Role of rapid immunoassays for urgent ("stat") determinations of creatine kinase isoenyme MB

We compared the analytical performance of three immunoassays used to rapidly determine creatine kinase (EC 2.7.3.2; CK) isoenzyme MB in serum: Dade's "Stratus," Corning's "Magic Lite," and Hybritech's "Icon QSR CK-MB." Performance criteria included precision, analytical sensitivity, sample stability, and analytical and clinical correlation of results for serum samples taken from healthy individuals, patients with suspected and confirmed acute myocardial infarction, and patients after coronary artery bypass surgery. We also examined 31 samples taken from patients in the emergency room suspected of myocardial infarction, to evaluate the potential of these assays for early diagnosis. Although these assays differ in the manner in which CK-MB is measured, and therefore have different procedural requirements, we conclude that they are equivalent in overall assay performance. None of these assays, however, is sufficiently sensitive for early diagnosis of myocardial infarction; therefore, results cannot be used by cardiologists in deciding whether acute thrombolytic therapy should be given. Other management decisions, such as the optimal utilization of intensive-care bed space, may justify using these assays on a "stat" basis.

Role of rapid immunoassays for urgent ("stat") determinations of creatine kinase isoenyme MB

We compared the analytical performance of three immunoassays used to rapidly determine creatine kinase (EC 2.7.3.2; CK) isoenzyme MB in serum: Dade's "Stratus," Corning's "Magic Lite," and Hybritech's "Icon QSR CK-MB." Performance criteria included precision, analytical sensitivity, sample stability, and analytical and clinical correlation of results for serum samples taken from healthy individuals, patients with suspected and confirmed acute myocardial infarction, and patients after coronary artery bypass surgery. We also examined 31 samples taken from patients in the emergency room suspected of myocardial infarction, to evaluate the potential of these assays for early diagnosis. Although these assays differ in the manner in which CK-MB is measured, and therefore have different procedural requirements, we conclude that they are equivalent in overall assay performance. None of these assays, however, is sufficiently sensitive for early diagnosis of myocardial infarction; therefore, results cannot be used by cardiologists in deciding whether acute thrombolytic therapy should be given. Other management decisions, such as the optimal utilization of intensive-care bed space, may justify using these assays on a "stat" basis.

Creatine kinase isoforms in ischemic heart disease

The MM and MB isoenzymes of creatine kinase exist in serum as a collection of at least three major MM and two major MB isoforms. Each of these are derived from single tissue MM and MB isoforms, which are converted to these other forms by carboxypeptidase N after their release from necrotic skeletal and myocardial tissue. Measurement of the MM isoforms in ischemic heart disease is useful for early diagnosis of acute myocardial infarction and for the noninvasive determination of coronary artery reperfusion for infarction patients receiving thrombolytic therapy. Because MM is also released in acute skeletal-muscle disease, MB isoform measurements may have the highest clinical sensitivity. These determinations are important for providing objective information to cardiologists who need to make critical decisions concerning the management of these patients. I review the procedures for treating patients with myocardial infarction, the potential role of CK isoforms, and the methods currently available for isoform analysis, including high-resolution electrophoresis, isoelectric and chromatofocusing, and liquid chromatography. Rapid and highly sensitive methods are needed for implementation of CK-MM and MB isoforms for prospective emergency determinations for patients with acute myocardial infarction.

Creatine kinase isoforms in ischemic heart disease

The MM and MB isoenzymes of creatine kinase exist in serum as a collection of at least three major MM and two major MB isoforms. Each of these are derived from single tissue MM and MB isoforms, which are converted to these other forms by carboxypeptidase N after their release from necrotic skeletal and myocardial tissue. Measurement of the MM isoforms in ischemic heart disease is useful for early diagnosis of acute myocardial infarction and for the noninvasive determination of coronary artery reperfusion for infarction patients receiving thrombolytic therapy. Because MM is also released in acute skeletal-muscle disease, MB isoform measurements may have the highest clinical sensitivity. These determinations are important for providing objective information to cardiologists who need to make critical decisions concerning the management of these patients. I review the procedures for treating patients with myocardial infarction, the potential role of CK isoforms, and the methods currently available for isoform analysis, including high-resolution electrophoresis, isoelectric and chromatofocusing, and liquid chromatography. Rapid and highly sensitive methods are needed for implementation of CK-MM and MB isoforms for prospective emergency determinations for patients with acute myocardial infarction.

