Search

The rapid development of high-throughput techniques and expansion of bacterial databases have accelerated efforts to bring plant microbiomes into cultivation. We introduced plant-only-based culture media as a successful candidate to mimic the nutritional matrices of plant roots. We herein employed a G3 PhyloChip microarray to meticulously characterize the culture-dependent and -independent bacterial communities of the maize root compartments, the endo- and ecto-rhizospheres. An emphasis was placed on the preference of the growth of unculturable candidate divisions/phyla on plant-only-based culture media over standard culture media (nutrient agar). A total of 1,818 different operational taxonomic units (OTUs) were resolved representing 67 bacterial phyla. Plant-only-based culture media displayed particular affinity towards recovering endophytic over ectophytic rhizobacteria. This was shown by the slightly higher recovery of CFUs for endophytes on plant-only-based culture media (26%) than on standard culture media (10%) as well as the higher taxa richness and numbers of exclusive families of unculturable divisions/phyla. Out of 30 bacterial phyla (comprising >95% of the whole population), 13 were of a significantly higher incidence on plant-only-based culture media, 6 phyla of which were not-yet-cultured (Atribacteria, OP9; Dependentiae, TM6; Latescibacteria, WS3; Marinimicrobia, SAR406; Omnitrophica, OP3; BRC1). Furthermore, plant-only-based culture media significantly enriched less abundant and/or hard-to-culture bacterial phyla (Acidobacteria, Gemmatimonadetes, and Tenericutes). These results present conclusive evidence of the ability of plant-only-based culture media to bring the plant-fed in situ microbiome into the status of plant-fed in vitro cultures, and to widen the scope of cultivation of heretofore-unculturable bacterial divisions/phyla.

Exploiting native plant growth-promoting rhizobacteria (PGPR) in Cameroonian agro-ecosystems provides a means to improve plant-microbe interactions that may enhance ecosystem sustainability and agricultural productivity in an environmentally eco-friendly way. Consequently, we aimed to investigate the community structure and functional PGPR diversity of maize grown in Cameroon. Native bacteria isolated from Cameroon maize rhizosphere soil were identified by partial 16S rRNA gene sequencing and screened for traits particularly relevant for Cameroon low-fertility soil conditions, such as their abilities to tolerate high concentrations of salt, and their plant growth- promoting potential. Genetic and functional diversity was characterized according to their phylogenetic affiliation. A total of 143 bacteria were identified and assigned to 3 phyla (Actinobacteria, Firmicutes and Proteobacteria), 13 families and 20 genera. Bacillus (31.5%), Arthrobacter (17.5%), and Sinomonas (13.3%) were the most abundant genera identified among all the isolates. Based on their in vitro characterization, 88.1% were salt tolerant at 2% NaCl, but only 16.8% could tolerate 8% NaCl, 50.4% solubilized phosphate, 10.5% possessed the nifH gene, and 19.6% produced siderophores. Six isolates affiliated to the most abundant genera identified in this work, Bacillus and Arthrobacter, carrying multiple or only single tested traits were selected to evaluate their growth- promoting potential in an in vitro maize germination assay. Three strains possessing multiple traits induced significantly increased hypocotyl and root length of maize seeds compared to non-inoculated control seeds. Our results indicate the potential of selected indigenous Cameroon rhizobacteria to enhance maize growth., (Copyright © 2018 The Authors. Published by Elsevier GmbH.. All rights reserved.)

The recent worldwide discovery of plant growth-promoting (PGP) Kosakonia radicincitans in a large variety of crop plants suggests that this species confers significant influence on plants, both in terms of yield increase and product quality improvement. We provide a comparative genome analysis which helps to unravel the genetic basis for K. radicincitans' motility, competitiveness and plant growth-promoting capacities. We discovered that K. radicincitans carries multiple copies of complex gene clusters, among them two flagellar systems and three type VI secretion systems (T6SSs). We speculate that host invasion may be facilitated by different flagella, and bacterial competitor suppression by effector proteins ejected via T6SSs. We found a large plasmid in K. radicincitans DSM 16656 T , the species type strain, that confers the potential to exploit plant-derived carbon sources. We propose that multiple copies of complex gene clusters in K. radicincitans are metabolically expensive but provide competitive advantage over other bacterial strains in nutrient-rich environments. The comparison of the DSM 16656 T genome to genomes of other genera of enteric plant growth-promoting bacteria (PGPB) exhibits traits unique to DSM 16656 T and K. radicincitans , respectively, and traits shared between genera. We used the output of the in silico analysis for predicting the purpose of genomic features unique to K. radicincitans and performed microarray, PhyloChip, and microscopical analyses to gain deeper insight into the interaction of DSM 16656 T , plants and associated microbiota. The comparative genome analysis will facilitate the future search for promising candidates of PGPB for sustainable crop production.

Background and Purpose: Currently no quantitative objective test exists to determine disease severity in a patient with Chiari I malformation. Our aim was to correlate disease severity in symptomatic patients with Chiari I malformation with cough-associated changes in CSF flow as measured with real-time MR imaging., Materials and Methods: Thirteen symptomatic patients with Chiari I malformation (tonsillar herniation of ≥5 mm) were prospectively studied. A real-time, flow-sensitized pencil-beam MR imaging scan was used to measure CSF stroke volume during rest and immediately following coughing and relaxation periods (total scan time, 90 seconds). Multiple posterior fossa and craniocervical anatomic measurements were also obtained. Patients were classified into 2 groups by neurosurgeons blinded to MR imaging measurements: 1) nonspecific Chiari I malformation (5/13)-Chiari I malformation with nonspecific symptoms like non-cough-related or mild occasional cough-related headache, neck pain, dizziness, paresthesias, and/or trouble swallowing; 2) specific Chiari I malformation (8/13)-patients with Chiari I malformation with specific symptoms and/or objective findings like severe cough-related headache, myelopathy, syringomyelia, and muscle atrophy. The Spearman correlation was used to determine correlations between MR imaging measurements and disease severity, and both groups were also compared using a Mann-Whitney U test., Results: There was a significant negative correlation between the percentage change in CSF stroke volume (resting to postcoughing) and Chiari I malformation disease severity ( R = 0.59; P = .03). Mann-Whitney comparisons showed the percentage change in CSF stroke volume (resting to postcoughing) to be significantly different between patient groups ( P = .04). No other CSF flow measurement or anatomic measure was significantly different between the groups., Conclusions: Our exploratory study suggests that assessment of CSF flow response to a coughing challenge has the potential to become a valuable objective noninvasive test for clinical assessment of disease severity in patients with Chiari I malformation., (© 2018 by American Journal of Neuroradiology.)

Bacteria, which establish positive interactions with plant roots, play a key role in agricultural environments and are promising for their potential use in sustainable agriculture. Many of these mutualistic bacteria provide benefits to plant hosts by facilitating soil mineral nutrient uptake, protecting plants from biotic and abiotic stresses and producing substances that promote growth. The dataset presented here, is related to the publication entitled "Community structure and plant growth-promoting potential of cultivable bacteria isolated from Cameroon soil" (Tchuisseu et al., 2018) [1]. The data provide an extended analysis of the occurrence, taxonomical affiliation and functional traits of bacterial groups isolated from the rhizosphere of maize in Cameroon at different taxonomical levels, using a combination of molecular/bioinformatics tools and in vitro studies. Bacteria were isolated from maize rhizosphere soil. Isolated bacteria were identified using the 16s rRNA gene sequencing and phylogenetic analyses. All strains were characterized for their potential of salinity tolerance and growth promotion (phosphate solubilization, nifH gene presence and siderophore production) in order to select efficient bacterial strains for designing biological fertilizer exploitable for agriculture under specific stress conditions of the country. The data will be valuable for further studies on plant associated bacteria in Cameroon, which are still largely unexplored.

