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1.
Chron Respir Dis ; 21: 14799731241238435, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38553857

RESUMEN

OBJECTIVES: This study aimed to determine the feasibility of a group-based pilot programme of low-to-moderate physical activity training, education and social activities, by investigating acceptability, practicality, implementation and efficacy testing. We offer suggestions on programme adaptions for future study. METHODS: People with a range of chronic respiratory diseases were invited to participate in a pilot 12 week group activity programme. Activities included outdoor walking, tai-chi, education and a range of social activities. Acceptability was determined by participant experiences determined during interviews. Practicality was determined by programme and outcome measure completion, cost and adverse events. Implementation was determined according to whether the programme ran as planned. Efficacy was determined by statistical analyses of outcomes including hand grip strength, timed up and go test, COPD Helplessness Index, COPD Assessment Test, and measures of physical activity via accelerometry. RESULTS: Thematic analysis indicated that the "BreatheHappy" programme was acceptable. Seven of nine participants completed eight out of 10 sessions and the majority completed all outcome measures. "BreatheHappy" was therefore considered practical. The programme was not implemented as planned, with only 10 sessions running rather than the 12 intended. There was a significant increase in daily step counts (MD: 1284 95% CI: 240-2329 p: 0.024 effect size: 0.988), stepping time (MD: 16 min 95% CI: 5-27 min p: 0.011 effect size: 1.36) and daily minutes completing light physical activity (MD: 23 95% CI: 6-38 p: 0.006 effect size: 1.6). However, time spent sitting for ≥30 min but ≤60 min significantly increased (MD: 26 95% CI: 0.2-52 min p: 0.049 effect size: 0.931), showing signs of efficacy and changing physical activity behaviour patterns. DISCUSSION: A 10-week programme of low-moderate physical activity training, education and social activities shows signs of feasibility for future research. Suggested adaptions for future study include using physical activity measures such as daily step count or light physical activity for a primary outcome, and mental health and social health related outcome measures relatable to participant's beneficial experiences of the programme. Recruitment in future studies will try and reach both those less socially active and possibly those who have completed pulmonary rehabilitation (PR). Venues should be close to efficient transport links whilst different frequencies and durations of programme delivery should be trialled. Adequate funding should be provided for both staff running the programme and blinded research staff for outcome measurement.


Asunto(s)
Fuerza de la Mano , Enfermedad Pulmonar Obstructiva Crónica , Humanos , Estudios de Factibilidad , Equilibrio Postural , Estudios de Tiempo y Movimiento , Enfermedad Pulmonar Obstructiva Crónica/rehabilitación , Calidad de Vida
2.
Neuroimage ; 232: 117874, 2021 05 15.
Artículo en Inglés | MEDLINE | ID: mdl-33609667

RESUMEN

Slot machines are a popular form of gambling, offering a tractable way to experimentally model reward processes. This study used a 3-reel slot paradigm to assess psychologically distinct phases of reward processing, reflecting anticipation, and early- and late-stage outcome processing. EEG measures of winning, nearly missing (a losing outcome revealed at the final, third reel), and "totally" missing (a losing outcome revealed earlier, at the second reel) were collected from healthy adults (n=54). Condition effects were evaluated in: i) event-related potential (ERP) components reflecting anticipatory attention (stimulus preceding negativity, SPN) and outcome processing (reward positivity, RewP and late-positive potential, LPP) and ii) total power and phase synchrony of theta and delta band oscillations. Behaviorally, trial initiation was fastest after a near miss outcome and slowest after a winning outcome. As expected, a significant SPN was observed for possible wins (AA) vs. total misses (AB), consistent with reward anticipation. Larger win (AAA) vs. near miss (AAB) amplitudes were observed for the RewP; LPP amplitudes were largest for wins (AAA), intermediate for near misses (AAB), and smallest for total misses (ABC), reflecting significant early (RewP) and late-stage (LPP) outcome processing effects. There was an effect of reel position on the RewP, with larger amplitude in the final reel (AAA-AAB) relative to the 2nd-reel locked difference waves (AA-AB). Across all outcomes, near misses elicited the largest and most phase-synchronized theta responses, while wins elicited larger and more phase-synchronized delta responses than total misses, with delta band measures not distinguishing between near misses and wins. . Phase locking measures contrasting win vs. near miss delta and theta synchronization, within time windows corresponding to ERP measurements, covaried with RewP, but not SPN or LPP, amplitude. Lastly, EEG measures showed differential relationships with age and self-reported consummatory pleasure. In the context of slot machine play, where reward anticipation and attainment place minimal demands on effort and skill, ERP and time-frequency methods capture distinct neurophysiological signatures of reward anticipation and outcome processing.


