bluuebunny/crossref_metadata_2025 huggingface dataset:
Predicting Turnover of Appointed County Managers in Large American Counties
Authors: Tekniepe Robert J. , Stream Christopher
Published: December 2009

Researchers have suggested that American counties are emerging as leaders in local governance. This is mainly attributed to counties being called on to provide a whole host of new services to an ever-growing population. County managers are known to play a critical role in the provision of these services. Thus, the extent of turnover among county managers can significantly affect the services provided to a community. To date, researchers know very little about the factors contributing to county manager turnover. Several empirical analyses have explored tenure and turnover patterns of top-level government executives, yet these analyses have principally focused on cities. The purpose of this article is to extend existing research on city and county manager turnover. In this study, the authors test hypotheses with data on county manager turnover from 32 large counties with populations greater than 500,000 over a period of 15 years (1992-2006). As with prior studies performed on city manager turnover, the authors posit that county manager turnover in counties with a commission—manager form of government are influenced by forces of political uncertainty, fiscal stress, and community instability. The results show that increases in measurements of political uncertainty, fiscal stress, and community instability positively influence county manager turnover. Furthermore, the results show that increases in a county manager’s level of formal education increase the odds that a county manager will remain in office. Similar increases were found when county managers who were promoted from within the organization were compared with those who were recruited from external sources.
Epoxy/Multiwall Carbon Nanotube Nanocomposites Prepared By Sonication and Planetary Mixing Technique
Authors: Wen Shyang Chow  , Pi Lin Tan
Published: December 2009

Epoxy/multiwall carbon nanotube (MWNT) composites were prepared using two different mixing techniques (i.e., sonication and planetary mixing) followed by curing. Different concentrations (0.25-1.25 wt%) of MWNT were incorporated into the epoxy. The mechanical properties of the epoxy/MWNT nanocomposites were characterized using three-point bending flexural and fracture toughness tests. The morphology of the epoxy nanocomposites was investigated using field-emission scanning electron microscopy (FESEM). It was found that the mechanical properties (e.g., flexural modulus, flexural yield stress, and fracture toughness) of the epoxy nanocomposites were controlled by different concentrations of MWNT and mixing techniques (i.e., sonication and planetary mixing). The enhancement of modulus and stiffness of the epoxy could be associated with the good dispersion and reinforcing efficiency of the MWNT. FESEM micrograph evidenced that the epoxy nanocomposites prepared using sonication showed better MWNT dispersion compared with the epoxy nanocomposites prepared using planetary mixing.
Cognitive Performance in Nondemented Nonpsychotic Parkinson Disease Patients With or Without a History of Depression Prior to the Onset of Motor Symptoms
Authors: Klepac Nataša , Hajnšek Sanja , Trkulja Vladimir
Published: December 2009

In Parkinson disease (PD), cognitive impairment is common, occurs mainly in the form of milder deficits (as opposed to dementia), and commonly coincides with depression. In this cross-sectional study, we evaluated whether depression that existed before the onset of typical motor symptoms (pre-PD depression) reflected on the actual cognitive performance. Nondemented nonpsychotic PD patients with (test, n = 27) and without (control, n = 112) a history of pre-PD depression, caliper-matched for age, education, and disease duration were assessed for motor and nonmotor disease characteristics and in a battery of cognitive tests. Test patients had higher actual depression/anxiety levels. Gradual multivariate and mediation analysis indicated unfavorable effects of pre-PD depression on cognition: a direct effect on mental set shifting/response inhibition (independent of actual depression/ anxiety or other factors); and indirect effects on other cognitive domains mediated through the increased depression/anxiety. Data suggest that pre-PD depression favors poorer cognitive abilities in nondemented patients at a given time after PD has been diagnosed.
Minding Motherhood and the Burden of an Ancient Blessing: “May You Be the Mother of a Hundred Sons”
Authors: Moitra Goel Koeli
Published: December 2009

This performance is crafted within the narrow space of the author’s existence as a human, as a person, as a female, and as a mother. The rich, intricate experience of a life lived out as a mother of Indian origin, configured out of many years of negotiation between each of these identities becomes the fertile ground for articulation on overarching questions about the representation of motherhood, the problematics, polemics, and politics surrounding it.
Theorizing the client—consultant relationship from the perspective of social-systems theory
Authors: Mohe Michael , Seidl David
Published: December 2009

Over the last few years research on management consulting has established itself as an important area in management studies. While, traditionally, consulting research has been predominantly a-theoretical, lately researchers have been calling for an exploration of different theoretical approaches. This article has been written in response to these calls. It explores a new perspective for theorizing the client—consultant relationship based on the theory of social systems by Niklas Luhmann. According to this approach, clients and consultants can be conceptualized as two autopoietic communication systems that operate according to idiosyncratic logics. They are structurally coupled through a third system, the so-called ‘contact system’. Due to the different logics of these systems, the transfer of meaning between them is not possible. This theoretical position has interesting implications for the way we conceptualize consulting, challenging many traditional assumptions. Instead of supporting the client in finding solutions to their problems, this perspective emphasizes that consulting firms can only cause ‘perturbations’ in the client’s communication processes, inducing the client system to construct its own meaning from it.
Power and Social Work in the United Kingdom
Authors: Gilbert Tony , Powell Jason L.
Published: December 2009

• Summary: This article explores relations of power in social work using insights drawn from the critical ‘toolkit’ emanating from work of French philosopher, Michel Foucault. The article discusses the relationship between Foucault’s conceptual tools of ‘knowledge and power’, the emergence of ‘the modern subject’ and the concept of ‘governmentality’. Despite ongoing pressures, professional expertise persists as a core element of neo-liberal government in the management of the population. We use a Foucauldian perspective to explore two issues central to contemporary practice: surveillance and discretion that epitomise dualism of power relations. On the one hand, surveillance brings with it a potentially problematic process especially in context of top down managerial power; yet, on the other hand, discretion is much more focused on what Foucault (1977) calls ‘the microphysics of power’ with opportunities for ‘resistance’ from the bottom up.

