Search

Difficult fractures of the calcaneus are therapeutic problem today. From 1965 to 1977 147 patients were non-operative treated in the department of general surgery - including cases from department of orthopedic surgery. 67 patients with fractures of the os calcis were controlled between 3 and 15 years after accident. The various methods of conservative treatment are discussed. The early functional treatment had the better late results than other conservative methods i.e.: fewer pain and better flexibility of the talo-calcaneo-navicular and talo-calcanean joint, sooner taking up of the former occupation and lower decrease in performance.

The flavor of boiled potatoes was investigated using sensory and instrumental methods to get basic information concerning sensory features and aroma compounds for use in breeding research and quality control. The sensory odor profiles of three genotypes were found to differ especially in negative sensations like “burnt”, “fodder” and “musty”. The aroma volatiles were isolated by a modified simultaneous steam distillation and extraction method. Nineteen character impact compounds of boiled potato aroma were pointed out by gas chromatography with nitrogen specific detection, gas chromatography —mass spectrometry and gas chromatography —olfactometry. The comparison of the quantified odor impressions in three genotypes by chromatography —olfactometry revealed the substances responsible for the typical boiled potato odorants and off-flavor notes.

Aim of this case-control study, performed on 412 male bladder cancer cases and 414 controls with benign prostatic hyperplasia in a former area of coal, iron and steel industries in Germany, was to identify occupations with an increased bladder cancer risk. In bladder cancer cases, smokers were overrepresented (58.3 %) compared to controls (35.2 %). The percentage of patients who had stopped smoking for at least 10 years did not differ in cases (10.2 %) and controls (9.7 %). Significantly elevated smoking-adjusted bladder cancer odds ratios (MH) were observed in painters and lacquers (MH 2.24, 95 % CI 1.07–5.13), chemistry-related occupations (MH 2.44, 95 % CI 1.05–5.67), coke plant workers (MH 2.89, 95 % CI 1.16–7.16) and hard coal miners (MH 2.33, 95 % CI 1.52–3.58). Significantly decreased smoking-adjusted bladder cancer odds ratios (MH) were observed in businessmen (MH 0.64, 95 % CI 0.45–0.92) and office personnel (MH 0.58, 95 % CI 0.41–0.81). In these two groups a relevant exposure to occupational bladder carcinogens is not likely.

Fire resistance of structures, systems and components (SSC) is widely identified as a fundamental issue for fire risk assessment at nuclear power plants (NPP). It is currently supported by several national or international ambitious experimental programs. Fire risk assessment at NPPs is performed under a series of hypothesis, e.g. the fire load. A problem will arise if tests used for conformity assessment do not appropriately represent the hypothesis selected during the fire risk analysis. In this case, SSCs may possibly be not meeting the expectations related to their fire resistance capacity supposed by the fire risk analysis. Ways of tackling this issue involve a regulatory approach and adapted requirements for components. While the widespread regulatory approach consists in seeking enveloping scenarios and conservative assumptions, a better knowledge of SSCs behaviour under for NPPs typical situations may be also desirable. The Institute for Energy of the European Commission's Joint Research Centre (JRC) at Petten (NL) launched a questionnaire with the aim of gathering opinions of regulatory bodies and their technical support organisations and manufacturers in Europe on this topic. Major goal was to estimate the relevance of the issue according to the perception of the specialists. The present paper collects the answers given by seven entities (AREVA, GRS, iBMB, IRSN, SJUB, SUEZ-TRACTEBEL, and VTT) and makes suggestions for addressing the issues identified by the participants.

