bluuebunny/crossref_metadata_2025 huggingface dataset:
Macular thickness and systemic markers for diabetes in individuals with no or mild diabetic retinopathy
Authors: Asefzadeh Baharak , Fisch Barry M , Parenteau Chad E , Cavallerano Anthony A
Published: August 2008

Abstract

Background:  The relationship between diabetic risk factors and macular thickness in individuals without clinically detectable diabetic macular oedema has yet to be formally explored. The purpose of this study was to assess the correlation between macular thickness and diabetes control and duration.

Methods:  This was a prospective, cross‐sectional study. All subjects underwent digital retinal imaging and Stratus OCT macular thickness scanning both eyes. Mean retinal thickness was determined for quadrants, rings, hemispheres, and for the central fovea (CFT), total fovea (TFT) and total macula (TMT).

Results:  We evaluated 92 non‐diabetic controls, 92 diabetic subjects with no diabetic retinopathy (DR) and 24 subjects with mild DR at the Veteran's Hospital in Jamaica Plain, MA. In subjects with diabetes, there was a significant negative correlation between retinal thickness and diabetes duration in all macular quadrants, rings and hemispheres, and for CFT, TFT and TMT (CFT: P = 0.0025, r = −0.28; TFT: P = 0.0062, r = −0.25; TMT: P = 0.0026, r = −0.28). There was no significant relationship between retinal thickness and HbA1c level (average of last three readings), systolic or diastolic blood pressure, or triglyceride levels. Additionally, no significant differences in retinal thickness were found between controls, subjects with no DR and subjects with mild DR.

Conclusions:  In subjects with no or mild DR, macular and foveal thickness is significantly thinner with longer duration of disease. This may reflect neurodegenerative changes in the diabetic retina.
Osteolipoma of the eyelid
Authors: Kumar Sandeep , Kumar Sanjiv , Kulshrestha Ritu
Published: August 2008

Abstract

A 50‐year‐old woman presented with a nodular swelling on her right upper eyelid. The tumour was diagnosed as osteolipoma histologically after resection. Osteolipoma is a very rare variant of lipoma and only a few cases affecting the head and neck are reported in literature. To the best of the author's knowledge this is the first reported case of osteolipoma of the eyelid.
Lung metastases in a case of metatypical basal cell carcinoma of the eyelid: an illustrative case and literature review to heighten vigilance of its metastatic potential
Authors: Cunneen Thomas S , Yong Jim L , Benger Ross
Published: August 2008

Abstract

Basal cell carcinoma (BCC) is an extremely common malignancy; however, unlike other skin cancers, they very rarely metastasize. Here we present an unusual case of metatypical BCC of the eyelid which metastasized to the lung nine years after initial surgical treatment. We include a review of the literature regarding metastatic BCC and suggest that metatypical features in primary BCC should prompt careful patient monitoring and consideration of adjuvant treatment at the time of diagnosis.
Chondrocranium and skeletal development of Phrynops hilarii (Pleurodira: Chelidae)
Authors: Bona Paula , Alcalde Leandro
Published: August 2008

The present study represents the first comprehensive contribution to the knowledge of the skeletal development of a pleurodiran turtle, Phrynops hilarii (Pleurodira, Chelidae). The most remarkable features found are: (1) absence of ascending process on pterygoquadrate cartilage; (2) presence of ossification centres for the epiotics; (3) as in other pleurodirans, dorsal ribs IX and X are ‘sacralized’; (4) contact between ilium and carapace occurs later in ontogenetic development; (5) suture between ischia, pubes and plastron occurs in posthatching specimens; (6) contrary to previous interpretations, the phalangeal formula of the pes of P. hilarii is 2 : 3 : 3 : 3 : 5; (7) the hooked bone represents the fifth metatarsal.
Down‐regulation of GhADF1 gene expression affects cotton fibre properties
Authors: Wang Hai‐Yun , Wang Juan , Gao Peng , Jiao Gai‐Li , Zhao Pi‐Ming , Li Yan , Wang Gui‐Ling , Xia Gui‐Xian
Published: August 2008

Cotton fibre is the most important natural fibres for textile industry. To date, the mechanism that governs the development of fibre traits is largely unknown. In this study, we have characterized the function of a member of the actin depolymerizing factor (ADF) family in Gossypium hirsutum by down‐regulation of the gene (designated as GhADF1) expression in the transgenic cotton plants. We observed that both the fibre length and strength of the GhADF1‐underexpressing plants increased as compared to the wild‐type fibre, and transgenic fibres contained more abundant F‐actin filaments in the cortical region of the cells. Moreover, the secondary cell wall of the transgenic fibre appeared thicker and the cellulose content was higher than that of the control fibre. Our results suggest that organization of actin cytoskeleton regulated by actin‐associated proteins such as GhADF1 plays a critical role in the processes of elongation and secondary cell wall formation during fibre development. Additionally, our study provided a candidate intrinsic gene for the improvement of fibre traits via genetic engineering.
Use and performances of Web‐based portfolio assessment
Authors: Chang Chi‐Cheng , Tseng Kuo‐Hung
Published: August 2008

