Continuing increased risk of oral/esophageal cancer after allogeneic hematopoietic stem cell transplantation in adults in association with chronic graft-versus-host disease.

BACKGROUND: The number of long-term survivors after hematopoietic stem cell transplantation (HSCT) showed steady increase in the past two decades. Second malignancies after HSCT are a devastating late complication. We analyzed the incidence of, risk compared with that in the general population, and risk factors for secondary solid cancers. PATIENTS AND METHODS: Patients were 17 545 adult recipients of a first allogeneic stem cell transplantation between 1990 and 2007 in Japan. Risks of developing secondary solid tumors were compared with general population by using standard incidence ratios (SIRs). RESULTS: Two-hundred sixty-nine secondary solid cancers were identified. The cumulative incidence was 0.7% [95% confidence interval (CI), 0.6%-0.9%] at 5 years and 1.7% (95% CI, 1.4%-1.9%) at 10 years after transplant. The risk was significantly higher than that in the general population (SIR=1.8, 95% CI, 1.5-2.0). Risk was higher for oral cancer (SIR=15.7, 95% CI, 12.1-20.1), esophageal cancer (SIR=8.5, 95% CI, 6.1-11.5), colon cancer (SIR=1.9, 95% CI, 1.2-2.7), skin cancer (SIR=7.2, 95% CI, 3.9-12.4), and brain/nervous system cancer (SIR=4.1, 95% CI, 1.6-8.4). The risk of developing oral, esophageal, or skin cancer was higher at all times after 1-year post-transplant. Extensive-type chronic graft-versus-host disease (GVHD) was a significant risk factor for the development of all solid tumors (RR=1.8, P<0.001), as well as for oral (RR=2.9, P<0.001) and esophageal (RR=5.3, P<0.001) cancers. Limited-type chronic GVHD was an independent risk factor for skin cancers (RR=5.8, P=0.016). CONCLUSION: Recipients of allogeneic HSCT had a significantly higher ∼2-fold risk of developing secondary solid cancers than the general population. Lifelong screening for high-risk organ sites, especially oral or esophageal cancers, is important for recipients with active, or a history of, chronic GVHD.

Clinical features and risk factors for developing varicella zoster virus dissemination following hematopoietic stem cell transplantation.

BACKGROUND: We retrospectively analyzed 80 instances of varicella zoster virus (VZV) disease in 72 patients who underwent allogeneic hematopoietic stem cell transplantation (HSCT) and examined the clinical differences between localized and disseminated disease. Risk factors for developing VZV dissemination were also evaluated. RESULTS: Of the 80 instances, 54 instances were localized diseases and 26 were disseminated diseases. Patient characteristics did not differ significantly between the 2 groups, except for the first-line therapy and the duration from symptom onset to treatment. In the disseminated group, intravenous acyclovir was used as the first-line therapy more frequently, and more time elapsed before beginning antiviral therapy compared with the localized group. In multivariate analyses, the duration from symptom onset to treatment was identified as an independent risk factor that significantly affected the development of VZV dissemination. Gender, total body irradiation, and chronic graft-versus-host disease, of which the latter 2 factors were reported as risk factors for the development of VZV disease after HSCT, did not affect the development of VZV dissemination. CONCLUSION: Our results suggest that VZV infection or reactivation may easily progress to viremia with delayed use of antiviral agents and may result in VZV dissemination in immunocompromised patients.

Impact of a donor source on adult Philadelphia chromosome-negative acute lymphoblastic leukemia: a retrospective analysis from the Adult Acute Lymphoblastic Leukemia Working Group of the Japan Society for Hematopoietic Cell Transplantation.

BACKGROUND: We aimed to clarify the impact of the donor source of allogeneic stem cell transplantation (allo-SCT) on Philadelphia chromosome-negative acute lymphoblastic leukemia [Ph(-) ALL] with focus on cord blood (CB). PATIENTS AND METHODS: We retrospectively analyzed data of 1726 patients who underwent myeloablative allo-SCT for adult Ph(-) ALL. The sources of the allo-SCT were related donors (RD; N = 684), unrelated donors (URD; N = 809), and CB (N = 233). RESULTS: Overall survival (OS) in patients after CB allo-SCT in first complete remission (CR1) was comparable with that after RD or URD allo-SCT (RD: 65%, URD: 64% and CB: 57% at 4 years, P = 0.11). CB was not a significant risk factor for relapse or non-relapse mortality as well as for OS in multivariate analyses. Similarly, the donor source was not a significant risk factor for OS in subsequent CR or non-CR (RD: 47%, URD: 39% and CB: 48% in subsequent CR, P = 0.33; RD: 15%, URD: 21% and CB: 18% in non-CR, P = 0.20 at 4 years). CONCLUSION: Allo-SCT using CB led to OS similar to those of RD or URD in any disease status. To avoid missing the appropriate timing, CB is a favorable alternative source for adult Ph(-) ALL patients without a suitable RD or URD.

