Tierärztliche Fakultät - Digitale Hochschulschriften der LMU - Teil 01/07 Archiv

Yersinia enterocolitica of bioserovar 4/O:3 is the most common pathogenic type found in pigs and pork including edible offal in Southern Germany. Limited epidemiological data is available of human Y. enterocolitica infections in Bayern. The sources and transmission routes of yersiniosis are not clear. This work was conducted to get more information on the epidemiology in Munich area. In the first part of this work, the human strains were isolated from faecal samples of patients with diarrhoea during the period from November 2001 to December 2002. Yersinia was isolated from the faeces using direct culturing on selective CIN agar plates. One typical colony per sample was identified using EnterotubeTM. All Yersinia strains were bio- and serotyped. In all, 61 Yersinia strains were isolated from 61 patients. Fifty-eight (95%) strains were identified as Y. enterocolitica of which 54 (93%) were belonging to pathogenic bieserovar 4/O:3, two (3%) strains to pathogenic bioserovar 2/O:9 and two to non-pathogenic biovar 1A. In 2002, Yersinia was found from 50 (0,21%) patients when 22.835 faeces samples were studied. Y. enterocolitica was identified in 48 (96%) cases. The bioserovar 4/O:3 was found in 44 (92%) patients and bioserovar 2/O:9 in two (4%) patient. Y. enterocolitica was found in all age groups and 60% of the patients were females. No seasonal variation was seen. Yersinia was the third most common bacterial pathogen after Campylobacter found in 805 (3,52%) faecal samples and Salmonella found in 681 (2,98%) samples. In the second part of this work, 36 human and 69 non-human Yersinia strains were characterised with PFGE. The human strains were isolated during the period from November 2001 to June 2002. The non-human strains were isolated between 1999 and 2002. Most (62/69) of these strains were from porcine origin. In total, 41 genotypes were obtained when the 105 strains were characterised with PFGE using NotI, ApaI and XhoI enzymes. The Yersinia spp. could easily be distinguished from each other with NotI enzyme. Twenty-four genotypes were obtained when the 84 strains belonging to bioserovar 4/O:3 was characterised with all three enzymes. Most (90%) of the human strains were indistinguishable from the non-human strains. These 26 indistinguishable human strains were belonging to 8 genotypes. The non-human strains were from porcine sources and isolated from carcasses, offal and pork. These results demonstrate that Y. enterocolitica is frequently isolated from patients with diarrhoea in Munich area. The most common type in humans is the bioserovar 4/O:3, which is so far the only pathogenic type found in pigs in Southern Germany. PFGE with NotI enzyme was useful tool to identify Yersinia spp. Using NotI, ApaI and XhoI enzymes, the strains of bioserovar 4/O:3 could efficiently be subtyped. A major infection source of human yersiniosis was revealed to be pork and edible offal.

