Jean, I have some responses to your questions/theories, that I hope will
clarify some misconceptions regarding Donna's research. I have discussed the
ultrasound responses with Donna prior to sending. I do understand it is
often difficult when only having spoken word and memory available and that
misinterpretation is more likely then, than when having the written work to
refer to. Unfortunately Donna will not be at ILCA in Sydney, but Peter
Hartmann, Leon Mitoulas, Jaquie Kent and myself will be there and will
happily answer anyone's questions. Apologies for length but I have
incorporated original question/statements for clarity.

> I would very much like to have access to anything and everything that may
> have thus far been published by her (and the group) on this subject. Does
> it consist solely thus far of proceedings and transcripts of talks to
> various groups???
Yes, nothing as yet has being published but will be submitted soon, which
means it is at least a year away before publication
Existing abstracts from conference proceedings are:

Ramsay, Kent & Hartmann.2002(?) Ultrasound Imaging of the Anatomy Human
Lactating Breast. Perinatal Society for Aust & NZ.

Ramsay, Kent, Owens & Hartmann. 2001. Ultrasound imaging of milk ejection in
the human lactating breast. Proceedings of the Society for Reproductive
Biology. Abstract No 30.

> I have held the opinion (by logic alone) for a long time that whatever
> milk is not removed does in fact at least begin to separate so that the
> fat globules, by virtue of their specific gravity (and perhaps the fact
> that "oil and water don't mix") rise within the ducts, against gravity,
> toward the ceiling. (like the cream in the milk bottles left on the
> doorstep when I was a kid.)
>
> Solely in my mind's eye, based on the physics described above, depending
> on the mother's position (upright, for between 2-16 hours with infrequent
> MER's, or lying down for 2-3 hours in any one same position with
> infrequent MER's, as while asleep) more fat globules would end up either
> at the upper parts and walls of all the ducts outside the lobules were
> she sitting or standing, or on the upper wall of most all ducts, were she
> sidelying. This would then effect the % of cream arriving forward in the
> breast at the next MER. This, therefore would explain some of the
> conflicting findings and opinions about foremilk and hindmilk.

Most (70%) of the variation in fat is due to breast fullness (which is in
turn related to time since last feed) . Currently accepted theory of
fore/hind differences is:

-fat has a tendency to stick to other fat molecules forming even larger
particles. The longer the time between feeds the more likely fat is to
ADSORB (ie be attracted to and stick to, as opposed to ABSORD) to each other
and the alveoli walls (and possibly ductal walls too)
-These large particles of fat  move slowly (relative to other milk
components)  away from the alveoli during commencement of a let down

-As flow picks up during a let down the fat particles are dislodged from
walls and begin to flow faster from the alveoli, also the contraction of the
myoepithelial cells around the now less full alveoli also  dislodges the fat
and pushes the clumps of fat out through the duct.

-also because of the simultaneous MER occurring in the breast not being fed
from, you will find that the foremilk from this breast will have a higher
fat conc'n because of the mixing caused by the MER occurring within a
"closed breast".

Donna has been able to visualize fat in the ducts (fat is quite obvious on
ultrasound) and during a let down there is no separation out of the fat in
milk in the ducts during MER.

> And I can also understand that the dilatation of the ducts is temporary
> during the height of the surge of the MER and that no large amounts are
> stored in the ducts such as are stored in the udders of dairy animals.
>I  have a wonderful line diagram from the veterinary literature of the
> 1950's by Dr. Linzell, I believe, illustrating how ducts shorten in
> length and dilate in circumference during the MER. It is my understanding
> from what I have heard at several talks by Dr. Hartmann that this is
> pretty much like one of the processes demonstrated by the current US
> research

The amount of milk present in the resting ducts will depend on the
individual variation in each mother's ductal anatomy.
 For example resting duct diameter ranges from 1-10mm, average 2-3 mm.
Where resting duct diameter is large and there is a large numbers of ducts
(comparatively) this woman can, say, express up to 35mls before ever having
a milk ejection, in contrast to the woman with 1 mm ducts whom you can get
out (express) next to nothing prior to MER. Donna has observed that large
diameter ducts only dilate up a small amount comparatively during MER.
The diameter of the ducts is consistent with no dilatation of the ducts
where previously "the lactiferous sinuses" where thought to be.  Branching
occurrs within a radius of 16 mm from the centre of the nipple, Some
widening was observed where ducts branch. Donna's findings in regard to this
is that the ducts are not used to "store milk" but to transport it.

