bluuebunny/crossref_metadata_2025_split huggingface dataset:
Viral hepatitis among male amphetamine‐inhaling abusers
Authors: Lai S.‐W. , Chang W.‐L. , Peng C.‐Y. , Liao K.‐F. 
Published: April 2007

AbstractBackground: Few studies have focused on the clandestinely consumed amphetamine as a primary drug. The purpose of this study was to estimate the prevalence of hepatitis B virus (HBV) and hepatitis C virus (HCV) infection and the related factors in male amphetamine‐inhaling abusers.Methods: This was a cross‐sectional study. From November 2004 to February 2005, 285 amphetamine‐inhaling male subjects at one prison in Taiwan and 285 age‐matched healthy men without history of using illicit drugs or tattooing were enrolled. A face‐to‐face interview focusing on amphetamine‐addicted history and sociodemographic information was used. Hepatitis B surface antigen (HBsAg) and anti‐HCV were tested.Results: The mean age of the subjects was 34.1 ± 8.6 years (range 17–75 years). Among 285 subjects, 13.3% were positive for HBsAg, 20.0% positive for anti‐HCV and 2.5% positive for combined HBsAg and anti‐HCV. Multivariate logistic regression analysis showed that tattoo (odds ratio (OR) 2.97, 95% confidence interval (CI) 1.37–6.43) and elevated alanine aminotransferase (ALT) (OR 3.15, 95% CI 1.49–6.66) were independently related to persons being anti‐HCV positive. Elevated ALT was related to persons being HBsAg positive (OR 2.60, 95% CI 1.15–5.89).Conclusion: Screening of HBV and HCV infection among amphetamine‐inhaling abusers remains necessary. Tattoo and elevated ALT are identified as the related factors for being anti‐HCV positive. Elevated ALT is the related factor for being HBsAg positive.
Lateral hypothalamic ‘command neurons’ with axonal projections to regions involved in both feeding and thermogenesis
Authors: Oldfield B. J. , Allen A. M. , Davern P. , Giles M. E. , Owens N. C. 
Published: April 2007

AbstractThe concept of ‘command neurons’, whereby single neurons mediate complex and complementary motor functions to generate a stereotyped behaviour, is well developed in invertebrate physiology. The term has also been adopted more recently to explain the neural basis of ‘fight or flight’. In this study we have investigated the possibility that single lateral hypothalamic neurons have the necessary neuroanatomical connections to coordinate two complementary limbs of body weight control, feeding and thermogenesis, thereby acting as ‘command neurons’. The transynaptic retrograde transport of pseudorabies virus (Bartha) from a thermogenic endpoint in the brown adipose tissue of rats has been used in conjunction with other neuronal tracers, introduced into putative CNS feeding centres, to assess the potential for the involvement of command neurons in coordinating these processes. In discrete regions of the lateral hypothalamus, neurons have been identified which have the necessary complement of orexigenic peptides and collateral branching axons to both putative feeding sites and thermogenic sites in brown fat to qualify as candidate central command neurons controlling body weight.
cAMP mediates ammonia‐induced programmed cell death in the microglial cell line BV‐2
Authors: Svoboda Nina , Zierler Susanna , Kerschbaum Hubert H. 
Published: April 2007

AbstractAlthough ammonia is a well‐known neuropathogenic factor, the cellular mechanisms of ammonia toxicity are less characterized. Up to now, the main focus of ammonia toxicity has been on astrocytes and neurons. Despite the significance of microglia in neurodegenerative diseases, little is known about their responsiveness to ammonia. In the present study, we found that ammonia triggered mitosis at concentrations between 30 μm and 3.0 mm but apoptosis at concentrations ≥ 1.0 mm in the murine microglial cell line BV‐2. Most apoptotic cells showed an accumulation of condensed chromatin at the nuclear envelope, blebbing of the plasma membrane, formation of apoptotic bodies and an increase in caspase 3/7 activity. Blockade of caspase 3/7 activity by Ac‐DEVD‐CHO suppressed ammonia‐induced apoptosis. Surprisingly, some BV‐2 cells exposed to ammonia displayed clear signs of mitotic catastrophe, a type of cell death occurring during mitosis. In a further series of experiments, we found that cyclic adenosine 3′,5′‐monophosphate (cAMP) mediated the apoptogenic effects of ammonia, because (i) ammonia dose‐dependently elevated the intracellular cAMP level, (ii) blockade of the adenylyl cyclase by SQ‐22536 suppressed ammonia‐induced apoptosis, (iii) inhibition of phosphodiesterases (PDEs) by the nonselective PDE inhibitor IBMX, or by the PDE4‐selective inhibitor rolipram, increased the relative number of apoptotic cells, and (iv) the cAMP analogues 8‐bromoadenosine cAMP and Sp‐cAMP mimicked the effect of ammonia and triggered apoptosis. Taken together, our results indicate that distinct concentrations of ammonia trigger opposite signalling pathways in microglial cells.
Paradoxical opsin expressing cells in the inner retina that are augmented following retinal degeneration
Authors: Semo Ma'ayan , Vugler Anthony A. , Jeffery Glen 
Published: April 2007

