[sci.bio] What is mechanism for bloating of bodies after death?

steve%revolver@gatech.edu (12/09/89)

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     A question has arisen on one or two other newsgroups recently whose
answer may be provided here.  It involves the decomposition of a human
body after death.

     What is the mechanism which causes the bloating which is observed shortly
after death?  I think it involves anaerobic bacteria, but why do these same
bacteria not cause bloating when the person is alive.  What has changed after
death (beyond the obvious) that was not happening when the person was alive.
How is the rate of decomposition affected by temperature?  Please be as specific
as you possibly can.

***    The preceding statements represent the opinions of the author.   ***
       They must not be interpreted as representing the beliefs of any
       other person, institution, government agency, or business entity.            

scb1@tank.uchicago.edu (Sam Blackman) (12/09/89)

In article <4246@hydra.gatech.EDU> steve%revolver@gatech.edu writes:
>
>     What is the mechanism which causes the bloating which is observed shortly
>after death?  I think it involves anaerobic bacteria, but why do these same
>bacteria not cause bloating when the person is alive.  What has changed after
>death (beyond the obvious) that was not happening when the person was alive.

What has changed, in fact, is the fact that the person no longer has an
immune system that is capable of eliminating these bacteria because, of course,
he is now dead.  Similarly, there is a host of E. Coli and other bacteria
that live in our GI tract that will continue to function once we have
expired.  Perhaps it is these bacteria that are producing, amongst other
things, carbon dioxide, methane, etc.  thus the bloating.


-- 
Samuel C. Blackman        ! InterNet : scb1@tank.uchicago.edu   Link : UG0184
University of Chicago     ! Disclaimer : Who cares what I say? I'm a student !
5319 S. Maryland Ave. #2  ! Quote : "Changing the world one person at a time"
Chicago, IL 60615         ! Phone : (312) 715-3100 x.60 (w) (312) 947-8652 (h)

rwright@novavax.UUCP (Ronald K. Wright) (12/10/89)

steve%revolver@gatech.edu writes:

>xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

>     A question has arisen on one or two other newsgroups recently whose
>answer may be provided here.  It involves the decomposition of a human
>body after death.

>     What is the mechanism which causes the bloating which is observed shortly
>after death?  I think it involves anaerobic bacteria, but why do these same
>bacteria not cause bloating when the person is alive.  What has changed after
>death (beyond the obvious) that was not happening when the person was alive.
>How is the rate of decomposition affected by temperature?  Please be as specific
>as you possibly can.

Bloating of the body is caused by anaerobic bacterial growth.
Generally, at around 25 degrees C it occurs on the third day after
death.  At 20 degrees on the fourth. At 0 degrees it never occurs.

The anaerobes are the ones which live in your gut (and mine).  In
life, our wonderful gut keeps them in.  Die and they migrate via the
blood to inhabit the entire body.  As they grow they release gasses
including methane, and some foul smelling guys called putricine and
cadavarine.

Temperature speeds up decomp.  In south Florida waters the summer
temperatures are 30-32 degrees.  At this temperature a body floats at
24 hours after death.  Floating is caused by the gas.

Disease, particularly sepsis speeds up decomp both from the terminal
fever which warms the body and also because the organisms causing the
sepsis are already out in the blood stream.  Stillborn babies never
bloat as they have sterile guts.  Folk who take tetracyclines or other
broad spectrum antibiotics bloat very very slowly as much of the
normal gut flora is killed.


-- 
R. K. Wright MD JD                     | office: uunet!medex2!medexam!rkw
Chief Medical Examiner, Broward County | nova:   novavax!rwright
Associate Professor Pathology          | home:   uunet!medex2!love1!rkw
University of Miami School of Medicine | fax:    305 765 5193

richard@gryphon.COM (Richard Sexton) (12/11/89)

Herr Doktor Professor Emeritus Gyne Ward Smyth asked me to post this
to continue the fine tradition of pure scientific thought in the
USENET sci hierarchy:

In article <4246@hydra.gatech.EDU> steve%revolver@gatech.edu writes:
>xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
>
>     A question has arisen on one or two other newsgroups recently whose
>answer may be provided here.  It involves the decomposition of a human
>body after death.
>
>     What is the mechanism which causes the bloating which is observed shortly
>after death?  I think it involves anaerobic bacteria, but why do these same
>bacteria not cause bloating when the person is alive.  What has changed after
>death (beyond the obvious) that was not happening when the person was alive.
>How is the rate of decomposition affected by temperature?  Please be as specific
>as you possibly can.

