A comparative study of the fluoroquinolone antibacterial agents on the action potential duration in guinea pig ventricular myocardia

We examined the effects of ten fluoroquinolone antibacterial agents, levofloxacin, sitafloxacin, trovafloxacin, ciprofloxacin, gemifloxacin, tosufloxacin, gatifloxacin, grepafloxacin, moxifloxacin and sparfloxacin, on action potentials recorded from guinea pig ventricular myocardia. Sparfloxacin prolonged action potential duration (APD) by about 8% at 10 microM and 41% at 100 microM. Gatifloxacin, grepafloxacin and moxifloxacin also prolonged APD at 100 microM by about 13%, 24% and 25%, respectively. In contrast, levofloxacin, sitafloxacin, trovafloxacin, ciprofloxacin, gemifloxacin and tosufloxacin had little or no APD-prolonging effect at concentrations as high as 100 microM. These findings suggest that there are differences in potency to prolong QT interval among the fluoroquinolones.

In utero evaluation and the long-term prognosis of living infants with cystic hygroma

OBJECTIVE

The aim is to evaluate the natural course and the long-term prognosis of cystic hygroma following live birth.

METHODS

Of 39 cases, 12 were excluded because of either artificial termination or intrauterine treatment. 27 cases were retrospectively classified into 2 groups based on the outcome, and the clinical profiles were compared. The long-term prognosis was analyzed for live births.

RESULTS

5 (18.5%) and 22 (81.5%) cases resulted in live birth and fetal demise, respectively. Both the frequency of hydrops fetalis and the maximum size of the cyst were more significantly associated with a poor prognosis (p < 0.01). Of 5 live births, 3 cases with chromosomal or structural abnormalities were handicapped.

CONCLUSIONS

Hydrops fetalis and cyst size are poor prognostic factors, and fetal chromosome and structural malformations should be taken into account when predicting the long-term prognosis.

A new volumetric evaluation of partial splenic embolization for hypersplenism in biliary atresia

BACKGROUND/PURPOSE

Partial splenic embolization (PSE) has become an important therapeutic modality in the management of hypersplenism in biliary atresia (BA). Fifty percent to 80% of spleen is usually devascularized by embolization. The functional outcome, however, has not been correlated with embolized volume of the spleen. The authors propose a new, reliable method of predicting functional outcome using nonembolized volume of the spleen (NEVS) as an index.

METHODS

Between January 1993 and July 2000, 11 children with BA (2 boys and 9 girls, aged 5 to 10 years) underwent 12 PSE procedures. The follow-up period ranged from 6 to 77 months. The NEVS was calculated by enhanced computed tomography (CT) images, and an index was calculated by dividing NEVS with the predicted splenic volume for body weight (standardized NEVS ratio) 2 weeks after PSE.

RESULTS

Splenic volumes before PSE ranged from 312 to 1,201 cm(3) (mean, 875.8 cm(3)). NEVS ranged from 140 to 485 cm(3) (mean, 340 cm(3)). Standardized NEVS ratio ranged from 2.21 to 7.22 (mean, 4.25). The platelet counts with standardized NEVS ratio below 5.0 (group I) and above 5.0 (group II) were 15.1 x 10(4)/mm(3) and 7.2 x 10(4)/mm(3) at 6-month follow-up, respectively.

CONCLUSIONS

(1) Nonembolized volumetric evaluation is useful in predicting the functional outcome of PSE. (2) Reembolization is indicated for the patients with standardized NEVS above 5.0.

Role of endogenous PACAP in catecholamine secretion from the rat adrenal gland

We elucidated the contribution of endogenous pituitary adenylate cyclase-activating polypeptide (PACAP) to neurally evoked catecholamine secretion from the isolated perfused rat adrenal gland. Infusion of PACAP (100 nM) increased adrenal epinephrine and norepinephrine output. The PACAP-induced catecholamine output responses were inhibited by the PACAP type I receptor antagonist PACAP- (6-38) (30-3,000 nM) but were resistant to the PACAP type II receptor antagonist [Lys1,Pro2,5,Ara3,4,Tyr6]-vasoactive intestinal peptide (LPAT-VIP; 30-3,000 nM). Transmural electrical stimulation (ES; 1-10 Hz) or infusion of ACh (6-200 nM) increased adrenal epinephrine and norepinephrine output. PACAP-(6-38) (3,000 nM), but not LPAT-VIP, also inhibited the ES-induced catecholamine output responses. However, PACAP-(6-38) did not affect the ACh-induced catecholamine output responses. PACAP at low concentrations (0.3-3 nM), which had no influence on catecholamine output, enhanced the ACh-induced catecholamine output responses, but not the ES-induced catecholamine output responses. These results suggest that PACAP is released from the nerve endings to facilitate the neurally evoked catecholamine secretion through PACAP type I receptors in the rat adrenal gland.