The application of optimal power flow for the evaluation of wheeling and nonutility generation (NUG) related options is presented. Both wheeling and NUG options affect vital attributes such as system security, voltage profile, losses, and VAr reserves. These options put a strain on the existing transmission system and may restrict economic utility dispatching. Optimal power flows may be used to determine the best control settings to accommodate wheeling or NUG options so as to maintain system security while minimizing losses or production cost. Short-term marginal wheeling costs may be derived using optimal power flows. Case studies involving the Northeast Utilities and IEEE test systems are presented. These cases show that optimal power flows can be used effectively to address a broad range of wheeling or NUG related planning issues. >

The capabilities required of an optimal power flow (OPF) program are discussed. The architecture and functionality of an information-oriented shell built around GE's OPTIFLOW OPF program are described. The shell enhances the program's user friendliness, input data quality, and maintainability. It provides guidance to the user in selecting the appropriate control options. It also alleviates the need for performing mundane bookkeeping tasks such as managing or storing the input data sets by incorporating automated data handling and manipulation capabilities. The key components of the shell are a central database for improved data consistency, integrity, and security; an interactive user interface with detailed online context-sensitive help for improved productivity and efficiency; and an executive for transparently controlling the interaction between the different components of the system. All the shell components and the OPF program can run on 80386-based personal computers, workstations, and mainframes. >

Gallstone disease is a common disorder with a prevalence of approximately 20 % in industrialized countries. We performed a genome-wide disease association scan of over 500,000 single nucleotide polymorphisms (SNPs) using 280 cases with early onset gallstone disease and 360 sonographically stone-free controls from Germany. A total of 238 lead SNPs were identified, based upon their marker- and region-specific levels of statistical significance, and were subsequently followed-up in another 1100 symptomatic cases and 850 controls. The original disease association was replicated for only one marker, a SNP (Affymetrix id: A-1791411) in the ABCG8 gene (allelic p = 4.1 × 10−9). Fine-mapping of the ABCG5/ABCG8 locus, using both haplotype and logistic regression analysis, revealed that nonsynonymous SNP rs11887534 in the ABCG8 gene (encoding a D19H amino acid substitution) was found to represent the major source of gallstone risk at this locus. Its association with gallstone disease was further replicated in another 728 patients from Germany (p = 2.8 × 10−7) and in 167 patients from Chile (p = 0.02). The overall odds ratio (OR) for D19H carriership, as estimated from all German samples combined, was 2.2 (95 % CI 1.8–2.6). In a post-hoc logistic regression analysis, the genotypic effect was found to be independent of known risk factors such as BMI, age and sex. The association with D19H was strongest (OR = 3.3; 95 % CI: 2.5 – 4.3)) in the subgroup of patients with gallstones that contained cholesterol as a major constituent (> 30 %). The ABCG8 protein forms a heterodimer with ABCG5 that actively transports cholesterol into the bile. Since the His19 allele has been shown before to be associated with lower serum cholesterol levels, it appears likely to exert its gallstone predisposing effect by a more efficient transport of cholesterol into the biliary lumen and, therefore, a higher concentration of cholesterol in the bile.

Aim of this case-control study, performed on 412 male bladder cancer cases and 414 controls with benign prostatic hyperplasia in a former area of coal, iron and steel industries in Germany, was to identify occupations with an increased bladder cancer risk. In bladder cancer cases, smokers were overrepresented (58.3%) compared to controls (35.2%). The percentage of patients who had stopped smoking for at least 10 years did not differ in cases (10.2%) and controls (9.7%). Significantly elevated smoking-adjusted bladder cancer odds ratios (MH) were observed in painters and lacquers (MH 2.24, 95% CI 1.07-5.13), chemistry-related occupations (MH 2.44, 95% CI 1.05-5.67), coke plant workers (MH 2.89, 95% CI 1.16-7.16) and hard coal miners (MH 2.33, 95% CI 1.52-3.58). Significantly decreased smoking-adjusted bladder cancer odds ratios (MH) were observed in businessmen (MH 0.64, 95% CI 0.45-0.92) and office personnel (MH 0.58, 95% CI 0.41-0.81). In these two groups a relevant exposure to occupational bladder carcinogens is not likely.

