Biomedical subjects

Gist H Farr

Publications and source records attributed to Gist H Farr.

5 recordsLinked to original sources

PubMed2005

Eomesodermin is a localized maternal determinant required for endoderm induction in zebrafish.

In zebrafish, endoderm induction occurs in marginal blastomeres and requires Casanova (Cas), the first endoderm-specific factor expressed in the embryo. Whereas the transcription factors Gata5 and Bon are necessary and sufficient for cas expression in marginal blastomeres, Bon and Gata5 are unable to induce cas in animal pole cells, suggesting that cas expression requires an additional, unidentified factor(s). Here, we show that cas expression depends upon the T box transcription factor Eomesodermin (Eomes), a maternal determinant that is localized to marginal blastomeres. Eomes synergizes potently with Bon and Gata5 to induce cas, even in animal pole blastomeres. We show that Eomes is required for endogenous endoderm induction, acting via an essential binding site in the cas promoter. Direct physical interactions between Eomes, Bon, and Gata5 suggest that Eomes promotes endoderm induction in marginal blastomeres by facilitating the assembly of a transcriptional activating complex on the cas promoter.

Animals↗

PubMed2004

Long-term results of a phase III trial comparing once-daily radiotherapy with twice-daily radiotherapy in limited-stage small-cell lung cancer.

PURPOSE: This Phase III study was performed to determine whether twice-daily (b.i.d.) radiotherapy (RT) resulted in better survival than once-daily (q.d.) RT for patients with limited-stage small-cell lung cancer (LD-SCLC). METHODS AND MATERIALS: A total of 310 patients with LD-SCLC initially received three cycles of etoposide and cisplatin. Subsequently, the 261 patients without significant progression were randomized to two cycles of etoposide and cisplatin plus either q.d. RT (50.4 Gy in 28 fractions) or split-course b.i.d. RT (24 Gy in 16 fractions, a 2.5-week break, and 24 Gy in 16 fractions) to the chest. Patients then received a sixth cycle of etoposide and cisplatin followed by prophylactic cranial RT. RESULTS: Follow-up ranged from 4.6 to 11.9 years (median, 7.4 years). The median survival and 5-year survival rate from randomization was 20.6 months and 21% for patients who received q.d. RT compared with 20.6 months and 22% for those who received b.i.d. RT (p = 0.68), respectively. No statistically significant differences were found in the rates of progression (p = 0.68), intrathoracic failure (p = 0.45), in-field failure (p = 0.62), or distant failure (p = 0.82) between the two treatment arms. No statistically significant difference was found in the overall rate of Grade 3 or worse (p = 0.83) or Grade 4 or worse toxicity (p = 0.95). Grade 3 or worse esophagitis (p = 0.05) was more common in the b.i.d. arm. Grade 5 toxicity occurred in 4 (3%) of 130 patients who received b.i.d. RT compared with 0 (0%) of 131 who received q.d. RT (p = 0.04). CONCLUSION: Although this study did not demonstrate an advantage to split-course b.i.d. RT, the long-term survival was favorable, likely reflecting the positive influences of concurrent combined modality therapy and prophylactic cranial RT.

Adult↗

PubMed2004

Phase II study of oral etoposide and intravenous paclitaxel in extensive-stage small cell lung cancer.

BACKGROUND: This study evaluated the activity and tolerance for the combination of oral etoposide and paclitaxel as first-line therapy for patients with extensive SCLC. METHODS: A total of 57 patients were enrolled in this study. A cycle of chemotherapy consisted of oral etoposide administered as 50 mg BID on days 1 through 10 and paclitaxel administered as 150 mg/m(2) IV (3 h infusion) along with the first dose of etoposide on day 10. Patients were assessed for response to therapy (regression, stable disease, progression), survival, time to disease progression, and toxicity. RESULTS/CONCLUSIONS: Fifty-five patients were evaluable for efficacy parameters. Among the 55 patients, there were six with complete regression of disease, 18 with partial regression, 11 with regression, five with stable disease, and 15 with progressive disease, yielding an overall response rate of 63.6% (95% confidence interval, 50.0-76.0%). The 6-month and 1-year progression-free survival rates were 48.2 and 18.9%, respectively. The median time to disease progression was 5.8 months. The overall survival rates were 67.3% at 6 months and 41.8% at 1 year. The combination of oral etoposide and paclitaxel demonstrated significant efficacy as first-line therapy for extensive SCLC, with an overall response rate of 63.6% for 55 evaluable patients. In addition, the treatment was well tolerated with no unexpected toxicities.

Administration, Oral↗

PubMed2004

Pilot studies of single and combination antiretroviral therapy in patients with primary biliary cirrhosis.

OBJECTIVE: Preliminary reports suggest that patients with primary biliary cirrhosis (PBC) have evidence of human betaretrovirus infection. The aim of this study was to determine whether antiviral therapy impacts on the disease process. METHODS: We conducted two consecutive open-labeled, nonrandomized, 1-yr pilot studies; the first with lamivudine 150 mg/day and the second with Combivir combination therapy using lamivudine 150 mg and zidovudine 300 mg twice a day. Eleven PBC patients enrolled in each study, seven patients were entered into both studies, and one patient was withdrawn from each study due to side effects. RESULTS: Evaluation of liver biopsies before and after lamivudine therapy showed a 4-5 increase in necroinflammatory score, a 1-1.5 elevation in bile duct injury, with little change in the percentage of portal tracts with bile ducts (50-52%). None of the patients in the lamivudine study normalized alkaline phosphatase. Histological assessment following Combivir therapy revealed a 6 to 4 improvement in necroinflammatory score (p < 0.03, 95% CI: 0.53-2.33), a 3 to 1 reduction in bile duct injury (p < 0.02, 95% CI: 1.08-2.07), and a 45-75% increase in portal tracts with bile ducts (p < 0.05, 95% CI: 0.02-0.29). In the Combivir cohort, five patients normalized alkaline phosphatase and four developed normal AST, ALT, and alkaline phosphatase. CONCLUSIONS: Histological and biochemical endpoints were achieved in the Combivir pilot study suggesting a larger placebo-controlled trial is required as a proof of principle to assess whether antiviral therapy impacts the PBC disease process.

Adult↗

PubMed2003

GBP binds kinesin light chain and translocates during cortical rotation in Xenopus eggs.

In Xenopus, axis development is initiated by dorsally elevated levels of cytoplasmic beta-catenin, an intracellular factor regulated by GSK3 kinase activity. Upon fertilization, factors that increase beta-catenin stability are translocated to the prospective dorsal side of the embryo in a microtubule-dependent process. However, neither the identity of these factors nor the mechanism of their movement is understood. Here, we show that the GSK3 inhibitory protein GBP/Frat binds kinesin light chain (KLC), a component of the microtubule motor kinesin. Upon egg activation, GBP-GFP and KLC-GFP form particles and exhibit directed translocation. KLC, through a previously uncharacterized conserved domain, binds a region of GBP that is required for GBP translocation and for GSK3 binding, and competes with GSK3 for GBP. We propose a model in which conventional kinesin transports a GBP-containing complex to the future dorsal side, where GBP dissociates and contributes to the local stabilization of beta-catenin by binding and inhibiting GSK3.

Adaptor Proteins, Signal Transducing↗