1
|
Wijendran V, Brenna JT, Wang DH, Zhu W, Meng D, Ganguli K, Kothapalli KSD, Requena P, Innis S, Walker WA. Long-chain polyunsaturated fatty acids attenuate the IL-1β-induced proinflammatory response in human fetal intestinal epithelial cells. Pediatr Res 2015; 78:626-33. [PMID: 26270575 PMCID: PMC5046822 DOI: 10.1038/pr.2015.154] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 05/13/2015] [Indexed: 11/09/2022]
Abstract
BACKGROUND Evidence suggests that excessive inflammation of the immature intestine may predispose premature infants to necrotizing enterocolitis (NEC). We investigated the anti-inflammatory effects of docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and arachidonic acid (ARA) in human fetal and adult intestinal epithelial cells (IEC) in primary culture. METHODS Human fetal IEC in culture were derived from a healthy fetal small intestine (H4) or resected small intestine of a neonate with NEC (NEC-IEC). Intestinal cell lines Caco2 and NCM460 in culture were used as models for mature IEC. IEC in culture were pretreated with 100 µmol/l palmitic acid (PAL), DHA, EPA, ARA, or ARA+DHA for 48 h and then stimulated with proinflammatory IL-1β. RESULTS DHA significantly attenuated IL-1β induced proinflammatory IL-8 and IL-6 protein and mRNA in fetal H4, NEC-IEC, and mature Caco2, NCM460 IEC, compared to control and PAL treatment. DHA downregulated IL-1R1 (IL-1β receptor) and NFk β1 mRNA expression in fetal and adult IEC. ARA had potent anti-inflammatory effects with lower IL-8 and IL-6 (protein and mRNA) in fetal H4 but not in NEC-IEC or adult IEC. CONCLUSION The present study provides evidence that DHA and ARA may have important anti-inflammatory functions for prevention of NEC in premature infants.
Collapse
Affiliation(s)
- Vasuki Wijendran
- Mucosal Immunology and Biology Research Center, Massachusetts General Hospital for Children, Boston, MA, USA
| | - JT Brenna
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, USA
| | - Dong Hao Wang
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, USA
| | - Weishu Zhu
- Mucosal Immunology and Biology Research Center, Massachusetts General Hospital for Children, Boston, MA, USA
| | - Di Meng
- Mucosal Immunology and Biology Research Center, Massachusetts General Hospital for Children, Boston, MA, USA
| | - Kriston Ganguli
- Mucosal Immunology and Biology Research Center, Massachusetts General Hospital for Children, Boston, MA, USA
| | | | - Pilar Requena
- Liverpool School of Tropical Medicine, Liverpool, UK
| | - Sheila Innis
- Department of Pediatrics, University of British Columbia, Vancouver, BC, Canada
| | - WA Walker
- Mucosal Immunology and Biology Research Center, Massachusetts General Hospital for Children, Boston, MA, USA
| |
Collapse
|
2
|
Ruemmele FM, Bier D, Marteau P, Rechkemmer G, Bourdet-Sicard R, Walker WA, Goulet O. Clinical evidence for immunomodulatory effects of probiotic bacteria. J Pediatr Gastroenterol Nutr 2009; 48:126-41. [PMID: 19179874 DOI: 10.1097/mpg.0b013e31817d80ca] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Close, tightly orchestrated interactions between the intestinal epithelium and the mucosa-associated immune system are critical for normal intestinal absorptive and immunological functions. Recent data indicate that commensal intestinal microbiota represents a major modulator of intestinal homeostasis. This review analyzes the process of intestinal colonization and the interaction of microbiota with the intestinal epithelium and mucosal immune system, with special reference to the first years of extrauterine life. Dysregulation of the symbiotic interaction between intestinal microbiota and the mucosa may result in a pathological condition with potential clinical repercussions. Based on the concept that there is a beneficial and symbiotic relation between the host and endogenous microbiota, strategies aimed at directly modulating intestinal microbiota with regard to disease prevention or treatment have been developed. One strategy involves administering viable probiotic bacteria. Clinical evidence for the beneficial effect of probiotics in the prevention and/or treatment of necrotizing enterocolitis, infectious and antibiotic-associated diarrhea, allergic diseases, and inflammatory bowel disorders is reviewed herein.
Collapse
Affiliation(s)
- F M Ruemmele
- Department of Pediatrics, Hôpital Necker-Enfants Malades, Paris, France.
| | | | | | | | | | | | | |
Collapse
|
3
|
Abstract
An important component of bacterial infection of the gastrointestinal tract, particularly when enterotoxin disruption of gut function occurs, relates to the interaction of the bacterium and toxin with the intestinal surface. Adherence or attachment of bacteria lead to colonization and toxic/invasive diarrhoeal states. The purpose of this review is to consider the intestinal mucosal barrier as a deterrent to microbial/toxin attachment, particularly emphasizing the mucosal surface itself, which includes the mucus coat and microvillous membrane. Consequences of mucosal barrier deficiency, particularly the incomplete development of the mucosal barrier, result in bacterially induced diarrhoeal states such as toxigenic diarrhoea and necrotizing enterocolitis. To illustrate the importance of the mucosal barrier as a factor in controlling the external environment containing bacteria and bacterial toxins, recent research in our laboratory on the development of the mucosal barrier is presented. This compares mucosal surface functional control of antigen/toxin attachment and penetration with mucosal surface compositional changes. Finally, evidence of a preliminary nature will be provided to suggest that modifications of the underdeveloped mucosal barrier of the immature intestine by the ingestion of breast milk may act to prevent pathological interactions between the gut and microbes/toxins.
Collapse
|
4
|
Affiliation(s)
- K Bernt
- Developmental Gastroenterology Laboratory, Combined Program in Pediatric Gastroenterology and Nutrition, Massachusetts General Hospital and The Children's Hospital, Boston 02129, USA
| | | |
Collapse
|
5
|
Shah U, Walker WA. Pathophysiology of intestinal food allergy. Adv Pediatr 2002; 49:299-316. [PMID: 12214776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
Abstract
The gastrointestinal tract plays an important role in the mucosal immune response. While acting as a conduit allowing the transfer of nutrients from the intestinal lumen to the systemic circulation, it also protects against invasion by microbes and other antigens by the induction of an immune response. A downregulation of these immune responses to nonharmful antigenic substances is termed oral tolerance. A breakdown or underdevelopment of oral tolerance may therefore lead to the development of food allergy. Adverse immunologic reactions to food may be a consequence of both IgE- and non-IgE-mediated mechanisms. Although genetic factors play a major role in the development of allergic disease, other factors involved in an immature mucosal immune response have been implicated. Non-IgE-mediated allergic responses tend to involve a T cell-mediated delayed hypersensitivity reaction, and released cytokines act as determinants of the immune response. The "hygiene hypothesis" proposes that a reduction in infections in early infancy predisposes to allergic responses. Early childhood infections promote the induction of a T-helper type 1 response that protects against the development of allergy, which is predominantly a T-helper type 2 response. The role of B cells and T cells in the development of food allergy is incompletely under- stood, but advances in the evaluation and characterization of food allergens has opened exciting new avenues in this study.
