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Biomedical subjects

F Bernardi

Publications and source records attributed to F Bernardi.

At least 73 records · Page 4Linked to original sources
PubMed2000

Effects of estradiol and raloxifene analog on brain, adrenal and serum allopregnanolone content in fertile and ovariectomized female rats.

Allopregnanolone is a neuroactive steroid synthesized in rat gonads, adrenal cortex, and central nervous system. It has been suggested that sex steroid hormones might influence allopregnanolone concentrations but no clear data have ever been reported. The aim of the present study was to investigate the effects of administration of 17beta-estradiol (17beta-E2), the raloxifene analog LY-117018 or their combination on allopregnanolone levels in fertile and ovariectomized (OVX) rats. Thirteen groups of 12 Wistar female rats each received either 17beta-E2 (0.1 or 1 microg/day) or LY-117018 (25, 250, and 1,250 microg/day), or 17beta-E2 1 microg/day plus LY-117018: 25, 250, and 1,250 microg/day for 14 days. The rats were then sacrificed and allopregnanolone content was assessed in the hypothalamus, hippocampus, pituitary, adrenals, and serum. Ovariectomy determined a significant decrease in allopregnanolone content in the hypothalamus, hippocampus, pituitary, and serum, while increasing it in the adrenals (p<0.01). In OVX rats, the administration of either 17beta-E2 or LY- 117018 restored ovariectomy-induced allopregnanolone changes. The administration of LY-117018 in addition to 17beta-E2 to OVX animals suppressed the increase in allopregnanolone levels determined by 17beta-E2 in the hippocampus, hypothalamus, and pituitary, but not in the adrenals and serum. In fertile rats, the administration of LY-117018 reproduced the effects of ovariectomy. This study shows that the raloxifene analog LY-117018 has an estrogen-like action on the central nervous system of OVX rats when administered alone, while it acts as an antiestrogen in the presence of 17beta-E2, both in OVX animals treated with 17beta-E2 and in fertile rats. A different effect was observed in the adrenal glands. The mechanism of action of this compound has still to be clarified.

Adrenal Glands↗
PubMed2000

Serum allopregnanolone levels in pregnant women: changes during pregnancy, at delivery, and in hypertensive patients.

Allopregnanolone is a neuroactive steroid measurable in peripheral circulation. The aim of the present study was to investigate the presence and the possible changes in serum allopregnanolone and progesterone levels in pregnant women during gestation, at delivery, and in patients with chronic hypertension, with or without superimposed preeclampsia. We also evaluated allopregnanolone in cord blood. Three groups of pregnant women were studied: 1) healthy controls followed longitudinally throughout gestation (n = 14); 2) at vaginal or cesarean delivery (n = 66); and 3) with chronic hypertension (n = 12), with (n = 7) or without (n = 5) superimposed preeclampsia. Allopregnanolone and progesterone levels were measured in maternal and cord serum by RIA. In healthy pregnant women, serum allopregnanolone and progesterone levels progressively increased throughout gestation. Whereas no changes were found at vaginal delivery, serum allopregnanolone and progesterone levels were significantly lower at delivery by emergency cesarean section (P < 0.01). Umbilical cord serum allopregnanolone and progesterone levels in emergency cesarean were significantly lower than those found at vaginal delivery (P < 0.01). Patients with chronic hypertension, with or without superimposed severe preeclampsia, showed serum allopregnanolone levels significantly higher than those of healthy women at the same gestational age (P < 0.01). In conclusion, maternal serum allopregnanolone levels increased during normal gestation were lower in women who underwent emergency cesarean and higher in patients with chronic hypertension, with or without preeclampsia. Because allopregnanolone is active on the central nervous system and in the control of systemic blood pressure, an involvement of this neurosteroid in the adaptive processes induced by pregnancy is suggested.

Adult↗
PubMed2000

Allopregnanolone concentrations and premenstrual syndrome.

