Exosome-mediated delivery of super-repressor IκBα alleviates inflammation and joint damages in rheumatoid arthritis

BACKGROUND

This study aims to investigate the potential anti-inflammatory effects of exosomes engineered to carry super-repressor IκB (Exo-srIκB), an exosome-based NF-κB inhibitor, in the context of RA.

METHODS

Peripheral blood mononuclear cells (PBMCs) and synovial fluid mononuclear cells (SFMCs) were collected from patients diagnosed with RA and treated with Exo-srIκB to test the therapeutic potential. Flow cytometry analysis was performed to assess the production of inflammatory cytokines (IL-17A and GM-CSF) by the cells. ELISA was utilized to measure the levels of TNF-α, IL-17A, IL-6, and GM-CSF. Arthritis was induced in SKG mice by intraperitoneal injection of curdlan. DBA/1 J mice were used in collagen-induced arthritis (CIA) experiments. After the development of arthritis, mice were injected with either Exo-Naïve (control exosome) or Exo-srIκB. Arthritis scores were recorded biweekly, and histological observations of the ankle joint were conducted using H&E and safranin-O staining. Additionally, bone erosion was evaluated using micro-CT imaging.

RESULTS

In the ex vivo study involving human PBMCs and SFMCs, treatment with Exo-srIκB demonstrated a notable reduction in inflammatory cytokines. Furthermore, in both the SKG and CIA models, Exo-srIκB treatment exhibited significant reductions in inflammation, cartilage destruction, and bone erosion within the joint tissues when compared to the Exo-Naive control group. Additionally, the radiographic score assessed through microCT showed a significant decrease compared to the Exo-Naive control group.

CONCLUSION

Overall, these findings suggest that Exo-srIκB possesses anti-inflammatory properties in human RA cells and animal models, making it a promising therapeutic candidate for the treatment of RA.

Exosome-Based Delivery of Super-Repressor IκBα Alleviates Alcohol-Associated Liver Injury in Mice

Activation of Kupffer cells (KCs) by gut-derived lipopolysaccharide (LPS) instigates nuclear factor-κB (NF-κB)-mediated inflammatory responses in alcohol-associated liver diseases (ALD). Here, we utilized a novel optogenetically engineered exosome technology called 'exosomes for protein loading via optically reversible protein-protein interactions (EXPLOR)' to efficiently deliver the super-repressor IκB-loaded exosomes (Exo-srIκB) to the liver and examined its therapeutic potential in acute-on-chronic alcohol-associated liver injury. We detected enhanced uptake of DiI-labeled Exo-srIκB by LPS-treated inflammatory KCs, which suppressed LPS-induced inflammatory gene expression levels. In animal experiments, a single intravenous injection of Exo-srIκB prior to alcohol binge drinking significantly attenuated alcohol-associated hepatic steatosis and infiltration of neutrophils and macrophages but not a liver injury. Notably, three consecutive days of Exo-srIκB injection remarkably reduced alcohol-associated liver injury, steatosis, apoptosis of hepatocytes, fibrosis-related gene expression levels in hepatic stellate cells, infiltration of neutrophils and macrophages, and inflammatory gene expression levels in hepatocytes and KCs. In particular, the above effects occurred with inhibition of nuclear translocation of NF-κB in liver tissues, and these beneficial effects of Exo-srIκB on ALD were shown regardless of doses. Our results suggest an exosome-based modulation of NF-κB activity in KCs by Exo-srIκB as a novel and efficient therapeutic approach in ALD.

Biodistribution of Exosomes and Engineering Strategies for Targeted Delivery of Therapeutic Exosomes

Exosomes are cell-secreted nano-sized vesicles which deliver diverse biological molecules for intercellular communication. Due to their therapeutic potential, exosomes have been engineered in numerous ways for efficient delivery of active pharmaceutical ingredients to various target organs, tissues, and cells. In vivo administered exosomes are normally delivered to the liver, spleen, kidney, lung, and gastrointestinal tract and show rapid clearance from the blood circulation after systemic injection. The biodistribution and pharmacokinetics (PK) of exosomes can be modulated by engineering various factors such as cellular origin and membrane protein composition of exosomes. Recent advances accentuate the potential of targeted delivery of engineered exosomes even to the most challenging organs including the central nervous system. Major breakthroughs have been made related to various imaging techniques for monitoring in vivo biodistribution and PK of exosomes, as well as exosomal surface engineering technologies for inducing targetability. For inducing targeted delivery, therapeutic exosomes can be engineered to express various targeting moieties via direct modification methods such as chemically modifying exosomal surfaces with covalent/non-covalent bonds, or via indirect modification methods by genetically engineering exosome-producing cells. In this review, we describe the current knowledge of biodistribution and PK of exosomes, factors determining the targetability and organotropism of exosomes, and imaging technologies to monitor in vivo administered exosomes. In addition, we highlight recent advances in strategies for inducing targeted delivery of exosomes to specific organs and cells.

Exosome-based delivery of super-repressor IκBα ameliorates kidney ischemia-reperfusion injury

Ischemia-reperfusion injury is a major cause of acute kidney injury. Recent studies on the pathophysiology of ischemia-reperfusion-induced acute kidney injury showed that immunologic responses significantly affect kidney ischemia-reperfusion injury and repair. Nuclear factor (NF)-ĸB signaling, which controls cytokine production and cell survival, is significantly involved in ischemia-reperfusion-induced acute kidney injury, and its inhibition can ameliorate ischemic acute kidney injury. Using EXPLOR, a novel, optogenetically engineered exosome technology, we successfully delivered the exosomal super-repressor inhibitor of NF-ĸB (Exo-srIĸB) into B6 wild type mice before/after kidney ischemia-reperfusion surgery, and compared outcomes with those of a control exosome (Exo-Naïve)-injected group. Exo-srIĸB treatment resulted in lower levels of serum blood urea nitrogen, creatinine, and neutrophil gelatinase-associated lipocalin in post-ischemic mice than in the Exo-Naïve treatment group. Systemic delivery of Exo-srIĸB decreased NF-ĸB activity in post-ischemic kidneys and reduced apoptosis. Post-ischemic kidneys showed decreased gene expression of pro-inflammatory cytokines and adhesion molecules with Exo-srIĸB treatment as compared with the control. Intravital imaging confirmed the uptake of exosomes in neutrophils and macrophages. Exo-srIĸB treatment also significantly affected post-ischemic kidney immune cell populations, lowering neutrophil, monocyte/macrophage, and T cell frequencies than those in the control. Thus, modulation of NF-ĸB signaling through exosomal delivery can be used as a novel therapeutic method for ischemia-reperfusion-induced acute kidney injury.

Exosomal delivery of NF-κB inhibitor delays LPS-induced preterm birth and modulates fetal immune cell profile in mouse models

Accumulation of immune cells and activation of the pro-inflammatory transcription factor NF-κB in feto-maternal uterine tissues is a key feature of preterm birth (PTB) pathophysiology. Reduction of the fetal inflammatory response and NF-κB activation are key strategies to minimize infection-associated PTB. Therefore, we engineered extracellular vesicles (exosomes) to contain an NF-κB inhibitor, termed super-repressor (SR) IκBα. Treatment with SR exosomes (1 × 1010 per intraperitoneal injection) after lipopolysaccharide (LPS) challenge on gestation day 15 (E15) prolonged gestation by over 24 hours (PTB ≤ E18.5) and reduced maternal inflammation (n ≥ 4). Furthermore, using a transgenic model in which fetal tissues express the red fluorescent protein tdTomato while maternal tissues do not, we report that LPS-induced PTB in mice is associated with influx of fetal innate immune cells, not maternal, into feto-maternal uterine tissues. SR packaged in exosomes provides a stable and specific intervention for reducing the inflammatory response associated with PTB.

