Whole sentinel lymph node analysis by a molecular assay predicts axillary node status in breast cancer.

BACKGROUND: The one-step nucleic acid amplification (OSNA) assay is a rapid procedure for the detection of lymph node (LN) metastases using molecular biological techniques. The aim of this study was to assess the reliability of the whole sentinel lymph node (SLN) analysis by the OSNA assay as a predictor of non-SLN metastases. METHODS: Consecutive 742 patients with breast cancer were enroled in the study. The association of non-SLN or ≥4 LN metastases with clinicopathological variables was investigated using multivariate logistic analysis. RESULTS: In total, 130 patients with a positive SLN who underwent complete axillary LN dissection were investigated. The frequency of non-SLN metastases in patients who were OSNA+ and ++ was 19.3% and 53.4%, respectively, and that in patients with ≥4 LN metastases who were OSNA+ and ++ was 7.0% and 27.4%, respectively. The cytokeratin 19 (CK19) mRNA copy number (≥5.0 × 10(3); OSNA++) in the SLN was the most significant predictors of non-SLN metastases (P=0.003). The CK19 mRNA copy number (≥1.0 × 10(5)) in the SLN was the only independent predictor of ≥4 LN metastases (P=0.014). CONCLUSION: Whole SLN analysis using the OSNA assay could become a valuable method for predicting non-SLN and ≥4 LN metastases.

Human papillomavirus detected in female breast carcinomas in Japan.

To investigate the aetiological role of human papillomavirus (HPV) in breast cancer, we examined the presence, genotype, viral load, and physical status of HPV in 124 Japanese female patients with breast carcinoma. Human papillomavirus presence was examined by PCR using SPF10 primers, and primer sets targeting the E6 region of HPV-16, -18, and -33. The INNO-LiPA HPV genotyping kit was used to determine genotype. Human papillomavirus DNA was detected in 26 (21%) breast carcinomas. The most frequently detected HPV genotype was HPV-16 (92%), followed by HPV-6 (46%), HPV-18 (12%), and HPV-33 (4%). In 11 normal epithelium specimens adjacent to 11 HPV-16-positive carcinomas, 7 were HPV-16-positive. However, none of the normal breast tissue specimens adjacent to HPV-negative breast carcinomas were HPV-positive. The real-time PCR analysis suggested the presence of integrated form of viral DNA in all HPV-16-positive samples, and estimated viral load was low with a geometric mean of 5.4 copies per 10(4) cells. In conclusion, although HPV DNA was detected in 26 (21%) breast carcinomas and, in all HPV-16-positive cases, the HPV genome was considered integrated into the host genome, their low viral loads suggest it is unlikely that integrated HPV is aetiologically involved in the development of Japanese breast carcinomas that we examined.

Codeine presynaptically inhibits the glutamatergic synaptic transmission in the nucleus tractus solitarius of the guinea pig.

Although codeine is the most prominent and centrally acting antitussive agent, the precise sites and mode of its action have not been fully understood yet. In the present study, we examined the effects of codeine on synaptic transmission in second-order neurons of the nucleus tractus solitarius (NTS), which is the first central relay site receiving tussigenic afferent fibers, by using whole-cell patch-clamp recordings in guinea-pig brainstem slices. Codeine (0.3-3 mM) significantly decreased the amplitude of excitatory postsynaptic currents (EPSCs) evoked by electrical stimulation of the tractus solitarius in a naloxone-reversible and concentration-dependent manner, but it had no effect on the decay time of evoked EPSCs (eEPSCs). The inhibition of eEPSCs was accompanied by an increased paired-pulse ratio of two consecutive eEPSCs. The inward current induced by application of AMPA remained unchanged after codeine application. A voltage-sensitive K+ channel blocker, 4-aminopyridine (4-AP) attenuated the inhibitory effect of codeine on eEPSCs. These results suggest that codeine inhibits excitatory transmission from the primary afferent fibers to the second-order NTS neurons through the opioid receptors that activate the 4-AP sensitive K+ channels located at presynaptic terminals.

L-DOPA inhibits excitatory synaptic transmission in the rat nucleus tractus solitarius through release of dopamine.