AbstractHere we reveal a population of cells that express cone photoreceptor opsins that are located in the inner retina, distant from outer retinal photoreceptors. These cells are present in rodents and human. They also express a range of key proteins critical in the cone phototransduction cascade and make contact with other retinal neurons. Their opsins are not generally confined to cellular specialized regions but are present throughout the plasma membrane, although their nuclear configurations are similar to those of outer retinal cones. This population is distinct from the ganglion cells that contain melanopsin and which are known to be inner retinal irradiance detectors regulating circadian behaviour. Surprisingly, the size of the population of short wavelength opsin positive cells in the ganglion cell layer is plastic. In normal animals their number declines with age. However, their numbers increase significantly in response to outer retinal photoreceptor loss, probably by drawing on a pool of inner retinal cells that express cone specific markers, but not opsins.
Neurotoxic lesions of ventrolateral prefrontal cortex impair object‐in‐place scene memory
Authors: Wilson Charles R. E. , Gaffan David , Mitchell Anna S. , Baxter Mark G. 
Published: April 2007

AbstractDisconnection of the frontal lobe from the inferotemporal cortex produces deficits in a number of cognitive tasks that require the application of memory‐dependent rules to visual stimuli. The specific regions of frontal cortex that interact with the temporal lobe in performance of these tasks remain undefined. One capacity that is impaired by frontal–temporal disconnection is rapid learning of new object‐in‐place scene problems, in which visual discriminations between two small typographic characters are learned in the context of different visually complex scenes. In the present study, we examined whether neurotoxic lesions of ventrolateral prefrontal cortex in one hemisphere, combined with ablation of inferior temporal cortex in the contralateral hemisphere, would impair learning of new object‐in‐place scene problems. Male macaque monkeys learned 10 or 20 new object‐in‐place problems in each daily test session. Unilateral neurotoxic lesions of ventrolateral prefrontal cortex produced by multiple injections of a mixture of ibotenate andN‐methyl‐d‐aspartate did not affect performance. However, when disconnection from inferotemporal cortex was completed by ablating this region contralateral to the neurotoxic prefrontal lesion, new learning was substantially impaired. Sham disconnection (injecting saline instead of neurotoxin contralateral to the inferotemporal lesion) did not affect performance. These findings support two conclusions: first, that the ventrolateral prefrontal cortex is a critical area within the frontal lobe for scene memory; and second, the effects of ablations of prefrontal cortex can be confidently attributed to the loss of cell bodies within the prefrontal cortex rather than to interruption of fibres of passage through the lesioned area.
Transplantation of conditionally immortal auditory neuroblasts to the auditory nerve
Authors: Sekiya Tetsuji , Holley Matthew C. , Kojima Ken , Matsumoto Masahiro , Helyer Richard , Ito Juichi 
Published: April 2007

