded with alkaloids reduce the inflammatory response by decreasing the levels of tumor necrosis factor-α (TNF-α), interleukin 1β (IL-1β), downregulating the mRNA expression of inducible nitric oxide synthase, TNF-α, and IL-1β in gastric mucosa. All the results indicate that mucoadhesive microspheres loaded with alkaloids could not only increase the residence time of alkaloids in rat stomach, but also exert gastroprotective effects through reducing the inflammatory response on ethanol-induced gastric mucosal damage. Thus

  7. Uniform and amorphous rifampicin microspheres obtained by freezing induced LLPS during lyophilization.

    PubMed

    Liu, Chun; Kong, Chao; Wu, Guoliang; Zhu, Junhao; Javid, Babak; Qian, Feng

    2015-11-10

    By lyophilization of rifampicin (RIF) solution in TBA/water with various solvent compositions, uniform and amorphous rifampicin (RIF) microspheres were produced. Using 55% TBA solution, the obtained RIF microspheres have a mono-dispersive size distribution with diameters range from 1 to 3 μm. The RIF microspheres are found to be amorphous by X-ray diffraction, and are expected to dissolve much faster than the crystalline RIF upon inhalation. Mechanistic investigation revealed that the amorphous RIF microspheres were formed due to liquid-liquid phase separation (LLPS) occurred during the freezing of the TBA/water solution. We also observed that the RIF microspheres can be readily phagocytized by activated THP-1 cells within 15 min. The suitable size distribution, high solubility, and readiness for phagocytosis by macrophages, all suggest that the lyophilized amorphous RIF microspheres could be potentially used as an anti-tuberculosis inhalation therapy. In addition, similar process was used to lyophilize TBA/water solutions of several other drugs, including rifaximin, rifapentine, paclitaxel, and isoniazid. We found that for drugs with appropriate physiochemical properties, such as paclitaxel and rifaximin, mono-dispersive microspheres could be obtained as well, which demonstrated that freezing induced LLPS could be utilized as a novel particle engineering methodology to produce drug microspheres by lyophilization. PMID:26383842

  8. Biodegradable polylactide microspheres enhance specific immune response induced by Hepatitis B surface antigen

    PubMed Central

    Qiu, Shaohui; Wei, Qiang; Liang, Zhenglun; Ma, Guanghui; Wang, Lianyan; An, Wenqi; Ma, Xiaowei; Fang, Xin; He, Peng; Li, Hemin; Hu, Zhongyu

    2014-01-01

    Hepatitis B (HB) infection caused by Hepatitis B virus (HBV) is the most common liver disease in the world. HB vaccine, when administered in conjunction with alum adjuvants, induces Th2 immunity that confers protection against HBV. However, currently available vaccine formulations and adjuvants do not elicit adequate Th1 and CTL responses that are important for prevention of maternal transmission of the virus. Microspheres synthesized from poly (D, L-lactide-co-glycolide) (PLGA) or poly (D, L-lactide) (PLA) polymers have been considered as promising tools for in vivo delivery of antigens and drugs. Here we describe PLA microspheres synthesized by premix membrane emulsification method and their application in formulating a new microsphere based HB vaccine. To evaluate the immunogenicity of this microsphere vaccine, BALB/c mice were immunized with microsphere vaccine and a series of immunological assays were conducted. Results of Enzyme-linked ImmunoSpot (ELISPOT) assays revealed that the number of interferon-gamma (IFN-γ)-producing splenocytes and CD8+ T cells increased significantly in the microsphere vaccine group. Microsphere vaccine group showed enhanced specific cell lysis when compared with HB surface antigen (HBsAg) only group in 51Cr cytotoxicity assays. Moreover, microsphere vaccine elicited a comparable level of antibody production as that of HB vaccine administered with alum adjuvant. We show that phagocytosis of HBsAg by dendritic cells is more pronounced in microsphere vaccine group when compared with other control groups. These results clearly demonstrate the potential of using PLA microspheres as effective HB vaccine adjuvants for an enhanced Th1 immune response. PMID:25424942

  9. Biodegradable polylactide microspheres enhance specific immune response induced by Hepatitis B surface antigen.

    PubMed

    Qiu, Shaohui; Wei, Qiang; Liang, Zhenglun; Ma, Guanghui; Wang, Lianyan; An, Wenqi; Ma, Xiaowei; Fang, Xin; He, Peng; Li, Hemin; Hu, Zhongyu

    2014-01-01

    Hepatitis B (HB) infection caused by Hepatitis B virus (HBV) is the most common liver disease in the world. HB vaccine, when administered in conjunction with alum adjuvants, induces Th2 immunity that confers protection against HBV. However, currently available vaccine formulations and adjuvants do not elicit adequate Th1 and CTL responses that are important for prevention of maternal transmission of the virus. Microspheres synthesized from poly (D, L-lactide-co-glycolide) (PLGA) or poly (D, L-lactide) (PLA) polymers have been considered as promising tools for in vivo delivery of antigens and drugs. Here we describe PLA microspheres synthesized by premix membrane emulsification method and their application in formulating a new microsphere based HB vaccine. To evaluate the immunogenicity of this microsphere vaccine, BALB/c mice were immunized with microsphere vaccine and a series of immunological assays were conducted. Results of Enzyme-linked ImmunoSpot (ELISPOT) assays revealed that the number of interferon-gamma (IFN-γ)-producing splenocytes and CD8(+) T cells increased significantly in the microsphere vaccine group. Microsphere vaccine group showed enhanced specific cell lysis when compared with HB surface antigen (HBsAg) only group in (51)Cr cytotoxicity assays. Moreover, microsphere vaccine elicited a comparable level of antibody production as that of HB vaccine administered with alum adjuvant. We show that phagocytosis of HBsAg by dendritic cells is more pronounced in microsphere vaccine group when compared with other control groups. These results clearly demonstrate the potential of using PLA microspheres as effective HB vaccine adjuvants for an enhanced Th1 immune response. PMID:25424942

  10. An Approach to the Design of a Particulate System for Oral Protein Delivery .II. Preparation and Stability Study of rhGH-Loaded Microspheres in Simulated Gastrointestinal Fluids

    PubMed Central

    Nafissi Varcheh, Nastaran; Aboofazeli, Reza

    2011-01-01

    The delivery of therapeutic proteins has gained momentum with development of biotechnology. However, large molecular weight, hydrophilic nature and susceptibility to harsh environment of gastrointestinal tract (GIT) resulted in low absorption. The main objective of this work was the design of a particulate system for oral delivery of recombinant human growth hormone (rhGH) on the basis of particle uptake mechanism in GIT. Biodegradable protein-loaded microspheres were prepared using Resomers (RG207, RG756 and RG505) by double emulsion methods. Aqueous solution of protein and freshly prepared rhGH-zinc complex were used for loading process. Various analytical methods, including fluorescence spectroscopy, SDS-PAGE electrophoresis and reversed-phase chromatography, were set up for the quantification and qualification of rhGH before and after the formulation and fabrication procedures. At the optimum conditions, microspheres were mostly below 10 μm with relatively high protein loading (> 50%). Obtained data showed that the stability of protein did not change during the formulation and microencapsulation processes. Results also showed that the encapsulation process in the presence of zinc caused no detectable change in the protein chemical stability. In-vitro stability study of microspheres in different simulated GI media indicated that the entrapped protein was physically stable. Less than 20% of rhGH was released from the microspheres incubated in both simulated stomach and intestine fluids for 3 and 6 h, respectively. PMID:24250342

  11. Effects of fructose-1,6-biphosphate on microsphere-induced cerebral ischemia in the rat.

    PubMed

    Trimarchi, G R; Arcadi, F A; Imperatore, C; Ruggeri, P; Costa, G

    1997-01-01

    Fructose-1,6-bisphosphate has been shown to exert beneficial effects in different experimental models of cerebral ischemia. In view of this evidence, we have determined whether the compound protects the brain during microsphere-induced ischemia. One thousand two hundred microspheres were injected into female rats through a catheter inserted into the right common carotid artery and, 15 minutes and again 24 hours later, we intravenously treated the animals with 333 mg Kg(-1) of fructose-1,6-bisphosphate. The injection of microspheres produced significant changes in the rats' gross behavior, in their performance in the beam walking test, and in their brain lactate concentrations. The treatment with fructose-1,6-bisphosphate significantly attenuated the behavioral alterations induced by microsphere ischemia, but not in reducing brain accumulation of lactate. Moreover, the compound was shown to ameliorate the blood-brain barrier dysfunction, produced 2 and 4 hours after microsphere injection, evaluated by the Evans blue method. These results suggest that fructose-1,6-bisphosphate possesses salutary properties against the damages induced by microsphere ischemia. PMID:9250717

  12. Fabrication of ceramic microspheres by diffusion-induced sol-gel reaction in double emulsions.

    PubMed

    Zhang, Lei; Hao, Shaochang; Liu, Bing; Shum, Ho Cheung; Li, Jiang; Chen, Haosheng

    2013-11-27

    We demonstrate an approach to prepare zirconium dioxide (ZrO2) microspheres by carrying out a diffusion-induced sol-gel reaction inside double emulsion droplets. A glass capillary microfluidic device is introduced to generate monodisperse water-in-oil-in-water (W/O/W) double emulsions with a zirconium precursor as the inner phase. By adding ammonia to the continuous aqueous phase, the zirconium precursor solution is triggered to gel inside the emulsions. The double emulsion structure enhances the uniformity in the rate of the sol-gel reaction, resulting in sol-gel microspheres with improved size uniformity and sphericity. ZrO2 ceramic microspheres are formed following subsequent drying and sintering steps. Our approach, which combines double-emulsion-templating and sol-gel synthesis, has great potential for fabricating versatile ceramic microspheres for applications under high temperature and pressure. PMID:23865771

  13. Preparation of porous microsphere-scaffolds by electrohydrodynamic forming and thermally induced phase separation.

    PubMed

    Ghanbar, Hanif; Luo, C J; Bakhshi, Poonam; Day, Richard; Edirisinghe, Mohan

    2013-07-01

    The availability of forming technologies able to mass produce porous polymeric microspheres with diameters ranging from 150 to 300 μm is significant for some biomedical applications where tissue augmentation is required. Moreover, appropriate assembly of microspheres into scaffolds is an important challenge to enable direct usage of the as-formed structures in treatments. This work reports the production of poly (glycolic-co-lactic acid) and poly (ε-caprolactone) microspheres under ambient conditions using one-step electrohydrodynamic jetting (traditionally known as atomisation) and thermally induced phase separation (TIPS). To ensure robust production for practical uses, this work presents 12 comprehensive parametric mode mappings of the diameter distribution profiles of the microspheres obtained over a broad range of key processing parameters and correlating of this with the material parameters of 5 different polymer solutions of various concentrations. Poly (glycolic-co-lactic acid) (PLGA) in Dimethyl carbonate (DMC), a low toxicity solvent with moderate conductivity and low dielectric constant, generated microspheres within the targeted diameter range of 150-300 μm. The fabrication of the microspheres suitable for formation of the scaffold structure is achieved by changing the collection method from distilled water to liquid nitrogen and lyophilisation in a freeze dryer. PMID:23623059

  14. Imaging of Drug-induced Complications in the Gastrointestinal System.

    PubMed

    McGettigan, Melissa J; Menias, Christine O; Gao, Zhenqiang J; Mellnick, Vincent M; Hara, Amy K

    2016-01-01

    Drug-induced injury commonly affects the gastrointestinal and hepatobiliary systems because of the mechanisms of absorption and metabolism. In pill esophagitis, injury is frequently related to direct contact with the esophageal mucosa, resulting in small superficial ulcers in the mid esophagus. Nonsteroidal anti-inflammatory drugs can lead to gastrointestinal tract ulcers and small bowel mucosal diaphragms (thin weblike strictures). Injury to the pancreatic and hepatobiliary systems can manifest as pancreatitis, acute or chronic hepatitis, cholestasis, or steatosis and steatohepatitis (which may progress to cirrhosis). Various drugs may also insult the hepatic vasculature, resulting in Budd-Chiari and sinusoidal obstructive syndromes. Focal lesions such as hepatic adenomas may develop after use of oral contraceptives or anabolic steroids. Ultrasonography, computed tomography, and magnetic resonance imaging can aid in diagnosis of drug-induced injuries and often are necessary to exclude other causes. PMID:26761532

  15. Ipilimumab-Induced Gastrointestinal Toxicities: A Management Algorithm.

    PubMed

    Klair, Jagpal S; Girotra, Mohit; Hutchins, Laura F; Caradine, Kari D; Aduli, Farshad; Garcia-Saenz-de-Sicilia, Mauricio

    2016-07-01

    Ipilimumab is a cytotoxic T-lymphocyte-associated antigen-4-blocking monoclonal antibody, which has shown a significant survival benefit in metastatic melanoma patients. Despite being a promising therapy for a disease with an otherwise rather dismal prognosis, it is associated with several immune-related adverse effects (IRAE) mainly targeted toward the digestive tract, skin, liver, and hypothalamic-pituitary axis. Ipilimumab-induced gastrointestinal toxicity (IGT) include diarrhea (~44 %), colitis (~18 %), bowel perforation (<1 %), and pancreatitis (<1.5 %). Early recognition of IRAE and treatment initiation are critical to decrease the risk of further complications. Management included steroids as initial therapy, followed by infliximab (anti-tumor necrosis factor alpha antibody) and/or surgical option for complications like bowel perforation. We present a series of three patients with metastatic melanoma, who received treatment with ipilimumab, and presented with varying gastrointestinal clinical manifestations and complications. Through this case series, our attempt is to make practicing gastroenterologists cognizant about the wide spectrum of gastrointestinal toxicity of this rather new clinical entity, as well as to discuss management algorithm for IGT. PMID:26846115

  16. Microwave-induced fast crystallization of amorphous hierarchical anatase microspheres.

    PubMed

    Calatayud, David G; Jardiel, Teresa; Peiteado, Marco; Caballero, Amador C; Fernández-Hevia, Daniel

    2014-01-01

    The fabrication of hierarchical anatase microspheres with potential photocatalytic properties eventually comprises a consolidation step in which a high degree of crystalline order is typically achieved through conventional electric heating treatments. This however entails a substantial reduction in the specific surface area and porosity of the powders, with the consequent deterioration in their photocatalytic response. Here, we have tested the employ of microwave heating as an alternative energy-saving sintering method to promote fast crystallization. The results obtained suggest that under the microwave radiation, the TiO2 hierarchical structures can effectively crystallize in a drastically reduced heating time, allowing the specific surface area and the porosity to be kept in the high values required for an improved photocatalytic performance. PMID:24948894

  17. Microwave-induced fast crystallization of amorphous hierarchical anatase microspheres

    PubMed Central

    2014-01-01

    The fabrication of hierarchical anatase microspheres with potential photocatalytic properties eventually comprises a consolidation step in which a high degree of crystalline order is typically achieved through conventional electric heating treatments. This however entails a substantial reduction in the specific surface area and porosity of the powders, with the consequent deterioration in their photocatalytic response. Here, we have tested the employ of microwave heating as an alternative energy-saving sintering method to promote fast crystallization. The results obtained suggest that under the microwave radiation, the TiO2 hierarchical structures can effectively crystallize in a drastically reduced heating time, allowing the specific surface area and the porosity to be kept in the high values required for an improved photocatalytic performance. PMID:24948894

  18. Metal ion-induced alginate-locust bean gum IPN microspheres for sustained oral delivery of aceclofenac.

    PubMed

    Jana, Sougata; Gandhi, Arijit; Sheet, Subrata; Sen, Kalyan Kumar

    2015-01-01

    The alginate microspheres represent a useful tool for sustained oral delivery of drugs but exhibit several problems associated with the stability and rapid release of drugs at higher pH values. To overcome these drawbacks, alginate-locust bean gum (LBG) interpenetrating microspheres were prepared by calcium ion (Ca(+2)) induced ionotropic gelation technique for prolonged release of aceclofenac. The drug entrapment efficiency of these microspheres was found to be 59-93%. The microspheres lied in the size range of 406-684μm. Scanning electron microscopy revealed spherical shape of the microspheres. No drug-polymer interaction was evident after infrared spectroscopy analysis. The microspheres provided sustained release of aceclofenac in phosphate buffer solution (pH 6.8) over a period of 8h. The drug release data were fitted into the Korsmeyer-Peppas model and the drug release was found to follow anomalous (non-Fickian) diffusion mechanism. Pharmacodynamic study of the microspheres showed a prolonged anti-inflammatory activity in carrageenan-induced rat paw model following oral administration. PMID:25111495

  19. Diet-induced thermogenesis in patients with gastrointestinal cancer cachexia.

    PubMed

    Weston, P M; King, R F; Goode, A W; Williams, N S

    1989-08-01

    1. Indirect calorimetry has been used to measure resting energy expenditure (REE) and the thermogenic response to a test meal (diet-induced thermogenesis) in groups of weight-stable and weight-losing patients with gastrointestinal adenocarcinoma. Average daily intakes of energy and protein were computed from dietary assessment for the week before hospitalization. Results were compared with a control group of patients with benign gastrointestinal disease. 2. Weight-losing cancer patients had a significantly reduced mean total energy and protein intake. 3. There was no significant difference in REE between the groups when results were normalized in terms of metabolic body size (kJ/kg 0.75) and lean body mass (kJ/kg). 4. Diet-induced thermogenesis was reduced in weight-losing cancer patients. 5. It is suggested that the reduction of diet-induced thermogenesis in weight-losing cancer patients is another element of starvation adaptation, subsequent to their weight loss, and that altered thermogenesis does not contribute to the weight loss seen in cancer cachexia. PMID:2766653

  20. Gastrointestinal motor alterations induced by precipitated benzodiazepine withdrawal in rats.

    PubMed

    Martinez, J; Fargeas, M J; Bueno, L

    1992-03-01

    The effects of benzodiazepine withdrawal on intestinal motor activity and propulsion were investigated in two groups of diazepam-dependent rats (15 mg/kg/day for 8 days). Withdrawal was precipitated by injection of two benzodiazepine antagonists (Ro 15.1788 and PK 11.95) acting on central and peripheral-type receptors, respectively. Intestinal motor activity was assessed by implanting electrodes for long-term electromyographic recordings. Gastrointestinal transit was evaluated after gavage by a marker (51CrO4Na2) and radioactivity counting. Both RO 15.1788 (15 mg/kg) and PK 11.195 (5 mg/kg) triggered an abstinence syndrome with behavioral and autonomic signs. At the intestinal level, Ro 15.1788 induced a phase of strong irregular spiking activity (173 +/- 63 min) which remained located in the duodenum. In contrast, PK 11.195 induced a period of propagated myoelectric complexes characterized by phases II and III of high amplitude. The cecal frequency was doubled during the 1st hr after withdrawal induced by the two antagonists. Both Ro 15.1788 and PK 11.195 at this dosage had no effect per se on intestinal motility in vehicle-treated rats. In the second group of rats, gastric emptying was enhanced by 49.4 and 45.6% by Ro 15.1788 and PK 11.195, respectively. In contrast, PK 11.195 was able to accelerate the intestinal transit more than did Ro 15.1788 (geometric center, 5.9 +/- 0.43 and 5.3 +/- 0.49, respectively, vs. 4.1 +/- 0.31 in control rats). Our study shows that precipitated benzodiazepine withdrawal in diazepam-dependent rats induces alterations of the intestinal myoelectrical activity leading to an increase of the gastrointestinal transit. Central and peripheral-type receptors are involved in these effects. PMID:1312156

  1. Polymeric microspheres

    DOEpatents

    Walt, David R.; Mandal, Tarun K.; Fleming, Michael S.

    2004-04-13

    The invention features core-shell microsphere compositions, hollow polymeric microspheres, and methods for making the microspheres. The microspheres are characterized as having a polymeric shell with consistent shell thickness.

  2. Heparin as a pharmacologic intervention to induce positive scintiscan in occult gastrointestinal bleeding

    SciTech Connect

    Chaudhuri, T.K.; Brantly, M.

    1984-04-01

    The value of using heparin as a pharmacologic intervention to induce a positive scintiscan was studied in a patient with chronic occult gastrointestinal bleeding. When all standard diagnostic tests (upper and lower gastrointestinal series, upper and lower endoscopy, and conventional noninterventional Tc-99m RBC imaging) fail to detect and localize gastrointestinal bleeding in a patient who has definite clinical evidence (guaiac positive stool and dropping hemoglobin, hematocrit) of chronic occult gastrointestinal oozing, heparin may be used (with proper precaution) as a last resort to aid in the scintigraphic detection and localization of chronic occult gastrointestinal bleeding.

  3. Child and parent perceived food-induced gastrointestinal symptoms and quality of life in children with functional gastrointestinal disorders

    Technology Transfer Automated Retrieval System (TEKTRAN)

    It is unknown whether children with functional gastrointestinal (GI) disorders identify specific foods that exacerbate their GI symptoms. The objectives of this study were to determine the perceived role of food on GI symptoms and to determine the impact of food-induced symptoms on quality of life (...

  4. Upper gastrointestinal bleeding: gallstone-induced auto-sphincterotomy

    PubMed Central

    Kalipershad, Sujala; Chung, Kin Tong; Jehangir, Ernest

    2012-01-01

    A 67-year-old gentleman with no significant medical history of note presented with sudden onset of epigastric pain, coffee ground vomiting and passing black tarry stool. A series of investigations including blood tests, ultrasound scan, CT abdomen and pelvis with contrast and endoscopy failed to reveal any site of active bleeding. The mystery remained and the patient continued to have upper gastrointestinal bleeding. A second CT abdomen and pelvis with contrast was carried out and showed evidence of contrast extravasation into the duodenum (figure 3). An exploratory laparotomy showed no obvious site of haemorrhage and a loop jejunostomy was performed. The diagnosis of gallstone-induced auto-sphincterotomy was only made, using gastroscope via jejunostomy, when a big gallstone was found in the third part of the duodenum and the papilla was ruptured (figure 5). PMID:22914239

  5. Antigens linked to synthetic microspheres induce immune responses in primates in the absence of adjuvant.

    PubMed

    Sedlik, C; Perraut, R; Bonnemains, B; Leclerc, C

    1996-01-01

    Although most strategies of vaccination require immunopotentiation to induce efficient immune responses, the development of new adjuvants for human vaccines is highly limited by safety problems. In order to overcome this problem, we developed a new vaccine formulation based on the covalent linkage of protein or peptide to synthetic microspheres. In previous experiments performed in mice, we demonstrated that these particulate antigens induce strong antigen-specific CD4+ T cell proliferative responses in the absence of adjuvant. In the present study, we analyzed the immunogenicity in primate Saimiri sciureus monkeys of two different proteins linked to synthetic microspheres. Immune responses induced by these particulate proteins administered without adjuvant were compared to those stimulated by the soluble antigens injected with alum. We currently demonstrated that, in monkeys, particulate antigens administered without adjuvant, induced good PBMC proliferative response and antibody production. Furthermore, the analysis of antibody responses using mAbs specific for different Saimiri sciureus immunoglobulins showed that the antibody response profiles were different in monkeys immunized with soluble versus particulate form of antigens. Results of this study demonstrate that particulate form of antigen may stimulate qualitatively different immune responses as compared to alum and therefore suggest that this new antigen formulation could be an attractive candidate for the development of vaccines. PMID:8852604

  6. Compensation of the Kerr effect for transient optomechanically induced transparency in a silica microsphere.

    PubMed

    Shen, Zhen; Dong, Chun-Hua; Chen, Yuan; Xiao, Yun-Feng; Sun, Fang-Wen; Guo, Guang-Can

    2016-03-15

    We have studied the Kerr effect in silica microspheres and demonstrated compensation of the Kerr effect for transient optomechanically induced transparency (OMIT). Due to the Kerr effect of the temporal strong driving pulse, an asymmetric transparency dip is observed during the transient OMIT experiment when the laser frequency is locked at one mechanical frequency, ω(m), below the whispering gallery mode resonance using a weak locking pulse. For compensation of the Kerr effect, we lock the laser at a lower frequency and show the symmetric transparency window. These results are important for studying photon-phonon interconversion, especially in systems with strong driving power. PMID:26977681

  7. Demonstration and characterization of distributed multiparticle-induced mode splitting in a microsphere resonator

    NASA Astrophysics Data System (ADS)

    Jin, Xueying; Dong, Yongchao; Wang, Keyi

    2016-03-01

    Recently introduced mode splitting (MS) in whispering gallery mode resonators (WGMRs) has been widely investigated as a highly sensitive sensing scheme. However, distributed multiparticle-induced MS has not been achieved experimentally up to date. Here, we demonstrate and characterize the multiparticle-induced MS where the sizes of detected particles are in a log-normal distribution using a microsphere resonator. We experimentally confirm that the total linewidth broadening is proportional to the number of adsorbed particles. The signal is immune to the angular positions of particles as well as the thermal fluctuations, which exhibits a more robust mechanism. Moreover, the proposed MS mechanism works equally well even under the unresolvable condition. Observation of mode splitting induced by distributed multiparticles provides a new way for concentration detection of nanoparticles in combustion, traffic exhaust and ambient atmosphere.

  8. [Drug-induced anomalous contraction of gastrointestinal tract of mice with impaired c-kit function].

    PubMed

    Tokutomi, Naofumi; Tokutomi, Yoshiko; Nishi, Katsuhide

    2004-03-01

    Drug-induced contraction of gastrointestinal tracts seems to depend upon the extent of their rhythmic contraction that is driven by the activity of gastrointestinal pacemaker cells. In BALB/c mice chronically administrated with a neutralizing anti-c-Kit monoclonal antibody (ACK2), rhythmic contraction of the gastrointestinal tract was impaired and contractile responses to drugs, including acetylcholine, prostaglandin F(2alpha), and bradykinin, were anomalously augmented. Histochemical analysis of the c-kit-positive cells in the gastrointestinal tract revealed the decreased number of c-kit-positive cells in the ACK2-treated animals, which lead to the impaired rhythmic contraction. Since the intestinal c-kit-positive cells in primary culture developed Ca(2+)-dependent rhythmic Cl(-) current, the rhythmic current is supposed to be an origin of gastrointestinal pacemakers. The extent of anomaly in drug-induced contraction correlated with the extent of impairment in rhythmic contraction. The drug-induced anomalous contraction in the preparation from ACK2-treated animals, which is accompanied by the impaired rhythmic contraction, was mimicked when the gastrointestinal segments from control animals were superfused with a low temperature organ bath solution at 25 degrees C. These results suggest that rhythmic discharge of excitation of smooth muscle cells, which is triggered by rhythmic excitatory input from c-kit cells, regulates the extent of drug-induced contraction. PMID:14993728

  9. Screening and identification of proteins mediating senna induced gastrointestinal motility enhancement in mouse colon

    PubMed Central

    Wang, Xin; Zhong, Yue-Xia; Lan, Mei; Zhang, Zong-You; Shi, Yong-Quan; Lu, Ju; Ding, Jie; Wu, Kai-Cun; Jin, Jian-Ping; Pan, Bo-Rong; Fan, Dai Min

    2002-01-01

    AIM: To isolate the proteins involved in pharmacologic action of senna extract (SE) from mouse gastrointestinal tract and to explore the molecular mechanism of gastrointestinal motility change induced by SE. METHODS: SE was administrated to mice by different routes. Gastrointestinal motility of mice was observed using cathartic, gastrointestinal propellant movement experiments and X-ray analysis. Mouse model for gastrointestinal motility enhancement was established through continuous gastric administration of SE at progressively increased dose. At 3 h and week 3, 4, 6 and 10, morphological changes of gastrointestinal tissues were found under light microscope. Ultrastructural changes of intestinal and colonic tissues at week 6 were observed under transmission electron microscope. The colonic proteomic changes in model mice were examined by two-dimension polyacrylamide gel electrophoresis with immobilized pH gradient isoelectric focusing to screen the differentially expressed proteins, and their molecular masses and isoelectric points were determined. Two N-terminal sequences of the samples were also determined by mass spectrometry. RESULTS: SE (0.3 g) caused diarrhea after gastric administration in 1-6 h and enhanced gastrointestinal propellant (65.1% ± 7.5%; 45.8% ± 14.6%,P < 0.01) in mice, but intramuscular and hypodermic injection had no cathartic effect. X-ray analysis of gastrointestinal motility demonstrated that gastric administration of SE enhanced gastric evacuation and gastrointestinal transferring function. At 3 h and week 3 and 4 after gastric administration of SE, light microscopic examination revealed no apparent change in gastrointestinal mucosal tissues, but transmission electron microscopic examination revealed inflammatory changes in whole layer of intestinal and colonic wall. Twenty differential proteins were detected in the colonic tissues of the model mice by two-dimensional electrophoresis, and the N-terminal amino acid sequences of two

  10. Effects of delayed treatment with nafronyl oxalate on microsphere embolism-induced changes in monoamine levels of rat brain regions.

    PubMed Central

    Takagi, N.; Miyake, K.; Ohiwa, A.; Nukaga, R.; Takeo, S.

    1996-01-01

    1. The present study was undertaken to examine the effects of delayed treatment with nafronyl oxalate (nafronyl), a cerebral vasodilator, on monoamine neurotransmitters of brain regions in the microsphere-embolized rat. 2. Microsphere embolism was induced by injecting 900 microspheres with a diameter of 48 microns into the right internal carotid artery of rats. Microsphere-embolized rats were treated with nafronyl, 15 mg kg-1, i.p., twice daily from the first to the 5th day. Levels of monoamines and their metabolites in the cerebral cortex, striatum, and hippocampus were measured on days 3 and 5 after the operation by a high-performance liquid chromatograph with electrochemical detection. In vivo tyrosine or tryptophan hydroxylation was estimated by measurement of the accumulation of 3, 4-dihydroxyphenylalanine or 5-hydroxy-1-tryptophan after administration of 3-hydroxybenzylhydrazine dihydrochloride, an inhibitor of aromatic L-amino acid decarboxylase. 3. Microsphere embolism induced decreases in dopamine, noradrenaline and 5-hydroxytryptamine in three brain regions of the right hemisphere on days 3 and 5. In the left hemisphere, the monoamines were reduced, but to a lesser degree than in the right hemisphere. On days 3 and 5, the decrease in the monoamines of the right hemisphere was attenuated by nafronyl treatment except for noradrenaline on day 3. The decrease in the monoamines levels in the left hemisphere was almost completely prevented by nafronyl treatment. 4. On day 3 after microsphere embolism, in vivo tyrosine and tryptophan hydroxylation was lower than the pre-embolic value in all three brain regions. Treatment of the embolized rats with nafronyl significantly attenuated the decrease in in vivo tyrosine and tryptophan hydroxylation in the ipsilateral hemisphere, but not hippocampal tryptophan hydroxylation. 5. The results suggested that treatment with nafronyl improves or attenuates changes in monoamine neurotransmitter metabolism of the brain regions

  11. Child and Parent Perceived Food-Induced Gastrointestinal Symptoms and Quality of Life in Children with Functional Gastrointestinal Disorders

    PubMed Central

    Carlson, Michelle J.; Moore, Carolyn E.; Tsai, Cynthia M.; Shulman, Robert J.; Chumpitazi, Bruno P.

    2014-01-01

    It is unknown whether children with functional gastrointestinal disorders (FGIDs) identify specific foods that exacerbate their gastrointestinal (GI) symptoms. The objectives of this study were to determine the perceived role of food on GI symptoms and to determine the impact of food-induced symptoms on quality of life (QOL) in children with FGIDs. Between August and November 2010, 25 children ages 11–17 years old with FGIDs and a parent completed a food symptom association questionnaire and validated questionnaires assessing FGID symptoms and QOL. In addition, children completed a 24-hour food recall, participated in focus groups to identify problematic foods and any coping strategies, and discussed how their QOL was affected. Statistical analyses were conducted using chi-squared, t-testing, Mann-Whitney U, Wilcoxon signed-rank, and Spearman’s rho. Children identified a median of 11 (range 2–25) foods as exacerbating a GI symptom, with the most commonly identified foods being spicy foods, cow’s milk, and pizza. Several coping strategies were identified including consuming smaller portions, modifying foods, and avoiding a median of 8 (range 1–20) foods. Children reported that food-induced symptoms interfered with school performance, sports, and social activities. Although the parent’s assessment of their child’s QOL negatively correlated with the number of perceived symptom-inducing foods in their child, this relationship was not found in the children. Findings suggest that specific foods are perceived to exacerbate GI symptoms in children with FGIDs. Moreover, despite use of several coping strategies, food-induced symptoms may adversely impact children’s QOL in several important areas. PMID:24360501

  12. Effects of naftidrofuryl oxalate on microsphere embolism-induced decrease in regional blood flow of rat brain.

    PubMed Central

    Miyake, K.; Takagi, N.; Takeo, S.

    1994-01-01

    1. The purpose of the present study was to determine whether naftidrofuryl oxalate (naftidrofuryl), a vasodilator, is capable of improving brain regional blood flow of animals in sustained ischaemia. 2. Cerebral ischaemia was induced by injecting 900 microspheres (48 microns in diameter) into the right internal carotid artery of rats. Cerebral blood flow of brain regions was measured by a hydrogen clearance method on the 3rd, 7th and 28th days after the onset of ischaemia. Ischaemic animals were treated with naftidrofuryl, 15 mg kg-1 day-1 i.p., from the first to 28th day. 3. Microsphere-embolism caused a sustained decrease in cortical and striatal blood flow over a period of 28 days, whereas hippocampal blood flow was decreased on the 3rd day but not on the 7th or 28th day. On the 3rd day, the striatal and hippocampal but not cortical blood flow of naftidrofuryl-treated, microsphere-embolized rats was higher than untreated rats. On the 7th and 28th days, the cortical and striatal blood flow of the treated and untreated animals did not differ. 4. Brain slices from microsphere-embolized rats contained areas, which were not stained with triphenyltetrazolium chloride (TTC), to a similar degree on the 3rd, 7th and 28th days, indicating the genesis of cerebral infarction. TTC-unstained areas of microsphere-embolized rats that had received naftidrofuryl treatment were smaller than those of untreated rats on the 3rd and 7th days, but not on the 28th day.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8032646

  13. Gastrointestinal Hormones and Bariatric Surgery-induced Weight Loss

    PubMed Central

    Ionut, Viorica; Burch, Miguel; Youdim, Adrienne; Bergman, Richard N.

    2015-01-01

    Obesity continues to be a major public health problem in the United States and worldwide. While recent statistics have demonstrated that obesity rates have begun to plateau, more severe classes of obesity are accelerating at a faster pace with important implications in regards to treatment. Bariatric surgery has a profound and durable effect on weight loss, being to date one of the most successful interventions for obesity. Objective To provide updates to the possible role of gut hormones in post bariatric surgery weight loss and weight loss maintenance. Design and Methods The current review examines the changes in gastro-intestinal hormones with bariatric surgery and the potential mechanisms by which these changes could result in decreased weight and adiposity. Results The mechanism by which bariatric surgery results in body weight changes is incompletely elucidated, but it clearly goes beyond caloric restriction and malabsorption. Conclusion Changes in gastro-intestinal hormones, including increases in GLP-1, PYY, and oxyntomodulin, decreases in GIP and ghrelin, or the combined action of all these hormones might play a role in induction and long-term maintenance of weight loss. PMID:23512841

  14. Synthesis of nanofibrous gelatin/silica bioglass composite microspheres using emulsion coupled with thermally induced phase separation.

    PubMed

    Noh, Da-Young; An, Young-Hyeon; Jo, In-Hwan; Koh, Young-Hag; Kim, Hyoun-Ee

    2016-05-01

    This study proposes an innovative way of synthesizing porous gelatin/silica bioglass composite microspheres with a nanofibrous structure using emulsion coupled with thermally induced phase separation (TIPS). In particular, a mixture of the solvent (water) and non-solvent (ethanol) was used to induce a unique phase separation of gelatin/silica mixtures (i.e. gelatin/silica hybrid-rich and liquid-rich phases) at -70 °C for the creation of a nanofibrous structure. All the composite microspheres synthesized with silica contents of 10 wt.%, 15 wt.%, and 20 wt.% had well-defined spherical shapes between 124 and 136 μm in size. In addition, they were comprised of nanofibrous gelatin/silica composite walls (several tens of nanometers in thickness), where the sol-gel derived silica bioglass phase was uniformly distributed throughout the gelatin matrix. The in vitro apatite-forming ability and biocompatibility of the nanofibrous gelatin/silica bioglass composite microspheres was significantly enhanced with an increase in silica content, demonstrating their great potential for the promotion of bone tissue regeneration. PMID:26952472

  15. Coupling Light from a High-Q Microsphere Resonator Using a UV-induced Surface Grating

    NASA Technical Reports Server (NTRS)

    Ilchenko, V. S.; Starodubov, D. S.; Gorodetsky, M. L.; Maleki, L.; Feinberg, J.

    2000-01-01

    High-Q microspheres with whispering-gallery modes have very narrow resonances that can be used for fiber-optic filters, ultra-compact narrow-linewidth lasers and optical/microwave oscillators. Whispering-gallery modes were previously excited in microspheres using evanescent optical fields. The necessary phase synchronism was obtained by adjusting the incident angle of input light beam (prism coupler) or adjustment of the waveguide propagation constant (fiber taper coupler). For many applications, however, bulky near-field couplers are undesirable. They compromise the symmetry and generate stray fields. Also, the control of coupling is crucial for the performance of microsphere resonators: in analogy with radio frequency circuits, the loading Q-factor should be less than the intrinsic Q-factor, Q(sub L) less than or equal to Q(sub O). Ideally one should combine a stable coupling element and a resonator into a single microsphere component.

  16. An erythromycin derivative, EM-523, induces motilin-like gastrointestinal motility in dogs.

    PubMed

    Inatomi, N; Satoh, H; Maki, Y; Hashimoto, N; Itoh, Z; Omura, S

    1989-11-01

    The effect of an erythromycin derivative, EM-523, on gastrointestinal motility was investigated in conscious dogs and compared with that of motilin cisapride, trimebutine and metoclopramide. In the fasting state, EM-523 given i.v. or i.d. at 3 micrograms/kg or more induced contractions in the stomach that migrated along the small intestine. The pattern of the contractions was very similar to that induced by motilin. In the digestive state, EM-523 increased the amplitude of gastric contractions. Cisapride and metoclopramide increased gastrointestinal motility both in the fasting and digestive states; however, their contractile pattern was different from that of EM-523. Trimebutine did not induce gastric motility in the fasting state but rather decreased gastric motility in the digestive state. The contractions induced by EM-523 and motilin were inhibited by atropine but were not affected by naloxone, suggesting that the cholinergic pathway is important in the exertion of their action. These results indicate that EM-523 mimics motilin in stimulating gastrointestinal motility and that this agent may be useful treat gastrointestinal disorders such as gastric stasis, gastroesophageal reflux, and postoperative ileus, and so forth. PMID:2810120

  17. Polycation-decorated PLA microspheres induce robust immune responses via commonly used parenteral administration routes.

    PubMed

    Chen, Xiaoming; Wang, Lianyan; Liu, Qi; Jia, Jilei; Liu, Yuan; Zhang, Weifeng; Ma, Guanghui; Su, Zhiguo

    2014-12-01

    Recombinant viral subunit-based vaccines have gained increasing attention due to their enhanced safety over the classic live-attenuated or inactivated vaccines. The low immunogenicity of the subunit antigen alone, however, requires the addition of an adjuvant to induce immunity. Particulate-based delivery systems have great potential for developing new vaccine adjuvants, compared to traditional aluminum-based saline adjuvants. The physicochemical properties of particulate vaccines have been extensively investigated; however, few studies have focused on how the administration route of various adjuvant-antigen combinations impacts the efficacy of the immune response. Here, for the first time, the viral Hepatitis B surface antigen (HBsAg) was combined with aluminum-based or cationic-microsphere (MP) based adjuvants to investigate the characteristics of immune responses elicited after immunization via the subcutaneous, intramuscular, or intraperitoneal routes respectively. In vitro, the MP-based vaccine significantly increased dendritic cell (DC) activation with up-regulated CD40 and CD80 expression and IL-12 production compared to alum-based vaccine. After immunization, both MP and alum-based vaccines produced increased IgG titers in mice. The administration route of these vaccines did influenced immune responses. The MP-based vaccine delivered via the intramuscular route yielded the highest levels of the IgG2a isotype. The alum-based vaccine, delivered via the same route, produced an IgG1-dominated humoral immune response. Moreover, subcutaneous and intramuscular immunizations with MP-based vaccine augmented Granzyme B, Th1-type cytokines (IL-2, IL-12, and IFN-γ), and Th2 cytokine IL-4 secretions. These results demonstrate that MP-based vaccines have the capacity to induce higher cellular and humoral immune response especially via an intramuscular administration route than an alum-based vaccine. PMID:25466267

  18. Child and parent perceived food-induced gastrointestinal symptoms and quality of life in children with functional gastrointestinal disorders.

    PubMed

    Carlson, Michelle J; Moore, Carolyn E; Tsai, Cynthia M; Shulman, Robert J; Chumpitazi, Bruno P

    2014-03-01

    It is unknown whether children with functional gastrointestinal (GI) disorders identify specific foods that exacerbate their GI symptoms. The objectives of this study were to determine the perceived role of food on GI symptoms and to determine the impact of food-induced symptoms on quality of life (QOL) in children with functional GI disorders. Between August and November 2010, 25 children ages 11 to 17 years old with functional GI disorders and a parent completed a food symptom association questionnaire and validated questionnaires assessing FGID symptoms and QOL. In addition, children completed a 24-hour food recall, participated in focus groups to identify problematic foods and any coping strategies, and discussed how their QOL was affected. Statistical analyses were conducted using χ2, t test, Mann-Whitney U test, Wilcoxon signed rank, and Spearman's ρ. Children identified a median of 11 (range=2 to 25) foods as exacerbating a GI symptom, with the most commonly identified foods being spicy foods, cow's milk, and pizza. Several coping strategies were identified, including consuming smaller portions, modifying foods, and avoiding a median of 8 (range=1 to 20) foods. Children reported that food-induced symptoms interfered with school performance, sports, and social activities. Although the parent's assessment of their child's QOL negatively correlated with the number of perceived symptom-inducing foods in their child, this relationship was not found in the children. Findings suggest that specific foods are perceived to exacerbate GI symptoms in children with functional GI disorders. In addition, despite use of several coping strategies, food-induced symptoms can adversely impact children's QOL in several important areas. PMID:24360501

  19. Neuroprotective Effects of Engineered Polymeric Nasal Microspheres Containing Hydroxypropyl-β-cyclodextrin on β-Amyloid (1-42)-Induced Toxicity.

    PubMed

    Yalcin, Ayfer; Soddu, Elena; Turunc Bayrakdar, Ezgi; Uyanikgil, Yigit; Kanit, Lutfiye; Armagan, Guliz; Rassu, Giovanna; Gavini, Elisabetta; Giunchedi, Paolo

    2016-08-01

    β-Amyloid (Aβ) plaques are the key neurotoxic assemblies in Alzheimer disease. It has been suggested that an interaction occurs between membrane cholesterol and Aβ aggregation in the brain. Cyclodextrins can remove cholesterol from cell membranes and change receptor function. This study aimed to investigate the effect of hydroxypropyl-β-cyclodextrin (HP-CD) polymeric microspheres, based on chitosan or sodium alginate, on the levels of lipid peroxidation, reactive oxygen species production, and mitochondrial function in brain synaptosomes. The effect of microspheres on DNA fragmentation, the expression of Bcl-2, Bax, and Apex1 mRNAs in rat hippocampus after Aβ(1-42) peptide-induced neurotoxicity was also evaluated. Comparison with HP-CD raw material was performed. Aβ(1-42) treatment significantly decreased the mitochondrial activity of Apex1 and Bcl-2 mRNAs, induced DNA fragmentation, and increased mRNA levels of Bax. Treatment with HP-CD microspheres against Aβ(1-42) significantly reduced DNA fragmentation and increased the Bcl-2/Bax mRNA ratio and mitochondrial function. In addition, HP-CD microspheres used against Aβ(1-42) decreased the levels of lipid peroxidation and reactive oxygen species production. These results indicate that nasally administered spray-dried HP-CD microspheres are able to provide protection against Aβ(1-42)-induced neurotoxicity, due to the suppressed levels of oxidative stress and apoptotic signals in the rat hippocampus. PMID:27353207

  20. External compression-induced fracture patterning on the surface of poly(dimethylsiloxane) cubes and microspheres

    PubMed Central

    Uchida, Tomoyuki; Mills, K.L.; Kuo, Chuan-Hsien; Roh, Whijae; Tung, Yi-Chung; Garner, Amanda L.; Koide, Kazunori; Thouless, M.D.; Takayama, Shuichi

    2009-01-01

    This paper describes a method for creating sub-micron surface patterns on cubes and microspheres. In this method, PDMS cubes and microspheres are exposed to oxygen plasma, which creates a very thin, hard, surface-modified layer on a compliant substrate. These are then compressed, causing the layer to crack in patterns dictated by the distribution of tensile stresses in the surface layer. Cracks with sub-micron widths were generated on 1 cm3 cubes and 800 µm-diameter microspheres, and the resulting crack patterns were observed. Finite-element simulations of the tensile stress distributions reveal that the fracture patterns arise from different mechanisms in the cubes and spheres. In particular, pattern formation is associated with frictional contact in the cubes; but not in the microspheres where geometrical effects associated with changes in the cross-sectional area along the axis lead to generation of tensile stress. These observations and analyses provide a foundation on which to predict and guide crack pattern formation on a wide variety of small 3D objects. In anticipation of future applications in materials science and biology, we demonstrate selective deposition of compounds into the cracks to make them functionally differentiable from the rest of the surface. PMID:19437776

  1. Manifestations of food protein induced gastrointestinal allergies presenting to a single tertiary paediatric gastroenterology unit

    PubMed Central

    2013-01-01

    Background Food protein induced gastrointestinal allergies are difficult to characterise due to the delayed nature of this allergy and absence of simple diagnostic tests. Diagnosis is based on an allergy focused history which can be challenging and often yields ambiguous results. We therefore set out to describe a group of children with this delayed type allergy, to provide an overview on typical profile, symptoms and management strategies. Methods This retrospective analysis was performed at Great Ormond Street Children’s Hospital. Medical notes were included from 2002 – 2009 where a documented medical diagnosis of food protein induced gastrointestinal allergies was confirmed by an elimination diet with resolution of symptoms, followed by reintroduction with reoccurrence of symptoms. Age of onset of symptoms, diagnosis, current elimination diets and food elimination at time of diagnosis and co-morbidities were collected and parents were phoned again at the time of data collection to ascertain current allergy status. Results Data from 437 children were analysis. The majority (67.7%) of children had an atopic family history and 41.5% had atopic dermatitis at an early age. The most common diagnosis included, non-IgE mediated gastrointestinal food allergy (n = 189) and allergic enterocolitis (n = 154) with symptoms of: vomiting (57.8%), back-arching and screaming (50%), constipation (44.6%), diarrhoea (81%), abdominal pain (89.9%), abdominal bloating (73.9%) and rectal bleeding (38.5%). The majority of patients were initially managed with a milk, soy, egg and wheat free diet (41.7%). At a median age of 8 years, 24.7% of children still required to eliminate some of the food allergens. Conclusions This large retrospective study on children with food induced gastrointestinal allergies highlights the variety of symptoms and treatment modalities used in these children. However, further prospective studies are required in this area of food allergy. PMID:23919257

  2. Micro-sphere model for strain-induced crystallisation and three-dimensional applications

    NASA Astrophysics Data System (ADS)

    Guilié, J.; Le, Thien-Nga; Le Tallec, P.

    2015-08-01

    Strain-crystallising rubber exhibits interesting properties: for instance, fatigue lifetime is known to be modified by this microstructural evolution which dissipates energy and creates a strong anisotropic reinforcement. We develop herein a micro-sphere 3D constitutive model for such strain-crystallising rubber. It is based on a simplified 1D micromechanical model that we extend with a micro-sphere approach to a full thermodynamically consistent evolutive anisotropic model. A specific numerical strategy is then proposed. The model is assessed on several significative configurations and reproduces the main experimental features while predicting the evolution of anisotropy as a function of the loading history. We finally show that it can also predict the crystallised zone in front of a mode I crack.

  3. High-precision measurements of light-induced torque on absorbing microspheres

    NASA Astrophysics Data System (ADS)

    Capitanio, Marco; Normanno, Davide; Saverio Pavone, Francesco

    2004-10-01

    Laser beams have been demonstrated to be capable of exerting torque as well as forces on microparticles. Using a custom magneto-optic manipulator, we directly measured the torque exerted by laser light on absorbing microspheres as a result of the transfer of spin angular momentum. A general method for measuring torque has been developed, and the experimental apparatus has shown a sensitivity of ~1 pN/nm.

  4. Can food protein induced enterocolitis syndrome shift to immediate gastrointestinal hypersensitivity? A report of two cases.

    PubMed

    Onesimo, R; Dello Iacono, I; Giorgio, V; Limongelli, M G; Miceli Sopo, S

    2011-03-01

    Food protein induced enterocolitis syndrome (FPIES) is a food-related non-IgE-mediated gastrointestinal hypersensitivity disorder. Atypical FPIES is characterized by the presence of specific IgE for the causative food. The guidelines suggested for diagnostic oral food challenge in pediatric patients affected by suspected FPIES are different from the ones for children with IgE-mediated food allergy. We describe two cases of atypical FPIES that turned into IgE-mediated gastrointestinal anaphylaxis. Our experience suggests to adapt OFC according to the outcome of specific IgE for the causative food When causative food-related IgE werepositive, we suggest to follow the guidelines for IgE mediated food allergy. PMID:21608375

  5. Selenium Deficiency-Induced Inflammation and Increased Expression of Regulating Inflammatory Cytokines in the Chicken Gastrointestinal Tract.

    PubMed

    Gao, Xuejiao; Zhang, Ziwei; Xing, Houjuan; Yu, Jiao; Zhang, Naisheng; Xu, Shiwen

    2016-09-01

    Selenium (Se), a nutritionally essential trace element, plays an important role in various aspects of health for a wide range of species, including birds. Se deficiency inhibits the growth of immune organs and decreases immune function, leading to many inflammatory diseases. The present study determined the effects and mechanism of dietary Se deficiency on gastrointestinal tract tissue inflammation. The histopathological changes showed that Se deficiency induced inflammatory lesions in the gastrointestinal tract tissues (glandular stomach, gizzard, duodenum, small intestine, and rectum). The expression levels of PTGE (prostagland E synthase), COX-2 (cyclooxygenase-2), TNF-α (tumor necrosis factor α), and NF-κB (nuclear transfer factor κB) in the gastrointestinal tract tissues (glandular stomach, gizzard, duodenum, small intestine, and rectum) were determined by qPCR on days 15, 25, 35, 45, and 55, respectively. The results showed that Se deficiency induced high expression levels of PTGE, COX-2, TNF-α, and NF-κB in the gastrointestinal tract tissues. The effects were more obvious in the duodenum and small intestine than those in the glandular stomach, gizzard, and rectum. In addition, the expression levels of these proteins in the gastrointestinal tract tissue increased in a time-dependent manner with Se deficiency feeding time. Furthermore, Se deficiency induced the production of pro-inflammatory factors, thus aggravating inflammatory lesions in the gastrointestinal tract. The effect of Se deficiency on inflammation and other gastrointestinal tract diseases should be further studied. PMID:26899319

  6. Melatonin Attenuates Noise Stress-induced Gastrointestinal Motility Disorder and Gastric Stress Ulcer: Role of Gastrointestinal Hormones and Oxidative Stress in Rats

    PubMed Central

    Zhang, Lei; Gong, Ji T; Zhang, Hu Q; Song, Quan H; Xu, Guang H; Cai, Lei; Tang, Xiao D; Zhang, Hai F; Liu, Fang-E; Jia, Zhan S; Zhang, Hong W

    2015-01-01

    Background/Aims There are increasing evidences for gastrointestinal motility disorder (GIMD) and gastric stress ulcer induced by noise stress. The present study was to investigate the reversed effect of melatonin on GIMD and gastric stress ulcer induced by noise stress and potential mechanism. Methods Noise stress was induced on rats, and melatonin (15 mg/kg) was administered to rats by intraperitoneal injection. Differences were assessed in gastric residual rate (GRR), small intestine propulsion rate (SPR), Guth injury score, cortisol, gastrointestinal hormones (calcitonin-gene-related peptide and motilin) and oxidative stress markers (superoxide dismutase and malondialde hyde) in blood plasma as well as gastric mucosa homogenate with or without melatonin. The pathological examination of gastric mucosa was also performed. Results The GRR and SPR were improved by noise stress compared with control (P < 0.05). The pathological examination and Guth injury score revealed gastric stress ulcer. Moreover, the levels of cortisol, motilin and malondialdehyde in blood plasma and malondialdehyde in gastric mucosa homogenate were increased by noise stress (P < 0.05). CGRP and superoxide dismutase activity in both of blood plasma and gastric mucosa homogenate were significantly decreased (P< 0.05). Furthermore, melatonin reversed changes in GRR, SPR, pathological examination, Guth injury score, cortisol, motilin, CGRP, superoxide dismutase activity and malondialdehyde (P < 0.05). Conclusions Melatonin is effective in reversing the GIMD and gastric stress ulcer induced by noise stress. The underlying mechanism may be involved in oxidative stress and gastrointestinal hormones. PMID:25537679

  7. Polyacrolein microspheres

    NASA Technical Reports Server (NTRS)

    Rembaum, Alan (Inventor)

    1986-01-01

    Microspheres of acrolein homopolymers and copolymer with hydrophillic comonomers such as methacrylic acid and/or hydroxyethylmethacrylate are prepared by cobalt gamma irradiation of dilute aqueous solutions of the monomers in presence of suspending agents, especially alkyl sulfates such as sodium dodecyl sulfate. Amine or hydroxyl modification is achieved by forming adducts with diamines or alkanol amines. Carboxyl modification is effected by oxidation with peroxides. Pharmaceuticals or other aldehyde reactive materials can be coupled to the microspheres. The microspheres directly form antibody adducts without agglomeration.

  8. Polyacrolein microspheres

    NASA Technical Reports Server (NTRS)

    Rembaum, Alan (Inventor)

    1983-01-01

    Microspheres of acrolein homopolymers and co-polymer with hydrophillic comonomers such as methacrylic acid and/or hydroxyethylmethacrylate are prepared by cobalt gamma irradiation of dilute aqueous solutions of the monomers in presence of suspending agents, especially alkyl sulfates such as sodium dodecyl sulfate. Amine or hydroxyl modification is achieved by forming adducts with diamines or alkanol amines. Carboxyl modification is effected by oxidation with peroxides. Pharmaceuticals or other aldehyde reactive materials can be coupled to the microspheres. The microspheres directly form antibody adducts without agglomeration.

  9. Polyacrolein microspheres

    NASA Technical Reports Server (NTRS)

    Rembaum, Alan (Inventor)

    1987-01-01

    Microspheres of acrolein homopolymers and copolymer with hydrophillic comonomers such as methacrylic acid and/or hydroxyethylmethacrylate are prepared by cobalt gamma irradiation of dilute aqueous solutions of the monomers in presence of suspending agents, especially alkyl sulfates such as sodium dodecyl sulfate. Amine or hydroxyl modification is achieved by forming adducts with diamines or alkanol amines. Carboxyl modification is effected by oxidation with peroxides. Pharmaceuticals or other aldehyde reactive materials can be coupled to the microspheres. The microspheres directly form antibody adducts without agglomeration.

  10. Initial Metabolic State and Exercise-Induced Endotoxaemia Are Unrelated to Gastrointestinal Symptoms During Exercise

    PubMed Central

    Moncada-Jimènez, José; Plaisance, Eric P.; Mestek, Michael L.; Araya-Ramirez, Felipe; Ratcliff, Lance; Taylor, James K.; Grandjean, Peter W.; Aragonvargas, Luis F.

    2009-01-01

    The aim of the study was to investigate the association between the initial metabolic state and exercise-induced endotoxaemia on the appearance of gastrointestinal symptoms (GIS) during exercise. Eleven males (36.6 ± 4.9 yrs, 1.7 ± 0.1 m, 74.5 ± 7.7 kg, DEXA body fat % 17.2 ± 6.6, VO2max 57.4 ± 7.4 ml·kg-1·min-1) underwent two isoenergetic diets designed to change their initial metabolic status by either depleting or maintaining their hepatic and muscular glycogen content. These diets and accompanying exercise sessions were performed by each participant in the days before completing a laboratory-based duathlon (5-km run, 30-km cycling, 10-km run). Blood samples were obtained before, immediately and 1- and 2-h following the duathlon for determination of insulin (IN), glucagon (GL), endotoxin, aspartic aminotransferase (AST), and alanine aminotransferase (ALT) markers. GIS were assessed by survey before and after exercise. Diet content produced a different energy status as determined by macronutrient content and the IN/GL ratio (p < 0.05), and mild exercise-induced endotoxaemia was observed in both experimental duathlons. Regardless of the diet, the AST/ALT ratio following exercise and in the recovery phase indicated hepatocyte and liver parenchyma structural damage. In spite of GIS, no significant correlations between endotoxin levels and GIS were found. In conclusion, increased markers of endotoxaemia observed with the high-intensity exercise were unrelated to hepatic function and/or GIS before and after exercise. Key points Gastrointestinal symptoms before, during, and after a competition are reported by approximately 20%-50% of the athletes participating in endurance events such as marathon, cycling and triathlon. Energy status, exercise-induced endotoxaemia and liver structural damage might be related to gastrointestinal symptoms. In this study, gastrointestinal symptoms observed before and after endurance exercise were unrelated to endotoxin levels or

  11. Molecular cloning of motilin and mechanism of motilin-induced gastrointestinal motility in Japanese quail.

    PubMed

    Apu, Auvijit Saha; Mondal, Anupom; Kitazawa, Takio; Takemi, Shota; Sakai, Takafumi; Sakata, Ichiro

    2016-07-01

    Motilin, a peptide hormone produced in the upper intestinal mucosa, plays an important role in the regulation of gastrointestinal (GI) motility. In the present study, we first determined the cDNA and amino acid sequences of motilin in the Japanese quail and studied the distribution of motilin-producing cells in the gastrointestinal tract. We also examined the motilin-induced contractile properties of quail GI tracts using an in vitro organ bath, and then elucidated the mechanisms of motilin-induced contraction in the proventriculus and duodenum of the quail. Mature quail motilin was composed of 22 amino acid residues, which showed high homology with chicken (95.4%), human (72.7%), and dog (72.7%) motilin. Immunohistochemical analysis showed that motilin-immunopositive cells were present in the mucosal layer of the duodenum (23.4±4.6cells/mm(2)), jejunum (15.2±0.8cells/mm(2)), and ileum (2.5±0.7cells/mm(2)), but were not observed in the crop, proventriculus, and colon. In the organ bath study, chicken motilin induced dose-dependent contraction in the proventriculus and small intestine. On the other hand, chicken ghrelin had no effect on contraction in the GI tract. Motilin-induced contraction in the duodenum was not inhibited by atropine, hexamethonium, ritanserin, ondansetron, or tetrodotoxin. However, motilin-induced contractions in the proventriculus were significantly inhibited by atropine and tetrodotoxin. These results suggest that motilin is the major stimulant of GI contraction in quail, as it is in mammals and the site of action of motilin is different between small intestine and proventriculus. PMID:27179882

  12. Amelioration of radiation-induced hematopoietic and gastrointestinal damage by Ex-RAD® in mice

    PubMed Central

    Ghosh, Sanchita P.; Kulkarni, Shilpa; Perkins, Michael W.; Hieber, Kevin; Pessu, Roli L.; Gambles, Kristen; Maniar, Manoj; Kao, Tzu-Cheg; Seed, Thomas M.; Kumar, K. Sree

    2012-01-01

    The aim of the present study was to assess recovery from hematopoietic and gastrointestinal damage by Ex-RAD®, also known as ON01210.Na (4-carboxystyryl-4-chlorobenzylsulfone, sodium salt), after total body radiation. In our previous study, we reported that Ex-RAD, a small-molecule radioprotectant, enhances survival of mice exposed to gamma radiation, and prevents radiation-induced apoptosis as measured by the inhibition of radiation-induced protein 53 (p53) expression in cultured cells. We have expanded this study to determine best effective dose, dose-reduction factor (DRF), hematological and gastrointestinal protection, and in vivo inhibition of p53 signaling. A total of 500 mg/kg of Ex-RAD administered at 24 h and 15 min before radiation resulted in a DRF of 1.16. Ex-RAD ameliorated radiation-induced hematopoietic damage as monitored by the accelerated recovery of peripheral blood cells, and protection of granulocyte macrophage colony-forming units (GM-CFU) in bone marrow. Western blot analysis on spleen indicated that Ex-RAD treatment inhibited p53 phosphorylation. Ex-RAD treatment reduces terminal deoxynucleotidyl transferase mediated dUTP nick end labeling assay (TUNEL)-positive cells in jejunum compared with vehicle-treated mice after radiation injury. Finally, Ex-RAD preserved intestinal crypt cells compared with the vehicle control at 13 and 14 Gy. The results demonstrated that Ex-RAD ameliorates radiation-induced peripheral blood cell depletion, promotes bone marrow recovery, reduces p53 signaling in spleen and protects intestine from radiation injury. PMID:22843617

  13. Sodium selenosulfate at an innocuous dose markedly prevents cisplatin-induced gastrointestinal toxicity

    SciTech Connect

    Li, Jun; Sun, Kang; Ni, Lijuan; Wang, Xufang; Wang, Dongxu; Zhang, Jinsong

    2012-02-01

    Our previous studies in mice revealed that two weeks short-term toxicity of sodium selenosulfate was significantly lower than that of sodium selenite, but selenium repletion efficacy of both compounds was equivalent. In addition, we showed that sodium selenosulfate reduced nephrotoxicity of cisplatin (CDDP) without compromising its anticancer activity, thus leading to a dramatic increase of cancer cure rate from 25% to 75%. Hydration has been used in clinical practice to reduce CDDP-induced nephrotoxicity, but it cannot mitigate CDDP-induced gastrointestinal toxicity. The present work investigated whether sodium selenosulfate is a potential preventive agent for the gastrointestinal toxicity. In tumor-bearing mice, sodium selenosulfate was administered at a dose of 9.5 μmol/kg daily for 11 days, CDDP alone resulted in diarrhea by 88% on day 12, whereas the co-administration of CDDP and sodium selenosulfate dramatically reduced diarrhea to 6% (p < 0.0001). Such a prominent protective effect promoted us to evaluate the safety potential of long-term sodium selenosulfate application. Mice were administered with sodium selenosulfate or sodium selenite for 55 days at the doses of 12.7 and 19 μmol/kg. The low-dose sodium selenite caused growth suppression and hepatotoxicity which were aggravated by the high-dose, leading to 40% mortality rate, but no toxic symptoms were observed in the two sodium selenosulfate groups. Altogether these results clearly show that sodium selenosulfate at an innocuous dose can markedly prevent CDDP-induced gastrointestinal toxicity. -- Highlights: ►Cisplatin resulted in diarrhea in mice by 88%. ►i.p. selenosulfate at 9.5 μmol/kg daily for 11 days reduced diarrhea to 6%. ►i.p. selenosulfate at 19 μmol/kg daily for 55 days was not toxic. ►i.p. selenite at 19 μmol/kg daily for 55 days was lethal. ►Innocuous dose of selenosulfate greatly prevents cisplatin-induced diarrhea.

  14. Ginger for Prevention of Antituberculosis-induced Gastrointestinal Adverse Reactions Including Hepatotoxicity: A Randomized Pilot Clinical Trial.

    PubMed

    Emrani, Zahra; Shojaei, Esphandiar; Khalili, Hossein

    2016-06-01

    In this study, the potential benefits of ginger in preventing antituberculosis drug-induced gastrointestinal adverse reactions including hepatotoxicity have been evaluated in patients with tuberculosis. Patients in the ginger and placebo groups (30 patients in each group) received either 500 mg ginger (Zintoma)(®) or placebo one-half hour before each daily dose of antituberculosis drugs for 4 weeks. Patients' gastrointestinal complaints (nausea, vomiting, dyspepsia, and abdominal pain) and antituberculosis drug-induced hepatotoxicity were recorded during the study period. In this cohort, nausea was the most common antituberculosis drug-induced gastrointestinal adverse reactions. Forty eight (80%) patients experienced nausea. Nausea was more common in the placebo than the ginger group [27 (90%) vs 21 (70%), respectively, p = 0.05]. During the study period, 16 (26.7%) patients experienced antituberculosis drug-induced hepatotoxicity. Patients in the ginger group experienced less, but not statistically significant, antituberculosis drug-induced hepatotoxicity than the placebo group (16.7% vs 36.7%, respectively, p = 0.07). In conclusion, ginger may be a potential option for prevention of antituberculosis drug-induced gastrointestinal adverse reactions including hepatotoxicity. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26948519

  15. Gastrointestinal blood loss induced by three different non-steroidal anti-inflammatory drugs.

    PubMed

    Bidlingmaier, A; Hammermaier, A; Nagyiványi, P; Pabst, G; Waitzinger, J

    1995-04-01

    A clinical study was performed on 18 healthy volunteers to compare the gastrointestinal daily blood loss induced by oral intake of three different non-steroidal anti-inflammatory drugs, lysine clonixinate (CAS 55837-30-4), ibuprofen (CAS 15687-27-1) and acetylsalicylic acid (CAS 50-78-2 ASA). For quantitative determination of gastrointestinal blood loss, autologous erythrocytes were radiolabelled in vitro with 51Cr and reinfused at study start. The amount of radioactivity excreted in faeces was measured during a placebo baseline phase of three days, a treatment phase of five days with thrice daily dosing of ASA, ibuprofen or lysine clonixinate and a subsequent wash-out phase of five days. The highest increase of mean daily blood loss over baseline was observed after treatment with ASA (+ 1.66 ml/d versus baseline). Treatment with ibuprofen led to an increase of mean daily blood loss by + 0.52 ml/d. During treatment with lysine clonixinate the mean increase of daily blood loss was +0.32 ml/d versus baseline. In the ibuprofen and lysine clonixinate treatment groups the values of mean daily blood loss decreased during the wash-out phase with respect to the verum phase, whereas the mean daily blood loss during the wash-out phase after treatment with ASA even increased in comparison to the verum phase (mean daily blood loss: +2.07 ml/d versus baseline. PMID:7779148

  16. Acute Pancreatitis and Gastroduodenal Intussusception Induced by an Underlying Gastric Gastrointestinal Stromal Tumor: A Case Report

    PubMed Central

    Doğan, Ahmet; Koparan, Ibrahim Halil; Adin, Mehmet Emin

    2016-01-01

    Gastrointestinal stromal tumors (GISTs) are rare tumors of the gastrointestinal system and comprise only 1% to 3% of all gastrointestinal tract tumors, with the majority of them arising in the stomach. In this report, we present the unique findings of a case of gastroduodenal intussusception caused by an underlying gastric GIST and complicated with severe acute pancreatitis. PMID:27104028

  17. Blackberry subjected to in vitro gastrointestinal digestion affords protection against Ethyl Carbamate-induced cytotoxicity.

    PubMed

    Chen, Wei; Xu, Yang; Zhang, Lingxia; Su, Hongming; Zheng, Xiaodong

    2016-12-01

    Ethyl Carbamate (EC) was detected in many fermented foods. Previous studies indicated that frequent exposure to ethyl carbamate may increase the risk to suffer from cancers. Blackberry is rich in polyphenols and possesses potent antioxidant activity. This study aims to investigate the protective effect of blackberry homogenates produced before (BH) and after in vitro simulated gastrointestinal digestion (BD) on EC-induced toxicity in Caco-2 cells. Our results showed that blackberry homogenates after digestion (BD) was more effective than that before digestion (BH) in ameliorating EC-induced toxicity in Caco-2 cells. Further investigation revealed that BD remarkably attenuated EC-induced toxicity through restoring mitochondrial function, inhibiting glutathione depletion and decreasing overproduction of intracellular reactive oxygen species. Additionally, LC-MS result implied that the better protective capacity of BD may be related to the increased content of two anthocyanins (cyanidin-3-glucoside and cyanidin-3-dioxalyglucoside). Overall, the present study may give implication to prevent EC-induced health problem. PMID:27374576

  18. Carboplatin/taxane-induced gastrointestinal toxicity: a pharmacogenomics study on the SCOTROC1 trial.

    PubMed

    He, Y J; Winham, S J; Hoskins, J M; Glass, S; Paul, J; Brown, R; Motsinger-Reif, A; McLeod, H L

    2016-06-01

    Carboplatin/taxane combination is first-line therapy for ovarian cancer. However, patients can encounter treatment delays, impaired quality of life, even death because of chemotherapy-induced gastrointestinal (GI) toxicity. A candidate gene study was conducted to assess potential association of genetic variants with GI toxicity in 808 patients who received carboplatin/taxane in the Scottish Randomized Trial in Ovarian Cancer 1 (SCOTROC1). Patients were randomized into discovery and validation cohorts consisting of 404 patients each. Clinical covariates and genetic variants associated with grade III/IV GI toxicity in discovery cohort were evaluated in replication cohort. Chemotherapy-induced GI toxicity was significantly associated with seven single-nucleotide polymorphisms in the ATP7B, GSR, VEGFA and SCN10A genes. Patients with risk genotypes were at 1.53 to 18.01 higher odds to develop carboplatin/taxane-induced GI toxicity (P<0.01). Variants in the VEGF gene were marginally associated with survival time. Our data provide potential targets for modulation/inhibition of GI toxicity in ovarian cancer patients. PMID:26194361

  19. PHD Inhibition Mitigates and Protects Against Radiation-Induced Gastrointestinal Toxicity via HIF2

    PubMed Central

    Taniguchi, Cullen M.; Miao, Yu Rebecca; Diep, Anh N.; Wu, Colleen; Rankin, Erinn B.; Atwood, Todd F.; Xing, Lei; Giaccia, Amato J.

    2014-01-01

    Radiation-induced gastrointestinal (GI) toxicity can be a major source of morbidity and mortality after radiation exposure. There is an unmet need for effective preventative or mitigative treatments against the potentially fatal diarrhea and water loss induced by radiation damage to the GI tract. We report that prolyl hydroxylase inhibition by genetic knockout or pharmacologic inhibition of all PHD isoforms by the small molecule dimethyloxyallylglycine (DMOG) increases HIF expression, improves epithelial integrity, reduces apoptosis, and increases intestinal angiogenesis, all of which are essential for radioprotection. HIF2, but not HIF1, is both necessary and sufficient to prevent radiation-induced GI toxicity and death. Increased VEGF expression contributes to the protective effects of HIF2, since inhibition of VEGF function reversed the radioprotection and radiomitigation afforded by DMOG. Additionally, mortality is reduced from abdominal or total body irradiation even when DMOG is given 24 hours after exposure. Thus, prolyl hydroxylase inhibition represents a new treatment strategy to protect against and mitigate GI toxicity from both therapeutic radiation and potentially lethal radiation exposures. PMID:24828078

  20. Abatement of morphine-induced slowing in gastrointestinal transit by Dai-kenchu-to, a traditional Japanese herbal medicine.

    PubMed

    Nakamura, Tomonori; Sakai, Akiko; Isogami, Issei; Noda, Kazuhiro; Ueno, Koichi; Yano, Shingo

    2002-02-01

    As a way of alleviating severe constipation in cancer patients taking morphine to relieve pain, effects of Dai-kenchu-to (DKT), a traditional Japanese herbal medicine (Kampo medicine), on gastrointestinal transit in mice or on the isolated guinea pig ileum were studied in special reference to morphine. Without altering the anti-nociceptive effect of morphine, DKT was significantly effective against morphine-induced disorder of gastrointestinal transit in mice as assessed by the charcoal meal test for the intestine and measurement of transit time for the colon tract. The results of in vitro studies with guinea pig ileum suggest that abatement of morphine-induced disorder of transit by DKT is caused by both moderate contraction of morphine-treated longitudinal muscle and relaxation of morphine-induced tonic contraction of circular muscle. PMID:11928724

  1. Biodegradable microspheres for parenteral delivery.

    PubMed

    Sinha, V R; Trehan, A

    2005-01-01

    Nowadays, emphasis is being laid to development of controlled release dosage forms. Interest in this technology has increased steadily over the past few years. Although oral administration of drugs is a widely accepted route of drug delivery, bioavailability of drug often varies as a result of gastrointestinal absorption, degradation by first-pass effect, and hostile environment of gastrointestinal tract. Transdermal administration for percutaneous absorption of drug is limited by the impermeable nature of the stratum corneum. Ocular and nasal delivery is also unfavorable because of degradation by enzymes present in eye tissues and nasal mucosa. Hence, the parenteral route is the most viable approach in such cases. Of the various ways of achieving long-term parenteral drug delivery, biodegradable microspheres are one of the better means of controlling the release of drug over a long time. Because of the lipidic nature of liposomes, problems such as limited physical stability and difficulty of freeze-drying are encountered. Similarly, for emulsions, stability on long-term basis and in suspensions, rheological changes during filling, injecting, and storage poses limitation. Also, in all these systems, the release rate cannot be tailored to the needs of the patient. Parenteral controlled-release formulations based on biodegradable microspheres can overcome these problems and can control the release of drug over a predetermined time span, usually in the order of days to weeks to months. Various FDA-approved controlled-release parenteral formulations based on these biodegradable microspheres are available on the market, including Lupron Depot Nutropin Depot and Zoladex. This review covers various molecules encapsulated in biodegradable microspheres for parenteral delivery. PMID:16566705

  2. Microradiographic microsphere manipulator

    DOEpatents

    Singleton, Russell M.

    1980-01-01

    A method and apparatus for radiographic characterization of small hollow spherical members (microspheres), constructed of either optically transparent or opaque materials. The apparatus involves a microsphere manipulator which holds a batch of microspheres between two parallel thin plastic films for contact microradiographic characterization or projection microradiography thereof. One plastic film is translated to relative to and parallel to the other to roll the microspheres through any desired angle to allow different views of the microspheres.

  3. Microradiographic microsphere manipulator

    DOEpatents

    Singleton, R.M.

    A method and apparatus is disclosed for radiographic characterization of small hollow spherical members (microspheres), constructed of either optically transparent or opaque materials. The apparatus involves a microsphere manipulator which holds a batch of microspheres between two parallel thin plastic films for contact microradiographic characterization or projection microradiography thereof. One plastic film is translated relative to and parallel to the other to roll the microspheres through any desired angle to allow different views of the microspheres.

