RIB induced reactions: Studying astrophysical reactions with low-energy RI beam at CRIB

Astrophysical reactions involving radioactive isotopes (RI) often play an important role in high-temperature stellar environments. The experimental studies on the reaction rates for those are still limited mainly due to the technical difficulties in producing high-quality RI beams. A direct measurement of those reactions would be still challenging in many cases, however, we can make a reliable evaluation of the reaction rates by an indirect method or by studying the resonance prorerties. Here we ntroduce recent examples of experimental studies on such RI-involving astrophysical reactions, performed at Center for Nuclear Study, the University of Tokyo, using the low-energy RI beam separator CRIB. One is for the neutron-induced destruction reactions of 7Be in the Big-Bang nucleosynthesis, and the other is the study on the 22Mg(α, p) reaction relevant in X-ray bursts, which was performed with the resonant scattering method from the inverse reaction channel.

Experimental studies on astrophysical reactions at the low-energy RI beam separator CRIB

Experimental studies on astrophysical reactions involving radioactive isotopes (RI) often accompany technical challenges. Studies on such nuclear reactions have been conducted at the low-energy RI beam separator CRIB, operated by Center for Nuclear Study, the University of Tokyo. We discuss two cases of astrophysical reaction studies at CRIB; one is for the 7Be+n reactions which may affect the primordial 7Li abundance in the Big-Bang nucleosynthesis, and the other is for the 22Mg(α, p) reaction relevantin X-raybursts.

Effect of proton pump inhibitors on the development of hypomagnesemia induced by panitumumab

Panitumumab, a therapeutic agent for unresectable advanced/recurrent colorectal cancer, is a human IgG2 monoclonal antibody that binds to and inhibits the activity of the epidermal growth factor receptor (EGFR). The onset of hypomagnesemia is a known side effect of anti-EGFR inhibitors, including panitumumab, and it is thought that inhibition of reabsorption of Mg in renal tubules is one of the causes. In addition, recent reports have shown that long-term administration of proton pump inhibitors (PPIs) reduces serum magnesium levels. Therefore, in this study, 102 patients who received oral PPIs treated with panitumumab were classified into a PPI combination group and a PPI non-combination group, and the effect of PPIs on the development of grade 2 or higher hypomagnesemia was investigated. The incidence of hypomagnesemia in the PPI combination group (46.9%, 15/32) was higher than that in the PPI non-combination group (25.7%, 18/70). A comparison of the backgrounds of the two groups of patients showed a significant difference in serum albumin levels. PPI administration was significantly associated with panitumumab-induced hypomagnesemia development when adjusted for known risk factors, serum albumin level, renal function, and oral magnesium oxide tablets in Cox proportional hazards regression analysis (hazard ratio 2.09; 95% confidence interval 1.03-4.22; P =0.040). These results indicate that detailed monitoring of serum magnesium levels is recommended for patients treated with panitumumab and co-administration of PPIs.

Feasibility and safety of early initiation of a PCSK9 (proprotein convertase subtilisin/kexin type 9) inhibitor in patients with acute myocardial infarction undergoing primary PCI

Background

Recent ESC/EAS Guidelines for the management of dyslipidemia stated that the treatment goal of LDL cholesterol (LDL-C) in very high-risk patients is less than 55mg/dl. PCSK9 inhibitors in addition to strong statins could be a useful strategy for rapid and aggressive lowering of LDL-C. However, the feasibility and safety of early initiation of a PCSK9 inhibitor for AMI patients undergoing primary PCI remain unclear.

Objectives

We examined the effects of early initiation of a PCSK9 inhibitor, evolocumab, on lipid profile and inflammatory markers and its safety in AMI patients undergoing primary PCI.

Methods

This study is a single center, randomized, controlled trial involving 102 patients hospitalized for AMI. The patients were randomly assigned 1:1 to the evolocumab group and the control group. Evolocumab (140 mg) was subcutaneously injected within 24 hours after PCI and then every two weeks. All patients received pitavastatin (2mg/day) in addition to the allocated treatment. The primary endpoints were changes in lipid profile and inflammatory markers from baseline to 4 weeks.

Results

102 patients were enrolled between October 2017 and December 2019. 89 patients were ST-segment elevation myocardial infarction (STEMI), 13 patients were non-STEMI. Primary PCI was successfully performed in all patients. 76 patients were statin-naïve. 2 patients were excluded from analyses because they died severe heart failure in acute phase. Finally, 100 patients (evolocumab; n=51 and control; n=49) were analyzed. Baseline LDL-C was 121.6±30.3 mg/dl in the evolocumab group and 124.7±33.6 mg in the control group. Change in LDL-C from the baseline to 4 weeks was −92.4±32.4 mg/dl (−75%) in the evolocumab group and −44.8±32.1 mg/dl (−33.1%) in the control group (mean difference; 47.6mg/dl, 95% CI; 34.8 to 60.4 mg/dl, p<0.001). LDL-C <70mg/dl at 4 weeks was achieved in 96.0% of the evolocumab group as compared with 26.5% of the control group. Further, in the evolocumab group. LDL <55mg/dl was achieved in 92.1% at 2 weeks and 92.1% at 4 weeks. Regarding inflammatory markers, there were no significant difference in change in high-sensitivity C-reactive protein (p=0.49) and tumor necrosis factor-alpha (p=0.63) between two groups even after adjustment of baseline value. No adverse event associated with evolocumab was observed during this study.

