Experimental studies of the deuteron-induced activation cross-sections on natAg

Excitation functions were measured for the (nat)Ag(d,x)(105,106m,110m)Ag, (nat)Ag(d,x)(107,109)Cd and (27)Al(d,x)(24)Na reactions by the stacked-foil activation technique and high-resolution gamma-spectroscopy over the energy range 0.44-40 MeV. The thick target integral yields were deduced using the measured cross-sections. No experimental data on the (nat)Ag+d process are available in the literature above 27 MeV. The nuclides (105)Ag, (106m)Ag and (109)Cd produced with deuteron induced activation of natural silver have suitable yields and decay characteristics important for thin layer activation (TLA) analysis. The cross-section for the production of (107)Cd and (109)Cd is significantly large. Therefore, the Ag+d process can be an efficient route for the production of isotope with a medium energy accelerator. The results of the model calculation using the TALYS code are not consistent with the present data. A large shift in the incident energy is found in TALYS calculations.

Recent status of HIV-1 gene expression inhibitors

Human immunodeficiency virus type 1 (HIV-1) gene expression and transcription is a crucial step in the viral replication cycle, which is considered to be a potential target for inhibition of HIV-1. Among the factors involved in this step, the cellular protein nuclear factor (NF)-kappaB is the most powerful inducer of HIV-1 gene expression. On the other hand, the viral protein Tat plays a central role in sustaining a high level of HIV-1 replication. Several compounds have been reported to selectively inhibit the functions of Tat and NF-kappaB. Tat inhibitors target either the Tat/TAR RNA interaction or the Tat cofactor cyclin-dependent kinase 9/cyclin T1. Antioxidants, protein kinase C inhibitors, and IkappaB kinase inhibitors are known to suppress the activation of NF-kappaB. Although some of the compounds inhibit HIV-1 replication in cell cultures at low concentrations, they also have considerable toxicity to the host cells. Considering the increase of treatment failure cases in highly active antiretroviral therapy due to the emergence of multidrug resistance, HIV-1 gene expression inhibitors should be extensively studied as alternative approach to effective anti-HIV-1 chemotherapy.

In Situ Kinetics Study of the Accelerated Aging of Poly(ethylene oxide) Using PhotoDSC

PhotoDSC has been applied to follow the global kinetics of chain scissions resulting from the UV light irradiation or from the thermal degradation of a high molecular weight PEO (4 x 10(6) g x mol(-1)). Infrared spectroscopy, XRD measurements and rheology experiments were performed to evidence the occurrence of chain scissions. Melting energy was used as a tool to quantify the extent of the degradation. It was found that the chain scissions reaction follows a first-order kinetic law for both photo and thermal degradation. The activation energies were found identical in both cases (41 kJ x mol(-1)), whereas the degradation rate was higher in the case of UV irradiation than in the case of thermoageing.

Discovery of a piperidine-4-carboxamide CCR5 antagonist (TAK-220) with highly potent Anti-HIV-1 activity

We incorporated various polar groups into previously described piperidine-4-carboxamide CCR5 antagonists to improve their metabolic stability in human hepatic microsomes. Introducing a carbamoyl group into the phenyl ring of the 4-benzylpiperidine moiety afforded the less lipophilic compound 5f, which possessed both high metabolic stability and good inhibitory activity of HIV-1 envelope-mediated membrane fusion (IC(50) = 5.8 nM). Further optimization to increase potency led to the discovery of 1-acetyl-N-{3-[4-(4-carbamoylbenzyl)piperidin-1-yl]propyl}-N-(3-chloro-4-methylphenyl)piperidine-4-carboxamide (5m, TAK-220), which showed high CCR5 binding affinity (IC(50) = 3.5 nM) and potent inhibition of membrane fusion (IC(50) = 0.42 nM), as well as good metabolic stability. Compound 5m strongly inhibited the replication of CCR5-using HIV-1 clinical isolates in human peripheral blood mononuclear cells (mean EC(50) = 1.1 nM, EC(90) = 13 nM) and exhibited a good pharmacokinetic profile in monkeys (BA = 29%). This compound has been chosen as a clinical candidate for further development.

Association of transforming growth factor-beta 1 functional polymorphisms with natural clearance of hepatitis C virus

Transforming growth factor (TGF)-beta 1 suppresses the proliferation and cytotoxicity of natural killer (NK) cells, which play critical roles in resolving hepatitis C virus (HCV) infection, especially during the acute phase. We examined 230 anti-HCV antibody-positive subjects for HCV RNA and the -509T/C genotype in the TGF-beta 1 gene promoter. The -509CC genotype and the -509C allele were significantly associated with higher HCV clearance rates (P=.01) and with lower transcriptional activity. The genetic effect remained significant even after adjustment for a history of transfusion. Low TGF- beta 1 producers might have less suppression of NK cells and be more likely to resolve HCV infection.

Transbronchial Fine Needle Aspiration Cytological Examination: A Useful Tool for Diagnosing Primary Lung Cancer

BACKGROUND

Obtaining a definitive preoperative diagnosis plays a critical role in deciding upon the treatment approach for lung carcinoma. However, success in making definitive diagnoses of small primary lung cancers will require new approaches because these cancers are difficult to detect using standard biopsy procedures.

METHODS

We evaluated the results of morphologic definitive diagnosis together with various clinical factors in 1003 primary lung cancers resected surgically. Patients underwent transbronchial brushing, fine needle aspiration cytology, forceps biopsy, and/or forceps biopsy-stamp cytology for preoperative diagnoses, in conjunction with the use of Diff-Quik to confirm that hits had been made on the radiographic shadows before terminating the examinations.

