Beta 2-microglobulin Concentrations Research Articles

Detection of soluble interleukin-2 receptor and interleukin-10 in the serum of patients with aggressive non-Hodgkin's lymphoma. Identification of a subset at high risk of treatment failure.

This study explores the ability of the combined detection of soluble IL-2 receptor (sIL-2r) and interleukin-10 (IL-10) to predict treatment failure in patients with aggressive non-Hodgkin's lymphoma (NHL) and to evaluate the modifications in cytokine measurements induced by the therapeutic administration of recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF). Serum levels of sIL-2r and IL-10 were measured serially in 93 patients with newly diagnosed aggressive NHL treated with four courses of a multiagent chemotherapy regimen. GM-CSF was administered subcutaneously in 39 of these patients from day +5 to day +18 after each chemotherapy course. Pretreatment levels of sIL-2r were greatly elevated in patients with NHL compared with control subjects (P < 0.001), significantly correlating with the Ann Arbor stage (P < 0.001) and beta 2-microglobulin (beta 2-m) concentrations (r = 0.552, P = 0.004). IL-10 was detected in 37 patients at diagnosis, with no correlation with clinicohematologic parameters, and was not detected in the control sample (P < 0.001). Cytokine and receptor levels progressively declined to normal ranges in responding patients, whereas they remained elevated in nonresponders. During administration of GM-CSF, the authors observed an increase of sIL-2r, whereas lower elevations were recorded for IL-10. However, on completion of the induction treatment, cytokine/receptor levels were comparable in patients with the same type of response, whether or not they had received GM-CSF. In the five patients who were investigated at relapse, the levels of sIL-2r, beta 2-m, and lactic dehydrogenase were found to be elevated. IL-10 concentrations were high in three of these patients: two already had detectable levels at presentation, whereas one tested positive only on recurrence. No single parameter was associated with response to therapy, but the combination of elevated IL-10 and sIL-2r concentrations greater than 3000 U/ml resulted in a subset of eight patients who failed induction chemotherapy (P < 0.001). In addition, six of eight patients with high IL-10 and beta 2-m concentrations greater than 3.3 mg/l had an unfavorable outcome (P = 0.003). A multivariate regression model was used to identify sIL-2r (P = 0.004) and beta 2-m (P = 0.043) as the covariates that amplified the prognostic ability of IL-10. sIL-2r and IL-10 measurements provide valuable information for better management of patients with NHL as markers to monitor disease activity and as prognostic indicators.

Renal function and hyperfiltration capacity in lead smelter workers with high bone lead.

The study was undertaken to assess whether the changes in urinary excretion of eicosanoids (a decrease of 6-keto-PGF1 alpha and PGF2 and an increase of thromboxane) previously found in lead (Pb) exposed workers may decrease the renal haemodynamic response to an acute oral protein load. The renal haemodynamic response was estimated by determining the capacity of the kidney to increase the glomerular filtration rate (in terms of creatinine clearance) after an acute consumption of cooked red meat (400 g). A cross sectional study was carried out in 76 male Pb workers (age range 30 to 60 years) and 68 controls matched for age, sex, socioeconomic state, general environment (residence), and workshift characteristics. The Pb workers had been exposed to lead on average for 18 (range 6-36) years and showed a threefold higher body burden of Pb than the controls as estimated by in vivo measurements of tibial Pb concentration (Pb-T) (geometric mean 66 v 21 micrograms Pb/g bone mineral). The geometric mean concentrations of Pb in blood (Pb-B) and Pb in urine (Pb-U) were also significantly higher in the Pb group (Pb-B: 430 v 141 micrograms Pb/l; Pb-U: 40 v 7.5 micrograms Pb/g creatinine). These conditions of chronic exposure to Pb did not entail any significant changes in the concentration of blood borne and urinary markers of nephrotoxicity, such as urinary low and high molecular weight plasma derived proteins (beta 2-microglobulin, retinol binding protein, albumin, transferrin), urinary activities of N-acetyl-beta-D-glucosaminidase and kallikrein, and serum concentrations of creatinine, beta 2-microglobulin, urea, and uric acid. All participants also had normal baseline creatinine clearances (> 80 ml/min/1.73 m2) amounting on average to 115.5 in the controls v 121.3 ml/min/1.73 m2 in the Pb group. Both control and Pb exposed workers showed a significant increment in creatinine clearance (on average 15%) after oral protein load suggesting that the previously found changes in secretion of urinary eicosanoids apparently has no deleterious effect on renal haemodynamics in the examined Pb workers. The finding that both baseline and stimulated creatinine clearance rates were not only significantly higher in the Pb workers but also positively correlated with Pb-T, suggests that moderate exposure to Pb may be associated with a slight hyperfiltration state, which has been found to attenuate the age related decline in baseline creatinine clearance by a factor of two. Although the relevance of this effect for the worker's health is unknown, it can be concluded that adverse renal changes are unlikely to occur in most adult male Pb workers when their blood Pb concentration is regularly kept below 700 micrograms Pb/l. One should, however, be cautious in extra-polating this conclusion to the general population because of pre-employment screening of the Pb workers for the absence of renal risk factors.