Visceral varicella zoster virus infection after allogeneic stem cell transplantation.

INTRODUCTION: Varicella zoster virus (VZV) disease is one of the major infectious complications that can occur after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Many reports have shown visceral VZV infection, a special type of VZV disease, to be rare. However, few studies so far have included a large number of patients. FINDINGS: Visceral VZV infection was found in 20 (0.8%) of 2411 patients who underwent allo-HSCT at our hospitals. Seventeen (85%) patients were taking immunosuppressive agents at the time of presentation with zoster. The presenting symptom was abdominal pain in 16 patients (80%), unconsciousness in 3 patients (15%), and no symptoms in 1 patient. The mean time interval from allo-HSCT to symptomatic visceral VZV infection was 273 days (103-800 days). The eruptions appeared within 3 days (0-13) after the first symptoms. Treatment with intravenous acyclovir was initiated before the appearance of eruptions in 3 of 18 patients (all 3 survived) with vesicular eruptions, the same day in 12 patients (11 survived, 1 died), and after the appearance in 3 patients (1 survived, 2 died). The overall mortality was 20%. CONCLUSION: In conclusion, these data confirm that the incidence of visceral VZV infection is infrequent, but this disease is serious. When patients being treated with immunosuppressive agents demonstrate abdominal pain or unconsciousness, the possibility of visceral VZV infection should be considered as well as earlier therapeutic intervention.

Introduction and evaluation of computer-assisted education in an undergraduate dental hygiene course.

OBJECTIVE: This paper introduced newly developed computer-assisted learning materials and reports of a survey of junior college dental hygiene students who have used them. METHODS: We authored new educational material to promote students' basic dental hygiene practice skills using a simulation software generator. A set of five developed materials were tested by 43 female second-year dental hygiene students during the second semester at a college in Chiba, Japan. The evaluation was conducted in the form of a questionnaire including open-ended questions. Students' opinions were analysed using characteristic diagrams, a troubleshooting tool that can be used to visually illustrate the causes and effects of a problem. RESULT: The overall results of the evaluation were positive. The students were given five sets of simulation learning materials (SLMs). Eighty-three percent of the students felt that they could carry out independent study of clinical practice better after the virtual practice. Ninety-three percent of them felt that the exercises should be continued in the future, and eighty-eight percent of them felt that this virtual practice deepened their interest in other classes and training sessions. All of the students found the virtual practice beneficial for their learning. DISCUSSION: The present results suggest that the students became conscious of their lack of knowledge through SLMs. These findings indicate that SLMs for practicing basic clinical procedures is beneficial.

Allo-SCT using reduced-intensity conditioning against advanced pancreatic cancer: a Japanese survey.

Pancreatic cancer is a frequent cause of cancer-related mortality and has an extremely poor prognosis. To evaluate the efficacy of allogeneic hematopoietic SCT with reduced-intensity conditioning (RICT) against pancreatic cancer, we analyzed the clinical data of 22 patients. After a fludarabine-based conditioning regimen followed by the infusion of PBSCs, all but two achieved engraftment. Complete, partial and minor response was observed in 1, 2 and 2 patients, respectively, with an overall response rate of 23%. Median survival was only 139 days and the major cause of death was tumor progression. Poor performance status before RICT and a lower number of infused CD34-positive cells were associated with shorter survival after RICT. Patients who developed chronic GVHD tended to survive longer than those who did not. These findings support the investigation of a novel treatment strategy to enhance the immunological effect against pancreatic cancer.

Clinical features of allogeneic hematopoietic stem cell transplantation-associated organizing pneumonia.

