Abnormal Temporal Window of Integration in Auditory Sensory Memory in Schizophrenia.

Mismatch negativity (MMN) is automatically elicited by incoming sound deviation compared to the neural representation of preceding homogenous sounds stored in the brain's auditory sensory memory. This study aimed to assess time-functional deviation sensitivity in auditory sensory memory associated with a temporal window of integration (TWI) of 160-170 msec in patients with schizophrenia. To this end, we measured the magnetic counterpart of the MMN (MMNm) in 20 patients with schizophrenia on medication and 20 healthy age-matched adults as a control group responding to an omitted tone segment incorporated into a complex sound of 176 ms duration corresponding to the TWI duration. Overall, the magnitude of the MMNm was smaller in the patients with schizophrenia than in the healthy control group. The peak latency of the MMNm was prolonged in the latter omitted segments for both groups, but to a greater extent in patients with schizophrenia. These results indicate that deviation detection is impaired in the later part of the TWI, corresponding to the duration of auditory sensory memory in patients with schizophrenia. Thus, the specific impairment of MMN in response to duration deviants (duration MMN), as previously reported, might result from a damaged mechanism in the later part of the TWI of sensory memory, suggesting that a decline in sensory memory causes distorted perception or disturbances in cognitive function in patients with schizophrenia.

An ultrathin poly(L-lactic acid) nanosheet as a burn wound dressing for protection against bacterial infection.

Burn wounds are highly susceptible to bacterial infection due to impairment of the skin's integrity. Therefore, prevention of bacterial colonization/infection in the wound is crucial for the management of burns, including partial-thickness burn injuries. Although partial-thickness burn injuries still retain the potential for reepithelialization, the complication of wound infection severely impairs the reepithelialization even in such superficial burn injuries. We recently developed a biocompatible nanosheet consisting of poly(L-lactic acid) (PLLA). The PLLA nanosheets have many useful and advantageous biological properties for their application as a wound dressing, such as sufficient flexibility, transparency, and adhesiveness. We herein investigated the suitability of the PLLA nanosheets as a wound dressing for partial-thickness burn wounds in mice. The PLLA nanosheets tightly adhered to the wound without any adhesive agents. Although wound infection with Pseudomonas aeruginosa in the controls significantly impaired reepithelialization of burn wounds, dressing with the PLLA nanosheet markedly protected against bacterial wound infection, thereby improving wound healing in the mice receiving partial-thickness burn injuries. The PLLA nanosheet also showed a potent barrier ability for protecting against bacterial penetration in vitro. The ultrathin PLLA nanosheet may be applied as a protective dressing to reduce environmental contamination of bacteria in a partial-thickness burn wound.

Memory trace dependence on number of stimuli in magnetic mismatch negativity.

Mismatch negativity (MMN) reflects a comparison process between a deviant stimulus and the memory trace of standard stimuli. Although this memory mechanism has been investigated by many research studies, the development of memory representation still remains unclear. In this study, we focused on the development of sound trace underlying the MMN response. We measured the magnetic counterpart of MMN (MMNm) in detail, when the neural trace of the standard sound was developed in accordance with the number of standard stimuli. When the number of standard stimuli increased, MMNm latency significantly shortened and the MMNm amplitude showed no significant change. Thus, the developmental effects on memory trace may differ between MMNm amplitude and MMNm latency.

Reversal of parenteral nutrition-induced gut mucosal immunity impairment with small amounts of a complex enteral diet.