AbstractCell transplantation is a realistic potential therapy for replacement of auditory sensory neurons and could benefit patients with cochlear implants or acoustic neuropathies. The procedure involves many experimental variables, including the nature and conditioning of donor cells, surgical technique and degree of degeneration in the host tissue. It is essential to control these variables in order to develop cell transplantation techniques effectively. We have characterized a conditionally immortal, mouse cell line suitable for transplantation to the auditory nerve. Structural and physiological markers defined the cells as early auditory neuroblasts that lacked neuronal, voltage‐gated sodium or calcium currents and had an undifferentiated morphology. When transplanted into the auditory nerves of rats in vivo, the cells migrated peripherally and centrally and aggregated to form coherent, ectopic ‘ganglia’. After 7 days they expressed β3‐tubulin and adopted a similar morphology to native spiral ganglion neurons. They also developed bipolar projections aligned with the host nerves. There was no evidence for uncontrolled proliferation in vivo and cells survived for at least 63 days. If cells were transplanted with the appropriate surgical technique then the auditory brainstem responses were preserved. We have shown that immortal cell lines can potentially be used in the mammalian ear, that it is possible to differentiate significant numbers of cells within the auditory nerve tract and that surgery and cell injection can be achieved with no damage to the cochlea and with minimal degradation of the auditory brainstem response.
Topographic distribution of output neurons in cerebellar nuclei and cortex to somatotopic map of primary motor cortex
Authors: Lu Xiaofeng , Miyachi Shigehiro , Ito Yumi , Nambu Atsushi , Takada Masahiko 
Published: April 2007

AbstractTo investigate the somatotopic organization of the cerebellum, we analysed multisynaptic inputs to the primary motor cortex (MI) using retrograde transneuronal transport of rabies virus. At 3 days after rabies injections into proximal forelimb, distal forelimb and hindlimb representations of the macaque MI, second‐order neurons via the thalamus were labeled in the deep cerebellar nuclei, including the dentate (DN), anterior interpositus (AIN) and posterior interpositus nuclei. In the DN, the labeling of both the forelimb and hindlimb was seen mainly in the dorsal aspect. The labeling of the hindlimb was located rostral to that of the forelimb and the labeling of the proximal forelimb was located slightly rostral to that of the distal forelimb. The same rostrocaudal arrangement was observed in the AIN. In the posterior interpositus nucleus, however, labeling from the MI hindlimb and forelimb representations largely overlapped. At the 4‐day postinjection period, third‐order labeling occurred in Purkinje cells of the cerebellar hemisphere. The Purkinje cell labeling from the forelimb representation, including the proximal and distal regions, was observed primarily in lobules IV–VI and crus I. The proximal forelimb labeling was both rostral and lateral to that of the distal forelimb within lobules IV–VI. However, the hindlimb labeling was seen both rostral and lateral to that of the proximal forelimb within lobules III–VI. These results indicate that the hindlimb, proximal forelimb and distal forelimb are arranged rostrocaudally in the DN and AIN, whereas there is dual somatotopy along the rostrocaudal and lateromedial axes in the cerebellar cortex.
Lesions of rat infralimbic cortex enhance renewal of extinguished appetitive Pavlovian responding
Authors: Rhodes S. E. V. , Killcross A. S. 
Published: April 2007

AbstractIt is well established that extinction is highly context dependent, and several behavioural phenomena associated with the expression of extinction (spontaneous recovery, reinstatement and renewal) have been described as resulting from this context dependency. It has previously been shown that lesions of the infralimbic (IL) region of the medial prefrontal cortex result in increased levels of spontaneous recovery and reinstatement of an extinguished appetitive Pavlovian conditioned response. The current study shows that lesions of the IL cortex also result in increased renewal of a conditioned response when tested in the acquisition context. Thirteen IL‐lesioned and 14 sham‐lesioned rats were trained on an appetitive Pavlovian task in one context (Context A) followed by extinction in a different context (Context B); animals were then tested for renewal of responding in both Context A and B. Both groups demonstrated similarly low levels of responding when tested in the extinction context (B), and greater responding (i.e. renewal) when tested in the acquisition context (A). Further, the level of response renewal was greater in IL‐lesioned animals. The results are discussed in relation to the possible role of the IL cortex in contextual control of extinction.
Constant light housing during nursing causes human DSPS (delayed sleep phase syndrome) behaviour in Clock‐mutant mice
Authors: Wakatsuki Yukako , Kudo Takashi , Shibata Shigenobu 
Published: April 2007

