Noble gases and nitrogen in samples of asteroid Ryugu record its volatile sources and recent surface evolution

The near-Earth carbonaceous asteroid (162173) Ryugu is expected to contain volatile chemical species that could provide information on the origin of Earth's volatiles. Samples of Ryugu were retrieved by the Hayabusa2 spacecraft. We measured noble gas and nitrogen isotopes in Ryugu samples and found that they are dominated by presolar and primordial components, incorporated during Solar System formation. Noble gas concentrations are higher than those in Ivuna-type carbonaceous (CI) chondrite meteorites. Several host phases of isotopically distinct nitrogen have different abundances among the samples. Our measurements support a close relationship between Ryugu and CI chondrites. Noble gases produced by galactic cosmic rays, indicating a ~5 million year exposure, and from implanted solar wind record the recent irradiation history of Ryugu after it migrated to its current orbit.

Formation and evolution of carbonaceous asteroid Ryugu: Direct evidence from returned samples

Samples of the carbonaceous asteroid Ryugu were brought to Earth by the Hayabusa2 spacecraft. We analyzed 17 Ryugu samples measuring 1 to 8 millimeters. Carbon dioxide-bearing water inclusions are present within a pyrrhotite crystal, indicating that Ryugu's parent asteroid formed in the outer Solar System. The samples contain low abundances of materials that formed at high temperatures, such as chondrules and calcium- and aluminum-rich inclusions. The samples are rich in phyllosilicates and carbonates, which formed through aqueous alteration reactions at low temperature, high pH, and water/rock ratios of <1 (by mass). Less altered fragments contain olivine, pyroxene, amorphous silicates, calcite, and phosphide. Numerical simulations, based on the mineralogical and physical properties of the samples, indicate that Ryugu's parent body formed ~2 million years after the beginning of Solar System formation.

Samples returned from the asteroid Ryugu are similar to Ivuna-type carbonaceous meteorites

Carbonaceous meteorites are thought to be fragments of C-type (carbonaceous) asteroids. Samples of the C-type asteroid (162173) Ryugu were retrieved by the Hayabusa2 spacecraft. We measured the mineralogy and bulk chemical and isotopic compositions of Ryugu samples. The samples are mainly composed of materials similar to those of carbonaceous chondrite meteorites, particularly the CI (Ivuna-type) group. The samples consist predominantly of minerals formed in aqueous fluid on a parent planetesimal. The primary minerals were altered by fluids at a temperature of 37° ± 10°C, about [Formula: see text] million (statistical) or [Formula: see text] million (systematic) years after the formation of the first solids in the Solar System. After aqueous alteration, the Ryugu samples were likely never heated above ~100°C. The samples have a chemical composition that more closely resembles that of the Sun's photosphere than other natural samples do.

Macromolecular organic matter in samples of the asteroid (162173) Ryugu

Samples of the carbonaceous asteroid (162173) Ryugu were collected and brought to Earth by the Hayabusa2 spacecraft. We investigated the macromolecular organic matter in Ryugu samples and found that it contains aromatic and aliphatic carbon, ketone, and carboxyl functional groups. The spectroscopic features of the organic matter are consistent with those in chemically primitive carbonaceous chondrite meteorites that experienced parent-body aqueous alteration (reactions with liquid water). The morphology of the organic carbon includes nanoglobules and diffuse carbon associated with phyllosilicate and carbonate minerals. Deuterium and/or nitrogen-15 enrichments indicate that the organic matter formed in a cold molecular cloud or the presolar nebula. The diversity of the organic matter indicates variable levels of aqueous alteration on Ryugu's parent body.

Soluble organic molecules in samples of the carbonaceous asteroid (162173) Ryugu

The Hayabusa2 spacecraft collected samples from the surface of the carbonaceous near-Earth asteroid (162173) Ryugu and brought them to Earth. The samples were expected to contain organic molecules, which record processes that occurred in the early Solar System. We analyzed organic molecules extracted from the Ryugu surface samples. We identified a variety of molecules containing the atoms CHNOS, formed by methylation, hydration, hydroxylation, and sulfurization reactions. Amino acids, aliphatic amines, carboxylic acids, polycyclic aromatic hydrocarbons, and nitrogen-heterocyclic compounds were detected, which had properties consistent with an abiotic origin. These compounds likely arose from an aqueous reaction on Ryugu's parent body and are similar to the organics in Ivuna-type meteorites. These molecules can survive on the surfaces of asteroids and be transported throughout the Solar System.