Intracellular mechanisms of cGMP-mediated regulation of myocardial contraction

The intracellular mechanisms of cGMP, a major intracellular mediator of nitric oxide that regulates the contractility of cardiac muscle, are still to some extent unknown. To investigate these mechanisms, we observed the effects of 8-bromo-cyclic GMP (8br-cGMP) on myofibrillar Ca2+ sensitivity and Ca2+ handling of the sarcoplasmic reticulum (SR) using beta-escin-skinned preparations from Wistar rat hearts. Both low (1 microM) and high doses (100 microM) of 8br-cGMP significantly decreased the myofibrillar Ca2+ sensitivity obtained from pCa-tension relationships to a similar extent (pCa50; from 6.04 to 5.95 by 1 microM 8br-cGMP and 6.00 to 5.89 by 100 microM 8br-cGMP, respectively, n = 9 each). Whereas this Ca2+ desensitization induced by 100 microM 8br-cGMP was blocked by 1 microM KT5823, a specific inhibitor of cGMP-dependent protein kinase (PKG), not induced by 1 microM 8br-cGMP was not effected by KT5823. When the amount of Ca2+ released from the SR was estimated by the peak amplitude of 25 mM caffeine-induced contractions after constant Ca2+-loading by pCa 6, both doses of 8br-cGMP significantly augmented the caffeine-induced peak force to a similar extent (125 +/- 5.8% by 1 microM 8br-cGMP and 116 +/- 5.1% by 100 microM 8br-cGMP, respectively, n = 6 each). The two observed effects of cGMP (a decrease in myofibrillar Ca2+ sensitivity and an increase in Ca2+ uptake by the SR) may participate in regulating myocardial contraction via nitric oxide. Low and high doses of cGMP seem to work mainly via PKG-independent and PKG-dependent pathways, respectively.

Mental health of scientific researchers. I. Characteristics of job stress among scientific researchers working at a research park in Japan

In order to clarify the characteristics of job stress in scientific researchers, a self-administered questionnaire survey for 16,330 workers was carried out at Tsukuba Research Park City, Japan. The data of 7,063 (43%) workers aged 20-59 years old were analyzed, and the characteristics of job stress in 3,290 scientific researchers were compared with those of 1,799 technicians and 1,849 clerks. The researchers perceived higher quantitative and qualitative workload, greater job control (job decision latitude), and greater reward from work, than did the other two job groups. In addition, young male researchers received a large amount of support from their coworkers, while middle-aged male researchers perceived difficulty in personal relationships with their coworkers. From the viewpoints of the demand-control-support model and the effort-reward imbalance model, the researchers, particularly men, were typically occupied in active jobs, and the large amount of effort required for their work seemed to be balanced by greater reward from work. Compared with male researchers, however, female researchers perceived lesser job demand, lesser job control, and lesser reward from work. The working environment of female researchers may be related to the so-called career stress of working women. The mental health status of these scientific researchers should be examined directly in a future study.

mDia-interacting protein acts downstream of Rho-mDia and modifies Src activation and stress fiber formation

The formin homology protein mDia is a Rho GTPase effector protein that participates in stress fiber formation, cytokinesis, and transcriptional activation of the serum response factor. Although the function of another effector of Rho, Rho-associated kinase, is well established, relatively little is known about the functional mechanism and the downstream targets of mDia. Our recent report of a Rho-mDia-Src-tyrosine kinase pathway suggested an important role for mDia in cell adhesion turnover. We identified a new mDia-interacting protein which is expressed ubiquitously. The new protein mainly binds to the proline-rich region of mDia through its Src homology 3 domain and also binds to Grb2 through its proline-rich domain. The protein is localized at the cell periphery and membrane ruffles and co-localizes with mDia. Co-expression of vSrc and the mDia-interacting protein induces significant morphological changes at focal contacts and activation of vSrc. Furthermore, we found that the mDia-interacting protein plays an important role in stress fiber formation induced by active mDia1. Our results suggest that this new protein regulates actin polymerization and cell adhesion turnover in the downstream portion of the Rho-mDia pathway by interacting with Grb2 and Src.

