bluuebunny/crossref_metadata_2025_split huggingface dataset:
In Vivo Profiling of Focal Cortical Dysplasia on High‐resolution MRI with Computational Models
Authors: Colliot Olivier , Antel Samson B. , Naessens Veronique B. , Bernasconi Neda , Bernasconi Andrea 
Published: January 2006

Summary:  Purpose: On MRI, focal cortical dysplasia (FCD) is characterized by a combination of increased cortical thickness, hyperintense signal within the dysplastic lesion, and blurred transition between gray and white matter (GM–WM). The visual identification of these abnormal characteristics may be difficult, and it is unclear to what degree these features occur among different FCD lesions. Our purpose was to investigate the pattern of occurrence of abnormal MRI characteristics in FCD by using a set of computational models and to generate quantitative lesion profiling. Methods: A set of voxel‐wise operators was applied to high‐resolution 3D T1‐weighted MRI in 23 patients with histologically proven FCD and 39 healthy controls, creating maps of GM thickness, maps of relative intensity highlighting areas with hyperintense signal, and maps of gradient magnitude modeling the GM–WM transition. All FCD lesions were segmented manually on the T1‐weighted MRI. Results: FCD volumes ranged from 734 mm3 to 80,726 mm3 (mean, 8,629 mm3± 16,238). The manually segmented FCD lesions were used to estimate features in the lesional area and to determine possible local variations of each feature by means of a histogram. In 78% of the patients, FCD lesions were characterized by simultaneous GM thickening, hyperintense signal, and blurring of the GM–WM transition. Moreover, in all patients, the FCD lesion had at least two of these three characteristics. Conclusions: The three features occurred regardless of the lesion volume, and they characterized not only large FCD lesions, but also subtle ones that had been overlooked by conventional radiologic inspection before surgery.
Quantitative MRI Biomarkers of Cognitive Morbidity in Temporal Lobe Epilepsy
Authors: Oyegbile Tayo O. , Bhattacharya Abhik , Seidenberg Michael , Hermann Bruce P. 
Published: January 2006

Summary:  Purpose: To determine the relation between neuropsychological morbidity, quantitative magnetic resonance imaging (MRI) measures of whole brain structure, and clinical seizure factors reflecting epilepsy cause, course, and treatment. Methods: Quantitative MRI measurements of total (whole brain) cerebrospinal fluid (CSF) and gray‐ and white‐matter volumes and clinical seizure features were examined in relation to summary indices of cognitive morbidity in 96 patients with temporal lobe epilepsy. MRI volumes were adjusted for intracranial volume (ICV), and cognitive scores were adjusted for age, education, and gender, based on a sample of 82 healthy controls. Results: Whole‐brain volumes (gray, white, and CSF) were abnormal in chronic temporal lobe epilepsy patients compared with controls and were related significantly to neuropsychological morbidity, especially total CSF. Statistical modeling demonstrated that markers of total atrophy (CSF) was the primary mediator of the relation between clinical seizure variables and neuropsychological morbidity. Conclusions: Quantitative measurements of overall brain abnormality (atrophy) in temporal lobe epilepsy are clinically meaningful markers that are associated with increased cognitive morbidity. These biomarkers appear to mediate the adverse effects of some clinical seizure variables on cognition.
Cognitive Functions in Juvenile and Adult Patients with Gelastic Epilepsy due to Hypothalamic Hamartoma
Authors: Quiske Ansgar , Frings Lars , Wagner Kathrin , Unterrainer Josef , Schulze‐Bonhage Andreas 
Published: January 2006

Summary:  Purpose: To describe extend and severity of cognitive deficits in juvenile and adult patients with gelastic seizures and hypothalamic hamartoma (HH) and to analyze the impact of epilepsy‐related variables on cognitive performance. Methods: Thirteen juvenile and adult patients (mean age, 25 years; seven men) underwent comprehensive neuropsychological testing assessing intellectual performance, attention and executive functions, verbal and visual memory, and visuospatial abilities. Results: Intellectual abilities ranged from moderate mental retardation to good average performance; 54% of the patients displayed below‐average global intellectual abilities. Attentional and executive functions were impaired in 23% to 46% of the patients. Below‐average visuospatial capabilities were observed in 39% of the cases. Memory functions were impaired regarding both visual (77%) and verbal learning (62%). Nonparametric correlation analysis revealed a significant relation between monthly partial seizure frequency and reduced cognitive flexibility and reduced performance in mental rotation. In addition, HH volume was significantly negatively correlated with cognitive flexibility, whereas age at onset and duration of epilepsy did not show significant correlation to cognitive performance. Conclusions: More than half of the adult patients with gelastic seizures and HH displayed deficits in a broad range of cognitive functions, expressed mostly in visual and verbal learning and memory. Some of the deficits could be shown to correlate with disease‐related characteristics representing the severity of the epilepsy or the size of the underlying lesion. These findings prompt for a longitudinal investigation of the development of these cognitive deficits to analyze further the relevant factors contributing to this wide spectrum of cognitive impairments.
Somatosensory Auras in Refractory Temporal Lobe Epilepsy
Authors: Erickson Jay C. , Clapp Lawrence E. , Ford Gwendolyn , Jabbari Bahman 
Published: January 2006

