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Biomedical subjects

R L Boeckx

Publications and source records attributed to R L Boeckx.

At least 19 recordsLinked to original sources
PubMed1988

Chronic ethanol exposure in the embryonic chick heart: effect on myocardial function and structure.

To investigate the effect of chronic ethanol exposure on the embryonic chick heart, chick embryos were exposed daily to one of seven graded doses of ethanol or to saline only (shams) from 0 to 96 hr of incubation. One hour before and after exposure at 72 hr, and 1 hr before and after exposure at 96 hr, embryos were analyzed for changes in heart function, embryo tissue ethanol content, occurrence of anomalies, and embryo weights. At both 71 and 73 hr of incubation (during cardiogenesis), when compared to shams, heart rate (HR) in embryos receiving ethanol doses greater than 0.0375 ml increased significantly (P less than .05) with commensurate increases in injected ethanol. Additionally, at 73 hr, depressed cardiac contractility, measured as shortening fraction, was noted at doses greater than or equal to .0375 when compared to shams. While slight increases in shortening fraction (SF) across dose were noted at 95 and 97 hr, only random doses were statistically significant from shams, with no specific trend in either HR or SF at this postcardiogenesis stage. Within each time group, gas chromatography analysis of embryo tissue ethanol content demonstrated a linear relationship between dose injected and tissue ethanol content retrieved. With increasing dose and stage, viability decreased. Weights of ethanol-injected embryos were not significantly different from shams within each time group. Our studies of the response of the embryonic chick heart to ethanol indicate both dose and stage susceptibility, with greater susceptibility to ethanol injury during active cardiogenesis.

Animals↗
PubMed1988

Determination of theophylline concentrations by AccuLevel.

Determination of theophylline concentrations in 29 paired venous samples by AccuLevel and EMIT disclosed excellent correlation. Evaluation of precision of AccuLevel by 20 replicate analyses disclosed a coefficient of variation of 3.5%. AccuLevel is an accurate, precise, rapid method of determination of theophylline concentrations in whole blood.

Blood Chemical Analysis↗
PubMed1988

Impact of AccuLevel on treatment of acute asthma.

Study of the impact of rapid availability of theophylline concentrations on emergency treatment of acute asthma disclosed use of AccuLevel in 50 children significantly shortened the time required to reach concentrations of at least 10 micrograms/mL and shortened time spent in the emergency room as compared with 50 children in whom serum concentrations were measured only by EMIT.

Acute Disease↗
PubMed1986

Evaluation of determination of theophylline concentrations by Seralyzer.

Determination of theophylline concentrations by Seralyzer in 28 paired serum and plasma samples disclosed almost identical results. Comparison of determinations by Seralyzer and enzyme-multiplied immunoassay in 31 paired serum samples disclosed significant underestimation by Seralyzer when recalibrated whenever results of analysis of a 15-micrograms/mL control exceeded limits of +/- 3 micrograms/mL. Determinations by Seralyzer did not differ significantly from enzyme-multiplied immunoassay with narrower limits of 15 +/- 2 micrograms/mL for Seralyzer calibration for 18 paired samples. Seralyzer results are sufficiently reliable for clinical use if the instrument is recalibrated whenever analysis of the 15-micrograms/mL control falls outside limits of +/- 2 micrograms/mL.

Child↗
PubMed1985

Evaluation of the Du Pont Theophylline Assay adapted to a centrifugal analyzer.

We evaluated the Du Pont Theophylline Assay, a particle-enhanced turbidimetric inhibition immunoassay (PETINIA) for the measurement of theophylline in human serum. The procedure was applied to the Cobas-Bio centrifugal analyzer, and was compared to an enzyme immunoassay (EMIT) method and a high performance liquid chromatographic (HPLC) procedure. Day-to-day precision was 3.7% (1 SD coefficient of variation) at 7.1 mg/L, 3.3% at 17.7 mg/L, and 3.9% at 27.8 mg/L. The assay was linear up to 40 mg/L, and the correlation between the PETINIA, EMIT, and HPLC methods was good [PETINIA/EMIT: y = 0.94x + 0.63, r = 0.98, Syx = 1.13; PETINIA/HPLC: y = 1.00x - 0.89, r = 0.99, Syx = 0.66, where Syx is the standard deviation of the residual error of regression], when evaluated using specimens from 135 patients receiving theophylline. No interference from hemolysis, lipemia, icterus, or other methylxanthines was observed. Of the major metabolites of theophylline, only 1,3-dimethyluric acid showed any significant cross-reactivity (2.1 mg/L apparent theophylline at 20 mg/L 1,3-dimethyluric acid). The method is reliable and cost-effective for the measurement of theophylline in serum.

Centrifugation↗
PubMed1984

Chemiluminescence: applications for the clinical laboratory.

