bluuebunny/crossref_metadata_2025 huggingface dataset:
Influenza Antiviral Resistance Testing in New York and Wisconsin, 2006 to 2008: Methodology and Surveillance Data
Authors: Laplante Jennifer M. , Marshall Steven A. , Shudt Matthew , Van Tam T. , Reisdorf Erik S. , Mingle Lisa A. , Shult Peter A. , St. George Kirsten
Published: March 2009

The need for effective influenza antiviral susceptibility surveillance methods has increased due to the emergence of near-universal adamantane resistance in influenza A/H3N2 viruses during the 2005-2006 season and the appearance of oseltamivir resistance in the influenza A/H1N1 virus subtype during the 2007-2008 season. The two classes of influenza antivirals, the neuraminidase inhibitors (NAIs) and the adamantanes, are well characterized, as are many mutations that can confer resistance to these drugs. Adamantane resistance is imparted mainly by a S31N mutation in the matrix gene, while NAI resistance can result from a number of mutations in the neuraminidase gene. During the 2007-2008 season, a neuraminidase mutation (H274Y) conferring resistance to the NAI oseltamivir emerged worldwide in the A/H1N1 virus subtype. Surveillance methodology and data from New York (NY) and Wisconsin (WI) for the 2006-2007 and 2007-2008 influenza seasons are presented. We used an existing pyrosequencing method (R. A. Bright et al., Lancet 366:1175-1181, 2005) and a modified version of this method for detection of adamantane resistance mutations. For NAI resistance mutation detection, we used a mutation-specific pyrosequencing technique and developed a neuraminidase gene dideoxy sequencing method. Adamantane resistance in the A/H3N2 virus samples was 100% for 2007-2008, similar to the 99.8% resistance nationwide as reported by the CDC. Adamantane resistance was found in only 1.2% of NY and WI A/H1N1 virus samples, compared to that found in 10.8% of samples tested nationwide as reported by the CDC. Influenza A/H1N1 virus H274Y mutants were found in 11.1% of NY samples for 2007-2008, a level comparable to the 10.9% nationwide level reported by the CDC; in contrast, mutants were found in 17.4% of WI samples. These results indicate the need for regional influenza antiviral surveillance.
Molecular Identification and Susceptibility ofTrichosporonSpecies Isolated from Clinical Specimens in Qatar: Isolation ofTrichosporon dohaenseTaj-Aldeen, Meis & Boekhout sp. nov
Authors: Taj-Aldeen Saad J. , Al-Ansari Nasser , El Shafei Sittana , Meis Jacques F. , Curfs-Breuker Ilse , Theelen Bart , Boekhout Teun
Published: March 2009

Trichosporonspecies have been reported as emerging pathogens and usually occur in severely immunocompromised patients. In the present work, 27 clinical isolates ofTrichosporonspecies were recovered from 27 patients. The patients were not immunocompromised, except for one with acute myeloid leukemia. Sequence analysis revealed the isolation ofTrichosporon dohaenseTaj-Aldeen, Meis & Boekhout sp. nov., with CBS 10761Tas the holotype strain, belonging to the Ovoides clade. In the D1-D2 large-subunit rRNA gene analysis,T. dohaenseis a sister species toT. coremiiforme, and in the internal transcribed spacer analysis, the species is basal to the other species of this clade. Molecular identification of the strains yielded 17T. asahii, 3T. inkin, 2T. japonicum, 2T. faecale, and 3T. dohaenseisolates. The former four species exhibited low MICs for five antifungal azoles but showed high MICs for amphotericin B.T. dohaensedemonstrated the lowest amphotericin B MIC (1 mg/liter). For the majority ofT. asahiiisolates, amphotericin B MICs were high (MIC at which 90% of isolates were inhibited [MIC90], ≥16 mg/liter), and except for fluconazole (MIC90, 8 mg/liter), the azole MICs were low: MIC90s were 0.5 mg/liter for itraconazole, 0.25 mg/liter for voriconazole, 0.25 mg/liter for posaconazole, and 0.125 mg/liter for isavuconazole. The echinocandins, caspofungin and anidulafungin, demonstrated no activity againstTrichosporonspecies.
Characterization of Methicillin-Resistant
Staphylococcus aureus
Isolates Collected in 2005 and 2006 from Patients with Invasive Disease: a Population-Based Analysis
Authors: Limbago Brandi , Fosheim Gregory E. , Schoonover Valerie , Crane Christina E. , Nadle Joelle , Petit Susan , Heltzel David , Ray Susan M. , Harrison Lee H. , Lynfield Ruth , Dumyati Ghinwa , Townes John M. , Schaffner William , Mu Yi , Fridkin Scott K.
Published: March 2009

