Biomedical subjects

J Carrier

Publications and source records attributed to J Carrier.

At least 19 recordsLinked to original sources

PubMed2002

REM sleep behavior disorder and REM sleep without atonia in Parkinson's disease.

OBJECTIVE: To determine the frequency of REM sleep behavior disorder (RBD) among patients with PD using both history and polysomnography (PSG) recordings and to further study REM sleep muscle atonia in PD. BACKGROUND: The reported occurrence of RBD in PD varies from 15 to 47%. However, no study has estimated the frequency of RBD using PSG recordings or analyzed in detail the characteristics of REM sleep muscle atonia in a large group of unselected patients with PD. METHODS: Consecutive patients with PD (n = 33) and healthy control subjects (n = 16) were studied. Each subject underwent a structured clinical interview and PSG recording. REM sleep was scored using a method that allows the scoring of REM sleep without atonia. RESULTS: One third of patients with PD met the diagnostic criteria of RBD based on PSG recordings. Only one half of these cases would have been detected by history. Nineteen (58%) of 33 patients with PD but only 1 of 16 control subjects had REM sleep without atonia. Of these 19 patients with PD, 8 (42%) did not present with behavioral manifestations of RBD, and their cases may represent preclinical forms of RBD associated with PD. Moreover, the percentage of time spent with muscle atonia during REM sleep was lower among patients with PD than among healthy control subjects (60.1% vs 93.2%; p = 0.003). CONCLUSIONS: RBD and REM sleep without atonia are frequent in PD as shown by PSG recordings.

Aged↗

PubMed2002

Age difference in heart rate changes associated with micro-arousals in humans.

OBJECTIVES: Heart rate (HR) is known to change in association to micro-arousals (MA) during sleep. The aim of the present study was to evaluate the effect of age on HR variations associated with MA. METHODS: Thirty-two healthy subjects underwent one night of polysomnographic recording. They were divided into two groups of 16 subjects according to age i.e. young (20-35 years) and middle-aged (50-65 years). The R-R intervals were calculated for 11 heart beats (10 intervals) before and 15 heart beats after the onset of MA. RESULTS: HR changes associated with MA were characterized by a tachycardia followed by a bradycardia in both young- and middle-aged subjects. However, middle-aged subjects showed a significant reduction in the amplitude of both tachycardia and bradycardia as compared to young subjects. CONCLUSIONS: This study revealed an age-related reduction in the amplitude of the HR changes associated with MA. These results may reflect a decline in parasympathetic functions and a higher risk of cardiovascular diseases with advancing age.

Adult↗

PubMed2001

Effects of afternoon "siesta" naps on sleep, alertness, performance, and circadian rhythms in the elderly.

STUDY OBJECTIVES: To determine the effects of a 90-minute afternoon nap regimen on nocturnal sleep, circadian rhythms, and evening alertness and performance levels in the healthy elderly. DESIGN AND SETTING: Nine healthy elderly subjects (4m, 5f, age range 74y-87y) each experienced both nap and no-nap conditions in two studies each lasting 17 days (14 at home, 3 in the laboratory). In the nap condition a 90-minute nap was enforced between 13:30 and 15:00 every day, in the no-nap condition daytime napping was prohibited, and activity encouraged in the 13:30-15:00 interval. The order of the two conditions was counterbalanced. PARTICIPANTS: N/A. INTERVENTIONS: N/A. MEASUREMENTS: Diary measures, pencil and paper alertness tests, and wrist actigraphy were used at home. In the 72 hour laboratory studies, these measures were augmented by polysomnographic sleep recording, continuous rectal temperature measurement, a daily evening single trial of a Multiple Sleep Latency Test (MSLT), and computerized tests of mood, activation and performance efficiency. RESULTS: By the second week in the "at home" study, an average of 58 minutes of sleep was reported per siesta nap; in the laboratory, polysomnography confirmed an average of 57 minutes of sleep per nap. When nap and no-nap conditions were compared, mixed effects on nocturnal sleep were observed. Diary measures indicated no significant difference in nocturnal sleep duration, but a significant increase (of 38 mins.) in 24-hour Total Sleep Time (TST) when nocturnal sleeps and naps were added together (p<0.025). The laboratory study revealed a decrease of 2.4% in nocturnal sleep efficiency in the nap condition (p<0.025), a reduction of nocturnal Total Sleep Time (TST) by 48 mins. in the nap condition (p<0.001) which resulted primarily from significantly earlier waketimes (p<0.005), but no reliable effects on Wake After Sleep Onset (WASO), delta sleep measures, or percent stages 1 & 2. Unlike the diary study, the laboratory study yielded no overall increase in 24-hour TST consequent upon the siesta nap regimen. The only measure of evening alertness or performance to show an improvement was sleep latency in a single-trial evening MSLT (nap: 15.6 mins., no nap: 11.5 mins., p<0.005). No significant change in circadian rhythm parameters was observed. CONCLUSIONS: Healthy seniors were able to adopt a napping regimen involving a 90-minute siesta nap each day between 13:30 and 15:00, achieving about one hour of actual sleep per nap. There were some negative consequences for nocturnal sleep in terms of reduced sleep efficiency and earlier waketimes, but also some positive consequences for objective evening performance and (in the diary study) 24-hour sleep totals. Subjective alertness measures and performance measures showed no reliable effects and circadian phase parameters appeared unchanged.