Personal and family history of lung disease as risk factors for adenocarcinoma of the lung

To identify risk factors for adenocarcinoma of the lung, a population-based case-control study of 336 female cancers of this cell type and an equal number of neighborhood controls was conducted between 1983 and 1986. After adjusting for personal smoking, personal and family histories of lung disease emerged as additional risk factors. A personal history of any lung disease was associated with a 40% increase in risk [smoking adjusted relative risk (SARR) = 1.4, 95% confidence interval (CI) = 1.0, 2.0] with a more marked increase in risk for lung diseases occurring during childhood (SARR = 1.9, 95% CI = 1.2, 3.2) and for tuberculosis (SARR = 10.0, 95% CI = 1.1, 90.1). Family histories of tuberculosis (SARR = 2.0, 95% CI = 1.1, 3.6) and of lung cancer (SARR = 3.9, 95% CI = 2.0, 7.6) were also risk factors for adenocarcinoma of the lung. Increasing risk was observed with decreasing intake of dietary beta-carotene. After adjusting for personal smoking, women in the lowest quartile of intake showed a two-fold increased risk relative to those in the highest quartile of intake (P = 0.003). There were also some suggestive differences between cases and controls in their reproductive history and hormone use.

An unusual case of toluene-induced metabolic acidosis

We used gas chromatography-mass spectrometry to analyze serum specimens from a patient whose metabolic ketoacidosis resulted from sniffing a toluene-containing substance; we also analyzed a sample of the abused substance itself and a serum specimen from a normal subject. The blood samples from the patient showed abnormally high concentrations of acetoacetic, azelaic, benzoic, and 3-hydroxybutyric acids, and a smaller amount of hippuric acid than in the control serum. The ketone bodies and benzoic acid appeared to be factors contributing to her acidosis and ketosis. Analysis for volatile solvents in the patient's serum revealed a low concentration of methyl acetate, in contrast to the high concentrations of toluene and bis(2-ethylhexyl) phthalate and the trace concentration of xylene in the abused substance. We consider this case unusual because the presence and concentration of specific ketoacids was unexpected in light of what was known about the patient.

An unusual case of toluene-induced metabolic acidosis

We used gas chromatography-mass spectrometry to analyze serum specimens from a patient whose metabolic ketoacidosis resulted from sniffing a toluene-containing substance; we also analyzed a sample of the abused substance itself and a serum specimen from a normal subject. The blood samples from the patient showed abnormally high concentrations of acetoacetic, azelaic, benzoic, and 3-hydroxybutyric acids, and a smaller amount of hippuric acid than in the control serum. The ketone bodies and benzoic acid appeared to be factors contributing to her acidosis and ketosis. Analysis for volatile solvents in the patient's serum revealed a low concentration of methyl acetate, in contrast to the high concentrations of toluene and bis(2-ethylhexyl) phthalate and the trace concentration of xylene in the abused substance. We consider this case unusual because the presence and concentration of specific ketoacids was unexpected in light of what was known about the patient.

Ionized calcium monitoring during liver transplantation

Ionized calcium concentration was measured in five patients undergoing liver transplantation. Varying degrees of decreased ionized calcium were observed in all cases and can be attributed to the chelation of calcium by the citrate added during blood transfusions, the inability of the patient to metabolize citrate by the liver during the anahepatic phase of the transplant, and hemodilution of the blood volume with the perfusion prime during venovenous bypass. Calcium chloride was administered when necessary as guided by ionized calcium measurements to restore concentrations to levels that maintain adequate cardiac output. Because of the serious hemodynamic consequences of severe hypocalcemia, regular monitoring of ionized calcium concentration is necessary during this procedure. Total calcium levels are not reliable for this because they do not reflect the extent of anion binding.

Role of qualitative choriogonadotropin assays in diagnosis of ectopic pregnancy

We compared the clinical sensitivity and cost-effectiveness of a qualitative assay for choriogonadotropin in human urine ("Icon" hCG) with a quantitative assay of serum from 142 women with pathologically-diagnosed ectopic pregnancy. Results show that although the qualitative assay had a clinical sensitivity for pregnancy of 98.6%, as compared to 100% for the quantitative assay, it was more economical to use, and had a significantly shorter turnaround time. We conclude that qualitative hCG assay of either urine or serum is a good screening method for detecting pregnancy, and can replace the stat quantitative assay in women with suspected ectopic pregnancy. We present a diagnostic algorithm to illustrate the role of qualitative and quantitative hCG assays in conjunction with ultrasonography, culdocentesis, and laparoscopy for diagnosis of ectopic pregnancy.

