Quantifier processing can be dissociated from numerical processing: evidence from semantic dementia patients

Quantifiers such as frequency adverbs (e.g., "always", "never") and quantity pronouns (e.g., "many", "none") convey quantity information. Whether quantifiers are processed as numbers or as general semantics has been a matter of much debate. Some neuropsychological and fMRI studies have found that the processing of quantifiers depends on the numerical magnitude comprehension system, but others have found that quantifier processing is associated with semantic representation. The selective impairment of language in semantic dementia patients provides a way to examine the above controversy. We administered a series of neuropsychological tests (i.e., language processing, numerical processing and semantic distance judgment) to two patients with different levels of severity in semantic dementia (mild vs. severe). The results showed that the two patients had intact numerical knowledge, but impairments in semantic processing. Moreover, the patient with severe/late semantic dementia showed more impairment in quantifier and semantic processing than the patient with mild/early semantic dementia. We concluded that quantifier processing is associated with general semantic processing, not with numerical processing.

Stage-specific gender differences in cognitive and neuropsychiatric manifestations of vascular dementia

Studies on gender differences in the clinical manifestations of vascular dementia (VaD) are still lacking. In the present study, gender comparisons of cognitive and neuropsychiatric profiles were conducted separately for mild and moderate-to-severe VaD in a total of 467 patients with VaD. There were no significant gender differences in cognitive manifestations, except that females performed better on immediate verbal recall than males in mild stage. Women were more likely to exhibit delusions (15.5% vs 7.4%), hallucinations (9.5% vs 3.4%), and depression (43.1% vs 27.3%) in mild stage. The predominance of male patients was observed in apathy at moderate-to-severe stage (50.5% vs 34.8%). To conclude, gender differences existed in neuropsychiatric symptoms of VaD and were especially pronounced in mild stage. Delusions, hallucinations, and depression were more prevalent in females in mild VaD, with the male predominance only in apathy in the later stage.

Montreal cognitive assessment in detecting cognitive impairment in Chinese elderly individuals: a population-based study

The Montreal Cognitive Assessment (MoCA) has been proved brief and sensitive to screen for mild cognitive impairment (MCI) and early dementia in some developed countries or areas. However, little MoCA data are available from mainland China. In this study, the MoCA was applied to 8411 Chinese community dwellers aged 65 or older (6283 = cognitively normal [CN], 1687 = MCI, and 441 = dementia). The MoCA norms were established considering significant influential factors. The optimal cutoff points were 13/14 for illiterate individuals, 19/20 for individuals with 1 to 6 years of education, and 24/25 for individuals with 7 or more years of education. With the optimal cutoffs, the sensitivity of the MoCA was 83.8% for all cognitive impairments, 80.5% for MCI and 96.9% for dementia, and the specificity for identifying CN was 82.5%. These indicate that with optimal cutoffs, the MoCA is valid to screen for cognitive impairment in elderly Chinese living in communities.

The -980C/G polymorphism in APH-1A promoter confers risk of Alzheimer's disease

We previously described an association between Alzheimer's disease (AD) and a single-nucleotide polymorphism -980C/G (rs3754048) in the promoter of the anterior pharynx-defective-1a (APH-1A) gene. Here, we examine the potential of this -980C/G polymorphism to affect APH-1A transcription and confer a risk of AD. We validated the presence of APH-1A promoter polymorphism -980C/G in other two Chinese cohort sets (450 AD and 450 controls). Subsequently, we measured APH-1A mRNA and protein levels and γ-secretase activity in C or G allele carriers. Finally, we examined the polymorphism's transcriptional function using a dual-luciferase reporter assay and also tracked transcription factor binding to the variant promoter sequence with electrophoretic mobility shift assays (EMSAs). We found that the APH-1A levels and γ-secretase activity were higher in individuals carrying allele G. The G allele increased APH-1A transcriptional activity significantly in both N2A cells and HEK293 cells. The EMSA revealed an increased binding of the transcription factor Yin Yang 1 (YY1) to allele G. Overexpression of YY1 resulted in an activation of the APH-1A promoter (2.7-fold). Specific YY1 siRNA led to decreases in APH-1A promoter activity and mRNA and protein levels. Our data indicate that the APH-1A promoter polymorphism -980C/G might alter the binding ability of YY1 transcription factor, resulting in an increased level of APH-1A and γ-secretase activity. These factors further facilitated β-amyloid (Aβ) 42 generation and ultimately modified patients' susceptibility to AD. The involvement of transcription factor YY1 might be a novel mechanism for the development of AD.

