Biomedical subjects

I Han

Publications and source records attributed to I Han.

At least 19 recordsLinked to original sources

PubMed2006

Quality of fresh chicken breasts using a combination of modified atmosphere packaging and chlorine dioxide sachets.

The objective of this research was to observe the effect of chlorine dioxide (ClO2) combined with modified atmosphere packaging on the quality of fresh chicken breasts under refrigerated storage for 15 days. Each chicken breast was inoculated with a 4-log CFU/ml culture of Salmonella Typhimurium (nalidixic acid-resistant strain) and placed into a barrier foam tray. Fast- or slow-release ClO2 sachets were placed next to the chicken in each package. A control set of packages that did not contain a ClO2 sachet was also included in the study. Packages were flushed with either 100% N2 or 75% N2-25% CO2 and stored at 3 degrees C. Microbial analysis, CIE L.a.b. color, and sensory (appearance and aroma) were performed every 3 days for 15 days. Total plate counts for chicken increased steadily after 6 to 9 days of storage regardless of package atmosphere or ClO2 treatment. However, those treated with ClO2 sachets had 1 to 1.5 log CFU per chicken breast lower total plate counts compared with those without ClO2 sachets. After 15 days, samples treated with ClO2 (fast- and slow-release sachets) had significantly lower Salmonella Typhimurium (nalidixic acid-resistant strain) populations (approximately 1 log) compared with chicken that did not contain ClO2 sachets. The ClO2 adversely affected the color of the chicken in areas close to the sachet. No off-odor was detected by the sensory panelists.

Animals↗

PubMed2005

Characterization of humic substances isolated from Han River water and change in the structural and chemical characteristics by ozonation.

This study investigated the characteristics of extracted humic substances, which are ubiquitous in river waters and affect the treatment of water. Humic substances were extracted from the Han River water and analyzed using the samples obtained before/after ozonation with various analytical items. Ozonation was conducted in a batch-type reactor, and ozone was dosed from 0 to 2.0 mg O3 mg(-1) humic substances. The humic fraction was 56.0% of total organic carbon in the Han River and the ratio of fulvic to humic acids was approximately 3.46, including aromatic ring structures and/or various functional groups. Humic substances could not completely be oxidized to CO2, H2O, etc., but partly oxidized to low molecular weight matter, thus low removal efficiencies in terms of dissolved organic carbon (31% at 1.0 mg O3 mg(-1) humic substances) were observed. For UV absorbance at the wavelength 254 nm, ozone dose at 1.0 mg O3 mg(-1) humic substances showed more than 80% removal efficiencies. The molar ratios of H/C and O/C of the humic substances structure relatively increased by ozonation, indicating the degradation of aromatic groups in the humic substances molecule. The Fourier transform infrared spectra and proton nuclear magnetic resonance spectra of humic substances showed the increase in carboxylic acids and the decrease in aromatic protons through ozonation, respectively. As specific reaction sites in the humic substances including aromatic ring structures were reduced through ozone oxidation, contents of carboxylic acids, ketones and quinones in the humic substances molecule increased.

Bioreactors↗

PubMed2005

Correlation of the condition of the patellar articular cartilage and patellofemoral symptoms and function in osteoarthritic patients undergoing total knee arthroplasty.

We sought to determine the degree of correlation between the condition of the patellar articular cartilage and patellofemoral symptoms and function in osteoarthritic patients undergoing total knee arthroplasty. The depth of the osteoarthritic lesion, as graded by the Outerbridge classification and its size and location were assessed to determine the condition of the patellar cartilage in 80 consecutive osteoarthritic knees undergoing total knee arthroplasty. The association between the condition of the cartilage and patellofemoral symptoms and function was investigated by correlation analysis. The depth and size of the lesion had a significant but weak correlation with anterior knee pain (r = -0.300 and -0.289; p = 0.007 and 0.009, respectively), whereas location had no significant association (p > 0.05). None had a significant association with patellofemoral functional parameters (chair-rising, stair-climbing, and quadriceps power) (p > 0.05). Our study indicates that patellofemoral symptoms and function are not completely determined by the condition of the cartilage. Caution should be taken when the symptoms and functional limitations are attributed to a lesion in the patellofemoral joint in making a decision regarding patellar resurfacing in total knee arthroplasty.

