Detection of Tumor DNA in Serum of Colorectal Cancer Patients

We previously found p16 promoter methylation in DNA in the sera of 13 colorectal cancer patients out of 44 (30%) whose tumor DNA exhibited the methylation, using methylation-specific PCR (MSP). To examine whether the cancer detection rate could be improved by using a different tumor marker, we examined the K- ras status in 90 colorectal cancer patients using a mismatch ligation assay. Among the 31 patients showing K- ras gene mutations in their tumors, the same mutations were observed in serum DNA of 11 patients (35%). Among the 90 patients, 63 showed tumors positive for K- ras mutation or p16 promoter methylation, or both, and 22 had serum DNA positive for one or both. K- ras mutation was found even in serum DNA of patients with Dukes A cancer, suggesting that colorectal cancer might be detected even in patients without symptoms by using this ligation assay.     

Sensitivity of Human Cancer Cells to the New Anticancer Ribo-nucleoside TAS–106 Is Correlated with Expression of Uridine-cytidine Kinase 2

TAS–106 [l–(3– C -ethynyl-β- d - ribo -pentofuranosyl)cytosine] is a new anticancer ribo -nucleoside with promising antitumor activity. We have previously presented evidence suggesting that the TAS–106 sensitivity of cells is correlated with intracellular accumulation of the triphosphate of TAS–106, which may be affected both by cellular membrane transport mechanisms and uridine-cytidine kinase (UCK) activity. Since the presence of a UCK family consisting of two members, UCK1 and UCK2, has recently been reported in human cells, we investigated the relation between expression of UCK1 and UCK2 at both the mRNA and protein levels and UCK activity (TAS–106 phosphorylation activity) in a panel of 10 human cancer cell lines. Measurement of UCK activity in these cell lines revealed that it was well correlated with the cells' sensitivity to TAS–106. In addition, the mRNA or protein expression level of UCK2 was closely correlated with UCK activity in these cell lines, but neither the level of expression of UCK1 mRNA nor that of protein was correlated with enzyme activity. We therefore compared the protein expression level of UCK2 in several human tumor tissues and the corresponding normal tissues. Expression of UCK2 protein was barely detectable in 4 of the 5 human tumor tissues, but tended to be high in the pancreatic tumor tissue. It could not be detected at all in any of the normal tissues. Thus, expression of UCK2 appeared to be correlated with cellular sensitivity to TAS–106, and it may contribute to the tumor-selective cytotoxicity of TAS–106.     

Arrangement of orientation pinwheel centers around area 17/18 transition zone in cat visual cortex

In the primary visual cortex of higher mammals, orientation preferences are represented continuously except for singular points, so-called pinwheel centers. In spite of the uniqueness of orientation pinwheel centers, very little is known about the pattern of their arrangement. In this study we examined the arrangement of orientation pinwheel centers in the cat visual cortex by optical imaging of intrinsic signals. Our results demonstrate that orientation pinwheel centers are arranged in a unique geometric pattern around the area 17/18 transition zone: pinwheel centers of the same type are arranged in rows parallel to the transition zone, and rows of clockwise and counterclockwise pinwheel centers are arranged alternately. We suggest that the areal border imposes a strong restriction on the pattern formation of orientation preference maps in the visual cortex.     

