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Biomedical subjects

A Cagnacci

Publications and source records attributed to A Cagnacci.

At least 37 records · Page 2Linked to original sources
PubMed1999

Effect of ovarian suppression on glucose metabolism of young lean women with and without ovarian hyperandrogenism.

Gonadal steroids are believed to influence glucose metabolism, oestrogens inducing an improvement and androgens or progestins a deterioration. At baseline and after 3 months of ovarian suppression with a gonadotrophin-releasing hormone analogue (GnRHa: goserelin depot 3.75 mg/28 days), glucose metabolism was evaluated in eight lean women affected by ovarian hyperandrogenism (PCOS) and six age-weight-matched non-hyperandrogenic women (controls) by using both an oral glucose tolerance test (75 g; OGTT) and the minimal model method. The latter method allows calculation of peripheral insulin sensitivity (Si) and glucose dependent glucose utilization (Sg). In PCOS, higher fasting concentrations (P < 0.05) of insulin and C-peptide, and lower Sg (P < 0.05) and Si (P < 0.01) were found. GnRHa did not significantly modify glucose metabolism of controls, while in women with PCOS it decreased fasting glucose (P < 0.05) and significantly increased Si (P < 0.03) up to control values. The present data indicate that strong suppression of ovarian activity improves Si in lean women with PCOS, while it is without relevant effects on glucose metabolism of non-hyperandrogenic women.

Adult↗
PubMed1999

Physiological doses of estradiol decrease nocturnal blood pressure in normotensive postmenopausal women.

The effect of a 2-mo treatment with transdermal estradiol (50 microgram/day) versus placebo on 24 h of blood pressure rhythm was investigated in 18 normotensive healthy postmenopausal women. Whereas daytime blood pressure was not modified, nighttime blood pressure was reduced by estradiol. Estradiol magnified the nocturnal decrement of systolic (14.3 +/- 7.2 vs. 9.8 +/- 6.7 mmHg, P = 0. 0033), diastolic (11.6 +/- 5.0 vs. 7.5 +/- 7.3 mmHg, P = 0.028), and mean (10.8 +/- 5.6 vs. 7.2 +/- 4.5 mmHg, P = 0.011) blood pressure. As a consequence, the 24-h rhythm of mean blood pressure was restored in 50% of the subjects (P = 0.045) in whom it was absent and was amplified in the remaining 50% of the subjects. Body mass index was an independent determinant of blood pressure values being directly related to the amplitude of the 24-h mean blood pressure rhythm (r2 = 0.38; P = 0.0067). In normotensive postmenopausal women, physiological doses of estradiol amplify the nocturnal decline of blood pressure.

Blood Pressure↗
PubMed1999

Oral contraceptives and vascular reactivity of great vessels in women.

Blood pressure and great vessel vascular reactivity, evaluated by color Doppler ultrasound, were investigated in users of third-generation oral contraceptives (n = 18) compared to non-users, who were studied either in the follicular (n = 8) or in the luteal (n = 10) phase of the menstrual cycle. Blood pressure measured at rest in the supine position, evaluated both in the follicular phase and in the luteal phase, was similar between oral contraceptive users and non-users. The pulsatility index (an indirect index of resistance to blood flow) of both the internal carotid artery and the axillary artery was similar in control women studied in the follicular phase and in the luteal phase. By contrast, in users of oral contraceptives, pulsatility index values of the internal carotid artery tended to be higher, whilst those of the axillary artery were significantly higher, than those of women in either the follicular phase (p < 0.01) or the luteal phase (p < 0.025). In conclusion, new third-generation oral contraceptives do not have a significant impact on blood pressure control, but still tend to increase vascular resistance to blood flow, particularly in areas more involved in the regulation of blood pressure, for example the axillary artery.

Adult↗
PubMed1998

Diurnal rhythms of labor and delivery in women: modulation by parity and seasons.

