Combined Treatment with Host-Directed and Anticytomegaloviral Kinase Inhibitors: Mechanisms, Synergisms and Drug Resistance Barriers

Despite the availability of currently approved antiviral drugs, infections with human cytomegalovirus (HCMV) still cause clinically challenging, sometimes life-threatening situations. There is an urgent need for enhanced anti-HCMV drugs that offer improved efficacy, reduced dosages and options for long-term treatment without risk of the development of viral drug resistance. Recently, we reported the pronounced anti-HCMV efficacy of pharmacological inhibitors of cyclin-dependent kinases (CDKs), in particular, the potential of utilizing drug synergies upon combination treatment with inhibitors of host CDKs and the viral CDK-like kinase pUL97 (vCDK/pUL97). Here, we expand this finding by further assessing the in vitro synergistic antiviral interaction between vCDK and CDK inhibitors towards HCMV as well as non-human cytomegaloviruses. An extension of this synergy approach was achieved in vivo by using the recombinant MCMV-UL97/mouse model, confirming the high potential of combination treatment with the clinically approved vCDK inhibitor maribavir (MBV) and the developmental CDK7 inhibitor LDC4297. Moreover, mechanistic aspects of this synergistic drug combination were illustrated on the levels of intracellular viral protein transport and viral genome replication. The analysis of viral drug resistance did not reveal resistance formation in the case of MBV + LDC4297 combination treatment. Spanning various investigational levels, these new results strongly support our concept, employing the great potential of anti-HCMV synergistic drug treatment.

Prediction of Response to 177Lu-PSMA Therapy Based on Tumor-to-Kidney Ratio on Pretherapeutic PSMA PET/CT and Posttherapeutic Tumor-Dose Evaluation in mCRPC

The aim of this study was to analyze the absorbed dose of 177Lu-PSMA in osseous versus lymphatic metastases in patients with metastatic castration-resistant prostate cancer across therapy cycles and to relate those data to therapeutic success. In addition, pretherapeutic prostate-specific membrane antigen (PSMA) PET/CT was evaluated for its ability to predict response behavior. Methods: The study comprised 30 patients with metastatic castration-resistant prostate cancer, each receiving at least 3 cycles of 177Lu-PSMA therapy. Prostate-specific antigen (PSA) values between baseline and 6 wk after the third therapy cycle were used to classify the patients as responders (PSA decline ≥ 50%) or nonresponders (unchanged or increasing PSA level). Quantitative SPECT/CT images were acquired 24, 48, and 168 h after application of 177Lu-PSMA. The absorbed dose for tumor lesions was calculated with dosimetry software. From the pretherapeutic PET/CT scan, the tumor-to-kidney uptake ratio was determined for different SUVs. Results: Regardless of patient response, the kidneys received a mean dose of 0.55 ± 0.20 Gy/GBq per cycle. In the first therapy cycle, the lymph node lesions received a mean dose of 3.73 ± 1.65 Gy/GBq in responders and 1.86 ± 1.25 Gy/GBq in nonresponders (P < 0.01). For bone lesions, the respective mean doses were 3.47 ± 2.00 Gy/GBq and 1.48 ± 0.95 Gy/GBq (P < 0.01). When successive therapy cycles were compared, the mean dose was found to have been reduced from the first to the second cycle by 27% for lymph nodes and by 33% for bone lesions. A significant difference (P < 0.01) in the ratio of lymph node and bone lesion uptake to kidney uptake between responders and nonresponders could be deduced from the pretherapeutic PET/CT scan. Conclusion: Significantly higher doses were achieved for lymph node and bone lesions in responders. The highest absorbed dose, for both lymphatic and osseous lesions, was achieved in the first cycle, decreasing in the second therapy cycle thereafter despite unchanged therapy activities. It may be possible to estimate the response to therapy from the ratio of tumor uptake to kidney uptake obtained from the pretherapeutic PSMA PET/CT scans.

Autofluorescent Artemisinin-Benzimidazole Hybrids via Organo-Click Reaction: Study of Antiviral Properties and Mode of Action in Living Cells

Drug modification by a fluorescent label is a common tool for studying its mechanism of action with fluorescence microscopy techniques. However, the attachment of a fluorescent label can significantly alter the polarity, solubility, and biological activity of the investigated drug, and, as a result, the studied mechanism of action can be misrepresented. Therefore, developing efficient drugs, which are inherently fluorescent and can be tracked directly in the cell is highly favorable. Here an easy formation of fluorescent hybrid drugs is presented, generated by a combination of two readily available non-fluorescent pharmacophores via a non-cleavable linker using a Ramachary-Bressy-Wang organocatalyzed azide-carbonyl [3+2] cycloaddition (organo-click) reaction. All newly prepared fluorescent compounds showed strong anti-HCMV activity (EC50 down to 0.07±0.00 μM), thus presenting a very promising drug developmental basis compared to the approved drug ganciclovir (EC50 2.60±0.50 μM). Remarkably, in vitro fluorescent imaging investigation of new compounds revealed induced changes in mitochondrial structures, which is a phenotypical hallmark of antiviral activity. This approach opens up new vistas for the easy formation of potent fluorescent drugs from readily available non-fluorescent parent compounds and might facilitate insight into their mode of action in living cells, avoiding the requirement of linkage to external fluorescent markers.

Three-year outcomes following transcatheter tricuspid valve edge-to-edge repair

Background

Tricuspid regurgitation (TR) has long been neglected due to limited therapeutic options. Within the past five years, transcatheter tricuspid valve edge-to-edge repair (T-TEER) has become a valuable tool in the treatment of TR besides diuretic medical therapy and valve surgery. Owing its novelty, data on long-term survival after T-TEER for relevant TR are sparse. Beyond that, there is uncertainty on the impact of TR reduction on outcomes after successful T-TEER.

Purpose

This study sought to investigate long-term survival outcome after T-TEER for relevant symptomatic TR. We evaluated the impact of TR reduction on outcome in patients with successful T-TEER.

Methods

Consecutive patients who underwent successful isolated T-TEER for relevant TR from 2016 until 2022 at a high-volume university center were included in the study. Procedural success was defined as at least one degree TR reduction. Long-term survival endpoint was three-year all-cause mortality. Survival follow-up was completed via phone calls with the patients themselves, the next of kin, local practitioners and using the German national population registry. Post-procedural TR was assessed by interventionalist and echocardiographer at the end of the T-TEER procedure.

Results

A total of 244 patients who underwent successful T-TEER in the study period were included in the present analysis (mean age 77.7±8.7 years; 50.8% female). Patients were highly symptomatic as represented by New York Heart Association functional class ≥ III in 95.9% of cases. TR was 4+ in 128 patients (52.2%), 3+ in 106 patients (43.4%) and 2+ in 10 patients (6.1%). The etiology of TR was predominately functional (88.5%), while 5.4% presented with degenerative TR and 6.1% with TR of mixed etiology. Median time to last contact or death was 365 days (interquartile range 166–809 days). Three-year follow-up was available in 98% of eligible patients. T-TEER was performed using a mean number of 2.0±0.6 devices (Mitra-/TriClip 53%; PASCAL 47%). Post-procedural TR was 1+ in 126 patients (51.6%), 2+ in 101 patients (41.4%) and 3+ in 17 patients (7.0%). Survival rates at one, two and three years were 76%, 68% and 56%. Among patients with procedural success (at least 1° TR reduction), a higher degree in post-procedural TR was associated with a trend towards reduced postinterventional survival (Figure 1). The absolute degree of TR reduction did not impact survival rates in patients with procedural success (Figure 2).