The global market for biosupplements is expected to grow by 14 percent between 2014 and 2019 as a consequence of the proven benefits of biosupplements on crop yields, soil fertility, and fertilizer efficiency. One important segment of biosupplements is plant growth-promoting bacteria (PGPB). Although many potential PGPB have been discovered, suitable biotechnological processing and shelf-life stability of the bacteria are challenges to overcome for their successful use as biosupplements. Here, the plant growth-promoting Gram-negative strain Kosakonia radicincitans DSM 16656 T (family Enterobacteriaceae) was biotechnologically processed and applied in the field. Solid or liquid formulations of K. radicincitans were diluted in water and sprayed on young maize plants ( Zea mays L.). Shelf-life stability tests of formulated bacteria were performed under 4°C and -20°C storage conditions. In parallel, the bacterial formulations were tested at three different farm level field plots characterized by different soil properties. Maize yield was recorded at harvest time, and both formulations increased maize yields in silage as well as grain maize, underlining their positive impact on different agricultural systems. Our results demonstrate that bacteria of the family Enterobacteriaceae, although incapable of forming spores, can be processed to successful biosupplements.

Biological nitrogen fixation (BNF) is considered one of the key plant-growth-promoting (PGP) factors for diazotrophic organisms. Whether the iron and iron-molybdenum nitrogenases of Kosakonia radicincitans contribute to its PGP effect is yet to be proven. Hence, for the first time, we conducted site-directed mutagenesis in K. radicincitans to knock out anfH and (or) nifH as a mean to deactivate BNF in this strain. We used 15 N 2 -labeled air to trace BNF activities in ΔanfH, ΔnifH, and ΔanfHΔnifH mutants. Assessing bacterial growth, nitrogen content, and 15 N incorporation revealed that BNF is impaired in K. radicincitans DSM16656 T ΔnifH and ΔanfHΔnifH. However, we detected no significant contribution of the Fe nitrogenase to biological dinitrogen assimilation under our pure bacterial culture experimental conditions. Such nondiazotrophic K. radicincitans DSM16656 T mutants represent excellent tools for investigating nitrogen nutrition in K. radicincitans-inoculated plants.

In an effort to axenically culture the previously uncultivable populations of the rhizobacteria of Lucerne (Medicago sativa L.), we propose plant-only teabags culture media to mimic the nutritional matrix available in the rhizosphere. Here, we show that culture media prepared from Lucerne powder teabags substantially increased the cultivability of Lucerne rhizobacteria compared with a standard nutrient agar, where we found that the cultivable populations significantly increased by up to 60% of the total bacterial numbers as estimated by Quantitative Real-time Polymerase Chain Reaction (qRT-PCR). Cluster analysis of 16S rDNA Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis (PCR-DGGE) of cultivable Colony-Forming Units (CFUs) revealed a more distinct composition and separation of bacterial populations recovered on the plant-only teabags culture media than those developed on a standard nutrient agar. Further, the new plant medium gave preference to the micro-symbiont Sinorhizobium meliloti, and succeeded in isolating a number of not-yet-cultured bacteria, most closely matched to Novosphingobium sp., Lysobacter sp. and Pedobacter sp. The present study may encourage other researchers to consider moving from the well-established standard culture media to the challenging new plant-only culture media. Such a move may reveal previously hidden members of rhizobacteria, and help to further explore their potential environmental impacts.

Minipump infusions into visual cortex in vivo at the onset of the critical period have revealed that the proinflammatory cytokine leukemia inhibitory factor (LIF) delays the maturation of thalamocortical projection neurons of the lateral geniculate nucleus, and tecto-thalamic projection neurons of the superior colliculus, and cortical layer IV spiny stellates and layer VI pyramidal neurons. Here, we report that P12-20 LIF infusion inhibits somatic maturation of pyramidal neurons and of all interneuron types in vivo. Likewise, DIV 12-20 LIF treatment in organotypic cultures prevents somatic growth GABA-ergic neurons. Further, while NPY expression is increased in the LIF-infused hemispheres, the expression of parvalbumin mRNA and protein, Kv3.1 mRNA, calbindin D-28k protein, and GAD-65 mRNA, but not of GAD-67 mRNA or calretinin protein is substantially reduced. Also, LIF treatment decreases parvalbumin, Kv3.1, Kv3.2 and GAD-65, but not GAD-67 mRNA expression in OTC. Developing cortical neurons are known to depend on neurotrophins. Indeed, LIF alters neurotrophin mRNA expression, and prevents the growth promoting action of neurotophin-4 in GABA-ergic neurons. The results imply that LIF, by altering neurotrophin expression and/or signaling, could counteract neurotrophin-dependent growth and neurochemical differentiation of cortical neurons., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Nitric oxide (NO) has frequently been associated with secondary damage after brain injury. However, average NO levels in different brain regions before and after traumatic brain injury (TBI) and its role in post-TBI mitochondrial dysfunction remain unclear. In this comprehensive profiling study, we demonstrate for the first time that basal NO levels vary significantly in the healthy cortex (0.44 ± 0.04 μM), hippocampus (0.26 ± 0.03 μM), and cerebellum (1.24 ± 0.08 μM). Within 4 h of severe lateral fluid percussion injury, NO levels almost doubled in these regions, thereby preserving regional differences in NO levels. TBI-induced NO generation was associated with inducible NO synthase (iNOS) increase in ipsilateral but not in contralateral regions. The transient NO increase resulted in a persistent tyrosine nitration adjacent to the injury site. Nitrosative stress-associated cell loss via apoptosis and receptor-interacting serine/threonine-protein kinase 3 (RIPK3)-mediated necrosis were also observed in the ipsilateral cortex, despite high levels of NO in the contralateral cortex. NO-mediated impairment of mitochondrial state 3 respiration dependent on complex I substrates was transient and confined to the ipsilateral cortex. Our results demonstrate that NO dynamics and associated effects differ in various regions of the injured brain. A potential association between the observed mitochondrial electron flow through complex I, but not complex II, and the modulation of TBI induced NO levels in different brain regions has to be prospectively analyzed in more detail.

Background and Purpose: Invasive pressure studies have suggested that CSF flow across the foramen magnum may transiently decrease after coughing in patients with symptomatic Chiari I malformation. The purpose of this exploratory study was to demonstrate this phenomenon noninvasively by assessing CSF flow response to coughing in symptomatic patients with Chiari I malformation by using MR pencil beam imaging and to compare the response with that in healthy participants., Materials and Methods: Eight symptomatic patients with Chiari I malformation and 6 healthy participants were studied by using MR pencil beam imaging with a temporal resolution of ∼50 ms. Patients and healthy participants were scanned for 90 seconds (without cardiac gating) to continuously record cardiac cycle-related CSF flow waveforms in real-time during resting, coughing, and postcoughing periods. CSF flow waveform amplitude, CSF stroke volume, and CSF flow rate (CSF Flow Rate = CSF Stroke Volume × Heart Rate) in the resting and immediate postcoughing periods were determined and compared between patients and healthy participants., Results: There was no significant difference in CSF flow waveform amplitude, CSF stroke volume, and the CSF flow rate between patients with Chiari I malformation and healthy participants during rest. However, immediately after coughing, a significant decrease in CSF flow waveform amplitude (P < .001), CSF stroke volume (P = .001), and CSF flow rate (P = .001) was observed in patients with Chiari I malformation but not in the healthy participants., Conclusions: Real-time MR imaging noninvasively showed a transient decrease in CSF flow across the foramen magnum after coughing in symptomatic patients with Chiari I malformation, a phenomenon not seen in healthy participants. Our results provide preliminary evidence that the physiology-based imaging method used here has the potential to be an objective clinical test to differentiate symptomatic from asymptomatic patients with Chiari I malformation., (© 2016 by American Journal of Neuroradiology.)

