*This machine-generated transcript may have errors. If remediation or a manually-generated transcript is needed, please contact NLM Support at https://support.nlm.nih.gov.*
this is a continuation and an extension of the paper
that was given at,
um,
the U C meeting in Amherst last
October.
And,
um,
if you need uh certain points
solicited,
let me know because I'll,
I'll explain them,
but I'm gonna sort of skip over things because I think time is short for a lot of
people here.
And it is for me,
I know,
um,
very few investigators have been willing to address the
problem of microwave cataract genesis from a
biochemical alteration standpoint.
And this lack of appeal seems ne
neglectful,
especially after it has been reported that a drop in
ascorbic acid levels in the lens of rabbits was
the first identifiable reaction to microwave
radiation and that this occurred before any
visible signs of damage were present.
Let us briefly review the literature dealing with
investigations of uh scic acid in
relation to microwave irradiation or the
eye Marro and Kenna Sheer in
1960 reported that reductions in ascorbic
acid of approximately 20% occurred in the lens of
the rabbit sometime between 16,
6 and 18 hours close to radiation.
They did not continue their study beyond this 18 hour
period.
Nor did they investigate any ties between the six and
18 hours.
They reported no decrease in the sic acid 18
hours post to radiation in the aqueous humor
and therefore ruled out the possibility that the
reduction in the lens was due to a decrease in this
fluid.
Ken demonstrated decreases in ascorbic
acid in a radiated rabid lens.
It's cultured in vitro.
However,
she states that the controls also lost
ascorbic acid but at a slower rate than the irradiated
lens.
Her results are ambiguous with large differences
being exhibited for the same culture periods,
white and reported that cultured rabbit
lenses lost asorbic acid when exposed to microwave
radiation and that this loss was due to thermal
increases with gradually increasing power
densities since portions of the lenses
during a radiation were exposed to the air.
one may question whether the decreases might have been
due to a surface evaporation and some cell
death occurred or the lenses lens capsule became a
leaky membrane.
Other investigators using labeled culture media
have found no differences in the uptake of ascorbic acid
between an exposed and control lens for periods up
to 19 hours post to radiation.
We recently reported results of a study of ascorbic
acid values in the vitreous lens and INAs of
rabbits.
Uh rabbit eyes exposed to single and multiple
repetitive uh multiple microwave
radiations lens.
Ascorbic acid levels appeared normal with the exception of
about a 20% in decrease at one week
post a radiation for an acute
exposure.
This drop was primarily coincident with the
appearance of lens opacities.
Do I control the slides?
Do I just?
All right.
OK.
Is that all right?
Very good.
This is a slide showing the
effect of a acid in the lens
at various times.
Post to radi radiation sacrifices from five
minutes to four weeks.
It will be noticed that Kitta had found
that at one at 18 hours
approximately right in this point here
that they had gotten a 20% drop.
The drop appears in hours to be at
one week post of radiation.
Oh,
I'm sorry,
at one week,
post radiation and then a
two weeks and at four weeks appears to be
within a normal range.
Again,
the dotted lines here are the multiple exposures
in the,
the,
the solid line is the single exposure.
This is uh that shows the results of
the AAA,
some of that looks in focus and some
everything in include uh seems to be within a
co control range.
And so therefore,
uh no effect seems to microwaves have no effect on the
Vitria of cervic acid levels.
In slide three.
Here we have data accumulated on the
uh the uh acres humor
and these levels indicate that the escort was
decreased in this fluid in an acutely
exposed eye.
And these levels do continue to decrease from
five minutes after the insult until a low was reached at one week.
Post radiation,
that's from this period to this period.
Recovery to normal values occurred by two weeks,
post of radiation and were still within control limits four
weeks after a radiation.
These results on the lens are not in agreement with those
reported by K Male and Kia.
A comparative analysis of the data at
18 hours poster radiation on the lens of score bait
collected by Mooli.
And that obtained by us showed that there is a significant difference
at the 99% confidence level between the right
irradiated I and the left control I for a
score bait levels in their study.