MRNA and enzyme activity of hepatic 11beta-hydroxysteroid dehydrogenase type 1 are elevated in C57BL/KsJ-db/db mice

To evaluate the importance of 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) in insulin resistant diabetic C57BL/KsJ-db/db mice, we measured the activity and mRNA level of 11beta-HSD1 in the liver of db/db mice and their heterozygote litter mates, db/+m mice. The blood glucose, plasma insulin, and corticosterone levels of db/db mice were significantly higher than those of db/+m mice. Despite hyperinsulinemia, the activity level of this enzyme was significantly higher in db/db mice, and the mRNA level of hepatic 11beta-HSD1 was also significantly higher in db/db mice. Since hepatic 11beta-HSD1 in vivo mainly functions as 11-keto-reductase and does not work as 11beta-oxidase, these results suggest that the rate of hepatic conversion of 11-dehydrocorticosterone to corticosterone is increased in db/db mice, resulting in higher glucocorticoid activity in the liver. The increased hepatic corticosterone concentration due to the elevation of 11beta-HSD1 and high plasma corticosterone concentration may antagonize the action of insulin and cause insulin resistance. These findings have a potentially important implication for relationships between increased hepatic 11beta-HSD1 and insulin resistance in db/db mice. The present paper is the first to demonstrate the increased activities and mRNA level of hepatic 11beta-HSD1 in db/db mice.

The characterization of superoxide production of human neonatal neutrophil

To assess the role of neutrophil in neonatal host defense against microbial infection, we characterized the superoxide anion (O(2-)) production of neonatal neutrophil on a biochemical basis. After taking an appropriate informed consent, neutrophils were obtained from cord blood immediately after transvaginal delivery and divided into two groups: the Preterm group, 15 neonates (27-36 weeks' gestation) and the Term group, 15 neonates (37-41 weeks' gestation). Eleven healthy adults served as controls in the Adult group. The value of N-formyl-methionyl-leucyl-phenylalanin (fMLP)-induced O(2-) production activity of neutrophils in the Preterm group using chemiluminescence assay was significantly lower than those values in both the Term and Adult groups (5.77+/-0.53x10(6) vs. 11.1+/-0.94x10(6) and 10.7+/-0.63x10(6) cpm; mean+/-S.E.M., p<0.05). In phorbol 12-myristate 13-acetate (PMA)-stimulation, the values of O(2-) production activity of neutrophils in both the Preterm and Term groups were significantly lower than that in the Adult group (13.0+/-1.66x10(6) and 18.0+/-1.44x10(6) vs. 27.3+/-1.45x10(6) cpm, p<0.05). Scatchard analysis of [(3)H]fMLP binding to neutrophil demonstrated a two-receptor model in each group, and the number of high-affinity receptors per neutrophil in the Preterm group was significantly lower than those in other groups (p<0.05). However, cord blood levels of proinflammatory cytokines, such as interleukin (IL)-6, -8, and tumor necrosis factor-alpha (TNF-alpha) did not differ in either neonatal group. These results indicated that the fMLP-induced O(2-)production activity of neutrophils in the term neonates was enhanced at the level of the receptor and suggested that this enhanced production contribute to the neonatal host defense against microbial infection.

Mutational analysis of BRCA1 and BRCA2 and clinicopathologic analysis of ovarian cancer in 82 ovarian cancer families: two common founder mutations of BRCA1 in Japanese population

We analyzed genetic alterations in BRCA1 and BRCA2 genes among 82 ovarian cancer families in Japan. The clinical characteristics of BRCA-associated ovarian cancer patients were compared with cases carrying no mutations as well as with population controls. Using a direct sequencing method, 45 of the 82 ovarian cancer families were found to carry BRCA1 or BRCA2 germ-line mutations (40 with BRCA1 and 5 with BRCA2). In 24 independent mutations of BRCA1, 5 recurrent mutations were found and 2 of them, the L63X and Q934X mutations, were detected in seven and eight independent families, respectively. In addition, 16 mutations of BRCA1 and 3 mutations of BRCA2 have never been described previously. In consideration of clinicopathological features, there was a significantly higher proportion of tumors with serous adenocarcinoma and of cases of advanced stages in the BRCA1 or BRCA2 cases than in those of the controls. On the other hand, there were no differences of mean age at diagnosis between patients with BRCA1 or BRCA2 mutation and those of the controls. Our results indicate that the features of BRCA-associated ovarian cancer in Japan appear to be similar to those in Western countries, and the L63X and Q934X mutations of BRCA1 appear to be common founder mutations unique to the Japanese population.