A dehydrated space-weathered skin cloaking the hydrated interior of Ryugu

Without a protective atmosphere, space-exposed surfaces of airless Solar System bodies gradually experience an alteration in composition, structure and optical properties through a collective process called space weathering. The return of samples from near-Earth asteroid (162173) Ryugu by Hayabusa2 provides the first opportunity for laboratory study of space-weathering signatures on the most abundant type of inner solar system body: a C-type asteroid, composed of materials largely unchanged since the formation of the Solar System. Weathered Ryugu grains show areas of surface amorphization and partial melting of phyllosilicates, in which reduction from Fe³⁺ to Fe²⁺ and dehydration developed. Space weathering probably contributed to dehydration by dehydroxylation of Ryugu surface phyllosilicates that had already lost interlayer water molecules and to weakening of the 2.7 µm hydroxyl (-OH) band in reflectance spectra. For C-type asteroids in general, this indicates that a weak 2.7 µm band can signify space-weathering-induced surface dehydration, rather than bulk volatile loss.

First asteroid gas sample delivered by the Hayabusa2 mission: A treasure box from Ryugu

The Hayabusa2 spacecraft returned to Earth from the asteroid 162173 Ryugu on 6 December 2020. One day after the recovery, the gas species retained in the sample container were extracted and measured on-site and stored in gas collection bottles. The container gas consists of helium and neon with an extraterrestrial ³He/⁴He and ²⁰Ne/²²Ne ratios, along with some contaminant terrestrial atmospheric gases. A mixture of solar and Earth's atmospheric gas is the best explanation for the container gas composition. Fragmentation of Ryugu grains within the sample container is discussed on the basis of the estimated amount of indigenous He and the size distribution of the recovered Ryugu grains. This is the first successful return of gas species from a near-Earth asteroid.

Pebbles and sand on asteroid (162173) Ryugu: In situ observation and particles returned to Earth

The Hayabusa2 spacecraft investigated the C-type (carbonaceous) asteroid (162173) Ryugu. The mission performed two landing operations to collect samples of surface and subsurface material, the latter exposed by an artificial impact. We present images of the second touchdown site, finding that ejecta from the impact crater was present at the sample location. Surface pebbles at both landing sites show morphological variations ranging from rugged to smooth, similar to Ryugu's boulders, and shapes from quasi-spherical to flattened. The samples were returned to Earth on 6 December 2020. We describe the morphology of >5 grams of returned pebbles and sand. Their diverse color, shape, and structure are consistent with the observed materials of Ryugu; we conclude that they are a representative sample of the asteroid.

Nomograms predicting survival and recurrence in colonic cancer in the era of complete mesocolic excision

Background

More extensive lymphadenectomy may improve survival after resection of colonic cancer. Nomograms were created predicting overall survival and recurrence for patients who undergo D2-D3 lymph node dissection, and their validity determined.

Methods

This was a multicentre study of patients with colonic cancer who underwent resection with D2-D3 lymph node dissection in Japan. Inclusion criteria included R0 resection. A training cohort of patients operated on from 2007 to 2008 was analysed to construct prognostic models predicting survival and recurrence. Discrimination and calibration were performed using an external validation cohort from the Japanese colorectal cancer registry (procedures in 2005-2006).

Results

The training cohort consisted of 2746 patients. Predictors of survival were: age (hazard ratio (HR) 1·04), female sex (HR 0·71), depth of tumour invasion (HR 1·15, 1·22, 2·96 and 3·14 for T2, T3, T4a and T4b respectively versus T1), lymphatic invasion (HR 1·11, 1·15 and 2·95 for ly1, ly2 and ly3 versus ly0), preoperative carcinoembryonic antigen (CEA) level (HR 1·21, 1·59 and 1·99 for 5·1-10·0, 10·1-20·0 and 20·1 and over versus 0-5·0 ng/ml), number of metastatic lymph nodes (HR 1·07), number of lymph nodes examined (HR 0·98) and extent of lymphadenectomy (HR 0·23, 0·13 and 0·11 for D1, D2 and D3 versus D0). Predictors of recurrence were: female sex (HR 0·82), macroscopic type (HR 3·82, 4·56, 6·66, 7·74 and 3·22 for types I, II, III, IV and V versus type 0), depth of invasion (HR 1·25, 2·66, 5·32 and 6·43 for T2, T3, T4a and T4b versus T1), venous invasion (HR 1·43, 3·05 and 4·79 for v1, v2 and v3 versus v0), preoperative CEA level (HR 1·39, 1·43, 1·56 and 1·85 for 5·1-10·0, 10·1-20·0, 20·1-40·0 and 40·1 or more versus 0-5 ng/ml), number of metastatic lymph nodes (HR 1·07) and number of lymph nodes examined (HR 0·98). The validation cohort comprised 4446 patients. The internal and external validated Harrell's C-index values for the nomogram predicting survival were 0·75 and 0·74 respectively. Corresponding values for recurrence were 0·78 and 0·75.

