bluuebunny/crossref_metadata_2025 huggingface dataset:
Spatial models of political competition with endogenous political parties
Authors: Laver Michael , Schilperoord Michel
Published: April 2007

Two important human action selection processes are the choice by citizens of parties to support in elections and the choice by party leaders of policy ‘packages’ offered to citizens in order to attract this support. Having reviewed approaches analysing these choices and the reasons for doing this using the methodology of agent-based modelling, we extend a recent agent-based model of party competition to treat the number and identity of political parties as an output of, rather than an input to, the process of party competition. Party birth is modelled as an endogenous change of agent type from citizen to party leader, which requires describing citizen dissatisfaction with the history of the system. Endogenous birth and death of parties transforms into a dynamic system even in an environment where all agents have otherwise non-responsive adaptive rules. A key parameter is the survival threshold, with lower thresholds leaving citizens on average less dissatisfied. Paradoxically, the adaptive rule most successful for party leaders in winning votes makes citizens on average less happy than under other policy-selection rules.
Reconsolidation of declarative memory in humans
Authors: Forcato Cecilia , Burgos Valeria L. , Argibay Pablo F. , Molina Victor A. , Pedreira María E. , Maldonado Hector
Published: April 2007

The reconsolidation hypothesis states that a consolidated memory could again become unstable and susceptible to facilitation or impairment for a discrete period of time after a reminder presentation. The phenomenon has been demonstrated in very diverse species and types of memory, including the human procedural memory of a motor skill task but not the human declarative one. Here we provide evidence for both consolidation and reconsolidation in a paired-associate learning (i.e., learning an association between a cue syllable and the respective response syllable). Subjects were given two training sessions with a 24-h interval on distinct verbal material, and afterward, they received at testing two successive retrievals corresponding to the first and second learning, respectively. Two main results are noted. First, the first acquired memory was impaired when a reminder was presented 5 min before the second training (reconsolidation), and also when the second training was given 5 min instead of 24 h after the first one (consolidation). Second, the first retrieval proved to influence negatively on the later one (the retrieval-induced forgetting [RIF] effect), and we used the absence of this RIF effect as a very indicator of the target memory impairment. We consider the demonstration of reconsolidation in human declarative memory as backing the universality of this phenomenon and having potential clinical relevance. On the other hand, we discuss the possibility of using the human declarative memory as a model to address several key topics of the reconsolidation hypothesis.
Effect of water temperature and size of females on the timing of spawning of perch Perca fluviatilis L. in Lake Geneva from 1984 to 2003
Authors: Gillet C. , Dubois J. P.
Published: April 2007

The effects of water temperature on the timing of spawning of perch Perca fluviatilis in Lake Geneva were assessed in a 20 year survey (1984–2003). Spawning started at the end of April or at the beginning of May, when the water temperature rose to >10° C, but most of the spawns were laid when water temperature exceeded 12° C. This led to a positive correlation between the date of the mid‐spawning period and the date when the water temperature rose to >12° C. Large perch had a tendency to spawn later than the small ones, which led to a positive correlation between the date of mid‐spawning period and the yearly mean width of perch egg‐ribbons. The coefficient of multiple determination between the date of mid‐spawning period and the mean width of the ribbon of spawn, combined with the date when the water temperature rose to >12° C was r2= 0·77. The perch generally chose deeper spawning places (12 m) at the end of the spawning period than at the beginning (4 m), which was related to water temperature.
Relationship between eyed‐egg percentage and levels of cortisol and thyroid hormone in masu salmon Oncorhynchus masou
Authors: Mingist M. , Kitani T. , Koide N. , Ueda H.
Published: April 2007

A possible cause of the low eyed‐egg percentage that afflicts pond‐reared masu salmon Oncorhynchus masou at a fish hatchery (Kumaishi Fish Hatchery, Hokkaido, Japan) was investigated. Serum cortisol levels of masu salmon during the spawning period were compared between individuals from Kumaishi and those from another station (Mori). Cortisol, thyroxine (T4) and triiodothyronine (T3) hormones were also measured in eyed eggs and their levels were compared to the eyed‐egg percentage. Serum cortisol levels were significantly higher at Kumaishi than at Mori in May and July of the breeding season. At the Kumaishi station, there was a linear positive relationship between serum cortisol and fertilized‐egg cortisol levels of female masu salmon. As cortisol levels in both ovulating females and eyed eggs increased, the eyed‐egg percentage decreased, indicating a highly significant negative relationship between cortisol levels and eyed‐egg percentage. In contrast, as T3 and T4 levels in eyed eggs increased, the eyed‐egg percentage increased. The strong positive correlation between high cortisol levels in serum and in eyed eggs at Kumaishi indicates that the frequently higher cortisol levels may have caused the lowering of the eyed‐egg percentage.
Innate predator recognition and fright response in related populations ofOncorhynchus mykissunder different predation pressure
Authors: Scheurer J. A. , Berejikian B. A. , Thrower F. P. , Ammann E. R. , Flagg T. A.
Published: April 2007

