Biomedical subjects

Christopher Janson

Publications and source records attributed to Christopher Janson.

3 recordsLinked to original sources

PubMed2006

Decoding the research exemption.

While debate continues as to whether genetic sequences, which many argue represent natural phenomena rather than inventions, should be subject to standard patent protections, issuance of patents that claim DNA sequences remains common practice. In an attempt to insulate researchers from patent claims that could hinder scientific progress, many countries have provided general exemptions for scientific research. However, there is no international consensus about the extent of required protections, and even existing exemptions vary widely in clarity and are limited in practical application. We believe that gene patents raise several unique issues that are inadequately handled by the current research exemptions.

Animals↗

PubMed2005

Improvement of quantitative testing of liver function in patients with chronic hepatitis C after installment of antiviral therapy.

AIM: To investigate if and to what extent antiviral therapy influenced a broad panel of quantitative testing of liver function (QTLF). METHODS: Fifty patients with chronic hepatitis C were either treated with interferon (n = 8), interferon/ribavirin (n = 19) or peg-interferon/ribavirin (n = 23). Quantitative testing of liver function, including aminopyrine breath test (ABT), galactose elimination capacity (GEC), sorbitol clearance (SCl) and indocyanine green clearance (ICG) was performed before and 3 mo after initiation of antiviral therapy. RESULTS: After 3 mo of antiviral treatment, 36 patients showed normal transaminases and were negative for HCV-RNA, 14 patients did not respond to therapy. ABT and GEC as parameters of microsomal and cytosolic liver function were reduced in all patients before therapy initiation and returned to normal values in the 36 therapy responders after 3 mo. Parameters of liver perfusion (SCl and ICG) were not affected by antiviral therapy. In the 14 non-responders, no changes in QTLF values were observed during the treatment period. CONCLUSION: ICG and SCl remained unaffected in patients with chronic hepatitis C, while ABT and GEC were significantly compromised. ABT and GEC normalized in responders to antiviral therapy. Early determination of ABT and GEC may differentiate responders from non-responders to antiviral treatment in hepatitis C.

Adult↗

PubMed2002

Clinical protocol. Gene therapy of Canavan disease: AAV-2 vector for neurosurgical delivery of aspartoacylase gene (ASPA) to the human brain.

This clinical protocol describes virus-based gene transfer for Canavan disease, a childhood leukodystrophy. Canavan disease, also known as Van Bogaert-Bertrand disease, is a monogeneic, autosomal recessive disease in which the gene coding for the enzyme aspartoacylase (ASPA) is defective. The lack of functional enzyme leads to an increase in the central nervous system of the substrate molecule, N-acetyl-aspartate (NAA), which impairs normal myelination and results in spongiform degeneration of the brain. No effective treatment currently exists; however, virus-based gene transfer has the potential to arrest or reverse the course of this otherwise fatal condition. This procedure involves neurosurgical administration of approximately 900 billion genomic particles (approximately 10 billion infectious particles) of recombinant adeno-associated virus (AAV) containing the aspartoacylase gene (ASPA) directly to affected regions of the brain in each of 21 patients with Canavan disease. Pre- and post-delivery assessments include a battery of noninvasive biochemical, radiological, and neurological tests. This gene transfer study represents the first clinical use of AAV in the human brain and the first instance of viral gene transfer for a neurodegenerative disease.

Amidohydrolases↗