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PubMed2001

HPLC determination of cyanuric acid in swimming pool waters using phenyl and confirmatory porous graphitic carbon columns.

The chlorinated salts of cyanuric acid have found an important role in recreational swimming pool waters across the United States. Upon application to pool water, they can (1) release disinfectant chlorine or (2) stabilize the free available chlorine by acting as chlorine reservoirs in the form of cyanuric acid, preventing the photolytic destruction of residual chlorine by sunlight. Recommended levels of the cyanuric acid stabilizer are in the 10-100 mg/L concentration range according to the National Swimming Pool Foundation (San Antonio, TX). Two isocratic HPLC methods with UV detection (213 nm) employing phenyl and porous graphitic carbon (PGC) columns and phosphate buffer eluents (pH 6.7 and pH 9.1, respectively) were developed to accurately measure cyanuric acid in swimming pools. The two methods allowed fast separation and detection of the stabilizer in 4 (phenyl) and 8 (PGC) min. Both methods offered practical sensitivities with method detection limits of 0.07 (phenyl) and 0.02 mg/L (PGC). Neither one of the two methods required the use of sample cleanup cartridges. They exhibit chromatograms with excellent baseline stability enabling low-level quantitation. Most important, the PGC column had a useful lifetime of five months and 500 sample analyses/column. Eleven pool water samples were fortified with 4.8-50.0 mg/L stabilizer, and the average recovery was 99.8%. Finally, statistical analysis on the relative precisions of the two methods indicated equivalence at the 0.05 critical level.

Chromatography, High Pressure Liquid↗
PubMed2002

Ecology of dermatophytes and other keratinophilic fungi in swimming pools and polluted and unpolluted streams.

The biodiversity and richness of keratinophilic fungal communities including dermatophytes were assessed in three stream sites and three swimming pools in the Nablus district in Palestine, using hair baiting (HBT) and surface dilution plate (SDP) techniques, over 8- and 6-month periods, respectively. The effect of wastewater effluent and selected ecological factors on these fungi in relation to species diversity and population densities were also considered. Fifty keratinophilic fungal species were recovered from the aquatic habitats studied, of which 42 were recovered from stream sites and 22 from swimming pools. Of these fungi 6 were either dermatophytes (Microsporum gypseum, and Trichophyton mentagrophytes) or dermatophyte related species (Chrysosporium merdarium, Ch. tropicum, Ch. keratinophilum and T. terrestre). The most frequently isolated species in the three pools were Acremonium strictum and Cladosporium cladosporioides, using Sabouraud dextrose agar medium (SDA). The most abundant species were Acr. strictum, and Aspergillus flavus. However, only 4 species were isolated using the SDA medium amended with 5-flurocytosine (5-FC). The most frequent and abundant species in the three stream sites using SDA medium were Geotricum candidum, and Penicillium chrysogenum. The most frequent species in the three sites using the 5-FC medium, was Paecilomyces lilacinus. Using HBT, the most abundant and frequent species in the three stream sites were G. candidum, and Pa. lilacinus, on SDA medium, and Pa. lilacinus, and Gliocladium nigrovirens on the 5-FC medium. The 5-FC medium was more suitable for the isolation of dermatophytes and closely related species than the SDA medium; 6 were recovered on 5-FC, whereas only one on the SDA medium. Variation in the levels of keratinophilic fungal populations from the three stream sites sampled 5 times over an 8-month period, followed comparable fluctuation patterns. Wastewater affected fungal population densities with the highest levels in the un-polluted stream sites, and lowest in the heavily polluted sites. Swimming pools, polluted and un-polluted stream sites were found to be rich in pathogenic and potentially pathogenic fungi.

Arthrodermataceae↗
PubMed2004

Swimming exercise in infancy has beneficial effect on the hearts in cardiomyopathic Syrian hamsters.

