Transport and localization of exogenous myelin basic protein mRNA microinjected into oligodendrocytes

We have studied transport and localization of MBP mRNA in oligodendrocytes in culture by microinjecting labeled mRNA into living cells and analyzing the intracellular distribution of the injected RNA by confocal microscopy. Injected mRNA initially appears dispersed in the perikaryon. Within minutes, the RNA forms granules which, in the case of MBP mRNA, are transported down the processes to the periphery of the cell where the distribution again becomes dispersed. In situ hybridization shows that endogenous MBP mRNA in oligodendrocytes also appears as granules in the perikaryon and processes and dispersed in the peripheral membranes. The granules are not released by extraction with non-ionic detergent, indicating that they are associated with the cytoskeletal matrix. Three dimensional visualization indicates that MBP mRNA granules are often aligned in tracks along microtubules traversing the cytoplasm and processes. Several distinct patterns of granule movement are observed. Granules in the processes undergo sustained directional movement with a velocity of approximately 0.2 micron/s. Granules at branch points undergo oscillatory motion with a mean displacement of 0.1 micron/s. Granules in the periphery of the cell circulate randomly with a mean displacement of approximately 1 micron/s. The results are discussed in terms of a multi-step pathway for transport and localization of MBP mRNA in oligodendrocytes. This work represents the first characterization of intracellular movement of mRNA in living cells, and the first description of the role of RNA granules in transport and localization of mRNA in cells.

Transport and localization elements in myelin basic protein mRNA

Myelin basic protein (MBP) mRNA is localized to myelin produced by oligodendrocytes of the central nervous system. MBP mRNA microinjected into oligodendrocytes in primary culture is assembled into granules in the perikaryon, transported along the processes, and localized to the myelin compartment. In this work, microinjection of various deleted and chimeric RNAs was used to delineate regions in MBP mRNA that are required for transport and localization in oligodendrocytes. The results indicate that transport requires a 21-nucleotide sequence, termed the RNA transport signal (RTS), in the 3' UTR of MBP mRNA. Homologous sequences are present in several other localized mRNAs, suggesting that the RTS represents a general transport signal in a variety of different cell types. Insertion of the RTS from MBP mRNA into nontransported mRNAs, causes the RNA to be transported to the oligodendrocyte processes. Localization of mRNA to the myelin compartment requires an additional element, termed the RNA localization region (RLR), contained between nucleotide 1,130 and 1, 473 in the 3' UTR of MBP mRNA. Computer analysis predicts that this region contains a stable secondary structure. If the coding region of the mRNA is deleted, the RLR is no longer required for localization, and the region between nucleotide 667 and 953, containing the RTS, is sufficient for both RNA transport and localization. Thus, localization of coding RNA is RLR dependent, and localization of noncoding RNA is RLR independent, suggesting that they are localized by different pathways.

HypervirulentM. tuberculosisW/Beijing Strains Upregulate Type I IFNs and Increase Expression of Negative Regulators of the Jak-Stat Pathway

The role of type I interferons (IFNs) in the host response to bacterial infections is controversial. Here, we examined the role of IFN-alpha/beta in the murine response to infection with Mycobacterium tuberculosis, using wildtype mice, mice with impaired signaling through the type I IFN receptor (IFNAR), and mice treated to reduce levels of type I IFNs. In this study, we used virulent clinical isolates of M. tuberculosis, including HN878, W4, and CDC1551. Our results indicate that higher levels of type I IFNs are induced by the HN878 and W4 strains. Induction of type I IFNs was associated with lower levels of tumor necrosis factor-alpha (TNF-alpha) and interleukin- 12 (IL-12) and reduced T cell activation, and associated with decreased survival of the mice infected with HN878 or W4 relative to infection with CDC1551. Infection of mice with HN878 and W4 was also associated with relatively higher levels of mRNA for a number of negative regulators of the Jak-Stat signaling pathway, such as suppressors of cytokine signaling (SOCS) 1, 4, and 5, CD45, protein inhibitor of activated Stat1 (PIAS1), protein tyrosine phosphatase nonreceptor type 1 (Ptpn1), and protein tyrosine phosphatase nonreceptor type substrate 1 (Ptpns1). Taken together, these results suggest that increased type I IFNs may be deleterious for survival of M. tuberculosis-infected mice in association with reduced Th1 immunity.

