Freethought & Rationalism Archive

lpetrich · 10-24-2002, 08:50 PM

Vanderzyden has FINALLY noticed me. Thanx, O Vandie.

1. What life form isn't "constrained" by its biology? For that matter, what being isn't constrained by its nature? Humans aren't constrained. They rule the animal kingdom and the planet. How is that? They have MINDS. You and I have been over this ground before.

So there is some sort of mind-stuff that is lacking in the rest of the animal kingdom? O Vanderzyden, I suggest that you study chimpanzee behavior some time. If you think that chimps do not have minds, I'd be willing to learn your reasons.

2. OK, humans are more similar to chimps than fish. So? Despite our similarities, our physiology is still significantly different. And, again, you know that the sensibility of Darwinism is the subject of much debate.

Significantly different in what way? Be specific. I'd like to know what you have in mind.

3. No, comparitive embryology provides no extant support for Darwinism. It, too, is just one more "icon" of that belief system. Again, homology is not de facto evidence of common descent. There are other explanations that are categorically rejected by the Darwinist. (This point also addresses lpetrich's "data").

The only sensible form of creationism that could account for such features is pseudo-evolutionary creationism -- creationism that closely mimics descent with modification, something like an old-earth version of Philip Gosse's "Omphalos" hypothesis.

That is not an ABSOLUTE impossibility, but it is as pointless as Gosse's original hypothesis, that of a young earth created with an old-earth appearance.

Vanderzyden, I challenge you to account for early-embryonic circulation, multiple aortas and aortic arches and all, without resorting to pseudo-evolutionary creationism. And I mean by that something like

"The creator was too lazy to completely redesign the circulatory systems of land vertebrates so that they'd always be in land-animal configuration. So he/she/it made them develop like fish, then made them reorganize their blood vessels."

or

"The creator could not think of a good way to make jaws from scratch, so he/she/it induced the first gill bars in sequence to become jaws."

or

"The creator decided to make an early mammal's left systemic arch drop out and an early bird's right systemic arch drop out -- and then lazily copied those arrangements for all subsequent mammals and birds, without ever entertaining him/her/itself by creating some with the opposite systemic arch dropping out."

Rancid · 10-24-2002, 11:14 PM

Quote:

Originally posted by Vanderzyden:


But surely this is in error. I explicity stated a condition, preeclampsia, which shows clearly that there is a direct correlation between the fetal blood pressure and that of the mother. The mother's blood pressure does indeed contribute to the umbilical pressure.

Incorrect.

The mother and the fetus do not share blood, nor are their blood pressures linked.

If I remember correctly, preeclampsia is a pregnancy-related condition that causes high blood pressure (for the mother) and affects the mother's kidneys, liver, brain, and placenta. If untreated, preeclampsia may damage the mother's liver or kidneys, deprive the fetus of oxygen, and cause eclampsia (seizures). It does NOT affect fetal blood pressure or umbilical pressure.

scigirl · 10-24-2002, 11:27 PM

I have no idea what this has to do with the topic at hand, but here's what I found after doing a very extensive google search (ok it was the first hit...)

<a href="http://www.preeclampsia.org/about.asp" target="_blank">http://www.preeclampsia.org/about.asp</a>

Quote:

What is Preeclampsia?

Preeclampsia is a disorder that occurs only during pregnancy and affects both the mother and the unborn baby. Affecting at least 5 percent of all pregnancies, it is a rapidly progressive condition characterized by high blood pressure, swelling and protein in the urine. Sudden weight gain, headaches and changes in vision are important symptoms; however,some women with rapidly advancing disease report few symptoms.

Typically, preeclampsia occurs in the late 2nd or 3rd trimesters, (middle to late pregnancy), though earlier. Proper prenatal care is essential to diagnose and manage preeclampsia. Preeclampsia, Pregnancy Induced Hypertension (PIH) and toxemia are closely related conditions. HELLP Syndrome and eclampsia are more severe forms.