The mode of action of L-DOPA on excitatory synaptic transmission in second-order neurons of the nucleus tractus solitarius (NTS) was studied using the rat brainstem slices. Superfusion of L-DOPA (10µM) reduced the frequency of miniature excitatory postsynaptic currents (mEPSCs) without any effect on the amplitude. A low concentration (1µM) was ineffective on the mEPSCs, and the highest concentration (100µM) exerted a stronger inhibitory effect. L-DOPA (10µM) decreased the amplitude of EPSCs (eEPSCs) evoked by electrical stimulation of the tractus solitarius and increased the paired-pulse ratio. The inhibitory effects of L-DOPA on mEPSCs and eEPSCs were similar to those of dopamine (100µM). The effects of L-DOPA were blocked by a competitive antagonist, L-DOPA methyl ester (100µM) and also by a D2 receptor antagonist, sulpiride (10µM), while those of dopamine were blocked by the latter but not by the former. In reserpine (5mg/kg, s.c.)-treated rats, the effects of L-DOPA on both mEPSCs and eEPSCs were completely abolished, but those of dopamine remained unchanged. The present results suggest a possibility that L-DOPA may induce the release of dopamine from the axon terminals in the NTS and the released dopamine suppresses the glutamatergic transmission through activation of the presynaptic D2 receptors.

Ryanodine receptor/Ca(2+) release mechanisms in rhythmically active respiratory neurons of cats in vivo.

The cytosolic Ca(2+) released from internal stores is important for distinctive cell functions. To assess the role of ryanodine/Ca(2+) releasing mechanisms in the rhythmic activity of respiratory neurons, effects of intracellular injection of ryanodine on the membrane potential trajectory of postinspiratory and augmenting inspiratory neurons were investigated in unanesthetized, decerebrate, paralyzed and artificially ventilated cats. Ryanodine injection hyperpolarized the membrane and decreased input resistance throughout the respiratory cycle in both types of respiratory neurons. Specifically, membrane repolarization during postinspiration was accelerated in postinspiratory neurons, and the large hyperpolarization at the onset of postinspiration was increased in augmenting inspiratory neurons. Spike-afterhyperpolarization consisting of a fast, early component and slow, late component increased in size after ryanodine, resulting in prolongation of inter-spike intervals and decrease of burst discharge. Intracellular injection of caffeine produced similar effects on these respiratory neurons, and Ruthenium Red, an antagonist of ryanodine receptors, had opposite effects. Immunoreactivity for ryanodine receptors was detected in all respiratory neurons labeled intracellularly with neurobiotin. These results demonstrate that ryanodine-sensitive Ca(2+) stores modulate the periodic membrane potential fluctuations and spike activity in respiratory neurons.

A new family of heparin-binding growth/differentiation factors: increased midkine expression in Wilms' tumor and other human carcinomas.

Midkine (MK) and heparin-binding growth-associated molecule/pleiotrophin form a new family of heparin-binding growth/differentiation factors. We studied MK gene expression in human tumors. In normal human reference tissues, MK was highly expressed in the mucosal tissue of the small intestine, moderately in the thyroid, weakly in the tissues of the lung, colon, stomach, kidney, and spleen, and not at all in the liver. All of 6 surgically removed specimens of Wilms' tumor highly expressed MK. Also, a moderate to intense level of MK expression was noted in the majority of surgically removed hepatocellular carcinomas. The MK mRNA level was analyzed in a number of cultured and nude mice-transplanted lines of human tumors. In stomach, colon, pancreatic, lung, and esophageal carcinomas, a moderate to high level of MK expression was found in the majority of them. These results suggest an important role of MK in the development and/or biological behavior of tumors and raised a possibility to use MK as a diagnostic marker. Heparin-binding growth associated molecule/pleiotrophin mRNA was low or scarcely detectable in samples analyzed thus far except for significant levels of the expression that were observed in PA-1 teratocarcinoma cells and in some surgical specimens of Wilms' tumor.

Correlation between thymidine phosphorylase expression and prognosis in human renal cell carcinoma.

PURPOSE: Thymidine phosphorylase (TP) is identical to platelet-derived endothelial cell growth factor (PD-ECGF) and has angiogenic activity. We examined whether TP expression in renal cell carcinoma (RCC) is associated with microvessel density as a marker of angiogenesis, clinicopathologic characteristics, and outcome. PATIENTS AND METHODS: The enzymatic activity and expression of TP were examined in 18 RCCs and 19 kidney tissues not grossly involved with tumor from 24 patients with 13 paired samples and 11 unpaired samples by spectrophotometry and immunoblotting. The relationship between TP expression and microvessel density was assessed by immunohistochemistry in 133 RCCs. RESULTS: The median enzymatic activity of TP in RCCs was nine fold higher than that in nonneoplastic kidney tissues (P < .001). Similar results were obtained by immunoblot analysis. According to the TP staining profile, tumors were classified as no or low, intermediate, or high TP-expressing tumors. TP positivity was significantly correlated with microvessel density. TP expression was correlated with tumor grade, but there was no significant association between TP expression and other clinicopathologic characteristics. TP expression as a prognostic variable was studied using Cox's proportional hazards model. TP overexpression was an independent prognostic factor (hazards ratio, 3.95; 95% confidence interval, 0.98 to 15.89; P = .039) as were nodal category, metastases category, tumor grade, and venous invasion. CONCLUSION: These findings suggest that TP expression is correlated with microvessel density in RCC and is an unfavorable independent prognostic factor. The future development and characterization of TP inhibitors may provide a novel approach to the therapy of RCC.