BACKGROUND: Although parenteral nutrition (PN) prevents progressive malnutrition, lack of enteral nutrition (EN) during PN leads to gut associated lymphoid tissue (GALT) atrophy and dysfunction. Administering a small amount of EN with PN reportedly prevents increases in intestinal permeability. However, its effects on GALT remain unclear. We analyzed the minimum amount of EN required to preserve gut immunity during PN. METHODS: Male Institute of Cancer Research mice underwent jugular vein catheter insertion and tube gastrostomy. They were randomized into four groups to receive isocaloric and isonitrogenous nutritional support with variable EN to PN ratios (EN 0, EN 33, EN 66, and EN 100). EN was provided with a complex enteral diet. After 5 days of feeding, the mice were killed and whole small intestines were harvested. GALT lymphocytes were isolated and counted. Their phenotypes were analyzed by flow cytometry. IgA levels of small intestinal washings were analyzed with enzyme-linked immunosorbent assay. RESULTS: Body weight changes did not differ between any two of the groups. Peyer's patch lymphocyte numbers increased in proportion to EN amount, whereas lamina propria lymphocyte numbers were significantly higher in the EN 100 than in the EN 0 group, with no marked increases in the EN 33 and EN 66 groups. Small intestinal IgA levels increased EN amount-dependently and reached a plateau at EN 66. CONCLUSIONS: A small amount of EN partially reverses PN-induced GALT changes, suggesting beneficial but limited effects on gut mucosal immunity.

Albumin infusion after reperfusion prevents gut ischemia-reperfusion-induced gut-associated lymphoid tissue atrophy.

BACKGROUND: Our recent study clarified that gut ischemia-reperfusion (I/R) causes gut-associated lymphoid tissue (GALT) mass atrophy, a possible mechanism for increased morbidity of infectious complications after severe surgical insults. Because albumin administration reportedly reduces hemorrhagic shock-induced lung injury, we hypothesized that albumin treatment prevents GALT atrophy due to gut I/R. METHODS: Male mice (n = 37) were randomized to albumin, normal saline, and sham groups. All groups underwent jugular vein catheter insertion. The albumin and normal saline groups underwent 75-minute occlusion of the superior mesenteric artery. During gut ischemia, all mice received normal saline infusions at 1.0 mL/h. The albumin group was given 5% bovine serum albumin in normal saline at 1.0 mL/h for 60 minutes after reperfusion, whereas the normal saline group received 0.9% sodium chloride at 1.0 mL/h. The sham group underwent laparotomy only. Mice were killed on day 1 or 7, and the entire small intestine was harvested. GALT lymphocytes were isolated and counted. Their phenotypes (alphabetaTCR, gammadeltaTCR, CD4, CD8, B220) were determined by flow cytometry. RESULTS: On day 1, the gut I/R groups showed significantly lower total lymphocyte and B cell numbers in Peyer's patches and the lamina propria than the sham group. However, the albumin infusion partially but significantly restored these cell numbers. On day 7, there were no significant differences in any of the parameters measured among the 3 groups. CONCLUSIONS: Albumin infusion after a gut ischemic insult may maintain gut immunity by preventing GALT atrophy.

Influences of long-term antibiotic administration on Peyer's patch lymphocytes and mucosal immunoglobulin A levels in a mouse model.

BACKGROUND: Long-term antibiotic administration is sometimes necessary to control bacterial infections during the perioperative period. However, antibiotic administration may alter gut bacterial flora, possibly impairing gut mucosal immunity. We hypothesized that 1 week of subcutaneous (SC) antibiotic injections would affect Peyer's patch (PP) lymphocyte numbers and phenotypes, as well as mucosal immunoglobulin A (IgA) levels. METHODS: Sixty-one male Institute of Cancer Research mice were randomized to CMZ (cefmetazole 100 mg/kg, administered SC twice a day), IPM (imipenem/cilastatin 50 mg/kg x 2), and control (saline 0.1 mL x 2) groups. After 7 days of treatment, the mice were killed and their small intestines removed. Bacterial numbers in the small intestine were determined using sheep blood agar plates under aerobic conditions (n = 21). PP lymphocytes were isolated to determine cell numbers and phenotypes (CD4, CD8, alphabetaTCR, gammadeltaTCR, B220; n = 40). IgA levels in the small intestinal and bronchoalveolar washings were also measured with ELISA. RESULTS: Antibiotic administration decreased both bacterial number and the PP cell yield compared with the control group. There were no significant differences in either phenotype percentages or IgA levels at any mucosal sites among the 3 groups. CONCLUSIONS: Long-term antibiotic treatment reduces PP cell numbers while decreasing bacterial numbers in the small intestine. It may be important to recognize changes in gut mucosal immunity during long-term antibiotic administration.

Route and type of nutrition influence nuclear factor kappaB activation in peritoneal resident cells.