Asunto(s)
Anticipación Psicológica/fisiología , Electroencefalografía/métodos , Juego de Azar/fisiopatología , Tiempo de Reacción/fisiología , Recompensa , Percepción del Tiempo/fisiología , Adulto , Femenino , Juego de Azar/psicología , Humanos , Masculino , Persona de Mediana Edad , Adulto Joven
3.
Anxiety Stress Coping ; 34(3): 266-278, 2021 05.
Artículo en Inglés | MEDLINE | ID: mdl-33141603

RESUMEN

It has been well established that challenge and threat evaluations affect the performance of potentially stressful tasks. However, the factors that influence these evaluations have rarely been examined. Objective: This study examined the effects of ego depletion on challenge and threat evaluations during a public speaking task. Method: 262 participants (150 males, 112 females; Mage = 20.5, SD = 4.3) were randomly assigned to either an ego depletion or control group. Participants then completed self-report measures of trait self-control. The ego depletion group performed a written transcription task requiring self-control, while the control group transcribed the text normally. Before the public speaking task, participant's challenge and threat evaluations and subjective ratings of performance were assessed via self-report items. Results: The results of independent t-tests supported the effectiveness of the self-control manipulation. There were no significant differences between the ego depletion and control groups in terms of challenge and threat evaluations or subjective performance. Additional correlation analyses revealed that trait measures of self-control were significantly and negatively related to challenge and threat evaluations and subjective performance. Conclusion: Findings suggest that ego depletion might not influence appraisals of potentially stressful tasks, and thus add to recent evidence questioning the ego-depletion phenomenon.


Asunto(s)
Atención , Ego , Autocontrol/psicología , Habla , Estrés Psicológico/psicología , Adulto , Femenino , Humanos , Masculino , Adulto Joven
4.
J Sports Sci ; 37(11): 1235-1241, 2019 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-30558476

RESUMEN

Intermittent exposure to hypoxia can lead to improved endurance performance. Currently, it is unclear whether peripheral adaptions play a role in improving oxygen delivery and utilization following both training and detraining. This study aimed to characterize skeletal muscle blood flow (mBF), oxygen consumption (mV̇O2), and perfusion adaptations to i) 4-weeks handgrip training in hypoxic and normoxic conditions, and ii) following 4-weeks detraining. Using a randomised crossover design, 9 males completed 30-min handgrip training four times a week in hypoxic (14% FiO2 ~ 3250m altitude) and normoxic conditions. mBF, mV̇O2 and perfusion were assessed pre, post 4-weeks training, and following 4-weeks detraining. Hierarchical linear modelling found that mV̇O2 increased at a significantly faster rate (58%) with hypoxic training (0.09 mlO2·min-1 · 100g-1 per week); perfusion increased at a significantly (69%) faster rate with hypoxic training (3.72 µM per week). mBF did not significantly change for the normoxic condition, but there was a significant increase of 0.38 ml· min-1 · 100ml-1 per week (95% CI: 0.35, 0.40) for the hypoxic condition. During 4-weeks detraining, mV̇O2 and perfusion significantly declined at similar rates for both conditions, whereas mBF decreased significantly faster following hypoxic training. Four weeks hypoxic training increases the delivery and utilisation of oxygen in the periphery.