This study characterizes 1,984 methicillin-resistant
Staphylococcus aureus
(MRSA) isolates collected in 2005 and 2006 from normally sterile sites in patients with invasive MRSA infection. These isolates represent a convenience sample of all invasive MRSA cases reported as part of the Active Bacterial Core surveillance system in eight states in the United States. The majority of isolates were from blood (83.8%), joints (4.1%), and bone (4.2%). Isolates were characterized by pulsed-field gel electrophoresis (PFGE); SCC
mec
typing; susceptibility to 15 antimicrobial agents; and PCR analysis of staphylococcal enterotoxin A (SEA) to SEH, toxic shock syndrome toxin 1, and Panton-Valentine leukocidin. Thirteen established PFGE types were recognized among these isolates, although USA100 and USA300 predominated, accounting for 53.2% and 31.4% of the isolates, respectively. As expected, isolates from hospital onset cases were predominantly USA100, whereas those from community-associated cases were predominantly USA300. USA100 isolates were diverse (Simpson's discriminatory index [DI] = 0.924); generally positive only for enterotoxin D (74.5%); and resistant to clindamycin (98.6%), erythromycin (99.0%), and levofloxacin (99.6%), in addition to β-lactam agents. USA300 isolates were less diverse (DI = 0.566), positive for Panton-Valentine leukocidin (96.3%), and resistant to erythromycin (94.1%) and, less commonly, levofloxacin (54.6%), in addition to β-lactam agents. This collection provides a reference collection of MRSA isolates associated with invasive disease, collected in 2005 and 2006 in the United States, for future comparison and ongoing studies.
Less-FrequentFusariumSpecies of Clinical Interest: Correlation between Morphological and Molecular Identification and Antifungal Susceptibility
Authors: Azor Mónica , Gené Josepa , Cano Josep , Manikandan Palanisamy , Venkatapathy Narendran , Guarro Josep
Published: March 2009

Forty-eightFusariumisolates morphologically identified as belonging to seven species of clinical interest (i.e.,Fusarium chlamydosporum,Fusarium dimerum,Fusarium incarnatum,Fusarium napiforme,Fusarium nygamai,Fusarium proliferatum, andFusarium sacchari) were characterized molecularly by the analysis of the sequences of the TUB region of the β-tubulin gene.F. chlamydosporumandF. dimerumwere the most genetically heterogeneous species. A high degree of correlation between the morphological and molecular identification was shown among the isolates studied. A table with the key morphological features for the identification of theseFusariumspecies is provided. The antifungal susceptibilities of theFusariumisolates to 11 antifungal drugs were tested; terbinafine was the most active drug against all the species tested with the exception ofF. incarnatum, for which amphotericin B was the most active.
Utility of the Pneumoslide Test in Identification of
Streptococcus pneumoniae
in Blood Cultures and Its Relation to Capsular Serotype
Authors: Chan Wilson W. , Lovgren Marguerite , Tyrrell Gregory J.
Published: March 2009

The performance of the Pneumoslide test for rapid identification of
Streptococcus pneumoniae
was evaluated when used directly on positive blood culture specimens. The sensitivity was 75.3%, and the specificity was 98.6%. Pneumoslide test performance accuracy varied depending on the pneumococcal serotype.
Mutations in Hepatitis C Virus E2 Located outside the CD81 Binding Sites Lead to Escape from Broadly Neutralizing Antibodies but Compromise Virus Infectivity
Authors: Keck Zhen-yong , Li Sophia H. , Xia Jinming , von Hahn Thomas , Balfe Peter , McKeating Jane A. , Witteveldt Jeroen , Patel Arvind H. , Alter Harvey , Rice Charles M. , Foung Steven K. H.
Published: March 2009

Broadly neutralizing antibodies are commonly present in the sera of patients with chronic hepatitis C virus (HCV) infection. To elucidate possible mechanisms of virus escape from these antibodies, retrovirus particles pseudotyped with HCV glycoproteins (HCVpp) isolated from sequential samples collected over a 26-year period from a chronically infected patient, H, were used to characterize the neutralization potential and binding affinity of a panel of anti-HCV E2 human monoclonal antibodies (HMAbs). Moreover, AP33, a neutralizing murine monoclonal antibody (MAb) to a linear epitope in E2, was also tested against selected variants. The HMAbs used were previously shown to broadly neutralize HCV and to recognize a cluster of highly immunogenic overlapping epitopes, designated domain B, containing residues that are also critical for binding of viral E2 glycoprotein to CD81, a receptor essential for virus entry. Escape variants were observed at different time points with some of the HMAbs. Other HMAbs neutralized all variants except for the isolate 02.E10, obtained in 2002, which was also resistant to MAb AP33. The 02.E10 HCVpp that have reduced binding affinities for all antibodies and for CD81 also showed reduced infectivity. Comparison of the 02.E10 nucleotide sequence with that of the strain H-derived consensus variant, H77c, revealed the former to have two mutations in E2, S501N and V506A, located outside the known CD81 binding sites. Substitution A506V in 02.E10 HCVpp restored binding to CD81, but its antibody neutralization sensitivity was only partially restored. Double substitutions comprising N501S and A506V synergistically restored 02.E10 HCVpp infectivity. Other mutations that are not part of the antibody binding epitope in the context of N501S and A506V were able to completely restore neutralization sensitivity. These findings showed that some nonlinear overlapping epitopes are more essential than others for viral fitness and consequently are more invariant during earlier years of chronic infection. Further, the ability of the 02.E10 consensus variant to escape neutralization by the tested antibodies could be a new mechanism of virus escape from immune containment. Mutations that are outside receptor binding sites resulted in structural changes leading to complete escape from domain B neutralizing antibodies, while simultaneously compromising viral fitness by reducing binding to CD81.
Comparison of Human and Rhesus Macaque T-Cell Responses Elicited by Boosting with NYVAC Encoding Human Immunodeficiency Virus Type 1 Clade C Immunogens
Authors: Mooij Petra , Balla-Jhagjhoorsingh Sunita S. , Beenhakker Niels , van Haaften Patricia , Baak Ilona , Nieuwenhuis Ivonne G. , Heidari Shirin , Wolf Hans , Frachette Marie-Joelle , Bieler Kurt , Sheppard Neil , Harari Alexandre , Bart Pierre-Alexandre , Liljeström Peter , Wagner Ralf , Pantaleo Giuseppe , Heeney Jonathan L.
Published: March 2009

