bluuebunny/crossref_metadata_2025_split huggingface dataset:
Corticosteroids Are Unable To Protect against Pseudorabies Virus-Induced Tissue Damage in the Developing Brain
Authors: Clase Amanda C. , Banfield Bruce W. 
Published: March 2003

ABSTRACT

After intraocular injection of the virulent pseudorabies virus (PRV) strain Becker into late-stage chicken embryos, the virus spreads and replicates in the brain, where severe edema and hemorrhaging follow. By contrast, the attenuated Bartha strain does not cause severe brain pathology despite viral replication and spread throughout the brain (B. W. Banfield, G. S. Yap, A. C. Knapp, and L. W. Enquist, J. Virol.
72:
4580-4588, 1998). These observations prompted us to explore the mechanism by which the virulent Becker strain mediates pathology in the chicken embryo central nervous system (CNS). To test the hypothesis that Becker infection induced an inflammatory response in the developing CNS, we examined the ability of the anti-inflammatory corticosteroid dexamethasone (Dex) to protect chicken embryos from PRV-induced brain damage. We found that Dex is not sufficient to protect the chicken embryo CNS from damage due to Becker infection. Surprisingly, systemic Dex delivery appeared to potentiate CNS damage, which was preceded by petechial hemorrhaging in the optic lobes. Taken together, these data suggest that the severe pathology elicited during the Becker infection is due not to immunopathology but to damage by the virus itself, possibly through the damage to or destruction of endothelial cells.
Localization of CD4 and CCR5 in Living Cells
Authors: Steffens Carolyn M. , Hope Thomas J. 
Published: March 2003

ABSTRACT
The events preceding human immunodeficiency virus fusion and entry are influenced by the concentration and distribution of receptor and coreceptor molecules on the cell surface. However, the extent to which these proteins colocalize with one another in the cell membrane remains unclear. Using high-resolution deconvolution fluorescent microscopy of living cells, we found that both CD4 and CCR5 accumulate in protruding membrane structures containing actin and ezrin. Although CD4 and CCR5 extensively colocalize in these structures, they do not exist in a stable complex.
Human Herpesvirus 6 Variant A Glycoprotein H-Glycoprotein L-Glycoprotein Q Complex Associates with Human CD46
Authors: Mori Yasuko , Yang Xuwei , Akkapaiboon Pilailuk , Okuno Toshiomi , Yamanishi Koichi 
Published: March 2003

ABSTRACT
Human CD46 is a cellular receptor for human herpesvirus 6 (HHV-6). Virus entry into host cells requires a glycoprotein H (gH)-glycoprotein L (gL) complex. We show that the CD46 ectodomain blocked HHV-6 infection and bound a complex of gH-gL and the 80-kDa U100 gene product, designated glycoprotein Q, indicating that the complex is a viral ligand for CD46.
Latent Membrane Protein 1 Inhibits Epstein-Barr Virus Lytic Cycle Induction and Progress via Different Mechanisms
Authors: Prince Stuart , Keating Sinead , Fielding Ceri , Brennan Paul , Floettmann Eike , Rowe Martin 
Published: March 2003

ABSTRACT
Epstein-Barr virus (EBV) is a potent growth-transforming agent of human B cells. It has previously been shown that viral latent membrane protein 1 (LMP1) is essential for EBV-induced transformation of normal B cells and contributes to maintenance of latency in vitro. Using the EBV-positive Burkitt's lymphoma line P3HR1-c16, which lacks LMP1 during latency and which can readily be activated into virus-productive lytic cycle, we found that LMP1 inhibits lytic cycle induction via the transcription factor NF-κB. In addition, LMP1 inhibits lytic cycle progress via two distinct NF-κB-independent mechanisms: one involving the cytosolic C-terminal activating regions and the other involving the transmembrane region of LMP1. These findings indicate that in B cells EBV self-limits its lytic cycle via three distinct LMP1-mediated mechanisms.
Epstein-Barr Virus Nuclear Antigen 2 Binds via Its Methylated Arginine-Glycine Repeat to the Survival Motor Neuron Protein
Authors: Barth Stephanie , Liss Michael , Voss Marc D. , Dobner Thomas , Fischer Utz , Meister Gunter , Grässer Friedrich A. 
Published: March 2003

