Patient-facing, Semi-automated, solutions to enhance patient participation in measurement-based care practice standards in a tele-mental health specialty clinic for populations at higher risk for self-harm

PURPOSE

Collecting validated surveys that describe symptom severity (measurement based care) during evidence-based psychotherapy is crucial to allow a therapist to tailor the speed and intensity of treatment. COVID clinic closures mandated we create a flexible, remote system to conduct measurement-based care, which was accomplished via RedCap.

METHODS

RedCap was used to create a semi-automated workflow allowing all clinically-indicated evidence-based surveys (including the PHQ-9) to be delivered via email to patients; with results automatically sent to their provider. Importantly, indications of suicidal ideation were automatically escalated to the provider.

RESULTS

PHQ-9 completion improved, while provider burden for collecting surveys was greatly reduced; however, depending largely upon initial provider-patient 'training', overall compliance could still be significantly improved.

CONCLUSION

This workflow gave providers additional information compared to the typical telemedicine environment, and in fact, improved data collection rates over our in-person environment. However, when patients did not complete measures on their own, the burden on providers increased.

The use of an automated electronic registry for bladder cancer surveillance during the SARS-CoV-2 pandemic

Introduction:

We aimed to develop and compare the utility of an automated registry of all patients undergoing surveillance for non-muscle invasive bladder cancer (NMIBC) during the severe acute respiratory virus coronavirus 2 (SARS-CoV-2) pandemic.

Methods:

We populated an electronic register of all patients undergoing bladder tumour surveillance (July–September 2019). The computerised ‘traffic-light’ system was implemented in September 2019 marking the beginning of phase 2. The register was audited at two- and six-months intervals during phase 2 (November 2019 and April 2020). Audit of the system In April 2020 allowed review of care given during the peak of the SARS-CoV-2 pandemic in Ireland. The primary outcome variable was the number of patients who had delayed surveillance cystoscopy in each group.

Results:

A total of 278 cases were reviewed, 96 in the first cohort and 91 at both intervals of second phase. During the first phase of the audit 17 patients (17.7%) had a missed cystoscopy. Phase 2 showed a sustained decrease in the number of patients with missed surveillance, with eight (8.8%) missing their procedure in both the November and April (SARS-CoV-2) cohorts (17 v. 8, X2 = 10.76, p = 0.0004). Overall, most patients had their procedure done within the recommended time interval (245, 88%).

Conclusion:

A centralised accessible computerised registry of patients with NMIBC undergoing surveillance is superior to traditional manual surveillance methods, especially during the period of SARS-CoV-2. Going forward we aim to have all patients undergo surveillance within schedule with a long-term goal of a centralised national registry.

Level of evidence:

Level 2c: “Outcomes Research”.

Elevated stress is associated with prefrontal cortex dysfunction during a verbal memory task in women with HIV

HIV-infected women may be particularly vulnerable to verbal learning and memory deficits. One factor contributing to these deficits is high perceived stress, which is associated with prefrontal cortical (PFC) atrophy and memory outcomes sensitive to PFC function, including retrieval and semantic clustering. We examined the association between stress and PFC activation during a verbal memory task in 36 HIV-infected women from the Chicago Consortium of the Women's Interagency HIV Study (WIHS) to better understand the role of the PFC in this stress-related impairment. Participants completed standardized measures of verbal learning and memory and stress (perceived stress scale-10). We used functional magnetic resonance imaging to assess brain function while participants completed encoding and recognition phases of a verbal memory task. HIV-infected women with higher stress (scores in top tertile) performed worse on all verbal memory outcomes including strategic encoding (p < 0.05) compared to HIV-infected women with lower stress (scores in lower two tertiles). Patterns of brain activation during recognition (but not encoding) differed between women with higher vs. lower stress. During recognition, women with higher stress demonstrated greater deactivation in medial PFC and posterior cingulate cortex compared to women with lower stress (p < 0.05). Greater deactivation in medial PFC marginally related to less efficient strategic retrieval (p = 0.06). Similar results were found in analyses focusing on PTSD symptoms. Results suggest that stress might alter the function of the medial PFC in HIV-infected women resulting in less efficient strategic retrieval and deficits in verbal memory.

Prefrontal cortical volume loss is associated with stress-related deficits in verbal learning and memory in HIV-infected women

Deficits in verbal learning and memory are a prominent feature of neurocognitive function in HIV-infected women, and are associated with high levels of perceived stress. To understand the neurobiological factors contributing to this stress-related memory impairment, we examined the association between stress, verbal memory, and brain volumes in HIV-infected women. Participants included 38 HIV-infected women (Mean age=43.9years) from the Chicago Consortium of the Women's Interagency HIV Study (WIHS). Participants underwent structural magnetic resonance imaging (MRI) and completed standardized measures of verbal learning and memory and stress (Perceived Stress Scale-10; PSS-10). Brain volumes were evaluated in a priori regions of interest, including the medial temporal lobe (MTL) and prefrontal cortex (PFC). Compared to HIV-infected women with lower stress (PSS-10 scores in lower two tertiles), HIV-infected women with higher stress (scores in the top tertile), performed worse on measures of verbal learning and memory and showed smaller volumes bilaterally in the parahippocampal gyrus, superior frontal gyrus, middle frontal gyrus, and inferior frontal gyrus (p's<0.05). Reduced volumes in the inferior frontal gyrus, middle frontal gyrus, and superior frontal gyrus (all right hemisphere) were negatively associated with verbal learning and memory performance. Prefrontal cortical atrophy is associated with stress-related deficits in verbal learning and memory in HIV-infected women. The time course of these volume losses in relation to memory deficits has yet to be elucidated, but the magnitude of the volumetric differences between women with higher versus lower stress suggests a prolonged vulnerability due to chronic stress and/or early life trauma.

Impact of Cognitive Training on Balance and Gait in Older Adults

OBJECTIVES

Cognitive processing plays an important role in balance and gait and is a contributing factor to falls in older adults. This relationship may be explained by the fact that higher order cognitive functions such as executive functions are called upon while walking. The purpose of this study was to examine whether a cognitive training intervention leads to significant improvements on measures of balance and gait.

METHOD

This randomized trial tested whether cognitive training over 10 weeks improves balance and gait in older adults. Participants were randomly assigned to a computer-based cognitive training intervention or measurement-only control. Outcomes included Timed Up and Go (TUG), gait speed, and gait speed with a cognitive distraction. Data were analyzed using analysis of covariance models with change scores.

RESULTS

Participants' (N = 51) average age was 82.7 for those randomized to intervention and 81.1 for those randomized to control. After 10 weeks, intervention group participants performed significantly better than controls on the TUG. When the cohort was limited to those categorized as slow walkers (baseline 10-m walk ≥ 9 s), intervention participants performed significantly better than controls on TUG and distracted walking.

DISCUSSION

Cognitive training slows degradation of balance and improves gait while distracted, rendering it a promising approach to falls prevention.

