bluuebunny/crossref_metadata_2025_split huggingface dataset:
Factors triggering upper airway infections in athletes
Authors: König Daniel , Northoff Hinnak , Berg Aloys 
Published: December 2005

Clinical and epidemiological data suggest that strenuous exercise increases the incidence of upper respiratory tract infections (URTI) in athletes. However, little is known if the risk for URT infections is associated with the type of sports performed (e.g., endurance vs. strength exercise, or mixed sports) or whether accompanying lifestyle factors such as dietary behavior, daily stress, and the intake of nutritional supplements or immunostimulants influence the incidence of URT infections. In order to increase our knowledge on such questions, 852 athletes who attended our outpatient department for sports medicine filled out a retrospective questionnaire (1‐year self‐recalled) dealing with the following questions: number of URTI episodes in the last 12 months; number of training days lost due to URTI; type of exercise (endurance/power/mixed type/swimming); training extent; special procedures for regeneration (e.g., physiotherapy); lifestyle and daily stress; dietary behavior; intake of nutritional supplements; and use of immunostimulants. Of the respondents, 72.1% reported one or more URTI episodes in the last 12 months. In a multiple‐regression model, the following variables were positive predictors of an URTI episode: endurance sports [odds ratio, 2.15; CI (95%), 1.51–3.06; p <. 000], daily stress [odds ratio, 1.97; CI (95%), 1.26–3.08; p <. 01], sleep deprivation [odds ratio, 1.69; CI (95%), 1.14–2.5; p <. 01], female gender (odds ratio, 1.5; CI [95%] 1.05–2.13; p <. 05),training extent in hour per week [odds ratio, 1.05; CI (95%), 1.02–1.08; p <. 01), and diet control [odds ratio, 0.6; CI (95%), 0.37–0.82; p <. 01]. The positive predictive value of this model for URTI episodes was 76%. Subgroup analysis revealed that in athletes exhibiting the highest rate of infections, use of immunostimulants reduced the number of training days lost (2 days) due to infections. In conclusion, both sports‐specific items as well as lifestyle variables contribute substantially in explaining the risk for athletes to develop respiratory infections. These findings should be considered in sports‐specific training regimes, particularly in athletes prone to URT infections.
Causative and protective effects of sport injury trait anxiety on injuries in German University sport
Authors: Kleinert Jens 
Published: December 2005

In the present prospective study, we examine relationships between sport injury anxiety, injury history, and the occurrence of injuries. Using the Sport Injury Trait Anxiety Scale (SITAS), 114 male and 92 female sport students were questioned on their concern for sustaining an injury. Furthermore, injury history was assessed using a retrospective‐oriented questionnaire concerning foregoing 1‐year and 5‐year periods of sport activity. After 4 months, subjects were asked about the occurrence of injuries regarding these past 4 months. In respect to injury incidence, we found causative and protective main effects of sport injury trait anxiety. While high injury‐anxious subjects are more likely to sustain a less severe injury (16.3%) than low injury‐anxious subjects (7.6%), this relationship is inverse concerning severe injuries. Subjects with high sport injury anxiety are at lower risk of a severe injury (9.7%) than those with low SITAS scores (22%). To find out interactional effects of injury anxiety and injury history, 4 subgroups were built using a cluster analysis. We found groups with high or low injury trait anxiety and high or low injury experiences, respectively. The group with high injury experiences and simultaneously low injury anxiety shows significantly more severe injuries (28%) than the other groups. Furthermore, the group with high injury experiences and simultaneously high injury anxiety sustains less severe injuries significantly more frequently (22%) than the other groups. These results are discussed as a function of an inadequate perception and an unrealistic estimation of their own physical and technical competencies and situational possibilities, especially in the case of high injury history.
The effect of rest periods on energy system contribution during interval swimming
Authors: Shimoyama Yoshimitsu , Tomikawa Masamitsu , Nomura Takeo 
Published: December 2005

