Lactoyl leucine and isoleucine are bioavailable alternatives for canonical amino acids in cell culture media.

Increasing demands for protein-based therapeutics such as monoclonal antibodies, fusion proteins, bispecific molecules, and antibody fragments require researchers to constantly find innovative solutions. To increase yields and decrease costs of next generation bioprocesses, highly concentrated cell culture media formulations are developed but often limited by the low solubility of amino acids such as tyrosine, cystine, leucine, and isoleucine, in particular at physiological pH. This study sought to investigate highly soluble and bioavailable derivatives of leucine and isoleucine that are applicable for fed-batch processes. N-lactoyl-leucine and N-lactoyl-isoleucine sodium salts were tested in cell culture media and proved to be beneficial to increase the overall solubility of cell culture media formulations. These modified amino acids proved to be bioavailable for various Chinese hamster ovary (CHO) cells and were suitable for replacement of canonical amino acids in cell culture feeds. The quality of the final recombinant protein was studied in bioprocesses using the derivatives, and the mechanism of cleavage was investigated in CHO cells. Altogether, both N-lactoyl amino acids represent an advantageous alternative to canonical amino acids to develop highly concentrated cell culture media formulations to support next generation bioprocesses.

Risk Factors for Revision Surgery Following Radial Head Arthroplasty without Cement for Unreconstructible Radial Head Fractures: Minimum 3-Year Follow-up.

BACKGROUND: Revision rates following radial head arthroplasty (RHA) for unreconstructible radial head fractures (RHFs) differ vastly in the literature, and little is known about the risk factors that are associated with revision surgery. The purposes of this study were to assess the revision rate following RHA and to determine the associated risk factors. METHODS: A total of 122 patients (mean age, 50.7 years; range, 18 to 79 years) with 123 RHAs who underwent RHA for unreconstructible RHFs between 1994 and 2014 and were ≥3 years out from surgery were included. Demographic variables, injury and procedure-related characteristics, radiographic findings, complications, and revision procedures were assessed. Cox regression analysis was performed to identify the risk factors that were associated with revision surgery following RHA. RESULTS: The median follow-up for the study cohort was 7.3 years (interquartile range [IQR], 5.1 to 10.1 years). All of the patients had unreconstructible RHFs: Mason-Johnston type-IV injuries were the most prevalent (80 [65%]). One or more associated osseous or ligamentous injuries were seen in 89 elbows (72.4%). The median time to surgery was 7 days (IQR, 3 to 11 days). Implanted prostheses were categorized as rigidly fixed (65 [52.8%]) or loosely fixed (58 [47.2%]). A total of 28 elbows (22.8%) underwent revision surgery at a median of 1.1 years (IQR, 0.3 to 3.8 years), with the majority of elbows (17 [60.7%]) undergoing revision surgery within the first 2 years. The most common reason for revision surgery was painful implant loosening (14 [29.2% of 48 complications]). Univariate Cox regression suggested that Workers' Compensation claims (hazard ratio [HR], 5.48; p < 0.001) and the use of an external fixator (HR, 4.67; p = 0.007) were significantly associated with revision surgery. CONCLUSIONS: Revision rates following RHA for unreconstructible RHFs are high; the most common cause for revision surgery is painful implant loosening. Revision surgeries are predominantly performed within the first 2 years after implantation, and surgeons should be aware that Workers' Compensation claims and the use of an external fixator in management of the elbow injury are associated with revision surgery. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Long-term outcome and survival rate of monopolar radial head replacement.