• Findings: Professional expertise creates a paradox where surveillance and discretion operate within similar social space as the expression of power relations that encompass the matrix of users, carers and social workers. On one hand, surveillance restricts practice however; on the other, complexity opens the space for resistance and new formulations of power relations.

• Applications : Exposing social work activity to a critical stance enables the exploration of relations of power identifying how commitments such as empowerment and anti-oppressive practice become detached from their original radical and humanitarian moorings to feature now as components of oppressive discourses they might once have challenged.
Socialization Factors Conducive to Social Work Students’ Gain in Competence
Authors: Cheung Chau-Kiu , Tang Kwong-Leung
Published: December 2009

• Summary: Socialization experiences related to background and secondary education are likely to affect academic achievement in university education, according to extant theory and research. How these experiences affect Hong Kong social work students’ grade-point-average (GPA) and self-assessed gain in competence in social work is the focus of examination in the present study. It is argued that among the experiences, that of volunteering during secondary school is likely to benefit the student, because of value congruence between volunteering and social work education.

• Findings: This effect bears out in a survey of social work undergraduates in Hong Kong. Another important finding is the absence of privilege accruing from the socioeconomic status of students’ parents. In contrast, some indicators of the status negatively affected the students’ grade-point-averages.

• Applications : These findings favor the use of the applicant’s volunteering experience as an admission criterion for the social work education program in university.
Children Exposed to Domestic Violence
Authors: Øverlien Carolina
Published: December 2009

• Summary: This article examines and discusses the research field of children exposed to domestic violence, a field which has greatly expanded during the last 10 years. The author presents an overview of this research, discusses its implications, and describes future challenges and contemporary knowledge gaps.

• Findings: The author argues that the field is dominated by studies that a) are quantitative, b) use the mothers as the informant and c) are represented by traditional psychology and social medicine, rather than social work. These studies have found substantial support for the negative emotional and behavioral consequences that children exposed to domestic violence suffer. However, many questions and problems remain unanswered. These questions include both the research field itself and the need for new approaches such as qualitative research including the voice of the child, longitudinal studies, and questions regarding methodology and research ethics.

• Applications : The author argues that there is a need for more qualitative research in general and social work research in particular. The implications for social work practice and policy are discussed.
Efficacy of deferasirox in reducing and preventing cardiac iron overload in β-thalassemia
Authors: Pennell Dudley J. , Porter John B. , Cappellini Maria Domenica , El-Beshlawy Amal , Chan Lee Lee , Aydinok Yesim , Elalfy Mohsen Saleh , Sutcharitchan Pranee , Li Chi-Kong , Ibrahim Hishamshah , Viprakasit Vip , Kattamis Antonis , Smith Gillian , Habr Dany , Domokos Gabor , Roubert Bernard , Taher Ali
Published: December 2009

Cardiac iron overload causes most deaths in β-thalassemia major. The efficacy of deferasirox in reducing or preventing cardiac iron overload was assessed in 192 patients with β-thalassemia in a 1-year prospective, multicenter study. The cardiac iron reduction arm (n = 114) included patients with magnetic resonance myocardial T2* from 5 to 20 ms (indicating cardiac siderosis), left ventricular ejection fraction (LVEF) of 56% or more, serum ferritin more than 2500 ng/mL, liver iron concentration more than 10 mg Fe/g dry weight, and more than 50 transfused blood units. The prevention arm (n = 78) included otherwise eligible patients whose myocardial T2* was 20 ms or more. The primary end point was the change in myocardial T2* at 1 year. In the cardiac iron reduction arm, the mean deferasirox dose was 32.6 mg/kg per day. Myocardial T2* (geometric mean ± coefficient of variation) improved from a baseline of 11.2 ms (± 40.5%) to 12.9 ms (± 49.5%) (+16%; P < .001). LVEF (mean ± SD) was unchanged: 67.4 (± 5.7%) to 67.0 (± 6.0%) (−0.3%; P = .53). In the prevention arm, baseline myocardial T2* was unchanged from baseline of 32.0 ms (± 25.6%) to 32.5 ms (± 25.1%) (+2%; P = .57) and LVEF increased from baseline 67.7 (± 4.7%) to 69.6 (± 4.5%) (+1.8%; P < .001). This prospective study shows that deferasirox is effective in removing and preventing myocardial iron accumulation. This study is registered at http://clinicaltrials.gov as NCT00171821.
Fluorinated per-acetylated GalNAc metabolically alters glycan structures on leukocyte PSGL-1 and reduces cell binding to selectins
Authors: Marathe Dhananjay D. , Buffone Alexander , Chandrasekaran E. V. , Xue Jun , Locke Robert D. , Nasirikenari Mehrab , Lau Joseph T. Y. , Matta Khushi L. , Neelamegham Sriram
Published: December 2009

