Peptidylarginine deiminase is involved in maintaining the cornified oral mucosa of rats.

BACKGROUND AND OBJECTIVE: Epithelial cells derived from different regions exhibit marked differences in their differentiation capacity, allowing them to provide a suitable protective barrier. We aimed to clarify the role of peptidylarginine deiminase (PAD) in modifying the key epidermal proteins filaggrin (FLG) and keratin 1 (K1) during stratification of the rat palate and buccal mucosa. MATERIAL AND METHODS: We performed immunofluorescence, immunoblotting, PAD activity assays and 2-dimensional electrophoresis, and developed an organotypic culture model. RESULTS: PAD1 expression was highest in the palate, whereas PAD2, PAD3 and PAD4 expression was highest in the skin, suggesting the tissue-specific expression of PAD isozymes that leads to differences in calcium dependency. Immunoblotting showed that the FLG monomer, as well as its degradation products and precursor (proFLG), were most abundantly expressed in the skin but had low expression in the palate, whereas only faint proFLG expression was detected in the buccal mucosa. FLG and K1 were colocalized with PAD1 and were likely to be citrullinated in the cornified layers of the skin; this colocalization was not detected on the palatal surface, and dot-like presence of proFLG that might be citrullinated and that of PAD1 were found in the granules of the palate. Organotypic models derived from the rat palate revealed that PAD inhibition reduced the breakdown of FLG, increased its association with K1 together with epithelial compaction, and decreased permeability in a dye permeability assay. Conversely, PAD stimulation had the opposite effects. CONCLUSION: Citrullination is likely a protein modification that plays an important role in maintaining the structure and function of oral cornified mucosa in a way that is distinctly different from that of the skin.

Risk of haemolytic uraemic syndrome caused by shiga-toxin-producing Escherichia coli infection in adult women in Japan.

Shiga-toxin-producing Escherichia coli (STEC) infections usually cause haemolytic uraemic syndrome (HUS) equally in male and female children. This study investigated the localization of globotriaosylceramide (Gb3) in human brain and kidney tissues removed from forensic autopsy cases in Japan. A fatal case was used as a positive control in an outbreak of diarrhoeal disease caused by STEC O157:H7 in a kindergarten in Urawa in 1990. Positive immunodetection of Gb3 was significantly more frequent in female than in male distal and collecting renal tubules. To correlate this finding with a clinical outcome, a retrospective analysis of the predictors of renal failure in the 162 patients of two outbreaks in Japan was performed: one in Tochigi in 2002 and the other in Kagawa Prefecture in 2005. This study concludes renal failure, including HUS, was significantly associated with female sex, and the odds ratio was 4·06 compared to male patients in the two outbreaks. From 2006 to 2009 in Japan, the risk factor of HUS associated with STEC infection was analysed. The number of males and females and the proportion of females who developed HUS were calculated by age and year from 2006 to 2009. In 2006, 2007 and 2009 in adults aged >20 years, adult women were significantly more at risk of developing HUS in Japan.

Complete remission of recurrent and refractory ovarian cancers using weekly administration of bevacizumab and gemcitabine/oxaliplatin: report of two cases.

BACKGROUND: A combination therapy with gemcitabine and oxaliplatin (GEMOX) yielded a moderate activity in platinum-resistant ovarian cancers; however, frequent severe toxicities, such as thrombocytopenia and neurotoxicity, were observed. A certain modification of schedule might therefore facilitate the clinical application of the regimen. The authors report two cases that achieved complete response to a weekly administration of bevacizumab and GEMOX. MATERIALS AND METHODS: Two patients with platinum-resistant recurrent ovarian cancers received a weekly regimen of GEMOX with bevacizumab: 2 mg/kg of bevacizumab, 300 mg/m2 of gemcitabine, and 30 mg/m2 of oxaliplatin, three weeks on and one week off, Q4 weeks. Complete remission was observed after three to four courses of therapy. Hematologic and non-hematologic toxicities more than grade 2 were not observed during chemotherapy. The patients are now without tumor progression more than 12 months after initiation of therapy. CONCLUSION: Weekly administration of bevacizumab and GEMOX had potential activity in recurrent and refractory ovarian carcinomas. These findings warrant necessity of further trial in such clinical settings.