Aged↗

PubMed2001

Molecular genetics of ulcerative colitis-associated colon cancer in the interleukin 2- and beta(2)-microglobulin-deficient mouse.

Mice deficient in beta(2)-microglobulin and interleukin 2 (beta(2)m(null) x IL-2(null)) spontaneously develop colon cancer in the setting of chronic ulcerative colitis (UC). We investigated mutations of the Apc and p53 genes and microsatellite instability in colonic adenocarcinomas arising in this model. Mutations of the Apc and p53 genes in the regions corresponding to mutation hot spots in human colorectal cancer were determined by sequencing in 11 colonic adenocarcinomas. Microsatellite instability was determined in matched normal and neoplastic DNA at five loci. All 11 adenocarcinomas harbored Apc mutations. Of these 11 tumors, 5 harbored truncating mutations. A total of 67 Apc mutations were found in these 11 tumors; 59 were missense mutations, whereas 8 were frameshift or nonsense mutations. Six of the 11 adenocarcinomas harbored p53 mutations. A total of seven p53 mutations were found in these 11 tumors; all mutations were transitions, 4 of which were C:G-->T:A transitions occurring in codon 229 at cytosine-guanine dinucleotides. Nine adenocarcinomas exhibited microsatellite instability in at least one of the five loci examined; 1 tumor had microsatellite instability in two loci. Molecular genetics, as well as clinical features, of colon cancer in the beta(2)m(null) x IL-2(null) mice are similar to those of human UC-associated colorectal cancer. As such, this model appears to be an excellent animal model to study UC-associated colorectal carcinogenesis.

Adenocarcinoma↗

PubMed2001

Effect of iron supplementation on oxidative stress and intestinal inflammation in rats with acute colitis.

In this study, we investigated the effect of intraperitoneal iron dextran (100 mg/100 g body weight) on oxidative stress and intestinal inflammation in rats with acute colitis induced by 5% dextran sulfate sodium. In both colitis and healthy animals, disease activity index, crypt and inflammatory scores, colon length, plasma and colonic lipid peroxides, and plasma vitamins E, C, and retinol were assessed. The results showed that iron-supplemented groups had moderate iron deposition in the colonic submucosa and lamina propria. In the colitis group supplemented with iron, colon length was significantly shorter; disease activity index, crypt, and inflammatory scores and colonic lipid peroxides were significantly higher; and plasma alpha-tocopherol was significantly lower compared to the colitis group without iron supplementation. There was no intestinal inflammation and no significant increase in colonic lipid peroxides in healthy rats supplemented with iron. In conclusion, iron injection resulted in an increased oxidative stress and intestinal inflammation in rats with colitis but not in healthy rats.