Collapse
Affiliation(s)
- Uzma Shah
- Combined Program in Pediatric Gastroenterology and Nutrition, Children's Hospital and Massachusetts General Hospital, Boston, USA
| | | |
Collapse
|
6
|
Lazarski MP, Walker WA, Flores CM, Schindler WG, Hargreaves KM. Epidemiological evaluation of the outcomes of nonsurgical root canal treatment in a large cohort of insured dental patients. J Endod 2001; 27:791-6. [PMID: 11771594 DOI: 10.1097/00004770-200112000-00021] [Citation(s) in RCA: 164] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Selected outcomes following initial nonsurgical root canal treatment (NSRCT) procedures were retrospectively assessed using an insurance company database of 110,766 nonsurgical root canal procedures that were completed by endodontists and their referring general dentists. A subset of 44,613 cases, with a minimum required follow-up time of 2 yr, showed incidences of extraction, retreatment and periradicular surgery equal to 5.56%, 2.47%, and 1.41%, respectively. The incidence of subsequent extraction increased with patient age. Teeth that were not restored after root canal therapy were significantly more likely to undergo extraction than restored teeth. Although the practice pattern for endodontists consisted of a significantly higher proportion of molars (48% more; p < 0.001) and a smaller proportion of anterior teeth (43% less; p < 0.001) than general dentists, both groups of providers had comparable rates of untoward events. These data strongly support the hypothesis that the specialist practice provides similar rates of clinical success compared with other providers, even when treating significantly more complex NSRCT cases. Overall, 94.44% of nonsurgical root canal treated teeth remained functional over an average follow-up time of 3.5 yr. These results are an important indication of the benefits of endodontic treatment when provided in an integrated health care delivery system of endodontists and their referring general dentists.
Collapse
Affiliation(s)
- M P Lazarski
- Department of Endodontics, University of Texas Health Science Center at San Antonio, 78284-7894, USA
| | | | | | | | | |
Collapse
|
7
|
Abstract
Many endodontic sealers contain constituents that have been shown to inhibit the polymerization of resin cements. This may be important when prefabricated posts are cemented at the same appointment as root canal obturation. This study evaluated the effects of cementing posts with a resin cement immediately or at a delayed time period after obturation using Roth's 801 Elite Grade or AH26 sealer cements. The contribution of mechanical post-space preparation was also assessed as a critical variable. One hundred twenty extracted canines were randomly divided into eight experimental groups. The variables evaluated were the order of post preparation (either before or after obturation), the type of sealer used, and the time of post cementation. All teeth received a stainless steel #6 Parapost XP cemented with a resin cement, Panavia 21. Each experimental group underwent tensile testing for retention using an Instron universal testing machine. For both sealers posts cemented in teeth in which the canal was obturated before post-space preparation and thus had sealer-contaminated dentin removed by the space preparation procedure had significantly higher retentive values than those obturated after post-space preparation in which contaminated dentin might remain. Sealer used and time of cementation had no specific effect on retention. Achieving a clean, "freshened" dentinal surface during mechanical post-space preparation seems to be a critical variable for post retention when a resin cement is used.
Collapse
Affiliation(s)
- K J Boone
- Department of Endodontics, Wilford Hall USAF Medical Center, Lackland Air Force Base, TX, USA
| | | | | | | |
Collapse
|
8
|
|
9
|
Fernandez IM, Silva M, Schuch R, Walker WA, Siber AM, Maurelli AT, McCormick BA. Cadaverine prevents the escape of Shigella flexneri from the phagolysosome: a connection between bacterial dissemination and neutrophil transepithelial signaling. J Infect Dis 2001; 184:743-53. [PMID: 11517436 DOI: 10.1086/323035] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2001] [Revised: 06/01/2001] [Indexed: 11/04/2022] Open
Abstract
Shigella flexneri causes bacillary dysentery in humans by invading epithelial cells of the colon, which is characterized by an acute polymorphonuclear leukocyte (PMNL)-rich inflammation. Our recent studies demonstrated that cadaverine, a polyamine, specifically acts to abrogate transepithelial signaling to PMNL induced by S. flexneri. Here, insight is provided into the cellular mechanisms by which cadaverine attenuates the ability of Shigella species to induce PMNL signaling. It was found that cadaverine retards the lysis of the Shigella species-containing vacuole, suggesting that a blockade is established, in which the pathogen is prevented from adequately interacting with the cytoskeleton. Furthermore, an IcsA mutant of S. flexneri that cannot interact with the cytoskeleton and spreads intercellularly fails to induce transmigration of PMNL. Results indicate that cadaverine-induced compartmentalization of Shigella species to the phagolysosome might be a protective response of the host that directly contributes to the diminished ability of PMNL to transmigrate across model intestinal epithelia.
Collapse
Affiliation(s)
- I M Fernandez
- Mucosal Immunology Laboratories, Department of Pediatric Gastroenterology and Nutrition, Massachusetts General Hospital, Charlestown, Massachusetts 02129-4404, USA.
| | | | | | | | | | | | | |
Collapse
|
10
|
Savidge TC, Lowe DC, Walker WA. Developmental regulation of intestinal epithelial hydrolase activity in human fetal jejunal xenografts maintained in severe-combined immunodeficient mice. Pediatr Res 2001; 50:196-202. [PMID: 11477203 DOI: 10.1203/00006450-200108000-00006] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Intestinal epithelial brush border hydrolases are important and sensitive enzyme markers of gastrointestinal development and function. Little is know about the mechanisms that regulate the induction of these enzymes during human fetal development, as these events occur primarily in utero. The present work used ectopically grafted human fetal jejunal xenografts (median age,13.3 wk of gestation), maintained in severe-combined immunodeficient mice, to study the differential expression of five different hydrolases after 10 wk of xenotransplantation. The spatio-temporal distribution of brush border alkaline phosphatase, aminopeptidase-N, alpha-glucosidase, lactase-phlorizin hydrolase, and dipeptidyl peptidase IV enzyme activities were measured quantitatively using scanning microdensitometry along the crypt-villus axes of fetal, xenograft, and pediatric (median age, 34 mo) biopsies. Ectopic grafting of fetal jejunum closely recapitulated the development of these enzymes in utero, with alkaline phosphatase, aminopeptidase-N, alpha-glucosidase, and dipeptidyl peptidase IV enzyme activities closely matching the spatio-temporal distribution and levels recorded in pediatric duodenal biopsies. Lactase-phlorizin hydrolase was the only enzyme not to reach values recorded in pediatric brush border membranes, although activities were significantly (5.6-fold) higher than in pretransplanted fetal bowel. Human jejunal xenografts therefore demonstrate an appropriate developmental induction of brush border hydrolase activity and may represent a useful model to study trans-acting factors that promote human epithelial differentiation and function in vivo. Characterization of such agents may be of potential therapeutic use in the treatment of diseases associated with gastrointestinal immaturity, notably necrotizing enterocolitis.