Landscape of Infiltrating T Cells in Liver Cancer Revealed by Single-Cell Sequencing

Systematic interrogation of tumor-infiltrating lymphocytes is key to the development of immunotherapies and the prediction of their clinical responses in cancers. Here, we perform deep single-cell RNA sequencing on 5,063 single T cells isolated from peripheral blood, tumor, and adjacent normal tissues from six hepatocellular carcinoma patients. The transcriptional profiles of these individual cells, coupled with assembled T cell receptor (TCR) sequences, enable us to identify 11 T cell subsets based on their molecular and functional properties and delineate their developmental trajectory. Specific subsets such as exhausted CD8⁺ T cells and Tregs are preferentially enriched and potentially clonally expanded in hepatocellular carcinoma (HCC), and we identified signature genes for each subset. One of the genes, layilin, is upregulated on activated CD8⁺ T cells and Tregs and represses the CD8⁺ T cell functions in vitro. This compendium of transcriptome data provides valuable insights and a rich resource for understanding the immune landscape in cancers.

Inhibitory Effect of Imiquimod-Induced Psoriasis-Like Skin Inflammation in Mice by Histamine H4 Receptor Agonist 4-Methylhistamine

Psoriasis is a chronic inflammatory immune-mediated autoimmune skin disorder. The histamine H4 receptor (H4R) agonist 4-methylhistamine (4-MH) plays an important role in immunomodulation of inflammatory responses associated with allergic inflammatory diseases. In this study, we investigated the effects of H4R agonist 4-MH on the development of imiquimod (IMQ)-induced psoriasis-like skin inflammation in mice and explored the immunoregulatory mechanism involved. The total clinical severity scores were significantly ameliorated by treatment with 4-MH (20 mg/kg) and 4-MH (40 mg/kg). Histological analysis of the skin revealed that 4-MH (20 mg/kg) and 4-MH (40 mg/kg) significantly attenuated the psoriatic phenotypes, including epidermal hyperplasis, hyperkeratosis and lymphocytes infiltration. Treatment with 4-MH (20 mg/kg) and 4-MH (40 mg/kg) led to reductions in the levels of Th1 cytokines (TNF-α, IFN-α, and IL-27) in the serum and dorsal skin, whereas Th17 cytokines levels (IL-17A and IL-23) did not change in response to treatment with 4-MH (20 mg/kg) and 4-MH (40 mg/kg). Furthermore, the number of CD4(+) CD25(+) FoxP3(+) regulatory T (Treg) cells was significantly increased by treatment with 4-MH (40 mg/kg). Taken together, these results imply that H4R agonist 4-MH might be an effective immunomodulatory approach for treatment of patients with psoriasis and the effects may be related to inhibited epidermal alteration, selectively reduced Th1 pro-inflammatory cytokines, and recruited CD4(+) CD25(+) FoxP3(+) Treg cells.

The novel miR-9500 regulates the proliferation and migration of human lung cancer cells by targeting Akt1

MicroRNAs have crucial roles in lung cancer cell development. They regulate cell growth, proliferation and migration by mediating the expression of tumor suppressor genes and oncogenes. We identified and characterized the novel miR-9500 in human lung cancer cells. The miR-9500 forms a stem-loop structure and is conserved in other mammals. The expression levels of miR-9500 were reduced in lung cancer cells and lung cancer tissues compared with normal tissues, as verified by TaqMan miRNA assays. It was confirmed that the putative target gene, Akt1, was directly suppressed by miR-9500, as demonstrated by a luciferase reporter assay. The miR-9500 significantly repressed the protein expression levels of Akt1, as demonstrated via western blot, but did not affect the corresponding mRNA levels. Akt1 has an important role in lung carcinogenesis, and depletion of Akt1 has been shown to have antiproliferative and anti-migratory effects in previous studies. In the current study, the overexpression of miR-9500 inhibited cell proliferation and the expression of cell cycle-related proteins. Likewise, the overexpression of miR-9500 impeded cell migration in human lung cancer cells. In an in vivo assay, miR-9500 significantly suppressed Fluc expression compared with NC and ASO-miR-9500, suggesting that cell proliferation was inhibited in nude mice. Likewise, miR-9500 repressed tumorigenesis and metastasis by targeting Akt1. These data indicate that miR-9500 might be applicable for lung cancer therapy.

Validity and reliability of aortic pulse wave velocity and augmentation index determined by the new cuff-based SphygmoCor Xcel

Aortic pulse wave velocity (AoPWV) and augmentation index (AIx) are commonly used measures of large elastic artery stiffness and wave reflection, respectively. Recently, a new cuff-based SphygmoCor device (Xcel) has been developed to measure both AoPWV and AIx. We sought to examine the following: (1) the validity of Xcel compared with the well-validated tonometry-based SphygmoCor device (MM3); (2) the intratest and day-to-day reliability of Xcel; (3) the influence of body side (right or left) on Xcel measurements; and (4) the relation of Xcel measurements to carotid artery compliance, distensibility and β-stiffness index. We found that measurements of AoPWV and AIx between Xcel and MM3 were not different (P=0.26 and P=0.43, N=22 and 26, respectively) and were strongly related (r=0.85 and 0.75, P<0.0001), and based on Bland-Altman plots there was good agreement between them. Intra-test (intraclass correlation=0.996 and 0.983, P<0.0001; AoPWV and AIx, N=24 and 26, respectively) and day-to-day reliability (intraclass correlation=0.979 and 0.939, P<0.0001) were high. Xcel AoPWV and AIx on the left versus right body side were not different (P=0.19 and P=0.58, N=14 and 15, respectively) and were highly correlated (r=0.99 and 0.94, P<0.0001). AoPWV and AIx measured with Xcel were positively related with β-stiffness index (r=0.62 and 0.51, P< or = 0.005, N=23 and 24, respectively) and negatively related with distensibility (r = -0.58 and -0.44, P < or = 0.02, N=23 and 24, respectively). In conclusion, Xcel measures of AIx and AoPWV are valid, highly reliable and not affected by body side. Xcel is a useful tool for use in research and the clinic.

Viral infection of the lung: host response and sequelae

Because of its essential role in gas exchange and oxygen delivery, the lung has evolved a variety of strategies to control inflammation and maintain homeostasis. Invasion of the lung by pathogens (and in some instances exposure to certain noninfectious particulates) disrupts this equilibrium and triggers a cascade of events aimed at preventing or limiting colonization (and more importantly infection) by pathogenic microorganisms. In this review we focus on viral infection of the lung and summarize recent advances in our understanding of the triggering of innate and adaptive immune responses to viral respiratory tract infection, mechanisms of viral clearance, and the well-recognized consequences of acute viral infection complicating underlying lung diseases, such as asthma.

