bluuebunny/crossref_metadata_2025 huggingface dataset:
Epstein-Barr Virus Latent Membrane Protein 1 Represses DNA Repair through the PI3K/Akt/FOXO3a Pathway in Human Epithelial Cells
Authors: Chen Yi-Ren , Liu Ming-Tsan , Chang Yu-Ting , Wu Chung-Chun , Hu Chi-Yuan , Chen Jen-Yang
Published: June 2008

Latent membrane protein 1 (LMP1), an Epstein-Barr virus (EBV) oncoprotein, mimics a constitutively activated tumor necrosis factor receptor and activates various signaling pathways, including phosphatidylinositol 3-kinase (PI3K)/Akt. LMP1 is essential for EBV-mediated B-cell transformation and is sufficient to transform several cell lines. Cellular transformation has been associated strongly with genomic instability, while DNA repair plays an important role in maintaining genomic stability. Previously, we have shown that LMP1 represses DNA repair by the C-terminal activating region 1 (CTAR1) in human epithelial cells. In the present study, we demonstrate that the PI3K/Akt pathway is required for LMP1-mediated repression of DNA repair. Through the LMP1/PI3K/Akt pathway, FOXO3a, which can induce DNA repair, is inactivated because of phosphorylation and relocalization. Expression of a constitutively active FOXO3a mutant can rescue LMP1-mediated repression of DNA repair. Furthermore, LMP1 can decrease the expression of DNA damage-binding protein 1 (DDB1), which functions in nucleotide excision repair, through the PI3K/Akt/FOXO3a pathway. LMP1-mediated repression of DNA repair is restored by DDB1, although only partially. These results suggest that LMP1 triggers the PI3K/Akt pathway to inactivate FOXO3a and decrease DDB1, which can lead to repression of DNA repair and may contribute to genomic instability in human epithelial cells.
Autologous Neutralizing Humoral Immunity and Evolution of the Viral Envelope in the Course of Subtype B Human Immunodeficiency Virus Type 1 Infection
Authors: Bunnik Evelien M. , Pisas Linaida , van Nuenen Ad C. , Schuitemaker Hanneke
Published: June 2008

Most human immunodeficiency virus type 1 (HIV-1)-infected individuals develop an HIV-specific neutralizing antibody (NAb) response that selects for escape variants of the virus. Here, we studied autologous NAb responses in five typical CCR5-using progressors in relation to viral NAb escape and molecular changes in the viral envelope (Env) in the period from seroconversion until after AIDS diagnosis. In sera from three patients, high-titer neutralizing activity was observed against the earliest autologous virus variants, followed by declining humoral immune responses against subsequent viral escape variants. Autologous neutralizing activity was undetectable in sera from two patients. Patients with high-titer neutralizing activity in serum showed the strongest positive selection pressure on Env early in infection. In the initial phase of infection, gp160 length and the number of potential N-linked glycosylation sites (PNGS) increased in viruses from all patients. Over the course of infection, positive selection pressure declined as the NAb response subsided, coinciding with reversions of changes in gp160 length and the number of PNGS. A number of identical amino acid changes were observed over the course of infection in the viral quasispecies of different patients. Our results indicate that although neutralizing autologous humoral immunity may have a limited effect on the disease course, it is an important selection pressure in virus evolution early in infection, while declining HIV-specific humoral immunity in later stages may coincide with reversion of NAb-driven changes in Env.
A Single N-Linked Glycosylation Site in the Japanese Encephalitis Virus prM Protein Is Critical for Cell Type-Specific prM Protein Biogenesis, Virus Particle Release, and Pathogenicity in Mice
Authors: Kim Jeong-Min , Yun Sang-Im , Song Byung-Hak , Hahn Youn-Soo , Lee Chan-Hee , Oh Hyun-Woo , Lee Young-Min
Published: June 2008

The prM protein of Japanese encephalitis virus (JEV) contains a single potential N-linked glycosylation site, N
15
-X
16
-T
17
, which is highly conserved among JEV strains and closely related flaviviruses. To investigate the role of this site in JEV replication and pathogenesis, we manipulated the RNA genome by using infectious JEV cDNA to generate three prM mutants (N15A, T17A, and N15A/T17A) with alanine substiting for N
15
and/or T
17
and one mutant with silent point mutations introduced into the nucleotide sequences corresponding to all three residues in the glycosylation site. An analysis of these mutants in the presence or absence of endoglycosidases confirmed the addition of oligosaccharides to this potential glycosylation site. The loss of prM N glycosylation, without significantly altering the intracellular levels of viral RNA and proteins, led to an ≈20-fold reduction in the production of extracellular virions, which had protein compositions and infectivities nearly identical to those of wild-type virions; this reduction occurred at the stage of virus release, rather than assembly. This release defect was correlated with small-plaque morphology and an N-glycosylation-dependent delay in viral growth. A more conservative mutation, N15Q, had the same effect as N15A. One of the four prM mutants, N15A/T17A, showed an additional defect in virus growth in mosquito C6/36 cells but not human neuroblastoma SH-SY5Y or hamster BHK-21 cells. This cell type dependence was attributed to abnormal N-glycosylation-independent biogenesis of prM. In mice, the elimination of prM N glycosylation resulted in a drastic decrease in virulence after peripheral inoculation. Overall, our findings indicate that this highly conserved N-glycosylation motif in prM is crucial for multiple stages of JEV biology: prM biogenesis, virus release, and pathogenesis.
Effects of Lamin A/C, Lamin B1, and Viral U
S
3 Kinase Activity on Viral Infectivity, Virion Egress, and the Targeting of Herpes Simplex Virus U
L
34-Encoded Protein to the Inner Nuclear Membrane
Authors: Mou Fan , Wills Elizabeth G. , Park Richard , Baines Joel D.
Published: June 2008

