Epidemiology of injuries among U18, U19, U21 and senior elite netball players.

Background: Despite a substantial body of literature on injuries among elite netball players in South Africa, no study reports on the timing and type of injuries and the reason for injuries. Objective: To determine the epidemiology of injuries in U18, U19, U21 and senior netball players in the Free State (FS), South Africa, over two consecutive netball seasons (2017/2018). Methods: An injury questionnaire was used to collect data on 96 eligible players. Results: A total of 48 injuries were reported. The profile of injuries revealed that 58% (n=28) of the injuries occurred during matches, 29% (n=14) during practice and 13% (n=6) during preseason training. Acute injuries accounted for 54% (n=26) of the total, while 46% (n=22) were overuse injuries. A third of all the injuries were re-injuries. The centre (C) position had the highest incidence of injuries in players (n=14; 29%). The ankle was the most frequently injured body part (n=18; 36%), followed by the lower leg and Achilles tendon (n=6; 13%) thus largely the ligaments and muscles. The overall incidence rate of injuries during match play was 33.9 injuries per 1 000 hours of match play. Conclusion: Preventative strategies should consist of ankle and lower leg strengthening and neuromuscular balance techniques. The focus should be on correct landing techniques, results of abrupt change of direction movements and short bursts of speed.

Physical and physiological profile of U18, U19, U21 and senior elite netball players.

Background: Physical and physiological profile data for elite netball players in South Africa and internationally are limited but are necessary for conditioning programme information. Objective: To determine the physical and physiological profiles of U18, U19, U21 and senior level elite netball players at provincial level in the Free State, South Africa. The information provided is by age group and playing position. The fitness of the players for South African and New Zealand netball is also given using the fitness normative data (norms). Methods: This cross-sectional, descriptive study consisted of 77 elite South African netball players. Anthropometric measurements were taken according to international standards. Fitness tests included the Star Execution Balance Test, standing broad jump, double- and single-leg vertical jump, Yo-Yo Intermittent Recovery Level 1(IR1) test, sprints over 5, 10 and 40 m, horizontal pull-ups and press-ups, the prone bridge test and anaerobic Octorepeater tests with 10 m and 20 m repeated shuttle sprints. In keeping with the descriptive nature of the study, descriptive statistics were calculated for numerical data by age group and playing position. Results: Players generally did not meet the accepted fitness standards in the following areas: press-ups (all age groups), horizontal pull-ups (senior and U21), standing broad jump (senior and U21), vertical squat jump (senior and U21), 5 m and 10 m sprints (senior and U21); anaerobic Octorepeater (senior players), and the aerobic Yo-Yo IR1 test (all age groups). Conclusion: Strength and conditioning coaches should develop training programmes to address fitness areas where players do not meet the international standards.

Microbial changes linked to the accelerated degradation of the herbicide atrazine in a range of temperate soils.

Accelerated degradation is the increased breakdown of a pesticide upon its repeated application, which has consequences for the environmental fate of pesticides. The herbicide atrazine was repeatedly applied to soils previously untreated with s-triazines for >5 years. A single application of atrazine, at an agriculturally relevant concentration, was sufficient to induce its rapid dissipation. Soils, with a range of physico-chemical properties and agricultural histories, showed similar degradation kinetics, with the half-life of atrazine decreasing from an average of 25 days after the first application to <2 days after the second. A mathematical model was developed to fit the atrazine-degrading kinetics, which incorporated the exponential growth of atrazine-degrading organisms. Despite the similar rates of degradation, the repertoire of atrazine-degrading genes varied between soils. Only a small portion of the bacterial community had the capacity for atrazine degradation. Overall, the microbial community was not significantly affected by atrazine treatment. One soil, characterised by low pH, did not exhibit accelerated degradation, and atrazine-degrading genes were not detected. Neutralisation of this soil restored accelerated degradation and the atrazine-degrading genes became detectable. This illustrates the potential for accelerated degradation to manifest when conditions become favourable. Additionally, the occurrence of accelerated degradation under agriculturally relevant concentrations supports the consideration of the phenomena in environmental risk assessments.

Fenton's reagent for the rapid and efficient isolation of microplastics from wastewater.

