Stress responses to short-term intensified and reduced training in competitive weightlifters.

We sought to identify and evaluate the tolerance to, and consequences of, short-term variations in training load in competitive weightlifters. Seven international-level lifters performed 1 week of initial training followed by 2 weeks of intensified (INT: +100%, 36.5 ± 11.3 × 10(3) kg/week) and 1 week of subsequently reduced (RED: -25%) training within their annual program. After INT, but not RED, 90 min of weightlifting increased mRNA levels of chemokine (C-C motif) ligand 4 (CCL4), chemokine (C-X-C motif) receptor 4 (CXCR4) and cellular stress-associated DNA-damage-inducible transcript 4 (DDIT4) in peripheral blood mononuclear cells by 40-240%. Resting- and weightlifting-induced changes in plasma protein carbonyls, indicative of oxidative stress, but not pro-inflammatory CCL4 concentrations differed between INT and RED. Symptoms of stress (Daily Analysis of Life Demands of Athletes questionnaire) were reported as worse than normal more frequently during INT and RED than initial training. Global (negative) mood state increased during INT and declined during RED. Maximal snatch (-4.3 ± 3.7%) and vertical jump (-7.2 ± 6.5%), but not clean and jerk, were reduced after INT and restored after RED. Chemokine signaling may thus be part of the stress response to intense weightlifting and short-term reductions in training load support recovery from periodic INT training in weightlifters.

Foxn4--a new member of the forkhead gene family is expressed in the retina.

We report the cloning and expression of a novel murine forkhead/winged helix family member--Foxn4--that is expressed during neural development in the retina, the ventral hindbrain and spinal cord and dorsal midbrain. Retinal Foxn4 expression is associated with the zone of proliferating progenitor cells. In the mouse mutant ocular retardation (or(J)), Foxn4 expression in the retina is significantly reduced and terminates prematurely.

Undernutrition regulates the expression of a novel splice variant of myostatin and insulin-like growth factor 1 in ovine skeletal muscle.

Undernutrition suppresses the growth of skeletal muscles and alters the expression of insulin-like growth factor 1 (IGF1), a key mitogen, and myostatin, a potent inhibitor of myogenesis. These changes can explain, at least in part, the reduced growth of skeletal muscles in underfed lambs. We have recently identified a myostatin splice variant (MSV) that binds to and antagonizes the canonical signaling of myostatin. In the present study, we hypothesized that the expression of MSV would be reduced in conjunction with myostatin and IGF1 in response to underfeeding in skeletal muscles of sheep. Young growing ewes were fed either ad libitum or an energy-restricted diet (30% of maintenance requirements) for 28 d. This regime of underfeeding resulted in a 24% reduction in body mass (P < 0.001) and a 36% reduction in the mass of the semitendinosus muscles relative to controls (P < 0.001) by day 28. The concentrations of MSV and IGF1 messenger RNA (mRNA) were reduced (both P < 0.001), but myostatin mRNA was not altered in semitendinosus muscles. Unlike the reduced expression of mRNA, the abundance of MSV protein was increased (P < 0.05) and there was no change in the abundance of myostatin protein. Our results suggest that undernutrition for 28 d decreases the signaling of myostatin by increasing the abundance of MSV protein. Although this action may reduce the growth inhibitory activity of myostatin, it cannot prevent the loss of growth of skeletal muscles during undernutrition.

Expression of Drosophila omb-related T-box genes in the developing human and mouse neural retina.

