Internal Delensing of Cosmic Microwave Background Polarization B-Modes with the POLARBEAR Experiment.

Using only cosmic microwave background polarization data from the polarbear experiment, we measure B-mode polarization delensing on subdegree scales at more than 5σ significance. We achieve a 14% B-mode power variance reduction, the highest to date for internal delensing, and improve this result to 22% by applying for the first time an iterative maximum a posteriori delensing method. Our analysis demonstrates the capability of internal delensing as a means of improving constraints on inflationary models, paving the way for the optimal analysis of next-generation primordial B-mode experiments.

Total 25-hydroxyvitamin D levels predict fracture risk: results from the 15-year follow-up of the Japanese Population-based Osteoporosis (JPOS) Cohort Study.

We found that community-dwelling women with 25-hydroxyvitamin D levels <20 ng/mL compared to levels ≥20 ng/mL indicated increased risks for clinical, non-vertebral, and fragility fractures during 5 years. Furthermore, the increased risks of non-vertebral fractures remained significant in 10 and 15 years after adjusting for age and bone mineral density. INTRODUCTION: We examined whether total 25-hydroxyvitamin D (25[OH]D) levels are associated with fracture risk over 15 years in a Japanese female cohort. METHODS: Of 1437 community-dwelling women aged ≥50 years in the baseline survey, 1236 provided information regarding fractures during a 15-year follow-up period. The analysis included 1211 women without early menopause or diseases affecting bone metabolism. RESULTS: Over 15 years, 269 clinical (224 non-vertebral, 149 fragility) fracture events were confirmed. Incidence rates categorized by 25(OH)D levels (<10, 10-20, 20-30, and ≥30 ng/mL) indicated a significant divergence for any clinical fractures in 5 years (log rank test p = 0.016) and for non-vertebral fractures in 5, 10, and 15 years (p < 0.001, p = 0.001, p = 0.017, respectively). Hazard ratios (HRs) for 25(OH)D levels <10 and 10-20 ng/mL compared to levels ≥30 ng/mL during 5 years indicated significances for clinical fractures (HR 4.93 with p = 0.009, HR 3.00 with p = 0.034) and for non-vertebral fractures (HR 6.55 with p = 0.005, HR 3.49 with p = 0.036). Those with levels <20 ng/mL compared to those with levels ≥20 ng/mL indicated significant increased risks for clinical fractures (HR 1.72 with p = 0.010), non-vertebral fractures (HR 2.45 with p < 0.001), and fragility fractures (HR 2.00 with p = 0.032) in 5 years. The HR of non-vertebral fractures for levels <20 ng/mL remained significant during 15 years (HR 1.42 with p = 0.012) after adjustment for age and femoral neck bone mineral density. CONCLUSIONS: Low 25(OH)D levels, especially <20 ng/mL, were associated with elevated fracture risks in Japanese women.

Measurement of the cosmic microwave background polarization lensing power spectrum with the POLARBEAR experiment.

Gravitational lensing due to the large-scale distribution of matter in the cosmos distorts the primordial cosmic microwave background (CMB) and thereby induces new, small-scale B-mode polarization. This signal carries detailed information about the distribution of all the gravitating matter between the observer and CMB last scattering surface. We report the first direct evidence for polarization lensing based on purely CMB information, from using the four-point correlations of even- and odd-parity E- and B-mode polarization mapped over ∼30 square degrees of the sky measured by the POLARBEAR experiment. These data were analyzed using a blind analysis framework and checked for spurious systematic contamination using null tests and simulations. Evidence for the signal of polarization lensing and lensing B modes is found at 4.2σ (stat+sys) significance. The amplitude of matter fluctuations is measured with a precision of 27%, and is found to be consistent with the Lambda cold dark matter cosmological model. This measurement demonstrates a new technique, capable of mapping all gravitating matter in the Universe, sensitive to the sum of neutrino masses, and essential for cleaning the lensing B-mode signal in searches for primordial gravitational waves.

Evidence for gravitational lensing of the cosmic microwave background polarization from cross-correlation with the cosmic infrared background.