ABSTRACT

Here we provide evidence that EBNA2 is methylated in vivo and that methylation of EBNA2 is a prerequisite for binding to SMN. We present SMN as a novel binding partner of EBNA2 by showing that EBNA2 colocalizes with SMN in nuclear gems and that both proteins can be coimmunoprecipitated from cellular extract. Furthermore, in vitro methylation of either wild-type EBNA2 or a glutathione
S
-transferase-EBNA2 fusion protein encompassing the arginine-glycine (RG) repeat element is necessary for in vitro binding to the Tudor domain of SMN. The recently shown functional cooperation of SMN and EBNA2 in transcriptional activation and the previous observation of a severely reduced transformation potential yet strongly enhanced transcriptional activity of an EBNA2 mutant lacking the RG repeat indicate that binding of SMN to EBNA2 is a critical step in B-cell transformation by Epstein-Barr virus.
Vigorous but Short-Term Gamma Interferon T-Cell Responses against a Dominant HLA-A*02-Restricted Measles Virus Epitope in Patients with Measles
Authors: Jaye Assan , Herberts Carla A. , Jallow Sabelle , Atabani Sowsan , Klein Michel R. , Hoogerhout Peter , Kidd Michael , van Els Cécile A. C. M. , Whittle Hilton C. 
Published: March 2003

ABSTRACTThe absolute and relative abundance of major histocompatibility complex class I-presented viral epitopes is important in the induction and maintenance of antiviral cytotoxic-T-lymphocyte (CTL) responses. We demonstrate that the supra-abundant HLA-A*0201-restricted peptide KLWESPQEI of the measles virus nonstructural C protein induces strong gamma interferon CD8+-T-cell responses in children with acute measles. However, longitudinal analysis indicates that these responses are only short-lived. Thus, some viral epitopes that can be immunodominant during primary infection may fail to establish memory CTL responses.
A Single Amino Acid Mutation in the PA Subunit of the Influenza Virus RNA Polymerase Promotes the Generation of Defective Interfering RNAs
Authors: Fodor Ervin , Mingay Louise J. , Crow Mandy , Deng Tao , Brownlee George G. 
Published: March 2003

ABSTRACT
An R638A mutation of the polymerase acidic protein (PA) subunit of the RNA polymerase of influenza A/WSN/33 virus results in severe attenuation of viral growth in cell culture by promoting the synthesis of defective interfering RNAs. We propose that R638A is an “elongation” mutant that destabilizes PA-RNA template interactions during elongation. A C453R mutation in PA can compensate for this defect, suggesting that amino acids C453 and R638 form part of the same domain.
The Processing of eIF4GI by Human Rhinovirus Type 2 2A
pro
: Relationship to Self-Cleavage and Role of Zinc
Authors: Glaser Walter , Triendl Andrea , Skern Tim 
Published: March 2003

ABSTRACT

The 2A proteinase (2A
pro
) of human rhinoviruses (HRVs) is a cysteine protease containing a structurally important zinc ion. In the viral polyprotein, the enzyme cleaves between the C terminus of VP1 and its own N terminus. 2A
pro
also processes the two isoforms of the cellular protein, eukaryotic initiation factor 4G (eIF4G). We have shown that mature HRV2 2A
pro
, when translated in vitro in rabbit reticulocyte lysates, efficiently cleaves eIF4GI, although the enzyme was not immediately active upon synthesis. Here, we examine the relationship between self-processing and eIF4GI cleavage. The onset of both reactions first occurred at least 10 min after initiation of protein synthesis. Furthermore, when self-processing was prevented by a specific mutation between VP1 and 2A
pro
, the VP1-2A
pro
precursor was essentially unable to cleave eIF4GI, implying that self-processing is a prerequisite for eIF4GI cleavage. 2A
pro
synthesized in the presence of a potent zinc chelator is inactive; however, upon addition of excess zinc, HRV2 2A
pro
rapidly gained activity. Finally, the presence of the zinc chelator in the culture medium can protect HeLa cells from HRV infection.
Human Rhinovirus 2A Proteinase Cleavage Sites in Eukaryotic Initiation Factors (eIF) 4GI and eIF4GII Are Different
Authors: Gradi Alessandra , Svitkin Yuri V. , Sommergruber Wolfgang , Imataka Hiroaki , Morino Shigenobu , Skern Tim , Sonenberg Nahum 
Published: March 2003

ABSTRACT

Several picornaviruses shut down host cellular protein synthesis by proteolytic cleavage of the eukaryotic initiation factor (eIF) 4GI and eIF4GII isoforms. Viral RNA translation is maintained by a cap-independent mechanism. Here, we identify the human rhinovirus 2 2A
pro
cleavage site in eIF4GII in vitro as PLLNV
699
*GSR; this sequence lies seven amino acids C-terminal to the cleavage site previously identified in eIF4GI (LSTR681*GPP).
The Barrier-to-Autointegration Factor Is a Component of Functional Human Immunodeficiency Virus Type 1 Preintegration Complexes
Authors: Lin Chou-Wen , Engelman Alan 
Published: March 2003

