bluuebunny/crossref_metadata_2025_split huggingface dataset:
Human motor compensations for thixotropy‐dependent changes in resting wrist joint position after large joint movements
Authors: Axelson H. W. , Hagbarth K.‐E. 
Published: December 2004

AbstractAim:  Resting tension of relaxed skeletal muscle fibres held at a given length varies with the immediate previous history of length changes and contractions. The primary aim of this study was to explore the motor control consequences of this history‐dependency in healthy subjects.Methods:  Angular position and passive torque were recorded from the intact wrist joint. Integrated surface electromyography (IEMG) was recorded from wrist extensor and flexor muscles.Results:  In relaxed subjects, wrist joint position was displaced towards dorsiflexion after a single high‐amplitude dorsiflexion movement combined with a strong flexor/extensor co‐contraction (dorsiflexion conditioning), whereas after volarflexion conditioning there was a shift towards volarflexion. These after‐effects could be abruptly cancelled by short periods (∼5 s) of rapid flapping hand movements or forceful isometric co‐contractions, findings indicative of muscle thixotropy. The IEMG‐evaluated motor after‐effects were as follows. A slowly subsiding wrist flexor contraction was needed to restore and maintain the original resting wrist position after dorsiflexion conditioning whereas a slowly subsiding extensor contraction was needed for the same goal after volarflexion conditioning. Furthermore, ongoing wrist extensor IEMG activity required to actively hold the wrist in a moderate dorsiflexed position or to resist a constant volar torque at resting position was temporarily reduced after dorsiflexion conditioning and enhanced (not significantly) after volarflexion conditioning.Conclusion:  The results provide evidence that during voluntary maintenance of a desired wrist joint position the motor commands to the position‐holding muscles are unconsciously adjusted to compensate for thixotropy‐dependent variations in the resting tension of the muscles.
Increased tissue survival in experimental skin flaps in mast cell‐deficient rats
Authors: Guo Y. , Törkvist L. , Raud J. , Hedqvist P. 
Published: December 2004

AbstractAim:  The role of mast cells and their principal mediator, histamine, in surgical skin flap survival was investigated using mast cell‐deficient (Ws/Ws); their congenic littermates wild‐type (+/+), and Wistar rats.Methods:  A standardized dorsal skin flap was raised and sutured back into position, and 6 days later the percentage of flap survival was assessed. Moreover, endogenous histamine concentration in the dorsal skin during the surgical preparation was determined using in vivo microdialysis technique together with high performance liquid chromatography‐fluorometry. Accumulation of skin flap myeloperoxidase (MPO) (reflecting leucocyte recruitment) was determined spectrophotometrically.Results:  The experimental skin flaps in genetically mast cell‐deficient rats exhibited increased tissue survival and showed little accumulation of MPO and rather low and stable level of histamine output in comparison with skin flaps in the wild‐type (+/+) littermates or normal Wistar rats. Antihistamine treatment inhibited but did not prevent leucocyte recruitment in the skin flaps post‐surgery in +/+ and Wistar rats.Conclusion:  It is suggested that mast cell derived histamine plays an important role in leucocyte recruitment in skin flaps. However, mast cell‐independent factors should be taken into consideration and needs further investigation as even in mast cell‐deficient animals there was some accumulation of leucocytes and tissue necrosis in the skin flaps post‐surgery.
Effect of the cytoskeletal fixation agent phalloidin on transcapillary albumin transport and interstitial fluid pressure following subdermal prostaglandin E1 administration in the rat
Authors: Brønstad A. , Reed R. K. , Berg A. 
Published: December 2004