Molecular genotyping of Mycobacterium tuberculosis in Xi'an, China, using MIRU-VNTR typing

SETTING

The molecular genotyping of Mycobacterium tuberculosis is expected to lead to a better understanding of M. tuberculosis transmission in Xi'an, one of the largest cities in Western China.

OBJECTIVE

To characterize the population of M. tuberculosis strains circulating in Xi'an and to evaluate the feasibility of the mycobacterial interspersed repetitive units-variable number of tandem repeats (MIRU-VNTR) typing method.

DESIGN

A total of 195 M. tuberculosis clinical isolates from Xi'an were genotyped using spoligotyping and MIRU-VNTR.

RESULTS

Thirty-two different genotypes were identified by spoligotyping, with the Beijing family identified as the largest lineage (84.6%), followed by the T1 (3.08%), T2 (1.54%), H3 (1.03%) and U (1.03%) families. The Hunter-Gaston discriminatory index (HGDI) of spoligotyping is low (HGDI = 0.392). In contrast, 15-locus MIRU-VNTR shows a higher discriminatory power (HGDI = 0.998) than 12-locus MIRU-VNTR (HGDI = 0.948). By replacing the ETR C locus with the MIRU39 locus, the discriminatory power of 15-locus MIRU-VNTR is increased to 0.999.

CONCLUSIONS

The Beijing family accounts for the vast majority of M. tuberculosis isolates in Xi'an, China. The modified 15-locus MIRU-VNTR showed high HGDI and can be used as a first-line genotyping method in combination with spoligotyping in routine epidemiological investigations in Xi'an, China.

Exploration of 16 candidate genes identifies the association of IDE with Alzheimer's disease in Han Chinese

Alzheimer's disease (AD) has a complex pattern of inheritance and many genes have recently been reported to contribute to the disease susceptibility. We selected 106 SNPs within 16 candidate genes and performed a multistage association study using 4 sample sets consisting of 731 AD patients and 738 control subjects to identify genetic factors for AD in Han Chinese. A single nucleotide polymorphism (SNP) in the insulin degrading enzyme gene (IDE), rs3781239, showed a significant association with AD. The C allele increased the risk of AD 1.72-fold than the G allele (odds ratio [OR] = 1.72, 95% confidence interval [CI] = 1.17-2.53, p = 0.006) and CC carriers had a 4.89-fold higher risk for AD than that of the carriers with CG and GG genotypes (odds ratio = 4.89, 95% CI = 1.85-12.91, p = 0.001). Moreover, the CC genotype was significantly associated with earlier age at onset (p = 0.001, hazard ratio [HR] = 2.09, 95% CI = 1.38-3.18). Our data suggest that the polymorphism of IDE is associated with susceptibility to Alzheimer's disease in Han Chinese.

Effects of environmental parameters and irrigation on the turgor pressure of banana plants measured using the non-invasive, online monitoring leaf patch clamp pressure probe

Turgor pressure provides a sensitive indicator for irrigation scheduling. Leaf turgor pressure of Musa acuminate was measured by using the so-called leaf patch clamp pressure probe, i.e. by application of an external, magnetically generated and constantly retained clamp pressure to a leaf patch and determination of the attenuated output pressure P(p) that is highly correlated with the turgor pressure. Real-time recording of P(p) values was made using wireless telemetric transmitters, which send the data to a receiver base station where data are logged and transferred to a GPRS modem linked to an Internet server. Probes functioned over several months under field and laboratory conditions without damage to the leaf patch. Measurements showed that the magnetic-based probe could monitor very sensitively changes in turgor pressure induced by changes in microclimate (temperature, relative humidity, irradiation and wind) and irrigation. Irrigation effects could clearly be distinguished from environmental effects. Interestingly, oscillations in stomatal aperture, which occurred frequently below turgor pressures of 100 kPa towards noon at high transpiration or at high wind speed, were reflected in the P(p) values. The period of pressure oscillations was comparable with the period of oscillations in transpiration and photosynthesis. Multiple probe readings on individual leaves and/or on several leaves over the entire height of the plants further emphasised the great impact of this non-invasive turgor pressure sensor system for elucidating the dynamics of short- and long-distance water transport in higher plants.

