bluuebunny/crossref_metadata_2025 huggingface dataset:
Positive autoregulation of the transcription factor Pax6 in response to increased levels of either of its major isoforms, Pax6 or Pax6(5a), in cultured cells
Authors: Pinson Jeni , Simpson T Ian , Mason John O , Price David J
Published: May 2006

Background

Pax6 is a transcription factor essential for normal development of the eyes and nervous system. It has two major isoforms, Pax6 and Pax6(5a), and the ratios between their expression levels vary within narrow limits. We tested the effects of overexpressing either one or other isoform on endogenous Pax6 expression levels in Neuro2A and NIH3T3 cells.

Results

We found that both isoforms caused an up-regulation of endogenous Pax6 expression in cells with (Neuro2A) or without (NIH3T3) constitutive Pax6 expression. Western blots showed that cells stably transfected with constructs expressing either Pax6 or Pax6(5a) contained raised levels of both Pax6 and Pax6(5a). Quantitative RT-PCR confirmed an increase in levels of Pax6(5a) mRNA in cells containing Pax6-expressing constructs and an increase in levels of Pax6 mRNA in cells containing Pax6(5a)-expressing constructs. The fact that the introduction of constructs expressing only one isoform increased the cellular levels of not only that isoform but also the other indicates that activation of the endogenous Pax6 locus occurred. The ratio between the levels of the two isoforms was maintained close to physiological values. The overexpression of either isoform in neuroblastoma (Neuro2A) cell lines also promoted morphological change and an increase in β-III-tubulin expression, indicating an increase in neurogenesis.

Conclusion

Our results demonstrate that Pax6 can up-regulate production of Pax6 protein from an entire intact endogenous Pax6 locus in its genomic environment. This adds to previous studies showing that Pax6 can up-regulate reporter expression driven by isolated Pax6 regulatory elements. Furthermore, our results suggest that an important function of positive feedback might be to stabilise the relative levels of Pax6 and Pax6(5a).
Genotyping of β-Lactoglobulin gene by PCR-RFLP in Sahiwal and Tharparkar cattle breeds
Authors: Rachagani Satyanarayana , Gupta Ishwar Dayal , Gupta Neelam , Gupta SC
Published: May 2006

Background

Improvement of efficiency and economic returns is an important goal in dairy farming, as in any agricultural enterprise. The primary goal of dairy industry has been to identify an efficient and economical way of increasing milk production and its constituents without increasing the size of the dairy herd. Selection of animals with desirable genotypes and mating them to produce the next generation has been the basis of livestock improvement and this would continue to remain the same in the coming years. The use of polymorphic genes as detectable molecular markers is a promising alternative to the current methods of trait selection once these genes are proven to be associated with traits of interest in animals. The point mutations in exon IV of bovine β-Lactoglobulin gene determine two allelic variants A and B. These variants were distinguished by Polymerase Chain Reaction and Restriction Fragment Length Polymorphism (PCR-RFLP) analysis in two indigenous Bos indicus breeds viz. Sahiwal and Tharparkar cattle. DNA samples (228 in Sahiwal and 86 in Tharparkar) were analyzed for allelic variants of β-Lactoglobulin gene. Polymorphism was detected by digestion of PCR amplified products with Hae III enzyme, and separation on 12% non-denaturing gels and resolved by silver staining.

Results

The allele B of β-Lactoglobulin occurred at a higher frequency than the allele A in both Sahiwal and Tharparkar breeds. The genotypic frequencies of AA, AB, and BB in Sahiwal and Tharparkar breeds were 0.031, 0.276, 0.693 and 0.023, 0.733, 0.244 respectively. Frequencies of A and B alleles were 0.17 and 0.83, and 0.39 and 0.61 in Sahiwal and Tharparkar breeds respectively. The Chi-square test results (at one degree of freedom at one per cent level) revealed that the Tharparkar population was not in Hardy-Weinberg equilibrium as there was a continuous migration of animals in the herd studied, where as, the results are not significant for the Sahiwal population.

Conclusion

Genotype frequencies of AA were the lowest compared to that of BB genotype in Sahiwal cattle while AB genotypes were more frequent in Tharparkar cattle. The frequency of A allele was found to be lower than that of B allele in both the breeds studied. These results further confirm that Bos indicus cattle are predominantly of β-Lactoglobulin B type than Bos taurus breeds.
Meta-analysis on the effect of the N363S polymorphism of the glucocorticoid receptor gene (GRL) on human obesity
Authors: Marti Amelia , Ochoa M Carmen , Sánchez-Villegas Almudena , Martínez J Alfredo , Martínez-González Miguel Angel , Hebebrand Johannes , Hinney Anke , Vedder Helmut
Published: May 2006

Background

Since both excess glucocorticoid secretion and central obesity are clinical features of some obese patients, it is worthwhile to study a possible association of glucocorticoid receptor gene (GRL) variants with obesity. Previous studies have linked the N363S variant of the GRL gene to increased glucocorticoid effects such as higher body fat, a lower lean-body mass and a larger insulin response to dexamethasone. However, contradictory findings have been also reported about the association between this variant and obesity phenotypes. Individual studies may lack statistical power which may result in disparate results. This limitation can be overcome using meta-analytic techniques.

Methods

We conducted a meta-analysis to assess the association between the N363S polymorphism of the GRL gene and obesity risk. In addition to published research, we included also our own unpublished data -three novel case-control studies- in the meta-analysis The new case-control studies were conducted in German and Spanish children, adolescents and adults (total number of subjects: 1,117). Genotype was assessed by PCR-RFLP (Tsp509I). The final formal meta-analysis included a total number of 5,909 individuals.

