Synthesis and Antiviral Evaluation of 4'-alkoxy Analogues of 9-(β-D-xylofuranosyl)adenine

Background:

Motivated by the reported biological activity of 9-(β-D-xylofuranosyl)adenine (xylo-A), the synthesis of its 4'-alkoxy analogues was carried out.

Methods:

The starting material 9-(3-deoxy-β-D-glycero-pento–3-enofuranosyl)adenine (1) was prepared from adenosine. Compound 1 was converted to the 2',5'-bis-0–(tert-butyldimethylsilyl) derivative (2) and then to the N6-pivaloyl derivative (3). When 3 was reacted with meta- chloroperbenzoic acid in the presence of a series of alcohols, the β-D-isomer of the respective 4'-alkoxy derivative was obtained exclusively in high yield. Deprotection of these products led to the isolation of the desired 4'alkoxy analogues (8a-I) of xylo-A.

Results:

Antiviral evaluation revealed that none of these analogues showed inhibitory activity against a wide variety of DNA and RNA viruses.

Conclusions:

We assume that conformational difference of the sugar moiety of 8a-1 from that of xylo-A could be attributable to their inactivity.

High-sensitivity analysis of naturally occurring sugar chains, using a novel fluorescent linker molecule

To analyse the binding of sugar chains to proteins, viruses and cells, the surface plasmon resonance (SPR) technique is very convenient and effective because it is a real-time, non-destructive detection system. Key to this method is linker compounds for immobilization of the sugar chains to the gold-coated chip for SPR. Also, well-designed fluorescent labelling reagents are essential when analysing the structure of trace amounts of sugar chains derived from natural sources, such as glycoproteins on the surface of specific cells. In this report, we developed a novel linker molecule, named 'f-mono', which has both of these properties: simple immobilization chemistry and a fluorescent label. Since the molecule contains a 2,5-diaminopyridyl group and a thioctic acid group, conjugation with sugar chains can be achieved using the well-established reductive amination reaction. This conjugate of sugar chain and fluorescent linker (fluorescent ligand-conjugate, FLC) has fluorescent properties (ex. 335 nm, em. 380 nm), and as little as 1 microg of FLC can be easily purified using HPLC with a fluorescent detector. MS and MS/MS analysis of the FLC is also possible. As a +2 Da larger MS peak ([M + H + 2](+) ion) was always associated with the theoretical MS peak ([M + H](+)) (due to the reduction of the thioctic acid moiety), the MS peaks of the FLC were easily found, even using unfractionated crude samples. Immobilization of the FLC onto gold-coated chips, and their subsequent SPR analyses were successively accomplished, as had been performed previously using non-fluorescent ligand conjugates.

Improvement of adaptive immunity by antigen-carrying biodegradable nanoparticles

One of the most important aspects in vaccine development is to induce potent antigen-specific immune responses. In this study, we examined the immunological activities of antigen-carrying biodegradable poly(gamma-glutamic acid) (gamma-PGA) nanoparticles (NPs) in mice. The immunization with ovalbumin (OVA)-carrying gamma-PGA NPs (OVA-NPs) could induce significant expansion of antigen-specific CD8(+) T cells. Unlike complete Freund's adjuvant, subcutaneous (s.c.) inoculation of OVA-NPs to footpad did not generate injection site swelling. Although OVA-NPs could induce both antigen-specific cellular and humoral immune responses, the dominant induction of either cellular or humoral immunity was found to depend on their administration routes. Strong antibody production was observed by s.c. immunization, yet no antibody was identified by intranasal immunization. Thus, gamma-PGA NPs are a safe and efficient antigen carrier with unique immunological properties.

Synthesis and anti-HIV activity of 4'-C-ethynyl-2'-deoxy-4'-thio-nucleosides

Synthesis of 4'-C-ethynyl-2'-deoxy-4'-thionucleosides was carried out based on electrophilic glycosidation using 4-C-ethynyl-4-thiofuranoid glycal. The glycal 15 was prepared as follows: oxidative cleavage of 6 with Pb(OAc)(4) forming the aldehyde 7, aldol reaction of 7 and subsequent silylation to furnish 8, conversion of the formyl group of 8 into an ethynyl group, and finally beta-elimination of the resulting 14 with t-BuLi. The glycosyl donor 16 was prepared by silyl-protection of 15. Electrophilic glycosidation was performed between silylated N(4)-acetylcytosine and 16 in the presence of N-iodosuccinimide. Radical-mediated removal of the introduced iodine atom followed by deprotection gave 4'-C-ethynyl-2'-deoxy-4'-thiocytidine (18).

