The pre-hydrolysis state of p21ras in complex with GTP: new insights into the role of water molecules in the GTP hydrolysis reaction of ras-like proteins

AbstractBackground: In numerous biological events the hydrolysis of guanine triphosphate (GTP) is a trigger to switch from the active to the inactive protein form. In spite of the availability of several high-resolution crystal structures, the details of the mechanism of nucleotide hydrolysis by GTPases are still unclear. This is partly because the structures of the proteins in their active states had to be determined in the presence of non-hydrolyzable GTP analogues (e.g. GppNHp). Knowledge of the structure of the true Michaelis complex might provide additional insights into the intrinsic protein hydrolysis mechanism of GTP and related nucleotides.Results: The structure of the complex formed between p21ras and GTP has been determined by X-ray diffraction at 1.6 Å using a combination of photolysis of an inactive GTP precursor (caged GTP) and rapid freezing (100K). The structure of this complex differs from that of p21ras–GppNHp (determined at 277K) with respect to the degree of order and conformation of the catalytic loop (loop 4 of the switch II region) and the positioning of water molecules around the γ-phosphate group. The changes in the arrangement of water molecules were induced by the cryo-temperature technique.Conclusions: The results shed light on the function of Gln61 in the intrinsic GTP hydrolysis reaction. Furthermore, the possibility of a proton shuffling mechanism between two attacking water molecules and an oxygen of the γ-phosphate group can be proposed for the basal GTPase mechanism, but arguments are presented that render this protonation mechanism unlikely for the GTPase activating protein (GAP)-activated GTPase

Treatment of posttraumatic and focal osteoarthritic cartilage defects of the knee with autologous polymer-based three-dimensional chondrocyte grafts: 2-year clinical results

Autologous chondrocyte implantation (ACI) is an effective clinical procedure for the regeneration of articular cartilage defects. BioSeed®-C is a second-generation ACI tissue engineering cartilage graft that is based on autologous chondrocytes embedded in a three-dimensional bioresorbable two-component gel-polymer scaffold. In the present prospective study, we evaluated the short-term to mid-term efficacy of BioSeed-C for the arthrotomic and arthroscopic treatment of posttraumatic and degenerative cartilage defects in a group of patients suffering from chronic posttraumatic and/or degenerative cartilage lesions of the knee. Clinical outcome was assessed in 40 patients with a 2-year clinical follow-up before implantation and at 3, 6, 12, and 24 months after implantation by using the modified Cincinnati Knee Rating System, the Lysholm score, the Knee injury and Osteoarthritis Outcome Score, and the current health assessment form (SF-36) of the International Knee Documentation Committee, as well as histological analysis of second-look biopsies. Significant improvement (p < 0.05) in the evaluated scores was observed at 1 and/or 2 years after implantation of BioSeed-C, and histological staining of the biopsies showed good integration of the graft and formation of a cartilaginous repair tissue. The Knee injury and Osteoarthritis Outcome Score showed significant improvement in the subclasses pain, other symptoms, and knee-related quality of life 2 years after implantation of BioSeed-C in focal osteoarthritic defects. The results suggest that implanting BioSeed-C is an effective treatment option for the regeneration of posttraumatic and/or osteoarthritic defects of the knee

Termination rates and histological reclassification of active surveillance patients with low- and early intermediate-risk prostate cancer : results of the PREFERE trial

Purpose Active surveillance (AS) strategies for patients with low- and early intermediate-risk prostate cancer are still not consistently defined. Within a controlled randomized trial, active surveillance was compared to other treatment options for patients with prostate cancer. Aim of this analysis was to report on termination rates of patients treated with AS including different grade groups. Methods A randomized trial comparing radical prostatectomy, active surveillance, external beam radiotherapy and brachytherapy was performed from 2013 to 2016 and included 345 patients with low- and early intermediate-risk prostate cancer (ISUP grade groups 1 and 2). The trial was prematurely stopped due to slow accrual. A total of 130 patients were treated with active surveillance. Among them, 42 patients were diagnosed with intermediate-risk PCA. Reference pathology and AS quality control were performed throughout. Results After a median follow-up time of 18.8 months, 73 out of the 130 patients (56%) terminated active surveillance. Of these, 56 (77%) patients were histologically reclassified at the time of rebiopsy, including 35% and 60% of the grade group 1 and 2 patients, respectively. No patients who underwent radical prostatectomy at the time of reclassification had radical prostatectomy specimens ≥ grade group 3. Conclusion In this prospectively analyzed subcohort of patients with AS and conventional staging within a randomized trial, the 2-year histological reclassification rates were higher than those previously reported. Active surveillance may not be based on conventional staging alone, and patients with grade group 2 cancers may be recommended for active surveillance in carefully controlled trials only