Conclusion

T-TEER effectively reduces TR severity and shows high rates of procedural success. While the extent of TR reduction did not yield prognostic value in terms of long-term survival, the degree of post-procedural TR showed a trend regarding survival outcome. These results indicate that procedural techniques and strategies should be refined to achieve TR1+ at the end of the procedure.

Funding Acknowledgement

Type of funding sources: None.

Right ventricular reverse remodeling after mitral valve transcatheter edge-to-edge repair

Background

Right ventricular dysfunction (RVD) is an important predictor for outcome in patients undergoing transcatheter mitral or tricuspid valve edge-to-edge repair (M/T-TEER). Due to the unique anatomy and contraction pattern of the RV, three-dimensional echocardiography (3DE) has emerged as a valuable tool in the assessment of RV function. While 3DE data showed RV reverse remodeling (RVRR) following T-TEER, respective data are absent in the setting of M-TEER.

Purpose

We sought to assess RVRR after M-TEER using 3DE comparing baseline and follow-up RV measurements.

Methods

Patients undergoing M-TEER treatment for relevant MR between August 2016 and February 2021 with eligible transthoracic 3DE of the RV at baseline and follow-up were included in the study. 3DE comprised RV end-diastolic and end-systolic volumes (RVEDV3D, RVESV3D), total RV stroke volume (RVSV3D) and RV ejection fraction (RVEF3D). Further, RV length (RVL3D) as well as RV basal (RVbase3D) and mid-ventricular diameters (RVmid3D) were derived from 3DE. RVRR was assessed as change in the respective 3DE parameters of RV dimensions between baseline and follow-up.

Results

A total of 66 patients (45.5% female; age 78.5±8.2 years; EuroScore II 4.6±3.6%) were included in the study. From baseline to latest available follow-up (median interval 364 days, interquartile range 180–728 days), a significant reduction of RVEDV3D and RVESV3D was observed (RVEDV3D 140.2±50.2 ml to 128.1±46.1 ml, p&lt;0.01 and RVESV3D 93.1±37.8ml to 87.1±34.7ml, p=0.04). The decrease in 3D-derived linear RV dimensions primarily occurred in the septolateral direction, while RV length did not change significantly. The observed RVRR was associated with significant reduction of TR severity. Of note, patients with RVRR showed also left ventricular reverse remodeling (LVRR).

Conclusion

M-TEER is an effective treatment option for patients with MR which leads to LVRR and RVRR.

Funding Acknowledgement

Type of funding sources: None.

Cyclin-Dependent Kinases (CDKs) and the Human Cytomegalovirus-Encoded CDK Ortholog pUL97 Represent Highly Attractive Targets for Synergistic Drug Combinations

Human cytomegalovirus (HCMV) is a pathogenic human herpesvirus associated with serious, potentially life-threatening symptoms in the immunocompromised or immunonaïve host. The limitations encountered by antiviral therapy options currently available include a narrow panel of accessible targets, the induction of viral drug resistance as well as severe drug dosage-mediated side-effects. Improved drug-targeting strategies to resolve these issues are the focus of our investigations. In particular, pharmaceutical kinase inhibitors (PKIs), either directed to host kinases or directed to the viral protein kinase pUL97, have been considered to overcome these restrictions. Recently, we reported the identification of a synergistic combination of two PKIs directed to host cyclin-dependent kinase 7 (CDK7) and viral CDK ortholog pUL97. Here, we substantiate these findings with the following results: (i) true drug synergy was exhibited by various chemical classes of PKI pairs directed to pUL97 and CDK7; (ii) no putative amplification of cytotoxicity by these drug combinations was observed; (iii) a reduction in drug dosage levels for synergistic combinations was defined on a quantitative basis and compared to monotreatments; (iv) the quantities of target proteins CDK7 and pUL97 expressed in HCMV-infected cells were assessed by confocal imaging, indicating a strong down-modulation of CDK7 levels as a result of synergistic drug treatment; (v) the functional importance of these target kinases, both binding to cyclin H, was illustrated by assessing HCMV replication under the viral genomic deletion of ORF-UL97 or cellular cyclin knock-out; (vi) new combinations of HCMV-specific drug synergy were demonstrated for solely host-directed treatments using PKIs against CDK2, CDK7, CDK8 and/or CDK9 and (vii) a triple PKI combination provided further support for the synergy approach. With these combined findings, this study highlights the potential of therapeutic drug combinations of approved, developmental and preclinical PKIs for expanding future options for anti-HCMV therapy.

Development of a PROTAC-Based Targeting Strategy Provides a Mechanistically Unique Mode of Anti-Cytomegalovirus Activity

Human cytomegalovirus (HCMV) is a major pathogenic herpesvirus that is prevalent worldwide and it is associated with a variety of clinical symptoms. Current antiviral therapy options do not fully satisfy the medical needs; thus, improved drug classes and drug-targeting strategies are required. In particular, host-directed antivirals, including pharmaceutical kinase inhibitors, might help improve the drug qualities. Here, we focused on utilizing PROteolysis TArgeting Chimeras (PROTACs), i.e., hetero-bifunctional molecules containing two elements, namely a target-binding molecule and a proteolysis-inducing element. Specifically, a PROTAC that was based on a cyclin-dependent kinase (CDK) inhibitor, i.e., CDK9-directed PROTAC THAL-SNS032, was analyzed and proved to possess strong anti-HCMV AD169-GFP activity, with values of EC50 of 0.030 µM and CC50 of 0.175 µM (SI of 5.8). Comparing the effect of THAL-SNS032 with its non-PROTAC counterpart SNS032, data indicated a 3.7-fold stronger anti-HCMV efficacy. This antiviral activity, as illustrated for further clinically relevant strains of human and murine CMVs, coincided with the mid-nanomolar concentration range necessary for a drug-induced degradation of the primary (CDK9) and secondary targets (CDK1, CDK2, CDK7). In addition, further antiviral activities were demonstrated, such as the inhibition of SARS-CoV-2 replication, whereas other investigated human viruses (i.e., varicella zoster virus, adenovirus type 2, and Zika virus) were found insensitive. Combined, the antiviral quality of this approach is seen in its (i) mechanistic uniqueness; (ii) future options of combinatorial drug treatment; (iii) potential broad-spectrum activity; and (iv) applicability in clinically relevant antiviral models. These novel data are discussed in light of the current achievements of anti-HCMV drug development.

Impact of the cardio-hepatic syndrome on outcomes after transcatheter mitral valve edge-to-edge repair

Background

The prognostic value of impaired liver function in the presence of moderate-to-severe and severe mitral regurgitation (MR), also called cardio-hepatic syndrome (CHS), for outcomes in patients undergoing transcatheter edge-to-edge repair (TEER) has not been studied yet.

Purpose

In this work, we aimed at identifying the prognostic impact of the CHS on two-year all-cause mortality in patients undergoing TEER compared to established risk factors. Furthermore, we evaluated the change in hepatic function after TEER.

Methods

Hepatic function was assessed by laboratory parameters of liver function (bilirubin, gamma glutamyl transferase [GGT], alkaline phosphatase [AP], aspartate and alanine aminotransferase [AST and ALT]). We defined CHS as elevation of at least two out of three laboratory parameters of hepatic cholestasis (bilirubin, GGT, AP). The impact of CHS on two-year mortality was evaluated using a proportional hazards Cox model. The change in hepatic function after TEER was evaluated by repeat laboratory testing at follow-up.

