Erythropoietin does not improve fracture healing in aged mice.

Fracture healing in the elderly is associated with a declined healing potential caused by multiple factors including a delay of vascularization. Erythropoietin (EPO) has been demonstrated to improve vascularization and fracture healing in adult mice. We, therefore, hypothesized that EPO in aged mice also improves fracture healing. For this purpose, EPO was given daily in a femoral fracture model in aged mice and compared to vehicle-treated controls using radiological, biomechanical, histomorphometric and Western blot techniques. Blood analyses revealed significantly higher concentrations of hemoglobin and a higher hematocrit in EPO-treated animals at 14 and 35 days after fracture. Micro-computed tomography (µCT) indicated that the fraction of bone volume/tissue volume within the callus did not differ between the two groups. However, µCT showed a 3-fold increased tissue mineral density (TMD) in the callus of EPO-treated animals compared to controls. The callus TMD of the EPO-treated animals was also 2-fold higher when compared to the TMD of the unfractured contralateral femur. Interestingly, biomechanical analyses revealed a reduced bending stiffness in femurs of EPO-treated animals at day 35. The histomorphometrically analyzed callus size and callus composition did not show significant differences between the study groups. However, Western blot analyses exhibited an increased expression of osteoprotegerin (OPG), but in particular of receptor activator of NF-κB ligand (RANKL) in the callus of the EPO-treated animals. Further histological analyses of the callus tissue showed that this was associated with an increased number of newly formed blood vessels and a higher number of tartrate-resistant acid phosphatase (TRAP)+ cells. Conclusion: In fracture healing of aged mice EPO treatment increases callus TMD as well as OPG and RANKL expression, indicating an accelerated bone turnover when compared to controls. However, EPO does not improve fracture healing in aged mice. The process of fracture healing may be altered by EPO due to a deterioration of the microcirculation caused by the worsened rheological properties of the blood and due to an increased bone fragility caused by the accelerated bone turnover. Thus, EPO may not be used to improve fracture healing in the elderly.

[A new continuous gait analysis system for ankle fracture aftercare]. / Ein neues, kontinuierliches Ganganalysesystem zur Nachbehandlung von Sprunggelenkfrakturen.

BACKGROUND: Correct aftercare following lower extremity fractures remains a controversial issue. Reliable, clinically applicable weight-bearing recommendations have not yet been defined. The aim of the current study was to establish a new gait analysis insole during physical therapy aftercare of ankle fractures to test patients' continuous, long-term compliance to partial weight-bearing restrictions and investigate whether patients can estimate their weight-bearing compliance. MATERIALS AND METHODS: The postoperative gait of 14 patients after operative treatment of Weber B-type ankle fractures was monitored continuously for six weeks (OpenGO, Moticon GmbH, Munich). All patients were instructed and trained by physical therapists on how to maintain partial weight-bearing for this time. Discontinuous (three, six and twelve weeks) clinical (patient questionnaire, visual analogue pain score [VAS]) and radiographic controls were performed. RESULTS: Despite the set weight-bearing limits, individual ranges for overall weight-bearing (range 5-107% of the contralateral side) and patient activity (range 0-366 min/day) could be shown. A good correlation between weight-bearing and pain was seen (rs = -0.68; p = <0.0001). Patients significantly underestimated their weight-bearing time over the set limit (2.3 ± 1.4 min/day vs. real: 12.6 ± 5.9 min/day; p < 0.01). CONCLUSIONS: Standardized aftercare protocols and repeated training alone cannot ensure compliance to postoperative partial weight-bearing. Patients unconsciously increased weight-bearing based on their pain level. This study shows that new, individual and possibly technology-assisted weight-bearing regimes are needed. The introduced measuring device is feasible to monitor and steer patient weight-bearing during future studies.

[Saw Injuries to the Hand - Epidemiological Aspects]. / Sägeverletzungen der Hand ­ epidemiologische Aspekte.

Background: No current studies regarding saw injuries have been published in German literature for quite some time. Despite awareness measures and safety instructions, saw accidents along with crush injuries are the most common causes of severe hand injuries. Approximately 12,000 circular saw injuries occur in Germany each year. Since professional providers have increased prices due to the rising energy costs and a wide range of different home appliance saws are available, increasing use has been made of portable circular saws in the do-it-yourself market sector. Patients and methods: At our hospital, we evaluated the data of 51 male patients with saw injuries. The present study investigated factors that may contribute to accidents involving saws. Results: 80 % of the accidents occurred at home, usually on weekends or after work. 51 % of the accidents happened while patients cut firewood. In 84 % of the cases, an electric table saw was used. The majority of severe hand injuries were sustained with lower priced saws. Injuries occurred most frequently between 11 a. m. and 2 p. m., primarily with injuries to bones, tendons, blood vessels and nerves. Replantable amputations or partial amputations occured rarely. In 37 % of the patients, anatomical reconstruction using osteosynthesis and/or microsurgical techniques was performed successfully. Conclusions: Saw injuries to the hand are sustained almost exclusively by men. Serious injuries from low-priced table saws and due to the lack of protective covering are predominant. Preventive measures and mandatory training could reduce the number of saw injuries in the years to come. The results obtained by us largely confirm the data from previous publications.

