The characterization of [3H]sulpiride binding sites in rat striatal membranes

The characteristics of [3H]sulpiride binding to the D2 dopamine receptor in rat striatal membranes were examined under several conditions. In the absence of sodium ions, the specific binding of [3H]sulpiride could not be detected. In the direct binding experiment, at 25 degrees C, the affinity of [3H]sulpiride for D2 receptors was increased in a dose-dependent manner of sodium ions whereas magnesium ions have opposite effects on an affinity of [3H]sulpiride binding. The lowering incubation temperature (4 degrees C) also produced a further increase in affinity of the ligand. Under all conditions, [3H]sulpiride labeled a single homogenous site of the receptor. On the other hand, the result from quantitative analysis of agonist/[3H]sulpiride competition curves indicated an existence of high (RH) and low (RL) affinity states for agonists and the proportion of two-affinity states was modulated by guanosine triphosphate (GTP), magnesium ions and lowering temperatures. GTP, together with sodium ions, caused a full conversion of RH to RL, while an increase in the affinity for agonists with a partial conversion of RL to RH could be induced by magnesium ions at 25 degrees C. At a lower (4 degrees C) temperature, the agonist competition curve indicated an existence of a single agonist low-affinity state (RL) and then, the effects of GTP and magnesium ions in the agonist affinity observed at 25 degrees C were abolished. These results can be incorporated into a two-step, ternary complex model involving an inhibitory guanine nucleotide binding protein for the agonist and antagonist interaction with D2 receptors.(ABSTRACT TRUNCATED AT 250 WORDS)     

Relationship between plasma malondialdehyde levels and adenosine deaminase activities in preeclampsia

BACKGROUND: Preeclampsia is characterized by endothelial cell dysfunction, and lipid peroxidation and alterations of immune responses may be involved in the pathogenesis of this disease. The aim of the present study was to examine changes in plasma malondialdehyde (MDA) level, an indicator of lipid peroxidation, and adenosine deaminase (ADA) activity, as a marker of T-cell activation in preeclampsia, and evaluated the possible relationship between those parameters in the pathogenesis of preeclampsia. METHODS: Plasma levels of MDA, an end product of lipid peroxidation induced by reactive oxygen species, and ADA activities were measured in 26 women with preeclampsia and 26 normal pregnancies. RESULTS: In preeclampsia, plasma MDA level and ADA activity averaged 0.43 +/- 0.03 micromol/l and 15.8 +/- 0.8 U/l, respectively, which were significantly higher than those of normal pregnancy (0.31 +/- 0.02 micromol/l and 9.5 +/ -0.6 U/l, respectively) (P<0.05). In addition, plasma MDA level was positively correlated to ADA activity in preeclampsia (r=0.52, P<0.05). CONCLUSIONS: These results suggest that enhanced lipid peroxidation and T-cell activation, and the presence of possible interrelationship and cross talk between those parameters may be related at least partly to the pathogenesis of preeclampsia.     

Evaluation of serum iron in hemodialysis patients and its variation due to the difference of blood sampling time

Diurnal variations in serum iron concentration were examined to investigate the influence of sampling time in hemodialysis (HD) patients and healthy subjects. The serum iron concentration and TIBC of HD patients decreased significantly (p<0.01, p<0.01 respectively) compared to those of healthy subjects. Inversely, the serum ferritin concentration of HD patients increased significantly (p<0.01) compared to that of healthy subjects. These findings show the disturbance of iron transport system: under such condition intracellural iron transition out into peripheral blood stream is low in HD patients. Serum iron concentration in samples collected in the evening decreased significantly both in HD patients (p<0.05) and in healthy subjects (p<0.01). Diurnal variations in serum iron concentration reveal almost similar decrement in both groups. In HD patients, serum iron concentration of the blood samples collected on the third day morning after HD and second day morning after HD was examined to see the influence from changes of circulating plasma volume. The serum iron concentration and Hct value in the second day sampling increased significantly compared to the third day sampling (p<0.01, p<0.01 respectively). In addition, the serum iron concentration corrected by Hct in the second day sampling increased significantly (p<0.01) compared to the third day sampling. We conclude from our results that diurnal variations of serum iron concentration vary in sampling time in HD patients as well as in healthy subjects. We also deduct that there may be other factors concerning changes in circulating plasma volume.     

GPU-based fast pencil beam algorithm for proton therapy

Performance of a treatment planning system is an essential factor in making sophisticated plans. The dose calculation is a major time-consuming process in planning operations. The standard algorithm for proton dose calculations is the pencil beam algorithm which produces relatively accurate results, but is time consuming. In order to shorten the computational time, we have developed a GPU (graphics processing unit)-based pencil beam algorithm. We have implemented this algorithm and calculated dose distributions in the case of a water phantom. The results were compared to those obtained by a traditional method with respect to the computational time and discrepancy between the two methods. The new algorithm shows 5-20 times faster performance using the NVIDIA GeForce GTX 480 card in comparison with the Intel Core-i7 920 processor. The maximum discrepancy of the dose distribution is within 0.2%. Our results show that GPUs are effective for proton dose calculations.     

