Neural Mechanisms Associated With Postural Control in Collegiate Soccer and Non-Soccer Athletes.

BACKGROUND AND PURPOSE: Sport-specific training may improve postural control, while repetitive head acceleration events (RHAEs) may compromise it. Understanding the neural mechanisms underlying postural control may contextualize changes due to training and RHAE. The goal of this study was to determine whether postural sway during the Balance Error Scoring System (BESS) is related to white matter organization (WMO) in collegiate athletes. METHODS: Collegiate soccer ( N = 33) and non-soccer athletes ( N = 44) completed BESS and diffusion tensor imaging. Postural sway during each BESS stance, fractional anisotropy (FA), and mean diffusivity (MD) were extracted for each participant. Partial least squares analyses determined group differences in postural sway and WMO and the relationship between postural sway and WMO in soccer and non-soccer athletes separately. RESULTS: Soccer athletes displayed better performance during BESS 6, with lower FA and higher MD in the medial lemniscus (ML) and inferior cerebellar peduncle (ICP), compared to non-soccer athletes. In soccer athletes, lower sway during BESS 2, 5, and 6 was associated with higher FA and lower MD in the corticospinal tract, ML, and ICP. In non-soccer athletes, lower sway during BESS 2 and 4 was associated with higher FA and lower MD in the ML and ICP. BESS 1 was associated with higher FA, and BESS 3 was associated with lower MD in the same tracts in non-soccer athletes. DISCUSSION AND CONCLUSIONS: Soccer and non-soccer athletes showed unique relationships between sway and WMO, suggesting that sport-specific exposures are partly responsible for changes in neurological structure and accompanying postural control performance and should be considered when evaluating postural control after injury.Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content, available at: http://links.lww.com/JNPT/A472 ).

The relation between neck strength and psychological distress: preliminary evidence from collegiate soccer athletes.

AIM: To examine whether neck strength and symmetry are associated with psychological function in athletes with exposure to repetitive head impacts. METHODS: Collegiate soccer (n = 29) and limited/noncontact (n = 63) athletes without a history of concussion completed the Brief Symptom Inventory 18 and assessments of isometric neck strength. Neck strength symmetry was calculated as the difference in strength between opposing muscle groups. RESULTS: The results demonstrated that lower neck strength was associated with more symptoms of anxiety, whereas asymmetry in neck strength was associated with more symptoms of somatization and depression in soccer athletes only. CONCLUSION: These preliminary results suggest that greater neck strength/symmetry is related to better psychological function in athletes who have higher exposure to repetitive head impacts.

Say something nice: A meta-analytic review of peer reporting interventions.

Peer reporting interventions (i.e., Positive Peer Reporting and tootling) are commonly used peer-mediated interventions in schools. These interventions involve training students to make reports about peers' prosocial behaviors, whether in oral or written form. Although peer reporting interventions have been included in meta-analyses of group contingencies, this study is the first meta-analytic review of single-case research focusing exclusively on peer reporting interventions. The literature search and application of inclusion criteria yielded 21 studies examining the impact of a peer reporting intervention on student behavior compared to baseline conditions. All studies used single-case experimental designs including at least three demonstrations of an effect and at least three data points per phase. Several aspects of studies, participants, and interventions were coded. Log response ratios and Tau were calculated as effect size estimates. Effect size estimates were synthesized in a multi-level meta-analysis with random effects for (a) studies and (b) cases within studies. Overall results indicated peer reporting interventions had a non-zero and positive impact on student outcomes. This was also true when data were subset by outcome (i.e., disruptive behavior, academically engaged behavior, and social behavior). Results were suggestive of more between- than within-study variability. Moderator analyses were conducted to identify aspects of studies, participants, or peer reporting interventions associated with differential effectiveness. Moderator analyses suggested published studies were associated with higher effect sizes than unpublished studies (i.e., theses/dissertations). This meta-analysis suggests peer reporting interventions are effective in improving student behavior compared to baseline conditions. Implications and directions for future investigation are discussed.

Relation between Isometric Neck Strength and White Matter Organization in Collegiate Athletes.

