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D E Goldstein

Publications and source records attributed to D E Goldstein.

At least 37 records · Page 2Linked to original sources
PubMed1992

Affinity binding assay of glycohemoglobin by two-dimensional centrifugation referenced to hemoglobin A1c.

We describe an automated assay of glycohemoglobin performed with the Abbott Vision analyzer. The assay is based on batch affinity-extraction with 3-aminophenylboronic acid-derivatized agarose beads. Reagents are packaged in a disposable test pack. Whole-blood specimens are hemolyzed with saponin within a glass capillary tube inserted into the test pack. The sample is automatically diluted with, mixed with, and separated from the solid-phase reagent. Bichromatic absorbance readings are used to calculate the percentage of hemoglobin bound. Based on the linear correlation between affinity-measured glycohemoglobin and HPLC-measured hemoglobin A1c, the percentage of hemoglobin bound is converted to a "standardized %HbA1c" result by use of regression parameters stored during a calibration run. The combination of affinity methodology with standardization by reference to HPLC produces values directly comparable with those obtained by methods specific for HbA1c. The method produces 10 results within 15 min. The assay operates with CVs < 5%, and the results correlate highly with those by ion-exchange and affinity minicolumn methods, and by ion-exchange HPLC.

Autoanalysis↗
PubMed1992

Standardization of glycohemoglobin determinations in the clinical laboratory: three years of experience.

Measurement of glycohemoglobin has been recommended for the long-term assessment of glycemic control in diabetic patients. Because different analytical methods measure different glycohemoglobin species, it has been difficult to compare results between laboratories. Here we report 3 years of experience with calibration of an affinity chromatography method for measuring total glycohemoglobin (GHb). Calibration was achieved by including in each assay three hemolysate calibrators for which values for HbA1c and GHb had been determined by repeated analyses by high-performance liquid chromatography (HPLC) and affinity chromatography, respectively. Calibration improved interassay precision (CV = 3.20-7.90% and < 5.0% before and after the introduction of calibration, respectively) and eliminated lot-to-lot variability. In 91 samples, HbA1c was estimated by the calibrated affinity chromatography assay and measured by an ion-exchange HPLC method. Estimated and HPLC-measured HbA1c showed no clinically significant differences during 36 months. The high degree of long-term precision, the disappearance of lot-to-lot variability, and the excellent comparability between analytical methods measuring different species of glycated hemoglobins demonstrate the advantages of calibration.

Chromatography, Affinity↗
PubMed1992

Interlaboratory standardization of measurements of glycohemoglobins.

The diversity of methods used to measure glycohemoglobins (GHb) makes it difficult to compare patients' results among laboratories. We reported previously the feasibility of providing comparable results from different assays by use of common calibrators. We here compare results from seven different GHb methods calibrated by use of hemolysates assayed by a precise ion-exchange high-performance liquid-chromatographic (HPLC) method for hemoglobin A1c (HbA1c). Thus, regardless of the GHb species measured by the seven methods, results were referenced to the HbA1c content of the calibrators. Without this calibration, GHb values for single samples varied, e.g., from 4.0% to 8.1% and from 10% to 14.2% in the normal and high ranges, respectively. Calibration decreased between-method variability (single sample ranges of, e.g., 4.8% to 5.4% and 9.4% to 10.2% in the normal and high ranges, respectively) and improved interassay precision. We conclude that this approach to calibration of GHb measurements allows direct comparison of results obtained by different methods and improves precision.

Calibration↗
PubMed1991

Interlaboratory comparison of glycohemoglobin results: College of American Pathologists Survey data.

We describe recent changes in the College of American Pathologists Glycohemoglobin (gHb) Survey, made to improve the assessment of interlaboratory variability and the accuracy of results reported. The questionnaire portion of the survey was revised to include an updated list of current methods, and results for survey specimens were grouped according to the component measured (Hb A1, Hb A1c, or total gHb). The survey specimen material was changed to a material thought to give more reliable results with all available methods. After these changes, instituted in 1989, between-laboratory CVs decreased for some methods. Furthermore, gHb values between method types were more consistent with results obtained from fresh blood samples under very controlled laboratory conditions. However, these recent data also show that the interlaboratory variability is still quite high for some methods and that the variability within and between method types is still very great. We describe a pilot standardization program for gHb measurement.