Acute Disease↗

PubMed2001

Effect of oral iron supplementation on oxidative stress and colonic inflammation in rats with induced colitis.

BACKGROUND: Iron supplementation may increase disease activity in ulcerative colitis, possibly through the production of reactive oxygen species from the Fenton reaction. AIM: To assess the effects of two doses of oral iron on intestinal inflammation and oxidative stress in experimental colitis. METHODS: Colitis was induced in rats by giving 5% dextran sulphate sodium in drinking water for 7 days. First, using a 2 x 2 factorial design, rats with or without dextran sulphate sodium received the regular diet or a diet containing iron 3%/kg diet. Second, rats with dextran sulphate sodium-induced colitis were supplemented with iron 0.3%/kg diet and compared with rats on dextran sulphate sodium and regular diet. The body weight change, histological scores, colon length, rectal bleeding, plasma and colonic lipid peroxides, colonic glutathione peroxidase and plasma vitamin E and C were measured. Faecal analysis for haem and total, free and ethylenediaminetetra-acetic acid-chelatable iron was also performed. RESULTS: Iron 3% and iron 0.3% increased the activity of dextran sulphate sodium-induced colitis, as demonstrated by higher histological scores, heavier rectal bleeding and further shortening of the colon. This was associated with increased lipid peroxidation and decreased antioxidant vitamins. Faecal iron available to the Fenton reaction was increased in a dose-dependent manner. CONCLUSIONS: Iron supplementation taken orally enhanced the activity of dextran sulphate sodium-induced colitis and is associated with an increase in oxidative stress.

Administration, Oral↗

PubMed2001

Age-related modifications of NREM sleep EEG: from childhood to middle age.

This study investigated the modifications in non-rapid eye movement (NREM) sleep electroencephalogram (EEG) power in 54 subjects, from children to middle-aged adults. Spectral analyses were performed on 5 h of NREM sleep. A marked decrease of absolute slow-wave activity (SWA) was observed with increasing age; children had significantly more SWA than adolescents, young and middle-aged adults. The decline of SWA across the night seems to level off with increasing age, suggesting an age-related attenuation of homeostatic sleep pressure. Absolute theta power was higher for children compared with the other three groups, and adolescents had more theta power than young and middle-aged adults. In comparison to young and middle-aged adults, alpha power was higher for children and adolescents. Children and adolescents had more sigma power than middle-aged adults. Absolute beta power was higher for children than for the other age groups. Therefore, the major alterations of NREM sleep EEG occurring between childhood and middle age are not restricted to SWA, but encompassed the theta, alpha, sigma and beta frequency bands.

Adolescent↗

PubMed2001

Mapping as a method for analysing policy response in the management of health services.

Health services are susceptible to changes in health need, resource allocation, public-health debates and health policies. Service mapping is considered a useful tool for analysing complex issues, monitoring changes over time and facilitating change. It also enables one to describe pathways of care and the relationships between services. This article centres on two projects--a London-wide project 'Service networks for HIV Care' and a local survey 'Mapping of HIV-related services for illicit drug users'--and demonstrates the usefulness of mapping for both studies. Mapping of service networks allowed exploration of a variety of connections between treatment centres, and led to recommendations for a model of HIV service networks across London. The mapping of HIV-related services for illicit drug users confirmed that the service provision was balanced in time, space and target groups, but also identified gaps showing that services were not very successful in attracting women and members of ethnic minority groups. It is clear from both studies that mapping provides an overview of existing services, describing details of services, their target groups or links. It can assist to monitor changes over time, to reconfigure services according to need, and to target resources where need becomes apparent. Mapping exercises also can be useful in identifying new areas for collaboration and interagency work.

Community Health Planning↗

PubMed2001

The effects of age and gender on sleep EEG power spectral density in the middle years of life (ages 20-60 years old).