Soccer athletes frequently experience repetitive head impacts (RHI) during games and practices, which may affect neural integrity over time and lead to altered brain structure. Neck strength is hypothesized to limit the transfer of force to the brain and decrease the effect of RHI on brain structure. The goal of our work was to examine whether greater neck strength is associated with more intact white matter organization (WMO) in collegiate athletes exposed to RHI. Collegiate soccer (n = 17) and limited/non-contact sport (n = 39) athletes were assessed prior to their athletic seasons. Participants completed neck strength assessments using handheld dynamometry in six test positions and diffusion tensor imaging. Fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD), and axial diffusivity (AD) were calculated for 20 white matter (WM) regions. A multi-variate approach was used to examine the relationship between neck strength and diffusion measures in soccer and limited/non-contact athletes. Neck strength was positively associated with FA and negatively associated with RD across several WM regions in soccer players only. Neck strength was not significantly associated with MD or AD in either group. Greater neck strength was related to more intact WMO in athletes with high exposure to RHI, particularly in regions prone to damage from brain trauma such as the basal ganglia, superior longitudinal fasciculus, and frontoparietal WM. Future studies should examine neck strength as a factor to moderate neural outcomes in athletes with exposure to RHI.

Hip muscle response to a fatiguing run in females with iliotibial band syndrome.

Impaired hip muscle function has often been cited as a contributing factor to the development of iliotibial band syndrome (ITBS), yet our full understanding of this relationship is not well established. The objective of this study was to examine the effect of fatigue on hip abductor muscle function in females with ITBS. Female runners, 20 healthy and 12 with a current diagnosis of ITBS, performed a treadmill run to fatigue. Prior-to and following the run to fatigue, gluteus medius strength and median frequency values (an indicator of fatigue resistance) were measured. Additionally, onset activation timing of the gluteus medius and tensor fascia latae was measured during overground running. Both healthy and injured runners demonstrated decreased gluteus medius strength following the run to fatigue (p = 0.01), but there was no interaction between groups (p = 0.78). EMG onset activation timing did not differ between groups for the gluteus medius (P = 0.19) and tensor fascia latae muscles (P = 0.52). Injured runners demonstrated decreased gluteus medius initial median frequency values suggestive of fatigue (P = 0.01). These findings suggest that the gluteus medius muscle of female runners with ITBS does not demonstrate gross strength impairments but does demonstrate less resistance to fatigue. Clinicians should consider implementation of a gluteus medius endurance training regimen into a runner's rehabilitation program.

The Potential Role of the Cervical Spine in Sports-Related Concussion: Clinical Perspectives and Considerations for Risk Reduction.

SYNOPSIS: Sports-related concussion (SRC) occurs due to biomechanical forces to the head or neck that can result in pathophysiological changes in the brain. The musculature of the cervical spine has been identified as one potential factor in reducing SRC risk as well as for underlying sex differences in SRC rates. Recent research has demonstrated that linear and rotational head acceleration, as well as the magnitude of force upon impact, is influenced by cervical spine biomechanics. Increased neck strength and girth are associated with reduced linear and rotational head acceleration during impact. Past work has also shown that overall neck strength and girth are reduced in athletes with SRC. Additionally, differences in cervical spine biomechanics are hypothesized as a critical factor underlying sex differences in SRC rates. Specifically, compared to males, females tend to have less neck strength and girth, which are associated with increased linear and rotational head acceleration. Although our ability to detect SRC has greatly improved, our ability to prevent SRC from occurring and decrease the severity of clinical outcomes postinjury is limited. However, we suggest, along with others, that cervical spine biomechanics may be a modifiable factor in reducing SRC risk. In this commentary, we review the role of the cervical spine in reducing SRC risk, and how this risk differs by sex. We discuss clinical considerations for the examination of the cervical spine and the potential clinical relevance for SRC prevention. Additionally, we provide suggestions for future research examining cervical spine properties as modifiable factors in reducing SRC risk. J Orthop Sports Phys Ther 2019;49(3):202-208. Epub 15 Jan 2019. doi:10.2519/jospt.2019.8582.

Vibrational Relaxation and Redistribution Dynamics in Ruthenium(II) Polypyridyl-Based Charge-Transfer Excited States: A Combined Ultrafast Electronic and Infrared Absorption Study.