BACKGROUND: The purposes of this study were (1) to report functional outcomes; (2) to assess complications, revisions, and survival rate; and (3) to assess differences in functional outcomes between removed and retained radial head arthroplasties (RHAs), early and delayed treatment, and type of RHA used at long-term follow-up after monopolar RHA for unreconstructible radial head fractures or their sequelae. METHODS: Seventy-eight patients (mean age, 59.2 years) who were at least 6 years postoperatively after monopolar RHA for unreconstructible RHFs or their sequelae were included. The Mayo Elbow Performance Score (MEPS); Quick Disability of the Arm, Shoulder, and Hand (QuickDASH) score; visual analog scale; postoperative satisfaction (1-6, 6 = highly unsatisfied); range of motion; complications; and revisions were assessed. Radiographic findings were reported. Kaplan-Meier survival analysis was performed. Subgroups (RHA type, early vs. delayed surgery, RHA removed vs. retained) were compared. RESULTS: At a median clinical follow-up of 9.5 years (range: 6.0-28.4 years), median MEPS was 80.0 (interquartile range [IQR]: 60.0-97.5), median QuickDASH was 22.0 (IQR: 4.6-42.6), median visual analog scale was 1 (IQR: 0-4), median postoperative satisfaction was 2 (IQR: 1-3), and median arc of extension/flexion was 110° (IQR: 80°-130°). Radiographic follow-up was available for 48 patients at a median of 7.0 years (range: 2.0-15.0 years). Heterotopic ossifications were seen in 14 (29.2%), moderate-to-severe capitellar osteopenia/abrasion in 3 (6.1%), moderate-to-severe ulnohumeral degeneration in 3 (6.1%), and periprosthetic radiolucencies in 17 (35.4%) patients. Twenty-nine patients (37.2%) had complications and 20 patients (25.6%) underwent RHA exchange or removal. Kaplan-Meier analysis with failure defined as RHA exchange or removal demonstrated survival of 75.1% (95% confidence interval: 63.7-83.3) at 18 years. The highest annual failure rate was observed in the first year in which the RHAs of 7 patients (9%) were exchanged or removed. No significant differences were detected between type of RHA in MEPS (Mathys: 82.5 [75.0-100] vs. Evolve: 80.0 [60.0-95.0]; P = .341) and QuickDASH (Mathys: 12.5 [0-34.4] vs. Evolve: 26.7 [6.9-46.2]; P = .112). Early surgery (≤3 weeks) yielded significantly superior MEPS (80.0 [70.0-100.0] vs. 52.5 [30.0-83.8]; P = .014) and QuickDASH (18.6 [1.5-32.6] vs. 46.2 [31.5-75.6]; P = .002) compared with delayed surgery (>3 weeks). Patients with retained RHAs had significantly better MEPS (80.0 [67.5-100] vs. 70.0 [32.5-82.5]; P = .016) and QuickDASH (18.1 [1.7-31.9] vs. 49.1 [22.1-73.8]; P = .007) compared with patients with removed RHAs. CONCLUSIONS: Long-term outcomes for RHA are satisfactory; however, there is a high complication and revision rate, resulting in implant survival of 75.1% at 18 years with the highest annual failure rate observed in the first postoperative year.

Keto leucine and keto isoleucine are bioavailable precursors of their respective amino acids in cell culture media.

Highly concentrated cell culture media formulations are essential to develop next generation bioprocesses used to produce therapeutic monoclonal antibodies, fusion proteins, bispecific molecules and mAb fragments. Although cysteine/cystine and tyrosine are the first components preventing the development of highly concentrated complex cell culture media, leucine and isoleucine were identified as the next critical amino acids due to their limited solubility. This work sought to investigate highly soluble and readily bioavailable derivatives of both amino acids that may be used in batch, fed-batch or perfusion processes. The α-keto acids of Leu and Ile, keto leucine and keto isoleucine sodium salts, were tested in cell culture media and proved to be beneficial to increase the overall solubility of cell culture media formulations. These keto acids were readily bioavailable for various CHO cells and can be used in both media and feeds. The quality of the final recombinant protein was studied in processes using the precursors and the mechanism of amination was investigated in CHO cells. Altogether, both keto acids represent an alternative to their respective amino acids to develop highly concentrated cell culture media formulations to support next generation bioprocesses.

Monteggia-like lesions in adults treated with radial head arthroplasty-mid-term follow-up of 27 cases.