A novel mechanism regulating anti-viral humoral response: interplay between IL-21, LAPC and TFH in anti-IAV humoral response. (P6174)

The humoral immune response to most respiratory virus infections plays a prominent role in virus clearance and is essential for resistance to reinfection. T follicular helper (TFH) cells are believed to support the development both of a potent primary antibody response and of the germinal center response critical for memory B cell development. Using a model of primary murine influenza A virus (IAV) infection, we demonstrate that a novel APC, the LAPC (Late-activator APC), promotes the TFH response in the draining LNs (dLNs) of the IAV-infected lungs. LAPCs migrate from the infected lungs to the dLN “late,” i.e., 6 d after infection, which is concomitant with TFH differentiation. LAPC migration is CXCR3-CXCL9-dependent, and LAPC triggering of TFH cell development requires ICOS-ICOSL-dependent signaling. In IAV infection, the host immune system control this LAPC-mediated TFH differentiation via IL-21.We have demonstrated that IL-21, a well known TFH differentiation inducing factor, produced by NK T-cells in the dLN acts on lymph node resident T cells to stimulate TNF-α release by the T-cells. TNF-α in turn stimulates dLN resident dendritic cells to secrete CXCL9, a potent chemotactic stimulus for migration of CXCR3 expressing lung resident LAPC into the dLN. It is then the migrant LAPC which acts to modulate TFH differentiation during respiratory viral infection. Our results reveal a novel and previously unsuspected mechanism for regulating anti-viral TFH and humoral responses.

LAPCs promote follicular helper T cell differentiation of Ag-primed CD4+ T cells during respiratory virus infection

Late activator antigen-presenting cells promote Tfh differentiation of antigen-primed CD4⁺ T cells and antibody responses in influenza A virus infection.

The humoral immune response to most respiratory virus infections plays a prominent role in virus clearance and is essential for resistance to reinfection. T follicular helper (Tfh) cells are believed to support the development both of a potent primary antibody response and of the germinal center response critical for memory B cell development. Using a model of primary murine influenza A virus (IAV) infection, we demonstrate that a novel late activator antigen-presenting cell (LAPC) promotes the Tfh response in the draining lymph nodes (dLNs) of the IAV-infected lungs. LAPCs migrate from the infected lungs to the dLN “late,” i.e., 6 d after infection, which is concomitant with Tfh differentiation. LAPC migration is CXCR3-dependent, and LAPC triggering of Tfh cell development requires ICOS–ICOSL–dependent signaling. LAPCs appear to play a pivotal role in driving Tfh differentiation of Ag-primed CD4⁺ T cells and antiviral antibody responses.

Childhood obesity in ambulatory children and adolescents with spastic cerebral palsy in Korea

OBJECTIVE

Childhood obesity is an emerging health issue in Korea. We investigated the prevalence of obesity and its trend over time in ambulatory Korean children with CP.

METHODS

We retrospectively reviewed the medical records of 1,397 children with CP between 1995 and 2008. The data were grouped into 4 time periods (1995-1997, 1998-2002, 2003-2004 and 2005-2008). The prevalence of obesity over each period and its relationship to gender, birth weight, age, and gross motor function classification system were investigated.

RESULTS

The percentage of obese children was 5.8%, overweight children 11.2%, and underweight children 10.4%. The prevalence of obesity significantly increased from the first time period to the third time period. The prevalence of obesity found in our study was significantly lower than the report from the U.S.A. during same time period between 1994 and 2004 (p<0.05). The prevalence of obesity significantly decreased with age as well.

CONCLUSIONS

The prevalence of obesity in our subjects significantly increased and has reached a plateau in recent years. Compared to the prevalence of childhood obesity in ambulatory individuals with CP in the U.S.A. study, the prevalence in our study was significantly lower.

Identification of a novel antigen-presenting cell population modulating antiinfluenza type 2 immunity

Antiinfluenza type 2 (T2) immunity contributes to both immunopathology and immunoprotection, yet the underlying mechanisms modulating T2 immunity remain ill defined. We describe a novel mouse antigen (Ag)-presenting cell (APC), designated late-activator APC (LAPC). After pulmonary influenza A (H1N1) virus infection, LAPCs enter the lungs, capture viral Ag, and subsequently migrate to the draining lymph node (DLN) and spleen, with delayed kinetics relative to dendritic cells (DCs). In the DLN, influenza virus–activated LAPCs present Ag and selectively induce T helper type 2 (Th2) effector cell polarization by cell–cell contact–mediated modulation of GATA-3 expression. In adoptive transfer experiments, influenza virus–activated LAPCs augmented Th2 effector T cell responses in the DLN, increased production of circulating antiinfluenza immunoglobulin, and increased levels of T2 cytokines in bronchoalveolar lavage fluid in recipient influenza virus–infected mice. LAPC-recipient mice exhibited exacerbated pulmonary pathology, with delayed viral clearance and enhanced pulmonary eosinophilia. Collectively, our results identify and highlight the importance of LAPCs as immunomodulators of T2 immunity during influenza A virus infection.

The short-term effects of combined modified constraint-induced movement therapy and botulinum toxin injection for children with spastic hemiplegic cerebral palsy

OBJECTIVE

The aim of this study was to investigate whether modified constraint-induced movement therapy (mCIMT) following a botulinum type A toxin (BoNT-A) injection enhances the effects of the BoNT-A injection into the spastic upper limb of children with hemiplegic cerebral palsy (CP).

METHODS

A combined therapy with mCIMT and BoNT-A was given to 17 children in group A. Fifteen children in group B received only the BoNT-A injection. The muscle tone, the movement pattern, and the How Often and the How Well scales in the revised Pediatric Motor Activity Log (revised PMAL) were assessed before and 3 weeks after intervention.

RESULTS

Three participants in group A dropped out due to poor tolerance of mCIMT. There were significant improvements in the muscle tone and the movement patterns for both groups (p<0.05), and the changes were not significantly different between the two groups. The How Often and the How Well scales in the revised PMAL were significantly improved in group A (p<0.05), but not in group B.

CONCLUSION

A combined therapy of mCIMT and BoNT-A seems to be helpful to enhance the effects of the BoNT-A injection in the functional use of the affected limb in children with hemiplegic CP.

Identification of a novel antigen presenting cell population modulating anti-influenza type-2 immunity (131.3)

Anti-influenza type 2 (T2) immunity contributes to both immunoprotection and immunopathology, yet the underlying mechanisms modulating T2 immunity remain ill-defined. Here, we describe a novel murine antigen (Ag) presenting cell (APC) population, designated virus activated plasmacytoid (VAP) cells: mPDCA1+CD11c-TcR-β-B220-CD19-CD38+CD44intCD45+Gr1+. VAP cells are bone marrow derived leukocytes. Phenotypic, morphologic and molecular characterization distinguished VAP cells from other immune cell populations. Pulmonary influenza A virus infection activates circulating VAP cells to enter the lungs and produce interleukin (IL)-25, a strong inducer of T2 pulmonary inflammation. Subsequently, VAP cells capture viral Ag in the lungs and migrate to the draining lymph node (DLN) and spleen, with delayed kinetics relative to DCs, where they show APC activity. In the DLN, influenza virus activated VAP cells produce IL-4 and induce T helper (TH) 2 effector cell polarization by modulating GATA-3 expression. Finally, adoptive transfer of influenza virus activated VAP cells enhanced TH2 effector T cell responses in influenza virus infected recipient mice and subsequently, anti-influenza T2 humoral responses including IgG1 and G2b were significantly increased. Collectively, our results highlight the importance of VAP cells as novel immuno-modulators of T2 immunity against influenza A virus infection in mouse.

These studies were supported by a Canadian Institutes of Health Research grant MOP-15094 to E.N.F.

J.K.Y. was supported by a Connaught Scholarship and an Ontario Graduate Scholarship in Science and Technology.

Effect of food on the pharmacokinetics of YH439 and its metabolites in rats

The pharmacokinetics of YH439 and its metabolites were investigated after oral administration of YH439 to rats to investigate the food effect. After oral administration of YH439, its metabolites, M4 and M5 were detected in plasma. YH439 was not detected in the plasma for both fasted and fed rats for all doses studied. The pharmacokinetic parameters of the metabolites were not affected by food at all doses studied. The results of this study indicated that there are no significant food effects on the pharmacokinetics of YH439 and its metabolites in rats.

