Effect of climatic elements on Campylobacter colonization in broiler flocks reared in southern Japan from 2008 to 2012.

To demonstrate the effect of climatic elements on Campylobacter colonization in broiler chickens reared in Japan, the correlation between Campylobacter isolated from chickens (191 of 236 flocks, 80.9%) between 2008 and 2012 and climatic elements was analyzed by logistic regression. We divided the rearing process into 13 terms of 5 d each (total: 65 d). Terms were numbered backwards, wherein a 0-term lag was considered as the sampling day plus 4 d before sampling; 1-term lag was the 5-d term before the 0-term lag, and so on, until the 12-term lag. We obtained climatic data tracing back from the 0-term to the 12-term lags. For evaluation in each season, we divided chickens reared during periods of rising temperature (spring, summer) and decreasing temperature (autumn, winter). Air temperature showed a positive correlation with Campylobacter colonization from the 0- to 12-term lags in chickens reared during the period of rising temperature (odds ratio [OR], 1.069 to 1.104), and from the 0- to 4- and 6-term lags (OR, 1.079 to 1.105) in chickens reared during the period of decreasing temperature. The strong positive effect of air temperature on Campylobacter colonization, particularly during the period of rising temperature, may be associated with the effect on the Campylobacter environmental sources and/or vectors. A positive correlation was observed between Campylobacter colonization and humidity when chicken houses were empty and new chicks were introduced (from the 9- to 12-term lags) during the period of decreasing temperature (OR, 1.076 to 1.141). Thus, high humidity would be an important factor causing carry-over of Campylobacter infection during the period of decreasing temperature. We also found that solar radiation increased Campylobacter colonization during the period of decreasing temperature, from the 2- to 8-term lags, except for the 4- and 5-term lags, in Japan. The results of this study demonstrate the effects of air temperature, humidity, and solar radiation on Campylobacter colonization in broiler chickens, and are potentially important for developing strategies to reduce the risk of Campylobacter contamination in broiler chickens.

Low-dose gonadotropin-releasing hormone agonist therapy (draw-back therapy) for successful long-term management of adenomyosis associated with cerebral venous and sinus thrombosis from low-dose oral contraceptive use.

The authors report a case of cerebral venous and sinus thrombosis (CVST) in a patient receiving a low-dose estrogen-progestin combination (oral contraceptives, OCs) for uterine adenomyosis. She was switched to gonadotropin-releasing hormone agonist (GnRHa) draw-back therapy, which was successfully administered long-term. CASE: The patient was a 38-year-old nulligravida with a history of smoking. She presented to this hospital with dysmenorrhea and postmenstrual lower abdominal pain. Adenomyosis was diagnosed using ultrasound and magnetic resonance imaging. She was instructed to stop smoking and was administered low-dose OCs. CVST occurred 18 months later. OC therapy was halted, and only antiplatelet therapy was administered. After six months, her chief complaint symptoms intensified, therefore GnRHa draw-back therapy was administered after obtaining informed consent. No uterine enlargement was observed, and the abdominal pain resolved. During 2.5 years of therapy, her bone density levels remained within normal limits. CVST did not recur and no other thromboses were observed.

Continued widespread dissemination and increased poultry host fitness of Campylobacter jejuni ST-4526 and ST-4253 in Japan.

AIMS: Campylobacter jejuni is a major cause of foodborne gastroenteritis. We previously reported the widespread Camp. jejuni sequence type (ST)-4526 in Japan from 2005 to 2006. This study assesses the potential for this genotype to thrive thereafter. METHODS AND RESULTS: Fifty human Camp. jejuni isolates collected in 2010-2011 in Osaka, Japan, were genotyped by multilocus sequence typing (MLST). This approach identified 22 STs and 11 clonal complexes (CCs), including four novel STs. A comparative analysis to the previous data set showed the predominance of CC-21, in which ST-4526 and ST-4253 represented 39 and 63% in each of the two time frames, indicating their continued widespread presence. These two STs belong to close evolutionary lineages and are also isolated from chicken meat. The superior abilities of ST-4526/ST-4253 representatives to colonize chicken gut were demonstrated by co-infections with ST-21, ST-50 and ST-8 representatives. CONCLUSIONS: Data provide evidence for the continued widespread of ST-4526/ST-4253 among human clinical isolates in Japan. These STs showed adaptive fitness to chicken. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first evidence of the continued thriving of ST-4526/ST-4253 in Japan with their increased in vivo fitness. Our findings suggest that poultry mediates the microevolution of this pathogen, thereby enabling these STs to become widespread.