Aged↗

PubMed2004

Enhanced transfollicular delivery of adriamycin with a liposome and iontophoresis.

To find a better way to deliver drugs into hair follicles, we tried two approaches: single topical application using various liposomes; and iontophoresis combined with topical application of ionic liposome. After delivery of adriamycin (ADR) to wax-depilated rat skin, the transport of the drug was examined under fluorescence microscopy. Most liposomal ADR showed more effective transdermal and transfollicular penetration than free ADR. Among tested liposomes, the non-ionic GDL liposome (GDL/CH/POE-10 = glycerol dilaulate/cholesterol/polyoxyethylene-10) was the most selective to hair follicles against skin, while the cationic liposome (GDL/CH/POE-10/DOTAP, dioleoyl trimethylammonium propane) containing monocationic DOTAP was less selective; however, it was better at improving the delivery amount and penetration of ADR into the follicles and skin. The DMPC/DMPG (7/3) formulation of anionic PC liposome (DMPC/DMPG = dimyristoyl-phosphocholine/-phospoglycerol) showed results similar to the cationic liposome. The DMPC/DMPG (3/7) formulation yielded poor results, however, probably because of its increased viscosity and anionic property. Although ADR delivery was enhanced by liposomal formulations, topical applications had some limitations in delivery capacity and speed. To accelerate delivery, iontophoresis was combined with the cationic liposome at positive 0.2-0.4 mA/cm(2) for 20-30 min. The resulting delivery of ADR through follicular routes was excellent. This combination method diffused ADR 3.0-fold more efficiently, rapidly and deeply than single topical application of cationic liposomal ADR. This system also achieved a 3.5-fold higher diffusive follicular delivery than a free ADR/iontophoresis combination. Furthermore, it was demonstrated that the tetracationic lipid DOSPER and hydrophile spermine could serve as a cationic additive instead of the monocationic DOTAP in the liposome. These results suggest that the combinative system of the topically applied cationic liposome followed by iontophoresis has a significant synergistic effect on the transfollicular delivery of ADR.

Administration, Cutaneous↗

PubMed2002

Ozonation of Han River humic substances.

This study investigated the characteristics of extracted humic substances (HS) which are ubiquitous in river waters and affect the treatment of the water. HS were extracted from the Han River and the samples obtained were analyzed before/after oxidation with the following analytical methods: DOC, THMFP, UV-abs, chemical composition, molecular weight distribution, IR. Ozonation experiments were conducted in batch-type reactors. Ozone dose was 1 mg/L and contact time was varied from 0 to 20 minutes. The fraction of hydrophobic matter was 56.0% of total organic carbon in the Han River and the ratio of humic/fulvic acids was 22.4/77.6, showing high fractions of aromatic and/or double carbon bond functional groups and high fractions of saturated aliphatic carbons. Oxygen fraction of Han HS was relatively high compared with other humic substances (Suwannee River humic and fulvic acids), which are consistent with the results of IR spectra. The IR spectra showed the increase in aliphatic groups by ozonation of the Han HS. Humic substances could not completely be oxidized to CO2, H2O etc., but were partly oxidized to low molecular weight matter (aliphatics, aldehydes, carboxylics, polysaccharides etc.), so low removal efficiencies in terms of DOC (31-35% with 5 minute contact) were observed. For UV254, 5 minute or shorter contact showed more than 80% removal efficiencies.

Benzopyrans↗

PubMed2001

C-terminal heparin-binding domain of fibronectin regulates integrin-mediated cell spreading but not the activation of mitogen-activated protein kinase.

