bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spatial receptive field properties of lateral geniculate cells in the owl monkey (Aotus azarae) at different contrasts: a comparative study
Authors: Kilavik B. E. , Silveira L. C. L. , Kremers J. 
Published: August 2007

AbstractSeveral physiological properties of owl monkey lateral geniculate nucleus (LGN) cells were studied to verify whether its nocturnal habit has an influence on the organization of its subcortical visual system. Receptive field (RF) dimensions were measured using drifting gratings and bipartite field stimuli. We found that owl monkey cells LGN have larger RFs and were on average more non‐linear than those of diurnal monkeys. But, as in other anthropoids, there is an increase in RF centre size with increasing eccentricity, and there is a limited correlation between these centre sizes and retinal ganglion cell dendritic tree sizes. The influence of contrast on sizes and peak sensitivities of RF centres and surrounds and on the response phases was studied. Both the sizes and peak sensitivities of the RF centres and surrounds decrease as contrast increases. As a result, the responses to low spatial frequency stimuli saturate with increasing contrast. Estimates of contrasts at half‐maximal responses confirm the presence of saturation. It was found that the magnocellular cells saturate more strongly than parvocellular cells. The response phase increases with increasing contrast. These data resemble those obtained in the common marmoset, indicating that these are basic features of the primate visual system. We conclude that during evolution and as an adaptation to a nocturnal lifestyle, cells in the owl monkey LGN display an increased spatial integration in comparison with diurnal primate species, without a change in the basic organization common to the primate subcortical visual system.
Spatio‐temporal prediction and inference by V1 neurons
Authors: Guo Kun , Robertson Robert G. , Pulgarin Maribel , Nevado Angel , Panzeri Stefano , Thiele Alexander , Young Malcolm P. 
Published: August 2007

AbstractIn normal vision, visual scenes are predictable, as they are both spatially and temporally redundant. Evidence suggests that the visual system may use the spatio‐temporal regularities of the external world, available in the retinal signal, to extract information from the visual environment and better reconstruct current and future stimuli. We studied this by recording neuronal responses of primary visual cortex (area V1) in anaesthetized and paralysed macaques during the presentation of dynamic sequences of bars, in which spatio‐temporal regularities and local information were independently manipulated. Most V1 neurons were significantly modulated by events prior to and distant from stimulation of their classical receptive fields (CRFs); many were more strongly tuned to prior and distant events than they were to CRFs bars; and several showed tuning to prior information without any CRF stimulation. Hence, V1 neurons do not simply analyse local contours, but impute local features to the visual world, on the basis of prior knowledge of a visual world in which useful information can be distributed widely in space and time.
PI3K/akt, JAK/STAT and MEK/ERK pathway inhibition protects retinal ganglion cells via different mechanisms after optic nerve injury
Authors: Luo Jian‐Min , Cen Ling‐Ping , Zhang Xin‐Mei , Chiang Sylvia Wai‐yee , Huang Yao , Lin Dusheng , Fan You‐Ming , Van Rooijen Nico , Lam Dennis Shun Chiu , Pang Chi Pui , Cui Qi 
Published: August 2007

