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Biomedical subjects

J E Logan

Publications and source records attributed to J E Logan.

At least 19 recordsLinked to original sources
PubMed1994

Food-containing hypocaloric diets are as effective as liquid-supplement diets for obese individuals with NIDDM.

OBJECTIVE: This study was designed to determine if food-containing hypocaloric diets are as effective as liquid-supplement diets in promoting weight loss for obese individuals with non-insulin-dependent diabetes mellitus (NIDDM). RESEARCH DESIGN AND METHODS: Forty NIDDM subjects with body mass indexes (BMIs) of 30-40 kg/m2 were randomized to one of two 800-kcal diets for 12 weeks. Group A received liquid supplement only, and group B received supplement plus an evening meal. Both groups received an intensive behavioral education program. RESULTS: Weight loss and improvements in glycemic, blood lipid, and blood pressure parameters were similar for the two groups. Weight loss averaged 15.7 kg for the entire group. The need for insulin, anti-diabetes, and anti-hypertensive medication decreased significantly. No serious side effects were observed. CONCLUSIONS: Both food-containing and supplement diets providing 800 kcal a day effectively promote weight loss for obese individuals with NIDDM.

Body Mass Index↗
PubMed1984

International Federation of Clinical Chemistry (IFCC). Scientific Committee, Analytical Section. IFCC/WHO principles and recommendations on evaluation of diagnostic reagent sets used in health laboratories with limited resources. Part 3. Selection and evaluation using reference materials. General considerations.

The purpose of this document is to provide general considerations for the selection and evaluation of clinical chemistry kits in laboratories with limited resources. Separate documents have been developed to provide guidance on experimental procedure, the statistical treatment and interpretation of the data and criteria for acceptable performance of diagnostic kits designed to measure specific analytes.

Drug Labeling↗
PubMed1982

Serum calcium methodology--a Canadian assessment based on the application of the reference method.

The reference method for serum calcium [J.P. Cali, G.N. Bowers Jr., D.S. Young (7)] has provided target values in six voluntary interlaboratory studies each using five or six human serum samples, mostly in liquid form. Eighteen method/instrument categories, used by at least five laboratories in the last two studies, have been rated in four classes for inter- and intra-laboratory accuracy and for precision. There has been a noticeable improvement in the performance of some individual laboratories but no real improvement in the overall results. Certain poor performance procedures were used less often in the most recent studies; however, some continue to be used. There has been a great increase in automated procedures but the results were not consistently reliable. There was wide diversity in the sources of supply of standards and quality control materials and their use in the laboratories. The wide variety of laboratory reference ranges (normal ranges) for the adult male was not consistent with the analytical results and differences in clinical interpretation occurred. On a daily workload basis the best procedures account for approximately 80% of the analytical tests performed per day whereas the worst procedures account for only 3% of the tests per day.

Calcium↗
PubMed1980

Production of low glucose serum for quality control and evaluation of yeast treatment, lyophilization and storage conditions on serum constituents.

In order to provide quality control serum in the hypoglycemic range, pooled human serum was treated with yeast. Yeast destroyed about 50% of the serum glucose in about 4 1/2 hrs. The yeast-treated serum remained suitable for quality control of the most commonly analyzed clinical chemistry constituents which showed only very little change in most cases. Serum triglycerides were increased by about 40% and bilirubin decreased by about 20% during the treatment. Lyophilization of serum samples (yeast-treated or not) resulted in significant decreases of some enzymes activities. Exposure at 22 degrees C of samples lyophilized (7 days) and non-lyophilized (4 days) resulted in practically no change except for certain enzymes. No significant differences were observed in the clinical chemistry measurements including glucose one month and three months after preparation of samples lyophilized (stored in a refrigerator) and non-lyophilized (store in a freezer).

Bilirubin↗
PubMed1978

A scheme for the evaluation of methods in clinical chemistry with particular application to those measuring enzyme activities. Part I: general considerations.

