Orphan nuclear receptor ROR alpha gene: isoform-specific spatiotemporal expression during postnatal development of brain

We analyzed expression of mouse orphan nuclear receptor ROR alpha during postnatal development of rodent brain. Using a riboprobe corresponding to the 3'-end of mROR alpha cDNA a peak of ROR alpha expression was observed at postnatal 16 day (P16) in the Purkinje cells of cerebellum, neurons of the thalamus and the olfactory bulb. The hippocampus was also shown to express ROR alpha with an earlier peak at P7. Expression in cell types other than the Purkinje cells appeared transient. On the other hand, when a probe to the 5'-end of mROR alpha cDNA was used, we observed patterns of ROR alpha expression that are different from those observed with the 3'-probe. No specific transcripts of ROR alpha were detected with the 5'-probe in the Purkinje cells until P16. Additionally, the relative level of the hybridization signals with the 5'-probe and the 3'-probe were different among the various brain regions. Together with the previous findings that ROR alpha comprises at least four isoforms which differ from one another in their N-terminal regions, these observations suggest that the spatiotemporal expression of ROR alpha is under isoform-specific regulation. The timing of its expression suggests that ROR alpha may be involved in regulation of postnatal maturation of specific classes of neurons.

Rapid progression of flat warts in a patient with malignant lymphoma after PBSCT

A 51-year-old man with non-Hodgkin's lymphoma in his third remission received autologous PBSCT. He had had a couple of flat warts on his right hand since admission, which showed no progression during conventional dose chemotherapy. On day 15 of PBSCT, however, the warts began to develop and spread to his forehead, face, neck and arms over several days. The diagnosis of flat warts was made and human papilloma virus type 3 was detected by PCR analysis. Severe immunosuppression associated with PBSCT may have caused this rapid and disseminated growth of flat warts.

Benzyl-alpha-GalNAc inhibits sialylation of O-glycosidic sugar chains on CD44 and enhances experimental metastatic capacity in B16BL6 melanoma cells

We examined the effect of benzyl-alpha-N-acetylgalactosamine (benzyl-alpha-GalNAc), which specifically inhibits the synthesis of O-linked oligosaccharides, on the expression of the peanut agglutinin (PNA)-binding sugar chains (Gal beta 1-3GalNAc) of CD44 and on its experimental metastatic ability in B16BL6 melanoma. Benzyl-alpha-GalNAc increased the PNA-binding, but not Concanavalin A (Con A), wheat germ agglutinin (WGA), and leukoagglutinating phytohemaagglutinin (L-PHA)-binding to the cell surface. Benzyl-alpha-GalNAc markedly increased the PNA-binding to CD44 by decreasing the sialylation of these sugar chains. The experimental metastatic ability of B16BL6 cells was enhanced in association with this modulation of the sugar chains. These findings suggested that unsialylated Gal beta 1-3GalNAc sugar chains on the cell surface and/or CD44 are involved in the metastatic process of B16BL6 melanoma cells. On the other hand, the known functions of CD44, such as adhesion to hyaluronate, fibronectin, collagen, and endothelial cells, as well as homotypic aggregation, were not affected by benzyl-alpha-GalNAc regardless of the enhancement of metastatic ability induced by this glycosylation inhibitor. CD44 might have other metastasis related functions that remain to be elucidated.

Increased numbers of macrophages in noninflamed gastroduodenal mucosa of patients with Crohn's disease

We investigated immunostained macrophages in the noninflamed mucosa of Crohn's disease patients. Biopsied specimens from endoscopically normal gastroduodenal mucosa of Crohn's disease, ulcerative colitis, and healthy control patients were studied. Sections were examined immunohistochemically using a monoclonal antibody specific for tissue macrophages (CD68). Immunostained mucosal macrophages in the second part of the duodenum, duodenal bulb, gastric antrum, and gastric body of the Crohn's disease group were more numerous than in the ulcerative colitis and control groups. The characteristic findings of Crohn's disease were aggregations, focal subepithelial dense accumulations, and infiltration throughout the mucosa of macrophages not accompanied by a lymphoid infiltrate. The number of macrophages in the gastroduodenal mucosa bore no relationship with the duration of symptoms, clinical activity, or affected site in the intestine. This suggests that the increased number of macrophages in noninflamed mucosa is a histological change characteristic for Crohn's disease that indicates a persistent latent abnormality involving the entire gastrointestinal tract.