Asunto(s)
Antebrazo/irrigación sanguínea , Hipoxia , Microcirculación , Músculo Esquelético/irrigación sanguínea , Consumo de Oxígeno , Acondicionamiento Físico Humano/métodos , Adaptación Fisiológica , Estudios Cruzados , Antebrazo/fisiología , Fuerza de la Mano , Hemodinámica , Humanos , Modelos Lineales , Masculino , Músculo Esquelético/fisiología , Espectroscopía Infrarroja Corta , Adulto Joven
5.
Eur J Sport Sci ; 17(9): 1177-1183, 2017 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-28753391

RESUMEN

This study examined differences in the oxygenation kinetics and strength and endurance characteristics of boulderers and lead sport climbers. Using near infrared spectroscopy, 13-boulderers, 10-lead climbers, and 10-controls completed assessments of oxidative capacity index and muscle oxygen consumption (m⩒O2) in the flexor digitorum profundus (FDP), and extensor digitorum communis (EDC). Additionally, forearm strength (maximal volitional contraction MVC), endurance (force-time integral FTI at 40% MVC), and forearm volume (FAV and ΔFAV) was assessed. MVC was significantly greater in boulderers compared to lead climbers (mean difference = 9.6, 95% CI 5.2-14 kg). FDP and EDC oxidative capacity indexes were significantly greater (p = .041 and .013, respectively) in lead climbers and boulderers compared to controls (mean difference = -1.166, 95% CI (-3.264 to 0.931 s) and mean difference = -1.120, 95% CI (-3.316 to 1.075 s), respectively) with no differences between climbing disciplines. Climbers had a significantly greater FTI compared to controls (mean difference = 2205, 95% CI= 1114-3296 and mean difference = 1716, 95% CI = 553-2880, respectively) but not between disciplines. There were no significant group differences in ΔFAV or m⩒O2. The greater MVC in boulderers may be due to neural adaptation and not hypertrophy. A greater oxidative capacity index in both climbing groups suggests that irrespective of climbing discipline, trainers, coaches, and practitioners should consider forearm specific aerobic training to aid performance.


Asunto(s)
Antebrazo/fisiología , Hemodinámica , Montañismo/fisiología , Fuerza Muscular , Músculo Esquelético/fisiología , Consumo de Oxígeno , Resistencia Física , Adulto , Dedos/fisiología , Fuerza de la Mano , Humanos , Masculino , Espectroscopía Infrarroja Corta , Adulto Joven
6.
Int J Sports Med ; 36(2): 137-42, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-25251449

RESUMEN

Currently it is unclear whether blood flow (BF) or muscle oxidative capacity best governs performance during intermittent contractions to failure. The aim of this study was to determine oxygenation kinetics and BF responses during intermittent (10 s contraction: 3 s release) contractions at 40% of MVC in rock climbers of different ability (N=38). Total forearm BF, as well as de-oxygenation and re-oxygenation of the flexor digitorum profundus (FDP) and the flexor carpi radialis (FCR) were assessed. Compared to the control, intermediate and advanced groups, the elite climbers had a significantly (p<0.05) greater force time integral (FTI), MVC and MVC/kg. Furthermore, the elite climbers de-oxygenated the FDP significantly more during the first (7.8, 11.9, 12.4 vs. 15.7 O2%) and middle (7.3, 8.8, 10.4 vs.15.3 O2%) phases of contractions as well as for the FCR during the first phase only (8.3, 7, 11.7 vs. 13.3 O2%). They also had a significantly higher BF upon release of the contractions (656, 701, 764 vs. 971 mL ∙ min(-1)). The higher FTI seen in elite climbers may be attributable to a greater blood delivery, and an enhanced O2 recovery during the 3 s release periods, as well as a superior muscle oxidative capacity associated with the greater de-oxygenation during the 10 s contractions.