AbstractAim:
Lowering of interstitial fluid pressure (Pif) facilitates fluid filtration across the capillary membrane and oedema formation in acute inflammation. The cellular mechanism behind this lowering of Pif involves β1‐integrins mediating contact between dermal cells and the extracellular matrix fibres, and also the cell cytoskeleton as disruption of actin filaments using cytochalasin‐D induced a lowering of Pif and oedema formation. Fixation of actin with phalloidin attenuates oedema formation and abolishes lowering of Pif in anaphylaxis in the rat. The objective of this study was to determine whether phalloidin modifies lowering of Pif and albumin extravasation in rat skin also after prostaglandin E1 (PGE1).Methods:  P
if was measured using micropipettes connected to a servo‐controlled counterpressure system. Microvascular permeability was estimated as the albumin extravasation (Ealb) using radiolabelled human serum albumin.Results:  Subdermal injection of PGE1 (0.85 mg mL−1) lowered Pif from −0.8 ± 0.8 mmHg (SD) in control to −3.5 ± 0.9 mmHg (P < 0.05) within 30 min. Pre‐treatment with phalloidin (500 μg kg−1) before PGE1 resulted in Pif of −1.7 ± 1.0 mmHg (P < 0.05 compared with PGE1). Ealb after subdermal saline was 0.07 ± 0.04 mL g−1 DW and increased to 0.32 ± 0.32 mL g−1 DW with PGE1 (P < 0.05) but was unaffected by pre‐treatment with phalloidin given before PGE1 0.32 ± 0.35 mL g−1 DW (P > 0.05 compared with PGE1 alone).Conclusion:  These results are consistent with the concept that the cytoskeleton actin filaments participate in control of Pif.
Inhibition of nitric oxide synthesis potentiates the colonic permeability increase triggered by luminal bile acids
Authors: Sun Y. , Fihn B.‐M. , Jodal M. , Sjövall H. 
Published: December 2004

AbstractAim:  Experiments were performed in anaesthetized rats to clarify the role of nitric oxide (NO) in the control of colonic permeability.Methods:  Colonic luminal pressure, the transmucosal potential difference (PD) and the clearance of [3H] mannitol and [14C] urea from blood to lumen were measured. NO synthesis was blocked with Nω‐nitro‐l‐arginine (l‐NNA) i.v. and mucosal permeability was increased by deoxycholic acid (DCA, 4 mm). The involvement of histamine in the response was studied by giving the histamine H1 receptor blocker pyrilamine.Results:  In proximal colon, l‐NNA per se increased luminal pressure and PD but had no significant effect on clearance. DCA per se increased luminal pressure, had no significant effect on PD, but increased mannitol and urea clearance and the clearance ratio. l‐NNA and pyrilamine both blocked the luminal pressure effect of DCA but l‐NNA had no significant effect on the clearance response to DCA. In distal colon, l‐NNA per se had no significant effect on pressure and clearance, but increased PD like in proximal colon. DCA had no significant effect on luminal pressure, but markedly reduced PD and increased both clearance and clearance ratio. In this segment, l‐NNA significantly potentiated the clearance response to DCA, and further increased clearance ratio to a value not significantly different from unity (1.00 ± 0.05).Conclusion:  The data suggest that in vivo, moderate concentrations of bile acids increase colonic permeability in rats via a mechanism that is inhibited by NO in distal but not in proximal colon. In distal colon, NO may contribute to the maintenance of epithelial barrier function.
Evidence for intestinal oxidative stress in obstructive jaundice‐induced gut barrier dysfunction in rats
Authors: Assimakopoulos S. F. , Vagianos C. E. , Patsoukis N. , Georgiou C. , Nikolopoulou V. , Scopa C. D. 
Published: December 2004

AbstractAim:  An important factor that promotes bacterial and endotoxin translocation in obstructive jaundice is intestinal injury that causes increased permeability. However, little is known of the submicroscopic biochemical events leading to defects of the intestinal barrier. This study was undertaken to investigate the effect of experimental obstructive jaundice on intestinal lipid peroxidation, protein oxidation and thiol redox state.Methods:  Rats were randomly divided into controls, sham operated and bile duct ligated (BDL). After 10 days, intestinal barrier function was assessed by measuring endotoxin in portal and aortic blood. Tissue samples from the terminal ileum were examined histologically and morphometrically, while other samples were homogenized for the determination of lipid peroxidation, protein oxidation and thiol redox state [reduced glutathione (GSH), oxidized glutathione (GSSG), total non‐protein mixed disulphides (NPSSR), protein thiols (PSH) and protein disulphides (PSSP)].Results:  Obstructive jaundice compromised intestinal barrier function leading to significant portal and systemic endotoxaemia. The intestinal mucosa in jaundiced rats was atrophic with significantly decreased villous density and total mucosal thickness. Determination of biochemical parameters of oxidative stress in the intestine showed increased lipid peroxidation and protein oxidation in BDL‐rats. Thiol redox state revealed the presence of intestinal oxidative stress in jaundiced rats, indicated by a decrease in GSH and increased GSSG, NPSSR and PSSP.Conclusions:  This study shows that experimental obstructive jaundice induces intestinal oxidative stress, which may be a key factor contributing to intestinal injury and leading to endotoxin translocation.
Immune system alteration in response to two consecutive soccer games
Authors: Malm C. , Ekblom Ö. , Ekblom B. 
Published: December 2004

