Biomedical subjects

M Simoncini

Publications and source records attributed to M Simoncini.

At least 19 recordsLinked to original sources

PubMed2003

Effect of hypothyroidism on hormone profiles in virgin, pregnant and lactating rats, and on lactation.

Thyroid dysfunctions can produce reproductive problems. Untreated maternal hypothyroidism has serious consequences on development of offspring, resulting in stunted growth and mental retardation. The effects of propylthiouracyl-induced hypothyroidism (0.1 g l(-1) in drinking water starting 8 days before mating, or given to virgin rats for 30 or 50 days) on the serum profiles of hormones related to reproduction and mammary function (prolactin, growth hormone (GH), progesterone, corticosterone, oestradiol, insulin-like growth factor I (IGF-I), thyroid-stimulating hormone (TSH), triiodothyronine and tetraiodothyronine), and on mammary function in virgin, pregnant and lactating rats, were investigated. Propylthiouracyl treatment severely decreased circulating triiodothyronine and tetraiodothyronine concentrations, and increased serum TSH concentrations. Virgin rats showed prolonged periods of vaginal dioestrus, increased circulating progesterone concentrations and afternoon peaks of prolactin concentration, which are indicative of prolactin-induced pseudopregnancy. Propylthiouracyl-treated virgin rats had mammary development comparable to that of midpregnancy, and half of these rats had increased mammary casein and lactose concentrations. Serum prolactin concentrations were decreased on the afternoon of day 5 of pregnancy, increased during late pregnancy (days 15-21) and were normal during lactation. Circulating GH concentrations decreased on days 15-21 of pregnancy, whereas progesterone concentrations increased during late pregnancy and early lactation. Circulating oestradiol (measured in late pregnancy and in virgin rats), IGF-I and corticosterone concentrations were decreased. Although assessment of mammary histology showed no differences in extent of development, casein content was increased in propylthiouracyl-treated rats on day 21 of pregnancy; litter growth was severely reduced and at day 20 of age the pups were hypothyroid, with decreased GH serum concentrations. An acute suckling experiment was performed on days 10-12 of lactation to determine whether some impairment in mammary function or the suckling reflex might account for these differences. After an 8 h separation of mothers from their litters and 30 min of suckling, circulating prolactin values were not affected by propylthiouracyl treatment, but serum oxytocin concentration and milk excretion were reduced. In conclusion, hypothyroidism induces various alterations in the hormone profiles of virgin and pregnant rats, and induces pseudopregnancies and mammary development in virgin rats. These alterations do not appear to have an overt impact on the outcome of pregnancy and on mammary function during lactation, with the exception of the milk ejection reflex, which may account at least partially for the reduced litter growth.

Animals↗

PubMed2002

Evidence of oxidative imbalance in long-term liver transplant patients.

BACKGROUND: Oxidative stress in patients undergoing liver transplantation results both from the pre-existing cirrhosis and ischaemia-reperfusion injury related to surgery. Previous studies have provided information limited to the immediate post-operative period. It remains to be established whether this oxidative imbalance is reversed in a longer time. AIM, METHODS AND PATIENTS: This study aimed to compare plasma concentrations of thiobarbituric acid-reactant substances and alpha-tocopherol in 20 cirrhotic patients before liver transplantation and 22 patients in whom transplant had been carried out at least 6 months previously. Thirty healthy age and sex-matched volunteers served as controls (cross-sectional study). Five patients were evaluated before and after liver transplantation (longitudinal study). RESULTS AND CONCLUSIONS: Pre-transplant patients showed greater thiobarbituric acid-reactant substances and lower alpha-tocopherol levels than controls. Transplanted patients presented lower thiobarbituric acid-reactant substances and greater alpha-tocopherol levels than cirrhotic patients without reaching, however, the levels observed in controls. No correlations were found between oxidative parameters and liver tests. Hypertransaminasaemia, liver disease recurrence, and rejection episodes did not significantly influence the oxidative parameters. In the longitudinal study, transplantation induced a significant decrease in plasma thiobarbituric acid-reactant substances and a rise in alpha-tocopherol. Although a long-term improvement in the oxidative injury observed in cirrhotic patients occurs after liver transplantation, mild oxidative stress persists even in successfully transplanted patients.

