First report of cryptococcosis due to Cryptococcus gattii sensu stricto VGI in an Ivorian HIV negative patient

INTRODUCTION

Cryptococcus gattii species complex is endemic to tropical and subtropical regions and is described as a causative agent of cryptococcosis in immunocompetent individuals.

CASE PRESENTATION

We describe the first case of cryptococcosis in a HIV-negative patient from Ivory Coast infected by Cryptococcus gattii sensu stricto VGI. Isolates were recovered from cerebrospinal fluid (CSF) prior to systemic antifungal treatment up to 42 days after detection of the presence of yeasts in the CSF. Eighteen isolates were recovered, genetic diversity and antifungal susceptibility analyses were performed. All the isolates belonged to the Cryptococcus gattii sensu stricto (B;VGI) and were identified as a new sequence type (ST) 553 by Multilocus Sequence Typing (MLST) analyses. Susceptibility testing showed that all the strains had a wild-type phenotype for fluconazole, amphotericin B and flucytosine. Treatment with fluconazole (1200mg/day) was initiated with success.

CONCLUSION

This is the first case report of the presence of C. gattii sensu stricto VGI in a HIV-negative ivorian patient and the second report of the presence of species from the C. gattii complex species in this country.

pH-operated hybrid silica nanoparticles with multiple H-bond stoppers for colon cancer therapy

Controlled delivery of a chemotherapeutic drug from pH-sensitive hybrid silica nanocarriers efficiently targets colon carcinoma cells. The drug, blocked by cyanuric acid as stopper, is autonomously released inside the cancer cells.

Proteomic analysis of RCL2 paraffin-embedded tissues

Histopathological diagnosis in most of the world's hospitals is based upon formalin-fixed and paraffin-embedded (FFPE) tissues. Although this standard fixation and embedding procedure keeps the tissue in excellent form for morphological and immunohistological analysis, FFPE is inappropriate for nucleic acids and protein studies. We investigated the potential value of RCL2, a new non-toxic fixative, for sparing proteins preserved in paraffin-embedded tissues. Normal colonic mucosa tissue was fixed in RCL2 prior to paraffin embedding (RCL2P), and then processed for quality and quantity of protein conservation, as compared to frozen and FFPE tissues using complementary proteomic analysis approaches. Using 4 different protein extraction protocols, RCL2P tissue consistently showed the highest protein yield. Similar protein patterns were observed with RCL2P and frozen tissues using mono and bi-dimensional electrophoresis. Moreover, membrane, cytoplasmic and nuclear proteins, as well as phosphorylated proteins, were successfully detected using western-blot. Furthermore, protein patterns observed by mass spectrometry analysis after laser-captured microdissection were found to be identical for frozen and RCL2-fixed tissues. At last, immunohistochemistry using various antibodies showed comparable results between both tissue storage methods. We concluded that RCL2 has great potential for performing both morphological and molecular analyses on the same archival paraffin-embedded tissue sample, and can be a new method for investigating protein biomarkers.

Proteomics-based identification of HSP60 as a tumor-associated antigen in early stage breast cancer and ductal carcinoma in situ

The detection of autoantibodies in cancer patients has been shown to constitute an excellent tool for early diagnosis. Because breast cancer still lacks early diagnostic markers, we investigated novel tumor-associated antigens and related autoantibodies in sera from patients with early stage breast cancer compared to autoimmune disease, other cancers, and healthy volunteers, using a proteomics-based approach. Among the 26 protein antigens specifically recognized by early stage breast cancer sera, we focused on Heat Shock Protein 60 (HSP60). Using ELISA, we investigated the frequency of autoantibodies directed against this protein in the sera of 240 individuals, comprising patients with either ductal carcinoma in situ (DCIS) ( n = 49) or early stage breast cancer ( n = 58), other cancers ( n = 20), autoimmune disease ( n = 20), and healthy subjects ( n = 93). Autoantibodies directed against HSP60 were present in 16/49 (31%) early stage breast cancer and 18/58 (32.6%) DCIS patients, compared to 4/93 (4.3%) healthy subjects. In particular, autoantibodies were present in 11/23 patients (47.8%) with high-grade DCIS, compared to 5/26 (19.2%) with low-grade DCIS. HSP60 mRNA levels were significantly higher in primary breast cancer compared to healthy breast tissues. Using immunohistochemistry, we found that HSP60 expression gradually increases from normal through DCIS to invasive tissues. Our results indicate that HSP60 autoantibodies may be of interest in terms of clinical utility for the early diagnosis of breast cancer and more particularly in DCIS. Moreover, HSP60 overexpression during the first steps of breast carcinogenesis may be functionally correlated to tumor growth and/or progression.

