Cerebellar information processing in relapsing-remitting multiple sclerosis (RRMS)

Recent research has characterized the anatomical connectivity of the cortico-cerebellar system - a large and important fibre system in the primate brain. Within this system, there are reciprocal projections between the prefrontal cortex and Crus II of the cerebellar cortex, which both play important roles in the acquisition and execution of cognitive skills. Here, we propose that this system also plays a particular role in sustaining skilled cognitive performance in patients with Relapsing-Remitting Multiple Sclerosis (RRMS), in whom advancing neuropathology causes increasingly inefficient information processing. We scanned RRMS patients and closely matched healthy subjects while they performed the Paced Auditory Serial Addition Test (PASAT), a demanding test of information processing speed, and a control task. This enabled us to localize differences between conditions that change as a function of group (group-by-condition interactions). Hemodynamic activity in some patient populations with CNS pathology are not well understood and may be atypical, so we avoided analysis strategies that rely exclusively on models of hemodynamic activity derived from the healthy brain, using instead an approach that combined a 'model-free' analysis technique (Tensor Independent Component Analysis, TICA) that was relatively free of such assumptions, with a post-hoc 'model-based' approach (General Linear Model, GLM). Our results showed group-by-condition interactions in cerebellar cortical Crus II. We suggest that this area may have in role maintaining performance in working memory tasks by compensating for inefficient data transfer associated with white matter lesions in MS.

Outcomes of long bone fractures treated by open intramedullary nailing at the St. Ann's Bay Hospital, Jamaica

Between May 2001 to August 2004, 35 patients had open nailing of long bones. There were 40 fractures fixed. Of these 40 fractures, there were 25 femoral fractures, 11 were tibial fractures and 4 were humeral fractures. There were 33 (82.5%) closed fractures and 7 (17.5%) open fractures. In the group of patients with open fractures, there were two Grade I, two Grade II and three Grade IIIB. Seven (20%) patients were lost to follow-up; all of whom had closed fractures. The final analysis as it relates to complications was done using 28 patients with 32 fractures. The majority of fractures healed without significant complication. All the patients with closed fractures went on to bony union. There was one non-union and three delayed unions. There were two infections (osteomyelitis) and this was from the open fracture cohort. This represents an infection rate of 28.6% in this cohort. Two (7.0%) patients had persistent pain and one (3.6%) patient had early removal of the nail because of failure of fixation. The mean time from injury to surgery for the fractured femur was 15.5 (range 0-49) days; fractured tibia 24.4 (range 0-40), days and fractured humerus 41.5 (20-81) days. The mean hospital stay was 18.9 (range 9-37) days for patients with fractured femur; for fractured tibia, it was 20.5 (range 3-82) days and for fractured humerus, it was 22.7 (range 3-82) days. The mean postoperative stay was 4.1 (range 1-14) days for fractured femur, 4.5 (range 1-14) days for fractured tibia and 4.0 (range 1-10) days for fractured humerus. The mean time to healing (consolidation) as defined by X-rays was 5.0 (range 3-11) months for fractured femur 5.2 (range 3-11) months for tibia and 7.0 (range 6-8) months for fractured humerus.

Dynamic formation of a hot field reversed configuration with improved confinement by supersonic merging of two colliding high-β compact toroids

A hot stable field-reversed configuration (FRC) has been produced in the C-2 experiment by colliding and merging two high-β plasmoids preformed by the dynamic version of field-reversed θ-pinch technology. The merging process exhibits the highest poloidal flux amplification obtained in a magnetic confinement system (over tenfold increase). Most of the kinetic energy is converted into thermal energy with total temperature (T{i}+T{e}) exceeding 0.5 keV. The final FRC state exhibits a record FRC lifetime with flux confinement approaching classical values. These findings should have significant implications for fusion research and the physics of magnetic reconnection.