Preeclampsia and other hypertensive disorders of pregnancy are a leading global cause of maternal and infant illness and death. By conservative estimates, these disorders are responsible for 76,000 deaths each year.

Can I ask a dumb question? How is Vanderzyden going to use preeclampsia, which is obviously a design flaw which causes lots of pain and suffering, as evidence of perfect design of fetal circulation?

I don't get it. Am I just dense or something?

scigirl

scigirl · 10-24-2002, 11:57 PM

Just out of curiosity, I plugged in 'preeclampsia' and 'evolution' into my search and found some intriguing results:

<a href="http://www.naples.net/~nfn03605/dheapree.htm" target="_blank">Evidence of Ongoing Evolution: Evidence of Increasing Testosterone and the Increase in Preeclampsia </a>

Quote:

James Michael Howard:
This is intended to demonstrate that an ongoing, pathological phenomenon may be directly connected to my explanation of human evolution. That is, human evolution is directly influenced by levels of testosterone within populations. It is my hypothesis that testosterone is rising in society. More specifically, it is my hypothesis that the percentage of individuals who produce more testosterone is increasing compared to people who produce less. I suggest the increase in percentage of individuals of higher testosterone is identifiable as a change in children known as the "secular trend."
A secondary hypothesis suggests increased testosterone causes a number of problems within groups of higher testosterone. This may be occurring at this time. Among these problems may be an increase in a severe complication of pregnancy called preeclampsia. The Associated Press reported March 13, 2001, in: "Dangerous pregnancy complication on the rise," that preeclampsia is on the rise in the United States: "The NIH [National Institutes of Health] just sounded an alarm that the pre-eclampsia rate rose by nearly a third during the 1990s." The rise in the percentage of individuals of higher testosterone increases the fecundity of humans as well as specific characteristics of the hominid line. However, excessive amounts of testosterone produce characteristic negative phenomena within the hominid line and humans. This periodic cycling of high versus low levels of testosterone within populations has produced periodic shifts in hominid and human populations. Preeclampsia may be one of these negative consequences of excessive testosterone; the increase may represent a consequence of high levels of testosterone.
...
It is my hypothesis that testosterone is rising in society. More specifically, it is my hypothesis that the percentage of individuals who produce more testosterone is increasing compared to people who produce less. I suggest the increase in percentage of individuals of higher testosterone is identifiable as a change in children known as the "secular trend." The secular trend is the increase in height and weight and earlier puberty in children. (That is, children of higher testosterone are bigger and reach puberty earlier.) The secular trend is real and was recently documented in the United States (Freedman, D.S., et al., "Secular trends in height among children during 2 decades, The Bogalusa heart study," Archives of Pediatric and Adolescent Medicine 2000; 154:155-161).

Preeclampsia is increasing in the United States. I suggest this increase results from an increase in the percentage of women who produce increased levels of testosterone. Increased levels of testosterone may activate the "high activity genotype" of epoxide hydrolase in women of higher testosterone. This may account for the increase in preeclampsia.

Ok why is increased testosterone called the secular trend? Would an increase in estrogen be a religious trend? Very strange.

Here's another site:
<a href="http://www.cs.nsw.gov.au/Cardiovascular/renal/ini.htm" target="_blank">http://www.cs.nsw.gov.au/Cardiovascular/renal/ini.htm</a>

Quote:

Dr Annemarie Hennessy is coordinating an investigation of the pathogenesis of preeclampsia. Our research projects are designed to address the essential goal in preeclampsia; prediction of disease susceptibility by early pregnancy testing. The project is examining the role of placental pathology in maternal vasoconstriction and the contribution of the maternal tolerance of the foeto-placental unit to the development of the placenta. This study involves the use of molecular techniques and protein studies of pathophysiology in humans and also in a primate model of placental insufficiency. This unit has contributed significantly to understanding the mechanisms of normal physiological (particularly cardiovascular) adaptation to pregnancy in primates. Ongoing studies are examining the physiological consequences of alterations at the materno-placental interface.