Human chorionic gonadotropin is an immune modulator and can prevent autoimmune diabetes in NOD mice

AIMS/HYPOTHESIS

Expression of T helper (Th)1 cytokine mRNA in pregnant women is known to be inversely correlated with serum human chorionic gonadotropin (hCG). Type 1 diabetes is a Th1-mediated autoimmune disease, in which intervention at an early stage of the autoimmune process can prevent disease progression. We hypothesised that immune modulation by treating young NOD mice with hCG may prevent diabetes.

METHODS

Female NOD mice were treated with hCG or recombinant hCG from 3 to 15 weeks of age and the incidence of diabetes and development of insulitis was determined. CD4(+) and CD8(+) T cell populations, T cell proliferation, cytokine production and CD4(+)CD25(+) regulatory T cells were examined and adoptive transfer experiments were performed.

RESULTS

Both purified and recombinant hCG prevented development of diabetes in NOD mice. hCG decreased the proportion and number of CD4(+) and CD8(+) T cells and inhibited T cell proliferative responses against beta cell antigens. hCG treatment suppressed IFN-gamma production, but increased IL-10 and TGF-beta production in splenocytes stimulated with anti-CD3 antibody. hCG treatment also suppressed TNF-alpha production in splenocytes stimulated with lipopolysaccharide. Furthermore, hCG treatment increased the CD4(+)CD25(+)/CD4(+) T cell ratio in spleen and pancreatic lymph nodes. Depletion of CD4(+)CD25(+) T cells from splenocytes of hCG-treated NOD mice abolished their preventive effect on diabetes transfer.

CONCLUSIONS/INTERPRETATION

We conclude that hCG has an immunomodulatory effect by downregulating effector cells, including Th1 cells, CD8(+) T cells and macrophages, and increasing the CD4(+)CD25(+)/CD4(+) T cell ratio, thus preventing autoimmune diabetes in NOD mice.

False susceptibility to cefotetan reported by MicroScan for DHA-type AmpC beta-lactamase-producing Klebsiella pneumoniae

This study evaluated the accuracy of cefotetan susceptibility determination using the MicroScan WalkAway system for AmpC-producing Klebsiella pneumoniae. In total, 57 K. pneumoniae isolates that showed a D-shape flattening in a double-disk synergy test were studied. Cefotetan MICs were determined by the agar dilution method. The bla(DHA) gene was detected in all 57 isolates, one of which co-harboured bla(CMY-1). According to the MicroScan system, 28 isolates were susceptible, 18 were intermediately-resistant, and 11 were resistant to cefotetan. Compared with the agar dilution method, very major, minor and major error rates were 28.1% (16/57), 47.4% (27/57) and 1.8% (1/57), respectively.

p53 deficiency and defective mitotic checkpoint in proliferating T lymphocytes increase chromosomal instability through aberrant exit from mitotic arrest

During the proliferation of T cells for successful immune responses against pathogens, the fine regulation of cell cycle is important to the maintenance of T cell homeostasis and the prevention of lymphoproliferative disorders. However, it remains to be elucidated how the cell cycle is controlled at the mitotic phase in proliferating T cells. Here, we show that during the proliferation of primary T cells, the disruption of the mitotic spindle leads to cell-cycle arrest at mitosis and that prolonged mitotic arrest results in not only apoptosis but also the form of chromosomal instability observed in human cancers. It is interesting that in response to spindle damage, the phosphorylation of BubR1, a mitotic checkpoint kinase, was significantly induced in proliferating T cells, and the expression of the dominant-negative mutant of BubR1 compromised mitotic arrest and subsequent apoptosis and thus led to the augmentation of polyploidy formation. We also show that in response to prolonged spindle damage, the expression of p53 but not of p73 was significantly induced. In addition, following sustained mitotic arrest, p53-deficient T cells were found to be more susceptible to polyploidy formation than the wild type. These results suggest that during flourishing immune response, mitotic checkpoint and p53 play important roles in the prevention of chromosomal instability and in the maintenance of the genomic integrity of proliferating T cells.

Toxicity of the herbicide glufosinate-ammonium to predatory insects and mites of Tetranychus urticae (Acari: Tetranychidae) under laboratory conditions

The toxicities of the herbicide glufosinate-ammonium to three predatory insect and two predatory mite species of Tetranychus urticae Koch were determined in the laboratory by the direct contact application. At a concentration of 540 ppm (a field application rate for weed control in apple orchards), glufosinate-ammonium was almost nontoxic to eggs of Amblyseius womersleyi Schicha, Phytoseiulus persimilis Athias-Henriot, and T. urticae but highly toxic to nymphs and adults of these three mite species, indicating that a common mode of action between predatory and phytophagous mites might be involved. In tests with predatory insects using 540 ppm, glufosinate-ammonium revealed little or no harm to larvae and pupae of Chrysopa pallens Rambur but was slightly harmful to eggs (71.2% mortality), nymphs (65.0% mortality), and adults (57.7% mortality) of Orius strigicollis Poppius. The herbicide showed no direct effect on eggs and adults of Harmonia axyridis (Pallas) but was harmful, slightly harmful, and harmless to first instars (100% mortality), fourth instars (51.1% mortality), and pupae (24.5% mortality), respectively. The larvae and nymphs of predators died within 12 h after treatment, suggesting that the larvicidal and nymphicidal action may be attributable to a direct effect rather than an inhibitory action of chitin synthesis. On the basis of our data, glufosinate-ammonium caused smaller effects on test predators than on T. urticae with the exception of P. persimilis, although the mechanism or cause of selectivity remains unknown. Glufosinate-ammonium merits further study as a key component of integrated pest management.

Pharmacokinetics of a new reversible proton pump inhibitor, YH1885, after intravenous and oral administrations to rats and dogs: hepatic first-pass effect in rats

The pharmacokinetics of YH1885 were evaluated after intravenous (iv) and oral administrations of the drug to rats and dogs. The reason for the low extent of bioavailability (F) of YH1885 after oral administration of the drug to rats and the absorption of the drug from various rat gastrointestinal (GI) segments were also investigated. After iv administration of YH1885, 5-20 mg kg(-1), to rats, the pharmacokinetic parameters of YH1885 seem to be independent of the drug at the dose ranges studied. After oral administration of YH1885, 50-200 mg kg(-1), to rats, the area under the plasma concentration-time curve from time zero to 12 or 24 h (AUC(0-12 h) or AUC(0-24 h)) was proportional to the oral dose of the drug, 50-100 mg kg(-1), however, the AUC(0-24 h) value at 200 mg kg(-1) increased with less proportion to the dose increase (324, 689, and 815 microg x min mL(-1) for 50, 100, and 200 mg kg(-1), respectively) due to the poor water solubility of the drug. This was proved by the considerable increase in the percentages of the oral dose remaining in the entire GI tract as unchanged YH1885 at 24 h (11.8, 15.3, and 42.8% for 50, 100, and 200 mg kg(-1), respectively). The F value after oral administration of YH1885 to rats was relatively low; the value was approximately 40% at the oral dose of 50 and 100 mg kg(-1). The reason for the low F in rats was investigated. The liver showed the highest metabolic activity for YH1885 based on an in vitro rat tissue homogenate study; hence, the liver first-pass effect was estimated. The value of AUC after intraportal administration of the drug, 5 mg kg(-1), was approximately 70% (116 versus 163 microg x min mL(-1)) of that after iv administration of the drug, 5 mg kg(-1), to rats; the liver first-pass effect of YH1885 in rats was estimated to be approximately 30%. The total body clearance of YH1885 after iv administration of the drug, 5-20 mg kg(-1), to rats were considerably lower than the cardiac output of rats, indicating that the lung and/or heart first-pass effect of YH1885 could be negligible in rats. After oral administration of YH1885, 50 and 100 mg kg(-1), to rats, the F value was approximately 40%, and approximately 15% of the oral dose was recovered from the entire GI tract as unchanged YH1885 at 24 h, and 30% of the oral dose disappeared with the liver first-pass effect. Therefore, the remainder, approximately 15% of the oral dose, could have disappeared with the small intestine first-pass effect and/or degradation of the drug in the GI tract. YH1885 was absorbed from ileum, duodenum, and jejunum of rat, however, YH1885 was under the detection limit in plasma when the drug was instilled into the rat stomach and large intestine. After iv administration of YH1885, 5-20 mg kg(-1), to dogs, the pharmacokinetic parameters of YH1885 also seemed to be independent of the drug at the dose ranges studied. However, after oral administration of YH1885, 0.5 and 2 g per whole body weight, to dogs, the AUC(0-10 h) values were not significantly different (96.8 versus 98.2 microg x min mL(-1)) and this could be due to the poor water-solubility of the drug. YH1885 was not detected in the urine after both iv and oral administration of the drug to both rats and dogs.

