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Biomedical subjects

B Porstmann

Publications and source records attributed to B Porstmann.

At least 19 recordsLinked to original sources
PubMed1991

[Tetramethylbenzidine--a chromogenic substrate for peroxidase in enzyme immunoassay].

3,3' 5,5'-tetramethylbenzidine (TMB) is a high sensitive chromogenic substrate for horseradish-peroxidase as a marker enzyme. In an enzyme immunoassay (EIA) for alpha-1-fetoprotein and in an rapid EIA for myoglobin it reveals higher sensitivity compared to o-phenylenediamine, the increase depends on reaction time. The optimal peroxide concentration depends on reaction time of enzyme chosen in different assays. TMB used for histochemistry is also suitable for EIA if hydrochloric acid is used as stopping reagent. TMB lacks in mutagenic properties and it should preferred for peroxidase rather than all other chromogenic substrates applied up to now.

Benzidines↗
PubMed1991

[Modified bedside diagnosis in patients at risk for aortocoronary venous bypass surgery].

Early detection of perioperative complications during cardiosurgical operations is of differential diagnostic and differential therapeutic importance. Various risk groups of aortocoronary venous bypass operations have been analysed under different aspects: age, (not significant), implemented bypass rate (aneurysm resection 1.75/p less than 0.01 compared with 2.65-2.9), death rate (= greater than 21 days) 4 to 6.3% (including patients with "bad ventricle", p less than 0.05), and the proportion of clinically relevant complications of 19 to 40% (aneurysm resection 40%/p less than 0.001). Monitoring the marker proteins is an appropriate method of judging the perioperative risk of perioperative myocardial damage in preoperatively defined high-risk patients (approximately 25% modified according to centre conditions). Patients who died always had early pathologic dynamics of marker proteins. Patients with perioperative risks (aneurysm resection and ejection fraction global less than = 30%), left main artery stenosis and unstable angina pectoris symptoms) were found to have pathologic dynamics of marker proteins to a significantly varying extent (compared to a test group). This modified approach of bedside diagnostics of risk patients confirms the preoperative selection of risk patients and forms the economically viable future basis for an individualized perioperative course control.

Alanine Transaminase↗
PubMed1990

[Therapy of perioperative myocardial damage in aortocoronary venous bypass surgery].

The perioperative lesion of the myocardium in heart-lung machine operation can on principle not be prevented despite complex measures of the protection of the myocardium and the individual monitoring of the patients, this particularly by including patients with high risk of ischaemia of the myocardium (instable angina pectoris, stenosis of the trunc and greatly restricted left-ventricular function, respectively) in former years. In a proved perioperative lesion of the myocardium the limitation of the myocardial lesion stands in the centre of intensive-medical measures with vasodilators and positive inotropic substances.

Cardiac Output, Low↗
PubMed1990

[Perioperative complications in at-risk patients undergoing heart valve surgery].

The success of operations of the replacement of heart valves is disturbed by perioperative complications and early lethality. A valuation of the perioperative risk individually of patients with operations of the replacement of heart valves according to defined subgroups is controlled by the perioperative course. In order to achieve the registration of patients with perioperative lesion of the myocardium and/or low output syndrome, the bedside performance of a marker protein monitoring consisting of enzymes/isoenzymes (CK, CK-MB, ALAT) and the muscle protein myoglobin, respectively, is necessary. In 38% of the patients with operation of the replacement of heart valves the preoperative risk constellation was objectified early-postoperatively with the proof of complication and thus the strategy of the preoperative individual valuation of the risk confirmed. Altogether patients with replacement of the aortic valve showed the smallest rate of perioperative complications in comparison to patients with replacement of the mitral valve (re-operation in replacement of the mitral valve, double valve replacement, replacement of the mitral valve with restricted left-ventricular function).

Bioprosthesis↗
PubMed1990

[Localization and type of acute myocardial infarct in relation to myocardial infarct size--patients with acute re-infarct].

A differentiated estimation of the acute re-infarction is individually necessary for the estimation of risk and prognosis. Thereby the methodical approach is of particular importance, since the further restriction of the remaining function of the myocardium in re-infarction is of fundamental significance. A monitoring for the establishment of CKmax as well as the measuring of the ejection fraction globally (EFg) allow a semiquantitative determination of the size of the myocardial infarction. This forms the basis for the evidence of smaller acute Q-wave re-infarctions and also of smaller acute re-infarctions of the posterior wall localization. The increase of the risk in non-Q-wave infarction (mean risk) and Q-wave infarction (high risk) in re-infarction could be confirmed by the ejection fraction globally. Thus significant differences of the surviving persons after acute re-infarction in comparisons to the primary infarction were elaborated.

Cardiac Output↗
PubMed1990

[Site and type of acute myocardial infarct in relation to myocardial infarct size--dynamics of global ejection fraction in acute myocardial infarct].

By the ejection fraction global (EFg) statements concerning the remaining function of the myocardium in acute myocardial infarction and thus individually concerning the prognosis (classification of risk groups) become possible. For the valuation of the dynamics of the EFg in a period up to 6 months after an acute myocardial infarction the EFg was multifariously controlled. Only patients with first myocardial infarction in localization on the anterior wall and Q-wave showed a significant dynamics of the EFg between the measurements acute and third week as well as acute and 6th month (absolutely 5.2%). --In re-infarction/Q-wave this could be confirmed also for the localization of the posterior wall in the period acute till third week. For the localization on anterior and posterior wall a dynamics of the EFg could also be calculated for the period acute and 6th month. Thereby the absolute increase of the EFg was between 4.0 and 4.6%. The dynamics of the EFg in the region of the anterior wall was 5.2% for the first infarction and only 4% for the reinfarction. Thus it is below the dynamics of the EFg in an effective thrombolytic therapy.