Here's some more interesting articles on the subject from pubmed:
<a href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=119005 95&dopt=Abstract" target="_blank">Evolutionary adaptations to pre-eclampsia/eclampsia in humans: low fecundability rate, loss of oestrus, prohibitions of incest and systematic polyandry.</a>

Quote:

Gestational-hypertension/pre-eclampsia occurs in approximately 10% of human pregnancies. This persistent complication of pregnancy has been reported to occur more frequently in couples conceiving very shortly after the beginning of their sexual relationship and/or after a change in paternity. Primipaternity may be the leading cause of pre-eclampsia in women under 30 years of age when genetic susceptibility to cardio-vascular disease has not yet been expressed, especially in women before their twenties, who for the last 40,000 years have perhaps comprised the age group when the majority of parturients classified as Homo sapiens sapiens initiated their reproductive life. In terms of evolution, the prevalence of pre-eclampsia represents a distinct reproductive disadvantage in humans as compared with other mammals. Indeed, pre-eclampsia is a consequence of the defect of the normal human-specific deep endovascular invasion of the trophoblast. The large size of the human fetal brain imposing this deep trophoblastic invasion induced the need for major immunogenetic compromises in terms of paternal-maternal tissue tolerance. The price that mankind has had to pay to adapt to the pre-eclampsia risk is a low fecundability rate and therefore loss of oestrus, possibly a step in the deviation between apes and hominids. Further, pre-eclampsia risk may be a contributing factor leading to the rejection of systematic polyandry in human societies and have influenced prohibition of incest.

<a href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=941657 2&dopt=Abstract" target="_blank">Proteinuric hypertension in a pregnant baboon: was this pre-eclampsia?</a>

Quote:

We report the results of investigating a pregnant baboon that developed hypertension, proteinuria, and oedema in late gestation. Although the clinical presentation suggested a diagnosis of pre-eclampsia, the evolution of her clinical signs and results of a renal biopsy performed 3 weeks after delivery suggested that glomerulonephritis was the underlying disease.

scigirl

scigirl · 10-25-2002, 12:15 AM

Ok one more link...

since the topic of this thread is "fetal circulation," I thought we needed a good overview of the placenta (warning - there is a picture..."

scigirl

<a href="http://www.sccs.swarthmore.edu/users/98/amita/embryo.html" target="_blank">http://www.sccs.swarthmore.edu/users/98/amita/embryo.html</a>

Jack the Bodiless · 10-25-2002, 01:56 AM

Vanderzyden:

Quote:

You and I have had similar discussions, and you know that my concern is not damage to my vanity. Rather, I encourage efficiency and sensibility. My aim is to discover the truth about ultimate things. You should know me well enough now that I have no ulterior "ambitions" or "agenda".

On the contrary: we know you well enough to know that you are lying. That is evident to all, except possibly yourself. I am not sure if you realize it yet.

For instance:

Quote:

Scigirl,

Thank you for the offer to engage in yet another thread. I will pass, for now. I should also say that, on the face of it, the topic does not look very appealing since you are assuming trans-species evolutionary development of the heart. As you know, I do not agree with such assumptions, so there is no common ground from which we may begin (even if I did have time to engage in such a time-consuming journey).

It is evident from this that you do NOT seek to discover the truth about ultimate things: you refuse to even consider evolution, because it conflicts with your religious dogma.

I think the real issue here is: when will you admit to yourself that your mind is firmly closed, and that you simply don't want to seek the truth?

What, exactly, is the problem? What is holding you back?