Computed tomography is the first-line modality for evaluation of chest diseases primarily because of its spatial resolution. Magnetic resonance (MR) imaging is used as a problem-solving tool to answer key questions that are vital to optimal patient management. MR has the potential to provide qualitative, quantitative, anatomic, and functional information without the use of ionizing radiation or nephrotoxic contrast administration. With new advances in proton MR techniques, MR imaging can overcome some of the inherent problems associated with imaging the lung. This article describes novel MR applications for evaluation of the pleura and pleural diseases., (Copyright © 2015 Elsevier Inc. All rights reserved.)

In this work, we report initial results from a light-weight, low field magnetic resonance device designed to make relative pulmonary density measurements at the bedside. The development of this device necessarily involves special considerations for the magnet, RF and data acquisition schemes as well as a careful analysis of what is needed to provide useful information in the ICU. A homogeneous field region is created remotely from the surface of the magnet such that when the magnet is placed against the chest, an NMR signal is measured from a small volume in the lung. In order to achieve portability, one must trade off field strength and therefore spatial resolution. We report initial measurements from a ping-pong ball size region in the lung as a function of lung volume. As expected, we measured decreased signal at larger lung volumes since lung density decreases with increasing lung volume. Using a CPMG sequence with ΔTE=3.5 ms and a 20 echo train, a signal to noise ratio ~1100 was obtained from an 8.8mT planar magnet after signal averaging for 43 s. This is the first demonstration of NMR measurements made on a human lung with a light-weight planar NMR device. We argue that very low spatial resolution measurements of different lobar lung regions will provide useful diagnostic information for clinicians treating Acute Respiratory Distress Syndrome as clinicians want to avoid ventilator pressures that cause either lung over distension (too much pressure) or lung collapse (too little pressure)., (Copyright © 2014 John Wiley & Sons, Ltd.)

Here we provide a full report on the construction, components, and capabilities of our consortium's "open-source" large-scale (~1L/h) (129)Xe hyperpolarizer for clinical, pre-clinical, and materials NMR/MRI (Nikolaou et al., Proc. Natl. Acad. Sci. USA, 110, 14150 (2013)). The 'hyperpolarizer' is automated and built mostly of off-the-shelf components; moreover, it is designed to be cost-effective and installed in both research laboratories and clinical settings with materials costing less than $125,000. The device runs in the xenon-rich regime (up to 1800Torr Xe in 0.5L) in either stopped-flow or single-batch mode-making cryo-collection of the hyperpolarized gas unnecessary for many applications. In-cell (129)Xe nuclear spin polarization values of ~30%-90% have been measured for Xe loadings of ~300-1600Torr. Typical (129)Xe polarization build-up and T1 relaxation time constants were ~8.5min and ~1.9h respectively under our spin-exchange optical pumping conditions; such ratios, combined with near-unity Rb electron spin polarizations enabled by the high resonant laser power (up to ~200W), permit such high PXe values to be achieved despite the high in-cell Xe densities. Importantly, most of the polarization is maintained during efficient HP gas transfer to other containers, and ultra-long (129)Xe relaxation times (up to nearly 6h) were observed in Tedlar bags following transport to a clinical 3T scanner for MR spectroscopy and imaging as a prelude to in vivo experiments. The device has received FDA IND approval for a clinical study of chronic obstructive pulmonary disease subjects. The primary focus of this paper is on the technical/engineering development of the polarizer, with the explicit goals of facilitating the adaptation of design features and operative modes into other laboratories, and of spurring the further advancement of HP-gas MR applications in biomedicine., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Cells in the central nervous system rely almost exclusively on aerobic metabolism. Oxygen deprivation, such as injury-associated ischemia, results in detrimental apoptotic and necrotic cell loss. There is evidence that repetitive hyperbaric oxygen therapy (HBOT) improves outcomes in traumatic brain-injured patients. However, there are no experimental studies investigating the mechanism of repetitive long-term HBOT treatment-associated protective effects. We have therefore analysed the effect of long-term repetitive HBOT treatment on brain trauma-associated cerebral modulations using the lateral fluid percussion model for rats. Trauma-associated neurological impairment regressed significantly in the group of HBO-treated animals within three weeks post trauma. Evaluation of somatosensory-evoked potentials indicated a possible remyelination of neurons in the injured hemisphere following HBOT. This presumption was confirmed by a pronounced increase in myelin basic protein isoforms, PLP expression as well as an increase in myelin following three weeks of repetitive HBO treatment. Our results indicate that protective long-term HBOT effects following brain injury is mediated by a pronounced remyelination in the ipsilateral injured cortex as substantiated by the associated recovery of sensorimotor function.

The polymeric niche encountered by cells during primary culturing can affect cell fate. However, most cell types are primarily propagated on polystyrene (PS). A cell type specific screening for optimal primary culture polymers particularly for regenerative approaches seems inevitable. The effect of physical and chemical properties of treated (corona, oxygen/nitrogen plasma) and untreated cyclic olefin polymer (COP), polymethymethacrylate (PMMA), PP, PLA, PS, PC on neuronal stem cell characteristics was analyzed. Our comprehensive approach revealed plasma treated COP and PMMA as optimal polymers for primary neuronal stem cell culturing and propagation. An increase in the number of NT2/D1 cells with pronounced adhesion, metabolic activities and augmented expression of neural precursor markers was associated to the plasma treatment of surfaces of COP and PMMA with nitrogen or oxygen, respectively. A shift towards large cell sizes at stable surface area/volume ratios that might promote the observed increase in metabolic activities and distinct modulations in F-actin arrangements seem to be primarily mediated by the plasma treatment of surfaces. These results indicate that the polymeric niche has a distinct impact on various cell characteristics. The selection of distinct polymers and the controlled design of an optimized polymer microenvironment might thereby be an effective tool to promote essential cell characteristics for subsequent approaches.

Background and Purpose: MR imaging is currently not used to evaluate CSF flow changes due to short-lasting physiological maneuvers. The purpose of this study was to evaluate the ability of MR imaging to assess the CSF flow response to a Valsalva maneuver in healthy participants., Materials and Methods: A cardiac-gated fast cine-PC sequence with ≤15-second acquisition time was used to assess CSF flow in 8 healthy participants at the foramen magnum at rest, during, and immediately after a controlled Valsalva maneuver. CSF mean displacement volume VCSF during the cardiac cycle and CSF flow waveform App were determined. A work-in-progress real-time pencil-beam imaging method with temporal resolution ≤56 ms was used to scan 2 participants for 90 seconds during which resting, Valsalva, and post-Valsalva CSF flow, respiration, and HR were continuously recorded. Results were qualitatively compared with invasive craniospinal differential pressure measurements from the literature., Results: Both methods showed 1) a decrease from baseline in VCSF and App during Valsalva and 2) an increase in VCSF and App immediately after Valsalva compared with values measured both at rest and during Valsalva. Whereas fast cine-PC produced a single CSF flow waveform that is an average over many cardiac cycles, pencil-beam imaging depicted waveforms for each heartbeat and was able to capture many dynamic features of CSF flow, including transients synchronized with the Valsalva maneuver., Conclusions: Both fast cine-PC and pencil-beam imaging demonstrated expected changes in CSF flow with Valsalva maneuver in healthy participants. The real-time capability of pencil-beam imaging may be necessary to detect Valsalva-related transient CSF flow obstruction in patients with pathologic conditions such as Chiari I malformation.