We describe the clinical courses and outcomes of allogeneic hematopoietic stem cell transplantation-associated organizing pneumonia (HOP) observed in our institution over the past 20 years. Charts and chest radiographs of 603 allogeneic transplant recipients were retrospectively reviewed for HOP. In total, 12 cases of HOP were identified (2.0%) at a median interval of 148 days after transplantation (range, 53-475 days), presenting with low-grade fever, nonproductive cough and dyspnea at onset. Initial antibiotic treatment did not ameliorate symptoms, but most patients responded well to 0.5-1 mg/kg of prednisolone. HOP flare-up occurred after discontinuing treatment or while tapering doses in 9 of 12 patients, but responded to re-treatment with the initial dose of steroid. Although three patients died, no deaths were attributable to pulmonary failure. The remaining nine patients displayed no relapse of primary disease and 5-year survival rate was 74.1%. Clinical features of the 12 patients were similar in that all underwent irradiation-containing conditioning and most had a prior history of acute graft-versus-host disease (GVHD) and cytomegalovirus (CMV) infection. Furthermore, eight patients had active chronic GVHD at onset of HOP. These findings suggest that factors such as irradiation-containing regimens, previous CMV infection and allogeneic immune reaction may contribute to HOP occurrence.

Value of chemotherapy before allogeneic hematopoietic stem cell transplantation from an HLA-identical sibling donor for myelodysplastic syndrome.

Allogeneic hematopoietic stem cell transplantation (allo-SCT) is a curative treatment for myelodysplastic syndrome (MDS). The object of this study was to evaluate the impact of chemotherapy before allo-SCT. We analyzed the data of 283 patients who underwent allo-SCT from an HLA-identical sibling donor for MDS that were reported to the Japan Society for Hematopoietic Cell Transplantation. The cumulative incidence of grade II-IV acute GVHD was 33%. Overall survival (OS) at 5 and 10 years was 48.8 and 42.5%, respectively. Multivariate analyses identified karyotype, FAB classification, and the history of chemotherapy before allo-SCT as significant predictors for OS. OS at 5 years was 57% for patients who underwent allo-SCT as a primary treatment for refractory anemia with excess blasts in transformation (RAEB-t) or secondary acute myeloid leukemia (AML) and 54% for those who underwent allo-SCT in remission after induction chemotherapy (P=0.81). The proportion of patients with a poor karyotype was equivalent between the two groups (P=0.44). Although only a randomized controlled trial will be able to establish a definite conclusion, these results do not support the administration of induction chemotherapy for patients with RAEB-t or secondary AML before allo-SCT.

Randomized trials between behenoyl cytarabine and cytarabine in combination induction and consolidation therapy, and with or without ubenimex after maintenance/intensification therapy in adult acute myeloid leukemia. The Japan Leukemia Study Group.

PURPOSE: We analyzed complete remission (CR), disease-free survival (DFS), and event-free survival (EFS) rates in two groups of patients treated with either N4-behenoyl-1-beta-D-arabinosylcytosine (BHAC) or cytarabine, and analyzed DFS with or without ubenimex, a biologic response modifier. PATIENTS AND METHODS: Newly diagnosed patients with acute myeloid leukemia (AML) were randomized to receive either BHAC or cytarabine as remission-induction combination chemotherapy and two courses of consolidation therapy. After maintenance/intensification therapy, patients in CR were randomized to receive either ubenimex and no drug. RESULTS: Of 341 patients registered, 326 were assessable. The age of assessable patients ranged from 15 to 82 years (median, 48). The overall CR rate was 77%: 72% in the BHAC group and 81% in the cytarabine group, and there was a significant difference between the two groups (P = .035, chi 2 test). The predicted 55-month EFS rate of all patients was 30%: 23% in the BHAC group and 35% in the cytarabine group, with a significant difference between groups (P = .0253). The predicted 55-month DFS rate of all CR patients was 38% and that of CR patients less than 50 years of age was 47%. There was no significant difference in DFS between the ubenimex group and the group that did not receive ubenimex. CONCLUSION: Analyses of our clinical trial showed that the use of BHAC in remission-induction therapy and in consolidation therapy resulted in poorer CR and EFS rates in adult AML patients compared with the use of cytarabine at the doses and schedules tested. Immunotherapy with ubenimex after the end of all chemotherapy did not improve DFS.

Significance of glutathione-dependent antioxidant system in diabetes-induced embryonic malformations.

