Fixel-Based Analysis Reveals Tau-Related White Matter Changes in Early Stages of Alzheimer's Disease

Several studies have shown white matter (WM) abnormalities in Alzheimer's disease (AD) using diffusion tensor imaging (DTI). Nonetheless, robust characterization of WM changes has been challenging due to the methodological limitations of DTI. We applied fixel-based analyses (FBA) to examine microscopic differences in fiber density (FD) and macroscopic changes in fiber cross-section (FC) in early stages of AD (N = 393, 212 females). FBA was also compared with DTI, free-water corrected (FW)-DTI and diffusion kurtosis imaging (DKI). We further investigated the correlation of FBA and tensor-derived metrics with AD pathology and cognition. FBA metrics were decreased in the entire cingulum bundle, uncinate fasciculus and anterior thalamic radiations in Aβ-positive patients with mild cognitive impairment compared to control groups. Metrics derived from DKI, and FW-DTI showed similar alterations whereas WM degeneration detected by DTI was more widespread. Tau-PET uptake in medial temporal regions was only correlated with reduced FC mainly in the parahippocampal cingulum in Aβ-positive individuals. This tau-related WM alteration was also associated with impaired memory. Despite the spatially extensive between-group differences in DTI-metrics, the link between WM and tau aggregation was only revealed using FBA metrics implying high sensitivity but low specificity of DTI-based measures in identifying subtle tau-related WM degeneration. No relationship was found between amyloid load and any diffusion-MRI measures. Our results indicate that early tau-related WM alterations in AD are due to macrostructural changes specifically captured by FBA metrics. Thus, future studies assessing the effects of AD pathology in WM tracts should consider using FBA metrics.

Achromatopsia-Visual Cortex Stability and Plasticity in the Absence of Functional Cones

Purpose

Achromatopsia is a rare inherited disorder rendering retinal cone photoreceptors nonfunctional. As a consequence, the sizable foveal representation in the visual cortex is congenitally deprived of visual input, which prompts a fundamental question: is the cortical representation of the central visual field in patients with achromatopsia remapped to take up processing of paracentral inputs? Such remapping might interfere with gene therapeutic treatments aimed at restoring cone function.

Methods

We conducted a multicenter study to explore the nature and plasticity of vision in the absence of functional cones in a cohort of 17 individuals affected by autosomal recessive achromatopsia and confirmed biallelic disease-causing CNGA3 or CNGB3 mutations. Specifically, we tested the hypothesis of foveal remapping in human achromatopsia. For this purpose, we applied two independent functional magnetic resonance imaging (fMRI)-based mapping approaches, i.e. conventional phase-encoded eccentricity and population receptive field mapping, to separate data sets.

Results

Both fMRI approaches produced the same result in the group comparison of achromatopsia versus healthy controls: sizable remapping of the representation of the central visual field in the primary visual cortex was not apparent.

Conclusions

Remapping of the cortical representation of the central visual field is not a general feature in achromatopsia. It is concluded that plasticity of the human primary visual cortex is less pronounced than previously assumed. A pretherapeutic imaging workup is proposed to optimize interventions.

Associations of CSF PDGFRβ With Aging, Blood-Brain Barrier Damage, Neuroinflammation, and Alzheimer Disease Pathologic Changes

BACKGROUND AND OBJECTIVES

Injured pericytes in the neurovascular unit release platelet-derived growth factor β (PDGFRβ) into the cerebrospinal fluid (CSF). However, it is not clear how pericyte injury contributes to Alzheimer's disease (AD)-related changes and blood brain barrier (BBB) damage. We aimed to test if CSF PDGFRβ was associated with different AD- and age-associated pathological changes leading to dementia.

METHODS

PDGFRβ was measured in the CSF of 771 cognitively unimpaired (CU, n=408), mild cognitive impairment (MCI, n=175) and dementia subjects (n=188) from the Swedish BioFINDER-2 cohort. We then checked association Aβ-PET and tau-PET SUVR, APOE ε4 genotype and MRI measurements of cortical thickness, white matter lesions (WML) and cerebral blood flow (CBF). We also analysed the role of CSF PDGFRβ in the relationship between aging, BBB dysfunction (measured by CSF/plasma albumin ratio, QAlb) and neuroinflammation (i.e., CSF levels of YKL-40 and glial fibrillary acidic protein [GFAP], preferentially expressed in reactive astrocytes).

RESULTS

The cohort had a mean age of 67 years (CU=62.8, MCI=69.9, dementia=70.4) and 50.1% were male (CU=46.6%, MCI=53.7%, dementia=54.3%). Higher CSF PDGFRβ concentrations were related to higher age (b=19.1, β=0.5, 95% CI=16-22.2, p<0.001), increased CSF neuroinflammatory markers of glial activation YKL-40 (b=3.4, β=0.5, 95% CI=2.8-3.9, p<0.001) and GFAP (b=27.4, β=0.4, 95% CI=20.9-33.9, p<0.001), and worse BBB integrity measured by QAlb (b=37.4, β=0.2, 95% CI=24.9-49.9, p<0.001). Age was also associated with worse BBB integrity, and this was partly mediated by PDGFRβ and neuroinflammatory markers (16-33% of total effect). However, PDGFRβ showed no associations with APOE ε4 genotype, PET imaging of Aβ and tau pathology or MRI measures of brain atrophy and white matter lesions (p>0.05).