The purpose of this study was to investigate the effect of rest periods on energy system contribution during interval swimming and whether the energy system contribution varied depending on the swimmer's specialty, such as swimmers who specialize in the 100 m or 200 m. Seven highly‐trained male varsity swimmers performed three different tests: a 10‐min continuous test (CON), 10 × 1‐min interval test with rest periods of 20 s (INT20) and 10 × 1‐min interval test with rest periods of 30 s (INT30). Swimming velocity during all tests was set to maintain a blood lactate of 4 mM determined by progressive swimming. The relative aerobic and anaerobic energy system contribution was evaluated from accumulated oxygen uptake and oxygen deficit. Aerobic energy system contribution in CON, INT20, and INT30 was 93.3 ±1.1, 81.0 ±10.4, and 67.4 ±8.5%, and anaerobic contribution was 6.7 ±1.1, 19.0 ±10.4, and 32.6 ±8.5%, respectively. There were significant differences (p
Plasma prolactin concentration increases during hyperoxia: A new hypothesis for its causes
Authors: Vega Sandra , Strüder Heiko , Abel Thomas , Mester Joachim , Hollmann Wildor 
Published: December 2005

The acute responses of plasma prolactin (PRL) concentration to inspiration of 80 Vol% oxygen over 45 min at rest were analyzed in 8 male subjects. After 15, 30, and 45 min of oxygen inhalation, a significant increase (p <. 01) of arterial partial pressure of carbon dioxide (p CO2) in cerebrospinal fluid (CSF) due to well‐established Haldane effect induced by hyperoxia lead to decreased (p 2 at these time points. Plasma PRL concentration was significantly increased (p
CHO‐induced blunting of cortisol response to weightlifting exercise in resistance‐trained older men
Authors: Tarpenning Kyle , Hawkins Steven , Wiswell Robert 
Published: December 2005

With weightlifting exercise, the attenuation of the cortisol response is a major factor by which an increase in muscle mass occurs. A reduction in the exercise‐induced cortisol response has been observed in younger but not older men, suggesting that under normal circumstances older men may lack the mechanism(s) to down‐regulate cortisol activity. The purpose of this study was to determine if CHO consumption during a weightlifting exercise bout could modify the cortisol response to exercise. Five resistance‐trained older men (62.8 ± 1.5 y) completed (on 2 occasions) a 9‐station weightlifting protocol (3 sets, 10 repetitions, 75% of 1RM). One session included the ingestion of a placebo beverage, and the other, a CHO solution. Blood samples were collected prior to, during, and after the exercise bout. With the placebo, plasma glucose levels remained unchanged, while plasma cortisol levels were significantly elevated (from 284 ± 49.7 nmol/L to 474 ± 130 nmol/L). In contrast, CHO consumption resulted in significantly higher plasma glucose levels (from 5.55 ±. 48 to 7.63 ± 0.53 mmol) and a blunted cortisol response. These findings indi‐cate that the stimulatory effect of exercise on cortisol secretion can be overcome by CHO administration.
Performance profile and health assessment of elite quad rugby players
Authors: Abel Thomas , Peters Christiane , Platen Petra 
Published: December 2005

Objective:Since 1992, the sport of quad rugby has gained increasing popularity in Germany. This has led to the desire to record reference parameters of func‐tional efficiency. Investigation: Thirteen male, quadriplegically handicapped quad rugby players from the German league took part in the investigation. The maximum functional efficiency (W) and speed (m/s) with associated heart rate and lactate values were 45.4 ± 6.9 W, 124.0 ± 19.0 bpm, 4.07 ± 1.09 mmol/L using the arm crank. On the frictionless roller, the values were 2.17 ± 0.48m/s, 133.0 ± 19.1 bpm, 3.91 ± 1.42 mmol/L. In the field test, the values were 3.01 ± 0.64m/s, 142.1 ± 27.5 bpm, 5.63 ± 3.05 mmol/L. Comparison of the heart rate and lactate parameters at the arm crank and on the frictionless roller under maximum load revealed significantly higher heart rate (p =. 037) with no sig‐nificant differences in lactate (p =. 660; n = 13).Conclusion:Health assess‐ments in quad rugby are possible using arm crank and frictionless roller ergometry. The essential requirement for being encouraged to make use of performance assessments is that they are carried out as specific as possible with respect to the type of sport involved.
Effects of a resistance training on pulmonary function and performance measurements in patients with chronic obstructive pulmonary disease
Authors: Wright Peter , Heck Hermann , Langenkamp Heiner 
Published: December 2005