  4. Albumin microspheres for oral delivery of iron.

    PubMed

    Shivakumar, H N; Vaka, Siva Ram Kiran; Murthy, S Narasimha

    2010-01-01

    Bovine serum albumin (BSA) microspheres of ferric pyrophosphate (FPP) intended for passive targeting to the Peyer's patches has been proposed for oral iron supplementation. Microspheres prepared by emulsification chemical cross linking method were characterized for surface topography, entrapment efficiency, particle size, particle charge and in vitro drug release. Microspheres of batch C with FPP to BSA ratio of 1:5 were found to be most suitable for targeting as they exhibited high entrapment (83.88 +/- 4.31), high monodispersity (span = 1.24 +/- 0.01), and least particle size (d(vm) = 4.40 +/- 0.01). In addition the amount of iron retained in these microspheres despite exposure to simulated gastrointestinal conditions for 5 h was found to be 83.72 +/- 4.22%, the highest in the three batches. The in vivo serum iron profiles in normal rats following oral administration displayed a reduced T(max) (2 h), elevated C(max) (106.06 +/- 12.18 mug/dL) and increased AUC (0-16 h) (647.44 +/- 52.33 mug.h/dL) for these microspheres which significantly differed (P <0.05) from FPP solution indicating a higher iron repletion potential of the BSA microspheres. PMID:19635031

  5. Pretreatment with the inducers rifampicin and phenobarbital alters ivermectin gastrointestinal disposition.

    PubMed

    Ballent, M; Lifschitz, A; Virkel, G; Mate, L; Lanusse, C

    2010-06-01

    The goal of the study was to evaluate the effects of rifampicin (RFP) and phenobarbital (PBT) on the plasma and gastrointestinal disposition kinetics of ivermectin (IVM) subcutaneously administered to Wistar rats. Fifty seven rats were used. Animals in Group I were the noninduced (control) group. Those in Groups II and III received a treatment with RFP (160 mg/day) and PBT (35 mg/day), respectively, both given orally during eight consecutive days as induction regimen. The IVM pharmacokinetic study was started 24 h after the RFP and PBT last administration. Animals received IVM (200 microg/kg) by subcutaneous injection. Rats were sacrificed between 6 h and 3 days after IVM administration. Blood and samples of liver tissue, intestinal wall and luminal content of jejunum were collected from each animal. IVM concentrations were measured by high performance liquid chromatography. IVM disposition kinetics in plasma and tissues was significantly modified by the PBT treatment, but not by RFP. Despite the enhanced CYP3A activity observed after the pretreatment with RPF and PBT, there were no marked changes on the percentages of IVM metabolites recovered from the bloodstream in induced and noninduced animals. An enhanced P-glycoprotein-mediated intestinal transport activity in pretreated animals (particularly in PBT pretreated rats) may explain the drastic changes observed on IVM disposition. PMID:20557442

  6. No Significant Endothelial Apoptosis in the Radiation-Induced Gastrointestinal Syndrome

    SciTech Connect

    Schuller, Bradley W.; Rogers, Arlin B.; Cormier, Kathleen S.; Riley, Kent J.; Binns, Peter J.; Julius, Richard; Hawthorne, M. Frederick; Coderre, Jeffrey A. . E-mail: coderre@mit.edu

    2007-05-01

    Purpose: This report addresses the incidence of vascular endothelial cell apoptosis in the mouse small intestine in relation to the radiation-induced gastrointestinal (GI) syndrome. Methods and Materials: Nonanesthetized mice received whole-body irradiation at doses above and below the threshold for death from the GI syndrome with 250 kVp X-rays, {sup 137}Cs gamma rays, epithermal neutrons alone, or a unique approach for selective vascular irradiation using epithermal neutrons in combination with boronated liposomes that are restricted to the blood. Both terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling (TUNEL) staining for apoptosis and dual-fluorescence staining for apoptosis and endothelial cells were carried out in jejunal cross-sections at 4 h postirradiation. Results: Most apoptotic cells were in the crypt epithelium. The number of TUNEL-positive nuclei per villus was low (1.62 {+-} 0.03, mean {+-} SEM) for all irradiation modalities and showed no dose-response as a function of blood vessel dose, even as the dose crossed the threshold for death from the GI syndrome. Dual-fluorescence staining for apoptosis and endothelial cells verified the TUNEL results and identified the apoptotic nuclei in the villi as CD45-positive leukocytes. Conclusion: These data do not support the hypothesis that vascular endothelial cell apoptosis is the cause of the GI syndrome.

  7. Ionizing irradiation induces acute haematopoietic syndrome and gastrointestinal syndrome independently in mice.

    PubMed

    Leibowitz, Brian J; Wei, Liang; Zhang, Lin; Ping, Xiaochun; Epperly, Michael; Greenberger, Joel; Cheng, Tao; Yu, Jian

    2014-01-01

    The role of bone marrow (BM) and BM-derived cells in radiation-induced acute gastrointestinal (GI) syndrome is controversial. Here we use bone marrow transplantation (BMT), total body irradiation (TBI) and abdominal irradiation (ABI) models to demonstrate a very limited, if any, role of BM-derived cells in acute GI injury and recovery. Compared with WT BM recipients, mice receiving BM from radiation-resistant PUMA KO mice show no protection from crypt and villus injury or recovery after 15 or 12 Gy TBI, but have a significant survival benefit at 12 Gy TBI. PUMA KO BM significantly protects donor-derived pan-intestinal haematopoietic (CD45+) and endothelial (CD105+) cells after IR. We further show that PUMA KO BM fails to enhance animal survival or crypt regeneration in radiosensitive p21 KO-recipient mice. These findings clearly separate the effects of radiation on the intestinal epithelium from those on the BM and endothelial cells in dose-dependent acute radiation toxicity. PMID:24637717

  8. Ionizing irradiation induces acute haematopoietic syndrome and gastrointestinal syndrome independently in mice

    PubMed Central

    Leibowitz, Brian J.; Wei, Liang; Zhang, Lin; Ping, Xiaochun; Epperly, Michael; Greenberger, Joel; Cheng, Tao; Yu, Jian

    2015-01-01

    The role of bone marrow (BM) and BM-derived cells in radiation-induced acute gastrointestinal (GI) syndrome is controversial. Here we use bone marrow transplantation (BMT), total body irradiation (TBI) and abdominal irradiation (ABI) models to demonstrate a very limited, if any, role of BM-derived cells in acute GI injury and recovery. Compared with WT BM recipients, mice receiving BM from radiation-resistant PUMA KO mice show no protection from crypt and villus injury or recovery after 15 or 12 Gy TBI, but have a significant survival benefit at 12 Gy TBI. PUMA KO BM significantly protects donor-derived pan-intestinal haematopoietic (CD45 +) and endothelial (CD105 +) cells after IR. We further show that PUMA KO BM fails to enhance animal survival or crypt regeneration in radiosensitive p21 KO-recipient mice. These findings clearly separate the effects of radiation on the intestinal epithelium from those on the BM and endothelial cells in dose-dependent acute radiation toxicity. PMID:24637717

  9. Metabolic microspheres

    NASA Astrophysics Data System (ADS)

    Fox, Sidney W.

    1980-08-01

    A systematic review of catalytic activities in thermal proteinoids and microspheres aggregated therefrom yields some new inferences on the origins and evolution of metabolism. Experiments suggest that, instead of being inert, protocells were already biochemically and cytophysically competent. The emergence and refinement of metabolism ab initio is thus partly traced conceptually. When the principle of molecular self-instruction, as of amino acids in peptide synthesis, is taken into account as a concomitant of natural selection, an expanded theory of organismic evolution, including saltations, emerges.

  10. Hybrid microspheres

    NASA Technical Reports Server (NTRS)

    Rembaum, Alan (Inventor); Yen, Richard C. K. (Inventor)

    1985-01-01

    Substrates, particularly inert synthetic organic resin beads (10) or sheet (12) such as polystyrene are coated with a covalently bound layer (24) of polyacrolein by irradiation a solution (14) of acrolein or other aldehyde with high intensity radiation. Individual microspheres (22) are formed which attach to the surface to form the aldehyde containing layer (24). The aldehyde groups can be converted to other functional groups by reaction with materials such as hydroxylamine. Adducts of proteins such as antibodies or enzymes can be formed by direct reaction with the surface aldehyde groups.

  11. Keratinocyte growth factor induces proliferation of hepatocytes and epithelial cells throughout the rat gastrointestinal tract.

    PubMed Central

    Housley, R M; Morris, C F; Boyle, W; Ring, B; Biltz, R; Tarpley, J E; Aukerman, S L; Devine, P L; Whitehead, R H; Pierce, G F

    1994-01-01

    Keratinocyte growth factor (KGF), a member of the fibroblast growth factor (FGF) family, was identified as a specific keratinocyte mitogen after isolation from a lung fibroblast line. Recently, recombinant (r)KGF was found to influence proliferation and differentiation patterns of multiple epithelial cell lineages within skin, lung, and the reproductive tract. In the present study, we designed experiments to identify additional target tissues, and focused on the rat gastrointestinal (GI) system, since a putative receptor, K-sam, was originally identified in a gastric carcinoma. Expression of KGF receptor and KGF mRNA was detected within the entire GI tract, suggesting the gut both synthesized and responded to KGF. Therefore, rKGF was administered to adult rats and was found to induce markedly increased proliferation of epithelial cells from the foregut to the colon, and of hepatocytes, one day after systemic treatment. Daily treatment resulted in the marked selective induction of mucin-producing cell lineages throughout the GI tract in a dose-dependent fashion. Other cell lineages were either unaffected (e.g., Paneth cells), or relatively decreased (e.g., parietal cells, enterocytes) in rKGF-treated rats. The direct effect of rKGF was confirmed by demonstrating markedly increased carcinoembryonic antigen production in a human colon carcinoma cell line, LIM1899. Serum levels of albumin were specifically and significantly elevated after daily treatment. These results demonstrate rKGF can induce epithelial cell activation throughout the GI tract and liver. Further, endogenous KGF may be a normal paracrine mediator of growth within the gut. Images PMID:7962522

  12. Balancing opioid-induced gastrointestinal side effects with pain management: Insights from the online community.

    PubMed

    Whitman, Cynthia B; Reid, Mark W; Arnold, Corey; Patel, Haridarshan; Ursos, Lyann; Sa'adon, Roee; Pourmorady, Jonathan; Spiegel, Brennan M R

    2015-01-01

    Opioids cause gastrointestinal (GI) symptoms such as nausea, vomiting, pain, and (in 40 percent) constipation that diminish patients' quality of life. Outside traditional surveys, little is known about the opioid-induced constipation (OIC) patient experience and its impact on pain management. The purpose of this study was to use data from social media platforms to qualitatively examine patient beliefs about OIC and other prominent GI side effects, their impact on effective pain management and doctor-patient interaction. The authors collected Tweets from March 25 to July 31, 2014, and e-forum posts from health-related social networking sites regardless of timestamp. The authors identified specific keywords related to opioids and GI side effects to locate relevant content in the dataset, which was then manually coded using ATLAS.ti software. The authors examined 2,519,868 Tweets and more than 1.8 billion e-forum posts, of which, 88,586 Tweets and 9,767 posts satisfied the search criteria. Three thousand three individuals experienced opioidinduced GI side effects, mostly related to phenanthrenes (n = 1,589), and 1,274 (42.4 percent) individuals described constipation. Over-the-counter medications and nonevidence-based natural approaches were most commonly used to alleviate constipation. Many individuals questioned, rotated, reduced, or stopped their opioid treatments as a result of their GI side effects. Investigation of social media reveals a struggle to balance pain management with opioid-induced GI side effects, especially constipation. Individuals are often unprepared to treat OIC, to modify opioid regiments without medical advice, and to resort to using natural remedies and treatments lacking scientific evidence of effectiveness. These results identify opportunities to improve physician-patient communication and explore effective treatment alternatives. PMID:26535966

  13. Lactose maldigestion during methotrexate-induced gastrointestinal mucositis in a rat model.

    PubMed

    Fijlstra, M; Rings, E H H M; Verkade, H J; van Dijk, T H; Kamps, W A; Tissing, W J E

    2011-02-01

    Patients with chemotherapy-induced gastrointestinal mucositis suffer from anorexia, diarrhea, and stomach pain, often causing weight loss and malnutrition. When the intestinal function during mucositis would be known, a rational feeding strategy might improve the nutritional state, accelerate recuperation, and increase survival of mucositis patients. We developed a methotrexate (MTX)-induced mucositis rat model to study nutrient digestion and absorption. To determine lactose digestion and absorption of its derivative glucose during mucositis, we injected Wistar rats intravenously with MTX (60 mg/kg) or 0.9% NaCl (controls). Four days later, we orally administered trace amounts of [1-(13)C]lactose and [U-(13)C]glucose and quantified the appearance of labeled glucose in the blood for 3 h. Finally, we determined plasma citrulline level and harvested the small intestine to assess histology, myeloperoxidase level, glycohydrolase activity, immunohistochemical protein, and mRNA expression. MTX-treated rats showed profound villus atrophy and epithelial damage. During the experimental period, the absorption of lactose-derived [1-(13)C]glucose was 4.2-fold decreased in MTX-treated rats compared with controls (P < 0.01). Lactose-derived [1-(13)C]glucose absorption correlated strongly with villus length (rho = 0.86, P < 0.001) and with plasma citrulline level (rho = 0.81, P < 0.001). MTX treatment decreased jejunal lactase activity (19.5-fold, P < 0.01) and immunohistochemical protein and mRNA expression (39.7-fold, P < 0.01) compared with controls. Interestingly, MTX treatment did not affect the absorption of [U-(13)C]glucose during the experimental period. We conclude that lactose digestion is severely decreased during mucositis while glucose absorption is still intact, when supplied in trace amounts. Plasma citrulline level might be a useful objective, noninvasive marker for lactose maldigestion during mucositis in clinic. PMID:21088238

  14. Mucoadhesivity Characterization of Isabgol Husk Mucilage Microspheres Crosslinked by Glutaraldehyde.

    PubMed

    Sharma, Vipin Kumar; Sharma, Prince Prashant; Mazumder, Bhasker; Bhatnagar, Aseem; Singh, Thakuri

    2015-01-01

    The microspheres of Isabgol husk were prepared by emulsification-crosslinking technique and the gastrointestinal transition behavior of the formulation was studied by gamma scintigraphy. The impact of different process variables such as amount of glutaraldehyde, concentration of Isabgol husk and temperature was studied on surface morphology and mucoadhesion. In vitro mucoadhesive testing of formulations was performed by determination of zeta potential, mucus glycoprotein assay and mucus adsorption isotherms. The effect of feeding on retention of microspheres in the gastrointestinal track (GIT) was studied in albino rabbits by gamma scintigraphy study. The results indicated the formation of microspheres as observed by scanning electron microscopy. The smooth and round surfaces of microspheres were obtained on increasing Isabgol husk and glutaraldehyde amount. The positive zeta potential of all formulations indicated the electrostatic interaction as a mechanism of mucoadhesion between the mucus of GIT membranes and the microspheres surfaces. The influence of electrostatic interaction on mucoadhesion of microspheres was again ascertained when the mucin equilibrium adsorption on preparations indicated well fitness in Langmuir and Freundlich adsorption isotherms. During gamma scintigraphy, the stability of (99m)Tc-sodium pertechnetate was found 98.82% at pH 6.8 and 96.78% at pH 7.2, respectively. It indicated the minimal leaching of bound radionuclide from microspheres during gastrointestinal transition as observed in gamma scintigraphic images of the rabbits. The microspheres retained in GIT even after 24 hrs of oral administration. The results indicated the applicability of Isabgol husk mucilage in the development of mucoadhesive microspheres. PMID:25675337

  15. Kinetics of piroxicam release from low-methylated pectin/zein hydrogel microspheres

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The kinetics of a model drug (piroxicam) release from pectin/zein hydrogel microspheres was studied under conditions simulating the gastrointestinal tract. It is established that the rate-limiting step in the release mechanism is drug diffusion out of the microspheres rather than its dissolution. ...

  16. Pitch carbon microsphere composite

    NASA Technical Reports Server (NTRS)

    Price, H. L.; Nelson, J. B.

    1977-01-01

    Petroleum pitch carbon microspheres were prepared by flash heating emulsified pitch and carbonizing the resulting microspheres in an inert atmosphere. Microsphere composites were obtained from a mixture of microspheres and tetraester precursor pyrrone powder. Scanning electron micrographs of the composite showed that it was an aggregate of microspheres bonded together by the pyrrone at the sphere contact points, with voids in and among the microspheres. Physical, thermal, and sorption properties of the composite are described. Composite applications could include use as a honeycomb filler in elevated-temperature load-bearing sandwich boards or in patient-treatment tables for radiation treatment of tumors.

  17. Ex vivo optical coherence tomography and laser induced fluorescence spectroscopy imaging of murine gastrointestinal tract

    NASA Astrophysics Data System (ADS)

    Hariri, Lida; Tumlinson, Alexandre R.; Wade, Norman; Besselsen, David; Utzinger, Urs; Gerner, Eugene; Barton, Jennifer

    2005-04-01

    Optical Coherence Tomography (OCT) and Laser Induced Fluorescence Spectroscopy (LIF) have separately been found to have clinical potential in identifying human gastrointestinal (GI) pathologies, yet their diagnostic capability in mouse models of human disease is unknown. We combine the two modalities to survey the GI tract of a variety of mouse strains and sample dysplasias and inflammatory bowel disease (IBD) of the small and large intestine. Segments of duodenum and lower colon 2.5 cm in length and the entire esophagus from 10 mice each of two colon cancer models (ApcMin and AOM treated A/J) and two IBD models (Il-2 and Il-10) and 5 mice each of their respective controls were excised. OCT images and LIF spectra were obtained simultaneously from each tissue sample within 1 hour of extraction. Histology was used to classify tissue regions as normal, Peyer"s patch, dysplasia, adenoma, or IBD. Features in corresponding regions of OCT images were analyzed. Spectra from each of these categories were averaged and compared via the student's t-test. Features in OCT images correlated to histology in both normal and diseased tissue samples. In the diseased samples, OCT was able to identify early stages of mild colitis and dysplasia. In the sample of IBD, the LIF spectra displayed unique peaks at 635nm and 670nm, which were attributed to increased porphyrin production in the proliferating bacteria of the disease. These peaks have the potential to act as a diagnostic for IBD. OCT and LIF appear to be useful and complementary modalities for imaging mouse models.

  18. Detection of Treatment-Induced Changes in Signaling Pathways in Gastrointestinal Stromal Tumors using Transcriptomic Data

    PubMed Central

    Ochs, Michael F.; Rink, Lori; Tarn, Chi; Mburu, Sarah; Taguchi, Takahiro; Eisenberg, Burton; Godwin, Andrew K.

    2009-01-01

    Cell signaling plays a central role in the etiology of cancer. Numerous therapeutics in use or under development target signaling proteins, however off-target effects often limit assignment of positive clinical response to the intended target. As direct measurements of signaling protein activity are not generally feasible during treatment, there is a need for more powerful methods to determine if therapeutics inhibit their targets and when off-target effects occur. We have used the Bayesian Decomposition algorithm and data on transcriptional regulation to create a novel methodology, DESIDE (Differential Expression for SIgnaling DEtermination), for inferring signaling activity from microarray measurements. We applied DESIDE to deduce signaling activity in gastrointestinal stromal tumor cell lines treated with the targeted therapeutic imatinib mesylate (Gleevec). We detected the expected reduced activity in the KIT pathway, as well as unexpected changes in the P53 pathway. Pursuing these findings, we have determined that imatinib-induced DNA damage is responsible for the increased activity of P53, identifying a novel off-target activity for this drug. We then used DESIDE on data from resected, post-imatinib treatment tumor samples and identified a pattern in these tumors similar to that at late time points in the cell lines, and this pattern correlated with initial clinical response. The pattern showed increased activity of ELK1 and STAT3 transcription factors, which are associated with the growth of side population cells. DESIDE infers the global reprogramming of signaling networks during treatment, permitting treatment modification that leverages ongoing drug development efforts, which is crucial for personalized medicine. PMID:19903850

  19. Hydrogel microspheres for stabilization of an antioxidant enzyme: effect of emulsion cross-linking of a dual polysaccharide system on the protection of enzyme activity.

    PubMed

    Tang, Deh-Wei; Yu, Shu-Huei; Wu, Wen-Shin; Hsieh, Hao-Ying; Tsai, Yi-Chin; Mi, Fwu-Long

    2014-01-01

    Catalase is an antioxidant enzyme abundant in natural resources. However, the enzyme is usually inactivated by gastric acid and digestive enzymes after oral ingestion. In this study, carboxymethyl chitosan (CM-chitosan) and hyaluronic acid (HA) conjugate hydrogel microspheres have been prepared by an emulsion cross-linking technique to retain the activity of catalase in simulated gastrointestinal (GI) fluids. Cross-linking reduced the swelling capability and increased the resistance toward hyaluronidase digestion of prepared HA-CM-chitosan hydrogel microspheres. Catalase entrapped in the hydrogel microspheres exhibited superior stability over a wide pH range (pH 2.0 and 6.0-8.0) as compared to the native enzyme. The entrapped catalase was also protected against degradation by digestive enzymes. Following the treatments, the catalase-loaded microspheres, in contrast to native catalase, could effectively decrease the intracellular H2O2 level and protect HT-29 colonic epithelial cells against H2O2-induced oxidative damage to preserve cell viability. These results suggested that the HA-CM-chitosan hydrogel microspheres can be used for entrapment, protection and intestinal delivery of catalase for H2O2 scavenging. PMID:24055882

  20. Systemic treatment-induced gastrointestinal toxicity: incidence, clinical presentation and management

    PubMed Central

    Boussios, Stergios; Pentheroudakis, George; Katsanos, Konstantinos; Pavlidis, Nicholas

    2012-01-01

    The toxicity of cancer chemotherapy is among the most important factors limiting its use. Clear delineation and communication of benefits and risks is an essential component of treatment decisions. Gastrointestinal toxicity during chemotherapy is frequent and contributes to dose reductions, delays and cessation of cancer treatment. The development of intervention strategies that could eliminate an expected side effect of chemotherapy is vital. Physiologic changes that can increase the toxicity of chemotherapy are decreased stem cell reserves, decreased ability to repair cell damage, progressive loss of body protein, and accumulation of body fat. Symptoms only arise when physiological functions are altered. The gastrointestinal symptoms arising during cancer chemotherapy can often be cured if newly acquired, and if gastrointestinal physiological deficits are identified. Developing new chemotherapy regimens with similar efficacy but less toxicity should be a priority for future research. PMID:24713845

  1. Milk protein IgG and IgA: The association with milk-induced gastrointestinal symptoms in adults

    PubMed Central

    Anthoni, Sari; Savilahti, Erkki; Rautelin, Hilpi; Kolho, Kaija-Leena

    2009-01-01

    of the subjects increased (P < 0.004). CONCLUSION: Milk protein IgG but not milk IgA seems to be associated with self-reported milk-induced gastrointestinal symptoms. PMID:19842221

  2. Optimization of sustained release aceclofenac microspheres using response surface methodology.

    PubMed

    Deshmukh, Rameshwar K; Naik, Jitendra B

    2015-03-01

    Polymeric microspheres containing aceclofenac were prepared by single emulsion (oil-in-water) solvent evaporation method using response surface methodology (RSM). Microspheres were prepared by changing formulation variables such as the amount of Eudragit® RS100 and the amount of polyvinyl alcohol (PVA) by statistical experimental design in order to enhance the encapsulation efficiency (E.E.) of the microspheres. The resultant microspheres were evaluated for their size, morphology, E.E., and in vitro drug release. The amount of Eudragit® RS100 and the amount of PVA were found to be significant factors respectively for determining the E.E. of the microspheres. A linear mathematical model equation fitted to the data was used to predict the E.E. in the optimal region. Optimized formulation of microspheres was prepared using optimal process variables setting in order to evaluate the optimization capability of the models generated according to IV-optimal design. The microspheres showed high E.E. (74.14±0.015% to 85.34±0.011%) and suitably sustained drug release (minimum; 40% to 60%; maximum) over a period of 12h. The optimized microspheres formulation showed E.E. of 84.87±0.005 with small error value (1.39). The low magnitudes of error and the significant value of R(2) in the present investigation prove the high prognostic ability of the design. The absence of interactions between drug and polymers was confirmed by Fourier transform infrared (FTIR) spectroscopy. Differential scanning calorimetry (DSC) and X-ray powder diffractometry (XRPD) revealed the dispersion of drug within microspheres formulation. The microspheres were found to be discrete, spherical with smooth surface. The results demonstrate that these microspheres could be promising delivery system to sustain the drug release and improve the E.E. thus prolong drug action and achieve the highest healing effect with minimal gastrointestinal side effects. PMID:25579914

  3. Efficacy of oral afoxolaner plus milbemycin oxime chewables against induced gastrointestinal nematode infections in dogs.

    PubMed

    Fankhauser, Rebecca; Hamel, Dietmar; Dorr, Paul; Reinemeyer, Craig R; Crafford, Dionne; Bowman, Dwight D; Ulrich, Michael; Yoon, Stephen; Larsen, Diane L

    2016-07-30

    The efficacy of oral afoxolaner plus milbemycin oxime combination chewables against induced gastrointestinal nematode infections in dogs was evaluated in six separate studies. Two studies were performed to evaluate the efficacy of the product against Toxocara canis, two studies evaluated the efficacy against Toxascaris leonina, one study evaluated the efficacy against Ancylostoma braziliense, and one study evaluated the efficacy against Ancylostoma caninum. In the A. caninum study, the efficacy of milbemycin oxime alone and afoxolaner alone was also evaluated. Dogs in all studies were inoculated with infective eggs or larvae and confirmed to have patent infections based on a fecal examination prior to allocation to study group and treatment. Each study utilized a randomized block design with blocks based on pre-treatment body weight. All dogs were assigned to blocks based on body weight, and then each dog within a block was randomly assigned to treatment group. There were two groups of 10 dogs each in the T. canis, T. leonina, and A. braziliense studies: 1) an untreated (control) group and 2) a group treated with afoxolaner plus milbemycin oxime chewables (NexGard Spectra(®), Merial). This group was treated at a dose as close as possible to the minimum effective dose of afoxolaner and milbemycin oxime (2.5mg+0.5mg per kg body weight, respectively) once on Day 0 using whole chews. There were four groups of 10 dogs each in the A. caninum study: 1) untreated (control), 2) NexGard Spectra(®) as described above, 3) milbemycin oxime alone (dose of at least 0.5mg per kg of body weight) and 4) afoxalaner alone (dose of at least 2.5mg per kg body weight). For parasite recovery and counts, dogs were euthanized humanely and necropsied seven days after treatment. The efficacy of the afoxolaner plus milbemycin oxime combination was ≥98% against T. canis, ≥95.8% against T. leonina, and 90.2% against A. braziliense. Efficacy of the combination against A. caninum was 99

  4. A Novel Method for Differentiation of Human Mesenchymal Stem Cells into Smooth Muscle-Like Cells on Clinically Deliverable Thermally Induced Phase Separation Microspheres

    PubMed Central

    Parmar, Nina; Ahmadi, Raheleh

    2015-01-01

    Muscle degeneration is a prevalent disease, particularly in aging societies where it has a huge impact on quality of life and incurs colossal health costs. Suitable donor sources of smooth muscle cells are limited and minimally invasive therapeutic approaches are sought that will augment muscle volume by delivering cells to damaged or degenerated areas of muscle. For the first time, we report the use of highly porous microcarriers produced using thermally induced phase separation (TIPS) to expand and differentiate adipose-derived mesenchymal stem cells (AdMSCs) into smooth muscle-like cells in a format that requires minimal manipulation before clinical delivery. AdMSCs readily attached to the surface of TIPS microcarriers and proliferated while maintained in suspension culture for 12 days. Switching the incubation medium to a differentiation medium containing 2 ng/mL transforming growth factor beta-1 resulted in a significant increase in both the mRNA and protein expression of cell contractile apparatus components caldesmon, calponin, and myosin heavy chains, indicative of a smooth muscle cell-like phenotype. Growth of smooth muscle cells on the surface of the microcarriers caused no change to the integrity of the polymer microspheres making them suitable for a cell-delivery vehicle. Our results indicate that TIPS microspheres provide an ideal substrate for the expansion and differentiation of AdMSCs into smooth muscle-like cells as well as a microcarrier delivery vehicle for the attached cells ready for therapeutic applications. PMID:25205072

  5. microsphere assemblies

    NASA Astrophysics Data System (ADS)

    Peña-Flores, Jesús I.; Palomec-Garfias, Abraham F.; Márquez-Beltrán, César; Sánchez-Mora, Enrique; Gómez-Barojas, Estela; Pérez-Rodríguez, Felipe

    2014-09-01

    The effect of Fe ion concentration on the morphological, structural, and optical properties of TiO2 films supported on silica (SiO2) opals has been studied. TiO2:Fe2O3 films were prepared by the sol-gel method in combination with a vertical dip coating procedure; precursor solutions of Ti and Fe were deposited on a monolayer of SiO2 opals previously deposited on a glass substrate by the same procedure. After the dip coating process has been carried out, the samples were thermally treated to obtain the TiO2:Fe2O3/SiO2 composites at the Fe ion concentrations of 1, 3, and 5 wt%. Scanning electron microscopy (SEM) micrographs show the formation of colloidal silica microspheres of about 50 nm diameter autoensembled in a hexagonal close-packed fashion. Although the X-ray diffractograms show no significant effect of Fe ion concentration on the crystal structure of TiO2, the μ-Raman and reflectance spectra do show that the intensity of a phonon vibration mode and the energy bandgap of TiO2 decrease as the Fe+3 ion concentration increases.

  6. Protective effect of wild raspberry (Rubus hirsutus Thunb.) extract against acrylamide-induced oxidative damage is potentiated after simulated gastrointestinal digestion.

    PubMed

    Chen, Wei; Su, Hongming; Xu, Yang; Bao, Tao; Zheng, Xiaodong

    2016-04-01

    Raspberry is well known as rich source of antioxidants, such as polyphenols and flavonoids. However, after consumption, the antioxidants are subjected to digestive conditions within the gastrointestinal tract that may result in structural and functional alterations. Our previous study indicated that acrylamide (AA)-induced cytotoxicity was associated with oxidative stress. However, the protective effect of wild raspberry extract produced before and after in vitro gastrointestinal digestion against AA-induced oxidative damage is unclear. In the present study, we found that wild raspberry extract produced after digestion (RD) had a pronounced protective effect against AA-induced cytotoxicity compared with that produced before digestion (RE). Further investigation indicated that RD significantly inhibited AA-induced intracellular reactive oxygen species (ROS) generation, mitochondrial membrane potential (MMP) collapse and glutathione (GSH) depletion. Moreover, LC-MS analysis revealed that wild raspberry underwent gastrointestinal digestion significantly increased the contents of esculin, kaempferol hexoside and pelargonidin hexoside. PMID:26593576

  7. Assembly of functional gold nanoparticle on silica microsphere.

    PubMed

    Wang, Hsuan-Lan; Lee, Fu-Cheng; Tang, Tse-Yu; Zhou, Chenguang; Tsai, De-Hao

    2016-05-01

    We demonstrate a controlled synthesis of silica microsphere with the surface-decorated functional gold nanoparticles. Surface of silica microsphere was modified by 3-aminopropypltriethoxysilane and 3-aminopropyldimethylethoxysilane to generate a positive electric field, by which the gold nanoparticles with the negative charges (unconjugated, thiolated polyethylene glycol functionalized with the traceable packing density and conformation) were able to be attracted to the silica microsphere. Results show that both the molecular conjugation on gold nanoparticle and the uniformity in the amino-silanization of silica microsphere influenced the loading and the homogeneity of gold nanoparticles on silica microsphere. The 3-aminopropyldimethylethoxysilane-functionalized silica microsphere provided an uniform field to attract gold nanoparticles. Increasing the ethanol content in aminosilane solution significantly improved the homogeneity and the loading of gold nanoparticles on the surface of silica microsphere. For the gold nanoparticle, increasing the molecular mass of polyethylene glycol yielded a greater homogeneity but a lower loading on silica microsphere. Bovine serum albumin induced the desorption of gold nanoparticles from silica microsphere, where the extent of desorption was suppressed by the presence of high-molecular mass polyethylene glycol on gold nanoparticles. This work provides the fundamental understanding for the synthesis of gold nanoparticle-silica microsphere constructs useful to the applications in chemo-radioactive therapeutics. PMID:26874272

  8. Laser-assisted fabrication of highly viscous alginate microsphere

    NASA Astrophysics Data System (ADS)

    Lin, Yafu; Huang, Yong

    2011-04-01

    Encapsulated microspheres have been widely used in various biomedical applications. However, fabrication of encapsulated microspheres from highly viscous materials has always been a manufacturing challenge. The objective of this study is to explore a novel metallic foil-assisted laser-induced forward transfer (LIFT), a laser-assisted fabrication technique, to make encapsulated microspheres using high sodium alginate concentration solutions. The proposed four-layer approach includes a quartz disk, a sacrificial and adhesive layer, a metallic foil, and a transferred suspension layer. It is found that the proposed four-layer modified LIFT approach provides a promising fabrication technology for making of bead-encapsulated microspheres from highly viscous solutions. During the process, the microsphere only can be formed if the direct-writing height is larger than the critical direct-writing height; otherwise, tail structured droplets are formed; and the encapsulated microsphere diameter linearly increases with the laser fluence and decreases with the sodium alginate concentration.

  9. Microfluidic Fabrication of MEAN-Eluting Magnetic Microspheres

    PubMed Central

    Kim, Dong-Hyun; Choy, Terence; Huang, Sui; Green, Richard M; Omary, Reed A.; Larson, Andrew C.

    2014-01-01

    Recently, 6-methoxyethylamino numonafide (MEAN) exhibited potent inhibition of hepatocellular carcinoma (HCC) cell growth and less systemic toxicity than amonafide. MEAN may serve as an ideal candidate for the treatment of HCC; however, liver-directed, selective infusion methods may be critical to maximize MEAN dose delivered to the targeted tumors. Our study describes the microfluidic fabrication of MEAN-eluting ultrasmall superparamagnetic iron oxide (USPIO) nanocluster-containing alginate microspheres (MEAN-magnetic microspheres) intended for selective transcatheter delivery to hepatocellular carcinoma. The resulting drug delivery platform was mono-disperse, microsphere sizes were readily controlled based upon channel flow rates during synthesis procedures, and drug release rates from the microspheres could be readily controlled with the introduction of USPIO nanoclusters. The MR relaxivity properties of the microspheres suggest the feasibility of in vivo imaging after administration and these microspheres exhibited potent therapeutic effects significantly inhibiting cell growth inducing apoptosis in hepatoma cells. PMID:24161384

  10. Patterning of silica microsphere monolayers with focused femtosecond laser pulses

    SciTech Connect

    Cai Wenjian; Piestun, Rafael

    2006-03-13

    We demonstrate the patterning of monolayer silica microsphere lattices with tightly focused femtosecond laser pulses. We selectively removed microspheres from a lattice and characterized the effect on the lattice and the substrate. The proposed physical mechanism for the patterning process is laser-induced breakdown followed by ablation of material. We show that a microsphere focuses radiation in its interior and in the near field. This effect plays an important role in the patterning process by enhancing resolution and accuracy and by reducing the pulse energy threshold for damage. Microsphere patterning could create controlled defects within self-assembled opal photonic crystals.

  11. Interference induced periodic oscillation of convolutional-surface-plasmon resonance for a metal nanoparticle encapsulated by a dielectric microsphere

    NASA Astrophysics Data System (ADS)

    Sun, Song; Liu, Huizhe; Wu, Lin; Eng Png, Ching; Bai, Ping

    2016-07-01

    A theoretical study is performed on the plasmonic properties of a metal nanoparticle encapsulated by a large microsphere, where the microsphere’s diameter is comparable with or larger than the incident wavelength. Due to interaction between the reflected and refracted waves, we show that a unique optical interference (or whisper-gallery-mode-like) pattern is generated inside the microsphere. Such an interference pattern further interacts with the metal nanoparticle embedded inside, which modifies the spectral response of the metal NP and creates a convolutional-surface-plasmon resonance (cSPR). The peak of resultant cSPR oscillates periodically with respect to the microsphere’s diameter due to the repeated occurrence of the constructive and destructive interferences. Our results also show that the periodicity of oscillation is mainly determined by the microsphere’s refractive index, but is less independent on the metal nanoparticle’s size. These findings might be potentially utilized in designing multi-scale plasmon structures in various applications such as sensors, drug delivery and photocatalysis.

  12. Novel Model of Peripheral Tissue Trauma Induced Inflammation and Gastrointestinal Dysmotility

    PubMed Central

    Tsukamoto, Takeshi; Antonic, Vlado; El Hajj, Ihab I.; Stojadinovic, Alexander; Binion, David G.; Izadjoo, Mina J.; Yokota, Hiroyuki; Pape, Hans Christoph; Bauer, Anthony J.

    2011-01-01

    Background Trauma is a leading cause of death and although the gut is recognized as the “motor” of post-traumatic systemic inflammatory response syndrome and multiple organ failure, studies on the gastrointestinal tract are few. Our objectives were to create a precisely controllable tissue injury model in which gastrointestinal motility, systemic inflammation and wound fluid can be analyzed. Methods A non-narcotic murine trauma model was developed by the subcutaneous dorsal trans-implantation of a devitalized donor syngeneic harvested tissue-bone matrix (TBX), which was precisely adjusted to % total body weight and studied after 21 hrs. Gastrointestinal transit histograms were plotted after the oral administration of non-digestible FITC-dextran and geometric centers calculated. Organ bath evaluated jejunal circular muscle contractility. Multiplex electrochemiluminescence measurements of serum and TBX wound fluid inflammatory mediators were performed. Key Results Increasing TBX amounts progressively delayed transit, whereas TBX heat denaturation or decellularization prevented ileus and death. In the TBX17.5% model, jejunal muscle contractility was suppressed and a systemic inflammatory response developed as significant serum elevations in IL-6, keratinocyte cytokine and IL-10 compared to sham. Additionally, inflammatory responses within the wound fluid showed elevated levels of preformed IL-1β and TNF-α, whereas, 21 hours after implantation IL-1β, IL-6 and keratinocyte cytokine were significantly increased in the wound. Conclusions & Inferences A novel donor tissue-bone matrix trauma model was developed that is precisely adjustable and recapitulates important clinical phenomena. The non-narcotic model demonstrated that increasing tissue injury progressively caused ileus, initiated a systemic inflammatory response and developed inflammatory changes within the wound. PMID:21303433

  13. Optically switchable molecular device using microsphere based junctions

    NASA Astrophysics Data System (ADS)

    Faramarzi, V.; Raimondo, C.; Reinders, F.; Mayor, M.; Samorı, P.; Doudin, B.

    2011-12-01

    Metallic planar electrodes are bridged using microspheres coated with chemisorbed azobenzene self-assembled monolayers. The circuit exhibits light-induced switching, with reproducibility over 90%, as statistically determined and compared to junctions incorporating photo-insensitive alkanethiol layers. Microsphere interconnects provide direct access to molecular transport properties, with reliability and stability, making multifunctional molecular electronics devices possible.

  14. Metallic coating of microspheres

    SciTech Connect

    Meyer, S.F.

    1980-08-15

    Extremely smooth, uniform metal coatings of micrometer thicknesses on microscopic glass spheres (microspheres) are often needed as targets for inertial confinement fusion (ICF) experiments. The first part of this paper reviews those methods used successfully to provide metal coated microspheres for ICF targets, including magnetron sputtering, electro- and electroless plating, and chemical vapor pyrolysis. The second part of this paper discusses some of the critical aspects of magnetron sputter coating of microspheres, including substrate requirements, the sticking of microspheres during coating (preventing a uniform coating), and the difficulties in growing the desired dense, smooth, uniform microstructure on continuously moving spherical substrates.

  15. Mineralization, biodegradation, and drug release behavior of gelatin/apatite composite microspheres for bone regeneration.

    PubMed

    Leeuwenburgh, Sander C G; Jo, Junichiro; Wang, Huanan; Yamamoto, Masaya; Jansen, John A; Tabata, Yasuhiko

    2010-10-11

    Gelatin microspheres are well-known for their capacity to release growth factors in a controlled manner, but gelatin microspheres do not calcify in the absence of so-called bioactive substances that induce deposition of calcium phosphate (CaP) bone mineral. This study has investigated if CaP nanocrystals can be incorporated into gelatin microspheres to render these inert microspheres bioactive without compromising the drug releasing properties of gelatin microspheres. Incorporation of CaP nanocrystals into gelatin microspheres resulted into reduced biodegradation and drug release rates, whereas their calcifying capacity increased strongly compared to inert gelatin microspheres. The reduced drug release rate was correlated to the reduced degradation rate as caused by a physical cross-linking effect of CaP nanocrystals dispersed in the gelatin matrix. Consequently, these composite microspheres combine beneficial drug-releasing properties of organic gelatin with the calcifying capacity of a dispersed CaP phase. PMID:20804200

  16. Effect of trimebutine maleate on bethanechol-induced contractions of gastrointestinal tract in conscious and anaesthetized dogs.

    PubMed

    Yamada, K; Iizuka, M; Takaiti, O

    1983-04-01

    The effect of trimebutine maleate (TM-906) on bethanechol-induced contractions of the gastrointestinal tract in dogs was studied by means of chronically implanted force transducers, and it was compared with that of metoclopramide and atropine. During the period of motor quiescence in the fasted state of conscious dog, a bolus i.v. injection of 10 to 50 micrograms/kg bethanechol caused rhythmic contractions in the stomach and small intestine, in which an increase in basal tone was often accompanied in the distal ileum. The stomach responded to a less extent than the small intestine. Intravenous infusion of TM-906 at 3.0 mg/kg-hr for 20 to 60 min reduced the gastric contractions induced by 20 to 30 micrograms/kg bethanechol in five out of six conscious animals examined. The drug, however, enhanced the contractions of the duodenum and jejunum in a majority of the animals. Metoclopramide (1.8 mg/kg-hr) showed a tendency to potentiate the bethanechol-induced contractions in the stomach and small intestine, and atropine (0.06 mg/kg-hr) diminished them. In pentobarbital-Na anaesthetized dogs, effects of TM-906 on bethanechol-induced contractions resembled those in conscious dogs, inhibition in the stomach and potentiation in the small intestine. PMID:6136618

  17. Endoscopic detection of early malignancies in the upper gastrointestinal tract using laser-induced fluorescence imaging

    NASA Astrophysics Data System (ADS)

    Sukowski, Uwe; Ebert, Bernd; Ortner, Marianne; Zumbusch, Katharina; Mueller, Karsten; Fleige, Barbara; Lochs, Herbert; Rinneberg, Herbert H.

    2001-01-01

    Fluorescence images were recorded simultaneously with white light images to detect dyspasia or early malignancies during regular endoscopy of the upper gastrointestinal tract, after topical administration of 5-aminolaevulinic acid. Biopsies were taken at locations where fluorescence intensity were high compared with the mean fluorescence intensity of the image. Prompt and delayed fluorescence spectra of biopsies were subsequently recorded ex vivo, and normalized fluorescence intensities of Protoporphyrin IX derived from these spectra were compared with routine histology. In contrast to routine endoscopy, one early carcinoma and one signet-ring carcinoma were found in the stomach, and malignancies in a duodenal polyp. In addition, intestinal metaplasia could be visualized in the stomach of two patients, which had not been detected in biopsies taken prior to fluorescence endoscopy.

  18. Novel Regenerative Peptide TP508 Mitigates Radiation-Induced Gastrointestinal Damage By Activating Stem Cells and Preserving Crypt Integrity

    PubMed Central

    Kantara, Carla; Moya, Stephanie M.; Houchen, Courtney W.; Umar, Shahid; Ullrich, Robert L.; Singh, Pomila; Carney, Darrell H.

    2015-01-01

    In recent years, increasing threats of radiation exposure and nuclear disasters have become a significant concern for the United States and countries worldwide. Exposure to high doses of radiation triggers a number of potentially lethal effects. Among the most severe is the gastrointestinal (GI) toxicity syndrome caused by the destruction of the intestinal barrier, resulting in bacterial translocation, systemic bacteremia, sepsis and death. The lack of effective radioprotective agents capable of mitigating radiation-induced damage has prompted a search for novel countermeasures that can mitigate the effects of radiation post-exposure, accelerate tissue repair in radiation-exposed individuals, and prevent mortality. We report that a single injection of regenerative peptide TP508 (rusalatide acetate, Chrysalin®) 24h after lethal radiation exposure (9Gy, LD100/15) appears to significantly increase survival and delay mortality by mitigating radiation-induced intestinal and colonic toxicity. TP508 treatment post-exposure prevents the disintegration of gastrointestinal crypts, stimulates the expression of adherens junction protein E-cadherin, activates crypt cell proliferation, and decreases apoptosis. TP508 post-exposure treatment also up-regulates the expression of DCLK1 and LGR5 markers of stem cells that have been shown to be responsible for maintaining and regenerating intestinal crypts. Thus, TP508 appears to mitigate the effects of GI toxicity by activating radioresistant stem cells and increasing the stemness potential of crypts to maintain and restore intestinal integrity. These results suggest that TP508 may be an effective emergency nuclear countermeasure that could be delivered within 24h post-exposure to increase survival and delay mortality, giving victims time to reach clinical sites for advanced medical treatment. PMID:26280221

  19. Evaluation of antimotility effect of Lantana camara L. var. acuelata constituents on neostigmine induced gastrointestinal transit in mice

    PubMed Central

    Sagar, Lenika; Sehgal, Rajesh; Ojha, Sudarshan

    2005-01-01

    Background Lantana camara L. (Verbenaceae), a widely growing shrub which is toxic to some animal species, has been used in the traditional medicine for treating many ailments. The purpose of the present study was to evaluate the antimotility effects of Lantana camara leaf constituents in mice intestine. Methods Evaluation of antimotility activity was done in intestine of mice treated with Lantana camara leaf powder, Lantana camara methanolic extract (LCME), lantadene A, neostigmine and neostigmine + LCME. Neostigmine was used as a promotility agent. Intestinal motility was assessed by charcoal meal test and gastrointestinal transit rate was expressed as the percentage of the distance traversed by the charcoal divided by the total length of the small intestine. The antidiarrheal effect of LCME was studied against castor oil induced diarrhea model in mice. Results The intestinal transit with LCME at a dose of 500 mg/kg was 26.46% whereas the higher dose (1 g/kg) completely inhibited the transit of charcoal in normal mice. The % intestinal transit in the neostigmine pretreated groups was 24 and 11 at the same doses respectively. When the plant extracts at 125 and 250 mg/kg doses were administered intraperitonealy, there was significant reduction in fecal output compared with castor oil treated mice. At higher doses (500 and 1000 mg/kg), the fecal output was almost completely stopped. Conclusion The remarkable antimotility effect of Lantana camara methanolic extract against neostigmine as promotility agent points towards an anticholinergic effect due to Lantana camara constituents and attests to its possible utility in secretory and functional diarrheas and other gastrointestinal disorders. This effect was further confirmed by significant inhibition of castor oil induced diarrhea in mice by various doses of LCME. PMID:16168064

  20. Gastrointestinal fistula

    MedlinePlus

    Entero-enteral fistula; Enterocutaneous fistula; Fistula - gastrointestinal ... cause diarrhea , malabsorption of nutrients, and dehydration . Entero-enteral fistulas may have no symptoms. Enterocutaneous fistulas cause ...

  1. Production of hollow aerogel microspheres

    SciTech Connect

    Upadhye, R.S.; Henning, S.A.

    1990-12-31

    A method is described for making hollow aerogel microspheres of 800--1200{mu} diameter and 100--300{mu} wall thickness by forming hollow alcogel microspheres during the sol/gel process in a catalytic atmosphere and capturing them on a foam surface containing catalyst. Supercritical drying of the formed hollow alcogel microspheres yields hollow aerogel microspheres which are suitable for ICF targets.

  2. Production of hollow aerogel microspheres

    DOEpatents

    Upadhye, Ravindra S.; Henning, Sten A.

    1993-01-01

    A method is described for making hollow aerogel microspheres of 800-1200 .mu. diameter and 100-300 .mu. wall thickness by forming hollow alcogel microspheres during the sol/gel process in a catalytic atmosphere and capturing them on a foam surface containing catalyst. Supercritical drying of the formed hollow alcogel microspheres yields hollow aerogel microspheres which are suitable for ICF targets.

  3. Metabolism of proteinoid microspheres

    NASA Technical Reports Server (NTRS)

    Nakashima, T.; Fox, S. W. (Principal Investigator)

    1987-01-01

    The literature of metabolism in proteinoids and proteinoid microspheres is reviewed and criticized from a biochemical and experimental point of view. Closely related literature is also reviewed in order to understand the function of proteinoids and proteinoid microspheres. Proteinoids or proteinoid microspheres have many activities. Esterolysis, decarboxylation, amination, deamination, and oxidoreduction are catabolic enzyme activities. The formation of ATP, peptides or oligonucleotides is synthetic enzyme activities. Additional activities are hormonal and inhibitory. Selective formation of peptides is an activity of nucleoproteinoid microspheres; these are a model for ribosomes. Mechanisms of peptide and oligonucleotide syntheses from amino acids and nucleotide triphosphate by proteinoid microspheres are tentatively proposed as an integrative consequence of reviewing the literature.

  4. Metabolism of proteinoid microspheres

    NASA Technical Reports Server (NTRS)

    Nakashima, T.; Fox, S. W. (Principal Investigator)

    1987-01-01

    The literature of metabolism in proteinoids and proteinoid microspheres is reviewed and criticized from a biochemical and experimental point of view. Closely related literature is also reviewed in order to understand the function of proteinoids and proteinoid microspheres. Proteinoids or proteinoid microspheres have many activities. Esterolyis, decarboxylation, amination, deamination, and oxidoreduction are catabolic enzyme activities. The formation of ATP, peptides or oligonucleotides is synthetic enzyme activities. Additional activities are hormonal and inhibitory. Selective formation of peptides is an activity of nucleoproteinoid microspheres; these are a model for ribosomes. Mechanisms of peptide and oligonucleotide syntheses from amino acids and nucleotide triphosphate by proteinoid microspheres are tentatively proposed as an integrative consequence of reviewing the literature.

  5. Extract of green tea leaves partially attenuates streptozotocin-induced changes in antioxidant status and gastrointestinal functioning in rats.

    PubMed

    Juśkiewicz, Jerzy; Zduńczyk, Zenon; Jurgoński, Adam; Brzuzan, Łucja; Godycka-Kłos, Irena; Zary-Sikorska, Ewa

    2008-05-01

    Rats with severe streptozotocin (STZ)-induced diabetes were subjected to dietary green tea extract supplementation at 2 doses (0.01% and 0.2%; GTL and GTH groups, respectively) to evaluate their effects on antioxidant, gastrointestinal, and renal parameters of experimental animals. The lower dietary supplementation reflects daily consumption of 3 cups of green tea for an average adult weighing 70 kg. Supplementation of a diet with green tea extract had no influence on elevated food intake, body weight loss, increased glucose concentration, or declined antioxidant capacity of water-soluble substances in plasma in the diabetic rats. In cases of intestinal maltase activity, attenuation of liver and kidney hypertrophy, triacylglycerol concentration, and aspartate aminotransferase activity in the serum, both dietary treatments normalized metabolic disorders caused by STZ injection to a similar extent. Unlike the GTL group, the GTH treatment significantly ameliorated development of diabetes-induced abnormal values for small intestinal saccharase and lactase activities, renal microalbuminuria, thiobarbituric acid-reactive substance content in kidney tissue, as well as total antioxidant status in the serum of rats. The GTH group was also characterized by higher antioxidant capacity of lipid-soluble substances in plasma and superoxide dismutase activity in the serum. Although the higher dose of green tea extract did not completely protect against STZ-induced hyperglycemia and oxidative stress in experimental rats, this study suggests that green tea extract ingested at high amounts may prove to be a useful therapeutic option in the reversal of diabetic dysfunction. PMID:19083430

  6. A dendritic cell targeted vaccine induces long-term HIV-specific immunity within the gastrointestinal tract.

    PubMed

    Ruane, D; Do, Y; Brane, L; Garg, A; Bozzacco, L; Kraus, T; Caskey, M; Salazar, A; Trumpheller, C; Mehandru, S

    2016-09-01

    Despite significant therapeutic advances for HIV-1 infected individuals, a preventative HIV-1 vaccine remains elusive. Studies focusing on early transmission events, including the observation that there is a profound loss of gastrointestinal (GI) CD4(+) T cells during acute HIV-1 infection, highlight the importance of inducing HIV-specific immunity within the gut. Here we report on the generation of cellular and humoral immune responses in the intestines by a mucosally administered, dendritic cell (DC) targeted vaccine. Our results show that nasally delivered α-CD205-p24 vaccine in combination with polyICLC, induced polyfunctional immune responses within naso-pulmonary lymphoid sites that disseminated widely to systemic and mucosal (GI tract and the vaginal epithelium) sites. Qualitatively, while α-CD205-p24 prime-boost immunization generated CD4(+) T-cell responses, heterologous prime-boost immunization with α-CD205-p24 and NYVAC gag-p24 generated high levels of HIV-specific CD4(+) and CD8(+) T cells within the GI tract. Finally, DC-targeting enhanced the amplitude and longevity of vaccine-induced immune responses in the GI tract. This is the first report of a nasally delivered, DC-targeted vaccine to generate HIV-specific immune responses in the GI tract and will potentially inform the design of preventative approaches against HIV-1 and other mucosal infections. PMID:26732678

  7. Computational dynamics of acoustically driven microsphere systems

    NASA Astrophysics Data System (ADS)

    Glosser, Connor; Piermarocchi, Carlo; Li, Jie; Dault, Dan; Shanker, B.

    2016-01-01

    We propose a computational framework for the self-consistent dynamics of a microsphere system driven by a pulsed acoustic field in an ideal fluid. Our framework combines a molecular dynamics integrator describing the dynamics of the microsphere system with a time-dependent integral equation solver for the acoustic field that makes use of fields represented as surface expansions in spherical harmonic basis functions. The presented approach allows us to describe the interparticle interaction induced by the field as well as the dynamics of trapping in counter-propagating acoustic pulses. The integral equation formulation leads to equations of motion for the microspheres describing the effect of nondissipative drag forces. We show (1) that the field-induced interactions between the microspheres give rise to effective dipolar interactions, with effective dipoles defined by their velocities and (2) that the dominant effect of an ultrasound pulse through a cloud of microspheres gives rise mainly to a translation of the system, though we also observe both expansion and contraction of the cloud determined by the initial system geometry.

  8. Computational dynamics of acoustically driven microsphere systems.

    PubMed

    Glosser, Connor; Piermarocchi, Carlo; Li, Jie; Dault, Dan; Shanker, B

    2016-01-01

    We propose a computational framework for the self-consistent dynamics of a microsphere system driven by a pulsed acoustic field in an ideal fluid. Our framework combines a molecular dynamics integrator describing the dynamics of the microsphere system with a time-dependent integral equation solver for the acoustic field that makes use of fields represented as surface expansions in spherical harmonic basis functions. The presented approach allows us to describe the interparticle interaction induced by the field as well as the dynamics of trapping in counter-propagating acoustic pulses. The integral equation formulation leads to equations of motion for the microspheres describing the effect of nondissipative drag forces. We show (1) that the field-induced interactions between the microspheres give rise to effective dipolar interactions, with effective dipoles defined by their velocities and (2) that the dominant effect of an ultrasound pulse through a cloud of microspheres gives rise mainly to a translation of the system, though we also observe both expansion and contraction of the cloud determined by the initial system geometry. PMID:26871188

  9. Citric Acid Induced Synthesis of a Series of Morphology-Controllable Ag Microspheres and Their Surface-Enhanced Raman Scattering

    NASA Astrophysics Data System (ADS)

    Hu, J.; Wang, F.; Li, Y.; Li, Q.

    2015-11-01

    A facile route has been used to synthesize a series of morphology-controllable 3D hierarchical Ag microspheres (AgMS) by using citric acid as a morphology directing-reagent. The AgMS are self-assembled by Ag nanosheets which can be controlled, including the thickness of the nanosheets and the distance between two nanosheets by varying the concentration of citric acid. The average thickness of the Ag nanosheets decreased from ~107 to ~22 nm with increasing citric acid concentration. The distance between two of Ag nanosheets is at a range of 15 to 35 nm. The SERS activity of the products has been investigated in detail by using rhodamine 6G (R6G). The results show that R6G can be detected in a concentration as low as 10-7 M. The appropriate interstitial sites of interlaced Ag nanosheets assembled on AgMS provide "hot spots" which result in a strong SERS response, and the electromagnetic enhancement may play the main role in SERS. The SERS activity of a sample has been studied by using melamine, and the limit of detection is found to be 0.6 ppm.

  10. In situ growth of copper nanocrystals from carbonaceous microspheres with electrochemical glucose sensing properties

    SciTech Connect

    Zhou, Xiaoliang; Yan, Zhengguang Han, Xiaodong

    2014-02-01

    Graphical abstract: In situ growth of copper nanoparticles from hydrothermal copper-containing carbonaceous microspheres was induced by annealing or electron beam irradiation. Obtained micro-nano carbon/copper composite microspheres show electrochemical glucose sensing properties. - Highlights: • We synthesized carbonaceous microspheres containing non-nanoparicle copper species through a hydrothermal route. • By annealing or electron beam irradiation, copper nanoparticles would form from the carbonaceous microspheres in situ. • By controlling the annealing temperature, particle size of copper could be controlled in the range of 50–500 nm. • The annealed carbon/copper hierarchical composite microspheres were used to fabricate an electrochemical glucose sensor. - Abstract: In situ growth of copper nanocrystals from carbon/copper microspheres was observed in a well-controlled annealing or an electron beam irradiation process. Carbonaceous microspheres containing copper species with a smooth appearance were yielded by a hydrothermal synthesis using copper nitrate and ascorbic acid as reactants. When annealing the carbonaceous microspheres under inert atmosphere, copper nanoparticles were formed on carbon microspheres and the copper particle sizes can be increased to a range of 50–500 nm by altering the heating temperature. Similarly, in situ formation of copper nanocrystals from these carbonaceous microspheres was observed on the hydrothermal product carbonaceous microspheres with electron beam irradiation in a vacuum transmission electron microscopy chamber. The carbon/copper composite microspheres obtained through annealing were used to modify a glassy carbon electrode and tested as an electrochemical glucose sensor.

  11. Diet-Induced Regulation of Bitter Taste Receptor Subtypes in the Mouse Gastrointestinal Tract

    PubMed Central

    Vegezzi, Gaia; Anselmi, Laura; Huynh, Jennifer; Barocelli, Elisabetta; Rozengurt, Enrique; Raybould, Helen; Sternini, Catia

    2014-01-01

    Bitter taste receptors and signaling molecules, which detect bitter taste in the mouth, are expressed in the gut mucosa. In this study, we tested whether two distinct bitter taste receptors, the bitter taste receptor 138 (T2R138), selectively activated by isothiocyanates, and the broadly tuned bitter taste receptor 108 (T2R108) are regulated by luminal content. Quantitative RT-PCR analysis showed that T2R138 transcript is more abundant in the colon than the small intestine and lowest in the stomach, whereas T2R108 mRNA is more abundant in the stomach compared to the intestine. Both transcripts in the stomach were markedly reduced by fasting and restored to normal levels after 4 hours re-feeding. A cholesterol-lowering diet, mimicking a diet naturally low in cholesterol and rich in bitter substances, increased T2R138 transcript, but not T2R108, in duodenum and jejunum, and not in ileum and colon. Long-term ingestion of high-fat diet increased T2R138 RNA, but not T2R108, in the colon. Similarly, α-gustducin, a bitter taste receptor signaling molecule, was reduced by fasting in the stomach and increased by lowering cholesterol in the small intestine and by high-fat diet in the colon. These data show that both short and long term changes in the luminal contents alter expression of bitter taste receptors and associated signaling molecules in the mucosa, supporting the proposed role of bitter taste receptors in luminal chemosensing in the gastrointestinal tract. Bitter taste receptors might serve as regulatory and defensive mechanism to control gut function and food intake and protect the body from the luminal environment. PMID:25238152

  12. Microsphere Insulation Panels

    NASA Technical Reports Server (NTRS)

    Mohling, R.; Allen, M.; Baumgartner, R.

    2006-01-01

    Microsphere insulation panels (MIPs) have been developed as lightweight, longlasting replacements for the foam and vacuum-jacketed systems heretofore used for thermally insulating cryogenic vessels and transfer ducts. The microsphere core material of a typical MIP consists of hollow glass bubbles, which have a combination of advantageous mechanical, chemical, and thermal-insulation properties heretofore available only separately in different materials. In particular, a core filling of glass microspheres has high crush strength and low density, is noncombustible, and performs well in soft vacuum.

  13. Efficacy of thiolated eudragit microspheres as an oral vaccine delivery system to induce mucosal immunity against enterotoxigenic Escherichia coli in mice.

    PubMed

    Lee, Won-Jung; Cha, Seungbin; Shin, Minkyoung; Jung, Myunghwan; Islam, Mohammad Ariful; Cho, Chong-su; Yoo, Han Sang

    2012-05-01

    A vaccine delivery system based on thiolated eudragit microsphere (TEMS) was studied in vivo for its ability to elicit mucosal immunity against enterotoxigenic Escherichia coli (ETEC). Groups of mice were orally immunized with F4 or F18 fimbriae of ETEC and F4 or F18 loaded in TEMS. Mice that were orally administered with F4 or F18 loaded TEMS showed higher antigen-specific IgG antibody responses in serum and antigen-specific IgA in saliva and feces than mice that were immunized with antigens only. In addition, oral vaccination of F4 or F18 loaded TEMS resulted in higher numbers of IgG and IgA antigen-specific antibody secreting cells in the spleen, lamina propria, and Peyer's patches of immunized mice than other groups. Moreover, TEMS administration loaded with F4 or F18 induced mixed Th1 and Th2 type responses based on similarly increased levels of IgG1 and IgG2a. These results suggest that F4 or F18 loaded TEMS may be a promising candidate for an oral vaccine delivery system to elicit systemic and mucosal immunity against ETEC. PMID:22306699

  14. Treatment of Staphylococcus aureus-induced chronic osteomyelitis with bone-like hydroxyapatite/poly amino acid loaded with rifapentine microspheres

    PubMed Central

    Yan, Ling; Jiang, Dian-Ming; Cao, Zhi-Dong; Wu, Jun; Wang, Xin; Wang, Zheng-Long; Li, Ya-Jun; Yi, Yong-Fen

    2015-01-01

    Purpose The purpose of this study was to investigate the curative effect of bone-like hydroxyapatite/poly amino acid (BHA/PAA) as a carrier for poly(lactic-co-glycolic acid)-coated rifapentine microsphere (RPM) in the treatment of rabbit chronic osteomyelitis induced by Staphylococcus aureus. Methods RPM was prepared through an oil-in-water emulsion solvent evaporation method, and RPM was combined with BHA/PAA to obtain drug-loaded, slow-releasing materials. Twenty-six New Zealand white rabbits were induced to establish the animal model of chronic osteomyelitis. After debridement, the animals were randomly divided into three groups (n=8): the experimental group (with RPM-loaded BHA/PAA), the control group (with BHA/PAA), and the blank group. The RPM-loaded BHA/PAA was evaluated for antibacterial activity, dynamics of drug release, and osteogenic ability through in vitro and in vivo experiments. Results In vitro, RPM-loaded BHA/PAA released the antibiotics slowly, inhibiting the bacterial growth of S. aureus for up to 5 weeks. In vivo, at week 4, the bacterial colony count was significantly lower in the experimental group than in the control and blank groups (P<0.01). At week 12, the chronic osteomyelitis was cured and the bone defect was repaired in the experimental group, whereas the infection and bone defect persisted in the control and blank groups. Conclusion In vitro and in vivo experiments demonstrated that RPM-loaded BHA/PAA effectively cured S. aureus-induced chronic osteomyelitis. Therefore, BHA/PAA has potential value as a slow-releasing material in clinical setting. Further investigation is needed to determine the optimal dosage for loading rifapentine. PMID:26213463

  15. Surface Wrinkling on Polydimethylsiloxane Microspheres via Wet Surface Chemical Oxidation

    PubMed Central

    Yin, Jian; Han, Xue; Cao, Yanping; Lu, Conghua

    2014-01-01

    Here we introduce a simple low-cost yet robust method to realize spontaneously wrinkled morphologies on spherical surfaces. It is based on surface chemical oxidation of aqueous-phase-synthesized polydimethylsiloxane (PDMS) microspheres in the mixed H2SO4/HNO3/H2O solution. Consequently, curvature and overstress-sensitive wrinkles including dimples and labyrinth patterns are successfully induced on the resulting oxidized PDMS microspheres. A power-law dependence of the wrinkling wavelength on the microsphere radius exists. The effects of experimental parameters on these tunable spherical wrinkles have been systematically investigated, when the microspheres are pre-deposited on a substrate. These parameters include the radius and modulus of microspheres, the mixed acid solution composition, the oxidation duration, and the water washing post-treatment. Meanwhile, the complicated chemical oxidation process has also been well studied by in-situ optical observation via the microsphere system, which represents an intractable issue in a planar system. Furthermore, we realize surface wrinkled topographies on the whole microspheres at a large scale, when microspheres are directly dispersed in the mixed acid solution for surface oxidation. These results indicate that the introduced wet surface chemical oxidation has the great potential to apply to other complicated curved surfaces for large-scale generation of well-defined wrinkling patterns, which endow the solids with desired physical properties. PMID:25028198

  16. Identification of a common oncofoetal protein in x-ray and chemically induced rat gastrointestinal tumours.

    PubMed Central

    Stevens, R. H.; Cole, D. A.; Cheng, H. F.

    1981-01-01

    An apparently unique circulating common oncofoetal protein has been identified in rat small-bowel, colonic and pancreatic adenocarcinomas. The tumours were induced by ionizing radiation (small bowel), an alkyl hydrocarbon, 1,2-dimethylhydrazine (colon) and a polyaromatic hydrocarbon, 7,12-dimethylbenz[a]anthracene (pancreas). The oncofoetal protein was identified by the use of specific xenogenic antitumour rabbit sera generated to the X-ray-induced neoplasm. In addition, the foetal protein was also found always to occur in the liver and lungs of those animals bearing the chemically induced tumours as well as in their serum. These results suggest the existence of a close relationship at the molecular level in the tumorigenic processes, even though induction is by apparently different mechanisms, for cancers arising in tissue or common embryonic origin. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 PMID:6788060

  17. Biologically erodable microspheres as potential oral drug delivery systems

    NASA Astrophysics Data System (ADS)

    Mathiowitz, Edith; Jacob, Jules S.; Jong, Yong S.; Carino, Gerardo P.; Chickering, Donald E.; Chaturvedi, Pravin; Santos, Camilla A.; Vijayaraghavan, Kavita; Montgomery, Sean; Bassett, Michael; Morrell, Craig

    1997-03-01

    Biologically adhesive delivery systems offer important advantages1-5 over conventional drug delivery systems6. Here we show that engineered polymer microspheres made of biologically erodable polymers, which display strong adhesive interactions with gastrointestinal mucus and cellular linings, can traverse both the mucosal absorptive epithelium and the follicle-associated epithelium covering the lymphoid tissue of Peyer's patches. The polymers maintain contact with intestinal epithelium for extended periods of time and actually penetrate it, through and between cells. Thus, once loaded with compounds of pharmacological interest, the microspheres could be developed as delivery systems to transfer biologically active molecules to the circulation. We show that these microspheres increase the absorption of three model substances of widely different molecular size: dicumarol, insulin and plasmid DNA.

  18. Organic aerogel microspheres

    DOEpatents

    Mayer, Steven T.; Kong, Fung-Ming; Pekala, Richard W.; Kaschmitter, James L.

    1999-01-01

    Organic aerogel microspheres which can be used in capacitors, batteries, thermal insulation, adsorption/filtration media, and chromatographic packings, having diameters ranging from about 1 micron to about 3 mm. The microspheres can be pyrolyzed to form carbon aerogel microspheres. This method involves stirring the aqueous organic phase in mineral oil at elevated temperature until the dispersed organic phase polymerizes and forms nonsticky gel spheres. The size of the microspheres depends on the collision rate of the liquid droplets and the reaction rate of the monomers from which the aqueous solution is formed. The collision rate is governed by the volume ratio of the aqueous solution to the mineral oil and the shear rate, while the reaction rate is governed by the chemical formulation and the curing temperature.

  19. Organic aerogel microspheres

    DOEpatents

    Mayer, S.T.; Kong, F.M.; Pekala, R.W.; Kaschmitter, J.L.

    1999-06-01

    Organic aerogel microspheres are disclosed which can be used in capacitors, batteries, thermal insulation, adsorption/filtration media, and chromatographic packings, having diameters ranging from about 1 micron to about 3 mm. The microspheres can be pyrolyzed to form carbon aerogel microspheres. This method involves stirring the aqueous organic phase in mineral oil at elevated temperature until the dispersed organic phase polymerizes and forms nonstick gel spheres. The size of the microspheres depends on the collision rate of the liquid droplets and the reaction rate of the monomers from which the aqueous solution is formed. The collision rate is governed by the volume ratio of the aqueous solution to the mineral oil and the shear rate, while the reaction rate is governed by the chemical formulation and the curing temperature.

  20. Gastrointestinal Infections.

    PubMed

    Alby, Kevin; Nachamkin, Irving

    2016-06-01

    Gastrointestinal infections in the immunocompromised host are caused by the common bacterial, viral, fungal, and parasitic agents that also cause infections in the immunocompetent host. Of special consideration is that immunocompromised patients may be at increased risk for infection or disease severity and by pathogens not seen in the competent host. This chapter reviews the various agents, risk factors, and diagnostic approaches to detect gastrointestinal infections in this patient population. PMID:27337464

  1. [Gastrointestinal bleeding].

    PubMed

    Lanas, Ángel

    2015-09-01

    In the Digestive Disease Week in 2015 there have been some new contributions in the field of gastrointestinal bleeding that deserve to be highlighted. Treatment of celecoxib with a proton pump inhibitor is safer than treatment with nonselective NSAID and a proton pump inhibitor in high risk gastrointestinal and cardiovascular patients who mostly also take acetylsalicylic acid. Several studies confirm the need to restart the antiplatelet or anticoagulant therapy at an early stage after a gastrointestinal hemorrhage. The need for urgent endoscopy before 6-12 h after the onset of upper gastrointestinal bleeding episode may be beneficial in patients with hemodynamic instability and high risk for comorbidity. It is confirmed that in Western but not in Japanese populations, gastrointestinal bleeding episodes admitted to hospital during weekend days are associated with a worse prognosis associated with delays in the clinical management of the events. The strategy of a restrictive policy on blood transfusions during an upper GI bleeding event has been challenged. Several studies have shown the benefit of identifying the bleeding vessel in non varicose underlying gastric lesions by Doppler ultrasound which allows direct endoscopic therapy in the patient with upper GI bleeding. Finally, it has been reported that lower gastrointestinal bleeding diverticula band ligation or hemoclipping are both safe and have the same long-term outcomes. PMID:26520197

  2. HIF-1α and HIF-2α induced angiogenesis in gastrointestinal vascular malformation and reversed by thalidomide.

    PubMed

    Feng, Nan; Chen, Haiying; Fu, Sengwang; Bian, Zhaolian; Lin, Xiaolu; Yang, Li; Gao, Yunjie; Fang, Jingyuan; Ge, Zhizheng

    2016-01-01

    Thalidomide is used in clinical practice to treat gastrointestinal vascular malformation (GIVM), but the pathogenesis of GIVM is not clear. Hypoxia inducible factor 1 alpha (HIF-1α) and 2 alpha (HIF-2α/EPAS1) are in the same family and act as master regulators of the adaptive response to hypoxia. HIF-1α and HIF-2α are up-regulated in vascular malformations in intestinal tissues from GIVM patients, but not in adjacent normal vessels. Therefore, we investigated the role of HIF-1α and HIF-2α during angiogenesis and the mechanism of thalidomide action. In vitro experiments confirmed that vascular endothelial growth factor (VEGF) was a direct target of HIF-2α and that HIF-1α and HIF-2α regulated NOTCH1, Ang2, and DLL4, which enhanced vessel-forming of endothelial cells. Thalidomide down-regulated the expression of HIF-1α and HIF-2α and inhibited angiogenesis. In vivo zebrafish experiments suggested that HIF-2α overexpression was associated with abnormal subintestinal vascular (SIV) sprouting, which was reversed by thalidomide. This result indicated that thalidomide regulated angiogenesis via the inhibition of HIF-1α and HIF-2α expression, which further regulated downstream factors, including VEGF, NOTCH1, DLL4, and Ang2. The abnormally high expression of HIF-1α and HIF-2α may contribute to GIVM. PMID:27249651

  3. HIF-1α and HIF-2α induced angiogenesis in gastrointestinal vascular malformation and reversed by thalidomide

    PubMed Central

    Feng, Nan; Chen, Haiying; Fu, Sengwang; Bian, Zhaolian; Lin, Xiaolu; Yang, Li; Gao, Yunjie; Fang, Jingyuan; Ge, Zhizheng

    2016-01-01

    Thalidomide is used in clinical practice to treat gastrointestinal vascular malformation (GIVM), but the pathogenesis of GIVM is not clear. Hypoxia inducible factor 1 alpha (HIF-1α) and 2 alpha (HIF-2α/EPAS1) are in the same family and act as master regulators of the adaptive response to hypoxia. HIF-1α and HIF-2α are up-regulated in vascular malformations in intestinal tissues from GIVM patients, but not in adjacent normal vessels. Therefore, we investigated the role of HIF-1α and HIF-2α during angiogenesis and the mechanism of thalidomide action. In vitro experiments confirmed that vascular endothelial growth factor (VEGF) was a direct target of HIF-2α and that HIF-1α and HIF-2α regulated NOTCH1, Ang2, and DLL4, which enhanced vessel-forming of endothelial cells. Thalidomide down-regulated the expression of HIF-1α and HIF-2α and inhibited angiogenesis. In vivo zebrafish experiments suggested that HIF-2α overexpression was associated with abnormal subintestinal vascular (SIV) sprouting, which was reversed by thalidomide. This result indicated that thalidomide regulated angiogenesis via the inhibition of HIF-1α and HIF-2α expression, which further regulated downstream factors, including VEGF, NOTCH1, DLL4, and Ang2. The abnormally high expression of HIF-1α and HIF-2α may contribute to GIVM. PMID:27249651

  4. Irinotecan-Induced Gastrointestinal Dysfunction and Pain Are Mediated by Common TLR4-Dependent Mechanisms.

    PubMed

    Wardill, Hannah R; Gibson, Rachel J; Van Sebille, Ysabella Z A; Secombe, Kate R; Coller, Janet K; White, Imogen A; Manavis, Jim; Hutchinson, Mark R; Staikopoulos, Vasiliki; Logan, Richard M; Bowen, Joanne M

    2016-06-01

    Strong epidemiological data indicate that chemotherapy-induced gut toxicity and pain occur in parallel, indicating common underlying mechanisms. We have recently outlined evidence suggesting that TLR4 signaling may contribute to both side effects. We therefore aimed to determine if genetic deletion of TLR4 improves chemotherapy-induced gut toxicity and pain. Forty-two female wild-type (WT) and 42 Tlr4 null (-/-) BALB/c mice weighing between 18 and 25 g (10-13 weeks) received a single 270 mg/kg (i.p.) dose of irinotecan hydrochloride or vehicle control and were killed at 6, 24, 48, 72, and 96 hours. Bacterial sequencing was conducted on cecal samples of control animals to determine the gut microbiome profile. Gut toxicity was assessed using validated clinical and histopathologic markers, permeability assays, and inflammatory markers. Chemotherapy-induced pain was assessed using the validated rodent facial grimace criteria, as well as immunologic markers of glial activation in the lumbar spinal cord. TLR4 deletion attenuated irinotecan-induced gut toxicity, with improvements in weight loss (P = 0.0003) and diarrhea (P < 0.0001). Crypt apoptosis was significantly decreased in BALB/c-Tlr4(-/-billy) mice (P < 0.0001), correlating with lower mucosal injury scores (P < 0.005). Intestinal permeability to FITC-dextran (4 kDa) and LPS translocation was greater in WT mice than in BALB/c-Tlr4(-/-billy) (P = 0.01 and P < 0.0001, respectively). GFAP staining in the lumbar spinal cord, indicative of astrocytic activation, was increased at 6 and 72 hours in WT mice compared with BALB/c-Tlr4(-/-billy) mice (P = 0.008, P = 0.01). These data indicate that TLR4 is uniquely positioned to mediate irinotecan-induced gut toxicity and pain, highlighting the possibility of a targetable gut/CNS axis for improved toxicity outcomes. Mol Cancer Ther; 15(6); 1376-86. ©2016 AACR. PMID:27197307

  5. POROUS WALL, HOLLOW GLASS MICROSPHERES

    SciTech Connect

    Sexton, W.