Novel strategies to control the binding of adhesion molecules belonging to the selectin family are required for the treatment of inflammatory diseases. We tested the possibility that synthetic monosaccharide analogs can compete with naturally occurring sugars to alter the O-glycan content on human leukocyte cell surface selectin-ligand, P-selectin glycoprotein ligand-1 (PSGL-1). Resulting reduction in the sialyl Lewis-X–bearing epitopes on this ligand may reduce cell adhesion. Consistent with this hypothesis, 50μM per-acetylated 4F-GalNAc added to the growth media of promyelocytic HL-60 cells reduced the expression of the cutaneous lymphocyte associated-antigen (HECA-452 epitope) by 82% within 2 cell doubling cycles. Cell binding to all 3 selectins (L-, E-, and P-selectin) was reduced in vitro. 4F-GalNAc was metabolically incorporated into PSGL-1, and this was accompanied by an approximately 20% reduction in PSGL-1 glycan content. A 70% to 85% reduction in HECA-452 binding epitope and N-acetyl lactosamine content in PSGL-1 was also noted on 4F-GalNAc addition. Intravenous 4F-GalNAc infusion reduced leukocyte migration to the peritoneum in a murine model of thioglycolate-induced peritonitis. Thus, the compound has pharmacologic activity. Overall, the data suggest that 4F-GalNAc may be applied as a metabolic inhibitor to reduce O-linked glycosylation, sialyl Lewis-X formation, and leukocyte adhesion via the selectins.
Single-cell analysis of the common lymphoid progenitor compartment reveals functional and molecular heterogeneity
Authors: Mansson Robert , Zandi Sasan , Welinder Eva , Tsapogas Panagiotis , Sakaguchi Nobuo , Bryder David , Sigvardsson Mikael
Published: December 2009

To investigate molecular events involved in the regulation of lymphoid lineage commitment, we crossed λ5 reporter transgenic mice to Rag1-GFP knockin mice. This allowed us to subfractionate common lymphoid progenitors and pre-pro-B (fraction A) cells into λ5−Rag1low, λ5−Rag1high, and λ5+Rag1high cells. Clonal in vitro differentiation analysis demonstrated that Rag1low cells gave rise to B/T and NK cells. Rag1high cells displayed reduced NK-cell potential with preserved capacity to generate B- and T-lineage cells, whereas the λ5+ cells were B-lineage restricted. Ebf1 and Pax5 expression was largely confined to the Rag1high populations. These cells also expressed a higher level of the surface protein LY6D, providing an additional tool for the analysis of early lymphoid development. These data suggest that the classic common lymphoid progenitor compartment composes a mixture of cells with relatively restricted lineage potentials, thus opening new possibilities to investigate early hematopoiesis.
RNRdb, a curated database of the universal enzyme family ribonucleotide reductase, reveals a high level of misannotation in sequences deposited to Genbank
Authors: Lundin Daniel , Torrents Eduard , Poole Anthony M , Sjöberg Britt-Marie
Published: December 2009

Background

Ribonucleotide reductases (RNRs) catalyse the only known de novo pathway for deoxyribonucleotide synthesis, and are therefore essential to DNA-based life. While ribonucleotide reduction has a single evolutionary origin, significant differences between RNRs nevertheless exist, notably in cofactor requirements, subunit composition and allosteric regulation. These differences result in distinct operational constraints (anaerobicity, iron/oxygen dependence and cobalamin dependence), and form the basis for the classification of RNRs into three classes.

Description

In RNRdb (Ribonucleotide Reductase database), we have collated and curated all known RNR protein sequences with the aim of providing a resource for exploration of RNR diversity and distribution. By comparing expert manual annotations with annotations stored in Genbank, we find that significant inaccuracies exist in larger databases. To our surprise, only 23% of protein sequences included in RNRdb are correctly annotated across the key attributes of class, role and function, with 17% being incorrectly annotated across all three categories. This illustrates the utility of specialist databases for applications where a high degree of annotation accuracy may be important. The database houses information on annotation, distribution and diversity of RNRs, and links to solved RNR structures, and can be searched through a BLAST interface. RNRdb is accessible through a public web interface at http://rnrdb.molbio.su.se.

Conclusion

RNRdb is a specialist database that provides a reliable annotation and classification resource for RNR proteins, as well as a tool to explore distribution patterns of RNR classes. The recent expansion in available genome sequence data have provided us with a picture of RNR distribution that is more complex than believed only a few years ago; our database indicates that RNRs of all three classes are found across all three cellular domains. Moreover, we find a number of organisms that encode all three classes.
Divergent effects of norepinephrine, dopamine and substance P on the activation, differentiation and effector functions of human cytotoxic T lymphocytes
Authors: Strell Carina , Sievers Anne , Bastian Philipp , Lang Kerstin , Niggemann Bernd , Zänker Kurt S , Entschladen Frank
Published: December 2009

Background

Neurotransmitters are important regulators of the immune system, with very distinct and varying effects on different leukocyte subsets. So far little is known about the impact of signals mediated by neurotransmitters on the function of CD8+T lymphocytes. Therefore, we investigated the influence of norepinephrine, dopamine and substance P on the key tasks of CD8+T lymphocytes: activation, migration, extravasation and cytotoxicity.