BACKGROUND: The aim of the study was to analyze the functional and radiological outcome of Monteggia-like lesions in adults with unreconstructible fracture of the radial head and treatment with radial head arthroplasty. METHODS: Twenty-seven patients (mean age 56 years; range 36 to 79 years) with a Monteggia-like lesion and treatment with radial head replacement were included in this retrospective study. Minimum follow-up was 2 years. Clinical assessment included the pain level with the visual analog scale in rest (VASR) and under pressure (VASP), range of motion, Mayo Elbow Performance Score (MEPS), and Disability of the Arm, Shoulder, and Hand score (DASH). A detailed radiological evaluation was performed. Complications and revisions were also analyzed. RESULTS: After a mean follow-up period of 69 months (range, 24 to 170) the mean DASH score was 30 ± 24, the MEPS averaged 77 ± 20 points, the mean VASR was 2.1 ± 2.4, and VASP was 4.5 ± 3.5. Mean loss of extension was 24° ± 18 and flexion was 124° ± 20. Heterotopic ossifications were noted in 12 patients (44%). A total of 17 complications were noted in 11 patients (41%), leading to 15 revision surgeries in 9 patients (33%). Patients with a complicated postoperative course showed a worse clinical outcome compared with patients without complications measured by MEPS (68 ± 22 vs. 84 ± 16), DASH (49 ± 16 vs. 20 ± 22) and ulnohumeral motion (77° ± 31 vs. 117° ± 23). CONCLUSIONS: Monteggia-like lesions with unreconstructible radial head fracture and treatment with radial head replacement are prone to complications and revisions.

Low return-to-sports rate after elbow injury and treatment with radial head arthroplasty.

BACKGROUND: The aim of this study was to analyze sports participation after radial head arthroplasty among recreational athletes. METHODS: A total of 57 recreational athletes (mean age, 49 years; age range, 18-79 years) treated with radial head arthroplasty for non-reconstructible radial head fractures were included in this retrospective study. The return-to-sports rate and the time to return to sports were analyzed. The clinical and radiologic outcomes were compared between patients who returned to sports (group 1) and those who did not (group 2). RESULTS: After a mean follow-up period of 8.4 years (range, 2.5-16.4 years), 30 of 57 patients (53%) had returned to sports. The mean sports frequency significantly decreased from 5.2 ± 5.0 h/week to 2.2 ± 2.9 h/week after surgery (P < .001). In group 1, 83% of patients returned to the same sports activity whereas 17% changed to a less demanding sports activity. The mean time to return to sports was 158 days (range, 21-588 days). Patients who returned to sports had a significantly better Mayo Elbow Performance Score (MEPS) (84 ± 19 points vs. 63 ± 20 points, P < .001); Disabilities of the Arm, Shoulder and Hand score (16 ± 17 vs. 46 ± 22, P < .001); and arc of flexion (114° ± 32° vs. 89° ± 36°, P = .007). A secondary radial head prosthesis (P = .046) and MEPS lower than 85 points (P = .001) were associated with a significantly lower return-to-sports rate. No differences regarding radiographic changes were found between the 2 groups (P ≥ .256). CONCLUSION: The return-to-sports rate after radial head replacement is low. A secondary radial head prosthesis and a worse clinical outcome (MEPS < 85 points) significantly increase the risk of not returning to sports after radial head arthroplasty.

Effect of surgical decompression of spinal metastases in acute treatment - Predictors of neurological outcome.

OBJECTIVE: Space-occupying spinal metastases (SM), commonly diagnosed because of acute neurological deterioration, consequently lead to immediate decompression with tumor removal or debulking. In this study, we analyzed a series of patients with surgically treated spinal metastases and explicitly sought to determine individual predictors of functional outcome. PATIENTS AND METHODS: 94 patients (26 women, 68 men; mean age 64.0 years) with spinal metastases, who had been surgically treated at our department, were included retrospectively. We reviewed the pre- and postoperative charts, surgical reports, radiographic data for demographics, duration of symptoms, histopathology, stage of systemic disease, co-morbidities, radiographic extension, surgical strategy, neurological performance (Frankel Grade Classification), and the Karnofsky Performance Index (KPI). RESULTS: Emergency surgery within <24 h after discharge had been conducted in 33% of patients. Prostate carcinoma (29.5%) and breast carcinoma (11.6%) were the most common histopathologies. Median KPI was 60% at admission that had significantly improved at discharge (KPI 70%; p = 0.01). The rate of complications without revision was 4.3%, the revision rate 4.2%. From admission to discharge, pain had been significantly reduced (p = 0.019) and motor deficits significantly improved (p = 0.003). KPI had been significantly improved during in-hospital treatment (median 60 vs 70, p = 0.010). In the multivariable analysis, predictors of poor outcome (KPI < 70) were male sex, multiple metastases, and pre-existing bowel and bladder dysfunction. Median follow up was 2 months. DISCUSSION: In our series, surgery for spinal metastases (laminectomy, tumor removal, and mass reduction) significantly reduced pain as well as sensory and motor deficits. We identified male sex, multiple metastases, and pre-existing bowel and bladder dysfunction as predictors of negative outcome.