The exquisite NMR spectral sensitivity and negligible reactivity of hyperpolarized xenon-129 (HP(129)Xe) make it attractive for a number of magnetic resonance applications; moreover, HP(129)Xe embodies an alternative to rare and nonrenewable (3)He. However, the ability to reliably and inexpensively produce large quantities of HP(129)Xe with sufficiently high (129)Xe nuclear spin polarization (P(Xe)) remains a significant challenge--particularly at high Xe densities. We present results from our "open-source" large-scale (∼1 L/h) (129)Xe polarizer for clinical, preclinical, and materials NMR and MRI research. Automated and composed mostly of off-the-shelf components, this "hyperpolarizer" is designed to be readily implementable in other laboratories. The device runs with high resonant photon flux (up to 200 W at the Rb D1 line) in the xenon-rich regime (up to 1,800 torr Xe in 500 cc) in either single-batch or stopped-flow mode, negating in part the usual requirement of Xe cryocollection. Excellent agreement is observed among four independent methods used to measure spin polarization. In-cell P(Xe) values of ∼90%, ∼57%, ∼50%, and ∼30% have been measured for Xe loadings of ∼300, ∼500, ∼760, and ∼1,570 torr, respectively. P(Xe) values of ∼41% and ∼28% (with ∼760 and ∼1,545 torr Xe loadings) have been measured after transfer to Tedlar bags and transport to a clinical 3 T scanner for MR imaging, including demonstration of lung MRI with a healthy human subject. Long "in-bag" (129)Xe polarization decay times have been measured (T1 ∼38 min and ∼5.9 h at ∼1.5 mT and 3 T, respectively)--more than sufficient for a variety of applications.

Microparticles are cell-derived, membrane-sheathed structures that are believed to shuttle proteins, mRNA, and miRNA to specific local or remote target cells. To date best described in blood, we now show that cerebrospinal fluid (CSF) contains similar structures that can deliver RNAs and proteins to target cells. These are, in particular, molecules associated with neuronal RNA granules and miRNAs known to regulate neuronal processes. Small RNA molecules constituted 50% of the shuttled ribonucleic acid. Using microarray analysis, we identified 81 mature miRNA molecules in CSF microparticles. Microparticles from brain injured patients were more abundant than in non-injured subjects and contained distinct genetic information suggesting that they play a role in the adaptive response to injury. Notably, miR-9 and miR-451 were differentially packed into CSF microparticles derived from patients versus non-injured subjects. We confirmed the transfer of genetic material from CSF microparticles to adult neuronal stem cells in vitro and a subsequent microRNA-specific repression of distinct genes. This first indication of a regulated transport of functional genetic material in human CSF may facilitate the diagnosis and analysis of cerebral modulation in an otherwise inaccessible organ.

Cell-therapy was proposed to be a promising tool in case of death or impairment of specific cell types. Correct identification of implanted cells became crucial when evaluating the success of transplantation therapy. Various methods of cell labeling have been employed in previously published studies. The use of intrinsic signaling of green fluorescent protein (GFP) has led to a well known controversy in the field of cardiovascular research. We encountered similar methodological pitfalls after transplantation of GFP-transfected embryonic stem cells into rat brains following traumatic brain injury (TBI). As the identification of implanted graft by intrinsic autofluorescence failed, anti-GFP labeling coupled to fluorescent and conventional antibodies was needed to visualize the implanted cells. Furthermore, different cell types with strong intrinsic autofluorescence were found at the sites of injury and transplantation, thus mimicking the implanted stem cells. GFP-positive stem cells were correctly localized, using advanced histological techniques. The activation of microglia/macrophages, accompanying the transplantation post TBI, was shown to be a significant source of artefacts, interfering with correct identification of implanted stem cells. Dependent on the strategy of stem cell tracking, the phagocytosis of implanted cells as observed in this study, might also impede the interpretation of results. Critical appraisal of previously published data as well as a review of different histological techniques provide tools for a more accurate identification of transplanted stem cells., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Purpose: To calculate age-related and per diopter (D) accommodative changes in crystalline lens and ciliary muscle dimensions in vivo in a single cohort of emmetropic human adults ages 30 to 50 years., Methods: The right eyes of 26 emmetropic adults were examined using ultrasonography, phakometry, anterior segment optical coherence tomography, and high resolution magnetic resonance imaging. Accommodation was measured both subjectively and objectively., Results: In agreement with previous research, older age was linearly correlated with a thicker lens, steeper anterior lens curvature, shallower anterior chamber, and lower lens equivalent refractive index (all P < 0.01). Age was not related to ciliary muscle ring diameter (CMRD) or lens equatorial diameter (LED). With accommodation, lens thickness increased (+0.064 mm/D, P < 0.001), LED decreased (-0.075 mm/D, P < 0.001), CMRD decreased (-0.105 mm/D, P < 0.001), and the ciliary muscle thickened anteriorly (+0.013 to +0.026 mm/D, P < 0.001) and thinned posteriorly (-0.011 to -0.015, P < 0.01). The changes per diopter of accommodation in LED, CMRD, and ciliary muscle thickness were not related to subject age., Conclusions: The per diopter ciliary muscle contraction is age independent, even as total accommodative amplitude declines. Quantifying normal biometric dimensions of the accommodative structures and changes with age and accommodative effort will further the development of new IOLs designed to harness ciliary muscle forces.

Purpose: To implement and characterize a single-breath xenon transfer contrast (SB-XTC) method to assess the fractional diffusive gas transport F in the lung: to study the dependence of F and its uniformity as a function of lung volume; to estimate local alveolar surface area per unit gas volume S(A)/V(Gas) from multiple diffusion time measurements of F; to evaluate the reproducibility of the measurements and the necessity of B(1) correction in cases of centric and sequential encoding., Materials and Methods: In SB-XTC three or four gradient echo images separated by inversion/saturation pulses were collected during a breath-hold in eight healthy volunteers, allowing the mapping of F (thus S(A)/V(Gas)) and correction for other contributions such as T(1) relaxation, RF depletion and B(1) inhomogeneity from inherently registered data., Results: Regional values of F and its distribution were obtained; both the mean value and heterogeneity of F increased with the decrease of lung volume. Higher values of F in the bases of the lungs in supine position were observed at lower volumes in all volunteers. Local S(A)/V(Gas) (with a mean ± standard deviation of S(A)/V(Gas) = 89 ± 30 cm(-1)) was estimated in vivo near functional residual capacity. Calibration of SB-XTC on phantoms highlighted the necessity for B(1) corrections when k-space is traversed sequentially; with centric ordering B(1) distribution correction is dispensable., Conclusion: The SB-XTC technique is implemented and validated for in vivo measurements of local S(A)/V(Gas)., (Copyright © 2012 Wiley Periodicals, Inc.)