Normal serum CA125 half-life and normal serum nadir CA125 level in patients with ovarian cancers.

The normal serum CA125 half-life and distribution of the normal serum nadir CA125 value in patients with epithelial ovarian carcinoma (EOC) have not been determined yet. Among patients with EOC, 41 patients met the inclusion criteria of the present study: the patients that underwent complete cytoreductive surgery and six cycles of platinum-containing chemotherapy, and who had no recurrent disease more than five years. Serum CA125 half-life (T1/2) during primary surgery and primary chemotherapy was calculated and serum nadir CA125 level was evaluated by logarithmic-transformed serum CA125. Median value of nadir CA125 was 7 U/ml (range 3-20 U/ml), and the mean ln (serum nadir CA125) was 1.96 +/- 0.45. Mean T1/2 was 10.4 days in all patients, and T1/2 value was associated with the preoperative serum levels of CA125. Predicted slope of CA125 regression curve was also influenced by the preoperative CA125 value. The present study provides fundamental information with regard to normal half-life time and normal nadir of CA125 in EOC patients.

Olmesartan, a novel angiotensin II type 1 receptor antagonist, reduces severity of atherosclerosis in apolipoprotein E deficient mice associated with reducing superoxide production.

BACKGROUND AND AIM: Oxidative stress may play an important role in the development of atherosclerosis. Some angiotensin II type 1 (AT(1)) receptor antagonists have the capacity of reducing oxidative stress in addition to the hemodynamic actions. Accordingly, we assessed the hypothesis that olmesartan, a novel AT(1) receptor antagonist, reduced the severity of atherosclerosis in apolipoprotein (apo) E-deficient mice associated with reducing oxidative stress. METHODS AND RESULTS: Atherosclerosis was induced in apo E-deficient mice fed a high fat diet. Mice were intraperitoneally treated with an injection of olmesartan (1mg/kg/day) daily over 8 weeks, and were compared with the untreated controls. Blood pressure was not changed significantly by the olmesartan treatment. Fatty streak plaque developed in apo E-deficient mice, and was suppressed in mice that received olmesartan. In addition, olmesartan reduced not only superoxide production but the overload of oxidative stress in aortic walls. There were no significant differences in serum lipid levels between olmesartan-treated and -untreated groups. In vitro study showed that both olmesartan and its active metabolite RNH-6270, an enantiomer of olmesartan, suppressed interferon-γ, macrophage inflammatory protein-2, and thioredoxin (a marker of oxidative stress) concentrations in cultured cells. CONCLUSION: Olmesartan may suppress atherosclerosis via reducing not only superoxide production but also the overload of oxidative stress in this animal model.

Junctional adhesion molecule (JAM) binds to PAR-3: a possible mechanism for the recruitment of PAR-3 to tight junctions.

At tight junctions (TJs), claudins with four transmembrane domains are incorporated into TJ strands. Junctional adhesion molecule (JAM), which belongs to the immunoglobulin superfamily, is also localized at TJs, but it remains unclear how JAM is integrated into TJs. Immunoreplica electron microscopy revealed that JAM showed an intimate spatial relationship with TJ strands in epithelial cells. In L fibroblasts expressing exogenous JAM, JAM was concentrated at cell-cell adhesion sites, where there were no strand-like structures, but rather characteristic membrane domains free of intramembranous particles were detected. These domains were specifically labeled with anti-JAM polyclonal antibody, suggesting that JAM forms planar aggregates through their lateral self-association. Immunofluorescence microscopy and in vitro binding assays revealed that ZO-1 directly binds to the COOH termini of claudins and JAM at its PDZ1 and PDZ3 domains, respectively. Furthermore, another PDZ-containing polarity-related protein, PAR-3, was directly bound to the COOH terminus of JAM, but not to that of claudins. These findings led to a molecular architectural model for TJs: small aggregates of JAM are tethered to claudin-based strands through ZO-1, and these JAM aggregates recruit PAR-3 to TJs. We also discuss the importance of this model from the perspective of the general molecular mechanisms behind the recruitment of PAR proteins to plasma membranes.