ABSTRACT
Retroviral integration in vivo is mediated by preintegration complexes (PICs) derived from infectious virions. In addition to the integrase enzyme and cDNA substrate, PICs contain a variety of viral and host cell proteins. Whereas two different cell proteins, high-mobility group protein A1 (HMGA1) and the barrier-to-autointegration factor (BAF), were identified as integration cofactors based on activities in in vitro PIC assays, only HMGA1 was previously identified as a PIC component. By using antibodies against known viral and cellular PIC components, we demonstrate here functional coimmunoprecipitation of endogenous BAF protein with human immunodeficiency virus type 1 (HIV-1) PICs. Since integrase protein and integration activity were also coimmunoprecipitated by anti-BAF antibodies, we conclude that BAF is a component of HIV-1 PICs. These data are consistent with the model that BAF functions as an integration cofactor in vivo.
A Novel Antiviral Intervention Results in More Accurate Assessment of Human Immunodeficiency Virus Type 1 Replication Dynamics and T-Cell Decay In Vivo
Authors: Markowitz Martin , Louie Michael , Hurley Arlene , Sun Eugene , Di Mascio Michele , Perelson Alan S. , Ho David D. 
Published: March 2003

ABSTRACT

Mathematical models provide an understanding of in vivo replication kinetics of human immunodeficiency virus type 1 (HIV-1). With a novel intervention designed for increased potency, we have more accurately deduced the half-lives of virus-producing CD4
+
T cells, 0.7 day, and the generation time of HIV-1 in vivo, approximately 2 days, confirming the dynamic nature of HIV-1 replication.
Effects of prior concentric training on eccentric exercise induced muscle damage
Authors: Gleeson N , Eston R , Marginson V , McHugh M 
Published: March 2003

Background:Exercise induced muscle damage (EIMD) from strenuous unaccustomed eccentric exercise is well documented. So too is the observation that a prior bout of eccentric exercise reduces the severity of symptoms of EIMD. This has been attributed to an increase in sarcomeres in series. Recent studies have suggested that prior concentric training increases the susceptibility of muscle to EIMD following eccentric exercise. This has been attributed to a reduction of sarcomeres in series, which decreases muscle compliance and changes the length-tension relation of muscle contraction.Objective:To assess the effects of prior concentric training on the severity of EIMD.Methods:Four men and four women (mean (SD) age 21.1 (0.8) years) followed a four week concentric training programme. The elbow flexor musculature of the non-dominant arm was trained at 60% of one repetition maximum dynamic concentric strength performance, three times a week, increasing to 70% by week 3. After three days of rest, participants performed 50 maximal isokinetic eccentric contractions on both arms. All participants gave written informed consent before taking part in this study, which was approved by the school ethics committee. Strength, relaxed arm angle (RAA), arm circumference, and soreness on active extension and flexion were recorded immediately before eccentric exercise, one hour after, and at 24 hour intervals for three days. Data were analysed with fully repeated measures analyses of variance.Results:Strength retention was significantly (p<0.01) greater in the control arm than the trained arm (84.0 (13.7)%, 90.4 (14.7)%, 95.2 (10.5)%, 103.5 (7.6)%v75.5 (11.3)%, 77.6 (15.3)%, 80.1 (13.9)%, 80.9 (12.5)%) at one, 24, 48, and 72 hours respectively. Similarly, soreness was greater in the trained arm (0.7 (0.6), 3.1 (1.4), 3.0 (1.5), 1.9 (2.3)) than in the untrained arm (0 (0.2), 1.6 (1.3), 1.4 (0.6), 0.6 (0.4)) at one, 24, 48, and 72 hours respectively (p<0.05). Concentric training induced a significant reduction in RAA (165.2 (6.7)°v157.3 (4.9)°) before the eccentric exercise bout (p<0.01). This was further reduced and remained lower in the trained arm at all time points after the eccentric exercise (p<0.01). The arm circumference of the concentrically trained arm was significantly greater than baseline (p<0.05) at 72 hours (30.3 (2.9)v29.8 (3.3) cm).Conclusions:These findings extend the understanding of the effects of prior concentric training in increasing the severity of EIMD to an upper limb exercise model. The inclusion of concentric conditioning in rehabilitation programmes tends to exacerbate the severity of EIMD in subsequent unaccustomed exercise. However, where concentric conditioning is indicated clinically, the net effect of conditioning outcome and EIMD may still confer enhanced strength performance and capability to dynamically stabilise a joint system.
Effect of verbal instructions on muscle activity and risk of injury to the anterior cruciate ligament during landing
Authors: Cowling E J , Steele J R , McNair P J 
Published: March 2003

