In vivo antiviral activity of ribavirin/alpha-cyclodextrin complex: evaluation on experimental measles virus encephalitis in mice.

Intracranial injection of the rodent adapted CAM/RB strain of measles virus (MV) induces encephalitis in CBA/ca mice. It has already been shown that cyclodextrins can be used as carriers to increase the antiviral activity of ribavirin (RBV) against MV in cellular model. In this study, the antiviral activity of a RBV/alpha-cyclodextrin complex has been evaluated in vivo using the above model. CBA/ca mice were treated by intraperitoneal injection of free ribavirin (40 mg/kg) or a RBV/alpha-cyclodextrin complex (molar ratio 1:3). After 21 days, intracerebral injection of CAM/RB resulted in 100% mortality in the mock group. In contrast, mortality rates of 80% and 40%, respectively, were observed in RBV and RBV/alpha-CD-treated mice (p<0.05 and p=0.06 for distilled water and RBV, respectively). The viral load of MV in the mouse brain was monitored daily by real-time PCR until day 6 after infection, to compare virus production in treated and non-treated mice. This data shows that RBV complexation with alpha-cyclodextrin can increase the antiviral activity of ribavirin in a measles virus encephalitis model in mice.

Evaluation by Q-RTPCR of the efficacy of ribavirin complexed with beta-cyclodextrin against measles virus in a mouse encephalitis model.

The objective of this work was to study the antiviral activity of ribavirin on measles encephalitis infection when using cyclodextrins as carriers. The use of cyclic oligosaccharides can promote the activity of many drugs and the benefit of the association of ribavirin with beta-cyclodextrin has already been demonstrated in vitro. Intracranial inoculation of the rodent adapted neurovirulent CAM/RB strain of measles virus induces encephalitis in CBA/ca mice. The antiviral activity of the complex ribavirin/beta-cyclodextrin at molar ratio 1:1 has been evaluated in vivo in the above encephalitis model. CBA/ca mice were treated with daily intraperitoneal injection of ribavirin (40 mg/kg) with or without beta-cyclodextrin. The viral load in the brain of mice was quantified by real-time Reverse transcription-Polymerase chain reaction. Treatment of mice by the complex ribavirin/beta-cyclodextrin (1:1) by intraperitoneal route decreases the viral load in the brain of 1.1 and 0.7 log(10) Eq copies x mL(-1) compared to distillated water and ribavirin treatment, respectively. At the same time, free ribavirin injection shows a negligible difference compared to treatment by distillated water.

Isolation of the provisionally named Desulfovibrio fairfieldensis from human periodontal pockets.

Sulfate-reducing bacteria have recently been associated with periodontitis and proposed to play a role in the pathogenesis of this chronic inflammatory process. Eight isolates of sulfate-reducing bacteria belonging to the genus Desulfovibrio were obtained from the periodontal pockets of five out of seven patients presenting with active periodontitis. A multiplex PCR was devised for their identification at the species level. All isolates were identified as Desulfovibrio fairfieldensis, a recently proposed new species. This finding reinforces the suggestion that Desulfovibrio fairfieldensis is a human bacterium that may present a pathogenic potential.

Analysis of tissue chimerism in nude mouse brain and abdominal xenograft models of human glioblastoma multiforme: what does it tell us about the models and about glioblastoma biology and therapy?

In situ hybridization coupled to immunohistochemistry for antigens of interest allows unequivocal identification of tumor cells from reactive stroma cells and normal adjacent structures in human glioblastoma multiforme grafts transplanted into nude mice. With this methodology, we have explored the development of glioblastoma multiforme solid grafts transplanted into nude mouse brains or flanks. The brain transplants closely resembled the human situation, particularly in relation to differentiation and growth patterns. The morphological features of peritumoral reactive gliosis were similar to those observed in humans. A mouse glial stroma within the main tumor masses was also demonstrated. Kinetic studies showed that the compartment of isolated tumor cells that infiltrated host brains and the reactive gliosis constituted two cycling cell populations. Despite VEGF protein expression by tumor cells and some reactive astrocytes, the abnormally permeable microvascular beds were not hyperplastic. The observation of a non-infiltrative pattern of growth when grafts were established in host flanks demonstrated that the organ-specific environment plays a determining role in the growth and invasive properties of glioblastoma. The phylogenetic distance between man and mouse and the recipient immunoincompetence should not impose serious limitations on the use of this model for studying malignant glioma biology and therapy in vivo.