In recent years, fluorescence microscopy imaging has become an important tool for studying cell structure and function. This non invasive technique permits characterization, localisation and qualitative quantification of free ions, messengers, pH, voltage and a pleiad of other molecules constituting living cells. In this paper, we present results using various commercially available fluorescent probes as well as some developed in our laboratory and discuss the advantages and limitations of these probes in confocal microscopy studies of the cardiovascular system.

The newly discovered neuropeptide nociceptin (NC) (alias orphanin FQ) was tested for its potential direct effects as well as for its ability to modify the electrically evoked contractions in several isolated organs suspended in vitro. NC was inactive both as stimulant and as inhibitor of smooth muscle in several preparations, whereas it inhibited the contractions induced by electrical field stimulation in the mouse vas deferens and guinea pig ileum. NC showed the same potency (IC50 = 10 nM) in the two preparations. However, it was significantly more effective in the mouse vas deferens (maximal effect -80%) than in the guinea pig ileum (maximal effect -50%). The inhibitory effect exerted by NC in the two preparations was not affected by naloxone or more selective opioid receptor antagonists. Moreover, by truncation of C-terminal sequences, NC fragments were designed. These fragments were subsequently tested in the mouse vas deferens and in the guinea pig ileum: NC(1-13)-NH2 was the smallest peptide maintaining the same efficacy and potency as the natural peptide. Finally, NC-NH2 and its fragments NC(1-13)-NH2 and NC(1-9)-NH2 were modified by substituting the phenylalanine 1 residue with a tyrosine. These peptides were tested in the guinea pig ileum, where they behaved as mixed NC-opioid receptor agonists ([Tyr1]NC-NH2 and [Tyr1]NC(1-13)-NH2) or as pure opioid receptor agonists ([Tyr1]NC(1-9)-NH2. In conclusion, the present paper demonstrated that the electrically stimulated mouse vas deferens and guinea pig ileum can be used as a sensitive bioassay for studying the pharmacology of NC and related compounds.

Contractile responses to B1 and B2 receptor agonists have been demonstrated in the mouse stomach; the mouse urinary bladder responds only to B2 receptor agonists. These tissues were used in this study to investigate the antagonistic effect of four B2 receptor antagonists, namely, DArg[Hyp3,DPhe7,Leu8]BK (BK, bradykinin), HOE-140, WIN 64338, and FR-173657 (B2 receptor antagonists), as well as three B1 kinin receptor antagonists; [Leu8]desArg9BK, Lys[Leu8]desArg9BK, and AcLys[D beta Nal7,Ile8]desArg9BK, were investigated. Results shown indicate that DArg[Hyp3,DPhe7,Leu8]BK is a partial agonist, while HOE-140 and FR-173657 are pure antagonists, devoid of direct myotropic effects, and quite selective for the B2 receptor. WIN 64338 was essentially inactive on both B1 and B2 receptors. The myotropic effect of DArg[Hyp3,DPhe7,Leu8]BK is blocked by HOE-140. Similarly, Lys[Leu8]desArg9BK and [Leu8]desArg9BK are B1 receptor partial agonists whose activities are blocked by AcLys[D beta Nal7,Ile8]desArg9BK (code name R 715), a fairly pure B1 receptor antagonist. Both HOE-140 and FR-173657 are long-acting, slowly reversible compounds that exert a noncompetitive type of antagonism, while R 715 is rapidly reversible and, thus, possibly competitive. Data presented in this paper provide a pharmacological characterization of B1 and B2 receptor antagonists in the mouse and underline the positive features of FR-173657 as a potent and selective B2 receptor antagonist, as well as the potency and purity of R 715 as a B1 receptor antagonist in the mouse.