    2012-06-30

    magnitude, which can result in unique properties in areas such as hydrogen storage, gas transport, gas separations and purifications, sensors, global warming applications, new drug delivery systems and so on. One of the most interesting porous glass products that SRNL has developed and patented is Porous Wall, Hollow Glass Microspheres (PW-HGMs) that are being studied for many different applications. The European Patent Office (EPO) just recently notified SRS that the continuation-in-part patent application for the PW-HGMs has been accepted. The original patent, which was granted by the EPO on June 2, 2010, was validated in France, Germany and the United Kingdom. The microspheres produced are generally in the range of 2 to 100 microns, with a 1 to 2 micron wall. What makes the SRNL microspheres unique from all others is that the team in Figure 1 has found a way to induce and control porosity through the thin walls on a scale of 100 to 3000 {angstrom}. This is what makes the SRNL HW-HGMs one-of-a-kind, and is responsible for many of their unique properties and potential for various applications, including those in tritium storage, gas separations, H-storage for vehicles, and even a variety of new medical applications in the areas of drug delivery and MRI contrast agents. SRNL Hollow Glass Microspheres, and subsequent, Porous Wall, Hollow Glass Microspheres are fabricated using a flame former apparatus. Figure 2 is a schematic of the apparatus.

  6. A role of CB1R in inducing θ-rhythm coordination between the gustatory and gastrointestinal insula

    PubMed Central

    Kang, Youngnam; Sato, Hajime; Saito, Mitsuru; Yin, Dong Xu; Park, Sook Kyung; Oh, Seog Bae; Bae, Yong Chul; Toyoda, Hiroki

    2016-01-01

    Anandamide (AEA) and N-oleoylethanolamine (OEA) are produced in the intestine and brain during fasting and satiety, respectively. Subsequently, AEA facilitates food intake via activation of cannabinoid type-1 receptors (CB1Rs) while OEA decreases food intake via activation of peroxisome proliferator-activated receptor-α (PPARα) and/or G-protein-coupled receptor 119 (GPR119). Neuronal activity in the gastrointestinal region of the autonomic insula (GI-Au-I) that rostrally adjoins the gustatory insula (Gu-I) increases during fasting, enhancing appetite while umami and sweet taste sensations in Gu-I enhances appetite in GI-Au-I, strongly suggesting the presence of a neural interaction between the Gu-I and GI-Au-I which changes depending on the concentrations of AEA and OEA. However, this possibility has never been investigated. In rat slice preparations, we demonstrate with voltage-sensitive dye imaging that activation of CB1Rs by AEA induces θ-rhythm oscillatory synchronization in the Gu-I which propagates into the GI-Au-I but stops at its caudal end, displaying an oscillatory coordination. The AEA-induced oscillation was abolished by a CB1R antagonist or OEA through activation of GPR119. Our results demonstrate that the neural coordination between the Gu-I and GI-Au-I is generated or suppressed by the opposing activities between CB1R and GPR119. This mechanism may be involved in the feeding behavior based on taste recognition. PMID:27581068

  7. A role of CB1R in inducing θ-rhythm coordination between the gustatory and gastrointestinal insula.

    PubMed

    Kang, Youngnam; Sato, Hajime; Saito, Mitsuru; Yin, Dong Xu; Park, Sook Kyung; Oh, Seog Bae; Bae, Yong Chul; Toyoda, Hiroki

    2016-01-01

    Anandamide (AEA) and N-oleoylethanolamine (OEA) are produced in the intestine and brain during fasting and satiety, respectively. Subsequently, AEA facilitates food intake via activation of cannabinoid type-1 receptors (CB1Rs) while OEA decreases food intake via activation of peroxisome proliferator-activated receptor-α (PPARα) and/or G-protein-coupled receptor 119 (GPR119). Neuronal activity in the gastrointestinal region of the autonomic insula (GI-Au-I) that rostrally adjoins the gustatory insula (Gu-I) increases during fasting, enhancing appetite while umami and sweet taste sensations in Gu-I enhances appetite in GI-Au-I, strongly suggesting the presence of a neural interaction between the Gu-I and GI-Au-I which changes depending on the concentrations of AEA and OEA. However, this possibility has never been investigated. In rat slice preparations, we demonstrate with voltage-sensitive dye imaging that activation of CB1Rs by AEA induces θ-rhythm oscillatory synchronization in the Gu-I which propagates into the GI-Au-I but stops at its caudal end, displaying an oscillatory coordination. The AEA-induced oscillation was abolished by a CB1R antagonist or OEA through activation of GPR119. Our results demonstrate that the neural coordination between the Gu-I and GI-Au-I is generated or suppressed by the opposing activities between CB1R and GPR119. This mechanism may be involved in the feeding behavior based on taste recognition. PMID:27581068

  8. Radiotherapy combined with TLR7/8 activation induces strong immune responses against gastrointestinal tumors.

    PubMed

    Schölch, Sebastian; Rauber, Conrad; Tietz, Alexandra; Rahbari, Nuh N; Bork, Ulrich; Schmidt, Thomas; Kahlert, Christoph; Haberkorn, Uwe; Tomai, Mark A; Lipson, Kenneth E; Carretero, Rafael; Weitz, Jürgen; Koch, Moritz; Huber, Peter E

    2015-03-10

    In addition to local cytotoxic activity, radiotherapy may also elicit local and systemic antitumor immunity, which may be augmented by immunotherapeutic agents including Toll-like receptor (TLR) 7/8 agonists. Here, we investigated the ability of 3M-011 (854A), a TLR7/8 agonist, to boost the antigen-presenting activity of dendritic cells (DC) as an adjuvant to radiotherapy. The combined treatment induced marked local and systemic responses in subcutaneous and orthotopic mouse models of colorectal and pancreatic cancer. In vitro cytotoxicity assays as well as in vivo depletion experiments with monoclonal antibodies identified NK and CD8 T cells as the cell populations mediating the cytotoxic effects of the treatment, while in vivo depletion of CD11c+ dendritic cells (DC) in CD11c-DTR transgenic mice revealed DC as the pivotal immune hub in this setting. The specificity of the immune reaction was confirmed by ELISPOT assays. TLR7/8 agonists therefore seem to be potent adjuvants to radiotherapy, inducing strong local and profound systemic immune responses to tumor antigens released by conventional therapy. PMID:25609199

  9. Radiotherapy combined with TLR7/8 activation induces strong immune responses against gastrointestinal tumors

    PubMed Central

    Tietz, Alexandra; Rahbari, Nuh N.; Bork, Ulrich; Schmidt, Thomas; Kahlert, Christoph; Haberkorn, Uwe; Tomai, Mark A.; Lipson, Kenneth E.; Carretero, Rafael; Weitz, Jürgen; Koch, Moritz; Huber, Peter E.

    2015-01-01

    In addition to local cytotoxic activity, radiotherapy may also elicit local and systemic antitumor immunity, which may be augmented by immunotherapeutic agents including Toll-like receptor (TLR) 7/8 agonists. Here, we investigated the ability of 3M-011 (854A), a TLR7/8 agonist, to boost the antigen-presenting activity of dendritic cells (DC) as an adjuvant to radiotherapy. The combined treatment induced marked local and systemic responses in subcutaneous and orthotopic mouse models of colorectal and pancreatic cancer. In vitro cytotoxicity assays as well as in vivo depletion experiments with monoclonal antibodies identified NK and CD8 T cells as the cell populations mediating the cytotoxic effects of the treatment, while in vivo depletion of CD11c+ dendritic cells (DC) in CD11c-DTR transgenic mice revealed DC as the pivotal immune hub in this setting. The specificity of the immune reaction was confirmed by ELISPOT assays. TLR7/8 agonists therefore seem to be potent adjuvants to radiotherapy, inducing strong local and profound systemic immune responses to tumor antigens released by conventional therapy. PMID:25609199

  10. Method for sizing hollow microspheres

    DOEpatents

    Farnum, E.H.; Fries, R.J.

    1975-10-29

    Hollow Microspheres may be effectively sized by placing them beneath a screen stack completely immersed in an ultrasonic bath containing a liquid having a density at which the microspheres float and ultrasonically agitating the bath.

  11. Effects of oral glutamine supplementation on exercise-induced gastrointestinal permeability and tight junction protein expression.

    PubMed

    Zuhl, Micah N; Lanphere, Kathryn R; Kravitz, Len; Mermier, Christine M; Schneider, Suzanne; Dokladny, Karol; Moseley, Pope L

    2014-01-15

    The objectives of this study are threefold: 1) to assess whether 7 days of oral glutamine (GLN) supplementation reduces exercise-induced intestinal permeability; 2) whether supplementation prevents the proinflammatory response; and 3) whether these changes are associated with upregulation of the heat shock response. On separate occasions, eight human subjects participated in baseline testing and in GLN and placebo (PLA) supplementation trials, followed by a 60-min treadmill run. Intestinal permeability was higher in the PLA trial compared with baseline and GLN trials (0.0604 ± 0.047 vs. 0.0218 ± 0.008 and 0.0272 ± 0.007, respectively; P < 0.05). IκBα expression in peripheral blood mononuclear cells was higher 240 min after exercise in the GLN trial compared with the PLA trial (1.411 ± 0.523 vs. 0.9839 ± 0.343, respectively; P < 0.05). In vitro using the intestinal epithelial cell line Caco-2, we measured effects of GLN supplementation (0, 4, and 6 mM) on heat-induced (37° or 41.8°C) heat shock protein 70 (HSP70), heat shock factor-1 (HSF-1), and occludin expression. HSF-1 and HSP70 levels increased in 6 mM supplementation at 41°C compared with 0 mM at 41°C (1.785 ± 0.495 vs. 0.6681 ± 0.290, and 1.973 ± 0.325 vs. 1.133 ± 0.129, respectively; P < 0.05). Occludin levels increased after 4 mM supplementation at 41°C and 6 mM at 41°C compared with 0 mM at 41°C (1.236 ± 0.219 and 1.849 ± 0.564 vs. 0.7434 ± 0.027, respectively; P < 0.001). GLN supplementation prevented exercise-induced permeability, possibly through HSF-1 activation. PMID:24285149

  12. Compounds of the upper gastrointestinal tract induce rapid and efficient excystation of Entamoeba invadens

    PubMed Central

    Mitra, Biswa Nath; Pradel, Gabriele; Frevert, Ute; Eichinger, Daniel

    2010-01-01

    The infective stage of Entamoeba parasites is an encysted form. This stage can be readily generated in vitro, which has allowed identification of stimuli that trigger the differentiation of the parasite trophozoite stage into the cyst stage. Studies of the second differentiation event, emergence of the parasite from the cyst upon infection of a host, have been hampered by the lack of an efficient means to excyst the parasite and complete the life cycle in vitro. We have determined that a combination of exposures to water, bicarbonate and bile induces rapid excystment of Entamoeba invadens cysts. The high efficiency of this method has allowed the visualization of the dynamics of the process by electron and confocal microscopy, and should permit the analysis of stage-specific gene expression and high through-put screening of inhibitory compounds. PMID:20018192

  13. Alterations in the Porcine Colon Microbiota Induced by the Gastrointestinal Nematode Trichuris suis

    PubMed Central

    Wu, Sitao; Li, Weizhong; Navarro, Karl; Couch, Robin D.; Hill, Dolores; Urban, Joseph F.

    2012-01-01

    Helminth parasites ensure their survival by regulating host immunity through mechanisms that dampen inflammation. These properties have recently been exploited therapeutically to treat human diseases. The biocomplexity of the intestinal lumen suggests that interactions between the parasite and the intestinal microbiota would also influence inflammation. In this study, we characterized the microbiota in the porcine proximal colon in response to Trichuris suis (whipworm) infection using 16S rRNA gene-based and whole-genome shotgun (WGS) sequencing. A 21-day T. suis infection in four pigs induced a significant change in the composition of the proximal colon microbiota compared to that of three parasite-naive pigs. Among the 15 phyla identified, the abundances of Proteobacteria and Deferribacteres were changed in infected pigs. The abundances of approximately 13% of genera were significantly altered by infection. Changes in relative abundances of Succinivibrio and Mucispirillum, for example, may relate to alterations in carbohydrate metabolism and niche disruptions in mucosal interfaces induced by parasitic infection, respectively. Of note, infection by T. suis led to a significant shift in the metabolic potential of the proximal colon microbiota, where 26% of all metabolic pathways identified were affected. Besides carbohydrate metabolism, lysine biosynthesis was repressed as well. A metabolomic analysis of volatile organic compounds (VOCs) in the luminal contents showed a relative absence in infected pigs of cofactors for carbohydrate and lysine biosynthesis, as well as an accumulation of oleic acid, suggesting altered fatty acid absorption contributing to local inflammation. Our findings should facilitate development of strategies for parasitic control in pigs and humans. PMID:22493085

  14. Involvement of mu-opioid receptors in antinociception and inhibition of gastrointestinal transit induced by 7-hydroxymitragynine, isolated from Thai herbal medicine Mitragyna speciosa.

    PubMed

    Matsumoto, Kenjiro; Hatori, Yoshio; Murayama, Toshihiko; Tashima, Kimihito; Wongseripipatana, Sumphan; Misawa, Kaori; Kitajima, Mariko; Takayama, Hiromitsu; Horie, Syunji

    2006-11-01

    7-hydroxymitragynine, a constituent of the Thai herbal medicine Mitragyna speciosa, has been found to have a potent opioid antinociceptive effect. In the present study, we investigated the mechanism of antinociception and the inhibitory effect on gastrointestinal transit of 7-hydroxymitragynine, and compared its effects with those of morphine. When administered subcutaneously to mice, 7-hydroxymitragynine produced antinociceptive effects about 5.7 and 4.4 times more potent than those of morphine in the tail-flick (ED50=0.80 mg/kg) and hot-plate (ED50=0.93 mg/kg) tests, respectively. The antinociceptive effect of 7-hydroxymitragynine was significantly blocked by the mu1/mu2-opioid receptor antagonist beta-funaltrexamine hydrochloride (beta-FNA) and the mu1-opioid receptor-selective antagonist naloxonazine in both tests. Thus, 7-hydroxymitragynine acts predominantly on mu-opioid receptors, especially on mu1-opioid receptors. Isolated tissue studies further supported its specificity for the mu-opioid receptors. Further, 7-hydroxymintragynine dose-dependently (ED50=1.19 mg/kg, s.c.) and significantly inhibited gastrointestinal transit in mice, as morphine does. The inhibitory effect was significantly antagonized by beta-FNA pretreatment, but slightly antagonized by naloxonazine. The ED50 value of 7-hydroxymitragynine on gastrointestinal transit was larger than its antinociceptive ED50 value. On the other hand, morphine significantly inhibits gastrointestinal transit at a much smaller dose than its antinociceptive dose. These results suggest that mu-opioid receptor mechanisms mediate the antinociceptive effect and inhibition of gastrointestinal transit. This compound induced more potent antinociceptive effects and was less constipating than morphine. PMID:16978601

  15. The inhibitory effects of alpha(2)-adrenoceptor agonists on gastrointestinal transit during croton oil-induced intestinal inflammation.

    PubMed Central

    Pol, O.; Valle, L.; Ferrer, I.; Puig, M. M.

    1996-01-01

    1. The peripheral effects of alpha(2)-adrenoceptor agonists were investigated in a model of intestinal inflammation induced by intragastric administration of croton oil (CO). Our hypothesis was that inflammation would 'sensitize' adrenoceptors in peripheral and/or central terminals of myenteric and submucous plexus neurones, and enhance systemic effects of alpha(2)-adrenoceptor agonists. 2. Male swiss CD-1 mice, received intragastrically CO (0.05 ml), castor oil (CA, 0.1 ml) or saline (SS) 3 h before the study: gastrointestinal transit (GIT) was evaluated 20 min afterwards with a charcoal meal. The presence of inflammation was assessed by electron microscopy. 3. The intragastric administration of CA or CO caused an increase in GIT and weight loss, but only CO induced an inflammatory response. Both clonidine (imidazoline1/alpha(2)-agonist) and UK-14304 (alpha(2)-agonist) produced dose-related inhibitions of GIT in all groups. During inflammatory diarrhoea (CO), potencies of systemic (s.c.) clonidine and UK-14304 were significantly increased 3.5 and 2.1 times, respectively, while potencies remained unaltered in the presence of diarrhoea without inflammation (CA). The effects were reversed by administration (s.c.) of receptor-specific adrenoceptor antagonists, but not by naloxone. 4. Clonidine was 8.3 (SS) and 2.8 (CO) times more potent when administered intracerebroventricularly (i.c.v.), than when administered s.c. Inflammation of the gut did not alter the potency of i.c.v. clonidine, demonstrating that enhanced effects of s.c. clonidine are mediated by peripheral receptors. During inflammation, i.c.v. efaroxan did not antagonize low doses of s.c. clonidine (ED20 and ED50S), but partially reversed ED80S, further supporting the peripheral effects of the agonists in CO treated animals. 5. The results demonstrate that inflammation of the gut enhances the potency of alpha(2)-adrenoceptor agonists by a peripheral mechanism. The results also suggest that the inflammatory

  16. SRNL POROUS WALL GLASS MICROSPHERES

    SciTech Connect

    Wicks, G; Leung Heung, L; Ray Schumacher, R

    2008-04-15

    The Savannah River National Laboratory (SRNL) has developed a new medium for storage of hydrogen and other gases. This involves fabrication of thin, Porous Walled, Hollow Glass Microspheres (PW-HGMs), with diameters generally in the range of 1 to several hundred microns. What is unique about the glass microballons is that porosity has been induced and controlled within the thin, one micron thick walls, on the scale of 10 to several thousand Angstroms. This porosity results in interesting properties including the ability to use these channels to fill the microballons with special absorbents and other materials, thus providing a contained environment even for reactive species. Gases can now enter the microspheres and be retained on the absorbents, resulting in solid-state and contained storage of even reactive species. Also, the porosity can be altered and controlled in various ways, and even used to filter mixed gas streams within a system. SRNL is involved in about a half dozen different programs involving these PW-HGMs and an overview of some of these activities and results emerging are presented.

  17. Method for preparing hollow metal oxide microsphere

    DOEpatents

    Schmitt, C.R.

    1974-02-12

    Hollow refractory metal oxide microspheres are prepared by impregnating resinous microspheres with a metallic compound, drying the impregnated microspheres, heating the microspheres slowly to carbonize the resin, and igniting the microspheres to remove the carbon and to produce the metal oxide. Zirconium oxide is given as an example. (Official Gazette)

  18. Uvangoletin induces mitochondria-mediated apoptosis in HL-60 cells in vitro and in vivo without adverse reactions of myelosuppression, leucopenia and gastrointestinal tract disturbances.

    PubMed

    Zheng, Zhuanzhen; Qiao, Zhenhua; Gong, Rong; Wang, Yalin; Zhang, Yiqun; Ma, Yanping; Zhang, Li; Lu, Yujin; Jiang, Bo; Li, Guoxia; Dong, Chunxia; Chen, Wenliang

    2016-02-01

    This study investigated the cytotoxic effect of uvangoletin on HL-60 cells, and the effects of uvangoletin on myelosuppression, leucopenia, gastrointestinal tract disturbances and the possible cytotoxic mechanisms by using CCK-8, flow cytometry, western blot, xenograft, cyclophosphamide-induced leucopenia, copper sulfate-induced emesis and ethanol-induced gastric mucosal lesions assays. The results of CCK-8, flow cytometry and western blot assays indicated that uvangoletin showed the cytotoxic effect on HL-60 cells and induced the apoptosis of HL-60 cells by downregulating the expression levels of anti-apoptotic proteins (Survivin, Bcl-xl and Bcl-2), upregulating the expression levels of pro-apoptotic proteins (Smac, Bax, Bad, c-caspase-3 and c-caspase-9), and promoting the release of cytochrome c from mitochondria to cytoplasm. Further, the results of xenograft assay suggested that uvangoletin inhibited the HL-60-induced tumor growth without adverse effect on body weight of nude mice in vivo by regulating the expression levels of above apoptotic proteins. The results indicated that the reductions of WBCs count and thighbone marrow granulocytes percentage in cyclophosphamide-induced leucopenia assay, the incubation period and number of emesis in copper sulfate-induced emesis assay and the gastric mucosal lesions in ethanol-induced gastric mucosal lesions assay were not exacerbated or reversed by uvangoletin. In conclusion, the research preliminarily indicated that uvangoletin induced apoptosis of HL-60 cells in vitro and in vivo without adverse reactions of myelosuppression, leucopenia and gastrointestinal tract disturbances, and the pro-apoptotic mechanisms may be related to mitochondria-mediated apoptotic pathway. PMID:26717974

  19. Wild Raspberry Subjected to Simulated Gastrointestinal Digestion Improves the Protective Capacity against Ethyl Carbamate-Induced Oxidative Damage in Caco-2 Cells

    PubMed Central

    Chen, Wei; Xu, Yang; Zhang, Lingxia; Li, Ya; Zheng, Xiaodong

    2016-01-01

    Ethyl carbamate (EC), a probable human carcinogen, occurs widely in many fermented foods. Previous studies indicated that EC-induced cytotoxicity was associated with oxidative stress. Wild raspberries are rich in polyphenolic compounds, which possess potent antioxidant activity. This study was conducted to investigate the protective effect of wild raspberry extracts produced before (RE) and after in vitro simulated gastrointestinal digestion (RD) on EC-induced oxidative damage in Caco-2 cells. Our primary data showed that ethyl carbamate could result in cytotoxicity and genotoxicity in Caco-2 cells and raspberry extract after digestion (RD) may be more effective than that before digestion (RE) in attenuating toxicity caused by ethyl carbamate. Further investigation by fluorescence microscope revealed that RD may significantly ameliorate EC-induced oxidative damage by scavenging the overproduction of intracellular reactive oxygen species (ROS), maintaining mitochondrial function and preventing glutathione (GSH) depletion. In addition, HPLC-ESI-MS results showed that the contents of identified polyphenolic compounds (esculin, kaempferol O-hexoside, and pelargonidin O-hexoside) were remarkably increased after digestion, which might be related to the better protective effect of RD. Overall, our results demonstrated that raspberry extract undergoing simulated gastrointestinal digestion may improve the protective effect against EC-induced oxidative damage in Caco-2 cells. PMID:26788245

  20. Wild Raspberry Subjected to Simulated Gastrointestinal Digestion Improves the Protective Capacity against Ethyl Carbamate-Induced Oxidative Damage in Caco-2 Cells.

    PubMed

    Chen, Wei; Xu, Yang; Zhang, Lingxia; Li, Ya; Zheng, Xiaodong

    2016-01-01

    Ethyl carbamate (EC), a probable human carcinogen, occurs widely in many fermented foods. Previous studies indicated that EC-induced cytotoxicity was associated with oxidative stress. Wild raspberries are rich in polyphenolic compounds, which possess potent antioxidant activity. This study was conducted to investigate the protective effect of wild raspberry extracts produced before (RE) and after in vitro simulated gastrointestinal digestion (RD) on EC-induced oxidative damage in Caco-2 cells. Our primary data showed that ethyl carbamate could result in cytotoxicity and genotoxicity in Caco-2 cells and raspberry extract after digestion (RD) may be more effective than that before digestion (RE) in attenuating toxicity caused by ethyl carbamate. Further investigation by fluorescence microscope revealed that RD may significantly ameliorate EC-induced oxidative damage by scavenging the overproduction of intracellular reactive oxygen species (ROS), maintaining mitochondrial function and preventing glutathione (GSH) depletion. In addition, HPLC-ESI-MS results showed that the contents of identified polyphenolic compounds (esculin, kaempferol O-hexoside, and pelargonidin O-hexoside) were remarkably increased after digestion, which might be related to the better protective effect of RD. Overall, our results demonstrated that raspberry extract undergoing simulated gastrointestinal digestion may improve the protective effect against EC-induced oxidative damage in Caco-2 cells. PMID:26788245

  1. Polyvinyl pyridine microspheres

    NASA Technical Reports Server (NTRS)

    Rembaum, Alan (Inventor); Gupta, Amitava (Inventor); Volksen, Willi (Inventor)

    1980-01-01

    Microspheres are produced by cobalt gamma radiation initiated polymerization of a dilute aqueous vinyl pyridine solution. Addition of cross-linking agent provides higher surface area beads. Addition of monomers such as hydroxyethylmethacrylate acrylamide or methacrylamide increases hydrophilic properties and surface area of the beads. High surface area catalytic supports are formed in the presence of controlled pore glass substrate.

  2. Doped zinc oxide microspheres

    DOEpatents

    Arnold, Jr., Wesley D.; Bond, Walter D.; Lauf, Robert J.

    1993-01-01

    A new composition and method of making same for a doped zinc oxide microsphere and articles made therefrom for use in an electrical surge arrestor which has increased solid content, uniform grain size and is in the form of a gel.

  3. Doped zinc oxide microspheres

    DOEpatents

    Arnold, W.D. Jr.; Bond, W.D.; Lauf, R.J.

    1993-12-14

    A new composition and method of making same for a doped zinc oxide microsphere and articles made therefrom for use in an electrical surge arrestor which has increased solid content, uniform grain size and is in the form of a gel. 4 figures.

  4. Fusion microsphere targets

    SciTech Connect

    Koo, J.C.

    1980-07-28

    It was shown that a microsphere within the structure limitations is hydrodynamically stable. To insure its perfect formation, the initial chemical compositions must have a blowing capability, more important, the resultant liquid compositions must also have sufficient surface tension and low viscosity.

  5. Microsphere insulation systems

    NASA Technical Reports Server (NTRS)

    Allen, Mark S. (Inventor); Willen, Gary S. (Inventor); Mohling, Robert A. (Inventor)

    2005-01-01

    A new insulation system is provided that contains microspheres. This insulation system can be used to provide insulated panels and clamshells, and to insulate annular spaces around objects used to transfer, store, or transport cryogens and other temperature-sensitive materials. This insulation system provides better performance with reduced maintenance than current insulation systems.

  6. Polyvinyl pyridine microspheres

    NASA Technical Reports Server (NTRS)

    Rembaum, Alan (Inventor); Gupta, Amitava (Inventor); Volksen, Willi (Inventor)

    1979-01-01

    Microspheres are produced by cobalt gamma radiation initiated polymerization of a dilute aqueous vinyl pyridine solution. Addition of cross-linking agent provides higher surface area beads. Addition of monomers such as hydroxyethylmethacrylate acrylamide or methacrylamide increases hydrophilic properties and surface area of the beads. High surface area catalytic supports are formed in the presence of controlled pore glass substrate.

  7. Evaluation of porous carrier-based floating orlistat microspheres for gastric delivery.

    PubMed

    Jain, Sunil K; Agrawal, Govind P; Jain, Narendra K

    2006-01-01

    The purpose of this research was to prepare floating microspheres consisting of (1) calcium silicate as porous carrier; (2) orlistat, an oral anti-obesity agent; and (3) Eudragit S as polymer, by solvent evaporation method and to evaluate their gastro-retentive and controlled-release properties. The effect of various formulation and process variables on the particle morphology, micromeritic properties, in vitro floating behavior, percentage drug entrapment, and in vitro drug release was studied. The gamma scintigraphy of the optimized formulation was performed in albino rabbits to monitor the transit of floating microspheres in the gastrointestinal tract. The orlistat-loaded optimized formulation was orally administered to albino rabbits, and blood samples collected were used to determine pharmacokinetic parameters of orlistat from floating microspheres. The microspheres were found to be regular in shape and highly porous. Microsphere formulation CS4, containing 200 mg calcium silicate, showed the best floating ability (88% +/- 4% buoyancy) in simulated gastric fluid as compared with other formulations. Release pattern of orlistat in simulated gastric fluid from all floating microspheres followed Higuchi matrix model and Peppas-Korsmeyer model. Prolonged gastric residence time of over 6 hours was achieved in all rabbits for calcium silicate-based floating microspheres of orlistat. The enhanced elimination half-life observed after pharmacokinetic investigations in the present study is due to the floating nature of the designed formulations. PMID:17233542

  8. Porous microsphere and its applications

    PubMed Central

    Cai, Yunpeng; Chen, Yinghui; Hong, Xiaoyun; Liu, Zhenguo; Yuan, Weien

    2013-01-01

    Porous microspheres have drawn great attention in the last two decades for their potential applications in many fields, such as carriers for drugs, absorption and desorption of substances, pulmonary drug delivery, and tissue regeneration. The application of porous microspheres has become a feasible way to address existing problems. In this essay, we give a brief introduction of the porous microsphere, its characteristics, preparation methods, applications, and a brief summary of existing problems and research tendencies. PMID:23515359

  9. Corneal Confocal Microscopy Detects Small Fibre Neuropathy in Patients with Upper Gastrointestinal Cancer and Nerve Regeneration in Chemotherapy Induced Peripheral Neuropathy

    PubMed Central

    Ferdousi, Maryam; Azmi, Shazli; Petropoulos, Ioannis Nikolaos; Fadavi, Hassan; Ponirakis, Georgios; Marshall, Andrew; Tavakoli, Mitra; Malik, Imaan; Mansoor, Wasat; Malik, Rayaz Ahmed

    2015-01-01

    There are multiple neurological complications of cancer and its treatment. This study assessed the utility of the novel non-invasive ophthalmic technique of corneal confocal microscopy in identifying neuropathy in patients with upper gastrointestinal cancer before and after platinum based chemotherapy. In this study, 21 subjects with upper gastrointestinal (oesophageal or gastric) cancer and 21 healthy control subjects underwent assessment of neuropathy using the neuropathy disability score, quantitative sensory testing for vibration perception threshold, warm and cold sensation thresholds, cold and heat induced pain thresholds, nerve conduction studies and corneal confocal microscopy. Patients with gastro-oesophageal cancer had higher heat induced pain (P = 0.04) and warm sensation (P = 0.03) thresholds with a significantly reduced sural sensory (P<0.01) and peroneal motor (P<0.01) nerve conduction velocity, corneal nerve fibre density (CNFD), nerve branch density (CNBD) and nerve fibre length (CNFL) (P<0.0001). Furthermore, CNFD correlated significantly with the time from presentation with symptoms to commencing chemotherapy (r = -0.54, P = 0.02), and CNFL (r = -0.8, P<0.0001) and CNBD (r = 0.63, P = 0.003) were related to the severity of lymph node involvement. After the 3rd cycle of chemotherapy, there was no change in any measure of neuropathy, except for a significant increase in CNFL (P = 0.003). Corneal confocal microscopy detects a small fibre neuropathy in this cohort of patients with upper gastrointestinal cancer, which was related to disease severity. Furthermore, the increase in CNFL after the chemotherapy may indicate nerve regeneration. PMID:26430773

  10. Functional magnetic microspheres

    NASA Technical Reports Server (NTRS)

    Yen, Shiao-Ping S. (Inventor); Rembaum, Alan (Inventor); Landel, Robert F. (Inventor)

    1981-01-01

    Functional magnetic particles are formed by dissolving a mucopolysaccharide such as chitosan in acidified aqueous solution containing a mixture of ferrous chloride and ferric chloride. As the pH of the solution is raised magnetite is formed in situ in the solution by raising the pH. The dissolved chitosan is a polyelectrolyte and forms micelles surrounding the granules at pH of 8-9. The chitosan precipitates on the granules to form microspheres containing the magnetic granules. On addition of the microspheres to waste aqueous streams containing dissolved ions, the hydroxyl and amine functionality of the chitosan forms chelates binding heavy metal cations such as lead, copper, and mercury and the chelates in turn bind anions such as nitrate, fluoride, phosphate and borate.

  11. Trading polymeric microspheres: exchanging DNA molecules via microsphere interaction.

    PubMed

    Morimoto, Nobuyuki; Muramatsu, Kanna; Nomura, Shin-ichiro M; Suzuki, Makoto

    2015-04-01

    A new class of artificial molecular transport system is constructed by polymeric microspheres. The microspheres are prepared by self-assembly of poly(ethylene glycol)-block-poly(3-dimethyl(methacryloyloxyethyl)ammonium propane sulfonate), PEG-b-PDMAPS, by intermolecular dipole-dipole interaction of sulfobetaine side chains in water. Below the upper critical solution temperature (UCST) of PEG-b-PDMAPS, the microspheres (∼1μm) interact with other microspheres by partial and transit fusion. In order to apply the interaction between microspheres, a 3'-TAMRA-labeled single-stranded DNA oligomer (ssDNA) is encapsulated into a PEG-b-PDMAPS microsphere by thermal treatment. The exchange of ssDNA between microspheres is confirmed by fluorescence resonance energy transfer (FRET) quenching derived from double-stranded formation with complementary 5'-BHQ-2-labeled ssDNA encapsulated in PEG-b-PDMAPS microspheres. The exchange rate of ssDNA is controllable by tuning the composition of the polymer. The contact-dependent transport of molecules can be applied in the areas of microreactors, sensor devices, etc. PMID:25731098

  12. Pentadecapeptide BPC 157 positively affects both non-steroidal anti-inflammatory agent-induced gastrointestinal lesions and adjuvant arthritis in rats.

    PubMed

    Sikiric, P; Seiwerth, S; Grabarevic, Z; Rucman, R; Petek, M; Jagic, V; Turkovic, B; Rotkvic, I; Mise, S; Zoricic, I; Konjevoda, P; Perovic, D; Simicevic, V; Separovic, J; Hanzevacki, M; Ljubanovic, D; Artukovic, B; Bratulic, M; Tisljar, M; Rekic, B; Gjurasin, M; Miklic, P; Buljat, G

    1997-01-01

    Besides a superior protection of the pentadecapeptide BPC 157 (an essential fragment of an organoprotective gastric juice peptide BPC) against different gastrointestinal and liver lesions, an acute anti-inflammatory and analgetic activity was also noted. Consequently, its effect on chronic inflammation lesions, such as adjuvant arthritis, and non-steroidal anti-inflammatory agents (NSAIAs)-induced gastrointestinal lesions was simultaneously studied in rats. In gastrointestinal lesions (indomethacin (30 mg/kg s.c.), aspirin (400 mg/kg i.g.) and diclofenac (125 mg/kg i.p.) studies, BPC 157 (10 micrograms or 10 ng/kg i.p.) was regularly given simultaneously and/or 1 h prior to drug application (indomethacin). In the adjuvant arthritis (tail-application of 0.2 mL of Freund's adjuvant) studies (14 days, 30 days, 1 year) BPC 157 (10 micrograms or 10 ng/kg i.p.), it was given as a single application (at 1 h either before or following the application of Freund's adjuvant) or in a once daily regimen (0-14th day, 14-30th day, 14th day-1 year). Given with the investigated NSAIAs, BPC 157 consistently reduced the otherwise prominent lesions in the stomach of the control rats, as well as the lesions in the small intestine in the indomethacin groups. In the adjuvant arthritis studies, the lesion's development seems to be considerably reduced after single pentadecapeptide medication, and even more attenuated in rats daily treated with BPC 157. As a therapy of already established adjuvant arthritis, its salutary effect consistently appeared already after 2 weeks of medication and it could be clearly seen also after 1 year of application. Taking together all these results, the data likely point to a special anti-inflammatory and mucosal integrity protective effect. PMID:9403784

  13. Protocol for a randomised control trial of methylnaltrexone for the treatment of opioid-induced constipation and gastrointestinal stasis in intensive care patients (MOTION)

    PubMed Central

    Patel, Parind B; Brett, Stephen J; O'Callaghan, David; Anjum, Aisha; Cross, Mary; Warwick, Jane; Gordon, Anthony C

    2016-01-01

    Introduction Gastrointestinal dysmotility and constipation are common problems in intensive care patients. The majority of critical care patients are sedated with opioids to facilitate tolerance of endotracheal tubes and mechanical ventilation, which inhibit gastrointestinal motility and lead to adverse outcomes. Methylnaltrexone is a peripheral opioid antagonist that does not cross the blood–brain barrier and can reverse the peripheral side effects of opioids without affecting the desired central properties. This trial will investigate whether methylnaltrexone can reverse opioid-induced constipation and gastrointestinal dysmotility. Methods This is a single-centre, multisite, double-blind, randomised, placebo-controlled trial. 84 patients will be recruited from 4 intensive care units (ICUs) within Imperial College Healthcare NHS Trust. Patients will receive intravenous methylnaltrexone or placebo on a daily basis if they are receiving opioid infusion to facilitate mechanical ventilation and have not opened their bowels for 48 hours. All patients will receive standard laxatives as per the clinical ICU bowel protocol prior to randomisation. The primary outcome of the trial will be time to significant rescue-free laxation following randomisation. Secondary outcomes will include tolerance of enteral feed, gastric residual volumes, incidence of pneumonia, blood stream and Clostridium difficile infection, and any reversal of central opioid effects. Ethics and dissemination The trial protocol, the patient/legal representative information sheets and consent forms have been reviewed and approved by the Harrow Research Ethics Committee (REC Reference 14/LO/2004). An independent Trial Steering Committee and Data Monitoring Committee are in place, with patient representation. On completion, the trial results will be published in peer-reviewed journals and presented at national and international scientific meetings. Trial registration number 2014-004687-37; Pre

  14. Is gastrointestinal dysfunction induced by gastric cancer peritoneal metastasis relevant to impairment of interstitial cells of Cajal?

    PubMed

    Zheng, Hongqun; He, Yan; Tong, Jinxue; Sun, Lingyu; Yang, Dongdong; Li, Huaming; Ao, Ning; Jin, Xiaoming; Zhang, Qifan

    2011-03-01

    Although impaired gastrointestinal motility from gastric cancer peritoneal metastasis (GCPM) causes extraordinary pain, its cause is unclear. Interstitial cells of Cajal (ICC) are apparently pacemaker cells, and their loss could cause motor dysfunction. In this study, we developed a mouse model for GCPM, and investigated electrophysiological changes in the small intestine and attendant changes in ICC. We found decreased ICC and disrupted electrical rhythm in the model. Pathologic ICC changes were well described. Cancer peritoneal metastasis may impair intestinal myoelectrical activity by damaging ICC and ICC networks. Interstitial cells of Cajal will be a target of palliative treatment and merit further study. PMID:21207119

  15. Photonic nanojet-induced modes in chains of size-disordered microspheres with an attenuation of only 0.08 dB per sphere

    NASA Astrophysics Data System (ADS)

    Yang, Seungmoo; Astratov, Vasily N.

    2008-06-01

    By using spatially resolved spectroscopy the authors demonstrate that the periodical focusing of light in straight chains of touching 5μm polystyrene microspheres is characterized with the periodicity of photonic nanojets corresponding to the size of two spheres. In transmission spectra of long (>20 spheres) chains they observe Fabry-Pérot fringes with propagation losses of only 0.08dB per sphere in the maxima of transmission peaks. Due to mechanical robustness, tight focusing of the beam, high optical throughput, and broad spectral transmission properties such chains can be used in a variety of biomedical applications as optical microprobes with subwavelength spatial resolution.

  16. Metal containing polymeric functional microspheres

    NASA Technical Reports Server (NTRS)

    Yen, Shiao-Ping S. (Inventor); Rembaum, Alan (Inventor); Molday, Robert S. (Inventor)

    1979-01-01

    Polymeric functional microspheres containing metal or metal compounds are formed by addition polymerization of a covalently bondable olefinic monomer such as hydroxyethylmethacrylate in the presence of finely divided metal or metal oxide particles, such as iron, gold, platinum or magnetite, which are embedded in the resulting microspheres. The microspheres can be covalently bonded to chemotherapeutic agents, antibodies, or other proteins providing a means for labeling or separating labeled cells. Labeled cells or microspheres can be concentrated at a specific body location such as in the vicinity of a malignant tumor by applying a magnetic field to the location and then introducing the magnetically attractable microspheres or cells into the circulatory system of the subject. Labeled cells can be separated from a cell mixture by applying a predetermined magnetic field to a tube in which the mixture is flowing. After collection of the labeled cells, the magnetic field is discontinued and the labeled sub-cell population recovered.

  17. Immunofluorescence detection methods using microspheres

    NASA Astrophysics Data System (ADS)

    Szurdoki, Ferenc; Michael, Karri L.; Agrawal, Divya; Taylor, Laura C.; Schultz, Sandra L.; Walt, David R.

    1999-01-01

    Microsphere-based immunoassays were devised for compounds of agricultural and biomedical interest (e.g., digoxin, theophylline, and zearalenone). Commercially available microspheres with surface functional groups for chemical derivatization were used as solid carriers. After immobilizing the target substances, the surface of the haptenized microspheres was blocked by a protein to reduce aspecific binding. Competitive immunoassays were performed using the functionalized microspheres and antibodies labeled with horseradish peroxidase. Immunofluorescence signal amplification was achieved by enzyme-catalyzed reporter deposition (CARD). An epifluorescence microscope, a CCD camera interfaced with a computer, and microscopy image analysis software were employed for quantitative detection of fluorescent light emitted from individual microspheres. Integration of several such immunoassays and application of an optical encoding method enabled multianalyte determination. These immunoassays can also be utilized in an immunosensor array format. This immunoarray format could facilitate miniaturization and automation of multianalyte immunoassays.

  18. In situ fabrication of a perfect Pd/ZnO@ZIF-8 core-shell microsphere as an efficient catalyst by a ZnO support-induced ZIF-8 growth strategy

    NASA Astrophysics Data System (ADS)

    Lin, Lu; Zhang, Tong; Liu, Haiou; Qiu, Jieshan; Zhang, Xiongfu

    2015-04-01

    Controllable encapsulation of nanoparticles with metal organic frameworks (MOFs) has been an efficient way to impart the unique chemical and physical properties of the nanoparticles to metal organic frameworks and create new types of multifunctional MOF core-shell materials with enhanced properties. Here, a novel ZnO support-induced encapsulation strategy is reported to efficiently fabricate a Pd/ZnO@ZIF-8 core-shell catalyst, with Pd/ZnO as the core and ZIF-8 as the shell. The novel synthesis procedure involves first loading Pd nanoparticles onto the surface of the ZnO microsphere to form a Pd/ZnO core and then coating the core with a layer of defect-free ZIF-8 shell via ZnO-induced in situ ZIF-8 growth to obtain the Pd/ZnO@ZIF-8 core-shell catalyst. It was crucial that the ZIF-8 was in situ formed from the ZnO core in an ethanol solution only containing 2-methylimidazole under mild conditions. This strategy allowed for the growth of ZIF-8 right on the surface of Pd/ZnO via the reaction between ZnO and the 2-methylimidazole ligands, and thus avoided the random deposition of ZIF-8 crystals on the Pd/ZnO core as in the case of the conventional ZIF-8 synthesis solution. Furthermore, use of ethanol as the solvent also favored achievement of the well-defined Pd/ZnO@ZIF-8 structure, since the ethanol solution of 2-methylimidazole was able to keep the balance between ZnO dissolution and ZIF-8 formation. The as-prepared Pd/ZnO@ZIF-8 core-shell microsphere as an efficient catalyst displayed excellent performance in terms of size-selectivity, stability and anti-poisoning in the liquid hydrogenations of alkenes.

  19. Effects of early enteral nutrition on the gastrointestinal motility and intestinal mucosal barrier of patients with burn-induced invasive fungal infection

    PubMed Central

    Zhang, Yu; Gu, Fang; Wang, Fengxian; Zhang, Yuanda

    2016-01-01

    Objective: To evaluate the effects of early enteral nutrition on the gastrointestinal motility and intestinal mucosal barrier of patients with burn-induced invasive fungal infection. Methods: A total of 120 patients with burn-induced invasive fungal infection were randomly divided into an early enteral nutrition (EN) group and a parenteral nutrition (PN) group (n=60). The patients were given nutritional support intervention for 14 days, and the expression levels of serum transferrin, albumin, total protein, endotoxin, D-lactic acid and inflammatory cytokines were detected on the 1st, 7th and 14th days respectively. Results: As the treatment progressed, the levels of serum transferrin, albumin and total protein of the EN group were significantly higher than those of the PN group (P<0.05), while the levels of serum endotoxin and D-lactic acid of the form group were significantly lower (P<0.05). After treatment, the expression levels of IL-6 and TNF-α were decreased in the EN group, which were significantly different from those of the PN group (P<0.05). During treatment, the incidence rates of complications such as abdominal distension, diarrhea, sepsis, nausea, vomiting and gastric retention were similar. The mean healing time of wound surface was 9.34±0.78 days in the EN group and 12.46±2.19 days in the PN group, i.e. such time of the former was significantly shorter than that of the latter (P<0.05). Conclusion: Treating patients having burn-induced invasive fungal infection by early enteral nutrition support with arginine can safely alleviate malnutrition and stress reaction, strengthen cellular immune function and promote wound healing, thereby facilitating the recovery of gastrointestinal motility and the function of intestinal mucosal barrier. PMID:27375697

  20. Enteropathogenic Escherichia coli protein secretion is induced in response to conditions similar to those in the gastrointestinal tract.

    PubMed Central

    Kenny, B; Abe, A; Stein, M; Finlay, B B

    1997-01-01

    The pathogenicity of enteropathogenic Escherichia coli (EPEC) is associated with the expression and secretion of specific bacterial factors. EspB is one such secreted protein which is required to trigger host signaling pathways resulting in effacement of microvilli and cytoskeletal rearrangements. These events presumably contribute to the ensuing diarrhea associated with EPEC infections. EPEC encounters several environmental changes and stimuli during its passage from the external environment into the host gastrointestinal tract. In this paper we show that the secretion of EspB is subject to environmental regulation, and maximal secretion occurs under conditions reminiscent of those in the gastrointestinal tract. Thus, secretion is maximal at 37 degrees C, pH 7, and physiological osmolarity. In addition, maximal secretion requires the presence of sodium bicarbonate and calcium and is stimulated by millimolar concentrations of Fe(NO3)3. The secretion of the four other EPEC-secreted proteins appears to be modulated in a manner similar to that of EspB. Our results also show that secretion is not dependent on CO2, as originally reported by Haigh et al. (FEMS Microbiol. Lett. 129: 63-67, 1995), but that CO2 more likely acts as a component of the medium buffering system, since CO2 dependence was abolished by the use of alternative buffers. PMID:9199427

  1. Gastrointestinal food allergies.

    PubMed

    Heine, Ralf G

    2015-01-01

    Gastrointestinal food allergies present during early childhood with a diverse range of symptoms. Cow's milk, soy and wheat are the three most common gastrointestinal food allergens. Several clinical syndromes have been described, including food protein-induced enteropathy, proctocolitis and enterocolitis. In contrast with immediate, IgE-mediated food allergies, the onset of gastrointestinal symptoms is delayed for at least 1-2 hours after ingestion in non-IgE-mediated allergic disorders. The pathophysiology of these non-IgE-mediated allergic disorders is poorly understood, and useful in vitro markers are lacking. The results of the skin prick test or measurement of the food-specific serum IgE level is generally negative, although low-positive results may occur. Diagnosis therefore relies on the recognition of a particular clinical phenotype as well as the demonstration of clear clinical improvement after food allergen elimination and the re-emergence of symptoms upon challenge. There is a significant clinical overlap between non-IgE-mediated food allergy and several common paediatric gastroenterological conditions, which may lead to diagnostic confusion. The treatment of gastrointestinal food allergies requires the strict elimination of offending food allergens until tolerance has developed. In breast-fed infants, a maternal elimination diet is often sufficient to control symptoms. In formula-fed infants, treatment usually involves the use an extensively hydrolysed or amino acid-based formula. Apart from the use of hypoallergenic formulae, the solid diets of these children also need to be kept free of specific food allergens, as clinically indicated. The nutritional progress of infants and young children should be carefully monitored, and they should undergo ongoing, regular food protein elimination reassessments by cautious food challenges to monitor for possible tolerance development. PMID:26022877

  2. Chalcogenide glass microsphere laser.

    PubMed

    Elliott, Gregor R; Murugan, G Senthil; Wilkinson, James S; Zervas, Michalis N; Hewak, Daniel W

    2010-12-01

    Laser action has been demonstrated in chalcogenide glass microsphere. A sub millimeter neodymium-doped gallium lanthanum sulphide glass sphere was pumped at 808 nm with a laser diode and single and multimode laser action demonstrated at wavelengths between 1075 and 1086 nm. The gallium lanthanum sulphide family of glass offer higher thermal stability compared to other chalcogenide glasses, and this, along with an optimized Q-factor for the microcavity allowed laser action to be achieved. When varying the pump power, changes in the output spectrum suggest nonlinear and/or thermal effects have a strong effect on laser action. PMID:21165022

  3. Photonic crystal microspheres

    NASA Astrophysics Data System (ADS)

    Zhokhov, A. A.; Masalov, V. M.; Sukhinina, N. S.; Matveev, D. V.; Dolganov, P. V.; Dolganov, V. K.; Emelchenko, G. A.

    2015-11-01

    Spherical samples of photonic crystals formed by colloidal SiO2 nanoparticles were synthesized. Synthesis of microspheres from 160 nm, 200 nm and 430 nm diameter colloidal nanoparticles was performed over a wide size range, from 5 μm to 50 μm. The mechanism of formation of void microparticles exceeding 50 μm is discussed. The spectral measurements verified the association of the spectra with the peaks of selective reflection from the cubic lattice planes. The microparticle morphology is characterized by scanning electron microscopy (SEM).

  4. Particle Tracking of Fluorescent Microspheres

    NASA Astrophysics Data System (ADS)

    Kaminski, Zofia; Mueller, Joachim; Berk, Serkan

    2010-10-01

    In this research, the diffusion coefficients of the fluorescent microspheres and the relation of those coefficients to particle radius were investigated. An additional focus was to see how well the measured radius of the microspheres compared to the radius as reported by the manufacturer and to measure the distribution of radii in a sample. This study further developed the critical process of ensuring particle movement within the sample volume and made preliminary sample measurements.The methods developed for tracking microspheres will later be used to determine the radii of virus like particles (VLPs), which are a non-infectious model system of the HIV virus. Results from our measurements will be reported.

  5. Microsphere based saliva diagnostics

    NASA Astrophysics Data System (ADS)

    Rissin, David M.; DiCesare, Christopher; Hayman, Ryan B.; Blicharz, Timothy M.; Walt, David R.

    2005-11-01

    Saliva presents a minimally invasive alternative medium to blood for performing diagnostics1. Microsphere sensors for ions, small organic molecules, and proteins are currently being developed and optical microarrays containing thousands of these sensors will be used for simultaneous multi-analyte analysis. The fiber bundle platform in use is 1mm in diameter and contains approximately 50,000 individually addressable 3.1μm fibers, each with an etched well capable of housing a single 3.1μm microsphere sensor. Micron-sized bead-based chemistries are produced in house, followed by deposition onto a fiber-optic bundle platform, allowing for multiplexed analysis. The ultimate goal is to develop a universal diagnostic system using saliva as the diagnostic medium. This platform will permit multiplexed analysis of a sample by integrating microfluidics with the optical arrays loaded with sensors capable of detecting relevant biomarkers associated with a wide range of disease states. Disease states that are currently under investigation include end stage renal disease (ESRD) and Sjoegrens Syndrome (SS).

  6. Enhancement of Poly(orthoester) Microspheres for DNA Vaccine Delivery by Blending with Poly(ethylenimine)

    PubMed Central

    Nguyen, David N.; Raghavan, Shyam S.; Tashima, Lauren M.; Lin, Elizabeth C.; Fredette, Stephen J.; Langer, Robert S.; Wang, Chun

    2008-01-01

    Poly(ortho ester) (POE) microspheres have been previously shown to possess certain advantages for the in vivo delivery of DNA vaccines. In particular, timing of DNA release from POE microspheres in response to acidic phagosomal pH was shown to be an important factor in determining immunogenicity, which was hypothesized to be linked to the natural progression of antigen presenting cell uptake, transfection, maturation, and antigen presentation. Here we report in vitro characterization of the enhanced the efficacy of POE microspheres by blending poly(ethylenimine) (PEI), a well-characterized cationic transfection agent, into the POE matrix. Blending of a tiny amount of PEI (approximately 0.04 wt%) with POE caused large alterations in POE microsphere properties. PEI provided greater control over the rate of pH-triggered DNA release by doubling the total release time of plasmid DNA and enhanced gene transfection efficiency of the microspheres up to 50-fold without any significant cytotoxicity. Confocal microscopy with labeled PEI and DNA plasmids revealed that PEI caused a surface-localizing distribution of DNA and PEI within the POE microsphere as well as focal co-localization of PEI with DNA. We provide evidence that upon degradation, the microspheres of POE-PEI blends released electrostatic complexes of DNA and PEI, which are responsible for the enhanced gene transfection. Furthermore, blending PEI into the POE microsphere induced 50% to 60% greater phenotypic maturation and activation of bone marrow-derived dendritic cells in vitro, judged by up-regulation of co-stimulatory markers on the cell surface. Physically blending PEI with POE is a simple approach for modulating the properties of biodegradable microspheres in terms of gene transfection efficiency and DNA release kinetics. Combined with the ability to induce maturation of antigen-presenting cells, POE-PEI blended microspheres may be excellent carriers for DNA vaccines. PMID:18400294

  7. Nasal immunization with mannan-decorated mucoadhesive HPMCP microspheres containing ApxIIA toxin induces protective immunity against challenge infection with Actinobacillus pleuropneumoiae in mice.

    PubMed

    Li, Hui-Shan; Shin, Min-Kyoung; Singh, Bijay; Maharjan, Sushila; Park, Tae-Eun; Kang, Sang-Kee; Yoo, Han-Sang; Hong, Zhong-Shan; Cho, Chong-Su; Choi, Yun-Jaie

    2016-07-10

    The development of subunit mucosal vaccines requires an appropriate delivery system or an immune modulator such as an adjuvant to improve antigen immunogenicity. The nasal route for vaccine delivery by microparticles has attracted considerable interest, although challenges such as the rapid mucociliary clearance in the respiratory mucosa and the low immunogenicity of subunit vaccine still remain. Here, we aimed to develop mannan-decorated mucoadhesive thiolated hydroxypropylmethyl cellulose phthalate (HPMCP) microspheres (Man-THM) that contain ApxIIA subunit vaccine - an exotoxin fragment as a candidate for a subunit nasal vaccine against Actinobacillus pleuropneumoniae. For adjuvant activity, mucoadhesive thiolated HPMCP microspheres decorated with mannan could be targeted to the PRRs (pathogen recognition receptors) and mannose receptors (MR) of antigen presenting cells (APCs) in the respiratory immune system. The potential adjuvant ability of Man-THM for intranasal immunization was confirmed by in vitro and in vivo experiments. In a mechanistic study using APCs in vitro, it was found that Man-THM enhanced receptor-mediated endocytosis by stimulating the MR of APCs. In vivo, the nasal vaccination of ApxIIA-loaded Man-THM in mice resulted in higher levels of mucosal sIgA and serum IgG than mice in the ApxIIA and ApxIIA-loaded THM groups due to the specific recognition of the mannan in the Man-THM by the MRs of the APCs. Moreover, ApxIIA-containing Man-THM protected immunized mice when challenged with strains of A. pleuropneumoniae serotype 5. These results suggest that mucoadhesive Man-THM may be a promising candidate for a nasal vaccine delivery system to elicit systemic and mucosal immunity that can protect from pathogenic bacteria infection. PMID:27189136

  8. Glass microsphere lubrication

    NASA Technical Reports Server (NTRS)

    Geiger, Michelle; Goode, Henry; Ohanlon, Sean; Pieloch, Stuart; Sorrells, Cindy; Willette, Chris

    1991-01-01

    The harsh lunar environment eliminated the consideration of most lubricants used on earth. Considering that the majority of the surface of the moon consists of sand, the elements that make up this mixture were analyzed. According to previous space missions, a large portion of the moon's surface is made up of fine grained crystalline rock, about 0.02 to 0.05 mm in size. These fine grained particles can be divided into four groups: lunar rock fragments, glasses, agglutinates (rock particles, crystals, or glasses), and fragments of meteorite material (rare). Analysis of the soil obtained from the missions has given chemical compositions of its materials. It is about 53 to 63 percent oxygen, 16 to 22 percent silicon, 10 to 16 percent sulfur, 5 to 9 percent aluminum, and has lesser amounts of magnesium, carbon, and sodium. To be self-supporting, the lubricant must utilize one or more of the above elements. Considering that the element must be easy to extract and readily manipulated, silicon or glass was the most logical choice. Being a ceramic, glass has a high strength and excellent resistance to temperature. The glass would also not contaminate the environment as it comes directly from it. If sand entered a bearing lubricated with grease, the lubricant would eventually fail and the shaft would bind, causing damage to the system. In a bearing lubricated with a solid glass lubricant, sand would be ground up and have little effect on the system. The next issue was what shape to form the glass in. Solid glass spheres was the only logical choice. The strength of the glass and its endurance would be optimal in this form. To behave as an effective lubricant, the diameter of the spheres would have to be very small, on the order of hundreds of microns or less. This would allow smaller clearances between the bearing and the shaft, and less material would be needed. The production of glass microspheres was divided into two parts, production and sorting. Production includes the

  9. Ultrasonic atomization for spray drying: a versatile technique for the preparation of protein loaded biodegradable microspheres.

    PubMed

    Bittner, B; Kissel, T

    1999-01-01

    Bovine serum albumin (BDA) loaded microspheres with a spherical shape and smooth surface structure were successfully prepared from poly(lactide-co-glycolide) using an ultrasonic nozzle installed in a Niro laboratory spray dryer. Process and formulation parameters were investigated with respect to their influence on microsphere characteristics, such as particle size, loading capacity, and release properties. Preparation of microspheres in yields of more than 50% was achieved using an ultrasonic atomizer connected to a stream of carrier air. Microsphere characteristics could be modified by changing several technological parameters. An increased polymer concentration of the feed generated larger particles with a significantly reduced initial release of the protein. Moreover, microspheres with a smooth surface structure were obtained from the organic polymer solution with the highest viscosity. Microparticles with a low BSA loading showed a large central cavity surrounded by a thin polymer layer in scanning electron microspheres. A high protein loading led to an enlargement of the shell layer, or even to dense particles without any cavities. A continuous in vitro release pattern of BSA was obtained from the particles with low protein loading. Glass transition temperatures (Tg) of the microspheres before and after lyophilization did not differ from those of the BSA loaded particles prepared by spray drying with a rotary atomizer. Analysis of the polymer by gel permeation chromatography indicated that ultrasonication had no effect on polymer molecular weight. Molecular weight and polydispersity of the pure polymer, placebo microspheres prepared by spray drying, and placebo microspheres prepared using the ultrasonic nozzle were in the same range. In conclusion, ultrasonic atomization represents a versatile and reliable technique for the production of protein loaded biodegradable microspheres without inducing a degradation of the polymer matrix. Particle characteristics

  10. Predictors of radiation-induced gastrointestinal morbidity: A prospective, longitudinal study following radiotherapy for carcinoma of the prostate.

    PubMed

    Yeoh, Eric K; Krol, Robin; Dhillon, Varinderpal S; Botten, Rochelle; Di Matteo, Addolorata; Butters, Julie; Brock, Aleisha R; Esterman, Adrian; Salisbury, Carolyn; Fenech, Michael

    2016-05-01

    Background Chronic gastrointestinal (GI) morbidity occurs in ≥50% of patients after external beam radiotherapy (EBRT) for carcinoma of prostate (CaP). This prospective, longitudinal study examines which baseline measurements of: 1) homocysteine and micronutrients in plasma; 2) chromosome damage/misrepair biomarkers; and 3) anal and rectal dose volume metrics predict GI morbidity after EBRT. Patients and methods In total, 106 patients with CaP had evaluations of GI symptoms (modified LENT-SOMA questionnaires) before EBRT and at one month, one, two and three years after its completion. Other variables measured before EBRT were: 1) plasma concentrations of homocysteine and micronutrients including caroteinoids and selenium; 2) chromosome damage/DNA misrepair (micronuclei/nucleoplasmic bridge) indices; and 3) mean anal and rectal wall doses and volumes of anal and rectal walls receiving ≥40 Gy and ≥60 Gy. Univariate and multivariate analyzes examined the relationships among: 1) plasma levels of homocysteine and micronutrients; 2) indices of chromosome damage/DNA misrepair; and 3) mean anal and rectal wall doses and volumes of anal and rectal walls receiving ≥40 Gy and ≥60 Gy and total GI symptom scores from one month to three years after EBRT. Results Increased frequency and urgency of defecation, rectal mucous discharge and bleeding after EBRT resulted in sustained rises in total GI symptom scores above baseline at three years. On univariate analysis, total GI symptom scores were significantly associated with: 1) plasma selenium and α tocopherol; 2) micronuclei indices of DNA damage; 3) mean anal and rectal wall doses; and 4) volumes of anal and rectal wall receiving ≥40 Gy and ≥60 Gy (p = 0.08-<0.001). On multivariate analysis, only volume of anal wall receiving ≥40 Gy was significant for increased GI symptoms after EBRT (p < 0.001). Conclusion The volume of anal wall receiving ≥40 Gy predicts chronic GI morbidity after EBRT for CaP. PMID

  11. Osteoporosis in Gastrointestinal Diseases.

    PubMed

    Krela-Kaźmierczak, Iwona; Szymczak, Aleksandra; Łykowska-Szuber, Liliana; Eder, Piotr; Linke, Krzysztof

    2016-01-01

    Secondary osteoporosis occurs as an isolated pathology or co-exists with types I and II osteoporosis. The gastroenterologist may come across osteoporosis or osteopenia in a patient with a gastrointestinal disease. This is often a young patient in whom investigations should be carried out and appropriate treatment initiated, aimed at preventing bone fractures and the formation of the best peak bone mass. Osteoporosis occurs in patients with the following conditions: Crohn's disease, ulcerative colitis, celiac disease, post gastrectomy patients, patients with short bowel syndrome, chronic hepatitis and cirrhosis, treated with steroids (steroid-induced osteoporosis) and patients using proton pump inhibitors chronically (state of achlorhydria). It is therefore necessary to approve a list of risk factors of secondary osteoporosis, the presence of which would be an indication for screening for osteoporosis, including a DXA study and the development of a separate algorithm for the therapeutic management of secondary osteoporosis accompanying gastrointestinal diseases, especially in premenopausal young women and young men, because there are currently no registered drugs with proven antifracture activity for this group of patients. PMID:26935513

  12. Fabrication of glass microspheres with conducting surfaces

    DOEpatents

    Elsholz, William E.

    1984-01-01

    A method for making hollow glass microspheres with conducting surfaces by adding a conducting vapor to a region of the glass fabrication furnace. As droplets or particles of glass forming material pass through multiple zones of different temperature in a glass fabrication furnace, and are transformed into hollow glass microspheres, the microspheres pass through a region of conducting vapor, forming a conducting coating on the surface of the microspheres.

  13. Fabrication of glass microspheres with conducting surfaces

    DOEpatents

    Elsholz, W.E.

    1982-09-30

    A method for making hollow glass microspheres with conducting surfaces by adding a conducting vapor to a region of the glass fabrication furnace. As droplets or particles of glass forming material pass through multiple zones of different temperature in a glass fabrication furnace, and are transformed into hollow glass microspheres, the microspheres pass through a region of conducting vapor, forming a conducting coating on the surface of the microspheres.

  14. Zinc and gastrointestinal disease

    PubMed Central

    Skrovanek, Sonja; DiGuilio, Katherine; Bailey, Robert; Huntington, William; Urbas, Ryan; Mayilvaganan, Barani; Mercogliano, Giancarlo; Mullin, James M

    2014-01-01

    This review is a current summary of the role that both zinc deficiency and zinc supplementation can play in the etiology and therapy of a wide range of gastrointestinal diseases. The recent literature describing zinc action on gastrointestinal epithelial tight junctions and epithelial barrier function is described. Zinc enhancement of gastrointestinal epithelial barrier function may figure prominently in its potential therapeutic action in several gastrointestinal diseases. PMID:25400994

  15. Pediatric upper gastrointestinal studies.

    PubMed

    Odgren, Mike

    2014-01-01

    Upper gastrointestinal examinations are common procedures in many radiology departments. Performing this examination on pediatric patients requires understanding the formation of the gastrointestinal tract and the various disease processes and anatomical variances that can occur. The examination also requires a thorough patient history. This article discusses embryologic development and anatomy of the small bowel and colon, disease processes and conditions of the upper gastrointestinal tract, and fluoroscopic upper gastrointestinal tract examinations performed on the pediatric and neonatal patient. PMID:24806054

  16. Interaction Induced High Catalytic Activities of CoO Nanoparticles Grown on Nitrogen-Doped Hollow Graphene Microspheres for Oxygen Reduction and Evolution Reactions

    NASA Astrophysics Data System (ADS)

    Jiang, Zhong-Jie; Jiang, Zhongqing

    2016-06-01

    Nitrogen doped graphene hollow microspheres (NGHSs) have been used as the supports for the growth of the CoO nanoparticles. The nitrogen doped structure favors the nucleation and growth of the CoO nanoparticles and the CoO nanoparticles are mostly anchored on the quaternary nitrogen doped sites of the NGHSs with good monodispersity since the higher electron density of the quaternary nitrogen favors the nucleation and growth of the CoO nanoparticles through its coordination and electrostatic interactions with the Co2+ ions. The resulting NGHSs supported CoO nanoparticles (CoO/NGHSs) are highly active for the oxygen reduction reaction (ORR) with activity and stability higher than the Pt/C and for the oxygen evolution reaction (OER) with activity and stability comparable to the most efficient catalysts reported to date. This indicates that the CoO/NGHSs could be used as efficient bi-functional catalysts for ORR and OER. Systematic analysis shows that the superior catalytic activities of the CoO/NGHSs for ORR and OER mainly originate from the nitrogen doped structure of the NGHSs, the small size of the CoO nanoparticles, the higher specific and electroactive surface area of the CoO/NGHSs, the good electric conductivity of the CoO/NGHSs, the strong interaction between the CoO nanoparticles and the NGHSs, etc.

  17. Interaction Induced High Catalytic Activities of CoO Nanoparticles Grown on Nitrogen-Doped Hollow Graphene Microspheres for Oxygen Reduction and Evolution Reactions

    PubMed Central

    Jiang, Zhong-Jie; Jiang, Zhongqing

    2016-01-01

    Nitrogen doped graphene hollow microspheres (NGHSs) have been used as the supports for the growth of the CoO nanoparticles. The nitrogen doped structure favors the nucleation and growth of the CoO nanoparticles and the CoO nanoparticles are mostly anchored on the quaternary nitrogen doped sites of the NGHSs with good monodispersity since the higher electron density of the quaternary nitrogen favors the nucleation and growth of the CoO nanoparticles through its coordination and electrostatic interactions with the Co2+ ions. The resulting NGHSs supported CoO nanoparticles (CoO/NGHSs) are highly active for the oxygen reduction reaction (ORR) with activity and stability higher than the Pt/C and for the oxygen evolution reaction (OER) with activity and stability comparable to the most efficient catalysts reported to date. This indicates that the CoO/NGHSs could be used as efficient bi-functional catalysts for ORR and OER. Systematic analysis shows that the superior catalytic activities of the CoO/NGHSs for ORR and OER mainly originate from the nitrogen doped structure of the NGHSs, the small size of the CoO nanoparticles, the higher specific and electroactive surface area of the CoO/NGHSs, the good electric conductivity of the CoO/NGHSs, the strong interaction between the CoO nanoparticles and the NGHSs, etc. PMID:27255562

  18. Interaction Induced High Catalytic Activities of CoO Nanoparticles Grown on Nitrogen-Doped Hollow Graphene Microspheres for Oxygen Reduction and Evolution Reactions.

    PubMed

    Jiang, Zhong-Jie; Jiang, Zhongqing

    2016-01-01

    Nitrogen doped graphene hollow microspheres (NGHSs) have been used as the supports for the growth of the CoO nanoparticles. The nitrogen doped structure favors the nucleation and growth of the CoO nanoparticles and the CoO nanoparticles are mostly anchored on the quaternary nitrogen doped sites of the NGHSs with good monodispersity since the higher electron density of the quaternary nitrogen favors the nucleation and growth of the CoO nanoparticles through its coordination and electrostatic interactions with the Co(2+) ions. The resulting NGHSs supported CoO nanoparticles (CoO/NGHSs) are highly active for the oxygen reduction reaction (ORR) with activity and stability higher than the Pt/C and for the oxygen evolution reaction (OER) with activity and stability comparable to the most efficient catalysts reported to date. This indicates that the CoO/NGHSs could be used as efficient bi-functional catalysts for ORR and OER. Systematic analysis shows that the superior catalytic activities of the CoO/NGHSs for ORR and OER mainly originate from the nitrogen doped structure of the NGHSs, the small size of the CoO nanoparticles, the higher specific and electroactive surface area of the CoO/NGHSs, the good electric conductivity of the CoO/NGHSs, the strong interaction between the CoO nanoparticles and the NGHSs, etc. PMID:27255562

  19. Microspheres and their methods of preparation

    DOEpatents

    Bose, Anima B; Yang, Junbing

    2015-03-24

    Carbon microspheres are doped with boron to enhance the electrical and physical properties of the microspheres. The boron-doped carbon microspheres are formed by a CVD process in which a catalyst, carbon source and boron source are evaporated, heated and deposited onto an inert substrate.

  20. Multilayered polymer microspheres by thermal imprinting during microsphere growth.

    PubMed

    Takekoh, Ryu; Li, Wen-Hui; Burke, Nicholas A D; Stöver, Harald D H

    2006-01-11

    Modulation of the polymerization temperature in precipitation polymerizations was used to form onion-type polymer microspheres consisting of multiple nested layers. Specifically, the copolymerization of chloromethylstyrene and divinylbenzene-55 in acetonitrile, at temperatures ramping between 65 and 75 degrees C, led to monodisperse, cross-linked microspheres of about 10 mum diameter that have radial density profiles closely reflecting the thermal profiles used. This thermal imprinting is attributed to the copolymer formed being close to its theta point during the polymerization. As the microspheres grow by continuously capturing oligomers from solution, the resulting transient surface gel layer expands and contracts with temperature, and thus records the reaction temperature profile in the form of a corresponding density profile, even as it cross-links. PMID:16390152

  1. Advances in Microsphere Insulation Systems

    NASA Astrophysics Data System (ADS)

    Allen, M. S.; Baumgartner, R. G.; Fesmire, J. E.; Augustynowicz, S. D.

    2004-06-01

    Microsphere insulation, typically consisting of hollow glass bubbles, combines in a single material the desirable properties that other insulations only have individually. The material has high crush strength, low density, is noncombustible, and performs well in soft vacuum. Microspheres provide robust, low-maintenance insulation systems for cryogenic transfer lines and dewars. They also do not suffer from compaction problems typical of perlite that result in the necessity to reinsulate dewars because of degraded thermal performance and potential damage to its support system. Since microspheres are load bearing, autonomous insulation panels enveloped with lightweight vacuum-barrier materials can be created. Comprehensive testing performed at the Cryogenics Test Laboratory located at the NASA Kennedy Space Center demonstrated competitive thermal performance with other bulk materials. Test conditions were representative of actual-use conditions and included cold vacuum pressure ranging from high vacuum to no vacuum and compression loads from 0 to 20 psi. While microspheres have been recognized as a legitimate insulation material for decades, actual implementation has not been pursued. Innovative microsphere insulation system configurations and applications are evaluated.

  2. Risk factors associated with NSAID-induced upper gastrointestinal bleeding resulting in hospital admissions: A cross-sectional, retrospective, case series analysis in valencia, spain

    PubMed Central

    Marco, José Luis; Amariles, Pedro; Boscá, Beatriz; Castelló, Ana

    2007-01-01

    Abstract Background NSAIDs are a significant cause of drug-related hospital admissions and deaths. The therapeutic effects of NSAIDs have been associated with the risk for developing adverse events, mainly in the gastrointestinal tract. Objectives The focus of this study was to identify the most common risk factors associated with NSAID-induced upper gastrointestinal bleeding (UGIB) resulting in hospital admissions. A secondary end point was the relationship between use of gastroprotective treatment and relevant risk factors to NSAID-induced UGIB in the selected population. Methods This study was a cross-sectional, retrospective, case-series analysis of NSAID-induced UGIB resulting in hospital admission to the Requena General Hospital, Valencia, Spain, occurring from 1997 to 2005. International Classification of Diseases, Ninth Revision, Clinical Modification codes were used to identify UGIB admissions associated with NSAIDs. To estimate the probability of association between UGIB and the use of NSAIDs, the Naranjo adverse drug reaction probability was used. Patients were categorized as high-risk to develop UGIB if they met ≥1 of the following risk criteria (relevant risk factors): aged ≥65 years (age risk factor); peptic ulcer disease or NSAID gastropathy occurring in the year before their hospital admission (history risk factor); and concomitant use of other NSAIDs, systemic corticoids, oral anticoagulants, or platelet aggregation inhibitors (concomitant medication risk factor). Patients were categorized as candidates to use gastroprotections if they met ≥1 of the relevant risk factors. Patients were categorized as users of gastroprotective treatment if they used proton pump inhibitors, histamine H2-receptor antagonists, or misoprostol at hospital admission. Results This study comprised 209 cases of NSAID-induced UGIB (129 men, 80 women: mean [SD] age, 71.5 [13.8] years; 128 [61.2%] receiving acetyl salicylic acid [ASA], with 72 [34.4%] receiving low

  3. Genetics of gastrointestinal atresias.

    PubMed

    Celli, Jacopo

    2014-08-01

    Gastrointestinal atresias are a common and serious feature within the spectrum of gastrointestinal malformations. Atresias tend to be lethal, although, now-days surgery and appropriate care can restore function to the affected organs. In spite of their frequency, their life threatening condition and report history gastrointestinal atresias' etiology remains mostly unclarified. Gastrointestinal atresias can occur as sporadic but they are more commonly seen in association with other anomalies. For the syndromic cases there is mounting evidence of a strong genetic component. Sporadic cases are generally thought to originate from mechanical or vascular incidents in utero, especially for the atresias of the lower intestinal tract. However, recent data show that a genetic component may be present also in these cases. Embryological and genetic studies are starting to uncover the mechanism of gastrointestinal development and their genetic components. Here we present an overview of the current knowledge of gastrointestinal atresias, their syndromic forms and the genetic pathways involved in gastrointestinal malformation. PMID:25019371

  4. Modeling the Formation of Polyimide Microspheres

    NASA Technical Reports Server (NTRS)

    Pipes, R. B.; Weiser, E. S.; Gonsoulin, B.; Hubert, P.

    2002-01-01

    High temperature polyimide microspheres have been developed from polyimide solid residuum by a simple inflation process. Microspheres have been fabricated from several polyimide precursors through the use of a circulating air oven. Microsphere formation and final physical property characterization have been limited to simple mechanical and thermal testing. The present paper focuses on developing an understanding of microsphere formation through simple geometric rules for an incompressible polymeric material and microscopic observations of precursor residuum inflation. Inflation kinematics of the hollow polyimide microspheres as a function of time and temperature is discussed.

  5. Polarization Dependent Whispering Gallery Modes in Microspheres

    NASA Technical Reports Server (NTRS)

    Adamovsky, Grigory (Inventor); Wrbanek, Susan Y. (Inventor)

    2016-01-01

    A tunable resonant system is provided and includes a microsphere that receives an incident portion of a light beam generated via a light source, the light beam having a fundamental mode, a waveguide medium that transmits the light beam from the light source to the microsphere, and a polarizer disposed in a path of the waveguide between the light source and the microsphere. The incident portion of the light beam creates a fundamental resonance inside the microsphere. A change in a normalized frequency of the wavelength creates a secondary mode in the waveguide and the secondary mode creates a secondary resonance inside the microsphere.

  6. Production of monodisperse, polymeric microspheres

    NASA Technical Reports Server (NTRS)

    Rembaum, Alan (Inventor); Rhim, Won-Kyu (Inventor); Hyson, Michael T. (Inventor); Chang, Manchium (Inventor)

    1990-01-01

    Very small, individual polymeric microspheres with very precise size and a wide variation in monomer type and properties are produced by deploying a precisely formed liquid monomer droplet, suitably an acrylic compound such as hydroxyethyl methacrylate into a containerless environment. The droplet which assumes a spheroid shape is subjected to polymerizing radiation such as ultraviolet or gamma radiation as it travels through the environment. Polymeric microspheres having precise diameters varying no more than plus or minus 5 percent from an average size are recovered. Many types of fillers including magnetic fillers may be dispersed in the liquid droplet.

