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.

Copper-Nanocoated Ultra-Small Cells in Grain Boundaries Inside an Extinct Vent Chimney

Chemosynthetic organisms flourish around deep-sea hydrothermal vents where energy-rich fluids are emitted from metal sulfide chimneys. However, microbial life hosted in mineral assemblages in extinct chimneys lacking fluid venting remains largely unknown. The interior of extinct chimneys remains anoxic where the percolation of oxygenated seawater is limited within tightly packed metal sulfide grains. Given the scarcity of photosynthetic organics in deep seawater, anaerobic microbes might inhabit the grain boundaries energetically depending on substrates derived from rock-water interactions. In this study, we reported ultra-small cells directly visualized in grain boundaries of CuFeS₂ inside an extinct metal sulfide chimney from the southern Mariana Trough. Nanoscale solid analyses reveal that ultra-small cells are coated with Cu₂O nanocrystals in grain boundaries enriched with C, N, and P. In situ spectroscopic and spectrometric characterizations demonstrate the distribution of organics with amide groups and a large molecular organic compound in the grain boundaries. We inferred that the ultra-small cells are anaerobes because of the fast dissolution of Cu₂O nanocrystals in oxygenated solution. This Cu₂O property also excludes the possibility of microbial contamination from ambient seawater during sampling. It is shown by 16S rRNA gene sequence analysis that the chimney interior is dominated by Pacearchaeota known to have anaerobic metabolisms and ultra-small cells. Our results support the potential existence of photosynthesis-independent microbial ecosystems in grain boundaries in submarine metal sulfides deposits on the early Earth.

Serpentinimonas gen. nov., Serpentinimonas raichei sp. nov., Serpentinimonas barnesii sp. nov. and Serpentinimonas maccroryi sp. nov., hyperalkaliphilic and facultative autotrophic bacteria isolated from terrestrial serpentinizing springs

Three highly alkaliphilic bacterial strains designated as A1T, H1T and B1T were isolated from two highly alkaline springs at The Cedars, a terrestrial serpentinizing site. Cells from all strains were motile, Gram-negative and rod-shaped. Strains A1T, H1T and B1T were mesophilic (optimum, 30 °C), highly alkaliphilic (optimum, pH 11) and facultatively autotrophic. Major cellular fatty acids were saturated and monounsaturated hexadecenoic and octadecanoic acids. The genome size of strains A1T, H1T and B1T was 2 574 013, 2 475 906 and 2 623 236 bp, and the G+C content was 66.0, 66.2 and 66.1 mol%, respectively. Analysis of the 16S rRNA genes showed the highest similarity to the genera Malikia (95.1-96.4 %), Macromonas (93.0-93.6 %) and Hydrogenophaga (93.0-96.6 %) in the family Comamonadaceae. Phylogenetic analysis based on 16S rRNA gene and phylogenomic analysis based on core gene sequences revealed that the isolated strains diverged from the related species, forming a distinct branch. Average amino acid identity values of strains A1T, H1T and B1T against the genomes of related members in this family were below 67 %, which is below the suggested threshold for genera boundaries. Average nucleotide identity by blast values and digital DNA-DNA hybridization among the three strains were below 92.0 and 46.6 % respectively, which are below the suggested thresholds for species boundaries. Based on phylogenetic, genomic and phenotypic characterization, we propose Serpentinimonas gen. nov., Serpentinimonas raichei sp. nov. (type strain A1T=NBRC 111848T=DSM 103917T), Serpentinimonas barnesii sp. nov. (type strain H1T= NBRC 111849T=DSM 103920T) and Serpentinimonas maccroryi sp. nov. (type strain B1T=NBRC 111850T=DSM 103919T) belonging to the family Comamonadaceae. We have designated Serpentinimonas raichei the type species for the genus because it is the dominant species in The Cedars springs.

Probing the hydrothermal system of the Chicxulub impact crater

The ~180-km-diameter Chicxulub peak-ring crater and ~240-km multiring basin, produced by the impact that terminated the Cretaceous, is the largest remaining intact impact basin on Earth. International Ocean Discovery Program (IODP) and International Continental Scientific Drilling Program (ICDP) Expedition 364 drilled to a depth of 1335 m below the sea floor into the peak ring, providing a unique opportunity to study the thermal and chemical modification of Earth's crust caused by the impact. The recovered core shows the crater hosted a spatially extensive hydrothermal system that chemically and mineralogically modified ~1.4 × 105 km3 of Earth's crust, a volume more than nine times that of the Yellowstone Caldera system. Initially, high temperatures of 300° to 400°C and an independent geomagnetic polarity clock indicate the hydrothermal system was long lived, in excess of 106 years.

Deep microbial proliferation at the basalt interface in 33.5-104 million-year-old oceanic crust

The upper oceanic crust is mainly composed of basaltic lava that constitutes one of the largest habitable zones on Earth. However, the nature of deep microbial life in oceanic crust remains poorly understood, especially where old cold basaltic rock interacts with seawater beneath sediment. Here we show that microbial cells are densely concentrated in Fe-rich smectite on fracture surfaces and veins in 33.5- and 104-million-year-old (Ma) subseafloor basaltic rock. The Fe-rich smectite is locally enriched in organic carbon. Nanoscale solid characterizations reveal the organic carbon to be microbial cells within the Fe-rich smectite, with cell densities locally exceeding 10¹⁰ cells/cm³. Dominance of heterotrophic bacteria indicated by analyses of DNA sequences and lipids supports the importance of organic matter as carbon and energy sources in subseafloor basalt. Given the prominence of basaltic lava on Earth and Mars, microbial life could be habitable where subsurface basaltic rocks interact with liquid water.

Development of a sample holder for synchrotron radiation-based computed tomography and diffraction analysis of extraterrestrial materials

A sample holder for a suite of synchrotron radiation measurements on extraterrestrial materials, which are fragile and irregularly shaped, was developed using carbon nanotubes and polyimide. The holder enables investigation of such samples with multiple analytical instruments, which means that we can reduce the number of sample transfers between holders. The holder developed in our study also enables investigation of such samples without exposure to the terrestrial atmosphere, which contains abundant contaminants, such as water vapor and organic substances. The stability of the samples in the holder during the measurements and disturbance of the analysis result by the holder were evaluated, which showed that sample drift motion and image disturbance due to x-ray attenuation and scattering of the holder materials are insignificant.

Discovery of fossil asteroidal ice in primitive meteorite Acfer 094

Carbonaceous chondrites are meteorites believed to preserve our planet's source materials, but the precise nature of these materials still remains uncertain. To uncover pristine planetary materials, we performed synchrotron radiation-based x-ray computed nanotomography of a primitive carbonaceous chondrite, Acfer 094, and found ultraporous lithology (UPL) widely distributed in a fine-grained matrix. UPLs are porous aggregates of amorphous and crystalline silicates, Fe─Ni sulfides, and organics. The porous texture must have been formed by removal of ice previously filling pore spaces, suggesting that UPLs represent fossils of primordial ice. The ice-bearing UPLs formed through sintering of fluffy icy dust aggregates around the H₂O snow line in the solar nebula and were incorporated into the Acfer 094 parent body, providing new insight into asteroid formation by dust agglomeration.