Background:Minimising the likelihood of injury to the anterior cruciate ligament (ACL) during abrupt deceleration requires proper synchrony of the quadriceps and hamstring muscles. However, it is not known whether simple verbal instructions can alter landing muscle activity to protect the knee.Objective:To assess the efficacy of verbal instructions to alter landing muscle activity.Methods:Twenty four athletes landed abruptly in single limb stance. Sagittal plane motion was recorded with an optoelectric device, and ground reaction force and surface electromyographic data were recorded for the rectus femoris, vastus lateralis, biceps femoris, and semimembranosus muscles. Subjects performed 10 landings per condition: normal landing (N); repeat normal landing (R); landing after instruction to increase knee flexion (K); and landing after instruction to recruit hamstring muscles earlier (M). Muscle bursts immediately before landing were analysed relative to initial foot-ground contact (IC).Results:The K condition resulted in significantly (p⩽0.05) greater knee flexion at IC compared with the other conditions. The M condition did not result in earlier hamstring muscle activity, but instead caused significantly (p⩽0.05) earlier rectus femoris onset relative to IC, with a similar trend for the vastus lateralis. As these muscles are ACL antagonists, earlier onset times would be detrimental to the ACL.Conclusions:Subjects successfully increased knee flexion during landing following the K condition instruction. However, further research is warranted to establish the efficacy of more extensive lower limb muscle retraining programmes to ensure landings that decrease susceptibility to ACL injury.
Feasibility of power-type strength training for middle aged men and women: self perception, musculoskeletal symptoms, and injury rates
Authors: Surakka J , Aunola S , Nordblad T , Karppi S-L , Alanen E 
Published: March 2003

Objectives:To examine the feasibility of a power-type strength training programme for middle aged men and women, the impact of the training programme on perceived health and fitness and on knee and low back symptoms, and the rate of exercise induced injuries.Methods:A total of 154 voluntary, healthy, sedentary men and women participated in a training programme lasting about four months. The explosive force of leg extensor muscles was measured by means of standing long jumps and vertical squat jumps. Perceived health, perceived fitness, and low back and knee symptoms were assessed before and after the intervention by using a questionnaire. Musculoskeletal disorders and exercise induced injuries were reported during the training programme.Results:Perceived fitness improved in both men (p<0.01) and women (p<0.0001), but perceived health only in women (p<0.01). Men with increased explosive force in squat jumping also showed better perceived health (p<0.05), and women with increased explosive force in standing long jump showed better perceived fitness (p<0.05). Exercising men who had increased knee symptoms had significantly higher body mass index than the other exercising men (p<0.05). The exercise induced injury rate was 19% in men and 6% in women.Conclusions:Successful completion of the exercise programme, together with the increased physical activity and relatively low injury rate, may have contributed to the participants finding the exercise programme positive and stimulating and believing that their health and fitness had improved. The low rate of musculoskeletal injury suggests that this type of supervised exercise programme is feasible for untrained middle aged people.
Occurrence of acute lower limb injuries in artistic gymnasts in relation to event and exercise phase
Authors: Kirialanis P , Malliou P , Beneka A , Giannakopoulos K 
Published: March 2003

Objectives:To record the incidence of lower limb injuries (acute and overuse syndromes) in Greek artistic gymnasts in relation to the event and exercise phase.Methods:A total of 162 gymnasts (83 male and 79 female athletes) participating in the Greek artistic gymnastic championships were observed weekly for the 1999–2000 season.Results:Ninety three (61.6%) acute injuries and 58 (38.4%) overuse syndromes were recorded. The most common anatomical location was the ankle (69 cases, 45.7%), followed by the knee (40 cases, 26.5%). The rate of mild injuries was 26.6% (25 cases), that of moderate injuries was 44% (41 cases), and that of major injuries was 29% (27 cases). The incidence of injury to the ankle and knee was significantly higher in the floor exercise, especially during the landing phase, than in the other events.Conclusions:By its nature, gymnastics predisposes to acute injuries, but up to 75% are mild or moderate. Special attention should be paid to the floor exercise, especially the landing phase.
Effects of electrical stimulation on Vo2kinetics and delta efficiency in healthy young men
Authors: Pérez M , Lucia A , Santalla A , Chicharro J L 
Published: March 2003