Purification and characterization of human T-cell leukemia virus type I protease produced in Escherichia coli.

Human T-cell leukemia virus type I (HTLV-I) protease has been purified to homogeneity from a strain of recombinant Escherichia coli. The protease was expressed as a larger precursor, which was autoprocessed to form a mature protease. Protein chemical analyses revealed the coding sequence of mature protease, which agreed with the putative sequence predicted from the sequence of bovine leukemia virus protease. The purified protease processed the natural substrate gag precursor (p53) to form gag p19 and gag p24. The protease activity was inhibited by pepstatin A. These results provide direct evidence that this protease belongs to the aspartic protease family and has an activity consistent with the protease in HTLV-I virion.

Sphingosine induces apoptosis in androgen-independent human prostatic carcinoma DU-145 cells by suppression of bcl-X(L) gene expression.

Our recent studies have suggested that sphingosine, an endogenous protein kinase C (PKC) inhibitor, may mediate apoptosis induced by a phorbol ester (PMA) in human promyelocytic leukemia HL-60 cells [Ohta et al. Cancer Res. 1995;55:691-697], and that the apoptotic induction by both PMA and sphingosine is accompanied by down-regulation of bcl-2, a gene which acts to prevent apoptotic cell death [Sakakura et al. FEBS Lett. 1996;397:177-180]. In this study, we examined the sphingosine-induced apoptosis of the androgen-independent human prostatic carcinoma cell line DU-145, which expresses bcl-X(L) and Bax but not bcl-2, and found that treatment of DU-145 cells with sphingosine suppressed bcl-X(L) in both mRNA and protein levels but did not change bax expression at all. In contrast, in apoptotic cells treated with a PKC inhibitor, staurosporine, no effect on bcl-X(L) or bax expression was observed. The initial metabolites of sphingosine in the cells, ceramide and sphingosine 1-phosphate, failed to induce apoptosis. These results indicate that, in DU-145 cells, sphingosine, but not its metabolites, induces apoptosis through down-regulation of bcl-X(L), independently of PKC inhibition. Our present results, together with previous observations, strongly suggest that apoptosis regulatory genes differ according to cell type and apoptosis induction through sphingosine is accompanied by inhibition of either bcl-2 or bcl-X(L) activity in these cells.

BK channel activation by NS-1619 is partially mediated by intracellular Ca2+ release in smooth muscle cells of porcine coronary artery.

1. Effects of NS-1619, an opener of large conductance Ca2+-activated K+ (BK) channel, on intracellular Ca2+ concentration ([Ca2+]i) and membrane potential were examined in single myocytes freshly isolated from porcine coronary artery. 2. Under current clamp mode, the application of 1-30 microM NS-1619 hyperpolarized the membrane in concentration-dependent manner. The NS-1619-induced hyperpolarization was abolished by the presence of 100 nM iberiotoxin. 3. Application of 1-10 microM NS-1619 hyperpolarized the membrane by approximately 6 mV or less but did not change significantly the [Ca2+]i. When membrane hyperpolarization of 12 mV or so was caused by 30 microM NS-1619, [Ca2+]i was unexpectedly increased by approximately 200 nM. This increase in [Ca2+]i and the concomitant outward current activation were also observed under voltage-clamp at holding potential of -40 mV. 4. The increase in [Ca2+]i by 30 microM NS-1619 occurred mainly in peripheral regions than in the centre of the myocytes. The removal of extracellular Ca2+ affected neither the membrane hyperpolarization nor the increase in [Ca2+]i. 5. In the presence of 10 mM caffeine and 10 microM ryanodine, the increase in [Ca2+]i by 30 microM NS-1619 was not observed and the membrane hyperpolarization was reduced to approximately 67% of the control. 6. These results indicate that the opening of BK channels by NS-1619 at 30 microM, which is the most frequently used concentration of this agent, is partly due to Ca2+ release from caffeine/ryanodine-sensitive intracellular storage sites but is mainly due to the direct activation of the channels.