Conclusion

In patients with AMI undergoing primary PCI, early initiation of evolocumab rapidly reduced LDL-C without no adverse event, and achieved LDL-C<55mg/dl in most patients within 2 weeks. Early administration of a PCSK9 inhibitor combined with a strong statin could be a feasible and safe treatment for AMI patients undergoing PCI.

Funding Acknowledgement

Type of funding source: None

Precise absolute Seebeck coefficient measurement and uncertainty analysis using high-Tc superconductors as a reference

The intrinsic properties of superconductors enable the direct determination of the absolute Seebeck coefficient at low temperature due to the disappearance of the Seebeck effect to obey the Meissner effect. We report a precision absolute Seebeck coefficient measurement for the fine Pt sample determined using the high-Tc YBa₂Cu₃O_7-x (YBCO) superconductor as a reference and an analysis of the measurement uncertainty. To make a precision measurement and aid in the verification of the uncertainty components, we developed a cryostat system that enables temperature control in a stable manner. The expected performance of the reference superconductor yielded a zero value well below Tc, which was validated by a superconductor-superconductor thermocouple experiment. Uncertainty analysis shows that the main limiting factor for this measurement is the accuracy of the temperature difference measurement using the resistance temperature sensors, along with its analog noise. We obtained values of S = 5.6 ± 0.2 µV/K with a relative expanded uncertainty of 3% at 80 K and precisely compared the Pt value with that determined by the high-Tc Bi₂Sr₂Ca₂Cu₃O_8+δ (Bi-2223) superconductor, which has a higher Tc. We found that there was no difference between the Seebeck coefficient values obtained from the YBCO and Bi-2223 references up to its Tc within the expanded measurement uncertainties of 0.3 µV/K (2σ). These results provide accurate validation that the high-Tc superconductor is a useful reference up to the liquid nitrogen temperature.

Fermiology and Superconductivity of Topological Surface States in PdTe_{2}

We study the low-energy surface electronic structure of the transition-metal dichalcogenide superconductor PdTe_{2} by spin- and angle-resolved photoemission, scanning tunneling microscopy, and density-functional theory-based supercell calculations. Comparing PdTe_{2} with its sister compound PtSe_{2}, we demonstrate how enhanced interlayer hopping in the Te-based material drives a band inversion within the antibonding p-orbital manifold well above the Fermi level. We show how this mediates spin-polarized topological surface states which form rich multivalley Fermi surfaces with complex spin textures. Scanning tunneling spectroscopy reveals type-II superconductivity at the surface, and moreover shows no evidence for an unconventional component of its superconducting order parameter, despite the presence of topological surface states.

Ubiquitous formation of bulk Dirac cones and topological surface states from a single orbital manifold in transition-metal dichalcogenides

Transition-metal dichalcogenides (TMDs) are renowned for their rich and varied bulk properties, while their single-layer variants have become one of the most prominent examples of two-dimensional materials beyond graphene. Their disparate ground states largely depend on transition metal d-electron-derived electronic states, on which the vast majority of attention has been concentrated to date. Here, we focus on the chalcogen-derived states. From density-functional theory calculations together with spin- and angle-resolved photoemission, we find that these generically host a co-existence of type-I and type-II three-dimensional bulk Dirac fermions as well as ladders of topological surface states and surface resonances. We demonstrate how these naturally arise within a single p-orbital manifold as a general consequence of a trigonal crystal field, and as such can be expected across a large number of compounds. Already, we demonstrate their existence in six separate TMDs, opening routes to tune, and ultimately exploit, their topological physics.

Full-gap superconductivity in spin-polarised surface states of topological semimetal β-PdBi2

A bulk superconductor possessing a topological surface state at the Fermi level is a promising system to realise long-sought topological superconductivity. Although several candidate materials have been proposed, experimental demonstrations concurrently exploring spin textures and superconductivity at the surface have remained elusive. Here we perform spectroscopic-imaging scanning tunnelling microscopy on the centrosymmetric superconductor β-PdBi2 that hosts a topological surface state. By combining first-principles electronic-structure calculations and quasiparticle interference experiments, we determine the spin textures at the surface, and show not only the topological surface state but also all other surface bands exhibit spin polarisations parallel to the surface. We find that the superconducting gap fully opens in all the spin-polarised surface states. This behaviour is consistent with a possible spin-triplet order parameter expected for such in-plane spin textures, but the observed superconducting gap amplitude is comparable to that of the bulk, suggesting that the spin-singlet component is predominant in β-PdBi2.Although several materials have been proposed as topological superconductors, spin textures and superconductivity at the surface remain elusive. Here, Iwaya et al. determine the spin textures at the surface of a superconductor β-PdBi2 and find the superconducting gap opening in all spin-polarised surface states.

