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F Desjarlais

Publications and source records attributed to F Desjarlais.

13 recordsLinked to original sources
PubMed1989

Clinical usefulness of estimation of serum fructosamine concentration as screening test for gestational diabetes.

Serum fructosamine levels and fructosamine/protein ratios were measured in 100 pregnant women who underwent glucose tolerance tests because of clinical risk. Compared with normal pregnant women, the 13 study participants with gestational diabetes had higher fructosamine/protein levels (39 +/- 3.9 mumol/gm versus 37 +/- 3.2 mumol/gm, p less than 0.05), fasting serum glucose levels (107 +/- 13.7 mg/dl versus 82 +/- 8.6 mg/dl, p less than 0.001), and area under curve of glucose tolerance test (36 +/- 5 gm x min x dl-1 versus 22 +/- 3.6 gm x min x dl-1, p less than 0.001). The serum fructosamine levels were not significantly different between the two groups of participants (2.3 +/- 0.26 mmol/L versus 2.2 +/- 0.17 mmol/L); 10 of the 13 women with diabetes had a fructosamine/protein ratio within 2 SD of the mean of the groups of normal pregnant women. Spontaneous caloric intakes (r = 0.72, p less than 0.005) and the hospital mean daily capillary glucose levels during diabetic diet (r = 0.72, p less than 0.005) correlated better with the fructosamine/protein ratio than with fasting serum glucose levels (r = 0.58, p less than 0.05) and area under curve (r = 0.57, p less than 0.05). Consequently, serum fructosamine and fructosamine/protein ratio levels should be considered insensitive as a screening test in pregnant patients with clinical risk of gestational diabetes.

Adult↗
PubMed1989

Technical and clinical evaluation of fructosamine determination in serum.

We evaluated a serum fructosamine (glycated serum proteins) assay for efficacy in the diagnosis and follow-up of diabetic patients. A Roche reagent kit, based on nitroblue tetrazolium reduction in alkaline medium, was used in COBAS FARA centrifugal analyzer. We demonstrated that this method is precise, linear and unaffected by serum hemolysis. However, bilirubin affected the test positively and lipemia negatively. Fructosamine (F) correlated positively with total protein (P) (r = 0.809) and albumin (r = 0.746) in a group of 48 non-diabetic individuals. A good correlation was observed between F and glycated hemoglobin from the sera of 514 patients (r = 0.794). A better correlation (r = 0.838) was obtained when F was corrected for P concentration (F/P). Different F and F/P means were calculated only in patients with overt diabetes, compared to normals. Gestational diabetes was associated with a highly significant F increase. However, its low sensitivity (21%) precludes the use of F as an effective screening test for that condition. Nevertheless, because of its simplicity, low cost and rapidity in reflecting changes in the metabolic control of diabetes, F should be considered a valuable test to assess glycemic control in diabetic patients.

Adult↗
PubMed1985

A simple procedure for the preparation of concentrated sera.

We shall describe a simple technique to prepare concentrated sera that will have a near normal osmolality. A pool of sera is first frozen for 72 h at -20 degrees C and then allowed to thaw at 6 degrees C for 16 h. Care is taken to avoid any shaking of the bottle. The surface serum is then cautiously aspirated with a pipette. The left-over serum is mixed and filtered. To decrease the osmolality of this concentrated serum, we treated it with 200 mg of resin (Rexyn AG 501, H-OH) per 5 mL serum and then filtered it to eliminate the resin. We studied the effects of the height of the liquid column, the freezing temperature, the volume of serum decanted, the resin concentration and the duration of the extraction step. We also evaluated the stability of this concentrated serum at 6 degrees C, -20 degrees C and -70 degrees C. We also verified whether readjustment of the pH of the concentrated resin-treated serum would have improved its stability at -20 degrees C.

Blood Chemical Analysis↗
PubMed1985

Analytical interference of drugs in clinical chemistry: I--Study of twenty drugs on seven different instruments.

We have investigated the effect of 20 drugs on the accuracy of results obtained from seven instruments now widely used in clinical biochemistry laboratories: Abbott VP, aca II, Cobas Bio, Ektachem 400, Hitachi 705, KDA and SMAC. Eleven to 18 constituents were analysed on each instrument. Our results lead us to the following conclusions: (1) only rarely does drug interference with a method lead to a clinically significant change in a measured value; (2) the magnitude of the change may relate linearly or non-linearly to the drug concentration but is usually independent of the target analyte concentration; (3) interference with a chemical reaction on one instrument does not always mean that the same reaction will be altered in the same way on other instruments; (4) no interferences were found for drugs with therapeutic levels in the low micro-molar range; (5) in most cases the interference could not be predicted from the chemical nature of drug.

Autoanalysis↗
PubMed1985

Analytical interference of drugs in clinical chemistry: II--The interference of three cephalosporins with the determination of serum creatinine concentration by the Jaffé reaction.

It is well known that some cephalosporins interfere with the Jaffé reaction for creatinine measurement. This interference varies according to the thirteen instruments and eighteen methodologies studied. Our study has shown that: the proportion of picric acid, NaOH and serum have only a slight effect on the interference; the addition of a buffer to the NaOH solution increases the interference due to cephalothin and cephaloridine, but lessens that due to cefoxitin; dialysis decreases the interference; in kinetic methods, the choice of times at which readings are made influences the magnitude of the interference; a higher incubation temperature increases the effect of cefoxitin and decreases the effects of cephalothin and cephaloridine; pre-incubation with NaOH decreases the interference due to cefoxitin, but has no significant effect on the interference due to cephalothin or to cephaloridine.