[Talus Fractures - an Update]. / Talusfrakturen ­ ein Update.

Background: Talus fractures are rare and often result from axial trauma. As most of the talus surface is covered by cartilage, the blood supply is limited. Thus talus fractures are seen as one of the most severe fractures and often lead to significant long-term complications. Several studies suggest that the initial fracture classification can lead to correct treatment and that this can influence the long-term outcome. The aim of the current study was to investigate the importance of the initial fracture classification in respect to the radiological outcome in a large patient cohort. Patients and Methods: Over a span of 12 years, 61 patients with talus fractures were treated at our institution. Overall 45 patients were available for a retrospective analysis. Correlation analysis was performed between the initial fracture severity and the radiological outcome. Results: The average follow-up was 17.3 months (range 6-68). Significant correlations were found between the Marti-Weber Classification and Bargon Score (rs = 0.78; p < 0.0001), as well as between the Hawkins Classification and the Bargon Score (rs = 0.80; p < 0.0001). Conclusions: Precise prediction of the expected radiological outcome of talar neck and body fractures is possible through the initial fracture classification alone. Computed tomography is the accepted standard to determine the exact diagnosis and extent of injury.

[Salvage procedure for painful proximalisation of the 1st metacarpal after trapeziectomy using the Mini TightRope®]. / Die Rettungsoperation mittels Mini TightRope® bei schmerzhafter Proximalisierung des 1. Mittelhandknochens nach Trapezektomie.

PURPOSE: This study analyses our results after revision surgery for failed trapezectomy and suspension arthroplasty with painful proximalisation of the 1(st) metacarpal using the Mini TightRope(®). PATIENTS AND METHODS: In a prospective observational study, 5 patients (4 women and 1 man) with an average age of 62 years were treated with the Mini TightRope(®) for revision of a failed Epping arthroplasty with painful proximalisation of the first ray. The mean time between initial surgery and revision was 23.1 (12.5-31.5) months; the mean follow-up was 25±7.7 (12-32) months. The pain level (visual analogue scale - VAS), pinch grip, and qDASH score were evaluated preoperatively and postoperatively. In addition, the Conolly score was used postoperatively. Directly after surgery and at the last follow-up exam, the degree of proximalisation of the first metacarpal was measured radiologically. RESULTS: At the last follow-up, there was significant mean pain relief during everyday stress, from 5.2 preoperatively to 1.6 (p<0.01) postoperatively, and a significant increase in pinch grip, from 0.5 kg to 3 kg (p<0.01). qDASH improved significantly, from 54 to 20 (p<0.001). The Conolly score showed 2 good and 3 fair results. Renewed proximalisation could not be entirely prevented, but was limited to an average of 2 mm. CONCLUSION: Mini TightRope(®) revision surgery after failed trapezectomy and suspension arthroplasty showes good results with significant pain reduction and gain of function. Renewed proximalisation of the first ray cannot be completely avoided.

Obesity does not affect the healing of femur fractures in mice.

Obesity is reported to be both protective and deleterious to bone. Lipotoxicity and inflammation might be responsible for bone loss through inhibition of osteoblasts and activation of osteoclasts. However, little is known whether obesity affects the process of fracture healing. Therefore, we studied the effect of high fat diet-induced (HFD) obesity on callus formation and bone remodelling in a closed femur fracture model in mice. Thirty-one mice were fed a diet containing 60kJ% fat (HFD) for a total of 20 weeks before fracture and during the entire postoperative observation period. Control mice (n=31) received a standard diet containing 10kJ% fat. Healing was analyzed using micro-CT, biomechanical, histomorphometrical, immunohistochemical, serum and protein biochemical analysis at 2 and 4 weeks after fracture. HFD-fed mice showed a higher body weight and increased serum concentrations of leptin and interleukin-6 compared to controls. Within the callus tissue Western blot analyses revealed a higher expression of transcription factor peroxisome proliferator-activated receptor y (PPARy) and a reduced expression of runt-related transcription factor 2 (RUNX2) and bone morphogenetic protein (BMP)-4. However, obesity did not affect the expression of BMP-2 and did not influence the receptor activator of nuclear factor κB (RANK)/RANK ligand/osteoprotegerin (OPG) pathway during fracture healing. Although the bones of HFD-fed animals showed an increased number of adipocytes within the bone marrow, HFD did not increase callus adiposity. In addition, radiological and histomorphometric analysis could also not detect significant differences in bone formation between HFD-fed animals and controls. Accordingly, HFD did not affect bending stiffness after 2 and 4 weeks of healing. These findings indicate that obesity does not affect femur fracture healing in mice.

