Patient-oriented and performance-based outcomes after knee autologous chondrocyte implantation: a timeline for the first year of recovery

It is well established that autologous chondrocyte implantation (ACI) can require extended recovery postoperatively; however, little information exists to provide clinicians and patients with a timeline for anticipated function during the first year after ACI. Objective: To document the recovery of functional performance of activities of daily living after ACI. Patients: ACI patients (n = 48, 29 male 35.1 ± 8.0 y). Intervention: All patients completed functional tests (weight-bearing squat, walk-across, sit-to-stand, step-up/over, and forward lunge) using the NeuroCom long force plate (Clackamas, OR) and completed patient-reported outcome measures (International Knee Documentation Committee Subjective Knee Evaluation Form, Lysholm, Western Ontario and McMaster Osteoarthritis Index WOMAC, and 36-Item Short-Form Health Survey) preoperatively and 3, 6, and 12 mo postoperatively. Main Outcome Measures: A covariance pattern model was used to compare performance and self-reported outcome across time and provide a timeline for functional recovery after ACI. Results: Participants demonstrated significant improvement in walk-across stride length from baseline (42.0% ± 8.9% height) at 6 (46.8% ± 8.1%) and 12 mo (46.6% ± 7.6%). Weight bearing on the involved limb during squatting at 30°, 60°, and 90° was significantly less at 3 mo than presurgery. Step-up/over time was significantly slower at 3 mo (1.67 ± 0.69 s) than at baseline (1.49 ± 0.33 s), 6 mo (1.51 ± 0.36 s), and 12 mo (1.40 ± 0.26 s). Step-up/over lift-up index was increased from baseline (41.0% ± 11.3% body weight BW) at 3 (45.0% ± 11.7% BW), 6 (47.0% ± 11.3% BW), and 12 mo (47.3% ± 11.6% BW). Forward-lunge time was decreased at 3 mo (1.51 ± 0.44 s) compared with baseline (1.39 ± 0.43 s), 6 mo (1.32 ± 0.05 s), and 12 mo (1.27 ± 0.06). Similarly, forward-lunge impact force was decreased at 3 mo (22.2% ± 1.4% BW) compared with baseline (25.4% ± 1.5% BW). The WOMAC demonstrated significant improvements at 3 mo. All patient-reported outcomes were improved from baseline at 6 and 12 mo postsurgery. Conclusions: Patients' perceptions of improvements may outpace physical changes in function. Decreased function for at least the first 3 mo after ACI should be anticipated, and improvement in performance of tasks requiring weight-bearing knee flexion, such as squatting, going down stairs, or lunging, may not occur for a year or more after surgery

Optimized polymer-based glucose release in microtiter plates for small-scale E. coli fed-batch cultivations

Background: Small-scale cultivation vessels, which allow fed-batch operation mode, become more and more important for fast and reliable early process development. Recently, the polymer-based feeding system was introduced to allow fed-batch conditions in microtiter plates. Maximum glucose release rates of 0.35 mg/h per well (48-well-plate) at 37 °C can be achieved with these plates, depending on the media properties. The fed-batch cultivation of fluorescent protein-expressing E. coli at oxygen transfer rate levels of 5 mmol/L/h proved to be superior compared to simple batch cultivations. However, literature suggests that higher glucose release rates than achieved with the currently available fed-batch microtiter plate are beneficial, especially for fast-growing microorganisms. During the fed-batch phase of the cultivation, a resulting oxygen transfer rate level of 28 mmol/L/h should be achieved. Results: Customization of the polymer matrix enabled a considerable increase in the glucose release rate of more than 250% to up to 0.90 mg/h per well. Therefore, the molecular weight of the prepolymer and the addition of a hydrophilic PDMS-PEG copolymer allowed for the individual adjustment of a targeted glucose release rate. The newly developed polymer matrix was additionally invariant to medium properties like the osmotic concentration or the pH-value. The glucose release rate of the optimized matrix was constant in various synthetic and complex media. Fed-batch cultivations of E. coli in microtiter plates with the optimized matrix revealed elevated oxygen transfer rates during the fed-batch phase of approximately 28 mmol/L/h. However, these increased glucose release rates resulted in a prolonged initial batch phase and oxygen limitations. The newly developed polymer-based feeding system provides options to manufacture individual feed rates in a range from 0.24-0.90 mg/h per well. Conclusions: The optimized polymer-based fed-batch microtiter plate allows higher reproducibility of fed-batch experiments since cultivation media properties have almost no influence on the release rate. The adjustment of individual feeding rates in a wide range supports the early process development for slow, average and fast-growing microorganisms in microtiter plates. The study underlines the importance of a detailed understanding of the metabolic behavior (through online monitoring techniques) to identify optimal feed rates. © 2020 The Author(s)

