Аннотация
The article highlights that young animals with TB were administered isoniazid (manufactured by McLeods Pharmaceuticals, India) as a means to promote alterations in the path morphology and ultrastructure of parenchymal organs in calves and guinea pigs, specifically the liver, lymph, and kidneys. These changes were examined using a modern electron microscope device, which encompassed both scanning and transmission microscopy techniques. The data obtained from various measurements (µm) were presented for analysis. For histological and ultrastructural investigations, a method involving the creation of hysteresis using epoxies resin. Pathomorphological and ultrastructural changes encompass increased capillary permeability in lymph nodes, the presence of fat droplets with varying shapes and nuclear condensation of liver cells, diverse processes of dystrophy, and the appearance of fat droplets resembling "balls" in liver. Observed changes of the disintegration of nuclei within cells. These studies allow for the determination of the extent of morphological and structural changes in the animals' bodies, assessment of the level of changes, confirmation of effectiveness, and the development of optimal therapeutic protocols, such as sequential medication.