Leptin is a hormone secreted by adipose tissue in direct proportion to amount of body fat. The circulating leptin levels serve as a gauge of energy stores, thereby directing the regulation of energy homeostasis, neuroendocrine function, and metabolism. Persons with congenital deficiency are obese, and treatment with leptin results in dramatic weight loss through decreased food intake and possible increased energy expenditure. However, most obese persons are resistant to the weight-reducing effects of leptin. Recent studies suggest that leptin is physiologically more important as an indicator of energy deficiency, rather than energy excess, and may mediate adaptation by driving increased food intake and directing neuroendocrine function to converse energy, such as inducing hypothalamic hypogonadism to prevent fertilization. Current studies investigate the role of leptin in weight-loss management because persons who have recently lost weight have relative leptin deficiency that may drive them to regain weight. Leptin deficiency is also evident in patients with diet- or exercise-induced hypothalamic amenorrhea and lipoatrophy. Replacement of leptin in physiologic doses restores ovulatory menstruation in women with hypothalamic amenorrhea and improves metabolic dysfunction in patients with lipoatrophy, including lipoatrophy associated with HIV or highly active antiretroviral therapy. The applications of leptin continue to grow and will hopefully soon be used therapeutically.

Recent studies have demonstrated that obesity is a significant risk factor for the development of several malignancies, but the mechanisms underlying this relationship remain to be fully elucidated. Adiponectin, an adipocyte secreted endogenous insulin sensitizer, appears to play an important role not only in glucose and lipid metabolism but also in the development and progression of several obesity-related malignancies. In this review, we present recent findings on the association of adiponectin with several malignancies as well as recent data on underlying molecular mechanisms that provide novel insights into the association between obesity and cancer risk. We also identify important research questions that remain unanswered.

Background-Transesophageal echocardiogram (TEE) is considered the gold standard modality in detecting left atrial/ LA appendage (LA/LAA) thrombi. However, this is a semi-invasive procedure with rare but potential life-threatening complications. Cardiac computed tomography has been proposed as an alternative method. The purpose of this metaanalysis was to evaluate the diagnostic accuracy of cardiac computed tomography assessing LA/LAA thrombi in comparison with TEE. Methods and Results-A systematic review of Medline, Cochrane, and Embase to look for clinical trials assessing detection of LA/LAA thrombi by cardiac computed tomography when compared with TEE in patients with a history of atrial fibrillation before electric cardioversion/pulmonary vein isolation or after cardioembolic cerebrovascular accident was performed using standard approach and bivariate analysis. Nineteen studies with 2955 patients (men, 71%; mean age, 61±4 years) fulfilled the inclusion criteria. Most studies (85%, 16 studies) used 64-slide multidetector computed tomography and 15 studies (79%) were electrocardiographic-gated. The incidence of LA/LAA thrombi was 8.9% (SD, ±7). The mean sensitivity and specificity were 96% and 92%, whereas the positive predictive value and negative predictive value were 41% and 99%, respectively. The diagnostic accuracy was 94%. In a subanalysis of studies in which delayed imaging was performed, the diagnostic accuracy significantly improved to a mean weighted sensitivity and specificity of 100% and 99%, respectively, whereas the positive predictive value and negative predictive value increased to 92% and 100%, respectively. The accuracy for this technique was 99%. Conclusions-Cardiac computed tomography, particularly when delayed imaging is performed, is a reliable alternative to TEE for the detection of LA/LAA thrombi/clot, avoiding the discomfort and risks associated with TEE.