Mechanisms for the effects of fish oil lipid emulsions in the management of parenteral nutrition-associated liver disease.

Parenteral nutrition (PN) can be life saving for infants unable to adequately absorb enteral nutrients due to intestinal failure from inadequate bowel length or function. However, long-term PN carries significant morbidity and mortality, with 30 to 60% of patients developing progressive liver dysfunction. The etiology of PN-associated liver disease (PNALD) is poorly understood, however the involvement of lipid emulsions in its pathogenesis has been clearly established, with new emphasis emerging on the role of omega-6 polyunsaturated fatty acids and omega-3 polyunsaturated fatty acids. Recent studies evaluating the use of parenteral fish oil lipid emulsions instead of soybean oil lipid emulsions have demonstrated marked improvements in cholestasis, morbidity, and mortality in patients with PNALD treated with fish oil. This review provides an overview of the role of lipid emulsions in the pathogenesis of PNALD and the proposed mechanisms by which parenteral fish oil lipid emulsions may be exerting their beneficial effects.

Stroke of the posterior cerebral circulation.

AIM: Identification of stroke etiology aids in developing secondary prevention and treatment strategies for posterior circulation stroke (PCS). Studies have identified large vessel atherosclerotic disease as the predominant etiology and others have cited cardioembolism. This study was designed to describe the prevalence, outcome, and stroke mechanisms of PCS and to analyze the strengths and weaknesses of the classifications used. METHODS: A comprehensive MEDLINE search identified seven studies evaluating the etiology of PCS. Incoherent data and lack of prospective studies made performance of a thorough meta-analysis impossible. Special attention was paid to the design of trials and the classifications used. In a similar way, the limitations of each study were clearly determined. RESULTS: Seven trials encompassing 8057 patients, of which 23% were isolated PCS and 4% were combined ACS and PCS, were analyzed. Overall, large vessel atherosclerotic disease was responsible for 35% of PCS, cardioembolism for 18%, small vessel disease for 13% and undetermined etiology for 15%. Strokes of mixed and "other" etiology represented 4% and 8% of PCS respectively. Major sequelae were observed in 10.8-17.7% of patients with no sequelae noted in 7-28% of patients. Mortality ranged from 4-10% and it was directly related to stroke in 2-5%. CONCLUSION: Large vessel atherosclerotic disease was the most common stroke subtype identified. Conclusions are inconsistent between the studies, highlighting the difficulties in systematic investigations of stroke etiology and the need for a unified approach to stroke classification.