805
Sequential Multi-Analyser with Computer Technicon) program was used for the measurement of urinary creatinine, serum-electrolytes, and liver and kidney function friend.5 A standard
tests.
&bgr;2-MICROGLOBULIN IN UPPER AND LOWER URINARY-TRACT INFECTIONS
URINARY
G. SCHARDIJN A.
J.
L. W. STATIUS G. SWAAK
VAN
EPS
Department of Internal Medicine, Slotervaart Hospital,
RESULTS AND DISCUSSION
Amsterdam, The Netherlands
patients administration of A.P.D. was followed reduction of serum-calcium to around 2-0 mmol/1, irrespective of the initial serum-calcium concentration (see figure). The lowest level of serum-calcium was generally observed within a week, although minimum values were not reached in patients H and I until after 21 and 15 days (not shown in figure), respectively. The fall in serum-calcium was accompanied by a decrease towards normal or very low excretion-rates of calcium into the urine. Urinary excretion of OHp also decreased and became normal in most patients. Our experience in patients with Paget’s disease! indicates that hypocalcaemia during administration of A.P.D. is accompanied by increased absorption of calcium from the gut. The lowering in serum-calcium was therefore due to reduction in bone resorption rather than to any change in calcium transport in kidneys or gut.’ Massive osteolysis due to malignancy, indicated by hypercalciuria and a raised excretion-rate of OHP, was apparently inhibited by A.P. D. It should be noted that although serum-calcium dropped to hypocalcaemic values, it was never below 1.6mmol/1 and it was generally around 2.0 mmol/1. In all
bv
a
These levels
were not
accompanied by hypocalcxmic
symptoms. In most respects the drug was well tolerated. Some patients had slight gastric discomfort, though never severe enough to make them wish to discontinue treatment. A transient rise of body temperature of 1-2’C, never lasting for more than 72 h, occurred in some patients when urinary OHP was falling rapidly. It was not associated with an increased production of uric acid or with leuco-
cytosis. These preliminary results indicate that tumourinduced osteolysis may be inhibited by A.P.D. and that the agent may be useful in the treatment of hypercalcxmia due to tumours. Further studies are needed to determine whether this effect can be maintained over longer periods and whether the drug may be used to prevent the further development of destructive bone lesions in malignant disease. This work was partly supported by the Foundation for Medical Research (FUNGO), which is subsidised by the Netherlands Organisafor the Advancement of Pure Research donated by Henkel KGaA, Diisseldorf tion
(Z.W.O.).
A.P.D. was
Requests for reprints should be addressed to 0. L. M. B., Clinical Investigation Unit, Department of Clinical Endocrinology and Metabolism, University Hospital, Leiden, The Netherlands.
REFERENCES
Frijlink,
W
B., Bijvoet, O. L. M., Velde, J.
te,
Heymen, G. Lancet, 1979,
i, 799.
Galasko, C. S B. Nature, 1976, 263, 507. Mundy, G. R., Raisz, L. G., Cooper, R. A., Schechter, G. P., Salmon, S. E. New Engl J Med. 1974, 291, 1041. 4. Alexanian, R., Haut, A., Khan, A. U., Lane, M., Mc. Kelvey, E. M., Migilore, P. J, Stuckey, W. J., Wilson, H. E. J. Am. med. Ass. 1969, 208, 1680
5. Prockop, D. J., Udenfriend, S.
Anal. Biochem.
1960, 1, 228.
J. P. PERSIJN
J. C. G. M. KAGER
Department of Clinical Chemistry, Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands excretion in 24 h urine collections and &bgr;2-microglobulin clearance were significantly increased in patients with upperurinary-tract infections, but &bgr;2-microglobulin clearance and excretion were normal in patients with cystitis. &bgr;2-microglobulin estimation may be used to distinguish between upper and lower urinary-tract infections, except when pre-existing tubular damage is present. Voided urine must have a pH above 6·0, since &bgr;2-microglobulin is rapidly degraded in the bladder at low pH.
