Oxidation of phenylalanyl-tRNA synthetase positively regulates translational quality control.

Accurate translation of the genetic code is maintained in part by aminoacyl-tRNA synthetases (aaRS) proofreading mechanisms that ensure correct attachment of a cognate amino acid to a transfer RNA (tRNA). During environmental stress, such as oxidative stress, demands on aaRS proofreading are altered by changes in the availability of cytoplasmic amino acids. For example, oxidative stress increases levels of cytotoxic tyrosine isomers, noncognate amino acids normally excluded from translation by the proofreading activity of phenylalanyl-tRNA synthetase (PheRS). Here we show that oxidation of PheRS induces a conformational change, generating a partially unstructured protein. This conformational change does not affect Phe or Tyr activation or the aminoacylation activity of PheRS. However, in vitro and ex vivo analyses reveal that proofreading activity to hydrolyze Tyr-tRNAPhe is increased during oxidative stress, while the cognate Phe-tRNAPhe aminoacylation activity is unchanged. In HPX-, Escherichia coli that lack reactive oxygen-scavenging enzymes and accumulate intracellular H2O2, we found that PheRS proofreading is increased by 11%, thereby providing potential protection against hazardous cytoplasmic m-Tyr accumulation. These findings show that in response to oxidative stress, PheRS proofreading is positively regulated without negative effects on the enzyme's housekeeping activity in translation. Our findings also illustrate that while the loss of quality control and mistranslation may be beneficial under some conditions, increased proofreading provides a mechanism for the cell to appropriately respond to environmental changes during oxidative stress.

Measuring recovery after open lower limb fractures: combined objective functional tests and global perceived recovery outperform narrower metrics and a standard generic patient reported outcome measure.

BACKGROUND: Open lower limb fractures are serious injuries requiring combined ortho-plastic surgery and have significantly worse outcomes than similar closed fractures. There is little objective published data to determine which functional outcome measures best reflect progress or completeness of physical recovery. Our hypothesis was that objective measures combining strength, mobility and balance would better reflect recovery than isolated parameters (e.g. range of motion ROM) and would compare well to patients' perceived recovery. METHODS: Adult open lower limb fracture patients were reviewed 6 and 12 weeks, 6, 9 and 12 months post-injury. The mechanism, injury pattern, age, gender and treatment were recorded. Isolated parameter objective functional outcome measures (OFOMs) (ROM and MRC strength grade) were compared to combined OFOMs (timed up and go, comfortable gait speed and fast gait speed, Edgren Side Step Test (TUAG, CGS, FGS, ESST) and Single Leg balance. Patient reported outcomes were recorded (Global Perceived Effect (GPE) score and Disability Rating Index (DRI)). Statistical analysis used non-parametric tests (e.g. Spearman correlation) compared each with time since injury. RESULTS: Sixty-eight patients (54 male) with a median age of 45(20-75) years. Of the 19 isolated OFOMs, only knee flexion and ankle plantar flexion ROM and strength improved with time (Spearman correlation p = 0.042, 0.008, 0.032, 0.036 respectively). TUAG, ESST, CGS, FGS and GPE scores showed significant improvement (Spearman correlation p < 0.001). Patients' estimation of recovery paralleled these measures (Spearman correlation p < 0.001) with all but 2 patients achieving the minimum clinical important difference in DRI by 12 months compared to baseline. However, the GPE score had a higher proportion of improving responses than DRI at each time-point. DISCUSSION: Functional recovery is a key determinant in patients returning to work, providing for themselves and their family or resuming independent living for older patients. This study has demonstrated time-related improvements in combined OFOMs measuring mobility, strength, agility and balance paralleling patients' perception of recovery in the 12 months after open lower limb fractures. Over the same time-frame, the simple GPE score compared favourably with the DRI. Such parameters could become part of a defined core outcomes set. Focussing rehabilitation towards these combined OFOMs may help hasten recovery. TRIAL REGISTRATION: South West Wales REC 06/WMW02/10).

Aminoacyl-tRNA quality control is required for efficient activation of the TOR pathway regulator Gln3p.