Maternal pre-pregnancy obesity and child neurodevelopmental outcomes: a meta-analysis

This review examined evidence of the association between maternal pre-pregnancy overweight/obesity status and child neurodevelopmental outcomes. PubMed and PsycINFO databases were systematically searched for empirical studies published before April 2017 using keywords related to prenatal obesity and children's neurodevelopment. Of 1483 identified papers, 41 were included in the systematic review, and 32 articles representing 36 cohorts were included in the meta-analysis. Findings indicated that compared with children of normal weight mothers, children whose mothers were overweight or obese prior to pregnancy were at increased risk for compromised neurodevelopmental outcomes (overweight: OR = 1.17, 95% CI [1.11, 1.24], I²  = 65.51; obese: OR = 1.51; 95% CI [1.35, 1.69], I²  = 79.63). Pre-pregnancy obesity increased the risk of attention deficit-hyperactivity disorder (OR = 1.62; 95% CI [1.23, 2.14], I²  = 70.15), autism spectrum disorder (OR = 1.36; 95% CI [1.08, 1.70], I²  = 60.52), developmental delay (OR = 1.58; 95% CI [1.39, 1.79], I²  = 75.77) and emotional/behavioural problems (OR = 1.42; 95% CI [1.26, 1.59], I²  = 87.74). Given the current obesity prevalence among young adults and women of childbearing age, this association between maternal obesity during pregnancy and atypical child neurodevelopment represents a potentially high public health burden.

Modulation of cellular and viral gene expression by the latency-associated nuclear antigen of Kaposi's sarcoma-associated herpesvirus

Kaposi's sarcoma-associated herpesvirus (KSHV), also called human herpesvirus 8 (HHV-8), is the likely etiological agent of Kaposi's sarcoma and primary effusion lymphoma. Common to these malignancies is that tumor cells are latently infected with KSHV. Viral gene expression is limited to a few genes, one of which is the latency-associated nuclear antigen (LANA), the product of ORF73. Examination of the primary sequence of LANA reveals some structural features reminiscent of transcription factors, leading us to hypothesize that LANA may regulate viral and cellular transcription during latency. In reporter gene-based transient transfection assays, we found that LANA can have either positive or negative effects on gene expression. While expression of a reporter gene from several synthetic promoters was increased in the presence of LANA, expression from the human immunodeficiency virus (HIV) long terminal repeat (LTR)-and from NF-kappaB-dependent reporter genes-was reduced by LANA expression. In addition, the promoter of KSHV ORF73 itself is activated up to 5.5-fold by LANA. This autoregulation may be important in tumorigenesis, because two other genes (v-cyclin and v-FLIP) with likely roles in cell growth and survival are also controlled by this element. To identify cellular genes influenced by LANA, we employed cDNA array-based expression profiling. Six known genes (and nine expressed sequence tags) were found to be upregulated in LANA-expressing cell lines. One of these, Staf-50, is known to inhibit expression from the HIV LTR; most of the other known genes are interferon inducible, although the interferon genes themselves were not induced by LANA. These data demonstrate that LANA expression has effects on cellular and viral gene expression. We suggest that, whether direct or indirect in origin, these effects may play important roles in the pathobiology of KSHV infection.

Grid cells and theta as oscillatory interference: electrophysiological data from freely moving rats

The oscillatory interference model (Burgess et al. (2007) Hippocampus 17:801-812) explains the generation of spatially stable, regular firing patterns by medial entorhinal cortical (mEC) grid cells in terms of the interference between velocity-controlled oscillators (VCOs) with different preferred directions. This model predicts specific relationships between the intrinsic firing frequency and spatial scale of grid cell firing, the EEG theta frequency, and running speed (Burgess,2008). Here, we use spectral analyses of EEG and of spike autocorrelograms to estimate the intrinsic firing frequency of grid cells, and the concurrent theta frequency, in mEC Layer II in freely moving rats. The intrinsic firing frequency of grid cells increased with running speed and decreased with grid scale, according to the quantitative prediction of the model. Similarly, theta frequency increased with running speed, which was also predicted by the model. An alternative Moiré interference model (Blair et al.,2007) predicts a direction-dependent variation in intrinsic firing frequency, which was not found. Our results suggest that interference between VCOs generates the spatial firing patterns of entorhinal grid cells according to the oscillatory interference model. They also provide specific constraints on this model of grid cell firing and have more general implications for viewing neuronal processing in terms of interfering oscillatory processes.