OBJECTIVE: To evaluate basal allopregnanolone and progesterone in both phases of the menstrual cycle in women suffering from premenstrual syndrome (PMS) and their response to a GnRH test. DESIGN: We selected 56 women (28 patients with PMS and 28 controls) aged between 18 and 32 years. Blood samples were drawn in both follicular and phases. Twenty-eight women (14 patients with PMS and 14 controls) underwent a GnRH test in the luteal phase. METHODS: We evaluated allopregnanolone by RIA, using a specific antibody. Serum progesterone and oestradiol were determined using a commercially available RIA kit. RESULTS: Luteal phase allopregnanolone concentrations were significantly lower in patients with PMS than in controls. Progesterone concentrations were significantly lower in patients with PMS in both the follicular and the luteal phase. Serum oestradiol concentrations were in the normal range in both groups of women, although slightly greater in those with PMS. Allopregnanolone and progesterone responses to a GnRH test were significantly blunted in women with PMS. CONCLUSIONS: Diminished concentrations of allopregnanolone and progesterone, its precursor, and a blunted response to the GnRH test lead us to hypothesise that patients with PMS may suffer from an inadequate production of ovarian neuroactive steroids, especially in the luteal phase. This would lead to an impaired anxiolytic GABA(A)-mediated response in stressful physiological and psychological conditions, and may in part explain various psychoneuroendocrine symptoms that arise during PMS.

Adult↗
PubMed2000

Hypothalamic amenorrhea with normal body weight: ACTH, allopregnanolone and cortisol responses to corticotropin-releasing hormone test.

OBJECTIVE: Hypothalamic amenorrhea (HA) is a functional disorder caused by disturbances in gonadotropin-releasing hormone (GnRH) pulsatility. The mechanism by which stress alters GnRH release is not well known. Recently, the role of corticotropin-releasing hormone (CRH) and neurosteroids in the pathophysiology of HA has been considered. The aim of the present study was to explore further the role of the hypothalamic-pituitary-adrenal axis in HA. DESIGN: We included 8 patients (aged 23.16+/-1.72 years) suffering from hypothalamic stress-related amenorrhea with normal body weight and 8 age-matched healthy controls in the follicular phase of the menstrual cycle. METHODS: We measured basal serum levels of FSH, LH, and estradiol and evaluated ACTH, allopregnanolone and cortisol responses to CRH test in both HA patients and healthy women. RESULTS: Serum basal levels of FSH, LH, and estradiol as well as basal levels of allopregnanolone were significantly lower in HA patients than in controls (P<0.001) while basal ACTH and cortisol levels were significantly higher in amenorrheic patients with respect to controls (P<0.001). The response (area under the curve) of ACTH, allopregnanolone and cortisol to CRH was significantly lower in amenorrheic women compared with controls (P<0.001, P<0.05, P<0.05 respectively). CONCLUSIONS: In conclusion, women with HA, despite the high ACTH and cortisol levels and, therefore, hypothalamus-pituitary-adrenal axis hyperactivity, are characterized by low allopregnanolone basal levels, deriving from an impairment of both adrenal and ovarian synthesis. The blunted ACTH, allopregnanolone and cortisol responses to CRH indicate that, in hypothalamic amenorrhea, there is a reduced sensitivity and expression of CRH receptor. These results open new perspectives on the role of neurosteroids in the pathogenesis of hypothalamic amenorrhea.

Adrenocorticotropic Hormone↗
PubMed2000

Allopregnanolone and dehydroepiandrosterone response to corticotropin-releasing factor in patients suffering from Alzheimer's disease and vascular dementia.

OBJECTIVE: Neurosteroids have been suggested to be involved in the regulation of cognitive performances. A major neurosteroid gamma-aminobutyric acid (GABA) agonist is allopregnanolone: the main source of circulating allopregnanolone is the adrenal cortex. Studies indicated that a disturbance of the central regulation of the hypothalamic-pituitary-adrenocortical axis occurs in both senile (Alzheimer's disease: AD) and vascular dementia (VD). DESIGN: The aim of the present study was to evaluate the levels of circulating allopregnanolone, dehydroepiandrosterone (DHEA) and cortisol and their response to corticotropin-releasing factor (CRF) test in AD and VD. METHODS: Three groups of 12 subjects were included in the study: AD, VD and age-matched control subjects. CRF test was performed in all subjects and allopregnanolone, DHEA and cortisol levels were measured every 15min for 2h. RESULTS: Mean +/- s.e.m. allopregnanolone and DHEA basal levels were significantly lower in AD and VD than in controls, while cortisol levels were significantly higher than in controls (P<0.01). Allopregnanolone and DHEA levels increase in response to CRF test in all subjects but the area under curve (AUC) in patients was significantly lower than in controls (P<0.01). Cortisol secretion appeared to be very sensitive in response to CRF stimulation: in fact, cortisol response to CRF test in AD and VD subjects was higher (both as AUC and as % max increase) than in controls (P<0.01). CONCLUSIONS: The present study firstly showed that allopregnanolone levels are reduced both in AD and in VD and that dementia has a preserved stimulated response of allopregnanolone to CRF. Overall, however, the total response of allopregnanolone to CRF remains reduced in respect to controls. Further studies are necessary for a better understanding of the role of neurosteroids in the regulation of cognitive function.