Role of qualitative choriogonadotropin assays in diagnosis of ectopic pregnancy

We compared the clinical sensitivity and cost-effectiveness of a qualitative assay for choriogonadotropin in human urine ("Icon" hCG) with a quantitative assay of serum from 142 women with pathologically-diagnosed ectopic pregnancy. Results show that although the qualitative assay had a clinical sensitivity for pregnancy of 98.6%, as compared to 100% for the quantitative assay, it was more economical to use, and had a significantly shorter turnaround time. We conclude that qualitative hCG assay of either urine or serum is a good screening method for detecting pregnancy, and can replace the stat quantitative assay in women with suspected ectopic pregnancy. We present a diagnostic algorithm to illustrate the role of qualitative and quantitative hCG assays in conjunction with ultrasonography, culdocentesis, and laparoscopy for diagnosis of ectopic pregnancy.

Automated quantification of choriogonadotropin: analytical correlation between serum and urine with creatinine correction

We evaluated the Boehringer Mannheim Diagnostics ES 600 automated immunoassay system for measuring choriogonadotropin (hCG) in human serum, plasma, and urine. The ES 600, an automated sample-selective, multibatch analyzer, is based on immunoenzymometric coated-tube technology. Interassay CVs for assay of both serum and urine ranged from 2% to 16%. The analytical sensitivity was 0.5 int. unit/L. Results for serum correlated well with qualitative "Icon" and quantitative "Tandem" assays (Hybritech). In addition, results for serum and urinary hCG correlated well when the latter was expressed in terms of creatinine excretion. These results suggest that determination of hCG in urine can be correlated with those in serum for use as a marker for chorionic tumors or for screening abnormal pregnancies, where the rate of hCG production may be important.

Automated quantification of choriogonadotropin: analytical correlation between serum and urine with creatinine correction

We evaluated the Boehringer Mannheim Diagnostics ES 600 automated immunoassay system for measuring choriogonadotropin (hCG) in human serum, plasma, and urine. The ES 600, an automated sample-selective, multibatch analyzer, is based on immunoenzymometric coated-tube technology. Interassay CVs for assay of both serum and urine ranged from 2% to 16%. The analytical sensitivity was 0.5 int. unit/L. Results for serum correlated well with qualitative "Icon" and quantitative "Tandem" assays (Hybritech). In addition, results for serum and urinary hCG correlated well when the latter was expressed in terms of creatinine excretion. These results suggest that determination of hCG in urine can be correlated with those in serum for use as a marker for chorionic tumors or for screening abnormal pregnancies, where the rate of hCG production may be important.

Reassessment of creatine kinase BB as a marker for cancer of the prostate, breast, and lung

We used an enzyme-linked immunoabsorbent assay to measure creatine kinase (CK; EC 2.7.3.2) BB in the sera of 58 cancer patients. A pre-incubation step with an anti-CK-M antibody-coated bead removed M chain components, and CK-BB was quantified with use of an anti-CK-B antibody-coated tube. No cross reactivity was observed with mitochondrial CK or CK-MM; CK-MB cross reacted slightly (1.6%). Macro CK type 1 was measured as CK-BB. Average analytical recovery of purified CK-BB added to serum was 97.7%. Although the enzyme activity of CK-BB is labile, our studies show that this protein is antigenically stable for 12 months when stored frozen. The upper limit of normal for CK-BB concentration was 0.3 micrograms/L (95th percentile, n = 25). Of the 20 cases of breast cancer of various stages, none showed any increases of serum CK-BB. Only two of 18 patients with prostatic carcinoma (stage D), and two of 10 patients with oat-cell carcinoma of the lung had increased concentrations of CK-BB in the serum. Ten patients with squamous cell cancer of the lung had normal concentration of the enzyme. Thus the CK-BB isoenzyme is not frequently increased in cancers of the prostate, lung, and breast, and it has little apparent value as a tumor marker for these diseases.

Reassessment of creatine kinase BB as a marker for cancer of the prostate, breast, and lung

We used an enzyme-linked immunoabsorbent assay to measure creatine kinase (CK; EC 2.7.3.2) BB in the sera of 58 cancer patients. A pre-incubation step with an anti-CK-M antibody-coated bead removed M chain components, and CK-BB was quantified with use of an anti-CK-B antibody-coated tube. No cross reactivity was observed with mitochondrial CK or CK-MM; CK-MB cross reacted slightly (1.6%). Macro CK type 1 was measured as CK-BB. Average analytical recovery of purified CK-BB added to serum was 97.7%. Although the enzyme activity of CK-BB is labile, our studies show that this protein is antigenically stable for 12 months when stored frozen. The upper limit of normal for CK-BB concentration was 0.3 micrograms/L (95th percentile, n = 25). Of the 20 cases of breast cancer of various stages, none showed any increases of serum CK-BB. Only two of 18 patients with prostatic carcinoma (stage D), and two of 10 patients with oat-cell carcinoma of the lung had increased concentrations of CK-BB in the serum. Ten patients with squamous cell cancer of the lung had normal concentration of the enzyme. Thus the CK-BB isoenzyme is not frequently increased in cancers of the prostate, lung, and breast, and it has little apparent value as a tumor marker for these diseases.