Rhesus macaques (
Macaca mulatta
) have played a valuable role in the development of human immunodeficiency virus (HIV) vaccine candidates prior to human clinical trials. However, changes and/or improvements in immunogen quality in the good manufacturing practice (GMP) process or changes in adjuvants, schedule, route, dose, or readouts have compromised the direct comparison of T-cell responses between species. Here we report a comparative study in which T-cell responses from humans and macaques to HIV type 1 antigens (Gag, Pol, Nef, and Env) were induced by the same vaccine batches prepared under GMP and administered according to the same schedules in the absence and presence of priming. Priming with DNA (humans and macaques) or alphavirus (macaques) and boosting with NYVAC induced robust and broad antigen-specific responses, with highly similar Env-specific gamma interferon (IFN-γ) enzyme-linked immunospot assay responses in rhesus monkeys and human volunteers. Persistent cytokine responses of antigen-specific CD4
+
and CD8
+
T cells of the central memory as well as the effector memory phenotype, capable of simultaneously eliciting multiple cytokines (IFN-γ, interleukin 2, and tumor necrosis factor alpha), were induced. Responses were highly similar in humans and primates, confirming earlier data indicating that priming is essential for inducing robust NYVAC-boosted IFN-γ T-cell responses. While significant similarities were observed in Env-specific responses in both species, differences were also observed with respect to responses to other HIV antigens. Future studies with other vaccines using identical lots, immunization schedules, and readouts will establish a broader data set of species similarities and differences with which increased confidence in predicting human responses may be achieved.
Major Histocompatibility Complex Haplotype Determines hsp70-Dependent Protection against Measles Virus Neurovirulence
Authors: Carsillo Thomas , Carsillo Mary , Traylor Zachary , Rajala-Schultz Päivi , Popovich Phillip , Niewiesk Stefan , Oglesbee Michael
Published: March 2009

In vitro studies show that hsp70 promotes gene expression for multiple viral families, although there are few reports on the in vivo significance of virus-hsp70 interaction. Previously we showed that hsp70-dependent stimulation of Edmonston measles virus (Ed MeV) transcription caused an increased cytopathic effect and mortality in transgenic hsp70-overexpressing C57BL/6 mice (H-2b). The response to MeV infection is influenced by the major histocompatibility complex haplotype;H-2dmice are resistant to brain infection due to robust antiviral immune responses, whereasH-2bmice are susceptible due to deficiencies in this response. We therefore tested the hypothesis that the outcome of MeV-hsp70 interaction may be dependent upon the hostH-2haplotype. The impact of selective neuronal hsp70 overexpression on Ed MeV brain infection was tested with congenic C57BL/10H-2dneonatal mice. In this context, hsp70 overexpression conferred complete protection against virus-induced mortality, compared to >30% mortality in nontransgenic mice. Selective depletion of T-cell populations showed that transgenic mice exhibit a diminished reliance on T cells for protection. Brain transcript analysis indicated enhanced innate immune activation and signaling through Toll-like receptors 2 and 4 at early times postinfection for transgenic infected mice relative to those for nontransgenic infected mice. Collectively, results suggest that hsp70 can enhance innate antiviral immunity through Toll-like receptor signaling, supporting a protective role for physiological responses that enhance tissue levels of hsp70 (e.g., fever), and that theH-2haplotype determines the effectiveness of this response.
Composite intestinal-type adenocarcinoma and small cell carcinoma of sinonasal tract
Authors: Jain R , Gramigna V , Sanchez-Marull R , Perez-Ordoñez B
Published: March 2009

Background and aims:

Sinonasal intestinal-type adenocarcinomas (ITACs) are rare neoplasms resembling intestinal adenocarcinomas. Although several studies have documented neuroendocrine differentiation in ITACs, the combination of ITAC and small cell carcinoma has not been previously described in detail. The aim of this report is to detail the histopathological and immunohistochemical characteristics of two cases of composite ITAC with small cell carcinoma.

Methods:

Two cases of composite ITAC with small cell carcinoma were routinely processed, and representative sections were stained with CAM5.2, AE1:AE3, keratin 7, keratin 20, keratin 19, CDX-2, p63, villin, chromogranin, synaptophysin and CD56.

Results:

One tumour consisted of a mixed-type ITAC showing colonic-type and poorly differentiated adenocarcinoma with foci of “signet-ring” cells combined with small cell carcinoma. Both components stained positively with CAM5.2, AE1:AE3, CK7, CK20 and CK19, whereas only the small cell carcinoma expressed synaptophysin and CD56. Both components stained negatively with CDX-2, villin, CD99 and p63. The “signet-ring” cells stained positively with chromogranin and synaptophysin. The second tumour showed a papillary-type ITAC combined with a small cell carcinoma. The adenocarcinoma and small cell carcinoma stained positively with CAM5.2, AE1:AE3, CK7, CK19 and CK20. Only the adenocarcinoma was CDX-2 positive, whereas the small cell carcinoma expressed CD56 and synaptophysin.