DISCUSSION

In summary, pericyte damage, reflected by CSF PDGFRβ, may be involved in age-related BBB disruption together with neuroinflammation, but is not related to Alzheimer-related pathological changes.

Gray matter hypoperfusion is a late pathological event in the course of Alzheimer's disease

Several studies have shown decreased cerebral blood flow (CBF) in Alzheimer's disease (AD). However, the role of hypoperfusion in the disease pathogenesis remains unclear. Combining arterial spin labeling MRI, PET, and CSF biomarkers, we investigated the associations between gray matter (GM)-CBF and the key mechanisms in AD including amyloid-β (Aβ) and tau pathology, synaptic and axonal degeneration. Further, we applied a disease progression modeling to characterize the temporal sequence of different AD biomarkers. Lower perfusion was observed in temporo-occipito-parietal cortex in the Aβ-positive cognitively impaired compared to both Aβ-negative and Aβ-positive cognitively unimpaired individuals. In participants along the AD spectrum, GM-CBF was associated with tau, synaptic and axonal dysfunction, but not Aβ in similar cortical regions. Axonal degeneration was further associated with hypoperfusion in cognitively unimpaired individuals. Disease progression modeling revealed that GM-CBF disruption Followed the abnormality of biomarkers of Aβ, tau and brain atrophy. These findings indicate that tau tangles and neurodegeneration are more closely connected with GM-CBF changes than Aβ pathology. Although subjected to the sensitivity of the employed neuroimaging techniques and the modeling approach, these findings suggest that hypoperfusion might not be an early event associated with the build-up of Aβ in preclinical phase of AD.

Structural changes to primary visual cortex in the congenital absence of cone input in achromatopsia

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Anatomy of primary visual cortex (V1) assessed with surface-based morphmetry in those with congenital achromatopsia (ACHM).

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Reduction in cortical surface area in foveal, parafoveal and paracentral representations of V1 in those with ACHM.

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In ACHM a localized thickening in the area of V1 that represents the region of retina occupied solely by cones.

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V1 changes in ACHM may limit its ability to take on normal properties if retinal function were to be restored.

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Early intervention, before the development plastic period is over, may offer better restoration of vision in ACHM.

Autosomal recessive Achromatopsia (ACHM) is a rare inherited disorder associated with dysfunctional cone photoreceptors resulting in a congenital absence of cone input to visual cortex. This might lead to distinct changes in cortical architecture with a negative impact on the success of gene augmentation therapies. To investigate the status of the visual cortex in these patients, we performed a multi-centre study focusing on the cortical structure of regions that normally receive predominantly cone input. Using high-resolution T1-weighted MRI scans and surface-based morphometry, we compared cortical thickness, surface area and grey matter volume in foveal, parafoveal and paracentral representations of primary visual cortex in 15 individuals with ACHM and 42 normally sighted, healthy controls (HC). In ACHM, surface area was reduced in all tested representations, while thickening of the cortex was found highly localized to the most central representation. These results were comparable to more widespread changes in brain structure reported in congenitally blind individuals, suggesting similar developmental processes, i.e., irrespective of the underlying cause and extent of vision loss. The cortical differences we report here could limit the success of treatment of ACHM in adulthood. Interventions earlier in life when cortical structure is not different from normal would likely offer better visual outcomes for those with ACHM.

Structural Differences Across Multiple Visual Cortical Regions in the Absence of Cone Function in Congenital Achromatopsia

Most individuals with congenital achromatopsia (ACHM) carry mutations that affect the retinal phototransduction pathway of cone photoreceptors, fundamental to both high acuity vision and colour perception. As the central fovea is occupied solely by cones, achromats have an absence of retinal input to the visual cortex and a small central area of blindness. Additionally, those with complete ACHM have no colour perception, and colour processing regions of the ventral cortex also lack typical chromatic signals from the cones. This study examined the cortical morphology (grey matter volume, cortical thickness, and cortical surface area) of multiple visual cortical regions in ACHM (n = 15) compared to normally sighted controls (n = 42) to determine the cortical changes that are associated with the retinal characteristics of ACHM. Surface-based morphometry was applied to T1-weighted MRI in atlas-defined early, ventral and dorsal visual regions of interest. Reduced grey matter volume in V1, V2, V3, and V4 was found in ACHM compared to controls, driven by a reduction in cortical surface area as there was no significant reduction in cortical thickness. Cortical surface area (but not thickness) was reduced in a wide range of areas (V1, V2, V3, TO1, V4, and LO1). Reduction in early visual areas with large foveal representations (V1, V2, and V3) suggests that the lack of foveal input to the visual cortex was a major driving factor in morphological changes in ACHM. However, the significant reduction in ventral area V4 coupled with the lack of difference in dorsal areas V3a and V3b suggest that deprivation of chromatic signals to visual cortex in ACHM may also contribute to changes in cortical morphology. This research shows that the congenital lack of cone input to the visual cortex can lead to widespread structural changes across multiple visual areas.