Imaging chronic traumatic brain injury as a risk factor for neurodegeneration

Population-based studies have supported the hypothesis that a positive history of traumatic brain injury (TBI) is associated with an increased incidence of neurological disease and psychiatric comorbidities, including chronic traumatic encephalopathy, Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis. These epidemiologic studies, however, do not offer a clear definition of that risk, and leave unanswered the bounding criteria for greater lifetime risk of neurodegeneration. Key factors that likely mediate the degree of risk of neurodegeneration include genetic factors, significant premorbid and comorbid medical history (e.g. depression, multiple head injuries and repetitive subconcussive impact to the brain, occupational risk, age at injury, and severity of brain injury). However, given the often-described concerns in self-report accuracy as it relates to history of multiple TBIs, low frequency of patient presentation to a physician in the case of mild brain injuries, and challenges with creating clear distinctions between injury severities, disentangling the true risk for neurodegeneration based solely on population-based studies will likely remain elusive. Given this reality, multiple modalities and approaches must be combined to characterize who are at risk so that appropriate interventions to alter progression of neurodegeneration can be evaluated. This article presents data from a study that highlights uses of neuroimaging and areas of needed research in the link between TBI and neurodegenerative disease.

Considerations for return to work following traumatic brain injury

Population-based studies have demonstrated that a history positive for traumatic brain injury (TBI) can result in cognitive impairment, behavioral alterations, and pain. These outcomes can and do influence occupational function, can affect others in the workplace, and raise concerns about workplace safety upon re-entry to the workplace. Risk for long-term impairment and disability can in some cases be mitigated by assessment of capabilities relative to job duties, conservative return-to-work schedules, and, in some cases, interventions to support that return. For those in occupations at high risk for brain injury, including first responders, soldiers, and construction workers, the long-term risk of brain injury as a risk factor for neurodegenerative disease must and should inform increased concern for those with repeated injuries to the brain over the course of their lifetime and career. This chapter reviews the risks of TBI, considers factors that optimize functional recovery, and discusses potential interventions and factors that aid in return to the workplace.

Single centre experience of hypothermic machine perfusion of kidneys from extended criteria deceased heart-beating donors: a comparative study

INTRODUCTION

Kidneys from extended criteria donors are associated with higher rates of delayed graft function (DGF). Hypothermic machine perfusion (MP) for storage is associated with more favourable outcomes.

METHODS

A retrospective analysis was performed in 93 patients where the kidney was stored using hypothermic MP (LifePort(®)) and compared to an age-matched control group where the kidney was stored in cold static storage (CSS) using University of Wisconsin solution.

RESULTS

Median age was similar in both groups (59.2 years in MP vs 59.9 years in CSS, p = 0.5598). Mean cold storage time was 15.6 h in MP vs 17.9 h in CSS. Post transplant mean serum creatinine was as follows; MP group-144.7 μmol/L at 1 month; 138.3 μmol/L at 3 months and 129.5 μmol/L at 12 months. In the CSS group-163 μmol/L at 1 month; 154.9 μmol/L at 3 months and 140.2 μmol/L at 12 months. There was a statistically significant difference at 1 month (p = 0.0096) and 3 months (p = 0.0236). DGF was defined as the need for haemodialysis within 7 days post transplant. In the MP group, DGF occurred in 17.2 % patients with mean of 6 days (range 1-18). In the CSS group, 25.8 % patients with mean of 8.1 days (range 3-25). One-year graft survival rate was better in the MP group (97.85 vs 96.77 %).

CONCLUSION

Our experience to date recommends the use of hypothermic MP for storage of kidneys from extended criteria deceased heart-beating donors.

Crack cocaine use impairs anterior cingulate and prefrontal cortex function in women with HIV infection

Crack cocaine use is associated with impaired verbal memory in HIV-infected women more than uninfected women. To understand the neural basis for this impairment, this study examined the effects of crack cocaine use on activation of the prefrontal cortex (PFC) and strategic encoding during a verbal memory task in HIV-infected women. Three groups of HIV-infected women from the Chicago Consortium of the Women's Interagency HIV Study were compared: current users of crack cocaine (n = 10), former users of cocaine (n = 11), and women who had never used cocaine (n = 9). Participants underwent functional magnetic resonance imaging during a verbal memory task and completed a neuropsychological test of verbal memory. On the neuropsychological test, current crack users performed significantly worse than other groups on semantic clustering, a measure of strategic encoding, p < 0.05. During encoding, activation in left anterior cingulate cortex (ACC) was lower in current and former cocaine users compared to never users. During recognition, activation in bilateral PFC, specifically left dorsal medial PFC and bilateral dorsolateral PFC, was lower in current and former users compared to women who had never used cocaine. Lower activation in left dorsolateral PFC was correlated with worse performance on the recognition task, p < 0.05. The verbal learning and memory deficits associated with cocaine use in women with HIV may be partially accounted for by alterations in ACC and PFC function.

A preliminary study targeting neuronal pathways activated following environmental enrichment by resting state functional magnetic resonance imaging

We have shown that experience of transgenic mice harboring familial Alzheimer's disease (FAD)-linked AβPPswe/PS1ΔE9 in an enriched environment enhances hippocampal neurogenesis and synaptic plasticity and attenuates neuropathology. Nevertheless, the neuronal pathways activated following environmental enrichment underlying this effect are unknown. Using resting-state functional magnetic resonance imaging, we present preliminary evidence to show that transgenic mice, which had been housed in an enriched environment, show increased connectivity between CA1 and cortical areas compared to mice from standard housing. This is the first preliminary demonstration of live-activated neuronal pathways following environmental enrichment in FAD mice. Understanding the activated pathways may unravel the molecular mechanism underlying environmental enrichment-enhanced neuroplasticity in FAD.

Thalamic projection fiber integrity in de novo Parkinson disease

BACKGROUND AND PURPOSE

Postmortem studies of advanced PD have revealed disease-related pathology in the thalamus with an apparent predilection for specific thalamic nuclei. In the present study, we used DTI to investigate in vivo the microstructural integrity of 6 thalamic regions in de novo patients with PD relative to healthy controls.

MATERIALS AND METHODS

Forty subjects (20 with early stage untreated PD and 20 age- and sex-matched controls) were studied with a high-resolution DTI protocol at 3T to investigate the integrity of thalamic nuclei projection fibers. Two blinded, independent raters drew ROIs in the following 6 thalamic regions: AN, VA, VL, DM, VPL/VPM, and PU. FA values were then calculated from the projection fibers in each region.

RESULTS

FA values were reduced significantly in the fibers projecting from the AN, VA, and DM, but not the VPL/VPM and PU, in the PD group compared with the control group. In addition, there was a reduction in FA values that approached significance in the VL of patients with PD. These findings were consistent across both raters.

CONCLUSIONS

The present study provides preliminary in vivo evidence of thalamic projection fiber degeneration in de novo PD and sheds light on the extent of disrupted thalamic circuitry as a result of the disease itself.

