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Donald McDonald

Publications and source records attributed to Donald McDonald.

9 recordsLinked to original sources
PubMed2006

Preclinical evaluation of an anti-alpha5beta1 integrin antibody as a novel anti-angiogenic agent.

Integrin alpha5beta1, the principal fibronectin receptor, is an important survival factor, playing a key role in angiogenesis. Angiogenesis is critical for tumor growth, and anti-angiogenic therapies have met clinical success. To validate the therapeutic potential of an anti-alpha5beta1 strategy, we generated volociximab (M200) a chimeric human IgG4 version of the alpha5beta1 function-blocking murine antibody IIA1; and F200, the Fab derivative. Volociximab, F200 and IIA1 showed similar activity by ELISA (EC50= 0.2nM), Biacore (Kd= 0.1-0.4nM) and inhibition of fibronectin binding (IC50= 2-3nM). The inhibitory potential of alpha5beta1 antibodies was compared to HuMV833, an anti-VEGF antibody. Both volociximab and HuMV833 inhibited HUVEC proliferation (IC50 of volociximab = 0.2-0.5nM; IC50 of HuMV833 = 45nM). However, IIA1, volociximab and F200 were also potent inhibitors of an in vitro model of angiogenesis (HUVEC tube formation assay), unlike HuMV833. Additionally, volociximab inhibited in vitro tube formation induced by VEGF and/or bFGF, suggesting a mechanism of action independent of growth factor stimulus. In fact, inhibition of alpha5beta1 function by volociximab induced apoptosis of actively proliferating, but not resting, endothelial cells. Volociximab does not cross-react with rodent alpha5beta1, therefore in vivo validation of an anti-alpha5beta1 approach was conducted in a cynomolgus model of choroidal revascularization. Volociximab and F200 were potent inhibitors of neovessel formation in this model. These data demonstrate that volociximab has therapeutic potential in diseases in which new vessel formation is a component of the pathology.

Angiogenesis Inhibitors↗
PubMed2004

The total percentage of biopsy cores with cancer improves the prediction of pathological stage after radical prostatectomy.

OBJECTIVE: To examine whether the simple variable 'percentage of cancer-positive biopsy cores' is a significant predictor of true pathological stage after radical prostatectomy and can be used to improve pathological stage prediction by simple means. PATIENTS AND METHODS: In all, 375 patients had a radical prostatectomy for localized prostate cancer in two UK centres; 260 had complete preoperative staging information. Logistic regression was used and predicted probability graphs constructed to assess predictors of pathological stage. RESULTS: In this study, only PSA (P = 0.004) and percentage cancer-positive biopsy cores (P < 0.001) were significant predictors of pathological stage. The final model was an acceptable classifier for pathological stage (area under the receiver operating characteristic curve 0.76, specificity 85%, sensitivity 47%). A patient with a PSA of 10 ng/mL and one of six cores positive for cancer would have a predicted probability of extraprostatic disease of 20%, whereas the same patient with all six biopsy cores positive would have a predicted probability of extraprostatic disease of 80%. CONCLUSIONS: The percentage of cancer-positive biopsy cores significantly predicts the disease stage after radical prostatectomy. This variable is easy to obtain by the clinician and avoids the need to estimate the percentage of biopsy tissue infiltrated by cancer. This readily available information can easily be computed and may help to counsel patients about realistic expectations of organ-confined disease in relation to surgery as a treatment option.

Aged↗
PubMed2003

GNOM alone.

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Arabidopsis↗
PubMed2003

Tip of the POP2.

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Arabidopsis↗