Results

The activation of naïve CD8+T lymphocytes by CD3/CD28 cross-linking was inhibited by norepinephrine and dopamine, which was caused by a downregulation of interleukin (IL)-2 expressionviaErk1/2 and NF-κB inhibition. Furthermore, all of the investigated neurotransmitters increased the spontaneous migratory activity of naïve CD8+T lymphocytes with dopamine being the strongest inducer. In contrast, activated CD8+T lymphocytes showed a reduced migratory activity in the presence of norepinephrine and substance P. With regard to extravasation we found norepinephrine to induce adhesion of activated CD8+T cells: norepinephrine increased the interleukin-8 release from endothelium, which in turn had effect on the activated CXCR1+CD8+T cells. At last, release of cytotoxic granules from activated cells in response to CD3 cross-linking was not influenced by any of the investigated neurotransmitters, as we have analyzed by measuring the β-hexosamidase release.

Conclusion

Neurotransmitters are specific modulators of CD8+T lymphocytes not by inducing any new functions, but by fine-tuning their key tasks. The effect can be either stimulatory or suppressive depending on the activation status of the cells.
Ascorbate metabolism and the developmental demand for tartaric and oxalic acids in ripening grape berries
Authors: Melino Vanessa J , Soole Kathleen L , Ford Christopher M
Published: December 2009

Background

Fresh fruits are well accepted as a good source of the dietary antioxidant ascorbic acid (Asc, Vitamin C). However, fruits such as grapes do not accumulate exceptionally high quantities of Asc. Grapes, unlike most other cultivated fruits do however use Asc as a precursor for the synthesis of both oxalic (OA) and tartaric acids (TA). TA is a commercially important product in the wine industry and due to its acidifying effect on crushed juice it can influence the organoleptic properties of the wine. Despite the interest in Asc accumulation in fruits, little is known about the mechanisms whereby Asc concentration is regulated. The purpose of this study was to gain insights into Asc metabolism in wine grapes (Vitis viniferac.v. Shiraz.) and thus ascertain whether the developmental demand for TA and OA synthesis influences Asc accumulation in the berry.

Results

We provide evidence for developmentally differentiated up-regulation of Asc biosynthetic pathways and subsequent fluctuations in Asc, TA and OA accumulation. Rapid accumulation of Asc and a low Asc to dehydroascorbate (DHA) ratio in young berries was co-ordinated with up-regulation of three of the primary Asc biosynthetic (Smirnoff-Wheeler) pathway genes. Immature berries synthesised Ascin-situfrom the primary pathway precursorsD-mannose andL-galactose. Immature berries also accumulated TA in early berry development in co-ordination with up-regulation of a TA biosynthetic gene. In contrast, ripe berries have up-regulated expression of the alternative Asc biosynthetic pathway geneD-galacturonic acid reductase with only residual expression of Smirnoff-Wheeler Asc biosynthetic pathway genes and of the TA biosynthetic gene. The ripening phase was further associated with up-regulation of Asc recycling genes, a secondary phase of increased accumulation of Asc and an increase in the Asc to DHA ratio.

Conclusion

We demonstrate strong developmental regulation of Asc biosynthetic, recycling and catabolic genes in grape berries. Integration of the transcript, radiotracer and metabolite data demonstrates that Asc and TA metabolism are developmentally regulated in grapevines; resulting in low accumulated levels of the biosynthetic intermediate Asc, and high accumulated levels of the metabolic end-product TA.
Evaluation of early coronary graft patency after coronary artery bypass graft surgery using multislice computed tomography angiography
Authors: Bassri Hosseinali , Salari Farzad , Noohi Fereidoun , Motevali Marzieh , Abdi Seifollah , Givtaj Nader , Raissi Kamal , Haghjoo Majid
Published: December 2009

Background

Coronary artery bypass graft (CABG) surgery is the standard of care in the treatment of advanced coronary artery disease, and its long-term results are affected by the failure of bypass grafts. The aim of the present study was to evaluate the early patency rate in coronary bypass grafts.

Methods

A total of 107 consecutive patients who underwent CABG were included in this study. Early graft patency was evaluated via computed tomography (CT) angiography in the first week after surgery.

Results

There were a total of 366 grafts, comprised of 250 venous grafts and 116 arterial grafts. Multi-slice CT detected acute graft occlusions in 32 (8.7%) of all the grafts, including 26 (10%) of the 250 venous grafts and 6 (5%) of the 116 arterial grafts. The patency rates obtained were 97.3% for the left internal mammary (IMA) grafts, 50% for the radial artery grafts, and 50% for the right IMA grafts. Additionally, 107 (96.4%) grafts to the left anterior descending artery (LAD) were classified as patent, whereas 1 (30%) of the 3 grafts in the left circumflex (LCX) region and 1 (50%) of the 2 grafts in the right coronary artery (RCA) territory were found to be occluded. In the venous category, 8 (13.7%) of the 58 grafts to LAD were found to be occluded. In the LCX region, 9 (8.5%) of the 106 grafts were classified as occluded, while the remaining 97 (91.5%) grafts were patent. The venous grafts to RCA were occluded in 9 (10.4%) of the 86 grafts. Amongst the multiple preoperative, intraoperative, and postoperative factors, pump time was significantly longer in the patients with occluded grafts than in those with patent grafts (P = 0.04).

Conclusion

The IMA grafts had the highest early patency rate amongst the coronary bypass grafts. However, the other arterial grafts were associated with a high rate of acute occlusions.
DYRK1A genetic variants are not linked to Alzheimer's disease in a Spanish case-control cohort
Authors: Vázquez-Higuera José Luis , Sánchez-Juan Pascual , Rodríguez-Rodríguez Eloy , Mateo Ignacio , Pozueta Ana , Frank Ana , Sastre Isabel , Valdivieso Fernando , Berciano José , Bullido María J , Combarros Onofre
Published: December 2009

Background

As dual-specificity tyrosine phosphorylation-regulated kinase 1A (DYRK1A) has been implicated in the abnormal hyperphosphorylation of tau in Alzheimer's disease (AD) brain, and the development of neurofibrillary tangles, we examined the contribution of this gene to the susceptibility for AD.