Fibronectin (FN) stimulates multiple signalling events including mitogen-activated protein kinase (MAPK) activation. During cell spreading, both the cell-binding domain and the C-terminal heparin-binding domain (HepII) of FN co-operatively regulate cytoskeleton organization. However, in comparison with the large number of studies on the functions of cell-binding domain, there is little information about the role of HepII. We therefore investigated the effect of HepII on integrin-mediated cell spreading and adhesion on FN and MAPK activation. In contrast with cells on FN substrates, rat embryo fibroblasts on FN120, which lacks HepII, were less spread, had weaker adhesion to FN and failed to form focal adhesions and actin stress fibres. Phosphotyrosine was present in the focal contacts of rat embryo fibroblasts on FN within 30 min but was absent from cells on FN120. Overall, tyrosine phosphorylation was much less in cell lysates from cells on FN120, with decreased phosphorylation of focal adhesion kinase ('pp125FAK') on tyrosine-397, implying additional regulation of tyrosine phosphorylation by HepII. Nevertheless, adhesion-mediated MAPK activity was similar in cells on FN and on FN120. Furthermore, cells spread on FN and on FN120 substrates showed similar MAPK activation in response to treatment with epidermal growth factor and with platelet-derived growth factor. Consistently, overexpression of syndecan-4, which binds to HepII, enhanced cell spreading and adhesion on FN but did not affect integrin-mediated MAPK activation. We therefore conclude that both HepII and syndecan-4 regulate integrin-mediated cell spreading but not MAPK activation.

Actins↗

PubMed2001

Solution structure of the dimeric cytoplasmic domain of syndecan-4.

The syndecans, transmembrane proteoglycans which are involved in the organization of cytoskeleton and/or actin microfilaments, have important roles as cell surface receptors during cell-cell and/or cell-matrix interactions. Since previous studies indicate that the function of the syndecan-4 cytoplasmic domain is dependent on its oligomeric status, the conformation of the syndecan-4 cytoplasmic domain itself is important in the understanding of its biological roles. Gel filtration results show that the syndecan-4 cytoplasmic domain (4L) itself forms a dimer stabilized by ionic interactions between peptides at physiological pH. Commensurately, the NMR structures demonstrate that syndecan-4L is a compact intertwined dimer with a symmetric clamp shape in the central variable V region with a root-mean-square deviation between backbone atom coordinates of 0.95 A for residues Leu(186)-Ala(195). The molecular surface of the 4L dimer is highly positively charged. In addition, no intersubunit NOEs in membrane proximal amino acid resides (C1 region) have been observed, demonstrating that the C1 region is mostly unstructured in the syndecan-4L dimer. Interestingly, two parallel strands of 4L form a cavity in the center of the dimeric twist similar to our previously reported 4V structure. The overall topology of the central variable region within the 4L structure is very similar to that of 4V complexed with the phosphatidylinositol 4,5-bisphosphate; however, the intersubunit interaction mode is affected by the presence of C1 and C2 regions. Therefore, we propose that although the 4V region in the full cytoplasmic domain has a tendency for strong peptide--peptide interaction, it may not be enough to overcome the repulsion of the C1 regions of syndecan-4L.

Amino Acid Sequence↗

PubMed2001

Rat embryo fibroblasts require both the cell-binding and the heparin-binding domains of fibronectin for survival.

Fibronectin (FN) is known to transduce signal(s) to rescue cells from detachment-induced apoptosis (anoikis) through an integrin-mediated survival pathway. However, the functions of individual FN domains have not been studied in detail. In the present study we investigated whether the interaction of the cell-binding domain of FN with integrin is sufficient to rescue rat embryo fibroblasts (REFs) from detachment-induced apoptosis. REFs attached and spread normally after plating on substrates coated with either intact FN or a FN fragment, FN120, that contains the cell-binding domain but lacks the C-terminal heparin-binding domain, HepII. REFs on FN maintained a well-spread fibroblastic shape and even proliferated in serum-free medium at 20 h after plating. In contrast, previously well-spread REFs on FN120 started losing fibroblastic shape with time and detached from FN120-coated plates after approx. 8 h. Nuclear condensation indicated apototic cell death. This was due to the decreased activity/stability of focal adhesion kinase (pp125FAK) in the absence of HepII domain. A peptide in the HepII domain [peptide V, WQPPRARI (single-letter amino acid codes)], which has previously been implicated in cytoskeletal organization, rescued apoptotic changes. Consistently, pp125FAK phosphorylation was increased, and both cleavage of pp125FAK and activation of caspase 3 on FN120 were partly blocked by peptide V. Thus the interaction of the cell-binding domain with integrin has a major role in cell survival but is itself not sufficient for cell survival. One or more additional survival signals come from the HepII domain to regulate pp125FAK activity/stability.

Amino Acid Sequence↗

PubMed2001

Dietary restriction impairs neutrophil exudation by reducing CD11b/CD18 expression and chemokine production.