Inoue Stent-Graft Implantation for Thoracoabdominal Aortic Aneurysm Involving the Visceral Arteries.

Purpose. To assess the efficacy of the Inoue stent-graft placement for thoracoabdominal aortic aneurysm (TAAA).Methods. Patients with TAAA underwent Inoue stent-graft placement with single branched stent-graft in 4 patients,straight graft in 3 patients and double branched stent-graft in 1 patient. Half the patients required additional open surgical revascularizations of involved visceral arteries (Hybrid procedures).Results. Stent-grafts were deployed successfully in all patients. One patient with Hybrid procedure developed major complications,required haemodialysis and died in hospital. In another patient the post-operative CT scan demonstrated a type I endoleak, but this had resolved by 3 months.Conclusion. Inoue stent-grafting for TAAA with or without adjunctive open surgical revascularization is feasible.

Low response rate of second-line chemotherapy for recurrent or refractory clear cell carcinoma of the ovary: a retrospective Japan Clear Cell Carcinoma Study.

Clear cell carcinoma (CCC) of the ovary has been recognized to show resistance to anticancer agents in the first-line chemotherapy. Our aim was to evaluate the effect of second-line chemotherapy in a retrospective study. A total of 75 patients diagnosed with CCC and treated between 1992 and 2002 in collaborating hospitals were reviewed. Criteria for the patients' enrollment were 1) diagnosis of pure-type CCC at the initial operation, 2) treatment after one systemic postoperative chemotherapy, 3) measurable recurrent or refractory tumor, 4) at least two cycles of second-line chemotherapy and assessable for the response, and 5) adequate clinical information. Regimens of first-line chemotherapy were conventional platinum-based therapy in 33 cases, paclitaxel plus platinum in 24 cases, irinotecan plus platinum in 9 cases, and irinotecan plus mitomycin C in 7 cases. Treatment-free periods were more than 6 months in 24 cases (group A) and less than 6 months in 51 cases (group B). In group A, response was observed in two cases (8%): one with conventional platinum therapy and another with irinotecan plus platinum. In group B, three cases (6%) responded: two with platinum plus etoposide and one case with irinotecan plus platinum. Median overall survival was 16 months in group A and 7 months in group B (P = 0.04). These findings suggest recurrent or resistant CCC is extremely chemoresistant, and there is only small benefit of long treatment-free period in CCC patients. Another strategy including molecular-targeting therapy is warranted for the treatment of recurrent or refractory CCC.

Induction of continuous ambulatory peritoneal dialysis after retroperitoneoscopic nephrectomy.

Induction of continuous ambulatory peritoneal dialysis (CAPD) as treatment of end-stage renal disease is difficult for patients requiring nephrectomy with traditional surgery, and usually hemodialysis is selected for these patients. In a 61-year-old woman with end-stage renal failure a left renal tumor was diagnosed by abdominal ultrasonography, enhanced computed tomography and magnetic resonance imaging. Following an urology consultation, we decided to perform left kidney nephrectomy. We estimated that she had to undergo dialysis permanently after nephrectomy. She desired to be treated by CAPD, however, we decided after allowing for a postoperative period for complete healing of the peritoneum to avoid complications. This is why during the interim period between surgery and induction of CAPD she underwent hemodialysis (HD) in a local outpatient HD center and in our hospital. We selected a retroperitoneoscopic approach for nephrectomy. Pathology evaluation revealed a renal cell carcinoma. 4 months after nephrectomy, CAPD catheter implantation was performed by using laparoscopy and CAPD was started. At the present time, the patient is doing well on CAPD. To our knowledge, there are no clear indications regarding initiation of peritoneal dialysis after nephrectomy. The retroperitoneoscopic approach for nephrectomy allows for initiation of peritoneal dialysis after nephrectomy within a relative short postoperative period.