Asunto(s)
Dedos/irrigación sanguínea , Antebrazo/irrigación sanguínea , Hemodinámica , Montañismo/fisiología , Músculo Esquelético/irrigación sanguínea , Adulto , Humanos , Contracción Isométrica , Masculino , Músculo Esquelético/fisiología , Consumo de Oxígeno , Flujo Sanguíneo Regional
8.
Scand J Med Sci Sports ; 23(5): 645-50, 2013 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-22299663

RESUMEN

Research suggests that lead climbing is both physiologically and psychologically more stressful than top rope climbing for intermediate performers. This observation may not be true for advanced climbers, who train regularly on lead routes and are accustomed to leader falls. The aim of this study was to compare the psychophysiological stresses of lead and top rope on-sight ascents in advanced rock climbers. Twenty-one climbers (18 men and three women) ascended routes near or at the best of their ability (22 Ewbank). Psychological stress was measured preclimb using the Revised Comparative State Anxiety Inventory (CSAI-2R). Plasma cortisol was sampled at six intervals. The volume of oxygen (VO2 ) and heart rate (Hr) were measured throughout the climbs. No significant differences were found in self-confidence, somatic, or cognitive anxiety between the conditions lead and top rope. No significant differences in plasma cortisol concentration were found between any time points. No significant relationships were found between cortisol and any CSAI-2R measures. No significant differences were found between conditions for VO2 or blood lactate concentration. During the lead climb, Hr was significantly elevated during the last part of the route. Findings suggest that advanced rock climbers do not find lead climbing to be more stressful than top rope climbing during an on-sight ascent.


Asunto(s)
Montañismo/psicología , Resistencia Física/fisiología , Estrés Fisiológico/fisiología , Estrés Psicológico/fisiopatología , Adulto , Análisis de Varianza , Biomarcadores/sangre , Femenino , Frecuencia Cardíaca/fisiología , Humanos , Hidrocortisona/sangre , Ácido Láctico/sangre , Masculino , Montañismo/fisiología , Nueva Zelanda , Consumo de Oxígeno/fisiología , Psicofisiología , Autoimagen , Estrés Psicológico/sangre , Estrés Psicológico/etiología
9.
J Sports Med Phys Fitness ; 52(6): 688-95, 2012 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-23187334

RESUMEN

AIM: Blood samples for the determination of plasma cortisol concentration are generally obtained via venipuncture or capillary sampling at the fingertip. During rock climbing the upper body, forearms and fingertips are subject to continual loading and gripping making sampling at these sites problematic. The purpose of this study was to examine differences in plasma cortisol concentrations from capillary samples taken at the fingertip and first (big) toe in a rock climbing context. METHODS: Nine (8 males, 1 female) climbers completed a succession of climbing bouts at three different angles (91°,100° and 110°). Capillary blood samples were taken simultaneously from the fingertip and first toe pre and post climb at each angle. Plasma samples were collected via centrifugation and subsequently analysed for cortisol using an Enzyme-Linked Immunosorbent Assay (ELISA) kit. All standards and samples were analysed in duplicate. Intra assay coeffiecients of variation (CV%) were 5.91% and 7.94% for finger and toe respectively. RESULTS: A limits of agreement plot revealed all data points to be well within upper and lower bounds of the 95% population confidence interval. Paired samples t-tests (for finger and toe) indicated there were no significant differences between sample sites. Subsequent regression analysis revealed a strong relationship (R2=0.78, y=1.031x - 2.079) between fingertip and first toe capillary plasma cortisol concentrations. CONCLUSION: Findings suggest that the first toe offers a valid alternative sampling site for plasma cortisol concentration in a rock climbing context.


