bluuebunny/crossref_metadata_2025_split huggingface dataset:
From Resistance to Stimulation: the Evolution of a Virus in the Presence of a Dominant Lethal Inhibitory Scaffolding Protein
Authors: Cherwa James E. , Fane Bentley A. 
Published: April 2011

ABSTRACT

By acquiring resistance to an inhibitor, viruses can become dependent on that inhibitor for optimal fitness. However, inhibitors rarely, if ever, stimulate resistant strain fitness to values that equal or exceed the uninhibited wild-type level. This would require an adaptive mechanism that converts the inhibitor into a beneficial replication factor. Using a plasmid-encoded inhibitory external scaffolding protein that blocks φX174 assembly, we previously demonstrated that such mechanisms are possible. The resistant strain, referred to as the evolved strain, contains four mutations contributing to the resistance phenotype. Three mutations confer substitutions in the coat protein, whereas the fourth mutation alters the virus-encoded external scaffolding protein. To determine whether stimulation by the inhibitory protein coevolved with resistance or whether it was acquired after resistance was firmly established, the strain temporally preceding the previously characterized mutant, referred to as the intermediary strain, was isolated and characterized. The results of the analysis indicated that the mutation in the virus-encoded external scaffolding protein was primarily responsible for stimulating strain fitness. When the mutation was placed in a wild-type background, it did not confer resistance. The mutation was also placed in
cis
with the plasmid-encoded dominant lethal mutation. In this configuration, the stimulating mutation exhibited no activity, regardless of the genotype (wild type, evolved, or intermediary) of the infecting virus. Thus, along with the coat protein mutations, stimulation required two external scaffolding protein genes: the once inhibitory gene and the mutant gene acquired during evolution.
Partial Functional Complementation between Human and Mouse Cytomegalovirus Chemokine Receptor Homologues
Authors: Farrell Helen E. , Abraham Alexander M. , Cardin Rhonda D. , Sparre-Ulrich Alexander H. , Rosenkilde Mette M. , Spiess Katja , Jensen Tine H. , Kledal Thomas N. , Davis-Poynter Nicholas 
Published: April 2011

ABSTRACT
The human cytomegalovirus (CMV) proteins US28 and UL33 are homologous to chemokine receptors (CKRs). Knockout of the mouse CMV M33 protein (UL33 homologue) results in substantial attenuation of salivary gland infection/replication and reduced efficiency of reactivation from tissue explants. M33-mediated G protein-coupled signaling is critical for the salivary gland phenotype. In this report, we demonstrate that US28 and (to a lesser degree) UL33 restore reactivation from tissue explants and partially restore replication in salivary glands (compared to a signaling-deficient M33 mutant). These studies provide a novel small animal model for evaluation of therapies targeting the human CMV CKRs.
The Replisome Pausing Factor Timeless Is Required for Episomal Maintenance of Latent Epstein-Barr Virus
Authors: Dheekollu Jayaraju , Lieberman Paul M. 
Published: April 2011

ABSTRACT
The Epstein-Barr virus (EBV) genome is maintained as an extrachromosomal episome during latent infection of B lymphocytes. Episomal maintenance is conferred by the interaction of the EBV-encoded nuclear antigen 1 (EBNA1) with a tandem array of high-affinity binding sites, referred to as the family of repeats (FR), located within the viral origin of plasmid replication (OriP). How this nucleoprotein array confers episomal maintenance is not completely understood. Previous studies have shown that DNA replication forks pause and terminate with high frequency at OriP. We now show that cellular DNA replication fork pausing and protection factors Timeless (Tim) and Tipin (Timeless-interacting protein) accumulate at OriP during S phase of the cell cycle. Depletion of Tim inhibits OriP-dependent DNA replication and causes a complete loss of the closed-circular form of EBV episomes in latently infected B lymphocytes. Tim depletion also led to the accumulation of double-strand breaks at the OriP region. These findings demonstrate that Tim is essential for sustaining the episomal forms of EBV DNA in latently infected cells and suggest that DNA replication fork protection is integrally linked to the mechanism of plasmid maintenance.
Analysis of Interferon Signaling by Infectious Hepatitis C Virus Clones with Substitutions of Core Amino Acids 70 and 91
Authors: Funaoka Yusuke , Sakamoto Naoya , Suda Goki , Itsui Yasuhiro , Nakagawa Mina , Kakinuma Sei , Watanabe Takako , Mishima Kako , Ueyama Mayumi , Onozuka Izumi , Nitta Sayuri , Kitazume Akiko , Kiyohashi Kei , Murakawa Miyako , Azuma Seishin , Tsuchiya Kiichiro , Watanabe Mamoru 
Published: April 2011