Adult↗

PubMed2001

Gender affects reperfusion injury in rat liver.

Sex mismatch is a well-known risk factor for chronic rejection of liver allografts, but the mechanisms involved remain unclear. Since experimental observations suggest that female liver is more sensitive to reperfusion injury than male liver, we assessed the influence of gender on oxidative stress. Livers from male and female rats were exposed to warm ischemia and reperfused by an oxygenated buffer. Chemiluminescence was continuously recorded. Reduced and oxidized glutathione and malondialdehyde lactic dehydrogenase values were also determined. Chemiluminescence increased during reperfusion in both groups, but was significantly greater in livers from female rats. Malondyaldehyde and lactic dehydrogenase progressively increased in all animals, reaching significantly greater values in female rats. Livers from female rats showed an increase in all the parameters of oxidative stress compared to male animals. A greater susceptibility to reperfusion injury may be evoked as an alternative mechanism to explain the poor outcome of female organ after liver transplantation.

Animals↗

PubMed2001

Oxygen free radical production in rat liver: dose-related effect of ethanol on reperfusion injury.

Ethanol is known to have a deleterious effect on liver ischemia-reperfusion injury, but recent reports suggest that light ethanol consumption may produce a protective effect in several organs. We aimed to investigate effects of different doses of ethanol on liver oxidative injury. Rats were fed with ethanol-containing diets (24, 30, 36, 40% for groups A, B, C, D, respectively). After four weeks, livers were exposed to ischemia-reperfusion. Chemiluminescence was recorded; total lipids, adenosine triphosphate, malondialdehyde, reduced glutathione and lactic dehydrogenase were assessed. In all groups, ischemia resulted in the disappearance of O2*-, a decrease in glutathione and adenosine triphosphate, and stable malondialdehyde values. During the reperfusion phase, O2*- production, malondialdehyde and lactic dehydrogenase increased, reaching significantly higher values in groups C and D and significantly lower values in group B. The effect of ethanol on ischemia-reperfusion injury seems to be a dose-related response, with an additional toxic effect only at high doses of ethanol.

Adenosine Triphosphate↗

PubMed1999

Ischemia-reperfusion injury in rat fatty liver: role of nutritional status.

Fatty livers are more sensitive to the deleterious effects of ischemia-reperfusion than normal livers. Nutritional status greatly modulates this injury in normal livers, but its role in the specific setting of fatty liver is unknown. This study aimed to determine the effect of nutritional status on warm ischemia-reperfusion injury in rat fatty livers. Fed and fasted rats with normal or fatty liver induced by a choline deficient diet underwent 1 hour of lobar ischemia and reperfusion. Rat survival was determined for 7 days. Serum transaminases, liver histology and cell ultrastructure were assessed before and after ischemia, and at 30 minutes, 2 hours, 8 hours, and 24 hours after reperfusion. Survival was also determined in fatty fasted rats supplemented with glucose before surgery. The preischemic hepatic glycogen was measured in all groups. Whereas survival was similar in fasted and fed rats with normal liver (90% vs. 100%), fasting dramatically reduced survival in rats with fatty liver (14% vs. 64%, P <.01). Accordingly, fasting and fatty degeneration had a synergistic effect in exacerbating liver injury. Mitochondrial damage was a predominant feature of ultrastructural hepatocyte injury in fasted fatty livers. Glucose supplementation partially prevented the fasting-induced depletion of glycogen and improved the 7-day rat survival to 45%. These data indicate that rat fatty livers exposed to normothermic ischemia-reperfusion injury are much more sensitive to fasting than histologically normal livers. Because glucose supplementation improves both the hepatic glycogen stores and the rat survival, a nutritional repletion procedure may be part of a treatment strategy aimed to prevent ischemia-reperfusion injury in fatty livers.

Alanine Transaminase↗

PubMed1999

Porcine living liver transplantation using a vascular prosthesis to replace the intrahepatic vena cava.

