[ RadSafe ] teratogenesis can be pre-utero

[Rainer.Facius at dlr.de]

Gary and all,

to add some more relevant facts – relevant also with respect to radiation protection – to this somewhat confusing – or in part obfuscated – exchange:

Environmental toxins affect either cells of the soma or of the germ-line yielding somatic or genetic sequelae. Soma and germ-line constitute an exhaustive and mutually exclusive partition of the cells of higher metazoa. 

Somatic effects affect the exposed individual. Genetic effects are imprinted to the genome (possibly including the epi-genom) of germ-line cells and thereby become transmitted to the F1. Non-lethal, genetic effects accumulate in an exposed population leading to the – so far - about 3000 known hereditary diseases in humans. 

Effects to the progeny of exposures between conception and birth can be somatic and genetic again. Genetic effects in utero again become manifest not until the next, the F2, generation. 

Somatic effects to progeny of exposures in utero result in untoward outcomes such as stillbirth, premature birth, or teratogenesis (malformations) such as spina bifida or microencephaly. Teratogenesis, i.e., “ the disturbed growth processes involved in the production of a malformed neonate” results from irregular timing or incomplete sequences of organogenesis due to stimuli from the environment – which includes the maternal organism.

Addressing the business of radsafe by turning to ionizing radiation as an environmental toxin, the findings from the most important exposure of human populations, i.e., the survivors of the atomic bombings demonstrate that this so far most severe exposure did not yield any measurable genetic effect in the F1 generation. Concerning teratogenesis, fetuses exposed in a period between 8 to about 15 weeks after gestation showed few incidences of microencephaly as the only teratogenic sequela from the atomic bombing. Importantly, the corresponding dose effect relation – crudely as it could be determined – displayed the hallmark of deterministic radiation effects, i.e., a more or less marked dose threshold below which no effects will ensue. Given this empirical data base, the claim that radiation from depleted uranium can engender genetic or teratogenic health effects at the exposures in question must be relegated to the realm of science fiction. 

Regards, Rainer

Off topic: From the perspective of the conceptus/fetus the statistically largest environmental risk of irregular organogenesis and an untoward outcome of a pregnancy nowadays stems from the mental constitution of the maternal organism – in particular if the fetus carries two X chromosomes.

----Original Message-----
From: radsafe-bounces at radlab.nl on behalf of garyi at trinityphysics.com
Sent: Fri 30.05.2008 19:22
To: radsafelist
Subject: Re: [ RadSafe ] teratogenesis can be pre-utero
 
Statements like this show that James is not competent to debate this issue.  When you get 
caught with your pants down like this, especially when it is pointed out gently as Rainer has
done, the correct response is to admit the blunder.  Instead, James (whatever his name is 
right now) pretends to be absolutely correct.  

-Gary Isenhower

On 30 May 2008 at 6:34, James Salsman wrote:

> Dear Dr. Facius,
> 
> Thank you for your message:
> 
> >... teratogenesis by definition refers to effects
> > engendered IN UTERO....
> 
> On the contrary, any damage to spermatogonium, oogonium, oocyte,
> ootid, or ovum chromosomes prior to folliculogenesis may also result
> in congenital malformations.
> 


_______________________________________________
You are currently subscribed to the RadSafe mailing list

Before posting a message to RadSafe be sure to have read and understood the RadSafe rules. These can be found at: http://radlab.nl/radsafe/radsaferules.html

For information on how to subscribe or unsubscribe and other settings visit: http://radlab.nl/radsafe/