A case of acquired FXIII deficiency with severe bleeding symptoms.

Acquired factor XIII (FXIII) deficiency due to an autoantibody against FXIII is a very rare, yet potentially life-threatening bleeding disorder. As the standard coagulation tests (prothrombin time and activated partial thromboplastin time) are normal, the specialized tests are required to make an accurate diagnosis. Here, we report a case of acquired FXIII deficiency with severe bleeding symptoms. A 75-year-old man was referred to our hospital because of severe bleeding tendency after a tooth extraction. Laboratory findings showed that routine coagulation studies were normal, but factor XIII (FXIII) activity was low (3%). The presence of FXIII inhibitor was detected with dot blotting studies. Although the bleeding tendency was very severe, it was successfully controlled by infusion of FXIII concentrates combined with immunosuppressive treatment (oral prednisolone). Fibrin cross-linking study showed the significant delay of the γ-chain dimer and α-chain polymer formation. Western blotting revealed the marked decrease in FXIII-A level. The mixing study of FXIII activity measured using amine-incorporation assay showed the incomplete inhibition pattern. There seems to be little agreement as to the treatment strategy of acquired FXIII deficiency. In this patient, the use of FXIII concentrates was very useful in the initial treatment of bleeding symptom. The use of steroids was also effective in increasing FXIII activity without any serious complications.

Prevalence and growth kinetics of Shiga toxin-producing Escherichia coli (STEC) in bovine offal products in Japan.

Recent epidemiological data suggest a link between the consumption of bovine offal products and Shiga toxin-producing Escherichia coli (STEC) infection in Japan. This study thus examined the prevalence of STEC in various types of these foods. PCR screened 229 bovine offal products for the presence of Shiga toxin (stx) gene. Thirty-eight (16·6%) samples were stx positive, of which eight were positive for rfbE(O157) and three were positive for wzy(O26). Four O157 and one O26 STEC isolates were finally obtained from small-intestine and omasum products. Notably, homogenates of bovine intestinal products significantly reduced the extent of growth of O157 in the enrichment process compared to homogenates of beef carcass. As co-incubation of O157 with background microbiota complex from bovine intestinal products in buffered peptone water, in the absence of meat samples, tended to reduce the extent of growth of O157, we reasoned that certain microbiota present in offal products played a role. In support of this, inoculation of generic E. coli from bovine intestinal products into the homogenates significantly reduced the extent of growth of O157 in the homogenates of bovine intestinal and loin-beef products, and this effect was markedly increased when these homogenates were heat-treated prior to inoculation. Together, this report provides first evidence of the prevalence of STEC in a variety of bovine offal products in Japan. The prevalence data herein may be useful for risk assessment of those products as a potential source of human STEC infection beyond the epidemiological background. The growth characteristic of STEC O157 in offal products also indicates the importance of being aware when to test these food products.

Gypsum and organic matter distribution in a mixed construction and demolition waste sorting process and their possible removal from outputs.

With insufficient source separation, construction and demolition (C&D) waste becomes a mixed material that is difficult to recycle. Treatment of mixed C&D waste generates residue that contains gypsum and organic matter and poses a risk of H(2)S formation in landfills. Therefore, removing gypsum and organic matter from the residue is vital. This study investigated the distribution of gypsum and organic matter in a sorting process. Heavy liquid separation was used to determine the density ranges in which gypsum and organic matter were most concentrated. The fine residue that was separated before shredding accounted for 27.9% of the waste mass and contained the greatest quantity of gypsum; therefore, most of the gypsum (52.4%) was distributed in this fraction. When this fine fraction was subjected to heavy liquid separation, 93% of the gypsum was concentrated in the density range of 1.59-2.28, which contained 24% of the total waste mass. Therefore, removing this density range after segregating fine particles should reduce the amount of gypsum sent to landfills. Organic matter tends to float as density increases; nevertheless, separation at 1.0 density could be more efficient.

Antimicrobial resistance of Campylobacter: prevalence and trends in Japan.