Morbidity of intra-abdominal abscess is increased when severely injured patients are fed parenterally. Lack of enteral nutrition appears to impair peritoneal cavity host defense. Because the transcription factor nuclear factor kappaB (NFkappaB) regulates various genes involved in inflammatory responses and its activation is important for host defense, we hypothesized that enteral nutrition would preserve appropriate NFkappaB activation in peritoneal resident cells (PRCs), the first defense line against peritoneal contamination. Mice (n = 105) were randomized to chow (n = 38), intravenous (IV)-total parenteral nutrition (TPN) (n = 34), or intragastric (IG)-TPN (n = 33) for 5 days' feeding. In experiment 1, PRCs were harvested for measurement of intranuclear NFkappaB activity with or without in vitro lipopolysaccharide (LPS) stimulation using laser scanning cytometry and enzyme-linked immunoabsorbant assay. PRC numbers tended to be higher in enterally fed mice than in IV-TPN mice. The main PRC subpopulation was macrophages in all groups. NFkappaB activation was increased in response to LPS in chow mice, whereas there was no increase in the IV-TPN group. IG-TPN mice demonstrated moderate NFkappaB activation. In experiment 2, mice underwent cecal ligation and puncture (CLP). Survival was observed up to 5 days. In another set of mice, tumor necrosis factor (TNF) alpha levels of peritoneal lavaged fluid were measured 4 h after CLP. Survival times after CLP improved in the chow and IG-TPN groups compared with the IV-TPN group. TNFalpha levels were significantly higher in the chow than in the IV-TPN group. In conclusion, parenteral nutrition decreases PRC number and blunts NFkappaB activation in PRCs. These changes may impair host defense in the peritoneal cavity.

5-Fluorouracil infusion reduces gut-associated lymphoid tissue cell number and mucosal immunoglobulin A levels.

BACKGROUND: Anticancer drugs have been demonstrated to affect gut mucosal morphology and cause gastrointestinal symptoms. We hypothesized that even small doses of 5-fluorouracil (5-FU) would reduce gut-associated lymphoid tissue (GALT) mass and function. METHODS: Mice underwent IV cannulation and received continuous infusion of normal saline or 10 mg/kg of 5-FU for 5 days. GALT cell numbers, phenotypes, and mucosal immunoglobulin A (IgA) levels were measured. RESULTS: During the infusion, there were no significant differences in food intake or body weight change between the 2 groups. Cell yields from the intraepithelial space and lamina propria of the small intestine were lower in the 5-FU than the control group. The lamina propria CD4/CD8 ratio was reduced in the 5-FU compared with the control group. Intestinal and respiratory tract IgA levels were lower in the 5-FU than in the control group. CONCLUSIONS: A small dose of 5-FU reduces GALT cell number and mucosal IgA levels, regardless of food intake.

Dietary restriction compromises resistance to gut ischemia-reperfusion, despite reduction in circulating leukocyte activation.

BACKGROUND: Gut ischemia-reperfusion (gut I/R) accompanying severe surgical insults leads to neutrophil-mediated injury and is regarded as a triggering event in early multiple-organ failure. Our previous study demonstrated dietary restriction to down-regulate leukocyte activation. Therefore, we hypothesized dietary restriction might be beneficial in terms of surviving I/R. We also evaluated leukocyte activation and the level of organ glutathione, an antioxidative substance. METHODS: Institute of Cancer Research mice received chow, 170 (ad libitum), 119 (MR: mild restriction) or 68 (SR: severe restriction) g/kg per day for 7 days. Exp. 1: The mice (n = 59) underwent 15 or 45 minutes of gut ischemia and survival was observed. Exp. 2: The mice (n = 73) were killed before or 60 or 120 minutes after 15-minute ischemia. Reactive oxygen intermediate (ROI) production by circulating myeloid cells and CD11b expression was determined. Some mice were assessed for nuclear factor kappa B (NFkappaB) activation. Glutathione levels were measured in some of the small intestine and liver samples from each group. RESULTS: Dietary restriction decreased survival. Circulating myeloid cell priming and activation, in terms of ROI production and CD11b expression, were enhanced in the ad libitum group but not in the restricted groups. NFkappaB was activated only in the ad libitum group. Gut and hepatic glutathione levels were lower in the SR than in the ad libitum group. Dietary restriction caused histologic damages in gut, liver, and lung 120 minutes after reperfusion. CONCLUSIONS: Dietary restriction blunts leukocyte priming and activation after gut ischemic insult but worsens the outcome by, at least in part, decreasing antioxidative activities. Clinically, nutrition replenishment may be required to improve the outcome of gut hypoperfusion.

