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Case Studies

Every marine mammal patient we treat provides a never-before-seen glimpse into human medical conditions.


“Superstition” was an adult female California sea lion admitted to The Marine Mammal Center on Friday May 13, 2011. This animal was originally found on a beach in Half Moon Bay acting oddly, lethargic and not responding as a healthy female pinniped should. Upon physical examination and initial blood work, the Center's veterinarians discovered a firm mass in the pelvic region, some swelling around the perineum (the soft tissues around the anus) and there were indications that the kidneys were not functioning well.  Veterinarians suspected cancer. A follow up examination confirmed it and revealed multiple masses throughout the abdomen.

Sonogram of Superstition reveals cancer.
© The Marine Mammal Center

Yearly, about 17% of the adult sea lions (both males and females), that present for post-mortem examination to the Center, have developed this type of cancer late in their lives. There are at least three things associated with the development of this cancer, but like many cancers, the exact cause appears to be complex and is not completely understood. There is a virus involved, there are contaminants (pollution) involved, and there appears to be a genetic predisposition- but there may be more to the story. As a result, one of The Marine Mammal Center's largest research efforts is to gather complete sets of information, tissues, and other samples from as many of these animals as possible and get the same sets of information from an equal number of animals without cancer to compare and contrast. Veterinarians hope that these efforts will give a better understanding of how and why these animals develop this cancer and possibly lead to a discovery about the basic biology of all cancers - humans or pinniped! 

Samples of Superstition's brain tissue were collected immediately after euthanasia by one of the Center's collaborating research teams. The team is trying hard to establish tissue cultures of brain cells. Doing this allows research scientists to have live growing cells in special containers in the laboratory. They then have a ready supply of specific types of cells to conduct investigations at the molecular level. The team that received a donation from “Superstition” is particularly interested in cells from sea lion brains because they suspect sea lions have some unique ways of dealing with low oxygen levels.

Breath-holding marine mammals regularly experience blood oxygen levels low enough to cause humans to faint but they tolerate it just fine. The question is HOW?

“Superstition, © The Marine Mammal Center

If scientists can find out how, they might we be able to mimic it in conditions where low oxygen is a part of the disease like stroke, closed head injuries, and even prematurity in infants. 

Perhaps “Superstition” will contribute to a major breakthrough in cancer medicine, or our understanding of EEGs, or hypoxemia (low oxygen) therapies.


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