BACKGROUND: This study aimed to determine whether the porcine model could be adapted to accommodate living donor liver transplantation (LLT). Because the pig hepatic anatomy precludes a standard approach, a study was designed to evaluate the results using a segment of vascular prosthesis to replace the intrahepatic portion of the inferior vena cava (IVC) with establishment of hepatic venous drainage into the graft. METHODS: A total of 10 LLT were performed using 20 pigs. After left hepatectomy, the intrahepatic IVC was replaced with a modified aorto-iliac prosthesis, anastomosing the proximal (aortic limb) to the infradiaphragmatic IVC, one distal iliac limb to infrahepatic IVC and the other (after shortening) to establish hepatic venous drainage after transplant. Conventional venous bypass was used, and no immunosuppressives were administered. RESULTS: All donors survived the 10-day posthepatectomy observation period. Eight of the 10 transplanted pigs survived at least 2 days (mean 7.6 days; range 3-13 days). No evidence of caval graft thrombosis was observed. CONCLUSIONS: Replacement of the recipient intrahepatic IVC by a vascular prosthesis allows to overcome the major technical obstacle which has limited the use of pigs in LLT.

Anastomosis, Surgical↗

PubMed1998

Chemiluminescent real time imaging of post-ischemic oxygen free radicals formation in livers isolated from young and old rats.

Oxygen free radicals generation is a major cause of liver injury during reperfusion. Luminescence analysis has been recently proposed to measure free radical generation by isolated cells or organs, but it allows only global tissue luminescence. Using a special Saticon videocamera with image intensifier we aimed to visualize and localize oxygen free radical generation in isolated perfused livers exposed to an oxydative stress. Livers isolated from rats aged 4 and 30 months were exposed to ischemia/reperfusion; photons emission by the organs was continuously recorded. Lucigenin was utilized as a chemiluminigenic probe to assess superoxide anion generation. In both groups, chemiluminescence was not detectable during ischemia, while it was observed after reperfusion. Photons emission started after few minutes of reperfusion, was maximal after 15-20 min and disappeared within 50-60 min. Chemiluminescence emitted by livers from younger rats however, was significantly higher when compared to chemiluminescence emitted by organs isolated from old rats (0.8 +/- 0.1 vs 0.44 +/- 0.08 photons x 10(5)/s, respectively, after 15 min; p < .01). The superimposition of chemiluminescent and live image permitted to determine the regional production rate and distribution of photons. In conclusion, the age of the rats influences significantly the amount of oxyradicals produced in the liver during post-ischemic reperfusion. The method described, allowing the visualization in real time of oxygen free radicals generation on the surface of isolated intact organs, represents a novel and potent tool for the study of oxidative stress.

Acridines↗

PubMed1998

Delineating a putative phobic-anxious temperament in 126 panic-agoraphobic patients: toward a rapprochement of European and US views.

BACKGROUND: The current US official position, since DSM-III, is that panic attacks represent the hallmark of panic disorder and play a major role in the development of the agoraphobic syndrome. The more favoured view in the European tradition is that neurotic personality and/or prodromal features such as mild depression and excessive worries precede the illness. METHOD: We studied 126 consecutive cases of panic disorder with or without agoraphobia by DSM-III-R criteria, evaluated by relevant structured and semi-structured interviews. RESULTS: We provide evidence that characterological and prodromal antecedents represent a putative phobic-anxious temperamental substrate occurring in at least 30% of our sample. This temperament consists of three or more of the following traits: (1) increased sympathetic activity with repeated sporadic and isolated autonomic manifestations; (2) marked fear of illness; (3) hypersensitivity to separation; (4) difficulty to leave familiar surroundings; (5) marked need for reassurance; (6) oversensitivity to drugs and substances. Our data further suggest that these attributes are of familial origin, as a result of which the illness tends to declare itself earlier. LIMITATION: The present investigation is largely correlational without a prospective component; however, the key validating familial data were obtained blindly. CONCLUSION: Our data support a pathogenetic model whereby genetic diathesis unfolds from subclinical to clinical manifestations along temperamental, panic, phobic and avoidant patterns. We submit that the delineation of the phobic-anxious temperament will be useful in more completely charting the life course of the panic-agoraphobic spectrum; avoidant and dependent (Axis II) patterns appear more distal in the pathogenetic chain and, in many cases, can be conceptualized to be epiphenomenal to the disease process.

Adolescent↗

PubMed1998

Beer affects oxidative stress due to ethanol in rats.