Magnetic resonance imaging in the assessment of rheumatoid arthritis--a comparison with plain film radiographs

Conventional radiography lacks sensitivity in early rheumatoid disease. MRI with its advantages of soft tissue discrimination and multiplanar imaging facility might detect earlier disease. This study compares the MR images and conventional radiographs of 11 rheumatoid patients' wrists and carpi. In all cases, erosions were more extensive and numerous on the MR images compared to plain radiographs. MR is useful in detecting early aggressive disease and in monitoring the response to treatments.

Methylation induced premeiotically in Ascobolus: coextension with DNA repeat lengths and effect on transcript elongation

The effect of duplications of gene fragments on the triggering of DNA methylation induced premeiotically (MIP) was studied in the sexual progeny of strains harboring, in addition to the resident met2 gene, a fragment of this gene inserted at an ectopic position. Cytosine methylation of the resident gene was checked for each of the eight duplications tested. Methylation was always found and it was coextensive with the length of the duplications. Silencing of the resident gene was triggered by duplications of segments corresponding to the region 5' to the open reading frame, to only the open reading frame, or to segments beginning 0.87-1.2 kb downstream from the transcription start. Silencing was accompanied by either the absence of transcripts or the presence of truncated transcripts, which suggests that methylation acts on transcript elongation.

Age of acquisition, word frequency, and the role of phonology in the lexical decision task

In five experiments, we examined the respective roles of word age of acquisition (AoA) and frequency in the lexical decision task. The two variables were manipulated orthogonally (while controlling for concreteness and length) in fully factorial designs. Experiment 1 was a conventional lexical decision task, and Experiments 2-5 involved various attempts to interfere with reliance upon phonology. In Experiment 2, only orthographically illegal nonwords were used; in Experiment 3, pseudohomophone nonwords; in Experiment 4, articulatory suppression by the recitation of a nursery rhyme; and in Experiment 5, articulatory suppression by the repetition of a single word. The same basic pattern of results was observed in all experiments: There were main effects of both AoA and frequency, which interacted in such a way that the AoA effect was larger for low- than for high-frequency words. Although the AoA effect was reduced by manipulations intended to interfere with phonological processing, the manipulations did not eliminate the effect. The results are discussed in terms of current models of reading in which it is proposed that AoA has its primary effect on the retrieval of lexical phonology, which appears to be consulted automatically in the lexical decision task.

Mycobacterium tuberculosis inhibits maturation of human monocyte-derived dendritic cells in vitro

To induce effector immunity, dendritic cells (DCs) must differentiate into fully mature cells. We show that, after human monocyte-derived DCs were infected with virulent Mycobacterium tuberculosis, up-regulation of cellular-surface maturation markers was minimal and reversible. In the presence of a potent stimulus for maturation (tumor necrosis factor [TNF]-alpha, interleukin [IL]-1beta, and prostaglandin E2 [PGE2]), M. tuberculosis inhibited phenotypic DC maturation. M. tuberculosis-infected DCs had an impaired ability to induce allogeneic lymphoproliferation and activated autologous memory CD4+ and CD8+ T cells optimally only in the presence of TNF-alpha, IL-1beta, and PGE2. Thus, virulent M. tuberculosis inhibits phenotypic and functional maturation of human monocyte-derived DCs. This mechanism, which has been described elsewhere for various viruses and for the virulent mycobacterium M. leprae, may be a novel mechanism that this pathogen uses to evade the host's immune response.