Topologically protected surface states in a centrosymmetric superconductor β-PdBi2

The topological aspects of electrons in solids can emerge in real materials, as represented by topological insulators. In theory, they show a variety of new magneto-electric phenomena, and especially the ones hosting superconductivity are strongly desired as candidates for topological superconductors. While efforts have been made to develop possible topological superconductors by introducing carriers into topological insulators, those exhibiting indisputable superconductivity free from inhomogeneity are very few. Here we report on the observation of topologically protected surface states in a centrosymmetric layered superconductor, β-PdBi₂, by utilizing spin- and angle-resolved photoemission spectroscopy. Besides the bulk bands, several surface bands are clearly observed with symmetrically allowed in-plane spin polarizations, some of which crossing the Fermi level. These surface states are precisely evaluated to be topological, based on the Z₂ invariant analysis in analogy to three-dimensional strong topological insulators. β-PdBi₂ may offer a solid stage to investigate the topological aspect in the superconducting condensate.

Materials possessing topologically non-trivial electronic surface states are predicted to host exotic Majorana fermion excitations in the superconducting state. Here, the authors demonstrate the existence of topologically-protected surface states in the centrosymmetric layered superconductor β-PdBi2.

An in vitro study of long-term potentiation in the carp (Cyprinus carpio L.) olfactory bulb

Long-term potentiation (LTP) of synaptic transmission is considered a cellular mechanism for neural plasticity and memory formation. Previously, we showed that in the carp olfactory bulb, LTP occurs at the dendrodendritic mitral-to-granule cell synapse following tetanic electrical stimulation applied to the olfactory tract, and suggested that it is involved in the process of olfactory memory formation. As a first step towards understanding mechanisms underlying plasticity at this synapse, we examined the effects of various drugs (glutamate and GABA receptor agonists and antagonists, noradrenaline, and drugs affecting cAMP signaling) on dendrodendritic mitral-to-granule cell synaptic transmission in an in vitro preparation. Two forms of LTP are involved: a postsynaptic form (tetanus-evoked LTP) and a presynaptic form. The postsynaptic form is evoked at the granule cell dendrite following tetanic olfactory tract stimulation and is suppressed by the NMDA receptor antagonist, D-AP5, enhanced by noradrenaline, and occluded by the metabotropic glutamate receptor agonist, trans-ACPD. The presynaptic form occurs at the mitral cell dendrite following blockade of the GABA(A) receptor by picrotoxin and bicuculline, or via activation of cAMP signaling by forskolin and 8-Br-cAMP.

Pyruvate decarboxylase encoded by the PDC1 gene contributes, at least partially, to the decarboxylation of alpha-ketoisocaproate for isoamyl alcohol formation in Saccharomyces cerevisiae

Isoamyl alcohol is an important flavor component of yeast-fermented alcoholic beverages. To identify the enzyme and gene involved in the decarboxylation of alpha-ketoisocaproate (alpha-KIC) for isoamyl alcohol formation, the enzyme was partially purified and analyzed by mass spectrometry. The pyruvate decarboxylase encoded by the PDC1 gene was considered a likely candidate enzyme. Genetic analysis showed that the activity of alpha-KIC decarboxylase and production of isoamyl alcohol partially decreased in a pdc1 null mutant and increased in a transformant with a multi-copy plasmid carrying the PDC1 gene. These results indicate that pyruvate decarboxylase encoded by the PDC1 gene contributes, at least partially, to the decarboxylation of alpha-KIC for isoamyl alcohol formation.

Mass mating method in combination with G418- and aureobasidin A-resistance markers for efficient selection of hybrids from homothallic strains in Saccharomyces cerevisiae

We have developed a mass mating method using the spore suspensions of homothallic yeasts of Saccharomyces cerevisiae in combination with dominant selective drug resistance markers, Tn601(903) against geneticin and AUR1-C against aureobasidin A for the selection of the hybrids. To examine the effectiveness of these markers in the mass mating method, each marker was introduced into a homothallic wine yeast. Using a mixed culture of spore suspensions from the resultant transformants, many hybrids were screened by the drug resistance markers. This method is more practical than the spore-to-spore mating method because it does not require the use of a micromanipulator and many hybrids are obtained at one time. The resultant hybrids could be utilized for industrial brewing because plasmids, which are used to confer resistance markers, are easily eliminated from the hybrids by cultivation in a medium without drugs. We propose that the mass mating method using spore suspensions in combination with dominant selective geneticin- and aureobasidin A-resistance markers is useful for the selection of hybrids from industrial homothallic yeasts.

Histone variant macroH2A1.2 is mono-ubiquitinated at its histone domain

Histone macroH2A1.2 (macroH2A) is an unusual histone H2A variant with a large non-histone macrodomain at its carboxyl terminal. MacroH2A1.2 is enriched in facultative heterochromatin, including inactivated X chromosomes in mammalian females and senescence-associated heterochromatin foci. We show here that a small population of macroH2A1.2 is mono-ubiquitinated in human HeLa cells. Mass spectrometry analysis revealed that the specific targeting sites for the mono-ubiquitination are Lys115 and Lys116 of the histone domain. A corresponding Lys119 conserved in histone H2A is also mono-ubiquitinated by Ring protein in the polycomb group complex. We suggest that the mono-ubiquitination of macroH2A1.2 and histone H2A has similar or synergistic implications, but that the multiple ubiquitination sites in macroH2A1.2 might confer a variety of functions upon macroH2A1.2 to modulate chromatin states.

