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Biomedical subjects

J E James

Publications and source records attributed to J E James.

At least 19 recordsLinked to original sources
PubMed1999

Hemodynamic profile of stress-induced anticipation and recovery.

Systolic and diastolic blood pressure, heart rate, stroke volume, cardiac output, and total peripheral resistance were measured in 100 healthy men and women with the aim of investigating hemodynamic profile during anticipation of, and recovery from, exposure to active and passive laboratory stressors. A 5-min anticipatory period preceded two tasks, both of which lasted 2.5 min. The tasks were mental arithmetic ('beta-adrenergic' stress) and the cold pressor test ('alpha-adrenergic' stress). Each task was followed by a 5-min recovery period. Blood pressure and heart rate were measured with a FinaPres 2300e, and stroke volume, cardiac output, and total peripheral resistance were computed from these parameters. Salivary cortisol was measured in relation to both tasks, and participants completed tests of state and trait anxiety, locus of control, and hostility. As expected, mental arithmetic and the cold pressor test elicited myocardial and vascular patterns of reactivity, respectively. However, contrary to expectations, anticipatory and recovery hemodynamic profile involved essentially vascular responding for both stressors. Salivary cortisol increased in response to both tasks but only weakly correlated with hemodynamic changes. None of the subjective measurements was a strong predictor of physiological reactivity. The findings suggest that stress-induced anticipatory and recovery reactivity may be generally vascular rather than myocardial. This could have important implications in light of suggestions that anticipatory and recovery responses may be better predictors of subsequent cardiovascular disease than direct stress-induced reactivity.

Adolescent↗
PubMed1998

Effects of video-relayed social support on hemodynamic reactivity and salivary cortisol during laboratory-based behavioral challenge.

The authors tested the effects of a laboratory analogue of social support on reactivity to laboratory-based behavioral challenge. Video-relayed supportive commentary was provided by a same-sex confederate while participants (40 healthy men and women assigned to support and no-support groups) performed a demanding computer task, and their heart rate, systolic and diastolic blood pressure, and salivary cortisol were measured. The authors found that heart rate and cortisol level (but not blood pressure) were attenuated in the support condition for both genders. Objective performance on the task was similar in both groups, but the social support group reported higher levels of perceived support and rated the task as easier than did participants in the no-support condition. Video presentation offers new opportunities for systematically examining social support and its effects.

Adolescent↗
PubMed1998

Acute and chronic effects of caffeine on performance, mood, headache, and sleep.

Despite being the most widely consumed psychoactive substance in the world, there is considerable confusion regarding the effects of caffeine. This study examined objective indices of performance, and self-reported mood, headache, and sleep in 36 healthy male and female habitual caffeine consumers exposed to a pattern of moderate intake. A double-blind placebo-controlled cross-over design with counterbalancing was employed in which all subjects participated in four experimental conditions involving the ingestion of placebo or caffeine 3 times daily for 6 days followed by a 7th (challenge) day of placebo or caffeine ingestion. No evidence was found that caffeine improved performance, either in the context of acute or habitual use. On the contrary, performance was found to be significantly impaired when caffeine was withdrawn abruptly following habitual use. Participants reported feeling more alert and less tired following acute ingestion of caffeine, but feeling less alert in conjunction with chronic exposure to the drug. In addition, caffeine withdrawal was associated with reported increases in frequency and severity of headache, and with reports of sleeping longer and more soundly.

Acute Disease↗
PubMed1997

The psychological and emotional impact of living with an automatic internal cardioverter defibrillator (AICD): how can nurses help?