We reconstruct the gravitational lensing convergence signal from cosmic microwave background (CMB) polarization data taken by the Polarbear experiment and cross-correlate it with cosmic infrared background maps from the Herschel satellite. From the cross spectra, we obtain evidence for gravitational lensing of the CMB polarization at a statistical significance of 4.0σ and indication of the presence of a lensing B-mode signal at a significance of 2.3σ. We demonstrate that our results are not biased by instrumental and astrophysical systematic errors by performing null tests, checks with simulated and real data, and analytical calculations. This measurement of polarization lensing, made via the robust cross-correlation channel, not only reinforces POLARBEAR auto-correlation measurements, but also represents one of the early steps towards establishing CMB polarization lensing as a powerful new probe of cosmology and astrophysics.

Adipose cells induce phospho-Thr-172 AMPK production by epinephrine or CL316243 in mouse 3T3-L1 adipocytes or MAPK activation and G protein-associated PI3K responses induced by CL316243 or aluminum fluoride in rat white adipocytes.

Responses of adipose cells to adrenoceptor regulation, including that of ß-adrenoceptor (AR), and the signalling machinery involved in these responses are not sufficiently understood; information that is helpful for elucidating the adrenoceptor (adrenergic and ß-AR)-responsive machinery is insufficient. We examined phospho-Thr-172 AMPK production in mouse-derived 3T3-L1 adipocytes treated with epinephrine or CL316243 (a ß3-AR agonist) for 15 min. We also examined MAPK activation or G protein-associated PI3K activation or -associated PI3K p85 complex formation in rat epididymal (white) adipocytes treated with CL316243 for 15 min or aluminum fluoride (a G-protein signalling activator) for 20 min. Furthermore, we examined the effect of PTX (a trimeric G-protein inactivator) on p85 complex formation induced by aluminum fluoride treatment. Western blot analysis revealed that epinephrine or CL316243 treatment increased the phospho- Thr-172 AMPK (an active form of AMPK) level in 3T3-L1 adipocytes. Activated kinase analysis with a specific substrate showed that CL316243 or aluminum fluoride treatment activated MAPK in rat adipocytes. Immunoprecipitation experiments with a G-protein ß subunit (Gß) antibody showed that treatment of rat adipocytes with CL316243 activated PI3K and increased the PI3K p85 level in the Gß antibody immunoprecipitates. Such an increase in the p85 level was similarly elicited by aluminum fluoride treatment in a PTX-sensitive manner. Our results provide possible clues for clarifying the signalling machinery involved in adrenoceptor responses, including those of ß3-AR, in mouse-derived adipocytes and rat white adipocytes. Our findings advance the understanding of responses to adrenoceptor regulation in adipose cells and of the cellular signalling machinery present in the cells.

The Simons Observatory: Cryogenic half wave plate rotation mechanism for the small aperture telescopes.

We present the requirements, design, and evaluation of the cryogenic continuously rotating half-wave plate (CHWP) for the Simons Observatory (SO). SO is a cosmic microwave background polarization experiment at Parque Astronómico de Atacama in northern Chile that covers a wide range of angular scales using both small (⌀0.42 m) and large (⌀6 m) aperture telescopes. In particular, the small aperture telescopes (SATs) focus on large angular scales for primordial B-mode polarization. To this end, the SATs employ a CHWP to modulate the polarization of the incident light at 8 Hz, suppressing atmospheric 1/f noise and mitigating systematic uncertainties that would otherwise arise due to the differential response of detectors sensitive to orthogonal polarizations. The CHWP consists of a 505 mm diameter achromatic sapphire HWP and a cryogenic rotation mechanism, both of which are cooled down to ∼50 K to reduce detector thermal loading. Under normal operation, the HWP is suspended by a superconducting magnetic bearing and rotates with a constant 2 Hz frequency, controlled by an electromagnetic synchronous motor. We find that the number of superconductors and the number of magnets that make up the superconducting magnetic bearing are important design parameters, especially for the rotation mechanism's vibration performance. The rotation angle is detected through an angular encoder with a noise level of 0.07 µrad s. During a cooldown process, the rotor is held in place by a grip-and-release mechanism that serves as both an alignment device and a thermal path. In this paper, we provide an overview of the SO SAT CHWP: its requirements, hardware design, and laboratory performance.