Conclusion

These nomograms could predict survival and recurrence after curative resection of colonic cancer.

Identification of circadian clock modulators from existing drugs

Chronic circadian disruption due to shift work or frequent travel across time zones leads to jet‐lag and an increased risk of diabetes, cardiovascular disease, and cancer. The development of new pharmaceuticals to treat circadian disorders, however, is costly and hugely time‐consuming. We therefore performed a high‐throughput chemical screen of existing drugs for circadian clock modulators in human U2OS cells, with the aim of repurposing known bioactive compounds. Approximately 5% of the drugs screened altered circadian period, including the period‐shortening compound dehydroepiandrosterone (DHEA; also known as prasterone). DHEA is one of the most abundant circulating steroid hormones in humans and is available as a dietary supplement in the USA. Dietary administration of DHEA to mice shortened free‐running circadian period and accelerated re‐entrainment to advanced light–dark (LD) cycles, thereby reducing jet‐lag. Our drug screen also revealed the involvement of tyrosine kinases, ABL1 and ABL2, and the BCR serine/threonine kinase in regulating circadian period. Thus, drug repurposing is a useful approach to identify new circadian clock modulators and potential therapies for circadian disorders.

Hayabusa2 arrives at the carbonaceous asteroid 162173 Ryugu-A spinning top-shaped rubble pile

The Hayabusa2 spacecraft arrived at the near-Earth carbonaceous asteroid 162173 Ryugu in 2018. We present Hayabusa2 observations of Ryugu's shape, mass, and geomorphology. Ryugu has an oblate "spinning top" shape, with a prominent circular equatorial ridge. Its bulk density, 1.19 ± 0.02 grams per cubic centimeter, indicates a high-porosity (>50%) interior. Large surface boulders suggest a rubble-pile structure. Surface slope analysis shows Ryugu's shape may have been produced from having once spun at twice the current rate. Coupled with the observed global material homogeneity, this suggests that Ryugu was reshaped by centrifugally induced deformation during a period of rapid rotation. From these remote-sensing investigations, we identified a suitable sample collection site on the equatorial ridge.

The geomorphology, color, and thermal properties of Ryugu: Implications for parent-body processes

The near-Earth carbonaceous asteroid 162173 Ryugu is thought to have been produced from a parent body that contained water ice and organic molecules. The Hayabusa2 spacecraft has obtained global multicolor images of Ryugu. Geomorphological features present include a circum-equatorial ridge, east-west dichotomy, high boulder abundances across the entire surface, and impact craters. Age estimates from the craters indicate a resurfacing age of [Formula: see text] years for the top 1-meter layer. Ryugu is among the darkest known bodies in the Solar System. The high abundance and spectral properties of boulders are consistent with moderately dehydrated materials, analogous to thermally metamorphosed meteorites found on Earth. The general uniformity in color across Ryugu's surface supports partial dehydration due to internal heating of the asteroid's parent body.

Modeling and simulation of bone mineral density in Japanese osteoporosis patients treated with zoledronic acid using tartrate-resistant acid phosphatase 5b, a bone resorption marker

Annual intravenous administration of zoledronic acid is used in the treatment of osteoporosis. A mathematical model was developed to predict bone mineral density up to 2 years after two annual doses of zoledronic acid from the early values of a bone resorption marker in osteoporosis patients.

INTRODUCTION

The measurement of bone mineral density (BMD) has been used as a surrogate marker instead of the observation of incident fractures to detect the efficacy of treatment. However, this method requires a long time to obtain significant changes. On the other hand, bone resorption markers respond to bone resorption inhibitors within a few weeks. Therefore, the aim of this study was to develop a mathematical model predicting long-term BMD after two annual doses of zoledronic acid (ZOL) using the early response of a bone resorption marker in osteoporosis patients.

METHODS

The model was constructed using 3410 tartrate-resistant acid phosphatase 5b (TRACP-5b) serum concentrations and 1146 lumbar spine (L2-L4) BMD values from 306 patients with primary osteoporosis. A mathematical model was developed to describe the time-dependent profiles of TRACP-5b and BMD.

