An automated chemiluminescence immunoassay may detect mostly relevant IgG anticardiolipin antibodies according to revised Sydney criteria.

BACKGROUND: Detection of anticardiolipin antibodies (ACA) is an independent laboratory criterion for diagnosis of antiphospholipid syndrome (APS). Alternative methods to ELISA were recently developed such as automated chemiluminescence immunoassay (CLIA). PATIENTS AND METHODS: We compared a CLIA to an ELISA kit for the detection of IgG isotype of ACA. 87 routine samples from 75 patients suspected of having APS were tested using each method. Cut-off values were calculated in our laboratory for each test using 99th percentile of 50 normal controls. RESULTS: Cut-off values were >20 GPL for ELISA and > 2 GPL for CLIA. Overall agreement (OA), agreement for positive (AP) and agreement for negative (AN) cases were 56.3%, 49.2% and 77.2% respectively. Most discrepant results were positive with ELISA and negative with CLIA. However, OA, AP and AN increased to 82.1%, 84.6% and 80% respectively when CLIA was compared to the repeated ELISA performed at least 12 weeks later. When correlated with APS-related clinical background, CLIA showed lower sensitivity, higher specificity and higher likelihood ratio (LR) as compared to first ELISA whereas these parameters were similar to those of the repeated ELISA. No association was found between any test results and APS-related clinical background of the patients. Using our own cut-off value (> 2GPL), sensitivity, specificity and LR of CLIA to identify patients with APS were respectively 100%, 72.3% and 3.6. A ROC curve showed that at 7.5 GPL cut-off value, specificity and LR improved to 91.1% and 11.25 respectively, without affecting sensitivity. A strong correlation was observed between CLIA results and APS (Chi2 = 12.25; p < 0.001). CONCLUSION: The performance of CLIA is as good as a repeated ELISA test to detect IgG ACA in suspected APS patients. It is fully automated, which represents several advantages over semi-manual ELISA techniques for its implementation in a routine laboratory.

Longitudinal study of bone metabolism after ethanol withdrawal in alcoholic patients.

The pathogenesis of osteopenia in chronic alcoholism remains unclear, and many ethanol-related abnormalities have been advocated to explain bone loss. A direct inhibitory effect of ethanol on osteoblast function was suggested by in vivo and in vitro studies. We measured biochemical markers of bone turnover in 12 alcoholic men before and during a 2 week period of alcohol withdrawal, and we compared the results with those obtained in 15 nonalcoholic men. Our alcoholic patients presented with (1) decreased serum concentrations of bone gla protein (BGP), suggesting decreased bone formation; (2) increased urinary excretion of hydroxyproline, suggesting increased bone resorption; (3) increased renal threshold of phosphate excretion without modification of serum PTH concentration, suggesting a direct effect of ethanol on the renal handling of phosphate. The rapid increase in serum BGP concentrations following ethanol withdrawal suggests that low serum BGP concentrations in alcoholics may result from a direct toxic effect of ethanol on osteoblast function and/or numbers.

Comparative study of the changes in insulin-like growth factor-I, procollagen-III N-terminal extension peptide, bone Gla-protein, and bone mineral content in children with Turner's syndrome treated with recombinant growth hormone.

Six girls (7-13 yr old) with Turner's syndrome and short stature were treated for 1 yr with recombinant human GH (0.15 U/kg.day, sc) and had sequential determinations of serum insulin-like growth factor-I (IGF-I), osteocalcin, and procollagen-III. Bone mineral content and density of the spine and radius were measured before treatment and at 90 and 360 days. Two girls received small doses of ethinyl estradiol (0.025 micrograms/kg) in addition to GH. Height velocity increased by 144% after 3 months of treatment. IGF-I was normal (0.75 +/- 0.20 kU/L) before treatment and increased by 90% on day 1 and by 290% on day 360. Procollagen-III was low before treatment; it peaked at 53.0 +/- 14.7 micrograms/L (260% above baseline) on day 30, then decreased to the normal range. Serum osteocalcin increased more slowly to reach a plateau on day 90 of 23.7 +/- 1.2 micrograms/L (46% above baseline). Before treatment, bone mineral content of the spine was 25% lower than that of children matched for bone age. Bone mineral contents of the peripheral and axial skeleton were increased by 10% and 17%, respectively, after 1 yr of treatment, an increase commensurate with that of bone age in the four patients who did not receive estrogen. On day 90, however, although radius mineral density was already increased by 3%, the mineral density of the lumbar spine was significantly decreased by 4%. We conclude that treatment with GH increases IGF-I, collagen turnover, osteoblastic function, and height velocity in Turner's syndrome. However, there is no catch-up of bone mineral content after 1 yr of treatment, and an early effect of GH is to decrease spine mineral density.