Conclusions:

The two components of the combined ITACs and neuroendocrine small cell carcinoma show significant immunohistochemical overlap, supporting a common origin. The occurrence of a distinct neuroendocrine carcinoma combined with ITACs expands the histopathological spectrum of these tumours.
SELF-ORGANIZED CRITICALITY IN A WEIGHTED EARTHQUAKE MODEL
Authors: ZHANG GUI-QING , WANG LIN , CHEN TIAN-LUN
Published: March 2009

A weighted scale-free OFC model improving the redistribution rule of the original model has been introduced. Our model displays self-organized criticality behaviors with different network parameters, and the average earthquake size has been introduced to show the different effects of these parameters. Transient and oscillatory activity have been detected based on our weighted network, and the transient time increases with decreasing dissipative parameter.
STUDY OF FOLDING BEHAVIORS OF A SIX-HELIX PROTEIN BY ab initio MOLECULAR DYNAMICS FOLDING SIMULATIONS OF UNRES
Authors: HE YI , ZHOU RUI , XIAO YI
Published: March 2009

In this paper, we employ united-residue (UNRES) approach to study folding processes of a six-helix protein domain (the C-terminal domain of Ku86 protein, PDB ID: 1Q2Z). We simulated forty-eight 110-ns independent molecular dynamics trajectories with UNRES starting from extended conformations for this protein. The protein domain successfully folds into its native state and the results show that its folding process is relatively simple: first, the secondary structures form very fast with the hydrophobic collapse, then helix pairs form, and finally these pairs assemble into the tertiary structure. We also find the first-half (the first three helices) and last-half (the last three helices) parts of this protein domain can fold into their native conformations independently and this suggests that this protein may be evolved from smaller polypeptide or protein.
CO-EVOLUTION OF OPINION AND STRATEGY IN PERSUASION DYNAMICS: AN EVOLUTIONARY GAME THEORETICAL APPROACH
Authors: DING FEI , LIU YUN , LI YONG
Published: March 2009

In this paper, a new model of opinion formation within the framework of evolutionary game theory is presented. The model simulates strategic situations when people are in opinion discussion. Heterogeneous agents adjust their behaviors to the environment during discussions, and their interacting strategies evolve together with opinions. In the proposed game, we take into account payoff discount to join a discussion, and the situation that people might drop out of an unpromising game. Analytical and emulational results show that evolution of opinion and strategy always tend to converge, with utility threshold, memory length, and decision uncertainty parameters influencing the convergence time. The model displays different dynamical regimes when we set differently the rule when people are at a loss in strategy.
PRISONER'S DILEMMA GAMES WITH SOME TROUBLEMAKERS IN A RANDOM NETWORK
Authors: YANG ZHI-XUAN , WANG XUE-QING , HUANG XIAO-LI , BU SHOU-LIANG
Published: March 2009

We further study the competition among loner, cooperative and defective strategies by considering an evolutionary prisoner's dilemma (PD) game with some troublemakers in the random network by means of Monte Carlo simulations. It can be observed that the frequency of cooperators (fc) decreases with increasing of loners' (e) and defectors' payoffs (b). In particular, fc has a sharp decline when the loners' payoffs approximate 1.0. In addition, we find that introduction of troublemaker strategies prevents the uniform defection in the spatial evolutionary PD games for large b values and small e values. In practice, it also prevents cooperative strategies and defective strategies from vanishing for large e values.
Essential environmental cues from the satellite cell niche: optimizing proliferation and differentiation
Authors: Boonen K. J. M. , Rosaria-Chak K. Y. , Baaijens F. P. T. , van der Schaft D. W. J. , Post M. J.
Published: March 2009

The use of muscle progenitor cells (MPCs) for regenerative medicine has been severely compromised by their decreased proliferative and differentiative capacity after being cultured in vitro. We hypothesized the loss of pivotal niche factors to be the cause. Therefore, we investigated the proliferative and differentiative response of passage 0 murine MPCs to varying substrate elasticities and protein coatings and found that proliferation was influenced only by elasticity, whereas differentiation was influenced by both elasticity and protein coating. A stiffness of 21 kPa optimally increased the proliferation of MPCs. Regarding differentiation, we demonstrated that fusion of MPCs into myotubes takes place regardless of elasticity. However, ongoing maturation with cross-striations and contractions occurred only on elasticities higher than 3 kPa. Furthermore, maturation was fastest on poly-d-lysine and laminin coatings.
Properties of easily releasable myofilaments: are they the first step in myofibrillar protein turnover?
Authors: Neti Girija , Novak Stefanie M. , Thompson Valery F. , Goll Darrel E.
Published: March 2009

Myofibrillar proteins must be removed from the myofibril before they can be turned over metabolically in functioning muscle cells. It is uncertain how this removal is accomplished without disruption of the contractile function of the myofibril. It has been proposed that the calpains could remove the outer layer of filaments from myofibrils as a first step in myofibrillar protein turnover. Several studies have found that myofilaments can be removed from myofibrils by trituration in the presence of ATP. These easily releasable myofilaments (ERMs) were proposed to be intermediates in myofibrillar protein turnover. It was unclear, however, whether the ERMs were an identifiable entity in muscle or whether additional trituration would remove more myofilaments until the myofibril was gone and whether calpains could release ERMs from intact myofibrils. The present study shows that few ERMs could be obtained from the residue after the first removal of ERMs, and the yield of ERMs from well-washed myofibrils was reduced, probably because some ERMs had been removed by the washing process. Mild calpain treatment of myofibrils released filaments that had a polypeptide composition and were ultrastructurally similar to ERMs. The yield of calpain-released ERMs was two- to threefold greater than the normal yield. Hence, ERMs are an identifiable entity in myofibrils, and calpain releases filaments that are similar to ERMs. The role of ERMs in myofibrillar protein turnover is unclear, because only filaments on the surface of the myofibril would turn over, and changes in myofibrillar protein isoforms during development could not occur via the ERM mechanism.
Pharmacological properties of a pore induced by raising intracellular Ca2+
Authors: Faria R.X. , Reis R.A.M. , Casabulho C.M. , Alberto A.V.P. , de Farias F.P. , Henriques-Pons A. , Alves L.A.
Published: March 2009