Extended chondrule formation intervals in distinct physicochemical environments: Evidence from Al-Mg isotope systematics of CR chondrite chondrules with unaltered plagioclase

Al-Mg isotope systematics of twelve FeO-poor (type I) chondrules from CR chondrites Queen Alexandra Range 99177 and Meteorite Hills 00426 were investigated by secondary ion mass spectrometry (SIMS). Five chondrules with Mg#'s of 99.0 to 99.2 and Δ¹⁷O of -4.2‰ to -5.3‰ have resolvable excess ²⁶Mg. Their inferred (²⁶Al/²⁷Al)₀ values range from (3.5 ± 1.3) × 10^‒6 to (6.0 ± 3.9) × 10^‒6. This corresponds to formation times of 2.2 (-0.5/+1.1) Myr to 2.8 (‒0.3/+0.5) Myr after CAIs, using a canonical (²⁶Al/²⁷Al)₀ of 5.23 × 10^-5, and assuming homogeneously distributed ²⁶Al that yielded a uniform initial ²⁶Al/²⁷Al in the Solar System. Seven chondrules lack resolvable excess ²⁶Mg. They have lower Mg#'s (94.2 to 98.7) and generally higher Δ¹⁷O (-0.9‰ to -4.9‰) than chondrules with resolvable excess ²⁶Mg. Their inferred (²⁶Al/²⁷Al)₀ upper limits range from 1.3 × 10^‒6 to 3.2 × 10^‒6, corresponding to formation >2.9 to >3.7 Myr after CAIs. Al-Mg isochrons depend critically on chondrule plagioclase, and several characteristics indicate the chondrule plagioclase is unaltered: (1) SIMS ²⁷Al/²⁴Mg depth profile patterns match those from anorthite standards, and SEM/EDS of chondrule SIMS pits show no foreign inclusions; (2) transmission electron microscopy (TEM) reveals no nanometer-scale micro-inclusions and no alteration due to thermal metamorphism; (3) oxygen isotopes of chondrule plagioclase match those of coexisting olivine and pyroxene, indicating a low extent of thermal metamorphism; and (4) electron microprobe data show chondrule plagioclase is anorthite-rich, with excess structural silica and high MgO, consistent with such plagioclase from other petrologic type 3.00-3.05 chondrites. We conclude that the resolvable (²⁶Al/²⁷Al)₀ variabilities among chondrules studied are robust, corresponding to a formation interval of at least 1.1 Myr. Using relationships between chondrule (²⁶Al/²⁷Al)₀, Mg#, and Δ¹⁷O, we interpret spatial and temporal features of dust, gas, and H₂O ice in the FeO-poor chondrule-forming environment. Mg# ≥ 99, Δ¹⁷O ~-5‰ chondrules with resolvable excess ²⁶Mg initially formed in an environment that was relatively anhydrous, with a dust-to-gas ratio of ~100×. After these chondrules formed, we interpret a later influx of ¹⁶O-poor H₂O ice into the environment, and that dust-to-gas ratios expanded (100× to 300×). This led to the later formation of more oxidized Mg# 94-99 chondrules with higher Δ¹⁷O (-5‰ to -1‰), with low (²⁶Al/²⁷Al)₀, and hence no resolvable excess ²⁶Mg. We refine the mean CR chondrite chondrule formation age via mass balance, by considering that Mg# ≥ 99 chondrules generally have resolved positive (²⁶Al/²⁷Al)₀ and that Mg# < 99 chondrules generally have no resolvable excess ²⁶Mg, implying lower (²⁶Al/²⁷Al)₀. We obtain a mean chondrule formation age of 3.8 ± 0.3 Myr after CAIs, which is consistent with Pb-Pb and Hf-W model ages of CR chondrite chondrule aggregates. Overall, this suggests most CR chondrite chondrules formed immediately before parent body accretion.

Quasielastic neutron scattering of brucite to analyse hydrogen transport on the atomic scale

It is demonstrated that quasielastic neutron scattering is a novel and effective method to analyse atomic scale hydrogen transport processes occurring within a mineral crystal lattice. The method was previously characterized as sensitive for analysing the transport frequency and distance of highly diffusive hydrogen atoms or water molecules in condensed matter. Here are shown the results of its application to analyse the transport of much slower hydrogen atoms which are bonded into a crystal lattice as hydroxyls. Two types of hydrogen transport process were observed in brucite, Mg(OH)₂: a jump within a single two-dimensional layer of the hydrogen lattice and a jump into the next nearest layer of it. These transport processes observed within the prototypical structure of brucite have direct implications for hydrogen transport phenomena occurring within various types of oxides and minerals having layered structures.

Discovery of moganite in a lunar meteorite as a trace of H2O ice in the Moon's regolith

Moganite, a monoclinic SiO₂ phase, has been discovered in a lunar meteorite. Silica micrograins occur as nanocrystalline aggregates of mostly moganite and occasionally coesite and stishovite in the KREEP (high potassium, rare-earth element, and phosphorus)-like gabbroic-basaltic breccia NWA 2727, although these grains are seemingly absent in other lunar meteorites. We interpret the origin of these grains as follows: alkaline water delivery to the Moon via carbonaceous chondrite collisions, fluid capture during impact-induced brecciation, moganite precipitation from the captured H₂O at pH 9.5 to 10.5 and 363 to 399 K on the sunlit surface, and meteorite launch from the Moon caused by an impact at 8 to 22 GPa and >673 K. On the subsurface, this captured H₂O may still remain as ice at estimated bulk content of >0.6 weight %. This indicates the possibility of the presence of abundant available water resources underneath local sites of the host bodies within the Procellarum KREEP and South Pole Aitken terranes.

Abstract P1-07-13: Obesity is associated with poor prognosis of Japanese breast cancer, especially in ER positive/HER2 negative subtype, which tendency is prominent

Introduction: Body mass index (BMI) is defined as a poor prognostic factor in breast cancer patients in western countries. Since the percentage of the overweight differs between Asian and western breast cancer patients, we do not know if breast cancer prognosis in Asia is related to obesity, the same as in western countries. Therefore, we have investigated the association between BMI and the prognosis of Japanese breast cancer patients.

Patients and Methods: This study is a retrospective analysis of the 1,924 primary Japanese female breast cancer patients with clinical stage I through III disease to have undergone surgery between January 2004 and December 2013 at the Hokkaido Cancer Center. The data of BMI were at the time of diagnosis, and stratified into 2 groups as non-Obese (BMI &lt; 25 kg/m2), Obese (BMI ≥ 25 kg/m2). The overall survival (OS) and disease-free survival (DFS) were compared between two BMI groups using the Kaplan-Meier method and Cox hazards model.