The phenotypic expression of cardiomyopathy is greatly influenced by extrinsic factors other than intrinsic genetic defects, such as environmental stress. Exercise is assumed to be an important extrinsic factor, since sudden death is sometimes seen during exercise in young patients with hypertrophic cardiomyopathy (HCM). However, the long-term effects of mild exercise on phenotypic expression in cardiomyopathy remain unclear. To evaluate the effects of exercise performed during infancy or adolescence in cardiomyopathic patients, cardiomyopathic Syrian hamsters (BIO14.6) were subjected to swimming. BIO14.6 and age-matched congenic normal hamsters (CN) as controls were divided into three groups: sedentary (Sed), and trained during infancy (Inf) and during adolescence (Ado). Histological and biochemical analysis of 41-week-old hamsters revealed that (1) the relative level of beta-myosin heavy chain mRNA was significantly lower in the Inf group than in the Sed and Ado groups of BIO14.6. The level in the Inf group of BIO14.6 was compatible with that in the age-matched Sed group of the CN strain; (2) in BIO14.6, degenerative mitochondrial change in the cardiomyocytes was not seen in the Inf group while it was common in the Sed and Ado groups; (3) calcineurin phosphatase activity in the swimming group in 10-week-old CN was significantly higher than that of the age-matched sedentary group, and was as much as that of the swimming and sedentary groups in 10- and 41-week-old BIO14.6.

Age Factors↗
PubMed2003

Respiratory snorkel and valve system for breath-by-breath gas analysis in swimming.

The present study aimed to compare a standard facemask (CM) and a newly modified swimming snorkel and valve system (SV) for breath-by-breath (BxB) gas analysis (K4 b2, Cosmed, Rome, Italy), and to validate the system under controlled laboratory conditions before being used in swimming. Nine healthy males performed two bouts of a stepwise exercise on an electrically braked stationary bicycle on separate days. Ventilatory and gas exchange parameters were analyzed using the same BxB portable system, with subjects breathing alternatively through the two different valves. Agreement between both methods was evaluated by Passing-Bablok regression analysis. The gas exchange values measured using the SV were highly correlated with those obtained using the CM (R2 values >0.9). However, differences existed between the two series of measurements so that most ventilatory and gas exchange parameters were lower (3-7%) with the SV. The error when using the SV device was mainly systematic along the whole range of measurement. Accordingly, linear regression equations were developed to further improve the accuracy of the measures when using the SV. Therefore, the modified respiratory SV system can be considered as a valid device for collecting expired gas for BxB analysis, comparable to the standard facemask, with the advantage of being suitable for measurements during swimming.

Adult↗
PubMed1987

Cholinergic receptor blockade produces impairments in a sensorimotor subsystem for place navigation in the rat: evidence from sensory, motor, and acquisition tests in a swimming pool.

Studies have shown that central cholinergic receptor blockade biases the behavior of rats so that they make less use of the sensorimotor behaviors that are normally used to orient to the relational properties of distal cues and that they simultaneously become more reliant on proximal cues. In Experiment 1, control rats and rats treated with atropine sulfate or atropine methyl nitrate (50 mg/kg) were trained to escape to a visible platform from different starting points in a swimming pool. All groups learned the task by concomitantly developing position responses, by orienting according to room cues, and by orienting to the platform, but probe trials showed that the atropine-sulfate group made more use of the platform as a local cue and made less use of distal cues than did the other groups. The atropine-sulfate group also made fewer searches during acquisition, made fewer searches when the platform was removed on probe trials, and were less responsive to novel cues placed above and around the pool. Swim speed, as estimated by the distance swum on probe trials, was also greater in atropine-sulfate-treated rats. The postulate that rats treated with atropine sulfate preferentially guide swimming by using position responses and local cues was tested in Experiment 2 by comparing their performance with that of control rats in a place task in which a target platform was hidden (no local cues present) and in a similar place task in which the target platform was visible, as was a second incorrect platform that sank when climbed upon (two competing local cues present). Although both tasks were acquired by the control and drugged rats, the two-platform task, as predicted, was comparatively more difficult for the atropine-treated rats. These results suggest that one effect of central cholinergic blockade is to impair the use of a sensorimotor subsystem used for place navigation.