Innate predator recognition and fright response behaviours were compared in a laboratory study between second generation offspring from two related populations of steelhead troutOncorhynchus mykissfrom Sashin Creek, Alaska. The stream population was anadromous and co‐occurred with Dolly VardenSalvelinus malma, a piscivore and salmonid predator. Sashin Lake, formerly fishless, was stocked with fish from the stream population in 1926 and that population has been isolated from heterospecific piscine predation ever since. Fish from the lake population were predicted to show diminished innate fright response to Dolly Varden scent relative to the stream population. The behaviour of 60 individual juvenileO. mykissfrom each population was measured and observed in aquaria before and after exposure to chemical cues of Dolly Varden, conspecific skin extract, or a control of distilled water. The alarm substances caused significant behavioural changes in both populations in the amount of time spent motionless, time spent in the lower water column and feeding frequency. No significant differences were observed between the stream and lake populations in the change in behaviour between pre‐ and post‐stimulus observation periods for any of the measured fright responses, indicating that the sequestered lake population has not lost the ability to detect or respond to conspecific alarm substances or Dolly Varden scent.
Life‐history traits of the endangered river blennySalaria fluviatilis(Asso) and their implications for conservation
Authors: Vinyoles D. , De Sostoa A.
Published: April 2007

The life‐history characteristics of the river blennySalaria fluviatilisin a Mediterranean stream in north‐east Spain have been studied. The maximum age observed was 4+ years in both sexes, although only age groups 0+ and 1+ years were well represented. For both sexes, growth was rapid between April and June (before the summer drought) and in October. The instantaneous rate of monthly growth (April to October) was positively correlated with water depth. All fish attained sexual maturity during their first year of life. Females spawned multiple times. Spawning occurred mainly from June to August, although older females (2+ years old) began in May. The relationship between fecundity and total length recorded for older females in the spring was not significantly different from that obtained for 1 year‐old females in the summer. The mean diameter of ripe oocytes, however, was greater in older females. Larger eggs that were laid during a period of good food supply (spring) might have a higher probability of survival. The results suggest that female fecundity is affected by environmental conditions. The species is characterized by fast growth, early maturity, multiple spawning and limited longevity. This may be a good life‐history strategy for small fish species in unstable environments, where adult mortality is high, variable or unpredictable. Some life‐history traits of the river blenny suggest that this species might be vulnerable to more severe drought conditions than those associated with the Mediterranean climate.
First U.K. recording in the wild of the bighead carp Hypophthalmichthys nobilis
Authors: Britton J. R. , Davies G. D.
Published: April 2007

Five specimens of bighead carp Hypophthalmichthys nobilis were captured from a lake in eastern England in January 2006, their first confirmed recording in the wild in the U.K. They varied in fork lengths from 746 to 796 mm and mass from 10·0 to 13·5 kg. All the fish were age 9 years and were slow growing compared to populations elsewhere in their expanded range.
Can ultraviolet radiation influence cod Gadus morhua L. year class strength: a model study
Authors: Eilertsen H. C. , Wyatt T. , Hansen E.
Published: April 2007

To simulate the UVR dose that eggs and larvae of cod Gadus morhua receive during spring in Lofoten, the main spawning area of north‐east Arctic cod, a model driven by wind, tides and surface heat flux was applied. The model was forced using in situ measured hydrographical data while underwater UVR doses were calculated using satellite data, ozone measurements, meteorological data and in situ diffuse extinction coefficients. The model was run with data from 1934 to the present and indicated that UVR induced mortality has little effect on cod year class strength. When thin ozone layers and slack winds coincide with meagre phytoplankton stocks, UVR induced mortality may be harmful to eggs and larvae. As these events are highly episodic, and since the spawning period of cod is long (c. 3 months), they are believed to have only a minor influence on the overall survival of cod eggs and larvae.
Scale morphology of greater lizardfish Saurida tumbil (Bloch, 1795) (Pisces: Synodontidae)
Authors: Jawad L. A. , Al‐Jufaili S. M.
Published: April 2007

A comparative study comprising scale morphology and squamation of Saurida tumbil was conducted to identify the most useful scale and squamation characters within the different body regions and length groups and to clarify their significance for future systematic studies. The presence of the caudal pores is documented for the first time in teleosts. In addition, the presence of crenae and spines formed by posterior orientation and projection of circuli is recorded for the first time in a member of the Synodontidae. Scales of S. tumbil show some characters that are either never seen or they are exceedingly rare in scales of other teleosts. These are: two types of scalar denticles, denticles in the inter‐circular area, and twin or Siamese scales. Several other scale characters have shown a consistent variation in different body regions and in fishes from different length groups. These are: focus position; bilobate rostral field edge; presence of three radii; long, narrow and separated crenae; papillae‐form, crowded scalar denticles with posterior directed spines; the number of scale rows between anterior end of the dorsal fin and the lateral line.
Prey selection and efficiency of naïve and experienced juvenile sockeye salmon
Authors: Massee K. C. , Kim J. , Berejikian B. A. , Hardy R. W.
Published: April 2007

