Preliminary study of a new online and equipment-free vision screening alternative for remote and isolated community.

INTRODUCTION: Vision screening has been initiated to detect potential vision problems, paving referral pathways towards a full eye examination. Time-cost-labour practicality challenges of equipment-based vision screening have lingered for decades. Going for the highest sensitivity and specificity or opting for a pragmatic and affordable vision screening program remains a dilemma in public eye health. We aimed to report the development of a new online and equipment-free vision screening called Eye: Questionnairebased Vision Screening (EyeQVS). We also analysed the visual profile of Orang Bateq resided in a remote locality, using findings from EyeQVS, single test vision screening and full eye examination. MATERIALS AND METHODS: Multi-perspective development strategies were employed in designing EyeQVS. The questionnaire items were constructed using the working backward technique, compiling common vision disorders from the literature and face validation using expert panels. Face validation and usability assessment were performed on EyeQVS. The vision screening was carried out using EyeQVS and single test visual acuity screening method. The full eye examination included visual acuity, refraction, binocular vision and ocular health assessment. The visual profile of indigenous people (Orang Bateq) at Kampung Bengoi and Kampung Atok, Jerantut, Pahang was analysed using EyeQVS, single test visual acuity screening method and full eye examination. RESULTS: The performance of EyeQVS was affirmative in both face validation and usability. About 95% of Orang Bateq failed full eye examination, while 55% failed EyeQVS screening. None of them failed single test vision screening. Binocular disorders and dry eye problems were commonly found in Orang Bateq. EyeQVS unearthed more various vision problems compared to the single test vision screening (visual acuity alone) as a screening tool in a remote location. CONCLUSION: EyeQVS can screen for binocular disorders and dry eyes problem commonly found among indigenous people, which might be missed using a single-test visual acuity screening approach. EyeQVS is a practical alternative for vision screening in places where financial or location hinders eye healthcare access.

Organotypic brain slice cultures to model neurodegenerative proteinopathies.

Organotypic slice cultures of brain or spinal cord have been a longstanding tool in neuroscience research but their utility for understanding Alzheimer's disease (AD) and other neurodegenerative proteinopathies has only recently begun to be evaluated. Organotypic brain slice cultures (BSCs) represent a physiologically relevant three-dimensional model of the brain. BSCs support all the central nervous system (CNS) cell types and can be produced from brain areas involved in neurodegenerative disease. BSCs can be used to better understand the induction and significance of proteinopathies underlying the development and progression of AD and other neurodegenerative disorders, and in the future may serve as bridging technologies between cell culture and in vivo experiments for the development and evaluation of novel therapeutic targets and strategies. We review the initial development and general use of BSCs in neuroscience research and highlight the advantages of these cultures as an ex vivo model. Subsequently we focus on i) BSC-based modeling of AD and other neurodegenerative proteinopathies ii) use of BSCs to understand mechanisms underlying these diseases and iii) how BSCs can serve as tools to screen for suitable therapeutics prior to in vivo investigations. Finally, we will examine i) open questions regarding the use of such cultures and ii) how emerging technologies such as recombinant adeno-associated viruses (rAAV) may be combined with these models to advance translational research relevant to neurodegenerative disorders.

Antibody-mediated protection against MERS-CoV in the murine model.

Murine antisera with neutralising activity for the coronavirus causative of Middle East respiratory syndrome (MERS) were induced by immunisation of Balb/c mice with the receptor binding domain (RBD) of the viral Spike protein. The murine antisera induced were fully-neutralising in vitro for two separate clinical strains of the MERS coronavirus (MERS-CoV). To test the neutralising capacity of these antisera in vivo, susceptibility to MERS-CoV was induced in naive recipient Balb/c mice by the administration of an adenovirus vector expressing the human DPP4 receptor (Ad5-hDPP4) for MERS-CoV, prior to the passive transfer of the RBD-specific murine antisera to the transduced mice. Subsequent challenge of the recipient transduced mice by the intra-nasal route with a clinical isolate of the MERS-CoV resulted in a significantly reduced viral load in their lungs, compared with transduced mice receiving a negative control antibody. The murine antisera used were derived from mice which had been primed sub-cutaneously with a recombinant fusion of RBD with a human IgG Fc tag (RBD-Fc), adsorbed to calcium phosphate microcrystals and then boosted by the oral route with the same fusion protein in reverse micelles. The data gained indicate that this dual-route vaccination with novel formulations of the RBD-Fc, induced systemic and mucosal anti-viral immunity with demonstrated in vitro and in vivo neutralisation capacity for clinical strains of MERS-CoV.