Triple visual hemifield maps in a case of optic chiasm hypoplasia

In humans, each hemisphere comprises an overlay of two visuotopic maps of the contralateral visual field, one from each eye. Is the capacity of the visual cortex limited to these two maps or are plastic mechanisms available to host more maps? We determined the cortical organization of the visual field maps in a rare individual with chiasma hypoplasia, where visual cortex plasticity is challenged to accommodate three hemifield maps. Using high-resolution fMRI at 7T and diffusion-weighted MRI at 3T, we found three hemiretinal inputs, instead of the normal two, to converge onto the left hemisphere. fMRI-based population receptive field mapping of the left V1-V3 at 3T revealed three superimposed hemifield representations in the left visual cortex, i.e. two representations of opposing visual hemifields from the left eye and one right hemifield representation from the right eye. We conclude that developmental plasticity including the re-wiring of local intra- and cortico-cortical connections is pivotal to support the coexistence and functioning of three hemifield maps within one hemisphere.

Micro-probing enables fine-grained mapping of neuronal populations using fMRI

The characterization of receptive field (RF) properties is fundamental to understanding the neural basis of sensory and cognitive behaviour. The combination of non-invasive imaging, such as fMRI, with biologically inspired neural modelling has enabled the estimation of population RFs directly in humans. However, current approaches require making numerous a priori assumptions, so these cannot reveal unpredicted properties, such as fragmented RFs or subpopulations. This is a critical limitation in studies on adaptation, pathology or reorganization. Here, we introduce micro-probing (MP), a technique for fine-grained and largely assumption free characterization of multiple pRFs within a voxel. It overcomes many limitations of current approaches by enabling detection of unexpected RF shapes, properties and subpopulations, by enhancing the spatial detail with which we analyze the data. MP is based on tiny, fixed-size, Gaussian models that efficiently sample the entire visual space and create fine-grained probe maps. Subsequently, we derived population receptive fields (pRFs) from these maps. We demonstrate the scope of our method through simulations and by mapping the visual fields of healthy participants and of a patient group with highly abnormal RFs due to a congenital pathway disorder. Without using specific stimuli or adapted models, MP mapped the bilateral pRFs characteristic of observers with albinism. In healthy observers, MP revealed that voxels may capture the activity of multiple subpopulations RFs that sample distinct regions of the visual field. Thus, MP provides a versatile framework to visualize, analyze and model, without restrictions, the diverse RFs of cortical subpopulations in health and disease.

Quantifying nerve decussation abnormalities in the optic chiasm

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Diffusion MRI is capable of detecting structural abnormalities of the optic chiasm.

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Quantification of crossing strength in optic chiasm is of promise for albinism diagnostics.

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Optic chiasm is a powerful test model for neuroimaging methods resolving crossing fibers.

Objective

The human optic chiasm comprises partially crossing optic nerve fibers. Here we used diffusion MRI (dMRI) for the in-vivo identification of the abnormally high proportion of crossing fibers found in the optic chiasm of people with albinism.

Methods

In 9 individuals with albinism and 8 controls high-resolution 3T dMRI data was acquired and analyzed with a set of methods for signal modeling [Diffusion Tensor (DT) and Constrained Spherical Deconvolution (CSD)], tractography, and streamline filtering (LiFE, COMMIT, and SIFT2). The number of crossing and non-crossing streamlines and their weights after filtering entered ROC-analyses to compare the discriminative power of the methods based on the area under the curve (AUC). The dMRI results were cross-validated with fMRI estimates of misrouting in a subset of 6 albinotic individuals.

Results

We detected significant group differences in chiasmal crossing for both unfiltered DT (p = 0.014) and CSD tractograms (p = 0.0009) also reflected by AUC measures (for DT and CSD: 0.61 and 0.75, respectively), underlining the discriminative power of the approach. Estimates of crossing strengths obtained with dMRI and fMRI were significantly correlated for CSD (R² = 0.83, p = 0.012). The results show that streamline filtering methods in combination with probabilistic tracking, both optimized for the data at hand, can improve the detection of crossing in the human optic chiasm.

Conclusions

Especially CSD-based tractography provides an efficient approach to detect structural abnormalities in the optic chiasm. The most realistic results were obtained with filtering methods with parameters optimized for the data at hand.

Significance

Our findings demonstrate a novel anatomy-driven approach for the individualized diagnostics of optic chiasm abnormalities.

Population receptive field and connectivity properties of the early visual cortex in human albinism

In albinism, the pathological decussation of the temporal retinal afferents at the optic chiasm leads to superimposed representations of opposing hemifields in the visual cortex. Here, we assessed the equivalence of the two representations and the cortico-cortical connectivity of the early visual areas. Applying fMRI-based population receptive field (pRF)-mapping (both hemifield and bilateral mapping) and connective field (CF)-modeling, we investigated the early visual cortex in 6 albinotic participants and 4 controls. In albinism, superimposed retinotopic representations of the contra- and ipsilateral visual hemifield were observed on the hemisphere contralateral to the stimulated eye. This was confirmed by the observation of bilateral pRFs during bilateral mapping. Hemifield mapping revealed similar pRF-sizes for both hemifield representations throughout V1 to V3. The typical increase of V1-sampling extent for V3 compared to V2 was not found for the albinotic participants. The similarity of the pRF-sizes for opposing visual hemifield representations highlights the equivalence of the two maps in the early visual cortex. The altered V1-sampling extent in V3 might indicate the adaptation of cortico-cortical connections to visual pathway abnormalities in albinism. These findings thus suggest that conservative developmental mechanisms are complemented by alterations of the extrastriate cortico-cortical connectivity.