Asunto(s)
Hidrocortisona/sangre , Montañismo/fisiología , Resistencia Física/fisiología , Adulto , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Ácido Láctico/sangre , Masculino , Manejo de Especímenes/métodos
10.
Int J Sports Med ; 33(10): 842-5, 2012 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-22592547

RESUMEN

Venepuncture is the established "gold standard" for sampling cortisol, but it is expensive, highly invasive and impractical for many experimental and clinical settings. Salivary free cortisol is a non-invasive and practical alternative; however, when cortisol concentrations exceed 500 nmol · L there is a lack of agreement between salivary (free) and venous (bound) cortisol. No known research has assessed whether capillary cortisol accurately reflects venous blood cortisol across a range of concentrations. The objective of the current study was to determine the agreement between capillary and venous blood samples of total plasma cortisol across a range of concentrations. 11 healthy male subjects (26.1 ± 5.3 years) were recruited. Capillary and venous blood samples were collected pre and post (immediately post and post 5, 10, 15 and 20 min) a treadmill VO2max test. Regression analysis revealed a strong relationship (R2=0.96, y=1.0028x + 1.2964 (P<0.05)) between capillary and venous cortisol concentrations. A Bland-Altman plot showed all data was within the upper and lower bounds of the 95% confidence interval, and no systematic bias was evident. In conclusion, capillary sampling is a valid technique for measuring bound cortisol across a range of concentrations.


Asunto(s)
Capilares/fisiología , Ejercicio Físico/fisiología , Hidrocortisona/sangre , Venas/fisiología , Adulto , Humanos , Masculino , Consumo de Oxígeno/fisiología , Punciones , Análisis de Regresión , Reproducibilidad de los Resultados , Saliva/química , Saliva/fisiología , Adulto Joven
11.
Int J Sports Med ; 33(1): 13-7, 2012 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-21984397

RESUMEN

Previous research suggested plasma cortisol concentrations in response to rock climbing have a cubic relationship with state anxiety and self-confidence. This research, however, was conducted in a situation where the climbers had previously climbed the route. The purpose of our study was to examine this relationship in response to on-sight climbing. Nineteen (13 male, 6 female) intermediate climbers volunteered to attend anthropometric and baseline testing sessions, prior to an on-sight ascent (lead climb or top-rope) of the test climb (grade 19 Ewbank/6a sport/5.10b YDS). Data recorded included state anxiety, self-confidence and cortisol concentrations prior to completing the climb. Results indicated that there were no significant differences in state anxiety, self-confidence and plasma cortisol concentration regardless of the style of ascent (lead climb or top-rope) in an on-sight sport climbing context. Regression analysis indicated there was a significant linear relationship between plasma cortisol concentrations and self-confidence (r= - 0.52, R2=0.267, p=0.024), cognitive (r=0.5, R2=0.253, p=0.028), and somatic anxieties (r=0.46, R2=0.210, p=0.049). In an on-sight condition the relationships between plasma cortisol concentrations with anxiety (cognitive and somatic) and self-confidence were linear.


Asunto(s)
Ansiedad/etiología , Hidrocortisona/sangre , Montañismo/psicología , Autoimagen , Adulto , Antropometría , Ansiedad/sangre , Femenino , Humanos , Masculino , Análisis de Regresión , Adulto Joven
12.
J Sports Med Phys Fitness ; 51(3): 417-25, 2011 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-21904280