Fracture healing redefined.

It is well established that local mechanical conditions and interfragmentary movement are important factors for successful bone healing and may vary dramatically with patient fracture-load and activity. Up until now however it was technically impossible to use these key influence parameters in the aftercare treatment process of human lower extremity fractures. We propose a theory that with state of the art sensor technology these biomechanical influences can not only be monitored in vivo, but also used for individualized therapy protocols. Local measurement systems for fracture healing are available but remain research tools, due to various technical issues. To investigate the biomechanical influences on healing right away surrogate sensor tools are needed. Various gait characteristics have been proposed as surrogate measures. Currently available sensor tools could be modified with the appropriate support structure to allow such measurements continuously over the course of a fracture healing. Interdisciplinary work between clinicians, software engineers with computer and biomechanical simulations is needed. Through such a sensor system human boundary conditions for fracture healing could not only be defined for the first time, but also used for a unique, extendible aftercare system. With this tool critical healing situations would be detected much earlier and could be prevented with easy activity modifications, reducing patient and socioeconomic burden of disease. The hypothesis, necessary tools and support structures are presented.

[Purpura fulminans of the adult--a hematological emergency]. / Purpura fulminans des Erwachsenen--ein hämatologischer Notfall.

HISTORY AND CLINICAL FINDINGS: A 51-year-old female patient with history of longterm drug abuse, was admitted to our hospital with large, stocking-shaped areas of painful, non-displaceable confluent bruising reaching up to the groin. INVESTIGATIONS: The emergency laboratory tests showed leucopenia, thrombocytopenia and anemia as well as a distinct protein C deficiency. DIAGNOSIS, TREATMENT AND COURSE: Purpura fulminans was diagnosed and treated with an initial dose of protein C. The patient survived and the skin necrosis can be treated. CONCLUSION: Purpura fulminans is an internistic and dermatological emergency situation which can lead to shock through consumptive coagulopathy. The serious course of disease can be prevented by rapid treatment with protein C.

[The effects of tobacco smoke on alveolar macrophages - an in vivo mouse lung model for short-term smoking]. / Die Auswirkungen von Tabakrauch auf Alveolarmakrophagen - ein In-vivo-Kurzzeitrauchmodell zur Mauslunge.

BACKGROUND: The effect of cigarette smoke (CS) on the phagocytosis of alveolar macrophages is discussed controversially on the basis of in vitro experiments. In this short report we describe the in vivo observations that we have performed. METHODS: For this purpose mice were exposed to CS for three consecutive days. One day later the fluorescent microspheres were administered intratracheally and the lung surface was investigated using long-distance fluorescence microscopy. RESULTS: We found that the numbers of neutrophils which engulfed particles was increased in the CS group as compared to controls. The overall phagocytic activity was not significantly different after CS exposure. CONCLUSIONS: In conclusion the phagocytosis of alveolar macrophages and neutrophils after short time CS exposure was not affected. Further investigations will need to look for the effects of long-term CS exposure and the phagocytosis of living bacteria.

Solubilization of a growth hormone-specific receptor from rabbit liver.

Membrane preparations from rabbit liver, known to possess GH-specific binding sites, have been solubilized with Triton X-100 and the binding characteristics of [125I]-human GH (hGH) and [125I]-bovine GH (bGH) subsequently studied. Specific binding of the hGH and bGH by the solubilized preparation was demonstrated of bound and free hormone by either polyethylene glycol precipitation or by Sephadex G-100 chromatography. Binding of hGH was both rapid and reversible and was displaced only by other growth hormones (bovine and ovine) and not by lactogenic hormones (ovine and human prolactins, human placental lactogen). As shown by Scatchard analysis specific binding of [125I]-bGH exhibited a lower binding affinity and capacity than did [125I]-hGH. Overall, the characteristics of the binding reaction for hGH were not significantly different from those reported for the particulate membrane preparation. The solubilization process did not appear to alter the binding protein(s) therefore, and permits a further study of the isolation, purification and properties of the binding protein(s) itself.

The presence of lactogen but not growth hormone binding sites in the isolated rat hepatocyte.