  7. Porosity-Tuned Chitosan-Polyacrylamide Hydrogel Microspheres for Improved Protein Conjugation.

    PubMed

    Jung, Sukwon; Abel, John H; Starger, Jesse L; Yi, Hyunmin

    2016-07-11

    We report a robust method to manufacture polyacrylamide-based functional hydrogel microspheres with readily tunable macroporous structures by utilizing a simple micromolding-based technique. Specifically, surface tension-induced droplet formation of aqueous solutions of chitosan and acrylamide in 2D-shaped micromolds followed by photoinduced polymerization leads to monodisperse microspheres. Pore sizes of the microspheres can be readily tuned by simple addition of inert long-chain poly(ethylene glycol) porogen at low content in the prepolymer solution. The as-prepared chitosan-polyacrylamide microspheres exhibit chemical functionality through chitosan's primary amines, rapid protein conjugation with selective tetrazine-trans-cyclooctene reaction, and nonfouling property. Combined with the potential to create anisotropic network structures, we envision that our simple fabrication-conjugation method would offer a potent route to manufacture a variety of biofunctionalized hydrogel microentities. PMID:27351270

  8. Highly Sensitive and Reproducible SERS Performance from Uniform Film Assembled by Magnetic Noble Metal Composite Microspheres.

    PubMed

    Niu, Chunyu; Zou, Bingfang; Wang, Yongqiang; Cheng, Lin; Zheng, Haihong; Zhou, Shaomin

    2016-01-26

    To realize highly sensitive and reproducible SERS performance, a new route was put forward to construct uniform SERS film by using magnetic composite microspheres. In the experiment, monodisperse Fe3O4@SiO2@Ag microspheres with hierarchical surface were developed and used as building block of SERS substrate, which not only realized fast capturing analyte through dispersion and collection under external magnet but also could be built into uniform film through magnetically induced self-assembly. By using R6G as probe molecule, the as-obtained uniform film exhibited great improvement on SERS performance in both sensitivity and reproducibility when compared with nonuniform film, demonstrating the perfect integration of high sensitivity of hierarchal noble metal microspheres and high reproducibility of ordered microspheres array. Furthermore, the as-obtained product was used to detect pesticide thiram and also exhibited excellent SERS performance for trace detection. PMID:26731200

  9. Continuous separation of serum proteins using a stirred cell charged with carboxylated and sulfonated microspheres.

    PubMed

    Lee, J H; Yoon, J Y; Kim, W S

    1998-01-01

    We contrived a new separation system using a stirred cell charged with uncoupled microsphere similar to the chromatographic separation. Microspheres, carboxylated PS/PMAA and sulfonated PS/PNaSS, were prepared by emulsifier-free emulsion polymerization. To complement the submicron size weakness and the absence of ligands, we employed the latex form, the dispersion of microsphere, and took advantage of interaction relationships between proteins and microspheres. Adsorption isotherm is contemplated to investigate continuous separation behaviours of serum proteins. Selectivity of separation is in the following order: PS/PNaSS-2.0 (high sulfonated) < PS/PNaSS-0.3 (low sulfonated) < PS/PMAA-0.5 (low carboxylated). Unlike previous works on batch separation, not only the adsorbed amount in equilibrium (Cm), but also adsorption coefficient (K), played an important role in continuous separation. Functional groups (carboxyl and sulfonate), induced from the co-monomer, also affected the adsorption behaviours. PMID:9861492

  10. Gastrointestinal Morbidity in Obesity

    PubMed Central

    Acosta, Andres; Camilleri, Michael

    2014-01-01

    Obesity is a complex disease that results from increased energy intake and decreased energy expenditure. The gastrointestinal system plays a key role in the pathogenesis of obesity and facilitates caloric imbalance. Changes in gastrointestinal hormones and the inhibition of mechanisms that curtail caloric intake result in weight gain. It is not clear if the gastrointestinal role in obesity is a cause or an effect of this disease. Obesity is often associated with type 2 diabetes mellitus (T2DM) and cardiovascular diseases (CVD). Obesity is also associated with gastrointestinal disorders, which are more frequent and present earlier than T2DM and CVD. Diseases such as gastro-esophageal reflux disease, cholelithiasis or non-alcoholic steatohepatitis are directly related to body weight and abdominal adiposity. Our objective is to assess the role of each gastrointestinal organ in obesity and the gastrointestinal morbidity resulting in those organs from effects of obesity. PMID:24602085

  11. Hydration and swelling of amorphous cross-linked starch microspheres.

    PubMed

    Wojtasz, Joanna; Carlstedt, Jonas; Fyhr, Peter; Kocherbitov, Vitaly

    2016-01-01

    Hydration of cross-linked starch microspheres, commercially available as a medical device, was investigated using a multi-method approach. We found that the uptake of water is accompanied by substantial swelling and changes of the polymer structure. Sorption calorimetry provided information about thermodynamics of water sorption, revealed presence of isothermal glass transition and absence of hydration-induced crystallization, observed in non-cross linked starch material. The changes in the surface and bulk properties of microspheres at different water-starch concentrations were investigated using synchrotron radiation X-ray scattering and analyzed using concept of fractals. The obtained information, combined with the results of differential scanning calorimetry, was used to construct a phase diagram of the studied material. Finally, hydration induced evolution of polymer structure revealed by the X-ray scattering was linked to the changes observed during swelling with optical microscopy. PMID:26453872

  12. Development of Risperidone PLGA Microspheres

    PubMed Central

    D'Souza, Susan; Faraj, Jabar A.; Giovagnoli, Stefano; DeLuca, Patrick P.

    2014-01-01

    The aim of this study was to design and evaluate biodegradable PLGA microspheres for sustained delivery of Risperidone, with an eventual goal of avoiding combination therapy for the treatment of schizophrenia. Two PLGA copolymers (50 : 50 and 75 : 25) were used to prepare four microsphere formulations of Risperidone. The microspheres were characterized by several in vitro techniques. In vivo studies in male Sprague-Dawley rats at 20 and 40 mg/kg doses revealed that all formulations exhibited an initial burst followed by sustained release of the active moiety. Additionally, formulations prepared with 50 : 50 PLGA had a shorter duration of action and lower cumulative AUC levels than the 75 : 25 PLGA microspheres. A simulation of multiple dosing at weekly or 15-day regimen revealed pulsatile behavior for all formulations with steady state being achieved by the second dose. Overall, the clinical use of Formulations A, B, C, or D will eliminate the need for combination oral therapy and reduce time to achieve steady state, with a smaller washout period upon cessation of therapy. Results of this study prove the suitability of using PLGA copolymers of varying composition and molecular weight to develop sustained release formulations that can tailor in vivo behavior and enhance pharmacological effectiveness of the drug. PMID:24616812

  13. Conferring Natural-Derived Porous Microspheres with Surface Multifunctionality through Facile Coordination-Enabled Self-Assembly Process.

    PubMed

    Han, Pingping; Shi, Jiafu; Nie, Teng; Zhang, Shaohua; Wang, Xueyan; Yang, Pengfei; Wu, Hong; Jiang, Zhongyi

    2016-03-01

    In this study, multifunctional chitin microspheres are synthesized and utilized as a platform for multiple potential applications in enzyme immobilization, catalytic reduction and adsorption. Porous chitin microspheres with an average diameter of 111.5 μm and a porous architecture are fabricated through a thermally induced phase separation method. Then, the porous chitin microspheres are conferred with surface multifunctionality through facile coordination-enabled self-assembly of tannic acid (TA) and titanium (Ti(IV)) bis(ammonium lactate)dihydroxide (Ti-BALDH). The multipoint hydrogen bonds between TA and chitin microspheres confer the TA-Ti(IV) coating with high adhesion capability to adhere firmly to the surface of the chitin microspheres. In view of the biocompatibility, porosity and surface activity, the multifunctional chitin microspheres are used as carriers for enzyme immobilization. The enzyme-conjugated multifunctional porous microspheres exhibit high catalytic performance (102.8 U·mg(-1) yeast alcohol dehydrogenase). Besides, the multifunctional chitin microspheres also find potential applications in the catalytic reduction (e.g., reduction of silver ions to silver nanoparticles) and efficient adsorption of heavy metal ions (e.g., Pb(2+)) taking advantages of their porosity, reducing capability and chelation property. PMID:26963907

  14. Microspheres and nanoparticles from ultrasound

    NASA Astrophysics Data System (ADS)

    Suh, Won Hyuk

    Improved preparations of various examples of monodispersed, porous, hollow, and core-shell metal and semiconductor nanoparticles or nanowires have been developed. Now titania microspheres and nanoparticles and silica microspheres can be synthesized using an inexpensive high frequency (1.7 MHz) ultrasonic generator (household humidifier; ultrasonic spray pyrolysis; USP). Morphology and pore size of titania microspheres were controlled by the silica to Ti(IV) ratio and silica particle size. Fine tuning the precursor ratio affords sub-50 nm titania nanoparticles as well. In terms of silica microspheres, morphology was controlled by the silica to organic monomer ratio. In liquids irradiated with high intensity ultrasound (20 kHz; HIUS), acoustic cavitation produces high energy chemistry through intense local heating inside the gas phase of collapsing bubbles in the liquid. HIUS and USP confine the chemical reactions to isolated sub-micron reaction zones, but sonochemistry does so in a heated gas phase within a liquid, while USP uses a hot liquid droplet carried by a gas flow. Thus, USP can be viewed as a method of phase-separated synthesis using submicron-sized droplets as isolated chemical reactors for nanomaterial synthesis. While USP has been used to create both titania and silica spheres separately, there are no prior reports of titania-silica composites. Such nanocomposites of metal oxides have been produced, and by further manipulation, various porous structures with fascinating morphologies were generated. Briefly, a precursor solution was nebulized using a commercially available household ultrasonic humidifier (1.7 MHz ultrasound generator), and the resulting mist was carried in a gas stream of air through a quartz glass tube in a hot furnace. After exiting the hot zone, these microspheres are porous or hollow and in certain cases magnetically responsive. In the case of titania microspheres, they are rapidly taken up into the cytoplasm of mammalian cells and

  15. Gastrointestinal nuclear imaging

    SciTech Connect

    Not Available

    1988-01-01

    This book contains paper grouped under the headings of: salivary scintigraphy, abscess detection with radionuclides; pediatric gastroenterology; liver spleen, and miscellaneous GI studies: gastrointestinal.

  16. Gastrointestinal disorders - resources

    MedlinePlus

    Digestive disease - resources; Resources - gastrointestinal disorders ... org American Liver Foundation -- www.liverfoundation.org National Digestive Diseases Information Clearinghouse -- digestive.niddk.nih.gov

  17. Silver Clear Nylon Dressing is Effective in Preventing Radiation-Induced Dermatitis in Patients With Lower Gastrointestinal Cancer: Results From a Phase III Study

    SciTech Connect

    Niazi, Tamim M.; Vuong, Te; Azoulay, Laurant; Marijnen, Corrie; Bujko, Kryzstof; Nasr, Elie; Lambert, Christine; Duclos, Marie; Faria, Sergio; David, Marc; Cummings, Bernard

    2012-11-01

    Purpose: For patients with anal canal and advanced rectal cancer, chemoradiation therapy is a curative modality or an important adjunct to surgery. Nearly all patients treated with chemoradiation experience some degree of radiation-induced dermatitis (RID). Prevention and effective treatment of RID, therefore, is of considerable clinical relevance. The present phase III randomized trial compared the efficacy of silver clear nylon dressing (SCND) with that of standard skin care for these patients. Methods and Materials: A total of 42 rectal or anal canal cancer patients were randomized to either a SCND or standard skin care group. SCND was applied from Day 1 of radiation therapy (RT) until 2 weeks after treatment completion. In the control arm, sulfadiazine cream was applied at the time of skin dermatitis. Printed digital photographs taken 2 weeks prior to, on the last day, and two weeks after the treatment completion were scored by 10 blinded readers, who used the common toxicity scoring system for skin dermatitis. Results: The radiation dose ranged from 50.4 to 59.4 Gy, and there were no differences between the 2 groups. On the last day of RT, when the most severe RID occurs, the mean dermatitis score was 2.53 (standard deviation [SD], 1.17) for the standard and 1.67 (SD, 1.2; P=.01) for the SCND arm. At 2 weeks after RT, the difference was 0.39 points in favor of SCND (P=.39). There was considerable intraclass correlation among the 10 observers. Conclusions: Silver clear nylon dressing is effective in reducing RID in patients with lower gastrointestinal cancer treated with combined chemotherapy and radiation treatment.

  18. The Gastrointestinal Microbiome

    PubMed Central

    Engen, Phillip A.; Green, Stefan J.; Voigt, Robin M.; Forsyth, Christopher B.; Keshavarzian, Ali

    2015-01-01

    The excessive use of alcohol is a global problem causing many adverse pathological health effects and a significant financial health care burden. This review addresses the effect of alcohol consumption on the microbiota in the gastrointestinal tract (GIT). Although data are limited in humans, studies highlight the importance of changes in the intestinal microbiota in alcohol-related disorders. Alcohol-induced changes in the GIT microbiota composition and metabolic function may contribute to the well-established link between alcohol-induced oxidative stress, intestinal hyperpermeability to luminal bacterial products, and the subsequent development of alcoholic liver disease (ALD), as well as other diseases. In addition, clinical and preclinical data suggest that alcohol-related disorders are associated with quantitative and qualitative dysbiotic changes in the intestinal microbiota and may be associated with increased GIT inflammation, intestinal hyperpermeability resulting in endotoxemia, systemic inflammation, and tissue damage/organ pathologies including ALD. Thus, gut-directed interventions, such as probiotic and synbiotic modulation of the intestinal microbiota, should be considered and evaluated for prevention and treatment of alcohol-associated pathologies. PMID:26695747

  19. Paraneoplastic thrombocytosis in gastrointestinal cancer.

    PubMed

    Baranyai, Zsolt; Jósa, Valéria; Tóth, Ambrus; Szilasi, Zsuzsanna; Tihanyi, Balazs; Zaránd, Attila; Harsanyi, Laszlo; Szállási, Zoltán

    2016-06-01

    It has been demonstrated recently in several solid tumors that thrombocytosis at diagnosis may correlate with tumor invasion, metastatic progression and worse outcome. Several details of the pathomechanism of the relationship of thrombocytosis and cancer have been elucidated; however, the complete process is not clearly understood. Several hypotheses have been proposed. Recently, it was suggested that in ovarian cancer elevated IL-6 production by the tumor may induce increased megakaryopoiesis via hepatic thrombopoietin production leading to thrombocytosis. The importance of the prognostic power of elevated platelet count is still debated in gastrointestinal cancer. The aims of this review were to evaluate the prognostic significance of thrombocytosis in gastrointestinal tumors, to see whether clinical practice confirmed the hypotheses and to reveal the causes of the inconsistent findings. PMID:27136385

  20. Gastrointestinal malignancy and the microbiome.

    PubMed

    Abreu, Maria T; Peek, Richard M

    2014-05-01

    Microbial species participate in the genesis of a substantial number of malignancies-in conservative estimates, at least 15% of all cancer cases are attributable to infectious agents. Little is known about the contribution of the gastrointestinal microbiome to the development of malignancies. Resident microbes can promote carcinogenesis by inducing inflammation, increasing cell proliferation, altering stem cell dynamics, and producing metabolites such as butyrate, which affect DNA integrity and immune regulation. Studies in human beings and rodent models of cancer have identified effector species and relationships among members of the microbial community in the stomach and colon that increase the risk for malignancy. Strategies to manipulate the microbiome, or the immune response to such bacteria, could be developed to prevent or treat certain gastrointestinal cancers. PMID:24406471

  1. The Effect of Ergotamine on Tissue Blood Flow and the Arteriovenous Shunting of Radioactive Microspheres in the Head

    PubMed Central

    Johnston, Barbara M.; Saxena, P.R.

    1978-01-01

    1 The radioactive microsphere method was used to study the effects of ergotamine (5, 10 and 20 μg/kg, i.v.) on systemic and regional haemodynamic variables in chloralose-urethane anaesthetized cats. The influence of the drug was also studied on the number of 15 μm microspheres escaping entrapment in the head to emerge in the left external jugular vein. 2 Ergotamine decreased the heart rate and cardiac output. Since arterial blood pressure remained unchanged, calculated total peripheral resistance increased. 3 The regional distribution of cardiac output obtained with 15 μm microspheres agreed well with previous studies in cats where 25 μm spheres were used. The most pronounced difference was that in the present investigation more microspheres, apparently escaping through arteriovenous anastomoses (AVAs), were detected in the lungs than when larger spheres had been used. 4 Coronary blood flow decreased, while uterine blood flow was increased by the drug. The microsphere content of the lungs, which receive the spheres not only via bronchial arteries but also via AVAs, was greatly reduced by all doses of ergotamine. Ergotamine did not influence tissue blood flow to other major organs such as the brain, kidneys, skin, liver, skeletal muscle or the gastrointestinal tract. 5 In the 16 experiments, 0.46 ± 0.05 (s.e. mean)% of the total microspheres injected (equivalent to 11.7 ± 1.4% of microspheres detected in the left-side of the head) appeared within 2 min of microsphere injection into the left external jugular vein. The highest dose of ergotamine significantly reduced the shunting of the microspheres in the head. 6 Since 15 μm microspheres are only likely to reach the lungs by passing into the venous circulation through large glomus-type AVAs, we conclude that ergotamine reduces the fraction of microspheres appearing in the lungs by causing strong vasoconstriction in the AVAs in the head. 7 In conformity with the closure of head AVAs is the finding that

  2. Microsphere coated substrate containing reactive aldehyde groups

    NASA Technical Reports Server (NTRS)

    Rembaum, Alan (Inventor); Yen, Richard C. K. (Inventor)

    1984-01-01

    A synthetic organic resin is coated with a continuous layer of contiguous, tangential, individual microspheres having a uniform diameter preferably between 100 Angstroms and 2000 Angstroms. The microspheres are an addition polymerized polymer of an unsaturated aldehyde containing 4 to 20 carbon atoms and are covalently bonded to the substrate by means of high energy radiation grafting. The microspheres contain reactive aldehyde groups and can form conjugates with proteins such as enzymes or other aldehyde reactive materials.

  3. Glass microspheres for medical applications

    NASA Astrophysics Data System (ADS)

    Conzone, Samuel David

    Radioactive dysprosium lithium borate glass microspheres have been developed as biodegradable radiation delivery vehicles for the radiation synovectomy treatment of rheumatoid arthritis. Once injected into a diseased joint, the microspheres deliver a potent dose of radiation to the diseased tissue, while a non-uniform chemical reaction converts the glass into an amorphous, porous, hydrated dysprosium phosphate reaction product. The non-radioactive, lithium-borate component is dissolved from the glass (up to 94% weight loss), while the radioactive 165Dy reacts with phosphate anions in the body fluids, and becomes "chemically" trapped in a solid, dysprosium phosphate reaction product that has the same size as the un-reacted glass microsphere. Ethylene diamine tetraacetate (EDTA) chelation therapy can be used to dissolve the dysprosium phosphate reaction product after the radiation delivery has subsided. The dysprosium phosphate reaction product, which formed in vivo in the joint of a Sprague-Dawley rat, was dissolved by EDTA chelation therapy in <1 week, without causing any detectable joint damage. The combination of dysprosium lithium borate glass microspheres and EDTA chelation therapy provides an unique "tool" for the medical community, which can deliver a large dose (>100 Gy) of localized beta radiation to a treatment site within the body, followed by complete biodegradability. The non-uniform reaction process is a desirable characteristic for a biodegradable radiation delivery vehicle, but it is also a novel material synthesis technique that can convert a glass to a highly porous materials with widely varying chemical composition by simple, low-temperature, glass/solution reaction. The reaction product formed by nonuniform reaction occupies the same volume as the un-reacted glass, and after drying for 1 h at 300°C, has a specific surface area of ≈200 m2/g, a pore size of ≈30 nm, and a nominal crushing strength of ≈10 MPa. Finally, rhenium glass

  4. Preparation, drug releasing property and pharmacodynamics of soy isoflavone-loaded chitosan microspheres.

    PubMed

    Du, Zhongyan; Dou, Xiaobing; Huang, Chenyun; Gao, Jia; Hu, Linfeng; Zhu, Jiazhen; Qian, Ying; Dou, Minhua; Fan, Chunlei

    2013-01-01

    Soybean isoflavone (SIF) has anti-aging properties and many other biological functions; however, SIF is difficult to reach higher blood concentration due to its rapid metabolism. Therefore, it is of great value to design and produce a sustained-release formulation that is able to maintain a stable level of plasma concentrations. In this paper, soybean isoflavone sustained-release microsphere from chitosan and sodium alginate was prepared successfully. The important factors that determined the quality of the microspheres were the sodium alginate concentration in solution B, the ratio of soybean isoflavone to chitosan and the mixing speed. The relative yield, encapsulation efficiency and drug loading capability of SIF were much higher than the existing commercial formulations. In real gastrointestinal conditions, compared with the non-sustained release group, the release rate of SIF slowed down and the reaction time was prolonged. Animal experiments showed that sustained-release microspheres intensified the anti-aging potentials of SIF. Compared with the Non-sustained release (NSR) group mice, oral SIF/CHI microsphere treated mice were better in the Morris Water Maze Test (MWMT), the MDA level in the both plasma and brain of the sustained release (SR) group mice decreased, and SOD content was remarkably improved. PMID:24244544

  5. Oral Delivery of Exenatide via Microspheres Prepared by Cross-Linking of Alginate and Hyaluronate

    PubMed Central

    Zhang, Baojie; He, Dongyang; Fan, Yu; Liu, Nan; Chen, Yijun

    2014-01-01

    Exenatide is an FDA-approved glucose-lowering peptide drug for the treatment of type 2 diabetes by subcutaneous injection. To address the issues on the inconvenience for patient use and the difficulty of oral administration of peptide drugs, chemical cross-linking of two pH-responsive biomaterials, alginate and hyaluronate, was carried out to prepare a new material for the encapsulation of exenatide as a form of microspheres. The exenatide-loaded microspheres exhibited spherical structures with excellent loading and release behaviors in the simulated gastrointestinal tract environments. After oral administration of the microspheres in db/db mice, maximum plasma concentration of exenatide appeared at 4 hours, and blood glucose was effectively reduced to a normal level within 2 hours and maintained for another 4 hours. The bioavailability of the exenatide-loaded microspheres, relative to subcutaneous injection of exenatide, reached 10.2%. Collectively, the present study demonstrated the feasibility of orally delivering exenatide with the new cross-linked biomaterial and formulation, and showed therapeutic potential for clinical applications. PMID:24465870

  6. Oral delivery of exenatide via microspheres prepared by cross-linking of alginate and hyaluronate.

    PubMed

    Zhang, Baojie; He, Dongyang; Fan, Yu; Liu, Nan; Chen, Yijun

    2014-01-01

    Exenatide is an FDA-approved glucose-lowering peptide drug for the treatment of type 2 diabetes by subcutaneous injection. To address the issues on the inconvenience for patient use and the difficulty of oral administration of peptide drugs, chemical cross-linking of two pH-responsive biomaterials, alginate and hyaluronate, was carried out to prepare a new material for the encapsulation of exenatide as a form of microspheres. The exenatide-loaded microspheres exhibited spherical structures with excellent loading and release behaviors in the simulated gastrointestinal tract environments. After oral administration of the microspheres in db/db mice, maximum plasma concentration of exenatide appeared at 4 hours, and blood glucose was effectively reduced to a normal level within 2 hours and maintained for another 4 hours. The bioavailability of the exenatide-loaded microspheres, relative to subcutaneous injection of exenatide, reached 10.2%. Collectively, the present study demonstrated the feasibility of orally delivering exenatide with the new cross-linked biomaterial and formulation, and showed therapeutic potential for clinical applications. PMID:24465870

  7. Induction of mesenchymal stem cell differentiation and cartilage formation by cross-linker-free collagen microspheres.

    PubMed

    Mathieu, M; Vigier, S; Labour, M N; Jorgensen, C; Belamie, E; Noël, D

    2014-01-01

    Because of poor self-healing ability, joint cartilage can undergo irreversible degradation in the course of various diseases or after injury. A promising approach for cartilage engineering consists of using of mesenchymal stem cells (MSC) and a differentiation factor combined with an injectable carrier biomaterial. We describe here a novel synthesis route for native collagen microspheres that does not involve the use of potentially toxic crosslinking agents. An emulsion was formed between a type I collagen solution and perfluorinated oil, stabilised by a biocompatible triblock perfluorinated copolymer surfactant. Spherical microparticles of fibrillar collagen were formed through a sol-gel transition induced by ammonia vapours. Electron microscopy observations showed that these self-cross-linked microspheres were constituted by a gel of striated collagen fibrils. Microspheres that were loaded with transforming growth factor beta (TGF-β)3 progressively released this differentiation factor over a four weeks period. Human MSC rapidly adhered to TGF-β3-loaded microspheres and, after 21 d of culture, exhibited typical chondrocyte morphology and produced an uncalcified matrix made of the predominant cartilage components, aggrecan and type II collagen, but devoid of the hypertrophic marker type X collagen. Subcutaneous co-injection of MSC and TGF-β3-loaded microspheres in mice consistently led to the formation of a cartilage-like tissue, which was however hypertrophic, calcified and vascularised. In conclusion, we developed cross-linker free collagen microspheres that allowed chondrogenic differentiation of MSC in vitro and in vivo. PMID:25179212

  8. Electrospray synthesis and properties of hierarchically structured PLGA TIPS microspheres for use as controlled release technologies.

    PubMed

    Malik, Salman A; Ng, Wing H; Bowen, James; Tang, Justin; Gomez, Alessandro; Kenyon, Anthony J; Day, Richard M

    2016-04-01

    Microsphere-based controlled release technologies have been utilized for the long-term delivery of proteins, peptides and antibiotics, although their synthesis poses substantial challenges owing to formulation complexities, lack of scalability, and cost. To address these shortcomings, we used the electrospray process as a reproducible, synthesis technique to manufacture highly porous (>94%) microspheres while maintaining control over particle structure and size. Here we report a successful formulation recipe used to generate spherical poly(lactic-co-glycolic) acid (PLGA) microspheres using the electrospray (ES) coupled with a novel thermally induced phase separation (TIPS) process with a tailored Liquid Nitrogen (LN2) collection scheme. We show how size, shape and porosity of resulting microspheres can be controlled by judiciously varying electrospray processing parameters and we demonstrate examples in which the particle size (and porosity) affect release kinetics. The effect of electrospray treatment on the particles and their physicochemical properties are characterized by scanning electron microscopy, confocal Raman microscopy, thermogravimetric analysis and mercury intrusion porosimetry. The microspheres manufactured here have successfully demonstrated long-term delivery (i.e. 1week) of an active agent, enabling sustained release of a dye with minimal physical degradation and have verified the potential of scalable electrospray technologies for an innovative TIPS-based microsphere production protocol. PMID:26803601

  9. Dose-rate distribution of {sup 32}P-glass microspheres for intra-arterial brachytherapy

    SciTech Connect

    Guimaraes, Carla C.; Moralles, Mauricio; Sene, Frank F.; Martinelli, Jose R.

    2010-02-15

    Purpose: The intra-arterial administration of radioactive glass microspheres is an alternative therapy option for treating primary hepatocellular carcinoma, the main cause of liver cancer death, and metastatic liver cancer, another important kind of cancer induced in the liver. The technique involves the administration of radioactive microspheres in the hepatic artery, which are trapped preferentially in the tumor. Methods: In this work the GEANT4 toolkit was used to calculate the radial dose-rate distributions in water from {sup 32}P-loaded glass microspheres and also from {sup 90}Y-loaded glass microspheres. To validate the toolkit for this application, the authors compared the dose-rate distribution of {sup 32}P and {sup 90}Y point sources in water with data from the International Commission on Radiation Units and Measurements report 72. Results: Tables of radial dose-rate distributions are provided for practical use in brachytherapy planning with these microspheres. Conclusions: The simulations with the microspheres show that the shape of the beta ray energy spectra with respect to the {sup 32}P and {sup 90}Y sources is significantly modified by the glass matrix.

  10. Size-dependent optical imaging properties of high-index immersed microsphere lens

    NASA Astrophysics Data System (ADS)

    Guo, Minglei; Ye, Yong-Hong; Hou, Jinglei; Du, Bintao

    2016-03-01

    The imaging properties of high-index immersed microsphere lenses in the diameter range of 5-300 µm are experimentally studied. Our experimental results show that shifting the focal plane of the objective lens can result in different optical properties. When light beams generated from the objective lens are focused near the low surface of the microsphere lens, interference rings can be observed by a conventional optical microscopy, and its diameter and ring number increase with the diameter of microspheres, which can be similarly described by conventional wave optics. When the focal plane of the objective lens is further turned down about several microns, the Blu-ray disk with sub-wavelength structures can be discerned with a magnification up to 4.5 × and field of view up to 14 µm. The image contrast and resolution decrease as the microsphere diameter increases. Calculations of the electric field distributions indicate that the "photonic nanojet" induced by the microsphere performs an important role in sub-wavelength imaging. The surrounding medium can be expected to improve the formation of both the sub-wavelength images and the interference rings. Our studies will help the understanding of the imaging mechanisms in microsphere lenses.

  11. BMP2-loaded hollow hydroxyapatite microspheres exhibit enhanced osteoinduction and osteogenicity in large bone defects

    PubMed Central

    Xiong, Long; Zeng, Jianhua; Yao, Aihua; Tu, Qiquan; Li, Jingtang; Yan, Liang; Tang, Zhiming

    2015-01-01

    The regeneration of large bone defects is an osteoinductive, osteoconductive, and osteogenic process that often requires a bone graft for support. Limitations associated with naturally autogenic or allogenic bone grafts have demonstrated the need for synthetic substitutes. The present study investigates the feasibility of using novel hollow hydroxyapatite microspheres as an osteoconductive matrix and a carrier for controlled local delivery of bone morphogenetic protein 2 (BMP2), a potent osteogenic inducer of bone regeneration. Hollow hydroxyapatite microspheres (100±25 μm) with a core (60±18 μm) and a mesoporous shell (180±42 m2/g surface area) were prepared by a glass conversion technique and loaded with recombinant human BMP2 (1 μg/mg). There was a gentle burst release of BMP2 from microspheres into the surrounding phosphate-buffered saline in vitro within the initial 48 hours, and continued at a low rate for over 40 days. In comparison with hollow hydroxyapatite microspheres without BMP2 or soluble BMP2 without a carrier, BMP2-loaded hollow hydroxyapatite microspheres had a significantly enhanced capacity to reconstitute radial bone defects in rabbit, as shown by increased serum alkaline phosphatase; quick and complete new bone formation within 12 weeks; and great biomechanical flexural strength. These results indicate that BMP2-loaded hollow hydroxyapatite microspheres could be a potential new option for bone graft substitutes in bone regeneration. PMID:25609957

  12. Patient Selection and Activity Planning Guide for Selective Internal Radiotherapy With Yttrium-90 Resin Microspheres

    SciTech Connect

    Lau, Wan-Yee; Kennedy, Andrew S.; Kim, Yun Hwan; Lai, Hee Kit; Lee, Rheun-Chuan; Leung, Thomas W.T.; Liu, Ching-Sheng; Salem, Riad; Sangro, Bruno; Shuter, Borys; Wang, Shih-Chang

    2012-01-01

    Purpose: Selective internal radiotherapy (SIRT) with yttrium-90 ({sup 90}Y) resin microspheres can improve the clinical outcomes for selected patients with inoperable liver cancer. This technique involves intra-arterial delivery of {beta}-emitting microspheres into hepatocellular carcinomas or liver metastases while sparing uninvolved structures. Its unique mode of action, including both {sup 90}Y brachytherapy and embolization of neoplastic microvasculature, necessitates activity planning methods specific to SIRT. Methods and Materials: A panel of clinicians experienced in {sup 90}Y resin microsphere SIRT was convened to integrate clinical experience with the published data to propose an activity planning pathway for radioembolization. Results: Accurate planning is essential to minimize potentially fatal sequelae such as radiation-induced liver disease while delivering tumoricidal {sup 90}Y activity. Planning methods have included empiric dosing according to degree of tumor involvement, empiric dosing adjusted for the body surface area, and partition model calculations using Medical Internal Radiation Dose principles. It has been recommended that at least two of these methods be compared when calculating the microsphere activity for each patient. Conclusions: Many factors inform {sup 90}Y resin microsphere SIRT activity planning, including the therapeutic intent, tissue and vasculature imaging, tumor and uninvolved liver characteristics, previous therapies, and localization of the microsphere infusion. The influence of each of these factors has been discussed.

  13. Coupling system to a microsphere cavity

    NASA Technical Reports Server (NTRS)

    Iltchenko, Vladimir (Inventor); Maleki, Lute (Inventor); Yao, Steve (Inventor); Wu, Chi (Inventor)

    2002-01-01

    A system of coupling optical energy in a waveguide mode, into a resonator that operates in a whispering gallery mode. A first part of the operation uses a fiber in its waveguide mode to couple information into a resonator e.g. a microsphere. The fiber is cleaved at an angle .PHI. which causes total internal reflection within the fiber. The energy in the fiber then forms an evanescent field and a microsphere is placed in the area of the evanescent field. If the microsphere resonance is resonant with energy in the fiber, then the information in the fiber is effectively transferred to the microsphere.

  14. Compression molding of aerogel microspheres

    DOEpatents

    Pekala, R.W.; Hrubesh, L.W.

    1998-03-24

    An aerogel composite material produced by compression molding of aerogel microspheres (powders) mixed together with a small percentage of polymer binder to form monolithic shapes in a cost-effective manner is disclosed. The aerogel composites are formed by mixing aerogel microspheres with a polymer binder, placing the mixture in a mold and heating under pressure, which results in a composite with a density of 50--800 kg/m{sup 3} (0.05--0.80 g/cc). The thermal conductivity of the thus formed aerogel composite is below that of air, but higher than the thermal conductivity of monolithic aerogels. The resulting aerogel composites are attractive for applications such as thermal insulation since fabrication thereof does not require large and expensive processing equipment. In addition to thermal insulation, the aerogel composites may be utilized for filtration, ICF target, double layer capacitors, and capacitive deionization. 4 figs.

  15. Compression molding of aerogel microspheres

    DOEpatents

    Pekala, Richard W.; Hrubesh, Lawrence W.

    1998-03-24

    An aerogel composite material produced by compression molding of aerogel microspheres (powders) mixed together with a small percentage of polymer binder to form monolithic shapes in a cost-effective manner. The aerogel composites are formed by mixing aerogel microspheres with a polymer binder, placing the mixture in a mold and heating under pressure, which results in a composite with a density of 50-800 kg/m.sup.3 (0.05-0.80 g/cc). The thermal conductivity of the thus formed aerogel composite is below that of air, but higher than the thermal conductivity of monolithic aerogels. The resulting aerogel composites are attractive for applications such as thermal insulation since fabrication thereof does not require large and expensive processing equipment. In addition to thermal insulation, the aerogel composites may be utilized for filtration, ICF target, double layer capacitors, and capacitive deionization.

  16. Microspheres in Plasma Display Panels

    NASA Technical Reports Server (NTRS)

    2006-01-01

    Filling small bubbles of molten glass with gases is just as difficult as it sounds, but the technical staff at NASA is not known to shy away from a difficult task. When Microsphere Systems, Inc. (MSI), of Ypsilanti, Michigan, and Imaging Systems Technology, Inc. (IST), of Toledo, Ohio, were trying to push the limits of plasma displays but were having difficulty with the designs, NASA s Glenn Garrett Morgan Commercialization Initiative (GMCI) assembled key personnel at Glenn Research Center and Ohio State University for a brainstorming session to come up with a solution for the companies. They needed a system that could produce hollow, glass micro-sized spheres (microspheres) that could be filled with a variety of gasses. But the extremely high temperature required to force the micro-sized glass bubbles to form at the tip of a metal nozzle resulted in severe discoloration of the microspheres. After countless experiments on various glass-metal combinations, they had turned to the GMCI for help. NASA experts in advanced metals, ceramics, and glass concluded that a new design approach was necessary. The team determined that what was needed was a phosphate glass composition that would remain transparent, and they went to work on a solution. Six weeks later, using the design tips from the NASA team, Tim Henderson, president of MSI, had designed a new system in which all surfaces in contact with the molten glass would be ceramic instead of metal. Meanwhile, IST was able to complete a Phase I Small Business Innovation Research (SBIR) grant supported by the National Science Foundation (NSF) and supply a potential customer with samples of the microspheres for evaluation as filler materials for high-performance insulations.

  17. [Nutrition and gastrointestinal intolerance].

    PubMed

    Madl, C; Holzinger, U

    2013-06-01

    The functional integrity of the gastrointestinal tract is an essential prerequisite in intensive care patients for the sufficient administration of enteral nutrition. Up to 65% of patients in intensive care units develop symptoms of gastrointestinal dysfunction with high residual gastric volume, vomiting and abdominal distension. The pathophysiological alterations of gastrointestinal intolerance and the subsequent effect on the tolerance of enteral nutrition can affect the whole gastrointestinal tract. Gastroduodenal motility disorders in particular, with increased gastroesophageal reflux lead to intolerance. In more than 90% of intensive care patients with gastrointestinal motility disorders an adequate postpyloric enteral nutrition can be carried out using a jejunal tube. In addition to improved tolerance of enteral nutrition this leads to a reduction of gastroesophageal reflux and the incidence of ventilation-associated pneumonia. Apart from the possibility of endoscopic application of the jejunal tube, alternative techniques were developed which allow a faster positioning of the jejunal tube with less complications. Furthermore, there are therapeutic options for improvement of gastrointestinal motility disorders and apart from general measures, also medicinal options for treatment of gastrointestinal intolerance which allow a sufficient enteral nutrition for intensive care patients. PMID:23740106

  18. A pilot-scale study of Cryptosporidium-sized microsphere removals from swimming pools via sand filtration.

    PubMed

    Lu, Ping; Amburgey, James E

    2016-02-01

    Cryptosporidium species are the most common cause of gastrointestinal illness in treated recreational water venues. In order to protect public health during swimming, Cryptosporidium-sized microsphere removals by high-rate sand filtration with six coagulants were evaluated with a 5.5 m(3) pilot-scale swimming pool. A sand filter without coagulation removed 20-63% of Cryptosporidium-sized microspheres. Cryptosporidium-sized microsphere removals exceeded 98% by sand filtration with five of the six tested coagulants. Continuously feeding coagulants A, B, and F (i.e., organic polymers) led to coagulant accumulation in the system and decreased removals over time (<2 days). Coagulant E (polyaluminum chloride) consistently removed more than 90% of microspheres at 30 m/h while the removals dropped to approximately 50% at a filtration rate of 37 m/h. Coagulant C was a chitosan-based product that removed fewer microspheres compared with other products, <75%, under the studied conditions. Results indicated aluminum-based coagulants (coagulants D and E) had an overall performance advantage over the organic polymer based coagulants primarily in terms of their tendency not to accumulate in the water and cease to be effective at improving filter efficiency. PMID:26837835

  19. Gastrointestinal radiation injury: Prevention and treatment

    PubMed Central

    Shadad, Abobakr K; Sullivan, Frank J; Martin, Joseph D; Egan, Laurence J

    2013-01-01

    With the recent advances in detection and treatment of cancer, there is an increasing emphasis on the efficacy and safety aspects of cancer therapy. Radiation therapy is a common treatment for a wide variety of cancers, either alone or in combination with other treatments. Ionising radiation injury to the gastrointestinal tract is a frequent side effect of radiation therapy and a considerable proportion of patients suffer acute or chronic gastrointestinal symptoms as a result. These side effects often cause morbidity and may in some cases lower the efficacy of radiotherapy treatment. Radiation injury to the gastrointestinal tract can be minimised by either of two strategies: technical strategies which aim to physically shift radiation dose away from the normal intestinal tissues, and biological strategies which aim to modulate the normal tissue response to ionising radiation or to increase its resistance to it. Although considerable improvement in the safety of radiotherapy treatment has been achieved through the use of modern optimised planning and delivery techniques, biological techniques may offer additional further promise. Different agents have been used to prevent or minimize the severity of gastrointestinal injury induced by ionising radiation exposure, including biological, chemical and pharmacological agents. In this review we aim to discuss various technical strategies to prevent gastrointestinal injury during cancer radiotherapy, examine the different therapeutic options for acute and chronic gastrointestinal radiation injury and outline some examples of research directions and considerations for prevention at a pre-clinical level. PMID:23345942

  20. Gastrointestinal Parasitic Infections

    PubMed Central

    Embil, Juan A.; Embil, John M.

    1988-01-01

    This article surveys the most important gastrointestinal parasites that affect humans. The modes of acquisition, pathology, epidemiology, diagnosis, and treatment are all briefly examined. Gastrointestinal parasites have become increasingly important in the differential diagnosis of gastrointestinal disease, as a result of a number of circumstances. These circumstances include: increasing travel to developing countries; increased numbers, for one reason or another, of immunocompromised individuals; increased consumption of raw or partially cooked ethnic delicacies; more crowding in day-care centres; increased immigration from developing countries; and an endemic pocket of individuals with certain unhygienic or unsanitary practices. PMID:21253148

  1. Cannabinoids and the gastrointestinal tract

    PubMed Central

    PERTWEE, R

    2001-01-01

    The enteric nervous system of several species, including the mouse, rat, guinea pig and humans, contains cannabinoid CB1 receptors that depress gastrointestinal motility, mainly by inhibiting ongoing contractile transmitter release. Signs of this depressant effect are, in the whole organism, delayed gastric emptying and inhibition of the transit of non-absorbable markers through the small intestine and, in isolated strips of ileal tissue, inhibition of evoked acetylcholine release, peristalsis, and cholinergic and non-adrenergic non-cholinergic (NANC) contractions of longitudinal or circular smooth muscle. These are contractions evoked electrically or by agents that are thought to stimulate contractile transmitter release either in tissue taken from morphine pretreated animals (naloxone) or in unpretreated tissue (γ-aminobutyric acid and 5-hydroxytryptamine). The inhibitory effects of cannabinoid receptor agonists on gastric emptying and intestinal transit are mediated to some extent by CB1 receptors in the brain as well as by enteric CB1 receptors. Gastric acid secretion is also inhibited in response to CB1 receptor activation, although the detailed underlying mechanism has yet to be elucidated. Cannabinoid receptor agonists delay gastric emptying in humans as well as in rodents and probably also inhibit human gastric acid secretion. Cannabinoid pretreatment induces tolerance to the inhibitory effects of cannabinoid receptor agonists on gastrointestinal motility. Findings that the CB1 selective antagonist/inverse agonist SR141716A produces in vivo and in vitro signs of increased motility of rodent small intestine probably reflect the presence in the enteric nervous system of a population of CB1 receptors that are precoupled to their effector mechanisms. SR141716A has been reported not to behave in this manner in the myenteric plexus-longitudinal muscle preparation (MPLM) of human ileum unless this has first been rendered cannabinoid tolerant. Nor has it been

  2. Gastrointestinal food allergy in infants.

    PubMed

    Morita, Hideaki; Nomura, Ichiro; Matsuda, Akio; Saito, Hirohisa; Matsumoto, Kenji

    2013-09-01

    Food allergies are classified into three types, "IgE-mediated," "combined IgE- and cell-mediated" and "cell-mediated/non-IgE-mediated," depending on the involvement of IgE in their pathogenesis. Patients who develop predominantly cutaneous and/or respiratory symptoms belong to the IgE-mediated food allergy type. On the other hand, patients with gastrointestinal food allergy (GI allergy) usually develop gastrointestinal symptoms several hours after ingestion of offending foods; they belong to the cell-mediated/non-IgE-mediated or combined IgE- and cell-mediated food allergy types. GI allergies are also classified into a number of different clinical entities: food protein-induced enterocolitis syndrome (FPIES), food protein-induced proctocolitis (FPIP), food protein-induced enteropathy (Enteropathy) and eosinophilic gastrointestinal disorders (EGID). In the case of IgE-mediated food allergy, the diagnostic approaches and pathogenic mechanisms are well characterized. In contrast, the diagnostic approaches and pathogenic mechanisms of GI allergy remain mostly unclear. In this review, we summarized each type of GI allergy in regard to its historical background and updated clinical features, offending foods, etiology, diagnosis, examinations, treatment and pathogenesis. There are still many problems, especially in regard to the diagnostic approaches for GI allergy, that are closely associated with the definition of each disease. In addition, there are a number of unresolved issues regarding the pathogenic mechanisms of GI allergy that need further study and elucidation. Therefore, we discussed some of the diagnostic and research issues for GI allergy that need further investigation. PMID:23974876

  3. MRI traceability of superparamagnetic iron oxide nanoparticle-embedded chitosan microspheres as an embolic material in rabbit uterus

    PubMed Central

    Choi, Sun Young; Kwak, Byung Kook; Shim, Hyung Jin; Lee, Jaehwi; Hong, Soon Uk; Kim, Kyung Ah

    2015-01-01

    PURPOSE We aimed to compare polyvinyl alcohol (PVA) particles with calibrated superparamagnetic iron oxide (SPIO) nanoparticle-loaded chitosan microspheres in a rabbit model, specifically regarding the relative distribution of embolic agents within the uterus based on magnetic resonance imaging (MRI) and pathological evaluation. METHODS Twelve New Zealand white rabbits underwent uterine artery embolization using either standard PVA particles (45–150 µm or 350–500 µm) or calibrated SPIO-embedded chitosan microspheres (45–150 µm or 300–500 µm). MRI and histopathological findings were compared one week after embolization. RESULTS Calibrated SPIO-loaded chitosan microspheres 45–150 µm in size were detected on T2-weighted images. On histological analysis, calibrated SPIO-embedded chitosan microspheres were found in both myometrium and endometrium, whereas PVA particles were found only in the perimyometrium or extrauterine fat pads. A proportional relationship was noted between the calibrated SPIO-embedded chitosan microsphere size and the size of the occluded artery. CONCLUSION Calibrated SPIO-embedded chitosan microspheres induced greater segmental arterial occlusion than PVA particles and showed great potential as a new embolic material. SPIO-embedded chitosan microspheres can be used to follow distribution of embolic particles through MRI studies. PMID:25333216

  4. Magnetically separable and recyclable Fe3O4-polydopamine hybrid hollow microsphere for highly efficient peroxidase mimetic catalysts.

    PubMed

    Liu, Shujun; Fu, Jianwei; Wang, Minghuan; Yan, Ya; Xin, Qianqian; Cai, Lu; Xu, Qun

    2016-05-01

    Magnetic Fe3O4-polydopamine (PDA) hybrid hollow microspheres, in which Fe3O4 nanoparticles were firmly incorporated in the cross-linked PDA shell, have been prepared through the formation of core/shell PS/Fe3O4-PDA composites based on template-induced covalent assembly method, followed by core removal in a tetrahydrofuran solution. The morphology, composition, thermal property and magnetic property of the magnetic hybrid hollow microspheres were characterized by SEM, TEM, FT-IR, XRD, TGA, and vibrating sample magnetometer, respectively. Results revealed that the magnetic hybrid hollow microspheres had about 380 nm of inner diameter and about 30 nm of shell thickness, and 13.6 emu g(-1) of magnetization saturation. More importantly, the Fe3O4-PDA hybrid hollow microspheres exhibited intrinsic peroxidase-like activity, as they could quickly catalyze the oxidation of typical substrates 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of hydrogen peroxide. Compared with PDA/Fe3O4 composites where Fe3O4 nanoparticles were loaded on the surface of PDA microspheres, the stability of Fe3O4-PDA hybrid hollow microspheres was greatly improved. As-prepared magnetic hollow microspheres might open up a new application field in biodetection, biocatalysis, and environmental monitoring. PMID:26871276

  5. Budesonide-loaded guar gum microspheres for colon delivery: preparation, characterization and in vitro/in vivo evaluation.

    PubMed

    Liu, Ye; Zhou, Hong

    2015-01-01

    A novel budesonide (BUD) colon delivery release system was developed by using a natural polysaccharide, guar gum. The rigidity of the microspheres was induced by a chemical cross-linking method utilizing glutaraldehyde as the cross-linker. The mean particle size of the microspheres prepared was found to be 15.21 ± 1.32 µm. The drug loading and entrapment efficiency of the formulation were 17.78% ± 2.31% and 81.6% ± 5.42%, respectively. The microspheres were spherical in shape with a smooth surface, and the size was uniform. The in vitro release profiles indicated that the release of BUD from the microspheres exhibited a sustained release behavior. The model that fitted best for BUD released from the microspheres was the Higuchi kinetic model with a correlation coefficient r = 0.9993. A similar phenomenon was also observed in a pharmacokinetic study. The prolongation of the half-life (t1/2), enhanced residence time (mean residence time, MRT) and decreased total clearance (CL) indicated that BUD microspheres could prolong the acting time of BUD in vivo. In addition, BUD guar gum microspheres are thought to have the potential to maintain BUD concentration within target ranges for a long time, decreasing the side effects caused by concentration fluctuation, ensuring the efficiency of treatment and improving patient compliance by reducing dosing frequency. None of the severe signs, like the appearance of epithelial necrosis and the sloughing of epithelial cells, were detected. PMID:25629228

  6. Budesonide-Loaded Guar Gum Microspheres for Colon Delivery: Preparation, Characterization and in Vitro/in Vivo Evaluation

    PubMed Central

    Liu, Ye; Zhou, Hong

    2015-01-01

    A novel budesonide (BUD) colon delivery release system was developed by using a natural polysaccharide, guar gum. The rigidity of the microspheres was induced by a chemical cross-linking method utilizing glutaraldehyde as the cross-linker. The mean particle size of the microspheres prepared was found to be 15.21 ± 1.32 µm. The drug loading and entrapment efficiency of the formulation were 17.78% ± 2.31% and 81.6% ± 5.42%, respectively. The microspheres were spherical in shape with a smooth surface, and the size was uniform. The in vitro release profiles indicated that the release of BUD from the microspheres exhibited a sustained release behavior. The model that fitted best for BUD released from the microspheres was the Higuchi kinetic model with a correlation coefficient r = 0.9993. A similar phenomenon was also observed in a pharmacokinetic study. The prolongation of the half-life (t1/2), enhanced residence time (mean residence time, MRT) and decreased total clearance (CL) indicated that BUD microspheres could prolong the acting time of BUD in vivo. In addition, BUD guar gum microspheres are thought to have the potential to maintain BUD concentration within target ranges for a long time, decreasing the side effects caused by concentration fluctuation, ensuring the efficiency of treatment and improving patient compliance by reducing dosing frequency. None of the severe signs, like the appearance of epithelial necrosis and the sloughing of epithelial cells, were detected. PMID:25629228

  7. Integrated Cryogenic Experiment (ICE) microsphere investigation

    NASA Technical Reports Server (NTRS)

    Spradley, I.; Read, D.

    1989-01-01

    The main objective is to determine the performance of microsphere insulation in a 0-g environment and compare its performance to reference insulations such as multilayer insulation. The Lockheed Helium Extended-Life Dewar (HELD) is used to provide superfluid-helium cold sink for the experiment. The use of HELD allows the low-g dynamic properties of Passive Orbital Disconnect Struts (PODS) to be characterized and provides a flight demonstration of the PODS system. The thermal performance of microspheres in 1 and 0 g was predicted, a flight experiment was designed to determine microsphere thermal performance, and the interface was also designed between the experimental package and the shuttle through HELD and the Hitchhiker-M carrier. A single test cell was designed and fabricated. The cell was filled with uncoated glass microspheres and tested with a liquid-nitrogen cold sink. The data were found to agree with predictions of microsphere performance in 1 g.

  8. Polymer microspheres carrying fluorescent DNA probes

    NASA Astrophysics Data System (ADS)

    Chen, Xiaoyu; Dai, Zhao; Zhang, Jimei; Xu, Shichao; Wu, Chunrong; Zheng, Guo

    2010-07-01

    A polymer microspheres carried DNA probe, which was based on resonance energy transfer, was presented in this paper when CdTe quantum dots(QDs) were as energy donors, Au nanoparticles were as energy accepters and poly(4- vinylpyrindine-co-ethylene glycol dimethacrylate) microspheres were as carriers. Polymer microspheres with functional group on surfaces were prepared by distillation-precipitation polymerization when ethylene glycol dimethacrylate was as crosslinker in acetonitrile. CdTe QDs were prepared when 3-mercaptopropionic acid(MPA) was as the stabilizer in aqueous solution. Because of the hydrogen-bonding between the carboxyl groups of MPA on QDs and the pyrindine groups on the microspheres, the QDs were self-assembled onto the surfaces of microspheres. Then, the other parts of DNA probe were finished according to the classic method. The DNA detection results indicated that this novel fluorescent DNA probe system could recognize the existence of complementary target DNA or not.

  9. Multiplexed Microsphere Suspension Array-Based Immunoassays.

    PubMed

    Lin, Andrew; Salvador, Alexandra; Carter, J Mark

    2015-01-01

    ELISA is an extremely powerful tool to detect analytes because of its sensitivity, selectivity, reproducibility and ease of use. Here we describe sandwich immunoassays performed in suspension on spectrally unique microspheres developed by Luminex. Luminex assays offer the benefit of multiplex analysis of large numbers of analytes in a single reaction. Because the microspheres are spectrally unique, many microspheres, each attached to various antibodies, can be added to a single sample. Luminex instruments can distinguish each microsphere and detect the intensity of a reporter signal for each microsphere. Results are reported in Median Fluorescent Intensities for each analyte. Luminex assays can be used to detect up to 500 analytes in a high-throughput format. Luminex refers to this technology as xMAP(®). Here we describe a routine protocol for a Luminex immunoassay. Other Luminex assays would have to be optimized for specific conditions according to their use. PMID:26160569

  10. Integrated Cryogenic Experiment (ICE) microsphere investigation

    SciTech Connect

    Spradley, I.; Read, D.

    1989-09-01

    The main objective is to determine the performance of microsphere insulation in a 0-g environment and compare its performance to reference insulations such as multilayer insulation. The Lockheed Helium Extended-Life Dewar (HELD) is used to provide superfluid-helium cold sink for the experiment. The use of HELD allows the low-g dynamic properties of Passive Orbital Disconnect Struts (PODS) to be characterized and provides a flight demonstration of the PODS system. The thermal performance of microspheres in 1 and 0 g was predicted, a flight experiment was designed to determine microsphere thermal performance, and the interface was also designed between the experimental package and the shuttle through HELD and the Hitchhiker-M carrier. A single test cell was designed and fabricated. The cell was filled with uncoated glass microspheres and tested with a liquid-nitrogen cold sink. The data were found to agree with predictions of microsphere performance in 1 g.

  11. Gas foamed open porous biodegradable polymeric microspheres.

    PubMed

    Kim, Taek Kyoung; Yoon, Jun Jin; Lee, Doo Sung; Park, Tae Gwan

    2006-01-01

    Highly open porous biodegradable polymeric microspheres were fabricated for use as injectable scaffold microcarriers for cell delivery. A modified water-in-oil-in-water (W1/O/W2) double emulsion solvent evaporation method was employed for producing the microspheres. The incorporation of an effervescent salt, ammonium bicarbonate, in the primary W1 droplets spontaneously produced carbon dioxide and ammonia gas bubbles during the solvent evaporation process, which not only stabilized the primary emulsion, but also created well inter-connected pores in the resultant microspheres. The porous microspheres fabricated under various gas foaming conditions were characterized. The surface pores became as large as 20 microm in diameter with increasing the concentration of ammonium bicarbonate, being sufficient enough for cell infiltration and seeding. These porous scaffold microspheres could be potentially utilized for cultivating cells in a suspension manner and for delivering the seeded cells to the tissue defect site in an injectable manner. PMID:16023197

  12. Severe gastrointestinal bleeding.

    PubMed

    Isaacs, K L

    1994-02-01

    Severe gastrointestinal bleeding is a common cause of admission of the elderly to intensive care units. Differentiation between upper and lower gastrointestinal bleeding is made on the basis of history, physical examination, and diagnostic tests. Therapy is based in part on the severity of the bleeding episode and on the cause of the hemorrhage. Therapeutic intervention may involve medical therapy, endoscopic therapy, angiographic therapy, and surgery. Patient outcome is often related to other underlying disease states. PMID:8168017

  13. Gastrointestinal motility and functional gastrointestinal diseases.

    PubMed

    Kusano, Motoyasu; Hosaka, Hiroko; Kawada, Akiyo; Kuribayashi, Shiko; Shimoyama, Yasuyuki; Zai, Hiroaki; Kawamura, Osamu; Yamada, Masanobu

    2014-01-01

    Digestive tract motility patterns are closely related to the pathophysiology of functional gastrointestinal diseases (FGID), and these patterns differ markedly between the interdigestive period and the postprandial period. The characteristic motility pattern in the interdigestive period is so-called interdigestive migrating contraction (IMC). IMCs have a housekeeping role in the intestinal tract, and could also be related to FGID. IMCs arising from the stomach are called gastrointestinal IMCs (GI-IMC), while IMCs arising from the duodenum without associated gastric contractions are called intestinal IMCs (I-IMC). It is thought that I-IMCs are abnormal in FGID. Transport of food residue to the duodenum via gastric emptying is one of the most important postprandial functions of the stomach. In patients with functional dyspepsia (FD), abnormal gastric emptying is a possible mechanism of gastric dysfunction. Accordingly, delayed gastric emptying has attracted attention, with prokinetic agents and herbal medicines often being administered in Japan to accelerate gastric emptying in patients who have anorexia associated with dyspepsia. Recently, we found that addition of monosodium L-glutamate (MSG) to a high-calorie liquid diet rich in casein promoted gastric emptying in healthy men. Therefore, another potential method of improving delayed gastric emptying could be activation of chemosensors that stimulate the autonomic nervous system of the gastrointestinal tract, suggesting a role for MSG in the management of delayed gastric emptying in patients with FD. PMID:23886379

  14. Phase behavior, structure, and properties of colloidal microsphere-nanoparticle mixtures

    NASA Astrophysics Data System (ADS)

    Tohver, Valeria

    2001-10-01

    We have studied the phase behavior, structure and properties of binary mixtures of negligibly charged colloidal microspheres and highly repulsive nanoparticles. The interactions between such species were investigated via scanning angle reflectometry, zeta potential measurements, and sedimentation studies. At pH < 3, the nanoparticles are highly charged with an estimated zeta potential of 65 mV and the colloidal microspheres are negligibly charged with a measured zeta potential of roughly 1 mV. Under these conditions, scanning angle reflectometry measurements indicated no nanoparticle adsorption occurs on model silica surfaces (i.e., oxidized silicon wafers). However, zeta potential measurements carried out on dilute microsphere suspensions revealed that these microspheres exhibited an effective charge buildup as a function of nanoparticle volume fraction at pH = 1.5. This behavior which we refer to as nanoparticle haloing can stem solely from their repulsive interactions in solution and has a profound effect on the phase behavior, structure and properties of these binary mixtures. The phase behavior, structure, and properties of binary mixtures of negligibly charged colloidal microspheres were studied for two size ratios of 95 and 197 at pH = 1.5. In the absence of nanoparticle additions, the system spontaneously assembled into a colloidal gel whose strength increased with microsphere volume fraction. Between a lower and upper critical nanoparticle volume fraction, such binary mixtures formed a stable fluid phase due to nanoparticle haloing. In this concentration regime, colloidal microsphere crystals could be assembled under gravity-driven sedimentation. Confocal microscopy revealed that such crystals exhibited a center-to-center microsphere separation distance of 2 amusphere, where amusphere is the microsphere radius. Above the upper critical nanoparticle volume fraction, depletion flocculation induced by the presence of highly charged nanoparticles in solution

  15. Microsphere-based scaffolds encapsulating chondroitin sulfate or decellularized cartilage.

    PubMed

    Gupta, Vineet; Tenny, Kevin M; Barragan, Marilyn; Berkland, Cory J; Detamore, Michael S

    2016-09-01

    Extracellular matrix materials such as decellularized cartilage (DCC) and chondroitin sulfate (CS) may be attractive chondrogenic materials for cartilage regeneration. The goal of the current study was to investigate the effects of encapsulation of DCC and CS in homogeneous microsphere-based scaffolds, and to test the hypothesis that encapsulation of these extracellular matrix materials would induce chondrogenesis of rat bone marrow stromal cells. Four different types of homogeneous scaffolds were fabricated from microspheres of poly(D,L-lactic-co-glycolic acid): Blank (poly(D,L-lactic-co-glycolic acid) only; negative control), transforming growth factor-β3 encapsulated (positive control), DCC encapsulated, and CS encapsulated. These scaffolds were then seeded with rat bone marrow stromal cells and cultured for 6 weeks. The DCC and CS encapsulation altered the morphological features of the microspheres, resulting in higher porosities in these groups. Moreover, the mechanical properties of the scaffolds were impacted due to differences in the degree of sintering, with the CS group exhibiting the highest compressive modulus. Biochemical evidence suggested a mitogenic effect of DCC and CS encapsulation on rat bone marrow stromal cells with the matrix synthesis boosted primarily by the inherently present extracellular matrix components. An important finding was that the cell seeded CS and DCC groups at week 6 had up to an order of magnitude higher glycosaminoglycan contents than their acellular counterparts. Gene expression results indicated a suppressive effect of DCC and CS encapsulation on rat bone marrow stromal cell chondrogenesis with differences in gene expression patterns existing between the DCC and CS groups. Overall, DCC and CS were easily included in microsphere-based scaffolds; however, there is a requirement to further refine their concentrations to achieve the differentiation profiles we seek in vitro. PMID:27358376

  16. Nuclear fuel microsphere gamma analyzer

    DOEpatents

    Valentine, Kenneth H.; Long, Jr., Ernest L.; Willey, Melvin G.

    1977-01-01

    A gamma analyzer system is provided for the analysis of nuclear fuel microspheres and other radioactive particles. The system consists of an analysis turntable with means for loading, in sequence, a plurality of stations within the turntable; a gamma ray detector for determining the spectrum of a sample in one section; means for analyzing the spectrum; and a receiver turntable to collect the analyzed material in stations according to the spectrum analysis. Accordingly, particles may be sorted according to their quality; e.g., fuel particles with fractured coatings may be separated from those that are not fractured, or according to other properties.

  17. Solid evacuated microspheres of hydrogen

    DOEpatents

    Turnbull, Robert J.; Foster, Christopher A.; Hendricks, Charles D.

    1982-01-01

    A method is provided for producing solid, evacuated microspheres comprised of hydrogen. The spheres are produced by forming a jet of liquid hydrogen and exciting mechanical waves on the jet of appropriate frequency so that the jet breaks up into drops with a bubble formed in each drop by cavitation. The drops are exposed to a pressure less than the vapor pressure of the liquid hydrogen so that the bubble which is formed within each drop expands. The drops which contain bubbles are exposed to an environment having a pressure just below the triple point of liquid hydrogen and they thereby freeze giving solid, evacuated spheres of hydrogen.

  18. Solvothermal synthesis of three-dimensional microspherical bismuth oxychloride self-assembled by microspheres

    NASA Astrophysics Data System (ADS)

    Li, Tengfei; Lin, Liyang; Wei, Hongmei; Liang, Guoqiang; Kuang, Xinliang; Liu, Tianmo

    2016-02-01

    Uniform BiOCl microspheres have been synthesized via a facile solvothermal route. The structural features of the as-prepared BiOCl samples were systematically characterized by the X-ray powder diffraction (XRD), and field emission scanning electron microscopy (FE-SEM). The SEM characterization results indicated that BiOCl microspheres possessed a superstructure composed of several hierarchical microspheres, which were assembled by numerous two dimensional nanosheets. This kind of special BiOCl 3D microstructure exhibited a large BET surface area of about 14.24 m2 g-1. Besides, the photocatalytic properties of BiOCl hollow microsphere sample and sheet-like sample were investigated in detail. Significantly, BiOCl hollow microsphere sample presented faster degradation rate toward RhB even under visible light, which should be attributed to the unique BiOCl nanosheets self-assembled hollow microspheres.

  19. Bisphosphonate release profiles from magnetite microspheres.

    PubMed

    Miyazaki, Toshiki; Inoue, Tatsuya; Shirosaki, Yuki; Kawashita, Masakazu; Matsubara, Takao; Matsumine, Akihiko

    2014-10-01

    Hyperthermia has been suggested as a novel, minimally invasive cancer treatment method. After implantation of magnetic nano- or microparticles around a tumour through blood vessels, irradiation with alternating magnetic fields facilitates the efficient in situ hyperthermia even for deep-seated tumours. On the basis of this idea, if the microspheres are capable of delivering drugs, they could be promising multifunctional biomaterials effective for chemotherapy as well as hyperthermia. In the present study, magnetite microspheres were prepared by aggregation of the iron oxide colloid in water-in-oil (W/O) emulsion. The release behaviour of alendronate, a typical bisphosphonate, from the microspheres was examined in vitro as a model of the bone tumour prevention and treatment system. The alendronate was successfully incorporated onto the porous magnetite microspheres in vacuum conditions. The drug-loaded microspheres maintained their original spherical shapes even after shaking in ultrapure water for 3 days, suggesting that they have sufficient mechanical integrity for clinical use. It was attributed to high aggregation capability of the magnetite nanoparticles through van der Waals and weak magnetic attractions. The microspheres showed slow release of the alendronate in vitro, resulting from tight covalent or ionic interaction between the magnetite and the alendronate. The release rate was diffusion-controlled type and well controlled by the alendronate concentration in drug incorporation to the microspheres. PMID:24854985

  20. Seeing is believing, PLGA microsphere degradation revealed in PLGA microsphere/PVA hydrogel composites.

    PubMed

    Gu, Bing; Sun, Xuanhao; Papadimitrakopoulos, Fotios; Burgess, Diane J

    2016-04-28

    The aim of this study was to understand the polymer degradation and drug release mechanism from PLGA microspheres embedded in a PVA hydrogel. Two types of microspheres were prepared with different molecular weight PLGA polymers (approximately 25 and 7kDa) to achieve different drug release profiles, with a 9-day lag phase and without a lag phase, respectively. The kinetics of water uptake into the microspheres coincided with the drug release profiles for both formulations. For the 25kDa microspheres, minimal water uptake was observed in the early part of the lag phase followed by substantial water uptake at the later stages and in the drug release phase. For the 7kDa microspheres, water uptake occurred simultaneously with drug release. Water uptake was approximately 2-3 times that of the initial microsphere weight for both formulations. The internal structure of the PLGA microspheres was evaluated using low temperature scanning electron microscopy (cryo-SEM). Burst drug release occurred followed by pore forming from the exterior to the core of both microspheres. A well-defined hydrogel/microsphere interface was observed. For the 25kDa microspheres, internal pore formation and swelling occurred before the second drug release phase. The surface layer of the microspheres remained intact whereas swelling, and degradation of the core continued throughout the drug release period. In addition, microsphere swelling reduced glucose transport through the coatings in PBS media and this was considered to be a as a consequence of the increased thickness of the coatings. The combination of the swelling and microdialysis results provides a fresh understanding on the competing processes affecting molecular transport of bioanalytes (i.e. glucose) through these composite coatings during prolonged exposure in PBS. PMID:26965956

  1. Commonly used gastrointestinal drugs.

    PubMed

    Aggarwal, Annu; Bhatt, Mohit

    2014-01-01

    This chapter reviews the spectrum and mechanisms of neurologic adverse effects of commonly used gastrointestinal drugs including antiemetics, promotility drugs, laxatives, antimotility drugs, and drugs for acid-related disorders. The commonly used gastrointestinal drugs as a group are considered safe and are widely used. A range of neurologic complications are reported following use of various gastrointestinal drugs. Acute neurotoxicities, including transient akathisias, oculogyric crisis, delirium, seizures, and strokes, can develop after use of certain gastrointestinal medications, while disabling and pervasive tardive syndromes are described following long-term and often unsupervised use of phenothiazines, metoclopramide, and other drugs. In rare instances, some of the antiemetics can precipitate life-threatening extrapyramidal reactions, neuroleptic malignant syndrome, or serotonin syndrome. In contrast, concerns about the cardiovascular toxicity of drugs such as cisapride and tegaserod have been grave enough to lead to their withdrawal from many world markets. Awareness and recognition of the neurotoxicity of gastrointestinal drugs is essential to help weigh the benefit of their use against possible adverse effects, even if uncommon. Furthermore, as far as possible, drugs such as metoclopramide and others that can lead to tardive dyskinesias should be used for as short time as possible, with close clinical monitoring and patient education. PMID:24365343

  2. Electrorotation of titanium microspheres.

    PubMed

    Arcenegui, Juan J; Ramos, Antonio; García-Sánchez, Pablo; Morgan, Hywel

    2013-04-01

    Electrorotation (ROT) data for solid titanium micrometer-sized spheres in an electrolyte are presented for three different ionic conductivities, over the frequency range of 10 Hz to 100 kHz. The direction of rotation was found to be opposite to the direction of rotation of the electric field vector (counterfield electrorotation), with a single rotation peak. The maximum rotation rate occurs at a frequency of the order of the reciprocal RC time constant for charging the particle double layer capacitance through the resistor of the electrolyte bulk. A model for the electrical torque acting on a metallic sphere is presented, using a constant phase element impedance to describe the metal/electrolyte interface. The titanium spheres are much denser than the electrolyte and rest on the bottom substrate. Therefore, the electrical and viscous torques near a wall are considered in the analysis. Good agreement is found between the predicted and measured rotational speed as a function of frequency. Theory shows that there is no effect of induced charge electroosmotic flow on the ROT, as observed experimentally. PMID:23348799

  3. Controlled release of imatinib mesylate from PLGA microspheres inhibit craniopharyngioma mediated angiogenesis.

    PubMed

    Karal-Yilmaz, Oksan; Ozkan, Abdulkadir; Akgun, Emel; Kukut, Manolya; Baysal, Kemal; Avsar, Timucin; Kilic, Turker

    2013-01-01

    Poly(lactic-co-glycolic acid) microspheres loaded with imatinib mesylate has been developed as a new therapeutic strategy to prevent craniopharyngioma recurrence. Microspheres composed of different lactic/glycolic acid ratios, molecular weights and drug compositions were synthesized and loaded with imatinib mesylate by modified double-emulsion/solvent evaporation technique and subsequently characterized by particle-size distribution, scanning electron microscopy, encapsulation efficiency and in vitro drug release. Inhibitory potential of imatinib containing microspheres on tumor neovascularization was investigated on craniopharyngioma tumor samples by rat cornea angiogenesis assay. Results showed that microspheres in different LA:GA ratios [LA:GA 50:50 (G50), 75:25 (G25), 85:15 (G15)] considerably reduced neovascularization induced by recurrent tumor samples in an in vivo angiogenesis assay (P < 0.01). Our data indicate that local delivery of imatinib mesylate to the post-surgical tumoral cavity using biodegradable microspheres may be a promising biologically selective approach to prevent the recurrence of craniopharyngiomas, via inhibition of neovascularization. PMID:23053813

  4. Rutin-loaded chitosan microspheres: Characterization and evaluation of the anti-inflammatory activity.

    PubMed

    Cosco, Donato; Failla, Paola; Costa, Nicola; Pullano, Salvatore; Fiorillo, Antonino; Mollace, Vincenzo; Fresta, Massimo; Paolino, Donatella

    2016-11-01

    Rutin was microencapsulated in a chitosan matrix using the spray-drying technique and the resulting system was investigated. High amounts of rutin were efficiently entrapped within polymeric microspheres, and these microparticles were characterized by a smooth surface and afforded a controlled release of the active compound. The anti-inflammatory activity of rutin-loaded microspheres was investigated in in vitro models of NCTC 2544 and C-28 cells treated with LPS by determining the levels of IL-1β and IL-6. The rutin-loaded microspheres showed an increase of in vitro anti-inflammatory activity with respect to the free active compound. Confocal laser scanning microscopy demonstrated that massive intracellular uptake of the chitosan microspheres took place after a few hours of incubation and that the drug was localized in the cytosol compartment of the treated cells. The improved anti-inflammatory activity of the rutin-loaded microspheres was further confirmed by an in vivo model of carrageenan-induced paw edema. PMID:27516307

  5. Cytotoxicity and antitumour activity of 5-fluorouracil-loaded polyhydroxybutyrate and cellulose acetate phthalate blend microspheres.

    PubMed

    Chaturvedi, Kiran; Tripathi, Santosh Kumar; Kulkarni, Anandrao R; Aminabhavi, Tejraj M

    2013-01-01

    Pharmacokinetics, biodistribution and antitumour activity of 5-fluorouracil (5-FU)-loaded polyhydroxybutyrate (PHB) and cellulose acetate phthalate (CAP) blend microspheres were investigated in chemically induced colorectal cancer in albino male Wistar rats and compared with pristine 5-FU given as a suspension. The microspheres were characterised for particle size, encapsulation efficiency, in vitro release and in vitro cytotoxicity on human HT-29 colon cancer cell line. Spherical particles with a mean size of 44 ± 11 µm were obtained that showed sustained release of 5-FU. A high concentration of 5-FU was achieved in colonic tissues and significant reduction in tumour volume and multiplicity were observed in animals treated with 5-FU-loaded microspheres. The decreased levels of plasma albumin, creatinine, leucocytopenia and thrombocytopenia were observed in animals for 5-FU microspheres compared to the standard 5-FU formulation. The results suggest the extended release of 5-FU from the PHB-CAP blend microspheres in colonic region to enhance the antitumour efficacy. PMID:23078151

  6. Pharmacokinetics, in vitro and in vivo correlation, and efficacy of exenatide microspheres in diabetic rats.

    PubMed

    Li, Xingang; Zhao, Zhigang; Li, Liang; Zhou, Tianyan; Lu, Wei

    2015-01-01

    Modeling and simulation are aimed at achieving information about the behaviors of the drugs without the actual measurements and determination. The purpose of this study was to characterize the in vivo behavior of exenatide microspheres using model-based methods. Exenatide is a glucagon-like peptide-1 agonist medication, belonging to the group of incretin mimetics, approved for the treatment of diabetes mellitus type 2. An oil-in-water solvent evaporation method was used to prepare the exenatide microspheres and their physicochemical features were investigated. After subcutaneous injection of exenatide microspheres to streptozotocin-induced diabetic rats, the exenatide concentrations increased and kept increasing and the blood glucose decreased in all diabetic rats. The in vivo release behavior of exenatide from microspheres was described by a transit compartment model. Based on the transit compartment model, the simulation method was proposed for the description of in vivo release. The in vitro and in vivo correlation (IVIVC) was established by the model-based simulation (R(2) = 0.903) and deconvolution (R(2) = 0.922) methods successfully. Using a transit compartment model to characterize the in vivo exenatide release from microspheres is an acceptable approach, and the IVIVC can be estimated reliably with the model-based simulation method. PMID:24467493

  7. Design of phosphated cross-linked microspheres of bael fruit gum as a biodegradable carrier.

    PubMed

    Mahammed, Nawaz; Gowda, D V; Deshpande, Rohan D; Thirumaleshwar, Shailesh

    2015-01-01

    Present work was aimed at designing of phosphated cross-linked microspheres of bael fruit gum (BFG) by emulsification method using sodium-tri-meta phosphate as a cross-linking agent for treatment of colon cancer using 5-fluorouracil as model drug. Stirring speed was found to be 1,000 rpm for about 5 h to be optimal to obtain reproducible microspheres. It was found that there is an increase in particle size as polymer concentration is increased whereas a reduction in particle size was observed as there is increase in stirring speed. Cross-linked BFG microspheres were successfully prepared by emulsification method. Optimum surfactant concentration was found to be 2 % w/w. Scanning electron microscopy studies showed that the drug-loaded microspheres were non-aggregated and in spherical shape. Differential scanning calorimetry and Fourier transform infrared-spectroscopy studies showed that drug and excipients are compatible. Release studies showed that drug release was more profound in cecal medium induced with enzymes causing degradation of the cross linked BFG than that of the release showed in simulated intestinal fluid. Stability studies showed that there were no significant changes in the drug content and physical appearance of microspheres. PMID:24668152

  8. Endoscopic Gastrointestinal Laser Therapy

    PubMed Central

    Buchi, Kenneth N.

