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Biomedical subjects

B Tarquini

Publications and source records attributed to B Tarquini.

At least 19 recordsLinked to original sources
PubMed1999

Genetic and environmental influences on human cord blood leptin concentration.

OBJECTIVE: To examine in a population sample of cord blood the time structure (chronome) of leptin, an adipocyte-derived hormone, and to assess any effect of a familial history of noninsulin-dependent diabetes mellitus and obesity, separately, on both the maternal and the paternal side. SUBJECTS AND METHODS: Leptin concentration was determined in cord blood from 93 infants. Effects of gender, gestational age, birth weight, maternal weight, familial antecedents of obesity and noninsulin-dependent diabetes mellitus, and circadian and about-yearly stage were assessed by linear regression and ANOVA. RESULTS: Cord blood leptin concentration is elevated in the presence of a family history of obesity on the paternal side, but not on the maternal side. Leptin concentrations are higher in spring and summer than in fall and are higher in infants born before noon. In keeping with earlier work, leptin concentration in cord blood correlates positively with birth weight and height and is higher in infants who are appropriate for or large for gestational age than in infants who are small for gestational age or born prematurely. DISCUSSION: Changes along the scales of the day and the seasons point to synchronizing environmental as well as genetic influence. An association of cord blood leptin concentration with obesity on the paternal side may help clarify the role of leptin in parental contributions to human obesity and may prompt focus on cholesterol metabolism.

Circadian Rhythm↗
PubMed1998

Endothelin-1 and Paget's bone disease: is there a link?

The abundance of endothelial cells in bone marrow and the proximity of these cells to osteoclasts and osteoblasts suggest a role for endothelin-1 (ET-1) on bone metabolism. In vitro, the direct contact with bone endothelial cells induces osteoclastic progenitors to differentiate into mature elements. Recently it has been reported that ET-1 inhibits osteoclastic bone resorption and cell mobility through a specific receptor on osteoclasts; other authors demonstrated that ET-1 exerts a mitogenic activity on osteoblast-like cells (MC3T3) by stimulating tyrosin phosphorylation. We measured ET-1 circulating levels in patients with active Paget's bone disease, a condition with accelerated bone turnover. For the study we recruited 11 patients with Paget's bone disease (5F, 6M; mean age 68.2 +/- 3.6) in the acute stage of the disease; 10 healthy subjects (7F, 3M; mean age 66.5 +/- 3.9) were also enrolled as controls. Plasma ET-1 levels were measured with RIA kits provided by Nichols Institute. Patients showed significantly (P < 0.01) higher ET-1 circulating levels than controls (6.35 +/- 1.9 versus 3.4 +/- 1.2 pg/ml) with a positive correlation (r = 0.63; P = 0.038) with serum alkaline phosphatase (ALP), but not with urinary hydroxyproline. The higher levels of ET-1 in our patients suggest a physiopathological role for this peptide in the disease and, could perhaps represent a new useful marker of Paget's bone disease activity.

Acute Disease↗
PubMed1998

[Melatonin: a popular hormone].

This contribution makes an attempt to critically reassess the impressive career of melatonin (MEL) from a stepchild of hormone research to a best-seller of drug marketing. Melatonin, the hormone of the pineal gland, provides temporal information on diurnal and seasonal variation to the body and brain and it is involved in the synchronization of many different aspects of circadian systems to the light-dark cycle. In addition to these receptor-mediated functions, MEL may act as a modulator of intracellular signal transduction to enhance or suppress the responses of many different cells to other incoming signals. Melatonin is also a potent scavenger of reactive oxygen species and may thus protect cells and tissues against radical-mediated damages. The production of MEL declines with increasing age, and circulating MEL levels are affected by certain pharmacological or physiological manipulations. Animal and cell culture experiments suggest that MEL may have beneficial effects on certain aspects of aging and age-associated diseases. Of particular interest in this respect are reports on the influence of MEL on the brain and the immune system. The sole sufficiently investigated indication in humans is the treatment of certain sleep disorders from the group of sleep-wake-rhythm disturbances. These manifest themselves by sleep time of the day, i.e. in shift workers, after flights across time zones and in some aged persons. Clinical studies need to be performed in order to identify possible side effects of long-term MEL treatment. Serious concerns are raised about the use of uncontrolled, impure, or partially degraded MEL preparations.