Summary
&bgr;2-microglobulin
INTRODUCTION a small protein with a molecular of 11 800 daltons.1 It is synthesised by most nucweight leated cells, is present on their surfaces, and is closely associated with immunoglobulins and cell-surface histocompatibility antigens. It is secreted in serum and other body-fluids. Individual daily production is constant and serum concentration is usually stable, with a mean value of 1.8mg/1. Like creatinine, it passes easily through the glomerular membrane but unlike creatinine it is almost completely reabsorbed in -the proximal tubules of the kidney where it is metabolised.2-4 Therefore, there is a very close, inversely proportional relation between plasma-P2-microglobulin and glomerular filtration-rate. In normal people, glomerular filtration of p2-microglobulin is approximately 340 mg/day. Maximum daily excretion in urine, however, amounts to only 370 g—i.e., 0.1% of the amount filtered. Increased p2-microglobulin excretion has been reported in association with renal diseases characterised by tubular damage.-e.g., in Balkan nephropathy5 or in patients with chronic cadmium poisoning. We measured urinary excretion and renal clearance of P2-microglobulin in patients with upper and lower urinary-tract infections. Since there is tubular involvement in upperurinary-tract infection, we hoped to be able to distinguish between upper and lower urinary-tract infections on the basis of urinary excretion of
P2-MICROGLOBULIN is
P2-microglobulin. METHODS
22-microglobulin was measured by solid-phase radioimmunoassay (’Phadebas’, Pharmacia). Each sample was analysed twice. As 2-microglobulin is rapidly degraded at pH below 6, 1,2 we studied the stability of 2-microglobulin under conditions of pH and temperature which reproduced the normal situation of urine in the human bladder before voiding. Samples of a 24 h urine collection were titrated to achieve different pH levels, as indicated in fig. 1, and these were then incubated at 37°C for 2 h. After incubation the pH was immediately adjusted to 7-4. These samples were then incubated with labelled 2-Microglobulin and 02-microglobulin antiserum, and
806
&bgr;2-microglobulin was determined by radioimmunoassay.
COMPARISON OF RESULTS IN PATIENTS WITH UPPER U.T.I. OR
the subjects were given4 g of To ensure a urinary pH>6, sodium bicarbonate on the evening preceding the experiment and another 4 g in four divided doses next day, during which urine was collected for 24 h. With these measures most urine collections had a pH of more than 6. Only urine specimens with a pH>6 were assayed. Ten patients (aged 50-84) with pyelonephritis were studied. Diagnostic criteria were as follows: (1) Urosepsis with urine and blood cultures positive for the same microorganism (seven cases). None was complicated by shock. The causative organism was Escherichia coli in six patients and Pseudomonas aeruginosa in one patient; (2) A positive scintiphotograph with gallium-67 citrate7
LOWER U.T.I. AND CONTROLS
(four cases); (3) An abnormal intravenous pyelogram which accorded with a diagnosis of pyelonephritis (nine cases). Patients who satisfied at least two of these criteria were investigated. The causative organisms in the three patients without a positive blood-culture were E. coli, Ps. aeruginosa, and Proteus mirabilis.
*A vs. Band C, P
Sequential Multi-Analyser with Computer Technicon) program was used for the measurement of urinary creatinine, serum-electrolytes, and liver and kidney function friend.5 A standard
tests.
&bgr;2-MICROGLOBULIN IN UPPER AND LOWER URINARY-TRACT INFECTIONS
URINARY
G. SCHARDIJN A.
J.
L. W. STATIUS G. SWAAK
VAN
EPS
Department of Internal Medicine, Slotervaart Hospital,
RESULTS AND DISCUSSION
Amsterdam, The Netherlands
patients administration of A.P.D. was followed reduction of serum-calcium to around 2-0 mmol/1, irrespective of the initial serum-calcium concentration (see figure). The lowest level of serum-calcium was generally observed within a week, although minimum values were not reached in patients H and I until after 21 and 15 days (not shown in figure), respectively. The fall in serum-calcium was accompanied by a decrease towards normal or very low excretion-rates of calcium into the urine. Urinary excretion of OHp also decreased and became normal in most patients. Our experience in patients with Paget’s disease! indicates that hypocalcaemia during administration of A.P.D. is accompanied by increased absorption of calcium from the gut. The lowering in serum-calcium was therefore due to reduction in bone resorption rather than to any change in calcium transport in kidneys or gut.’ Massive osteolysis due to malignancy, indicated by hypercalciuria and a raised excretion-rate of OHP, was apparently inhibited by A.P. D. It should be noted that although serum-calcium dropped to hypocalcaemic values, it was never below 1.6mmol/1 and it was generally around 2.0 mmol/1. In all
bv
a
These levels
were not
accompanied by hypocalcxmic
symptoms. In most respects the drug was well tolerated. Some patients had slight gastric discomfort, though never severe enough to make them wish to discontinue treatment. A transient rise of body temperature of 1-2’C, never lasting for more than 72 h, occurred in some patients when urinary OHP was falling rapidly. It was not associated with an increased production of uric acid or with leuco-
cytosis. These preliminary results indicate that tumourinduced osteolysis may be inhibited by A.P.D. and that the agent may be useful in the treatment of hypercalcxmia due to tumours. Further studies are needed to determine whether this effect can be maintained over longer periods and whether the drug may be used to prevent the further development of destructive bone lesions in malignant disease. This work was partly supported by the Foundation for Medical Research (FUNGO), which is subsidised by the Netherlands Organisafor the Advancement of Pure Research donated by Henkel KGaA, Diisseldorf tion
(Z.W.O.).