ABSTRACTSubstitution of amino acids 70 and 91 in the hepatitis C virus (HCV) core region is a significant predictor of poor responses to peginterferon-plus-ribavirin therapy, while their molecular mechanisms remain unclear. Here we investigated these differences in the response to alpha interferon (IFN) by using HCV cell culture with R70Q, R70H, and L91M substitutions. IFN treatment of cells transfected or infected with the wild type or the mutant HCV clones showed that the R70Q, R70H, and L91M core mutants were significantly more resistant than the wild type. Among HCV-transfected cells, intracellular HCV RNA levels were significantly higher for the core mutants than for the wild type, while HCV RNA in culture supernatant was significantly lower for these mutants than for the wild type. IFN-induced phosphorylation of STAT1 and STAT2 and expression of the interferon-inducible genes were significantly lower for the core mutants than for the wild type, suggesting cellular unresponsiveness to IFN. The expression level of an interferon signal attenuator, SOCS3, was significantly higher for the R70Q, R70H, and L91M mutants than for the wild type. Interleukin 6 (IL-6), which upregulates SOCS3, was significantly higher for the R70Q, R70H, and L91M mutants than for the wild type, suggesting interferon resistance, possibly through IL-6-induced, SOCS3-mediated suppression of interferon signaling. Expression levels of endoplasmic reticulum (ER) stress proteins were significantly higher in cells transfected with a core mutant than in those transfected with the wild type. In conclusion, HCV R70 and L91 core mutants were resistant to interferonin vitro, and the resistance may be induced by IL-6-induced upregulation of SOCS3. Those mechanisms may explain clinical interferon resistance of HCV core mutants.
The Copenhagen Hip and Groin Outcome Score (HAGOS): development and validation according to the COSMIN checklist
Authors: Thorborg K , Hölmich P , Christensen R , Petersen J , Roos E M 
Published: April 2011

BackgroundValid, reliable and responsive Patient-Reported Outcome (PRO) questionnaires for young to middle-aged, physically active individuals with hip and groin pain are lacking.ObjectiveTo develop and validate a new PRO in accordance with the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) recommendations for use in young to middle-aged, physically active patients with long-standing hip and/or groin pain.MethodsPreliminary patient interviews (content validity) included 25 patients. Validity, reliability and responsiveness were evaluated in a clinical study including 101 physically active patients (50 women); mean age 36 years, range 18–63 years.ResultsThe Copenhagen Hip and Groin Outcome Score (HAGOS) consists of six separate subscales assessing Pain, Symptoms, Physical function in daily living, Physical function in Sport and Recreation, Participation in Physical Activities and hip and/or groin-related Quality of Life (QOL). Test–retest reliability was substantial, with intraclass correlation coefficients ranging from 0.82 to 0.91 for the six subscales. The smallest detectable change ranged from 17.7 to 33.8 points at the individual level and from 2.7 to 5.2 points at the group level for the different subscales. Construct validity and responsiveness were confirmed with statistically significant correlation coefficients (0.37–0.73, p < 0.01) for convergent construct validity and for responsiveness from 0.56 to 0.69, p < 0.01.ConclusionHAGOS has adequate measurement qualities for the assessment of symptoms, activity limitations, participation restrictions and QOL in physically active, young to middle-aged patients with long-standing hip and/or groin pain and is recommended for use in interventions where the patient's perspective and health-related QOL are of primary interest.Trial registrationClinicalTrials.govNCT00716729
Risk factors for patellar tendinopathy in competitive volleyball players
Authors: De Ridder R , Mahieu N , Reynaert L , Poppe W , Strubbe K , Cools A , Roosen P 
Published: April 2011

