215 research outputs found
Sex differences in clinical outcomes following surgical treatment of femoroacetabular impingement
BACKGROUND: Sex-based differences in clinical outcomes following surgical treatment of femoroacetabular impingement remain largely uncharacterized; this prospective, multicenter study evaluated these differences both directly and adjusted for covariates.
METHODS: Hips undergoing surgical treatment of symptomatic femoroacetabular impingement were prospectively enrolled in a multicenter cohort. Patient demographics, radiographic parameters, intraoperatively assessed disease severity, and history of surgical procedures, as well as patient-reported outcome measures, were collected preoperatively and at a mean follow-up of 4.3 years. A total of 621 (81.6%) of 761 enrolled hips met the minimum 1 year of follow-up and were included in the analysis; 56.7% of analyzed hips were female. Univariate and multivariable statistics were utilized to assess the direct and adjusted differences in outcomes, respectively.
RESULTS: Male hips had greater body mass index and larger α angles. Female hips had significantly lower preoperative and postoperative scores across most patient-reported outcome measures, but also had greater improvement from preoperatively to postoperatively. The preoperative differences between sexes exceeded the threshold for the minimal clinically important difference of the modified Harris hip score (mHHS) and all Hip disability and Osteoarthritis Outcome Score (HOOS) domains except quality of life. Preoperative sex differences in mHHS, all HOOS domains, and Short Form-12 Health Survey physical function component score were greater than the postoperative differences. A greater proportion of female hips achieved the minimal clinically important difference for the mHHS, but male hips were more likely to meet the patient acceptable symptom state for this outcome. After adjusting for relevant covariates with use of multiple regression analysis, sex was not identified as an independent predictor of any outcome. Preoperative patient-reported outcome scores were a strong and highly significant predictor of all outcomes.
CONCLUSIONS: Significant differences in clinical outcomes were observed between sexes in a large cohort of hips undergoing surgical treatment of femoroacetabular impingement. Despite female hips exhibiting lower baseline scores, sex was not an independent predictor of outcome or reoperation.
LEVEL OF EVIDENCE: Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence
Periacetabular osteotomy with or without arthroscopic management in patients with hip dysplasia: Study protocol for a multicenter randomized controlled trial
BACKGROUND: Hip dysplasia is one of the most common causes of hip arthritis. Its incidence is estimated to be between 3.6 and 12.8% (Canadian Institute for Health Information, Hip and knee replacements in Canada, 2017-2018: Canadian joint replacement registry annual report, 2019; Jacobsen and Sonne-Holm, Rheumatology 44:211-8, 2004). The Periacetabular Osteotomy (PAO) has been used successfully for over 30 years (Gosvig et al., J Bone Joint Surg Am 92:1162-9, 2010), but some patients continue to exhibit symptoms post-surgery (Wyles et al., Clin Orthop Relat Res 475:336-50, 2017). A hip arthroscopy, performed using a small camera, allows surgeons to address torn cartilage inside the hip joint. Although both procedures are considered standard of care treatment options, it is unknown whether the addition of hip arthroscopy improves patient outcomes compared to a PAO alone. To delay or prevent future joint replacement surgeries, joint preservation surgery is recommended for eligible patients. While previous studies found an added cost to perform hip arthroscopies, the cost-effectiveness to Canadian Health care system is not known.
METHODS: Patients randomized to the experimental group will undergo central compartment hip arthroscopy prior to completion of the PAO. Patients randomized to the control group will undergo isolated PAO. Patient-reported quality of life will be the primary outcome used for comparison between the two treatment groups as measured by The International Hip Outcome Tool (iHOT-33) (Saberi Hosnijeh et al., Arthritis Rheum 69:86-93, 2017). Secondary outcomes will include the four-square step test and sit-to-stand (validated in patients with pre-arthritic hip pain) and hip-specific symptoms and impairment using the HOOS; global health assessment will be compared using the PROMIS Global 10 Score; health status will be assessed using the EQ-5D-5L and EQ VAS questionnaires (Ganz et al., Clin Orthop Relat Res 466:264-72, 2008) pre- and post-operatively. In addition, operative time, hospital length of stay, adverse events, and health services utilization will be collected. A sub-group of patients (26 in each group) will receive a T1rho MRI before and after surgery to study changes in cartilage quality over time. A cost-utility analysis will be performed to compare costs and quality-adjusted life years (QALYs) associated with the intervention.