Angina Pectoris↗
PubMed1990

Production and characterization of monoclonal antibodies against human Cu/Zn superoxide dismutase and the establishment of a super-rapid enzyme-linked immunosorbent assay (SURALISA).

Murine monoclonal IgG1 antibodies directed against four different epitopes of human Cu/Zn superoxide dismutase (SOD) were produced by immunization with recombinant Cu/Zn SOD. The antibodies reacted well with the recombinant protein and Cu/Zn SOD purified from human erythrocytes, with binding constants ranging from 8.8 X 10(9) to 2.2 X 10(10) l/mol. When mixed, these antibodies completely prevented the binding of rabbit and sheep polyclonal antibodies raised against erythrocyte Cu/Zn SOD. Whereas one antibody was directed against a common homology region of bovine and human Cu/Zn SOD, all the other antibodies reacted exclusively or preferentially with human Cu/Zn SOD. Only one epitope on the human Cu/Zn SOD molecule was accessible at two different sites as demonstrated in a homologous two-site assay with one and the same antibody used as both capture and indicator antibody. In the indirect two-site assay with unlabelled monoclonal antibodies, and additive effect with a steeper dose-response curve was obtained by mixing antibodies against different epitopes. A super-rapid one-step two-site enzyme immunoassay (overall duration 20 min) was established with antibodies against two different epitopes. Its detection limit was 0.5 micrograms SOD/l.

Antibodies, Monoclonal↗
PubMed1990

[Enzyme immunoassays for the quantification of human gamma-gamma-enolase (NSE)].

A direct two-site binding assay on the basis of antibodies from sheep for the quantification of human gamma-gamma enolase is described. The antibody was produced by immunization with human NSE coupled to horse spleen ferritin. The assay shows two feature: a decreased reactivity with NSE from rat and NSE from human serum in spite of 100% recovery of purified human brain NSE. The sheep antibody seems to react with epitopes less accessible on the rat NSE and on the NSE of human serum. The assay is characterized by gamma-gamma enolase specificity, a high sensitivity (2 pg) and a precision of CV = 3-7%.

Animals↗
PubMed1989

Measurement of lysozyme in human body fluids: comparison of various enzyme immunoassay techniques and their diagnostic application.

Three variants of the immunoenzymometric assay of human lysozyme with HRP-labeled antibodies were compared. The highest sensitivity (with a detection limit of 0.2 micrograms lysozyme/L) was achieved by a one-step assay lasting 2 h. Between-batch precision for the techniques was 6-11%. Lysozyme reference values were determined in serum, cerebrospinal fluid and urine. In serum they are age-dependent and in urine sex-dependent when related to creatinine excretion. Serum lysozyme is increased in only 57% of the patients with active rheumatoid arthritis and is also unreliable for indicating remission. In Crohn's disease the serum lysozyme reflects activity better, but it does not exceed the diagnostic value of alpha-1-acidic glycoprotein (orosomucoid). The lysozyme quantification in cerebrospinal fluid is useful in distinguishing between viral or bacterial meningitis.

Acute Disease↗
PubMed1988

A rapid and sensitive enzyme immunoassay for Cu/Zn superoxide dismutase with polyclonal and monoclonal antibodies.

An enzyme immunoassay for the quantification of human Cu/Zn SOD in serum, urine and erythrocytes was developed applying monoclonal and polyclonal antibodies. The one-step assay is completed within 30 min and enables the detection of 0.3 microgram Cu/Zn SOD per litre. A Cu/Zn SOD concentration of 46 +/- 21.5 micrograms/l and of 1 +/- 0.6 micrograms/mmol creatinine was determined in the serum and the urine, respectively, of healthy individuals. A content of 15 +/- 1.7 ng Cu/Zn SOD was found in 10(6) erythrocytes. Patients with Down's syndrome exhibited a 3.8-fold, a 2-fold and a 1.6-fold higher concentration of Cu/Zn SOD in their serum, urine and erythrocytes.

Antibodies↗
PubMed1988

Diuresis-dependent excretions of low-molecular mass proteins in urine: beta 2-microglobulin, lysozyme, and ribonuclease.

An investigation was carried out into how the low-molecular mass proteins beta 2-microglobulin, lysozyme, and ribonuclease were excreted over 8 h after high fluid intake (22 ml/kg of body weight in 15 min). With increasing urine flow rate the amount of lysozyme excreted per hour or per millimole creatinine increased more markedly than that of beta 2-microglobulin while at the same time the excretion rate of ribonuclease decreased. The effect of urinary flow upon the excretion rates of the various low-molecular mass proteins has to be considered as a preanalytical factor when these proteins are used as indicators of tubular dysfunction.

Adult↗
PubMed1987

Coupling of different isoenzymes of horseradish peroxidase influences the sensitivity of enzyme immunoassay.

Labelling of IgG with various HRP isoenzymes purified by preparative isoelectric focussing influences the yield and the specific activity of the conjugates. Alkaline isoenzymes were preferably coupled by glutaraldehyde whereas application of the periodate method additionally formed relatively large quantities of conjugates with acidic isoenzymes of a high purity number, but a low specific activity. In an enzyme immunoassay for alpha fetoprotein the detection limit can be varied by a factor of 6 and even by a factor of 20 by use of the conjugates with different isoenzymes coupled by the glutaraldehyde method and the periodate method, respectively. In order to achieve enzyme immunoassays of the highest sensitivity, antibodies should be coupled to horseradish peroxidase after removing acidic isoenzymes from the enzyme preparations.

Antibody Specificity↗