bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of the export Constraint on Canadian Wheat In 1977/78
Authors: Spriggs John , McKinzie Lance
Published: July 2010

The analysis suggests that Canadian wheat exports in 1977/78 were reduced by an amount between 0.7 and 1.7 million metric tons because of a constraint due to transportation and handling problems. Estimates are made of the effect of this export constraint on domestic utilization, supply and the off‐Board price. Estimates are also made of the effects on these variables of three possible Canadian Wheat Board (CWB) strategies for handling the export constraint. The strategies involve the use of delivery quotas and the initial payment as instruments of the CWB.

L'analyse suggère que les exportations canadienes de blé ont été réduites en 1977/78 d'un montant compris entre 0.7 et 1.7 millions de tonnes. Ces réductions sont dûes a l'effet d'une contrainte posée par des problèmes de transport et de maniement. L'impact de cette contrainte sur les exportations a étéégalement estimé sur la demande domestique, sur I'offre et sur le prix hors‐Commission. Les effets sur ces mêmes variables ont été aussi quantifies en utilisant trois strategies possibles de la Commission Canadienne du Blé (CCB). Ces stratégies invoquent l'utilisation par la CCB de différents niveaux de quotas de livraison et de paiement initial.
The Effect of Energy Price Increases on the U.S. Livestock Sector
Authors: Yanagida John F. , Conway Roger K.
Published: July 2010

This study is unique and crucial to the current time period because of the recent high energy price escalation. The uniqueness of this study pertains to the void in energy impact research of the agricultural sector, more specifically to livestock. The U.S. Department of Energy has models estimating economy‐wide impacts, but not the specific impacts on agriculture. The Iowa State study concentrated on the grain sector.

The results presented here indicate that energy price increases will have substantial effects on livestock prices and production. Energy price increases will also result in differential impacts on livestock commodities (with poultry and eggs having the largest price and production effects). Furthermore, the multi‐period framework enables the livestock model to capture lagged production responses. Noticeable is the higher impacts occurring in the third and fourth years.

In the future, higher energy costs may induce changes in U.S. production, processing and distribution patterns of livestock commodities. The highly vertically integrated poultry and egg industries may begin shifting production locations away from the colder northern regions to areas with more temperate climates. For industries like beef, pork and dairy, there may be increased range production to reduce impacts from higher feed costs. For all industries, closer proximity of processing plants to major livestock producing areas may occur.
A Dynamic Regression Model of the U.S. Hog Market
Authors: Shonkwiler J. Scott , Spreen Thomas H.
Published: July 2010

Historical patterns of hog slaughterings are analyzed and related to a hog‐corn price ratio series using the transfer function or dynamic regression technique. This technique permits explicit tests of causal relationships and provides a systematic means for specifying distributed lag forms. It is determined that the hog‐corn price ratio series leads hog slaughterings and that there is no feedback. The estimated transfer function is analyzed in terms of its implications for the supply of hogs and its implications for the length of the hog cycle.

Nous analyserons les schémas historiques de l'abattage de pores et Us mettrons en correspondence avec une série de rapportsprix du porc —prix du maïs en ulilisant lafonction de transfert ou la technique de regression dynamique. Cette technique permet de tester explicitement les relations causales et foumit un moyen systématique de spécifier les formes de retard distribué. On a determine que Vabattage de pores dépend de la série de rapports prix du pore —prix du maïs mais que I'inverse n'est pas vrai. La fonction de transfert est analysée en fonction de ce qu'elle impliquepour I'approvisionnement en pores et pour la longueur du cycle chez les pores.
Social Costs of Supply‐Restricting Marketing Boards: Reply
Authors: Veeman Michele M.
Published: July 2010

The general thrust of the preceding critical comments by Johnson, Spriggs and Van Kooten is that the costs of the supply‐restricting marketing board programs have been over‐emphasized. It is suggested that there may not even be any social costs of supply restriction, that even the traditional “deadweight triangle” loss of allocative efficiency might be outweighed by increases in consumers' and producers' surplus associated with increased stability from these programs. This proposition is completely at variance with available empirical evidence from these programs.
Decision‐making Criteria for Purchasing Milk Quota at the Individual Farm Level: Reply
Authors: Stonehouse D. Peter , MacGregor Murray A.
Published: July 2010

Careful perusal of the comment by Barichello suggests that there are no substantive criticisms of the issues raised in our original paper. At the same time, it is apparent that there is some misinterpretation of the models that we used, and of the assumptions underlying the models. For example, the optimality criterion that marginal cost equals marginal revenue in the earlier models is important in determining whether profits in the enterprise can be increased or decreased. However, the difference between average total costs and average revenue is important in determining the levels of profits and hence the potential rents involved.
Supply Management in Canadian Agriculture: An Assessment of the Economic Effects
Authors: Schmitz Andrew
Published: July 2010

Marketing boards with supply management powers have become part of Canadian agriculture, yet whether these boards improve society's welfare is a much‐debated issue. This paper reviews both the methodology and the empirical results of studies which have assessed the effects of supply management. All of the studies reviewed show that there is a sizeable income transfer from consumers to producers along with a misallocation of resources as a result of supply management. However, one could easily reverse these conclusions by changing the assumptions upon which past research has rested. Furthermore, additional research is needed on supply management in the context of both a rent‐seeking framework and from an industrial organization point of view.