Recent studies on the P2X7receptor in 2BH4 cells and peritoneal macrophages have demonstrated that the raise in intracellular Ca2+concentration induces a pore opening similar to P2X7receptor pore. Herein, we have investigated whether the pore activated by the elevation of intracellular Ca2+concentration is associated to P2X7receptor. Using patch clamp in cell attached, whole cell configuration, and dye uptake, we measured the pore opening in cell types that express the P2X7receptor (2BH4 cells and peritoneal macrophages) and in cells that do not express this receptor (HEK-293 and IT45-RI cells). In 2BH4 cells, the stimulation with ionomycin (5–10 μM) increased intracellular free Ca2+concentration and induced pore formation with conductance of 421 ± 14 pS, half-time ( t½) for ethidium bromide uptake of 118 ± 17 s, and t½for Lucifer yellow of 122 ± 11 s. P2X7receptor antagonists did not block these effects. Stimulation of HEK-293 and IT45-RI cells resulted in pore formation with properties similar to those found for 2BH4 cells. Connexin hemichannel inhibitors (carbenoxolone and heptanol) also did not inhibit the pore-induced effect following the increase in intracellular Ca2+concentration. However, 5-( N, N-hexamethylene)-amiloride, a P2X7receptor pore blocker, inhibited the induced pore. Moreover, intracellular signaling modulators, such as calmodulin, phospholipase C, mitogen-activated protein kinase, and cytoskeleton components were important for the pore formation. Additionally, we confirmed the results obtained for electrophysiology by using the flow cytometry, and we discarded the possibility of cellular death induced by raising intracellular Ca2+at the doses used by using lactate dehydrogenase release assay. In conclusion, increased concentration in intracellular Ca+2induces a novel membrane pore pharmacologically different from the P2X7associated pore and hemigap-junction pore.
The arginine metabolite agmatine protects mitochondrial function and confers resistance to cellular apoptosis
Authors: Arndt Mary Ann , Battaglia Valentina , Parisi Eva , Lortie Mark J. , Isome Masato , Baskerville Christopher , Pizzo Donald P. , Ientile Riccardo , Colombatto Sebastiano , Toninello Antonio , Satriano Joseph
Published: March 2009

Agmatine, an endogenous metabolite of arginine, selectively suppresses growth in cells with high proliferative kinetics, such as transformed cells, through depletion of intracellular polyamine levels. In the present study, we depleted intracellular polyamine content with agmatine to determine if attrition by cell death contributes to the growth-suppressive effects. We did not observe an increase in necrosis, DNA fragmentation, or chromatin condensation in Ha-Ras-transformed NIH-3T3 cells administered agmatine. In response to Ca2+-induced oxidative stress in kidney mitochondrial preparations, agmatine demonstrated attributes of a free radical scavenger by protecting against the oxidation of sulfhydryl groups and decreasing hydrogen peroxide content. The functional outcome was a protective effect against Ca2+-induced mitochondrial swelling and mitochondrial membrane potential collapse. We also observed decreased expression of proapoptotic Bcl-2 family members and of execution caspase-3, implying antiapoptotic potential. Indeed, we found that apoptosis induced by camptothecin or 5-fluorourocil was attenuated in cells administered agmatine. Agmatine may offer an alternative to the ornithine decarboxylase inhibitor difluoromethyl ornithine for depletion of intracellular polyamine content while avoiding the complications of increasing polyamine import and reducing the intracellular free radical scavenger capacity of polyamines. Depletion of intracellular polyamine content with agmatine suppressed cell growth, yet its antioxidant capacity afforded protection from mitochondrial insult and resistance to cellular apoptosis. These results could explain the beneficial outcomes observed with agmatine in models of injury and disease.
Ion transport across CF and normal murine olfactory and ciliated epithelium
Authors: Grubb B. R. , Rogers T. D. , Boucher R. C. , Ostrowski L. E.
Published: March 2009

The nasal epithelium of the cystic fibrosis (CF) mouse has been used extensively in CF research because it exhibits ion transport defects similar to those of human CF airways. This tissue is composed of ∼50% olfactory (OE) and ∼50% ciliated epithelium (CE), and on the basis of previous observations, we hypothesized that a significant fraction of the bioelectric signals from murine nasal tissue may arise from OE rather than CE, while CE is the target tissue for CF gene therapy. We compared the bioelectric properties of isolated OE from the nasal cavity and CE from the nasopharynx in Ussing chamber studies. Hyperabsorption of Na+ [amiloride response; CF vs. wild type (WT)] was ∼7.5-fold greater in the OE compared with the CE. The forskolin response in native tissues did not reliably distinguish genotypes, likely due to a cyclic nucleotide-gated cation conductance in OE and a calcium-mediated Cl− conductance in CE. By potential difference assay, hyperabsorption of Na+ (CF vs. WT) and the difference in response to apical 0 Cl− buffer (CF vs. WT) were ∼2-fold greater in the nasal cavity compared with the nasopharynx. Our studies demonstrate that in the CF mouse, both the hyperabsorption of Na+ and the Cl− transport defect are of larger magnitude in the OE than in the CE. Thus, while the murine CF nasal epithelium is a valuable model for CF studies, the bioelectrics are likely dominated by the signals from the OE, and assays of the nasopharynx may be more specific for studying the ciliated epithelium.
Regulation of intestinal Cl−/HCO3− exchanger SLC26A3 by intracellular pH
Authors: Hayashi Hisayoshi , Suruga Kazuhito , Yamashita Yukari
Published: March 2009