Aged↗
PubMed2000

Cyclosporin A upregulates phospholipase C beta1 in fibroblasts from gingival overgrowth.

BACKGROUND: In an attempt to evaluate the influence of cyclosporin A (CsA) on fibroblast metabolism, the phospholipase C beta1, (PLC beta1) nuclear expression was evaluated in fibroblasts from heart transplantation patients treated with CsA who exhibited gingival overgrowth (GO) and from controls. METHODS: PLC beta1 was assessed by immunoblotting and immunocytochemistry means. RESULTS: Findings did not show any difference in terms of PLC beta1 expression between the 2 groups when fibroblasts were incubated in media without CsA, while the addition of CsA highly stimulated the fibroblasts from CsA-treated patients compared to controls. The abnormal fibroblastic response in CsA-treated patients was detected both in cells from enlarged gingival sites and in cells from clinically healthy gingival sites. CONCLUSIONS: These results do not explain whether the exaggerated reactivity to in vitro CsA is the consequence of a genetically transmitted susceptibility to CsA that identifies those subjects at risk for developing GO, or whether it is a secondary effect of the long-term in vivo exposure to CsA. However, the present data underline the lack of any close relationship between enhanced fibroblast activity and clinical signs of GO and support the hypothesis that some other factors, together with CsA, are involved in the pathogenesis of CsA-induced GO.

Adult↗
PubMed2000

Six-month oral dehydroepiandrosterone supplementation in early and late postmenopause.

The adrenal production of the delta 5-androgens, dehydroepiandrosterone (DHEA) and its sulfate ester dehydroepiandrosterone sulfate (DHEAS), declines linearly with aging. The evidence that DHEA or DHEAS administration may alleviate some of the problems related to aging has opened new perspectives for clinical research. The present study aims to investigate the effects of a 6-month DHEA supplementation in early and late postmenopausal women, with normal or overweight body mass index (BMI), on the level of circulating steroids, sex hormone binding globulin (SHBG), beta-endorphin and gonadotropins, and on the adrenal gland response to dexamethasone suppression and adrenocorticotropic hormone (ACTH) stimulation. Early postmenopausal women (50-55 years) both normal weight (BMI 20-24, n = 9) and overweight (BMI 26-30, n = 9) and late postmenopausal women (60-65 years) both of normal weight and overweight, were treated with oral DHEA (50 mg/day). Circulating DHEA, DHEAS, 17-OH pregnenolone, progesterone, 17-OH progesterone, allopregnenolone, androstenedione, testosterone, dihydrotestosterone, estrone, estradiol, SHBG, cortisol, luteinizing hormone, follicle stimulating hormone and beta-endorphin levels were evaluated monthly and a Kupperman score was performed. The product/precursor ratios of adrenal steroid levels were used to assess the relative activities of the adrenal cortex enzymes. Before and after 3 and 6 months of therapy, each women underwent an ACTH stimulating test (10 micrograms i.v. in bolus) after dexamethasone administration (0.5 mg p.o.) to evaluate the response of cortisol, DHEA, DHEAS, androstenedione, 17-OH pregnenolone, allopregnanolone, progesterone and 17-OH progesterone. The between-group differences observed before treatment disappeared during DHEA administration. Levels of 17-OH pregnenolone remained constant during the 6 months. Levels of DHEA, DHEAS, androstenedione, testosterone and dihydrotestosterone increased progressively from the first month of treatment. Levels of estradiol and estrone significantly increased after the first/second month of treatment. Levels of SHBG significantly decreased from the second month of treatment only in overweight late postmenopausal women, while the other groups showed constant levels. Progesterone levels remained constant in all groups, while 17-OH progesterone levels showed a slight but significant increase in all groups. Allopregnanolone and plasma beta-endorphin levels increased progressively and significantly in the four groups, reaching values three times higher than baseline. Levels of cortisol and gonadotropins progressively decreased in all groups. The product/precursor ratios of adrenal steroid levels at the sixth month were used to assess the relative activities of the adrenal cortex enzymes and were compared to those found before therapy. The 17,20-desmolase, sulfatase and/or sulfotransferase, 17,20-lyase and 5 alpha-reductase activities significantly increased, while the 3 beta-hydroxysteroid-oxidoreductase activity did not vary. On the contrary, the 11-hydroxylase and/or 21-hydroxylase activities showed a significant decrease after 6 months of treatment. In basal conditions, dexamethasone significantly suppressed all the adrenal steroids and this suppression was greater after 3 and 6 months of treatment for DHEA, DHEAS and allopregnanolone, while it remained unchanged for other steroids. Before treatment, ACTH stimulus induced a significant response in all parameters; after the treatment, it prompted a greater response in delta 5- and delta 4-androgens, progesterone and 17-OH progesterone, while cortisol responded less in both younger and older normal-weight women. The endometrial thickness did not show significant modifications in any of the groups of postmenopausal women during the 6 months of treatment. Treatment with DHEA was associated with a progressive improvement of the Kupperman score in all groups, with major effects on the vasomotor symptoms in