    1985-01-01

    The development of flexible fibers for the delivery of laser energy led to the first endoscopic laser applications in humans in the early 1970s. Since that time, much has been learned about applications throughout the gastrointestinal tract. The risks appear to be minimal. The coagulative effect of laser energy is used to treat gastrointestinal hemorrhage and small, benign mucosal lesions. The ablative effect of the Nd:YAG laser on tissue is used for palliative therapy for malignant gastrointestinal disorders and incisional therapy for anatomic lesions such as strictures or cysts. New laser modalities that potentially can be tuned throughout large segments of the electromagnetic spectrum, new fiber-optic delivery systems with specialized tips and new methods of sensitizing tissue to laser energy all indicate that the endoscopic laser should continue to have many new and innovative applications. ImagesFigure 1.Figure 2.Figure 3. PMID:3911589

  9. Gastrointestinal Stent Update

    PubMed Central

    2010-01-01

    The use of self-expanding metallic stents in the upper gastrointestinal tract, placed under radiologic imaging or endoscopic guidance, is the current treatment of choice for the palliation of malignant gastrointestinal outlet obstructions. Advances in metallic stent design and delivery systems have progressed to the stage where this treatment is now considered a minimally invasive therapy. Metallic stent placement will broaden further into the field of nonsurgical therapy for the gastrointestinal tract. To date, metallic stents placed in the esophagus, gastric outlet, colorectum, and bile ducts are not intended to be curative, but rather to provide a palliative treatment for obstructions. The evolution of metallic stent technology will render such procedures not only palliative but also therapeutic, by enabling local drug delivery, and the use of biodegradable materials will reduce procedure-related complications. PMID:21103290

  10. Injectable Peptide Decorated Functional Nanofibrous Hollow Microspheres to Direct Stem Cell Differentiation and Tissue Regeneration

    PubMed Central

    Zhang, Zhanpeng; Gupte, Melanie J.; Jin, Xiaobing; Ma, Peter X.

    2015-01-01

    Injectable microspheres are attractive stem cell carriers for minimally invasive procedures. For tissue regeneration, the microspheres need to present the critical cues to properly direct stem cell differentiation. In natural extracellular matrix (ECM), growth factors (GFs) and collagen nanofibers provide critical chemical and physical cues. However, there have been no reported technologies that integrate synthetic nanofibers and GFs into injectable microspheres. In this study, we synthesized functional nanofibrous hollow microspheres (FNF-HMS), which can covalently bind GF-mimicking peptides. Two different GF-mimicking peptides, Transforming Growth Factor-β1 mimicking peptide Cytomodulin (CM) and Bone Morphogenetic Protein-2 mimicking peptide P24, were separately conjugated onto the FNF-HMS to induce distinct differentiation pathways of rabbit bone marrow-derived mesenchymal stem cells (BMSCs). While no existing biomaterials were reported to successfully deliver CM to induce chondrogenesis, the developed FNF-HMS were shown to effectively present CM to BMSCs and successfully induced their chondrogenesis for cartilage formation in both in vitro and in vivo studies. In addition, P24 was conjugated onto the newly developed FNF-HMS and was capable of retaining its bioactivity and inducing ectopic bone formation in nude mice. These results demonstrate that the novel FNF-HMS can effectively deliver GF-mimicking peptides to modulate stem cell fate and tissue regeneration. PMID:26069467

  11. Comparison of three dimensional magnetic resonance imaging in conjunction with a blood pool contrast agent and nuclear scintigraphy for the detection of experimentally induced gastrointestinal bleeding

    PubMed Central

    Hilfiker, P; Weishaupt, D; Kacl, G; Hetzer, F; Griff, M; Ruehm, S; Debatin, J

    1999-01-01

    BACKGROUND AND AIMS—To compare the performance of 3D magnetic resonance imaging (MRI) in conjunction with an intravascular contrast agent with that of scintigraphy, with respect to detection and localisation of gastrointestinal haemorrhage in vivo in pigs.
METHODS—Intraluminal bleeding sites were surgically created in the small bowel and colon of six pigs. The animals underwent scintigraphy with 99mTc labelled red blood cells and 3D MRI following administration of an intravascular contrast agent (NC100150) at five minute intervals over 30 minutes. For analysis, the intestinal tract was divided into six segments. Based on the two evaluated methods, each segment was characterised on a five point scale regarding the presence of a bleed. At autopsy, the surgically manipulated bowel segments were inspected for the presence of haemorrhage.
RESULTS—Bleeding was confirmed at autopsy in 18/36 segments. Contrast extravasation with subsequent movement through the bowel could be documented on MRI data sets. All segments were correctly characterised, resulting in 100% sensitivity and specificity for MRI. Based on scintigraphy, interpretation of seven segments (19%) was false (sensitivity/specificity of 78%/72%). Differences in diagnostic performance were evident in the receiver operator characteristic (ROC) analysis, with an area under the MRI curve of 0.99 and under the scintigraphy curve of 0.85.
CONCLUSION—In conjunction with an intravascular contrast agent, 3D MRI permits accurate detection and localisation of gastrointestinal bleeding. The extent and evolution of intestinal bleeding can be determined with repeated data acquisition.


Keywords: gastrointestinal tract; haemorrhage; scintigraphy; magnetic resonance; contrast agent PMID:10486369

  12. Nonvariceal Upper Gastrointestinal Bleeding.

    PubMed

    Rahman, Syed Irfan-Ur; Saeian, Kia

    2016-04-01

    In the intensive care unit, vigilance is needed to manage nonvariceal upper gastrointestinal bleeding. A focused history and physical examination must be completed to identify inciting factors and the need for hemodynamic stabilization. Although not universally used, risk stratification tools such as the Blatchford and Rockall scores can facilitate triage and management. Urgent evaluation for nonvariceal upper gastrointestinal bleeds requires prompt respiratory assessment, and identification of hemodynamic instability with fluid resuscitation and blood transfusions if necessary. Future studies are needed to evaluate the indication, safety, and efficacy of emerging endoscopic techniques. PMID:27016164

  13. Microsphere-chain waveguides: Focusing and transport properties

    SciTech Connect

    Allen, Kenneth W. Astratov, Vasily N.; Darafsheh, Arash; Abolmaali, Farzaneh; Mojaverian, Neda; Limberopoulos, Nicholaos I.; Lupu, Anatole

    2014-07-14

    It is shown that the focusing properties of polystyrene microsphere-chain waveguides (MCWs) formed by sufficiently large spheres (D ≥ 20λ, where D is the sphere diameter and λ is the wavelength of light) scale with the sphere diameter as predicted by geometrical optics. However, this scaling behavior does not hold for mesoscale MCWs with D ≤ 10λ resulting in a periodical focusing with gradually reducing beam waists and in extremely small propagation losses. The observed effects are related to properties of nanojet-induced and periodically focused modes in such structures. The results can be used for developing focusing microprobes, laser scalpels, and polarization filters.

  14. Synthesis of sodium caseinate-calcium carbonate microspheres and their mineralization to bone-like apatite

    NASA Astrophysics Data System (ADS)

    Xu, Zhewu; Liang, Guobin; Jin, Lin; Wang, Zhenling; Xing, Chao; Jiange, Qing; Zhang, Zhiguang

    2014-06-01

    Phosphoproteins can induce and stabilize calcium carbonate (CaCO3) vaterite, which has desirable features for high reactivity. The purpose of this study was to synthesize bioactive CaCO3 microspheres for bone regeneration. Sodium caseinate (NaCas)-containing CaCO3 microspheres, with the crystal phase of vaterite, were synthesized by fast precipitation in an aqueous solution of CaCl2, Na2CO3, and 2 mg/mL of NaCas. The uniform microspheres exhibited rougher surfaces and lower negative charges than CaCO3 particles without NaCas addition. Fourier-transform infrared spectroscopy (FT-IR) of the microspheres showed characteristic peaks or bands corresponding to phosphate and hydroxyl groups. Thermogravimetric analysis (TGA) curves exhibited approximately 5% weight loss below 600 °C due to the decomposition of NaCas. Scanning electron microscope (SEM) images showed lath-like hydroxyapatite (HAp) on the surface after soaking in simulated body fluid (SBF) at 37 °C for 5 and 10 days. Energy dispersive X-ray spectrometry (EDS) revealed that the agglomerates were composed of Ca, C, O, P, Na, and Mg elements, and the Ca/P ratios ranged from 1.53 to 1.56. X-ray diffraction (XRD) patterns exhibited peaks characteristic of hydroxyapatite. The results of this study demonstrated that the addition of NaCas induced the formation of vaterite microspheres which possesses an enhanced apatite formation after soaking in SBF at 37 °C for 5 and 10 days. These NaCas-CaCO3 microspheres may be a potential biomaterial for bone regeneration.

  15. Organic aerogel microspheres and fabrication method therefor

    DOEpatents

    Mayer, S.T.; Kong, F.M.; Pekala, R.W.; Kaschmitter, J.L.

    1996-04-16

    Organic aerogel microspheres which can be used in capacitors, batteries, thermal insulation, adsorption/filtration media, and chromatographic packings, having diameters ranging from about 1 micron to about 3 mm. The microspheres can be pyrolyzed to form carbon aerogel microspheres. This method involves stirring the aqueous organic phase in mineral oil at elevated temperature until the dispersed organic phase polymerizes and forms nonsticky gel spheres. The size of the microspheres depends on the collision rate of the liquid droplets and the reaction rate of the monomers from which the aqueous solution is formed. The collision rate is governed by the volume ratio of the aqueous solution to the mineral oil and the shear rate, while the reaction rate is governed by the chemical formulation and the curing temperature.

  16. Organic aerogel microspheres and fabrication method therefor

    DOEpatents

    Mayer, Steven T.; Kong, Fung-Ming; Pekala, Richard W.; Kaschmitter, James L.

    1996-01-01

    Organic aerogel microspheres which can be used in capacitors, batteries, thermal insulation, adsorption/filtration media, and chromatographic packings, having diameters ranging from about 1 micron to about 3 mm. The microspheres can be pyrolyzed to form carbon aerogel microspheres. This method involves stirring the aqueous organic phase in mineral oil at elevated temperature until the dispersed organic phase polymerizes and forms nonsticky gel spheres. The size of the microspheres depends on the collision rate of the liquid droplets and the reaction rate of the monomers from which the aqueous solution is formed. The collision rate is governed by the volume ratio of the aqueous solution to the mineral oil and the shear rate, while the reaction rate is governed by the chemical formulation and the curing temperature.

  17. What Are Gastrointestinal Stromal Tumors?

    MedlinePlus

    ... the digestive system. The gastrointestinal system The gastrointestinal (GI) system (or digestive system) processes food for energy ... bloodstream. This is the longest section of the GI tract, measuring more than 20 feet. The small ...

  18. Holmium-lipiodol-alginate microspheres for fluoroscopy-guided embolotherapy and multimodality imaging.

    PubMed

    Oerlemans, Chris; Seevinck, Peter R; Smits, Maarten L; Hennink, Wim E; Bakker, Chris J G; van den Bosch, Maurice A A J; Nijsen, J Frank W

    2015-03-30

    Embolotherapy is a minimally invasive transcatheter technique aiming at reduction or complete obstruction of the blood flow by infusion of micro-sized particles in order to induce tumor regression. A major drawback of the current commercially available and clinically used microspheres is that they cannot be detected in vivo with medical imaging techniques, impeding intra- and post-procedural feedback. It can be expected that real-time monitoring of microsphere infusion and post-procedural imaging will result in better predictability and higher efficacy of the treatment. In this study, a novel microsphere formulation has been developed that can be visualized with fluoroscopy, X-ray computed tomography (CT) and magnetic resonance imaging (MRI). The microspheres were prepared with the JetCutter technique and consist of alginate (matrix-forming polymer), holmium (cross-linking and MRI contrast agent), lipiodol (radiopaque contrast agent) and Pluronic F-68 (surfactant). The mean size (±SEM) of the hydrated holmium-lipiodol-alginate microspheres (Ho-lip-ams) was 570±12 μm with a holmium content of 0.38±0.01% (w/w). Stability studies showed that the microspheres remained intact during incubation for two weeks in fetal calf serum (FCS) at 37 °C. The inclusion of lipiodol in the microspheres rendered excellent visualization capabilities for fluoroscopy and CT, whereas the holmium ions, which keep the alginate network together, also allow MR imaging. In this study it was shown that single sphere detection was possible by fluoroscopy, CT and MRI. The Ho-lip-ams were visualized in real-time, during infusion in a porcine kidney using fluoroscopy, and post-procedural, the deposition of the microspheres was examined with fluoroscopy, (cone beam rotational) CT and MRI. The different imaging modalities showed similar deposition patterns of the microspheres within the organ. The combination of intra-procedural visualization, multimodality imaging for patient follow-up and the

  19. Genetics Home Reference: gastrointestinal stromal tumor

    MedlinePlus

    ... cells in the gastrointestinal tract and patches of dark skin on various areas of the body. Some ... Cancer Society: Treating Gastrointestinal Stromal Tumor (GIST) Cancer.Net: Gastrointestinal Stromal Tumor--Diagnosis Genetic Testing Registry: Gastrointestinal ...

  20. Hydrogen transport and storage in engineered microspheres

    SciTech Connect

    Rambach, G.; Hendricks, C.

    1996-10-01

    This project is a collaboration between Lawrence Livermore National Laboratory (LLNL) and W.J. Schafer Associates (WJSA). The authors plan to experimentally verify the performance characteristics of engineered glass microspheres that are relevant to the storage and transport of hydrogen for energy applications. They will identify the specific advantages of hydrogen transport by microspheres, analyze the infrastructure implications and requirements, and experimentally measure their performance characteristics in realistic, bulk storage situations.

  1. Method for introduction of gases into microspheres

    DOEpatents

    Hendricks, Charles D.; Koo, Jackson C.; Rosencwaig, Allan

    1981-01-01

    A method for producing small hollow glass spheres filled with a gas by introduction of the gas during formation of the hollow glass spheres. Hollow glass microspheres having a diameter up to about 500.mu. with both thin walls (0.5 to 4.mu.) and thick walls (5 to 20.mu.) that contain various fill gases, such as Ar, Kr, Xe, Br, DT, H.sub.2, D.sub.2, He, N.sub.2, Ne, CO.sub.2, etc. in the interior thereof, can be produced by the diffusion of the fill gas or gases into the microsphere during the formation thereof from a liquid droplet of glass-forming solution. This is accomplished by filling at least a portion of the multiple-zone drop-furnace used in producing hollow microspheres with the gas or gases of interest, and then taking advantage of the high rate of gaseous diffusion of the fill gas through the wall of the gel membrane before it transforms into a glass microsphere as it is processed in the multiple-zone furnace. Almost any gas can be introduced into the inner cavity of a glass microsphere by this method during the formation of the microsphere provided that the gas is diffused into the gel membrane or microsphere prior to its transformation into glass. The process of this invention provides a significant savings of time and related expense of filling glass microspheres with various gases. For example, the time for filling a glass microballoon with 1 atmosphere of DT is reduced from about two hours to a few seconds.

  2. Carbon microsphere-filled Pyrrone foams.

    NASA Technical Reports Server (NTRS)

    Kimmel, B. G.

    1973-01-01

    Syntactic foam formulations were prepared from mixtures of Pyrrone prepolymers and hollow carbon microspheres. Very low curing shrinkages were obtained for high volume loadings of microspheres. The resulting syntactic foams were found to be remarkably stable over a wide range in temperature. A technique was developed for the emplacement of these foam formulations in polyimide-fiberglass, titanium alloy and stainless steel honeycomb without sacrificing low curing shrinkage or thermal stability.

  3. Polyphenols and gastrointestinal diseases

    PubMed Central

    Dryden, Gerald W.; Song, Ming; McClain, Craig

    2014-01-01

    Purpose of review This article will review the role of polyphenols in gastrointestinal diseases. Ingested polyphenols are concentrated in the gastrointestinal tract and are not well absorbed into the rest of the body. Thus, the high luminal concentrations achieved support a potential for therapeutic uses in the gastrointestinal tract. Additionally, there is great interest from the general public in complementary and alternative medicine. Recent findings Dietary polyphenols are a major source of antioxidants consumed by humans. Polyphenols possess not only antioxidant properties but also antiviral, antibacterial, antiinflammatory and anticarcinogenic effects, as well as the ability to modulate certain signaling pathways such as nuclear factor-κB activation. Green tea polyphenols have been shown to have efficacy in various models of inflammatory bowel disease. Silymarin, or milk thistle, is hepatoprotective against many forms of experimental liver injury and is widely used in human liver diseases, such as hepatitis C and alcoholic cirrhosis, with an excellent safety profile (but with unclear efficacy). Summary Substantial in-vitro and animal studies support the beneficial effects of polyphenols in many gastrointestinal diseases. Well designed multicenter trials in humans, such as those called for in the 2005 National Institutes of Health Requests for Applications for Silymarin Centers, will be critical for defining the safety, appropriate dosing and therapeutic efficacy of such agents. PMID:16462174

  4. Gastrointestinal endoscopy in pregnancy

    PubMed Central

    Savas, Nurten

    2014-01-01

    Gastrointestinal endoscopy has a major diagnostic and therapeutic role in most gastrointestinal disorders; however, limited information is available about clinical efficacy and safety in pregnant patients. The major risks of endoscopy during pregnancy include potential harm to the fetus because of hypoxia, premature labor, trauma and teratogenesis. In some cases, endoscopic procedures may be postponed until after delivery. When emergency or urgent indications are present, endoscopic procedures may be considered with some precautions. United States Food and Drug Administration category B drugs may be used in low doses. Endoscopic procedures during pregnancy may include upper gastrointestinal endoscopy, percutaneous endoscopic gastrostomy, sigmoidoscopy, colonoscopy, enteroscopy of the small bowel or video capsule endoscopy, endoscopic retrograde cholangiopancreatography and endoscopic ultrasonography. All gastrointestinal endoscopic procedures in pregnant patients should be performed in hospitals by expert endoscopists and an obstetrician should be informed about all endoscopic procedures. The endoscopy and flexible sigmoidoscopy may be safe for the fetus and pregnant patient, and may be performed during pregnancy when strong indications are present. Colonoscopy for pregnant patients may be considered for strong indications during the second trimester. Although therapeutic endoscopic retrograde cholangiopancreatography may be considered during pregnancy, this procedure should be performed only for strong indications and attempts should be made to minimize radiation exposure. PMID:25386072

  5. Pediatric functional gastrointestinal disorders

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Functional gastrointestinal disorders continue to be a prevalent set of conditions faced by the healthcare team and have a significant emotional and economic impact. In this review, the authors highlight some of the common functional disorders seen in pediatric patients (functional dyspepsia, irrita...

  6. [Gastrointestinal and hepatic diseases].

    PubMed

    Moctezuma-Velázquez, Carlos; Aguirre-Valadez, Jonathan

    2016-09-01

    Diet is considered an important triggering factor for gastrointestinal symptoms whose physiopathology includes not only measurable, inflammatory reactions, but also functional disorders, where no organic effects may be measured or demonstrated. Moreover, the prevalence of the perceived intolerance to certain foods ranges from 20-25% (within the general population) to 50-70% in diseases like irritable bowel syndrome. This intolerance has been observed particularly after the consumption of milk and dairy products, which are frequently considered as causative of gastrointestinal symptoms, thus limiting their ingestion. However, this behavior reduces the dietary sources of calcium and consequently may lead to malnutrition and bone decalcification, amongst other complications. The true dairy intolerance (intestinal lactase deficiency) explains most of the symptoms ensuing their consumption, but the frequency of such alteration on the different gastrointestinal diseases has not been determined. This review focuses on the most frequent gastrointestinal diseases and the existing evidence regarding the alterations and symptoms related to the consumption of milk or dairy products. PMID:27603892

  7. Apollo gastrointestinal analysis

    NASA Technical Reports Server (NTRS)

    Nichols, B. L.; Huang, C. T. L.

    1975-01-01

    Fecal bile acid patterns for the Apollo 17 flight were studied to determine the cause of diarrhea on the mission. The fecal sterol analysis gave no indication of an infectious diarrhea, or specific, or nonspecific etiology occurring during the entire flight. It is assumed that the gastrointestinal problems encountered are the consequences of altered physiology, perhaps secondary to physical or emotional stress of flight.

  8. Gastrointestinal Bleeding in Athletes.

    ERIC Educational Resources Information Center

    Eichner, Edward R.

    1989-01-01

    Describes the scope and importance of gastrointestinal bleeding in runners and other athletes, discussing causes, sites, and implications of exercise-related bleeding. Practical tips to mitigate the problem, potentially more troublesome in women because of lower iron stores, are presented (e.g., gradual conditioning and avoidance of prerace…

  9. Animal models of gastrointestinal inflammation and cancer.

    PubMed

    Lu, L; Chan, Ruby L Y; Luo, X M; Wu, William K K; Shin, Vivian Y; Cho, C H

    2014-07-11

    Inflammation and cancer are the two major disorders in the gastrointestinal tract. They are causally related in their pathogenesis. It is important to study animal models' causal relationship and, in particular, to discover new therapeutic agents for such diseases. There are several criteria for these models in order to make them useful in better understanding the etiology and treatment of the said diseases in humans. In this regard, animal models should be similar as possible to human diseases and also be easy to produce and reproducible and also economic to allow a continuous replication in different laboratories. In this review, we summarize the various animal models for inflammatory and cancerous disorders in the upper and lower gastrointestinal tract. Experimental approaches are as simple as by giving a single oral dose of alcohol or other noxious agents or by injections of multiple dosages of ulcer inducing agents or by parenteral administration or in drinking water of carcinogens or by modifying the genetic makeups of animals to produce relatively long-term pathological changes in particular organs. With these methods they could induce consistent inflammatory responses or tumorigenesis in the gastrointestinal mucosa. These animal models are widely used in laboratories in understanding the pathogenesis as well as the mechanisms of action for therapeutic agents in the treatment of gastrointestinal inflammation and cancer. PMID:24825611

  10. Demonstration of Microsphere Insulation in Cryogenic Vessels

    NASA Astrophysics Data System (ADS)

    Baumgartner, R. G.; Myers, E. A.; Fesmire, J. E.; Morris, D. L.; Sokalski, E. R.

    2006-04-01

    While microspheres have been recognized as a legitimate insulation material for decades, actual use in full-scale cryogenic storage tanks has not been demonstrated until now. The performance and life-cycle-cost advantages previously predicted have now been proven. Most bulk cryogenic storage tanks are insulated with either multilayer insulation (MLI) or perlite. Microsphere insulation, consisting of hollow glass bubbles, combines in a single material the desirable properties that other insulations only have individually. The material has high crush strength, low density, is noncombustible, and performs well in soft vacuum. These properties were proven during recent field testing of two 22,700-L (6,000-gallon) liquid nitrogen tanks, one insulated with microsphere insulation and the other with perlite. Normal evaporation rates (NER) for both tanks were monitored with precision test equipment and insulation levels within the tanks were observed through view ports as an indication of insulation compaction. Specific industrial applications were evaluated based on the test results and beneficial properties of microsphere insulation. Over-the-road trailers previously insulated with perlite will benefit not only from the reduced heat leak, but also the reduced mass of microsphere insulation. Economic assessments for microsphere-insulated cryogenic vessels including life-cycle cost are also presented.

  11. Haemochromatosis and gastrointestinal cancer.

    PubMed

    Lagergren, Katarina; Wahlin, Karl; Mattsson, Fredrik; Alderson, Derek; Lagergren, Jesper

    2016-10-15

    Iron overload in patients with haemochromatosis is a strong risk factor for liver cancer, but its influence on other gastrointestinal cancer risk is unclear. The aim was to assess the relative risk of luminal gastrointestinal cancer among patients diagnosed with haemochromatosis. This population-based, nationwide Swedish cohort study included patients with haemochromatosis in Sweden in 1965-2013. The incidence of gastrointestinal cancers was assessed through the Swedish Cancer Registry. The measure of relative risk was the standardised incidence ratio (SIR) with 95% confidence interval (CI), that is, the ratio of the observed number of gastrointestinal cancers in the haemochromatosis cohort divided by the expected number of such cancers, calculated from the entire corresponding background population of Sweden. Among 6,849 patients in the haemochromatosis cohort with up to 48 years of follow-up, the SIRs were 3-fold increased for oesophageal squamous cell carcinoma (SIR = 3.2, 95% CI 1.3-6.6; n = 7) and 40% increased for colon adenocarcinoma (SIR = 1.4, 95% CI 1.1-1.9; n = 54). No associations were found between haemochromatosis and the risk of adenocarcinoma of the oesophagus (SIR = 0.5, 95% CI 0.0-2.5; n = 1), stomach (SIR = 0.7, 95% CI 0.3-1.4; n = 8), small bowel (SIR = 1.2, 95% CI 0.0-6.7; n = 1) or rectum (SIR = 1.0, 95% CI 0.6-1.6; n = 21). These findings indicate that haemochromatosis increases the risk of oesophageal squamous cell carcinoma and colon adenocarcinoma, but might not influence the risk of other types of luminal gastrointestinal cancer. These findings should encourage further research examining the role of iron overload in cancer aetiology. PMID:27300578

  12. Controlled synthesis of three-dimensional hierarchical Bi{sub 2}WO{sub 6} microspheres with optimum photocatalytic activity

    SciTech Connect

    Wang, Hong; Song, Jimei; Zhang, Hui; Gao, Fei; Zhao, Shaojuan; Hu, Haiqin

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer The synthesized method is very simple. It can be widely used in the production. Black-Right-Pointing-Pointer The morphology is novel and the property is fine. Black-Right-Pointing-Pointer The formation of 3D hierarchical microsphere can be induced by changing the concentration of KNO{sub 3}. -- Abstract: Three-dimensional (3D) hierarchical Bi{sub 2}WO{sub 6} microsphere and octahedral Bi{sub 2}WO{sub 6} have been synthesized by a facile hydrothermal method using KNO{sub 3} solution and distilled water as solvent, respectively. The obtained products were characterized by X-ray diffraction, scanning electron microscopy, N{sub 2} adsorption/desorption, and UV-vis diffuse reflectance spectroscopy in detail. The concentration of KNO{sub 3} played a key role in the formation of 3D hierarchical Bi{sub 2}WO{sub 6} microspheres. A possible formation mechanism of Bi{sub 2}WO{sub 6} microsphere was proposed. The photocatalytic activity of the as-synthesized products was evaluated by monitoring the degradation of MB solution under sunlight irradiation. It was found that the photocatalytic activity of the 3D hierarchical Bi{sub 2}WO{sub 6} microsphere was superior to the octahedral Bi{sub 2}WO{sub 6}, which was attributed to the larger surface area and special hierarchical structure of Bi{sub 2}WO{sub 6} microsphere.

  13. Simultaneous nano- and micro-scale control of nanofibrous microspheres self-assembled from star-shaped polymers

    PubMed Central

    Zhang, Zhanpeng; Marson, Ryan L.; Ge, Zhishen; Glotzer, Sharon C.; Ma, Peter X.

    2015-01-01

    The mechanism underlying the multi-scale self-assembly of star-shaped polymers into non-hollow, hollow, and spongy nanofibrous microspheres is reported. Star-shaped poly(L-lactic acid) polymers with varying arm-numbers and arm-lengths are synthesized, dissolved in tetrahydrofuran, emulsified in glycerol, and thermally-induced to phase separate, resulting in microspheres that are either smooth or fibrous on the nano-scale, and either non-hollow, hollow, or spongy on the micro-scale. Molecular architecture and the hydroxyl density are shown to control assembly and morphology at both nano- and micro-scales. Nanofibers form only when the arm length is sufficiently long, while an increase in hydroxyl density causes the microspheres to change from non-hollow to hollow to spongy. We demonstrate via both experiments of capping or doubling the hydroxyl end groups and dissipative particle dynamics simulations that the affinity of hydroxyl to glycerol is critical to stabilizing the micro-scale structure. A “phase diagram” was constructed for the six types of microspheres in relation to the molecular structures of the star-shaped polymers. The proposed mechanism explains how star-shaped polymers self-assemble into various microspheres, and guides us to simultaneously control both nano- and micro-features of the microspheres. PMID:26009995

  14. Pulmonary-impedance power spectral analysis: A facile means of detecting radiation-induced gastrointestinal distress and performance decrement in man

    NASA Technical Reports Server (NTRS)

    Rick, R. C.; Lushbaugh, C. C.; Mcdow, E.; Frome, E.

    1972-01-01

    Changes in respiratory variance revealed by power spectral analysis of the pulmonary impedance pneumogram can be used to detect and measure stresses directly or indirectly affecting human respiratory function. When gastrointestinal distress occurred during a series of 5 total-body exposures of 30 R at a rate of 1.5 R/min, it was accompanied by typical shifts in pulmonary impedance power spectra. These changes did not occur after protracted exposure of 250 R (30 R daily) at 1.5 R/hr that failed to cause radiation sickness. This system for quantitating respiratory effort can also be used to detect alterations in one's ability to perform under controlled exercise conditions.

  15. Enhanced Gastrointestinal Expression of Cytosolic Malic Enzyme (ME1) Induces Intestinal and Liver Lipogenic Gene Expression and Intestinal Cell Proliferation in Mice

    PubMed Central

    Al-Dwairi, Ahmed; Brown, Adam R.; Pabona, John Mark P.; Van, Trang H.; Hamdan, Hamdan; Mercado, Charles P.; Quick, Charles M.; Wight, Patricia A.; Simmen, Rosalia C. M.; Simmen, Frank A.

    2014-01-01

    The small intestine participates in lipid digestion, metabolism and transport. Cytosolic malic enzyme 1 (ME1) is an enzyme that generates NADPH used in fatty acid and cholesterol biosynthesis. Previous work has correlated liver and adipose ME1 expression with susceptibility to obesity and diabetes; however, the contributions of intestine-expressed ME1 to these conditions are unknown. We generated transgenic (Tg) mice expressing rat ME1 in the gastrointestinal epithelium under the control of the murine villin1 promoter/enhancer. Levels of intestinal ME1 protein (endogenous plus transgene) were greater in Tg than wildtype (WT) littermates. Effects of elevated intestinal ME1 on body weight, circulating insulin, select adipocytokines, blood glucose, and metabolism-related genes were examined. Male Tg mice fed a high-fat (HF) diet gained significantly more body weight than WT male littermates and had heavier livers. ME1-Tg mice had deeper intestinal and colon crypts, a greater intestinal 5-bromodeoxyuridine labeling index, and increased expression of intestinal lipogenic (Fasn, Srebf1) and cholesterol biosynthetic (Hmgcsr, Hmgcs1), genes. The livers from HF diet-fed Tg mice also exhibited an induction of cholesterol and lipogenic pathway genes and altered measures (Irs1, Irs2, Prkce) of insulin sensitivity. Results indicate that gastrointestinal ME1 via its influence on intestinal epithelial proliferation, and lipogenic and cholesterologenic genes may concomitantly impact signaling in liver to modify this tissue’s metabolic state. Our work highlights a new mouse model to address the role of intestine-expressed ME1 in whole body metabolism, hepatomegaly, and crypt cell proliferation. Intestinal ME1 may thus constitute a therapeutic target to reduce obesity-associated pathologies. PMID:25402228

  16. Gastrointestinal Degradation of Fumonisin B₁ by Carboxylesterase FumD Prevents Fumonisin Induced Alteration of Sphingolipid Metabolism in Turkey and Swine.

    PubMed

    Masching, Sabine; Naehrer, Karin; Schwartz-Zimmermann, Heidi-Elisabeth; Sărăndan, Mihai; Schaumberger, Simone; Dohnal, Ilse; Nagl, Veronika; Schatzmayr, Dian

    2016-03-01

    The mycotoxin fumonisin B₁ (FB₁) is a frequent contaminant of feed and causes various adverse health effects in domestic animals. Hence, effective strategies are needed to prevent the impact of fumonisins on livestock productivity. Here we evaluated the capability of the fumonisin carboxylesterase FumD to degrade FB₁ to its less toxic metabolite hydrolyzed FB₁ (HFB₁) in the gastrointestinal tract of turkeys and pigs. First, an ex vivo pig model was used to examine the activity of FumD under digestive conditions. Within 2 h of incubation with FumD, FB₁ was completely degraded to HFB₁ in the duodenum and jejunum, respectively. To test the efficacy of the commercial application of FumD (FUMzyme) in vivo, female turkeys (n = 5) received either basal feed (CON), fumonisin-contaminated feed (15 mg/kg FB₁+FB₂; FB) or fumonisin-contaminated feed supplemented with FUMzyme (15 U/kg; FB+FUMzyme) for 14 days ad libitum. Addition of FUMzyme resulted in significantly decreased levels of FB₁ in excreta, whereas HFB₁ concentrations were significantly increased. Compared to the FB group (0.24 ± 0.02), the mean serum sphinganine-to-sphingosine (Sa/So) ratio was significantly reduced in the FB+FUMzyme group (0.19 ± 0.02), thus resembling values of the CON group (0.16 ± 0.02). Similarly, exposure of piglets (n = 10) to 2 mg/kg FB₁+FB₂ for 42 days caused significantly elevated serum Sa/So ratios (0.39 ± 0.15) compared to the CON group (0.14 ± 0.01). Supplementation with FUMzyme (60 U/kg) resulted in gastrointestinal degradation of FB₁ and unaffected Sa/So ratios (0.16 ± 0.02). Thus, the carboxylesterase FumD represents an effective strategy to detoxify FB₁ in the digestive tract of turkeys and pigs. PMID:27007395

  17. Gastrointestinal Malignancy and the Microbiome

    PubMed Central

    Abreu, Maria T.; Peek, Richard M.

    2014-01-01

    Microbial species participate in the genesis of a substantial number of malignancies—in conservative estimates, at least 15% of all cancer cases are attributable to infectious agents. Little is known about the contribution of the gastrointestinal (GI) microbiome to the development of malignancies. Resident microbes can promote carcinogenesis by inducing inflammation, increasing cell proliferation, altering stem cell dynamics, and producing metabolites such as butyrate, which affect DNA integrity and immune regulation. Studies in humans and rodent models of cancer have identified effector species and relationships among members of the microbial community in the stomach and colon that increase the risk for malignancy. Strategies to manipulate the microbiome, or the immune response to such bacteria, could be developed to prevent or treat certain GI cancers. PMID:24406471

  18. Studies on the preparation, characterization and pharmacological evaluation of tolterodine PLGA microspheres.

    PubMed

    Sun, Fengying; Sui, Cheng; Teng, Lesheng; Liu, Ximing; Teng, Lirong; Meng, Qingfan; Li, Youxin

    2010-09-15

    In this study, poly(d,l-lactide-co-glycolide) (PLGA) microspheres of tolterodine depot formulation were prepared using oil in water (o/w) method to investigate their potential pharmacokinetic and pharmacodynamic advantages over tolterodine l-tartrate tablets. Morphological studies of the microspheres showed a spherical shape and smooth surface with mean size of 50.69-83.01 microm, and the encapsulation efficiency was improved from 62.55 to 79.10% when the polymer concentration increased from 180 to 230 mg/ml. The addition of stearic or palmitic acids could significantly raise the drug entrapment efficiency but only slightly affected the in vitro release. A low initial burst followed by a proximately constant release of tolterodine was noticed in the in vitro release profiles. The in vivo study was carried out by intramuscular (i.m.) administration of tolterodine-loaded microspheres on beagle dogs, and a sustained release of drug from the PLGA microspheres was achieved until the 18th day with a low initial burst. Since the absence of hepatic first pass metabolism, only a single active compound-tolterodine was detected in the plasma. This avoided the coexistence of two active compounds in plasma in the case of oral administration of tolterodine, which may lead to a difficulty in dose control due to the different metabolic capacity of patients. In the pharmacodynamic study, the influence of tolterodine PLGA microspheres on the inhibition of carbachol-induced rat urinary bladder contraction was more significant than that of tolterodine l-tartrate tablets. There were invisible changes in rat bladder slices between tolterodine-loaded PLGA microspheres group and tolterodine l-tartrate tablets group. These results indicate that the continuous inhibition of muscarinic receptor may offer an alternative therapy of urge incontinence. PMID:20600717

  19. [Microbiota and gastrointestinal diseases].

    PubMed

    Polanco Allué, I

    2015-12-01

    The bacterial colonisation is established immediately after birth, through direct contact with maternal microbiota, and may be influenced during lactation. There is emerging evidence indicating that quantitative and qualitative changes on gut microbiota contribute to alterations in the mucosal activation of the immune system, leading to intra- or extra-intestinal diseases. A balance between pathogenic and beneficial microbiota throughout childhood and adolescence is important to gastrointestinal health, including protection against pathogens, inhibition of pathogens, nutrient processing (synthesis of vitamin K), stimulation of angiogenesis, and regulation of host fat storage. Probiotics can promote an intentional modulation of intestinal microbiota favouring the health of the host. A review is presented on the modulation of intestinal microbiota on prevention, and adjuvant treatment of some paediatric gastrointestinal diseases. PMID:26534880

  20. Acute upper gastrointestinal bleeding.

    PubMed

    Kurien, Matthew; Lobo, Alan J

    2015-10-01

    Acute upper gastrointestinal bleeding (AUGIB) is a frequently encountered medical emergency with an incidence of 84-160/100000 and associated with mortality of approximately 10%. Guidelines from the National Institute for Care and Care Excellence outline key features in the management of AUGIB. Patients require prompt resuscitation and risk assessment using validated tools. Upper gastrointestinal endoscopy provides accurate diagnosis, aids in estimating prognosis and allows therapeutic intervention. Endoscopy should be undertaken immediately after resuscitation in unstable patients and within 24 hours in all other patients. Interventional radiology may be required for bleeding unresponsive to endoscopic intervention. Drug therapy depends on the cause of bleeding. Intravenous proton pump inhibitors should be used in patients with high-risk ulcers. Terlipressin and broad-spectrum antibiotics should be used following variceal haemorrhage. Hospitals admitting patients with AUGIB need to provide well organised services and ensure access to relevant services for all patients, and particularly to out of hours endoscopy. PMID:26430191

  1. [Zinc and gastrointestinal disorders].

    PubMed

    Higashimura, Yasuki; Takagi, Tomohisa; Naito, Yuji

    2016-07-01

    Zinc, an essential trace element, affects immune responses, skin metabolism, hormone composition, and some sensory function, so that the deficiency presents various symptoms such as immunodeficiency and taste obstacle. Further, the zinc deficiency also considers as a risk of various diseases. Recent reports demonstrated that -20% of the Japanese population was marginally zinc deficiency, and over 25% of the global population is at high risk of zinc deficiency. In gastrointestinal disorders, zinc plays an important role in the healing of mucosal and epithelial damage. In fact, polaprezinc, a chelate compound of zinc and L-carnosine, has been used for the treatment of gastric ulcer and gastritis. We describe here the therapeutic effect of zinc on gastrointestinal disorders. PMID:27455800

  2. Gastrointestinal stromal tumour.

    PubMed

    Joensuu, Heikki; Hohenberger, Peter; Corless, Christopher L

    2013-09-14

    Gastrointestinal stromal tumours (GISTs) are mesenchymal neoplasms that arise in the gastrointestinal tract, usually in the stomach or the small intestine and rarely elsewhere in the abdomen. They can occur at any age, the median age being 60-65 years, and typically cause bleeding, anaemia, and pain. GISTs have variable malignant potential, ranging from small lesions with a benign behaviour to fatal sarcomas. Most tumours stain positively for the mast/stem cell growth factor receptor KIT and anoctamin 1 and harbour a kinase-activating mutation in either KIT or PDGFRA. Tumours without such mutations could have alterations in genes of the succinate dehydrogenase complex or in BRAF, or rarely RAS family genes. About 60% of patients are cured by surgery. Adjuvant treatment with imatinib is recommended for patients with a substantial risk of recurrence, if the tumour has an imatinib-sensitive mutation. Tyrosine kinase inhibitors substantially improve survival in advanced disease, but secondary drug resistance is common. PMID:23623056

  3. Patterning Poly(dimethylsiloxane) Microspheres via Combination of Oxygen Plasma Exposure and Solvent Treatment.

    PubMed

    Li, Qiaoyuan; Han, Xue; Hou, Jing; Yin, Jian; Jiang, Shichun; Lu, Conghua

    2015-10-22

    Here a simple low-cost yet robust route has been developed to prepare poly(dimethylsiloxane) (PDMS) microspheres with various surface wrinkle patterns. First, the aqueous-phase-synthesized PDMS microspheres are exposed to oxygen plasma (OP), yielding the oxidized SiOx layer and the corresponding stiff shell/compliant core system. The subsequent solvent swelling and solvent evaporation induce the spontaneous formation of a series of curvature and overstress-sensitive spherical wrinkles such as dimples, short rodlike depressions, and herringbone and labyrinth patterns. The effects of the experimental parameters, including the radius and Young's modulus of the microspheres, the OP exposure duration, and the nature of the solvents, on these tunable spherical wrinkles have been systematically studied. The experimental results reveal that a power-law dependence of the wrinkling wavelength on the microsphere radius exists. Furthermore, the induced wrinkling patterns are inherently characteristic of a memory effect and good reversibility. Meanwhile, the corresponding phase diagram of the wrinkle morphologies on the spherical surfaces vs the normalized radius of curvature and the excess swelling degree has been demonstrated. It is envisioned that the introduced strategy in principle could be applied to other curved surfaces for expeditious generation of well-defined wrinkle morphologies, which not only enables the fabrication of solids with multifunctional surface properties, but also provides important implications for the morphogenesis in soft materials and tissues. PMID:26435184

  4. Pediatric gastrointestinal imaging

    SciTech Connect

    Stringer, D.D. )

    1989-01-01

    This book is on imaging of the gastrointestinal tract in children. Discussions of each condition include all imaging modalities plain film, computed tomography, sonography, magnetic resonance imaging and interventional radiology. It highlights key points, outstanding information on the techniques of examination of the child and infant, material on embryogenesis, and an in-depth bibliography. It also covers how and why to perform such interventional techniques as foreign body removal, drainage of abscesses or fluid collections, intestinal tube placement, and much more.

  5. NSAIDS and gastrointestinal cancer.

    PubMed

    Piazuelo, Elena; Lanas, Angel

    2015-07-01

    A large body of evidence from epidemiological and preclinical studies have shown that nonsteroideal anti-inflammatory drugs (NSAIDs) have a chemopreventive effect on gastrointestinal cancers and, more specifically, in colorectal cancer. This review highlights recent advances in our understanding of the role of NSAIDs in colorectal cancer prevention and adjuvant treatment. Moreover, we have focused on randomized controlled studies assessing their efficacy to prevent adenoma recurrence and reduction of colorectal cancer incidence and mortality but also their gastrointestinal and cardiovascular side effects. Among NSAIDs, almost the unique agent with potential use as chemopreventive agent is aspirin at low dose since it has both no cardiovascular and low gastrointestinal risk. Furthermore, since aspirin has shown efficacy in secondary prevention of cardiovascular diseases, this drug carries a particular attractive intervention for selected populations. Nevertheless, before it can be prescribed, further studies are necessary to define some important questions, specially the most appropriate dose and time of aspirin use and the population who may benefit from it. PMID:26093284

  6. Network Meta-Analysis Comparing Relatively Selective COX-2 Inhibitors Versus Coxibs for the Prevention of NSAID-Induced Gastrointestinal Injury

    PubMed Central

    Yang, Man; Wang, Hong-Tao; Zhao, Miao; Meng, Wen-Bo; Ou, Jin-Qing; He, Jun-Hui; Zou, Bing; Lei, Ping-Guang

    2015-01-01

    Abstract Currently 2 difference classes of cyclooxygenase (COX)-2 inhibitors, coxibs and relatively selective COX-2 inhibitors, are available for patients requiring nonsteroidal anti-inflammatory drug (NSAID) therapy; their gastroprotective effect is hardly directly compared. The aim of this study was to compare the gastroprotective effect of relatively selective COX-2 inhibitors with coxibs. MEDLINE, EMBASE, and the Cochrane Library (from their inception to March 2015) were searched for potential eligible studies. We included randomized controlled trials comparing coxibs (celecoxib, etoricoxib, parecoxib, and lumiracoxib), relatively selective COX-2 inhibitors (nabumetone, meloxicam, and etodolac), and nonselective NSAIDs with a study duration ≥4 weeks. Comparative effectiveness and safety data were pooled by Bayesian network meta-analysis. The primary outcomes were ulcer complications and symptomatic ulcer. Summary effect-size was calculated as risk ratio (RR), together with the 95% confidence interval (CI). This study included 36 trials with a total of 112,351 participants. Network meta-analyses indicated no significant difference between relatively selective COX-2 inhibitors and coxibs regarding ulcer complications (RR, 1.38; 95% CI, 0.47–3.27), symptomatic ulcer (RR, 1.02; 95% CI, 0.09–3.92), and endoscopic ulcer (RR, 1.18; 95% CI, 0.37–2.96). Network meta-analyses adjusting potential influential factors (age, sex, previous ulcer disease, and follow-up time), and sensitivity analyses did not reveal any major change to the main results. Network meta-analyses suggested that relatively selective COX-2 inhibitors and coxibs were associated with comparable incidences of total adverse events (AEs) (RR, 1.09; 95% CI, 0.93–1.31), gastrointestinal AEs (RR, 1.04; 95% CI, 0.87–1.25), total withdrawals (RR, 1.00; 95% CI, 0.74–1.33), and gastrointestinal AE-related withdrawals (RR, 1.02; 95% CI, 0.57–1.74). Relatively selective COX-2 inhibitors appear to be

  7. Network Meta-Analysis Comparing Relatively Selective COX-2 Inhibitors Versus Coxibs for the Prevention of NSAID-Induced Gastrointestinal Injury.

    PubMed

    Yang, Man; Wang, Hong-Tao; Zhao, Miao; Meng, Wen-Bo; Ou, Jin-Qing; He, Jun-Hui; Zou, Bing; Lei, Ping-Guang

    2015-10-01

    Currently 2 difference classes of cyclooxygenase (COX)-2 inhibitors, coxibs and relatively selective COX-2 inhibitors, are available for patients requiring nonsteroidal anti-inflammatory drug (NSAID) therapy; their gastroprotective effect is hardly directly compared. The aim of this study was to compare the gastroprotective effect of relatively selective COX-2 inhibitors with coxibs. MEDLINE, EMBASE, and the Cochrane Library (from their inception to March 2015) were searched for potential eligible studies. We included randomized controlled trials comparing coxibs (celecoxib, etoricoxib, parecoxib, and lumiracoxib), relatively selective COX-2 inhibitors (nabumetone, meloxicam, and etodolac), and nonselective NSAIDs with a study duration ≥ 4 weeks. Comparative effectiveness and safety data were pooled by Bayesian network meta-analysis. The primary outcomes were ulcer complications and symptomatic ulcer. Summary effect-size was calculated as risk ratio (RR), together with the 95% confidence interval (CI). This study included 36 trials with a total of 112,351 participants. Network meta-analyses indicated no significant difference between relatively selective COX-2 inhibitors and coxibs regarding ulcer complications (RR, 1.38; 95% CI, 0.47-3.27), symptomatic ulcer (RR, 1.02; 95% CI, 0.09-3.92), and endoscopic ulcer (RR, 1.18; 95% CI, 0.37-2.96). Network meta-analyses adjusting potential influential factors (age, sex, previous ulcer disease, and follow-up time), and sensitivity analyses did not reveal any major change to the main results. Network meta-analyses suggested that relatively selective COX-2 inhibitors and coxibs were associated with comparable incidences of total adverse events (AEs) (RR, 1.09; 95% CI, 0.93-1.31), gastrointestinal AEs (RR, 1.04; 95% CI, 0.87-1.25), total withdrawals (RR, 1.00; 95% CI, 0.74-1.33), and gastrointestinal AE-related withdrawals (RR, 1.02; 95% CI, 0.57-1.74). Relatively selective COX-2 inhibitors appear to be associated with

  8. Gastrointestinal Degradation of Fumonisin B1 by Carboxylesterase FumD Prevents Fumonisin Induced Alteration of Sphingolipid Metabolism in Turkey and Swine

    PubMed Central

    Masching, Sabine; Naehrer, Karin; Schwartz-Zimmermann, Heidi-Elisabeth; Sărăndan, Mihai; Schaumberger, Simone; Dohnal, Ilse; Nagl, Veronika; Schatzmayr, Dian

    2016-01-01

    The mycotoxin fumonisin B1 (FB1) is a frequent contaminant of feed and causes various adverse health effects in domestic animals. Hence, effective strategies are needed to prevent the impact of fumonisins on livestock productivity. Here we evaluated the capability of the fumonisin carboxylesterase FumD to degrade FB1 to its less toxic metabolite hydrolyzed FB1 (HFB1) in the gastrointestinal tract of turkeys and pigs. First, an ex vivo pig model was used to examine the activity of FumD under digestive conditions. Within 2 h of incubation with FumD, FB1 was completely degraded to HFB1 in the duodenum and jejunum, respectively. To test the efficacy of the commercial application of FumD (FUMzyme) in vivo, female turkeys (n = 5) received either basal feed (CON), fumonisin-contaminated feed (15 mg/kg FB1+FB2; FB) or fumonisin-contaminated feed supplemented with FUMzyme (15 U/kg; FB+FUMzyme) for 14 days ad libitum. Addition of FUMzyme resulted in significantly decreased levels of FB1 in excreta, whereas HFB1 concentrations were significantly increased. Compared to the FB group (0.24 ± 0.02), the mean serum sphinganine-to-sphingosine (Sa/So) ratio was significantly reduced in the FB+FUMzyme group (0.19 ± 0.02), thus resembling values of the CON group (0.16 ± 0.02). Similarly, exposure of piglets (n = 10) to 2 mg/kg FB1+FB2 for 42 days caused significantly elevated serum Sa/So ratios (0.39 ± 0.15) compared to the CON group (0.14 ± 0.01). Supplementation with FUMzyme (60 U/kg) resulted in gastrointestinal degradation of FB1 and unaffected Sa/So ratios (0.16 ± 0.02). Thus, the carboxylesterase FumD represents an effective strategy to detoxify FB1 in the digestive tract of turkeys and pigs. PMID:27007395

  9. Food-associated Stimuli Enhance Barrier Properties of Gastrointestinal Mucus

    PubMed Central

    Yildiz, Hasan M.; Speciner, Lauren; Ozdemir, Cafer; Cohen, David E.; Carrier, Rebecca L.

    2015-01-01

    Orally delivered drugs and nutrients must diffuse through mucus to enter the circulatory system, but the barrier properties of mucus and their modulation by physiological factors are generally poorly characterized. The main objective of this study was to examine the impact of physicochemical changes occurring upon food ingestion on gastrointestinal (GI) mucus barrier properties. Lipids representative of postprandial intestinal contents enhanced mucus barriers, as indicated by a 10 – 142-fold reduction in the transport rate of 200 nm microspheres through mucus, depending on surface chemistry. Physiologically relevant increases in [Ca2+] resulted in a 2 - 4-fold reduction of transport rates, likely due to enhanced cross-linking of the mucus gel network. Reduction of pH from 6.5 to 3.5 also affected mucus viscoelasticity, reducing particle transport rates approximately 5 – 10-fold. Macroscopic visual observation and micro-scale lectin staining revealed mucus gel structural changes, including clumping into regions into which particles did not penetrate. Histological examination indicated food ingestion can prevent microsphere contact with and endocytosis by intestinal epithelium. Taken together, these results demonstrate that GI mucus barriers are significantly altered by stimuli associated with eating and potentially dosing of lipid-based delivery systems; these stimuli represent broadly relevant variables to consider upon designing oral therapies. PMID:25907034

  10. Food-associated stimuli enhance barrier properties of gastrointestinal mucus.

    PubMed

    Yildiz, Hasan M; Speciner, Lauren; Ozdemir, Cafer; Cohen, David E; Carrier, Rebecca L

    2015-06-01

    Orally delivered drugs and nutrients must diffuse through mucus to enter the circulatory system, but the barrier properties of mucus and their modulation by physiological factors are generally poorly characterized. The main objective of this study was to examine the impact of physicochemical changes occurring upon food ingestion on gastrointestinal (GI) mucus barrier properties. Lipids representative of postprandial intestinal contents enhanced mucus barriers, as indicated by a 10-142-fold reduction in the transport rate of 200 nm microspheres through mucus, depending on surface chemistry. Physiologically relevant increases in [Ca(2+)] resulted in a 2-4-fold reduction of transport rates, likely due to enhanced cross-linking of the mucus gel network. Reduction of pH from 6.5 to 3.5 also affected mucus viscoelasticity, reducing particle transport rates approximately 5-10-fold. Macroscopic visual observation and micro-scale lectin staining revealed mucus gel structural changes, including clumping into regions into which particles did not penetrate. Histological examination indicated food ingestion can prevent microsphere contact with and endocytosis by intestinal epithelium. Taken together, these results demonstrate that GI mucus barriers are significantly altered by stimuli associated with eating and potentially dosing of lipid-based delivery systems; these stimuli represent broadly relevant variables to consider upon designing oral therapies. PMID:25907034

  11. Influence of simulated gastrointestinal conditions on particle-induced cytotoxicity and interleukin-8 regulation in differentiated and undifferentiated Caco-2 cells.

    PubMed

    Gerloff, Kirsten; Pereira, Dora I A; Faria, Nuno; Boots, Agnes W; Kolling, Julia; Förster, Irmgard; Albrecht, Catrin; Powell, Jonathan J; Schins, Roel P F

    2013-06-01

    Novel aspects of engineered nanoparticles offer many advantages for optimising food products and packaging. However, their potential hazards in the gastrointestinal tract require further investigation. We evaluated the toxic and inflammatory potential of two types of particles that might become increasingly relevant to the food industry, namely SiO₂ and ZnO. The materials were characterised for their morphology, oxidant generation and hydrodynamic behaviour. Cytotoxicity and interleukin-8 mRNA and protein expression were evaluated in human intestinal Caco-2 cells. Particle pretreatment under simulated gastric and intestinal pH conditions resulted in reduced acellular ROS formation but did not influence cytotoxicity (WST-1 assay) or IL-8 expression. However, the differentiation status of the cells markedly determined the cytotoxic potency of the particles. Further research is needed to determine the in vivo relevance of our current observations regarding the role of particle aggregation and the stage of intestinal epithelial cell differentiation in determining the hazards of ingested particles. PMID:22394261

  12. A facile synthesis of luminescent YVO4:Eu3+ hollow microspheres in virtue of template function of the SDS-PEG soft clusters

    NASA Astrophysics Data System (ADS)

    Wang, Juan; Yan, Yinglin; Hojamberdiev, Mirabbos; Ruan, Xiaoguang; Cai, Anjiang; Xu, Yunhua

    2012-08-01

    Hollow europium-doped yttrium orthovanadate (YVO4:Eu3+) microspheres were fabricated via a sodium dodecyl sulfate (SDS)-polyethylene glycol (PEG)-assisted hydrothermal technique. The as-synthesized hollow YVO4:Eu3+ microspheres were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence spectroscopy (PL). The obtained results showed that the morphology and size of the hollow microspheres have a strong dependence on the hydrothermal reaction time of the YVO4:Eu3+ powders. It is believed that the SDS-PEG clusters perform a function of dual soft-template that results in a unique template-induced secondary assembly in the one-pot synthesis of hollow YVO4:Eu3+ microspheres. The photoluminescence measurement revealed that the YVO4:Eu3+ powders with a spherical hollow shape have better red luminescence compared to the YVO4:Eu3+ solid microspheres. As a result, the controlled synthesis of hollow YVO4:Eu3+ microspheres not only has a great theoretical significance in studying the three-dimensional control and selective synthesis of inorganic materials but also benefits the potential applications based on hollow YVO4:Eu3+ microspheres owing to reducing the usage of expensive rare-earth elements.

  13. Characterization and evaluation of triamcinolone, raloxifene, and their dual-loaded microspheres as prospective local treatment system in rheumatic rat joints.

    PubMed

    Ocal, Yigit; Kurum, Baris; Karahan, Siyami; Tezcaner, Aysen; Ozen, Seza; Keskin, Dilek

    2014-08-01

    In this study, injectable microspheres were developed for the local treatment of joint degeneration in rheumatoid arthritis (RA). Microspheres loaded with triamcinolone (TA), a corticosteroid drug, and/or raloxifene (Ral), a cartilage regenerative drug, were prepared with a biodegradable and biocompatible polymer, polycaprolactone (PCL). Microspheres were optimized for particle size, structural properties, drug release, and loading properties. In vitro release of Ral was very slow because of the low solubility of the drug and hydrophobic nature of PCL. However, when coloaded with TA, both drugs were released at higher amounts compared with their single forms. Smallest particle sizes were obtained in dual drug-loaded microspheres. In vitro cytotoxicity tests showed biocompatibility of microspheres. In vivo bioefficacy of these microspheres was also examined in adjuvant-induced arthritis model in rats. In vivo histological studies of control groups showed development of RA with high median lesion score (5.0). Compared with control and intra-articular free drug injections, microsphere treatment groups showed lower lesion scores and better healing outcomes in histological evaluations. Results suggest that a controlled delivery system of TA and RAL by a single injection in inflamed joints holds promise for healing and suppressing inflammation. PMID:24939720

  14. Carboxymethyl starch mucoadhesive microspheres as gastroretentive dosage form.

    PubMed

    Lemieux, Marc; Gosselin, Patrick; Mateescu, Mircea Alexandru

    2015-12-30

    Carboxymethyl starch microspheres (CMS-MS) were produced from carboxymethyl starch powder (CMS-P) with a degree of substitution (DS) from 0.1 to 1.5 in order to investigate the influence of DS on physicochemical, drug release and mucoadhesion properties as well as interactions with gastrointestinal tract (GIT) epithelial barrier models. Placebo and furosemide loaded CMS-MS were obtained by emulsion-crosslinking with sodium trimetaphosphate (STMP). DS had an impact on increasing equilibrium water uptake and modulating drug release properties of the CMS-MS according to the surrounding pH. The transepithelial electrical resistance (TEER) of NCI-N87 gastric cell monolayers was not influenced in presence of CMS-MS, whereas that of Caco-2 intestinal cell monolayers decreased with increasing DS but recovered initial values at about 15h post-treatment. CMS-MS with increasing DS also enhanced furosemide permeability across both NCI-N87 and Caco-2 monolayers at pH gradients from 3.0 to 7.4. Mucoadhesion of CMS-MS on gastric mucosa (acidic condition) increased with the DS up to 55% for a DS of 1.0 but decreased on neutral intestinal mucosa to less than 10% with DS of 0.1. The drug release, permeability enhancement and mucoadhesive properties of the CMS-MS suggest CMS-MS with DS between 0.6 and 1.0 as suitable excipient for gastroretentive oral delivery dosage forms. PMID:26456246

  15. RhBMP-2 microspheres-loaded chitosan/collagen scaffold enhanced osseointegration: an experiment in dog.

    PubMed

    Shi, Shanshan; Cheng, Xiangrong; Wang, Jiawei; Zhang, Wei; Peng, Lin; Zhang, Yufeng

    2009-01-01

    The purpose of this study is to develop a novel recombinant human bone morphogenetic protein-2 (rhBMP-2) sustained release scaffold for dental implant osseointegration, and to evaluate the effect of this scaffold on promoting bone formation. RhBMP-2 was encapsulated in the poly-D,L-lactide-co-glycolide (PLGA) biodegradable microspheres, which were subsequently dispersed in a chitosan/collagen composite scaffold. This rhBMP-2 microspheres-loaded scaffold (S-MB) was compared with a chitosan/collagen scaffold without microspheres that directly encapsulated rhBMP-2 (S-B) in vitro and in vivo. The microstructure of the new scaffold was examined with scanning electron microscopy. The release profile of rhBMP-2 in vitro was measured at interval periods. The effect of rhBMP-2 encapsulated scaffolds on enhancing bone formation through implantation in dogs' mandibles was identified by histological examination of the regenerated bone after 4 weeks of implantation. Due to PLGA microspheres being loaded, the S-MB exhibited lower values at porosity and swelling rate, as well as a higher effective release dose than that of the S-B. Bone density, bone-implant contact, and bone-fill values measured from dog experiments demonstrated that the S-MB induced bone regeneration more quickly and was timely substituted by new bone. It was concluded that this sustained carrier scaffold based on microspheres was more effective to induce implant osseointegration. PMID:18667455

  16. Biosensing by WGM Microspherical Resonators.

    PubMed

    Righini, Giancarlo C; Soria, Silvia

    2016-01-01

    Whispering gallery mode (WGM) microresonators, thanks to their unique properties, have allowed researchers to achieve important results in both fundamental research and engineering applications. Among the various geometries, microspheres are the simplest 3D WGM resonators; the total optical loss in such resonators can be extremely low, and the resulting extraordinarily high Q values of 10⁸-10⁸ lead to high energy density, narrow resonant-wavelength lines and a lengthy cavity ringdown. They can also be coated in order to better control their properties or to increase their functionality. Their very high sensitivity to changes in the surrounding medium has been exploited for several sensing applications: protein adsorption, trace gas detection, impurity detection in liquids, structural health monitoring of composite materials, detection of electric fields, pressure sensing, and so on. In the present paper, after a general introduction to WGM resonators, attention is focused on spherical microresonators, either in bulk or in bubble format, to their fabrication, characterization and functionalization. The state of the art in the area of biosensing is presented, and the perspectives of further developments are discussed. PMID:27322282

  17. Biosensing by WGM Microspherical Resonators

    PubMed Central

    Righini, Giancarlo C.; Soria, Silvia

    2016-01-01

    Whispering gallery mode (WGM) microresonators, thanks to their unique properties, have allowed researchers to achieve important results in both fundamental research and engineering applications. Among the various geometries, microspheres are the simplest 3D WGM resonators; the total optical loss in such resonators can be extremely low, and the resulting extraordinarily high Q values of 108–109 lead to high energy density, narrow resonant-wavelength lines and a lengthy cavity ringdown. They can also be coated in order to better control their properties or to increase their functionality. Their very high sensitivity to changes in the surrounding medium has been exploited for several sensing applications: protein adsorption, trace gas detection, impurity detection in liquids, structural health monitoring of composite materials, detection of electric fields, pressure sensing, and so on. In the present paper, after a general introduction to WGM resonators, attention is focused on spherical microresonators, either in bulk or in bubble format, to their fabrication, characterization and functionalization. The state of the art in the area of biosensing is presented, and the perspectives of further developments are discussed. PMID:27322282

  18. Nasal administration of ondansetron using a novel microspheres delivery system.

    PubMed

    Mahajan, Hitendra S; Gattani, Surendra G

    2009-01-01

    Gellan gum microspheres of ondansetron hydrochloride, for intranasal delivery, were prepared to avoid the first pass metabolism as an alternative therapy to parentral, and to improve therapeutic efficiency in treatment of nausea and vomiting. The microspheres were prepared using conventional spray-drying method. The microspheres were evaluated for characteristics like particle size, incorporation efficiency, swelling ability, zeta potential, in-vitro mucoadhesion, thermal analysis, XRD study and in-vitro drug release. Treatment of in-vitro data to different kinetic equations indicated diffusion controlled drug delivery from gellan gum microspheres. The results of DSC and XRD studies revealed molecular amorphous dispersion of ondansetron into the gellan gum microspheres. PMID:19519195

  19. Acrolein Microspheres Are Bonded To Large-Area Substrates

    NASA Technical Reports Server (NTRS)

    Rembaum, Alan; Yen, Richard C. K.

    1988-01-01

    Reactive cross-linked microspheres produced under influence of ionizing radiation in aqueous solutions of unsaturated aldehydes, such as acrolein, with sodium dodecyl sulfate. Diameters of spheres depend on concentrations of ingredients. If polystyrene, polymethylmethacrylate, or polypropylene object immersed in solution during irradiation, microspheres become attached to surface. Resulting modified surface has grainy coating with reactivity similar to free microspheres. Aldehyde-substituted-functional microspheres react under mild conditions with number of organic reagents and with most proteins. Microsphere-coated macrospheres or films used to immobilize high concentrations of proteins, enzymes, hormones, viruses, cells, and large number of organic compounds. Applications include separation techniques, clinical diagnostic tests, catalytic processes, and battery separators.

  20. Improving photoprotection: 4-methylbenzylidene camphor microspheres.

    PubMed

    Centini, Marisanna; Miraglia, Giovanna; Quaranta, Valeria; Buonocore, Anna; Anselmi, Cecilia

    2014-05-22

    Abstract We propose a new approach for photoprotection. 4-Methylbenzylidene camphor (4-MBC), one of the most widely used UV filters, was encapsulated in microspheres, with a view to overcoming problems (percutaneous absorption, photodegradation and lack of lasting effect) arising with organic sunscreens, and to achieve safe photoprotection. We focused on this filter in the light of the Cosmetics Europe opinion concerning its possible effects on the thyroid gland. Microspheres were prepared by emulsification-solvent evaporation, using different amounts of 4-MBC and characterized for morphology, encapsulation efficiency and particle size. The particles were then mixed in O/W emulsions. The in vitro sun protection factors, in vitro release and photostability were investigated and compared with emulsions containing the free sunscreen. The new microspheres offer good morphology and loading (up to 40%), and the same photoprotection as the free filter while at the same time protecting it from photodegradation. The systems also give a slower release from the emulsions. PMID:24854342

  1. Gastrointestinal care for older people.

    PubMed

    Tremayne, Penny; Harrison, Penny

    2016-07-01

    This article discusses gastrointestinal (GI) healthcare in older people. It outlines the physiological changes that occur in the GI tract as a result of ageing, and discusses common GI disorders in older people. These GI disorders include dysphagia, gastrointestinal reflux disease, colorectal cancer, diverticular disease, constipation and anaemia. Healthcare professionals should be aware of the factors that may influence gastrointestinal health in older people, including nutrition, hydration and alcohol use, which are important considerations when delivering person-centred care. PMID:27380703

  2. Alternating current electrokinetic properties of gold-coated microspheres.

    PubMed

    García-Sánchez, Pablo; Ren, Yukun; Arcenegui, Juan J; Morgan, Hywel; Ramos, Antonio

    2012-10-01

    We present dielectrophoresis (DEP) and electrorotation (ROT) measurements of gold-coated polystyrene microspheres as a function of frequency and for several electrolyte conductivities. Particle rotation was counterfield with a maximum rotation rate observed at a single characteristic frequency. Negative DEP was observed for frequencies lower than this characteristic frequency and positive DEP for signal frequencies higher than this. These experimental observations are in agreement with predictions for the force and torque on the induced dipole of a perfectly polarizable metal sphere. We present a theoretical model for this case, and good agreement is found for both ROT and DEP measurements if we take into account the viscous friction for a spherical particle near a wall. From the characteristic frequency for rotation, we obtain the capacitance of the electrical double layer at the electrolyte-particle interface. Remarkably, no effect of induced charge electroosmosis around the particles can be inferred from DEP measurements. PMID:22931290

  3. Polymeric microspheres as protein transduction reagents.

    PubMed

    Nagel, David; Behrendt, Jonathan M; Chimonides, Gwen F; Torr, Elizabeth E; Devitt, Andrew; Sutherland, Andrew J; Hine, Anna V

    2014-06-01

    Discovering the function of an unknown protein, particularly one with neither structural nor functional correlates, is a daunting task. Interaction analyses determine binding partners, whereas DNA transfection, either transient or stable, leads to intracellular expression, though not necessarily at physiologically relevant levels. In theory, direct intracellular protein delivery (protein transduction) provides a conceptually simpler alternative, but in practice the approach is problematic. Domains such as HIV TAT protein are valuable, but their effectiveness is protein specific. Similarly, the delivery of intact proteins via endocytic pathways (e.g. using liposomes) is problematic for functional analysis because of the potential for protein degradation in the endosomes/lysosomes. Consequently, recent reports that microspheres can deliver bio-cargoes into cells via a non-endocytic, energy-independent pathway offer an exciting and promising alternative for in vitro delivery of functional protein. In order for such promise to be fully exploited, microspheres are required that (i) are stably linked to proteins, (ii) can deliver those proteins with good efficiency, (iii) release functional protein once inside the cells, and (iv) permit concomitant tracking. Herein, we report the application of microspheres to successfully address all of these criteria simultaneously, for the first time. After cellular uptake, protein release was autocatalyzed by the reducing cytoplasmic environment. Outside of cells, the covalent microsphere-protein linkage was stable for ≥90 h at 37 °C. Using conservative methods of estimation, 74.3% ± 5.6% of cells were shown to take up these microspheres after 24 h of incubation, with the whole process of delivery and intracellular protein release occurring within 36 h. Intended for in vitro functional protein research, this approach will enable study of the consequences of protein delivery at physiologically relevant levels, without recourse to

  4. Redox-responsive alginate microsphere containing cystamine.

    PubMed

    Kwon, Kyeongnan; Kim, Jin-Chul

    2016-10-01

    Redox-responsive microspheres were prepared by solidifying the alginate- and cystamine-containing water droplets of O/W emulsion using calcium ion. Emulsions were prepared using alginate/cystamine mixture solution whose the carboxylic group/the amino group molar ratio was 1:1, 1:2, and 1:3, and whose the total concentration was kept to 2% (w/v). The microspheres on Scanning electron microscopy photographs were almost spherical and they were less than 1 μm in diameter. According to the energy-dispersive X-ray spectroscopy, the sulfur content of the microspheres was found to be 6.1, 11.4, and 14.8% (w/w), respectively, not markedly different from the calculated content. The release degree of blue dextran loaded in the microspheres was higher as the cystamine content was higher. Microspheres released almost the same amount of dye regardless of dithiothreitol (DTT, a reducing agent) concentration when the cystamine content was relatively low (e.g. 14.5% (w/w)), whereas they released dye in DTT concentration-dependent manner when the cystamine content was relatively high (e.g. 27.0 and 35.1% (w/w)). The light scattering intensity of alginate/cystamine mixture solution was stronger at a larger amount of cystamine, indicating that cystamine could cross-link alginate chains. The light scattering intensity decreased with increasing DTT concentration, possibly because of the breakdown of the disulfide bond of cystamine. The breakdown of the disulfide bond could account for why the DTT concentration-dependent release of dye loaded in the microspheres was observed. PMID:27484719

  5. Role of nitric oxide in the gastrointestinal tract

    PubMed Central

    Lanas, Angel

    2008-01-01

    Worldwide osteoarthritis (OA) affects more than 9.6% of men and 18% of women older that 60 years. Treatment for OA often requires chronic use of selective or nonselective nonsteroidal anti-inflammatory drugs (NSAIDs), which have been associated with gastrointestinal and cardiovascular complications. An increased risk for upper gastrointestinal bleeding with NSAIDs alone and when combined with low-dose aspirin has been described in numerous studies. Although cyclo-oxygenase-2 inhibitors have been shown to carry a lower risk for gastrointestinal injury than nonselective NSAIDs, research continues to identify new treatments that not only are effective but also provide an improved benefit/risk profile, including better gastrointestinal tolerability. Nitric oxide (NO) is known to have a protective effect on the gastrointestinal tract. In preclinical studies NO was shown to help maintain gastric mucosal integrity, to inhibit leukocyte adherence to the endothelium, and to repair NSAID-induced damage. In addition, epidemiologic studies have shown that the use of NO-donating agents with NSAIDs or aspirin resulted in reduced risk for gastrointestinal bleeding. Recent studies have shown that cyclo-oxygenase inhibiting NO-donating drugs (CINODs), in which a NO molecule is chemically linked to an NSAID, are effective anti-inflammatory agents and may result in less gastrointestinal damage than is associated with NSAID use. Therefore, these agents provide a potential therapeutic option for patients with arthritis who require long-term NSAID therapy. PMID:19007429

  6. Gastrointestinal Manifestations of Cystic Fibrosis

    PubMed Central

    2016-01-01

    Cystic fibrosis has historically been considered a pulmonary disease, but with the increasing life expectancy of these patients, gastrointestinal manifestations are becoming more important. Furthermore, nutritional status is closely linked to pulmonary function and, thus, overall mortality. This article discusses gastrointestinal manifestations (which involve nutritional, pancreatic, hepatobiliary, and, in particular, gastrointestinal tract issues) of cystic fibrosis as well as management of the disease. In addition, the article discusses studies that have been critical to our understanding of gastrointestinal manifestations of cystic fibrosis. PMID:27330503

  7. Polymer-functionalised microspheres for immunosensing applications

    NASA Astrophysics Data System (ADS)

    Soria, S.; Baldini, F.; Berneschi, S.; Brenci, M.; Cosi, F.; Giannetti, A.; Nunzi conti, G.; Pelli, S.; Righini, G. C.; Tiribilli, B.

    2010-02-01

    Homogeneous polymeric thin layers have been used as functionalising agents on silica microresonators in view of immunosensing applications. We have characterised the microspheres functionalised with poly-L-lactic acid and Eudragit® L100, as an alternative to the commonly used silanes. It is shown that after polymeric functionalization the quality factor of the silica microspheres remains around 107, and that the Q factor is still about 3x105 after chemical activation and covalent binding of immunogammaglobulin. This functionalising process of the microresonator constitutes a promising step towards the achievement of a highly sensitive immunosensor.

  8. Unusual imaging properties of superresolution microspheres.

    PubMed

    Li, Pin-Yi; Tsao, Yang; Liu, Yun-Ju; Lou, Zong-Xing; Lee, Wei-Li; Chu, Shi-Wei; Chang, Chih-Wei

    2016-07-25

    We employ a self-assembly method to fabricate dielectric microsphere arrays that can be transferred to any desired positions. The arrays not only enable far-field, broad-band, high-speed, large-area, and wide-angle field of views but also achieve superresolution reaching λ/6.4. We also find that many proposed theories are insufficient to explain the imaging properties; including the achieved superresolution, effects of immersion, and unusual size-dependent magnification. The half-immersed microspheres certainly do not behave like any ordinary solid immersion lenses and new mechanisms must be incorporated to explain their unusual imaging properties. PMID:27464101

  9. Cell specific, variable density, polymer microspheres

    NASA Technical Reports Server (NTRS)

    Yen, Shiao-Ping S. (Inventor); Rembaum, Alan (Inventor); Molday, Robert S. (Inventor)

    1977-01-01

    Biocompatible polymeric microspheres having an average diameter below about 3 microns and having density at least 15% greater or lesser than organic cells and having covalent binding sites are provided in accordance with this invention. The microspheres are obtained by copolymerizing a hydroxy or amine substituted acrylic monomer such as hydroxyethylmethacrylate with a light or dense comonomer such as a fluoromonomer. A lectin or antibody is bound to the hydroxy or amine site of the bead to provide cell specificity. When added to a cell suspension the marked bead will specifically label the cell membrane by binding to specific receptor sites thereon. The labelled membrane can then be separated by density gradient centrifugation.

  10. Electrophoretic cell separation by means of microspheres

    NASA Technical Reports Server (NTRS)

    Smolka, A. J. K.; Nerren, B. H.; Margel, S.; Rembaum, A.

    1979-01-01

    The electrophoretic mobility of fixed human erythrocytes immunologically labeled with poly(vinylpyridine) or poly(glutaraldehyde) microspheres was reduced by approximately 40%. This observation was utilized in preparative scale electrophoretic separations of fixed human and turkey erythrocytes, the mobilities of which under normal physiological conditions do not differ sufficiently to allow their separation by continuous flow electrophoresis. We suggest that resolution in the electrophoretic separation of cell subpopulations, currently limited by finite and often overlapping mobility distributions, may be significantly enhanced by immunospecific labeling of target populations using microspheres.

  11. Quantum Magnetomechanics with Levitating Superconducting Microspheres

    NASA Astrophysics Data System (ADS)

    Romero-Isart, O.; Clemente, L.; Navau, C.; Sanchez, A.; Cirac, J. I.

    2012-10-01

    We show that by magnetically trapping a superconducting microsphere close to a quantum circuit, it is possible to perform ground-state cooling and prepare quantum superpositions of the center-of-mass motion of the microsphere. Due to the absence of clamping losses and time-dependent electromagnetic fields, the mechanical motion of micrometer-sized metallic spheres in the Meissner state is predicted to be very well isolated from the environment. Hence, we propose to combine the technology of magnetic microtraps and superconducting qubits to bring relatively large objects to the quantum regime.

