Twenty-four-hour pattern of operations-related injury occurrence and severity of off-site/on-call volunteer French firefighters.

We assessed the 24-h pattern of operations-related injuries (ORI) experienced by scheduled off-site/on-call French volunteer firefighters (VFF) through analysis of an archival database. Occurrence and severity - evaluated by number of lost work days (LWD) and total medical costs (TMC) - of ORI were explored in terms of risk ratios, respectively, number of ORI/number of service operations (RR), number of LWD/number of ORI (RS,) and TMC/number of ORI (RS). Additionally, the collective work performance of all involved VFF was measured in terms of the lag time (LT) between emergency call-center firefighter-answered communication for service of observer-presumed out-of-hospital cardiac arrest (OHCA) and departure of vehicle from fire station to render aid, designated LT.

Working Time Society consensus statements: Circadian time structure impacts vulnerability to xenobiotics-relevance to industrial toxicology and nonstandard work schedules.

The circadian time structure (CTS) has long been the subject of research in occupational medicine, but not to industrial toxicology, including methods of setting threshold limit values (TLVs) and employee biological monitoring. Numerous animal and human investigations document vulnerability to chemical, contagion, and other xenobiotics varies according to the circadian time of encounter. Permanent and rotating nightshift personnel are exposed to industrial contaminants in the same or higher concentration as dayshift personnel, and because of incomplete CTS adjustment to night work, contact with contaminants occurs during a different biological time than day workers.

Daily, weekly and annual patterns in children's accidental sport injuries.

Details of serious injuries to children ≤16 yrs. of age that necessitated urgent surgical intervention by the Department of Pediatric Surgery of the University Hospital of Lausanne, Switzerland were recorded into a database registry. Some 15 110 entries listed the precise time of injury, and 3114 (20.

Perspectives on the relevance of the circadian time structure to workplace threshold limit values and employee biological monitoring.

The circadian time structure (CTS) and its disruption by rotating and nightshift schedules relative to work performance, accident risk, and health/wellbeing have long been areas of occupational medicine research. Yet, there has been little exploration of the relevance of the CTS to setting short-term, time-weighted, and ceiling threshold limit values (TLVs); conducting employee biological monitoring (BM); and establishing normative reference biological exposure indices (BEIs). Numerous publications during the past six decades document the CTS substantially affects the disposition - absorption, distribution, metabolism, and elimination - and effects of medications.

Do night and around-the-clock firefighters' shift schedules induce deviation in tau from 24 hours of systolic and diastolic blood pressure circadian rhythms?

Systolic (S) and diastolic (D) blood pressures (BP) [SBP and DBP] are circadian rhythmic with period (τ) in healthy persons assumed to be maintained at 24.0h. We tested this assumption in a sample of 30 healthy career (mean >12 yrs) 30-to-46 yr-old male Caucasian French firefighters (FFs) categorized into three groups according to work schedule and duties: Group A - 12 FFs working 12h day, 12h night, and occasionally 24h shifts and whose primary duties are firefighting plus paramedical and road rescue services; Group B - 9 FFs working mostly 12h day and 12h night shifts and whose duties are answering incoming emergency calls and coordinating service vehicle dispatch from fire stations with Group A personnel; Group C - 9 day shift (09:00-17:00h) FFs charged with administrative tasks.

Circadian variation in anticonvulsant activity of valproic acid in mice.

Purpose: This study aims to investigate whether valproic acid (VPA) anticonvulsant activity varied according to circadian dosing-time in mice.

Methods: VPA was administered to mice at four circadian stages (1, 7, 13 and 19h after light onset, (HALO)). The controls received a saline injection followed by a s.

Disruption of adolescents' circadian clock: The vicious circle of media use, exposure to light at night, sleep loss and risk behaviors.

Although sleep is a key element in adolescent development, teens are spending increasing amounts of time online with health risks related to excessive use of electronic media (computers, smartphones, tablets, consoles…) negatively associated with daytime functioning and sleep outcomes. Adolescent sleep becomes irregular, shortened and delayed in relation with later sleep onset and early waking time due to early school starting times on weekdays which results in rhythm desynchronization and sleep loss. In addition, exposure of adolescents to the numerous electronic devices prior to bedtime has become a great concern because LEDs emit much more blue light than white incandescent bulbs and compact fluorescent bulbs and have therefore a greater impact on the biological clock.

Association between light at night, melatonin secretion, sleep deprivation, and the internal clock: Health impacts and mechanisms of circadian disruption.

Exposure to Artificial Light At Night (ALAN) results in a disruption of the circadian system, which is deleterious to health. In industrialized countries, 75% of the total workforce is estimated to have been involved in shift work and night work. Epidemiologic studies, mainly of nurses, have revealed an association between sustained night work and a 50-100% higher incidence of breast cancer.

Dosing-time dependent oxidative effects of an immunosuppressive drug "Mycophenolate Mofetil" on rat kidneys.

This study investigates whether the toxicity in kidneys as well as oxidative stress varied according to the dosing time of an immunosuppressive agent "mycophenolate mofetil (MMF)" in Wistar Rat. 300mg/kg of MMF was injected by intraperitonal at four different circadian stages (1, 7, 13 and 19h after light onset, HALO). Rats were sacrificed after 3days, and the kidneys were removed for determination of oxidative stress and histological analysis.