High repetition rate neutron flux array using digital-signal processing and scintillators for study of high performance plasma at JT-60U

Aiming at increasing the count rate capability of the radial neutron collimator system in JT-60U, a digital-signal processing system has been extended to seven channels for data acquisition of stilbene crystal detector using analog-to-digital converters equipped with a fast flash memory. In this method, the detected pulses were postprocessed concerning pulse shape and pulse height. Using this system, the radial neutron collimator system can provide the information on the temporal evolution of emission rate of d-T neutrons and gamma rays as well as d-D neutrons. On the course of the development, the fast and stable handling of the large data around 7 GB is undertaken for a discharge.

Stratified analyses for selecting appropriate target patients with diabetic peripheral neuropathy for long-term treatment with an aldose reductase inhibitor, epalrestat

AIMS

The long-term efficacy of epalrestat, an aldose reductase inhibitor, in improving subjective symptoms and nerve function was comprehensively assessed to identify patients with diabetic peripheral neuropathy who responded to epalrestat treatment.

METHODS

Stratified analyses were conducted on data from patients in the Aldose Reductase Inhibitor-Diabetes Complications Trial (ADCT). The ADCT included patients with diabetic peripheral neuropathy, median motor nerve conduction velocity > or = 40 m/s and with glycated haemoglobin (HbA(1c)) < or = 9.0%. Longitudinal data on HbA(1c) and subjective symptoms of the patients for 3 years were analysed (epalrestat n = 231, control subjects n = 273). Stratified analyses based on background variables (glycaemic control, grades of retinopathy or proteinuria) were performed to examine the relationship between subjective symptoms and nerve function. Multiple logistic regression analyses were conducted.

RESULTS

Stratified subgroup analyses revealed significantly better efficacy of epalrestat in patients with good glycaemic control and less severe diabetic complications. In the control group, no improvement in nerve function was seen regardless of whether symptomatic benefit was obtained. In the epalrestat group, nerve function deteriorated less or improved in patients whose symptoms improved. The odds ratio of the efficacy of epalrestat vs. control subjects was approximately 2 : 1 (4 : 1 in patients with HbA(1c) < or = 7.0%).

CONCLUSION

Our results suggest that epalrestat, an aldose reductase inhibitor, will provide a clinically significant means of preventing and treating diabetic neuropathy if used in appropriate patients.

Nickel-63 production in copper samples exposed to the Hiroshima atomic bomb: estimation based on an excitation function obtained by neutron irradiation experiments

The upper and lower limits of the excitation function of the (63)Cu(n,p)(63)Ni reaction were experimentally determined, and the number of (63)Ni nuclei produced in copper samples exposed to atomic bomb neutrons in Hiroshima was estimated by using the experimental excitation functions and the neutron fluences given in the DS02 dosimetry system. The estimated number of (63)Ni nuclei was compared with that measured and with that calculated using the DS02 dosimetry system and the corresponding ENDF/B-VI cross section. In comparison with DS02, there is about a 60% maximum difference in (63)Ni production at the hypocenter when the experimental upper cross section values are used. The difference becomes smaller at greater distances from the hypocenter and decreases, for example, to less than 30 and 5% when using the upper and lower experimental cross sections at 1,000 m, respectively.

Excitation function for 63Cu(n,p)63Ni reaction in neutron energy range up to 15 MeV

The excitation function for the (63)Cu(n,p)(63)Ni reaction has been measured by activation method using the 4.5 MV Dynamitron accelerator of the Fast Neutron Laboratory of Tohoku University. Copper plates and hollow spherical copper shells were irradiated by neutrons of various energy up to 14.9 MeV produced by the T(p,n), D(d,n), and T(d,n) reactions. The (63)Ni produced in the irradiated copper target was chemically separated. The beta-rays emitted from the extracted (63)Ni were measured by a liquid scintillation method. The cross sections obtained were compared with the evaluated data files of JENDL-3.3, ENDF/B-VI and FENDL/A-2.0. Consequently, it is found that FENDL/A-2.0 is consistent with our experimental data in the energy range studied in this work. The effect of proton shell appeared in the excitation function obtained is also discussed.