Glutamine infusion during ischemia is detrimental in a murine gut ischemia/reperfusion model.

BACKGROUND: Gut ischemia/reperfusion (I/R) frequently occurs in clinical settings as a result of disproportionate splanchnic hypoperfusion during shock. Glutamine (GLN) supplementation of total parenteral nutrition (TPN) before gut I/R improves survival after gut I/R compared with standard TPN. However, it is unknown whether GLN treatment after the occurrence of the insult is beneficial or not. The aims of this study were to examine effects of GLN infusion during gut ischemia on survival, myeloid cell (neutrophils + monocytes) activation, and vascular permeability in organs. METHODS: Male Institute of Cancer Research (ICR) mice were randomized to control and GLN groups. After IV cannulation, mice underwent 90 (experiments 1 and 2) or 60 (experiment 3) minutes of gut I/R. Control mice received normal saline infusion at 1 mL/h for 60 minutes during ischemia, whereas the GLN group was given 3% GLN solution. In experiment 1, survival rates were monitored for 72 hours (n = 25). In experiment 2, peripheral blood was obtained at 2 or 4 hours after reperfusion (n = 17). Reactive oxygen intermediate (ROI) production by myeloid cells was determined by flow cytometry using dihydrorhodamine 123 with or without phorbol myristate acetate stimulation. Expression of CD11a and CD11b on myeloid cells was also measured. Myeloperoxidase (MPO) activity in the lung was evaluated. In experiment 3, vascular permeability in organs was measured using Evans blue at 2 or 4 hours. RESULTS: In experiment 1, survival time in the GLN group was significantly reduced compared with the control group (p = .02, log-rank test). The survival rates were 92% (12/13) and 42% (5/12) for the control and GLN groups at 12 hours (p = .01) and 38% (5/13) and 0% (0/12) at 48 hours (p = .02), respectively. In experiment 2, ROI production was significantly higher in the GLN group than in the control group after PMA stimulation both at 2 and 4 hours. CD11b expression was significantly higher in the GLN group than in the control group at 4 hours. There was no difference in pulmonary MPO activity at either time point. In experiment 3, GLN infusion significantly increased hepatic vascular permeability compared with saline infusion at 4 hours. CONCLUSIONS: GLN infusion during ischemia is detrimental for survival after gut I/R. A possible mechanism is excessive priming of myeloid cells caused by GLN infusion. Timing of GLN administration is critical for outcome after gut ischemic insult.

Effects of L-arginine infusion during ischemia on gut blood perfusion, oxygen tension, and circulating myeloid cell activation in a murine gut ischemia/reperfusion model.

BACKGROUND: Gut hypoperfusion is considered to be a mechanism for early multiple-organ failure after severe surgical insults. L-Arginine (ARG) may preserve gut microcirculation as a substrate of nitric oxide synthase, but simultaneously may enhance immune cell response. It remains unknown if ARG infusion during gut ischemia improves the outcome after gut ischemia-reperfusion (I/R). METHODS: Male Institute of Cancer Research mice were randomized to control and ARG groups. After i.v. cannulation, mice underwent 90 (Exp. 1) or 60 (Exp. 2 and 3) minutes of gut I/R. Control mice received normal saline infusion at 1 mL/h for 60 minutes during ischemia, whereas the ARG group was given 1% ARG hydrochloride solution. In Exp. 1, survival was observed for 72 hours (n = 35). In Exp. 2, blood perfusion and oxygen tension of the small intestine were measured (n = 9). In Exp. 3, peripheral blood was obtained at 2 or 4 hours after reperfusion (n = 22). Reactive oxygen intermediate (ROI) production by myeloid cells with or without phorbol myristate acetate (PMA) stimulation and expression of CD11a and CD11b on myeloid cells were examined using flow cytometry. RESULTS: Exp. 1: There was no significant difference in survival times (log rank test, p = .2). However, survival rates at 12 hours were 72% (13/18) for the control group and 35% (6/17) for the ARG group (p < .05 Fisher). Exp. 2: ARG infusion significantly improved gut blood perfusion ratio during ischemia but had no effect on oxygen tension. Exp. 3: In the ARG group, ROI production with PMA and CD11b expression at 4 hours were higher than those at 2 hours, whereas there were no significant changes in the control mice. CONCLUSIONS: ARG infusion improves intestinal blood perfusion during ischemia but primes and activates circulating myeloid cells excessively. Consequently, i.v. infusion of ARG during ischemia reduces survival rate.