Early indicators of renal dysfunction in silicotic workers.

The aim of this study was to determine whether silicosis is associated with renal alterations detectable in urinary or blood-borne indicators of nephrotoxicity. The study used a cross-sectional design. The subjects comprised 116 male workers who had been exposed to silica for at least two years and had been diagnosed as having silicosis and 61 age-matched referents. The considered outcome measures were the concentrations of beta, -microglobulin and creatine in serum and the urinary excretion of albumin, retinol-binding protein, and beta-N-acetyl-D-glucosaminidase. Compared with the referents, the silicotic subjects excreted, on the average, slightly higher amounts of albumin, retinol-binding protein, and beta-N-acetyl-D-glucosaminidase. This increase did not correlate with the duration of exposure or the stage of silicosis and was not associated with an elevation in serum creatinine. The concentration of beta2-microglobulin in the serum of silicotic subjects showed a tendency to rise that became significant in the subgroup with pseudotumoral opacities. This effect, which did not correlate with markers of nephrotoxicity, is however more likely the consequence of silicosis-associated inflammatory reactions than of decreased renal filtration. The present study confirms that silicosis is associated with some infraclinical renal alterations. However, in the absence of a relationship with length of exposure or severity of silicosis, the implication of silica in their causation needs to be examined further.

Serum concentration and urinary excretion of beta 2-microglobulin and microalbuminuria in familial Mediterranean fever.

Familial Mediterranean fever is characterised by recurrent and self limited attacks of fever and polyserositis and its devastating complication is the development of renal amyloidosis. In order to detect the presence of early glomerular and tubular damage in patients with familial Mediterranean fever and to assess the possible role of beta 2-microglobulin in the inflammatory attacks of this disease, serum and urine beta 2-microglobulin concentrations and microalbuminuria were evaluated in these patients. A total of 20 patients with familial Mediterranean fever were studied on and off colchicine treatment; seven of these patients developed a familial Mediterranean fever attack when they were off treatment. During the familial Mediterranean fever attacks serum beta 2-microglobulin concentrations decreased, whereas fractional excretion of beta 2-microglobulin, urine beta 2-microglobulin creatinine, and urine albumin/creatinine ratios increased. We conclude that glomerular and tubular functions deteriorate during the attacks. Further studies are needed to discover the effector(s) causing these transient glomerular and tubular disorders.

