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At least 163 records · Page 9Linked to original sources

Roller skating injuries.

An increasing number of patients who have sustained injuries while roller skating are being seen in emergency departments; more can be expected. One hundred consecutive charts of patients who presented to the emergency department after roller skating accidents were reviewed. Sixty-five percent of patients had sustained a fracture or dislocation. The areas most commonly injured were the wrist, elbow, and ankle. Those who attempt to roller skate should use proper equipment and be familiar with proper techniques for falling.

Adolescent↗

An unusual presentation of tarsal tunnel syndrome caused by an inflatable ice hockey skate.

BACKGROUND: Tarsal tunnel syndrome is a rare form of entrapment neuropathy. In athletes, it is usually the result of repetitive activity, local injury or a space-occupying lesion. Rarely, athletic footwear has been described as the primary cause of this syndrome. METHODS: A 37-year-old male recreational hockey player was examined clinically and electrophysiologically because of spreading numbness in the toes of his left foot while playing hockey and wearing inflatable ice hockey skates designed to promote a better fit. RESULTS: Clinical and electrophysiological studies revealed evidence of left medial and lateral plantar nerve involvement. Reduced amplitudes of mixed and motor plantar nerve responses with fibrillation potentials and positive sharp waves and no evidence of conduction block suggest that the primary pathology was axonal loss. Follow-up examination showed significant clinical and electrophysiological improvement after the patient stopped wearing his inflatable ice hockey skates. CONCLUSION: We report an unusual case of tarsal tunnel syndrome caused by an inflatable ice hockey skate. The patient improved clinically and electrophysiologically when he stopped wearing the boot.

Adult↗

Characteristics of bile salt uptake into skate hepatocytes.

The substrate specificity for the transporter that mediates the hepatic uptake of organic anions in freshly isolated hepatocytes of the elasmobranch little skate (Raja erinacea) was determined for bile salts and bile alcohols. The Na(+)-independent transport system exhibits a substrate specificity, which is different from the specificity of Na(+)-dependent bile salt transport in mammals. Unconjugated and conjugated di- and tri-hydroxylated bile salts inhibit uptake of cholyltaurine and cholate competitively. Inhibition is significantly greater with unconjugated as opposed to glycine- or taurine-conjugated bile salts. However, the number of hydroxyl groups in the steroid moiety of the bile salts has only minor influences on the inhibition by the unconjugated bile salts. Since the transport system seems to represent an archaic organic-anion transport system, other anions, such as dicarboxylates, amino acids and sulphate, were also tested, but had no inhibitory effect on bile salt uptake. To clarify whether bile alcohols, the physiological solutes in skate bile, share this transport system, cholyltaurine transport was studied after addition of 5 beta-cholestane-3 beta,5 alpha,6 beta-triol, 5 alpha-cholestan-3 beta-ol and 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha-triol. These bile alcohols inhibit cholyltaurine uptake non-competitively. In contrast, uptake of 5 beta-cholestane-3 alpha,7 alpha,12 alpha-triol, which is Na(+)-independent, is not inhibited by cholyltaurine. The findings further characterize a Na(+)-independent organic-anion transport system in skate liver cells, which is not shared by bile alcohols and has preference for unconjugated lipophilic bile salts.

Animals↗

Functional characteristics of skate connexin35, a member of the gamma subfamily of connexins expressed in the vertebrate retina.

Retinal neurons are coupled by electrical synapses that have been studied extensively in situ and in isolated cell pairs. Although many unique gating properties have been identified, the connexin composition of retinal gap junctions is not well defined. We have functionally characterized connexin35 (Cx35), a recently cloned connexin belonging to the gamma subgroup expressed in the skate retina, and compared its biophysical properties with those obtained from electrically coupled retinal cells. Injection of Cx35 RNA into pairs of Xenopus oocytes induced intercellular conductances that were voltage-gated at transjunctional potentials >/= 60 mV, and that were also closed by intracellular acidification. In contrast, Cx35 was unable to functionally interact with rodent connexins from the alpha or beta subfamilies. Voltage-activated hemichannel currents were also observed in single oocytes expressing Cx35, and superfusing these oocytes with medium containing 100 microm quinine resulted in a 1.8-fold increase in the magnitude of the outward currents, but did not change the threshold of voltage activation (membrane potential = +20 mV). Cx35 intercellular channels between paired oocytes were insensitive to quinine treatment. Both hemichannel activity and its modulation by quinine were seen previously in recordings from isolated skate horizontal cells. Voltage-activated currents of Cx46 hemichannels were also enhanced 1. 6-fold following quinine treatment, whereas Cx43-injected oocytes showed no hemichannel activity in the presence, or absence, of quinine. Although the cellular localization of Cx35 is unknown, the functional characteristics of Cx35 in Xenopus oocytes are consistent with the hemichannel and intercellular channel properties of skate horizontal cells.