This research explored the influence of a Web‐based portfolio assessment system on students' performances. The methodological procedure adopted was to have the experimental group use the system, with the control group using conventional assessment. The study subjects were junior high school students of two computer classes. The experimental results revealed that the use of the system has significant positive influence on students' performances. According to estimated effect size, the most significant indicators were reflection, self‐assessment, continuous improvement, goal setting, problem solving, data gathering, work and peer interaction. However, peer‐assessment performance was not enhanced significantly. Therefore, one recommendation was to reduce peer‐assessment and instead offer specific illustrations to the students as well as the opportunity to drill.
A measure of the effectiveness of incorporating 3D human anatomy into an online undergraduate laboratory
Authors: Hilbelink Amy J.
Published: August 2008

Results of a study designed to determine the effectiveness of implementing three‐dimensional (3D) stereo images of a human skull in an undergraduate human anatomy online laboratory were gathered and analysed. Mental model theory and its applications to 3D relationships are discussed along with the research results. Quantitative results on 62 pairs were analysed using a doubly‐multivariate analysis of variance repeated measures design. Results revealed statistically significant differences in group means for the main effect of treatment groups 2D and 3D and for the variables of Identification and Relationship with the 3D group outperforming the 2D group on both dependent variables.
Submitting to Defeat
Authors: Maner Jon K. , Miller Saul L. , Schmidt Norman B. , Eckel Lisa A.
Published: August 2008

Although theory suggests a link between social anxiety and social dominance, direct empirical evidence for this link is limited. The present experiment tested the hypothesis that socially anxious individuals, particularly men, would respond to a social-dominance threat by exhibiting decrements in their testosterone levels, an endocrinological change that typically reflects pronounced social submission in humans and other animals. Participants were randomly assigned to either win or lose a rigged face-to-face competition with a confederate. Although no zero-order relationship between social anxiety and level of testosterone was observed, testosterone levels showed a pronounced drop among socially anxious men who lost the competition. No significant changes were observed in nonanxious men or in women. This research provides novel insight into the nature and consequences of social anxiety, and also illustrates the utility of integrating social psychological theory with endocrinological approaches to psychological science.
Sleep Preferentially Enhances Memory for Emotional Components of Scenes
Authors: Payne Jessica D. , Stickgold Robert , Swanberg Kelley , Kensinger Elizabeth A.
Published: August 2008

Central aspects of emotional experiences are often well remembered at the expense of background details. Previous studies of such memory trade-offs have focused on memory after brief delays, but little is known about how these components of emotional memories change over time. We investigated the evolution of memory for negative scenes across 30 min, 12 daytime hours spent awake, and 12 nighttime hours including sleep. After 30 min, negative objects were well remembered at the expense of information about their backgrounds. Time spent awake led to forgetting of the entire negative scene, with memories of objects and their backgrounds decaying at similar rates. Sleep, in contrast, led to a preservation of memories of negative objects, but not their backgrounds, a result suggesting that the two components undergo differential processing during sleep. Memory for a negative scene develops differentially across time delays containing sleep and wake, with sleep selectively consolidating those aspects of memory that are of greatest value to the organism.
Variation and the indexical field1
Authors: Eckert Penelope
Published: August 2008

This paper argues for a focus on the social meaning of variation, based in a study of stylistic practice. It is common in the study of variation to interpret variables as reflections of speakers' membership in social categories. Others have argued more recently that variables are associated not with the categories themselves, but with stances and characteristics that constitute those categories. The paper reviews some variation studies that show that variables do not have static meanings, but rather general meanings that become more specific in the context of styles. Building on Michael Silverstein's notion of indexical order, I argue that the meanings of variables are not precise or fixed but rather constitute a field of potential meanings – an indexical field, or constellation of ideologically related meanings, any one of which can be activated in the situated use of the variable. The field is fluid, and each new activation has the potential to change the field by building on ideological connections. Thus variation constitutes an indexical system that embeds ideology in language and that is in turn part and parcel of the construction of ideology.
Alternate and complementary perspectives on language and social life: The organization of repair in two Caribbean communities1
Authors: Sidnell Jack
Published: August 2008

This article discusses the history of relations between conversation analysis and linguistic anthropology within the broader field encompassing various approaches to language, interaction, and social life. It argues that although these relations have, at times, been fraught and marked by rather serious misconceptions of what conversation analysis is all about, there is still much to be gained from cooperation and scholarly exchange between these approaches. An illustration of this argument focuses on the organization of other‐initiated repair in two Caribbean communities.
All of the above: New coalitions in sociocultural linguistics1
Authors: Bucholtz Mary , Hall Kira
Published: August 2008