Experimental investigations at the porcine over-sized coronary stent-model for in-stent-restenosis rate after implantation of uncoated niob-zirkonium stents and niob-zirkonium stents coated with iridiumoxide. Background: The treatment of atherosclerotic stenosis in coronary artery disease with balloon expandable coronary stents has been successfully practised in minimal invasive cardiology in the last two decades. Today almost all commercially coronary stents are made of stainless steel (316L) and there is a great variety in design and coatings available. Until now no interventional procedure has been successful to stop the vicious circle of arterial stenosis, intervention and restenosis. Methods: In 23 pigs (German land breed) Inflow Dynamics Starflex Design Stents were implanted into the LAD and LCX by random for 28 days. In the porcine over-sized coronary stent model three groups were compared: uncoated niob-zirkonium stents, niob-zirkonium stents coated with iridiumoxide and stainless steel stents (control group). The implantation procedure and angiography were documented and histological and histomorphometric studies were performed to interpret the in-stent-restenosis rate. The statistical evaluation of the differences between the test groups was done by the analysis of variance (One Way ANOVA-Test) and specified (Post Hoc-Test). Results: Three animals died postoperatively. 38 stents were evaluated. The implantation procedure in the experimental groups was complicated due to the elastic and plastic properties of the niob-zirkonium stents. The injury score (IS) and the measured neointimal area (NF) were significantly higher in the group of niob-zirkonium stents coated with iridiumoxide. The histomorphometric and angiographic parameters of restenosis did not point out any significant difference between the test groups. The histological response of the arterial wall after stent implanation provided a homogenous appearance of tissue shaped by the score of vascular irritation. Conclusion: A direct comparison in the stents of uncoated niob-zirkonium and niob-zirkonium stents coated with iridiumoxide with stainless steel stents was not possible. No new findings for the in-stent-restenosis rate were provided by the results of the control stents. The prototypes of the uncoated niob-zirkonium stents and the niob-zirkonium stents coated with iridiumoxide have to be optimized in their metallurgical characteristics to guarantee an implantation procedure without complications. The alloy niob-zirkonium and the iridiumoxide-coating are excellently biocompatible. Even SUMMARY 117 after a high vascular irritation the stents are embeded into a neointima with only a minimum of cellular response.

Ermittlung von Referenzbereichen für zelluläre Blutbestandteile beim geschlachteten Fleckviehmaststier Im Rahmen der vorliegenden Arbeit sollten Referenzbereiche für zelluläre Blutbestandteile beim geschlachteten Fleckviehmaststier ermittelt werden. Die Untersuchungen wurden an 514 Mastbullen der Rasse Deutsches Fleckvieh im Rahmen des Schlachtvorganges am Schlachthof München durchgeführt. Von den Probanden, die lediglich einer Lebendbeschau unterzogen wurden, wurde nach Bolzenschußbetäubung und Schnitteröffnung der Halsgefäße das daraus austretende Mischblut in einer 10 ml K-EDTA-Monovette aufgefangen. Jede dieser Proben wurde untersucht auf die Absolutzahlen der roten und weißen Blutkörperchen, den Hämatokrit, die Hämoglobinkonzentration und die Erythrozytenindices MCV, MCH und MCHC; es wurden Differentialblutbilder erstellt. Die Auswertung der gewonnenen Daten erfolgte mittels der für Referenzbereichsbestimmungen üblichen Perzentilentechnik. Es wurde ein Vergleich der gewonnenen Ergebnisse mit solchen aus der Literatur hinsichtlich exogener und endogener Einflüsse angestellt. Als Resultat wurde festgestellt, dass es große Unterschiede hinsichtlich des Alters und des Geschlechtes in der zellulären Blutzusammensetzung beim Rind gibt. Aus diesem Grund sollte bei Referenzbereichsangaben die untersuchte Population deklariert werden, damit Interpretationsirrtümer hinsichtlich des Gesundheitsstatus vermieden werden können. Zur Sicherung einer guten statistischen Qualität soll ein ausreichender großer Probenumfang gewählt werden. Die Übertragung der hier gewonnenen Daten kann nur auf Stiere erfolgen, die die im Titel genannten Bedingungen erfüllen. Sie sollen nicht in erster Linie, wie im klassischen Sinne der Referenzbereichsanwendung, Krankheiten aufdecken, sondern vielmehr helfen, Fehler im Management von Mastbetrieben zu erkennen.

