bluuebunny/crossref_metadata_2025 huggingface dataset:
A Synthetic E7 Gene of Human Papillomavirus Type 16 That Yields Enhanced Expression of the Protein in Mammalian Cells and Is Useful for DNA Immunization Studies
Authors: Cid-Arregui Angel , Juárez Victoria , Hausen Harald zur
Published: March 2003

A synthetic E7 gene of human papillomavirus (HPV) type 16 was generated that consists entirely of preferred human codons. Expression analysis of the synthetic E7 gene in human and animal cells showed levels of E7 protein 20- to 100-fold higher than those obtained with wild-type E7. Enhanced expression of E7 protein resulted from highly efficient translation, as well as increased stability of the E7 mRNA due to its codon optimization. Higher levels of E7 protein in cells transfected with synthetic E7 correlated with significant loss of cell viability in various human cell lines. In contrast, lower E7 protein expression driven by the wild-type gene resulted in a slight induction of cell proliferation. Furthermore, mice inoculated with plasmids expressing the synthetic E7 gene produced significantly higher levels of E7 antibodies than littermates injected with wild-type E7, suggesting that synthetic E7 may be useful for DNA immunization studies and the development of genetic vaccines against HPV-16. In view of these results, we hypothesize that HPVs may have retained a pattern of G + C content and codon usage distinct from that of their host cells in response to selective pressure. Thus, the nonhuman codon bias may have been conserved by HPVs to prevent compromising viability of the host cells by excessive viral early protein expression, as well as to evade the immune system.
Resting CD4
+
T Lymphocytes but Not Thymocytes Provide a Latent Viral Reservoir in a Simian Immunodeficiency Virus-
Macaca nemestrina
Model of Human Immunodeficiency Virus Type 1-Infected Patients on Highly Active Antiretroviral Therapy
Authors: Shen Anding , Zink M. Christine , Mankowski Joseph L. , Chadwick Karen , Margolick Joseph B. , Carruth Lucy M. , Li Ming , Clements Janice E. , Siliciano Robert F.
Published: March 2003

Despite suppression of viremia in patients on highly active antiretroviral therapy (HAART), human immunodeficiency virus type 1 persists in a latent reservoir in the resting memory CD4
+
T lymphocytes and possibly in other reservoirs. To better understand the mechanisms of viral persistence, we established a simian immunodeficiency virus (SIV)-macaque model to mimic the clinical situation of patients on suppressive HAART and developed assays to detect latently infected cells in the SIV-macaque system. In this model, treatment of SIV-infected pig-tailed macaques (
Macaca nemestrina
) with the combination of 9-R-(2-phosphonomethoxypropyl)adenine (PMPA; tenofovir) and beta-2′,3′-dideoxy-3′-thia-5-fluorocytidine (FTC) suppressed the levels of plasma virus to below the limit of detection (100 copies of viral RNA per ml). In treated animals, levels of viremia remained close to or below the limit of detection for up to 6 months except for an isolated “blip” of detectable viremia in each animal. Latent virus was measured in blood, spleen, lymph nodes, and thymus by several different methods. Replication-competent virus was recovered after activation of a 99.5% pure population of resting CD4
+
T lymphocytes from a lymph node of a treated animal. Integrated SIV DNA was detected in resting CD4
+
T cells from spleen, peripheral blood, and various lymph nodes including those draining the gut, the head, and the limbs. In contrast to the wide distribution of latently infected cells in peripheral lymphoid tissues, neither replication-competent virus nor integrated SIV DNA was detected in thymocytes, suggesting that thymocytes are not a major reservoir for virus in pig-tailed macaques. The results provide the first evidence for a latent viral reservoir for SIV in macaques and the most extensive survey of the distribution of latently infected cells in the host.
Varicella-Zoster Virus Productively Infects Mature Dendritic Cells and Alters Their Immune Function
Authors: Morrow Gavin , Slobedman Barry , Cunningham Anthony L. , Abendroth Allison
Published: March 2003