  12. Management of gastrointestinal haemorrhage

    PubMed Central

    Ghosh, S; Watts, D; Kinnear, M

    2002-01-01

    A variety of endoscopic haemostatic techniques have enabled major advances in the management of not only bleeding peptic ulcers and bleeding varices, but also in a variety of bleeding lesions in the small intestine and in the colon. Indeed, the development and widespread implementation of endoscopic haemostasis has been one of the most important developments in clinical gastroenterology in the past two decades. An increasingly ageing cohort of patients with multiple co-morbidity are being treated and therefore improving the outcome of gastrointestinal bleeding continues to pose major challenges. PMID:11796865

  13. Laser velocimetry with fluorescent dye-doped polystyrene microspheres.

    PubMed

    Lowe, K Todd; Maisto, Pietro; Byun, Gwibo; Simpson, Roger L; Verkamp, Max; Danehy, Paul M; Tiemsin, Pacita I; Wohl, Christopher J

    2013-04-15

    Simultaneous Mie scattering and laser-induced fluorescence (LIF) signals are obtained from individual polystyrene latex microspheres dispersed in an air flow. Microspheres less than 1 μm mean diameter were doped with two organic fluorescent dyes, Rhodamine B (RhB) and dichlorofluorescein (DCF), intended either to provide improved particle-based flow velocimetry in the vicinity of surfaces or to provide scalar flow information (e.g., marking one of two fluid streams). Both dyes exhibit measureable fluorescence signals that are on the order of 10(-3) to 10(-4) times weaker than the simultaneously measured Mie signals. It is determined that at the conditions measured, 95.5% of RhB LIF signals and 32.2% of DCF signals provide valid laser-Doppler velocimetry measurements compared with the Mie scattering validation rate with 6.5 W of 532 nm excitation, while RhB excited with 1.0 W incident laser power still exhibits 95.4% valid velocimetry signals from the LIF channel. The results suggest that the method is applicable to wind tunnel measurements near walls where laser flare can be a limiting factor and monodisperse particles are essential. PMID:23595429

  14. Bioactive Microsphere-Based Scaffolds Containing Decellularized Cartilage.

    PubMed

    Sutherland, Amanda J; Detamore, Michael S

    2015-07-01

    The aim of this study was to fabricate mechanically functional microsphere-based scaffolds containing decellularized cartilage (DCC), with the hypothesis that this approach would induce chondrogenesis of rat bone marrow-derived mesenchymal stem cells (rBMSCs) in vitro. The DCC was derived from porcine articular cartilage and decellularized using a combination of physical and chemical methods. Four types of scaffolds were fabricated: poly(d,l-lactic-co-glycolic acid) (PLGA) only (negative control), TGF-β-encapsulated (positive control), PLGA surface coated with DCC, and DCC-encapsulated. These scaffolds were seeded with rBMSCs and cultured up to 6 weeks. The compressive modulus of the DCC-coated scaffolds prior to cell seeding was significantly lower than all other scaffold types. Gene expression was comparable between DCC-encapsulated and TGF-β-encapsulated groups. Notably, DCC-encapsulated scaffolds contained 70% higher glycosaminoglyan (GAG) content and 85% more hydroxyproline compared to the TGF-β group at week 3 (with baseline levels subtracted out from acellular DCC scaffolds). Certainly, bioactivity was demonstrated in eliciting a biosynthetic response from the cells with DCC, although true demonstration of chondrogenesis remained elusive under the prescribed conditions. Encapsulation of DCC appeared to lead to improved cell performance relative to coating with DCC, although this finding may be a dose-dependent observation. Overall, DCC introduced via microsphere-based scaffolds appears to be promising as a bioactive approach to cartilage regeneration, although additional studies will be required to conclusively demonstrate chondroinductivity. PMID:25821206

  15. Intravital Microscopic Research of Microembolization with Degradable Starch Microspheres

    PubMed Central

    Ebert, Juergen; Berger, Gerd

    2013-01-01

    Treatment efficacy in cancer patients using systemically applied cytostatic drugs is decreased by cytotoxic side effects, which limits the use of efficient dosages. Degradable starch microspheres (DSM) are used to apply drugs into blood vessels which supply the target organ leading to drug accumulation in the target organ by reduction of the blood flow. The present investigations show that DSM is a very effective embolization material leading to effective and enhanced accumulation of 5-FU within the liver tumor tissue of experimental induced liver cancer in rats. By using intravital microscopy, a rapid deceleration of the blood flow into the target organ is observed immediately after application of DSM. The microspheres are stepwise degraded in the direction of the systemic blood flow and are totally dissolved after 25 minutes. These stepwise processes leave the degraded material during the degradation process within the vessels leading to temporally reciprocal blood flow via some of the side-arms of the major blood vessels. By using DMS in transarterial chemoembolization (TACE), severe adverse side effects like postembolization syndrome are rarely observed when compared to other embolization materials. The complete degradation of DSM causes only a short-lasting temporary vascular occlusion, which allows a repeat application of DSM in TACE. PMID:24324891

  16. Injectable polymer microspheres enhance immunogenicity of a contraceptive peptide vaccine.

    PubMed

    Cui, Chengji; Stevens, Vernon C; Schwendeman, Steven P

    2007-01-01

    Advanced contraceptive peptide vaccines suffer from the unavailability of adjuvants capable of enhancing the antibody response with acceptable safety. We sought to overcome this limitation by employing two novel poly(lactic-co-glycolic acid) (PLGA) microsphere formulations to deliver a synthetic human chorionic gonadotropin (hCG) peptide antigen co-synthesized with a T-cell epitope from tetanus toxoid (TT), C-TT2-CTP35: surface-conjugated immunogen to induce phagocytosis; and encapsulated peptide to provide a depot effect, with MgCO(3) co-encapsulated in the polymer to neutralize acidity from the biodegrading PLGA polyester. A single immunization of encapsulated peptide in rabbits elicited a stronger antibody response with equivalent duration relative to a positive control--three injections of the peptide administered in a squalene-based water-in-oil emulsion. Surface-conjugated peptide was less effective but enhanced antibody levels at 1/5 the dose, relative to soluble antigen. Most remarkable and unexpected was the finding that co-encapsulation of base was essential to attain the powerful adjuvant effect of the PLGA-MgCO(3) system, as the MgCO(3)-free microspheres were completely ineffective. A promising contraceptive hCG peptide vaccine with acceptable side effects (i.e., local tissue reactions) was achieved by minimizing PLGA and MgCO(3) doses, without significantly affecting antibody response. PMID:16996662

  17. PLGA microspheres for the delivery of a novel subunit TB vaccine.

    PubMed

    Kirby, Daniel J; Rosenkrands, Ida; Agger, Else M; Andersen, Peter; Coombes, Allan G A; Perrie, Yvonne

    2008-05-01

    Biodegradable poly(dl-lactide-co-glycolide) microspheres were prepared using a modified double emulsion solvent evaporation method for the delivery of the subunit tuberculosis vaccine (Ag85B-ESAT-6), a fusion protein of the immunodominant antigens 6-kDa early secretory antigenic target (ESAT-6) and antigen 85B (Ag85B). Addition of the cationic lipid dimethyl dioctadecylammonium bromide (DDA) and the immunostimulatory trehalose 6,6'-dibehenate (TDB), either separately or in combination, was investigated for the effect on particle size and distribution, antigen entrapment efficiency, in vitro release profiles and in vivo performance. Optimised formulation parameters yielded microspheres within the desired sub-10 microm range (1.50 +/- 0.13 microm), whilst exhibiting a high antigen entrapment efficiency (95 +/- 1.2%) and prolonged release profiles. Although the microsphere formulations induced a cell-mediated immune response and raised specific antibodies after immunisation, this was inferior to the levels achieved with liposomes composed of the same adjuvants (DDA-TDB), demonstrating that liposomes are more effective vaccine delivery systems compared with microspheres. PMID:18446607

  18. Effect of Eu, Tb codoping on the luminescent properties of Y2O3 hollow microspheres

    NASA Astrophysics Data System (ADS)

    Jiu, Hongfang; Fu, Yuehua; Zhang, Lixin; Sun, Yixin; Wang, Yuanzhong

    2012-12-01

    Y2O3:Eu3+, Tb3+ hollow microspheres are prepared with different doping concentration of Eu3+ and Tb3+ ions and synthesizing temperatures from 700 to 1000 °C via a urea-based homogeneous precipitation technique with colloidal melamine formaldehyde (MF) microspheres as templates followed by a subsequent calcination process. The resulted hollow microspheres were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and photoluminescence (PL) spectroscopy. The results of XRD indicate that the crystallinity of the synthesized samples increases with enhancing the calcination temperature. The photoluminescence spectra indicate the Eu3+ and Tb3+ co-doped Y2O3 microspheres show five main emission peaks: three at 591, 609 and 629 nm originate from Eu3+ and two at 482 and 541 nm originate from Tb3+, under excitation of 250-340 nm irradiation. The luminescence color could be changed by varying the excitation wavelength. Different concentrations of Eu3+ and Tb3+ ions were induced into the Y2O3 lattice and the energy transfer from Tb3+ to Eu3+ ions in these phosphors was found.

  19. Binary breath figures for straightforward and controllable self-assembly of microspherical caps.

    PubMed

    Gong, Jianliang; Xu, Bingang; Tao, Xiaoming; Li, Lei

    2016-05-11

    The intense interest surrounding asymmetrical microparticles originates from their unique anisotropic properties and promising applications. In this work, direct self-assembly of polymeric microspherical caps without the assistance of any additives has been achieved by using low-surface-tension methanol (MeOH) and high-surface-tension water as binary breath figures (BFs). With the evaporation of polystyrene (PS) solution containing low-boiling-point solvent in the binary vapors, the formed MeOH BFs could quickly diffuse into solution, while water BFs tended to remain at the solution surface. This led to the formation of a gradient nonsolvent layer at the vapor/solution interface, which induced the formation of nuclei and guided further asymmetrical growth of polymer particles. After the spontaneous removal of MeOH, water and residual solvent by evaporation, polymeric microspherical caps were left on the substrate. Through controlling the proportion of water introduced by adjusting the ratios of MeOH and water, polymeric microspherical caps with a range of controllable shapes (divided at different positions of a sphere) were successfully obtained. The formation mechanism was explained based on the difference of vapor pressure, surface tension and miscibility between the employed solvents and nonsolvents. A solvent possessing a high vapor pressure, low surface tension and good miscibility with MeOH contributed to the formation of microspherical caps. This flexible, green and straightforward technique is a nondestructive strategy, and avoids complicated work on design, preparation and removal of hard templates and additives. PMID:27139817

  20. [Preparation and application of solid phase extraction packing of zirconia microsphere coated with sulfonated crosslinked polystyrene].

    PubMed

    Shen, Shuchang; Liu, Yuhui; Xiao, Xiaoxing

    2013-08-01

    Zirconia microsphere was prepared by polymerization-induced colloid aggregation (PICA) method and carbon-carbon double bond was grafted onto its surface by titanic acid ester coupling reagent. Poly(styrene-divinylbenzene) was synthesized by free radical polymerization by using styrene, divinylbenzene and carbon-carbon double bond on the microsphere surface in solution system, so the polymer was coated on the microsphere surface. After the benzene ring of the polymer was sulfonated, the cation exchange packing for solid phase extraction (SPE) was obtained. The material was characterized by Fourier transform infrared spectroscopy, scanning electron microscope and X-ray energy dispersive spectroscopy. Three herbicides of mesotrione, atrazine and acetochlor in water were determined by the SPE cartridge coupled with high performance liquid chromatography (HPLC). In the range of 0.5 - 3.0 mg/L, the relationships between the peak areas and mass concentrations of mesotrione, atrazine and acetochlor were linear with the correlation coefficients of 0.9936, 0.9925, 0.9919, respectively. The limits of detection were 5.41, 6.72 and 13.4 microg/L for mesotrione, atrazine and acetochlor, respectively. The results showed that the zirconium dioxide microspheres coated with polymer have diameters in the range of about 6 to 8 microm, the SPE cartridges of which have high adsorption rate for the targets. PMID:24369611

  1. Nanofibrous spongy microspheres enhance odontogenic differentiation of human dental pulp stem cells.

    PubMed

    Kuang, Rong; Zhang, Zhanpeng; Jin, Xiaobing; Hu, Jiang; Gupte, Melanie J; Ni, Longxing; Ma, Peter X

    2015-09-16

    Dentin regeneration is challenging due to its complicated anatomical structure and the shortage of odontoblasts. In this study, a novel injectable cell carrier, nanofibrous spongy microspheres (NF-SMS), is developed for dentin regeneration. Biodegradable and biocompatible poly(l-lactic acid)-block-poly(l-lysine) are synthesized and fabricated into NF-SMS using self-assembly and thermally induced phase separation techniques. It is hypothesized that NF-SMS with interconnected pores and nanofibers can enhance the proliferation and odontogenic differentiation of human dental pulp stem cells (hDPSCs), compared to nanofibrous microspheres (NF-MS) without pore structure and conventional solid microspheres (S-MS) with neither nanofibers nor pore structure. During the first 9 d in culture, hDPSCs proliferate significantly faster on NF-SMS than on NF-MS or S-MS (p < 0.05). Following in vitro odontogenic induction, all the examined odontogenic genes (alkaline phosphatase content, osteocalcin, bone sialoprotein, collagen 1, dentin sialophosphoprotein (DSPP)), calcium content, and DSPP protein content are found significantly higher in the NF-SMS group than in the control groups. Furthermore, 6 weeks after subcutaneous injection of hDPSCs and microspheres into nude mice, histological analysis shows that NF-SMS support superior dentin-like tissue formation compared to NF-MS or S-MS. Taken together, NF-SMS have great potential as an injectable cell carrier for dentin regeneration. PMID:26138254

  2. Lower gastrointestinal bleeding.

    PubMed

    Silber, G

    1990-09-01

    The differential diagnosis of lower gastrointestinal bleeding in children can be reduced markedly simply by taking into account the age of the child. The clinical condition of the patient can further help narrow the diagnostic possibilities. Newborns and infants who are clinically unstable are more likely to have diseases such as necrotizing enterocolitis, volvulus, Hirschprung disease, intussusception, or Meckel diverticulum. A baby who appears healthy should be examined for swallowed blood, allergic colitis, anal fissures, or lymphonodular hyperplasia. An older child of healthy appearance with bleeding is likely to have a juvenile polyp or infectious colitis, but a child who appears sick may have hemolytic uremic syndrome, Henoch-Schoenlein purpura, or inflammatory bowel disease. This information, along with that gleaned from the physical examination, can lead the pediatrician to determine the need for specific tests, such as abdominal radiographs, stool cultures, and an endoscopic evaluation. We have come a long way in our ability to diagnose the causes of lower gastrointestinal bleeding. With the availability of newer radiographic and nuclear medicine modalities and the ability to visualize the colon endoscopically, the need for exploratory laparotomy for diagnosis is rarer. While surgery may still be the therapy of choice, new diagnostic modalities give the surgeon much more preoperative information. PMID:2235771

  3. Micronutrients in gastrointestinal cancer.

    PubMed

    Georgiannos, S N; Weston, P M; Goode, A W

    1993-12-01

    The monitoring of micronutrients and the relationship between dietary intake and micronutrient status prior to and after surgery in patients with histologically proven gastrointestinal adenocarcinoma, both weight-stable and weight-losing (> 7.5% of their pre-illness weight) has been studied and the results compared to controls. Plasma vitamin C and red blood cell thiamine levels were significantly lower in weight-losing cancer patients when compared to their weight-stable counterparts (P < 0.05 and P < 0.02 respectively). Weight-losing patients had a lower vitamin C (P < 0.05) and thiamine (P < 0.002) intake, and a higher elevation in plasma C-reactive protein and a lower prealbumin level (P < 0.02), when compared to both weight-stable cancer patients and controls. Plasma vitamin C, prealbumin and C-reactive protein levels remained unchanged after curative resections of the tumours compared to a preoperative value, and there was a highly significant correlation between plasma vitamin C and dietary intake of vitamin C. This study suggests that the lower vitamin C and thiamine status in weight-losing gastrointestinal cancer patients prior to surgery is due to a lower micronutrient intake and an acute phase response to their illness. Dietary intake of vitamin C appears to be the major factor in determining plasma vitamin C concentration following curative surgical resection. PMID:8260373

  4. Nutritional Status, Body Surface, and Low Lean Body Mass/Body Mass Index Are Related to Dose Reduction and Severe Gastrointestinal Toxicity Induced by Afatinib in Patients With Non-Small Cell Lung Cancer

    PubMed Central

    De la Torre-Vallejo, Martha; López-Macías, Diego; Orta, David; Turcott, Jenny; Macedo-Pérez, Eleazar-Omar; Sánchez-Lara, Karla; Ramírez-Tirado, Laura-Alejandra; Baracos, Vickie E.

    2015-01-01

    Background. The main reason for dose reduction of afatinib is gastrointestinal toxicity (GT). In a phase II study, we analyzed anthropometrical, nutritional, and biochemical factors associated with GT induced by afatinib. Materials and Methods. Patients diagnosed with non-small cell lung cancer who progressed to prior chemotherapy received 40 mg of afatinib. Malnutrition was determined by Subjective Global Assessment, and lean body mass (LBM) was determined by computed tomography scan analysis using a pre-established Hounsfield unit threshold. Toxicity was obtained during four cycles by Common Terminology Criteria for Adverse Events. Results. Eighty-four patients were enrolled. Afatinib was administered as the second, third, and fourth line of treatment in 54.8%, 38.1%, and 7.12% of patients, respectively. Severe diarrhea, mucositis, and overall severe GT were present in 38.9%, 28.8%, and 57.5%, respectively. Of the patients, 50% developed dose-limiting toxicity (DLT). Patients with malnutrition have higher risk for severe GT. Patients with lower LBM and body mass index developed more DLT (71.4% vs. 18.8%). Conclusion. Malnutrition is associated with a higher risk of severe GT induced by afatinib. Determination of nutritional status and body composition are helpful in identifying patients at higher risk of severe GT and could allow initiating treatment with lower doses according to tolerance. Implications for Practice: Body composition analysis, specifically lean body mass quantification, and nutritional status assessment are significant clinical variables to take into account when assessing oncological patients. This study on patients with non-small cell lung cancer treated with afatinib showed the important impact that malnutrition and low lean body mass have on the risk for developing dose-limiting toxicity and severe gastrointestinal toxicity. Still more research needs to be done to explore dose adjustment according to lean body mass, especially in drugs that

  5. Curcumin Ameliorates Reserpine-Induced Gastrointestinal Mucosal Lesions Through Inhibiting IκB-α/NF-κB Pathway and Regulating Expression of Vasoactive Intestinal Peptide and Gastrin in Rats.

    PubMed

    Long, Lingli; Wang, Jingnan; Chen, Ningning; Zheng, Shuhui; Shi, Lanying; Xu, Yuxia; Luo, Canqiao; Deng, Yubin

    2016-06-01

    The objective of our study was to investigate whether curcumin protects against reserpine-induced gastrointestinal mucosal lesions (GMLs) in rats and to explore the mechanism of curcumin's action. Sprague-Dawley rats were randomly divided into four groups: control group, reserpine-treated group, reserpine treatment group with curcumin at high dose (200 mg/kg), and reserpine treatment group with curcumin at low dose (100 mg/kg). Rats in reserpine-treated group were induced by intraperitoneally administered reserpine (0.5 mg/kg) for 28 days. TUNEL staining and hematoxylin and eosin staining were used to evaluate the apoptotic cells and morphologic changes. In addition, to explore the mechanism of curcumin in protecting GMLs, we used serum of experimental rats to assess the level of vasoactive intestinal peptide (VIP), gastrin, interleukin-6, interleukin-10, tumor necrosis factor-α and interferon-γ by ELISA and radioimmunoassay. The protein levels of NF-κB, p-IκB-α, IκB-α, Bcl-2, Bax, and cleaved-caspase-3 were examined by western blot analysis. Data were analyzed with SPSS 19.0 software package. Curcumin treatment prevented tissue damage and cell death in the reserpine-treated rats and effectively decreased inflammatory response and balanced the expression of VIP and gastrin in the reserpine-treated rats. NF-κB, p-IκB-α, Bax, and cleaved-caspase-3 were increased in the reserpine group, but the curcumin high-dose group inhibited them. Curcumin can target the IκB-α/NF-κB pathway to inhibit inflammatory response and regulate the level of VIP and gastrin in reserpine-induced GML rats. PMID:26872103

  6. Microbiota regulate the ability of lung dendritic cells to induce IgA class-switch recombination and generate protective gastrointestinal immune responses

    PubMed Central

    Ruane, Darren; Chorny, Alejo; Lee, Haekyung; Faith, Jeremiah; Pandey, Gaurav; Shan, Meimei; Simchoni, Noa; Rahman, Adeeb; Garg, Aakash; Weinstein, Erica G.; Oropallo, Michael; Gaylord, Michelle; Ungaro, Ryan; Cunningham-Rundles, Charlotte; Alexandropoulos, Konstantina; Mucida, Daniel; Merad, Miriam; Cerutti, Andrea

    2016-01-01

    Protective immunoglobulin A (IgA) responses to oral antigens are usually orchestrated by gut dendritic cells (DCs). Here, we show that lung CD103+ and CD24+CD11b+ DCs induced IgA class-switch recombination (CSR) by activating B cells through T cell–dependent or –independent pathways. Compared with lung DCs (LDC), lung CD64+ macrophages had decreased expression of B cell activation genes and induced significantly less IgA production. Microbial stimuli, acting through Toll-like receptors, induced transforming growth factor-β (TGF-β) production by LDCs and exerted a profound influence on LDC-mediated IgA CSR. After intranasal immunization with inactive cholera toxin (CT), LDCs stimulated retinoic acid–dependent up-regulation of α4β7 and CCR9 gut-homing receptors on local IgA-expressing B cells. Migration of these B cells to the gut resulted in IgA-mediated protection against an oral challenge with active CT. However, in germ-free mice, the levels of LDC-induced, CT–specific IgA in the gut are significantly reduced. Herein, we demonstrate an unexpected role of the microbiota in modulating the protective efficacy of intranasal vaccination through their effect on the IgA class-switching function of LDCs. PMID:26712806

  7. ATRAZINE DOES NOT INDUCE GASTROINTESTINAL DISCOMFORT (PICA) IN RATS AT DOSES THAT INCREASE HPA-AXIS ACTIVATION AND CAUSE CONDITIONED TASTE AVERSION.

    EPA Science Inventory

    Previous work has shown that a single oral administration of atrazine (ATR), a chlorotriazine herbicide, induces dose-dependent increases in plasma adrenocorticotropic hormone (ACTH) and serum corticosterone (CORT), with a NOEL equal to 5mg/kg. The mechanism for these effects ...

  8. Microbiota regulate the ability of lung dendritic cells to induce IgA class-switch recombination and generate protective gastrointestinal immune responses.

    PubMed

    Ruane, Darren; Chorny, Alejo; Lee, Haekyung; Faith, Jeremiah; Pandey, Gaurav; Shan, Meimei; Simchoni, Noa; Rahman, Adeeb; Garg, Aakash; Weinstein, Erica G; Oropallo, Michael; Gaylord, Michelle; Ungaro, Ryan; Cunningham-Rundles, Charlotte; Alexandropoulos, Konstantina; Mucida, Daniel; Merad, Miriam; Cerutti, Andrea; Mehandru, Saurabh

    2016-01-11

    Protective immunoglobulin A (IgA) responses to oral antigens are usually orchestrated by gut dendritic cells (DCs). Here, we show that lung CD103(+) and CD24(+)CD11b(+) DCs induced IgA class-switch recombination (CSR) by activating B cells through T cell-dependent or -independent pathways. Compared with lung DCs (LDC), lung CD64(+) macrophages had decreased expression of B cell activation genes and induced significantly less IgA production. Microbial stimuli, acting through Toll-like receptors, induced transforming growth factor-β (TGF-β) production by LDCs and exerted a profound influence on LDC-mediated IgA CSR. After intranasal immunization with inactive cholera toxin (CT), LDCs stimulated retinoic acid-dependent up-regulation of α4β7 and CCR9 gut-homing receptors on local IgA-expressing B cells. Migration of these B cells to the gut resulted in IgA-mediated protection against an oral challenge with active CT. However, in germ-free mice, the levels of LDC-induced, CT-specific IgA in the gut are significantly reduced. Herein, we demonstrate an unexpected role of the microbiota in modulating the protective efficacy of intranasal vaccination through their effect on the IgA class-switching function of LDCs. PMID:26712806

  9. ATRAZINE DOES NOT INDUCE GASTROINTESTINAL DISCOMFORT (PICA) IN RATS AT DOSES THAT INCREASE ACTH ANDCORTICOSTERONE RELEASE AND CAUSE CONDITIONED TASTE AVERSION.

    EPA Science Inventory

    Previous work has shown that a single oral administration of atrazine (ATR), a chlorotriazine herbicide, induces dose-dependent increases in plasma adrenocorticotropic hormone (ACTH) and serum corticosterone (CORT), with a LOEL of 12.5mg/kg. The mechanism for these effects is unk...

  10. 21 CFR 870.1360 - Trace microsphere.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... within or to an organ. (b) Classification. Class III (premarket approval). (c) Date PMA or notice of completion of a PDP is required. A PMA or notice of completion of a PDP is required to be filed with the Food... other trace microsphere shall have an approved PMA or a declared completed PDP in effect before...

  11. 21 CFR 870.1360 - Trace microsphere.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... within or to an organ. (b) Classification. Class III (premarket approval). (c) Date PMA or notice of completion of a PDP is required. A PMA or notice of completion of a PDP is required to be filed with the Food... other trace microsphere shall have an approved PMA or a declared completed PDP in effect before...

  12. Beat-Frequency/Microsphere Medical Ultrasonic Imaging

    NASA Technical Reports Server (NTRS)

    Yost, William T.; Cantrell, John H.; Pretlow, Robert A., III

    1995-01-01

    Medical ultrasonic imaging system designed to provide quantitative data on various flows of blood in chambers, blood vessels, muscles, and tissues of heart. Sensitive enough to yield readings on flows of blood in heart even when microspheres used as ultrasonic contrast agents injected far from heart and diluted by circulation of blood elsewhere in body.

  13. Method for introduction of gases into microspheres

    DOEpatents

    Hendricks, C.D.; Koo, J.C.; Rosencwaig, A.

    A method is described for producing small hollow glass spheres filled with a gas by introduction of the gas during formation of the hollow glass spheres. Hollow glass microspheres having a diameter up to about 500..mu.. with both thin walls (0.5 to 4/sub ..mu../) and thick walls (5 to 20/sub ..mu../) that contain various fill gases, such as Ar, Kr, Xe, Br, D, H/sub 2/, DT, He, N/sub 2/, Ne, CO/sub 2/, etc., in the interior thereof, can be produced by the diffusion of the fill gas or gases into the microsphere during the formation thereof from a liquid droplet of glass-form-forming solution. This is accomplished by filling at least a portion of the multiple-zone drop-furnace used in producing hollow microspheres with the gas or gases of interest, and then taking advantage of the high rate of gaseous diffusion of the fill gas through the wall of the gel membrane before it transforms into a glass microsphere as it is processed in the multiple-zone furnace.

  14. Preparation of small bio-compatible microspheres

    NASA Technical Reports Server (NTRS)

    Rembaum, Alan (Inventor); Yen, Shiao-Ping S. (Inventor); Dreyer, William J. (Inventor)

    1979-01-01

    Small, round, bio-compatible microspheres capable of covalently bonding proteins and having a uniform diameter below about 3500 A are prepared by substantially instantaneously initiating polymerization of an aqueous emulsion containing no more than 35% total monomer including an acrylic monomer substituted with a covalently bondable group such a hydroxyl, amino or carboxyl and a minor amount of a cross-linking agent.

  15. Gastrointestinal involvement in systemic sclerosis.

    PubMed

    Savarino, Edoardo; Furnari, Manuele; de Bortoli, Nicola; Martinucci, Irene; Bodini, Giorgia; Ghio, Massimo; Savarino, Vincenzo

    2014-10-01

    Systemic sclerosis is an autoimmune chronic disease characterised by microvascular, muscular and immunologic abnormalities that lead to progressive and systemic deposition of connective tissue in the skin and internal organs. The gastrointestinal tract is often overlooked by physicians but it is the most affected organ after the skin, from the mouth to the anus. Indeed, 80% of SSc patients may present with gastrointestinal involvement. Gastrointestinal manifestations range from bloating and heartburn to dysphagia and anorectal dysfunction to severe weight loss and malabsorption. However, the gastrointestinal involvement is rarely the direct cause of death, but has great impact on quality of life and leads to several comorbidities that subsequently affect patients' survival. Treatments, including nutritional support and prokinetics provide limited benefits and do not arrest the progressive course of the disease, but earlier detection of gastrointestinal involvement may reduce the risk of complications such as malnutrition. PMID:25179275

  16. Design and evaluation of surface and adjuvant modified PLGA microspheres for uptake by dendritic cells to improve vaccine responses.

    PubMed

    Salvador, Aiala; Sandgren, Kerrie J; Liang, Frank; Thompson, Elizabeth A; Koup, Richard A; Pedraz, José Luis; Hernandez, Rosa Maria; Loré, Karin; Igartua, Manoli

    2015-12-30

    Designing strategies for targeting antigens to dendritic cells is a major goal in vaccinology. Here, PLGA (poly lactic-co-glycolic acid) microspheres and with several surface modifications that affect to their uptake by human blood primary dendritic cells and monocytes have been evaluated. Higher uptake was found by all the cell types when cationic microspheres (PLGA modified with polyethylene imine) were used. These cationic particles were in vivo evaluated in mice. In addition, MPLA(1) or poly(I:C)(2) and α-GalCer(3) were also encapsulated to address their adjuvant effect. All the microspheres were able to produce humoral immune responses, albeit they were higher for cationic microspheres. Moreover, surface charge seemed to have a role on biasing the immune response; cationic microspheres induced higher IFN-γ levels, indicative of Th1 activation, while unmodified ones mainly triggered IL4 and IL17A release, showing Th2 activation. Thus, we have shown here the potential and versatility of these MS, which may be tailored to needs. PMID:26475970

  17. Shell-in-Shell TiO2 hollow microspheres and optimized application in light-trapping perovskite solar cells

    NASA Astrophysics Data System (ADS)

    Sun, Hongxia; Ruan, Peng; Bao, Zhongqiu; Chen, Lei; Zhou, Xingfu

    2015-02-01

    The shell-in-shell structured TiO2 hollow microspheres with enhanced light scattering ability were synthesized via a facile one step hydrothermal process. The diameter of the microsphere is about 1.5 μm, the core of the unique shell-in-shell structure is composed of TiO2 nanoparticles with a diameter of about 15 nm, while the shell is constructed with ∼50 nm TiO2 nanocubes. The hollow space between the outer shell and the inner shell is about 230 nm. The formation mechanism of the unique shell-in-shell structure is interpreted. The design and the optimized application of shell-in-shell structured TiO2 hollow microspheres in the light-trapping perovskite solar cells are also investigated. Owing to the light scattering properties of the shell-in-shell structure of the hollow microsphere, the optimized photoelectrode exhibits an enhanced photoelectric conversion efficiency of 4.29% using perovskite CH3NH3PbI3 as the sensitizer. The shell-in-shell hollow TiO2 microsphere shows a 21.2% increase in conversion efficiency when compared with P25 nanoparticels photoanode. The conversion efficiency enhancement is mainly attributed to the increase of short-current density induced by the light scattering effect.

  18. Surface properties of Toxoplasma gondii oocysts and surrogate microspheres.

    PubMed

    Shapiro, Karen; Largier, John; Mazet, Jonna A K; Bernt, William; Ell, John R; Melli, Ann C; Conrad, Patricia A

    2009-02-01

    The physical properties that govern the waterborne transmission of Toxoplasma gondii oocysts from land to sea were evaluated and compared to the properties of carboxylated microspheres, which could serve as surrogates for T. gondii oocysts in transport and water treatment studies. The electrophoretic mobilities of T. gondii oocysts, lightly carboxylated Dragon Green microspheres, and heavily carboxylated Glacial Blue microspheres were determined in ultrapure water, artificial freshwater with and without dissolved organic carbon, artificial estuarine water, and artificial seawater. The surface wettabilities of oocysts and microspheres were determined using a water contact angle approach. Toxoplasma gondii oocysts and microspheres were negatively charged in freshwater solutions, but their charges were neutralized in estuarine water and seawater. Oocysts, Glacial Blue microspheres, and unwashed Dragon Green microspheres had low contact angles, indicating that they were hydrophilic; however, once washed, Dragon Green microspheres became markedly hydrophobic. The hydrophilic nature and negative charge of T. gondii oocysts in freshwater could facilitate widespread contamination of waterways. The loss of charge observed in saline waters may lead to flocculation and subsequent accumulation of T. gondii oocysts in locations where freshwater and marine water mix, indicating a high risk of exposure for humans and wildlife in estuarine habitats with this zoonotic pathogen. While microspheres did not have surface properties identical to those of T. gondii, similar properties shared between each microsphere type and oocysts suggest that their joint application in transport and fate studies could provide a range of transport potentials in which oocysts are likely to behave. PMID:19060174

  19. PLGA/alginate composite microspheres for hydrophilic protein delivery.

    PubMed

    Zhai, Peng; Chen, X B; Schreyer, David J

    2015-11-01

    Poly(lactic-co-glycolic acid) (PLGA) microspheres and PLGA/alginate composite microspheres were prepared by a novel double emulsion and solvent evaporation technique and loaded with bovine serum albumin (BSA) or rabbit anti-laminin antibody protein. The addition of alginate and the use of a surfactant during microsphere preparation increased the encapsulation efficiency and reduced the initial burst release of hydrophilic BSA. Confocal laser scanning microcopy (CLSM) of BSA-loaded PLGA/alginate composite microspheres showed that PLGA, alginate, and BSA were distributed throughout the depths of microspheres; no core/shell structure was observed. Scanning electron microscopy revealed that PLGA microspheres erode and degrade more quickly than PLGA/alginate composite microspheres. When loaded with anti-laminin antibody, the function of released antibody was well preserved in both PLGA and PLGA/alginate composite microspheres. The biocompatibility of PLGA and PLGA/alginate microspheres were examined using four types of cultured cell lines, representing different tissue types. Cell survival was variably affected by the inclusion of alginate in composite microspheres, possibly due to the sensitivity of different cell types to excess calcium that may be released from the calcium cross-linked alginate. PMID:26249587

  20. Gastrointestinal hormones regulating appetite.

    PubMed

    Chaudhri, Owais; Small, Caroline; Bloom, Steve

    2006-07-29

    The role of gastrointestinal hormones in the regulation of appetite is reviewed. The gastrointestinal tract is the largest endocrine organ in the body. Gut hormones function to optimize the process of digestion and absorption of nutrients by the gut. In this capacity, their local effects on gastrointestinal motility and secretion have been well characterized. By altering the rate at which nutrients are delivered to compartments of the alimentary canal, the control of food intake arguably constitutes another point at which intervention may promote efficient digestion and nutrient uptake. In recent decades, gut hormones have come to occupy a central place in the complex neuroendocrine interactions that underlie the regulation of energy balance. Many gut peptides have been shown to influence energy intake. The most well studied in this regard are cholecystokinin (CCK), pancreatic polypeptide, peptide YY, glucagon-like peptide-1 (GLP-1), oxyntomodulin and ghrelin. With the exception of ghrelin, these hormones act to increase satiety and decrease food intake. The mechanisms by which gut hormones modify feeding are the subject of ongoing investigation. Local effects such as the inhibition of gastric emptying might contribute to the decrease in energy intake. Activation of mechanoreceptors as a result of gastric distension may inhibit further food intake via neural reflex arcs. Circulating gut hormones have also been shown to act directly on neurons in hypothalamic and brainstem centres of appetite control. The median eminence and area postrema are characterized by a deficiency of the blood-brain barrier. Some investigators argue that this renders neighbouring structures, such as the arcuate nucleus of the hypothalamus and the nucleus of the tractus solitarius in the brainstem, susceptible to influence by circulating factors. Extensive reciprocal connections exist between these areas and the hypothalamic paraventricular nucleus and other energy-regulating centres of the

  1. In vitro evaluation of biodegradable microspheres with surface-bound ligands.

    PubMed

    Keegan, Mark E; Royce, Sara M; Fahmy, Tarek; Saltzman, W Mark

    2006-02-21

    Protein ligands were conjugated to the surface of biodegradable microspheres. These microsphere-ligand conjugates were then used in two in vitro model systems to evaluate the effect of conjugated ligands on microsphere behavior. Microsphere retention in agarose columns was increased by ligands on the microsphere surface specific for receptors on the agarose matrix. In another experiment, conjugating the lectin Ulex europaeus agglutinin 1 to the microsphere surface increased microsphere adhesion to Caco-2 monolayers compared to control microspheres. This increase in microsphere adhesion was negated by co-administration of l-fucose, indicating that the increase in adhesion is due to specific interaction of the ligand with carbohydrate receptors on the cell surface. These results demonstrate that the ligands conjugated to the microspheres maintain their receptor binding activity and are present on the microsphere surface at a density sufficient to target the microspheres to both monolayers and three-dimensional matrices bearing complementary receptors. PMID:16386325

  2. Use of biodegradable PLGA microspheres as a slow release delivery system for the Boophilus microplus synthetic vaccine SBm7462.

    PubMed

    Sales-Junior, P A; Guzman, F; Vargas, M I; Sossai, S; Patarroyo V, A M; González, C Z L; Patarroyo, J H

    2005-09-15

    The synthetic anti-Boophilus microplus vaccine SBm7462 derived from the tick intestinal protein, Bm86, induced a protective immune response when emulsified in saponin and used in cattle. Using a mice model, and with the objective of improving the vaccine by continual peptide release, it was encapsulated in PLGA 50:50 microspheres and inoculated in BALB/c mice to assess the immunological response by detection of anti-peptide IgGs. Comparative studies were made with the peptide emulsified in saponin and with another synthetic vaccine, and the microsphere/peptide was characterized for efficiency of encapsulation, in vitro release profile, morphology, size, peptide integrity after encapsulation and stability in different pHs. The findings showed that saponin enhances a better immune response from SBm7462 and that the PLGA 50:50 microspheres are suitable for use with this peptide. PMID:16002149

  3. Ibuprofen microencapsulation within acrylamide-grafted chitosan and methylcellulose interpenetrating polymer network microspheres: Synthesis, characterization, and release studies.

    PubMed

    Bulut, Emine

    2016-06-01

    This study deals with the development of interpenetrating polymer network (IPN) microspheres of acrylamide (AAm) grafted onto a chitosan (CS) backbone and methylcellulose (MC). Chitosan-graft-polyacrylamide (CS-g-PAAm) was synthesized by cerium (IV) ammonium nitrate-induced free radical graft polymerization. The grafting percentage was found to be 50.58%. The synthesized graft copolymer and MC were used to prepare microspheres by the water-in-oil (w/o) emulsion-crosslinking method, and crosslinked with glutaraldehyde (GA) as drug delivery matrices of ibuprofen (IBU). The release of IBU from microspheres decreased when the amount of CS-g-PAAm in the polymer matrix and amount of crosslinker added were increased, while it increased with the increase of the IBU/polymer ratio. PMID:25749277

  4. Active self-healing encapsulation of vaccine antigens in PLGA microspheres

    PubMed Central

    Desai, Kashappa-Goud H.; Schwendeman, Steven P.

    2013-01-01

    Herein, we describe the detailed development of a simple and effective method to microencapsulate vaccine antigens in poly(lactic-co-glycolic acid) (PLGA) by simple mixing of preformed active self-microencapsulating (SM) PLGA microspheres in a low concentration aqueous antigen solution at modest temperature (10-38 °C). Co-encapsulating protein-sorbing vaccine adjuvants and polymer plasticizers were used to “actively” load the protein in the polymer pores and facilitate polymer self-healing at temperature > hydrated polymer glass transition temperature, respectively. The microsphere formulation parameters and loading conditions to provide optimal active self-healing microencapsulation of vaccine antigen in PLGA was investigated. Active self-healing encapsulation of two vaccine antigens, ovalbumin and tetanus toxoid (TT), in PLGA microspheres was adjusted by preparing blank microspheres containing different vaccine adjuvant (aluminum hydroxide (Al(OH)3) or calcium phosphate). Active loading of vaccine antigen in Al(OH)3-PLGA microspheres was found to: a) increase proportionally with an increasing loading of Al(OH)3 (0.88-3 wt%) and addition of porosigen, b) decrease when the inner Al(OH)3/trehalose phase to 1 mL outer oil phase and size of microspheres was respectively > 0.2 mL and 63 μm, and c) change negligibly by PLGA concentration and initial incubation (loading) temperature. Encapsulation of protein sorbing Al(OH)3 in PLGA microspheres resulted in suppression of self-healing of PLGA pores, which was then overcome by improving polymer chain mobility, which in turn was accomplished by coincorporating hydrophobic plasticizers in PLGA. Active self-healing microencapsulation of manufacturing process-labile TT in PLGA was found to: a) obviate micronization- and organic solvent-induced TT degradation, b) improve antigen loading (1.4-1.8 wt% TT) and encapsulation efficiency (~ 97%), c) provide nearly homogeneous distribution and stabilization of antigen in polymer

  5. Active self-healing encapsulation of vaccine antigens in PLGA microspheres.

    PubMed

    Desai, Kashappa-Goud H; Schwendeman, Steven P

    2013-01-10

    Herein, we describe the detailed development of a simple and effective method to microencapsulate vaccine antigens in poly(lactic-co-glycolic acid) (PLGA) by simple mixing of preformed active self-microencapsulating (SM) PLGA microspheres in a low concentration aqueous antigen solution at modest temperature (10-38 °C). Co-encapsulating protein-sorbing vaccine adjuvants and polymer plasticizers were used to "actively" load the protein in the polymer pores and facilitate polymer self-healing at a temperature>the hydrated polymer glass transition temperature, respectively. The microsphere formulation parameters and loading conditions to provide optimal active self-healing microencapsulation of vaccine antigens in PLGA was investigated. Active self-healing encapsulation of two antigens, ovalbumin and tetanus toxoid (TT), in PLGA microspheres was adjusted by preparing blank microspheres containing different vaccine adjuvants (aluminum hydroxide (Al(OH)₃) or calcium phosphate). Active loading of vaccine antigen in Al(OH)₃-PLGA microspheres was found to: a) increase with an increasing loading of Al(OH)₃ (0.88-3 wt.%) and addition of porosigen, b) decrease when the inner Al(OH)₃/trehalose phase to 1 mL outer oil phase and size of microspheres was respectively >0.2 mL and 63 μm, and c) change negligibly by PLGA concentration and initial incubation (loading) temperature. Encapsulation of protein sorbing Al(OH)₃ in PLGA microspheres resulted in suppression of self-healing of PLGA pores, which was then overcome by improving polymer chain mobility, which in turn was accomplished by coincorporating hydrophobic plasticizers in PLGA. Active self-healing microencapsulation of manufacturing process-labile TT in PLGA was found to: a) obviate micronization- and organic solvent-induced TT degradation, b) improve antigen loading (1.4-1.8 wt.% TT) and encapsulation efficiency (~97%), c) provide nearly homogeneous distribution and stabilization of antigen in polymer, and d

  6. Polymeric Microspheres as Protein Transduction Reagents*

    PubMed Central

    Nagel, David; Behrendt, Jonathan M.; Chimonides, Gwen F.; Torr, Elizabeth E.; Devitt, Andrew; Sutherland, Andrew J.; Hine, Anna V.

    2014-01-01

    Discovering the function of an unknown protein, particularly one with neither structural nor functional correlates, is a daunting task. Interaction analyses determine binding partners, whereas DNA transfection, either transient or stable, leads to intracellular expression, though not necessarily at physiologically relevant levels. In theory, direct intracellular protein delivery (protein transduction) provides a conceptually simpler alternative, but in practice the approach is problematic. Domains such as HIV TAT protein are valuable, but their effectiveness is protein specific. Similarly, the delivery of intact proteins via endocytic pathways (e.g. using liposomes) is problematic for functional analysis because of the potential for protein degradation in the endosomes/lysosomes. Consequently, recent reports that microspheres can deliver bio-cargoes into cells via a non-endocytic, energy-independent pathway offer an exciting and promising alternative for in vitro delivery of functional protein. In order for such promise to be fully exploited, microspheres are required that (i) are stably linked to proteins, (ii) can deliver those proteins with good efficiency, (iii) release functional protein once inside the cells, and (iv) permit concomitant tracking. Herein, we report the application of microspheres to successfully address all of these criteria simultaneously, for the first time. After cellular uptake, protein release was autocatalyzed by the reducing cytoplasmic environment. Outside of cells, the covalent microsphere–protein linkage was stable for ≥90 h at 37 °C. Using conservative methods of estimation, 74.3% ± 5.6% of cells were shown to take up these microspheres after 24 h of incubation, with the whole process of delivery and intracellular protein release occurring within 36 h. Intended for in vitro functional protein research, this approach will enable study of the consequences of protein delivery at physiologically relevant levels, without recourse

  7. Approaches to gastrointestinal cytoprotection: from isolated cells, via animal experiments to healthy human subjects and patients with different gastrointestinal disorders.

    PubMed

    Mózsik, Gyula; Szabó, Imre L; Czimmer, József

    2011-01-01

    Our clinical observations proved that the the duodenal ulcer in patients healed without any inhibition of gastric acid secretion (1965), and the healing rates of atropine vs cimetidine vs Carbenoxolone were equal and superior to that of placebo in randomized, prospective and multiclinical study of DU patients (1978). The phenomenon of gastric cytoprotection was defined by André Robert in rats (1979). The essential point of this phenomenon is that the prostaglandins prevent the chemical-induced gastric mucosal damage without affecting gastric acid secretion, this being originally suggested as a reaction specific to prostaglandins. Since then gastrointestinal cytoprotection has been shown with various agents (anticholinergic agents, H(2)RA, growth factors, body protecting compound, BPC) and retinoids in animals; the latter differing from the actions of vitamin A. In examining the various components of gastrointestinal cytoprotection , different studies have performed in isolated cells, stable cell lines, animal experiments, healthy human subjects, in patients chronic gastric and duodenal ulcers, and with different gastrointestinal disorders. Our attention has focused on the effects of cytoprotective agents on cellular viability, mitochondrial and DNA damage, oxygen free radicals, natural antioxidant systems, mucosal biochemistry, vascular events, gastrointestinal mucosal protection as well as in their prevention of different human diseases. This paper gives an overview on the different approaches for the exploring gastrointestinal cytoprotection (at the level of isolated cells, animal experiments, healthy human beings and patients with different gastrointestinal disorders). It has been indicated that the gastric cytoprotection exists in animals, human healthy subjects, patients with different gastrointestinal disorders. The our human observation in patients with duodenal ulcer healed without any changes of gastric acid secretion, there were no significant

  8. Autologous gastrointestinal reconstruction.

    PubMed

    Bianchi, A

    1995-02-01

    The patient with short bowel syndrome is essentially unable to absorb sufficient nutrients. This is caused by either short mucosal contact time, insufficient mucosal surface area (enterocyte mass), or a combination of the two. Management consists primarily in sustaining health and growth by intravenous nutrition and in enhancing the natural intestinal adaptation response. Surgery in the form of autologous gastrointestinal reconstruction (AGIR) is designed to redistribute the patient's own residual absorptive bowel to enhance adaptation and, possibly, to increase the absorptive mucosal surface by neomucosal growth. The alternative and ultimate fallback procedure in the management of intestinal failure is bowel transplantation, with its associated serious immunosuppression-related complications. Imaginative AGIR techniques provide new hope for the future. PMID:7728509

  9. Obesity and Gastrointestinal Diseases

    PubMed Central

    Fujimoto, Ai; Hoteya, Shu; Iizuka, Toshiro; Ogawa, Osamu; Mitani, Toshifumi; Kuroki, Yuichiro; Matsui, Akira; Nakamura, Masanori; Kikuchi, Daisuke; Yamashita, Satoshi; Furuhata, Tsukasa; Yamada, Akihiro; Nishida, Noriko; Arase, Koji; Hashimoto, Mitsuyo; Igarashi, Yoshinori; Kaise, Mitsuru

    2013-01-01

    The prevalence of obesity in the Japanese population has been increasing dramatically in step with the Westernization of lifestyles and food ways. Our study demonstrated significant associations between obesity and a number of gastrointestinal disorders in a large sample population in Japan. We demonstrated that reflux esophagitis and hiatal hernia were strongly related to obesity (BMI > 25) in the Japanese. In particular, obesity with young male was a high risk for these diseases. On the other hand, it has been reported that obesity is also associated with Barrett's esophagus and colorectal adenoma; however, obesity was not a risk factor for these diseases in our study. The difference of ethnicity of our subjects may partly explain why we found no data to implicate obesity as a risk factor for Barrett's esophagus. Arterial sclerosis associated with advanced age and hyperglycemia was accompanied by an increased risk of colorectal adenoma. PMID:23781242

  10. Obesity and gastrointestinal diseases.

    PubMed

    Fujimoto, Ai; Hoteya, Shu; Iizuka, Toshiro; Ogawa, Osamu; Mitani, Toshifumi; Kuroki, Yuichiro; Matsui, Akira; Nakamura, Masanori; Kikuchi, Daisuke; Yamashita, Satoshi; Furuhata, Tsukasa; Yamada, Akihiro; Nishida, Noriko; Arase, Koji; Hashimoto, Mitsuyo; Igarashi, Yoshinori; Kaise, Mitsuru

    2013-01-01

    The prevalence of obesity in the Japanese population has been increasing dramatically in step with the Westernization of lifestyles and food ways. Our study demonstrated significant associations between obesity and a number of gastrointestinal disorders in a large sample population in Japan. We demonstrated that reflux esophagitis and hiatal hernia were strongly related to obesity (BMI > 25) in the Japanese. In particular, obesity with young male was a high risk for these diseases. On the other hand, it has been reported that obesity is also associated with Barrett's esophagus and colorectal adenoma; however, obesity was not a risk factor for these diseases in our study. The difference of ethnicity of our subjects may partly explain why we found no data to implicate obesity as a risk factor for Barrett's esophagus. Arterial sclerosis associated with advanced age and hyperglycemia was accompanied by an increased risk of colorectal adenoma. PMID:23781242

  11. [Obesity and gastrointestinal motility].

    PubMed

    Lee, Joon Seong

    2006-08-01

    Gastrointestinal (GI) motility has a crucial role in the food consumption, digestion and absorption, and also controls the appetite and satiety. In obese patients, various alterations of GI motility have been investigated. The prevalence of GERD and esophageal motor disorders in obese patients are higher than those of general population. Gastric emptying of solid food is generally accelerated and fasting gastric volume especially in distal stomach is larger in obese patients without change in accommodation. Contractile activity of small intestine in fasting period is more prominent, but orocecal transit is delayed. Autonomic dysfunction is frequently demonstrated in obese patients. These findings correspond with increased appetite and delayed satiety in obese patients, but causes or results have not been confirmed. Therapeutic interventions of these altered GI motility have been developed using botulinum toxin, gastric electrical stimulation in obese patients. Novel agents targeted for GI hormone modulation (such as ghrelin and leptin) need to be developed in the near future. PMID:16929152

  12. Ketoprofen-poly(D,L-lactic-co-glycolic acid) microspheres: influence of manufacturing parameters and type of polymer on the release characteristics.

    PubMed

    Gabor, F; Ertl, B; Wirth, M; Mallinger, R

    1999-01-01

    The effect of manufacturing parameters on the size and drug-loading of ketoprofen-containing biodegradable and biocompatible poly(DL-lactic-co-glycolic acid) (PLGA) microspheres prepared by the solvent evaporation method was investigated. For both drug-free and drug-loaded microspheres, smaller microspheres with a narrower size distribution were obtained when the stirring rate or the volume of the organic phase was increased. Incorporation of ketoprofen was found to increase with increasing volume of the organic phase and decreasing pH of the aqueous phase, but was independent of the acidity and the inherent viscosity of the PLGA used. The biphasic release profile of ketoprofen from the microspheres was dependent on the type of PLGA as well as the size and drug-loading, two parameters governed by the manufacturing process. The first burst effect was found to increase with the drug content, reduction of size of the microspheres and increasing inherent viscosity of the matrix, whereas acidity of the PLGA had no effect on the release of this acidic drug. A vigorous first burst effect was associated with reduced sustained delivery of ketoprofen, the rate of the delayed release phase being dependent on the inherent viscosity of the matrix, the size, the payload and the pH during preparation of the microspheres. Thus, by selection of the manufacturing parameters and the type of PLGA, it is possible to design a controlled drug delivery system for the prolonged release of ketoprofen, improving therapy by possible reduction of time intervals between peroral administration and reduction of local gastrointestinal side effects. PMID:9972498

  13. The structural basis for the prevention of nonsteroidal antiinflammatory drug-induced gastrointestinal tract damage by the C-lobe of bovine colostrum lactoferrin.

    PubMed

    Mir, Rafia; Singh, Nagendra; Vikram, Gopalakrishnapillai; Kumar, Ramasamy Prem; Sinha, Mau; Bhushan, Asha; Kaur, Punit; Srinivasan, Alagiri; Sharma, Sujata; Singh, Tej P

    2009-12-16

    Nonsteroidal antiinflammatory drugs (NSAIDs), due to their good efficacy in the treatment of pain, inflammation, and fever, are among the most prescribed class of medicines in the world. The main drawback of NSAIDs is that they induce gastric complications such as peptic ulceration and injury to the intestine. Four NSAIDs, indomethacin, diclofenac, aspirin, and ibuprofen were selected to induce gastropathy in mouse models. It was found that the addition of C-terminal half of bovine lactoferrin (C-lobe) reversed the NSAID-induced injuries to the extent of 47-70% whereas the coadministration of C-lobe prevented it significantly. The C-lobe was prepared proteolytically using serine proteases. The binding studies of C-lobe with NSAIDs showed that these compounds bind to C-lobe with affinities ranging from 2.6 to 4.8 x 10(-4) M. The complexes of C-lobe were prepared with the above four NSAIDs. All four complexes were crystallized and their detailed three-dimensional structures were determined using x-ray crystallographic method. The structures showed that all the four NSAID molecules bound to C-lobe at the newly identified ligand binding site in C-lobe that is formed involving two alpha-helices, alpha10 and alpha11. The ligand binding site is separated from the well known iron binding site by the longest and the most stable beta-strand, betaj, in the structure. Similar results were also obtained with the full length lactoferrin molecule. This novel, to our knowledge, binding site in C-lobe of lactoferrin shows a good complementarity for the acidic and lipophilic compounds such as NSAIDs. We believe this indicates that C-lobe of lactoferrin can be exploited for the prevention of NSAID-induced gastropathy. PMID:20006955

  14. Disorders of gastrointestinal hypomotility.

    PubMed

    Bielefeldt, Klaus; Tuteja, Ashok; Nusrat, Salman

    2016-01-01

    Ingestion and digestion of food as well as expulsion of residual material from our gastrointestinal tract requires normal propulsive, i.e. motor, function. Hypomotility refers to inherited or acquired changes that come with decreased contractile forces or slower transit. It not only often causes symptoms but also may compromise nutritional status or lead to other complications. While severe forms, such as pseudo-obstruction or ileus, may have a tremendous functional impact, the less severe forms of hypomotility may well be more relevant, as they contribute to common disorders, such as functional dyspepsia, gastroparesis, chronic constipation, and irritable bowel syndrome (IBS). Clinical testing can identify changes in contractile activity, defined by lower amplitudes or abnormal patterns, and the related effects on transit. However, such biomarkers show a limited correlation with overall symptom severity as experienced by patients. Similarly, targeting hypomotility with pharmacological interventions often alters gut motor function but does not consistently improve symptoms. Novel diagnostic approaches may change this apparent paradox and enable us to obtain more comprehensive information by integrating data on electrical activity, mechanical forces, patterns, wall stiffness, and motions with information of the flow of luminal contents. New drugs with more selective effects or more specific delivery may improve benefits and limit adverse effects. Lastly, the complex regulation of gastrointestinal motility involves the brain-gut axis as a reciprocal pathway for afferent and efferent signaling. Considering the role of visceral input in emotion and the effects of emotion on visceral activity, understanding and managing hypomotility disorders requires an integrative approach based on the mind-body continuum or biopsychosocial model of diseases. PMID:27583135

  15. Disorders of gastrointestinal hypomotility

    PubMed Central

    Bielefeldt, Klaus; Tuteja, Ashok; Nusrat, Salman

    2016-01-01

    Ingestion and digestion of food as well as expulsion of residual material from our gastrointestinal tract requires normal propulsive, i.e. motor, function. Hypomotility refers to inherited or acquired changes that come with decreased contractile forces or slower transit. It not only often causes symptoms but also may compromise nutritional status or lead to other complications. While severe forms, such as pseudo-obstruction or ileus, may have a tremendous functional impact, the less severe forms of hypomotility may well be more relevant, as they contribute to common disorders, such as functional dyspepsia, gastroparesis, chronic constipation, and irritable bowel syndrome (IBS). Clinical testing can identify changes in contractile activity, defined by lower amplitudes or abnormal patterns, and the related effects on transit. However, such biomarkers show a limited correlation with overall symptom severity as experienced by patients. Similarly, targeting hypomotility with pharmacological interventions often alters gut motor function but does not consistently improve symptoms. Novel diagnostic approaches may change this apparent paradox and enable us to obtain more comprehensive information by integrating data on electrical activity, mechanical forces, patterns, wall stiffness, and motions with information of the flow of luminal contents. New drugs with more selective effects or more specific delivery may improve benefits and limit adverse effects. Lastly, the complex regulation of gastrointestinal motility involves the brain-gut axis as a reciprocal pathway for afferent and efferent signaling. Considering the role of visceral input in emotion and the effects of emotion on visceral activity, understanding and managing hypomotility disorders requires an integrative approach based on the mind-body continuum or biopsychosocial model of diseases. PMID:27583135

  16. Effect of dopamine-related drugs on duodenal ulcer induced by cysteamine or propionitrile: prevention and aggravation may not be mediated by gastrointestinal secretory changes in the rat

    SciTech Connect

    Gallagher, G.; Brown, A.; Szabo, S.

    1987-03-01

    Dose- and time-response studies have been performed with dopamine agonists and antagonists using the cysteamine and propionitrile duodenal ulcer models in the rat. The experiments demonstrate that the chemically induced duodenal ulcer is prevented by bromocriptine, lergotrile and reduced by apomorphine or L-dopa. Aggravation of cysteamine-induced duodenal ulcer was seen especially after (-)-butaclamol, (-)-sulpiride, haloperidol and, less effectively, after other dopaminergic antagonists. The duodenal antiulcerogenic action of dopamine agonists was more prominent after chronic administration than after a single dose, whereas the opposite was found concerning the proulcerogenic effect of dopamine antagonists. In the chronic gastric fistula rat, both the antiulcerogens bromocriptine or lergotrile and the proulcerogens haloperidol, pimozide or (-)-N-(2-chlorethyl)-norapomorphine decreased the cysteamine- or propionitrile-induced gastric secretion. No correlation was apparent between the influence of these drugs on duodenal ulcer development and gastric and duodenal (pancreatic/biliary) secretions. In the chronic duodenal fistula rat, decreased acid content was measured in the proximal duodenum after haloperidol, and diminished duodenal pepsin exposure was recorded after bromocriptine. Furthermore, the aggravation by dopamine antagonists of experimental duodenal ulcer probably involves a peripheral component. The site of dopamine receptors and physiologic effects which modulate experimental duodenal ulcer remain to be identified, but their elucidation may prove to be an important element in the pathogenesis and treatment of duodenal ulcer.

  17. Nanoporous Monolithic Microsphere Arrays Have Anti-Adhesive Properties Independent of Humidity

    NASA Astrophysics Data System (ADS)

    Eichler-Volf, Anna; Xue, Longjian; Kovalev, Alexander; Gorb, Elena; Gorb, Stanislav; Steinhart, Martin

    2016-05-01

    Bioinspired artificial surfaces with tailored adhesive properties have attracted significant interest. While fibrillar adhesive pads mimicking gecko feet are optimized for strong reversible adhesion, monolithic microsphere arrays mimicking the slippery zone of the pitchers of carnivorous plants of the genus Nepenthes show anti-adhesive properties even against tacky counterpart surfaces. In contrast to the influence of topography, the influence of relative humidity (RH) on adhesion has been widely neglected. Some previous works deal with the influence of RH on the adhesive performance of fibrillar adhesive pads. Commonly, humidity-induced softening of the fibrils enhances adhesion. However, little is known on the influence of RH on solid anti-adhesive surfaces. We prepared polymeric nanoporous monolithic microsphere arrays (NMMAs) with microsphere diameters of a few 10 {\\mu}m to test their anti-adhesive properties at RHs of 2 % and 90 %. Despite the presence of continuous nanopore systems through which the inner nanopore walls were accessible to humid air, the topography-induced anti-adhesive properties of NMMAs on tacky counterpart surfaces were retained even at RH = 90 %. This RH-independent robustness of the anti-adhesive properties of NMMAs significantly contrasts the adhesion enhancement by humidity-induced softening on nanoporous fibrillar adhesive pads made of the same material.

  18. Casimir microsphere diclusters and three-body effects in fluids

    SciTech Connect

    Varela, Jaime; McCauley, Alexander P.; Rodriguez, Alejandro W.; Johnson, Steven G.

    2011-04-15

    Our previous paper [Phys. Rev. Lett. 104, 060401 (2010)] predicted that Casimir forces induced by the material-dispersion properties of certain dielectrics can give rise to stable configurations of objects. This phenomenon was illustrated via a dicluster configuration of nontouching objects consisting of two spheres immersed in a fluid and suspended against gravity above a plate. Here, we examine these predictions from the perspective of a practical experiment and consider the influence of nonadditive, three-body, and nonzero-temperature effects on the stability of the two spheres. We conclude that the presence of Brownian motion reduces the set of experimentally realizable silicon-teflon spherical diclusters to those consisting of layered microspheres, such as the hollow core (spherical shells) considered here.

  19. Optically Levitated Microspheres as a Probe for New Interactions

    NASA Astrophysics Data System (ADS)

    Rider, Alexander; Moore, David; Blakemore, Charles; Lu, Marie; Gratta, Giorgio

    2016-03-01

    We are developing novel techniques to probe new interactions at micron distances using optically levitated dielectric microspheres. Levitated microspheres are an ideal probe for short-range interactions because they are suspended using the radiation pressure at the focus of a laser beam, which means that the microspheres can be precisely manipulated and isolated from the surrounding environment at high vacuum. We have performed a search for unknown charged particles bound within the bulk of the microspheres. Currently, we are searching for the presence of a Chameleon field postulated to explain the presence of dark energy in the universe. In the future we plan to use optically levitated microspheres to search for micron length-scale gravity like interactions that could couple between a microsphere and another mass. We will present resent results from these experiments and plans for future searches for new interactions.

  20. Method of detecting luminescent target ions with modified magnetic microspheres

    DOEpatents

    Shkrob, Ilya A; Kaminski, Michael D

    2014-05-13

    This invention provides methods of using modified magnetic microspheres to extract target ions from a sample in order to detect their presence in a microfluidic environment. In one or more embodiments, the microspheres are modified with molecules on the surface that allow the target ions in the sample to form complexes with specific ligand molecules on the microsphere surface. In one or more embodiments, the microspheres are modified with molecules that sequester the target ions from the sample, but specific ligand molecules in solution subsequently re-extract the target ions from the microspheres into the solution, where the complexes form independent of the microsphere surface. Once the complexes form, they are exposed to an excitation wavelength light source suitable for exciting the target ion to emit a luminescent signal pattern. Detection of the luminescent signal pattern allows for determination of the presence of the target ions in the sample.

  1. Formulation and evaluation of Bacillus coagulans-loaded hypromellose mucoadhesive microspheres.

    PubMed

    Alli, Sk Md Athar

    2011-01-01

    Development of a novel delivery system has been attempted to deliver viable probiotic cells into the gut for a prolonged period of time while maintaining high numbers of viable cells within the formulation throughout the shelf-life of the product and during the gastrointestinal transit. Core mucoadhesive microspheres of Bacillus coagulans were developed employing several grades of hypromellose, a mucoadhesive polymer, following coacervation and phase separation technique and were subsequently enteric-coated with hypromellose phthalate. Microspheres were evaluated for percent yield; entrapment efficiency; in vitro swelling; surface morphology; particle size, size distribution, and zeta potential; flow property, mucoadhesion property by the ex vivo mucoadhesive strength test and the in vitro wash off test; in vitro release profile and release kinetic; in vivo probiotic activity; and stability. The values for the kinetic constant and regression coefficient of model-dependent approaches and the difference factor (f(1)), the similarity factor (f(2)), and the Rescigno index (ξ(1) and ξ(2)) of model independent approaches were determined for comparing in vitro dissolution profiles. Freeze dried B. coagulans cells were successfully formulated as enteric-coated mucoadhesive microspheres with satisfactory physical structure and yield. The viability of B. coagulans was maintained in the simulated gastric conditions and during processing; in simulated intestinal conditions exhibiting mucoadhesion, and controlling and extending the viable cell release following zero-order; and was satisfactorily stable at room temperature. Test results depict statistically significant effects of the hypromellose grade and their concentration on the performance and release profile of formulations. PMID:21674019

  2. Decreased plasma isoleucine concentrations after upper gastrointestinal haemorrhage in humans.

    PubMed Central

    Dejong, C H; Meijerink, W J; van Berlo, C L; Deutz, N E; Soeters, P B

    1996-01-01

    BACKGROUND: A decrease in arterial isoleucine values after intragastric blood administration in pigs has been observed. This contrasted with increased values of most other amino acids, ammonia, and urea. After an isonitrogenous control meal in these pigs all amino acids including isoleucine increased, and urea increased to a lesser extent, suggesting a relation between the arterial isoleucine decrease and uraemia after gastrointestinal haemorrhage. METHODS: To extend these findings to humans, plasma amino acids were determined after gastrointestinal haemorrhage in patients with peptic ulcers (n = 9) or oesophageal varices induced by liver cirrhosis (n = 4) and compared with preoperative patients (n = 106). RESULTS: After gastrointestinal haemorrhage, isoleucine decreased in all patients by more than 60% and normalised within 48 hours. Most other amino acids increased and also normalised within 48 hours. Uraemia occurred in both groups, hyperammonaemia was seen in patients with liver cirrhosis. CONCLUSIONS: These results confirm previous findings in animals and healthy volunteers that plasma isoleucine decreases after simulated upper gastrointestinal haemorrhage. This supports the hypothesis that the absence of isoleucine in blood protein causes decreased plasma isoleucine values after gastrointestinal haemorrhage, and may be a contributory factor to uraemia and hyperammonaemia in patients with normal and impaired liver function, respectively. Intravenous isoleucine administration after gastrointestinal haemorrhage could be beneficial and will be the subject of further research. PMID:8881800

  3. Liquid-crystal tunable filter based on sapphire microspheres.

    PubMed

    Gilardi, Giovanni; Donisi, Domenico; Serpengüzel, Ali; Beccherelli, Romeo

    2009-11-01

    We design an integrated optoelectronic device based on the whispering-gallery modes of a sapphire microsphere integrated with a liquid-crystal tuning medium to produce a narrowband, electrically tunable, channel-dropping filter. The sapphire microsphere is glued over a diffused waveguide in a glass substrate. At the base of the microsphere, a small volume of liquid crystal is infiltrated. We numerically evaluate the performance of the device and demonstrate a voltage tuning of the narrowband resonances. PMID:19881558

  4. (D, L) polylactide microspheres as embolic agent. A preliminary study.

    PubMed

    Flandroy, P; Grandfils, C; Collignon, J; Thibaut, A; Nihant, N; Barbette, S; Jerome, R; Teyssie, P

    1990-01-01

    Owing to their shape, accurately calibrated microspheres appear to be very suitable material for distal embolization. Moreover, the biocompatible (D, L) polyactide (PLA) microspheres possess two other valuable advantages: easy adjustment of their biodegradation rate, and incorporation of chemotherapeutic agents during their production. The authors describe the preparation of these (D, L) PLA microspheres and their clinical applications as a preliminary step to arterial chemoembolization. PMID:2234391

  5. Beat frequency ultrasonic microsphere contrast agent detection system

    NASA Technical Reports Server (NTRS)

    Pretlow, III, Robert A. (Inventor); Yost, William T. (Inventor); Cantrell, Jr., John H. (Inventor)

    1997-01-01

    A system for and method of detecting and measuring concentrations of an ultrasonically-reflective microsphere contrast agent involving detecting non-linear sum and difference beat frequencies produced by the microspheres when two impinging signals with non-identical frequencies are combined by mixing. These beat frequencies can be used for a variety of applications such as detecting the presence of and measuring the flow rates of biological fluids and industrial liquids, including determining the concentration level of microspheres in the myocardium.

  6. Second order parametric processes in nonlinear silica microspheres.

    PubMed

    Xu, Yong; Han, Ming; Wang, Anbo; Liu, Zhiwen; Heflin, James R

    2008-04-25

    We analyze second order parametric processes in a silica microsphere coated with radially aligned nonlinear optical molecules. In a high-Q nonlinear microsphere, we discover that it is possible to achieve ultralow threshold parametric oscillation that obeys the rule of angular momentum conservation. Based on symmetry considerations, one can also implement parametric processes that naturally generate quantum entangled photon pairs. Practical issues regarding implementation of the nonlinear microsphere are also discussed. PMID:18518201

  7. A Radically New Method for Hydrogen Storage in Hollow Glass Microspheres

    SciTech Connect

    James E. Shelby; Matthew M. Hall; Fabienne C. Raszewski

    2007-08-31

    Photo-induced hydrogen diffusion has been applied to the problem of storage of high pressure hydrogen in hollow glass microspheres. Results of this study indicate that this phenomenon can be used to provide a high mass efficiency, safe, cheap, non-toxic method for storage of high pressure hydrogen. The photo-induced response is immediate upon exposure to infrared light for hollow glass microspheres doped with iron, nickel, or cobalt oxide, which is consistent with previous results for transition metal oxide-doped bulk glass samples. This effect is not observed for HGMS which do not contain these transition metal oxide, where the slight release of hydrogen observed occurs only by heating from absorption of the light. The initial rate of hydrogen release increases with increasing concentration of the metal oxide and with increasing hydrogen fill pressure within the microspheres. To date, hydrogen storage efficiencies of 2.2 wt% have been obtained, but results suggest that storage values can be increased to at least 6 wt%. Hydrogen losses over a 5 week period are minimal at room temperature in all compositions, with somewhat greater, but acceptable, losses at 50 C. Hollow glass microspheres have been produced from an alkali alkaline earth borosilicate glass containing either 1 or 5 wt% of the oxides of iron, nickel, and cobalt. Photo-driven gas diffusion has been demonstrated for these HGMS. Demonstration of photo-induced diffusion in these samples provides the first proof-of-concept for eventual applications of HGMS for large scale hydrogen storage.

  8. Low threshold lasing of bubble-containing glass microspheres by non-whispering gallery mode excitation over a wide wavelength range

    SciTech Connect

    Kumagai, Tsutaru Kishi, Tetsuo; Yano, Tetsuji

    2015-03-21

    Bubble-containing Nd{sup 3+}-doped tellurite glass microspheres were fabricated by localized laser heating technique to investigate their optical properties for use as microresonators. Fluorescence and excitation spectra measurements were performed by pumping with a tunable CW-Ti:Sapphire laser. The excitation spectra manifested several sharp peaks due to the conventional whispering gallery mode (WGM) when the pumping laser was irradiated to the edge part of the microsphere. However, when the excitation light was irradiated on the bubble position inside the microsphere, “non-WGM excitation” was induced, giving rise to numerous peaks at a broad wavelength range in the excitation spectra. Thus, efficient excitation was achieved over a wide wavelength range. Lasing threshold excited at the bubble position was much lower than that for the excitation at the edges of the microsphere. The lowest value of the laser threshold was 34 μW for a 4 μm sphere containing a 0.5 μm bubble. Efficiency of the excitation at the bubble position with broadband light was calculated to be 5 times higher than that for the edge of the microsphere. The bubble-containing microsphere enables efficient utilization of broadband light excitation from light-emitting diodes and solar light.

  9. Preparation of uniform magnetic recoverable catalyst microspheres with hierarchically mesoporous structure by using porous polymer microsphere template

    PubMed Central

    2014-01-01

    Merging nanoparticles with different functions into a single microsphere can exhibit profound impact on various applications. However, retaining the unique properties of each component after integration has proven to be a significant challenge. Our previous research demonstrated a facile method to incorporate magnetic nanoparticles into porous silica microspheres. Here, we report the fabrication of porous silica microspheres embedded with magnetic and gold nanoparticles as magnetic recoverable catalysts. The as-prepared multifunctional composite microspheres exhibit excellent magnetic and catalytic properties and a well-defined structure such as uniform size, high surface area, and large pore volume. As a result, the very little composite microspheres show high performance in catalytic reduction of 4-nitrophenol, special convenient magnetic separability, long life, and good reusability. The unique nanostructure makes the microspheres a novel stable and highly efficient catalyst system for various catalytic industry processes. PMID:24708885

  10. The xanthene dyes doped PMMA microspheres for optical sensor applications

    NASA Astrophysics Data System (ADS)

    Miluski, Piotr; Dorosz, Dominik; Kochanowicz, Marcin; Zmojda, Jacek; Dorosz, Jan

    2015-12-01

    The numerous applications of luminescent glass and polymeric microspheres are well known. The polymeric structures are popular as they assure good processability (solid and porous structures) and high doping level. The article presents the suspension polymerization process of polymeric (PMMA) microspheres doped by xanthene dyes: Fluorescein (Fl) and Rhodamine B (RhB). The bright luminescence at wavelengths 510nm 595nm respectively was recorded. The shape and dimension distributions of fabricated microspheres were optically determined. The article presents also potential applications of fabricated luminescent microspheres.