Feedback regulation of 3-hydroxy-3-methylglutaryl coenzyme A reductase in livers of mice treated with mevinolin, a competitive inhibitor of the reductase.

Compactin (ML-236B) and the related compound, mevinolin, are competitive inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG CoA reductase), the rate-controlling enzyme in cholesterol synthesis. Previous studies have shown that administration of compactin to cultured cells elicits a compensatory increase in the amount of HMG CoA reductase in the cells. A similar increase in HMG CoA reductase has been reported in livers of rats and mice that have been treated with compactin. In this study, we explore the mechanism for the mevinolin-mediated increase in hepatic HMG CoA reductase in mice that have been fed a control diet and a 2% cholesterol diet. Administration of mevinolin to mice on a control diet produced a 6- to 10-fold increase in the amount of HMG CoA reductase in liver microsomes. When mice were fed the cholesterol-enriched diet, cholesterol accumulated in the liver and HMG CoA reductase declined by 90%. The administration of mevinolin to cholesterol-fed mice produced a three to eightfold increase in HMG CoA reductase. Despite the abundant amount of cholesterol that was already present in the livers of the mevinolin-treated, cholesterol-fed animals, their elevated HMG CoA reductase could be rapidly suppressed by the subcutaneous injection of small amounts of mevalonate, the product of HMG CoA reductase. These data are compatible with the existence in mouse liver of a multivalent feedback regulatory mechanism for HMG CoA reductase in which suppression of the enzyme requires both a sterol and a nonsterol substance derived from mevalonate. By blocking mevalonate synthesis, mevinolin activates this regulatory mechanism, and this in turn causes an increase in hepatic HMG CoA reductase. The ability to suppress the elevated HMG CoA reductase with mevalonate may prove useful in potentiating the effectiveness of mevinolin as a hypocholesterolemic agent.

Stimulation of cholesteryl ester synthesis in mouse peritoneal macrophages by cholesterol-rich very low density lipoproteins from the Watanabe heritable hyperlipidemic rabbit, an animal model of familial hypercholesterolemia.

Cholesterol-rich very low density lipoproteins (VLDL) from the homozygous Watanabe heritable hyperlipidemic (WHHL) rabbit induced marked cholesteryl ester accumulation in mouse peritoneal macrophages. This WHHL rabbit, an animal model of human familial hypercholesterolemia, has severe hypercholesterolemia, cutaneous xanthomas, and fulminant atherosclerosis due to the deficiency of the low density lipoprotein (LDL) receptor. When incubated with mouse peritoneal macrophages, the VLDL from WHHL rabbit (WHHL-VLDL) stimulated cholesteryl [14C]oleate synthesis 124-fold more than did VLDL from the normal Japanese White rabbit (control-VLDL). The enhancement in cholesteryl ester synthesis and accumulation of WHHL-VLDL was due to the presence of a high affinity binding receptor site on the macrophage cell surface that mediated the uptake and lysosomal degradation of WHHL-VLDL. Competition studies showed that the uptake and degradation of 125I-WHHL-VLDL was inhibited by unlabeled excess WHHL-VLDL and beta-migrating VLDL (beta-VLDL), but not LDL. Furthermore, the degradation of WHHL-VLDL was not blocked by either fucoidin, polyinosinic acid, or polyguanylic acid, potent inhibitors of the acetylated (acetyl)-LDL binding site, or by acetyl-LDL. These results suggest that macrophages possess a high affinity receptor that recognizes the cholesterol-rich VLDL present in the plasma of the WHHL rabbit and that the receptor which mediates ingestion of WHHL-VLDL seems to be the same as that for beta-VLDL and leads to cholesteryl ester deposition within macrophages. Thus the uptake of the cholesterol-rich VLDL from the WHHL rabbit by macrophages in vivo may play a significant role in the pathogenesis of atherosclerosis in the WHHL rabbit.