AbstractDelayed sleep phase syndrome (DSPS) is very often seen among patients with sleep‐wake rhythm disorders. Humans with the 3111C allele of the human Clock gene tend to demonstrate a higher evening preference on the morningness–eveningness (ME) preference test. DSPS is thought to be an extreme form of this evening preference. Clock‐mutant mice have been proposed as an animal model of evening preference. In this study, we looked at whether constant light (LL) housing of Clock‐mutant mice during lactation would result in evening preference and/or DSPS. Housed under light–dark (LD) or constant dark (DD) conditions during the lactation period, both wild‐type and Clock‐mutant mice did not show a phase‐delay in the locomotor activity measured under light–dark conditions, whereas constant light housing during lactation significantly caused a delayed onset. The magnitude of the delay during the light–dark cycle was positively associated with free‐running period measured during constant darkness. Among wild, heterozygote, and homozygote pups born from heterozygous dams, only homozygote pups showed a delayed onset. Constant light–housed Clock‐mutant mice exhibited a lower number and delayed peak of phospho‐MAPK‐immunoreactive cells in core regions of the suprachiasmatic nucleus (SCN) compared to light–dark housed wild‐type or Clock‐mutant mice. Activity onset returned to normal with daily melatonin injection at the lights‐off time for 5 days. The present results demonstrate that Clock‐mutant mice exposed to constant light during lactation can function as an animal model of DSPS and can be used to gain an understanding of the ethological aspects of DSPS as well as to find medication for its treatment.
Illusory shape representation in the monkey inferior temporal cortex
Authors: Sáry Gy. , Chadaide Z. , Tompa T. , Köteles K. , Kovács GY. , Benedek G. 
Published: April 2007

AbstractPerceived boundaries without physical differences between shape and background are called illusory contours (ICs). ICs and real contours (RCs) activate the early processing stages of the macaque visual pathway and the occipitotemporal areas of the human visual system in a similar way. However, it is not known how these contours are processed further in the highest visual areas. We tested how the responses of inferior temporal cortical (IT) neurons of macaque monkeys change in relationship to figures with RCs or ICs. The same set of figures [coloured pictures, ICs and silhouettes (SILs)] was presented to awake, fixating rhesus monkeys while the single‐cell activity was recorded in the anterior part of the IT. Most of the neurons responsive to RCs were also responsive to the same shapes presented as ICs. The average net firing rates, however, were significantly lower for the illusory stimuli than for the stimuli in the RC conditions, and the latency of the responses was significantly longer for the ICs than for the RCs. The shape selectivity was found to be different for coloured stimuli and ICs, and similar for SILs and ICs, suggesting the invariance of selectivity to shapes having the same contour but lacking internal surface information. These results suggest different modes of processing of RCs and ICs in the IT, which might explain the differences in their perception.
Emergence of topography in the developing hamster retinocollicular projection: axial differences and the role of cell death
Authors: Upton A. L. , Cordery P. M. , Thompson I. D. 
Published: April 2007

AbstractThe precise ordering of the hamster retinocollicular projection is established over the first two postnatal weeks, coincident with developmental cell death. We have used quantitative retrograde labelling to define topographic precision in the early postnatal projection, to describe its refinement and to assess the contribution played by selective retinal ganglion cell death. The hamster's short gestation period allows the investigation of events occurring prenatally in other rodents. Discrete injections of fluorescent beads in the superior colliculus followed by isodensity contour analysis of labelled retinal cells reveals a dramatic decrease in the extent of retina labelled between postnatal days 2, 6 and 12 (P2, P6, P12): the 20% contour encloses 38.3%, 8.3% and 1.8% of the retina at these ages. Paired injections of two different tracers at variable rostrocaudal (R–C) separations at P2 produced complete overlap of label even when injections were separated by over 1 mm. This was not true for paired mediolateral injections at P2 that were separated by more than 500 µm. Analysis of the segregation of the two tracers (‘nearest‐neighbour analysis’) shows topography improving with age so that by P12 injections separated rostrocaudally by more than 500 µm produced no overlap in the retina. To examine the contribution of selective ganglion cell death to topographic refinement, animals given paired R–C injections at P2 were allowed to survive until P12. Nearest‐neighbour analysis reveals significantly more order in the P2–P12 retinae than after overnight survival. Thus, selective cell death plays a small but appreciable role in correction of topographical errors.
The innervation of parvalbumin‐containing interneurons by VIP‐immunopositive interneurons in the primary somatosensory cortex of the adult rat
Authors: Dávid Csaba , Schleicher Axel , Zuschratter Werner , Staiger Jochen F. 
Published: April 2007