Results

We included 1083 patients who underwent TEER for highly symptomatic primary or secondary MR at four high volume academic European centers between 2008 and 2019. In 66.4% of patients, we observed elevated levels of either bilirubin, GGT or AP. CHS was present in 23% of patients and showed strong association with a reduced two-year survival (52.9% vs. 87.0% in patients without CHS, p&lt;0.01). In a multivariate Cox regression model, CHS was identified as a strong and independent predictor of increased two-year mortality (hazard ratio 1.49, p=0.03). In patients with successful MR reduction ≤2+ (90.7% of patients), parameters of hepatic function significantly improved from baseline to follow-up (−0.2 mg/dl for bilirubin; −21 U/l for GGT, respectively, p&lt;0.01), while they did not in case of residual postprocedural MR &gt;2+.

Conclusions

CHS can be observed in up to 25% of patients undergoing TEER and is associated with impaired two-year survival rates. Successful TEER is associated with decreased levels of hepatic enzymes at follow-up evaluation.

Funding Acknowledgement

Type of funding sources: None. Cardio-hepatic syndrome TEER

Multicentre experience with the transcatheter valve repair system for tricuspid regurgitation

Background

Tricuspid regurgitation (TR) is associated with high morbidity and mortality, but many patients are ineligible for surgical treatment due to age and co-morbidities. As a consequence, transcatheter treatment techniques have evolved over the last years. Leaflet repair is one of the most commonly used techniques and has recently gained commercial approval for dedicated TR treatment. The device offers the possibility for independent leaflet grasping and a central spacer can bridge larger coaptation gaps. The hitherto evidence is mainly based on compassionate use data. This is the first report on commercial use in a multicenter study with a large patient cohort and long-term follow-up.

Purpose

To investigate safety and efficacy of the leaflet repair system in the treatment of TR in a commercial use setting.

Methods

We retrospectively collected clinical and imaging data from all consecutive patients undergoing leaflet repair for TR at four tertiary care centres. A core laboratory analysis of the echocardiographic data has been performed. Baseline, procedural and follow-up data has been included in the analysis.

Results

A total of 155 patients, treated between February 2019 and February 2021 has been included (mean age 77±8 years, 52% female). Mean STS score was 7.7±6.7%. TR was of functional etiology in the majority (82%) of patients and was severe or higher graded in 87% (mean EROA 68±47 mm2). Patients were highly symptomatic with exertional dyspnea NYHA functional class III/IV in 91%. Technical success was achieved in 97% and TR was successfully reduced to ≤2+ in 90% of patients (p&lt;0.001). Three cases of intra-procedural single-leaflet device attachment (SLDA) occurred, and there was one case of access site bleeding requiring emergency surgery. There were no other in-hospital adverse events. Follow-up was available for 120 patients (median follow-up 182, IQR 54–356 days). TR reduction was sustained in most patients with TR ≤2+ in 83% (p&lt;0.001). We found indications for right ventricular (RV) remodeling with a significant decrease of RV end-diastolic diameter (57±8 mm vs. 52±10 m, p&lt;0.001). Dimensions of the inferior vena cava decreased significantly as a sign of less congestion (27±8 mm vs. 23±7 mm, p=0.004). During the follow-up period, 15 patients (10%) died, of which 7 (5%) were of a cardiovascular cause. Symptomatic improvement was significant with 66% of patients in NYHA functional class I or II at follow-up (p&lt;0.001) and an improvement of the 6-meter walking distance (228±120 m vs. 276±121 m, p=0.001).

Conclusion

Transcatheter treatment of TR with the leaflet repair system is feasible and safe. According to our data, technical success rate is high and procedural complications are rare. Patients experienced significant symptomatic improvement at follow-up with echocardiographic sustained TR reduction. Furthermore, there are indications for RV remodeling and reduced congestion.

Funding Acknowledgement

Type of funding sources: None. Improving valve function and symptoms

Methionine oxidation of proteins analyzed by affinity capillary electrophoresis in presence of silver(I) and gold(III) ions

Oxidative damage of biopharmaceuticals during manufacturing and storage is a key concern throughout pharmaceutical development. However, few simple and robust analytical methods are available for the determination of oxidation sites. Here, the potential of affinity capillary electrophoresis (ACE) in the separation of proteins with oxidized methionine (Met) residues is shown. Silver(I) and gold(I) ions have the attribute to selectively form complexes with thioethers over sulfoxides. The addition of these ions to the BGE leads to a selective complexation of Met residues and, thus, to a change of charge allowing separation of species according to the different oxidation states of Met. The mechanisms of these interactions are discussed and binding constants for peptides containing Met with silver(I) are calculated. Additionally, the proposed method can be used as an indicator of oxidative stress in large proteins. The presented technique is easily accessible, economical, and has rapid analysis times, adding new approaches to the analytical toolbox of Met sulfoxide detection.

Did anomalous atmospheric circulation favor the spread of COVID-19 in Europe?

The current pandemic of coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is having negative health, social and economic consequences worldwide. In Europe, the pandemic started to develop strongly at the end of February and beginning of March 2020. Subsequently, it spread over the continent, with special virulence in northern Italy and inland Spain. In this study we show that an unusual persistent anticyclonic situation prevailing in southwestern Europe during February 2020 (i.e. anomalously strong positive phase of the North Atlantic and Arctic Oscillations) could have resulted in favorable conditions, e.g., in terms of air temperature and humidity among other factors, in Italy and Spain for a quicker spread of the virus compared with the rest of the European countries. It seems plausible that the strong atmospheric stability and associated dry conditions that dominated in these regions may have favored the virus propagation, both outdoors and especially indoors, by short-range droplet and aerosol (airborne) transmission, or/and by changing social contact patterns. Later recent atmospheric circulation conditions in Europe (July 2020) and the U.S. (October 2020) seem to support our hypothesis, although further research is needed in order to evaluate other confounding variables. Interestingly, the atmospheric conditions during the Spanish flu pandemic in 1918 seem to have resembled at some stage with the current COVID-19 pandemic.

Did anomalous atmospheric circulation favor the spread of COVID-19 in Europe?

The current pandemic of coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is having negative health, social and economic consequences worldwide. In Europe, the pandemic started to develop strongly at the end of February and beginning of March 2020. Subsequently, it spread over the continent, with special virulence in northern Italy and inland Spain. In this study we show that an unusual persistent anticyclonic situation prevailing in southwestern Europe during February 2020 (i.e. anomalously strong positive phase of the North Atlantic and Arctic Oscillations) could have resulted in favorable conditions, e.g., in terms of air temperature and humidity among other factors, in Italy and Spain for a quicker spread of the virus compared with the rest of the European countries. It seems plausible that the strong atmospheric stability and associated dry conditions that dominated in these regions may have favored the virus propagation, both outdoors and especially indoors, by short-range droplet and aerosol (airborne) transmission, or/and by changing social contact patterns. Later recent atmospheric circulation conditions in Europe (July 2020) and the U.S. (October 2020) seem to support our hypothesis, although further research is needed in order to evaluate other confounding variables. Interestingly, the atmospheric conditions during the Spanish flu pandemic in 1918 seem to have resembled at some stage with the current COVID-19 pandemic.