Science has a theory for this which depends on the as yet unproven
existence of ``evil cells''. When a body dies, the evil cells (which
cause evil human behavior, and a few minor skin diseases) run rampant
as the bodies natural defenses are ``no longer active''. One of the
first things the evil cells do is go on holiday as they've been busy,
busy, little beavers. The preferred mode of transit
for the evil cells is little tiny hot air balloons. One of the biggest
problems in science today is where the balloons come from; traces
of them are usually very easy to detect in most humans. At any rate,
at the completion of the evil cells holiday, they leave and inhabit
some other body (Which often accounts for the mood shifts seen in
casual drug users. It is not the case that thay start using drugs
and then experience a mood swing, quite the opposite is true. They
are inhabited by evil cells, experience a mood shift, and soon thereafter
start using evil drugs) leaving behind the baloons. When the baloons
eventually deflate, the gas, which was generated from dead human tissue,
fills the body cavity.

							RJS
							"Either that or
							unchecked growth 
							of anaerobic bacteria"

larry@kitty.UUCP (Larry Lippman) (12/11/89)

In article <1670@novavax.UUCP>, rwright@novavax.UUCP (Ronald K. Wright) writes:
> >     What is the mechanism which causes bloating which is observed shortly
> >after death?  I think it involves anaerobic bacteria, but why do these same
> >bacteria not cause bloating when the person is alive.  What has changed after
> >death (beyond the obvious) that was not happening when the person was alive.
> 
> Bloating of the body is caused by anaerobic bacterial growth.

	The term "putrefaction" specifically refers to the decomposition of
proteins by anaerobic bacteria.

> The anaerobes are the ones which live in your gut (and mine).  In
> life, our wonderful gut keeps them in.  Die and they migrate via the
> blood to inhabit the entire body.  As they grow they release gasses
> including methane, and some foul smelling guys called putricine and
> cadavarine.

	In humans, the most common anaerobic bacteria responsible for
putrefaction is Clostridium welchii, which is abundantly found in the
colon.  Proteolysis of the intestinal wall following death facilitates
the rapid migration of Cl. welchii to the rest of the body.  The first
external sign of putrefaction is a greenish discoloration of the lower
abdominal wall, typically occurring between 1 to 3 days following death.
Temperature is unquestionably the most important factor in determining
this time interval.

	The following are some examples of chemical mechanisms which occur
during putrefaction:

1.	Simple amino acids, such as alanine, will form propionic acid by
	deamination, and ethylamine through decarboxylation.

2.	Some amino acids, such as tyrosine, have multiple mechanisms of
	deamination, decarboxylation, oxidation and reduction which
	entually produce an end product of phenol.

3.	The predominant gaseous end products of putrefaction - methane and
	hydrogen sulfide - are produced by simultaneous deamination and
	decarboxylation of cysteine, which then produces methyl mercaptan
	(methanethiol) as an intermediate product.  Methyl mercaptan, while
	not a gas, is extremely volatile and is one of the most odoriferous
	substances found in nature.

4.	Decarboxylation of lysine produces cadaverine (1,5-diaminopentane).

5.	Decarboxylation of ornithine produces putrescine (1,4-diaminobutane).
	A second mechanism for production of putrescine is facilitated by
	E. coli which cause decarboxylation of arginine; this mechanism
	also produces urea.

6.	Decarboxylation of histidine produces histamine.

7.	Tryptophan undergoes deamination to produce skatole (methyl indole),
	followed by indole itself.  Skatole and indole are responsible for
	producing the characteristic odor of feces.  Tryptophan also
	undergoes decarboxylation to form tryptamine.

	Detecting gaseous products of putrefaction, such as methane, hydrogen
sulfide and volatized methyl mercaptan, has been used as a means to locate
deceased victims in mass disasters.  Typically, a portable industrial gas
monitor with an air sampling probe is employed; the gas monitor device uses
a sensitive electrochemical or thermal conductivity detection element.

> Temperature speeds up decomp.  In south Florida waters the summer
> temperatures are 30-32 degrees.  At this temperature a body floats at
> 24 hours after death.  Floating is caused by the gas.

	While putrefaction as described above is the primary mechanism behind
the decomposition of a cadaver in water, other mechanisms exist, such as
digestion by algae, destruction by carnivorous marine life, and physical
damage by boat propellers, water intake pumps and hydroelectric turbines.

	In addition, starting only a few days after death (but not being
usually noticeable for some weeks), fats in a body undergo hydrolysis to
form a waxy substance called adipocere.  Adipocere requires an exposure to
water, and forms on the skin and subcutaneous fat first, while eventually
proceeding to within the body.  Adipocere is composed primarily of fatty
acids, whose formation then inhibits further bacterial putrefaction.  Note
the distinction between "putrefaction" and "decomposition", with the former
being but a subset of the latter.  Significant adipocere formation reduces
the specific gravity of a body, making it easier to float.

<> Larry Lippman @ Recognition Research Corp. - Uniquex Corp. - Viatran Corp.
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