G protein-coupled cholecystokinin-B/gastrin receptors are responsible for physiological cell growth of the stomach mucosa in vivo

Many peptide hormone and neurotransmitter receptors belonging to the seven membrane-spanning G protein-coupled receptor family have been shown to transmit ligand-dependent mitogenic signals in vitro. However, the physiological roles of the mitogenic activity through G protein-coupled receptors in vivo remain to be elucidated. Here we have generated G protein-coupled cholecystokinin (CCK)-B/gastrin receptor deficient-mice by gene targeting. The homozygous mice showed a remarkable atrophy of the gastric mucosa macroscopically, even in the presence of severe hypergastrinemia. The atrophy was due to a decrease in parietal cells and chromogranin A-positive enterochromaffin-like cells expressing the H+,K(+)-ATPase and histidine decarboxylase genes, respectively. Oral administration of a proton pump inhibitor, omeprazole, which induced hypertrophy of the gastric mucosa with hypergastrinemia in wild-type littermates, did not eliminate the gastric atrophy of the homozygotes. These results clearly demonstrated that the G protein-coupled CCK-B/gastrin receptor is essential for the physiological as well as pathological proliferation of gastric mucosal cells in vivo.

Preparation and reactions of myoglobin mutants bearing both proximal cysteine ligand and hydrophobic distal cavity: protein models for the active site of P-450

We have reported that H93C human myoglobin (Mb), in which proximal histidine (His93, F8) was replaced by cysteine, gave nearly identical spectroscopic features of P-450 [Adachi, S., Nagano, S., Ishimori, K., Watanabe, Y., Morishima, I., Egawa, T., Kitagawa, T., & Makino R. (1993) Biochemistry 32, 241-252]. More importantly, the thiolate ligand enhanced its oxygenation activities when supported by H2O2 due to the exclusive encouragement of heterolytic O-O bond cleavage of peroxides. While we have attributed the enhanced heterolysis to the electron donation from the thiolate ligand, possible participation of the distal histidine (H64, E7) in H93C Mb cannot be eliminated. In addition, the racemic product formation catalyzed by H93C Mb implied that its distal cavity could prevent substrates from accessing to the heme and the reactions may proceed other than by the P-450 type mechanism (ferryl oxygen transfer). In order to clarify whether the distal histidine is involved in the O-O bond cleavage step and to improve accessibility of substrates, the distal histidine of H93C Mb is replaced by smaller and nonpolar residues, glycine (H64G/H93C Mb) and valine (H64V/H93C Mb), by site-directed mutagenesis. Various spectroscopic studies on these double-mutated Mbs revealed the ligation of cysteine to the ferric heme as a thiolate form. In the reaction with cumene hydroperoxide, the anionic nature of the proximal cysteine in H64G/H93C and H64V/H93C Mbs was found to encourage the heterolytic O-O bond cleavage as observed for H93C Mb. The results clearly demonstrate that the distal histidine of H93C Mb is hardly involved in the O-O bond cleavage step and are in good agreement with the role of thiolate ligation for the formation of the reactive intermediate, equivalent to compound I, in the catalytic cycle of P-450 reactions. In the oxygenation of methyl p-tolyl sulfide, the ratios of ferryl oxygen transfer increased in H64G/H93C Mb (58%) and H64V/H93C Mb (78%) as compared to H93C Mb (53%). The increased ratios of ferryl oxygen transfer imply the active site of H64G/H93C and H64V/H93C Mbs being more accessible for substrates; however, the sulfoxidation by the ferric mutant Mbs/H2O2 system was much slower than that by H93C Mb. The poor activities of these mutant Mbs are attributed to the significantly discouraged binding of H2O2.

[Objective visual field measurement using "pupil perimetry"]

In an attempt to measure the visual field objectively, we developed a system of "Pupil Perimetry". An infrared pupillometry machine was linked to a Goldmann perimeter to record the visual field by mapping the change in the pupil area (mm2) at each target location within the field. We decreased the background intensity to 10Asb to get maximum pupil response. The target was exposed for 0.25 seconds with an intensity of 1,000 Asb. Pupil response was observed up to 90 degrees laterally and 60 degrees nasally across a meridian in normal subjects. Visual fields obtained from patients with homonymous hemianopsia, glaucoma and Leber's optic neuropathy were compatible with a field obtained by a Humphrey field analyzer (FHA) 30-2 program. Pupil perimetry is a useful tool for measuring the visual field objectively.