Interocular transfer of visual memory - Influence of visual impairment and abnormalities of the optic chiasm

Due to an increased crossing of the optic nerve fibers at the optic chiasm in albinism, the visual cortex receives largely monocular input from the contralateral eye. Here we investigated whether this obstruction of binocular integration at the cortical input stage also impacts on interocular information exchange at the high processing level of visual memory. Interocular transfer (IOT) of visual memory retrieval was tested psychophysically after monocular encoding in 8 albinotic participants and 24 healthy controls. The retrieval performance (hit rate, reaction time, d') was determined when using the same or different eye at encoding. To assess the effect of reduced visual acuity (VA) on recognition, we simulated interocular acuity differences (IOA) in two healthy control groups (each n = 8), i.e., with large (VA: 0.89 vs. 0.12) and small simulated interocular difference (VA: 0.25 vs. 0.12), with the latter matched to that observed in the albinotic participants (VA: 0.20 vs. 0.15). A significant decrease in retrieval performance was observed in controls with simulated strongly reduced VA in one eye (p < 0.0001). For the other conditions and groups, including the albinotic participants, no dependence on VA and no significant difference between using the same or different eye was observed. This indicates interocular transfer and hence interocular information exchange in human albinism. These findings thus provide insights into the scope of plasticity of binocular information processing and inter-hemispherical information flow.

Altered organization of the visual cortex in FHONDA syndrome

A fundamental scheme in the organization of the early visual cortex is the retinotopic representation of the contralateral visual hemifield on each hemisphere. We determined the cortical organization in a novel congenital visual pathway disorder, FHONDA-syndrome, where the axons from the temporal retina abnormally cross to the contralateral hemisphere. Using ultra-high field fMRI at 7 T, the population receptive field (pRF) properties of the primary visual cortex were modeled for two affected individuals and two controls. The cortical activation in FHONDA was confined to the hemisphere contralateral to the stimulated eye. Each cortical location was found to contain a pRF in each visual hemifeld and opposing hemifields were represented as retinotopic cortical overlays of mirror-symmetrical locations across the vertical meridian. Since, the enhanced crossing of the retinal fibers at the optic chiasm observed in FHONDA has been previously assumed to be exclusive to the pigment-deficiency in albinism, our direct evidence of abnormal mapping in FHONDA highlights the independence of pigmentation and development of the visual cortex. These findings thus provide fundamental insights into the developmental mechanisms of the human visual system and underline the general relevance of the interplay of subcortical stability and cortical plasticity.

Heterogenous migraine aura symptoms correlate with visual cortex functional magnetic resonance imaging responses

OBJECTIVE

Migraine aura is sparsely studied due to the highly challenging task of capturing patients during aura. Cortical spreading depression (CSD) is likely the underlying phenomenon of aura. The possible correlation between the multifaceted phenomenology of aura symptoms and the effects of CSD on the brain has not been ascertained.

METHODS

Five migraine patients were studied during various forms of aura symptoms induced by hypoxia, sham hypoxia, or physical exercise with concurrent photostimulation. The blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI) signal response to visual stimulation was measured in retinotopic mapping-defined visual cortex areas V1 to V4.

RESULTS

We found reduced BOLD response in patients reporting scotoma and increased response in patients who only experienced positive symptoms. Furthermore, patients with bilateral visual symptoms had corresponding bihemispherical changes in BOLD response.

INTERPRETATION

These findings suggest that different aura symptoms reflect different types of cerebral dysfunction, which correspond to specific changes in BOLD signal reactivity. Furthermore, we provide evidence of bilateral CSD recorded by fMRI during bilateral aura symptoms. Ann Neurol 2017;82:925-939.

[Potential of fMRI for the Functional Assessment of the Pathological Visual System]

Current developments in functional magnetic resonance imaging (fMRI) of the human visual system have generated a set of powerful approaches that are of great promise for modern ophthalmology. These make it possible to perform an objective spatially resolved test of visual function in patients with strong visual impairment and even to investigate the functional organisation of the visual cortex in the blind. As a consequence, they open a broad field of applications for functional assessment in ophthalmology and provide fundamental insights into the interplay of pathology and plasticity in the human visual system. This is highlighted by current studies investigating patients with acquired or congenital defects of the macula, or with visual pathway abnormalities, extended retinal damage, and complete blindness. Therapeutic approaches targeting the restoration of visual input are expected to benefit from these fMRI applications, either for the estimation of the success rate of a planned retinal therapy or as an objective high-level biomarker for the readout of therapy success.

Psychophysical Evidence for Impaired Magno, Parvo, and Konio-cellular Pathways in Dyslexic Children

Purpose:

Dyslexia is one of the most common learning disabilities affecting millions of people worldwide. Although exact causes of dyslexia are not well-known, a deficit in the magnocellular pathway may play a role. We examined possible deficiency of magnocellular, as compared to parvocellular and koniocellular pathway function by measuring luminance and color perception.