Background: Exercise therapy with its manifold effects should be part of a modern and multi‐modular treatment of chronic obstructive pulmonary disease (COPD). In literature, mainly endurance training is recommended. Because of the specific symptoms (e.g., muscle atrophy, dyspnea, low testosterone levels) and the de‐conditioning of these patients, resistance training might meet the demands of a COPD‐exercise‐therapy rather than endurance training. The aim of this research project was to evaluate the efficiency of strength training on various COPD‐relevant parameters. Methods: Twenty‐eight patients with moderate to severe COPD (12 male, 16 female) were randomized and divided into a treatment and a control group. The patients in the treatment group underwent a hypertrophic maximal strength training for 12 weeks, initially twice, then 3 times a week for 60 to 120 min. Results: The FEV1 performance (forced expiratory volume in 1 s) showed a significant increase (p=.01) of 5.3%. Whereas in the daily peak‐flow measurement, there was no significant change in both groups, a trend towards improvement of this parameter could be found in the treatment group by 20 L. The performance on the ergo cycle showed a significant improvement (p <. 001) of the treatment group of 18.7% (21.9 W). The results of the St. George's Respiratory Questionnaire also showed a significantimprovement (p <. 05) of the health‐related quality of life (HRQL) in the treatment group. A change of the HRQL in the control group was not found. Conclusions: These data support the hypotheses that a short‐term, high‐intensity strength training program is suitable to improve pulmonary function and performance measurements of patients with moderate to severe COPD. These changes lead to an improved performance of daily activities and general wellbeing. The conclusion can be drawn that hypertrophic maximal strength training is preferable for a COPD‐specific exercise therapy and offers new treatment perspectives.
Treatment of Nonalcoholic Steatohepatitis: The Effects of Regular Exercise
Authors: Achten Juul , Sutedja Dede , Johnson Jill , Jeukendrup Asker , Jones David , Elias Elwyn 
Published: December 2005

The aim of the present study was to investigate the effects of supervised regular aerobic exercise on clinical, biochemical, and metabolic features in patients with NASH. Nine male patients diagnosed with NASH were randomly divided into an exercise group (E) and a non‐exercise group (NE). Patients in the E group followed a 12‐week supervised aerobic exercise program. All patients were reviewed at 6 and 12 weeks for symptomatology, anthropometry, liver panels, and lipid profiles. In addition, the fitness level of the patients was measured every 6 weeks during a graded exercise test to exhaustion on a cycleergometer. Patients in the E group who performed, on average, 45 min of moderate intensity exercise 4 times a week significantly increased their maximal work rate (p<. 05), while no change was seen in the NE group. A trend towards decreased respiratory exchange ratios and lactate concentrations during exercise in the E group suggested a greater reliance on fat metabolism. After 12 weeks, body and fat mass and waist:hip ratio changed significantly in the E group, while no changes were seen in the NE group. Serum ALT activity decreased significantly after 12 weeks in the E group (88 ± 6 vs. 53 ± 10 U · L−1), while values remained the same in the NE group. The data of the present study suggest that regular exercise can be a valuable tool in the treatment of NASH.
Identification of surface‐exposed components of MOMP of Chlamydia trachomatis serovar F
Authors: Wang Yan , Berg Eric A. , Feng Xiaogeng , Shen Li , Smith Temple , Costello Catherine E. , Zhang You‐Xun 
Published: December 2005