L-arginine-enriched parenteral nutrition affects lymphocyte phenotypes of gut-associated lymphoid tissue.

BACKGROUND: Experimentally, total parenteral nutrition (TPN) diminishes gut-associated lymphoid tissue (GALT) cell numbers and function. Although glutamine supplementation is known to reverse TPN-induced changes in GALT, effects of another conditionally essential amino acid, L-arginine (ARG), on GALT remain unclear. METHODS: Twenty-two male Institute of Cancer Research mice were randomized to standard TPN (0.3% arginine, STD-total parenteral nutrition) or 1% ARG-enriched TPN (ARG-total parenteral nutrition). After 5 days of feeding, lymphocytes were harvested from Peyer's patches (PP), the lamina propria, and intraepithelial (IE) spaces of the small intestine to determine cell yields. Lymphocyte phenotypes (alphabetaTCR, gammadeltaTCR, CD4, CD8, and B220 as a B cell marker) were determined using flow cytometry. IgA levels in washings of the small intestine, upper respiratory tract, and lungs were measured with ELISA. RESULTS: ARG-total parenteral nutrition did not affect lymphocyte yields. The percentages of CD4+ cells in PP and IE, and alphabetaTCR+ cells in PP, were significantly higher in the ARG-total parenteral nutrition than in the STD-total parenteral nutrition mice, without marked differences in other phenotypes examined. There were no significant differences in intestinal and respiratory tract IgA levels between the 2 groups of mice. CONCLUSIONS: One percent ARG supplementation of TPN does not improve GALT cell number or mucosal IgA level but benefits to increase CD4+ cell percentages in GALT.

Surgical resection of a solitary para-aortic lymph node metastasis from hepatocellular carcinoma.

Lymph node (LN) metastases from hepatocellular carcinoma (HCC) are considered uncommon. We describe the surgical resection of a solitary para-aortic LN metastasis from HCC. A 65-year-old Japanese man with B-type liver cirrhosis was admitted for the evaluation of a liver tumor. He had already undergone radiofrequency ablation, transcatheter arterial chemoembolization, and percutaneous ethanol injection therapy for HCC. Despite treatment, viable regions remained in segments 4 and 8. We performed a right paramedian sectionectomy with partial resection of the left paramedian section of the liver. Six months later, serum concentrations of alpha-fetoprotein (189 ng/mL) and PIVKA-2 (507 mAU/mL) increased. Enhanced computed tomography of the abdomen revealed a tumor (20 mm in diameter) on the right side of the abdominal aorta. Fluorine-18 fluorodeoxyglucose positron emission tomography revealed an increased standard uptake value. There was no evidence of recurrence in other regions. Esophagogastroduodenoscopy and colonoscopy revealed no malignant tumor in the gastrointestinal tract. Para-aortic LN metastasis from HCC was thus diagnosed. We performed lymphadenectomy. Histopathological examination revealed that the tumor was largely necrotic, with poorly differentiated HCC on its surface, which confirmed the suspected diagnosis. After 6 mo tumor marker levels were normal, with no evidence of recurrence. Our experience suggests that a solitary para-aortic LN metastasis from HCC can be treated surgically.

Augmented bacterial elimination by Kupffer cells after IL-18 pretreatment via IFN-γ produced from NK cells in burn-injured mice.