RESULTS

The percentage changes from baseline of the BMD (%BMD) at up to 2 years were predicted from patients' baseline BMD and baseline and 12-week TRACP-5b values by the model obtained. The simulated 90% prediction interval almost covered the observed %BMD distribution at each time point, and the predictions were comparable to the observed %BMD.

CONCLUSIONS

This is the first model to predict BMD for up to 2 years following two annual doses of ZOL using patients' background characteristics and the early response of TRACP-5b. This model allows us to inform patients at the initial stage of ZOL treatment of their predicted response to treatment.

S-1 as adjuvant chemotherapy for stage III colon cancer: a randomized phase III study (ACTS-CC trial)

BACKGROUND

S-1 is an oral fluoropyrimidine whose antitumor effects have been demonstrated in treating various gastrointestinal cancers, including metastatic colon cancer, when administered as monotherapy or in combination chemotherapy. We conducted a randomized phase III study investigating the efficacy of S-1 as adjuvant chemotherapy for colon cancer by evaluating its noninferiority to tegafur-uracil plus leucovorin (UFT/LV).

PATIENTS AND METHODS

Patients aged 20-80 years with curatively resected stage III colon cancer were randomly assigned to receive S-1 (80-120 mg/day on days 1-28 every 42 days; four courses) or UFT/LV (UFT: 300-600 mg/day and LV: 75 mg/day on days 1-28 every 35 days; five courses). The primary end point was disease-free survival (DFS) at 3 years.

RESULTS

A total of 1518 patients (758 and 760 in the S-1 and UFT/LV group, respectively) were included in the full analysis set. The 3-year DFS rate was 75.5% and 72.5% in the S-1 and UFT/LV group, respectively. The stratified hazard ratio for DFS in the S-1 group compared with the UFT/LV group was 0.85 (95% confidence interval: 0.70-1.03), demonstrating the noninferiority of S-1 (noninferiority stratified log-rank test, P < 0.001). In the subgroup analysis, no significant interactions were identified between the major baseline characteristics and the treatment groups.

CONCLUSION

Adjuvant chemotherapy using S-1 for stage III colon cancer was confirmed to be noninferior in DFS compared with UFT/LV. S-1 could be a new treatment option as adjuvant chemotherapy for colon cancer.

CLINICALTRIALSGOV

NCT00660894.

Evaluation of the quality of life of lupus erythematosus patients with cutaneous lesions in Japan

The quality of life (QOL) of lupus erythematosus (LE) patients with skin manifestations is impaired, but little is known about Japanese patients. We assessed whether the skin symptoms in LE are associated with the QOL using the Japanese versions of the Skindex-29 and Cutaneous Lupus Erythematosus Disease Area and Severity Index (CLASI). In all, 54 LE patients with cutaneous lesions completed the Japanese version of the Skindex-29, and physicians assessed the severity of their eruptions using the CLASI before and after treatment. The QOL of the LE patients was better after the therapeutic intervention using the Skindex-29 questionnaire. We tested several factors for an independent association with the QOL. A significant risk factor for a poor QOL was a female gender in “Functioning” before treatment. In addition, a poor QOL tended to be correlated with a female gender in “Emotions” and older current age in “Symptoms” before treatment, and with a longer duration of SLE in “Functioning” after treatment. In the CLASI analysis, skin manifestation activity in the acute phase correlated with a poor emotional and functional QOL rather than a symptomatic QOL. To the best of our knowledge, this is the first report evaluating the QOL of Japanese LE patients, despite the small cohort.

Fast visible imaging and edge turbulence analysis in QUEST

A fast visible imaging system is installed on the spherical tokamak QUEST to study edge turbulence. The camera uses a complementary metal-oxide semiconductor detector with a maximum resolution of 1024 × 1024 at 7000 frames∕s (fps) and can achieve 775 kfps at a resolution of 128 × 24. In this paper, we present the salient features of the system and its application to study edge turbulence in 8.2 GHz ECRH driven slab plasma, without plasma current. Vertical magnetic field (B(z)) topology is varied with three sets of poloidal field (PF) coils and the variation in the edge turbulence is investigated as a function of the B(z) strength and curvature. Fluctuation amplitude was highest for the shallow PF well. Cross-correlation coefficient shows distinct coherent mode along z direction at the steep density gradient region and it grows with the PF mirror ratio.