Adolescent↗
PubMed1997

Endothelin-1's chronome indicates diabetic and vascular disease chronorisk.

Plasma endothelin-1 was measured around the clock in 72 subjects. Cosinor methods were used to assess circadian and other recurrent variation and trends, that is, the time structure (chronome) of this peptide. Multifactorial analyses of variance and linear regressions assessed chronome alterations associated with different risk factors: diabetes, obesity, high cholesterol, high blood pressure, vascular disease, smoking, and age. The rhythm-adjusted mean (MESOR) of endothelin-1 is elevated in diabetes and vascular disease. Diabetes is also associated with a larger circadian amplitude. A circadian variation in a subgroup of low-risk subjects is modulated by components with both lower and higher frequency.

Adult↗
PubMed1997

About-half-weekly (circasemiseptan) component of the endothelin-1 (ET-1) chronome and vascular disease risk.

Plasma ET-1 was measured around the clock on different calendar dates in healthy subjects and in subjects with diabetes and/or with high blood pressure and/or a history of vascular complications (HVDR). A transverse approach, with each subject contributing a single 24-h mean, assessed any about-weekly or half-weekly variation in ET-1. A circasemiseptan component resolved by single cosinor for nondiabetic (but not for diabetic) HVDR subjects (p = 0.010) differs in its timing of overall high values (p < 0.050) from that found in healthy subjects (p = 0.006). The results are aligned with circasemiseptan patterns in other circulatory variables and morbidity/mortality statistics.

Adult↗
PubMed1995

Angiopathy affects circulating endothelin-1 levels in type 2 diabetic patients.

To evaluate the role of endothelin-1 (ET-1), a vasoconstrictor and mitogenic peptide synthesized by endothelial cells, on the endothelial dysfunction in non-insulin-dependent diabetic (type 2) patients, we have measured the circulating ET-1 levels in 25 patients with and without clinically evident vascular complications and in a control group. Circulating ET-1 levels were significantly higher in diabetic patients with angiopathy than in diabetics without angiopathy and in controls (7.02 +/- 2.9 pg/ml vs 4.4 +/- 1.1 pg/ml and 3.08 +/- 0.7 pg/ml, respectively; P < 0.001). No difference was demonstrated between diabetic patients without angiopathy and controls. These findings suggest that ET-1 may be a marker for arterial vascular disease only in patients with overt angiopathy. It is unclear whether it participates in the endothelial injury process or it is merely released from damaged endothelial cells.

Biomarkers↗
PubMed1994

Daytime circulating melatonin levels in smokers.

AIMS AND BACKGROUND: Melatonin secretion is required to be a potential inhibitor of the development and growth of tumors, and cigarette smoking is a well established risk factor for cancer at various sites. METHODS: Circulating melatonin levels of 20 smokers and 20 non smokers (controls), sampled at the same hour from awaking in order to obtain a comparable circadian synchronization, were compared. RESULTS: Our data showed higher melatonin circulating levels in smokers (17.44 +/- 1.8 pg/ml) than in nonsmokers (9.77 +/- 1.4 pg/ml). CONCLUSIONS: The causes, mechanism and meaning of this phenomenon are still unknown. The most attractive hypothesis considers higher melatonin levels in smokers as an attempt to counterbalance cellular growth stimulus, a natural "brake" mechanism to restrain the proliferation of normally differentiated tissues: smoke is a prominent risk factor for several different tumors.

Adult↗
PubMed1993

Amplifying effect of sumatriptan on noradrenaline venoconstriction in migraine patients.