Animals↗
PubMed1996

Habituation and iterative enhancement of multiple components of the Tritonia swim response.

To understand the relationship between memory storage sites in the brain and learned changes in behavior, the learned behavior must be characterized. However, even simple types of learning may be quite complex. Repeated elicitation of the Tritonia swim produced multiple changes in the response. Several types of acquisition curves were observed in a single experiment depending on the response component measured. Habituation (response decrement) and iterative enhancement (response facilitation) occurred simultaneously in different swim components. The acquisition curve for one component could be modulated by stimulus strength. Because the Tritonia swim neural network is well studied, it may be possible to causally relate experience-dependent behavioral changes to the underlying memory trace in this marine mollusk.

Animals↗
PubMed2000

Rats alternate on a dry-land but not swimming-pool (Morris task) place task: implications for spatial processing.

Groups of rats were rewarded with food for traveling from a start point to 2 different locations while their alternations in choice between those locations on 2 daily trials were recorded. In one experimental condition, the rats swam and received food once they climbed upon a platform that was hidden just below the surface of the water at the food location. In the other condition, the rats walked to reach the food. It was found that the rats did not alternate their choices between target locations when swimming but that they did alternate target choices when walking. Even experience in alternating when walking did not produce reliable alternation when swimming. It is proposed that rats treat escape (swimming) and search (walking) tasks in different ways, and this difference is discussed with respect to the possibility that different central processes may be used in the task solutions.

Animals↗
PubMed2003

Delta-wing function of webbed feet gives hydrodynamic lift for swimming propulsion in birds.

Most foot-propelled swimming birds sweep their webbed feet backwards in a curved path that lies in a plane aligned with the swimming direction. When the foot passes the most outward position, near the beginning of the power stroke, a tangent to the foot trajectory is parallel with the line of swimming and the foot web is perpendicular to it. But later in the stroke the foot takes an increasingly transverse direction, swinging towards the longitudinal axis of the body. Here we show that, early in the power stroke, propulsion is achieved mostly by hydrodynamic drag on the foot, whereas there is a gradual transition into lift-based propulsion later in the stroke. At the shift to lift mode, the attached vortices of the drag-based phase turn into a starting vortex, shed at the trailing edge, and into spiralling leading-edge vortices along the sides of the foot. Because of their delta shape, webbed feet can generate propulsive forces continuously through two successive modes, from drag at the beginning of the stroke, all the way through the transition to predominantly lift later in the stroke.

Animals↗
PubMed2005

Escherichia coli swim on the right-hand side.

The motion of peritrichously flagellated bacteria close to surfaces is relevant to understanding the early stages of biofilm formation and of pathogenic infection. This motion differs from the random-walk trajectories of cells in free solution. Individual Escherichia coli cells swim in clockwise, circular trajectories near planar glass surfaces. On a semi-solid agar substrate, cells differentiate into an elongated, hyperflagellated phenotype and migrate cooperatively over the surface, a phenomenon called swarming. We have developed a technique for observing isolated E. coli swarmer cells moving on an agar substrate and confined in shallow, oxidized poly(dimethylsiloxane) (PDMS) microchannels. Here we show that cells in these microchannels preferentially 'drive on the right', swimming preferentially along the right wall of the microchannel (viewed from behind the moving cell, with the agar on the bottom). We propose that when cells are confined between two interfaces--one an agar gel and the second PDMS--they swim closer to the agar surface than to the PDMS surface (and for much longer periods of time), leading to the preferential movement on the right of the microchannel. Thus, the choice of materials guides the motion of cells in microchannels.

Agar↗
PubMed2005

Mammal-like muscles power swimming in a cold-water shark.