Previous results indicated that the U
L
34 protein (pU
L
34) of herpes simplex virus 1 (HSV-1) is targeted to the nuclear membrane and is essential for nuclear egress of nucleocapsids. The normal localization of pU
L
34 and virions requires the U
S
3-encoded kinase that phosphorylates U
L
34 and lamin A/C. Moreover, pU
L
34 was shown to interact with lamin A in vitro. In the present study, glutathione
S
-transferase/pU
L
34 was shown to specifically pull down lamin A and lamin B1 from cellular lysates. To determine the role of these interactions on viral infectivity and pU
L
34 targeting to the inner nuclear membrane (INM), the localization of pU
L
34 was determined in LmnA
−/−
and LmnB1
−/−
mouse embryonic fibroblasts (MEFs) by indirect immunofluorescence and immunogold electron microscopy in the presence or absence of U
S
3 kinase activity. While pU
L
34 INM targeting was not affected by the absence of lamin B1 in MEFs infected with wild-type HSV as viewed by indirect immunofluorescence, it localized in densely staining scalloped-shaped distortions of the nuclear membrane in lamin B1 knockout cells infected with a U
S
3 kinase-dead virus. Lamin B1 knockout cells were relatively less permissive for viral replication than wild-type MEFs, with viral titers decreased at least 10-fold. The absence of lamin A (i) caused clustering of pU
L
34 in the nuclear rim of cells infected with wild-type virus, (ii) produced extensions of the INM bearing pU
L
34 protein in cells infected with a U
S
3 kinase-dead mutant, (iii) precluded accumulation of virions in the perinuclear space of cells infected with this mutant, and (iv) partially restored replication of this virus. The latter observation suggests that lamin A normally impedes viral infectivity and that U
S
3 kinase activity partially alleviates this impediment. On the other hand, lamin B1 is necessary for optimal viral replication, probably through its well-documented effects on many cellular pathways. Finally, neither lamin A nor B1 was absolutely required for targeting pU
L
34 to the INM, suggesting that this targeting is mediated by redundant functions or can be mediated by other proteins.
How Bacteria Consume Their Own Exoskeletons (Turnover and Recycling of Cell Wall Peptidoglycan)
Authors: Park James T. , Uehara Tsuyoshi
Published: June 2008

The phenomenon of peptidoglycan recycling is reviewed. Gram-negative bacteria such asEscherichia colibreak down and reuse over 60% of the peptidoglycan of their side wall each generation. Recycling of newly made peptidoglycan during septum synthesis occurs at an even faster rate. Nine enzymes, one permease, and one periplasmic binding protein inE. colithat appear to have as their sole function the recovery of degradation products from peptidoglycan, thereby making them available for the cell to resynthesize more peptidoglycan or to use as an energy source, have been identified. It is shown that all of the amino acids and amino sugars of peptidoglycan are recycled. The discovery and properties of the individual proteins and the pathways involved are presented. In addition, the possible role of various peptidoglycan degradation products in the induction of β-lactamase is discussed.
Hourly variation in fine particle exposure is associated with transiently increased risk of ST segment depression
Authors: Lanki T , Hoek G , Timonen K L , Peters A , Tiittanen P , Vanninen E , Pekkanen J
Published: June 2008

Objectives:

To evaluate whether hourly changes in fine particle (PM2.5, diameter<2.5 µm) exposure or outdoor particle concentrations are associated with rapid ischaemic responses.

Methods:

41 non-smoking elderly people with coronary heart disease were followed up with biweekly clinic visits in Helsinki, Finland. The occurrence of ST segment depressions >0.1 mV was recorded during submaximal exercise tests. Hourly variations in personal PM2.5exposure and outdoor levels of PM2.5and ultrafine particles (<0.1 µm) were recorded for 24 h before a clinic visit. Associations between particulate air pollution and ST segment depressions were evaluated using logistic regression.

Results:

Both personal and outdoor PM2.5concentrations, but not outdoor ultrafine particle counts, were associated with ST segment depressions. The odds ratio (per 10 µg/m3) for personal PM2.5concentration during the hour preceding a clinic visit was 3.26 (95% CI 1.07 to 9.99) and for 4 h average outdoor PM2.5it was 2.47 (95% CI 1.05 to 5.85).

Conclusions:

Even very short-term elevations in fine particle exposure might increase the risk of myocardial ischaemia. The precise mechanism is still unknown but could involve changes in autonomic nervous control of the heart.
Excess of mesotheliomas after exposure to chrysotile in Balangero, Italy
Authors: Mirabelli D , Calisti R , Barone-Adesi F , Fornero E , Merletti F , Magnani C
Published: June 2008

Background:

Chrysotile from the mine in Balangero, Italy is considered to be free of tremolite. In a cohort study of miners and millers only two pleural cancers were reported, a finding considered to indicate that chrysotile has a low potency for inducing mesothelioma. However, follow-up ended in 1987 and white-collar workers and the employees of subcontractors were not studied.

Methods:

To complete the case ascertainment, the study searched the Registry of Malignant Mesotheliomas of Piedmont for records of cases of pleural mesothelioma among the following: mine employees; employees of subcontractors or of other firms transporting or refining Balangero asbestos, asbestos ore or mine tailings; individuals exposed to air pollution from the mine or living with mine employees; and individuals exposed to mine tailings from Balangero.

Results:

The study identified four new cases of pleural mesothelioma among blue-collar workers in the mine, in addition to the two reported in the cohort study. Thus, six mesotheliomas occurred, compared to the 1.5 expected (p<0.01). The study also identified three mesothelioma cases among white-collar employees at the mine, five in workers in the mine hired by subcontracting firms, and three among workers processing Balangero chrysotile outside the mine. Finally, 10 additional cases due to non-occupational exposure or exposure to re-used mine tailings were identified.