Prevalence and intensity of infections in the lymnaeid snail Omphiscola glabra experimentally infected with Fasciola hepatica, Fascioloides magna and Paramphistomum daubneyi

Single and double infections of juvenile Omphiscola glabra (Gastropoda: Lymnaeidae) with Paramphistomum daubneyi and/or Fasciola hepatica were carried out to determine the redial burden and cercarial production in snails dissected at day 60 or at day 75 post-exposure (p.e.) in the laboratory at 20 degrees C. The results were compared with those obtained with single-miracidium infections by Fascioloides magna. Compared to F. hepatica, low values were noted at day 75 p.e. for the prevalence of snail infections with P. daubneyi (4.6-8.3% instead of 23.6-25.9%), the total number of free rediae (10.7-17.9 per snail instead of 26.3-34.7), and that of free cercariae (112.8-136.9 per snail instead of 177.8-248.5). Despite a greater number of free rediae at day 75 p.e. (36.2-45.6 per snail), the prevalences of snail infections with F. magna and cercarial production were similar to those noted for F. hepatica. The results concerning F. hepatica and P. daubneyi might partly be explained by a progressive adaptation of O. glabra to sustain the larval development of these digeneans over the years, as this snail is a natural intermediate host of F. hepatica and P. daubneyi in central France since 1995. Compared with the high number of fully-grown rediae of F. magna in O. glabra, cercarial production seemed limited and this might be explained by the presence of high numbers of rediae which reduced the avaibility of nutrients for cercarial differentiation within the snail.

Cercarial production of Fascioloides magna in the snail Galba truncatula (Gastropoda: Lymnaeidae)

Single-miracidium infections of Fascioloides magna in two populations of Galba truncatula were carried out under laboratory conditions to count free rediae and cercariae in snail cadavers just after death. Cercaria-shedding snails were in low numbers, and their shell height at day 60 p.e. was significantly greater than that of numerous infected snails that died without cercarial shedding. In snails that died between days 44 and 60 p.e. (at 20 degrees C), the numbers of second-generation rediae significantly increased with increasing shell heights of infected snails. First-generation rediae showed insignificant, quantitative variations, while scarce rediae of the third generation were only found in the highest snails. Cercariae were only produced by the second redial generation. In both groups of snails, free cercariae appeared from 6 mm of shell height, and their numbers increased in the upper classes up to 32.9 per snail. Metacercariae were only found from 9 mm of shell height and were in low numbers. The global cercarial production ranged from 163.5 to 210.0 in the highest classes of snail size from both groups and was limited, whereas the mean burdens of free rediae fluctuated from 39.5 to 43.9. The death of numerous infected snails without cercarial shedding might be explained by the presence of a very high number of second-generation rediae simultaneously growing within the body of these snails.

A 6- to 8-day periodicity in cercarial shedding occurred in some Galba truncatula experimentally infected with Fasciola hepatica

A retrospective study on a total of 669 Galba truncatula (three groups) experimentally infected with Fasciola hepatica was carried out to determine why 6- to 8-day interwave intervals, separating the successive waves of cercarial shedding, occurred with a regular pattern in some snails during the whole patent period. In the three groups of snails, the number of cercariae per shedding wave peaked at the second wave and subsequently decreased up to the fifth wave. The mean length of interwave intervals ranged from 6.8 to 7.8 days and only showed insignificant variations. The number of free cercariae recorded at the end of each interwave interval significantly decreased over the patent period. Similar findings were also noted for intraredial cercariae in the first redial generation and the first cohort of the second generation. By contrast, the number of intraredial cercariae significantly increased along the patent period from the second interwave interval. In the case of each interval separately considered, most numerical variations noted for free cercariae or for intraredial cercariae were insignificant. The periodicity of 6.8-7.8 days found for interwave intervals in the present study might correspond to the infradian-type rhythm already reported for the cercarial shedding of F. hepatica. However, snails showing such regular pattern in cercarial shedding along the patent period were few in number, and one may wonder about the reasons of such snails in the case of F. hepatica.