AbstractAim:  Changes in leucocyte and monocyte subpopulations were investigated in 10 elite male soccer players aged 16–19 years. The purpose was to perform a descriptive study of immunological alterations in elite soccer players in response to two consecutive games separated by 20 h. It was hypothesized that in response to two games the players would show signs of short‐term immunosuppression.Methods:  Blood samples were taken before the first soccer game, immediately after the second game and after 6, 24, 48 and 72 h. Cell surface antigens, testosterone and cortisol were investigated.Results:  During the first 6 h after the second game there was a significant increase in number of circulating neutrophils, mature (CD20+ CD5+) B cells and CD4/CD8 ratio. A significant decrease was observed in the number of natural killer (NK) cells, monocytes and adhesion on lymphocytes and monocytes. In a delayed phase, 48 h after the second game the expression of both adhesion and signalling molecules increased on lymphocytes and monocytes. Changes in adhesion and signalling molecules at 48 h correlated negatively to the subjects VO2max, suggesting larger immunological response to similar exercise in subjects with lower aerobic exercise capacity.Conclusion:  In response to competitive soccer exercise some immunological variables are enhanced while others are depressed. Observed changes may serve a purpose in adaptation to exercise by signalling via adhesion.
Effect of knee flexion angle on active joint stiffness
Authors: McHugh M. P. , Hogan D. E. 
Published: December 2004

AbstractAim:  The purpose of this study was to determine if active joint stiffness measured during maximum voluntary knee extension contractions was affected by knee flexion angle.Methods:  Eighteen subjects volunteered (11 male, seven female). A stretch was imposed on isometric knee contractions performed at 30°, 50°, 70°, 90°, and 110° of knee flexion. Active joint stiffness was computed from the increase in torque relative to the change in knee flexion angle for the first 50 ms of the stretch (approximately 1.5°) and corrected for effects of gravitational component due to leg mass and passive tension.Results:  There was a plateau in knee extension torque between 70° and 90° with lower values at all other angles (P < 0.05). Peak active joint stiffness occurred at 70° with lower values (P < 0.05) at all other angles except 50°. Stiffness at 70° (441.1 ± 189.9 Nm rad−1) was 49% higher than at 30° and 45% higher than at 110°.Conclusion:  Active joint stiffness was dependent on knee flexion angle. Peak joint stiffness during maximal contractions occurred at, or prior to, the optimal angle for torque production for all subjects.
Arteriolar dilations induced by contraction of hamster cremaster muscle are dependent on changes in endothelial cell calcium
Authors: Murrant C. L. , Duza T. , Kim M. B. , Cohen K. D. , Sarelius I. H. 
Published: December 2004

AbstractMuscle contraction initiates microvascular arteriolar dilation in regions directly overlapping the active fibres but the cells (vascular smooth muscle cells, endothelial cells) responsible for producing the dilation and the underlying signalling mechanisms are unknown.Aims:  We tested the hypothesis that changes in endothelial cell calcium (Ca2+) are involved in this dilation.Methods:  Four to five muscle fibres lying approximately perpendicular to arterioles (maximum diameter ∼40 μm) were stimulated (4 Hz, 4–20 V, 0.4 ms duration) and observations were made at the site of muscle fibre/arteriole overlap.Results:  Chelation of endothelial cell Ca2+ (with BAPTA) abolished dilations to 120 s of muscle contraction (5.6 ± 1.5 μm in controls vs. 0.51 ± 1.2 μm with BAPTA, n = 6), indicating that changes in endothelial cell Ca2+ are required for the response. To determine the time frame of the Ca2+ signal, we monitored whole endothelial cell Ca2+ (with Fura‐PE3) prior to and following either 120 (n = 13), 30 (n = 9) or 10 (n = 9) s of muscle contraction. In all instances, no changes in Ca2+ were observed despite typical dilator responses.Conclusions:  These data indicate that (i) the initiation of muscle contraction‐induced arteriolar dilations depends on a change in endothelial cell Ca2+, which must be a transient event that takes place early/during stimulation, and (ii) maintenance of the dilation after contraction occurs via mechanisms that are independent of changes in global Ca2+ within the cell.
Regulatory gene expression in skeletal muscle of highly endurance‐trained humans
Authors: Wittwer M. , Billeter R. , Hoppeler H. , Flück M. 
Published: December 2004