Animals↗

Field evaluation of the Computer Science and Application's Inc. Activity monitor during running and skating training in adolescent athletes.

This study investigated the validity of the CSA activity monitor for assessment of the total amount of physical activity in adolescent athletes. Activity data were compared to data on daily energy expenditure and its derivatives measured by the doubly labeled water method. Seven athletes (speed skaters) with a mean age of 18.2+/-1.1 y were monitored twice (off-season and pre-season) by the activity monitor for eight consecutive days. The primary training during the off-season period was running whereas the pre-season period mainly involved skate training (i.e. inline skating, slideboard training, and skating imitations). Activity counts were significantly correlated to all energy estimates during the off-season period (r=0.93-0.96; P<0.01) whereas not during the pre-season period (r=0.32-0.57). A two-way multivariate analysis of variance showed a significant period effect for activity counts (668+/-163 vs. 548+/-91; P=0.026) whereas not for total daily energy expenditure (15.7+/-2.1 MJ x d(-1) vs. 16.0+/-1.0 MJ x d(-1); P=0.71). The relationship between activity counts and total daily energy expenditure seems to be affected by different training conditions. Therefore these circumstances have to be carefully considered in the interpretation of activity monitor data.

Activities of Daily Living↗

Relationships between aerobic energy cost, performance and kinematic parameters in roller ski skating.

The aims of this study were to test the hypotheses that 1) the aerobic energy cost of roller ski skating (CS) is significantly related to level of performance and 2) a significant part of inter-individual differences of CS can be explained by kinematic parameters of skating locomotion. Oxygen uptake, kinematics of the knee and ankle joint, EMG of the vastus lateralis (VL) and gastrocnemius lateralis (GL) muscles, and roller ski velocity were recorded in 13 skiers who roller skied at 19.0 +/- 0.1 km x h(-1). CS was found to be 2.51 +/- 0.35 J x kg(-1) x m(-1) and significantly correlated with the skiers' level of performance (r = 0.61; p < 0.05). Significant relationships were found between CS and 1) knee angular amplitude (r = 0.75; p < 0.01) during the concentric phase, 2) VL average EMG during the concentric phase (r = 0.72; p < 0.01) and 3) VL and GL average EMG during the eccentric phase (p < 0.05). The results of this study showed that a significant part of performance could be explained by the aerobic energy cost of locomotion in skating. It can also be suggested that differences in upper/lower body utilization and/or in mechanical efficiency may explain the differences in CS.

Adult↗

[Injuries due to inline skating].

In order to elucidate the patterns of injuries associated with in-line skating all patients with a inlineskate injury have been sampled prospectively during summer 1996. 58 patients were included in the study, aged 8 to 54 years (mean 22.2 years). The total number of injuries was 63, that is 1.1 injury in every injured skater. The upper extremity was the region most commonly injured (63.5%), with the distal radius fracture being the most common single fracture (25.4%). The most severe injuries, however, could be found in the lower extremity, including two femoral neck fractures and one pertrochanteric fracture in three patients aged more than 35 years. 22.4% of patients required hospitalization up to 54 days, and 36.2% of injuries had to be treated operatively. The most common single procedure was closed reduction and percutaneous wire fixation of displaced radius fractures. It is concluded that in-line skating imposes a risk of severe injuries especially on first-time skaters aged 35 years and up. The typical skating injury is the fracture of the wrist, a fact pointing out the necessity of the use of appropriate safety gear.

Adolescent↗

Risk factors for injuries from in-line skating and the effectiveness of safety gear.

