Masson's Trichrome Stain of ResidualAfter treatment of a Her2+ mammary tumor in a mouse, the tumor almost completely regresses. A small number of cells can survive therapy and lay dormant in the mouse mammary gland. These cells are called a residual lesion, as they resemble a lesion or scar in the mammary gland. Masson's trichrome stain shows the different cell types and supportive tissue in the residual lesion (cells are pink, collagen is blue, muscle cells are red).
Sparks of ThoughtBrain cells, called neurons, constantly act on and react to each other using chemical and electrical signals. Here we see neurons in a mouse brain extending the delicate cellular protrusions that mediate these actions and reactions. These protrusions are called axons and dendrites, respectively. The energetic dance across axons and dendrites shapes our brains, our thoughts, and our memories.
The Mutagenic Journey of Top2Since DNA undergoes complex changes throughout the cell cycle, it’s not surprising issues can arise. DNA strands can become interlocked, which is known as a DNA catenane, which can be detrimental to the cell. The enzyme topoisomerase 2 (Top2) reacts to the linked DNA molecules and attempts to resolve the catenane by causing a double strand break. If Top2 becomes trapped on the DNA strand after the break occurs, it can lead to mutagenic outcomes such as de novo duplications.