Hyperglycemia-induced embryonic malformations may be due to an increase in radical formation and depletion of intracellular glutathione (GSH) in embryonic tissues. In the past, we have investigated the role of the glutathione-dependent antioxidant system and GSH on diabetes-related embryonic malformations. Embryos from streptozotocin-induced diabetic rats on gestational day 11 showed a significantly higher frequency of embryonic malformations (neural lesions 21.5 vs. 2.8%, P<0.001; nonneural lesions 47.4 vs. 6.4%, P<0.001) and growth retardation than those of normal mothers. The formation of intracellular reactive oxygen species (ROS), estimated by flow cytometry, was increased in isolated embryonic cells of diabetic rats on gestational day 11. The concentration of intracellular GSH in embryonic tissues of diabetic pregnant rats on day 11 was significantly lower than that of normal rats. The activity of y-glutamylcysteine synthetase (gamma-GCS), the rate-limiting GSH synthesizing enzyme, in embryos of diabetic rats was significantly low, associated with reduced expression of gamma-GCS mRNA. Administration of buthionine sulfoxamine (BSO), a specific inhibitor of gamma-GCS, to diabetic rats during the period of maximal teratogenic susceptibility (days 6-11 of gestation) reduced GSH by 46.7% and increased the frequency of neural lesions (62.1 vs. 21.5%, P<0.01) and nonneural lesions (79.3 vs. 47.4%, P<0.01). Administration of GSH ester to diabetic rats restored GSH concentration in the embryos and reduced the formation of ROS, leading to normalization of neural lesions (1.9 vs. 21.5%) and improvement in nonneural lesions (26.7 vs. 47.4%) and growth retardation. Administration of insulin in another group of pregnant rats during the same period resulted in complete normalization of neural lesions (4.3 vs. 21.5%), nonneural lesions (4.3 vs. 47.4%), and growth retardation with the restoration of GSH contents. Our results indicate that GSH depletion and impaired responsiveness of GSH-synthesizing enzyme to oxidative stress during organogenesis may have important roles in the development of embryonic malformations in diabetes.

Myeloablative allogeneic hematopoietic stem cell transplantation for Philadelphia chromosome-positive acute lymphoblastic leukemia in adults: significant roles of total body irradiation and chronic graft-versus-host disease.

Disease-free survival in Philadelphia chromosome-positive ALL (Ph + ALL) is very poor, and allogeneic hematopoietic stem cell transplantation (allo-HSCT) is currently considered the only procedure with curative potential. To identify factors affecting transplant outcome, we analyzed the data from 197 Ph + ALL patients aged 16 years or older who had undergone allo-HSCT. The 5-year survival rates were 34% for patients in first complete remission (CR), 21% for those in second or subsequent CR, and 9% for those with active disease (P < 0.0001). Multivariate analysis showed four pre-transplant factors as significantly associated with better survival: younger age, CR at the time of transplantation, conditioning with total body irradiation, and HLA-identical sibling donor (P < 0.0001, P < 0.0001, P = 0.0301, P = 0.0412, respectively). Severe acute GVHD increased the risk of treatment-related mortality (TRM) without diminishing the risk of relapse, whereas chronic GVHD reduced the risk of relapse without increasing the risk of TRM. Thus, patients who developed extensive chronic GVHD had better survivals (P = 0.0217), and those who developed grade III-IV acute GVHD had worse survivals (P = 0.0023) than did the others.

Comparison between reduced intensity and conventional myeloablative allogeneic stem-cell transplantation in patients with hematologic malignancies aged between 50 and 59 years.

To evaluate the efficacy of reduced-intensity stem-cell transplantation (RIST), we retrospectively compared outcomes of 207 consecutive Japanese patients aged between 50 and 59 years with hematologic malignancies who received RIST (n=70) and conventional stem-cell transplantation (CST) (n=137). CST recipients received total body irradiation (TBI)-based or busulfan/cyclophosphamide-based regimens. RIST regimens were purine analog-based (n=67), 2 Gy TBI-based (n=2), and others (n=1). Most CST recipients (129/137) received calcineurin inhibitors and methotrexate as graft-versus-host (GVHD) prophylaxis, while 32 RIST recipients received cyclosporin. In all, 23 CST and five RIST recipients died without disease progression within 100 days of transplant. Grade II to IV acute GVHD occurred in 56 CST and 38 RIST recipients. There was no significant difference in overall survival (OS) and progression-free survival between CST and RIST. On multivariate analysis on OS, five variables were significant: preparative regimens (CST vs RIST) (hazard ratio=1.92, 95% confidence interval, 1.25-2.97; P=0.003), performance status (2-4 vs 0-1) (2.50, 1.51-4.16; P<0.001), risk of underlying diseases (1.85, 1.21-2.83; P=0.004), acute GVHD (2.57, 1.72-3.84; P<0.001), and CML (0.38, 0.21-0.69; P=0.002). We should be careful in interpreting results of this small-sized retrospective study; however, reduced regimen-related toxicity might contribute to better survival in RIST. The low relapse rates following RIST suggest a strong antitumor activity through allogeneic immunity.

