Wednesday, December 5, 2012

The Top 20 animals beneficial to the medical field


In today’s world, the common belief is that the studies of zoology and medicine are vastly different and separate entities.  Zoologists deal with the fuzzy and creepy, crawly organisms that live in the jungle and deserts of the world, while medicine is the resident of the laboratory and the hospital.  They rarely cross, usually only when a human is attacked by a carnivorous beast or is bitten by a poisonous snake or spider.  At least that is the common idea.  The truth, however, is vastly different, with the lines being blurred more and more every day.  As science improves and more discoveries are made, those organisms that we think are only useful in zoos or in classes have been instrumental in almost all important medical advancements of the past century and beyond.  What follows is a Top Twenty List of such organisms, without which many lives would have been lost and which are providing hope for a brighter and healthier tomorrow.
20. Guinea pig (Cavia porcellus)
The practice of calling someone a “guinea pig” in a study common-place today, but this distinction is well deserved.  The furry critters have been a significant test subject for several Noble prize-winning scientists and in countless medical discoveries (including aiding in testing the vaccine for polio, a potent antitoxin for diphtheria, an upper respiratory tract disease resistant to various types of antibiotics, along with many of the first discoveries of how phagocytes and immunity functioned).  


19. Rats (Rattus norvecus), mice (mus musculus)
Another laboratory standard, rats and mice have become the stereotypical research animal.  However, this is quite well deserved, as both organisms have been used for experimentation and testing that has led to vaccines and treatments for countless diseases (yellow fever vaccine, tumor producing viruses and cancer treatments, polio vaccine, cholesterol regulation).  Rats and mice have provided a model of the human body and a practical way of testing the impacts of diseases on the main body systems (endocrine, nervous, cardiovascular, muscular) for years, being affected by the same diseases as humans and showing how genes can be manipulated to alleviate these diseases.  
18. Domestic horses (ex. Equus ferus)
Most nonscientists believe that urine is just urine.  However, the urine of horses possesses an interesting quality- it contains forms of estrogen that can be mixed with other estrogen-like compounds to form a drug that acts as hormone replacement therapy in women.  This drug (called Premarin) is extracted from the urine of pregnant mares and has been shown to be effective at reducing the symptoms of menopause and the similar symptoms of women who have had a hysterectomy.  The drug has also been studied for reducing the risk of osteoporosis and the chances of heart disease in women.  However, the farms that are the main producers of this have come under fire from animal rights groups for keeping the mares in inhumane conditions, putting a blight on an otherwise beneficial advancement. 
17. Hard shell clams (ex. Mercenaria mercenaria)
While clams are not known other than being omnipresent on every sea food menu of all time, clams were the perfect creature to test a medical innovation that has saved countless lives- the Magnetic Resonance Imaging (MRI) scan.  While Paul Lauterbur had completed the mathematical formulas for creating images with MRI, he still had viable way to test the discovery on a living creature, as his apparatus was too small for a rat or human.  However, a clam worked just fine, and with a successful scan of clams from nearby Long Island Sound, a new and improved MRI scan became available for the viewing of the brain and cancer, among other diseases.
16. Atlantic squid (Loligo pealei)
The brain is a complex organ, filled with nerves relaying impulses to all regions of the body.  The mechanisms controlling this phenomenon puzzled scientists for years.  That is until Thomas Huxley and Alan Hodgkin studied nerves of this organism, and developed a hypothesis for nerve impulses.  Using the giant axons of the squid, nerves were discovered to possess electrically charged ions, and the shifting of these ions in the nerve caused the impulses necessary for action.  This discovery led to new breakthroughs in neuroscience and a greater understanding of  muscle function, with electrotherapy for injuries and also using pacemakers to regulate heartbeat and defibrillators to restart the heart through an electrical charge mimicking the pulses.
15. Blow flies (ex. Lucilia sericata, L. illustris. Phormia regina)
In the surgical camps of World War I, soldiers coming in with gangrenous wounds normally were in so bad shape they could not be saved or would lose whatever body part in which they were wounded, but a startling discovery helped reverse this.  Wounds filled with maggots of the blow fly were often cleaner and less infected than non-infested wounds, leading to a new medical practice- maggot therapy.  While disgusting to think of for many people, maggot therapy leads to great possibilities for the treatment of infections resistant to antibiotics, including treating infected ulcers on the feet of diabetes patients and also MRSA sores on the body.  This innovation has saved numerous lives and limbs for patients where surgery was not an option.
14. Frogs (ex. Hyperolius mariae)
Frogs are well-known as bioindicators for the environment, being the first organisms hit in a polluted ecosystem.  As amphibians, a frogs skin depends on a moist environment to remain healthy, and because this skin is thin for the diffusion of moisture, pollutants can devastate frog species rather quickly.  This fact has led to many studies testing the effects of chemicals, including pesticides, medications, and industrial and sewage runoff, along with many others, on the environment.  One of the most famous studies in the last few years was the atrazine research of Dr. Tyrone Hayes, proving the compound was extremely detrimental to frog species, causing them to develop eggs in testes, and leading to the subsequent ban of the compound in Europe.  Frogs are the first responders to an environmental threat.
13. Fruit fly (Drosphila melanogaster)
The common fruit fly is well-known for expanding modern scientists understanding of genetics, with almost sixty-one percent of disease genes found in humans have a similar match in the fruit fly.  This fact (along with the ability for multiple generations to be formed rather quickly) allows fruit flies to be good substitutes for humans in the study of disease and how the diseases could possibly affect them.  As artificial humans, fruit flies have been used for many scientific breakthroughs in the past several years (including the study of genetic control during embryonic development, and also a greater understanding of the human olfactory receptor function). 

