Publications (22) View all
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Article: Tribute to Israel E. Ashkenazi 1934-2011.
Chronobiology International 08/2012; 29(7):795-8. · 4.03 Impact Factor -
Article: Rheumatoid Arthritis: Circadian Rhythms in Disease Activity, Signs and Symptoms, and Rationale for Chronotherapy with Corticosteroids and Other Medications.
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ABSTRACT: Biological processes and functions at all hierarchical levels are organized in time as biological rhythms of discrete periods. Circadian (24-hour) rhythms, which are of direct importance to clinical medicine, are orchestrated by a set of clock genes of the master brain clock situated in the suprachiasmatic nuclei of the hypothalamus plus numerous subservient peripheral cellular clocks of all tissues and organs. Circadian rhythms are kept in step with the surrounding physical and social milieu by periodic external time cues, the most important one being the 24-hour environmental light-dark cycle. The circadian time structure gives rise to predictable-in-time day-night patterns in morbid and mortal events plus symptom occurrence and severity of common chronic conditions, including rheumatoid arthritis (RA). The circadian pattern of various cytokines and hormones in RA disease activity suggests a new treatment paradigm (i.e., chronotherapy-timing medications to 24-hour rhythms in disease pathophysiology) to improve desired outcomes. Since the 1950s, RA chronotherapy in the United States and Europe has involved several nonsteroid anti-inflammatory drugs (NSAIDs), certain disease modifying antirheumatic drugs (DMARDs), and various synthetic corticosteroid medications.Bulletin of the NYU hospital for joint diseases 01/2012; 70(1):3-10. -
Article: Acute exposure to 50-Hz magnetic fields increases interleukin-6 in young healthy men.
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ABSTRACT: Some epidemiologic studies have suggested that extremely low frequency magnetic fields might affect human health and, in particular, that the incidence of certain types of cancer might increase among individuals living or working in environments exposed to such fields. This study is part of a broad study we conducted in humans. The study presented here was designed to look for possible effects of acute exposure to 50-Hz magnetic fields (10 μT) on the interleukin 1 beta (IL-1β), interleukin 2 (IL-2), interleukin 6 (IL-6), interleukin-1 receptor antagonist (IL-1RA), and the interleukin-2 receptor (IL-2R) production. Thirty-two young men (20-30 years old) were divided into two groups (sham-exposed or control group and exposed group) of 16 subjects each. All subjects participated in two 24-h experiments to evaluate the effects of both continuous and intermittent (1 h "off" and 1 h "on" with the field switched "on" and "off" every 15 s) exposure to linearly polarized magnetic fields. The subjects were exposed to the magnetic field from 2300 to 0800 while recumbent. Blood samples were collected during each session at 11:00, 17:00, 22:00, 01:00, 04:00, 06:00, and 08:00. Results showed that exposure to 50-Hz magnetic fields (10 μT) significantly increases IL-6 when subjects were exposed to an intermittent magnetic field. However, no effect has been observed on interleukin IL-1β, IL-2, IL-1RA, and IL-2R.Journal of Clinical Immunology 06/2011; 31(6):1105-11. · 3.08 Impact Factor -
Article: Clinical Chronobiology and Chronotherapeutics with Applications to Asthma
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ABSTRACT: The concept of homeostasis (i.e., constancy of the milieu interne) has long dominated the teaching and practice of medicine. Concepts and findings from chronobiology, the scientific study of biological rhythms, challenge this construct. Biological processes and functions are not at all constant; rather, they are organized in time as rhythms with period lengths that range in duration from as short as a second or less to as long as a year. It is the body's circadian (24h) rhythms that have been researched most intensely. The peak and trough of these rhythms are ordered rather precisely in time to support the biological requirements of activity during the day and sleep at night. The timing of the peak and trough plus the magnitude of variation (amplitude) of physiological and biochemical functions during the 24h give rise to predictable-in-time, day-night patterns in the manifestation and exacerbation of many common medical conditions. Circadian rhythms also can influence the response of patients to diagnostic tests and therapeutic interventions according to their timing with reference to body rhythms. Rhythms in the pathophysiology of medical conditions and patient tolerance to medications constitute the basis for chronotherapeutics, the timing of treatment in relation to biological rhythm determinants as a means of optimizing beneficial effects and safety. The article discusses recent advances in medical chronobiology and chronotherapeutics and their relevance to clinical medicine in general and the management of asthma in particular. Indeed, since asthma is a disease that exhibits rather profound circadian rhythmicity, investigation of its pathophysiology and therapy necessitates a chronobiologic approach.07/2009; 16(5):539-563. -
Article: Working memory capacity is decreased in sleep-deprived internal medicine residents.
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ABSTRACT: Concerns about medical errors due to sleep deprivation during residency training led the Accreditation Council for Graduate Medical Education to mandate reductions in work schedules. Although call rotations with extended shifts continue, effects on resident sleep-wake times and working memory capacity (WMC) have not been investigated. The objective of this study was to measure effects of call rotations on sleep-wake times and WMC in internal medicine residents. During 2 months of an internal medicine training program adhering to ACGME work-hour restrictions (between April 2006 and June 2007), residents completed daily WMC tests, wore actigraphy watches, and logged their sleep hours. This observational study was conducted during a call month requiring 30-hour call rotations every fourth night, whereas the noncall month, which allowed sleep/wake cycle freedom, was used as the control. Sleep hours per night and WMC testing. Thirty-nine residents completing the study had less sleep per night during their call month (6.4 vs 7.3 h per night noncall, p < 0.001) and sleep per night varied from 3.7 to 10.1 hours. Call rotation caused greater self-assessed sleepiness and reduced WMC recall scores (-2.6/test, p < 0.05), and more math errors occurred when on call (+1.07/test, p < 0.04). Full recovery of WMC did not occur until the fourth day after call. On-call rotation on the first month had a confounding detrimental effect on WMC. A month of call rotations reduced overall sleep per night; sleep hours per night were variable, and WMC was adversely affected. Decreased WMC could explain impaired judgment during sleep deprivation, although clinical error rates were not evaluated.Journal of clinical sleep medicine: JCSM: official publication of the American Academy of Sleep Medicine 06/2009; 5(3):191-7. · 3.23 Impact Factor