Fenton's reagent was used to isolate microplastics from organic-rich wastewater. The catalytic reaction did not affect microplastic chemistry or size, enabling its use as a pre-treatment method for focal plane array-based micro-FT-IR imaging. Compared with previously described microplastic treatment methods, Fenton's reagent offers a considerable reduction in sample preparation times.

Differences between rat primary cortical neurons and astrocytes in purine release evoked by ischemic conditions.

In the brain, the levels of adenosine increase up to 100-fold during cerebral ischernia; however, the roles of specific cell types, enzymatic pathways and membrane transport processes in regulating intra- and extracellular concentrations of adenosine are poorly characterized. Rat primary cortical neurons and astrocytes were incubated with [(3)H]adenine for 30 min to radiolabel intracellular ATP. Cells were then treated with buffer, glucose deprivation (GD), oxygen-glucose deprivation (OGD), 100 micro M sodium cyanide (NaCN) or 500 micro M iodoacetate (IAA) for 1 h to stimulate the metabolism of ATP and cellular release of [(3)H]purines. The nucleoside transport inhibitor dipyridamole (DPR) (10 micro M), the adenosine kinase inhibitor iodotubercidin (ITU) (1 micro M), the adenosine deaminase inhibitor EHNA (1 micro M) and the purine nucleoside phosphorylase inhibitor BCX-34 (10 micro M) were tested to investigate the contribution of specific enzymes and transporters in the metabolism and release of purines from each cell type. Our results indicate that (a). under basal conditions astrocytes released significantly more [(3)H]adenine nucleotides and [(3)H]adenosine than neurons, (b). OGD, NaCN and IAA conditions produced significant increases in [(3)H]adenosine release from neurons but not astrocytes, and (c) DPR blocked [(3)H]inosine release from both astrocytes and neurons but only blocked [(3)H]adenosine release from neurons. These data suggest that, in these experimental conditions, adenosine was formed by an intracellular pathway in neurons and then released via a nucleoside transporter. In contrast, adenine nucleotide release and extracellular metabolism to adenosine appeared to predominate in astrocytes.

Pulmonary artery blood temperature and the measurement of cardiac output by thermodilution.

Thermodilution cardiac output measurement assumes that the temperature within the pulmonary artery is stable during the measurement period. This may not be achieved in clinical practice because of temperature changes that are not solely produced by the thermal indicator. Such temperature changes constitute thermal noise. Thermal noise and how it may interfere with measurement is discussed with reference to both the injectate and the thermal filament methods of thermodilution cardiac output measurement.

Nucleoside transporter subtype expression: effects on potency of adenosine kinase inhibitors.

1. Adenosine kinase (AK) inhibitors can enhance adenosine levels and potentiate adenosine receptor activation. As the AK inhibitors 5' iodotubercidin (ITU) and 5-amino-5'-deoxyadenosine (NH(2)dAdo) are nucleoside analogues, we hypothesized that nucleoside transporter subtype expression can affect the potency of these inhibitors in intact cells. 3. Three nucleoside transporter subtypes that mediate adenosine permeation of rat cells have been characterized and cloned: equilibrative transporters rENT1 and rENT2 and concentrative transporter rCNT2. We stably transfected rat C6 glioma cells, which express rENT2 nucleoside transporters, with rENT1 (rENT1-C6 cells) or rCNT2 (rCNT2-C6 cells) nucleoside transporters. 3. We tested the effects of ITU and NH(2)dAdo on [(3)H]-adenosine uptake and conversion to [(3)H]-adenine nucleotides in the three cell types. NH(2)dAdo did not show any cell type selectivity. In contrast, ITU showed significant inhibition of [(3)H]-adenosine uptake and [(3)H]-adenine nucleotide formation at concentrations < or =100 nM in rENT1-C6 cells, while concentrations > or =3 microM were required for C6 or rCNT2-C6 cells. 4. Nitrobenzylthioinosine (NBMPR; 100 nM), a selective inhibitor of rENT1, abolished the effects of nanomolar concentrations of ITU in rENT1-C6 cells. 5. This study demonstrates that the effects of ITU, but not NH(2)dAdo, in whole cell assays are dependent upon nucleoside transporter subtype expression. Thus, cellular and tissue differences in expression of nucleoside transporter subtypes may affect the pharmacological actions of some AK inhibitors.

Adenosine permeation of a dynamic in vitro blood-brain barrier inhibited by dipyridamole.