Inhibition of puerperal lactation by means of a single injection of bromocriptine retard.

The efficacy, tolerance and acceptability of a single i.m. injection of 50 mg bromocriptine retard (in polylactic acid microspheres), given within 12 h after delivery for suppression of lactation, were investigated in 47 mothers not willing to breast-feed. Slight to moderate breast discomfort was noticed during the first postpartum days in 23% of the patients but lactation was indeed prevented in all cases and no rebound lactation occurred in any case. Only six patients exhibited at least two symptoms of mammary engorgement (congestion and pain or milk let-down): in this group, blood mean PRL levels were significantly less suppressed on postpartum days 2, 6, 21 and 28 (p less than 0.05 to p less than 0.001) than in the group of mothers completely free of any mammary symptoms. Slight side-effects (mostly dizziness), as mentioned at systematic request, were recorded in 34% of the patients; only 3 patients required treatment for their side-effects. Recovery of ovarian function was evident quite early (by day 28 in 72% of the patients), thus requiring early onset of contraception.

Relative contribution of various expressions of cAMP excretion to other indices of parathyroid function, as tested by discriminant multivariate linear regression analysis.

We evaluated the relative contribution to the diagnosis of hyperparathyroid disease from current laboratory indices of parathyroid function--plasma calcium (I), phosphate (II), carboxy-terminal (III) and predominantly amino-terminal (IV) radioimmunoassays of parathyrin, the urinary excretion ratios of cyclic adenosine monophosphate (cAMP) to creatinine (V) or to glomerular filtrate (VI), and the ratio of the nephrogenous fraction of cAMP to glomerular filtrate (VII)--in 224 subjects: 40 with surgically proven hyperparathyroid disease, the others normoparathyroid. The decreasing order of sensitivity was I greater than VI greater than VII greater than V greater than III greater than IV greater than II; all these indices differed significantly between normoparathyroid and hyperparathyroid patients. The decreasing order of specificity was VII, III greater than I greater than IV greater than V, II greater than VI. Discriminant multivariate linear regression analysis was performed in a subset of 58 subjects (17 hyper- and 41 normoparathyroid) from the population studied here, chosen because all of the laboratory indices were determined for each subject. The classification accuracy was 98.3% for combining I, VII, and III (r = 0.908), or I and V (r = 0.893), or I and VII (r = 0.889). The other variables did not add to the precision of classification.

Plasma beta 2 microglobulin as a means of predicting gentamicin serum concentrations.

A novel and accurate method for predicting gentamicin peak serum concentration is described. The method considers body weight and renal function as determined by the concentration of beta 2 microglobulin in plasma. In 32 subjects whose renal function ranged from normal to severely impaired, the peak serum concentration of gentamicin was more closely correlated with beta 2 microglobulin (r = 0.69) and with creatinine clearance (r = 0.69) than with serum creatinine (r = 0.53). A nomogram was constructed which related plasma beta 2 microglobulin concentrations and body weight to predicted gentamicin peak serum concentrations. When the nomogram was clinically applied, the predicted peak gentamicin concentrations corresponded closely to the actual measurements obtained (t = 0.64; P is not significant). We suggest that plasma beta 2 microglobulin concentrations compare favorably with serum creatinine values in the prediction of gentamicin peak concentrations in patients with renal impairment.

[beta2-Microglobulin in renal transplanted patients (author's transl)]. / La beta2-microglobuline plasmatique chez les transplantés rénaux.

Plasma beta2m has been measured frequently during long term follow-up of kidney transplanted outpatients. The ratio of beta2m/log creatinine was abnormally high in 15 patients of this series bearing a symptomatic hepatitis independently of any modification of immunodepressive drug administration schedule (azathioprine and corticoids). The true effect of azathioprine could not be isolated whereas corticotherapy modified clearly the beta2m/creatinine ratio : increase of dosage for rejection resulted in a fall of the ratio whereas fast reduction increased the ratio acting essentially on circulating beta2m level (12 cases). The beta2m/creatinine ratio was normal or occasionally diminished in the 22 patients having an uneventful clinical course. Six patients showed mixed effects of hepatitis and variation of corticoid dosage and 7 cases were too much intricated to permit a good analysis of the data.