[Radical prostatectomy for localized prostate cancer]

We studied 81 patients who underwent radical prostatectomy for prostate cancer. Ten, 57 and 14 patients were clinically diagnosed with stage T1, T2 and T3, respectively. Pelvic lymph node dissection was performed prior to prostatectomy in all cases. The neurovascular bundle was preserved in 21 patients. Compared with pathological stage, the accuracy rate of clinical staging in T1, T2 and T3 was 40, 46 and 64% respectively. Approximately half of the patients clinically diagnosed with stage T2 were pT3. The positive rate of lymph node in pT2 and pT3 was 3.3 and 37% respectively, showing a marked difference between these two pathological stages. The 3-year non-recurrence rates were 89% in patients with pT2 and 79% in pT3. In the well differentiated carcinoma group, no patients had recurrence for up to 3 years. All of the patients with infiltration (INF) gamma showed recurrence within 3 years. Fifty-five patients had no problem on urination post-operatively, while the other 23 patients had a mild or moderate incontinence and the remaining 3 patients had a small urine stream. Regarding erectile potency, 4 out of 18 evaluable patients were potent.

Degenerative axonal swellings in the trigeminal ganglia of cattle

We examined the acidophilic oval structures which were frequently encountered in the trigeminal ganglia of cattle that clinically showed trigeminal disturbance. Histopathologically, these structures were composed of numerous fine granules and were generally located near the neuronal cell bodies. They were demonstrated in silver preparations and, using neuron-specific enolase, tau and ubiquitin antibodies. Electron microscopy revealed an accumulation of large membranous vesicles thought to be derived from the smooth endoplasmic reticulum of axons, a few degenerative mitochondria and non-membrane-bound osmiophilic debris. Such pathological alterations were consistent with degenerative axonal changes or enlargements, although the pathogenesis was not clear. It should be emphasized that such axonal degeneration is frequently observed as a nonspecific reaction in the trigeminal ganglia in various diseases that cause trigeminal failure in cattle.

Paracrine stimulation of cell growth by cholecystokinin/gastrin through cholecystokinin-B receptor on GH3 cells in vitro

Cholecystokinin (CCK) is detected in pituitary tumors but its role remains unknown. On the hypothesis that CCK may facilitate the cell growth in pituitary tumors, we have examined the effect of CCK on cell growth using a rat pituitary tumor cell line, GH3, cultured in a serum-free, chemically defined medium. Addition of sulfated CCK-(26-33) (CCK-8) in two different concentrations (0.5 approximately 1 nM) caused a significant increase in the number of GH3 cells. The antagonist (1 microM) for CCK-B receptor, but not CCK-A receptor, significantly inhibited the number of GH3 cells. Northern blot analysis revealed a significant expression of CCK-B receptor mRNA in GH3 cells, but not in normal rat pituitary glands. In addition, immunoreactive CCK/gastrin was detected by RIA in the GH3 cell extracts as well as the serum-free culture medium. In GH3 cell extracts, both CCK-8 and gastrin like peptides were identified by gel chromatography. These findings provided the first evidence for an autocrine/paracrine role of CCK and gastrin on stimulation of GH3 cell growth through the CCK-B receptor.

Natural history of superficial depressed colorectal cancer: retrospective radiographic and histologic analysis

PURPOSE

To characterize the growth and developmental changes of superficial depressed colon cancer by using retrospective radiographic and histologic data.

MATERIALS AND METHODS

In a retrospective study, the radiographs in patients with nine superficial depressed and those with 12 elevated (sessile or semipedunculated) colon cancers were analyzed.

RESULTS

The initial superficial depressed lesions were 11.7 mm (mean) in diameter and took an average of 32.3 months to double in size. The initial elevated lesions were 15.7 mm (mean) in diameter and took an average of 8.6 months to double in size. The initial size of the former was not statistically significantly different from that of the latter; however, the doubling time of the superficial depressed cancers was statistically significantly slower than that of the elevated cancers. Superficial depressed cancers did not have concomitant adenomatous components, did not develop rapidly into advanced cancer, and did not change greatly from their original configuration; their growth rate was rather slow. Histologically, superficial depressed cancers showed a nonpolypoid growth pattern.

CONCLUSION

Superficial depressed cancer develops more slowly than does elevated cancer, and this development follows a nonpolypoid growth pattern.