Alcohol, physical activity and other risk factors for colorectal cancer: a prospective study

The aetiology of colorectal cancer was studied in a cohort of 11,888 residents of a retirement community. After four and one-half years of follow-up, 58 male and 68 female incident colorectal cancers were identified. Daily alcohol drinkers experienced nearly a two-fold increase in risk (2 sided P = 0.002). Colorectal cancer was also positively associated with Quetelet's index and inversely associated with avocational physical activity. The results were consistent for both sexes but were statistically significant only for males. With the exception of dietary vitamin C, none of the nutrients under study (i.e., vitamins A and E, dietary fibre, calcium, and beta carotene) showed a significant association with colorectal cancer. An inverse relationship between colorectal cancer and dietary vitamin C was observed in females, but there was no association with either vitamin C from supplements or with total vitamin C intake. Males and females who had 3 or more children showed a significantly reduced risk of colorectal cancer (RR = 0.45, 95% CI = 0.2, 0.9), but those with no children did not show the highest risk.

Early diagnosis of acute myocardial infarction by rapid analysis of creatine kinase isoenzyme-3 (CK-MM) sub-types

We compared the clinical sensitivity, specificity, and diagnostic efficiency of measuring creatine kinase-3 (MM) isoenzyme sub-types (CK, EC 2.7.3.2) with the measurement of CK-2 (MB) isoenzymes for the diagnosis of acute myocardial infarction. Serial blood collections at 3-h intervals from 35 patients with acute myocardial infarction were examined. In attempts to reperfuse their coronary arteries, some of these patients were treated with pharmacological thrombolysis (streptokinase, tissue plasminogen activator), with or without coronary angioplasty. The infarction patients were divided into two groups: patients who were successfully treated with thrombolytic agents (i.e., they achieved coronary reperfusion), and patients who were treated unsuccessfully or who were not treated acutely. We also examined blood from 34 non-infarction patients. We measured CK-3 sub-types by both anion-exchange liquid chromatography and a modified high-voltage electrophoresis method, and CK-2 by immunoprecipitation. Our results show that during the first few critical 3 to 9 h after onset of chest pain, measurement of CK-3 sub-types has the highest diagnostic efficiency; in contrast, CK-2 has the highest efficiency during the 10- to 21-h time intervals. Thus early diagnosis of acute myocardial infarction can be based on rapid assays of CK-3 sub-types.

Platelet dysfunction associated with Wilms tumor and hyaluronic acid

Acquired von Willebrand disease (AVWD) has been described in two cases of nephroblastoma. We studied a patient with nephroblastoma who presented with a coagulopathy suggestive of AVWD. The subject had undetectable levels of F.VIIIR:Ag, diminished F.VIIIR:WF (16.3%), F.VIII:C activity (37%), and lack of platelet aggregation to ADP, epinephrine, collagen, and arachidonic acid. These results were associated with abnormally high serum levels (850 mg/dl) of hyaluronic acid (HA), which made the patient's serum hyperviscous. Examination of the neoplasm revealed HA in the tumor matrix. All abnormalities of coagulation resolved after chemotherapy and extirpation of the neoplasm, which produced normal serum HA levels. To study the effects of HA on platelet function, we added HA to normal platelet-poor plasma (NPP), which rendered F.VIIIR:Ag undetectable; treatment of HA with hyaluronidase eliminated F.VIIIR:Ag assay interference caused by HA. F.VIII:C activity decreased in vitro when HA was mixed with normal platelet-poor plasma (NPP). HA reduced the initial slope of normal platelet aggregation. Partial correction of platelet aggregation occurred after hyaluronidase treatment of HA-spiked PRP. Experiments in rabbits exposed to HA (serum level 400 mg/dl) demonstrated abnormalities similar to those noted in the patient. Shear rate studies of whole blood containing HA (500 mg/dl) yielded high shear stress, 27-136 dynes/cm2 over shear rates of 10-216 sec-1. We conclude that the coagulopathy demonstrated in this case is secondary to hyperviscosity produced by elevated levels of HA, which interferes with the assay for F.VIIIR:Ag. Thus the acquired coagulopathy associated with other cases of nephroblastoma may present as spurious von Willebrand disease.