But this difference is not apparent for this post radio a
radiation period.
In our study,
the irradiation facilities,
equipment,
exposure conditions and analysis
mythology used in their study
is the same as that used in this recently reported
investigation.
However,
in their study,
the facility for radiation and the Nucleation of the
eye was located in a suburb while a
laboratory for scic acid analysis was a downtown
location.
As a possible reason for the discrepancies.
It was felt that the timing left between sacrifice of
the animal and removal of the eye.
Subsequent transportation of it to a cross town
laboratory and analysis of the specimen could be
of long duration compared to the entire operation of
sacrifice to section sample preparation
analysis steps being performed in sequence.
And at the same laboratory for our
study elapsed time from decease of the
animal to completion of analysis of all I
parts was 58 plus 58 plus
or minus eight minutes for all
76 animals in the study.
One can assume that analysis time for both studies
was the same but that transportation would delay
the S ay studies for for the original study.
More to test the delay hypothesis.
Alo watts of a known standard ascorbic acid solution were
taken at hour intervals over a period of five
hours and tied in the same manner as an actual sample.
The rate of decrease of dye used was 50
units per hour or the equivalent of point oh 19
mg of ascorbic acid per hour.
Over the first three hours and 20 units of dye
per hour or oh oh point oh oh seven mg of
ascorbic acid after three hours.
This means that after one hour,
approximately 20% of the ascorbic acid for titration
in this method has become unavailable.
A statistical analysis of the 76 duplicate
acids of lenticular mere material from
irradiated and controlled eyes showed no significant
difference with an average time between replicate analysis of
2 to 3 minutes.
When the second essay of lungs material is
delayed by one hour for both
control and irradiated eyes.
There is still no significant difference in
the uh significant difference due to the
delay.
This shows you the original analysis
done at time zero,
which I must say is
about 58 minutes.
The lens was the last part of the eye that we um
uh analyzed 60 minutes.
After that,
this is really no significant difference with
seven degrees of freedom.
And uh at that level,
one must therefore assume that the elapsed
time due to transportation of samples was not a
causative factor in obtaining differing results.
Gluta thion.
Another reducing substance is found in high concentration in the
lens of the eye.
This substance shows early decreased levels in ionizing
radiation produced cataracts.
It also reacts with the dye used in the titration
method for ascorbic acid.
However,
its rate of reaction is much slower than for ascorbic
acid to test whether it was acting as an
interference in our titration.
We add an amount of it normally present in the lens to a
standard known solution of a sate differences
in tita were not observed in solutions containing it from those
with no gluth present
in the course of our assay of a score in the in
the eyes part in the eye parts,
we weigh the lens immediately after a Nucleation and
just prior to homogenization in a protein
precipitant solution.
This offered us the opportunity to observe the relationship
between the weight ratio of the irradiated and
unirradiated lens to the severity of the damage
produced by the radiation observed,
observed just prior to sacrifice of
the animal and removal of the eye for analysis.
It also enabled us to determine
weight ratios at times after exposure.
But before any vis visible damage would be apparent by
slit lamp examination such as at five minutes
and a half hour and 12 hours and 18 hours post to
radiation.
Those eyes had no react observable
reaction to them.
This comparison was performed for those animals
exposed to both a single acute dose and a repetitive sub
subthreshold dose.
Minimal,
moderate and maximum response are categorized by Doctor
Copter.
In his previous studies,
minimal responses included small vesicles or Granules
along and near the post suture.
Cortical banding,
moderate responses responses showed
um
these uh small circumscribed opacities
occurring at the ends of the post suture.
This happens to be,
it looks like a vesicle right up in here.
The maximum type of response
was and the whole involvement of the whole posterior
castle.
A comparison of the weight ratio of the controls to mean
ratios of the various degrees of un observable
and observable damage shows that at 95%
confidence level,
there is no significant difference in the ratios for
all categories for both single and multiple
exposures.
