Læknablaðið : fylgirit - 01.05.1978, Side 23

Pernille Möller Graabæk
& Susanne Möller Pedersen
Department of Rheumatology, University ofÁrhus,
Árhus Kommunehospital, DK-8000 Árhus C.
ABSTRACT
A preliminary investigation of serum gold
concentrations in 26 patients with definite rheuma-
toid arthritis is presented. The patients are in
long term gold therapy with the dose adjusted
individually as the smallest dose giving a satisfac-
tory clinical effect. Gold was determined by
flameless atomic absorption spectroscopy, using
a reliable method to be published elsewhere. 18
patients treated with Sanocrysin (Aurotiosulfate)
were found to have gold concentrations in the
range 27 - 270 ug/100 ml serum. 8 patients
treated with Myocrisin (Aurotiomalate) had gold
concentrations in the range 34 - 60 ug/100 ml.
serum. These concentrations are the values
immediately before the next gold injection. For
a constant dose/interval the gold concentration
for any patient was constant during the investiga-
tion.
Since the late nineteen-sixties atomic absorp-
tion spectro-scopy (AAS) has been used to deter-
mine gold in biological fluids.
In the main the atomic absorption spectrophoto-
meter consists of an.atomizer, a monochromator,
and a photodetector. The light source is a gold
hollow-cathode lamp emitting a spectrum of lines
with different frequencies characteristic of gold.
The atomizer is a reservoir into which the
sample is being applied. Tlie monochromator
is a filter adjusted to allow only the most
sensitive line - at which the gold absorb - to
reach the photodetector. The line is called the
"resonance" line. The photodetector measures
the intensity of the light, "resonance" line,
passing through the monochromator. In case of
gold in the sample the gold will absorb the
"resonance" line and the photodetector will
register this as a reduction in the light intensity.
It has been stressed that by atomic absorption
methods no interferences occur which means that
all the gold and only the gold in the sample will
absorb at the chosen "resonance" line. It has
appeared, however, that interference is the main
problem of this method - especially in case of
determination of gold in the urine.
Interference can be divided into chemical,
ionization, and matrix interferences. In case of
SERUM GOLD LEVELS IN
PATIENTS RECEIVING LONG
TERM CHRYSOTHERAPY
determination of gold in biological fluids matrix
interference - i.e. the influence of the solution
on the absorption signal - has presented the
biggest problem.
In our department we have elaborated a methodx)
for determination of gold in serum and urine
which is free from interference problems. In
principle the method consists in wet ashing,
extraction into methyl-iso-butyl-keton, and
following determination by flameless atomic
absorption spectroscopy. The method has a
sensitivity of 1 ug gold/100 ml which is on par
with that indicated for neutron activation analysis.
We have used the method for a preliminary
investigation of serum gold concentrations in 26
patients with definite rheumatoid arthritis (RA)
in long-term chrysotherapy. The treatment was
given as an individual treatment with the smallest
doses giving satisfactory clinical effect. The
patients' clinical conditions were satisfactory.
Of the 26 patients with RA 18 were treated with
sanocrysin and 8 with myocrisin. The two groups
were comparable as regards total dose, duration
of treatment, as well as dose/inteirval at the time
of analysis. (cf. table I).
In the myocrisin treated group the serum gold
concentrations varied from 34 to 60 ug/100 ml
and in the sanocrysin treated from 27 to 270
ug/100 ml. However, at constant dose/interval
the serum gold concentration in each individual
patient was constant. At the time of analysis no
patients showed signs of gold taxcity. Going
through the case sheets it appeared that 8 of the
18 patients treated with sanocrysin and 7 of the
8 patients treated with myocrisin had had toxic
reactions. As for all the patients the toxic
reactions had been mild and caused a temporary
pause in the treatment only. The total dose at
the time of toxicity was 1500 - 3000 mg.
Is it relevant to determine serum gold in
patients in long-term gold therapy? Yes, it is.
If the treatment is to be dosed according to a
fixed level as say about 300 ug gold/100 ml
serum - as Lorber et al*s investigation might
indicate (Ann. rheum. Dis. (1973), 32, 133) -
it is essential to be able to determine the serum
x) Susanne Möller Pedersen & Pernille Möller
Graabæk. Scand. J. clin. Lab. Invest. 1977.
21