Modulation of intestinal transport of 2,4-dinitrophenyl-S-glutathione, a multidrug resistance-associated protein 2 substrate, by bilirubin treatment in rats

The effect of bilirubin treatment on intestinal transport of 2,4-dinitrophenyl-S-glutathione (DNP-SG), a substrate of multidrug resistance-associated protein 2 (MRP2), after application of 1-chloro-2, 4-dinitrobenzene (CDNB), a precursor of DNP-SG, was examined in rat intestine by the in-vitro everted sac, in-situ re-circulating perfusion, and in-situ loop methods. CDNB was taken up rapidly by jejunum and ileum, and the consequent intestinal efflux of DNP-SG, a glutathione conjugated metabolite of CDNB, was significantly higher in jejunum than in ileum in the in-situ and in-vitro studies. Co-administration of bilirubin (100 microM), as well as probenecid (1 mM) or ciclosporin (100 microM), with CDNB decreased the DNP-SG efflux in jejunum significantly, but not in ileum. The suppression of DNP-SG efflux in jejunum was also observed after intravenous administration of bilirubin (85.5 micromol kg-1), in which plasma bilirubin glucuronide levels were approximately 100 microM. In the in-vitro metabolism study, bilirubin exerted no significant effect on CDNB metabolism in the intestinal S9 fraction (supernatant of 9000 g). These results suggested that the diseased states accompanied with hyperbilirubinaemia might have increased the intestinal absorption, or oral bioavailability, of MRP2 substrates by suppressing MRP2 function at the proximal intestinal region.     

Adrenomedullin causes coronary vasodilation in humans: effects of inhibition of nitric oxide synthesis

Experimental studies have shown that adrenomedullin (AM) causes vasodilation, in part, mediated by endothelium-derived nitric oxide (NO). However, it remains to be clarified how NO is involved in AM-induced coronary vasoreactivity in humans. We examined whether NO contributes to the vasodilatory effects of adrenomedullin on human coronary arteries. In 10 patients with angiographically normal coronary arteries, adrenomedullin (low dose: 1 ng/kg/min; high dose: 10 ng/kg/min) was infused into the left coronary ostium before and after an infusion of N-monomethyl-L-arginine (L-NMMA, 40 micromol/min for 5 min), an NO synthase inhibitor. Coronary diameter and coronary blood flow (CBF) were evaluated by quantitative angiography and Doppler flow velocity measurements. Changes in these parameters in response to adrenomedullin were expressed as percent changes from baseline values. Adrenomedullin at a high dose dilated coronary arteries (3.7+/-0.5%, P<0.001). Adrenomedullin increased the coronary blood flow at both doses (low: 55.7+/-13.9%, P<0.01; high: 48.8+/-9.8%, P<0.001). After the infusion of L-NMMA, adrenomedullin-induced coronary vasodilation and increase in coronary blood flow were attenuated. These findings suggest that adrenomedullin dilates human coronary arteries through an increase in NO production, at least in part.     

The effects of immediate enteral feeding with a formula containing high levels of omega-3 fatty acids in patients after surgery for esophageal cancer

BACKGROUND: We investigated whether supplementation of enteral nutrition (EN) with omega-3 polyunsaturated acids (PUFAs) affected platelet aggregation, coagulation activity, and inflammatory response in the early stages after esophageal cancer surgery. METHODS: Twenty-eight patients with esophageal cancer who underwent the same surgical procedure were selected for this study. All patients received EN, which was started immediately after the operation and was increased to a maximum volume of 1500 ml/day by the third postoperative day (POD). Eleven patients received a conventional EN formula (Ensure Liquid), while the remaining 17 patients received a different formula rich in omega-3 PUFAs (Racol [RAC]). Several markers of coagulation and fibrinolysis were determined in POD 2, while the concentrations of interleukin (IL)-6, IL-8, 6-keto-PGF1alpha and thromboxane B2 were determined on PODs 1, 3, and 5. RESULTS: A total of 27 patients completed the study, 11 in the Ensure Liquid group and 16 in the RAC group. Administration of RAC significantly inhibited the postoperative decrease in platelet count. The level of D-dimer was attenuated significantly in the RAC group. Plasma IL-8 levels were decreased significantly in the RAC group on PODs 1 and 3. The anti-inflammatory effects of omega-3 PUFAs were confirmed by the clinical findings of lower body temperature. The plasma concentration of 6-keto-PFG1alpha also tended to decrease in the RAC group with a significant difference on POD 5. CONCLUSIONS: Early EN with a large amount of omega-3 PUFAs in reduced platelet aggregation, coagulation activity, and cytokine production. All these effects would be expected to be beneficial in patients following esophageal cancer surgery. The clinical significance of the changes in eicosanoid production remains to be established.     

Mid-term results of open aortic valvotomy for infants with critical aortic stenosis: seven-year experience including delayed Ross strategy.