Percutaneous and laparoscopic approaches of radiofrequency ablation treatment for liver cancer

BACKGROUND/PURPOSE

Radiofrequency ablation (RFA) and microwave coagulation therapy (MCT) have been gaining acceptance as a standard method in the management strategy of liver cancer, for reasons of minimally invasive techniques and effective results. We present our experience of RFA and MCT in patients with liver cancer, and analyze retrospectively the advantages and disadvantages of both of the percutaneous and laparoscopic approaches.

METHODS

Thirty-two consecutive patients (23 men and 9 women) with 19 hepatocellular carcinomas (HCC), 12 metastatic liver cancers, and recurrent cholangiocellular carcinoma (CCC), were enrolled in this study. Out of these 32 patients, as a prior laparotomy, 19 underwent hepatectomy, colectomy, gastrectomy or cholecystectomy, and 15 were treated with the laparoscopic approach, 17 treated with the percutaneous approach, and 2 treated with the combined approach of those two. All of these procedures were carried out under general anesthesia with ultrasound guidance. Seven and 30 days after these procedures, an assessment helical computed tomography was done.

RESULTS

No sign of the residual tissues was noted in all patients except only one case.

CONCLUSIONS

The percutaneous approach was thought to be a more practical and less invasive method regardless previous laparotomy. For the laparoscopic approach, tumors located at the hepatic surface or margin were preferable candidates.

Oxidized forms of peroxiredoxins and DJ-1 on two-dimensional gels increased in response to sublethal levels of paraquat

We previously found hydroperoxide-responsive proteins (HPRPs), which are comprised of peroxiredoxin I (Prx I), Prx II, Prx III, Prx VI, HSP27, G3PDH and two unidentified proteins (HPRP-2' and HPRP-5'), in human umbilical vein endothelial cells. It was demonstrated by two-dimensional polyacrylamide gel electrophoresis (2D PAGE) that most HPRPs are converted into variants with lower pI upon exposure to hydroperoxides. In this study, we examined the HPRP response on 2D gels upon exposure of human endothelial cells (ECV304) to paraquat (PQ2+), which generates reactive oxygen species (ROS) within cells. PQ2+ exerted cytotoxic effects in a dose-(10 microM-10 mM) and time-(24-168 h) dependent manner. Two-dimensional PAGE analysis revealed that HPRP-2', and oxidized forms of Prx I, Prx II and Prx III were clearly increased upon exposure of cells to sublethal levels of PQ2+. Microsequence analysis revealed that both HPRP-2 and -2' were identical with human DJ-1. Moreover immunoblot analysis confirmed the increase of oxidized forms of Prx II, Prx III and DJ-1 in response to sublethal levels of PQ2+. PQ2+ treatment failed to increase fluorescence intensity derived from DCF, which is believed to be an indicator for intracellular levels of hydroperoxide. Although pentachlorophenol (PCP), an uncoupler of the mitochondrial respiratory chain, clearly elevated the fluorescence, PCP had no effect on HPRP response. These observations indicated that DCF-derived fluorescence is not correlated with HPRP response. We consider that the response of Prxs and DJ-1 on 2D gels could reflect endogenous production of ROS in PQ(2+)-treated cells, and might be a sensitive indicator of oxidative stress status.

Variants of peroxiredoxins expression in response to hydroperoxide stress

We examined patterns of the proteins that were expressed in human umbilical vein endothelial cells (HUVEC) in response to oxidative stress by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). When HUVEC were exposed to H2O2 at 100 microM for 60 min, the intensities of eight spots increased and those of eight spots decreased on 2D gels, as compared with control gels, after staining with silver. These changes were also observed after exposure of cells to hydroperoxides such as cumene hydroperoxide and tert-butyl hydroperoxide, but not after exposure to other reagents that induce oxidative stress such as S-alkylating compounds, nitric oxide, and salts of heavy metals. Therefore, these proteins were designated hydroperoxide responsive proteins (HPRPs). Microsequencing analysis revealed that these HPRPs corresponded to at least six pairs of proteins. Of these, four pairs of HPRPs were thioredoxin peroxidase I (TPx I), TPx II, TPx III, and the product of human ORF06, all of which belong to the peroxiredoxin (Prx) family and all of which are involved in the elimination of hydroperoxides. The other two pairs corresponded to heat shock protein 27 (HSP27) and glyceraldehyde-3-phosphate dehydrogenase (G3PDH), respectively. The variants that appeared in response to hydroperoxides had molecular masses similar to the respective native forms, but their pI values were lower by 0.2-0.3 pH units than those of the corresponding native proteins. These variants were detected on 2D gels after cells had been exposed to hydroperoxides in the presence of an inhibitor of protein synthesis. All variants were generated within 30 min of exposure to 100 microM H2O2. The variants of TPx I and TPx II appeared within 2 min of the addition of H2O2 to the culture medium. The HPRPs returned to their respective native forms after the removal of stress. Our results indicated that at least six proteins were structurally modified in response to hydroperoxides. Analysis by 2D-PAGE of 32P-labeled proteins revealed that the variant of HSP27 was its phosphorylated form while the other HPRPs were not modified by phosphorylation. Taken together, the results suggest that 2D-PAGE can reveal initial responses to hydroperoxide stress at the level of protein modification. Moreover, it is possible that the variants of four types of Prx might reflect intermediate states in the process of hydroperoxide elimination.