Potent and selective inhibition of Tat-dependent HIV-1 replication in chronically infected cells by a novel naphthalene derivative JTK-101

In search for effective human immunodeficiency virus type 1 (HIV-1) transcription inhibitors, we have evaluated more than 100,000 compounds for their inhibitory effects on HIV-1 long terminal repeat (LTR)-driven reporter gene expression, and identified a novel naphthalene derivative, JTK-101. This compound could suppress tumour necrosis factor (TNF)-alpha-induced HIV-1 production in latently infected OM-10.1 cells at nanomolar concentrations. JTK-101 could also potently inhibit constitutive HIV-1 production in MOTL-4/IIIB. However, the antiviral activity of JTK-101 was found to be much weaker in acutely infected cells and the chronically infected cells U937/IIIB cells than in OM-10.1 and MOLT-4/IIIB cells. JTK-101 selectively suppressed TNF-alpha-induced HIV-1 mRNA synthesis in OM-10.1 cells in a dose-dependent fashion. JTK-101 modestly inhibited TNF-alpha-induced HIV-1 LTR-driven reporter gene expression, but potently inhibited Tat-induced gene expression. Immunoblot analysis revealed that low-level expression of the Tat cofactors CDK9 and cyclin T1 might contribute to the diminished antiviral activity in U937/IIIB cells. Furthermore, JTK-101 could not inhibit HIV-1 replication in chronically infected monocytes/macrophages, in which CDK9 and cyclin T1 were undetectable. These results suggest that JTK-101 exerts its anti-HIV-1 activity through the inhibition of known or unknown Tat cofactors, presumably CDK9/cyclin T1.

Gamma-carboline derivatives with anti-bovine viral diarrhea virus (BVDV) activity

Based on anti-viral screening of our heteroaromatics derived from thalidomide, the gamma-carboline skeleton has been identified as a superior scaffold structure for compounds with potent anti-bovine viral diarrhea virus (BVDV) activity. Structural development studies led to a potent anti-viral agent, SK5M (5-methyl-gamma-carboline), with the EC(50) of 0.26 microM.

Synthesis and antiviral evaluation of (+/-)-4'-ethynyl-5'-difluorocarbocyclic-d4T analogue

Synthesis of (+/-)-4'-ethynyl-5'-difluorocarbocyclic-d4T analogue 8, in which the furanose ring oxygen of usual nucleosides is replaced with a geminal-difluoromethylidene group, was carried out. Electrophilic fluorination with Selectfluor was applied to construct a gem-difluorocyclopentenone system to give 12. Regioselective introduction of thymine base was performed under the Mitsunobu conditions by employing the 4-methoxycarbonyl derivative 13. Antiviral evaluation of 8 was also examined.

A fast response and gamma-insensitive neutron detector based on parallel-plate avalanche counter

The use of the parallel-plate avalanche counter for slow-neutron counting is described. The choice of a suitable neutron converter is discussed on the basis of Monte Carlo simulation, and some experimental results are shown. Excellent gamma-insensitivity, high rate capability, possibility of construction in large sensitive area and low production cost are among the promising features of this neutron detector.

Intracellular metabolism and persistence of the anti-human immunodeficiency virus activity of 2',3'-didehydro-3'-deoxy-4'-ethynylthymidine, a novel thymidine analog

The therapeutic benefits of current antiretroviral therapy are limited by the evolution of drug-resistant virus and long-term toxicity. Novel antiretroviral compounds with activity against drug-resistant viruses are needed. 2',3'-didehydro-3'-deoxy-4'-ethynylthymidine (4'-Ed4T), a novel thymidine analog, has potent anti-human immunodeficiency virus (HIV) activity, maintains considerable activity against multidrug-resistant HIV strains, and is less inhibitory to mitochondrial DNA synthesis in cell culture than its progenitor stavudine (D4T). We investigated the intracellular metabolism and anti-HIV activity of 4'-Ed4T. The profile of 4'-Ed4T metabolites was qualitatively similar to that for zidovudine (AZT), with the monophosphate metabolite as the major metabolite, in contrast to that for D4T, with relatively poor formation of total metabolites. The first phosphorylation step for 4'-Ed4T in cells was more efficient than that for D4T but less than that for AZT. The amount of 4'-Ed4T triphosphate (4'-Ed4TTP) was higher than that of AZTTP at 24 h in culture. There was a dose-dependent accumulation of 4'-Ed4T diphosphate and 4'-Ed4TTP on up-regulation of thymidylate kinase and 3-phosphoglycerate kinase expression in Tet-On RKO cells, respectively. The anti-HIV activity of 4'-Ed4T in cells persisted even after 48 h of drug removal from culture in comparison with AZT, D4T, and nevirapine (NVP). The order of increasing persistence of anti-HIV activity of these compounds after drug removal was 4'-Ed4T > D4T > AZT > NVP. In conclusion, with the persistence of 4'-Ed4TTP and persistent anti-HIV activity in cells, we anticipate less frequent dosing and fewer patient compliance issues than for D4T. 4'-Ed4T is a promising antiviral candidate for HIV type 1 chemotherapy.