Dual route vaccination for plague with emergency use applications.

Here, we report a dual-route vaccination approach for plague, able to induce a rapid response involving systemic and mucosal immunity, whilst also providing ease of use in those resource-poor settings most vulnerable to disease outbreaks. This novel vaccine (VypVaxDuo) comprises the recombinant F1 and V proteins in free association. VypVaxDuo has been designed for administration via a sub-cutaneous priming dose followed by a single oral booster dose and has been demonstrated to induce early onset immunity 14 days after the primary immunisation; full protective efficacy against live organism challenge was achieved in Balb/c mice exposed to 2 × 104 median lethal doses of Yersinia pestis Co92, by the sub-cutaneous route at 25 days after the oral booster immunisation. This dual-route vaccination effectively induced serum IgG and serum and faecal IgA, specific for F1 and V, which constitute two key virulence factors in Y. pestis, and is therefore suitable for further development to prevent bubonic plague and for evaluation in models of pneumonic plague. This is an essential requirement for control of disease outbreaks in areas of the world endemic for plague and is supported further by the observed exceptional stability of the primary vaccine formulation in vialled form under thermostressed conditions (40 °C for 29 weeks, and 40 °C with 75% relative humidity for 6 weeks), meaning no cold chain for storage or distribution is needed. In clinical use, the injected priming dose would be administered on simple rehydration of the dry powder by means of a dual barrel syringe, with the subsequent single booster dose being provided in an enteric-coated capsule suitable for oral self-administration.

Activity and mobility of subtilisin in low water organic media: hydration is more important than solvent dielectric.

The relationship between hydration, catalytic activity and protein dynamics was investigated for subtilisin Carlsberg in organic solvents with low water content. The organic media were cyclohexane, dichloromethane or acetonitrile, with controlled thermodynamic water activity (aw). Catalytic rate profiles showed the same dependence on aw for the three different solvents. The structural mobility of the enzyme in air and organic media was probed by proton solid-state NMR relaxation measurements. Both spin-lattice relaxation time (T1 ) and line width at half height (apparent spin-spin relaxation time (T2)) were determined for protein which was exchanged and hydrated with D2O. We found NMR relaxation was much more dependent on aw than medium identity (despite very different dielectrics) showing that enzyme hydration is the primary determinant of mobility. Results suggest that initial hydration up to aw 0.22 causes rigidification of part of the protein structure. As aw is increased further, enzyme mobility is found to increase. Above aw 0.44, a large increase in the proportion of more mobile protons coincides with a steep rise in catalytic activity for the enzyme in each of the solvents studied.

'Organic phase buffers' control biocatalyst activity independent of initial aqueous pH.

Combinations of triisooctylamine with its hydrochloride, or of triphenylacetic acid with its Na+ salt, can function as buffers for use during biocatalysis in organic media. They can control the pH of an adjacent aqueous phase, even though both forms of each buffer remain in the organic phase. With 0.1 M aqueous NaCl, the mid-point pH values obtained with the two buffer systems are around pH 4.5 and 7.0, respectively. The activity of an immobilized subtilisin Carlsberg shows a strong dependence on the ratio of the two forms of the triphenylacetic acid buffer system. Without the buffer, the rate shows the normal dependence on the pH of the aqueous solution before drying; however, this is almost eliminated if the buffer is used. The amine buffer system can similarly affect the activity of an immobilized Rhizomucor miehei lipase.

Neurocognitive development of children after a cerebellar tumor in infancy: A longitudinal study.