A T value of 1.76
with 18 degrees of freedom was obtained when the greatest
differences are compared that between the
single maximal response and the controls.
And I'm talking about this,
which is the most obvious as compared to
this.
And there is no significant difference between those
and there is no significant difference in any of these.
So the weight of the lens or the severity of the damage has
nothing to do with the weight of the lens.
Morale and Kitta had raised the question in their
study as to whether an increase in temperature was the
cause of the observed drop in ascorbic acid in the
lens.
The scor acid is quite unstable and is
destroyed by heat in an alkaline solution.
The P H of the aqueous humor is about
7.57 to
7.6.
They checked the lens asorbic at a half hour and six
hours after a radiation and found no drop in ascorbic
acid and therefore ruled out heat
as a cause of the reduction.
They also tested the levels of score bait in the A in
the aqueous at 18 hours close to radiation
and found no change had occurred,
ruling out the possibility that a score bait was
unavailable to the lens and therefore resulted in the
lenticular decreases in
our experiments.
The acre had risen an average of
10.1 degrees C at the end of an acute
exposure.
As stated pre previously,
we found reduced levels of sate at five minutes
post to radiation and these levels continued to
decrease up until one week to
check whether the heat alone was directly responsible for the
drop observed in this fluid.
The eyes of rabbits were heated without the use of
microwaves and acid levels determined
the procedure was as follows.
An aqua of aqueous was removed from the left control
eye of an a,
an aet size rabbit and analyzed for aic
acid.
The ears of the rabbit were immersed in a hot water
bath at 50 degrees for 40 minutes.
Thereby heating the aqueous of the eye via the
circuitry system of the animal.
At the end of the heating period,
an aqua of aqueous fluid was removed from the right eye and
analyzed for a acid as an
additional test,
the action of the heat on the a as
as an additional test of the a the action of the heat
on the aqueous aquas of this fluid were
removed from both eyes of an anesthetized animal.
One aqua was heated to 55 degrees and both
aquas were analyzed for moving.
There is essentially uh
these are the in vivo heating.
And by that,
I mean that the ears were heated
from the left eye,
the aqua was removed prior to heating
from the right eye.
It was removed after heating and analyzed.
And there is essentially no difference
in here except the possibility of a slight increase
actually with the heated eye.
This was in vitro heating and this is when the
both the,
both the ques was removed from both eyes
and analyzed.
And there's essentially no difference there at all.
These are the controls.
It just as comparison here on the uh ratios on the control.
These results tend to negate the theory that heat
causes reduced levels of ate in the acres
with resultant lens decreases.
However,
the results do strengthen and lend support to the theory that
counteracter genesis is a secondary
reaction and that a primary and initiating action
for microwave damage is not a direct effect on the
lens of the eye or the fluids that bathe
it,
but a absorption of energy at some other sensitive
site which later is reflected as a damaged
lens.
This theory might possibly be tested
if it were possible that uh
the lens itself could be
directly uh
irradiated without peripheral tissue
being irradiated.
Future studies in this,
we hope to perhaps investigate the
role of the ciliary body or ciliary
epithelium in reducing its COVID appearing in the
aqueous.
And that uh this is perhaps the best way to do
this is with radioactive tracer techniques.
Uh Another investigative area is the role that
ascorbic acid plays in cataract genesis.
And this might be demonstrated by using
uh by studies using the guinea pig,
which does not synthesize the ascorbic acid except through
dietary means.
And I don't know,
but I just sort of thought of this at the end.
Uh I'm I'm not sure whether anybody has ever produced
cataracts in,
in rat lenses,
but uh it's an interesting observation
that there is absolutely no ascorbic acid
in the aqueous of a rat lens and the three
mg per percent in uh in the
aqueous.
Um I would appreciate
if Doctor Ravis,
if he's here,
his studies have closely coincided with what
we've been doing and I think that he came to somewhat some,
the same conclusion that possibly the sill
body or Elli is the
site that should be looked at.
I appreciate if he'd like to comment on it.
Is he here?
I guess so.