The relationship between chronic moderate beer consumption and oxidative stress was studied in rats. Animals were fed three different isocaloric diets for six weeks: a beer-containing diet (30% w/w), an ethanol-supplemented diet (1.1 g/100 g, the same as in the beer diet) and an alcohol-free basal diet. At the end of the feeding period, rats were analyzed for plasma and liver oxidative status. Some livers were isolated and exposed to ischemia-reperfusion to assess the additional oxidative stress determined by reperfusion. No significant differences in plasma antioxidant status were found among the three dietary groups. Lipoproteins from the beer group, however, showed a greater propensity to resist lipid peroxidation. Ischemia caused a decrease in liver energy and antioxidant status in all groups. Nevertheless, ATP was lower in the livers of rats exposed to the ethanol diet. During reperfusion, lipoperoxidation increased significantly in all groups. However, livers obtained from ethanol-treated rats showed the higher formation of lipoperoxides. In conclusion, a moderate consumption of beer in a well-balanced diet did not appear to cause oxidative stress in rats; moreover, probably through its minor components, beer could attenuate the oxidative action of ethanol by itself.

Adenosine Triphosphate↗

PubMed1998

Effect of ischemia--reperfusion on heat shock protein 70 and 90 gene expression in rat liver: relation to nutritional status.

Heat shock proteins are intracellular proteins associated with a generalized response of cells to stress. The purpose of this study was to assess RNA levels of heat shock protein 70 and 90 in fed or fasted rat livers during ischemia-reperfusion. Northern blot analysis of heat shock proteins was performed. Adenosine triphosphate and glutathione were assessed. In baseline conditions, livers of fasted rats showed a twofold increase in mRNA for both heat shock proteins and 38% and 43% reductions in adenosine triphosphate and glutathione, respectively, when compared with organs from fed rats. After ischemia, livers of fasted rats presented a twofold decrease in heat shock protein mRNA, while no changes were observed in livers of fed rats; reduced glutathione and adenosine triphosphate decreased 55% and 50% in fasted livers and 25% and 20% in fed organs, respectively. After 120 min of reperfusion, heat shock protein mRNA rose threefold in fasted livers, while a slight decrease was observed in the fed group; reduced glutathione and adenosine triphosphate returned to 65% and 70% of baseline values in fasted livers and 85% and 90% in fed organs, respectively. In conclusion, the nutritional status affects heat shock protein expression determined by reperfusion. The reduced antioxidant status leading to increased oxidative stress could be the mechanism underlying the phenomenon.

Adenosine Triphosphate↗

PubMed1998

Ageing affects anoxia/reoxygenation injury in rat hepatocytes.

BACKGROUND: The reoxygenation phase after a period of anoxia leads to oxyradical formation, responsible for damage to cell membranes. Ageing is associated with functional and structural changes in liver cells, which modify their sensitivity to reoxygenation injury. The aim of this study was to determine the effects of ageing on the sensitivity of hepatocytes to anoxia/reoxygenation. METHODS: Oxyradical formation and cell injury were evaluated in hepatocytes isolated from rats of different ages exposed to 2 h of anoxia and 1 h of reoxygenation. Anion superoxide was measured by lucigenin-enhanced chemiluminescence, hydrogen peroxide by luminol-enhanced chemiluminescence, and cell damage by lactate dehydrogenase (LDH) release. RESULTS: During anoxia, oxyradical production dropped to background levels in both groups. LDH release was significantly greater in ageing hepatocytes. During reoxygenation, a massive generation of anion superoxide and hydrogen peroxide, followed by a sharp increase in LDH release, was observed in both groups. However, both oxyradicals and cell injury were significantly greater in liver cells obtained from ageing rats. CONCLUSIONS: The data confirm that hepatocytes produce high levels of free radicals during post-ischemic reoxygenation and suggest that ageing cells are more sensitive to reperfusion injury.

Aging↗

PubMed1998

Corticosteroid receptors in mononuclear leucocytes of obese subjects.