Biochemical markers for bone turnover predict risk of vertebral fractures in postmenopausal women over 10 years: the Japanese Population-based Osteoporosis (JPOS) Cohort Study.

UNLABELLED: We evaluated how bone turnover might predict vertebral fracture risk in postmenopausal women over 10 years. After adjusting for age and femoral neck bone mineral density, high bone-specific alkaline phosphatase and total and free deoxypyridinoline at baseline predicted increased vertebral fracture risk in women with ≥ 5 years since menopause. INTRODUCTION: The aim was to evaluate the ability of bone turnover markers (BTMs) in predicting vertebral fractures. METHODS: Participants in the 1996 baseline survey of the JPOS Cohort Study included 522 postmenopausal women, with no diseases or medications affecting bone metabolism. Vertebral fractures were ascertained in three follow-up surveys (1999, 2002, and 2006). Initial fracture events were diagnosed morphometrically. The Poisson regression model was applied to estimate the rate ratio (RR) of the following log-transformed BTM values at baseline: osteocalcin and bone-specific alkaline phosphatase (BAP) in serum and C-terminal cross-linked telopeptide of type I collagen, total deoxypyridinoline (tDPD), and free deoxypyridinoline (fDPD) in urine. RESULTS: Eighty-three fracture events were diagnosed over a median follow-up period of 10.0 years. RR per standard deviation (SD) (95 % confidence interval) for BAP was 4.38 (1.45, 13.21) among 65 subjects with years since menopause (YSM) < 5 years. RRs per SD (95 % confidence interval) for BAP, tDPD, and fDPD were 1.39 (1.12, 1.74), 1.32 (1.05, 1.67), and 1.40 (1.12, 1.76), respectively, after adjusting for age and femoral neck bone mineral density (FN BMD) among 457 subjects with YSM ≥ 5 years. Of the 451 women followed at least once until 2002, RRs per SD for BAP, tDPD, and fDPD adjusted for age and FN BMD over 6 years were not significantly different from those over 10 years. CONCLUSION: BAP was associated with vertebral fracture risk among early postmenopausal women. BTMs can predict vertebral fractures independently of BMD among late postmenopausal women over a 10-year follow-up period.

Characterization of a half-wave plate for cosmic microwave background circular polarization measurement with POLARBEAR.

A half-wave plate (HWP) is often used as a modulator to suppress systematic error in the measurements of cosmic microwave background (CMB) polarization. A HWP can also be used to measure circular polarization (CP) through its optical leakage from CP to linear polarization. The CP of the CMB is predicted from various sources, such as interactions in the Universe and extension of the standard model. Interaction with supernova remnants of population III stars is one of the brightest CP sources. Thus, the observation of the CP of CMB is a new tool for searching for population III stars. In this paper, we demonstrate the improved measurement of the leakage coefficient using the transmission measurement of an actual HWP in the laboratory. We measured the transmittance of linearly polarized light through the HWP used in Polarbear in the frequency range of 120-160 GHz. We evaluate the properties of the HWP by fitting the data with a physical model using the Markov Chain Monte Carlo method. We then estimate the band-averaged CP leakage coefficient using the physical model. We find that the leakage coefficient strongly depends on the spectra of CP sources. We thus calculate the maximum fractional leakage coefficient from CP to linear polarization as 0.133 ± 0.009 in the Rayleigh-Jeans spectrum. The nonzero value shows that Polarbear has a sensitivity to CP. Additionally, because we use the bandpass of detectors installed in the telescope to calculate the band-averaged values, we also consider systematic effects in the experiment.

Comparison of the prognostic value of inflammation-based prognostic scores in patients with hepatocellular carcinoma.