Results: The number of non-Obese group was 1,353 (70.3%) and Obese group was 571 (29.7%) of the 1,924 patients. Six hundred and thirty two patients were in premenopausal (32.8%), 1,289 were in postmenopausal (67.0%) and 3 were unknown. The median follow-up period was 73 months. Breast cancer recurred in 239 patients (12.2%), and 204 patients died. There were 110 cases of breast cancer-related death, 48 cases of non-breast cancer death, and 46 cases of unknown as the cause of death. Patients in Obese group had shown significantly poorer OS (adjusted hazard ratio (HR) = 1.68, 95% confidence interval (CI) = 0.45 to 0.79) and DFS (HR = 1.46, 95% CI = 1.16 to 1.82). As investigating by subtype analysis, a high BMI in ER positive/HER2 negative patients was associated with a significantly worse OS (HR = 2.04, 95% CI = 1.42 to 2.92) and significantly worse DFS (HR = 1.61, 95% CI = 1.23 to 2.11). On the other hand, there was no significant interaction found between the BMI and OS or DFS in ER negative/HER2 negative patients and HER2 positive patients. Subsequently, when analysis was limited to ER positive HER2 negative, there was a difference in the degree of association between obesity and prognosis due to the difference in menopause status. In premenopausal patients with ER positive/HER2 negative cancer, Obese group had significantly poorer OS (HR = 2.83, 95%CI = 1.32 to 5.88) and significantly poorer DFS (HR = 2.41, 95%CI = 1.41 to 3.99). In postmenopausal patients, Obese group patients had significantly poorer OS (HR = 1.71, 95%CI = 1.11 to 2.58) and poorer DFS (HR = 1.35, 95%CI = 0.98 to 1.86), however. The relevance was not so large compared with that in premenopausal patients.

Conclusion: Among Japanese breast cancer patients, Obese (BMI ≥ 25 kg/m2) was one of poor prognostic factors. Specifically, obesity was associated as an extremely strong prognostic factor in ER positive/HER2 negative premenopausal patients. Since hormone therapy has been practiced in almost all ER positive breast cancers, the relationship between hormonal therapy susceptibility and obesity is noticed not only in western patients but also in Asian patients.

Citation Format: Sato M, Terai S, Tachikawa H, Maeda H, Yamamoto M, Tomioka N, Watanabe K, Takahashi M. Obesity is associated with poor prognosis of Japanese breast cancer, especially in ER positive/HER2 negative subtype, which tendency is prominent [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-07-13.

Determination of hydrogen site and occupancy in hydrous Mg2SiO4 spinel by single-crystal neutron diffraction

A single-crystal neutron diffraction study was performed on hydrogen incorporation in ringwoodite, which is the most important host mineral of water in the Earth’s deep mantle. Its hydrogen incorporation mechanism, bonding geometry and occupancy at the relevant hydrogen site were unambiguously revealed.

Ringwoodite [(Mg,Fe²⁺)₂SiO₄ spinel] has been considered as one of the most important host minerals of water in the Earth’s deep mantle. Its extensive hydration was observed in high-pressure synthesis experiments and also by its natural occurrence. Water can dissolve into ringwoodite as structurally bound hydrogen cations by substituting other cations, although the hydrogen site and its occupancy remain unclear. In this study, neutron time-of-flight single-crystal Laue diffraction analysis was carried out for synthetic hydrous ringwoodite. Hydrogen cations were found only in the sites in MgO₆ octahedra in the ringwoodite structure, which compensated the reduced occupancies of both magnesium and silicon cations. The refined cation occupancies suggest that the most plausible hydration mechanism is that three hydrogen cations simultaneously occupy an MgO₆ octahedron, whereas four such hydrogenated octahedra surround a vacant SiO₄ tetrahedron.

The formation of peak rings in large impact craters

Large impacts provide a mechanism for resurfacing planets through mixing near-surface rocks with deeper material. Central peaks are formed from the dynamic uplift of rocks during crater formation. As crater size increases, central peaks transition to peak rings. Without samples, debate surrounds the mechanics of peak-ring formation and their depth of origin. Chicxulub is the only known impact structure on Earth with an unequivocal peak ring, but it is buried and only accessible through drilling. Expedition 364 sampled the Chicxulub peak ring, which we found was formed from uplifted, fractured, shocked, felsic basement rocks. The peak-ring rocks are cross-cut by dikes and shear zones and have an unusually low density and seismic velocity. Large impacts therefore generate vertical fluxes and increase porosity in planetary crust.

Quantitative analysis of hydrogen sites and occupancy in deep mantle hydrous wadsleyite using single crystal neutron diffraction

Evidence from seismological and mineralogical studies increasingly indicates that water from the oceans has been transported to the deep earth to form water-bearing dense mantle minerals. Wadsleyite [(Mg, Fe²⁺)₂SiO₄] has been identified as one of the most important host minerals incorporating this type of water, which is capable of storing the entire mass of the oceans as a hidden reservoir. To understand the effects of such water on the physical properties and chemical evolution of Earth's interior, it is essential to determine where in the crystal structure the hydration occurs and which chemical bonds are altered and weakened after hydration. Here, we conduct a neutron time-of-flight single-crystal Laue diffraction study on hydrous wadsleyite. Single crystals were grown under pressure to a size suitable for the experiment and with physical qualities representative of wet, deep mantle conditions. The results of this neutron single crystal diffraction study unambiguously demonstrate the method of hydrogen incorporation into the wadsleyite, which is qualitatively different from that of its denser polymorph, ringwoodite, in the wet mantle. The difference is a vital clue towards understanding why these dense mantle minerals show distinctly different softening behaviours after hydration.

Discovery of natural MgSiO3 tetragonal garnet in a shocked chondritic meteorite

MgSiO3 tetragonal garnet, which is the last of the missing phases of experimentally predicted high-pressure polymorphs of pyroxene, has been discovered in a shocked meteorite. The garnet is formed from low-Ca pyroxene in the host rock through a solid-state transformation at 17 to 20 GPa and 1900° to 2000°C. On the basis of the degree of cation ordering in its crystal structure, which can be deduced from electron diffraction intensities, the cooling rate of the shock-induced melt veins from ~2000°C was estimated to be higher than 10(3)°C/s. This cooling rate sets the upper bound for the shock-temperature increase in the bulk meteorite at ~900°C.