AbstractRecently we unexpectedly found that PI3K/akt, JAK/STAT and MEK/ERK pathway inhibitors enhanced retinal ganglion cell (RGC) survival after optic nerve (ON) axotomy in adult rat, a phenomenon contradictory to conventional belief that these pathways are pro‐survival. In this study we showed that: (i) the RGC protection was pathway inhibition‐dependent; (ii) inhibition of PI3K/akt and JAK/STAT, but not MEK/ERK, activated macrophages in the eye, (iii) macrophage removal from the eye using clodronate liposomes significantly impeded PI3K/akt and JAK/STAT inhibition‐induced RGC survival and axon regeneration whereas it only slightly affected MEK/ERK inhibition‐dependent protection; (iv) in the absence of recruited macrophages in the eye, inhibition of PI3K/akt or JAK/STAT did not influence RGC survival; and (v) strong PI3K/akt, JAK/STAT and MEK/ERK pathway activities were located in RGCs but not macrophages after ON injury. In retinal explants, in which supply of blood‐derived macrophages is absent, MEK/ERK inhibition promoted RGC survival whereas PI3K/akt or JAK/STAT inhibition had no effect on RGC viability. However, MEK/ERK inhibition exerted opposite effects on the viability of purified adult RGCs at different concentrations in vitro, suggesting that this pathway may be bifunctional depending on the level of pathway activity. Our data thus demonstrate that inhibition of the PI3K/akt or JAK/STAT pathway activated macrophages to facilitate RGC protection after ON injury whereas the two pathways per se did not modulate RGC viability under the injury conditions (in the absence of the pathway activators). In contrast, the MEK/ERK pathway inhibition protected RGCs via macrophage‐independent mechanism(s).
Requirement of the tumour suppressor APC for the clustering of PSD‐95 and AMPA receptors in hippocampal neurons
Authors: Shimomura Atsushi , Ohkuma Mahito , Iizuka‐Kogo Akiko , Kohu Kazuyoshi , Nomura Ryuji , Miyachi Ei‐ichi , Akiyama Tetsu , Senda Takao 
Published: August 2007

AbstractMutations in the adenomatous polyposis coli (APC) gene are associated with familial adenomatous polyposis and sporadic colorectal tumours. The APC gene is expressed ubiquitously in various tissues, especially throughout the large intestine and central nervous system (CNS). In the CNS, the expression of the APC protein is highest during embryonic and early postnatal development. APC associates through its C‐terminal region with postsynaptic density (PSD)‐95, a neuronal protein that participates in synapse development. Here, we examined the involvement of APC in synaptogenesis. In cultured hippocampal neurons, both overexpression of a dominant‐negative construct that disrupts the APC–PSD‐95 interaction and knockdown of APC expression using small interfering RNA (siRNA) inhibited the clustering of PSD‐95 and a glutamate receptor subunit, and reduced alpha‐amino‐3‐hydroxy‐5‐methyl‐isoxazole‐4‐propionate (AMPA)‐induced activity of AMPA receptors; however, the clustering of an N‐methyl‐d‐aspartate (NMDA) receptor subunit was unaffected. These results are suggestive of APC involvement in the development of glutamatergic synapses.
The mental retardation gene CC2D1A/Freud‐1 encodes a long isoform that binds conserved DNA elements to repress gene transcription
Authors: Rogaeva Anastasia , Albert Paul R. 
Published: August 2007

AbstractThe CC2D1A/Freud‐1 gene has recently been linked to non‐syndromic mental retardation and a short isoform of mouse Five prime REpressor Under Dual repression binding protein 1 (Freud‐1) can repress the serotonin‐1A (5‐HT1A) receptor gene in rodent cells. In this study, we addressed the expression, localization and regulation of the human 5‐HT1A receptor gene by a long isoform of human Freud‐1 protein (Freud‐1L). We show that human CC2D1A/Freud‐1 RNA is expressed in brain and peripheral tissues and encodes short and long isoforms, which differ by an upstream in‐frame translational start site. Whereas previous studies identified the short isoform of Freud‐1 as the predominant isoform in rodent cells, we demonstrate that the long isoform is more abundant in human cells, especially in the nuclear fraction. The nuclear localization of Freud‐1L was enriched upon inhibition of chromosome region maintenance 1/exportin 1‐dependent nuclear export, indicating a dynamic regulation of Freud‐1 nuclear localization. Consistent with a functional role in the nucleus, human Freud‐1L bound specifically to its dual repressor element in the 5‐HT1A receptor gene in vitro and repressed transcription from these sites. Importantly, chromatin immunoprecipitation using antibodies specific for human Freud‐1L demonstrated that it is bound to the dual repressor element in chromatin, indicating a functional role in regulating the basal expression of the 5‐HT1A receptor gene. Taken together, these results indicate that both the short and long isoforms of Freud‐1 are expressed, although Freud‐1L is the major isoform that regulates the human 5‐HT1A receptor gene. Disruption of transcriptional regulation by mutation of Freud‐1 may play a role in abnormal brain function leading to mental retardation.
Suppression of vibrotactile discrimination by transcranial magnetic stimulation of primary somatosensory cortex
Authors: Morley J. W. , Vickery R. M. , Stuart M. , Turman A. B. 
Published: August 2007