Chromatography, Affinity↗
PubMed1990

A randomized study of carbon dioxide management during hypothermic cardiopulmonary bypass.

Eighty-six patients undergoing coronary artery bypass graft (n = 63) or intracardiac (n = 23) surgery were randomly assigned with respect to the target value for PaCO2 during cardiopulmonary bypass. In 44 patients the target PaCO2 was 40 mmHg, measured at the standard electrode temperature of 37 degrees C, while in 42 patients the target PaCO2 was 40 mmHg, corrected to the patient's rectal temperature (lowest value reached: mean 30.1, SD 1.9 degrees C). Other salient features of bypass management include use of bubble oxygenators without arterial filtration, flows of 1.8-2.4 l.min-1.m-2, mean hematocrit of 23%, and mean arterial blood pressure of approximately 70 mmHg, achieved by infusion of phenylephrine or sodium nitroprusside. Neuropsychologic function was assessed with series of tests administered on the day prior to surgery, just before discharge from the hospital (mean 8.0, SD 5.8 days postoperatively, n = 82), and again 7 months later (mean 220.7, SD 54.4 days postoperatively, n = 75). The scores at 8 days showed wide variability and generalized impairment unrelated to the PaCO2 group or to hypotension during cardiopulmonary bypass. At 7 months no significant difference was observed in neuropsychologic performance between the PaCO2 groups. Regarding cardiac outcome, there were no significant differences between groups in the appearance of new Q-waves on the electrocardiogram, the postoperative creatine kinase-MB fraction, the need for inotropic or intraaortic balloon pump support, or the length of postoperative ventilation or intensive care unit stay. These findings support the hypothesis that CO2 management during cardiopulmonary bypass at moderate hypothermia has no clinically significant effect on either neurobehavioral or cardiac outcome.

Carbon Dioxide↗
PubMed1990

Lack of relationship between glucose tolerance and complications of pregnancy in nondiabetic women.

Recent studies suggest that gestational diabetes mellitus (GDM) is underdiagnosed. To test this hypothesis, we examined the relationship of perinatal complications to glucose tolerance during the third trimester. Our population consisted of 287 women evaluated at approximately 28 wk gestation who had normal fasting (less than 5.9 mM) and 2-h (less than 9.2 mM plasma glucose) levels after a 100-g glucose load. Glycosylated hemoglobin and glycosylated plasma protein were also measured. Study subjects were stratified into three groups based on 2-h plasma glucose values: group 1 (n = 59) less than 5.6 mM, group 2 (n = 112) 5.6-6.0 mM, and group 3 (n = 116) 6.7-9.2 mM. There were statistically significant but low correlations (r less than 0.20) between 2-h plasma glucose levels and mother's age, body mass index, infant weights, and Apgar scores. There was a significant increasing trend in the proportion of overweight and obese women from groups 1 to 3 (P less than 0.02). There was also a significant trend toward higher birth weights (P = 0.013) and larger proportions of large for gestational age (LGA) babies (P = 0.02) from groups 1 to 3, and women with LGA infants showed higher fasting and 2-h plasma glucose levels than women with non-LGA infants (P = 0.032). However, there was no significant difference in perinatal complications or infant morbidity or mortality between groups. Percentage of glycosylated hemoglobin or glycosylated plasma protein did not differ between groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Neurobehavioral outcomes in cardiac operations. A prospective controlled study.