Collapse
Affiliation(s)
- T C Savidge
- Developmental Gastroenterology Laboratory, Combined Program in Pediatric Gastroenterology and Nutrition, Massachusetts General Hospital and Harvard Medical School, 114 16th Street, Charlestown, MA 02129, U.S.A.
| | | | | |
Collapse
|
11
|
Abstract
Neonatal necrotizing enterocolitis (NEC) is a major cause of morbidity in preterm infants. We hypothesize that the intestinal injury in this disease is a consequence of synergy among three of the major risk factors for NEC: prematurity, enteral feeding, and bacterial colonization. Together these factors result in an exaggerated inflammatory response, leading to ischemic bowel necrosis. Human milk may decrease the incidence of NEC by decreasing pathogenic bacterial colonization, promoting growth of nonpathogenic flora, promoting maturation of the intestinal barrier, and ameliorating the proinflammatory response.
Collapse
Affiliation(s)
- E C Claud
- Developmental Gastroenterology Laboratory, Combined Program in Pediatric Gastroenterology and Nutrition, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02129, USA
| | | |
Collapse
|
12
|
Abstract
Communication between microorganisms and the gastrointestinal epithelium, ie, bacterial-epithelial "crosstalk," is examined. Because most basic research on the molecular interaction of bacteria with the gut epithelium relates to pathogen-enterocyte interaction, crosstalk with pathologic bacterial is considered in detail. Through their interactions with the intestinal epithelium, pathogens can modify epithelium function to enhance their penetration across the epithelial barrier and to exploit mucosal host defenses for their own benefit. Three representative pathogens are used to illustrate the various adaptive techniques used to colonize and penetrate the mucosal barrier. Salmonella enterica typhimurium interacts with the physiologic receptor for epidermal growth factor to co-opt the receptor's signal transduction mechanisms. Enteropathic Escherichia coli secretes a receptor (type III secretion) into the microvillus surface of enterocytes that disrupts the microvillus and alters its actin structure to form a dome-like anchoring site. Shigella flexneri is used to illustrate how pathogens use the follicular epithelial cell (M cell), the physiologic conduit for antigens to reach gut associated-lymphoid tissues, for penetration of the epithelial barrier. Shigella organisms attached to M cells use their endocytotic properties to enter the cell. Once inside the cell, the organism lyses the endocytic vacuole and co-opts actin and myosin to form a propelling tail for further penetration of the epithelium through the basolateral surface. Probiotics can protect the intestine by competing with pathogens for attachment, strengthening tight junctions between enterocytes, and enhancing the mucosal immune response to pathogens. However, additional molecular studies are needed to define more precisely the mechanism of probiotic-epithelial crosstalk.
Collapse
Affiliation(s)
- L Lu
- Harvard Medical School, Boston, USA
| | | |
Collapse
|
13
|
Abstract
The intestinal epithelium is an active participant in the mucosal immune response against luminal pathogens. Microorganisms and their cell wall products, i.e. lipopolysaccharide (LPS), can stimulate the enterocyte to produce an innate immune response with the increased production of IL-8 via an activation of the transcription factor NFkappaB. The innate response mechanism, however, has not been understood until the recent description of a family of human toll-like receptors (hTLR) on immune cells that interact with LPS and modulate the IL-8 response via an intracellular signal transduction pathway similar to that of the IL-1 receptor family. Accordingly, in this study we have sought to determine the constitutive and regulated expression of hTLR on a nonmalignant human fetal primary small intestinal cell line (H4 cells) and on small intestinal samples of ileum from human fetuses (age 18-21 wk). Specimens were examined by reverse-transcription PCR, Western blot analysis, and immunofluorescence for hTLR2 and hTLR4 mRNA and protein and to determine whether their expression was regulated by LPS or by an endogenous inflammatory stimulus, IL-1beta. hTLR2 and hTLR4 were expressed constitutively on H4 cells and on human fetal small intestinal enterocytes, predominantly on the basolateral surface of crypt enterocytes. Inflammatory stimuli appeared to regulate hTLR transcription (IL-1beta increased both hTLR2 and hTLR4 whereas LPS decreased hTLR4) and possibly translation (qualitative observations). The presence of hTLR on human fetal enterocyte suggests a mechanism for the innate immune response to pathogens and could provide the basis for further study of the accentuated inflammatory response in age-dependent gastrointestinal diseases such as necrotizing enterocolitis.
Collapse
Affiliation(s)
- R D Fusunyan
- Developmental Gastroenterology Laboratory, Combined Program in Pediatric Gastroenterology and Nutrition, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129-2060, U.S.A
| | | | | | | |
Collapse
|
14
|
Affiliation(s)
- G M Spiekermann
- Harvard Medical School, Gastrointestinal Cell Biology Laboratory, Children's Hospital, Boston, Massachusetts, USA
| | | |
Collapse
|
15
|
Abstract
The purpose of this study was to evaluate the accuracy of the Root ZX in vitro in the presence of a variety of endodontic irrigants. The in vitro model, described by Donnelly, consisted of refrigerated gelatin made with 0.9% sodium chloride instead of water. The following irrigants were tested: 2% lidocaine with 1:100,000 epinephrine, 5.25% sodium hypochlorite, RC Prep, liquid EDTA, 3% hydrogen peroxide, and Peridex. A total of 30 extracted, single-rooted teeth were used. The experimental measurements in the presence of the various irrigants were compared with the actual canal lengths. The present data indicate that the Root ZX electronic apex locator reliably measured canal lengths to within 0.31 mm and that there was virtually no difference in the length determination as a function of the seven irrigants used. These results strongly support the concept that the Root ZX is a useful, versatile, and accurate device for the determination of canal lengths over a wide range of irrigants commonly used in the practice of endodontics.
Collapse
Affiliation(s)
- J A Jenkins
- Advanced Education Program, University of Texas Health Science Center at San Antonio, 78229-3900, USA
| | | | | | | |
Collapse
|
16
|
Abstract
This study was designed to compare pH changes at the cervical and apical surfaces of root dentin after canal obturation with calcium oxide or calcium hydroxide pastes. The effect of the exposure to CO2 on the pH at the root surface also was assessed for both materials. Thirty-six extracted human canines were selected and instrumented. Wells 1 mm deep x 1.5 mm in diameter were drilled in the cervical and apical regions of the buccal root surface. The teeth were randomly divided into two groups and obturated with either calcium hydroxide or calcium oxide. pH was measured in the cervical and apical wells at varying time intervals until 48 days posttreatment. After pH measurement on day 48 the vials were flushed with CO2 and the pH measured again at days 53 and 68. The results indicated a similar pattern of pH increase after treatment with either calcium oxide or calcium hydroxide. pH dropped significantly after exposure to CO2 in both groups. This study demonstrated that hydroxyl ions produced when calcium oxide reacts with water diffuse through the dentinal tubules to the surface of the root in a manner similar to hydroxyl ions from calcium hydroxide.
