Biomedical subjects

J Büttner

Publications and source records attributed to J Büttner.

At least 19 recordsLinked to original sources

PubMed1992

The origin of clinical laboratories.

Clinical laboratories are a main attribute of clinical chemistry. Their historical development is therefore of great interest in the history of clinical chemistry. The results of a study are given which was undertaken to trace the establishment of clinical laboratories in central Europe, mainly in France, England and in the German-speaking countries. Presuppositions for the creation of these laboratories were: (i) The idea that the results of laboratory examinations can be used as "chemical signs" in medical diagnosis, and (ii) a new concept of disease which was the result of the "birth of the clinic" at the end of the 18th century. The study shows that the development of clinical laboratories began 200 years ago. Up to the end of the 19th century, three development phases can be distinguished: an early phase from 1790 to 1840, a phase of institutionalization from 1840 to 1855, and a phase of extension between 1855 and 1890. To characterize these three phases, the foundation of the laboratories, the layout of the laboratory rooms, their equipment and instrumentation, and the usual staff are described with the aid of typical examples.

Chemistry, Clinical↗

PubMed1992

[The effect of adding clonidine to mepivacaine. Axillary brachial plexus blockade].

Clonidine (Cl) added to local anaesthetics (LA) prolongs the duration of both anaesthesia and analgesia after peripheral nerve blocks. In this study, we investigated the dose-dependent effect of Cl added to mepivacaine (M) on clinical efficacy, onset, and regression time of brachial plexus block. METHODS. Ninety patients were randomly assigned to one of three groups. Every patient received 46 ml of a mixture containing 400 mg M (pH adjusted with NaHCO3 to 7.25) and either 0.9% NaCl (group A), 0.12 mg Cl (group B), or 0.24 mg Cl (group C). The axillary block was performed using the catheter technique. In a double-blind fashion, the onset of sensory and motor blockade was tested every 5 min for 30 min. Duration of anaesthesia, analgesia, and motor blockade (time between injection and return of sensation, onset of pain, or ability to move, respectively) was assessed using a questionnaire. M plasma levels were measured by HPLC in 10 patients from each group for up to 120 min. Blood pressure (BP), heart rate (HR), and respiratory rate (RR) were measured for up to 120 min. Sedation was assessed using a verbal rating scale. RESULTS. There was no difference in the onset of blockade. There was dose-dependent prolongation of the duration of anaesthesia, analgesia, and motor blockade with significant differences between groups C and A regarding all three parameters, between groups C and B regarding duration of anaesthesia, and between groups B and A regarding duration of analgesia. There was no significant difference in M plasma levels. Although there was only a slight but significant decrease in mean BP values in groups B+C and no difference in HR and RR, 2 patients (1 group B, 1 group C) had marked decreases in BP and HR (less than 70 mmHg systolic resp. less than 50/min) after 120 and 210 min. Sedation occurred in most patients receiving Cl. CONCLUSIONS. Addition of Cl to LA produces a dose-dependent prolongation of anaesthesia, analgesia, and motor blockade. Neither the onset time nor the number of patients with adequate surgical anaesthesia was influenced by Cl. Considering the M plasma levels, it is unlikely that the prolongation of the block is caused by local vasoconstriction, which is proposed to be the mechanism of action of epinephrine. The mean differences in haemodynamic parameters were not of clinical relevance, but the two dramatic drops in BP and HR, probably caused by Cl, were significant.

Adult↗

PubMed1991

[Laboratory medicine in the area of interest between medicine and science].

The scientific disciplines of laboratory medicine are analyzed from the point of view of history and the philosophy of science. The results of this study are the following: 1. Laboratory medicine is the name of a group of subjects which exist in an interdisciplinary area between medicine and science. 2. Historical development shows that these subjects arose in the 19th century when medicine adopted the "natural scientific method" and became "scientific medicine". 3. Clinical chemistry, as one example of these subjects, is analyzed in detail to understand the thinking process and the scientific method. This subject is, on the one hand, a "theoretical discipline" (like all of the natural sciences) but, on the other hand, it is a typical "practical scientific discipline" (which like clinical medicine is aimed at certain decisions and actions). 4. The disciplines of laboratory medicine have developed typical "professions" mainly because of their application in clinical practice and their commitment to patient care.

