(-)-Menthol-d₄

Ca²⁺ staining is an experimental technique that utilizes specific fluorescent probes (such as Fluo-4 AM, Fura-2, etc.) to qualitatively or quantitatively detect dynamic changes in intracellular Ca²⁺ concentrations; this is achieved by monitoring the changes in fluorescent signals generated when these probes bind to free intracellular calcium ions. The underlying principle relies primarily on the presence of chelating groups within the probe's molecular structure that possess high affinity for calcium ions.

Subcutaneous cell-line-derived xenograft (CDX) models are established by implanting cultured human cancer cell lines into immunodeficient mice, where the injected cells form localized tumors that can be monitored in vivo as a measure of tumorigenic potential, growth kinetics, and treatment response. These models are widely used in oncology research because they allow reproducible tumor formation and enable comparative assessment of tumor growth between different cell lines or genetic manipulations in a controlled in vivo microenvironment. Subcutaneous implantation of cancer cells in immunodeficient mice is a standard approach for evaluating tumor growth behavior and therapeutic response across multiple cancer types, including prostate, esophageal, pancreatic, and colon cancer models.