Women's rugby league injury claims and costs in New Zealand.

AIM: There is scarce information on rugby league injuries in female players. This paper provides an overview of the epidemiology of women's rugby league injuries requiring medical treatment and associated costs in New Zealand. METHOD: New Zealand Accident Compensation Corporation injury data for the period 1999-2007 were searched for rugby league injury cases occurring in females. Data were analysed by demographics, body region, nature/severity of injury, and medical procedure and costs. RESULTS: There were 320 moderate to serious injury claims recorded for females participating in rugby league activities over the study period. There was a mean (SD) of 37.9 (9.5) injury claims per year. The mean cost per year for the study period was $196 514 ($99,133) (£76,066 (£38,374)) with half of the injury claims occurring in New Zealand Maori. Concussion/brain injuries accounted for 3.8% of total female moderate to serious injury claims but accounted for 5.4% of female injury costs ($84,399 (£32,688)) with the highest mean cost per claim ($7033 (£2724)). The lower limb accounted for 65% of the total female injury claims and 58.7% of total injury costs ($922,296 (£356,968)). The mean cost per claim was higher for the lower limb ($4434 (£1714)) than the upper ($3331 (£1288)) limb. Clerks recorded 16.3% of the total injury claims, 20.3% of total injury costs ($319,474 (£123,211)) and had the highest mean cost per claim ($6144 (£2370)). The 25-29 age group recorded 31.9% of injury claims and 33.8% of injury costs. The 35-39 age group recorded the highest mean cost per claim ($6200 (£2392)) but only 10.9% of total claims and 13.8% of total costs. DISCUSSION: When compared with other studies in rugby league injuries, it appears that females incur substantially fewer injuries (5.7%) than males (94.3%). Although no participation data by sex are available, it is likely that participation percentages are reflected in the injury percentages. The high frequency (65%) and cost proportion (58.7%) for lower limb injuries was higher in females than in male rugby league players (previously reported as 42.4% of the injury claims and 31.5% of the total injury claim costs for the lower limb). CONCLUSIONS: Injury prevention programmes for women's rugby league should focus on the 25-29 age group and address ways to prevent concussion and lower limb injuries.

Epidemiology of cervical spine abnormalities in asymptomatic adult professional rugby union players using static and dynamic MRI protocols: 2002 to 2006.

OBJECTIVE: In this study, the prevalence of abnormalities in the cervical spine of asymptomatic professional rugby players using both static and dynamic magnetic resonance imaging (MRI) in order to improve the detection of abnormalities and prevention of related injuries was investigated. DESIGN: Prospective observational study. SETTING: French professional rugby union clubs, between 2002 and 2006. PARTICIPANTS: 206 elite male adult players. INTERVENTION: Static sagittal T2 and axial T2* fast spin echo (FSE), and dynamic sagittal single-shot FSE weighted MRI scans of the C2-C7 region were examined for the presence of abnormalities. Participants' spines were in supine neutral position for the static protocol but were allowed complete flexibility in a sagittal plane for the dynamic protocol. MAIN OUTCOME MEASUREMENTS: The medulla-to-canal ratio (MCR) was measured at every vertebral disc level for both MRI methods. When observed, anatomical abnormalities were categorised. RESULTS: Anatomical abnormalities mainly consisted of degenerative discopathy and were most frequently observed in players aged>21 years, as well as in players whose MCR was abnormally high based on medical expertise. Most MCRs that were initially assessed as intermediate with static MRI were subsequently assessed as abnormal with dynamic MRI assessment. CONCLUSIONS: Since dynamic MRI is more accurate than static techniques in examining the cervical spine, it contributes substantially to identifying the risk of spinal injuries in professional rugby players, and when used in association with clinical assessment, it can assist in preventing spinal injury.

Rugby league injuries in New Zealand: a review of 8 years of Accident Compensation Corporation injury entitlement claims and costs.