Late Removal of Titanium Hardware from the Elbow is Problematic

A retrospective review of 21 patients that underwent bone screw removal from the elbow was studied in relation to the type of metal, duration of implantation, and the location of the screws about the elbow. Screw failure during extraction was the dependent variable. Five of 21 patients experienced hardware failure during extraction. Fourteen patients had titanium alloy implants. In four cases, titanium screws broke during extraction. Compared to stainless steel, titanium screw failure during removal was not statistically significant (P = 0.61). Screw removal 12 months after surgery was more likely to result in broken, retained screws in general (P = 0.046) and specifically for titanium alloy (P = 0.003). Bone screws removed from the distal humerus or proximal ulna had an equal chance of fracturing (P = 0.28). There appears to be a time-related association of titanium alloy bone screw failure during hardware removal cases from the elbow. This may be explained by titanium\u27s properties and osseointegration

Charakterisierung atherosklerotischer Plaque-Ablagerungen mittels FTIR- und Raman-Mikrospektroskopie

Atherosklerotische Plaques bestehen hauptsächlich aus Cholesterolestern, Cholesterol, Phospholipiden, Triglyzeriden, Proteoglykanen und kristallinem Kalzium. Histopathologische Untersuchungen zeigen, dass die Zusammensetzung je nach Plaque-Art sehr unterschiedlich sein kann. Eine Strukturanalyse mit Erfassung der molekularen Plaquezusammensetzung kann durch die Kombination von klassisch-analytischen Spektroskopie-Methoden mit der konventionellen Mikroskopie erreicht werden und ist Ziel dieser Arbeit. Fünf männliche New Zealand White Kaninchen erhielten über 9 Wochen eine 0,5%ige cholesterinreiche Diät. Sondenspektroskopisch definierte lipidreiche Areale der Kaninchenaorten wurden nach durchgeführter Perfusionsfixierung entnommen und zur Herstellung von Kryostat- und Paraffinpräparaten genutzt. Für die Lipid-Färbung wurde Sudanschwarz, für die Übersichtsfärbung Hämatoxylin-Eosin genutzt. Die morphometrischen Messungen fanden an Elastica van Gieson gefärbten Präparaten statt, für die FTIR-(Fourier- Transform-Infrarot-) und Raman-Mikrospektroskopie dienten die reinen Kryostatpräparate. Die erhaltenen Spektralinformationen der Übersichts- und Detailaufnahmen wurden mithilfe bildgebender Software im Rahmen einer multivariaten Datenanalyse bearbeitet und als Falschfarben-Bilder dargestellt. Die IR-spektroskopische Bildgebung erlaubte eine Differenzierung zwischen lipid- und proteinhaltigen Komponenten sowie eine quantitative Ermittlung des Lipid-Protein-Verhältnisses. Cholesterin, Cholesterinester, Phospholipide/ Triglyzeride und verschiedene Proteinkomponenten konnten anhand der Raman-Mikrospektroskopie, in Übereinstimmung mit der Histopathologie, identifiziert werden. Diese stellt somit eine potentielle Methode zur Detektion und Differenzierung molekularer Gewebeveränderungen dar. Vor allem die Raman-Spektroskopie in Kombination mit katheterbasierten visuellen Techniken könnte die in-vivo Diagnostik vulnerabler Plaques weitreichend verbessern

Image segmentation by graph partitioning

In this paper we propose an hybrid method for the image segmentation which combines the edge-based, region-based and the morphological techniques in conjunction through the spectral based clustering approach. An initial partitioning of the image into atomic regions is set by applying a watershed method to the image gradient magnitude. This initial partition is the input to a computationally efficient region segmentation process which produces the final segmentation. We have applied our approach on several images of the Berkeley Segmentation Dataset. The results reveal the accuracy of the propose method