Effects of 12-Week Resistance Training on Sprint and Jump Performances in Competitive Adolescent Rugby Union Players.

Harries, SK, Lubans, DR, Buxton, A, MacDougall, THJ, and Callister, R. Effects of 12-week resistance training on sprint and jump performances in competitive adolescent rugby union players. J Strength Cond Res 32(10): 2762-2769, 2018-Sprint performance is an important characteristic for success in many sports, including rugby union. Resistance training is used to increase muscular fitness (i.e., strength, endurance, and power) and may also be effective for improving sprint and jump performances. The aims of this study were to examine the effects of resistance training using 2 different periodized programs (linear and daily undulating) on sprint and jump performances and explore relationships between performance measures. Sixteen male (16.9 ± 1.0 years) adolescent rugby union players participated in 12 weeks of resistance training. A further 10 male (15.5 ± 1.0 years) participants were recruited as a control group. Assessments of strength (box squat), 10- and 20-m sprint (electronically timed), and jump height (maximal unloaded (body mass only) and loaded (body mass + 10 kg) countermovement jumps) were conducted before and after 12 weeks training. Large to very large increases in 1 repetition maximum box squat (linear: 33.9%; p < 0.001; effect size (ES) = 1.64; daily undulating: 44.5%; p < 0.001; ES = 2.33) were observed after training. Small decreases were seen in 10-m (linear: -1.6%; p = 0.171; ES = -0.84; daily undulating: -2.5%; p = 0.038; ES = -0.36) and 20-m (linear: -0.5%; p = 0.506; ES = -0.20; daily undulating: -1.7%; p = 0.047; ES = -0.27) sprint times. Small-to-moderate associations between changes in lower-body strength and improvements in 10- and 20-m sprint times were found. Resistance training increases lower-body strength in adolescent rugby union players and increases in lower-body strength may transfer to improved sprinting performance with improvements after daily undulating periodized resistance training slightly superior.

A prospective, proteomics study identified potential biomarkers of encapsulating peritoneal sclerosis in peritoneal effluent.

Encapsulating peritoneal sclerosis (EPS) is a potentially devastating complication of peritoneal dialysis (PD). Diagnosis is often delayed due to the lack of effective and accurate diagnostic tools. We therefore examined peritoneal effluent for potential biomarkers that could predict or confirm the diagnosis of EPS and would be valuable in stratifying at-risk patients and driving appropriate interventions. Using prospectively collected samples from the Global Fluid Study and a cohort of Greek PD patients, we utilized 2D SDSPAGE/ MS and iTRAQ to identify changes in the peritoneal effluent proteome from patients diagnosed with EPS and controls matched for treatment exposure. We employed a combinatorial peptide ligand library to compress the dynamic range of protein concentrations to aid identification of low-abundance proteins. In patients with stable membrane function, fibrinogen γ-chain and heparan sulphate proteoglycan core protein progressively increased over time on PD. In patients who developed EPS, collagen-α1(I), γ-actin and Complement factors B and I were elevated up to five years prior to diagnosis. Orosomucoid-1 and a2-HS-glycoprotein chain-B were elevated about one year before diagnosis, while apolipoprotein A-IV and α1-antitrypsin were decreased compared to controls. Dynamic range compression resulted in an increased number of proteins detected with improved resolution of protein spots, compared to the full fluid proteome. Intelectin-1, dermatopontin, gelsolin, and retinol binding protein-4 were elevated in proteome-mined samples from patients with EPS compared to patients that had just commenced peritoneal dialysis. Thus, prospective analysis of peritoneal effluent uncovered proteins indicative of inflammatory and pro-fibrotic injury worthy of further evaluation as diagnostic/prognostic markers.

The influence of age, sex, and posture on the measurement of atlantodental interval in a normal population.

OBJECTIVE: The atlantodental interval (ADI) is used in assessing atlantoaxial stability. This measurement may potentially be affected by several features encountered during patient examination. This study examined the influence of 3 features: age, sex, and posture, on the measurement of ADI in a normal population. METHODS: The ADI was measured sequentially on 269 lateral cervical radiographs of adults with no demonstrated bony injury. Images were stratified by age and sex with equal representation in each age group. A further 25 asymptomatic adults were assessed for posture using craniovertebral angle measured from digital lateral photographs. The ADI was then measured from a lateral radiograph. The data were examined for correlation between age, craniovertebral angle, and ADI using Spearman rank correlation. The ADI of age groups was compared by Kruskal-Wallis test. The relationship between ADI and sex was examined using Wilcoxon rank sum test. Interaction between age and sex was explored using an interaction term in regression analysis. RESULTS: The ADI decreased with age, median measurements reducing from 2.07 to 0.85 mm across age groups (P < .01). No significant relationship was demonstrated between ADI and sex. No significant interaction was demonstrated between age and sex. Measurements of craniovertebral angle did not correlate with ADI (ρ = 0.03, P = .90). CONCLUSION: The magnitude of ADI decreases with advancing age. Age should be considered a modifying factor when interpreting measurement of ADI, particularly in consideration of potential minor instabilities. Patient sex does not appear to influence ADI, either independently or in interaction with age. Craniocervical posture variation does not influence ADI in an asymptomatic adult population.

Peptide aptamers in label-free protein detection: 2. Chemical optimization and detection of distinct protein isoforms.