Summary:  Purpose: To determine the prevalence, manifestations, lateralizing value, and surgical prognostic value of somatosensory auras (SSAs) in patients with refractory temporal lobe epilepsy (TLE). Methods: Eighty‐one consecutive patients undergoing temporal lobectomy for refractory complex‐partial seizures were screened for SSAs. The characteristics of the somatosensory phenomena, occurrence of other aura types, seizure semiology, findings of EEG and imaging studies, temporal lobe neuropathology, and postoperative seizure outcome were determined in each patient with SSAs. Results: Nine (11%) of 81 patients with refractory temporal lobe seizures reported distinct SSAs as part of their habitual seizures. The most common manifestation of SSAs was tingling (eight of nine, 89%), but sensory loss (one of nine, 11%) and pain (one of nine, 11%) also were reported. Five patients had unilateral somatosensory symptoms, and four patients had bilateral somatosensory symptoms. Seizure origin was in the contralateral temporal lobe in four (80%) of five patients with unilateral SSAs, including all patients with unilateral SSAs affecting a limb. Partial temporal lobe resection produced complete seizure remission in all nine (100%) patients 1 year after surgery and in seven (78%) of nine patients 2 years after surgery. Conclusions: SSAs occur more frequently than previously appreciated in patients with refractory temporal lobe seizures and usually manifest as either unilateral or bilateral tingling. In patients with temporal lobe seizures, unilateral SSAs involving a limb suggest a seizure origin in the contralateral temporal lobe. The surgical outcome of TLE patients with SSAs is favorable. Thus the presence of SSAs should not serve as a deterrent to temporal lobe resection in patients with clearly defined TLE.
β‐Ureidopropionase Deficiency Presenting with Febrile Status Epilepticus
Authors: Assmann Birgit E. , Van Kuilenburg Andre B. P. , Distelmaier Felix , Abeling Nico G. G. M. , Rosenbaum Thorsten , Schaper Jörg , Duran Marinus , Mayatepek Ertan 
Published: January 2006

Summary:  β‐Ureidopropionase is the third enzyme in the catabolic pathway of uracil and thymine. To date, only three other patients are reported with this inborn error of metabolism. We report the clinical presentation of a male patient who presented at the age of 4 months after an ALTE‐like event (ALTE = acute life‐threatening event) with febrile status epilepticus. Such a clinical presentation has not been reported before in this condition. Diagnosis was based on biochemical, enzymatic and molecular studies. MRI (magnetic resonance imaging) at the age of 11 months demonstrated large subdural hematomata and global supratentorial atrophy. At that time the patient showed severe psychomotor retardation with muscular hypotonia, extremely limited visual contact and poorly controlled epilepsy. Conclusions: Pyrimidine degradation defects should be included in the defferential diagnosis of convulsions, (febrile) status epilepticus, psychomotor retardation and possibly also ALTE‐like events.
An Examination of the Differential Impact of Regulation FD on Analysts' Forecast Accuracy
Authors: Findlay Scott , Mathew Prem G. 
Published: January 2006

AbstractRegulation fair disclosure (FD) requires companies to publicly disseminate information, effectively preventing the selective pre‐earnings announcement guidance to analysts common in the past. We investigate the effects of Regulation FD's reducing information disparity across analysts on their forecast accuracy. Proxies for private information, including brokerage size and analyst company‐specific experience, lose their explanatory power for analysts' relative accuracy after Regulation FD. Analyst forecast accuracy declines overall, but analysts that are relatively less accurate (more accurate) before Regulation FD improve (deteriorate) after implementation. Our findings are consistent with selective guidance partially explaining variation in the forecasting accuracy of analysts before Regulation FD.
Uncertain Demand, Heterogeneous Expectations, and Unintentional IPO Underpricing
Authors: Gouldey Bruce K. 
Published: January 2006