Results

The meta-analysis revealed a higher body mass index (BMI) with an overall estimation of +0.18 kg/m2 (95% CI: +0.004 to +0.35) for homo-/heterozygous carriers of the 363S allele of the GRL gene in comparison to non-carriers. Moreover, differences in pooled BMI were statistically significant and positive when considering one-group studies from the literature in which participants had a BMI below 27 kg/m2 (+ 0.41 kg/m2 [95% CI +0.17 to +0.66]), but the differences in BMI were negative when only our novel data from younger (aged under 45) and normal weight subjects were pooled together (-0.50 kg/m2 [95% CI -0.84 to -0.17]). The overall risk for obesity for homo-/heterozygous carriers of the 363S allele was not statistically significant in the meta-analysis (pooled OR = 1.02; 95% CI: 0.56–1.87).

Conclusion

Although certain genotypic effects could be population-specific, we conclude that there is no compelling evidence that the N363S polymorphism of the GRL gene is associated with either average BMI or obesity risk.
Polymorphisms in thymidylate synthase gene and susceptibility to breast cancer in a Chinese population: a case-control analysis
Authors: Zhai Xiangjun , Gao Jun , Hu Zhibin , Tang Jinhai , Qin Jianwei , Wang Shui , Wang Xuechen , Jin Guangfu , Liu Jiyong , Chen Wenshen , Chen Feng , Wang Xinru , Wei Qingyi , Shen Hongbing
Published: May 2006

Background

Accumulative evidence suggests that low folate intake is associated with increased risk of breast cancer. Polymorphisms in genes involved in folate metabolism may influence DNA methylation, nucleotide synthesis, and thus individual susceptibility to cancer. Thymidylate synthase (TYMS) is a key enzyme that participates in folate metabolism and catalyzes the conversion of dUMP to dTMP in the process of DNA synthesis. Two potentially functional polymorphisms [a 28-bp tandem repeat in the TYMS 5'-untranslated enhanced region (TSER) and a 6-bp deletion/insertion in the TYMS 3'-untranslated region (TS 3'-UTR)] were suggested to be correlated with alteration of thymidylate synthase expression and associated with cancer risk.

Methods

To test the hypothesis that polymorphisms of the TYMS gene are associated with risk of breast cancer, we genotyped these two polymorphisms in a case-control study of 432 incident cases with invasive breast cancer and 473 cancer-free controls in a Chinese population.

Results

We found that the distribution of TS3'-UTR (1494del6) genotype frequencies were significantly different between the cases and controls (P = 0.026). Compared with the TS3'-UTR del6/del6 wild-type genotype, a significantly reduced risk was associated with the ins6/ins6 homozygous variant genotype (adjusted OR = 0.58, 95% CI = 0.35–0.97) but not the del6/ins6 genotype (OR = 1.09, 95% CI = 0.82–1.46). Furthermore, breast cancer risks associated with the TS3'-UTR del6/del6 genotype were more evident in older women, postmenopausal subjects, individuals with a younger age at first-live birth and individuals with an older age at menarche. However, there was no evidence for an association between the TSER polymorphism and breast cancer risks.

Conclusion

These findings suggest that the TS3'-UTR del6 polymorphism may play a role in the etiology of breast cancer. Further larger population-based studies as well as functional evaluation of the variants are warranted to confirm our findings.
Views of new internal medicine faculty of their preparedness and competence in physician-patient communication
Authors: Mueller Paul S , Barrier Patricia A , Call Timothy G , Duncan Alan K , Hurley Daniel L , Multari Adamarie , Rabatin Jeffrey T , Li James TC
Published: May 2006

Background

We sought to assess self-rated importance of the medical interview to clinical practice and competence in physician-patient communication among new internal medicine faculty at an academic medical center.

Methods

Since 2001, new internal medicine faculty at the Mayo Clinic College of Medicine (Rochester, Minnesota) have completed a survey on physician-patient communication. The survey asks the new faculty to rate their overall competence in medical interviewing, the importance of the medical interview to their practice, their confidence and adequacy of previous training in handling eight frequently encountered challenging communication scenarios, and whether they would benefit from additional communication training.

Results

Between 2001 and 2004, 75 general internists and internal medicine subspecialists were appointed to the faculty, and of these, 58 (77%) completed the survey. The faculty rated (on a 10-point scale) the importance of the medical interview higher than their competence in interviewing; this difference was significant (average ± SD, 9.4 ± 1.0 vs 7.7 ± 1.2, P < .001). Similar results were obtained by sex, age, specialty, years since residency or fellowship training, and perceived benefit of training. Experienced faculty rated their competence in medical interviewing and the importance of the medical interview higher than recent graduates (ie, less than one year since training). For each challenging communication scenario, the new faculty rated the adequacy of their previous training in handling the scenario relatively low. A majority (57%) said they would benefit from additional communication training.