The early detection and diagnosis of cancer lies central to successful treatment and improved patient outcome. Current techniques are limited by the nature of the biological receptor and the assays available. This paper reports the use of novel biological probes, peptide aptamers, in detecting cyclin-dependent protein kinases (CDKs) whose activity is important in proliferating and cancerous cells. We describe, specifically, the optimization of an orientated peptide aptamer surface and its utilization in establishing a highly specific, low-nanomolar sensitive, detection protocol for the active form of CDK2. In comparing target binding affinity of two different aptamers (pep6 and pep9), both constructed through the insertion of peptide sequences into the surface of a scaffold protein, one was observed to be consistently more effective. Significantly, the pep9 aptamers were able to detect subtle changes in the conformation of CDK2 associated with activation of its catalytic activity that may be caused by the phosphorylation of a single amino acid (threonine 160). A typical response toward the inactive form of CDK2 was in the range of 0.5-2% of the binding of the active form of CDK2 in the concentration range from 2 to 20 nM. Although antibodies are occasionally able to recognize conformations in their targets, this is the first time that a nonantibody protein probe has been used to detect an active protein isoform. Because peptide aptamers are usually raised against full-length proteins, this raises the possibility that peptide aptamers will be able to extend the repertoire of probes that recognize protein conformations, post-translational modifications (PTMs), or conformations stabilized by PTMs.

An investigation of cervical spinal posture in cervicogenic headache.

BACKGROUND: Cervicogenic headache (CGH) is defined as headache symptoms originating from the cervical spine. Cervical dysfunction from abnormal posture has been proposed to aggravate or cause CGH, but there are conflicting reports as to whether there is an association between posture and CGH. OBJECTIVE: The purpose of this study was to evaluate differences in cervical spinal posture, measured on radiographs, between patients with probable CGH and asymptomatic control participants. DESIGN: A single-blinded comparative measurement design was used. METHODS: Differences in postural variables from radiographs between participants with CGH (n=30) and age- and sex-matched asymptomatic control participants (n=30) were determined using paired t tests or the nonparametric equivalent. Postural variables were general cervical lordosis (GCL, Cobb angle C2-C7), upper cervical lordosis (UCL, sagittal alignment C2 compared with C3-C4), and C2 spinous process horizontal deviation. Logistic regression determined postural variables, increasing the likelihood of CGH. RESULTS: There were no significant differences in posture between the CGH and control groups. The mean GCL was 10.97 degrees (SD=7.50) for the CGH group and 7.17 degrees (SD=5.69) for the control group. The mean UCL was 11.86 degrees (SD=6.46) for the CGH group and 9.44 degrees (SD=4.28) for the control group. The mean C2 spinous process horizontal deviation was 3.00 mm (SD=1.66) for the CGH group and 2.86 mm (SD=2.04) for the control group. However, there was a significant association between greater GCL and an increased likelihood of having CGH (odds ratio=1.08; 95% confidence interval=1.001, 1.191). LIMITATIONS: The findings are limited to an association between GCL and posture, as cause and effect cannot be determined. CONCLUSIONS: The association between greater GCL and increased likelihood of having CGH suggests that GCL might be considered in the treatment of patients with CGH. However, as the data do not support posture as a cause of CGH, it is unknown whether addressing posture would reduce CGH.

Structure-function studies of an engineered scaffold protein derived from stefin A. I: Development of the SQM variant.

Non-antibody scaffold proteins are used for a range of applications, especially the assessment of protein-protein interactions within human cells. The search for a versatile, robust and biologically neutral scaffold previously led us to design STM (stefin A triple mutant), a scaffold derived from the intracellular protease inhibitor stefin A. Here, we describe five new STM-based scaffold proteins that contain modifications designed to further improve the versatility of our scaffold. In a step-by-step approach, we introduced restriction sites in the STM open reading frame that generated new peptide insertion sites in loop 1, loop 2 and the N-terminus of the scaffold protein. A second restriction site in 'loop 2' allows substitution of the native loop 2 sequence with alternative oligopeptides. None of the amino acid changes interfered significantly with the folding of the STM variants as assessed by circular dichroism spectroscopy. Of the five scaffold variants tested, one (stefin A quadruple mutant, SQM) was chosen as a versatile, stable scaffold. The insertion of epitope tags at varying positions showed that inserts into loop 1, attempted here for the first time, were generally well tolerated. However, N-terminal insertions of epitope tags in SQM had a detrimental effect on protein expression.

Proteomic analysis of IgE-mediated secretion by LAD2 mast cells.

The LAD2 cell line is a relatively recent addition to the range of mast cell analogues and is of particular importance as it is the only human analogue which can be stimulated to degranulate in an IgE-dependent manner. Mast cells are tissue-based effector cells which have historically been shown to play an important role in the adaptive immune response, though there is now gathering evidence of their significance as a component of the innate immune system. These functions can be attributed to the ability of mast cells to regulate secretion of a wide variety of potent biologically active mediators through immediate and delayed responses. This well-orchestrated secretory mechanism of the mast cell makes it an ideal model in which to study this event. In this investigation, two-dimensional electrophoresis was employed as part of the proteomic characterization of the LAD2 human mast cell line, focusing in particular on a global analysis of membrane protein relocation after an IgE-mediated stimulatory event. This investigation has identified six membrane-associated protein spots which became phosphorylated upon IgE-mediated activation, 31 protein spots which displayed consistent recruitment to the membrane fraction, and three which were consistently lost from the soluble fraction. The scenario which emerges reveals a series of substantial changes which affect every compartment of the cell, providing evidence for a coordinated response to a secretory stimulus.