The venoconstrictive activity of sumatriptan and its interaction with noradrenaline (NA)- and 5-hydroxytryptamine (5HT) venoconstriction was studied in vivo in the hand vein of migraineurs. Sumatriptan, injected at increasing doses into the vein, caused local venoconstriction after a 500 microgram dose, comparable to that induced by 0.5-1 micrograms of 5HT. This venoconstriction was completely inhibited by low doses of ketanserin (5 micrograms). Subcutaneous sumatriptan (6 mg) provoked a minor increase in vein tone, lasting less than 30 min. Non-venoconstrictive doses of sumatriptan (10-100 micrograms), injected in the hand vein, produced an amplification of NA-venoconstriction but not of 5HT-induced venoconstriction. A similar increased effect was displayed by subcutaneous sumatriptan (6 mg) for at least 1 h. Sumatriptan appears to cause peripheral venoconstriction only at high doses locally applied (in the hand vein), by acting on 5HT2 receptors. Clinical subcutaneous doses (6 mg) do not show significant venoconstrictive effects. The amplifying effect on NA venoconstriction, also caused by 5HT, ergotamine and dihydroergotamine in human cranial arteries, may be important in explaining the therapeutic action of sumatriptan in migraine attacks.

Adolescent↗
PubMed1993

Chronobiology in epidemiology and preventive medicine.

Many of the known cardiovascular risk factors, such as hormones, metabolic parameters, lifestyle, blood pressure, fibrinogenesis, fibrinolytic activity, etc., and also the reactivity of the organism to stimuli, are periodical and therefore require adequate measures at specific times in appropriate frequencies. The presence of circadian, circannual or other wide frequency rhythms may lead to contradiction in the evaluation of a potential risk factor. Chronobiological analysis shows fine differences within a "risk variable", defining some characters which may imply the alteration of a parameter only at certain times. Periodical risk factors may therefore be foreseen and sometimes prevented. Moreover, chronobiological approach may show another peculiar relation between risk factors; this is the so-called chronorisk. The convergence, in certain periods of time, of the phases of various risk factors, may strengthen their combined value. On the other hand, the phases of the protective factors, in the same period of time, may contribute to reduce or strengthen this combined value. From this point of view combined risk, apparently unimportant, appears highly increased, as compared with the normal homeostatic value. At equal levels of risk factors, different distribution and amplitude of the phases implies great differences in final combined risk values. Acute heart attack has a daily, seasonal and perhaps ultradian rhythm; other cardiological events, such as angina pectoris and sudden death, have circadian rhythms. Also cerebral vascular events have daily, seasonal, weekly and monthly variations. The periodical variations of acute vascular events and of the related risk factors, near and far, implies many complex interrelations in timing of biological structures, which are still perceived by the physician only as "noise".

Chronobiology Phenomena↗
PubMed1989

Chronobiology, growth hormone and healthy and malignant growth.

Chronobiology, the computer-aided science (logos) of life (bios) in time (chronos), provides novel concepts, tools and facts for those concerned with mitosis, growth and growth hormone (GH). GH concentrations in human plasma demonstrate a statistically significant circadian rhythm on a 6h as well as on a 24h rest-activity cycle. On a 24h routine of light (L) and darkness (D), alternating at 12h intervals, and in continuous D, circadian mitotic rhythms in mice persist as a feature of growth or regeneration. A circadian cell cycle commences with an increase in phospholipid labeling, followed by an increase in cytoplasmic RNA formation, preceding, in regular sequences, an increase in nuclear DNA formation and the next mitotic peak in those cells that are dividing in a growing or regenerating (reversibly "post-mitotic') rodent liver. About 5-day (presumably estral) and about 7-day (circaseptan) components as well as circadians are resolved as a spectrum of mitotic rhythms in rodent cornea. The effects of hormones such as GH or a synthetic ACTH analogue, ACTH 1-17, depend upon the circadian cell cycle stages when the agent is administered. No effect or statistically significant effect can be the result only of 1) the timing of a fixed dose of GH or 2) of the timing of the samples taken to investigate any effect. For both the timing of administration and the assessment of effects, a multifrequency spectrum of rhythms, if taken into account, can provide (in lieu of a considerable and often formidable source of variation) a new critical dimension of growth and development.

Adolescent↗