Superperiodic assembly of 2,6-diethynylpyridine through weak hydrogen bonds at the 1-phenyloctane/HOPG interface

Regardless of the absence of alkyl chains and conventional hydrogen bonding sites as well as its small size, 2,6-diethynylpyridine forms an ordered array at the interface between 1-phenyloctane and highly oriented pyrolytic graphite (HOPG) under room temperature conditions, as revealed by scanning tunneling microscopy. We propose a model for the superperiodic molecular arrangement with reference to the bulk crystal structure, in which the surface pattern is governed by weak C-H...N and C-H...pi hydrogen bonds as well as the periodic potential of the underlying graphite surface.

Fractalkine mediates T cell-dependent proliferation of synovial fibroblasts in rheumatoid arthritis

OBJECTIVE

In rheumatoid arthritis (RA), synovial fibroblasts proliferate excessively, eventually eroding bone and cartilage. The aim of this study was to examine the mechanisms through which CD4 T cells, the dominant lymphocyte population in patients with rheumatoid synovitis, regulate synoviocyte proliferation.

METHODS

Fibroblast-like synoviocyte (FLS) lines were established from rheumatoid synovium. CD4 T cells from patients with RA and age-matched control subjects were cultured on FLS monolayers. FLS proliferation was quantified by cytometry, using carboxyfluorescein succinimidyl ester staining or microscopic enumeration of PKH26-stained FLS. Surface expression of the fractalkine (FKN) receptor CX(3)CR1 was monitored by fluorescence-activated cell sorting. The induction of CX(3)CR1 and its ligand FKN in FLS was quantified by real-time polymerase chain reaction.

RESULTS

The proliferation of FLS was significantly increased in the presence of CD4 T cells from patients with RA compared with control T cells. CD4+,CD28- T cells were particularly effective in supporting FLS growth, inducing a 25-fold expansion compared with a 5-fold expansion induced by CD4+,CD28+ T cells. The growth-promoting activity of CD4+,CD28- T cells was mediated through CX(3)CR1, a chemokine receptor expressed on both T cells and FLS. Anti-CX(3)CR1 antibodies inhibited T cell production of tumor necrosis factor alpha (TNFalpha) and suppressed FLS proliferation. TNFalpha amplified the expansion of FLS by enhancing their expression of CX(3)CR1 and FKN.

CONCLUSION

FKN-CX(3)CR1 receptor-ligand interactions regulate FLS growth and FLS-dependent T cell function. FLS stimulate autocrine growth by releasing FKN and triggering the activity of their own CX(3)CR1. This growth-promotion loop is amplified by TNFalpha produced by CX(3)CR1-expressing T cells upon stimulation by FKN-expressing FLS. These data assign a critical role to FKN and its receptor in fibroblast proliferation and pannus formation in RA.

Ceramide and adenosine 5'-monophosphate-activated protein kinase are two novel regulators of 11beta-hydroxysteroid dehydrogenase type 1 expression and activity in cultured preadipocytes

Increased activity of intracellular glucocorticoid reactivating enzyme, 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) in obese adipose tissue contributes to adipose dysfunction. As recent studies have highlighted a potential role of preadipocytes in adipose dysfunction, we tested the hypothesis that a variety of metabolic stress mediated by ceramide or AMP-activated protein kinase (AMPK) would regulate 11beta-HSD1 in preadipocytes. The present study is the first to show that 1) expression of 11beta-HSD1 in 3T3-L1 preadipocytes was robustly induced when cells were treated with cell-permeable ceramide analogue C(2) ceramide, bacterial sphingomyelinase, and sphingosine 1-phosphate, 2) 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR)-induced activation of AMPK augmented the expression and enzyme activity of 11beta-HSD1, and 3) these results were reproduced in human preadipocytes. We demonstrate for the first time that C(2) ceramide and AICAR markedly induced the expression of CCAAT/enhancer-binding protein (C/EBP) beta and its binding to 11beta-HSD1 promoter. Transient knockdown of C/EBPbeta protein by small interfering RNA markedly attenuated the expression of 11beta-HSD1 induced by C(2) ceramide or AICAR. The present study provides novel evidence that ceramide- and AMPK-mediated signaling pathways augment the expression and activity of 11beta-HSD1 in preadipocytes by way of C/EBPbeta, thereby highlighting a novel, metabolic stress-related regulation of 11beta-HSD1 in a cell-specific manner.

A new technique for intestinal isoperistaltic anastomosis utilizing a linear stapler for enlargement after anastomosis performed with a circular stapler

BACKGROUND

The high incidence of anastomotic stenosis after gastrointestinal surgery using circular staplers is a major problem. In response, we have developed a new technique that uses a linear stapler to enlarge an anastomotic opening made using a circular stapler.

METHODS

Anastomoses were created by the new technique or by the conventional approach using a circular stapler in pig small intestine. The method was also applied in treatment of a colon cancer patient.

RESULTS

The area of the anastomotic opening obtained with the new technique was more than 3 times that in the control (p < 0.001), with no significant difference between the methods in a leak test. Follow-up of the patient undergoing surgery with this approach revealed an uneventful course with a widely patent anastomosis confirmed after 3 months.

