Biomedical subjects
Publications and source records attributed to R Friedel.
Six weeks after operative treatment of a rupture of the long head of biceps brachii using keyhole tenodesis on the left arm in a man 69 years old a fracture of the upper arm happened. The reason seems to be the localization of keyhole osteotomy being probably to much distal.
A significant atrophy of the biceps brachii muscle without decreasing maximal force during flexion in the elbow joint was shown at least 1.5 years after surgical refixation in 6 patients with a tendon-rupture of the long head of the right biceps. A decreased myoelectrical activity was found in the caput longum region of the muscle. The decrease correlates with an increase of spectral myoelectrical power in the region of caput breve or brachioradialis muscle. In addition compensatory recruitment processes can be supposed because of changed spectral myoelectrical power in the low-frequency bands. Changes of the morphological structure of the muscle were only found in 1 patient by sonography.
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In cases of joint fractures as well as in dislocated and open fractures of the hand special standards concerning operation methods have to be set. Treatment of soft tissue damage accompanying the fracture is in no other region of the body so important. Therefore the current efforts for development of an AO-classification for fractures of the hand taking into account the soft tissue damage are of major significance. Special features of miniosteosynthesis compared to conventional osteosynthesis are the subject of this study. The use of the miniplate especially in juxtaarticular fractures of the hand due to complex injuries or replantations can overcome the disadvantages of joint-bridging K-wires. Osteosyntheses of the hand are making high technical demands on surgeons and are not at all operations for beginners.
25 patients with injuries of the hand were treated by a new external minifixator. A specific joint bridging construction makes it possible to treat severe joint fractures by ligamentotaxis. Another indication is the preoperative continuous elongation treatment in severe contractures of the fingers. The minifixator can be made dynamic and can also be used for interfragmental compression or distraction.
Within a time of ten years 144 patients with difficult injuries on their hands were operated. These were 95 replantations and 102 revascularizations. 26 patients had to be operated again because of arterial and venous thrombosis. 46% of our patients had early vascular complications already within 24 hours. The frequency of thrombosis was increasing with the accompanying soft tissue injury and therefore with the gravity of the trauma. Avulsion injuries had of course the worst prognosis. After diagnosis of vascular occlusion within the replanted finger there should be a quick surgical revision of the anastomosis. With the help of application of urokinase into the artery we could create the circulation without any new production of the anastomosis in two cases. With a subtile technique of the disposition of the anastomosis and two venous connections to one artery with the replanted fingers we could reduce the rate of thrombosis and improve the results.
Cultured ascites tumor cells and their lipid-depleted variants containing 35-40% less membrane phospholipid and cholesterol were used to study uptake and metabolism of fatty acids complexed to albumin. Uptake of stearate and oleate at 37 degrees C was considerably higher in the lipid-depleted cells, but no significant difference in the affinity constants for stearate uptake of 3.70 microM for the lipid-depleted and 2.50 microM for the control cells was observed. Similar rates of uptake of both cultures were observed at lower temperatures up to 30 degrees C. The drastic increase in stearate uptake above 30 degrees C resulted in an endothermic transition in the Arrhenius plot with an activation energy of 20.8 kJ/mol versus 6.5 kJ/mol for the control cells. Uptake of stearate and oleate of the control cells was only slightly reduced by metabolic inhibitors, which was similar to stearic acid transport in the lipid-depleted variants. However, oleate uptake was substantially decreased in these variants. Incorporated stearate was esterified to about 50% in both cultures, and oleate between 85 and 90%. Mainly triacylglycerols and phospholipids with phosphatidylcholine (41%) and phosphatidylethanolamine (35%) as major polar lipid components, and also lower acylglycerols and cholesterol were found to be labeled. Under lipid-depleted conditions, a pronounced increase in the relative proportion of oleate incorporation into triacylglycerols was determined. It is suggested that fatty acid uptake is controlled by the number of active sites of the putative transport protein, which increases upon lipid depletion as shown from the V values. This increase may result from the segregation of membrane-bound proteins into domains (Haeffner et al. (1986) Cell Mol. Biol. 32, 359-368), which are known to be formed as a consequence of lipid phase separation in the lipid-depleted cells.
60 pancreatic pseudocysts are reported. 29 cystojejunostomies, 22 cystogastrostomies, 2 cystoduodenostomies and 7 external drainages were performed. Most favourable results could be recorded by cystojejunostomy. The total operative mortality was 8.3%, after cystojejunostomie 3.4%. Most dangerous complications were haemorrhage and peritonitis. In the follow up of internal operative drainage approximately 80% excellent or satisfactory results could be observed. Pancreatic pseudocysts lasting more than 6 weeks should be submit to surgical treatment. Cystojejunostomy is the most favourable procedure. External drainage is indicated in emergency or development of complications.
Two studies with healthy volunteers were carried out to correlate safety with pharmacokinetics of the calcium antagonistic drug N-(3,3-diphenylpropyl)-(1-phenylethyl)-amine (fendiline, Sensit) after single and multiple oral doses. In the first study single doses of 200, 400, 600, 800, 1000, and 1200 mg of fendiline hydrochloride were administered to 6 subjects per dose level. 3 additional subjects per dose level received placebo. No significant objective or subjective effects were noted in the dose range studied. The pharmacokinetic analysis revealed that doses higher than 800 mg were absorbed incompletely. In the second study initially 400 mg twice daily was given to 9 subjects. 3 additional subjects received placebo. Due to subjective intolerability (trembling, dizziness) after 5 days, the dose was reduced stepwise to 2 X 200 mg and was then continued for another 19 days. The pharmacokinetic evaluation revealed manifold interindividual differences in plasma levels for maximal concentrations (9-170 ng/ml) as well as for minimal concentrations (4-96 ng/ml). The absorption profile in both studies has linear and nonlinear components. Maximal plasma levels were reached after about 4 h. Terminal elimination half-lives were about 20 h.