Chemosensitivity and Survival in Gastric Cancer Patients with Microsatellite Instability

Introduction  Conflicting data exist regarding the relevance of high-frequency microsatellite instability (MSI-H) for predicting the prognosis and benefits of 5-fluorouracil (5-FU)-based chemotherapy. This study investigated the usefulness of MSI as either a prognostic indicator or predictor of distinct clinical attributes regarding the use of adjuvant chemotherapy with 5-FU and its analogues in gastric cancer. Materials and methods  Data and tumor specimens were collected from 240 gastric cancer patients from 1993 to 2002. Five microsatellite loci were analyzed using a high-intensity microsatellite analysis reported previously. A Cox proportional hazard model was used to compare the clinical data and survival as well as any associations between MSI and 5-FU treatment status of patients with MSI or microsatellite stability (MSS) gastric cancers. A 3-(4,5-dimethyl-2-thiazolyl) -2,5-diphenyl-2H-tetrazolium bromide (MTT) assay was conducted in 168 cases to investigate chemosensitivity to 5-FU. Results  This analysis identified 22 MSI-H (9.4%), 25 MSI-L (10.7%), and 193 MSS (79.9%) tumors. Gastric cancer with MSI-H tended to have increased likelihood to show higher age, antral location of the tumor, and lymph vessel involvement (P < 0.05). Univariate analyses failed to show any difference between the MSI-H and MSS/MSI-L groups with respect to overall survival. Furthermore, survival after the administration of 5-FU did not correlate with MSI status, and MSI was not associated with 5-FU sensitivity by MTT assay. Conclusion  The results of this study indicate that MSI status has no clear influence on overall survival or response to 5-FU in gastric cancer.     

Inhibition of subgenomic hepatitis C virus RNA replication in HeLa cells

BACKGROUND/AIMS: Antiviral therapy such as combination interferon and ribavirin can eradicate hepatitis C virus (HCV) RNA by up to 40-50%. However, many patients still remain non-responders to this treatment for various reasons. The aim of this study was to evaluate the effect of interferon or ribavirin treatment on subgenomic HCV RNA replication in 'non-hepatic' HeLa cells. METHODOLOGY: Huh-7 or HeLa cells harboring HCV replicon were constructed by using cellular RNA of Huh-7 harboring HCV replicon RNAs, named as C13-3 cells. We also tested whether interferon or ribavirin can suppress HCV RNA in HeLa cells. RESULTS: Huh-7 or HeLa cells harboring HCV replicon RNAs were constructed by using cellular RNA of C13-3 cells than using in vitro-transcribed RNA. Ribavirin at 1 microg/mL or 10 microg/mL did not suppress colony formation in HeLa cells, but at 100 microg/mL suppression was observed. Interferon-alpha 2b suppressed HCV replication even at 1 U/mL. CONCLUSIONS: HeLa cells harboring HCV replicon RNAs also might be useful for the development of antiviral drugs.     

Analysis of the complete hepatitis B virus genome in patients with genotype C chronic hepatitis and hepatocellular carcinoma

Hepatitis B virus (HBV) genotype C and the basic core promoter (BCP) mutations were reported to be associated with the development of hepatocellular carcinoma (HCC). In this study the full sequences of HBV genomes were analyzed in order to find the other predictors of HCC development. We determined the full sequences of HBV genomes in 24 genotype C carriers who developed HCC (HCC group) at the beginning of follow-up and at the time of HCC diagnosis, and 20 patients who did not develop HCC (non-HCC group) served as a control. The number of nucleotide and amino acid substitutions in most regions was higher in the HCC group than in the non-HCC group, and the following substitutions and deletions were found more frequently in the HCC group than in the non-HCC group: G1317A and T1341C/A/G in the X promoter region were detected in 13 and six of the HCC cases, four and none of the non-HCC cases, respectively; and pre-S2 deletion was detected in eight HCC and none of the non-HCC cases. Compared with the wild type X promoter, the mutant type X promoters, M1 (G1317A), M2 (T1341C), and M4 (T1341G) showed increases in activity of 2.3, 3.8, and 1.4 times, respectively, in HepG2 cells. Substitutions and deletion of nucleotides of the HBV genome, especially the pre-S2 deletion and G1317A and T1341C/A/G mutations may be useful markers for predicting the development of HCC. ( Cancer Sci 2007; 98: 1921–1929)     

Antitumor activity of histone deacetylase inhibitors in non-small cell lung cancer cells: development of a molecular predictive model

To ascertain the potential for histone deacetylase (HDAC) inhibitor-based treatment in non-small cell lung cancer (NSCLC), we analyzed the antitumor effects of trichostatin A (TSA) and suberoylanilide hydroxamic acid (vorinostat) in a panel of 16 NSCLC cell lines via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. TSA and vorinostat both displayed strong antitumor activities in 50% of NSCLC cell lines, suggesting the need for the use of predictive markers to select patients receiving this treatment. There was a strong correlation between the responsiveness to TSA and vorinostat (P < 0.0001). To identify a molecular model of sensitivity to HDAC inhibitor treatment in NSCLC, we conducted a gene expression profiling study using cDNA arrays on the same set of cell lines and related the cytotoxic activity of TSA to corresponding gene expression pattern using a modified National Cancer Institute program. In addition, pathway analysis was done with Pathway Architect software. We used nine genes, which were identified by gene-drug sensitivity correlation and pathway analysis, to build a support vector machine algorithm model by which sensitive cell lines were distinguished from resistant cell lines. The prediction performance of the support vector machine model was validated by an additional nine cell lines, resulting in a prediction value of 100% with respect to determining response to TSA and vorinostat. Our results suggested that (a) HDAC inhibitors may be promising anticancer drugs to NSCLC and (b) the nine-gene classifier is useful in predicting drug sensitivity to HDAC inhibitors and may contribute to achieving individualized therapy for NSCLC patients.