Les commissions de commercialisation possédant des pouvoirs sur la gestion des stocks. sont devenues inhérentes a ľagriculture canadienne; il y a cependant, controverse quant a ľeffet qu'apportent ces commissions sur le bien‐être de la société. Cette analyse examine à la fois la méthodologie ulilisée, de méme que les résullats empiriques obtenus selon des études examinées, montrent qu'il y a un transfert considérable de revenu, entre les consummateurs et les producteurs, allant de pair avec une mauvaise répartition des ressources, résultant de la gestion des stocks. Cependant, comme le démontre cette étude, il est facilement possible ďinverser ces conclusions en changeant les hypothèses sur lesquelles la recherche antérieure a été bátie. De plus, une recherche supplément aire, sur la gestion des stocks, dans le contexte ďune structure recherchant un cadre, et du point de vue de ľorganisation industrielle est nécéssaire.
The Economic Effects of Intervention in Canadian Agriculture
Authors: Harling Kenneth F. , Thompson Robert L.
Published: July 2010

Interventions affecting producers and consumers of agricultural commodities are a major topic of public debate in Canada at present. The impact of federal interventions affecting eight commodities (wheal, barley, oats, potatoes, beef, pork, poultry and eggs) is examined using concepts of nominal and effective protection. Lessons to be drawn from this analysis are that intervention is much more pervasive than is often realized, and that decisions about altering intervention must be made commodity‐by‐commodity because the economic situation of each is unique.

Les interventions affectant les producteurs el les consommateurs de denrées agricoles. est un sujet majeur de débat public au Canada, en ce moment. Ľimpact des interventions affectionnant huit denreés (le blé, ľorge. ľavoine, les pommes de terre. le hoeuf, le porc, la volaille el les oeufs) est examiné en utilisant des concepts de protection nominate et effective. Les conclusions devant être tirées de cette analyse, sont que ľintervention est beaucoup plus répandue que ľon peul le réaliser. et qu ‘il est conseillé. en ce qui concerne les modifications sur ľintervention. de procéder denrée par denrée. car la situation économique de chacune ďentre elle est unique.
An Economic Assessment of the Significance of Long‐Range Transported Air Pollutants for Agriculture in Eastern Canada
Authors: Forster Bruce A.
Published: July 2010

This paper is based upon a report prepared by the author for Agriculture Canada and Environment Canada. The views expressed in the paper are those of the author. I am indebted to Thomas Crocker for discussions on the subject matter. Comments of the reviewers of this journal proved useful in drafting the present version.

This paper surveys, collates and interprets information from the scientific literature pertaining to the agricultural impacts of long‐range transported air pollutants (acid deposition and ozone) in Eastern Canada in order to provide a preliminary assessment of their economic significance. While most crop scientists believe that Ozone is the major air pollutant causing damage to a number of crops in Eastern Canada, in terms of economic impacts, acid deposition may be considerably more important if the Lee and Neely (1980) corn yield‐loss estimate of 9 percent is correct. Agricultural soils receive a net economic benefit from acid deposition because of the sulphur input which is a fertilizing agent; however, this is small ($2.6 million) compared to the possible direct corn crop damage ($105 million) attributable to acid deposition.
The International Coffee Agreement: Economics of the Nonmember Market
Authors: Bohman Mary , Jarvis Lovell S.
Published: July 2010

The provisions of the 1983 International Coffee Agreement (ICA) and proposed reforms to eliminate exports to nonmember importers at discounted prices are analyzed. The discounted sales were a key issue that led to the breakdown of negotiations for a new ICA and the end of export quotas under the current agreement. A model of the world coffee market incorporating the policy response of exporting countries is used to analyze the welfare implications of the different alternatives. The model shows that the price discounts result from the structure of the current agreement (the existence of nonmember importing countries) and allocation of export quotas for the member market, which does not reflect export capacity. Welfare calculations based on the model show that several small exporters derive substantial benefits from nonmember market sales. These exporters will not be willing to comply with an arrangement to allocate quotas for the nonmember market unless they receive a large share of this market. However, the large exporters appear determined to retain their market share. The results of the model predict that, unless importers no longer insist on eliminating the price discounts, a new agreement is unlikely.
Effects of Initial Payment Policy on the Welfare of Saskatchewan Wheat and Barley Producers
Authors: Clark J. Stephen , Siemens Jonaly K. , Fleming Catherine S.
Published: July 2010

This paper calculates the historical ex ante producer surplus of initial payments acting as price floors to Saskatchewan wheat and barley producers. To do this, a Nerlovian‐type partial adjustment model and rational expectations are used. The Nerlovian model is somewhat unique in that it is argued that the Nerlovian partial adjustment model can be expanded to a multi‐product partial adjustment model, and this is strongly supported by the data. The calculation of the ex ante producer surplus to Saskatchewan producers indicates that initial payment policy is causing only minor market distortions.