HYPOTHESIS: Patients with malnutrition are susceptible to infection. Polymorphonuclear neutrophils (PMNs) are the major effector of the nonspecific immune response in host resistance to infection. Dietary restriction may impair PMN-mediated immunity in the peritoneal cavity by reducing PMN exudation, adhesion molecule expression on PMNs, and chemokine production. DESIGN: Randomized study of murine glycogen-induced peritonitis with dietary restriction. SETTING: University research laboratory. MATERIALS: Male C57BL/6J mice. INTERVENTIONS: Mice (N = 204) were assigned to ad libitum, moderate, and severe diet-restricted groups receiving mouse chow ad libitum (132 g/kg, 66 g/kg, and 33 g/kg daily for 7 days, respectively). After dietary restriction with or without 1 day of refeeding, mice were administered glycogen intraperitoneally to induce cell exudation. MAIN OUTCOME MEASURES: CD11b, CD18, and CD62L expressions on circulating PMNs, phagocytosis, and reactive oxygen intermediate production by exudative PMNs were measured after glycogen installation. The levels of PMN-specific chemokine, macrophage inflammatory protein 2 (MIP-2), in peritoneal lavage fluid were also measured. These parameters were measured after glycogen installation in the refeeding experiment. RESULTS: Seven days of dietary restriction decreased CD11b/CD18 expression on circulating PMNs, MIP-2 levels in peritoneal lavage fluid, and subsequent PMN exudation into the peritoneal cavity early in peritonitis. Both CD11b and CD18 expression on circulating PMNs and MIP-2 levels correlated significantly with numbers of exudative PMNs. Seven days of dietary restriction also impaired phagocytosis, while up-regulating reactive oxygen intermediate production by exudative PMNs. Only 1 day of ad libitum refeeding normalized CD11b/CD18 expression with PMN exudation into the peritoneal cavity. CONCLUSIONS: Short-term dietary restriction impairs PMN exudation into local inflammatory sites in murine peritonitis by reducing CD11b/CD18 expression and MIP-2 production. Even brief nutritional replenishment in diet-restricted patients may improve host defense via restoring these PMN functions and chemokine production at local inflammatory sites.

Animals↗

PubMed2001

Effects of pH and dissolved oxygen on the reduction of hexavalent chromium by dissolved ferrous iron in poorly buffered aqueous systems.

The effects of pH and dissolved oxygen (DO) on the reduction of Cr(VI) by dissolved Fe(II) were investigated for aqueous solutions having relatively low buffering capacities. All solutions were maintained at a constant ionic strength (generally 0.05 M) and temperature (23 +/- 2 degrees C). For the majority of the experiments conducted, initial concentrations of Fe(II) and Cr(VI) were 50 and 20 microM, respectively, representing a deficient amount of Fe(II) (i.e. nonstoichiometric conditions). Experiments conducted in the absence and presence of DO were performed in an anaerobic chamber and in vessels open to the atmosphere, respectively. Specific initial pH values were obtained by adjusting the pH of Cr(VI) and Fe(II) stock solutions prior to their mixing or by spiking Cr(VI)-Fe(II) systems with strong base to rapidly increase the pH in situ. Consistent with previous reports, Cr(VI) reduction rates for our systems increased with increasing pH (pH ranges of 3.5-6 and 3.5-7.2 for oxic and anoxic experiments, respectively). Because of our poorly buffered experimental systems, pH values decreased over the course of the reactions which, in turn, caused decreases in the reduction rates with time. Spiking some experimental systems with NaOH to rapidly raise the pH resulted in faster rates of Cr(VI) reduction than when the pH was adjusted prior to mixing the stock solutions together; this observation is likely due to the presence of microenvironments in the reactors for which local, short-term pH values greatly exceed the equilibrium value (i.e. mixing is slower than the reduction reaction in these high pH microenvironments). The molar ratios of Fe(II) oxidized to Cr(VI) reduced were close to the expected stoichiometric value of 3 for the majority of our experimental systems, which shows that DO will not cause a serious interference in most applications using Fe(II) to reduce Cr(VI).

Buffers↗

PubMed2001

DiSSiMiL: Diverse Small Size Mini-Libraries applied to simple and rapid epitope mapping of a monoclonal antibody.