SLC26A3, a Cl−/HCO3− exchanger, is highly expressed in intestinal epithelial cells, and its mutations cause congenital chloride diarrhea. This suggests that SLC26A3 plays a key role in NaCl absorption in the intestine. Electroneutral NaCl absorption in the intestine is mediated by functional coupling of the Na+/H+ exchanger and Cl−/HCO3− exchanger. It is proposed that the coupling of these exchangers may occur as a result of indirect linkage by changes of intracellular pH (pHi). We therefore investigated whether SLC26A3 is regulated by pHi. We generated a hemagglutinin epitope-tagged human SLC26A3 construct and expressed it in Chinese hamster ovary cells. Transport activities were measured with a fluorescent chloride-sensitive dye dihydro-6-methoxy- N-ethylquinolinium iodide (diH-MEQ). pHi was clamped at a range of values from 6.0 to 7.4. We monitored the transport activity of SLC26A3 by reverse mode of Cl−/HCO3− and Cl−/NO3− exchange. None of these exchange modes induced membrane potential changes. At constant external pH 7.4, Cl−/HCO3− exchange was steeply inhibited with pHi decrease between 7.3 and 6.8 as opposed to thermodynamic prediction. In contrast, however, Cl−/NO3− exchange was essentially insensitive to pHi within physiological ranges. We also characterized the pHi dependency of COOH-terminal truncation mutants. Removal of the entire COOH-terminal resulted in decrease of the transport activity but did not noticeably affect pHi sensitivity. These results suggest that Cl−/HCO3− exchange mode of human SLC26A3 is controlled by a pH-sensitive intracellular modifier site, which is likely in the transmembrane domain. These observations raise the possibility that SLC26A3 activity may be regulated via Na+/H+ exchanger 3 (NHE3) through the alteration of pHi under physiological conditions.
A skeletal muscle model of extreme hypertrophic growth reveals the influence of diffusion on cellular design
Authors: Hardy Kristin M. , Dillaman Richard M. , Locke Bruce R. , Kinsey Stephen T.
Published: March 2009

Muscle fibers that power swimming in the blue crab Callinectes sapidus are <80 μm in diameter in juveniles but grow hypertrophically, exceeding 600 μm in adults. Therefore, intracellular diffusion distances become progressively greater as the animals grow and, in adults, vastly exceed those in most cells. This developmental trajectory makes C. sapidus an excellent model for characterization of the influence of diffusion on fiber structure. The anaerobic light fibers, which power burst swimming, undergo a prominent shift in organelle distribution with growth. Mitochondria, which require O2and rely on the transport of small, rapidly diffusing metabolites, are evenly distributed throughout the small fibers of juveniles, but in the large fibers of adults they are located almost exclusively at the fiber periphery where O2concentrations are high. Nuclei, which do not require O2, but rely on the transport of large, slow-moving macromolecules, have the inverse pattern: they are distributed peripherally in small fibers but are evenly distributed across the large fibers, thereby reducing diffusion path lengths for large macromolecules. The aerobic dark fibers, which power endurance swimming, have evolved an intricate network of cytoplasmically isolated, highly perfused subdivisions that create the short diffusion distances needed to meet the high aerobic ATP turnover demands of sustained contraction. However, fiber innervation patterns are the same in the dark and light fibers. Thus the dark fibers appear to have disparate functional units for metabolism (fiber subdivision) and contraction (entire fiber). Reaction-diffusion mathematical models demonstrate that diffusion would greatly constrain the rate of metabolic processes without these developmental changes in fiber structure.
Regulation of GLUT4 expression in denervated skeletal muscle
Authors: Jensen Ellis B. , Zheng Donghai , Russell Robert A. , Bassel-Duby Rhonda , Williams R. Sanders , Olson Ann Louise , Dohm G. Lynis
Published: March 2009

Denervation by sciatic nerve resection causes decreased muscle glucose transporter 4 (GLUT4) expression, but little is known about the signaling events that cause this decrease. Experiments were designed to test the hypothesis that decreased GLUT4 expression in denervated muscle occurs because of decreased calcium/CaMK activity, which would then lead to decreased activation of the transcription factors myocyte enhancer factor 2 (MEF2) and GLUT4 enhancer factor (GEF), which are required for normal GLUT4 expression. GLUT4 mRNA was elevated in mice expressing constitutively active CaMK isoform IV (CaMKIV) and decreased by denervation. Denervation decreased GEF binding to the promoter and the content of GEF in the nucleus, but there was no change in either MEF2 binding or MEF2 protein content. Expression of a MEF2-dependent reporter gene did not change in denervated skeletal muscle. To determine the domains of the GLUT4 promoter that respond to denervation, transgenic mice expressing the chloramphenicol acetyl transferase (CAT) reporter gene driven by different lengths of the human GLUT4 promoter were denervated. Using several different promoter/reporter gene constructs, we found that all areas of the GLUT4 promoter were truncated or missing, except for the MEF2 binding domain and the basal promoter. All of the GLUT4 promoter/CAT reporter constructs evaluated responded normally to denervation. Our data lead us to conclude that decreased CaMK activity is not the reason for decreased GLUT4 content in denervated muscle and that negative control of GLUT4 expression is not mediated through the MEF2 or GEF-binding domains. These findings indicate that withdrawal of a GEF- or MEF2-dependent signal is not likely a major determinant of the denervation effect on GLUT4 expression. Thus, the response to denervation may be mediated by other elements present in the basal promoter of the GLUT4 gene.
Modulation of Presaccadic Activity in the Frontal Eye Field by the Superior Colliculus
Authors: Berman Rebecca A. , Joiner Wilsaan M. , Cavanaugh James , Wurtz Robert H.
Published: March 2009