Abstract P5-08-15: Prognostic value of aldehyde dehydrogenase 1 (ALDH1) and tumor infiltrating lymphocytes (TIL) to predict the late recurrence in ER positive, HER2 negative breast cancer

Introduction: Aldehyde dehydrogenase 1(ALDH1) is known to be cancer stem cell marker. Also, tumor infiltrating lymphocytes (TILs) are known to be prognostic factor for triple negative breast cancer. It is reported that these factors have the correlation with chemosensitivity. Meanwhile, the late recurrence (LRec; 5 years after primary surgery) of ER positive breast cancer is the major problem. Significance of expressions of ALDH1 and TILs in primary tumor as predictive factors for late recurrence in ER positive, HER2 negative breast cancer is still unknown.

Methods: ER-positive, and HER2-negative breast cancer patients who underwent surgery or received neoadjuvant chemotherapy between January 2000 and December 2004 were registered from nine institutes belonging the Collaborative Study Group of Scientific Research of the Japanese Breast Cancer Society. For each LRec patient, approximately two matched control patients without relapse for more than ten years were selected. Expression of ALDH1 was assessed by immunohistochemistry. Positive ALDH1 was defined as tumor including more than 1% cancer cells with ALDH1 expression. TIL was assessed by single whole section according to Denkert's definition. A tumor showing high ki67 and/or low PgR expressions was categorized into Luminal B-like group.

Results: 639 patients (184 with early recurrence (ERec), 134 with LRec and 321 with no recurrence (NoRec)) were analyzed. The rates of positive ALDH1 in ERec, LRec and NoRec groups were 18%, 13% and 8%, respectively. ALDH1 positivity was significantly higher in ERec compared with NoRec group (p&lt;0.01). There was no significant difference between LRec and NoRec group (p=0.12). Positive ALDH1 showed significantly shorter DFS and OS in multivariate analyses (DFS: p=0.03, OS: p&lt;0.01). Especially, that was the significantly prognostic factor in the Luminal B like tumor with adjuvant or neoadjuvant chemotherapy (p=0.01), but not in those without any chemotherapy (p=0.53). High TILs in ERec, LRec and NoRec was 1.1%, 1.5% and 3.7%, respectively. There was no significant difference among three recurrent groups (p=0.13). High TILs was not significantly associated with DFS (p=0.09) and OS (p=0.72). However, there was significant correlation between High TILs and DFS in Luminal B like group (p=0.04) and ALDH1-negative group (p=0.02).

Conclusion: In ER-positive, and HER2-negative breast cancer, ALDH1 was an independent prognostic factor (a predictor of ERec, but not LRec). ALDH1 might be a predictor of benefit from chemotherapy in Luminal B like subtype. TILs was neither a predictor of ERec nor LRec. However, significance of TILs as prognostic factor might differ depending on subtypes and cancer stemness.

Citation Format: Miyoshi Y, Shien T, Ogiya A, Ishida N, Yamazaki K, Horii R, Horimoto Y, Masuda N, Yasojima H, Inao T, Osako T, Takahashi M, Tomioka N, Hagio K, Endo Y, Hosoda M, Yamashita H. Prognostic value of aldehyde dehydrogenase 1 (ALDH1) and tumor infiltrating lymphocytes (TIL) to predict the late recurrence in ER positive, HER2 negative breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P5-08-15.

Tritium in Japanese precipitation following the March 2011 Fukushima Daiichi Nuclear Plant accident

Tritium concentrations in Japanese precipitation samples collected after the March 2011 accident at the Fukushima Dai-ichi Nuclear Power Plant (FNPP1) were measured. Values exceeding the pre-accident background were detected at three out of seven localities (Tsukuba, Kashiwa and Hongo) southwest of the FNPP1 at distances varying between 170 and 220 km from the source. The highest tritium content was found in the first rainfall in Tsukuba after the accident; however concentrations were 500 times less than the regulatory limit for tritium in drinking water. Tritium concentrations decreased steadily and rapidly with time, becoming indistinguishable from the pre-accident values within five weeks. The atmospheric tritium activities in the vicinity of the FNPP1 during the earliest stage of the accident was estimated to be 1.5×10(3) Bq/m(3), which is potentially capable of producing rainwater exceeding the regulatory limit, but only in the immediate vicinity of the source.

Cesium Accumulation and Growth Characteristics of Rhodococcus erythropolis CS98 and Rhodococcus sp. Strain CS402

Growth and cesium accumulation characteristics of two cesium-accumulating bacteria isolated from soils were investigated. Rhodococcus erythropolis CS98 and Rhodococcus sp. strain CS402 accumulated high levels of cesium (approximately 690 and 380 mumol/g [dry weight] of cells or 92 and 52 mg/g [dry weight] of cells, respectively) after 24 h of incubation in the presence of 0.5 mM cesium. The optimum pH for cesium uptake by both Rhodococcus strains was 8.5. Rubidium and cesium assumed part of the role of potassium in the growth of both Rhodococcus strains. Potassium and rubidium inhibited cesium accumulation by these Rhodococcus strains. It is likely that both Rhodococcus strains accumulated cesium through a potassium transport system.

Trend of Stroke Incidence in a Japanese Population: Takashima Stroke Registry, 1990-2001

Background

In Japan, stroke mortality and incidence started to decline during the 1960s. The recent unfavourably diverging trends in risk factors make it uncertain whether the decline will continue. Few comprehensive stroke registries of long research duration exist in Japan to illustrate the trends in stroke incidence.

Objective

We examined 12-year stroke registration data to evaluate the current trend in a Japanese population.

Methods

Data were obtained from the Takashima Stroke Registry, covering approximately 55000 residents of Takashima County in central Japan. We calculated the age-adjusted stroke incidence rates (/100 000 person-years) and 95% confidence intervals for 1990–1992, 1993–1995, 1996–1998, and 1999–2001. We applied the direct method to adjust for the age distribution among the four periods. The incidence time trend was determined by calculating the average annual change across the study years using negative binomial regression analysis.

Results

There were 1453 (men: 771 and women: 682) registered first-ever stroke cases during 1990–2001. The diagnosis was established by neuro-imaging in 93·6% of the cases. The average age was 69·4 years in men and 74·2 years in women. The age-adjusted incidence rates of stroke across the four observation periods were 143·1 (confidence interval: 127·4-158·8) in 1990–1992, 147·4 (confidence interval: 131·9–162·8) in 1993–1995, 120·4 (confidence interval: 106·7–134·0) in 1996–1998, and 122·9 (confidence interval: 109·6–136·2) in 1999–2001. The stroke incidence across the study years showed an insignificant time trend, with an average annual change of −0·33% (confidence interval: −2·44 to 1·78) per year. Similar trends were observed for both men and women and stroke subtypes.

Conclusions

The previously reported declining trend in stroke incidence may have levelled off or slowed down considerably in the Japanese population.

