Assessment of the stability of teicoplanin in intravenous infusions.

The advance preparation of intravenous solutions of teicoplanin, which is often used in antibiotic infusions for hospitalized patients, may be advantageous. The objective of this study was to investigate the stability of teicoplanin stored at 4 deg C in polyvinyl chloride bags to determine whether such solutions could be safely stored without deterioration. Five bags containing 0.4g teicoplanin per 100 mL of 5 % dextrose injection were studied for 1 month by means of high-performance liquid chromatography, visual inspection, and pH measurement. The color of teicoplanin diluted in dextrose became slightly yellow, and the pH values of the preparations decreased significantly during the period of the study without affecting the chromatographic parameters. The teicoplanin solution was stable for 6 days at 4 deg C as a result of the shortest shelf life of 90% residual potency of the five major glycopeptide components. Despite the color and pH variations, the teicoplanin infusion remained chemically stable when stored up to 6 days at 4 deg C in polyvinyl chloride bags. Thus the infusion could be prepared in advance by a centralized intravenous admixture service for use within the limits described.

Particle counting immunoassay for urinary cotinine. Comparison with chromatography, enzyme-linked immunoassay and fluorescence polarization immunoassay.

Urinary cotinine was measured according to its inhibitory activity on the agglutination of cotinine-coated latex particles by anti-cotinine antibodies, the agglutination being measured by optical counting of the remaining non-agglutinated particles (particle counting, PaC). The detection limit was 0.03 microgram/ml and the practical range extended from 0.03 to 3.9 micrograms/ml. The correlation results of 320 urine samples with those of high pressure liquid chromatography, enzyme-linked (Coti-Tracq EIA, Serex Inc., Maywood, NJ, USA), and fluorescence polarization immunoassay (TDX instrument, Abbott, Abbott Park, IL, USA) were r = 0.90, r = 0.69, r = 0.87, respectively, whereas the correlation coefficients between the assays other than particle counting ranged from 0.62 to 0.88. PaC does not require any separation step and can thus be easily automated.

Tobacco smoking and alcohol and drug consumption in a large, young healthy population.

The relationships between tobacco smoking and both alcohol and drug consumption were investigated in 2 431 healthy individuals aged 18-29 y. We used a questionnaire to evaluate smoking habits and alcohol and drug intake, and these parameters (i.e., cotinine-to-creatinine concentration ratio, amphetamines, cannabinoids, opiates, and cocaine) were quantified via urine analyses. Urinary cotinine concentration was significantly higher in current smokers (mean +/- standard deviation: 717 +/- 61 ng/mg creatinine, n = 881) than in non- or exsmokers (32 +/- 16 ng/mg creatinine, n = 1550). Information gleaned from the questionnaires revealed that there was a greater proportion of current smokers among consumers of alcohol than among nonconsumers. Significantly (p < .001) more current smokers than non- or exsmokers self-reported that they consumed sedatives, stimulants, or illegal drugs. Urinary cotinine concentrations were highest in consumers of alcohol and in self-reported consumers of sedatives (p < .0001), stimulants (p = .01), and illegal drugs (p < .0001). We found higher urinary cotinine concentrations in subjects who had positive urinary amphetamines, cannabinoids, or opiates. Even though the prevalence of alcohol and drug consumption remained low in the population we studied, such behaviors were clearly related to tobacco smoking.

Particle counting assay for anti-toxoplasma IgG antibodies. Comparison with four automated commercial enzyme-linked immunoassays.

An assay for anti-toxoplasma IgG antibodies based on agglutination of latex particles was set up and compared with commercial immunoassays. The reaction was measured by instrumental counting of particles remaining unagglutinated. The running time was 45 min. This test (PaC) was compared using 243 serum samples with four automated commercial immunoassays: the Enzymum test Toxo IgG (ES300, Boehringer), the Vidas Toxo IgG (Biomérieux), the IMX Toxo IgG (Abbott), the Magia Toxoplasma gondii IgG (Merck). The mean values (+/- SD) obtained by IMX (25 IU +/- 68) and ES300 (45 IU +/- 142) were significantly lower than the values obtained by Vidas (73 IU +/- 237, p < 10(-4) and p = 0.006, respectively), by Magia (80 IU +/- 300, p < 10(-4) and p = 0.0005) and by PaC (70 IU +/- 260, p < 10(-4) and p = 0.0126). The correlations between PaC and Toxo IgG Boehringer, Biomérieux, Abbott, Merck were r = 0.97, r = 0.98, r = 0.94, r = 0.98, respectively. The correlation coefficients between the enzyme-immunoassays ranged from 0.96 to 0.99. All positive samples by PaC were found to be positive by enzyme-immunoassays except for eight sera which were doubtful positives by the Enzymum test ToxoIgG from Boehringer. No negative sample by PaC was found positive by any of the enzyme-immunoassays. In PaC, when two latex preparations coated with different antigen were compared, the correlation was rather weak (r = 0.93) suggesting that the selection of the antigen can be critical. In conclusion, the four automated commercial immunoassays now available gave similar results. However, the discrepancies observed in this study underlined the importance of clinical and biological follow-up of the patients and the necessity to confirm the result. The introduction of a new technique such as PaC, which is now available for a large variety of assays in Clinical Chemistry and Microbiology, is justified by its intrinsic advantage of homogeneity. Therefore, automation is easy as well as the control of possible interference.