Ascites tumor cells growth-arrested in lipid-depleted medium were modified with respect to their lipid composition, i.e. mainly cholesterol and the phospholipid fraction. These so-called lipid-depleted cells were generally smaller, had a surface area reduced by 55% compared to the control cells and had an altered cell surface architecture with large parts being smooth, interrupted by isolated bundles of microvilli and blebs as revealed by scanning electron microscopy. This deorganization process of the cells. Lectin-induced agglutination and receptor binding capacity was reduced, and also the receptor distribution was changed resulting in a cap-like formation on the surface as shown with FITC-labelled concanavalin A. The reduction in lipid content yielding a lower C/P ratio profoundly decreased the plasma membrane fluidity which was determined by fluorescence polarization measurements. Studies on fatty acid and cholesterol de novo synthesis revealed only small increases under lipid-free conditions not sufficient to meet the requirements of the lipid-depleted cells for these substances. It is therefore concluded that ascites tumor cells need exogenous preformed lipids for adequate functioning of the cell.
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Capillary radioimmunoassay -- a modification of the coated tube technique -- is described. The assay is equivalent (accuracy, sensitivity, precision) to conventional methods for insulin determination; it overcomes, however, the necessity of centrifugation or filtration and offers the added bonus of being automation compatible.
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In an experimental study, employing anaesthetized dogs, it was investigated whether cellular enzymes from peripheral skeletal muscle get into the circulating blood by diffusion across capillary membranes or by lymphatic transport. In the experimental group 1, the animals were anaesthetized only. The plasma activities of the four enzymes measured--lactate dehydrogenase, aspartate aminotransferase, alanine aminotransferase, creatine kinase--did not show any mentionable change during a time period of 6 h. In group 2 one hind limb of each animal was moved passively for 1 h. Alanine aminotransferase remained unchanged in plasma, the activities of the three other enzymes increased significantly. In group 3 one hind limb was made hypoxic by clamping the femoral blood vessels for 1 h. No activity changes were observed. When the period of hypoxia was followed by a 1-hour period of passive movement in group 4, the alterations in plasma activities were almost identical to those observed in group 2. In group 5 the experimental procedure was as in group 4, in addition the lymph from the thoracic duct was quantitatively withdrawn. The enzyme activities in plasma revealed a tendency to decrease rather than increase. Lymph flow increased significantly as well as the lymphatic activities of those enzymes which have high intracellular activities in muscle. The results prove, that enzymes from muscle are transported from the interstitial into the intravascular compartment mainly by lymphatic transport. Indications were found that the interruption of blood flow in one hind limb did not result in an enzyme release from muscle cells. It is discussed how changes in lymph flow, occurring during physical exercise for example, affect enzyme activities in plasma.
The mechanism of enzyme release from isolated skeletal muscle was illustrated by the study of the release of lactate dehydrogenase (LDH). In hypotonic media of different composition but of same tonicity the increase of LDH permeability was triggered at the same range of relative osmolality R (0.45 less than R less than 0.55), although the swelling in the respective media showed appreciable differences. The kinetics of muscle swelling showed that a deviation from the theoretically computed swelling curve to lower values of swelling was connected with an increased LDH permeability. The reduction of swelling was ATP- and Ca2+ and/or Mg2-dependent. It is concluded that swelling of cells generally precedes the leakage of soluble enzymes, and the cross-linking of filaments at the sarcoplasmic side of the sarcolemma under appropriate conditions can counteract swelling, thereby blebbing off the cell membrane from the filament meshwork. In the course of this process, sufficiently large membrane lesions are produced through which macromolecules may escape into the extracellular space.
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Because of the increased number of samples to be processed in digoxin radioimmunoassay for clinical diagnosis and pharmacokinetic studies these analyses require mechanization to a certain extent. A newly developed modular analyzer system is described which is capable of mechanizing radioimmunoassays for digoxin, for example, independent on the kind of reagent kits as well as the separation technique. In dependence on the number of replicates from 60 to 240 samples per hour can be processed. The reaction vessels are placed in belts during the whole assay including centrifugation. The final separation of the liquid and the solid phase after centrifugation can be performed in two different ways: 1. If a conventional automatic gamma counter is used an aliquot of the supernatant is automatically dispensed into the counting vials which are to be closed manually and transferred into the counting device. 2. Further reduction of manual working steps can be achieved by employment of a newly developed discontinuous flow-through gamma counter which is part of the modular analyzer system. An aliquot of the supernatants is automatically flushed into a measuring cuvette installed into a conventional crystal detector. After measurement of the radioactivity and data output the cuvette is rinsed thoroughly. Thereafter the following sample is delivered.
A new modification of the "coated-tube"-technique for the radioimmunoassay of human placental lactogen is described. Polyvinylchloride capillaries are used as reaction-vessels. Most working steps of the test procedure are mechanized. The possibilities and limitations of the new technique are discussed. The reliability of the method was shown by a recovery test, dilution tests, reproducibility and a comparison of the results for 71 sera, ranging from the 6th to the 42nd week of pregnancy, with those obtained by a conventional assay procedure.