Pulsed high frequency (27MHz) electromagnetic therapy for persistent neck pain. A double blind, placebo-controlled study of 20 patients

In the majority of patients with neck pain, symptoms will resolve spontaneously or quite quickly in response to therapy. However, some patients' symptoms persist for a long period, irrespective of therapy. In this study, 20 patients with persistent (greater than 8 weeks) neck pain were enrolled in a double blind, placebo-controlled trial of low energy, pulsed electromagnetic therapy (PEMT)--a treatment previously shown to be effective in soft tissue injuries. For the first 3-week period, group A (10 patients) received active PEMT units while group B (10 patients) received facsimile placebo units. After 3 weeks, both pain (visual analogue scale (P less than .023) and range of movement (P less than .002) had improved in the group on active treatment compared to the controls. After the second 3 weeks, during which both groups used active units, there were significant improvements in observed scores for pain and range of movement in both groups. PEMT, in the form described, can be used at home easily in the treatment of patients with neck pain. It is frequently successful and without side effects.

Reliability of physical performance measures in nursing home residents with Alzheimer's disease

BACKGROUND

Investigation of the effects of exercise on frail, institutionalized individuals with dementia has been impeded by concerns about the reliability of physical performance measures when used in this population.

METHODS

The physical performance of 33 institutionalized subjects with Alzheimer's disease was measured during both the morning and afternoon of day 1 by rater 1 and during both the morning and afternoon of day 2, one week later, by rater 1 and rater 2. Intraclass correlation coefficients (ICCs) were calculated to examine the inter- and intrarater reliability of "sit to stand," "25-foot walk," and "the distance walked in 6 minutes" and walking speed over 25 feet and for 6 minutes. An analysis of variance was performed to determine the components of variance for each test.

RESULTS

ICCs for "distance walked in 6 minutes" ranged from .80 to .99 with 77% of the variance explained by inter-subject difference. The ICCs for "time to walk 25 feet" ranged from .57 to .97 with 25% of the variance explained by inter-subject differences. In contrast, the "sit to stand" measure produced ICCs ranging from -.07 to .85 with only 7% of the variance explained by inter-subject differences in this impaired population.

CONCLUSION

Our results support the contention that some physical performance measures can be used to test individuals in the later stages of Alzheimer's disease given appropriate modification. Although subjects with Alzheimer's disease may have difficulty following commands and/or require physical assistance, this does not prohibit the reliable assessment of physical performance if measurements are made over longer (6-minute walk) rather than shorter periods (25-foot walk).

Neural mechanisms of self-location

The ability to self-localise and to navigate to remembered goals in complex and changeable environments is crucial to the survival of many mobile species. Electrophysiological investigations of the mammalian hippocampus and associated brain structures have identified several classes of neurons which represent information about an organism's position and orientation. These include place cells, grid cells, head direction cells, and boundary vector cells, as well as cells representing aspects of self-motion. Understanding how these neural representations are formed and updated from environmental sensory information and from information relating to self-motion is an important topic attracting considerable current interest. Here we review the computational mechanisms thought to underlie the formation of these different spatial representations, the interactions between them, and their use in guiding behaviour. These include some of the clearest examples of computational mechanisms of general interest to neuroscience, such as attractor dynamics, temporal coding and multi-modal integration. We also discuss the close relationships between computational modelling and experimental research which are driving progress in this area.

Psychiatric disorder among boys with Duchenne muscular dystrophy

The prevalence of psychiatric disorder in 23 boys with Duchenne muscular dystrophy was assessed and compared to a matched control group. Dysthymic disorder and major depressive disorder occurred significantly more often among DMD boys than controls. Older boys with DMD were at greater risk of depressive disorder than younger boys. Possible aetiological factors and approaches to management are discussed.

Neurobehavioral symptoms in childhood closed-head injuries: changes in prevalence and correlates during the first year postinjury

OBJECTIVE

To examine changes in the prevalence and correlates of neurobehavioral symptoms during the first year following childhood closed-head injuries (CHIs).

METHODS

Participants included 31 children with severe CHIs, 38 with moderate CHIs, and 53 with orthopedic injuries (OIs). Children and their families were assessed shortly after injury and at 6- and 12-month follow-ups. Parents rated 15 symptoms classified as either cognitive/somatic (C/S) or emotional/behavioral (E/B).