A.P.D. was
Requests for reprints should be addressed to 0. L. M. B., Clinical Investigation Unit, Department of Clinical Endocrinology and Metabolism, University Hospital, Leiden, The Netherlands.
REFERENCES
Frijlink,
W
B., Bijvoet, O. L. M., Velde, J.
te,
Heymen, G. Lancet, 1979,
i, 799.
Galasko, C. S B. Nature, 1976, 263, 507. Mundy, G. R., Raisz, L. G., Cooper, R. A., Schechter, G. P., Salmon, S. E. New Engl J Med. 1974, 291, 1041. 4. Alexanian, R., Haut, A., Khan, A. U., Lane, M., Mc. Kelvey, E. M., Migilore, P. J, Stuckey, W. J., Wilson, H. E. J. Am. med. Ass. 1969, 208, 1680
5. Prockop, D. J., Udenfriend, S.
Anal. Biochem.
1960, 1, 228.
J. P. PERSIJN
J. C. G. M. KAGER
Department of Clinical Chemistry, Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands excretion in 24 h urine collections and &bgr;2-microglobulin clearance were significantly increased in patients with upperurinary-tract infections, but &bgr;2-microglobulin clearance and excretion were normal in patients with cystitis. &bgr;2-microglobulin estimation may be used to distinguish between upper and lower urinary-tract infections, except when pre-existing tubular damage is present. Voided urine must have a pH above 6·0, since &bgr;2-microglobulin is rapidly degraded in the bladder at low pH.
Summary
&bgr;2-microglobulin
INTRODUCTION a small protein with a molecular of 11 800 daltons.1 It is synthesised by most nucweight leated cells, is present on their surfaces, and is closely associated with immunoglobulins and cell-surface histocompatibility antigens. It is secreted in serum and other body-fluids. Individual daily production is constant and serum concentration is usually stable, with a mean value of 1.8mg/1. Like creatinine, it passes easily through the glomerular membrane but unlike creatinine it is almost completely reabsorbed in -the proximal tubules of the kidney where it is metabolised.2-4 Therefore, there is a very close, inversely proportional relation between plasma-P2-microglobulin and glomerular filtration-rate. In normal people, glomerular filtration of p2-microglobulin is approximately 340 mg/day. Maximum daily excretion in urine, however, amounts to only 370 g—i.e., 0.1% of the amount filtered. Increased p2-microglobulin excretion has been reported in association with renal diseases characterised by tubular damage.-e.g., in Balkan nephropathy5 or in patients with chronic cadmium poisoning. We measured urinary excretion and renal clearance of P2-microglobulin in patients with upper and lower urinary-tract infections. Since there is tubular involvement in upperurinary-tract infection, we hoped to be able to distinguish between upper and lower urinary-tract infections on the basis of urinary excretion of
P2-MICROGLOBULIN is
P2-microglobulin. METHODS
22-microglobulin was measured by solid-phase radioimmunoassay (’Phadebas’, Pharmacia). Each sample was analysed twice. As 2-microglobulin is rapidly degraded at pH below 6, 1,2 we studied the stability of 2-microglobulin under conditions of pH and temperature which reproduced the normal situation of urine in the human bladder before voiding. Samples of a 24 h urine collection were titrated to achieve different pH levels, as indicated in fig. 1, and these were then incubated at 37°C for 2 h. After incubation the pH was immediately adjusted to 7-4. These samples were then incubated with labelled 2-Microglobulin and 02-microglobulin antiserum, and
806
&bgr;2-microglobulin was determined by radioimmunoassay.
COMPARISON OF RESULTS IN PATIENTS WITH UPPER U.T.I. OR
the subjects were given4 g of To ensure a urinary pH>6, sodium bicarbonate on the evening preceding the experiment and another 4 g in four divided doses next day, during which urine was collected for 24 h. With these measures most urine collections had a pH of more than 6. Only urine specimens with a pH>6 were assayed. Ten patients (aged 50-84) with pyelonephritis were studied. Diagnostic criteria were as follows: (1) Urosepsis with urine and blood cultures positive for the same microorganism (seven cases). None was complicated by shock. The causative organism was Escherichia coli in six patients and Pseudomonas aeruginosa in one patient; (2) A positive scintiphotograph with gallium-67 citrate7
LOWER U.T.I. AND CONTROLS
(four cases); (3) An abnormal intravenous pyelogram which accorded with a diagnosis of pyelonephritis (nine cases). Patients who satisfied at least two of these criteria were investigated. The causative organisms in the three patients without a positive blood-culture were E. coli, Ps. aeruginosa, and Proteus mirabilis.
*A vs. Band C, P