Methods

We examined genetic variations of DYRK1A by genotyping haplotype tagging SNPs (htSNPs) (rs11701483, rs2835740, rs1137600, rs2835761, rs2835762, rs2154545 and rs8132976) in a group of 634 Spanish AD cases and 733 controls.

Results

There were no differences in the genotypic, allelic or haplotypic distributions between cases and controls in the overall analysis or after stratification by APOE ε4 allele.

Conclusion

Our negative findings in the Spanish population argue against the hypothesis that DYRK1A genetic variations are causally related to AD risk. Still, additional studies using different sets of patients and control subjects deserve further attention, since supporting evidence for association between DYRK1A gene and AD risk in the Japanese population exists.
Prospective study on the mismatch concept in acute stroke patients within the first 24 h after symptom onset - 1000Plus study
Authors: Hotter Benjamin , Pittl Sandra , Ebinger Martin , Oepen Gabriele , Jegzentis Kati , Kudo Kohsuke , Rozanski Michal , Schmidt Wolf U , Brunecker Peter , Xu Chao , Martus Peter , Endres Matthias , Jungehülsing Gerhard J , Villringer Arno , Fiebach Jochen B
Published: December 2009

Background

The mismatch between diffusion weighted imaging (DWI) lesion and perfusion imaging (PI) deficit volumes has been used as a surrogate of ischemic penumbra. This pathophysiology-orientated patient selection criterion for acute stroke treatment may have the potential to replace a fixed time window. Two recent trials - DEFUSE and EPITHET - investigated the mismatch concept in a multicenter prospective approach. Both studies randomized highly selected patients (n = 74/n = 100) and therefore confirmation in a large consecutive cohort is desirable. We here present a single-center approach with a 3T MR tomograph next door to the stroke unit, serving as a bridge from the ER to the stroke unit to screen all TIA and stroke patients. Our primary hypothesis is that the prognostic value of the mismatch concept is depending on the vessel status. Primary endpoint of the study is infarct growth determined by imaging, secondary endpoints are neurological deficit on day 5-7 and functional outcome after 3 months.

Methods and design

1000Plus is a prospective, single centre observational study with 1200 patients to be recruited. All patients admitted to the ER with the clinical diagnosis of an acute cerebrovascular event within 24 hours after symptom onset are screened. Examinations are performed on day 1, 2 and 5-7 with neurological examination including National Institute of Health Stroke Scale (NIHSS) scoring and stroke MRI including T2*, DWI, TOF-MRA, FLAIR and PI. PI is conducted as dynamic susceptibility-enhanced contrast imaging with a fixed dosage of 5 ml 1 M Gadobutrol. For post-processing of PI, mean transit time (MTT) parametric images are determined by deconvolution of the arterial input function (AIF) which is automatically identified. Lesion volumes and mismatch are measured and calculated by using the perfusion mismatch analyzer (PMA) software from ASIST-Japan. Primary endpoint is the change of infarct size between baseline examination and day 5-7 follow up.

Discussions

The aim of this study is to describe the incidence of mismatch and the predictive value of PI for final lesion size and functional outcome depending on delay of imaging and vascular recanalization. It is crucial to standardize PI for future randomized clinical trials as for individual therapeutic decisions and we expect to contribute to this challenging task.

Trial Registration

clinicaltrials.gov NCT00715533
Expression of HIWI in human esophageal squamous cell carcinoma is significantly associated with poorer prognosis
Authors: He Wei , Wang Zhihui , Wang Qi , Fan Qingxia , Shou Chengcao , Wang Junsheng , Giercksky Karl-Erik , Nesland Jahn M , Suo Zhenhe
Published: December 2009

Background

HIWI, the human homologue of Piwi family, is present in CD34+ hematopoietic stem cells and germ cells, but not in well-differentiated cell populations, indicating that HIWI may play an impotent role in determining or maintaining stemness of these cells. That HIWI expression has been detected in several type tumours may suggest its association with clinical outcome in cancer patients.

Methods

With the methods of real-time PCR, western blot, immunocytochemistry and immunohistochemistry, the expression of HIWI in three esophageal squamous cancer cell lines KYSE70, KYSE140 and KYSE450 has been characterized. Then, we investigated HIWI expression in a series of 153 esophageal squamous cell carcinomas using immunohistochemistry and explored its association with clinicopathological features.

Results

The expression of HIWI was observed in tumour cell nuclei or/and cytoplasm in 137 (89.5%) cases, 16 (10.5%) cases were negative in both nuclei and cytoplasm. 86 (56.2%) were strongly positive in cytoplasm, while 49 (32.0%) were strongly positive in nuclei. The expression level of HIWI in cytoplasm of esophageal cancer cells was significantly associated with histological grade (P = 0.011), T stage (P = 0.035), and clinic outcome (P < 0.001), while there was no correlation between the nuclear HIWI expression and clinicopathological features.