AbstractA number of human and animal studies have reported a differential representation of the frequency of vibrotactile stimuli in the somatosensory cortices: neurons in the primary somatosensory cortex (SI) are predominantly responsive to lower frequencies of tactile vibration, and those in the secondary somatosensory cortex (SII) are predominantly responsive to higher frequencies. We employed transcranial magnetic stimulation (TMS) over SI in human subjects to investigate the extent to which the inactivation of SI disrupted the discrimination of vibrotactile stimulation at frequencies that give rise to the tactile sensations of flutter (30 Hz) and vibration (200 Hz). Frequency discrimination around the 30‐Hz standard following application of TMS to SI was reduced in seven of the eight subjects, and around the 200‐Hz standard was reduced in all eight subjects. The average change in discrimination following TMS was about 20% for both low and high frequencies of vibrotactile stimulation. These data suggest that disruption of SI: (1) has a direct effect on the discrimination of both low and high frequencies of vibrotactile stimuli, consistent with a serial model of processing, or (2) has a direct effect on low‐frequency vibrotactile stimuli and an indirect effect on the processing of high‐frequency vibrotactile stimuli by SII via cortico‐cortical connections between the two regions.
Activation of afferents to the ventral tegmental area in response to acute amphetamine: a double‐labelling study
Authors: Colussi‐Mas Joyce , Geisler Stefanie , Zimmer Luc , Zahm Daniel S. , Bérod Anne 
Published: August 2007

AbstractThe ventral tegmental area (VTA), primary source of the mesocorticolimbic dopaminergic system, is regarded as a critical site for initiation of behavioural sensitization to psychostimulants. The present study was undertaken to identify the neural pathways converging on the VTA that are potentially implicated in this process. Rats were sensitized by a single exposure to amphetamine (5 mg/kg, s.c.). The distribution of VTA‐projecting neurons activated by amphetamine was examined by combining retrograde transport of the cholera toxin β subunit (CTb), injected into the VTA, with immunodetection of Fos. The quantitative analysis of CTb–Fos double labelling demonstrates that amphetamine induced a rapid activation of Fos in a large number of brain areas projecting to the VTA. More than half of the CTb–Fos double‐labelled neurons were located in the prefrontal cortex, lateral preoptic area–lateral hypothalamus, pontomesencephalic tegmentum, dorsal raphe nucleus, ventral pallidum and nucleus accumbens. In addition, scattered CTb–Fos double‐labelled cells were observed in many other VTA afferent structures, such as claustrum, lateral septum, diagonal band–magnocellular preoptic nucleus, deep mesencephalic nucleus, oral part of pontine reticular nucleus and dorsomedial tegmental area. This suggests that systemic amphetamine activates a wide population of neurons projecting to the VTA that may be important for the modulation of neurobehavioural plasticity produced by this psychostimulant.
Conservative management resulting in complete resolution of a double intussusception in an adult haemophiliac
Authors: Howard J. M. , Hanly A. M. , Stephens R. B. 
Published: August 2007

AbstractAcute abdominal pain in haemophiliacs should be approached as haemorrhage until proven otherwise. With advancements in factor repletion and coagulopathic management a conservative approach should be considered. We describe a case of double colo‐colonic intussusception lead by an intramural haematoma occurring spontaneously and resolving with conservative management in a young haemophiliac. This demonstrates that intussusception in these cases may be transient, and does not require surgical intervention.
Investigation to predict faecal continence in patients undergoing reversal of a defunctioning stoma (Porridge enema test)
Authors: Parés D. , Duncan J. , Dudding T. , Phillips R. K. S. , Norton C. 
Published: August 2007