Campylobacter is one of the most frequently diagnosed bacterial causes of human gastroenteritis in Japan and throughout the world. Resistance to quinolones in Campylobacter jejuni and C. coli isolated from humans has emerged in many countries during the past 15 years because fluoroquinolones are the drug of choice for the treatment of suspected bacterial gastroenteritis. Food contaminated with Campylobacter is the usual source of human infection; therefore, the presence of antimicrobial resistance strains in the food chain has raised concerns that the treatment of human infections will be compromised. The use of antimicrobial agents for food animals and in veterinary medicine is suspected to be correlated with an increase in quinolone-resistant strains of Campylobacter in food animals, especially in poultry products. In contrast to macrolide resistance in C. jejuni and C. coli isolated from humans showing a stable low rate, resistant Campylobacter spp. to quinolones have emerged in Japan. The paper summarizes food-borne Campylobacter infection in Japan, and the prevalence and trends of antimicrobial resistance of Campylobacter from the authors' data and other Japanese papers which reported the antimicrobial resistance of Campylobacter.

Identification and analysis of the osmotolerance associated genes in Listeria monocytogenes.

Listeria monocytogenes, the causative agent of listeriosis, has strong osmotolerance and is able to grow in severe circumstances. Many studies of the mechanisms of listerial osmotolerance have been performed. However, there is much which remains unknown. In previous studies we constructed two kinds of mutant in L. monocytogenes EGD strain to analyse the mechanisms of osmotolerance in L. monocytogenes by molecular genetic methods. In this paper, we summarized the genetical studies of osmotolerance in this bacterium by many researchers and ourselves. First, a transposon-insertional mutant strain was constructed that showed reduced growth in high osmotic agar compared with the parental strain. The results of cloning and sequencing analysis showed that the rel gene, which encodes guanosine tetra- and pentaphosphate synthesis and hydrolysis protein, is involved in osmotolerance in L. monocytogenes. Next, the expression levels of five sigma factor coding genes in L. monocytogenes were examined using real-time polymerase chain reaction (PCR) and it was found that the rpoN gene (the alternative sigma factor RpoN (sigma54)-encoding gene) was activated under high osmotic conditions. A deletion mutant of rpoN was constructed and its response to osmotic stress was analysed. In minimal medium with NaCl and carnitine, an osmoprotectant, the mutant showed deficient growth to that of the parental strain when the starting optical density was high, though the expression level of carnitine transporter operon, opuC, and the rate of carnitine uptake in the mutant was similar to that of EGD. These results suggest that the rpoN mutant may need larger amounts of carnitine which might be needed for its growth under high osmolarity. Through the analysis of these mutants, new insights have been obtained into osmotolerance in L. monocytogenes.

Immature platelet fraction for prediction of platelet engraftment after allogeneic stem cell transplantation.

Platelet regeneration represents an important and separate element in the engraftment process for allogeneic stem cell transplantation. Fully automated flow cytometry using blood cell counters now allows reliable quantification of reticulated platelets, expressed as the immature platelet fraction (IPF). We studied the kinetics of IPF in six patients grafted with allogeneic peripheral blood stem cell transplantation (PBSCT), 12 patients with bone marrow transplantation (BMT) and seven patients with cord blood transplantation (CBT). Preconditioning therapy caused an immediate and rapid fall in tri-lineage hematopoiesis. IPF rose transiently above 3% after a mean duration of 11 days post-PBSCT, 18 days post-BMT and 19 days post-CBT. This was 1, 4 and 13 days earlier than platelet engraftment, respectively. A linear correlation model showed a close association between the rise of IPF and tri-lineage engraftment after transplantation. IPF counting may thus provide an accessible measure of thrombopoietic activity, leading to early evaluation of marrow function and allowing monitoring of platelet regeneration.

Safety and efficacy of foscarnet for preemptive therapy against cytomegalovirus reactivation after unrelated cord blood transplantation.

In association with the increased use of unrelated cord blood transplantation (UCBT) in adults, numerous patients have developed cytomegalovirus (CMV) reactivation concomitant with cytopenia. Although foscarnet appears to offer similar efficacy and higher safety as a preemptive therapy against CMV infection than ganciclovir, little is known about the usefulness of foscarnet in such patients. Foscarnet was administered as preemptive therapy against CMV antigenemia in 10 UCBT recipients who were unable to receive ganciclovir due to cytopenia or poor response to ganciclovir. Fatal CMV disease developed in one patient, whereas CMV antigenemia resolved without progression to CMV disease in the remaining nine patients. Foscarnet was well tolerated without serious hematotoxicity and was not discontinued due to adverse events in any patient. Foscarnet represents a safe and effective agent for preemptive therapy against CMV infection and may offer a feasible alternative to ganciclovir in UCBT recipients.