Stimulated arachidonate metabolism during foam cell transformation of mouse peritoneal macrophages with oxidized low density lipoprotein.

Changes in arachidonate metabolism were examined in mouse peritoneal macrophages incubated with various types of lipoproteins. Oxidized low density lipoprotein (LDL) was incorporated by macrophages and stimulated macrophage prostaglandin E2 (PGE2) and leukotriene C4 syntheses, respectively, 10.8- and 10.7-fold higher than by the control. Production of 6-keto-PGF1 alpha, a stable metabolite of prostacyclin, was also stimulated. No stimulation was found with native LDL, which was minimally incorporated by the cells. Acetylated LDL and beta-migrating very low density lipoprotein (beta-VLDL), though incorporated more efficiently than oxidized LDL, also had no stimulatory effect. When oxidized LDL was separated into the lipoprotein-lipid peroxide complex and free lipid peroxides, most of the stimulatory activity was found in the former fraction, indicating that stimulation of arachidonate metabolism in the cell is associated with uptake of the lipoprotein-lipid peroxide complex. These results suggest that peroxidative modification of LDL could contribute to the progression of atheroma by stimulating arachidonate metabolism during incorporation into macrophages.

A trilogy of primary prevention statin trials. Panel discussion.

Presented is a report of a panel discussion held as part of the ISA 2006 Sankyo Forum titled "A Trilogy of Primary Prevention Statin Trials--The Impact of These Landmark Studies on Clinical Practice," Rome, Italy, June 2006. The themes of the panel discussion were the design features of three trials, WOSCOPS, AFCAPS/TexCAPS, and Japan's MEGA Study; comparison of their primary endpoints; and the implications of their results. Among the topics discussed by the panel of experts from Japan, USA, and UK were observations on the benefits associated with pravastatin at low dose as demonstrated in the MEGA Study as well as that study's implications for women, who represented the majority of subjects. Several suggestions were put forth to explain how the low dose used in MEGA elicited similar LDL-C reductions to those observed in WOSCOPS and AFCAPS/TexCAPS at higher doses including the body size hypothesis, genetic variation, and statin-diet interaction. It was felt that in Japan, the current guidelines are adequate; there seemed no merit in radically reducing LDL-C levels since in the Japanese population the risk is generally low. Japanese physicians tend to use small doses of statin and believe that these are effective in lowering cholesterol sufficiently with few side effects and encourage good compliance.

Efficient two-step photocarrier generation in bias-controlled InAs/GaAs quantum dot superlattice intermediate-band solar cells.

We studied the effects of the internal electric field on two-step photocarrier generation in InAs/GaAs quantum dot superlattice (QDSL) intermediate-band solar cells (IBSCs). The external quantum efficiency of QDSL-IBSCs was measured as a function of the internal electric field intensity, and compared with theoretical calculations accounting for interband and intersubband photoexcitations. The extra photocurrent caused by the two-step photoexcitation was maximal for a reversely biased electric field, while the current generated by the interband photoexcitation increased monotonically with increasing electric field intensity. The internal electric field in solar cells separated photogenerated electrons and holes in the superlattice (SL) miniband that played the role of an intermediate band, and the electron lifetime was extended to the microsecond scale, which improved the intersubband transition strength, therefore increasing the two-step photocurrent. There was a trade-off relation between the carrier separation enhancing the two-step photoexcitation and the electric-field-induced carrier escape from QDSLs. These results validate that long-lifetime electrons are key to maximising the two-step photocarrier generation in QDSL-IBSCs.

Galanin-like peptide promotes feeding behaviour via activation of orexinergic neurones in the rat lateral hypothalamus.