Combinatorial Drug Treatments Reveal Promising Anticytomegaloviral Profiles for Clinically Relevant Pharmaceutical Kinase Inhibitors (PKIs)

Human cytomegalovirus (HCMV) is a human pathogenic herpesvirus associated with a variety of clinical symptoms. Current antiviral therapy is not always effective, so that improved drug classes and drug-targeting strategies are needed. Particularly host-directed antivirals, including pharmaceutical kinase inhibitors (PKIs), may help to overcome problems of drug resistance. Here, we focused on utilizing a selection of clinically relevant PKIs and determined their anticytomegaloviral efficacies. Particularly, PKIs directed to host or viral cyclin-dependent kinases, i.e., abemaciclib, LDC4297 and maribavir, exerted promising profiles against human and murine cytomegaloviruses. The anti-HCMV in vitro activity of the approved anti-cancer drug abemaciclib was confirmed in vivo using our luciferase-based murine cytomegalovirus (MCMV) animal model in immunocompetent mice. To assess drug combinations, we applied the Bliss independence checkerboard and Loewe additivity fixed-dose assays in parallel. Results revealed that (i) both affirmative approaches provided valuable information on anti-CMV drug efficacies and interactions, (ii) the analyzed combinations comprised additive, synergistic or antagonistic drug interactions consistent with the drugs’ antiviral mode-of-action, (iii) the selected PKIs, especially LDC4297, showed promising inhibitory profiles, not only against HCMV but also other α-, β- and γ-herpesviruses, and specifically, (iv) the combination treatment with LDC4297 and maribavir revealed a strong synergism against HCMV, which might open doors towards novel clinical options in the near future. Taken together, this study highlights the potential of therapeutic drug combinations of current developmental/preclinical PKIs.

Target verification of artesunate-related antiviral drugs: Assessing the role of mitochondrial and regulatory proteins by click chemistry and fluorescence labeling

Human cytomegalovirus (HCMV) infection is associated with serious pathology such as transplant rejection or embryonic developmental defects. Antiviral treatment with currently available drugs targeting viral enzymes is often accompanied with severe side effects and the occurrence of drug-resistant viruses. For this reason, novel ways of anti-HCMV therapy focusing on so far unexploited small molecules, targets and mechanisms are intensively studied. Recently, we described the pronounced antiviral activity of the artesunate-related class of trioxane compounds, comprising NF-κB/signaling inhibitors like the trimeric derivative TF27, which proved to be highly active in a nanomolar range both in vitro and in vivo. Here, we extend this analysis by presenting further TF27/artesunate-derived antiviral compounds designed for their specific use in target verification by click chemistry applied in fluorescence labeling and tag affinity strategies. Our main findings are as follows: (i) compounds TF27, BG95, AC98 and AC173 exert strong inhibitory activity against HCMV replication in cultured primary human cells, (ii) autofluorescence activity could be quantitatively detected for BG95 and AC98, and confocal fluorescence imaging revealed accumulation in mitochondria, (iii) postulated cellular targets including mitochondrial proteins were down-regulated upon TF27 treatment, (iv) a click chemistry-based protocol of target enrichment was established, and (v) mass spectrometry-based proteomic analysis, using proteins from HCMV-infected fibroblasts covalently interacting with AC173, revealed a refined list of targets. Combined, data strongly suggest a complex mode of antiviral drug-target interaction of artesunate-related compounds, now highlighting potential roles of mitochondrial, NF-κB pathway proteins, exportins and possibly more. This strategy may further promote antiviral drug development on the basis of pharmacologically optimized trioxane derivatives.

The trimeric artesunate derivative TF27 exerts strong anti-cytomegaloviral efficacy: Focus on prophylactic efficacy and oral treatment of immunocompetent mice

Human cytomegalovirus (HCMV) causes serious and even life-threatening diseases, particularly upon congenital or post-transplant infection. Treatment of HCMV infections with currently available drugs targeting viral enzymes is often limited by severe side effects and the emergence of drug-resistant viruses. To avoid this problem, novel therapeutic options directed to host proteins involved in virus replication are being investigated. Recently, we described the pronounced antiherpesviral activity of the trimeric artesunate derivative TF27 at low nanomolar concentrations in vitro and in vivo. In the present study, we report first data on the prophylactic efficacy of TF27 against human and murine CMV and the oncogenic avian alphaherpesvirus Marek's disease virus (MDV). The main findings of this study are (i) a pronounced activity of the experimental drug TF27 against alpha- and betaherpesviruses in vitro upon prophylactic treatment and (ii) a therapeutic and prophylactic efficacy upon oral treatment in an immunocompetent mouse model. Moreover, our data highlight (iii) the tolerability of orally administered TF27 free of compound-associated adverse events and further confirm (iv) the suitability of cellular factors as primary antiviral targets. Thus, we provide evidence for therapeutic and prophylactic antiherpesviral efficacy of TF27 upon oral treatment in immunocompetent hosts and thereby underline its potential for future antiviral drug development.

Application of affinity capillary electrophoresis for charge heterogeneity profiling of biopharmaceuticals

Charge heterogeneity profiling is important for the quality control (QC) of biopharmaceuticals. Because of the increasing complexity of these therapeutic entities [1], the development of alternative analytical techniques is needed. In this work, flow-through partial-filling affinity capillary electrophoresis (FTPFACE) has been established as a method for the analysis of a mixture of two similar monoclonal antibodies (mAbs). The addition of a specific ligand results in the complexation of one mAb in the co-formulation, thus changing its migration time in the electric field. This allows the characterization of the charged variants of the non-shifted mAb without interferences. Adsorption of proteins to the inner capillary wall has been circumvented by rinsing with guanidine hydrochloride before each injection. The presented FTPFACE approach requires only very small amounts of ligands and provides complete comparability with a standard CZE of a single mAb.

Artesunate derivative TF27 inhibits replication and pathogenesis of an oncogenic avian alphaherpesvirus

Nucleoside analogues have been the cornerstone of clinical treatment of herpesvirus infections since the 1970s. However, severe side effects and emergence of drug resistant viruses raise the need for alternative treatment options. We recently investigated the broad and strong antiherpesviral activity of the optimized artesunate derivative TF27 in vitro. TF27 efficiently inhibited replication of the highly oncogenic Marek's disease virus (MDV), a virus that infects chickens, causes deadly lymphomas and threatens poultry populations worldwide. In this study, we used this natural virus-host model for herpesvirus-induced cancer by infecting chickens with MDV, and evaluated the protective efficacy of TF27 and the nucleoside analogue valganciclovir (VGCV) on virus replication and tumorigenesis. We could demonstrate that both drugs reduced viral load in the blood and prevented tumor development in a large portion of the animals. Antiviral treatment also had a positive impact on body weight gain, while no negative compound-associated side effects were observed. This research provides the first evidence that the artesunate derivative TF27 and VGCV can be used in avian species and that they inhibit MDV replication and tumorigenesis. In addition, our study paves the way for promising approaches in future antiherpesviral drug development.

Biodistribution and radiation dosimetry of [18F]-JK-PSMA-7 as a novel prostate-specific membrane antigen-specific ligand for PET/CT imaging of prostate cancer

Aim

We investigated the whole-body distribution and the radiation dosimetry of [¹⁸F]-JK-PSMA-7, a novel ¹⁸F-labeled PSMA-ligand for PET/CT imaging of prostate cancer.