Clinical Study of High‐Flux Cuprammonium Rayon Hemodialysis Membranes

The aim of this crossover clinical study was to gain basic information on the hemocompatibility and effectiveness of recently developed high-flux membranes made of cuprammonium rayon with ultrafiltration coefficients of 10, 17, and 19 ml/mm Hg/h (S12W, SU12W, and SS12W dialyzers, respectively), and to identify any possible differences from a conventional membrane made of the same material with an ultrafiltration coefficient of 6 ml/mm Hg/h (C12W dialyzer). All the tested membranes led to an abrupt drop in leukocyte count in the initial phase of hemodialysis. In high-flux membranes, C5a anaphylatoxin would pass into the dialysate, but mean C5a anaphylatoxin concentrations in the dialysate were lower by orders of magnitude than its plasma concentrations, which behaved, in high- and low-flux membranes alike, typically of those made of nonsubstituted cellulose with no intermembrane differences. As judged by the concentrations of the thrombin-antithrombin III complex, the coagulation system was activated--again, without differences between membranes. The reduction rates for urea, creatinine, and phosphates were comparable for all the tested membranes. Compared with baseline, the post-dialysis serum concentrations of beta 2-microglobulin in high-flux membranes, unlike the low-flux membrane, were significantly lower. We conclude that there are no significant differences between the tested high- and low-flux membranes made of cuprammonium rayon in the monitored hemocompatibility parameters, and that high-flux membranes are capable of reducing serum beta 2-microglobulin concentrations.

Abnormal renal function in isolated systolic hypertension correlation with ambulatory blood pressure

Does ambulatory blood pressure correlate with the renal function damage better than clinic blood pressure in isolated systolic hypertension, as has been reported in other target organ involvement in combined systolic/diastolic hypertension? We investigated the correlation of serum beta-2 microglobulin concentration and both 24-h urine beta-2 microglobulin concentration and excretion as measures (suggestive) of glomerular filtration rate and tubular reabsorption, respectively with both ambulatory and clinic blood pressure in 19 health normotensive (68 ± 4.9 years) and 50 isolated systolic hypertensive elderly individuals (69 ± 5.4 years). Serum beta-2 microglobulin concentration and 24-h urine beta-2 microglobulin concentration and excretion were higher in the isolated systolic hypertension than in the normotensive group ( P < 0.05). In isolated systolic hypertensive patients, 24-h urine beta-2 microglobulin concentration and excretion were related to ambulatory blood pressure ( r = 0.32–0.40, P < 0.05), but not to clinic blood pressure; waking systolic blood pressure had the strongest correlation with both 24-h urine beta-2 microglobulin concentration and excretion among derivatives of ambulatory blood pressure ( r = 0.35 and 0.40, P < 0.05). We conclude that ambulatory blood pressure, especially waking systolic blood pressure, is superior to clinical blood pressure in predicting renal function impairment, in isolated systolic hypertensive patients.

Nephroprotective effects of nitrendipine in hypertensive type I and type II diabetic patients.

Hypertension is significantly involved in the progression of diabetic nephropathy and in the development of end stage renal disease in both type I and type II diabetes mellitus. We have investigated whether long-term monotherapy with a calcium antagonist, nitrendipine, prevents the development of overt diabetic nephropathy in type I and type II diabetic patients with mild to moderate hypertension and persistent microalbuminuria (ie, incipient nephropathy). After a 4-week run-in and washout period, respectively, 25 patients met the inclusion criteria. Twenty-two patients (six with type I and 16 with type II diabetes) completed the 12-month study. Twelve months of treatment with nitrendipine resulted in a significant reduction in systolic blood pressure in patients with type I (157.5 +/- 8.1 mm Hg v 135.8 +/- 4.2 mm Hg, P < 0.05) and type II (163.1 +/- 4.3 mm Hg v 135.9 +/- 3.6 mm Hg, P < 0.001) diabetes. A significant reduction also was seen in diastolic blood pressure (91.7 +/- 1.7 mm Hg v 79.2 +/- 3.5 mm Hg in type I diabetic patients, P < 0.01; 94.7 +/- 1.4 mm Hg v 78.1 +/- 1.5 mm Hg in type II diabetic patients, P < 0.001). A significant reduction in albuminuria was associated with the blood pressure reduction in both type I (57.8 +/- 11.9 mg/24 hr v 24.9 +/- 5.9 mg/24 hr, -57%) and type II (134.6 +/- 20.7 mg/24 hr v 70.3 +/- 16.8 mg/24 hr, -48%) diabetic patients. The mean glomerular filtration rate increased by 21% (112 +/- 12 mL/min v 135 +/- 14 mL/min) and by 23% (106 +/- 12 mL/min v 130 +/- 14 mL/min) in type I and type II diabetic patients, respectively. No significant changes were found in renal plasma flow rates or in serum concentrations of beta 2-microglobulin. With the exception of a significant (P < 0.05) reduction in hemoglobin A1 concentration in type II diabetic patients after 3 months of treatment with nitrendipine, fasting blood glucose, hemoglobin A1, residual beta-cell function (C-peptide levels), total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, and body mass index remained essentially unchanged during follow-up. These findings suggest that 12 months of monotherapy with the dihydropyridine-type calcium antagonist nitrendipine reduced albuminuria and increased the lowered glomerular filtration rate without adverse effects on glucose and lipid control.(ABSTRACT TRUNCATED AT 400 WORDS)