RESULTS

Sensitivities of the diagnostic procedures for primary lung cancers were as follows: 64.8% for brushing, 56.1% for transbronchial forceps biopsy, 72.0% for transbronchial forceps biopsy-stamp cytology, and 86.4% for transbronchial fine needle aspiration. The four transbronchial biopsy procedures had a combined overall sensitivity of 92.7%. In patients with peripheral lung cancers of 2 cm or less in diameter, transbronchial fine needle aspiration had a sensitivity of 75.9%, which was the highest sensitivity for all transbronchial examinations. In the subset of 296 patients who underwent all four transbronchial biopsy examinations, transbronchial fine needle aspiration had the highest sensitivity of preoperative diagnosis of all the transbronchial examination methods.

CONCLUSIONS

The sensitivity of preoperative cytological diagnosis for primary lung cancers, especially transbronchial aspiration cytology, is high. Transbronchial fine needle aspiration cytology is useful for the preoperative diagnosis of primary lung cancer.

Highly Potent and Orally Active CCR5 Antagonists as Anti-HIV-1 Agents: Synthesis and Biological Activities of 1-Benzazocine Derivatives Containing a Sulfoxide Moiety

Chemical modification has been performed on an orally bioavailable and potent CCR5 antagonist, sulfoxide compound 4, mainly focusing on replacement of the [6,7]-fused 1-benzazepine nucleus. We designed, synthesized, and evaluated the biological activities of ring-expanded [6,8]-, [6,9]-, and [6,10]-fused compounds containing S-sulfoxide moieties, which led to the discovery of 1-benzazocine and 1-benzazonine compounds that exhibited potent inhibitory activities (equivalent to compound 4) in a binding assay. In addition, 1-benzazocine compounds possessing the S-sulfoxide moiety ((S)-(-)-5a,b,d,e) showed greater potency than compound 4 in a fusion assay. From further investigation in a multi-round infection assay, it was found that 1-isobutyl-1-benzazocine compound (S)-(-)-5b, containing the S-{[(1-propyl-1H-imidazol)-5-yl]methyl}sulfinyl group, showed the most potent anti-HIV-1 activity (IC90=0.81 nM, in MOLT4/CCR5 cells). Compound (S)-(-)-5b (TAK-652) also inhibited the replication of six macrophage-tropic (CCR5-using or R5) HIV-1 clinical isolates in peripheral blood mononuclear cells (PBMCs) (mean IC90=0.25 nM). It was also absorbed after oral administration in rats, dogs, and monkeys and was thus selected as a clinical candidate. The synthesis and biological activity of the 1-benzazocine compound (S)-(-)-5b and its related derivatives are described.

Induction of thymidine phosphorylase expression by AZT contributes to enhancement of 5'-DFUR cytotoxicity

Thymidine phosphorylase (TP) regulates intracellular thymidine metabolism and can enhance the anti-tumor effectiveness of 5'-deoxy-5-fluorouridine (5'-DFUR) by conversion of the pro-drug 5'-DFUR to 5-fluorouracil (5-FU) in tumor tissues. 5'-DFUR is an effective anti-tumor drug in cells expressing high levels of TP. 3'-Azido 3'-deoxythymidine (AZT) is a thymidine analog that has been proven useful in the treatment of acquired immunodefiency syndrome (AIDS). In this study, we found that AZT induces TP expression and enhances the sensitivity of human myeloid leukemia U937 cells to 5'-DFUR. Both the protein level and the activity of TP in U937 cells were elevated for 48h after exposure to AZT (20, 100 or 300muM). AZT enhanced TP promoter activity in a dose-dependent manner. AZT also increased TP mRNA levels in U937 cells as assayed by Real-time reverse-transcription PCR. AZT enhanced the cytotoxic effect of 5'-DFUR on U937 cells. A TP inhibitor, TPI, abrogated the cytotoxic activity of 5'-DFUR, and attenuated the combined cytotoxicity of AZT and 5'-DFUR. These results suggest that AZT enhances the cytotoxic effect of 5'-DFUR on U937 cells by upregulating TP activity in addition to its inhibition of thymidine kinase (TK) activity and reduction of intracellular dTTP pools.

TAK-652 inhibits CCR5-mediated human immunodeficiency virus type 1 infection in vitro and has favorable pharmacokinetics in humans

The first small-molecule CCR5 antagonist, TAK-779, could not be developed as an anti-human immunodeficiency virus type (anti-HIV-1) agent because of its poor oral bioavailability. TAK-652 is an orally bioavailable TAK-779 derivative with potent anti-HIV-1 activity. TAK-652 inhibited the binding of RANTES (regulated on activation, normal T-cell expressed and secreted), macrophage inflammatory protein 1alpha (MIP-1alpha), and MIP-1beta to CCR5-expressing cells at nanomolar concentrations. TAK-652 could also suppress the binding of monocyte chemotactic protein 1 (MCP-1) to CCR2b-expressing cells. However, its inhibitory effect on ligand binding to other chemokine receptors was limited. TAK-652 was active against CCR5-using (R5) HIV-1 but totally inactive against CXCR4-using (X4) HIV-1. The compound was active against R5 HIV-1 clinical isolates containing reverse transcriptase and protease inhibitor-resistant mutations, with a mean 50% effective concentration (EC50) and EC90 of 0.061 and 0.25 nM, respectively. In addition, recombinant R5 viruses carrying different subtype (A to G) envelope proteins were equally susceptible to TAK-652. A single oral administration of TAK-652 up to 100 mg was safe and well tolerated in humans. The compound displayed favorable pharmacokinetics, and its plasma concentration was 7.2 ng/ml (9.1 nM) even 24 h after the administration of 25 mg. Thus, TAK-652 is a promising candidate as a novel entry inhibitor of HIV-1.

A new approach to the synthesis of 4'-carbon-substituted nucleosides: development of a highly active anti-HIV agent 2', 3'-didehydro-3'-deoxy-4'-ethynylthymidine

Oxidation of 3'-O-TBDMS-4',5-unsaturated thymidine 3 with dimethyldioxirane (DMDO) allowed the isolation of the epoxide 4. Upon reacting with organosilicon reagents in the presence of SnCl4, 4 underwent stereoselective ring opening to give 4'-alpha-allyl (6), 4'-alpha-(2-bromoallyl) (7), 4'-alpha-(cyclopenten-3-yl) (8), and 4'-alpha-cyano (9) derivatives of thymidine. Reactions of the 3'-epimer 12 with organoaluminum reagents gave 4'-alpha-methyl (13), 4'-alpha-vinyl (14), and 4'-alpha-ethynyl (15) analogues. Compounds 13-15 were transformed into corresponding 2',3'-didehydro-3'-deoxy derivatives. Evaluation of their ability to inhibit the replication of HIV in cell culture showed that 4'-ethynyl-d4T (19) is more potent and less toxic than the parent compound d4T.