The aim of these examinations was to check various flow cytometric methods to establish whether they are suitable objective methods for assessing the quality of cryopreserved sperm from stallions. The plasma membrane integrity, the mitochondrial membrane potential, the acrosomal status and the integrity of the chromatin structure in cryopreserved sperm from stallions were assessed. For this purpose various fluorescent stainings were carried out both immediately after the semen samples were thawed and after a three-hour period of incubation at 37 C with SYBR 14, JC-1 and SYTO 17 / propidium iodide / FITC-PNA and a sperm chromatin structure analysis (SCSA) and were then evaluated. The sperm quality parameters obtained by flow cytometry showed good reproducibility. The results of measurements of three different straws of an ejaculate which were carried out independently of each other did not differ significantly. The intra-class correlation coefficients were between 0.88 and 0.98. The flow cytometric tests evaluated in this examination were therefore considered to be reliable. In order to demonstrate the correlations between the routine examination methods for assessing the sperm quality and the analysis processes evaluated in this study, the viability and the morphology of the sperms after thawing were assessed by light microscopy using bromide phenol blue nigrosine smears. A computer controlled motility analysis was also carried out. Moderate correlations (0.60 > r > 0.58; p < 0.0001) were obtained between the viability assessed by light microscopy and the percentage of vital sperms obtained by flow cytometry. The proportion of progressively forward moving sperms correlated positively (r = 0.50; p < 0.01) to the proportion of sperms with a high mitochondrial membrane potential. The relationships between the results of the SCSA test and the proportions of both primary and secondary sperm anomalies were weakly pronounced (r = 0.24; p < 0.01). In the flow cytometric assessment of the viability, the mitochondrial membrane potential and the integrity of the acrosome it was shown that the ejaculate-related variations were approximately the same as the variations between the stallions. Regarding the results of the sperm chromatin structure the individual variations (88 - 91%) were considerably greater than those dependent on the ejaculate (9 – 12%). It was also shown that the results of the flow cytometric sperm quality assessment did not vary significantly in stallions which had a period (four months) of sexual rest before providing ejaculate compared to stallions which ejaculates were collected with a regular frequency. In terms of the animals’ age there was only a weak relationship (r = 0.43; p < 0.01) with integrity of the sperm chromatin structure. The results of the flow cytometric methods for assessing the viability (SYBR 14/PI, JC-1 and SYTO 17/FITC-PNA/PI combination staining) were comparable (r > 0.96; p < 0.0001). The latter is the only one of these tests which provides additional information about the integrity of the acrosome of the sperms. The combination of this triple staining with the sperm chromatin structure analysis (SCSA) also provides further important information about the sperm quality. To check the relationships between fertility of the stallions and the various sperm quality parameters obtained by flow cytometry, only seasonal pregnancy rates from fresh semen insemination were available. In terms of the viability and the acrosomal status of the sperms after thawing, these showed no correlations (p > 0.05) with the fertility of the stallions. On the other hand, a negative relationship was established between the integrity of the chromatin structure and the fertility of the stallions (r = - 0.51 / - 0.59). This study shows that the flow cytometric assessment of the quality of cryopreserved sperm from stallions represents a reliable and objective method. In addition to the routine assessment of sperm quality, it provides important additional information, for example about the intactness of the acrosome and the integrity of the sperm chromatin structure.

A total of 1248 animals was stunned in two EU approved slaughterhouses using either cartridge activated or pneumatic concussion stunning devices. In total, 12 % of the animals had to be stunned twice. If the shooting position deviated from the midline the rate of re-stunning increased considerably. In the main experiment carried out in the larger of the two slaughterhouses 67.8 % of the animals lay without any movement immediately after falling out of the stunning box. Pathological examinations carried out after splitting the skull longitudinally showed a low to high degree of haematoma formation in the brain in more than half of the animals stunned by concussion stunning. The haematomas were localized on the frontal side of the brain immediately beneath the stunning position and on the opposite side of the brain stem. The haematomas occurred also in animals the lamina interna and the dura mater of which were not injured. Following concussion stunning 69 electrocardiograms were made. Except for one animal which could not be evaluated all animals showed normal heart activity corresponding to that observed after captive bolt stunning. The examination of several meat quality parameters did not yield any clear deviations from meat maturation after captive bolt stunning. Meat color, pH value and temperature were measured in the Musculus longissimus dorsi. The most important conclusion of this study is that the application of concussion stunning can improve the safety of the slaughterhouse workers in several critical positions of the slaughtering line (stunning, hoisting and sticking). As long as the dura mater remains intact, the worker responsible for stunning does not come into contact with potentially infected brain material. In addition, after concussion stunning carcass stillness was clearly improved in comparison to captive bolt stunning. However, the results concerning animal welfare are still unsatisfactory as too many animals have to be stunned twice. With respect to consumer protection concussion stunning also does not offer advantages over captive bolt stunning since the distribution of nerval tissue via blood cannot be ruled out because of the haemorrhages occurring in the brain.