Conclusions:

The cluster of 14 mesothelioma cases among workers who were active in the mine and 13 among other people exposed to Balangero chrysotile provides further evidence that tremolite-free chrysotile is carcinogenic.
Comparison by Plasmid Profiling ofVibrio salmonicidaStrains Isolated from Diseased Fish from Different North European and Canadian Coastal Areas of the Atlantic Ocean
Authors: Sørum Henning , Myhr Egil , Zwicker Betty M. , Lillehaug Atle
Published: June 2008

Strains of Vibrio salmonicida from four different geographical areas, Norway, the Shetland Islands, the Faroe Islands, and eastern Canada, with coastlines bordering the North Atlantic, were subjected to plasmid DNA profiling after morphological, physiological, and serological classification. The strains of V. salmonicida from all these areas had common plasmid profiles, with the three plasmids of 21, 3.4, and 2.8 MDa as the most prevalent. The country of origin did not seem to be related to differences among the strains. Plasmid DNA profiling differentiates V. salmonicida isolates originating from different coastal areas of the North Atlantic into the same set of subgroups.
RAIN Project: Results after 8 Years of Experimentally Reduced Acid Deposition to a Whole Catchment
Authors: Wright Richard F. , Lotse Erik , Semb Arne
Published: June 2008

At Risdalsheia (southern Norway), an ongoing catchment-scale acid-exclusion experiment has been conducted since 1984 as part of the RAIN project (Reversing Acidification In Norway). Acid precipitation is collected on a 1200-m2transparent roof, treated by ion exchange, sea salts readded, and reapplied as clean rain beneath the roof Up to 1990 annual surveys of soil chemistry have revealed no significant trends. The chemical composition of runoff has changed: sulfate decreased from about 111 μeq/L in 1984 to 38 μeq/L in 1992 and nitrate from about 33 to 5 μeq/L. Base cations decreased and alkalinity increased over the 8-yr period from −88 to −29 μeq/L to compensate for this change in strong acid anions. Much of the alkalinity change is due to the increased role of organic anions. The results fit an empirical nomograph relating alkalinity, base cations, and strong acid anions and a new empirical nomograph relating alkalinity, H+, and total organic carbon. The acid-exclusion experiment provides the first catchment-scale evidence for the reversibility of nitrogen saturation; RAIN results corroborate field observations of changes in surface water chemistry in response to reduced acid deposition as well as process-oriented, conceptual acidification models.
Predation by River Otters (Lutra canadensis) on Juvenile Coho Salmon (Oncorhynchus kisutch) and Dolly Varden (Salvelinus malma) in Southeast Alaska
Authors: Dolloff C. Andrew
Published: June 2008

The effect of predation by river otters (Lutra canadensis) on juvenile coho salmon (Oncorhynchus kisutch) and Dolly Varden (Salvelinus malma) in a Southeast Alaska watershed was inferred by examining the number and size distribution of sagittal otoliths that were found in otter scats. Individual scats contained up to 408 otoliths, indicating that at least 200 fish had been eaten between defecations. Otoliths from juvenile salmonids outnumbered those from coastrange sculpins (Cottus aleuticus) by about six to one. Based on examination of over 8000 otoliths found in otter scats, at least 3300 juvenile salmonids were eaten by two river otters and their two young in the Kadashan River system during a 6-wk period in late spring 1985.
Protozoan Grazing and the Size–Activity Structure of Limnetic Bacterial Communities
Authors: Bird David F. , Kalff Jacob
Published: June 2008

We measured bacterial growth rates by labelled thymidine incorporation, grazing loss rates with fluorescent latex particles, and bacterial cell size and abundance within narrow size-fractions of freshwater bacterioplankton. Contrary to the predictions of standard allometric relationships, the smallest bacteria showed the lowest incorporation rate per cell and per unit DNA content. Cells trapped by 1- and 5-μm filters grew the fastest and were responsible for 86% of detected thymidine biosynthesis. Grazing studies in six lakes showed that grazing pressure from flagellated protozoans and mixotrophic algae on large bacterial cells was probably 2–40 times more intense than that on the smallest cells. We suggest that reduced grazing pressure on the smallest bacteria allows them to dominate numerically, despite their slower growth.
Lipid Dynamics in Relation to the Annual Reproductive Cycle in Yellowtail Rockfish (Sebastes flavidus)
Authors: MacFarlane R. Bruce , Norton Elizabeth C. , Bowers Michael J.
Published: June 2008

In yellowtail rockfish (Sebastes fiavidus), lipids that accumulated in mesenteries and liver during the summer and early fall upwelling were subsequently translocated to developing ovaries during late fall and winter. Tissue and serum lipids were assessed by stage of ovary maturation from fish collected monthly over six annual reproductive cycles (1985–91) from Cordell Bank, a seamount off central California. Lipids were primarily transported to ovaries prior to fertilization. Energetic lipids (triglycerides, nonesterified fatty acids) were maximal in serum during yolk accumulation stages and declined significantly during embryonic stages. Between fertilization and parturition, lipid and protein content of ovaries declined by about 21%, a value approaching the minimum for lecithotrophy (i.e. ovoviviparity). During gestation, however, serum phospholipids and calcium (vitellogenin surrogate) were significantly elevated relative to male levels, suggesting matrotrophic contributions. A reproductive mode that is primarily lecithotrophic but supplemented by maternal inputs during embryogenesis would be beneficial to viviparous fishes of the California coast. This strategy may optimize reproduction by coupling the disparate times of food abundance and gestation, yet allow for provision of nutrients late in the reproductive cycle should they be available.
Assessing the Interdependence of Assemblages from Rainy Lake Fisheries Data
Authors: Cohen Yosef , Radomski Paul , Moen Ron
Published: June 2008