Mature dendritic cells (DCs) are potent antigen-presenting cells essential for initiating successful antiviral immune responses and would therefore serve as an ideal target for viruses seeking to evade or delay the immune response by disrupting their function. We have previously reported that VZV productively infects immature DCs (A. Abendroth, G. Morrow, A. L. Cunningham, and B. Slobedman, J. Virol. 75:6183-6192, 2001), and in the present study we assessed the ability of VZV to infect mature DCs. Mature DCs were generated from immature monocyte-derived DCs by lipopolysaccharide treatment before being exposed to VZV-infected fibroblasts. On day 4 postexposure, flow cytometry analysis revealed that 15 to 45% of mature DCs were VZV antigen positive, and immunofluorescent staining together with infectious-center assays demonstrated that these cells were fully permissive for the complete VZV replicative cycle. VZV infection of mature DCs resulted in a selective downregulation of cell surface expression of the functionally important immune molecules major histocompatibility complex (MHC) class I, CD80, CD83, and CD86 but did not alter MHC class II expression. Immunofluorescent staining showed that the downregulation of cell surface CD83 was concomitant with a retention of CD83 in cytoplasmic vesicles. Importantly, VZV infection of mature DCs significantly reduced their ability to stimulate the proliferation of allogeneic T lymphocytes. These data demonstrate that mature DCs are permissive for VZV and that infection of these cells reduces their ability to function properly. Thus, VZV has evolved yet another immune evasion strategy that would likely impair immunosurveillance and enhance the chances for lifelong persistence in the human population.
Adenovirus Dodecahedron Allows Large Multimeric Protein Transduction in Human Cells
Authors: Fender P. , Schoehn G. , Foucaud-Gamen J. , Gout E. , Garcel A. , Drouet E. , Chroboczek J.
Published: March 2003

Adenovirus dodecahedron is a virus-like particle composed of only two viral proteins of human adenovirus serotype 3 that are responsible for virus attachment and internalization. We show here that this dodecameric particle, devoid of genetic information, efficiently penetrates human cells and can deliver large multimeric proteins such as immunoglobulins.
A Moloney Murine Leukemia Virus-Based Retrovirus with 4070A Long Terminal Repeat Sequences Induces a High Incidence of Myeloid as Well as Lymphoid Neoplasms
Authors: Wolff Linda , Koller Richard , Hu Xinrong , Anver Miriam R.
Published: March 2003

Retroviruses can be used to accelerate hematopoietic cancers predisposed to neoplastic disease by prior genetic manipulations such as in transgenic or knockout mice. The virus imparts a second neoplastic “hit,” providing evidence that the initial hit is transforming. In the present study, a unique retrovirus was developed that can induce a high incidence of myeloid disease and has a broad host range. This agent is a Moloney murine leukemia virus (Mo-MuLV)-based virus that has most of the U3 region of the long terminal repeat (LTR) replaced with that of retrovirus 4070A. Like Mo-MuLV, this virus, called MOL4070LTR, is NB-tropic and not restricted byFv1allelles. MOL4070LTR causes myeloid leukemias in ca. 50% of mice, a finding in contrast to Mo-MuLV, which induces almost exclusively lymphoid disease. The data suggest that the LTR of the 4070A virus expands the tissue tropism of the disease to the myeloid lineage. Interesting, MCF recombinant envelope was expressed in the lymphoid but not the myeloid neoplasms of BALB/c mice. This retrovirus has the potential for accelerating myeloid disease in genetically engineered mice.
Murine Coronavirus-Induced Hepatitis: JHM Genetic Background Eliminates A59 Spike-Determined Hepatotropism
Authors: Navas Sonia , Weiss Susan R.
Published: March 2003

Recombinant murine coronaviruses, differing only in the spike gene and containing the strain A59 (moderately hepatotropic) and JHM (neurotropic) spike genes in the background of the JHM genome, were compared for the ability to replicate in the liver and induce hepatitis in weanling C57BL/6 mice. Interestingly, expression of the A59 spike glycoprotein within the background of the neurotropic JHM strain does not reproduce the A59 hepatotropic phenotype. Thus, the JHM genetic background plays a dominant role over the spike in the determination of hepatotropism.
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

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

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

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

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

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

The 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

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

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

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

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

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.
Claims for the anabolic effects of growth hormone: a case of the Emperor’s new clothes?
Authors: Rennie M J
Published: March 2003