Systematic investigation of zinc aminoalkylphosphonates: influence of the alkyl chain lengths on the structure formation.

With the high-throughput (HT) methodology, the bifunctional aminoalkylphosphonic acids (AAPA) linker molecules 2-aminoethyl- (AEPA), 3-aminopropyl- (APPA), and 4-aminobutylphosphonic acid (ABPA) [HO(3)P-C(n)H(2n)-NH(2) (n = 2-4)] and zinc nitrate were used to synthesize new metal phosphonates in order to investigate the influence of the alkyl chain length on the structure formation. The systematic investigations led to one known (ZnO(3)PC(2)H(4)NH(2)) and six new compounds: one using AEPA, three using APPA, and two using ABPA. The crystal structures of five compounds were determined by single crystal X-ray diffraction, using X-ray powder diffraction (XRPD) data as well as structure modeling employing force field methods. For compound 1, Zn(O(3)P-C(2)H(4)-NH(3))(NO(3))(H(2)O) (monoclinic, Cc, a = 4.799(1) Å, b = 29.342(6) Å, c = 5.631(1) Å, ß = 91.59(3)°, V = 792.7(3) Å(3), Z = 4), and compound 2, Zn(2)(OH)(O(3)P-C(3)H(6)-NH(3))(NO(3)) (monoclinic, P2/c, a = 12.158(2) Å, b = 5.0315(10) Å, c = 13.952(3) Å, ß = 113.23(3)°, V = 784.3(3) Å(3), Z = 2), the structures were determined using single crystal X-ray diffraction data. The crystal structures of [Zn(O(3)P-C(3)H(6)-NH(2))]·H(2)O (3) (monoclinic, P2(1)/c, a = 9.094(2) Å, b = 5.0118(7) Å, c = 16.067(4) Å, ß = 90.38(2)°, V = 732.3(2) Å(3), Z = 4) and Zn(O(3)P-C(4)H(8)-NH(2)) (5) (monoclinic, P2(1)/c, a = 8.570(7) Å, b = 8.378(4) Å, c = 9.902(6) Å, ß = 90.94(5)°, V = 710.9(8) Å(3), Z = 4) were determined using XRPD data. The structural model for compound 6, Zn(O(3)P-C(4)H(8)-NH(3))(NO(3))(H(2)O), was established using lattice parameters from XRPD data and following crystal structure modeling employing force field methods. The structures depend strongly on the alkyl chain length n. For n = 2 and 4 isoreticular compounds are observed, while n = 3 leads to new structures. Larger amounts of all compounds were obtained employing scale-up syntheses in a conventional oven as well as in a microwave reactor system. In addition, in situ energy dispersive X-ray diffraction (EDXRD) experiments at 130 °C were performed at beamline F3 at HASYLAB, DESY, Hamburg, to investigate the formation of compounds 2 and 3 as well as the phase transformation of 2 into 3 upon addition of NaOH. All compounds were characterized in detail using X-ray powder diffraction, IR/Raman spectroscopy, and thermogravimetric and elemental analysis.

Solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) -- structural investigations on two different carrier systems.

Two different types of colloidal lipid particles are presented and compared as innovative carrier systems. Size distribution and storage stability of formulations produced by hot high pressure homogenisation in lab and medium scale production were investigated by laser diffractometry (LD) and photon correlation spectroscopy (PCS). Nanoparticles were characterised by their melting and recrystallisation behaviour recorded by differential scanning calorimetry (DSC). Electron microscope investigations were also carried out showing the particulate character of these carriers. Reasons for observed differences in loading capacity are discussed and possibilities for dermal application are described.