Early diagnosis of acute myocardial infarction by rapid analysis of creatine kinase isoenzyme-3 (CK-MM) sub-types

We compared the clinical sensitivity, specificity, and diagnostic efficiency of measuring creatine kinase-3 (MM) isoenzyme sub-types (CK, EC 2.7.3.2) with the measurement of CK-2 (MB) isoenzymes for the diagnosis of acute myocardial infarction. Serial blood collections at 3-h intervals from 35 patients with acute myocardial infarction were examined. In attempts to reperfuse their coronary arteries, some of these patients were treated with pharmacological thrombolysis (streptokinase, tissue plasminogen activator), with or without coronary angioplasty. The infarction patients were divided into two groups: patients who were successfully treated with thrombolytic agents (i.e., they achieved coronary reperfusion), and patients who were treated unsuccessfully or who were not treated acutely. We also examined blood from 34 non-infarction patients. We measured CK-3 sub-types by both anion-exchange liquid chromatography and a modified high-voltage electrophoresis method, and CK-2 by immunoprecipitation. Our results show that during the first few critical 3 to 9 h after onset of chest pain, measurement of CK-3 sub-types has the highest diagnostic efficiency; in contrast, CK-2 has the highest efficiency during the 10- to 21-h time intervals. Thus early diagnosis of acute myocardial infarction can be based on rapid assays of CK-3 sub-types.

Secular trends in histologic types of lung cancer

The histology pattern of lung cancer in Los Angeles County was reviewed for a 10-year period, 1972-81. In men, the total lung cancer incidence has been fairly constant, but there has been a shift in the histology pattern with an increase in adenocarcinoma and a decrease in "other" cell type (i.e., carcinoma not otherwise specified, large-cell and undifferentiated tumors). This changing histology pattern may be partly due to changes in diagnostic standards and practices. With the assumption that these changes are comparable in men and women, the "true" annual rate of change was estimated for each lung cancer cell type in women. All lung cancer types have increased in women; of the cell types squamous cell carcinoma, small-cell carcinoma, and adenocarcinoma, small-cell carcinoma showed the largest rate of annual increase and adenocarcinoma, the smallest.

Bilirubin interference with determination of uric acid, cholesterol, and triglycerides in commercial peroxidase-coupled assays, and the effect of ferrocyanide

We examined the effect of bilirubin on measurement of serum uric acid, cholesterol, and triglyceride in the BMD-8700, Hitachi 705, Multistat III, CentrifiChem, Cobas-Bio, Ektachem 400, aca II, and RA-1000 analyzers. In general, bilirubin interferes more in peroxidase-coupled assays than in either direct methods or those coupled to NAD(P)+. The degree of interference, which can be spectral or chemical, varies and depends on the chromogen and wavelength used. We present data to show the origin and extent of the interference by bilirubin in these systems and demonstrate how ferrocyanide can provide a satisfactory resolution in some cases.

Bilirubin interference with determination of uric acid, cholesterol, and triglycerides in commercial peroxidase-coupled assays, and the effect of ferrocyanide

We examined the effect of bilirubin on measurement of serum uric acid, cholesterol, and triglyceride in the BMD-8700, Hitachi 705, Multistat III, CentrifiChem, Cobas-Bio, Ektachem 400, aca II, and RA-1000 analyzers. In general, bilirubin interferes more in peroxidase-coupled assays than in either direct methods or those coupled to NAD(P)+. The degree of interference, which can be spectral or chemical, varies and depends on the chromogen and wavelength used. We present data to show the origin and extent of the interference by bilirubin in these systems and demonstrate how ferrocyanide can provide a satisfactory resolution in some cases.

Lung cancer in women living in the Pacific Basin area

We compared recent incidence rates for lung cancer in females among several regions in the Pacific Basin, Shanghai, Hong Kong, Miyagi, Hawaii, and Los Angeles, by ethnic group using data from the population-based registry in each area. The rates were high among whites and Hawaiians, intermediate in Chinese, and low in Japanese regardless of area. The risk of lung cancer among females who smoke relative to that in female nonsmokers varied from 1 ethnic group to another as did the proportion of smokers in the populations studied. Most of the interethnic differences in lung cancer incidence rates could be explained by differences in smoking patterns. The estimated annual incidence rate for lung cancer in females after subtraction of the proportion of the incidence due to smoking was 7.5/100,000 population in every ethnic group except the Chinese (15-20/100,000 population). Most of the residual incidences of lung cancer were adenocarcinoma of the lung.

