Leptin physiology and pathophysiology in energy homeostasis, immune function, neuroendocrine regulation and bone health.

Since its discovery and over the past thirty years, extensive research has significantly expanded our understanding of leptin and its diverse roles in human physiology, pathophysiology and therapeutics. A prototypical adipokine initially identified for its critical function in appetite regulation and energy homeostasis, leptin has been revealed to also exert profound effects on the hypothalamic-pituitary-gonadal, thyroid, adrenal and growth hormone axis, differentially between animals and humans, as well as in regulating immune function. Beyond these roles, leptin plays a pivotal role in significantly affecting bone health by promoting bone formation and regulating bone metabolism both directly and indirectly through its neuroendocrine actions.

Thrombotic Thrombocytopenic Purpura Following Pfizer-BioNTech COVID-19 Vaccination in a Patient With Multiple Myeloma: Case Report and Literature Review.

The vaccines developed to prevent infection and mitigate morbidity and mortality in patients with COVID-19 demonstrated high efficacy in clinical trials but were associated with adverse events, most of which were mild and transient. However, some adverse events were rather serious, with grave prognoses. Of note, a few cases of autoimmune hematological conditions such as thrombotic thrombocytopenic purpura (TTP), immune thrombocytopenic purpura (ITP), and vaccine-induced immune thrombotic thrombocytopenia (VITT) were reported.

Mixed Epithelial Stromal Tumor of the Kidney With a Mesenteric Lymph Node: A Case Report and Literature Review.

Mixed epithelial and stromal tumor (MEST) of the kidney belongs to the broad spectrum of renal neoplasms, distinguished by their varying composition of stromal to epithelial components. The histopathological display of the biphasic growth pattern of mesenchymal and epithelial elements, often with estrogen and progesterone receptor positivity, clinches the diagnosis. It is typically benign, with low recurrence rates and excellent prognosis after surgical resection.