BACKGROUND: Of the estimated 22.5 million people participating in in-line skating in the United States in 1995, about 100,000 were sufficiently injured so as to require emergency department care. We investigated the effectiveness of wrist guards, elbow pads, knee pads, and helmets in preventing skating injuries. METHODS: We used data from the 91 hospital emergency departments participating in the National Electronic Injury Surveillance System, a national probability sample of randomly selected hospitals with 24-hour emergency departments. Injured in-line skaters who sought medical attention between December 1992 and July 1993 were interviewed by telephone. We conducted a case-control study of skaters who injured their wrists, elbows, knees, or heads as compared with skaters with injuries to other parts of their bodies. RESULTS: Of 206 eligible injured subjects, 161 (78 percent) were interviewed. Wrist injuries were the most common (32 percent); 25 percent of all injuries were wrist fractures. Seven percent of injured skaters wore all the types of safety gear; 46 percent wore none. Forty-five percent wore knee pads, 33 percent wrist guards, 28 percent elbow pads, and 20 percent helmets. The odds ratio for wrist injury, adjusted for age and sex, for those who did not wear wrist guards, as compared with those who did, was 10.4 (95 percent confidence interval, 2.9 to 36.9). The odds ratio for elbow injury, adjusted for the number of lessons skaters had had and whether or not they performed trick skating, was 9.5 (95 percent confidence interval, 2.6 to 34.4) for those who did not wear elbow pads. Non-use of knee pads was associated with a nonsignificant increase in the risk of knee injury (crude odds ratio, 2.2; 95 percent confidence interval, 0.7 to 7.2). The effectiveness of helmets could not be assessed. CONCLUSIONS: Wrist guards and elbow pads are effective in protecting in-line skaters against injuries.

Adolescent↗

Volume expansion stimulates p72(syk) and p56(lyn) in skate erythrocytes.

Hypotonic volume expansion of skate erythrocytes rapidly stimulates the tyrosine phosphorylation of band 3, the membrane protein thought to mediate the osmotically sensitive taurine efflux. Skate erythrocytes possess numerous tyrosine kinases including p59fyn, p56lyn, pp60(src), and p72(syk), demonstrated by immune complex assays measuring autocatalytic kinase activity. Inclusion of the cytoplasmic domain of band 3 in this assay showed that only Syk and Lyn can directly phosphorylate the cytoplasmic domain of band 3. Upon cell volume expansion, Syk activity was increased as assessed by three different assays (immune complex assay measuring autophosphorylation, assay of the level of phosphotyrosine of the immunoprecipitated kinase, and assay of level of 32P in the kinase immunoprecipitated from cells prelabeled with 32PO4 and then volume-expanded). The tyrosine kinase Lyn was also stimulated by volume expansion, most notably when analyzed by the latter two methods. Volume expansion stimulated a large increase in the ability of Syk to phosphorylate band 3 at times that coincide with the stimulation of taurine flux. The stilbene piceatannol inhibited Syk preferentially over Lyn and other tyrosine kinases and inhibited volume-stimulated taurine efflux in a concentration-dependent manner similar to that for the inhibition of Syk. Two major phosphorylation peaks were detected in tryptic digests of cdb3 separated by reverse phase HPLC. Edman degradation demonstrated a phosphotyrosine in a YXXL motif. In conclusion, p72(syk) appears to be a strong candidate as a pivotal signal-transducing step in the volume-activated taurine efflux in skate red cells. The level of band-3 phosphorylation may be regulated, in addition, by a protein-tyrosine phosphatase of the 1B variety.

Animals↗

Home advantage in speed skating: evidence from individual data.

Home advantage is a well-documented phenomenon in many sports. Home advantage has been shown to exist for team sports (soccer, hockey, football, baseball, basketball) and for countries organizing sports tournaments like the Olympics and World Cup Soccer. There is also some evidence for home advantage in some individual sports, but there is a much more limited literature. This paper addresses the issue of home advantage in speed skating. From a methodological point of view, it is difficult to identify home advantage, because skaters vary in their abilities and the conditions of tournaments vary. There is a small but significant home advantage using a generalized linear mixed model, with random effects for skaters and fixed effects for skating rinks and seasons. Even though the home advantage effect exists, it is very small when compared to variation in skating times due to differences of rinks and individual abilities.

Competitive Behavior↗

Wheels-in-line roller skating injuries.

Injuries sustained by patients using wheels-in-line roller skates were reviewed in a survey of 57 cases collected by the Roosevelt Hospital Hand Service and 444 cases compiled by the Consumer Product Safety Commission. Most patients were novice skaters in the second and third decades of life. Severe distal radius fractures and upper extremity soft-tissue trauma were the most common injuries in both groups. The distal radius (44.9%), scaphoid (13.9%), and radial head (10.4%) were the three most common fracture sites in the Roosevelt survey. Most (80%) skaters in this group did not wear protective equipment. In-line roller skating can and does produce disabling injuries. Also, several deaths were reported among skaters traveling in heavy traffic. To reduce the number of injuries, all skaters should wear protective gear, especially wrist and elbow pads. Splints reduce but do not eliminate the potential for trauma. In our study most injured skaters had not mastered controlled skating and stopping techniques. This new recreational sport is increasing in popularity and more injuries are expected if skaters fail to protect themselves properly.