Effects of temperature on muscle contraction and powering movement are profound, outwardly obvious, and of great consequence to survival. To cope with the effects of environmental temperature fluctuations, endothermic birds and mammals maintain a relatively warm and constant body temperature, whereas most fishes and other vertebrates are ectothermic and conform to their thermal niche, compromising performance at colder temperatures. However, within the fishes the tunas and lamnid sharks deviate from the ectothermic strategy, maintaining elevated core body temperatures that presumably confer physiological advantages for their roles as fast and continuously swimming pelagic predators. Here we show that the salmon shark, a lamnid inhabiting cold, north Pacific waters, has become so specialized for endothermy that its red, aerobic, locomotor muscles, which power continuous swimming, seem mammal-like, functioning only within a markedly elevated temperature range (20-30 degrees C). These muscles are ineffectual if exposed to the cool water temperatures, and when warmed even 10 degrees C above ambient they still produce only 25-50% of the power produced at 26 degrees C. In contrast, the white muscles, powering burst swimming, do not show such a marked thermal dependence and work well across a wide range of temperatures.

Animals↗
PubMed2006

Reduction of diet-induced obesity by a combination of tea-catechin intake and regular swimming.

OBJECTIVE: Obesity is a metabolic disorder resulting from imbalance between metabolizable energy intake and energy expenditure. It is known to be a strong risk factor for lifestyle-related diseases. Here, we investigated the effects of long-term intake of tea catechins (Cat) in combination with regular exercise (Ex) on the development of obesity in C57BL/6 mice. DESIGN: We compared body weight, adipose tissue mass, plasma parameters and beta-oxidation activity in mice fed a low-fat diet (5% triglyceride (TG); LF), a high-fat diet (30% TG; HF), a HF diet supplemented with 0.5% (w/w) tea Cat, a HF diet in addition to swimming Ex or a HF diet plus 0.5% tea Cat in addition to swimming Ex (Cat+Ex) for 15 weeks. Oxygen consumption and respiratory quotients were measured using indirect calorimetry. RESULTS: Tea-Cat intake in combination with swimming Ex suppressed HF diet-induced body-weight gain by 18 and 22%, respectively, compared to Ex and tea-Cat intake on their own. Visceral fat accumulation and the development of hyperinsulinemia and hyperleptinemia were also reduced in the HF+Cat+Ex group. Muscular beta-oxidation activity in this group was 69 and 52% higher, respectively, than that in the HF and HF+Cat groups. Lipid oxidation, determined using indirect calorimetry, was higher in the HF+Cat+Ex group, suggesting increased lipid utilization at the individual level. CONCLUSION: These results indicate that intake of tea Cat, together with regular Ex helps to reduce diet-induced obesity. This effect might be attributed, at least in part, to the activation of whole-body energy metabolism.

Adipose Tissue↗
PubMed2003

Antidepressant-like effect of different estrogenic compounds in the forced swimming test.

The present study evaluated the possible antidepressant-like action of the natural estrogen 17beta-estradiol (E(2), 2.5-10 microg/rat), the synthetic steroidal estrogen ethinyl-estradiol (EE(2), 1.25-10.0 microg/rat), and the nonsteroidal synthetic estrogen, diethyl-stilbestrol (DES, 0.25-1.0 mg/rat) in ovariectomized adult female Wistar rats using the forced swimming test (FST). The behavioral profile induced by the estrogens was compared with that induced by the antidepressants fluoxetine (FLX, 2.5-10 mg/kg) and desipramine (DMI, 2.5-10 mg/kg). In addition, the temporal course of the antidepressant-like action of the estrogenic compounds was analyzed. FLX and DMI induced an antidepressant-like effect characterized by a reduced immobility and increased swimming for FLX and decreased immobility and increased climbing for DMI. Both E(2) and EE(2) produced a decrease in immobility and an increase in swimming, suggesting an antidepressant-like action. DES did not affect the responses in this animal model of depression at any dose tested. The time course analysis of the actions of E(2) (10 microg/rat) and EE(2) (5 microg/rat) showed that both compounds induced an antidepressant-like effect observed 1 h after their injection lasting for 2-3 days.

Animals↗
PubMed2004

Total sleep deprivation decreases immobility in the forced-swim test.

