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Biomedical subjects

C McCray

Publications and source records attributed to C McCray.

8 recordsLinked to original sources
PubMed1993

Relationships between lipoprotein(a), lipids, apolipoproteins, basal and stimulated fibrinolytic regulators, and D-dimer.

In 191 newly referred hyperlipidemic patients, our specific aim was to assess relationships between levels of lipoprotein(a) [Lp(a)], lipids, apolipoproteins, regulators of basal and stimulated fibrinolytic activity, and D-dimer, a measure of in vivo fibrinolysis. Lp(a) levels correlated with none of the measures of basal fibrinolytic regulators or D-dimer. In 25 patients, levels of stimulated regulators of fibrinolytic activity and D-dimer were measured after 10-minute cuff venous occlusion. Lp(a) levels again correlated with none of the stimulated regulators of fibrinolytic activity or D-dimer. However, both basal and stimulated levels of fibrinolytic regulators and D-dimer were closely related to other major risk factors for coronary heart disease (CHD) including triglyceride, apolipoprotein (apo) A1, apo B, Quetelet index (QI), and sex. By stepwise regression in 191 patients, the following standardized partial regression coefficients were significant (P < or = .05), and model R2 and P values were as follows: basal tissue plasminogen activator (tPA) with apo B-.18, with time .17, with QI -.28, R2 = 17%, P < or = .0001; basal plasminogen activator inhibitor (PAI) with apo B..25, with time -.15, with QI .17, R2 = 14%, P < or = .0001; basal alpha 2-antiplasmin with apo A1.14, with apo B.24, with QI.17, with sex .30, R2 = 25%, P < .0001; basal plasminogen with A1.15, with apo B.21, with QI.17, with sex.17, R2 = 15%, P < or = .0001; basal fibrinogen with Lp(a).17, with QI.21, with sex.26, R2 = 14%, P < or = .0001; D-dimer with sex.15, R2 = 21%, P < or = .048. Given the absence of any relationship between Lp(a) levels and inhibition or stimulation of fibrinolysis regulators or D-dimer either in the basal or stimulated state, we postulate that Lp(a)'s major atherogenic effects are mediated by mechanisms other than reduction of fibrinolysis stimulation or in vivo fibrinolysis.

Apolipoproteins↗
PubMed1990

Lack of concordance in classification of coronary heart disease risk: high-risk HDL cholesterol less than 35 mg/dl in subjects with desirable total serum cholesterol, less than 200 mg/dl.

In using National Cholesterol Education Program guidelines (for desirable low risk, a total cholesterol level less than 200 mg/dl, and for high risk, a level of high-density lipoprotein cholesterol (HDLC) less than 35 mg/dl), our specific aim was to examine lack of concordance in classification of coronary heart disease (CHD) risk by HDLC less than 35 mg/dl in subjects with total cholesterol less than 200 and to determine whether lack of concordance increased as group CHD risk increased. We studied four cohorts ranging from putatively low to high CHD risk. These included self-referred subjects in a public urban total cholesterol screening (n = 897), hospitalized patients with depression (n = 144), Cholesterol Center referrals at presumed high CHD risk (n = 1120), and patients having coronary arteriography (n = 145) because of presumed coronary artery disease. Total cholesterol was less than 200 mg/dl in 25% of subjects from the urban sampling, in 54% of hospitalized patients with depression, in 27% of Cholesterol Center referrals, and in 41% of those undergoing cardiac catheterization. In these four cohorts, of subjects with total cholesterol less than 200, 7%, 26%, 25%, and 48%, respectively, had HDLC less than 35 mg/dl. The likelihood of having total cholesterol less than 200 and HDLC less than 35 mg/dl was 1.7% in urban public subjects, 6.8% in Cholesterol Center referrals, 13.9% in depressed patients, and 20% in cardiac catheterization patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Cholesterol↗
PubMed1989

Cholesterol guidelines, lipoprotein cholesterol levels, and triglyceride levels: potential for misclassification of coronary heart disease risk.

