Biomedical subjects

M Wasa

Publications and source records attributed to M Wasa.

48 records · Page 3Linked to original sources

PubMedDate not supplied

Experimental study of hub contamination: effect of a new connection device: the I system.

Experimental studies of hub contamination of intravenous catheters were done comparing the standard connection method (Luer-Lock connector) with a newly invented connection method (I system). Immersion of the connection sites into a bacteria-containing solution showed no bacterial contamination of the medium in any tubing. The second experiment investigated whether bacterial contamination would occur during a tubing change procedure. A high incidence of bacterial contamination was seen with the Luer-Lock connector, but no bacterial contamination occurred with the I system. These experiments suggest that the use of Luer-Lock connectors is associated with a high risk of bacterial contamination during tubing change, but the I system can prevent contamination during tubing change, which cannot be avoided with Luer-Lock connector.

Bacteria↗

PubMedDate not supplied

Prevention of catheter-related sepsis during parenteral nutrition: effect of a new connection device.

A prospective study was carried out to determine the clinical effect of a newly devised catheter connection method (I system) and piggyback access system. Previous studies have demonstrated that the I system avoided bacterial contamination in vitro during tubing change that Luer-Lock connectors did not. The purpose of this study was to investigate the ability of this device coupled with a new closed-system piggyback technique for multipurpose access to reduce catheter-related sepsis in clinical practice. Two hundred and thirty patients receiving total parenteral nutrition were divided into two groups. Group I (n = 106) used the I system connector and group L (n = 124) used a Luer-Lock connector. Catheters in both groups were used for multipurpose access for infusion and blood sampling. In group L, a three-way stopcock and/or pig-gyback system was used for multiple access. In group I, a newly designed closed-system piggyback was used. The incidence of catheter-related sepsis was significantly lower in group I (1.89%/catheter) than in group L (12.10%/catheter) (p < .01, chi 2 analysis), and the average duration of use of each catheter was significantly longer in group I than in Group L (p < .01 by generalized Wilcoxon test). The results of this clinical study suggest that the newly designed connection method and piggyback access system are able to reduce catheter-related sepsis.

Adolescent↗

PubMedDate not supplied

Copper deficiency with pancytopenia during total parenteral nutrition.

Anemia and neutropenia are commonly observed hematologic changes in patients with copper (Cu) deficiency, but thrombocytopenia is rarely found. A-69-year-old patient with postoperative small-bowel obstruction underwent laparotomy three times. Because of persistent obstruction, nasoduodenal suction was continued and total parenteral nutrition was instituted. Fifteen months after the initiation of total parenteral nutrition, the patient gradually developed pancytopenia (red blood cell count 222 x 10(4)/mm3, neutrophil count 1254/mm3, and platelet count 9.2 x 10(4)/mm3). The serum Cu level was 10 micrograms/dL and the serum ceruloplasmin level was less than 5 mg/dL. After 2 weeks of Cu supplementation in a daily dose of 20 mumol, the serum Cu level increased to 81 micrograms/dL and the serum ceruloplasmin level to 20 mg/dL. Hematologic values showed a dramatic response: red blood cell count increased to 362 x 10(4)/mm3, neutrophil count to 4819/mm3, and platelet count to 22.1 x 10(4)/mm3. The improvement of pancytopenia could be attributed to Cu supplementation. This is the first case report of Cu deficiency with pancytopenia during total parenteral nutrition.

Aged↗

PubMedDate not supplied

Total parenteral nutrition decreases luminal mucous gel and increases permeability of small intestine.

The distribution of fluorescein isothiocyanate dextran 70,000 (FITC-dextran) and mucous gel across the lumen of small intestine was observed as an investigation into the role of mucous gel on permeability in total parenteral nutrition (TPN). Thirty-two rats were randomly divided into two groups fed with either TPN or oral rat food. On day 4 or 7, FITC-dextran (750 mg/kg body weight) was given through the gastroduodenal tube. After 1 hour, blood samples were taken by aortic puncture to analyze plasma FITC-dextran by fluorescence spectrometry. Samples of small intestine with luminal contents were frozen and sectioned in a cryostat for fluorescence microscopy; the same sections were placed in a 0.2% celloidin solution for 3 minutes to preserve mucous gel and stained by periodic acid-Schiff reaction for light microscopy. The plasma level of FITC-dextran after 1 hour of this marker injection showed a significant increase (p < .01) in the TPN group compared with the rat food group on days 4 and 7. Morphologic findings on days 4 and 7 were similar in both the jejunum and ileum: The mucous gel filled the spaces between villi and FITC-dextran centered in the lumen in the rat food group, whereas the mucous gel decreased and FITC-dextran filled the spaces between villi in the TPN group. FITC-dextran and mucous gel showed complementary distributions in both groups. These data suggest that TPN decreases luminal mucous gel and increases permeability of small intestine in rats.

