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Biomedical subjects

W Gerhardt

Publications and source records attributed to W Gerhardt.

At least 55 records · Page 3Linked to original sources
PubMed1985

Specific immunoassay of alpha-amylase isoenzymes in human serum.

A monoclonal antibody (66C7) was prepared that specifically binds human salivary amylase (EC 3.2.1.1); it cross reacts with human pancreatic amylase by less than 1%. Two procedures are described for determination of isoamylases in human serum with this antibody: an enzyme immunoassay for determining amylase of salivary origin, and a routine method in which this amylase is immunoprecipitated and the remaining (pancreatic) amylase activity is assayed. Results by the two methods correlate well.

Antibodies, Monoclonal↗
PubMed1983

Multicentre investigation of myocardial protection with cold cardioplegia.

In order to analyze factors of importance for the efficiency of myocardial protection during open-heart surgery, a study was made of 144 patients undergoing isolated aortic valve replacement with various cardioplegic techniques. The cardioplegia was of Bretschneider type in 54 cases, St Thomas in 31 and Ringer-potassium type in 11 cases. Single or multi-dose blood cardioplegia was used in 11 cases and continuous blood cardioplegia in 30 cases. Local cardiac hypothermia was additionally employed in all patients. The efficiency of myocardial protection was assessed mainly from the incidence of postoperative conduction disturbances, myocardial enzyme release and need for inotropic support. All patients survived the operation. In 20% surgery was followed by transient or persistent disturbance of conduction, in 9% by abnormally increased CK-MB release and in 5% by requirement for inotropic support. Preoperative risk factors such as high age or severe left ventricular (LV) hypertrophy or dysfunction had little influence on the results. Patients in whom aortic stenosis (AS) was dominant in the complex with aortic insufficiency (AS + AI) showed 20-hour postoperative CK-MB enzyme activity twice as high as those with pure aortic insufficiency. The most important factors in myocardial protection were the duration of aortic occlusion and the myocardial temperature during cardioplegia. When the aortic occlusion lasted more than 80 min there was a 32% incidence of conduction disturbances and 20-hour CK-MB activity thrice as high as after shorter occlusion. Patients with mean myocardial temperature below 18 degrees C during cardioplegia invariably had low enzyme activities, which indicated good myocardial protection. The best overall results were obtained in patients operated on during hypothermia at 25-27 degrees C, with single or multi-dose blood cardioplegia and with efficient local cooling of the heart.

Adult↗
PubMed1983

Serum LD-1 activity in suspected acute myocardial infarction.

We have studied the diagnostic value of measuring lactate dehydrogenase (LD) isoenzyme 1 in serum of 331 cases of suspected acute myocardial infarction (AMI). At a discriminatory level of 200 U/L (Scandinavian Committee on Enzymes, recommended method for the determination of LD) LD 1 verified the diagnosis in 96% of the AMI cases and excluded it in 96% of the not-AMI cases when samples were drawn 24-72 h after onset of pain. The correlation between 24-h S-LD-1 and 16-h S-CK B activities was 0.94 in the AMI cases. We found that quantitation of serum LD-1 is diagnostically more reliable than the serum LD-1/LD ratio.

Acute Disease↗
PubMed1982

Plasma carboxypeptidase activity and intolerance to acetylsalicylic acid unimpaired CP-N activity in ASA-intolerant individuals.

Carboxypeptidase N (EC 3.4.17.3, arginine carboxypeptidase, kininase, anaphylatoxin inactivator) activity was determined in human sera with the method of Erdös by differential spectrometry at 254 nm and 37 degrees C, using hippuryl-L-argininic acid (HLAa) as a substrate. Day-to-day imprecision (CV) of the assay was 6.5%. The reference value, as determined in 15 healthy blood donors, was 3,082 +/- 432 IU/1. The mean value in a pool of sera from 12 healthy pregnant women, 4,500 +/- 294 IU/1, was higher in accordance with earlier findings by Erdös et al. Sera from 53 patients with chronic asthma or chronic urticaria, without known acetylsalicylic acid (ASA) intolerance, gave the mean value of 3,583 +/- 768 IU/1, and those from 17 patients with chronic asthma or chronic urticaria and ASA intolerance 3,379 +/- 575 IU/1. Thus, the carboxypeptidase-N activity in the blood of ASA-intolerant asthmatics and urticaria patients was unimpaired. A 16-year-old boy with asthma and without ASA intolerance showed an unusually low value of 2,056 IU/1.