BackgroundPatellar tendinopathy (PT) is an important problem in a volleyball population. However, in order to optimize rehabilitation and prevention strategies, not all intrinsic risk factors are known. This study is the first study that takes the hip strength into account.ObjectiveThe objective is to identify some intrinsic risk factors of the lower limb for the development of PT in competitive volleyball players.DesignRetrospective.SettingEight male national volleyball teams participated in this study. Risk factors were assessed at the beginning of the season 2009–2010. By means of questionnaires, the participants injury history was documented.ParticipantsA total of 71 male players (25.1±4.5 years) were included. Players with a history of surgery and pain on the moment of testing were excluded.Assessment of risk factorsMuscle strength, muscle length and landing strategies were assessed.Main outcome measurementsThe strength of the hip muscles was measured with a hand-held dynamometer. Muscle length of gastrocnemius, soleus, hamstrings and quadriceps was determined by means of a plurimeter. A 2D video analyses was made of a vertical jump. Knee flexion angle, Q-angle and Ankle dorsiflexion angle during the landing were calculated.ResultsThe players with a history of PT (>6 months ago) displayed a significant greater ankle dorsiflexion ROM, a significant lower hip flexion strength and a significant shorter quadriceps. A logistic regression model indicated that a greater ankle dorsiflexion ROM and a lower hip flexion strength are predictors for occurrence of PT.ConclusionsIt can be concluded that a greater dorsiflexion ankle during landing and a lower hip flexion strength are associated with the occurrence of a PT. Future prospective studies should include, not only the knee, but also the hip and the ankle in their assessment.
Effect of altitude training on haematological variables in women volleyball players
Authors: Cueto-Martín B , de la Cruz-Márquez J C , de la Cruz-Campos J C , de la Cruz-Campos A 
Published: April 2011

BackgroundAthletes from many endurance disciplines include altitude training in their yearly training programme. In volleyball, it is necessary to clarify the haematological benefits and improvement in sports performance.ObjectiveTo investigate the influence of moderate altitude on haematological variables in a women's volleyball team (Honor Division – Spain).Design and settingWe assessed 14 elite female volleyball players for two weeks in normoxia (640 m above sea level), two weeks in relative hypoxia (2450 m, at the High Performance Center of Sierra Nevada, Granada, Spain) and two final weeks in normoxia again, during the volleyball preseason (August–September).Participants14 women (mean age 23±2.8 years; height: 184.9±6.9 cm; weight: 73.1±6.2 kg). All players who started the study completed it. None were taking dietary supplements, vitamins or exogenous iron. During the study, all players menstruated.InterventionsThe volleyball players trained twice daily (3 h/season). Blood samples were taken at 7-day intervals in normoxia and 72 h in hypoxia. Economy of effort was evaluated by the relationship between oxygen intake (Vo2) and running speed on a treadmill using sport-specific protocols. Blood samples were taken monthly during volleyball season.Independent Variable: Altitude.Dependent Variables: Haematological and VO2intake.ResultsHigher levels of haemoglobin (14.1±1.2 g/dl) and hematocrit (42.7±2.2%) were obtained at normoxia prealtitude, while the lowest levels were obtained in the first week post-altitude (12.9±1.8 g/dl; 38.9±2.3% respectively; p<0.05). After the stay at altitude, oxygen intake was increased (48.1±1.5 to 51.4±2.3 ml/kg/min; p<0.05).Conclusions2 weeks of moderate hypoxia improved the maximum oxygen intake but not the haemoglobin or hematocrit levels.
Long-term Holter ECG monitoring of volleyball players
Authors: de la Cruz-Campos J C , de la Cruz-Márquez J C , Cueto-Martín B , de la Cruz-Campos A 
Published: April 2011