Inhibition of vinyl carbamate-induced hepatotoxicity, mutagenicity, and tumorigenicity by isopropyl-2-(1,3-dithietane-2-ylidene)-2-[N-(4-methylthiazol-2- yl)carbamoyl]acetate (YH439)

Isopropyl-2-(1,3-dithietane-2-ylidene)-2-[N-(4-methylthiazol -2-yl)carbamoyl]acetate (YH439) is a novel dithioylidene malonate derivative developed for the treatment of hepatic injury. The compound has been found to down-regulate the expression of hepatic cytochrome P-450 2E1 (CYP2E1) at the transcriptional level (8). Certain organosulfur compounds present in garlic elicit protective effects on chemically induced carcinogenesis and mutagenesis and their chemopreventive activities are associated in part with inhibition of CYP2E1. As part of a program to determine the likely chemopreventive potential of YH439, we initially examined its effects on hepatotoxicity induced by vinyl carbamate (VC), a proximate carcinogen that is preferentially bioactivated by CYP2E1. A single i.p. injection of VC (125 mg/kg body wt) to male Sprague-Dawley rats resulted in severe hepatic lesions as demonstrated by elevated levels of serum enzymes such as alanine aminotransferase and aspartate aminotransferase. Histopathological evaluation of liver sections from VC-treated animals revealed that the hepatic damage mainly consisted of centrilobular necrosis with sinusoidal congestion. Oral administration of YH439 (200 mg/kg body wt) to male Sprague-Dawley rats 2 days, 1 day and 4 h prior to VC completely prevented the hepatic damage caused by this carcinogen. In another experiment, rat hepatic microsome-mediated bacterial mutagenicity of VC was suppressed by YH439 in a dose-related manner. Furthermore, pretreatment of female CD-1 mice with YH439 by gastric intubation resulted in diminution of VC-induced skin carcinogenesis.

Species differences in pharmacokinetics of a hepatoprotective agent, YH439, and its metabolites, M4, M5, and M7, after intravenous and oral administration to rats, rabbits, and dogs

Pharmacokinetic parameters of YH439 and its metabolites, M4, M5, and M7, were compared after iv administration of YH439 to rats (1-10 mg/kg), rabbits (1-10 mg/kg), and dogs (1-20 mg/kg) and oral administration of YH439 to rats (50-500 mg/kg) and dogs (0.5-2 g per whole body weight). After oral administration of YH439 to rats, the F values were 3.67, 1.33, and 0.859% for YH439 oral doses of 100, 300, and 500 mg/kg, respectively. However, the F value increased significantly, 21.2%, after oral administration of YH439-contained mixed micelles (10 mg as free YH439) to rats due to increased water solubility of YH439. Species differences in the pharmacokinetics of YH439 and its metabolites were found. First, M7 was detected in both plasma and urine after both iv and oral administration of YH439 to dogs, whereas it was detected neither in rats nor in rabbits, indicating that considerable amount of M7 was formed from YH439 only in dogs. Second, the AUC (or AUC0-->t) ratios of M4 to YH439 after iv administration of YH439 were 24.6-31.3, 42.2-49.2, and 2200-7640% for rats, rabbits, and dogs, respectively, indicating that formation of M4 after iv administration of YH439 was maximal in dogs. Third, the AUC (or AUC0-->t) ratios of M5 to YH439 after iv administration of YH439 were 103-127, 2.93-3.31, and 92.4-158% for rats, rabbits, and dogs, respectively, indicating that formation of M5 after iv administration of YH439 was minimal in rabbits.

Simultaneous determination of a new hepatoprotective agent, YH439, and its metabolites, M4, M5, and M7 in plasma and urine by high-performance liquid chromatography

A high-performance liquid chromatographic method was developed for the simultaneous determination of YH439, and its metabolites (M4, M5, and M7) in human plasma and rat urine using testosterone as an internal standard. The method involved deproteinization (plasma sample) or extraction (urine sample) followed by injection onto a C18 reversed-phase column. The mobile phase was acetonitrile-0.063 M phosphoric acidisopropyl alcohol (38:48:14, v/v/v), and the flow rate was 1.0 ml/min for the two methods. The column effluent was monitored by a UV detector set at 317 nm. The detection limits for YH439, M4, M5, and M7 in human plasma were 50, 40, 50, and 50 ng/ml, respectively, using the deproteinization method, and the corresponding values in rat urine were 50, 100, 50, and 50 ng/ml using the extraction method. No interferences from endogenous substances were found.

Determination of a new proton pump inhibitor, YH1885, in human plasma and urine by high-performance liquid chromatography

A high-performance liquid chromatographic method was developed for the determination of a new proton pump inhibitor, YH1885 (I), in human plasma and urine, and rat blood and tissue homogenate using fenticonazole as an internal standard. The sample preparation was simple: a 2.5 volume of acetonitrile was added to the biological sample to deproteinize it. A 50-microliter aliquot of the supernatant was injected onto a C8 reversed-phase column. The mobile phase employed was methanol-0.005 M tetrabutylammonium dihydrogenphosphate (77:23, v/v), and it was run at a flow-rate of 1.0 ml/min. The column effluent was monitored using an ultraviolet detector at 270 nm. The retention times for I and the internal standard were 9.0 and 10.3 min, respectively. The detection limits for I in human plasma and urine, and in rat tissue homogenate (including blood) were 50, 100 and 100 ng/ml, respectively. The coefficients of variation of the assay (within- day and between-day) were generally low (below 8.84%) for human plasma and urine, and for rat tissue homogenate. No interferences from endogenous substances were found.

Identification of YH439 and its metabolites in rat urine by gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry

YH439 is a potential drug candidate for the treatment of various hepatic disorders. YH439 and its three metabolites have been identified in rat urine by liquid chromatography-mass spectrometry (LC-MS) and by gas chromatography (GC)-MS. Identification of YH439 and its metabolites was established by comparing their GC retention times and mass spectra with those of the synthesized authentic standards. Both electron impact- and positive chemical ionization MS have been evaluated. The metabolism study was performed in the rat using oral administration of the drug. A major metabolite (YH438) was identified as the N-dealkylation product of YH439. Other identified metabolites were caused by the loss of the methyl thiazolyl amine group (metabolite II) from YH439, the isopropyl hydrogen malonate group (metabolite IV) and the decarboxylated product (metabolite III) of metabolite II.