Protein direct delivery to dendritic cells using nanoparticles based on amphiphilic poly(amino acid) derivatives

Induction of an adaptive immune response by vaccination is possible for a broad range of infectious diseases or cancers. Antigen-loaded polymeric nanoparticles have recently been shown to possess significant potential as vaccine delivery systems and adjuvants. Here we demonstrate the use of nanoparticles composed of amphiphilic poly(amino acid) derivatives as vaccine adjuvants. We prepared protein-loaded, biodegradable nanoparticles composed of hydrophobically modified poly(gamma-glutamic acid) (gamma-PGA). gamma-PGA hydrophobic derivatives (gamma-hPGA) formed 200 nm-sized nanoparticles in water. The protein-encapsulated gamma-hPGA nanoparticles were efficiently taken up by immature dendritic cells (iDCs). Interestingly, the nanoparticle uptake by iDCs induced DC maturation. The immunization with human immunodeficiency virus (HIV)-1 gp120-encapsulated nanoparticles strongly induced antigen-specific cellular immunity. These results suggest that antigen-loaded gamma-hPGA nanoparticles provide a novel delivery tool for vaccination against viral infections or tumors. This system has potential application as a universal delivery system for protein-based vaccines capable of inducing cytotoxic T lymphocyte (CTL).

Carbon tetrachloride as a thermoporometry liquid probe to study the cross-linking of styrene copolymer networks

Mesh size distributions (MSDs) of swollen cross-linked styrene copolymer networks have been measured by thermoporometry using CCl(4) as a probe liquid. All numerical relationships required for the calculation of the MSD were established for both the liquid-to-solid and the solid-to-solid thermal transitions of CCl(4) and successfully validated on test samples. It was found that the polymer network, for both thermally and photo-cross-linked materials, was completely built in about 4 h of exposure. A clear correlation was established between the average mesh size of the swollen polymer network on one hand and the benzoyl peroxide groups content and swelling ratio on the other hand.

Induction of potent CD8+ T-cell responses by novel biodegradable nanoparticles carrying human immunodeficiency virus type 1 gp120

The mainstream of recent anti-AIDS vaccines is a prime/boost approach with multiple doses of the target DNA of human immunodeficiency virus type 1 (HIV-1) and recombinant viral vectors. In this study, we have attempted to construct an efficient protein-based vaccine using biodegradable poly(gamma-glutamic acid) (gamma-PGA) nanoparticles (NPs), which are capable of inducing potent cellular immunity. A significant expansion of CD8+ T cells specific to the major histocompatibility complex class I-restricted gp120 epitope was observed in mice intranasally immunized once with gp120-carrying NPs but not with gp120 alone or gp120 together with the B-subunit of cholera toxin. Both the gp120-encapsulating and -immobilizing forms of NPs could induce antigen-specific spleen CD8+ T cells having a functional profile of cytotoxic T lymphocytes. Long-lived memory CD8+ T cells could also be elicited. Although a substantial decay in the effector memory T cells was observed over time in the immunized mice, the central memory T cells remained relatively constant from day 30 to day 238 after immunization. Furthermore, the memory CD8+ T cells rapidly expanded with boosting with the same immunogen. In addition, gamma-PGA NPs were found to be a much stronger inducer of antigen-specific CD8+ T-cell responses than nonbiodegradable polystyrene NPs. Thus, gamma-PGA NPs carrying various HIV-1 antigens may have great potential as a novel priming and/or boosting tool in current vaccination regimens for the induction of cellular immune responses.

