The masquerading presentation of a systemic anaplastic large cell lymphoma, ALK positive: a case report and review of the literature

We report an unusual case of systemic anaplastic large cell lymphoma (ALCL), ALK positive with leukemic involvement in a 57-year-old woman. The patient presented with a fulminant respiratory infection unresponsive to treatment requiring intensive care and ventilatory support. The CT scan demonstrated mediastinal and bilateral lymphadenopathy. On peripheral smear a few atypical lymphocytes were visualized. Based on the increasing number of atypical lymphocytes in the daily peripheral bloodsmears, the diagnosis ALCL was suggested. Definitive diagnosis was made on a bone marrow biopsy, with lymphocytes being immunoreactive for CD30, EMA, and ALK. Leukemic peripheral blood involvement in ALCL is an uncommon clinicopathologic entity with unfavorable prognosis. The case we present is perhaps unusual in that a complete respons was achieved, highlighting the importance of prompt diagnosis and judicious management.

Enzymatic functionalization of a nanobody using protein insertion technology

Antibody-based products constitute one of the most attractive biological molecules for diagnostic, medical imagery and therapeutic purposes with very few side effects. Their development has become a major priority of biotech and pharmaceutical industries. Recently, a growing number of modified antibody-based products have emerged including fragments, multi-specific and conjugate antibodies. In this study, using protein engineering, we have functionalized the anti-hen egg-white lysozyme (HEWL) camelid VHH antibody fragment (cAb-Lys3), by insertion into a solvent-exposed loop of the Bacillus licheniformis β-lactamase BlaP. We showed that the generated hybrid protein conserved its enzymatic activity while the displayed nanobody retains its ability to inhibit HEWL with a nanomolar affinity range. Then, we successfully implemented the functionalized cAb-Lys3 in enzyme-linked immunosorbent assay, potentiometric biosensor and drug screening assays. The hybrid protein was also expressed on the surface of phage particles and, in this context, was able to interact specifically with HEWL while the β-lactamase activity was used to monitor phage interactions. Finally, using thrombin-cleavage sites surrounding the permissive insertion site in the β-lactamase, we reported an expression system in which the nanobody can be easily separated from its carrier protein. Altogether, our study shows that insertion into the BlaP β-lactamase constitutes a suitable technology to functionalize nanobodies and allows the creation of versatile tools that can be used in innovative biotechnological assays.

Rapid and easy development of versatile tools to study protein/ligand interactions

The system described here allows the expression of protein fragments into a solvent-exposed loop of a carrier protein, the beta-lactamase BlaP. When using Escherichia coli constitutive expression vectors, a positive selection of antibioresistant bacteria expressing functional hybrid beta-lactamases is achieved in the presence of beta-lactams making further screening of correctly folded and secreted hybrid beta-lactamases easier. Protease-specific recognition sites have been engineered on both sides of the beta-lactamase permissive loop in order to cleave off the exogenous protein fragment from the carrier protein by an original two-step procedure. According to our data, this approach constitutes a suitable alternative for production of difficult to express protein domains. This work demonstrates that the use of BlaP as a carrier protein does not alter the biochemical activity and the native disulphide bridge formation of the inserted chitin binding domain of the human macrophage chitotriosidase. We also report that the beta-lactamase activity of the hybrid protein can be used to monitor interactions between the inserted protein fragments and its ligands and to screen neutralizing molecules.

Susceptibility testing of fluconazole by the NCCLS broth macrodilution method, E-test, and disk diffusion for application in the routine laboratory

Antifungal susceptibility testing may be an important aid in the treatment of patients with life-threatening yeast infections. In order to establish the suitability of different susceptibility test methods for fluconazole with yeasts, the Rosco tablet and the E-test were compared with the gold standard NCCLS broth macrodilution method for 106 yeast strains. These included 102 clinical isolates of Candida spp., including Candida glabrata (n = 30), Candida albicans (n = 20), Candida tropicalis (n = 13), Candida parapsilosis (n = 10), Candida krusei (n = 8), plus Cryptococcus neoformans (n = 3), Saccharomyces cerevisiae (n = 2), and 16 strains belonging to other Candida spp. Four American Type Culture Collection strains of Candida were included as quality controls. The NCCLS method was found to be too complex and labor-intensive for routine testing. The E-test is an accurate alternative, but experience in determining MICs and careful attention to procedural details are critically important. The Rosco tablet showed the best agreement with the NCCLS reference method, especially when newly established breakpoints of R < or = 10 mm and S > or = 21 mm were used.

Detection time of drugs of abuse in urine

Estimating the detection time of a drug in urine is complex because of many different influencing factors and the lack of experimental data. Detection times vary depending on dose and route of administration, metabolism and characteristics of the screening and confirmation assays. Using a cut-off value of 1000 ng/mL, urinary samples can be positive for amphetamine for up to 5 days after intake of the drug. At the lower 300 ng/mL cut-off, amphetamine will be detectable one day longer. Very few data are available for designer amphetamines. After smoking one marijuana cigarette, THCCOOH (9-carboxy-delta 9 tetrahydrocannabinol) is detectable (using a screening cut-off of 50 ng/mL) for 2-4 days. More frequent use will be detectable for almost 1 month, exceptionally 3 months. Immunoassays to detect cocaine are targeted against the metabolite benzoylecgonine and use a cut-off of 300 ng/mL. An intravenous dose of 20 mg cocaine can be detected for 1.5 days. Street doses (administered via different routes) are detectable up to 1 week, and extremely high doses up to 3 weeks. Heroin rapidly metabolizes to 6-acetylmorphine and morphine. Immunoassays for heroin are calibrated with morphine but important cross-reactivity occurs and positive results must be confirmed by GC-MS. Experimental data for total morphine using a cut-off of 300 ng/mL suggest a detection time of 1 to 1.5 days for relatively low doses of heroin (3-12 mg) administered via i.v., IN or i.m. route.