Effect of graft-versus-host disease on the outcome of bone marrow transplantation from an HLA-identical sibling donor using GVHD prophylaxis with cyclosporin A and methotrexate.

The effect of graft-versus-host disease (GVHD) on relapse incidence and survival has been analyzed in several studies, but previous studies included heterogeneous patients. Therefore, we analyzed the data of 2114 patients who received unmanipulated bone marrow graft from an HLA-identical sibling donor with a GVHD prophylaxis using cyclosporin A and methotrexate. Among the 1843 patients who survived without relapse at 60 days after transplantation, 435 (24%) developed grade II-IV acute GVHD. Among the 1566 patients who survived without relapse at 150 days after transplantation, 705 (47%) developed chronic GVHD. The incidence of relapse was significantly lower in patients who developed acute or chronic GVHD, but disease-free survival (DFS) was significantly inferior in patients who developed acute GVHD. A benefit of 'mild' GVHD was only seen in high-risk patients who developed grade I acute GVHD. The strongest association between GVHD and a decreased incidence of relapse was observed in patients with standard-risk acute myelogenous leukemia/myelodysplastic syndrome. In conclusion, the therapeutic window between decreased relapse and increased transplant-related mortality due to the development of GVHD appeared to be very narrow.

Morphological subtyping of acute myeloid leukemia with maturation (AML-M2): homogeneous pink-colored cytoplasm of mature neutrophils is most characteristic of AML-M2 with t(8;21).

Morphologic and cytochemical features of 30 acute myeloid leukemia subtype M2 (AML-M2) patients with t(8;21) were compared with those of 50 AML-M2 patients without t(8;21). It was disclosed that irregular nuclear shape, Auer bodies, and at least 90% myeloperoxidase positivity in blast cells, and pseudo-Pelger-Huët anomaly of the nuclei and homogeneous pink-colored cytoplasm of mature neutrophils were observed in 90-100% of the t(8;21)+ patients. The percentages of patients showing these features were significantly (P < 0.01) lower in the t(8;21)- group. Among these morphological features, homogeneous pink-colored cytoplasm of mature neutrophils is most characteristic of t(8;21)+ AML-M2, because it was seen in 90% of the t(8;21)+ patients but in only 2% of the t(8;21)- patients. Conversely, pale-colored cytoplasm without any granules in mature neutrophils or dyserythropoietic features was observed in 84% of the t(8;21)- patients, but in none of the t(8;21)+ patients. These data suggest that it is possible to subtype AML-M2 patients morphologically by the recognition of homogeneous pink-colored or pale-colored cytoplasm of mature neutrophils and dyserythropoietic features. Thus, the morphologic subtyping of AML-M2 can be utilized alone or in combination with chromosomal or molecular subtyping for biological and clinical studies of AML with maturation.

Pre-transplant diabetes mellitus is a risk factor for non-relapse mortality, especially infection-related mortality, after allogeneic hematopoietic SCT.

Diabetes mellitus (DM) is a factor in the hematopoietic cell transplantation-comorbidity index. However, the impact of pre-transplant DM on morbidity and cause-specific non-relapse mortality (NRM) remains unclear. We performed a retrospective study with registry data that included a total of 7626 patients who underwent their first allogeneic hematopoietic SCT (HSCT) between 2007 and 2010. The median age was 44 years (range 0-88). Compared with patients without pre-transplant DM (non-DM group, n=7248), patients with pre-transplant DM (DM group, n=378) were older and were more likely to have high-risk disease, a reduced-intensity conditioning regimen and GVHD prophylaxis using tacrolimus. Multivariate analyses showed that pre-transplant DM was associated with increased risks of NRM (hazard ratio (HR)1.46, 95% confidence interval (CI) 1.21-1.76, P<0.01) and infection-related NRM (HR 2.08, 95% CI 1.58-2.73, P<0.01). The presence of pre-transplant DM was associated with an increased risk of overall mortality in a multivariate analysis (HR 1.55, 95% CI 1.35-1.78, P<0.01). In conclusion, pre-transplant DM was a risk factor for NRM, particularly infection-related mortality, after allogeneic HSCT. To improve the clinical outcome in patients with DM, the benefits of strict infection control and appropriate glycemic control should be explored in future trials.