Efficacy and safety of recombinant human soluble thrombomodulin (ART-123) in disseminated intravascular coagulation: results of a phase III, randomized, double-blind clinical trial.

BACKGROUND: Soluble thrombomodulin is a promising therapeutic natural anticoagulant that is comparable to antithrombin, tissue factor pathway inhibitor and activated protein C. OBJECTIVES: We conducted a multicenter, double-blind, randomized, parallel-group trial to compare the efficacy and safety of recombinant human soluble thrombomodulin (ART-123) to those of low-dose heparin for the treatment of disseminated intravascular coagulation (DIC) associated with hematologic malignancy or infection. METHODS: DIC patients (n = 234) were assigned to receive ART-123 (0.06 mg kg(-1) for 30 min, once daily) or heparin sodium (8 U kg(-1) h(-1) for 24 h) for 6 days, using a double-dummy method. The primary efficacy endpoint was DIC resolution rate. The secondary endpoints included clinical course of bleeding symptoms and mortality rate at 28 days. RESULTS: DIC was resolved in 66.1% of the ART-123 group, as compared with 49.9% of the heparin group [difference 16.2%; 95% confidence interval (CI) 3.3-29.1]. Patients in the ART-123 group also showed more marked improvement in clinical course of bleeding symptoms (P = 0.0271). The incidence of bleeding-related adverse events up to 7 days after the start of infusion was lower in the ART-123 group than in the heparin group (43.1% vs. 56.5%, P = 0.0487). CONCLUSIONS: When compared with heparin therapy, ART-123 therapy more significantly improves DIC and alleviates bleeding symptoms in DIC patients.

Reduced-intensity unrelated cord blood transplantation for treatment of metastatic renal cell carcinoma: first evidence of cord-blood-versus-solid-tumor effect.

We report a 69-year-old man with cytokine-resistant metastatic renal cell carcinoma treated with reduced-intensity unrelated cord blood transplantation. The patient achieved durable donor engraftment with minimal graft-versus-host disease. The patient showed regression of metastatic disease, providing the first evidence of a graft-versus-tumor effect on a solid tumor resulting from cord blood graft.

Resuscitation of the viable but non-culturable state of Salmonella enterica serovar Oranienburg by recombinant resuscitation-promoting factor derived from Salmonella Typhimurium strain LT2.

A gene encoding the resuscitation-promoting factor (Rpf) from Salmonella Typhimurium LT2 was cloned and characterized. The amino acid sequence encoded by S. Typhimurium LT2 rpf gene shares 24.2% homology with Micrococcus luteus Rpf, which is secreted by growing cells, and required to resuscitate from viable but non-culturable (VNC) state. The S. Typhimurium LT2 rpf gene is 696 bp long, and shared a conserved segment with Salmonella enterica serovar Oranienburg (99.4%). Recombinant Rpf (rRpf) proteins of S. Typhimurium LT2 after expression in E. coli BL21 harboring the pET15-b plasmid was approximately 25 kDa. Since S. Oranienburg cells are relatively quick to enter the VNC state just after incubating in the presence of 7% NaCl at 37 degrees C for 3 days, we evaluated the biological effect of rRpf by using S. Oranienburg VNC cells. The rRpf not only promoted proliferation but also induced resuscitation of VNC cells to the culturable state in a dose-dependent manner. Therefore, rRpf may be useful for detection of bacterial contaminants present in the VNC form in food samples and the environment.

Selective inducible nitric oxide synthase inhibition attenuates organ dysfunction and elevated endothelin levels in LPS-induced DIC model rats.

