Hello sc1898,
The quantitative measurement of synovial fluid viscosity is described
in a M.Eng thesis submitted in 2001 to the University of Florida by
Bryan Preston Conrad “The effects of glucosamine and chondroitin on
the viscosity of synovial fluid in patients with osteoarthritis”. The
complete thesis is available in pdf format at:
http://etd.fcla.edu/etd/uf/2001/anp4318/B.CONRAD-THESIS8-03.pdf
Details of how the viscosity is measured appear on pages 24-28 (nb
these are the page numbers of the original thesis, and are equivalent
to pages 35-39 of the pdf document).
Basically, a microrheometer developed in the laboratory of the author
was used to measure viscosity where less than 0.5 ml of synovial fluid
was present. If more than 0.5 ml was available, viscosity was also
measured using a Brookfield cone-plate viscometer.
“Microrheometer measurements were made with a 1.01 mm diameter
magnetic iron cylinder (Fisher Scientific) and a 1.61 mm inner
diameter glass sample tube also at 25 deg C.All cone-plate
measurements were made with a cp-52 cone (3 deg angle, 0.5 mL fluid)
at 25 deg C. Viscosity was measured at 6 different shear rates on the
cone-plate viscometer to evaluate non- newtonian behavior of the
synovial fluids. The most relevant difference between the two
rheometers is that the microrheometer applies a known force to a
cylinder (gravity) and measures the change in shear rate (falling
velocity), whereas the cone-plate viscometer applies a known shear
rate to the sample and measures the torque response through the
spindle. Therefore, for non-newtonian fluids, a correction must be
made to compare the apparent viscosity derived from the microrheometer
and that measured from cone-plate viscometer. To compensate for the
difference, the viscosity versus shear rate curve plotted from the
coneplate viscometer must be extrapolated to the shear rate of the
microrheometer and at that shear rate the two values can be compared.”
In order to validate and calibrate the microrheometer, results were
compared with those from the cone-plate viscometer for a range of
newtonian (oils) and non-newtonian (hyaluronic acids) fluids with
known properties.
A full description of the microrheometer and its use, together with a
diagram and associated equations, appears in the thesis. A diagram is
also available on a web page summarizing Bryan Conrad’s research:
http://www.aero.ufl.edu/~cellmech/projects/bryan/bryan.htm
The microrheometer was first described in: Tran-Son-Tay, R., Beaty,
B.B., Acker, D.N., Horchmuth, R.M. Magnetically Driven, Acoustically
tracked, translating-ball Rheometer for Small Opaque Samples. Reviews
of Scientific Instruments, 1988. 59: p. 1399-1404.
A description of the Brookfield cone-plate viscometer is available on
the web site of the manufacturer:
http://www.brookfieldengineering.com/products/laboratory/well.cfm ,
while at http://www.engin.brown.edu/courses/en81/Lab%20Stuff/lab1_2002final.doc
there is a description of its use in a student laboratory assignment
during a course in fluid mechanics.
Bryan Conrad is now also using a Q-Sense quartz crystal microbalance
to measure the viscoelastic properties of both diseased and healthy
fluids.
“By collecting both the dissipation and the resonance frequency of a
quartz crystal, Q-Sense has developed a technology that can be used to
study the formation of thin films such as proteins, polymers and cells
onto surfaces in liquid. This is QCM-D (Quartz Crystal Microbalance
with Dissipation monitoring)… A film that is "soft" (viscoelastic)
will not fully couple to the oscillation of the crystal which dampens
the crystal's oscillation. The dissipation (D) of the crystal's
oscillation is a measure of the film's softness (viscoelasticity)….
Q-Sense D300 is the first commercially available Multi-Frequency
Quartz Crystal Microbalance (QCM) capable of measuring changes in
structural, i.e. viscoelastic changes, in ultra thin layers in
real-time”
From the Q-Sense web site: http://www.q-sense.com/
It seems that for diagnostic purposes, a simple visual estimate of
whether viscosity is high or low is more frequently used:
“The viscosity of synovial fluid can be assessed at the time of
aspiration by noting the length of the "string" of synovial fluid that
forms when synovial fluid is dripped from the tip of the aspiration
needle onto a microscope slide, or when the needle is rapidly lifted
from a slide containing a drop of synovial fluid. Normal synovial
fluid forms a "string" of several inches. As the high molecular weight
proteoglycans contained in normal synovial fluid are degraded by
inflammatory cell enzymes, the fluid becomes less viscous and no
string forms.”