AbstractThe identification of surface‐exposed components of the major outer membrane protein (MOMP) of Chlamydia is critical for modeling its three‐dimensional structure, as well as for understanding the role of MOMP in the pathogenesis of Chlamydia‐related diseases. MOMP contains four variable domains (VDs). In this study, VDII and VDIV of Chlamydia trachomatis serovar F were proven to be surface‐located by immuno‐dot blot assay using monoclonal antibodies (MAbs). Two proteases, trypsin and endoproteinase Glu‐C, were applied to digest the intact elementary body of serovar F under native conditions to reveal the surface‐located amino acids. The resulting peptides were separated by SDS‐PAGE and probed with MAbs against these VDs. N‐terminal amino acid sequencing revealed: (1) The Glu‐C cleavage sites were located within VDI (at Glu61) and VDIII (at Glu225); (2) the trypsin cleavage sites were found at Lys79 in VDI and at Lys224 in VDIII. The tryptic peptides were then isolated by HPLC and analyzed with a matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometer and a quadrupole‐orthogonal‐TOF mass spectrometer coupled with a capillary liquid chromatograph. Masses and fragmentation patterns that correlated to the peptides cleaved from VDI and VDIII regions, and C‐terminal peptides Ser333–Arg358 and Ser333–Lys350 were observed. This result demonstrated that these regions are surface‐exposed. Data derived from comparison of nonreduced outer membrane complex proteolytic fragments with their reduced fractions revealed that Cys26, 29, 33, 116, 208, and 337 were involved in disulfide bonds, and Cys26 and 337, and 116 and 208 were paired. Based on these data, a new two‐dimensional model is proposed.
Human soluble epoxide hydrolase: Structural basis of inhibition by 4‐(3‐cyclohexylureido)‐carboxylic acids
Authors: Gomez German A. , Morisseau Christophe , Hammock Bruce D. , Christianson David W. 
Published: December 2005

AbstractX‐ray crystal structures of human soluble epoxide hydrolase (sEH) complexed with four different dialkylurea inhibitors bearing pendant carboxylate “tails” of varying length have been determined at 2.3–3.0 Å resolution. Similarities among inhibitor binding modes reinforce the proposed roles of Y381 and/or Y465 as general acids that protonate the epoxide ring of the substrate in concert with nucleophilic attack of D333 at the electrophilic epoxide carbon. Additionally, the binding of these inhibitors allows us to model the binding mode of the endogenous substrate 14,15‐epoxyeicosatrienoic acid. Contrasts among inhibitor binding modes include opposite orientations of inhibitor binding in the active‐site hydrophobic tunnel. Alternative binding orientations observed for this series of inhibitors to human sEH, as well as the binding of certain dialkylurea inhibitors to human sEH and murine sEH, complicate the structure‐based design of human sEH inhibitors with potential pharmaceutical applications in the treatment of hypertension. Thus, with regard to the optimization of inhibitor designs targeting human sEH, it is critical that human sEH and not murine sEH be utilized for inhibitor screening, and it is critical that structures of human sEH‐inhibitor complexes be determined to verify inhibitor binding orientations that correlate with measured affinities.
Subtle but variable conformational rearrangements in the replication cycle of Sulfolobus solfataricus P2 DNA polymerase IV (Dpo4) may accommodate lesion bypass
Authors: Wang Yanli , Arora Karunesh , Schlick Tamar 
Published: December 2005

AbstractThe possible conformational changes of DNA polymerase IV (Dpo4) before and after the nucleotidyl‐transfer reaction are investigated at the atomic level by dynamics simulations to gain insight into the mechanism of low‐fidelity polymerases and identify slow and possibly critical steps. The absence of significant conformational changes in Dpo4 before chemistry when the incoming nucleotide is removed supports the notion that the “induced‐fit” mechanism employed to interpret fidelity in some replicative and repair DNA polymerases does not exist in Dpo4. However, significant correlated movements in the little finger and finger domains, as well as DNA sliding and subtle catalytic‐residue rearrangements, occur after the chemical reaction when both active‐site metal ions are released. Subsequently, Dpo4's little finger grips the DNA through two arginine residues and pushes it forward. These metal ion correlated movements may define subtle, and possibly characteristic, conformational adjustments that operate in some Y‐family polymerase members in lieu of the prominent subdomain motions required for catalytic cycling in other DNA polymerases like polymerase β. Such subtle changes do not easily provide a tight fit for correct incoming substrates as in higher‐fidelity polymerases, but introduce in low‐fidelity polymerases different fidelity checks as well as the variable conformational‐mobility potential required to bypass different lesions.
Solubility engineering and crystallization of human apolipoprotein D
Authors: Nasreen Amber , Vogt Martin , Kim Hyun Jin , Eichinger Andreas , Skerra Arne 
Published: December 2005