A transformation of self-discrimination response functions in accordance with the arbitrarily applicable relations of sameness, more than, and less than

In Experiment 1, 2 experimental subjects were given pretraining of nonarbitrary relations that brought their responses under the control of four contextual stimuli; same, opposite, more than, and less than. One control subject was not exposed to this pretraining. The 2 pretrained subjects and the 3rd nonpretrained subject then received training in six arbitrary relations, the following four relations being the most critical: same/A1-B1, same/A1-C1, less than/A1-B2, more than/A1-C2. All 3 subjects were then tested for seven derived relations, the following three relations being the most important: same/B1-C1, more than/B1-C2, less than/B1-B2. The 2 pretrained subjects, but not the nonpretrained subject, showed the derived relations. One of the stimuli (B1) from the relational network and two novel stimuli (X1 and X2) were then used to train three different self-discrimination responses on three complex schedules of reinforcement. That is, all 3 subjects were trained to pick X1 if they had not emitted a response, to pick B1 if they had emitted one response only, and to pick X2 if they had emitted two responses only. The 2 pretrained subjects, but not the nonpretrained subject, showed the predicted transformation of self-discrimination response functions in accordance with the relations of sameness, more than, and less than (i.e., no response, pick B2; one response only, pick C1; and two responses only, pick C2). In Experiment 2, 2 new subjects were employed, and the arbitrary relational training and testing phases were modified to control for a procedural artifact that may have contributed to the results of the first experiment. Experiment 2 replicated the findings of Experiment 1. The pattern of results support the utility of a relational frames approach to understanding derived stimulus relations.

A transfer of functions through derived arbitrary and nonarbitrary stimulus relations

During Experiments 1 and 2, subjects were trained in a series of related conditional discriminations in a matching-to-sample format (A1-B1, A1-C1 and A2-B2, A2-C2). A low-rate performance was then explicitly trained in the presence of B1, and a high-rate performance was explicitly trained in the presence of B2. The two types of schedule performance transferred to the C stimuli for all subjects in both experiments, in the absence of explicit reinforcement through equivalence (i.e., C1 = low rate and C2 = high rate). In Experiment 2, it was also shown that these discriminative functions transferred from the C1-C2 stimuli to two novel stimuli that were physically similar to the C stimuli (SC1 and SC2, respectively). For both these experiments, subjects demonstrated the predicted equivalence responding during matching-to-sample equivalence tests. In Experiments 3 and 4, the conditional discrimination training from the first two experiments was modified in that two further conditional discrimination tasks were trained (C1-D1 and C2-D2). However, for these tasks the D stimuli served only as positive comparisons, and ND1 and ND2 stimuli served as negative comparisons (i.e., C1 x ND1 and C2 x ND2). Subsequent to training, the negatively related stimuli (ND1 and ND2) did not become discriminative for the schedule performances explicitly trained in the presence of B1 and B2, respectively. Instead, the ND1 stimulus became discriminative for the schedule performance trained in the presence of B2, and ND2 became discriminative for the schedule performance trained in the presence of B1. All subjects from Experiment 4 showed that the novel stimulus SND1, which was physically similar to ND1, became discriminative for the same response pattern as that controlled by ND1. Similarly, SND2, which was physically similar to ND2, became discriminative for the same response pattern as that controlled by ND2. Subjects from both Experiments 3 and 4 also produced equivalence responding on matching-to-sample equivalence tests that corresponded perfectly to the derived performances shown on the transfer of discriminative control tests.

A transfer of self-discrimination response functions through equivalence relations

The present study tested the idea that human self-discrimination response functions may transfer through equivalence relations. Four subjects were trained in six symbolic matching-to-sample tasks (if see A1, choose B1; A1-C1, A2-B2, A2-C2, A3-B3, A3-C3) and were then tested for the formation of three equivalence relations (B1-C1, B2-C2, B3-C3). Two of the B stimuli (B1 and B2) were then used to train two different self-discrimination responses using either detailed instructions (Subjects 1 to 3) or minimal instructions (Subject 4) on two complex schedules of reinforcement (i.e., subjects were trained to pick the B1 stimulus if they had not emitted a response, and to pick the B2 stimulus if they had emitted one or more responses on the previous schedule). All 4 subjects showed the predicted transfer of self-discrimination response functions through equivalence relations (i.e., no response on the schedule, pick C1; one or more responses on the schedule, pick C2). Subjects also demonstrated this transfer when they were required to discriminate their schedule performance before exposure to the schedule (i.e., "what I intend to do"). Four control subjects were also used in the study. Two of these (Subjects 5 and 6) were not exposed to any form of matching-to-sample training and testing (nonequivalence controls). The 2 remaining subjects (7 and 8) were exposed to matching-to-sample training and testing that incorporated stimuli not used during the transfer test; C1 and C2 were replaced by N1 and N2 during the matching-to-sample training and testing, but C1 and C2 were used for the transfer tests (equivalence controls). All 4 subjects failed to produce the self-discrimination transfer performances observed with the experimental subjects.