Sleep deprivation can exert antidepressant effects in humans in less than 24 h, making it the fastest acting antidepressant treatment. However, it is rarely used clinically because the effect disappears once the subject goes back to sleep. An understanding of the neurobiological mechanisms underlying the antidepressant effect of sleep deprivation should help to develop new rapidly acting antidepressant strategies. In the present report, an animal model of depression (the forced-swim test) was used to determine whether the effects of total sleep deprivation parallel those obtained with antidepressant drugs. Using the disk-over-water method, rats deprived of sleep for 24 h exhibited increased swimming behavior when compared to cage control rats, mimicking the effects of serotonergic antidepressants. After 48 h, sleep-deprived rats exhibited increased swimming when compared to both cage control and stimulus control rats, demonstrating that the effect is due to sleep deprivation per se, and not to extraneous factors inherent in the sleep deprivation protocol (such as stress and movement). We believe that this paradigm can be used to study the neurobiological mechanisms of rapid antidepressant effects induced by sleep deprivation.

Analysis of Variance↗
PubMed1999

Prevalence of mycobacteria in a swimming pool environment.

A study was performed to evaluate the prevalence of non-tubercular mycobacteria in swimming pool environments. The bacteria in question were found in 88.2% of pool water samples. The most frequent species were Mycobacterium gordonae (73.5% of samples; range 1-840 cfu 100 ml - 1), M. chelonei (38.2% 2-360 cfu 100 ml - 1) and M. fortuitum (35.3% 2-250 cfu 100 ml - 1). The same species were also recovered from the water at the different phases of the treatment cycle, with relative percentages similar to those of the pool water. Shower floors and pool edges also presented high concentrations of the mycobacteria (100% of samples) and M. marinum was isolated from the surfaces of pool edges on two occasions (4.5% of samples). The swimming pool environment provides a suitable habitat for the survival and reproduction of mycobacteria. Although mycobacteria are common in swimming pools, human mycobacterial disease associated with their use is rare. Apart from superficial infections with M. marinum, the risk of more serious diseases in subjects with weakened immune systems should not be underestimated, given the widespread presence of mycobacteria that are possible opportunistic pathogens and the direct contact bathers have with the water and aerosol.

Bacteriological Techniques↗
PubMed1999

Vasopressin released within the septal brain area during swim stress modulates the behavioural stress response in rats.

The aim of the present study was to investigate the physiological significance of the neuropeptide arginine vasopressin (AVP) released within the septum, in the behavioural response of rats to stress. In the first experiment, rats were chronically implanted with a microdialysis probe aimed at the mediolateral or ventral septum to monitor the local release of AVP in response to 10 min of forced swimming in 20 degrees C warm water. Exposure to this stressor caused a significant increase in AVP release in both the mediolateral (174 +/- 21%, P < 0.01) and ventral septum (220 +/- 33%, P < 0.01). In contrast, microdialysates collected outside the mediolateral septum or in the lateral ventricle remained at prestress levels throughout the dialysis period. Furthermore, unstressed control animals failed to show significant alterations in vasopressin release in the mediolateral septum. In a second experiment, the introduction of the V1 receptor antagonist d(CH2)5Tyr(Me)AVP into the mediolateral septum via inverse microdialysis concomitant with stressor exposure caused the rats to spend an increased time floating and a reduced time swimming compared to vehicle-treated rats. This effect was acute and also detected 24 h after antagonist administration. Taken together, these findings demonstrate a significant activation of the septal vasopressinergic system in response to swim stress. Furthermore, our data support the view that AVP released within this brain area is involved in the generation of active behavioural strategies aimed at coping with new and challenging situations.

Adaptation, Psychological↗
PubMed2000

Reproducibility of diurnal variation in sub-maximal swimming.