PURPOSE: To examine the role of Drosophila optomotor blind (omb)-related T-box genes in development of human and mouse retina. METHODS: Mouse Tbx2, Tbx3, and Tbx5 and human TBX2 cDNAs were isolated from retinal cDNA libraries by hybridization to the Drosophila omb gene. Gene expression patterns in developing retina were analyzed by in situ hybridization. RESULTS: TBX2/Tbx2, TBX3/Tbx3, and TBX5/Tbx5 were expressed asymmetrically across the embryonic neural retina with highest levels of mRNA within dorsal and peripheral retina. The dorsoventral gradient of TBX2 expression disappeared before the ganglion cell layer (GCL) formed. Its expression then became restricted to the inner neuroblastic retina and later to the GCL and inner nuclear layer (INL). The dorsal expression domains of TBX5/Tbx5 and TBX3/Tbx3 were maintained during formation of the GCL. As the retina matured, TBX3/Tbx3 expression was restricted to the INL, and TBX5/Tbx5 was expressed within the GCL. CONCLUSIONS: The expression pattern of TBX2, TBX3, and TBX5 within the developing retina supports the idea that the encoded transcription factors play a role in providing positional information important for topographic mapping and in differentiation of distinct cell types across the laminar axis of the retina.

Influence of female reproductive anatomy on the outcome of sperm competition in Drosophila melanogaster.

Females as well as males can influence the outcome of sperm competition, and may do so through the anatomy of their reproductive tracts. Female Drosophila melanogaster store sperm in two morphologically distinct organs: a single seminal receptacle and, normally, two spermathecae. These organs have different temporal roles in sperm storage. To examine the association between sperm storage organ morphology and sperm competition, we used a mutant type of female with three spermathecae. Although the common measure of sperm competition, P(2), did not differ between females with two and three spermathecae, the pattern of sperm use over time indicated that female morphology did affect male reproductive success. The rate of offspring production by females with three spermathecae rose and fell more rapidly than by females with two spermathecae. If females remate or die before using up second male sperm, then second male reproductive success will be higher when they mate with females with three spermathecae. The results indicate that temporal patterns of sperm use as well as P(2) should be taken into account when measuring the outcome of sperm competition.

Interactions of mating, egg production and death rates in females of the Mediterranean fruit fly, Ceratitis capitata.

Costs of reproduction include costs of producing eggs and of mating itself. In the present study, we made an experimental investigation of costs of reproduction in the Mediterranean fruit fly (medfly, Ceratitis capitata). We demonstrated that virgins live longer than non-virgin females. However, in strong contrast to most findings within the Diptera, non-virginity had no detectable effect on egg production. Therefore the increased longevity of the virgin females cannot be attributed to an increase in egg production in non-virgin females, and instead indicates a cost of mating. A comparison of the life spans of normal females and those sterilized by low doses of X-irradiation, revealed an additional cost of egg production. There were no significant differences in remating levels between females that did and did not lay eggs, showing that the cost of producing eggs is independent of mating frequency. Medfly females therefore suffer a decrease in survival as a result of egg production and of mating, and these costs are independent of one another. To put our results into context, we reviewed the existing literature on the effects of mating on longevity, egg production and sexual receptivity for 64 species of Diptera, and examined the pattern of mating effects that emerged.

Prolonged underfeeding of sheep increases myostatin and myogenic regulatory factor Myf-5 in skeletal muscle while IGF-I and myogenin are repressed.

The IGF axis is nutritionally sensitive in vivo and IGFs stimulate myoblast proliferation and differentiation in vitro, while myostatin inhibits these processes in vitro. We hypothesised that underfeeding would reversibly inhibit the myogenic activity of satellite cells in vivo together with decreased IGF-I and increased myostatin in muscle. Satellite cell activity was measured indirectly from the expression of proliferating cell nuclear antigen (PCNA) and the myogenic regulatory factors (MRFs), MyoD, Myf-5 and myogenin. Young sheep were underfed (30% of maintenance) and some killed after 1, 4, 12, 17, 21 and 22 weeks. Remaining underfed animals were then re-fed a control ration of pellets and killed after 2 days, and 1, 6 and 30 weeks. Expression of PCNA and MRFs decreased during the first week of underfeeding. This coincided with reduced IGF-I and myostatin mRNA, and processed myostatin. Subsequently, Myf-5, MyoD, myostatin mRNA and processed myostatin increased, suggesting that satellite cells may have become progressively quiescent. Long-term underfeeding caused muscle necrosis in some animals and IGF-I and MRF expression was increased in these, indicating the activation of satellite cells for muscle repair. Re-feeding initiated rapid muscle growth and increased expression of PCNA, IGF-I and the MRFs concurrently with decreased myostatin proteins. In conclusion, these data indicate that IGF-I and myostatin may work in a coordinated manner to regulate the proliferation, differentiation and quiescence of satellite cells in vivo.