AIM: This paper provides an overview of the epidemiology of rugby league injuries and associated costs in New Zealand requiring medical treatment. METHOD: New Zealand national Accident Compensation Corporation injury data for the period 1999 to 2007 were searched for rugby league injury cases. Data were analysed by demographics, body region, nature/severity of injury, and medical procedure and costs. RESULTS: A total of 5941 injury entitlement claims were recorded over the study period with a significant decrease observed in the injury rate between the 1999-2000 and 2002-2003 reporting years. The total cost of the injuries for the study period was $42,822,048 (equivalent to pound15,916,072). The mean (SD) number of injury entitlement claims per year was 743 (271) and yearly cost was $5,352,760 (pound1,989,880) ($2,485,535 (pound923,994)). The knee was the most commonly reported injury site (225 per 1000 entitlement claims; $8,750,147 (pound3,252,020)) and soft tissue injuries were the most common injury types (474 per 1000 entitlement claims; $17,324,214 (pound6,438,599)). Accounting for only 1.8% of total injury entitlement claims, concussion/brain injuries accounted for 6.3% of injury entitlement costs and had the highest mean cost per claim ($25 347 (pound9420)). The upper and lower arm recorded the highest mean injury site claim cost of $43,096 (pound16,016) per claim. The 25-29 age group recorded 27.7% of total injury entitlement claims and 29.6% of total injury entitlement costs, which was slightly more than the 20-24 age group (27.3% claims; 24.7% costs). Nearly 15% of total moderate to serious injury entitlement claims and 20% of total costs were recorded from participants 35 years or older. DISCUSSION: This study identified that the knee was the most common injury site and soft tissue injuries were the most common injury type requiring medical treatment, which is consistent with other international studies on rugby league epidemiology. This study also highlights that the rate of injury and the average age of injured rugby league players increased over time. The high cost of concussion/brain injuries is a cause for concern as it reflects the severity of the injuries. CONCLUSION: Injury prevention programmes for rugby league should focus on reducing the risk of concussion/brain injury and knee and soft tissue injury, and should target participants in the 20-30 years old age range. More longitudinal epidemiological studies with specific details on injury mechanisms and participation data are warranted to further identify the injury circumstances surrounding participation in rugby league activities.

Training habits and injuries of masters' level football players: a preliminary report.

OBJECTIVE: To profile training habits and injuries in football players participating in a national Masters tournament. METHODS: A cross-sectional retrospective study design was used to survey male football players attending the 2008 New Zealand Masters Games. Information regarding player demographics, football injuries, football related training, and risk factors for injury were collected. RESULTS: 199 Players were recruited, with a median age of 44 yrs (range 35-73) and a median football playing history of 15 yrs (range 0-66). Irrespective of age, 112 (84%) players included a warm-up and 104 (78%) included a stretching regime in their regular training programme. In the 12 months prior to the tournament, 128 football related injuries were reported by 93 players (64 injuries/100 players or 46 injured players/100 players). The most frequently injured region was the lower limb; specifically the lower leg (n=23), ankle (n=18), hamstring (n=17), knee (n=15), and Achilles tendon (n=15). CONCLUSION: This study provides a preliminary insight into the training habits and injury profiles of Masters football players. Despite all players including some form of injury prevention strategy in their training, a significant number of players experienced an injury in the 12 months prior to the tournament.

Long-term morphology of a healing bone-tendon interface: a histological observation in the sheep model.

The purpose of this study was to examine and describe the sequence of events involved in long-term biological reconstruction of a tendon-bone interface following surgical reattachment. Patellar tendon re-attachment in the adult sheep was used to investigate and describe the biological components involved in healing and repair of a tendon enthesis. Light microscopy was used to describe the healing morphology at time intervals of 8, 12, 26, 52 and 104 weeks. By 8 weeks a collagen continuum was observed between the tendon and bone. Over time this fibrous bridge became anchored into the original tissues (tendon and bone), with the resultant enthesis resembling more a fibrous rather than the original fibrocartilagenous enthesis. The associated collagen fibrils between the two tissues gradually changed in morphology over time to reflect the fibres seen in the original tendon tissue. The fibrous tissue of the forming enthesis remained hypercellular when compared with the controls. The resultant long-term morphology may be a reflection of functional adaptation rather than anatomical replication.

Determining rigid body transformation parameters from ill-conditioned spatial marker co-ordinates.