Collapse
Affiliation(s)
- M Miñana
- Department of Periodontics, University of Texas Health Science Center, San Antonio, 78284-7892, USA
| | | | | |
Collapse
|
17
|
Abstract
The purpose of this study was to determine the effect of ultrasonic vibration on the force required to remove prefabricated posts. Ninety-six extracted human canines were divided into eight groups, which were prepared and obturated with gutta-percha and either a eugenol-containing (Roth's 801 Elite) or eugenol-free (AH26) sealer. Titanium #6 Parapost XH posts were cemented with either zinc phosphate or Panavia 21 resin cement. One half of the sample was subjected to ultrasonic vibration for 16 min at the post-dentin interface, whereas the other half received no vibration (controls). Each combination of sealer, cement, and vibration status was subjected to tensile load to failure using an Instron testing machine. Posts cemented in teeth obturated with gutta-percha and AH26 sealer demonstrated significantly greater resistance to dislodgement, compared with teeth obturated with gutta-percha and Roth's 801 Elite sealer. There was no statistical difference in retention of posts cemented with either zinc phosphate or Panavia 21, regardless of the sealer used. Additionally ultrasonic vibration increased post retention for both cements.
Collapse
Affiliation(s)
- B E Bergeron
- Department of Endodontics, Wilford Hall USAF Medical Center, Lackland Air Force Base, TX, USA
| | | | | | | |
Collapse
|
18
|
King JC, Black RE, Doyle MP, Fritsche KL, Halbrook BH, Levander OA, Meydani SN, Walker WA, Woteki CE. Foodborne illnesses and nutritional status: a statement from an American Society for Nutritional Sciences Working Group. J Nutr 2000; 130:2613-7. [PMID: 11015498 DOI: 10.1093/jn/130.10.2613] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- J C King
- Western Human Nutrition Research Center, University of California, Davis, CA 95616, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
19
|
|
20
|
Nanthakumar NN, Fusunyan RD, Sanderson I, Walker WA. Inflammation in the developing human intestine: A possible pathophysiologic contribution to necrotizing enterocolitis. Proc Natl Acad Sci U S A 2000; 97:6043-8. [PMID: 10823949 PMCID: PMC18555 DOI: 10.1073/pnas.97.11.6043] [Citation(s) in RCA: 363] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Necrotizing enterocolitis (NEC), a major cause of morbidity and mortality in premature infants, occurs after the introduction of oral feedings in conjunction with initial bacterial colonization of the gut and is hypothesized to be due to an immature (inappropriate) enterocyte response to bacterial stimuli. To test this hypothesis, we compared the enterocyte IL-8 response to inflammatory stimuli [lipopolysaccharide (LPS) and IL-1beta] in immature vs. mature human small intestine. Initial in vitro studies comparing confluent Caco-2 cells, a model for mature human enterocytes, with a primary human fetal intestinal cell line (H4 cells) demonstrated that after inflammatory stimulation fetal cells secreted more IL-8 (LPS, 8-fold; IL-1beta, 20-fold) than Caco-2 cells. IL-8 mRNA activity in fetal compared to Caco-2 cells was proportionately increased by the same magnitude with both stimuli. To validate the in vitro observations, small intestinal organ cultures from fetuses vs. older children were exposed to LPS and IL-1beta. Again in human organ cultures from fetuses compared to older children, IL-8 secretion was greater (LPS, 2.5-fold; IL-1beta, 200-fold) and mRNA activity after stimulation was comparably higher, suggesting that increased transcription of the IL-8 gene may account for the excessive response. Using immunohistochemical staining to identify the cellular source of IL-8, activity was noted predominantly in villous and crypt epithelium but also in a few immunoresponsive lymphoid cells. The observation that immature human enterocytes react with excessive pro-inflammatory cytokine production after inflammatory stimulation may help in part explain why prematures exposed to initial colonizing bacteria develop necrotizing enterocolitis.
Collapse
Affiliation(s)
- N N Nanthakumar
- Developmental Gastroenterology Laboratory, Combined Program in Pediatric Gastroenterology and Nutrition, Massachusetts General Hospital, Department of Pediatrics, Harvard Medical School, 149 13th Street, Charlestown, MA 02129, USA
| | | | | | | |
Collapse
|
21
|
Walker WA. Role of nutrients and bacterial colonization in the development of intestinal host defense. J Pediatr Gastroenterol Nutr 2000; 30 Suppl 2:S2-7. [PMID: 10749395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
In this introduction to the supplement on the use of pre- and probiotics in the health and disease of pediatric patients, I have summarized factors affecting the initial colonization of the neonatal intestine. The term bacterial-epithelial cross-talk was defined, and examples of the enterocyte response to both pathologic and indigenous flora stimulation illustrated. Immaturities in the human neonatal intestinal response to bacteria and their toxins were reviewed in the context of the pathogenesis of age-specific, bacterial gastrointestinal infectious diseases. Finally, the importance of pre- and probiotics as measures to strengthen the neonate's intestinal host defenses in the prevention and treatment of specific age-related disease were considered.
Collapse
Affiliation(s)
- W A Walker
- Division of Nutrition, Harvard Medical School, Combined Program in Pediatric Gastroenterology and Nutrition, Children's Hospital, Boston, Massachusetts 02115, USA
| |
Collapse
|
22
|
Abstract
Root-end cavities have traditionally been prepared by means of small round or inverted cone burs in a micro-handpiece. Since sonically or ultrasonically driven microsurgical retrotips became commercially available in the early 1990s, this new technique of retrograde root canal instrumentation has been established as an essential adjunct in periradicular surgery. At first glance, the most relevant clinical advantages are the enhanced access to root ends in limited working space and the smaller osteotomy required for surgical access because of the various angled designs and small size of the retrotips. However, a number of experimental studies comparing root-end preparations made with microsurgical tips to those made with burs have demonstrated other advantages of this new technique, such as deeper cavities that follow the original path of the root canal more closely. The more centered root-end preparation also lessens the risk of lateral perforation. In addition, the geometry of the retrotip design does not require a beveled root-end resection for surgical access thus decreasing the number of exposed dentinal tubules. A controversial issue of sonic or ultrasonic root-end preparation is the formation of cracks or microfractures, and its implication on healing success. The present paper reviews experimental and clinical studies about the use of microsurgical retrotips in periradicular surgery and discusses many issues raised in previous papers.
Collapse
Affiliation(s)
- T von Arx
- Department of Periodontics, University of Texas Health Science Center at San Antonio, Texas, USA
| | | |
Collapse
|
23
|
Abstract
Bacterial toxin interaction with the intestinal epithelium is regulated developmentally as well as by nutritional factors. It is the binding of bacterial toxins to the epithelium followed by several events that forms the basis of infantile diarrhea, a leading cause of morbidity and mortality world-wide. There has been increasing interest in bacterial toxin interaction with the enterocyte, postreceptor events that follow and the effect of developmental regulation on necrotizing enterocolitis. Diet and environmental factors can provide a major influence on bacterial-enterocyte interaction. Particularly important is the role of breast milk and its constituents, as well as probiotics, in this regard. The purpose of this review is to provide a brief overview on this complex interaction.