As the history of sociolinguistics and linguistic anthropology shows, a sharp distinction between these fields and others concerned with the sociocultural investigation of language is untenable given their significant common ground. The article describes the current state of relations between sociolinguistics, linguistic anthropology, and similar approaches to language, culture, and society. It then locates theoretical, methodological, thematic, and political points of commonality and explores emerging areas of productive dialogue among these closely overlapping research traditions. Two analytic examples, one focused on race talk in sociolinguistic interviews with European American youth and the other on ideologies of English among sexual and gender minorities in India, illustrate the benefits of bringing together different branches of sociolinguistics and linguistic anthropology.
Fractured Phenomenologies: Thought Insertion, Inner Speech, and the Puzzle of Extraneity
Authors: LANGLAND‐HASSAN PETER
Published: August 2008

Abstract:  How it is that one’s own thoughts can seem to be someone else’s? After noting some common missteps of other approaches to this puzzle, I develop a novel cognitive solution, drawing on and critiquing theories that understand inserted thoughts and auditory verbal hallucinations in schizophrenia as stemming from mismatches between predicted and actual sensory feedback. Considerable attention is paid to forging links between the first‐person phenomenology of thought insertion and the posits (e.g. efference copy, corollary discharge) of current cognitive theories. I show how deficits in the subconscious mechanisms regulating inner speech may lead to a ‘fractured phenomenology’ responsible for schizophrenic patients’ reports of inserted thoughts and auditory verbal hallucinations. Supporting work on virtual environments is discussed, and lessons concerning the fixity of delusional belief are drawn.
Free Enrichment or Hidden Indexicals?
Authors: HALL ALISON
Published: August 2008

Abstract: A current debate in semantics and pragmatics is whether all contextual effects on truth‐conditional content can be traced to logical form, or ‘unarticulated constituents’ can be supplied by the pragmatic process of free enrichment. In this paper, I defend the latter position. The main objection to this view is that free enrichment appears to overgenerate, not predicting where context cannot affect truth conditions, so that a systematic account is unlikely (Stanley, 2002a). I first examine the semantic alternative proposed by Stanley and others, which assumes extensive hidden structure acting as a linguistic trigger for pragmatic processes, so that all truth‐conditional effects of context turn out to be instances of saturation. I show that there are cases of optional pragmatic contributions to the proposition expressed that cannot plausibly be accounted for in this way, and that advocates of this approach will therefore also have to appeal to free enrichment. The final section starts to address the question of how free enrichment is constrained: I argue that it involves only local development or adjustment of parts of logical form, any global developments being excluded by the requirement for the proposition expressed to provide an inferential warrant for the intended implications of the utterance.
Vision, Action, and Make‐Perceive
Authors: BRISCOE ROBERT EAMON
Published: August 2008

Abstract: In this paper, I critically assess the enactive account of visual perception recently defended by AlvaNoë (2004). I argueinter aliathat the enactive account falsely identifies an object’s apparent shape with its 2D perspectival shape; that it mistakenly assimilates visual shape perception and volumetric object recognition; and that it seriously misrepresents the constitutive role of bodily action in visual awareness. I argue further that noticing an object’s perspectival shape involves a hybrid experience combining both perceptual and imaginative elements—an act of what I call ‘make‐perceive’.
Brain atrophy as a marker of cognitive impairment in mildly disabling relapsing–remitting multiple sclerosis
Authors: Sánchez M. P. , Nieto A. , Barroso J. , Martín V. , Hernández M. A.
Published: August 2008

Background and purpose:  We have studied the relationship between neuropsychological impairment and magnetic resonance imaging (MRI) measures in mildly disabling relapsing–remitting multiple sclerosis (RRMS).

Methods:  We compared measures of lesion burden and atrophy in 52 patients with Expanded Disability Status Scale ≤ 3.0. Neuropsychological testing explored various cognitive domains: attention and processing speed (APS), verbal and visual memory (VerbM; VisM), visual/constructional processes (VC), executive functions and motor programming/coordination. Specific and global index scores were derived to classify patients as deteriorated or not deteriorated by comparing their performance with 51 matched normal control subjects. Brain MRI analysis included proton density (PD)‐lesion volume and T1‐hypointensity volume, measures of central atrophy, including the third ventricle width, and corpus callosum (CC).

Results:  Patients with either APS, MCP or Verbal Learning impairments had a higher ventricular atrophy than unimpaired. The atrophy of the CC was only associated to VisM dysfunction. Patients with VisM deficits had higher lesion load on PD images. After controlling for age and education a higher third ventricle width was the best predictor for global and specific cognitive impairment.

Conclusion:  Our results suggest that cognitive impairment in RR patients with mild disease is better explained by atrophic changes than by total lesion load.
Concordance and heritability of multiple sclerosis in Finland: study on a nationwide series of twins
Authors: Kuusisto H. , Kaprio J. , Kinnunen E. , Luukkaala T. , Koskenvuo M. , Elovaara I.
Published: August 2008

Objectives:  To evaluate the changes in the multiple sclerosis (MS) concordance in twins, and the contribution of genetic and environmental factors to the aetiology of MS in Finland.

Background:  Both genes and the environment contribute to the development of MS. A well‐conducted twin study is an excellent means to assess the relative contribution of heritability and environmental factors.

Methods:  Multiple sclerosis concordance was assessed for 10 Monozygotic and 14 dizygotic twin pairs using pairwise and probandwise concordance rates. The tetrachoric correlations in liability to disease for twin pairs were computed and a polygenic multifactorial model was used to estimate heritability.

