Carbon dioxide and other greenhouse gases (GHGs) are responsible for global warming, the long-term worldwide average warming experienced since the industrial revolution. GHGs arise from human use of fossil fuels for energy. Major emitters of GHGs include both industrialized countries and, in recent decades, developing countries as well. Higher global temperatures cause the extremes of hot and cold, and wet and dry, weather of recent years. This blog examines global warming and its effects.
See the Tabbed Pages for links to video tutorials, and a linked list of post titles grouped by topic.
This blog is expressly directed to readers who do not have strong training or backgrounds in science, with the intent of helping them grasp the underpinnings of this important issue. I'm going to present an ongoing series of posts that will develop various aspects of the science of global warming, its causes and possible methods for minimizing its advance and overcoming at least partially its detrimental effects.
Each post will begin with a capsule summary. It will then proceed with captioned sections to amplify and justify the statements and conclusions of the summary. I'll present images and tables where helpful to develop a point, since "a picture is worth a thousand words".
Saturday, July 15, 2017
Scientific Underpinnings of Modern Medicine - Vaccination
Our understanding of the human immune system made tremendous progress all
through the 20th century, continuing even to the present day.As part of this effort, important advances
have been made in vaccine development, saving millions of lives worldwide.But false reports linking vaccination with
autism have led to rejection of vaccination by many parents, who fear incorrectly
that vaccination may trigger the later appearance of autism.
can only proceed by open-ended inquiry, untainted by preconceived biases.Unscientific proposals that are counter to
the results of objective inquiry, such as the harmful movement to shun
vaccination, are unproductive.They harm
society at large by diverting attention and wasting resources.Human progress relies on critical
verification of scientific discovery, and on building further on the progress
Allison had married relatively late, and was happy
to have her infant son and husband as her family setting.
As a parent, she’s been aware of the controversy in
the popular press surrounding the question of a possible link between administering
vaccines to infants and the later development of autism.Having done considerable research on the
controversy during her pregnancy, Allison realized she needn’t have concerns
about this. She concluded that a possible connection with autism was mistaken. She
proceeded to give all the vaccines recommended for growing children to her son,
who continued growing to become a healthy child.
The modern practice of medicine
has benefited enormously from the results of scientific research in the
biological and medical sciences.We all are
better off from the results of these efforts.The previous post dealt with the discovery of the structure of DNA and
the genetic code, and the immune system.Here I discuss the immune system in
vaccination, and fallacies surrounding use of vaccination.
Antibodies.One of the ways that the immune system reacts
to, and fights against, a foreign (likely disease-causing) particle, such as a
virus, cell, or parasite, is to generate antibodies (a group of special protein
molecules) that specifically react against particular structures on the
particle (the antigen). The antibodies
bind molecule-to-molecule to the antigen, inactivating the particle (see the previous post)
and preventing the disease or minimizing its harmful effects.
Vaccines.Vaccination is another process involving the
immune system.It has long been used as
a way of deliberately confronting the immune system of a healthy person with a component
obtained from, or that is similar to, a foreign antigen that causes disease in
humans, in order to generate protective immunity against appearance of the
disease later on.The process was
originally developed by Edward Jenner in the 18th century for
preventing smallpox.It was known
anecdotally that milkmaids who contracted cowpox from infected cows rarely
became infected with smallpox.Cowpox
causes a similar, but weaker, illness in humans than smallpox.
Jenner’s scientific breakthrough was to take the
fluid produced in the cowpox infection, and to introduce it under the skin of healthy
people.He found that the treated people
did not develop smallpox.(We now
understand that his procedure induced the immune system to produce antibodies
that specifically attack the cowpox- or smallpox-causing substance, a
virus.A protein on the cowpox virus is
sufficiently like the corresponding protein on the smallpox virus that the
human antibodies that bind to cowpox also bind to smallpox, thus inactivating
Many vaccines have been developed since then to
immunize people against infection from viruses or bacteria.Today commercial vaccines contain a very
small amount of a preservative to keep them sterile.Most vaccination is for young infants and
toddlers, to protect against diseases such as diphtheria, whooping cough and
Vaccines and Autism.Public fear over use of vaccines has
developed over the past two decades. It started with an erroneous and
misleading report of a connection between vaccination and autism in
children. (See Science (2017), Vol.356, pp.364-373.)
In 1998 a physician, Andrew Wakefield, published a
report in a respected British medical journal suggesting that use of the
measles-mumps-rubella triple vaccine could lead to later development of autism.His report led to a 20% reduction in
vaccinations in Britain.But in 2004 a
journalist found that Wakefield was involved in trying to patent a competing
measles vaccine, which was a serious conflict of interest.The journal, in further investigations of its
own found serious ethics violations by Wakefield and retracted his original
paper in 2010.A short time later the
British General Medical Council revoked his license to practice medicine at all.Thus Wakefield’s original findings were
definitively determined to be invalid.
There is also a more general suspicion by many parents of an unwelcome intrusion by government authorities into a family’s health care decisions, as well as other nonscientific fears.
More recently, the Journal of the American Medical Association reported no difference
in rates of autism between vaccinated and unvaccinated children. (See Science, cited above.)
a mercury-based preservative, had been used in very small amounts in vaccines
until 2001, when its use was discontinued in almost all vaccine
compositions.Even so, four years later in
2005 the lawyer Robert F. Kennedy Jr. (late President John F. Kennedy’s nephew)
alleged in Rolling Stone and Salon that the U. S. government was hiding
evidence that use of thimerosal led to increased incidence of autism.The data Kennedy cited were mistaken, and in
2011 Salon retracted his
Both the U. S. Centers for Disease Control and
Prevention and the United Nations’ World Health Organization have concluded
that thimerosal causes no health problems in children. (See Science, cited above.)By contrast, a report published online in Natureon July 12, 2017 compares social interactions of infants and toddlers among
pairs of identical twins, pairs of fraternal twins, and paired but unrelated
single-birth infants and toddlers.A genetic
component was detected among children in the study that later were diagnosed with
autism but that was absent in normal children.This work shows that our scientific understanding of autism is growing
as rigorous investigation proceeds.
Public refusal of vaccination
places the children of rejecting parents in considerable danger because the
infections that the vaccines inhibit cause serious or fatal diseases.If enough children remain unvaccinated
contagion can spread the diseases among them.On the other hand, the World Health Organization estimates that 2 to 3
million lives a year are saved because of successful vaccination programs.
in biological and medical science, including immunology, have been made since
the end of World War II.Among these is
cancer immunotherapy, in which antibodies are created to antigens on cancer
cells, as if the cancers were foreign invaders like viruses and bacteria (see
the previous post).
Immunological research has also led to use of new,
effective vaccines, raising immunity to dangerous diseases in our bodies.To our detriment, nonscientific, indeed
antiscientific, campaigns against the use of vaccines in children have increased
the number of susceptible children among the populations of many developed
countries, including the U.S., potentially to dangerous levels.The spread of virulent infections is enabled
by the failure to vaccinate. (See Science,
Scientific investigation seeks to expand
our knowledge and understanding of the world we live
in.Reflecting on the state of knowledge
at any time, a curious scientist poses a question or suggests a
hypothesis.Experiments directed toward
answering the question or verifying the hypothesis are carried out as an
objective pursuit, further characterizing the natural world, without
introducing preconceived biases. Conclusions
are then drawn based on the new results obtained. These frequently lead to
practical applications that improve our health and prolong lives.