Methods for screening protein-protein interactions are useful in protein science and for the generation of drug leads. We set out to develop a simplified assay to rapidly test protein-protein interactions, with a library of 400 pentapeptides comprising the 20 natural amino acids at two variable positions followed by three glycines (NH2-X1X2GGG). The library was used to identify the epitope of monoclonal antibody (mAb) 10D11 directed against the HOXD4 protein. Three pentapeptide 'hits' were selected (VYGGG, PWGGG and WKGGG) from direct binding assays screening for pentapeptide-mAb interactions; and from assays using pentapeptides in solution to competitively block HOXD4-mAb interactions. Alignment of the three 'hit' pentapeptides to the HOXD4 sequence predicts the mAb 10D11 epitope as NH2-VYPWMK. Synthesis of NH2-VYPWMK hexapeptide confirmed this prediction; and an alanine scan of HOXD4 ablated binding by mAb 10D11 when amino acids in the putative epitope were mutated. We propose that these simplified but diverse libraries can be used for rapid epitope mapping of some mAbs, and for generating lead small peptide analogs that interfere with receptor-ligand or other protein-protein interactions, or with enzymatic activity.

Amino Acid Sequence↗

PubMed2001

Cytokine-modulated inhibition of neutrophil apoptosis at local site augments exudative neutrophil functions and reflects inflammatory response after surgery.

BACKGROUND: The fate of exudative polymorphonuclear neutrophils (PMNs) at the local site after surgery is not well understood. We evaluated the fate and functions of exudative PMNs at the local site in patients who were undergoing major surgery. We also investigated the relation between PMN apoptosis and cytokine levels at the local site during the postoperative period. METHODS: Exudative PMNs were isolated from 11 patients during the postoperative period. Apoptosis, reactive oxygen intermediates (ROI) production, CD16, and tumor necrosis factor receptor expression of the PMNs were determined by flow cytometry. Cytokine levels in the drainage fluid were measured. RESULTS: Exudative PMN apoptosis was markedly inhibited on postoperative day 1 and then increased in a time-dependent manner. IL-6 and granulocyte macrophage colony-stimulating factor were significant factors to inhibit exudative PMN apoptosis; tumor necrosis factor-alpha and IL-10 were the factors to increase apoptosis. ROI production and CD16 expression of exudative PMNs were augmented when PMN apoptosis was inhibited in the early postoperative period. CONCLUSIONS: Exudative PMN apoptosis was inhibited after surgery; PMN function was augmented after surgery. Cytokines at the local site may modulate exudative PMN apoptosis. Exudative PMN apoptosis reflected the inflammatory response after surgery. Understanding the mechanisms of PMN apoptosis and its pathophysiologic significance at local inflammatory sites in vivo may help in the design of more rational treatments.

Aged↗

PubMed2001

Ex vivo fluorescence microscopy provides simple and accurate assessment of neutrophil-endothelial adhesion in the rat lung.

Neutrophil adhesion to the pulmonary endothelium is prerequisite to neutrophil transmigration and activation, both of which may lead to lung injury. A simple method to evaluate neutrophil adherence in the lung would be useful for developing new strategies for neutrophil-mediated lung injury. The purpose was to establish a simple method to evaluate neutrophil adhesion in the lung using ex vivo fluorescence microscopy. Rats were anesthetized, and the right jugular veins were catheterized. Neutrophils were isolated from another set of rats and labeled with 5,(6)-carboxyfluorescein diacetate. Animals were killed 120 s after a 1 x 10(6) labeled neutrophil injection. The pulmonary labeled neutrophil number was counted under a fluorescence microscope. In the first experiment, rats were given 0, 20, 200, or 2000 microg/kg lipopolysaccharide (LPS) i.p. At 4 h after challenge, the pulmonary labeled neutrophil number was determined. Kinetic studies were also performed at 0, 1, 4, and 8 h after 200 microg/kg LPS. Finally, anti-ICAM-1 Ab was injected i.v. before LPS 200 microg/kg, and the labeled neutrophil number in the lung was determined at 4 h. The number of pulmonary labeled neutrophils was higher after LPS 200 or 2000 microg/kg than after the other doses. The pulmonary labeled neutrophil number was increased at 4 h compared with the other time points. ICAM-1 blocking normalized the pulmonary labeled neutrophil number in the LPS group. In conclusion, our method seems to reflect ICAM-1-mediated neutrophil adherence to the endothelium in the present setting. This simple technique may be useful for evaluating neutrophil adhesion.