Selective inhibition of porcine endogenous retrovirus replication in human cells by acyclic nucleoside phosphonates

Several anti-human immunodeficiency virus type 1 reverse transcriptase inhibitors were evaluated for their antiviral activities against porcine endogenous retrovirus in human cells. Among the test compounds, zidovudine was found to be the most active. The order of potency was zidovudine > phosphonylmethoxyethoxydiaminopyrimidine = phosphonylmethoxypropyldiaminopurine > tenofovir > or = adefovir > stavudine.

Identification and characterization of Birt-Hogg-Dubé associated renal carcinoma

The Birt-Hogg-Dubé (BHD) gene is responsible for BHD syndrome, a rare autosomal dominant disease, characterized by benign hair follicle tumours, spontaneous pneumothorax and renal neoplasms with diverse histology. To elucidate its involvement in the development of renal neoplasms, we examined a total of 100 sporadic renal tumours with various histological subtypes for BHD mutation by SSCP-sequencing analyses. We found one germline insertion mutation in the C8 hotspot of exon 11 (c.1733insC), which is known to have a strong association with renal tumour occurrence. The germline-mutated patient suffered from solitary renal cell carcinoma (RCC) but did not have any other BHD manifestations or family history. The tumour revealed heterogeneous cytomorphology, mainly a mixture of eosinophilic and focally clear cells with tubulopapillary architecture. In this tumour, both BHD alleles were inactivated by germline mutation concomitant with loss of heterozygosity, and the amount of BHD mRNA detected by real-time quantitative PCR (RQ-PCR) was very low. Renal tumour subtype/nephron segment-specific gene expression detected by RQ-PCR demonstrated that the tumour expressed relatively high amounts of alpha-methylacyl-CoA racemase (AMACR) and the KIT oncogene, but relatively low amounts of carbonic anhydrase IX (CA9), aquaporin 1 (AQP1), claudin 7 (CLDN7), parvalbumin (PVALB), chloride channel Kb (CLCNKB) and 11-beta-hydroxysteroid dehydrogenase 2 (HSD11B2), suggesting diverse mRNA signatures. Further clustering analysis of 88 renal tumours based on expression of these eight genes sub-classified the tumour as close to oncocytomas and chromophobe RCCs, which are considered distal nephron-associated tumours. These data suggest that somatic mutation of BHD is relatively rare in Japanese patients. The BHD-mutated RCC identified in this study, which exhibits heterogeneous biological features in both morphology and gene expression signatures, seems to deviate from our current understanding of renal tumour classification.

Targeting of antigen to dendritic cells with poly(gamma-glutamic acid) nanoparticles induces antigen-specific humoral and cellular immunity

Nanoparticles are considered to be efficient tools for inducing potent immune responses by an Ag carrier. In this study, we examined the effect of Ag-carrying biodegradable poly(gamma-glutamic acid) (gamma-PGA) nanoparticles (NPs) on the induction of immune responses in mice. The NPs were efficiently taken up by dendritic cells (DCs) and subsequently localized in the lysosomal compartments. gamma-PGA NPs strongly induced cytokine production, up-regulation of costimulatory molecules, and the enhancement of T cell stimulatory capacity in DCs. These maturational changes of DCs involved the MyD88-mediated NF-kappaB signaling pathway. In vivo, gamma-PGA NPs were preferentially internalized by APCs (DCs and macrophages) and induced the production of IL-12p40 and IL-6. The immunization of mice with OVA-carrying NPs induced Ag-specific CTL activity and Ag-specific production of IFN-gamma in splenocytes as well as potent production of Ag-specific IgG1 and IgG2a Abs in serum. Furthermore, immunization with NPs carrying a CD8(+) T cell epitope peptide of Listeria monocytogenes significantly protected the infected mice from death. These results suggest that Ag-carrying gamma-PGA NPs are capable of inducing strong cellular and humoral immune responses and might be potentially useful as effective vaccine adjuvants for the therapy of infectious diseases.

