Progression of alpha-synuclein pathology in multiple system atrophy of the cerebellar type.

AIMS: The aim of this study was to identify early foci of α-synuclein (α-syn pathology) accumulation, subsequent progression and neurodegeneration in multiple system atrophy of the cerebellar type (MSA-C). METHODS: We analysed 70-µm-thick sections of 10 cases with MSA-C and 24 normal controls. RESULTS: MSA-C cases with the lowest burden of pathology showed α-syn glial cytoplasmic inclusions (GCIs) in the cerebellum as well as in medullary and pontine cerebellar projections. Cerebellar pathology was highly selective and severely involved subcortical white matter, whereas deep white matter and granular layer were only mildly affected and the molecular layer was spared. Loss of Purkinje cells increased with disease duration and was associated with neuronal and axonal abnormalities. Neocortex, basal ganglia and spinal cord became consecutively involved with the increasing burden of α-syn pathology, followed by hippocampus, amygdala, and, finally, the visual cortex. GCIs were associated with myelinated axons, and the severity of GCIs correlated with demyelination. CONCLUSIONS: Our findings indicate that cerebellar subcortical white matter and cerebellar brainstem projections are likely the earliest foci of α-syn pathology in MSA-C, followed by involvement of more widespread regions of the central nervous system and neurodegeneration with disease progression.

Provision of home mechanical ventilation and sleep services for England survey.

The Department of Health is promoting the generation of specialist networks to manage long term ventilatory weaning and domiciliary non-invasive ventilation patients. Currently the availability of these services in England is not known. We performed a short survey to establish the prevalence of sleep and ventilation diagnostic and treatment services. The survey focussed on diagnostic services and Home Mechanical Ventilation (HMV) provision, and was divided into (a) availability of diagnostics, (b) funding, and (c) patient groups. This survey has confirmed that the majority of Home Mechanical Ventilation set-ups are currently for Obesity Related Respiratory Failure and Chronic Obstructive Pulmonary Disease. We have found that there is variable provision of diagnostic services, with the majority of units offering overnight oximetry (95%) but only 55% of responders providing a home mechanical ventilation service. Even more interestingly, less than two thirds of units charged their primary care trust for this service. These data may assist in the development of regional networks and specialist home mechanical ventilation centres.

Parallel computing in biomedical research.

Scalable parallel computer architectures provide the computational performance needed for advanced biomedical computing problems. The National Institutes of Health have developed a number of parallel algorithms and techniques useful in determining biological structure and function. These applications include processing electron micrographs to determine the three-dimensional structure of viruses, calculating the solvent-accessible surface area of proteins to help predict the three-dimensional conformation of these molecules from their primary structures, and searching for homologous DNA or amino acid sequences in large biological databases. Timing results demonstrate substantial performance improvements with parallel implementations compared with conventional sequential systems.

Ret Signaling Is Required for Tooth Pulp Innervation during Organogenesis.

During organogenesis, the timing and patterning of dental pulp innervation require both chemoattractive and chemorepellent cues for precise spatiotemporal regulation. Our understanding of the signaling mechanisms that regulate tooth innervation during development, as well as the basic biology of these sensory neurons, remains rudimentary. In this study, we analyzed the expression and function of glial cell line-derived neurotrophic factor (GDNF) and its receptor tyrosine kinase, Ret, in the regulation of innervation of the mouse tooth pulp by dental pulpal afferent (DPA) neurons of the trigeminal ganglion (TG). Using reporter mouse models, we demonstrate that Ret is highly expressed by a subpopulation of DPA neurons projecting to the tooth pulp at both postnatal day 7 (P7) and in the adult. In the adult tooth, GDNF is highly expressed by many cell types throughout the dental pulp. Using a ubiquitous tamoxifen (TMX)-inducible Cre ( UBC-Cre/ERT2) line crossed to Ret conditional knockout mice ( Retfx/fx), Ret was deleted immediately prior to tooth innervation, and the neural projections into P7 molars were analyzed. TMX treatment was efficient in ablating >95% of Ret protein. We observed that UBC-Cre/ERT2; Retfx/fx mice had a significant reduction in the total number of neurites present within the pulp at P7, with a significant accumulation of aberrant fibers in the dental follicle and periodontium. In agreement with these findings, inhibition of Ret signaling through in vivo administration of a highly specific pharmacologic inhibitor (1NM-PP1) of Ret also caused a substantial reduction in pulpal innervation. Taken together, these findings indicate that Ret signaling regulates the timing and patterning of tooth innervation by dental primary afferent neurons of the TG during organogenesis and provide a rationale to explore whether alterations in the GDNF-Ret pathway contribute to pathophysiological conditions in the adult dentition.