Radical retropubic prostatectomy: time trends, morbidity and mortality in Japan

OBJECTIVES: To assess the time trends, morbidity and mortality of contemporary anatomical radical retropubic prostatectomy (RRP) in a multi-institutional study in Japan, where RRP has become more popular in the last decade. PATIENTS AND METHODS: Between January 1991 and August 1998, 638 patients underwent RRP at seven urological centres in Japan. Major complications (within 30 days of surgery) and the 30-day mortality were reviewed retrospectively. Of the patients, 12.9% were < 60 years old, 56.3% were 60-69 years old and 30.9% were >/= 70 years old (median age 67). Results The number of RRPs increased markedly, by more than sevenfold, from 1991-92 to 1996-97, mainly because there were more patients undergoing RRP in their sixth decade. The contribution of T1c disease increased in absolute and relative terms, from 13.9% in 1991-92 to 37.9% in 1997-98. Over time, the mean blood loss and the allogeneic transfusion rate decreased steadily. There was a trend toward more favourable outcomes for pathological variables (an increased percentage of organ-confined disease, decreased margin positivity and a decreased incidence of positive lymph node metastasis). The most common complications were wound-related (7.5%), or anastomotic leakage (4.1%). Major cardiopulmonary complications occurred in only two patients (0.31%, both pulmonary embolisms). One patient died from cerebral haemorrhage within 30 days of surgery, giving a mortality rate of 0.16%. CONCLUSION: s This study indicates a trend towards selecting patients most likely to benefit from RRP. Although the procedure is technically demanding, it can have an acceptably low rate of early complications, little mortality and need for allogeneic transfusion. The assessment of morbidity suggests a lower incidence of catastrophic thrombo-embolic and cardiac complications in Japanese patients than in Western men. The present data may be useful in decision-analysis models evaluating the role of therapy for Asian men with early-stage prostate cancer.     

Membrane current possessing the properties of a mechano-electric transducer current in inner hair cells of guinea-pig cochlea

We measured the membrane current possessing the properties of a mechano-electric transducer current in isolated inner hair cells of guinea-pig cochlea. In a free-standing hair bundle, depolarization to +80 mV evoked a stable outward current attributable to the opening of transducer channels, and repolarization to -80 mV evoked a transient inward current indicating adaptation. The time constant of adaptation increased as the membrane potential depolarized. Dihydrostreptomycin diminished both the outward and inward currents.     

Efficacy of a new coating material, PMEA, for cardiopulmonary bypass circuits in a porcine model

BACKGROUND: A new coating material, poly-2-methoxyethyl acrylate (PMEA), was developed to improve the biocompatibility of cardiopulmonary bypass (CPB) circuits. METHODS: To investigate the efficacy of the PMEA coating for CPB circuits, we compared PMEA-coated circuits (group P, n = 6) with uncoated circuits (group C, n = 6) and heparin (covalent-bonded heparin, Hepaface)-coated circuits (group H, n = 6) in a porcine CPB model. RESULTS: Platelet counts were significantly preserved in groups P and H compared with those in group C (P versus C, p < 0.05). The plasma levels of thrombin-antithrombin complex and bradykinin were significantly lower at 120 minutes in groups P and H than in group C (thrombin-antithrombin: P versus C, p < 0.05; bradykinin: P versus C, p < 0.05). The amount of fibrinogen adsorbed onto the hollow fibers was markedly less in group P than in groups C and H. CONCLUSIONS: The PMEA coating was equal to heparin coating in preventing reactions induced by CPB circuits, and might be superior to heparin coating in suppressing the adsorption of plasma proteins such as fibrinogen. Thus, PMEA coating may be a suitable means for improving the biocompatibility of CPB circuits.     

Nuclear factor-kappa B decoy attenuates neuronal damage after global brain ischemia: a future strategy for brain protection during circulatory arrest

