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).

Determination of erythrocytic polyamines by reversed-phase liquid chromatography.

A simple and rapid semiautomated procedure for determining polyamines in erythrocytes by high-performance liquid chromatography is described. Putrescine, spermidine, and spermine are converted to fluorescent dansyl derivatives, extracted with cyclohexane, and separated in less than 10 min on a reversed-phase C18 ODS column, with an acetonitrile-water gradient as the mobile phase. The method showed a coefficient of variation of 2.73% for spermidine and 3.27% for spermine. The respective reference values, evaluated in 10 healthy patients, were 7.88 (SD 2.09) and 5.42 (SD 1.55) mumol/L of packed erythrocytes. Only negligible amounts of putrescine were found.

Persistent elastase/proteinase inhibitor imbalance during prolonged ventilation of infants with bronchopulmonary dysplasia: evidence for the role of nosocomial infections.

Acute imbalance between elastase and alpha-1-proteinase inhibitor (alpha 1Pi) may contribute to the development of bronchopulmonary dysplasia (BPD). The question of whether such an imbalance persists in BPD infants still requiring mechanical ventilation after 4 wk of life has not been previously addressed. We studied 14 infants still on mechanical ventilation at 4 wk of age: nine had BPD and five did not. Weekly (4 to 9 wk) serum and bronchoalveolar lavage (BAL) specimens were taken. alpha 1Pi and alpha-2-macroglobulin were measured in serum and BAL by immunoturbidimetric assay. BAL elastase activity was measured by cleavage of a synthetic substrate and expressed as ng of porcine pancreatic elastase equivalent. Infants with BPD had higher levels of serum alpha 1Pi and alpha-2-macroglobulin than those without BPD. In contrast, the corresponding BAL levels were either similar or even decreased (alpha 1Pi). Moreover, there was a 3-fold increase in elastase-1Pi imbalance expressed as the BAL ng of porcine pancreatic elastase equivalent/2 alpha 1Pi ratio. The role of nosocomial infections was evident in a subgroup of 11 infected BAL aspirates in BPD infants. In such cases we found a 3-fold increase in the BAL ng of porcine pancreatic elastase equivalent/alpha 1Pi ratio as compared to 35 noninfected BAL in BPD infants. These data suggest a persistent alveolitis with imbalance between elastase and proteinase inhibitors in prolonged severe BPD. Such an imbalance is, in part, explained by a local destruction and/or inactivation of alpha 1Pi. Our results also emphasize the increase in proteolysis with nosocomial pneumonia.

[Cerebrospinal fluid lysozyme in meningitis in children. Value in establishing the etiologic diagnosis]. / Le lysozyme du liquide céphalo-rachidien au cours des méningites de l'enfant. Intérêt dans l'orientation du diagnostic étiologique.

Cerebrospinal fluid lysozyme (CSF-LZM) concentrations were determined in 62 controls, 28 viral meningitis and 22 bacterial meningitis, as compared to CSF lactic acid routinely used. CSF-LZM measurement was performed by a rapid turbidimetric assay which required 50 microliters CSF only. The mean CSF-LZM concentration of the control group was 0.23 mg/l, the highest value being 0.65 mg/l. The mean LZM levels in viral meningitis were 1.10 mg/l, never exceeding 3 mg/l. The range of pretreatment LZM levels in bacterial meningitis was 7.2 to 65 mg/l and above 3 mg/l in all cases 48 h after treatment. On the 6th day after admission, 12 of 16 samples showed abnormal values. The CSF-LZM assay seems to be of more value than that of lactic acid. Thus, before treatment, LZM concentrations were 10 to 100 fold higher than that of the normal values, with persistent high levels on the 2nd and even on the 6th day of treatment (whereas lactic acid values were all normal on day 6).

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.

Clearance of compounds of different molecular size in the human placenta in vitro.

The placental clearance of selected water-soluble molecules and antipyrine was evaluated using a dual perfusion of human placental lobules in vitro. When graded according to decreasing clearance, the sequence of the molecules was as follows: water = antipyrine greater than urea greater than p-aminohippuric acid greater than inulin greater than dextran 20 greater than dextran 70. A close correlation was obtained between the clearance and the free diffusion coefficient of these molecules. However, no restricted diffusion was observed in the molecular range studied. These results suggest an equivalent pore size larger than 90 A for the human placental membrane in vitro.

[Nosological aspects of epilepsia partialis continua in children]. / Aspects nosologiques des épilepsies partielles continues chez l'enfant.

Among 26 patients suffering from Epilepsia Partialis Continua, 2 major groups were observed. The first, resulting from a fixed lesion of the rolandic area, showed electro-clinical correlation of seizures; the latter disappeared during sleep; clinical and radiological follow-up failed to disclose any worsening of the cerebral lesion. The second group was characterized by progressive mental and motor deterioration, lack of electro-clinical correlation of fits, persistence of the latter during sleep and frank increase of cerebral atrophy observed on serial neuroradiological examinations. This easily recognized group seems to result from a progressive inflammatory disease of unknown cause.

[Herpetic encephalitis in infants and children. Methods of diagnosis]. / Encéphalites herpétiques du nourrisson et de l'enfant. Méthodes de diagnostic.

Thirteen infants and 2 children with Herpes simplex encephalitis are reported and the authors emphasize the diagnostic value of several investigations: the neurological examination (fits followed by early motor deficit on the same side and coma), the EEG (periodicity and asymmetry of the trace), the CT scan (hypodensity in the frontotemporal areas), the level of the Interferon alpha in blood and cerebrospinal fluid, the electrophoretic pattern of cerebrospinal fluid proteins and the comparative study of cerebrospinal fluid/serum antibodies towards several viral antigens.

[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.

[The pattern of cerebrospinal fluid proteins in infants and children. Determination of normal values (author's transl)]. / Profil protéique du liquide céphalo-rachidien chez l'enfant. Détermination des limites de référence.

Cerebrospinal fluid (CSF) protein values were measured in 652 children between the ages of 1 day and 17 years, allowing the authors to define the dynamics of the blood-brain barrier under normal conditions and during inflammation of the nervous system. The ratio of CSF albumin/serum albumin (whose upper limit was 0.65 in the study) was the best sign of alteration of blood-brain barrier permeability. The CSF IgG level, whose upper limit was 0.85 (for serum IgG between 10 and 14 g/l) is the most useful criterion for detecting an intra-thecal synthesis of IgG. Six patterns of CSF proteins are defined on the basis of immunochemical and electrophoretic studies. The ratio of CSF albumin/serum albumin and the CSF IgG level must be compared to the electrophoretic pattern of CSF proteins in order to better characterize one aspect of the blood-brain barrier under normal and pathologic conditions of the central nervous system.

[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.