We examined the role of nitric oxide (NO) produced by an inducible isoform of NO synthase (iNOS) using N[6]-(iminoethyl)-lysine (L-NIL), a selective iNOS inhibitor, in the rat model of lipopolysaccharide (LPS)-induced disseminated intravascular coagulation (DIC) and investigated changes in organ function, plasma levels of NOX (metabolites of NO) and endothelin. We induced experimental DIC by the sustained infusion of 30 mg kg(-1) LPS for 4 h via the tail vein. We then investigated the effect of L-NIL (6 mg kg(-1), from - 0.5 to 4 h) on LPS-induced DIC. Blood was withdrawn at 4 and 8 h, and all four groups (LPS with or without L-NIL at 4 and 8 h) consisted of eight rats. Three of the animals in the 8-h LPS group died, and we examined blood samples from five rats in this group. None of the other rats died. The LPS-induced elevation of creatinine, alanine aminotransferase, glomerular fibrin deposition and plasminogen activator inhibitor was significantly suppressed by L-NIL coadministration, although L-NIL did not affect the platelet count, fibrinogen concentration or the level of thrombin-antithrombin complex. Moreover, plasma levels of the D-dimer that reflect the lysis of cross-linked fibrin were significantly increased by L-NIL coadministration in the LPS-induced DIC model. Plasma levels of NOX and endothelin were obviously increased by LPS infusion. However, both levels were significantly suppressed in the LPS + L-NIL group, when compared with the LPS group. Although mean arterial pressure (MAP) was significantly decreased between 2 and 8 h compared with the control in the LPS group, this depression was significantly attenuated in the LPS + L-NIL group. Our results suggest that NO induced by iNOS contributes to hypotension (depressed MAP), the progression of hepatic and renal dysfunction, microthrombus deposition and elevated endothelin levels in the rat model of LPS-induced DIC.

Expansion and activation of minor histocompatibility antigen HY-specific T cells associated with graft-versus-leukemia response.

The immune system of females is capable of recognizing and reacting against the male-specific minor histocompatibility antigen (mHA), HY. Thus, cytotoxic T-lymphocytes (CTLs) recognizing this antigen may be useful in eradicating leukemic cells of a male patient if they can be generated in vivo or in vitro from a human leukocyte antigen (HLA)-identical female donor. The HLA-A*0201-restricted HY antigen, FIDSYICQV, is a male-specific mHA. Using HLA-A2/HY peptide tetrameric complexes, we reveal a close association between the emergence of HY peptide-specific CD8(+) T cells in peripheral blood and molecular remission of relapsed BCR/ABL(+) chronic myelogenous leukemia in lymphoid blast crisis in a patient who underwent female-to-male transplantation. Assessment of intracellular cytokine levels identified T cells that produce interferon-gamma in response to the HY peptide during the presence of HY tetramer-positive T cells. These results indicate that transplant with allogeneic HY-specific CTLs has therapeutic potential for relapsed leukemia, and that expansion of such T cells may be involved in the development of a graft-versus-leukemia response against lymphoblastic leukemia cells.

Effect of interferon alpha and cell cycle progression on translation mediated by the hepatitis C virus 5' untranslated region: a study using a transgenic mouse model.

The effect of interferon alpha (IFN alpha) and the progression of the cell cycle on translation mediated by the 5' untranslated region (5'UTR) of hepatitis C virus (HCV) was evaluated in a transgenic mouse model containing the beta-galactosidase (beta-gal) gene under the control of the mouse albumin promoter and HCV 5'UTR. The transgene was exclusively expressed in the liver and specifically in hepatocytes around the periportal area. IFN alpha significantly suppressed the expression of both the beta-gal gene product and its enzymatic activity at 6 h after the treatment of the mice. The mRNA level of the transgene and endogenous albumin gene expression were not affected, so this suppression was considered to be specific to 5'UTR-directed translation. Phosphorylation of the Stat1 protein was observed in the liver extract 20 min after the treatment, thus confirming a specific known effect of IFN alpha in vivo. We suggest that suppression of 5'UTR-directed translation may be one of the mechanisms whereby IFN alpha exerts its anti-viral activity. We further investigated whether the restriction of 5'UTR-directed translation in periportal hepatocytes may be explained by the proliferative state of the cell. Transgene expression was slightly enhanced in the liver 48 h after partial hepatectomy when a substantial number of hepatocytes entered cell cycle progression. However, 5'UTR-directed translation could not be detected in hepatocellular carcinoma lesions in transgenic mice that were induced to develop such tumours. We suggest that the state of differentiation of the cell, and not its proliferative capacity, is important for supporting HCV expression. This animal model may be a useful tool to dissect the control of HCV expression and to search for ways to block viral replication.

Anti-IgM-induced down-regulation of nuclear Thy28 protein expression in Ramos B lymphoma cells.