OBJECTIVES: Recent studies have reported that cis element decoy oligodeoxynucleotides against nuclear factor-kappa B block the activation of genes that mediate ischemic injury. To improve brain protection during circulatory arrest in cardiac surgery, we evaluated the efficacy of nuclear factor-kappa B decoy oligodeoxynucleotides in preventing neuronal damage after global brain ischemia. METHODS: Hemagglutinating virus of Japan-liposome complex with fluorescein isothiocyanate-labeled nuclear factor-kappa B decoy oligodeoxynucleotides was injected through the carotid artery during 20 minutes of global brain ischemia in rats to evaluate the efficacy of transfecting the decoy oligodeoxynucleotides. The messenger RNA levels of several factors related to ischemia-reperfusion injury in the hippocampus were estimated by a real-time polymerase chain reaction method 1 hour after reperfusion. Neuronal damage was evaluated by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling staining and by using immunohistochemical study of microtubule-associated protein 2 in the hippocampus CA-1 region 7 days after ischemia. RESULTS: Introduction of the nuclear factor-kappa B decoy oligodeoxynucleotides into rat brain neurons through the carotid artery during global brain ischemia was markedly successful. The polymerase chain reaction study showed that the transfected nuclear factor-kappa B decoy oligodeoxynucleotides effectively inhibited the expression of tumor necrosis factor alpha interleukin 1 beta and intracellular adhesion molecule 1 messenger RNA 1 hour after global brain ischemia. Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling staining and microtubule-associated protein 2 immunohistochemistry showed that the transfected nuclear factor-kappa B decoy oligodeoxynucleotides significantly attenuated the neuronal damage 7 days after global brain ischemia. CONCLUSIONS: Therapeutic transfection of nuclear factor-kappa B decoy oligodeoxynucleotides during brain ischemia may be useful for attenuating neuronal damage, suggesting a strategy for cerebral protection against global ischemia.     

All-trans-retinoic Acid-dependent Inhibition of E-Cadherin-based Cell Adhesion with Concomitant Dephosphorylation of β-Catenin in Metastatic Human Renal Carcinoma Cells

We previously described an in vitro invasion assay model, using a monolayer of vascular endothelial cells grown on collagen gel, that mimics the metastatic abilities of the highly metastatic human renal carcinoma cell lines, MM-1,3 and 8 and their poorly metastatic counterparts, SN12C and Q-8. MM-1, 3 and 8 cells were observed to penetrate the monolayer of vascular endothelial cells and grew in a spreading or scattering manner with loose cell-cell contact on collagen gel or on vascular endothelial cells. SN12C and Cl-8 cells failed to penetrate and grew in a clustering manner with tight cell-cell contact. Treatment with all- trans -retinoic acid (ATRA) at non-toxic concentrations induced clustering or growth of MM-1, 3 and 8 cells on collagen gel or on vascular endothelial cells with tight cell-cell contact, and inhibited penetration. The clustering induced by ATRA was virtually blocked in the presence of anti-E cadherin antibody. E-Cadherin and β -catenin were each localized mainly at the cell-cell adherent junctions of colonizing cell populations that had been treated with ATRA. While the cellular levels of E-cadherin and β -catenin did not change significantly following ATRA treatment, the tyrosine residue of β -catenin was rapidly dephosphorylated. The concomitant administration of Na vanadate, an inhibitor of tyrosine dephosphorylase, inhibited both the ATRA-induced clustering and the dephosphorylation of β -catenin tyrosine. ATRA-induced clustering of MM-3 cells may be linked to the state of tyrosine phosphorylation of β -catenin.     

Pharmacokinetic Study of Carboplatin Given on a 5-Day Intravenous Schedule

We investigated whether carboplatin pharmacokinetics is altered when the drug is delivered daily over 5 days, compared to a single-day infusion. Carboplatin was infused in 11 patients with lung cancer, who were randomly assigned to 2 groups. In the first group, the agent was administered on a conventional single-day schedule in the first course and then on a 5-day schedule in the second course. In the second group, the order was reversed (crossover design). The dose was calculated using Calvert's formula with 24 h creatinine clearance (Ccr, ml/min) as a substitute for glomerular filtration rate (GFR): carboplatin (mg) = AUC X (Ccr+25), where AUC denotes the area under the concentration versus time curve (mg ml^–1 min). No difference of carboplatin clearance between the single-day and 5-day schedule was observed (94.8± 19.9 versus 96.1+29.9 ml/min, P =0.818, paired t test). The formula systematically overestimated the carboplatin clearance; the ratio of estimated clearance/ observed clearance ranged from 1.01 to 1.58 (median 1.28; 95% confidence interval, 1.18 to 1.39). We concluded that the individual dosing strategy based on renal function can be applied with a 5-day schedule as well as a single-day schedule. Carboplatin is overdosed when Ccr is substituted for GFR in Calvert's formula.