Comparative and functional genomics provide insights into the pathogenicity of dermatophytic fungi

ABSTRACT: BACKGROUND: Millions of humans and animals suffer from superficial infections caused by a group of highly specialized filamentous fungi, the dermatophytes, which exclusively infect keratinized host structures. To provide broad insights into the molecular basis of the pathogenicity-associated traits, we report the first genome sequences of two closely phylogenetically related dermatophytes, Arthroderma benhamiae and Trichophyton verrucosum, both of which induce highly inflammatory infections in humans. RESULTS: 97% of the 22.5 megabase genome sequences of A. benhamiae and T. verrucosum are unambiguously alignable and collinear. To unravel dermatophyte-specific virulence-associated traits, we compared sets of potentially pathogenicity-associated proteins, such as secreted proteases and enzymes involved in secondary metabolite production, with those of closely related onygenales (Coccidioides species) and the mould Aspergillus fumigatus. The comparisons revealed expansion of several gene families in dermatophytes and disclosed the peculiarities of the dermatophyte secondary metabolite gene sets. Secretion of proteases and other hydrolytic enzymes by A. benhamiae was proven experimentally by a global secretome analysis during keratin degradation. Molecular insights into the interaction of A. benhamiae with human keratinocytes were obtained for the first time by global transcriptome profiling. Given that A. benhamiae is able to undergo mating, a detailed comparison of the genomes further unraveled the genetic basis of sexual reproduction in this species. CONCLUSIONS: Our results enlighten the genetic basis of fundamental and putatively virulence-related traits of dermatophytes, advancing future research on these medically important pathogens

Safety and clinical outcomes of rituximab therapy in patients with different autoimmune diseases: experience from a national registry (GRAID)

Introduction: Evidence from a number of open-label, uncontrolled studies has suggested that rituximab may benefit patients with autoimmune diseases who are refractory to standard-of-care. The objective of this study was to evaluate the safety and clinical outcomes of rituximab in several standard-of-care-refractory autoimmune diseases (within rheumatology, nephrology, dermatology and neurology) other than rheumatoid arthritis or non-Hodgkin's lymphoma in a real-life clinical setting. Methods: Patients who received rituximab having shown an inadequate response to standard-of-care had their safety and clinical outcomes data retrospectively analysed as part of the German Registry of Autoimmune Diseases. The main outcome measures were safety and clinical response, as judged at the discretion of the investigators. Results: A total of 370 patients (299 patient-years) with various autoimmune diseases (23.0% with systemic lupus erythematosus, 15.7% antineutrophil cytoplasmic antibody-associated granulomatous vasculitides, 15.1% multiple sclerosis and 10.0% pemphigus) from 42 centres received a mean dose of 2,440 mg of rituximab over a median (range) of 194 (180 to 1,407) days. The overall rate of serious infections was 5.3 per 100 patient-years during rituximab therapy. Opportunistic infections were infrequent across the whole study population, and mostly occurred in patients with systemic lupus erythematosus. There were 11 deaths (3.0% of patients) after rituximab treatment (mean 11.6 months after first infusion, range 0.8 to 31.3 months), with most of the deaths caused by infections. Overall (n = 293), 13.3% of patients showed no response, 45.1% showed a partial response and 41.6% showed a complete response. Responses were also reflected by reduced use of glucocorticoids and various immunosuppressives during rituximab therapy and follow-up compared with before rituximab. Rituximab generally had a positive effect on patient well-being (physician's visual analogue scale; mean improvement from baseline of 12.1 mm). Conclusions: Data from this registry indicate that rituximab is a commonly employed, well-tolerated therapy with potential beneficial effects in standard of care-refractory autoimmune diseases, and support the results from other open-label, uncontrolled studies

Clinical outcome after 2 years evaluated by the Modified Cincinnati Knee Rating System

<p><b>Copyright information:</b></p><p>Taken from "Treatment of posttraumatic and focal osteoarthritic cartilage defects of the knee with autologous polymer-based three-dimensional chondrocyte grafts: 2-year clinical results"</p><p>http://arthritis-research.com/content/9/2/R41</p><p>Arthritis Research & Therapy 2007;9(2):R41-R41.</p><p>Published online 23 Apr 2007</p><p>PMCID:PMC1906819.</p><p></p> The score from this system is shown for the entire patient cohort compared with patients with posttraumatic and mild degenerative defects (Jaeger-Wirth score < 3) and patients with osteoarthritic defects (Jaeger-Wirth score = 3). The preoperative and follow-up times are as indicated. Scores are presented as medians; the ends of the boxes define the 25th and 75th centiles, and error bars the 10th and 90th centiles. Where indicated (asterisks), differences were statistically significant (< 0.05) compared with the preoperative situation