There are multiple definitions:

1. orthotopic heart transplantation(English)

   • HHT, HTX
   • Cardiology, Transplantation

2. 4-hydroxytamoxifen(English)

   • a metabolite of the antiestrogen, tamoxifen, in humans and other mammals
   • NF-kappa-B, OHTR, PKD3, TRIM
   • Estrogen, Hormone
   • https://doi.org…pnas.2100784118