Asymmetrical lateral ventricular enlargement in Parkinson's disease

BACKGROUND

A recent case report suggested the presence of asymmetrical lateral ventricular enlargement associated with motor asymmetry in Parkinson's disease (PD). The current study explored these associations further.

METHODS

Magnetic resonance imaging (3T) scans were obtained on 17 PD and 15 healthy control subjects at baseline and 12-43 months later. Baseline and longitudinal lateral ventricular volumetric changes were compared between contralateral and ipsilateral ventricles in PD subjects relative to symptom onset side and in controls relative to their dominant hand. Correlations between changes in ventricular volume and United Parkinson's disease rating scale motor scores (UPDRS-III) whilst on medication were determined.

RESULTS

The lateral ventricle contralateral to symptom onset side displayed a faster rate of enlargement compared to the ipsilateral (P = 0.004) in PD subjects, with no such asymmetry detected (P = 0.312) in controls. There was a positive correlation between ventricular enlargement and worsening motor function assessed by UPDRS-III scores (r = 0.96, P < 0.001).

DISCUSSION

There is asymmetrical lateral ventricular enlargement that is associated with PD motor asymmetry and progression. Further studies are warranted to investigate the underlying mechanism(s), as well as the potential of using volumetric measurements as a marker for PD progression.

Maximum entropy and the state-variable approach to macroecology

The biodiversity scaling metrics widely studied in macroecology include the species-area relationship (SAR), the scale-dependent species-abundance distribution (SAD), the distribution of masses or metabolic energies of individuals within and across species, the abundance-energy or abundance-mass relationship across species, and the species-level occupancy distributions across space. We propose a theoretical framework for predicting the scaling forms of these and other metrics based on the state-variable concept and an analytical method derived from information theory. In statistical physics, a method of inference based on information entropy results in a complete macro-scale description of classical thermodynamic systems in terms of the state variables volume, temperature, and number of molecules. In analogy, we take the state variables of an ecosystem to be its total area, the total number of species within any specified taxonomic group in that area, the total number of individuals across those species, and the summed metabolic energy rate for all those individuals. In terms solely of ratios of those state variables, and without invoking any specific ecological mechanisms, we show that realistic functional forms for the macroecological metrics listed above are inferred based on information entropy. The Fisher log series SAD emerges naturally from the theory. The SAR is predicted to have negative curvature on a log-log plot, but as the ratio of the number of species to the number of individuals decreases, the SAR becomes better and better approximated by a power law, with the predicted slope z in the range of 0.14-0.20. Using the 3/4 power mass-metabolism scaling relation to relate energy requirements and measured body sizes, the Damuth scaling rule relating mass and abundance is also predicted by the theory. We argue that the predicted forms of the macroecological metrics are in reasonable agreement with the patterns observed from plant census data across habitats and spatial scales. While this is encouraging, given the absence of adjustable fitting parameters in the theory, we further argue that even small discrepancies between data and predictions can help identify ecological mechanisms that influence macroecological patterns.

Quality of life after liver resection for hepatobiliary malignancies

BACKGROUND

Few prospective longitudinal studies have used a validated quality of life (QOL) instrument in patients undergoing liver resection for hepatobiliary malignancy.

METHODS

Patients undergoing liver resection for hepatobiliary tumours in a 1-year period were enrolled. The cancer-specific European Organization for Research and Treatment of Cancer core questionnaire (EORTC QLQ-C30) was completed before operation, and at 6, 12 and 36-48 months after surgery. QOL over time was analysed in relation to several clinical factors.

RESULTS

A total of 103 patients were enrolled. Patient compliance was at least 75 per cent at all stages. Most functional scales and the global QOL scale showed a non-significant trend towards deterioration at 6 months and a return to preoperative level at 12 months. Physical functioning and dyspnoea deteriorated significantly at 6 months (P = 0.020 and P = 0.004 respectively) and did not recover by 12 months (P = 0.002 and P < 0.001 respectively). Pain and fatigue showed clinically significant deterioration over 12 months, which was not statistically significant. Survivors without recurrence at 36-48 months showed better QOL than those with recurrent disease.