Anatomical correlates of age-related working memory declines

Aging studies consistently show a relationship between decreased gray matter volume and decreased performance on working memory tasks. Few aging studies have investigated white matter changes in relation to functional brain changes during working memory tasks. Twenty-five younger and 25 older adults underwent anatomical magnetic resonance imaging (MRI) scans to measure gray matter volume, diffusion tensor imaging (DTI) to measure fractional anisotropy (FA) as a measure of white matter integrity, and functional magnetic resonance imaging (fMRI) while performing a working memory task. Significant increases in activation (fMRI) were seen in the left dorsal and ventral lateral prefrontal cortex with increased working memory load and with increased age (older showing greater bilateral activation). Partial correlational analyses revealed that even after controlling for age, frontal FA correlated significantly with fMRI activation during performance on the working memory task. These findings highlight the importance of white matter integrity in working memory performance associated with normal aging.

Negative emotion impacts memory for verbal discourse in pediatric bipolar disorder

OBJECTIVES

Cognitive and emotional deficits have been documented in youth with pediatric bipolar disorder (PBD); however, to date, a systematic evaluation of comprehension and memory for verbally presented information has not been conducted. The effect of emotion on comprehension and memory for verbally presented material also has not been examined. We examined whether youth with PBD have difficulty recalling the big picture (macrostructure) as well as the story details (microstructure).

METHODS

A total of 35 youth with PBD and 25 healthy controls completed an Affective Story Task. A psychological processing model allowed for the examination of both the macrostructure and microstructure of language comprehension.

RESULTS

Youth with PBD were capable of comprehending the gist of the stories and were not impaired by emotion when comprehending and remembering macrostructure. However, negative emotional material was found to proactively interfere with the encoding and recall of microstructure. Level of depression appeared to impact recall of microstructure, but not macrostructure.

CONCLUSIONS

Negatively valenced material may impair subsequent comprehension and memory for details among youth with PBD. This deficit could impact the daily functioning of these youth, as the perception of negative affect may derail aspects of successful comprehension and learning.

Input, retention, and output factors affecting adult age differences in visuospatial short-term memory

OBJECTIVES

The sources of age differences in short-term memory for spatial locations were explored in 2 experiments that examined factors related to input, to maintenance, and to output.

METHOD

In each experiment, 4 dots were presented briefly, followed after a retention interval by a probe dot, which was judged to either match or not match one of the 4 memory-set dots.

RESULTS AND DISCUSSION

Results showed that poorer performance by older adults could be attributed independently to reduced visual acuity, to less effective use of rehearsal strategies, and to differences in response biases.

GABAC receptor binding of quantum-dot conjugates of variable ligand valency

Highly fluorescent CdSe quantum dots (qdots) can serve as a platform for tethering multiple copies of a receptor-targeted ligand, affording study of how the level of multivalency affects receptor binding. We previously showed that qdots conjugated with long PEG chains terminated by muscimol, a known GABA(C) agonist, exhibit specific binding to the surface membrane of GABA(C) receptor-expressing Xenopus oocytes. The present report addresses the effect of varying the number, i.e., valency, of muscimol- (M-) terminated PEG chains attached to the qdot on binding of the resulting conjugate to GABA(C) receptors. M-PEG-qdots of differing muscimol valency were prepared by conjugating AMP-CdSe/ZnS qdots with muscimol-terminated and methylamine-terminated PEG chains in proportions designed to yield varying percentages of muscimol-terminated chains among the total approximately 150-200 chains bound to the qdot. The investigated valencies represented 0%, approximately 25%, approximately 50%, and 100% loading with muscimol (preparations termed M-PEG-qdot0, M-PEG-qdot25, M-PEG-qdot50, and M-PEG-qdot100, respectively. Binding of a given conjugate to surface membranes of GABA(C) receptor-expressing oocytes was analyzed by quantitative fluorescence microscopy following defined incubation with approximately 30 nM of the conjugate. With 5-20 min incubation, the fluorescence signal resulting from incubation with M-PEG-qdot25 exceeded, by approximately 6-fold, the fluorescence level obtained with M-PEG-qdot preparations that lacked muscimol-terminated chains (M-PEG-qdot0). M-PEG-qdot50 yielded a net signal roughly similar to that of M-PEG-qdot25, and that produced by M-PEG-qdot100 exceeded, by approximately 30-50%, those for M-PEG-qdot25 and M-PEG-qdot50. The time course of changes in oocyte surface membrane fluorescence resulting from the introduction of and removal of M-PEG-qdots in the medium bathing the oocyte indicated only a modest dependence of both binding and wash-out kinetics on muscimol valency. The results demonstrate a dependence of the binding activity of the M-PEG-qdot conjugates on muscimol valency, presumably reflecting higher GABA(C) avidity and/or affinity of the muscimol at high valency, and provide insight on the interactions of membrane receptor proteins with qdot conjugates containing multiple copies of a receptor-targeting ligand.

Procedural learning impairments identified via predictive saccades in chronic traumatic brain injury

OBJECTIVE

To characterize integrity of fronto-striatal circuitry in chronic traumatic brain injury (TBI).

BACKGROUND

Due to both direct and indirect effects, TBI is hypothesized to affect frontal and striatal function. On the basis of elegant animal, lesion, and neuroimaging literatures, oculomotor testing can provide a useful tool for in vivo assessments of neurophysiologic function. The predictive saccade paradigm in oculomotor function is well established to provide assessment of this fronto-striatal circuit.

METHODS

Sixty patients with a history of chronic TBI completed 2 specific tests of oculomotor function, including a test of reflexive visually guided saccades to assess basic oculomotor function and a predictive saccade test to assess procedural learning.

RESULTS

TBI (mild and moderate/severe) was associated with a decrease in rates of procedural learning, with degree of impairment increasing with injury severity. This was observed as a decrease in the proportion of anticipatory saccades (primary measure of learning).

CONCLUSIONS

This abnormal oculomotor performance supports the hypothesis that TBI results in chronic impairment of frontal-striatal functions proportionally to injury severity and demonstrate that oculomotor testing is sensitive to all severities of closed-head injury.

Etiologies of chronic anterior uveitis at a tertiary referral center over 35 years

PURPOSE

To describe the epidemiology of chronic anterior uveitis (CAU) at a tertiary center over 35 years.

METHODS

Data regarding etiology of CAU was collected from medical records of patients evaluated between 1973-2007. Relative frequencies of each diagnosis of CAU were calculated. Linear regression analyses were performed on the common types of CAU.

RESULTS

5970 patients were evaluated between 1973-2007; 31% carried a diagnosis of CAU. Idiopathic disease was diagnosed in 54% of patients (39 to 72% annually), ocular sarcoidosis in 14% of patients (2 to 20% annually), Fuchs heterochromic iridocyclitis (FHI) in 12% of patients (4 to 22% annually), and juvenile idiopathic arthritis (JIA) in 6% of patients (2 to 13% annually). The frequency of diagnosis of idiopathic CAU decreased over time, with no significant change for sarcoidosis, FHI or JIA. An increase in frequency of diagnosis was observed for HLA-B27-related disease and uveitis related to multiple sclerosis and inflammatory bowel disease.

CONCLUSIONS

The relative frequency of idiopathic disease has decreased over the past 35 years at our center. This may be related to an increase in the diagnosis of CAU associated with HLA-B27 positivity, inflammatory bowel disease (including family history) and multiple sclerosis. Despite the advances over the last 35 years, idiopathic disease still comprises at least 39% of our patients with CAU each year.