We applied ad hoc methods to quantify differences among fish communities in four different locations in Rainy Lake using data from index netting from long-term studies. Our analysis addressed problems of inconsistencies in data collection. We established the amount of differences and similarities among the communities by analyzing species diversity over time, utilizing matrices of partial correlations and discriminant function analysis. We also identified role reversal, i.e. synchronization in fluctuations of relative catch-per-unit-effort (CUE) between pairs of species in these communities. In the less disturbed communities, walleye (Stizostedion vitreum) contributed most to the synchronization in the fluctuations of the yearly relative CUE among six common species. In the more disturbed locations, this contribution was primarily due to yellow perch (Perca flavescens) and sauger (Stizostedion canadense). The disturbed community in one location (the North Arm) exhibited marked decrease in species diversity. Recent restrictions on the fisheries in the North Arm resulted in an increase in species diversity. Fish communities, particularly in large lakes, may differ in the detail of species interactions and population fluctuations among locations within the lake. These differences must be taken into account in analysis and management of fisheries.
Isolation and characterization of ZH14 with antiviral activity againstTobacco mosaic virus
Authors: Zhou Wen-Wen , Zhang Li-Xiang , Zhang Bin , Wang Fei , Liang Zhi-Hong , Niu Tian-Gui
Published: June 2008

A large number of bacteria were isolated from plant samples and screened for antiviral activity against the Tobacco mosaic virus (TMV). The bacterium ZH14, which was isolated from Chinese Anxi oolong tea, secreted the antiviral substances, having 94.2% virus inhibition when the bacterial culture filtrate and TMV extract were mixed at a ratio of 1:1. The ZH14 strain is a gram-positive, spore-forming rod and has the ability to degrade ribonucleic acid. Based on its effectiveness on virus inhibition, ZH14 was selected for characterization and was identified as a strain of the Bacillus cereus group based on phenotypic tests and comparative analysis of its 16S rDNA sequence. At the same time, we determined the antiviral product of ZH14 as an extracellular protein with high molecular mass, having an optimum temperature of 15–60 °C and an optimum pH of 6–10. Hence, the ZH14 strain and its culture filtrate have potential application in controlling plant diseases caused by TMV.
In vitro evaluation of the effect of nicotine, cotinine, and caffeine on oral microorganisms
Authors: Cogo Karina , Montan Michelle Franz , Bergamaschi Cristiane de Cássia , D. Andrade Eduardo , Rosalen Pedro Luiz , Groppo Francisco Carlos
Published: June 2008

The aim of this in vitro study was to evaluate the effects of nicotine, cotinine, and caffeine on the viability of some oral bacterial species. It also evaluated the ability of these bacteria to metabolize those substances. Single-species biofilms of Streptococcus gordonii , Porphyromonas gingivalis , or Fusobacterium nucleatum and dual-species biofilms of S. gordonii – F. nucleatum and F. nucleatum – P. gingivalis were grown on hydroxyapatite discs. Seven species were studied as planktonic cells, including Streptococcus oralis , Streptococcus mitis , Propionibacterium acnes , Actinomyces naeslundii , and the species mentioned above. The viability of planktonic cells and biofilms was analyzed by susceptibility tests and time-kill assays, respectively, against different concentrations of nicotine, cotinine, and caffeine. High-performance liquid chromatography was performed to quantify nicotine, cotinine, and caffeine concentrations in the culture media after the assays. Susceptibility tests and viability assays showed that nicotine, cotinine, and caffeine cannot reduce or stimulate bacterial growth. High-performance liquid chromatography results showed that nicotine, cotinine, and caffeine concentrations were not altered after bacteria exposure. These findings indicate that nicotine, cotinine, and caffeine, in the concentrations used, cannot affect significantly the growth of these oral bacterial strains. Moreover, these species do not seem to metabolize these substances.
A PREY–PREDATOR MODEL WITH MICROPARASITE INFECTION IN THE PREDATOR
Authors: MAITI A. , BERA S. P. , SAMANTA G. P.
Published: June 2008

This paper aims to study the dynamical behaviors of a predator–prey system where the predator is affected by a microparasite infection. The effect of discrete time-delay is investigated. It has been shown that the time-delay can induce instability and oscillations via Hopf bifurcation. Also delay of suitable range may keep the populations at a desired level. Computer simulations are carried out to illustrate our analytical findings. The biological implications of our analytical and numerical findings are discussed critically.
COMPARATIVE ANALYSIS OF DISEASE-ASSOCIATED MUTATIONS IN THE CODING REGIONS OF ALTERNATIVELY AND CONSTITUTIVELY SPLICED HUMAN GENES
Authors: HUANG QIANLI , LI YONG , LI-LING JESSE , HUANG HUIFANG , CHEN XUEPING , MA FEI
Published: June 2008

To better understand the evolutionary and molecular mechanisms of alternative splicing causing human diseases, we have systematically compared the pattern, the distribution and the density of disease-associated mutations as well as the influence of codon usage bias on the single mutation between alternatively and constitutively spliced genes through analysis of the large datasets from human disease genes. The results indicated that:

1. The most common pattern of single mutation in alternatively and constitutively spliced genes are, respectively, C/T (25.17%), (22.81%) and G/A (21.54%), (22.73%), suggesting that the two types of disease genes are prone to C → T and G → A mutations.

2. There is an overall preponderance for transitions over transversions in alternatively (62.88% versus 37.12%) and constitutively (64.41% versus 35.59%) spliced disease genes.