AbstractHuman apolipoprotein D (ApoD) is a physiologically important member of the lipocalin protein family that was discovered as a peripheral subunit of the high‐density lipoprotein (HDL) but is also abundant in other body fluids and organs, including neuronal tissue. Although it has been possible to produce functional ApoD in the periplasm of Escherichia coli and to demonstrate its ligand‐binding activity for progesterone and arachidonic acid, the recombinant protein suffers from a pronounced tendency to aggregate and to adsorb to vessel surfaces as well as chromatography matrices, thus hampering further structural investigation. Here, we describe a systematic mutagenesis study directed at presumably exposed hydrophobic side chains of the unglycosylated recombinant protein. As a result, one ApoD mutant with just three new amino acid substitutions—W99H, I118S, and L120S—was identified, which exhibits the following features: (1) improved yield upon periplasmic biosynthesis in E. coli, (2) elution as a monomeric protein from a gel permeation chromatography column, and (3) unchanged binding activity for its physiological ligands. In addition, the engineered ApoD was successfully crystallized (space group I4 with unit cell parameters a = 75.1 Å, b = 75.1 Å, c = 166.0 Å, α = β = γ = 90°), thus demonstrating its conformationally homogeneous behavior and providing a basis for the future X‐ray structural analysis of this functionally still puzzling protein.
Simulation of pH‐dependent edge strand rearrangement in human β‐2 microglobulin
Authors: Park Sheldon , Saven Jeffery G. 
Published: December 2005

AbstractAmyloid fibrils formed from unrelated proteins often share morphological similarities, suggesting common biophysicalmechanisms for amyloidogenesis. Biochemical studies of human β‐2 microglobulin (β2M) have shown that its transition from a water‐soluble protein to insoluble aggregates can be triggered by low pH. Additionally, biophysical measurements of β2M using NMR have identified residues of the protein that participate in the formation of amyloid fibrils. The crystal structure of monomeric human β2M determined at pH 5.7 shows that one of its edge β‐strands (strand D) adopts a conformation that differs from other structures of the same protein obtained at higher pH. This alternate β‐strand arrangement lacks a β‐bulge, which may facilitate protein aggregation through intermolecular β‐sheet association. To explore whether the pH change may yield the observed conformational difference, molecular dynamics simulations of β2M were performed. The effects of pH were modeled by specifying the protonation states of Asp, Glu, and His, as well as the C terminus of the main chain. The bulged conformation of strand D is preferred at medium pH (pH 5–7), whereas at low pH (pH < 4) the straight conformation is observed. Therefore, low pH may stabilize the straight conformation of edge strand D and thus increase the amyloidogenicity of β2M.
Structural interpretation of mutations and SNPs using STRAP‐NT
Authors: Gille Christoph 
Published: December 2005

AbstractVisualization of residue positions in protein alignments and mapping onto suitable structural models is an important first step in the interpretation of mutations or polymorphisms in terms of protein function, interaction, and thermodynamic stability. Selecting and highlighting large numbers of residue positions in a protein structure can be time‐consuming and tedious with currently available software. Previously, a series of tasks and analyses had to be performed one‐by‐one to map mutations onto 3D protein structures; STRAP‐NT is an extension of STRAP that automates these tasks so that users can quickly and conveniently map mutations onto 3D protein structures. When the structure of the protein of interest is not yet available, a related protein can frequently be found in the structure databases. In this case the alignment of both proteins becomes the crucial part of the analysis. Therefore we embedded these program modules into the Java‐based multiple sequence alignment program STRAP‐NT. STRAP‐NT can simultaneously map an arbitrary number of mutations denoted using either the nucleotide or amino acid sequence. When the designations of the mutations refer to genomic sites, STRAP‐NT translates them into the corresponding amino acid positions, taking intron–exon boundaries into account. STRAP‐NT tightly integrates a number of current protein structure viewers (currently PYMOL, RASMOL, JMOL, and VMD) with which mutations and polymorphisms can be directly displayed on the 3D protein structure model. STRAP‐NT is available at the PDB site and at http://www.charite.de/bioinf/strap/ or http://strapjava.de.