Conclusion

Although new internal medicine faculty rate high the importance of the medical interview, they rate their competence and adequacy of previous training in medical interviewing relatively low, and many indicate that they would benefit from additional communication training. These results should encourage academic medical centers to make curricula in physician-patient communication available to their faculty members because many of them not only care for patients, but also teach clinical skills, including communication skills, to trainees.
Lessons and implications from a mass immunization campaign in squatter settlements of Karachi, Pakistan: an experience from a cluster-randomized double-blinded vaccine trial [NCT00125047]
Authors: Khan Mohammad Imran , Ochiai Rion Leon , Hamza Hasan Bin , Sahito Shah Muhammad , Habib Muhammad Atif , Soofi Sajid Bashir , Bhutto Naveed Sarwar , Rasool Shahid , Puri Mahesh K , Ali Mohammad , Wasan Shafi Mohammad , Khan Mohammad Jawed , Abu-Elyazeed Remon , Ivanoff Bernard , Galindo Claudia M , Pang Tikki , Donner Allan , von Seidlein Lorenz , Acosta Camilo J , Clemens John D , Nizami Shaikh Qamaruddin , Bhutta Zulfiqar A
Published: May 2006

Objective

To determine the safety and logistic feasibility of a mass immunization strategy outside the local immunization program in the pediatric population of urban squatter settlements in Karachi, Pakistan.

Methods

A cluster-randomized double blind preventive trial was launched in August 2003 in 60 geographic clusters covering 21,059 children ages 2 to 16 years. After consent was obtained from parents or guardians, eligible children were immunized parenterally at vaccination posts in each cluster with Vi polysaccharide or hepatitis A vaccine. Safety, logistics, and standards were monitored and documented.

Results

The vaccine coverage of the population was 74% and was higher in those under age 10 years. No life-threatening serious adverse events were reported. Adverse events occurred in less than 1% of all vaccine recipients and the main reactions reported were fever and local pain. The proportion of adverse events in Vi polysaccharide and hepatitis A recipients will not be known until the end of the trial when the code is broken. Throughout the vaccination campaign safe injection practices were maintained and the cold chain was not interrupted. Mass vaccination in slums had good acceptance. Because populations in such areas are highly mobile, settlement conditions could affect coverage. Systemic reactions were uncommon and local reactions were mild and transient. Close community involvement was pivotal for information dissemination and immunization coverage.

Conclusion

This vaccine strategy described together with other information that will soon be available in the area (cost/effectiveness, vaccine delivery costs, etc) will make typhoid fever control become a reality in the near future.
Measuring Moral Distress in Pharmacy and Clinical Practice
Authors: Sporrong Sofia Kälvemark , Höglund Anna T , Arnetz Bengt
Published: May 2006

This article presents the development, validation and application of an instrument to measure everyday moral distress in different health care settings. The concept of moral distress has been discussed and developed over 20 years. A few instruments have been developed to measure it, predominantly in nursing. The instrument presented here consists of two factors: level of moral distress, and tolerance/openness towards moral dilemmas. It was tested in four medical departments and three pharmacies, where 259 staff members completed a questionnaire. The two factors were found to be reliable. Differences in levels of moral distress were found between pharmacies and clinical departments, and between the youngest and oldest age groups; departmental staff and the youngest group experienced higher levels of moral distress. Departments reported less tolerance/openness towards moral dilemmas than pharmacies. The instrument needs to be tested further, but its strengths are the focus on everyday ethical dilemmas and its usefulness in different health care settings.
Everyday Ethical Problems in Dementia Care: A teleological Model
Authors: Bolmsjö Ingrid Ågren , Edberg Anna-Karin , Sandman Lars
Published: May 2006

In this article, a teleological model for analysis of everyday ethical situations in dementia care is used to analyse and clarify perennial ethical problems in nursing home care for persons with dementia. This is done with the aim of describing how such a model could be useful in a concrete care context. The model was developed by Sandman and is based on four aspects: the goal; ethical side-constraints to what can be done to realize such a goal; structural constraints; and nurses’ ethical competency. The model contains the following main steps: identifying and describing the normative situation; identifying and describing the different possible alternatives; assessing and evaluating the different alternatives; and deciding on, implementing and evaluating the chosen alternative. Three ethically difficult situations from dementia care were used for the application of the model. The model proved useful for the analysis of nurses’ everyday ethical dilemmas and will be further explored to evaluate how well it can serve as a tool to identify and handle problems that arise in nursing care.
An Automated Electronic Case Log: Using Electronic Information Systems to Assess Training in Emergency Medicine
Authors: Nagler Joshua , Harper Marvin B. , Bachur Richard G.
Published: May 2006

As part of the Outcome Project of the Accreditation Council for Graduate Medical Education, training programs are required to evaluate trainees across six general competencies. Assessment of the patient‐care competency by direct observation can be supplemented with a quantification of overall experience through the use of case logs. However, manual entry of information into such registries frequently is incomplete. The authors report on the development of an automated electronic case log as a novel tool for evaluating the experience of individual trainees or an entire training program. Specific examples of use of the case log are provided. The authors use a pediatric emergency medicine fellowship as a paradigm to demonstrate the potential utility across all emergency medicine training programs. In addition, the authors discuss how additional information technologies might be incorporated to further these evaluative efforts in the future.
Multimarker Panel to Rule Out Acute Coronary Syndromes in Low‐risk Patients
Authors: Mitchell Alice M. , Garvey Joseph Lee , Kline Jeffrey A.
Published: May 2006

Objectives:
To test novel markers of acute coronary syndrome (ACS), monocyte chemoattractant protein‐1 (MCP), myeloperoxidase (MPO), C‐reactive protein (CRP), and brain natriuretic peptide (BNP) in low‐risk emergency department (ED) patients who were evaluated for ACS in a chest pain unit (CPU).

