Yutaka Fujise

The beneficial effect of a prostaglandin I2 analog on ischemic rat liver.

This study was undertaken to determine whether or not prostaglandin I2 (PGI2) analog pretreatment could successfully preserve organ viability after warm hepatic ischemia in rats. Although 120-min ischemia of the liver did not permit survival in rats administered normal saline solution (NS group) before warm ischemia, the survival rate of PGI2 analogue (500 ng/kg/min)—treated rats (PG group) significantly improved to 57% (P<0.05). Recirculation following 120-min hepatic ischemia in the NS group resulted in no improvement of B-phosphorus of the ATP (B-ATP)/inorganic phosphate (Pi) ratio measured by 31P nuclear magnetic resonance, a marked increase in the serum asparate aminotransferase (SAST) level, and an increase in the malondialdehyde (MDA) level in liver tissue. In the PG group, the B-ATP/Pi ratio was significantly improved (P<0.05), the elevation in SAST was also markedly suppressed (P<0.05), and the MDA level of the liver was lowered more than that in the NS group. Severe congestion and extensive vacuolization of hepatocytes from the peripheral to the midzonal areas were histologically exhibited with single-cell necrosis in the NS group. There were fewer histological alterations of the liver and these coincided with the changes in other parameters in the PG group. Our results indicate that PGI2 analog reduces warm ischemic injury of the liver and provides greater protection for organs to be transplanted.

Dexamethasone attenuates neutrophil infiltration in the rat kidney in ischemia/reperfusion injury: the possible role of nitroxyl.

Neutrophil infiltration to the tissue, which is one of the important pathogenetic factors in ischemia/reperfusion injury, can be inhibited by glucocorticoids. The purpose of the present study was to clarify the mechanisms by which glucocorticoids inhibit neutrophil infiltration in renal ischemia/reperfusion injury in rats. Pretreatment with dexamethasone significantly attenuated the enhanced neutrophil infiltration and expression of intercellular adhesion molecule-1 induced by renal ischemia/reperfusion. Treatment with nitroxyl anion releaser known as Angelis salt abolished the beneficial effect of dexamethasone in renal ischemia/reperfusion. Renal dysfunction and tubular damage induced by renal ischemia/reperfusion were not ameliorated by pretreatment with dexamthasone. These results indicate that the attenuation by dexamethasone of neutrophil infiltration and intercellular adhesion molecule-1 expression during renal ischemia/reperfusion may be mediated by the suppressed production of nitroxyl anion. Thus, neutrophil infiltration in renal ischemia/reperfusion injury may be mediated, at least in part, by the enhanced production of nitroxyl anion.

Tryptophan glycoconjugate as a novel marker of renal function

PURPOSE Neither serum creatinine concentration nor creatinine clearance assess renal function accurately. Serum creatinine concentration is affected by muscle mass, and the creatinine clearance overestimates the glomerular filtration rate because of tubular secretion of creatinine. The present study was designed to determine whether serum concentrations of 2-(alpha-mannopyranosyl)-L-tryptophan (MPT), a tryptophan glycoconjugate, can be used as a marker of renal function. METHODS Clearances of MPT and of inulin were compared in normal rats and in rats with cisplatin-induced acute renal failure. We also compared the clearances of MPT and of creatinine with inulin clearance in 25 patients with chronic renal disease. Serum concentrations of MPT and creatinine as a function of MPT clearance were determined in 108 patients with chronic renal disease. RESULTS There was strong linear correlation between clearances of MPT and inulin in rats (r = 0.97) and humans (r = 0.87), indicating that renal handling of MPT is similar to that of inulin. In humans, linear regression analyses indicated that MPT was a better indicator of inulin clearance than was creatinine clearance. At the same level of renal function, serum creatinine concentrations tended to be lower in patients with less muscle mass (as indicated by a urinary creatinine excretion <1,000 mg in 24 hours) than in those who excreted >1,000 mg in 24 hours, whereas serum MPT concentrations were not affected by creatinine excretion. CONCLUSION MPT clearance can replace inulin clearance in the clinical setting. The serum MPT concentration is an accurate measure of renal function even in patients with diminished muscle mass, and thus is a better indicator of renal function than is the serum creatinine concentration.

Macroring contraction methodology : 3. Total syntheses of costunolide and haageanolide using transannular [2,3]-wittig rearrangement of 13-membered diallylic ethers as key reaction

Abstract A new route to construct the carbon skeleton of germacrane sesquiterpenes is described wherein the 13-membered diallylic ethers 12 and 41 , prepared by intramolecular O-alkylation of the bromo alcohol and C-alkylation of the cyanohydrin ether respectively, undergo [2,3]-Wittig rearrangement to give the ten-membered carbocycles. Diastereoselectivity in [2,3]-Wittig rearrangement is discussed based on the MM2 transition structure model using the ab-initio calculations.