Results:  The pairwise concordance for MZ twins was 30% and for the DZ twins 14.3%, compared with 30% for MZ and 0% for DZ 20 years ago. The corresponding probandwise concordance rates were 46.2% and 25%. The genetic variance (heritability) was 15.3% (95% Cl 0.0–77.6), the common environmental variance 73.7% (95% Cl 14.1–93.9) and the unique environmental variance 11.1% (95% Cl 2.3–30.0).

Conclusions:  As the concordance of MS in DZ twins has increased during the past two decades and the heritability estimate is low, it seems that the reported increase in MS incidence in Finland is mainly caused by environmental factors.
From banger to classic – a model for sustainable car consumption?
Authors: Nieuwenhuis Paul
Published: August 2008

Cars are the most complex of consumer durables, yet they are not as durable as one may expect. Each year, millions of cars are scrapped, many still roadworthy or easily repairable. As with other consumer durables, consumers increasingly lose their emotional attachment with their old car in favour of a younger model. Is it possible to remedy this failure of consumer–product relationships in the interest of greater product durability and hence greater environmental sustainability? This paper explores this question in the context of the classic car market and suggests there may be some lessons there that could lead to a more sustainable new car consumption culture.
Mutation in aging mice occurs in diverse cell types that proliferate postmutation
Authors: Fischer Jared M. , Stringer James R.
Published: August 2008

To determine the relationship between aging, cell proliferation and mutation in different cell types, hearts, brains and kidneys from G11 PLAP mice between 1 week and 24 months of age were examined. Mutant cells were detected in tissue sections by staining for Placental Alkaline Phosphatase (PLAP) activity, an activity that marks cells that have sustained a frameshift mutation in a mononucleotide tract inserted into the coding region of the human gene encoding PLAP. The number of PLAP+ cells increased with age in all three tissues. The types of cells exhibiting a mutant phenotype included cells that are proliferative, such as kidney epithelial cells, and cells that do not frequently replicate, such as cardiac muscle cells and neurons. In the brain, PLAP+ cells appeared in various locations and occurred at similar frequencies in different regions. Within the cerebellum, PLAP+ Purkinje cell neurons appeared at a rate similar to that seen in the brain as a whole. PLAP+ cells were observed in kidney‐specific cell types such as those in glomeruli and collecting tubules, as well as in connective tissue and blood vessels. In the heart, PLAP+ cells appeared to be cardiac muscle cells. Regardless of tissue and cell type, PLAP+ cells occurred as singletons and in clusters, both of which increased in frequency with age. These data show that age‐associated accumulation of mutant cells occurs in diverse cell types and is due to both new mutation and proliferation of mutant cells, even in cell types that tend to not proliferate.
Partial melting of metagreywacke: a calculated mineral equilibria study
Authors: JOHNSON T. E. , WHITE R.W. , POWELL R.
Published: August 2008

Greywacke occurs in most regionally metamorphosed orogenic terranes, with depositional ages from Archean to recent. It is commonly the dominant siliciclastic rock type, many times more abundant than pelite. Using calculated pseudosections in the Na2O–CaO–K2O–FeO–MgO–Al2O3–SiO2–H2O–TiO2–O system, the partial melting of metagreywacke is investigated using several natural protolith compositions that reflect the main observed compositional variations. At conditions appropriate for regional metamorphism at mid‐crustal depths (6–8 kbar), high‐Tsubsolidus assemblages are dominated by quartz, plagioclase and biotite with minor garnet, orthoamphibole, sillimanite, muscovite and/or K‐feldspar (±Fe–Ti oxides). Modelled solidus temperatures are dependent on bulk composition and vary from 640 to 690 °C. Assuming minimal melting at the H2O‐saturated solidus, initial prograde anatexis at temperatures up to ∼800 °C is characterized by very low melt productivity. Significant melt production in commonly occurring (intermediate) metagreywacke compositions is controlled by the breakdown of biotite and production of orthopyroxene (±K‐feldspar) across multivariant fields until biotite is exhausted at 850–900 °C. Assuming some melt is retained in the source, then at temperatures beyond that of biotite stability, melt production occurs via the consumption of plagioclase, quartz and any remaining K‐feldspar as the melt becomes progressively more Ca‐rich and H2O‐undersaturated. Melt productivity with increasing temperature across the melting interval in metagreywacke is generally gradational when compared to metapelite, which is characterized by more step‐like melt production. Comparison of the calculated phase relations with experimental data shows good consistency once the latter are considered in terms of the variance of the equilibria involved. Calculations on the presumed protolith compositions of residual granulite facies metagreywacke from the Archean Ashuanipi subprovince (Quebec) show good agreement with observed phase relations. The degree of melt production and subsequent melt loss is consistent with the previously inferred petrogenesis based on geochemical mass balance. The results show that, for temperatures above 850 °C, metagreywacke is sufficiently fertile to produce large volumes of melt, the separation from source and ascent of which may result in large‐scale crustal differentiation if metagreywacke is abundant.
The association between central nervous system (CNS) infections and epilepsy: Epidemiological approaches and microbiological and epileptological perspectives
Authors: Singh Gagandeep , Prabhakar Sudesh
Published: August 2008