Methods:

Visual stimuli consisted of a series of natural images, divided into layers of luminance, red-green and blue-yellow, which probed magnocellular, parvocellular, and koniocellular pathways, respectively. Thirteen children with dyslexia and 13 sex- and age- matched controls performed three psychophysical tasks. In the first task, subjects were instructed to match the contrast of luminance (magno) and red-green (parvo) images to that of the blue-yellow (konio) images. In the second task, subjects detected the isoluminant point of red-green images to probe parvocellular pathway. In the third task, temporal processing was assessed by measuring reaction time and percentage of correct responses in an identification task using four categories of images, activating all three pathways.

Results:

The dyslexic group had significantly elevated luminance and color contrast thresholds and higher isoluminant point ratio in comparison to the control group. Furthermore, they had significantly less correct responses than the control group for the blue-yellow images.

Conclusion:

We may suggest that dyslexic subjects might suffer from both magnocellular and parvocellular deficits. Moreover, our results show partial impairment of the koniocellular pathway. Thus, dyslexia might be associated with deficits in all three visual pathways.

Comparison of nickel doped Zinc Sulfide and/or palladium nanoparticle loaded on activated carbon as efficient adsorbents for kinetic and equilibrium study of removal of Congo Red dye

In this study, the efficiency of nickel doped Zinc Sulfide nanoparticle loaded on activated carbon (Ni-ZnS-NP-AC) and palladium nanoparticles loaded on activated carbon (Pd-NP-AC) for the removal of Congo Red (CR) from aqueous solution was investigated. These materials were fully identified and characterized in term of structure, surface area and pore volume with different techniques such XRD, FE-SEM and TEM analysis. The dependency of CR removal percentage to variables such as pH, contact time, amount of adsorbents, CR concentration was examined and optimum values were set as: 0.03g Ni-ZnS-NP-AC and 0.04g of Pd-NP-AC at pH of 3 and 2 after mixing for 22 and 26min for Ni-ZnS-NP-AC and Pd-NP-AC, respectively. Subsequently, it was revealed that isotherm data efficiency can be correlated Langmuir with maximum monolayer adsorption capacities of 286 and 126.6mgg(-1) at room temperature for Ni-ZnS-NP-AC and Pd-NP-AC, respectively. Investigation of correlation between time and rate of adsorption reveal that the CR adsorption onto both adsorbents followed pseudo second order and interparticle diffusion simultaneously.

THE IMPACT OF ANESTHETIC TECHNIQUES ON COGNITIVE FUNCTIONS AFTER UROLOGICAL SURGERY

BACKGROUND

Postoperative cognitive dysfunction (POCD) is a well-recognized complication of cardiac and noncardiac surgery. However, contradictory results concerning postoperative mental function have been reported. The aim is to determine the effect of anesthetic techniques (general or spinal) on cognitive functions using more sensitive neuropsychological tests in patients undergoing urological surgery.

MATERIAL AND METHODS

A total of thirty patients were enrolled in the study and assigned to receive either general (n = 15) or spinal (n = 15) anesthesia. A battery of neuropsychological tests including Wisconsin Card Sorting Test, Iowa Gambling Task, Stroop Color-Word Test, N-back Task and Continuous Performance Test was performed preoperatively and three days later.

RESULTS

The two experimental groups were similar at baseline assessment of cognitive function. Although there were no statistically significant differences between general and spinal anesthetic groups with respect to Wisconsin Card Sorting Test and Iowa Gambling Task, a significant intergroup difference between pre-and postoperative N-back scores was detected in the general anesthesia group (p = 0.001 & p = 0.004). In addition, patients within this group had significantly higher error rates on the Stroop Color-Word (p = 0.019) and Continuous Performance Tests (p = 0.045). In contrast, patients receiving spinal anesthesia exhibited little change or marginal improvement on all subscales of the battery.

CONCLUSIONS

Our findings indicate significant decline in specific aspects of mental function among patients who were administered general anesthesia compared with the other technique. It seems that spinal anesthesia contributes to lower disturbance after surgery.

The validity of the Menopause-specific Quality of Life questionnaire in women with type 2 diabetes

OBJECTIVES

To examine the validity and reliability of the Menopause-specific Quality of Life (MENQOL) questionnaire in a sample of women with diabetes in Malaysia, with the secondary aim of determining whether MENQOL domain scores were associated with depression and diabetes.

METHODS

A total of 337 postmenopausal women (241 with diabetes, 96 controls) were evaluated. Construct validity was evaluated using principal components analysis (PCA) and comparing scale items against the mental component score of the Short Form-12 (SF-12 MCS), and against the Center for Epidemiologic Studies Depression Scale 10 (CES-D 10). Consistency assessment was conducted using Cronbach's α.

RESULTS

The internal consistencies for the physical (PHS), psychosocial (PS), sexual (VSS) and vasomotor domains were 0.86, 0.79, 0.79 and 0.70, and 0.90 for the full scale of MENQOL. PCA revealed a four-factorial model. Diabetes and non-diabetes subjects experienced their first period (13.25 vs. 13.10 years, p = 0.680) and achieved menopause around the same age (49.35 vs. 48.87 years, p = 0.426). We found significant variations in the MENQOL's PHS and PS domain scores that could be explained by SF-12 PCS (25%) and SF-12 MCS (20%) sub-scales. The validity of the MENQOL domains was demonstrated through significant associations with the equivalent SF-12 MCS and PCS subscales. The PS domain of the MENQOL also predicted the likelihood of symptoms of depression (1.42, 95% confidence interval 1.01-2.02).