The three-dimensional location of a body-fixed axis system is described by position and orientation parameters that can be calculated knowing local and global coordinates of three or more body-fixed markers. However, marker distribution can become ill-conditioned when marker placement is symmetrical with respect to the mean of the markers. As symmetry and ill-conditioning increases, random errors in marker locations can affect the stability of orientation parameters as a result of the mathematical approach adopted. The present study investigates the methods of Veldpaus et al. [1988; Journal of Biomechanics 21, 45], Challis [1995; Biomechanics 28, 733] and Andriacchi et al. [1998; Journal of Biomedical Engineering 120, 743] for obtaining segment orientation parameters when segment markers ranged from well-defined to highly ill-conditioned depending on the symmetry of segment markers. A novel fourth approach is also presented that enabled comparisons of the root mean square error of reconstructed marker coordinates to verify that an optimal solution was obtained. No single method produced optimal results for all axis orientation parameters when reconstructing movement trials. The best performed was the method of Veldpaus et al. [1988; Journal of Biomechanics 21, 45] based on consistent results and ease of implementation. The fourth approach presented provided a reliable method in all but the highly ill-conditioned markers, however implementation was computationally difficult. The method of Challis [1995; Biomechanics 28, 733] was only suited to well-conditioned marker sets which avoided markers lying in a single plane with symmetries in marker distribution relative to the mean. The method of Andriacchi et al. [1998; Journal of Biomedical Engineering 120, 743] produced, at best, orientation parameters that approximated the results obtained by least squares methods.

Dynamic coordinate data for describing muscle-tendon paths: a mathematical approach.

When modelling the musculoskeletal system over a range of joint angles the use of fixed points to describe muscle-tendon paths has inherent limitations. These result in fewer deflection points and the use of effective insertions to accommodate both relative marker movement and avoid muscle paths contacting bony structures. Model performance is dependent on the joint angle relative to the anatomical position where the muscle-tendon paths were defined. The present study proposes a scheme for the implementation of dynamic coordinates for describing muscle-tendon paths. For each muscle-tendon element a plane is defined in which the muscle-tendon complex acts when crossing a given joint. The muscle-tendon plane is dependent on 3D segment orientations and describes one degree of freedom, while the remaining two degrees of freedom are described by polar coordinates and locate the dynamic point in the muscle-tendon plane. The dynamic approach is implemented on four muscles of the lower limb in modelled and simulated joint movements and offers a significant improvement on previous approaches based on fixed deflection points. The scheme accommodates compound 3D rotations about joint axes, is not computationally difficult or require large data sets, and does not impose limitations on the number of points that may be defined along a muscle-tendon path.

Phylogenetic conservation of disulfide-linked, dimeric acetylcholine receptor pentamers in southern ocean electric rays.

Intact acetylcholine receptors have been purified on a novel affinity resin from three electric fish endemic to Australian waters. Their binding properties and morphology are compared with those of their northern hemisphere homolog, Torpedo marmorata. All four exhibit apparent dissociation constants, Kd, in the nanomolar range for the snake neurotoxin alpha-bungarotoxin and have a distinctive rosette-like appearance when viewed in negative stain under the electron microscope. Furthermore, these rosettes are paired, indicating that acetylcholine receptors from southern ocean electric fish exist as dimers, in the same fashion as their northern hemisphere counterparts. The cDNAs of the receptor's four subunits were sequenced from Hypnos monopterigium and the northern hemisphere counterpart, Torpedo marmorata, while cDNAs from only two subunits, alpha and delta, were able to be sequenced from Narcine tasmaniensis. The penultimate amino acid in the delta subunit of each of the newly sequenced fish species is a cysteine residue. Its conservation suggests that the mechanism for the observed dimerization of acetylcholine receptors is disulfide bond formation between the delta subunit of adjacent receptors, analogous to acetylcholine receptor dimers observed in other electric fish. It appears that this mechanism for receptor clustering is unique to acetylcholine receptors packed and organized in the specialized organs of electric fish. Alignment of the deduced protein sequences with the equivalent sequences from Torpedo californica and humans reveals a high degree of homology.

Amino acid sequence of a neurotoxic phospholipase A2 enzyme from common death adder (Acanthophis antracticus) venom.