3. For the second base of codons, there exist significant differences in transitions and transversions between the two types of genes.

4. Our data indicated that the single mutation tends to occur preferentially when the upstream neighboring-nucleotide is C or G in human disease genes.

5. Codon usage bias and synonymous codon usage have great influence on the single mutation in both alternatively and constitutively spliced genes. The GC content and gene length also have very evident influence on such mutations.

Our results seem to imply that disease-associated mutations within the coding regions of alternatively spliced human disease genes have different mechanisms from constitutively spliced genes. Such findings may facilitate understanding the molecular mechanism of alternative splicing causing human diseases, and the development of gene therapies for such diseases.
Chemical and Nd isotope constraints on granitoid sources involved in the Caledonian Orogeny in Scotland
Authors: STEINHOEFEL GRIT , HEGNER ERNST , OLIVER GRAHAME J.H.
Published: June 2008

Major- and trace-element data and Nd isotope compositions for granitoid samples from the Grampian Highlands in Scotland show a systematic evolution in the composition of their sources in the course of the Caledonian Orogeny. Granitoids of 511–451 Ma, related to the collision of the Midland Valley island arc with the Grampian terrane, show S-type affinity and fractionated REE patterns with minor Eu anomalies and low initial ϵ
Nd
values of −14.1 to −11.2 suggesting melting of predominantly Dalradian metasediments. Subsequently formed granitoids of 425–406 Ma derived from an assumed Andean plate margin comprise a wide spectrum of rock types including I-type granite–granodiorite, and S-type granitoids, monzonites and alkali granites. The trace-element patterns of these rocks and the range of initial ϵ
Nd
values of −2.1 to −6.9 are consistent with melting of variably rejuvenated crust as found in continental margin settings. We conclude that the Grampian Highlands were affected by two major crust-modifying events during the Caledonian Orogeny: predominantly recycling of older crust during docking of the Midland Valley arc and addition of juvenile, mantle-derived material to the crust during the convergence of Avalonia with Laurentia.
Central G-alpha subunit protein-mediated control of cardiovascular function, urine output, and vasopressin secretion in conscious Sprague-Dawley rats
Authors: Wainford Richard D. , Kurtz Kristine , Kapusta Daniel R.
Published: June 2008

The role(s) of central Gα-proteins in the regulation of cardiovascular and renal function is unknown. We examined how inhibition/downregulation of central Gαi/Gαo, Gαz or Gαq proteins altered the characteristic cardiovascular (depressor), renal excretory (diuretic), and plasma AVP (inhibitory) responses to intracerebroventricular injection of nociceptin/orphanin FQ (N/OFQ) in rats. Before investigation, rats were pretreated intracerebroventricularly with saline vehicle (5 μl, 48 h, n = 6), pertussis toxin (PTX; 48-h, 1 μg, n = 6), or Gαz, Gαq, or scrambled oligodeoxynucleotide (ODN) (25 μg, 24 h, n = 6 per group). On the study day, intracerebroventricular N/OFQ (5.5 nmol) or vehicle (5 μl) was injected into pretreated conscious rats. Mean arterial pressure (MAP) and heart rate (HR) were recorded, and urine was collected for 90 min. In vehicle or scrambled ODN groups, intracerebroventricular N/OFQ decreased MAP and HR and produced water diuresis (sensitive to UFP-101, N/OFQ receptor antagonist). The hypotension and bradycardia, but not diuresis, to N/OFQ were abolished in PTX-pretreated rats. In contrast, intracerebroventricular ODN pretreatment markedly blunted (Gαz) or augmented (Gαq) the diuresis to intracerebroventricular N/OFQ. In separate studies, the action of central N/OFQ to decrease plasma AVP levels in naïve water-restricted rats was differentially altered by intracerebroventricular Gαz ODN (blunted) and Gαq ODN (augmented) pretreatment. These studies demonstrate central Gαi/Gαo activity mediates intracerebroventricular N/OFQ's cardiovascular depressor function. Alternatively, central Gαz (inhibitory) and Gαq (stimulatory) activity differentially modulates AVP release to control the pattern of diuresis to intracerebroventricular N/OFQ. These findings highlight the novel selective central Gα-subunit protein-mediated control of cardiovascular vs. renal excretory function.
Dietary carbohydrates induce changes in glucosensing capacity and food intake of rainbow trout
Authors: Polakof Sergio , Míguez Jesús M. , Soengas José L.
Published: June 2008

We hypothesize that variations in dietary carbohydrate levels produce changes in glucosensor parameters in previously characterized glucosensing areas (hypothalamus and hindbrain) related with the regulation of food intake of a carnivorous fish species like rainbow trout. Therefore, we fed trout with standard, carbohydrate-free (CF) or high-carbohydrate (HC) diets for 10 days to assess changes in glucosensing system and food intake. Fish fed CF diet displayed hypoglycemia and increased food intake. Fish fed a HC diet displayed hyperglycemia and decreased food intake. Changes in food intake due to dietary carbohydrates were accompanied in hypothalamus and hindbrain of fish fed with HC diet by changes in parameters involved in glucosensing, such as increased glucose, glucose 6-phosphate, and glycogen levels and increased glucokinase (GK), glycogen synthase, and pyruvate kinase activities as well as increased GK and GLUT2 expression. All those results address for the first time in fish, despite the relative intolerance to glucose of carnivorous species, that dietary carbohydrates are important regulators of the glucosensing system in carnivorous fish, suggesting that the information generated by this system can be associated with the changes observed in food intake.
Activation of mesolimbic dopamine neurons during novel and daily limited access to palatable food is blocked by the opioid antagonist LY255582
Authors: Sahr Allison E. , Sindelar Dana K. , Alexander-Chacko Jesline T. , Eastwood Brian J. , Mitch Charles H. , Statnick Michael A.
Published: June 2008