Aspirin↗
PubMed1982

Creatine kinase and creatine kinase B-subunit activity in serum in cases of suspected myocardial infarction.

We evaluated a diagnostic strategy by studying 481 patients suspected of having had an acute myocardial infarction; the prevalence of infarction by independent criteria was 0.43. This strategy is based on the sequential application of: (a) clinical criteria; (b) total creatine kinase determinations in two serum samples drawn within 10 to 20 h of the onset of acute symptoms; and (c) creatine kinase B-subunit (S-CK B) determinations after immunoinhibition with antibodies to creatine kinase M-subunit in the reaction medium in all samples found to have increased total creatine kinase activity. Discrimination limits of 150 U/L total creatine kinase for women and 200 U/L for men gave a diagnostic sensitivity of 0.99. Activities less than these limits in samples identified 68% of the 274 non-infarct cases (posterior probability of a negative result of 0.99) within 20 h. Subsequent determination of S-CK B in 292 patients who were positive by the discrimination limits for total creatine kinase verified myocardial infarction in 99% of 207 cases for which S-CK B exceeded the discrimination limit of 12 U/L. The strategy excluded 98% of all non-infarct cases at a posterior probability of 0.99.

Alanine Transaminase↗
PubMed1982

[Chronic hemodialysis from the perspective of the dialysis team].

By means of a questionnaire the authors checked the views of dialysis teams on ethical and psycho-emotional questions, on on the adaptation of dialysis patients and on dialysis work itself. The results show that psycho-emotional considerations are of considerable importance in the contact with patients over long periods. The staff think about them but are often not able to arrive at a clear opinion. This indicates that psychological training of the staff is necessary in oder to facilitate and encourage the formation of clear points of view.

Adult↗
PubMed1980

Serum creatine kinase B subunit activity in diagnosis of acute myocardial infarction.

The value of serum creatine kinase B subunit activity (CK B) in the diagnosis of acute myocardial infarction was studied in 238 consecutive cases. All were admitted to a coronary care unit because of suspected acute myocardial infarction. Serum CK B activity was determined by an immunoinhibition procedure, using a CK M subunit inhibiting antibody (anti-M). For the evaluation of serum CK B, patients were classified into acute myocardial infarction and non-acute myocardial infarction groups. This classification was based on electrocardiographic findings, on quantitative determinations of serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and total serum creatine kinase (CK) activities, and on qualitative electrophoretic determinations of serum CK and serum lactate dehydrogenase (LD) isoenzymes. The prevalence of acute myocardial infarction in the patient material was 0.47. Serum CK B subunit activity was found to be a highly selective indicator of acute myocardial infarction with a predictive value of a positive test result of 0.97 and a predictive value of a negative test result of 0.99. The serum CK B activity increased above the acute myocardial infarction discrimination limit within 12 hours from onset of symptoms. Two non-acute myocardial infarction patients, who were resuscitated after cardiac arrest, had increased serum CK B values caused by the transient presence of CK isoenzyme BB in serum.

Aged↗
PubMed1980

Influence of analytical quality on the diagnostic power of a single S-CK B test in patients with suspected acute myocardial infarction.

We have compared tow theoretical methods for assessing the effects of changing analytical quality of a clinical chemical test. The test considered was S-creatine kinase B subunit activity, used as the only diagnostic criterion for acute myocardial infarction. The two methods applied were based on (i) graphical analysis, and (ii) computer simulation. The results comprise the effects of changing analytical imprecision and bias on the weighted sum of misclassified cases on basis of the test results. The two methods yield comparable results at high analytical imprecision, but due to differences in assumptions about the error distribution of test results the difference increases with increased analytical imprecision. The graphical analysis is easily performed but is restricted in possible applications. The computer simulation is not a generally available methodology, but allows for mixing of different types of statistical distributions, which is not the case in conventional variance analysis.

Chemistry Techniques, Analytical↗