Galanin-like peptide (GALP) is produced in neurones in the hypothalamic arcuate nucleus and is implicated in the neural control of feeding behaviour. Previously, we have reported that GALP immunoreactive fibres were in direct contact with orexin/hypocretin immunoreactive neurones in the rat lateral hypothalamus using double-immunofluorescence. Centrally administered GALP is known to stimulate feeding behaviour. However, the target neurones of this action have not been clarified. The present study aimed to determine features of the GALP-mediated neuronal feeding pathway in rat. Accordingly, at the ultrastructural level, GALP-immunoreactive axon terminals were found to make synapses on orexin/hypocretin immunoreactive cell bodies and dendritic processes in the lateral hypothalamus. c-Fos immunoreactivity was expressed in orexin/hypocretin-immunoreactive neurones but not in melanin concentrating hormone-immunoreactive neurones in the lateral hypothalamus at 90 min after the application of GALP by i.c.v. infusion. Furthermore, to determine whether GALP regulates feeding behaviour via orexin/hypocretin neurones, the feeding behaviour of rats was studied following GALP i.c.v. injection with or without anti-orexin A and B immunoglobulin (IgG) pretreatment. The anti-orexin IgGs markedly inhibited GALP-induced hyperphagia. These results suggest that orexin/hypocretin-containing neurones in the lateral hypothalamus are targeted by GALP, and that GALP-induced hyperphagia is mediated via orexin/hypocretin neurones in the rat hypothalamus.

A novel snail-related transcription factor Smuc regulates basic helix-loop-helix transcription factor activities via specific E-box motifs.

Snail family proteins are zinc finger transcriptional regulators first identified in Drosophila which play critical roles in cell fate determination. We identified a novel Snail -related gene from murine skeletalmusclecells designated Smuc. Northern blot analysis showed that Smuc was highly expressed in skeletal muscle and thymus. Smuc contains five putative DNA-binding zinc finger domains in its C-terminal half. In electrophoretic mobility shift assays, recombinant zinc finger domains of Smuc specifically bound to CAGGTG and CACCTG E-box motifs (CANNTG). Because basic helix-loop-helix transcription factors (bHLH) bind to the same E-box sequences, we examined whether Smuc competes with the myogenic bHLH factor MyoD for DNA binding. Smuc inhibited the binding of a MyoD-E12 complex to the CACCTG E-box sequence in a dose-dependent manner and suppressed the transcriptional activity of MyoD-E12. When heterologously targeted to the thymidine kinase promoter as fusion proteins with the GAL4 DNA-binding domain, the non-zinc finger domain of Smuc acted as a transcriptional repressor. Furthermore, overexpression of Smuc in myoblasts repressed transactivation of muscle differentiation marker Troponin T. Thus, Smuc might regulate bHLH transcription factors by zinc finger domains competing for E-box binding, and non-zinc finger repressor domains might also confer transcriptional repression to control differentiation processes.

Inhibition of human ovarian cancer cell growth in vitro and in nude mice by prostaglandin D2.

In vitro and in vivo effects of prostaglandin D2 on human ovarian tumor growth were examined by using a cell line, designated HR, derived from ascites of a patient with serous cystadenocarcinoma of the ovary. The HR cell proliferation in vitro was dose dependently inhibited between concentrations of 0.1 and 4.0 micrograms of prostaglandin D2 per ml. From results of 51Cr release assays and trypan blue dye exclusion tests the inhibitory effect seemed to result from a direct cytotoxic effect by prostaglandin D2. All DNA, RNA, and protein syntheses by the HR cells were also inhibited in a dose-dependent manner with exposure time of 48 h to prostaglandin D2. When 5 X 10(5) HR cells were inoculated to nude mice, the 50% survival time of them in untreated groups was 52 days after inoculation. Although 4 mg of prostaglandin D2 per kg caused inhibition of the tumor growth, a significant prolongation of the survival time was not observed. On the other hand, the 50% survival time of nude mice treated with 12 mg of prostaglandin D2 per kg was significantly (P less than 0.05) prolonged to 67 days, in addition to a significant inhibition of the tumor growth.

Establishment of a human ovarian cancer cell line capable of forming ascites in nude mice and effects of tranexamic acid on cell proliferation and ascites formation.