The effects of age and gender on sleep EEG power spectral density were assessed in a group of 100 subjects aged 20 to 60 years. We propose a new statistical strategy (mixed-model using fixed-knot regression splines) to analyze quantitative EEG measures. The effect of gender varied according to frequency, but no interactions emerged between age and gender, suggesting that the aging process does not differentially influence men and women. Women had higher power density than men in delta, theta, low alpha, and high spindle frequency range. The effect of age varied according to frequency and across the night. The decrease in power with age was not restricted to slow-wave activity, but also included theta and sigma activity. With increasing age, the attenuation over the night in power density between 1.25 and 8.00 Hz diminished, and the rise in power between 12.25 and 14.00 Hz across the night decreased. Increasing age was associated with higher power in the beta range. These results suggest that increasing age may be related to an attenuation of homeostatic sleep pressure and to an increase in cortical activation during sleep.

Adult↗

PubMed2000

Inducing jet-lag in older people: directional asymmetry.

Twenty healthy elderly subjects (12 female, 8 male; mean age 81 years, range 67-87 years) each experienced a 15-day time isolation protocol in which they lived individually in a special laboratory apartment in which sleep and circadian rhythm measures could be taken. There were two experiments: one (6 females, 4 males) involved a 6-h phase advance of the sleep/wake cycle, and the other (6 females, 4 males) a 6-h phase delay. Each started with 5 baseline days, immediately followed by the phase shift. The subject was then held to the phase shifted routine for the remainder of the study. Rectal temperatures were recorded minute-by-minute throughout the entire experiment and each night of sleep was recorded using polysomnography. A directional asymmetry in phase-shift effects was apparent, with significantly more sleep disruption and circadian rhythm amplitude disruption after the phase advance than after the phase delay. Sleep disruption was reflected in reduced time spent asleep, and in changed REM latency, which increased in the phase advance direction but decreased in the phase delay direction. Although the phase advance led to a significant increase in wakefulness in the first half of the night, the phase delay did not lead to an equivalent increase in wakefulness during the second half of the night. Examination of both raw and 'demasked' circadian rectal temperature rhythms confirmed that phase adjustment was slow in both directions, but was less slow (and more monotonic) after the phase delay than after the phase advance. Subjective alertness suffered more disruption after the phase advance than after the phase delay.

Aged↗

PubMed2000

Sleep and circadian phase characteristics of adolescent and young adult males in a naturalistic summertime condition.

Our aim was to compare the circadian phase characteristics of healthy adolescent and young adult males in a naturalistic summertime condition. A total of 19 adolescents (mean age 15.7 years) and 18 young adults (mean age 24.5 years) with no sleep problems took part in this study. Two-night polysomnographic (PSG) sleep recordings and 24h secretion patterns of urinary 6-sulfatoxymelatonin were monitored in all 37 subjects. Sleep-wake patterns were initially assessed at home using a standard sleep diary. Circadian assessment included the measure of dim light melatonin offset (DLMOff) and the morningness-eveningness (M/E) questionnaire. As expected, compared to young adults, adolescents habitually spent more nocturnal time in bed and spent more time (and percentage) in delta sleep. No difference was found between adolescents and young adults on multiple sleep latency test (MSLT) sleep onset latencies, M/E, melatonin secretion measures (24h total, nighttime, daytime, and night ratio), and DLMOff. For the subjects as a whole, correlational analyses revealed a significant association between the DLMOff and M/E and between both these phase markers and habitual bedtimes, habitual rising times, and melatonin secretion measures (daytime levels and the night ratio). No association was found between phase markers and daytime sleepiness or sleep consolidation parameters such as sleep efficiency or number of microarousals. These results together indicate that adolescents and young adults investigated during summertime showed similar circadian phase characteristics, and that, in these age groups, an evening phase preference is associated with a delayed melatonin secretion pattern and delayed habitual sleep patterns without a decrease in sleep consolidation or vigilance.

Adolescent↗

PubMed2000

Circadian rhythms of performance: new trends.

This brief review is concerned with how human performance efficiency changes as a function of time of day. It presents an overview of some of the research paradigms and conceptual models that have been used to investigate circadian performance rhythms. The influence of homeostatic and circadian processes on performance regulation is discussed. The review also briefly presents recent mathematical models of alertness that have been used to predict cognitive performance. Related topics such as interindividual differences and the postlunch dip are presented.