An analog of the trans-3,4-dimethyl-4-(3-hydroxyphenyl)piperidine series (LY255582) exhibits high in vitro binding affinity and antagonist potency for the μ-, δ-, and κ-opioid receptors. In vivo, LY255582 exhibits potent effects in reducing food intake and body weight in several rodent models of obesity. In the present study, we evaluated the effects of LY255582 to prevent the consumption of a highly palatable (HP) diet (a high-fat/high-carbohydrate diet) both when the food was novel and following daily limited access to the HP diet. Additionally, we examined the effects of consumption of the HP diet and of LY255582 treatment on mesolimbic dopamine (DA) signaling by in vivo microdialysis. Consumption of the HP diet increased extracellular DA levels within the nucleus accumbens (NAc) shell. Increased DA in the NAc shell was not related to the quantity of the HP diet consumed, and the DA response did not habituate following daily scheduled access to the HP diet. Interestingly, treatment with LY255582 inhibited consumption of the HP diet and the HP diet-associated increase in NAc shell DA levels. Moreover, the increased HP diet consumption observed following daily limited access to the HP diet was completely prevented by LY255582 treatment. LY255582 may be a useful tool in understanding the neural mechanisms involved in the reinforcement mechanisms regulating food intake.
ADP-ribosyl cyclase and ryanodine receptors mediate endothelin ETAand ETBreceptor-induced renal vasoconstriction in vivo
Authors: Thai Tiffany L. , Arendshorst William J.
Published: June 2008

ADP-ribosyl cyclase (ADPR cyclase) and ryanodine receptors (RyR) participate in calcium transduction in isolated afferent arterioles. We hypothesized that this signaling pathway is activated by ETAand ETBreceptors in the renal vasculature to mediate vasoconstriction in vivo. To test this, we measured acute renal blood flow (RBF) responses to ET-1 in anesthetized rats and mice in the presence and absence of functional ADPR cyclase and/or RyR. Inhibitors of ADPR cyclase (nicotinamide) or RyR (ruthenium red) reduced RBF responses to ET-1 by 44% ( P < 0.04 for both) in Sprague-Dawley rats. Mice lacking the predominant form of ADPR cyclase (CD38−/−) had RBF responses to ET-1 that were 47% weaker than those seen in wild-type mice ( P = 0.01). Selective ETAreceptor stimulation (ET-1+BQ788) produced decreases in RBF that were attenuated by 43 and 56% by nicotinamide or ruthenium red, respectively ( P < 0.02 for both). ADPR cyclase or RyR inhibition also reduced vasoconstrictor effects of the ETBreceptor agonist sarafotoxin 6c (S6c; 77 and 54%, respectively, P < 0.02 for both). ETBreceptor stimulation by ET-1 + the ETAreceptor antagonist BQ123 elicited responses that were attenuated by 59 and 60% by nicotinamide and ruthenium red, respectively ( P < 0.01 for both). Nicotinamide attenuated RBF responses to S6c by 54% during inhibition of nitric oxide synthesis ( P = 0.001). We conclude that in the renal microcirculation in vivo 1) ET-1-induced vasoconstriction is mediated by ADPR cyclase and RyR; 2) both ETAand ETBreceptors activate this pathway; and 3) ADPR cyclase participates in ETBreceptor signaling independently of NO.
FR167653 inhibits fibronectin expression and apoptosis in diabetic glomeruli and in high-glucose-stimulated mesangial cells
Authors: Jung Dong-Sub , Li Jin Ji , Kwak Seung-Jae , Lee Sun Ha , Park Jehyun , Song Young Soo , Yoo Tae-Hyun , Han Seung Hyeok , Lee Jung Eun , Kim Dong Ki , Moon Sung Jin , Kim Yu Seun , Han Dae Suk , Kang Shin-Wook
Published: June 2008

Previous in vitro studies suggest that the p38 MAPK pathway may be involved in the pathogenesis of diabetic nephropathy, but the consequences of the inhibition of the p38 MAPK pathway have not been well elucidated in diabetic (DM) glomeruli. This study was undertaken to investigate the effect of p38 MAPK inhibitor, FR167653, on fibronectin expression and apoptosis in DM glomeruli and in high-glucose-stimulated mesangial cells (MC). In vivo, 32 Sprague-Dawley rats were injected with diluent (control, N = 16) or streptozotocin intraperitoneally (DM, N = 16). Eight rats from each group were treated with FR167653 for 3 mo. In vitro, rat MC were exposed to medium containing 5.6 mM glucose or 30 mM glucose [high glucose (HG)] with or without 10−6M FR167653 for 24 h. Fibronectin mRNA and protein expression were determined by real-time PCR and Western blot, respectively. Western blot for apoptosis-related molecules, terminal deoxynucleotidyl transferase dUTP-mediated nick-end labeling assay, and Hoechst 33342 staining were performed to determine apoptosis. FR167653 ameliorated the increases in fibronectin-to-GAPDH mRNA ratio and protein expression in DM glomeruli by 89 and 79% and in HG-stimulated MC by 70 and 91%, respectively ( P < 0.05). Under diabetic conditions, Bcl-2 protein expression was decreased, whereas cleaved caspase-3 protein expression was increased ( P < 0.05), and these changes were inhibited by FR167653 treatment. Apoptotic cells were also significantly increased in DM glomeruli and in HG-stimulated MC ( P < 0.05), and FR167653 ameliorated these increases in apoptotic cells, both in vivo and in vitro. In conclusion, these findings suggest that the inhibition of the p38 MAPK pathway has a beneficial effect on the development of diabetic nephropathy by inhibiting the increase in fibronectin expression and apoptosis.
Time to task failure and muscle activation vary with load type for a submaximal fatiguing contraction with the lower leg
Authors: Hunter Sandra K. , Yoon Tejin , Farinella Joseph , Griffith Erin E. , Ng Alexander V.
Published: June 2008