Circumvention of acquired resistance to doxorubicin in K562 human leukemia cells by oxatomide

We studied the effect of oxatomide, an antiallergic drug, on the resistance of K562 cells to doxorubicin. Oxatomide synergistically potentiated the cytotoxicity of doxorubicin in doxorubicin-resistant K562 cells (K562/DXR) at a concentration of 1-10 microM, but had hardly any synergistic effect on the parental cell line (K562) at the same concentration. Oxatomide inhibit P-glycoprotein pump-efflux activity and the binding of [3H]-azidopine to the cell-surface protein P-glycoprotein, in a dose-related manner. These results indicate that oxatomide reverses the multidrug-resistance phenotype through direct interaction with P-glycoprotein.

Absence of arabinan in the side chains of the pectic polysaccharides strongly associated with cell walls of Nicotiana plumbaginifolia non-organogenic callus with loosely attached constituent cells

When leaf disks from haploid plants of Nicotiana plumbaginifolia Viv. were transformed with T-DNA and cultured on shoot-inducing medium, nonorganogenic callus. designated nolac (for non-organogenic callus with loosely attached cells), appeared on approximately 7% of leaf disks. In contrast, normal callus was generated on T-DNA-transformed leaf disks from diploid plants and on non-transformed leaf disks from haploid and diploid plants. Transmission electron microscopy revealed that the middle lamellae and the cell walls of one line of mutant callus (nolac-H14) were barely stained by ruthenium red. even after demethylesterification with NaOH, whereas the entire cell wall and the middle lamella were strongly stained in normal callus. In cultures of nolac-H14 callus, the level of sugar components of pectic polysaccharides in the hemicellulose fraction was reduced and that in the culture medium was elevated, as compared with cultures of normal callus. These results indicate that pectic polysaccharides are not retained in the cell walls and middle lamellae of nolac-H14 callus. In nolac-H14, the ratio of arabinose to galactose was low in the pectic polysaccharides purified from all cell wall fractions and from the medium, in particular, in the hemicellulose fractions. The low levels of arabinofuranosyl (T-Araf, 5-Araf, 2,5-Araf, and 3,5-Araf) residues in the pectic polysaccharides of the hemicellulosic fraction of nolac-H,14 indicated that no neutral-sugar side chains, composed mainly of linear arabinan. were present in nolac-H14. Arabinose-rich pectins. which are strongly associated with cellulose-hemicellulose complexes, might play an important role in intercellular attachment in the architecture of the cell wall.

Quantitative analysis of gene expressions of vascular endothelial growth factor-related factors and their receptors in renal cell carcinoma

Vascular endothelial growth factor (VEGF)-related factors are believed to regulate angiogenesis, an essential event in the growth of solid tumors. In this study, we investigated the expression of VEGF-related factor genes (VEGF, VEGF-B, and VEGF-C) and their receptor genes (VEGFR-1 and VEGFR-2) in renal cell carcinoma (RCC). There were significant differences in the expression level of VEGF, VEGFR-1 and VEGFR-2 between RCC and the corresponding normal renal tissue. The expression level of VEGF in the tumor tissue significantly correlated with those of VEGFR-1 and VEGFR-2. Expression levels VEGF-B and VEGF-C genes were not significantly different between RCC and normal renal tissue. A moderate to high protein expression for VEGF, VEGFR-1, and VEGFR-2 was observed in both the tumor cells and the endothelial cells, whereas the protein expression was low for VEGF-B and VEGF-C. The present results suggested that VEGF and its receptors VEGFR-1 and VEGFR-2 cooperates to play a crucial role in the angiogenesis of RCC, while VEGF-B and VEGFR-C may not. Furthermore, since VEGFR-1 and VEGFR-2 proteins were expressed in the tumor cells as well as in the endothelial cells, these receptors may also be responsible for the progression of RCC.