As this issue isn't directly related to fetal circulation (but, nevertheless, very relevant to many of your responses on this thread), shall we discuss this elsewhere?

pz · 10-25-2002, 04:44 AM

Quote:

Originally posted by scigirl:
Just out of curiosity, I plugged in 'preeclampsia' and 'evolution' into my search and found some intriguing results:

<a href="http://www.naples.net/~nfn03605/dheapree.htm" target="_blank">Evidence of Ongoing Evolution: Evidence of Increasing Testosterone and the Increase in Preeclampsia </a>

Ah, the perils of the web...that's Howard's web site. He's a well-known net kook who frequently posts on sci.bio.evolution. His obsessive quirk is his claim that everything in evolution is the product of testosterone/DHEA. His "research" strategy is to comb the newspapers, magazines, online abstract databases, etc., and everything that even mentions testosterone or DHEA is seized upon as support for the all-pervasive, all-powerful influence of the magical steroids.

It was funny at first, but after a while it just gets really, really boring. And Howard is as thick as they come.

MrDarwin · 10-25-2002, 05:25 AM

Quote:

Originally posted by Vanderzyden:
2. OK, humans are more similar to chimps than fish. So? Despite our similarities, our physiology is still significantly different.

I would ask Vanderzyden for examples of such differences in our physiology, but I know it's probably useless. But for what it's worth, I'm unaware of any organ, gene, or biochemical pathway that is found in humans but not in chimps, or vice-versa.

MrDarwin · 10-25-2002, 05:44 AM

Quote:

Originally posted by Vanderzyden:
I explicity stated a condition, preeclampsia, which shows clearly that there is a direct correlation between the fetal blood pressure and that of the mother. The mother's blood pressure does indeed contribute to the umbilical pressure.

It shows nothing of the kind. I have not been able to verify this information from any websearch. Unfortunately, Vanderzyden has always proved remarkably unhelpful when we ask him to explain or back up things like this, if only to help educate us.

Quote:

Originally posted by Rancid:


Incorrect.

The mother and the fetus do not share blood, nor are their blood pressures linked.

If I remember correctly, preeclampsia is a pregnancy-related condition that causes high blood pressure (for the mother) and affects the mother's kidneys, liver, brain, and placenta. If untreated, preeclampsia may damage the mother's liver or kidneys, deprive the fetus of oxygen, and cause eclampsia (seizures). It does NOT affect fetal blood pressure or umbilical pressure.

This is pretty much what I found in my websearch. In numerous discussions of preeclampsia, I found no mention whatsoever of fetal blood pressure, or the blood pressure in the umbilical vessels, with regard to preeclampsia or with regard to maternal blood pressure.

Meanwhile, I have asked Vanderzyden several times how the supposedly high blood pressure is being generated in the umbilical vessels, because I really want to know. I'm not a doctor, I freely admit I am no expert on this topic. But when I get two answers, one from somebody who is a medical doctor with an intimate knowledge of human anatomy and physiology, and a different one from somebody who is not and has none, whose knowledge and expertise am I more likely to trust?

Vanderzyden · 10-25-2002, 11:23 AM

OK, folks. Let me just drop the positive umbilical pressure/preecclampsia contention. I had a misunderstanding about something in particular that I had read. Please accept my apologies for any inconveniences caused by my failure to research that example thoroughly enough.

However, my argument concerning pressure management remains largely intact. You will recall that I mentioned this at least once before. Simple laws of physics govern the pressure and velocity of fluids. So, if you take a positive, neutral or negative source and relocate it centrally in a circulatory system, the pressure map will change dramatically. Observe that we are not discussing capillaries here. We are talking about a trunk line, the umbilical vein. Rick and MrD suggest placing the umbilical juncture at the present location of the terminus of the ductus arteriosus. But, again, this is inherently problematic.

The management of fluid pressure becomes altogether different if you move the umbilical source from

(a) an UPSTREAM location, a LONG DISTANCE from and BELOW the heart

to a location

(b) that is DOWNSTREAM, immediately ADJACENT, and ABOVE the heart.

