Day-to-night time differences in the relationship between cardiorespiratory coordination and heart rate variability

Heart rate variability (HRV) and cardiorespiratory coordination, i.e. the temporal interplay between oscillations of heartbeat and respiration, reflect information related to the cardiovascular and autonomic nervous system. The purpose of this study was to investigate the relationship between spectral measures of HRV and measures of cardiorespiratory coordination. In 127 subjects from a normal population a 24 h Holter ECG was recorded. Average heart rate (HR) and the following HRV parameters were calculated: very low (VLF), low (LF) and high frequency (HF) oscillations and LF/HF. Cardiorespiratory coordination was quantified using average respiratory rate (RespR), the ratio of heart rate and respiratory rate (HRR), the phase coordination ratio (PCR) and the extent of cardiorespiratory coordination (PP). Pearson's correlation coefficient r was used to quantify the relationship between each pair of the variables across all subjects. HR and HRR correlated strongest during daytime (r = 0.89). LF/HF and PP showed a negative correlation to a reasonable degree (r = -0.69). During nighttime sleep these correlations decreased whereas the correlation between HRR and RespR (r = -0.47) as well as between HRR and PCR (r = 0.73) increased substantially. In conclusion, HRR and PCR deliver considerably different information compared to HRV measures whereas PP is partially linked reciprocally to LF/HF.

Locally generated particulate pollution and respiratory symptoms in young children

BACKGROUND: Particulate matter <10 mum (PM(10)) from fossil fuel combustion is associated with an increased prevalence of respiratory symptoms in children and adolescents. However, the effect of PM(10) on respiratory symptoms in young children is unclear. METHODS: The association between primary PM(10) (particles directly emitted from local sources) and the prevalence and incidence of respiratory symptoms was studied in a random sample cohort of 4400 Leicestershire children aged 1-5 years surveyed in 1998 and again in 2001. Annual exposure to primary PM(10) was calculated for the home address using the Airviro dispersion model and adjusted odds ratios (ORS) and 95% confidence intervals were calculated for each microg/m(3) increase. RESULTS: Exposure to primary PM(10) was associated with the prevalence of cough without a cold in both 1998 and 2001, with adjusted ORs of 1.21 (1.07 to 1.38) and 1.56 (1.32 to 1.84) respectively. For night time cough the ORs were 1.06 (0.94 to 1.19) and 1.25 (1.06 to 1.47), and for current wheeze 0.99 (0.88 to 1.12) and 1.28 (1.04 to 1.58), respectively. There was also an association between primary PM(10) and new onset symptoms. The ORs for incident symptoms were 1.62 (1.31 to 2.00) for cough without a cold and 1.42 (1.02 to 1.97) for wheeze. CONCLUSION: In young children there was a consistent association between locally generated primary PM(10) and the prevalence and incidence of cough without a cold and the incidence of wheeze which was independent of potential confounders.

Extrinsic causes of erosion. Behavioral factors

During and after an erosive challenge, behavioral factors play a role in modifying the extent of erosive tooth wear. The manner that dietary acids are introduced into the mouth (gulping, sipping, use of a straw) will affect how long the teeth are in contact with the erosive challenge. The frequency and duration of exposure to an erosive agent is of paramount importance. Night-time exposure (e.g. baby bottle-feeding) to erosive agents may be particularly destructive because of the absence of salivary flow. Health-conscious individuals tend to ingest acidic drinks and juices more frequently and tend to have higher than average oral hygiene. While good oral hygiene is of proven value in the prevention of periodontal disease and dental caries, frequent toothbrushing with abrasive oral hygiene products may enhance erosive tooth wear. Unhealthy lifestyles such as consumption of designer drugs, alcopops and alcohol abuse are other important behavioral factors.

Long-range correlations in rectal temperature fluctuations of healthy infants during maturation

