Ocular tuberculosis presenting with a conjunctival granuloma

An 18-year-old female patient was referred with complaints of tearing and redness in the left eye for 3 months after a mild ocular trauma with a turkey feather. She was treated with topical antibiotics and corticosteroids with no improvement. Slit-lamp examination of the left eye showed a vascularized lesion with a polypoidal appearance due to multiple contiguous micronodules on the temporal and inferior bulbar conjunctiva. Results of the anterior and posterior segment examination were unremarkable in both eyes. A biopsy specimen of the conjunctival mass showed multiple tuberculoid granulomas composed of epithelioid histiocytes with associated Langhan's type multinucleate giant cells and a necrotic nodule surrounded by histiocytes and giant cells. The Mantoux test was positive with induration of 15mm. The patient was prescribed antituberculosis therapy. Three months after treatment initiation, the conjunctival lesions had resolved. Mycobacterium tuberculosis should be considered in cases of unilateral chronic recalcitrant conjunctivitis. Biopsy of a conjunctival mass is of utmost importance to establish a definite diagnosis.

Direct Amperometric Sensing of Fish Nodavirus RNA Using Gold Nanoparticle/DNA-Based Bioconjugates

We describe the design of a simple and highly sensitive electrochemical bioanalytical method enabling the direct detection of a conserved RNA region within the capsid protein gene of a fish nodavirus, making use of nanostructured disposable electrodes. To achieve this goal, we select a conserved region within the nodavirus RNA2 segment to design a DNA probe that is tethered to the surface of nanostructured disposable screen-printed electrodes. In a proof-of-principle test, a synthetic RNA sequence is detected based on competitive hybridization between two oligonucleotides (biotinylated reporter DNA and target RNA) complimentary to a thiolated DNA capture probe. The method is further validated using extracted RNA samples obtained from healthy carrier Sparus aurata and clinically infected Dicentrarchus labrax fish specimens. In parallel, the sensitivity of the newly described biosensor is compared with a new real-time RT-PCR protocol. The current differences measured in the negative control and in presence of each concentration of target RNA are used to determine the dynamic range of the assay. We obtain a linear response (R² = 0.995) over a range of RNA concentrations from 0.1 to 25 pM with a detection limit of 20 fM. The results are in good agreement with the results found by the RT-qPCR. This method provides a promising approach toward a more effective diagnosis and risk assessment of viral diseases in aquaculture.