Overcoming of multidrug resistance by introducing the apoptosis gene, bcl-Xs, into MRP-overexpressing drug resistant cells.

Multidrug resistance associated protein (MRP) is one of drug transport membranes that confer multidrug resistance in cancer cells. Multidrug resistance has been known to be associated with resistance to apoptosis. In this study, using MRP overexpressing multidrug resistant nasopharyngeal cancer cells, we examined the expression of apoptosis related genes including p53, p21WAF1, bax and bcl-Xs between drug sensitive KB and its resistant KB/7D cells. We also examined whether the introduction of apoptosis related gene could increase the sensitivity to anticancer drugs in association with apoptotic cell death. The relative resistances to anticancer drugs in KB/7D cells evaluated by IC50 values were 3.6, 61.3, 10.4 and 10.5 to adriamycin (ADM), etoposide (VP-16), vincristine (VCR) and vindesine (VDS), respectively. The resistance to anticancer drugs in KB/7D cells was associated with the attenuation of internucleosomal DNA ladder formation in apoptosis. Of important, the mRNA expression of bcl-Xs gene in KB/7D cells was decreased in one-fourth as compared to that of KB cells among the apoptosis genes. The mRNA expression of bcl-Xs gene in a bcl-Xs transfected clone (KB/7Dbcl-Xs) was increased about 2-fold compared to that of KB/7Dneo cells, while the mRNA expression of MRP gene was not significantly different in KB/7bcl-Xs and KB/7Dneo cells. The sensitivities to anticancer drugs including ADM, VCR and VDS except VP-16 were increased in KB/7Dbcl-Xs cells, in turn, the relative resistance in KB/7Dbcl-Xs cells was decreased to 1.4, 4.0, and 3.0 in ADM, VCR and VDS, respectively, as compared to those of KB/7Dneo cells. Of interest, the studies on the accumulation of [3H]VCR showed that the decrease of [3H]VCR accumulation in KB/7Dbcl-Xs was not significantly different from that of KB/7Dneo cells. Collectively, these results indicated that the mechanism(s) of drug resistance in KB/7D cells could be explained at least by two factors: a) reduced drug accumulation mediated by MRP; b) resistance to apoptosis due to the decreased expression of the bcl-Xs gene. These results also indicated that the multidrug resistance mediated by MRP might be partially overcome by introducing apoptosis gene into drug resistant cells without modulation of MRP function in drug accumulation.

Activation and the interaction of proapoptotic genes in modulating sensitivity to anticancer drugs in gastric cancer cells.

Taxotere (Docetaxel) is a novel microtubulin inhibitor which is currently in phase II/III clinical trial. We found that the sensitivity to taxotere was correlated with apoptotic cell death determined by the internucleosomal DNA ladders in gastric cancer cell lines. The treatment of taxotere activated proapoptotic genes such as bcl-Xs and bax genes. The relationship between the mRNA induction of bcl-Xs and bax genes and the internucleosomal DNA ladders by taxotere was significant, respectively (p<0.05). The introduction of bcl-Xs gene into MKN45 gastric cancer cells increased the sensitivity to VP-16 and taxotere 2-3-fold in the IC50 values, whereas the introduction of bax gene increased the sensitivity to CDDP, VP-16 and taxotere 2-5-fold in the IC50 values, as compared to that of the Neo-transfected MKN45 cells. The mRNA overexpression of bax gene was found in the bcl-Xs-transfected cells. Likewise, the mRNA overexpression of bcl-Xs gene was also found in the bax-transfected cells. These results indicate that the activation of bcl-2 family genes such as bcl-Xs and bax plays a crucial role in modulating apoptotic cell death in the sensitivity to anticancer drugs, and suggest that these proapoptotic genes might interact in the up-regulation for activating downstream signals leading to apoptosis in gastric cancer cells.

A phase II trial of low dose administration of 5-fluorouracil and cisplatin in patients with advanced and recurrent gastric cancer.