A cascade of neuronal signals precedes each saccadic eye movement to targets in the visual scene. In the cerebral cortex, this neuronal processing culminates in the frontal eye field (FEF), where neurons have bursts of activity before the saccade. This presaccadic activity is typically considered to drive downstream activity in the intermediate layers of the superior colliculus (SC), which receives direct projections from FEF. Consequently, the FEF activity is thought to be determined solely by earlier cortical processing and unaffected by activity in the SC. Recent evidence of an ascending path from the SC to FEF raises the possibility, however, that presaccadic activity in the FEF may also depend on input from the SC. Here we tested this possibility by recording from single FEF neurons during the reversible inactivation of SC. Our results indicate that presaccadic activity in the FEF does not require SC input: we never observed a significant reduction in FEF presaccadic activity when the SC was inactivated. Unexpectedly, in a third of experiments, SC inactivation elicited a significant increase in FEF presaccadic activity. The passive visual response of FEF neurons, in contrast, was virtually unaffected by inactivation of the SC. These findings show that presaccadic activity in the FEF does not originate in the SC but nevertheless may be influenced by modulatory signals ascending from the SC.
Spatial and Effector Processing in the Human Parietofrontal Network for Reaches and Saccades
Authors: Beurze S. M. , de Lange F. P. , Toni I. , Medendorp W. P.
Published: March 2009

It is generally accepted that interactions between parietal and frontal cortices subserve the visuomotor processing for eye and hand movements. Here, we used a sequential-instruction paradigm in 3-T functional MRI to test the processing of effector and spatial signals, as well as their interaction, as a movement is composed and executed in different stages. Subjects prepared either a saccade or a reach following two successive visual instruction cues, presented in either order. One cue instructed which effector to use (eyes, right hand); the other signaled the spatial goal (leftward vs. rightward target location) of the movement. During the first phase of the prepared movement, after cueing of either goal or effector information, we found significant spatial goal selectivity but no effector specificity along the parietofrontal network. During the second phase of the prepared movement, when both goal and effector information were available, we found a large overlap in the neural circuitry involved in the planning of eye and hand movements. Gradually distributed along this network, we observed clear spatial goal selectivity and limited, but significant, effector specificity. Regions in the intraparietal sulcus and the dorsal premotor cortex were selective to both goal location and motor effector. Taken together, our results suggest that the relative weight of spatial goal and effector selectivity changes along the parietofrontal network, depending on the status of the movement plan.
Wiener-Volterra Characterization of Neurons in Primary Auditory Cortex Using Poisson-Distributed Impulse Train Inputs
Authors: Pienkowski Martin , Shaw Greg , Eggermont Jos J.
Published: March 2009

An extension of the Wiener-Volterra theory to a Poisson-distributed impulse train input was used to characterize the temporal response properties of neurons in primary auditory cortex (AI) of the ketamine-anesthetized cat. Both first- and second-order “Poisson-Wiener” (PW) models were tested on their predictions of temporal modulation transfer functions (tMTFs), which were derived from extracellular spike responses to periodic click trains with click repetition rates of 2–64 Hz. Second-order (i.e., nonlinear) PW fits to the measured tMTFs could be described as very good in a majority of cases (e.g., predictability ≥80%) and were almost always superior to first-order (i.e., linear) fits. In all sampled neurons, second-order PW kernels showed strong compressive nonlinearities (i.e., a depression of the impulse response) but never expansive nonlinearities (i.e., a facilitation of the impulse response). In neurons with low-pass tMTFs, the depression decayed exponentially with the interstimulus lag, whereas in neurons with band-pass tMTFs, the depression was typically double-peaked, and the second peak occurred at a lag that correlated with the neuron's best modulation frequency. It appears that modulation-tuning in AI arises in part from an interplay of two nonlinear processes with distinct time courses.
Single‐Commodity Vehicle Routing Problem with Pickup and Delivery Service
Authors: Martinovic Goran , Aleksi Ivan , Baumgartner Alfonzo
Published: March 2009

We present a novel variation of the vehicle routing problem (VRP). Single commodity cargo with pickup and delivery service is considered. Customers are labeled as either cargo sink or cargo source, depending on their pickup or delivery demand. This problem is called a single commodity vehicle routing problem with pickup and delivery service (1‐VRPPD). 1‐VRPPD deals with multiple vehicles and is the same as the
single‐commodity traveling salesman problem (1‐PDTSP) when the number of vehicles is equal to 1.
Since 1‐VRPPD specializes VRP, it is 𝒩𝒫 hard in the strong sense. Iterative modified simulated annealing (IMSA) is presented along with greedy random‐based initial solution algorithm. IMSA provides a good approximation to the global optimum in a large search space. Experiment is done for the instances with different number of customers and their demands. With respect to average values of IMSA execution times, proposed method is appropriate for practical applications.
Perioperative and Oncological Outcome of Laparoscopic Resection of Gastrointestinal Stromal Tumour (GIST) of the Stomach
Authors: Ronellenfitsch Ulrich , Staiger Wilko , Kähler Georg , Ströbel Philipp , Schwarzbach Matthias , Hohenberger Peter
Published: March 2009