An ADP-ribosylation factor GTPase-activating protein Git2-short/KIAA0148 is involved in subcellular localization of paxillin and actin cytoskeletal organization

Paxillin acts as an adaptor protein in integrin signaling. We have shown that paxillin exists in a relatively large cytoplasmic pool, including perinuclear areas, in addition to focal complexes formed at the cell periphery and focal adhesions formed underneath the cell. Several ADP-ribosylation factor (ARF) GTPase-activating proteins (GAPs; ARFGAPs) have been shown to associate with paxillin. We report here that Git2-short/KIAA0148 exhibits properties of a paxillin-associated ARFGAP and appears to be colocalized with paxillin, primarily at perinuclear areas. A fraction of Git2-short was also localized to actin-rich structures at the cell periphery. Unlike paxillin, however, Git2-short did not accumulate at focal adhesions underneath the cell. Git2-short is a short isoform of Git2, which is highly homologous to p95PKL, another paxillin-binding protein, and showed a weaker binding affinity toward paxillin than that of Git2. The ARFGAP activities of Git2 and Git2-short have been previously demonstrated in vitro, and we provided evidence that at least one ARF isoform, ARF1, is an intracellular substrate for the GAP activity of Git2-short. We also showed that Git2-short could antagonize several known ARF1-mediated phenotypes: overexpression of Git2-short, but not its GAP-inactive mutant, caused the redistribution of Golgi protein beta-COP and reduced the amounts of paxillin-containing focal adhesions and actin stress fibers. Perinuclear localization of paxillin, which was sensitive to ARF inactivation, was also affected by Git2-short overexpression. On the other hand, paxillin localization to focal complexes at the cell periphery was unaffected or even augmented by Git2-short overexpression. Therefore, an ARFGAP protein weakly interacting with paxillin, Git2-short, exhibits pleiotropic functions involving the regulation of Golgi organization, actin cytoskeletal organization, and subcellular localization of paxillin, all of which need to be coordinately regulated during integrin-mediated cell adhesion and intracellular signaling.

Nitric oxide inactivates glyoxalase I in cooperation with glutathione

We previously found that glyoxalase I (Glo I) is inactivated upon exposure of human endothelial cells to extracellular nitric oxide (NO), and this event correlates with an increase in its pI on two-dimensional gels. In this study, we demonstrate that NO can modulate Glo I activity in cooperation with cellular glutathione (GSH). Severe depletion of intracellular GSH prevents the inactivation of Glo I in response to NO, although such depletion enhances the inactivation of glyceraldehyde-3-phosphate dehydrogenase (G3PDH), a well-known enzyme susceptible to NO-induced oxidation. S-Nitrosoglutathione (GSNO), an adduct of GSH and NO, lowers the activity of purified human Glo I, while S-nitrosocysteine (CysNO) inactivates the enzyme only in the presence of GSH. This indicates that a dysfunction in Glo I would require the formation of GSNO in situ. Competitive inhibitors of Glo I, S-(4-bromobenzyl)glutathione and its membrane-permeating form, completely abolish the NO action in vitro and inside cells, respectively. Taken together, these results reveal that Glo I can interact directly with GSNO, and that the interaction converts Glo I into an inactive form. Moreover, the data suggest that the substrate recognition site of Glo I might be involved in the interaction with GSNO.

A novel activation mechanism of caspase-activated DNase from Drosophila melanogaster

Caspase-activated DNase (CAD) is an enzyme that cleaves chromosomal DNA in apoptotic cells. Here, we identified a DNase in Drosophila Schneider cells that can be activated by caspase 3, and purified it as a complex of two subunits (p32 and p20). Using primers based on the amino acid sequence of the purified proteins, a cDNA coding for Drosophila CAD (dCAD) was cloned. The polypeptide encoded by the cDNA contained 450 amino acids with a calculated M(r) of 52,057, and showed significant homology with human and mouse CAD (22% identity). Mammalian CADs carry a nuclear localization signal at the C terminus. In contrast, dCAD lacked the corresponding sequence, and the purified dCAD did not cause DNA fragmentation in nuclei in a cell-free system. When dCAD was co-expressed in COS cells with Drosophila inhibitor of CAD (dICAD), a 52-kDa dCAD was produced as a heterotetrameric complex with dICAD. When the complex was treated with human caspase 3 or Drosophila caspase (drICE), the dICAD was cleaved, and released from dCAD. In addition, dCAD was also cleaved by these caspases, and behaved as a (p32)(2)(p20)(2) complex in gel filtration. When a Drosophila neuronal cell line was induced to apoptosis by treatment with a kinase inhibitor, both dCAD and dICAD were cleaved. These results indicated that unlike mammalian CAD, Drosophila CAD must be cleaved by caspases to be activated.

