A dose-response relationship with weight and fat loss was observed with subcutaneous recombinant leptin injections in both lean and obese subjects. Based on this study, administration of exogenous leptin appears to induce weight loss in some obese subjects with elevated endogenous serum leptin concentrations. Additional research into the potential role for leptin and related hormones in the treatment of human obesity is warranted.
Aims The aim of this study was to compare the effects of aspirin on platelet function as measured by the 'classical' template bleeding time with a new ex vivo method measuring closure times using the PFA-100@ machine. Platelet aggregation in response to arachidonic acid was also measured ex vivo. Methods The trial was a randomized, double-blind, placebo-controlled crossover design, with each volunteer taking 750 mg aspirin (BP) or placebo, three times a day for 5 days, with an 18 day wash-out period between treatments. Bleeding times and closure times were measured before the first dose on the first day and 0.5 h after the last dose on the fifth day of each treatment period. They were also measured 2 weeks after the last day of the trial. Results Baseline bleeding times ( pre-placebo) were 415 s using the Simplate, whilst baseline closure times were 115 s using the PFA-100@. Aspirin treatment caused an increase of both the template bleeding time (61%) and the closure time of the PFA-100@ (79%) when compared with the effects of placebo. The platelet aggregatory response to arachidonic acid was completely inhibited following aspirin treatment and was unaffected following placebo. Two weeks after the end of the trial, all values had returned to pre-treatment levels. The template bleeding time was unaltered in 1 of the 12 volunteers during aspirin treatment and was significantly prolonged in 3 of the 12 volunteers during placebo treatment. The PFA-100@ closure time was unaltered in 1 of the 12 volunteers during aspirin treatment and was prolonged in 1 subject during placebo treatment. Conclusions The change in closure time using the PFA-100@ is as sensitive and reproducible to the effects of aspirin on platelet function as is the template bleeding time test. However, the PFA-100@ produced less variable effects with fewer false positive results.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.