 
12. Sea slugs (Aplysia californica)
The sea slug has helped neuroscientists to learn more about the function of neurons than almost any organism.  The 2000 Nobel prize in medicine and physiology was awarded to Dr. Eric Kandel for his work on the differences between short and long term memory and how information is stored in the nervous systems of these organisms and the similarities to the human storage process.  Many insights into synaptic plasticity and the effects of synaptic plasticity have also been made studying the sea slug nervous system.  The main importance of the organism is the study of how dopamine affects synaptic transmission for muscle movement in neurons, which could lead to a cure for Parkinson’s disease if the mechanisms can be isolated.

 
11. Gila monster (Heloderma suspectum)
Diabetes, especially Type-2 diabetes, is becoming more and more common in the world today, especially in children and older adults who develop the disease over time or are born with the disease.  But relief may be possible through the saliva of a common Southwestern reptile- the Gila monster.  The saliva in the reptile produces a glucagon-like polypeptide that improves glucose homeostasis in diabetes patients.  This advancement could be used to create an insulin-aiding drug that would allow diabetes patients to balance their glucose levels and eliminate the dangerous spikes that lead to comas and problems circulation and vision, giving diabetes patients more freedom. 

 
10. Pigs (ex. Sus scrofa domestica)
With anatomy and physiology similar to that of a human, pigs have been invaluable assets to medical studies of serious diseases, including cystic fibrosis and retinitis pigmentosa (a degenerative retina disease where the rods and cones of the retina die causing impaired vision) and how the body would respond to treatment.  Pigs serve as quite accurate models and have been instrumental in many breakthroughs, including how peptides are produced in the brain and the development of the CAT (computer assisted tomography scan) scan for creating pictures of internal body ailments such as a cardiac infarction (heart attack) and cancer.  The full potential of pigs is more than likely nowhere close to being fully reached.

 
9. Zebrafish (Danio rerio)
Zebrafish are a species of fish common to the freshwater streams near the Himalayas, and possess organ development similar to that of humans, allowing them to serve as effective models for how disease will affect humans, but this is not their most substantial contribution to medicine.  Zebrafish possess rapid regenerative abilities that function similarly to the way embryonic stem cells function in humans.  This allows a zebrafish to activate the necessary genes for replicating a new limb with no scar or noticeable differences.  With the controversy surrounding stem cell research from aborted fetuses, the possible alternative of using zebrafish opens a new realm of possibilities.  If the necessary genes can be isolated and replicated, they could be inserted into the genetics of a human, allowing them to physically regrow a lost limb or organ.  Military amputees, accident victims, or cancer survivors could all benefit from this possibility, all stemming from the tiny zebrafish.  