Increased fusiform area activation in schizophrenia during processing of spatial frequency-degraded faces, as revealed by fMRI

BACKGROUND

People with schizophrenia demonstrate perceptual organization impairments, and these are thought to contribute to their face processing difficulties.

METHOD

We examined the neural substrates of emotionally neutral face processing in schizophrenia by investigating neural activity under three stimulus conditions: faces characterized by the full spectrum of spatial frequencies, faces with low spatial frequency information removed [high spatial frequency (HSF) condition], and faces with high spatial frequency information removed [low spatial frequency (LSF) condition]. Face perception in the HSF condition is more reliant on local feature processing whereas perception in the LSF condition requires greater reliance on global form processing. Past studies of perceptual organization in schizophrenia indicate that patients perform relatively more poorly with degraded stimuli but also that, when global information is absent, patients may perform better than controls because of their relatively increased ability to initially process individual features. Therefore, we hypothesized that people with schizophrenia (n=14) would demonstrate greater face processing difficulties than controls (n=13) in the LSF condition, whereas they would demonstrate a smaller difference or superior performance in the HSF condition.

RESULTS

In a gender-discrimination task, behavioral data indicated high levels of accuracy for both groups, with a trend toward an interaction involving higher patient performance in the HSF condition and poorer patient performance in the LSF condition. Patients demonstrated greater activity in the fusiform gyrus compared to controls in both degraded conditions.

CONCLUSIONS

These data suggest that impairments in basic integration abilities may be compensated for by relatively increased activity in this region.

Neuroimaging of hypoxic-ischemic brain injury

Hypoxic-ischemic brain injury (HI-BI) is a common cause of neurological morbidity in children and adults. Recent developments in neuroimaging techniques may permit in vivo identification of the structural and functional anatomy of HI-BI, and offer opportunities for the development of neuroimaging-guided prognosis. This article provides an update on the types and possible roles of currently-available neuroimaging techniques. The applications and limitations of these techniques to the study and clinical evaluation of persons with HI-BI are discussed, and the need of further research is highlighted.

Retinal tissue oxygen tension imaging in the rat

PURPOSE

To report an imaging technique for measurement of oxygen tension (PO2) in retinal tissue and establish its feasibility for measuring retinal PO2 variations in rat eyes by adjusting the fraction of inspired oxygen (FiO2).

METHODS

A narrow laser line was projected at an angle on the retina, and phosphorescence emission was imaged after intravitreal injection of an oxygen-sensitive molecular probe. A frequency-domain approach was used for phosphorescence lifetime measurements. Retinal PO2 maps were computed from phosphorescence lifetime images, and oxygen profiles through the retinal depth were derived in rats in conditions of 10%, 21%, and 50% FiO2.

RESULTS

Retinal PO2 measurements were repeatable, and variations in outer and inner retina PO2 at different locations along the image were not significant (P>or=0.3). Maximum outer retinal PO2 obtained in 10%, 21%, and 50% FiO2 were significantly different (P<0.0001). Maximum outer retinal PO2 correlated with systemic arterial PO2 (R=0.70; P<0.0001). The slope of the outer retina PO2 profile correlated with maximum outer retinal PO2 (R=0.84; P<0.0001). Mean inner retina PO2 correlated with maximum outer retinal PO2 (R=0.88; P<0.0001).

CONCLUSIONS

A technique has been developed for quantitative mapping of retinal tissue oxygen tension with the potential to enable sequential monitoring of retinal oxygenation in health and disease.

Thalamic integrity underlies executive dysfunction in traumatic brain injury

OBJECTIVE

To quantify the effects of traumatic brain injury on integrity of thalamocortical projection fibers and to evaluate whether damage to these fibers accounts for impairments in executive function in chronic traumatic brain injury.

METHODS

High-resolution (voxel size: 0.78 mm x 0.78 mm x 3 mm(3)) diffusion tensor MRI of the thalamus was conducted on 24 patients with a history of single, closed-head traumatic brain injury (TBI) (12 each of mild TBI and moderate to severe TBI) and 12 age- and education-matched controls. Detailed neuropsychological testing with an emphasis on executive function was also conducted. Fractional anisotropy was extracted from 12 regions of interest in cortical and corpus callosum structures and 7 subcortical regions of interest (anterior, ventral anterior, ventral lateral, dorsomedial, ventral posterior lateral, ventral posterior medial, and pulvinar thalamic nuclei).

RESULTS

Relative to controls, patients with a history of brain injury showed reductions in fractional anisotropy in both the anterior and posterior corona radiata, forceps major, the body of the corpus callosum, and fibers identified from seed voxels in the anterior and ventral anterior thalamic nuclei. Fractional anisotropy from cortico-cortico and corpus callosum regions of interest did not account for significant variance in neuropsychological function. However, fractional anisotropy from the thalamic seed voxels did account for variance in executive function, attention, and memory.

CONCLUSIONS

The data provide preliminary evidence that traumatic brain injury and resulting diffuse axonal injury results in damage to the thalamic projection fibers and is of clinical relevance to cognition.

An fMRI examination of visual integration in schizophrenia

Behavioral and electrophysiological studies of schizophrenia have consistently demonstrated impairments in the integration of visual features into unified perceptual representations. Specific brain regions involved in this dysfunction, however, remain to be clarified. This study used functional Magnetic Resonance Imaging (fMRI) to examine the relative involvement of visual cortex areas (involved in form perception) and parietal and frontal regions (involved in attention), in the visual integration impairment in schizophrenia. Fourteen patients with schizophrenia and 14 healthy controls were compared on behavioral performance and data acquired via fMRI while completing a contour integration task that had previously been used to identify a visual integration deficit in schizophrenia. The schizophrenia patients demonstrated poorer visual integration than controls. Analyses of peak signal change indicated that while the groups were equivalent in area V1, the schizophrenia group demonstrated reduced signal in areas V2-V4, which are the earliest regions sensitive to global configurations of stimuli. Moreover, whereas the control group demonstrated greater recruitment of prefrontal and parietal areas during perception of integrated forms compared to random stimuli, the schizophrenia group demonstrated greater recruitment of frontal regions during perception of random stimuli. The two groups differed on brain regions involved in form perception even when they were matched on accuracy levels. The visual integration disturbance in schizophrenia involves both deficient basic visual processes (beginning as early as occipital region V2), as well as reduced feedback from visual attention regions that normally serves to amplify relevant visual representations relative to irrelevant information.

Impairments in memory and hippocampal function in HIV-positive vs HIV-negative women: a preliminary study

OBJECTIVE

Neurocognitive studies of HIV typically target executive functions dependent on frontostriatal circuitry. The integrity of medial temporal systems has received considerably less attention despite high hippocampal viral load. Studies also predominately involve HIV+ men, though HIV+ women may be at increased risk for cognitive dysfunction due to the high prevalence of psychosocial/mental health problems and lower educational attainment. Our aim was to conduct a preliminary investigation of episodic memory and its neural correlates in HIV-infected and at-risk uninfected women.

