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PubMed1996

Forced swimming behavior is not related to the corticosterone levels achieved in the test: a study with four inbred rat strains.

The behavior of four inbred strains of rats in the holeboard and the forced swimming tests, and its relationship with a physiological index of stress (serum corticosterone) were studied in adult male rats. The strains were: Fisher 344 (FIS), Lewis (LEW), Spontaneously hypertensive (SHR), and Wistar-Kyoto (WKY). In the holeboard, SHR rats were the most active and WKY the less active, the other strains showing intermediate levels of activity. During the first exposure to forced swimming WKY were far more passive than the other three strains and the same was observed during the second exposure. When corticosterone levels after this second exposure to water was determined, LEW rats showed lower values than the other three strains. Therefore, no apparent relationship between behavior and stress-induced corticosterone secretion exists. Although a single point measurement of only on physiological index of stress has important limitations, the present data do not give support to a strong relationship between the behavior of the animals in the forced swimming test and emotional reactivity to stress. It is therefore possible that forced swimming behavior might not be mainly a panic-like reaction, but the result of the tendency of the animals to adopt passive strategies in inescapable situations. Although more studies are needed to firmly establish this assumption, WKY rats might be, at least potentially, a useful model of depressive-like behavior.

Animals↗
PubMed1996

Decreased endurance to cold water swimming and delayed sexual maturity in the rat following neonatal lead exposure.

The effects of neonatal lead (Pb) exposure on ability to endure stress and on the onset of sexual maturity were investigated using rats. Sprague-Dawley dams (n = 17/treatment) were treated with or without lead acetate (0.3%) in drinking water from parturition until postnatal day (PND) 21, at which time the pups were weaned. A set of sex-balanced pairs of pups (24 male and 24 females/treatment) from randomly selected control and Pb-treated dams was tested for cold water (4 degrees C) swimming-endurance on PND 15, 21, 25 and 30. Lead treated-female pups showed significantly (P < 0.05) lower endurance on PND 21 and 30, while Pb-treated males exhibited lower (P < 0.05) endurance on PND 21 compared to their respective controls. The results of this study indicate that neonatal exposure to Pb decreased cold water swimming-endurance. Neonatal exposure to either Pb or swimming stress delayed (P < 0.002) the onset of sexual maturity in both sexes. However, exposure to both treatments masked the effect of swimming stress on the onset of maturity in females but not in males.

Analysis of Variance↗
PubMedDate not supplied

Secalonic acid D mycotoxin affects ontogeny of brain catecholamines and swimming in mice.

Suckling mice exposed to secalonic acid D (SAD) mycotoxin postnatally (by gavaging dams with 0, 15 or 25 mg/kg on postgestational days 1 to 10) or prenatally (by gavaging with 25 mg/kg on gestational day 13 to produce a positive behavioral teratogenic control group) manifested subtle preweaning neurobehavioral, neurochemical and growth deficits. Gestational length, maternal weight gain, neonatal sex ratio and physical appearance of pups at birth were unaffected by treatment. Prenatal SAD (25 mg/kg) delayed (p less than 0.05) ontogeny of swimming on postnatal days (PND) 11 and 13 and reduced norepinephrine (NE) and dopamine (DA) levels in prosencephalon on PND 7 and in cerebellum-pons on PND 7-16. In the postnatal treatment groups, pup body weight gains were decreased from PND 9-22. Swimming was delayed in the 15 mg/kg postnatal exposure group on PND 11 and 13, while 25 mg/kg delayed swimming on PND 11-15. Postnatal exposure to 25 mg/kg also reduced NE and DA levels in prosencephalon and cerebellum-pons on PND 7-16. SAD thus caused concomitant ontogenetic delays in growth, swimming behavior and brain catecholamine levels following either prenatal (transplacental) or early postnatal (transmammary) exposure. These data indicate that both in utero and lactational exposures must be considered when assessing potential risks posed to developing mammals by environmental neurotoxicants.