Animals↗

PubMedDate not supplied

Inhibition of pulmonary microvascular endothelial glutamine transport by glucocorticoids and endotoxin.

BACKGROUND: During septic states, the lungs produce increased amounts of glutamine, an event that is mediated by both endotoxin and glucocorticoid hormones and is presumed to be due to accelerated intracellular glutamine biosynthesis. Because enhanced net glutamine release in vivo could also be due to a decrease in cellular uptake, we assayed glutamine transport in cultured rat microvascular pulmonary endothelial cells. METHODS: The effect of Escherichia coli endotoxin (LPS, 1 microgram/mL), various cytokines, and dexamethasone (DEX, 0.1 mumol/L) on glutamine transport activity was studied in rat lung microvascular endothelial cells grown in varying glutamine concentrations (0, 0.1, 0.5, and 2 mmol/L). Experiments were also performed in cells treated with cycloheximide, actinomycin D, or chelerythrine chloride. RESULTS: More than 90% of glutamine transport was mediated by the Na+ -dependent transport system ASC. DEX and LPS inhibited endothelial glutamine uptake in a time- and dose-dependent manner, a response that was only observed with incubation medium contained the lower concentrations of glutamine. Neither DEX nor LPS altered transport activity in cells cultured in medium containing 2 mmol glutamine/L. There was no synergistic or additive effect when both compounds were added together. The cytokines tumor necrosis factor alpha, interleukin (IL) 1, IL-2, and IL-6 did not alter glutamine transport. both DEX and LPS inhibited glutamine transport by decreasing transporter maximal transport velocity (Vmax) without affecting transporter affinity (Km). Cycloheximide and actinomycin D abrogated the inhibition of transport activity that was observed in DEX- or LPS-treated cells, whereas the protein kinase C inhibitor chelerythrine chloride had no effect on either control or stimulated glutamine transport. CONCLUSIONS: These data suggest that DEX and LPS "down-regulate" glutamine uptake by lung microvascular endothelial cells by inducing the synthesis of an inhibitory protein that modulates the activity of the system ASC protein. This response in vitro appears to be influenced by the extracellular glutamine concentration. This decrease in microvascular endothelial glutamine transport may be one mechanism by which net lung glutamine release is enhanced during critical illness.

Animals↗

PubMedDate not supplied

Lipopolysaccharide and tumor necrosis factor stimulate lung microvascular arginine uptake, a response attenuated by dexamethasone.

BACKGROUND: Lipopolysaccharide (LPS), tumor necrosis factor-alpha, (TNF), and glucocorticoids can modulate endothelial nitric oxide (NO) production. L-Arginine is the exclusive precursor for NO biosynthesis, suggesting that NO generation and arginine transport are intimately linked. METHODS: To further study this relationship, we examined the effects of LPS, TNF, and dexamethasone (DEX) on arginine uptake by rat lung microvascular endothelial cells. The transport of radiolabeled arginine was assayed in confluent cells grown in 24-well plates. RESULTS: The bulk (> 90%) of arginine transport was mediated by the Na(+)-independent carriers System y+ and System b0,+. Arginine transport was stimulated independently by LPS and TNF, a response first observed at 10 hours. Together, both agents exerted an additive effect on carrier-mediated uptake. The LPS- and TNF-induced increase in arginine transport activity was blocked by cycloheximide and actinomycin D, indicating the requirement for RNA and protein synthesis. The enhancement in transport activity was primarily due to an increase in Systems y+ maximal transport capacity (Vmax) with no change in transporter affinity and little change in System b0,+ activity. Treatment of cells with dexamethasone inhibited arginine transport activity in a time- and dose-dependent manner, an event that was abrogated by both actinomycin D and cycloheximide. The combination of DEX and LPS and TNF abrogated each other's antagonistic effects. CONCLUSIONS: These data indicate that LPS and TNF additively stimulate arginine transport in lung microvascular endothelial cells via a pathway that requires de novo protein synthesis (possibly of the transporter protein itself) and that this response is attenuated by DEX.

Animals↗

PubMedDate not supplied

Developmental changes in distribution of the mucous gel layer and intestinal permeability in rat small intestine.