Conclusion

The expression of HIWI in the cytoplasm of esophageal cancer cells is significantly associated with higher histological grade, clinical stage and poorer clinical outcome, indicating its possible involvement in cancer development.
Capnometry in suspected pulmonary embolism with positive D-dimer in the field
Authors: Rumpf Tadeja Hernja , Križmarić Miljenko , Grmec Štefek
Published: December 2009

Introduction

Pulmonary embolism (PE) is one of the greatest diagnostic challenges in prehospital emergency setting. Most patients with suspected PE have a positive D-dimer and undergo diagnostic testing. Excluding PE with additional non-invasive tests would reduce the need for further imaging tests. We aimed to determine the effectiveness of combination of clinical probability and end-tidal carbon dioxide (PetCO2) for evaluation of suspected PE with abnormal concentrations of D-dimer in prehospital emergency setting.

Methods

We assessed clinical probability of PE and PetCO2 measurement in 100 consecutive patients with suspected PE and positive D-dimer in the field. PetCO2 > 28 mmHg was considered as the best cut-off point. PE was excluded or confirmed by hospital physicians in the University Clinical Center Maribor by computer tomography (CT), ventilation/perfusion scan echocardiography and pulmonary angiography.

Results

PE was confirmed in 41 patients. PetCO2 had a sensitivity of 92.6% (95% CI, 79 to 98%), a negative predictive value of 94.2% (95% CI, 83 to 99%), a specificity of 83% (95% CI, 71 to 91%) and a positive predictive value of 79.2% (95% CI, 65 to 89%). Thirty-five patients (35%) had both a low (PE unlikely) clinical probability and a normal PetCO2 (sensitivity: 100%, 95% CI: 89 to 100%) and twenty-eight patients (28%) had both a high clinical probability (PE likely) and abnormal PetCO2 (specificity: 93.2%, 95% CI: 83 to 98%).

Conclusions

The combination of clinical probability and PetCO2 may safely rule out PE in patients with suspected PE and positive D-dimer in the prehospital setting.
Epithelial Cell Transforming Protein 2 (ECT2) Depletion Blocks Polar Body Extrusion and Generates Mouse Oocytes Containing Two Metaphase II Spindles
Authors: Elbaz Judith , Reizel Yitzhak , Nevo Nava , Galiani Dalia , Dekel Nava
Published: December 2009

Completion of the first meiosis in oocytes is achieved by the extrusion of the first polar body (PBI), a particular example of cell division. In mitosis, the small GTPase RhoA, which is activated by epithelial cell transforming protein 2 (ECT2), orchestrates contractile ring constriction, thus enabling cytokinesis. However, the involvement of this pathway in mammalian oocytes has not been established. To characterize the role of ECT2 in PBI emission in mouse oocytes, the small interfering RNA approach was employed. We found that ECT2 depletion significantly reduces PBI emission, induces first metaphase arrest, and generates oocytes containing two properly formed spindles of the second metaphase. Moreover, we describe, for the first time, that before PBI emission, RhoA forms a ring that is preceded by a dome-like accumulation at the oocyte cortex, next to the spindle. This unique mode of RhoA translocation failed to occur in the absence of ECT2. We further found that the Rho-dependent kinase, a main RhoA effector, is essential for PBI emission. In addition, we demonstrate herein that ECT2 is subjected to phosphorylation/dephosphorylation throughout meiosis in oocytes and further reveal that PBI emission is temporally associated with ECT2 dephosphorylation. Our data provide the first demonstration that an active cyclin-dependent kinase 1, the catalytic subunit of the maturation-promoting factor, phosphorylates ECT2 during the first meiotic metaphase and that cyclin-dependent kinase 1 inactivation at anaphase allows ECT2 dephosphorylation. In conclusion, our study demonstrates the indispensable role of the maturation-promoting factor/ECT2/RhoA pathway in PBI extrusion in mouse oocytes.
Hypothalamic Actions of Tumor Necrosis Factor α Provide the Thermogenic Core for the Wastage Syndrome in Cachexia
Authors: Arruda Ana Paula , Milanski Marciane , Romanatto Talita , Solon Carina , Coope Andressa , Alberici Luciane C. , Festuccia William T. , Hirabara Sandro M. , Ropelle Eduardo , Curi Rui , Carvalheira José B. , Vercesi Aníbal E. , Velloso Licio A.
Published: December 2009

TNFα is an important mediator of catabolism in cachexia. Most of its effects have been characterized in peripheral tissues, such as skeletal muscle and fat. However, by acting directly in the hypothalamus, TNFα can activate thermogenesis and modulate food intake. Here we show that high concentration TNFα in the hypothalamus leads to increased O2 consumption/CO2 production, increased body temperature, and reduced caloric intake, resulting in loss of body mass. Most of the thermogenic response is produced by β3-adrenergic signaling to the brown adipose tissue (BAT), leading to increased BAT relative mass, reduction in BAT lipid quantity, and increased BAT mitochondria density. The expression of proteins involved in BAT thermogenesis, such as β3-adrenergic receptor, peroxisomal proliferator-activated receptor-γ coactivator-1α, and uncoupling protein-1, are increased. In the hypothalamus, TNFα produces reductions in neuropeptide Y, agouti gene-related peptide, proopiomelanocortin, and melanin-concentrating hormone, and increases CRH and TRH. The activity of the AMP-activated protein kinase signaling pathway is also decreased in the hypothalamus of TNFα-treated rats. Upon intracerebroventricular infliximab treatment, tumor-bearing and septic rats present a significantly increased survival. In addition, the systemic inhibition of β3-adrenergic signaling results in a reduced body mass loss and increased survival in septic rats. These data suggest hypothalamic TNFα action to be important mediator of the wastage syndrome in cachexia.
Consequences of Monocarboxylate Transporter 8 Deficiency for Renal Transport and Metabolism of Thyroid Hormones in Mice
Authors: Trajkovic-Arsic Marija , Visser Theo J. , Darras Veerle M. , Friesema Edith C. H. , Schlott Bernhard , Mittag Jens , Bauer Karl , Heuer Heike
Published: December 2009