Summary

The causal association between central nervous system (CNS) infections and epilepsy is predictable but poorly documented due to constraints in epidemiological, epileptological, and microbiologic methods. The large number of CNS infections with varied geographic distributions means that epidemiological studies in many different regions are required in order to establish their association with epilepsy. Whenever infectious diseases occur in the community, the majority of the infected cases are either asymptomatic or develop only mild symptoms. Those with neurological involvement and hence at risk of developing epilepsy constitute the tip of the iceberg. Furthermore, there is no one‐to‐one relationship between surrogate markers of infection used in epidemiological studies (e.g., seropositivity or brain imaging abnormalities) and neurological involvement (and hence epilepsy). As a result, there are individuals in the community who have no neurological symptoms but may either be seropositive or demonstrate imaging abnormalities compatible with the neurological infectious disorder and conversely, those who have seizures (or epilepsy) but may be seronegative. Relevant to the epidemiological study of seizures and epilepsy in relation to CNS infections is the classification of seizures as provoked and unprovoked. Accordingly, seizures that occur during the active stage of infection are considered provoked and those that occur later are unprovoked. Finally, with the burden of infections being concentrated in the less‐developed countries, epidemiological studies are required to be carried out in these locations, which present logistic, financial and technical barriers for them to be accomplished.
Bacterial meningitis and epilepsy
Authors: Murthy Jagaralapudi Murali K. , Prabhakar Sudesh
Published: August 2008

Summary

The high incidence and prevalence of epilepsy in developing countries has partly been attributed to an increased frequency of central nervous system (CNS) infections. Of the CNS infections, bacterial meningitis is endemic in many countries and several epidemics have also been reported in these regions. Unprovoked seizures and epilepsy (recurrent unprovoked seizures) can be long‐term sequelae of bacterial meningitis. The probability of developing an unprovoked seizure or epilepsy varies according to the etiologic agent responsible for meningitis and this probability appears to be higher for Streptococcus pneumoniae. The risk factors for late unprovoked seizures/epilepsy include early seizures during the acute phase of meningitis and persistent neurological deficits other than sensorineural hearing loss. The majority of unprovoked seizures occur within 5 years of the meningitis episode and tend to be recurrent. The burden of epilepsy associated with bacterial meningitis depends upon the incidence of the latter and hence is to some extent preventable. Implementing vaccination programs against the three most important meningeal pathogens can reduce the incidence of bacterial meningitis. In developed countries, a decline in the incidence of bacterial meningitis has been accomplished with the implementation of vaccination programs.
Viral encephalitis and epilepsy
Authors: Misra Usha Kant , Tan Chong Tin , Kalita Jayantee
Published: August 2008

Summary

Viral encephalitis presents with seizures not only in the acute stage but also increases the risk of late unprovoked seizures and epilepsy. Acute symptomatic and late unprovoked seizures in different viral encephalitides are reviewed here. Among the sporadic viral encephalitides, Herpes simplex encephalitis (HSE) is perhaps most frequently associated with epilepsy, which may often be severe. Seizures may be the presenting feature in 50% patients with HSE because of involvement of the highly epileptogenic frontotemporal cortex. The occurrence of seizures in HSE is associated with poor prognosis. In addition, chronic and relapsing forms of HSE have been described and these may be associated with antiepileptic drug‐resistant seizures. Among the epidemic (usually due to flaviviruses) viral encephalitides, Japanese encephalitis (JE) is most common and is associated with acute symptomatic seizures, especially in children. The reported frequency of acute symptomatic seizures in JE is 7–46%. Encephalitis due to other flaviviruses such as equine, St. Louis, and West Nile viruses may also manifest with acute symptomatic seizures. In Nipah virus encephalitis, seizures are more common in relapsed and late‐onset encephalitis in comparison to acute encephalitis (4% vs. 1.8%). Other viruses like measles, varicella, mumps, influenza, and entero‐viruses may cause seizures depending on the area of brain involved. There is no comprehensive data regarding late unprovoked seizures in different viral encephalitides. Prospective studies are required to document the risk of late unprovoked seizures and epilepsy following viral encephalitis due to different viruses as well as to determine the clinical characteristics, course, and outcome of post‐encephalitic epilepsy.
Helminthic parasites and seizures
Authors: Garcia Hector H. , Modi Manish
Published: August 2008

Summary

A large number of helminthic parasites are known to involve the central nervous system (CNS) and produce neurologic symptoms including seizures and epilepsy. Taenia solium (the pork tapeworm) is perhaps most widely prevalent and well known for its association with seizures and epilepsy. Many of the other helminthic disorders have fairly restricted geographic predilections and their occurrence in much of the remaining world is limited to rare cases among travelers and immigrants. Nonetheless, knowledge about the helminthic disorders, the life cycle of their causative agents, and their clinical manifestations and diagnostic features are important in order to recognize them.
Seizures in HIV‐seropositive individuals: NIMHANS experience and review
Authors: Satishchandra P. , Sinha Sanjib
Published: August 2008