The amino acid sequence of the first neurotoxic phospholipase A2, acanthoxin A1, purified from the venom of the Common death adder (Acanthophis antarcticus) was determined. Acanthoxin A1 shows high homology with other Australian elapid PLA2 neurotoxins, in particular Acanthin-I and -II, also from Death adder, Pseudexin A from the Red-bellied black snake (Pseudechis porphyriacus), and Pa-12a and Pa-9c from the King brown snake (Pseudechis australis). Acanthoxin A1 is a single-chain 118 amino acid residue PLA2, including 14 half cystine residues and the essential residues forming the ubiquitous calcium binding pocket and catalytic site. Critical analysis of the residues hypothesized to be important for neurotoxicity is presented.

Antiviral cytotoxic T cells cross-reactively recognize disparate peptide determinants from related viruses but ignore more similar self- and foreign determinants.

We have investigated the reactivities of cytotoxic T (Tc) cells against the two immunodominant, H-2K(k)-restricted determinants from the FLAVIVIRUS: Murray Valley encephalitis virus (MVE), MVE(1785) (REHSGNEI) and MVE(1971) (DEGEGRVI). The respective Tc cell populations cross-reactively lysed target cells pulsed with determinants from the MVE(1785)- and MVE(1971)-corresponding positions of six other flaviviruses, despite low sequence homology in some cases. Notably, anti-MVE(1785) Tc cells recognized a determinant (TDGEERVI) that shares with the determinant used for stimulation only the carboxyl-terminal amino acid residue, one of two H-2K(k) anchor residues. These reactivity patterns were also observed in peptide-dependent IFN-gamma production and the requirements for in vitro restimulation of memory Tc cells. However, the broad cross-reactivity appeared to be limited to flavivirus-derived determinants, as none of a range of determinants from endogenous mouse-derived sequences, similar to the MVE-determinants, were recognized. Neither were cells infected with a number of unrelated viruses recognized. These results raise the paradox that virus-immune Tc cell responses, which are mostly directed against only a few "immunodominant" viral determinants, are remarkably peptide cross-reactive.

Nonobese diabetic mice display elevated levels of class II-associated invariant chain peptide associated with I-Ag7 on the cell surface.

Peptide presentation by MHC class II molecules plays a pivotal role in determining the peripheral T cell repertoire as a result of both positive and negative selection in the thymus. Homozygous I-A(g7) expression imparts susceptibility to autoimmune diabetes in the nonobese diabetic mouse, and recently, it has been proposed that this arises from ineffectual peptide binding. Following biosynthesis, class II molecules are complexed with class II-associated invariant chain peptides (CLIP), which remain associated until displaced by Ag-derived peptides. If I-A(g7) is a poor peptide binder, then this may result in continued occupation by CLIP to the point of translocation to the cell surface. To test this hypothesis we generated affinity-purified polyclonal antisera that recognized murine CLIP bound to class II molecules in an allele-independent fashion. We have found abnormally high natural levels of cell surface class II occupancy by CLIP on nonobese diabetic splenic B cells. Experiments using I-A-transfected M12.C3 cells showed that I-A(g7) alone was associated with elevated levels of CLIP, suggesting that this was determined solely by the amino acid sequence of the class II molecule. These results indicated that an intrinsic property of I-A(g7) would affect both the quantity and the repertoire of self-peptides presented during thymic selection.

Venom from the platypus, Ornithorhynchus anatinus, induces a calcium-dependent current in cultured dorsal root ganglion cells.