Novel risk stratification of patients with neuroblastoma by genomic signature, which is independent of molecular signature

Human neuroblastoma remains enigmatic because it often shows spontaneous regression and aggressive growth. The prognosis of advanced stage of sporadic neuroblastomas is still poor. Here, we investigated whether genomic and molecular signatures could categorize new therapeutic risk groups in primary neuroblastomas. We conducted microarray-based comparative genomic hybridization (array-CGH) with a DNA chip carrying 2464 BAC clones to examine genomic aberrations of 236 neuroblastomas and used in-house cDNA microarrays for gene-expression profiling. Array-CGH demonstrated three major genomic groups of chromosomal aberrations: silent (GGS), partial gains and/or losses (GGP) and whole gains and/or losses (GGW), which well corresponded with the patterns of chromosome 17 abnormalities. They were further classified into subgroups with different outcomes. In 112 sporadic neuroblastomas, MYCN amplification was frequent in GGS (22%) and GGP (53%) and caused serious outcomes in patients. Sporadic tumors with a single copy of MYCN showed the 5-year cumulative survival rates of 89% in GGS, 53% in GGP and 85% in GGW. Molecular signatures also segregated patients into the favorable and unfavorable prognosis groups (P=0.001). Both univariate and multivariate analyses revealed that genomic and molecular signatures were mutually independent, powerful prognostic indicators. Thus, combined genomic and molecular signatures may categorize novel risk groups and confer new clues for allowing tailored or even individualized medicine to patients with neuroblastoma.

Mineralogy and petrology of comet 81P/Wild 2 nucleus samples

The bulk of the comet 81P/Wild 2 (hereafter Wild 2) samples returned to Earth by the Stardust spacecraft appear to be weakly constructed mixtures of nanometer-scale grains, with occasional much larger (over 1 micrometer) ferromagnesian silicates, Fe-Ni sulfides, Fe-Ni metal, and accessory phases. The very wide range of olivine and low-Ca pyroxene compositions in comet Wild 2 requires a wide range of formation conditions, probably reflecting very different formation locations in the protoplanetary disk. The restricted compositional ranges of Fe-Ni sulfides, the wide range for silicates, and the absence of hydrous phases indicate that comet Wild 2 experienced little or no aqueous alteration. Less abundant Wild 2 materials include a refractory particle, whose presence appears to require radial transport in the early protoplanetary disk.

Comet 81P/Wild 2 Under a Microscope

The Stardust spacecraft collected thousands of particles from comet 81P/Wild 2 and returned them to Earth for laboratory study. The preliminary examination of these samples shows that the nonvolatile portion of the comet is an unequilibrated assortment of materials that have both presolar and solar system origin. The comet contains an abundance of silicate grains that are much larger than predictions of interstellar grain models, and many of these are high-temperature minerals that appear to have formed in the inner regions of the solar nebula. Their presence in a comet proves that the formation of the solar system included mixing on the grandest scales.

Striped iron zoning of olivine induced by dislocation creep in deformed peridotites

Deformation of solid materials affects not only their microstructures, but also their microchemistries. Although chemical unmixing of initially homogeneous multicomponent solids is known to occur during deformation by diffusion creep, there has been no report on their chemical zoning due to deformation by dislocation creep, in either natural samples or laboratory experiments. Here we report striped iron zoning of olivine ((Mg,Fe)2SiO4) in deformed peridotites, where the iron concentration increases at subgrain boundaries composed of edge dislocations. We infer that this zoning is probably formed by alignment of edge dislocations dragging a so-called Cottrell 'atmosphere' of solute atoms (iron in this case) into subgrain boundaries during deformation of the olivine by dislocation creep. We have found that the iron zoning does not develop in laboratory experiments of high strain rates where dislocations move too fast to drag the Cottrell atmosphere. This phenomenon might have important implications for the generation of deep-focus earthquakes, as transformation of olivine to high-pressure phases preferentially occurs in high-iron regions, and therefore along subgrain boundaries which would be preferentially aligned in plastically deformed mantle peridotites.

Discovery of Novel Aldose Reductase Inhibitors Using a Protein Structure-Based Approach: 3D-Database Search Followed by Design and Synthesis

Aldose reductase (AR) has been implicated in the etiology of diabetic complications. Due to the limited number of currently available drugs for the treatment of diabetic complications, we have carried out structure-based drug design and synthesis in an attempt to find new types of AR inhibitors. With the ADAM&EVE program, a three-dimensional database (ACD3D) was searched using the ligand binding site of the AR crystal structure. Out of 179 compounds selected through this search followed by visual inspection, 36 compounds were purchased and subjected to a biological assay. Ten compounds showed more than 40% inhibition of AR at a 15 microg/mL concentration. In a subsequent lead optimization, a series of analogues of the most active compound were synthesized based on the docking mode derived by ADAM&EVE. Many of these congeners exhibited higher activities compared to the mother compound. Indeed, the most potent, synthesized compound showed an approximately 20-fold increase in inhibitory activity (IC(50) = 0.21 vs 4.3 microM). Furthermore, a hydrophobic subsite was newly inferred, which would be useful for the design of inhibitors with improved affinity for AR.

Identification and characterization of a 500-kb homozygously deleted region at 1p36.2-p36.3 in a neuroblastoma cell line

Loss of heterozygosity of the distal region of chromosome 1p where tumor suppressor gene(s) might harbor is frequently observed in many human cancers including neuroblastoma (NBL) with MYCN amplification and poor prognosis. We have identified for the first time a homozygously deleted region at the marker D1S244 within the smallest region of overlap at 1p36.2-p36.3 in two NBL cell lines, NB-1 and NB-C201 (MASS-NB-SCH1), although our genotyping has suggested the possibility that both lines are derived from the same origin. The 800-kb PAC contig covering the entire region of homozygous deletion was made and partially sequenced (about 60%). The estimated length of the deleted region was 500 kb. We have, thus far, identified six genes within the region which include three known genes (DFF45, PGD, and CORT) as well as three other genes which have been reported during processing our present project for the last 3(1/2) years (HDNB1/UFD2, KIAA0591F/KIF1B-beta, and PEX14). They include the genes related to apoptosis, glucose metabolism, ubiquitin-proteasome pathway, a neuronal microtubule-associated motor molecule and biogenesis of peroxisome. At least three genes (HDNB1/UFD2, KIAA0591F/KIF1B-beta, and PEX14) were differentially expressed at high levels in favorable and at low levels in unfavorable subsets of primary neuroblastoma. Since the 1p distal region is reported to be imprinted, those differentially expressed genes could be the new members of the candidate NBL suppressor, although RT-PCR-SSCP analysis has demonstrated infrequent mutation of the genes so far identified. Full-sequencing and gene prediction for the region of homozygous deletion would elucidate more detailed structure of this region and might lead to discovery of additional candidate genes. Oncogene (2000) 19, 4302 - 4307

Neocortical origin and tangential migration of guidepost neurons in the lateral olfactory tract

The early-generated neurons designated as lot cells specifically mark the future site of the lateral olfactory tract (LOT) and guide LOT axons. We investigated the mechanism of how lot cells develop and get localized in the LOT position. Lot cells differentiated from neuroepithelial cells in all regions of the neocortex but not from those in the ganglionic eminence in culture. Cell tracing analyses demonstrated that lot cells generated from the neocortex subsequently followed a tangential migration stream ventrally toward the LOT position. Mutant mouse embryos lacking the function of transcription factor Gli3 showed disturbances of the migration stream and translocation of lot cells in the dorsal telencephalon. These results reveal a new type of neuronal migration in the telencephalon and introduce an unexpected dramatic feature of the earliest regionalization of the telencephalon.