Summary

Seizures are not uncommon in patients with human immunodeficiency virus (HIV) infection, and with the upsurge in HIV infection this may be an important cause for acute symptomatic seizures. Seizures may rarely be the presenting manifestation of HIV infection. Opportunistic infections such as toxoplasmosis, tuberculosis, progressive multifocal leucoencephalopathy (PML), cryptococcal meningitis and polymicrobial infections, metabolic and electrolyte disturbances, and drugs are common causes of new‐onset seizures in HIV‐seropositive individuals. In the absence of any cause, primary HIV infection may be considered responsible for seizures. Because seizures tend to recur in and because they are a poor prognostic indicator in HIV infection, treatment with antiepileptic drugs (AEDs) is the norm. The treatment of HIV‐infected individuals with seizures comprises of the administration of AEDs, specific treatment of the underlying conditions, and antiretroviral drugs. Clinicians must consider both therapy‐compromising drug–drug and drug–disease interactions while choosing appropriate AEDs. The ideal AED in this setting is one that does not affect viral replication, have limited protein binding, and have no effects on the hepatic cytochrome P450 enzyme system. The risks for AED‐induced allergic skin rash appears to be high in HIV‐seropositive individuals.
The effects of antimicrobial and antiepileptic treatment on the outcome of epilepsy associated with central nervous system (CNS) infections
Authors: Singh Gagandeep , Prabhakar Sudesh
Published: August 2008

Summary

The course and outcome of epilepsy following central nervous system (CNS) infections has been poorly characterized. Likewise, the impact of antimicrobial treatment as well as other preventative and therapeutic interventions on the development of epilepsy following neurological infectious disorders has been insufficiently studied. The CNS infections that can cause epilepsy may be either acute or chronic‐recurrent. For most acute infections, for example, viral encephalitis and bacterial meningitis, the effect of specific antimicrobial treatment on the development of epilepsy cannot be studied in a controlled manner due to logistic and ethical reasons. In the specific case of neurocysticercosis (NCC), the risk of seizures in the short term is reduced following either anthelminthic or corticosteroid treatment or both. The effect of anthelminthic treatment on seizure outcome in the long term has not been studied. Finally, treatment with antiepileptic drugs (AEDs) needs to be optimally defined in the case of epilepsy associated with neurological infectious disorders.
Perspectives on interactions between antiepileptic drugs (AEDs) and antimicrobial agents
Authors: Desai Joy
Published: August 2008

Summary

In the treatment of seizures and epilepsy associated with central nervous system (CNS) infections, drug–drug interactions may significantly and unexpectedly impact outcome not only of epilepsy but also of the infectious disorders in both emergent and chronic care situations. A case is described in whom, the administration of the antimicrobial agent, meropenem presumably reduced serum valproate concentrations resulting in impaired seizure control. Other situations are reviewed in which interactions between antiepileptic drugs (AEDs) and antimicrobial agents may be of clinical significance. These include: (1) seizure management in individuals with neurocysticercosis, (2) management of seizures in patients with lobar tuberculomas, (3) management of seizures due to cerebral abscess, and (4) management of seizures in HIV‐seropositive individuals.
Status epilepticus produces chronic alterations in cardiac sympathovagal balance
Authors: Metcalf Cameron S. , Radwanski Przemyslaw B. , Bealer Steven L.
Published: August 2008

Purpose:  Status epilepticus (SE) activates the autonomic nervous system, increasing sympathetic nervous system control of cardiac function during seizure activity. However, lasting effects of SE on autonomic regulation of the heart, which may contribute to mortality following seizure activity, are unknown. Therefore, autonomic control of cardiac function was assessed following SE.

Methods:  Using Sprague‐Dawley rats after 1–2 weeks of recovery from lithium‐pilocarpine‐induced SE or control procedures, we tested  overall sympathovagal control of the heart, the individual contributions of the sympathetic and parasympathetic components of the autonomic nervous system, and baroreflex sensitivity.

Results:  SE induced a chronic shift in sympathovagal balance toward sympathetic dominance resulting from decreased parasympathetic activity. Baroreflex sensitivity to increased blood pressure was also decreased, likely resulting from diminished vagal activation.

Discussion:  Chronic alterations in autonomic regulation of cardiac function, characterized by increased sympathetic dominance, occur following SE and likely contribute to subsequent increased cardiac risk and mortality.
Cellular mechanisms of cobalt‐induced hippocampal epileptiform discharges
Authors: He Jiwei , Hsiang Hwa‐Lin , Wu Chiping , Mylvagnanam Shanthini , Carlen Peter L. , Zhang Liang
Published: August 2008

Purpose: To explore the cellular mechanisms of cobalt‐induced epileptiform discharges in mouse hippocampal slices.

Methods: Hippocampal slices were prepared from adult mice and briefly exposed to a CoCl2‐containing external solution. Population and single cell activities were examined via extracellular and whole‐cell patch recordings.