Exercise-enhanced satellite cell proliferation and new myonuclear accretion in rat skeletal muscle.

The effects of increased functional loading on early cellular regenerative events after exercise-induced injury in adult skeletal muscle were examined with the use of in vivo labeling of replicating myofiber nuclei and immunocyto- and histochemical techniques. Satellite cell proliferation in the soleus (Sol) of nonexercised rats (0.4 +/- 0.2% of fibers) was unchanged after an initial bout of declined treadmill exercise but was elevated after two (1.0 +/- 0.2%, P < or = 0.01), but not four or seven, daily bouts of the same task. Myonuclei produced over the 7-day period comprised 0.9-1.9% of myonuclei in isolated fibers of Sol, tibialis anterior, and vastus intermedius of nonexercised rats. The accretion of new myonuclei was enhanced (P < or = 0.05) in Sol and vastus intermedius by the initial exercise followed by normal activity (to 3.1-3.4% of myonuclei) and more so by continued daily exercise (4.2-5.3%). Observed coincident with a lower incidence of histological fiber injury and unchanged fiber diameter and myonuclei per millimeter, the greater new myonuclear accretion induced by continued muscle loading may contribute to an enhanced fiber repair and regeneration after exercise-induced injury.

The danger of an ultra-early computed tomographic scan in a patient with an evolving acute epidural hematoma.

A case of an acute traumatic epidural hematoma that developed after an ultra-early computed tomographic scan of the head is discussed. Serial neurological examinations in patients with head injuries are recommended.

Applied physiology of water polo.

Water polo has been played for over a century. While the rules of the game have evolved considerably over this time, the sport has consistently remained, physiologically, a highly demanding activity. Much attention has been paid to the technical and strategic elements of the game; however, despite the potential for improvements in athletic performance and the maintenance of athletes' health, there are few published studies (particularly in English) on the physical and physiological demands and adaptations to water polo training and competition. Game analyses have demonstrated that water polo is an 'intermittent' sport comprised of intense bursts of activity of <15 seconds duration with intervening, lower intensity intervals averaging <20 seconds duration. Physiological measurements obtained during game play indicate a cumulative effect of the repeated sequences of activities and suggest there is a high metabolic demand on the athletes. The multiple individual skills and movements required for playing water polo also place considerable demands on the neuromuscular system. Observations of the frequency and duration of the different activities, and of the physiological responses to participating in a water polo match, are initial sources of information for designing training programmes specific to the game and to the different playing positions. The physical and physiological attributes of elite water polo players offer some insight into the minimum requirements for participation and the adaptations that result from training and competition. Further systematic documentation and experimentation are required to facilitate the design and specification of individual training programmes and to better understand the long term effects of water polo on athletes' health.

Outcome of aggressive removal of cavernous sinus meningiomas.

Despite recent advances in surgery of the cavernous sinus, meningiomas in that area offer a formidable challenge. The rationale for aggressive surgical removal of cavernous sinus meningiomas is based on the presumption that the extent of removal is inversely related to the rate of recurrence. Over the past 10 years, 41 patients with histologically benign meningiomas involving the cavernous sinus underwent aggressive surgery. Total removal, as confirmed by intraoperative inspection and postoperative radiological studies, was achieved in 31 patients (76%). Twelve patients have been followed for more than 5 years; 10 underwent total tumor removal and only one of these experienced recurrence (5 years after surgery). The other two patients underwent subtotal removal and had symptomatic and radiological evidence of regrowth 3 and 4 years after surgery. Pre-existing cranial nerve deficits improved in only 14% of the patients, remained unchanged in 80%, and worsened permanently in 6%. Seven patients experienced a total of 10 new cranial nerve deficits, four of which involved the nerves subserving ocular motor function. Extraocular muscle function did not worsen in the 25 patients with a seeing eye ipsilateral to the tumor, and no instance of visual worsening occurred. Two patients died 4 months after surgery, one from severe delayed vasospasm and hypothalamic infarction and the other because of a myocardial infarction. Another patient died from a pulmonary embolus on the 9th postoperative day. There were three instances of cerebral ischemia; one was transient, lasting less than 24 hours, while two were related to injury of the middle cerebral artery and resulted in residual hemiplegia. Other complications included three cases of nonfatal pulmonary emboli, two cerebrospinal fluid leaks, and one instance each of exposure keratitis, acute hypothyroidism, and cerebral edema.