Chemistry, Analytic↗

PubMed1991

Renal abscess in childhood: diagnostic and therapeutic progress.

During the past decade new techniques such as computed tomography (CT) and ultrasonography have been reported to have changed the diagnostic investigation and treatment of renal abscess in adults. To evaluate whether similar changes have taken place in the pediatric age group, a retrospective study of all patients seen between 1979 and 1989 was performed. Seven patients, 0.8 to 14 (mean, 9) years old, with renal abscesses in eight kidneys were identified. Ultrasound and computed tomography proved to be the most valuable diagnostic tools, revealing the diagnosis by showing a hypoechoic or hypodense mass. All patients had an initial trial of intensive antibiotic treatment, which led to resolution of the abscesses in two of the eight kidneys. In all other cases the abscesses were additionally drained, which was done surgically in two and by ultrasonography- or CT-guided percutaneous drainage in four patients. Abscess cultures grew Staphylococcus aureus (three), Escherichia coli (one) and Salmonella Group B (one) and were sterile in one case. Drainage was unsuccessful in only one patient, who subsequently underwent nephrectomy for uncontrolled infection of a diffusely damaged kidney. We conclude that the diagnosis of renal abscesses is greatly facilitated by ultrasonography and CT and that most patients can be cured without operation by antibiotics and, if necessary, by additional percutaneous drainage.

Abscess↗

PubMed1991

Clinical chemistry: a professional field for physicians and natural scientists in Europe.

1. Clinical chemistry is definitely an interdisciplinary subject between natural science and medicine. The major part of clinical chemistry is natural science and therefore theoretical science. To a lesser extent, however, clinical chemistry is practical science or "action science" which is aimed at a certain action. 2. The question "Is clinical chemistry a professional field for physicians, for scientists or for both?" can be answered with the statement: It follows from its historical development and its characteristic theory and practice, and is de facto true throughout the world, that clinical chemistry is a professional field for physicians and natural scientists. 3. The broad scope of the technical field and the challenges to be expected in future within the framework of the European Community will require the recruiting aspiring clinical chemists both from medicine and from the natural sciences. 4. Qualified postgraduate training is more important than the nature of the initial study course. 5. Apart from providing special knowledge and particular abilities, postgraduate training must make the younger generation familiar with the ways of thought of the physician and of the natural scientist. 6. Successful work as a clinical chemist requires "extra-functional" qualifications, such as the ability to conduct dialogue and teamwork with the clinician. 7. The national differences which exist in the definition of the professional pattern "clinical chemist" are a hindrance to the future development of the discipline in the European Community. The starting point for recognition of the profession must be an agreed definition among the professionals of the countries of the European Community of the professional field of the clinical chemist.

Chemistry, Clinical↗

PubMed1991

Reference methods as a basis for accurate measuring systems.

Reference methods, as part of a reference system, are essential for improving the accuracy of routine methods. They can help to establish worldwide compatibility of clinical chemical measurements and they provide an objective basis for quality control measures. The subject of analytical errors is treated in detail, then the concept of reference methods is developed. This review emphasizes the fundamental metrological aspects of reference methods and reference measurement technology. An overview is given of the most important analytical principles used for reference methods in clinical chemistry. The particular problems of reference methods for the determination of the catalytic activity concentration of enzymes are outside the scope of this review.

Chemistry, Clinical↗

PubMed1991

Philosophy of measurement by means of immunoassays.

Starting from the explanation of the terms "comparison" and "quantification" a concept of a metrologically correct measuring system is derived. The paper discusses how this concept can be applied to immunoassays. The investigation led to the following conclusions: 1. Immunoassays are not principally either comparative tests or quantitative tests. Whether or not a correct measuring system can be construed for an immunoassay test depends on the intended use and the conditions in the specific individual case. 2. If certain requirements, which are discussed in detail, are fulfilled, immunoassays can be used for measuring the substance composition of biological materials. Critical points are the unambiguous definition of the "chemical entity" of the analyte to be determined (especially of macromolecules), the calibration of the measuring system by means of standards, and the problem of matrix effects.

