Role of extracellular adenosine triphosphate in the cytotoxic T- lymphocyte-mediated lysis of antigen presenting cells

The lysis of antigen presenting cells (APCs) by cytotoxic T lymphocytes (CTLs) may be one mechanism whereby an immune response is downregulated by Staphylococcus superantigens. Disappearance of monocytes/macrophages from staphylococcal enterotoxin A (SEA)-activated peripheral blood mononuclear cell (PBMC) cultures, but not from control PBMC cultures was seen by flow cytometry. Recently, adenosine triphosphate (ATP) has been described as an effector molecule in CTL-mediated lysis of some murine tumor target cells. We have also shown that ATP caused the lysis of human macrophages, and that treatment of cells with interferon gamma (IFN gamma) rendered macrophages significantly more sensitive to ATP than untreated cells. To show that this purine nucleotide may play a role in modulating the immune system, we generated human CTLs that were stimulated with SEA, and used them as effector cells against SEA-pulsed autologous macrophages. CTLs were found to specifically lyse SEA-pulsed macrophages, while control, unpulsed, macrophages were unaffected. The addition of hexokinase, an enzyme that hydrolyzes ATP, significantly abrogated the killing of SEA-pulsed cells during the assay. In examining the mechanism of cytotoxicity, electron microscopy showed that macrophages incubated with both ATP and CTLs underwent necrosis, rather than apoptosis. From these results, it is suggested that ATP is released from CTLs during antigen presentation, and that IFN gamma- activated macrophages, which are inherently more sensitive to this mediator, are readily lysed and therefore removed from circulation, thus downregulating an immune response.     

Allogeneic bone marrow transplantation for chronic myeloid leukemia in first chronic phase: a randomized trial of busulfan-cytoxan versus cytoxan-total body irradiation as preparative regimen: a report from the French Society of Bone Marrow Graft (SFGM)

From March 1988 to March 1991, 19 French bone marrow transplant (BMT) centers participated in a prospective randomized trial comparing two conditioning regimens for patients with chronic myeloid leukemia transplanted in first chronic phase with an HLA identical sibling donor. A total of 120 consecutive patients were randomized to receive either 120 mg/kg of cyclophosphamide followed by total body irradiation (CY-TBI; n = 55) or 16 mg/kg of busulfan followed by 120 mg/kg of CY (BU-CY; n = 65). Two different TBI regimens were used. Thirteen patients received a 10-Gy single-dose TBI (SDTBI), and 42 received a fractionated TBI (FTBI). Median time between diagnosis and BMT was 315 days. Overall 5-year actuarial survival was 62.9% (65.8% +/- 12.5% for CY-TBI and 60.6 +/- 11.7% for BU-CY; P = .5), and overall disease-free survival was 55% (51% +/- 14% for CY-TBI and 59.1% +/- 11.8% for BU-CY; P = .75). All patients conditioned with CY-TBI experienced sustained engraftment; in contrast, 4 of 65 patients conditioned with BU-CY rejected the graft (P = .18). There was no significant statistical difference between the two groups regarding transplant-related mortality (29% for CY-TBI and 38% for BU-CY; P = .44). So far, with a median follow up of 42 months, 11 patients have relapsed; 9 relapses occurred after CY-TBI, mostly after FTBI (8 of 9) and 2 after BU-CY (P = .02). The actuarial risk of relapse was 4.4% +/- 6.7% after BU-CY, 11.1% +/- 20.8% after SDTBI, and 31.3% +/- 18.1% after FTBI (P = .039). In addition, independently of the conditioning regimen, the increase of posttransplant immunosuppression in 16 patients with an anti- interleukin-2 receptor monoclonal antibody (MoAb) in addition to a short course of methotrexate and cyclosporine was shown to increase the actuarial risk of relapse (57% +/- 30% with MoAb v 9% +/- 7.3% without MoAb; P = .001). We conclude that BU is an acceptable alternative to TBI for patients with chronic myeloid leukemia in first chronic phase receiving BMT from HLA identical sibling donors. Both BU-CY and CY-TBI regimens gave similar transplant-related mortality, and the antileukemic efficiency of BU-CY regimen was either similar or even higher than that of CY-TBI.     