Affect↗

PubMed1999

Time course of narrow frequency bands in the waking EEG during sleep deprivation.

Electroencephalograms (EEGs) of 14 normal subjects were recorded every 2 h during 38 h constant routines. Adjacent narrow frequency bands (NFB) with similar temporal trends were grouped into frequency clusters. Clusters I (2.00-7.75 Hz) and III (11.00-14.75 Hz) exhibited similar time courses which may reflect both the duration of time awake and a circadian modulation. Cluster II (8.00-10.75 Hz) was characterized by a time course similar to the circadian modulation of core body temperature. Cluster V (18.00-24.75 Hz) was correlated with subjective sleepiness and may reflect the increasing effort made by subjects to perform the task as sleep deprivation lengthened. Various NFB in the waking EEG may reflect different physiological mechanisms underlying variations in vigilance states.

Adult↗

PubMed1999

Patient satisfaction with HIV service provision in NPMS hospitals: the development of a standard satisfaction questionnaire. NPMS Steering Group.

A self-completion satisfaction questionnaire evaluating the standard of care of HIV outpatient services was developed as part of the National Prospective Monitoring System on the Use, Cost and Outcome of HIV Service Provision in English Hospitals (NPMS). The questionnaire was designed in conjunction with service users and health care professionals, and piloted in three London and three non-London HIV clinics. In addition to testing alternative methods of administering the questionnaire, the pilot provided satisfaction scores on a variety of aspects of service provision for participating clinics. The questionnaire was completed by 548 respondents and was most effectively collected using a sealed box in the clinic waiting area. Mean satisfaction scores for the attitude and skills of staff members was 4.7 (95% CI 4.6-4.7) but satisfaction scores were significantly lower for the clinic environment with a mean of 4.1 (95% CI 4.1-4.2). Satisfaction scores did not differ significantly by gender, age, sexual orientation, ethnic group, employment status or severity of symptoms. London respondents were more satisfied with the clinic environment and seeing preferred members of staff than their non-London counterparts, however there were no other differences between clinics. The questionnaire functioned well in practice and provided meaningful and useful information for individual clinics as well as at aggregate level.

Acquired Immunodeficiency Syndrome↗

PubMed1999

Are age differences in sleep due to phase differences in the output of the circadian timing system?

Our aim was to evaluate whether age-related changes in the phase of the output of the circadian timing system (CTS) can explain age differences in habitual bedtime/wake time and in sleep consolidation parameters. Analyses focused on a group of healthy elderly people (older than 70 years) with no sleep problems and with similar subjective sleep quality as a young control group. The 2-week sleep diary data and 24h laboratory temperature recordings were examined for 70 subjects (22 young men [YM], 19 old men [OM], 29 old women [OW]). Polysomnographic (PSG) sleep data recorded during temperature data acquisition were also available for 62 subjects. These analyses made use of our recently developed technique to demask temperature rhythm data. As expected, compared to the young subjects, older subjects showed earlier habitual bedtime and wake time, more disturbed sleep, and a tendency for an earlier minimum of the circadian temperature rhythm. Despite sleep consolidation differences, the groups showed very similar habitual phase-angle differences (interval between the time occurrence of the fitted temperature minimum and habitual wake time). Both elderly and young subjects woke up on average 3 h after the temperature minimum. After controlling for the effects of age group, habitual bedtime and wake time were related to clock time phase of the circadian temperature rhythm, with an earlier phase associated with earlier habitual bedtime and wake time. None of the sleep consolidation parameters were linked to the temperature phase angle. In conclusion, sleep consolidation changes associated with healthy aging do not appear to be related to changes in the phase-angle difference between the output signal from the CTS and sleep.

Adult↗

PubMed1998

Rocuronium is the best non-depolarizing relaxant to prevent succinylcholine fasciculations and myalgia.