Prey selection and growth efficiency of juvenile sockeye salmon Oncorhynchus nerka switched between live prey and pelleted diets were investigated. First feeding sockeye salmon fry were placed into one of three dietary treatments for 7 months prior to assessing potential differences with a growth and a behavioural assay. Dietary treatments were (1) adult Artemia franciscana for 1 month, followed by pelleted feed for an additional 6 months (Art− BD), (2) pelleted feed from first feeding for 7 months (BD) and (3) adult A. franciscana for 1 month, and a combination of pelleted feed and live adult A. franciscana for 6 months (Art+ BD). Equal numbers from each treatment group were then tagged, pooled into replicate ‘common garden’ tanks and fed novel live prey items (Daphnia sp. and mosquito Culex pipiens larvae) for an additional 3 weeks. No significant differences in the growth efficiency of sockeye salmon were found during the 3 week feeding trial on the novel prey items. Additional sockeye salmon from each dietary treatment were used in a behavioural assay to determine if the treatments had an impact on foraging efficiency (prey selection or time to capture prey). No significant differences in prey selection were found among treatment groups in time to capture pellets, A. franciscana or mosquito larvae. Also, no significant differences were found within treatment groups in time to capture different food sources. No substantive benefits in foraging efficiency of sockeye salmon associated with prior exposure to live prey were demonstrated. This suggests that altering existing hatchery practices for juvenile sockeye salmon by offering live food prior to release is unlikely to influence post‐hatchery feeding behaviour or increase post‐release survival.
Intrabasin variations in age and growth of bullhead: the effects of temperature
Authors: Abdoli A. , Pont D. , Sagnes P.
Published: April 2007

The variability of growth variables and age structure in bullhead Cottus gobio was studied in a single river catchment by comparing populations inhabiting river reaches with different thermal regimes. Age and growth variables were determined by examining 540 sagittal otoliths from specimens ranging between 19 and 146 mm total length. Growth of young bullhead (0+ and 1+ years) was higher in the warmest sites, especially in relation to water temperature during the growing season (spring and summer). Growth of older bullhead (2+ to 5+ years) was negatively related to mean water temperature of the site. The growth performance of bullhead over its whole life cycle was negatively correlated with water temperature, which could be partly explained by a higher energy allocation to reproduction in the warmest sites. Life span was longer in the colder sites (7 years) than in the warmer ones (4 or 5 years), and bullhead matured earlier in the warmer sites (age 1+ or 2+ years) compared to the colder ones (age 2+ or 3+ years). These results, combined with previous data on reproductive traits, suggest the possible effects that global warming could have on bullhead population dynamics.
Bluegill Lepomis macrochirus synchronize pectoral fin motion and opercular pumping
Authors: Tytell E. D. , Alexander J. K.
Published: April 2007

The relative timing between operculum and pectoral fin motion was examined in swimming bluegill Lepomis macrochirus to determine if respiratory fluid flows from the operculum might have an effect on flow over the pectoral fin. Five bluegill were filmed swimming at speeds from 0·5 to 1·5 body (total) lengths s−1. The timing of opercular pumping and pectoral fin beating was noted and analysed using circular statistics. Fish tended to ventilate their gills every second or third pectoral fin beat. While locomotion and ventilation had different frequencies, however, they were synchronized: fish maintained a consistent phase relationship between them. Thus, within pectoral fin beats when the operculum pumps, the jet consistently occurred during pectoral fin abduction, ending just after the fin was fully abducted and beginning adduction. Based on the distance between the opercular slit and the pectoral fin base, the jet was estimated to reach the fin during maximum abduction. Dye flow visualization confirmed this estimate, revealing that the opercular flow wraps around the base of the fin during peak abduction, when it is likely to have little hydrodynamic effect.
A multivitamin supplementation and education intervention as an effective means of increasing multivitamin use among postpartum women of Mexican origin
Authors: O'Rourke Kathleen M. , Roddy Mary E.
Published: April 2007

Postpartum Hispanic women in the USA are at elevated risk for neural tube defects in subsequent pregnancies from the combined effects of ethnicity, folate depletion from the prior pregnancy and lactation, and high parity rates with short inter‐birth intervals. This study evaluated an education programme and distribution of a 3‐month starter package of multivitamins among Hispanic women attending nutrition clinics for low‐income women in El Paso, Texas. At 1–6 weeks postpartum, 329 subjects were selected to receive education only, multivitamins only, education and multivitamins, or no intervention. Multivariable regression obtained odds ratios (OR) and 95% confidence intervals [CI] to measure the association between intervention status and self‐reported multivitamin use at least four times per week at 6 and 12 months postpartum, while controlling for potential confounding variables.

Multivitamin distribution was related to consumption at both 6 months (OR = 3.5 [95% CI 1.1, 11.2]) and 12 months (OR = 6.5 [95% CI 1.5, 28.3]). Multivitamins plus education was most effective in increasing multivitamin use at both periods: 6 months (OR = 4.0 [95% CI 1.53, 11.7]) and 12 months (OR = 6.4 [95% CI 1.7, 24.2]). At enrolment, 66% of women regularly took vitamins, and approximately 35% took them at both 6 and 12 months postpartum. The education intervention alone was not associated with multivitamin use at either 6 months (OR = 0.79 [95% CI 0.3, 2.4]) or 12 months (OR = 3.1 [95% CI 0.8, 12.1]). Multivitamin use declines precipitously during postpartum at the time Hispanic women may be susceptible to a subsequent pregnancy. This study provides evidence that multivitamin starter packs sustain multivitamin usage up to 1 year postpartum for a specific high‐risk group, but the effect of educational intervention alone should be further studied.
Blastomycosis in solid organ transplant recipients
Authors: Gauthier G.M. , Safdar N. , Klein B.S. , Andes D.R.
Published: April 2007

Abstract: Background. Blastomyces dermatitidis, the etiologic agent of blastomycosis, causes severe disease and substantial mortality in those immunocompromised by acquired immunodeficiency syndrome or malignancy. In solid organ transplant recipients, the epidemiology, clinical features, and outcomes have not been fully described.

