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Tim Roberts

Publications and source records attributed to Tim Roberts.

7 recordsLinked to original sources
PubMed2026

The Effectiveness of Passive Half-Time Interventions on Simulated Second-Half Performance in Elite Youth Soccer Players.

The half-time period in soccer provides a potentially important window to implement short-duration interventions aimed at maintaining second-half performance. However, passive rest has been associated with a decline in subsequent physical and technical performance. While re-warm-up strategies are well studied, little is known about the efficacy of technology-based, passive recovery modalities, device-supported interventions that require minimal active movement or physical exertion from the athlete, during half-time intervals. This study examined whether percussive therapy, electrical muscle stimulation, and pneumatic compression can mitigate second-half performance decline in male adolescent soccer players. Forty-three academy-level players (17.5 &#xb1; 0.6 years) completed a simulated soccer protocol including the Loughborough Soccer Pass Test (LSPT), repeated 20-meter sprints, and completed Total Quality of Recovery (TQR) assessments before and after half-time. Participants were randomized into one of four intervention groups during the 15-minute half-time interval: Passive Rest (CON), Percussive Therapy (Theragun Pro; TG), EMS (PowerDot; PD), and Pneumatic Compression (RecoveryAir; COMP). Linear mixed-effects models assessed Time &#xd7; Condition interactions for performance and recovery outcomes. Passive half-time rest led to significant deterioration in technical skill, sprint performance, and perceived recovery (p < .05) for the control group. TG and PD significantly improved technical performance (LSPT scores) compared to the control group (d = 0.65 and 0.72, respectively; p < .01). Furthermore, TG and COMP were effective at maintaining 20-meter sprint times (d = 0.58 and 0.49; p < .01), whereas the control group experienced significant slowing. Perceived recovery (TQR) scores significantly declined in the CON group from First Half to Second Half (16.5 &#xb1; 2.2 to 11.1 &#xb1; 2.3. However, this decline was significantly attenuated in all intervention groups: TG (17.5 &#xb1; 1.9 to 14.2 &#xb1; 1.9), PD (17.3 &#xb1; 1.9 to 15.1 &#xb1; 1.9), and COMP (17.6 &#xb1; 1.9 to 15.9 &#xb1; 2.0). Short-duration passive interventions during half-time can mitigate performance decline in adolescent soccer players. TG and EMS appear most effective for preserving technical skills, while COMP may support perceived recovery. These findings highlight practical strategies for optimizing in-game performance and inform evidence-based half-time protocols.

Humans↗
PubMed2003

Genetic determinants of malignancy in a mouse model for oligodendroglioma.

Oligodendrogliomas of all grades overexpress epidermal growth factor receptor (EGFR), whereas deletion of ink4a/arf is found only in high-grade tumors. We used the S100 beta promoter to generate transgenic mice expressing v-erbB, a transforming allele of EGFR. These mice developed low-grade oligodendroglioma. Transgenic animals heterozygous for ink4a/arf or p53 developed high-grade tumors. Comparative genomic hybridization revealed loss of distal mouse chromosome 4, a region orthologous with human chromosome 1p, which is commonly lost in oligodendroglioma. Our results demonstrate that overexpression of EGFR, an epigenetic observation of uncertain significance in human oligodendroglioma, can initiate oligodendroglioma in the mouse. Furthermore, p53 pathway mutations can mediate the transition from low to high grade. These models hold promise for studying tumor lineage, identifying contributing genetic alterations and evaluating preclinical therapies in this important neoplasm.

Animals↗
PubMed2002

Neuropathology of genetically engineered mice: consensus report and recommendations from an international forum.

The Mouse Models of Cancer Consortium of the NCI sponsored a meeting of neuropathologists and veterinary pathologists in New York City in November of 2000. A rapidly growing number of genetically engineered mice (GEM) predisposed to tumors of the nervous system have led to a concomitant need for neuropathological evaluation and validation of these models. A panel of 13 pathologists reviewed material representing most of the available published and unpublished GEM models of medulloblastoma, primitive neuroectodermal tumor, astrocytoma, oligodendroglioma, mixed glioma, and tumors of the peripheral nerve. The GEM tumors were found to have many similarities and some distinct differences with respect to human disease. After review of the biology and pathology for all models presented, participants were split into groups reflective of clinical expertise in human pathology, tumor biology, neuroimaging, or treatment/intervention. Recommendations were made detailing an extensive and complete neuropathological characterization of animals. Importance was placed on including information on strains, tumor clonality, and examination for genetic mutation or altered gene expression characteristics of the corresponding human malignancy. Specific proposals were made to incorporate GEM models in emerging neuroradiological modalities. Recommendations were also made for preclinical validation of these models in cancer therapeutics, and for incorporation of surrogate markers of tumor burden to facilitate preclinical evaluation of new therapies.