BACKGROUND: From the developmental aspects, the distribution of fluorescein isothiocyanate dextran 70,000 (FTTC-dextran) and mucous gel across the lumen of small intestine was observed as an investigation into the role of mucous gel on intestinal permeability. Furthermore, the effect of N-acetyl cysteine (NAC), a mucolytic agent, on intestinal permeability was examined. METHODS: In suckling and weaned rats, FTTC-dextran (750 mg/kg body wt) was gavage-fed. After 3 hours, blood samples were taken by cardiac puncture to analyze plasma FTTC-dextran by fluorescence spectrometry. Samples of small intestine with luminal contents were frozen and sectioned in a cryostat for fluorescence microscopy; the same sections were placed in a 0.2% celloidin solution to preserve mucous gel and were stained by periodic acid-Schiff reaction for light microscopy. In weaned rats, intestinal permeability was examined with different concentrations of intraluminally instilled NAC. RESULTS: The plasma level of FTTC-dextran showed a significant increase (p < .01) in suckling rats compared with the weaned rats. Morphologic findings were similar in both the jejunum and ileum: The spaces between villi were not entirely filled with mucus but filled with FTTC-dextran in suckling rats, whereas the spaces were filled with mucus and not filled with FTTC-dextran in weaned rats. Intestinal permeability in groups with NAC were significantly higher (p < .01) than that in group without NAC. CONCLUSIONS: These results suggest that an increase in the mucous gel layer that coats the epithelial lining according to the maturation of the gastrointestinal tract is one of the most important factors for a restriction in intestinal permeability.

Acetylcysteine↗

PubMedDate not supplied

Total parenteral nutrition increases uptake of latex beads by Peyer's patches.

BACKGROUND: Dysfunction of the intestinal barrier, as evidenced by increased intestinal permeability and bacterial translocation, has been reported under total parenteral nutrition (TPN). However, the role of Peyer's patches on the intestinal barrier in TPN is not well understood. We investigated whether TPN alters the uptake of microparticles by the follicle-associated epithelium of Peyer's patches. METHODS: Twenty rats were divided into two groups, a control group and a TPN group. Fluorescent polystyrene latex beads, 3.2 +/- 0.2 microns in diameter, were used as a probe for measuring the uptake by Peyer's patches. After 1 week of consuming either the control or TPN diet, rats were killed. On the day of killing, 0.1 mL of latex beads solution was injected into a 1-cm length of ileal loop, within 10 cm of the ileocecal valve. Samples were taken after 30 minutes of injection, sectioned by cryostat, and then viewed under a fluorescent microscope. Follicle-associated epithelial length and particles were counted using a confocal laser scanning microscope. The number of particles within each compartment was standardized per unit length of epithelium of Peyer's patches. RESULTS: Particle numbers within Peyer's patch dome of the TPN group were significantly increased compared with those of the control group (p < .01). CONCLUSIONS: These data suggest that dysfunction of the intestinal barrier in TPN might be associated with a change of uptake by Peyer's patches.

Animals↗

PubMedDate not supplied

Role of intestinal mucus on the uptake of latex beads by Peyer's patches and on their transport to mesenteric lymph nodes in rats.

BACKGROUND: The effects of N-acetylcysteine (NAC) as a mucolytic agent on the uptake of fluorescent polystyrene microparticles by Peyer's patches, on intestinal permeability, and on subsequent transport to mesenteric lymph nodes (MLNs) were investigated to establish the role of mucus gel layer in this process. METHODS: Twenty rats were divided into two groups: control (n = 10) and NAC (n = 10). Fluorescent polystyrene latex beads of 3.2+/-0.2 microm in diameter were used as a probe for measuring the previously mentioned parameters. The solution of latex beads (0.1 mL) was injected into a 2-cm length of ileal loop containing Peyer's patches, with 0.1 mL of saline (control group) or with 0.1 mL of NAC solution (NAC group) within 10 cm proximal from the ileocaecal valve. Intestinal loops, portal blood, and neighboring MLNs were taken within 1 hour of injection. Intestinal sections were stained by periodic acid-Schiff reagent. Peyer's patches and MLNs were analyzed for the count of particles by image analysis using a confocal laser scanning microscope. RESULTS: Morphologically, periodic acid-Schiff positive uniform mucus gel was present in front of Peyer's patches of the control group, and mucus gel layer was disrupted and noncontinuous in the NAC group. The number of particles within Peyer's patches and MLNs in the NAC group was significantly higher than that in the control group (p<.001). Intestinal permeability of latex beads in the NAC group was significantly higher than that in the control group (p<.001). CONCLUSIONS: These data suggest that the mucus gel layer located in front of Peyer's patches is one of the important factors for the uptake of noxious macromolecules, and this in turn plays a major role on small intestinal permeability and subsequent translocation to MLNs.

Acetylcysteine↗

PubMedDate not supplied

Alanyl-glutamine-supplemented parenteral nutrition increases luminal mucus gel and decreases permeability in the rat small intestine.