RESUMEN

AIM: The popularity of rock climbing has resulted in a growing research base for the sport. However, at present there is a lack of sport-specific measures of performance in the field. The aim of this study was to examine the use of the powerslap test as a sport specific power measure. METHODS: The participants in this study were categorised into four different ability groups (novice, intermediate, advanced and elite) based on self reported lead grade. Two separate experiments were conducted to determine validity and reliability. The powerslap test was conducted on a revolution board with two variations - wide and narrow grip, for both sides of the body. The test started with the climber hanging at full extension from two holds from which a pull up movement was made releasing one hand to slap a scaled score board above. RESULTS: There was a significant relationship between powerslap scores and climbing ability (Left Wide: r=0.7, P<0.0005; right wide: r=0.69, P<0.0005; left narrow: r=0.73, P<0.0005; right narrow: r =0.72, P<0.0005). Further to this, scores on the powerslap narrow test were significantly differentiated by climber ability (LEFT: F(3,37)=15.74, P<0.0005; right: F(3,37)=12.16, P<0.0005). Limits of agreement and intra-class correlation indicated that the powerslap test is a reliable performance measure. CONCLUSION: According to the present findings the narrow grip variation of the powerslap test is a useful sport-specific power test that is related to climbing performance.


Asunto(s)
Montañismo/fisiología , Fuerza Muscular/fisiología , Resistencia Física/fisiología , Adulto , Umbral Anaerobio , Análisis de Varianza , Rendimiento Atlético/fisiología , Femenino , Humanos , Masculino , Estadísticas no Paramétricas
13.
Int J Sports Med ; 32(6): 428-32, 2011 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-21380969

RESUMEN

Comparisons of capillary blood lactate concentrations pre and post climb have featured in the protocols of many rock climbing studies, with most researchers obtaining samples from the fingertip. The nature of rock climbing, however, places a comparatively high physiological loading on the foreaand fingertips. Indeed, the fingertips are continually required for gripping and this makes pre-climb sampling at this site problematic. The purpose of our study was to examine differences in capillary blood lactate concentrations from samples taken at the fingertip and first (big) toe in a rock climbing context. 10 participants (9 males and 1 female) completed climbing bouts at 3 different angles (91°, 100° and 110°). Capillary blood samples were taken simultaneously from the fingertip and first toe pre and post climb. A limit of agreement plot revealed all data points to be well within the upper and lower bounds of the 95% population confidence interval. Subsequent regression analysis revealed a strong relationship (R (2)=0.94, y=0.940x + 0.208) between fingertip and first toe capillary blood lactate concentrations. Findings from our study suggest that the toe offers a valid alternative site for capillary blood lactate concentration analysis in a rock climbing context.


Asunto(s)
Recolección de Muestras de Sangre/métodos , Ácido Láctico/sangre , Deportes/fisiología , Adulto , Capilares , Femenino , Dedos/irrigación sanguínea , Humanos , Masculino , Análisis de Regresión , Dedos del Pie/irrigación sanguínea , Adulto Joven
14.
Br J Sports Med ; 43(7): 531-5, 2009 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-18411238

RESUMEN

OBJECTIVES: To examine how different safety rope protocols impact on subjective anxiety and self-confidence levels and plasma cortisol concentrations and the relationship between subjective states and cortisol during rock climbing. METHODS: Participants (n = 12) were tested in three climbing conditions that were designed to invoke low, moderate and high physical and mental stress. Plasma cortisol concentrations were collected before and after climbing and participants reported subjective anxiety and self-confidence states for each climb. RESULTS: Repeated measures analysis of variance showed significant differences between conditions for somatic anxiety (F(2, 22) = 7.74, p = 0.009), self-confidence (F(2, 22) = 9.52, p = 0.001) and change in plasma cortisol concentration (F(2, 22) = 3.71, p = 0.041). Preplanned polynomial comparisons showed that these were linear effects; somatic anxiety was higher in the higher stress conditions whilst self-confidence was lower. Plasma cortisol concentration change was also linear. Regression analyses showed cubic relationships between plasma cortisol concentration and cognitive anxiety (R(2) = 0.452), self-confidence (R(2) = 0.281) and somatic anxiety (R(2) = 0.268). CONCLUSIONS: There is a relationship between plasma cortisol concentration and subjective anxiety and self-confidence states during rock climbing. Changes in the way the safety rope is organised can impact on anxiety, cortisol concentration and self-confidence during rock climbing.