Animals↗
PubMed2001

Swimming behaviour in Monoporeia affinis (Crustacea: Amphipoda) - dependence on temperature and population density.

Swimming speed and swimming activity of the nocturnally active benthic amphipod Monoporeia affinis were measured in water temperatures from 3 to 18 degrees C and different population densities in the laboratory. Swimming speed increased with increasing temperature. Increasing water temperature reduced the percentage of active animals in the population, as measured by a "freeze frame" technique. At 7 and 10 degrees C a higher percentage of the population was active in higher animal densities. In all tested conditions swimming activity was highest at about 1 h after light-off and lowest shortly before the predicted time of light-on. The consequences of the documented behavioural responses to environmental stimuli are discussed in relation to population dynamics.

Journal Article↗
PubMed2026

Cell-body curvature reduces stall frequency to enhance Vibrio cholerae swimming and chemotaxis through hydrogels.

The swimming motility of the bacterial pathogen Vibrio cholerae is a virulence factor that aids in breaching the mucus layer. V. cholerae has a curved cell shape, and previous work demonstrated that loss of curvature decreases infectivity. Here, we investigate the mechanism by which curvature affects single-cell motility. We compared the chemotactic performance of wild-type curved cells and straight mutants. The two exhibit similar swimming properties in liquid and viscous solutions but differ significantly in mucus-mimicking hydrogels, where curved cells demonstrate an 86% increase in chemotactic drift. Trajectory analysis indicates comparable swimming speeds, but straight mutants experience more frequent stalls, reducing total swimming time. Stalls further reduce chemotactic performance by imposing an average reorientation down the chemical gradient, regardless of cell shape. Coarse-grained molecular dynamics simulations corroborate these results across intestinal mucus hydrogel stiffnesses and identify an optimal curvature for movement through hydrogel-like meshes, close to the pathogen's median curvature. These findings highlight cell shape's role in pathogenicity and the need to study bacterial behaviors under conditions more closely mimicking the host environment.

Vibrio cholerae↗
PubMed2002

Effect of swim up and Percoll treatment on viability and acrosome integrity of frozen-thawed bull spermatozoa.

The aim of this study was to investigate the effect of the swim up and Percoll methods to select frozen-thawed bull spermatozoa with high quality membrane and acrosomal integrity and final concentration. Semen samples from six Holstein-Friesian bulls were examined. The whole experiment was repeated three times. Before and after both treatments, spermatozoa were subjected to a double-staining method and evaluated by brightfield light microscope using 40x dry, or 100x oil immersion objectives. The concentration of spermatozoa evaluated by haemocytometer was 8.8 x 10(7)/ml after thawing, and the percentage of live cells with intact acrosome was 45.8%. Both treatments significantly increased the proportion of live spermatozoa compared with no treatment, and the use of Percoll gradient resulted in a significantly higher percentage of living cells with an intact acrosome (88.2%) than the swim up method (69.4%). The concentration of spermatozoa after Percoll separation (9.3 x 10(6)/ml) was higher than that after the swim up method (5.8 x 10(6)/ml). These results indicate that spermatozoa with a higher viability and acrosome integrity can be obtained by Percoll separation than by the swim up method. Therefore the use of Percoll-treated spermatozoa in IVF systems can be more expedient.

Acrosome↗
PubMed1999

The ultrastructure and metabolism of ejaculated tammar wallaby sperm are impaired by swim-up procedures when compared with sperm from the cauda epididymidis.