DISCUSSION: We hypothesize that (1) concomitant hip arthroscopy at the time of PAO to address central compartment pathology will result in clinically important improvements in patient-reported outcome measures (PROMs) versus PAO alone, that (2) additional costs associated with hip arthroscopy will be offset by greater clinical improvements in this group, and that (3) combined hip arthroscopy and PAO will prove to be a cost-effective procedure.
TRIAL REGISTRATION: ClinicalTrials.gov NCT03481010 . Registered on 6 March 2020. Protocol version: version 3
Formation of Mobile Chromatin-Associated Nuclear Foci Containing HIV-1 Vpr and VPRBP Is Critical for the Induction of G2 Cell Cycle Arrest
HIV-1 Viral protein R (Vpr) induces a cell cycle arrest at the G2/M phase by activating the ATR DNA damage/stress checkpoint. Recently, we and several other groups showed that Vpr performs this activity by recruiting the DDB1-CUL4A (VPRBP) E3 ubiquitin ligase. While recruitment of this E3 ubiquitin ligase complex has been shown to be required for G2 arrest, the subcellular compartment where this complex forms and functionally acts is unknown. Herein, using immunofluorescence and confocal microscopy, we show that Vpr forms nuclear foci in several cell types including HeLa cells and primary CD4+ T-lymphocytes. These nuclear foci contain VPRBP and partially overlap with DNA repair foci components such as γ-H2AX, 53BP1 and RPA32. While treatment with the non-specific ATR inhibitor caffeine or depletion of VPRBP by siRNA did not inhibit formation of Vpr nuclear foci, mutations in the C-terminal domain of Vpr and cytoplasmic sequestration of Vpr by overexpression of Gag-Pol resulted in impaired formation of these nuclear structures and defective G2 arrest. Consistently, we observed that G2 arrest-competent sooty mangabey Vpr could form these foci but not its G2 arrest-defective paralog Vpx, suggesting that formation of Vpr nuclear foci represents a critical early event in the induction of G2 arrest. Indeed, we found that Vpr could associate to chromatin via its C-terminal domain and that it could form a complex with VPRBP on chromatin. Finally, analysis of Vpr nuclear foci by time-lapse microscopy showed that they were highly mobile and stable structures. Overall, our results suggest that Vpr recruits the DDB1-CUL4A (VPRBP) E3 ligase to these nuclear foci and uses these mobile structures to target a chromatin-bound cellular substrate for ubiquitination in order to induce DNA damage/replication stress, ultimately leading to ATR activation and G2 cell cycle arrest
Colorectal cancer prevention by non-steroidal anti-inflammatory drugs: effects of dosage and timing
Epidemiological studies show that non-steroidal anti-inflammatory drugs (NSAIDs) reduce colorectal cancer incidence. We measured the rate ratio for colorectal adenocarcinoma according to dosage and the timing of exposure by means of a case–control study, nested in a non-concurrent cohort linkage study, using the population of beneficiaries of the Saskatchewan Prescription Drug Plan from 1981 to 1995 with no history of cancer since 1970 as the source population. Four controls per case, matched on age and gender and alive when the case was diagnosed, were randomly selected. Dispensing rates, calculated over successive time periods, characterized NSAID exposure. We accrued 3844 cases of colon cancer and 1971 cases of rectal cancer. For colon cancer a significant trend towards a decreasing rate ratio was associated with increasing exposure during the 6 months preceding diagnosis (P-trend = 0.002). For both cancers, significant trends were associated with exposure 11–15 years before diagnosis (colon: P-trend = 0.01; rectum: P-trend = 0.0001). At the highest exposure levels the rate ratio for colon cancer was 0.57 (95% confidence interval (CI) 0.36–0.89); for rectal cancer it was 0.26 (95% CI 0.11–0.61). No protection was associated with exposure during other periods. The timing of NSAID use must be considered in planning intervention trials to prevent colorectal cancer. There may be a 10-year delay before any preventive effect will appear. © 1999 Cancer Research Campaig
Involvement of Lgl and Mahjong/VprBP in Cell Competition
Mahjong is a novel Lethal giant larvae-binding protein that plays a vital role in cell competition in both flies and mammals
γ-Glutamylcysteine detoxifies reactive oxygen species by acting as glutathione peroxidase-1 cofactor