CONCLUSION

Major liver resection is associated with acceptable QOL outcomes, and QOL continues to improve in the long term in those without recurrence.

Radiation dose-reduction strategies for neuroradiology CT protocols

Within the past 2 decades, the number of CT examinations performed has increased almost 10-fold. This is in large part due to advances in multidetector-row CT technology, which now allows faster image acquisition and improved isotropic imaging. The increased use, along with multidetector technique, has led to a significantly increased radiation dose to the patient from CT studies. This places increased responsibility on the radiologist to ensure that CT examinations are indicated and that the "as low as reasonably achievable" concept is adhered to. Neuroradiologists are familiar with factors that affect patient dose such as pitch, milliamperes, kilovolt peak (kVp), collimation, but with increasing attention being given to dose reduction, they are looking for additional ways to further reduce the radiation associated with their CT protocols. In response to increasing concern, CT manufacturers have developed dose-reduction tools, such as dose modulation, in which the tube current is adjusted along with the CT acquisition, according to patient's attenuation. This review will describe the available techniques for reducing dose associated with neuroradiologic CT imaging protocols.

The initial development of an item bank to assess and screen for psychological distress in cancer patients

Psychological distress is a common problem among cancer patients. Despite the large number of instruments that have been developed to assess distress, their utility remains disappointing. This study aimed to use Rasch models to develop an item-bank which would provide the basis for better means of assessing psychological distress in cancer patients.An item bank was developed from eight psychological distress questionnaires using Rasch analysis to link common items. Items from the questionnaires were added iteratively with common items as anchor points and misfitting items (infit mean square >1.3) removed, and unidimensionality assessed.A total of 4914 patients completed the questionnaires providing an initial pool of 83 items. Twenty items were removed resulting in a final pool of 63 items. Good fit was demonstrated and no additional factor structure was evident from the residuals. However, there was little overlap between item locations and person measures, since items mainly targeted higher levels of distress. The Rasch analysis allowed items to be pooled and generated a unidimensional instrument for measuring psychological distress in cancer patients. Additional items are required to more accurately assess patients across the whole continuum of psychological distress.

Rasch analysis of the dimensional structure of the Hospital Anxiety and Depression Scale

The Hospital Anxiety and Depression Scale (HADS) has been used extensively in cancer patients to identify psychological distress. Reports of the factor structure and screening performance of the instrument vary. Rasch models allow an assessment of the structure of a questionnaire by identifying item fit. Removal of misfitting items may improve both the dimensionality and efficacy of screening questionnaires. A Rasch analysis of the HADS-T and subscales was used to explore the factor structure, dimensionality and screening efficacy. A total of 1855 patients completed a touchscreen version of the HADS, including 381 patients who had received a psychiatric interview (SCAN/PSE). These data were analysed using Rasch models, and the screening efficacy at identifying cases of psychological distress and anxiety and depression evaluated. The results demonstrated that the structure of the HADS-T and subscales was unidimensional. Three items from the HADS-T, and one from each of the subscales demonstrated misfit. Screening efficacy for the HADS-T and subscales was modest. However, removal of misfitting items had little impact on screening, demonstrating that items could potentially be omitted, if required. The item range covered a narrow spectrum of psychological distress, predominantly higher levels of distress. Additional items have to be added if screening for moderate to mild distress is to be improved for cancer patients.

