1. What anatomic differences are there in neoplastic cells as
compared to healthy cells that influences the progress of diagnosis and
treatment?
Malignant neoplasms have atypical cell structure, with abnormal
nuclear
divisions and chromosomes. It loses its differentiation or
resemblance to the cell of origin. They are not cohesive and there pattern of
growth is irregular. No capsule is formed and distinct separation from
surrounding tissues is difficult.
The changes in the cell
membrane have been implicated in the failure ofthe neoplastic cells to respond
to normal growth control mechanisms. Aberrant glycosylation produces abnormal
glycolipid and glycoprotein structures in the cell membrane. Theses changes
result in alterations of cellular adhesion and intercellular communication. The
alterations in adhesion and communication can lead to loss of contact
inhibition and neoplastic change. Normal cells respond to a crowded
environment, but neoplastic cells do not, because they have lost their ability
to either to receive or send the necessary information to stop growth.
In tumor cells, tight junctions are usually retained, but gap
junctions
are frequently reduced or absent. Cells that look and act like the
cell of origin are called well differentiated cells. All benign tumors are well
differentiated. Neoplasms that bear little or no resemblance to the tissue of
origin are called poorly differentiated cells. The lack of differentiation is
called anaplasia and is a key feature of malignant tumors.
2. What would the pharmacotherapeutic effects of a medication that
alters microtubules? What disease process would be treated with this
medication?
Vinblastine prevents microtubule assembly. Vinblastine is used as
an
anticancer drug. This drug has neurological side effects because
microtubules are needed for anterograde transport and retrograde transport of
the axoplasmic flow process which transports protein from the endoplasmic
reticulum and Golgi apparatus of the cell body to the synaptic knobs. If you
don't have micotubles you don't have nerve transmissions to synapses.
Submitted by the Spring 2001 Pathophysiology Class.