BACKGROUND: Inflammation-based prognostic scores including the Glasgow Prognostic Score (GPS), neutrophil to lymphocyte ratio (NLR), and Prognostic Nutritional Index (PNI) are associated with survival in patients with hepatocellular carcinoma (HCC). The aim of this study was to investigate the prognostic value of these inflammation-based prognostic scores in patients with HCC. METHODS: In total, 150 patients with newly diagnosed HCC were prospectively evaluated. Patients were divided according to the GPS, modified GPS, NLR, platelet to lymphocyte ratio (PLR), Prognostic Index (PI), and PNI. The area under the receiver operating characteristics curve (AUC) was calculated to compare the predictive ability of each of the scoring systems. A univariate and multivariate analysis were performed to identify the clinicopathological variables associated with overall survival. RESULTS: The GPS consistently had a higher AUC value at 6 months (0.768), 12 months (0.787), and 24 months (0.758) in comparison with other inflammation-based prognostic scores. A multivariate analysis showed that the GPS was independently associated with overall survival. CONCLUSION: This study demonstrates that the GPS, an inflammation-based prognostic score, is an independent marker of poor prognosis in patients with HCC and is superior to the other inflammation-based prognostic scores in terms of prognostic ability.

Polymorphisms in the 5'-UTR of PTEN and other gene polymorphisms in normal Japanese individuals.

Polymorphisms are distributed differently in populations, including those of regions, ethnic groups, and diseased patients. In order to investigate variation in nucleotide sequences in normal individuals, we isolated genomic DNA from the blood of healthy Japanese individuals and sequenced the 5'-untranslated region (5'-UTR) of the phosphatase and tensin homolog deleted on chromosome 10 (PTEN) gene and the gene promoter, intron, and exon nucleotides of p53, p14(ARF), murine double minute 2 (MDM2), and the beta2- and beta3-adrenoceptor (-AR). We found polymorphisms in these regions, including a deletion at positions -465 to -463 and a substitution at position -404 in PTEN and a substitution at position -4924 in p14(ARF), in normal individuals. Individuals with or without the PTEN polymorphism harbored a different distribution of polymorphisms, including simultaneous alterations in nucleotides of p53, MDM2, and beta3-AR, and also harbored some polymorphic nucleotides located in the same set of associatively altered nucleotides. Our results show that multiple nucleotides, including the PTEN nucleotides, are altered in normal Japanese individuals and provide useful information for genotyping studies in individuals and populations.

The POLARBEAR Fourier transform spectrometer calibrator and spectroscopic characterization of the POLARBEAR instrument.

We describe the Fourier Transform Spectrometer (FTS) used for in-field testing of the POLARBEAR receiver, an experiment located in the Atacama Desert of Chile which measures the cosmic microwave background (CMB) polarization. The POLARBEAR-FTS (PB-FTS) is a Martin-Puplett interferometer designed to couple to the Huan Tran Telescope (HTT) on which the POLARBEAR receiver is installed. The PB-FTS measured the spectral response of the POLARBEAR receiver with signal-to-noise ratio >20 for ∼69% of the focal plane detectors due to three features: a high throughput of 15.1 sr cm2, optimized optical coupling to the POLARBEAR optics using a custom designed output parabolic mirror, and a continuously modulated output polarizer. The PB-FTS parabolic mirror is designed to mimic the shape of the 2.5 m-diameter HTT primary reflector, which allows for optimum optical coupling to the POLARBEAR receiver, reducing aberrations and systematics. One polarizing grid is placed at the output of the PB-FTS and modulated via continuous rotation. This modulation allows for decomposition of the signal into different harmonics that can be used to probe potentially pernicious sources of systematic error in a polarization-sensitive instrument. The high throughput and continuous output polarizer modulation features are unique compared to other FTS calibrators used in the CMB field. In-field characterization of the POLARBEAR receiver was accomplished using the PB-FTS in April 2014. We discuss the design, construction, and operation of the PB-FTS and present the spectral characterization of the POLARBEAR receiver. We introduce future applications for the PB-FTS in the next-generation CMB experiment, the Simons Array.

