1,721,167 research outputs found
Sliding lengthening spectrograms assess familial adult-to-elderly human aging in the blood circulation
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Gradual, Not Abrupt Circadian Cardiovascular Rhythm Shift after a Transmeridian (Milan-Minneapolis) Flight
No full textCircaseptan (about 7 day) rhythm in human kidney allograft rejection in different geographic locations
No full textIs a birth month dependence of human longevity influenced by half yearly changes in geomagnetics?
Full text linkAbout-daily and about-yearly variations in organisms are commonly viewed as evolutionary adaptations to changes in the proximate environmental temperature and illumination. There is now ample evidence that a much broader time structure (chronome), long known to characterize the environment, is built into biological variables, from the level of an ecological niche revealed by demographic statistics to that of molecular genetics. While a molecular basis has been established for circadian rhythms, indirect evidence for some endogenicity had long been available by the persistence of rhythms with a period differing from the environmental cycle under constant conditions (free-running) (1, 2). Natural environmental factors have also been shown to play a critical role, notably in terms of synchronizing built-in rhythms (1-3). As reviewed elsewhere (4), non-photic as well as photic effects of the sun may play a role in shaping the element of multifrequency rhythms currently, and may have done so in the past, resulting in even broader chronomes with added elements of chaos and trends (4, 5). Non-photic signatures include, with the biological week (5), the about 10.5-year solar activity cycle, the about 21.0-year Hale bipolarity variation, and a prominent about half-year rhythm peaking at the equinoxes. This natural physical half-year characterizes various indices of geomagnetic activity (6-15) and may relate to the tilt angle of the earth's dipole axis toward and away from the sun, which reportedly is not constant according to Robert L. McPherron. It is particularly prominent when analyzed in Kp (5, 16, 17) by the population-mean cosinor method (18, 19)
Antimicrobial agents as biological response modifiers (BRM) and chronoimmunomodulation: an emerging relationship
No full textImmune defense mechanisms play an essential protective role against infections caused by a wide array of pathogenic microorganisms. Although the growing number of the available antimicrobial agents has certainly improved the overall clinical outcome of such infections, antimicrobial therapy not rarely fails whenever the host's immune function is depressed. On the other hand, recently introduced therapeutic and diagnostic procedures (antineoplastic chemotherapy causing severe neutropenia and mucositis; organ transplantation requiring conditioning regimens; the widespread use of intravascular catheters and prosthetic devices; administration of adrenal corticosteroids and/or other immunosuppressive agents) have resulted in an unprecedented number of immunocompromised hosts. In addition, a variety of antibiotics have been found to display adverse effects on specific and non-specific immune functions, thus further impairing the already depressed immune system of the host. Antibiotic-mediated immunomodulation hence is explored with the introduction of a third-generation cephalosporin, namely cefodizime (CDZ), which has been shown to possess immunostimulating properties in preliminary in vitro and ex vivo studies as well as in a few experimental animal models. A chronoimmunopharmacological approach to CDZ-induced immunomodulation has been started by ourselves. The study, which is still in progress, includes patients with multiple myeloma (MM), selective IgA deficiency and chronic uremia, and matched healthy subjects. A number of immunological parameters are being assessed on blood samples drawn every 6h in the 24-h span prior to CDZ administration (a single 2 g daily dose i.v. for 6 days to the patients and for 4 days to healthy subjects), and in the 24h following the last CDZ injection. Healthy subjects and patients are randomly assigned to two groups, depending on whether they are given the antibiotic at 0800 or at 1800. Although a full evaluation of the results will be reported elsewhere, the group of MM now includes 24 patients. A circadian stage-dependent chronoimmunomodulating effect has been unequivocally shown for the monocytic chemotactic responsiveness to CDZ in MM. Immunostimulating 'side-effects' suggest that CDZ should possibly be regarded as a prototype antimicrobial agent for patients with impaired immune functions. Conceivably, a better knowledge of such properties will help synthesize new antibiotics with specific immunomodulating effects
The Sphygmochron, a cardiovascular summary, illustrates rhythmometry for advanced technology
No full textZirkadian-Periodik und Magengeschwur. Ein tierexperimentelles Modell zum Nachweis von rhythmischen Faktoren in der Genese von Zivilisationskrankheiten
No full textTemporal aspects of glucocorticoid action and clinical implications
No full textAdministration of glucocorticoids is effective and necessary in various diseases, but the appearance of side effects may compromise its results. Timing as well as dosing designed to obtain, for the highest number of patients, maximal beneficial effects with minimal undesired effects, is particularly pertinent to long-term corticosteroid therapy, in view of the rhythms exhibited by the endogenous secretion of adrenal cortical and coordinating hormones, primarily ACTH. In experimental animals, properly-timed circadian treatment can be preferred to alternate-day treatment for avoiding certain side effects. To secure the desired effect each day rather than only on alternate days, a chronobiologically correct corticosteroid therapy seeks the best compromise between timing for most of the desired and least of the undesired effects. This was the aim in the design of a chronopluricorticoid drug, with the time specification on its label. The clinical use of this preparation allowed the inferential statistical demonstration of a rhythmic circadian organization maintained during therapy, while the pharmacological results gained were similar to those obtained by the conventional administration of larger doses of corticoids
Mesor-hypertension: hints by chronobiologists
No full textCircadian systems are intermodulated by networks of specialized neural, hormonal and cellular functions, with time structures that are interdependent. In cardiovascular pathophysiology, circadian and ultradian rhythms of clinical interest have been demonstrated. Cardiac output, heart rate, arterial pressure and blood volume are the best known. Systolic and diastolic blood pressure and heart rate have circadian patterns in health and therefore arterial pressure cannot be evaluated by a single measurement during a 24-h span. With correct monitoring for at least 48-h it is possible to detect the mesor-hypertension and the possible amplitude-hypertension that precedes the mesor-hypertension. Prolonged elevation of blood pressure can cause irreparable harm to sensitive tissues. To quantify the damage, the concept of hyperbaric impact has been introduced. This is a measure of the excess load exerted upon the arterial walls. Studies of the beta-blocker penbutolol with correct automatic monitoring have shown the persistence of the physiological circadian variation in the cardiovascular parameters during penbutolol administration. The so-called elimination of the circadian rhythm in blood pressure, which would not really be desirable, was not seen in any of our patients, whose cardiovascular parameters were monitored continuously, day and night, while taking penbutolol. The amplitudes of the rhythms were always prominent. A phase shift, a delay of about 100 degrees, was demonstrated in the heart rate of one 63-year-old mesor-normotensive woman
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