> It stands to reason (solely by my logic, for the sake of my own questions
> about "why" things happen), that once the contraction of the
> myoepithelial cells relaxed and the shape of the ducts resumed their
> original longer length and narrower circumference, that the positive
> pressure of the duct walls would cause some redistribution of the milk in
> the direction of the upper collecting ducts. I personally cannot believe
> though, that they are totally "empty" of milk however. I think this is
> part of the mechanism that makes massage and breast compression effective
> as feeding/pumping tools. And also part of the mechanism contributing to
> plugged ducts if milk is not kept moving.
> But if <She has documented that milk moves down from the alveoli during
> milk-ejection, is
> available for 2 or 3 minutes or so, then what hasn't been removed moves
> back up to the alveoli again.> is actually precisely what she said, it
> seems to me that that's inaccurate and mileading terminology.
>
> I could accept "toward the alveoli". But to say it "goes back up to the
> alveoli" should not be presumed to create such an absolutely precise
> representation of exactly what's happening. We are not being told about
> electron microscopic pictures of ductal lumens here. We are being told
> about ultrasound shadows and her interpretation thereof.
I can see ultrasonographers and obstetric sonographers worldwide will be
turning purple over this comment :-) Interpretation of ultrasound images is
a science which is widely used (and validated) in medical science and
diagnoses.

Donna has never suggested that the ducts become empty of milk after a MER,
just that they resume their pre MER diameter, which necessitates that the
increased volume in the dilated ducts during a MER must "go somewhere" if
the breast is not being fed from or expressed (or is not dripping). (her
current research is on the breast not being fed from (while feeding takes
place) and on breasts being expressed). She has observed milk to flow
backwards down the duct (towards the alveoli as opposed to forwards towards
the nipple) following completion of a MER. This may perhaps be in part due
to the action of the muscular sphincter of the nipple, closing off following
the end of MER (theory only). The observed diameter does not always return
totally to baseline (pre MER diameter) immediately following end of MER,
especially if followed closely by another MER. I think Donna has observed a
maximum of 7- 9 MER in one feed.
.

> The alveoli are arranged in small groups draining into a common vestibule
> all of which form a lobule. The lobule is connected by a ductule to the
> first collecting duct to which an MER will eventually transfer the milk.
> The ductule is made differently, I believe, than a duct, ( I don't have
> my references with me on vacation). Milk collects in the vestibule after
> it has been secreted through the alveolar membrane but before it has been
> forced through the ductule by an MER.   Off the top of my head, it seems
> to me that it is impossible for the milk to re-enter through the ductule
> back into the common vestibule of the lobule into which the alveoli open.

Donna has not been able to visualize alveoli and has not stated that milk
travels back into the alveoli, only that it travels back into the breast
"towards the alveoli".
Incidentally, I have, in the last two weeks, had the pleasure of viewing the
original 1840 drawings and manuscripts by Cooper (they are magnificent
pieces of meticulous work). It is worth commenting that the sections of
breast drawn, where "draped" over stones, probably in a "neat" way to
facilitate understanding and drawing of the structures. It is probable that
he may have teased out the lobes and the ducts so that they could be "seen",
which has resulted in that characteristic bicycle spoke traditional view we
have held for so long (which is not anywhere near so neat in reality, eg:
very little glandular tissue in the medial aspect of the breast.) Also the
ductography was done with wax (ie the ducts were injected from the nipple
pores with molten wax to delineate them) probably resulting in the artifact
of dilation that we subsequently called lactiferous sinuses, and because of
their structure thought they were storage spaces.

Warm regards
Cathy Fetherston CM MSc IBCLC
Biochemistry and Molecular Biology
School of Biomedical and Chemical Sciences
The University of Western Australia

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