Methods:
A convenience sample of 414 patients underwent CPU evaluation, including provocative testing, and were followed prospectively for 45 days for ACS, which was defined as death, myocardial infarction (MI), revascularization, or >60% coronary artery stenosis prompting new medical treatment, adjudicated by three blinded reviewers. Published diagnostic thresholds were used to calculate diagnostic indices for each marker and for the multimarker panel.

Results:
The prevalence of ACS was 7 in 414 (1.7%; 95% CI = 0.7% to 3.5%). Only MCP demonstrated a negative likelihood ratio [LR(–)] of less than 0.5, with a sensitivity of 85% (95% CI = 42% to 99%), specificity of 72% (95% CI = 67% to 76%), and LR(–) of 0.20 (95% CI = 0.04 to 0.71). For MPO, CRP, and BNP, LR(–) was 0.89 (95% CI = 0.26 to 2.05), 0.79 (95% CI = 0.40 to 1.01), and 0.90 (95% CI = 0.51 to 1.03), respectively. The sensitivity, specificity, and LR(–) of an abnormal multimarker panel were 86% (95% CI = 42% to 100%), 17% (95% CI = 13% to 21%), and 0.84 (95% CI = 0.15 to 3.12), respectively.

Conclusions:
The prevalence of ACS was very low but was similar to reports from other CPUs. BNP and CRP had high specificities, but had limited sensitivities, whereas MPO had a low specificity. Only MCP had a low LR(–) and should be studied further. The combined multimarker panel had an unexpectedly low sensitivity and specificity, yielding an LR(–) of 0.84, suggesting that the panel would not be an efficient screening test to decrease unnecessary CPU testing.
Origin and Ontogeny of Mammalian Ovarian Neurons
Authors: Dees W. Les , Hiney J. K. , McArthur N. H. , Johnson G. A. , Dissen G. A. , Ojeda S. R.
Published: May 2006

Mammalian ovaries contain sympathetic neurons expressing the low affinity neurotropin receptor (p75NTR). To date neither the role these neurons might play in ovarian physiology nor their embryological origin is known. Immunohistochemistry was used to detect postnatal changes in distribution and number of both p75NTR-positive and tyrosine hydroxylase-positive neurons in rhesus monkey ovaries. Pig fetuses were used to map the pathway of ovarian neuronal migration during embryonic development. Antiserum to p75NTR revealed the presence of isolated neurons and neurons clustered into ganglia in 2-month-old monkey ovaries. After 8 months, the neurons exhibited well-developed processes, and other than being more extensively interlaced, the localization and morphology did not change after 2 yr of age. Total number of p75NTR-positive neurons present decreased gradually between 2 months and 12 yr of age and declined markedly with reproductive aging. Conversely, the subpopulation of neurons immunoreactive to anti-tyrosine hydroxylase increased significantly at puberty and then declined with the loss of reproductive capacity. By d 21 of fetal life in the pig, p75NTR neurons had migrated medially from the neural crest to form the paraaortic autonomic ganglia. Some neurons migrated ventrally from the ganglia and then continued ventrolaterally to enter the genital ridge. By d 27, neurons had entered the developing ovary, and by d 35, the migration was complete with neurons demonstrating immunoreactivity to NeuN, a neuron-specific marker. Results demonstrate that p75NTR-expressing ovarian neurons originate from the neural crest and that a catecholaminergic subset is associated with pubertal maturation of the ovary and subsequent reproductive function.
Non-cell-autonomous action of STAT3 in maintenance of neural precursor cells in the mouse neocortex
Authors: Yoshimatsu Takeshi , Kawaguchi Daichi , Oishi Koji , Takeda Kiyoshi , Akira Shizuo , Masuyama Norihisa , Gotoh Yukiko
Published: May 2006

The transcription factor STAT3 promotes astrocytic differentiation of neural precursor cells (NPCs) during postnatal development of the mouse neocortex, but little has been known of the possible role of STAT3 in the embryonic neocortex. We now show that STAT3 is expressed in NPCs of the mouse embryonic neocortex and that the JAK-STAT3 signaling pathway plays an essential role in the maintenance of NPCs by fibroblast growth factor 2. Conditional deletion of the STAT3 gene in NPCs reduced their capacity to form neurospheres in vitro, as well as promoted neuronal differentiation both in vitro and in vivo. Furthermore, STAT3 was found to maintain NPCs in the undifferentiated state in a non-cell-autonomous manner. STAT3-dependent expression of the Notch ligand Delta-like1 (DLL1) appears to account for the non-cell-autonomous effect of STAT3 on NPC maintenance, as knockdown of DLL1 by RNA interference or inhibition of Notch activation with a γ-secretase inhibitor abrogated the enhancement of neurosphere formation by STAT3. Our results reveal a previously unrecognized mechanism of interaction between the JAK-STAT3 and DLL1-Notch signaling pathways, as well as a pivotal role for this interaction in maintenance of NPCs during early neocortical development.
Identification, emergence and mobilization of circulating endothelial cells or progenitors in the embryo
Authors: Pardanaud Luc , Eichmann Anne
Published: May 2006