A Rho kinase (ROCK) inhibitor, fasudil, prevents matrix metalloproteinase-9-related hemorrhagic transformation in mice treated with tissue plasminogen activator

Thrombolysis with tissue plasminogen activator (tPA) is the only FDA-approved therapy for acute ischemic stroke. However, hemorrhagic transformation, neurotoxicity, and a short treatment time window comprise major limitations for thrombolytic therapy. The purpose of the present study was to investigate whether fasudil, a Rho kinase (ROCK) inhibitor, would prevent tPA-associated hemorrhagic transformation and extend the reperfusion window in an experimental stroke model in mice. Mice subjected to 6-h middle cerebral artery occlusion were treated with delayed tPA alone, with combined tPA plus fasudil, or with a vehicle. We used histological and neurobehavioral measures to assess the effects of the treatment at 18 h and 7 days after the reperfusion. To investigate the mechanism of fasudil's beneficial effects further, we also performed an in vitro study with tPA and fasudil in human brain microvascular endothelial cells. Combination therapy with tPA plus fasudil prevented the development of hemorrhagic transformation, but did not reduce the infarct volumes. These changes significantly reduced mortality and increased locomotor activity at 7 days after the reperfusion. Furthermore, the administration of both drugs prevented injury to the human brain endothelial cells via the reduction of matrix metalloproteinase-9 (MMP-9) activity. These findings indicate that fasudil prevents the hemorrhagic transformation induced by focal cerebral ischemia in mice treated with tPA, at least in part, by inhibiting the increased activity of MMP-9 in endothelial cells.

A broad-spectrum matrix metalloproteinase inhibitor prevents hemorrhagic complications induced by tissue plasminogen activator in mice

Delayed activation of tissue plasminogen activator (tPA) can lead to the disruption of the blood-brain barrier (BBB), resulting in hemorrhagic complications. In the present study, we focused on tight junction proteins (TJPs), occludin, zona occludens (ZO)-1, and claudin-5, which are important structural components of the BBB, and investigated whether inhibition of matrix metalloproteinases (MMPs) provides a protective effect against hemorrhagic complications induced by tPA. We subjected mice to 6-h filamental middle cerebral artery occlusion (MCAO) with vehicle, delayed tPA alone, or combined tPA (10 mg/kg, i.v.) plus GM6001 (100 mg/kg, i.p.), a broad-spectrum MMP inhibitor. We evaluated brain hemoglobin and the expression of MMP-9 and TJPs by immunoblotting. GM6001 significantly reduced tPA-elevated brain hemoglobin, MMP-9, and inhibited the degradation of occludin and ZO-1 induced by tPA, but not claudin-5. Treatment with GM6001 also significantly prevented the decrease in the survival rate and the reduction in locomotor activity caused by tPA at 7 days after ischemia/reperfusion. Furthermore, GM6001 treatment also significantly prevented cell damage, determined by release of lactase dehydrogenase (LDH) activity, and the decrease in transendothelial electrical resistance (TEER) induced by tPA. These findings indicate that GM6001 prevented the hemorrhagic complications and improved the behavioral abnormalities induced by tPA, partly via protection of TJPs. This suggests that GM6001 may be a useful candidate for combination therapy against the hemorrhagic complications induced by tPA.

Forebrain specific heparin-binding epidermal growth factor-like growth factor knockout mice show exacerbated ischemia and reperfusion injury

Heparin-binding epidermal growth factor-like growth factor (HB-EGF) is a hypoxia-inducible neuroprotective protein that also stimulates proliferation of neuronal precursor cells. In this study, we investigated the possible role of HB-EGF in ischemia and reperfusion injury by measuring the changes in its mRNA expression following focal cerebral ischemia. We also examined neural damage after a middle cerebral artery occlusion (MCAO) and reperfusion in ventral forebrain specific HB-EGF knockout (KO) mice. The levels of HB-EGF mRNA in the cerebral cortex of wild-type (WT) mice were significantly increased 3-24 h after MCAO and reperfusion. Cerebral infraction in HB-EGF KO mice was aggravated at 1 day and 6 days after MCAO and reperfusion compared with WT mice. The number of terminal deoxynucleotidyl transferase (TdT)-mediated dNTP nick end labeling (TUNEL) and an oxidative stress marker, 8-hydroxy-2'-deoxyguanosine (8-OHdG) positive cells, were higher in HB-EGF KO mice than in WT mice. On the other hand, fewer bromodeoxyuridine (BrdU) positive cells were found in the subventricular zone in HB-EGF KO mice compared with WT mice. These results indicate that HB-EGF may play a pivotal role in ischemia and reperfusion injury and that endogenously synthesized HB-EGF is necessary for both the neuroprotective effect and for regulation of cell proliferation in the subventricular zone.