Dans le présent document, on établit la partie excédentaire des paiements par anticipation initiaux à la production qui servent de prix plancher aux producteurs de blé et d'orge de la Saskatchewan. Pour cela, on s'est basé sur un modéle à ajustement partiel de type Nerlovian et les attentes rationnelles. Le modèle Nerlovian est particulier en ce sens qu'on suppose que le modèle à ajustement partiel peut s'étendre à de nombreux produits, ce que confirment nettement les données. Le calcul de la part excédentaire du paiement original versé aux producteurs de la Saskatchewan révèle que la politique du paiement initial n'entraîne que de très légères perturbations sur le marché.
Decomposition Measures of Technical Efficiency for Ontario Dairy Farms
Authors: Weersink Alfons , Turvey Calum G. , Godah Abdulahi
Published: July 2010

Technical efficiency measures for Ontario dairy farms are computed and decomposed into purely technical, congestion and scale efficiency measures using a non‐parametric programming approach. Approximately 42% of the farms in the sample are technically efficient, while the major sources of inefficiency for the remaining farms are due to pure technical allocation and to non‐optimal scale of production. A censored regression indicate that herd size, milk yield and butterfat content of milk has a positive influence on efficiency, while negative effects are found from the proportion. of total feed purchased and overcapitalization. The variation in optimal scale between herd sizes implies a range of farm sizes will continue to exist, provided the appropriate technology for the scale of operation is chosen.

Des mesures d'efficacité technique pour des fermes laitières en Ontario sont calculées et ensuite décomposées en mesures de rendement techniques d'échelle et de congestion à l'aide d'une approche de programmation non‐paramétrique. Environ 42% des fermes dans l'échantillon sont techniquement efficaces. Les principales sources d'inefficacité des autres fermes sont reliées à des problèmes d'allocation technique et d'échelle de production. Une régression censurée indique que la grosseur de troupeau, la production de lait par vache de même que le pourcentage de gras dans le lait ont une influence positive sur le rendement tandis que la proportion de fourrage acheté et la sous‐capitalisation ont une influence négative. La variation dans l'échelle optimale de production par grosseur de troupeau laisse sous‐entendre qu'on continuera de voir un certain écart dans la taille des fermes laitiéres si les technologies appropriées pour les differences échelles de production sont selectionnées.
Consumer Demand for Pesticide Free Food Products in Canada: A Probit Analysis
Authors: Magnusson Erik , Cranfield J. A. L.
Published: July 2010

Pesticide Free Production™ (PFP™) is a new crop production strategy that has emerged in the Canadian prairies. Emphasis is placed on substituting human capital for chemical inputs in field crop production. Consumer response to the introduction of food products containing PFP™ inputs is unknown. A consumer survey was developed and implemented to assess what food products consumers would purchase if available in a PFP™ form and what factors affect demand for PFP™ food products. Results from a probit model suggest strong consumer interest in food products containing grains and oilseeds produced in a PFP™ cropping system. Respondents concerned with pesticides in the environment and/or food products, who would switch grocery stores to purchase a PFP™ food product, who were less than 36 years of age, had higher average household income and who would pay a premium for a PFP™ food product were more likely to choose food products with PFP™ ingredients.
Market Advisory Service Recommendations and Wheat Producers' Selling Decisions
Authors: Klumpp Joni M. , Brorsen B. Wade , Anderson Kim B.
Published: July 2010

This study uses actual producer transaction data to determine how Oklahoma wheat producers' selling decisions compare to recommendations from market advisory services and market incentives as reflected in futures spreads. Results show that producers responded to expected returns to storage as measured by futures spreads. Also, Oklahoma producers make marketing decisions that are either unrelated or the opposite of recommendations from market advisory services.

La présente étude a utilisé des données de transactions réelles pour comparer les décisions de vente des producteurs de blé de l'Oklahoma avec les recommandations faites par des services consultatifs et les stimulants du marché tels que reflétés dans les écarts. Les résultats ont montré que les producteurs ont réagi aux rendements attendus de l'entreposage tels que mesurés par les écarts. De plus, les décisions commerciales des producteurs de l'Oklahoma sont soit indépendantes des recommandations des services conseils, soit totalement contraires à ces recommandations.
Predicting the Effect of Land‐Use Policies on Wildlife Habitat Abundance
Authors: Langpap Christian , Wu JunJie
Published: July 2010

Land‐use change is arguably the most pervasive socioeconomic force driving the change and degradation of ecological systems and wildlife habitat. This paper integrates an econometric model of land use with a species‐habitat association matrix to assess the effects of land use policies on land use changes and the resulting impacts on habitat abundance for 763 terrestrial vertebrates in four western states of the United States (California, Oregon, Washington, and Idaho). Results suggest that if the goal is to protect biodiversity through habitat conservation, directly acquiring land and setting it aside for habitat preservation (e.g., by purchasing development rights) is more effective than policies that attempt to change the relative returns from different land uses.