Asunto(s)
Ansiedad/etiología , Hidrocortisona/sangre , Montañismo/psicología , Equipos de Seguridad , Adulto , Análisis de Varianza , Ansiedad/sangre , Biomarcadores/sangre , Humanos , Masculino , Análisis de Regresión , Autoeficacia
15.
Int J Eat Disord ; 22(4): 427-36, 1997 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-9356891

RESUMEN

OBJECTIVE: This study explored the relationship between stressors and disturbed eating attitudes among adolescent females, assessing the moderating role of coping and the mediating influence of poor self-esteem. METHOD: Two hundred eighty-six teenage girls were recruited from local schools, and completed standardized measures of stressors, coping, self-esteem, perfectionism, and disturbed eating attitudes. Regression analyses were used to test for moderating and mediating effects. RESULTS: Stressors and emotion-focused coping were found to be associated with low self-esteem, which in turn was strongly associated with disturbed eating attitudes. Stressors were also directly related to disturbed eating attitudes. DISCUSSION: The findings provide partial support for existing models of the etiology and maintenance of eating psychopathology, but have wider implications for our understanding of the eating disorders and their treatment.


Asunto(s)
Adaptación Psicológica , Actitud , Ingestión de Alimentos , Estrés Psicológico/complicaciones , Adolescente , Imagen Corporal , Mecanismos de Defensa , Femenino , Humanos , Inventario de Personalidad/estadística & datos numéricos , Psicometría , Autoimagen
16.
J Parasitol ; 82(2): 332-5, 1996 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-8604109

RESUMEN

Behavior of hemocytes of the gastropod mollusc Biomphalaria glabrata was markedly changed on plastic by treatment of the substrate with 0.1 mg/ml poly-L-lysine compared to behavior on untreated plastic. On lysine, the cells showed minimal spreading, moved significantly faster, and formed aggregates. Cell-mediated cytotoxicity (CMC) assays were set up on the modified and untreated substrates to compare the killing capacities of B. glabrata hemocytes against Schistosoma mansoni sporocysts. Hemolymph from 1316-R1 (resistant) snails showed higher killing in lysine-treated wells; no significant difference in sporocyst mortality was observed in MO (susceptible) hemolymph between treated and untreated wells. The CMC assays on poly-L-lysine-treated plastic were used to compare the kinetics of parasite killing in hemolymph from 2 susceptible (MO, MRLc) and 2 resistant (1316-R1, 10R2) host strains. Marked differences could be observed between the two resistant snail strains, suggesting different mechanisms of parasite recognition, killing, or both.


Asunto(s)
Biomphalaria/inmunología , Hemocitos/efectos de los fármacos , Hemolinfa/inmunología , Polilisina/farmacología , Schistosoma mansoni/inmunología , Animales , Biomphalaria/clasificación , Adhesión Celular , Agregación Celular , Citotoxicidad Inmunológica , Hemocitos/citología , Hemocitos/inmunología , Cinética , Microscopía de Contraste de Fase , Plásticos , Grabación en Video
17.
J Parasitol ; 82(2): 343-7, 1996 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-8604113

RESUMEN

The hemolymph of Biomphalaria glabrata, a molluscan host of Schistosoma mansoni, contains an alpha-macroglobulin proteinase inhibitor (alphaM). In this study we have demonstrated that this host molecule inhibits a cysteine proteinase produced by larval S. mansoni. Inhibition by alphaM involves conformational changes through proteolytic cleavage by the proteinase, thus the enzyme must be active for interactions to occur. A specific cysteine proteinase inhibitor (E64) was used to block the interaction between parasite cysteine proteinase and host alphaM during an in vitro parasite killing assay. Increased sporocyst mortality was not observed in hemolymph from susceptible strains of B. glabrata when E64 was included, nor was there decreased killing in similarly treated hemolymph from a resistant strain. This suggests that the inhibition of this parasite proteinase by host alphaM is not involved in processes determining either resistance or susceptibility to this trematode.