Outcome tools used for ambulatory children with cerebral palsy: responsiveness and minimum clinically important differences

This prospective longitudinal multicenter study of ambulatory children with cerebral palsy (CP) examined changes in outcome tool score over time, tool responsiveness, and used a systematic method for defining minimum clinically important differences (MCIDs). Three hundred and eighty-one participants with CP (Gross Motor Function Classification System [GMFCS] Levels I-III; age range 4-18y, mean age 11y [SD 4y 4mo]; 265 diplegia, 116 hemiplegia; 230 males, 151 females). At baseline and follow-up at least 1 year later, Functional Assessment Questionnaire, Gross Motor Function Measure, Pediatric Quality of Life Inventory, Pediatric Outcomes Data Collection Instrument, Pediatric Functional Independence Measure, temporal-spatial gait parameters, and oxygen cost were collected. Adjusted standardized response means determined tool responsiveness for nonsurgical (n=292) and surgical (n=87) groups at GMFCS Levels I to III. Most scores reaching medium or large effect sizes were for GMFCS Level III. Nonsurgical group change scores were used to calculate MCID thresholds for ambulatory children with CP. These values were verified by examining participants who changed GMFCS levels. Tools measuring function were responsive when a change large enough to cause a change in GMFCS level occurred. MCID thresholds assess change in study populations over time, and serve as the basis for designing prospective intervention studies.

The efficacy and harm of prostaglandin analogues for IOP reduction in glaucoma patients compared to dorzolamide and brimonidine: a systematic review

AIM

To systematically review the literature on the efficacy and harm of prostaglandin analogues (PGAs) compared to brimonidine and dorzolamide in treating elevated intraocular pressure (IOP).

METHODS

Keywords were searched in major literature databases to identify relevant randomised clinical trials (RCTs) of PGAs for ophthalmic use. The study quality of RCTs was assessed using the Jadad scale. Outcomes assessed included reduction in IOP in individual patients, adverse events (AEs) and withdrawals due to AEs.

RESULTS

Eight unique RCTs evaluating a total of 1,722 individuals were included in this systematic review. Analysis did not show a significant reduction in the mean IOP from patients receiving latanoprost compared with those receiving brimonidine (WMD = -1.04; p = 0.30). On the other hand, the latanoprost group showed a significant reduction in mean IOP compared to the dorzolamide group (WMD = -2.64; p<0.00001). The number of ocular AEs (excluding hyperaemia) was significantly higher in the brimonidine group compared with the latanoprost group (RR = 0.66; p = 0.0005).

CONCLUSION

Latanoprost was found to be significantly superior to dorzolamide but not brimonidine. However, ocular adverse events were significantly fewer in latanoprost users than in brimonide users. Neither travoprost nor bimatoprost was compared to dorzolamide or brimonidine in the present literature.

Race/ethnic differences in AD survival in US Alzheimer's Disease Centers

OBJECTIVE

Survival after Alzheimer disease (AD) is poorly understood for patients of diverse race/ethnic groups. We examined whether nonwhite AD patients (African American, Latino, Asian, American Indian) had different rates of survival compared with white AD patients.

METHODS

The National Alzheimer's Coordinating Center (NACC) cataloged data from more than 30 Alzheimer's Disease Centers in the United States from 1984 to 2005. Patients aged 65 years or older with a diagnosis of possible/probable AD were included (n = 30,916). Survival was calculated using Cox proportional hazards models with a primary outcome of time to death. Secondary outcomes of this study were neuropathologic characteristics on an autopsied subsample (n = 3,017).

RESULTS

The 30,916 AD patients in the NACC were followed up for 2.4 +/- 2.9 years (mean age 77.6 +/- 6.5 years; 65% women; 19% nonwhite [12% African American, 4% Latino, 1.5% Asian, 0.5% American Indian, and 1% other]). Median survival was 4.8 years. African American and Latino AD patients had a lower adjusted hazard for mortality compared with white AD patients (African American hazard ratio [HR] 0.85, 95% CI 0.74 to 0.96; Latino HR 0.57, 95% CI 0.46 to 0.69). Asians and American Indians had similar adjusted hazards for mortality compared with white AD patients (p > 0.10 for both). African American and Latino autopsied AD patients had similar neuropathologic characteristics compared with white AD patients with similar clinical severity.