The clinical efficacy of chemotherapy for patients with advanced gastric cancer has not been established. We investigated in a phase II study the combination chemotherapy of low dose 5-fluorouracil (5-FU) and cisplatin (low dose FP) to evaluate its clinical efficacy in terms of response, quality of life and survival in 43 gastric cancer patients including 29 advanced and 14 recurrent cases. The administration of 5-FU was done by continuous intravenous infusion for 28 consecutive days with a dose of 250 mg/m2, while the administration of cisplatin was done by 1-h intravenous drip-infusion for 5 consecutive days and 2-day intervals per week with a dose of 3.5 mg/m2, that was repeated for 4 weeks in one cycle. The response rate in advanced cases was 48.3%, evaluated in 14 cases of partial response (PR), whereas its response rate in recurrent cases was 35.7%, evaluated in 5 cases of PR. The most effective lesions for low dose FP chemotherapy were primary lesion and lymph node metastasis. The quality of life assessed by performance status and oral intake was improved in 13.8% and 37.9% of advanced cases, and 21.4% and 28.6% of recurrent cases, respectively, as compared to those of pretreatment. The median survival time and 1-year survival rate were 6 months, 21.6% in advanced cases and 10 months, 28.8% in recurrent cases, respectively. The major adverse effect was observed in gastrointestinal toxicity and leukopenia, and the all toxicities were less than grade 2, that were controllable during the treatment. These results indicated that the combination chemotherapy of low dose administration of 5-FU and cisplatin might have therapeutic efficacy in tumor response and offer improvement in quality of life in patients with advanced and recurrent gastric cancer.

Cloning of an alternative form of plakoglobin (gamma-catenin) lacking the fourth armadillo repeat.

Plakoglobin is a member of a protein family with a repeating amino acid motif called the armadillo repeat, and is a cytoplasmic protein found in both adherens junctions and desmosomes. Little is known about its function, but it has been shown to form distinct complexes with cadherins or desmosomal cadherins. Also, plakoglobin has been shown to form a complex with APC, a tumor suppressor gene product. We have isolated a cDNA clone encoding plakoglobin by means of the polymerase chain reaction (PCR) from a human transitional carcinoma cell line. The cDNA has the same nucleotide sequence as the previously published one [Franke et al. (1989) Proc. Natl. Acad. Sci. USA 86, 4027-4031], except that it has a deletion of 120 bp. The deleted sequence encodes the fourth armadillo repeat. Southern blot analysis of genomic DNA revealed that there is a single copy of the plakoglobin gene per haploid genome. Cloning and sequencing of a genomic DNA fragment containing the 120-bp deletion and the surrounding sequences revealed that these sequences are encoded by a single exon sequence. PCR amplification of the genomic DNA fragment of the corresponding region excluded the possible presence of the 120-bp deletion in the gene. Therefore the variant form is most likely derived through alternative splicing of precursor RNA transcripts in an exon sequence.

Identification of the replication region of the Lactobacillus acidophilus plasmid pLA106.

The complete nucleotide sequence of plasmid pLA106 (2862 bp) from Lactobacillus acidophilus TK8912 was determined. Based on this sequence, the location of the genes for mobilization-plasmid recombination protein (mob), replication origin (ori), transcriptional repressor protein (repA) and replication initiation protein (repB) were predicted. Deletion analysis showed that the 1.4-kb PstI-EcoRV fragment carrying the ori, repA and repB genes is able to replicate in Lactobacillus and Escherichia coli cells. The plasmid pLA106 appears to have most features of the pLS1/pE194 plasmid family.

In vitro bactericidal activities of beta-lactamases, amikacin, and fluoroquinolones against Pseudomonas aeruginosa biofilm in artificial urine.

OBJECTIVES: To compare bactericidal activities of antimicrobial agents against Pseudomonas aeruginosa biofilms by employing an in vitro model of catheter-associated infection because such infections are refractory to antimicrobial treatment. METHODS: Bactericidal activities of piperacillin (PIPC), ceftazidime (CAZ), panipenem (PAPM), amikacin (AMK), ciprofloxacin (CPFX), and levofloxacin (LVFX) were examined against a P. aeruginosa biofilm generated on a Teflon catheter in artificial urine. The colony-forming activities of biofilm bacteria were determined for 48 hours during the treatment with each drug at concentrations of 1 up to 128 times the minimal bactericidal concentration (MBC), and time-kill curves were constructed by plotting the viable cell counts against time. RESULTS: Although CAZ was more bactericidal to the biofilm bacteria than PIPC, the biofilm bacteria still remained on the catheter during CAZ treatment at a concentration 128 times the MBC for 48 hours. Biofilm bacteria were completely eradicated within 48 hours by treatment with PAPM and AMK at a concentration 64 and 128 times the MBC, respectively. Both CPFX and LVFX eradicated biofilm bacteria completely by 24 hours at a concentration 32 times the MBC. CONCLUSIONS: These results indicate that fluoroquinolones have the most potent bactericidal activity against the P. aeruginosa biofilm generated in urine.