To develop a new family of endothelin-converting enzyme (ECE) inhibitors, we assessed the inhibitory properties of an N- and C-terminal-truncated analogue of big endothelin (ET)-1[1-38], [Phe22]-big-ET-1 [19-37], on the renal vasoconstrictor properties of big ET-1 and ET-1. We had previously shown that a 60-min infusion of phosphoramidon (100 microM) potently inhibits big-ET-1 but not ET-1-induced vasoconstriction in the rabbit perfused kidney. A 1-min preinfusion of the analogue (100 microM) was sufficient to markedly blunt the vasoconstrictor actions of big ET-1 (250 pmol) (control 19.3 +/- 1.0 mm Hg; in presence of [Phe22]-big ET-1[19-37] 4.8 +/- 1.6 mm Hg; n = 6, p0.001). A 10- and 60-min preinfusion of the substrate analogue at concentrations of 50 and 5 microM, respectively, reduced the response of big ET-1 to 9.3 +/- 2.3 mm Hg and 3.6 +/- 1.8 mm Hg (n = 3, p0.01 compared to control). [Phe22]-big ET-1[19-37] was inactive against ET-1-induced vasoconstriction (10 pmol) and was devoided of intrinsic vasoactivity. All experiments were performed on kidneys pretreated with SQ-28603 (1 microM), a neutral endopeptidase inhibitor. Our results suggest that [Phe22]-big ET-1[19-37] may be a useful lead molecule for the development of more selective and enzyme-resistant inhibitors of the membrane-bound ECE.

The relationship between alpha-helical secondary structure and the fluorescence properties of an intrinsic tryptophan residue were investigated. A monomeric alpha-helix forming peptide and a dimeric coiled-coil forming peptide containing a central tryptophan residue were synthesized. The fluorescence parameters of the tryptophan residue were determined for these model systems at a range of fractional alpha-helical contents. The steady-state emission maximum was independent of the fractional alpha-helical content. A minimum of three exponential decay times was required to fully describe the time-resolved fluorescence data. Changes were observed in the decay times and more significantly, in their relative contributions that could be correlated with alpha-helix content. The results were also shown to be consistent with a model in which the decay times were independent of both alpha-helix content and emission wavelength. In this model the relative contributions of the decay time components were directly proportional to the alpha-helix content. Data were also analyzed according to a continuous distribution of exponential decay time model, employing global analysis techniques. The recovered distributions had "widths" that were both poorly defined and independent of peptide conformation. We propose that the three decay times are associated with the three ground-state chi 1 rotamers of the tryptophan residue and that the changes in the relative contributions of the decay times are the result of conformational constraints, imposed by the alpha-helical main-chain, on the chi 1 rotamer populations.

Human parathyroid hormone (hPTH) and several deletion analogues were examined for the presence of secondary structure using circular dichroism spectroscopy. The spectra of hPTH and the deletion analogues 8-84, 34-53, 53-84, 1-34, 13-34, 1-19, and 20-34, in neutral, aqueous buffer, gave no evidence for extensive secondary structure. An alpha-helical-like spectral contribution was found to arise from a region within peptide 13-34. This spectral contribution was speculated to arise from partial stability of a helix consisting of residues 17-29. Molecular dynamics simulations of peptide 1-34 suggested that this peptide tends to fold with a bend defined by residues 10-14, with the amino-terminal and carboxyl-terminal residues tending to be in more extended forms and the other residues in helical-like conformations. The addition of trifluoroethanol promoted the formation of alpha-helix, mainly in the 1-34 region. The putative helix comprised of residues 17-29 was stabilized by the addition of 10-20% TFE, while a second putative helix proximal to the amino terminus, and comprised of residues 3-11, was stabilized by slightly higher concentrations of TFE. An amphiphilic sequence was identified within the 20-34 fragment. The development of alpha-helix on binding this fragment, and other analogues containing this sequence, to palmitoyloleoylphosphatidylserine vesicles provided experimental evidence for the potential role of this amphiphilic sequence in binding to membranes or to a membrane receptor. The relationships between these alpha-helical regions in 1-34, either potentiated by trifluoroethanol or lipid vesicles, are discussed in terms of different receptor-binding regions within hPTH.