Using quail-chick parabiosis and QH1 monoclonal antibody analysis, we have identified circulating endothelial cells and/or progenitors in the embryo. These cells were already present early in ontogeny, before the third embryonic day. Under normal conditions, they integrated into most tissues but remained scarce. When experimental angiogenic responses were induced by wounding or grafts onto the chorioallantoic membrane, circulating endothelial cells were rapidly mobilized and selectively integrated sites of neoangiogenesis. Their mobilization was not dependent on the presence of the bone marrow as it was effective before its differentiation. Surprisingly, mobilization was not effective during sprouting angiogenesis following VEGF treatment of chorioallantoic membrane. Thus, embryonic circulating endothelial cells were efficiently mobilized during the establishment of an initial vascular supply to ischemic tissues following wounding or grafting, but were not involved during classical sprouting angiogenesis.
Inhibition of calpain stabilises podosomes and impairs dendritic cell motility
Authors: Calle Yolanda , Carragher Neil O. , Thrasher Adrian J. , Jones Gareth E.
Published: May 2006

Podosomes, highly dynamic adhesion structures implicated in cell motility and extracellular matrix degradation, are characteristic of certain cells of the myeloid lineage and a limited range of other cell types. The nature and the mechanisms that regulate their high turnover are unknown at present. The cysteine protease calpain is involved in the regulation of cell migration in part by promoting either formation or disassembly of adhesion sites. Despite the fact that many known substrates of calpain are also structural components of the podosome complex, no studies have yet demonstrated that calpain participates in the regulation of podosome dynamics. In the present work, we show that inhibition of calpain in primary mouse dendritic cells leads to enhanced accumulation of actin filaments, the Wiskott Aldrich Syndrome protein (WASP), β2 integrins, talin, paxillin and vinculin in podosomes. This accumulation of components is associated with stabilisation of podosome turnover, overall reduction in velocity of cell locomotion and impaired transmigration across an endothelial monolayer. We also demonstrate that calpain cleaves the podosome components talin, Pyk2 and WASP in dendritic cells. In summary, our results provide evidence that calpain regulates podosome composition and turnover and that this process is required for efficient migration of dendritic cells.
Ubiquitin-proteasome-dependent degradation of mammalian ER stearoyl-CoA desaturase
Authors: Kato Hiroki , Sakaki Kenjiro , Mihara Katsuyoshi
Published: May 2006

Mammalian Δ9 stearoyl-CoA desaturase 1 (SCD1) is a key enzyme in the biosynthesis of mono-unsaturated fatty acids in the endoplasmic reticulum (ER). It is a short-lived multispanning ER membrane protein, reported to be degraded by the ubiquitin-proteasome-independent pathway. We have examined SCD1 protein degradation using cultured mammalian cells. Exogenously expressed SCD1 in CHO-K1 cells was localized to the ER and turned over with a half-life of ∼3 hours. Unexpectedly, proteasome inhibitors increased the half-life of SCD1 to ∼6 hours. Endogenously expressed SCD1 in adipocyte-differentiated NIH 3T3-L1 cells was also rapidly degraded in a proteasome inhibitor-sensitive manner. In the presence of proteasome inhibitors, polyubiquitylated SCD1 accumulated in the ER and interacted with AAA-ATPase p97, which is involved in ER-associated degradation (ERAD). The 66-residue N-terminal segment carrying the PEST sequence is mainly responsible for SCD1 degradation and this segment induced instability in an otherwise stable ER membrane protein. Furthermore, SCD1 was degraded constitutively irrespective of the cellular levels of unsaturated fatty acids, which strictly regulate SCD1 gene expression. These findings indicate that the ubiquitin-proteasome-dependent ERAD system is also involved in constitutive SCD1 degradation.
N-terminal residues in Cx43 and Cx40 determine physiological properties of gap junction channels, but do not influence heteromeric assembly with each other or with Cx26
Authors: Gemel Joanna , Lin Xianming , Veenstra Richard D. , Beyer Eric C.
Published: May 2006

The cytoplasmic N-terminal domain in the connexins (Cx) has been implicated in determining several properties including connexin hetero-oligomerization, channel gating and regulation by polyamines. To elucidate the roles of potentially crucial amino acids, we produced site-directed mutants of connexins Cx40 and Cx43 (Cx40E12S,E13G and Cx43D12S,K13G) in which the charged amino acids at positions 12 and 13 were replaced with serine and glycine as found in Cx32. HeLa, N2a and HEK293 cells were transfected and studied by immunochemistry and double whole-cell patch clamping. Immunoblotting confirmed production of the mutant proteins, and immuno-fluorescence localized them to punctuate distributions along appositional membranes. Cx40E12S,E13G and Cx43D12S,K13G formed homotypic gap junction channels that allowed intercellular passage of Lucifer Yellow and electrical current, but these channels exhibited negligible voltage-dependent gating properties. Unlike wild-type Cx40, Cx40E12S,E13G channels were insensitive to block by 2 mM spermine. Affinity purification of material solubilized by Triton X-100 from cells co-expressing mutant Cx43 or mutant Cx40 with wild-type Cx40, Cx43 or Cx26 showed that introducing the mutations did not affect the compatibility or incompatibility of these proteins for heteromeric mixing. Co-expression of Cx40E12S,E13G with wild-type Cx40 or Cx43 dramatically reduced voltage-dependent gating. Thus, whereas the charged amino acids at positions 12 and 13 of Cx40 or Cx43 are not required for gap junction assembly or the compatibility of oligomerization with each other or with Cx26, they strongly influence several physiological properties including those of heteromeric channels.
Differential actions of the proneural genes encoding Mash1 and neurogenins in Nurr1-induced dopamine neuron differentiation
Authors: Park Chang-Hwan , Kang Jin Sun , Kim Jae-Sang , Chung Seungsoo , Koh Jin-Young , Yoon Eun-Hye , Jo A. Young , Chang Mi-Yoon , Koh Hyun-Chul , Hwang SeJin , Suh-Kim Haeyoung , Lee Yong-Sung , Kim Kwang-Soo , Lee Sang-Hun
Published: May 2006