An intestine-specific homeobox gene regulates proliferation and differentiation.

Precise regulation of cellular proliferation, differentiation, and senescence results in the continuous renewal of the intestinal epithelium with maintenance of a highly ordered tissue architecture. Here we show that an intestine-specific homeobox gene, Cdx2, is a transcription factor that regulates both proliferation and differentiation in intestinal epithelial cells. Conditional expression of Cdx2 in IEC-6 cells, an undifferentiated intestinal cell line, led to arrest of proliferation for several days followed by a period of growth resulting in multicellular structures containing a well-formed columnar layer of cells. The columnar cells had multiple morphological characteristics of intestinal epithelial cells. Enterocyte-like cells were polarized with tight junctions, lateral membrane interdigitations, and well-organized microvilli with associated glycocalyx located at the apical pole. Remarkably, there were also cells with a goblet cell-like ultrastructure, suggesting that two of the four intestinal epithelial cell lineages may arise from IEC-6 cells. Molecular evidence for differentiation was shown by demonstrating that cells expressing high levels of Cdx2 expressed sucrase-isomaltase, an enterocyte-specific gene which is a well-defined target for the Cdx2 protein. Taken together, our data suggest that Cdx2 may play a role in directing early processes in intestinal cell morphogenesis and in the maintenance of the differentiated phenotype by supporting transcription of differentiated gene products. We propose that Cdx2 is part of a regulatory network that orchestrates a developmental program of proliferation, morphogenesis, and gene expression in the intestinal epithelium.

Base pairing between the 3' exon and an internal guide sequence increases 3' splice site specificity in the Tetrahymena self-splicing rRNA intron.

It has been proposed that recognition of the 3' splice site in many group I introns involves base pairing between the start of the 3' exon and a region of the intron known as the internal guide sequence (R. W. Davies, R. B. Waring, J. Ray, T. A. Brown, and C. Scazzocchio, Nature [London] 300:719-724, 1982). We have examined this hypothesis, using the self-splicing rRNA intron from Tetrahymena thermophila. Mutations in the 3' exon that weaken this proposed pairing increased use of a downstream cryptic 3' splice site. Compensatory mutations in the guide sequence that restore this pairing resulted in even stronger selection of the normal 3' splice site. These changes in 3' splice site usage were more pronounced in the background of a mutation (414A) which resulted in an adenine instead of a guanine being the last base of the intron. These results show that the proposed pairing (P10) plays an important role in ensuring that cryptic 3' splice sites are selected against. Surprisingly, the 414A mutation alone did not result in activation of the cryptic 3' splice site.

A homeodomain protein related to caudal regulates intestine-specific gene transcription.

The continually renewing epithelium of the intestinal tract arises from the visceral endoderm by a series of complex developmental transitions. The mechanisms that establish and maintain the processes of cellular renewal, cell lineage allocation, and tissue restriction and spatial assignment of gene expression in this epithelium are unknown. An understanding of the regulation of intestine-specific gene regulation may provide information on the molecular mechanisms that direct these processes. In this regard, we show that intestine-specific transcription of sucrase-isomaltase, a gene that is expressed exclusively in differentiated enterocytes, is dependent on binding of a tissue-specific homeodomain protein (mouse Cdx-2) to an evolutionarily conserved promoter element in the sucrase-isomaltase gene. This protein is a member of the caudal family of homeodomain genes which appear to function in early developmental events in Drosophila melanogaster, during gastrulation in many species, and in intestinal endoderm. Unique for this homeodomain gene family, we show that mouse Cdx-2 binds as a dimer to its regulatory element and that dimerization in vitro is dependent on redox potential. These characteristics of the interaction of Cdx-2 with its regulatory element provide for a number of potential mechanisms for transcriptional regulation. Taken together, these findings suggest that members of the Cdx gene family play a fundamental role both in the establishment of the intestinal phenotype during development and in maintenance of this phenotype via transcriptional activation of differentiated intestinal genes.

Spectral studies of SnO2 nanofibres prepared by electrospinning method.

Tin oxide nanofibres with 100-150 nm diameter has been prepared, for the first time by calcination of poly(vinyl acetate) (PVAc)/SnO2 composite fibres prepared by electrospinning method as precursor. Scanning electron microscopic images revealed cylindrical morphology of the fibres after calcination at 600 degrees C. Both, X-ray diffraction (XRD) and Raman spectral data confirmed the presence of phase pure tetragonal rutile tin oxide after calcination process. Room temperature photoluminescence (PL) spectra of tin oxide nanofibres under excitation at 325 nm wavelength show a strong green emission at 525 nm with a band gap of 2.41 eV. FT-IR spectra confirmed the formation of pure tin oxide after calcination at 600 degrees C and complete removal of PVAc during calcination. UV-vis spectrum of the fibres showed absorption at 315 nm due to the direct electron transfer in tin oxide.