Identification of the full-length KIAA0591 gene encoding a novel kinesin-related protein which is mapped to the neuroblastoma suppressor gene locus at 1p36.2

The distal region of a short arm of chromosome 1p is frequently deleted in many human cancers including neuroblastoma (NBL), in which it has been narrowed down to the smallest region of overlap between D1S244 and D1S214 (approximately 7 cM). During the search for the candidate tumor suppressor genes mapped within the region, we found the KIAA0591 gene which encoded a new human kinesin-related protein with a homology to human axonal transporter of synaptic vesicles (ATSV). The kinesin is an intracellular motor protein and often associated with neuronal differentiation and survival. Here we identified a complete open reading frame of the KIAA0591 gene by screening a cDNA library derived from human substantia nigra. The KIAA0591 protein contains a possible pleckstrin homology (PH) domain at its carboxy-terminus. However, it did not possess a force-generating motor domain which is well conserved among kinesin superfamily members (KIFs). Northern blot analysis demonstrated that KIAA0591 mRNA was preferentially expressed in both adult and fetal brains, kidney, skeletal muscle and pancreas. KIAA0591 was expressed in favorable NBLs at higher levels than in unfavorable NBLs, although RT-PCR SSCP analysis showed no mutation within the coding region of the KIAA0591 gene, when 8 neuroblastoma tissues and 15 neuroblastoma-derived cell lines were examined. Thus, the full-length KIAA0591 gene may be a novel member of human KIF superfamily which lacks motor domain and might function as a tumor suppressor in an epigenetic but not a classic Knudson's manner.

Successful simultaneous operation of concomitant early gastric cancer, transverse colon cancer, and a common iliac artery aneurysm

In an 83-year-old Japanese man, concomitant bleeding colon cancer, early gastric cancer, and an expanding right common iliac artery aneurysm were evident. The patient underwent an artificial graft implantation, partial gastrectomy, and transverse colectomy, simultaneously. To protect against graft infection, the aneurysm was resected first, and then the retroperitoneum was tightly closed to isolate the graft from the peritoneal cavity. The postoperative course was uneventful, except for symptoms of temporary delirium. Recently, simultaneous surgery for concomitant abdominal aortic aneurysms and early gastric cancer has been commonly performed in Japan because the contamination of the peritoneal cavity during a gastrectomy is thought to be less severe than that during lower abdominal surgery. However, the positive rate for bacterial culture in colorectal resections is virtually the same as that in gastrectomies. Moreover, the incidence of graft infection is substantially lower than the positive rate for bacterial culture in surgery for aneurysms. Some surgeons object to a simultaneous resection due to fear of graft infection, but even the presence of infectious organisms does not always result in graft infection. The present case illustrates the benefits of a simultaneous operation for both an aneurysm and gastrointestinal malignancy.

Gastric exclusion for unresectable gastric cancer

BACKGROUND/AIMS

Conventional gastrojejunostomy is sometimes performed for unresectable gastric cancer, but it is not fully effective. To improve the patient's quality of life, we performed gastric exclusion.

METHODOLOGY

Twenty-seven patients who received gastrojejunostomy (11 conventional, 16 gastric exclusion) were retrospectively examined as to post-operative quality of life and outcome.

RESULTS

No stomal strictures were observed, and gastrointestinal bleeding was significantly reduced in the gastric exclusion group. These advantages enabled the gastric exclusion group to achieve better quality of life, as indicated by longer oral intake (244 days vs. 98 days) and home stay (211 days vs. 91 days). The prognosis also improved. The 50% survival period in the gastric exclusion group was 229 days, whereas, that of the conventional gastrojejunostomy group was 131 days.

CONCLUSIONS

The quality of life and prognosis of the gastric exclusion group significantly improved, and we believe that the improvement of the quality of life yielded a better prognosis. We recommend gastric exclusion as a standard procedure for unresectable gastric cancer.

Synthesis, computer modeling and biological evaluation of novel protein kinase C agonists based on a 7-membered lactam moiety

4-Hydroxymethyl-5a-methyl-1,3,4,5,5a beta,6,7,8,9,9a alpha-decahydro-2H-benz[d]azepin-2-ones (4-12), which were designed to mimic the biologically active conformation of teleocidins and benzolactams, were synthesized and evaluated for the ability to compete with [3H]phorbol 12,13-dibutyrate in a PKC delta binding assay. Among the compounds, 10-12 showed potent binding affinity, with inhibition constants (Ki) of low nanomolar order. Computational docking simulation also indicates that the relative positions of the hydrogen-bonding sites and hydrophobic regions of the compounds are well matched to the PKC delta binding site.

Induction and enhancement of stress proteins in a trichloroethylene-degrading methanotrophic bacterium, Methylocystis sp. M

The responses of the trichloroethylene-degrading bacterium Methylocystis sp. M to six different water-pollutants, carbon starvation, and temperature-shock (heat and cold) were examined using 2-dimensional gel electrophoresis. Twenty-eight polypeptides were induced, and these stress-induced proteins were classified into three groups. Some of the chemically induced proteins were the same as those induced by carbon starvation and temperature-shock. Two of the polypeptides were induced by trichloroethylene. Trichloroethylene-stress protein synthesis required 1-2 h at a concentration of trichloroethylene that had no effect on growth. Furthermore, 25 stress-enhanced polypeptides were observed, and one of these was enhanced by trichloroethylene. Based on these results, we discuss applications of chemical-stress induction of proteins to establish effective bioremediation and bioassay by methanotrophs.

Clarification of the binding mode of teleocidin and benzolactams to the Cys2 domain of protein kinase Cdelta by synthesis of hydrophobically modified, teleocidin-mimicking benzolactams and computational docking simulation

Phorbol esters (12-O-tetradecanoylphorbol 13-acetate; TPA) and teleocidins are known to be potent tumor promoters and to activate protein kinase C (PKC) by binding competitively to the enzyme. The relationship between the chemical structures and the activities of these compounds has attracted much attention because of the marked structural dissimilarities. The benzolactam 5, with an eight-membered lactam ring and benzene ring instead of the nine-membered lactam ring and indole ring of teleocidins, reproduces the active ring conformation and biological activities of teleocidins. Herein we describe the synthesis of benzolactams with hydrophobic substituents at various positions. Structure-activity data indicate that the existence of a hydrophobic region between C-2 and C-9 and the steric factor at C-8 play critical roles in the appearance of biological activities. We also computationally simulated the docking of teleocidin and the modified benzolactam molecules to the Cys2 domain structure observed in the crystalline complex of PKCdelta with phorbol 13-acetate. Teleocidin and benzolactams fitted well into the same cavity as phorbol 13-acetate. Of the three functional groups hydrogen-bonding to the protein, two hydrogen-bonded with protein atoms in common with phorbol 13-acetate, but the third one hydrogen-bonded with a different protein atom from that in the case of phorbol 13-acetate. The model explains well the remarkable difference in activity between 5 and its analogue having a bulky substituent at C-8.