Renal tubular function after reduction of environmental cadmium exposure: a ten-year follow-up.

A prospective follow-up study was carried out to assess the prognosis of renal tubular function after reduction of environmental cadmium exposure. Time-related changes in urinary beta 2-microglobulin and cadmium excretion were followed from 1979 to 1989 in 102 residents of a cadmium-polluted area in Nagasaki, Japan. The average dietary cadmium intake among the study population was more than 200 micrograms/d in 1969, which decreased to approximately half that amount in 1983 because cadmium-polluted paddy fields were replaced with new soil in 1981. The geometric mean urinary beta 2-microglobulin concentration for 28 subjects aged 40 y or older in 1979 increased from 1,135.8 micrograms/g creatinine in 1979 to 1,999.7 micrograms/g creatinine in 1989. A similar tendency was also observed in 16 subjects with urinary beta 2-microglobulin concentrations greater than 1,000 micrograms/g creatinine in 1979, although the statistical significance of the difference did not reach the 5% level, probably because of the small sample size. In 48 persons examined in 1982, 1986, and 1989, the geometric mean of urinary cadmium concentration decreased from 8.49 micrograms/g creatinine in 1982 to 6.03 micrograms/g creatinine in 1989. The tendency for increasing beta 2-microglobulin excretion observed in the present study could not be explained by aging alone. Thus, it was concluded that renal tubular dysfunction caused by environmental cadmium was irreversible and slowly progressive, even after reduction of exposure. Six of 8 subjects who had severe renal dysfunction and who were included in the study died before 1986 and could not be followed. The implication of loss of subjects because of death is also discussed.

Correlations of peritoneal interleukin-6, serum beta-2 microglobulin and urinary beta-2 microglobulin after elective abdominal surgery.

Postoperative peritoneal interleukin-6 (P-IL-6), serum beta-2 microglobulin (SBMG) and urinary beta-2 microglobulin (UBMG) concentrations were examined in 33 patients who underwent various types of abdominal surgery. Similar time-dependent changes in SBMG and UBMG were observed in five other patients who underwent abdominal surgery. SBMG decreased the first day after the operation (1POD), then increased and reached the preoperative level by the third day after the operation (3POD). UBMG started to increase 1POD, reached the maximum 3POD, then decreased. The 1POD SBMG concentration was significantly correlated with P-IL-6, and 3POD UBMG was also significantly correlated with P-IL-6. These findings indicate that serum and urinary beta-2 microglobulin concentrations are closely correlated with P-IL-6.

