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Biomedical subjects

M Bergamaschi

Publications and source records attributed to M Bergamaschi.

At least 19 recordsLinked to original sources
PubMed2003

Scanning electron microscopy evaluation of the link between a new dentinal desensitizer and dentine.

AIM: The purpose of this study was to evaluate the interaction of a novel dentinal desensitizer Twin Pro with enamel-dentinal adhesive preparations or filling materials and dentine using scanning electron microscopy (SEM) technology. METHODS: Black's I class cavities were drilled extracted molar teeth free of caries or fissures, and the cavities disinfected. The specimens were divided into 4 groups of 2 teeth each treated as follows: Group A: Twin Pro, fluid (Tetric-Flow Vivadent) and micro-hybrid (Tetric-Ceram Vivadent) composites placed on the etched (Liner Bond 2V Clearfil) cavities. Group B: Twin Pro, PQ1-Ultradent loaded Primer-Bonding plus fluid and micro-hybrid composites applied to the acid-etched (37% orthophosphoric acid) cavities. Group C: Twin Pro plus Silver amalgam alloy (Phasealloy- Sybram Kerr). Group D (control group): self-etching primer plus fluid and micro-hybrid composite. Specimens were investigated by SEM. RESULTS: The results obtained in all groups show that the application of Twin Pro does not alter the adhesiveness of the restorative composite materials to the dental wall. In fact the desensitizer and the adhesive layers are indistinguishable at SEM observation, and well adherent to the dentinal surface of the cavities. CONCLUSION: The results of SEM investigations show that Twin Pro does not decrease the adhesion of restorative materials to the tooth surface, as it establishes an efficient interconnection with the different materials used, and it forms a uniform layer covering and occluding dentine tubules, and this might constitute an efficacious sealing of dentinal tubules which possibly contribute to decrease dentinal sensitivity to environmental nociceptive stimuli.

Acrylic Resins↗
PubMed2001

Preclinical evaluation of CHF3381 as a novel antiepileptic agent.

CHF3381 [n-(2-indanyl)-glycinamide hydrochloride] has been selected on the basis of a screening program as the compound displaying the highest anticonvulsant activity in the maximal electroshock seizure (MES) test and the best therapeutic index with reference to the rotarod test in mice and rats. In this study, the antiepileptic activity and the behavioural toxicity of CHF3381 were characterised in multiple model systems. CHF3381 effectively prevented MES-induced convulsions when administered i.p. (ED50, 24 mg/kg and 7.5 mg/kg) or p.o. (ED50, 21 mg/kg and 21 mg/kg) in both mice and rats, respectively. The time course of oral anti-MES activity in the rat was related to the brain concentration profile of unchanged CHF3381. Interestingly, the brain drug levels were about 4-5 times higher than in plasma. CHF3381 was very effective in mice against picrotoxin-, and i.c.v. N-methyl-D-aspartate (NMDA)-induced hind limb tonic extension (ED50 Approximately/=10 mg/kg), but was a weaker antagonist of 4-amynopyridine- and bicuculline-induced tonic seizures (ED50 approximately/=100 mg/kg), and ineffective against pentylentetrazole- and picrotoxin-induced clonic seizures. CHF3381 antagonised the behavioural effects and lethality of i.p. administered NMDA (ED50 = 57 mg/kg p.o.), indicating that the compound may act as a functional NMDA antagonist. In keeping with this idea, CHF3381 weakly displaced [(3)H]-TCP from binding to NMDA receptor channels (Ki, 8.8 microM). In the rat amygdala kindling model, CHF3381 was more efficient against kindling development than against kindled seizures (minimally active dose = 80 vs. 120 mg/kg i.p). Furthermore, it significantly increased the seizure threshold in kindled rats at relatively low doses (40 mg/kg i.p.). In contrast with MK-801-induced hyperactivity, CHF3381 moderately reduced the spontaneous locomotor activity in mice at anticonvulsant doses. Toxic effects on motor performance (rotarod test) were found at high doses only (TD50 approximately/= 300 mg/kg p.o., congruent with 100 mg/kg i.p. in both mice and rats). Furthermore, CHF3381 did not impair passive avoidance and Morris water maze responding in the therapeutic range of doses. Finally, the development of tolerance after repeated doses was negligible. These data indicate that CHF3381 exerts anticonvulsant and antiepileptogenic effects in various seizure models and possesses good therapeutic window, with scarce propensity to cause neurological side-effects.