Second allogeneic hematopoietic stem cell transplantation in children with severe aplastic anemia.

The outcome of 55 children with severe aplastic anemia (SAA) who received a second hematopoietic stem cell transplantation (HSCT) was retrospectively analyzed using the registration data of the Japanese Society for Hematopoietic Cell Transplantation. The 5-year overall survival (OS) and failure-free survival (FFS) after the second transplantation were 82.9% (95% confidence interval (CI), 69.7-90.8)) and 81.2% (95% CI, 67.8-89.4), respectively. FFS was significantly better when the interval between the first and second transplantation was >60 days (88.9%; 95% CI, 73.0-95.7) than when it was ⩽60 days (61.4%; 95% CI, 33.3-80.5; P=0.026). All 12 patients who were conditioned with regimens containing fludarabine and melphalan were alive with hematopoietic recovery. These findings justify the recommendation of a second HSCT for children with SAA who have experienced graft failure after first HSCT.

Clinical significance of pretransplant serum ferritin on the outcome of allogeneic hematopoietic SCT: a prospective cohort study by the Kanto Study Group for Cell Therapy.

This prospective study aimed to investigate the influence of pretransplant serum ferritin levels on the outcomes of allogeneic hematopoietic SCT (HSCT). In total, 190 patients with acute leukemia or myelodysplastic syndrome were consecutively enrolled. The patients were divided into two groups: low-ferritin group (<1000 ng/mL) and high-ferritin group (⩾1000 ng/mL). The primary end point was the cumulative incidence of infection within 100 days after HSCT, which was similar between the two groups: bloodstream infection, 35 vs 38%, P=0.65; bacterial infection, 44 vs 41%, P=0.68; and fungal infection, 6 vs 8%, P=0.71. The 1-year adjusted probability of OS of the high-ferritin group was significantly lower than that of the low-ferritin group (76 vs 63%, P=0.017). Using receiver operating characteristic curve, the threshold of pretransplant serum ferritin levels for bloodstream infection was 1400 ng/mL; the threshold for OS, EFS and non-relapse mortality was 1349 ng/mL. In conclusion, pretransplant serum ferritin levels of ⩾1000 ng/mL did not influence the incidence of infection but adversely affected OS after HSCT. A higher threshold of pretransplant serum ferritin levels may predict HSCT outcomes.

Troglitazone ameliorates insulin resistance in patients with Werner's syndrome.

Insulin resistance in Werner's syndrome (WS) is probably due to defective signaling distal to the insulin receptor. To analyze the metabolic effects of troglitazone (TRO) in these patients, we performed frequently sampled iv glucose tolerance tests. Glucose kinetics were analyzed by the minimal model. Five patients with WS (mean age, 41.2 yr; body mass index, 17.0 kg/m2) were treated with TRO (400 mg/day) for 4 weeks. Each subject underwent a 75-g OGTT and frequently sampled iv glucose tolerance tests. Treatment reduced the area under the curve of glucose and insulin in the OGTT by 26% and 43%, respectively. Glucose tolerance, as manifested by the glucose disappearance rate improved significantly (1.36 +/- 0.16 to 1.94 +/- 0.30%/min; P < 0.05). Although the first phase insulin secretion was unchanged, insulin sensitivity and glucose effectiveness increased significantly [0.47 +/- 0.11 to 1.38 +/- 0.37 x 10(-4) min/pmol.L (P < 0.05) and 1.72 +/- 0.17 to 2.52 +/- 0.24 x 10(-2) min-1 (P < 0.05), respectively]. However, treatment did not change glucose effectiveness at zero insulin. In patients with WS, TRO ameliorates glucose intolerance mediated by increased insulin sensitivity as well as glucose effectiveness, as assessed by minimal model analysis. TRO may modulate the postreceptor signaling component and be a clinically useful regimen for the treatment of patients with the intracellular insulin signaling defect.