The purpose was to compare the time to failure and muscle activation patterns for a sustained isometric submaximal contraction with the dorsiflexor muscles when the foot was restrained to a force transducer (force task) compared with supporting an equivalent inertial load and unrestrained (position task). Fifteen men and women (mean ± SD; 21.1 ± 1.4 yr) performed the force and position tasks at 20% maximal voluntary contraction force until task failure. Maximal voluntary contraction force performed before the force and position tasks was similar (333 ± 71 vs. 334 ± 65 N), but the time to task failure was briefer for the position task (10.0 ± 6.2 vs. 21.3 ± 17.8 min, P < 0.05). The rate of increase in agonist root-mean-square electromyogram (EMG), EMG bursting activity, rating of perceived exertion, fluctuations in motor output, mean arterial pressure, and heart rate during the fatiguing contraction was greater for the position task. EMG activity of the vastus lateralis (lower leg stabilizer) and medial gastrocnemius (antagonist) increased more rapidly during the position task, but coactivation ratios (agonist vs. antagonist) were similar during the two tasks. Thus the difference in time to failure for the two tasks with the dorsiflexor muscles involved a greater level of neural activity and rate of motor unit recruitment during the position task, but did not involve a difference in coactivation. These findings have implications for rehabilitation and ergonomics in minimizing fatigue during prolonged activation of the dorsiflexor muscles.
A Hebbian Learning Rule Mediates Asymmetric Plasticity in Aligning Sensory Representations
Authors: Witten Ilana B. , Knudsen Eric I. , Sompolinsky Haim
Published: June 2008

In the brain, mutual spatial alignment across different sensory representations can be shaped and maintained through plasticity. Here, we use a Hebbian model to account for the synaptic plasticity that results from a displacement of the space representation for one input channel relative to that of another, when the synapses from both channels are equally plastic. Surprisingly, although the synaptic weights for the two channels obeyed the same Hebbian learning rule, the amount of plasticity exhibited by the respective channels was highly asymmetric and depended on the relative strength and width of the receptive fields (RFs): the channel with the weaker or broader RFs always exhibited most or all of the plasticity. A fundamental difference between our Hebbian model and most previous models is that in our model synaptic weights were normalized separately for each input channel, ensuring that the circuit would respond to both sensory inputs. The model produced three distinct regimes of plasticity dynamics (winner-take-all, mixed-shift, and no-shift), with the transition between the regimes depending on the size of the spatial displacement and the degree of correlation between the sensory channels. In agreement with experimental observations, plasticity was enhanced by the accumulation of incremental adaptive adjustments to a sequence of small displacements. These same principles would apply not only to the maintenance of spatial registry across input channels, but also to the experience-dependent emergence of aligned representations in developing circuits.
Human rhomboid family-1 gene silencing causes apoptosis or autophagy to epithelial cancer cells and inhibits xenograft tumor growth
Authors: Yan Zhenwen , Zou Huafei , Tian Fang , Grandis Jennifer R. , Mixson A. James , Lu Patrick Y. , Li Lu-Yuan
Published: June 2008

The rhomboid family of genes carry out a wide range of important functions in a variety of organisms. Little is known, however, about the function of the human rhomboid family-1 gene (RHBDF1). We show here that RHBDF1 function is essential to epithelial cancer cell growth. RHBDF1 mRNA level is significantly elevated in clinical specimens of invasive ductal carcinoma of the breast, and the protein is readily detectable in human breast cancer or head and neck cancer cell lines. Silencing the RHBDF1 gene with short interfering RNA (siRNA) results in apoptosis in breast cancer MDA-MB-435 cells and autophagy in head and neck squamous cell cancer 1483 cells. The treatment also leads to significant down-modulation of activated AKT and extracellular signal-regulated kinase in the cells, suggesting that critically diminished strength of these growth signals may be the key attributes of the induction of cell death. Furthermore, silencing the RHBDF1 gene in MDA-MB-435 or 1483 xenograft tumors on athymic nude mice by using i.v. administered histidine-lysine polymer nanoparticle-encapsulated siRNA results in marked inhibition of tumor growth. Our findings indicate that RHBDF1 has a pivotal role in sustaining growth signals in epithelial cancer cells and thus may serve as a therapeutic target for treating epithelial cancers. [Mol Cancer Ther 2008;7(6):1355–64]
Generation of adenovirus-mediated anti-CD20 antibody and its effect on B-cell deletion in mice and nonhuman primate cynomolgus monkey
Authors: Chen Jie , Su Changqing , Lu Qiujun , Shi Wenfang , Zhang Qi , Wang Xinghua , Long Ju , Yang Qin , Li Linfang , Jia Xiaoyuan , Wang Jianming , Da Wanming , Liu Xinyuan , Wu Mengchao , Qian Qijun
Published: June 2008