Methods

Ten patients with prostate cancer and biochemical recurrence or radiologic evidence of metastatic diseases were examined with 329–384 MBq (mean 359 ± 17 MBq) [¹⁸F]-JK-PSMA-7. Eight sequential positron emission tomography (PET) scans were acquired from 20 min to 3 h after injection with IRB approval. The kidneys, liver, lungs, spleen, and salivary glands were segmented into volumes of interest using the QDOSE dosimetry software suite (ABX-CRO, Germany). Absorbed and effective dose were calculated using the ICRP-endorsed IDAC 1.0 package. The absorbed dose of the salivary glands was determined using the spherical model of OLINDA 1.1. PSMA-positive lesions were evaluated separately. Quantitative assessment of the uptake in suspicious lesions was performed by analysis of maximum (max) and peak SUV values. The gluteus maximus muscle (SUV_mean) served as a reference region for the calculation of tumor-to-background ratios (TBR’s).

Results

Physiologic radiotracer accumulation was observed in the salivary and lacrimal glands, liver, spleen, and intestines, in a pattern resembling the distribution known from other PSMA-tracers with excretion via urinary and biliary pathways. The effective dose from [¹⁸F]-JK-PSMA-7 for the whole body was calculated to be 1.09E−02 mGy/MBq. The highest radiation dose was observed in the kidneys (1.76E−01 mGy/MBq), followed by liver (7.61E−02 mGy/MBq), salivary glands (4.68E−02 mGy/MBq), spleen (1.89E−02 mGy/MBq), and lungs (1.10E-2 mGy/MBq). No adverse effects of tracer injection were observed. Six out of ten patients were scored as PSMA-positive. A total of 18 suspicious lesions were analyzed, which included six bone lesions, nine lymph nodes, and three local lesions within the prostate fossa. The values for the SUV_max and SUV_peak in the PSMA-positive lesions increased until 60 min p.i. and remained at this intensity in the PET/CT scans until 140 min. In the period between 170 and 200 min after injection, a further significant increase in SUV_max and SUV_peak within the PSMA-positive lesions was observed.

Conclusions

The highest TBR of [¹⁸F]-JK-PSMA-7 was found 3 h after injection. From the kinetically collected data, it can be concluded that this trend may also continue in the further course. The start of the PET/CT acquisition should be chosen as late as possible. The high uptake in suspicious lesions in terms of absolute SUV_max and relative TBR values indicates potentially high sensitivity of the tracer for detection of prostate cancer manifestations.

4D-CT-based motion correction of PET images using 3D iterative deconvolution

Objectives

Positron emission tomography acquisition takes several minutes representing an image averaged over multiple breathing cycles. Therefore, in areas influenced by respiratory movement, PET-positive lesions occur larger, but less intensive than they actually are, resulting in false quantitative assessment. We developed a motion-correction algorithm based on 4D-CT without the need to adapt PET-acquisition.

Methods

The algorithm is based on a full 3D iterative Richardson-Lucy-Deconvolution using a point-spread-function constructed using the motion information obtained from the 4D-CT. In a motion phantom study (3 different hot spheres in background activity), optimal parameters for the algorithm in terms of number of iterations and start image were estimated. Finally, the correction method was applied to 3 patient data sets. In phantom and patient data sets lesions were delineated and compared between motion corrected and uncorrected images for activity uptake and volume.

Results

Phantom studies showed best results for motion correction after 6 deconvolution steps or higher. In phantom studies, lesion volume improved up to 23% for the largest, 43% for the medium and 49% for the smallest sphere due to the correction algorithm. In patient data the correction resulted in a significant reduction of the tumor volume up to 33.3 % and an increase of the maximum and mean uptake of the lesion up to 62.1 and 19.8 % respectively.

Conclusion

In conclusion, the proposed motion correction method showed good results in phantom data and a promising reduction of detected lesion volume and a consequently increasing activity uptake in three patients with lung lesions.

Primary cemented bipolar radial head prostheses for acute elbow injuries with comminuted radial head fractures: mid-term results of 37 patients

BACKGROUND

Radial head arthroplasty represents a widely accepted treatment for elbow injuries with non-reconstructible radial head fractures. The aim of this retrospective multicenter study was to assess mid-term results of patients with clearly defined elbow injuries including type III fractures of the radial head according to Mason's classification type III after primary arthroplasty using a cemented bipolar design.

MATERIALS AND METHODS

In 45 cases a primary cemented bipolar arthroplasty of the radial head was implanted for elbow injuries combined with an acute Mason type III radial head fracture. In all patients associated fractures were detected with preoperative CT scans and ligamentous injuries were evaluated and both were addressed intraoperatively based on a standardized algorithm. Patients with associated injuries other than coronoid fractures and collateral ligament tears were excluded from this study to obtain a more homogenous sample. Clinical and radiological assessment was performed on thirty-seven patients at an average of 5.6 years postoperatively.

RESULTS

DASH Score, functional rating index of Broberg and Morrey, Mayo Elbow Performance Score, and Mayo Modified Wrist Score confirmed good-to-excellent results in most of the patients. Compared to the unaffected arm range of motion and grip strength were slightly reduced. No elbow instability or loosening of the prosthesis, and minor degenerative changes were detected in a few cases.

CONCLUSION

Primary cemented bipolar arthroplasty for type III fractures according to Mason's classification in an elbow injury pattern only including associated coronoid fractures and/or ligamentous tears resulted in good-to-excellent mid-term results. These results suggest that primary bipolar radial head arthroplasty combined with distinct treatment of all associated injuries provides good functional outcomes concerning range of motion, elbow stability, and strength in this cohort. However, the associated injuries may influence clinical and radiological outcome and need to be detected, classified, and treated carefully.

Impact of different approaches to calculation of treatment activities on achieved doses in radioiodine therapy of benign thyroid diseases

Purpose

Radioiodine has been used for the treatment of benign thyroid diseases for over 70 years. However, internationally, there is no common standard for pretherapeutic dosimetry to optimally define the individual therapy activity. Here, we analyze how absorbed tissue doses are influenced by different approaches to pretherapeutic activity calculation of varying complexity.

Methods

Pretherapeutic determination of treatment activity was retrospectively recalculated in 666 patients who had undergone radioiodine therapy for benign thyroid diseases (Graves’ disease, non-toxic goiter, and uni- and multinodular goiter). Approaches considering none, some, or all of a set of individual factors, including target volume, maximum radioiodine uptake, and effective half-life, were applied. Assuming individually stable radioiodine kinetics, which had been monitored twice a day under therapy, hypothetically achieved tissue doses based on hypothetically administered activities resulting from the different methods of activity calculation were compared to intended target doses.

Results

The Marinelli formula yields the smallest deviations of hypothetically achieved doses from intended target doses. Approaches taking individual target volume into consideration perform better than fixed therapy activities, which lead to high variances in achieved doses and high deviations of hypothetically achieved doses from intended target doses.

Conclusion

Elaborate pretherapeutic dose planning, taking individual radioiodine uptake, half-life, and target volume into consideration, should be used whenever possible. The use of disease-specific fixed activities cannot be recommended. Deviations of achieved tissue doses from target doses can already be significantly lowered by application of volume-adapted treatment activities if more elaborate means are not available.

[Current overview of cartilage regeneration procedures]

BACKGROUND

Cartilage is an avascular, alymphatic and non-innervated tissue with limited intrinsic repair potential. The high prevalence of cartilage defects and their tremendous clinical importance are a challenge for all treating physicians.

AIM

This article provides the reader with an overview about current cartilage treatment options and their clinical outcome.

METHODS

Microfracture is still considered the gold standard in the treatment of small cartilage lesions. Small osteochondral defects can be effectively treated with the autologous osteochondral transplantation system. Larger cartilage defects are successfully treated by autologous membrane-induced chondrogenesis (AMIC) or by membrane-assisted autologous chondrocyte implantation (MACI).