On peut dire que le changement d'affectation des terres constitue la force socioéconomique la plus répandue entraînant la modification et la dégradation des écosystèmes et des habitats fauniques. Dans le présent article, nous avons intégré un modèle économétrique d'affectation des terres et une matrice espèces‐habitats pour évaluer l'impact des politiques d'affectation des terres sur les changements d'affectation des terres et leurs répercussions sur l'abondance des habitats pour 763 vertébrés terrestres dans quatre États de l'Ouest des États‐Unis (Californie, Oregon, Washington et Idaho). Si l'objectif visé est la protection de la biodiversité par la conservation des habitats, les résultats semblent indiquer que l'acquisition directe de terres en vue de les réserver pour la préservation des habitats (en faisant l'acquisition de droits d'aménagement par exemple) est plus efficace que les politiques qui tentent de modifier les rendements relatifs tirés des diverses affectations des terres.
Reproductive biology in King vulturesSarcoramphus papa: at the Paris Menagerie
Authors: SCHLEE MARSHA A.
Published: July 2010

The wild population of the King vultureSurrorumphus pupais declining and little is known about its breeding biology. Data on breeding the species in captivity are also rare and to date there have been no detailed studies made. This paper provides a first description of the most striking features of nest building, incubation, hatching, parental care and the development of young. The study covers seven breeding seasons between 1985 and 1992 during which time one nestling was parent reared in 1989 and another was hand‐reared in 1992.
CERCI©: a computer system for the demographic and genetic analysis of captive invertebrates, fish and other populations of colony animals
Authors: BURLINGHAM‐JOHNSON AJAY , CLARKE DAVE , PEARCE‐KELLY PAUL
Published: July 2010

Existing computer systems for analysing demographic and genetic data have been designed primarily for individually identifiable animals and are largely applicable to the higher vertebrates. The particular difficulties in recording data for invertebrates, fishes, amphibians and reptiles are not easily addressed. CERCI© has been developed, using captive populations of Partula spp snails as subjects, to analyse the quantity and complexity of data which arise from colony species.
Matthew's Gladstone
Authors: SHANNON RICHARD
Published: July 2010

The Gladstone Diaries. Vol. XII. 1887–1891. Edited by H.C.G. Matthew. Oxford: Clarendon Press. 1994. Ixxxvii, 535 pp. ℒ65.00. ISBN 0198204639.

The Gladstone Diaries. Vol. XIII. 1892–1896. Edited by H.C.G. Matthew. Oxford: Clarendon Press. 1994. ix, 486 pp. ℒ65.00. ISBN 0198204647.

The Gladstone Diaries. Vol. XIV. Index. Edited by H.C.G. Matthew. Oxford: Clarendon Press. 1994. xv, 862, pp. ℒ65.00. ISBN 0198204655.

Gladstone, 1875–1898. By H.C.G. Matthew. Oxford: Clarendon Press. 1995. xi, 421 pp. ℒ25.00. ISBN 0198204051.
Stimulus‐Transcription Coupling in Focal Cerebral Ischemia
Authors: Kiessling Marika , Gass Peter
Published: July 2010

Glutamate‐mediated spreading depression is currently thought to be a key event in the pathogenesis of potential neuronal degeneration in the ischemic ‘penumbra’. Glutamate receptor stimulation causes induction of transcription factors that belong to the class of immediate early genes (IEGs), thought to be involved in coupling neuronal excitation to target gene expression. Focal cerebral ischemia elicits a homogeneous expression of several IEGs, prominently in cortex. In the ischemic core, discrepancies are observed between mRIMA and protein levels, due to a severe, persistent protein synthesis deficit, preventing the translation of IEG encoded mRNAs. Outside the ischemic core, widespread IEG expression occurs in the entire ipsilateral cortex at mRNA as well as at protein level. This homogeneous expression of transcription factors can be pinpointed to at least two different pathogenetic mechanisms by means of appropriate pharmacological antagonists. Prolonged IEG induction in the ‘penumbra’, an area in which neurons are metabolically compromised but not yet energy‐depleted, cannot be suppressed by the administration of N‐methyl‐D‐aspartate (NMDA) receptor antagonists. In contrast, short‐lasting IEG induction in undamaged neurons remote from the ischemic territory, though also caused by ischemia‐elicited spreading depression, can be blocked by NMDA receptor antagonists. In both areas, IEG expression identifies neurons destined to survive but is likely to be mediated by different signal transduction pathways, at the receptor, second messenger and/ or the DIMA level.
Functional Recovery after Brain Infarction: Plasticity and Neural Transplantation
Authors: Johansson Barbro B. , Grabowski Martin
Published: July 2010

In the past, little attention has been given to the role of brain plasticity for the long term functional outcome in experimental stroke although there is substantial evidence for plasticity in other experimental models of neurological disorders. Under clinical conditions, functional improvement occurs in most stroke survivors during the initial months after the ischemic incidence. Recent PET studies in stroke patients, investigated two months or later after stroke, indicate a considerable potential for functional plasticity in the adult human cerebral cortex. Research aimed at the identification of the mechanisms underlying functional recovery should be given high priority, particularly with regard to environmental factors and pharmacological interventions.