 
8. Chimpanzees (ex. Pan trogodytes)
Chimpanzees are rapidly disappearing from many African countries, as hunting and habitat loss have taken a massive toll on the populations.  This is distressing for the loss of a species diversity in an important area of the world, but most importantly for the fact that chimpanzees may hold the key to eradicating HIV.  Chimpanzees and other similar apes develop a disease called SIV (Simian Immunodeficiency Disorder) that is analogous to HIV.  An interesting note is a common theory is SIV mutated and crossed species barriers to humans, becoming HIV-1 and HIV-2, the most common strains of the virus.  Testing on infected chimpanzees could hold the key to solving the global crisis of HIV, and hopefully produce a cure to eventually eradicate the virus altogether.  

 
7. Leeches (Hirudo medicinalis)
 Leeches have been used for centuries in medical procedures.  This is mainly due to one simple fact- they work well at what they do.  Leeches possess an anticoagulant in their saliva called hirudin that is an effective blood thinner, and if the anticoagulant could be synthesized in large amounts, it could be used as a high blood pressure medication, as a hemorrhoid cure, or to reduce the severity of contusions in regions of high blood flow.  Leeches are also instrumental in the success of skin transplants, where the leeches break up clots that impede the joining of the skin grafts to the body surface.  If a drug could be synthesized from leeches to accomplish this task, then a simple IV drip could keep a skin graft or even limb re-attachments from being rejected.

 
6. Rhesus macaque (Macaca mulatta)
Along with insights into human behavior and cloning, the commonly known Rhesus monkey has provided an important insight into human blood.  The most notable of these is the presence of an Rh factor in the blood of both the monkey and humans.  Indicated by Rh+ if the factor is present and by Rh- if the factor is not present, the determination of this factor has allowed for the success rate of transfusions and organ transplants to skyrocket.  Previously, blood was indicated by only the A, B, AB, O scale, and rejections of blood were common and frustrated doctors.  With the discovery of the Rh factor, blood can be more accurately matched, improving the success rate of a potentially life-saving procedure.  

 
5. Malayan pit viper (Calloselasma rhodostoma)
Cardiac infarctions are caused by blood flow to a region of the heart becoming blocked off, leading to a lack of oxygen and nutrients to the affected area and the subsequent death of the surrounding tissue.  These occurrences are often deadly and affect numerous people all over the world.  But there is hope in the form of a substance extracted from the venom of the Malayan pit viper- kistrin.  Kistrin functions as a blood thinner and an anticoagulant, beneficial to a viper trying to capture prey, but could be life-saving for a heart attack victim.  Kistrin is also concentrated enough that it can be used in specific areas without it spreading to other areas, allowing clots in the heart to be broken up without potentially threatening necessary clots elsewhere in the body, like for healing surgeries.  With kistrin, a heart attack “cure” is possibly within reach.

 
4. Vampire bat (Desmodus rotundus)
Similar to kistrin from the venom of the Malayan pit viper, the saliva of the vampire bat holds vast potential for the breakup of clots, particularly stroke inducing brain clots.  The saliva contains an enzyme called desmoteplase (DSPA) that is anticoagulant and allows blood to flow more freely.  This enables the vampire bat to feed more without having to bite prey again, but would allow humans to prevent strokes.  By breaking up clots, the partial paralysis or even death from a stroke can be avoided through a simple medication.  The DSPA has also been synthesized into a drug currently undergoing clinical trials, ironically called Draculin, which could be available for use sometime in the near future.   