CONCLUSIONS

This study confirms the validity and internal consistency of the MENQOL questionnaire for measuring quality of life in postmenopausal women with diabetes, suggesting that the instrument can be used to screen people for menopausal symptoms.

The psychometric properties of an Iranian translation of the Work Ability Index (WAI) questionnaire

BACKGROUND

This study was carried out to evaluate the psychometric properties of an Iranian translation of the Work Ability Index (WAI) questionnaire.

METHODS

In this methodological study, nurses and healthcare workers aged 40 years and older who worked in educational hospitals in Ahvaz (236 workers) in 2010, completed the questionnaire and 60 of the workers filled out the WAI questionnaire for the second time to ensure test-retest reliability. Forward-backward method was applied to translate the questionnaire from English into Persian. The psychometric properties of the Iranian translation of the WAI were assessed using the fallowing tests: Internal consistency (to test reliability), test-retest analysis, exploratory factor analysis (construct validity), discriminate validity by comparing the mean WAI score in two groups of the employees that had different levels of sick leave, criterion validity by determining the correlation between the Persian version of short form health survey (SF-36) and WAI score.

RESULTS

Cronbach's alpha coefficient was estimated to be 0.79 and it was concluded that the internal consistency was high enough. The intraclass correlation coefficient was recognized to be 0.92. Factor analysis indicated three factors in the structure of the work ability including self-perceived work ability (24.5% of the variance), mental resources (22.23% of the variance), and presence of disease and health related limitation (18.55% of the variance). Statistical tests showed that this questionnaire was capable of discriminating two groups of employees who had different levels of sick leave. Criterion validity analysis showed that this instrument and all dimensions of the Iranian version of SF-36 were correlated significantly. Item correlation corrective for overlap showed the items tests had a good correlation except for one.

CONCLUSION

The finding of the study showed that the Iranian version of the WAI is a reliable and valid measure of work ability and can be used both in research and practical activities.

Effects of Watercress (Nasturtium nasturtium) extract on selected immunological parameters of rainbow trout (Oncorhynchus mykiss)

Watercress (Nasturtium nasturtium) is a medical plant containing diverse chemically-active substances with biological properties. The present study was conducted to investigate the immunomodulatory effects of watercress extract on immunological and hematological parameters of rainbow trout (Oncorhynchus mykiss). Fish were fed for 21 days with diet supplemented with 0.1% and 1% of watercress extract per 1 kg food and with a normal diet as control. Hematological parameters such as red blood cells (RBC) and white blood cells (WBC), hematocrit (Hct), hemoglobin (Hb), RBC index like mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration (MCHC) as well as immunological parameters such as peroxidase, lysozyme and complement activities, total protein, albumin and globulin levels were measured after 21 days of watercress extract treatment. The results indicated that oral administration of 1 % watercress extract in fish may enhance some hematological and immunological parameters including Hb and MCHC, lysozyme and complement activities, total protein and globulin levels, compared to the controls after 21 days of experimental period. In conclusion, on the basis of these results, oral administration of watercress extract may be useful to improve fish's immune system.

First Detection of Nosema ceranae, a Microsporidian Protozoa of European Honeybees (Apis mellifera) In Iran

BACKGROUND

Nosemosis of European honey bee (Apis mellifera) is present in bee colonies worldwide. Until recently, Nosema apis had been regarded as the causative agent of the disease, that causes heavy economic losses in apicultures. Nosema ceranae is an emerging microsporidian parasite of European honeybees, A. mellifera, but its distribution is not well known. Previously, nosemosis in honeybees in Iran was attributed exclusively to N. apis.

METHODS

Six Nosema positive samples (determined from light microscopy of spores) of adult worker bees from one province of Iran (Savadkouh- Mazandaran, northern Iran) were tested to determine Nosema species using previously- developed PCR primers of the 16 S rRNA gene. As it is difficult to distinguish N. ceranae and N. apis morphologically, a PCR assay based on 16 S ribosomal RNA has been used to differentiate N. apis and N. ceranae.

RESULTS

Only N. ceranae was found in all samples, indicating that this species present in Iran apiaries.

CONCLUSION

This is the first report of N. ceranae in colonies of A. mellifera in Iran. It seems that intensive surveys are needed to determine the distribution and prevalence of N. ceranae in different regions of Iran.

Understanding of and attitudes toward epilepsy among the urban Chinese population in Malaysia

INTRODUCTION

People with epilepsy are socially discriminated against on the grounds of widespread negative public attitudes, misunderstandings and defensive behaviour. The primary purpose of this study was to evaluate the public understanding of and attitudes toward epilepsy among the Chinese population in Malaysia.

METHODS

A validated, self-administered questionnaire comprising 23 questions was utilised to evaluate the understanding of and attitudes toward epilepsy among randomly approached respondents from the Chinese population living in the urban areas of Penang, Klang Valley, Kuala Lumpur and Sibu in Malaysia.