Determination of the absolute configurations of natural products via density functional theory calculations of optical rotation, electronic circular dichroism, and vibrational circular dichroism: the cytotoxic sesquiterpene natural products quadrone, suberosenone, suberosanone, and suberosenol A acetate

The determination of the absolute configurations (ACs) of chiral molecules using the chiroptical techniques of optical rotation (OR), electronic circular dichroism (ECD), and vibrational circular dichroism (VCD) has been revolutionized by the development of density functional theory (DFT) methods for the prediction of these properties. Here, we demonstrate the significance of these advances for the stereochemical characterization of natural products. Time-dependent DFT (TDDFT) calculations of the specific rotations, [alpha](D), of four cytotoxic natural products, quadrone (1), suberosenone (2), suberosanone (3), and suberosenol A acetate (4), are used to assign their ACs. TDDFT calculations of the ECD of 1 are used to assign its AC. The VCD spectrum of 1 is reported and also used, together with DFT calculations, to assign its AC. The ACs of 1 derived from its [alpha](D), ECD, and VCD are identical and in agreement with the AC previously determined via total synthesis. The previously undetermined ACs of 2-4, derived from their [alpha](D) values, have absolute configurations of their tricyclic cores identical to that of 1. Further studies of the ACs of these molecules using ECD and, especially, VCD are recommended to establish more definitively this finding. Our studies of the OR, ECD, and VCD of quadrone are the first to utilize DFT calculations of all three properties for the determination of the AC of a chiral natural product molecule.

Development and evaluation of an instrument to assess social difficulties in routine oncology practice

PURPOSE

To develop and preliminarily evaluate a Social Difficulties Inventory (SDI) for use in oncology practice.

METHODS

Item generation from patients (n = 96), staff (n = 49) and the literature. Questions constructed and pre-tested (n = 42) resulting in a 22-item questionnaire. Psychometric evaluation (n = 271) assessed frequency of endorsement, factor structure, summated scales and construct validity followed by randomisation to criterion validity or test-retest arms.

RESULTS

Items met preset frequency of endorsement criteria. Factor analysis revealed a four-factor structure, three clearly definable, (1) Physical ability, (2) Providing for the family and (3) Contact with others, explaining 45.8% variance. Summated scales developed from these demonstrated good reliability (Cronbach's alpha > 0.7) and were used to test and confirmed construct validity. Several comparators from the Life Events and Difficulties Schedule (LEDS) and Cancer Rehabilitation Evaluation System Short Form (CARES-SF) tested criterion validity and majority agreements were moderate to good. Test-retest reliability was good with most kappa values > 0.6. One item was eliminated resulting in a 21-item questionnaire.

CONCLUSION

The SDI is relevant and easy to understand. Initial psychometric evaluation was encouraging. Ongoing work to evaluate the clinical meaning and utility of the instrument and to examine the relationships between SDI scores and clinical outcomes will provide guidance about its usefulness as an assessment tool in routine oncology practice.

A practical synthesis of Nalpha-Fmoc-L-pyrazinylalanine via Schöllkopf's chiral auxiliary

A practical, gram-scale synthesis of L-pyrazinylalanine (Paa) is described, utilizing Schöllkopf's D-valine-derived bis-lactim ether chiral auxiliary.

Salvaging legacy data: mapping an obsolete medical nomenclature to a modern one

The Veterinary Medical Database (VMDB) is a repository containing abstracts of over six million case records from 24 veterinary colleges throughout the U.S. and Canada. These case record abstracts, spanning almost 40 years, represent a valuable resource for outcomes analysis and hypothesis generation. Database records are currently encoded using the Standard Nomenclature of Veterinary Diseases and Operations (SNVDO), a precoordinated, hierarchical coding system. SNVDO has not been updated since 1977 and is outdated and inadequate to express the current state of medical knowledge. We undertook to manually map a subset of the SNVDO codes to a modern medical nomenclature, SNOMED-RT (Version 1.0), and to evaluate the quality of the resultant mappings and the acceptability of the mapping method used. We found that the distribution of frequency of use of the SNVDO codes in the VMDB records is highly skewed, with a small number of codes accounting for a large percentage of the records. We targeted our mapping efforts on that subset of codes. We found that our targeted manual mapping of the SNVDO codes to SNOMED-RT codes was feasible and produced good quality results, based on separate evaluations performed by two domain experts. However, a significant proportion of the SNVDO codes could not be mapped to a single SNOMED-RT concept, necessitating construction of multiple-code post-coordinated terms. Additionally, this manual mapping was very labor-intensive.

