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Biomedical subjects

M G Bissell

Publications and source records attributed to M G Bissell.

At least 19 recordsLinked to original sources
PubMed2000

The possible association of decreased total cholesterol and severity of disease in elderly hospitalized patients.

The object of our study was to determine if any association exists between low serum cholesterol (< 4.14 mmol/l) and adverse outcomes in elderly patients > 60 years. Patients with low serum cholesterol were compared to a patient population with high serum cholesterol (> 6.22 mmol/l) and normal cholesterol (> or = 4.14 to < or = 6.22 mmol/l). Only hospitalized patients > 60 years, who were not on cholesterol lowering drugs, and did not have cardiovascular or liver disease were included in this study. The study group was 157 patients (79 with low, 78 with high, and 23 with normal cholesterol concentrations). Using the Kruskal-Wallis tests, the low cholesterol group was found to have statistically (p < 0.05) longer length of stay (average difference of > 11.1 days), higher hospital re-admission rate over a 1-year period (average difference of > 0.4 re-admissions), greater use of acute care services (average difference of > 0.6 days), and more emergency room (ER) visits over 1 year (average difference of > 0.5 admissions).

Age Factors↗
PubMed1999

Development of a urinary free cortisol assay using solid-phase extraction-capillary electrophoresis.

In clinical practice, the measurement of urinary free cortisol (UFC) provides the most sensitive and specific diagnostic information for excess adrenal production of cortisol. The existing methodologies (RIA and HPLC) are time consuming, costly, involve tedious extractions, derivatizations and problems with non-specific interactions with cortisol metabolites in urine. In the present study, we describe the development of an SPE-CE method for the rapid analysis of UFC. UFC was concentrated using SPE C18 cartridges (3M Empore) under a vacuum and eluted with acetonitrile-SDS. The use of 10% acetone to wash cartridges before final elution with acetonitrile-SDS showed significant improvements in the free cortisol recovery. The complete extraction was accomplished in 10-15 min with a recovery of 89-94%. CE analysis was done on a Beckman P/ACE 5010 with detection at 254 nm using a neutral capillary. Detection limits of free cortisol in urine was improved to 10 microg/l with SPE compared to 500 microg/l without SPE. No interferences either from BSA or other urinary cortisol metabolites affected the free cortisol determinations. The results showed the feasibility of a rapid UFC detection with improved sample handling capacity.

Electrophoresis, Capillary↗
PubMed1999

The effect of benchmarking clinical practice with the clinical laboratory. An institutional case study.

The improvement of quality in clinical care can greatly benefit form continuous benchmarking with information based on laboratory data. To be most effective, the information is best provided in the form of real-time disease management decision support. Such an approach requires advances in the implementation of hospital information systems. This article describes ground-breaking work at LDS Hospital in Salt Lake City, Utah that provides examples of major well-documented impacts of the "intelligent laboratory report" on patient outcomes.

Anti-Bacterial Agents↗
PubMed1998

The laboratory's role in outcome assessment.

How does the laboratorian influence patient outcome, and how is this influence measured? The clinical laboratory gives vital support to decisions about diagnosis, treatment, and management. Outcome assessment must include a structured approach to performance improvement, proper test utilization, and defining best practices.

Benchmarking↗
PubMed1996

Laser induced resonance energy transfer--a novel approach towards achieving high sensitivity in capillary electrophoresis. I. Clinical diagnostic application.

Most of the procedures currently performed by capillary zone electrophoresis (CZE) with laser induced fluorescence detection requires prior derivatization. This increases cost, the turn-around-time and chances of extraneous contaminations. CZE with laser induced resonance energy transfer is demonstrated as a viable alternative for detecting non-fluorescent compounds with no prior derivatization. The feasibility of this approach is demonstrated by separating and directly detecting salicylic acid (2,4-dihydroxybenzoic acid), gentisic acid (o-methoxybenzoic acid), salicyluric acid (o-hydroxyhippuric acid) and 4-aminosalicylic acid in urine. The detection of salicylate in serum is also shown. The method is highly sensitive with detection limits in the 1.10(-7) M range. Importantly it requires no prior preconcentration or sample preparation and can be used with complex sample matrices such as serum and urine.

Aminosalicylic Acid↗
PubMed1995

Micellar electrokinetic capillary chromatographic separation of steroids in urine by trioctylphosphine oxide and cationic surfactant.

Separation of the six structurally similar and hydrophobic neutral steroids, testosterone, dimethyltestosterone, testosterone propionate, cortisone, hydrocortisone and 17-deoxycorticosterone, was achieved by hydrophobic micellar electrokinetic chromatography. A triphasic separation involving micellar dodecyltrimethylammonium bromide (DTAB), a dynamic bilayer formed due to electrostatic interaction between the silica surface and DTAB, and aqueous phase is proposed to account for the observed separation of the steroids. The running buffer consisted of 0.05 M DTAB and 0.0052 M trioctylphosphine oxide in 0.01 M of phosphate buffer pH 7.4. A detection limit of 500 ng/ml was achieved for each steroid and the application of the method to urine samples is described.