We recently demonstrated that IL-18 injections following burn restored IFN-γ production and increased mouse survival after bacterial infection. However, it has yet to be fully elucidated how the IL-18 therapy affects the function of phagocytic cells. We investigated the effect of IL-18 therapy on function and interaction of Kupffer cells and NK cells in burned mice. C57BL/6 mice received a 20% full-thickness burn, followed by multiple injections with IL-18. Although burn-injured mice had decreased expression of IL-18 receptors on the NK/NKT cells 5 days after injury, multiple IL-18 injections restored this expression. IL-18 treatment also augmented Kupffer cell phagocytosis. Although burn decreased the number of CD68(+) Kupffer cells with phagocytic activity, IL-18 treatment partially restored their proportion, and augmented phagocytosis-induced ROS production in CD68(+) Kupffer cells after the injection of heat-killed Escherichia coli. Consistently, IL-18 restored the impaired E. coli killing activity of Kupffer cells of burn-injured mice. Such Kupffer cell activation by IL-18 was abrogated by the deletion of NK cells or IFN-γ. In conclusion, IL-18 therapy in burn-injured mice enhanced function of CD68(+) Kupffer cells via the activation of liver NK cells and augmentation of their IFN-γ production, thereby improving survival after E. coli infection.

Gut ischemia-reperfusion affects gut mucosal immunity: a possible mechanism for infectious complications after severe surgical insults.

OBJECTIVE: To examine influences of gut ischemia/reperfusion (I/R) on gut-associated lymphoid tissue (GALT) mass and function. DESIGN: Prospective, randomized controlled study. SETTING: Research laboratory. SUBJECTS: Male Institute of Cancer Research mice. INTERVENTIONS: Ninety mice were randomized to three groups: I/R (60-min gut ischemia), sham (laparotomy only), and control (no operation). On days 1, 2, 4, 7, and 10, mice were killed to harvest lymphocytes from Peyer patches, the intraepithelial space, and the lamina propria (LP) of the small intestine. Respiratory tract and small intestinal washings were also obtained. MEASUREMENTS AND MAIN RESULTS: Gut I/R significantly reduced lymphocyte numbers in Peyer patches, the intraepithelial space, and the LP. The reduction was prominent in GALT effector sites, that is, the intraepithelial space and LP, but numbers recovered quickly in LP. Changes in cell numbers in Peyer patches, GALT inductive sites, were subtle but persistent. Gut I/R reduced B cell numbers in Peyer patches; alphabeta T cell receptor (TCR)+, gammadeltaTCR+, CD8+, and B cell numbers in the intraepithelial space; and gammadeltaTCR+, CD8+, and B cell numbers in the LP, in comparison with the sham or control group. There were no significant differences in respiratory tract immunoglobulin A levels between the I/R and sham groups. Intestinal immunoglobulin A was elevated on day 1 in the I/R group, with no significant difference after day 2 in comparison with the sham group. CONCLUSIONS: Despite the maintained mucosal immunoglobulin A level, gut I/R markedly reduces GALT cell numbers, with changes in lymphocyte phenotypes. These alterations may be associated with increased morbidity due to infectious complications after severe surgical insults.

The development of memory trace depending on the number of the standard stimuli.

The mismatch negativity (MMN) component of the event-related potentials reflects the automatic detection mechanism of sound change. MMN is elicited by a neuronal mismatch process between deviant (infrequent) auditory input and the sensory memory trace of the standard (frequent) stimuli. Although many previous studies have investigated MMN to reveal the sensory memory mechanism, the development of memory representation still remains unclear, in particular, the topographical aspect of the trace-development in sensory memory has not been clarified. We measured the frontal and the temporal MMN components, respectively, when the sound trace was developed as the number of standard stimuli was changed to 1, 3, 5 or 7. In this experiment, the inter-train interval was 15 sec. The stimulus train with the different frequency of 800 Hz, 900 Hz, or 1000 Hz was repeatedly presented. Thus, we reduced the influence of the previous train. For the first time, we found not only the enhanced amplitude but also the shortened latency for both MMN components when the number of standard stimuli was increased. These findings indicate that both frontal and temporal MMN components reflect the development of memory trace depending on the number of standard stimuli.