Safe esophageal reconstruction by ileocolic interposition.

Many techniques have been proposed for esophageal reconstruction after esophagectomy when a gastric tube cannot be employed. There are two essential criteria for such a substitute: substitute length and sufficient blood supply. We propose ileocolic interposition as an easy and safe option. Two technical aspects contributing to the high success rate of this method are the preservation of an intact arterial network allowing normal blood flow to the ileocolic area, and the ability to quantify blood flow using a Doppler pulse flow meter in six cases. These are enabled by a long (up to 20cm) ileocolic segment. The preservation of the right colic artery is important, because its interruption would reduce blood supply to the long ileum segment. Between July 2003 and October 2008, we used this method in six patients in whom a gastric tube was not an option. We assessed perioperative morbidity and swallowing difficulties in each patient, quantifying dysphagia on scale of 0 to 4. There was no mortality and no anastomotic leak. There was one wound infection, and in one patient, recurrent nerve paralysis was observed. The postoperative hospital stay was 29.5 ± 10.8 days. The average dysphagia score for the six patients was 0.17 ± 0.41 after the operation. All patients can eat normally, without any dietary limitations. Ileocolonic interposition after esophagectomy requires careful assessment of the vascular supply. In this small series, morbidity was low and there was no perioperative mortality. We believe that this is an easy and safe method of reconstruction after esophagectomy in cases in whom a gastric tube cannot be used as a substitute.

[Investigation of the local heating caused by a closed conducting loop at clinical MR imaging: Phantom study].

PURPOSE: Several reports have suggested that unusual thermal injuries in magnetic resonance (MR) imaging have occurred due to a closed conducting loop formed accidentally in a part of the patient's body. In this study, we investigated the relationship between the increases in temperature and several parameter settings for MR imaging by use of a human body-equivalent phantom. METHOD AND MATERIALS: A standard clinical 1.5T MR system (SIGNA HORIZON; GE) and a pelvic phased-array coil were used. The human body-equivalent phantom (agar, 0.9% saline, antiseptic) simulated a part of the pelvis and both femurs in a patient. A closed conducting loop could be reproduced when two ends of femurs contacted each other at a point, so that we could measure the temperature changes without and with a closed conducting loop. The temperature of the phantom was measured at the contact point of a closed conducting loop and the center of phantom by use of an optical fiber thermometer which was immune to the influences of radiofrequency (RF) and magnetic and electronic fields. We tested two imaging sequences of spin echo (SE) and fast spin echo (FSE) with 60 minutes of scanning time. In addition to the standard imaging sequences we measured temperature changes without the RF irradiation or gradient magnetic fields. The average temperature changes were recorded from five measurements which were repeated at intervals of more than one day. RESULTS: When the closed conducting loop was reproduced, the temperatures at the contact point significantly increased (p<0.001) compared with the temperatures at the center of phantom. The temperature changes at 60 minutes of scanning time were 7.0 and 8.1 degrees C by use of the SE and FSE, respectively. There were no significant temperature changes when the imaging was performed without the RF irradiation. CONCLUSION: Our result obtained by use of a human body-equivalent phantom demonstrated that local heating, which can lead to thermal injuries accidentally, could occur when a closed conducting loop was formed in part of the patient body. CLINICAL RELEVANCE/APPLICATION: Radiologists should be more careful about local heating which can occur in patients during clinical MR imaging by a closed conducting loop.

Cellular thiol status-dependent inhibition of tumor cell growth via modulation of p27(kip1) translocation and retinoblastoma protein phosphorylation by 1'-acetoxychavicol acetate.

1'-Acetoxychavicol acetate (ACA) has been shown to inhibit tumor cell growth, but there is limited information on its effects on cell signaling and the cell cycle control pathway. In this study, we sought to determine how ACA alters cell cycle and its related control factors in its growth inhibitory effect in Ehrlich ascites tumor cells (EATC). ACA caused an accumulation of cells in the G1 phase and an inhibition of DNA synthesis, which were reversed by supplementation with N-acetylcysteine (NAC) or glutathione ethyl ester (GEE). Furthermore, ACA decreased hyperphosphorylated Rb levels and increased hypophosphorylated Rb levels. NAC and GEE also abolished the decease in Rb phosphorylation by ACA. As Rb phosphorylation is regulated by G1 cyclin dependent kinase and CDK inhibitor p27(kip1), which is an important regulator of the mammalian cell cycle, we estimated the amount of p27(kip1) levels by western blotting. Treatment with ACA had virtually no effect on the amount of p27(kip1) levels, but caused a decrease in phosphorylated p27(kip1) and an increase in unphosphorylated p27(kip1) as well as an increase in the nuclear localization of p27(kip1). These events were abolished in the presence of NAC or GEE. These results suggest that in EATC, cell growth inhibition elicited by ACA involves decreases in Rb and p27(kip1) phosphorylation and an increase in nuclear localization of p27(kip1), and these events are dependent on the cellular thiol status.

Estimation of rhG-CSF absorption kinetics after subcutaneous administration using a modified Wagner-Nelson method with a nonlinear elimination model.