OBJECTIVES: Our purpose was to evaluate in women the diurnal (24 hour) rhythms of the onset of labor and time of delivery and their modulation by parity and seasons. STUDY DESIGN: A retrospective analysis was performed on 15,910 at term deliveries of single fetuses with noninduced labor. RESULTS: A diurnal rhythm of labor onset, with peak frequency at 8 PM and 9 AM was observed in nulliparous women but not in multiparous women. No diurnal rhythm of labor length was detectable. A diurnal rhythm of delivery, with peak values at 2 PM was evident in nulliparous but not in multiparous women. In nulliparous women the two acrophases of the diurnal rhythm of labor onset were closer in summer (10 hours) than in winter (13 hours). The acrophase of the diurnal rhythm of delivery progressively shifted to earlier hours from winter (5 PM) to summer (1 PM). CONCLUSIONS: These data show the attenuation of the diurnal rhythms of labor and delivery in multiparous women and their modulation by seasons.

Circadian Rhythm↗
PubMed1998

Effect of desogestrel-containing oral contraceptives on vascular reactivity and catecholamine levels.

The modifications induced by new oral contraceptives (OC) on blood pressure, great vessel vascular reactivity by color Doppler, and catecholamine levels were investigated. Young healthy women not taking OC (n = 22; controls) or receiving, for > or = 6 months, OC containing desogestrel with either 30 micrograms (n = 14) or 20 micrograms of EE (n = 8) were enrolled. Blood pressure measured at rest in supine position was similar between controls and OC users. The pulsatility index (PI), an indirect index of resistance to blood flow, of axillary artery was significantly higher (p < 0.05) in 30 micrograms than in 20 micrograms EE OC users or controls. A similar trend, albeit not significant, was observed for the internal carotid artery PI. Norepinephrine (p < 0.01) and dopamine (p < 0.05) but not epinephrine levels, were lower in 30 micrograms EE OC users than in 20 micrograms EE OC users or controls. Thus, both 20 micrograms and 30 micrograms EE OC had no negative effect on blood pressure, but the 30 micrograms EE OC tended to increase great vessel resistance to blood flow, independently of catecholamine levels.

Adult↗
PubMed1998

Influences of melatonin administration on the circulation of women.

The cardiovascular effects induced by the daytime administration of melatonin (1 mg) were compared with those of placebo in 17 young, healthy, early follicular-phase women. Compared with placebo, the administration of melatonin modified, within 90 min, the pulsatility index (PI), evaluated by color Doppler ultrasound, of the internal carotid artery, abdominal aorta, and axillary artery. The effect was linearly related to baseline PI, higher baseline PI being associated with greater PI declines. Melatonin administration significantly decreased mean PI of internal carotid artery (P < 0.02), systolic and diastolic blood pressure (P < 0.01), and norepinephrine levels evaluated after 5 min of standing position (P < 0.02). Heart rate and supine catecholamine levels were not modified. These data indicate that in young, healthy women the administration of 1 mg of melatonin greatly influences artery blood flow, decreases blood pressure, and blunts noradrenergic activation. Clinical implications of present data are worthy to be fully explored.

Adult↗
PubMed1997

The effect of transdermal 17-beta-estradiol on glucose metabolism of postmenopausal women is evident during the oral but not the intravenous glucose administration.

OBJECTIVES: To evaluate the effect of transdermal 17-beta-estradiol (50 micrograms/day) on glucose metabolism of postmenopausal women. STUDY DESIGN: A frequently sampled intravenous glucose tolerance test (FSIGT), to calculate insulin sensitivity (SI) and peripheral glucose utilization independent of insulin (SG), and an oral glucose tolerance test (75 g; OGTT), were performed in nine postmenopausal women prior to, and after 2 months of, treatment. RESULTS: Estradiol decreased insulin and increased the C-peptide/insulin ratio both during fasting (P < 0.02) and OGTT (insulin levels, P < 0.01; C-peptide/insulin ratio, P < 0.05), but not FSIGT. Glucose levels, C-peptide levels, SI and SG were not affected. CONCLUSIONS: In spite of unmodified SI, the reduction of insulin levels and the increase of the C-peptide/insulin ratio, observed during fasting and OGTT, support a beneficial effect of estradiol on glucose metabolism. This effect probably requires the interplay of estradiol with gastrointestinal factors.