RESULTS

Out of 1,000 people approached, 697 (69.7 percent) respondents agreed to participate in the study. When asked whether people with epilepsy are slow learners and have intellectual functioning below normal, 448 (64.3 percent) respondents answered 'no'. This positive answer was mainly provided by female (35.6 percent) as compared to male (28.6 percent) respondents. Moreover, more than half responded positively to the following statements: people with epilepsy should not be isolated from the normal population; epileptics can perform daily activities; epileptics can receive academic education; and epileptics can become useful members of society. In addition, significant associations were discovered between the education level of the respondents and several statements, including whether epileptics are as intelligent as everyone else (p-value is 0.009), whether epilepsy can be treated with drugs (p-value is 0.037) and whether epileptics can be as successful as other people in their chosen career (p-value is 0.009). Positive responses were mainly acquired from those with secondary education and above. A large number of the respondents felt that people with epilepsy should not be employed as lorry drivers, firefighters, doctors and army personnel.

CONCLUSION

The general Chinese population in the urban areas of Malaysia had, at the time of the investigation, a relatively high level of understanding and positive attitudes toward certain aspects of epilepsy, although a minority of the study population demonstrated prejudice and discriminatory behaviours toward people with epilepsy.

Paraclinical evaluation of side-effects of Taxanes on auditory system

Ototoxicity is one of the major causes of hearing loss and balance system disorders. Taxanes are a new group of anti-neoplastic agents used for chemotherapy; examples include Paclitaxel and Docetaxel. In this study, ototoxicity of these drugs has been evaluated in order to provide a means of adjusting the doses to avoid these complications. A prospective analytical study was carried out on 103 known cases of breast and ovarian cancer, during 2004 to 2006 (20 months), in the Otolaryngology, Head and Neck Surgery Department of Ahwaz University of Medical Sciences of Tehran. All patients (mean age 45 +/- 2.3 years) were treated with Taxanes. The first evaluation of hearing (using pure tone audiometery) was performed before starting treatment, the second in the middle of the treatment period and the last at the end of treatment. Results showed that nausea and vomiting were the most common side-effects of the drugs used. No significant side-effects of Taxanes, on the audiovestibular system, were observed. In conclusion, little information concerning the ototoxic effect of Taxanes has been reported in other studies, and, in the present investigation, no significant effect on the auditory system was found.

Population genetic approaches to neurological disease: Parkinson's disease as an example

Parkinson's disease (PD) is a common, progressive, incurable disabling condition. The cause is unknown but over the past few years tremendous progress in our understanding of the genetic bases of this condition has been made. To date, this has almost exclusively come from the study of relatively rare Mendelian forms of the disease and there are no currently, widely accepted common variants known to increase susceptibility. The role that the "Mendelian" genes play in common sporadic forms of PD is unknown. Moreover, most studies in PD can really be described as candidate polymorphism studies rather than true and complete assessments of the genes themselves. We provide a model of how one might tackle some of these issues using Parkinson's disease as an illustration. One of the emerging hypotheses of gene environment interaction in Parkinson's disease is based on drug metabolizing (or xenobiotic) enzymes and their interaction with putative environmental toxins. This motivated us to describe a tagging approach for an extensive but not exhaustive list of 55 drug metabolizing enzyme genes. We use these data to illustrate the power, and some of the limitations of a haplotype tagging approach. We show that haplotype tagging is extremely efficient and works well with only a modest increase in effort through different populations. The tagging approach works much less well if the minor allele frequency is below 5%. However, it will now be possible using these tags to evaluate these genes comprehensively in PD and other neurodegenerative conditions.

Controlled trial of maintenance treatment of intravenous buprenorphine dependence

BACKGROUND

Buprenorphine dependence is a relatively novel addiction.

AIMS

To compare the treatment outcome in three groups over 12-weeks of treatment.

METHODS

Two hundred and four intravenous (i.v.)-buprenorphine-dependent patients were randomised into three groups. Subjects received 50 mg oral methadone tablet, or 5 mg sublingual buprenorphine tablet, or 50 mg oral naltrexone, and a weekly 30-minute clinical counselling session.

RESULTS

The majority (80%) had a history of opium or heroin dependency before they were introduced to i.v. buprenorphine. The main source of buprenorphine for misusers was street sale (91%). The mean duration of buprenorphine dependence was 1.9 years and the mean dose per day was 3.9 ampoules (1 ampoule contains 0.3 mg of buprenorphine in 1 ml). Overall 59% of the patients completed the 12-week study. Retention in the 50 mg methadone group was significantly better than the 5 mg dose buprenorphine group (p=0.001) and the 50 mg dose naltrexone group (p=0.000). Retention in the 5 mg buprenorphine group was significantly better than the 50 mg naltrexone dose group (p=0.000).

CONCLUSIONS

These results support the efficacy and safety of oral methadone and sublingual buprenorphine tablets for injection buprenorphine-dependent patients.

Controlled, randomized trial in maintenance treatment of intravenous buprenorphine dependence with naltrexone, methadone or buprenorphine: a novel study

AIMS

To test the effect of a 50-mg day-1 dose of naltrexone in the maintenance treatment of intravenous-buprenorphine dependence in comparison with a 50-mg day-1 dose of methadone and also a 5-mg day-1 dose of buprenorphine over a 24-week treatment period.

PARTICIPANTS

Two hundred and four intravenous-buprenorphine-dependent patients who met the DSM-IV criteria for opioid dependence were randomized to three equal groups and were treated in a clinic in Iran where they were also offered a weekly 0.5-h counselling session, in 2002.