Background. Surgery remains the only curative treatment for gastrointestinal stromal tumour (GIST). Resection needs to ensure tumour-free margins while lymphadenectomy is not required. Thus, partial gastric resection is the treatment of choice for small gastric GISTs. Evidence on whether performing resection laparoscopically compromises outcome is limited. Methods. We compiled patients undergoing laparoscopic resection of suspected gastric GIST between 2003 and 2007. Follow-up was performed to obtain information on tumour recurrence. Results. Laparoscopic resection with free margins was performed in 21/22 patients. Histology confirmed GIST in 17 cases, 4 tumours were benign neoplasms. Median operation time and postoperative stay for GIST patients were 130 (range 80–201) mins and 7 (range 5–95) days. Two patients experienced stapler line leakage necessitating surgical revision. After median follow-up of 18 (range 1–53) months, no recurrence occurred. Conclusions. Laparoscopic resection of gastric GISTs yields good perioperative outcomes. Oncologic outcome needs to be assessed with longer follow-up. For posterior lesions, special precaution is needed. Laparoscopic resection could become standard for circumscribed gastric GISTs if necessary precautions for oncological procedures are observed.
Effect of Microwave Radiation on Enzymatic and Chemical Peptide Bond Synthesis on Solid Phase
Authors: Basso Alessandra , Sinigoi Loris , Gardossi Lucia , Flitsch Sabine
Published: March 2009

Peptide bond synthesis was performed on PEGA beads under microwave radiations. Classical chemical coupling as well as thermolysin catalyzed synthesis was studied, and the effect of microwave radiations on reaction kinetics, beads' integrity, and enzyme activity was assessed. Results demonstrate that microwave radiations can be profitably exploited to improve reaction kinetics in solid phase peptide synthesis when both chemical and biocatalytic strategies are used.
Perceptually Valid Facial Expressions for Character‐Based Applications
Authors: Arya Ali , DiPaola Steve , Parush Avi
Published: March 2009

This paper addresses the problem of creating facial expression of mixed emotions in a perceptually valid way. The research has been done in the context of a “game‐like” health and education applications aimed at studying social competency and facial expression awareness in autistic children as well as native language learning, but the results can be applied to many other applications such as games with need for dynamic facial expressions or tools for automating the creation of facial animations. Most existing methods for creating facial expressions of mixed emotions use operations like averaging to create the combined effect of two universal emotions. Such methods may be mathematically justifiable but are not necessarily valid from a perceptual point of view. The research reported here starts by user experiments aiming at understanding how people combine facial actions to express mixed emotions, and how the viewers perceive a set of facial actions in terms of underlying emotions. Using the results of these experiments and a three‐dimensional emotion model, we associate facial actions to dimensions and regions in the emotion space, and create a facial expression based on the location of the mixed emotion in the three‐dimensional space. We call these regionalized facial actions “facial expression units.”
Fixed Points of Maps of a Nonaspherical Wedge
Authors: Kim Seung Won , Brown Robert F. , Ericksen Adam , Khamsemanan Nirattaya , Merrill Keith
Published: March 2009

Let "Equation missing" be a finite polyhedron that has the homotopy type of the wedge of the projective plane and the circle. With the aid of techniques from combinatorial group theory, we obtain formulas for the Nielsen numbers of the selfmaps of "Equation missing".
Software-Defined Radio Demonstrators: An Example and Future Trends
Authors: Farrell Ronan , Sanchez Magdalena , Corley Gerry
Published: March 2009

Software-defined radio requires the combination of software-based signal processing and the enabling hardware components. In this paper, we present an overview of the criteria for such platforms and the current state of development and future trends in this area. This paper will also provide details of a high-performance flexible radio platform called the maynooth adaptable radio system (MARS) that was developed to explore the use of software-defined radio concepts in the provision of infrastructure elements in a telecommunications application, such as mobile phone basestations or multimedia broadcasters.
Electric and Adsorption Characteristics of Nanocrystalline V‐(N, He) Coatings
Authors: Guglya Alexey G. , Kolobrodov Viktor G. , Vasilenko Ruslan L.
Published: March 2009

This paper studies the structure, temperature dependences of electric resistance, and adsorption properties of nanoporous three‐component V‐(N, He) coatings. The coatings were produced using the technique of ion beam assisted deposition, in particular, deposition of vanadium onto a titanium substrate simultaneously bombarding it with N2 + He ions of 30 keV. It is shown, in contrast to V‐N composites that have negative TCR (temperature coefficient of resistance), that the V‐(N, He) coatings have negative TCR only in the temperature range of 250 to 350 ∘C. A specific surface of pores and adsorption characteristics of V‐(N, He) composites depend on preliminary treatment of a titanium surface. A coating deposited onto an untreated substrate has specific surface of 25.5 m2/g. The preliminary irradiation of titanium with N2 + He beam up to a dose of 6 × 1017 ion/cm2 provides the increase in surface area up to 57.6 m2/g. The preliminary ion bombardment provides a considerable increase in hydrogen adsorption capacity of coatings. Especially, such impact is noticeable at the room temperature, when the amount of hydrogen absorbed by a coating that was applied onto a treated surface is more than three times of that absorbed by a coating that was deposited onto nonexposed titanium.