A 33-year-old woman underwent a right-sided pneumonectomy in 1995 for treatment of a lung adenocarcinoma. As expected, there was an abrupt decrease in her vital capacity, but unexpectedly, it increased during the subsequent 15 years. Serial computed tomographic (CT) scans showed progressive enlargement of the remaining left lung and an increase in tissue density. Magnetic resonance imaging (MRI) with the use of hyperpolarized helium-3 gas showed overall acinar-airway dimensions that were consistent with an increase in the alveolar number rather than the enlargement of existing alveoli, but the alveoli in the growing lung were shallower than in normal lungs. This study provides evidence that new lung growth can occur in an adult human.

Background: The ratio of high amyloid-β peptide40 (Aβ40) and low Aβ42 in plasma predicts the risk of Alzheimer's disease (AD) and is associated with episodic recall in depression. We thus examined the relationship between plasma Aβ levels and brain volumes., Methods: Homebound elders (N = 352) who had undergone brain MRI were used. Plasma Aβ1-40 and Aβ1-42 were measured by ELISA. Volumes of medial temporal regions, including the amygdala and hippocampus, were manually measured., Results: Amygdala volume was associated with log(10) of plasma Aβ1-42 (β = +0.19, SE = 0.07, p = 0.005) after adjusting for AD, infarcts, white matter hyperintensities and demographics. In the absence of dementia, decreasing quartiles of plasma Aβ1-42 (Mean + SD ml: Q4 = 4.1 ± 0.8; Q3 = 3.9 ± 0.7; Q2 = 3.6 ± 0.8 and Q1 = 3.7 ± 0.8, p = 0.01) and increasing quartiles of plasma Aβ1-40/1-42 ratio were associated with smaller amygdala volume. Those depressed subjects with a high plasma Aβ1-40/1-42 ratio had smaller amygdala (Mean + SD ml: 3.3 ± 0.8 vs. 3.6 ± 0.8, p = 0.04) and total brain volume (Mean + SD liter: 0.95 ± 0.07 vs. 1.04 ± 0.12, p = 0.005), and had a higher rate of MCI (67 vs. 36%, p = 0.02) than those with a low plasma Aβ1-40/1-42 ratio., Conclusions: The combination of low plasma Aβ1-42 concentration and atrophy of the medial temporal lobe structures, which regulates mood and cognition, may represent a biomarker for a prodromal stage of AD., (Copyright © 2010 John Wiley & Sons, Ltd.)

The purpose of this study was to analyze the CSF flow in patients with Chiari I to determine differences between patients with and without CAH. Thirty patients with Chiari I malformation underwent cine-PC CSF flow imaging in the sagittal plane. CSF flow pulsations were analyzed by placing regions of interest in the anterior cervical subarachnoid space. Maximum CSF systolic (craniocaudal) and diastolic (caudocranial) velocities as well as the durations of CSF systole and diastole (measured in fractions of the cardiac cycle) were determined. In the region of interest just below the foramen magnum, patients with CAH had a significantly shorter CSF systole and longer diastole (P=.02). A CSF diastolic length of ≥0.75 of the cardiac cycle was 67% sensitive and 86% specific for CAH. Our results indicate that Cine-PC imaging can show differences in CSF flow patterns in patients with Chiari I with and without CAH.

Punctate reopening of the lung from subresidual volumes (sub-RV) is commonly observed in excised lung preparations, either degassed or collapsed to zero transpulmonary pressure, and in the course of reinflation of human lungs when the chest is open, secondary to traumatic or surgical pneumothoraxes. In the course of physiological studies on two elite breath-hold divers, who are able to achieve lung volumes well below traditional RV with glossopharyngeal exsufflation, we used MRI lung imaging with inhaled hyperpolarized (129)Xe to visualize ventilatory patterns. We observed strikingly inhomogeneous inhalation patterns with small inhalation volumes from sub-RV, consistent with reopening of frankly closed airways. On the other hand, two age-matched and two older controls, inhaling from just above RV, showed a much more homogeneous pattern. Our results demonstrate the concept of frank airway closure below RV in young healthy adults with an intact chest wall.

The time-dependence of the NMR signal intensity of collagen type I is representative of protein aggregation. It is pH sensitive and can be related to aggregation mechanism.

Objective: The purpose of this study was to evaluate the relation between bronchial wall attenuation on thin-section CT images and airflow limitation in persons with chronic obstructive pulmonary disease., Subjects and Methods: One hundred fourteen subjects (65 men, 49 women; age range, 56-74 years) enrolled in the National Lung Screening Trial underwent chest CT and prebronchodilation spirometry at a single institution. At CT, mean peak wall attenuation, wall area percentage, and luminal area were measured in the third, fourth, and fifth generations of the right B(1) and B(10) segmental bronchi. Correlations with forced expiratory volume in the first second of expiration (FEV(1)) expressed as percentage of predicted value were evaluated with Spearman's rank correlation test., Results: The peak wall attenuation of each generation of segmental bronchi correlated significantly with FEV(1) as percentage of predicted value (B(1) third, r = -0.323, p = 0.0005; B(1) fourth, r = -0.406, p < 0.0001; B(1) fifth, r = -0.478, p < 0.0001; B(10) third, r = -0.268, p = 0.004; B(10) fourth, r = -0.476, p < 0.0001; B(10) fifth, r = -0.548, p < 0.0001). The correlation coefficients were higher in peripheral airway generations. Wall area percentage and luminal area had similar significant correlations. In multivariate analysis to predict FEV(1) as percentage of predicted value, the coefficient of determination of the model with the combination of percentage of low-attenuation area (< -950 HU) and peak wall attenuation of the fifth generation of the right B(10) was 0.484; the coefficient of determination with percentage of low-attenuation area and wall area percentage was 0.40., Conclusion: Peak attenuation of the bronchial wall measured at CT correlates significantly with expiratory airflow obstruction in subjects with chronic obstructive pulmonary disease, particularly in the distal airways.

This study focused on the program experiences of 190 men and women who chose to participate in a drug treatment court in lieu of incarceration in California. Participants had committed non-violent criminal offenses related to drug abuse. The program required 18 months of community-based treatment in conjunction with court supervision including frequent drug testing and 6 months of abstinence for successful program completion. Interviews were conducted in 2007/2008 with 94 participants who had successfully completed treatment and 96 who had not. Open-ended questions addressed reasons for entering and remaining in treatment and supports and obstacles to program completion. Responses were coded using ethnographic content analysis. Factors associated with successful program completion are discussed.

Wagner's (2001) Logical Rorschach (LR) was designed to be a simple but reliable and valid system for assessing psychological distress and cognitive slippage using the Rorschach Inkblot Method (Exner, 2003). In this investigation, we administered the Rorschach to 50 adults with and without trauma histories. Scoring of the test followed both the Comprehensive System (CS; Exner, 2003) and the LR guidelines. Results indicate that the Perceptual Thinking Index (Exner, 2000, 2003), the CS-derived Trauma Content Index (Armstrong & Loewenstein, 1990) and Aggressive Past (Gacono & Meloy, 1994), and the LR Perceptual Accuracy Score (Wagner, 2001) scores were able to differentiate the 2 groups. Despite largely equivocal findings, it appears that some aspects of the LR may have some validity in the assessment of trauma-related phenomena.