CONCLUSIONS

This procedure provides a larger anastomotic opening than conventional anastomosis with circular staplers, without impairing the integrity of the anastomosis.

Costimulatory pathways in rheumatoid synovitis and T-cell senescence

The pathogenesis of rheumatoid arthritis (RA) is determined by a complex interaction of genetic and environmental factors. Of all risk factors, age has the largest impact. RA occurs most often during the postmenopausal period of life, with incidence rates peaking in the eighth decade. While age is generally accepted as an etiologic factor for failure of immunocompetence, much less is understood about the role of T-cell senescence in autoimmunity. We have hypothesized that senescent T cells are particularly prone to be activated in specialized microenvironments, such as the synovial membrane. CD4 T cells in the senescence program were identified by the loss of CD28. Gene expression profiling documented that CD28- T cells have acquired a spectrum of regulatory receptors that are usually seen only on NK cells. Such regulatory receptors include stimulatory and inhibitory members of the killer immunoglobulin-like receptor (KIR) family, the stimulatory c-type lectin receptor NKG2D, and CX3CR1, the receptor for the chemokine fractalkine. Synovial fibroblasts express the relevant ligands, thus providing stimulatory signals to tissue-infiltrating T cells. The signaling pathways of these regulatory receptors are complex and dependent on the individual T cells, some of which express important adapter molecules such as DAP10 and DAP12. Inhibitory KIRs on T cells are often only partially functional. Our data suggest that, by virtue of altered receptor profiles, conventional tolerance mechanisms can be evaded in the aging host. By acquiring a new set of regulatory receptors, senescent CD4 T cells become responsive to novel environmental cues and find ideal stimulatory conditions in the synovial microenvironment.

Integrin-linked kinase activity is associated with interleukin-1α-induced progressive behavior of pancreatic cancer and poor patient survival

Cancer cell adhesion and invasion into extracellular matrix are regulated by integrin-linked kinase (ILK) activity in a phosphatidylinositol 3-kinase (PI3-K)-dependent manner. In this study, we demonstrated that ILK and beta(1)-integrin play important roles in interleukin (IL)-1alpha-induced enhancement of adhesion and invasion of pancreatic cancer cells through p38 mitogen-activated protein kinase (MAPK) signaling pathway and activator protein-1 (AP-1) activation. Alteration of ILK kinase activity controlled IL-1alpha-induced p38 MAPK phosphorylation and its downstream AP-1 activation with subsequent regulation of pancreatic cancer cell adhesion and invasion. Overexpressed ILK enhances the IL-1alpha-induced p38 MAPK phosphorylation more strongly through glycogen synthase kinase 3 (GSK-3) activation, and subsequently induces AP-1 activation, which promotes aggressive capabilities of pancreatic cancer cells. In contrast, knockdown of ILK kinase activity inhibits the IL-1alpha-induced activation of MAPK/AP-1 pathway via inhibition of GSK-3 phosphorylation. In immunohistochemical analysis, statistically significant association between strong expression of ILK and poor prognosis of pancreatic cancer patients were observed, and strong expression of ILK in cancerous tissues can be a significant prognostic indicator of pancreatic cancer patients. Our results suggest that ILK is involved with aggressive capability in pancreatic cancer and that these regulations can be helpful to understand biological processes for a better translational treatment for pancreatic cancer patients.

Effect of the terminal amino group of a linker arm and its length at the C5 position of a pyrimidine nucleoside on the thermal stability of DNA duplexes

2'-Deoxyuridine derivatives bearing a substituent at the C5-position, which has a different chain length and a different functional group (methyl or amino), were synthesized and incorporated into oligodeoxyribonucleotides. The effect of the substituent groups in the major groove on the stability of the duplexes was investigated by UV melting experiments. It was found that the stabilization of these duplexes by a terminal amino group depended on the length of a linker arm.

Cell-based immunotherapy with suppressor CD8+ T cells in rheumatoid arthritis

The chronic persistence of rheumatoid synovitis, an inflammation driven by activated T cells, macrophages, and fibroblasts causing irreversible joint damage, suggests a failure in physiologic mechanisms that down-regulate and terminate chronic immune responses. In vitro CD8(+)CD28(-)CD56(+) T cells tolerize APCs, prevent the priming of naive CD4(+) T cells, and suppress memory CD4(+) T cell responses. Therefore, we generated CD8(+)CD28(-)CD56(+) T cell clones from synovial tissues, expanded them in vitro, and adoptively transferred them into NOD-SCID mice engrafted with synovial tissues from patients with rheumatoid arthritis. Adoptively transferred CD8(+)CD28(-)CD56(+) T cells displayed strong anti-inflammatory activity. They inhibited production of IFN-gamma, TNF-alpha, and chemokines in autologous and HLA class I-matched heterologous synovitis. Down-regulation of costimulatory ligands CD80 and CD86 on synovial fibroblasts was identified as one mechanism of immunosuppression. We propose that rheumatoid synovitis can be suppressed by cell-based immunotherapy with immunoregulatory CD8(+) T cells.