Measurement of creatine kinase MM sub-type by anion-exchange liquid chromatography

Electrophoretic and isoelectric focusing studies have demonstrated the presence of multiple sub-forms of the major creatine kinase isoenzymes, and preliminary work has suggested that measurement of the mm sub-forms provides early diagnostic information concerning acute myocardial infarction. We developed an isocratic method based on liquid chromatography to examine further the clinical potential of measuring these sub-forms. An anion-exchange column is used coupled with the fluorometric detection of NADPH after reaction of the sub-forms with CK reagents, which are added through a post-column pump. We examined various chromatographic variables in producing the best separations. Results for blood collected from normal individuals and patients with acute myocardial infarction and skeletal muscle diseases are compared. We conclude that for routine CK-MM sub-form analysis, this chromatographic procedure is better suited than isoelectric focusing because of the faster turn-around and lower costs.

Measurement of creatine kinase MM sub-type by anion-exchange liquid chromatography

Electrophoretic and isoelectric focusing studies have demonstrated the presence of multiple sub-forms of the major creatine kinase isoenzymes, and preliminary work has suggested that measurement of the mm sub-forms provides early diagnostic information concerning acute myocardial infarction. We developed an isocratic method based on liquid chromatography to examine further the clinical potential of measuring these sub-forms. An anion-exchange column is used coupled with the fluorometric detection of NADPH after reaction of the sub-forms with CK reagents, which are added through a post-column pump. We examined various chromatographic variables in producing the best separations. Results for blood collected from normal individuals and patients with acute myocardial infarction and skeletal muscle diseases are compared. We conclude that for routine CK-MM sub-form analysis, this chromatographic procedure is better suited than isoelectric focusing because of the faster turn-around and lower costs.

Smoking and other risk factors for lung cancer in women

A case-control study among white women in Los Angeles County was conducted to investigate the role of smoking and other factors in the etiology of lung cancer in women. A total of 149 patients with adenocarcinoma (ADC) and 71 patients with squamous cell carcinoma (SCC) of the lung and their age- and sex-matched controls were interviewed. Personal cigarette smoking accounted for almost all of SCC and about half of ADC in this study population. Among nonsmokers, slightly elevated relative risk(s) (RR) for ADC were observed for passive smoke exposure from spouse(s) [RR = 1.2; 95% confidence interval (Cl) = 0.5, 3.3] and at work (RR = 1.3; 95% Cl = 0.5, 3.3). Childhood pneumonia (RR = 2.7; 95% Cl = 1.1, 6.7) and childhood exposure to coal burning (RR = 2.3; 95% Cl = 1.0, 5.5) were additional risk factors for ADC. For both ADC and SCC, increased risks were associated with decreased intake of beta-carotene foods but not for total preformed vitamin A foods and vitamin supplements.

Comparison of enzyme immunoassay and immunoprecipitation for creatine kinase MB in diagnosis of acute myocardial infarction

We compared the clinical performance of measuring creatine kinase (EC 2.7.3.2) isoenzyme MB by use of an enzyme immunoassay (Enzygnost CK-MB, Behring Diagnostics) with an immunoprecipitation method (Isomune-CK, Roche Diagnostics) for the diagnosis of acute myocardial infarction. Sera from 80 patients admitted to the coronary care unit because of chest pain were examined: 40 who had this diagnosis of myocardial infarction, and 40 in whom it was ruled out. In addition, sera from 40 apparently healthy individuals were examined. The clinical sensitivity and specificity of these methods were evaluated by use of receiver operating characteristic curves. We conclude that for clinical efficiency, this enzyme immunoassay is slightly superior to the immunoprecipitation assay we used, because of its greater analytical sensitivity and precision for measuring the mass of the isoenzyme.

Comparison of enzyme immunoassay and immunoprecipitation for creatine kinase MB in diagnosis of acute myocardial infarction

We compared the clinical performance of measuring creatine kinase (EC 2.7.3.2) isoenzyme MB by use of an enzyme immunoassay (Enzygnost CK-MB, Behring Diagnostics) with an immunoprecipitation method (Isomune-CK, Roche Diagnostics) for the diagnosis of acute myocardial infarction. Sera from 80 patients admitted to the coronary care unit because of chest pain were examined: 40 who had this diagnosis of myocardial infarction, and 40 in whom it was ruled out. In addition, sera from 40 apparently healthy individuals were examined. The clinical sensitivity and specificity of these methods were evaluated by use of receiver operating characteristic curves. We conclude that for clinical efficiency, this enzyme immunoassay is slightly superior to the immunoprecipitation assay we used, because of its greater analytical sensitivity and precision for measuring the mass of the isoenzyme.