Intrathecal synthesis of beta 2-microglobulin and lysozyme: differential markers of nervous system involvement in patients infected with human immunodeficiency virus type 1.

beta 2-Microglobulin and lysozyme were determined in paired serum and cerebrospinal fluid samples from 137 patients, using immunofluorometry and ELISA, respectively. Of these patients, 54 were infected by human immunodeficiency virus type 1 (HIV1) (including 20 AIDS dementia patients), 73 were HIV1-seronegative with neurological diseases (meningitis (n = 10), multiple sclerosis (n = 29), other neurological diseases (n = 34)) and 10 were controls. Intrathecal synthesis of beta 2-microglobulin occurred in each group. Conversely, lysozyme intrathecal synthesis was found only in meningitis (10/10) and in HIV1-infection (24/54). A pathological increase in beta 2-microglobulin intrathecal synthesis (> or = 2 mg/l) was observed in 45 patients (34 HIV1-infected patients and 11 HIV1-seronegative patients with neurological diseases). Serum concentration and intrathecal synthesis of beta 2-microglobulin were correlated only in the 20 AIDS dementia patients. The cerebrospinal fluid beta 2-microglobulin and lysozyme concentrations were correlated in the 54 HIV1-infected patients only. Blood CD4 + T-cell count was correlated negatively with beta 2-microglobulin intrathecal synthesis but not with lysozyme intrathecal synthesis. These data suggest that in the absence of any central nervous system opportunistic process the increase of beta 2-microglobulin intrathecal synthesis (> or = 2 mg/l) may be a reliable marker of central nervous system involvement in HIV1-infected patients. Intrathecal synthesis of lysozyme was related principally to HIV1-encephalitis and central nervous system opportunistic processes.

Biocompatibility of a new high-permeability modified cellulose membrane for haemodialysis

The biocompatibility and solute permeability characteristics of a high-permeability modified cellulose membrane (Hemophan-HP) (He-HP) were compared with those of two synthetic membranes (poly(ethylene-co-vinyl alcohol) (EVAL) and poly(acrylonitrile-co-sodium methallyl sulphonate) (AN69)) and Cuprophan in a multicentre, four-way cross-over clinical trial. Cuprophan membranes caused significant complement activation, leukopenia, and granulocyte elastase release. He-HP membranes demonstrated a lesser effect, which was similar to that observed for the EVAL membrane, although less than that seen with the AN69 membrane. A similar order for the four membranes was seen for their effect on platelets. Cuprophan membranes provided superior small-molecule removal to the other three membranes. In contrast, Cuprophan was essentially impermeable to beta 2-microglobulin, whereas He-HP, EVAL, and AN69 allowed the removal of 60-90 mg of beta 2-microglobulin per treatment. However, a decrease in the plasma concentration of beta 2-microglobulin was observed only with the AN69 membrane, most probably as a result of the ability of that membrane to adsorb proteins. Our results demonstrate that high-permeability membranes of comparable biocompatibility to some synthetic membranes can be fabricated from cellulose derivatives.

Determination of β2-Microglobulin in Serum by a Microparticle-Enhanced Nephelometric Immunoassay

This fully automated nephelometric immunoassay to quantify beta 2-microglobulin in human serum measures the light-scattering signal produced by agglutination of commercially available latex microparticles (diameter 0.1 micron) coated with specific F(ab')2 against beta 2-microglobulin. The calibration curve, generated by serial dilutions of a beta 2-microglobulin standard of known concentration, is used to calculate beta 2-microglobulin concentrations in serum samples by the logit-log function and linear-regression analysis. The assay range (sample dilution 400-fold) extends from 0.3 to 40.0 mg/L. No antigen excess appears at beta 2-microglobulin concentrations up to 320 mg/L. Within-run CVs ranged from 1.0% to 3.4%, and between-days from 1.2% to 2.8%. Total imprecision (CV) was < 5%. Analytical recovery averaged 99.5% +/- 2.8%. Rheumatoid factor, complement, bilirubin (up to 340 mumol/L), and hemoglobin (up to 2.0 g/L) do not interfere. Strongly turbid lipemic samples must be cleared before analysis. Standard curve linearity was very good in samples covering the clinical useful range of concentrations. Results of the method correlated well with those of radioimmunoassay and microparticle enzyme-linked immunoassay (r = 0.979 and 0.975, respectively). The reference interval (nonparametric estimation) in apparently healthy adults (n = 303) was 0.87 (0.80-0.94) to 2.42 (2.28-2.45) mg/L; the median value was 1.54 mg/L.