Administration, Cutaneous↗
PubMed1997

Regulation of the 24-hour rhythm of body temperature in menstrual cycles with spontaneous and gonadotropin-induced ovulation.

OBJECTIVE: To investigate the relation between gonadal steroids and the 24-hour body temperature rhythm. PATIENT(S): Nineteen normally cycling women. DESIGN: Controlled clinical study in volunteer women. SETTING: Clinical hospital. INTERVENTION(S): Eleven women were studied in the early follicular and luteal menstrual phases of cycles with spontaneous ovulation, and 8 women were studied in the early follicular, preovulatory, and luteal phases of cycles with multiple follicular development. MAIN OUTCOME MEASURE(S): Starting at 5:00 P.M., intravaginal body temperature was monitored continuously for 24 hours and its values were related to E2 and P levels. RESULT(S): Twenty-four-hour body temperature rhythm parameters were related to the P:E2 ratio. Very low P:E2 ratios in the preovulatory phase were associated with a reduced 24-hour mean and an elevated body temperature rhythm amplitude. The progressive increase in the P:E2 ratio in the early follicular and luteal phases was associated with an increase in the 24-hour mean body temperature and a decrease in the rhythm amplitude. Body temperature differences between the luteal and early follicular phases were less pronounced in cycles with multiple follicular development. CONCLUSION(S): A woman's body temperature is related to her P:E2 ratio. Even in the presence of elevated P values, alterations of this ratio may influence negatively the postovulatory rise in body temperature.

Adult↗
PubMed1997

Potentially beneficial cardiovascular effects of melatonin administration in women.

The cardiovascular effects induced by the daytime administration of melatonin (1 mg) were compared to those of placebo in 12 young women. In order to eliminate cardiovascular effects due to fluctuating endogenous sex steroids, all women were taking a fixed dose of monophasic contraceptive pill. In comparison to placebo, the administration of melatonin reduced, within 90 min, the pulsatility index of the internal carotid artery, evaluated by color Doppler ultrasound (P < 0.01), as well as both systolic and diastolic blood pressure evaluated in supine position (P < 0.01). Supine catecholamine levels were not significantly modified, but norepinephrine levels evaluated after 5 min of standing position were significantly reduced (P < 0.02). These data suggest that in women the administration of 1 mg of melatonin may exert beneficial effects on blood vessels.

Adult↗
PubMed1997

Melatonin enhances cortisol levels in aged women: reversible by estrogens.

The administration of melatonin increases cortisol levels in postmenopausal women. Aging and hypoestrogenism are believed to impair the regulation of the hypothalamo-pituitary-adrenal axis and may participate in the determination of this altered response. In this study the implications of hypoestrogenism were tested. Seven postmenopausal women were studied. At 08.00 hr for 2 consecutive days, each woman received randomly and in a double blind fashion a pill of placebo or melatonin (100 mg). Serum melatonin and cortisol levels were evaluated at 20 min intervals, for 48 hr. Measurements were performed in the same subjects both during no estrogen supplementation and at least two cycles of conjugated estrogens administration (0.625 mg/day). During estrogen supplementation, postmenopausal women showed slightly lower cortisol levels at lunch and early night (20.00-01.00 hr). The onset of the nocturnal melatonin rise was not modified, but that of cortisol was delayed of about 60 min (P < 0.02). The administration of melatonin elicited a marked increase in daytime cortisol levels in postmenopausal women (P < 0.02), but this stimulus completely disappeared during estrogen administration. Mean nighttime (20.00-08.00 hr) cortisol levels were not modified by daytime administration of melatonin. The present data reveal that in aged postmenopausal women, reversal of hypoestrogenism, resulting from supplemental estrogens, may improve the regulation of the hypothalamopituitary-adrenal axis.