Rationale and Objectives: Pulmonary vascular alteration is one of the characteristic features of chronic obstructive pulmonary disease (COPD). Recent studies suggest that vascular alteration is closely related to endothelial dysfunction and may be further influenced by emphysema. However, the relationship between morphological alteration of small pulmonary vessels and the extent of emphysema has not been assessed in vivo. The objectives of this study are: to evaluate the correlation of total cross-sectional area (CSA) of small pulmonary vessels with the extent of emphysema and airflow obstruction using CT scans and to assess the difference of total CSA between COPD phenotypes., Materials and Methods: We measured CSA less than 5 mm(2) and 5-10 mm(2), and calculated the percentage of the total CSA for the lung area (%CSA < 5, and %CSA5-10, respectively) using CT scans in 191 subjects. The extent of emphysema (%LAA-950) was calculated, and the correlations of %CSA < 5 and %CSA5-10 with %LAA-950 and results of pulmonary function tests (PFTs) were evaluated. The differences in %CSA between COPD phenotypes were also assessed., Results: The %CSA < 5 had significant negative correlations with %LAA-950 (r = -0.83, P < .0001). There was a weak but statistically significant correlation of %CSA < 5 with forced expiratory volume in 1 second (FEV1)% predicted (r = 0.29, P < .0001) and FEV1/forced vital capacity (r = 0.45, P < .0001). A %CSA 5-10 had weak correlations with %LAA-950 and results of PFTs. %CSA < 5 was significantly higher in bronchitis phenotype than in the emphysema phenotype (P < .0001)., Conclusions: Total CSA of small pulmonary vessels at sub-subsegmental levels strongly correlates with the extent of emphysema (%LAA-950) and reflects differences between COPD phenotypes.

Dramatic cerebral responses following brain injury (TBI) comprise inflammation, cell death, and modulation of trophic factor release. These cerebral modulations might induce and/or attenuate acute neuronal damage. Here, we investigated the effect of tissue extract derived from healthy (HBE) or injured rat brain (TBE) on the differentiation of cultured embryonic stem cells in vitro. Rats were sacrificed at t = 45 minutes following lateral fluid-percussion injury and extracts of cerebral tissue were prepared from 4-6 healthy or injured rat brain hemispheres. Murine embryonic stem cells (CGR8) cultured in serum-free medium were then conditioned for a week with HBE or TBE. Omission of serum from the culture medium induced neural differentiation of CGR8 stem cells, as indicated by a significant time dependent down-regulation of oct-4 with a concomitant upregulation of nestin after 7 days. In parallel cell loss was observed that seemed to be largely due to apoptotic cell death. In TBE treated cells, on the other hand, a significant amplification of apoptotic cell death, enhancement of nestin and MAP2 expression and marked morphological changes such as axonal-like outgrowth was observed within 3 days of conditioning. Treatment of stem cells with HBE resulted in less pronounced neuronal differentiation processes. Axonal-like outgrowth was not observed. Our data suggest that during the early acute phase of traumatic injury the cerebral environment is disposed to detrimental as well as potent protective signals that seem to rapidly induce neurogenic processes., (Copyright © 2010 S. Karger AG, Basel.)

The synRas transgenic mice express constitutively activated Valin12-Harvey Ras in postnatal neocortical pyramidal neurons. This leads to somatodendritic hypertrophy, higher densities of spines and synapses, and an enhancement of synaptic long-term potentiation associated with an increased glutamate receptor-mediated activity. It was less clear how the interneurons respond to these alterations, and this prompted the quantitative assessment of interneuron neurochemistry. Interneurons rarely expressed the transgene, however, several interneuron types displayed a transient somatic hypertrophy. Furthermore, NPY mRNA expression was persistently increased as were the laminar percentages of labeled neurons. The expression of parvalbumin and voltage-gated potassium channels Kv3.1b/3.2 was unchanged. A significant decline of GAD-67, but not GAD-65, mRNA expressing neurons was observed in layer VI in animals older than P60. This suggested that subtle deficits in inhibition and enhanced excitation evoke the interneuronal changes in the synRastransgenic mouse cortex., (© Springer-Verlag 2008)

The (13)C NMR signal of acetic acid 1-(13)C-AcH is enhanced by polarization transfer from hyperpolarized (129)Xe using a thermal mixing procedure. 1-(13)C-AcH acid and hyperpolarized (129)Xe are mixed as gases to disperse (129)Xe in the acetic acid. The mixture is frozen with liquid N(2) at 0.5 T. The magnetic field is then momentarily dropped to allow for exchange of spin polarization between (13)C and (129)Xe. After polarization exchange the magnetic field is raised to its original value and the mixture is thawed, resulting in a solution of polarization enhanced 1-(13)C-AcH. A (13)C nuclear spin polarization enhancement of 10 is observed compared to its thermal polarization at 4.7 T. This polarization enhancement is approximately three orders of magnitude lower than that predicted by theory. The discrepancy is attributed to the formation of either an inhomogeneous solid matrix and/or spin dynamics during polarization transfer. Despite the low polarization enhancement, this is the first report of polarization transfer from (129)Xe to (13)C nuclear spins achieved by thermal mixing for a proton-containing molecule of biomedical importance. If future work can increase the enhancement, this method will be useful in hyperpolarizing a wide range of (13)C enriched compounds important in biomedical and biophysical research.

Rationale and Objectives: The authors present their initial experience using a 3-T whole-body scanner equipped with a 128-channel coil applied to lung motion assessment. Recent improvements in fast magnetic resonance imaging (MRI) technology have enabled several trials of free-breathing three-dimensional (3D) imaging of the lung. A large number of image frames necessarily increases the difficulty of image analysis and therefore warrants automatic image processing. However, the intensity homogeneities of images of prior dynamic 3D lung MRI studies have been insufficient to use such methods. In this study, initial data were obtained at 3 T with a 128-channel coil that demonstrate the feasibility of acquiring multiple sets of 3D pulmonary scans during free breathing and that have sufficient quality to be amenable to automatic segmentation., Materials and Methods: Dynamic 3D images of the lungs of two volunteers were acquired with acquisition times of 0.62 to 0.76 frames/s and an image matrix of 128 x 128, with 24 to 30 slice encodings. The volunteers were instructed to take shallow and deep breaths during the scans. The variation of lung volume was measured from the segmented images., Results: Dynamic 3D images were successfully acquired for both respiratory conditions for each subject. The images showed whole-lung motion, including lifting of the chest wall and the displacement of the diaphragm, with sufficient contrast to distinguish these structures from adjacent tissues. The average time to complete segmentation for one 3D image was 4.8 seconds. The tidal volume measured was consistent with known tidal volumes for healthy subjects performing deep-breathing maneuvers. The temporal resolution was insufficient to measure tidal volumes for shallow breathing., Conclusion: This initial experience with a 3-T whole-body scanner and a 128-channel coil showed that the scanner and imaging protocol provided dynamic 3D images with spatial and temporal resolution sufficient to delineate the diaphragmatic domes and chest wall during active breathing. In addition, the intensity homogeneities and signal-to-noise ratio were adequate to perform automatic segmentation.