The steroid receptor-type transcription factor Nurr1 has a crucial role in the development of the mesencephalic dopamine (DA) neurons. Although ectopic expression of Nurr1 in cultured neural precursor cells is sufficient in establishing the DA phenotype, Nurr1-induced DA cells are morphologically and functionally immature, suggesting the necessity of additional factor(s) for full neuronal differentiation. In this study, we demonstrate that neurogenic basic helix-loop-helix (bHLH) factors Mash1, neurogenins (Ngns) and NeuroD play contrasting roles in Nurr1-induced DA neuronal differentiation. Mash1, but not Ngn2, spatially and temporally colocalized with aldehyde dehydrogenase 2 (AHD2), a specific midbrain DA neuronal progenitor marker, in the early embryonic ventral mesencephalon. Forced expression of Mash1 caused immature Nurr1-induced DA cells to differentiate into mature and functional DA neurons as judged by electrophysiological characteristics, release of DA, and expression of presynaptic DA neuronal markers. By contrast, atonal-related bHLHs, represented by Ngn1, Ngn2 and NeuroD, repressed Nurr1-induced expression of DA neuronal markers. Domain-swapping experiments with Mash1 and NeuroD indicated that the helix-loop-helix domain, responsible for mediating dimerization of bHLH transcription factors, imparts the distinct effect. Finally, transient co-transfection of the atonal-related bHLHs with Nurr1 resulted in an E-box-independent repression of Nurr1-induced transcriptional activation of a reporter containing Nurr1-binding element (NL3) as well as a reporter driven by the native tyrosine hydroxylase gene promoter. Taken together, these findings suggest that Mash1 contributes to the generation of DA neurons in cooperation with Nurr1 in the developing midbrain whereas atonal-related bHLH genes inhibit the process.
The chromodomain protein, Chromator, interacts with JIL-1 kinase and regulates the structure ofDrosophilapolytene chromosomes
Authors: Rath Uttama , Ding Yun , Deng Huai , Qi Hongying , Bao Xiaomin , Zhang Weiguo , Girton Jack , Johansen Jørgen , Johansen Kristen M.
Published: May 2006

In this study we have generated two new hypomorphic Chro alleles and analyzed the consequences of reduced Chromator protein function on polytene chromosome structure. We show that in Chro71/Chro612 mutants the polytene chromosome arms were coiled and compacted with a disruption and misalignment of band and interband regions and with numerous ectopic contacts connecting non-homologous regions. Furthermore, we demonstrate that Chromator co-localizes with the JIL-1 kinase at polytene interband regions and that the two proteins interact within the same protein complex. That both proteins are necessary and may function together is supported by the finding that a concomitant reduction in JIL-1 and Chromator function synergistically reduces viability during development. Overlay assays and deletion construct analysis suggested that the interaction between JIL-1 and Chromator is direct and that it is mediated by sequences in the C-terminal domain of Chromator and by the acidic region within the C-terminal domain of JIL-1. Taken together these findings indicate that Chromator and JIL-1 interact in an interband-specific complex that functions to establish or maintain polytene chromosome structure in Drosophila.
The ER-Golgi intermediate compartment (ERGIC): in search of its identity and function
Authors: Appenzeller-Herzog Christian , Hauri Hans-Peter
Published: May 2006

Protein traffic moving from the endoplasmic reticulum (ER) to the Golgi complex in mammalian cells passes through the tubulovesicular membrane clusters of the ER-Golgi intermediate compartment (ERGIC), the marker of which is the lectin ERGIC-53. The dynamic nature and functional role of the ERGIC have been debated for quite some time. In the most popular current view, the ERGIC clusters are mobile transport complexes that deliver secretory cargo from ER-exit sites to the Golgi. Recent live-cell imaging data revealing the formation of anterograde carriers from stationary ERGIC-53-positive membranes, however, suggest a stable compartment model in which ER-derived cargo is first shuttled from ER-exit sites to stationary ERGIC clusters in a COPII-dependent step and subsequently to the Golgi in a second vesicular transport step. This model can better accommodate previous morphological and functional data on ER-to-Golgi traffic. Such a stationary ERGIC would be a major site of anterograde and retrograde sorting that is controlled by coat proteins, Rab and Arf GTPases, as well as tethering complexes, SNAREs and cytoskeletal networks. The ERGIC also contributes to the concentration, folding, and quality control of newly synthesized proteins.
The satellite cell as a companion in skeletal muscle plasticity:currency, conveyance, clue, connector and colander
Authors: Anderson Judy E.
Published: May 2006