Organization of NMDA receptors at extrasynaptic locations

NMDA receptors are found in neurons both at synapses and in extrasynaptic locations. Extrasynaptic locations are poorly characterized. Here we used preembedding immunoperoxidase and postembedding immunogold electron microscopy and fluorescence light microscopy to characterize extrasynaptic NMDA receptor locations in dissociated hippocampal neurons in vitro and in the adult and postnatal hippocampus in vivo. We found that extrasynaptic NMDA receptors on neurons in vivo and in vitro were usually concentrated at points of contact with adjacent processes, which were mainly axons, axon terminals, or glia. Many of these contacts were shown to contain adhesion factors such as cadherin and catenin. We also found associations of extrasynaptic NMDA receptors with the membrane associated guanylate kinase (MAGUKs), postsynaptic density (PSD)-95 and SAP102. Developmental differences were also observed. At postnatal day 2 in vivo, extrasynaptic NMDA receptors could often be found at sites with distinct densities whereas dense material was seen only rarely at sites of extrasynaptic NMDA receptors in the adult hippocampus in vivo. This difference probably indicates that many sites of extrasynaptic NMDA receptors in early postnatal ages represent synapse formation or possibly sites for synapse elimination. At all ages, as suggested in both in vivo and in vitro studies, extrasynaptic NMDA receptors on dendrites or the sides of spines may form complexes with other proteins, in many cases, at stable associations with adjacent cell processes. These associations may facilitate unique functions for extrasynaptic NMDA receptors.

A screen for cognitive assessments for patients with vascular cognitive impairment no dementia

OBJECTIVE

To screen for cognitive assessment for patients with vascular cognitive impairment (VCI) no dementia (V-CIND) from a set of cognitive measures.

METHODS

Extensive neuropsychological tests covering five cognitive domains were performed on 80 V-CIND patients and 80 normal controls. The impaired domains in V-CIND were determined and the most discriminating tests were selected to form a comprehensive assessment. The discriminating validity of the individual tests and the comprehensive assessment were explored.

RESULTS

Compared with the control group, five cognitive domains were all impaired in V-CIND group. World Health Organization-University of California-Los Angeles Auditory Verbal Learning Test (WHO-UCLA AVLT) immediate recall, Semantic Category Verbal Fluency Test (animal), Chinese version of the Wechsler Adult Intelligence Test (WAIS-RC) Digit Symbol Subtest, and Block Design Subtest were finally selected to form a comprehensive assessment tool, which achieved a sensitivity of 92.5% and a specificity of 98.8% in differentiating V-CIND patients from normal controls. Even in the subjects with Mini-Mental State Examination (MMSE) scores of 28 or above, high discriminative validity was also obtained.

CONCLUSIONS

Our study revealed a multiple domain cognitive deficit in V-CIND patients. The comprehensive assessment tapping memory, executive functions, mental processing speed, and visuoconstructive skill may be potentially useful for an overall cognitive evaluation for V-CIND.

Protective immunity induced by daily bites from irradiated mosquitoes infected with Plasmodium yoelii

Individuals in malaria endemic regions do not develop fully protective immune responses against Plasmodium liver stage infections. In high transmission areas, individuals can be exposed to more than two infective mosquito bites daily. Their exposure to Plasmodium sporozoites, therefore, is in the form of small and frequent doses. This is very different from individuals studied in controlled immunization trials where the delivery of large numbers of radiation-attenuated sporozoites in a limited number of doses can induce sterile protective immunity. Using irradiated mosquitoes infected with Plasmodium yoelii 17XNL, we tested whether daily bites from a few mosquitoes can induce a protective immune response in mice. This immunization strategy successfully induced a protective response, preventing the development of liver stages when mice were challenged with nonirradiated sporozoites. These results provide further support for the development of liver stage vaccines. They are also a call for further study into why fully protective responses against the liver stage are not seen in individuals from endemic regions.

The value of the clock drawing test and the mini-mental state examination for identifying vascular cognitive impairment no dementia

OBJECTIVE

To determine the validity of the Clock Drawing Test (CDT) and the Mini-Mental State Examination (MMSE) respectively or in combination for differentiating Vascular Cognitive Impairment No Dementia (V-CIND) from normal subjects.