Penalty shot importance, success and game context in international water polo.

To establish the incidence, timing and quantitative importance of penalty shots in water polo and to test whether or not penalty shot success would vary with the context (closeness, quarter, criticality) of the game, official records from six major international tournaments (n= 296 games) were analysed. Across all tournaments, penalties (n= 206) were awarded (1-3 per game) in 51% of games with no difference in frequency between game quarters. Penalty goals (n= 165) comprised only 3.7% of all goals scored, whereas the outcome of penalties (goal/no goal) within each game affected the final outcome (win/loss/tie) of 20% of games. The success rate of penalty shots (80.1%) was not significantly different between games classed as either close or non-close, by a mathematical expression of the running average goal difference up until the time of the penalty, and by the absolute difference of the score at the time of the penalty. Nor was this success rate significantly different between game quarters (72.7, 83.0, 81.5, and 81.8%), or between games classified by their criticality to final tournament placing (80.0, 79.5, and 80.6%, from highest to lowest). Thus, during international water polo, penalties contribute only modestly to game outcome, and penalty shot success is not significantly related to the closeness, quarter, or criticality of the game being played.

The effect of pain after total knee arthroplasty on the contralateral, nonreplaced knee.

BACKGROUND: Osteoarthritis is associated with a strong biomechanical component. Persistent pain in the index knee after total knee arthroplasty could lead to pain in the contralateral knee. The purpose of the present study was to examine whether a change in the natural history of pain in the contralateral knee was related to postoperative pain in the index knee. METHODS: Seven hundred and seventy-two patients undergoing primary unilateral total knee arthroplasty with use of the Kinemax prosthesis for the treatment of osteoarthritis comprised the cohort (Kinemax Outcomes Study cohort). Patients were assessed preoperatively and were followed for twenty-four months after surgery with use of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). We collected separate WOMAC pain scores for the index knee and the contralateral knee. Our primary outcome measure was the WOMAC pain score (rescaled to 100, with 100 being the best score) for the contralateral knee at three, twelve, and twenty-four months. We examined whether within-subject changes in the WOMAC pain score for the contralateral knee were predicted by the WOMAC pain score for the index knee at three months with use of linear regression and multilevel models after adjustment for sex, age, country, body mass index, income, and mental well-being. RESULTS: Improvement in terms of pain was observed in both the index and contralateral knees between baseline and three months. Subsequently, there was a modest deterioration of 3.5 units per year (standard deviation, 9.8 units per year) in the contralateral knee (p < 0.001), which was not predicted by pain in the index knee shortly after surgery (p > 0.6). CONCLUSIONS: Pain in the index knee at three months after total knee arthroplasty did not appear to predict a symptomatic increase in pain in the contralateral knee over two years of follow-up in our cohort. The contralateral knee did not require any additional clinical surveillance over and above the patients' reports on their symptoms.

Voluntary resistance wheel exercise during post-natal growth in rats enhances skeletal muscle satellite cell and myonuclear content at adulthood.