Abstractγ‐Aminobutyric acid (GABA)ergic interneurons of neocortex consist of many subgroups with extremely heterogeneous morphological, physiological and molecular properties. To explore the putative effect of the vasoactive intestinal polypeptide‐immunopositive (VIP +) neurons on neocortical circuitry, the number and distribution of VIP + boutons were analysed on somatodendritic domains of 272 parvalbumin immunopositive (PV +) 3D‐reconstructed neurons. The synaptic nature of 91% of somatic and 76% of dendritic contacts was verified by electron microscopy. The target PV + neurons were separated in two significantly different groups by means of cluster analysis. The first group (Cluster 1, 26%) received on average five times more VIP + synapses than those of the second group. The second group (Cluster 2, 74%) contained cells that were poorly innervated by VIP + boutons or did not have either somatic or dendritic or any VIP innervation at all. The cells of Cluster 1 had a soma size and total dendritic length significantly smaller than that of Cluster 2, however, they received three times more dendritic synapses, which resulted in a five times higher VIP + synaptic density on dendrites. Our results showed that although most of the PV + cells are innervated by VIP + boutons at a varying degree, some 6% of PV + cells received no input from VIP + interneurons. This suggests a refined morphological basis to influence the majority of the PV + interneurons, which are very effectively controlling pyramidal cell firing. Together with metabolic and neuromodulatory effects of VIP, this would probably result in an enhanced responsiveness of the latter cell type to tactile stimuli.
Glycogen synthase kinase 3 activation is essential for the snake phospholipase A2 neurotoxin‐induced secretion in chromaffin cells
Authors: Giner Daniel , López Inmaculada , Ñeco Patricia , Rossetto Ornella , Montecucco Cesare , Gutiérrez Luis M. 
Published: April 2007

AbstractNeuroendocrine chromaffin cells were used to study the mechanism of the snake phospholipase A2 (PLA2) neurotoxin enhancement of exocytosis. Notexin, β‐bungarotoxin, taipoxin or textilotoxin enhanced the fast release of catecholamines elicited by flash photolysis of cytosolic caged calcium. Such an increase correlates with the capacity of these neurotoxins to cause fragmentation of the F‐actin cortical barrier with subsequent accumulation of vesicles in the proximity of the plasma membrane. These PLA2 neurotoxins do not act via protein kinase C activation, which is known to promote F‐actin fragmentation. Lithium, RO31‐8220 and SB216763, three inhibitors of the glycogen synthase kinase 3, prevent both the alteration of the F‐actin peripheral cortex and the enhancement of fast release elicited by these neurotoxins. In addition, glycogen synthase kinase 3 has been detected by immunolocalization in a membranous compartment of the chromaffin cell endoplasmic reticulum (ER). These results suggest that the activation of this enzyme plays a major role in the enhancement of exocytosis of the readily releasable granules caused by PLA2 neurotoxins in neuroendocrine chromaffin cells.
Locomotor exercise alters expression of pro‐brain‐derived neurotrophic factor, brain‐derived neurotrophic factor and its receptor TrkB in the spinal cord of adult rats
Authors: Macias Matylda , Dwornik Anna , Ziemlinska Ewelina , Fehr Susanna , Schachner Melitta , Czarkowska‐Bauch Julita , Skup Malgorzata 
Published: April 2007

AbstractPrevious evidence indicates that locomotor exercise is a powerful means of increasing brain‐derived neurotrophic factor (BDNF) and its signal transduction receptor TrkB mRNA levels, immunolabeling intensity and number of BDNF‐ and TrkB‐immunopositive cells in the spinal cord of adult rats but the contribution of specific cell types to changes resulting from long‐term activity is unknown. As changes in BDNF protein distribution due to systemic stimuli may reflect either itsin‐situsynthesis or its translocation from other sources, we investigated where BDNF and TrkB mRNA are expressed in the spinal lumbar segments. We report on the cell types defined by size, BDNF mRNA levels and number of cells with TrkB transcripts in sedentary and exercised animals following 28 days of treadmill walking. In the majority of cells, exercise increased perikaryonal levels of BDNF mRNA but did not affect TrkB transcript levels. Bidirectional changes in a number of TrkB mRNA‐expressing cells occurred in small groups of ventral horn neurons. An increase in BDNF transcripts was translated into changes in pro‐BDNF and BDNF levels. A 7‐day walking regimen increased BDNF protein levels similarly to 28‐day treadmill walking. Our observations indicate that long‐ and short‐term locomotor activity of moderate intensity produce stimuli sufficient to recruit a majority of spinal cells to increased BDNF synthesis, suggesting that continuous tuning of pro‐BDNF and BDNF levels permits spinal networks to undergo trophic modulation not requiring changes in TrkB mRNA supply.