AbstractDistinguishing between intentional and unintentional incentives to underprice initial public offerings (IPOs), I develop sufficient conditions for the winners' curse postulated by Miller (1977) and implications for intertemporal changes in the magnitude of underpricing. Specifically, I show that unintentional underpricing (and occasional overpricing) of IPOs is a consequence of investors' heterogeneous expectations of the uncertain value of a stock when the supply is constrained and the underwriter's price discovery process only partially identifies aggregate demand. Moreover, an IPO that is oversubscribed in the premarket sale almost certainly will experience a short‐term price increase in the secondary market.
Variance Spillover and Skewness in Financial Asset Returns
Authors: Korkie Bob , Sivakumar Ranjini , Turtle Harry J. 
Published: January 2006

AbstractBond and stock returns have been observed in the literature to exhibit unconditional skewness and temporal persistence in conditional skewness. We demonstrate that observed persistence in conditional third central moments can be due to the spillover of conditional variance dynamics. The confounding of true skewness and a variance spillover effect is problematic for financial modeling. Using market data, we empirically demonstrate that a simple standardization approach removes the variance‐induced skewness persistence. An important implication is that more parsimonious return and asset pricing models result if skewness persistence need not be modeled.
The Effect of Negotiation Practices on the Relationship between Suppliers and Customers
Authors: Atkin Thomas S. , Rinehart Lloyd M. 
Published: January 2006

This article examines the effects of negotiation practices, such as coercion and contract formality, on how suppliers and customers perceived the resulting business relationship. We conducted a purchasing negotiation simulation with students in a classroom setting in which participants competed for resources in a mock supply‐chain context. The participants were surveyed at key stages of the ongoing negotiation in order to measure their behaviors as a customer–supplier relationship developed. The data were used to test several hypotheses developed from the marketing and purchasing literature. The hypotheses were analyzed using structural equation modeling.Results demonstrated that the use of coercive techniques by negotiators during negotiation had a negative effect on satisfaction. In addition, the findings showed that, as expected, negotiators entering a negotiation with a cooperative orientation would tend to avoid the use of coercive practices during negotiation. The cooperative orientation also exhibited an unexpected positive effect on the formalization of the design of the contract between the parties. This study contributes to the current knowledge base focusing on the creation of agreements between companies and will, we hope, encourage the integration of suppliers and customers in an operating context within a supply‐chain setting.
THE IMPACT OF HIV/AIDS MORBIDITY AND MORTALITY ON HOUSEHOLDS – A REVIEW OF HOUSEHOLD STUDIES
Authors: NAIDU VENI , HARRIS GEOFF 
Published: January 2006

AbstractThirty two studies of the impact of HIV/AIDS on households conducted over the last decade were reviewed. The direct and indirect costs of HIV/AIDS to households increase with severity of illness and ultimately death. HIV/AIDS morbidity and mortality affect household income and expenditure patterns. Households employ various survival strategies to alleviate loss of labour and income, survive the financial cost and optimise the use of safety networks. Various gaps were found in the literature, which future studies could explore. Household surveys should be multi‐disciplinary and longitudinal in nature so that the full impact of HIV/AIDS could be assessed over time.
THE ROLE OF SOCIAL GRANTS IN MITIGATING THE SOCIO‐ECONOMIC IMPACT OF HIV/AIDS IN TWO FREE STATE COMMUNITIES1
Authors: BOOYSEN FRIKKIE , VAN DER BERG SERVAAS 
Published: January 2006

AbstractSocial grants may play an important role in mitigating the impact of HIV/AIDS. Eligibility for these grants is driven in part by the increasing burden of chronic illness, the mounting orphan crisis and the impoverishment of households associated with the epidemic. This article investigates the role of social grants in mitigating the socio‐economic impact of HIV/AIDS in South Africa, using data from a panel study on the household impact of the epidemic. Social grants reduce inequality and decrease the prevalence, depth and severity of poverty in affected households. However, these transfers also have disincentive effects on employment, while non‐uptake is in some cases higher amongst the poorest.
EDUCATION OUTCOMES AND HOUSEHOLD ILLNESS AND DEATH IN THE SOUTH AFRICAN SCHOOL SETTING
Authors: SCHIERHOUT G.H. 
Published: January 2006