Comparison of the phosphorylation of 4'-ethynyl 2',3'-dihydro-3'-deoxythymidine with that of other anti-human immunodeficiency virus thymidine analogs

Thymidine analogs, including 3'-azido-3'-deoxythymidine (AZT) and 2',3'-dideoxy-3'-deoxythymidine (D4T), are important antiretroviral agents. To exert antiretroviral activity, these analogs undergo a stepwise phosphorylation intracellularly to the active triphosphate metabolites. We previously reported that 4'-substituted D4T with an ethynyl group (i.e., 4'-ethynyl D4T) increased the anti-human immunodeficiency virus (HIV) activity and was active against multidrug-resistant HIV strains. 4'-Ethynyl D4T is a better substrate for phosphorylation by human thymidine kinase 1 than D4T is. In this report, we first studied the enzymes involved in the phosphorylation of 4'-ethynyl D4T from monophosphate to triphosphate metabolites. The 4'-ethynyl D4TMP is phosphorylated by recombinant human TMP kinase with a K(m) of 19 +/- 4 microM and a k(cat) of 0.007 +/- 0.001 s(-1); the relative efficiency is about 9 and 15% of those of D4TMP and AZTMP, respectively. Several enzymes from crude cellular extracts, including nucleoside diphosphate kinase, pyruvate kinase, creatine kinase, and 3-phosphoglycerate kinase, could phosphorylate 4'-ethynyl D4T-diphosphate. The relative phosphorylation efficiencies of 4'-ethynyl D4TDP were about 3 to 25% of those of D4TDP and were generally similar to those of AZTDP. In T-lymphoid cell lines, there was a preponderant accumulation of 4'-ethynyl D4TMP, suggesting that TMP kinase could be the rate-limiting enzyme in the metabolism of 4'-ethynyl D4T. Although the same enzymes are involved in the stepwise phosphorylation of thymidine analogs, their behaviors in phosphorylating metabolites of 4'-ethynyl D4T are different from those of D4T and AZT. Qualitatively, the metabolism of 4'-ethynyl D4T is more similar to that of AZT than to that of its progenitor, D4T.

Synthesis and anti-human immunodeficiency virus activity of 4'-branched (+/-)-4'-thiostavudines

Motivated by our recent finding that 4'-ethynylstavudine (4) is a promising anti-human immunodeficiency virus type 1 (HIV-1) agent, we synthesized its 4'-thio analogue, as well as other 4'-thiostavudines having a carbon substituent at the 4'-position, as racemates in this study. Methyl 3-oxo-tetrahydrothiophen-2-carboxylate (5) was used as a starting material to construct the requisite 4-thiofuranoid glycal (13). Introduction of a thymine base was carried out by an electrophilic addition reaction to 13 using N-iodosuccinimide (NIS) and bis(trimethylsilyl)thymine. The desired beta-anomer (16beta) obtained as a major product in this reaction underwent ready elimination with activated Zn to give the 4'-carbomethoxy derivative (18). By using 18 as a common intermediate, 4'-carbon-substituted (CH2OH, CO2Me, CONH2, CH=CH2, CN, and C(triple bond)CH) 4'-thiostavudines were prepared. Among these six compounds, 4'-cyano (28) and 4'-ethynyl (29) analogues were found to show inhibitory activity against HIV-1 with ED50 values of 7.6 and 0.74 microM, respectively. The activity of 29 was comparable to that of stavudine, but 29 was not as active as 4. Optical resolution of 29 was briefly examined.

Development of Vaccine Adjuvants Using Polymeric Nanoparticles and Their Potential Applications for Anti-HIV Vaccine

The development of a prophylactic/therapeutic HIV-1 vaccine based on recombinant proteins is needed for the control of the worldwide AIDS epidemic. Subunit protein and peptide vaccines are generally very safe, with well-defined components. However, these antigens are often poorly immunogenic, and thus require the use of adjuvants to induce adequate immunity. Particulate adjuvants (e.g. micro/nanoparticles, emulsions, ISCOMS, liposomes, virosomes, and virus-like particles) have been widely investigated as HIV-1 vaccine delivery systems. Antigen uptake by antigen-presenting cells (APC) is enhanced by the association of the antigens with polymeric micro/nanoparticles. The adjuvant effect of micro/nanoparticles appears to largely be a consequence of their uptake into APC. More importantly, particulate antigens have been shown to be more efficient than soluble antigens for the induction of immune responses. Over the past two decades, we have studied the synthesis and clinical applications of core-corona polymeric nanospheres composed of hydrophobic polystyrene and hydrophilic macromonomers. Core-corona type polymeric nanospheres have applications in various technological and biomedical fields, because their chemical structures and particle size can be easily controlled. In this study, we focused on the development of a HIV-1 vaccine using polymeric nanoparticles. We evaluated the immunization strategies for HIV-1-capturing core-corona type polystyrene nanospheres that would efficiently induce HIV-1-specific IgA responses in female mice and the macaque genital tract. Moreover, based on this research, we attempted to develop novel biodegradable nanoparticles composed of poly (gamma-glutamic acid) (gamma-PGA) for protein-based vaccine delivery. These HIV-1-capturing nanospheres and protein-loaded gamma-PGA nanoparticles have shown unique potential as vaccine carriers.