Immunoassay↗

PubMed1991

[Alkalinization of mepivacaine for axillary plexus anesthesia using a catheter].

One disadvantage of perivascular axillary block using a catheter technique is delayed temporal development of the blockade. Some clinical studies have concluded that pH-adjusted solutions of local anesthetics produce a more rapid onset of blockade. Alkalinization of mepivacaine for brachial block produced conflicting results. In the present study, we attempted to define the effect of alkalinization of mepivacaine 1% on clinical efficacy, onset, and regression in patients undergoing upper extremity surgery with axillary block using the catheter technique. METHODS. Sixty consecutive adult patients (ASA I-II) scheduled for upper extremity surgery under axillary block, were randomly assigned to one of two groups. In a double-blind fashion, 30 patients received 40 ml 1% mepivacaine, the pH of which had been raised to 7.25 by adding 4 ml 8.4% NaHCO3, and 30 received 40 ml commercially prepared 1% mepivacaine hydrochloride solution containing 4 ml 0.9% NaCl (pH 6.0). All patients received axillary block using the catheter technique. After placement of the block, a blinded observer tested sensory and motor blockade after 2 min, 5 min and then every 5 min for 30 min in each of the terminal nerves of the brachial plexus. Sensory blockade was determined by pinprick and graded in accordance with the scale proposed by Hollmèn: 0: Normal sensation of pinprick. 1: pinprick felt as sharp-pointed but weaker compared with the same area in the other upper extremity. 2: Pinprick recognized as touch with a blunt object. 3: No perception of touch. The gradation of motor blockade was 0: normal muscular function; 1: slight depression in muscular function compared with preanesthetic strength; 2: very weak action persisting in muscles; and 3: complete block. The results for each group were compared at every time interval. Duration of blockade was compared by evaluating the rate of regression within the first 2 h after placement of the block in each group. Mepivacaine plasma levels were measured by HPLC in 10 patients of each group prior to injection and 5, 10, 15, 20, 30, 60, and 120 min thereafter. Statistical comparison was made using the chi 2 and t tests. Differences were considered statistically significant when P-values were less than 0.05. RESULTS. The bicarbonate and saline groups were similar with respect to age, height, weight, and sex distribution. Significantly more patients in the bicarbonate group showed onset of motor blockade (grade 1) after 2 min with respect in the axillary, musculocutaneous, radial, and median nerves as well as onset of sensory blockade in the same nerves with a significant difference in blockade of the radial nerve. (ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗

PubMed1991

Laboratory findings: structure, validity and significance for medical cognitive processes.

Modern medicine employs laboratory findings to a great extent in medical cognitive and decision processes. As supposedly "hard" data, the value of such findings is frequently incorrectly assessed. So far, no comprehensive general theory of laboratory findings has been available, although various subproblems have been dealt with. Firstly, the structure of a laboratory finding will be investigated in detail, proceeding from an analysis of the scientific language used for laboratory findings. The part played by laboratory findings in medical cognitive processes in making a diagnosis or prognosis will then be shown. Finally, attempts at characterizing the validity of a laboratory finding with the aid of statistical methods and information theory, as well as appropriate steps for checking the validity will be discussed.

Clinical Laboratory Techniques↗

PubMed1990

Prehospital thrombolysis in acute myocardial infarction.

The benefit and risk of prehospital thrombolysis for acute myocardial infarction (AMI) were evaluated in a double-blind randomized trial. Patients presenting less than 4 hours after symptom onset received 2 million units of urokinase as an intravenous bolus either before (group A, n = 40) or after (group B, n = 38) hospital admission. The mean time interval from onset of symptoms to thrombolytic therapy was 85 +/- 51 minutes in group A and 137 +/- 50 minutes in group B (p less than 0.0005). In 91% of the patients, thrombolytic therapy was administered less than 3 hours after symptom onset. Complication rates during the pre- and in-hospital period were low and did not differ between groups. Three patients died (1 in group A, 2 in group B) from reinfarction 7 to 14 days after admission. Left-sided cardiac catheterization before discharge revealed a patency rate in the infarct-related artery of 61% in group A and 67% in group B (difference not significant). Global left ventricular function and regional wall motion at the infarct site did not differ significantly between group A and B (ejection fraction 51 +/- 10%, n = 28 vs 53 +/- 14%, n = 28; wall motion -2.3 +/- 1.3 vs -2.2 +/- 1.1 standard deviation, respectively). Also, peak creatine kinase did not differ significantly (838 +/- 634 U/liter in group A vs 924 +/- 595 U/liter in group B). Prehospital thrombolysis using a bolus injection of urokinase has a low risk when performed by a trained physician with a mobile care unit. The saving of 45 minutes in the early stage of an acute infarction through prehospital thrombolysis did not appear to be important for salvage of myocardial function.