Proton transfer in benzyl alcohol dehydrogenase during catalysis: alternate proton-relay routes

His51 in horse liver alcohol dehydrogenase (ADHE) has been proposed to act as a proton donor/acceptor in the NAD+/NADH-dependent oxidation/reduction of alcohol/aldehyde. The residue corresponding to His51 of ADHE is Val51 (Val45 in the protein sequence) in benzyl alcohol dehydrogenase (BADH) encoded by TOL plasmid pWW0. The 3-D structure of BADH modeled from the crystal structure of ADHE suggests that His47 (His41 in the protein sequence, corresponding to Arg47 in ADHE) of BADH would play the role of His51 in ADHE. To test this hypothesis, mutants of BADH, in which His47 was replaced by Gln(His47Gln) and/or Val51 was replaced by His (Val51His), were constructed. The kcat/K(m) value of the His47Gln mutant for benzyl alcohol was 125-fold lower than that of wild-type BADH, while the kcat/K(m) value of the His47Gln/Val51His double mutant was 12-fold higher than that of the His47Gln mutant. The kcat/K(m) value of the His47Gln mutant increased with increasing concentration of exogenous amines. These results suggest that His47 in wild-type BADH, exogenous amines in the His47Gln mutant, and His51 in the double mutant act as a general base catalyst during alcohol oxidation.

Indications for peripartum aortic pressure monitoring in Takayasu's disease. A patient with past history of intrapartum cerebral hemorrhage

We describe a successful delivery by prophylactic cesarean section in a patient with Takayasu's disease who had a previous history of intrapartum cerebral hemorrhage during vaginal delivery. Aortography showed occlusion of the common carotid, subclavian and vertebral arteries on the left side, severe narrowing of the right subclavian artery, and moderate narrowing of the entire abdominal aorta. Blood pressure was managed by monitoring central aortic pressure at the thoracic aorta. During the peripartum course, we recommend monitoring the central aortic pressure in patients with Takayasu's disease in whom accurate blood pressure readings can not be obtained in any extremity.

[Prognosis and preoperative imaging of patients with small hepatocellular carcinoma]

We conducted a retrospective study on the relation of the preoperative imaging patterns to the prognosis of patients with small HCC after hepatectomy. Forty patients with small HCC less than 2 cm in diameter without vascular invasion were enrolled in this study. There were no significant differences in the signal intensity of T1WI on MRI, and angiographic findings such as neo-vascularity or tumor stain. Ultrasonographical images of the internal of tumor were classified into two groups. Six cases with homogeneous pattern were significantly worse in cumulative survival rate than 28 cases with heterogeneous pattern (p = 0.0012). The same results were obtained with respect to limitation of cases treated by relative curative operation (p = 0.0041). It was concluded that histopathological grading and malignant potential of small HCC could be evaluated by classification of the pattern of internal ultrasonographical images, and complete locoregional therapy, and that intense course observation for cases with ultrasonographical homogeneous pattern would be important.

Natural (Mg,Fe)SiO3-ilmenite and -perovskite in the Tenham meteorite

The minerals (Mg,Fe)SiO3-ilmenite and -perovskite were identified in the shock-induced veins in the Tenham chondritic meteorite. Both phases are inferred to have transformed from pyroxene at high pressures and temperatures by shock metamorphism. Columnar-shaped ilmenite grains, one of two types of morphologies, have a topotaxial relationship with neighboring pyroxene grains, indicating shear transformation. Granular-shaped perovskite grains showed a diffraction pattern consistent with orthorhombic perovskite, but these grains were not stable under the electron beam irradiation and became amorphous. The higher iron concentration in both phases compared with those experimentally reported may suggest their metastable transition from enstatite because of shock compression.

[Clinicopathological study on early recurrent hepatoma and its treatment]

Early Recurrence of Hepatoma: PCNA Labeling Index and DNA Ploidy Pattern Sixty-four cases of recurrent hepatocellular carcinoma (HCC) after hepatectomy were divided into two groups; E-group with recurrence within one year, and L-group with recurrence after 1 year. Clinicopathological features and surgical curability were the same in both groups. E-group had significantly higher positive rates of portal invasion, intrahepatic metastasis and rate of patients with more than 40% on PCNA labeling index. While the similar recurrence mode and the same treatment modalities were done, cumulative survival rates after recurrence in E-group had a poorer prognosis than L-group. These results suggest the possibility of lower response for the treatment on the recurrent lesion would be manifest in the E-group. New modalities for prevention of early recurrence of HCC after resection should be developed.

Lead discovery of inhibitors of the dihydrofolate reductase domain of Plasmodium falciparum dihydrofolate reductase-thymidylate synthase

A three-dimensional structure model of the dihydrofolate reductase (DHFR) domain of the bifunctional DHFR-thymidylate synthase of Plasmodium falciparum was used as a basis for computational screening of commercially available compounds for candidate inhibitors. Compounds which can stably dock to the model with strong ionic hydrogen bonds via protonation by an aspartic acid residue at the bottom of the active site were identified through docking simulation. Among compounds thus identified, 21 were assayed for inhibitory activity towards the recombinant DHFR domain. Two compounds, 2-amino-1,4-dihydro-4,4,7,8-tetramethyl-s-triazino(1,2-a)benzimida zole and Trp-P-2, inhibited the recombinant P. falciparum DHFR domain with Ki values of 0.54 and 8.7 microM, respectively. Kinetic analysis showed that these compounds competitively inhibited the enzyme with respect to the substrate dihydrofolate. These findings support the validity of both the modeled structure and the docking results. Furthermore, these compounds serve as leads for developing new DHFR inhibitors, since their skeletal structures are different from any of known DHFR inhibitors. This paper also reveals a new biological activity of Trp-P-2, a potent mutagen.

HLA-DR2 antigen linkage in patients with apical hypertrophic cardiomyopathy in Japan

Apical hypertrophic cardiomyopathy, a very common disorder in Japan, is characterized by giant negative T waves on the electrocardiogram and abnormal apical hypertrophy on the ventriculogram. This histocompatibility complexes (HLA-A, -B, -C, -DR) of 20 unrelated patients with apical hypertrophic cardiomyopathy (18 male, 2 female) were examined. There was no significant difference in the frequency of HLA-A, -B, -C antigens between patients and controls (n = 100). However, HLA-DR 2 was more frequent in patients with apical hypertrophic cardiomyopathy (65.0%) than controls (33.0%) (p < 0.01). We conclude that apical hypertrophic cardiomyopathy might be associated with genes in the HLA-DR region and that genetic factors linked to HLA play a role in the pathogenesis of this disease.