HIV-1-infected macrophages induce astrogliosis by SDF-1alpha and matrix metalloproteinases

Brain macrophages/microglia and astrocytes are known to be involved in the pathogenesis of HIV-1-associated dementia (HAD). To clarify their interaction and contribution to the pathogenesis, HIV-1-infected or uninfected macrophages were used as a model of brain macrophages/microglia, and their effects on human astrocytes in vitro were examined. The culture supernatants of HIV-1-infected or uninfected macrophages induced significant astrocyte proliferation, which was annihilated with a neutralizing antibody to stromal cell-derived factor (SDF)-1alpha or a matrix metalloproteinase (MMP) inhibitor. In these astrocytes, CXCR4, MMP, and tissue inhibitors of matrix metalloproteinase mRNA expression and SDF-1alpha production were significantly up-regulated. The supernatants of infected macrophages were always more effective than those of uninfected cells. Moreover, the enhanced production of SDF-1alpha was suppressed by the MMP inhibitor. These results indicate that the activated and HIV-1-infected macrophages can indirectly induce astrocyte proliferation through up-regulating SDF-1alpha and MMP production, which implies a mechanism of astrogliosis in HAD.

4'-Ethynylstavudine (4'-Ed4T) has potent anti-HIV-1 activity with reduced toxicity and shows a unique activity profile against drug-resistant mutants

A nucleoside analogue 4'-ethynylstavudine (4'-Ed4T) was recently synthesized during chemical studies directed towards the development of a new route to 4'-carbon-substituted nucleosides. This compound was found to be more anti-HIV-1 active than the parent compound stavudine (d4T) and much less toxic to various cells and also to mitochondrial DNA synthesis. It became apparent that 4'-Ed4T is a better substrate for human thymidine kinase than d4T, and very much more resistant to catabolism by thymidine phosphorylase. The study of 4'-Ed4T against various drug-resistant HIV-1 mutants has disclosed its unique activity profile.

The role of breast cancer resistance protein (BCRP/ABCG2) in cellular resistance to HIV-1 nucleoside reverse transcriptase inhibitors

Treatment of HIV-1-infected patients with anti-retroviral agents is not always successful due to the emergence of resistant HIV-1 mutants with reduced susceptibility to the agents. However, factors other than viral mutation may also contribute to treatment failure. It has been demonstrated that the ATP-binding cassette (ABC) transporter P-glycoprotein (P-gp/ABCB1) is a key determinant of oral bioavailability of HIV-1 protease inhibitors and their penetration of the central nervous system. More recently, we have found that the expression of breast cancer resistance protein (BCRP/ABCG2) in a CD4+ T-cell line confers cellular resistance to nucleoside reverse transcriptase inhibitors (NRTIs). The anti-HIV-1 activity of the NRTI zidovudine (AZT) was significantly diminished through the reduction of its metabolite levels in MT-4 cells which express high levels of BCRP. Moreover, the BCRP-specific inhibitor fumitremorgin C could completely restore the cytotoxicity of AZT and intracellular levels of its metabolites in BCRP-expressing cells. Thus, BCRP is considered to be a cellular factor that modulates the anti-HIV-1 activity of NRTIs.

[Advances in antiviral chemotherapy]

Establishment of selective antiviral chemotherapy has achieved dramatic improvement of the prognosis of several viral infections. It has been considered for a long time that, unlike bacterial infections, viral diseases cannot be successfully treated with chemotherapeutic agents, since viral replication mostly depends on the host-cellular machinery. In fact, some compounds were reported to inhibit viral replication even in the 1950s and 1960s, yet they were also quite toxic to the host cells. The first antiviral compound that strongly inhibits viral replication without affecting the uninfected cells is the anti-herpes agent acyclovir (ACV), which was discovered in the 1970s. Furthermore, in the 1980s, the world-wide epidemic of AIDS caused by human immunodeficiency virus type 1 (HIV-1) infection has dramatically accelerated the development of new antiviral agents. At present, most of the effective antivirals are targeted at virus-specific enzymes, such as ACV for herpes virus thymidine kinase, zidovudine for HIV-1 reverse transcriptase, squinavir for HIV-1 protease, and oseltamivir for neuraminidase of influenza virus. These agents can be administered systemically without serious side effects. However, several drawbacks, including delayed toxicity and drug-resistance, are associated with long-term treatment with several antiviral agents mostly in highly active antiretroviral therapy for HIV-1 infection. Thus, it seems still mandatory to continue the search for more effective and less toxic compounds against various viral infections.

AIDS vaccine: Intranasal immunization using inactivated HIV-1-capturing core-corona type polymeric nanospheres

Polymeric nanospheres have been widely used in biomedical applications, such as drug, gene and vaccine delivery systems. Nanospheres with entrapped antigens have recently been shown to possess significant potential as vaccine delivery systems and adjuvants. We previously reported that concanavalin A-immobilized polystyrene nanospheres (Con A-NS) could efficiently capture HIV-1 particles and intranasal immunization with inactivated HIV-1-capturing nanospheres (HIV-NS) induced vaginal anti-HIV-1 IgA antibody responses in mice. In addition, vaginal washes from intranasally immunized mice were capable of neutralizing HIV-1. Moreover, simian/human immunodeficiency virus KU-2-capturing nanospheres (SHIV-NS) immunized macaques exhibited partial protection when vaginally and systemically challenged with pathogenic viruses. HIV-NS is suggested to be particularly suitable to enhance antigen delivery to dendritic cells (DCs). In this study, we investigated the mucosal antibody response in mice after the intravaginal or intranasal immunization in detail with using different sized (360, 660, 940 and 1230 nm) HIV-NS. The amount of immobilized Con A to NS was dependent on the surface area of the particle. Moreover, Con A-NS with different sizes could equally capture inactivated HIV-1. Intravaginal or intranasal immunization by HIV-NS with diameters ranging 360 to 1230 nm significantly induced vaginal antibody responses. However, significant differences on vaginal anti-HIV-1 gp120 IgA and IgG antibodies were not found after intravaginal or intranasal immunization with different sized HIV-NS. These results suggest that HIV-NS provides an efficient vaccine delivery system for the induction of a mucosal immune response and the development of a mucosal vaccine.