The present study was designed to obtain an experimental tumor model as similar as possible to human ovarian cancer which often had a large amount of ascites and to assess the therapeutic value of tranexamic acid. Human tumor cell lines which form ascites in nude mice were established from ascites of patient with serous cystadenocarcinoma of the ovary. Two cloned cell lines designated HRA and HR-1 were obtained from the parent cell line designated HR. All of these cultured cell lines had about 2.5-3.5 times higher lactate dehydrogenase activities than the original tumor. The original tumor and the tumor grown in nude mice had all 5 bands of lactate dehydrogenase isoenzymes, while all cultured cell lines had only a marked lactate dehydrogenase-3 in addition to a faint lactate dehydrogenase-2. Modal chromosome numbers of HR cells ranged from 50-76, while that of HRA cells ranged widely from 40-140. The DNA histograms of HR and HRA cells were similar to each other, showing predominant G1 and S phases. Although these cell lines had ability to produce ascites in the nude mice when the cells were inoculated i.p., the HRA cell inoculation made ascites most rapidly and brought about the shortest median survival (39 days). The proliferations of all three cell lines were dose-dependently inhibited by tranexamic acid. However, the concentration of this drug required for 50% inhibition of the proliferation of HRA cells was about one-half of that of HR and HR-1 cells. In addition, i.p. injections of tranexamic acid to nude mice treated with cisplatin resulted in a significant inhibition of the ascites formation and prolongation of 50% survival.

Enhancement of antineoplastic effects of cisplatin by calmodulin antagonists in nude mice bearing human ovarian carcinoma.

The present study was designed to potentiate the antineoplastic effects of cisplatin by combination with calmodulin antagonists [N-(6-amino-hexyl)-5-chloro-1-naphthalenesulfonamide (W-7) and N-(6-aminohexyl)-1-naphthalenesulfonamide (W-5)] in nude mice bearing human ovarian carcinoma. Tumor growth of nude mice treated with W-7 or W-5 combined with cisplatin was significantly inhibited, compared to that of nude mice treated with W-7 alone, W-5 alone, or cisplatin alone. Although treatment with cisplatin alone markedly inhibited lytic activity of spleen cells from tumor-bearing nude mice against the tumor cells, the inhibitory effect was eliminated by combination with W-7 or W-5. There was no significant difference in survival time among untreated, cisplatin-treated, W-7-treated, and W-5-treated groups. Only when cisplatin was followed by W-7 or W-5 was a significant enhancement by W-7 or W-5 of the antitumor effect of cisplatin observed with respect to inhibition of tumor growth as well as prolongation of survival time.

Immunological characterization and clinical implication of cobalamin binding protein in human gastric cancer.

Cobalamin (vitamin B12) binding protein was purified from gastric cancer extracts and from serum-free culture medium of cancer cell line KATOH-III. The molecular weight, determined by immunoprecipitation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, was 70,000 and the pI was 2.8 to 3.2. From biochemical and immunological properties, this cobalamin binding protein was considered to be an isoprotein of cobalamin R binder. Monoclonal antibodies were produced against saliva R and cobalamin binding protein in culture medium to study their antigenic determinants. Monoclonal antibody 55-D reacted to an epitope of peptide in both binders, whereas WK-1 and H-12 reacted to determinants of a carbohydrate moiety, including sialic acid, in cancer cell-derived binder. In addition, we carried out an enzyme-linked immunoassay and examined plasma levels of immunoreactive R binder in patients with gastric cancer (n = 72), benign gastrointestinal disease (n = 30), and healthy individuals (n = 40). Even in patients without liver metastasis, the level of immunoreactive R binder detected by monoclonal antibody H-12 was elevated in some patients and decreased after excision of the tumor. R binder was also elevated in cancer tissue extract. Immunoreactive binder was histochemically detected in the cytosol of cancer cells and metaplastic cells of the gastric mucosa. The present findings suggest that cobalamin R binder is de novo synthesized in gastric cancer cells and that its plasma level increases in some patients. This binding protein may be a useful diagnostic and therapeutic parameter.