OBJECTIVES: The purpose of this study is to provide short- and mid-term results of open aortic valvotomy (OAV) for patients with critical aortic stenosis (AS). METHODS: Between December 1993 and June 1996, 6 patients with critical AS underwent an OAV in our unit. Their ages and body weights at operation ranged from 1 to 65 days (median age, 9 days) and from 2.4 to 5.7 kg (median weight, 3.3 kg), respectively. Peak pressure gradient and diameter of the aortic valve ranged from 25 to 111 mmHg (mean value, 79 mmHg) and from 4.6 to 7.5 mm (mean diameter, 6.1 mm), respectively. OAV comprised the valvular commissurotomy and excision of the myxomatous nodules with cardiopulmonary bypass. RESULTS: No early or late death occurred. Mean peak pressure gradient across the aortic valve was reduced to 33 mmHg (from 15 to 44 mmHg) with no aortic insufficiency in 2 patients and trivial insufficiency in 4. During the follow-up period of 6 to 9 years, 3 out of 6 patients required no reintervention. The other 3 patients required repeated valvotomy for recurrent stenosis within 0.2 to 1.3 years after the operation. Of these, 2 patients required the Ross procedure at 7 years of age or older, and another at 6 years of age awaits the Ross procedure. CONCLUSION: OAV for critical AS was effective without causing mortality or significant aortic insufficiency. Our current strategy comprising the initial OAV and "delayed Ross procedure" for recurrent stenosis with or without insufficiency is a promising therapeutic option for infants with critical AS.     

Relationship between ABO histo-blood group type and an outbreak of norovirus gastroenteritis among primary and junior high school students: results of questionnaire-based study

Noroviruses are common causative agents of epidemic gastroenteritis in humans. Recent studies showed that human susceptibility to noroviruses was associated with ABO histo-blood group type. It was also observed that various degrees of susceptibility were exhibited by different norovirus strains. In January 2003, an outbreak of acute gastroenteritis including 661 affected primary and junior high school students occurred through lunch bread contaminated with norovirus in Hokkaido, Japan. To clarify the relationship between ABO histo-blood group type and the norovirus infection, we performed a written questionnaire to schoolchildren about the consumption of the bread, onset of symptoms and person-to-person transmission in their household. Questionnaires were returned from 722 schoolchildren (response rate, 65.8%), of whom 55.3% suffered gastroenteritis. As a result of this survey, it was found that schoolchildren with blood group type A (71.1%, 133/187) were more susceptible to the norovirus infection, whereas, schoolchildren with blood group type AB (55.3%, 26/47) were less affected (P (Z0) < 0.025). In addition, the presumptive prevalence rate of person-to-person transmission in each household indicated that schoolchildren with blood group type AB (19.2%, 5/26) had a lower risk of infection than those with blood group type A or O [A : 41.4%, 55/133 O : 39.5%, 49/124 (unknown for one case) ] [P (Z0) < 0.025]. Our findings suggested that persons with blood group type AB were less affected by the norovirus infection in this outbreak.     

Association of Helicobacter pylori infection with systemic inflammation and endothelial dysfunction in healthy male subjects

OBJECTIVES: The goal of the present study was to determine whether seropositivity to Helicobacter pylori (HP), Chlamydia pneumoniae (CP), and cytomegalovirus (CMV) is associated with systemic inflammation and endothelial dysfunction in healthy male subjects. BACKGROUND: Chronic infection with certain bacteria and viruses may play an important role in inflammation as the pathogenesis of atherosclerosis. METHODS: The serum levels of immunoglobulin G antibodies to HP, CP, CMV, high-sensitivity C-reactive protein, soluble intercellular adhesion molecule-1, and soluble vascular cell adhesion molecule-1 were determined in 81 healthy Japanese men (40 +/- 10 years of age). High-frequency ultrasonographic imaging of the brachial artery was used to study endothelium-dependent (flow-mediated vasodilation) and endothelium-independent (nitroglycerin-induced) vasodilation. RESULTS: Prevalences of seropositive antibodies to HP, CP, and CMV were 67.9%, 61.7%, and 56.8%, respectively. Infection with HP, CP, or CMV had no relationship with age, blood pressure, or level of serum glucose, lipid, or soluble vascular cell adhesion molecule-1. The levels of C-reactive protein and soluble intercellular adhesion molecule-1 were significantly higher, and flow-mediated vasodilation was significantly lower in subjects with seropositive antibodies to HP than in subjects with seronegative antibodies to HP. Endothelium-independent vasodilation was similar in both groups. CONCLUSIONS: Chronic infection with HP may be involved in the development of the atherosclerosis via endothelial dysfunction and systemic and vascular inflammation.     