Liposomal photofrin enhances therapeutic efficacy of photodynamic therapy against the human gastric cancer.

Photodynamic therapy (PDT) has been established as a potent and less invasive treatment for gastrointestinal tumors. The aim of the present study was to investigate whether or not liposomalization of the photosensitizer enhanced the therapeutic efficacy of PDT. Photofrin (PF) was entrapped in multilammelar liposomes. Mice implanted with a human gastric cancer xenograft, were divided into a PF group and a liposomal photofrin (LPF) group and intravenously administered 10 mg/kg of PF or LPF (as a dose of PF), respectively. At 8 h after injection PF level in tumor tissue in the LPF group was significantly higher level by 2.4-fold of that in the PF group, whereas the PF levels in the skin were almost equal. Irradiation was performed with the excimer dye laser at 150 mW/cm(2), total dose 40 J, at 8 h after PF or LPF administration. The results revealed that the volume of necrotic tumor tissue was significantly higher in the LPF group than in the PF group. The apoptotic index of the tumor was also significantly higher in the LPF group. In conclusion, the liposomalization of the photosensitizer increased its tumor accumulation, with a resulting enhancement of the therapeutic effect of PDT.

Macromolecular surfactant as a pseudo-stationary phase in micellar electrokinetic capillary chromatography

We examined polymers of sodium 11-acrylamidoundecanoate [poly(Na 11-AAU)] with a very high molecular mass (>10(6)) for their potential use as a pseudo-stationary phase in micellar electrokinetic capillary chromatography (MEKC). Size-exclusion chromatography and capillary electrophoresis studies reveal that the polymers are highly charged, and have a densely packed chain structure. For aromatic compounds, the polymeric surfactant showed significantly different selectivity than sodium dodecyl sulfate (SDS). It was suggested that one molecule of poly(Na 11-AAU) forms one micelle. The structural stability of this pseudo-stationary phase permitted its use with relatively high percentages of organic modifiers in the buffer medium, allowing the separation of highly hydrophobic compounds which are difficult to analyze by conventional MEKC with SDS.

Hemodilution with liposome-encapsulated low-oxygen-affinity hemoglobin facilitates rapid recovery from ischemic acidosis after cerebral ischemia in rats.

Liposome-encapsulated hemoglobin (LipoHb) with low oxygen affinity (P50 = 40–50 mmHg) has been developed. The purpose of this study was to evaluate the effects of the LipoHb on incomplete cerebral ischemia. Wistar rats were randomly assigned to one of the following three groups: (A) exchange transfusion with LipoHb solution (Hb = 6 g/dl) (LipoHb, n = 7), (B) exchange transfusion with rat red blood cell (RBC) solution (Hb = 6 g/dl) (RBC, n = 7), (C) no exchange transfusion (control, n = 7). Forebrain ischemia was induced for 9 min by bilateral carotid artery occlusion combined with a decrease in the mean arterial pressure (MAP) to 40 mmHg. 31P-magnetic resonance spectroscopy was performed during ischemia and 60 min of reperfusion. After exchange transfusion, the MAP increased in the LipoHb group and decreased in the RBC group (LipoHb versus RBC; P = 0.0028). During ischemia, intracellular pH (pHi) rapidly decreased in all groups; after reperfusion, the pHi recovery to preischemic levels was more rapid in the LipoHb group than in the RBC group (P < 0.05). Phosphocreatine and β-adenosine triphosphate decreased during ischemia and returned to the preischemic level in all groups following reperfusion. Inorganic phosphate (Pi) increased during ischemia and decreased to the normal value after reperfusion. The LipoHb group had a smaller production of Pi than the other two groups and demonstrated a rapid normalization, although the differences were not significant. Hemodilution with liposome-encapsulated low-oxygen-affinity hemoglobin facilitates rapid pHi recovery from incomplete forebrain ischemia in the rat.

The roles of platelet-activating factor and endothelin-1 in renal damage after total hepatic ischemia and reperfusion.