Administration, Oral↗
PubMed2000

Mutations in the R2 FV gene affect the ratio between the two FV isoforms in plasma.

Molecular genetics and biochemical studies were performed in homozygotes for the R2 allele (4070G) in the factor V gene, most of them affected by coronary artery disease. Novel polymorphisms (G642T, 156Ser; T1328C, 385Met/Thr), among which a functional candidate (A6755G, 2194Asp/Gly) located in the C2 domain of FV, were identified in the R2 gene. In chromatographic studies R2 FV appeared qualitatively identical to normal FV. However, a relative increase of the more thrombogenic and more glycosylated FV isoform (FV1) was observed in plasma of 2194Gly homozygotes (mean FV1/FV2 ratio 0.71, 95% CI 0.66-0.77) as compared to R2-free controls (0.37, 95% CI 0.34-0.40). We conclude that carriership of the R2 FV gene is associated with an imbalance between the two functionally different FV isoforms, and propose that genetically determined differential glycosylation of FV could represent a novel mechanism of thrombotic disease.

Aged↗
PubMed1999

GH, IGFBP-1, and IGFBP-3 response to oral glucose tolerance test in perimenopausal women: no influence of body mass index.

OBJECTIVES: an increasing interest is being focused on the role of the somatotropic axis in the modulation of body weight and fat distribution, particularly in climacteric women. The influence of the glycometabolic state on the somatotropic axis in postmenopausal and in obese subjects has not been investigated. The aim of the present study is to evaluate whether menopause and body mass index (BMI) affect the response of growth hormone (GH), insulin-like growth factor-binding protein-1 (IGFBP-1) and -3 (IGFBP-3) to the oral glucose tolerance test (OGTT). METHODS: the study included 24 women, aged 45-55 years, categorized into 4 groups, premenopausal pre-obese (BMI = 28.5 +/- 0.8 Kg/m2) and normal body weight (BMI = 22.2 +/-1.1 Kg/m2), and postmenopausal pre-obese and normal body weight. All women underwent: (1) a biophysical evaluation with determination of waist/hip ratio; (2) an assessment of fat and lean tissue mass and body fat distribution by total body DEXA; and to (3) an OGTT. RESULTS: in response to OGTT plasma GH levels significantly decreased in all groups, but the relative decrease was more prominent in the lean subjects. A significant decrease of IGFBP-1 levels in response to OGTT was observed in all women, regardless of menopausal age and BMI, while IGFBP-3 levels did not significantly change in either group. CONCLUSIONS: in conclusion, the impact of both BMI and menopausal condition on GH, IGFBP-1, and -3 response to OGTT is limited to a blunted GH response in overweight women compared with normally-weighing ones. These findings appear to rule out the hypothesis that a common glycometabolic derangement may affect both the modifications of body weight and of the somatotropic axis observed in perimenopausal women.