Swimming training is characterised by the use of early morning and evening training sessions. The purpose of the present study was to investigate if the physiological and kinematic responses to swimming a typical training set are affected by time of day. Seven male collegiate swimmers (age 22 +/- 4 years; height 1.8 +/- 0.1 m; mass 82.1 +/- 4.1 kg) completed a standardised 600 m warm up followed by a 10 x 100 m sub-maximal freestyle set twice a day (06:30-08:00 h and 16:30-20:00 h) on three separate days. Swimming speed was controlled precisely throughout (limits of agreement multiplied/divided 1.00) using a new pacing device (Aquapacer, Challenge and Response, Inverurie, Scotland). Oral temperature (To), heart rate (HR), minute ventilation (VE), oxygen uptake (VO2), carbon dioxide expired (VCO2), respiratory exchange ratio (RER), capillary blood lactate (Bla), and glucose (BGL) were measured at rest and post exercise. Stroke rate (SR) and HR were measured during the first nine 100 m repetitions while rate of perceived exertion (RPE) was measured immediately after each 100 m. Significant diurnal variation was found at rest in To, HR, and VO2 on all three days and for VE and VCO2 on two of the days (P<0.05). During the training set no diurnal variation was evident in HR and SR responses or repetition times although RPE values were higher in morning trials compared to evening trials on two of the three days (P < 0.05). Post-exercise significant diurnal variation was found for To and blood glucose for two of the three days (P < 0.05). Therefore, although diurnal variation is evident at rest, there is no subsequent effect on physiological and kinematic responses during a sub-maximal training set following a standardised warm-up.

Adolescent↗
PubMed2003

Fourier-transform infrared spectrometry determination of the metabolic changes during a maximal 400-meter swimming test.

We describe the metabolic changes in the blood that appeared during a maximal 400-m swimming test in 7 male swimmers by Fourier-transform infrared spectrometry (FT-IR spectrometry). A 400-m test (255.9 +/- 6.8 s) was performed during which stroke frequency and time to complete each pool distance were recorded. In three other tests, the first 100 m, 200 m, and 300 m were swam at the same stroke frequency and velocity. Capillary blood samples were taken at rest and after tests to analyze change in plasma contents by FT-IR spectrometry. Best swimmers were characterized by higher glycemia increase at the onset of exercise (r = -0.91; p < 0.01). Lactate increase was also higher after 300 m (r = -0.97; p < 0.01). Higher amounts of fatty acids were also available at the end of exercise, as assessed by the relationships found between swimming velocity and concentrations of albumin (r = 0.96; p < 0.01), apolipoprotein C 3 (r = 0.93; p < 0.01), triglycerides (r = -0.81; p < 0.05), and fatty acids (r = 0.97; p < 0.01). This metabolic response allowed the best swimmers to maintain longer their initial swimming velocity. The best swimmers presented also higher amino-acid concentration increase during exercise (r = 0.91; p < 0.01). Therefore, performance competence originated probably from better regulation in carbohydrate, lipid, and amino-acid metabolism.

Adult↗
PubMed2005

Critical swimming speed does not represent the speed at maximal lactate steady state.

Critical power and critical swimming speed (CSS) are mathematically defined as intensities that could theoretically be maintained indefinitely without exhaustion. Several investigations have been conducted to attribute a physiological meaning to these variables, but results in swimming remain equivocal. Thus, the purpose of this study was to compare CSS with direct determination of the speed at maximal lactate steady state (S (MLSS)). Eight well-trained swimmers (aged 18.6 +/- 1.9 years) performed four tests to exhaustion (95, 100, 105, and 110 % of maximal aerobic speed [MAS]) in order to determine CSS from the distance-time relationship. S (MLSS) was determined from four sub-maximal 30-min constant intensity tests (ranging from 75 % to 90 % MAS). CSS (92.7 +/- 2.6 % MAS) was significantly higher than S (MLSS) (88.3 +/- 2.9 % of MAS) and the bias +/- 95 % limits of agreement for comparisons between CSS and S (MLSS) (0.07 +/- 0.13 m x s(-1)) indicated that the extent of disagreement was too great to use these two variables interchangeably. However, CSS and S (MLSS) were strongly correlated (r = 0.87; SEE = 0.033 m x s(-1); p < 0.01). Results from the present study demonstrate that in swimming, CSS does not represent the maximal speed that can be maintained without a continuous rise of blood lactate concentration and direct determination of S (MLSS) is necessary if precision is required in experimental studies.

Adult↗