T cell costimulation by fractalkine-expressing synoviocytes in rheumatoid arthritis

OBJECTIVE

Patients with rheumatoid arthritis (RA) accumulate prematurely aged T cells that have acquired a new profile of regulatory receptors. Many of the de novo-expressed receptors are typically found on natural killer cells, including CX(3)CR1, the receptor for the chemokine fractalkine (FKN). This study explored whether interactions between CX(3)CR1 and FKN are relevant for T cell functions in rheumatoid synovitis.

METHODS

FKN expression was examined by real-time polymerase chain reaction and immunohistochemistry. CX(3)CR1 expression on peripheral blood T cells was analyzed by flow cytometry. T cell activation was quantified by determining proliferative responses, interferon-gamma (IFNgamma) secretion, and granule release. Fibroblast-like synoviocyte (FLS)/T cell adhesion was measured by the retention of 5-carboxyfluorescein diacetate succinimidyl ester-labeled T cells on FLS monolayers.

RESULTS

FKN was expressed on cultured synovial fibroblasts and hyperplastic synoviocytes in the rheumatoid tissue. Among CD4+ T cells, only senescent CD28- T cells were positive for CX(3)CR1 (P < 0.001). Such CD4+,CD28-,CX(3)CR1+ T cells strongly adhered to FLS, with soluble FKN blocking the interaction. FKN expressed on FLS costimulated T cell-activating signals and amplified proliferation, IFNgamma production, and expulsion of cytoplasmic granules.

CONCLUSION

Senescent CD4+ T cells that accumulate in rheumatoid arthritis aberrantly express CX(3)CR1. FKN, which is membrane-anchored on synoviocytes, enhances CD4+ T cell adhesion, provides survival signals, and costimulates the production of proinflammatory cytokines as well as the release of granules. By virtue of their altered receptor profile, senescent CD4+ T cells receive strong stimulatory signals from nonprofessional antigen-presenting cells in the synovial microenvironment.

Immunohistochemical analysis of molecular biological factors in intraductal papillary-mucinous tumors and mucinous cystic tumors of the pancreas

BACKGROUND

To investigate the malignancy and differentiation of intraductal papillary-mucinous tumors (IPMTs) and mucinous cystic tumors (MCTs) of the pancreas, clinicopathologic characteristics and immunohistochemical features were analyzed.

METHODS

The clinicopathologic characteristics and immunohistochemical features of 24 patients with IPMT and 8 with MCT who underwent pancreatic resections at our hospital were examined. Immunohistochemical features analyzed included expression of p53 protein, proliferating cell nuclear antigen, integrins, interleukin-1 receptor type I, and hormone-associated receptors, and the factors correlated with malignancy were identified by multiple logistic regression.

RESULTS

Among the IPMTs, there were 16 intraductal papillary adenomas, 5 intraductal papillary adenocarcinomas, and 3 moderate dysplasias. Among the MCTs, there were 6 mucinous cyst adenomas and 2 mucinous cyst adenocarcinomas. Multivariate analysis revealed that of the clinicopathologic characteristics, only the presence of mural nodules (odds ratio (OR) 7.12, P = 0.044) was independently correlated with the malignancy of IPMTs, and that of the immunohistochemical features, only alpha integrin subunit expression was independently correlated with malignancy of pancreatic mucinous tumors (OR 15.6, P = 0.036), especially IPMTs (OR 35.7, P = 0.012).

CONCLUSION

These results indicate that alpha-containing integrin expression can be a significant marker of malignancy in pancreatic mucinous tumors.

Possible presence of O-linked carbohydrate in the human male reproductive tract CD52

Male reproductive tract CD52 (mrtCD52) is an antigen recognized by a complement-dependent sperm-immobilizing monoclonal antibody (SI-Abs) derived in an infertile patient. The molecule has been shown to contain a unique N-linked carbohydrate that does not cross-react with other tissues. In this study, we have investigated whether O-linked carbohydrate as well as N-linked carbohydrate is present in mrtCD52 using specific lectins and anti-CD52 core peptide antiserum. The lectin PNA, which recognizes O-linked carbohydrate [Galbeta1-3GalNAc], reacted with mrtCD52 and showed a similar polymorphic reaction pattern to that of the anti-peptide antiserum in western blotting analysis on two-dimensional SDS-PAGE. The PNA-reactive spots disappeared after removal of O-linked carbohydrate, but not after removal of N-linked carbohydrate. These results suggest that O-linked carbohydrate is present in mrtCD52. The moiety may possibly contribute to a specific antigenic epitope of mrtCD52.

Convenient synthesis of arabinonucleoside containing oligodeoxyribonucleotides

C2 substituted arabinofuranosyluracil derivatives were synthesized and its incorporations into DNA were easily carried out by using post-synthetic modification.

Synthesis and properties of a new type DNA dendrimer

We have designed a new type of a DNA dendrimer which has rigid branched structure. The branching molecule was prepared from 1,3,5-tribromobenzene. The dendrimer unit, in which three oligonucleotide-chains, two molecules of T15 and one molecule of A15, linked to the branching molecule, was synthesized by an automated DNA synthesizer. The properties of the dendrimer unit and dendrimer formation by inter-molecular association of T15 and A15 chains of the dendrimer unit will be presented.