Results: Brief cobalt exposure induced spontaneous, ictal‐like discharges originating from the CA3 area. These discharges were suppressed by anticonvulsants, gap junction blockers, or by raising extracellular Ca2+, but their generation was not associated with overall hyperexcitability or impairment in GABAergic inhibition in the CA3 circuit. Electroencephalographic ictal discharges of similar waveforms were observed in behaving rats following intrahippocampal cobalt infusion.

Discussion: Mechanisms involving activity‐dependent facilitation of gap junctional communication may play a major role in cobalt‐induced epileptiform discharges.
Development of a Re‐Positionable Aortic Stent‐Valve: A Preliminary Study in Swine
Authors: HASHIMOTO MASAYUKI , KAMINOU TOSHIO , OHUCHI YASUFUMI , NAKAMURA KIYOSHI , SUGIURA KIMIHIKO , ADACHI AKIRA , KAWAI TSUYOSHI , IHAYA TAKASHI , OGAWA TOSHIHIDE
Published: August 2008

Background: Placement of aortic stent‐valves in the proper position is difficult due to the high velocity and oscillation of blood flow and anatomical characteristics. To address this problem, a re‐positionable stent‐valve was designed and examined in a preliminary animal experiment.

Methods: Protocols for this animal study were approved by the institutional Animal Care and Use Committee. An umbrella‐shaped polyurethane valve was attached at the tip of newly devised re‐positionable metallic stent. The prosthesis (re‐positionable stent‐valve) was implanted in 5 female pigs via the right carotid artery using a 10‐F introducer (Group A). As a control, the stent‐without‐valve was implanted in 4 female pigs (Group B). Efficacy of the valve was assessed by aortography and aortic pressure measurement. Animals were sacrificed 1 hour after stent‐valve implantation for macroscopic examination.

Results: The stent‐valve was successfully implanted in all pigs. In Group A, aortography showed good function of the polyurethane valve. No significant change in diastolic pressure was noted during valve testing. In Group B, aortography and aortic pressure measurement showed massive aortic regurgitation following dysfunction of the native aortic leaflets. Post‐mortem examination showed small amounts of thrombus inside the polyurethane umbrella in Group A.

Conclusion: Placement of the re‐positionable stent‐valve seems feasible and effective. However, the problem of thrombus formation inside the umbrella valve should be solved in future studies.
Joint Modeling and Analysis of Longitudinal Data with Informative Observation Times
Authors: Liang Yu , Lu Wenbin , Ying Zhiliang
Published: August 2008

Summary In analysis of longitudinal data, it is often assumed that observation times are predetermined and are the same across study subjects. Such an assumption, however, is often violated in practice. As a result, the observation times may be highly irregular. It is well known that if the sampling scheme is correlated with the outcome values, the usual statistical analysis may yield bias. In this article, we propose joint modeling and analysis of longitudinal data with possibly informative observation times via latent variables. A two‐step estimation procedure is developed for parameter estimation. We show that the resulting estimators are consistent and asymptotically normal, and that the asymptotic variance can be consistently estimated using the bootstrap method. Simulation studies and a real data analysis demonstrate that our method performs well with realistic sample sizes and is appropriate for practical use.
On Estimation of the Survivor Average Causal Effect in Observational Studies When Important Confounders Are Missing Due to Death
Authors: Egleston Brian L. , Scharfstein Daniel O. , MacKenzie Ellen
Published: August 2008

Summary We focus on estimation of the causal effect of treatment on the functional status of individuals at a fixed point in time t* after they have experienced a catastrophic event, from observational data with the following features: (i) treatment is imposed shortly after the event and is nonrandomized, (ii) individuals who survive to t* are scheduled to be interviewed, (iii) there is interview nonresponse, (iv) individuals who die prior to t* are missing information on preevent confounders, and (v) medical records are abstracted on all individuals to obtain information on postevent, pretreatment confounding factors. To address the issue of survivor bias, we seek to estimate the survivor average causal effect (SACE), the effect of treatment on functional status among the cohort of individuals who would survive to t* regardless of whether or not assigned to treatment. To estimate this effect from observational data, we need to impose untestable assumptions, which depend on the collection of all confounding factors. Because preevent information is missing on those who die prior to t*, it is unlikely that these data are missing at random. We introduce a sensitivity analysis methodology to evaluate the robustness of SACE inferences to deviations from the missing at random assumption. We apply our methodology to the evaluation of the effect of trauma center care on vitality outcomes using data from the National Study on Costs and Outcomes of Trauma Care.
Variable Selection and Model Choice in Geoadditive Regression Models
Authors: Kneib Thomas , Hothorn Torsten , Tutz Gerhard
Published: August 2008