Large-scale search of single nucleotide polymorphisms for hepatocellular carcinoma susceptibility genes in patients with hepatitis C

Hepatitis C virus (HCV) infection is a major risk factor for developing hepatocellular carcinoma (HCC). The host genetic factors that are involved in the development of HCC in patients with HCV infection remain to be investigated. To search for single nucleotide polymorphisms (SNPs) in HCC susceptibility genes, 393 SNPs in 171 candidate genes were examined in 188 Japanese patients with chronic HCV infection, including 77 patients with HCC. HCC-related SNPs were then examined in another 188 patients (including 93 patients with HCC) with chronic HCV infection. Haplotype analyses of HCC-related genes were performed in a total of 376 patients. Of the 393 SNPs, 31 SNPs in 29 genes were significantly associated with HCC based on an initial screening (P < .05). Of these 31 SNPs, 3 SNPs of 3 genes (SCYB14, GFRA1, and CRHR2) were significantly associated with HCC in a secondary screening. Haplotype analyses of these 3 genes identified 2 haplotype blocks associated with HCC. In conclusion, these SNPs and haplotypes located in the SCBY14, CRHR2, and GFRA1 genes will be used as markers to identify a subgroup of Japanese patients with chronic HCV infection who are at high risk of developing HCC.

Anti-human immunodeficiency virus type 1 activity and resistance profile of 2',3'-didehydro-3'-deoxy-4'-ethynylthymidine in vitro

2',3'-Didehydro-3'-deoxy-4'-ethynylthymidine (4'-Ed4T) has been identified as a novel nucleoside analog with potent and selective anti-human immunodeficiency virus type 1 (HIV-1) activity and weak cytotoxicity in cell cultures. 4'-Ed4T proved to be 5- to 10-fold more active than its structurally related compound, stavudine (d4T). However, the drug resistance profile of 4'-Ed4T was different from those of d4T and other existing HIV-1 nucleoside reverse transcriptase inhibitors (NRTIs). Approximately 6- to 11-fold decreases in susceptibility to 4'-Ed4T were observed for HIV-1 carrying NRTI-associated mutations (D67N, K70R, T215F, and K219Q) or the lamivudine (3TC)-resistant mutation M184V. In contrast, the susceptibility of the virus carrying the K65R mutation or the multidrug-resistant mutation with the Q151M complex (A62V, V75I, F77L, F116Y, and Q151M) was not altered. Furthermore, the activity of 4'-Ed4T appeared to be enhanced in the presence of K103N, a major nonnucleoside reverse transcriptase inhibitor-resistant mutation. Although 4'-Ed4T was 4.5- to 17.5-fold less active against multidrug-resistant clinical isolates than against a reference strain isolated from a treatment-naïve patient, it was still inhibitory to these isolates at low concentrations. Analysis of 4'-Ed4T-resistant HIV-1 obtained through in vitro selection revealed that the virus was also resistant to 3TC and had two amino acid mutations (P119S and T165A) in addition to the M184V mutation. Since 4'-Ed4T has increased anti-HIV-1 activity, decreased cytotoxicity, and a different resistance profile, it should be considered for further development as a new member of NRTIs.

Highly potent inhibition of human immunodeficiency virus type 1 replication by TAK-220, an orally bioavailable small-molecule CCR5 antagonist

TAK-220 is a member of a novel class of chemokine receptor antagonists and is highly specific to CCR5, as determined by receptor binding and calcium mobilization assays. The compound selectively inhibited coreceptor-mediated entry of human immunodeficiency virus type 1 (HIV-1) into host cells and HIV-1 infection mediated by CCR5. TAK-220 inhibited the replication of six CCR5-using (R5) HIV-1 clinical isolates in peripheral blood mononuclear cells (PBMCs) with a mean 90% effective concentration of 13 nM. The anti-HIV-1 activity of TAK-220 was not affected by addition of high concentrations of human serum. It equally inhibited R5 HIV-1 replication in PBMCs obtained from eight different donors, irrespective of the levels of viral production. Furthermore, the anti-HIV-1 activity of TAK-220 was found to be subtype independent. TAK-220 did not induce CCR5 internalization but blocked the binding of two monoclonal antibodies that recognize the second extracellular loop of CCR5 in CCR5-expressing cells. These results suggest that TAK-220 selectively inhibits R5 HIV-1 replication by interfering with coreceptor-mediated entry of the virus into host cells. At a dose of 5 mg/kg of body weight, TAK-220 showed oral bioavailabilities of 9.5 and 28.9% in rats and monkeys, respectively. Thus, TAK-220 is a promising candidate for the treatment of HIV-1 infection.

Experimental studies on excitation functions of the proton-induced activation reactions on yttrium

Proton-induced activation cross-sections were measured for the (89)Y(p,x)(89,88,86)Zr, (89)Y(p,x)(88,87,87 m,86)Y, (89)Y(p,x)(85,83,82)Sr and (89)Y(p,x)(84,83)Rb reactions by a stacked foil technique in the energy range 15-80 MeV which was covered by two separate measurements for 15-50 and 32-80 MeV energy range with 50 and 80 MeV incident protons. The differences between the results of two irradiations were found within 6% in the overlapping energy regions. The production yields for the long-lived products like (88)Zr, and (88)Y are significantly larger than that of (nat)Mo+p, (nat)Nb+p and (nat)Zr+p processes. The productions of the medical isotopes, (85)Sr and (83)Sr are also effective by Y+p process using an 80 MeV beam. Thick target integral yields were also deduced using the measured cross-sections. The (87)Y, (88)Y, (88)Zr and (89)Zr radionuclides have suitable yields and decay characteristics important for thin-layer activation (TLA) analysis.