Satellite cells are companions to voluntary muscle fibres, and are named for their intimate positional or `satellite' relationship, as if revolving around fibres, like a satellite moon around the earth. Studies on the nature of at least some satellite cells, including their capabilities for self-renewal and for giving rise to multiple lineages in a stem cell-like function, are exploring the molecular basis of phenotypes described by markers of specialized function and gene expression in normal development,neuromuscular disease and aging. In adult skeletal muscle, the self-renewing capacity of satellite cells contributes to muscle growth, adaptation and regeneration. Muscle remodeling, such as demonstrated by changes in myofibre cross-sectional area and length, nerve and tendon junctions, and fibre-type distribution, occur in the absence of injury and provide broad functional and structural diversity among skeletal muscles. Those contributions to plasticity involve the satellite cell in at least five distinct roles, here described using metaphors for behaviour or the investigator's perspective. Satellite cells are the `currency' of muscle; have a `conveyance' role in adaptation by domains of cytoplasm along a myofibre; serve researchers, through a marker role, as `clues' to various activities of muscle; are `connectors' that physically, and through signalling and cell-fibre communications, bridge myofibres to the intra- and extra-muscular environment; and are equipped as metabolic and genetic filters or `colanders' that can rectify or modulate particular signals. While all these roles are still under exploration, each contributes to the plasticity of skeletal muscle and thence to the overall biology and function of an organism. The use of metaphor for describing these roles helps to clarify and scrutinize the definitions that form the basis of our understanding of satellite cell biology: the metaphors provide the construct for various approaches to detect or test the nature of satellite cell functions in skeletal muscle plasticity.
Plasticity in cell defence: access to and reactivity of critical protein residues and DNA response elements
Authors: Goldring Chris , Kitteringham Neil , Jenkins Rosalind , Copple Ian , Jeannin Jean-Francois , Park B. Kevin
Published: May 2006

Cellular and whole organ defence against pathogenic or chemical challenge is manifest as an adaptive response. Where appropriate, this may lead to induction of a cellular defence programme, thereby enhancing cell survival. When the challenge is overwhelming, the defence is breached and a switch is made to yield cell death, either by apoptosis or necrosis. Thus, a cell will defend itself where possible, but in extremis, it may recognise the futility of its resistance and allow itself to die. Transcription factor activation and access to the DNA regulatory elements that control a particular pattern of expression of defence genes is a major issue that may ultimately decide the fate of a cell in a changed environment. It is possible to visualise the access to the nucleus and to the genome, of paradigm gene loci or transcription factors, using a number of molecular techniques such as chromatin immunoprecipitation, in vivo footprinting and live/whole cell imaging. These methods are informative as to the array of transcription factors that may regulate a given gene, as well as the transitory nature of the transcriptional activation. The initial triggering of active transcription factor complexes typically occurs within the cytoplasm of the cell. Protein–protein interactions and signal transduction pathways,elucidated using a classical molecular genetics approach, have long been recognised as pivotal to the initial control of the levels and activity of transcription factors. We can now visualise modifications in critical residues of transcription factors and regulators during cellular response to chemical stress. These modifications may yield enhanced or repressed activity of transcription factors, they may be non-covalent or covalent, and they may occur in response to a variety of classes of chemicals. Such promiscuous signalling can provide plasticity in the cellular response to a wide array of chemical agents.
Letter: Influence of Experimental Conditions on Electrospray Ionization Mass Spectrometry of Ferrocenylalkylazoles
Authors: Skazov Roman S. , Nekrasov Yury S. , Kuklin Sergey A. , Simenel Alexander A.
Published: May 2006

The influence of experimental conditions on electrospray/ionization (ESI) mass spectra of ferrocene derivatives FcCH(R)Az (Fc=ñ5–C5H5–Fe–ñ5–C5H4; R=H, Az=benzimidazole; R=Ph, Az=2-methylimidazole) has been investigated. The spectra of all the compounds revealed [M]+·, products of its fragmentation [FcCHR]+ as well as products of ion/molecular interactions (protonated molecule [MH]+, binuclear ion [(FcCHR)2 Az]+, dimeric ion [M2]+· and its protonated form [M2H]+). Relative abundances of these ions appreciably (more than one order) depend on experimental conditions: analyte concentration, temperature of heated capillary, spray voltage, flow rate of mobile phase and polarity of solvents. Established correlations allow the selection of optimum experimental conditions for registration of ESI mass spectra, as required by the application. If an unknown compound is to be identified, it is necessary to operate by using polar solvents, small concentrations, low temperature of heated capillary, high spray voltage and flow rates. There are high-intensity binuclear and protonated dimeric ions in mass spectra under other conditions. These can give rise to the wrong interpretation of the structure of the investigated compound. At the same time, for the study of ion-molecular processes by ESI-MS, it is necessary to use concentrated samples in non-polar solvents. In this case, the dependence of reaction product yields on temperature and flow rate of the mobile phase must be investigated.
Supramolecular Clusters between Carbohydrates and Concave Pyridines. Detection in the Gas Phase by Resonance-Enhanced Multi-Photon Ionization Refectron Time-of-Fight Mass Spectrometry
Authors: Liebig Timo , Lüning Ulrich , Grotemeyer Jürgen
Published: May 2006

For the first time, the formation of supramolecular clusters between concave pyridines and different carbohydrates could be observed in the gas phase. The different clusters have been investigated by means of laser desorption into a supersonic beam followed by resonant multi-photon excitation yielding mass spectra with high intensity of the different clusters. These preliminary results open the way for investigating the hydrogen bonds in these compounds.
Synthesis and decay properties of superheavy elements
Authors: Oganessian Yuri
Published: May 2006

A fundamental outcome of modern nuclear theory is the prediction of the "island of stability" in the region of hypothetical superheavy elements. A significant enhancement in nuclear stability at approaching the closed shells with Z = 114 (possibly 120 and 122) and N = 184 is expected for the nuclei with large neutron excess. For this reason, for the synthesis of nuclei with Z = 112-116 and 118, we chose the reactions 238U, 242,244Pu, 243Am, 245,248Cm, and 249Cf + 48Ca, which are characterized by fusion products with a maximal neutron excess. The formation and decay properties of the heaviest nuclei were registered with the use of a gas-filled recoil separator installed at a 48Ca-beam of the heavy-ion cyclotron. The new nuclides mainly undergo sequential α-decay, which ends with spontaneous fission (SF). The total time of decay ranges from 0.5 ms to ~1 d, depending on the proton and neutron numbers in the synthesized nuclei. The atomic number of the new elements 115 and 113 was confirmed also by an independent radiochemical experiment based on the identification of the neutron-rich isotope 268Db (T
SF ~ 30 h), the final product in the chain of α-decays of the odd-odd parent nucleus 288115. The comparison of the decay properties of 29 new nuclides with Z = 104-118 and N = 162-177 gives evidence of the decisive influence of the structure of superheavy elements on their stability with respect to different modes of radioactive decay. The investigations connected with the search for superheavy elements in Nature are also presented.