Autocrine loop through cholecystokinin-B/gastrin receptors involved in growth of human leukemia cells

The cholecystokinin (CCK)-B/gastrin receptor binds two brain-gut hormones, CCK and gastrin, with high affinities. These peptides have a trophic effect on gastrointestinal cells expressing the receptor in vivo as well as in vitro. Recently, this receptor mRNA was reported to be expressed in immunocytes localized in the lamina propria of normal rat stomach mucosa. Here, we studied the receptor expression in human hematopoietic cells in order to determine whether they play a role in cell growth. The CCK-B/gastrin receptor mRNA was detectable in the polymorphonuclear (PMN) cells but not in the mononuclear cells of normal peripheral white blood cells by reverse transcription-polymerase chain reaction. The receptor transcript was, however, expressed in human leukemia cell lines (14 of 18 cell lines tested) derived from not only myeloid, but also T- and B- lymphoid lineages. The CCK-B/gastrin receptors on several leukemia cell lines were shown to be biologically active by demonstrating ligand-dependent cell proliferation in serum-deprived medium. Interestingly, a human CCK-B/gastrin receptor specific antagonist, YM022, but not its stereotype isoform, selectively inhibited the DNA synthesis of THP-1, MOLT-16, MOLT-14, and CCRF-CEM in the absence of exogenous peptide ligands. Further investigation revealed that these leukemia cell lines and normal PMN cells also expressed gastrin mRNA. These results suggest that growth of human leukemia cells is promoted by an autocrine mechanism through the CCK-B/gastrin receptors.

Purification and characterization of bitiscetin, a novel von Willebrand factor modulator protein from Bitis arietans snake venom

We have screened 20 snake venoms and purified a novel snake venom protein, named bitiscetin, from Bitis arietans venom that specifically binds to human von Willebrand factor (vWF) and induces platelet agglutination. Bitiscetin showed a heterodimeric structure composed of disulfide-linked alpha (16kDa) and beta (13kDa) subunits on SDS-PAGE and showed a basic nature with pI value of 9.1, in contrast to botrocetin (pI 4.6), a vWF modulator isolated from another snake (Bothrops jararaca) venom. Bitiscetin-induced platelet agglutination was dependent on vWF and platelet membrane glycoprotein (GP) Ib, but not on Ca2+ and GPIIb/IIIa. vWF bound to bitiscetin but not to botrocetin electroblotted to a PVDF membrane after SDS-PAGE and this binding was diminished after reduction of disulfide bonds of bitiscetin. Bitiscetin did not cross-react to anti-botrocetin monoclonal antibodies. These results suggest that bitiscetin directly interacts with vWF and requires the protein conformation for its interaction as well as botrocetin, but its interaction manner with vWF appears to be different from that of botrocetin.

Status of the coagulation and fibrinolytic systems in ovarian hyperstimulation syndrome

OBJECTIVE

To elucidate characteristic changes of plasma hemostatic markers in ovarian hyperstimulation syndrome (OHSS) cycles.

DESIGN

Prospective study.

SETTING

The IVF-ET program of the Department of Obstetrics and Gynecology, The University of Akita, School of Medicine.

PATIENTS

Forty cycles of 40 IVF patients, including 12 cycles in which a severe form of OHSS occurred.

INTERVENTIONS

Blood samples were taken during IVF treatment to determine the levels of blood markers that reflect activation of the coagulation and fibrinolytic systems.

MAIN OUTCOME MEASURES

Thrombin-antithrombin III complexes, plasmin-alpha 2 antiplasmin complexes, and other hemostatic markers related to the coagulation and fibrinolytic system activation.

RESULTS

In the OHSS cycles, the levels of thrombin-antithrombin III and plasmin-alpha 2 antiplasmin complexes in the plasma began to rise within a few days after hCG administration and demonstrated significantly higher levels during the midluteal phase. In OHSS cycles with pregnancy, elevation of these markers continued for > or = 3 weeks after the onset of disease. There were some characteristic changes in OHSS cycles in other hemostatic markers, such as a decrease in the levels of antithrombin III and prekallikrein and shortened activated partial thromboplastin time.

CONCLUSION

These data demonstrate the status of the coagulation and fibrinolytic systems in OHSS cycles and provide insight into the mechanism of activation in the hemostatic system.