A 20-point system is presented whereby commercially produced clinical chemistry procedures, i.e., in vitro diagnostic kits, may be assessed for adequacy of packaging, labelling and enclosed literature. Criteria are given for the selection of a reference method to use in the test method evaluation and the design of a patient comparison study using these two methods is described. The importance of standards and calibration materials as they relate to accuracy and specificity is discussed. A procedure for assessing accuracy by recovery studies is outlined. A method for the assessment of precision on a within-day and a day-to-day basis is described.

Canada↗
PubMed1978

A scheme for the evaluation of methods in clinical chemistry with particular application to those measuring enzyme activities. Part II: analysis of data and performance assessment.

Recommendations are made concerning the editing of day-to-day reproducibility data for establishment of precision in the evaluation of a clinical chemistry method. The concept of diagnostic and equalized diagnostic indices is introduced together with formulae for their generation from the usual precision and accuracy data acquired in method evaluations. These indices allow direct comparison of data obtained from procedures for measuring enzyme activities which employ a variety of experimental conditions and units in their protocols. The equalized diagnostic index permits assessment of the suitability of the normal range assignment. Permissible limits of variation (PLV) and permissible limits of discrepancy (PLD) have been developed empirically from detailed examination of data from method evaluations and proficiency testing surveys in the published literature. The application of the diagnostic indices and the two permissible limits of criteria have been illustrated using data from the assessment of 19 kits measuring CPK activity. The inconsistency of the correlation coefficient in method comparisons is confirmed.

Canada↗
PubMed1978

An investigation of factors influencing the measurement of creatine phosphokinase activity in serum using coupled enzymatic methods.

1. The factors influencing the measurement of creatine phosphokinase (CPK) activity in serum by coupled enzymatic methods were investigated to establish optimum conditions for this type of assay. Such a study was indicated following observations by the authors of poor performance of commerically produced reagent kits together with the failure of most of the established an well accepted methods to operate under true optimum zero order kinetics in the reaction phase state. 2. The factors invested were the effects of pH, substrate concentrations (creatine phosphate, glucose and NADP+), added auxiliary (hexokinase) and indicator (glucose-6-phosphate dehydrogenase) enzymes, dithiothreitol (DTT) as an activator and conditions of storage of substrate stability. DTT was found to be a suitable activator but not a reactivator of the reaction. The optimum concentrations of creatine phosphate, glucose and NADP+ were found to be 20.0, 20.0 and 2.0 mmol/litre, respectively. Optimum activieies of the enzymes, glucose-6-phosphate dehydrosenase and hexokinase were 1000 and 2000 units/litre, respectively. 3. The between-day precision of the method for measuring serum at pH 6.8 and 30 degrees C at three activity levels under the optimum conditions developed was excellent yielding coefficients of variation ranging from 2.0 to 2.7%.

Creatine Kinase↗
PubMed1977

The use of in vitro diagnostic kits in hospital laboratories in Canada.

1. A survey conducted among hospital laboratories has yielded data from 640 institutions concerning the use of diagnostic kits and reagents in Canada. 2. Kits designed to test for chemical constituents were most frequently used in hospitals of 51 to 600 bed capacity whereas the ones for enzymes were most extensively used in 201 to 700 bed-size institutions. Kits based on the CPB principles were generally used in hospitals of more than 200 beds whereas those based on RIA were only in frequent use where the bed capacity was 351 or more. 3. The following tests were most often performed by kits: aminotransferases, amylase, urea, LDH, phosphatases, glucose, CPK, bilirubin, calcium, uric acid, T-4, T-3, digoxin and vitamin B12. 4. The survey reflects a continuing and increasing usage of in vitro diagnostic kits and associated blood analyzer systems. It also indicates a significant adoption of assay kits which utilize RIA and CPB principles.

Blood Chemical Analysis↗
PubMed1977

An evaluation of commercial kits for creatine phosphokinase assay.

1. The evaluation of seven colorimetric and twelve kinetic or ultra-violet (UV) creatine phosphokinase (CPK) kit methods for their reliability as a diagnostic tool in clinical laboratories has revealed that over 35% of such commercial products readily available in Canada do not yield reliable results. 2. Six out of seven colorimetric kits failed to meet the criteria of minimum reliability as did one of the twelve UV kinetic kits.

Creatine Kinase↗