AbstractObjective  A defunctioning stoma is often performed in cases of major anorectal surgery or sphincter injury. This study aimed to assess the Porridge enema (PE) test as a tool to evaluate function prior to stoma closure.Method  Thirty‐eight patients underwent PE test at a median of 12.5 months after stoma formation prior to consideration of stoma closure. Outcome was assessed by immediate leakage after PE test on lying, standing, walking and the ability to hold the enema for 30 min. Patients available for follow‐up were divided into two groups: group 1 (n = 20) patients with stoma closure performed and group 2 (n = 10) patients where the stoma remains. Eight patients were excluded from analysis as the stoma had not been reversed for reasons unrelated to continence. The results of other investigations performed in these patients were analysed. Finally, we studied the agreement in the interpretation of the test by two investigators blinded to the patient's group and each other's interpretation and to functional results after the stoma was reversed.Results  Anorectal physiology testing and imaging assessment of the anal sphincters was not statistically different between the two groups. There was a significant difference in the percentage of patients in each group that had enema leakage in: lying position (P = 0.002), standing position (P = 0.013), walking (P = 0.002) and ability to defer for 30 min (P = 0.005). There was a good correlation in the interpretation of PE test results by two investigators. Among patients whose stoma was closed and who were evaluated functionally, 55% were fully continent.Conclusion  This report suggests that the PE test is a promising tool as part of evaluation of anorectal function prior to stoma reversal.
Oral ciprofloxacin or trimethoprim reduces bacteriuria after flexible cystoscopy
Authors: Johnson Mark I. , Merrilees David , Robson Wendy A. , Lennon Teresea , Masters John , Orr Kathy E. , Matthews John N.S. , Neal David E. 
Published: August 2007

OBJECTIVETo report a large prospective, pragmatic, double‐blind randomized controlled trial to determine whether oral prophylactic antibiotics reduce the risk of bacteriuria after flexible cystoscopy (FC), as up to 10% of patients develop urinary infection afterwards, with significant morbidity and costs for health services.PATIENTS AND METHODSIn all, 2481 patients were recruited into a three‐arm placebo controlled trial and 2083 completed it. Patients were randomly assigned to one of three treatments; (i) placebo; (ii) one oral dose of trimethoprim (200 mg); or (iii) one oral dose of ciprofloxacin (500 mg), each administered 1 h before a FC under local anaesthetic. A mid‐stream urine specimen was taken before and 5 days after FC; significant bacteriuria was defined as a pure growth of >105 colony‐forming units/mL.RESULTSThe rate of bacteriuria after FC was reduced from 9% in the placebo group to 5% and 3% in patients receiving trimethoprim and ciprofloxacin prophylaxis, respectively. When rates of bacteriuria before FC were considered the odds of developing bacteriuria after FC relative to baseline were 5, 2 and 0.5 for placebo, trimethoprim and ciprofloxacin, respectively.CONCLUSIONThis large trial shows clearly that one dose of oral ciprofloxacin significantly reduces bacteriuria after FC.
Outcome after cytoreductive nephrectomy for metastatic renal cell carcinoma is predicted by fractional percentage of tumour volume removed
Authors: Pierorazio Phillip M. , McKiernan James M. , McCann Tara R. , Mohile Supriya , Petrylak Daniel , Benson Mitchell C. 
Published: August 2007