Objective:To determine the effects of electrical stimulation (ES) on oxygen uptake (Vo2) kinetics and delta efficiency (DE) during gradual exercise. The hypothesis was that ES would attenuate the Vo2-workload relation and improve DE.Methods:Fifteen healthy, untrained men (mean (SD) age 22 (5) years) were selected. Ten were electrostimulated on both quadriceps muscles with a frequency of 45–60 Hz, with 12 seconds of stimulation followed by eight seconds recovery for a total of 30 minutes a day, three days a week for six weeks. The remaining five subjects were assigned to a control group. A standardised exercise test on a cycle ergometer (ramp protocol, workload increases of 20 W/min) was performed by each subject before and after the experimental period. The slope of the Vo2-power output (W) relation (ΔVo2/ΔW) and DE were calculated in each subject at moderate to high intensities (above the ventilatory threshold—that is, from 50–60% to 100% Vo2max).Results:The mean (SEM) values for ΔVo2/ΔW and DE had significantly decreased and increased respectively after the six week ES programme (p<0.05; 9.8 (0.2)v8.6 (0.5) ml O2/W/min respectively and 27.7 (0.9)v31.5 (1.4)% respectively).Conclusions:ES could be used as a supplementary tool to improve two of the main determinants of endurance capacity, namely Vo2kinetics and work efficiency.
Development of predictive equations for body density of sumo wrestlers using B-mode ultrasound for the determination of subcutaneous fat thickness
Authors: Saito K , Nakaji S , Umeda T , Shimoyama T , Sugawara K , Yamamoto Y 
Published: March 2003

Objective:To develop an equation for predicting the body density of sumo wrestlers.Methods:The following were measured: subcutaneous fat thickness measured at nine sites using B-mode ultrasound equipment; circumference at seven sites; hand to leg bioelectrical impedance. The subjects consisted of 24 college sumo wrestlers (mean age 19.7 years, mean body weight 111.2 kg) and 24 matched obese controls (mean age 19.1 years and mean body weight 111.2 kg). In addition, body density was measured by the underwater weighing method, and the percentage of fat was calculated from the measured body density.Results:Linear regression analysis was used to estimate the relation between body density and other variables, and a predictive equation for the body density was derived: y = 1.088−0.00036 × (fat thickness at nine sites) (r2= 0.90) for the sumo wrestler group and y = 1.083−0.00033 × (fat thickness at nine sites) (r2= 0.91) for the control group. A multiple regression analysis was performed using the body density as the objective variable, and other measured items as the explanatory variables. This was used to derive a predictive equation: y = 1.121−0.00038 × (fat thickness of abdomen)−0.00043 × (circumference of hips)−0.00142 × (fat thickness of triceps) (r2= 0.94) for the sumo wrestler group, and y = 1.076−0.00070 × (fat thickness of abdomen)−0.00140 × (fat thickness of tibialis) (r2= 0.91) for the control group. The difference between the two equations was due to the difference in body fat distribution. Neither of these predictive equations is applicable to non-overweight non-athletes.Conclusion:This is the first predictive equation developed for the body density of sumo wrestlers.
Are ultrasound and magnetic resonance imaging of value in assessment of Achilles tendon disorders? A two year prospective study
Authors: Khan K M , Forster B B , Robinson J , Cheong Y , Louis L , Maclean L , Taunton J E 
Published: March 2003

Objectives:To (a) compare ultrasound (US; including grey scale and colour and power Doppler) and magnetic resonance imaging (MRI; with high resolution and fat saturation sequences) with a clinical yardstick in the evaluation of chronic Achilles tendinopathy, and (b) examine whether either imaging method predicted 12 and 24 month clinical outcome.Methods:Forty five patients with symptoms in 57 Achilles tendons were diagnosed with tendinopathy by an experienced sports medicine doctor. All patients underwent US examination (12 MHz probe) with colour and power Doppler, and 25 consecutive patients also underwent MRI with high resolution T1 weighted and STIR sequences.Results:US identified abnormal morphology in 37 of the 57 symptomatic tendons (65%) and normal morphology in 19 of 28 asymptomatic tendons (68%). Baseline US findings did not predict 12 month clinical outcome. The addition of colour and power Doppler did not improve the diagnostic performance of US. MRI identified abnormal morphology in 19 of 34 symptomatic tendons (56%) and normal morphology in 15 of 16 asymptomatic tendons (94%). Lesser grades of MR signal abnormality at baseline were associated with better clinical status at 12 month follow up.Conclusions:US and MRI show only moderate correlation with clinical assessment of chronic Achilles tendinopathy. Graded MRI appearance was associated with clinical outcome but US was not.