This review examines the evidence that growth hormone has metabolic effects in adult human beings. The conclusion is that growth hormone does indeed have powerful effects on fat and carbohydrate metabolism, and in particular promotes the metabolic use of adipose tissue triacylglycerol. However, there is no proof that net protein retention is promoted in adults, except possibly of connective tissue. The overexaggeration of the effects of growth hormone in muscle building is effectively promoting its abuse and thereby encouraging athletes and elderly men to expose themselves to increased risk of disease for little benefit.
Are activity promotion interventions based on the transtheoretical model effective? A critical review
Authors: Adams J , White M
Published: March 2003

The health benefits of physical activity are well documented yet 70% of adults remain sedentary. It has been suggested that inverventions based on the transtheoretical model of behaviour change (TTM) may be useful in promoting physical activity. Published work on the effectiveness of such inteventions is therefore critically reviewed. Although there is evidence that TTM based activity promotion interventions are effective in promoting activity adoption, initial results on longer term adherence are disappointing.
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.
Effect of cycling cadence on subsequent 3 km running performance in well trained triathletes
Authors: Bernard T , Vercruyssen F , Grego F , Hausswirth C , Lepers R , Vallier J-M , Brisswalter J
Published: March 2003

Objectives:To investigate the effect of three cycling cadences on a subsequent 3000 m track running performance in well trained triathletes.

Methods:Nine triathletes completed a maximal cycling test, three cycle-run succession sessions (20 minutes of cycling + a 3000 m run) in random order, and one isolated run (3000 m). During the cycling bout of the cycle-run sessions, subjects had to maintain for 20 minutes one of the three cycling cadences corresponding to 60, 80, and 100 rpm. The metabolic intensity during these cycling bouts corresponded approximately to the cycling competition intensity of our subjects during a sprint triathlon (> 80% V̇o2max).

Results:A significant effect of the prior cycling exercise was found on middle distance running performance without any cadence effect (625.7 (40.1), 630.0 (44.8), 637.7 (57.9), and 583.0 (28.3) seconds for the 60 rpm run, 80 rpm run, 100 rpm run, and isolated run respectively). However, during the first 500 m of the run, stride rate and running velocity were significantly higher after cycling at 80 or 100 rpm than at 60 rpm (p<0.05). Furthermore, the choice of 60 rpm was associated with a higher fraction of V̇o2max sustained during running compared with the other conditions (p<0.05).

Conclusions:The results confirm the alteration in running performance completed after the cycling event compared with the isolated run. However, no significant effect of the cadence was observed within the range usually used by triathletes.
Effect of wearing an ice cooling jacket on repeat sprint performance in warm/humid conditions
Authors: Duffield R , Dawson B , Bishop D , Fitzsimons M , Lawrence S
Published: March 2003

Objective:To examine the effect of cooling the skin with an ice jacket before and between exercise bouts (to simulate quarter and half time breaks) on prolonged repeat sprint exercise performance in warm/humid conditions.

Methods:After an initial familiarisation session, seven trained male hockey players performed two testing sessions (seven days apart), comprising an 80 minute intermittent, repeat sprint cycling exercise protocol inside a climate chamber set at 30°C and 60% relative humidity. On one occasion a skin cooling procedure was implemented (in random counterbalanced order), with subjects wearing an ice cooling jacket both before (for five minutes) and in the recovery periods (2 × 5 min and 1 × 10 min) during the test. Measures of performance (work done and power output on each sprint), heart rates, blood lactate concentrations, core (rectal) and skin temperatures, sweat loss, perceived exertion, and ratings of thirst, thermal discomfort, and fatigue were obtained in both trials.

Results:In the cooling condition, chest (torso) skin temperature, thermal discomfort, and rating of thirst were all significantly lower (p<0.05), but no significant difference (p>0.05) was observed between conditions for measures of work done, power output, heart rate, blood lactate concentration, core or mean skin temperature, perceived exertion, sweat loss, or ratings of fatigue. However, high effect sizes indicated trends to lowered lactate concentrations, sweat loss, and mean skin temperatures in the cooling condition.

Conclusions:The intermittent use of an ice cooling jacket, both before and during a repeat sprint cycling protocol in warm/humid conditions, did not improve physical performance, although the perception of thermal load was reduced. Longer periods of cooling both before and during exercise (to lower mean skin temperature by a greater degree than observed here) may be necessary to produce such a change.
Football boot insoles and sensitivity to extent of ankle inversion movement
Authors: Waddington G , Adams R
Published: March 2003

Background:The capacity of the plantar sole of the foot to convey information about foot position is reduced by conventional smooth boot insoles, compared with barefoot surface contact.