Reactive oxygen species regulate redox-signaling processes, but in excess they can cause cell damage, hence underlying the aetiology of several neurological diseases. Through its ability to down modulate reactive oxygen species, glutathione is considered an essential thiol-antioxidant derivative, yet under certain circumstances it is dispensable for cell growth and redox control. Here we show, by directing the biosynthesis of γ-glutamylcysteine—the immediate glutathione precursor—to mitochondria, that it efficiently detoxifies hydrogen peroxide and superoxide anion, regardless of cellular glutathione concentrations. Knocking down glutathione peroxidase-1 drastically increases superoxide anion in cells synthesizing mitochondrial γ-glutamylcysteine. In vitro, γ-glutamylcysteine is as efficient as glutathione in disposing of hydrogen peroxide by glutathione peroxidase-1. In primary neurons, endogenously synthesized γ-glutamylcysteine fully prevents apoptotic death in several neurotoxic paradigms and, in an in vivo mouse model of neurodegeneration, γ-glutamylcysteine protects against neuronal loss and motor impairment. Thus, γ-glutamylcysteine takes over the antioxidant and neuroprotective functions of glutathione by acting as glutathione peroxidase-1 cofactor
Genome-wide association study for resistance to the Meloidogyne javanica causing root-knot nematode in soybean.
Key message A locus on chromosome 13, containing multiple TIR-NB-LRR genes and SNPs associated with M. javanica resistance, was identified using a combination of GWAS, resequencing, genetic mapping and expression profiling. Abstract Meloidogyne javanica, a root-knot nematode, is an important problem in soybean-growing areas, leading to severe yield losses. Some accessions have been identified carrying resistance loci to this nematode. In this study, a set of 317 soybean accessions was characterized for resistance to M. javanica. A genome-wide association study was performed using SNPs from genotyping-by-sequencing, and a region of 29.2 kb on chromosome 13 was identified. An analysis of haplotypes showed that SNPs were able to discriminate between susceptible and resistant accessions, with 25 accessions sharing the haplotype associated with resistance. Furthermore, five accessions that exhibited resistance without carrying this haplotype may carry different loci conferring resistance to M. javanica. We also conducted the screening of the SNPs in the USDA soybean germplasm, revealing that several soybean accessions previously reported as resistant to other nematodes also shared the resistance haplotype on chromosome 13. Two SNP-based TaqMan® assays were developed and validated in two panels of soybean cultivars and in biparental populations. In silico analysis of the region associated with resistance identified the occurrence of genes with structural similarity with classical major resistance genes (NBS-LRR genes). Specifically, several nonsynonymous SNPs were observed in Glyma.13g194800 and Glyma.13g194900. The expression profile of these candidate genes demonstrated that the two gene models were up-regulated in the resistance source PI 505,099 after nematode infection. Overall, the SNPs associated with resistance and the genes identified constitute an important tool for introgression of resistance to the root-knot nematode by marker-assisted selection in soybean breeding programs.Artigo de acesso aberto
Characterization of the Molecular Determinants of Primary HIV-1 Vpr Proteins: Impact of the Q65R and R77Q Substitutions on Vpr Functions
Although HIV-1 Vpr displays several functions in vitro, limited information exists concerning their relevance during infection. Here, we characterized Vpr variants isolated from a rapid and a long-term non-progressor (LTNP). Interestingly, vpr alleles isolated from longitudinal samples of the LTNP revealed a dominant sequence that subsequently led to diversity similar to that observed in the progressor patient. Most of primary Vpr proteins accumulated at the nuclear envelope and interacted with host-cell partners of Vpr. They displayed cytostatic and proapoptotic activities, although a LTNP allele, harboring the Q65R substitution, failed to bind the DCAF1 subunit of the Cul4a/DDB1 E3 ligase and was inactive. This Q65R substitution correlated with impairment of Vpr docking at the nuclear envelope, raising the possibility of a functional link between this property and the Vpr cytostatic activity. In contradiction with published results, the R77Q substitution, found in LTNP alleles, did not influence Vpr proapoptotic activity
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