In the present study an efficient procedure for detecting salmonellas in feces of tortoises should be established. First of all a survey of occurrence of salmonellas in reptiles and their importance for reptiles as well as for man is given. Next an appropriate incubation temperature for multiplying salmonellas of reptilian origin in a selective enrichment medium was evaluated. Furthermore 86 salmonella strains isolated from reptiles were tested on nine different selec-tive solid media for their appearance; these media were BPLS-, DCLS-, HE-, MLCB-, ÖNÖZ-, RAMBACH-, SS-, WS- and XLD-Agar. The media were reviewed according to their qualification in identifying those strains. Finally 167 fecal samples of tortoises of different species and two lizards from Munich area were examined according to the former established procedure whether or not they harboured salmonellas. Therewith the suitability of this method should be determined and the incidence of salmonellas of these tortoises should be investigated. Following results were obtained: The best growth of salmonellas resulted from RAPPAPORT-VASSILIADIS and selenite cystine enrichment broth at an incubation temperature of 35-37 °C. The higher critical temperature for incubation of RAPPAPORT-VASSILIADIS enrichment medium is 42 °C; especially Salmonella subspecies IIIb often are inhibited in this medium at this temperature. For isolating salmonellae as well as for inhibiting competing organisms, an incubation temperature of 41 °C is emphasized for enrichment in RAPPAPORT-VASSILIADIS broth. Neither temperature investigated had any inhibitory effect on the growth rate of salmonellas in selenite cystine medium, but its inhibitory activity on competing organisms proved strik-ingly less, too. RAPPAPORT´s enrichment medium supports growing of salmonellas of reptilian origin least of all. For isolation of salmonellas from tortoises BPLS- and XLD-agar proved best for direct strik-ing as well as after previous enrichment in either RAPPAPORT-VASSILIADIS or selenite cystine medium or both. For investigation of snakes and lizards MLCB- or eventually WS-agar should be used. For achieving a most reliable statement at least two different agar media should be used for direct plating as well as for enrichment subculture. RAPPAPORT-VASSILIADIS and se-lenite cystine enrichment medium should be used simultaneously and spread on at least twice at different times of incubation. On account of the intermittent excretion of salmonellas sev-eral fecal samples should be examined. The more extended the effort the better the results will be. Though a single negative result never is absolutely reliable. In this study the incidence of salmonellas in tortoises – investigating only a single sample from each animal – ranks at about 10 %. Two out of 18 tortoises positive for salmonellas originated from different private owners; the remaining 16 belonged to two stocks of a pet shop. Therefore statements about higher incidence of wild cut or home bred tortoises were not practicable.