CONCLUSION

Despite limitations of current cartilage repair strategies, such procedures can result in short- and mid-term clinical improvement of the patients. Further developments and clinical studies are necessary to improve the long-term outcome following cartilage repair.

The challenge of Monteggia-like lesions of the elbow

Aims

The aim of this retrospective multicentre study was to evaluate mid-term results of the operative treatment of Monteggia-like lesions and to determine the prognostic factors that influence the clinical and radiological outcome.

Patients and Methods

A total of 46 patients (27 women and 19 men), with a mean age of 57.7 years (18 to 84) who had sustained a Monteggia-like lesion were followed up clinically and radiologically after surgical treatment. The Mayo Modified Wrist Score (MMWS), Mayo Elbow Performance Score (MEPS), Broberg and Morrey Score, and Disabilities of the Arm, Shoulder and Hand (DASH) score were used for evaluation at a mean of 65 months (27 to 111) postoperatively. All ulnar fractures were stabilized using a proximally contoured or precontoured locking compression plate. Mason type I fractures of the radial head were treated conservatively, type II fractures were treated with reconstruction, and type III fractures with arthroplasty. All Morrey type II and III fractures of the coronoid process was stabilized using lag screws.

Results

Good results were found for the MMWS, with a mean of 88.4 (40 to 100). There were 29 excellent results (63%), nine good (20%), seven satisfactory (15%), and one poor (2%). Excellent results were obtained for the MEPS, with a mean of 90.7 (70 to 100): 31 excellent results (68%), 13 good (28%), and two fair (4%). Good results were also found for the functional rating index of Broberg and Morrey, with a mean score of 86.6 (57 to 100). There were 16 excellent results (35%), 22 good (48%), six fair (13%), and two poor (4%). The mean DASH score was 15.1 (0 to 55.8). Two patients had delayed wound healing; four patients had nonunion requiring bone grafting. One patient had asymptomatic loosening of the radial head prosthesis.

Conclusion

Monteggia-like lesions are rare. With correct identification, classification, and understanding using CT scans followed by appropriate surgical treatment that addresses all components of the injury, good to excellent mid-term results can be achieved. Cite this article: Bone Joint J 2018;100-B:212–18.

Hyperbaric oxygen therapy improves angiogenesis and bone formation in critical sized diaphyseal defects

Besides the use of autologous bone grafting several osteoconductive and osteoinductive methods have been reported to improve bone healing. However, persistent non-union occurs in a considerable number of cases and compromised angiogenesis is suspected to impede bone regeneration. Hyperbaric oxygen therapy (HBO) improves angiogenesis. This study evaluates the effects of HBO on bone defects treated with autologous bone grafting in a bone defect model in rabbits. Twenty-four New-Zealand White Rabbits were subjected to a unilateral critical sized diaphyseal radius bone defect and treated with autologous cancellous bone transplantation. The study groups were exposed to an additional HBO treatment regimen. Bone regeneration was evaluated radiologically and histologically at 3 and 6 weeks, angiogenesis was assessed by immunohistochemistry at three and six weeks. The additional administration of HBO resulted in a significantly increased new bone formation and angiogenesis compared to the sole treatment with autologous bone grafting. These results were apparent after three and six weeks of treatment. The addition of HBO therapy to autologous bone grafts leads to significantly improved bone regeneration. The increase in angiogenesis observed could play a crucial role for the results observed.

The effect of bone marrow concentrate and hyperbaric oxygen therapy on bone repair

Neoangiogenesis represents an essential part of bone regeneration. Therefore the improvement of neovascularization is the subject of various research approaches. In addition autologous mesenchymal stem cells concentrate in combination with bone substitute materials have been shown to support bone regeneration. In a rabbit model we examined the proposed synergistic effect of hyperbaric oxygen therapy (HBOT) and bone marrow concentrate (BMC) with porous calcium phosphate granules (CPG) on neoangiogenesis and osseous consolidation of a critical- size defect. The animal groups treated with HBOT showed a significantly higher microvessel density (MVD) by immunhistochemistry. Furthermore HBOT groups presented a significantly larger amount of new bone formation histomorphometrically as well as radiologically. We conclude that the increase in perfusion as a result of increased angiogenesis may play a key role in the effects of HBOT and consequently promotes bone healing.

The treatment of the acute Essex-Lopresti injury

The Essex-Lopresti injury (ELI) of the forearm is a rare and serious condition which is often overlooked, leading to a poor outcome. The purpose of this retrospective case study was to establish whether early surgery can give good medium-term results. From a group of 295 patients with a fracture of the radial head, 12 patients were diagnosed with ELI on MRI which confirmed injury to the interosseous membrane (IOM) and ligament (IOL). They were treated by reduction and temporary Kirschner (K)-wire stabilisation of the distal radioulnar joint (DRUJ). In addition, eight patients had a radial head replacement, and two a radial head reconstruction. All patients were examined clinically and radiologically 59 months (25 to 90) after surgery when the mean Mayo Modified Wrist Score (MMWS) was 88.4 (78 to 94), the mean Mayo Elbow Performance Scores (MEPS) 86.7 (77 to 95) and the mean disabilities of arm, shoulder and hand (DASH) score 20.5 (16 to 31): all of these indicate a good outcome. In case of a high index of suspicion for ELI in patients with a radial head fracture, we recommend the following: confirmation of IOM and IOL injury with an early MRI scan; early surgery with reduction and temporary K-wire stabilisation of the DRUJ; preservation of the radial head if at all possible or replacement if not, and functional bracing in supination. This will increase the prospect of a good result, and avoid the complications of a missed diagnosis and the difficulties of late treatment.

Isolierte, unilaterale Parese des N. phrenicus nach Pneumonie und Pleuritis

Unilateral diaphragmatic paralysis has many causes. Tumor and trauma are the two most frequent identifiable causes. Infectious processes involving the lung and/or mediastinum may result in temporary or permanent diaphragmatic paralysis. We report the case of an 81-year old man who suffered from right-sided pneumonia followed by a period of several months with exertion dyspnea. Radiological examinations showed an elevated right diaphragm, abnormal restrictive lung function, and impaired diaphragmatic muscle strength. The neurophysiological studies provided evidence of a partial phrenic nerve lesion. We discuss the differential diagnosis of isolated phrenic nerve lesions with particular regard to infections.

[Early corrective osteotomy after secondary displaced distal radius fractures in children]

Secondary fracture displacement before osseous consolidation of distal radius fractures in children occasionally leads to restricted forearm rotation. So far, there is no consistent treatment recommendation to correct this complication. We report on 5 children with an age of 8-13 years (mean age 12.3 years, 4 boys, 1 girl) with secondary displaced distal radius fractures and high functional deficits in forearm rotation (mean ROM for pro-/supination 70-0-30°) after osseous consolidation. We performed corrective osteotomies of the distal radius using a palmar approach after a mean of 38 days. Stabilisation was achieved with a fixed-angle plate system. At the final follow-up examination (mean 9 months) the forearm rotation was normal. No complications were observed. We consider corrective osteotomies of the distal radius in children with deficits of forearm rotation to be a possible strategy. Early corrective osteotomies can lead to a predictable increase of function through reestablishing normal articulation.

