Effects of Weight Reduction, Exercise, and Diet Modification on Lipids and Apolipoproteins A-l and B in Severely Obese Persons

We assessed the lipid and apolipoprotein effects of hypocaloric dieting, increased physical activity, and dietary modification in severely overweight adults (body mass index [BMI] 43.05 kg/m-). The 34 women and four men enrolled in the ambulatory weight control program donated blood before, during, and after hypocaloric dieting (420 kcal/day). Mean values before dieting included cholesterol of 223 mg/dL, high-density lipoprotein (HDL) cholesterol of 43 mg/dL, and cholesterol/HDL cholesterol of 5.90. This placed our subjects at high risk for coronary artery disease. Other values included triglycerides of 138 mg/dL, apolipoprotein A-l of 152 mg/dL. and apolipoprotein B/apolipoprotein A-l of 0.64. Significant reductions during hypocaloric dieting included mean cholesterol of 171 mg/dL, triglycerides of 99 mg/dL. and apolipoprotein A-l of 120 mg/dL. During weight maintenance (mean BMI 36.08 kg/m²). significant reductions compared to baseline included a mean cholesterol of204 mg/dL and cholesterol/HDL cholesterol of 4.60. Also, a significant increase occurred in HDL cholesterol (51 mg/dL). but a nonsignificant elevation was observed in apolipoprotein A-l (180 mg/dL). In four subjects, discordant ratios of cholesterol/HDL cholesterol or apolipoprotein B/apolipoprotein A-1 were seen. and one ratio improved in two subjects despite relapse of obesity. Changes in both HDL composition and HDL particle concentration may explain elevations of HDL cholesterol and apolipoprotein A-l after dieting. Discordance between lipid and apolipoprotein ratios may occur. Improvement in lipids or apolipoproteins may be seen despite regained weight

Biochemical Diagnosis of Myocardial Infarction

A rapid, sensitive, and specific marker for the diagnosis of acute myocardial infarction (MI) and the assessment of reperfusion following thrombolytic therapy has been sought by research workers for years. Creatine kinase-MB (CK-MB) is the best biochemical marker currently available to the cardiologist and the emergency room physician for the assessment of patients presenting with symptoms of acute Ml. CK-MB is best measured using immunoassay techniques at 3- to 4-hour time intervals during the first 12 hours after onset of.symptoms. Other currently available markers include lactate dehydrogenase and its isoenzymes and myoglobin. Future developments include assays for troponin, reported to be a true cardiac-specific marker, and myosin light chains which may have value in noninvasive infarct sizing

Isoenzyme Update: Creatine kinase and lactate dehydrogenase

Creatine kinase (CK) and lactate dehydrogenase (LD) are isoenzymes that have been measured in clinical laboratories for over 20 years; their separation has proved valuable in the diagnosis of myocardial infarction and other cardiac-related diseases. Although, historically, electrophoresis was the preferred method to measure both isoenzymes, there has been controversy over the best method for separating the CK isoenzyme. lon exchange chromatography has been used successfully to isolate CK isoenzymes, and the procedure was adapted to determine CK-MB activity in serum. New methods to quantify CK-MB have also been tested, including an automated column technique, the immunoinhibidon/ immunoprecipitadon technique, and immunoradiometry. In addition, new immunological techniques have recently been developed to analyze LD isoenzymes; the assay for LD-1 has already replaced electrophoresis. In time, specific assays for CK-MB will also be available. However, new techniques have not eliminated the need to order CK-MB and LD-1 as a battery and to employ appropriate timing and serial collection of samples