Collapse
Affiliation(s)
- U Shah
- Harvard Medical School, Pediatric Gastroenterology and Nutrition, Massachusetts General Hospital and Children's Hospital, Boston, USA
| | | |
Collapse
|
24
|
Walker WA. What is the role of nucleotides and polyamines in breast milk? Acta Paediatr 1999; 88:1313-5. [PMID: 10626512 DOI: 10.1080/080352599750029989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- W A Walker
- Combined Program in Pediatric Gastroenterology and Nutrition, Harvard Medical School, Boston, MA, USA.
| |
Collapse
|
25
|
Abstract
This study evaluated the sectional gutta-percha obturation technique advocated by Lightspeed Technology, Inc. Single relatively straight-canaled teeth were prepared with rotary instruments and divided into three groups. Groups A and B served as controls and were obturated using laterally condensed gutta-percha and either Roth's 801 or Ketac-Endo sealer. Group C was obturated using the Lightspeed technique that included placement of a 5-mm apical section of gutta-percha, followed by backfill with Ketac-Endo sealer and a single gutta-percha cone. All teeth were suspended in India ink for 14 days then cleared. Four additional teeth, which were obturated as in group C then sectioned, revealed a tightly adapted apical section of gutta-percha with a very thin layer of sealer. However, voids were noted in the middle and coronal areas. There was no significant difference in apical microleakage among the three groups. The sectional method was significantly faster than lateral condensation and seems to offer promise as an effective obturation method.
Collapse
Affiliation(s)
- M D Santos
- Department of Endodontics, Wilford Hall Medical Center, Lackland AFB, TX, USA
| | | | | |
Collapse
|
26
|
Abstract
Not only does breast milk provides an ideal nutrient composition for the newborn, but it also contains a variety of substances that may actively influence growth and development of the infant and stimulate neonatal protection against gastrointestinal diseases. Hormones, growth factors, cytokines and even whole cells are present in breast milk and act to establish biochemical and immunological communication between mother and child. In addition, milk nutrients such as nucleotides, glutamine and lactoferrin have been shown to influence gastrointestinal development and host defense. The unique properties of milk as a mediator of biochemical messages will be presented and the clinical significance of breastfeeding in the prevention of neonatal gastrointestinal diseases will be discussed.
Collapse
Affiliation(s)
- K M Bernt
- Combined Program of Pediatric Gastroenterology and Nutrition, Massachusetts General Hospital, Boston 02115, USA
| | | |
Collapse
|
27
|
Abstract
This study evaluated the sealing ability of fast and regular set Super-EBA with different powder-to-liquid ratios as a root-end filling material. Fifty extracted maxillary central incisors were uniformly cleaned and shaped using a crown-down technique with Gates-Glidden drills and Profile series 29.04 taper rotary instruments. After root-end resection and ultrasonic preparation, 48 root sections were randomly assigned to 4 groups of 12 teeth each and filled with a thick or thin mix of fast or regular set Super-EBA. Fast and regular set Super-EBA were mixed to a thick (1 scoop powder:1 drop liquid) or a thin (1 scoop powder:2 drops liquid) consistency. Positive and negative controls were used. Microleakage was assessed at 24 h, 72 h, 1 wk, 2 wk, 4 wk, 6 wk, and 8 wk using a fluid filtration system. There were no significant differences in the microleakage measured for any group at any of the time points evaluated. These results suggest that either fast or regular set Super-EBA mixed to various consistencies may be acceptable for root-end filling.
Collapse
Affiliation(s)
- J M Yaccino
- Department of Endodontics, Wilford Hall Medical Center, Lackland AFB, TX 78284-7892, USA
| | | | | | | |
Collapse
|
28
|
Abstract
BACKGROUND Mineral trioxide aggregate, or MTA, is a new material developed for endodontics that appears to be a significant improvement over other materials for procedures in bone. It is the first restorative material that consistently allows for the overgrowth of cementum, and it may facilitate the regeneration of the periodontal ligament. CASE DESCRIPTION The authors present five cases in which MTA was used to manage clinical problems. These included vertical root fracture, apexification, perforation repair and repair of a resorptive defect. In each case, MTA allowed bone healing and elimination of clinical symptoms. CLINICAL IMPLICATIONS Materials such as zinc oxide-eugenol cement and resin composite have been used in the past to repair root defects, but their use resulted in the formation of fibrous connective tissue adjacent to the bone. Because it allows the overgrowth of cementum and periodontal ligament, MTA may be an ideal material for certain endodontic procedures.
Collapse
Affiliation(s)
- R S Schwartz
- U.S. Air Force, Dental Corps, Elmendorf Air Force Base, Alaska, USA
| | | | | | | |
Collapse
|
29
|
Siafakas CG, Anatolitou F, Fusunyan RD, Walker WA, Sanderson IR. Vascular endothelial growth factor (VEGF) is present in human breast milk and its receptor is present on intestinal epithelial cells. Pediatr Res 1999; 45:652-7. [PMID: 10231859 DOI: 10.1203/00006450-199905010-00007] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
VEGF (vascular endothelial growth factor) is a multifunctional cytokine active on blood vessel cells. The present study measured VEGF in the aqueous phase of human milk and examined how the concentration varied with gestational age and the duration of lactation after birth. We hypothesized that VEGF-specific receptors were present on the apical surface of intestinal epithelial cells. The concentration of monomeric VEGF (containing 165 residues) measured by ELISA in the breast milk was 2 orders of magnitude greater than that measured in the serum of normal adults. The VEGF165 concentration in the first week of lactation was greater in the breast milk of mothers of full-term than in preterm babies (p < 0.05). The concentration in the breast milk of mothers of full-term infants decreased (p < 0.01) after the first week of lactation. Scatchard analysis of radioligand-receptor binding showed the presence of specific receptors for 125I-VEGF165 on the surface of Caco-2, an intestinal epithelial cell line, with a kd of 2.85 to 4 nM. Reverse transcriptase PCR of Caco-2 cell RNA showed mRNA for the VEGF receptor flt-1. In conclusion, VEGF is present in high concentrations in breast milk and binds to specific receptors on cells derived from intestinal epithelium.
Collapse
Affiliation(s)
- C G Siafakas
- Developmental Gastroenterology Laboratory, Harvard Clinical Nutrition Research Center, Massachusetts General Hospital, Boston, USA
| | | | | | | | | |
Collapse
|
30
|
Walker WA. Should the Journal of Pediatric Gastroenterology and Nutrition participate in politically sensitive debates? J Pediatr Gastroenterol Nutr 1999; 28:459. [PMID: 10328116 DOI: 10.1097/00005176-199905000-00002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
|
31
|
Dai D, Walker WA. Protective nutrients and bacterial colonization in the immature human gut. Adv Pediatr 1999; 46:353-82. [PMID: 10645469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
The normal human microflora is a complex ecosystem that is in part dependent on enteric nutrients for establishing colonization. The gut microbiota are important to the host with regard to metabolic functions and resistance to bacterial infections. At birth, bacterial colonization of a previously germ-free human gut begins. Diet and environmental conditions can influence this ecosystem. A breast-fed, full-term infant has a preferred intestine microbiota in which bifidobacteria predominate over potentially harmful bacteria, whereas in formula-fed infants, coliforms, enterococci, and bacteroides predominate. The pattern of bacterial colonization in the premature neonatal gut is different from that in the healthy, full-term infant gut. Those infants requiring intensive care acquire intestinal organisms slowly, and the establishment of bifidobacterial flora is retarded. A delayed bacterial colonization of the gut with a limited number of bacterial species tends to be virulent. Bacterial overgrowth is one of the major factors that promote bacterial translocation. The aberrant colonization of the premature infant may contribute to the development of necrotizing enterocolitis. Breast-feeding protects infants against infection. Oligo-saccharides and glycoconjugates, natural components in human milk, may prevent intestinal attachment of enteropathogens by acting as receptor homologues. Probiotics and prebiotics modulate the composition of the human intestinal microflora to the benefit of the host. These beneficial effects may result in the suppression of harmful microorganisms, the stimulation of bifidobacterial growth, or both. In the future, control and manipulation of the bacterial colonization in the neonatal gut may be a new approach to the prevention and treatment of intestinal infectious diseases of various etiologies.