Animals↗

PubMed2001

EBNA-LP associates with cellular proteins including DNA-PK and HA95.

EBNA-LP-associated proteins were identified by sequencing proteins that immunoprecipitated with Flag epitope-tagged EBNA-LP (FLP) from lymphoblasts in which FLP was stably expressed. The association of EBNA-LP with Hsp70 (72/73) was confirmed, and sequences of DNA-PK catalytic subunit (DNA-PKcs), HA95, Hsp27, prolyl 4-hydroxylase alpha-1 subunit, alpha-tubulin, and beta-tubulin were identified. The fraction of total cellular HA95 that associated with FLP was very high, while progressively lower fractions of the total DNA-PKcs, Hsp70, Hsp 27, alpha-tubulin, and beta-tubulin specifically associated with EBNA-LP as determined by immunoblotting with antibodies to these proteins. EBNA-LP bound to two domains in the DNA-PKcs C terminus and DNA-PKcs associated with the EBNA-LP repeat domain. DNA-PKcs that was bound to EBNA-LP phosphorylated p53 or EBNA-LP in vitro, and the phosphorylation of EBNA-LP was inhibited by Wortmannin, a specific in vitro inhibitor of DNA-PKcs.

DNA-Activated Protein Kinase↗

PubMed2000

Intercellular delivery of a herpes simplex virus VP22 fusion protein from cells infected with lentiviral vectors.

Effective gene therapy depends on the efficient transfer of therapeutic genes and their protein products to target cells. Lentiviral vectors appear promising for virus-mediated gene delivery and long-term expression in nondividing cells. The herpes simplex virus type 1 tegument protein VP22 has recently been shown to mediate intercellular transport of proteins, raising the possibility that it may be helpful in a setting where the global delivery of therapeutic proteins is desired. To investigate the effectiveness of lentiviral vectors to deliver genes encoding proteins fused to VP22, and to test whether the system is sufficiently potent to allow protein delivery from transduced cells in vitro and in vivo, fusion constructs of VP22 and the enhanced green fluorescent protein (EGFP) were prepared and delivered into target cells by using HIV-1-based lentiviral vectors. To follow the spread of VP22-EGFP to other cells, transduced COS-7 cells were coplated with a number of different cell types, including brain choroid plexus cells, human endothelial cells, H9 cells, and HeLa cells. We found that VP22-EGFP fusion proteins were transported from transduced cells to recipient cells and that such fusion proteins accumulated in the nucleus and in the cytoplasm of such cells. To determine the ability to deliver fusion proteins in vivo, we injected transduced H9 cells as well as the viral vector directly into the brain of mice. We present evidence that VP22-EGFP fusion proteins were transported effectively from lentivirus transduced cells in vivo. We also show that the VP22-EGFP fusion protein encoded by the lentivirus is transported between cells. Our data indicate that such fusion proteins are present in the nucleus and in the cytoplasm of neighboring cells. Therefore, lentiviral vectors may provide a potent biological system for delivering genes encoding therapeutic proteins fused to VP22.

Animals↗

PubMed2000

Responsiveness of the state of O-linked N-acetylglucosamine modification of nuclear pore protein p62 to the extracellular glucose concentration.

O-linked N-acetylglucosamine (O-GlcNAc) modification has been described in many proteins, including nuclear pore glycoproteins. In the present study we investigated the effect of extracellular glucose on the level of modification of nuclear pore protein p62 by O-GlcNAc. We found that exposure of cells to a high concentration of glucose caused an increased level of modification of p62 with O-GlcNAc, whereas the modification of other proteins did not change detectably. The increased O-GlcNAc modification of p62 in response to glucose required the metabolism of glucose to glucosamine. The exposure of the cells to glucosamine itself also caused increased O-GlcNAc modification, whereas mannosamine and galactosamine did not. Furthermore, changes in glucose concentrations within the physiological range induced the O-GlcNAc modification in p62 in rat aortic smooth-muscle cells, indicating that this modification of p62 might occur in an intact animal. These results imply that the ambient glucose concentration has an impact on the level of O-GlcNAc modification of proteins such as p62, and that functional changes in some of these proteins might ensue.