Computer-based quality of life questionnaires may contribute to doctor-patient interactions in oncology

It is well recognized that oncologists should consider patients' quality of life and functioning when planning and delivering anticancer treatment, but a comprehensive assessment of how a patient feels requires a thorough inquiry. A standardized measurement of patients' quality of life may support clinicians in identifying important problems for discussion during the limited time of the medical consultations. The aim of this study was to assess the feasibility of computer-administered individual quality of life measurements in oncology clinics with immediate feedback of results to clinicians and to examine the impact of the information on consultations. The study employed a prospective non-randomized design with pre-test post-test within subjects comparisons and involved three medical oncologists and 28 cancer patients receiving chemotherapy. The intervention consisted of completion of quality of life questionnaires before the consultations and informing clinicians of the results. The main outcome measures were patients' perceptions of the content of baseline and intervention consultations and satisfaction with communication. A qualitative analysis of clinicians' interviews was performed. When clinicians had the quality of life results they enquired more often about daily activities (Z= -2.71, P=0.007), emotional problems (Z= -2.11, P=0.035) and work related issues (Z= -1.89, P=0.058). There was an increase in the number of issues discussed during the intervention consultation (Z= -1.89, P=0.059). Patients were highly satisfied with both consultations. The computer measurement was well accepted by patients who felt that the questionnaires were a useful tool to tell the doctors about their problems. The clinicians perceived that the quality of life data broadened the range of the clinical inquiry and helped them identify issues for discussion. Having symptoms and functional problems expressed quantitatively on a scale was useful for detection of change over time.

Pre- and postsynaptic actions of ATP on neurotransmission in rat submandibular ganglia

The pre- and postsynaptic actions of exogenously applied ATP were investigated in intact and dissociated parasympathetic neurones of rat submandibular ganglia. Nerve-evoked excitatory postsynaptic potentials (EPSPs) were not inhibited by the purinergic receptor antagonists, suramin and pyridoxal-phosphate-6-azophenyl-2',4'-disulphonic acid (PPADS), or the desensitising agonist, alpha,beta-methylene ATP. In contrast, EPSPs were abolished by the nicotinic acetylcholine receptor antagonists, hexamethonium and mecamylamine. Focal application of ATP (100 microM) had no effect on membrane potential of the postsynaptic neurone or on the amplitude of spontaneous EPSPs. Taken together, these results suggest the absence of functional purinergic (P2) receptors on the postganglionic neurone in situ. In contrast, focally applied ATP (100 microM) reversibly inhibited nerve-evoked EPSPs. Similarly, bath application of the non-hydrolysable analogue of ATP, ATP gamma S, reversibly depressed EPSPs amplitude. The inhibitory effects of ATP and ATP gamma S on nerve-evoked transmitter release were antagonised by bath application of either PPADS or suramin, suggesting ATP activates a presynaptic P2 purinoceptor to inhibit acetylcholine release from preganglionic nerves in the submandibular ganglia. In acutely dissociated postganglionic neurones from rat submandibular ganglia, focal application of ATP (100 microM) evoked an inward current and subsequent excitatory response and action potential firing, which was reversibly inhibited by PPADS (10 microM). The expression of P2X purinoceptors in wholemount and dissociated submandibular ganglion neurones was examined using polyclonal antibodies raised against the extracellular domain of six P2X purinoceptor subtypes (P2X(1-6)). In intact wholemount preparations, only the P2X(5) purinoceptor subtype was found to be expressed in the submandibular ganglion neurones and no P2X immunoreactivity was detected in the nerve fibres innervating the ganglion. Surprisingly, in dissociated submandibular ganglion neurones, high levels of P2X(2) and P2X(4) purinoceptors immunoreactivity were found on the cell surface. This increase in expression of P2X(2) and P2X(4) purinoceptors in dissociated submandibular neurones could explain the increased responsiveness of the neurones to exogenous ATP. We conclude that disruption of ganglionic transmission in vivo by either nerve damage or synaptic blockade may up-regulate P2X expression or availability and alter neuronal excitability.