Collapse
Affiliation(s)
- D Dai
- Shanghai Institute for Pediatric Research, Shanghai Second Medical University, China
| | | |
Collapse
|
32
|
Dai D, Walker WA. Role of bacterial colonization in neonatal necrotizing enterocolitis and its prevention. Zhonghua Min Guo Xiao Er Ke Yi Xue Hui Za Zhi 1998; 39:357-65. [PMID: 9926507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
Necrotizing enterocolitis (NEC) is the most common gastrointestinal emergency in premature infants. A major component of the pathophysiology of NEC is the nature of the interaction of bacteria with the premature gut. Intestine microflora are important to the host in resistance to bacterial infections. Diet and environmental conditions can influence this ecosystem. A breast-fed full-term infant has a preferred intestine microbiota in which bifidobacteria predominate over the potentially harmful bacteria, whereas in formula-fed infants coliforms, enterococci and bacteroides predominate. The pattern of bacterial colonization in the premature neonate gut is quite different from that in the gut of the healthy full-term infant. Those infants requiring intensive care acquire intestinal organisms slowly, and the establishment of bifidobacterial flora is retarded. A delayed bacterial colonization of the gut with a limited number of bacterial species tends to be virulent. Bacterial overgrowth is one of major factors promoting bacterial translocation. The aberrant colonization of the premature infant may contribute to the development of NEC. Breast feeding protects infants against NEC. Oligosaccharides and glycoconjugates, natural components in human milk, may prevent intestinal attachment of enteropathogens by acting as receptor homologues. Probiotics and prebiotics modulate the composition of human intestine microflora to the benefit of the host. The beneficial effects may result in the suppression of colonization of harmful microoganisms and/or the stimulation of bifidobacterial growth. In the future, control and manipulation of bacterial colonization in the neonate gut may be a new approach to the prevention and treatment of bacterial intestinal disease of various etiologies.
Collapse
Affiliation(s)
- D Dai
- Shanghai Institute for Pediatric Research, Shanghai Second Medical University, China
| | | |
Collapse
|
33
|
Abstract
This study compared the sealing ability of TERM as an interim restoration for the "walking bleach" technique when using either sodium perborate/water or sodium perborate/superoxol. Thirty-three extracted maxillary premolars were restored with TERM after placing either a cotton pellet (control), a paste of sodium perborate and water, or a paste of sodium perborate and superoxol in the chamber. Microleakage was assessed at 24 h, 8 days, and 15 days using a fluid filtration method. Statistical analysis revealed both "walking bleach" groups had significantly higher numbers of teeth demonstrating microleakage than the control group. There was no statistically significant difference in microleakage between the two "walking bleach" groups. The results of this study indicated that the temporary restorative material, TERM, provided an unsatisfactory seal when used with either walking bleach technique. When used over a cotton pellet, TERM provided an excellent seal.
Collapse
Affiliation(s)
- R M Waite
- Department of Endodontics, Wilford Hall Medical Center, Lackland AFB, TX, USA
| | | | | |
Collapse
|
34
|
Affiliation(s)
- W A Walker
- Combined Program in Pediatric Gastroenterology and Nutrition, Massachusetts General Hospital, Boston, USA
| |
Collapse
|
35
|
Abstract
One hundred randomly selected mandibular incisors were examined to assess the prevalence and location of two canals and to describe the canal anatomy that may be encountered during apical surgery. Sections of the root were cut at 1, 2, and 3 mm from the apex, simulating a 20-degree beveled surgical resection. The sections were digitally imaged at x 50 magnification, and canal dimensions were measured using imaging software. The prevalence of two canals was 2% at 1 mm, 0% at 2 mm, and 1% at 3 mm. At these levels in the roots, the canal was rarely divided by hard tooth structure. An isthmus of tissue was present 20% of the time at 1 mm, 30% at 2 mm, and 55% at 3 mm. Four distinct canal types were noted: (i) round, (ii) oval, (iii) long oval, and (iv) ribbon. In 75% of the teeth, the canal shapes varied from one level to the next. The more coronally the root-end resection was made, the more elongated the canal tended to become.
Collapse
Affiliation(s)
- M J Mauger
- Department of Endodontics, Wilford Hall USAF Medical Center, Lackland Air Force Base, TX 78236-5300, USA
| | | | | |
Collapse
|
36
|
Abstract
Resin cements are sometimes recommended to enhance the retention of posts in endodontically treated teeth. Many sealer cements used in endodontics contain eugenol, however, which has been shown to inhibit the polymerization of resins. The purpose of this study was to evaluate the effects of a eugenol and a noneugenol sealer cement on the retention of posts. Sixty extracted canines were divided equally into four groups. Each tooth received conventional endodontic therapy and was prepared to receive a post. Two sealer cements were used in obturation: one contained eugenol and one was eugenol-free. The posts were cemented with either zinc phosphate cement or resin cement. Each combination of sealer and post cement was tested for retention on an Instron testing machine. The type of sealer used had no effect on post retention with either cement. Post retention was significantly greater with the zinc phosphate cement than the resin cement.
Collapse
Affiliation(s)
- R S Schwartz
- Department of Endodontics, University of Texas Health Science Center at San Antonio, School of Dentistry 78284, USA
| | | | | |
Collapse
|
37
|
Abstract
One hundred single-rooted teeth were instrumented with Lightspeed, Profile .04 Taper Series 29, and NT McXIM instruments according to the recommendations of the manufacturers, and Flex-R files using the balanced force technique. Groups were comparable with respect to average curvature, canal length, and major and minor foramen size. A standard amount of irrigant was used for each tooth. Apically extruded debris and irrigant were collected and weighed. Debris was desiccated before being weighed. There were no statistically significant differences among the four groups with respect to total extruded debris. The amount of extruded debris was positively correlated with the amount of irrigant extruded. Factors such as canal length, curvature, and foramen size did not affect the amount of debris extruded.