Asunto(s)
Biomphalaria/metabolismo , Inhibidores de Cisteína Proteinasa/farmacología , Hemolinfa/química , Schistosoma mansoni/enzimología , alfa-Macroglobulinas/farmacología , Animales , Biomphalaria/parasitología , Cisteína Endopeptidasas/aislamiento & purificación , Cisteína Endopeptidasas/metabolismo , Inhibidores de Cisteína Proteinasa/sangre , Inhibidores de Cisteína Proteinasa/aislamiento & purificación , Interacciones Huésped-Parásitos , Larva/efectos de los fármacos , Larva/enzimología , Schistosoma mansoni/efectos de los fármacos , Schistosoma mansoni/fisiología , alfa-Macroglobulinas/aislamiento & purificación
19.
Dev Comp Immunol ; 20(1): 39-50, 1996.
Artículo en Inglés | MEDLINE | ID: mdl-8738935

RESUMEN

Commercial immunoassay kits that incorporate monoclonal antibodies are being used increasingly to screen tissues and plasma from invertebrates for the presence of antigens that are taken to be homologues of the vertebrate immunogen. We report the presence of a protein (BgL115r) in the plasma of Biomphalaria glabrata that binds to immunoglobulins from a variety of vertebrates. BgL115r (ca. 230 kD non-reduced, ca. 115 kD reduced on SDS-PAGE) binds to the F(ab')2-region of murine IgG. Binding could be inhibited with high concentrations of N-acetyl-D-glucosamine (GlcNAc). BgL115r was found to yield false positive signals in an ELISA based assay.


Asunto(s)
Biomphalaria/inmunología , Ensayo de Inmunoadsorción Enzimática , Hemolinfa/inmunología , Inmunoglobulinas/metabolismo , Linfocinas/inmunología , Proteínas de Secreción Prostática , Animales , Reacciones Falso Positivas , Ratones , Unión Proteica , Juego de Reactivos para Diagnóstico
20.
Dev Comp Immunol ; 20(1): 23-37, 1996.
Artículo en Inglés | MEDLINE | ID: mdl-8738934

RESUMEN

Circulating phagocytes of the mollusc Biomphalaria glabrata help determine the fate of invading Schistosoma mansoni larvae. In mediating cytotoxicity against this trematode parasite, phagocytic hemocytes may interact with unidentified plasma components. In this study, positively and negatively charged latex beads were coated with plasma for use in in vitro phagocytosis assays. Hemocytes from S. mansoni-susceptible and -resistant strains of B. glabrata were tested for their ability to internalize beads coated with homologous and heterologous plasma components. Electrophoretic analysis showed that differences in the plasma polypeptides adsorbed to latex beads were charge-related, but no consistent strain-specific differences were detected. Hemocytes from a susceptible strain phagocytosed negatively charged latex pretreated in plasma form a resistant strain of snail at a higher rate than beads treated in plasma from the susceptible strain. Pretreatment of susceptible hemocytes with resistant plasma reduced subsequent phagocytosis of beads coated with resistant plasma, consistent with blocking of receptors on the susceptible hemocytes with resistant strain plasma components. Exogenous lectins detected no differences in the carbohydrates on beads coated with plasma from either snail strain. However, strain differences in endogenous lectins are suggested by differential binding of neoglycoproteins to plasma coated beads. The plasma component(s) responsible for the differential phagocytosis of beads treated in the two plasma strains by hemocytes from the susceptible strain of B. glabrata remain(s) to be identified.


Asunto(s)
Biomphalaria/inmunología , Hemocitos/inmunología , Hemolinfa/inmunología , Fagocitosis , Animales , Aniones , Cationes , Glicoproteínas/metabolismo , Hemolinfa/química , Lectinas/metabolismo , Modelos Inmunológicos , Unión Proteica , Propiedades de Superficie
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