Rationale and Objectives: Using a novel (129)Xe polarizer with high throughput (1-2 L/hour) and high polarization (approximately 55%), our objective was to demonstrate and characterize human pulmonary applications at 0.2T. Specifically, we investigated the ability of (129)Xe to measure the alveolar surface area per unit volume of gas, S(A)/V(gas)., Materials and Methods: Variable spin echo time (TE) gradient and radiofrequency (RF) echoes were used to obtain estimates of the lung's contribution to both T(2)* and T(2). Standard multislice ventilation images were obtained and signal-to-noise ratio (SNR) determined. Whole-lung, time-dependent measurements of (129)Xe diffusion from gas to septal tissue were obtained with a chemical shift saturation recovery (CSSR) method. Four healthy subjects were studied, and the Butler et al CSSR formalism (J Phys Condensed Matter 2002; 14:L297-L304) was used to calculate S(A)/V(gas). A single-breath version of the xenon transfer contrast (SB-XTC) method was implemented and used to image (129)Xe diffusion between alveolar gas and septal tissue. A direct comparison of CSSR and SB-XTC was performed., Results: T(2)*=135+/-29 ms amd T(2)=326.2+/-9.5 ms. Maximum SNR=36 for ventilation images from inhalation of 1L 86% (129)Xe and voxel volume =0.225 mL. CSSR analysis showed S(A)/V(gas) decreased with increasing lung volume in a manner very similar to that observed from histology measurements; however, the absolute value of S(A)/V(gas) was approximately 40% smaller than histology values. SB-XTC images in different postures demonstrate gravitationally dependent values. Initial comparison of CSSR with XTC showed fairly good agreement with expected ratios., Conclusions: Hyperpolarized (129)Xe human imaging and spectroscopy are very promising methods to provide functional information about the lung.

Recent development of MR techniques has overcome many problems, such as susceptibility artifacts or motion artifact, allowing both static and dynamic MR lung imaging and providing quantitative information of pulmonary function, including perfusion, ventilation, and respiratory motion. Dynamic contrast-enhanced MR perfusion imaging is suitable for the evaluation of angiogenesis of pulmonary solitary nodules. (129)Xe MR imaging is potentially a robust technique for the evaluation of various pulmonary function and may replace (3)He. The information provided by these new MR imaging methods is proving useful in research and in clinical applications in various lung diseases.

The majority of researchers investigating hyperpolarized gas MRI as a candidate functional lung imaging modality have used (3)He as their imaging agent of choice rather than (129)Xe. This preference has been predominantly due to, (3)He providing stronger signals due to higher levels of polarization and higher gyromagnetic ratio, as well as its being easily available to more researchers due to availability of polarizers (USA) or ease of gas transport (Europe). Most researchers agree, however, that hyperpolarized (129)Xe will ultimately emerge as the imaging agent of choice due to its unlimited supply in nature and its falling cost. Our recent polarizer technology delivers vast improvements in hyperpolarized (129)Xe output. Using this polarizer, we have demonstrated the unique property of xenon to measure alveolar surface area noninvasively. In this article, we describe our human protocols and their safety, and our results for the measurement of the partial pressure of pulmonary oxygen (pO(2)) by observation of (129)Xe signal decay. We note that the measurement of pO(2) by observation of (129)Xe signal decay is more complex than that for (3)He because of an additional signal loss mechanism due to interphase diffusion of (129)Xe from alveolar gas spaces to septal tissue. This results in measurements of an equivalent pO(2) that accounts for both traditional T(1) decay from pO(2) and that from interphase diffusion. We also provide an update on new technological advancements that form the foundation for an improved compact design polarizer as well as improvements that provide another order-of-magnitude scale-up in xenon polarizer output.

The accumulation and aggregation of fragments of amyloid precursor protein (APP) are central to the development of Alzheimer's disease. The production of the small fragment C99 is thought to form the rate-limiting step in the APP processing pathway, which can lead to the production of the toxic Abeta peptide. It has also been suggested that the proteasome contributes to APP catabolism. While the identities and aggregation propensities of many APP fragments have been studied in vitro, the sequences, structures, and cellular sources of fragments generated in vivo remains poorly elucidated. To better identify the specific APP fragments generated in vivo and to elucidate the role of the proteasome in APP processing, we developed a C99 yeast expression system. Using Zip Tip immunocapture, a specific anti-Abeta antiserum (6E10), and matrix-assisted laser desorption ionization- time of flight mass spectrometry, we identified over one dozen APP-generated peptide fragments in wild-type yeast (PRE1PRE2) and over three dozen unique fragments in proteasome mutant cells (pre1- 1pre2-1) expressing C99. Based on the identities of the immunocaptured species, we propose that defects in proteasome function are compensated by other proteases and that the combination of techniques described here will be invaluable to further delineate the APP processing pathway in vivo.

Purpose: To measure T(1) and T(2) of the fine structures of the in vivo eye., Materials and Methods: Involuntary saccades make it difficult to obtain artifact-free images. Using a method recently reported (Bert et al, Acad Radiol 2006;12:368-378), near artifact-free spin-echo images were obtained. Both an isolated enucleated eye and eight human subjects were studied at 1.5 T. Spin-echo variable TR/TE data was acquired for T(1)/T(2) determination. Average relaxation times were calculated two ways. First, an arithmetic average over different subjects was computed. Second, all data was normalized using the fitted amplitudes of each data set and pooled to obtain a single least squares fit., Results: In vivo T(1)/T(2) (msec) are: arithmetic average T(1), T(2), normalized data T(1), T(2). Anterior chamber: 6233 +/- 979, 468 +/- 149, 5053 +/- 1052, 450 +/- 49. Ciliary body: 1916 +/- 184, 80 +/- 7, 2038 +/- 114, 76 +/- 3. Chorioretina: 1717 +/- 500, 72 +/- 25, 1511 +/- 230, 78 +/- 3. Extraocular muscle: 1581 +/- 646, 41 +/- 7, 1470 +/- 231, 41 +/- 1. Iris: 3334 +/- 989, 163 +/- 63, 3376 +/- 338, 153 +/- 10. Lens cortex: 1712 +/- 466, 93 +/- 36, 1413 +/- 177, 100 +/- 5. Lens nucleus: 1133 +/- 40, 26 +/- 3, 1138 +/- 47, 25 +/- 0.4. Optic nerve: 1906 +/- 301, 68 +/- 16, 1805 +/- 244, 71 +/- 2. Posterior chamber: 7915 +/- 4897, 241 +/- 14, 3323 +/- 2154, 251 +/- 38. Vitreous humor: 5768 +/- 1190, 756 +/- 804, 4855 +/- 1846, 390 +/- 8., Conclusion: In vivo T(1) and T(2) for many of the fine structures of the human eye have been measured., ((c) 2007 Wiley-Liss, Inc.)

Purpose: The present studies were conducted to determine whether a diffusional pathway for solutes exists from the ciliary body stroma to the anterior chamber of the human eye. The existence of such a pathway has been demonstrated in rabbits and monkeys, but such a pathway in humans would necessitate a shift in the physiological paradigm of the blood-aqueous barrier., Methods: Seven normal human volunteers (five men, two women; age range, 27 to 59 years) underwent nine dynamic T1-weighted, spin-echo MR imaging studies, using intravenous, gadolinium-based contrast agents., Results: In all cases, signal intensity rose rapidly in the ciliary body. In all subjects, there was a measurable latent rise in signal strength (enhancement) in the anterior chamber. Signal enhancement typically occurred in the angle of the anterior chamber earlier, and to a greater degree, than within the center of the chamber. Increased signal within the posterior chamber was significantly less than in the anterior chamber, with measured increases probably attributable to volume averaging., Conclusions: These findings are consistent with the existence of an anterior diffusional pathway in the human eye. The model warrants further testing.