The clearance of recombinant human granulocyte-colony stimulating factor (rhG-CSF) is known to decrease with dose increase, and to be saturable. The average clearance after intravenous administration will be lower than that after subcutaneous administration. Therefore, the apparent absolute bioavailability with subcutaneous administration calculated from the AUC ratio is expected to be an underestimate. The absorption pharmacokinetics after subcutaneous administration was examined using the results of the bioequivalency study between two rhG-CSF formulations with a dose of 2 microg/kg. The analysis was performed using a modified Wagner-Nelson method with the nonlinear elimination model. The apparent absolute bioavailability for subcutaneous administration was 56.9 and 67.5% for each formulation, and the ratio between them was approximately 120%. The true absolute bioavailability was, however, estimated to be 89.8 and 96.9%, respectively, and the ratio was approximately 108%. The absorption pattern was applied to other doses, and the predicted clearance values for subcutaneous and intravenous administrations were then similar to the values for several doses reported in the literature. The underestimation of bioavailability was around 30%, and the amplification of difference was 2.5 times, from 8 to 20%, because of the nonlinear pharmacokinetics. The neutrophil increases for each formulation were identical, despite the different bioavailabilities. The reason for this is probably that the amount eliminated through the saturable process, which might indicate the amount consumed by the G-CSF receptor, was identical for each formulation.

Proton MR spectroscopy of the brain in patients treated with TIPS.

PURPOSE: To evaluate the utility of proton MR spectroscopy (MRS) for the early detection of hepatic encephalopathy (HE) after transjugular intrahepatic portosystemic shunting (TIPS). MATERIAL AND METHODS: Six patients, who underwent TIPS for treatment of portal hypertension, were examined by MRS I week before and 1 week after TIPS. They were simultaneously clinically examined for number connection test, blood NH3 level, liver function test and the Fischer ratio. RESULT: Three of 6 patients showed overt HE 1 to 5 weeks after TIPS and the other 3 patients did not show overt HE. The overt HE group showed the larger ratio of the amounts of glutamine and glutamate/myo-inositol (Glx/MI) than that of non-overt HE group (p<0.05). CONCLUSION: The Glx/MI ratio estimated by MRS was useful for early detection of HE after TIPS.

Muscarinic receptor-mediated dual regulation of ADP-ribosyl cyclase in NG108-15 neuronal cell membranes.

Cyclic ADP-ribose (cADP-ribose) is an endogenous modulator of ryanodine-sensitive Ca2+ release channels. An unsolved question is whether or not cADP-ribose mediates intracellular signals from hormone or neurotransmitter receptors. The first step in this study was to develop a TLC method to measure ADP-ribosyl cyclase, by which conversion of [3H]NAD+ to [3H]cADP-ribose was confirmed in COS-7 cells overexpressing human CD38. A membrane fraction of NG108-15 neuroblastoma x glioma hybrid cells possessed ADP-ribosyl cyclase activity measured by TLC. Carbamylcholine increased this activity by 2.6-fold in NG108-15 cells overexpressing m1 or m3 muscarinic acetylcholine receptors (mAChRs), but inhibited it by 30-52% in cells expressing m2 and/or m4 mAChRs. Both of these effects were mimicked by GTP. Pretreatment of cells with cholera toxin blocked the activation, whereas pertussis toxin blocked the inhibition. Application of carbamylcholine caused significant decreases in NAD+ concentrations in untreated m1-transformed NG108-15 cells, but an increase in cholera toxin-treated cells. These results suggest that mAChRs couple to ADP-ribosyl cyclase within cell membranes via trimeric G proteins and can thereby control cellular function by regulating cADP-ribose formation.

Plasma-gelsolin-binding sites on the actin sequence.

Plasma gelsolin was cross-linked to fluorescently labeled actin in order to identify plasma-gelsolin-binding sites on the primary sequence of actin. Plasma gelsolin can be cross-linked to actin with 1-ethyl-3-[3-(dimethyl-amino)propyl]carbodiimide (EDC), resulting in the formation of 1:1 and 1:2 plasma gelsolin:actin cross-linked complexes with apparent molecular masses of 130 kDa and 180 kDa respectively. The cross-linked complexes were isolated separately, partially digested with cyanogen bromide and subjected to sodium dodecyl sulfate gel electrophoresis to analyze fluorescent fragments. The electrophoretic pattern showed that fluorescent CNBr fragments obtained from a free actin molecule were all found in those obtained from both the complexes. Since the fluorescent probe was attached to an actin molecule through the penultimate cysteine residue (Cys-374), the agreement in the fluorescent patterns indicated that the NH2-terminal CNBr fragments of both the actin molecules were involved in cross-linking with plasma gelsolin. This was also suggested by hydroxylamine cleavage of the two complexes as the cleavage gave the fluorescent 41-kDa fragment which could not be produced unless plasma gelsolin was cross-linked at the NH2-terminal segment comprising 12 amino acids. Since EDC cross-links an amino group with a carboxyl group only when they are direct contact, the characteristic acidic amino acid residues at the NH2 terminus of actin are suggested to participate in binding plasma gelsolin.

Magnesium ion-induced changes in the binding mode of adenylates to chloroplast coupling factor 1.

The effect of Mg2+ on the binding of adenylates to isolated chloroplast coupling factor 1 (CF1) was studied using CD spectrometry and ultrafiltration. At adenylate concentrations smaller than 100 muM, one mole of CF1 binds three moles of ATP (or ADP) regardless of the presence of Mg2+. In the presence of Mg2+, the first two ATP's bind to CF1 independently with the same binding constant of 2.5 X 10(-1) muM-1, then the third ATP binds with a much higher affinity of 10 muM-1. In the absence of Mg2+, the first ATP binds to CF1 with a binding constant of 2.5 X 10(-1) muM-1 then the other two ATP's bind less easily with the same binding constant of 4.0 X 10(-2) muM-1. The binding mode of ADP to CF1 is quite similar to that of ATP. In the presence of Mg2+, the binding constants of the first two ADP's are both 7.6 X 10(-2) muM-1, that of the third ADP being 4.0 muM-1. In the absence of Mg2+, the binding constant of the first ADP is 7.6 X 10(-2) muM-1, the constants of the other two ADP's both being 4.0 X 10(-2) muM-1. AMP caused a negligible change in CD.