An ultra fast, radiation-resistant fast neutron detector

This paper describes a study on 14-MeV neutron detection based on the combination of a parallel plate avalanche chamber with a sheet of polypropylene as fast neutron-to-charged-particle converter. By employing a carefully shielded chamber, neutron-induced charged particles background from the chamber body was successfully reduced to <6 x 10(-5) count per incident neutron. Fast signals, with approximately 7 ns pulse width were observed. The obtained detection efficiency is 0.15%.

Fast response neutron emission monitor for fusion reactor using stilbene scintillator and Flash-ADC

The stilbene neutron detector which has been used for neutron emission profile monitoring in JT-60U has been improved, to respond to the requirement to observe the high-frequency phenomena in megahertz region such as toroidicity-induced Alfvén Eigen mode in burning plasma as well as the spatial profile and the energy spectrum. This high-frequency phenomenon is of great interest and one of the key issues in plasma physics in recent years. To achieve a fast response in the stilbene detector, a Flash-ADC is applied and the wave form of the anode signal stored directly, and neutron/gamma discrimination was carried out via software with a new scheme for data acquisition mode to extend the count rate limit to MHz region from 1.3 x 10(5) neutron/s in the past, and confirmed the adequacy of the method.

Differential cross sections of neutron-induced fragment-emission reactions for a microdosimetry study

Experimental differential cross sections of fragment emission (p, d, t, alpha, Li, Be and B), which were obtained for tens of mega electron volt neutrons on carbon and aluminum, using a counter telescope array and a Bragg-curve counter specially developed for neutron-induced reactions, are presented and compared with theoretical calculations using various reaction models. A calculation with the ISOBAR and GEM models was found to reproduce the experimental data except for an underestimation in non-vaporation processes. Calculations of the energy deposition by neutrons in a thin silicon layer show significant differences among the model employed.

Installation and application of an intense 7Li(p,n) neutron source for 20-90 MeV region

An intense (7)Li(p,n) neutron source was installed with the K = 110-MeV azimuthally varying field (AVF) cyclotron at the Cyclotron and Radioisotope Center (CYRIC), Tohoku University, by employing a special arrangement to allow a short target-sample distance down to 1 m. The source can deliver a neutron flux around 1.5 x 10(6) n cm(-2) s(-1) with a lithium target of thickness equivalent to 2-MeV energy loss and 3-microA proton beam, which is the highest intensity in the world. The source is successfully used for (1) measurement of neutron cross sections relevant to radiation safety and radiation effect and (2) semiconductor irradiation test for single-event effect and (3) characterisation of neutron detectors and dosemeters.

Isolation and characterization of human immunodeficiency virus type 1 resistant to the small-molecule CCR5 antagonist TAK-652

TAK-652, a novel small-molecule chemokine receptor antagonist, is a highly potent and selective inhibitor of CCR5-using (R5) human immunodeficiency virus type 1 (HIV-1) replication in vitro. Since TAK-652 is orally bioavailable and has favorable pharmacokinetic profiles in humans, it is considered a promising candidate for an entry inhibitor of HIV-1. To investigate the resistance to TAK-652, peripheral blood mononuclear cells were infected with the R5 HIV-1 primary isolate KK and passaged in the presence of escalating concentrations of the compound for more than 1 year. After 67 weeks of cultivation, the escape virus emerged even in the presence of a high concentration of TAK-652. This virus displayed more than 200,000-fold resistance to TAK-652 compared with the wild type. The escape virus appeared to have cross-resistance to the structurally related compound TAK-779 but retained full susceptibility to TAK-220, which is from a different class of CCR5 antagonists. Furthermore, the escape virus was unable to use CXCR4 as a coreceptor. Analysis for Env amino acid sequences of escape viruses at certain points of passage revealed that amino acid changes accumulated with an increasing number of passages. Several amino acid changes not only in the V3 region but also in other Env regions seemed to be required for R5 HIV-1 to acquire complete resistance to TAK-652.