Methods. We conducted a retrospective case‐series at the University of Wisconsin Hospital and Clinics. Case patients were solid organ transplant recipients with blastomycosis.

Results. From 1986 to 2004, we identified 11 cases of post‐transplant blastomycosis with 64% occurring between 2000 and 2004. Onset of infection occurred a median of 26 months post transplantation with near equal distribution before and after the first year of transplantation. Rejection did not precede any case of post‐transplant blastomycosis. Opportunistic co‐infections were common, occurring in 36% of patients. Pneumonia was the most common clinical presentation and was frequently complicated by acute respiratory distress syndrome (ARDS). Extrapulmonary disease predominantly involved the skin and spared the central nervous system. The overall mortality rate was 36%; however, this increased to 67% in those with ARDS. None of the surviving patients relapsed or received routine secondary antifungal prophylaxis.

Conclusion. Blastomycosis is an uncommon infection following solid organ transplantation that is frequently complicated by ARDS, dissemination, and opportunistic co‐infection. After cure, post‐transplant blastomycosis may not require lifelong antifungal suppression.
Suppression of cell‐mediated immunity by a donor‐transmitted lymphocytic choriomeningitis virus in a kidney transplant recipient
Authors: Gautam Amitabh , Fischer S.A. , Yango A.F. , Gohh R.Y. , Morrissey P.E. , Monaco A.P.
Published: April 2007

Abstract: Infection with lymphocytic choriomeningitis virus (LCMV) in rodents, the primary host, is known to cause suppression of cell‐mediated immunity. Serial determinations using a functional cell‐mediated immune assay in a kidney transplant recipient with donor‐transmitted LCMV also suggested profound suppression of cellular immunity. This suppression persisted in spite of reduction of immunosuppression. With the clearance of the virus there was reconstitution of the cellular immune response.
Development of Kaposi's sarcoma under sirolimus‐based immunosuppression and successful treatment with imiquimod
Authors: Babel N. , Eibl N. , Ulrich C. , Bold G. , Sefrin A. , Hammer M.H. , Rosenberger C. , Reinke P.
Published: April 2007

Abstract: Kaposi's sarcoma (KS) is a vascular neoplasm typically observed in the immunocompromised patient populations, such as acquired immunodeficiency syndrome or transplant patients. KS can appear simultaneously at multiple sites as red to purple, maculo‐papular or nodular cutaneous lesions sometimes showing a visceral extension. Sirolimus, an immunosuppressive agent with potent antitumor activity, has been effective in combating post‐transplant KS. However, an aggressive regimen of immunosuppression for therapy of severe acute rejection episodes may abolish the antitumor effects of sirolimus. The following is a description of KS development under immunosuppressive therapy with sirolimus, and the successful treatment of KS lesions utilizing the topical application of imiquimod 5% cream, an immune response modifier.
Lateral canthal fixation using an oblique vertically orientated asymmetric periosteal transposition flap
Authors: Game Justin , Morlet Nigel
Published: April 2007

Abstract

Herein a modification of the highly useful lateral tarsal strip procedure is presented. The refinement of the technique uses an oblique, vertically orientated, asymmetric, periosteal transposition (OVAPT) flap from the lateral orbital rim to fix the tarsal strip. From a consecutive series of 53 patients, A cohort of 49 procedures on 41 patients with a minimum of 3‐month follow up is described. The procedure had a high rate of success in terms of canthal fixation over the median 14‐month follow up. There was only one case of late stretching of the canthal repair in an anophthalmic orbit, one case of recurrent cicatricial ectropion due to an inadequate skin graft, and finally a case of early recurrent tarsal ectropion. The OVAPT flap further enhances the stability of the tarsal strip procedure, and allows greater control of lid position and tension. The pull is in a superior and lateral direction, mimicking that of the lateral canthal tendon.
Measurement of retinal thickness from three‐dimensional images obtained from C scan images from the optical coherence tomography ophthalmoscope
Authors: Mizota Atsushi , Sakuma Toshiro , Miyauchi Osamu , Honda Miki , Tanaka Minoru
Published: April 2007

Abstract

Background:  One of the unique features of the optical coherence tomography (OCT) ophthalmoscope is that it can record C scan images of the retina. The purpose of this study was to determine the best recording time to measure the retinal thickness with the OCT ophthalmoscope. In addition, the accuracy of the measurements was examined by comparing the values obtained by the OCT ophthalmoscope with those obtained with the Stratus OCT Model 3000 (OCT III) assuming that the OCT III gives an accurate measurement of retinal thickness.

Methods:  The topography mode of the OCT ophthalmoscope was used. First, the average retinal thickness recorded with 2‐s scans was compared with that recorded with 4‐s scans for a recording area of 15° × 15°. Next, the average retinal thickness recorded by the OCT ophthalmoscope was compared with that obtained by the Fast Macular Thickness program of the OCT III in patients with macular oedema.

Results:  The mean retinal thickness of the central area was 208.1 μm for both 2 and 4 s recording times. The average retinal thickness obtained by the OCT ophthalmoscope was highly correlated and not significantly different from the values obtained by the OCT III. The largest differences obtained by the two instruments were seen in the parts of the retina with accumulation of hard exudates.