Ultrafast time-resolved electronic and infrared absorption measurements have been carried out on a series of Ru(II) polypyridyl complexes in an effort to delineate the dynamics of vibrational relaxation in this class of charge transfer chromophores. Time-dependent density functional theory calculations performed on compounds of the form [Ru(CN-Me-bpy) x(bpy)3-x]2+ ( x = 1-3 for compounds 1-3, respectively, where CN-Me-bpy is 4,4'-dicyano-5,5'-dimethyl-2,2'-bipyridine and bpy is 2,2'-bipyridine) reveal features in their charge-transfer absorption envelopes that allow for selective excitation of the Ru(II)-(CN-Me-bpy) moiety, the lowest-energy MLCT state(s) in each compound of the series. Changes in band shape and amplitude of the time-resolved differential electronic absorption data are ascribed to vibrational cooling in the CN-Me-bpy-localized 3MLCT state with a time constant of 8 ± 3 ps in all three compounds. This conclusion was corroborated by picosecond time-resolved infrared absorption measurements; sharpening of the CN stretch in the 3MLCT excited state was observed with a time constant of 3.0 ± 1.5 ps in all three members of the series. Electronic absorption data acquired at higher temporal resolution revealed spectral modulation over the first 2 ps occurring with a time constant of τ = 170 ± 50 fs, in compound 1; corresponding effects are significantly attenuated in compound 2 and virtually absent in compound 3. We assign this feature to intramolecular vibrational redistribution (IVR) within the 3MLCT state and represents a rare example of this process being identified from time-resolved electronic absorption data for this important class of chromophores.

Exertion and pain do not alter coordination variability in runners with iliotibial band syndrome.

BACKGROUND: Iliotibial band syndrome is a common overuse running injury which results in altered mechanics. While injuries alter discrete mechanics, they may also cause a change in coordination variability, the stride-to-stride organization of runners' movement patterns. Uninjured and injured runners may experience a change in coordination variability during a run to exertion due to fatigue, pain, or a combination of these factors. The aim of the current study was to determine if runners with iliotibial band syndrome and uninjured runners display different segment coordination variability across the course of a run to exertion. METHODS: 3D kinematics were collected as 13 uninjured runners and 12 runners with iliotibial band syndrome ran on a treadmill. A modified vector coding technique was used to calculate coordination variability during stance for segment couples of interest. Coordination variability was compared between uninjured and injured runners at the beginning and end of the run. The influence of pain on coordination variability was also examined. FINDINGS: There were no differences in coordination variability at the beginning or end of the run between uninjured runners and those with iliotibial band syndrome. The change in coordination variability due to the run was not different between uninjured runners, injured runners who experienced no change in pain, and injured runners who did experience a change in pain. INTERPRETATION: Runners do not constrain the patterns of segment motion they use in response to exertion nor does it appear that occurrence of pain during running results in a differential change in coordination variability.

The effects of fatigue on lower extremity kinematics, kinetics and joint coupling in symptomatic female runners with iliotibial band syndrome.

BACKGROUND: Altered hip and knee kinematics and joint coupling have been documented in runners with iliotibial band syndrome. Symptoms often present themselves after several minutes of running, yet the effect of fatigue warrants further exploration. The purpose of this study was to determine the effect of a run to fatigue in runners with iliotibial band syndrome, as compared to healthy controls. METHODS: Twenty uninjured and 12 female runners with iliotibial band syndrome performed a treadmill run to fatigue. Prior-to and following a run to fatigue, overground running data were collected. Variables of interest included stance phase: peak hip adduction and internal rotation, peak hip abductor and external rotator joint moments and frontal-sagittal plane hip and knee joint coupling. FINDINGS: Fatigue resulted in decreased peak hip adduction angles in injured runners. Fatigue did not affect injured runners differently than controls with respect to the remaining variables. Coupling differences did not exist between healthy and injured runners with respect to the loading or propulsive phases of stance. INTERPRETATION: While clinicians often strengthen hip abductor muscles and provide gait re-training to decrease stance phase hip adduction, our results suggest that, when exerted, female runners with iliotibial band syndrome independently modify their running gait to decrease hip adduction, potentially as a result of pain. Fatigue did not have an effect on the remaining study variables. It is possible that reducing the length of the iliotibial band through minimizing hip adduction reduces pain, but the other variables examined are not sensitive to this phenomenon.

Ultrafast Electron Transfer Between Dye and Catalyst on a Mesoporous NiO Surface.