The metabolism, rate of intracellular accumulation of sugars, motility and ultrastructure of ejaculated tammar sperm were impaired by swim-up into artificial media, particularly when the cells were subsequently exposed to N-acetyl-D-glucosamine (NAG). The inclusion of hyaluronate, serum albumin, catalase or Desferal in swim-up media helped prevent deterioration of sperm motility, but failed to prevent detrimental NAG-induced metabolic and ultrastructural changes. However, the sperm were unavoidably diluted during swim-up into artificial media and their behavioural properties were modified by dilution. Thus, sperm collected from the cauda epididymidis were immotile and their rate of oxygen uptake was low in undiluted caudal epididymal semen (CES). Nevertheless, these sperm were viable, and vigorous motility was induced by 5- to 50-fold dilution in Krebs-Ringer phosphate (KRP). Sperm respiration also dramatically increased with moderate dilution (5- or 15-fold) in KRP, but decreased again at higher rates (50-fold). This suggested that motility and the metabolic properties of tammar sperm are modified both by dilution and on leaving the suppressing conditions of the epididymis. Diluted tammar epididymal sperm also displayed a Pasteur effect, but rapidly lost capacity for motility in an oxygen-depleted atmosphere. It was concluded that swim-up procedures compromise ejaculated tammar sperm by promoting dilution-induced changes. This may alter the permeability of the membrane with loss of the enzymes that process the ammonia generated during the metabolism of NAG in seminal plasma. Subsequent exposure to NAG further promotes ultrastructural damage culminating in loss of viability.

Acetylglucosamine↗
PubMed1997

Minimum size limit for useful locomotion by free-swimming microbes.

Formulas are derived for the effect of size on a free-swimming microbe's ability to follow chemical, light, or temperature stimuli or to disperse in random directions. The four main assumptions are as follows: (i) the organisms can be modeled as spheres, (ii) the power available to the organism for swimming is proportional to its volume, (iii) the noise in measuring a signal limits determination of the direction of a stimulus, and (iv) the time available to determine stimulus direction or to swim a straight path is limited by rotational diffusion caused by Brownian motion. In all cases, it is found that there is a sharp size limit below which locomotion has no apparent benefit. This size limit is estimated to most probably be about 0.6 micron diameter and is relatively insensitive to assumed values of the other parameters. A review of existing descriptions of free-floating bacteria reveals that the smallest of 97 motile genera has a mean length of 0.8 micron, whereas 18 of 94 nonmotile genera are smaller. Similar calculations have led to the conclusion that a minimum size also exists for use of pheromones in mate location, although this size limit is about three orders of magnitude larger. In both cases, the application of well-established physical laws and biological generalities has demonstrated that a common feature of animal behavior is of no use to small free-swimming organisms.

Bacterial Physiological Phenomena↗
PubMed2004

Complex flagellar motions and swimming patterns of the flagellates Paraphysomonas vestita and Pteridomonas danica.

Most flagellates with hispid flagella, that is, flagella with rigid filamentous hairs (mastigonemes), swim in the direction of the flagellar wave propagation with an anterior position of the flagellum. Previous analysis was based on planar wave propagation showing that the mastigonemes pull fluid along the flagellar axis. In the present study, we investigate the flagellar motions and swimming patterns for two flagellates with hispid flagella: Paraphysomonas vestita and Pteridomonas danica. Studies were carried out using normal and high-speed video recording, and particles were added to visualize flow around cells generating feeding currents. When swimming or generating flow, P. vestita was able to pull fluid normal to, and not just along, the flagellum, implying the use of the mastigonemes in an as yet un-described way. When the flagellum made contact with food particles, it changed the flagellar waveform so that the particle was fanned towards the ingestion area, suggesting mechano-sensitivity of the mastigonemes. Pteridomonas danica was capable of more complex swimming than previously described for flagellated protists. This was associated with control of the flagellar beat as well as an ability to bend the plane of the flagellar waveform.

Animals↗
PubMedDate not supplied

Ultrastructural and DNA fragmentation analyses in swim-up selected human sperm.