Diagnosis and treatment of priapism: experience with 5 cases.

OBJECTIVES: Priapism is a rare disease, but needs early intervention and appropriate management. We present 5 cases, 2 of nonischemic high-flow priapism and 3 of ischemic low-flow priapism. METHODS: Focusing on the differential diagnosis of priapism between the nonischemic high-flow type and the ischemic low-flow type, we reviewed the medical records of 5 patients. RESULTS: Of the examinations carried out, cavernosography, blood gas analysis of cavernosal blood, color Doppler ultrasound, and internal pudendal arteriography were useful in differentiating the type of priapism. Complete detumescence of the penis in 2 cases of high-flow priapism and 3 cases of low-flow priapism was achieved by selective embolization with gelform and by glandular-cavernosal shunting, respectively. No recurrence was observed in any patient, and postoperative erectile function was preserved in 4 patients and is unknown in 1. CONCLUSIONS: These results indicate that angiographic studies provide the most reliable information for the differentiation of the type of priapism. However, color flow Doppler ultrasound and cavernosal blood gas determination can obviate the need for angiographic studies and are noninvasive. Although conservative treatment or even expectant management may be feasible with high-flow priapism, aggressive treatment should be carried out for low-flow priapism immediately after initial treatment fails to achieve detumescence of the penis. Selective embolization of the internal pudendal artery may be the treatment of choice for patients with high-flow priapism.

Intravesical instillation chemotherapy of adriamycin with or without verapamil for the treatment of superficial bladder cancer: the final results of a collaborative randomized trial.

A collaborative randomized clinical trial on the intravesical administration of Adriamycin (ADM) with or without verapamil (VR), a calcium-channel blocker, as chemotherapy of superficial bladder cancer (Ta, T1) was carried out at two universities, Okayama and Kagoshima, and their affiliated hospitals. Arm A consisted of ADM given at 50 mg/50 ml saline, and arm B consisted of ADM given at 50 mg/40 ml saline plus five ampules (25 mg/10 ml saline) of injectable VR. The drugs were instilled into the bladder for 3 consecutive days, and three such courses were given with a 4-day interval between each course for a total of nine instillations. A total of 96 patients (48 in arm A and 48 in arm B) were entered into this study. The two treatment groups showed no significant difference in background factors. Of the 40 evaluated arm-A patients, 24 (60.0%) showed a response (CR + PR), whereas 19 (48.7%) of the 39 patients in arm B responded. The difference between these response rates was not statistically significant. As for adverse reactions to the intravesical chemotherapy, local inflammatory symptoms were observed in half of the patients, although no systemic reaction was observed. No significant difference was found between arm A and arm B, except for urinary turbidity. In conclusion, at the dose employed in the present clinical trial, there was no clear enhancement of the effect of ADM combined with VR in patients with superficial bladder cancer. Further clinical studies are required to determine the optimal doses of ADM and VR for their combination in intravesical chemotherapy.

Intravesical instillation of adriamycin in the presence or absence of verapamil for the treatment of superficial bladder cancer: preliminary report of a collaborative study.

A case-controlled collaborative study on the intravesical administration of Adriamycin in the presence or absence of verapamil, a calcium-channel blocker, as chemotherapy of superficial bladder cancer was carried out at two universities, Okayama and Kagoshima, and their affiliated hospitals. Although little is known about the expression of P-glycoprotein in superficial bladder cancer, it may be a cause of multidrug resistance (MDR). Verapamil was used as an inhibitor of P-glycoprotein. Arm A consisted of Adriamycin given at 50 mg/50 ml saline, and arm B constituted Adriamycin given at 50 mg/40 ml saline plus 5 ampules (10 ml) of injectable verapamil. The drugs were instilled into the bladder for 3 consecutive days in each of 3 consecutive weeks for a total of 9 instillations. No significant difference in antitumor effects was observed between arm A and arm B. Recurrent tumors responded better than did primary tumors to both arm-A and arm-B treatments (P = 0.012). In both treatment arms, significant differences (P = 0.031) in the response rate were found between tumors with diameters of less than 1 cm and those measuring 1-3 cm in diameter. Although the number of evaluable patients was limited, recurrent subjects who had previously received Adriamycin instillations responded in both treatment arms.