 
3. Sponge (ex. Axinella cannabina, Acanthella klethra)
Seemingly doing nothing in marine habitats, other than filter feeding, sponges are actually secret life savers- they produce several compounds (including axisonitrile-1, and the various isonitrile and isothiocyanate variations) that are highly antimalarial, reacting to kill the Plasmodium parasite responsible for infecting humans, while still being safe for humans, especially pregnant women.  With malaria being one of the deadliest diseases in the world, with over 300,000,000 people being affected annually and over one million of these dying, a human-safe cure for malaria would instantly improve the quality of life for a massive portion of the globe.  While these products are still in testing for safety and effectiveness, further study could lead to more advances and synthesis.  If antimalarial compounds exist and can be isolated, it is reasonable to believe there are more secrets being hidden in these mysterious, simple organisms.

 
2. Sharks (ex. Squalus acanthias)
Shark cartilage has an interesting quality- if cancer cells form within the cartilage, the cancer will not spread far, and is eliminated from the cartilage.  This interesting adaptation has led to much research with shark cartilage, resulting in polypeptides with anti-angiogenic activity and amniosterols from liver isolations that are antibiotics for both Gram-positive and Gram-negative bacteria, along with exhibiting anti-angiogenic and anti-tumor properties.  In clinical trials now for the treatment of advanced non-small lung cancer, the possibilities of these discoveries are phenomenal.  If compounds can be isolated from the cartilage to combat various types of cancer cells, cancer research would jump forward at an astounding rate, allowing for more effective treatment and much higher survival rates and a decreased chance of relapse.  On an even grander scale, if the genes responsible for cartilage developing anticancer defense mechanisms or for the synthesis of the compounds could be found and then artificially implanted within humans, the body would be able to naturally fight off cancer like fighting off the common cold.  The possibilities are endless with the right research.

 
1. Spiders ( ex. Black widow- Latrodectus genus, Funnel web spider- Atrax genus, Brazilian wandering spider- Phoneutria genus, Chilean tarantula- Grammostola spatulata)
Spiders are often the subject of pathological fears and the first organism to be killed when seen, but these creepy organisms hold nearly limitless potential.  Spider venom is a highly developed neurotoxin with numerous health benefits.  Female Black widow spider venom contains a peptide that helps in the building of protein, which could be used to treat Alzheimer’s patients.  The venom of the Funnel web spider is currently being researched as a possible pain medication.  The Brazilian wandering spider has a compound that could possibly remedy erectile dysfunction.  The Chilean tarantula has venom that blocks ion channels in cells and prevents them from swelling, which is being used as a possible preventative for atrial fibrillation.  Spider venom may also be able to limit stroke damage.  And these are just a few of the thousands of species of spiders that exist.  If each one could provide a benefit to humans on a similar magnitude, spiders would become the newest scientific celebrity.  However, like many organisms on this list, they are being threatened by habitat loss and pollution to where species diversity could be extremely limited in the future and numerous species may be wiped out before they can be utilized.  Spiders are clearly the unsung, ungratified medical distributors in science. 

Amazing isn’t it?  Organisms many people refuse to even look at due to an unconscious fear are actually the greatest life-savers in the world.  The possibilities for new techniques, drugs, and therapies are endless and absolutely mind-boggling.  Think of all of the lives that could be changed through the eradication of cancer, HIV, and malaria.  The entire world would change through these advancements, giving many developing and struggling countries the rare chance to regain their footing in the world and begin to prosper.  The economic benefits would also be nothing to scoff at, with pharmaceutical companies having new drugs to sell that could actually be marketed cheaply and effectively (some of the aforementioned anticoagulant drugs from spider and Malayan pit viper venom having the possibility of being the same price as an aspirin) as miracle drugs, leading to a tidy profit.  This should have companies sending biologists to the field in droves, but unfortunately this is not the case.  All over the world, organisms holding the key to illnesses and advancements to benefit humanity are being wiped out before even being discovered, as habitat loss for urban development and farming and rampaging pollution drive the organisms over the edge without so much as a whimper to mark their end.  Species diversity is slowly developing inoperable internal wounds that will lead to a full collapse in the future.  Unless immediate conservation efforts are taken, soon the world will become nothing more than a shell of its former self, with humans being nothing more than disease ravaged, weakened shells.  But this will not come to be if the benefits, medical or otherwise, of the wide-range of organisms throughout the biosphere are found and utilized, before it is too late.