Comparative study of linear and curvilinear ultrasound probes to assess quadriceps rectus femoris muscle mass in healthy subjects and in patients with chronic respiratory disease.

INTRODUCTION: Ultrasound measurements of rectus femoris cross-sectional area (RFCSA) are clinically useful measurements in chronic obstructive pulmonary disease (COPD) and critically ill patients. Technical considerations as to the type of probe used, which affects image resolution, have limited widespread clinical application. We hypothesised that measurement of RFCSA would be similar with linear and curvilinear probes. METHODS: Four studies were performed to compare the use of the curvilinear probe in measuring RFCSA. Study 1 investigated agreement of RFCSA measurements using linear and curvilinear probes in healthy subjects, and in patients with chronic respiratory disease. Study 2 investigated the intra-rater and inter-rater agreement using the curvilinear probe. Study 3 investigated the agreement of RFCSA measured from whole and spliced images using the linear probe. Study 4 investigated the applicability of ultrasound in measuring RFCSA during the acute and recovery phases of an exacerbation of COPD. RESULTS: Study 1 showed demonstrated no difference in the measurement of RFCSA using the curvilinear and linear probes (308±104 mm(2) vs 320±117 mm(2), p=0.80; intraclass correlation coefficient (ICC)>0.97). Study 2 demonstrated high intra-rater and inter-rater reliability of RFCSA measurement with ICC>0.95 for both. Study 3 showed that the spliced image from the linear probe was similar to the whole image RFCSA (308±103.5 vs 263±147 mm(2), p=0.34; ICC>0.98). Study 4 confirmed the clinical acceptability of using the curvilinear probe during an exacerbation of COPD. There were relationships observed between admission RFCSA and body mass index (r=+0.65, p=0.018), and between RFCSA at admission and physical activity levels at 4 weeks post-hospital discharge (r=+0.75, p=0.006). CONCLUSIONS: These studies have demonstrated that clinicians can employ whole and spliced images from the linear probe or use images from the curvilinear probe, to measure RFCSA. This will extend the clinical applicability of ultrasound in the measurement of muscle mass in all patient groups.

The conserved terminal guanosine of a group I intron can help prevent reopening of the ligated exons.

The highly conserved terminal guanosine of the Tetrahymena group I intron was mutated to an adenosine. The intron still excised itself but more slowly than the wild-type. At very low concentrations of GTP only ligated exons were produced, but at high concentrations of GTP unligated exons accumulated and the 3' exon acquired a GTP at its 5' end. A series of experiments suggested that GTP was primarily reopening the ligated exons, rather than directly cleaving the 3' splice site. 5' Truncated forms of the wild-type intron can cleave RNA in trans. Cleavage takes place downstream of sequences similar to the last few bases of the 5' exon. The ligated exons would therefore be a potential substrate. We believe that the intron uses the terminal guanosine to compete with exogenous GTP until the ligated exons have dissociated from their binding site. Other interactions between intron sequences which are known to aid in 3' splice-site recognition may assist in this process.

Phosphodiesterase type IV inhibition. Structure-activity relationships of 1,3-disubstituted pyrrolidines.

The synthesis of 1,3-disubstituted pyrrolidines 2 and their activities as type IV phosphodiesterase (PDE) inhibitors are described. Various groups were appended to the nitrogen of the pyrrolidine nucleus to enable structure-activity relationships to be assessed. Groups which render the pyrrolidine nitrogen of 2 nonbasic yielded potent PDE-IV inhibitors. Analogs of amides, carbamates, and ureas of 2 were synthesized to determine the effects that substitution on these functional groups had on PDE-IV inhibitor potency. The structural requirements for PDE-IV inhibitor potency differed among the three classes. A representative amide, carbamate, and urea (2c,d,h) were shown to be > 50-fold selective for inhibiting PDE-IV versus representative PDEs from families I-III and V. Furthermore, these same three inhibitors demonstrated potent functional activity (IC50 < 1 microM) by inhibiting tumor necrosis factor-alpha (TNF-alpha) release from lipopolysaccharide (LPS)-activated purified human peripheral blood monocytes and mouse peritoneal macrophages. These compounds were also tested orally in LPS-injected mice and demonstrated dose-dependent inhibition of serum TNF-alpha levels.