Serum protein concentrations in Plasmodium falciparum malaria

In patients with uncomplicated Plasmodium falciparum infection cytokine-mediated serum protein levels of C-reactive protein (CRP), coeruloplasmin (COE), beta 2-microglobulin (B2M), alpha 1-acid glycoprotein (AAG), alpha 1-antitrypsin (AAT), haptoglobin (HPT), prealbumin (PRE), retinol binding protein (RBP), albumin (ALB) and transferrin (TRF) were measured in an endemic area of the Amazonian rain forest. Semi-immune (SI) and nonimmune (NI) patients were investigated. In both patient groups the serum concentrations of CRP, COE and B2M were elevated on admission. In addition AAG and AAT concentrations were increased in NI patients compared to control subjects. Significantly lower serum concentrations of HPT, PRE, RBP, ALB and TRF were seen in both patient groups during the acute phase of the disease, and were more pronounced in NI patients. After a 28-day follow-up, AAT and B2M were normal in SI patients but HPT, AAT and B2M were still significantly altered in NI patients.

Impairment of vitamin D metabolism due to environmental cadmium exposure, and possible relevance to sex-related differences in vulnerability to the bone damage.

To determine whether depleted serum 1 alpha,25-dihydroxyvitamin D (VD) concentrations are associated with cadmium (Cd)-induced renal damage, the relationships between four indices of renal function and two indicators of bone metabolism, that is, serum VD and parathyroid hormone (PTH) concentrations, were analyzed in 30 male and 44 female subjects exposed to environmental Cd. Also, these associations were compared in male and female subjects to evaluate sex-related differences in vulnerability to the bone damage observed in Cd-exposed persons. Serum VD decreased significantly with declines in creatinine clearance and percentage tubular reabsorption of phosphate, and with increases in serum creatinine and serum beta 2-microglobulin (beta 2m) concentrations in the female subjects exposed to Cd, but not in the male subjects. The correlation between serum VD and PTH levels was also significant only in the females. Correlation coefficients between serum beta 2m and VD and those between serum PTH and VD in both sexes were significantly different. These results suggest that renal damage due to Cd exposure leads to the decreases in the serum VD level and increases in serum PTH level, and that the more marked changes in serum VD and PTH in the women may play a role in the development of sex-related differences in Cd-induced bone injury.

Follow up study of renal tubular dysfunction and mortality in residents of an area polluted with cadmium.

A retrospective cohort study was conducted to investigate the association between cadmium induced renal tubular dysfunction and mortality. A total of 230 subjects aged 40 or older and living in a cadmium polluted area in Kosaka Town, Akita Prefecture, Japan, were studied at least once between 1975 and 1977 and again in 1990. Urinary beta 2-microglobulin and total amino nitrogen concentrations were significantly related to mortality from all causes in women. The finding supports the idea that cadmium induced kidney damage is a factor associated with mortality in a general population exposed to environmental cadmium.

Patterns of Serological Markers for Cellular Immune Activation in Patients with Dilated Cardiomyopathy and Chronic Myocarditis

We determined serum concentrations of neopterin and beta 2-microglobulin, soluble markers of cellular immune activation, in 27 patients with either dilated cardiomyopathy (DCM) or chronic myocarditis. Neopterin and beta 2-microglobulin concentrations were respectively increased in 2 and 5 of 11 patients with DCM and in 11 and 9 of 16 patients with chronic myocarditis. A higher cardiac functional class (according to the New York Heart Association) was associated with greater neopterin and beta 2-microglobulin concentrations. During follow-up of patients, both neopterin and beta 2-microglobulin concentrations in serum correlated with the course of disease. Additionally, correlations were significant between left ventricular functional tests (end-diastolic volume, end-systolic volume, and ejection fraction) and neopterin and beta 2-microglobulin concentrations. We conclude that measurement of neopterin and beta 2-microglobulin are useful to monitor disease development in patients with myocardial inflammation.

Prolonged interferon-gamma application by subcutaneous infusion in cancer patients: differential response of serum CD14, neopterin, and monocyte HLA class I and II antigens.