BACKGROUND This study was designed to verify the involvement of platelet-activating factor (PAF) in renal damage associated with hepatic ischemia and reperfusion (HIR) injury through the release of endothelin (ET)-1 and to determine the modulating effect of a specific PAF receptor antagonist on these insults in rats. METHODS Male rats pretreated with either normal saline as a vehicle (NS group) or intravenous TCV-309, a PAF receptor antagonist (TCV group), were subjected to 120 min of total hepatic ischemia under an extracorporeal portosystemic shunt. Plasma aspartate transaminase, creatinine, blood urea nitrogen, and ET-1 levels and the relative renal wet weight were determined under nonischemic conditions and at 1, 3, and 6 hr of reperfusion after hepatic ischemia. Changes in mean arterial blood pressure and renal tissue blood flow measurements in the kidney were determined throughout the experiment. RESULTS Increased plasma aspartate transaminase, creatinine, blood urea nitrogen, and ET-1 levels and the relative renal wet weight after HIR in the NS group were significantly suppressed by TCV-309 pretreatment. Mean arterial blood pressure and renal tissue blood flow after HIR in the TCV group were significantly improved when compared with those in the NS group. These effects resulted in attenuation of structural hepatic and renal damage with the improvement of 7-day survival (62%). CONCLUSIONS The present study demonstrates that renal damage as well as critical liver injury is produced after reperfusion following 120 min of total hepatic ischemia. A PAF receptor antagonist may be therapeutically useful to protect against these types of damage via indirect modulation of plasma ET-1 levels.

Effects of an endothelin receptor antagonist TAK-044 on myocardial energy metabolism in ischemia/reperfused rat hearts

The purpose of this study was to investigate the effects of an endothelin-receptor antagonist TAK-044 on functional defects and metabolic derangement in myocardial ischemia/reperfusion injury. We sequentially measured high-energy phosphate metabolites and intracellular pH by phosphorus magnetic resonance spectroscopy during 35-min global ischemia followed by 60-min reperfusion in Langendorff-perfused rat hearts. TAK-044 (initial loading by 3 mg/kg followed by perfusion with 100 nM solution) was administered in two different ways: before ischemia or immediately after reperfusion. In addition, we investigated the effects of TAK-044 on functional defects and metabolic alterations induced by hydrogen peroxide (200 microM, 30 min). The recoveries of left ventricular developed pressure after reperfusion in TAK-044 groups (51 +/-12% in TAK-I, 61 +/- 12% in TAK-R) were better than in control (10 +/- 5% in control; p < 0.01). Increases in left ventricular end-diastolic pressure (LVEDP) in TAK-044 groups (22 +/- 5 mm Hg in TAK-I, 24 +/- 5 mm Hg in TAK-R) were less than in control (38 +/- 3 mm Hg; p < 0.01). Adenosine triphosphate (ATP) (33 +/- 5% in TAK-I, 28 +/- 4% in TAK-R) in TAK-044 groups were higher than in control (13 +/- 3%; p < 0.01). The creatine phosphokinase (CPK) release during reperfusion in TAK-044 groups (3.3 +/- 1.5 IU/g wet wt/60 min in TAK-I, 3.5 +/- 2.5 IU/g wet wt/60 min in TAK-R) were lower than in control (13.8 +/- 3.9 IU/g wet wt/60 min; p < 0.05). In contrast, TAK-044 did not attenuate the myocardial injury induced by hydrogen peroxide. TAK-044, even if administered simultaneous with coronary reperfusion, attenuated myocardial ischemia/ reperfusion injury. The energy-preservative effect of TAK-044 could be associated with the good functional recovery in ischemia/reperfused rat hearts.

Calcium-induced changes in chondroitin sulfate chains of urinary trypsin inhibitor

Urinary trypsin inhibitor (UTI) has several roles other than protease inhibition. It is suggested that UTI inhibits calcium influx in cultured cells and that the chondroitin sulfate chain of UTI may play an important role. In order to clarify the mechanistic features of this phenomenon, the chondroitin sulfate chain of UTI was analyzed by (1)H-NMR. The samples were highly purified UTI dissolved in D(2)O in the presence or absence of Ca(2+), Mg(2+) and Na(+). 1D-spectra were obtained and T(1) values of detected signals were estimated from the inversion-recovery method. The addition of Ca(2+) to UTI caused a chemical shift to downfield, line broadening and a reduction of T(1) values at several signals from chondroitin sulfate moiety (especially at axial H-2 of GalNAc), whereas Mg(2+) and Na(+) had no significant effect. Some of the signals in the linkage region of chondroitin sulfate chain showed marked line broadening by Ca(2+). The reduction of T(1) values implies formation of a complex. It is suggested that Ca(2+) generates the sulfate salt and interacts with other polar groups in the chondroitin sulfate chain, thereby causing bridging between UTI molecules. Several properties of UTI may be related to this interaction of Ca(2+) with chondroitin sulfate chains.