Seventeen sperm samples were evaluated by transmission electron microscopy (TEM) before and after swim-up separation. DNA-fragmentation was tested by terminal d-UTP nick end labeling (TUNEL) in unselected and selected semen samples, and the results were analyzed in relation to sperm ultrastructural characteristics detected by TEM. A significant improvement in mean numbers and percentages of structurally normal sperm was observed after swim-up selection, corresponding to a significant decrease in the percentage of necrotic and apoptotic sperm, while the percentage of sperm with immature nuclei did not change significantly. TUNEL indicated a significant decrease in chromatin-fragmented sperm after swim-up. Swim up selection based on sperm motility excludes many sperm with ultrastructural evidence of necrosis (absent or reacted acrosome, disrupted chromatin, broken plasma membrane) and apoptosis (misshapen nuclei with marginated chromatin), as confirmed by TUNEL analysis. Nevertheless, immature sperm with elliptical or roundish nuclei, misshapen acrosomes and uncondensed chromatin remain part of fertilizing pool.

Adult↗
PubMedDate not supplied

Quantitative analysis of CCR5 chemokine receptor and cytochrome P450 aromatase transcripts in swim-up spermatozoa isolated from fertile and infertile men.

We determined the CCR5 chemokine receptor and cytochrome P450 aromatase (P450arom) transcript copies number in swim-up sperm isolated from fertile and infertile men. The ejaculates were purified by centrifugation through discontinuous Percoll density gradient and swim-up techniques. RNA was isolated from sperm, treated with DNase I and reverse-transcribed into cDNA. Quantitative analysis of CCR5 and P450arom cDNA were performed by real-time quantitative (RQ-PCR) SYBR Green I analysis. There was a higher content of CCR5 and P450arom transcripts copy number in swim-up sperm of fertile than from infertile donors. The decrease in CCR5 and P450arom transcripts in swim-up sperm may be associated with male infertility.

Aromatase↗
PubMed2000

Improvement in motion characteristics and acrosome status in cryopreserved human spermatozoa by swim-up processing before freezing.

The purpose of this study was to examine if selecting a sperm population with improved motion characteristics before freezing reduces the deleterious effects of cryopreservation. Semen specimens from 15 normal donors were divided into two equal aliquots. The first aliquot received no treatment (control), and the second was processed by swim-up from a washed sperm preparation to select a sperm population with better motility and motion characteristics (swim-up). Both aliquots were cryopreserved by the liquid nitrogen vapour method. Percentage motility and motion characteristics were evaluated by computer-assisted semen analysis. Acrosome integrity as well as spontaneous and calcium ionophore-induced acrosome reactions before freezing and after thawing were assessed by fluorescein isothiocyanate conjugated peanut agglutinin combined with a supra vital dye (Hoechst-33258). Swim-up processing enabled selection of a sperm population with better motion characteristics, percentage motility and viability before freezing (P < 0.001), but with no difference in percentage of acrosome-intact spermatozoa (P = 0.63). After thawing, the swim-up specimens exhibited faster velocity and progression than untreated specimens (P < 0.001). They also had higher percentages of spermatozoa with intact acrosomes and spermatozoa able to undergo acrosome reaction in response to calcium ionophore (P < 0.05). Selecting a highly motile sperm population before freezing enhances overall post-thaw spermatozoa quality.

Acrosome Reaction↗
PubMed2000

The use of two density gradient centrifugation techniques and the swim-up method to separate spermatozoa with chromatin and nuclear DNA anomalies.

Human semen is heterogeneous in quality, not only between males but also within a single ejaculate. Differences in quality are evident, both when examining the classical parameters of sperm number, motility and morphology and in the integrity of the sperm nucleus. The aim of this study was to determine the efficiency of the PureSperm((R)), Percoll((R)) and swim-up preparation techniques to eliminate spermatozoa with nuclear anomalies. Semen samples were collected, washed and one part of the semen spread on a slide, the remainder was prepared using the swim-up, PureSperm((R)) or Percoll((R)) techniques. Spermatozoa from different fractions were fixed on slides and assessed. Sperm samples (n) from different men were stained using the chromomycin A(3) (CMA(3)) fluorochrome, which indirectly demonstrates a decreased presence of protamine (n = 31 for swim-up; n = 45 for PureSperm((R)); n = 39 for Percoll((R))). Spermatozoa prepared using PureSperm((R)) (n = 35) and Percoll((R)) (n = 37) were also examined for the presence of endogenous DNA nicks. Good quality spermatozoa should not possess DNA nicks and not stain (i.e. fluoresce) with CMA(3). When prepared using the swim-up technique the spermatozoa recovered showed no significant improvement with the CMA(3) staining. When spermatozoa were prepared using the PureSperm((R)) and Percoll((R)) techniques, a significant (P < 0.001) decrease in both CMA(3) positivity and DNA strand breakage was observed. These results indicate that both the PureSperm((R)) and Percoll((R)) techniques can enrich the sperm population by separating out those with nicked DNA and with poorly condensed chromatin.