Evaluation of postoperative changes in vascularized iliac bone grafts used for mandibular reconstruction.

Vascularized iliac bone grafts are used for mandibular reconstruction, but the factors affecting graft maintenance are unknown. This study explored the postsurgical changes in vascularized iliac bone grafts in patients who had undergone mandibular reconstruction after segmental resection. The study involved 24 patients (16 men and eight women) with oral tumours or osteoradionecrosis. Thirteen patients required bare bone grafting (BBG) and 11 patients required reconstruction with soft tissue coverage (six with a skin paddle and five with direct closure). The bone graft maintenance rate (with regard to the height of the centre of the graft) was calculated immediately after surgery and at 3, 6, 12, 24, and 36months after surgery. The maintenance rate was significantly lower in the BBG group than in the soft tissue coverage group at 3, 6, 12, 24, and 36months, and in those who were fitted with dentures compared to those who were not at 6, 12, 24, and 36months. Local infection also influenced the maintenance rate, but not significantly so. These findings indicate that the reconstruction technique and denture use can affect the bone graft maintenance rate after mandibular reconstruction with vascularized iliac bone grafts.

Microwave oscillator using piezoelectric thin-film resonator aiming for ultraminiaturization of atomic clock.

We developed a microwave oscillator and a micro electromechanical systems-based rubidium cell for the miniaturization of atomic clocks. A thin-film bulk acoustic resonator (FBAR) having a resonant frequency of the fundamental mode in the 3.5 GHz band was employed instead of a crystal resonator. It delivers a clock transition frequency of Rb atoms of 3.417 GHz without the need for a complicated frequency multiplication using a phase-locked loop. This topology considerably reduces the system scale and power consumption. For downsizing the atomic clock system toward the chip level as well as mass production, a microfabricated gas cell containing Rb and N2 gases was also developed. These microcomponents were incorporated into an atomic clock test bench, resulting in a clock operation with a short-term frequency instability of 2.1 × 10-11 at 1 s. To the best of our knowledge, this is the first report of a coherent population trapping clock operation using an FBAR-based microwave oscillator as well as a microfabricated gas cell.

Environmental enrichment brings a beneficial effect on beam walking and enhances the migration of doublecortin-positive cells following striatal lesions in rats.

Rats raised in an enriched environment (enriched rats) have been reported to show less motor dysfunction following brain lesions, but the neuronal correlates of this improvement have not been well clarified. The present study aimed to elucidate the effect of chemical brain lesions and environmental enrichment on motor function and lesion-induced neurogenesis. Three week-old, recently weaned rats were divided into two groups: one group was raised in an enriched environment and the other group was raised in a standard cage for 5 weeks. Striatal damage was induced at an age of 8 weeks by injection of the neuro-toxins 6-hydroxydopamine (6-OHDA) or quinolinic acid (QA) into the striatum, or by injection of 6-OHDA into the substantia nigra (SN), which depleted nigrostriatal dopaminergic innervation. Enriched rats showed better performance on beam walking compared with those raised in standard conditions, but both groups showed similar forelimb use asymmetry in a cylinder test. The number of bromodeoxyuridine-labeled proliferating cells in the subventricular zone was increased by a severe striatal lesion induced by QA injection 1 week after the lesion, but decreased by injection of 6-OHDA into the SN. Following induction of lesions by striatal injection of 6-OHDA or QA, the number of cells positive for doublecortin (DCX) was strongly increased in the striatum; however, there was no change in the number of DCX-positive cells following 6-OHDA injection into the SN. Environmental enrichment enhanced the increase of DCX-positive cells with migrating morphology in the dorsal striatum. In enriched rats, DCX-positive cells traversed the striatal parenchyma far from the corpus callosum and lateral ventricle. DCX-positive cells co-expressed an immature neuronal marker, polysialylated neural cell adhesion molecule, but were negative for a glial marker. These data suggest that environmental enrichment improves motor performance on beam walking and enhances neuronal migration toward a lesion area in the striatum.