Abnormalities of the hypothalamus-pituitary-adrenal axis and hypersensitivity to corticosteroids have been suggested as major determinants of the development of visceral obesity. Since at the cellular level most effects of corticosteroids are mediated by specific receptors, we evaluated the number of type I and type II corticosteroid receptors in mononuclear leucocytes of 26 obese and 13 control subjects. We also studied the relationship between corticosteroid receptors, measured by radioreceptor assay, and abdominal visceral fat, evaluated by computed tomography scan, plasma and urine corticosteroid hormone concentrations and overall glucose metabolism, assessed by euglycaemic-hyperinsulinaemic clamp. We observed a decrease in type II receptors in the obese subjects (1746 +/- 160 vs 2829 +/- 201 per cell; P < 0.0001), with no change in type I receptors. Type II receptors decreased in relation to body mass index (r = -0.53; P < 0.005) and total glucose disposal (r = 0.51; P < 0.01). Abdominal visceral fat did not correlate with type II receptor number, but did correlate with total glucose disposal (r = -0.35; P < 0.05); the rate of glucose disposal was lower in obese subjects (3.3 +/- 0.3 vs 7.4 +/- 0.4 mg/kg per min; P < 0.001). Plasma and urine cortisol did not differ between the two groups. However, a direct correlation between type II receptor number and both plasma (r = 0.43; P < 0.02) and urine cortisol concentrations (r = 0.60; P < 0.05) was observed. In conclusion, the number of type II corticosteroid receptors in mononuclear leucocytes was found to be lower in obese subjects. This abnormality appears to be related to the degree of adiposity and to the main endocrine-metabolic features of the obesity syndrome, further supporting the hypothesis of involvement of hypothalamus-pituitary-adrenal axis hyperactivity in the pathophysiology of obesity.

Adult↗

PubMed1998

Regulation of corticosteroid receptors in patients with anorexia nervosa and Cushing's syndrome.

We have studied 16 patients with anorexia nervosa (11 with a stabilised weight loss and 5 in the weight-losing phase), 11 healthy controls, and 10 patients with Cushing's syndrome, by measuring plasma cortisol (by enzyme-immunoassay), ACTH (by RIA), corticosteroid (Type I-mineralocorticoid and Type II-glucocorticoid) receptors in mononuclear leukocytes (by radio-receptor assay), and lymphocyte subpopulations (by cytofluorimetry). In anorexic patients with a stabilised weight loss and in Cushing's syndrome the mean value of both Type I and Type II corticosteroid receptors in mononuclear leukocytes was significantly lower than in controls. The correlation between Type II receptors and plasma cortisol was inverse in stabilised anorexia nervosa and in Cushing's syndrome, and direct in healthy controls. Anorexic patients in the weight-losing phase showed a significant increase in plasma cortisol levels and a normal number of Type II receptors. From these results we hypothesise that in anorexia nervosa there is a progression from an increase in plasma cortisol in the weight-losing phase, to a concomitant decrease in Type II receptors when the disease is stabilised.

Adolescent↗

PubMed1996

Dexamethasone suppression test: corticosteroid receptors regulation in mononuclear leukocytes of young and aged subjects.

The dexamethasone suppression test (DST) is considered an indicator of the function of the adrenal pituitary axis. The effect of the steroid is mediated by its binding to corticosteroid receptors. We previously suggested that the measurement of corticosteroid receptors in lymphocytes is an index of an analogous pattern in brain. In the present study, corticosteroid Type I and Type II receptors in mononuclear leukocytes were measured in 10 elderly subjects and in 9 young adults, before and after overnight DST (1 mg). Receptors were measured by radioreceptor assay. In all the subjects, dexamethasone was able to suppress plasma cortisol. The number of Type I and Type II receptors before the test was lower in elderly subjects than in adults. In the control group, dexamethasone produced a significant depression of Type I receptors (from 267 +/- 72 to 169 +/- 71 receptors per cell), which can be interpreted as a primary involvement of Type I receptors in the response to dexamethasone; Type II receptors decreased in half the subjects (from 2849 +/- 703 to 2345 +/- 569 receptors per cell). In elderly healthy subjects, Type II receptors were also significantly decreased (from 1796 +/- 671 to 720 +/- 345). We suggest that in young subjects Type II receptors are initially up-regulated by dexamethasone, and then down-regulated, while in aged subjects an up-regulation cannot be achieved, as suggested by the higher values of plasma cortisol usually found in aging subjects.

Adult↗

PubMed1996

Further studies on the mechanism of the mineralocorticoid action of licorice in humans.