Superficial undifferentiated small cell carcinoma of the esophagus showing an interesting growing pattern in histology

We report a case of superficial undifferentiated small cell carcinoma of the esophagus. The histology of the tumor was interesting; there was squamous cell differentiation within the epithelial layer and undifferentiated small cells growing within the submucosal layer. The tumor had a negative Grimelius reaction, suggesting no differentiation into a hormone-producing carcinoma known as an apudoma (Amine Precursor Uptake and Decarboxylation (APUD)). The serum levels of ACTH and calcitonin were within normal limits. As the patient was elderly and had a history of pleural tuberculosis causing poor pulmonary function, and owing to the fulminant nature of this carcinoma, he underwent blunt dissection of the esophagus by posterior mediastinal gastric pull-up. The patient recovered quickly and was able to be discharged with a good quality of life until the tumor recurred as a liver metastasis 6 months later.

Cloning of chlorophyllase, the key enzyme in chlorophyll degradation: finding of a lipase motif and the induction by methyl jasmonate

Chlorophyllase (Chlase) is the first enzyme involved in chlorophyll (Chl) degradation and catalyzes the hydrolysis of ester bond to yield chlorophyllide and phytol. In the present study, we isolated the Chlase cDNA. We synthesized degenerate oligo DNA probes based on the internal amino acid sequences of purified Chlase from Chenopodium album, screened the C. album cDNA library, and cloned a cDNA (CaCLH, C. album chlorophyll-chlorophyllido hydrolase). The deduced amino acid sequence (347 aa residues) had a lipase motif overlapping with an ATP/GTP-binding motif (P-loop). CaCLH possibly was localized in the extraplastidic part of the cell, because a putative signal sequence for endoplasmic reticulum is at the N terminus. The amino acid sequence shared 37% identity with a function-unknown gene whose mRNA is inducible by coronatine and methyl jasmonate (MeJA) in Arabidopsis thaliana (AtCLH1). We expressed the gene products of AtCLH1 and of CaCLH in Escherichia coli, and they similarly exhibited Chlase activity. Moreover, we isolated another full-length cDNA based on an Arabidopsis genomic fragment and expressed it in E. coli, demonstrating the presence of the second Arabidopsis CLH gene (AtCLH2). No typical feature of signal sequence was identified in AtCLH1, whereas AtCLH2 had a typical signal sequence for chloroplast. AtCLH1 mRNA was induced rapidly by a treatment of MeJA, which is known to promote senescence and Chl degradation in plants, and a high mRNA level was maintained up to 9 h. AtCLH2, however, did not respond to MeJA.

Glyoxalase I is a novel nitric-oxide-responsive protein

To clarify the molecular mechanisms of nitric oxide (NO) signalling, we examined the NO-responsive proteins in cultured human endothelial cells by two-dimensional (2D) PAGE. Levels of two proteins [NO-responsive proteins (NORPs)] with different pI values responded to NO donors. One NORP (pI 5.2) appeared in response to NO, whereas another (pI 5.0) disappeared. These proteins were identified as a native form and a modified form of human glyoxalase I (Glox I; EC 4. 4.1.5) by peptide mapping, microsequencing and correlation between the activity and the isoelectric shift. Glox I lost activity in response to NO, and all NO donors tested inhibited its activity in a dose-dependent manner. Activity and normal electrophoretic mobility were restored by dithiothreitol and by the removal of sources of NO from the culture medium. Glox I was selectively inactivated by NO; compounds that induce oxidative stress (H(2)O(2), paraquat and arsenite) failed to inhibit this enzyme. Our results suggest that NO oxidatively modifies Glox I and reversibly inhibits the enzyme's activity. The inactivation of Glox I by NO was more effective than that of glyceraldehyde-3-phosphate dehydrogenase (G3PDH), another NO-sensitive enzyme. Thus Glox I seems to be a novel NO-responsive protein that is more sensitive to NO than G3PDH.

Galectin-1 regulates initial axonal growth in peripheral nerves after axotomy

The signals that prompt the axons to send out processes in peripheral nerves after axotomy are not well understood. Here, we report that galectin-1 can play an important role in this initial stage. We developed an in vitro nerve regeneration model that allows us to monitor the initial axon and support cell outgrowth from the proximal nerve stump, which is comparable to the initial stages of nerve repair. We isolated a factor secreted from COS1 cells that enhanced axonal regeneration, and we identified the factor as galectin-1. Recombinant human galectin-1 (rhGAL-1) showed the same activity at low concentrations (50 pg/ml) that are two orders of magnitude lower than those of lectin activity. A similarly low concentration was also effective in in vivo experiments of axonal regeneration with migrating reactive Schwann cells to a grafted silicone tube after transection of adult rat peripheral nerve. Moreover, the application of functional anti-rhGAL-1 antibody strongly inhibited the regeneration in vivo as well as in vitro. The same effect of rhGAL-1 was confirmed in crush/freeze experiments of the adult mouse sciatic nerve. Because galectin-1 is expressed in the regenerating sciatic nerves as well as in both sensory neurons and motor neurons, we suggest that galectin-1 may regulate initial repair after axotomy. This high activity of the factor applied under nonreducing conditions suggests that galectin-1 may work as a cytokine, not as a lectin.