Adenosine is an inhibitory neuromodulator in the central nervous system and has been reported to have neuroprotective properties. Using a dynamic in vitro blood-brain barrier, we investigated the hypothesis that inhibition of adenosine transporters on the lumenal side of the blood-brain barrier may decrease the loss of adenosine from the brain. Our results indicate that lumenal administration of dipyridamole, a nucleoside transport inhibitor, can inhibit adenosine permeation from the extracapillary space into the lumen.

Functional expression of a high affinity mammalian hepatic choline/organic cation transporter.

Uptake by the liver of the organic cation and essential nutrient choline is required for the hepatic synthesis of phosphatidylcholine. Uptake of other organic cations is also important for the metabolism and secretion of numerous endobiotics and drugs. Although a high affinity mammalian hepatic choline transporter has been kinetically defined, it has not been previously identified. We have developed stable transfectants of BALB/3T3 cells, using a murine member of the organic cation transporter gene family (mOct1/Slc22a1), and used these cells to characterize the transport of the organic cation choline and model organic cation tetraethylammonium (TEA). Functional expression of mOct1/Slc22a1 in BALB/3T3 cells confers the saturable, temperature-dependent uptake of choline with a K(m) of 42 micrometer, and uptake of TEA with a K(m) of 43 micrometer. We subsequently used our cell culture uptake system to kinetically define in HepG2 cells a high affinity choline uptake process, which transports choline with a K(m) similar to that of mOct1/Slc22a1 protein. We also demonstrated that organic cation transport by mOct1/Slc22a1 is inhibited by several organic cations, and that the gene is expressed in the perinatal period, at a time when phosphatidylcholine synthesis increases. We conclude that mOct1/Slc22a1 encodes a high affinity mammalian hepatic choline/organic cation transporter. This transporter may be important for hepatic phosphatidylcholine synthesis, and for the metabolism and secretion of many organic cationic drugs.

Purine uptake and release in rat C6 glioma cells: nucleoside transport and purine metabolism under ATP-depleting conditions.

Adenosine, through activation of membrane-bound receptors, has been reported to have neuroprotective properties during strokes or seizures. The role of astrocytes in regulating brain interstitial adenosine levels has not been clearly defined. We have determined the nucleoside transporters present in rat C6 glioma cells. RT-PCR analysis, (3)H-nucleoside uptake experiments, and [(3)H]nitrobenzylthioinosine ([(3)H]NBMPR) binding assays indicated that the primary functional nucleoside transporter in C6 cells was rENT2, an equilibrative nucleoside transporter (ENT) that is relatively insensitive to inhibition by NBMPR. [(3)H]Formycin B, a poorly metabolized nucleoside analogue, was used to investigate nucleoside release processes, and rENT2 transporters mediated [(3)H]formycin B release from these cells. Adenosine release was investigated by first loading cells with [(3)H]adenine to label adenine nucleotide pools. Tritium release was initiated by inhibiting glycolytic and oxidative ATP generation and thus depleting ATP levels. Our results indicate that during ATP-depleting conditions, AMP catabolism progressed via the reactions AMP --> IMP --> inosine --> hypoxanthine, which accounted for >90% of the evoked tritium release. It was surprising that adenosine was not released during ATP-depleting conditions unless AMP deaminase and adenosine deaminase were inhibited. Inosine release was enhanced by inhibition of purine nucleoside phosphorylase; ENT2 transporters mediated the release of adenosine or inosine. However, inhibition of AMP deaminase/adenosine deaminase or purine nucleoside phosphorylase during ATP depletion produced release of adenosine or inosine, respectively, via the rENT2 transporter. This indicates that C6 glioma cells possess primarily rENT2 nucleoside transporters that function in adenosine uptake but that intracellular metabolism prevents the release of adenosine from these cells even during ATP-depleting conditions.

Caffeine use in sports. A pharmacological review.