AbstractAim and background:  Changes in regulatory and structural gene expression provide the molecular basis for the adaptation of human skeletal muscle to endurance exercise.Hypothesis:  The steady‐state levels of multiple mRNAs mainly involved in regulatory functions differ between highly endurance‐trained and untrained subjects in a muscle heavily recruited during the exercise.Methods:  Biopsies from musculus vastus lateralis of seven untrained (UT) subjects [maximal oxygen consumption (VO2max) = 39 mL kg−1 min−1] and seven trained (T) professional cyclists (VO2max = 72 mL kg−1 min−1) were analysed for the contents of 597 different mRNAs using commercially available cDNA arrays (Clontech no. 7740‐1). Intra‐individual expression profiles were compared by least‐square linear regression analysis. Differences in gene expression between the two groups were tested for statistical significance using L1 regression analysis combined with the sign test on all permutations of scatter plots of log raw values from UT vs. T subjects.Results:  Transcripts for 144 of 597 genes were sufficiently abundant to be analysed quantitatively. The expression profiles of the T group had a better intragroup correlation (R2) than those of the UT group (0.78 vs. 0.65, P < 0.05). An intergroup (T vs. UT) correlation of expression profiles gave an R2 of 0.71. Statistical analysis at a false discovery rate of 5% identified differential expression of nine cell‐regulatory genes between T and UT. The mRNA levels of eight genes, including two DNA repair enzymes, transcription factors, signal transducers, a glycolytic enzyme and a factor involved in steroid hormone metabolism were increased in T vs. UT. Conversely, the mRNA of the tumour suppressor APC was downregulated with endurance training. Selective reverse‐transcriptase polymerase chain reaction experiments confirmed the signal estimates from the array analysis.Conclusions:  The repetitive impact of the complex exercise stimuli in professional cyclists attenuated the interindividual differences in regulatory gene expression in skeletal muscle. Long‐term nuclear reprogramming of regulatory gene expression seems to be characteristic of human musculus vastus lateralis in a highly endurance‐trained steady state.
Effects of fatigue on depolarization‐ and caffeine‐induced contractures of skinned fibres
Authors: Williams J. H. 
Published: December 2004

AbstractAims:  Fatigue has been shown to cause intrinsic alterations in sarcoplasmic reticulum (SR) Ca2+ release.Methods:  In this investigation, frog semitendinosus muscles were stimulated to fatigue, in vitro (80 Hz, 100 ms, 1 train s−1, 5 min). Immediately after stimulation, single fibres were removed and skinned using either chemically or mechanically skinning. Contralateral muscle were treated similarly but were not stimulated.Results:  In fatigued, saponin skinned fibres, contracture responses to low [caffeine] (4–8 mm) were depressed compared with control. However, responses to high concentrations (10–15 mm) were not different between conditions. In the fatigued, mechanically skinned fibres, responses to chloride depolarization were depressed at all [chloride] (20–100 mm) compared with control.Conclusions:  These results suggest that fatigue causes intrinsic alterations in both the SR Ca2+ release channel as well as communication between the transverse‐tubule and the SR.
Clenbuterol treatment affects myosin heavy chain isoforms and MyoD content similarly in intact and regenerated soleus muscles
Authors: Bricout V.‐A. , Serrurier B. D. , Bigard A. X. 
Published: December 2004