HLA Antigens and Nontuberculous Mycobacterial Lung Disease in Korean Patients

Background  Human leukocyte antigen (HLA) molecules are known to play an important role in host-defense mechanisms. The aim of this study was to evaluate the association between HLA alleles and lung disease caused by nontuberculous mycobacteria (NTM) in Korean patients. Methods  Seventy-eight patients with NTM lung disease (48 patients with Mycobacterium avium-intracellulare complex [MAC] infection and 30 patients with Mycobacterium abscessus infection) were included in the study. HLA-A, -B, and -DRB1 genotyping was performed by polymerase chain reaction using sequence-specific primers. Data from 485 healthy Korean individuals were used as a control. Results  When compared to controls, patients with NTM lung disease showed an increased frequency of DRB1*11 (OR = 1.91, 95% confidence interval [CI] = 1.01–3.64, p = 0.045, corrected p [pC] > 0.05). In the subgroup analysis, patients with MAC lung disease had an increased frequency of B*46 (OR = 2.23, 95% CI = 1.05–4.73, p = 0.044, pC > 0.05). Conclusions  Our data suggest that in a Korean population, patients with NTM lung disease and healthy subjects differ in the frequencies of some HLA alleles. However, when considering corrected p values, our findings are inconclusive. S.-W. Um and C.-S. Ki contributed equally to this work.     

Detection of serum TNF-α,IFN-γ,IL-6 and IL-8 in patients with hepatitis B

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The Effects of Combined Treatment with an HMG-CoA Reductase Inhibitor and PPARγ Agonist on the Activation of Rat Pancreatic Stellate Cells

Background/Aims

Hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors (statins) and peroxisome proliferator-activated receptor gamma (PPARγ) ligands can modulate cellular differentiation, proliferation, and apoptosis through various pathways. It has been shown that HMG-CoA reductase inhibitors and PPARγ agonists separately inhibit pancreatic stellate cell (PaSC) activation. We studied the effects of a combination of both types of drugs on activated PaSCs via platelet-derived growth factor (PDGF), which has not previously been reported. The present study was performed to elucidate the underlying mechanisms of these effects by focusing on the impact of the signaling associated with cell-cycle progression.

Methods

Primary cultures of rat PaSCs were exposed to simvastatin and troglitazone. Proliferation was quantified using the BrdU method, and cell-cycle analysis was performed using a fluorescent activated cell sorter. The protein expression levels of smooth muscle actin (SMA), extracellular signal-regulated kinase (ERK), and a cell cycle machinery protein (p27Kip1) were investigated using Western blot analysis.

Results

Simvastatin reversed the effects of PDGF on cell proliferation in a dose-dependent manner. The combination of a low concentration of simvastatin (1 mM) and troglitazone (10 mM) synergistically reversed the effects of PDGF on cell proliferation but had no effect on cell viability. The expression of a-SMA was markedly attenuated by combining the two drugs, which blocked the cell cycle beyond the G0/G1 phase by reducing the levels of phosphorylated ERK and reversed the expression of p27Kip1 interrupted by PDGF.

Conclusions

Simvastatin and troglitazone synergistically inhibited cell proliferation in activated PaSCs by blocking the cell cycle beyond the G0/G1 phase. This inhibition was due to the synergistic modulation of the ERK pathway and the cell cycle machinery protein p27Kip1.     

Is Intercellular Space Different Among Layers in Normal Esophageal Mucosa? An Electron Microscopic Study

Background/Introduction

Dilatation of intercellular space (IS) of esophageal epithelial cells is described as a sensitive early marker for epithelial damage by refluxate. Esophageal epithelia are morphologically subdivided into three layers according to the shape of the cells and nuclei. Meanwhile, ten transmission electron microscopy (TEM) photographs and ten randomly selected measurements per photo from gastroesophageal reflux disease (GERD) patients have been widely accepted without any theoretical criticism. We assumed that the IS differs among each layer and thus studied IS according to subdivided layers of normal esophageal epithelium. We also evaluated an optimal number of IS measurements per photograph.