[Differential diagnosis of ulcerative colitis]

Important points during differential diagnosis of ulcerative colitis from other inflammatory disorders are endoscopic examination and microbial studies of stools. In acute phase of enterocolitis in which waterly diarrhea with bloody stool and abdominal pain appeared, infectious enterocolitis by Shigella, Salmonella, Campylobacter and Yersinia, which sometimes causes mucosal edema, hyperemia, erosions and ulceration should be distinguished carefully. Microbial studies of stool would bring helpful information in such situation. In chronic phase of inflammatory diseases of bowel, they often showed chronic diarrhea associated with mucobloody stools and abdominal pain. They often revealed mucosal inflammation mimicking ulcerative colitis during endoscopic evaluation. Among them, most important diseases are amebic colitis, ischemic colitis, radiation colitis and antibiotics associated hemorrhagic colitis.

[Glucocorticoid treatment of ulcerative colitis]

Glucocorticoid is an important drug for ulcerative colitis. In this paper, the action mechanism of glucocorticoid, particularly that at molecular level in the cell, was mentioned. Mechanism in anti-inflammatory action, influence on cytokine production, immunosuppressive action and glucocorticoid resistance were reviewed.

[Appendiceal lesion in ulcerative colitis]

Recently, there has been a resurgence in the interest of the role of the appendix in ulcerative colitis. The lesion of appendix in ulcerative colitis is reviewed. Surgical studies were mainly reported in western countries and endoscopic studies were mainly reported in Japan. Epidemiological and experimental studies suggest a central role of the appendix in development of ulcerative colitis. It was considered that understanding of the significance of a skip lesion in the appendix would contribute to the elucidation of the pathogenesis of ulcerative colitis.

Epsin binds to the EH domain of POB1 and regulates receptor-mediated endocytosis

POB1 has been identified as a RalBP1-binding protein and has the Eps15 homology (EH) domain. The EH domain-containing proteins have been suggested to be involved in clathrin-dependent endocytosis. To clarify the function of POB1, we purified a protein which binds to the EH domain of POB1 from bovine brain cytosol and identified it as Epsin, which is known to bind to the EH domain of Eps15. Epsin has three Asn-Pro-Phe (NPF) motifs in the C-terminal region, which are known to form the core sequence for the binding to the EH domain. The EH domain of POB1 interacted directly with the region containing the NPF motifs of Epsin. Expression of Epsin in CHO-IR cells inhibited internalization of insulin although it affected neither insulin-binding nor autophosphorylation activities of the insulin receptor. Taken together with the observations that Epsin is involved in internalization of the receptors for epidermal growth factor and transferrin, these results suggest that Epsin is a binding partner of POB1 and their binding regulates receptor-mediated endocytosis.

Identification of the SH2 domain binding protein of Bruton's tyrosine kinase as BLNK--functional significance of Btk-SH2 domain in B-cell antigen receptor-coupled calcium signaling

Bruton's tyrosine kinase (Btk) is a critical component in the B-cell antigen receptor (BCR)-coupled signaling pathway. Its deficiency in B cells leads to loss or marked reduction in the BCR-induced calcium signaling. It is known that this BCR-induced calcium signaling depends on the activation of phospholipase Cgamma (PLCgamma), which is mediated by Btk and another tyrosine kinase Syk and that the SH2 and pleckstrin homology (PH) domains of Btk play important roles in this activation process. Although the importance of the PH domain of Btk has been explained by its role in the membrane targeting of Btk, the functional significance of the SH2 domain in the calcium signaling has remained merely a matter of speculation. In this report, we identify that one of the major Btk-SH2 domain-binding proteins in B cells is BLNK (B-cell linker protein) and present evidences that the interaction of BLNK and the SH2 domain of Btk contributes to the complete tyrosine phosphorylation of PLCgamma.