Modulation in concentrative nucleoside transporters-mediated intestinal absorption of mizoribine, an immunosuppressive agent, in lipopolysaccharide-treated rats

The characteristics of intestinal absorption of mizoribine and cephalexin, that are mediated by concentrative nucleoside transporters (CNTs) and PEPT1, respectively, was examined in lipopolysaccharide (LPS)-treated rats. LPS treatment is known to modify the expression of some transporters and induce cholestasis. At 24 h after the LPS treatment, averaged concentrations of IL-6 and total bile acids in plasma were 15-fold and 2-fold that in untreated control rats, respectively, and bile flow rate decreased by 40% of control, indicating the induction of inflammatory and cholestatic states. The oral bioavailability, estimated by urinary excretion percentage of unchanged form, of mizoribine in LPS-treated rats was 1.5-fold higher than that in control rats, whereas the bioavailability of cephalexin remained unchanged. When mizoribine and cephalexin were administered into in-situ jejunum loops, there were no differences in the absorption rates between control and LPS-treated rats. These results indicated that the functional expression of CNT1, CNT2, and PEPT1 were not modulated by LPS treatment. When mizoribine (a CNT1/CNT2 substrate) and gemcitabin (a CNT1 substrate) were administered as a solution dissolved in bile into the intestinal loop, their absorption rates decreased significantly. In contrast, the absorption rate of ribavirin (a CNT2 substrate) remained unchanged. In conclusion, LPS treatment exerted no significant effect on the expression of CNT1 and CNT2 in the intestine. Bile was found to suppress the CNT1-mediated intestinal absorption of mizoribine and gemcitabin. The increased oral bioavailability of mizoribine in LPS-treated rats could be ascribed to the less amount of bile or bile acids in the intestine under cholestatic state of rats.

The final report of post-marketing surveillance for cetuximab in colorectal cancer in Japan

590

Background: Cetuximab (ERBITUX) was approved in Jul 2008 in Japan with indication for EGFR-positive and unresectable metastatic or refractory colorectal cancer. Post-marketing surveillance is required by Japanese Health Authority to collect, obtain, verify or validate information on the safety, efficacy and quality of medicines. We conducted this surveillance in all patients treated with cetuximab to access in practical use since clinical data on Japanese patients are limited.

Methods: The target number of patients was 1,800. Following adverse drug reactions were investigated: infusion reaction, skin disorders, interstitial lung diseases, electrolyte abnormalities (including hypomagnesemia), heart toxicities, gastrointestinal disorders, thrombosis/embolism, delayed wound healing, and eye disorders.

Results: Between Sep 2008 until Jan 2010, 2,126 pts registered, 2,006 pts were evaluable for safety (safety population), 1,687 pts for efficacy (efficacy population). Of the 2,006 pts, 1,975 pts (98.5%) were EGFR-positive. Patients characteristics: male/female; 1,234/772 (61.5%/38.5%), median age; 64 (range 18-87), site of primary tumor; colon/rectal/others (multiple selection); 1,235/775/3 (61.6%/38.6%/0.2%), PS0/PS1; 1,370/630 (68.3%/31.4%), combination chemotherapy; cetuximab monotherapy/CPT-11/FOLFIRI: 460/1,255/256 (22.9%/62.56%/12.8%). Of the 2,006 pts, 133 pts (6.6%) and 1,869 pts (93.2%) were treated in second-line and in third-line or later treatment, respectively. The adverse drug reactions incidence was 89.9%. Incidence of skin disorders, gastrointestinal disorders, electrolyte abnormality including hypomagnesaemia, and infusion reaction were 83.7%, 23.1%, 11.5%, and 5.7%, respectively. Efficacy result: Of the 1,687 pts, 658 pts (39.0%) were evaluated to be effective. Of the 658 pts, 614 pts (93.3%) experienced skin adverse reactions.

Conclusions: This post-marketing surveillance confirms the safety and efficacy of cetuximab in the Japanese population treated in clinical practice. The outcome of this surveillance with Japanese 2,006 pts would be useful for clinical use of cetuximab.