Therapeutic monoclonal anti-CD20 antibody (Rituxan) is increasingly applied to treat B-cell-related hematologic malignancies and autoimmune disorders with great clinical success, whereas its widespread application is limited by antibody manufacturing capability. Here, we explored a quick and economical adenovirus-mediated anti-CD20 antibody generating system to directly produce anti-CD20 antibody in vivo. We generated a recombinant adenovirus encoding the anti-CD20 antibody gene and found that infection of cells with this recombinant adenovirus led to the generation of anti-CD20 antibody in cells with a similar CD20 binding affinity and specificity as commercial product Rituxan. After one single administration of the anti-CD20-expressing adenoviruses through tail vein at a dose of 1 × 109 plaque-forming units/mouse in nude mice, anti-CD20 antibody in the serum was detectable at day 3, reached to the peak value of 246.34 μg/mL at day 14, and maintained a high serum concentration of >40 μg/mL for 56 days. Furthermore, the in vivo generation of anti-CD20 antibody led a complete elimination of preestablished B-cell lymphoma Raji cells in nude mice, and a single administration of the anti-CD20-expressing adenovirus at a dose of 2.0 × 109 plaque-forming units/kg in cynomolgus monkey led a continuous B-cell deletion in circulation blood and bone marrow. These observations thus suggest that adenovirus-mediated in vivo generation of anti-CD20 antibody may serve as a new strategy to combat B-cell-related hematologic disorders. [Mol Cancer Ther 2008;7(6):1562–8]
Malondialdehyde and Nitric Oxide Levels in Erythrocytes from Patients with Systemic Sclerosis
Authors: Devrim Erdinç , Erten Şükran , Ergüder İmge B. , Namuslu Mehmet , Turgay Murat , Durak İlker
Published: June 2008

Objective: To investigate malondialdehyde (MDA) and nitric oxide (NO) levels in the erythrocytes from patients with systemic sclerosis (SSc). Subjects and Methods: Twenty-nine patients diagnosed as having SSc and 16 volunteer healthy subjects (as control group) participated in the study. Fasting blood samples were obtained from the patients and healthy subjects in anticoagulated tubes (with EDTA), and the erythrocytes were separated. The MDA and NO levels were measured in the erythrocyte sediments by the spectrophotometric method. Results: The levels of MDA and NO were elevated in the erythrocyte sediments of the patients as compared to those of the control group (1.037 ± 0.125 vs. 0.951 ± 0.114 µmol/g Hb, respectively, p = 0.047 for MDA, and 0.340 ± 0.071 vs. 0.209 ± 0.074 mmol/g Hb, respectively, p < 0.001 for NO). A weak positive correlation was also observed between MDA and NO levels (r = 0.30, p = 0.15 in the patient group, and r = 0.27, p = 0.49 in the control group). Conclusions: Our results show higher levels of MDA and NO in the erythrocytes of patients with SSc than normal subjects.
Protective Effect of Different Tetrafluorides on Erosion of Pellicle-Free and Pellicle-Covered Enamel and Dentine
Authors: Wiegand A. , Meier W. , Sutter E. , Magalhães A.C. , Becker K. , Roos M. , Attin T.
Published: June 2008

The aim was to analyze the protective effects of titanium, zirconium and hafnium tetrafluorides on erosion of pellicle-free and pellicle-covered enamel and dentine in vitro. Eight groups of 20 specimens each of bovine enamel and bovine dentine were prepared. Half the specimens in each group were immersed in human saliva for 2 h for pellicle formation. Specimens were then left untreated (controls) or were treated for 120 s with TiF4, ZrF4 or HfF4 solutions (0.4 or 1%) or 1.25% AmF/NaF gel. All specimens were eroded by exposure to hydrochloric acid, pH 2.6, for 25 min. Cumulative calcium release into the acid was monitored in consecutive 30-second intervals for 5 min, then at 2-min intervals up to a total erosion time of 25 min using the Arsenazo III procedure. Data were analyzed by ANOVA. 1% TiF4 solution offered the best protective effect, especially in dentine (reduction of calcium loss about 50% at 25 min). 1% ZrF4, 1% HfF4 and 0.4% TiF4 also reduced calcium loss, but to a lesser extent. Long-term effects were limited to dentine, while reduction of enamel erosion (about 25%) was restricted to 1-min erosion. The fluoride gel had a protective effect only in dentine. The efficacy of the tetrafluorides was influenced by the presence of the pellicle layer, in that the protection against dentine erosion by TiF4 and ZrF4 was greater on pellicle-covered specimens. Tetrafluoride solutions, especially 1% TiF4, could decrease dental erosion, but were more effective on dentine than on enamel.
Cigarette Smoking and Dental Caries among Professional Truck Drivers in Mexico
Authors: Aguilar-Zinser V. , Irigoyen M.E. , Rivera G. , Maupomé G. , Sánchez-Pérez L. , Velázquez C.
Published: June 2008

Background: Professional truck drivers are at high risk of chronic diseases. Further examination of tobacco use and its impact on oral health is warranted – both in terms of the direct association between tobacco use and poor oral health, and in terms of tobacco use being an indicator of poor health behaviors. Objective: To estimate the possible association between smoking and dental caries experience in a population with high tobacco use. Methods: Drivers’ licenses are periodically re-issued by the Mexican government and as part of the licensing process a physical exam takes place. We administered a free, standardized questionnaire together with an oral examination (WHO criteria) included in the physical exam, targeting a random sample of applicants in Mexico City. Results: A total of 824 dentate males (mean age 35.5 ± 10 years) took part in the study, of whom 49.2% were current smokers and 23.2% were former smokers. Caries experience was mean DMFT 8.95 (± 6.05). Only 18.0% of participants had ‘excellent’ or ‘good’ oral hygiene. The prevalence of ‘large’ cavities increased as the number of cigarettes/day increased from 14.6% (1–3 cigarettes/day) to 33.3% (≧10 cigarettes/day). Using multiple linear regressions, we found that older age, poorer oral hygiene, higher education, and greater tobacco exposure were significantly associated with higher caries experience (DMFT). An interaction was observed with oral hygiene and tobacco: drivers that smoked and had ‘poor’ oral hygiene showed the highest number of large cavities and missing teeth. Health promotion interventions are needed in this at-risk population group.