Specific degenerate codons in the amino-terminal region of a synthetic human parathyroid hormone (PTH) gene exerted dramatic effects on both products and yield of expression of this 84-amino acid polypeptide in Escherichia coli. With adenine-rich degenerate codons constituting the PTH-(1-5) region, intact PTH has been expressed as the only PTH product at 6.5 mg/liter. In contrast, with guanine-rich degenerate codons, the predominent product was analogue PTH-(8-84). Use of cytosine- or thymine-rich degenerate codons generated only a small amount of immunoreactive product (0.2 mg/l). With the amino terminal region reconstituted with adenine-rich degenerate codons, the mid and carboxyl regions of the synthetic gene were also reconstructed to imitate the E. coli-favored codon degeneracy. Expression yielded the intact PTH at 20 mg/liter. Gel electrophoresis and Western blots, with antibodies specific to the amino or carboxyl terminus of PTH, indicated only a single PTH-related polypeptide, with the same mobility as a synthetic intact PTH sample. Amino acid sequencing, composition analysis, mass spectrometry, and the adenylate cyclase bioassays confirmed the purified product as the processed intact PTH.

A section of an actual power system was modelled on a Transient Network Analyzer for the purpose of defining high frequency transient voltages occuring during switching events. The variety of system switching events which were staged produced oscillatory voltages covering a broad band of frequencies. On a digital model of the system autotransformers it was demonstrated that such oscillatory voltages could excite internal natural frequencies, but none of the actual generated waves coincided closely with the particular transformer natural frequency. However, if the applied waveshapes were frequency-scaled to a closer match, internal response voltages of concern could be developed.

Injuries to the epiphysel plates without involvement of the epiphyses or metaphyses, such as crush fractures or pure epiphysiolysis may be difficult to diagnose radiologically. Thirteen bone scans after damage to the growth plate have been performed on eight children. These indicate that these scans are able to diagnose lesions of the epiphyseal plates at an early stage and with certainty. The scintigrams also provide information concerning the healing process of the plate; they indicate when healing has been completed and when the extremity can be used for weight-bearing again. Radiation exposure of the children during scintigraphy with 99mTc-polyphosphate is within acceptable limits.

Oberarmschaftbruche sind auch heute noch die Domane konservativer Frakturenbehandlung. In einigen Fallen ist bei exakter Indikationsstellung ein operatives Vorgehen angezeigt. Die nach den Richtlinien der AO durchgefuhrte Druckplattenosteosynthese gewahrt eine Ubungsstabilitat und verhindert Rotationsfehler und Distraktion. Alle an unserer Klinik nach den Richtlinien der AO mit Druckplattenosteosynthese versorgten Frakturen heilten knochern fest aus.

Energiereiche Strahlen konnen am Magen-Darm-Kanal Fruh- und Spatreaktionen auslosen. Zu den letzteren zahlen Ulcera, Blutungen, Stenosen und Fisteln. Haufigste Ursache einer Strahlenreaktion ist eine vorangegangene Strahlentherapie wegen eines Uterus-Ca. Die chirurgische Behandlung mus sich oft auf die Anlegung einer Colostomie zur Kotableitung beschranken. Darmresektionen durfen nur weit im Gesunden vorgenommen werden. Die Letalitat chirurgischer Eingriffe wegen Strahlenfolgen am Darm betragt 25 %.

From 1957--1977 193 patients were treated at the surgical clinic of the University of Tubingen for carcinoma of the extrahepatic bile ducts. Gall bladder carcinoma made up 139 cases; 54 were of bile duct carcinoma. The tumors were no longer operable in two-thirds of the patients with extrahepatic bile ducts cancer. The life expectancy rate of five years for patients with gall bladder carcinoma held for 7%. Up to now only one patient with a bile duct malignancy has survived longer than five years. In the last decade essentially no improvement of median life expectancy has occurred despite improved operating techniques. Due to uncharacteristic, misleading upper abdominal symptoms, patients who suffer gall bladder or bile duct cancer are unfortunately accurately diagnosed only after the carcinoma has overcome organ borders or is already metastatic. There is reasonable hope for improved early prognosis of extrahepatic bile duct carcinoma with ERCP (Endoscopic Retrograde Cholangio-Pancreaticography) and computer-tomography. Because the possibility of a relationship between gall bladder stones and/or the chronic inflammation of gall bladder and bile ducts and the development of cancer is not out of the question, widespread prophylactic cholecystectomy and gall passage cleansing should be employed.