BACKGROUND: Control of breathing, heart rate, and body temperature are interdependent in infants, where instabilities in thermoregulation can contribute to apneas or even life-threatening events. Identifying abnormalities in thermoregulation is particularly important in the first 6 months of life, where autonomic regulation undergoes critical development. Fluctuations in body temperature have been shown to be sensitive to maturational stage as well as system failure in critically ill patients. We thus aimed to investigate the existence of fractal-like long-range correlations, indicative of temperature control, in night time rectal temperature (T(rec)) patterns in maturing infants. METHODOLOGY/PRINCIPAL FINDINGS: We measured T(rec) fluctuations in infants every 4 weeks from 4 to 20 weeks of age and before and after immunization. Long-range correlations in the temperature series were quantified by the correlation exponent, alpha using detrended fluctuation analysis. The effects of maturation, room temperature, and immunization on the strength of correlation were investigated. We found that T(rec) fluctuations exhibit fractal long-range correlations with a mean (SD) alpha of 1.51 (0.11), indicating that T(rec) is regulated in a highly correlated and hence deterministic manner. A significant increase in alpha with age from 1.42 (0.07) at 4 weeks to 1.58 (0.04) at 20 weeks reflects a change in long-range correlation behavior with maturation towards a smoother and more deterministic temperature regulation, potentially due to the decrease in surface area to body weight ratio in the maturing infant. alpha was not associated with mean room temperature or influenced by immunization CONCLUSIONS: This study shows that the quantification of long-range correlations using alpha derived from detrended fluctuation analysis is an observer-independent tool which can distinguish developmental stages of night time T(rec) pattern in young infants, reflective of maturation of the autonomic system. Detrended fluctuation analysis may prove useful for characterizing thermoregulation in premature and other infants at risk for life-threatening events.

Reanalysis-driven climate simulation over CORDEX North America domain using the Canadian Regional Climate Model, version 5: model performance evaluation

The performance of reanalysis-driven Canadian Regional Climate Model, version 5 (CRCM5) in reproducing the present climate over the North American COordinated Regional climate Downscaling EXperiment domain for the 1989–2008 period has been assessed in comparison with several observation-based datasets. The model reproduces satisfactorily the near-surface temperature and precipitation characteristics over most part of North America. Coastal and mountainous zones remain problematic: a cold bias (2–6 °C) prevails over Rocky Mountains in summertime and all year-round over Mexico; winter precipitation in mountainous coastal regions is overestimated. The precipitation patterns related to the North American Monsoon are well reproduced, except on its northern limit. The spatial and temporal structure of the Great Plains Low-Level Jet is well reproduced by the model; however, the night-time precipitation maximum in the jet area is underestimated. The performance of CRCM5 was assessed against earlier CRCM versions and other RCMs. CRCM5 is shown to have been substantially improved compared to CRCM3 and CRCM4 in terms of seasonal mean statistics, and to be comparable to other modern RCMs.

Influence of manure scrapers on dairy cows in cubicle housing systems

Manure scrapers are widely used in dairy cow loose-housing systems. In order to evaluate the effects of the scrapers on the cows, we assessed their impact on the animals' cardiac activity, feeding behaviour, and the behavioural reactions of cows confronted with different types of scrapers. In part I of the study, we measured cardiac activity (mean R–R interval and RMSSD, a parameter of heart-rate variability) whilst observing the behaviour of 29 focal cows on three farms during situations with and without active manure scrapers. Lower RMSSD values were observed during scraping events while cows were either lying, standing or walking in the alleyway, standing completely in the lying cubicle, or standing half in the lying cubicle (P=0.03), but only tended to differ while directly confronted with the scraper (P=0.06). This indicates that dairy cows experienced at least some mild stress during manure-scraping events. In part II, the feeding behaviour of 12 cows on each of two farms was recorded by means of a jaw-movement sensor and compared between situations with the manure-scraping event following forage provision either within or outside the main daily feeding period (i.e. within 1 or after 2 h from forage provisioning, respectively). The duration of night-time feeding (P=0.049) and the number of feeding bouts (P=0.036) were higher when a manure-scraping event took place within the main daily feeding period, indicating that the cows' feeding behaviour had been disturbed. In part III, we observed the cows' behaviour on 15 farms during eight manure scraping events per farm, where each of five farms had one of three different scraper types. We assessed the cows' immediate reactions when confronted with the scraper. In addition, we recorded the number of animals present in the alleyways before and after the manure-scraping events. The more cows that were present in the alleyways before the scraping event, the lower the proportion of cows showing direct behavioural reactions both with (P=0.017) and without (P=0.028) scraper contact, and the higher the number of cows that left the alleyways (P<0.001). Scraper type did not influence the proportion of cows showing behavioural reactions. In conclusion, our results show that dairy cows perceive the manure-scraping event negatively in some situations, that feeding behaviour may be disturbed when scrapers are active during the main feeding period, and that cows avoid the scraper during crowded situations.

Cessation and resuming of alglucosidase alfa in Pompe disease: a retrospective analysis.