In the present study the data of 156 calves of different breeds, aged two to twelve weeks, with neonatal diarrhoea were evaluated retrospectively. The calves were in-patients in the II. Medizinischen Tierklinik of the LMU München in 1997 and 1999, where the necessary data were collected. The aim of this study was to find out, how certain easily obtainable findings change with the severity of the disease. This was conducted with the results of the macroscopic (colour, grade of cloudiness and pollution) and physical (specific gravity)urine examination, the serum- and urine-concentrations of creatinine (SCr and UCr), urea (SHst and UHst) and sodium and the parameters Ucr / Scr, UHst / SHst and EFNa. Factors that may lead to deviation of the results during sampling were additionally considered. It was revealed that especially the specific gravity and the colour of the urine sample are suitable for the confirmation of the clinically diagnosed degree of dehydration. The specific gravity increased from x = 1022.2 in non-dehydrated patients to x = 1029.3 in patients with severe dehydration. The colour of the urine sample, assessed macroscopically and subjectively, was stated to be darker with an increasing grade of dehydration. The quotient Ucr / Scr does not support the estimation of the grade of dehydration. Accompanied by an increasing dehydration serum concentrations of creatinine and urea and urine concentration of creatinine increased. The urine concentration of creatinine correlated to the specific gravity (r = 0.73) and significantly rose in samples of darker colour. The proportion of animals with an eliminated fraction of sodium (EFNa ) greater than 1% among patients with urine of light colour was remarkable. This corresponds to the findings that also an Ucr / Scr -quotient below 37 was frequently found in calves with urine of light colour. Both indicates a restricted renal function caused by impairment of the tubular reabsorption of sodium or glomerular filtration, respectively. To evaluate influences on the results of urine examination, that play a part during sampling, factors as spontaneous or provoked collection of urine, sex and grade of the samples´ cloudiness and pollution were taken into account. None of these lead to a distinct change of findings. The results of this study show the possibilities of an extended diagnosis of dehydration grade in calves with neonatal diarrhoea. An eventual damage of renal parenchyma may be suspected considering the Ucr / Scr –quotient and the EFNa . This might be important for the patient’s prognosis. The deviation of the findings of urine examination by factors of sampling is supposed to be of lesser importance for diagnosis.

This paper describes the development and application of enzyme immunoassays for the detection of antimicrobials in milk, aiming at the establishment of a biosensor system for the on-line analysis of drug residues in milk. For the development of group-specific antibodies against penicillins rabbits were immunized with an ampicillin-BSA-conjugate. The resulting antiserum was employed for the development of a direct competitive enzyme immunoassay (EIA), giving a detection limit of 1 ng/ml for penicillin G in milk. Due to broad cross-reactivities the sensitive detection of those penicillins regulated by MRLs within the European Union (ampicillin, amoxicillin, oxacillin, cloxacillin, dicloxacillin and nafcillin) was enabled. The practical use of the enzyme immunoassay was demonstrated by analyzing artificially contaminated and violative incurred milk samples (n = 321). For the development of indirect competitive enzyme immunoassays for the detection of streptomycin, sulfonamides and penicillins, previously established direct assays, based on monoclonal antibodies, were adapted to indirect formats. For this purpose a wide range of coating-antigens was prepared by linking haptens to carrier-proteins. After optimizing test sensitivity and characterizing the test specificity indirect EIAs could be developed for each antimicrobial compound, fulfilling the MRL requirements due to EU regulation 2377/90. Only for ampicillin and penicillin G colorimetric measurements resulted in detection limits of 7 and 6 ng/ml, respectively, which were slightly above the MRL of 4 ng/ml. By using a luminescent substrate, however, the MRL could be reached for these antibiotics as well. Based on the results of the individual EIAs rapid multianalyte tests both on microtitre plates and planar microarray chips were developed. Due to altered assay conditions again the systems were optimized and characterized regarding sensitivity and specificity. The sensitivities achieved on the biochip were well comparable with those obtained in the microtitre plate, whereas total assay time could be reduced to 15 min (microtitre plate) and 5 min (biochip), respectively.