Body Composition↗
PubMed1999

Potyvirus helper component-proteinase self-interaction in the yeast two-hybrid system and delineation of the interaction domain involved.

Using the yeast two-hybrid system, a screen was performed for possible interactions between the proteins encoded by the 5' region of potyviral genomes [P1, helper component-proteinase (HC-Pro), and P3]. A positive self-interaction involving HC-Pro was detected with lettuce mosaic virus (LMV) and potato virus Y (PVY). The possibility of heterologous interaction between the HC-Pro of LMV and of PVY was also demonstrated. No interaction involving either the P1 or the P3 proteins was detected. A series of ordered deletions from either the N- or C-terminal end of the LMV HC-Pro was used to map the domain involved in interaction to the 72 N-terminal amino acids of the protein, a region known to be dispensable for virus viability but necessary for aphid transmission. A similar but less detailed analysis mapped the interacting domain to the N-terminal half of the PVY HC-Pro.

Binding Sites↗
PubMed1999

Menopause and the central nervous system: intervention options.

The central nervous system is an important target for sex steroid hormones. During the climateric period the rapid decline of gonadal steroids causes neuroendocrine changes in different areas of the brain. The failure of gonadal hormone production brings specific symptoms due to the central nervous system derangement. At the hypotalamic level estrogen withdrawal gives rise to vasomotor symptoms, eating behavior disorders and altered blood pressure control. Psychological disturbances such as depression, anxiety, irritability and mood fluctuation are related to estrogen-induced changes in the lymbic system. The hypothesis of specific neuroanatomical and neurophysiological effects of estrogen on the brain may also explain the correlation between estrogen deficiency and cognitive disturbances such as Alzheimer's type dementia (AD). The increasing interest in the influence of sex steroids on brain function has focused attention on hormonal replacement therapy. Clinical and epidemiological studies have demonstrated that estrogen therapy exerts a positive effect on vasomotor instability and improves psychological disturbances. The positive effects of estrogen on mood are probably related to its stimulatory action on adrenergic and serotoninergic tone. Estrogen may influence the cognitive function through different biological actions. Estrogen administration increases total cerebral and cerebellar blood flow, cerebral glucose administration and improves cholinergic tone, a key neurotransmitter in learning and memory. The evidence suggests that hormone replacement therapy may reduce the relative risk of developing AD. Progestagens and androgen may also have a role in the control of mood disorders. At present, few data are available regarding the influence that selective estrogen receptor modulators, a new class of compounds, can exert on the brain.

Alzheimer Disease↗
PubMed1999

Idiopathic central retinal vein occlusion in a thrombophilic patient with the heterozygous 20210 G/A prothrombin genotype.

PURPOSE: To report the occurrence of monolateral central retinal vein occlusion in a patient with heterozygous 20210 G/A prothrombin genotype, known to be associated with high thrombophilic risk. METHODS: A monolateral central retinal vein occlusion was diagnosed in a 71-year-old woman, who had suffered from a deep vein thrombosis in her left leg at the age of 36 years. Mutations of the genes involved in the coagulation process were investigated by DNA polymerase chain reaction. RESULT: DNA analysis showed the patient to be heterozygous for the prothrombin 20210 G/A genetic variation. CONCLUSION: The 20210 G/A prothrombin gene mutation may be associated with central retinal vein occlusion.

Aged↗
PubMed1999

Quantum mechanical analysis of oxygenated and deoxygenated states of hemocyanin: theoretical clues for a plausible allosteric model of oxygen binding.

In this work with ab initio computations, we describe relevant interactions between protein active sites and ligands, using as a test case arthropod hemocyanins. A computational analysis of models corresponding to the oxygenated and deoxygenated forms of the hemocyanin active site is performed using the Density Functional Theory approach. We characterize the electron density distribution of the binding site with and without bound oxygen in relation to the geometry, which stems out of the crystals of three hemocyanin proteins, namely the oxygenated form from the horseshoe crab Limulus polyphemus, and the deoxygenated forms, respectively, from the same source and from another arthropod, the spiny lobster Panulirus interruplus. Comparison of the three available crystals indicate structural differences at the oxygen binding site, which cannot be explained only by the presence and absence of the oxygen ligand, since the geometry of the ligand site of the deoxygenated Panulirus hemocyanin is rather similar to that of the oxygenated Limulus protein. This finding was interpreted in the frame of a mechanism of allosteric regulation for oxygen binding. However, the cooperative mechanism, which is experimentally well documented, is only partially supported by crystallographic data, since no oxygenated crystal of Panulirus hemocyanin is presently available. We address the following question: is the local ligand geometry responsible for the difference of the dicopper distance observed in the two deoxygenated forms of hemocyanin or is it necessary to advocate the allosteric regulation of the active site conformations in order to reconcile the different crystal forms? We find that the difference of the dicopper distance between the two deoxygenated hemocyanins is not due to the small differences of ligand geometry found in the crystals and conclude that it must be therefore stabilized by the whole protein tertiary structure.