METHODS

Participants included 54 HIV+ and 12 HIV- women (mean age = 43 years; 86% African American) recruited from the Chicago site of the Women's Interagency HIV Study. Participants completed standardized tests of verbal and visual episodic memory, working memory, and executive function. A subset of 11 women also underwent functional MRI during a delayed verbal episodic memory task.

RESULTS

HIV serostatus predicted significantly lower immediate and delayed verbal episodic memory, working memory, and visual memory. Preliminary neuroimaging findings revealed group differences in bilateral hippocampal function, with HIV+ women showing decreased activation during encoding and increased activation during delayed recognition. These alterations correlated with worse episodic verbal memory.

CONCLUSIONS

Verbal episodic memory deficits are evident in HIV+ women and may be associated with hippocampal dysfunction at both encoding and retrieval.

An unusual case of cancer of the urachal remnant following repair of bladder exstrophy

INTRODUCTION

We report the first case of cancer of the urachal remnant following repair of bladder exstrophy, in a renal transplant recipient.

METHOD

A retrospective review of this clinical case and the associated literature were performed.

CONCLUSION

This unusual case highlights two very rare entities. Bladder exstrophy has an incidence of 1 in 50,000 newborns, whereas urachal cancer accounts for less than 1% of all bladder tumours.

A rare case of minimal deviation adenocarcinoma of the uterine cervix in a renal transplant recipient

INTRODUCTION

We report the first described case of minimal deviation adenocarcinoma of the uterine cervix in the setting of a female renal cadaveric transplant recipient.

MATERIALS AND METHODS

A retrospective review of this clinical case was performed.

CONCLUSION

This rare cancer represents only about 1% of all cervical adenocarcinoma.

Benign prostatic hyperplasia presenting with renal failure--what is the role for transurethral resection of the prostate (TURP)?

The aim of the study was to determine the role of transurethralresection of prostate (TURP) in normalising renal function in men presenting with obstructive renal failure secondary to benign prostatic hyperplasia. We reviewed the cases of 14 men who presented in the last 5 years with renal impairment associated with symptoms of bladder outflow obstruction and radiological evidence of obstructive uropathy. The mean serum creatinine at presentation was 632 ng/mL (range 1299 - 225). The mean age at presentation was 68.2 years (range 50 - 83 years). Duration of symptoms prior to presentation ranged between 1 - 118 months (mean 21.5 months). Following catheter insertion, all patients underwent TURP. Six of the 14 patients required dialysis prior to surgery. Histology of the resected prostate confirmed benign prostatic hypertrophy and/or hyperplasia in all cases. Patients with carcinoma of the prostate were excluded from the study. Following TURP, 2 of the 14 men (14%) failed to void spontaneously following removal of catheter - one patient performs clean self intermittent catheterization (CSIC), the other man has an in-dwelling catheter in situ. One patient died 7 months following TURP due to a myocardial infarction. However, 8 patients, (57%) remained dialysis dependent following TURP. Two of these patients have since undergone successful renal transplantation. Of the remaining 6 patients, only 3 have normal renal function with the other 3 experiencing moderately elevated serum creatinine (range 236 - 344 ng/mL). In patients presenting with renal failure due to bladder outflow obstruction, TURP restores normal voiding pattern in many cases. However renal failure due to bladder outflow obstruction tends to be more refractory and only 3 of 14 patients experienced return to normal renal function post treatment.

High-resolution diffusion tensor imaging in the substantia nigra of de novo Parkinson disease

BACKGROUND

In the midbrain of patients with Parkinson disease (PD), there is a selective loss of dopaminergic neurons in the ventrolateral and caudal substantia nigra (SN). In a mouse model of PD, investigators have administered 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and found that measures derived using diffusion tensor imaging (DTI) were correlated with the number of dopamine neurons lost following intoxication.

METHODS

Twenty-eight subjects (14 with early stage, untreated PD and 14 age- and gender-matched controls) were studied with a high-resolution DTI protocol at 3 Tesla using an eight-channel phase array coil and parallel imaging to study specific segments of degeneration in the SN. Regions of interest were drawn in the rostral, middle, and caudal SN by two blinded and independent raters.

RESULTS

Fractional anisotropy (FA) was reduced in the SN of subjects with PD compared with controls (p < 0.001). Post hoc analysis identified that reduced FA for patients with PD was greater in the caudal compared with the rostral region of interest (p < 0.00001). A receiver operator characteristic analysis in the caudal SN revealed that sensitivity and specificity were 100% for distinguishing patients with PD from healthy subjects. Findings were consistent across both raters.

CONCLUSIONS

These findings provide evidence that high resolution diffusion tensor imaging in the substantia nigra distinguishes early stage, de novo patients with Parkinson disease (PD) from healthy individuals on a patient by patient basis and has the potential to serve as a noninvasive early biomarker for PD.

An FMRI study of saccadic and smooth-pursuit eye movement control in patients with age-related macular degeneration

PURPOSE

To compare the cortical networks that underlie oculomotor function in patients with age-related macular degeneration (AMD) with those in normally sighted control subjects, using functional magnetic resonance imaging (fMRI).

METHODS

Six patients with bilateral geographic retinal atrophy due to AMD (age range, 55-83 years) were recruited for the study. The visual acuities of the patients ranged from 20/76 (0.58 logMAR) to 20/360 (1.26 logMAR). An additional six younger (age range, 22-31 years) and six older (age range, 54-78 years) normally sighted individuals were recruited as control subjects. fMRI data were acquired on a 3.0-Tesla, scanner while subjects performed visually guided saccade (VGS) and smooth-pursuit (SmP) tasks.

RESULTS

Contrasts between VGS and fixation on a stationary target identified a network of activation that included the frontal eye fields (FEFs), supplementary eye fields (SMA/SEFs), prefrontal cortex (PFC), intraparietal sulci (IPS), and the areas of the visual cortex (MT/V5, V2/V3, and V1) in control subjects and patients. A similar network was identified for comparisons between SmP and periods of fixation. Marked variability was observed in the performance of both tasks across all patients. For both tasks, the patients generally showed increased PFC and IPS activation, with decreased activation in visual cortex compared with the control subjects. The patients showed significantly increased activation of the FEFs and SMA/SEFs in the SmP task, compared with the control subjects.

CONCLUSIONS

These data suggest that performance of both eye movement tasks required greater involvement of the cortical regions generally implicated in attention and effort in patients with AMD.

Recovery of rod photoresponses in ABCR-deficient mice

PURPOSE

The ABCR protein of the rod outer segment is thought to facilitate movement of the all-trans retinal photoproduct of rhodopsin bleaching out of the disc lumen. This study was undertaken to investigate the extent to which ABCR deficiency affects the post-bleach recovery of the rod photoresponse in ABCR-deficient (abcr-/-) mice.

METHODS

Electroretinographic (ERG) a-wave responses were recorded from abcr-/- mice and two control strains. A bright probe flash was used to examine the course of rod recovery after fractional rhodopsin bleaches of approximately 10(-6), approximately 3 x 10(-5), approximately 0.03, and approximately 0.30 to approximately 0.40.