Arch-first reconstruction via median sternotomy. Short retrograde cerebral perfusion

In December 1998, we introduced arch-first reconstruction for total aortic arch replacement via conventional median sternotomy in order to shorten the duration of retrograde cerebral perfusion (RCP). We used a separate straight graft for an elephant trunk, which allowed an easy subsequent distal anastomosis. The average RCP duration in this series was 32.1+/-5.8 min (mean+/-SD, range, 24-40 min, n=12), which was significantly shorter (p<0.05) than that of the conventional procedure (45.6+/-12.4 min, range, 34-65 min, n=8), in which we first perform a distal anastomosis. No significant differences in cardiopulmonary bypass time (268+/-81 min vs 258+/-42 min) nor operation time (518+/-213 min vs 517+/-82 min) between the two groups were observed. There was no hospital death in either group. One patient in the second series (conventional method) suffered temporary neurological disturbance. For acceptable RCP duration, total aortic arch replacement is currently the standard procedure in our institution for Stanford A type aortic dissection.

Enhanced expression of B7-1, B7-2, and intercellular adhesion molecule 1 in sinusoidal endothelial cells by warm ischemia/reperfusion injury in rat liver

To elucidate a role of costimulatory molecule and cell adhesion molecule in hepatic ischemia/reperfusion injury, we examined an alteration in B7-1 (CD80), B7-2 (CD86), and intercellular adhesion molecule 1 (ICAM-1; CD54) expression in the rat liver after warm ischemia/reperfusion injury. To induce hepatic warm ischemia in a rat model, both portal vein and hepatic artery entering the left-lateral and median lobes were occluded by clamping for 30 minutes or 60 minutes, and then reperfused for 24 hours. B7-1, B7-2, and ICAM-1 expressions in the liver were analyzed by immunofluorescence staining and real-time reverse transcription polymerase chain reaction (RT-PCR). Although B7-1 and B7-2 expressions were at very low levels in the liver tissues from normal or sham-operated control rats, both B7-1 and B7-2 expressions were enhanced at protein and messenger RNA (mRNA) levels in the affected, left lobes after warm ischemia/reperfusion. ICAM-1 protein and mRNA were constitutively expressed in the liver of normal and sham-operated control rats, and further up-regulated after warm ischemia/reperfusion. Localization of increased B7-1, B7-2, and ICAM-1 proteins, as well as von Willebrand factor as a marker protein for endothelial cells, was confined by immunofluorescence staining to sinusoidal endothelial cells in hepatic lobules. Data from quantitative real-time RT-PCR analysis revealed that B7-1 and B7-2 mRNA levels were elevated in hepatic lobes after warm ischemia/reperfusion (5.13- and 52.9-fold increase, respectively), whereas ICAM-1 mRNA expression was rather constitutive but further enhanced by warm ischemia/reperfusion (4.24-fold increase). These results suggest that hepatic sinusoidal endothelial cells play a pivotal role as antigen-presenting cells by expressing B7-1 and B7-2 in warm hepatic ischemia/reperfusion injury, and that B7-1 and/or B7-2 might be the primary target to prevent early rejection and inflammatory reactions after hepatic ischemia/reperfusion injury associated with liver transplantation.

Cysteine proteinase gene expression in the endosperm of germinating carrot seeds

A gene for carrot seed cysteine proteinase (CSCP; AB057371, AB057372) was cloned using PCR. The deduced amino acid sequence of CSCP had active sites for eukaryotic cysteine proteinases, putative signal sequences, and an endoplasmic reticulum targeting sequence. RNA gel blot analysis showed that CSCP transcripts appeared from dry seed, reached a maximum 3 days after imbibition (DAI), and disappeared by 5 DAI. In situ hybridization showed that CSCP transcripts accumulated in the endosperm of germinating seeds. This is the first report of the expression pattern of a cysteine proteinase gene in the endosperm of germinating dicotyledonous plants. The promoter of the CSCP gene had an endosperm motif and many other motifs also found in the promoters of endosperm-specific storage protein genes in monocotyledons. It is suggested that dicotyledons, like monocotyledons, have a temporal and spatial regulation system for endosperm-specific gene expression in germinating seeds.

Doppler velocimetry in the adrenal artery in human fetuses

BACKGROUND

Fetal hypoxia and/or acidosis causes redistribution of blood flow to the high-priority organs including the adrenal glands. Although this phenomenon is well described in the human cerebral and placental circulations using Doppler velocimetry, there are few reports about the adrenal glands.

