Biomedical subjects

R Pettis

Publications and source records attributed to R Pettis.

3 recordsLinked to original sources

PubMed2006

Evaluating new hypodermic and intradermal injection devices.

The wicking spear gravimetric method was selected as the easier and the most consistent method for fluid leakage collection. The kit uses the glass sample collection tube to store the wicking spears before and after fluid leakage collection. It has been shown to provide reliable equipment for wicking spear intermediate storage and shipment to central laboratories for weight/mass measurements. Weighting the collection tubes with wicking spear inside, in a central laboratory in a batch fashion, before and after fluid collection, contributes to minimising operator and balance errors on method accuracy. The volume detection threshold is below 2 microL and the measurement error, even after 12 days of storage at room temperature, is below 1 microL, which is considered not to be clinically relevant.

Equipment Design↗

PubMed1999

Transgene expression in the guinea pig cochlea mediated by a lentivirus-derived gene transfer vector.

The utility of lentivirus as a gene delivery vector in the cochlea was evaluated in vitro and in vivo. Lentivirus transduction was assessed through expression analysis of a reporter gene, green fluorescent protein (GFP), integrated within the viral genome. In vitro characterization of lentivirus-GFP was assessed by infection of explants from cochleas of neonatal rat. The lentiviral vector transduced both spiral ganglion neurons (SGNs) and glial cells. In vivo characterization of lentivirus-GFP was assessed by directly infusing the vector into the guinea pig cochlea via an osmotic minipump. Sections of lentivirus-infused cochlea revealed a highly restricted fluorescence pattern limited to the periphery of the perilymphatic space. Transduction of SGNs and glial cells by lentivirus in vitro but not in vivo suggests limited dissemination of the viral vector from the perilymphatic space. The cellular and tissue architecture of the lentivirus-infused cochlea was intact and free of inflammation. Restricted transduction of cell types confined to the periphery of the perilymphatic space by the lentivirus is ideal for stable production of gene products secreted into the perilymph.

Animals↗

PubMed1999

Cationic liposome mediated transgene expression in the guinea pig cochlea.

Sensorineural hearing loss affects nearly 10% of the American population that is refractory to conventional therapy. Gene therapy represents an intervention with potential therapeutic efficacy. We studied the feasibility of cationic liposome mediated gene transfer within the guinea pig cochlea in vivo following direct microinjection into the cochlea. Transgene expression was persistent up to 14 days in the neurosensory epithelia and surrounding tissue without toxicity and inflammation in the target organ. This study represents the first successful use of cationic liposomes for cochlear gene transfer thus providing a safe and rapid alternative to the use of recombinant viral vectors in gene therapy for inner ear disorders.

Animals↗