RESULTS

Dark-adapted abcr-/- mice and control animals exhibited similar normalized near-peak amplitudes of the paired-flash-ERG-derived, weak-flash response. Response recovery after approximately 10(-6) bleaching exhibited an average exponential time constant of 319, 171, and 213 ms, respectively, in the abcr-/- and the two control strains. Recovery time constants determined for approximately 3 x 10(-5) bleaching did not differ significantly among strains. However, those determined for the approximately 0.03 bleach indicated significantly faster recovery in abcr-/- mice (2.34 +/- 0.74 minutes) than in the controls (5.36 +/- 2.20 and 5.92 +/- 2.44 minutes). After approximately 0.30 to approximately 0.40 bleaching, the initial recovery in the abcr-/- mice was, on average, faster than in control mice.

CONCLUSIONS

By comparison with control animals, abcr-/- mice exhibit faster rod recovery after a bleach of approximately 0.03. The data suggest that ABCR in normal rods may directly or indirectly prolong all-trans retinal clearance from the disc lumen over a significant bleaching range, and that the essential function of ABCR may be to promote the clearance of residual amounts of all-trans retinal that remain in the discs long after bleaching.

Test of the paired-flash electroretinographic method in mice lacking b-waves

Previous studies of rod photoreceptors in vivo have employed a paired-flash electroretinographic (ERG) technique to determine rod response properties. To test whether absence versus presence of the ERG b-wave affects the photoreceptor response derived by the paired-flash method, we examined paired-flash-derived responses obtained from nob mice, a mutant strain with a defect in signal transduction between photoreceptors and ON bipolar cells that causes a lack of the b-wave. Normal littermates of the nob mice served as controls. The normalized amplitude-intensity relation of the derived response determined in nob mice at the near-peak time of 86 ms was similar to that determined for the controls. The full time course of the derived rod response was obtained for test flash strengths ranging from 0.11 to 17.38 scotopic cd s m(-2) (sc cd s m(-2)). Time-course data obtained from nob and control mice exhibited significant but generally modest differences. With saturating test flash strengths, half-recovery times for the derived response of nob versus control mice differed by approximately 60 ms or less about the combined (nob and control) average respective values. Time course data also were obtained before versus after intravitreal injection of L-2-amino-4-phosphonobutyrate (APB) (which blocks transmission from photoreceptors to depolarizing bipolar cells) and of cis 2,3-piperidine dicarboxylic acid (PDA) (which blocks transmission to OFF bipolar cells, and to horizontal, amacrine and ganglion cells). Neither APB nor PDA substantially affected derived responses obtained from nob or control mice. The results provide quantitative information on the effect of b-wave removal on the paired-flash-derived response in mouse. They argue against a substantial skewing effect of the b-wave on the paired-flash-derived response obtained in normal mice and are consistent with the notion that, to good approximation, this derived response represents the isolated flash response of the photoreceptors in both nob and normal mice.

Region of interest template for the human basal ganglia: comparing EPI and standardized space approaches

Identifying task-related activation in the basal ganglia (BG) is an important area of interest in normal motor systems and cognitive neuroscience. The purpose of this study was to compare changes in brain activation in the BG using results obtained from two different masking methods: a mask drawn in standardized space from a T1-weighted anatomical image and individual region of interest (ROI) masks drawn from each subject's echo-planar image (EPI) from different tasks with reference to the high resolution fast spin echo image of each subject. Two standardized masks were used: a mask developed in Talairach space (Basal Ganglia Human Area Template (BGHAT)) and a mask developed in Montreal Neurological Institute space (MNI mask). Ten subjects produced fingertip force pulses in five separate contraction tasks during fMRI scanning. ROIs were the left caudate, putamen, external and internal portions of the globus pallidus, and subthalamic nucleus. ANOVA revealed a similar average number of voxels in the EPI mask across tasks in each BG region. The percent signal change (PSC) was consistent within each region regardless of which mask was used. Linear regression analyses between PSC in BGHAT and EPI masks and MNI and EPI masks yielded r(2) values between 0.74-0.99 and 0.70-0.99 across regions, respectively. In conclusion, PSC in different BG ROIs can be compared across studies using these different masking methods. The masking method used does not affect the overall interpretation of results with respect to the effect of task. Use of a mask drawn in standardized space is a valid and time saving method of identifying PSC in the small nuclei of the BG.

White matter integrity and cognition in chronic traumatic brain injury: a diffusion tensor imaging study

Traumatic brain injury (TBI) is a serious public health problem. Even injuries classified as mild, the most common, can result in persistent neurobehavioural impairment. Diffuse axonal injury is a common finding after TBI, and is presumed to contribute to outcomes, but may not always be apparent using standard neuroimaging. Diffusion tensor imaging (DTI) is a more recent method of assessing axonal integrity in vivo. The primary objective of the current investigation was to characterize white matter integrity utilizing DTI across the spectrum of chronic TBI of all severities. A secondary objective was to examine the relationship between white matter integrity and cognition. Twenty mild, 17 moderate to severe TBI and 18 controls underwent DTI and neuropsychological testing. Fractional anisotropy, axial diffusivity and radial diffusivity were calculated from the DTI data. Fractional anisotropy was the primary measure of white matter integrity. Region of interest analysis included anterior and posterior corona radiata, cortico-spinal tracts, cingulum fibre bundles, external capsule, forceps minor and major, genu, body and splenium of the corpus callosum, inferior fronto-occipital fasciculus, superior longitudinal fasciculus and sagittal stratum. Cognitive domain scores were calculated from executive, attention and memory testing. Decreased fractional anisotropy was found in all 13 regions of interest for the moderate to severe TBI group, but only in the cortico-spinal tract, sagittal stratum and superior longitudinal fasciculus for the mild TBI group. White Matter Load (a measure of the total number of regions with reduced FA) was negatively correlated with all cognitive domains. Analysis of radial and axial diffusivity values suggested that all severities of TBI can result in a degree of axonal damage, while irreversible myelin damage was only apparent for moderate to severe TBI. The present data emphasize that white matter changes exist on a spectrum, including mild TBI. An index of global white matter neuropathology (White Matter Load) was related to cognitive function, such that greater white matter pathology predicted greater cognitive deficits. Mechanistically, mild TBI white matter changes may be primarily due to axonal damage as opposed to myelin damage. The more severe injuries impact both. DTI provides an objective means for determining the relationship of cognitive deficits to TBI, even in cases where the injury was sustained years prior to the evaluation.

Oculomotor Function in Chronic Traumatic Brain Injury

OBJECTIVE

To characterize oculomotor function using visually guided saccade and antisaccade (AS) tasks in chronic traumatic brain injury (TBI) and assess the relationship to neuropsychologic testing.

BACKGROUND

TBI causes dysfunction of prefrontal cortex, in part by disrupting cortical and subcortical pathways, resulting in specific cognitive impairments. Oculomotor function tests provide a method of assessing the integrity of these pathways.