Patients carrying inactivating mutations in the gene encoding the thyroid hormone transporting monocarboxylate transporter (MCT)-8 suffer from a severe form of psychomotor retardation and exhibit abnormal serum thyroid hormone levels. The thyroidal phenotype characterized by high-serum T3 and low-serum T4 levels is also found in mice mutants deficient in MCT8 although the cause of these abnormalities is still unknown. Here we describe the consequences of MCT8 deficiency for renal thyroid hormone transport, metabolism, and function by studying MCT8 null mice and wild-type littermates. Whereas serum and urinary parameters do not indicate a strongly altered renal function, a pronounced induction of iodothyronine deiodinase type 1 expression together with increased renal T3 and T4 content point to a general hyperthyroid state of the kidneys in the absence of MCT8. Surprisingly, accumulation of peripherally injected T4 and T3 into the kidneys was found to be enhanced in the absence of MCT8, indicating that MCT8 deficiency either directly interferes with the renal efflux of thyroid hormones or activates indirectly other renal thyroid hormone transporters that preferentially mediate the renal uptake of thyroid hormones. Our findings indicate that the enhanced uptake and accumulation of T4 in the kidneys of MCT8 null mice together with the increased renal conversion of T4 into T3 by increased renal deiodinase type 1 activities contributes to the generation of the low-serum T4 and the increase in circulating T3 levels, a hallmark of MCT8 deficiency.
Diet-Induced Weight Loss and Exercise Alone and in Combination Enhance the Expression of Adiponectin Receptors in Adipose Tissue and Skeletal Muscle, but Only Diet-Induced Weight Loss Enhanced Circulating Adiponectin
Authors: Christiansen Tore , Paulsen Søren K. , Bruun Jens M. , Ploug Thorkil , Pedersen Steen B. , Richelsen Bjørn
Published: December 2009

Objective: The aim of the study was to investigate the effect of weight loss and exercise independently and in combination on circulating levels of adiponectin including low molecular weight, medium molecular weight, and high molecular weight adiponectin and expression of adiponectin and adiponectin receptors (AdipoR) in adipose tissue (AT) and skeletal muscle (SM).

Design and Methods: Seventy-nine obese males and females were randomized into the following: 1) exercise only (12 wk of exercise without diet restriction); 2) hypocaloric diet [8 wk of very low energy diet (600 kcal/d) followed by 4 wk with a weight maintenance diet]; and 3) hypocaloric diet and exercise (DEX; 8 wk very low energy diet 800 kcal/d followed by 4 wk weight maintenance diet combined with exercise throughout the 12 wk). Blood samples and biopsies from sc abdominal AT and SM were collected at baseline and after 12 wk. The molecular subforms of adiponectin in serum were determined by Western blot.

Results: The mRNA expression of AdipoR1 and -2 in SM was increased significantly in the exercise-only and DEX groups (both P < 0.05). The mRNA expression of adiponectin and AdipoRs in AT was increased significantly in all three groups (all P < 0.01), whereas serum total circulating adiponectin was significantly increased only in the DEX and hypocaloric diet groups (both P < 0.01). All the adiponectin subforms changed in a similar manner as total adiponectin, indicating no specific regulation of any of the subforms by the intervention.

Conclusion: Exercise alone and in combination with a diet-induced weight loss enhance the mRNA expression of adiponectin receptors in AT and in SM but only a pronounced hypocaloric-induced weight-loss increases circulating adiponectin in obese subjects.
Metformin Reduces Arterial Stiffness and Improves Endothelial Function in Young Women with Polycystic Ovary Syndrome: A Randomized, Placebo-Controlled, Crossover Trial
Authors: Agarwal Neera , Rice Sam P. L. , Bolusani Hemanth , Luzio Stephen D. , Dunseath Gareth , Ludgate Marian , Rees D. Aled
Published: December 2009

Context: Patients with polycystic ovary syndrome (PCOS) have an increased prevalence of insulin resistance and display subclinical evidence of early cardiovascular disease. Metformin improves insulin sensitivity and circulating markers of cardiovascular risk in patients with PCOS, but it is unclear whether this translates into improvements in vascular function.

Objective: Our objective was to evaluate the effects of metformin on arterial stiffness and endothelial function in women with PCOS.

Design and Intervention: Thirty women with PCOS were assigned to consecutive 12-wk treatment periods of metformin or placebo in a randomized, double-blind, crossover design separated by an 8-wk washout.

Main Outcome Measures: The primary outcome measures were assessments of arterial stiffness [augmentation index (AIx), central blood pressure, and brachial and aortic pulse wave velocity (PWV)] and endothelial function. Anthropometry, testosterone, and metabolic biochemistry (lipids, homeostasis model of assessment for insulin resistance, high-sensitivity C-reactive protein, adiponectin, and plasminogen activator inhibitor-1) were also assessed.

