Measuring urinary protein with the new BioRad reagent kit: evaluation and comparison with five other methods.

Total urinary protein was measured by five methods: BioRad Total Protein Test (TPT), pyrogallol red, benzethonium chloride, sulfosalicylic acid, trichloroacetic acid, and the results compared to those obtained by a method combining preparative ultrafiltration and the biuret reaction. TPT was linear to 1.5 g protein/l, the detection limit 0.0135 g/l, and it was 3-5 times more sensitive than the other methods. Within-day precision (CV) was 4.3%, (0.60 g/l), the day-to-day precision was 4.5%. The protein contents of 35 selected urine samples assigned to one of five groups according to their electrophoretic pattern were assayed by the five methods. No method accurately measured physiological proteinuria, but the values for light chain (Bence Jones), glomerular, tubular and overload proteinurias measured by TPT did not differ significantly from the biuret value. The other methods differed significantly for at least three groups. Alpha 1 acid glycoprotein slightly inhibited TPT, but peptones, amino acids, antibiotics or normal urine constituents had little or no effect. The TPT method has been automated (Kone Progress); normal 24-h urinary protein excretion was 36 mg/day (range 12-114), the protein creatinine ratio was 34 mg/g (12-106 mg/g).

[Immunoelectrophoresis or immunofixation: identification of monoclonal gammopathy]. / Immunoélectrophorèse ou immunofixation: identification d'une gammapathie monoclonale.

Both methods enable the clinical laboratory to identify monoclonal gammapathies with a good sensitivity. The immunofixation method, more quickly used than the immunoelectrophoresis, is easier to obtain the best resolution. It is well adjust for the characterization of low concentration gammapathies like immunoglobulin light chains. Immunofixation appears to take a more and more important place in the clinical laboratory.

Optimized microturbidimetric assay for fibrinogen.

In this assay we measure the turbidity produced by precipitation of plasma fibrinogen with a reagent composed of ammonium sulfate, EDTA, and guanidine hydrochloride. The two-step reagent addition, and use of fixed reaction times, eliminates interference from bilirubin, hemoglobin, and chylomicrons. We checked 135 monoclonal proteins for interference, finding the probability of encountering major interference in samples from adults to be very low, P = 0.0002. The method is calibrated with purified fibrinogen and the response is linear over the range 0-10 g/L. Within-run precision (CV) is less than 2% from 1 to 10 g/L. Correlations with the immunoturbidimetric (r = 0.99), chronometric (r = 0.99), and clotting (r = 0.97) methods were extremely high.

Nosocomial outbreak of Campylobacter jejuni meningitis in newborn infants.

In a nosocomial outbreak of Campylobacter jejuni infection 11 newborn infants (7 female, 4 male) had meningitis. The outbreak was caused by a single strain of C jejuni, as demonstrated by biotyping (biotype I), serotyping (LAU 7/PEN 18 on heat-stable antigens, a new serotype on heat-labile antigens), and the identical susceptibility pattern and outer-membrane-protein profile on sodium dodecyl sulphate/polyacrylamide gel electrophoresis. Specific antibodies against the outbreak strain (enzyme-linked immunosorbent assay and Western blot) developed in all the babies. They were treated with gentamicin and ampicillin. All but one baby, who had a moderately dilated left lateral ventricle after the meningitis, recovered well. The source of infection could not be clearly determined. Thus, C jejuni can cause serious nosocomial infection; it should be considered as a possible agent of meningitis of unknown origin, particularly in newborn infants and other compromised hosts.

Is standardization more important than methodology for assay of total protein in cerebrospinal fluid?

Four manual micromethods for protein determination, two turbidimetric (trichloroacetic and sulfosalicylic acid-sodium sulfate) and two colorimetric (Lowry and Coomassie Brilliant Blue--sodium dodecyl sulfate, CBB-SDS) were used to compare the standard curves for total protein (0.30 to 3 g/L) produced with three reference materials: bovine serum albumin, human serum albumin, and diluted human serum. We measured the apparent protein content of a sample of pooled human cerebrospinal fluid by all four methods and with use of all three standards. The only reference material that gave similar results with all four methods was diluted human serum; the CBB-SDS was the only method that gave identical results with all three reference materials. We then measured the protein concentration of 28 individual cerebrospinal fluid samples by the four methods, with diluted human serum as standard. Results by all methods correlated well, but only the sulfosalicylic acid and the CBB-SDS methods gave equivalent results. We conclude that the choice of standard is more important than the method used. However, the CBB-SDS method may be the preferred method because it produced identical standard curves with all three protein standards.

[Serum creatine kinase in normal newborns (author's transl)]. / Quelle valeur faul-il accorder au dosage do la créatine kinase chez le nouveau-né.

Serum creatine kinase activity (CK) in 82 normal newborns was found to be significantly higher the 2nd day than the values found in the cord blood and on the 5th day after birth. Higher values were observed when labor was induced by oxytocin stimulation and following breech delivery where they could reach a level up to 40 times normal. No definite relationship was noted between the enzyme level at 2 days of age and the duration of the various stages of delivery. We conclude that, because of the increased CK activity found in normal newborns, screening for Duchenne muscular dystrophy should hence be postponed at least 5 days after delivery.

[Turbidimetric micromethod for estimation of fibrinogen (author's transl)]. / Microméthode turbidimétrique de dosage du fibrinogène.

A turbidimetric micromethod for estimation of fibrinogen, both manual and by automatic analysis, is described. It is based on the use of a reagent containing ammonium sulphate, EDTA and glycerol. The blood may be collected either on heparin, EDTA or trisodium citrate. The correlation with the weight methods (r = 0,980), chronometric methods (r = 0,939) and immunonephelemetric methods (r = 0,985) permits its use as a routine method.

[Simultaneous discovery of a malignant histiocytosis in a newborn and a preleukemic syndrome in his mother (author's transl)]. / Découverte simultanée d'une hémopathie maligne chez un nouveau-né et d'un syndrome préleucémique chez la mère.

A malignant histiocytosis in a newborn was found at the same time than a preleukemic syndrome in his mother (less than 10% myeloblasts with Auer rods). An overt myeloblastic leukemia occurs in the mother in the next four months. This uncommon association was presented and discussed.

[Micromethod of estimation of total bilirubin using a single stable reagent (author's transl)]. / Microméthode de dosage de la bilirubine totale utilisant un réactif unique et stable.

The authors propose a method of estimation of total bilirubin characterised by the use of a single stable reagent, excellent reproducibility and a particularly narrow correlation (r = 0.993) with Michaelsson's method. They study the influence of protein, reduced glutathion and hemoglobin on the reaction.

[Adaptation to the Centrifichem of the estimation of blood sugar according to Trinder's method. Kinetic study of the main drug interferences (author's transl)]. / Adaptation au Centrifichem du dosage de la glycémie selon Trinder. Etude cinétique des principales interférences médicamenteuses.

The method of estimation of glucose described by Trinder was adapted to analysis by centrifugation (Centrifichem). A kinetic study of drug interferences (ascorbic acid, gentisic acid, levodopa, alphamethyldopa) was carried out. The choice of parameters of the method was justified by an increased specificity of the reaction and by an extremely narrow correlation with the technics using hexokinase (r = 0.994) and glucose dehydrogenase (r = 0.996).