FINDINGS

The mean age was 31.2 years (range 17-53). The majority [63.2%] was between 20 and 34 years of age. The educational level of most of them [55.4%] was between 6 and 12 years of study. Completion rates by groups were 83.8% for the 50-mg dose methadone group, 58.8% for the 5-mg dose buprenorphine group and 20.6% for the 50-mg dose naltrexone group (P = 0.000). Retention in the 50-mg methadone group was significantly better than in the 5-mg dose buprenorphine group (P = 0.001) and the 50-mg dose naltrexone group (P = 0.000). Retention in the 5-mg buprenorphine group was significantly better than in the 50-mg naltrexone dose group (P = 0.000).

CONCLUSIONS

Evaluation of the Iranian experience on this subject may be useful for other countries.

Synthesis and function of 3-phosphorylated inositol lipids

The 3-phosphorylated inositol lipids fulfill roles as second messengers by interacting with the lipid binding domains of a variety of cellular proteins. Such interactions can affect the subcellular localization and aggregation of target proteins, and through allosteric effects, their activity. Generation of 3-phosphoinositides has been documented to influence diverse cellular pathways and hence alter a spectrum of fundamental cellular activities. This review is focused on the 3-phosphoinositide lipids, the synthesis of which is acutely triggered by extracellular stimuli, the enzymes responsible for their synthesis and metabolism, and their cell biological roles. Much knowledge has recently been gained through structural insights into the lipid kinases, their interaction with inhibitors, and the way their 3-phosphoinositide products interact with protein targets. This field is now moving toward a genetic dissection of 3-phosphoinositide action in a variety of model organisms. Such approaches will reveal the true role of the 3-phosphoinositides at the organismal level in health and disease.

Cellular function of phosphoinositide 3-kinases: implications for development, homeostasis, and cancer

The phosphoinositide 3-kinase (PI3K) family of enzymes is recruited upon growth factor receptor activation and produces 3' phosphoinositide lipids. The lipid products of PI3K act as second messengers by binding to and activating diverse cellular target proteins. These events constitute the start of a complex signaling cascade, which ultimately results in the mediation of cellular activities such as proliferation, differentiation, chemotaxis, survival, trafficking, and glucose homeostasis. Therefore, PI3Ks play a central role in many cellular functions. The factors that determine which cellular function is mediated are complex and may be partly attributed to the diversity that exists at each level of the PI3K signaling cascade, such as the type of stimulus, the isoform of PI3K, or the nature of the second messenger lipids. Numerous studies have helped to elucidate some of the key factors that determine cell fate in the context of PI3K signaling. For example, the past two years has seen the publication of many transgenic and knockout mouse studies where either PI3K or its signaling components are deregulated. These models have helped to build a picture of the role of PI3K in physiology and indeed there have been a number of surprises. This review uses such models as a framework to build a profile of PI3K function within both the cell and the organism and focuses, in particular, on the role of PI3K in cell regulation, immunity, and development. The evidence for the role of deregulated PI3K signaling in diseases such as cancer and diabetes is reviewed.

Infants' growth charts for southern Iran

Currently there are no growth charts based on local norms available for infants in Iran, and their growth is assessed by the National Centre for Health Statistics (NCHS) reference data, which is misleading. Growth charts for a cohort of 317 infants (164 girls and 153 boys) born in Shiraz (Southern Iran) in 1996 and followed for 2 years from birth are presented. All the centiles of length and weight charts are slightly above those of the NCHS charts under the age of 6 months and fall substantially below those over the age of 6 months. However, the spread is similar, so there is no suggestion that the difference is due to the prevalence of gross malnutrition. The difference shows that the use of locally based growth charts are essential for assessing the growth of children in Iran. The representativeness of our data leads us to conclude that the charts presented here are likely to be applied to the urban infant population of Iran.

Human phosphoinositide 3-kinase C2beta, the role of calcium and the C2 domain in enzyme activity

The cDNA for a human Class II phosphoinositide 3-kinase (PI 3-kinase C2beta) with a C2 domain was cloned from a U937 monocyte cDNA library and the enzyme expressed in mammalian and insect cells. Like other Class II PI 3-kinases in vitro, PI 3-kinase C2beta utilizes phosphatidylinositol (PI) and PI 4-monophosphate but not PI 4, 5-biphosphate as substrates in the presence of Mg2+. Remarkably, and unlike other PI 3-kinases, the enzyme can use either Mg-ATP or Ca-ATP to generate PI 3-monophosphate. PI 3-kinase C2beta, like the Class I PI 3-kinases, but unlike PI 3-kinase C2alpha, is sensitive to low nanomolar levels of the inhibitor wortmannin. The enzyme is not regulated by the small GTP-binding protein Ras. The C2 domain of the enzyme bound anionic phospholipids such as PI and phosphatidylserine in vitro, but did not co-operatively bind Ca2+ and phospholipids. Deletion of the C2 domain increased the lipid kinase activity suggesting that it functions as a negative regulator of the catalytic domain. Although presently it is not known whether PI 3-kinase C2beta is regulated by Ca2+ in vivo, our results suggest a novel role for Ca2+ ions in phosphate transfer reactions.