No abstract

The skin offers a tissue site accessible for delivery of gene-based therapeutics. To develop the capability for sustained systemic polypeptide delivery via cutaneous gene transfer, we generated and injected pseudotyped HIV-1 lentiviral vectors intradermally at a range of doses into human skin grafted on immune-deficient mice. Unlike Moloney murine leukemia virus (MLV)-based retrovectors, which failed to achieve detectable cutaneous gene transfer by this approach, lentivectors effectively targeted all major cell types within human skin tissue, including fibroblasts, endothelial cells, keratinocytes, and macrophages. After a single injection, lentivectors encoding human erythropoietin (EPO) produced dose-dependent increases in serum human EPO levels and hematocrit that increased rapidly within one month and remained stable subsequently. Delivered gene expression was confined locally at the injection site. Excision of engineered skin led to rapid and complete loss of human EPO in the bloodstream, confirming that systemic EPO delivery was entirely due to lentiviral targeting of cells within skin rather than via spread of the injected vector to visceral tissues. These findings indicate that the skin can sustain dosed systemic delivery of therapeutic polypeptides via direct lentivector injection and thus provide an accessible and reversible approach for gene-based delivery to the bloodstream.

The PCR-restriction enzyme analysis method appears to be a more sensitive detection and identification technique for onychomycosis than conventional methods, and has considerable diagnostic value.

A 41‐year‐old man noted the presence of a punched‐out ulcer on the anterior midline of the neck. There was no previous history of trauma or radiation to the head and neck region. Physical examination showed a draining sinus surrounded by a cribriform scar on the anterior midline of the neck ( Fig. 1). There was no adenopathy in the neck. The head and neck were otherwise normal, as were T3 and T4, routine blood and urine tests, and chest X‐rays. Thyroid scan was performed which demonstrated normal uptake and normal location of the thyroid gland. Computed tomographic scan showed a 2.5×1.0×1.0‐cm‐sized ovoid, hypodense cystic mass extending to the cricoid cartilage. Because there was doubt as to the extent of the fistulous tract and its ramifications, a roentgen study of the tract after injection of a contrast medium was performed. The fistulogram showed that the injected contrast medium was observed at the base of the tongue through a faintly opacified thread‐like fistulous tract from the skin. 1 Punched‐out ulcer surrounded by cribriform scar on the anterior midline of the neck At surgical exploration, a thyroglossal duct tract was identified and a Sistrunk procedure was performed. This involved the removal of the thyroglossal duct cyst and the central portion of the hyoid bone, and the tracing of the thyroglossal duct tract to the foramen cecum at the base of the tongue. The pathology of the thyroglossal mass showed a thyroglossal duct cyst lined by columnar epithelium and small acini, with solid groups of large polyhedrial or round cells with pleomorphic hyperchromatic nuclei and eosinophilic granular cytoplasm, consistent with Hürthle cell adenoma ( Figs 2 and 3). No evidence of capsular invasion or penetration was observed. The patient was discharged in a good condition 1 week later, and was well at follow‐up 6 months later. 2 Hürthle cell adenoma (right) and thyroglossal duct cyst lined by columnar epithelium (left) are seen on the photomicrograph of the resected specimen (hematoxylin and eosin stain;×50) 3 High‐power photomicrograph of the Hürthle cell adenoma showing polyhedrial or round cells with abundant eosinophilic granular cytoplasm and pleomorphic hyperchromatic eccentric nuclei (hematoxylin and eosin stain;×400)