AbstractIt is widely recognized that the HIV/AIDS epidemic may significantly disadvantage children's education in severely affected countries, but empirical quantitative data demonstrating effects and children at risk are scant. The main objective of this study was to investigate associations between chronic illness and death in the household and select educational outcomes in a school setting. This study provides information on the extent of household illness and death in schools in two provinces in South Africa and explores the relationship between these events and select educational measures. Based on the study findings, we present some of the challenges facing the education sector with regards to managing and monitoring the impacts of illness and death, including HIV and AIDS on education at school level.
WILL SMALL AND MEDIUM ENTERPRISES PROVIDE HIV/AIDS SERVICES TO EMPLOYEES? AN ANALYSIS OF MARKET DEMAND
Authors: CONNELLY P. , ROSEN S. 
Published: January 2006

AbstractBackground: Although many large businesses have begun offering HIV/AIDS prevention and treatment services to employees, the vast majority of small and medium sized enterprises (SMEs) have not. SMEs face constraints reducing their demand for services. This study identifies and evaluates those constraints to determine the extent to which SMEs can be expected to implement HIV/AIDS programmes, and to identify opportunities for strengthening the role of SMEs in South Africa's response to the epidemic.Methods: Structured interviews were conducted with a random sample of 80 SMEs located in KwaZulu Natal (KZN) and Gauteng provinces.Results: About one quarter of the companies sampled provided some HIV/AIDS services to employees and fewer than half incurred any direct costs to provide those services. Although 52 per cent of the companies believed they had lost employees to AIDS, few of those employees were regarded as critical to operations. AIDS accounted for 10 per cent of the overall annual employee turnover of 13 per cent. Few companies incur direct costs in recruiting or training, and just 30 per cent of permanent employees have access to employer sponsored healthcare. HIV/AIDS ranked 9th of 10 major business concerns faced by SMEs.Conclusions: Since managers believe few employees are leaving the workforce due to HIV/AIDS and SMEs appear to incur few costs to replace workers, managers are relatively unconcerned about HIV/AIDS. Serious demand‐side barriers exist in the market for HIV/AIDS services for SMEs. For most of the SMEs in our survey, the constraints are too great to expect SMEs to play a major role in the national response to AIDS without assistance.
Cryptococcus neoformans
Senses CO
2
through the Carbonic Anhydrase Can2 and the Adenylyl Cyclase Cac1
Authors: Mogensen Estelle Gewiss , Janbon Guilhem , Chaloupka James , Steegborn Clemens , Fu Man Shun , Moyrand Frédérique , Klengel Torsten , Pearson David S. , Geeves Michael A. , Buck Jochen , Levin Lonny R. , Mühlschlegel Fritz A. 
Published: January 2006

ABSTRACT

Cryptococcus neoformans
, a fungal pathogen of humans, causes fatal meningitis in immunocompromised patients. Its virulence is mainly determined by the elaboration of a polysaccharide capsule surrounding its cell wall. During its life,
C. neoformans
is confronted with and responds to dramatic variations in CO
2
concentrations; one important morphological change triggered by the shift from its natural habitat (0.033% CO
2
) to infected hosts (5% CO
2
) is the induction of capsule biosynthesis. In cells, CO
2
is hydrated to bicarbonate in a spontaneous reaction that is accelerated by carbonic anhydrases. Here we show that
C. neoformans
contains two β-class carbonic anhydrases, Can1 and Can2. We further demonstrate that
CAN2
, but not
CAN1
, is abundantly expressed and essential for the growth of
C. neoformans
in its natural environment, where CO
2
concentrations are limiting. Structural studies reveal that Can2 forms a homodimer in solution. Our data reveal Can2 to be the main carbonic anhydrase and suggest a physiological role for bicarbonate during
C. neoformans
growth. Bicarbonate directly activates the
C. neoformans
Cac1 adenylyl cyclase required for capsule synthesis. We show that this specific activation is optimal at physiological pH.
The Arf-GTPase-Activating Protein Gcs1p Is Essential for Sporulation and Regulates the Phospholipase D Spo14p
Authors: Connolly Jaime E. , Engebrecht JoAnne 
Published: January 2006