Allosteric Regulation↗
PubMed1999

Phenotype and genotype expression in pseudohomozygous factor VLEIDEN : the need for phenotype analysis.

The presence of a DNA mutation is frequently used to define a disease or a risk state. Because DNA typing has become easy and convenient in contrast to protein characterization, it is generally assumed that a mutation if present (or not) at the DNA level will be also present (or not) in the corresponding protein. However, discrepancies between phenotype and genotype can occur. A point mutation in the coagulation factor V gene (G1691-->A, resulting in an Arg506-->Gln amino acid substitution in the factor V molecule [factor VLEIDEN], leading to activated protein C resistance) is the most common genetic risk factor for familial thrombophilia. A pseudohomozygous factor VLEIDEN phenotype would occur if a heterozygous individual for factor VLEIDEN also did not express the "normal" (non-Leiden) factor V allele. However, to date, no data have been available to confirm the presence of only the factor VLEIDEN form in the plasma of these individuals. Platelet mRNA from 2 presumed pseudohomozygous patients and their family members was isolated, the amplified partial cDNAs were sequenced or restricted, and the allelic bands were quantified. Both patients were found to be heterozygous for the G1691-->A substitution at both the DNA and mRNA levels. The presence of either the normal or mutated form of factor V in the patients' plasmas was investigated using a monoclonal antibody to factor V that recognizes an epitope located between residues 307 and 506 of the factor Va heavy chain. No normal factor V could be detected in the plasmas of the 2 propositi. The present data demonstrate absence of a correlation between genotype at position 1691 (at the DNA and mRNA levels) and the corresponding phenotype data found in the plasmas of patients with pseudohomozygous factor VLEIDEN. Overall, these data suggest the existence of heterogeneous genetic "lesions," which interfere with factor V expression, processing, secretion, and/or stability. Because the presence of the factor VLEIDEN molecule in plasma is directly related to pathology, identification and quantification of the circulating forms of factor V in plasma may be required for the diagnosis of individuals with activated protein C resistance.

Adult↗
PubMed1999

Oral contraceptives highlight the genotype-specific association between serum phospholipids and activated factor VII.

The present analysis was undertaken to study the effect of oral contraceptive (OC) use on activated factor VII (FVIIa) in subjects characterized by FVII genotypes, with the further aim of evaluating the role of lipids in this pharmacological interaction. In OC users (n=42) and nonusers (n=130) of comparable age, we examined the FVII phenotypic variables (FVII coagulant activity [FVIIc], FVII antigen, and FVIIa), FVII genotypes (the 353R/Q and 5'F7 polymorphisms analyzed in combination; alleles M1/M2 and A1/A2, respectively), and a number of lipid and lipoprotein parameters: serum concentrations of total cholesterol (chol), low density lipoprotein and high density lipoprotein-chol, triglycerides, phospholipids (PhLs), apolipoprotein A1, and lipoprotein(a). PhLs, triglycerides, apolipoprotein A1, chol, FVII antigen, FVIIc, and high density lipoprotein-chol levels were shown to be statistically higher in users than nonusers. FVII levels, particularly those of FVIIa and FVIIc, were much higher in homozygotes for the A1 and M1 alleles (A11 M11), especially in OC users. A strong association was found between PhL and FVIIa: in the multiple regression analysis, women taking OCs who had elevated PhL concentrations also had very high levels of FVIIa, but only if their genotype was A11 M11. These results indicate that the increased FVII levels in OC users depend on the FVII genotype and that high PhL concentrations predict very high levels of FVIIa and FVIIc.

Cardiovascular Diseases↗