Animals↗
PubMed1996

The involvement of the release of nitric oxide in the pharmacological activity of the new furoxan derivative CHF 2363.

1. The mechanism of action and the pharmacological effects of the new furoxan derivative, CHF 2363 (4-ethoxy-3-phenylsulphonylfuroxan), were investigated. 2. Pre-incubation of CHF 2363 with human platelet-rich plasma produced a concentration-dependent inhibition of the platelet aggregation induced by collagen, adenosine diphosphate (ADP) and platelet activating factor (PAF). The test compound was about 5 times more potent than sodium nitroprusside. 3-Isobutyl-1-methyl-xanthine (IBMX) potentiated the antiaggregating effect of CHF 2363. 3. CHF 2363 was a potent inhibitor of rubbed endothelium rabbit aortic ring contraction induced by noradrenaline. Comparison of IC50 values showed that CHF 2363 was as potent as glyceryl trinitrate (GTN). 4. Increasing concentrations of CHF 2363 elevated platelet guanosine 3':5'-cyclic monophosphate (cyclic GMP) levels. Adenosine 3':5'-cyclic monophosphate (cyclic AMP) levels were unaffected. 5. Oxyhaemoglobin reduced all the pharmacological actions of the test compound. Moreover, CHF 2363 concentration-dependently released nitric oxide (NO) in platelet-rich plasma. The NO release was correlated to its ability to increase platelet cyclic GMP levels. 6. After exposure of rat aortic strips to supramaximal concentrations of GTN (550 microM), the vasorelaxant activity of CHF 2363 did not change, although that of GTN decreased about 55 fold. 7. It has been concluded that the new furoxan derivative CHF 2363 exerts a potent antiaggregating and vasorelaxant activity via NO release and increase of cyclic GMP levels. No in vitro cross tolerance between GTN and CHF 2363 was observed.

1-Methyl-3-isobutylxanthine↗
PubMed1996

[Rehabilitation of deafness in the elderly: multidisciplinary intervention in experimental university center].

The loss of hearing abilities can be seen as a complex event because psychological discomfort and relational inhibitions interact and lead to behaviours and attitudes which are insidious and dangerous for the quality of life of the patient. The complexity of the psychological-organic inconvenience, such as impairement disability and handicap led to the testing of recovery patterns. In this specific context interventions coming from different fields sustained from a complex operative model where different professional competences and evaluation processes interact. Therapeutic interventions have been carried out by an audiologist, an audiometrist, a speech therapist, an audioprostethist and a psychologist, all sharing the obtaining of the same result. The role of the audiologist is simply clinical and concerns the knowledge of the entire process of rehabilitation through the use of a prosthesis. This process concerns the audiologist, who operates in close collaboration with the audiometrist and the audioprosthesist: it is therefore a therapeutic activity that is interested mainly in the prescription of the prosthesis and the restoring of the communicative function. The speech therapist and the psychologist carry their interventions through a relationship with the patient, which places the respect of the patient's personality before any other procedural and technical aspect. Therefore they pay attention more to ergonomic factors than to the hearing loss, through the obtaining of the patient's self-confidence and of a better general psychological situation. Therefore the main purpose of each intervention is to create a process of rehabilitation aimed at restoring the communicative functions and the individual motivation in trying to do so both in the domestic and in the social environment. The authors refer the experience and the informations put together during three years of research activity. The results of the therapeutic intervention have brought to the acceptance of the prosthesis help, the adaptation to amplification, the reduction of the subjective and relational uneasiness for the use of prosthesis, the use of the prosthesis, the reintroduction to the world of sounds, the restoring of levels of autonomy and of self-estime, the discover of eventual abilities, which had never been used or underestimated, the reactivation of more rewarding social relationships and the reduction of the conditions of dependency related to the hearing disability.

Aged↗
PubMed1995

Effect of the new nitrate ester ITF 296 on coronary and systemic hemodynamics in the conscious dog: comparison with nitroglycerin and nicorandil.