The binding of 125I-labelled human growth hormone (hGH) and bovine growth hormone (bGH) has been studied in hepatocytes isolated from female rats by perfusion with collagenase in situ. The cells appeared to retain normal membrane function, in that amino acid ([14C]alpha-aminoisobutyric acid) transport was both saturable and temperature-dependent. Amino acid ([14C]leucine) incorporation into protein was also linear over 3 h and was inhibited by cycloheximide. Binding of 125I-labelled hGH was dependent on time, temperature, hepatocyte concentration and hGH concentration. At 22 degrees C, binding reached a steady-state after 2-5 h and had a half-life of dissociation of 2-3 h. Hormone specificity studies indicated that binding was specific for hormones with prolactin-like activity (hGH, prolactins) and not for growth hormones themselves (bGH). Scatchard analysis revealed a single class of binding site with a binding capacity of 26-74+/-3-73 fmol/10(6) cells and a binding affinity of 1-24 X 10(9)+/-0-17 X 10(9) (S.E.M.) 1/mol (n=10). There was a significant sex difference in binding (female greater than male) and binding was subject to marked regulation by oestrogens (stimulation of binding) and by androgens (inhibition). The lactogen-binding sites, therefore, were comparable in many respects to those previously reported in rat liver membranes. No distinct GH binding sites were demonstrable as shown by the lack of specific binding by 125I-labelled bGH, purified either by Sephadex chromatography or by binding to and elution from GH receptors in rabbit liver membranes. The value of receptor purification of tracer for use in hormone binding studies was indicated by a substantial lowering of non-specific binding.

Binding of human growth hormone to hepatic lactogenic binding sites: regulation by oestrogens and androgens.

The binding of 125I-labelled human growth hormone (HGH) to the 'lactogenic' binding sites of rat liver membranes has been shown to be highly dependent on the oestrogen and androgen status of the membranes has been shown to be highly dependent on the oestrogen and androgen status of the animal from which the membranes were prepared. Oestradiol treatment of either male or female rats induced a highly significant rise in HGH binding. The minimum effective dose used was 2-5 mug/day and the rise in HGH binding was apparent after 4 days of treatment. Folowing cessation of oestradiol treatment of male rats HGH binding declined with a half-time of approximately 9 days. In contrast to the stimulatory effect of oestrogen, treatment of female rats with testosterone propionate (minimum effective dose 100-200 mug/day) led to a marked reduction in HGH binding. The influence of both oestrogens and androgens was confirmed following the removal of endogenous sex steroids by adrenalectomy-ovariectomy of female rats and castration of male rats. Scratchard analysis showed that, with the possible exception of adrenalectomy-ovariectomy, all pharmacologically and physiologically induced changes in HGH specific binding reflected changes in binding site capacity; there were no changes in binding affinity. While earlier studies have indicated that the oestrogen effect is primarily indirect and is mediated by the pituitary gland, the mode of action of the androgens is currently unknown. The relatively slow response of HGH binding to hormonal changes would support an indirect action for both the sex steroids. The stimulatory effect of oestrogens and the inhibitory effect of androgens may provide an explanation for the marked sex difference in HGH binding to rat liver membranes.

Characterization of the binding of human growth hormone to microsomal membranes from rat liver.

The binding of 125I-labelled human growth hormone to the 100000g microsomal membrane fraction prepared from the livers of normal female rats was dependent on time, temperature, pH, membrane concentration and concentration of 125I-labelled human growth hormone. At 22 degrees C binding reached a steady state after 16h, with the mean maximal specific binding being 20% of the tracer initially added. Dissociation of 125I-labelled human growth hormone from the membranes, after addition of excess of unlabelled hormone, was relatively slow with a half-time greater than 24h. Only minor degradation of the 125I-labelled human growth hormone was observed during incubation with membranes for 16 or 25h at 22 degrees C. Similarly, no significant change in the ability of membranes to bind human growth hormone was evident after preincubation of the membranes for 16 or 25h. Specificity studies showed that up to 90% of the 125I-labelled human growth hormone bound could be displaced by 1 mug of unlabelled hormone. Ovine prolactin also showed considerable competition for the binding site. Non-primate growth-hormone preparations (ovine, bovine, porcine and rat) and non-related hormones (insulin, thyrotropin, lutropin and follitropin) all showed negligible competition. Scatchard analysis of the binding data was consistent with two classes of binding site with binding affinities of 0.64 X 10(10) +/- 0.2 X 10(10)M-1 and 0.03 X 10(10) +/- 0.007 X 10(10)M-1 and corresponding binding capacities of 98.4 +/- 10 fmol/mg of protein and 314.6 +/- 46.3 fmol/mg of protein. These studies provide data which, in general, are consistent with the criteria required for hormone-receptor interaction. However, proof of the thesis that the human-growth-hormone-binding sites in female rat liver represent physiological receptors must await the demonstration of a correlation between hormone binding and a biological response.