BackgroundThe resting ECG can detect many cardiac abnormalities, but high levels of training to which athletes are subjected can trigger episodes of abnormal heart function, which should be evaluated by means of long-term records.ObjectiveThe purpose of the study was to detect the frequency and nature of rhythmic alterations in volleyball players during the late recovery period following a match.DesignRetrospective study.Setting and participants12 volleyball players, volunteers, from 18–32 years old (mean: 24.5±1.2 years), members of a First National Division team. All were declared fit for volleyball and had no ECG abnormalities. The subjects underwent Holter ECG recording before and immediately after a match. The Holter used was NORAV DXP-1000 model.InterventionsBoth the day before and after a match, the players did not train but did all work or academic activities normally. They were instructed to record their times of sleep and activity. Dependent variables: pertaining to heart rate, rhythm and ST space. Independent variable: physical exercise (match).ResultsThe average pre/post-match heart rates were 68.3±8.9 bpm when awake; 64.1±5.6 (p<0.01) and 62.8±7.7; 61.2±8.5 (p<0.01) when sleeping. Both before and after the match, 11 players (91%) had a mild or pronounced respiratory sinus arrhythmia. Isolated atrial or ventricular premature contractions were observed in 1 (8.3%), first-degree intermittent A-V blocks and second-degree A-V blocks with Wenckebach periods were observed in 1, high T-waves were found in 5 (41.6%), and high take-off of ST segments were found in 6 (50%).ConclusionsAfter the match, there are fewer pulsations recorded, there are more bradycardic rhythms and there are fewer arrhythmic events.
Electrocardiographic profile of volleyball players
Authors: de la Cruz-Márquez J C , Cueto-Martín B , de la Cruz-Campos J C , de la Cruz-Campos A 
Published: April 2011

BackgroundThe 12-lead ECG is not only necessary for diagnosing the sports aptitude of players, but it also provides information on their training condition and cardiovascular adaptations to exercise.ObjectiveTo determine the electrocardiographic adaptations of high-level volleyball players and relate them to their level of training.DesignRetrospective study over the course of 18 years, from 1992 to 2009. We analyzed the ECGs taken at the start of each season as part of routine medical test. We analyzed 1080 ECGs (15 players/18 years/4 teams – two male and two female).Setting and participantsMale and female youth and Honor Division teams from the same club. 180 women (94 youth, 86 senior) and 210 men (126 youth, 84 senior) (mean age, height, weight).InterventionIn August–September of each season, a resting ECG was taken for each player to determine pre-competitive fitness. Independent variables: sex, age, years of training. Dependent variables: P waves, QRS, T in duration and voltage and ECG evaluation (axes).ResultsECG/player Average: 5.6±1.9, FC resting: 66.3±3 bpm. Left ventricular hypertrophy: 38.95%±8.9; Right ventricular hypertrophy: 12.77%±3.4. Right Bundle Branch Block: 25.64%±8.3. Participants who required echocardiography: eight players: ST segment depression. five players: Inverted or flattened T wave in two or more leads. Three men and two women: Corrected QT interval prolongation in heart rate (QTc)> 0.44 s in men and> 0.46 s in women. Echocardiography ruled out organic disease. There were no differences in terms of years of training or level.ConclusionsElectrocardiographic adaptations in volleyball are similar to those in the literature for team sports. There was no pathological study and all were declared fit for the high-level sport.
The age and gender effects on heart rate in children school volleyball players from Bosnia and Herzegovina
Authors: Masala A , Bajraktarevic A , Miokovic M , Omerovic M , Rovcanin A , Sporisevic L 
Published: April 2011

BackgroundVolleyball is a fun sport for children that is easy to learn and can be played in a gym, at the beach, or on grass. Playing volleyball help improve child heart work, flexibility, balance and coordination. Some schools have volleyball teams for boys and girls. Heart rates can improve sports exercise and volleyball can make children stronger and healthier.ObjectiveThe purpose of this study was to examine accountability paediatrics systems operating in youth volleyball training sessions and to understand how those systems vary according to the instructional tasks and the nature of the information provided by paediatricians.Design, setting and participantsThe ECG recording was performed for 5 min at rest in seated, supine or supine with elevated legs body position on different days in girl and boy school volleyball players. Measurements were undertaken in a quiet room, air temperature ranging from 21 to 22°C, after and before volleyball games. The data was analyzed for 40 female and 40 male volleyball players ranging in age from 12 to 16 years, and other equal players and athletes in other sports of the same age and gender.MethodsSystematic medical observation strategies were used to describe and analyse paediatric tasks for heart rates presentation and task volleyball players in schools during paediatrics examinations. Statistical analyses were performed using the Sigmastat Programme 3.0 for windows package during period 2005–2009 in school players teams in Bosnia and Herzegovina.Main outcome measurementYoung female volleyball players are more vulnerable to sport injuries but similiar heart rates stabilizing works after volleyball games comparing than their boys counterparts.ResultsHeart rates after volleyball games and exercise were lower and better than other sports groups in both volleyball groups for girls and boys, too, without difference.ConclusionsFurther research needs to address issues of paediatricians' knowledge and conceptions related to volleyball instruction for heart works improvement. No differences were noted between heart rates after exercise in boys and girls volleyball school players, but better heart rates were observed in older age volleyball players when compared to other athletes such as tennis players and soccer or basketball players.
Factor structure differences of indicators for evaluating isometric leg extensors explosive force in female volleyball athletes and different trained female population
Authors: Ivanović J , Dopsaj M , Nešić G 
Published: April 2011