RESULTS

Both kinds of symptoms were more common in the CHI groups than in the OI group. C/S symptoms declined in the CHI groups over time, whereas E/B symptoms became relatively more common. Measures of injury severity, children's premorbid behavioral adjustment, and concurrent cognitive functioning predicted C/S symptoms. E/B symptoms were predicted by injury severity, concurrent cognitive functioning soon after the injury, and concurrent parent and family functioning later in time. Both types of symptoms contributed to the prediction of perceived family burden, with the relationships strengthening over time.

CONCLUSIONS

The findings indicate that the prevalence and correlates of neurobehavioral symptoms in childhood CHIs vary as a function of symptom type and time since injury.

Rapid detection of Mycobacterium tuberculosis biomarkers in a sandwich immunoassay format using a waveguide-based optical biosensor

Early diagnosis of active tuberculosis (TB) remains an elusive challenge, especially in individuals with disseminated TB and HIV co-infection. Recent studies have shown a promise for the direct detection of pathogen-specific biomarkers such as lipoarabinomannan (LAM) for the diagnosis of TB in HIV-positive individuals. Currently, traditional immunoassay platforms that suffer from poor sensitivity and high non-specific interactions are used for the detection of such biomarkers. In this manuscript, we demonstrate the development of sandwich immunoassays for the direct detection of three TB-specific biomarkers, namely LAM, early secretory antigenic target 6 (ESAT6) and antigen 85 complex (Ag85), using a waveguide-based optical biosensor platform. Combining detection within the evanescent field of a planar optical waveguide with functional surfaces that reduce non-specific interactions allows for the ultra-sensitive and quantitative detection of biomarkers (an order of magnitude enhanced sensitivity, as compared to plate-based ELISA) in complex patient samples (urine, serum) within a short time. We also demonstrate the detection of LAM in urine from a small sample of subjects being treated for TB using this approach with excellent sensitivity and 100% corroboration with disease status. These results suggest that pathogen-specific biomarkers can be applied for the rapid and effective diagnosis of disease. It is likely that detection of a combination of biomarkers offers greater reliability of diagnosis, rather than detection of any single pathogen biomarker. NCT00341601.

Theta phase precession of grid and place cell firing in open environments

Place and grid cells in the rodent hippocampal formation tend to fire spikes at successively earlier phases relative to the local field potential theta rhythm as the animal runs through the cell's firing field on a linear track. However, this ‘phase precession’ effect is less well characterized during foraging in two-dimensional open field environments. Here, we mapped runs through the firing fields onto a unit circle to pool data from multiple runs. We asked which of seven behavioural and physiological variables show the best circular–linear correlation with the theta phase of spikes from place cells in hippocampal area CA1 and from grid cells from superficial layers of medial entorhinal cortex. The best correlate was the distance to the firing field peak projected onto the animal's current running direction. This was significantly stronger than other correlates, such as instantaneous firing rate and time-in-field, but similar in strength to correlates with other measures of distance travelled through the firing field. Phase precession was stronger in place cells than grid cells overall, and robust phase precession was seen in traversals through firing field peripheries (although somewhat less than in traversals through the centre), consistent with phase coding of displacement along the current direction. This type of phase coding, of place field distance ahead of or behind the animal, may be useful for allowing calculation of goal directions during navigation.

Expression and localization of myelin basic protein in oligodendrocytes and transfected fibroblasts

Myelin basic protein (MBP) is a major structural component of myelin. It is expressed exclusively in myelinating glia (oligodendrocytes in the CNS and Schwann cells in the PNS) and is localized to the cytoplasmic surface of the plasma membrane and myelin membrane produced by these cells. The work described here concerns the mechanism of plasma membrane localization of MBP in myelinating glial cells and whether it involves differentiated functions specific to these cells or general functions of plasma membrane assembly common to all cells. To this end, the subcellular localization of endogenous MBP in mouse oligodendrocytes was compared with that of transiently expressed MBP in monkey fibroblasts (Cos-1 cells) transfected with an MBP expression vector containing cDNA for rat 14K MBP. The steady-state levels of MBP-specific RNA and of MBP polypeptide expressed in the transfected fibroblasts were comparable to the levels expressed in oligodendrocytes in primary culture. MBP localization was analyzed in whole cells by immunofluorescence and in specific intracellular compartments by subcellular fractionation. The results show that MBP expressed in wild-type oligodendrocytes is localized to the plasma membrane. In contrast, MBP expressed in transfected fibroblasts appears dispersed in the cytoplasm and is distributed uniformly among the various subcellular fractions.(ABSTRACT TRUNCATED AT 250 WORDS)