We recently cloned mouse Thy28 cDNA (mThy28), which is highly conserved among vertebrates and plants. The mThy28 mRNA is highly expressed in testis, liver, kidney, brain, with moderate expression in thymus, spleen, and heart. In the present study, characteristics of mouse Thy28 protein expression were examined using rabbit anti-mThy28 polyclonal antibody (Ab). Levels of mThy28 protein expression were highest in testis, with moderate expression in liver, spleen, and thymus. The Thy28 protein was mainly located in the nucleus, which was revealed by immunofluorescence microscopy and Western blotting using anti-mThy28 Ab, and transient expression of the mThy28/EGFP fusion gene. Engagement of membrane immunoglobulin with anti-IgM induced down-regulation of human Thy28 expression at both mRNA and protein levels, accompanied by induction of apoptosis in Ramos B lymphoma cells. Expression of protein and mRNA and induction of apoptosis were evaluated by flow cytometry/Western blotting, reverse transcription-polymerase chain reaction, and propidium iodide staining, respectively. Anti-IgM also down-regulated the promoter activity of the mThy28 gene, as demonstrated by luciferase assay. Thus, the anti-IgM-induced down-regulation of the nuclear Thy28 expression appears to correlate with the induction of apoptosis in Ramos B lymphoma cells.

Association between K469E allele of intercellular adhesion molecule 1 gene and inflammatory bowel disease in a Japanese population.

BACKGROUND AND AIMS: The genetic contribution to inflammatory bowel disease (IBD) is under investigation. Recent evidence indicates a significant linkage between a locus on chromosome 19p13 and IBD. We investigated the association between an intercellular adhesion molecule 1 gene (ICAM-1) polymorphism located on chromosome 19p13 and IBD in a Japanese population. METHODS: We compared 207 Japanese patients who had IBD (79 with Crohn's disease (CD); 128 with ulcerative colitis (UC)) with 103 unrelated Japanese controls. We determined R241G and K469E polymorphisms of the ICAM-1 gene using polymerase chain reaction (PCR) techniques. RESULTS: Both frequency and carriage rate of the K469 allele were significantly higher in IBD patients than in controls (allelic frequency, p(c)=0.0026; carriage rate, p(c)=0.0034; odds ratio 2.59; 95% confidence interval 1.42-4.68). Furthermore, the frequency of the K469 allele was significantly increased in both CD and UC. Subgroup analysis demonstrated that both K469 allelic frequency and K469 carriage rate were significantly higher in patients with the small bowel and colon type of CD and entire colitis compared with healthy controls. CONCLUSIONS: We identified an overall association between IBD and ICAM-1 K469 in a Japanese population. Further studies of this chromosome region are required to elucidate the gene responsible for IBD.

Maternal plasma adenosine and endothelin-1 levels in twin gestation complicated by preeclampsia.

The aim of this study was to evaluate the relationship between the vascular resistance in uterine arteries and the maternal release of adenosine and endothelin-1 in twin gestations with and without preeclampsia. Uterine artery Doppler velocimetry and maternal arterial blood sampling were performed in 14 women with normal singleton gestation, nine women with singleton gestation with preeclampsia, eight women with dichorionic twin gestation without preeclampsia and six women with dichorionic twin gestation with preeclampsia at 28-34 weeks' gestation. In normal singleton gestations, the average maternal uterine arteries pulsatility index (PI), plasma adenosine and endothelin-1 levels were 0.64+/-0.07, 0.34+/-0.11 micromol/l and 1.29+/-0.31 pg/ml, respectively. In preeclamptic singleton gestations, increased vascular resistance in the uterine arteries (PI: 0.85+/-0.14, P<0.05) and the elevation of maternal arterial plasma adenosine (0.48+/-0.14 micromol/l, P<0.05) and endothelin-1 levels (1.91+/-0.55 pg/ml, P<0.05) were observed. In the normal twin gestation group, the average maternal vascular resistance of the uterine arteries (PI: 0.55+/-0.09) was lower than that in the normal singleton gestation group, while the average plasma adenosine levels (0.47+/-0.12 micromol/l) were higher than that in normal singleton gestation. On the other hand, significant increased plasma endothelin-1 concentrations (1.87+/-0.42 pg/ml) were observed in the preeclamptic twin gestation groups without changes in plasma adenosine levels or vascular resistance of uterine arteries. Our results indicate the presence of different mechanisms for the pathogenesis of preeclampsia between twin and singleton gestations.