The platypus (Ornithorhynchus anatinus), a uniquely Australian species, is one of the few living venomous mammals. Although envenomation of humans by many vertebrate and invertebrate species results in pain, this is often not the principal symptom of envenomation. However, platypus envenomation results in an immediate excruciating pain that develops into a very long-lasting hyperalgesia. We have previously shown that the venom contains a C-type natriuretic peptide that causes mast cell degranulation, and this probably contributes to the development of the painful response. Now we demonstrate that platypus venom has a potent action on putative nociceptors. Application of the venom to small to medium diameter dorsal root ganglion cells for 10 s resulted in an inward current lasting several minutes when the venom was diluted in buffer at pH 6.1 but not at pH 7.4. The venom itself has a pH of 6.3. The venom activated a current with a linear current-voltage relationship between -100 and -25 mV and with a reversal potential of -11 mV. Ion substitution experiments indicate that the current is a nonspecific cationic current. The response to the venom was blocked by the membrane-permeant Ca(2+)-ATPase inhibitor, thapsigargin, and by the tyrosine- and serine-kinase inhibitor, k252a. Thus the response appears to be dependent on calcium release from intracellular stores. The identity of the venom component(s) that is responsible for the responses we have described is yet to be determined but is probably not the C-type natriuretic peptide or the defensin-like peptides that are present in the venom.

Proteolysis of human hemoglobin by schistosome cathepsin D.

Schistosomes feed on human blood. They employ proteases to degrade hemoglobin from ingested erythrocytes, using the residues released for amino acid metabolism. However, the identity and the role of the participating protease(s) are unclear and controversial. Confocal microscopy localized schistosomal cathepsin D to the parasite gastrodermis, and revealed elevated protease expression in females. At sub-cellular level, cathepsin D was localized to superficial digestive vacuoles of the gut and to cisternae of the gastrodermal rough endoplasmic reticulum. Schistosome cathepsin D, expressed in insect cells, autoactivated at pH 3.6 to a approximately 40 kDa form that cleaved the substrates o-aminobenzoyl-Ile-Glu-Phe-nitroPhe-Arg-leu-NH(2) and hemoglobin. The NH(2)-terminal residues of mature cathepsin D of Schistosoma japonicum and Schistosoma mansoni were Asn1 and Gly1, respectively, revealing that the proregion peptide was comprised of 35 residues. The proteases cleaved hemoglobin at pH 2.5--4.6, releasing numerous fragments. S. Japonicum cathepsin D cleaved at 13 sites, S. mansoni cathepsin D at 15 sites. Early cleavage sites were alpha Phe33-Leu34 and beta Phe41-Phe42, while others included alpha Leu109-Ala-110 and beta Leu14-Trp15, demonstrating a preference for bulky hydrophobic residues at P1 and P1'. Most of the schistosomal cathepsin D cleavage sites were discrete from those of human cathepsin D. The gastrodermal location, elevated expression in females, acidic pH optima, similar substrate preferences in two species, and the discrete substrate preferences compared with human cathepsin D together provide compelling support for the hypothesis that schistosomal cathepsin D plays an integral role in hemoglobin proteolysis, and might be selectively targeted by drugs based on protease inhibition.

Phosphorylation of a new brain-specific septin, G-septin, by cGMP-dependent protein kinase.

The septins are a family of GTPase enzymes, some of which are required for the cytokinesis stage of cell division and others of which are associated with exocytosis. We purified and cloned the cDNA for a 40-kDa protein from rat brain that is a substrate for type I cGMP-dependent protein kinase (PKG). The amino acid sequences of two tryptic peptides of P40 showed high homology to the septins. Molecular cloning revealed the 358-amino acid P40 to be a new member of the septin family. P40 was named G-septin, as it is phosphorylated in vitro by PKG, but relatively poorly by the related cAMP-dependent protein kinase and not by protein kinase C. Two splice variants of G-septin (alpha and beta) were found with distinct N and C termini, but a common GTPase domain. G-septin lacks the C-terminal coiled-coil domain characteristic of all other mammalian septins and uniquely has two predicted phosphorylation site motifs for type I PKG. Photoaffinity labeling with [alpha-(32)P]GTP confirmed that G-septin is a GTP-binding protein. Northern blotting showed that G-septin mRNA (5.0 kilobases) is highly expressed in brain and undetectable in 12 other tissues, indicating that the G-septins are primarily neuronal proteins. Very low levels of 6.0-, 3.4-, and 2.6-kilobase transcripts were found in testis. Our results reveal a new class of brain-specific septins that may be regulated by PKG in neurons.

Factors associated with thoracic spinal cord injury, lesion level and rotator cuff disorders.

