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Biomedical subjects

C R Roe

Publications and source records attributed to C R Roe.

At least 109 records · Page 6Linked to original sources

Acute myocardial infarction and MB creatine phosphokinase. Relationship between onset of symptoms of infarction and appearance and disappearance of enzyme.

Sixty-six patients admitted to the coronary care unit within 12 hours of the onset of symptoms of acute myocardial infarction (AMI) were subjected to blood sampling at one- to two-hour intervals for analysis of creatine phosphokinase (CPK) and lactic dehydrogenase (LDH) enzymes and isoenzymes. Complete MB CPK curves were obtained in 27 patients, and these were analyzed for optimum times for sampling and minimum number of analyses for detection of AMI. The present study indicates that (1) optimum detection of AMI can be achieved by analysis for MB CPK in a minimum of two samples obtained at 12 and 24 hours after onset of symptoms of AMI; (2) negative results of analyses for MB CPK in samples obtained before 12 hours or after 24 hours should not be used to exclude the diagnosis of AMI; and (3) a total CPK value within the normal range is not a reliable screening test to exclude analysis of MB CPK.

Acute Disease↗

Hepatic enzymes of tyrosine metabolism in tyrosinemia II.

A middle-aged adult male with a mild form of tyrosinemia II (Richner-Hanhart syndrome) is described. Treatment with a low-tyrosine diet caused a fall in plasma tyrosine and clearing of the hyperkeratosis of the soles. Liver biopsy of this patient revealed low but measurable levels of cytoplasmic tyrosine aminotransferase and elevated levels of the mitochondrial tyrosine-metabolizing enzyme aspartate aminotransferase. It is hypothesized that these enzymes have been induced in sufficient amounts to account for the mild clinical course.

Amino Acid Metabolism, Inborn Errors↗

Relation of creatine kinase isoenzyme MB to postoperative electrocardiographic diagnosis in patients undergoing coronary-artery bypass surgery.

We compared (a) the frequency of detection of isoenzyme MB of creatine kinase (CK; EC 2.7.3.2) in serum of patients undergoing coronary-artery bypass surgery, (b) the interval during uhich its activity was supranormal in serum, and (c) an index of the amount of CK released into blood ("CK-MB area") with postoperative electrocardiographic changes in 80 patients. The frequency of detection of CK-MB is a function of frequency of sampling during the early postoperative period. Because the duration of appearance and the calculated CK-MB area increased as the electrocardiogram became more specific for infarction (p less than 0.01), a twice-daily sampling schedule proved clinically relevant. Only 5.4% of patients had electrocardiographic evidence of infarction when CK-MB was absent by the second postoperative morning. When CK-MB was still detected at that time, 69.6% of patients had persistent new Q waves, consistent with infarction. In three patients who died postoperatively, significant myocardial necrosis was demonstrated. All three had had persistently increased values for CK-MB, related to electrocardiographic changes of infarction in one patient and ischemic changes in two. Evidently CK-MB is a more sensitive indicator of myocardial necrosis than the electrocardiogram and CK-MB area should be a useful criterion in evaluating methods of intra-operative myocardial protection.

Coronary Artery Bypass↗

Importance of blood-collection tubes in plasma lidocaine determinations.

In 25 clinical samples serum lidocaine concentrations fell from a mean of 6.5 +/- 2.1 mg/L (mean +/- SD) to 4.9 +/- 1.8 mg/L (p less than 0.001) when the blood sample was allowed to make contact with the stopper of the Vacutainer collection tube. In vitro experiments showed that this effect of the stopper occurred only with whole blood and was dependent on sample concentration. The plasma binding of lidocaine decreased from a normal value of 56% +/- 2.2 (mean +/- SD) to 28% +/- 2.2 (p less than 0.001) when exposed to the Vacutainer stopper. We conclude that a chemical leached from such stoppers displaces lidocaine from its plasma-binding sites and that the drug is then redistributed into the erythrocytes, producing spuriously low lidocaine concentrations in plasma or serum. Such artifacts are important in therapeutic drug monitoring and can lead to erroneous clinical decisions.

Disposable Equipment↗

Pedigree testing in Duchenne muscular dystrophy.

Female relatives of 41 Duchenne muscular dystrophy proband cases were studied with a panel of carrier-detection tests. A total of 277 relatives were tested in order to determine which mothers had affected sons as a result of new mutation. In 39 of 41 pedigrees the data demonstrate that a mutation cannot be postulated; the 2 megative pedigrees were inadequately tested. Our data suggest that all mothers of affected sons should be considered genetic carriers (heterozygotes) until proved otherwise. Our findings also raise questions concerning what mechanisms skew the indirect statistical estimates of mutation that are in common use.

Adolescent↗

Diagnostic and prognostic significance of electrocardiographic and CPK isoenzyme changes following coronary bypass surgery: correlation with findings at one year.