Enzymatic synthesis of modified DNA by PCR

We synthesized various 5'-triphosphates of C5-substituted 2'-deoxyuridine derivatives bearing methylene linker at C5-alpha position. We examined whether the C5-substituted 2'-deoxyuridine 5'-triphosphates (dUTP) can work as a substrate for the modified DNA synthesis by PCR. We found that only KOD dash DNA polymerase, a thermostable DNA polymerase from extremely thermophilic archaeum, accepted the modified substrates in place of TTP for PCR forming the corresponding modified DNAs. On the other hand, no other DNA polymerase could accept these TTP analogues.

Epitope analysis for human sperm-immobilizing monoclonal antibodies, MAb H6-3C4, 1G12 and campath-1

Human monoclonal antibody, MAb H6-3C4, possesses strong sperm immobilizing activity. MAb H6-3C4 has been suggested by several research groups to react with a carbohydrate moiety of male reproductive tract CD52 (mrtCD52). In the present study, we analysed the epitope on mrtCD52 for MAb H6-3C4 and found that it was polymorphic in Western blot analysis and disappeared after enzymatic removal of the N-linked carbohydrate moiety. Two other monoclonal antibodies (1G12, campath-1) with sperm-immobilizing activity recognized mrtCD52 in a polymorphic manner similar to MAb H6-3C4. Further analysis showed that 1G12 recognized a structure formed by the peptide and/or a glycosylphosphatidylinositol (GPI) anchor portion as does campath-1. Results of a lectin binding assay suggested the presence of O-linked carbohydrates on mrtCD52. Our results also indicated that the peptide portion of CD52 could serve as an epitope for sperm-immobilizing antibodies. It was concluded that the epitope of MAb H6-3C4 is similar to, but distinct from, those of 1G12 and campath-1, and that mrtCD52 contains different antigenic epitopes.

Effects of whisky on plasma gastrin and cholecystokinin in young adult men

Whisky (1 g/kg, 21.5% alcohol) was administered orally to healthy young adult male volunteers, and changes in the plasma concentrations of alcohol, acetaldehyde, gastrin, cholecystokinin (CCK) and serum amylase were measured over time. Values for alcohol and acetaldehyde rapidly reached a peak at 30-45 min after alcohol intake, followed by a gradual decline. The plasma gastrin concentration showed a rapid elevation, while the plasma CCK concentration did not exhibit any significant changes in the early phase after alcohol intake. Elevation of CCK was observed after 75 min, however. These results show that intake of whisky stimulates the secretion of gastrin and is associated with a later increase in CCK.

Effect of galanin on plasma glucose, insulin and pancreatic glucagon in dogs

The effect of synthetic galanin on plasma glucose, insulin and pancreatic glucagon levels in dogs was studied. Infusion of galanin caused a rapid, reversible and dose-dependent reduction in basal insulin level. A maximal increase in blood glucose level accompanying the insulin decrease was observed when galanin was administered at a dose of 4 micrograms/kg per h. Pancreatic glucagon levels showed little change compared with basal secretion. These results indicate that galanin is involved in the regulation of glucose through control of insulin secretion.

Effect of Bcl-2 overexpression on establishment of ipsilateral retinocollicular projection in mice

During perinatal development in rodents, ipsilateral retinofugal projection spreading over the superior colliculus is eventually restricted to the rostromedial region. Since this restriction is accompanied by the apoptotic death of more than half of the retinal ganglion cells (RGCs), cell death is believed to play a major role in the restriction of transient ipsilateral projection from the retina to the superior colliculus. To determine the role of RGC death in the establishment of ipsilateral retinofugal projection, we examined the projection pattern in the superior colliculus and the dorsal lateral geniculate nucleus of transgenic mice overexpressing the human bcl-2 gene, which protects against cell death in the CNS. Retrograde labeling of RGCs showed that the number of ipsilaterally projecting RGCs in adult transgenic mice was approximately twice that in adult wild-type mice, indicating that the naturally occurring death of RGCs was prevented in these mutant mice. However, anterograde labeling of ipsilateral retinofugal pathways revealed that the innervation of retinogeniculate and retinocollicular projections was as restricted in transgenic mice as in wild-type mice. From these results we suggest that restriction of ipsilateral retinofugal projection during development is due to retraction or elimination of excessive terminals rather than to naturally occurring RGC death.

Alteration of integrins by interleukin-1alpha in human pancreatic cancer cells

INTRODUCTION

Adhesion of tumor cells to extracellular matrix (ECM) proteins plays an important role in tumor invasion and metastasis.

AIMS

To investigate the expression of integrins in human pancreatic cancer cell lines and its alteration by interleukin (IL)-1alpha to examine the mechanism of adhesion of metastatic human pancreatic cancer cells to ECM proteins.

METHODOLOGY

The expression of integrin subunits and their alteration by IL-1alpha were examined by flow-cytometric analysis and cellular enzyme-linked immunosorbent assay in three metastatic human pancreatic cancer cell lines (AsPC-1, BxPC-3, and SW1990) and two nonmetastatic cancer cell lines (PaCa-2 and PANC-1). In addition, assays of cancer cell adhesion to ECM proteins were performed to investigate if increased integrin expression actually affected the adhesive interaction between cancer cells and the putative integrin ECM ligands.