First generation design, synthesis, and evaluation of azepine-based cryptophycin analogues

[structure: see text] Azepine-based cryptophycin mimics (+)-4 and (+)-5 have been designed and synthesized. Biological evaluation revealed modest in vitro activity against several human tumor cell lines, thereby supporting the utility of novel scaffolds for the design and synthesis of cryptophycin analogues.

Nodulisporic acid A synthetic studies. 2. Construction of an eastern hemisphere subtarget

In this, the second of two Letters, we describe an effective assembly of (+)-4, an eastern hemisphere subtarget comprising the FGH rings of (+)-nodulisporic acid A (1) (17 steps, 9% overall yield). Central to the synthesis is a Koga three-component conjugate addition-alkylation sequence which secures the trans orientation of the vicinal quaternary methyl groups. [reaction: see text]

Lituarine synthetic studies. An efficient, stereocontrolled construction of the common c(7-19) tricyclic spiroketal fragment

A highly efficient, stereocontrolled synthesis of (+)-4, the common C(7-19) tricyclic spiroketal fragment of the lituarines A, B, and C (1-3), has been achieved. Highlights of the synthesis include a remarkably facile 6-endo cyclization to access the C(8-12) pyran ring and a kinetically controlled acid-catalyzed spiroketalization. [reaction: see text]

Nodulisporic acid A synthetic studies. 1. Overall strategy and construction of a western hemisphere subtarget

In this, the first of two Letters, we outline our overall strategy for the construction of (+)-nodulisporic acid A (1), a representative member of a new class of indole diterpenes. In addition, we describe the efficient assembly of (-)-6, an advanced western hemisphere subtarget, comprising the ABC rings of (+)-nodulisporic acid A (1). The synthesis proceeded in 9% overall yield (longest linear sequence, 11 steps), exploiting a Shibasaki-Mori tandem transmetalation-cyclization to construct ring B. [reaction: see text]

Total synthesis of (+)-phorboxazole A exploiting the Petasis-Ferrier rearrangement

A highly convergent, stereocontrolled total synthesis of the potent antiproliferative agent (+)-phorboxazole A (1) has been achieved. Highlights of the synthesis include: modified Petasis-Ferrier rearrangements for assembly of both the C(11-15) and C(22-26) cis-tetrahydropyran rings; extension of the Julia olefination to the synthesis of enol ethers; the design, synthesis, and application of a novel bifunctional oxazole linchpin; and Stille coupling of a C(28) trimethyl stannane with a C(29) oxazole triflate. The longest linear sequence leading to (+)-phorboxazole A (1) was 27 steps, with an overall yield of 3%.

Stereospecific synthesis of beta-D-allopyranosides by dihydroxylation of beta-D-erythro-2,3-dideoxyhex-2-enopyranosides

The synthesis of 4,6-O-benzylidene-beta-D-erythro-2-3-dideoxyhex-2-enopyranosides and their osmium and ruthenium catalysed dihydroxylation reactions have been investigated. These reactions have been shown, for a range of monosaccharides and a disaccharide, to proceed stereospecifically to give beta-D-allopyranosides in moderate to excellent yield.