The introduction of the Automatic Internal Cardioverter Defibrillator (AICD) has greatly improved the mortality rates associated with sudden cardiac events (Moss et al 1996, McCarthy 1997, Trappe et al 1997). Little is known about the consequences of living with this device for patients and their families. Biomedical influences have resulted in the devices's success being measured on physical adaptation, with data on suitability, reliability, and efficiency of AICDs as a therapeutic measure. What seems to be of equal priority now is to obtain insights as to the emotional and psychological consequences of such treatment, and the effects these may have on outcomes and utilization of health-care resources. AICD patients have described many powerful emotions arising from receiving this device, which are often heightened at discharge, yet little is known of the reasons for this (James 1997a). It is essential that individuals' and their families' perceptions of their experiences are understood so that clinical staff can not only meet the technological and safety needs of this group, but also assist them to adjust to living with an AICD. Families of AICD patients report significant emotions arising from their support of AICD patients, and describe their own needs and problems. Nevertheless, the influence of, and the effects on the family are often underestimated within AICD patient care. A shift away from a purely individualistic approach towards a more family-centred approach is suggested, arguably enabling the role of family members to be recognized, supported and developed. Qualitative research in this area is needed to inform clinical nursing practice and assist in development of clinical expertise to address the important issues for patients and families. This should enable them to return to their everyday lives with appropriate support. Education of healthcare professionals in a wide variety of clinical areas is needed to ensure a sound body of knowledge, as a basis for development of a more holistic approach to care which encompasses and recognizes the feelings and emotions evoked from receiving this device.

Activities of Daily Living↗
PubMed1994

Chronic effects of habitual caffeine consumption on laboratory and ambulatory blood pressure levels.

BACKGROUND: Uncertainty continues to surround the role of habitual caffeine consumption as a cardiovascular risk factor. The present study examined the effects of moderate caffeine intake on 24h blood pressure and heart rate in normotensive men and women. METHODS: A double-blind, placebo-controlled, crossover design with counterbalancing was used, in which 36 healthy men and women participated in four experimental conditions involving the ingestion of placebo or caffeine three times daily for 6 days, followed by a seventh ('challenge') day of placebo or caffeine ingestion. RESULTS: When caffeine was consumed on the challenge day, blood pressure was found to be elevated immediately after caffeine ingestion and was either unchanged or decreased (hypotensive effect) after a period of abstinence from the drug. Some diminution of the peak pressor effects was found when participants ingested caffeine after habitual use of the drug (6.0/5.2 mmHg) compared with when they had been abstinent before the challenge day (7.7/6.8 mmHg). This diminution in the reaction was comparatively small, however, and pressor effects persisted on caffeine-challenge days even when caffeine was consumed on preceding days. CONCLUSION: Habitual consumption diminished, but did not eliminate, the pressor effects of caffeine. Considering the almost universal consumption of caffeine beverages, the persistent pressor effects of the drug could have important implications for cardiovascular health.

Adolescent↗
PubMed1994

Psychophysiological effects of habitual caffeine consumption.

Caffeine is the most widely consumed pharmacologically active substance in the world, and a key issue concerning its possible implications for human health is whether it has persistent (i.e., chronic) physiological effects on habitual consumers. This study examined blood pressure, heart rate (HR), electromyogram (EMG), and skin conductance level (SCL) in 36 healthy men and women exposed to a pattern of moderate intake. A double-blind placebo-controlled crossover design with counterbalancing was used in which all subjects participated in four experimental conditions involving the ingestion of placebo or caffeine three times daily for 6 days followed by a seventh ("challenge") day of placebo or caffeine ingestion. Results confirmed that caffeine has significant pressor effects, and these were found to he additive to the pressor action of a laboratory stressor. Following habitual consumption of the drug. pressor effects were diminished (indicative of tolerance) but not eliminated. Effects of caffeine on other parameters were either modest (HR and EMG) or negligible (SCL). Considering (he near-universal use of caffeine. the persistent pressor effects observed in this study have important implications for clinical practice and public health.

Journal Article↗
PubMed1991

Pressor effects of caffeine and cigarette smoking.