Caffeine is the most widely ingested psychoactive drug in the world. As many know, chronic use of caffeine leads to dependence, tolerance, drug craving, and upon abrupt cessation unpleasant withdrawal symptoms. Thus, caffeine fulfills pharmacological criteria by which agents are classified as drugs of abuse. Nevertheless, its use is legal and only at high, but readily attainable, levels is it banned from sport. Its use is widespread by athletes as young as 11 years of age who are seeking athletic advantage over fellow competitors. It is likely that its use will not decline any time soon because it is inexpensive, readily available, medically quite safe, socially acceptable, and by most measures legal. However, at levels allowed in sport, caffeine through its wide-ranging physiological and psychological effects increases endurance in well-trained athletes. If the goal of drug-testing and education programs in sport is to protect the health of athletes, prevent unfair advantage (cheating) and encourage ethical behavior then it seems obvious that the allowable levels of caffeine ingestion should be decreased. The alternative is to continue with policies designed largely to punish only those that get caught.

Randomized trial of diaspirin cross-linked hemoglobin solution as an alternative to blood transfusion after cardiac surgery. The DCLHb Cardiac Surgery Trial Collaborative Group.

BACKGROUND: Risks associated with transfusion of allogeneic blood have prompted development of methods to avoid or reduce blood transfusions. New oxygen-carrying compounds such as diaspirin cross-linked hemoglobin (DCLHb) could enable more patients to avoid allogeneic blood transfusion. METHODS: The efficacy, safety, hemodynamic effects, and plasma persistence of DCLHb were investigated in a randomized, active-control, single-blind, multicenter study in post-cardiac bypass surgery patients. Of 1,956 screened patients, 209 were determined to require a blood transfusion and met the inclusion criteria during the 24-h post-cardiac bypass period. These patients were randomized to receive up to three 250-ml infusions of DCLHb (n = 104) or three units of packed erythrocytes (pRBCs; n = 105). Further transfusions of pRBCs or whole blood were permitted, if indicated. Primary efficacy end points were the avoidance of blood transfusion through hospital discharge or 7 days postsurgery, whichever came first, and a reduction in the number of units of pRBCs transfused during this same time period. Various laboratory, physiologic, and hemodynamic parameters were monitored to define the safety and pharmacologic effect of DCLHb in this patient population. RESULTS: During the period from the end of cardiopulmonary bypass surgery through postoperative day 7 or hospital discharge, 20 of 104 (19%) DCLHb recipients did not receive a transfusion of pRBCs compared with 100% of control patients (P < 0.05). The overall number of pRBCs administered during the 7-day postoperative period was not significantly different. Mortality was similar between the DCLHb (6 of 104 patients) and the control (8 of 105 patients) groups. Hypertension, jaundice/hyperbilirubinemia, increased serum glutamic oxalo-acetic transaminase, abnormal urine, and hematuria were reported more frequently in the DCLHb group, and there was one case of renal failure in each group. The hemodynamic effects of DCLHb included a consistent and slightly greater increase in systemic and pulmonary vascular resistance with associated increases in systemic and pulmonary arterial pressures compared with pRBC. Cardiac output values decreased more in the DCLHb group patients after the first administration than the control group patients. At 24 h postinfusion, the plasma hemoglobin level was less than one half the maximal level for any amount of DCLHb infused. CONCLUSIONS: Administration of DCLHb allowed a significant number (19%) of cardiac surgery patients to avoid exposure to erythrocytes postoperatively.

Stimulation of nucleoside efflux and inhibition of adenosine kinase by A1 adenosine receptor activation.

Adenosine is produced intracellularly during conditions of metabolic stress and is an endogenous agonist for four subtypes of G-protein linked receptors. Nucleoside transporters are membrane-bound carrier proteins that transfer adenosine, and other nucleosides, across biological membranes. We investigated whether adenosine receptor activation could modulate transporter-mediated adenosine efflux from metabolically stressed cells. DDT1 MF-2 smooth muscle cells were incubated with 10 microM [3H]adenine to label adenine nucleotide pools. Metabolic stress with the glycolytic inhibitor iodoacetic acid (1AA, 5 mM) increased tritium release by 63% (P < 0.01), relative to cells treated with buffer alone. The IAA-induced increase was blocked by the nucleoside transport inhibitor nitrobenzylthioinosine (1 microM), indicating that the increased tritium release was primarily a purine nucleoside. HPLC verified this to be [3H]adenosine. The adenosine A1 receptor selective agonist N6-cyclohexyladenosine (CHA, 300 nM) increased the release of [3H]purine nucleoside induced by IAA treatment by 39% (P < 0.05). This increase was blocked by the A1 receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine (10 microM). Treatment of cells with UTP (100 microM), histamine (100 microM), or phorbol-12-myristate-13-acetate (PMA, 10 microM) also increased [3H]purine nucleoside release. The protein kinase C inhibitor chelerythrine chloride (500 nM) inhibited the increase in [3H]purine nucleoside efflux induced by CHA or PMA treatment. The adenosine kinase activity of cells treated with CHA or PMA was found to be decreased significantly compared with buffer-treated cells. These data indicated that adenosine A1 receptor activation increased nucleoside efflux from metabolically stressed DDT1 MF-2 cells by a PKC-dependent inhibition of adenosine kinase activity.