Ambulances↗

PubMed1990

[The thrombolysis treatment of acute myocardial infarct at the site of the emergency. A randomized double-blind study].

Two million units of urokinase were administered intravenously as a bolus, either before (group I, n = 40) or after hospital admission (group II, n = 38), to 66 men and 12 women (mean age 55 +/- 8 years) with typical symptoms of acute myocardial infarction of less than 4 hours' duration. Time elapsed between onset of symptoms and urokinase administration averaged 85 +/- 51 min for group I and 137 +/- 50 min for group II (P less than 0.005). The complication rate was low, both during the pre-hospital and the hospital phases, without any significant differences between the two groups. The rate of open infarct vessels (by angiography before discharge from hospital) was 61% for group I and 67% for group II (no significant difference). Global left ventricular function, regional wall motion in the infarct area and maximal creatinekinase values did not significantly differ between the two groups (ejection fraction 51 +/- 10% and 53 +/- 14%, respectively; creatinekinase 838 +/- 634 U/l and 924 +/- 595 U/l, respectively). The data indicate that thrombolytic pre-hospital treatment carried a low risk. The gain of 45 min, however, seems to be of secondary importance in any significant diminution of the acute infarction size.

Coronary Angiography↗

PubMed1990

[Does a cone-shaped cannula needle offer an advantage in spinal anesthesia?].

The so-called atraumatic spinal cannula of Sprotte is a modification of the Whitacre spinal needle. It consists of a conical tip with a lateral opening. This cannula (24 G) is said to cause a very low incidence of postspinal headache. In a prospective study, it was compared to a 25 G cannula with a Quincke tip. PATIENTS AND METHOD. The study was carried out on 500 patients who received spinal anesthesia for operations on the lower extremities. The cannulas were randomly assigned to the patients. Puncture characteristics and number of incomplete blocks were evaluated. Postoperatively patients were interviewed on days 1, 3, 5, and 7. Neither the subjects nor the investigator were aware of the type of cannula used. RESULTS. There were no differences with regard to age and sex; 80% of the patients ranged between 15 and 55 years, with a homogeneous spread. Performance of the block was superior with the Sprotte cannula and the incidence of incomplete blocks was lower (1.6% vs 7.8%, P = 0.0011). There was no significant difference with regard to postspinal headache (8.2% vs 7.8%). CONCLUSIONS. The atraumatic cannula had better puncture characteristics, but there was no statistically significant difference with regard to postspinal headaches.

Adolescent↗

PubMed1990

[Problems of intubation using the flexible LF-1 fiberoptic bronchoscope. Development of an intubation aid].

Fiberoptic endotracheal intubation with an endoscope (external diameter 4 mm) especially designed for anesthesiologists proved to be safe providing small-diameter tubes were used. The use of large-diameter tubes (I.D. 7.5-8.5 (mm)) involves a risk of the tip of the tube clinging to the arytenoid cartilages preventing any further advancement. To avoid this complication another special tube has been constructed, which fills the space between the endotracheal tube and the bronchoscope and centers the bronchoscope within the endotracheal tube. When this new tube was used there were no problems either in passing the bronchoscope through this "inner" tube or in withdrawing the inner tube after successful intubation. With the new device it was even possible to pass tubes with wider lumen into the trachea over the fiberscope with minimal difficulty and trauma.

Bronchoscopes↗

PubMed1989

[Historical prerequisites for the development of clinical chemistry].