Acetylglucosamine↗

PubMed2000

Supplemental glutamine augments phagocytosis and reactive oxygen intermediate production by neutrophils and monocytes from postoperative patients in vitro.

The energy substrate for neutrophils has been believed to be glucose. However, a recent investigation has demonstrated that neutrophils use glutamine (Gln) as well as glucose. Nevertheless, little is known about the effects of Gln on neutrophil function. Thus, this study was designed to investigate the effects of Gln on phagocytosis and reactive oxygen intermediate (ROI) production by neutrophils from postoperative patients in vitro. Eleven patients who had undergone major gastrointestinal surgery were randomly selected. Peripheral blood was drawn before surgery and on postoperative days (PODs) 1, 3, and 7. The blood was washed with medium to remove plasma. Washed whole blood was incubated in RPMI 1640 medium containing neither Gln nor glucose for 24 h at 37 degrees C. The medium was supplemented with Gln at a concentration of 0, 500, 1000, or 2000 microM. Whole blood was then assessed for phagocytosis by flow cytometry using fluorescent beads. ROI production by phagocytes was measured by flow cytometry using dihydrorhodamine 123. In each assay, the neutrophil population was gated and analyzed. Serum amino acids were also measured. Postoperative serum Gln level decreased significantly until POD 7. Phagocytosis by neutrophils on PODs 3 and 7 was significantly greater at 2000 microM Gln than at other Gln concentrations. Neutrophil ROI production was significantly greater at 2000 microM Gln than at 0 microM Gln at each time point. In conclusion, supplemental Gln enhances both phagocytosis and ROI production by neutrophils from postoperative patients in vitro.

Aged↗

PubMed2000

Relative effects of glucose and glutamine on reactive oxygen intermediate production by neutrophils.

The energy source for neutrophils (PMNs) has long been believed to be glucose. However, it has been shown recently that PMNs use glutamine as well as glucose. Nevertheless, the comparative effects of glucose and glutamine on PMN function remain to be clarified. This study investigated the relative effects of glucose and glutamine on reactive oxygen intermediate (ROI) production by PMNs. In experiment 1, PMNs (1 x 10(6)/mL) isolated from healthy volunteers were incubated in RPMI 1640 medium containing neither glucose nor glutamine for 4, 12, 18, and 24 h at 37 degrees C. The medium was supplemented with 0 or 200 mg/dL (0 or 11 mM, respectively) glucose and glutamine (0, 0.5, 1, or 2 mM). PMN cell death was assessed on the basis of hypodiploid DNA by flow cytometry using propidium iodide DNA staining. ROI production by PMNs was determined by flow cytometry using dihydrorhodamine 123. In experiment 2, isolated PMNs were cultured in RPMI 1640 medium containing neither glucose nor glutamine. The medium was supplemented with glucose (0 or 11 mM) and a competitive inhibitor of glycolysis, 2-deoxy-D-glucose (2-DG; 0 or 20 mM). Each medium was supplemented with glutamine (0, 0.5, 1, or 2 mM) and incubated for 12 h at 37 degrees C. Then, ROI production by PMNs was measured. PMN cell death was not affected by glucose or glutamine in this experiment. In contrast, ROI production by PMNs was greater at 11 mM glucose than at 0 mM glucose at all incubation times studied. At 11 mM glucose, supplemental glutamine enhanced PMN ROI production after 18 and 24 h culture. In contrast, at 0 mM glucose, glutamine augmented ROI production by PMNs after 12 h as well as with 18 and 24 h incubations. PMN ROI production after 12 h culture was significantly greater at 11 mM glucose without 2-DG than at both 11 and 0 mM glucose with addition of 2-DG. In addition, supplemental glutamine enhanced ROI production by PMNs when 2-DG was added at 11 and 0 mM glucose. Glucose is essential for PMN ROI production. Under conditions of glucose depletion in vitro, glutamine is of importance in ROI production by PMNs, whereas the enhancing effect of glutamine on PMN ROI production is minor compared to that of glucose.

Cells, Cultured↗