Age-of-acquisition and frequency effects in speeded word naming

An experiment was conducted to assess the importance of age-of-acquisition and frequency in a speeded word naming task, where participants were instructed to read aloud words before they disappeared from the computer screen. Under such speeded naming instructions, reading latencies were over 100ms (or 20%) faster than in "standard" (or immediate) word naming. There were clear effects of word frequency and age-of-acquisition under speeded naming. Compared to standard immediate naming, the age-of-acquisition effect was larger, with early-acquired words being speeded up more than late-acquired words, which is interpreted in terms of speeded naming reducing the contribution of sublexical processing to word naming times.

Non-mydriatic fundus photography: a viable alternative to fundoscopy for identification of diabetic retinopathy in an Aboriginal population in rural Western Australia?

PURPOSE

To evaluate the Canon CR5-45NM non-mydriatic fundus camera (Canon, Kanagawa, Japan) for identifying retinopathy and the need for laser treatment in a population of Aboriginal patients with diabetes mellitus in rural Western Australia.

METHODS

Diabetic Aboriginal patients were photographed through undilated pupils using a Canon CR5-45NM non-mydriatic fundus camera, after which ophthalmoscopy was performed using indirect ophthalmoscopy through dilated pupils. The examining ophthalmologist recorded the presence of retinopathy and the need for laser treatment. A proportion of patients were rephotographed through dilated pupils. Photographs were reviewed by a second ophthalmologist who evaluated the quality of the image, the presence of retinopathy and the need for laser treatment. Results of fundus photographs and ophthalmoscopy were compared.

RESULTS

Three hundred and twenty-eight eyes in 164 Aboriginal patients were examined. The mean patient age was 48.2 years (range 16-81 years) and the mean duration of diabetes was 7.5 years (range 1-35 years). Seventy-four eyes (22.6%) were diagnosed with retinopathy using combined examination techniques, 44 (59.5%) of which were identified by ophthalmoscopy and 55 (74.3%) by photography. Thirty-five eyes were deemed to need treatment, 18 (51.4%) of which were identified by ophthalmoscopy and 30 (85.7%) by photography. Kappa coefficient measurement for agreement for presence of retinopathy and need for referral was 0.41 and 0.53, respectively. Photograph quality was significantly improved following pupil dilation.

CONCLUSIONS

The Canon CR5-45NM non-mydriatic fundus camera was relatively good at identifying diabetic retinopathy and could usefully be applied within a screening programme for treatable disease within this population.

Familiarity decisions for faces presented to the left and right cerebral hemispheres

Right-handed subjects were asked to decide whether or not faces presented briefly in the RVF or in the LVF were familiar (familiar faces were those of famous people). This task avoids the need for extensive semantic processing or temporary storage involved in conventional naming or identification tasks, and thus eliminates the contribution of such factors to any observed asymmetry. The resulting finding of faster reaction times to LVF faces, with no overall visual hemifield difference in error rates, is taken to indicate a right-hemisphere superiority either in the processes used to construct facial representations or in the accessing of face recognition units, or both.

Anticardiolipin antibodies in rheumatoid arthritis

Anticardiolipin antibody (ACA) was present in the sera of 49% of 90 consecutive patients with rheumatoid arthritis (RA). The ACA was absent in 30 control patients with osteoarthritis. C-reactive protein levels equal to or exceeding 7 mg/dl were found in 10 patients all of whom were ACA positive. ACA was present in a larger proportion of rheumatoid factor (RF) positive than of RF negative patients. Male sex and extra-articular manifestations of RA were both more common in ACA positive than ACA negative patients. In the ACA positive group the lupus anticoagulant and VDRL tests were negative. However, a small number of patients had evidence of vascular events.