Conclusions:  Accurate measurements of retinal thickness can be obtained with the OCT ophthalmoscope by 2‐s scans, and thus, the OCT ophthalmoscope can be a valuable instrument for clinical assessments of retinal thickness.
Glaucoma screening: analysis of conventional and telemedicine‐friendly devices
Authors: Kumar Sajeesh , Giubilato Antonio , Morgan William , Jitskaia Ludmila , Barry Chris , Bulsara Max , Constable Ian J , Yogesan Kanagasingam
Published: April 2007

Abstract

Purpose:  Portable, telemedicine‐friendly devices offer novel opportunity for screening and monitoring glaucoma in the remote and rural regions of the world. This study examines the effective combination of telemedicine‐friendly screening devices for detection of glaucoma in relation with conventional, hospital‐based devices.

Methods:  A total of 399 eyes were screened with telemedicine‐friendly devices and conventional, hospital‐based devices such as ophthalmoscope, tonometer and perimeter.

Results:  Combination of age and family history of glaucoma alone has a sensitivity of 35.6% (specificity 94.2%, area under the curve 0.81, correctly classified 81.1%) and an addition of telemedicine‐friendly or conventional visual field tests optimized the sensitivity to 91.1% (specificity 93.6%, area under the curve 0.95, correctly classified 93%). Analysis indicates good agreement between vertical cup‐to‐disc ratio by ophthalmoscopy and digital image reading. An addition of intraocular pressure test does not change sensitivity (35.6%) and specificity (94.2%).

Conclusion:  This study indicates that evaluations of cup‐to‐disc ratio and visual field, using telemedicine‐friendly devices, are most useful tools in screening for glaucoma. When used together these devices may be an alternative for conventional glaucoma screenings.
Disseminated mucormycosis and orbital ischaemia in combination immunosuppression with a tumour necrosis factor alpha inhibitor
Authors: Singh Pritpal , Taylor Simon F , Murali Rajmohan , Gomes Lavier J , Kanthan Gowri L , Maloof Anthony J
Published: April 2007

Abstract

Disseminated mucormycosis, with pulmonary and cerebral angioinvasive disease, developed in a 65‐year‐old woman with rheumatoid arthritis being treated with combination immunosuppression including adalimumab. Clinical presentation included progressive orbital ischaemia. To the best of the authors' knowledge, this is the first reported case of disseminated mucormycosis in a patient treated with a tumour necrosis factor inhibitor. Important pathophysiological factors are considered.
In vivo microscopy of Best's Vitelliform Macular Dystrophy: optical coherence tomography study of combined stage III and IV lesions
Authors: Arora Ritu , Das Sima , Shroff Daraius , Narula Ritesh , Chauhan Deepender
Published: April 2007

Abstract

A 35‐year‐old man presented with decreased vision in both eyes. Fundus biomicroscopy of the right eye revealed a pseudohypopyon along with an area of hyperpigmentation and scarring at the macula (combined stage III and IVb Best's Vitelliform Macular Dystrophy [BVMD]). The left eye showed the presence of a pseudohypopyon along with macular atrophy (combined stage III and IVa). On optical coherence tomography both eyes had a neurosensory retinal detachment with an optically clear subretinal zone, an accumulation of material between neurosensory retina and the retinal pigment epithelium corresponding to the pseudohypopyon and subfoveal photoreceptor atrophy. We document on optical coherence tomography the transition of BVMD from stage III to IV (in the form of the combined stage). These new findings may be considered unique for this stage of BVMD, and would help in a further understanding of the disease as it passes through its various stages.
Scleral perforation after trans‐scleral cyclodiode laser for intraocular pressure reduction
Authors: Amariotakis George , Ressiniotis Thomas , Voros Gerasimos M , Birch Michael
Published: April 2007

Abstract

Herein a case is reported of a full‐thickness scleral burn in the left eye of a 61‐year‐old man, following contact trans‐scleral cyclodiode laser treatment for traumatic aphakic glaucoma, unresponsive to maximal medical treatment. The defect was successfully repaired by scleral suturing under local anaesthetic.
Culture‐proven Aspergillus fumigatus infection in a primary hydroxyapatite orbital implant
Authors: Sharma Neil S , Ooi Ju‐Lee , Maloof Tiba C , Wilcsek Geoffrey , Francis Ian C , Coroneo Minas T
Published: April 2007

Abstract

Hydroxyapatite orbital implants are widely used in enucleation surgery. Infection in this setting is an uncommon but severe complication. Herein a patient with a 3‐year history of chronic socket discharge, orbital discomfort, conjunctival breakdown and implant exposure after enucleation and implantation of a hydroxyapatite sphere 7 years previously is reported. Repeated attempts at covering the exposed implant failed. Eventually the implant was removed, and Aspergillus fumigatus was cultured from the explanted material. This is the second reported case of Aspergillus infection of a hydroxyapatite orbital implant, and the first case where fungal cultures were positive.
Motor activity is modulated via different neuronal circuits in rats with chronic liver failure than in normal rats
Authors: Cauli Omar , Mlili Nisrin , Llansola Marta , Felipo Vicente
Published: April 2007