The combination of molecular dyes and catalysts with semiconductors into dye-sensitized solar fuel devices (DSSFDs) requires control of efficient interfacial and surface charge transfer between the components. The present study reports on the light-induced electron transfer processes of p-type NiO films cosensitized with coumarin C343 and a bioinspired proton reduction catalyst, [FeFe](mcbdt)(CO)6 (mcbdt = 3-carboxybenzene-1,2-dithiolate). By transient optical spectroscopy we find that ultrafast interfacial electron transfer (τ ≈ 200 fs) from NiO to the excited C343 ("hole injection") is followed by rapid (t1/2 ≈ 10 ps) and efficient surface electron transfer from C343(-) to the coadsorbed [FeFe](mcbdt)(CO)6. The reduced catalyst has a clear spectroscopic signature that persists for several tens of microseconds, before charge recombination with NiO holes occurs. The demonstration of rapid surface electron transfer from dye to catalyst on NiO, and the relatively long lifetime of the resulting charge separated state, suggests the possibility to use these systems for photocathodes on DSSFDs.

Determination of liquid-liquid critical point composition using 90

Despite over a century of characterization efforts, liquid-liquid critical point compositions are difficult to identify with good accuracy. Reported values vary up to 10% for even well-studied systems. Here, a technique is presented for high-precision determination of the critical composition of a partially miscible binary liquid system. Ninety-degree laser light-scattering intensities from single-phase samples are analyzed using an equation derived from nonclassical power laws and the pseudospinodal approximation. Results are reported for four liquid-liquid systems (aniline + hexane, isobutyric acid + water, methanol + cyclohexane, and methanol + carbon disulfide). Compared to other methods, the 90^{∘} light-scattering approach has a strong dependence on composition near the critical point, is less affected by temperature fluctuations, and is insensitive to the presence of trace impurities in the samples. Critical compositions found with 90^{∘} light scattering are precise to the parts-per-thousand level and show long-term reproducibility.

The effect of a cadence retraining protocol on running biomechanics and efficiency: a pilot study.

Many studies have documented the association between mechanical deviations from normal and the presence or risk of injury. Some runners attempt to change mechanics by increasing running cadence. Previous work documented that increasing running cadence reduces deviations in mechanics tied to injury. The long-term effect of a cadence retraining intervention on running mechanics and energy expenditure is unknown. This study aimed to determine if increasing running cadence by 10% decreases running efficiency and changes kinematics and kinetics to make them less similar to those associated with injury. Additionally, this study aimed to determine if, after 6 weeks of cadence retraining, there would be carryover in kinematic and kinetic changes from an increased cadence state to a runner's preferred running cadence without decreased running efficiency. We measured oxygen uptake, kinematic and kinetic data on six uninjured participants before and after a 6-week intervention. Increasing cadence did not result in decreased running efficiency but did result in decreases in stride length, hip adduction angle and hip abductor moment. Carryover was observed in runners' post-intervention preferred running form as decreased hip adduction angle and vertical loading rate.

Spectroelectrochemical identification of charge-transfer excited states in transition metal-based polypyridyl complexes.

Identification of transient species is a necessary part of delineating the kinetics and mechanisms associated with chemical dynamics; when dealing with photo-induced processes, this can be an exceptionally challenging task due to the fact that spectra associated with excited state(s) sampled over the course of a photochemical event often cannot be uniquely identified nor readily calculated. Using Group 8 complexes of the general form [M(terpy)2](2+) and [M(bpy)3](2+) as a platform (where terpy is 2,2':6',2''-terpyridine and bpy is 2,2'-bipyridine), we demonstrate how spectroelectrochemical measurements can serve as an effective tool for identifying spectroscopic signatures of charge-transfer excited states of transition metal-based chromophores. Formulating the metal-to-ligand charge-transfer (MLCT) excited state(s) as M(3+)-L(-), the extent to which a linear combination of the spectra of the oxidized and reduced forms of the parent complexes can be used to simulate the characteristic absorptions of MLCT-based transient species is examined. Quantitative agreement is determined to be essentially unachievable due to the fact that certain transitions associated with the optically prepared excited states are either overcompensated for in the spectroelectrochemical data, or simply cannot be replicated through electrochemical means. Despite this limitation, it is shown through several illustrative examples that this approach can still be extremely useful as a qualitative if not semi-quantitative guide for interpreting time-resolved electronic absorption data of charge-transfer compounds, particularly in the ultrafast time domain.

The effects of limb dominance and fatigue on running biomechanics.