The relationship between Taxol and (+)-discodermolide: synthetic analogs and modeling studies

BACKGROUND

During the past decade, Taxol has assumed an important role in cancer chemotherapy. The search for novel compounds with a mechanism of action similar to that of Taxol, but with greater efficacy particularly in Taxol-resistant cells, has led to the isolation of new natural products. One such compound, (+)-discodermolide, although structurally distinct from Taxol, has a similar ability to stabilize microtubules. In addition, (+)-discodermolide is active in Taxol-resistant cell lines that overexpress P-glycoprotein, the multidrug-resistant transporter. Interestingly, (+)-discodermolide demonstrates a profound enhancement of the initiation process of microtubule polymerization compared to Taxol.

RESULTS

The synthesis of (+)-discodermolide analogs exploiting our highly efficient, triply convergent approach has permitted structure-activity relationship (SAR) studies. Small changes to the (+)-discodermolide structure resulted in a dramatic decrease in the ability of all four discodermolide analogs to initiate tubulin polymerization. Two of the analogs also demonstrated a decrease in total tubulin polymerization, while a change in the olefin geometry at the C8 position produced a significant decrease in cytotoxic activity.

CONCLUSIONS

The availability of (+)-discodermolide and the analogs, and the resultant SAR analysis, have permitted an exploration of the similarities and differences between (+)-discodermolide and Taxol. Docking of the X-ray/solution structure of (+)-discodermolide into the Taxol binding site of beta-tubulin revealed two possible binding modes (models I and II). The preferred pharmacophore model (I), in which the C19 side chain of (+)-discodermolide matches with the C2 benzoyl group of Taxol and the delta-lactone ring of (+)-discodermolide overlays with the C13 side chain of Taxol, concurred with the results of the SAR analysis.

Neuropsychological analyses of impulsiveness in childhood hyperactivity

BACKGROUND

Neuropsychological analyses of impulsiveness are needed to refine assessment of attention-deficit hyperactivity disorder (ADHD).

AIMS

To investigate specific impairments in hyperactive children in a neuropsychological task battery of impulsiveness, the Maudsley Attention and Response Suppression (MARS) task battery, and to identify the neural substrates.

METHOD

Impulsiveness was assessed using different tasks of inhibitory control and time management (MARS) in 55 children with ADHD, other diagnoses and controls. Functional magnetic resonance images were obtained from adolescents with and without ADHD during three of the tasks.

RESULTS

Children with ADHD, but not psychiatric controls, were impaired on tests of response inhibition, but not of motor timing. Reduced right prefrontal activation was observed in hyperactive adolescents during higher level inhibition and delay management, but not during simple sensorimotor coordination.

CONCLUSIONS

Attention-deficit hyperactivity disorder is characterised by specific deficits in tasks of motor response inhibition, but not motor timing, and by dysfunction of frontostriatal brain regions.

Total synthesis of (-)-cylindrocyclophanes A and F exploiting the reversible nature of the olefin cross metathesis reaction

Efficient total syntheses of the C(2)-symmetric (-)-cylindrocyclophanes A and F (1a and 1f) have been achieved. The initial strategy featured the use of a common advanced intermediate to assemble in stepwise fashion the required macrocycle of 1f, exploiting in turn a Myers reductive coupling followed by ring-closing metathesis. In a second-generation strategy, a remarkable cross olefin metathesis dimerization cascade was discovered and exploited to assemble the requisite [7,7]-paracyclophane macrocycles of both 1a and 1f from dienyl monomers. The successful syntheses also featured the effective use of the Danheiser annulation to construct substrates for both the Myers reductive coupling and the metathesis dimerizations strategies. Finally, the Kowalski two-step chain homologation of esters to siloxyalkynes proved superior over the original one-step protocol.

Total synthesis of (-)-callystatin A

An effective total synthesis of (-)-callystatin A (1), member of the leptomycin family of antibiotics, has been achieved. The synthesis features Evans extended aldol methodology to construct the northern polypropionate subunit and two separate Julia olefinations to assemble the conjugated dienes. The total synthesis proceeded in 2.3% overall yield with the longest linear sequence of 15 steps.