CONCLUSIONS

African American and Latino Alzheimer disease (AD) patients may have longer survival compared with white AD patients. Neuropathology findings did not explain survival differences by race. Determining the underlying factors behind survival differences may lead to longer survival for AD patients of all race/ethnic backgrounds.

Anti-tumor activity of ADH-1 in vitro and in vivo in combination with paclitaxel in ovarian cancer cell lines

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Background: ADH-1 is a novel N-cadherin (Ncad) antagonist. Ncad is a protein present on certain tumor cells and established tumor blood vessels. Its expression on tumor cells increases as they become more aggressive, invasive and metastatic, making it an important target for anti-cancer therapy. ADH-1 was well tolerated in phase I studies and demonstrated evidence of anti-tumor activity in 7 patients whose tumors expressed Ncad. Patient enrollment in two phase II single agent trials concluded at the end of 2006. We report on the anti-tumor activity of ADH-1 in combination with paclitaxel in cancer cell lines in vitro and in the A2780 (Ncad positive) ovarian xenograft model in vivo. Methods: In vitro cytotoxicity of SKOV-3 (ovarian) cells exposed to a fixed ratio of ADH-1 and paclitaxel simultaneously was evaluated by the WST-1 cell proliferation assay. In vivo anti-tumor activity of ADH-1, paclitaxel, and the combination was evaluated in the A2780 xenograft model. ADH-1 100 mg/kg was administered bid IP for 21 days and paclitaxel was administered qod IV for 5 days. Results: In vitro cytotoxicity assays evaluated for combination effects using CalcuSyn software indicated a strong synergistic effect of ADH-1 in combination with paclitaxel (CI <1). In vivo paclitaxel treatment produced a median Time to Endpoint (TTE) (tumor volume >2gm or study end at 60 day) of 32.1 days and 73% Tumor Growth Delay (TGD), compared to control (p=0.028). For the paclitaxel group, there was only one Tumor Free Survivor (TFS) and one transient Complete Responder (CR). ADH-1 produced a TTE of 16.1 and a -13% TGD (p>0.05). The combination of ADH-1 and paclitaxel produced a median TTE of 48.6 days, corresponding to 161% TGD (p<0.0016 compared to untreated controls, p<0.003 for vehicle treated, and p<0.005 compared to paclitaxel alone). The combination therapy generated durable CR in 5 animals, 1 transient CR and 2 PR. The combination therapy had similar toxicity to paclitaxel alone. Conclusions: In this ovarian cancer model, the combination of ADH-1 with paclitaxel produced a synergistic anti-tumor effect. Based in part on these encouraging pre-clinical results, a clinical program of ADH-1 in combination with chemotherapeutic agents has been initiated.

No significant financial relationships to disclose.

Determination of suitable pretreatment method for old-intermediate landfill leachate

For old-intermediate landfill leachate, the high concentrations of ammonium and low BOD/COD (B/C) ratios are the main obstacles to biological treatment. Magnesium ammonium phosphate (MAP) precipitation (struvite precipitation) and Fenton oxidation were employed as pretreatment options on this type of leachate. Results revealed that at optimum operating conditions of pH 9 and MAP ratio of 1:1:1, ammonium and COD were reduced by 97.8% from 2132 mg l(-1) to 46 mg l(-1) and by 50.0% from 4113 mg l(-1) to 2057 mg l(-1), respectively using struvite precipitation. COD was lowered by 76% and ammonium by 6.3% using Fenton oxidation at optimized conditions of H2O2 dosage of 3500 mg l(-1), Fe2+ dosage of 437.5 mg l(-1), pH 4, a mass ratio of 8 for H2O2: Fe2+ dosage and reaction time of 30 minutes. At their respective operating conditions, the B/C ratios for both pre-treatment methods were increased from 0.35 in the raw leachate to 0.66 and 0.71, for MAP precipitation and Fenton oxidation respectively, values that are suitable for biological treatment. This study shows that struvite precipitation is a suitable pretreatment option resulting in the simultaneous removal of ammonium and organic matter in old-intermediate landfill leachate.