Establishment of normal values of nasal choanal size in children: comparison of nasal choanal size in children with and without symptoms of nasal obstruction

Twenty-eight pediatric patients between the ages of 2 and 13 years underwent intraoperative measurement of the nasal choanae using an instrument custom designed for this purpose by the Pilling Surgical Instrument Company. Additional data points recorded included age, surgical procedure, and the presence or absence of nasal obstructive symptoms which was determined by carefully questioning parents or guardians. Results were analyzed using linear regression, analysis of variance, and logistic regression. Data supported the following conclusions: (1) a linear relationship exists between age and average choanal size with the choanae enlarging at a rate of 0.208 +/- 0.09 mm per year (P < 0.03, r2 = 0.16); (2) there is no significant difference between the average choanal size in children with and without nasal obstructive symptoms; (3) the size of the posterior choanal air space cannot be used to accurately predict the presence or absence of nasal obstructive symptoms in children between the ages of 2 and 13 years.

Extended use of topical nasal decongestants

Use of sympathomimetic topical nasal decongestants to treat nasal obstruction is usually restricted to 3 to 5 days to avoid potential rebound swelling (rhinitis medicamentosa). In this study, 10 healthy volunteers used oxymetazoline (long-acting topical nasal decongestant) nightly for 4 weeks. Subjects who used antihistamines, oral or topical decongestants, or systemic steroids or who had active sinusitis were excluded from the study. Weekly history, physical examination, and anterior rhinomanometry revealed no adverse effects. Eight (80%) subjects developed nightly nasal obstruction a few hours before the evening dose; the obstruction resolved within 48 hours if no more decongestant was used. All subjects remained responsive to oxymetazoline 4 weeks and 8 weeks after the study began. This finding suggests that long-acting decongestants may be safely used for longer than the recommended 3 to 5 days without adverse effects if used once nightly.

Analysis of mesocarb analogues in urine and plasma of rats by high-performance liquid chromatography and thermospray liquid chromatography-mass spectrometry

The pharmacokinetics and metabolism of synthetic 2-hydroxymesocarb and 4-methyl-2-hydroxymesocarb analyzed by HPLC-DAD and thermospray LC-MS were studied in rats. Multistep liquid-liquid extraction (LLE) was used with diethyl ether at pH 7.0. The major metabolites of 2-hydroxymesocarb in both urine and plasma of the rat were the p-hydroxylated derivative of the phenylcarbamoyl group of the parent drug. The metabolites of 4-methyl-2-hydroxymesocarb in urine of rats may be the oxidized forms at the phenylcarbamoyl group of the parent drug. Absorption (ka) and elimination (ke) rate constants in plasma of 2-hydroxy-mesocarb were 0.0300 and 0.00485 min-1, respectively; those of 4-methyl-2-hydroxymesocarb were 0.0546 and 0.00797 min-1, respectively. The half-lives (t1/2) of 2-hydroxymesocarb and 4-methyl-2-hydroxymesocarb in plasma were 144 and 86 min, respectively.

Suppression of rat hepatic cytochrome P450 2E1 expression by isopropyl 2-(1,3-dithioetane-2-ylidene)-2-[N-(4-methyl-thiazol-2-yl)carbamoyl] acetate (YH439), an experimental hepatoprotectant: protective role against hepatic injury

The expression of cytochromes P450 2E1, P450 2B and P450 1A was examined in rat hepatic tissue in response to YH439, an experimental hepatoprotective agent. P450 2E1 metabolic activities relatively specific for P450 2E1 were decreased up to 57% of control activities in the hepatic microsomes prepared from rats treated with YH439 for 3 days. Immunoblot analyses showed that P450 2E1 levels were decreased below the limit of detectability in hepatic microsomes prepared from YH439-treated rats. YH439 at doses from 25 to 100 mg/kg completely suppressed isoniazid-inducible P450 2E1 levels as monitored by both metabolic activities and immunoblot analysis. RNA hybridization analysis revealed that P450 2E1 mRNA levels failed to change after YH439 treatment. These results demonstrate the YH439 effectively suppresses P450 2E1 expression in the absence of transcriptional inactivation. YH439 failed to affect P450 2B1/2 expression, whereas this agent enhanced the hepatic P450 1A1/2 levels. The hepatoprotective effects of YH439 were also examined. Animals treated with CCl4 and ethanol for 9 weeks showed hepatic injury as demonstrated by 2.5- and 2-fold increases in serum alanine aminotransferase and alkaline phosphatase activities, respectively. Concomitant YH439 treatment resulted in a significant protective effect against the experimental hepatic injury. The toxicant-induced elevation in hepatic hydroxyproline level was completely blocked by YH439 treatment. These data indicate that YH439 suppresses the expression of P450 2E1 and protects the liver against chemical-induced hepatic injury and that the selective modulation of detoxifying enzymes by YH439 may contribute to the protection of liver from xenobiotic-induced intoxication.

Inhibition of covalent DNA binding and mutagenicity of benzo[a]pyrene by isopropyl-2-(1,3-dithietane-2-ylidene)-2-[N-(4-methylthiazol-2-yl) carbamoyl]acetate (YH439), a novel hepatoprotective agent

Isopropyl-2-(1,3-dithietane-2-ylidene)-2[N-(4-methyl-2-thiazol+ ++-2-yl) carbamoyl]acetate (YH439) was synthesized as a hepatoprotective drug for the treatment of chronic hepatitis and liver cirrhosis. In the present investigation, we have tested YH439 for its chemoprotective activity against the carcinogen benzo[a]pyrene. The drug exhibited dose-dependent protection against bacterial mutagenesis induced by benzo[a]pyrene its covalent binding to DNA in vitro mediated by rat hepatic postmitochondrial supernatant enriched with NADPH. The direct mutagenicity of benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide, the ultimate electrophilic and carcinogenic metabolite of benzo[a]pyrene, was also ameliorated by YH439 in a dose-dependent manner. The results of this study suggest that YH439 has a potential as a chemopreventive agent.

Transcriptional inhibition of cytochrome P4502E1 by a synthetic compound, YH439

The molecular mechanism of cytochrome P4502E1 (CYP2E1) inhibition by a synthetic compound, YH439, was studied. In rats treated with YH439, N-nitrosodimethylamine demethylase activity and the amount of immunoreactive CYP2E1 were rapidly decreased in time- and dose-dependent manners. Within 2 h after a single dose of YH439 (150 mg/kg), the CYP2E1-catalyzed activity in uninduced rats was decreased by about 30% and by 43% at 24 h after YH439 injection. YH439 treatment also reduced the elevation of CYP2E1 enzyme activity in starved (induced) animals by 34%. More profound inhibition of CYP2E1 protein levels was observed by immunoblot analysis. The level of CYP2E1 catalytic activity and immunoreactive protein remained suppressed for at least 48 h and returned to normal level at 72 h after YH439 treatment. The levels of immunoreactive CYP2B1/2 protein and catalytic activity were moderately increased while little change was observed in the levels of NADPH-dependent P450 oxidoreductase activity and its protein after treatment with YH439. Unlike competitive inhibitors of CYP2E1, YH439 rapidly (within 2 h) decreased the level of CYP2E1 mRNA, while malotilate, a structural analog of YH439, slightly suppressed its level. Nuclear run-on transcription analyses at 2, 4, and 8 h post-YH439 administration revealed that the inhibition of CYP2E1 by YH439 is at the level of transcription, indicating that YH439 is a new class of CYP2E1 inhibitor. Our data demonstrate that YH439 is a powerful inhibitor of CYP2E1 expression and is thus potentially useful as a pharmacological tool to study CYP2E1 function as well as a potential therapeutic agent.