Accidents, Traffic↗

Impact shock and attenuation during in-line skating.

Although impact and shock attenuation associated with foot contact during running has been studied extensively, much less is known about these phenomena during in-line skating (ILS). The purpose of this study was to describe these impact characteristics for ILS and to test the hypothesis that there is lower impact shock during ILS than in running at preferred velocities. Subjects ran and skated on a treadmill at preferred velocity, with low-mass accelerometers attached to both the distal tibia and head. Tibia and head acceleration data during stance were used to calculate peak acceleration (PA), peak frequency (PF), and median frequency (MedF). Impact attenuation (IA) between the tibia and head was quantified by comparison of PA values and by calculating a transfer function between the head and tibia frequency spectra. PA, PF, and MedF values were significantly lower in ILS than in running for both tibial and head data, whereas ILS was similar between the two movements. The ILS condition exhibited almost no power in the frequency range between 10 and 20 Hz, which has been associated with the foot impacting the ground. It is concluded that in-line skating results in less impact shock to the body with each foot contact, and may be a useful exercise modality for those wishing to reduce impact shock during aerobic training.

Adult↗

Zinc enhances ionic currents induced in skate Müller (glial) cells by the inhibitory neurotransmitter GABA.

We describe here a novel effect of zinc on GABA receptors of glial cells in the skate retina. The GABA-induced currents of skate Müller cells, the radial glia of the retina, are mediated by activation of GABA(A) receptors (GABAARS). In other parts of the nervous system, GABz*-)ediated currents are inhibited by zinc. However, in isolated, voltage-clamped Müller cells, coapplication of zinc (10 microM) and GABA (1 microM) resulted in enhancement of the GABA(A)R current. Surprisingly, zinc alone induced a current similar in many respects to that elicited by GABA, i.e. the reversal potential was the same as for the GABA-induced current, the current was blocked by bicuculline and picrotoxin, and the current-voltage relation obtained in the presence of 10 microM zinc was virtually identical to that obtained with 1 microM GABA. Both bicuculline and picrotoxin suppressed a current that was present with cells bathed only in Ringer, suggesting that some of the GABA channels were spontaneously open in the absence of externally applied GABA. This possibility was supported by cell-attached patch recordings. Under conditions in which potassium and calcium currents were suppressed, spontaneous channel activity was observed. Moreover, the frequency of these channel openings was greater when zinc was included in the pipette solution, and reduced when bicuculline was added. These findings suggest that zinc acts directly to enhance the GABA(A) receptor activity of the Müller cells, and raise the possibility that the subunit composition of the GABA(A)Rs of skate Müller cells differs from that of GABA(A)Rs identified previously in other neuronal and glial preparations.

Animals↗

Bilateral femoral stress fractures in a child due to in-line (roller) skating.

We report a child who presented with a limp following 6 weeks of strenuous roller skating. Directed X-rays on admission were normal but a 99mTc-methylene diphosphanate bone scan demonstrated increased uptake in the mid-thirds of the femurs compatible with grade IV stress fracture. Immediate abstention from roller skating for 5 weeks resulted in a complete cure. The "new" side effect of this increasingly popular sport is discussed with regard to paediatric stress fractures and to other roller skating-associated injuries.

Child, Preschool↗

The 1982 epidemic--roller skating injuries.

A series of 100 roller skating injuries is presented. Roller skating injuries have been occurring at a higher rate than the previously reported skateboarding epidemic of 1977. The severity of injury has been lower, 32% fractures and dislocations occurring whilst roller skating, compared to 60% whilst skateboarding. In particular a striking reduction is seen in ankle fractures. Fifty questionnaires detailing method of injury were analysed.

Adolescent↗

Lack of biliary lipid excretion in the little skate, Raja erinacea, indicates the absence of functional Mdr2, Abcg5, and Abcg8 transporters.