PURPOSE: To assess the long-term neuropsychologic effects experienced by children who have tumors in the cerebellum that are diagnosed and treated during infancy. PATIENTS AND METHODS: Twenty-seven children with posterior fossa tumors diagnosed at less than 36 months of age were assessed prospectively with a comprehensive set of age-appropriate tests. Group means and SDs are reported for assessments conducted at diagnosis (analysis 1) and at the most recent follow-up appointment (analysis 2). Cognitive developmental growth curves were derived from the prospective data (analysis 3) using mixed model regression analyses and controlling for age at diagnosis and socioeconomic status. RESULTS: In the first analysis, eight of 11 infants at diagnosis scored within normal limits on all neuropsychologic domains, except for motor skills, which were impaired. In the second analysis, mean scores at the most recent follow-up of 21 of 27 patients were mostly in the normal range; however, group comparisons between those who had (n = 7) and had not (n = 14) been treated with cranial radiation therapy (CRT) showed that patients in the irradiated (CRT) group scored significantly lower than those in the nonirradiated (No-CRT) group on verbal intelligence quotient (IQ) and in the motor domain. In the third analysis (growth curves of CRT and No-CRT groups), statistically significant differences in slope were found on verbal IQ, performance IQ, perceptual-motor skills, language, and attention/executive skills. Slopes on the fine-motor domain were similar; both groups declined at approximately the same rate. CONCLUSION: Neurocognitive development and outcome of children with cerebellar tumors diagnosed in infancy is very positive among those who were treated with surgery and chemotherapy. Declines in performance across time were minimal, and scores tended to remain within normal limits. By itself, a cerebellar tumor in infancy does not seem to have a significant impact on children. However, those who received CRT as part of their treatment are likely to have neurocognitive and psychosocial deficits that require remediational interventions.

Neuropsychologic effects of chemotherapy on children with cancer: a longitudinal study.

PURPOSE: A prospective study was conducted to assess the effects of chemotherapy for cancer on children's long-term neuropsychologic status. PATIENTS AND METHODS: Ninety-nine children who received no cranial radiation therapy (CRT) completed four annual neuropsychologic assessments. Fifty-one patients received intrathecal (IT) chemotherapy (ITC); 48 received no CNS treatment. These two groups were compared using repeated-measures analysis of variance on IQ, memory, language, freedom from distractibility, academic achievement, executive functions, and fine-motor, perceptual-motor, and tactile-spatial skills. In addition, 51 of the sample of 99 patients had been examined 5 to 11 years after diagnosis. Their data were analyzed to evaluate the longer-term effects of chemotherapy. The predictability of demographic and medical variables on neuropsychologic outcome at 3-year and long-term follow-up study were assessed using multiple regression techniques. RESULTS: Overall, the effects of chemotherapy in the absence of CRT appear to be slight. Patients who received ITC and intravenous (IV) methotrexate declined slightly on perceptual-motor skills, but were still well within the normal range. Both groups, regardless of treatment, declined on academic achievement tests, although not to a statistically significant degree. Age effects were found on performance IQ (PIQ) and perceptual-motor skills. Socioeconomic status (SES) correlated with a large number of variables. Sex effects were not significant. CONCLUSION: The present results are largely consistent with previous findings for nonirradiated groups. Treatment effects from ITC are slightly more apparent 5 to 11 years after diagnosis than at 3-year follow-up evaluation but this does not constitute a clinically meaningful difference. More noticeable are academic declines among all groups, regardless of treatment.

Electrophysiological response properties of spinoreticular neurons in the monkey.

Extracellular recordings were made from 29 spinoreticular cells in the spinal cords of anesthetized monkeys. The cells were in either the cervical or the lumbar enlargement, and they were identified by antidromic activation from the medial part of the pontomedullary reticular formation. More spinoreticular neurons were sampled in the cervical than in the lumbar cord. Most of the cells were contralateral to the side from which antidromic activation was observed, but a higher proportion of the spinoreticular neurons in the cervical enlargement than in the lumbar enlargement was ipsilateral to the antidromic stimulus. Three cells in the lumbar cord were antidromically activated not only from the reticular formation but also from the contralateral thalamus, confirming that some spinoreticular projections are formed by collaterals from spinothalamic cells. Most of the spinoreticular neurons were in the ventral horn in laminae VII and VIII, although a few were in laminae IV-VI. Nearly half of the spinoreticular cells in the sample could not be activated by any form of peripheral stimulation tested. The other cells could be activated by stimulation of receptive fields that varied from small to large, that were sometimes bilateral regions of the skin or deep tissues. Although some spinoreticular cells could be classified as low threshold or wide dynamic range, the largest proportion were high threshold, requiring noxious stimulation for their activation. Descending volleys resulting from stimulation in the reticular formation could often be shown to inhibit or to excite spinoreticular neurons. It can be concluded that at least some spinoreticular neurons may play a role in nociception.