Animals↗
PubMed2002

A head holder for magnetic resonance imaging that allows the stereotaxic alignment of spontaneously occurring intracranial mouse tumors.

The use of stereotaxic neurosurgery in rodent models of human disease requires the alignment of central nervous system (CNS) structures that can be identified and surgically approached with great accuracy. Current technologies make possible development of mouse lines with enhanced predispositions for the development of various diseases including tumors. When such tumors arise in the brain their location is unpredictable. Obtaining a biopsy or stereotaxically delivering local therapy requires that the site of such tumors be known with great precision. We devised a method to correlate images of mouse brain tumors acquired by magnetic resonance imaging (MRI) with stereotaxic coordinates that can be used for obtaining biopsies or administering local therapy. We constructed a head holder containing a pair of tubes filled with a substance that could be imaged by MR and which were separated by varying distances. This allowed the precise localization of the tumor in all three dimensions. The strategy we employed is adaptable to other imaging modalities and to other body sites.

Animals↗
PubMed2002

A comparison of cataract surgery under topical anaesthesia with and without intracameral lignocaine.

PURPOSE: To compare the efficacy of intracameral unpreserved lignocaine with placebo during cataract surgery under topical anaesthesia. METHODS: One hundred and thirty-five consecutive cases undergoing clear corneal phacoemulsification were enrolled in this single surgeon, prospective, double-masked, controlled trial. Patients were randomized into two groups, receiving either intracameral unpreserved lignocaine 1% or placebo (balanced salt solution). Systolic and diastolic blood pressure, pulse rate and peripheral oxygen saturation were recorded preoperatively and during phacoemulsification. The level of intraoperative pain was assessed by a numerical analogue scale ranging between 0 (no pain) and 10 (unbearable pain). Data were compared by Student t-test. RESULTS: Sixty-seven cases received lignocaine (group 1) and 68 received placebo (group 2). Average age was 75 years and 74 years, respectively. Systolic blood pressure, pulse rate, oxygen saturation and pain score showed no statistical difference (P = 0.241, 0.542, 0.712, 0.237, respectively). Diastolic blood pressure showed a weakly significant change (P = 0.023). Patients reported minimal discomfort during surgery in both groups. CONCLUSION: This study found no additional benefit of intracameral unpreserved lignocaine when performing routine clear corneal phacoemulsification under topical anaesthesia.

Aged↗
PubMed2002

Correlation of clinical neuromusculoskeletal and central somatosensory performance: variability in controls and patients with severe and mild focal hand dystonia.

Focal hand dystonia (FHd) is a recalcitrant, disabling movement disorder, characterized by involuntary co-contractions of agonists and antagonists, that can develop in patients who overuse or misuse their hands. The aim of this study was to document clinical neuromusculoskeletal performance and somatosensory responses (magnetoencephalography) in healthy controls and in FHd subjects with mild versus severe hand dystonia. The performance of healthy subjects (n = 17) was significantly better than that of FHd subjects (n =17) on all clinical parameters. Those with mild dystonia (n = 10) demonstrated better musculoskeletal skills, task-specific motor performance, and sensory discrimination, but the performance of sensory and fine motor tasks was slower than that of patients with severe dystonia. In terms of somatosensory evoked field responses (SEFs), FHd subjects demonstrated a significant difference in the location of the hand representation on the x and y axes, lower amplitude of SEFs integrated across latency, and a higher ratio of mean SEF amplitude to latency than the controls. Bilaterally, those with FHd (mild and severe) lacked progressive sequencing of the digits from inferior to superior. On the affected digits, subjects with severe dystonia had a significantly higher ratio of SEF amplitude to latency and a significantly smaller mean volume of the cortical hand representation than those with mild dystonia. Severity of dystonia positively correlated with the ratio of SEF mean amplitude to latency (0.9029 affected, 0.8477 unaffected; p < 0.01). The results of the present study strengthen the evidence that patients with FHd demonstrate signs of somatosensory degradation of the hand that correlates with clinical sensorimotor dysfunction, with characteristics of the de-differentiation varying by the severity of hand dystonia. If these findings represent aberrant learning, then effective rehabilitation must incorporate the principles of neuroplasticity. Training must be individualized to each patient to rebalance the sensorimotor feedback loop and to restore normal fine motor control.

Adult↗