The forces in the limb joints in the dog were investigated for the first time in the German Shepherd. The main focus lay on the joints of the forelimb, as these have been hardly investigated so far. But also the joint forces of the joints of the hind limb were demonstrated. Additionally the foundations for a forward dynamic model were developed for the forelimb. The study constitutes two parts. The aim of the first part was to develop the foundations for a forward dynamic model. For that reason the skeletal muscles of the forelimb as well as the shoulder girdle musculature of five German Shepherds were analysed. The length of the fibres, the weight and the angle of pennation for the muscle fibers were used to determine the physiological cross-section area. Individual extensive muscles of the shoulder girdle musculature were divided into various portions, for a better determination of the lines of actions for these muscles. The coordinates of the muscles various points of origin and insertion were measured on the skeleton of a German Shepherd. The straight line of these skeletal points were determined as action lines, in order to calculate the moment arm of the muscles. The physiological cross-section areas of the according muscles of the investigated dogs were significantly different in size. This is probably due to the different constitution of the dogs, in both the nutritional status and the condition. In the second part of the study the vertical and horizontal net joint forces and the moments of the limbs joints in a German Shepherd were analysed with the invert dynamic model. In order to determine the forces and moments, the data of the gait analysis coupled with the ground reaction forces and the inertial parameters of the individual limb segments were necessary. Furthermore the displacement of the superficial markers, which were attached to the skin were measured during the gait analysis. The net joint forces are greater in all of the joints of the forelimb than compared to those in the hindlimb. When the vertical net joint forces were taken into consideration the forces of the forelimb were even twice has large. Due to the positioning of the body’s centre of gravity closer to the forelimbs, these carry a greater load, which explains the greater forces in the joints of the forelimb. The horizontal forces in both limbs show a biphasic course. The time interval of the decelerating and accelerating forces are near to the same size. It also appears that the forelimb seems to slightly slow down the forward motion, as the decelerating forces are greater than the accelerating forces. The moments are also greater in the forelimb than in the hindlimb.

Pharmacologically enhanced manual semen collection and computer assisted sperm head morphometry in the white rhinoceros (Ceratotherium simum) In this study the influence and applicability of pharmacologically enhanced semen collection in the white rhinoceros (Ceratotherium simum) was investigated. Obtained semen samples were assessed by routine methods. Additionally, computer assisted sperm head dimensions were determined for 15 individuals and a morphometric analysis was performed. A combination of the alpha-2-agonist Detomidine-Hydrochloride (Domosedan) and the partial opioid agonist Butorphanol (Butomidor) was administered intramuscular. In order to provide adequate safety margins for the operating persons, important requirements consist in a restraint chute and conditioning of the rhinoceros to tolerate manipulations. In a double blind trial, conducted on two bulls of various age and breeding status, a strong positive influence of the alpha-adrenergic medication was noted on both, performance and the outcome of the manual desemination trials. The medication facilitated manual stimulation of the genital region and semen collection in both males, but was time consuming as repeated collection trials had to be performed in order to obtain a single ejaculate. Pharmacologically enhanced desemination trials with an artificial vagina could not induce ejaculations efficiently. The frequency of semen collection and semen quality varied considerably between the applied desemination techniques, but also between the rhinoceros bulls. Ejaculates collected by the pharmacologically enhanced manual stimulation technique were incomplete, consisted of small volumes (0,5 to 9,0 ml, with one exception of 23 ml), but were highly concentrated in some cases (total number of sperms up to 6,6 x 10E9 per ejaculate) and of good quality. Semen samples collected with an artificial vagina however, were of low quality and were contaminated by debris. Amongst other factors, the extensive duration of the penile erection in rhinoceroses, appears to limit the suitability of the artificial vagina for semen collection. The determination of sperm head dimensions in the white rhinoceros was based on a computer assisted morphometric analysis of ejaculates from 15 individuals. The samples consisted of pharmacologically enhanced manually collected semen and electroejaculates. The Hamilton Thorne Morphology Analyser IVOS (integrated visual optical system; Hamilton Thorne Research, Beverly, USA) allowed the measurement of six metric sperm head parameters. The sperm head dimensions found for the white rhinoceros with a mean length of 5,4 ± 0,3 micrometers and width of 2,8 ± 0,2 micrometers (x ± SD; n=7733 analysed sperms) resemble those of the horse as determined by the same analysis system (e.g. UHLENBROCK 1999). A definition of morphometric criteria was required prior to the morphometric analysis. Limit values for five morphologic categories were calculated based on statistic parameters (5. and 95. percentiles, minimum and maximum). The analysis revealed a comparatively broad variation in the number of sperm head anomalies for the 15 rhinoceroses, ranging from 4 to 16%. As to date, investigations on the relationship between morphometry and fertility cannot be conducted in this species, these morphometric results should be interpreted species-specific and in conjunction with further semen parameters. In conclusion, pharmacologically enhanced manual stimulation with an alpha-adrenergic medication is a suitable alternative method for repeated semen collection in the white rhinoceros, although problems with this method as described are evident. While a considerable variation in volume and concentration of the samples was noted for individual rhinoceros bulls, the sperm morphology and morphometry generally appeared homogenous.