Neurophysiological basis of cognitive deficits in long-term survivors of childhood cancer.

Thirty-three survivors of childhood cancer were tested with event-related potentials (P300), motor reaction time tests, and neuropsychological tests to assess the underlying physiological basis of treatment-related cognitive sequelae. Thirteen patients had received intrathecal chemotherapy, 11 had received intrathecal chemotherapy plus cranial radiotherapy, and nine had been treated without any form of central nervous system therapy. Neuropsychological performance of the groups treated without cranial radiotherapy was normal, but the group given cranial radiotherapy was significantly impaired. Mean reaction time and P300 latency were somewhat slower in the group given intrathecal chemotherapy relative to the group given no central nervous system treatment, but were significantly delayed in the group given cranial radiotherapy. Correlations of reaction time and P300 latency with neuropsychological test scores were also obtained. Results suggest that slowing of cortical activity secondary to white-matter damage may underlie cognitive decline in children treated with intensive central nervous system therapies, especially cranial radiotherapy.

Evoked potential correlates of right hemisphere involvement in language recovery following stroke.

A probe evoked potentials procedure was used to assess the relative engagement of both cerebral hemispheres during a language task in the following four groups of dextral adults: left hemisphere (LH)-damaged aphasics recovering from stroke, dysarthrics, right hemisphere (RH)-damaged nonaphasic patients, and normal control subjects. In agreement with previous findings using the probe procedure, the present results indicate greater task-specific RH activation in recovering aphasics and, to a lesser degree, dysarthric patients and greater LH activation in both nonaphasic, RH-damaged patients and normal control subjects. On the basis of these data, we suggest that increasing participation of the nondominant hemisphere may subserve restitution of language in adults sustaining LH lesions.

Evidence for right-hemisphere involvement in recovery from aphasia.

Cortical evoked potentials and dichotic listening test scores were used to assess the extent of activation of the two cerebral hemispheres during various language tasks in a group of 21 recovering aphasics, 15 nonaphasic patients with right-hemisphere stroke, and 17 normal volunteers. In agreement with previous findings, both measures suggest greater right-hemisphere activation during language processing in the recovering aphasics than in nonaphasic patients and normal subjects. These data support the view that restitution of language entails reorganization of brain function with increased participation of the nondominant hemisphere.

Brain tumors in children with neurofibromatosis: additional neuropsychological morbidity?

Neurofibromatosis type 1 is a common autosomal dominant genetic disorder associated with numerous physical anomalies and an increased incidence of neuropsychological impairment. Tumors of the CNS occur in approximately 15% of children with neurofibromatosis, presenting additional risk for cognitive impairment. This study examines the impact of an additional diagnosis of brain tumor on the cognitive profile of children with neurofibromatosis. A comprehensive battery of neuropsychological tests was administered to 149 children with neurofibromatosis. Thirty-six of these children had a codiagnosis of brain tumor. A subset of 36 children with neurofibromatosis alone was matched with the group of children diagnosed with neurofibromatosis and brain tumor. Although mean scores of the neurofibromatosis plus brain tumor group were, in general, lower than those of the neurofibromatosis alone group, these differences were not statistically significant. Children in the neurofibromatosis plus brain tumor group who received cranial irradiation (n = 9) demonstrated weaker academic abilities than did children with brain tumor who had not received that treatment. These results suggest that neurofibromatosis is associated with impairments in cognitive functioning, but the severity of the problems is not significantly exacerbated by the codiagnosis of a brain tumor unless treatment includes cranial irradiation.

Neuropsychological significance of areas of high signal intensity on brain MRIs of children with neurofibromatosis.