Pressor effects of caffeine and cigarette smoking were examined in 15 normotensive young men and women. A cross-over design was used in which all subjects participated in four separate conditions: placebo alone, caffeine alone, placebo plus smoking, and caffeine plus smoking. Caffeine and smoking produced independent increases in systolic and diastolic blood pressure, and these effects were additive in the caffeine-plus-smoking condition. Heart rate was significantly increased by smoking but was essentially unaffected by caffeine.

Adolescent↗
PubMed1990

Virtue rewarded: reinforcement and punishment in an acute psychiatric admission ward.

This study evaluated the naturally occurring behaviour of psychiatric patients in an acute psychiatric setting. Direct behavioural observations were carried out to determine the amount of time patients spent in interaction, with whom they interacted, and the nature of the interaction. Also examined were each respondent group's type and rate of interactive behavior. For much of the time no interactive behaviour was observed to occur, but much of the behaviour exhibited by patients was socially appropriate. When social interactions did occur, both fellow patients and staff tended to reinforce appropriate behaviour. However, nurses reinforced inappropriate crazy behaviour much less than did fellow-patients or non-nursing staff. Treatment implications are discussed.

Adult↗
PubMed1990

In vitro exposure of preimplantation porcine embryos to porcine parvovirus.

Early porcine embryos at the four- to eight-cell stage can be infected with either the virulent (NADL-8) or avirulent KBSH strain of porcine parvovirus (PPV) by microinjection or by incubation of embryos with virus. Treatment of embryos by microinjection of virus or incubation in media with virus did not significantly inhibit in vitro development of the embryos when compared with untreated controls. RNA-DNA hybridization was used to identify the presence of virus associated with embryos. It was found that PPV-DNA was present in viable embryos after microinjection of embryos with KBSH and NADL-8 strains of PPV and after incubation of embryos with KBSH strain. The data indicated the presence of replicative virus associated with viable porcine embryos.

Journal Article↗
PubMed1990

The influence of user status and anxious disposition on the hypertensive effects of caffeine.

The present study examined the influence of consumer status and anxious disposition on the hypertensive effects of caffeine. A secondary aim of the study was to investigate possible gender differences in response to caffeine. Sixty normotensive subjects were assigned to 4 groups representing high and low scorers on the variables of habitual caffeine consumption and anxious disposition. A randomized double-blind crossover design was used in which all subjects received a placebo (lactose) at one of two 120-min laboratory sessions and caffeine (6 mg/kg) at the other. Systolic and diastolic blood pressure, heart rate, hand steadiness, and EMG were monitored before and after exposure to a psychological stressor. Caffeine produced significant elevations in systolic and diastolic blood pressure, and these effects were additive to the pressor effects of stress and anxiety. While the general pattern of results was similar for both sexes, reactions to caffeine were more pronounced in males than in females. Notwithstanding the need for clarification of the chronic effects of caffeine, present findings add further weight to current concerns about the acute hypertensive effects of the drug.

Adult↗
PubMed1989

A preliminary analysis of the ameliorative effects of time-out from speaking on stuttering.

Relatively few attempts have been made to systematically examine the processes responsible for the ameliorative effects of response-contingent stimulation (RCS) on stuttering. It was hypothesized that the reductions in stuttering that frequently accompany RCS are the result of the stutterer being encouraged to access extant fluent speech that may not be fully evident during "contingency-free" (CF) conditions. A preliminary analysis of the hypothesis was conducted by monitoring RCS and CF stuttering frequency and speaking rate in 20 adult stutterers before, during, and after a program of fluency training. Subjects were divided into "high" and "low" responders on the basis of their baseline response to the RCS procedure of time-out from speaking, after which they participated in a 32-hour program of fluency training aimed at minimizing stuttering. After showing a degree of relapse during a subsequent 6-mon follow-up, high and low responders were found to be equally affected by time-out. This result contrasted the differential response shown by the two groups during the baseline phase, and is consistent with the hypothesis that improvements in fluency during RCS may occur when stutterers access extant fluent speech that is not otherwise being fully utilized.

Adult↗