PURPOSE: To determine which non-depolarizing relaxant among d-tubocurarine, vecuronium, atracurium, mivacurium and rocuronium prevented muscular fasciculations and myalgia following succinylcholine. METHODS: In this double blind randomized study, 120 female patients scheduled for laparoscopic procedures were studied. They were divided into six groups of 20 according to the non-depolarizing pretreatment used: NaCl 0.9% (control), 0.05 mg.kg-1 d-tubocurarine, 0.01 mg.kg-1 vecuronium, 0.05 mg.kg-1 atracurium, 0.02 mg.kg-1 mivacurium and 0.06 mg.kg-1 rocuronium. Four minutes after the pretreatment, 1.5 mg.kg-1 succinylcholine was injected. Side effects of the pretreatment, the presence and magnitude of fasciculations, the ease of tracheal intubation, myalgia 1, 24 and 48 hr after surgery were observed. A Puritan Bennett Datex 221 NMT Relaxograph monitor was used to evaluate the neuromuscular block. RESULTS: Muscle fasciculations were observed in 19 of the 20 patients in the control group and in 3 of the 20 patients in the rocuronium group, the best of the pretreatments in that aspect. Four patients in the mivacurium group were unable to sustain more than four seconds head-lift after pretreatment (P < 0.05). Tracheal intubation conditions were better and the onset of block was faster and longer after succinylcholine in the control group (P < 0.05). Myalgias were present in 71% of the patients 24 hr postoperatively and the frequency was not different among the groups. CONCLUSION: Among the pretreatments tested, 0.06 mg.kg-1 rocuronium was the best to prevent muscular fasciculations following succinylcholine injection. In the population studied, pretreatment did not prevent postoperative myalgia. Succinylcholine 1.5 mg.kg-1 was more effective without a non-depolarizing pretreatment.

Adult↗

PubMed1998

A parallelism between human body temperature and performance independent of the endogenous circadian pacemaker.

A battery of performance tests involving manual dexterity, serial search, and verbal reasoning was given about seven times per day to 2 healthy young male subjects (22 and 25 years of age) involved in separate forced desynchrony studies, each involving several months of temporal isolation. In these studies, the period lengths (denoted T) of the imposed day lengths (sleep/wake and light/dark cycles) were 25.8 and 26.0 h for the 2 subjects. For each subject, the endogenous circadian pacemaker (ECP) failed to entrain to a period of T and instead free ran at a period length denoted tau (24.2 and 24.5 h). By educing performance rhythms (and rectal temperature rhythms) separately at tau and at T (after three complete beating cycles for the first subject and two complete beating cycles for the second subject), the hypothesis could be tested as to whether performance and temperature were parallel, both when educed at tau (indicating ECP influence) and when educed at T (indicating sleep/wake cycle influences). The hypothesis was consistently confirmed at tau and mostly confirmed at T. For most variables, when educed at T, both performance speed and body temperature showed an inverted V-shaped function, with a peak about 9 to 12 h after waking.

Adult↗

PubMed1997

Daytime sleep propensity after moderate circadian phase shifts induced with bright light exposure.

Moderate circadian phase shifts were induced by 3 days of bright light exposure, without changing the habitual sleep schedule. Daytime sleep propensity was evaluated with multiple sleep latency tests (MSLT) conducted before and after the light treatment. Phase shifts were estimated using the core body temperature rhythm recorded during constant routines. The subjects were divided into three groups according to the timing of the bright light exposure. Morning bright light exposure (Morning group) advanced the circadian phase by about 1.2 hours, evening bright light (Evening group) delayed the circadian phase by 1.6 hours on average; whereas, bright light administered in the afternoon (Afternoon group) did not change the circadian phase. After the light treatment, daytime sleep latencies decreased in the Evening and Afternoon groups, but did not change in the Morning group. Reduced sleep latencies in the Afternoon group probably reflect an increase in the manifest sleep tendency induced by the protocol itself. It is suggested that, in the presence of a high physiological sleep tendency, a moderate circadian phase delay may increase further daytime sleep propensity, whereas a moderate circadian phase advance may help to maintain daytime sleep propensity at a lower level.

Adolescent↗