Long-term stability of vancomycin hydrochloride in intravenous infusions.

BACKGROUND AND OBJECTIVE: Vancomycin is often used in antibiotic infusions for hospitalized patients and it is advantageous to prepare such intravenous solutions in advance. The objective of this study was to investigate the long-term stability of this antibiotic stored at 4 degrees C in polyvinyl chloride (PVC) bags. METHOD: Five bags each of 0.5 or 1 g vancomycin hydrochloride per 100 ml of 5% dextrose were studied for 2 months by high-performance liquid chromatography, visual inspection and pH measurement. RESULTS: No colour change or precipitation was observed. The pH values of the preparations increased significantly over the period of study without influencing the antibiotic concentration. Based on a shelf-life of 90% residual potency, the vancomycin solutions were stable for at least 58 days at 4 degrees C. CONCLUSION: From a chemical stability viewpoint, the antibiotic may be prepared in advance by a centralized intravenous admixture service for use within the limits described.

Comparison of urinary excretion of albumin, alpha 1-microglobulin and retinol-binding protein in diabetic patients.

Small amounts of urinary proteins observed at early stages of diabetic nephropathy may result from both glomerular and proximal tubular dysfunction. However, the relative contribution of the two mechanisms remains controversial. We compared the urinary excretion of three low-molecular-weight proteins (albumin, alpha 1-microglobulin and retinal-binding protein) in 104 diabetic patients and 104 control subjects who had a plasma creatinine concentration of less than 130 mumol/l. Excretion of low-molecular-weight proteins was expressed as the ratio of protein to creatinine concentration. There were significant correlation (p < 0.01) between excretion of the three low-molecular-weight proteins measured in urine sample and 24-h urine collections in diabetic and control subjects. The concentrations of these proteins in single voided urinary samples and 24-h urine collections in diabetic patients were highly correlated. Excretion of retinal-binding protein, alpha 1-microglobulin and glucose in 24-h urine collections and of RBP and glucose in urinary samples was higher in diabetic than non-diabetic patients regardless of the type of diabetes and insulin-dependence. alpha 1-microglobulin and albumin excretions in urinary samples were significantly influenced by blood glucose control, as attested by the glycosylated haemoglobin level. Increased urinary excretion of alpha 1-microglobulin and retinol-binding protein reflected proximal tubular dysfunction in diabetic patients. However, only alpha 1-microglobulin correlated with the glycaemic control. It remains to be determined whether this protein could serve as an additional early marker of diabetic nephropathy.

Long-term stability of cefuroxime and cefazolin sodium in intravenous infusions.

Cefazolin and cefuroxime sodium are often used as antibiotic infusions for hospitalized patients. Because advance preparation of these intravenous solutions is efficient, the stability of both antibiotics stored at 4 degrees C in polyvinyl chloride (PVC) bags was studied. Five bags of solutions containing either 1 g of cefazolin sodium or 1.5 g of cefuroxime sodium per 100 ml of 5% dextrose were studied for 1 month by high-performance liquid chromatography (HPLC), visual inspection and pH measurement. No colour change or precipitation was observed. The pH values of both drugs increased significantly over the period of study. Based on a shelf-life of 90% residual potency, the cefuroxime sodium concentration was stable for 13 days when stored at 4 degrees C, and the cefazolin sodium concentration was stable for at least 30 days at 4 degrees C. Within these limits, both antibiotics may be prepared in advance by a centralized intravenous admixture service.

Inverse relationship between tobacco smoking and both psychotechnic and education levels.