AIM

To clarify the gestational age-related changes in adrenal blood flow in normal fetuses and fetuses at risk of hemodynamic derangement.

MATERIAL AND METHODS

In 153 normal cases, the resistance indices (RIs) calculated from the blood flow velocity waveforms (FVWs) in the middle adrenal artery (MAA) were obtained from 24 weeks to construct nomogram using regression analysis. Twenty-seven complicated cases were divided according to the 5%ile RI values in the MAA, and clinical outcomes were retrospectively compared.

RESULT

The RI values in the MAA increased until 31 weeks and decreased thereafter. The 50%ile regression curve was represented as RI=-0.000914 (weeks)(2)+0.0579 weeks-0.181. Of the 27 complicated cases, 13 had RIs in the MAA below the 5%ile. Cases with low RI had significantly higher RI ratio in regard of UA/MCA; higher occurrence of abnormal FHR patterns on observation; higher incidence of cesarean delivery for nonreassuring fetal well-being status; earlier gestational age at delivery; lower birth weights and longer periods of admission to NICU than the cases with normal RI.

CONCLUSION

We have described the nomogram for the RI in the MAA. In conditions of fetal hypoxia or acidemia, blood flow redistribution to the adrenal glands may occur and the analysis of the adrenal artery FVWs may be useful in detection of fetal altered hemodynamics.

Solitary fibrous tumor of renal pelvis

A 70-year-old Japanese man was referred because of a right renal mass of 2 years in duration. Imaging studies, including magnetic resonance imaging, revealed an ovoid mass, with relatively abundant vascularity, in the right renal pelvis. Right radical nephrectomy was done and a tumor measuring 6.0 x 4.5 x 4.0 cm was found in the renal pelvis. Solitary fibrous tumor (SFT) was highly suspected by histology. Immunohistochemical study using a monoclonal antibody directed against the human hematopoietic progenitor cell antigen (CD34) stain confirmed SFT. This is the first case of SFT of the renal pelvis. Although SFT is extremely rare in urogenital organs, this tumor must be included in the differential diagnosis when we encounter urogenital tumors consisting of mesenchymal elements.

Efficacy of oral UFT plus leucovorin therapy for colon cancer with ovarian and multiple liver metastases: report of two cases

Case 1: a patient was diagnosed as having ascending colon cancer with right ovarian metastasis, and underwent palliative right hemicolectomy plus oophorectomy. The tumor was a well-differentiated adenocarcinoma with right ovarian metastasis, and the disease was classified as stage IV. Oral chemotherapy with UFT plus LV was performed for about 3 years, and the patient is still being followed up with no recurrence at 5 years postoperatively. Case 2: a patient was diagnosed as having incomplete large bowel obstruction caused by ascending colon cancer, and underwent curative right hemicolectomy. The tumor was a moderately differentiated adenocarcinoma, and the disease was classified as stage II. Since multiple liver metastases developed at 3 months postoperatively, oral chemotherapy with UFT plus LV was started. Imaging studies showed the complete elimination of liver metastases after 2 months. Subsequently, liver metastasis recurred about 10 months later. The patient died of unrelated cerebral infarction at 2 years and 6 months postoperatively.

Identification of AF17 as a downstream gene of the beta-catenin/T-cell factor pathway and its involvement in colorectal carcinogenesis

To elucidate the molecular mechanism of colorectal carcinogenesis, we have been attempting to isolate genes involved in the beta-catenin/T-cell factor pathway. In the experiments reported here, analysis by cDNA microarray indicated that AF17, a fusion partner of the MLL gene in acute leukemias with t(11;17)(q23;q21), was transactivated according to accumulation of beta-catenin. Expression of AF17 was significantly enhanced in 8 of the 12 colorectal cancer tissues examined. Introduction of a plasmid designed to express AF17 stimulated growth of NIH3T3 cells, and fluorescence-activated cell sorter analysis indicated that the AF17 regulation of cell-cycle progression was occurring mainly at the G(2)-M transition. Our results suggest that the AF17 gene product is likely to be involved in the beta-catenin-T-cell factor/lymphoid enhancer factor signaling pathway and to function as a growth-promoting, oncogenic protein. These findings should aid development of new strategies for diagnosis, treatment, and prevention of colon cancers and acute leukemias by clarifying the pathogenesis of these conditions.