RESULTS

The alpha(6) subunit expressed in metastatic cancer cells was enhanced by IL-1alpha. Metastatic cancer cells also showed preferential adherence to laminin compared with nonmetastatic cancer cells, and this was enhanced by IL-1alpha.

CONCLUSION

In pancreatic cancer, the enhancement of alpha(6)beta(1) integrin by IL-1alpha through IL-1 receptor type I, as well as the expression of alpha(6)beta(1) integrin, plays an important role in metastasis formation.

A phycocyanin-deficient mutant of synechocystis PCC 6714 with a single-base substitution upstream of the cpc operon

The structure and expression of the cpc operon encoding phycocyanin subunits and linker polypeptides in a phycocyanin-deficient mutant (PD-1) and the wild-type of Synechocystis PCC 6714 were analyzed. The results of sequence and Northern blot analyses of the wild type indicate that the cpc operon consists of cpcB, cpcA, cpcC1, cpcC2 and cpcD, in that order. The levels of the transcripts in PD-1 were one-tenth to one-sixth as high as those in the wild type. In the PD-1 genome, a single-base substitution of C for T has occurred at base 259 upstream of the translational initiation codon of cpcB (at three bases downstream of the putative -10 region). To evaluate the in vivo transcription activities of these promoters in a cyanobacterium, we constructed vectors for the transformation of Synechococcus PCC7942, pANY1 and pANY2, which contain the upstream region of cpcB of the wild type (pANY1) or PD-1 (pANY2) and the promoter-less luxAB fusion. The bioluminescence of the transformants with pANY2 was one-tenth to one-sixth as high as that with pANY1. The coincidence of the results of Northern analysis and the promoter assay shows that the phycocyanin deficiency of PD-1 is due to the single-base substitution in the upstream region of the cpc operon.

Molecular analysis of familial androgen insensitivity syndrome due to replacement of glutamic acid 802 by lysine

We studied a Japanese family presenting at least two cases of complete androgen insensitivity syndrome (CAIS) and negative androgen receptor binding. The index subject showed a 46, XY karyotype and a complete female phenotype. For the purpose of further diagnosis and genetic counseling, molecular analysis of the androgen receptor (AR) gene was performed. Direct sequencing of the AR gene identified a mutation at nucleotide 2935 (A-->G). This replacement was a novel missense mutation, resulting in the substitution of glutamic acid 802 by lysine which deleted a recognition site for EcoRI in exon 6 of the AR gene. We identified another affected individual, using chromosome and molecular analysis of the AR gene at exon 6. Furthermore, although heterozygote carriers could not be identified on clinical grounds, molecular identification of healthy individuals and heterozygote carriers in the family members provided definitive information for genetic counseling. We believe that the molecular analysis of familial CAIS is very informative for both the affected individuals and other family members.

Topological specificity in reinnervation of the superior colliculus by regenerated retinal ganglion cell axons in adult hamsters

In normal rodents there is a precise topology of the retinocollicular projection, the nasotemporal and ventrodorsal axes of the retina being respectively projected onto the caudorostral and mediolateral axes of the contralateral superior colliculus (SC). We evaluated the distribution of regenerated retinal ganglion cell (RGC) axon terminals in the SC of adult hamsters in which an unbranched peripheral nerve graft was directed from the retina to the contralateral SC. Responses to visual stimulation of individual RGCs were recorded from terminal arbors of their regenerated axons in the reinnervated SC. Retinal positions of these RGCs were inferred from the locations of their visual receptive fields. At some sites in the reinnervated SC, axon terminal arbors converged from widely separated RGCs. Conversely, axon terminal arbors at widely separated sites in the SC could emanate from contiguous RGCs. To assess whether any tendency for order was superimposed on the apparent disorganization of the regenerated projection, we evaluated the relative positions of pairs of RGC terminals in the SC in relation to the relative retinal locations of the corresponding pairs of RGCs. Among the 983 pairs of RGCs able to be evaluated from nine animals studied 30-60 weeks after grafting, there was a statistically significant 3/2 tendency for the more nasally situated of two RGCs to project its terminal more caudally in the SC than that of the more temporally situated RGC. A similar tendency toward appropriate organization was not found with respect to the ventrodorsal axis of the retina and the mediolateral axis of the SC.

Synthesis and characterization of polyamine-based biomimetic catalysts as artificial ribonuclease

Several polyamine derivatives (I-V) conjugated with or without an intercalative moiety were prepared as ribonuclease mimics. Although no DNA-cleaving activity was observed for all compounds tested, mimics I, III, and V bearing an intercalative moiety along with the primary amine and/or imidazole moieties exhibited potent RNA-cleaving activity at near physiological pH. The RNA-cleaving reactions of the compounds show characteristic bell-shaped pH dependency, and the optimal pH values for III and V were well correlated to the pKa values of their active sites, primary amine, and imidazole moieties.