Such a design alternative means that the heart is now "pushing" instead of "pulling" on the blood that is coming through the umbilical vein. The heart would need to be enlarged significantly, and its valves reinforced. Even still, the design would be terribly poor. Why? Because the pump would not be in its proper location in this "alternative" design. Here is a simple diagram of the what MrD is suggesting:

> ------- PUMP ---- INFLUENT --- EFFLUENT --------> (to pump)

As you can see, there is nothing to pump. The system is grossly imbalanced. Both the influent (incoming flow from placenta) and the effluent (outgoing flow to placenta) are downstream of the pump.

There is another problem: another valve would need to be placed at this new junction so the blood isn't pumped back down the umbilical vein, which is at significantly LOWER PRESSURE. This would be very awkward, and certainly inelegant. Such a valve would need to have a strength comparable to the heart valves, since it would need to resist the high systemic pressure (in the aorta). We must wonder what type of tissue will be used to "construct" this valve, and what effects this will have on the adult circulatory system. This arrangement also introduces complications for the transition event, since the cut end of the umbilical vein is not (1) well below the level where its main flow enters the heart and (2) it's flow is not dampened by the liver.

I have yet to see anyone here refute this argument. Until someone does, then the sub-optimal design claim remains essentially without merit.

Other problems with the "alternative":

-- fetal development of the right side of the heart would be significantly reduced, since the right ventricle would not need to pump (nor could it pump against the high resistence of the pulomary veins)
-- inability to have a symmetrical, aesthetically pleasing location for the umbilicus
-- the heart itself would receive the least oxygenated blood, since the coronary arteries are located on the very end of this "improved" CV system

Again, I will list advantages of the ductus arteriosus:

� protects lungs against circulatory overload
� allows the right ventricle to strengthen
� hi pulmonary vascular resistance, low pulmonary blood flow

<a href="http://mcb.berkeley.edu/courses/mcb135e/fetal.html" target="_blank">http://mcb.berkeley.edu/courses/mcb135e/fetal.html</a>

John

[ October 25, 2002: Message edited by: Vanderzyden ]

[ October 25, 2002: Message edited by: Vanderzyden ]

10-25-2002, 11:23 AM	#150
Vanderzyden Senior Member Join Date: Jul 2002 Location: California Posts: 694	OK, folks. Let me just drop the positive umbilical pressure/preecclampsia contention. I had a misunderstanding about something in particular that I had read. Please accept my apologies for any inconveniences caused by my failure to research that example thoroughly enough. However, my argument concerning pressure management remains largely intact. You will recall that I mentioned this at least once before. Simple laws of physics govern the pressure and velocity of fluids. So, if you take a positive, neutral or negative source and relocate it centrally in a circulatory system, the pressure map will change dramatically. Observe that we are not discussing capillaries here. We are talking about a trunk line, the umbilical vein. Rick and MrD suggest placing the umbilical juncture at the present location of the terminus of the ductus arteriosus. But, again, this is inherently problematic. The management of fluid pressure becomes altogether different if you move the umbilical source from (a) an UPSTREAM location, a LONG DISTANCE from and BELOW the heart to a location (b) that is DOWNSTREAM, immediately ADJACENT, and ABOVE the heart. Such a design alternative means that the heart is now "pushing" instead of "pulling" on the blood that is coming through the umbilical vein. The heart would need to be enlarged significantly, and its valves reinforced. Even still, the design would be terribly poor. Why? Because the pump would not be in its proper location in this "alternative" design. Here is a simple diagram of the what MrD is suggesting: > ------- PUMP ---- INFLUENT --- EFFLUENT --------> (to pump) As you can see, there is nothing to pump. The system is grossly imbalanced. Both the influent (incoming flow from placenta) and the effluent (outgoing flow to placenta) are downstream of the pump. There is another problem: another valve would need to be placed at this new junction so the blood isn't pumped back down the umbilical vein, which is at significantly LOWER PRESSURE. This would be very awkward, and certainly inelegant. Such a valve would need to have a strength comparable to the heart valves, since it would need to resist the high systemic pressure (in the aorta). We must wonder what type of tissue will be used to "construct" this valve, and what effects this will have on the adult circulatory system. This arrangement also introduces complications for the transition event, since the cut end of the umbilical vein is not (1) well below the level where its main flow enters the heart and (2) it's flow is not dampened by the liver. I have yet to see anyone here refute this argument. Until someone does, then the sub-optimal design claim remains essentially without merit. Other problems with the "alternative": -- fetal development of the right side of the heart would be significantly reduced, since the right ventricle would not need to pump (nor could it pump against the high resistence of the pulomary veins) -- inability to have a symmetrical, aesthetically pleasing location for the umbilicus -- the heart itself would receive the least oxygenated blood, since the coronary arteries are located on the very end of this "improved" CV system Again, I will list advantages of the ductus arteriosus: � protects lungs against circulatory overload � allows the right ventricle to strengthen � hi pulmonary vascular resistance, low pulmonary blood flow <a href="http://mcb.berkeley.edu/courses/mcb135e/fetal.html" target="_blank">http://mcb.berkeley.edu/courses/mcb135e/fetal.html</a> John [ October 25, 2002: Message edited by: Vanderzyden ] [ October 25, 2002: Message edited by: Vanderzyden ]</p>