BACKGROUND: The study was concerned with the secondary functional compromise persons with long-term paraplegia contend with, that has been shown to be associated with wheelchair use. Of particular interest was the relationship between the level of thoracic spinal cord injury (SCI) and factors predisposing to rotator cuff disorders (RCD), one of the most common upper extremity musculoskeletal complications linked with long-term SCI. Disorders of these peri-articular structures have previously been associated with impaired trunk postural control and abnormal muscle strength ratios in both able-bodied groups and in paraplegic athletes. Despite their neurologically intact shoulder joint musculature, high-level and low-level paraplegics have different degrees of trunk and pelvic stability available to them during activities of daily living (ADL). This fundamental functional anatomical difference between high-level and low-level paraplegics had not previously been related to the diagnosis of RCD in a non-athletic long-term paraplegic population. METHODS: A descriptive cross sectional study was undertaken to demonstrate the differences in the prevalence of clinically diagnosed RCD in a high-level (n=22) and a low-level (n=20) group of persons with long-term paraplegia. Any perceived differences were then related to the functional anatomical variations between the two groups. Inferences were made based on factors predisposing to RCD known to exist among both able-bodied and paraplegic athletes. The 42 subjects completed the Wheelchair User's Shoulder Pain Index (WUSPI) to establish the presence or absence of shoulder pain and the Musculoskeletal Function Assessment (MFA) instrument to determine differences in functional ability and perceived degree of difficulty within five categories of ADL. Each participant underwent a clinical examination using validated provocative clinical tests and isometric muscle strength ratio testing. RESULTS: There was a higher prevalence of RCD in the high-level group (P=0.009) which correlated with decreased trunk control (P=0.009). Differences in ability to perform functional tasks were not shown to be greater in the high-level group, although there was a higher degree of perceived difficulty in ADL. Muscle strength imbalances between the shoulder adductors and abductors were shown to be greater in the high-level group. CONCLUSIONS: The results of this study suggest that the functional anatomical differences that exist within paraplegia contribute to the propensity of high-level paraplegic persons to suffer from RCD. These findings send a clear message to service-providers that greater acknowledgement of the differences in trunk postural control specific to the level of thoracic SCI is required. This may have implications for the prescription of wheelchairs, assistive devices and instruction for alternative ADL techniques to this specific population.

Effect of premanipulative tests on vertebral artery and internal carotid artery blood flow: a pilot study.

BACKGROUND: Neck manipulation occasionally causes stroke after trauma to the vertebral or internal carotid artery. Premanipulativ e tests involving cervical spine rotation or extension have been recommended to detect patients at risk of neurovascular ischemia. However, the effect of these procedures on extracranial blood flow is not well established, and their validity is thus controversial. OBJECTIVE: To determine the effect of premanipulative tests involving cervical spine rotation or extension on vertebral artery and internal carotid artery blood flow parameters. DESIGN: Two-group experimental study. SUBJECTS: Twenty subjects consisting of 16 patients treated with physiotherapy and four volunteers. METHODS: Subjects were tested with a recommended premanipulative protocol by both an independent physiotherapist and an investigator. One group consisted of 10 subjects with signs or symptoms indicative of neurovascular ischemia on premanipulative testing, with 10 subjects with no signs or symptoms indicative of neurovascular ischemia on premanipulative testing comprising the second group. Hemodynamic measurements for both vertebral and both internal carotid arteries were taken by use of duplex Doppler ultrasonography with color-flow imaging with the subjects in the following positions: neutral, end-range extension, 45 degrees contralateral rotation, end-range contralateral rotation, and combined end-range contralateral rotation/extension. RESULTS: The reliability of premanipulative testing was supported. Significant changes in flow velocity of the vertebral artery (and to a lesser extent of the internal carotid artery) were shown in end-range positions involving rotation and extension. No meaningful significant differences were found between the two groups. CONCLUSIONS: Screening procedures that use rotation and extension may be useful tests of the adequacy of collateral circulation. A larger study is needed to determine whether subjects testing positive significantly differ from those testing negative.

The nature and circumstances of tackle injuries in rugby union.