Does response rate of chemotherapy with molecular target agents correlate with the conversion rate and survival in patients with unresectable colorectal liver metastases?: A systematic review.

PURPOSE: This study aimed to evaluate whether the response rate of chemotherapy with molecular target agents correlates with the conversion rate, R0 resection rate, and survival in patients with initially unresectable colorectal liver metastases (CRLM). METHODS: We reviewed the literature of prospective, controlled trials of systemic chemotherapy for patients with unresectable liver-only CRLM, including resectable extrahepatic metastases. Pearson's correlation coefficients were calculated. RESULTS: A total of 26 patient groups from 18 studies were reviewed. The response rate was significantly correlated with the conversion rate (r = 0.66) and R0 resection rate (r = 0.43) in overall patients. In subgroup analysis, only the conversion rate in patients with chemotherapy only (r = 0.75) and anti-EGFR therapy (r = 0.78) were significantly strongly correlated with the response rate. A non-significant strong trend toward correlation between response and conversion rates was observed in patients with bevacizumab (r = 0.73, p = 0.10). The regression line in the scatter plot of patients using bevacizumab showed a less steep slope. This indicated that conversion rates were relatively less affected by response rates under anti-VEGF therapy compared with the other patient groups. The response rate in chemotherapy-only patients was significantly correlated with median progression-free survival (r = 0.61) and overall survival (r = 0.66). CONCLUSIONS: Chemotherapy without molecular target agents and with anti-EGFR agents shows similar results of correlation between response and conversion/R0 resection rates. Under anti-VEGF therapy, conversion would be expected, even with a relatively lower response rate.

ABCB1 C3435T polymorphism influences methotrexate sensitivity in rheumatoid arthritis patients.

OBJECTIVE: Methotrexate (MTX) is most widely used for the treatment of rheumatoid arthritis (RA). However, it has certain drawbacks with regard to individual differences in its therapeutic effects as well as the differences in the patients' response to MTX therapy. We investigated whether multi-drug resistance-1 (ABCB1) C3435T, reduced folate carrier-1 (RFC1) G80A, 5-aminoimidazole-4-carboxamide ribonucleotide transformylase (ATIC) C347G and a 6bp-deletion polymorphism in the 3'-untranslated region of the thymidylase synthase (TYMS) gene are predictive of MTX sensitivity and its adverse effects. METHODS: Patients whose last maintenance dosage of MTX was 6 mg/week or those in whom MTX therapy was changed due to poor response to MTX were regarded as non-responders. The data of 124 RA patients who had received MTX treatment were retrospectively analyzed for polymorphisms in the ABCB1, RFC1, ATIC and TYMS genes, MTX sensitivity and MTX toxicity. RESULTS: There were no significant differences in MTX sensitivity among the genotypes of RFC1, ATIC and TYMS genes. ABCB1 3435TT cases included statistically significantly more non-responders than 3435CC cases according to univariate analysis (crude odds ratio (OR) = 8.91, p = 0.001) and multivariate analysis (adjusted OR = 8.78, p = 0.038). There were no significant differences in MTX toxicity among the genotypes of all the genes. CONCLUSION: These results suggested that the genetic diagnosis of ABCB1 C3435T can be applied to determine MTX sensitivity for the treatment of RA patients. However, further pharmacokinetics studies are required in this regard.

Production and characterization of tumor-degenerating factor.

Degenerative changes of human tumor cells or continuous cell lines occur when they are cocultured with human embryonic fibroblasts. The present study confirmed that the degenerative changes of the target cells were due to a factor secreted from the human fibroblast culture, because the culture supernatant of human fibroblast caused the same degenerative changes as those induced by the coculture. This factor was termed "tumor-degenerating factor" (TDF). TDF was produced in the fibroblast culture as early as the 1st day and increased gradually up to the 8th day. TDF induced the degenerative changes in human KB cells, HeLa cells, FL cells, and PLC/PRF/5 cells but not in human WiDr cells or in fibroblasts. Also, it did not induce the degenerative changes in various murine cells, bovine cells, rabbit cells, or monkey cells, suggesting that TDF has species specificity. Furthermore, human leukocyte interferon enhanced the activity of TDF. TDF with the specific activity of 2.9 U/mg protein was purified by several chromatographies. At a final recovery rate of 14.6%, the specific activity was increased to 9,010 U/mg protein. Its molecular weight was estimated about 26,500-30,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. TDF was relatively stable to heat treatment.