Myocardial contusion caused by a baseball

Myocardial contusion is a rare type of sports injury. We report a case of myocardial contusion caused by a baseball. In this patient, arrhythmias were induced by an exercise test 1 week after injury. That patients with myocardial contusion but without arrhythmias at rest need to be treated carefully is emphasized.

[The effects of preoperative transcatheter arterial chemoembolization (TAE) for the recurrence of hepatocellular carcinoma (HCC) from the viewpoint of consecutive tumor necrosis effect]

From 1990 to 1994, seventy-seven patients with HCC below 10 cm in tumor diameter underwent hepatic resections after TAE. They were divided into two groups: group C, complete necrosis (over 90% histologically at the maximum cutting surface of the specimen): group I, incomplete necrosis (under 90%). There were no significant differences in clinical background of patients, histopathological features and total disease-free survival rate (DFR) between the two groups. Nevertheless, DFR of patients in group C was significantly better than that of patients in group I, limiting the patients for curative resection. It was suggested that the recurrence of HCC after resection might be inhibited by curative operation following preoperative TAE with complete necrosis of tumor.

[Role of reservoirs in intraarterial chemotherapy for recurrent hepatocellular carcinoma after hepatectomy]

We conducted a retrospective study on the role of reservoirs in intraarterial chemotherapy for recurrent hepatocellular carcinoma (HCC) after hepatectomy. Ninety-two out of 170 patients with HCC who underwent hepatectomy from 1987 to 1992 in our institute were enrolled in this study. HCC recurred in 55 patients. A rate of good patency of the catheter of the reservoir at the time of recurrence was found in 72.7% of the patients. Transcatheter arterial embolization (TAE) for recurrent tumor was not feasible in 3 patients, because of occlusion of the hepatic artery (3.3% of patients with reservoir, 5.5% of patients with recurrence). Eleven patients were treated by intraarterial chemotherapy using the reservoir and TAE or TAE and PEIT (group R), and 11 patients were treated only with TAE and/or PEIT (group NR). Although there were no significant differences between the two groups in the number of recurrent lesions and operative procedures, tumor-free interval was shorter in group R. Cumulative survival rates after recurrence were not significant. The frequency of TAEs was lower in group R, which shortened the hospitalization for postrecurrence therapy. Thus, intraarterial chemotherapy using reservoir contributed to improvement of the quality of life of patients with recurrent HCC.

Inhibition mechanisms of staurosporine and H7 to cAMP-dependent protein kinase through docking study

Inhibition mechanisms of staurosporine and H7 to cAMP-dependent protein kinase have been investigated through docking studies. For each molecule, the energetically most stable docking model was searched by using the conformationally flexible automatic docking program ADAM without any presumptions. The results explain well the observation that staurosporine does not bind to the enzyme competitively with H7, even though the two compounds competitively inhibit ATP binding.

[Advantages and disadvantages of the intraarterial chemotherapy using a reservoir as postoperative adjuvant therapy for hepatocellular carcinoma]

We conducted a retrospective study on the efficacy and disadvantages of intraarterial chemotherapy using a reservoir (ICUR), as postoperative adjuvant therapy for hepatocellular carcinoma (HCC). One hundred and seventy HCC patients who underwent hepatectomy since 1987 to 1992 in our institute were enrolled in this study. Ninety-two patients were postoperatively treated with ICUR (group R), and seventy-eight patients without it (group N). There were no significant differences between the two groups in the preoperative evaluations of the characteristics of patients, tumors, and operative procedures. Although statistical significances were not found, disease-free rates within 1 year and cumulative survival rates appeared to be higher in group R than in group N. Patency of the catheter of reservoirs at one and two years were maintained in 80.3 and 44.1% of the patients, respectively. HCC recurred after an occlusion of the reservoir in 18 patients. In four out of these 18 patients, transcatheter arterial embolization (TAE) for recurrent tumors was not feasible, because of occlusion of the hepatic artery. TAEs for recurrent lesions would have been impossible in about 10% of all patients treated with ICUR. Thus, both the advantages and disadvantages should be taken into consideration on the indication of ICUR, and the maintainance of the catheter is important for successful ICUR.

Rational automatic search method for stable docking models of protein and ligand

An efficient automatic method has been developed for docking a ligand molecule to a protein molecule. The method can construct energetically favorable docking models, considering specific interactions between the two molecules and conformational flexibility in the ligand. In the first stage of docking, likely binding modes are searched and estimated effectively in terms of hydrogen bonds, together with conformations in part of the ligand structure that includes hydrogen bonding groups. After that part is placed in the protein cavity and is optimized, conformations in the remaining part are also examined systematically. Finally, several stable docking models are obtained after optimization of the position, orientation and conformation of the whole ligand molecule. In all the screening processes, the total potential energy including intra- and intermolecular interaction energy, consisting of van der Waals, electrostatic and hydrogen bonding energies, is used as the index. The characteristics of our docking method are high accuracy of the results, fully automatic generation of models and short computational time. The efficiency of the method was confirmed by four docking trials using two enzyme systems. In two attempts to dock methotrexate to dihydrofolate reductase and 2'-GMP to ribonuclease T1, the exact structures of complexes in crystals were reproduced as the most stable docking models, without any assumptions concerning the binding modes and ligand conformations. The most stable docking models of dihydrofolate and trimethoprim, respectively, to dihydrofolate reductase were also in good agreement with those suggested by experiment. In all test cases, it was shown that our method can accurately predict the correct docking structures, discriminating the correct model from incorrect ones. The efficiency of our method was further tested from the viewpoint of ability to predict the relative stability of the docking structures of two triazine derivatives to dihydrofolate reductase. Our docking method provides a useful tool for rational drug design and investigations of biochemical reaction mechanisms.

GREEN: a program package for docking studies in rational drug design

A program package, GREEN, has been developed that enables docking studies between ligand molecules and a protein molecule. Based on the structure of the protein molecule, the physical and chemical environment of the ligand-binding site is expressed as three-dimensional grid-point data. The grid-point data are used for the real-time evaluation of the protein-ligand interaction energy, as well as for the graphical representation of the binding-site environment. The interactive docking operation is facilitated by various built-in functions, such as energy minimization, energy contribution analysis and logging of the manipulation trajectory. Interactive modeling functions are incorporated for designing new ligand molecules while considering the binding-site environment and the protein-ligand interaction. As an example of the application of GREEN, a docking study is presented on the complex between trypsin and a synthetic trypsin inhibitor. The program package will be useful for rational drug design, based on the 3D structure of the target protein.