Methods of model reduction for large-scale biological systems: a survey of current methods and trends

Complex models of biochemical reaction systems have become increasingly common in the systems biology literature. The complexity of such models can present a number of obstacles for their practical use, often making problems difficult to intuit or computationally intractable. Methods of model reduction can be employed to alleviate the issue of complexity by seeking to eliminate those portions of a reaction network that have little or no effect upon the outcomes of interest, hence yielding simplified systems that retain an accurate predictive capacity. This review paper seeks to provide a brief overview of a range of such methods and their application in the context of biochemical reaction network models. To achieve this, we provide a brief mathematical account of the main methods including timescale exploitation approaches, reduction via sensitivity analysis, optimisation methods, lumping, and singular value decomposition-based approaches. Methods are reviewed in the context of large-scale systems biology type models, and future areas of research are briefly discussed

Management strategy for facial arteriovenous malformations

Arteriovenous malformations (AVMs) are uncommon errors of vascular morphogenesis; haemodynamically, they are high-flow lesions. Approximately 50% of AVMs are located in the craniofacial region. Subtotal excision or proximal ligation of the feeding vessel frequently results in rapid progression of the AVMs. Hence, the correct treatment consists of highly selective embolisation (super-selective) followed by complete resection 24-48 hours later. We treated 20 patients with facial arteriovenous malformation by using this method. Most of the lesions (80%) were located within the cheek and lip. There were no procedure related complications and cosmetic results were excellent