[Treatment results for unselected patients with acute myelogenous leukemia. During a 10-year period, August 1984 to July 1994]

In order to analyse the clinical characteristics and outcome in acute myelogenous leukemia, 129 consecutive adult patients admitted to our hospital over a 10-year period, from August 1984 to July 1994, were studied. Their median age was 51 years, 17 (13.2%) of them had antecedent myelodysplastic syndrome (MDS) and 9 (7.0%) had secondary leukemia. Seventy-eight patients (60.5%) were considered eligible for cure-oriented intensive chemotherapy. Forty-four patients were ineligible of one or more of the following; age over 70, antecedent MDS or secondary leukemia. Additional 7 patients were excluded due to concurrent severe diseases. The median survival of the 129 patients was 441 days with an actuarial 5-year survival of 28.6 +/- 4.4%, and the disease-free survival (DFS) decreased with the increasing age of the patient. In 78 patients who were eligible for intensive chemotherapy, complete remission was achieved in 84.6% and overall DFS was 41.1 +/- 5.9% at 5 years, and their survival was longer than that of ineligible patients. It was suggested that considerable selection of patients, for example, due to old age, already existed before visiting our hospital. Analysis of clinical data of unselected patients might enable the development of a rational approach to the management of elderly patients.

The importance of the real-time fluoroscopic intraoperative direct cholangiogram in the laparoscopic cholecystectomy using a new instrument

BACKGROUND/AIMS

Laparoscopic cholecystectomy (LC) has become an accepted standard operative technique for gallstone treatment worldwide. On the other hand, complications, such as bile duct injuries, have been reported recently with the expansion of indication for LC. Intraoperative cholangiogram (IOC), to minimize the risk of bile duct injury, is now considered to be essential for safe LC. There are disadvantages to IOC such as increased operating time, the possibility of bile duct injury and the difficulties of manipulation.

MATERIAL AND METHODS

We have developed a method for real-time fluoroscopic cholangiograms using a new instrument designed by our group for safe LC. First, a round-tip stylet is inserted through a sheath to coax it gently through the spiral valves of the cystic duct. Secondly, the stylet is removed and the cholangiogram catheter is inserted smoothly. Digital C-arm fluoroscopy provides "real-time" imaging of biliary tree. As a result, we became able to obtain a clear cholangiogram easily in a very short time.

RESULTS

In the first 136 patients, direct cholangiograms were attempted in 106 cases and successfully completed in 102 cases (96.2%).

CONCLUSION

With the development of real-time fluoroscopic intraoperative direct cholangiogram, we are able to cope with bile duct injuries and anomalies, and unsuspected bile duct stones.

Intrinsic signaling function of APP as a novel target of three V642 mutations linked to familial Alzheimer's disease

APP695 is a transmembrane precursor of Abeta amyloid. In familial Alzheimer's disease (FAD), three mutations V642I/F/G were discovered in APP695, which has been suggested by multiple studies to be a cell surface signaling receptor. We previously reported that normal APP695 encodes a potential GO-linked receptor with ligand-regulated function and that expression of the three FAD mutants (FAD-APPs), not normal APP, induces cellular outputs by GO-dependent mechanisms. This suggests that FAD-APPs are constitutively active GO-linked receptors. Here, we provide direct evidence for this notion. Reconstitution of either recombinant FAD-APP with GO vesicles induced activation of GO, which was inhibitable by pertussis toxin, sensitive to Mg2+ and proportional in quantity to the reconstituted amounts of FAD-APP. Consistent with the dominant inheritance of this type of FAD, this function was dominant over normal APP, because little activation was observed in APP695-GO vesicles. Experiments with antibody competition and sequence deletion indicated that His657-Lys676 of FAD-APP, which has been specified as the ligand-dependent GO-coupling domain of normal APP, was responsible for this constitutive activation, confirming that the three FAD-APPs are mutationally activated APP695. This study identifies the intrinsic signaling function of APP to be a novel target of hereditary Alzheimer's disease mutations, providing an in vitro system for the screening of potential FAD inhibitors.

Refractory thrombocytopenia with chromosome 11q23 abnormality

Although cytopenia is a common manifestation of myelodysplastic syndrome (MDS), isolated thrombocytopenia is rare. The term "refractory thrombocytopenia" (RTC) has been proposed as a counterpart of refractory anemia. We describe here a case of RTC associated with chromosome abnormality on 11q23. A 59-year-old man was admitted because of severe thrombocytopenia. A bone marrow examination revealed an increased number of micromegakaryocytes and the absence of normal-sized megakaryocytes without obvious dysplasia in either the myeloid or the erythroid lineage. A remarkable increase of GPIIb/IIIa (CD41a)-positive precursor cells in the bone marrow was observed. Cytogenetic examination detected the chromosome abnormality, an addition on chromosome 11q23. Translocation of the HRX gene was not detectable by Southern blot analysis. The diagnostic problems of isolated thrombocytopenia and possible participation of gene(s) on chromosome 11q23 in megakaryocytopoiesis as well as early hematopoiesis are discussed.