The mechanisms by which liver failure alters motor function remain unclear. It has been suggested that liver disease alters the neuronal circuit between basal ganglia and cortex that modulates motor function. Activation of group I metabotropic glutamate receptors in the nucleus accumbens (NAcc) by injecting (S)‐3,5‐dihydroxyphenylglycine (DHPG) activates this circuit and induces locomotion We analysed byin vivobrain microdialysis the function of the circuits that modulate motor function in rats with liver failure due to portacaval shunt (PCS). We inserted cannulae in the NAcc and microdialysis probes in the NAcc, ventral pallidum (VP), substantia nigra pars reticulata (SNr), medio‐dorsal thalamus (MDT), ventro‐medial thalamus (VMT) or prefrontal cortex (PFCx). We injected DHPG in the NAcc and analysed extracellular neurotransmitters concentration in these areas. The results indicate that in control rats DHPG induces locomotion by activating the ‘normal’ neuronal circuit: NAcc → VP → MDT → PFCx. In PCS rats this circuit is not activated. In PCS rats, DHPG injection activates an ‘alternative’ circuit: NAcc → SNr → VMT → PFCx. This circuit is not activated in control rats. DHPG injection increases dopamine in the NAcc of control but not of PCS rats, and glutamate in PCS but not in control rats. DHPG‐induced increase in dopamine would activate the ‘normal’ neuronal circuit, while an increase in glutamate would activate the ‘alternative’ circuit. The identification of the mechanisms responsible for altered motor function and coordination in liver disease would allow designing treatments to improve motor function in patients with hepatic encephalopathy.
Subventricular zone‐derived neuroblast migration to the olfactory bulb is modulated by matrix remodelling
Authors: Bovetti Serena , Bovolin Patrizia , Perroteau Isabelle , Puche Adam C.
Published: April 2007

In the rodent brain neural progenitor cells are born in the subventricular zone and migrate along a pathway called the rostral migratory stream (RMS) into the olfactory bulb where they differentiate into several classes of interneurones. In the adult, tangential migration in the RMS takes place in ‘chains’ of cells contained within glial tubes. In contrast, neonatal neuroblasts along the RMS lack these defined glial tubes and chains, migrating instead as individual cells. Time‐lapse confocal microscopy of neuroblasts at each of these ages shows that individual cells migrate in a saltatory manner with bursts of high speed followed by periods of slower speed. Tangential migration within a glial tube is 20% faster than migration as individual cells. Neuroblasts may also interact and modify the extracellular matrix during migration through expression of a family of proteins, the matrix metalloproteinases (MMPs). MMPs are present and active along the subventricular zone–olfactory bulb pathway. In the presence of inhibitors of MMPs, neuroblast migration rates were reduced only when cells migrate individually. Chain migration in the adult was unaffected by MMP inhibitors. Taken together, these data suggest that MMPs only influence migration as individual cells and not as chains.
Embryonic motor neuron dendrite growth is stunted by inhibition of nitric oxide‐dependent activation of soluble guanylyl cyclase and protein kinase G
Authors: Xiong Guoxiang , Mojsilovic‐Petrovic Jelena , Pérez Cristian A. , Kalb Robert G.
Published: April 2007

We have examined the participation of a neuronal nitric oxide synthase (nNOS) signaling pathway in the elaboration of motor neuron dendrites during embryonic life. During chick embryogenesis, nNOS is expressed by interneurons that surround the motor neuron pools in the ventral horn. Pseudorabies virus tracing suggests that these cells, while juxtaposed to motor neurons are not synaptically connected to them. The downstream effectors, soluble guanylyl cyclase (sGC) and protein kinase G (PKG), are found in motor neurons as well as several other populations of spinal cord cells. To determine the functional significance of the nNOS/sGC/PKG signaling pathway, pharmacological inhibitors were applied to chick embryos and the effects on motor neuron dendrites monitored. Inhibition of nNOS activity led to a lasting reduction in the overall size and degree of branching of the dendritic tree. These alterations in dendritic architecture were also seen when the activity of sGC or PKG was blocked. Our results suggest that normal motor neuron dendrite elaboration depends, in part, on the activity‐dependent generation of NO by ventral horn interneurons, which then activates sGC and PKG in motor neurons.
Enhancement of dopaminergic properties and protection mediated by neuronal activation of Ras in mouse ventral mesencephalic neurones
Authors: Chakrabarty Koushik , Serchov Tsvetan , Mann Stefan A. , Dietzel Irmgard D. , Heumann Rolf
Published: April 2007

The poor differentiation and survival of dopaminergic neurones are practical constraints in their therapeutic applications. Here we explored the role of neuronally activated Ras in ventral mesencephalon‐derived neurospheres generated from synRas mouse embryos. The expression of Val12 Ha‐Ras transgene and enhanced Ras activity was evident after differentiation of the neurospheres with a corresponding activating phosphorylation of mitogen‐activated protein kinase. Phosphorylation of Akt/PKB, the target kinase of phosphoinositide 3‐kinase, along with phosphorylation of Bad and CREB were enhanced in synRas‐derived differentiated neurosphere cultures. Furthermore, increased Nurr1 expression was associated with elevated numbers of dopaminergic neurones in synRas‐derived cultures compared with the wild‐type. Correspondingly, tyrosine hydroxylase promoter assays revealed enhanced transcriptional activation of the promoter in synRas‐derived cultures. synRas‐derived dopaminergic neurones were greatly resistant to degeneration induced by various noxious stimuli. Consistently, the transgenic expression of activated Ras attenuated the adverse 6‐hydroxydopamine effects on dopaminergic neurones. Dopaminergic neurones derived from both wild‐type and synRas cultures expressed voltage‐gated potassium and sodium currents, fired action potentials and exhibited electrical network activity. Thus, expression of the transgene promotes survival and enhances differentiation towards a dopaminergic cell fate without altering their basic electrical properties. Our results suggest that intracellular cell therapy mimicking trophic signalling may offer potential benefit in models of human disease associated with dopamine neurone dysfunction.
Central nervous system and non‐central nervous system antigen vaccines exacerbate neuropathology caused by nerve injury
Authors: Ankeny Daniel P. , Popovich Phillip G.
Published: April 2007

