Biomedical subjects

Ren Yu

Publications and source records attributed to Ren Yu.

4 recordsLinked to original sources

PubMed2006

Dynamics of interferon-specific gene expression in peripheral blood of interferon alfa-naïve patients with genotype 1 chronic hepatitis C infection treated with albumin-interferon alfa.

Albumin-interferon alfa (alb-IFN) is a novel recombinant protein derived from IFNalpha-2b genetically fused to human albumin, which combines in a single polypeptide the antiviral properties of IFNalpha with the long serum half-life of albumin. Interferon alfa (IFNalpha) mediated biological responses stem from the engagement of IFNalpha with its target receptor and subsequent modulation of interferon-specific gene (ISG) expression. The dynamics of ISG expression were evaluated in a Phase 2a study conducted in IFNalpha naïve patients with genotype 1 chronic hepatitis C (CHC) treated with alb-IFN. Whole blood was obtained pre-dose and on days 7 and 28 from 47 patients enrolled to receive two subcutaneous injections of alb-IFN 14 days apart in five dose cohorts ranging from 200 to1200mug. Gene expression of nine candidate genes including four ISGs was determined by a TaqMan Real-time PCR assay. There was sustained >5-fold median induction on days 7 and 28 of the ISG's- OAS1, IRF7, IFI44 and IFI27. While all subjects showed a molecular response to alb-IFN, individual variability in pre-treatment gene expression levels and fold of modulation during treatment was observed. At days 7 and 28, induction of OAS1, IFI44 and IRF7 showed significant pair-wise correlation in individual patients (r>0.7 and P<0.001). There was no correlation of baseline expression or induction of gene expression with antiviral response. In conclusion, alb-IFN demonstrated robust induction of ISG that was consistent with the molecular response associated with an IFNalpha.

Journal Article↗

PubMed2006

A phase 2 study to evaluate the antiviral activity, safety, and pharmacokinetics of recombinant human albumin-interferon alfa fusion protein in genotype 1 chronic hepatitis C patients.

BACKGROUND/AIMS: Recombinant human albumin-interferon alfa (alb-IFN) is a novel 85.7-kD recombinant protein consisting of interferon alfa-2b genetically fused to human serum albumin. METHODS: A phase 2, open-label, dose-ranging study was conducted in IFN-alfa-naïve patients with genotype 1 chronic hepatitis C to evaluate the antiviral activity, safety, and pharmacokinetics of alb-IFN. Fifty-six patients were enrolled to receive two subcutaneous injections of alb-IFN 14 days apart in five dose cohorts of 200, 450, 670, 900, and 1,200 microg. RESULTS: A 2 log(10) IU/mL or greater reduction in hepatitis C virus (HCV) RNA at Week 4 was observed in 69% (18/26) of patients who received the higher alb-IFN doses of 900 and 1,200 microg. The mean HCV RNA reduction at Week 4 in these two higher-dose cohorts was 3.2 log(10) IU/mL. Modeling of viral kinetics demonstrated a biphasic response that was dose dependent. Adverse events were mostly mild to moderate in severity. The most common adverse events were headache (73%), chills (63%), fatigue (61%), and arthralgia (55%). The median terminal half-life was 141 h consistent with previous alb-IFN data from IFN-alfa-experienced patients. CONCLUSIONS: Alb-IFN demonstrated significant antiviral activity and was well tolerated in patients with HCV genotype 1 infection.

Adult↗

PubMed2003

Early period of fracture healing in ovariectomized rats.

OBJECTIVE: To evaluate the effect of osteoporosis on fracture healing through observing the histomorphological changes, bone mineral density of callus and expression and distribution of transforming growth factor beta 1 (TGF-beta1), basic fibroblast growth factor (bFGF) and bone morphogenetic protein-2 (BMP-2) in ovariectomized rats. METHODS: Sixty female Sprague-Dawley rats (aged 12 weeks and weighing 235 g on average) were randomly divided into an ovariectomized (OVX) group (n=30) and a sham-operated (SO) group (n=30). Ovariectomy was performed in the OVX rats and same incision was made in the SO rats. Three months later, fracture of femoral shaft was made on all the rats. Then they were killed at different time points. Callus formation was observed with histological and immunohistochemical methods. RESULTS: A reduction in callus and bone mineral density in the healing femur and a decrease of osteoblasts expressing TGF-beta1 near the bone trabecula were observed in the OVX rats 3-4 weeks after fracture. Histomorphological analysis revealed a higher content of soft callus in the OVX rats than that in the SO rats. Immunohistochemistry results showed that no remarkable difference in expression and distribution of BMP-2 and bFGF between the OVX and SO groups was found. CONCLUSIONS: Osteoporosis influences the quantity and quality of callus during the early period of fracture healing. The effect of osteoporosis on fracture healing has no relationship with the expression of BMP-2 or bFGF. The decreased expression of TGF-beta1 in osteoblasts may cause a decrease in quality of fracture healing after osteoporosis.

Animals↗

PubMed2002

Methods for assessing reproducibility of clustering patterns observed in analyses of microarray data.

MOTIVATION: Recent technological advances such as cDNA microarray technology have made it possible to simultaneously interrogate thousands of genes in a biological specimen. A cDNA microarray experiment produces a gene expression 'profile'. Often interest lies in discovering novel subgroupings, or 'clusters', of specimens based on their profiles, for example identification of new tumor taxonomies. Cluster analysis techniques such as hierarchical clustering and self-organizing maps have frequently been used for investigating structure in microarray data. However, clustering algorithms always detect clusters, even on random data, and it is easy to misinterpret the results without some objective measure of the reproducibility of the clusters. RESULTS: We present statistical methods for testing for overall clustering of gene expression profiles, and we define easily interpretable measures of cluster-specific reproducibility that facilitate understanding of the clustering structure. We apply these methods to elucidate structure in cDNA microarray gene expression profiles obtained on melanoma tumors and on prostate specimens.

Cluster Analysis↗