The coronary and systemic hemodynamic effects of the novel nitrate ester ITF 296 were investigated in conscious, resting dogs and compared with nitroglycerin and nicorandil. ITF 296 at 1-25 micrograms/kg i.v. elicited selective, long-lasting, and dose-dependent increases in large epicardial coronary artery diameter (CD) without affecting coronary blood flow (CBF) or coronary vascular resistance (CVR). Blood pressure (BP) and heart rate (HR) were also unaltered. At 125 micrograms/kg, ITF 296 further increased CD but simultaneously reduced CVR and mean aortic pressure and increased CBF and HR. Nitroglycerin 1-25 micrograms/kg induced a shorter and less selective dilatation of large coronary conductance arteries, as it was accompanied by a decrease in CVR at all doses used. Nicorandil produced a selective increase in left circumflex CD only at the lowest dose used (10 micrograms/kg), whereas higher doses were effective on both CD and CVR. ITF 296 significantly reduced left ventricular end-diastolic pressure and increased stroke volume (SV) and cardiac output (CO) at doses that did not alter HR or BP, indicating an increase in cardiac efficiency. In contrast, the increases in CO produced by nitroglycerin and nicorandil were dependent on the augmentation of HR, because SV was unchanged at all doses used. Nitroglycerin dose-dependently decreased BP, whereas ITF 296 reduced BP only at the highest dose used. In conclusion, ITF 296 induces a selective, flow-independent dilatation of large coronary conductance arteries without affecting the tone of small coronary resistance vessels or systemic hemodynamics over a broad range of doses. An equally selective effect was elicited by nicorandil only at the lower dose used, whereas no selective effect of nitroglycerin on the diameter of coronary conductance arteries was seen at the doses utilized in this study.

Animals↗
PubMed1995

Protective effect of the nitrate ester ITF 296 against methacholine-induced myocardial ischemia in the anesthetized rat.

The activity of ITF 296 against methacholine-induced myocardial ischemia was investigated in anesthetized rats in comparison with the organic nitrates nitroglycerin (NTG) and isosorbide dinitrate (ISDN), the K(+)-channel openers nicorandil and cromakalim, the Ca(2+)-channel blocker amlodipine, and the vasodilator dipyridamole. Given as i.v. boluses, ITF 296 (0.1-100 micrograms/kg) dose-dependently prevented methacholine-induced ST-segment elevation without affecting mean arterial blood pressure or heart rate to a significant extent. In this situation, ITF 296 was 10- to 30-fold more potent than the other coronary vasodilators tested. The protective effect of ITF 296 and ISDN against myocardial ischemia was also observed after oral administration, demonstrating good absorption and a limited first-pass metabolism of the two drugs. The anti-ischemic action of ITF 296 at 1 and 10 micrograms/kg/min was well maintained during 2 h of continuous i.v. infusion, whereas the effect of NTG and ISDN was attenuated or abolished by the end of the infusion. The new nitrate ester ITF 296 has a potent and long-lasting cardioprotective action in the anesthetized rat. The anti-ischemic effect displayed by this compound is probably mediated by an improvement of myocardial blood supply caused by pronounced coronary dilatation, whereas the contribution of systemic vasodilation is not important. Moreover, the maintenance of the anti-ischemic action during continuous i.v. infusion suggests a reduced "tolerance" development for ITF 296 compared with other nitrovasodilators.

Administration, Oral↗
PubMed1994

CHF 2206, a new potent vasodilating and antiaggregating drug as potential nitric oxide donor.