Preparation of urine samples for liquid-chromatographic determination of catecholamines: bonded-phase phenylboronic acid, cation-exchange resin, and alumina adsorbents compared

We compared results for the liquid-chromatographic determination of free norepinephrine and epinephrine in urine after purifying the catechols by the following methods: (a) acid-washed alumina, (b) weak cation-exchange resin (WCX), (c) a combination of weak cation-exchange resin followed by alumina (WCX-alumina), and (d) commercially available phenylboronic acid adsorbent. We evaluated analytical specificity, sensitivity, recovery, and turnaround time. The WCX-alumina combination produced the most sensitive and specific chromatograms for urinary catecholamines; the other methods took less processing time. Neither WCX nor alumina alone was suitable for routine work because of chromatographic interferences in a significant proportion of urines. The phenylboronic acid method is adequately sensitive and specific for norepinephrine and epinephrine, and samples can be assayed faster. Thus it provides a compromise between the high analytical performance of the WCX-alumina method and the speed of the WCX and alumina methods.

Preparation of urine samples for liquid-chromatographic determination of catecholamines: bonded-phase phenylboronic acid, cation-exchange resin, and alumina adsorbents compared

We compared results for the liquid-chromatographic determination of free norepinephrine and epinephrine in urine after purifying the catechols by the following methods: (a) acid-washed alumina, (b) weak cation-exchange resin (WCX), (c) a combination of weak cation-exchange resin followed by alumina (WCX-alumina), and (d) commercially available phenylboronic acid adsorbent. We evaluated analytical specificity, sensitivity, recovery, and turnaround time. The WCX-alumina combination produced the most sensitive and specific chromatograms for urinary catecholamines; the other methods took less processing time. Neither WCX nor alumina alone was suitable for routine work because of chromatographic interferences in a significant proportion of urines. The phenylboronic acid method is adequately sensitive and specific for norepinephrine and epinephrine, and samples can be assayed faster. Thus it provides a compromise between the high analytical performance of the WCX-alumina method and the speed of the WCX and alumina methods.

Hyperviscosity caused by hyaluronic acid in serum in a case of Wilms' tumor

We describe the case of a three-year-old girl with Wilms' tumor, whose serum showed at least a fivefold increase in relative viscosity although concentrations of albumin and immunoglobulins were normal. An unusual electrophoretogram of serum protein prompted further investigation. The increased viscosity was caused by the presence of high concentrations of hyaluronic acid, a glycosaminoglycan normally not detectable in serum.

Hyperviscosity caused by hyaluronic acid in serum in a case of Wilms' tumor

We describe the case of a three-year-old girl with Wilms' tumor, whose serum showed at least a fivefold increase in relative viscosity although concentrations of albumin and immunoglobulins were normal. An unusual electrophoretogram of serum protein prompted further investigation. The increased viscosity was caused by the presence of high concentrations of hyaluronic acid, a glycosaminoglycan normally not detectable in serum.

Coding assignments of each mRNA synthesized in vitro and protein components of CPV of silkworm Bombyx mori

The coding properties of each mRNA synthesized in vitro of CPV have been examined. The mRNAs were separated by polyacrylamide gel electrophoresis and isolated from the gel slices. The individual mRNA was then translated into the wheat germ cell-free protein synthesizing system. The products of translation were analyzed by the immuno-reaction with the 125I-IgG of each of the five electrophoretic protein components of CPV. The coding assignments were deduced on the basis of the immuno-reaction as follows: mRNA1, mRNA3 and mRNA9 encode group P1 of viral proteins, mRNA2 and mRNA6 encode group P2 and P3, respectively. mRNA7 and mRNA8 encode group P4 while mRNA9 encode group P5. There are more than 10 polypeptides in the CPV virion as demonstrated by two-dimensional electrophoresis.

Macro creatine kinase types 1 and 2: clinical significance in neonates and children as compared with adults

We examined the case histories of seven pediatric patients (ages four days to 12 years) whose sera showed significant activities of "macro" creatine kinase (CK; EC 2.7.3.2): two cases of macro CK type 1 (CK-BB isoenzyme bound to IgG) and five cases of macro CK type 2 (polymeric complexes of mitochondrial CK). The diagnoses of the two children with macro CK type 1 were similar to those in 55 adult patients with this form of CK found earlier during screening of a population of 5000. Macro CK type 1 has generally been noted only in older women; this is the first report of it in children. In four of the five cases of macro CK type 2 we found in children, myocardial muscle damage was clinically evident. In contrast, the 26 cases of adults with macro CK type 2 found during the same screening generally had neoplasms, most with metastases to the liver. We suggest that the finding of macro CK type 2 is an indicator of cellular necrosis; in pediatric cases with myocardial damage the associated conditions may be reversible but in adults with malignancies the finding is associated with an extremely poor prognosis.