Susceptibility of clinical strains of herpes simplex virus to three nucleoside analogues.

The susceptibility of clinical isolates of herpes simplex virus 1 (HSV1) (58 strains) and 2 (HSV2) (17 strains) from the Centre Hospitalier et Universitaire de Nancy to three nucleoside analogues was compared by the dye uptake method. As expected, all strains of HSV2 were resistant to brovavir or sorivudine. Aciclovir and penciclovir activities were comparable; 2 strains of HSV1 were resistant to these two compounds. Four strains isolated from immunocompromised patients gave different results with brovavir as compared to aciclovir; resistance to aciclovir (1 strain of HSV1) did not correlate with resistance to brovavir (3 strains of HSV1). Following up antiviral susceptibility is of interest for the detection of resistant strains in immunocompromised patients receiving prophylactic aciclovir.

Bacteremia caused by a strain of Desulfovibrio related to the provisionally named Desulfovibrio fairfieldensis.

Eight isolates of Desulfovibrio spp. have been obtained over 5 years from abdominal or brain abscesses or blood. Seven isolates were part of a mixed flora [corrected]. One strain was isolated in pure culture from the blood of a patient with peritonitis of appendicular origin. According to the 16S rRNA gene sequences, this strain was close to Desulfovibrio fairfieldensis. The present report describes the fourth isolate of this recently described species to be isolated in pure culture or as a predominant part of the flora and to be associated with infectious processes. Thus, D. fairfieldensis may possess a higher pathogenic potential than other Desulfovibrio species.

Value of enterobacterial repetitive intergenic consensus PCR for study of Pasteurella multocida strains isolated from mouths of dogs.

Fifty-six Pasteurella multocida strains (40 P. multocida subsp. septica and 16 P. multocida subsp. multocida strains) isolated from the mouths of 56 dogs among the 134 living in a French canine military training center (132e Groupe Cynophile de l'Armée de Terre, Suippes, France) were studied by use of enterobacterial repetitive intergenic consensus-PCR (ERIC-PCR) and restriction fragment length polymorphism (RFLP) techniques. Both techniques showed genomic heterogeneity of the strains studied. However, RFLP was more discriminatory than ERIC-PCR for differentiating P. multocida strains. All but three pairs of strains were discriminated by RFLP, suggesting a limited circulation of strains between these dogs living in proximity. Although ERIC-PCR is easier and faster to perform, it cannot be recommended for epidemiological studies of P. multocida strains.

Characterization of a soluble ferric reductase from Neisseria gonorrhoeae.

An NADH-dependent ferric reductase was identified in extracts of Neisseria gonorrhoeae. Enzyme activity was measured in an assay using ferrozine as the ferrous iron acceptor. Ferric reductase activity was enhanced by Mg2+ and flavine nucleotides. The enzyme reduced both citrate- and diphosphate-bound ferric iron as well as ferric hydroxide (Imferon). However, no activity was observed with either 30%-iron-saturated transferrin or with the gonococcal iron-binding protein, Fbp. The ferric reductase was found primarily within the cytoplasmic cell fraction. The soluble ferric reductase was purified 110-fold by ammonium sulfate precipitation, gel and anion-exchange chromatography. Results obtained following gel chromatography and SDS/polyacrylamide gel electrophoresis suggested that the enzyme had a molecular mass of about 25 kDa.

What can be expected from the cytologic examination of cervicovaginal smears for the diagnosis of Chlamydia trachomatis infections?

The value of Papanicolaou-stained smears for the diagnosis of chlamydial infections is still disputed. A comparative examination of smears from infected and uninfected women has allowed the proposal of a new scheme for the interpretation of the cytologic abnormalities associated with chlamydial infection. In particular, the appearances of metaplastic cells were classified, and two smear types were found to have the highest sensitivities and positive predictive values: smears in which the metaplastic cells had (1) intracytoplasmic vacuoles containing polymorphonuclear leukocytes or (2) numerous small intracytoplasmic vacuoles containing a central eosinophilic granule. The sensitivity of this method is low, however; cytology cannot replace bacteriologic identification for the diagnosis of chlamydial infections. Nevertheless, the examination of Papanicolaou-stained smears could be considered as a screening tool in low-risk populations; provided that all of the cytologic features were considered, presumptive diagnoses of chlamydial infections could be obtained.