Highly selective action of triphosphate metabolite of 4'-ethynyl D4T: a novel anti-HIV compound against HIV-1 RT

2',3'-Didehydro-3'-deoxy-4'-ethynylthymidine (4'-Ed4T), is a recently discovered nucleoside reverse transcriptase inhibitor (NRTI) showing a 5- to 10-fold greater anti-human immunodeficiency virus type 1 (HIV-1) activity and less cellular and mitochondrial toxicity than its parental compound, stavudine (D4T). It is also active against a variety of NRTI-resistant HIV-1 mutants under non-cytotoxic concentrations. In this study, the effects of 4'-Ed4TTP, which is the triphosphate metabolite of 4'-Ed4T, on HIV-1 reverse transcriptase (RT) activity were investigated. We found that 4'-Ed4TTP was a substrate of HIV-1 RT serving as a DNA chain terminator, and it inhibited the DNA polymerase activity of RT more efficiently than D4TTP. The value of Ki(4'-Ed4TTP)/Km(dTTP) is 0.15 for DNA/RNA primer/template duplex (P/T), but 0.7 for DNA/DNA P/T, suggesting 4'-Ed4TTP inhibits RT more efficiently during RNA-dependent DNA synthesis than DNA-dependent DNA synthesis. 4'-Ed4TTP was also found to inhibit the 3TC (Lamivudine)-resistant RT mutant, M184V, with 3-fold less efficiency than the wild type (wt) RT. 4'-Ed4TTP showed much less inhibitory effects toward major host DNA polymerases. Overall, our results suggest that 4'-Ed4TTP is the active form for anti-HIV-1 activity via its inhibitory effect against RT.

The role of G-protein-coupled receptor kinase 5 in pathogenesis of sporadic Parkinson's disease

Sporadic Parkinson's disease (sPD) is a common neurodegenerative disorder, characterized by selective degeneration of dopaminergic neurons in the substantia nigra. Although the pathogenesis of the disease remains undetermined, phosphorylation of alpha-synuclein and its oligomer formation seem to play a key role. However, the protein kinase(s) involved in the phosphorylation in the pathogenesis of sPD has not been identified. Here, we found that G-protein-coupled receptor kinase 5 (GRK5) accumulated in Lewy bodies and colocalized with alpha-synuclein in the pathological structures of the brains of sPD patients. In cotransfected cells, GRK5 phosphorylated Ser-129 of alpha-synuclein at the plasma membrane and induced translocation of phosphorylated alpha-synuclein to the perikaryal area. GRK5-catalyzed phosphorylation also promoted the formation of soluble oligomers and aggregates of alpha-synuclein. Genetic association study revealed haplotypic association of the GRK5 gene with susceptibility to sPD. The haplotype contained two functional single-nucleotide polymorphisms, m22.1 and m24, in introns of the GRK5 gene, which bound to YY1 (Yin Yang-1) and CREB-1 (cAMP response element-binding protein 1), respectively, and increased transcriptional activity of the reporter gene. The results suggest that phosphorylation of alpha-synuclein by GRK5 plays a crucial role in the pathogenesis of sPD.

New filarial nematode from Japanese serows (Naemorhedus crispus: Bovidae) close to parasites from elephants

A new onchocercid species, Loxodontofilaria caprini n. sp. (Filarioidea: Nematoda), found in subcutaneous tissues of 37 (33%) of 112 serows (Noemorhedus crispus) examined in Japan, is described. The female worm had the characteristics of Loxodontofilaria, e.g., the large body size, well-developed esophagus with a shallow buccal cavity, and the long tail with three caudal lappets. The male worm of the new species, which was first described in the genus, had unequal length of spicules, 10 pairs of pre- and post-caudal papillae, and three terminal caudal lappets. Deirids were present in both sexes. Among four species of the genus loxodontofiloria: one from the hippopotamus and three from the Elepantidae, L. caprini n. sp. appears close to L. asiatica Bain, Baker & Chabaud, 1982, a subcutaneous parasite of Elephas indicus in Myanmar (Burma). However, L. caprini n. sp. is distinct from L. asiatica in that the Japanese female worm has an esophagus half as long and the microfilariae also half as long with a coiled posterior. The microfilariae were found in the skin of serows. The new parasite appears to clearly illustrate a major event in the evolution of onchocercids: the host-switching. This might have occurred on the Eurasian continent, where elephantids and the lineage of rupicaprines diversified during the Pliocene-Pleistocene, or in Japan, into which some of these hosts migrated.