METHODS

Twenty mild TBI (MTBI), 17 moderate to severe TBI (M/STBI), and 19 healthy controls underwent oculomotor and neuropsychologic testing.

RESULTS

On the visually guided saccade task, the M/STBI showed longer latencies and reduced accuracy. On the AS task, which is more dependent on prefrontal cortex function, both patient groups committed more prosaccade errors than controls. On neuropsychologic testing, only the M/STBI patients were significantly impaired. Correlations were found between AS and neuropsychologic performance.

CONCLUSIONS

The M/STBI group was impaired on both oculomotor tasks and neuropsychologic testing, consistent with more global neuropathology. The MTBI group showed impaired performance primarily on the AS task, consistent with prefrontal system dysfunction. Hence, oculomotor testing is sensitive to the range of neuropathology in chronic TBI, and importantly, may be more sensitive to neuropathology in MTBI.

Binding of muscimol-conjugated quantum dots to GABAC receptors

Functionalization of highly fluorescent CdSe/ZnS core-shell nanocrystals (quantum dots, qdots) is an emerging technology for labeling cell surface proteins. We have synthesized a conjugate consisting of approximately 150-200 muscimols (a GABA receptor agonist) covalently joined to the qdot via a poly(ethylene glycol) (PEG) linker (approximately 78 ethylene glycol units) and investigated the binding of this muscimol-PEG-qdot conjugate to homomeric rho1 GABAC receptors expressed in Xenopus oocytes. GABAC receptors mediate inhibitory synaptic signaling at multiple locations in the central nervous system (CNS). Binding of the conjugate was analyzed quantitatively by determining the fluorescence intensity of the oocyte surface membrane in relation to that of the surrounding incubation medium. Upon 5- to 10-min incubation with muscimol-PEG-qdots (34 nM in qdot concentration), GABAC-expressing oocytes exhibited a fluorescent halo at the surface membrane that significantly exceeded the fluorescence of the incubation medium. This halo was absent following muscimol-PEG-qdot treatment of oocytes lacking GABAC receptors. Incubation of the oocyte with free muscimol (100 microM-5 mM), PEG-muscimol (500 microM), or GABA (100 microM - 5 mM) substantially reduced or eliminated the fluorescence halo produced by muscimol-PEG-qdots, and the removal of GABA or free muscimol led to a recovery of muscimol-PEG-qdot binding. Unconjugated qdots and PEG-qdots that lacked conjugated muscimol neither exhibited significant binding activity nor diminished the subsequent binding of muscimol-PEG-qdots. The results indicate that muscimol joined to qdots via a long-chain PEG linker exhibits specific binding activity at the ligand-binding pocket of expressed GABAC receptors, despite the presence of both the long PEG linker and the sterically bulky qdot.

Rabbit antithymocyte globulin related decrease in platelet count reduced risk of pediatric renal transplant graft thrombosis

Graft thrombosis is a serious complication in pediatric renal transplantation. We assess a potential protective effect for the decrease in platelet count associated with RATG therapy against pediatric renal transplant graft vascular thrombosis. Between January 1986 and December 1998, 120 kidney transplants were performed in 95 pediatric recipients. Patients were divided into two groups. Group 1 (n = 61), non-RATG group received cyclosporine, azathioprine and steroids, while group 2 (n = 59), RATG group, received in addition, RATG at day 1 and continued for 4-10 days postoperatively. Platelet count prior to transplant, median change in absolute platelet count at 1 and 3 days post-transplant was recorded. Graft thrombosis incidence was examined. Six grafts (5%) developed thrombosis. All were in group 1 (p = 0.028). Median pretransplant platelet count (x10(9)/L) in group 1 was 283 vs. 280 in group 2 (p = 0.921). Median decrease in absolute platelet count (x10(9)/L) from pretransplant levels at one and three days post-transplant for group 1 and 2 was 18 vs. 83 (p </= 0.001) and 39 vs. 105 (p </= 0.001), respectively. Graft thrombosis risk factors were similar in both groups. RATG use was statistically significant (p = 0.044) for reduced risk of graft thrombosis in multivariate analysis. Patients receiving RATG showed significant decrease in both platelet count and graft thrombosis incidence. A role for RATG related effect on platelet count is assumed.

Long-Term Outcome of Cadaveric Renal Transplant After Treatment of Symptomatic Lymphocele

PURPOSE

Between January 1993 and December 2002 a total of 1,289 renal transplants were performed at our institution. Symptomatic post-transplant lymphocele presenting as increased creatinine and hydronephrosis of the allograft was recorded at 0.02%. Records of the 27 patients in whom symptomatic lymphocele developed and of those who underwent contralateral kidney transplant (control group) were compared to determine the long-term effects of lymphocele formation on allograft function.

MATERIALS AND METHODS

A total of 37 procedures for the treatment of lymphocele were performed in 24 patients. Open marsupialization (12) and laparoscopic marsupialization (3) procedures were performed as primary treatments. Two patients underwent repeat open marsupialization. Aspiration and percutaneous catheter drainage were performed as a primary procedure in 7 and 1 cases, respectively. Percutaneous nephrostomy was required in 4 cases before definitive treatment.

RESULTS

The mean time to development of a lymphocele was 121 days (range 35 to 631). Symptomatic lymphocele did not require treatment in 3 patients. Of 19 patients undergoing primary marsupialization, recurrence in 2 necessitated repeat surgery. However, aspiration and percutaneous drainage proved to be definitive in only 2 cases. In total 8 patients required more than 1 procedure. At a mean followup of 63 months (SD 30.3) 21 allografts continued to function with a mean serum creatinine of 152 mumol/l (SD 67.9). In the control group 3 patients experienced graft failure and mean serum creatinine was 154 mumol/l (SD 51.9). Five patients died in the lymphocele group, 2 with functioning grafts compared to 4 deaths in the control group.

CONCLUSIONS

Surgical marsupialization is the preferred primary treatment for symptomatic lymphocele and is associated with excellent long-term allograft outcome.

Vascular complications of allograft nephrectomy

OBJECTIVES

To identify risk factors that predisposes patients to vascular complications from allograft nephrectomy and to determine the safe management of this group of patients.

DESIGN

This is a retrospective review of 1543 renal transplants performed in our institution between January 1990 and January 2002.

PATIENTS AND METHODS

During this period, 161 (10.4%) transplant nephrectomies were performed, of which we identified nine patients (5.6%) who sustained significant vascular complications.

RESULTS

Seven patients required ligation of external iliac artery for control of haemorrhage. Immediate vascular reconstructions (femoral-femoral cross-over bypass in two cases and one vein patch to an external iliac artery defect) were performed in three patients. Two patients had endovascular stenting of their external iliac artery pseudoaneurysm. No patient suffered limb loss. However, three patients died-two died from overwhelming sepsis and one patient died of an intra-cerebral haemorrhage.

CONCLUSIONS

While vascular complications associated with transplant nephrectomy are relatively rare, they are associated with a significantly poor outcome. Immediate attempts to reconstruct the vascular supply to the lower limb are associated with a high complication rate. We advocate that where possible, vascular reconstruction should be deferred and that external iliac artery ligation can be performed safely with surprisingly low limb ischaemia rate.