Objective:To test the hypothesis that movement discrimination may be restored by inserting textured replacement insoles, achieved by changing footwear conditions and measuring the accuracy of judgments of the extent of ankle inversion movement.

Methods:An automated testing device, the ankle movement extent discrimination apparatus (AMEDA), developed to assess active ankle function in weight bearing without a balance demand, was used to test the effects of sole inserts in soccer boots. Seventeen elite soccer players, the members of the 2000 Australian Women’s soccer squad (34 ankles), took part in the study. Subjects were randomly allocated to start testing in: bare feet, their own football boots, own football boot and replacement insole, and on the left or right side. Subjects underwent six 50 trial blocks, in which they completed all footwear conditions. The sole inserts were cut to size for each foot from textured rubber “finger profile” sheeting.

Results:Movement discrimination scores were significantly worse when subjects wore their football boots and socks, compared with barefoot data collected at the same time. The substitution of textured insoles for conventional smooth insoles in the football boots was found to restore movement discrimination to barefoot levels.

Conclusions:The lower active movement discrimination scores of athletes when wearing football boots with smooth insoles suggest that the insole is one aspect of football boot and sport shoe design that could be modified to provide the sensory feedback needed for accurate foot positioning.
Surgical management of large rotator cuff tears combined with instability in elite rugby football players
Authors: Goldberg J A , Chan K Y , Best J P , Bruce W J M , Walsh W , Parry W
Published: March 2003

Large rotator cuff tears are extremely uncommon in young people and when they occur they may be associated with shoulder instability. This paper reports on a series of six elite rugby union and rugby league footballers who presented with shoulder instability and large rotator cuff tears. They were treated with a two stage procedure: an open rotator cuff repair followed by an open shoulder stabilisation some 10 weeks later. All had successful outcomes. The paper also highlights the risk of tearing the rotator cuff when a patient continues to play contact sport with an untreated unstable shoulder.
Surgical repair of a chronic rupture of the rectus femoris muscle at the proximal musculotendinous junction in a soccer player
Authors: Straw R , Colclough K , Geutjens G
Published: March 2003

A rare case is presented of a longstanding rupture of the rectus femoris muscle at the proximal musculotendinous junction in a semiprofessional soccer player. Its different and unique presentation, the surgical repair, and the remarkable functional recovery are discussed.
Radial nerve palsy in an elite bodybuilder
Authors: Ng A B Y , Borhan J , Ashton H R , Misra A N , Redfern D R M
Published: March 2003

A case is reported of high radial nerve palsy in an elite bodybuilder caused by an extrinsic mass effect of muscular hypertrophy. Surgical decompression resulted in complete clinical resolution.
Radiation effect on MHD free-convective flow of a gas past a semi-infinite vertical plate with variable thermophysical properties for high-temperature differences
Authors: Aboeldahab E M , El Gendy M S
Published: March 2003

Radiation effects in the presence of a uniform transverse magnetic field on the free-convective steady laminar boundary-layer flow, past a semi-infinite vertical plate, for high-temperature differences are studied. The fluid density and the thermal conductivity are assumed to vary linearly with temperature. The fluid viscosity is assumed to vary as a reciprocal of a linear function of temperature. The nonlinear boundary-layer equations, governing the problem under consideration, are solved numerically by applying an efficient numerical technique based on the shooting method. The effects of the magnetic field M, the temperature ratio parameter θw, the thermal conductivity parameter S, the viscositytemperature parameter θr, and the radiation parameter N are examined on the velocity and temperature distributions as well as the coefficient of heat flux and the shearing stress at the plate.

PACS No.: 44.40+a
Effect of cobalt 60 and 1 MeV electron irradiation on silicon photodiodes/solar cells
Authors: Saad A M
Published: March 2003

Using 1060 krad doses of cobalt 60 gamma radiation, the effect of simulated space radiation on 1 mm2 active area silicon photodiodes with a sapphire window is studied. The diodes will be used to control the laser output of a space experiment in geostationary orbit. The effect of 1 MeV electron irradiation with various fluences on 100 mm2 silicon photodiodes/solar cells, which were used to control the attitude of a satellite in space, is also studied here. Fluences ranging from 3 x 1014 to 1 x 1015 cm2 of 1 MeV energy, caused a decrease in the short-circuit current, i.e., increasing the percentage of deterioration from 12% to 20% at a room-temperature measurement. Exposure to the gamma irradiation yields almost no degradation for the electro-optical performance of the devices. The manufacturing processes of the detectors and their electro-optical IV characteristics such as fill factor, responsivity, and dark current are presented here. Electro-optical tests were also done at intermediate levels of irradiation. High stability and high quality of the photodiodes were achieved prior to and after irradiation.