Induction of dendritic cell-mediated immune responses against HIV-1 by antigen-capturing nanospheres in mice

Prophylactic vaccines, designed to elicit potent humoral and cellular immune responses to human immunodeficiency virus type 1 (HIV-1) antigens in mucosa, are the important approach to the protection of individuals against HIV-1 infection, since HIV-1 transmission is largely a result of sexual contact. In this study, a novel strategy has been developed to induce HIV-1-specific immune responses, which involves inactivated HIV-1-caputring concanavalin A (Con A)-immobilized nanospheres (HIV-NS) and their interaction with bone marrow (BM)-derived dendritic cells. HIV-NS were taken up by dendritic cells via cytoskeleton-dependent but mannose-binding site-independent phagocytosis. Serial stimulations to unprimed T-cells with HIV-1 gp120-capturing NS-pulsed dendritic cells could induce antigen-specific T-cell response. Intranasal administration of fluorescein isothiocyanate-labeled nanospheres (NS) in mice proved that the particles were taken up into pulmonary dendritic cells. Analysis of mice receiving intranasal immunizations with HIV-NS revealed that the mice efficiently induced the antibodies against HIV-1 in the genital tract and specific cytotoxic T-cells in the spleen. These results suggest that the use of HIV-1-NS may provide a novel and promising approach for the induction of humoral and cellular immune responses to HIV-1.

Studies of non-nucleoside HIV-1 reverse transcriptase inhibitors. Part 2: synthesis and structure-activity relationships of 2-cyano and 2-hydroxy thiazolidenebenzenesulfonamide derivatives

In a previous study, we described the structure-activity relationships (SARs) for a series of thiazolidenebenzenesulfonamide derivatives. These compounds were found to be highly potent inhibitors of the wild type (WT) and Y181C mutant reverse transcriptases (RTs) and modest inhibitors of K103N RT. These molecules are thus considered to be a novel class of non-nucleoside HIV-1 RT inhibitors (NNRTIs). In this paper, we have examined the effects of substituents on both the thiazolidene and benzenesulfonamide moieties. Introduction of a 2-cyanophenyl ring into these moieties significantly enhanced anti-HIV-1 activity, whereas a 2-hydroxyphenyl group endowed potent activity against RTs, including K103N and Y181C mutants. Among the series of molecules examined, 10l and 18b (YM-228855), combinations of 2-cyanophenyl and 4-methyl-5-isopropylthiazole moieties, showed extremely potent anti-HIV-1 activity. The EC50 values of 101 and 18b were 0.0017 and 0.0018 microM, respectively. These values were lower than that of efavirenz (3). Compound 11g (YM-215389), a combination of 2-hydroxyphenyl and 4-chloro-5-isopropylthiazole moieties, proved to be the most active against both K103N and Y181C RTs with IC50 values of 0.043 and 0.013 microM, respectively.

Age associated axonal features in HNPP with 17p11.2 deletion in Japan

OBJECTIVE

To clarify age related changes in the clinicopathological features of hereditary neuropathy with liability to pressure palsy (HNPP) in Japanese patients with deletion of 17p11.2, particularly concerning axonal abnormalities.

METHODS

Forty eight proband patients from 48 HNPP families were assessed as to clinical, electrophysiological, and histopathological features, including age associated changes beyond those in controls.

RESULTS

Motor conduction studies showed age associated deterioration of compound muscle action potentials in nerves vulnerable to repetitive compression (median, ulnar, and peroneal nerves), but not in others such as the tibial nerve. Sensory conduction studies revealed more profound reduction of action potentials than motor studies with little age related change. Large myelinated fibre loss was seen in the sural nerve irrespective of age at examination.

CONCLUSIONS

Irreversible axonal damage may occur at entrapment sites in motor nerves in HNPP patients, progressing with aging. Sensory nerves may show more profound axonal abnormality, but without age association. The electrophysiological features of HNPP are presumed to be a mixture of abnormalities occurring from early in life and acquired features caused by repetitive insults at entrapment sites. Unlike Charcot-Marie-Tooth disease type 1A, age associated axonal damage may not occur unless the nerves are subjected to compression.

Synthesis of (+/-)-4'-ethynyl and 4'-cyano carbocyclic analogues of stavudine (d4T)

The synthesis of (+/-)-4'-ethynyl (8) and 4'-cyano (9) carbocyclic analogues of the anti-HIV agent stavudine (5, d4T) is reported. The carbocyclic unit (16) was constructed from readily available beta-keto ester 10. The ethynyl or cyano group of 8 and 9 were prepared, after the introduction of thymine base to 16, by manipulation of the ester function. Evaluation of the anti-HIV activity of 8 and 9 was also carried out.

Orally active CCR5 antagonists as anti-HIV-1 agents. Part 3: Synthesis and biological activities of 1-benzazepine derivatives containing a sulfoxide moiety

In order to develop orally active CCR5 antagonists, 1-propyl- or 1-isobutyl-1-benzazepine derivatives containing a sulfoxide moiety have been designed, synthesized, and evaluated for their biological activities. Sulfoxide compounds containing a 2-pyridyl group were first investigated, which led to discovering that the presence of a methylene group between the sulfoxide moiety and 2-pyridyl group was necessary for increased inhibitory activity in a binding assay. After further chemical modification, it was found that replacement of the pyridyl group with an imidazolyl or 1,2,4-triazolyl group enhanced activity in the binding assay and that S-sulfoxide compounds were more active than R-isomers. Particularly, compounds (S)-4r, (S)-4s, and (S)-4w exhibited highly potent CCR5 antagonistic activities (IC50=1.9, 1.7, 1.6 nM, respectively) and inhibitory effects (IC50=1.0, 2.8, 7.7 nM, respectively) in the HIV-1 envelope mediated membrane fusion assay, together with good pharmacokinetic properties in rats. In addition, we established the synthesis of (S)-4r and (S)-4w by asymmetric oxidation with titanium-(S)-(-)-1,1'-bi-2-naphthol complex.