AIM: To determine whether voluntary free wheel (FW) or resistance wheel (RW) exercise or reduced muscle activity would influence maturational increases in muscle mass and the number of satellite cells (SCs) and myonuclei (MN) accrued by adulthood. METHODS: Hind limb muscles of male rats housed with, or without, FWs from 4 to 5, 7 or 10 weeks of age, and rats housed with RWs from 4 to 10 week of age, were evaluated. To assess the effect of reduced muscle activity, gastrocnemius muscles of 4-week-old rats were injected with botulinum toxin (Btx) and collected at 7 weeks of age. Muscle fibre size and the frequency of Pax7-positive SCs and MN were determined in 7- and 10-week-old muscles via immunohistochemical methods. RESULTS: Free wheel exercise enhanced muscle growth and the frequency of SCs in the medial gastrocnemius (MG) (threefold) and vastus lateralis (VL) (twofold) of rats at 10 week of age. Resistance wheel exercise increased the number of SCs and MN (22-30%), with more muscle fibre nuclei being associated with larger fibre size, in the soleus, MG and VL muscles. Btx impaired the normal increases in muscle fibre size and the accrual of MN but not SCs. CONCLUSION: A greater volume of exercise during maturational growth was important for enhancing SC numbers, whereas their conversion to MN required higher-intensity exercise. The enhanced muscle fibre nuclear populations may influence the capacity of the muscle to adapt to exercise, injury or disuse in later adulthood.

Return to work following knee arthroplasty.

A retrospective study of a consecutive cohort of 109 patients, under the age of 60, who had either a Patellofemoral replacement (PFR), Unicompartmental replacement (UKR) or a Total knee replacement (TKR). They were operated on by two senior surgeons between 2002 and 2006 at the Avon Orthopaedic Centre in Bristol. The aim of this study was to look at the effect of knee replacement on the employment status of this group of patients. Data were collected from patient's hospital records and a questionnaire regarding occupational status was sent postoperatively to the patients. Statistical analysis showed that our groups were similar which meant that further comparison between them was valid. Eighty-two percent of the patients who were working prior to surgery and who had either a TKR or UKR were able to return to work postoperatively. Only 54% of those who had a PFR were able to return to work and this was statistically significant when compared with patients in the other two groups p=0.047. The median time for return to work postoperatively for the study population was 12 weeks. Those in the PFR group took significantly longer to do so (20 weeks) compared to those who had either a UKR (11 weeks) or TKR (12 weeks) p=0.01. Patient's subjective opinion as to their ability to work following knee arthroplasty was worse in the PFR group p=0.049. This is the first study to compare employment status following Patellofemoral, Unicompartmental knee and Total Knee Replacement. TKR and UKR are effective in returning patients under 60 years old to active employment and this is typically 3 months following surgery. Patients who had a PFR did not experience the same benefits in terms of numbers returning to work, time to do so and their subjective opinion as to their ability to cope with normal duties.

Ergometer sprint performance and recovery with variations in training load in elite rowers.

The effects of 3 weeks of a 30% increase in training volume, followed by 1 week of reduced volume (approximately 75%) training, on ergometer sprint performance and physiological recovery responses, were determined from an initial group of ten male and eight female elite rowers. No significant (p > 0.05) differences in mean (+/- SD) 500 m time trial performances were found when comparing 500 m times prior to, and after 3 weeks of overload training (89.4 +/- 7.3 s vs. 88.1 +/- 7.3 s), or from the end of the overload training to after the regeneration week (88.6 +/- 6.8s), or over the full 4-week overload-regeneration cycle. Peak and recovery heart rate responses to the test did not differ with training. However, recovery blood lactate concentrations increased, and blood ammonia decreased, after the third and fourth weeks of training. The results indicate that 3 weeks of overload training did not compromise ergometer sprint performance, but altered the metabolic responses during passive recovery. A subsequent 1-week period of 25% reduced volume training was insufficient for positive regenerative adaptations and improved performance.

Comparison of resin and solution screening methodologies in combinatorial chemistry and the identification of a 100 nM inhibitor of trypanothione reductase.

Two identical polyamine peptide conjugate libraries were screened against the parasitic enzyme trypanothione reductase. One of these libraries was in a solution format, while the other was resin-based and was used in two resin-based screens (a diminution assay and a direct bead screening). Potent inhibitors (100 nM) of trypanothione reductase were identified both in the solution screen and in the resin-based screens when using the PEGA resin of Meldal. Resin screening of both types failed to work with TentaGel resin. Importantly there was excellent agreement between the solution and resin-based assays, suggesting both methods are reliable for the screening of combinatorial libraries.