PACS No.: 84.60J
The light-front Hamiltonian and BRST formulations of a two-dimensional AbelianHiggs model
Authors: Kulshreshtha U
Published: March 2003

The Hamiltonian and BRST formulations of an AbelianHiggs model in one-space one-time dimensions are investigated in the light-front frame under some specific gauge choices.

PACS Nos.: 03.65+, 03.70+k, 11.10lm, 11.10Ef, and 11.30Rd
Hamiltonian and BRST formulations of a gauge-invariant chiral Schwinger model with the Faddeevian regularization
Authors: Kulshreshtha U
Published: March 2003

The Hamiltonian and BRST formulations of a gauge-invariant chiral Schwinger model with the Faddeevian regularization due to Mukhopadhyay and Mitra in one-space one-time dimensions (obtained by the inclusion of an appropriate WessZumino term in the action of the originally gauge-noninvariant model due to Mitra) are investigated under some specific gauge choices in the usual instant form of dynamics (on the hyperplanes x0 = constant). The physical contents of the original gauge-noninvariant theory are recovered from that of this gauge-invariant theory under a special choice of gauge, and the quantum equivalence of the two quantized theories is established.

PACS Nos.: 03.65+, 03.70+, 11.10lm, 11.10Ef, and 11.30Rd
MHD free convection flow of a micropolar fluid past a vertical porous plate
Authors: Helmy K A , Idriss H F , Kassem S E
Published: March 2003

The present work is concerned with the unsteady flow of an incompressible, viscous, conducting micropolar fluid, through a porous medium, over an infinite plate that is started into motion in its own plane by an impulse. A uniform magnetic field acts in a direction perpendicular to the plate. The governing equations are solved using a state space approach and the inversion of the Laplace transform is carried out, using a numerical approach. The technique is applied to a heated-plate problem and to a problem pertaining to a plate under uniform heating. Numerical results concerning temperature (for both problems), velocity, and microrotation are given and are illustrated graphically.

PACS Nos.: 47.00, 65.00, 47.50, 76.00
A theoretical model analysis of the sudden narrow temperature-layer formation observed in the ALOHA-93 Campaign
Authors: Hur H , Huang T Y , Zhao Z , Karunanayaka P , Tuan T F
Published: March 2003

The behavior of temperature and wind profiles observed on 21 October 1993 in the ALOHA-93 Campaign is theoretically and numerically analyzed. A sudden temperature rise took place in a very narrow vertical region (34 km) at about 87 km. Simultaneously observed radar wind profiles and mesospheric airglow wave structures that show a horizontal phase speed of 35 m/s and a period of about half an hour strongly suggest that a critical level may occur in the proximity of that altitude and that the energy dissipation due to the interaction of the gravity wave with the critical level causes the temperature rise. The numerical model used is a solution to the gravity wave  mean-flow interaction in the critical layer, including a simple cooling mechanism and a wave-energy dissipation simulated by the "optical model" technique. The solutions for the temperature variations so obtained show good agreement with the observed temperature profiles at different times, providing a quantitative explanation for the temperature inversion layer as a phenomenon of gravity wave  critical layer interaction.

PACS Nos.: 91.10V, 94.10D
High quantum efficiency of UV-enhanced silicon photodiodes
Authors: Saad A M
Published: March 2003

High quantum efficiency UV-enhanced (P+nn+) silicon photodiodes have been developed using ion implantation, rapid thermal processing, and a thin silicon dioxide film as an antireflection/passivation layer. The unbiased devices have internal quantum efficiency in excess of 350% at a wavelength equal to 250 nm. The devices are stable, have very low dark current at a reverse bias voltage of 1 V and high responsivity. Analysis of the dopant concentration versus junction depth using a sheet resistance technique was done in this work.

PACS Nos.: 85.60Gz, 85.60Bt, 85.60DW