The early phase influence of bone marrow concentrate on metaphyseal bone healing

Bone marrow concentrate (BMC) contains high densities of progenitor cells. Therefore, in critical size defects BMC may have the potency to support bone healing. The aim of this study was to investigate the effect of BMC in combination with calcium phosphate granules (CPG) on bone defect healing in a metaphyseal long bone defect in mini-pigs. A metaphyseal critical-size bone defect at the proximal tibia of 24 mini-pigs was filled with CPG combined with BMC, CPG solely (control group) or with an autograft. Radiological and histomorphometrical evaluations after 6 weeks (42 days) showed significantly more bone formation in the BMC group in the central area of the defect zone and the cortical defect zone compared to the CPG group. At the same time the resorption rate of CPG increased significantly in the BMC group. Nevertheless, compared to the BMC group the autograft group showed a significantly higher new bone formation radiologically and histomorphometrically. In BMC the count of mononuclear cells was significantly higher compared to the bone marrow aspirate (3.5-fold). The mesenchymal progenitor cell characteristics of the cells in BMC were confirmed by flow cytometry. Cells from BMC created significantly larger colonies of alkaline phosphatase-positive colony forming units (CFU-ALP) (4.4-fold) compared to cells from bone marrow aspirate. Nevertheless, even in the BMC group complete osseous bridging was only detectable in isolated instances of the bone defects. Within the limitations of this study the BMC+CPG composite promotes bone regeneration in the early phase of bone healing significantly better than the isolated application of CPG. However, the addition of BMC does not lead to a solid fusion of the defect in the early phase of bone healing an still does not represent an equal alternative to autologous bone.

Global dimming and brightening - evidence and agricultural implications

Abstract

There is growing observational evidence that the level of sunlight received at the Earth's surface is not stable over the years but undergoes substantial decadal changes. These changes, known popularly as global dimming and brightening, are related to anthropogenic air pollution, as well as changes for cloudiness. Here, we summarize the evidence and discuss the implications of these variations in biospheric growth in general and agricultural applications in particular. Emphasis is placed on implications for forest canopies, grassland and agricultural crop production. Yet not only the total amount of sunlight that the biosphere receives is important but also the relative portion of the direct and diffuse light. Increasing air pollution and cloudiness can alter this partitioning towards a higher relative portion of diffuse light, in addition to a reduction in the total amount of sunlight. This diffuse light can enhance photosynthesis, particularly in tall and dense vegetation canopies, as it is distributed more effectively within the canopy compared with direct solar radiation, which is only accessible to the outermost (sunlit) layers. Here, we conclude that the growth of tall canopies such as forests or crop fields may be favoured under global dimming conditions owing to the enhanced diffuse light, despite the overall reduction in the total amount of sunlight. On the other hand, under the same dimming conditions, the yield of grassland, with its shallow open canopy, may be reduced, as it has little benefit from the enhanced diffuse fraction, while suffering from a loss in the total amount of sunlight for photosynthesis. Variations in solar radiation therefore may have largely varying effects on agricultural production depending on the structure of the crop canopy.

[Quality of documentation and care for victims of violence for the example of a trauma surgery emergency department in a major city]

BACKGROUND

People who have become victims of violence have manifold problems. Besides medical diagnostics and therapy, it is necessary to recognise the situation in which these patients have become such victims, to document the consequences of this violence for use in court and to offer further assistance. Victims of violence often contact primarily a trauma ambulance. The optimisation of the medical treatment of the victims is a relevant traumatological topic, which so far has received only very scant attention. Therefore the aim of this study was to evaluate the necessity for an interdisciplinary combination of treatments for the targeted treatment of these victims.

MATERIAL AND METHODS

Using a standardised data card a retrospective data analysis of all out-patients and all in-patients of a trauma centre with regard to the existence of a violent context was carried out for the year 2004. All such cases were included and the data were evaluated descriptively according to age, gender, information about the act of violence, consequences thereof, type and scope of the diagnostic findings, as well as inducements for further measures. In this context we differentiated between "domestic violence" and "public violence".

RESULTS

The data of 7132 patients were evaluated. Altogether 347 victims of violence were identified (among them 109 victims of "public violence", 59 victims of domestic violence, and 179 cases that could not be allocated clearly). This results in a quota of 4.9% of all patients treated. The average age of the victims was 30.6 years. It was striking that in many cases the anamnesis and documentation were rather fragmentary.

CONCLUSION

A very high percentage of victims of violence could be found among the patients needing traumatological treatment. With regard to the fragmentary care there is an enormous need for medical training and interdisciplinary treatment of victims of violence.

Fixed-angle plates in patella fractures - a pilot cadaver study

Objective

Modified anterior tension wiring with K-wires and cannulated lag screws with anterior tension wiring are currently the fixation of choice for patellar fractures. Failure of fixation, migration of the wires, postoperative pain and resulting revision surgery, however, are not uncommon. After preliminary biomechanical testing of a new fixed-angle plate system especially designed for fixation of patella fractures the aim of this study was to evaluate the surgical and anatomical feasibility of implanting such a plate-device at the human patella.

Methods

In six fresh unfixed female cadavers without history of previous fractures around the knee (average age 88.8 years) a bilateral fixed-angle plate fixation of the patella was carried out after previous placement of a transverse central osteotomy. Operative time, intra-operative problems, degree of retropatellar arthritis (following Outerbridge), quality of reduction and existence of any intraarticular screw placement have been raised. In addition, lateral and anteroposterior radiographs of all specimens were made.

Results

Due to the high average age of 88.8 years no patella showed an unimpaired retropatellar articular surface and all were severely osteoporotic, which made a secure fixation of the reduction forceps during surgery difficult. The operation time averaged 49 minutes (range: 36-65). Although in postoperative X-rays the fracture gap between the fragments was still visible, the analysis of the retropatellar surface showed no residual articular step or dehiscence > 0.5 mm. Also in a total of 24 inserted screws not one intraarticular malposition was found. No intraoperative complications were noticed.

Conclusions

Osteosynthesis of a medial third patella fracture with a bilateral fixed-angle plate-device is surgically and anatomically feasible without difficulties. Further studies have to depict whether the bilateral fixed-angle plate-osteosynthesis of the patella displays advantages over the established operative procedures.

The progress of early phase bone healing using porous granules produced from calcium phosphate cement

Objective

Bone grafting is a vital component in many surgical procedures to facilitate the repair of bone defects or fusions. Autologous bone has been the gold standard to date in spite of associated donor-site morbidity and the limited amount of available donor bone. The aim of this study was to investigate the progress of bone regeneration and material degradation of calcium phosphate granules (CPG) produced from a calcium phosphate self-setting cement powder compared to the use of autologous bone grafting in the treatment of "critical size defects" on load-bearing long bones of minipigs.

Methods

A critical size defect in the tibial metaphysis of 16 mini-pigs was filled either with autologous cancellous graft or with micro- and macroporous carbonated, apatic calcium phosphate granules (CPG) produced from a calcium phosphate self-setting cement powder. After 6 weeks, the specimens were assessed by X-ray and histological evaluation. The amount of new bone formation was analysed histomorphometrically.

Results

The semi-quantitative analysis of the radiological results showed a complete osseous bridging of the defect in three cases for the autograft group. In the same group five animals showed a beginning, but still incomplete bridging of the defect, whereas in the CPG group just two animals developed this. All other animals of the CPG group showed only a still discontinuous new bone formation. Altogether, radiologically a better osseous bridging was observed in the autograft group compared to the CPG group.