Prediction of disease-free survival after therapy in Wilms' tumor using nuclear morphometric techniques

The outlook for children with Wilms' tumor has markedly improved with the use of multimodal therapy, and survival currently exceed 85%. Current trends have been to use less intense therapy for children whose tumors have favorable histology (FH). By decreasing the amount of therapy given to patients whose conditions have an excellent chance of responding, the need for accurate criteria to separate high-risk and low-risk groups becomes imperative. Nuclear morphometric techniques have been developed and extensively tested in the author's laboratory. Preliminary studies of FH Wilms' tumors demonstrated the applicability of this technique. Herein, the authors present a retrospective study of 108 patients with FH tumors, with a mean follow-up period of 1,994 +/- 107 days (66 months) for those whose tumors did respond to therapy, and 686 +/- 61 days (23 months) for those whose tumors did not respond. The univariate predictors were age (P = .02), the skewness of nuclear roundness factor (SNRF) (P = .009), and the mean of the lower five values for nuclear ellipticity, measured by the feret diameter method (L5EFD) (P = .01). A multivariate analysis combining all three variables better separated the two groups (P = .00016). A probability function curve was constructed to predict poor prognosis. Kaplan-Meier actuarial survival analysis was used to predict disease-free survival as clinical progression, and separated the two groups (P = .0004, Wilcoxon-Gehan statistic). These results suggest that nuclear morphometry is useful in the initial assessment of patients with Wilms' tumor.

Phenytoin induction of cytochrome P4502B in mice: effects on hexobarbital hydroxylase activity

1. Treatment of ICR and C57BL/6 mice with phenytoin (50 mg/kg, i.p., 3 days) resulted in approximately 33 and 43% increases in hepatic cytochrome P450 levels relative to uninduced microsomes, respectively. Phenytoin treatment caused a 63% decrease in hexobarbital sleeping time in ICR mice (19 versus 52 min). 2. Both Western immunoblot analysis and solid phase radioimmunoassay using monoclonal anti-rat P4502B antibody showed that P4502B was increased significantly in phenytoin-induced mouse microsomes compared with uninduced mice. P4502B9 was the predominantly induced form whereas 2B10 was elevated marginally. Phenytoin was as efficacious as phenobarbital in increasing P4502B. 3. Phenytoin treatment resulted in an approximately 8-fold increase in hexobarbital hydroxylase activity whereas phenobarbital treatment caused an approximately 13-fold increase. Addition of anti-P4502B antibody produced complete inhibition of hexobarbital oxidation in phenytoin-induced microsomes, indicating that raised P4502B in phenytoin-induced microsomes is associated with the increased hexobarbital hydroxylase activity. 4. Phenytoin failed to increase P4501A in either C57BL/6 or ICR mice, as assessed by both immunoblot analysis and metabolic activities. Although both aryl hydrocarbon hydroxylase and 7-ethoxycoumarin deethylase activities were raised approximately two-fold following phenytoin treatment, the metabolic activities were not inhibited by anti-P4501A antibody. 5. These results provide evidence that phenytoin induces P4502B in mice with pronounced increase in hexobarbital hydroxylase activity, and fails to induce P4501A in either C57BL/6 or ICR mice.

Characterization of the antiplasmin activity of human thrombospondin-1 in solution

These studies demonstrate relatively rapid association of plasmin with thrombospondin and the effects of this interaction on plasmin activity towards D-Val-L-Leu-L-Lys p-nitroanilide hydrochloride (S-2251) and the proteinase inhibitors alpha 2-antiplasmin (alpha 2AP) and alpha 2-macroglobulin (alpha 2M). Binding of plasmin to thrombospondin reached an apparent reversible equilibrium within 3 min at 22 degrees C. The amidase activity of bound plasmin was inhibited. An analysis of S-2251 hydrolysis indicated that thrombospondin is a linear mixed-type plasmin inhibitor. The dissociation constant (KD) for the binding of plasmin to thrombospondin was 0.5 microM, assuming one plasmin binding site per thrombospondin homotrimer. Plasmin and miniplasmin slowly cleaved thrombospondin, yielding products which were comparable with those generated by other proteinases. Tranexamic acid inhibited the digestion of thrombospondin by plasmin and miniplasmin, suggesting an important role for the kringle-5 domain in this process. When plasmin was incubated first with thrombospondin and then with alpha 2AP, plasmin that was apparently bound to thrombospondin reacted with alpha 2AP at a decreased rate; however, within 20 min, all of the plasmin was recovered in complex with alpha 2AP. Similar results were obtained with alpha 2M. Transfer of plasmin from thrombospondin to alpha 2AP or alpha 2M probably required plasmin-thrombospondin-complex dissociation. A low level of reaction of alpha 2AP with thrombospondin-associated plasmin could not be ruled out. These results demonstrate that the activity of plasmin, when bound to thrombospondin, is greatly diminished or eliminated. The plasmin-thrombospondin complex, which is formed within 3 min, is fully reversible and the associated plasmin is in a latent form protected from proteinase inhibitors. Therefore, thrombospondin may regulate plasmin activity in a manner which is distinct from conventional proteinase inhibitors and other extracellular-matrix proteins.

Link between Helicobacter pylori-associated gastritis and duodenal ulcer

We examined the interrelationships among the degree of fundic mucosal atrophy, the prevalence of Helicobacter pylori in the gastric antrum, the gastric juice, and the duodenum with and without gastric metaplasia, in 20 duodenal ulcer patients and 20 non-duodenal ulcer patients. The detection rates of H. pylori in the antrum, the gastric juice, and the duodenum were significantly higher in duodenal ulcer patients (80%, 65%, and 60%) than in non-duodenal ulcer subjects (50%, 20%, and 5%). The frequency of H. pylori was significantly lower in the gastric juice (30%) and the duodenum (10%) in non-duodenal ulcer patients with antral H. pylori, compared with those in duodenal ulcer patients with antral H. pylori. All of seven patients with both gastric metaplasia and H. pylori infection in the duodenum had duodenal ulcer, whereas only 1 of 14 patients without either gastric metaplasia or H. pylori infection in the duodenum had duodenal ulcer. There was normal or mild atrophic mucosa in the fundus of duodenal ulcer patients with H. pylori in the antrum, whereas moderate or severe atrophic mucosa in non-duodenal ulcer patients with H. pylori gastritis. These results suggest that the preserved fundic mucosa, gastric metaplasia in the duodenum, and a greater load of H. pylori to the duodenum through the gastric juice may be prerequisites for the formation of duodenal ulcers.

The use of nuclear morphometry to predict prognosis in pediatric urologic malignancies: a review

Wilms tumor, the most common pediatric urologic malignancy, and genitourinary rhabdomyosarcoma, the most common soft tissue sarcoma of childhood, represent two of the most commonly diagnosed pediatric urologic malignancies. The introduction and use of multimodal therapy (surgery, radiation, and chemotherapy) by the National Wilms Tumor Study (NWTS) and the Intergroup Rhabdomyosarcoma Study (IRS) groups have greatly improved the survival among children with these malignancies. Present survival rates for Wilms tumor exceed 85% and for rhabdomyosarcoma survival rates are approaching 80% as well. For Wilms tumor, current treatment trends suggest less intense therapy for those children with favorable histology tumors who are considered at relatively low risk for tumor recurrence. Likewise, the significant morbidity associated with the present therapy regimens for rhabdomyosarcomas has prompted investigators to search for individualized management schemes for children with a high probability of responding. The need for accurate criteria to separate these high and low risk groups becomes imperative. In this review we present our work using nuclear morphometry, as a prognostic indicator, to retrospectively predict response to therapy for children with Wilms tumors and genitourinary rhabdomyosarcomas.