By using National Cholesterol Education Program guidelines for serum cholesterol (less than 200 mg/dl is designated "desirable," and 200 to 239 mg/dl is designated "borderline-high," and greater than or equal to 240 mg/dl is designated "high"), low-density and high-density lipoprotein (LDL, HDL) cholesterol levels and triglyceride levels were quantitated in 897 self-referred fasting subjects to assess the potential for coronary risk misclassification. With cholesterol less than 200 mg/dl, misclassification was arbitrarily identified by an LDL level greater than or equal to the 75th percentile, a triglyceride level greater than or equal to the 90th percentile, or an HDL level less than or equal to the 10th percentile. With the cholesterol level in the 200 to 239 mg/dl range, misclassification was identified by an LDL level greater than or equal to the 75th percentile, a triglyceride level greater than or equal to the 90th percentile, and an HDL level less than or equal to the 10th percentile or greater than or equal to the 90th percentile (or both). With a cholesterol level greater than or equal to 240 mg/dl, misclassification was identified by an HDL level less than or equal to the 10th percentile, or greater than or equal to the 90th percentile. With the cholesterol level less than 200 mg/dl, misclassification is rare, occurring in 14.5% of the subjects. With the cholesterol level in the 200 to 239 mg/dl range, and greater than or equal to 240 mg/dl, misclassification occurred in 46.7% and 17.6% of the subjects, respectively. The importance of routine lipoprotein analysis when the cholesterol level is greater than or equal to 240 mg/dl is emphasized by the finding that 65% of the subjects in this category had top quartile LDL levels, 8% had bottom decile HDL levels, and 30% had top decile triglyceride levels. To avoid misclassification, fasting HDL, LDL, and triglyceride levels should probably be measured in all subjects with screening cholesterol levels greater than or equal to 200. There is remarkably little misclassification with top quartile LDL or bottom decile HDL levels (or both) when the cholesterol level is less than 200 mg/dl.

Adolescent↗
PubMed1988

Know your cholesterol: population screening.

To facilitate the goal that all adult Americans know their total serum cholesterol levels, our specific aim was to evaluate the effectiveness, practicality, and cost of total cholesterol sampling in nonfasting self-referred subjects with use of venous blood and mailed results (n = 3844), and to compare these results with capillary blood total cholesterol levels (n = 1167), with immediate turnaround. We used consensus cut points of total cholesterol levels greater than 200, greater than 220, and greater than 240 mg/dl for moderate risk of coronary heart disease and greater than 220, greater than 240, and greater than 260 for high risk for aged 20 through 29, 30 through 39, and greater than 40 years. Total cholesterol level was in the moderate- or high-risk range in 45% and 37% of the venous and capillary cohorts, respectively. Median venous and capillary total cholesterol values were approximately 20 and 10 mg/dl greater than the total cholesterol values in the Lipid Research Clinics Prevalence Study, a difference contributed to by nonfasting versus fasting conditions, use of serum versus plasma, and self-referral bias for subjects with a family history of premature coronary heart disease. The cost per subject in the venous and capillary studies was $5.09 and $7.12 respectively, and $11.40 and $ 18.63 for each subject in the moderate- to high-risk range. Resampling with the subject fasting and follow-up were stressed, and were made available for moderate- and high-risk subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMedDate not supplied

Measurement of lipoprotein (a): comparison of Macra and Imubind methods.

Our specific aim was to compare lipoprotein(a) [Lp(a)] measured by two enzyme-linked immunosorbent assays (the Strategic Diagnostics, Inc. Macra Lp(a) and the American Diagnostica, Inc. Imubind Lp(a) Stripwell) in sequentially referred hyperlipidemic patients. The Macra method binds Lp(a) in serum or plasma to monoclonal anti-Lp(a) in microtiter test wells followed by polyclonal anti-Lp(a) and a chromogenic reaction; the Imubind method is similar but uses two polyclonal anti-Lp(a) antibodies. Within run coefficients of variation were 1.5 percent for the Macra (Lp[a] 27.2 +/- 0.4 mg/dl) and 3.4 percent for the Imubind method (Lp[a] = 18.9 +/- 0.6 mg/dl). Between-run coefficients of variation for the Macra method were 4.7 percent (Lp[a] 14.8 +/- 0.7 mg/dl) and 8.3 percent (Lp[a] of 33.5 +/- 2.8 mg/dl). For the Imubind method in nine separate analytical runs, the between run coefficients of variation were 8.4 percent (Lp[a] of 15.4 +/- 1.3 mg/dl), 3.0 percent (18.8 +/- 0.6 mg/dl), and 5.7 percent (25.6 +/- 1.5 mg/dl). The intraclass correlation was 0.92 (p < or = 0.0001) for duplicate aliquots (n = 210) quantitated by both methods, and the lower limit of the 95 percent confidence interval of the intraclass correlation was 0.90. Comparison of the two methods revealed no systematic bias (p = 0.09), since the lower limit of the 95 percent intraclass correlation confidence interval was > or = 0.75, the two methods for measuring Lp(a) are considered interchangeable. Given the importance of Lp(a) as an independent risk factor for coronary heart disease, it is clinically important to have precise and accurate methods for its measurement.

Adolescent↗