Pilot experiments of environmental enrichment significantly improved the functional outcome of laboratory animals after brain infarction. Fetal neocortical tissue grafted into the infarcted area in adult rats received afferent fibres from the intact brain and responded to contralateral sensory stimulation with increased metabolic activity, indicating functional integration between neocortical grafts and host afferent systems. However, reciprocal connections from the graft to the host tissue were rare, and it remains to be shown whether grafting will be able to restore the complex cortical organization of the infarcted tissue.
Differential Regulation of Bax, Bcl‐2, and Bcl‐X Proteins in Focal Cortical Ischemia in the Rat
Authors: Isenmann Stefan , Stoll Guido , Schroeter Michael , Krajewski Stanislaw , Reed John C. , Bähr Mathias
Published: July 2010

Focal ischemia in the parietal cortex of the rat results in massive neuronal death in the infarct zone and penumbra between 12 hours and 6 days after photothrombosis. To examine a possible role of Bcl‐2 family proteins in this process of cell death, we investigated their expression by immunoblot assays and immunocytochemistry, and correlated expression patterns with TUNEL as well as morphological signs indicative of apoptosis. In the center of the lesion Bax immunostaining was increased in many degenerating neurons between 4 hours and 3 days after the induction of photothrombosis. At all time points examined, Bcl‐2 and Bcl‐X protein levels were markedly reduced in injured neurons as compared to the unlesioned side. At the border of the ischemic lesion, two areas were distinguished: 1 – 2 days after induction of photothrombosis, pyknotic cells located immediately adjacent to the lesion core displayed nuclear Bcl‐X and Bax immunoreactivity. In contrast, large, morphologically intact neurons located more towards the healthy brain parenchyma displayed an increase in cytoplasmic Bcl‐2 and Bcl‐X proteins. Double staining for each of the Bcl‐2 family proteins and TUNEL revealed that DNA strand breaks and nuclear fragmentation seen in cells located in the lesion core were often associated with increased levels of Bax, but not with elevated Bcl‐2 or Bcl‐X protein levels, suggesting a role for Bax in the induction of apoptotic death in these cells. The upregulation of Bcl‐2 and Bcl‐X expression in surviving neurons close to the penumbra might reflect an active survival mechanism that protects these neurons from cell death following a sublethal insult.
Mouse Models of Human Lysosomal Diseases
Authors: Suzuki Kinuko , Proia Richard L. , Suzuki Kunihiko
Published: July 2010

Genetically authentic animal models of human lysosomal diseases occur spontaneously in many mammalian species. However, most are among larger domestic or farm animals with only two well‐defined genetic lysosomal diseases known among rodents. This status changed dramatically in recent years with the advent of the combined homologous recombination and embryonic stem cell technology, which allows directed generation of mouse models that are genetically equivalent to human diseases. Almost all known human sphingolipidoses, two mucopolysaccharidoses and aspartylglycosamin‐uria have so far been duplicated in mice and more are expected in the near future. This technology also allows generation of mouse mutants that are not known or are highly unlikely to exist in humans, such as “double‐knockouts.” These animal models will play an important role in studies of the pathogenesis and treatment of these disorders. While the utility of these mouse models is obvious, species differences in brain development and metabolic pathways must be always remembered, if the ultimate goal of the study is application to human patients.
Pick's Disease: A Modern Approach
Authors: Dickson Dennis W.
Published: July 2010

Pick's disease is a rare dementing disorder that is sometimes familial. The cardinal features are circumscribed cortical atrophy most often affecting the frontal and temporal poles and argyrophilic, round intraneuronal inclusions (Pick bodies). Clinical manifestations reflect the distribution of cortical degeneration, and personality deterioration and memory deficits are often more severe than visuospatial and apraxic disorders that are common in Alzheimer's disease, but clinical overlap with other non‐Alzheimer degenerative disorders is increasingly recognized. Neuronal loss and degeneration are usually maximal in the limbic system, including hippocampus, entorhinal cortex and amygdala. Numerous Pick bodies are often present in the dentate fascia of the hippocampus. Less specific features include leukoencephalopathy and ballooned cortical neurons (Pick cells). Glial reaction is often pronounced in affected cerebral gray and white matter. Tau‐immunoreactive glial inclusions are a recently recognized finding in Pick's disease, and neuritic changes have also recently been described. Variable involvement of the deep gray matter and the brainstem is typical, with a predilection for the monoaminergic nuclei and nuclei of the pontine base. Neurochemical studies demonstrate deficits in intrinsic cortical neurotransmitter systems (e.g., somatostatin), but inconsistent loss of transmitters in systems projecting to the cortex (e.g., cholinergic neurons of the basal nucleus). Biochemical and immunocytochemical studies have demonstrated that abnormal tau proteins are the major structural components of Pick bodies. A specific tau protein immunoblotting pattern different from that seen in Alzheimer's disease and certain other disorders has been suggested in some studies. A specific molecular marker and a genetic locus for familial cases are not known.
Dementia with Grains (Argyrophilic Grain Disease)
Authors: Jellinger Kurt A.
Published: July 2010