Collapse
Affiliation(s)
- R E Hinrichs
- Department of Endodontics, Wilford Hall Medical Center, Lackland AFB, TX., USA
| | | | | |
Collapse
|
38
|
Walker WA. The practice of American pediatric gastroenterology in the next millennium. J Pediatr Gastroenterol Nutr 1998; 26:116-8. [PMID: 9443130 DOI: 10.1097/00005176-199801000-00019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
|
39
|
Furlano RI, Walker WA. Immaturity of gastrointestinal host defense in newborns and gastrointestinal disease states. Adv Pediatr 1998; 45:201-22. [PMID: 9742303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Not only is the gastrointestinal tract the largest immune organ in the body, but it also contains one of the most important and interesting immunologic compartments. Host protection against pathogens and injurious agents by the gastrointestinal tract is essential for an individual's survival. The intestinal mucosal immune system, which is linked with other mucosal surfaces and together represents the common mucosal immune system, prevents the passage of potentially harmful antigens and pathogens into the systemic circulation of the host. In a healthy host, antigens crossing the mucosal barrier in physiologic quantities evoke the appropriate immune response, which includes polymeric IgA antibody production to the antigen and systemic tolerance.
Collapse
Affiliation(s)
- R I Furlano
- University of Basel School of Medicine, Basel, Switzerland
| | | |
Collapse
|
40
|
Abstract
The purpose of this study was to evaluate the effect of modified and non-modified tip designs of both stainless steel and nickel-titanium endodontic hand files on root canal preparation. Root canals of mesial roots of extracted mandibular molars were prepared using a quarter-turn-pull technique. The experimental design permitted comparison of the effects of nickel-titanium alloy construction or file tip modification alone, with effects when these two factors were incorporated into a single file design. Transportation, centering ratio, and dentin removal were evaluated using a modified Bramante technique. Nickel-titanium files, regardless of tip design, remained significantly more centered and demonstrated less apical transportation than stainless steel files at size 25. When instrumentation was continued to size 40 apically with step-back, there were no significant differences in transportation in the apical or coronal sections. However, during instrumentation to size 40 with step-back, the combination of modified tip and nickel-titanium alloy produced significantly more transportation and dentin removal, as well as greater deviation from the center at the mid-root level than did other file designs. Thus, of the file design parameters evaluated in this study, construction from nickel-titanium was most important in defining canal configuration at small file sizes in the apical region. Although the combination of nickel-titanium and modified tip design resulted in more transportation at larger file sizes in the midroot region, such alterations in canal configuration may be of little importance clinically. Nonetheless, it is suggested that other factors, such as tactile sensation and instrumentation technique, should be considered as important as the type of alloy or tip design.
Collapse
Affiliation(s)
- W G Kuhn
- Research Division, Department of Endodontics, University of Texas Health Science Center at San Antonio 78284-7892, USA
| | | | | | | |
Collapse
|
41
|
Harkacz OM, Carnes DL, Walker WA. Determination of periodontal ligament cell viability in the oral rehydration fluid Gatorade and milks of varying fat content. J Endod 1997; 23:687-90. [PMID: 9587309 DOI: 10.1016/s0099-2399(97)80402-5] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The purpose of this study was twofold: 1) to determine if the oral rehydration fluid Gatorade could serve as a suitable temporary storage medium for maintenance of periodontal ligament (PDL) cell viability on avulsed teeth and 2) to determine if fat content is related to maintenance of cell viability when milk is used as the temporary storage medium. PDL cells were cultured from extracted human teeth then incubated over timed intervals from 15 to 210 min in the oral rehydration fluid Gatorade, milks of varying fat content, and saliva. Dulbeco's Modified Eagles Medium served as the positive control while tap water served as the negative control. Cell viability was determined using a colorimetric assay that used Cell Proliferation Reagent WST-1. Results using Gatorade yielded cell viability data similar to the negative control, tap water, indicating that this oral rehydration fluid was not suitable as a temporary storage medium for the avulsed tooth. However, the fat content of milk was found to have an effect on cell viability, suggesting that milks with lower fat content may be more appropriate for maintaining PDL cell viability than milks with higher fat content.
Collapse
Affiliation(s)
- O M Harkacz
- Department of Endodontics, Wilford Hall Medical Center, Lackland Air Force Base, TX, USA
| | | | | |
Collapse
|
42
|
Walker WA. Breast milk and the prevention of neonatal and preterm gastrointestinal disease states: a new perspective. Zhonghua Min Guo Xiao Er Ke Yi Xue Hui Za Zhi 1997; 38:321-31. [PMID: 9401174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In this review of the protective properties of human breast milk, a new perspective is taken to underscore the passive and active protection properties of breast milk in providing specific protection against selective gastrointestinal disease affecting the neonate and preterm infant. The normal protective properties of the gastrointestinal epithelial barrier (immunologic and nonimmunologic) are considered as is the development of barriers to antigen absorption in the immature infant human intestine as a background for considering three accelerated gastrointestinal diseases-necrotizing enterocolitis, intestinal allergy, and bacterial gastroenteritis. In each of these conditions, the developmental protective defect is considered and the role of breast milk plays in filling the protective void discussed. Besides considering passive protection of breast milk including the new roles assigned to nutrients such as lactoferrin and nucleotides, and importance of active substances in breast milk such as growth factors, cytokines and hormones are discussed in the context of actively stimulating the infant's own intestinal defenses to function as a protective barrier. Future studies at the cellular and molecular level should be helpful in designing both preventative and treatment strategies to deal with these diseases.
Collapse
|
43
|
McCoy DW, Weiman DS, Pate JW, Fabian TC, Walker WA. Subclavian artery injuries. Am Surg 1997; 63:761-4. [PMID: 9290516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Thirty-two consecutive patients with subclavian artery injuries were evaluated to assess the mechanism of injury, types of repair, and results. In this series, most wounds were from firearms. Although the mortality was high (19%), most patients had the vessel repaired successfully. Associated injuries, especially to neural structures, led to significant morbidity. Principles used in dealing with these injuries should be 1) proximal and distal control prior to exposing the injury site, 2) reestablishing distal circulation through primary repair or graft placement, and 3) identifying and treating associated injuries.
Collapse
Affiliation(s)
- D W McCoy
- Department of Surgery, University of Tennessee-Memphis College of Medicine 38163, USA
| | | | | | | | | |
Collapse
|
44
|
Oguchi S, Shinohara K, Yamashiro Y, Walker WA, Sanderson IR. Growth factors in breast milk and their effect on gastrointestinal development. Zhonghua Min Guo Xiao Er Ke Yi Xue Hui Za Zhi 1997; 38:332-7. [PMID: 9401175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Breast milk contains various biologically active factors including, hormones, peptide growth factors, and cytokines. Epidermal growth factor (EGF) and insulinlike growth factor-I (IGF-I) are two of the major milk-derived peptide growth factors. Colostrum contains higher levels of these growth factors than mature milk does, and, these factors are relatively resistant to proteolysis and stable in the G-I tract. There are specific receptors found in G-I mucosa. Luminal EGF and IGF-I stimulate growth and development of gastrointestinal tract. Intestinal epithelial Caco-2 cells are a good model for studying physiological roles of exogenous growth factors in the G-I development. Effect of EGF and IGF-I on proliferation, differentiation, and IGF-binding protein (IGFBP) production of intestinal Caco-2 cells were studied. Both EGF and IGF-I increased cell proliferation in dose dependent manner. The number of IGF-I receptors on Caco-2 cells increased after differentiation, in contrast to EGF binding which was reported to decrease. Caco-2 cells produced at least three IGFBPs, namely IGFBP-2, -3, and -4. The profile of these IGFBPs varied with differentiation. Secretion of IGFBP-2 and -3 increased with differentiation, but IGFBP-4 diminished. IGF-I stimulated mainly IGFBP-3 production, while EGF stimulated predominantly IGFBP-4. The effects of IGF-I and EGF on IGFBP secretion diminished with increasing cell differentiation. Thus, the interaction between intestinal epithelial cells and extrinsic growth factors are complex and the stage of differentiation is an important determinant of this phenomenon.