Results: Metformin improved AIx [−6.1%; 95% confidence interval (CI) for the difference −8.5 to −3.5%; P < 0.001], aortic PWV (−0.76 m/sec; 95% CI for the difference −1.12 to −0.4 m/sec; P < 0.001), brachial PWV (−0.73 m/sec; 95% CI for the difference −1.09 to −0.38; P < 0.001), central blood pressure (P < 0.001), and endothelium-dependent (AIx after albuterol; P = 0.003) and endothelium-independent (AIx after nitroglycerin; P < 0.001) vascular responses. Metformin also reduced weight (P < 0.001), waist circumference (P < 0.001), and triglycerides (P = 0.004) and increased adiponectin (P = 0.001) but did not affect testosterone or other metabolic measures.

Conclusions: Short-term metformin therapy improves arterial stiffness and endothelial function in young women with PCOS.
Piston rod load analysis of process reciprocating machines
Authors: Almasi A
Published: December 2009

A new analytical method is presented to evaluate the dynamic deformation and elastic—plastic stress and strain in a reciprocating machine piston rod. This new method has the ability to account for geometric non-linearity, initial rod imperfection, elastic—plastic deformation, and dynamic effects. The proposed method can be used for the evaluation of piston rod performance for various reciprocating machines under different operation situations. Rod load curves and the maximum allowable rod load are calculated with the proposed method for a special purpose reciprocating compressor in a refinery critical service.
Robust variable structure attitude control with L2-gain performance for a flexible spacecraft including input saturation
Authors: Hu Q , Friswell M I
Published: December 2009

This paper presents the design of a robust controller, based on variable structure control, for the rotational manoeuvring and vibration reduction of a flexible spacecraft with input saturation. The dynamic equations of motion are formulated as a finite dimensional mathematical model, but accounting for the infinite number of natural vibration modes of the flexible appendages. Based on this model, a variable structure controller is designed for rotational manoeuvres and vibration suppression, and its exponential stability is demonstrated. The synthesis of the control system assumes that only the pitch angle and its derivative are accessible for feedback, and that the flexible modes are not measured. Saturation limits are introduced into the controller design to cope with the actuation limitations, and the stability of the modified control solution is verified. The prescribed robust performance is obtained by ensuring that the L2-gain synthesis, from a torque disturbance to the penalty output, is less than a specified level. Simulation results are presented for the attitude manoeuvring and elastic mode stabilization of an orbiting flexible spacecraft; these results demonstrate the excellent performance of the proposed controller and illustrate its robustness to external disturbances.
Risk Taking by Entrepreneurs
Authors: Vereshchagina Galina , Hopenhayn Hugo A.
Published: December 2009

Entrepreneurs bear substantial risk, but empirical evidence shows no sign of a positive premium. This paper develops a theory of endogenous entrepreneurial risk taking that explains why self-financed entrepreneurs may find it optimal to invest in risky projects offering no risk premium. Consistently with empirical evidence, the model predicts that poorer entrepreneurs are more likely to undertake risky projects. It also finds that incentives for risk taking are stronger when agents are impatient. (JEL G31, G32, L25, L26)
Strategy-proofness versus Efficiency in Matching with Indifferences: Redesigning the NYC High School Match
Authors: Abdulkadiroğlu Atila , Pathak Parag A. , Roth Alvin E.
Published: December 2009

The design of the New York City (NYC) high school match involved trade-offs among efficiency, stability, and strategy-proofness that raise new theoretical questions. We analyze a model with indifferences—ties—in school preferences. Simulations with field data and the theory favor breaking indifferences the same way at every school—single tiebreaking—in a student-proposing deferred acceptance mechanism. Any inefficiency associated with a realized tiebreaking cannot be removed without harming student incentives. Finally, we empirically document the extent of potential efficiency loss associated with strategy-proofness and stability, and direct attention to some open questions. (JEL C78, D82, I21)
Performance Pay and Teachers' Effort, Productivity, and Grading Ethics
Authors: Lavy Victor
Published: December 2009

This paper presents evidence about the effect of individual monetary incentives on English and math teachers in Israel. Teachers were rewarded with cash bonuses for improving their students' performance in high-school matriculation exams. The main identification strategy is based on measurement error in the assignment to treatment variable that produced a randomized treatment sample. The incentives led to significant improvements in test taking rates, conditional pass rates, and mean test scores. Improvements were mediated through changes in teaching methods, enhanced after-school teaching, and increased responsiveness to students' needs. No evidence was found of manipulation of test scores by teachers. (JEL I21, J31, J45)
Surprised by the Parimutuel Odds?
Authors: Ottaviani Marco , Sørensen Peter Norman
Published: December 2009

Empirical analyses of parimutuel betting markets have documented that market probabilities of favorites (longshots) tend to underestimate (overestimate) the corresponding empirical probabilities. We argue that this favorite-longshot bias is consistent with bettors taking simultaneous positions on the basis of private information about the likelihood of different outcomes. The ex post realization of a high market probability indicates favorable information about the occurrence of an outcome—and the opposite is true for longshots. This explanation for the bias relies on the bettors' inability to incorporate the surprise revealed by the final odds. (JEL D81, D82, L83)
Individual Behavior and Group Membership: Comment
Authors: Sutter Matthias
Published: December 2009

Charness et al. (2007b) have shown that group membership has a strong effect on individual decisions in strategic games when group membership is salient through payoff commonality. In this comment, I show that their findings also apply to nonstrategic decisions, even when no outgroup exists, and I relate the effects of group membership on individual decisions to joint decision making in teams. I find in an investment experiment that individual decisions with salient group membership are largely the same as team decisions. This finding bridges the literature on team decision making and on group membership effects. (JEL D71, D82, Z13)