Clinical and electrophysiologic correlates of IVIg responsiveness in CIDP

To identify clinical and electrophysiologic features related to IV immunoglobulin (IVIg) responsiveness in chronic inflammatory demyelinating polyneuropathy (CIDP), the authors conducted a multicenter study on 312 patients with CIDP (199 responders and 113 nonresponders). Muscle atrophy and decreased compound muscle action potential were pronounced in nonresponders of IVIg. Male gender, longer disease duration, and slow progression of symptoms were also associated with IVIg unresponsiveness. Features suggesting axonal dysfunction in peripheral nerves indicated IVIg unresponsiveness in CIDP.

Colorimetric lactate dehydrogenase (LDH) assay for evaluation of antiviral activity against bovine viral diarrhoea virus (BVDV) in vitro

A rapid and sensitive screening assay has been established for in vitro evaluation of antiviral compounds against bovine viral diarrhoea virus (BVDV), which is widely used as a surrogate for hepatitis C virus (HCV). The procedure is based on photospectrometrical assessment for the viability of virus-infected cells via extracellular leakage of lactic dehydrogenase (LDH). The level of LDH in culture supernatants of BVDV-infected Madin-Darby bovine kidney (MDBK) cells was significantly higher than those of mock-infected MDBK cells. Under optimized assay conditions, the LDH level was found to correlate well with the degree of viral replication. When the 50% effective concentrations (EC50s) of ribavirin, cyclosporine A and human interferon-alpha for BVDV replication were determined by the established LDH method and compared with those obtained by a conventional tetrazolium colorimetric (MTT) method, there was a complete correlation in EC50s between the two methods. Furthermore, a much higher ratio of background activity (noise) to sample activity (signal) could be achieved with the LDH method than with the MTT method, indicating that the present LDH assay permits a sensitive, rapid and reliable screening of compounds for their anti-BVDV activity and may be useful for the discovery of novel anti-HCV agents.

Experimental studies on excitation functions of the proton-induced activation reactions on silver

Excitation functions were measured for the production of 106m,105Ag, 103,101,100Pd, 105,102,101m,100,99Rh and 97Ru via proton-induced activation reactions on natural silver using a stacked foil technique in the energy range 11-80 MeV. The residual activity measurements were carried out nondestructively by the high-resolution HPGe gamma-ray spectroscopy. Thick target integral yields were deduced using the measured cross-sections from the respective threshold energies of the investigated reactions up to 80 MeV. The present work gives new results for the investigated radionuclides. The data in MENDL-2P deduced with the theoretical model code ALICE-IPPE are consistent in shape with the measured values, but show disagreement in magnitude.

Association of the ABCA1 gene polymorphisms with type 2 DM in a Japanese population

To examine the association of the ATP-binding cassette transporter 1 (ABCA1) gene with type 2 diabetes (DM), we studied genetic polymorphisms of the ABCA1 gene including its linkage disequilibrium (LD) and haplotype analyses using a Japanese population. A sample set (DM:72, IGT:75, and NGT:227) was genotyped with 34 SNPs distributed from the promoter region to the last exon of the ABCA1 gene. LD between SNPs was assessed in pairwise manner. Among 13 LD blocks constructed, an LD block at the 5'-region showed a significant difference in the haplotype distribution between the study groups (NGT vs. IGT + DM: overall p = 0.0180; NGT vs. DM: 0.0001). Fisher's exact probability test (NGT vs. DM) showed a significant association of the haplotype 2 of the LD block (p = 0.0001), with an odds ratio (OR) of 2.53 (95%CI:1.62-4.12). Diplotype analysis also showed a significant association of the diplotypes with the haplotype 2 (OR:2.59, 95%CI:1.48-4.54, p = 0.0013).

TRAIL-Transduced Dendritic Cells Protect Mice from Acute Graft-versus-Host Disease and Leukemia Relapse

TRAIL preferentially induces apoptotic cell death in a wide variety of transformed cells, whereas it induces no apoptosis, but inhibits activation of Ag-specific T cells via blockade of cell cycle progression. Although accumulating results suggest that TRAIL is involved in the maintenance of immunological homeostasis under steady state conditions as well as in the initiation and progression of immunopathologies, the potential regulatory effect of TRAIL on immune responses and its therapeutic potential in immunological diseases remains unclear. We report in this study the potential usefulness of TRAIL-transduced dendritic cells (DCs) for the treatment of lethal acute graft-vs-host disease (GVHD) and leukemia relapse. DCs genetically modified to express TRAIL showed potent cytotoxicity against both alloreactive T cells and leukemic cells through the induction of apoptosis. In addition, treatment with genetically modified DCs expressing TRAIL of allogeneic BM transplants recipients with leukemia was effective for protection against acute GVHD and leukemia relapse. Thus, gene transfer of TRAIL to DCs is a novel modality for the treatment of acute GVHD and leukemia relapse by selective targeting of pathogenic T cells and leukemic cells.

Synthesis and antiviral activities of 1'-carbon-substituted 4'-thiothymidines

4-Thiofuranoid glycals substituted at the 1-position with methyl (5), (t-butyldimethylsilyloxy)methyl (7), and acetoxymethyl (8) groups were prepared from the 3,5-O-(1,1,3,3-tetraisopropyldisiloxane-1,3-diyl) (TIPDS)-4-thiofuranoid glycal (3) by way of LDA-lithiation. N-Iodosuccimide-initiated electrophilic glycosidation between silylated thymine and these 1-carbon-substituted 4-thioglycals gave the respective beta-anomers (9, 10, and 13) stereoselectively. Tin radical-mediated removal of the 2'-iodine atom from these products provided the corresponding 1'-branched 4'-thiothymidine derivatives (11, 12, and 14) in good yields. The 1'-hydroxymethyl derivative (15) served as a precursor for the preparation of the formyl (16), cyanoethenyl (17), and cyano (19) derivatives. Among the deprotected 1'-branched 4'-thiothymidines (20-25), the 1'-methyl analogue 20 showed the most potent anti-HSV-1 activity, but it was much less active than the parent compound 4'-thiothymidine.

