Biomedical Engineering Reference
In-Depth Information
In addition, the browser lists the Allowable Qualifiers for aggression that can be used to restrict or
limit search results. As defined on the MeSH site (
www.nlm.nih.gov/mesh/MBrowser.html
)
, these
qualifiers are:
CL (classification)
— Used for taxonomic or other systematic or hierarchical classification
systems.
l
DE (drug effects)
— Used with organs, regions, tissues, or organisms and physiological and
psychological processes for the effects of drugs and chemicals.
l
PH (physiology)
— Used with organs, tissues, and cells of uni- and multi-cellular organisms
for normal function. It is used also with biochemical substances, endogenously produced, for
their physiologic role.
l
PX (psychology)
— Used with non-psychiatric diseases, techniques, and named groups for
psychologic, psychiatric, psychosomatic, psychosocial, behavioral, and emotional aspects,
and with psychiatric disease for psychologic aspects; used also with animal terms for animal
behavior and psychology.
l
RE (radiation effects)
— Used for effects of ionizing and non-ionizing radiation upon living
organisms, organs and tissues, and their constituents, and upon physiologic processes. It
includes the effect of irradiation on drugs and chemicals.
l
The most relevant of these qualifiers for the researcher's work is probably drug effects (DE), to
identify articles that deal with the physical and psychological aspects of drugs and chemicals dealing
with aggression. In addition, articles dealing with radiation effects (RE) may also be relevant,
especially if the articles describe radiation-induced genetic mutations associated with aggression in
rats or primates.
With the relevant MeSH search terms and contexts defined, the next step would be to conduct an
online search of the biomedical literature dealing with aggression using the online bibliographic
database PubMed. The search on PubMed would likely return citations such as Antonio Moniz's
surgical removal of the frontal lobes of the brain to control aggressive behavior—a procedure for
which he won the Nobel prize in medicine in the late 1940s. The search would also reveal work on
twin studies in Denmark in the late 1980s that suggests aggressiveness is a personality trait with a
genetic component because twins raised apart have similar aggressiveness scores.
The PubMed search would also reveal work on attempting to identify the genetic basis for aggression
in other animals, including lobsters, rats, and fruit flies. For example, researchers at Harvard and the
University of Basel in Switzerland experimented with fruit flies to quantify aggressive behavior as a
function of genetic makeup. Pairs of fruit flies were allowed to fight over females and the genetic
profiles of the winners were studied for systematic differences among those of more submissive
losers. One difference noted in the study is that there are significant variations in levels of certain
neurotransmitters, including serotonin and dopamine, in the brains of the more aggressive
combatants. However, these studies leave many questions unanswered, such as the contribution of
physical strength or experience to winning a bout. As in human conflicts, the better fighter, not
necessarily the more aggressive fighter, may be victorious.
Armed with information on aggression from the medical literature, the researchers might hypothesize
that a new drug that moderates the production of serotonin in the brain may be useful in controlling
aggressive behavior. They establish a study using volunteers who have been screened according to
the Overt Aggression Scale and they use a battery of clinical studies to rule out non-genetic causes
for aggressive behavior. The clinical examination includes a general history and physical, with a
neurological examination, medication history, and mental status examination, as well as Chest X-ray,
EEG, MRI, and lumbar puncture. The objective of this testing is to identify patients in which abnormal
behavior might be due to causes such as head trauma, infection, or brain tumors. For example,
meningitis, an infection of the spinal fluid, can result in behavior consistent with aggression and
apprehension. Volunteers for the study would also be subject to standard laboratory tests, including
urine drug screening, blood-alcohol concentration, serum drug concentrations, and a thyroid profile
to screen for patients who are taking illicit drugs or who have metabolic diseases that could