  11. Chitosan microspheres as a delivery system for nasal insufflation.

    PubMed

    Patil, Sanjay B; Sawant, Krutika K

    2011-06-01

    The aim of the present study was to develop and characterize chitosan mucoadhesive microspheres for nasal delivery. The microspheres were prepared by emulsification-crosslinking method and evaluated for morphology, particle size, swelling index, in vitro mucoadhesion and delivery properties from Miat(®) nasal insufflator. The results showed that the microspheres were spherical in shape with smooth surfaces. The particle size of microspheres was found to be dependent on the concentration of the chitosan. The mean particle size was significantly increased when high concentration of chitosan was used. Aqueous to oil phase ratio, stirring rate and dioctyl sodium sulfosuccinate (DOSS) concentration also influenced the particle size distribution of the microspheres. It was found that, as stirring rate was increased, the size of the microspheres was decreased. The volume of glutaraldehyde and crosslinking time had very slight effect on particle size distribution. The % equilibrium water uptake of the microspheres was ranged from 124% to 232% and the mucoadhesive strength from 70.64±2.14 to 86.32±3.96%. The results of powder delivery from the device showed that, almost entire amount was delivered after three puffs. The images of the delivery sequences of microsphere powder clouds demonstrated that microspheres were delivered forming an elongated puff. The core of the clouds was homogeneous which can be expected to provide effective distribution pattern. PMID:21320767

  12. Controlled Delivery of Gentamicin Using Poly(3-hydroxybutyrate) Microspheres

    PubMed Central

    Francis, Lydia; Meng, Decheng; Knowles, Jonathan; Keshavarz, Tajalli; Boccaccini, Aldo R.; Roy, Ipsita

    2011-01-01

    Poly(3-hydroxybutyrate), P(3HB), produced from Bacillus cereus SPV using a simple glucose feeding strategy was used to fabricate P(3HB) microspheres using a solid-in-oil-water (s/o/w) technique. For this study, several parameters such as polymer concentration, surfactant and stirring rates were varied in order to determine their effect on microsphere characteristics. The average size of the microspheres was in the range of 2 μm to 1.54 μm with specific surface areas varying between 9.60 m2/g and 6.05 m2/g. Low stirring speed of 300 rpm produced slightly larger microspheres when compared to the smaller microspheres produced when the stirring velocity was increased to 800 rpm. The surface morphology of the microspheres after solvent evaporation appeared smooth when observed under SEM. Gentamicin was encapsulated within these P(3HB) microspheres and the release kinetics from the microspheres exhibiting the highest encapsulation efficiency, which was 48%, was investigated. The in vitro release of gentamicin was bimodal, an initial burst release was observed followed by a diffusion mediated sustained release. Biodegradable P(3HB) microspheres developed in this research has shown high potential to be used in various biomedical applications. PMID:21845079

  13. Liquid phase coating to produce controlled-release alginate microspheres.

    PubMed

    Chan, Lai Wah; Liu, Xiaohua; Heng, Paul Wan Sia

    2005-12-01

    This study explored a liquid phase coating technique to produce polymethyl methacrylate (PMMA)-coated alginate microspheres. Alginate microspheres with a mean diameter of 85.6 microm were prepared using an emulsification method. The alginate microspheres, as cores, were then coated with different types of PMMA by a liquid phase coating technique. The release characteristics of these coated microspheres in simulated gastric (SGF) and intestinal (SIF) fluids and the influence of drug load on encapsulation efficiency were studied. The release of paracetamol, as a model hydrophilic drug, from the coated microspheres in SGF and SIF was greatly retarded. Release rates of Eudragit RS100-coated microspheres in SGF and SIF were similar as the rate-controlling polymer coat was insoluble in both media. Drug release from Eudragit S100-coated microspheres was more sustained in SGF than in SIF, due to the greater solubility of the coating polymer in media with pH greater than 7.0. The drug release rate was affected by the core:coat ratio. Drug release from the coated microspheres was best described by the Higuchi's square root model. The liquid phase coating technique developed offers an efficient method of coating small microspheres with markedly reduced drug loss and possible controlled drug release. PMID:16423760

  14. Stabilization of layer-by-layer engineered multilayered hollow microspheres.

    PubMed

    Liu, Peng

    2014-05-01

    Polymer multilayered hollow microspheres prepared by layer-by-layer (LbL) self-assembly attract more and more interest due to their unique application, especially as drug delivery system (DDS). Unfortunately, the multilayered hollow microspheres assembled via weak linkages could fuse and/or aggregate in high ionic strength media or strong acidic or basic media. This severely restricts the practical applications of the multilayered hollow microspheres as DDS in human physiological medium. In the present work, the progress in stabilization of the multilayered hollow microspheres is reviewed, with emphasis on the assembling process and their crosslinking mechanism. PMID:24321861

  15. Sleep Dysfunction and Gastrointestinal Diseases

    PubMed Central

    Khanijow, Vikesh; Prakash, Pia; Emsellem, Helene A.; Borum, Marie L.

    2015-01-01

    Sleep deprivation and impaired sleep quality have been associated with poor health outcomes. Many patients experience sleep disturbances, which can increase the risk of medical conditions such as hypertension, obesity, stroke, and heart disease as well as increase overall mortality. Recent studies have suggested that there is a strong association between sleep disturbances and gastrointestinal diseases. Proinflammatory cytokines, such as tumor necrosis factor, interleukin-1, and interleukin-6, have been associated with sleep dysfunction. Alterations in these cytokines have been seen in certain gastrointestinal diseases, such as gastroesophageal reflux disease, inflammatory bowel disease, liver disorders, and colorectal cancer. It is important for gastroenterologists to be aware of the relationship between sleep disorders and gastrointestinal illnesses to ensure good care for patients. This article reviews the current research on the interplay between sleep disorders, immune function, and gastrointestinal diseases. PMID:27134599

  16. Gastrointestinal hemorrhage: evaluation with MDCT.

    PubMed

    Soto, Jorge A; Park, Seong Ho; Fletcher, Joel G; Fidler, Jeff L

    2015-06-01

    Gastrointestinal (GI) bleeding is a common medical problem, with high associated morbidity and mortality. The clinical presentation of gastrointestinal hemorrhage varies with the location of the bleeding source, the intensity of the bleed, and the presence of comorbidities that affect the ability to tolerate blood loss. Conventional endoscopic examinations are usually the initial diagnostic tests in patients presenting with overt gastrointestinal hemorrhage. However, implementation of upper tract endoscopy and colonoscopy in the emergency setting can be challenging due to inconsistent availability of the service and difficulties in achieving adequate colonic cleansing in emergent situations. Thus, imaging tests are often relied upon to establish the location and the cause of bleeding, either for initial diagnosis or after non-revealing upper and lower tract endoscopies ("obscure" bleeding). This article discusses the imaging evaluation of patients with gastrointestinal bleeding and reviews the imaging appearance of the most common causes, taking into account the two most relevant clinical presentations: overt bleeding and obscure bleeding. PMID:25637128

  17. Epigenetic mechanisms and gastrointestinal development

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This review considers the hypothesis that nutrition during infancy affects developmental epigenetics in the gut, causing metabolic imprinting of gastrointestinal (GI) structure and function. Fundamentals of epigenetic gene regulation are reviewed, with an emphasis on the epigenetic mechanism of DNA ...

  18. Sleep Dysfunction and Gastrointestinal Diseases.

    PubMed

    Khanijow, Vikesh; Prakash, Pia; Emsellem, Helene A; Borum, Marie L; Doman, David B

    2015-12-01

    Sleep deprivation and impaired sleep quality have been associated with poor health outcomes. Many patients experience sleep disturbances, which can increase the risk of medical conditions such as hypertension, obesity, stroke, and heart disease as well as increase overall mortality. Recent studies have suggested that there is a strong association between sleep disturbances and gastrointestinal diseases. Proinflammatory cytokines, such as tumor necrosis factor, interleukin-1, and interleukin-6, have been associated with sleep dysfunction. Alterations in these cytokines have been seen in certain gastrointestinal diseases, such as gastroesophageal reflux disease, inflammatory bowel disease, liver disorders, and colorectal cancer. It is important for gastroenterologists to be aware of the relationship between sleep disorders and gastrointestinal illnesses to ensure good care for patients. This article reviews the current research on the interplay between sleep disorders, immune function, and gastrointestinal diseases. PMID:27134599

  19. Gastrointestinal Motility Disorders in Children

    PubMed Central

    Ambartsumyan, Lusine

    2014-01-01

    The most common and challenging gastrointestinal motility disorders in children include gastroesophageal reflux disease (GERD), esophageal achalasia, gastroparesis, chronic intestinal pseudo-obstruction, and constipation. GERD is the most common gastrointestinal motility disorder affecting children and is diagnosed clinically and treated primarily with acid secretion blockade. Esophageal achalasia, a less common disorder in the pediatric patient population, is characterized by dysphagia and treated with pneumatic balloon dilation and/or esophagomyotomy. Gastroparesis and chronic intestinal pseudo-obstruction are poorly characterized in children and are associated with significant morbidity. Constipation is among the most common complaints in children and is associated with significant morbidity as well as poor quality of life. Data on epidemiology and outcomes, clinical trials, and evaluation of new diagnostic techniques are needed to better diagnose and treat gastrointestinal motility disorders in children. We present a review of the conditions and challenges related to these common gastrointestinal motility disorders in children. PMID:24799835

  20. [Microbiological diagnosis of gastrointestinal infections].

    PubMed

    Vila, Jordi; Alvarez-Martínez, Miriam J; Buesa, Javier; Castillo, Javier

    2009-01-01

    Acute gastrointestinal tract infections are among the most common infectious diseases. In the present review, the different methods of diagnosing gastrointestinal infections caused by bacteria, viruses, and parasites are examined. Stool culture is the method of choice for diagnosing bacterial intestinal infections; however, infections caused by Clostridium difficile can be diagnosed by detection of toxins A and B in stools, and infections caused by diarrheagenic Escherichia coli by PCR detection of specific virulence factor genes harbored by several E. coli pathotypes. The techniques used to diagnose viral gastrointestinal infections include detection of viral antigens and nucleic acids. Finally, gastrointestinal infections caused by parasites can be diagnosed by testing for trophozoites and cysts of protozoa, or larvae and eggs of helminths in stools by direct microscopic examination, with concentration techniques, or by specific stains. PMID:19477556

  1. The effects of acute oral glutamine supplementation on exercise-induced gastrointestinal permeability and heat shock protein expression in peripheral blood mononuclear cells.

    PubMed

    Zuhl, Micah; Dokladny, Karol; Mermier, Christine; Schneider, Suzanne; Salgado, Roy; Moseley, Pope

    2015-01-01

    Chronic glutamine supplementation reduces exercise-induced intestinal permeability and inhibits the NF-κB pro-inflammatory pathway in human peripheral blood mononuclear cells. These effects were correlated with activation of HSP70. The purpose of this paper is to test if an acute dose of oral glutamine prior to exercise reduces intestinal permeability along with activation of the heat shock response leading to inhibition of pro-inflammatory markers. Physically active subjects (N = 7) completed baseline and exercise intestinal permeability tests, determined by the percent ratio of urinary lactulose (5 g) to rhamnose (2 g). Exercise included two 60-min treadmill runs at 70 % of VO2max at 30 °C after ingestion of glutamine (Gln) or placebo (Pla). Plasma levels of endotoxin and TNF-α, along with peripheral blood mononuclear cell (PBMC) protein expression of HSP70 and IκBα, were measured pre- and post-exercise and 2 and 4 h post-exercise. Permeability increased in the Pla trial compared to that at rest (0.06 ± 0.01 vs. 0.02 ± 0.018) and did not increase in the Gln trial. Plasma endotoxin was lower at the 4-h time point in the Gln vs. 4 h in the Pla (6.715 ± 0.046 pg/ml vs. 7.952 ± 1.11 pg/ml). TNF-α was lower 4 h post-exercise in the Gln vs. Pla (1.64 ± 0.09 pg/ml vs. 1.87 ± 0.12 pg/ml). PBMC expression of IkBα was higher 4 h post-exercise in the Gln vs. 4 h in the Pla (1.29 ± 0.43 vs. 0.8892 ± 0.040). HSP70 was higher pre-exercise and 2 h post-exercise in the Gln vs. Pla (1.35 ± 0.21 vs. 1.000 ± 0.000 and 1.65 ± 0.21 vs. 1.27 ± 0.40). Acute oral glutamine supplementation prevents an exercise-induced rise in intestinal permeability and suppresses NF-κB activation in peripheral blood mononuclear cells. PMID:25062931

  2. Epidemiology of gastrointestinal cancer.

    PubMed

    Selikoff, I J

    1974-12-01

    Some 99,000 new cases of cancer of the colon are expected next year, an incidence rate higher than that for both cancer of the lung and cancer of the breast. Evidence from geographic pathology suggests that some environmental factors play a strong role in its etiology. Data obtained in the 1959 survey of one million people by the American Cancer Society and followed since, has failed to show correlation with any of the large number of factors listed. It is suggested that the etiology is one of multiple factors. The synergistic effect of exposure to asbestos and cigarette smoking in the production of bronchogenic carcinoma is demonstrated by data on cohorts of insulation workers. There was also a modest increase in the number of deaths from gastrointestinal cancer in asbestos workers, but smoking did not seem to act in synergistic fashion at that site, except perhaps in the esophagus. Deaths from cancer occurred almost entirely after a period of 20 years or more from initial exposure. The death rate from cancer tended to increase with duration of exposure, but a distinct rise over the expected was seen in those who had been exposed less than one year to amosite dust. PMID:4470947

  3. Gastrointestinal perforation: ultrasonographic diagnosis

    PubMed Central

    2013-01-01

    Gastrointestinal tract perforations can occur for various causes such as peptic ulcer, inflammatory disease, blunt or penetrating trauma, iatrogenic factors, foreign body or a neoplasm that require an early recognition and, often, a surgical treatment. Ultrasonography could be useful as an initial diagnostic test to determine, in various cases the presence and, sometimes, the cause of the pneumoperitoneum. The main sonographic sign of perforation is free intraperitoneal air, resulting in an increased echogenicity of a peritoneal stripe associated with multiple reflection artifacts and characteristic comet-tail appearance. It is best detected using linear probes in the right upper quadrant between the anterior abdominal wall, in the prehepatic space. Direct sign of perforation may be detectable, particularly if they are associated with other sonographic abnormalities, called indirect signs, like thickened bowel loop and air bubbles in ascitic fluid or in a localized fluid collection, bowel or gallbladder thickened wall associated with decreased bowel motility or ileus. Neverthless, this exam has its own pitfalls. It is strongly operator-dependant; some machines have low-quality images that may not able to detect intraperitoneal free air; furthermore, some patients may be less cooperative to allow for scanning of different regions; sonography is also difficult in obese patients and with those having subcutaneous emphysema. Although CT has more accuracy in the detection of the site of perforation, ultrasound may be particularly useful also in patient groups where radiation burden should be limited notably children and pregnant women. PMID:23902744

  4. [Acute gastrointestinal bleeding].

    PubMed

    Baumbach, Robert; Faiss, Siegbert; Cordruwisch, Wolfgang; Schrader, Carsten

    2016-04-01

    Acute gastrointestinal bleeding is a common major emergency (Internal medical or gastroenterological or medical), approximately 85 % of which occur in the upper GI tract. It is estimated that about a half of upper GI bleeds are caused by peptic ulcers. Upper GI bleeds are associated with more severe bleeding and poorer outcomes when compared to middle or lower GI bleeds. Prognostic determinants include bleeding intensity, patient age, comorbid conditions and the concomitant use of anticoagulants. A focused medical history can offer insight into the bleeding intensity, location and potential cause (along with early risk stratification). Initial measures should focus on rapid assessment and resuscitation of unstable patients. The oesophagogastroduodenoscopy (OGD) is the gold standard method for localizing the source of bleeding and for interventional therapy. Bleeding as a result of peptic ulcers is treated endoscopically with mechanical and / or thermal techniques in combination with proton pump inhibitor (PPI) therapy. When variceal bleeding is suspected, pre-interventional use of vasopressin analogues and antibiotic therapies are recommended. Endoscopically, the first line treatment of esophageal varices is endoscopic ligature therapy, whereas that for gastric varices is the use of Histoacryl injection sclerotherapy. When persistent and continued massive hemorrhage occurs in a patient with known or suspected aortic disease the possibility of an aorto-enteric fistula must be considered. PMID:27078246

  5. The chicken gastrointestinal microbiome.

    PubMed

    Oakley, Brian B; Lillehoj, Hyun S; Kogut, Michael H; Kim, Woo K; Maurer, John J; Pedroso, Adriana; Lee, Margie D; Collett, Stephen R; Johnson, Timothy J; Cox, Nelson A

    2014-11-01

    The domestic chicken is a common model organism for human biological research and of course also forms the basis of a global protein industry. Recent methodological advances have spurred the recognition of microbiomes as complex communities with important influences on the health and disease status of the host. In this minireview, we provide an overview of the current state of knowledge of the chicken gastrointestinal microbiome focusing on spatial and temporal variability, the presence and importance of human pathogens, the influence of the microbiota on the immune system, and the importance of the microbiome for poultry nutrition. Review and meta-analysis of public data showed cecal communities dominated by Firmicutes and Bacteroides at the phylum level, while at finer levels of taxonomic resolution, a phylogenetically diverse assemblage of microorganisms appears to have similar metabolic functions that provide important benefits to the host as inferred from metagenomic data. This observation of functional redundancy may have important implications for management of the microbiome. We foresee advances in strategies to improve gut health in commercial operations through management of the intestinal microbiota as an alternative to in-feed subtherapeutic antibiotics, improvements in pre- and probiotics, improved management of polymicrobial poultry diseases, and better control of human pathogens via colonization reduction or competitive exclusion strategies. PMID:25263745

  6. Optical Microspherical Resonators for Biomedical Sensing

    PubMed Central

    Soria, Silvia; Berneschi, Simone; Brenci, Massimo; Cosi, Franco; Conti, Gualtiero Nunzi; Pelli, Stefano; Righini, Giancarlo C.

    2011-01-01

    Optical resonators play an ubiquitous role in modern optics. A particular class of optical resonators is constituted by spherical dielectric structures, where optical rays are total internal reflected. Due to minimal reflection losses and to potentially very low material absorption, these guided modes, known as whispering gallery modes, can confer the resonator an exceptionally high quality factor Q, leading to high energy density, narrow resonant-wavelength lines and a lengthy cavity ringdown. These attractive characteristics make these miniaturized optical resonators especially suited as laser cavities and resonant filters, but also as very sensitive sensors. First, a brief analysis is presented of the characteristics of microspherical resonators, of their fabrication methods, and of the light coupling techniques. Then, we attempt to overview some of the recent advances in the development of microspherical biosensors, underlining a number of important applications in the biomedical field. PMID:22346603

  7. Fluorescence dynamics of microsphere-adsorbed sunscreens

    NASA Astrophysics Data System (ADS)

    Krishnan, R.

    2005-03-01

    Sunscreens are generally oily substances which are prepared in organic solvents, emulsions or dispersions with micro- or nanoparticles. These molecules adsorb to and integrate into skin cells. In order to understand the photophysical properties of the sunscreen, we compare steady-state and time-resolved fluorescence in organic solvent of varying dielectric constant ɛ and adsorbed to polystyrene microspheres and dispersed in water. Steady-state fluorescence is highest and average fluorescence lifetime longest in toluene, the solvent of lowest ɛ. However, there is no uniform dependence on ɛ. Sunscreens PABA and padimate-O show complex emission spectra. Microsphere-adsorbed sunscreens exhibit highly non-exponential decay, illustrative of multiple environments of the adsorbed molecule. The heterogeneous fluorescence dynamics likely characterizes sunscreen adsorbed to cells.

  8. Cell specific, variable density, polymer microspheres

    NASA Technical Reports Server (NTRS)

    Yen, Shiao-Ping S. (Inventor); Rembaum, Alan (Inventor); Molday, Robert S. (Inventor)

    1978-01-01

    Biocompatible polymeric microspheres having an average diameter below about 3 microns and having a density at least 15% greater or lesser than organic cells and having covalent binding sites are provided in accordance with this invention. The microspheres are obtained by copolymerizing a hydroxy or amine substituted acrylic monomer such as hydroxyethylmethacrylate with a light or dense comonomer such as a fluoromonomer. A lectin or antibody is bound to the hydroxy or amine site of the bead to provide cell specificity. When added to a cell suspension the marked bead will specifically label the cell membrane by binding to specific receptor sites thereon. The labelled membrane can then be separated by density gradient centrifugation.

  9. Are Primo Vessels (PVs) on the Surface of Gastrointestine Involved in Regulation of Gastric Motility Induced by Stimulating Acupoints ST36 or CV12?

    PubMed Central

    Wang, Xiaoyu; Shi, Hong; Shang, Hongyan; Su, Yangshuai; Xin, Juanjuan; He, Wei; Jing, Xianghong; Zhu, Bing

    2012-01-01

    Previous studies showed primo vessels (PVs), which were referred to as Bonhan ducts (BHDs) and a part of circulatory system by Kim, located in different places of the body. The BHDs system was once considered as the anatomical basis of classical acupuncture meridian but not clearly identified by other investigators. In the present study, we tried to address the relationship between PVs and meridians through detecting the modulation of gastric motility by stimulating the PVs on the surface of stomach or intestine, as well as acupoints Zusanli (ST36) and Zhongwan (CV12). The results showed electric stimulation of the PVs had no effect on the gastric motility. While stimulating CV12 inhibited gastric motility significantly in PVs-intact and PVs-cut rats, there is no significant difference between the inhibition rate of the PVS-intact and the PVS-cut rats. Stimulating at ST36 increased gastric motility significantly in both the PVs-intact and the PVs-cut rats, yet there was no significant difference between the facilitation rate of the both groups. Taken together, the PVs on the surface of stomach or intestine did not mediate the regulation of gastric motility induced by stimulating at the acupoints ST36 or CV12. PMID:23091558

  10. Microencapsulation of Streptococcus equi antigens in biodegradable microspheres and preliminary immunisation studies.

    PubMed

    Azevedo, Ana F; Galhardas, Jorge; Cunha, António; Cruz, Patrícia; Gonçalves, Lídia M D; Almeida, António J

    2006-10-01

    Streptococcus equi subspecies equi is the causative agent of strangles, a bacterial infection of the respiratory tract of equidae. Current strategies to prevent strangles rely on antimicrobial therapy or immunisation with inactivated bacteria, S. equi bacterin, or M-like protein (SeM) extract. The aim of this work was to investigate whether immunisation with whole killed S. equi or a bacterial lysate entrapped in poly(lactide-co-glycolide) (PLGA) microspheres might induce protective immunity to mice. Animals were treated with a dose of antigen equivalent to 25 microg of SeM. For intranasal route animals were primed on days 1, 2 and 3 and were boosted on day 29. For intramuscular route, primary immunisation was carried out with a single injection on day 1 and animals were boosted on day 29. On day 43 animals were submitted to a challenge with a virulent strain of S. equi. Vaccination with antigen-containing microspheres induced higher serum antibody levels in mice treated by the intranasal route, whereas intramuscular immunisation did not reveal any difference between control and treatment groups. Microencapsulated antigens achieved to fully protect mice against experimental infection irrespective of the route of administration used. Following intranasal or intramuscular administration soluble antigen failed to protect mice against challenge. These studies indicate that PLGA microspheres are a potential carrier system for the delivery of S. equi antigens. PMID:16846728

  11. Electrospray formation of gelled nano-aluminum microspheres with superior reactivity.

    PubMed

    Wang, Haiyang; Jian, Guoqiang; Yan, Shi; DeLisio, Jeffery B; Huang, Chuan; Zachariah, Michael R

    2013-08-14

    Nanometallic fuels with high combustion enthalpy, such as aluminum, have been proposed as a potential fuel replacement for conventional metallic fuel to improve propellant performance in a variety of propulsive systems. Nevertheless, nanometallic fuels suffer from the processing challenges in polymer formulations such as increased viscosity and large agglomeration, which hinder their implementation. In this letter, we employ electrospray as a means to create a gel within a droplet, via a rapid, solvent evaporation-induced aggregation of aluminum nanoparticles, containing a small mass fraction of an energetic binder. The gelled aluminum microspheres were characterized and tested for their burning behavior by rapid wire heating ignition experiments. The gelled aluminum microspheres show enhanced combustion behavior compared to nanoaluminum, which possibly benefits from the nitrocellulose coating and the gelled microstructure, and is far superior to the corresponding dense micrometer-sized aluminum. PMID:23875780

  12. Sputter coating of microspherical substrates by levitation

    DOEpatents

    Lowe, A.T.; Hosford, C.D.

    Microspheres are substantially uniformly coated with metals or nonmetals by simltaneously levitating them and sputter coating them at total chamber pressures less than 1 torr. A collimated hole structure comprising a parallel array of upwardly projecting individual gas outlets is machined out to form a dimple. Glass microballoons,, which are particularly useful in laser fusion applications, can be substantially uniformly coated using the coating method and apparatus.

  13. Containerless polymeric microsphere production for biomedical applications

    NASA Technical Reports Server (NTRS)

    Rhim, W. K.; Hyson, M. T.; Chung, S. K.; Colvin, M.; Chang, M.

    1987-01-01

    A containerless method that produces highly uniform microspheres (greater than 50 microns in diameter) from many materials has been developed for biomedical applications. A piezoelectrically vibrated drop generator forms uniform (monodisperse) monomer droplets that are either electrostatistically levitated and polymerized using UV irradiation, or free-radical polymerized. Spheres of 2-hydroxyethyl methacrylate polymer have been produced with diameters of 155 microns + or - 1.57 percent.

  14. Sputter coating of microspherical substrates by levitation

    DOEpatents

    Lowe, Arthur T.; Hosford, Charles D.

    1981-01-01

    Microspheres are substantially uniformly coated with metals or nonmetals by simultaneously levitating them and sputter coating them at total chamber pressures less than 1 torr. A collimated hole structure 12 comprising a parallel array of upwardly projecting individual gas outlets 16 is machined out to form a dimple 11. Glass microballoons, which are particularly useful in laser fusion applications, can be substantially uniformly coated using the coating method and apparatus.

  15. Delivering Mesenchymal Stem Cells in Collagen Microsphere Carriers to Rabbit Degenerative Disc: Reduced Risk of Osteophyte Formation

    PubMed Central

    Li, Yuk Yin; Diao, Hua Jia; Chik, Tze Kit; Chow, Cin Ting; An, Xiao Meng; Leung, Victor; Cheung, Kenneth Man Chi

    2014-01-01

    Mesenchymal stem cells (MSCs) have the potential to treat early intervertebral disc (IVD) degeneration. However, during intradiscal injection, the vast majority of cells leaked out even in the presence of hydrogel carrier. Recent evidence suggests that annulus puncture is associated with cell leakage and contributes to osteophyte formation, an undesirable side effect. This suggests the significance of developing appropriate carriers for intradiscal delivery of MSCs. We previously developed a collagen microencapsulation platform, which entraps MSCs in a solid microsphere consisting of collagen nanofiber meshwork. These solid yet porous microspheres support MSC attachment, survival, proliferation, migration, differentiation, and matrix remodeling. Here we hypothesize that intradiscal injection of MSCs in collagen microspheres will outperform that of MSCs in saline in terms of better functional outcomes and reduced side effects. Specifically, we induced disc degeneration in rabbits and then intradiscally injected autologous MSCs, either packaged within collagen microspheres or directly suspended in saline, into different disc levels. Functional outcomes including hydration index and disc height were monitored regularly until 6 months. Upon sacrifice, the involved discs were harvested for histological, biochemical, and biomechanical evaluations. MSCs in collagen microspheres showed advantage over MSCs in saline in better maintaining the dynamic mechanical behavior but similar performance in hydration and disc height maintenance and matrix composition. More importantly, upon examination of gross appearance, radiograph, and histology of IVD, delivering MSCs in collagen microspheres significantly reduced the risk of osteophyte formation as compared to that in saline. This work demonstrates the significance of using cell carriers during intradiscal injection of MSCs in treating disc degeneration. PMID:24372278

  16. VEGF165A microsphere therapy for myocardial infarction suppresses acute cytokine release and increases microvascular density but does not improve cardiac function.

    PubMed

    Uitterdijk, André; Springeling, Tirza; van Kranenburg, Matthijs; van Duin, Richard W B; Krabbendam-Peters, Ilona; Gorsse-Bakker, Charlotte; Sneep, Stefan; van Haeren, Rorry; Verrijk, Ruud; van Geuns, Robert-Jan M; van der Giessen, Willem J; Markkula, Tommi; Duncker, Dirk J; van Beusekom, Heleen M M

    2015-08-01

    Angiogenesis induced by growth factor-releasing microspheres can be an off-the-shelf and immediate alternative to stem cell therapy for acute myocardial infarction (AMI), independent of stem cell yield and comorbidity-induced dysfunction. Reliable and prolonged local delivery of intact proteins such as VEGF is, however, notoriously difficult. Our objective was to create a platform for local angiogenesis in human-sized hearts, using polyethylene-glycol/polybutylene-terephthalate (PEG-PBT) microsphere-based VEGF165A delivery. PEG-PBT microspheres were biocompatible, distribution was size dependent, and a regimen of 10 × 10(6) 15-μm microspheres at 0.5 × 10(6)/min did not induce cardiac necrosis. Efficacy, studied in a porcine model of AMI with reperfusion rather than chronic ischemia used for most reported VEGF studies, shows that microspheres were retained for at least 35 days. Acute VEGF165A release attenuated early cytokine release upon reperfusion and produced a dose-dependent increase in microvascular density at 5 wk following AMI. However, it did not improve major variables for global cardiac function, left ventricular dimensions, infarct size, or scar composition (collagen and myocyte content). Taken together, controlled VEGF165A delivery is safe, attenuates early cytokine release, and leads to a dose-dependent increase in microvascular density in the infarct zone but does not translate into changes in global or regional cardiac function and scar composition. PMID:26024685

  17. IL-17a and IL-22 Induce Expression of Antimicrobials in Gastrointestinal Epithelial Cells and May Contribute to Epithelial Cell Defense against Helicobacter pylori

    PubMed Central

    Dixon, Beverly R. E. A.; Radin, Jana N.; Piazuelo, M. Blanca; Contreras, Diana C.; Algood, Holly M. Scott

    2016-01-01

    Helicobacter pylori colonization of the human stomach can lead to adverse clinical outcomes including gastritis, peptic ulcers, or gastric cancer. Current data suggest that in addition to bacterial virulence factors, the magnitude and types of immune responses influence the outcome of colonization. Specifically, CD4+ T cell responses impact the pathology elicited in response to H. pylori. Because gastritis is believed to be the initiating host response to more detrimental pathological outcomes, there has been a significant interest in pro-inflammatory T cell cytokines, including the cytokines produced by T helper 17 cells. Th17 cells produce IL-17A, IL-17F, IL-21 and IL-22. While these cytokines have been linked to inflammation, IL-17A and IL-22 are also associated with anti-microbial responses and control of bacterial colonization. The goal of this research was to determine the role of IL-22 in activation of antimicrobial responses in models of H. pylori infection using human gastric epithelial cell lines and the mouse model of H. pylori infection. Our data indicate that IL-17A and IL-22 work synergistically to induce antimicrobials and chemokines such as IL-8, components of calprotectin (CP), lipocalin (LCN) and some β-defensins in both human and primary mouse gastric epithelial cells (GEC) and gastroids. Moreover, IL-22 and IL-17A-activated GECs were capable of inhibiting growth of H. pylori in vitro. While antimicrobials were activated by IL-17A and IL-22 in vitro, using a mouse model of H. pylori infection, the data herein indicate that IL-22 deficiency alone does not render mice more susceptible to infection, change their antimicrobial gene transcription, or significantly change their inflammatory response. PMID:26867135

  18. IL-17a and IL-22 Induce Expression of Antimicrobials in Gastrointestinal Epithelial Cells and May Contribute to Epithelial Cell Defense against Helicobacter pylori.

    PubMed

    Dixon, Beverly R E A; Radin, Jana N; Piazuelo, M Blanca; Contreras, Diana C; Algood, Holly M Scott

    2016-01-01

    Helicobacter pylori colonization of the human stomach can lead to adverse clinical outcomes including gastritis, peptic ulcers, or gastric cancer. Current data suggest that in addition to bacterial virulence factors, the magnitude and types of immune responses influence the outcome of colonization. Specifically, CD4+ T cell responses impact the pathology elicited in response to H. pylori. Because gastritis is believed to be the initiating host response to more detrimental pathological outcomes, there has been a significant interest in pro-inflammatory T cell cytokines, including the cytokines produced by T helper 17 cells. Th17 cells produce IL-17A, IL-17F, IL-21 and IL-22. While these cytokines have been linked to inflammation, IL-17A and IL-22 are also associated with anti-microbial responses and control of bacterial colonization. The goal of this research was to determine the role of IL-22 in activation of antimicrobial responses in models of H. pylori infection using human gastric epithelial cell lines and the mouse model of H. pylori infection. Our data indicate that IL-17A and IL-22 work synergistically to induce antimicrobials and chemokines such as IL-8, components of calprotectin (CP), lipocalin (LCN) and some β-defensins in both human and primary mouse gastric epithelial cells (GEC) and gastroids. Moreover, IL-22 and IL-17A-activated GECs were capable of inhibiting growth of H. pylori in vitro. While antimicrobials were activated by IL-17A and IL-22 in vitro, using a mouse model of H. pylori infection, the data herein indicate that IL-22 deficiency alone does not render mice more susceptible to infection, change their antimicrobial gene transcription, or significantly change their inflammatory response. PMID:26867135

  19. Implication of combined PD-L1/PD-1 blockade with cytokine-induced killer cells as a synergistic immunotherapy for gastrointestinal cancer

    PubMed Central

    Geng, Ruixuan; Ge, Xiaoxiao; Tang, Wenbo; Chang, Jinjia; Wu, Zheng; Liu, Xinyang; Lin, Ying; Zhang, Zhe; Li, Jin

    2016-01-01

    Cytokine-induced killer (CIK) cells represent a realistic approach in cancer immunotherapy with confirmed survival benefits in the context of metastatic solid tumors. However, therapeutic effects are limited to a fraction of patients. In this study, immune-resistance elements and ideal combination therapies were explored. Initially, phenotypic analysis was performed to document CD3, CD56, NKG2D, DNAM-1, PD-L1, PD-1, CTLA-4, TIM-3, 2B4, and LAG-3 on CIK cells. Upon engagement of CIK cells with the tumor cells, expression of PD-1 on CIK cells and PD-L1 on both cells were up-regulated. Over-expression of PD-L1 levels on tumor cells via lentiviral transduction inhibited tumoricidal activity of CIK cells, and neutralizing of PD-L1/PD-1 signaling axis could enhance their tumor-killing effect. Conversely, blockade of NKG2D, a major activating receptor of CIK cells, largely caused dysfunction of CIK cells. Functional study showed an increase of NKG2D levels along with PD-L1/PD-1 blockade in the presence of other immune effector molecule secretion. Additionally, combined therapy of CIK infusion and PD-L1/PD-1 blockade caused a delay of in vivo tumor growth and exhibited a survival advantage over untreated mice. These results provide a preclinical proof-of-concept for simultaneous PD-L1/PD-1 pathways blockade along with CIK infusion as a novel immunotherapy for unresectable cancers. PMID:26871284

  20. Resorcinol-formaldehyde and carbon aerogel microspheres

    SciTech Connect

    Alviso, C.T.; Pekela, R.W.; Gross, J.; Lu, X.; Caps, R.; Fricke, J

    1996-04-01

    Aerogels are a unique class of materials possessing an open-cell structure with ultrafine cells/pores (<100nm), high surface area (400--1100 m{sup 2}/g), and a solid matrix composed of interconnected particles, fibers, or platelets with characteristic dimensions of 10nm. Although monolithic aerogels are ideal candidates for many applications (e.g. transparent window insulation), current processing methods have limited their introduction into the commercial marketplace. Our research focuses on the formation of resorcinol-formaldehyde (RF) aerogel microspheres which offer an attractive alternative to monolith production. An inverse emulsion polymerization is used to produce these spherical gel particles which undergo solvent exchange followed by supercritical drying with carbon dioxide. This process yields aerogel microspheres (10--80{mu} diameter) which can be used as loosely packed powders, compression molded into near-net shapes using a polymer binder, or used as additives in conventional foaming operations to produce new aerogel composites with superior thermal properties. The emulsification procedure, thermal characterization, mechanical properties, and potential applications of RF aerogel microspheres will be discussed.

  1. Pulmonary toxicity of Expancel microspheres in the rat.

    PubMed

    Porter, Dale W; Hubbs, Ann F; Baron, Paul A; Millecchia, Lyndell L; Wolfarth, Michael G; Battelli, Lori A; Schwegler-Berry, Diane E; Beighley, Christopher M; Andrew, Michael E; Castranova, Vincent

    2007-08-01

    Expancel microspheres are thermoplastic microspheres enclosing hydrocarbon. These microspheres expand when heated, producing many applications. Because they have unknown biological persistence and toxicity, we investigated the toxicity of two unexpanded (11.1 and 15.4 micro m mean diameter) and two expanded (3.1 and 5.5 micro m mass median aerodynamic diameter) Expancel microspheres in intratracheally-instilled, male, Sprague-Dawley rats. Pulmonary histopathology was evaluated at 28 days postexposure. Bronchoalveolar lavage fluid was evaluated at days 1, 7, 14, and 28 days postexposure. Crystalline silica was the positive control. By histopathology, both unexpanded and expanded microspheres caused granulomatous bronchopneumonia characterized by macrophages and giants cells, suggesting a persistent foreign body response. Expanded, but not unexpanded microspheres, also caused eosinophilic bronchitis and bronchiolitis, mucous metaplasia of airways and organized granulomatous inflammation with associated fibrosis and frequent airway obstruction. In contrast, alveolar macrophage activation, polymorphonuclear leukocytes, LDH and albumin in bronchoalveolar laveage fluid were initially elevated but returned to near control levels at 28 days, and did not reflect the persistent granulomatous bronchopneumonia caused by Expancel microspheres. These findings emphasize the importance of histopathology for evaluating pulmonary toxicity, suggest that Expancel microspheres are a potential occupational hazard, and indicate a need for additional studies on their potential pulmonary toxicity. [Supplementary materials are available for this article. Go to the publisher's online edition of Toxicology Pathology for the following free supplemental resources: motion within unexpected microspheres in H&E-stained lung (supplementary Figure 1); broncholar epithelium 28 days following exposure to 551 DE 20 microspheres (supplementary Figure 2); membrane ruffling and some instances of

  2. Bridging and caging in mixed suspensions of microsphere and adsorptive microgel.

    PubMed

    Zhao, Chuanzhuang; Yuan, Guangcui; Han, Charles C

    2014-11-28

    Gelation and glass transition in a mixed suspension of polystyrene (PS) microsphere and poly(N-isopropylacrylamide) (PNIPAM) microgel were studied as a function of the total colloid volume fraction and mixing ratio of these two components. The PNIPAM microgel, which is adsorbable on the PS microsphere surface, can induce bridging or stabilizing effect between microspheres depending on whether the volume fraction of microgel (ΦMG) is smaller or larger than the saturated adsorption concentration (Φ*MG) for a given volume fraction of the microsphere (ΦMS). Φ*MG is in a linear relationship with ΦMS, and the value of ΦMG/Φ*MG can be taken as an approximate measure of surface coverage. A state diagram of gelation and glass transition is constructed with the short-ranged attractive interaction, resulting from the well-defined bridging bonding. Keeping ΦMG/Φ*MG = 0.20 and increasing ΦMS from 0.25 to 0.55, the mixed suspension transforms from a bridging gel into an attractive glass; moreover, while keeping ΦMS = 0.45 and increasing ΦMG/Φ*MG from 0.20 to 1.2, the mixed suspension changes from a bridging gel into an attractive glass, and then to a repulsive glass. The bridging effect and the cage effect can be distinguished by the yielding behaviors in rheological measurements. In the nonlinear dynamic rheological experiments, one-step yielding, corresponding to the disconnecting of bridge network, is observed in the bridging gel, and one-step yielding, corresponding to the breaking of cage, is observed in the repulsive glass. However, a two-step yielding behavior is found in the bridging-induced attractive glass, which is attributed to the bridging effect of microgels and the caging effect of the dense environment. PMID:25280208

  3. Microsphere-based selective laser sintering for building macroporous bone scaffolds with controlled microstructure and excellent biocompatibility.

    PubMed

    Du, Yingying; Liu, Haoming; Shuang, Jiaqi; Wang, Jianglin; Ma, Jun; Zhang, Shengmin

    2015-11-01

    Fabrication of bulk biomaterials with controlled structures and excellent properties is increasingly important in tissue engineering, but remains a major challenge in the current stage. Herein we used selective laser sintering (SLS) to construct a series of three-dimensional (3D) bone scaffolds with uniform multi-scaled porosity, moderate mechanical properties as well as good biocompatibility. As starting architectural units for SLS, the pure microspheres of polycaprolactone (PCL) and the composite microspheres of PCL and hydroxyapatite (HA) were firstly synthesized via a modified solvent evaporation method, respectively. Our findings showed that the as-prepared microspheres exhibited the uniform size and monodispersity. Moreover, the microsphere-based 3D scaffolds generated by SLS technique showed a multi-scaled porous structure, and adequate mechanical features. Both in vitro and in vivo evaluations further demonstrated that the resultant SLS-derived scaffolds can not only manipulate multiple stem cell behaviors including promoting cell adhesion, supporting cell proliferation and inducing cell differentiation in vitro, but also showed an excellent histocompatibility and induced the vascularization of newly formed tissue in vivo. Consequently, our current study suggests a feasible and effective protocol for fabricating new biomimetic bone biomaterials via SLS technique, also paves a new way for other bulk biomaterials. PMID:26241919

  4. Listeria as an enteroinvasive gastrointestinal pathogen.

    PubMed

    Barbuddhe, Sukhadeo B; Chakraborty, Trinad

    2009-01-01

    The bacterium Listeria monocytogenes is the causative agent of listeriosis, a highly fatal opportunistic foodborne infection. Listeria spp. are isolated from a diversity of environmental sources, including soil, water, effluents, a large variety of foods, and the feces of humans and animals. Recent outbreaks demonstrated that L. monocytogenes can cause gastroenteritis in otherwise healthy individuals and more severe invasive disease in immunocompromised patients. Common symptoms include fever, watery diarrhea, nausea, headache, and pains in joints and muscles. The intestinal tract is the major portal of entry for L. monocytogenes, whereby strains penetrate the mucosal tissue either directly, via invasion of enterocytes, or indirectly, via active penetration of the Peyer's patches. Studies have revealed the strategy taken by the bacteria to overcome changes in oxygen tension, osmolarity, acidity, and the sterilizing effects of bile or antimicrobial peptides to adapt to conditions in the gut. In addition, L. monocytogenes has evolved species-specific strategies for intestinal entry by exploiting the interaction between the internalin protein and its receptor E-cadherin, or inducing diarrhea and an inflammatory response via the activity of its hemolytic toxin, listeriolysin. The ability of these bacteria to survive in bile-rich environments, and to induce depletion of sentinel cells such as Paneth cells that monitor the luminal burden of commensal bacteria, suggest strategies that have evolved to promote intestinal survival. Preexisting gastrointestinal disease may be a risk factor for infection of the gastrointestinal tract with L. monocytogenes. Currently, there is enough evidence to warrant consideration of L. monocytogenes as a possible etiology in outbreaks of febrile gastroenteritis, and for further studies to examine the genetic structure of Listeria strains that have a propensity to cause gastrointestinal versus systemic infections. PMID:19812983

  5. Acute gastrointestinal permeability responses to different non-steroidal anti-inflammatory drugs

    PubMed Central

    Smecuol, E; Bai, J; Sugai, E; Vazquez, H; Niveloni, S; Pedreira, S; Maurino, E; Meddings, J

    2001-01-01

    BACKGROUND AND AIMS—Non-steroidal anti-inflammatory drugs (NSAIDs) cause gastrointestinal damage both in the upper and lower gastrointestinal tract. New anti-inflammatory drugs have been developed in an attempt to improve their gastrointestinal side effect profile. Our objective was to compare the effect on gastrointestinal permeability of acute equieffective doses of four different NSAIDs; three were designed to reduce gastrointestinal mucosal injury.
MATERIALS—Healthy volunteers underwent sugar tests in a randomised fashion, 15 days apart, at: (1) baseline; (2) after two days of 75 mg slow release (microspheres) indomethacin; (3) after two days of 7.5 mg oral meloxicam which preferentially inhibits cyclooxygenase 2; and (4) after two days of 750 mg naproxen. A subgroup of subjects was tested after two days of 200 mg celecoxib. In each test, subjects ingested a solution containing sucrose, lactulose, and mannitol and sucralose, to evaluate gastroduodenal, intestinal, and colonic permeability, respectively.
RESULTS—Gastric permeability was significantly affected by naproxen (p<0.05) but not by slow release indomethacin, meloxicam, or celecoxib. Intestinal permeability was significantly increased by the first three NSAIDs (p<0.05) but not by celecoxib. Abnormal lactulose/mannitol ratios were observed in 42% of meloxicam treatments, in 62% during indomethacin, and in 75% of subjects treated with naproxen. Finally, colonic permeability, as measured by sucralose, was not significantly increased by any of the four drugs.
CONCLUSION—Our study provides evidence that the newly developed NSAIDs reduce gastric mucosal permeability significantly. However, most produced significant alteration of small intestinal permeability. In contrast, our results suggest that celecoxib seems to exhibit the most desirable gastrointestinal side effect profile.


Keywords: permeability; non-steroidal anti-inflammatory drugs; celecoxib; meloxican; small intestine

  6. Induction of high antitoxin titers against tetanus toxoid in rabbits by intranasal immunization with dextran microspheres.

    PubMed

    Sajadi Tabassi, S Abolghasem; Tafaghodi, Mohsen; Jaafari, Mahmoud Reza

    2008-08-01

    Poor absorption of protein antigens through the mucosal membranes necessitates the use of mucoadhesive delivery systems. Regarding the advantages of mucosal immunization and also the penetration enhancement potential of dextran microspheres, in this study the adjuvant potential of these microspheres was compared with CpG-ODN. Cross-linked dextran microspheres (CDMs) were loaded with tetanus toxoid (TT). In vitro release studies were performed in a model, simulating the nasal cavity. The immunoreactivity of encapsulated TT was assayed by ELISA. Membrane toxicity and local irritating potential of CDM was examined by erythrocyte hemolysis and nasal administration to human nose, respectively. The various formulations were nasally administered to rabbits (n=4). Alum-adsorbed TT (AATT) was injected as the positive control. The serum IgG and nasal lavage sIgA titers were determined by ELISA method. Serum antitoxin titers were determined by toxin neutralization (TN) bioassay method. Mean diameter of CDM was 128.1+/-25.8 microm. Mean encapsulation efficiency was 20.3+/-3.2% (n=3). Antigenicity of encapsulated TT was 90.5+/-1.8% (n=3) that of original TT. Hemolysis studies showed no membrane disruption by CDM and none of the human subjects reported nasal irritation. Among the nasally immunized animals, the highest antitoxin titers was seen in the group immunized with CDM+TT (P<0.0001). The serum IgG titers of the CDM+TT group was higher than the TT solution group (P<0.05). The adjuvant potentials of CDM and CpG-ODN in inducing IgG titers was not significantly different (P>0.05). The lowest sIgA titers in the bronchial lavage were seen in the group of animals received AATT parenterally. Considering the proper release characteristics, desirable preservation of the antigen activity of TT, good mucoadhesion properties and also safety of CDM+TT, these microspheres could be regarded as an efficient mucosal adjuvant and antigen delivery system. These microspheres could induce very

  7. Primary gastrointestinal lymphoma

    PubMed Central

    Aledavood, Amir; Nasiri, Mohammad Reza Ghavam; Memar, Bahram; Shahidsales, Soodabeh; Raziee, Hamid Reza; Ghafarzadegan, Kamran; Mohtashami, Samira

    2012-01-01

    Background: Extranodal lymphoma may arise anywhere outside lymph nodes mostly in the gastrointestinal (GI) tract as non-Hodgkin's disease. We reviewed the clinicopathological features and treatment results of patients with primary GI lymphoma. Materials and Methods: A total number of 30 cases with primary GI lymphoma were included in this study. Patients referred to the Radiation Oncology Department of Omid Hospital (Mashhad, Iran) during a 5-year period (2006-11). Clinical, paraclinical, and radiological data was collected from medical records of the patients. Results: Out of the 30 patients with primary GI lymphoma in the study, 12 were female (40%) and 18 were male (60%) (male to female ratio: 3/2). B symptoms were present in 27 patients (90%). Antidiuretic hormone (LDH) levels were elevated in 9 patients (32.1%). The most common primary site was stomach in 14 cases (46.7%). Other common sites included small intestine and colon each in 8 patients (26.7%). All patients had histopathologically proven non-Hodgkin's lymphoma. The most common histologic subtype was diffuse large B-cell lymphoma (DLBL) in 16 patients (53.3%). In addition, 28 patients (93.3%) received chemotherapy with cyclophosphamide, vincristine, doxorubicin, prednisolone (CHOP regimen). The median course of chemotherapy was 6 cources. Moreover, 8 patients (26.7%) received radiotherapy with cobalt 60. The median follow-up time was 26 months. The overall 5-year survival rate was 53% and the median survival time was 60 months. Conclusion: Primary GI lymphoma is commonly seen in stomach and small intestine and mostly is DLBCL or mucosa-associated lymphoid tissue (MALT) lymphoma. PMID:23626617

  8. [Functional and motility gastrointestinal disorders].

    PubMed

    Mearin, Fermín; Rey, Enrique; Balboa, Agustín

    2011-10-01

    As in previous years, a huge number of studies were presented at the Congress of the American Gastroenterology Association (Digestive Diseases Week [DDW]), some of which were better than others. The present article attempts to extract and summarize the most interesting findings reported. In general terms, certain technological advances have been consolidated, with full incorporation into clinical practice, such as impedancemetry and high-resolution manometry. New physiopathological data are coming to light that increasingly indicate the inextricable link between organic and psychological factors (the biopsychosocial model) in functional gastrointestinal disorders (FGID). Despite the high hopes that the Rome III criteria would improve the diagnosis of FGID and especially that of functional dyspepsia, their practical application has been fairly discouraging. Moreover, at least two studies have demonstrated that these criteria cannot be used to differentiate subtypes of functional dyspepsia and that there is wide overlap with gastroesophageal reflux disease. New data were presented on the role of genetic, microinflammatory and psychological factors in the etiopathogenesis of the two main FGID: functional dyspepsia and irritable bowel syndrome (IBS). The results on the safety and efficacy of acotiamide in functional dyspepsia and of linaclotide and prucalopride in idiopathic and IBS-associated constipation were also presented. Several studies, and even meta-analyses, have demonstrated the utility of biofeedback in the treatment of constipation. Even so, the efficacy of this therapy has been questioned due to certain methodological deficiencies in some studies. In DDW 2011, studies confirming the utility of biofeedback, whether hospital- or home-based were presented, in dyssynergy constipation. The present article also mentions certain features of special interest in the diagnosis and treatment of rumination syndrome, thoracic pain of possible esophageal origin and

  9. Pectin/zein microspheres as a sustained drug delivery system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A series of microspheres were prepared from pectins and corn proteins from various sources in the presence of the divalent ions calcium or zinc. The results showed that the yield of microsphere and the efficiency of drug incorporation were dependent on the type and ratio of biopolymers, the size of ...

  10. Novel sustained release microspheres for pulmonary drug delivery.

    PubMed

    Cook, Robert O; Pannu, Rupi K; Kellaway, Ian W

    2005-05-01

    A novel process for generating sustained release (SR) particles for pulmonary drug delivery is described. High purity nanoparticles of a hydrophilic, ionised drug are entrapped within hydrophobic microspheres using a spray-drying approach. Sustained release of the model drug, terbutaline sulphate (TS), from the microspheres was found to be proportional to drug loading and phospholipid content. Microspheres with a 33% drug loading exhibited sustained release of 32.7% over 180 min in phosphate buffer. Release was not significantly different in simulated lung fluids. No significant burst release was observed which suggested that nanoparticles were coated effectively during spray-drying. The absence of nanoparticles at the microsphere surface was confirmed with confocal microscopy. The sustained release microspheres were formulated as a carrier-free dry powder for inhalation, and exhibited a favourable Fine Particle Fraction (FPF) of 46.5+/-1.8% and Mass Median Aerodynamic Diameter (MMAD) of 3.93+/-0.12 microm. PMID:15866336

  11. Synthesis and surface modification of birefringent vaterite microspheres.

    PubMed

    Vogel, Robert; Persson, Martin; Feng, Chao; Parkin, Simon J; Nieminen, Timo A; Wood, Barry; Heckenberg, Norman R; Rubinsztein-Dunlop, Halina

    2009-10-01

    This paper reports on the synthesis of birefringent vaterite microspheres with narrow size distribution using a seeded growth method. In a post-treatment the microspheres were stabilized and functionalized through coating with a combination of organosilica and silica. The coating vastly enhanced the stability of the vaterite microspheres in biological buffers and allowed the attachment of biomolecules such as DNA or proteins. As an example, streptavidin was attached to the surface of the functionalized microspheres. These results pave the way for the use of birefringent vaterite particles for the micromanipulation of single biological molecules such as DNA or specific proteins in an optical trap capable of exerting and measuring torques. The stabilized birefringent microspheres may also find use for biosensor and biological screening applications. PMID:19788220

  12. A new method for the preparation of monoporous hollow microspheres.

    PubMed

    Chang, Ming-Wei; Stride, Eleanor; Edirisinghe, Mohan

    2010-04-01

    The feasibility of producing a hollow microsphere with a single hole in its shell by coaxial electrohydrodynamic atomization (CEHDA) is demonstrated. Polymethylsilsesquioxane (PMSQ) was used as a model shell material encapsulating a core of a volatile liquid, perfluorohexane (PFH), which was subsequently evaporated to produce the hollow microspheres. The diameters of the microspheres and of the single surface pore were controlled by varying the flow rate of the components, the concentration of the PMSQ solution, and the applied voltage in the CEHDA process. The particles were characterized by scanning electron microscopy, and the ranges obtained were 275-860 nm for the microsphere diameter and 35-135 nm for the pore size. The process overcomes several of the key problems associated with existing methods of monoporous microsphere formation including removing the need for elevated temperatures, multiple processing steps, and the use of surfactants and other additives. PMID:20095539

  13. Resolution enhancement phase-contrast imaging by microsphere digital holography

    NASA Astrophysics Data System (ADS)

    Wang, Yunxin; Guo, Sha; Wang, Dayong; Lin, Qiaowen; Rong, Lu; Zhao, Jie

    2016-05-01

    Microsphere has shown the superiority of super-resolution imaging in the traditional 2D intensity microscope. Here a microsphere digital holography approach is presented to realize the resolution enhancement phase-contrast imaging. The system is designed by combining the microsphere with the image-plane digital holography. A microsphere very close to the object can increase the resolution by transforming the object wave from the higher frequency to the lower one. The resolution enhancement amplitude and phase images can be retrieved from a single hologram. The experiments are carried on the 1D and 2D gratings, and the results demonstrate that the observed resolution has been improved, meanwhile, the phase-contrast image is obtained. The proposed method can improve the transverse resolution in all directions based on a single exposure. Furthermore, this system has extended the application of the microsphere from the conventional 2D microscopic imaging to 3D phase-contrast microscopic imaging.

  14. Synthesis and characterization of magnetic poly(glycidyl methacrylate) microspheres

    NASA Astrophysics Data System (ADS)

    Horák, Daniel; Petrovský, Eduard; Kapička, Aleš; Frederichs, Theodor

    2007-04-01

    Magnetic nanoparticles encapsulated in poly(glycidyl methacrylate) microspheres were prepared and their detailed structural and magnetic characteristics given. Iron oxide nanoparticles were obtained by chemical coprecipitation of Fe(II) and Fe(III) salts and stabilized with dextran, (carboxymethyl)dextran or tetramethylammonium hydroxide. The microspheres were prepared by emulsion or dispersion polymerization of glycidyl methacrylate in the presence of ferrofluid. The microspheres were uniform both in shape and usually also in size; their size distribution was narrow. All the magnetic parameters confirm superparamagnetic nature of the microspheres. Blocking temperature was not observed, suggesting the absence of magnetic interactions at low temperatures. This is most probably caused by complete encapsulation and the absence of agglomeration. Such microspheres can be used in biomedical applications.

  15. Hollow porous-wall glass microspheres for hydrogen storage

    DOEpatents

    Heung, Leung K.; Schumacher, Ray F.; Wicks, George G.

    2010-02-23

    A porous wall hollow glass microsphere is provided having a diameter range of between 1 to 200 microns, a density of between 1.0 to 2.0 gm/cc, a porous-wall structure having wall openings defining an average pore size of between 10 to 1000 angstroms, and which contains therein a hydrogen storage material. The porous-wall structure facilitates the introduction of a hydrogen storage material into the interior of the porous wall hollow glass microsphere. In this manner, the resulting hollow glass microsphere can provide a membrane for the selective transport of hydrogen through the porous walls of the microsphere, the small pore size preventing gaseous or liquid contaminants from entering the interior of the hollow glass microsphere.

  16. Labelling of silica microspheres with fluorescent lanthanide-doped LaF3 nanocrystals

    NASA Astrophysics Data System (ADS)

    Zhang, Yong; Lu, Meihua

    2007-07-01

    Fluorescent microspheres have been demonstrated to be useful in a variety of biological applications. Fluorescent silica or polymer microspheres have been produced by incorporation of chromophores into the microspheres, which usually produces microspheres with nonuniform sizes and reduced fluorescence. Here we present a simple and straightforward method to produce silica microspheres with fluorescent lanthanide-doped LaF3 nanocrystals grown on the surface. LaF3 nanocrystals are in situ grown on silica microspheres of different sizes to form a raspberry-like structure. The microspheres exhibit strong fluorescence and the colour could be altered by changing the lanthanide ions doped in LaF3 nanocrystals.

  17. Gastrointestinal Amyloidosis Presenting with Multiple Episodes of Gastrointestinal Bleeding

    SciTech Connect

    Kim, Sang Hyeon Kang, Eun Ju; Park, Jee Won; Jo, Jung Hyun; Kim, Soo Jin; Cho, Jin Han; Kang, Myong Jin; Park, Byeong Ho

    2009-05-15

    Amyloidosis is characterized by the extracellular deposition of amyloid protein in various organs. Gastrointestinal involvement in amyloidosis is common, but a diagnosis of amyloidosis is often delayed. Severe gastrointestinal hemorrhage in amyloidosis is rare but can be fatal in some cases. We experienced a case of a 49-year-old man who presented with recurrent massive hematochezia. Although embolization was performed eight times for bleeding from different sites of the small intestine, hematochezia did not cease. We report the case, with a review of the literature.

  18. Microsphere-Incorporated Hybrid Thermogel for Neuronal Differentiation of Tonsil Derived Mesenchymal Stem Cells.

    PubMed

    Patel, Madhumita; Moon, Hyo Jung; Jung, Bo Kyung; Jeong, Byeongmoon

    2015-07-15

    Neuronal differentiation of tonsil-derived mesenchymal stem cells (TMSCs) is investigated in a 3D hybrid system. The hybrid system is prepared by increasing the temperature of poly(ethylene glycol)-poly(l-alanine) aqueous solution to 37 °C through the heat-induced sol-to-gel transition, in which TMSCs and growth factor releasing microspheres are suspended. The in situ formed gel exhibits a modulus of 800 Pa at 37 °C, similar to that of brain tissue, and it is robust enough to hold the microspheres and cells during the 3D culture of TMSCs. The neuronal growth factors are released over 12-18 d, and the TMSCs in a spherical shape initially undergo multipolar elongation during the 3D culture. Significantly higher expressions of the neuronal biomarkers such as nuclear receptor related protein (Nurr-1), neuron specific enolase, microtubule associated protein-2, neurofilament-M, and glial fibrillary acidic protein are observed in both mRNA level and protein level in the hybrid systems than in the control experiments. This study proves the significance of a controlled drug delivery concept in tissue engineering or regenerative medicine, and a 3D hybrid system with controlled release of growth factors from microspheres in a thermogel can be a very promising tool. PMID:26033880

  19. Observations of transport of bacterial-like microspheres through beach sand

    NASA Astrophysics Data System (ADS)

    Gast, Rebecca J.; Elgar, Steve; Raubenheimer, Britt

    2015-04-01

    Often, there is an order of magnitude more fecal indicator bacteria (enterococci) in beach sand than in nearby water. Consequently, sand is considered a reservoir for these bacteria, potentially contributing to poor water quality, and raising questions regarding the human health risks associated with sand exposure. An integral aspect of the distribution and persistence of sand-associated enterococci is the transport of bacteria introduced into the beach environment. Here, plastic microspheres are used as a proxy to examine the wave-induced movement of bacterial-like particles through sand on an ocean beach. Laboratory tests suggest microspheres and bacteria move similarly through sand columns, and have qualitatively similar short-term adsorption-to-sand behavior. Microspheres buried ~0.05 m below the sand surface on an ocean beach moved rapidly [O(10-3) m/s] away from their initial location, both vertically into the ground water below the sand and horizontally seaward within the sediment matrix in response to waves running up the beach face and percolating through the sand.

  20. Design and application of chitosan microspheres as oral and nasal vaccine carriers: an updated review

    PubMed Central

    Islam, Mohammad Ariful; Firdous, Jannatul; Choi, Yun-Jaie; Yun, Cheol-Heui; Cho, Chong-Su

    2012-01-01

    Chitosan, a natural biodegradable polymer, is of great interest in biomedical research due to its excellent properties including bioavailability, nontoxicity, high charge density, and mucoadhesivity, which creates immense potential for various pharmaceutical applications. It has gelling properties when it interacts with counterions such as sulfates or polyphosphates and when it crosslinks with glutaraldehyde. This characteristic facilitates its usefulness in the coating or entrapment of biochemicals, drugs, antigenic molecules as a vaccine candidate, and microorganisms. Therefore, chitosan together with the advance of nanotechnology can be effectively applied as a carrier system for vaccine delivery. In fact, chitosan microspheres have been studied as a promising carrier system for mucosal vaccination, especially via the oral and nasal route to induce enhanced immune responses. Moreover, the thiolated form of chitosan is of considerable interest due to its improved mucoadhesivity, permeability, stability, and controlled/extended release profile. This review describes the various methods used to design and synthesize chitosan microspheres and recent updates on their potential applications for oral and nasal delivery of vaccines. The potential use of thiolated chitosan microspheres as next-generation mucosal vaccine carriers is also discussed. PMID:23271909

  1. Design and application of chitosan microspheres as oral and nasal vaccine carriers: an updated review.

    PubMed

    Islam, Mohammad Ariful; Firdous, Jannatul; Choi, Yun-Jaie; Yun, Cheol-Heui; Cho, Chong-Su

    2012-01-01

    Chitosan, a natural biodegradable polymer, is of great interest in biomedical research due to its excellent properties including bioavailability, nontoxicity, high charge density, and mucoadhesivity, which creates immense potential for various pharmaceutical applications. It has gelling properties when it interacts with counterions such as sulfates or polyphosphates and when it crosslinks with glutaraldehyde. This characteristic facilitates its usefulness in the coating or entrapment of biochemicals, drugs, antigenic molecules as a vaccine candidate, and microorganisms. Therefore, chitosan together with the advance of nanotechnology can be effectively applied as a carrier system for vaccine delivery. In fact, chitosan microspheres have been studied as a promising carrier system for mucosal vaccination, especially via the oral and nasal route to induce enhanced immune responses. Moreover, the thiolated form of chitosan is of considerable interest due to its improved mucoadhesivity, permeability, stability, and controlled/extended release profile. This review describes the various methods used to design and synthesize chitosan microspheres and recent updates on their potential applications for oral and nasal delivery of vaccines. The potential use of thiolated chitosan microspheres as next-generation mucosal vaccine carriers is also discussed. PMID:23271909

  2. Interventional nutrition for gastrointestinal disease.

    PubMed

    Hickman, M A

    1998-11-01

    Nutritional intervention plays a key role in the successful management of gastrointestinal disease. This article focuses on several novel areas of nutritional intervention that are becoming increasingly important in gastrointestinal disease, including short-chain fatty acids, omega-3 polyunsaturated fatty acids and glutamine. Short-chain fatty acids are the principal end-products of bacterial fermentation of dietary fibers and have profound effects on normal intestinal cell metabolism and proliferation. Short-chain fatty acids have the potential to improve overall intestinal health, stimulate intestinal healing, and decrease intestinal inflammation. Omega-3 fatty acids, from dietary sources or supplements, may also be useful in decreasing intestinal inflammation and in preventing intestinal cancer. Finally, glutamine also may play an important role in the nutritional management of gastrointestinal disease. PMID:9842113

  3. Therapeutic Vaccines for Gastrointestinal Cancers

    PubMed Central

    Rahma, Osama E.

    2011-01-01

    Despite progress in the management of gastrointestinal malignancies, these diseases remain devastating maladies. Conventional treatment with chemotherapy and radiation is still only partially effective and highly toxic. In the era of increasing knowledge of the molecular biology of tumors and the interaction between the tumor and immune system, the development of targeted agents, including cancer vaccines, has emerged as a promising modality. In this paper, we discuss the principals of vaccine development, and we review most of the published trials on gastrointestinal cancer vaccines that have been conducted over the last decade. Many antigens and various treatment approaches have already been tested in colon, pancreatic, and other cancers. Some of these approaches have already shown some clinical benefit. In this paper, we discuss these different strategies and some of the future directions for targeting gastrointestinal malignancies with vaccines. PMID:22298988

  4. Anthrax of the gastrointestinal tract.

    PubMed

    Sirisanthana, Thira; Brown, Arthur E

    2002-07-01

    When swallowed, anthrax spores may cause lesions from the oral cavity to the cecum. Gastrointestinal anthrax is greatly underreported in rural disease-endemic areas of the world. The apparent paucity of this form of anthrax reflects the lack of facilities able to make the diagnosis in these areas. The spectrum of disease, ranging from subclinical infection to death, has not been fully recognized. In some community-based studies, cases of gastrointestinal anthrax outnumbered those of cutaneous anthrax. The oropharyngeal variant, in particular, is unfamiliar to most physicians. The clinical features of oropharyngeal anthrax include fever and toxemia, inflammatory lesion(s) in the oral cavity or oropharynx, enlargement of cervical lymph nodes associated with edema of the soft tissue of the cervical area, and a high case-fatality rate. Awareness of gastrointestinal anthrax in a differential diagnosis remains important in anthrax-endemic areas but now also in settings of possible bioterrorism. PMID:12095428

  5. PCL-PDMS-PCL copolymer-based microspheres mediate cardiovascular differentiation from embryonic stem cells

    NASA Astrophysics Data System (ADS)

    Song, Liqing

    Poly-epsilon-caprolactone (PCL) based copolymers have received much attention as drug or growth factor delivery carriers and tissue engineering scaffolds due to their biocompatibility, biodegradability, and tunable biophysical properties. Copolymers of PCL and polydimethylsiloxane (PDMS) also have shape memory behaviors and can be made into thermoresponsive shape memory polymers for various biomedical applications such as smart sutures and vascular stents. However, the influence of biophysical properties of PCL-PDMS-PCL copolymers on stem cell lineage commitment is not well understood. In this study, PDMS was used as soft segments of varying length to tailor the biophysical properties of PCL-based co-polymers. While low elastic modulus (<10 kPa) of the tri-block copolymer PCL-PDMS-PCL affected cardiovascular differentiation of embryonic stem cells, the range of 60-100 MPa PCL-PDMS-PCL showed little influence on the differentiation. Then different size (30-140 mum) of microspheres were fabricated from PCL-PDMS-PCL copolymers and incorporated within embryoid bodies (EBs). Mesoderm differentiation was induced using bone morphogenetic protein (BMP)-4 for cardiovascular differentiation. Differential expressions of mesoderm progenitor marker KDR and vascular markers CD31 and VE-cadherin were observed for the cells differentiated from EBs incorporated with microspheres of different size, while little difference was observed for cardiac marker alpha-actinin expression. Small size of microspheres (30 mum) resulted in higher expression of KDR while medium size of microspheres (94 mum) resulted in higher CD31 and VE-cadherin expression. This study indicated that the biophysical properties of PCL-based copolymers impacted stem cell lineage commitment, which should be considered for drug delivery and tissue engineering applications.

  6. Gastrointestinal changes after bariatric surgery.

    PubMed

    Quercia, I; Dutia, R; Kotler, D P; Belsley, S; Laferrère, B

    2014-04-01

    Severe obesity is a preeminent health care problem that impacts overall health and survival. The most effective treatment for severe obesity is bariatric surgery, an intervention that not only maintains long-term weight loss but also is associated with improvement or remission of several comorbidies including type 2 diabetes mellitus. Some weight loss surgeries modify the gastrointestinal anatomy and physiology, including the secretions and actions of gut peptides. This review describes how bariatric surgery alters the patterns of gastrointestinal motility, nutrient digestion and absorption, gut peptide release, bile acids and the gut microflora, and how these changes alter energy homeostasis and glucose metabolism. PMID:24359701

  7. Nutritional support and gastrointestinal disease.

    PubMed

    Hennessy, K

    1989-06-01

    The use of nutritional support in patients with acute gastrointestinal disease requires a thorough knowledge of the pathophysiology and nutritional alterations that are caused by the disease process. Although nutritional therapy of a patient with gastrointestinal disease is not curative of the underlying disease, it does provide essential support to the patient, which improves response to, and eventual recovery from, illness. Special considerations need to be made to avoid complicating the patient's condition by inappropriate use of nutritional support solutions, which can lead to abnormal liver function. PMID:2498848

  8. Gastrointestinal changes after bariatric surgery

    PubMed Central

    Quercia, I.; Dutia, R.; Kotler, D.P.; Belsley, S.; Laferrère, B.

    2015-01-01

    Severe obesity is a preeminent health care problem that impacts overall health and survival. The most effective treatment for severe obesity is bariatric surgery, an intervention that not only maintains long-term weight loss but also is associated with improvement or remission of several comorbidies including type 2 diabetes mellitus. Some weight loss surgeries modify the gastrointestinal anatomy and physiology, including the secretions and actions of gut peptides. This review describes how bariatric surgery alters the patterns of gastrointestinal motility, nutrient digestion and absorption, gut peptide release, bile acids and the gut microflora, and how these changes alter energy homeostasis and glucose metabolism. PMID:24359701

  9. Evaluation of PEGylated exendin-4 released from poly (lactic-co-glycolic acid) microspheres for antidiabetic therapy.

    PubMed

    Lim, Sung Mook; Eom, Ha Na; Jiang, Hai Hua; Sohn, Minji; Lee, Kang Choon

    2015-01-01

    Peptide-based therapies have the potential to induce antibody formation if the molecules differ from a native human peptide. Several reports have disclosed the occurrence of antibody generation in a patient treated with exenatide. The immune response can be problematic from a clinical stand point, particularly if the antibodies neutralize the efficacy of the biotherapeutic agent or cause a general immune reaction. To overcome this limit, PEGylated exendin-4 analogs were designed and examined for metabolic stability and biological activity. To develop an extended release delivery system for exendin-4 for the safe and effective delivery of bioactive exendin-4 without peptide acylation and immunogenicity, PEGylated exendin-4 was encapsulated into poly (lactic-co-glycolic acid) (PLGA) microspheres by w/o/w double emulsion solvent evaporation method. Peptide-loaded microspheres were characterized in terms of morphology, particle diameter, and peptide encapsulation efficiency. Then, the release profile of the peptide from PLGA microspheres and the acylated products from PLGA polymer degradation was determined. The results obtained showed that the stability of exendin-4 was greatly improved by PEGylation. Moreover, eliminated acylation during PLGA polymer degradation in vitro and reduced immunogenicity in vivo were observed. The findings demonstrate that PEGylated exendin-4-loaded microspheres may be a safe and biocompatible system for clinical development. PMID:25407390

  10. Factors affecting size and swelling of poly(ethylene glycol) microspheres formed in aqueous sodium sulfate solutions without surfactants.

    PubMed

    Nichols, Michael D; Scott, Evan A; Elbert, Donald L

    2009-10-01

    The LCST behavior of poly(ethylene glycol) (PEG) in aqueous sodium sulfate solutions was exploited to fabricate microspheres without the use of other monomers, polymers, surfactants or organic solvents. Reactive PEG derivatives underwent thermally induced phase separation to produce spherical PEG-rich domains that coarsened in size pending gelation, resulting in stable hydrogel microspheres between approximately 1 and 100 microns in size. The time required to reach the gel point during the coarsening process and the extent of crosslinking after gelation both affected the final microsphere size and swelling ratio. The gel point could be varied by pre-reaction of the PEG derivatives below the cloud point, or by controlling pH and temperature above the cloud point. Pre-reaction brought the PEG derivatives closer to the gel point prior to phase separation, while the pH and temperature influenced the rate of reaction. Dynamic light scattering indicated a percolation-to-cluster transition about 3-5 min following phase separation. The mean radius of PEG-rich droplets subsequently increased with time to the 1/4th power until gelation. PEG microspheres produced by these methods with controlled sizes and densities may be useful for the production of modular scaffolds for tissue engineering. PMID:19615738

  11. Fabrication of superparamagnetic magnetite/poly(styrene-co-12-acryloxy-9-octadecenoic acid) nanocomposite microspheres with controllable structure.

    PubMed

    Yang, Song; Liu, Huarong; Huang, Haofeng; Zhang, Zhicheng

    2009-10-15

    We herein report a novel and facile approach to the fabrication of the superparamagnetic magnetite/poly(styrene-co-12-acryloxy-9-octadecenoic acid) nanocomposite microspheres with controllable structure via gamma-ray radiation induced inverse emulsion polymerization under room temperature and at ambient pressure. 12-Acryloxy-9-octadecenoic acid (AOA, containing part of sodium salts Na-AOA) as a surfactant can also copolymerize with the styrene. It is interesting that just by changing the added amount of styrene, the magnetic hollow spheres with different wall thickness and various sizes of core, up to the magnetic solid spheres, can be obtained. The final products were thoroughly characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron diffraction (TEM), field-emission scanning electron microscopy (FESEM), thermogravimetric analysis (TGA) which showed the formation of magnetite/poly(styrene-co-AOA) nanocomposite microspheres. Magnetic hysteresis loop measurements showed that the magnetic nanocomposite microspheres exhibited superparamagnetism, which should make them have potential applications in biotechnology and biomedicine. Furthermore, we also proposed a possible formation mechanism of these magnetic microspheres with different morphologies. PMID:19640548

  12. Measurement of thermal diffusivity of depleted uranium metal microspheres

    NASA Astrophysics Data System (ADS)

    Humrickhouse-Helmreich, Carissa J.; Corbin, Rob; McDeavitt, Sean M.

    2014-03-01

    The high void space of nuclear fuels composed of homogeneous uranium metal microspheres may allow them to achieve ultra-high burnup by accommodating fuel swelling and reducing fuel/cladding interactions; however, the relatively low thermal conductivity of microsphere nuclear fuels may limit their application. To support the development of microsphere nuclear fuels, an apparatus was designed in a glovebox and used to measure the apparent thermal diffusivity of a packed bed of depleted uranium (DU) microspheres with argon fill in the void spaces. The developed Crucible Heater Test Assembly (CHTA) recorded radial temperature changes due to an initial heat pulse from a central thin-diameter cartridge heater. Using thermocouple positions and time-temperature data, the apparent thermal diffusivity was calculated. The thermal conductivity of the DU microspheres was calculated based on the thermal diffusivity from the CHTA, known material densities and specific heat capacities, and an assumed 70% packing density based on prior measurements. Results indicate that DU metal microspheres have very low thermal conductivity, relative to solid uranium metal, and rapidly form an oxidation layer even in a low oxygen environment. At 500 °C, the thermal conductivity of the DU metal microsphere bed was 0.431 ± 0.0560 W/m-K compared to the literature value of approximately 32 W/m-K for solid uranium metal.

  13. A novel chemistry for conjugating pneumococcal polysaccharides to Luminex microspheres.

    PubMed

    Schlottmann, Sonela A; Jain, Neil; Chirmule, Narendra; Esser, Mark T

    2006-02-20

    Here we describe a novel method to conjugate pneumococcal polysaccharides (PnPS) to Luminex microspheres for use in serological assays. 4-(4,6-dimethoxy[1,3,5]triazin-2-yl)-4-methyl-morpholinium (DMTMM) modification of PnPS and conjugation to carboxyl functional groups on Luminex microspheres (COOH-DMTMM method) was shown to be a reproducible chemistry that efficiently conjugated PnPS to Luminex microspheres without affecting the antigenicity of a broad set of PnPS. The COOH-DMTMM method was compared to three other methods for robustness, reproducibility and effect on PnPS antigenicity in a multiplexed assay format. The other methods examined included adsorption of the unmodified PnPS to Luminex microspheres, oxidation of the PnPS to conjugate them to amino-modified microspheres using carbodiimide chemistry and poly-l-lysine modification of the PnPS before conjugating to carboxy Luminex microspheres using carbodiimide chemistry. Of the four methods, the COOH-DMTMM chemistry was shown to be a robust methodology, producing stable PnPS coupled microspheres with a 4-log dynamic range and low cross-reactivity when used in a PnPS-specific IgG serology assay. This novel chemistry should be useful for developing serological assays to measure antibodies to polysaccharides for use in vaccine and epidemiology studies. PMID:16448665

  14. Measurements of extrinsic fluorescence in Intralipid and polystyrene microspheres

    PubMed Central

    Du Le, Vinh Nguyen; Nie, Zhaojun; Hayward, Joseph E.; Farrell, Thomas J.; Fang, Qiyin

    2014-01-01

    The fluorescence of Intralipid and polystyrene microspheres with sphere diameter of 1 µm at a representative lipid and microsphere concentration for simulation of mucosal tissue scattering has not been a subject of extensive experimental study. In order to elucidate the quantitative relationship between lipid and microsphere concentration and the respective fluorescent intensity, the extrinsic fluorescence spectra between 360 nm and 650 nm (step size of 5 nm) were measured at different lipid concentrations (from 0.25% to 5%) and different microsphere concentrations (0.00364, 0.0073, 0.0131 spheres per cubic micrometer) using laser excitation at 355 nm with pulse energy of 2.8 µJ. Current findings indicated that Intralipid has a broadband emission between 360 and 650 nm with a primary peak at 500 nm and a secondary peak at 450 nm while polystyrene microspheres have a single peak at 500 nm. In addition, for similar scattering properties the fluorescence of Intralipid solutions is approximately three-fold stronger than that of the microsphere solutions. Furthermore, Intralipid phantoms with lipid concentrations ~2% (simulating the bottom layer of mucosa) produce up to seven times stronger fluorescent emission than phantoms with lipid concentration ~0.25% (simulating the top layer of mucosa). The fluoresence decays of Intralipid and microsphere solutions were also recorded for estimation of fluorescence lifetime. PMID:25136497

  15. What Should You Ask Your Doctor about Gastrointestinal Carcinoid Tumors?

    MedlinePlus

    ... gastrointestinal carcinoid tumors? What should you ask your doctor about gastrointestinal carcinoid tumors? It is important to ... Staging Treating Gastrointestinal Carcinoid Tumors Talking With Your Doctor After Treatment What`s New in Gastrointestinal Carcinoid Tumors ...