The experiments were carried out at the Flerov Laboratory of Nuclear Reactions (JINR, Dubna) in collaboration with the Analytical and Nuclear Chemistry Division of the Lawrence Livermore National Laboratory (USA).
Stabilizing interfacial micellar aggregates by enhanced supramolecular interaction or surface polymerization
Authors: Song Bo , Wang Zhiqiang , Zhang Xi
Published: May 2006

This presentation describes the surface micelles formed by self-organization of amphiphilic molecules at the solid/liquid interface, and reviews the methods of stabilizing the surface micelles by enhancing the intermolecular interaction or introducing covalent bonds in self-assemblies. This type of work may provide new avenues for fabricating organic nanostructure materials, as well as possible applications arising from the mimicry of biomineralization processes.
Consolidation Yield Stress of Osaka-Bay Pleistocene Clay with Reference to Calcium Carbonate Contents
Authors: Imai G , Komatsu Y , Fukue M
Published: May 2006

Sea bottom has been used as landfill sites to dispose various types of waste and dredged materials. Therefore, the geotechnical properties of seabed are of great importance for the design and practice of reclamation projects. Marine clay layers are known to be geologically normally consolidated. Those clays, however, show pseudo-overconsolidation behavior with a consolidation yield stress pc larger than the in situ overburden pressure p0. As consolidation behavior of those clays under a load around pc is not normal but very complex, the prediction of possible settlement under loading is presently quite difficult. In this study, the Osaka-Bay Pleistocene clays were sampled and subjected to physical and mechanical tests. Based on previous studies, it is assumed in this paper that the disagreement between p0 and pc results from the cementation of marine soils, and that their cementation is mainly due to calcium carbonate. If the assumption made is valid, pc value of a clay sample of which calcium carbonates had been chemically dissolved must be equal to p0 value. In order to verify this assumption, experimental studies has been done. Carbonic-acid water of enough volume to dissolve the calcium carbonates in a clay sample was percolated without breaking fabric structure of the clay skeleton, and pc value of the sample was determined by the constant strain rate of consolidation test. The results showed a definite decrease of the pc value. Consequently, the pseudooverconsolidation ratio of the specimens decreased with the removal of calcium carbonates.
Benchmarking of PENTRAN-SSN Parallel Transport Code and FAST Preconditioning Algorithm Using the VENUS-2 MOX-Fueled Benchmark Problem
Authors: Longoni G , Haghighat A , Yi C , Sjoden GE
Published: May 2006

The discrete ordinates method (Sn) is the most widely used technique to obtain numerical solutions of the linear Boltzmann equation, and therefore to evaluate radiation fields and dose rates in nuclear devices. However, it is well known that this method suffers from slow convergence for problems characterized by optically thick media and scattering ratio close to unity. To address this issue we have developed a new preconditioning algorithm based on the even-parity simplified Sn (EP-SSN) equations. The new method is based on the flux acceleration simplified transport (FAST) algorithm which is implemented into the PENTRAN-SSN code system. The code system is designed for parallel computing architectures; PENTRAN-SSN features spatial, angular, and energy domain decomposition algorithms. The FAST preconditioner is parallelized with a spatial domain decomposition algorithm. In this paper, our objective is to test the performance of the new preconditioning system for a three-dimensional shielding calculation based on the VENUS-2 MOX-fueled benchmark problem, issued by OECD/NEA (Organization for Economic Co-operation and Development/Nuclear Energy Agency.
Lisfranc Ligament Injuries in Windsurfers
Authors: Mitani G , Hirose H , Nakamura Y , Shimpuku E , Minezaki T , Mochida J
Published: May 2006

Recently, due to evolution of equipment and techniques, ordinary-level windsurfers can attempt acrobatic activities that previously only high-level windsurfers could perform in stormy conditions. Moreover, many difficult aerial tricks have been developed by high-level windsurfers. Synchronously, “foot strap injuries” have increased, which affect the knee, ankle, and foot by twisting loads because the foot is unable to be released from the foot strap. Here we report three Lisfranc ligament injuries in windsurfers that had not been diagnosed appropriately at another medical institution. The cases of two professional, and one amateur windsurfer, all of whom sustained a sprain to the anterior foot when they failed to land properly following an aerial trick or during wave riding, are reported in this publication. Weightbearing anterior to posterior (AP) view radiographs were an important tool for the diagnosis of these Lisfranc ligament injuries which can easily be missed on nonweightbearing films. Surgical treatment was chosen for two cases and conservative treatment was chosen for the other. To allow the windsurfers to return successfully to competition, we devised a special cork insole inside a marine boot called the “Ninja.” Lisfranc Ligament injuries should be suspected as there are frequent foot injuries in windsurfers, and adequate treatment can enable the patients to return to competition successfully.