Visna/maedi virus-induced apoptosis involves the intrinsic mitochondrial pathway

Visna/maedi virus (VMV) infection in sheep choroid plexus cells was associated with the appearance of apoptosis and the implication of a caspase-dependent mechanism. Sheep choroid plexus cells were mock-infected or infected with VMV to examine the time course of activation of the intrinsic pathway of apoptosis. The role of mitochondria and related apoptotic events were evaluated. A drop in mitochondrial potential was observed following mitochondrial membrane permeabilization using JC-1, a fluorescent probe, which shifted its fluorescence emission from green to red. Apoptosis Inducing Factor translocated to the nucleus of infected-cells and this translocation was concomitant with the release of cytochrome c in the cytosol of infected-cells and mitochondrial membrane permeabilization which seemed to be regulated by the p53 pathway. Following phosphorylated p53 induced downregulation of bcl-2. In addition, DNA flow cytometric analyses revealed a sub-G peak characteristic of an apoptotic population that gradually appeared as virus infection progressed. No cell cycle arrest was detected in infected cells while p21 expression increased. It was concluded that VMV apoptosis is mediated in part by the activation of p53 and the intrinsic mitochondrial apoptotic pathway.

AZT inhibits Visna/maedi virus -induced apoptosis

Visna/maedi virus (VMV) causes severe encephalitis and a progressive demyelinating disease in sheep. Previous in vitro studies have demonstrated that VMV-infection leads to apoptosis in sheep choroid plexus cells (SCPC) via induction of both intrinsic and extrinsic pathways with subsequent activation of caspases. 3' azido-2',3'-deoxythymidine (AZT) is a potent and selective Human immunodeficiency virus 1 (HIV-1) reverse transcriptase inhibitor, widely used in antiretroviral therapy; however its effects on retrovirus-induced apoptosis are unknown. Using diverse strategies to detect apoptosis, we analysed the broad range effect of AZT treatment on inhibition of VMV-induced apoptosis. First, we found that AZT treatment inhibited the appearance of characteristic apoptotic morphologic changes documented by DAPI staining and oligonucleosomal DNA laddering. Secondly, AZT treatment inhibited caspase cascade and resulted in (i) diminished caspase-3, -8 and -9 activities and (ii) no fluorescein isothiocynate-[VAD]-fluoromethylketone (FITC-VAD-FMK) in situ labelling in VMV-infected cells treated with AZT. Finally, immunocytochemistry indicated that VMV-infection of SCPC induced the subsequent release of apoptosis inducing factor (AIF), whereas AZT treatment inhibited AIF leakage. Consequently, the anti-apoptotic effects of AZT are not restricted, since AZT treatment blocks all the apoptotic pathways induced during VMV-infection.

Implication of caspases during maedi-visna virus-induced apoptosis

Maedi-visna virus (MVV) causes encephalitis, pneumonia and arthritis in sheep. In vitro, MVV infection and replication lead to strong cytopathic effects characterized by syncytia formation and subsequent cellular lysis. It was demonstrated previously that MVV infection in vitro induces cell death of sheep choroid plexus cells (SCPC) by a mechanism that can be associated with apoptotic cell death. Here, the relative implication of several caspases during acute infection with MVV is investigated by employing diverse in vitro and in situ strategies. It was demonstrated using specific pairs of caspase substrates and inhibitors that, during in vitro infection of SCPC by MVV, the two major pathways of caspase activation (i.e. intrinsic and extrinsic pathways) were stimulated: significant caspase-9 and -8 activities, as well as caspase-3 activity, were detected. To study the role of caspases during MVV infection in vitro, specific, cell-permeable, caspase inhibitors were used. First, these results showed that both z-DEVD-FMK (a potent inhibitor of caspase-3-like activities) and z-VAD-FMK (a broad spectrum caspase inhibitor) inhibit caspase-9, -8 and -3 activities. Second, both irreversible caspase inhibitors, z-DEVD-FMK and z-VAD-FMK, delayed MVV-induced cellular lysis as well as virus growth. Third, during SCPC in vitro infection by MVV, cells were positively stained with FITC-VAD-FMK, a probe that specifically stains cells containing active caspases. In conclusion, these data suggest that MVV infection in vitro induces SCPC cell death by a mechanism that is strongly dependent on active caspases.