Centrifugation, Density Gradient↗
PubMed1995

A Mono-Percoll separation technique improves sperm recovery of normal and male factor specimens when compared with the swim-up technique.

The purpose of this study was to determine the effects of a simplified 80% Mono-Percoll sperm separation procedure on both normal and male factor semen samples compared with the standard swim-up technique. The parameters examined include sperm concentration, motility and morphology, total motile functional spermatozoa and percentage recovery. Normal patients demonstrated enhanced sperm parameters with the Mono-Percoll compared with the swim-up technique for concentration (67 x 10(6) versus 42 x 10(6)/ml, P < 0.001), motility (66 versus 59%, P < 0.001), morphology (56 versus 49%, P < 0.005) and percentage recovery (60 versus 42%, P < 0.005). Male factor patients showed enhanced sperm parameters with the Mono-Percoll procedure compared with the swim-up technique for motility (53 versus 42%, P < 0.05) and percentage recovery (54 versus 29%, P < 0.005), with no significant difference in concentration and morphology. In summary, the Mono-Percoll sperm recovery procedure is significantly better than the swim-up technique for male factor patients and patients with normal sperm parameters.

Cell Separation↗
PubMed1992

Comparative auto-controlled study between swim-up and Percoll preparation of fresh semen samples for in-vitro fertilization.

This study compared swim-up and Percoll preparation of fresh semen samples for in-vitro fertilization. Sixty trials of in-vitro fertilization (IVF), 38 with normal semen and 22 with abnormal semen, comprising 734 oocytes were included in the study. Each semen sample was prepared by both a swim-up technique and a simplified discontinuous (50%, 70%, 90%) Percoll gradient. The oocytes for each trial were distributed at random between the two sperm preparations and incubated with the same number of motile spermatozoa. Percoll gradient preparation produced a significantly higher final concentration of spermatozoa than swim-up preparation (mean +/- SEM: 6.6 +/- 1.5 x 10(6)/ml versus 1.9 +/- 0.2 x 10(6)/ml; P less than 0.01) but a significantly lower sperm motility (69 +/- 2% versus 94 +/- 1%; P less than 0.001) and a lower number of normal forms (55 +/- 2% versus 64 +/- 2%; P less than 0.01). The ability of the Percoll gradient method to extract motile spermatozoa was higher than that of the swim-up technique (20 +/- 15.6% versus 0.8 +/- 13.6%). Nevertheless, the rates of fertilization (61%), fertilization failure (18%) and polyspermia (9%), embryo quality evaluated by mean embryo scores (3.8 +/- 0.3) and the mean number of spare embryos frozen per trial (1.4 +/- 0.3) were strictly identical in both groups. The 24 pregnancies (including three from frozen--thawed embryos) obtained in these 60 trials (40% per oocyte retrieval) could not be separated according to the sperm preparation method, as embryos from both groups were replaced together.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell Separation↗
PubMed1998

Evolutionary history of free-swimming and sessile lifestyles in urochordates as deduced from 18S rDNA molecular phylogeny.

