Intracranial collateral circulation and its role in neurovascular pathology

Background Collateral circulation is a vascular network which maintains the blood flow after the partial blockage of primary vascular pathways. This acts as potential vascular supplementary system and plays important role in the cerebral ischemia. Main body Collateral circulation has implications in the management especially related to cerebral endovascular treatment and thrombolytic therapy. It is considered as subsidiary network of vascular channels, which is highly variable. Insufficient arterial supply is due to the hemodynamic compromise because of thromboembolism. Apart from the collaterals, there is additional existence of a group of vessels known as venous collaterals. Their function is variable and they contribute to the augmentation of venous drainage in venous ischemias. Various pharmacological interventions are used to modulate the collaterals, these can prove to be a complementary alternative to the invasive intracerebral interventions. Conclusions The aim of this review article is to highlight the importance of cerebral collateral circulation and to discuss the various available pharmacological alternatives available and their current relevance in the management of various neurovascular pathologies.

Subsidiary initiatives of multinationals face both environmental and local conflicts

Purpose The research was governed by the following questions: 1. What opportunities and conflicts do subsidiary initiatives create in HQ-subsidiary relationships? 2. How does the MNC subsidiary network stifle or oppose subsidiary initiatives, and what role does HQ play in this process? 3. Does the subsidiary’s operating environment generate obstacles to new initiatives? 4. What factors moderate subsidiary initiative conflict in the MNC network? Design/methodology/approach The authors reviewed publications focusing on subsidiary initiatives from four leading databases – JSTOR, EBSCO, Google Scholar and Science Direct. They chose 52 papers for analysis of HQ-subsidiary issues. They chose an additional 62 publications that related to local environmental pressures that hindered subsidiaries. They narrowed their focus to emerging markets such as Nigeria Findings For subsidiary initiatives to do well, it’s essential to attract the “attention or interest” of HQ. But HQ pays attention only if it sees how the local plans will contribute to the corporation's overall interests. The corporate immune system (CIS) may become a major obstacle. It usually arises when CIS conflict triggers intra-firm competition over similar products between rival subsidiaries. However, if HQ perceives a subsidiary as having superior strategy it will be supportive of its initiatives. Originality/value Previous studies had focused on internal issues at the multinationals, whereas the authors wanted to study also the environmental obstacles to subsidiary initiatives

Subsidiary Networks and Foreign Subsidiary Performance: A Coopetition Perspective

ABSTRACTFrom a coopetition perspective, we differentiate between a multinational enterprise's product-similar subsidiary network and product-different subsidiary network in a host country. We argue that the product-similar network will have a curvilinear (inverted U-shaped) effect on foreign subsidiary performance, whereas the product-different network will produce a monotonic (positive) effect. Moreover, we introduce host-country economic advantage and intangible resource of the subsidiary as moderators into the relationship between subsidiary network and performance. Using longitudinal panel data of foreign subsidiaries, we find evidence that when host-country economic advantage is large, and the level of intangible asset intensity is high, the inverted U-shaped effect of product-similar subsidiary network is less pronounced. Moreover, host-country economic advantage and intangible asset intensity both enhance the positive effect of product-different subsidiary network. However, the moderating effect of intangible asset intensity is opposite to our prediction.