To assess the severity and duration of new organic brain dysfunction after cardiac operations, we used an extensive battery of neuropsychologic tests to evaluate 65 patients undergoing coronary artery bypass grafting and 25 patients undergoing intracardiac operations with cardiopulmonary bypass. Patients were tested the day before the operation, before discharge from the hospital, and approximately 7 months later. Compared to 47 nonsurgical control subjects tested at comparable time intervals, surgical subjects showed generalized impairment of neuropsychologic abilities near the time of discharge from the hospital. At follow-up testing, there was no evidence of residual impairment among the surgically treated patients as a whole. In fact, they showed greater improvement compared to initial test scores than did control subjects. However, performance of 10 patients (11%) declined on half of the neuropsychologic variables between preoperative and follow-up testing. Neurobehavioral outcome was not related to the type of operation (coronary bypass versus intracardiac), to factors of cardiopulmonary bypass (duration, aortic occlusion time, hypotension, arterial carbon dioxide tension, minimum hematocrit value, minimum temperature). The only predictor of negative outcome was advanced age. We conclude that, although neurobehavioral impairment is common during hospitalization after cardiac operations, the prognosis for eventual full recovery is favorable, although less so among the elderly.

Anxiety↗
PubMed1988

Relationship of glycosylated hemoglobin to oral glucose tolerance. Implications for diabetes screening.

The oral glucose tolerance test (OGTT) for diagnosis of diabetes is inconvenient and requires a great deal of patient cooperation. Glycosylated hemoglobin (GHb), an index of long-term glycemic control, could offer several practical advantages over the OGTT for diabetes screening. We evaluated GHb as a screen for diabetes in 381 adults from a population with a high prevalence of non-insulin-dependent diabetes (Pima Indians). All individuals underwent a standard OGTT (75 g) and were separated into one of three groups: normal (N), impaired glucose tolerance (IGT), or diabetes mellitus (D) based on World Health Organization criteria. HbA1c, a GHb, was measured by highly precise high-performance liquid chromatography (interassay C.V. less than 4%). The normal range for HbA1c was 4.07-6.03% based on the 95% confidence interval for a nondiabetic, mostly Caucasian population. Compared with OGTT, HbA1c was highly specific (91%); an elevated HbA1c usually indicated D or IGT (sensitivity = 85 and 30%, respectively). A normal HbA1c did not, however, exclude a diagnosis of D or IGT. Based on previous epidemiological studies relating plasma glucose to chronic diabetic complications, GHb as measured in this study would properly identify the vast majority of subjects at risk. Long-term studies are necessary to determine the actual risk of complications in individuals with persistently normal HbA1c and D or IGT (based on OGTT).

Adolescent↗
PubMed1986

Collection of blood on filter paper for measurement of glycated hemoglobin by affinity chromatography.

We present data on a filter-paper collection and assay method for measurement of glycated hemoglobin (gHb). Onto filter paper dipped into a solution of glucose oxidase (EC 1.1.3.4) and allowed to dry, approximately 20 microL of capillary blood was spotted. For analysis, we eluted the dried blood spot from the paper by soaking in water for 1 h, then measured the gHb in the eluate by affinity chromatography. Because the gHb significantly increased from day 1 to day 14 of storage, it was necessary to standardize the day of elution from the paper. We found a high correlation between gHb measured from samples stored for 14 days on treated paper and gHb measured by affinity chromatography from frozen whole blood or hemolysates (r = 0.96). This method is convenient, requiring small amounts of blood and little sample handling and assay time, and may be particularly useful in certain situations such as large-scale screening for diabetes.

Blood Specimen Collection↗
PubMed1986

Interlaboratory standardization of glycated hemoglobin determinations.

As the clinical utility of glycated hemoglobin (gHb) measurement increases, so does the need for standardization of values between different methods and different laboratories. Using three different methods, we examined the feasibility of interlaboratory standardization of gHb measurement. A liquid-chromatographic (HPLC) system from our research laboratory was designated the reference method. For gHb standards we used erythrocyte hemolysates prepared from blood samples from nondiabetic and diabetic subjects. Values assigned to each standard were based on the mean of multiple gHb determinations by the HPLC method. A clinical laboratory routinely prepared hemolysates and assayed gHb by commercially available ion-exchange ("mini column") and affinity chromatographic methods. For each assay a standard curve was constructed and gHb values were derived from these curves. Samples analyzed in the clinical laboratory were also analyzed in the research laboratory and the curve-derived values were compared with the HPLC-measured values, to determine the accuracy of our interlaboratory standardization procedure. Correlations were excellent (r = 0.99). The lack of significant differences between calculated and HPLC-measured values indicates that interlaboratory standardization is feasible.

Chromatography, Affinity↗