BACKGROUND: Effect of supplemental alanyl-glutamine in standard TPN (S-TPN) on luminal mucus gel and small intestinal permeability was investigated. METHODS: Thirty Sprague-Dawley rats were divided into group I (n = 10), receiving standard rat diet; group II (n = 10), receiving S-TPN; and group III (n = 10), receiving alanyl-glutamine-supplemented TPN for 1 week. After 1 week, fluorescein isothiocyanate (FITC)-dextran was injected into the small intestine of the rats, and they were killed. A small intestinal sample and portal blood were obtained for morphologic and functional analysis of mucus gel and intestinal permeability. RESULTS: In group II, thickness and optical density of mucus gel per millimeter serosal length of intestine were significantly lower than group I (p<.001) and were significantly higher in group III than in group II (p<.001). The number of goblet cells in the villi and in the crypt of the small intestine was significantly lower in group II than in group I (p<.001) and was significantly higher in group III than in group II (p<.001), with the exception of the villi of jejunum. Villous and crypt surface area per millimeter serosal length of intestine was significantly lower in group II than in group I (p<.001) and was significantly higher in group III than in group II (p<.001). Small intestinal permeability to FITC-dextran was significantly higher in group II than in group I (p<.001) and was significantly lower in group III than in group II (p<.001). Glucosamine synthetase level was significantly higher in group III than in group I and ileum of group II (p<.001). CONCLUSIONS: Alanyl-glutamine-supplemented TPN prevents a decrease in mucus gel and an increase in small intestinal permeability associated with S-TPN.

Animals↗

PubMedDate not supplied

Insulin-like growth factor-1 modulation of intestinal epithelial cell restitution.

After superficial intestinal injury, the mucosal integrity is reestablished by rapid migration of epithelial cells from the adjacent area in a process called restitution. Our previous study suggested that growth hormone improves intestinal healing in an experimental small bowel ulceration, mediated by insulin-like growth factor-1 (IGF-1). The aim of the present study was to assess the role of IGF-1 in mucosal epithelial restitution using an in vitro epithelial wound model. Wounds were established in confluent monolayers of the intestinal cell line, IEC-6. Migration was quantitated in the presence or absence of IGF-1 as the number of cells migrating across the wound edge. Proliferation was assessed by thymidine incorporation. IGF-1-enhanced epithelial cell migration by 2- to 2.5-fold after 12- and 24-hour treatment, respectively, the first step involved in gastrointestinal wound healing. Cell proliferation was significantly stimulated by IGF-1 as well. In addition, expression of transforming growth factor-beta (TGF-beta) mRNA was significantly enhanced in the wounded monolayers treated with IGF-1. IGF-1 receptor mRNA was found to be detectable throughout the gastrointestinal mucosa and in the intestinal epithelial cells. In conclusion, these findings suggest that IGF-1 plays an important role in reconstitution of intestinal epithelial integrity after mucosal injury.

Animals↗

PubMedDate not supplied

Long-term outcome of short bowel syndrome in adult and pediatric patients.

We reviewed 12 pediatric and 18 adult patients with short bowel syndrome (SBS) from Osaka University Hospital and compared clinical characteristics between them. The length of the residual small intestine ranged from 0 to 75 cm (mean 47 cm) in pediatric patients and from 0 to 150 cm (mean 47 cm) in adult patients. In all cases, total parenteral nutrition (TPN) was started immediately after surgery and was gradually replaced by enteral nutrition. Eight pediatric patients (67%) and 4 adult patients (22%) were weaned from TPN. Residual intestinal length in these patients ranged from 27 to 75 cm (mean 57 cm) in pediatric patients and 57 to 150 cm (mean 96 cm) in adult patients. Pediatric patients with residual small intestinal lengths of 0, 16, 25, and 45 cm were not weaned from TPN. None of the adult patients with residual small intestinal length less than 40 cm could achieve complete intestinal adaptation. Five adult patients died due to liver failure (2 cases), heart failure (2 cases), or pneumonia (1 case), whereas all pediatric patients survived. The average life span of indwelling central venous catheters was 511 days and 780 days, and the rate of catheter-related sepsis per 1000 catheter days was 0.73 and 0.48 in pediatric and adult patients, respectively. Plasma levels of arginine and citrulline in patients receiving TPN were significantly decreased compared with those in patients receiving TPN without SBS both in pediatric and adult patients (p < .01). These results indicate that pediatric and adult patients with SBS can survive with TPN and enteral nutrition. The minimum remaining intestinal length necessary for complete bowel adaptation is shorter for pediatric patients than adults, suggesting better bowel adaptation in pediatric patients.

Adaptation, Physiological↗