The aminoacylation status of the cellular tRNA pool regulates both general amino acid control (GAAC) and target of rapamycin (TOR) stress response pathways in yeast. Consequently, fidelity of translation at the level of aminoacyl-tRNA synthesis plays a central role in determining accuracy and sensitivity of stress responses. To investigate effects of translational quality control (QC) on cell physiology under stress conditions, phenotypic microarray analyses were used to identify changes in QC deficient cells. Nitrogen source growth assays showed QC deficient yeast grew differently compared to WT. The QC deficient strain was more tolerant to caffeine treatment than wild type through altered interactions with the TOR and GAAC pathways. Increased caffeine tolerance of the QC deficient strain was consistent with the observation that the activity of Gln3p, a transcription factor controlled by the TOR pathway, is decreased in the QC deficient strain compared to WT. GCN4 translation, which is typically repressed in the absence of nutritional stress, was enhanced in the QC deficient strain through TOR inhibition. QC did not impact cell cycle regulation; however, the chronological lifespan of QC deficient yeast strains decreased compared to wild type, likely due to translational errors and alteration of the TOR-associated regulon. These findings support the idea that changes in translational fidelity provide a mechanism of cellular adaptation by modulating TOR activity. This, in turn, supports a central role for aminoacyl-tRNA synthesis QC in the integrated stress response by maintaining the proper aa-tRNA pools necessary to coordinate the GAAC and TOR.

Neonatal ear splinting for congenital ear deformities✰.

Splinting of ears in neonates to correct the congenital auricular deformities has been well described. Despite being a non-invasive technique and having a potential to prevent need for correctional surgery, it's up-take across the UK has been poor. This study evaluates the outcomes of neonatal ear splinting for congenital ear deformities from a regional ear splinting service. The retrospective study of patients undergoing neonatal ear splinting from 2009- 2015 was conducted at the Welsh Centre for Burns and Plastic Surgery. A total of 82 (n = 123 ears) neonates were treated. At the cessation of treatment 93% were reported as improved/excellent by a clinician. Longer-term parent evaluation showed improved/excellent result in 78.89%. Neonatal ear splinting is relatively inexpensive and has a high rate of success for a variety of neonatal ear deformities. Promoting awareness, identifying patients early and commencing treatment may reduce surgical correction of auricular deformities.

Objective and Patient-reported Assessments of Skin Grafts and Keystone Flaps-A Pilot Retrospective Cohort Study.

BACKGROUND: The keystone perforator island flap provides a versatile form of reconstruction. Perceived benefits include better donor-recipient color match, less contour defect, and fewer complications. To date, there has been no high-quality evidence comparing keystone flaps to split-thickness skin grafts (SSG) from both a qualitative and quantitative point of view. METHODS: The Objective and Patient Reported Assessments of Skin grafts versus Keystone flap cohort study compares keystone flaps with SSGs for the reconstruction of skin cancer defects. Patient-reported outcome measures were collected using the EuroQol 5 dimension scale and Patient and Observer Scar Assessment Scale (POSAS) questionnaires. Objective assessments of skin quality were assessed with the Courage and Khazaka system. Cost analysis was also performed. RESULTS: Thirty-eight patients were studied: 20 keystone flaps and 18 SSGs. The keystone group had higher EuroQol 5 dimension scale scores (keystone median = 1.0; SSG median = 0.832; P = 0.641) indicating better general quality of life and lower POSAS scores indicating better disease/condition specific quality of life (keystone mean = 27.7; SSG mean = 35.7; P = 0.323). Observer POSAS scores were significantly lower in the keystone group compared with the SSG group (keystone mean = 10.889; SSG mean = 17.313; P < 0.001). Preservation of sensation was significantly better in keystone flaps (P = 0.006). There was an average £158/$207 (15%) saving when performing a keystone flap. CONCLUSION: This pilot study demonstrates a number of possible benefits of keystone flaps over SSGs. The results demonstrate the need for further research comparing these reconstructive options. We propose a prospective, controlled study using the methods developed in this pilot study.

Long-term outcomes of microsurgical nasal replantation: review of the literature and illustrated 10-year follow-up of a pediatric case with full sensory recovery.

We present a case of successful artery only total nose replantation in an 18-month-old child, with 10 years of follow-up and full sensory recovery despite no nerve repair. The common absence of veins for anastomosis does not prevent successful replant, as demonstrated with the use of Hirudo medicinalis use in this unique case. We comprehensively review the literature of this rare and complex injury and advocate microsurgical replantation where possible over other methods of nasal reconstruction.