Optimization of 3-(1H-indazol-3-ylmethyl)-1,5-benzodiazepines as potent, orally active CCK-A agonists.

We previously described a series of 3-(1H-indazol-3-ylmethyl)-1,5-benzodiazepine CCK-A agonists exemplified by compound 1 (GW 5823), which is the first reported binding selective CCK-A full agonist demonstrating oral efficacy in a rat feeding model. In this report we describe analogs of compound 1 designed to explore changes to the C3 and N1 pharmacophores and their effect on agonist activity and receptor selectivity. Agonist efficacy in this series was affected by stereoelectronic factors within the C3 moiety. Binding affinity for the CCK-A vs CCK-B receptor showed little dependence on the structure of the C3 moiety but was affected by the nature of the second substituent at C3. Structure-activity relationships at the N1-anilidoacetamide "trigger" moiety within the C3 indazole series were also investigated. Both agonist efficacy and binding affinity within this series were modulated by variation of substituents on the N1-anilidoacetamide moiety. Evaluation of several analogs in an vivo mouse gallbladder emptying assay revealed compound 1 to be the most potent and efficacious of all the analogs tested. The pharmacokinetic and pharmacodynamic profile of 1 in rats is also discussed.

Activation of Fos-like immunoreactivity in the medial preoptic area and limbic structures by maternal and social interactions in rats.

The researchers examined the number of cells showing Fos-like immunoreactivity (Fos-lir) in the brains of hormonally primed parturient rat dams immediately following their first behavioral interactions with pups. Groups were exposed to newborn pups (pup), adult conspecifics (social), or a new food (food), or they were left alone in cages (control/isolate) for a 1-hr period. Rats were then killed, and their brains were prepared for immunohistochemical detection of Fos-lir. Rats in the pup group had higher numbers of cells showing. Fos-lir within the medial preoptic area (MPOA) nuclei than did the social, control/isolate, and, marginally, food groups and higher levels of Fos-lir in a number of amygdaloid nuclei (medial and cortical) and in cingulate and somatosensory cortices than did control/isolate or food groups. Fos-lir in amygdala did not differ between pup and social groups. There were also group differences in Fos-labeling in the olfactory bulbs, with the pup group showing the highest densities. These results show elevated expression of Fos-lir in brain structures that were activated during the expression of maternal behavior, including the olfactory structures, amygdala, and MPOA.

Comparison of intestinal phospholipase A/lysophospholipase and sucrase-isomaltase genes suggest a common structure for enterocyte-specific promoters.

Intestinal phospholipase A/lysophospholipase (IPAL) is an intestine-specific brush-border enzyme expressed during development and along the intestinal crypt-villus axis in a pattern similar to another well characterized brush-border enzyme, sucrase-isomaltase (SI). A tissue-specific DNase I hypersensitive site was identified in chromatin from intestinal nuclei immediately upstream from the transcriptional start site of the IPAL gene. Footprinting analysis showed that two DNA elements within the IPAL promoter were protected by intestinal nuclear proteins. The IPAL-FP1 element was shown to be a monomer binding site for Cdx1 and Cdx2, intestine-specific homeobox proteins. Moreover, this site was important for transcriptional activation of the promoter in intestinal cell lines via interaction with Cdx proteins. Nuclear proteins from both liver and intestine interacted with the IPAL-FP2 element, forming a complex consistent with binding to HNF1. Cdx and HNF1 binding sites have also been shown to be the two major regulatory elements responsible for transcriptional activation of the SI gene promoter, which directs intestine-specific transcription in transgenic mice. These findings suggest that enterocyte genes that are expressed in similar developmental patterns may be regulated by the interaction of common DNA elements and their associated transcription factors.

Noradrenergic involvement in the consolidation of maternal experience in postpartum rats.

If postpartum rats are separated from pups following cesarean delivery, their maternal responsiveness declines such that in tests on day 10 they show maternal onset latencies that do not differ from those shown by virgin rats. If, however, dams are permitted a 1-h experience with pups within 36 h of cesarean delivery, rats exhibit a high level of responsiveness to foster pups on day 10 after c-section. The present research investigates the effect of the noradrenergic system in the long-term consolidation of a brief maternal experience in new mother rats. Groups of dams were cesarean delivered and were either given pups for a brief period 36 h after section (experienced) or received no experience (inexperienced). Immediately following the experience phase, dams were injected with different concentrations of the beta-adrenergic antagonist, propranolol (0, 0.5, 1.0, 5.0 mg/kg), or the adrenergic agonist, isoproterenol (0, 0.25 or 0.5 mg/kg). Ten days after cesarean delivery rats were given maternal induction tests. Rats receiving 60 min of experience and injected with propranolol exhibited significantly longer maternal onset latencies than did saline-injected rats, although their latencies were not as long as shown by the maternally inexperienced groups. In contrast, rats receiving 15 min of experience and injected with isoproterenol exhibited significantly shorter onset latencies than did saline-injected rats, whether or not they exhibited maternal behavior during the initial 15 min exposure period. These results suggest that the noradrenergic system is involved in the consolidation of a maternal experience.