The ABC transporters bile salt export pump (BSEP; encoded by the ABCB11 gene), MDR3 P-glycoprotein (ABCB4), and sterolin 1 and 2 (ABCG5 and ABCG8) are crucial for the excretion of bile salt, phospholipid, and cholesterol, respectively, into the bile of mammals. The current paradigm is that phospholipid excretion mainly serves to protect membranes of the biliary tree against bile salt micelles. Bile salt composition and cytotoxicity, however, differ greatly between species. We investigated whether biliary phospholipid and cholesterol excretion occurs in a primitive species, the little skate, which almost exclusively excretes the sulphated bile alcohol scymnolsulphate. We observed no phospholipid and very little cholesterol excretion into bile of these animals. Conversely, when scymnolsulphate was added to the perfusate of isolated mouse liver perfusions, it was very well capable of driving biliary phospholipid and cholesterol excretion. Furthermore, in an erythrocyte cytolysis assay, scymnolsulphate was found to be at least as cytotoxic as taurocholate. These results demonstrate that the little skate does not have a system for the excretion of phospholipid and cholesterol and that both the MDR3 and the two half-transporter genes, ABCG5 and ABCG8, have evolved relatively late in evolution to mediate biliary lipid excretion. Little skate plasma membranes may be protected against bile salt micelles mainly by their high sphingomyelin content.

ATP Binding Cassette Transporter, Subfamily B↗

Enterohepatic circulation of scymnol sulfate in an elasmobranch, the little skate (Raja erinacea).

The sulfated bile alcohol scymnol sulfate (ScyS), 3 alpha,7 alpha,12 alpha,24 xi, 26,27-hexahydroxy-5 beta-cholestane-26(27)-sulfate, is the major bile salt in bile of an elasmobranch, the little skate. To investigate hepatic transport of bile alcohols in skate liver, [3H]ScyS and a potential precursor, 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestane (chtriol), were used as model compounds. Their transport into isolated hepatocytes was partially saturable, temperature sensitive, and Na+ independent. The uptake of ScyS was inhibited by cholyltaurine, and uptake of cholyltaurine was inhibited by ScyS in a competitive manner. In contrast, uptake of chtriol was not inhibited by cholyltaurine, suggesting separate transport systems. ScyS and chtriol showed a choleretic effect in isolated perfused livers. When ScyS was added to the perfusate of isolated perfused livers, > 25% was found in bile within 7 h. When chtriol was added to the perfusate, 10% of the dose was secreted into the bile mainly in the form of polar metabolites, whereas only nonmetabolized chtriol remained in the livers. The slow bile flow of 40-50 microliters/h and the high recovery in the liver suggest that metabolism may be the rate-limiting step in the hepatic elimination of chtriol. The major metabolites secreted into bile were identified by mass spectrometry and chromatography as scymnol and ScyS. To study the enterohepatic circulation, [3H]ScyS or [3H]chtriol was administered into the duodenum of free-swimming skates, and bile was collected through exteriorized indwelling cannulas over a 4-day period. More than 90% of the radioactivity was recovered from bile, indicating that there was a highly effective absorption in the intestinal epithelium, as well as specific transport mechanisms for hepatic uptake and biliary secretion of these compounds. This is the first direct demonstration of an enterohepatic circulation for a bile alcohol sulfate in fish liver.

Animals↗

Intracellular signals and volume regulatory response in skate erythrocytes.

The volume regulatory response of erythrocytes (RBCs) of the little skate Raja erinacea subjected to 30% dilution of their medium is mimicked by the application of phorbol ester or calcium ionophore, implicating protein kinase C and phosphoinositide metabolism in that response. To investigate the signaling link between dilution of the medium and cell response, we measured levels of inositol phosphates (associated with intracellular calcium release) and of diacylglycerol (the physiological activator of protein kinase C) in control and hyposmotically treated RBCs. Labeled inositol monophosphate (IP1) was significantly higher in osmotically shocked than in control cells. Inositol bis- and trisphosphate levels (IP2 and IP3) were low and did not alter with dilution treatment. Separation of the isomers in the IP1 fraction indicated that the dilution effect was likely to result from the breakdown of phosphatidylinositol directly, without the involvement of the IP3 and related messenger molecules. Hyposmotic treatment also elevated the diacylglycerol content of the skate RBCs, providing evidence for the activation of protein kinase C as part of the volume regulatory response. The results are interpreted as indicating that the response to hypotonic media in skate erythrocytes is mediated primarily by protein kinase C and any involvement of calcium is associated with that pathway rather than with the production and metabolism of IP3.

Animals↗