Bone integration and biocompatibility of a new bioresorbable polymer for screw augmentation in the osteosynthesis of osteoporotic cancellous bone: The surgical treatment of an osteoporosis-associated fracture is a clinically relevant problem, which yet has no satisfactory solution. The fixation of conventional implants is limited because of the reduced bone density in osteoporotic bones. To ensure stable fixation compound osteosynthesis has been used since the 1950s. Polymethylmethacrylate (PMMA) is the most commonly used bone cement in reconstructive medicine because of its excellent mechanical properties. However, compound osteosynthesis also has some disadvantages. The local exothermic polymerization as well as the release of toxic residual monomers can cause damage to the surrounding tissue. PMMA is also not resorbable, and therefore surgeries using PMMA are irreversible. An ideal absorbable bone cement must meet many biochemical requirements and also provide sufficient mechanical stability. Two critical requirements are long-term biocompatibility, and an absorption rate that corresponds with the reestablishment of the physiologic bone stability. The aim of this study was to investigate different variations of a new resorbable bone cement developed on an alkylene bis(dilactoyl)-methacrylate basis in terms of long-term biocompatibility, degradation and mechanical reinforcement in a sheep model. Further, the suitability of ovarectomized sheep as osteoporotic large animal model was verified for investigation of biomaterial. In this study osteoporosis was generated in sheep by an ovarectomy followed by 6 months of glucocorticoid injections. The control group received no treatment. Two screws were implanted in the cancellous bone in the distal femur and proximal tibia in both groups. The screws were fixed in the bones with variations of the new bone cement. In each group, three screw fixation techniques were investigated: augmented with the new polymers, augmented with PMMA, or not augmented. The ovarectomized sheep were sacrificed after eight weeks (short-term group). The control sheep (long-term group) were sacrificed after six months. Histology results confirmed the biocompatibility of the non-augmented screws as well as the screws augmented with PMMA in both the short- and long-term group. Histology of the cancellous bone showed physiologic remodeling zones. The new polymers were homogenous after eight weeks, with no signs of degradation. The polymer was well distributed in the cancellous bone, but there were no signs of osseous integration of the cement. Only a small number of inflammatory cells were present. However, a significant inflammatory response with macrophages, giant cells and erythrocytes was observed six months after implantation. Massive osteolysis was seen and in some cases so severe that the screw was loose. The degradation kinetics of the new polymers were unsatifactory, because there was no decrease in the volume of the applied bone cement after six months. There is no definitive answer as to what caused the foreign body reaction. Most likely several factors played a role, such as cytotoxicity of the degradation products, particles were broken off and the increased osmotic pressure within the implantation site. The inflammatory reaction and the degree of osteolysis depended without a doubt on the concentration of the polymer. The macroscopic and histologic changes in the osseous implantation site were consistent with the biomechanical results. The mechanical strength of the screws fixation of the new polymers measured by pullout force was significantly less at both eight weeks and six months compared to the screws in the control group. The screws fixed with the new polymer lacked osseous integration and also had poor biocompatibility. Therefore, the new polymers do not meet the requirements for clinical use. The use of ovarectomized sheep treated with glucocorticoids proved to be a suitable animal model for investigating biomaterials in osteoporosic bone. The density of the cancellous bone in the extremities was significantly decreased, compared to the control animals.