PURPOSE: To establish whether lower extremity limb dominance has an effect on overground running mechanics. BACKGROUND: In attempts to resolve unilateral pathology, physical therapists often use the restoration of symmetry as a clinical milestone. While lower limb dominance has been shown to affect lower extremity mechanics during dynamic tasks such as jump landing, its effect on running gait is poorly understood. Further, despite the role of fatigue in running mechanics and injury, the interaction between fatigue and limb dominance has yet to be examined. METHODS: Three-dimensional kinematic and kinetic data were collected on 20 females during overground running. Data were collected prior-to and following a treadmill run to exertion. Dominant and non-dominant limb data were compared in the fresh-state using a paired t-test. A 2-way repeated-measures ANOVA was used to test for an interaction between fatigue and limb dominance. RESULTS: There were no significant differences between the kinematic or kinetic patterns of the dominant and non-dominant lower extremities during fresh-state overground running. Fatigue was not shown to interact with limb dominance. CONCLUSION: Limb dominance did not affect kinematic or kinetic side-to-side differences. Therefore, physical therapists can continue to use resolution of lower extremity symmetry as a goal of therapy without having to account for limb dominance. The lack of an interaction between fatigue and limb dominance indicates that the dominant and non-dominant limbs fatigue at a similar rate.

Long-Lived Charge Separated State in NiO-Based p-Type Dye-Sensitized Solar Cells with Simple Cyclometalated Iridium Complexes.

Three new cyclometalated iridium complexes were prepared and investigated on nanocrystalline NiO cathodes. Nanosecond transient absorption spectroscopy experiments show they present a surprisingly slow geminate charge recombination upon excitation on NiO, representing thus the first examples of simple sensitizers with such feature. These complexes were used in dye-sensitized solar cells using nanocrystalline NiO film as semiconductor. The long-lived charge separated state of these Ir complexes make them compatible with other redox mediators than I3(-)/I(-), such as a cobalt electrolyte and enable to reach significantly high open circuit voltage.

Synthesis and characterization of a high-symmetry ferrous polypyridyl complex: approaching the 5T2/3T1 crossing point for Fe(II.).

Electronic structure theory predicts that, depending on the strength of the ligand field, either the quintet ((5)T2) or triplet ((3)T1) term states can be stabilized as the lowest-energy ligand-field excited state of low-spin octahedral d(6) transition-metal complexes. The (3)T1 state is anticipated for second- and third-row metal complexes and has been established for certain first-row compounds such as [Co(CN)6](3-), but in the case of the widely studied Fe(II) ion, only the (5)T2 state has ever been documented. Herein we report that 2,6-bis(2-carboxypyridyl)pyridine (dcpp), when bound to Fe(II), presents a sufficiently strong ligand field to Fe(II) such that the (5)T2/(3)T1 crossing point of the d(6) configuration is approached if not exceeded. The electrochemical and photophysical properties of [Fe(dcpp)2](2+), in addition to being of fundamental interest, may also have important implications for solar energy conversion strategies that seek to utilize earth-abundant components.

Ru-based donor-acceptor photosensitizer that retards charge recombination in a p-type dye-sensitized solar cell.

We report on the synthesis and characterization of a donor-acceptor ruthenium polypyridyl complex as a photosensitizer for p-type dye-sensitized solar cells (DSSCs). The electrochemical, photophysical, and photovoltaic performance of two ruthenium-based photosensitizers were tested in NiO-based DSSCs; bis-(2,2'-bipyridine-4,4'-dicarboxylic acid)(2)N-(1,10-phenanthroline)-4-nitronaphthalene-1,8-dicarboximide ruthenium(II), ([Ru(dcb)(2)(NMI-phen)](PF(6))(2)) and tris-(2,2'-bipyridine-4,4'-dicarboxylic acid)(3) ruthenium(ii), [(Ru(dcb)(3))Cl(2)]. The presence of an electron-accepting group, 4-nitronaphthalene-1,8-dicarboximide (NMI), attached to the phenanthroline of [Ru(dcb)(2)(NMI-phen)](2+) resulted in long-lived charge separation between reduced [Ru(dcb)(2)(NMI-phen)](2+) and NiO valence band holes; 10-50 µs. In the reduced state for [Ru(dcb)(2)(NMI-phen)](2+), the electron localized on the distal NMI group. In tests with I(3)(-)/I(-) and Co(4,4'-di-tert-butyl-bipyridine)(3)(2+/3+) electrolytes, [Ru(dcb)(2)(NMI-phen)](2+) outperformed [Ru(dcb)(3)](2+) in solar cell efficiency in devices. A record APCE (25%) was achieved for a ruthenium photosensitizer in a p-type DSSC. Insights on photosensitizer regeneration kinetics are included.

