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Biomedical subjects

F Carandente

Publications and source records attributed to F Carandente.

At least 37 records · Page 2Linked to original sources

[Circadian periodicity and stomach ulcer. An animal experiment model for the detection of rhythm factors in the genesis of civilization diseases].

Against the background of clinical experience attesting to the role of the circadian and circannual rhythm stage in gastric ulcerogenesis, animal experiments provide a model where by circadian stage and sex are both revealed as determinants of gastric ulcerogenesis. Experiments on the genetically mesor-hypertensive Okamoto rat demonstrate the critical interaction of multiple loads in ulcerogenesis, in keeping with a report by Glavin and Mikhail. While stimulation by single loads of a certain intensity--immobilization, food deprivation or cooling--did not regularly lead to the production of gastric ulcers, the combination of these same loads did so as a function of circadian state at the beginning of exposure time.

Animals↗

[Experimental research in the rat using chronobiologic methods simulating various work shifts of man].

Certain diseases associated rightly or wrongly with the exposure to excessive burdens, physical or emotional, have been claimed to be more frequent among shiftworkers, notably when work involved conditions with different interacting loads. As an example, one could focus upon apparent contradictions in the literature concerning shiftwork and ulcers: Doll and Jones report on a total of 4871 workers, either shiftworkers or not, that the incidence of ulcers was slightly lower, rather than higher, in shiftworkers. By contrast Duesberg and Weiss, comparing shiftworkers and employees working in a regular work day, found higher incidence of ulcers in shiftworkers. Bonnevie compared night-workers and day-workers and found that the ulcer incidence for the first type was 15% and for the second 5%. Moreover he points out that some individuals cannot cope with the shiftwork and show signs of gastric ulcer more often. Ulcerogenesis was investigated on a sperimental model (rats), following chronobiological methods. It was found that there is a statistically significant difference on the gastric sensibility between rats treated with multiple loads at first morning hours or evening; there is a large sensibility during morning hours that is during the rest period of rats.

Animals↗

[Aspects of humoral immunity in ulcerous colitis].

Various immunological indices, hitherto considered in isolation, were evaluated in a single group of 20 cases of ulcerous colitis. Immunofluorescence showed anticolon Ab in 3 cases (15%), whereas this features was absent in a control group. Antistomach, antithyroid and non-organ-specific Ab's (ANA, AMA, SMA) were equally incident in both groups. One caso is examined separately on account of its simultaneous presentation of human and rat antistomach and antithyroid and antismooth muscle Ab's. Reuma test, Waaler Roose reaction, L.E. phenomenon and test, and direct and indirect Coombs test results were negative in nearly all cases. Slight quantitative changes in serum proteins revealed by electrophoresis and immunodiffusion were indicative of inflammation with an immunitary tendency. The data are not sufficient to support the attribution of an autoimmunitary aetiology to ulcerous colitis, though simultaneous evaluation of reaction indices serves to strengthen this view.

Adolescent↗

Temporal aspects of glucocorticoid action and clinical implications.

Administration 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.

Adrenal Cortex↗

Heptadecapeptide ACTH 1-17: the first analogue in chronobiology.

The heptadecapeptide ACTH 1-17 is the analogue of corticotropin with beta-alanine in position 1, lysine instead of 17-arginine and a basic amide instead of 18 arginine-amide. These modifications give enhanced biological activity and longer duration of the action. Several researchers investigated the acute effect of the analogue after administration at different time points along the 24 h cycle, and discovered that glucocorticoid and mineralocorticoid responses are dissociated in terms of doses and timing. Cortisol and urinary 17 OH-CS rise more after morning injections whereas for aldosterone the maximum effect was noted at 14(00). The most interesting finding that concerns ACTH 1-17 is the chronizing effect. ACTH 1-17 can be a chronizer because its administration resets, for instance, the toleration to antimitotic drugs, to a more convenient time. At clinical level, a group of researchers studied, in some case correctly from a chronobiological point of view, the effect of the ACTH 1-17 on patients and on healthy subjects. It is useful to remember the concept of hierarchies of rhythms: each different periodic function is regulated or, better, intermodulated by a network of other periodic variables of the same organ or of other organs and systems. So the necessity of large samplings to evidentiate periodic phenomena, and the utility of investigating pertinent marker rhythms significantly correlated with those to be studied are evident. Autorhythmometry and automatic monitoring can help very much on this purpose.

Adrenocorticotropic Hormone↗

Chronobiometry with pocket calculators and computer systems.