Use of blood products in cardiac surgery.

The quantity of blood products used perioperatively during cardiac surgery is known to vary widely between institutions. This study looked at the amount of blood products used perioperatively in 74 consecutive elective cardiac operations in one institution. The results are compared with those from other European centres and a cost analysis carried out. On average 2.33 +/- 0.74 (95% confidence interval 1.93-2.77) units of red cell concentrate were transfused perioperatively per patient. Six (8%) patients received no blood products. In addition a number of preoperative factors were studied in an attempt to identify predictors of transfusion requirements. Age, preoperative haemoglobin, female sex and red cell mass were all found to have some predictive value. In the face of increasing demands on a limited supply of blood products we question the need for cross matching more than four units of red cell concentrate in elective cardiac surgery.

Latissimus dorsi muscle: assessment of stimulation after cardiomyoplasty with Doppler US tissue imaging.

PURPOSE: To evaluate Doppler ultrasound (US) tissue imaging for assessment of stimulated skeletal muscle contraction. MATERIALS AND METHODS: Seven patients were studied after left latissimus dorsi cardiomyoplasty. Myograft contraction programmed on alternate cardiac cycles was assessed with Doppler US tissue imaging. Beat-to-beat variation in inferior wall motion was assessed by examining peak myograft velocities during 10 muscle-assisted and 10 nonassisted cardiac cycles. The temporal relationship between electrostimulation and myograft contraction, changes in cardiac geometry, and the effect of alterations in stimulation voltage and muscle synchronization were assessed. RESULTS: Significant beat-to-beat variation in velocity profile could be detected in the proximal myograft in six patients (P < .05). Potentiation of infero-posterior wall motion was measurable in five patients (mean peak systolic wall velocity: nonassisted, 2.5 cm.sec-1 +/- 0.5 [standard deviation]; assisted, 7.8 cm.sec-1 +/- 6.3). The response between stimulation voltage and inferoposterior wall velocity was sigmoid. CONCLUSION: Doppler US tissue imaging depicted the effects of myostimulator programming on muscle contraction and ventricular wall motion.

Angiotensinamide in the treatment of probable anaphylaxis to succinylated gelatin (Gelofusine).

A patient undergoing anaesthesia for coronary artery bypass surgery developed a probable anaphylactic reaction to succinylated gelatin (Gelofusine). The principal feature of the reaction was one of cardiovascular depression. An infusion of the angiotensin analogue, angiotensinamide was successful in the treatment of the reaction and allowed completion of the surgery.

A controlled trial of intra-operative autologous transfusion in cardiothoracic surgery measuring effect on transfusion requirements and clinical outcome.

We carried out a prospective, controlled trial of intra-operative autologous transfusion (IOAT) in cardiac surgery using the Haemonetics Cellsaver 4, to determine the effects on transfusion requirements and early clinical outcome. Intra-operative autologous transfusion in unselected patients resulted in a reduction in the use of red cells in patients undergoing first-time operations (IOAT median 3 units, controls median 4 units, P = 0.0023), with no difference in the use of other blood products. Post-operative haemoglobin was higher in IOAT patients (IOAT 11.6 g/dl +/- 1.1 versus controls 11.2 g/dl +/- 0.98, P < 0.001). There is therefore the potential for a further reduction in homologous blood use in the IOAT group. There was no difference in early clinical outcome in the two groups; in particular the incidence of coagulopathies was not influenced by IOAT. The routine use of IOAT would add substantially to the cost of these operations. The decision to use it must therefore be based on an assessment of the value of the reduction in risk to the patient achieved by a small reduction in homologous donor exposures.