Synovial Fluid Analysis by Mark H Wener MD, Rheumatology and
Laboratory Medicine, University of Washington School of Medicine,
Seattle
http://www.rheumatology.org/publications/primarycare/number6/hrh0033698.html
For example, here is a table which, among other things, relates four
degrees of viscosity (from very high to runny) with the degree of
arthritic inflammation
http://www.eular.org/synovial/3_04.htm
A detailed discussion of synovial fluids, and its aspiration and
examination is available in a chapter by Alan J. Lipowitz in Textbook
of small animal orthopaedics (Charles D Newton and David M Nunamaker)
http://cal.nbc.upenn.edu/saortho/chapter_86/86mast.htm |
Clarification of Answer by
tehuti-ga
on
31 Dec 2002 11:25 PST
Hello sc1989,
The microrheometer, as described in the thesis, is not a commercial
piece of equipment, but was pieced together in the Cellular Mechanics
and Biorheology Laboratory of the University of Florida.
It uses a spherical steel ball or a small steel cylinder (c. 1mm
diameter) placed concentrically in a small glass tube with a volume of
about 20 ml (inner diameter of 1.6 mm and a height of 10 mm). A 20 ml
sample is loaded, by retrograde injection, into this tube and the tube
is centered inside a cylindrical, Plexiglas, water-jacket. An
ultrasonic transducer, with a piezoelectric crystal, is positioned at
the bottom of the Plexiglas chamber. An O-ring is used to obtain a
watertight seal with the base of the sample tube and with the
transducer. A plastic cap is screwed over the top of the water jacket
to protect the sample. The steel ball or cylinder is dropped into
the centre of the sample tube using a small electromagnet coupled with
a micromanipulator. The pulse-echo mode is used to locate and track
the falling cylinder. A single sound pulse is transmitted into the
fluid medium by pulsing an ultrasound transducer that also acts as a
receiver. Any returning echoes from the cylinder cause a voltage rise
across the transducer that is amplified by the ultrasonic
pulser/receiver unit (Panametrics 5052 PR).
Thus, the components required are: steel ball or cylinder; glass
sample tube; ultrasound transducer with piezoelectric crystal
(pulser/receiver); cylindrical Plexiglass water jacket; electromagnet;
micromanipulator; pulser/receiver. There is another schematic diagram
of the microrheometer at http://www.aero.ufl.edu/~cellmech/facility/
I went onto the Panametrics site, and found the the 5052PR
pulser/receiver is no longer listed, but nine other models of
pulser-receiver are available. Unfortunately, no price details are
supplied. http://www.panametrics.com/div_ndt/pages/products/instrument/index.shtml
I did find a secondhand Panametrics 5072PR 35 MHz Ultrasonic Pulser /
Receiver on offer at:
http://used-line.com/cgi-bin/a_view/view_item.cfm?itemID=4174716 , but
again with no price quoted.
I think that the best person to give you an estimate of the cost, and
of the complexity or otherwise of constructing this equipment would be
Bryan Conrad, or the originator of the equipment, Dr. Roger
Tran-Son-Tay. They would also be able to give you exact
specifications for the components and indicate suitable suppliers. If
you wish, I can attempt to make email contact with these people on
your behalf (I cannot telephone since I am based in the UK). However,
I sincerely think it would probably be more effective for you to do
so, since you will be able to explain your project to them and also
establish a useful contact with people working in the same field.
The contact details are:
Dr. Roger Tran-Son-Tay (Director) email: rtst@ufl.edu tel: (352)
392-6229
Bryan Conrad (graduate student) email: conrabp@ortho.ufl.edu
Cellular Mechanics and Biorheology Laboratory
University of Florida.
203 Aerospace Bldg. PO BOX 116250.
Gainesville, FL32611-6250
Tel: (352) 392-1753 Fax: (352) 392-7303
By the way, in your original question, you asked whether it was
possible to use a couette, rotational or oscillation viscometer to
measure the viscosity of synovial fluid. All three types have been
reported as being used for this purpose, as noted in Bryan Conrad’s
thesis:
Couette:
Davis, W.H., Jr., Lee, S.L., and Sokoloff, L., Boundary lubricating
ability of
synovial fluid in degenerative joint disease. Arthritis Rheum, 1978.
21(7): p. 754-
6. (human post-mortem)
Ogston, A. and Stanier, J., The physiological function of hyaluronic
acid in
synovial fluid: viscous, elastic and lubricant properties. J.
Physiol., 1953. 119: p.
244. (bovine)
Contraves Rotational:
Schurz, J. and Ribitsch, V., Rheology of synovial fluid. Biorheology,
1987. 24(4):
p. 385-99. (human post-mortem)
Oscillating Capillary:
Anadere, I., Chmiel, H., and Laschner, W., Viscoelasticity of "normal"
and
pathological synovial fluid. Biorheology, 1979. 16(3): p. 179-84.
(patients with meniscus defects or knee disease)
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