Selected methods for the study of biologic time series are reviewed and their relative merits are discussed in the light of underlying assumptions. Their potential applications are exemplified in several fields of biology and medicine. The monitoring of environmental integrity, notably of pollution, is investigated. The need for specifying optimal sampling requirements is underlined. An individualized and time-qualified definition of health by the establishment of reference intervals is required for increasingly rational individualized program for the prevention and/or treatment of disease. With these reference intervals and rhythm characteristics available, one can better interpret with single samples or time series an increased risk of a certain disease or the inception of the disease. For all of these aims the monitoring of environmental and/or personal marker rhythms is essential--to obtain large data bases from which information can be more easily derived for monitoring personal health, to recognize risk as well as to diagnose disease early and to optimize treatment by timing according to rhythms.

Animals↗

Autorhythmometry: leads from single-sample medical check-ups toward a health science of time series.

Starting from the definition of health as given by the WHO, the authors emphasize that rhythms of biological variables should be taken into account if one is to arrive at a positive and individual definition of the concept of health. The evaluation of a single datum spot check of physiological functions does not permit to quantify health in dynamic terms whereas this may become possible when the rhythmic quality of these variables, according to a spectrum of characteristic frequencies, has been assessed. Rhythmometry provides for appropriate reference standards as regards both the population in general and the physical conditions of the same subject during certain spans in the (prospective) life history (spans selected according to consideration of risk and hence cost and benefit at a given age). The authors therefore stress the importance of rhythmometry, thanks to which the time course and other peculiarities of any biological phenomenon can be evaluated by obtaining serial measurements, objectively quantifying their characteristic features, and working out special models with the aid of computers. Of special interest, particularly for the evaluation of reference standards, is autorhythmometry (AR), to be used at least for certain variables. This is the method by which each subject studies himself, performing a certain number of measurements in the course of the day (or month or year) of his body temperature, blood pressure, cardiac rhythm, grip strength, etc. In AR, the subject takes an active part in the study of his condition of health and it has been shown that in the majority of cases these measurements are done with the utmost accuracy and precision, providing that the purpose of the operations to be performed has been adequately explained. The wide spread use of AR, during more or less extended periods in a lifetime, would permit the assessment of the normal situation for each individual and thus offer the possibility of diagnosing any disorder at its very beginning; it would thus be of great prophylactic value. The authors refer to the example of arterial blood pressure; widely different values for the normal levels can be found in the texts of different authors. They also show that a certain presure may be normal for a given subject at a certain time of day and be a sign of illness for another subject, or even for the same subject at a different ime. The authors suggest the introduction of AR in the curriculum of secondary schools and into the routine for outpatients and inpatients. This practice would increase the availability of information on public health at a lower cost. AR may be very usefully applied to chronotherapy: it is a well-known fact that there are rhythms of sensitivity and therefore rhythms of toxic as well as therapeutic effects for various drugs. These can be dove-tailed in such a way as to work out, for individual cases, a time for administration at which the therapeutic effect is at its maximum and the toxic one at its minimum...

Animals↗

Dynamics of nonprotein and protein sulfhydryl compounds in rat gastric mucosa: possible implication for cytoprotection and ulcerogenesis.

The hypothesis that nonprotein and protein sulfhydryls in gastric mucosa may play some role in the defensive and offensive processes of gastric epithelium was tested in this study in the intact rat gastric mucosa. Both sulfhydryl compounds presented statistically significant changes during the 24-hour day. The content of nonprotein sulfhydryls was less during the dark span than during the light span, while the circadian acrophase of protein sulfhydryls occurred during dark span. These results may offer a new interpretation of the greater vulnerability to ulcerogenic agents of the gastric mucosa of rats during their usual activity span.

Animals↗

Chronobiology meets the need for integration in a reductionist climate of biology and medicine.

One of us introduces a chronobiology course to students at the University of Milan, Italy, with a succinct statement that may well serve to summarize the foregoing 24 points. Its few lines distill the preceding details and formulate the raison d'être of Chronobiology: Chronobiology is: not only a science in its own right; not only a methodology; not only a new kind of statistical analysis; not just an aspect of biology, but a new way of invariably approaching any problem in biology, notably medicine.

Animals↗

Rhythms in the ovulatory cycle. 3rd: Cortisol and dehydroepiandrosterone sulphate (DHEA-S).

The circadian profiles of cortisol and dehydroepiandrosterone sulphate (DHEA-S) were analyzed in a homogeneous group of 15 young normally cycling women, at 4 times of the menstrual cycle: early follicular (EF), late follicular (LF), early luteal (EL) and late luteal (LL) stages. The circatrigintan variations of the same hormones were also evaluated. Population-mean cosinor analysis allowed the demonstration of a highly significant circadian periodicity for both variables in any of the 4 stages of the menstrual cycle; on the other hand, the same computation failed to demonstrate a significant circatrigintan periodicity. In each of the stages considered, the circadian acrophase of DHEA-S was delayed in comparison to that of cortisol, being located in the early afternoon hours. The demonstration of a clear-cut circadian oscillation in serum DHEA-S prompts studies on possible chrono-abnormalities of the steroid production in women with hyperandrogenic diseases.

Adult↗