METHODS

Eighty V-CIND patients and 80 healthy control subjects were blindly evaluated with MMSE, CDT, and additional neuropsychological tests. CDT was scored according to the Rouleau method and AD Cooperative Study method. Sensitivities and specificities of the two CDT measures and MMSE for identifying V-CIND patients were determined. The Areas Under the Receiver Operating Characteristic Curve (AUCs) were compared, and the sensitivity of the combination of CDT with MMSE calculated.

RESULTS

V-CIND group performed worse than controls on both MMSE (p < 0.0001) and the two CDTs (p < 0.0001). In differentiating V-CIND patients from normal subjects, the two CDT measures provided sensitivities of 68.7% and 65.0%, and specificities of 78.7% and 86.2% respectively at optimal cutoff scores, which did no better than MMSE (sensitivity 80%, specificity 70%) (comparison of the AUCs, p = 0.992 and 0.428). The sensitivity of MMSE was marginally higher than that of CDT scored with AD Cooperative Study method (p = 0.053). By combining the two CDT measures with MMSE, the sensitivity was improved to 93.7% and 92.5% respectively.

CONCLUSIONS

Compared with MMSE, CDT is of only similar or even weaker ability for identifying V-CIND. MMSE at a cutoff of 28 may be of some value in detecting V-CIND patients. CDT and MMSE in combination provide a valid instrument for V-CIND screening.

Effects on capacitance by overexpression of membrane proteins

Functional Channelrhodopsin-2 (ChR2) overexpression of about 10(4)channels/mum(2) in the plasma membrane of HEK293 cells was studied by patch-clamp and freeze-fracture electron microscopy. Simultaneous electrorotation measurements revealed that ChR2 expression was accompanied by a marked increase of the area-specific membrane capacitance (C(m)). The C(m) increase apparently resulted partly from an enlargement of the size and/or number of microvilli. This is suggested by a relatively large C(m) of 1.15+/-0.08 microF/cm(2) in ChR2-expressing cells measured under isotonic conditions. This value was much higher than that of the control HEK293 cells (0.79+/-0.02 microF/cm(2)). However, even after complete loss of microvilli under strong hypoosmolar conditions (100 mOsm), the ChR2-expressing cells still exhibited a significantly larger C(m) (0.85+/-0.07 microF/cm(2)) as compared to non-expressing control cells (0.70+/-0.03 microF/cm(2)). Therefore, a second mechanism of capacitance increase may involve changes in the membrane permittivity and/or thickness due to the embedded ChR2 proteins.

A combined patch-clamp and electrorotation study of the voltage- and frequency-dependent membrane capacitance caused by structurally dissimilar lipophilic anions

Interactions of structurally dissimilar anionic compounds with the plasma membrane of HEK293 cells were analyzed by patch clamp and electrorotation. The combined approach provides complementary information on the lipophilicity, preferential affinity of the anions to the inner/outer membrane leaflet, adsorption depth and transmembrane mobility. The anionic species studied here included the well-known lipophilic anions dipicrylamine (DPA⁻), tetraphenylborate (TPB⁻) and [W₂(CO)₁₀(S₂CH)]⁻, the putative lipophilic anion \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {\text{B}}{\left( {{\text{CF}}_{3} } \right)}^{ - }_{4} $$\end{document} and three new heterocyclic W(CO)₅ derivatives. All tested anions partitioned strongly into the cell membrane, as indicated by the capacitance increase in patch-clamped cells. The capacitance increment exhibited a bell-shaped dependence on membrane voltage. The midpoint potentials of the maximum capacitance increment were negative, indicating the exclusion of lipophilic anions from the outer membrane leaflet. The adsorption depth of the large organic anions DPA⁻, TPB⁻ and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {\text{B}}{\left( {{\text{CF}}_{3} } \right)}^{ - }_{4} $$\end{document} increased and that of W(CO)₅ derivatives decreased with increasing concentration of mobile charges. In agreement with the patch-clamp data, electrorotation of cells treated with DPA⁻ and W(CO)₅ derivatives revealed a large dispersion of membrane capacitance in the kilohertz to megahertz range due to the translocation of mobile charges. In contrast, in the presence of TPB⁻ and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {\text{B}}{\left( {{\text{CF}}_{3} } \right)}^{ - }_{4} $$\end{document} no mobile charges could be detected by electrorotation, despite their strong membrane adsorption. Our data suggest that the presence of oxygen atoms in the outer molecular shell is an important factor for the fast translocation ability of lipophilic anions.