Whether the ancestral chordates were free-swimming or sessile is a longstanding question that remains to be settled. Vertebrates and amphioxi are free-swimming, but the most basal chordate subphylum (the urochordates) includes both sessile and free-swimming species. Here, 1 report molecular phylogenetic analyses of 18S rDNA of urochordates to deduce which lifestyle is ancestral. This revealed a close relationship between salps and doliolids and paraphyly of the ascidians. An early divergence of larvaceans, which show a tadpole-like body plan throughout life, is also supported by the analyses. Based on this phylogeny, a free-swimming ancestor for chordates is more parsimonious than a sessile ancestor. The evolutionary history of various lifestyles of chordates from this ancestral form is proposed.

Animals↗
PubMed2003

Similar effects of cocaine and immobilization stress on the levels of heat-shock proteins and stress-activated protein kinases in the rat hippocampus, and on swimming behaviors: the contribution of dopamine and benzodiazepine receptors.

Cocaine (COC) has been reported to cause effects similar to physiological stressors in the brain neuroendocrinal system, including heat-shock protein (HSP) expression, although these effects have not been elucidated in detail. In the present study, we examined the effects of repeated (4 days) treatments with cocaine hydrochloride (35 mg/kg, i.p.) and 10 min immobilization stress (IM) on the distribution of HSP (HSP27, HSP60, HSP70, HSC70) and stress-activated protein kinase (SAPK) (SAPKalpha, SAPKbeta, SAPKgamma) immunoreactive nerve cells (positive cells) in the rat hippocampus. The swimming behaviors of the rats in the forced swimming test were also examined. In both COC and IM groups, an early enhancement (5 h time point) of hippocampal HSP (HSP27, HSP60, HSP70, HSC70) and SAPK (SAPKbeta, SAPKgamma) positive cells was observed, whereas a recovery (SAPKs) or attenuation (HSP60 and HSC70) was observed at the 24 h time point. In both groups, a depression of the swimming behaviors (attenuation in the activity counts and time until immobility) below the control level was observed at the 5 h point, but a recovery was observed at the 24 h time point. At the 48 h time point, all parameters returned to the control level. These alterations in the levels of HSPs and SAPKs, and the swimming behaviors were similar to those observed in the stress (IM) group, and were characteristic in that all of these alterations were attenuated by the benzodiazepine inverse agonist, Ro 15-4513 (5 mg/kg, i.p.), and the dopamine D1 receptor antagonist, SCH23390 (0.5 mg/kg, i.p.), which was not observed in the groups treated with another stressor-like drug (bicuculline).

Animals↗
PubMed2006

Corneal injury by anti-misting agent in swim goggles: a case report.

PURPOSE: To report a case of corneal injury by swim goggle anti-misting agent. METHODS: Case report. RESULTS: A 47-year-old man presented with ocular injury caused by swim goggle anti-misting agent. Two weeks previously, the patient felt sudden ocular pain and grit after pool water flooded his goggles while swimming. Before the patient's swim, a copious amount of anti-misting agent was sprayed inside his goggles. On examination, severe corneal epithelial defect and stroma edema of the right eye were noted. Best-corrected visual acuity (BCVA) was 20/40. Right eye corneal thickness was 625 microm. Topical corticosteroids, antibiotic eye drops, and oral tetracycline were started. After 1 week of treatment, the epithelial defect of his right cornea improved slightly. Stromal edema decreased mildly. Epithelial defect persisted at 1 month follow-up. Right eye BCVA remained 20/40. Three months after treatment, the right eye epithelial defect healed completely. Mild diffuse superficial stromal opacity was noted. BCVA improved to 20/20. At 1-year follow-up, right eye corneal thickness was 547 microm, which was thinner than the left eye. Right eye corneal endothelial cell density measured approximately 1500 cells/mm2, which was less than the left eye at 2300 cells/mm2. The faint, diffuse stromal opacity disappeared; however, white subepithelial plaques were noted in the cornea centers. After 1 month of treatment with topical corticosteroids, the plaques subsided completely. The corneas remained clear at 2-year follow-up. CONCLUSION: Anti-misting agent can cause severe corneal injuries, including persistent epithelial defects, stromal edema and opacity, endothelial cell loss, and subepithelial plaque.

Anti-Bacterial Agents↗