The effects of the new 3,4-disubstituted furoxan, CHF 2206, on vascular tone, platelet aggregation and platelet cyclic 3',5'-guanosine monophosphate (cGMP) levels were investigated. The compound was a potent inhibitor of rabbit aortic ring contraction induced by norepinephrine, the stable prostaglandin F2 alpha analogue, U-46619, and KCl; this activity was independent of endothelium integrity. When pre-incubated with platelet-rich plasma, CHF 2206 potently reduced in a dose-dependent manner the aggregation induced by the threshold aggregating concentration of collagen, ADP or platelet activating factor (PAF). In the same experimental conditions, the test compound increased the platelet cGMP levels and this rise was clearly associated with the inhibition of platelet aggregation. Moreover, 3-isobutyl-1-methyl-xanthine (IBMX) 5 microM potentiated the antiaggregating activity of CHF 2206. These results indicate that the increase in cGMP plays a key role in the CHF 2206-elicited responses. Oxyhemoglobin reduced all the pharmacological actions of the test compound. This evidence, along with the capacity of CHF 2206 to cause inorganic nitrite production in the presence of platelet-rich plasma, strongly suggests that nitric oxide (NO) may be a common reactive intermediate responsible for the effects induced by the drug. In conclusion, the furoxan derivative CHF 2206 exerts a potent antiaggregating and vasodilating activity with a pharmacological profile similar to the one described for NO-donating pro-drugs.

1-Methyl-3-isobutylxanthine↗
PubMed1993

Prognostic significance of nucleolar organizer regions in ovarian epithelial tumors.

Recent studies have shown that the silver-stained nucleolar organizer region (AgNOR) score is related to the cell growth rate in several neoplasms. In the work presented here, we tested the AgNOR technique in 79 ovarian epithelial tumors (13 benign, 10 borderline, 56 malignant) to evaluate the diagnostic potential of AgNOR count in distinguishing between ovarian borderline tumors and carcinomas and to assess its prognostic value in carcinomas. Ovarian carcinomas exhibited higher mean AgNOR values than borderline and benign tumors, but statistically significant differences were found only in the serous type. Statistical analysis showed a positive correlation of higher AgNOR score, advanced tumor stage, and adverse prognosis. On the contrary, low AgNOR counts identified stages I and II carcinomas with disease-free follow-up. These results suggest that the AgNOR count may improve the prognostic evaluation of ovarian epithelial tumors by representing a reliable indicator of survival.

Cell Division↗
PubMed1990

Effect of steroid hormones and antihormones on hypothalamic beta-endorphin concentrations in intact and castrated female rats.

The aim of the present study was to evaluate the effects of estrogens and androgens on hypothalamic beta-endorphin (beta-EP) concentrations. Intact or castrated female rats were chronically (2 weeks) treated with estrogen (estradiol benzoate) and/or antiestrogens (clomiphene, cyclophenil or epimestrol), and with androgens (dihydrotestosterone or dehydroepiandrosterone sulphate) and/or antiandrogen (cyproterone acetate). A group of rats treated with vehicle were studied as comparison. The beta-EP concentrations were measured by radioimmunoassay on acidic extracts of rat hypothalami. The administration of clomiphene and cyclophenil significantly reduced hypothalamic beta-EP concentrations in intact rats, while both drugs or estradiol benzoate increased the peptide concentration in castrated rats. Both intact and castrated rats treated with epimestrol showed hypothalamic beta-EP concentrations higher than vehicle treated rats. The estradiol-induced increase of beta-EP was not changed by the concomitant administration of antiestrogens. The administration of dihydrotestosterone significantly decreased beta-EP concentrations in both intact and castrated female rats, while the treatment with dehydroepiandrosterone sulphate only slightly decreased beta-EP levels in intact female rats. The cyproterone acetate-chronically treated rats showed higher beta-EP concentrations than vehicle-treated rats and these changes were reversed by the concomitant addition of dihydrotestosterone or dehydroepiandrosterone sulphate. These results showed that estrogens play a positive role while androgens negatively influence the hypothalamic beta-EP concentrations in female rats, supporting the view that central beta-EP might be a target of gonadal steroid feedback signals.

Androgen Antagonists↗
PubMed1990

Lack of cardiostimulant effects of bamifylline in in vitro and in vivo models.