The incidence of ECG (14 per cent) indication of acute myocardial infarction complicating coronary artery bypass surgery is documented, corroborating the findings of prior series. An additional 32 per cent of patients had appearance of myocardial specific CPK-MB in serum during the immediate postoperative period. All patients surviving to 1 year following surgery (93 of 103) were asked to return for repeat cardiac catheterization to determine the presence and extent of interim ventricular contraction abnormalities. Sixty-five (70 per cent) of the group returned for evaluation. Preoperative and 1 year postoperative left ventriculograms were compared to determine if new contraction abnormalities would confirm the specificity of perioperative QRS and isoenzyme changes, and if the absence of new abnormalities would confirm their sensitivity. The majority of patients (65 per cent) had new areas of asynergy. However, 73 per cent of these were confined to the apex and thus could have been produced by the vent employed during cardiopulmonary bypass. QRS changes were 100 per cent specific and CPK-MB appearance was 78 per cent specific but they were only 20 and 54 per cent sensitive, respectively. Indeed, 46 per cent of those with new asynergy which was non apical had neither QRS change nor CPK-MB appearance. Thus QRS changes were always--and CPK-MB appearance was usually--associated with new asynergy but, in addition, many patients with no perioperative indication of infarction developed new areas of left ventricular contraction abnormality within the first postoperative year.

Angina Pectoris↗

The relationship between enzymatic and histologic estimates of the extent of myocardial infarction in conscious dogs with permanent coronary occlusion.

Relationships between enzyme estimates (EE) and histologic measurements of infarct size (HIS) were analyzed in 14 conscious dogs with permanent occlusion of the circumflex coronary artery. EE were derived from serial CPK, CPK-MM, CPK-MB, and CPK-BB. Estimates were obtained using methods of Shell et al., Norris et al., and Roberts et al. HIS was determined from multiple histologic sections 5-6 days after infarction. In 14 animals, HIS ranged from 0.1-26.6 grams. Regression analysis demonstrated poor correlation (r2 less than 0.06) between EE by each method and HIS. Using the Shell method and restricting the analysis to HIS of less than 13 grams, improved the correlation (r2 = 0.42). Correlation in this subgroup could be further improved by using CPK-MM and MB data, elimination of animals with high background values, or limiting analysis to the portion of the curve where LDH isoenzymes indicated a cardiac zone. When the analysis was restricted to animals with HIS of less than 13 grams, Norris and Roberts modifications as compared to Shell's method improved correlation with CPK-MB but reduced correlation using CPK and CPK-MM data. In this subgroup, each method overestimated extent of HIS; Shell greater than Norris greater than Roberts. In this study it was not possible to distinguish small from large HIS by serum enzyme measurements.

Animals↗

Lactate dehydrogenase isoenzyme in detecting carriers of Duchenne muscular dystrophy.

Thirty mothers of patients with Duchenne muscular dystrophy were studied with serum enzyme tests, including serum glutamic-oxaloacetic transminase, creatine kinase, and lactate dehydrogenase isoenzymes. In addition, females from the mothers' pedigrees were studied. Lactate dehydrogenase isoenzyme 5 determinations were as senitive an indicator of carrier status as creatine kinase and also identified several mothers who had normal dehydrogenase isoenzyme 5 determinations, as well as extensive pedigree testing, identified 28 to 30 mothers as probable heterozygotes. These data independently support the suggestion that cases of Duchenne muscular dystrophy as a result of spontaneous mutation are more uncommon than currently accepted.

Adult↗

Diagnosis of acute myocardial infarction in a community hospital: significance of CPK-MB determination.

Twice-daily CPK-MB determinations were performed but not made availabe to the physicians of 179 consecutive patients with precordial pain admitted to a community hospital to evaluate the diagnostic importance of this isoenzyme. Physician decision was based upon history and once-daily ECG and total enzymes (CPK, SGOT, LDH). Following hospital discharge, each patient's clinical record was reviewed to determine the physician diagnostic decision. The patients were subdivided into three groups. The first group consisted of 46 patients with diagnostic QRS changes and elevated total enzymes. All 46 had physician diagnosis of acute myocardial infarction and CPK-MB was present in 44 (96%). The second group included 55 patients with nondiagnostic QRS but elevated total enzymes. Physician diagnosis was acute myocardial infarction in 28 (51%) but 16 (57%) of these had no CPK-MB. The third group contained 50 patients with nondiagnostic QRS and normal enzyme levels. Six (12%) had physician diagnosis of acute myocardial infarction but none had CPK-MB. Thus, absence of CPK-MB failed to confirm physician diagnosis of acute myocardial infarction when based upon history and total enzymes in the absence of QRS changes in 22 of 34 (65%) patients.

Acute Disease↗

Persistence of MB isoenzyme of creatine phosphokinase in the serum after minor iatrogenic cardiac trauma. Absence of postmortem evidence of myocardial infarction.

The specificity of serum CPK-MB for acute myocardial infarction was examined by retrospective analysis of 401 consecutive patients admitted to Coronary Care Unit over a three and one-half year period with suspected infarction in whom the isoenzyme was subsequently detected. Four patients (1 per cent) who died during the hospital admission had no autopsy evidence of acute myocardial infarction. All four had experienced mild iatrogenic cardiac trauma, following which serum CPK-MG persisted for at least 24 hours. In one patient, a permanent pacemaker had been inserted by the transmediastinal approach. Two patients had been subjected to closed chest cardiac massage and intracardiac puncture, and one to external cardiac massage alone. The findings suggest that persistent identification of serum CPK-MB, although specific for myocardial necrosis, cannot be regarded as diagnostic of myocardial infarction. The implications of this are important to treatment of patients after cardiopulmonary resuscitation and operative trauma to the heart.

Aged↗