Chromatography↗
PubMed1993

Measurement of vitamin C by capillary electrophoresis in biological fluids and fruit beverages using a stereoisomer as an internal standard.

Ascorbic acid (or vitamin C) is an important component of many biological systems and various physiological roles have been described for it. A rapid and simple capillary electrophoresis method for ascorbic acid measurements in biological fluids as well as in beverages was developed. A stereoisomer of ascorbic acid, isoascorbic acid, not normally found in nature, was used as the internal standard for this assay. The analysis was performed in a 30 cm x 75 microns I.D. fused-silica capillary with 100 mM tricine buffer, pH 8.8, and measured by UV absorbance at 254 nm. The method was sensitive to 1.6 micrograms/ml and linear to 480.1 micrograms/ml. Within-run R.S.D. was 3.2% (93.5 +/- 3.0 micrograms/ml, mean +/- S.D., n = 18) and run-to-run R.S.D. was 3.3% (35.6 +/- 1.2 micrograms/ml, mean +/- S.D., n = 10) and 1.9% (149.4 +/- 2.8 micrograms/ml, mean +/- S.D., n = 10). Average spiked recovery from human plasma samples was 98.0%. The technique has been demonstrated to be suitable for assay of vitamin C in biological samples and some fruit juices.

Ascorbic Acid↗
PubMed1991

Accuracy of portable blood glucose monitoring. Effect of glucose level and prandial state.

Glucose was determined on capillary and venous blood samples from 274 adult diabetics by three different methodologies: the Glucoscan 2000 and Accu-Check II portable glucose meters (capillary) and the Kodak Ektachem 700 analyzer (venous). Both glucose meters correlated significantly with the Ektachem results. A significant positive bias was found for the Glucoscan compared with Ektachem, not found with the Accu-Check II. The Accu-Check performed better than the Glucoscan at venous plasma glucose levels less than 1 g/L. The mean error of Glucoscan determinations was significantly greater and biased positive when the measurement was performed within 4 hours of eating, whereas no such effect was seen with Accu-Check error. Multiple regression analysis revealed that the Glucoscan measurement was independently influenced by both venous plasma glucose and prandial state, whereas the Accu-Check II measurement was not dependent on either variable. The within-run precision for both glucose meters were comparable.

Adult↗
PubMed1988

Renal effects of dopamine in vascular surgical patients.

Low-dose dopamine (DA) is often used in surgical patients to induce diuresis when appropriate volume replacement is unsuccessful. Despite wide application, there are little objective data supporting any beneficial effects on renal hemodynamics in this patient population. To better define the response to dopamine in the clinical setting, we studied the renal effects of low-dose DA in 13 patients having vascular surgery. Glomerular filtration rate (GFR) and renal blood flow (RBF) were measured by inulin and p-aminohippurate clearance, respectively. Group I (n = 8) included patients in stable condition after operation who were administered intravenous DA, 0.5 micrograms/kg/min, for 2 hours. RBF significantly increased from 579 +/- 85 to 726 +/- 114 ml/min/1.73 m2 (p less than 0.05). Increases were also observed in GFR (95.0 +/- 10.9 to 107 +/- 15.7 ml/min/1.73 m2), sodium excretion (164 +/- 35 to 239 +/- 53 mu Eq/min), and osmolar excretion (709 +/- 78 to 866 +/- 93 mu Osm/min). There were no changes in urine output (2.17 +/- 0.36 to 2.49 +/- 0.43 ml/min). Group II (n = 5) consisted of patients having abdominal aortic surgery who were treated with DA, 2.0 micrograms/kg/min, before and after surgery. Increases in RBF were seen in both the preoperative period (414 +/- 59 to 659 +/- 96 ml/min/1.73 m2, p less than 0.01) and postoperative period (439 +/- 60 to 623 +/- 94 ml/min/1.73 m2, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Diuresis↗
PubMed1988

Chemical assay of p-aminohippuric acid simplified by use of dimethylaminocinnamaldehyde in ethanol.

We have developed a new and simple method of p-aminohippuric acid determination by use of dimethylaminocinnamaldehyde (DACA). It differs from previous methods using DACA in that the reaction is carried out in ethanol rather than in dilute acid. This results in deeper and more stable color development. We have used this method successfully to determine effective renal plasma flow in a clinical study of this variable in pregnant women.

Aminohippuric Acids↗
PubMed1988

Time series modeling for quality control in clinical chemistry.

Autocorrelation of clinical chemistry quality-control (Q/C) measurements causes one of the basic assumptions underlying the use of Levey-Jennings control charts to be violated and performance to be degraded. This is the requirement that the observations be statistically independent. We present a proposal for a new approach to statistical quality control that removes this difficulty. We propose to replace the current single control chart of raw Q/C data with two charts: (a) a common cause chart, representing a Box-Jenkins ARIMA time-series model of any underlying persisting nonrandomness in the process, and (b) a special cause chart of the residuals from the above model, which, being free of such persisting nonrandomness, fulfills the criteria for use of the standard Levey-Jennings plotting format and standard control rules. We provide a comparison of the performance of our proposed approach with that of current practice.

Chemistry, Clinical↗