Of children with neurofibromatosis (NF), 40% have a cognitive or learning impairment. Approximately 60% also have anomalous areas of high signal intensity on T2-weighted brain MRIs. The association of these hyperintensities and neuropsychological status is not fully understood. We administered a battery of neuropsychological tests and a standard clinical MRI to determine the impact of hyperintensity presence, number, and location on cognitive status in 84 children (8 to 16 years) with NF type 1. These children underwent standard clinical MRI using a GE 1.5-tesla scanner (except one child who was examined with a 1.0-tesla scanner). We conducted three types of analyses: Hyperintensity presence or absence.-Scores of children with (55%) and without hyperintensities (45%) were compared using t tests. No statistically significant differences between groups in intellectual functioning or any neuropsychological variable were found. Number of hyperintensities-The number of hyperintensity locations per child ranged from one to five (mean = 2.22). Pearson correlations revealed no significant association between the number of hyperintensities and neuropsychological performance. Location of hyperintensities-In four of the five locations studied, no statistically significant differences were found between scores of children with a hyperintensity in an area and those with one elsewhere. However, mean scores for IQ, Memory, Motor, Distractibility, and Attention domains for children with hyperintensities in the thalamus were significantly lower than scores for those with hyperintensities elsewhere. These results suggest that the simple presence or absence of hyperintensities, or their total number, is not as important as their anatomic location for detecting their relationship with neuropsychological status. Taking location into account, hyperintensities in the cerebral hemispheres, basal ganglia, brainstem, or cerebellum seem to have no impact on neuropsychological functioning, whereas hyperintensities in the thalamus do.

Brain volume in children with neurofibromatosis type 1: relation to neuropsychological status.

OBJECTIVE: To determine characteristics of brain morphology in children and adolescents with neurofibromatosis type 1 and relate these characteristics to neuropsychological functioning. BACKGROUND: Neurofibromatosis type 1 is associated with numerous CNS abnormalities and cognitive impairment. Abnormal high signal intensity visible on brain MRI, brain tumors, and macrocephaly are common. Research into links between neuroanatomic and cognitive features has been inconclusive. METHODS: Fifty-two children and adolescents with neurofibromatosis type 1 were compared with 19 control subjects on several quantitative neuroanatomic and neuropsychological measures. RESULTS: Total brain volume, especially gray matter, was significantly greater for neurofibromatosis type 1 subjects than the control subjects. Group differences in the ratio of gray matter to white matter were more prominent in younger than in older subjects. Volume of gray matter in the subjects with neurofibromatosis type 1 was related to their degree of learning disability. Corpus callosum size was significantly larger for subjects in the neurofibromatosis type 1 group, and diminished performance on measures of academic achievement and visual-spatial and motor skills were associated with greater regional corpus callosum size. CONCLUSIONS: Neuroanatomic morphology and the developmental pattern of gray matter and white matter in subjects with neurofibromatosis type 1 differed from in control subjects. Some of these differences are related to the neuropsychological status of the neurofibromatosis type 1 group. We propose that delayed developmental apoptosis results in macrocephaly and a delay in the development of appropriate neuronal connections in children with neurofibromatosis type 1. We further propose that these morphologic delays are related to the cognitive profile of neurofibromatosis type 1.

Evoked potential indices of selective hemispheric engagement in affective and phonetic tasks.

Evoked potentials (EPs) to a probe click stimulus were recorded from left and right temporal areas of dextral adults engaged in phonetic and prosodic processing of an emotionally charged tape recorded conversation. Attenuation of the probe EP amplitudes was significantly greater in the left and right hemispheres during the phonetic and prosodic tasks, respectively, indicating lateral dominance shifts depending on selective processing of linguistic vs affective cues conveyed by the same speech signals.

Cycloplegic refractions in healthy children aged 1 through 48 months.