Previously, we showed that autoimmune (central nervous system myelin‐reactive) T cells exacerbate tissue damage and impair neurological recovery after spinal cord injury. Conversely, independent studies have shown T cell‐mediated neuroprotection after spinal cord injury or facial nerve axotomy (FNAx). The antigen specificity of the neuroprotective T cells has not been investigated after FNAx. Here, we compared the neuroprotective capacity of autoimmune and non‐autoimmune lymphocytes after FNAx. Prior to axotomy, C57BL/6 mice were immunized with myelin basic protein, myelin oligodendrocyte glycoprotein (MOG) or ovalbumin (a non‐self antigen) emulsified in complete Freund's adjuvant (CFA). FNAx mice receiving injections of phosphate‐buffered saline (PBS) only (unimmunized) or PBS/CFA emulsions served as controls. At 4 weeks after axotomy, bilateral facial motor neuron counts were obtained throughout the facial motor nucleus using unbiased stereology (optical fractionator). The data show that neuroantigen immunizations and ‘generic’ lymphocyte activation (e.g. PBS/CFA or ovalbumin/CFA immunizations) exacerbated neuron loss above that caused by FNAx alone. We also found that nerve injury potentiated the effector potential of autoimmune lymphocytes. Indeed, prominent forelimb and hindlimb motor deficits were accompanied by disseminated neuroinflammation and demyelination in FNAx mice receiving subencephalitogenic immunization with MOG. FNAx or neuroantigen (MOG or myelin basic protein) immunization alone did not cause these pathological changes. Thus, irrespective of the antigens used to trigger an immune response, neuropathology was enhanced when the immune system was primed in parallel with nerve injury. These data have important implications for therapeutic vaccination in clinical neurotrauma and neurodegeneration.
Behavioural and neural deficits induced by rotenone in the pond snail Lymnaea stagnalis. A possible model for Parkinson's disease in an invertebrate
Authors: Vehovszky Ágnes , Szabó Henriette , Hiripi László , Elliott Christopher J. H. , Hernádi László
Published: April 2007

Parkinson's disease is a neurodegenerative disorder, related to the loss of dopamine (DA)‐containing neurons in the substantia nigra. In experimental animals, both vertebrates and invertebrates, rotenone, a commercially available organic pesticide, induces symptoms of Parkinson's disease. We found that that rotenone is toxic to the pond snail Lymnaea stagnalis (4‐day LC50 0.8 µm). Rotenone, at concentrations from 0.1 to 5 µm, caused progressive and irreversible behavioural deficits in both acute and chronic exposure. Chronic exposure to 0.5 µm rotenone led to a progressive decrease in spontaneous locomotion and in feeding, reaching almost 100% inhibition of both behaviours by the 7th day of rotenone treatment. In the central nervous system preparation made on the 7th day of treatment the postsynaptic potentials evoked by the identified dopaminergic RPeD1 neuron disappeared whereas the synaptic inputs received by the RPeD1 from a peptidergic neuron (VD4) were still functional. Immunostaining revealed that the tyrosine hydroxylase immunoreactivity decreased below the detectable level in both the RPeD1 cell body and its axonal processes. Finally, HPLC assay showed a significant (25%) decrease in DA level in the CNS by the 7th day of rotenone treatment. We conclude that, as in vertebrates, rotenone disrupts feeding and locomotion of the model mollusc Lymnaea stagnalis. One possible target of rotenone is the dopaminergic neurons in the CNS. We therefore suggest that Lymnaea stagnalis is a suitable invertebrate model for the study of Parkinson's disease, allowing direct analysis of the response of dopaminergic systems to rotenone at behavioural, cellular and neuronal levels.
Nigrostriatal lesion induces D2‐modulated phase‐locked activity in the basal ganglia of rats
Authors: Zold Camila L. , Ballion Bérangère , Riquelme Luis A. , Gonon François , Murer M. Gustavo
Published: April 2007