Enzyme replacement therapy (ERT) with recombinant human alglucosidase alfa (rhGAA) in late-onset Pompe disease is moderately effective. Little is known about the clinical course after treatment termination and the resumption of ERT. In Switzerland, rhGAA therapy for Pompe disease was temporarily withdrawn after the federal court judged that the treatment costs were greatly out of proportion compared to the benefits. Re-treatment was initiated after the therapy was finally licensed. We retrospectively analysed seven Pompe patients, who underwent cessation and resumption of ERT (median age 43 years). The delay from first symptoms to final diagnosis ranged from 4 to 20 years. The demographics, clinical characteristics, assessments with the 6-min walking test (6-MWT), the predicted forced vital capacity (FVC) and muscle strength were analysed. Before initiation of ERT, all patients suffered from proximal muscle weakness of the lower limbs; one was wheelchair-bound and two patients received night-time non-invasive ventilation. Initial treatment stabilised respiratory function in most patients and improved their walking performance. After treatment cessation, upright FVC declined in most and the 6-MWT declined in all patients. Two patients needed additional non-invasive ventilatory support. Twelve months after resuming ERT, the respiratory and walking capacity improved again in most patients. However, aside for one patient, none of the patients reached the same level of respiratory function or distance walked in 6 min, as at the time of ERT withdrawal. We conclude that cessation of ERT in Pompe disease causes a decline in clinical function and should be avoided. Resuming treatment only partially recovers respiratory function and walking capacity.

Classifying and mapping the urban transition in Vietnam

The urban transition almost always involves wrenching social adjustment as small agricultural communities are forced to adjust rapidly to industrial ways of life. Large-scale in-migration of young people, usually from poor regions, creates enormous demand and expectations for community and social services. One immediate problem planners face in approaching this challenge is how to define, differentiate, and map what is rural, urban, and transitional (i.e., peri-urban). This project established an urban classification for Vietnam by using national census and remote sensing data to identify and map the smallest administrative units for which data are collected as rural, peri-urban, urban, or urban core. We used both natural and human factors in the quantitative model: income from agriculture, land under agriculture and forests, houses with modern sanitation, and the Normalized Difference Vegetation Index. Model results suggest that in 2006, 71% of Vietnam's 10,891 communes were rural, 18% peri-urban, 3% urban, and 4% urban core. Of the communes our model classified as peri-urban, 61% were classified by the Vietnamese government as rural. More than 7% of Vietnam's land area can be classified as peri-urban and approximately 13% of its population (more than 11 million people) lives in peri-urban areas. We identified and mapped three types of peri-urban places: communes in the periphery of large towns and cities; communes along highways; and communes associated with provincial administration or home to industrial, energy, or natural resources projects (e.g., mining). We validated this classification based on ground observations, analyses of multi-temporal night-time lights data, and an examination of road networks. The model provides a method for rapidly assessing the rural–urban nature of places to assist planners in identifying rural areas undergoing rapid change with accompanying needs for investments in building, sanitation, road infrastructure, and government institutions.

Use of activity monitors for assessment of pruritus in an acute model of canine atopic dermatitis

BACKGROUND: We developed a canine model of acute atopic dermatitis to evaluate the potential of compounds to treat pruritus and skin lesions induced in Dermatophagoides farinae (Df)-sensitized dogs. HYPOTHESIS/OBJECTIVES: The aim was to investigate the effectiveness of long-term recording activity monitors to assess pruritus induced by allergen challenges. ANIMALS: Thirty-two Df-sensitized laboratory dogs. METHODS: In two blinded crossover studies, 28 Df-sensitized dogs were challenged on 3 days with a Df slurry applied to clipped abdominal skin. Dogs were treated with a positive control (prednisolone 1 mg/kg once daily for 5 days, starting 1 day before challenge) or left untreated; all were fitted with activity monitors. To confirm pruritus, a parallel study with four dogs was conducted, filming the dogs before and during challenge and assessing the film for pruritic behaviour. RESULTS: The activity of dogs treated with prednisolone was significantly lower between 00.00 and 03.00 h and between 03.00 and 06.00 h compared with untreated dogs (repeated-measures ANCOVA; P < 0.0001). To determine whether the recorded night-time activity corresponded to pruritic manifestations, we compared activity monitor and video recordings of four dogs for two periods (16.30-20.30 and 24.00-03.00 h) before and during a Df challenge. The correlation between night-time activity monitor activity and observed pruritic behaviour was highly significant (test of correlation coefficient versus zero: r = 0.57, P < 0.0001). CONCLUSIONS AND CLINICAL IMPORTANCE: Determination of night-time activity with activity monitors after allergen challenge appears to be an objective and practical way to assess pruritus in this experimental model of canine atopic dermatitis.