Dementia with grains, also referred to as argyrophilic grain disease, is a morphological condition in elderly individuals histologically characterised by the widespread occurrence of minute, spindle or comma‐shaped argyrophilic, tau‐immunoreactive structures distinct from neuropil threads that are predominantly located in the hippocampus and related limbic areas including the amygdala. They are suggested to arise mainly in dendrites of neurons showing accumulation of hyperphosphorylated tau proteins (pretangle stage) but not necessarily forming paired helical filaments. Argyrophilic grains are associated with argyrophilic, tau‐positive oligodendroglial inclusions (“coiled bodies”) in the white matter, while astroglia are not affected. Argyrophilic grain disease is considered to be a progressive disorder that may or may not be associated with dementia, the grains occasionally being the only morphologic substrates of cognitive decline. They often occur in combination with neuritic Alzheimer‐type lesions (many corresponding to “limbic” Braak stages III and IV) or other neurodegenerative disorders, such as progressive supranuclear palsy, corticobasal degeneration, or Pick's disease. The prevalence and pathogenesis of this condition, its clinicopathologic correlations and nosological position among tau‐pathology related disorders await further elucidation.
Comparative Neuropathology of Kuru with the New Variant of Creutzfeldt‐Jakob Disease: Evidence for Strain of Agent Predominating Over Genotype of Host
Authors: McLean CA , Ironside JW , Alpers MP , Brown PW , Cervenakova L , Anderson RMcD , Masters CL
Published: July 2010

The three major influences on the phenotype of the transmissible spongiform encephalopathies are believed to be strain of agent, route of infection and host genotype. We have compared the pathologic profiles and genotypes of the new variant of Creutzfeldt‐Jakob disease (vCJD) and kuru. The comparison reveals that there are distinct lesional differences particularly in the prion protein (PrP) load and distribution as seen by immunohistochemistry. The clinico‐pathologic phenotypes and the genotypes of these two diseases are sufficiently different to suggest that the strain of agent may play a greater role than any presumptive common route of peripherally acquired infection.
Microvascular and Cellular Responses in the Optic Nerve of Rats with Acute Experimental Allergic Encephalomyelitis (EAE)
Authors: Hu Ping , Pollard John , Hunt Nicholas , Taylor Jude , Chan‐Ling Tailoi
Published: July 2010

The optic nerve of rats with EAE was examined at various times to determine the integrity of the blood‐brain barrier (BBB) and to assess monocyte‐macrophage, T cell, and microglial responses. In naive control animals, leakage of horseradish peroxidase (HRP) and the presence of cells expressing major histocompatibility complex (MHC) class II antigen were evident in the meninges of the retrobulbar optic nerve. In rats with EAE, microglia in the region of the lamina cribrosa and in the regions adjacent to the meninges became activated from day 7 to 8 postinduction (pi). HRP leakage was also evident in the region of the lamina cribrosa from day 7 to 8 pi. On day 8 pi, infiltration of inflammatory cells and Monastral blue leakage were apparent in the myelinated region of the optic nerve. The intensity of these cellular and vascular changes peaked at day 12 pi, when signs of clinical disease became manifest. Monocytes‐macrophages expressing MHC class II and the ED1 antigen, together with lymphocytes expressing the αβT cell receptor, constituted the major proportion of cells associated with inflammatory lesions. Thus: (i) the inherent weakness of the BBB as well as the presence of both antigen (myelin) and MHC class II’cells in the retrobulbar optic nerve are likely susceptibility factors for the frequent involvement of this region in EAE and multiple sclerosis; and (ii) activation of microglia occurs early in the pathogenesis of experimental optic neuritis.
Microvascular and Cellular Responses in the Retina of Rats with Acute Experimental Allergic Encephalomyelitis (EAE)
Authors: Hu Ping , Pollard John , Hunt Nicholas , Chan‐Ling Tailoi
Published: July 2010

The microvascular and cellular responses in the retina during acute EAE were characterized using whole‐mount preparations. The earliest detectable event was the accumulation of monocytes and T cells within veins on day 7 postinduction (pi). Mild breakdown of the blood‐retinal barrier (BRB), activation of microglia and infiltration of monocytes and T cells into the retinal parenchyma were first evident on days 7 to 8 pi. Monocyte adhesion to the vessel wall and breakdown of the BRB were colocalized in the same vessel segments and occurred predominantly in veins. The marked difference in response observed in the retina versus the myelinated region of the optic nerve suggests that two types of inflammatory cascades are initiated. A mild response, characterised by very low numbers of T cells and monocytes and an absence of expression of MHC class II by resident microglia, is initiated when only small amounts of the encephalitogenic antigen are present in the perivascular space or associated with perivascular antigen‐presenting cells. A full blown inflammatory reaction, as observed in the optic nerve, is initiated in the presence of substantial amounts of encephalitogenic antigen. This severe response is characterised by the infiltration of large numbers of CD4+, CD8+T cells and ED1+ monocytes, and by abundant MHC class II expression by resident microglia as well as other cell types. Thus, MHC class II expression by resident microglia may be a possible effective amplifier mechanism if the encephalitogenic antigen is encountered in the tissue parenchyma.
Neuronal Apoptosis in Fatal Familial Insomnia
Authors: Dorandeu Anne , Wingertsmann Laure , Chrétien Fabrice , Delisle Marie‐Bernadette , Vital Claude , Parchi Piero , Montagna Pasquale , Lugaresi Elio , Ironside James W. , Budka Herbert , Gambetti Pierluigi , Gray Françoise
Published: July 2010

