No abstract

Diabetes is now regarded as an epidemic, with the population of patients expected to rise to 380 million by 2025. Tragically, this will lead to approximately 4 million people around the world losing their sight from diabetic retinopathy, the leading cause of blindness in patients aged 20 to 74 years. The risk of development and progression of diabetic retinopathy is closely associated with the type and duration of diabetes, blood glucose, blood pressure, and possibly lipids. Although landmark cross-sectional studies have confirmed the strong relationship between chronic hyperglycaemia and the development and progression of diabetic retinopathy, the underlying mechanism of how hyperglycaemia causes retinal microvascular damage remains unclear. Continued research worldwide has focussed on understanding the pathogenic mechanisms with the ultimate goal to prevent DR. The aim of this paper is to introduce the multiple interconnecting biochemical pathways that have been proposed and tested as key contributors in the development of DR, namely, increased polyol pathway, activation of protein kinase C (PKC), increased expression of growth factors such as vascular endothelial growth factor (VEGF) and insulin-like growth factor-1 (IGF-1), haemodynamic changes, accelerated formation of advanced glycation endproducts (AGEs), oxidative stress, activation of the renin-angiotensin-aldosterone system (RAAS), and subclinical inflammation and capillary occlusion. New pharmacological therapies based on some of these underlying pathogenic mechanisms are also discussed.

H2S (hydrogen sulfide) is a well known and pungent gas recently discovered to be synthesized enzymatically in mammalian and human tissues. In a relatively short period of time, H2S has attracted substantial interest as an endogenous gaseous mediator and potential target for pharmacological manipulation. Studies in animals and humans have shown H2S to be involved in diverse physiological and pathophysiological processes, such as learning and memory, neurodegeneration, regulation of inflammation and blood pressure, and metabolism. However, research is limited by the lack of specific analytical and pharmacological tools which has led to considerable controversy in the literature. Commonly used inhibitors of endogenous H2S synthesis have been well known for decades to interact with other metabolic pathways or even generate NO (nitric oxide). Similarly, commonly used H2S donors release H2S far too quickly to be physiologically relevant, but may have therapeutic applications. In the present review, we discuss the enzymatic synthesis of H2S and its emerging importance as a mediator in physiology and pathology. We also critically discuss the suitability of proposed 'biomarkers' of H2S synthesis and metabolism, and highlight the complexities of the currently used pharmacological H2S 'donor' molecules and 'specific' H2S synthesis inhibitors in their application to studying the role of H2S in human disease.

Objective To examine the benefit of adding an internet-delivered behavior therapy to a buprenorphine medication program and voucher-based motivational incentives. Method A block-randomized, unblinded, parallel, 12-week treatment trial was conducted with 170 opioid-dependent adult patients (mean age 34.3 years; 54.1% male; 95.3% white). Participants received an internet-based community reinforcement approach intervention plus contingency management (CRA+) and buprenorphine, or contingency management alone (CM-alone) plus buprenorphine. The primary outcomes, measured over the course of treatment, were longest continuous abstinence, total abstinence, and days retained in treatment. Results Compared to those receiving CM-alone, CRA+ recipients exhibited on average 9.7 total days more of abstinence, 95% CI: (2.3, 17.2), and had a reduced hazard of dropping out of treatment, Hazard Ratio (HR)=0.47; 95% CI: (0.26, 0.85). Prior treatment for opioid dependence significantly moderated the additional improvement of CRA+ for longest continuous days of abstinence. Conclusions These results provide further evidence that an internet-based CRA+ treatment is efficacious and adds clinical benefits to a contingency management/medication based program for opioid dependence.