AbstractAims:  Pharmacological treatment with the β2‐adrenoceptor agonist clenbuterol is known to induce a slow‐to‐fast fibre type and myosin heavy chain (MHC) isoform transition in intact muscle. This study examined the sensitivity of regenerated soleus muscle to 4 weeks of clenbuterol treatment (2 mg kg−1 day−1).Methods:  Female Wistar rats were divided into two groups: vehicle treated (n = 8) and clenbuterol treated (n = 8). The clenbuterol effects on MHC and MyoD expression were examined in soleus muscles either intact, or previously degenerated by venom of the Notechis scutatus scutatus snake.Results:  Post‐treatment body weights and skeletal muscle weights were not affected by clenbuterol treatment. Muscle protein concentration was higher, and body fat lower in clenbuterol‐treated rats than in vehicle‐treated animals (P < 0.05). Polyacrylamide gel electrophoresis of soleus myofibrillar protein indicated a clenbuterol‐induced decrease in the relative percentage of type I MHC with a concomitant increase in type IIa MHC (31%, P < 0.001). No degeneration effect was observed after 28 days of recovery on the MHC isoform content, and regenerated soleus muscles exhibited the same phenotypical profile as intact soleus muscles, whether or not they were treated with clenbuterol. In intact and in regenerated soleus muscles, MyoD protein levels were significantly increased by clenbuterol treatment (90 and 77%, respectively, P < 0.001).Conclusion:  These results show that regenerated soleus muscles, comprising a homogeneous population of fibres deriving from satellite cells, have a similar response to clenbuterol as intact muscle arising from at least two discrete populations of myotubes; it is suggested that the activity of signalling pathways involved in the effects of clenbuterol on MHC transitions is not related to the developmental history of myofibres.
Medical Practitioners and Their Families as Patients
Authors: Williams Anne Sved 
Published: December 2004

Objective: To explore diagnoses, treatment methods, compliance and outcome in a cohort of medical practitioners and their families seen in a private practice setting to identify characteristics of this group.Methods: A systematic retrospective case-note review was conducted of all medical practitioners, their partners and children seen in a private practice setting over 15 years, documenting mode of referral, diagnosis, attendances, mode of treatment, and outcome.Results: Seventy-seven medical families were identified, including 45 doctors, 21 partners and 11 offspring as the primary patient; 38 of the doctor group were self-referred. Doctors and their families were likely to accept treatment guidelines as recommended and to continue until a joint decision was made to terminate.Conclusions: Doctors presenting themselves for treatment in a private practice are a highly motivated and compliant group, who make significant changes in therapy. They defy directly the usual findings on ‘impaired physicians’ who may be a different group, the latter generally being referred for psychiatric treatment as ‘impaired physicians’ through statutory bodies such as medical boards. With increasing de-stigmatization and increasing education on the benefits of self-care, doctors may be seeking appropriate early intervention.
Consumer and Service Determinants of Completion of a Consumer Self-Rating Outcome Measure
Authors: Trauer Tom 
Published: December 2004

Objective: To study the relative contribution of consumer, clinician and service factors to whether or not consumers completed a self-rating measure in the context of routine outcome measurement. Methods: Four Victorian mental health services commenced routine outcome measurement in their adult services in mid-2000. Clinician-completed measures (Health of the Nation Outcome Scales (HoNOS) and Life Skills Profile (LSP)) and a consumer self-rated measure (Behaviour and Symptom Identification Scale (BASIS)) were entered into specialized software. Analyses were restricted to assessments conducted at review in the community. Results: Wide differences were observed between the four agencies in the rates of completion of the self-rating measure. Overall, consumer characteristics associated with greater likelihood of completion were lower age, non-organic diagnosis, lesser severity as measured by the HoNOS, and lesser disability as measured by the LSP. A more focused analysis showed that agency, lower age, and higher compliance were most reliably associated with completion. Significant proportions of clinicians had no recorded instances of consumer self-rating associated with their assessments. Conclusions: Service and clinician factors appear to be equally important as consumer factors in whether or not a self-rating measure was completed. Information systems designed for outcomes measurement should include indications of whether or not a self-rating was invited, and, if not, why not. The results suggest that consumer self-rating is not yet firmly established in the outcomes measurement culture.
Job Satisfaction and Burnout in Mental Health Services for Older People
Authors: Spear Jonathan , Wood Leanne , Chawla Sudarshan , Devis Antony , Nelson Jim 
Published: December 2004

Objective: The objective of the present paper was to identify factors associated with job satisfaction and burnout among staff working in mental health services for older people. Methods: A postal survey was distributed to staff members from eight mental health services for older people in Western Australia. Staff focus groups identified causes of work stress. Results: The response rate was 33% (116/349). Teamwork, social support and clear roles had a positive effect on job satisfaction. Community staff members had higher job satisfaction than ward staff. Nurses reported higher burnout and lower job satisfaction than other mental health professionals. Staff members working in newer models of service delivery had higher job satisfaction than those working in more traditional models. Conclusion: Surveys and focus groups were an effective means of identifying factors associated with job satisfaction in mental health staff members. Newer models of service delivery with team building and supportive management may improve the workplace for staff.