High-dose but not low-dose dexamethasone impairs glucose tolerance by inducing compensatory failure of pancreatic beta-cells in normal men.

The diabetogenic effects of glucocorticoids appear to be dose dependent. To determine the effects of different doses of dexamethasone on glucose metabolism, we performed frequently sampled intravenous glucose tolerance tests in 20 healthy young men. Glucose kinetics were analysed by the minimal model. Ten subjects received low-dose dexamethasone (2 mg/day) for 3 days, and the other 10 received high-dose dexamethasone (6 mg/day) for 3 days. The rate of glucose disappearance (KG) did not decrease in the low-dose group (2.46 +/- 0.20 to 2.19 +/- 0.11% min-1, P = 0.35). In contrast, KG in the high-dose group did decrease significantly (2.43 +/- 0.29 to 1.81 +/- 0.11% min-1, P < 0.05). The factor responsible for the decline in KG in the high-dose group was not glucose effectiveness because these values did not change in either group. The insulin sensitivity decreased significantly, by 46% in the low-dose group and 69% in the high-dose group [17.1 +/- 2.7 to 9.2 +/- 1.5 and 18.5 +/- 3.7 to 5.8 +/- 0.9 x 10(-5) min-1 (pmol/L)-1, P < 0.001 and P < 0.01, respectively]. The insulin area (0-20 min) increased significantly, by 104% in the low-dose group and 114% in the high-dose group [3412.6 +/- 609.7 to 6972.7 +/- 1450.1 and 4086.7 +/- 864.5 to 8750.0 +/- 1451.6 (pmol/L) min, P < 0.01 and P < 0.01, respectively]. Insulin sensitivity x insulin area as an estimate of insulin-dependent glucose uptake and insulin's action to suppress hepatic glucose production decreased significantly in the high-dose group (0.588 +/- 0.112 to 0.441 +/- 0.073, P < 0.05), but did not change in the low-dose group (0.436 +/- 0.050 to 0.484 +/- 0.032, P = 0.77). Therefore, the decline in KG in the high-dose group may be associated with the compensatory failure of pancreatic beta-cells against for the insulin resistance.

Oxygen-induced embryopathy and the significance of glutathione-dependent antioxidant system in the rat embryo during early organogenesis.

We investigated the effect of glutathione (GSH)-dependent antioxidant system against hydrogen peroxide (H2O2) formation in oxygen-induced embryopathy. Exposure of rat embryos to a high concentration of oxygen (20%) during early neurulation (day 9 to 10) significantly increased the incidence of neural tube defects compared with control embryos (10% vs 0%, p < 0.01) exposed to a low O2 concentration (5%). The concentration of GSH in 20% O2-exposed embryos was significantly reduced compared with that in control embryos (10.68 +/- 0.72 vs 12.34 +/- 0.65 nmol/mg protein, p < 0.001). The activity of gamma-glutamylcysteine synthetase (gamma-GCS), the rate-limiting GSH synthesizing enzyme increased in 20% O2-exposed embryos (24.83 +/- 0.71 vs 21.00 +/- 0.94 microunits/mg protein). Increased activity of gamma-GCS was associated with increased expression of gamma-GCS mRNA. Substantial increases were also observed in the activities of glutathione peroxidase (GPX) and glutathione S-transferase (GST) in 20% O2-exposed embryos. The formation of intracellular H2O2, measured by flow cytometer using 2',7'-dichlorofluorescein diacetate (DCFH-DA), increased in isolated embryonic cells of 20% O2-exposed embryos. The addition of buthionine sulfoxamine (BSO), a specific inhibitor of gamma-GCS, to culture media exposed to 20% O2 produced a marked decrease in the concentration of GSH in association with a further increase in the incidence of embryonic malformations (24.4% vs. 10%, P < 0.01). The addition of 2.0 mM GSH ester to culture media exposed to 20% O2 prevented the development of embryonic malformations through the restoration of normal GSH contents and reduction of H2O2. Our results demonstrated that oxygen-induced embryonic malformations were induced by increased production of H2O2 in the presence of an immature free radical scavenger system. We suggest that impaired responsiveness of the GSH dependent antioxidant system against oxidative stress plays a crucial role in oxygen-induced embryopathy.