The chemical features and applications of chemiluminescence are reviewed, with special attention to bacterial and firefly bioluminescence and to uses of chemiluminescence in direct substrate assays, enzyme assays, solid-phase reactions, and immunoassays.

Adenosine Triphosphate↗
PubMed1982

Methylmalonic acidemia with the unusual complication of severe hyperglycemia.

We describe a case of neonatal methylmalonic acidemia with the unusual complication of severe, insulin-resistant hyperglycemia. Methylmalonic acidemia, an inherited metabolic disease affecting the catabolism of propionic acid, is manifested by persistent metabolic acidosis, urinary excretion of large amounts of methylmalonic acid, and occasionally by hypoglycemia. Severe and persistent metabolic acidosis and hyperglycemia, despite large doses of insulin, were observed in this infant, who excreted large amounts of methylmalonic acid. The diagnosis of methylmalonic acidemia was confirmed by gas chromatography-mass spectroscopy, but the patient died before the defect in glucose tolerance could be delineated. We hypothesize that, in addition to the methylmalonic acidemia, the patient may have had an insulin-receptor defect, which was manifested as an inappropriate response to endogenous and exogenous insulin.

Acidosis↗
PubMed1981

Adolescent pregnancy testing: which test to use.

In order to study the sensitivity and efficiency of five pregnancy tests, we evaluated four types of urine tests in 162 adolescent girls in whom pregnancy was suspected; a serum test was performed in 46 of them. We found that (1) an increase in sensitivity occurred at the expense of specificity, (2) the quantitation of the beta-subunit of human chorionic gonadotropin in serum proved to be the most reliable test for pregnancy, and (3) the latex agglutination inhibition tube test (Placentex) was the most accurate of the four types of urine tests evaluated. We concluded that for adolescents, the serum pregnancy test is the preferred test, but when it is not available, the urine latex agglutination inhibition tube test offers the most reliable alternative.

Adolescent↗
PubMed1981

A prospective study of infant zinc nutrition during intensive care.

Zinc nutritional status was evaluated during intensive care for 55 infants. Plasma zinc, serum albumin, alkaline phosphatase, growth, nutrient intake, and clinical data were examined. The more premature infants (less than 32 wk gestational age) had higher zinc levels on admission, but their levels declined more rapidly than in more mature infants. Zinc level did not correlate with albumin or alkaline phosphatase. Low zinc levels (45 microgram/dl or less) occurred at about 6 wk in 14 of 39 premature infants. True zinc deficiency occurred in two premature infants; it was manifest by increased gastric residuals, poor suck, and decreased growth, but neither infant had the skin or gastrointestinal signs generally expected with zinc deficiency. There was evidence that sick premature infants may need more zinc than is currently recommended to supplement parenteral nutrition and more than the amount supplied in premature infant formulas currently available.

Critical Care↗
PubMed1981

Adaptation of the EMIT gentamicin and tobramycin procedure to the IL microcentrifugal analyzer.

We have adapted the Syva Emit gentamicin and tobramycin procedure to the IL microcentrifugal analyzer, MCA III. With this instrument the recommended instructions for reagent preparation and reaction sequence did not produce a useable standard curve. We modified the dilutions and volumes for the working reagents and reversed the sequence of addition of the working reagents. WE assessed the linearity and precision of the analysis and compared the Syva gentamicin and tobramycin Emit procedure on the IL MCA III with the semiautomated procedure on a Gilford Stasar III spectrophotometer. With the IL MCA III only 3 to 5 microliter of serum is used, 17 analyses can be obtained in 8 min, and the reagent costs are reduced considerably.

Anti-Bacterial Agents↗
PubMed1981

A bioluminescence micromethod for measuring chloramphenicol in serum.

Bioluminescence provides a sensitive analytical approach for the measurement of low concentrations of ATP and can be used to monitor any reaction in which ATP is consumed or synthesized. We describe a quick, sensitive method involving bioluminescence for the quantitation of chloramphenicol in serum. Chloramphenicol acetyl transferase catalyzes the acetylation of chloramphenicol in the presence of acetyl coenzyme A. ATP is consumed when the acetylation reaction is coupled to the acetyl coenzyme A synthetase reaction. Residual ATP is then assayed with the firefly luciferin-luciferase reaction. The procedure can be completed in less than 1 h and requires as little as 20 microliter of serum. The response of the assay is linear with concentration through a range of 2 to 20 mg/L and shows good correlation with a gas-chromatographic method (r = 0.978) and a radioenzymic method (r = 0.985). No significant interference was found from five other antibiotics tested. The small sample requirement makes the assay especially applicable to infant and pediatric monitoring, where the effects of toxicity are greatest.

Chloramphenicol↗