The Transient Network Analyzer (TNA), an electromagnetic analog of a power system, is used to study the transient voltages due to switching operations. This paper describes how a mini-computer has been used to enhance the operations of the TNA. The interfacing of the mini-computer and the TNA allows digital control of the TNA switching operations and provides a means of making sophisticated measurements and analyses of the results of that switching.

The one layer anastomosis after Gambee is compared with the two layer anastomosis after Dick at the small bowel of 20 minipigs. The end-to-end anastomosis after Gambee consists of an interrupted, inverting suturing of the bowel wall. Dick suggested a closed method, applying bronchial clamps before resecting the bowel. Seromuscular sutures and inner all layer sutures are inserted interrupted. Experimental studies have been done after 4, 7, 14 and 21 days. In Histology two layer anastomoses caused delayed wound healing after 4 days. Twenty-one days after the operation histological findings in both groups were equal. Microangiographic studies showed, that in single layer anastomoses revascularization began 3 days earlier than in two layer anastomoses. Measuring of the bursting strength showed no significant differences. All parameters suggest equal value of both techniques. In our opinion the two layer anastomosis after Dick combines the advantages of a closed method with a simple, easy performable technique. We therfore apply it all over the gastrointestinal tract with exception of esophagel and rectal anastomoses.

This paper outlines the results of a general transient network analyzer study on a 765 kV circuit to determine the phase-to-ground switching surge overvoltages for a variety of circuit breaker and transmission line conditions. The circuit was modelled after the standard transmission line as specified in ANSI standard C37.071a- 1974. An electronic differential analyzer was used to control the transient network analyzer and to rapidly measure switching surge statistical data. The results are given in terms of curves showing the variation in surge magnitudes with network and circuit breaker parameters including closing span, insertion time, insertion resistance and compensation.

Between 1970 and 1980 53 children with epiphyseal injuries were treated. Analysing these 53 cases we found that metaphyseal lesions of the epiphyseal plate (i.e. epiphyseolysis, separation of the epiphysis with triangular metaphyseal fragment) heal completely, even in those cases in whom an open reduction was necessary. Conservatively treated epiphyseal injuries (i.e. fracture of the epiphysis, crushing of the epiphyseal plate) showed bad results. Contrary to these results 80% of open reduced injuries showed good results. We can conclude that epiphyseal injuries do not necessarily end in disturbances of growth or malformation if surgical correction of the injury is done as early as possible and if the injured extremity is immobilised at least 3 to 5 weeks. Destruction of the epiphyseal vascular system can only be avoided by surgical reposition of the epiphyseal injury.

The concept of optimal power flow (OPF) is defined, and security-constrained OPF (SCO) is described. Two examples are presented to show how the SCO program provides enhanced capability for the utility engineer in solving problems. One deals with VAr support for transmission system expansion, and the other concerns substation capacitor bank location. >

Es werden die Ergebnisse der konservativen Behandlung distaler Radiusfrakturen bei 303 Patienten uber einen Entstehungszeitraum von zwei Jahren dargestellt. 226 Patienten konnten im Rahmen einer Nachuntersuchung erfast werden. 78% aller Frakturen heilten zufriedenstellend aus, wahrend die Ergebnisse bezogen auf die verschiedenen Altersgruppen zum Teil erheblich differieren. Neben der Darstellung der funktionellen und anatomischen Resultate in bezug auf Alter, Geschlecht und Lokalisation wird auf die Technik der Frakturenbehandlung sowie die Nachbehandlung eingegangen.