Event-related fMRI of category learning: Differences in classification and feedback networks

Eighteen healthy young adults underwent event-related (ER) functional magnetic resonance imaging (fMRI) of the brain while performing a visual category learning task. The specific category learning task required subjects to extract the rules that guide classification of quasi-random patterns of dots into categories. Following each classification choice, visual feedback was presented. The average hemodynamic response was calculated across the eighteen subjects to identify the separate networks associated with both classification and feedback. Random-effects analyses identified the different networks implicated during the classification and feedback phases of each trial. The regions included prefrontal cortex, frontal eye fields, supplementary motor and eye fields, thalamus, caudate, superior and inferior parietal lobules, and areas within visual cortex. The differences between classification and feedback were identified as (i) overall higher volumes and signal intensities during classification as compared to feedback, (ii) involvement of the thalamus and superior parietal regions during the classification phase of each trial, and (iii) differential involvement of the caudate head during feedback. The effects of learning were then evaluated for both classification and feedback. Early in learning, subjects showed increased activation in the hippocampal regions during classification and activation in the heads of the caudate nuclei during the corresponding feedback phases. The findings suggest that early stages of prototype-distortion learning are characterized by networks previously associated with strategies of explicit memory and hypothesis testing. However as learning progresses the networks change. This finding suggests that the cognitive strategies also change during prototype-distortion learning.

Prototype-distortion category learning: a two-phase learning process across a distributed network

This paper reviews a body of work conducted in our laboratory that applies functional magnetic resonance imaging (fMRI) to better understand the biological response and change that occurs during prototype-distortion learning. We review results from two experiments (Little, Klein, Shobat, McClure, & Thulborn, 2004; Little & Thulborn, 2005) that provide support for increasing neuronal efficiency by way of a two-stage model that includes an initial period of recruitment of tissue across a distributed network that is followed by a period of increasing specialization with decreasing volume across the same network. Across the two studies, participants learned to classify patterns of random-dot distortions (Posner & Keele, 1968) into categories. At four points across this learning process subjects underwent examination by fMRI using a category-matching task. A large-scale network, altered across the protocol, was identified to include the frontal eye fields, both inferior and superior parietal lobules, and visual cortex. As behavioral performance increased, the volume of activation within these regions first increased and later in the protocol decreased. Based on our review of this work we propose that: (i) category learning is reflected as specialization of the same network initially implicated to complete the novel task, and (ii) this network encompasses regions not previously reported to be affected by prototype-distortion learning.

Long-Term Outcome of Cadaveric Pediatric En Bloc Transplantation — A 15-Year Experience

Pediatric en bloc transplantation of infant organs into adult recipients is a recognized technique to expand the number of kidneys available for transplantation. We reviewed our experience with this technique over a 15-year period to determine the long-term outcomes. Twelve patients underwent pediatric en bloc transplantation from donors aged <4 years. All transplants functioned immediately with no graft thrombosis. Two patients died 12 and 10 years posttransplant with functioning grafts. The remaining 10 recipients experienced excellent graft function with a mean follow-up time of 73.8 months (range, 10 to 169 months) with no evidence of hyperfiltration injury. We conclude that pediatric en bloc transplantations achieve excellent long-term allograft function in selected recipients.

Correlations of cortical activation and behavior during the application of newly learned categories

Large individual differences are commonly observed during the early stages of category learning in both functional MRI (fMRI) activation maps and behavioral data. The current investigation characterizes this variability by correlating the volume of activation with behavioral performance. Healthy subjects were trained to classify patterns of random dots into categories. Training was carried out using a 4-choice categorization task with feedback. Functional MRI was performed prior to any training and then following each of 3 training sessions. The fMRI sessions involved the presentation of 3 separate paradigms which required the skill imparted by the training to determine whether two patterns of dots belonged to the same category. Contrasts between the 3 paradigms allowed the examination of the effects of training and of familiarity with the task. For fMRI performed with those materials used during training, increases in the volume of activation were observed initially. As behavioral performance continued to improve, reductions in activation were observed across regions involved in visuospatial processing and spatial attention. These reductions in activation were observed only for those materials used in training and only after high levels of performance were achieved. The magnitude of these reductions in activation correlated with each individual's own rate of learning. The present data support the observation that at least two stages of cortical activation underlie the use of newly learned categories. The first, recruitment of nearby tissue, is observed as initial increases in the volumes of activation. These initial stages of recruitment are followed by specialization across the same network which is observed as a reduction in activation with continued improvements in behavioral performance.

Listening to spoken text: adult age differences as revealed by self-paced listening

An experiment is reported in which young and older adults heard spoken narratives presented in a segment-by-segment fashion using the auditory moving window (AMW) technique. Participants were instructed to initiate the presentation of each segment at their own pace, their goal being to insure good comprehension of the main ideas of the narratives. The pattern of pause times across passages was compared for passages being heard for the first time (novel condition) or after the participants had heard the passages several times before (familiar condition). The analysis of participants' pause durations in pacing through the passages suggests that although young and older adults respond similarly at the textbase level of processing, older adults do not allocate additional resources at the start of a passage in order to develop a mental model of the narrative. This pattern differs from that typically found in reading time studies.

RABBIT ANTITHYMOCYTE GLOBULIN AS INDUCTION IMMUNOTHERAPY FOR PEDIATRIC DECEASED DONOR KIDNEY TRANSPLANTATION

PURPOSE

There is scant literature describing the long-term outcome of the use of antithymocyte globulin induction immunotherapy in pediatric deceased donor kidney transplants. We retrospectively studied the long-term results and safety of antithymocyte globulin as induction immunotherapy in all children undergoing transplantation at our institution since 1991.

MATERIALS AND METHODS

A total of 120 kidney transplants were performed in 95 patients 18 years or younger between January 1986 and December 1998. Patients were divided into 2 groups. The control group (63 patients) received cyclosporine, azathioprine and prednisolone, while the treatment group (59 patients) received rabbit antithymocyte globulin (RATG) induction immunotherapy for 6 to 10 days, combined with cyclosporine, azathioprine and prednisolone.

RESULTS

Actuarial patient survival rates at 1, 3, 5 and 10 years were 96%, 95%, 95% and 90%, respectively. Actuarial graft survival rates at 1, 3, 5 and 10 years were 76%, 69%, 64% and 49%, respectively. The 1, 3, 5 and 10-year graft survival rates in the control group were 62%, 57%, 51% and 36%, respectively, compared to 90%, 82%, 79% and 69%, respectively, in the RATG group (p = 0.001). There was a significant difference in the incidence of graft loss secondary to acute cellular rejection between the control and RATG groups (19.7% vs 3.3%, p = 0.008). There was no difference in infectious complications between the control and RATG groups (13% vs 20%, p = 0.33), and there was no case of post-transplant lymphoproliferative disorder encountered in either group.

CONCLUSIONS

The use of rabbit antithymocyte globulin in pediatric deceased donor kidney transplant recipients resulted in significant improvement in graft survival and was relatively safe.