Inhibitory effects of alpha-carotene on proliferation of the human neuroblastoma cell line GOTO.

alpha-Carotene inhibited the proliferation of the human neuroblastoma cell line GOTO in a dose- and time-dependent manner. In addition, it was about 10 times more inhibitory than beta-carotene. Northern blot analysis indicated that alpha-carotene caused maximum suppression of the level of the N-myc messenger RNA of GOTO cells. This suppression occurred within 18 hours of alpha-carotene treatment, after which the level of the N-myc messenger RNA gradually recovered to the basal level. Analysis by flow cytometry indicated that when GOTO cells were exposed to alpha-carotene, they were arrested in the G0-G1 phase of their cell cycle. However, as the level of the N-myc messenger RNA was recovering, these cells resumed normal cycling. These results indicate that the reduction in the level of the N-myc messenger RNA caused by alpha-carotene is closely linked with G0-G1 arrest.

Protection by cycloheximide against cytotoxicity induced by vincristine, colchicine, or delta 12-prostaglandin J2 on human osteosarcoma cells.

We examined the protective effects of cycloheximide against cytotoxicity induced by vincristine, colchicine, delta 12-prostaglandin J2, or other antitumor agents on the human osteosarcoma cell line, KSu. Vincristine at a concentration of 0.5 microgram/ml decreased the initial cell number to 34% during 4 days; however, when cycloheximide (0.5 to 10 micrograms/ml) was coexistent, the decrease of the cell number was suppressed and 68% of the initial cells remained viable at the maximum. Furthermore, 0.1 micrograms/ml of cycloheximide also reduced cytotoxicity of colchicine (0.1 to 5 microM) or delta 12-prostaglandin J2 (1 to 5 micrograms/ml) and reduced the cytotoxicity of 0.1 microgram/ml of doxorubicin or 1 micrograms/ml of mitomycin C, suggesting that protection by cycloheximide is shown against cytotoxicity of various types of antitumor agents even on human malignant cells. Next, protein synthesis was reduced to 52% of a control at 3 h by 0.1 micrograms/ml of cycloheximide, suggesting that protein synthesis inhibition precedes the protection. De novo protein synthesis analysis showed that vincristine (0.5 microgram/ml) does not induce any specific protein, whereas delta 12-prostaglandin J2 (3 or 4 micrograms/ml) induced Mr 70,000 and 90,000 proteins, and these were markedly inhibited by cycloheximide (0.1 microgram/ml). In a cell-cycle study, M-phase arrest by vincristine (0.5 microgram/ml) was inhibited in the presence of 0.1 microgram/ml of cycloheximide, suggesting that cell cycle arrest by cycloheximide may be important for protection. From these data, this protection by cycloheximide seems to be more general than expected before.

Genistein arrests cell cycle progression at G2-M.

Genistein, an isoflavone, is a specific inhibitor of tyrosine kinase and topoisomerase II. However, its effect on cell growth is unknown. Therefore, we examined the effects of genistein on cell growth and cell cycle progression and compared its effects with other flavonoids. Genistein inhibited in a dose-dependent manner the growth of HGC-27 cells derived from human gastric cancer. Flow-cytometric analysis showed that genistein almost completely arrested the cell cycle progression at G2-M. This effect was reversible when genistein was removed from the culture medium. In contrast, other flavonoids such as flavone, luteolin, and the structurally similar daidzein arrested the cell cycle at G1. Consistent with the flow-cytometric analysis, microscopic observation showed that genistein did not increase the mitotic index, which supposes that genistein may arrest the cell cycle at G2 or early M. These results suggest that the G2-M arrest by genistein is a unique effect among flavonoids.