Identification of ISC1 (YER019w) as inositol phosphosphingolipid phospholipase C in Saccharomyces cerevisiae

Sphingolipids have emerged as novel bioactive mediators in eukaryotic cells including yeast. It has been proposed that sphingomyelin (SM) hydrolysis and the concomitant generation of ceramide are involved in various stress responses in mammalian cells. The yeast Saccharomyces cerevisiae has inositol phosphosphingolipids (IPS) instead of SM and glycolipids, and synthesis of IPS is indispensable to its growth. Although the genes responsible for the synthesis of IPS have been identified, the gene(s) for the degradation of IPS has not been reported. Here we show that ISC1 (YER019w), which has homology to bacterial neutral sphingomyelinase (SMase), encodes IPS phospholipase C (IPS-PLC). First, we observed that overexpression of ISC1 greatly increased neutral SMase activity, and this activity was dependent on the presence of phosphatidylserine. Cells deleted in ISC1 demonstrated negligible neutral SMase activity. Because yeast cells have IPS instead of SM, we investigated whether IPS are the physiologic substrates of this enzyme. Lysates of ISC1-overexpressing cells demonstrated very high PLC activities on IPS. Deletion of ISC1 eliminated endogenous IPS-PLC activities. Labeling yeast cells with [(3)H]dihydrosphingosine showed that IPS were increased in the deletion mutant cells. This study identifies the first enzyme involved in catabolism of complex sphingolipids in S. cerevisiae.

Nonenzymatic template-directed condensation of short-chained oligouridylates on a poly(A) template

An oligouridylate with chain-length of more than three was condensed on a polyadenylate [poly(A)] template with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDAC) in imidazole buffer. The condensation reaction proceeds via the phosphorimidazolide of the oligouridylate as an intermediate. Pentauridylate [(pU)5] was converted to decauridylate [(pU)10] in 10% yield at 0 degree C for 7 days in the presence of the poly(A) template, while no coupling product was obtained in the absence of the poly(A) template. The resulting linkage of the (pU)10 was mainly 2'-5' linkage.

Synthesis of oligodeoxyribonucleotides bearing a functional group at 2'-position by post-synthetic modification

A novel 2'-thio-2'-deoxyuridine derivative bearing a reactive ester at 2'-position was synthesized and incorporated into oligodeoxyribonucleotides (ODNs) for the post-synthetic modification of ODNs. This ODNs was reacted with several amines to give ODNs having a functional group at 2'-position.

Synthesis and properties of oligodeoxynucleotides containing a C-2 polyamine-bearing deoxyguanosine residue as artificial ribonuclease

Oligodeoxynucleotides containing a 2-fluoro-2'-deoxyinosine residue substituting normal 2'-deoxyguanosine residue were synthesized. Upon treating with ethanol solution of polyamine, the fluorine atom in the oligomers were readily substituted with the polyamine. The thermal stabilities of the duplexes consisted of the polyamine-bearing oligomers and their cDNAs as well as their RNA cleaving activity were investigated.

Interaction of UvrA and UvrB proteins with a fluorescent single-stranded DNA. Implication for slow conformational change upon interaction of UvrB with DNA

UvrA and UvrB proteins play key roles in the damage recognition step in the nucleotide excision repair. However, the molecular mechanism of damage recognition by these proteins is still not well understood. In this work we analyzed the interaction between single-stranded DNA (ssDNA) labeled with a fluorophore tetramethylrhodamine (TMR) and Thermus thermophilus HB8 UvrA (ttUvrA) and UvrB (ttUvrB) proteins. TMR-labeled ssDNA (TMR-ssDNA) as well as UV-irradiated ssDNA stimulated ATPase activity of ttUvrB more strongly than did normal ssDNA, indicating that this fluorescent ssDNA was recognized as damaged ssDNA. The addition of ttUvrA or ttUvrB enhanced the fluorescence intensity of TMR-ssDNA, and the intensity was much greater in the presence of ATP. Fluorescence titration indicated that ttUvrA has higher specificity for TMR-ssDNA than for normal ssDNA in the absence of ATP. The ttUvrB showed no specificity for TMR-ssDNA, but it took over 200 min for the fluorescence intensity of the ttUvrB-TMR-ssDNA complex to reach saturation in the presence of ATP. This time-dependent change could be separated into two phases. The first phase was rapid, whereas the second phase was slow and dependent on ATP hydrolysis. Time dependence of ATPase activity and fluorescence polarization suggested that changes other than the binding reaction occurred during the second phase. These results strongly suggest that ttUvrB binds ssDNA quickly and that a conformational change in ttUrvB-ssDNA complex occurs slowly. We also found that DNA containing a fluorophore as a lesion is useful for directly investigating the damage recognition by UvrA and UvrB.

Synthesis of oligodeoxyribonucleotide bearing 2'-S-alkyl residue and its effect on the duplex stability

2'-Deoxy-2'-S-hexyluridine derivative was synthesized from 2,2'-anhydrouridine and 1-hexanethiol and incorporated into an oligodeoxyribonucleotide. The thermal stability of the duplexes formed by the 2'-S-hexyl modified ODN with either the complementary DNA or RNA strand was decreased compared to the unmodified counterparts.