There is a debate as to what modifications of neuronal activity underlie the clinical manifestations of Parkinson's disease and the efficacy of antiparkinsonian pharmacotherapy. Previous studies suggest that release of GABAergic striatopallidal neurons from D2 receptor‐mediated inhibition allows spreading of cortical rhythms to the globus pallidus (GP) in rats with 6‐hydroxydopamine‐induced nigrostriatal lesions. Here this abnormal spreading was thoroughly investigated. In control urethane‐anaesthetized rats most GP neurons were excited during the active part of cortical slow waves (‘direct‐phase’ neurons). Two neuronal populations having opposite phase relationships with cortical and striatal activity coexisted in the GP of 6‐hydroxydopamine‐lesioned rats. ‘Inverse‐phase’ GP units exhibited reduced firing coupled to striatal activation during slow waves, suggesting that this GP oscillation was driven by striatopallidal hyperactivity. Half of the pallidonigral neurons identified by antidromic stimulation exhibited inverse‐phase activity. Therefore, spreading of inverse‐phase oscillations through pallidonigral axons might contribute to the abnormal direct‐phase cortical entrainment of basal ganglia output described previously. Systemic administration of the D2 agonist quinpirole to 6‐hydroxydopamine‐lesioned rats reduced GP inverse‐phase coupling with slow waves, and this effect was reversed by the D2 antagonist eticlopride. Because striatopallidal hyperactivity was only slightly reduced by quinpirole, other mechanisms might have contributed to the effect of quinpirole on GP oscillations. These results suggest that antiparkinsonian efficacy may rely on other actions of D2 agonists on basal ganglia activity. However, abnormal slow rhythms may promote enduring changes in functional connectivity along the striatopallidal axis, contributing to D2 agonist‐resistant clinical signs of parkinsonism.
High pressure modulation of NMDA receptor dependent excitability
Authors: Mor Amir , Grossman Yoram
Published: April 2007

Pressure above 1.1 MPa induces in mammals and humans the high pressure neurological syndrome (HPNS). HPNS is characterized by cognitive and motor decrements associated with sleep disorders, EEG changes, tremor, and convulsions that ultimately may lead to death. Previous theories proposed that augmented response of the glutamatergic N‐methyl‐d‐aspartate receptor (NMDAR) or reduced GABAergic inhibition may be involved. Recently, we have reported that isolated NMDAR response was augmented at high pressure. We now test whether this augmentation induces neuronal hyperexcitability. We studied high pressure effects on pharmacologically isolated NMDAR field excitatory postsynaptic potentials (fEPSPs) and on their efficacy in generating population spikes (PSs). Sprague–Dawley male rats were used. Hippocampal coronal brain slices were prepared, constantly superfused with physiological solutions, gas‐saturated at normobaric pressure, and compressed up to 10.1 MPa with helium. fEPSPs and PSs were recorded from the dendritic and the somatic layers of CA1 pyramidal neurons in response to Schaefer collaterals stimulation with trains of five stimuli at 25 Hz. Pressure caused PSs to appear earlier in the train. However, PS delay, rise time and decay time were increased and PS amplitude, frequency, and number were decreased in the last responses in the train. The decrease in late fEPSPs was associated with a reduction of the total number of PSs in the train, apparently without a change in the synaptic efficacy. These results may partially explain the neuronal hyperexcitability observed at pressure. Therefore, it is postulated that significant hyperexcitability is attained at pressure only when the normal fast fEPSP is intact.
A Selective Review of Recent Developments in the Economic Growth Literature
Authors: Kong Tao
Published: April 2007

The role of institutions in the process of economic growth and development has generated considerable interest among researchers over the past few decades. In particular, incorporating institutional variables into the established growth theories and empirics involves understanding the impact and mechanisms through which institutions affect growth. In surveying recent developments in the economic growth literature, this review pays attention to the resurgent institutionalist research trend and its implications for growth theory and empirical research on growth. Policy issues primarily focused on Asian Pacific developing countries are highlighted.
Financing Health Insurance in Asia Pacific Countries
Authors: Sidorenko Alexandra A. , Butler James R.G.
Published: April 2007

The paper discusses models of health insurance, including compulsory (social) health insurance, voluntary insurance, and community‐based financing schemes. It illustrates the features of these models in terms of coverage, funding, sustainability, payment mechanisms, public–private mix, risk protection, and cost‐containment properties, and outlines some emerging challenges to health financing arrangements. Health financing systems used in Japan, Korea, Taiwan, ASEAN and China are discussed, and implications are drawn for the developing countries in the Asia Pacific contemplating health insurance reform.
Integration of South Asian Economies: an exercise in frustration?
Authors: Das Dilip K.
Published: April 2007

This paper examines the factors underlying the slow progress towards economic integration between the countries of the South Asian region, and discusses the worth and likelihood of an effective agreement. It is argued that substantial integration will only take place after further economic growth leads to increased complementarity in their economic structures.
Glutathione‐S‐transferase T1 and M1 gene polymorphisms in Greek patients with multiple sclerosis: a pilot study
Authors: Stavropoulou C. , Korakaki D. , Rigana H. , Voutsinas G. , Polyzoi M. , Georgakakos V. N. , Manola K. N. , Karageorgiou C. E. , Sambani C.
Published: April 2007

Oxidative stress has been implicated in the pathogenesis of multiple sclerosis (MS). Glutathione‐S‐transferases (GSTs) are detoxification enzymes, evolved to protect cells against reactive oxygen metabolites. Both GSTT1 and GSTM1 genes exhibit a homozygous deletion polymorphism (null genotype) leading to abolished enzyme activity. We studied the impact of the GSTT1 and GSTM1 polymorphisms on MS susceptibility in a case–control study of 47 Greek patients and 165 controls. Correlations between genotype, gender and disability status were also investigated. The incidence of both GSTT1 and GSTM1 genotypes did not differ significantly between controls and patients. A significantly increased frequency of GSTM1 null genotype was found amongst female patients (65.5%) as compared with males (33.3%, P =0.04). The results suggest that GSTT1 and GSTM1 have no major pathogenetic role on the MS occurrence, nor any strong modifying effect on the disability status. The higher incidence of GSTM1 null genotype observed in female patients, suggests a possible role of the GSTM1 detoxification pathway in a gender‐dependent manner.