Identification of a novel phosphorylation site on histone H3 coupled with mitotic chromosome condensation

Histone H3 (H3) phosphorylation at Ser(10) occurs during mitosis in eukaryotes and was recently shown to play an important role in chromosome condensation in Tetrahymena. When producing monoclonal antibodies that recognize glial fibrillary acidic protein phosphorylation at Thr(7), we obtained some monoclonal antibodies that cross-reacted with early mitotic chromosomes. They reacted with 15-kDa phosphoprotein specifically in mitotic cell lysate. With microsequencing, this phosphoprotein was proved to be H3. Mutational analysis revealed that they recognized H3 Ser(28) phosphorylation. Then we produced a monoclonal antibody, HTA28, using a phosphopeptide corresponding to phosphorylated H3 Ser(28). This antibody specifically recognized the phosphorylation of H3 Ser(28) but not that of glial fibrillary acidic protein Thr(7). Immunocytochemical studies with HTA28 revealed that Ser(28) phosphorylation occurred in chromosomes predominantly during early mitosis and coincided with the initiation of mitotic chromosome condensation. Biochemical analyses using (32)P-labeled mitotic cells also confirmed that H3 is phosphorylated at Ser(28) during early mitosis. In addition, we found that H3 is phosphorylated at Ser(28) as well as Ser(10) when premature chromosome condensation was induced in tsBN2 cells. These observations suggest that H3 phosphorylation at Ser(28), together with Ser(10), is a conserved event and is likely to be involved in mitotic chromosome condensation.

Combined modality therapy for basaloid squamous carcinoma of the esophagus

A 61 year-old woman came to our hospital with dysphasia that had persisted for 2 months. Endoscopy and barium swallow showed a protruding tumor, about 6.0 cm long, in the midportion of the esophagus. A biopsy specimen showed squamous cell carcinoma of the esophagus. Computed tomography (CT) scan revealed adventitial involvement and lymph node metastases beneath the carina. After 2 courses of chemotherapy with cisplatin (CDDP) 100 mg for 1 day, 5-Fluorouracil (5-FU) 800 mg for 5 days, and leucovorin 30 mg for 5 days, complete regression of the tumor was observed by endoscopy and barium esophagography. Transthoracic esophagectomy with lymph node dissection was performed. Histologically, the muscle layers of the resected esophagus had been replaced by fibrous tissue; however, small foci of basaloid squamous carcinoma (BSC) were found in the submucosa. Six months after surgery, a CT scan revealed a metastatic lymph node around the right main bronchus. Chemotherapy and radiotherapy resulted in the disappearance of the metastasis. The patient has survived for more than 3 years since surgery with a good quality of life.

Cutting edge: combined treatment of TNF-alpha and IFN-gamma causes redistribution of junctional adhesion molecule in human endothelial cells

Proinflammatory cytokines such as TNF-alpha and IFN-gamma induce cell adhesion molecules in endothelial cells and promote transmigration of leukocytes across endothelial cells. However, when those two were administered together, leukocyte transmigration paradoxically decreased. We cloned a human and bovine homologue of the junctional adhesion molecule (JAM), a novel molecule at the tight junction, and examined the effects of proinflammatory cytokines on JAM in HUVECs. The combined treatment of TNF-alpha plus IFN-gamma caused a disappearance of JAM from intercellular junctions. However, flow cytometry, cell ELISA, and subcellular fractionation analysis demonstrated that the amount of JAM was not reduced. This suggested that JAM changed its distribution in response to proinflammatory cytokines. This redistribution of JAM might be involved in a decrease in transendothelial migration of leukocytes at inflammatory sites.

Small G protein Ral and its downstream molecules regulate endocytosis of EGF and insulin receptors

The involvement of Ral and its downstream molecules in receptor-mediated endocytosis was examined. Expression of either RalG23V or RalS28N, which are known to be constitutively active and dominantnegative forms, respectively, in A431 cells blocked internalization of epidermal growth factor (EGF). Stable expression of RalG23V or RalS28N in CHO-IR cells also inhibited internalization of insulin. Internalization of EGF and insulin was not affected by full-length RalBP1 which is an effector protein of Ral, but was inhibited by its C-terminal region which binds directly to Ral and POB1. POB1 is a binding protein of RalBP1 and has the Eps15 homology (EH) domain. Deletion mutants of POB1 inhibited internalization of EGF and insulin. However, internalization of transferrin was unaffected by Ral, RalBP1, POB1 and their mutants. Epsin and Eps15 have been reported to be involved in the regulation of endocytosis of the receptors for EGF and transferrin. The EH domain of POB1 bound directly to Epsin and Eps15. Taken together with the observation that EGF and insulin activate Ral, these results suggest that Ral, RalBP1 and POB1 transmit the signal from the receptors to Epsin and Eps15, thereby regulating ligand-dependent receptor-mediated endocytosis.

Isolation and characterization of the glyceraldehyde-3-phosphate dehydrogenase gene of Lentinus edodes

The glyceraldehyde-3-phosphate dehydrogenase (GPD) gene of Lentinus edodes was isolated from a genomic DNA library and cDNA corresponding to this gene was isolated from a mycelium cDNA library. The L. edodes GPD gene was found to encode a 337-aa protein. By comparison of the cDNA and genomic DNA sequences, the presence of eight introns in the GPD gene was confirmed. The putative amino acid sequence of the L. edodes GPD gene product showed high similarity to those of other basidiomycetes. The results of Southern blot analyses suggested that only one copy of the GPD gene is present in the genome of L. edodes. The promoter region was found to contain a CT-rich stretch, two CAAT boxes and a consensus TATA box. In addition, the transcript of the GPD gene was found to be expressed constitutively and strongly. These results suggest that the promoter of the L. edodes GPD gene may be very useful as a component of transformation vectors.