ABSTRACT

SPO14
, encoding the major
Saccharomyces cerevisiae
phospholipase D (PLD), is essential for sporulation and mediates synthesis of the new membrane that encompasses the haploid nuclei that arise through meiotic divisions. PLD catalyzes the hydrolysis of phosphatidylcholine to phosphatidic acid (PA) and choline. PA stimulates Arf-GTPase-activating proteins (Arf-GAPs), which are involved in membrane trafficking events and actin cytoskeletal function. To determine if Spo14p-generated PA mediates its biological response through Arf-GAPs, we analyzed the sporulation efficiencies of cells deleted for each of the five known and potential yeast Arf-GAPs. Only
gcs1Δ
mutants display a sporulation defect similar to that of
spo14
mutants: cells deleted for
GCS1
initiate the sporulation program but are defective in synthesis of the prospore membrane. Endosome-to-vacuole transport is also impaired in
gcs1Δ
cells during sporulation. Furthermore, Arf-GAP catalytic activity, but not the pleckstrin homology domain, is required for both prospore membrane formation and endosome-to-vacuole trafficking. An examination of Gcs1p-green fluorescent protein revealed that it is a soluble protein. Interestingly, cells deleted for
GCS1
have reduced levels of Spo14p-generated PA. Taken together, these results indicate that
GCS1
is essential for sporulation and suggest that
GCS1
positively regulates
SPO14
.
Serum Resistance-Associated Protein Blocks Lysosomal Targeting of Trypanosome Lytic Factor in
Trypanosoma brucei
Authors: Oli Monika W. , Cotlin Laura F. , Shiflett April M. , Hajduk Stephen L. 
Published: January 2006

ABSTRACT

Trypanosoma brucei brucei
is the causative agent of nagana in cattle and can infect a wide range of mammals but is unable to infect humans because it is susceptible to the innate cytotoxic activity of normal human serum. A minor subfraction of human high-density lipoprotein (HDL) containing apolipoprotein A-I (apoA-I), apolipoprotein L-I (apoL-I), and haptoglobin-related protein (Hpr) provides this innate protection against
T. b. brucei
infection. This HDL subfraction, called trypanosome lytic factor (TLF), kills
T. b. brucei
following receptor binding, endocytosis, and lysosomal localization.
Trypanosoma brucei rhodesiense
, which is morphologically and physiologically indistinguishable from
T. b. brucei
, is resistant to TLF-mediated killing and causes human African sleeping sickness. Human infectivity by
T. b. rhodesiense
correlates with the evolution of a resistance-associated protein (SRA) that is able to ablate TLF killing. To examine the mechanism of TLF resistance, we transfected
T. b. brucei
with an epitope-tagged
SRA
gene. Transfected
T. b. brucei
expressed SRA mRNA at levels comparable to those in
T. b. rhodesiense
and was highly resistant to TLF. In the SRA-transfected cells, intracellular trafficking of TLF was altered, with TLF being mainly localized to a subset of SRA-containing cytoplasmic vesicles but not to the lysosome. These results indicate that the cellular distribution of TLF is influenced by SRA expression and may directly determine the organism's susceptibility to TLF.
Candida albicans
Ecm33p Is Important for Normal Cell Wall Architecture and Interactions with Host Cells
Authors: Martinez-Lopez Raquel , Park Hyunsook , Myers Carter L. , Gil Concha , Filler Scott G. 
Published: January 2006

ABSTRACT

Candida albicans ECM33
encodes a glycosylphosphatidylinositol-linked cell wall protein that is important for cell wall integrity. It is also critical for normal virulence in the mouse model of hematogenously disseminated candidiasis. To identify potential mechanisms through which Ecm33p contributes to virulence, we investigated the interactions of
C. albicans ecm33
Δ mutants with endothelial cells and the FaDu oral epithelial cell line in vitro. The growth rate of blastospores of strains containing either one or no intact copies of
ECM33
was 50% slower than that of strains containing two intact copies of
ECM33
. However, all strains germinated at the same rate, forming similar-length hyphae on endothelial cells and oral epithelial cells. Strains containing either one or no intact copies of
ECM33
had modestly reduced adherence to both types of host cells, and a markedly reduced capacity to invade and damage these cells.
Saccharomyces cerevisiae
expressing
C. albicans ECM33
did not adhere to or invade epithelial cells, suggesting that Ecm33p by itself does not act as an adhesin or invasin. Examination of
ecm33
Δ mutants by transmission electron microscopy revealed that the cell wall of these strains had an abnormally electron-dense outer mannoprotein layer, which may represent a compensatory response to reduced cell wall integrity. The hyphae of these mutants also had aberrant surface localization of the adhesin Als1p. Collectively, these results suggest that Ecm33p is required for normal cell wall architecture as well as normal function and expression of cell surface proteins in
C. albicans
.