OBJECTIVES: To provide a description of refractive errors in healthy, term-born children, aged 1 through 48 months, and to test the hypotheses that spherical equivalent becomes significantly less hyperopic and less variable with increasing age. METHODS: Following a prospective, cross-sectional design, cycloplegic retinoscopy was used to measure the refractive error in both eyes of 514 healthy, term-born children in 12 age groups. Three hundred were aged 12 months or younger. Spherical equivalent and cylindrical power and axis were analyzed as a function of age. Prediction limits for spherical equivalent were calculated. RESULTS: Spherical equivalents of right and left eyes did not differ at any age. Hyperopia declined significantly with increasing age. The variability in spherical equivalent also decreased significantly with age. Cylindrical error of 1 diopter or more was found in 25% of the children; the proportion with astigmatism was highest in infancy and then waned. Myopia and anisometropia were rare, occurring in 3% and 1% of the sample, respectively. CONCLUSIONS: Significant declines in hyperopia and variability of spherical equivalent appear to be features of emmetropization. The normal prediction limits provide guidelines against which data from individual patients can be compared.

Influence of secondary structure on the decay kinetics of fluorescent donor-acceptor labelled peptides.

Time-resolved fluorescence decays from a series of methoxynaphthalene labelled peptides in ethyl acetate were monitored over the temperature range -40 to 60 degrees C. The quenching effect of a piperidone acceptor group placed at various positions along the peptide chain relative to the fluorescent methoxynaphthalene donor was studied. In this moderately polar solvent the mechanism of quenching is most likely electron transfer, although a Dexter exchange mechanism cannot be ruled out. Both donor and acceptor moieties were covalently attached to the side-chains of glutamic acid residues. These were either placed adjacently, in the case of a dipeptide, or separated by three and six amino acids within a 12 and 15 amino-acid oligopeptide, respectively. The presence of the piperidone group resulted in a reduction in the fluorescence lifetime and a change from a simple monoexponential decay to more complex behaviour. This was found to vary reversibly with temperature and not to be caused by impurities. Modelling of the fluorescence decays was carried out using either the sum of two exponentials or a distribution of decays. For the dipeptide the best fit was a distribution while in the case of the 12-mer two clearly distinguishable populations could be observed. The results for the 15-mer were equivocal. Importantly, regardless of the fitting method used the quenching rate was found to be fastest for the 12-mer. The slower quenching rates observed for the dipeptide compared to the oligopeptides provide strong evidence that secondary structure promotes better electronic coupling between the donor and acceptor. The biexponential fluorescence behaviour for the 12 amino-acid oligopeptide is ascribed to two slowly (> 10 ns) interconverting conformational states. Comparison with circular dichroism and infrared obtained in acetonitrile indicates these two conformers are likely to be an alpha-helix and a 3(10)-helix with electronic coupling strongest in the latter case.

Phage derived peptides for targeting of doxorubicin conjugates to solid tumours.

Barriers are frequently hampering targeting of drugs and toxins to solid tumours and their microenvironment. Nano-conjugates are low molecular weight conjugates of a small drug or toxin and a targeting ligand coupled through a cleavable linker group. They offer potential advantages for tumour specific delivery in diffusion-limited situations. We have exploited fd phage-derived peptides for the targeting of low molecular weight drug conjugates to solid tumours. As a model we have chosen doxorubicin conjugates targeted to the transferrin receptor (TfR). A library of phage expressing a cyclic nona-peptide was panned against TfR. The apparent affinity of phages determined by surface plasmon resonance (SPR) increased with each cycle of the panning procedure. After five rounds approximately 80% of phages expressed the same peptide, which mediated a 30-50-fold increased receptor specific cellular uptake of the phages. The corresponding peptide was synthesised using solid phase peptide chemistry on a sulfonamide based safety catch resin. Crude mixtures of the peptide, as well as transferrin itself, were able to inhibit the phage uptake significantly. The doxorubicin conjugate of the peptide containing a cleavable linker was prepared and endosomal uptake confirmed by fluorescence microscopy.

Electrophysiological evidence of the neurotoxic effects of apamin on auditory function in the rat.

Brainstem auditory evoked potentials (BAEPs) were recorded from rats before and after injection with apamin, a polypeptide component of bee venom. Increased absolute and interpeak latencies were found in Peaks III-VII of the BAEP beginning about 30 minutes after apamin injection suggesting impaired auditory function. No change in BAEP was found when animals were injected with saline or during the baseline period before apamin administration. Results corroborate recent findings from our laboratories of decreased glucose metabolism in brainstem nuclei of the auditory system [3] after injection with the same dose of apamin.