Generation of ammonia and mucosal lesion formation following hydrolysis of urea by urease in the rat stomach

We examined the morphological changes in gastric mucosa and the generation of ammonia after exposure of the rat stomach to urea in the presence of urease, in attempts to investigate a pathophysiological role of urea, urease, and ammonia system in gastric ulcer diseases. Exposure of the stomach for 20 min to 2 ml urea (0.025-0.2%) together with urease (100 IU) induced histological damages in a concentration-related manner. Either urea or urease alone did not induce any histological change in the mucosa. Instillation of urea into the stomach generated ammonia in the presence of urease; the amount of ammonia was increased depending on the concentration of urea, and was closely associated with the severity of histological damage. The exposure of the stomach to ammonia (NH4OH: 0.01-0.1%) also produced histological damages in the gastric mucosa in a concentration-related manner. The characteristics of injury induced by 0.5-1.0% ammonia were stasis of microcirculation, disruption of the surface epithelial cells, and necrosis of the mucosa. These results demonstrated that ammonia generated from the hydrolysis of urea by urease in the stomach causes damages in the gastric mucosa.

Protective effect of taurine against ammonia-induced gastric mucosal lesions in rats

We examined the role of gastric ammonia in the development of gastric lesions in rats. Exposure of the gastric mucosa to ammonia (30 mM) produced microscopic injury, but no macroscopic lesion was observed. However, exposure of the stomach to ammonia in rats subjected to ischemia resulted in macroscopic gastric lesions. The macroscopic lesions were markedly inhibited by pretreatment with taurine, a scavenger of hypochlorous acid (HOCI) and monochloramine (NH2Cl). These results indicate that ammonia is deleterious to gastric mucosa, and monochloramine may be involved in the pathogenesis of ammonia-induced mucosal lesions.

Effects of ammonia on the gastric mucosal barrier in rats and dogs

We examined the effect of ammonia on the gastric mucosal barrier by measuring the changes in transmucosal fluxes of H+, Na+ and K+. In rats, ammonia at concentrations of 0.1 to 0.5% increased the H+ loss from the lumen and 0.2 to 0.5% concentrations of ammonia increased both Na+ and K+ influxes into the lumen. In dogs, in an exactly similar manner to rats, ammonia at concentrations of 0.1 to 0.5% increased H+ loss, and ammonia at concentration of 0.5% increased both Na+ and K+ influxes into the lumen. These results suggest that ammonia breaks the gastric mucosal barrier.

[Evaluation of the laser-Doppler velocimetry method in the measurement of gastric blood flow in rats--spatial resolution]

In this paper, gastric blood flow in rats was measured with the laser-Doppler velocimetry method (the LDV method) to study about the tissue locus where its flow signal arises (spatial resolution). In the measurement throughout some 1 mm thickness of another nonperfused gastric wall interposed between the laser probe and gastric mucosal surface, its laser flow signal was 17% of the flow signal in the usual measurement. In the blood flow measurement with the LDV prove on the mucosal and the serosal surface of gastric wall, the laser flow signal on the mucosal surface was higher (p less than 0.05) than that on the serosal surface. These results suggested that the laser flow signal mainly arose from the tissue right under the laser probe, reflecting the total gastric blood flow of the gastric wall. In the regional blood flow measurement at corpus and antrum, the ratio between antral and corpus flow signals by the LDV method was similar to that between gastric mucosal blood flows at both sites by the hydrogen gas clearance technique. In the blood flow measurement after the intravenous infusion of each pentagastrin, isoproterenol, and vasopressin, flow signal of the LDV method could detect the each effect of these drugs on gastric mucosal blood flow as well as well as the hydrogen gas clearance technique. These results showed that the laser flow signal and gastric mucosal blood flow were mutually correlated.(ABSTRACT TRUNCATED AT 250 WORDS)

Cytoprotective effect of plasmin inhibitor on necrotizing agent-induced gastric lesions in rats

We studied the effect of plasmin inhibitor on ethanol and ammonia-induced gastric mucosal lesions in rats using an ex vivo chamber. Tranexamic acid and aminocaproic acid significantly inhibited macroscopic gastric hemorrhagic necrosis and attenuated the decrease of gastric transmucosal potential difference induced by 50% ethanol and 1% ammonia. The protection of gastric mucosa afforded by tranexamic acid and aminocaproic acid was not affected by pretreatment with indomethacin (5 mg/kg). These results suggest that plasmin inhibitor plays an important role in the prevention of gastric deep necrosis following exposure of the stomach to a damaging agent.

Effect of diethyldithiocarbamate on gastric and duodenal mucosal blood flow and vascular permeability in rats

Diethyldithiocarbamate (DDC), an inhibitor of superoxide dismutase, produced ulceration in the proximal duodenum of rats, and erosions or ulcers in the stomach. DDC given s. c. at 1.5 g/kg increased duodenal and gastric vascular permeability, and reduced blood flow. The decrease in gastric blood flow caused by DDC was attenuated by pretreatment with superoxide dismutase, and significantly inhibited by a xanthine oxidase inhibitor, allopurinol. It is suggested that the superoxide and other radicals damage the mucosal vasculature, and play a role in the pathogenesis of gastric and duodenal mucosal lesions.

Effect of plasmin inhibitors on gastric mucosal permeability in rats

We examined the protective effect of plasmin inhibitors on gastric mucosal vascular permeability in rats. Tranexamic acid and aminocaproic acid significantly inhibited the increase in vascular permeability and macroscopic gastric mucosal lesions induced by 50% ethanol and 1% ammonia. The protective effect afforded by plasmin inhibitors was not affected by pretreatment with indomethacin. Our results show that plasmin inhibitors inhibit the increase in gastric vascular permeability and suggest that plasmin may play an important role in the pathogenesis of gastric mucosal damage.

Effects of 16,16-dimethyl-prostaglandin E2 on ammonia- and ethanol-induced mucosal lesions in the rat

The effect of necrotizing agents, such as ammonia and ethanol, on the gastric mucosa was compared. Intragastric administration of ammonia (0.6-1.0%) and ethanol (60-100%) produced hemorrhagic necrosis of gastric mucosa in a concentration-dependent manner. In the anesthetized rat, the macroscopic lesions induced by ethanol were significantly inhibited by pretreatment with 3 or 10 micrograms/kg of 16,16-dmPGE2, but the lesions induced by ammonia were not inhibited by either 3 or 10 micrograms/kg of 16,16-dmPGE2 in the anesthetized rat. The decrease of gastric transmucosal potential difference and mucosal blood flow produced by ethanol (100%) were significantly attenuated by 16,16-dmPGE2; however, those produced by ammonia (1%) were not inhibited by 16,16-dmPGE2 in the anesthetized rat. In conscious rats, ammonia-induced lesions were not inhibited by pretreatment with 3 micrograms/kg of 16,16-dmPGE2 but they were significantly reduced by the pretreatment of 10 micrograms/kg of 16,16-dmPGE2. These results show that 16,16-dmPGE2 afforded little protection against ammonia-induced gastric lesions in the anesthetized rat and suggest that a different mechanism is involved in the development of gastric mucosal lesions between those induced by ethanol and those induced by ammonia.