Histomorphometrical analysis after six weeks of healing revealed that the area of new bone was significantly greater in the autograft group concerning the central area of the defect zone (p < 0.001) as well as the cortical defect zone (p < 0.002). All defects showed new bone formation, but only in the autograft group defects regenerated entirely

Conclusions

Within the limits of the present study it could be demonstrated that autologous cancellous grafts lead to a significantly better bone regeneration compared to the application of calcium phosphate granules (CPG) produced from a calcium phosphate self-setting cement powder after 6 weeks. In the early phase of bone-healing, the sole application of CPG appears to be inferior to the autologous cancellous grafts in an in vivo critical size defect on load-bearing long bones of mini-pigs.

[Radial nerve palsy associated with humeral shaft fractures - early exploration or expectant procedure? An analysis concerning current strategies of treatment]

BACKGROUND

With a prevalence from 11.8 to 18% no fracture is as often associated with nerve damage as the humeral shaft fracture. Whether the radial nerve should be surgically explored in association with a palsy in humeral shaft fractures in order to exclude an interposition or discontinuity is being discussed controversially. The aim of this study was to assess the strategies for primary care of radial nerve palsies associated with humeral shaft fractures in Germany.

MATERIAL AND METHODS

In a standardised survey 495 traumatological and 134 neurosurgical clinics were interviewed regarding the treatment of primary radial nerve palsies after humeral shaft fractures. The distribution of the survey included all level-one trauma centres. Statistics were based on the supply strategies, the number of observed contusions, discontinuities and inter-position of the N. radialis in the fracture gap. Moreover, the results were recorded after primary neurorrhaphy.

RESULTS

The evaluable response rate to the questionnaire was 56% (university hospitals 77%, level-one trauma centres 63%, level-two trauma centres 70%, level-three trauma centres 44%). 6097 humeral shaft fractures have been treated per year, the incidence of primary radial nerve palsy was 8.6%. Regarding the management strategies, 59% of the hospitals advocated exploration of the nerve, while 25% reported that the decision depends on the individual case. 16% reject the exploration in case of a primary nerve palsy. In the case of an exploration, contusions (74%) of the nerve were largely seen, followed by nerve interpositions in the fracture gap (19%) and discontinuity (7%). In the case of neurorrhaphy, a partial or complete remission was found in 87% of cases.

DISCUSSION

Although a primary expectant procedure is recommended in the literature due to the high spontaneous remission rate of 90%, an early exploration of the nerve is often preferred in clinical practice. In these cases, the use of an interlocking intramedullary nail as a minimally invasive treatment option does not appear useful due to the direct exposure of the fracture zone and the radial nerve. Interestingly, the feared discontinuity occurs rarely. The impact of nerve interposition in the fracture gap without surgical exploration remains unclear due to the lack of visibility.

CONCLUSION

There is no consensus concerning the treatment of radial nerve palsies after humeral shaft fractures in Germany. Discontinuities are rare, the rate of spontaneous recoveries is high. Whether and when an exploration of the radial nerve is obligatory in primary radial palsy remains unclear and should be clarified by prospective randomised trials.

Combined use of platelet-rich plasma and autologous bone grafts in the treatment of long bone defects in mini-pigs

The use of platelet-rich plasma (PRP) for improving of bone defect healing is discussed controversially. The aim of this study was to assess the effect of PRP in combination with autologous cancellous graft on bone defect healing in a critical metaphyseal long bone defect. A critical size defect in the tibial metaphysis of 16 mini-pigs was filled either with autologous cancellous graft as control group or with autologous cancellous graft combined with autologous PRP. Compared to native blood platelets were enriched about 4.9-fold in the PRP. After 6 weeks, the specimens were assessed by X-ray and histological evaluation. Histomorphometrical analysis revealed that the area of new bone was significantly higher in the PRP group concerning the central area of the defect zone (p<0.02) as well as the cortical defect zone (p<0.01). All defects showed substantial new bone formation, but only defects of the PRP group regenerated entirely. The PRP group was superior to the control group even in the semi-quantitative assessment of the osseous bridging in both observed areas of the defect. Within the limits of the present study it could be demonstrated that PRP combined with autologous cancellous graft leads to a significantly better bone regeneration compared to isolated application of autologous cancellous graft in an in vivo critical size defect on load-bearing long bones of mini-pigs.

[The operative treatment of the degenerative rupture of the anterior tibialis tendon]

AIM

A degenerative tear of the anterior tibial tendon is a rare event compared to other tendons. The purpose of this study was to evaluate the functional results after surgical refixation.

METHOD

In a retrospective study, we report the functional outcome of five consecutive operatively treated patients suffering from a tear close to the insertion site of the anterior tibial tendon. All patients were assessed postoperatively, the AOFAS and Richter scores were obtained and the range of motion in the ankle joint was evaluated.

RESULTS

Preoperatively all patients presented with a significant walking impairment due to a reduced active dorsiflexion, so the decision for surgical refixation was made. In all cases an MRI scan was performed preoperatively. Postoperative immobilisation without weight-bearing was done for six weeks. All patients returned to their former activity level, were satisfied with the postoperative result and had a normal gait in the follow-up examination. The range of motion was equal on both sides, the median AOFAS score was 86 and the median Richter score was 90 out of 100. There were no postoperative complications.

DISCUSSION

Untreated tears of the anterior tibial tendon lead to significant impairment of the ankle joint and deformities of the foot. There is no consensus about the treatment with recommendations for operative and non-operative treatment. Various surgical procedures have been described. The surgical reconstruction of the tendon leads to a restored function of the ankle joint and allows a normal gait and is therefore desirable. Due to the loss of function and the good results after surgical treatment in our study, the non-operative treatment is not advisable.

CONCLUSION

Surgical repair of degenerative tears of the anterior tibial tendon leads to very good functional results and high patient satisfaction.

Functional results and complications following locking palmar plating on the distal radius: a retrospective study

This retrospective study investigates the radiological and the functional results as well as complications following locking palmar plating on the distal radius. Eighty-nine adult patients with a dorsally displaced distal radius fracture were treated using a locking palmar plate at our clinic over a period of 25 months. The radiological and functional results as well as the DASH score were recorded for 77 out of 89 patients in the routine final examinations conducted on average 12 months later. The radiological examinations showed a relevant shortening of the radius among five patients. A dorsal angulation of more than 20 degrees as well as a radial inclination of less than 10 degrees was observed in 11 patients. Most of the patients showed good to excellent functional and radiological results as well as good results on the DASH score. A3 fractures in elderly patients and the majority of C1 and C2 fractures can be safely treated with locking palmar plating.

[Functional and subjective results following subtalar dislocations]

BACKGROUND

The objective of our study is to evaluate the functional and subjective results following subtalar dislocations without any associated bone injuries and to examine whether the direction of dislocation has any effect on the post-traumatic results.

METHODS

Over the period from February 1998 to May 2006, 56 patients with a subtalar dislocation were enrolled in the study. A subtalar dislocation without any associated bone injuries was only present in 13 patients. Follow-up examination after an average of 39.8 months was performed using the AOFAS Ankle-Hindfoot scale. The adapted classification developed by Altman was used to assess the post-traumatic degree of arthrosis radiologically.

RESULTS

The average AOFAS score was 81, with good results in 11 patients and satisfactory results in 2 patients. The range of motion (ROM) for the ankle-hindfoot joint was 39.2 degrees .

CONCLUSION

Despite the severity of the injury, the functional and subjective results of subtalar dislocations without any bone injuries are good. Generally, no early post-traumatic arthrosis occurs if there are no associated bone injuries. No differences were established between medial and lateral subtalar dislocations.