Clinical Chemistry emerged as an independent discipline about 1840. Important roles in this development were played by "the revolution of chemistry" (Lavoisier), the "birth of clinic", the "natural historical method in clinical medicine" (Schönlein) and reception of the scientific method in medicine.

Austria↗

PubMed1989

A candidate reference method for the determination of magnesium in serum.

A candidate reference method for the determination of magnesium in serum (analytical range 0.5 to 2.0 mmol/l) by flame atomic absorption spectrometry was commissioned. The relative standard deviation of the 4 replicates of each value ranged from 0.18 to 1.07%, and the standard error of the mean ranged from 0.63 to 8.34 mumol/l. In the analysis of 3 different standard solutions (prepared by weighing the analyte), which was performed in each of three different experiments the values recorded by the candidate reference method deviated by -0.15, 0.44 and 0.24%, respectively. The reference method value did not differ significantly from the definitive value. As the method seems to be as reliable as comparable reference methods for the determination of sodium, potassium or calcium, tests of transferability should now be undertaken.

Animals↗

PubMed1989

Methods for pH determination in human erythrocytes.

The methods described in the literature for pH determination in human erythrocytes, i.e. the direct potentiometric measurement of haemolysed erythrocytes and the 5,5-dimethyl-2,4-oxazolidinedione (DMO) method, were examined and compared. In spite of careful optimization of the experimental technique, a statistically significant difference of a few hundredths of a pH unit remained between the results of the two methods. The calculation of the cellular water space of the erythrocytes is suggested as a possible reason for this difference; in the DMO method this leads to uncertainty in the determination of the DMO concentration and therefore in the derived intracellular pH values. For clinical use, the direct pH measurement of haemolysed erythrocytes, using the technique described here, is recommended.

Dimethadione↗

PubMed1989

[Continuous axillary catheter plexus anesthesia--a method of postoperative analgesia and sympathetic nerve block following hand surgery].

During a period of one year (March 1985 to March 1986) 52 axillary brachial plexus catheters were left in place for two to twelve days. The main indications were postoperative analgesia and sympatholysis after microvascular surgery of the hand. With the continuous infusion of 0.25% or 0.375% bupivacaine, 6-8 ml/h a sufficient effect was seen. There was no evidence of accumulation of the administered drug after a prolonged period of infusion. A steady state of serum levels built up in the range between 0.5 to 1.5 micrograms/ml. There were no toxic side effects by the local anaesthetic agent. In one case an infection of the axillary region developed, which disappeared after removal of the catheter without any consequences. In summary the continuous axillary brachial plexus block is an acceptable method for intra and postoperative analgesia and sympatholysis in microvascular surgery of the hand.

Autonomic Nerve Block↗

PubMed1988

[Axillary blockade of the brachial plexus. A prospective evaluation of 1133 cases of plexus catheter anesthesia].

UNLABELLED: The results of 1133 axillary catheter brachial blocks are reported. Effectiveness and side-effects were monitored in a prospective manner over a period of 1 year. METHOD: The puncture was performed with an 18-gauge plastic cannula fitted with a solid steel stylet. The stylet has a 45 degrees, short bevel with rounded edges. When puncturing the axillary neurovascular sheath, no attempt was made to elicit paresthesias with the needle. A distinct "click" and very easy advancement of the plastic cannula were signs of being well inside the neurovascular sheath. To confirm the correct positioning, 0.5-3 ml refrigerated saline solution were injected. If no paresthesias could be produced, a new puncture was performed using a nerve stimulator. The plastic cannula was fixed to the skin. For long-lasting operations or if postoperative analgesia or sympatholysis was required, a more flexible catheter was introduced through the plastic cannula. As an initial dose 40 ml 1% mepivacaine was injected via the cannula. If there was an insufficient block after 20 min, another 20 ml 1% mepivacaine was given. For long-lasting operations, 40 ml 1% mepivacaine was injected every 2 h. RESULTS: Surgery was completed in 72% of patients; 24% required some form of supplementation including 17.2% of patients who received a "top-up" after 20 min (Table 1). In 3.8% of cases the technique was considered to be a complete failure, meaning that patients needed some type of general anesthesia including the use of i.v. ketamine.(ABSTRACT TRUNCATED AT 250 WORDS)

Axilla↗