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10-24-2002, 08:50 PM	#141
lpetrich Contributor Join Date: Jul 2000 Location: Lebanon, OR, USA Posts: 16,829	Vanderzyden has FINALLY noticed me. Thanx, O Vandie. 1. What life form isn't "constrained" by its biology? For that matter, what being isn't constrained by its nature? Humans aren't constrained. They rule the animal kingdom and the planet. How is that? They have MINDS. You and I have been over this ground before. So there is some sort of mind-stuff that is lacking in the rest of the animal kingdom? O Vanderzyden, I suggest that you study chimpanzee behavior some time. If you think that chimps do not have minds, I'd be willing to learn your reasons. 2. OK, humans are more similar to chimps than fish. So? Despite our similarities, our physiology is still significantly different. And, again, you know that the sensibility of Darwinism is the subject of much debate. Significantly different in what way? Be specific. I'd like to know what you have in mind. 3. No, comparitive embryology provides no extant support for Darwinism. It, too, is just one more "icon" of that belief system. Again, homology is not de facto evidence of common descent. There are other explanations that are categorically rejected by the Darwinist. (This point also addresses lpetrich's "data"). The only sensible form of creationism that could account for such features is pseudo-evolutionary creationism -- creationism that closely mimics descent with modification, something like an old-earth version of Philip Gosse's "Omphalos" hypothesis. That is not an ABSOLUTE impossibility, but it is as pointless as Gosse's original hypothesis, that of a young earth created with an old-earth appearance. Vanderzyden, I challenge you to account for early-embryonic circulation, multiple aortas and aortic arches and all, without resorting to pseudo-evolutionary creationism. And I mean by that something like "The creator was too lazy to completely redesign the circulatory systems of land vertebrates so that they'd always be in land-animal configuration. So he/she/it made them develop like fish, then made them reorganize their blood vessels." or "The creator could not think of a good way to make jaws from scratch, so he/she/it induced the first gill bars in sequence to become jaws." or "The creator decided to make an early mammal's left systemic arch drop out and an early bird's right systemic arch drop out -- and then lazily copied those arrangements for all subsequent mammals and birds, without ever entertaining him/her/itself by creating some with the opposite systemic arch dropping out."

10-25-2002, 12:15 AM	#145
scigirl Veteran Member Join Date: Jul 2001 Location: Seattle Posts: 4,261	Ok one more link... since the topic of this thread is "fetal circulation," I thought we needed a good overview of the placenta (warning - there is a picture..." scigirl <a href="http://www.sccs.swarthmore.edu/users/98/amita/embryo.html" target="_blank">http://www.sccs.swarthmore.edu/users/98/amita/embryo.html</a>

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