Autoanalysis↗
PubMed1982

Study of seasonal variations for eighteen biochemical parameters over a four-year period.

The seasonal variations of eighteen parameters of a biochemical profile were studied under standardized conditions. More than 2,600 blood samples from a homogeneous group of women aged 30 to 39 years were processed on a well controlled instrument over a four-year period. Monthly means were first calculated and then seasonal means for two delimitations of seasons and for different combinations of years. Even though many statistically significant differences were found between seasons, only in the case of two parameters, uric acid and triglycerides, was the percentage of difference between the highest and the lowest seasonal means greater than the inter-assay CV of the methods. For these two parameters the results of other age groups of women and men were also computed. Uric acid was higher in summer compared to fall by 5% in the case of women aged 30-39 and by 7% in the case of men aged 30-39, the method inter-assay CV being 4.5%. Triglycerides were 6% higher during spring compared to fall for women aged 30-39, but surprisingly, 22% higher in winter compared to fall in the case of men aged 30-39. For younger groups of men the difference is much smaller and for men aged 20 to 25 years the difference is not significant. In general, we have been unable to confirm the variations previously reported by many authors.

Adult↗
PubMed1981

Limitations of conventional laser nephelometry for the measurement of beta 2-microglobulin, lysozyme, alpha 1 fetoprotein and myoglobin in serum and urine.

We have tested some assay procedures for the measurement of beta 2-microglobulin, lysozyme, alpha 1-fetoprotein and myoglobin in serum and/or urine with the use of a manual Behring laser nephelometer. The assay working ranges were: beta 2-microglobulin: 0.0038-0.038 g/L; lysozyme: 0.005-0.325 g/L. We have studied the effect of different antiserum dilution ratios and of different concentrations of polyethylene glycol 6000 on the calibration curves. The best standard curves were obtained with the use of the following antiserum dilutions: anti-beta 2-microglobulin: 1:3 with saline, 40 g/L PEG; anti-lysozyme: 1:5 with saline, 40 g/L PEG; anti alpha 1-fetoprotein: concentrated; anti-myoglobin: concentrated with added 40 g/L PEG. In the case of beta 2-microglobulin and lysozyme, laser nephelometry, could be a fast and simple procedure if a 10 times increase in sensitivity can be achieved. For the measurement of alpha 1-fetoprotein and myoglobin, the sensitivity of laser nephelometry was disappointing when compared to those reported for radioimmunoassay and enzyme immunoassay.

Beta-Globulins↗
PubMed1981

Basic characteristics and evaluation of a partially automated Behring laser nephelometer for the measurement of IgG, IgA, IgM and C3c in serum.

We have evaluated a partially automated Behring laser nephelometer for the measurement of IgG, IgA, IgM and C3c in serum. The system consisted of a manual Behring laser nephelometer, an automatic cuvette carrier and a Hewlett-Packard 9815 A calculator/printer. The system could process 240 preincubated samples per h when the interval between each voltage reading was set at 15 s. Day-to-day precision was near 6%. We obtained the worst precision for the determination of IgG which requires the smallest volume of diluted sample (10 microliters). The Frigen treatment used to clarify turbid sera seems to decrease IgG and increase C3c concentrations. The addition of polyethylene glycol 6000 at a concentrations of 40 micro/L in the reaction mixture did not improve the assay ranges. Comparison studies with radial immunodiffusion for the four proteins and with the IgM - BMC Immunological Turbidity Test using either least-squares or Deming's regressions gave very good correlation figures, except for C3c and for some IgM paraproteins. We could decrease the cost per test by re-using the plastic cuvettes. The utilization of the calculator-printer greatly simplified data handling but the automatic carrier was not considered a real asset without complete automation.

Autoanalysis↗
PubMed1980

In search of optimum conditions for the measurement of creatine kinase activity: a critical review of nineteen formulations.

We compare the reagent composition recommended by six different groups including three European societies for the determination of creatine kinase activity in serum using the coupled hexokinase/glucose-6-phosphate dehydrogenase (EC 2.7.1.1/1.1.1.49) reactions. Even though discrepancies exist between these methods, there are, nevertheless, major areas of consensus which permit a reasonable extrapolation of an approximate composition for optimum response. We then ascertain how reagents used in thirteen commercial kits differ from these approximated optimum conditions. Except for four companies, all the reagent compositions differ remarkably from the conditions recommended by the six groups.

Adenosine Diphosphate↗
PubMed1979

Pitfalls to avoid when comparing CK-MB fractionation by antibody inhibition reaction and DEAE-Sephadex column chromatography.

1. We compare the Roche ion-exchange column chromatography and the Merck antibody inhibition reaction for CK-MB fractionation in 51 sera. Measurements of total CK and CK-MB activities must be done under the same conditions for each method in order to correlate the results. 2. A decisional value must be used for the interpretation of CK-MB results. We have used 10% for the inhibition assay and 3% for the chromatography procedure. The use of a percentage should be preferred to use of CK-MB activity alone. 3. When the % of CK-MB was established for the 51 patients only 4 results disagreed between the two methods. Three of these could be explained by a lack of sensitivity of the column chromatography procedure. 4. The antibody assay produces reliable results. Since CK-BB and CK-MB are simultaneously measured, the method is therefore prone to interference by CK-BB when present in serum. The assay is greatly affected by the presence of adenylate kinase in serum. It is not necessary to run a serum blank with this procedure when the serum in pre-incubated for 7 minutes with the reagents. 5. The Roche method also produces reliable results but offers less sensitivity when total CK remains in the normal range. The procedure is much less affected by the presence of adenylate kinase.

Chromatography, Ion Exchange↗