The possibility that neuronal loss in prion diseases occurs through an apoptotic process has been postulated and is consistent with the lack of inflammation in these disorders. In order to test this hypothesis in FFI, in which neuronal loss is the predominant neuropathological feature, we examined samples of thalamus, basal ganglia, cerebral cortex, cerebellum and medulla from 10 subjects with FFI. All the patients had the characteristic 178 N mutation of the PrP gene. Eight subjects were homozygous methionine/methionine at codon 129 and 2 were heterozygous methionine/valine. Apoptotic neurons were identified by in situ end labelling in all the FFI cases and in none of the controls. They were mostly found in damaged regions and their presence and abundance seemed to correlate closely with the neuronal loss. They were particularly abundant in the thalamus and medullary olives. In heterozygous cases who had a longer disease duration and more widespread cerebral changes, apoptotic neurons were also found in the neocortex and striatum. The abundance of apoptotic neurons also correlated well with microglial activation as demonstrated by the expression of major histocompatibility complex class II antigens. PrPres immunostaining was almost invariably negative, consistent with previous data showing the lack of obvious correlation between neuronal loss and PrPres deposits in prion diseases.
The Bacterial Endotoxin Lipopolysaccharide has the Ability to Target the Brain in Upregulating Its Membrane CD14 Receptor Within Specific Cellular Populations
Authors: Lacroix Steve , Feinstein Doug , Rivest Serge
Published: July 2010

Systemic injection of the bacterial endotoxin lipopolysaccharide (LPS) provides a very good mean for increasing the release of proinflammatory cytokines by circulating monocytes and tissue macrophages. There is now considerable evidence that LPS exerts its action on mononuclear phagocytes via the cell surface receptor CD14. The aim of the present study was to verify the hypothesis that the brain has also the ability to express the gene encoding the LPS receptor, which may allow a direct action of the endotoxin onto specific cellular populations during blood sepsis. Adult male Sprague‐Dawley rats were sacrificed 1, 3, 6 and 24 h after systemic (i.v. or i.p.) injection of LPS or the vehicle solution. Brains were cut from the olfactory bulb to the medulla in 30‐μm coronal sections and mRNA encoding rat CD14 was assayed byin situhybridization histochemistry using a specific35S‐labeled riboprobe. The results show low levels of CD14 mRNA in the leptomeninges, choroid plexus and along blood vessels of the brain microvasculature under basal conditions. Systemic injection of the bacterial endotoxin caused a profound increase in the expression of the gene encoding CD14 within these same structures as well as in the circumventricular organs (CVOs) the organum vasculosum of the lamina terminalis, subfornical organ, median eminence and area postrema. In most of these structures, the signal for CD14 mRNA was first detected at 1 h, reached a peak at 3 h post‐injection, declined at 6 h, and return to basal levels 24 h after LPS treatment. Quite interestingly, a migratory‐like pattern of CD14 positive cells was observed from all sensorial CVOs to deeper parenchymal brain 3 and 6 h after LPS injection. At 6 h post‐challenge, small positive cells were found throughout the entire parenchymal brain and dual‐labeling procedure indicated that different cells of myeloid origin have the ability to express CD14 in response to systemic LPS. These included CVO microglia, choroid plexus and leptomeninge macrophages, parenchymal and perivascular‐associated microglial cells, although specific nonmyeloid cells were also positive for the LPS receptor. These results provide the very first evidence of a direct role of LPS on specific cell populations of the central nervous system, which is likely to be responsible for the transcription of proinflammatory cytokines; first within accessible structures from the blood and thereafter through scattered parenchymal cells during severe sepsis.
Supratentorial Pilocytic Astrocytomas, Astrocytomas, Anaplastic Astrocytomas and Glioblastomas are Characterized by a Differential Expression of S100 Proteins
Authors: Camby Isabelle , Nagy Nathalie , Lopes Maria‐Beatriz , Schäfer Beat W. , Maurage Claude‐Alain , Ruchoux Marie‐Magdeleine , Murmann Petra , Pochet Roland , Heizmann Claus W. , Brotchi Jacques , Salmon Isabelle , Kiss Robert , Decaestecker Christine
Published: July 2010

The levels of expression of the S100A1, S100A2, S100A3, S100A4, S100A5, S100A6 and S100B proteins were immunohistochemically assayed and quantitatively determined in a series of 95 astrocytic tumors including 26 World Health Organization (WHO) grade I (pilocytic astrocytomas), 23 WHO grade II (astrocytomas), 25 WHO grade III (anaplastic astrocytomas) and 21 WHO grade IV (glioblastomas) cases. The level of the immunohistochemical expression of the S100 proteins was quantitatively determined in the solid tumor tissue (tumor mass). In addition twenty blood vessel walls and their corresponding perivascular tumor astrocytes were also immunohistochemically assayed for 10 cases chosen at random from each of the four histopathological groups. The data showed modifications in the level of S100A3 protein expression; these modifications clearly identified the pilocytic astrocytomas from WHO grade II‐IV astrocytic tumors as a distinct biological group. Modifications in the level of S100A6 protein expression enabled a clear distinction to be made between low (WHO grade I and II) and high (WHO grade III and IV) grade astrocytic tumors. Very significant modifications occurred in the level of S100A1 protein expression (and, to a lesser extent, in their of the S100A4 and S100B proteins) in relation to the increasing levels of malignancy. While the S100A5 protein was significantly expressed in all the astrocytic tumors (but without any significant modifications in the levels of malignancy), the S100A2 protein was never expressed in these tumors. These data thus indicate that several S100 proteins play major biological roles in human astrocytic tumors.
Co‐Localization of TSC1 and TSC2 Gene Products in Tubers of Patients with Tuberous Sclerosis
Authors: Johnson Michael W. , Emelin Jessica K. , Park Sung‐Hye , Vinters Harry v.
Published: July 2010