The cardiac effects of bamifylline (Bamifix), an alkylxanthine derivative, were evaluated on in vivo and in vitro cardiac preparations and compared with those of theophylline and enprofylline. In isolated rat and guinea-pig right atria bamifylline, in contrast to the other xanthines, left the rate of contraction unchanged or reduced it. In isolated rat and guinea-pig left atria the compound induced only slight inotropic effects showing an intrinsic activity significantly lower than that of theophylline and enprofylline. In isolated rabbit papillary muscles bamifylline administration was without effect up to 10(-3) mol/l and decreased the contractile force at a higher concentration, while theophylline dose-dependently increased inotropism. Also in anaesthetized rabbits intravenous administration of bamifylline produced negative chronotropic and dromotropic effects that were associated, at the highest dose, with a reduction of myocardial contractility. Theophylline and enprofylline, at the same equimolar doses, induced positive chronotropic and inotropic effects. The results show that bamifylline is devoid of cardiostimulant effects in respect to other xanthine derivatives. Moreover, they suggest that bamifylline acts on cardiac muscle by a mechanism, probably linked to the Ca+(+)-movements across the cardiac membrane, able to outweigh the effects due to its antiphosphodiesterase activity.

Animals↗
PubMed1987

Effects of Org OD 14 on pituitary and peripheral beta-endorphin in castrated rats and post-menopausal women.

The aim of the first part of this study was to evaluate the effects of a new synthetic steroid (7 alpha,17 alpha)-17-hydroxy-7-methyl-19-norpregn-5(10)-en-20-yn-3-one (Org OD 14), on anterior pituitary (AP) and neurointermediate pituitary lobe (NIL) contents and on circulating levels of beta-endorphin (beta-EP) in rats. Three weeks after ovariectomy, groups of 9 rats were treated with either Org OD 14 (2 or 10 micrograms/day/rat for 14 days) or a placebo. In addition, 2 groups of ovariectomized rats were also treated with oestradiol benzoate (EB) (2 or 10 micrograms/day/rat for 14 days) to compare the effectiveness of the new steroid with that of a classical oestrogenic substance. beta-Ep concentrations were measured in plasma and in AP and NIL extracts by means of double-antibody radioimmunoassay (RIA), employing a specific anti-camel beta-EP (C-terminal fragment). Both doses of Org OD 14 induced a significant dose-related increase in plasma and pituitary lobe beta-EP concentrations as compared with the results on placebo treatment. By comparison, EB was active only at a dose of 10 micrograms/day. Despite the common stimulatory effects of EB and Org OD 14 on pituitary beta-EP, these findings suggest that the two steroids have different modes of action. The second part of the study investigated the changes in beta-EP and beta-lipotrophin (beta-LPH) plasma levels in a group of post-menopausal women treated for 6 months with Org OD 14 (2.5 mg/day) in comparison with the levels in a placebo-treated group. The clinical efficacy of Org OD 14 treatment in post-menopausal symptoms was confirmed, as well as its lack of or only transient effect on plasma lipids and lipoproteins. beta-EP and beta-LPH plasma levels were significantly higher in the Org OD 14-treated group than in the placebo group as from the second month until the end of the observation period.

Adult↗
PubMed1987

Progesterone and progestins modulate beta-endorphin concentrations in the hypothalamus and in the pituitary of castrated female rats.

Hypothalamic and pituitary beta-endorphin (B-EP) concentrations are modified by ovariectomy and estrogen treatments, supporting a direct interaction between this peptidergic system and gonadal steroids. Because the use of progestins is becoming even more diffuse in clinical practice, we evaluated the effect of progesterone and of the synthetic progestins medroxyprogesterone acetate (MPA), norethisterone acetate (NET) and desogestrel on the concentration of B-EP in the medial-basal hypothalamus and the anterior and neurointermediate pituitary lobes in ovariectomized rats (OVX), treated or untreated with estradiol benzoate (EB). B-EP concentrations were significantly increased by desogestrel in the anterior lobe and by progesterone, desogestrel and medroxyprogesterone acetate in the neurointermediate lobe. Progesterone and progestins significantly reduced B-EP increase induced by estradiol benzoate in the anterior lobe. Estradiol benzoate treatment did not modify the effect of progesterone and desogestrel on B-EP in the neuro-intermediate pituitary lobe. Norethisterone acetate and progesterone increased B-EP concentrations in the medial-basal hypothalamus, while the other steroids were inactive. In contrast, in the hypothalamus all progestins attenuated the increase of B-EP induced by estradiol benzoate (p less than 0.01). These data indicate that progesterone and progestins modulate the hypothalamic and pituitary B-EP concentrations in concert with estrogens. The capacity of progestins to modify the hypothalamic contents of B-EP may represent one of the mechanisms of action of these steroids in influencing brain function.