Aging↗
PubMed1997

Contemporaneous melatonin administration modifies the circadian response to nocturnal bright light stimuli.

We investigated whether the contemporaneous administration of melatonin can modify circadian phase shifts induced by bright light stimuli. After a baseline evaluation, 10 women were exposed for three consecutive nights to a 4-h bright light stimulus (>3,000 lx) initiated at the time of the estimated core body temperature (BT(c)) nadir. Along with light, each woman orally received, randomly and in a double-blind fashion, placebo (n = 5) or melatonin (n = 5; 1 mg 30 min before and 0.75 mg 120 min after the start of light exposure). Daily rhythms were reevaluated at the end of treatment. Bright light phase advanced, by about 90-120 min, BT(c) (P < 0.01), cortisol (P < 0.05), and melatonin (P < 0.01) rhythms. Contemporaneous administration of melatonin antagonized the phase advances of the cortisol and BT(c) rhythms, as well as the melatonin peak and melatonin offset. The phase advance of the melatonin onset was instead enhanced (P < 0.05). Contemporaneous melatonin administration modifies the capability of light to induce circadian phase shifts.

Adult↗
PubMed1997

Homeostatic versus circadian effects of melatonin on core body temperature in humans.

Evidence obtained in animals has suggested a link of the pineal gland and its hormone melatonin with the regulation of core body temperature (CBT). Depending on the species considered, melatonin intervenes in generating seasonal rhythms of daily torpor and hibernation, in heat stress tolerance, and in setting the CBT set point. In humans, the circadian rhythms of melatonin is strictly associated with that of CBT, the nocturnal decline of CBT being inversely related to the rise of melatonin. Whereas there is inconsistent evidence for the suggestion that the decline of CBT may prompt the release of melatonin, conversely, stringent data indicate that melatonin decreases CBT. Administration of melatonin during the day, when it is not normally secreted, decreases CBT by about 0.3 to 0.4 degree C, and suppression of melatonin at night enhances CBT by about the same magnitude. Accordingly, the nocturnal rise of melatonin contributes to the circadian amplitude of CBT. The mechanisms through which melatonin decreases CBT are unclear. It is known that melatonin enhances heat loss, but a reduction of heat production cannot be excluded. Besides actions on peripheral vessels aimed to favor heat loss, it is likely that the effect of melatonin to reduce CBT is exerted mainly in the hypothalamus, where thermoregulatory centers are located. Recent observations have shown that the acute thermoregulatory effects induced by melatonin and bright light are independent of their circadian phase-shifting effects. The effect of melatonin ultimately brings a saving of energy and is reduced in at least two physiological situations: aging and the luteal menstrual phase. In both conditions, melatonin does not exert its CBT-lowering effects. Whereas in older women this effect may represent an age-related alteration, in the luteal phase this modification may represent a mechanism of keeping CBT higher at night to promote a better embryo implantation and survival.

Body Temperature↗
PubMed1997

Effect of tibolone on glucose and lipid metabolism in postmenopausal women.

The effect of tibolone, a new therapeutic agent for menopause, on glucose and lipid metabolism was investigated in 11 healthy postmenopausal women. At baseline and after 3 months of tibolone administration (2.5 mg/day), glucose metabolism was evaluated in each subject using both an oral glucose tolerance test (75 g) and the minimal model method of a frequently sampled intravenous glucose tolerance test. Frequently sampled intravenous glucose tolerance test allows the calculation of insulin sensitivity and peripheral glucose use independent of insulin. High-density lipoprotein-cholesterol, total cholesterol, apoprotein-A, and apoprotein-B measured in fasting conditions were not modified by tibolone, whereas triglycerides were reduced significantly (P < 0.01). Fasting levels of glucose were reduced significantly (P < 0.025), whereas those of insulin, C-peptide, and the C-peptide/insulin ratio were not modified. Glucose, insulin, C-peptide, and the C-peptide/insulin ratio responses to oral or iv glucose were not modified. Insulin sensitivity was inversely correlated to body mass index, and independent on that body mass index was significantly enhanced (P < 0.01). Glucose utilization independent of insulin was not modified. The present data indicate that tibolone does not negatively influence glucose metabolism and may indeed improve both the peripheral tissue sensitivity to insulin and the lipid profile.

