Preparation and characterization of new challenge stocks of SIVmac32H J5 following rapid serial passage of virus in vivo.

BACKGROUND: A new challenge stock of the simian immunodeficiency virus SIVmacJ5 has been produced following passage in vivo. METHODS: SIVmacJ5 3/92 (J5M), was passaged serially through cynomolgus macaques (Macaca fascicularis) by intravenous inoculation of infected spleen cells isolated and prepared 14 days post-infection. Two challenge stocks, SIVmacJ5 S61MLN and SIVmacJ5 S62spl, were prepared by culture of lymphoid tissue ex vivo. RESULTS: These virus stocks appeared better adapted for replication in M. fascicularis as demonstrated by a greater persistence of recoverable live virus from the periphery and increased pathology in lymphoid tissues 20 weeks post-challenge as detected by immunohistochemistry. Sequence analysis of the envelope gene from these stocks did not identify marked diversification of sequence as a result of this procedure. CONCLUSIONS: These stocks display more robust peripheral persistence and tissue pathology in cynomolgus macaques and should prove valuable analysing recombinant vaccines based upon SIVmacJ5 transgenes.

Bioactividad de los extractos y aislamiento de los lignanos de las semillas de Centaurea dealbata / Bioactivity of the extracts and the isolation of lignans from the seeds of Centaurea dealbata

La Centaurea dealbata Willd. (familia: Asteraceae) pertenece al género Centaurea, que comprende unas 500 especies. Para evaluar la actividad antioxidante y la toxicidad general de los extractos de n-hexano, diclorometano (DCM) y metanol (MeOH) de las semillas de C. dealbata se han utilizado, respectivamente, el ensayo DPPH y el ensayo de letalidad de gambas en salmuera. Tanto el extracto de DCM como el de MeOH presentaron niveles signifi cativos de actividad antioxidante, con valores de RC50 de 6,8 x 10-2 y 4,7 x 10-2 mg/mL, respectivamente. Ninguno de los extractos presentó una toxicidad general signifi cativa (LD50 = >1000 mg/mL). Se observó que los tres principales componentes bioactivos del extracto de MeOH fueron los lignanos arctigenina, arctiina y matairesinosida. Las estructuras de estos lignanos se dilucidaron mediante análisis espectroscópicos exhaustivos y comparación directa con los datos respectivos publicados. Éste es el primer informe sobre la ocurrencia de arctiina y matairesinol en C. dealbata. También se presenta la distribución de estos lignanos dentro del género Centaurea

Centaurea dealbata Willd. (Family: Asteraceae) belongs to the big genus Centaurea that comprises ca. 500 species. The n-hexane, dichloromethane (DCM) and methanol (MeOH) extracts of the seeds of C. dealbata have been assessed for antioxidant activity and general toxicity using, respectively, the DPPH assay, and the brine shrimp lethality assay. Both the DCM and the MeOH extract showed signifi cant levels of antioxidant activities with an RC50 value 6.8 x 10-2 and 4.7 x 10-2 mg/mL, respectively. None of the extracts exhibited any signifi cant general toxicity (LD50 = >1000 mg/mL). Three major bioactive components of the MeOH extract were found to be the lignans, arctigenin, arctiin and matairesinoside. The structures of these lignans were elucidated by comprehensive spectroscopic analyses, and also by direct comparison with the respective published data. This is the fi rst report on the occurrence of arctiin and matairesionl in C. dealbata. The distribution of these lignans within the genus Centaurea has also been presented

Specific proliferative T cell responses and antibodies elicited by vaccination with simian immunodeficiency virus Nef do not confer protection against virus challenge.

The efficacy of immunizing with a combination of simian immunodeficiency virus (SIV) Nef vaccines was evaluated. Four vaccinates received three intradermal immunizations with recombinant vaccinia virus that expressed SIV Nef, followed by three intramuscular immunizations with rDNA also expressing SIV Nef. Finally, the four vaccinates received two subcutaneous boosts with recombinant SIV Nef protein. This immunization protocol elicited anti-Nef antibodies in all of the vaccinates as well as specific proliferative responses. However, specific cytotoxic T cell responses were not detected before virus challenge. All vaccinates were challenged intravenously with 10 MID(50) of SIVmacJ5 along with four controls. All eight subjects became infected after SIV challenge and there were no group-specific differences in virus load as measured by virus titration and vRNA analysis. The results of this study support indirectly the report from Gallimore and colleagues (Nat Med 1995;1:1667) suggesting that CD8(+) T lymphocyte responses are required for Nef-based vaccines to restrict SIV infection. If Nef-based vaccines are to be beneficial in controlling infection with immunodeficiency viruses, then it will be necessary to develop more effective immunization protocols that elicit potent CD8(+) cell responses reproducibly.

Hydrogen bonding in salicylsalicylic acid (salsalate) crystals.

An X-ray crystallographic study of the drug salsalicylic acid (salsalate) has been performed. Crystal formation of the drug is influenced by both inter- and intra-molecular hydrogen bonding. In addition an OH group in salsalate can occupy alternate ortho positions resulting in two hydrogen bonding motifs within a single crystal.