Frequency and severity of acute rejection in live- versus cadaveric-donor renal transplants.

BACKGROUND: Live donors are an increasingly important source of kidneys for transplantation in Australia. The aim of this study was to compare the rate and severity of rejection between patients receiving kidney transplants from live versus cadaveric donors. METHODS: A retrospective analysis was undertaken of all patients receiving live-donor (n=109) and cadaveric-donor (n=389) renal transplants at our institution between April 1, 1994, and March 31, 2000. Follow-up was completed on all patients until graft loss, death, or May 31, 2001. RESULTS: The baseline characteristics of the live-donor and cadaveric groups were similar, except for recipient age (mean+/-SD, 36.3+/-15.6 vs. 44.5+/-14.4 years, respectively; P<0.001); donor age (46.1+/-11.3 vs. 36.1+/-16.4 years, P<0.001); pretransplant dialysis duration (1.36+/-2.1 vs. 3.4+/-4.4 years, P<0.001); and the proportions of patients receiving first allografts (95% vs. 88%, respectively; P<0.05), antibody induction (8% vs. 20%, P<0.01), and mycophenolate mofetil (MMF) (60% vs. 37%, P<0.001). Acute rejection was observed in 48 (44%) live-donor and 108 (28%) cadaveric transplants (P=0.001). Cadaveric donor type was independently predictive of less acute rejection both on logistic regression (adjusted odds ratio [AOR], 0.47; 95% confidence interval [CI], 0.30-0.73; P=0.001) and multivariate Cox proportional hazards model analysis (hazard ratio, 0.49; 95% CI, 0.34-0.69; P<0.001). Patients receiving cadaveric-donor transplants were also significantly less likely to receive antibody therapy for rejection (univariate, 18% vs. 9%; P=0.006; multivariate AOR, 0.45; 95% CI, -0.25-0.82; P<0.01), independent of recipient age, gender, race, transplant number, human leukocyte antigen mismatch, sensitization, induction therapy, delayed graft function, MMF use, tacrolimus or cyclosporine A use, sirolimus-everolimus use, year of transplant, donor age, or dialysis duration. However, donor type did not independently influence graft survival, immunologic graft survival, or patient survival. CONCLUSIONS: Live-donor kidney transplant recipients had a higher rate and severity of rejection and a shorter rejection-free period than cadaveric renal transplant recipients. Further consideration of the reasons for this difference and the use of alternative immunosuppressive strategies for live-donor transplants are recommended.

A single-centre experience of post-renal transplant lymphoproliferative disorder.

Post-transplant lymphoproliferative disorder (PTLD) complicates 1 to 10% of all transplantations. Previous clinicopathological studies of PTLD have been limited by small numbers, short follow-up times, outdated data, heterogeneity of pooled solid-organ transplant results, and selective inclusion of early-onset disease. We therefore undertake here a retrospective analysis and identify all cases of PTLD that complicated renal transplantation at the Princess Alexandra Hospital between 30 June 1969 and 31 May 2001. Tumour samples were subsequently retrieved for pathological review and for Epstein-Barr virus-encoded RNA in situ hybridisation (EBER-ISH). Of 2,030 renal transplantation patients, 29 (1.4%) developed PTLD after a median period of 0.5 years (range 0.1 to 23.3 years). PTLD patients were more likely to have received cyclosporine (76% versus 62%, P<0.05), tacrolimus (10% versus 2%, P<0.05) and OKT3 (28% versus 10%, P<0.01). As the burden of immunosuppression increased from dual, to triple, to OKT3 therapy, the risks of early onset, extensive-stage, polymorphic, Epstein-Barr virus (EBV)-associated and fatal PTLD progressively increased. The majority of patients presented with an extra-nodal mass (45%), were afebrile (76%), and had stage-IV disease (60%). EBER-ISH was positive in 58%. Actuarial 5-year disease-free survival was 53.7%. The independent predictors of mortality on multivariate Cox regression were polymorphic histology (HR 7.4, 95% CI 1.5-37) and an international prognostic index (IPI) >1 (HR 2.7, 95% CI 1.1-6.8). Compared with other treatments, chemotherapy was associated with higher survival rates (100% versus 18% at 3 years, P=0.0001). In conclusion, PTLD is more likely, occurs earlier, and is more often fatal, in the setting of intensive immunosuppression. Nevertheless, excellent long-term outcomes are achievable with early recognition and institution of appropriate treatment.