Probable involvement of the 5-hydroxytryptamine(4) receptor in methotrexate-induced delayed emesis in dogs

Delayed emesis in cancer patients undergoing chemotherapy remains a significant problem. The pathogenesis of delayed emesis is still obscure. It was recently demonstrated that methotrexate (MTX), an anticancer drug, evoked delayed emesis in dogs in a manner similar to its actions in humans. We evaluated the antiemetic activity of FK1052, a potent antagonist for both the 5-hydroxytryptamine (HT)(3) and 5-HT(4) receptors, on delayed emesis induced by MTX in beagle dogs. Animal behavior was recorded for 3 days using a video camera. Delayed emesis lasting up to 72 h was observed in dogs treated with MTX (2.5 mg/kg i.v.), but acute emesis did not occur. The following antiemetics, at the dose that prevents cisplatin-induced acute emesis in dogs, were administered i.v. as multiple injections every 12 h during days 2 to 3. FK1052 (1 and 3.2 mg/kg) significantly reduced the emetic episodes caused by MTX, whereas ondansetron (1 mg/kg), a selective 5-HT(3) receptor antagonist, was not effective. The emetic episodes induced by MTX were also inhibited by another 5-HT(3/4) receptor antagonist, tropisetron (1 mg/kg). CP-122,721 (0. 1 mg/kg), a potent selective tachykinin NK(1) receptor antagonist, significantly reduced the emetic responses to MTX. Copper sulfate-induced emesis in dogs was also prevented by FK1052, tropisetron, and CP-122,721 but not by ondansetron. FK1052, tropisetron, and ondansetron had negligible affinity for the NK(1) receptor at 1 microM. These results suggest that the 5-HT(4) receptor may be in part involved in the production of delayed emesis induced by MTX in dogs and that FK1052 may be a useful drug against both acute and delayed emesis induced by cancer chemotherapy.

Stereospecific synthesis of alpha-anomeric pyrimidine nucleoside

A facile stereospecific synthetic method for alpha-anomeric 2'-deoxypyrimidine nucleoside unit utilizing aminooxazoline derivative of ribofuranose was investigated. Thus, easily accessible riboaminooxazoline derivative prepared by ribose and cyanamid was allowed to react with ethyl alpha-bromoethylacrylate to give corresponding adduct. The adduct was cyclized by strong base such as potassium t-butokiside. The resulted 2,2'-cyclonucleoside was then treated with acetyl bromide followed by n-butyltin hydride to give alpha-anomeric 3',5'-di-O-acetylthymidine. 3',5'-Di-O-acety groups of the nucleoside were easily removed by the action of excess of triethyl amine in methanol. Essentially same procedure afforded corresponding 2'-deoxyuridine, which was further, converted to alpha-anomeric 2'-deoxycytidine.

Function of the cloned putative neutral sphingomyelinase as lyso-platelet activating factor-phospholipase C

Sphingolipids such as ceramide and sphingosine have been regarded as novel signal mediators in cells. However, the mechanisms of generation of these lipids upon various stimulation remain to be elucidated. Neutral sphingomyelinase (N-SMase) is one of the key enzymes in the generation of ceramide, and recently the cloning of a putative N-SMase was reported. Because the function of the protein was unclear in the previous report, we investigated the role it plays in cells. N-SMase activity in cells overexpressing the protein with hexa-histidine tag was immunoprecipitated with anti-hexa-histidine antibody. The metabolism of ceramide and SM was not apparently affected in overexpressing cells. Radiolabeling experiments using [(3)H]palmitic acid or [(3)H]hexadecanol demonstrated an accumulation of 1-O-alkyl-sn-glycerol and a corresponding decrease of 1-alkyl-2-acyl-sn-glycero-3-phosphocholine in overexpressing cells. In vitro studies showed that both 1-acyl-2-lyso-sn-glycero-3-phosphocholine (lyso-PC) and 1-O-alkyl-2-lyso-sn-glycero-3-phosphocholine (lyso-platelet activating factor (lyso-PAF)) are good substrates of the protein. In further radiolabeling experiments, 1-acyl-lyso-PC was predominantly and equally metabolized into diacyl-PC in both vector and overexpressing cells. On the other hand, 1-O-alkyl-lyso-PC (lyso-PAF) was metabolized into both diradyl-PC and 1-O-alkyl-glycerol in overexpressing cells but only into diradyl-PC in vector cells. These results suggest that the protein acts as lyso-PAF-PLC rather than lyso-PC-PLC or N-SMase in cells.

Nonpeptide mimic of bradykinin with long-acting properties

Kinins, members of a family of peptides released from kininogens by the action of kallikreins, have been implicated in a variety of biological activities including vasodilation, increased vascular permeability, contraction of smooth muscle cells and activation of sensory neurons. However, investigation of the physiological actions of kinins have been greatly hampered because its effects are curtailed by rapid proteolytic degradation. We examined the pharmacological characteristics of the first nonpeptide bradykinin receptor agonist 8-[2,6-dichloro-3-[N-[(E)-4-(N-methylcarbamoyl)cinnamidoacetyl+ ++]-N-methylamino]benzyloxy]-2-methyl-4-(2-pyridylmethoxy)quinolin e (FR190997). FR190997, whose structure is quite different from the natural peptide ligand, but is similar to the nonpeptide antagonists FR165649, FR167344 and FR173657, potently and selectively interacts with the human B2 receptor and markedly stimulates inositol phosphate formation in transfected Chinese hamster ovary (CHO) cells. FR190997 induces concentration-dependent contraction of isolated guinea pig ileum. In vivo, FR190997 mimics the biological action of bradykinin and induces hypotensive responses in rats with prolonged duration, presumably as a consequence of its resistance to proteolytic degradation. Therefore, FR190997 is a highly potent and subtype-selective nonpeptide agonist which displays high intrinsic activity at the bradykinin B2 receptor. This compound represents a powerful tool for further investigation of the physiology and pathophysiology of bradykinin receptors.