  16. [Adherence to the gastrointestinal wall and potential pathogenicity of gastrointestinal germs].

    PubMed

    Lorenz, A; Schulze, J; Grütte, F K

    1984-01-01

    Under certain circumstances--invasion of adhesive germs, abundant reproduction of the germs at the mucosa, a lowered resistance of the body--the adhesive flora can become a pathogenic factor itself. All hitherto known researchers point out that, in this connection, adhesions at the small intestinal wall is of main importance, as could be shown by our experiment with gnotobiotic rats, too. From the results of our experiments regarding the adhesion mechanisms, we conclude that the possibilities of prophylaxis and therapy of gastrointestinal disturbances induced by microbial effects could be extended by means of aimed inhibition of such adhesion forces. PMID:6493322

  17. Hippo pathway regulation of gastrointestinal tissues.

    PubMed

    Yu, Fa-Xing; Meng, Zhipeng; Plouffe, Steven W; Guan, Kun-Liang

    2015-01-01

    The Hippo pathway plays a crucial role in regulating tissue homeostasis and organ size, and its deregulation is frequently observed in human cancer. Yap is the major effector of and is inhibited by the Hippo pathway. In mouse model studies, inducible Yap expression in multiple tissues results in organ overgrowth. In the liver, knockout of upstream Hippo pathway components or transgenic expression of Yap leads to liver enlargement and hepatocellular carcinoma. In the small intestine or colon, deletion of upstream Hippo pathway components also results in expansion of intestinal progenitor cells and eventual development of adenomas. Genetic deletion of Yap in the intestine does not change the intestinal structure, but Yap is essential for intestinal repair upon certain types of tissue injury. The function of the Hippo pathway has also been studied in other gastrointestinal tissues, including the pancreas and stomach. Here we provide a brief overview of the Hippo pathway and discuss the physiological and pathological functions of this tumor suppressor pathway in gastrointestinal tissues. PMID:25293527

  18. Removal of chloroform from biodegradable therapeutic microspheres by radiolysis.

    PubMed

    Zielhuis, S W; Nijsen, J F W; Dorland, L; Krijger, G C; van Het Schip, A D; Hennink, W E

    2006-06-01

    Radioactive holmium-166 loaded poly(l-lactic acid) microspheres are promising systems for the treatment of liver malignancies. These microspheres are loaded with holmium acetylacetonate (HoAcAc) and prepared by a solvent evaporation method using chloroform. After preparation the microspheres (Ho-PLLA-MS) are activated by neutron irradiation in a nuclear reactor. It was observed that relatively large amounts of residual chloroform (1000-6000 ppm) remained in the microspheres before neutron irradiation. Since it is known that chloroform is susceptible for high-energy radiation, we investigated whether neutron and gamma irradiation could result in the removal of residual chloroform in HoAcAc-loaded and placebo PLLA-MS by radiolysis. To investigate this, microspheres with relatively high and low amounts of residual chloroform were subjected to irradiation. The effect of irradiation on the residual chloroform levels as well as other microsphere characteristics (morphology, size, crystallinity, molecular weight of PLLA and degradation products) were evaluated. No chloroform in the microspheres could be detected after neutron irradiation. This was also seen for gamma irradiation at a dose of 200 kGy phosgene, which can be formed as the result of radiolysis of chloroform, was not detected with gas chromatography-mass spectrometry (GC-MS). A precipitation titration showed that radiolysis of chloroform resulted in the formation of chloride. Gel permeation chromatography and differential scanning calorimetry showed a decrease in molecular weight of PLLA and crystallinity, respectively. However, no differences were observed between irradiated microsphere samples with high and low initial amounts of chloroform. In conclusion, this study demonstrates that neutron and gamma irradiation results in the removal of residual chloroform in PLLA-microspheres. PMID:16549282

  19. Protocell-like Microspheres from Thermal Polyaspartic Acid

    NASA Astrophysics Data System (ADS)

    Bahn, Peter R.; Pappelis, Aristotel; Bozzola, John

    2006-12-01

    One of the most prominent amino acids to appear in monomer-generating origin-of-life experiments is aspartic acid. Hugo Schiff found in 1897 that aspartic acid polymerizes when heated to form polyaspartylimide which hydrolyzes in basic aqueous solution to form thermal polyaspartic acid which is a branched polypeptide. We recently reported at the ISSOL 2005 Conference that commercially made thermal polyaspartic acid forms microspheres when heated in boiling water and allowed to cool. In a new experiment we heated aspartic acid at 180°C for up to 100 h to form thermal polyaspartylimide which when heated in boiling water without addition of base hydrolyzed to form thermal polyaspartic acid which upon cooling formed microspheres. Thermal polyaspartic acid microspheres appear protocell-like in the sense of being prebiotically plausible lattices or containers that could eventually have been filled with just the right additions of primordial proteins, nucleic acids, lipids, and metabolites so as to constitute protocells capable of undergoing further chemical and biological evolution. Thermal polyaspartic acid microspheres are extremely simple models of protocells that are more amenable to precise quantitative experimental investigation than the proteinoid microspheres of Sidney W. Fox. We present here scanning electron microscope images of such thermal polyaspartic acid microspheres. Figure 1 shows thermal polyaspartic acid microspheres from l-aspartic acid heated at 180°C for 50 h, at a magnification of 3,500×. Figure 2 shows thermal polyaspartic acid microspheres from the same sample at a magnification of 7,000×. The thermal polyaspartic acid microspheres have a diameter of approximately 1 μm These images were viewed with a Hitachi S2460N scanning electron microscope at 20 kV acceleration voltage. [Figure not available: see fulltext.][Figure not available: see fulltext.

  20. Differential regulation of angiogenesis using degradable VEGF-binding microspheres.

    PubMed

    Belair, David G; Miller, Michael J; Wang, Shoujian; Darjatmoko, Soesiawati R; Binder, Bernard Y K; Sheibani, Nader; Murphy, William L

    2016-07-01

    Vascular endothelial growth factor (VEGF) spatial and temporal activity must be tightly controlled during angiogenesis to form perfusable vasculature in a healing wound. The native extracellular matrix (ECM) regulates growth factor activity locally via sequestering, and researchers have used ECM-mimicking approaches to regulate the activity of VEGF in cell culture and in vivo. However, the impact of dynamic, affinity-mediated growth factor sequestering has not been explored in detail with biomaterials. Here, we sought to modulate VEGF activity dynamically over time using poly(ethylene glycol) microspheres containing VEGF-binding peptides (VBPs) and exhibiting varying degradation rates. The degradation rate of VBP microspheres conferred a differential ability to up- or down-regulate VEGF activity in culture with primary human endothelial cells. VBP microspheres with fast-degrading crosslinks reduced VEGF activity and signaling, while VBP microspheres with no inherent degradability sequestered and promoted VEGF activity in culture with endothelial cells. VBP microspheres with degradable crosslinks significantly reduced neovascularization in vivo, but neither non-degradable VBP microspheres nor bolus delivery of soluble VBP reduced neovascularization. The covalent incorporation of VBP to degradable microspheres was required to reduce neovascularization in a mouse model of choroidal neovascularization in vivo, which demonstrates a potential clinical application of degradable VBP microspheres to reduce pathological angiogenesis. The results herein highlight the ability to modulate the activity of a sequestered growth factor by changing the crosslinker identity within PEG hydrogel microspheres. The insights gained here may instruct the design and translation of affinity-based growth factor sequestering biomaterials for regenerative medicine applications. PMID:27061268

  1. The affinity of magnetic microspheres for Schistosoma eggs.

    PubMed

    Candido, Renata R F; Favero, Vivian; Duke, Mary; Karl, Stephan; Gutiérrez, Lucía; Woodward, Robert C; Graeff-Teixeira, Carlos; Jones, Malcolm K; St Pierre, Timothy G

    2015-01-01

    Schistosomiasis is a chronic parasitic disease of humans, with two species primarily causing the intestinal infection: Schistosoma mansoni and Schistosoma japonicum. Traditionally, diagnosis of schistosomiasis is achieved through direct visualisation of eggs in faeces using techniques that lack the sensitivity required to detect all infections, especially in areas of low endemicity. A recently developed method termed Helmintex™ is a very sensitive technique for detection of Schistosoma eggs and exhibits 100% sensitivity at 1.3 eggs per gram of faeces, enough to detect even low-level infections. The Helminthex™ method is based on the interaction of magnetic microspheres and schistosome eggs. Further understanding the underlying egg-microsphere interactions would enable a targeted optimisation of egg-particle binding and may thus enable a significant improvement of the Helmintex™ method and diagnostic sensitivity in areas with low infection rates. We investigated the magnetic properties of S. mansoni and S. japonicum eggs and their interactions with microspheres with different magnetic properties and surface functionalization. Eggs of both species exhibited higher binding affinity to the magnetic microspheres than the non-magnetic microspheres. Binding efficiency was further enhanced if the particles were coated with streptavidin. Schistosoma japonicum eggs bound more microspheres compared with S. mansoni. However, distinct differences within eggs of each species were also observed when the distribution of the number of microspheres bound per egg was modelled with double Poisson distributions. Using this approach, both S. japonicum and S. mansoni eggs fell into two groups, one having greater affinity for magnetic microspheres than the other, indicating that not all eggs of a species exhibit the same binding affinity. Our observations suggest that interaction between the microspheres and eggs is more likely to be related to surface charge-based electrostatic

  2. Common problems in gastrointestinal radiology

    SciTech Connect

    Thompson, W.M.

    1989-01-01

    This book covers approximately 70 common diagnostic problems in gastro-intestinal radiology. Each problem, includes a short illustrated case history, a discussion of the radiologic findings, a general discussion of the case, the differential diagnosis, a description of the management of the problem or procedure used, and, where appropriate, the results of the therapy suggested.

  3. [Motility and functional gastrointestinal disorders].

    PubMed

    Mearin, Fermín; Rey, Enrique; Balboa, Agustín

    2014-09-01

    This article discusses the studies on functional and motor gastrointestinal disorders presented at the 2014 Digestive Diseases Week conference that are of greatest interest to us. New data have been provided on the clinical importance of functional gastrointestinal disorders, with recent prevalence data for irritable bowel syndrome and fecal incontinence. We know more about the pathophysiological mechanisms of the various functional disorders, especially irritable bowel syndrome, which has had the largest number of studies. Thus, we have gained new data on microinflammation, genetics, microbiota, psychological aspects, etc. Symptoms such as abdominal distension have gained interest in the scientific community, both in terms of patients with irritable bowel syndrome and those with constipation. From the diagnostic point of view, the search continues for a biomarker for functional gastrointestinal disorders, especially for irritable bowel syndrome. In the therapeutic area, the importance of diet for these patients (FODMAP, fructans, etc.) is once again confirmed, and data is provided that backs the efficacy of already marketed drugs such as linaclotide, which rule out the use of other drugs such as mesalazine for patients with irritable bowel syndrome. This year, new forms of drug administration have been presented, including metoclopramide nasal sprays and granisetron transdermal patches for patients with gastroparesis. Lastly, a curiosity that caught our attention was the use of a vibrating capsule to stimulate gastrointestinal transit in patients with constipation. PMID:25294261

  4. Gastrointestinal endoscopy: past and future

    PubMed Central

    Sivak, M V

    2006-01-01

    The former editor of Gastrointestinal Endoscopy reflects on the history of endoscopy, which reveals much about the mechanisms whereby innovation occurred, and attempts to forecast the future. Endoscopic technological development in most industrialised countries will be determined largely by various combinations of many external factors together with the further development of virtual imaging PMID:16849338

  5. Development of packaged silica microspheres coupled with tapered optical microfibres

    NASA Astrophysics Data System (ADS)

    Wang, Pengfei; Madugani, Ramgopal; Zhao, Haoyu; Ward, Jonathan; Yang, Yong; Farrell, Gerald; Brambilla, Gilberto; Nic Chormaic, Síle

    2016-03-01

    In this research, we present a packaged add-drop filter composed of a silica microsphere resonator and a strongly coupled optical microfiber coupler. A one-step fabrication process using UV curable epoxy is shown to stabilize the microsphere resonator coupled to the microfiber coupler, which is used as add and drop ports. A high Q-factor of 3×107 is obtained at around 780 nm from the packaged microspheres coupled with the microfiber coupler in the add-drop configuration.

  6. Effect of size of silica microspheres on photonic band gap

    SciTech Connect

    Dhiman, N. Sharma, A. Gathania, A. K.; Singh, B. P.

    2014-04-24

    In present work photonic crystals of different size of silica microspheres have been fabricated. The optical properties of these developed photonic crystals have been studied using UV-visible spectroscopy. UV-visible spectroscopy shows that they have photonic band gap that can be tuned in visible and infrared regime by changing the size of silica microspheres. The photonic band gap structures of these photonic crystals have been calculated using MIT photonic band gap package. It also reveals that with the increase in size of silica microspheres the photonic band gap shifts to lower energy region.

  7. Preparation of microspheres of water-soluble pharmaceuticals.

    PubMed

    Huang, H P; Ghebre-Sellassie, I

    1989-01-01

    An emulsion-solvent evaporation procedure involving the dispersion of an alcoholic solution of an active in liquid paraffin was used to prepare microspheres of water-soluble pharmaceuticals using ethylcellulose as a carrier. The effects of surfactant, plasticizer, drug loading, and agitation speed on drug release rate from the microspheres were evaluated. The release rates of water-soluble drugs from microspheres, ranging from 100 and 500 microns in diameter, were sustained over an extended time and were found to be related to the ratio of drug to polymer in the final product. PMID:2723966

  8. Locomotion of microspheres for super-resolution imaging

    NASA Astrophysics Data System (ADS)

    Krivitsky, Leonid A.; Wang, Jia Jun; Wang, Zengbo; Luk'yanchuk, Boris

    2013-12-01

    Super-resolution virtual imaging by micron sized transparent beads (microspheres) was recently demonstrated by Wang et al. Practical applications in microscopy require control over the positioning of the microspheres. Here we present a method of positioning and controllable movement of a microsphere by using a fine glass micropipette. This allows sub-diffraction imaging at arbitrary points in three dimensions, as well as the ability to track moving objects. The results are relevant to a broad scope of applications, including sample inspection, microfabrication, and bio-imaging.

  9. Observation of whispering gallery modes in microtube-microspheres system

    NASA Astrophysics Data System (ADS)

    Li, Hanyang; Hao, Sue; Qiang, Liangsheng; Li, Jin; Zhang, Yundong

    2013-06-01

    We proposed that a fluorescent microsphere with diameter of 6 μm was manipulated into a microtube with inner diameter of 6.2 μm. The whispering gallery modes (WGMs) of fluorescence resonance were observed by 532 nm laser pumping the microspheres-mircotube system. Another microsphere with the same diameter was manipulated into the microtube and mode splitting in the system of two spheres in contact in the mircotube was demonstrated. We also discussed relationship between WGMs peak intensity and the excitation power. The scheme will bring more insight into the applications of WGMs for biomedical diagnostics and microfluidics.

  10. Mucoadhesive microspheres containing anti-hypertensive agent: formulation and characterization.

    PubMed

    Patel, Ankita Sunilbhai; Saikat, Pande; Pravinbhai, Patel Ronakkumar

    2014-01-01

    The spherical microspheres consisting of Furosemide loaded sodium alginate and along with HPMC E50 or sodium CMC as mucoadhesive polymers in different ratios were prepared using ionic gelation technique. Calcium chloride was used as crosslinking, to retard the drug release from the mucoadhesive microspheres. The prepared mucoadhesive microspheres were subjected for evaluation of various parameters like production yield, particle size, encapsulation efficiency, mucoadhesion test and in vitro dissolution profile studies. Formulations were subjected to DSC study and SEM analysis. The in vitro release data were well fit into Higuchi and Korsmeyer-Peppas model and followed non-Fickian diffusion mechanism. PMID:24410197

  11. Protein specific fluorescent microspheres for labelling a protein

    NASA Technical Reports Server (NTRS)

    Rembaum, Alan (Inventor)

    1982-01-01

    Highly fluorescent, stable and biocompatible microspheres are obtained by copolymerizing an acrylic monomer containing a covalent bonding group such as hydroxyl, amine or carboxyl, for example, hydroxyethylmethacrylate, with an addition polymerizable fluorescent comonomer such as dansyl allyl amine. A lectin or antibody is bound to the covalent site to provide cell specificity. When the microspheres are added to a cell suspension the marked microspheres will specifically label a cell membrane by binding to a specific receptor site thereon. The labeled membrane can then be detected by fluorescence of the fluorescent monomer.

  12. Preparation and properties of polyvinyl alcohol microspheres

    SciTech Connect

    Campbell, J.H.; Grens, J.Z.; Poco, J.F.; Ives, B.H.

    1986-06-01

    Polyvinyl alcohol (PVA) microspheres, having a size range of approx.150- to 250-..mu..m diameter with 1- to 5-..mu..m wall thickness, have been fabricated using a solution droplet technique. The spheres were developed for possible use on the Lawrence Livermore National Laboratory (LLNL) Inertial Confinement Fusion (ICF) Program. PVA, a polymer chosen based on earlier survey work carried out at KMS Fusion, Inc., has good strength, low hydrogen permeability, is optically transparent, and water soluble. The latter property makes it safe and easy to use in our droplet generator system. A unique dual-orifice droplet generator was used to prepare the spheres. The droplet generator operating conditions and the column processing parameters were chosen using results from our 1-D model calculations as a guide. The polymer microsphere model is an extension of the model we developed to support the glass sphere production. After preparation, the spheres were physically characterized for surface quality, sphericity, wall thickness (and uniformity), and size. We also determined the buckling pressure for both uncoated and CH-coated spheres. Radiation stability to beta decay (from tritium) was evaluated by exposing the spheres to a 7-keV electron beam. The results from these and other physical property measurements are presented in this report.

  13. In-vitro and in-vivo evaluation of repaglinide loaded floating microspheres prepared from different viscosity grades of HPMC polymer

    PubMed Central

    Sharma, Megha; Kohli, Seema; Dinda, Agnimitra

    2015-01-01

    During the study repaglinide encapsulated floating microspheres were formulated and characterized for enhancing residence time of drug in git and thereby increasing its bioavailability. Floating microspheres of ethylcellulose (EC) and hydroxypropyl methyl cellulose (HPMC) (5 and 100 cps) were prepared by emulsion solvent diffusion technique. During process optimization various parameters were studied such as: drug: polymer ratio, polymer ratio, concentration of emulsifier and stirring speed. Selected optimized formulations were studied for SEM, entrapment, floating behavior, drug release and kinetics. In-vivo floating ability (X-ray) study and in-vivo antidiabetic activity were performed on alloxan induced diabetic rats. Microspheres prepared with different viscosity grade HPMC were spherical shaped with smooth surface. Size of microspheres was in the range of 181.1–248 μm. Good entrapment and buoyancy were observed for 12 h. X-ray image showed that optimized formulation remained buoyant for more than 6 h. Optimized formulation treated group shows significant (p < 0.01) reduction in blood glucose level as compared to pure drug treated group. Repaglinide loaded floating microspheres expected to give new choice for safe, economical and increased bioavailable formulation for effective management of NIDDM. PMID:26702263

  14. In-vitro and in-vivo evaluation of repaglinide loaded floating microspheres prepared from different viscosity grades of HPMC polymer.

    PubMed

    Sharma, Megha; Kohli, Seema; Dinda, Agnimitra

    2015-11-01

    During the study repaglinide encapsulated floating microspheres were formulated and characterized for enhancing residence time of drug in git and thereby increasing its bioavailability. Floating microspheres of ethylcellulose (EC) and hydroxypropyl methyl cellulose (HPMC) (5 and 100 cps) were prepared by emulsion solvent diffusion technique. During process optimization various parameters were studied such as: drug: polymer ratio, polymer ratio, concentration of emulsifier and stirring speed. Selected optimized formulations were studied for SEM, entrapment, floating behavior, drug release and kinetics. In-vivo floating ability (X-ray) study and in-vivo antidiabetic activity were performed on alloxan induced diabetic rats. Microspheres prepared with different viscosity grade HPMC were spherical shaped with smooth surface. Size of microspheres was in the range of 181.1-248 μm. Good entrapment and buoyancy were observed for 12 h. X-ray image showed that optimized formulation remained buoyant for more than 6 h. Optimized formulation treated group shows significant (p < 0.01) reduction in blood glucose level as compared to pure drug treated group. Repaglinide loaded floating microspheres expected to give new choice for safe, economical and increased bioavailable formulation for effective management of NIDDM. PMID:26702263

  15. Effect of explosive noise on gastrointestinal transit and plasma levels of polypeptide hormones

    PubMed Central

    Mu, Zhen-Bin; Huang, Yu-Xin; Zhao, Bao-Min; Liu, Zhen-Xiong; Zhang, Bing-Hua; Wang, Qing-Li

    2006-01-01

    AIM: To investigate the effect of firing noise on gastrointestinal transit and probe its mechanism by measuring the levels of plasma polypeptide hormones. METHODS: A total of 64 SD rats were randomly divided into a control group and three stimulating groups. Firing noise of different intensity by sub-machine guns was used as inflicting factor. The effect of firing noise on liquid substance gastrointestinal transit and solid substance gastrointestinal transit was observed by measuring the ratio of carbon powder suspension transmitting and barium sticks transmitting respectively. Plasma levels of polypeptide hormones were measured by radio-immunoassay. RESULTS: The noise accelerated gastrointestinal transit of solid food by more than 80 db;and accelerated gastrointestinal transit of liquid food significantly by more than 120 db. Meantime, plasma levels of plasma motilin (MTL)(157.47±16.08; 151.90±17.08), somatostatin (SS)(513.97±88.77; 458.25±104.30), substance P (SP)(115.52±20.70; 110.28±19.96) and vasoactive intestinal peptide (VIP) (214.21±63.17; 251.76±97.24) remarkably changed also. CONCLUSION: Within a certain intensity range, the firing noise changes the levels of rat plasma gastrointestinal hormones, but the gastrointestinal transit is still normal. Beyond the range, the noise induces plasma hormone levels disturbance and gastrointestinal transit disorder. PMID:16610038

  16. Microencapsulation in genipin cross-linked gelatine-maltodextrin improves survival of Bifidobacterium adolescentis during exposure to in vitro gastrointestinal conditions.

    PubMed

    Borza, Antonela D; Annan, Nana T; Moreau, Debra L; Allan-Wojtas, Paula M; Ghanem, Amyl; Rousseau, Dérick; Paulson, Allan T; Hansen, Lisbeth Truelstrup

    2010-01-01

    To improve survival during exposure to adverse conditions, probiotic Bifidobacterium adolescentis 15703T cells were encapsulated in novel mono-core and multi-core phase-separated gelatine-maltodextrin (GMD) microspheres where the gelatine (G) phase was cross-linked with genipin (GP). Microscopy showed that encapsulated cells were exclusively associated with maltodextrin (MD) core(s). Small (average diameter 37 microm) and large (70 microm) GMD and G microspheres were produced by modulating factors (e.g. mixing speed, surfactant, GP and G concentrations) affecting the size, structural stability and phase-separation. In vitro sequential gastro-intestinal (GI) juice challenge experiments revealed increased survival of cells encapsulated in GMD ( approximately 10(6-7) cfu mL(-1)) and G (approximately 10(5) cfu mL(-1)) microspheres as compared to free cells (approximately 10(4) cfu mL(-1)). In GMD microspheres, the bacteria derive energy from MD to survive during exposure to acid and bile salts. In conclusion, the novel food grade GMD microencapsulation formulation was shown to protect probiotic bifidobacteria from adverse conditions. PMID:19860547

  17. Gastrointestinal Stromal Tumors: A Case Report

    PubMed Central

    Sashidharan, Palankezhe; Matele, Apoorva; Matele, Usha; Al Felahi, Nowfel; Kassem, Khalid F.

    2014-01-01

    Advances in the identification of gastrointestinal stromal tumors, its molecular and immunohiostochemical basis, and its management have been a watershed in the treatment of gastrointestinal tumors. This paradigm shift occurred over the last two decades and gastrointestinal stromal tumors have now come to be understood as rare gastrointestinal tract tumors with predictable behavior and outcome, replacing the older terminologies like leiomyoma, schwannoma or leiomyosarcoma. This report presents a case of gastric gastrointestinal stromal tumor operated recently in a 47-year-old female patient and the outcome, as well as literature review of the pathological identification, sites of origin, and factors predicting its behavior, prognosis and treatment. PMID:24715944

  18. Silicon microspheres for near-IR communication applications

    NASA Astrophysics Data System (ADS)

    Serpengüzel, Ali; Demir, Abdullah

    2008-06-01

    We have performed transverse electric and transverse magnetic polarized elastic light scattering calculations at 90° and 0° in the o-band at 1.3 µm for a 15 µm radius silicon microsphere with a refractive index of 3.5. The quality factors are on the order of 107 and the mode/channel spacing is 7 nm, which correlate well with the refractive index and the optical size of the microsphere. The 90° elastic light scattering can be used to monitor a dropped channel (drop port), whereas the 0° elastic scattering can be used to monitor the transmission channel (through port). The optical resonances of the silicon microspheres provide the necessary narrow linewidths that are needed for high-resolution optical communication applications. Potential telecommunication applications include filters, modulators, switches, wavelength converters, detectors, amplifiers and light sources. Silicon microspheres show promise as potential building blocks for silicon-based electrophotonic integration.

  19. Super-focusing of center-covered engineered microsphere.

    PubMed

    Wu, Mengxue; Chen, Rui; Soh, Jiahao; Shen, Yue; Jiao, Lishi; Wu, Jianfeng; Chen, Xudong; Ji, Rong; Hong, Minghui

    2016-01-01

    Engineered microsphere possesses the advantage of strong light manipulation at sub-wavelength scale and emerges as a promising candidate to shrink the focal spot size. Here we demonstrated a center-covered engineered microsphere which can adjust the transverse component of the incident beam and achieve a sharp photonic nanojet. Modification of the beam width and working distance of the photonic nanojet were achieved by tuning the cover ratio of the engineered microsphere, leading to a sharp spot size which exceeded the optical diffraction limit. At a wavelength of 633 nm, a focal spot of 245 nm (0.387 λ) was achieved experimentally under plane wave illumination. Strong localized field with Bessel-like distribution was demonstrated by employing the linearly polarized beam and a center-covered mask being engineered on the microsphere. PMID:27528093

  20. BIOCOMPATIBLE FLUORESCENT MICROSPHERES: SAFE PARTICLES FOR MATERIAL PENETRATION STUDIES

    SciTech Connect

    Farquar, G; Leif, R

    2009-07-15

    Biocompatible polymers with hydrolyzable chemical bonds have been used to produce safe, non-toxic fluorescent microspheres for material penetration studies. The selection of polymeric materials depends on both biocompatibility and processability, with tailored fluorescent properties depending on specific applications. Microspheres are composed of USFDA-approved biodegradable polymers and non-toxic fluorophores and are therefore suitable for tests where human exposure is possible. Micropheres were produced which contain unique fluorophores to enable discrimination from background aerosol particles. Characteristics that affect dispersion and adhesion can be modified depending on use. Several different microsphere preparation methods are possible, including the use of a vibrating orifice aerosol generator (VOAG), a Sono-Tek atomizer, an emulsion technique, and inkjet printhead. Applications for the fluorescent microspheres include challenges for biodefense system testing, calibrants for biofluorescence sensors, and particles for air dispersion model validation studies.

  1. Preparation of microspheres by an emulsification-complexation method.

    PubMed

    Kim, Jin-Chul; Song, Myeong-Eun; Lee, Eun-Joo; Park, Seung-Kyu; Rang, Moon-Jeong; Ahn, Ho-Jeong

    2002-04-01

    Microspheres were prepared by complexation of a cationic polymer, polyquaternium-24, and an anionic surfactant, sodium lauryl sulfate (SLS). The cationic polymer solution was emulsified in dimethylsiloxane to give water in silicone emulsion (W/Si), and it was used as a template for the formation of microspheres. The emulsion was dispersed into the SLS solution. In this process, two kinds of droplets, silicone dropletes and microspheres composed of the cationic polymer and SLS, were formed, evidenced by X-ray energy dispersive spectra. The mean diameter of the microspheres was reduced from 105.7 to 64.8 mum as the stirring rate for W/Si preparation increased from 300 to 1000 rpm. It is believed that water droplets in W/Si emulsion, when exposed to SLS solution, could be solidified by the complexation of the cationic polymer and the anionic surfactant. PMID:16290495

  2. Amorphous and nanostructured silica and aluminosilicate spray-dried microspheres

    NASA Astrophysics Data System (ADS)

    Todea, M.; Turcu, R. V. F.; Frentiu, B.; Tamasan, M.; Mocuta, H.; Ponta, O.; Simon, S.

    2011-08-01

    Amorphous silica and aluminosilicate microspheres with diameters in the 0.1-20 μm range were produced by spray drying method. SEM, TEM and AFM images showed the spherical shape of the obtained particles. Based on thermal analysis data, several heat treatments have been applied on the as-prepared samples in order to check the amorphous state stability of the microspheres and to develop nanosized crystalline phases. As-prepared microspheres remain amorphous up to 1400 °C. By calcination at 1400 °C, cristobalite type nanocrystals are developed on silica sample, while in aluminosilicate sample first are developed mullite type nanocrystals and only after prolonged treatment are developed also cristobalite type nanocrystals. 29Si and 27Al MAS NMR results show that the local order around aluminum and silicon atoms strongly depend on the thermal history of the microspheres.

  3. Properties and applications of a pitch carbon microsphere composite

    NASA Technical Reports Server (NTRS)

    Price, H. L.; Nelson, J. B.

    1977-01-01

    Some properties and applications of a pitch carbon microsphere composite are described. The small hollow microspheres are made from the pitch which is usually a wasted by-product of petroleum refining. In contrast to high density composites or syntactic foams in which microspheres are inclusions within a continuous matrix, this composite is an aggregate of microspheres bonded together by a small amount of thermosetting polymer which does not form a continuous matrix. The result is a composite with low density and thermal expansion, modest strength and rigidity, and high porosity and carbon content. Mechanical, thermal, and sorption properties have been measured. Applications of the composite include honeycomb filler for high temperature or ionizing radiation fields and a wicking absorber for solar-powered stills.

  4. Super-focusing of center-covered engineered microsphere

    PubMed Central

    Wu, Mengxue; Chen, Rui; Soh, Jiahao; Shen, Yue; Jiao, Lishi; Wu, Jianfeng; Chen, Xudong; Ji, Rong; Hong, Minghui

    2016-01-01

    Engineered microsphere possesses the advantage of strong light manipulation at sub-wavelength scale and emerges as a promising candidate to shrink the focal spot size. Here we demonstrated a center-covered engineered microsphere which can adjust the transverse component of the incident beam and achieve a sharp photonic nanojet. Modification of the beam width and working distance of the photonic nanojet were achieved by tuning the cover ratio of the engineered microsphere, leading to a sharp spot size which exceeded the optical diffraction limit. At a wavelength of 633 nm, a focal spot of 245 nm (0.387 λ) was achieved experimentally under plane wave illumination. Strong localized field with Bessel-like distribution was demonstrated by employing the linearly polarized beam and a center-covered mask being engineered on the microsphere. PMID:27528093

  5. Polycrystalline metasurface perfect absorbers fabricated using microsphere photolithography.

    PubMed

    Qu, Chuang; Kinzel, Edward C

    2016-08-01

    Microsphere photolithography (MPL) is a practical, cost-effective nanofabrication technique. It uses self-assembled microspheres in contact with the photoresist as microlenses. The microspheres focus incident light to a sub-diffraction limited array of photonic jets in the photoresist. This Letter explores the MPL technique to pattern metal-insulator-metal metasurfaces with near-perfect absorption at mid-wave infrared (MWIR) frequencies. Experimental results are compared to electromagnetic simulations of both the exposure process and the metasurface response. The microsphere self-assembly technique results in a polycrystalline metasurface; however, the metal-insulator-metal structure is shown to be defect tolerant. While the MPL approach imposes geometric constraints on the metasurface design, once understood, the technique can be used to create functional devices. In particular, the ability to tune the resonant wavelength with the exposure dose raises the potential of hierarchical structures. PMID:27472578

  6. Physicochemical characteristics of magnetic microspheres containing tissue plasminogen activator

    NASA Astrophysics Data System (ADS)

    Xie, Yumei; Kaminski, Michael D.; Torno, Michael D.; Finck, Martha R.; Liu, Xianqiao; Rosengart, Axel J.

    2007-04-01

    As a first step toward improving the treatment of stroke, we are developing a magnetic carrier system to target tissue plasminogen activator (tPA) to a thrombosis. We report the characterization of biodegradable microspheres containing tPA and magnetic iron oxide. The resultant microspheres were superparamagnetic with a magnetization of 6.9-8.7 emu/g. We encapsulated 5% tPA by mass which eluted from the microspheres to produce a solution concentration of 5.3- 19.6 μg/mL in tPA, which exceeds the theoretical thrombolysis concentration. Although smaller microspheres will be necessary for in vivo experiments, we have shown that sufficient tPA can be encapsulated and released in a magnetic matrix.

  7. An Improvement of the Efficacy of Moxifloxacin HCl for the Treatment of Bacterial Keratitis by the Formulation of Ocular Mucoadhesive Microspheres

    PubMed Central

    Dandagi, Panchaxari Mallappa; Belekar, Amit Manohar; Mastiholimath, Vinayak Shivamurthy; Gadad, Anand Panchakshari; Sontake, Vivek Wamanrao; Salian, Prashant Sanjivrao

    2013-01-01

    The aim of this study was to prepare novel ocular mucoadhesive microspheres of Moxifloxacin HCl to increase its residence time on the ocular surface and to enhance its therapeutic efficacy in ocular bacterial keratitis. Microspheres were fabricated with different grades of Methocel and Sodium CMC as polymers. Microspheres were evaluated for their particle size, morphology, encapsulation efficiency, mucoadhesion, antimicrobial efficacy, and in vitro drug release studies. In vivo studies were carried out for the promising formulation on eyes of albino rabbits by inducing bacterial keratitis. A sterile microspheres suspension in light mineral oil was applied to infected eyes twice a day. A marketed conventional eye drop was used as a positive control. Eyes were examined daily for improvement of clinical signs of bacterial keratitis by an ophthalmologist. The average particle size of microspheres was found to be less than 80 μm. Methocel microspheres were found to have a smoother surface than Sodium CMC. Entrapment efficiency was enhanced with an increased polymer concentration and viscosity. The formulation containing Methocel K100M with a drug: polymer ratio of 1:2 exerted longer corneal and conjunctival mucoadhesion time of 8.45±0.15 h and 9.40±0.53 h respectively. In vitro release of Moxifloxacin HCl from microspheres was retarded with increased viscosity and concentration of polymers, and was controlled by diffusion as well as polymer relaxation. All formulations showed comparable antimicrobial activity in comparison with conventional marketed eye drops. The formulation containing Methocel K100M with a drug: polymer ratio of 1:2 was found to be a promising formulation and was used for the in vivo studies. The in vivo studies revealed that microspheres demonstrated significantly lower clinical scores and reduced the total duration of therapy than the marketed Moxifloxacin HCl eye drops. In vitro and in vivo studies showed that ocular mucoadhesive microspheres of

  8. An Improvement of the Efficacy of Moxifloxacin HCl for the Treatment of Bacterial Keratitis by the Formulation of Ocular Mucoadhesive Microspheres.

    PubMed

    Dandagi, Panchaxari Mallappa; Belekar, Amit Manohar; Mastiholimath, Vinayak Shivamurthy; Gadad, Anand Panchakshari; Sontake, Vivek Wamanrao; Salian, Prashant Sanjivrao

    2013-03-01

    The aim of this study was to prepare novel ocular mucoadhesive microspheres of Moxifloxacin HCl to increase its residence time on the ocular surface and to enhance its therapeutic efficacy in ocular bacterial keratitis. Microspheres were fabricated with different grades of Methocel and Sodium CMC as polymers. Microspheres were evaluated for their particle size, morphology, encapsulation efficiency, mucoadhesion, antimicrobial efficacy, and in vitro drug release studies. In vivo studies were carried out for the promising formulation on eyes of albino rabbits by inducing bacterial keratitis. A sterile microspheres suspension in light mineral oil was applied to infected eyes twice a day. A marketed conventional eye drop was used as a positive control. Eyes were examined daily for improvement of clinical signs of bacterial keratitis by an ophthalmologist. The average particle size of microspheres was found to be less than 80 μm. Methocel microspheres were found to have a smoother surface than Sodium CMC. Entrapment efficiency was enhanced with an increased polymer concentration and viscosity. The formulation containing Methocel K100M with a drug: polymer ratio of 1:2 exerted longer corneal and conjunctival mucoadhesion time of 8.45±0.15 h and 9.40±0.53 h respectively. In vitro release of Moxifloxacin HCl from microspheres was retarded with increased viscosity and concentration of polymers, and was controlled by diffusion as well as polymer relaxation. All formulations showed comparable antimicrobial activity in comparison with conventional marketed eye drops. The formulation containing Methocel K100M with a drug: polymer ratio of 1:2 was found to be a promising formulation and was used for the in vivo studies. The in vivo studies revealed that microspheres demonstrated significantly lower clinical scores and reduced the total duration of therapy than the marketed Moxifloxacin HCl eye drops. In vitro and in vivo studies showed that ocular mucoadhesive microspheres of

  9. Structural resonances in the Raman spectrum of glass microsphere

    NASA Astrophysics Data System (ADS)

    Wang, Ji-You; Xu, Xiao xuan; Zhang, Cun zhou

    2000-10-01

    Structural resonances have been found in the Raman spectrum of an optically levitated TiBa glass microsphere. The observed resonances could be assigned by using the well-known Lorenz-Mie Formalism. It was found that the diameter of the TiBa glass microsphere is 24.490micrometers , and the refractive index of TiBa glass is 1.895 at about 645nm.

  10. ENCAPSULATION OF PALLADIUM IN POROUS WALL HOLLOW GLASS MICROSPHERES

    SciTech Connect

    Heung, L; George Wicks, G; Ray Schumacher, R

    2008-04-09

    A new encapsulation method was investigated in an attempt to develop an improved palladium packing material for hydrogen isotope separation. Porous wall hollow glass microspheres (PWHGMs) were produced by using a flame former, heat treating and acid leaching. The PWHGMs were then filled with palladium salt using a soak-and-dry process. The palladium salt was reduced at high temperature to leave palladium inside the microspheres.

  11. X- And y-axis driver for rotating microspheres

    DOEpatents

    Weinstein, Berthold W.

    1979-01-01

    Apparatus for precise control of the motion and position of microspheres for examination of their interior and/or exterior. The apparatus includes an x- and y-axis driver mechanism controlled, for example, by a minicomputer for selectively rotating microspheres retained between a pair of manipulator arms having flat, smooth end surfaces. The driver mechanism includes an apertured plate and ball arrangement which provided for coupled equal and opposite movement of the manipulator arms in two perpendicular directions.

  12. A novel method for producing microspheres with semipermeable polymer membranes

    NASA Technical Reports Server (NTRS)

    Lin, K. C.; Wang, Taylor G.

    1992-01-01

    A new and systematic approach for producing polymer microspheres has been demonstrated. The membrane of the microsphere is formed by immersing the polyanionic droplet into a collapsing annular sheet, which is made of another polycation polymer solution. This method minimizes the impact force during the time when the chemical reaction takes place, hence eliminating the shortcomings of the current encapsulation techniques. The results of this study show the feasibility of this method for mass production of microcapsules.

  13. Characterization of Fluorescent Polystyrene Microspheres for Advanced Flow Diagnostics

    NASA Technical Reports Server (NTRS)

    Maisto, Pietro M. F.; Lowe, K. Todd; Byun, Guibo; Simpson, Roger; Vercamp, Max; Danley, Jason E.; Koh, Brian; Tiemsin, Pacita; Danehy, Paul M.; Wohl, Christopher J.

    2013-01-01

    Fluorescent dye-doped polystyrene latex microspheres (PSLs) are being developed for velocimetry and scalar measurements in variable property flows. Two organic dyes, Rhodamine B (RhB) and dichlorofluorescence (DCF), are examined to assess laser-induced fluorescence (LIF) properties for flow imaging applications and single-shot temperature measurements. A major interest in the current research is the application of safe dyes, thus DCF is of particular interest, while RhB is used as a benchmark. Success is demonstrated for single-point laser Doppler velocimetry (LDV) and also imaging fluorescence, excited via a continuous wave 2 W laser beam, for exposures down to 10 ms. In contrast, when exciting with a pulsed Nd:YAG laser at 200 mJ/pulse, no fluorescence was detected, even when integrating tens of pulses. We show that this is due to saturation of the LIF signal at relatively low excitation intensities, 4-5 orders of magnitude lower than the pulsed laser intensity. A two-band LIF technique is applied in a heated jet, indicating that the technique effectively removes interfering inputs such as particle diameter variation. Temperature measurement uncertainties are estimated based upon the variance measured for the two-band LIF intensity ratio and the achievable dye temperature sensitivity, indicating that particles developed to date may provide about +/-12.5 C precision, while future improvements in dye temperature sensitivity and signal quality may enable single-shot temperature measurements with sub-degree precision.

  14. Advances in upper gastrointestinal endoscopy

    PubMed Central

    Graham, David G.; Banks, Matthew R.

    2015-01-01

    The rapidly moving technological advances in gastrointestinal endoscopy have enhanced an endoscopist’s ability to diagnose and treat lesions within the gastrointestinal tract. The improvement in image quality created by the advent of high-definition and magnification endoscopy, alongside image enhancement, produces images of superb quality and detail that empower the endoscopist to identify important lesions that have previously been undetectable. Additionally, we are now seeing technologies emerge, such as optical coherence tomography and confocal laser endomicroscopy, that allow the endoscopist to visualize individual cells on a microscopic level and provide a real time, in vivo histological assessment. Within this article we discuss these technologies, as well as some of the results from their early use in clinical studies. PMID:26918137

  15. Collective interaction of microscale matters in natural analogy: human cancer cells vs. microspheres

    NASA Astrophysics Data System (ADS)

    Ahn, Sungsook; Lee, Sang Joon; Postech Team

    2014-11-01

    Collective behaviors have been considered both in living and lifeless things as a natural phenomenon. During the ordering process, a sudden and spontaneous transition is typically generated between an order and a disorder according to the population density of interacting elements. In a cellular level collective behavior, the cells are distributed in the characteristic patterns according to the population density and the mutual interaction of the individual cells undergo density-dependent diffusive motion. On the other hand, density-controlled surface-modified hollow microsphere suspension induces an overpopulation via buoyancy which provides a driving force to induce an assembly. The collective behaviors of the cells and microspheres in a designed liquid medium are explained in terms of the deviation from the interparticle distance distribution and the induced strength to organize the particle position in a specific distance range. as a result, microscale particulate matters exhibit high resemblance in their pair correlation and dynamical heterogeneity in the intermediate range between a single individual and an agglomerate. Therefore, it is suggested that biological systems are analogically explained to be dominated by physically interactive aspects.

  16. Upper gastrointestinal physiology and diseases.

    PubMed

    Waldum, Helge L; Kleveland, Per M; Fossmark, Reidar

    2015-06-01

    Nordic research on physiology and pathophysiology of the upper gastrointestinal tract has flourished during the last 50 years. Swedish surgeons and physiologists were in the frontline of research on the regulation of gastric acid secretion. This research finally led to the development of omeprazole, the first proton pump inhibitor. When Swedish physiologists developed methods allowing the assessment of acid secretion in isolated oxyntic glands and isolated parietal cells, the understanding of mechanisms by which gastric acid secretion is regulated took a great step forward. Similarly, in Trondheim, Norway, the acid producing isolated rat stomach model combined with a sensitive and specific method for determination of histamine made it possible to evaluate this regulation qualitatively as well as quantitatively. In Lund, Sweden, the identification of the enterochromaffin-like cell as the cell taking part in the regulation of acid secretion by producing and releasing histamine was of fundamental importance both physiologically and clinically. Jorpes and Mutt established a center at Karolinska Institutet in Stockholm for the purification of gastrointestinal hormones in the 1960s, and Danes followed up this work by excelling in the field of determination and assessment of biological role of gastrointestinal hormones. A Finnish group was for a long period in the forefront of research on gastritis, and the authors' own studies on the classification of gastric cancer and the role of gastrin in the development of gastric neoplasia are of importance. It can, accordingly, be concluded that Nordic researchers have been central in the research on area of the upper gastrointestinal physiology and diseases. PMID:25857514

  17. Gastrointestinal endoscopy: infection and disinfection.

    PubMed Central

    O'Connor, H J; Axon, A T

    1983-01-01

    The past decade has seen the development of an array of complex flexible fibreoptic instruments for gastrointestinal (GI) endoscopy, and an increasing use of these for diagnostic and therapeutic purposes. It has been recognised more recently that the use of contaminated endoscopic equipment can lead to serious and occasionally fatal infections. Infection with a wide variety of micro-organisms has been reported following oesophago-gastroduodenoscopy (OGD) and endoscopic retrograde cholangio-pancreatography (ERCP). PMID:6414894

  18. Abiogenic photophosphorylation of ADP to ATP sensitized by flavoproteinoid microspheres.

    PubMed

    Kolesnikov, Michael P; Telegina, Taisiya A; Lyudnikova, Tamara A; Kritsky, Mikhail S

    2008-06-01

    A model for abiogenic photophosphorylation of ADP by orthophosphate to yield ATP was studied. The model is based on the photochemical activity of flavoproteinoid microspheres that are formed by aggregation in an aqueous medium of products of thermal condensation of a glutamic acid, glycine and lysine mixture (8:3:1) and contain, along with amino acid polymers (proteinoids), abiogenic isoalloxazine (flavin) pigments. Irradiation of aqueous suspensions of microspheres with blue visible light or ultraviolet in the presence of ADP and orthophosphate resulted in ATP formation. The yield of ATP in aerated suspensions was 10-20% per one mol of starting ADP. Deaeration reduced the photophosphorylating activity of microspheres five to 10 times. Treatment of aerated microsphere suspensions with superoxide dismutase during irradiation partially suppressed ATP formation. Deaerated microspheres restored completely their photophosphorylating activity after addition of hydrogen peroxide to the suspension. The photophosphorylating activity of deaerated suspensions of flavoproteinoid microspheres was also recovered by introduction of Fe3+-cytochrome c, an electron acceptor alternative to oxygen. On the basis of the results obtained, a chemical mechanism of phosphorylation is proposed in which the free radical form of reduced flavin sensitizer (F1H*) and ADP are involved. PMID:18386156

  19. Drug encapsulated aerosolized microspheres as a biodegradable, intelligent glioma therapy.

    PubMed

    Floyd, J Alaina; Galperin, Anna; Ratner, Buddy D

    2016-02-01

    The grim prognosis for patients diagnosed with malignant gliomas necessitates the development of new therapeutic strategies for localized and sustained drug delivery to combat tumor drug resistance and regrowth. Here we introduce drug encapsulated aerosolized microspheres as a biodegradable, intelligent glioma therapy (DREAM BIG therapy). DREAM BIG therapy is envisioned to deliver three chemotherapeutics, temporally staged over one year, via a bioadhesive, biodegradable spray directly to the brain surgical site after tumor excision. In this proof-of-principle article exploring key components of the DREAM BIG therapy prototype, rhodamine B (RB) encapsulated poly(lactic-co-glycolic acid) and immunoglobulin G (IgG) encapsulated poly(lactic acid) microspheres were formulated and characterized. The encapsulation efficiency of RB and IgG and the release kinetics of the model drugs from the microspheres were elucidated in addition to the release kinetics of RB from poly(lactic-co-glycolic acid) microspheres formulated in a degradable poly(N-isopropylacrylamide) solution. The successful aerosolized application onto brain tissue ex-vivo demonstrated the conformal adhesion of the RB encapsulated poly(lactic-co-glycolic acid) microspheres to the convoluted brain surface mediated by the thermoresponsive carrier, poly(N-isopropylacrylamide). These preliminary results suggest the potential of the DREAM BIG therapy for future use with multiple chemotherapeutics and microsphere types to combat gliomas at a localized site. PMID:26238392

  20. Alcohol and gastrointestinal bleeding.

    PubMed

    MacMath, T L

    1990-11-01

    Ethanol has experimentally been shown to be "ulcerogenic," independent of gastric intraluminal pH. Ethanol remains ulcerogenic despite antisecretory doses of H2-receptor antagonists. Low-dose alcohol stimulates acid secretion in man, an effect possibly mediated by histamine or gastrin. High-dose alcohol reduces intraluminal acid by damaging mucosa, thereby enhancing back diffusion of hydrogen ion, and also by direct damage to oxyntic (parietal) cells. Ethanol is capable of increasing gastric mucosal permeability as evidenced by the increase in back diffusion (increases intraluminal pH) and by the characteristic fall in transmucosal potential difference which reflects surface cell layer exfoliation. This exfoliation may offer an explanation for the potentiating effect of alcohol on gastric mucosal injury when it is ingested simultaneously with other gastric irritants. Ethanol of greater than 20% concentration can rapidly destroy the gastric mucus-bicarbonate layer, which may be a defense layer for both the inhibition of back diffusion and bicarbonate neutralization of existing acid. Ethanol depletes sulfhydryl compounds in gastric mucosa. These sulfhydryls may be necessary for stabilization of cell membranes as well as for binding free radicals. Ethanol is damaging to the mucosal microcirculation. The rapidity of ethanol-induced damage makes it unlikely that the process is purely ischemic. The cytoprotective phenomenon, as this brief literature review suggests, is a multifactorial, dynamic process. The complex interplay of mucosal defense factors, endogenous and exogenous stimuli, induction of humoral responses, and ultimately the success or failure of cellular repair, is unlikely to be solely mediated by endogenous prostaglandins. Although prostaglandins are unquestionably significant to cytoprotection, the supporting and, perhaps, major roles of leukotrienes, sulfhydryls, histamines, and like substances cannot be ignored. Several innovative therapeutic agents

  1. Allergy and the gastrointestinal system.

    PubMed

    Vighi, G; Marcucci, F; Sensi, L; Di Cara, G; Frati, F

    2008-09-01

    The gastrointestinal system plays a central role in immune system homeostasis. It is the main route of contact with the external environment and is overloaded every day with external stimuli, sometimes dangerous as pathogens (bacteria, protozoa, fungi, viruses) or toxic substances, in other cases very useful as food or commensal flora. The crucial position of the gastrointestinal system is testified by the huge amount of immune cells that reside within it. Indeed, gut-associated lymphoid tissue (GALT) is the prominent part of mucosal-associated lymphoid tissue (MALT) and represents almost 70% of the entire immune system; moreover, about 80% of plasma cells [mainly immunoglobulin A (IgA)-bearing cells] reside in GALT. GALT interacts strictly with gastrointestinal functions in a dynamic manner; for instance, by increasing intestinal permeability in replay to particular stimulations, or orientating the immune response towards luminal content, allowing either tolerance or elimination/degradation of luminal antigens, or sometimes provoking damage to the intestinal mucosa, such as in coeliac disease or food allergy. The immune mechanisms implicated in these actions are very complex and belong to both innate and adaptive immunity; innate immunity supplies an immediate non-specific response that is indispensable before specific adaptive immunity, which needs 7-10 days to be efficacious, takes place. The results of their interactions depend upon different contexts in which contact with external agents occurs and may change according to different genetic settings of the hosts. PMID:18721321

  2. Diet and Upper Gastrointestinal Malignancies

    PubMed Central

    Abnet, Christian C.; Corley, Douglas A.; Freedman, Neal D.; Kamangar, Farin

    2015-01-01

    Diet is believed to modulate cancer risk and this relationship has been widely studied in the gastrointestinal tract. Observational epidemiologic studies have provided most of the evidence for the effects of diet on cancer risk, because clinical trials to determine nutritional exposures are often impossible, impractical, or unaffordable. Although a few foods or nutrients are thought to protect against specific types of cancer, it seems clear that the strength and even direction of dietary associations (increasing or decreasing risk) is organ site- and even histology-specific, along the gastrointestinal tract. Although some hypotheses are supported by a substantial body of observational data (drinking hot maté contributes to esophageal cancer), there is not much data to support others. We discuss some highly touted hypotheses and draw interim conclusions about what is known, and what could be done to improve the level of evidence. The complex nature of diet and its associations can be productively investigated with disease-specific studies. However, public health recommendations for normal-risk individuals regarding diet and gastrointestinal cancer should probably emphasize the importance of eating for overall health, rather than eating specific foods to reduce risk for specific cancers. PMID:25680671

  3. Gastrointestinal absorption of metallic mercury.

    PubMed

    Sandborgh-Englund, Gunilla; Einarsson, Curt; Sandström, Magnus; Ekstrand, Jan

    2004-09-01

    The absorption of mercury from the gastrointestinal systems of 7 subjects, of whom none had any amalgam fillings, was examined in this study. The authors obtained quantitative information about mercury concentration in plasma and duodenal fluid after the gastrointestinal systems of the subjects were exposed to liquid elemental mercury enclosed in rubber balloons (i.e., approximately 20 g of mercury), using a standard procedure followed for the sampling of bile. Plasma samples were collected prior to exposure, as well as up to 10 d following exposure, and duodenal fluid was collected 1 h, 2 h, 4 h, and 6 h during the intubation process. The authors studied the kinetics of dissolution in vitro by leaching elemental liquid mercury and mercuric chloride. The results of this study supported the hypothesis that metallic mercury is oxidized in the gastrointestinal tract. In addition, the authors determined that duodenal intubation, while using liquid metallic mercury in rubber bags, resulted in the diffusion of minor amounts of atomic elemental mercury through the rubber walls. The absorbed amount of mercury that reached the central circulation was comparable to a daily dose of mercury from dental amalgam in the amalgam-bearing population. PMID:16381485

  4. Microspheres and Nanotechnology for Drug Delivery.

    PubMed

    Jóhannesson, Gauti; Stefánsson, Einar; Loftsson, Thorsteinn

    2016-01-01

    Ocular drug delivery to the posterior segment of the eye can be accomplished by invasive drug injections into different tissues of the eye and noninvasive topical treatment. Invasive treatment involves the risks of surgical trauma and infection, and conventional topical treatments are ineffective in delivering drugs to the posterior segment of the eye. In recent years, nanotechnology has become an ever-increasing part of ocular drug delivery. In the following, we briefly review microspheres and nanotechnology for drug delivery to the eye, including different forms of nanotechnology such as nanoparticles, microparticles, liposomes, microemulsions and micromachines. The permeation barriers and anatomical considerations linked to ocular drug delivery are discussed and a theoretical overview on drug delivery through biological membranes is given. Finally, in vitro, in vivo and human studies of x03B3;-cyclodextrin nanoparticle eyedrop suspensions are discussed as an example of nanotechnology used for drug delivery to the eye. PMID:26501994

  5. Permeability of Hollow Microspherical Membranes to Helium

    NASA Astrophysics Data System (ADS)

    Zinoviev, V. N.; Kazanin, I. V.; Pak, A. Yu.; Vereshchagin, A. S.; Lebiga, V. A.; Fomin, V. M.

    2016-01-01

    This work is devoted to the study of the sorption characteristics of various hollow microspherical membranes to reveal particles most suitable for application in the membrane-sorption technologies of helium extraction from a natural gas. The permeability of the investigated sorbents to helium and their impermeability to air and methane are shown experimentally. The sorption-desorption dependences of the studied sorbents have been obtained, from which the parameters of their specific permeability to helium are calculated. It has been established that the physicochemical modification of the original particles exerts a great influence on the coefficient of the permeability of a sorbent to helium. Specially treated cenospheres have displayed high efficiency as membranes for selective extraction of helium.

  6. Site and mechanism of morphine tolerance in the gastrointestinal tract

    PubMed Central

    AKBARALI, H. I.; INKISAR, A.; DEWEY, W. L.

    2015-01-01

    Opioid-induced constipation is a major clinical problem. The effects of morphine, and other narcotics, on the gastrointestinal tract persist over long-term use thus limiting the clinical benefit of these excellent pain relievers. The effects of opioids in the gut, including morphine, are largely mediated by the μ-opioid receptors at the soma and nerve terminals of enteric neurons. Recent studies demonstrate that regional differences exist in both acute and chronic morphine along the gastrointestinal tract. While tolerance develops to the analgesic effects and upper gastrointestinal motility upon repeated morphine administration, tolerance does not develop in the colon with chronic opioids resulting in persistent constipation. Here, we review the mechanisms by which tolerance develops in the small but not the large intestine. The regional differences lie in the signaling and regulation of the μopioid receptor in the various segments of the gastrointestinal tract. The differential role of β-arrestin2 in tolerance development between central and enteric neurons defines the potential for therapeutic approaches in developing ligands with analgesic properties and minimal constipating effects. PMID:25257923

  7. Allergic gastrointestinal motility disorders in infancy and early childhood.

    PubMed

    Heine, Ralf G

    2008-08-01

    Gastro-oesophageal reflux disease, constipation and colic are among the most common disorders in infancy and early childhood. In at least a subset of infants with these functional disorders, improvement after dietary elimination of specific food proteins has been demonstrated. Gastrointestinal food allergy should therefore be considered in the differential diagnosis of infants presenting with persistent regurgitation, constipation or irritable behaviour, particularly if conventional treatment has not been beneficial. The diagnosis of food protein-induced gastrointestinal motility disorders is hampered by the absence of specific clinical features or useful laboratory markers. Gastrointestinal biopsies before commencing a hypoallergenic diet may provide the most important diagnostic clues. Early recognition is essential for the optimal management of these patients to prevent nutritional sequelae or aversive feeding behaviours. Treatment relies on hypoallergenic formulae, as well as maternal elimination diets in breast-fed infants. Further research is required to better define the pathological mechanisms and diagnostic markers of paediatric allergic gastrointestinal motility disorders. The following article will present three instructive cases followed by discussion of the clinical presentation, diagnosis, treatment and natural history of food allergic motility disorders in infancy and early childhood. PMID:18713339

  8. Histamine H4 receptors in the gastrointestinal tract

    PubMed Central

    Deiteren, A; De Man, J G; Pelckmans, P A; De Winter, B Y

    2015-01-01

    Histamine is a well-established mediator involved in a variety of physiological and pathophysiological mechanisms and exerts its effect through activation of four histamine receptors (H1–H4). The histamine H4 receptor is the newest member of this histamine receptor family, and is expressed throughout the gastrointestinal tract as well as in the liver, pancreas and bile ducts. Functional studies using a combination of selective and non-selective H4 receptor ligands have rapidly increased our knowledge of H4 receptor involvement in gastrointestinal processes both under physiological conditions and in models of disease. Strong evidence points towards a role for H4 receptors in the modulation of immune-mediated responses in gut inflammation such as in colitis, ischaemia/reperfusion injury, radiation-induced enteropathy and allergic gut reactions. In addition, data have emerged implicating H4 receptors in gastrointestinal cancerogenesis, sensory signalling, and visceral pain as well as in gastric ulceration. These studies highlight the potential of H4 receptor targeted therapy in the treatment of various gastrointestinal disorders such as inflammatory bowel disease, irritable bowel syndrome and cancer. PMID:25363289

  9. Protective role of Hemeoxygenase-1 in Gastrointestinal Diseases

    PubMed Central

    Chang, Marisol; Xue, Jing; Sharma, Vishal; Habtezion, Aida

    2014-01-01

    Disorders and diseases of the gastrointestinal system encompass a wide array of pathogenic mechanisms as a result of genetic, infectious, neoplastic, and inflammatory conditions. Inflammatory diseases in general are rising in incidence and are emerging clinical problems in gastroenterology and hepatology. Hemeoxygenase-1 (HO-1) is a stress-inducible enzyme that has been shown to confer protection in various organ-system models. Its downstream effectors, carbon monoxide and biliverdin have also been shown to offer these beneficial effects. Many studies suggest that induction of HO-1 expression in gastrointestinal tissues and cells plays a critical role in cytoprotection and resolving inflammation as well as tissue injury. In this review we examine the protective role of HO-1 and its downstream effectors in modulating inflammatory diseases of the upper (esophagus and stomach) and lower (small and large intestine) gastrointestinal tract, the liver, and the pancreas. Cytoprotective, anti-inflammatory, anti-proliferative, anti-oxidant, and anti-apoptotic activities of HO-1 make it a promising if not ideal therapeutic target for inflammatory diseases of the gastrointestinal system. PMID:25428780

  10. Microsphere size influences the foreign body reaction.

    PubMed

    Zandstra, J; Hiemstra, C; Petersen, A H; Zuidema, J; van Beuge, M M; Rodriguez, S; Lathuile, A A; Veldhuis, G J; Steendam, R; Bank, R A; Popa, E R

    2014-01-01

    Biodegradable poly-(DL-lactide-co-glycolide) (PLGA) microspheres (MSP) are attractive candidate vehicles for site-specific or systemic sustained release of therapeutic compounds. This release may be altered by the host's foreign body reaction (FBR), which is dependent on the characteristics of the implant, e.g. chemistry, shape or size. In this study, we focused on the characterisation of the influence of MSP size on the FBR. To this end we injected monodisperse MSP of defined size (small 5.8 µm, coefficient of variance (CV) 14 % and large 29.8 µm, CV 4 %) and polydisperse MSP (average diameter 34.1 µm, CV 51 %) under the skin of rats. MSP implants were retrieved at day 7, 14 and 28 after transplantation. The FBR was studied in terms of macrophage infiltration, implant encapsulation, vascularisation and extracellular matrix deposition. Although PLGA MSP of all different sizes demonstrated excellent in vitro and in vivo biocompatibility, significant differences were found in the characteristics of the FBR. Small MSP were phagocytosed, while large MSP were not. Large MSP occasionally elicited giant cell formation, which was not observed after implantation of small MSP. Cellular and macrophage influx and collagen deposition were increased in small MSP implants compared to large MSP. We conclude that the MSP size influences the FBR and thus might influence clinical outcome when using MSP as a drug delivery device. We propose that a rational choice of MSP size can aid in optimising the therapeutic efficacy of microsphere-based therapies in vivo. PMID:25350249

  11. Chitosan Microspheres in Novel Drug Delivery Systems

    PubMed Central

    Mitra, Analava; Dey, Baishakhi

    2011-01-01

    The main aim in the drug therapy of any disease is to attain the desired therapeutic concentration of the drug in plasma or at the site of action and maintain it for the entire duration of treatment. A drug on being used in conventional dosage forms leads to unavoidable fluctuations in the drug concentration leading to under medication or overmedication and increased frequency of dose administration as well as poor patient compliance. To minimize drug degradation and loss, to prevent harmful side effects and to increase drug bioavailability various drug delivery and drug targeting systems are currently under development. Handling the treatment of severe disease conditions has necessitated the development of innovative ideas to modify drug delivery techniques. Drug targeting means delivery of the drug-loaded system to the site of interest. Drug carrier systems include polymers, micelles, microcapsules, liposomes and lipoproteins to name some. Different polymer carriers exert different effects on drug delivery. Synthetic polymers are usually non-biocompatible, non-biodegradable and expensive. Natural polymers such as chitin and chitosan are devoid of such problems. Chitosan comes from the deacetylation of chitin, a natural biopolymer originating from crustacean shells. Chitosan is a biocompatible, biodegradable, and nontoxic natural polymer with excellent film-forming ability. Being of cationic character, chitosan is able to react with polyanions giving rise to polyelectrolyte complexes. Hence chitosan has become a promising natural polymer for the preparation of microspheres/nanospheres and microcapsules. The techniques employed to microencapsulate with chitosan include ionotropic gelation, spray drying, emulsion phase separation, simple and complex coacervation. This review focuses on the preparation, characterization of chitosan microspheres and their role in novel drug delivery systems. PMID:22707817

  12. Interpretability of the PedsQL gastrointestinal symptoms scales and gastrointestinal worry scales in pediatric patients with functional and organic gastrointestinal diseases

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The present study investigates the clinical interpretability of the Pediatric Quality of Life Inventor (PedsQL) Gastrointestinal Symptoms Scales and Worry Scales in pediatric patients with functional gastrointestinal disorders or organic gastrointestinal diseases in comparison with healthy controls....

  13. Apparatus for washing particulate material. [Removal of silicone oil from microspheres by trichloroethylene

    DOEpatents

    Rivera, A.L.; Fowler, V.L.; Justice, G.V.

    1983-12-29

    Transport of nuclear fuel microspheres through a wash liquid is facilitated by feeding a slurry containing the microspheres into the wash liquid via a column having a vibrating tubular screen located under its lower end.

  14. Hierarchical porous polycaprolactone microspheres generated via a simple pathway combining nanoprecipitation and hydrolysis.

    PubMed

    Fan, Hailong; Jin, Zhaoxia

    2015-10-21

    We demonstrated a one-pot, soap-free fabrication of porous polycaprolactone microspheres by combining nanoprecipitation and hydrolysis. The obtained porous polycaprolactone microspheres show great advantages for application in drug delivery. PMID:26324843

  15. A Radically New Method for Hydrogen Storage in Hollow Glass Microspheres

    SciTech Connect

    James E. Shelby; Matthew M. Hall; Michael J. Snyder; Peter B. Wachtel

    2009-07-13

    The primary goal of this project is to demonstrate that hydrogen gas can be rapidly extracted from hollow glass microspheres (HGMS) using a photo-induced heating effect. The results of the project demonstrate that diffusion of hydrogen is readily induced by exposure to light from an IR lamp in transition metal-doped HGMS filled to as much as 5,000 psi with hydrogen gas, which contain approximately 2.2 wt% hydrogen. Doped HGMS in conjunction with optically induced outgassing provide a solution to the traditional limitation of HGMS – i.e., the slow release of hydrogen from HGMS that are heated using a furnace. This information will also be invaluable in designing process changes for future production of HGMS able to hold higher pressures of hydrogen.

  16. Biodegradable poly(lactic-co-glycolic acid) microspheres loaded with S-nitroso-N-acetyl-D-penicillamine for controlled nitric oxide delivery.

    PubMed

    Lautner, Gergely; Meyerhoff, Mark E; Schwendeman, Steven P

    2016-03-10

    Nitric oxide (NO) is a fascinating and important endogenous free-radical gas with potent antimicrobial, vasodilating, smooth muscle relaxant, and growth factor stimulating effects. However, its wider biomedical applicability is hindered by its cumbersome administration, since NO is unstable especially in biological environments. In this work, to ultimately develop site-specific controlled release vehicles for NO, the NO donor S-nitroso-N-acetyl-D-penicillamine (SNAP) was encapsulated within poly(lactic-co-glycolic acid) 50:50 (PLGA) microspheres by using a solid-in-oil-in-water emulsion solvent evaporation method. The highest payload was 0.56(±0.01) μmol SNAP/mg microspheres. The in vitro release kinetics of the donor were controlled by the bioerosion of the PLGA microspheres. By using an uncapped PLGA (Mw=24,000-38,000) SNAP was slowly released for over 10days, whereas by using the ester capped PLGA (Mw=38,000-54,000) the release lasted for over 4weeks. The presence of copper ions and/or ascorbate in solution was necessary to efficiently decompose the released NO donor and obtain sustained NO release. It was also demonstrated that light can be used to induce rapid NO release from the microspheres over several hours. SNAP exhibited excellent storage stability when encapsulated in the PLGA microspheres. These new microsphere formulations may be useful for site-specific administration and treatment of pathologies associated with dysfunction in endogenous NO production, e.g. treatment of diabetic wounds, or in diseases involving other biological functions of NO including vasodilation, antimicrobial, anticancer, and neurotransmission. PMID:26763376

  17. In vitro model alveoli from photodegradable microsphere templates.

    PubMed

    Lewis, Katherine J R; Tibbitt, Mark W; Zhao, Yi; Branchfield, Kelsey; Sun, Xin; Balasubramaniam, Vivek; Anseth, Kristi S

    2015-06-01

    Recreating the 3D cyst-like architecture of the alveolar epithelium in vitro has been challenging to achieve in a controlled fashion with primary lung epithelial cells. Here, we demonstrate model alveoli formed within a tunable synthetic biomaterial platform using photodegradable microspheres as templates to create physiologically relevant, cyst structures. Poly(ethylene glycol) (PEG)-based hydrogels were polymerized in suspension to form microspheres on the order of 120 μm in diameter. The gel chemistry was designed to allow erosion of the microspheres with cytocompatible light doses (≤15 min exposure to 10 mW cm(-2) of 365 nm light) via cleavage of a photolabile nitrobenzyl ether crosslinker. Epithelial cells were incubated with intact microspheres, modified with adhesive peptide sequences to facilitate cellular attachment to and proliferation on the surface. A tumor-derived alveolar epithelial cell line, A549, completely covered the microspheres after only 24 hours, whereas primary mouse alveolar epithelial type II (ATII) cells took ∼3 days. The cell-laden microsphere structures were embedded within a second hydrogel formulation at user defined densities; the microsphere templates were subsequently removed with light to render hollow epithelial cysts that were cultured for an additional 6 days. The resulting primary cysts stained positive for cell-cell junction proteins (β-catenin and ZO-1), indicating the formation of a functional epithelial layer. Typically, primary ATII cells differentiated in culture to the alveolar epithelial type I (ATI) phenotype; however, each cyst contained ∼1-5 cells that stained positive for an ATII marker (surfactant protein C), which is consistent with ATII cell numbers in native mouse alveoli. This biomaterial-templated alveoli culture system should be useful for future experiments to study lung development and disease progression, and is ideally suited for co-culture experiments where pulmonary fibroblasts or endothelial

  18. Synthesis of novel aminated cellulose microsphere adsorbent for efficient Cr(VI) removal

    NASA Astrophysics Data System (ADS)

    Yu, Tianlin; Liu, Siqi; Xu, Min; Peng, Jing; Li, Jiuqiang; Zhai, Maolin

    2016-08-01

    A novel aminated cellulose microsphere adsorbent (CVN) was successfully prepared by radiation-induced graft polymerization of vinylbenzyl chloride (VBC) onto cellulose microsphere (CMS), followed by amination. Micro-FTIR, XPS and SEM confirmed the structure of CVN. The adsorption behavior of Cr(VI) onto CVN from solution was well fitted by the pseudo-second order kinetic model. The isothermal adsorption of Cr(VI) was observed at pH 4.68 with adsorption capacity of 129 mg/g in accordance with Langmuir thermal model, and the removal of Cr(VI) from solution could be 91% at a low amount (20 mg) of adsorbent. The best pH for adsorption of Cr(VI) was nearly 3.08, and with the increasing of temperature, the adsorption capacity of Cr(VI) increased. XPS analysis confirmed the adsorption mechanism of Cr(VI) was ion-exchange mechanism, while common co-ions such as Na+, Mg2+, Cu2+, Ca2+, Zn2+, Ni2+, Cl-, NO3- has no significant effect on the adsorption capacity of Cr(VI), and the Cr(VI) removal of 80% still could be obtained compared with that of fresh CVN adsorbent. Finally, spent CVN could be regenerated under 2 mol/L NaCl. The work indicated that aminated cellulose adsorbent could be prepared successfully by radiation-induced grafting and amination and CVN is a promising bio-adsorbent in the removing Cr(VI) from waste water.

  19. Cytotoxic T cell vaccination with PLGA microspheres interferes with influenza A virus replication in the lung and suppresses the infectious disease.

    PubMed

    Herrmann, Valerie L; Hartmayer, Carmen; Planz, Oliver; Groettrup, Marcus

    2015-10-28

    Current influenza virus vaccines aim to elicit antibodies directed toward viral surface glycoproteins, which however are prone to antigenic drift. Cytotoxic T lymphocytes (CTLs) can exhibit heterosubtypic immunity against most influenza A viruses. In our study, we encapsulated the highly conserved, immunodominant, HLA-A*0201 restricted epitope from the influenza virus matrix protein M158-66 together with TLR ligands in biodegradable poly(d,l-lactide-co-glycolide) (PLGA) microspheres. Subcutaneous immunization of transgenic mice expressing chimeric HLA-A*0201 molecules with these microspheres induced a strong and sustained CTL response which sufficed to prevent replication of a recombinant vaccinia virus expressing the influenza A virus (IAV) matrix protein but not the replication of IAV in the lung. However, subcutaneous priming followed by intranasal boosting with M158-66 bearing PLGA microspheres was able to induce vigorous CTL responses both in the lung and spleen of mice which interfered with IAV replication, weight loss, and infection-related death. Taken together, vaccination with well-defined and highly conserved IAV-derived CTL epitopes encapsulated into clinically compatible PLGA microspheres contribute to the control of influenza A virus infections. The promptitude and broad reactivity of the CTL response may help to attenuate pandemic outbreaks of influenza viruses. PMID:26276509

  20. Spray dried microspheres based on chitosan: A promising new carrier for intranasal administration of polymeric antigen BLSOmp31 for prevention of ovine brucellosis.

    PubMed

    Díaz, Alejandra Graciela; Quinteros, Daniela Alejandra; Llabot, Juan Manuel; Palma, Santiago Daniel; Allemandi, Daniel Alberto; Ghersi, Giselle; Zylberman, Vanesa; Goldbaum, Fernando Alberto; Estein, Silvia Marcela

    2016-05-01

    Previous studies have demonstrated that parenteral immunization with polymeric antigen BLSOmp31 induced a strong immune response and conferred protection against Brucella ovis in rams. This work describes the development of a novel formulation strategy for the delivery of BLSOmp31 in the nasal mucosa. Chitosan microparticles were prepared by spray-drying technology processes and recombinant chimera BLSOmp31 was loaded by passive adsorption onto chitosan microspheres, which were characterized by means of the evaluation of size, zeta potential, morphology, and loading and release rate of BLSOmp31. The mucoadhesive properties of microspheres were evaluated by studying the interaction between microparticles and mucin. The antigen BLSOmp31 integrity was investigated by SDS-PAGE. The yield of production of spray-drying process was 68.95%. Microspheres had a good sphericity, 1-10 μm of particle size and had a positive charge. The loading capacity was found to be 45.19%. The initial fast release of BLSOmp31 from chitosan microparticles was 60%. The BLSOmp31 integrity was not affected by passive adsorption (ionic interaction). The amount of mucin adsorbed on the surface of CMs-BLSOmp31 was lower than on the surface of blank CMs at neutral pH. In vivo studies were carried out in rams. Intranasal immunization induced systemic and local antibodies. In conclusion, the use of BLSOmp31-loaded chitosan spray-drying microspheres offers a promising way for nasal mucosal vaccination in sheep against brucellosis. PMID:26952451