Inhibition of bovine viral diarrhea virus (BVDV) by mizoribine: synergistic effect of combination with interferon-alpha

Bovine viral diarrhea virus (BVDV) is a well-characterized member of the Flaviviridae family. BVDV may be a surrogate model for human hepatitis C virus (HCV), since HCV does not replicate efficiently in cell cultures and animals. Mizoribine, a nucleoside analog clinically used as an immunosuppressant, was found to be active against the replication of BVDV in cell culture. We further investigated the combination of mizoribine and interferon (IFN)-alpha for antiviral activity and found that the combination synergistically inhibited BVDV replication in bovine kidney cells, as monitored by the inhibition of virus-induced cytopathicity. The combination of ribavirin and IFN-alpha was also synergistic in inhibiting BVDV replication. Treatment of infected cells with a combination of mizoribine and IFN-alpha at the concentrations, at which the respective compounds proved to be inactive, markedly reduced viral infectivity in culture supernatants. These results indicate that mizoribine in combination with IFN-alpha may have potential for the treatment of HCV infection.

Synthesis and anti-HIV activity of 4'-cyano-2',3'-didehydro-3'-deoxythymidine

A new anti-HIV agent 4'-cyano-2',3'-didehydro-3'-deoxythymidine (9) was synthesized by allylic substitution of the 3',4'-unsaturated nucleoside 14, having a leaving group at the 2'-position, with cyanotrimethylsilane in the presence of SnCl4. Evaluation of the anti-HIV activity of 9 showed that this compound is much less potent than the recently reported 2',3'-didehydro-3'-deoxy-4'-(ethynyl)thymidine (1).

CCR5 antagonists as anti-HIV-1 agents. Part 3: Synthesis and biological evaluation of piperidine-4-carboxamide derivatives

Replacement of the 5-oxopyrrolidin-3-yl fragment in the previously reported lead structure with a 1-acetylpiperidin-4-yl group led to the discovery of a novel series of potent CCR5 antagonists. Introduction of small hydrophobic substituents on the central phenyl ring increased the binding affinity, providing low to sub-nanomolar CCR5 antagonists. The selected compound 11f showed excellent antiviral activity against CCR5-using HIV-1 replication in human peripheral blood mononuclear cells (EC50=0.59 nM) and an acceptable pharmacokinetic profile in dogs.

Activation cross-sections of long-lived products of proton-induced nuclear reactions on zinc

In the frame of a systematic study of excitation functions induced by medium energy protons, the activation cross-sections on natural zinc were investigated for different applications. Excitation functions for production of 66,67Ga, 62,65,69mZn, 64Cu, 57Ni, 55,56,57,58Co and 52,54Mn radioisotopes were measured by the stacked foil technique in the energy range of 26-67 MeV. Results were compared with the earlier reported experimental data and theoretical calculations based on the ALICE-IPPE code. Experimental data are presented for the first time for most of the products in the investigated energy range. Applications of the measured data for validating the cross-sections on highly enriched isotopic Zn targets and for thin layer activation method are discussed.

Differential absorbed dose distributions in lineal energy for neutrons and gamma rays at the mono-energetic neutron calibration facility

Absorbed dose distributions in lineal energy for neutrons and gamma rays of mono-energetic neutron sources from 140 keV to 15 MeV were measured in the Fast Neutron Laboratory at Tohoku University. By using both a tissue-equivalent plastic walled counter and a graphite-walled low-pressure proportional counter, absorbed dose distributions in lineal energy for neutrons were obtained separately from those for gamma rays. This method needs no knowledge of energy spectra and dose distributions for gamma rays. The gamma-ray contribution in this neutron calibration field >1 MeV neutron was <3%, while for <550 keV it was >40%. The measured neutron absolute absorbed doses per unit neutron fluence agreed with the LA150 evaluated kerma factors. By using this method, absorbed dose distributions in lineal energy for neutrons and gamma rays in an unknown neutron field can be obtained separately.

Studies of nonnucleoside HIV-1 reverse transcriptase inhibitors. Part 1: Design and synthesis of thiazolidenebenzenesulfonamides

A random high-throughput screening (HTS) program to discover novel nonnucleoside reverse transcriptase inhibitors (NNRTIs) has been carried out with MT-4 cells against a nevirapine-resistant virus, HIV-1(IIIB-R). The primary hit, a thiazolidenebenzenesulfonamide derivative, possessed good activity. A systematic modification program examining various substituents at the 3-, 4-, and 5-positions on the thiazole ring afforded compounds with enhanced anti-HIV-1 and reverse transcriptase (RT) inhibitory activities. These results confirm the important role of the substituents at these positions and the thiazolidenebenzenesulfonamide motif as a valuable lead series for the next generation NNRTIs.