The relationship between psychotechnic and education levels and smoking habits was evaluated in a population of 2,430 Belgian male army conscripts who were 18-29 y of age. Smoking habits were quantified by a questionnaire and by urinary cotinine-to-creatinine concentration ratio. The results were analyzed relative to education level (graded 1-4) and to results of psychotechnic tests (scored 1-9). The urinary cotinine-to-creatinine concentration ratio was correlated strongly with the number of cigarettes smoked/d (r = .76, p < .00005). The concentrations averaged 27 +/- 153 ng/mg (mean +/- standard deviation) creatinine in nonsmokers, 69 +/- 186 ng/mg creatinine in exsmokers, and 388 +/- 392 and 867 +/- 833 ng/mg creatinine in subjects who smoked fewer than or more than 10 cigarettes/d, respectively. Significant inverse relationships were observed between the urinary cotinine-to-creatinine concentration ratio and both education (p < .0001) and psychotechnic levels (p < .0001). The inverse relationship between smoking and both the education and psychotechnic levels underlined the importance of adapting smoking prevention programs to the intellectual capacities of the populations targeted.

Latex agglutination assay of human immunoglobulin M antitoxoplasma antibodies which uses enzymatically treated antigen-coated particles.

An assay of immunoglobulin M (IgM) antitoxoplasma antibodies which is rapid (less than 30 min), homogeneous, and reliable (interassay coefficient of variation, less than 11%) is proposed. Its principle is based on the observation that a suspension of latex particles coated with toxoplasma antigens, after treatment with proteinase K, becomes less agglutinable by IgG antibodies but more agglutinable by IgM antibodies. The difference between the activities of the two classes of antibodies is increased by the addition of a monoclonal antibody directed against the Fc region of IgM. Agglutination is measured with a special instrument which optically counts the particles that remain free after the reaction. Turbidimetric reading, although less sensitive, is also suitable. No significant interferences either by IgG antitoxoplasma antibodies or by rheumatoid factor or antinuclear antibodies were observed. The sensitivity was similar to that of the immunosorbent agglutination assay.

Assay of anti-HBs antibodies using a recombinant antigen and latex particle counting: comparison with five commercial tests.

An assay of anti-HBs antibodies based on agglutination of latex particles coated with recombinant HBs-antigen was compared with Abbott radioimmunoassay (Abbott-RIA), which uses a human plasma-derived antigen. The population examined consisted of 76 Abbott-RIA anti-HBs-negative prevaccinated subjects and 1044 serum samples anti-HBs found positive by Abbott-RIA, including 283 samples of subjects vaccinated either with a human plasma-derived vaccine (group A; n = 180) or with a recombinant vaccine (group B; n = 103). Correlation coefficients between the two techniques were respectively r = 0.89 for the whole population (n = 1044), r = 0.98 in group A and r = 0.74 in group B. Anti-HBs titres were higher with latex than with RIA in group B as shown by the regression slopes: latex = 508 + 1.11 RIA in group A and latex = -1138 + 3.97 RIA in group B, suggesting that some vaccinated subjects from group B produced antibodies against epitopes proper to the recombinant antigen. In the prevaccinated population and in group A, the latex results were compared with those of radioimmunoassays (Abbott, Sorin) and enzyme immunoassays (Behring, Roche, Pasteur). Only the Roche-EIA detected anti-HBs in the prevaccinated subjects. The correlation between the various immunoassays was r greater than 0.96 only for values higher than 100 IU/l.

Immunoassay of hepatitis B surface antigen by particle counting after pepsin digestion.

Particle counting immunoassay is based on latex agglutination, the reaction being measured by instrument counting of the particles remaining unagglutinated. Most interference which generally affects latex agglutination can be avoided by pepsin digestion of the sample, provided the antigen (Ag) of interest resists pepsin, which is the case of the hepatitis B surface antigen (HBsAg). Pepsin treatment has the additional advantage of inactivating antibodies and so releasing the Ag from immune complexes. We have set up an assay of HBsAg, proceeding in a prototype of Impact Instrument (Acade Diagnostic Systems, Belgium) at a rate of 60 samples.h-1 and a total running time of 2 or 4 h. This assay was compared with Abbott radioimmunoassay (RIA) in 706 consecutive patients (A) and 31 selected sera for which values close to the cut-off had been obtained by RIA (B). In A, 38 sera were found positive and 668 negative by both methods. In B, RIA after neutralization classified the samples as positive (n = 14), negative (n = 14), or dubious (n = 3). Complete agreement between latex and RIA was achieved for nine positive, 12 negative, and two dubious samples. Of five RIA-positive samples, two were classified as latex-negative and three as dubious in the latex assay. One sample dubious in RIA was found latex-positive and two RIA-negative samples were found, respectively, latex-positive and dubious; when retested after pepsin digestion, the first of them became RIA-positive.(ABSTRACT TRUNCATED AT 250 WORDS)