The pathogenesis of pseudohyperaldosteronism from licorice has been evaluated in 6 male volunteers taking daily 7 g of a commercial preparation of licorice for 7 days, corresponding to an intake of 500 mg/day of glycyrrhizic acid. Pseudohyperaldosteronism was evident during the treatment (increase of body weight, suppression of plasma renin activity and plasma aldosterone, reduction of serum potassium). The ratio (tetrahydrocortisol + allo tetrahydrocortisol)/tetrahydrocortisone in urine increased in 5 cases after 3 days of treatment, without an increase of plasma mineralocorticoid activity (PMA). In the 6th case the urinary ratio was unchanged and PMA increased from the pretreatment value. After 7 days of therapy the ratio remained high and PMA was not measurable in 3 cases, while in the other 3 cases the ratio returned to pretreatment and PMA was higher than pretreatment value. We conclude that the pseudohyperaldosteronism from licorice is initially related to decreased activity of 11 beta-hydroxysteroid-dehydrogenase and afterwards also a direct effect of licorice derivatives on mineralocorticoid receptors becomes evident in some cases. In other cases however the effect on the enzyme is prevailing probably due to individual factors.

11-beta-Hydroxysteroid Dehydrogenases↗

PubMed1996

Benzodiazepine binding inhibitory activity: new supportive findings on its presence in psychiatric patients and further biochemical analyses.

The authors investigated the presence of a serum activity inhibiting the specific binding of 3H-flunitrazepam (which labels the central benzodiazepine receptors) (BBIA) in patients with different psychiatric disorders and analyzed it by means of high performance liquid chromatography (HPLC) analysis. The results showed that the lowest activity was present in healthy controls who were not different from patients with schizophrenia and obsessive-compulsive disorder. On the contrary, the BBIA values of these 3 groups of patients were significantly lower than those found in patients with bipolar disorder in various phases (depressive, mixed or manic), in unipolar depressives and in patients with panic and delusional disorders. The HPLC analysis of the serum extracts revealed the presence of 3 peaks of activity which were differently distributed in the patients and in the healthy controls, peak 3 being totally absent in the last group and mainly represented in bipolar depressives. The GABA ratio values showed that peaks 1 and 2 behave as agonists while peak 3 behaves as an inverse agonist. The mass fragmentography of the different peaks is in progress.

Adult↗

PubMed1992

Occupational thyroid disease.

A case of thyrotoxicosis due to the occupational exposure to cosmetics in a 35-year-old beautician is reported. The hormonal pattern was consistent with exogenous thyroid hormone administration, but not with iodine hyperthyroidism. The patient denied she was using thyroid hormones; also, she lacked the typical features of patients with thyrotoxicosis factitia. Her occupational history was carefully reviewed: A heavy exposure of the unprotected skin to cosmetic creams containing iodine, thyroid hormones, and thyroid extracts had occurred in the previous months. The patient was advised to refrain from the exposure, and a persistent remission of thyrotoxicosis was observed thereafter. This case suggests that percutaneous absorption of thyromimetic substances though never described before, may occur in an occupational setting. We advise that such cosmetics be handled with care, not only by patients with thyroid disease but by euthyroid subjects as well; close medical surveillance over the use of such preparations seems appropriate.

Adult↗

PubMedDate not supplied

Prenatal exposure to ethanol in rats: effects on liver energy level and antioxidant status in mothers, fetuses, and newborns.

The fetal alcohol syndrome is a clinical condition that affects newborns from alcoholic mothers. It is not clear, however, whether ethanol consumption during gestation can affect liver functions of fetuses and newborns. In this study, we aimed to assess the effects of ethanol administration on body weight, liver energy level, and antioxidant status of mothers, fetuses, and newborns. Pregnant rats were exposed to ethanol during the third week of gestation. Body weight, survival, and liver concentration of gluthatione (GSH) and adenosintriphosphate (ATP) were measured. No differences were observed in body weight or in liver ATP and GSH between mothers exposed to ethanol and control animals. Conversely, fetuses from rats exposed to ethanol showed a marked decrease in GSH, ATP, and body weight when compared to those from control rats. Newborns exposed prenatally to ethanol were no different from those born to control mothers. This study suggests that an amount of ethanol that is not sufficient to determine a significant effect on mothers can, nevertheless, cause a marked decrease in growth and in liver antioxidant and energy status in fetuses. These parameters, however, return to control value one week after ethanol discontinuation.

Adenosine Triphosphate↗