SummaryModel choice and variable selection are issues of major concern in practical regression analyses, arising in many biometric applications such as habitat suitability analyses, where the aim is to identify the influence of potentially many environmental conditions on certain species. We describe regression models for breeding bird communities that facilitate both model choice and variable selection, by a boosting algorithm that works within a class of geoadditive regression models comprising spatial effects, nonparametric effects of continuous covariates, interaction surfaces, and varying coefficients. The major modeling components are penalized splines and their bivariate tensor product extensions. All smooth model terms are represented as the sum of a parametric component and a smooth component with one degree of freedom to obtain a fair comparison between the model terms. A generic representation of the geoadditive model allows us to devise a general boosting algorithm that automatically performs model choice and variable selection.
Calculating Sample Size for Studies with Expected All‐or‐None Nonadherence and Selection Bias
Authors: Shardell Michelle D. , El‐Kamary Samer S.
Published: August 2008

Summary We develop sample size formulas for studies aiming to test mean differences between a treatment and control group when all‐or‐none nonadherence (noncompliance) and selection bias are expected. Recent work by Fay, Halloran, and Follmann (2007, Biometrics63, 465–474) addressed the increased variances within groups defined by treatment assignment when nonadherence occurs, compared to the scenario of full adherence, under the assumption of no selection bias. In this article, we extend the authors' approach to allow selection bias in the form of systematic differences in means and variances among latent adherence subgroups. We illustrate the approach by performing sample size calculations to plan clinical trials with and without pilot adherence data. Sample size formulas and tests for normally distributed outcomes are also developed in a Web Appendix that account for uncertainty of estimates from external or internal pilot data.
Hierarchical Spatial Modeling of Additive and Dominance Genetic Variance for Large Spatial Trial Datasets
Authors: Finley Andrew O. , Banerjee Sudipto , Waldmann Patrik , Ericsson Tore
Published: August 2008

SummaryThis article expands upon recent interest in Bayesian hierarchical models in quantitative genetics by developing spatial process models for inference on additive and dominance genetic variance within the context of large spatially referenced trial datasets. Direct application of such models to large spatial datasets are, however, computationally infeasible because of cubic‐order matrix algorithms involved in estimation. The situation is even worse in Markov chain Monte Carlo (MCMC) contexts where such computations are performed for several iterations. Here, we discuss approaches that help obviate these hurdles without sacrificing the richness in modeling. For genetic effects, we demonstrate how an initial spectral decomposition of the relationship matrices negate the expensive matrix inversions required in previously proposed MCMC methods. For spatial effects, we outline two approaches for circumventing the prohibitively expensive matrix decompositions: the first leverages analytical results from Ornstein–Uhlenbeck processes that yield computationally efficient tridiagonal structures, whereas the second derives a modifiedpredictive processmodel from the original model by projecting its realizations to a lower‐dimensional subspace, thereby reducing the computational burden. We illustrate the proposed methods using a synthetic dataset with additive, dominance, genetic effects and anisotropic spatial residuals, and a large dataset from a Scots pine (Pinus sylvestrisL.) progeny study conducted in northern Sweden. Our approaches enable us to provide a comprehensive analysis of this large trial, which amply demonstrates that, in addition to violating basic assumptions of the linear model, ignoring spatial effects can result in downwardly biased measures of heritability.
Genetic Association Studies in Nursing Practice and Scholarship
Authors: Underwood Patricia C. , Read Catherine Y.
Published: August 2008

Purpose: To explore the role of genetic association studies in risk assessment for common complex diseases.

Organizing Framework: An introduction to the types of genetic association studies is followed by a discussion of their potential use in risk assessment for age‐related macular degeneration and type 2 diabetes mellitus. The benefits and limitations of this burgeoning technology are explored and related to nursing practice and scholarship.

Conclusions: Nurses in practice must be prepared to assist clients with decisions about seeking and interpreting results from genetic association studies and nurse researchers must apply current guidelines for conducting robust studies and applying the results of such studies in clinical practice.

Clinical Relevance: Data collected from genetic association studies will increasingly be used to identify novel prevention and treatment strategies for many complex diseases. An understanding of the principles that underlie this new science is essential for nurses in all areas of clinical practice as they design, test, and implement appropriate intervention and prevention strategies based on genetic association studies.
Cultural Perspectives in Feeding Difficulty in Taiwanese Elderly With Dementia
Authors: Chang Chia‐Chi , Roberts Beverly L.
Published: August 2008

Objective: To investigate factors related to feeding difficulty that is shown in the interaction between nursing assistants and elderly residents with dementia.

Methods: Forty‐eight residents and 31 nursing assistants were observed during meal times in a congregate dining room of a Taiwanese nursing home specializing in dementia care. Residents' eating behaviors, the dining environment, interactions between the nursing assistant and the residents, and feeding strategies used by nursing assistants were observed. Nutritional data for residents were collected from medical charts. The EdFED Scale #2 and interviews of nursing assistants provided information about feeding difficulty. Interviews also provided data on strategies used to address feeding difficulties.

Findings: The most frequent feeding difficulty was refusal to eat (37.5%). The strategies used by nursing assistants were limited. Nursing assistants stated they needed more training to address feeding difficulty in residents with dementia.

Conclusions: Future research should be focused on the interface between the residents and nursing assistants who must identify various feeding difficulties and select appropriate interventions.

Clinical Relevance: Results might provide information that can be used to develop effective interventions and promote high‐quality mealtime care in patients with dementia.