Associations of ambulatory blood pressure with urinary caffeine and caffeine metabolite excretions.

Intake of caffeinated beverages might be associated with reduced cardiovascular mortality possibly via the lowering of blood pressure. We estimated the association of ambulatory blood pressure with urinary caffeine and caffeine metabolites in a population-based sample. Families were randomly selected from the general population of Swiss cities. Ambulatory blood pressure monitoring was conducted using validated devices. Urinary caffeine, paraxanthine, theophylline, and theobromine excretions were measured in 24 hours urine using ultrahigh performance liquid chromatography tandem mass spectrometry. We used mixed models to explore the associations of urinary excretions with blood pressure although adjusting for major confounders. The 836 participants (48.9% men) included in this analysis had mean age of 47.8 and mean 24-hour systolic and diastolic blood pressure of 120.1 and 78.0 mm Hg. For each doubling of caffeine excretion, 24-hour and night-time systolic blood pressure decreased by 0.642 and 1.107 mm Hg (both P values <0.040). Similar inverse associations were observed for paraxanthine and theophylline. Adjusted night-time systolic blood pressure in the first (lowest), second, third, and fourth (highest) quartile of paraxanthine urinary excretions were 110.3, 107.3, 107.3, and 105.1 mm Hg, respectively (P trend <0.05). No associations of urinary excretions with diastolic blood pressure were generally found, and theobromine excretion was not associated with blood pressure. Anti-hypertensive therapy, diabetes mellitus, and alcohol consumption modify the association of caffeine urinary excretion with systolic blood pressure. Ambulatory systolic blood pressure was inversely associated with urinary excretions of caffeine and other caffeine metabolites. Our results are compatible with a potential protective effect of caffeine on blood pressure.

Off-Hour Admission and Outcomes in Patients with Acute Intracerebral Hemorrhage in the INTERACT2 Trial

BACKGROUND Conflicting data exist of an association between off-hour (weekend, holiday, or night-time) hospital admission and adverse outcome in intracerebral hemorrhage (ICH). We determined the association between off-hour admissions and poor clinical outcome, and of any differential effect of early intensive blood pressure (BP) lowering treatment between off- and on-hour admissions, among participants of the Intensive BP Reduction in Acute Cerebral Hemorrhage Trial (INTERACT2). METHODS Subsidiary analysis of INTERACT2, a multinational, multicenter, clinical trial of patients with spontaneous ICH with elevated systolic BP, randomly assigned to intensive (target systolic BP <140 mm Hg) or guideline-based (<180 mm Hg) BP management. Primary outcome was death or major disability (modified Rankin scale of 3-6) at 90 days. Off-hour admission was defined as night-time (4:30 p.m. to 8:30 a.m.) on weekdays, weekends (Saturday and Sunday), and public holidays in each participating country. RESULTS Of 2,794 patients with information on the primary outcome, 1,770 (63%) were admitted to study centers during off-hours. Off-hour admission was not associated with risk of poor outcome at 90 days (53% off-hour vs. 55% on-hour; p = 0.49), even after adjustment for comorbid risk factors (odds ratio 0.92; 95% CI 0.76-1.12). Consistency exists in the effects of intensive BP lowering between off- and on-hour admission (p = 0.85 for homogeneity). CONCLUSIONS Off-hour admission was not associated with increased risks of death or major disability among trial protocol participants with acute ICH. Intensive BP lowering can provide similar treatment effect irrespective of admission hours.

Social stressors at work and sleep quality on sunday night – The mediating role of psychological detachment

Purpose Recovery is a critical link between acute reactions to work-stressors and the development of health-impairments in the long run. Even though recovery is particularly necessary when recovery opportunities during work are insufficient, research on recovery during weekends, is still scarce. To fill this gap we tested, whether the inability to psychologically detach from work mediates the effect of social stressors at work on sleep quality on Sunday night. Design/Methodology Sixty full-time employees participated in the study. Daily assessment included diaries on psychological detachment and ambulatory actigraphy to assess psychophysiological indicators of sleep quality. Results Hierarchical regression analyses revealed social stressors at work to be related with psychological detachment and with several sleep quality parameters on Sunday night. Furthermore, psychological detachment from work mediated the effect of social stressors at work on sleep quality. Limitations Methodological considerations regarding the use of actigraphy data should be taken into account. Research/Practical Implications Our results show that social stressors at work may lower resources just before people get started into the new working week. Originality/Value This is the first study to show that social stressors at work are an antecedent of psychological detachment on Sunday evening and of objective sleep quality on Sunday.