BackgroundAdequate leg extensors preparation is highly important especially in volleyball which involve several jumping techniques. Values of developed force in the function of time generated during the isometric (static) muscle contraction, with it's own F-t curve characteristics are the fundamental data on contractile ability.ObjectiveFactor structure differences of indicators for evaluating isometric leg extensors explosive force (RFDLEGEXTISO) regarding different trained female population will be examined in this research.Setting and participantsSample included 50 examinees: top level female volleyball players (Elite N=20), unspecific trained female athletes (Nonspec N=18) and untrained female (Control N=12).MethodsIn order to assess characteristics of the F-t isometric leg extensors force, tensiometric probe and standardized ‘seating leg extension’ test were used. The measurement range was defined by 11 variables regarding the contractile characteristics of the leg extensors isometric muscle force at the level of 100, 50, 30, 50–100% of maximal force (FmaxLEGEXTISO): rate of force development (RFD) analysed from the aspect of absolute and relative (allometric) values – the indicators of basic (RFDBASICLEGEXTISO, RFDallomLEGEXTISO), specific (RFD50%LEGEXTISO, RFDallomLEGEXTISO50%), special (RFD30%LEGEXTISO, RFDallomLEGEXTISO30%), at 50–100% (RFD50–100%LEGEXTISO) level of RFD, Synergy Index as a criterion of relation between RFDLEGEXTISO and FmaxLEGEXTISO at the basic level of 100% – IndexSNGBASIC, specific level of 50% – IndexSNGSPEC and special level of 30% – IndexSNGSPECIJ.ResultsFactor analysis set apart two factors in all the observed groups, which have explained 96.491% in Elite, 95.502% in Nonspec, 96.512% in Control of valid variance. The differences in structure and in number of parameters for separated factors were established especially between tested trained and untrained population. They can be explained with differences in muscle tissue and maximal nervous activation of muscles during the specific training, that is, adaptation to specific training.ConclusionsThe obtained results can possibly be used as an indicator of potential of leg explosiveness and jumping performances in volleyball players selection.
Study of extensor and flexor musculature in the knees of male and female volleyball players
Authors: Rodríguez-Ruiz D , Rodríguez-Matoso D , Quiroga M E , Sarmiento S , Da Silva-Grigoletto M E 
Published: April 2011

ObjectiveThe aim of the present study was to analyse differences in muscle response and mechanical characteristics of the vastus medialis (VM), rectus femoris (RF), vastus lateralis (VL) and biceps femoris (BF) in elite volleyball players of both sexes using tensiomyography (TMG).Setting47 players of nine nationalities playing in teams belonging to the men's and women's Spanish Superleagues (elite division) were assessed.Participants22 women (age 24.59±4.27 years; weight 72.14±10.06 kg; height 178.40±8.50 cm) and 25 men (age 25.04±4.29 years; weight 88.76±9.07 kg; height 194.71±7.84 cm).MethodsTMG was used to assess muscular response, muscular mechanical characteristics, and gender differences. For this purpose, the following variables were analysed: maximum radial displacement of muscle belly or maximum deformation (Dm), and normalised response speed (Vrn).ResultsThe findings show, both in men and women, a higher normalised response speed (Vrn) score in the VL and VM compared to the RF and BF. A marked lateral symmetry of maximum radial deformation or displacement of the muscle belly (Dm) was also observed in the musculature of the lower limbs, with no statistically-significant differences being detected in either men or women. There were, however, clear differences in terms of muscle response between male and female volleyball players: women displayed a more pronounced difference in the Vrn of the musculature responsible for extension (VM, RF and VL) and flexion (BF) of the knee joint than men.ConclusionsTMG proved to be a highly sensitive tool for detecting changes in lower limb muscle activity.