The distribution of mRNA for the rho2 subunit of the GABA(C) receptor is much broader in organotypic SC cultures than in vivo, suggesting that GABA(C) receptor expression is regulated by environmental factors. Electrophysiological recordings indicate that neurons in SC cultures have functional GABA(C) receptors, although these receptors exhibited smaller conductance than in vivo, probably due to increased rho2 subunit expression. Adding cortical input, treatment with various neuromodulators, and blocking neuronal activity with TTX failed to affect the expression of rho2 subunits. Electrophysiological recordings revealed the presence of spontaneous Ca(2+) currents in SC cultures and preventing these, by treatment with blockers of L-type Ca(2+) channels, caused rho2 mRNA expression to decline to in vivo levels. In contrast, rho1 subunit mRNA levels remained unchanged, indicating that the two subunits are independently regulated. Surprisingly, both tonic activation and blockade of GABA(C) receptors upregulated rho1/rho2 mRNA expression. Further, NGF and BDNF promoted such expression during an early postnatal time window. In vivo, expression of the rho2 mRNA in the SC, and the rho2/rho3 mRNA in the retina increased with age. Expression of the rho2 mRNA in the visual cortex, and the rho1 mRNA in the retina and SC was constant. Subunit mRNA expression was similar in dark-reared animals, indicating that visual experience has no influence. These experiments suggest that GABA(C) receptor expression in the SC is regulated during postnatal development. While visual experience seems to have no influence on GABA(C) receptor subunits, spontaneous calcium currents selectively promote rho2 expression and both rho1 and rho2 are autoregulated both by GABA(C) receptor activity and by neurotrophic factors.

Neurotrophins are essential factors for the structural, neurochemical and functional maturation of the brain including developmental and adult plasticity. Northern blots and polymerase chain reaction revealed the expression of neurotrophin 4 (NT4), neurotrophin 3 (NT3), brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) in the cortex. The cellular producers of NT3 and BDNF have been characterized by anatomical methods as being mostly pyramidal, and the tyrosine kinase B (TrkB) receptor is expressed by many cortical neurons. However, these methods have so far failed to identify the cells producing NT4 and NGF mRNA. These factors are much lower in expression than, e.g. BDNF, and apparently remain below detection levels of in situ hybridization. Given their specific actions on cell types and afferent systems, knowledge about the producing cell types is highly desirable. To narrow down on the producing cell types, we quantified by reverse transcriptase-polymerase chain reaction (RT-PCR) the developmental changes of BDNF, NT3, NT4, NGF and TrkB mRNA expression in total visual cortex lysates, and in the cortical layers dissected by tangential cryostat sectioning. We found dramatic changes in laminar expression of NT3 and NGF, mild changes of NT4, and no changes of BDNF and TrkB mRNA. For instance, NT3 is important early on for thalamocortical axons, and we found transient peaks of NT3 mRNA expression first in layer VI, then in layer IV. NT4 mRNA was in layers IV and VI, suggesting NT4 protein production in thalamorecipient layers, but peak expression gradually shifted to upper layers as did NGF expression. The layer-specific developmental expression shifts of neurotrophin mRNAs correlate with morphogenetic processes.

The association between orbital frontal cortex (OFC) volume and aggression and impulsivity was investigated among a heterogeneous group of non-psychotic psychiatric clients. Fifteen non-psychotic subjects from two different psychiatric clinics (New England Medical Center and Lemuel Shattuck Hospital) with a variety of diagnoses were sequentially referred for magnetic resonance imaging (MRI) for clinical purposes. This convenience sample, clinically stable at the time of evaluation, received a standardized psychiatric diagnostic interview, aggression and impulsivity psychometrics (Barratt Impulsivity, Lifetime History of Aggression, and Buss-Perry Aggression scales), and an MRI protocol with image analysis. OFC gray matter volume, total as well as left and right, was significantly and positively associated with motor impulsivity. OFC asymmetry was associated with aggression, though total, left, and right OFC volume measurements were not. For subjects without affective disorder, there was a strong and positive association of the OFC to motor and no-planning subscales of the Barratt Impulsivity Scale. For subjects with affective disorder, there was a strong association of OFC asymmetry to both of the aggression psychometrics. Consistent with expectation, results are suggestive of OFC involvement in the neural circuitry of impulsivity and aggression. The findings suggest a dissociation of the role of the OFC in relation to aggression and impulsivity, such that the OFC may play a part in the regulation of aggressive behavior and a generative role in impulsive behavior.

Background: Micronutrient status can affect cognitive function in the elderly; however, there is much to learn about the precise effects. Understanding mediating factors by which micronutrient status affects cognitive function would contribute to elders' quality of life and their ability to remain in the home., Objectives: The Nutrition, Aging, and Memory in Elders (NAME) Study is designed to advance the current level of knowledge by investigating potential mediating factors by which micronutrient status contributes to cognitive impairment and central nervous system abnormalities in the elderly. NAME targets homebound elders because they are understudied and particularly at risk for poor nutritional status., Methods: Subjects are community-based elders aged 60 and older, recruited through area Aging Services Access Points. The NAME core data include demographics; neuropsychological testing and activities of daily living measures; food frequency, health and behavioral questionnaires; anthropometrics; gene status; plasma micronutrients, homocysteine, and other blood determinants. A neurological examination, psychiatric examination, and brain MRI and volumetric measurements are obtained from a sub-sample., Results: Preliminary data from first 300 subjects are reported. These data show that the NAME protocol is feasible and that the enrolled subjects are racially diverse, at-risk, and had similar basic demographics to the population from which they were drawn., Conclusion: The goal of the NAME study is to evaluate novel relationships between nutritional factors and cognitive impairment. These data may provide important information on potential new therapeutic strategies and supplementation standards for the elderly to maintain cognitive function and potentially reduce the public health costs of dementia.

The purpose of this research was to reassess the effects of topical pilocarpine on the integrity of the blood-aqueous barrier, using high resolution, magnetic resonance imaging, and the standard intravenous contrast agent gadolinium dimeglumine. It has long been known that topical pilocarpine gives rise to an increase in protein levels in the anterior chamber of the eye. This protein scatters light and is referred to clinically as 'flare'. Prior studies concluded that pilocarpine-induced flare resulted from disruption of the blood-aqueous barrier. These studies relied upon indirect methods that precluded direct visualization of the posterior chamber of the eye. Five normal, human volunteers (age 22-40) received a single drop of 3% pilocarpine in one eye, following baseline measurements of pupil size and anterior chamber 'flare'. These measurements were repeated every 15 min for 45 min. The subject was then positioned in the magnet and the eye that received pilocarpine was taped closed and covered with a 3 in.-diameter receive-only surface coil. The open contralateral eye focused on a target to maintain fixation of the imaged eye. A baseline image of the eye was obtained and the contrast agent was administered intravenously. A series of additional images was obtained during the following 60 min to track the movement of contrast material from the bloodstream into the tissues and compartments of the eye. Percent enhancement was calculated from selected regions of interest in the images, including the ciliary body, and the anterior and posterior chambers. Within the 45 min after administration of pilocarpine, pupil size in mm decreased from (mean+/-s.d.) 5.7+/-1.5 to 2.5+/-0.5 (p=0.0106). During this period, average flare/s.d. (photons msec-1) increased from 3.7+/-1.1 to 12.5+/-4.7 (p=0.0151). In all cases, MRI images showed rapid enhancement of the ciliary body, followed by a progressive increase in signal in the anterior chamber but not the posterior chamber. These studies confirm that topical pilocarpine gives rise to 'flare' in the anterior chamber. But the lack of enhancement in the posterior chamber strongly suggests that the presence of this added protein in the anterior chamber is not the result of increased permeability of the blood-aqueous barrier of the ciliary body. These studies also introduce the novel concept that not all clinically observed flare is the result of blood-aqueous barrier compromise.