Seven-day human biological rhythms: An expedition in search of their origin, synchronization, functional advantage, adaptive value and clinical relevance.

This fact-finding expedition explores the perspectives and knowledge of the origin and functional relevance of the 7 d domain of the biological time structure, with special reference to human beings. These biological rhythms are displayed at various levels of organization in diverse species - from the unicellular sea algae of Acetabularia and Goniaulax to plants, insects, fish, birds and mammals, including man - under natural as well as artificial, i.e.

Circadian variation of isoniazid pharmacokinetics in mice.

Introduction: This study is designed to investigate whether the pharmacokinetics of the antituberculous agent isoniazid (INH) varied according to the circadian dosing-time.

Methods: A total of 168 male mice aged 10 weeks and synchronized for 3 weeks to 12h light and 12h dark were used. A single INH (100mg/kg) dose was administered by intraperitonal (i.

Circadian variation of cytotoxicity and genotoxicity induced by an immunosuppressive agent "Mycophenolate Mofetil" in rats.

Immunosuppressive drugs such as Mycophenolate Mofetil (MMF) are used to suppress the immune system activity in transplant patients and reduce the risk of organ rejection. The present study investigates whether the potential cytotoxicity and genotoxicity varied according to MMF dosing-time in Wistar Rat. A potentially toxic MMF dose (300 mg/kg) was acutely administered by the i.

Disruption of the circadian period of body temperature by the anesthetic propofol.

The circadian time structure of an organism can be desynchronized in a large number of instances, including the intake of specific drugs. We have previously found that propofol, which is a general anesthetic, induces a desynchronization of the circadian time structure in rats, with a 60-80 min significant phase advance of body temperature circadian rhythm. We thus deemed it worthwhile to examine whether this phase shift of body temperature was related to a modification of the circadian period Tau.

Circadian disruption: New clinical perspective of disease pathology and basis for chronotherapeutic intervention.

Biological processes are organized in time as innate rhythms defined by the period (τ), phase (peak [Φ] and trough time), amplitude (A, peak-trough difference) and mean level. The human time structure in its entirety is comprised of ultradian (τ < 20 h), circadian (20 h > τ < 28 h) and infradian (τ > 28 h) bioperiodicities. The circadian time structure (CTS) of human beings, which is more complicated than in lower animals, is orchestrated and staged by a brain central multioscillator system that includes a prominent pacemaker - the suprachiasmatic nuclei of the hypothalamus.

Blooming rhythms of cactus Cereus peruvianus with nocturnal peak at full moon during seasons of prolonged daytime photoperiod.

Cereus peruvianus (Peruvian apple cactus) is a large erect and thorny succulent cactus characterized by column-like (cereus [L]: column), that is, candle-shaped, appendages. For three successive years (1100 days), between early April and late November, we studied the flowering patterns of eight cacti growing in public gardens and rural areas of north and central Tunisia, far from nighttime artificial illumination, in relation to natural environmental light, temperature, relative humidity and precipitation parameters. Flower blooming was assessed nightly between 23:00 h and until at least 02:00 h, and additionally around-the-clock at ~1 h intervals for 30 consecutive days during the late summer of each year of study to quantify both nyctohemeral (day-night) and lunar patterns.

The full moon as a synchronizer of circa-monthly biological rhythms: Chronobiologic perspectives based on multidisciplinary naturalistic research.

Biological rhythmicity is presumed to be an advantageous genetic adaptation of fitness and survival value resulting from evolution of life forms in an environment that varies predictably-in-time during the 24 h, month, and year. The 24 h light/dark cycle is the prime synchronizer of circadian periodicities, and its modulation over the course of the year, in terms of daytime photoperiod length, is a prime synchronizer of circannual periodicities. Circadian and circannual rhythms have been the major research focus of most scientists.

Gastrointestinal toxicity of mycophenolate mofetil in rats: Effect of administration time.

This study investigates whether the intestinal toxicity of the immunosuppressive agent "mycophenolate mofetil (MMF)" varied according to the circadian dosing-time in rats. MMF (300 mg/kg) was acutely administered by i.p.

Circadian variation in murine hepatotoxicity to the antituberculosis agent «Isoniazide».

The circadian time is an important process affecting both pharmacokinetics and pharmacodynamics of drugs. Consequently, the desired and/or undesired effects vary according to the time of drug administration in the 24 h scale. This study investigates whether the toxicity in liver as well as oxidative stress varies according to the circadian dosing-time of isoniazid (INH) in mice.

Circadian-time dependent tolerance and haematological toxicity to isoniazid in murine.

Introduction: Isoniazid (INH) is a widely used drug in the prophylaxis and treatment of tuberculosis. In the present study, isoniazid (INH)-induced toxicity was investigated according to the dosing-time in the 24-h scale in mice.

Methods: Two studies were carried out on a total of 180 male Swiss mice synchronized for 3 weeks to 12-hour light (rest) and 12-hour dark (activity) cycle (L/D: 12/12).

Circadian variation of mycophenolate mofetil pharmacokinetics in rats.

The present work aims to investigate whether the pharmacokinetics of the active metabolite mycophenolic acid (MPA) varies according to the circadian dosing-time of mycophenolate mofetil (MMF). A total of 180 male Wistar rats aged 8 weeks and synchronized for 3 weeks to 12 h light and 12 h dark were used. A single dose of 200 mg/kg of MMF was administrated in rats by i.