Ceramide and sphingomyelinases in the regulation of stress responses

Ceramide and other sphingolipids are now recognized as novel intracellular signal mediators. One of the important and regulated steps in the metabolism of sphingolipids is the hydrolysis of sphingomyelin into ceramide by sphingomyelinases. Whereas some studies suggest a role for acid sphingomyelinase in cell regulation, several lines of investigation suggest that neutral sphingomyelinase (N-SMase) plays a critical role in stress responses including apoptosis. Recently the advanced purification of neutral membrane-bound magnesium-dependent sphingomyelinase from rat brain was reported on. The specific activity of the purified N-SMase was increased by approximately 3000-fold over the rat brain homogenate, and it is specifically activated by phosphatidylserine. In cells, N-SMase may be coupled to either the redox state and/or glutathione metabolism. The significance of N-SMase and ceramide in stress responses is discussed.

Discovery of orally active nonpeptide bradykinin B2 receptor antagonists

Orally active nonpeptide bradykinin (BK) B2 receptor antagonists have been discovered by using directed random screening and chemical modification. These compounds displaced [3H]BK binding to B2 receptors in guinea-pig ileum membranes, rat uterus membranes and human lung fibroblasts with nanomolar IC50s. They did not inhibit different specific radio-ligand bindings to other receptor sites including B2 receptors. In isolated guinea-pig ileum preparations, these compounds had no agonistic effect on smooth muscle contraction at 10(-6) M, and caused parallel rightward shifts of the concentration-response curves to BK on contraction with higher p A2 values. They also blocked human B2 receptor-mediated phosphatidylinositol hydrolysis without agonistic effect. In vivo, the oral administrations of these antagonists potently inhibited BK-induced bronchoconstriction in guinea-pigs. They also reduced carrageenin-induced paw edema and caerulein-induced pancreatitis in rats. Moreover, these compounds alleviated kaolin-induced pain in mice by oral administration. These results show that our compounds are potent, selective, and orally active BK B2 receptor antagonists and that they may have therapeutic potential against inflammatory diseases and pain.

Prenatal sonographic diagnosis of a fetal renal mesoblastic nephroma occurring after transfer of a cryopreserved embryo

Here we report the first case of prenatally diagnosed fetal renal mesoblastic nephroma occurring after transfer of a cryopreserved embryo. A 37 year old woman, having immunological infertility, was treated by in-vitro fertilization (IVF) and embryo transfer. Following unsuccessful IVF using fresh embryos, the patient conceived after transfer of cryopreserved-thawed embryos. The chromosomal analysis identified a normal karyotype at 16 weeks' gestation when amniocentesis was performed. The pregnancy course was uneventful until 28 weeks' gestation when polyhydramnios associated with fetal renal tumour was detected using ultrasonography. A male infant weighing 2564 g was born via Caesarean section at 34 weeks' gestation. A left nephrectomy was performed 5 days after delivery and the tumour was identified histologically as a mesoblastic nephroma. The postoperative course was uncomplicated to this point.

Immunohistological studies of metabotropic glutamate receptor subtype 6-deficient mice show no abnormality of retinal cell organization and ganglion cell maturation

Immature retinal ganglion cells (RGCs) initially show a multistratified dendritic pattern, and, during the postnatal period, these dendrites gradually monostratify into ON and OFF sublaminae. The selective agonist of group III metabotropic glutamate receptors (mGluR), L-2-amino-4-phosphonobutyrate (L-AP-4), hyperpolarizes ON bipolar cells and reduces glutamate release. On the basis of L-AP-4-evoked inhibitory effects on ON-OFF segregation of developing RGCs, it has been hypothesized that glutamate-mediated synaptic activity is crucial for formation of the ON-OFF network. Gene-targeted ablation of mGluR6 specifically expressed in ON bipolar cells blocks normal ON responses but has been predicted to enhance glutamate release from ON bipolar cells. The mGluR6 knock-out mouse therefore provides a unique opportunity to investigate whether glutamate release and ON responses are important factors in the development of ON-OFF segregation. The combination of several different morphological analyses indicates that ON bipolar cells, as well as several distinct amacrine cells, in mGluR6 knock-out mice are normally distributed and correctly extend their terminals to defined retinal laminae. Importantly, both alpha and delta RGCs in adult mGluR6 knock-out mice are found monostratified into cell type-specific layers. Furthermore, no difference between wild-type and mGluR6 knock-out mice is observed in the maturation and dendritic stratification of developing RGCs. Hence, despite a deficit in normal ON responses, mGluR6 deficiency causes no abnormality in the retinal cellular organization nor in the stratifications of both ON bipolar cells and developing and mature RGCs. Based on these findings, we discuss several possible mechanisms that may underlie ON-OFF segregation of RGCs.