Anabolic Agents↗
PubMed1997

Influences of melatonin on human circadian rhythms.

Administration of melatonin is useful in the treatment of desynchronized conditions. The mechanisms through which melatonin exerts its effect are not completely clear. Melatonin exerts direct effects on several biological functions, such as the regulation of body temperature, but there is no proof that these actions are important in the indirect regulation of main pacemaker activity. By contrast, it is very likely that melatonin exerts direct effects on circadian clocks, and that depending on the time of its administration/presence, it antagonizes or promotes the phase-shifting effects exerted by light. It is possible that melatonin regulates its own secretion and that its prolonged or shortened secretion in the period of the night-day transition is responsible for the lengthening or shortening, respectively, of the nocturnal melatonin rise. This possibility that needs to be confirmed by extensive studies may represent a physiological mechanism through which photoperiodic information is more rapidly and efficiently transformed by melatonin in a circadian signal to all the body.

Animals↗
PubMed1997

Oral contraceptives and bone metabolism.

In women, the bone metabolism is markedly influenced by gonadal steroids and by their fluctuations. Indeed, estrogens influence bone metabolism by influencing endocrine and paracrine functions involved in bone remodelling. In normally cycling women, the administration of oral contraceptives does not increase bone mineral density and does not induce deleterious effects on bone. In women with ovulatory disturbances, bone turnover is increased and bone mineral density is lower than in normally cycling women. In these cases, administration of oral contraceptives is capable of blocking increased bone loss and of restoring a normal bone mineral density. Similarly, in women treated with gonadotropin releasing hormone (GnRH) analogs, the concomitant administration of oral contraceptives completely antagonizes GnRH analog-induced bone loss. The progestogenic component of oral contraceptives seems to contribute to the protective effect of estrogens on bone. Oral contraceptives are safe for bone maintenance in normal adult women, and are indeed indicated to prevent postmenopausal osteoporosis in women with ovulatory disturbances.

Adolescent↗
PubMed1997

Biochemical aspects of hormonal contraception: effects on bone metabolism.

Both trabecular and cortical bone mineral content reduction physiologically occur during the premenopausal period and, overall, at the time of menopause. It is related to plasma estrogen fall. Several studies have examined the relationship between bone density and oral contraceptives (OCs), but their results disagree. The different results may be due to the small number of patients investigated, the different OC formulations, and to the multifactorial nature of the bone loss phenomenon. Furthermore, the use of different techniques and different sites for measuring the bone density may limit the interpretation and reproducibility of the reported findings. Our previous studies evidenced that: (1) in premenopausal (40-45 years) women (n = 26), OCs, over a period of 2 years, do not induce any change either in bone mineral density or in bone metabolism biochemical markers (osteocalcin, alkaline phosphatase, urinary hydroxyproline/creatinine ratio; and (2) independent from the therapy length, the premenopausal use of OCs does not modify the bone mineral loss in postmenopausal patients (n = 40). The present study compared, over a period of 36 months, in perimenopausal (46-53 years; follicle stimulating hormone < or = 35 mU/ml; estradiol < 50 pg/ml) women, the effect of OCs (n = 8) on bone metabolism. The results were compared with those of a matched control group (n = 9). In the treated group, a slight, though not significant, bone mass improvement was observed during the entire therapy period, whereas, in the control group, a continued and progressive bone mass loss was observed and a significant decrease was shown at the end of the observational period. Our data suggest that OCs have no significant effects on bone metabolism in women during their childbearing years. However, OCs may be beneficial in inhibiting bone reabsorption in pre- and postmenopause. Furthermore, the pill, also in virtue of its contraceptive effect, would be the first presidium in hormone therapy in the premenopause.

Alkaline Phosphatase↗