Animals↗
PubMed1986

Oestrous cycle-related LH responsiveness to naloxone: effect of high oestrogen levels on the activity of opioid receptors.

Endogenous opioid peptides have a tonic inhibitory control on LH secretion, participating in the functional changes of the hypothalamic-pituitary-ovarian axis. To evaluate the activity of the endogenous opioid systems during the oestrous cycle, we measured plasma LH levels after naloxone administration (5 mg/kg, s.c.) at 09.00 and 16.00 h on all days of the cycle (two further measurements were taken at 14.00 and 18.00 h on the day of pro-oestrus) and after one dose or one week's treatment with oestradiol benzoate (OB; 0.2 micrograms/rat). Concentrations of LH were measured in the same experimental models after injection of LH-releasing hormone (LHRH; 1 microgram/kg, i.p.) or saline. Naloxone induced a significant rise in LH levels on the day of oestrus, dioestrus day-1 and dioestrus day-2; this response was blunted on the morning of pro-oestrus and absent in the afternoon and after acute and chronic OB treatment. Conversely LHRH was most effective in increasing LH levels on the day of pro-oestrus and in OB-treated rats. These results indicate that opioid mechanisms, independently of the time of day and the pituitary responsiveness, exhibit a reduced activity when preovulatory changes occur, probably as a result of increased oestrogen levels.

Animals↗
PubMed1984

Inhibition of platelet aggregation by a new agent, 5-(Z,E)-13,14-didehydro-20-methyl-carbo PGI2 (FCE 22509).

FCE (+)22509, a chemically stable carboprostacyclin analogue, inhibited in vitro ADP-induced platelet aggregation in rat platelet-rich plasma (PRP) (IC50 = 7.7 ng/ml). Subcutaneous administration of the drug, inhibited both ADP-induced platelet aggregation in rat PRP (ED50 = 0.26 mg/kg) and mortality of mice induced by collagen plus adrenaline (ED50 = 0.35 mg/kg). The compound had no such preventive effects when given orally.

Adenosine Diphosphate↗
PubMed1984

Inhibitory activity of indobufen (*) on platelet aggregation in vivo.

Indobufen, administered by gavage, reduced mortality induced in mice and rabbits by intravenous injection of arachidonic acid (A.A.). The doses of compound required to protect 50% of the mice and rabbits from death (ED50) were 1.3 and 0.58 mg/kg respectively. Acetylsalicylic acid (ASA) was considerably less active than indobufen (ED50 = 22.4 and 8 mg/kg). Since the lethal effect of A.A. is mostly due to the formation of platelet aggregates (Silver et al., 1974; Kohler et al., 1976), it is concluded that indobufen is a very potent inhibitor of platelet aggregation in vivo.

Animals↗
PubMed1983

Prevention of experimentally induced gastric damage with the tripeptide ZAMI-420, a new thromboxane synthesis inhibitor.

There is accumulating evidence that the presence of the imidazole ring is essential for the inhibition of the thromboxane synthetase activity of several compounds synthetized so far. Inhibition of arachidonic acid (AA) induced platelet aggregation was observed by us with a series of tripeptides in which the imidazole ring belongs to histidine, included in a proper aminoacid sequence. Among these compounds the N-acetyl-L-phenylalanyl-L-phenylalanyl-L-histidine methylester (ZAMI-420) was the most effective. The bioassay of the supernatant of an AA-added platelet-rich plasma (PRP) preparation, preincubated with increasing concentrations of ZAMI-420, showed a dose-related reduction in thromboxane-A2 (TXA2)-like activity, an increase of PG-like response and disappearance of the TXB2 peak in the radiochromatogram; RIA experiments led to the same results. ZAMI-420 does not influence cyclooxygenase activity as the AA-induced increase in O2-consumption by the microsomal fraction of bovine seminal vesicles was unaltered by this compound. Administered orally to the rat, ZAMI-420 was able to prevent gastric damage provoked by a variety of pharmacological agents, including ASA, 5HT and alcohol. The protective effect on experimentally-induced gastric damage is not mediated through the antisecretory properties of this compound but is more likely to be due to a cytoprotective mechanism based on blockade of TXA2 synthesis.

Animals↗