Induction of cellular resistance to nucleoside reverse transcriptase inhibitors by the wild-type breast cancer resistance protein

Breast cancer resistance protein (BCRP/ABCG2) is a novel member of ATP-binding cassette transporters, which induce multidrug resistance in cancer cells. We previously reported that a high level of BCRP expression in CD4(+) T cells conferred cellular resistance to nucleoside reverse transcriptase inhibitors (NRTIs) of human immunodeficiency virus type 1 (HIV-1). However, this BCRP was found to have a mutation of Arg to Met at position 482 (BCRP(R482M)). The present study demonstrated that the wild-type BCRP (BCRP(WT)) also conferred cellular resistance to NRTIs. MT-4 cells (a CD4(+) T-cell line) highly expressing BCRP(WT) (MT-4/BCRP) were generated and the expression of BCRP(WT) was confirmed by genotypic and phenotypic analyses. Compared to the parental MT-4 cells, MT-4/BCRP cells displayed resistance to zidovudine (AZT) in terms of antiviral activity as well as drug cytotoxicity. In addition, other NRTIs were also less inhibitory to HIV-1 replication in MT-4/BCRP cells than in MT-4 cells. Significant reduction of intracellular AZT accumulation was observed in MT-4/BCRP cells. An analysis for intracellular metabolism of AZT suggested that the resistance was attributed to the increased efflux of AZT and its metabolites in MT-4/BCRP cells. Furthermore, the BCRP-specific inhibitor fumitremorgin C completely restored the reduction of AZT in MT-4/BCRP cells. These results indicate that, like BCRP(R482M), BCRP(WT) also plays an important role in cellular resistance to NRTIs.

Benchmark experiments for cyclotron-based neutron source for BNCT

In the previous study, we found the feasibility of a cyclotron-based BNCT using the Ta(p,n) neutrons at 90 degrees bombarded by 50 MeV protons, and the iron, AlF(3), Al and (6)LiF moderators by simulations using the MCNPX code. In order to validate the simulations to realize the cyclotron-based BNCT, we measured the epithermal neutron energy spectrum passing through the moderators with our new spectrometer consisting of a (3)He gas counter covered with a silicon rubber loaded with (nat)B and polyethylene moderator and the depth distribution of the reaction rates of (197)Au(n,gamma)(198)Au in an acrylic phantom set behind the rear surface of the moderators. The measured results were compared with the calculations using the MCNPX code. We obtained the good agreement between the calculations and measurements within approximately 10% for the neutron energy spectra and within approximately 20% for the depth distribution of the reaction rates of (197)Au(n,gamma)(198)Au in the phantom. The comparison clarified a good accuracy of the calculation of the neutron energy spectrum passing through the moderator and the thermalization in a phantom. These experimental results will be a good benchmark data to evaluate the accuracy of the calculation code.

[Recent progress in anti-HIM-1 research]

Establishment of highly active antiretroviral therapy (HAART) has brought about dramatic improvement of the prognosis of HIV-1 infection. On the other hand, several drawbacks associated with long-term HARRT have been demonstrated. Among them, emergence of drug-resistant viruses is a serious problem; therefore compounds with novel mechanisms of action have been investigated to overcome the problem. Novel reverse transcriptase inhibitors (RTIs) and protease inhibitors (PIs) recently approved for clinical use are effective against existing resistant strains by once daily administration. In addition, the virus entry (fusion) inhibitor has also been licensed. Since this compound targets a molecule other than reverse transcriptase and protease for inhibition of HIV-1 replication, it is active against HIV-1 highly resistant to RTIs and PIs. Furthermore, clinical trials with CCR 5 (coreceptor of HIV-1) antagonists are in progress, and inhibitors of integrase, HIV-1 gene expression, and virion assembly have been identified.

Synthesis of Benzodithiol-2-yl-Substituted Nucleoside Derivatives as Lead Compounds Having Anti-Bovine Viral Diarrhea Virus Activity

Nucleoside derivatives having a benzodithiol-2-yl (BDT) group were synthesized and examined for their anti-bovine viral diarrhea virus (BVDV) activities. Other substituents structurally similar to the BDT group such as 1,3-benzodioxol-2-yl, benzimidazol-2-yl and 1-oxo-benzodithiol-2-yl groups were not effective as the pharmacophore. The anti-BVDV assay revealed that 2'-O-BDT-guanosine and 2'-O-BDT-inosine had the strongest anti-BVDV activity among the nucleoside derivatives synthesized in this study. Since BVDV has been recognized as a surrogate for human hepatitis C virus (HCV), the BDT-modified nucleosides might become a new class of lead compounds to find nucleoside-type anti-HCV agents such as ribavirin.

CCR5 antagonists as anti-HIV-1 agents. 1. Synthesis and biological evaluation of 5-oxopyrrolidine-3-carboxamide derivatives

A novel lead compound, N-(3-[4-(4-fluorobenzoyl)piperidin-1-yl]propyl)-1-methyl-5-oxo-N-phenylpyrrolidine-3-carboxamide (1), was identified as a CCR5 antagonist by high-throughput screening using [(125)I]RANTES and CCR5-expressing CHO cells. The IC(50) value of 1 was 1.9 microM. In an effort to improve the binding affinity of 1, a series of 5-oxopyrrolidine-3-carboxamides was synthesized. Introduction of 3,4-dichloro substituents to the central phenyl ring (10i, IC(50)=0.057 microM; 11b, IC(50)=0.050 microM) or replacing the 1-methyl group of the 5-oxopyrrolidine moiety with a 1-benzyl group (12e, IC(50)=0.038 microM) was found to be effective for improving CCR5 affinity. Compound 10i, 11b, and 12e also inhibited CCR5-using HIV-1 envelope-mediated membrane fusion with IC(50) values of 0.44, 0.19, and 0.49 microM, respectively.

Asymmetric synthesis of novel thioiso dideoxynucleosides with exocyclic methylene as potential antiviral agents

Novel thioiso pyrimidine and purine nucleosides substituted with exocyclic methylene have been synthesized, starting from D-xylose. The glycosyl donor 14 was synthesized from D-xylose, using cyclization of dimesylate 10 with sodium sulfide as a key step. Cyclization proceeded in pure S(N)2 reaction without going through S(N)1 reaction in the presence of an allylic functional group at low reaction temperature (0 degrees C) in polar solvent (DMF), affording compound 12 as a major product. At higher temperatures, S(N)2' product 11 was almost exclusively obtained as a major product. On the other hand, glycosylation of 14 with 6-chloropurine under Mitsunobu conditions afforded the desired S(N)2 product 26, while palladium-catalyzed glycosylation resulted in the sole formation of S(N)2' product 34.