Materials and Methods

Esophagogastroduodenoscopy was performed in 15 healthy adults without any symptom of GERD, taking biopsies from mucosa above 5 cm from the squamo-columnar junction. Tissues were handled and prepared for TEM, verifying three layers of esophageal mucosa, i.e., squamous cell layer, prickle cell layer, and basal layer. Ten digital photomicrographs were taken from each three layers by TEM, and ISs were measured with a computerized image analysis program. For the method of measuring IS, 5, 10, 20, 30, and 40 measurements per photomicrograph were respectively performed by four different examiners. Mean value and intraclass correlation coefficient (ICC) was also yielded.

Results

Mean IS of lower esophagus irrelevant to three epithelial layers were 0.39 ± 0.30 ??m. When subdivided into three layers, however, mean IS of squamous cell layer was 0.62 ± 0.23 ??m, prickle cell layer 0.23 ± 0.19 ??m, and basal layer 0.55 ± 0.36 ??m, with their difference statistically significant (p < 0.05). On the other hand, ICC of 5, 10, 20, 30, and 40 measurements were 0.688, 0.917, 0.837, 0.790, and 0.765, respectively.

Conclusions

Mean IS values of each three layers of esophageal epithelium in normal subjects were significantly different, and reconsideration of the standard measurement method is needed. Ten measurements per photo had an adequate inter-observer agreement.     

Radiotherapy for 65 patients with advanced unresectable hepatocellular carcinoma

AIM： To evaluate the efficacy of radiotherapy （RT） in patients with advanced unresectable hepatocellular carcinoma （HCC）. METHODS： A total of 65 patients were treated with RT in the Korea University Medical Center. The median age of the patients was 60 years, and 86.2% were men. 18.5% and 81.5% of the patients were diagnosed as TNM stage Ⅲ and Ⅳ-A, respectively. Treatment response was assessed 4 mo after initiation of RT. Tumor regression rate 1 mo after initiation of RT （TRR1m） was also assessed. Duration of survival was calculated from the initiation of RT. RESULTS： The objective treatment response was 56.9%. The 12 mo survival rate was 34.7%. Predictive factors for survival were Child-Pugh grade, α-fetoprotein level and treatment response. An objective response was achieved more frequently in patients with TRR1m ≥ 20% than in those with TRR1m 〈 20% （P 〈 0.001）. CONCLUSION： RT is effective in treating advanced HCC with a tumor response rate of 56.9%.     

Circulating endothelial and endothelial progenitor cells in patients with severe sepsis

Elevated circulating endothelial cell (CEC) and circulating endothelial progenitor cell (CEPC) counts may indicate vascular damage and disease status, but data on these cell populations in patients with severe sepsis are limited. This study compared CEC and CEPC counts in patients with and without severe sepsis following intensive care unit (ICU) admission. Venous blood samples were collected within 24 h, 48-72 h, and 120-144 h. Baseline demographics, 28-day mortality, ICU and hospital days, and Sequential Organ Failure Assessment (SOFA) scores were recorded. Patients with (n = 18) and without (n = 28) severe sepsis were balanced for mean age (63.7 and 61.3 years, respectively) and gender. There were no differences in 28-day mortality, ICU days, or hospital days. Baseline SOFA scores were higher in the sepsis group. At 48-72 h, patients with severe sepsis had significantly higher median CEC counts (51.5 vs. 28.0 cells/4 ml of blood, P = 0.02). CEC values for all ICU patients were significantly (P < 0.05) higher than in healthy volunteers. CEPC counts in both cohorts ranged from 0 to > 21 colonies/4 ml blood (mean = 1.13 ± 2.25; median = 0) without significant differences at any time point. This study demonstrates the ability to quantify CECs and CEPCs using consensus methodology. Understanding the relationship between CEC/CEPC counts and outcomes may provide insight into the mechanisms of endothelial cell changes in severe sepsis.     

Effect of Bowel Preparation with Polyethylene Glycol on Quality of Capsule Endoscopy

Background and Aims  

Capsule endoscopy (CE) has the problem that lumen visualization is impaired by bubbles, bile, and debris. The benefits of bowel preparation are still controversial and the best method remains to be determined. The objective of this study was to evaluate the effect of the method of bowel preparation on the quality of visualization and on transit time.