This study describes the nature and circumstances of injury occurring in rugby union tackles (33% of 569 injury events) using data from the Rugby Injury and Performance Project (RIPP) and provides supplementary information on the nature of tackles involving injury from analysis of videotape of tackle injury events. The most common tackle injuries in the RIPP data were sprains/strains (41%) followed by haematomas/bruising (26%). The most frequently injured body sites were the head/neck/face (22%) and the knee (17%). The ball carrier and tackler were injured in tackles in similar proportions in both RIPP and New Zealand Rugby Football Union (NZRFU) video tackle incidents. Both players were most often in motion in the tackle at the time of injury with approximately 70% of injuries occurring when the injured player was running or diving/falling to the ground. Tackle injury was most often caused by impact with another player rather than impact with the ground. The use of protective padding may reduce the risk of impact injury. The majority of tackle injuries were associated with stopping tackles to the trunk which were from the front (63%), rather than from the side or behind. Thus consideration should be given to coaching strategies or to rule changes which reduce the likelihood or prohibit front-on tackles.

Phosphorylation of splicing factor SF1 on Ser20 by cGMP-dependent protein kinase regulates spliceosome assembly.

Splicing factor 1 (SF1) functions at early stages of pre-mRNA splicing and contributes to splice site recognition by interacting with the essential splicing factor U2AF65 and binding to the intron branch site. We have identified an 80 kDa substrate of cGMP-dependent protein kinase-I (PKG-I) isolated from rat brain, which is identical to SF1. PKG phosphorylates SF1 at Ser20, which inhibits the SF1-U2AF65 interaction leading to a block of pre-spliceosome assembly. Mutation of Ser20 to Ala or Thr also inhibits the interaction with U2AF65, indicating that Ser20 is essential for binding. SF1 is phosphorylated in vitro by PKG, but not by cAMP-dependent protein kinase A (PKA). Phosphorylation of SF1 also occurs in cultured neuronal cells and is increased on Ser20 in response to a cGMP analogue. These results suggest a new role for PKG in mammalian pre-mRNA splicing by regulating in a phosphorylation-dependent manner the association of SF1 with U2AF65 and spliceosome assembly.

Warm-up effect on active and passive arthrometric assessment of knee laxity.

OBJECTIVE: To determine the influence of a warm-up protocol suitable for use in clinical settings on tibial displacement and muscle activity during arthrometric knee laxity assessment. DESIGN: Intervention study in which the subjects served as their own controls. SETTING: The Biomechanics Research Laboratory, University of Wollongong, Wollongong, New South Wales, Australia. SUBJECTS: Ten volunteers who reported no history of knee trauma or disease. INTERVENTION: A warm-up consisting of 10 minutes of ergometer cycling (60rpm) followed by two sets of three hamstring muscle stretches. MAIN OUTCOME MEASURES: Outcome measures were: (1) anterior tibial translation and knee extension force assessed using a Dynamic Cruciate Tester for each subject's right knee during active and passive testing, and (2) intensity of quadriceps and hamstring muscle activity during knee laxity testing. RESULTS: There was significantly less quadriceps activity after warm-up (t = 2.419, p = .039). However, there was no significant difference between anterior tibial translation, knee extension force, or hamstring muscle activity results before and after warm-up in either active or passive tests. CONCLUSION: A warm-up suitable for use in a clinical setting is not required before arthrometric assessment of knee laxity.

Lumbosacral loads in bedmaking.

The purpose of this study was to determine whether the introduction of larger and heavier beds which were lower to the floor increased the physical stress on employees responsible for room cleaning and bedmaking in the hospitality industry. More specifically, this study assessed the effect of bed size (single, double and king) and bed height (460 and 560 mm) on dynamic and static estimates of L5/S1 compression force and static L5/S1 shear force for six simulated components of the overall bedmaking task. Results confirmed the view that static models severely underestimate the loads on the lumbar spine under inertial lifting conditions, and also indicated that: (i) tasks with the greatest hand loads were not necessarily associated with the greatest spinal loads due to differences in the way each task was performed; (ii) L5/S1 loads produced during bedmaking may exceed recommended safe lifting limits for certain task-size height combinations; and (iii) the use of larger and heavier beds in the hospitality industry imposes increased loads on the lumbar spine. The investigation of alternative work practices designed to minimise loads on the lumbar spine is recommended.