This study reports on biological response modification induced by prolonged continuous subcutaneous (s.c.) infusion of recombinant interferon-gamma (rIFN-gamma) with particular attention to changes of soluble CD14. This glycoprotein with an unknown function is derived from myeloid cells carrying membrane CD14, which is the receptor for lipopolysaccharide (LPS)-LPS-binding protein (LBP) complexes. Fifteen metastatic cancer patients received weekly escalating doses of rIFN-gamma starting at either 50 or 100 micrograms/24 h and increasing up to 400 micrograms/24 h for a median duration of 6 weeks. The maximum tolerated dose was higher (200 micrograms/24 h) with the lower (50 micrograms/24 h) starting dose. Biological activity of rIFN-gamma was evaluated by weekly measurements of CD14, neopterin, and beta 2-microglobulin concentrations in serum as well as monocyte HLA class I and II antigen expression and tumor cytotoxicity. Serum IFN-gamma concentrations increased 20-fold within 4 weeks of therapy. The levels were correlated to the mean dose (r = 0.95, p less than 0.05). Among the biological markers, two patterns were observed. First, serum CD14 concentration and expression of monocyte HLA class II antigens increased significantly during the first week, and marker expression correlated with serum IFN-gamma levels (p less than 0.05); CD14 and HLA class II antigens thereafter returned to pretreatment levels within 4 weeks of therapy despite persistently elevated serum IFN-gamma concentrations. Second, serum neopterin and beta 2-microglobulin concentrations as well as monocyte HLA class I expression also increased significantly within the first week, but remained elevated thereafter without any further dose relationship.(ABSTRACT TRUNCATED AT 250 WORDS)

Measurement of ?2 microglobulin in dried urine spotted on filter paper by means of a forward sandwich enzyme-linked immunosorbent assay

We devised a highly sensitive forward sandwich enzyme-linked immunosorbent assay (ELISA) for estimation of the beta 2-microglobulin concentration in dried urine spotted on filter paper. This method is suitable for mass screening because of the good reproducibility, satisfactory stability, low operation cost and easy sample collection. However, preliminary studies using our new method for detecting renal diseases in the Tokyo infant population did not produce good results. The high cut-off value may have been the main reason. To make this ELISA more suitable for mass screening, we plan to reduce the cut-off value, test older children and improve the extraction step.

Assessment of occupational exposure to cadmium in The Netherlands, 1980-1989.

One thousand five hundred fifty urine samples and 1,295 blood samples, collected from 919 workers, were analyzed for cadmium (Cd). The workers were employed at 16 different types of workplaces. In about 7.5% of the samples, the concentration of Cd exceeded the biological limit values proposed by the Dutch Expert Committee for Occupational Standards. Levels higher than these values were measured in both urine samples and blood samples of workers involved in electrochemical plating, in production of Cd-stabilizers and enamels, and in soldering with silver-cadmium solder. Significantly higher concentrations of beta 2-microglobulin (MG) were found in urine samples with CdU greater than 10 micrograms/g creatinine. Cd levels in urine increased with age.

Failure of a daily haemofiltration programme using a highly permeable membrane to return beta 2-microglobulin concentrations to normal in haemodialysis patients.

In an attempt to return to normal serum beta 2-microglobulin levels in a group of seven ESRD patients, a programme of daily HF with highly permeable AN69 membranes was undertaken. Pre-HF beta 2-M serum levels stabilized after 4 days at 20 mg/l, only 40% lower than the initial concentration. A total of 985 +/- 20 mg beta 2-M was removed over the week. The beta 2-M release rate averaged 97 micrograms/min with a broad range of values (63-128 micrograms/min). beta 2-M release peaked at 602 micrograms/min 1 h after the end of the HF session before returning to baseline by 12 h post-HF. We conclude that a return to normal blood beta 2-M concentrations in ESRD patients seems quite unrealistic despite a highly intensive extracorporeal therapy. Therefore other therapeutic alternatives have to be designed to prevent or cure beta 2-M amyloidosis.