Collapse
Affiliation(s)
- S Oguchi
- Department of Pediatrics, Juntendo University School of Medicine, Tokyo, Japan
| | | | | | | | | |
Collapse
|
45
|
Forchielli ML, Lo CW, Richardson D, Gura K, Walker WA, Tonelli E. Central venous line related bacteremia during total parenteral nutrition and/or chemotherapy infusions in children. Ann Ig 1997; 9:35-40. [PMID: 9284587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- M L Forchielli
- Combined Program in Gastroenterology and Nutrition and Pharmacy, Children's Hospital, Boston, USA
| | | | | | | | | | | |
Collapse
|
46
|
Abstract
Sealer placement techniques have not been examined in teeth with curved canals prepared with Lightspeed instruments. Three traditional methods of placing sealer were studied, using 45 extracted human single-rooted teeth, divided into 3 groups of 15. Root canal preparations were made with Light-speed nickel-titanium, engine-driven instruments. AH26 sealer was applied with either K-file, lentulo spiral, or master gutta-percha cone. Radiographs were taken after sealer placement and analyzed for amount of canal sealer fill. The teeth were then obturated with laterally condensed gutta-percha, chemically cleared, photographed, and analyzed for total canal wall sealer coverage. The results showed a statistically significant difference in canal sealer fill among the three groups before obturation, but there was no statistical difference in canal wall coverage among the three groups after obturation. None of the examined methods exceeded an average of 62.5% wall coverage of sealer after obturation. This suggests that complete wall coverage after obturation may not be possible.
Collapse
Affiliation(s)
- M C Hall
- Department of Endodontics, Wilford Hall USAF Medical Center, Lackland Air Force Base, TX, USA
| | | | | | | |
Collapse
|
47
|
Walker WA. Exogenous nucleotides and gastrointestinal immunity. Transplant Proc 1996; 28:2438-41. [PMID: 8907886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- W A Walker
- Harvard Medical School, Combined Program in Pediatric Gastroenterology and Nutrition, Massachusetts General Hospital & Children's Hospital, Boston, USA
| |
Collapse
|
48
|
Abstract
During an 8-year period between 1985 and 1993, twelve patients were treated with combined gunshot wounds to the trachea and esophagus. All patients survived, but there were complications, including one tracheoesophageal fistula. Combined injuries of the trachea and esophagus should be repaired primarily, and drains do not necessarily have to be placed. The benefit of a muscle flap placed between the repairs was not confirmed in this series. Complications should be recognized early and treated aggressively to minimize damage to the airway.
Collapse
Affiliation(s)
- D S Weiman
- Department of Surgery, University of Tennessee College of Medicine, 956 Court Avenue, G 212, Memphis, Tennessee 38163-2116, U.S.A
| | | | | | | | | |
Collapse
|
49
|
Sanderson IR, Ezzell RM, Kedinger M, Erlanger M, Xu ZX, Pringault E, Leon-Robine S, Louvard D, Walker WA. Human fetal enterocytes in vitro: modulation of the phenotype by extracellular matrix. Proc Natl Acad Sci U S A 1996; 93:7717-22. [PMID: 8755542 PMCID: PMC38813 DOI: 10.1073/pnas.93.15.7717] [Citation(s) in RCA: 108] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The differentiation of small intestinal epithelial cells may require stimulation by microenvironmental factors in vivo. In this study, the effects of mesenchymal and luminal elements in nonmalignant epithelia] cells isolated from the human fetus were studied in vitro. Enterocytes from the human fetus were cultured and microenvironmental factors were added in stages, each stage more closely approximating the microenvironment in vivo. Four stages were examined: epithelial cells derived on plastic from intestinal culture and grown as a cell clone, the same cells grown on connective tissue support, primary epithelial explants grown on fibroblasts with a laminin base, and primary epithelial explants grown on fibroblasts and laminin with n-butyrate added to the incubation medium. The epithelial cell clone dedifferentiated when grown on plastic; however, the cells expressed cytokeratins and villin as evidence of their epithelial cell origin. Human connective tissue matrix from Engelbreth-Holm-Swarm sarcoma cells (Matrigel) modulated their phenotype: alkaline phosphatase activity increased, microvilli developed on their apical surface, and the profile of insulin-like growth factor binding proteins resembled that secreted by differentiated enterocytes. Epithelial cells taken directly from the human fetus as primary cultures and grown as explants on fibroblasts and laminin expressed greater specific enzyme activities in brush border membrane fractions than the cell clone. These activities were enhanced by the luminal molecule sodium butyrate. Thus the sequential addition of connective tissue and luminal molecules to nonmalignant epithelia] cells in vitro induces a spectrum of changes in the epithelial cell phenotype toward full differentiation.
Collapse
Affiliation(s)
- I R Sanderson
- Developmental Gastroenterology Laboratory, Harvard Clinical Nutrition Research Center, Massachusetts General Hospital, Boston 02129-2060, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
50
|
Sanderson IR, Xu Z, Chu SW, Xie QY, Levine LJ, Walker WA. Developmental differences in the expression of the cholera toxin sensitive subunit (Gs alpha) of adenylate cyclase in the rat small intestine. Gut 1996; 38:853-8. [PMID: 8984023 PMCID: PMC1383192 DOI: 10.1136/gut.38.6.853] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND The stimulatory guanosine triphosphate (GTP) binding protein alpha subunit (Gs alpha) of adenylate cyclase is the target protein for cholera toxin. AIMS/METHODS The expression of this signal transducer was analysed in the small intestine of developing rats by RNA transfer (northern blot) analysis by immunoblotting, and by ADP-ribosylation of membrane proteins. RESULTS Intestinal Gs alpha mRNA (about 1.9 kb) was increased in the neonate compared with the adult rat. Two isoforms of Gs alpha proteins, a 45,000 and a 52,000 form, were expressed in the small intestinal epithelial cell and both were ADP-ribosylated by cholera toxin. A significant increase in the larger isoform (52,000) and in its ribosylation was noted in the 2 week old suckling compared with post-weaned older animals. The protein content or ribosylation of the smaller form (45,000) did not significantly change with age. CONCLUSION These data show that a developmental decline of intestinal Gs alpha expression seems to be, in part, regulated at the mRNA level. An increased Gs alpha expression in the immature intestine may help to explain a previously reported, dose dependent increased adenylate cyclase response and an increase in fluid secretion to cholera toxin in neonates compared with adults.
Collapse
Affiliation(s)
- I R Sanderson
- Developmental Gastroenterology Laboratory, Massachusetts General Hospital and Harvard Medical School, Boston, USA
| | | | | | | | | | | |
Collapse
|