The discrepancies between measured and calculated small-signal space-charge wavelengths are discussed. It is shown that conventional methods of calculation are inadequate, causing errors up to 40 percent in a typical case. It is demonstrated that these errors cannot be explained by beam scalloping action, and that they are most severe when a high-perveance beam is used at low voltages with a high magnetic field under conditions of low interception. Although these effects would not be noticed in klystrons with relatively short drift lengths, they may in many cases explain the critical variation of gain and efficiency with magnetic field. A more accurate method of calculating space-charge wavelengths is developed, and the effectiveness of this method is demonstrated by a comparison with measurements.

Aus einem gro\en Beobachtungsgut sind funf instruktive Einzelfalle von gewaltsamem Tod Hirnverletzter ausgewahlt worden, bei denen auf Grund der polizeilichen Todesermittlungen ein Suicid angenommen worden ist. Erst nach Erganzung der Unterlagen konnte in jedem Einzelfall eine klare und ubersichtliche Verlaufsanalyse herausgearbeitet werden, die dann den wahren Sachverhalt erkennen lie\. Episodische Bewu\tseinstrubungen und Dammerzustande bei Hirntraumatikern fallen der Umgebung haufig gar nicht auf, sogar von arzten werden sie gelegentlich ubersehen. Nicht nur fur die Umgebung, vielmehr fur sich selbst sind solche Kranke erheblich gefahrlich, wie auch die hier mitgeteilten Beobachtungen zeigen. Eine einwandfreie Klarung solcher Falle ist aber nicht nur vom forensisch-medizinischen Standpunkt aus erforderlich, sie hat auch vom versicherungs- und versorgungsarztlichen Standpunkt aus auschlaggebende Bedeutung.

A ten-stage electrostatic depressed collector, designed with the aid of an analog computer, was tested on a 1-kW CW 750-MHz klystron. Excellent correlation was achieved between computed and measured performance under varying conditions of RF drive. At full RF power output approximately 60 percent of the spent beam energy was recovered by use of the depressed collector. The net power conversion efficiency of the tube was raised from its undepressed value of 54.3 percent to approximately 70.9 percent. At one-half full power output, a collector efficiency of 70 percent was measured. At zero RF power output collector efficiency was 80 percent. To achieve these results it was necessary to install a small focusing coil between the final drift tube and the collector. No spurious oscillations or instabilities were detected when collector depression was employed, nor was electron backstreaming increased significantly. Intentional short circuiting of adjacent collector electrode pairs was shown to cause only minor degradation in collector performance.

In spongiosen Knochenabschnitten erreichen Schraubenverankerungen erheblich niedrigere Werte als in corticalen. Vor allem der porotische Knochen gibt hierbei wenig Halt. Nicht die Biegesteifigkeit der Schraube sondern die Pressung des Knochens entscheidet uber den festen Schraubensitz (3). Kraftschlussige Verankerungen werden in der Technik durch den Einsatz zahelastischer Werkstoffe dort erreicht, wo die Schraubenbefestigung im Implantatlager nicht genugend Pressung erzielen kann.

Difficult fractures of the calcaneus are therapeutic problem today. From 1965 to 1977 147 patients were non-operative treated in the department of general surgery - including cases from department of orthopedic surgery. 67 patients with fractures of the os calcis were controlled between 3 and 15 years after accident. The various methods of conservative treatment are discussed. The early functional treatment had the better late results than other conservative methods i.e.: fewer pain and better flexibility of the talo-calcaneo-navicular and talo-calcanean joint, sooner taking up of the former occupation and lower decrease in performance.

In two groups of six beagle dogs a standardized bone defect of 1 cm was replaced by a) "Kieler Spongiosa", and b) autologous bone material, prepared according to the formula of Urist. Instead of mechanical insufficiency an impressive osteogenetic potency and periosteosis was noticed in group b.