Macro creatine kinase types 1 and 2: clinical significance in neonates and children as compared with adults

We examined the case histories of seven pediatric patients (ages four days to 12 years) whose sera showed significant activities of "macro" creatine kinase (CK; EC 2.7.3.2): two cases of macro CK type 1 (CK-BB isoenzyme bound to IgG) and five cases of macro CK type 2 (polymeric complexes of mitochondrial CK). The diagnoses of the two children with macro CK type 1 were similar to those in 55 adult patients with this form of CK found earlier during screening of a population of 5000. Macro CK type 1 has generally been noted only in older women; this is the first report of it in children. In four of the five cases of macro CK type 2 we found in children, myocardial muscle damage was clinically evident. In contrast, the 26 cases of adults with macro CK type 2 found during the same screening generally had neoplasms, most with metastases to the liver. We suggest that the finding of macro CK type 2 is an indicator of cellular necrosis; in pediatric cases with myocardial damage the associated conditions may be reversible but in adults with malignancies the finding is associated with an extremely poor prognosis.

Evaluation and comparison of immunoinhibition and immunoprecipitation methods for differentiating MB and BB from macro forms of creatine kinase isoenzymes in patients and healthy individuals

We compared results for measurements of creatine kinase isoenzyme MB (CK-MB) by immunoinhibition vs immunoprecipitation, using sera from 53 normal healthy individuals, 55 patients with increased CK-MB associated with acute myocardial infarction, and 42 patients whose blood exhibited one or more abnormal forms of CK by electrophoresis. These last 42 patients, selected from a group of 91 cases exhibiting abnormal forms as detected in a screening of 5000 hospitalized and clinic patients, include: (a) CK-BB bound to IgG (macro CK type 1), (b) a polymeric complex of mitochondrial CK (macro CK type 2), (c) abnormally high activity of free CK-BB isoenzyme, and (d) persistent increases of CK-MB from patients without myocardial infarction. These abnormal forms occur in less than 2% of all patients and are exceedingly rare in patients with acute myocardial infarction. Therefore, the vast majority of CK-MB analyses can be performed rapidly and efficiently by immunoinhibition, which has analytical sensitivity, is associated with high clinical sensitivity, and is easily automated for a low cost per test. In contrast, immunoprecipitation is a more specific analytical measurement of CK-MB but is less efficient and more costly.

Evaluation and comparison of immunoinhibition and immunoprecipitation methods for differentiating MB and BB from macro forms of creatine kinase isoenzymes in patients and healthy individuals

We compared results for measurements of creatine kinase isoenzyme MB (CK-MB) by immunoinhibition vs immunoprecipitation, using sera from 53 normal healthy individuals, 55 patients with increased CK-MB associated with acute myocardial infarction, and 42 patients whose blood exhibited one or more abnormal forms of CK by electrophoresis. These last 42 patients, selected from a group of 91 cases exhibiting abnormal forms as detected in a screening of 5000 hospitalized and clinic patients, include: (a) CK-BB bound to IgG (macro CK type 1), (b) a polymeric complex of mitochondrial CK (macro CK type 2), (c) abnormally high activity of free CK-BB isoenzyme, and (d) persistent increases of CK-MB from patients without myocardial infarction. These abnormal forms occur in less than 2% of all patients and are exceedingly rare in patients with acute myocardial infarction. Therefore, the vast majority of CK-MB analyses can be performed rapidly and efficiently by immunoinhibition, which has analytical sensitivity, is associated with high clinical sensitivity, and is easily automated for a low cost per test. In contrast, immunoprecipitation is a more specific analytical measurement of CK-MB but is less efficient and more costly.

Microcomputer controlled titration for determination of protein nitrogen in feeds and wheat

The determination of protein nitrogen in feeds and wheat by microcomputer controlled titration is described. The method involves direct titration of ammonia with standard hypochlorite titrant in the presence of bromide. The titrant is delivered by an automatic buret, and the microcomputer controlled, automatically computed potentiometric end points are precise to 0.1% over a 5-fold concentration range of nitrogen. Digestions performed with both mercury and copper catalysts show comparable results. Samples are weighed before digestion by an electronic balance interfaced to the computer which records sample number and weight. An automatic pipet aliquots, dilutes, and buffers samples directly from the digestion tubes; the samples can be immediately titrated with the automatic titrator. The results for protein in NBS standards and check feed samples from an offical testing program compare closely with average values reported for these standards. Results show that feed and wheat samples contained 10-100% protein. Precision for successive aliquots of the same digests is 0.1-0.4%relative standard deviation; precision for multiple digestions of the same sample is 0.1-0.8%.