OBJECTIVETo determine if the fractional percentage of tumour volume (FPTV) removed at cytoreductive nephrectomy predicts disease‐specific survival (DSS), as metastatic renal cell carcinoma ((M+)RCC) is associated with poor overall survival with only a 10–20% patient survival at 2 years.PATIENTS AND METHODSThe Columbia Urologic Oncology Database was reviewed; 1016 patients had renal surgery from 1988 to 2005, 78 patients with (M+)RCC underwent nephrectomy. The FPTV removed was determined using pathological and imaging reports. The patients were stratified as having a > or <90% FPTV. Kaplan–Meier analysis with log‐rank test was used to determine survival advantage between groups. A Cox proportional hazard model was used for FPTV in both univariate and multivariate analyses. Secondary analyses were conducted to determine if the size of the primary tumour or volume of metastases affected outcome and if the FPTV affected hospitalization time.RESULTSIn all, 55 patients had their FPTV calculated exactly; 45 had a >90% FPTV. The median DSS times were 11.6 and 2.9 months for patients with >90% and <90% FPTV removed (P = 0.002). The hazard ratio for death was 0.24 for patients with a >90% FPTV in a univariate model (P = 0.016) and 0.29 in multivariate analysis (P = 0.02). Patients with a <90% FPTV spent a greater percentage of time hospitalized before death, 21.2% vs 6.5% (P = 0.03).CONCLUSIONFor patients with (M+)RCC, overall survival is limited, but can be extended by cytoreductive nephrectomy. The FPTV expected to be removed is a simple and available method to counsel patients regarding the benefits of surgical intervention.
Improving the prognosis of patients after radical cystectomy. Part I: the role of lymph node dissection
Authors: Suttmann Henrik , Kamradt Jörn , Lehmann Jan , Stöckle Michael 
Published: August 2007

The first two reviews are from the same unit in Germany and describe the well‐known but still much discussed ways of improving the prognosis of patients undergoing cystectomy for bladder cancer. The authors review the roles of lymph node dissection and perioperative chemotherapy, and draw conclusions which will be of help for patients having this form of therapy.In a further review, authors from Egypt debate the requirement for a refluxing or non‐refluxing uretero‐ileal anastomosis in low‐pressure reservoirs, drawing on their extensive experience in this field.The optimum treatment for patients with muscle‐invasive bladder cancer remains a matter of intense debate; some authors still question the role of radical cystectomy (RC) per se, as it can be a potentially mutilating procedure with subsequent impairment in quality of life. However, the impairment has not been investigated using validated quality‐of‐life studies. By contrast, it is commonly accepted that no alternative treatment yields similar long‐term survival data to RC. However, survival rates after RC are far from satisfying, particularly for patients with ≥ pT3 and/or pN+ disease. Therefore, various strategies were introduced to improve survival in these patients, i.e. extension of lymph node dissection during radical surgery and perioperative chemotherapy. Both strategies are analysed and discussed in two mini‐reviews, based on data from current publications and from theoretical considerations.
Partitioning phylogenetic and adaptive components of the geographical body‐size pattern of New World birds
Authors: Ramirez Lizabeth , Diniz‐Filho José Alexandre Felizola , Hawkins Bradford A. 
Published: August 2007

ABSTRACTAim To evaluate seasonal body‐size patterns for New World birds in geographical space, to develop environmental models to explain the gradients, and to estimate phylogenetic and adaptive contributions.Location The Western Hemisphere.Methods We used range maps to generate gridded geometric mean body masses. Summer and winter patterns were distinguished based on breeding and non‐breeding ranges. We first generated the geographical gradients, followed by phylogenetic eigenvector regression to generate body sizes predicted by the birds’ positions in a phylogenetic tree, which were used to generate the expected phylogenetic gradient. Subtracting the expected pattern from the observed pattern isolated the adaptive component. Ordinary least squares multiple‐regression models examined factors influencing the phylogenetic, adaptive and combined components of the seasonal body‐size patterns, and non‐spatial and spatial models were compared.Results Birds are larger in the temperate zones than in the tropics. The gradient is quantitatively stronger in winter than in summer. Regression models explained 66.6% of the variance in summer mass and 45.9% of the variance in winter mass. In summer, phylogenetic and adaptive responses of birds contribute equally to the gradient. In winter, the gradient in North America is much stronger than that expected by taxonomic turnover, and responses of species independent of their family membership drive the overall pattern.Main conclusions We confirm Bergmann's rule in New World birds and conclude that winter temperatures ultimately drive the pattern, exerting selection pressures on birds that overwhelm patterns expected by phylogenetic inertia at the family level. However, in summer, the movement of migratory species into the temperate zone weakens the gradient and generates a pattern more congruent with that expected from the taxonomic composition of the fauna. The analytical method we develop here represents a useful tool for partitioning the phylogenetic and non‐phylogenetic components of spatially explicit macroecological data.