[Table: see text]

Clinicopathological features in metastatic colorectal cancer patients with KRAS wild type compared with codon 12 and codon 13 mutant: Results from a multicenter, cross-sectional study by the Japan study group of KRAS mutation in colorectal cancer

407

Background: The KRAS mutation mainly located in the codon 12 and 13 indicates unresponsiveness of patients with metastatic colorectal cancer (CRC) to anti-epidermal growth factor receptor (EGFR) antibodies. Many studies have reported that approximately 30%-40% of CRC patients have KRAS mutations. However, the clinicopathological features of KRAS mutant CRC have not been fully clarified, especially in Asian populations. This study aimed to clarify the clinicopathological features of KRAS mutant CRC in comparison with KRAS wild type in large-scale Japanese population.

Methods: The key eligibility criteria included histologically confirmed colorectal adenocarcinoma with adequate tumor samples. Formalin-fixed paraffin-embedded tumor blocks or thinly sliced tumor sections from 389 centers were sent to commercial laboratories. Almost all KRAS point mutations in the codon 12 and 13 were investigated by direct sequencing (96%). The logistic regression analysis was used to estimate the odds ratios (ORs) and compute 95% confidential intervals (CIs).

Results: Of 5,887 registered tumor samples between Oct. 2009 and Mar. 2010, the KRAS testing were performed for 5,790 samples. As of the cut-off date, Sep. 2010, we have successfully determined the KRAS mutational status of 5,732 samples (99%).The median age was 65 years old, and 61% were male. The primary tumor site was right colon, left colon, and rectum in 30, 38, and 32% patients, respectively. The frequency of KRAS mutation was 37.6% (2,155/5,732), of which the 80% (1,714/2,155) mutations were located in codon 12. On logistic regression analysis, female gender (OR=1.212, 95% CI=1.083-1.356), older age > 50 years (OR=1.312, CI=1.056-1.628) and right colon (versus left: OR=2.177, CI=1.905- 2.489; versus rectum: OR=1.500, CI=1.308-1.720) were independent risk factors of KRAS mutant CRC. Clinicopathological features were similar between codon 12 and 13 mutant CRC.

Conclusions: This study disclosed that KRAS mutant CRC was different from KRAS wild type CRC in terms of clinicopathological features.

No significant financial relationships to disclose.

Synthesis and determination of configuration of natural 25-hydroxyvitamin D(3) 26,23-lactone

The four stereoisomers of 25-hydroxyvitamin D(3) 26,23-lactone were synthesized by a stereoselective lactonization method. Natural 25-hydroxyvitamin D(3) 26,23-lactone was produced from 25-hydroxy-[3alpha-(3)H]vitamin D(3) by in vitro incubation of kidney homogenate prepared from vitamin D-supplemented chickens or was isolated from the serum of rats given 1,25-dihydroxyvitamin D(3) and 25-hydroxy-[3alpha-(3)H]vitamin D(3). The four synthetic isomers and the naturally produced 25-hydroxyvitamin D(3) 26,23-lactone were subjected to high-performance liquid chromatography in a system capable of separating the four isomers. The natural lactone comigrated with synthetic (23S,25R)-25-hydroxyvitamin D(3) 26,23-lactone, establishing it as the natural vitamin D(3) metabolite.

Growth pattern in the muscular layer reflects the biological behaviour of colorectal cancer

OBJECTIVE

To determine the clinical value of evaluating the cancer morphology in muscularis propria (MP) for colorectal cancer (CRC) patients.

METHOD

A total of 994 patients with advanced CRC were reviewed in terms of two distinctive growth patterns in the MP: (i) horizontal spread between the circular and longitudinal muscle layers (H-spread) and (ii) 'streaming' spread between the muscle bundles of the circular muscle layer (S-spread).

RESULTS

The incidence of H-spread (n = 153) and S-spread (n = 150) showed a positive correlation with tumour-node-metastasis (TNM) stage and both exerted a negative impact on postoperative survival. Adverse morphology in the MP (H-spread and/or S-spread) was consistent with a high grade of vascular invasion and budding in the extramural layer, as also with unfavourable fibrotic stromas in the reactive fibrous zone; the 5-year survival rate in patients with such features was 64.2%, which was lower than that in those without (86.5%, P < 0.0001). Multivariate analysis demonstrated that adverse morphology was an independent prognostic determinant, along with T- and N -stage. As the mode of H-spread, perineural invasion in the myenteric plexus was found to be predominant over lymphatic spread on the basis of S100 and CD34 immunostaining, but neural cell adhesion molecule expression, whether on cancer cells or on neural cells, was not significant for this growth pattern.

CONCLUSION

A particular group of CRCs ingeniously utilizes the thin space between muscle fascicles for development in the MP. Although the biological mechanism remains unknown, this distinctive growth pattern could be a useful indicator to identify CRC patients at high risk of recurrence.