Events and subjective well-being: only recent events matter.

The effect of life events on subjective well-being (SWB) was explored in a 2-year longitudinal study of 115 participants. It was found that only life events during the previous 3 months influenced life satisfaction and positive and negative affect. Although recent life events influenced SWB even when personality at Time 1 was controlled, distal life events did not correlate with SWB. SWB and life events both showed a substantial degree of temporal stability. It was also found that good and bad life events tend to covary, both between individuals and across periods of the lives of individuals. Also, when events of the opposite valence were controlled, events correlated more strongly with SWB. The counterintuitive finding that good and bad events co-occur suggests an exciting avenue for explorations of the structure of life events.

Situational influences on gender differences in agency and communion.

Gender differences were examined in the context of situational effects. Participants monitored interpersonal behavior for 20 days, using an event-sampling strategy. The monitored behaviors reflected dominance and submissiveness (components of agency) and agreeableness and quarrelsomeness (components of communion). The situations reflected differences in the status of work roles: interactions with boss, co-worker, and supervisee. Status influenced agency. Individuals were most agentic when with a supervisee and least agentic when with a boss. Gender did not influence agency but did influence communal behaviors. Women were more communal regardless of social role status; women were especially communal with other women, compared with men with men. Findings about agency supported a social role theory interpretation of gender differences. Results for communion were consistent with accounts of the influence of sex segregation on interpersonal relationships.

Discriminant validity of well-being measures.

The convergent and discriminant validities of well-being concepts were examined using multitrait-multimethod matrix analyses (D. T. Campbell & D. W. Fiske, 1959) on 3 sets of data. In Study 1, participants completed measures of life satisfaction, positive affect, negative affect, self-esteem, and optimism on 2 occasions 4 weeks apart and also obtained 3 informant ratings. In Study 2, participants completed each of the 5 measures on 2 occasions 2 years apart and collected informant reports at Time 2. In Study 3, participants completed 2 different scales for each of the 5 constructs. Analyses showed that (a) life satisfaction is discriminable from positive and negative affect, (b) positive affect is discriminable from negative affect, (c) life satisfaction is discriminable from optimism and self-esteem, and (d) optimism is separable from trait measures of negative affect.

Cross-cultural evidence for the fundamental features of extraversion.

Psychologists have not determined the defining characteristics of extraversion. In four studies, the authors tested the hypothesis that extraversion facets are linked by reward sensitivity. According to this hypothesis, only facets that reflect reward sensitivity should load on a higher order extraversion factor. This model was tested against a model in which sociability links the facets. The authors also tested the generalizability of the model in a diverse sample of participants from 39 nations, and they tested the model using widely used extraversion scales. Results of all studies indicate that only facets that reflect reward sensitivity load on a higher order extraversion factor and that this factor correlates strongly with pleasant affect. Although sociability is undoubtedly an important part of extraversion, these results suggest that extraverts' sociability may be a by-product of reward sensitivity, rather than the core feature of the trait.

Splenectomy abrogates the induction of oral tolerance in experimental autoimmune uveoretinitis.

Oral administration of uveitogenic antigens inhibits the development of experimental autoimmune uveoretinitis (EAU) and the cellular immune response initiated by these antigens. The mechanism of oral tolerance is not completely clear, but accumulating data indicate that suppressor cells are actively involved in this process. The spleen is known to harbor suppressor cells and their precursors and the present study was aimed at testing the role of this organ in the induction of oral tolerance by S-antigen (S-AG). We report here that: (a) splenectomy abrogated the induction of oral tolerance; unlike in sham operated controls, feeding with S-Ag did not inhibit the development of EAU in splenectomized rats; (b) splenectomized rats responded with higher cellular immune responses than did sham operated controls, but feeding with S-Ag inhibited these responses in both groups of animals; (c) splenectomy also abrogated the adoptive transfer of tolerance: EAU induction was inhibited in sham operated recipients of splenocytes from S-Ag fed donors but not in the splenectomized recipients. The data thus indicate that the spleen plays an important role in the induction of oral tolerance, perhaps by acting as the site for induction and/or amplification of cells with suppressor activity.