Enhancement and repression of cyanide-insensitive respiration in Aspergillus niger

The biosynthesis of the alternative oxidase protein consisting of cyanide-insensitive and salicylhydroxamic acid-sensitive respiration in Aspergillus niger was investigated. Cyanide-insensitive respiration was enhanced by addition of antimycin A to the incubation mixture, but repressed by the addition of cycloheximide, emetine, puromycin (cytosolic translation inhibitors), carbonylcyanide-m-chlorophenylhydrazone (uncoupler) and actinomycin D (transcription inhibitor). These results show that the alternative oxidase protein of A. niger was synthesized de novo in cytosol and transported in mitochondria.

Immunological studies on venereal spirochetosis of rabbits (rabbit syphilis)

White rabbits in a family, which were clinically diagnosed as moderately or severely diseased with spirochetosis, were bacteriologically and immunologically examined. The specimens from the diseased rabbits, including affected prepuces, scrotum, or skins with an occasional presence of the spirochetes, did not, however, result in growth in six conventional culture media. Serological tests, including quantitative complement fixation test, rapid plasma reagin card test, Treponema pallidum hemagglutination test, and microscopic agglutination test for leptospires using sera from diseased rabbits showed no differences when compared with those of pooled normal rabbit sera. Immunoblot analysis of the polypeptides from three human oral treponemes and three non-oral spirochetes demonstrated that antibodies against several treponemal polypeptides were detected.

Three cases of Pasteurella multocida skin infection from pet cats

We encountered three cases of Pasteurella multocida skin infection from pet cats. P. multocida wound infections are characterized by acute onset of erythema, pain, and swelling. This infection has rarely been reported in dermatology journals from Japan.

Optical profilometry of poly(methylmethacrylate) surfaces after reshaping with a scanning photorefractive keratectomy (SPRK) system

A prototype frequency-quintupled Nd:YAG laser was used with a scanning system to create, on poly(methylmethacrylate) (PMMA) blocks, ablations corresponding to a correction of 6 diopters of myopia by photorefractive keratectomy. The topography of the ablated samples was measured with an optical profilometer to evaluate the smoothness and accuracy of the ablations. The ablation depth was larger than expected. With a 50% to 70% spot overlap, large valleylike variations with a maximum peak-to-peak amplitude of 20 µm were observed. With an 80% spot overlap, the rms surface roughness was 1.3 µm, and the central flattening was 7 diopters. This study shows that optical profilometry can be used to determine precisely the ablation per pulse and the smoothness and accuracy of surface ablations. Knowing the exact ablation per pulse is necessary to produce a smooth and accurate corneal surface by scanning photorefractive keratectomy.

Antiproliferative effect of a novel cholecystokinin-B/gastrin receptor antagonist, YM022

Cholecystokinin (CCK)-B and gastrin receptors are expressed on a variety of human tumor cells. Recently, we have demonstrated that the human brain CCK-B receptors are identical to the gastrin receptors derived from the stomach mucosa, and that the brain-gut peptides, CCK-8 and gastrin I are mitogenic for mouse NIH 3T3 fibroblasts expressing human CCK-B/gastrin receptors (N-hCCKBR). In this report, we evaluated the antiproliferative potency of CCK-B/gastrin receptor antagonists by using N-hCCKBR cells. Among several antagonists, a benzodiazepine derivative, YM022 had the most potent activities in competing with [125I]CCK-8 or [125I]gastrin I binding, inhibition of CCK-8- or gastrin I-induced phosphoinositide hydrolysis and increasing cytoplasmic free calcium. Interestingly, a potent antagonist for rat CCK-B/gastrin receptors did not have such activities in N-hCCKBR cells. YM022 inhibited the CCK-8- or gastrin I-induced [methyl-3H]thymidine incorporation of N-hCCKBR cells in a dose-dependent manner. In the absence of exogenous peptide ligands, YM022 also inhibited the proliferation of several human cancer cell lines expressing the genes for both gastrin and its receptor. These results suggest that YM022 could intervene in the autocrine stimulation of human tumor cell lines through CCK-B/gastrin receptors. N-hCCKBR cells are an excellent tool to screen for novel human CCK-B/gastrin receptor antagonists possessing antiproliferative activity for human cancer cells.