Regolith Migration and Sorting on Asteroid Itokawa

High-resolution images of the surface of asteroid Itokawa from the Hayabusa mission reveal it to be covered with unconsolidated millimeter-sized and larger gravels. Locations and morphologic characteristics of this gravel indicate that Itokawa has experienced considerable vibrations, which have triggered global-scale granular processes in its dry, vacuum, microgravity environment. These processes likely include granular convection, landslide-like granular migrations, and particle sorting, resulting in the segregation of the fine gravels into areas of potential lows. Granular processes become major resurfacing processes because of Itokawa's small size, implying that they can occur on other small asteroids should those have regolith.

Developing space weathering on the asteroid 25143 Itokawa

Puzzlingly, the parent bodies of ordinary chondrites (the most abundant type of meteorites) do not seem to be abundant among asteroids. One possible explanation is that surfaces of the parent bodies become optically altered, to become the S-type asteroids which are abundant in the main asteroid belt. The process is called 'space weathering'-it makes the visible and near-infrared reflectance spectrum of a body darker and redder. A recent survey of small, near-Earth asteroids suggests that the surfaces of small S asteroids may have developing stages of space weathering. Here we report that a dark region on a small (550-metre) asteroid-25143 Itokawa-is significantly more space-weathered than a nearby bright region. Spectra of both regions are consistent with those of LL5-6 chondrites after continuum removal. A simple calculation suggests that the dark area has a shorter mean optical path length and about 0.04 per cent by volume more nanophase metallic iron particles than the bright area. This clearly shows that space-weathered materials accumulate on small asteroids, which are likely to be the parent bodies of LL chondrites. We conclude that, because LL meteorites are the least abundant of ordinary (H, L, and LL) chondrites, there must be many asteroids with ordinary-chondrite compositions in near-Earth orbits.

Detailed images of asteroid 25143 Itokawa from Hayabusa

Rendezvous of the Japanese spacecraft Hayabusa with the near-Earth asteroid 25143 Itokawa took place during the interval September through November 2005. The onboard camera imaged the solid surface of this tiny asteroid (535 meters by 294 meters by 209 meters) with a spatial resolution of 70 centimeters per pixel, revealing diverse surface morphologies. Unlike previously explored asteroids, the surface of Itokawa reveals both rough and smooth terrains. Craters generally show unclear morphologies. Numerous boulders on Itokawa's surface suggest a rubble-pile structure.

Touchdown of the Hayabusa Spacecraft at the Muses Sea on Itokawa

After global observations of asteroid 25143 Itokawa by the Hayabusa spacecraft, we selected the smooth terrain of the Muses Sea for two touchdowns carried out on 19 and 25 November 2005 UTC for the first asteroid sample collection with an impact sampling mechanism. Here, we report initial findings about geological features, surface condition, regolith grain size, compositional variation, and constraints on the physical properties of this site by using both scientific and housekeeping data during the descent sequence of the first touchdown. Close-up images revealed the first touchdown site as a regolith field densely filled with size-sorted, millimeter- to centimeter-sized grains.

cDNA microarray analysis of cancer associated gene expression profiles in malignant peripheral nerve sheath tumours

BACKGROUND

Malignant peripheral nerve sheath tumour (MPNST) is a highly aggressive malignancy that arises within peripheral nerves, and is associated with poor prognosis. Little is known about the underlying biology of MPNST, especially the mechanisms involved in cell proliferation, invasion, or escape from apoptosis.

AIMS

To identify genes differentially expressed in MPNST compared with benign tumours, such as neurofibromas and schwannomas, by means of cDNA microarray analysis.

METHODS

Six MPNST cases and five benign cases (three schwannomas and two neurofibromas) were analysed.

RESULTS

Six genes (keratin 18, survivin, tenascin C, adenosine deaminase, collagen type VIa3, and collagen type VIIa1) were significantly upregulated in MPNST, whereas one gene, insulin-like growth factor binding protein 6, was downregulated in MPNST. Survivin and tenascin C expression was validated by reverse transcription polymerase chain reaction. Immunohistochemistry confirmed upregulation of survivin in MPNST at the protein level in six of eight cases compared with benign tumours. Tenascin C was also expressed at the invasive front and tumorous stroma in all MPNST cases. MPNST cells expressed tenascin C in four of nine cases.

CONCLUSIONS

Survivin and tenascin C may be associated with the malignant potential of MPNST and could be considered as potential therapeutic targets.