Two genes, mutations in which result in the phenotype of tuberous sclerosis (TSC), have recently been cloned. TSC2 on chromosome 16p 13.3 encodes the protein tuberin, which appears to have growth regulating properties. TSC1 on chromosome 9q34 encodes hamartin which, as yet, has no specified cellular functions. Polyclonal antibodies were raised to synthetic peptides representing portions of tuberin and hamartin and used in immunoblots and immunohistochemical studies to localize the proteins in surgically resected neocortical tubers from four TSC patients. On Western blots of autopsy brain specimens, K‐562 cell, and NT2 lysates, each antibody labelled a single band at the expected molecular weight. In immunohistochemical protocols on paraffin embedded tissue, antibodies to both tuberin and hamartin prominently labelled atypical and dysmorphic neuroglial cells that are a defining feature of TSC tubers. Some abnormal cells within cortical tuber sections were labelled with both tuberin and hamartin antisera. Our results suggest that tuberin and hamartin are both robustly expressed in similar populations of neuroglial cells of TSC tubers, even in the presence of TSC1 or TSC2 germline mutations. The roles of these gene products in normal and abnormal cortical development, tuber pathogenesis and the generation of seizures remain to be defined.
Oxidative Stress in Bacterial Meningitis
Authors: Koedel Uwe , Pfister Hans‐Walter
Published: July 2010

Fifty years after the advent of antibiotics for clinical use, the rates of morbidity and mortality associated with bacterial meningitis remain high. The unfavourable clinical outcome is often due to intracranial complications including cerebrovascular insults, raised intracranial pressure, hydrocephalus, and brain edema. Reactive oxygen species (ROS) are known effector molecules in the antimicrobial armature of polymorphonuclear and mononuclear phagocytes. However, over the last decade, there has been a substantial body of work implicating a central role of ROS in the development of intracranial complications and brain damage in bacterial meningitis. Recently, it also became evident that reactive nitrogen species (RNS), especially nitric oxide, are important mediators of meningitis‐associated pathophysiological changes, at least during the early phase of the disease. There is now substantial evidence that much of the oxidative injury associated by simultaneous production of superoxide and nitric oxide is mediated by the strong oxidant peroxynitrite. ROS and peroxynitrite can be cytotoxic via a number of independent mechanisms. Their cytotoxic effects include initiation of lipid peroxidation and induction of DNA single strand breakage. Damaged DNA activates poly(ADP‐ribose) polymerase (PARP). Recent experimental data propose a role of lipid peroxidation and PARP activation in the development of meningitis‐associated intracranial complications and brain injury. Agents which interfere with the production of ROS and peroxynitrite, as well as with PARP activation and lipid peroxidation may represent novel, therapeutic strategies to limit meningitis‐associated brain damage, and, thus, to improve the outcome of this serious disease.
Oxidative Metabolism, Apoptosis and Perinatal Brain Injury
Authors: Taylor Deanna L. , Edwards A. David , Mehmet Huseyin
Published: July 2010

Perinatal hypoxic‐ischaemic injury (HII) is a significant cause of neurodevelopmental impairment and disability. Studies employing 31P magnetic resonance spectroscopy to measure phosphorus metabolites in situ in the brains of newborn infants and animals have demonstrated that transient hypoxia‐ischaemia leads to a delayed disruption in cerebral energy metabolism, the magnitude of which correlates with the subsequent neurodevelopmental impairment.

Prominent among the biochemical features of HII is the loss of cellular ATP, resulting in increased intracellular Na+ and Ca2+, and decreased intracellular K+.These ionic imbalances, together with a breakdown in cellular defence systems following HII, can contribute to oxidative stress with a net increase in reactive oxygen species. Subsequent damage to lipids, proteins, and DNA and inactivation of key cellular enzymes leads ultimately to cell death.

Although the precise mechanisms of neuronal loss are unclear, it is now clear both apoptosis and necrosis are the significant components of cell death following HII. A number of different factors influence whether a cell will undergo apoptosis or necrosis, including the stage of development, cell type, severity of mitochondrial injury and the availability of ATP for apoptotic execution.

This review will focus on some pathological mechanisms of cell death in which there is a disruption to oxidative metabolism. The first sections will discuss the process of damage to oxidative metabolism, covering the data collected both from human infants and from animal models. Following sections will deal with the molecular mechanisms that may underlie cerebral energy failure and cell death in this form of brain injury, with a particular emphasis on the role of apoptosis and mitochondria.