BMK1 is activated in glomeruli of diabetic rats and in mesangial cells by high glucose conditions

BACKGROUND: High glucose causes renal cell injury through various signal transduction pathways, including mitogen-activated protein (MAP) kinases cascades. Big MAP kinase 1 (BMK1), also known as extracellular signal-regulated kinase 5 (ERK5), is a recently identified MAP kinase family member and was reported to be sensitive to osmotic and oxidative stress. However, the role of BMK1 in diabetic nephropathy has not been elucidated yet. METHODS: We investigated whether BMK1 is activated in the glomeruli of Otsuka Long Evans Tokushima Fatty (OLETF) rats, a model of type 2 diabetes mellitus in comparison with the control Long Evans Tokushima Otsuka (LETO) rats. We also examined the effect of high glucose on BMK1 activity in cultured rat mesangial cells. RESULTS: BMK1 and ERK1/2 but not p38 were activated in the glomeruli of OLETF rats, which showed diabetic nephropathy at 52 weeks of age. High glucose, in addition to a high concentration of raffinose, caused rapid and significant activation of BMK1 in rat mesangial cells. MAP kinase/ERK kinase (MEK) inhibitors, U0126 and PD98059, both inhibited BMK1 activation by high glucose in a concentration-dependent manner. Protein kinase C (PKC) inhibition by GF109203X and PKC down-regulation with long-time phorbol myristate acetate (PMA) treatment both inhibited BMK1 and Src kinase activation. Src kinase inhibitors, herbimycin A and PP2, also inhibited high glucose-induced BMK1 activation. PKC inhibitors, Src inhibitors and MEK inhibitors, all inhibited cell proliferation by high glucose. Finally, transfection of dominant-negative MEK5, which is an upstream regulator of BMK1, abolished the BMK1-mediated rat mesangial cell proliferation stimulated by high glucose. CONCLUSION: In the present study, we demonstrated that high glucose activates BMK1 both in vivo and in vitro. It was suggested that high glucose induces PKC- and c-Src-dependent BMK1 activation. It could not be denied that BMK1 activation is induced through an osmotic stress-sensitive mechanism. BMK1-mediated mesangial cell growth may be involved in the pathogenesis of diabetic nephropathy.     

A simple and accurate formula to estimate left hepatic graft volume in living-donor adult liver transplantation

BACKGROUND: In the field of living-donor adult liver transplantation, a small-for-size graft often occurs, particularly when using left-lobe grafts. This is because of the limited volumes associated with left-lobe grafts. The accurate preoperative evaluation of graft volumes is crucial to avoid this complication. The aim of this study is to clarify the usefulness of a new formula to estimate the left-lobe graft volume. METHOD: In 61 left-lobe grafts, a new formula was created with stepwise regression analysis using the following variables: height, weight, the thoracic and abdominal distance from anterior to posterior side (A-P), and distance from left to right side (L-R) of the initial 20 donors. With another 41 donors, the difference between the actual and estimated graft volume using the formula and two- and three-dimensional computed tomography was prospectively evaluated. RESULTS: On the basis of the results of the stepwise regression analysis, a new formula was created as follows: graft volume (ml) = 313.4 + 7.7 x weight (kg)-12.6 x thoracic L-R (cm). The difference between the actual and estimated graft volumes using the formula was significantly better (10.8 +/- 9.5%) than that of the volumetry using two-dimensional computed tomography (16.3 +/- 10.1%) (P < 0.05). CONCLUSIONS: In conclusion, the new formula can estimate the actual graft volume more accurately than conventional volumetry with two-dimensional computed tomography. The formula is useful to estimate the volume of left-lobe graft in living-donor adult liver transplantation.     

Role of Dok-1 and Dok-2 in myeloid homeostasis and suppression of leukemia

Dok-1 and Dok-2 are closely related rasGAP-associated docking proteins expressed preferentially in hematopoietic cells. Although they are phosphorylated upon activation of many protein tyrosine kinases (PTKs), including those coupled with cytokine receptors and oncogenic PTKs like Bcr-Abl, their physiological roles are largely unidentified. Here, we generated mice lacking Dok-1 and/or Dok-2, which included the double-deficient mice succumbed to myeloproliferative disease resembling human chronic myelogenous leukemia (CML) and chronic myelomonocytic leukemia. The double-deficient mice displayed medullary and extramedullary hyperplasia of granulocyte/macrophage progenitors with leukemic potential, and their myeloid cells showed hyperproliferation and hypo-apoptosis upon treatment and deprivation of cytokines, respectively. Consistently, the mutant myeloid cells showed enhanced Erk and Akt activation upon cytokine stimulation. Moreover, loss of Dok-1 and/or Dok-2 induced blastic transformation of chronic phase CML-like disease in mice carrying the bcr-abl gene, a cause of CML. These findings demonstrate that Dok-1 and Dok-2 are key negative regulators of cytokine responses and are essential for myeloid homeostasis and suppression of leukemia.