Response of periodontium to mineral trioxide aggregate and Biodentine: a pilot histological study on humans.

BACKGROUND: The aim of this study was to investigate for the first time the histological response of human periodontium to mineral trioxide aggregate (MTA) and Biodentine. METHODS: Six patients scheduled for implant full-arch rehabilitation were randomly assigned to one of the two test groups: MTA or Biodentine treatment. For each patient, two teeth scheduled for strategic extraction were randomly assigned either to the test or to the control treatment. A lateral perforation was drilled on the root and either repaired with MTA/Biodentine or filled with gutta-percha(control). Three months later, the teeth were extracted along with the coronal third of the alveolar bone and a portion of gingival tissue, while performing implant placement, and processed for histological analysis. RESULTS: Biodentine resulted in less extrusion into the periodontal environment. All the materials showed good biocompatibility. A new mineralized cementum-like tissue incorporating periodontal fibres was visible in all cases treated with MTA. A small amount of new mineralized tissue was found in two Biodentine cases but not in control cases. Biodentine resulted in less damage to the periodontal ligament. CONCLUSIONS: Bioactivity and biocompatibility of MTA were confirmed in human models. Biodentine proved to be biocompatible, but it seems not to induce cementum regeneration.

Arrest of G(1)-S progression by the p53-inducible gene PC3 is Rb dependent and relies on the inhibition of cyclin D1 transcription.

The p53-inducible gene PC3 (TIS21, BTG2) is endowed with antiproliferative activity. Here we report that expression of PC3 in cycling cells induced accumulation of hypophosphorylated, growth-inhibitory forms of pRb and led to G(1) arrest. This latter was not observed in cells with genetic disruption of the Rb gene, indicating that the PC3-mediated G(1) arrest was Rb dependent. Furthermore, (i) the arrest of G(1)-S transition exerted by PC3 was completely rescued by coexpression of cyclin D1 but not by that of cyclin A or E; (ii) expression of PC3 caused a significant down-regulation of cyclin D1 protein levels, also in Rb-defective cells, accompanied by inhibition of CDK4 activity in vivo; and (iii) the removal from the PC3 molecule of residues 50 to 68, a conserved domain of the PC3/BTG/Tob gene family, which we term GR, led to a loss of the inhibition of proliferation as well as of the down-regulation of cyclin D1 levels. These data point to cyclin D1 down-regulation as the main factor responsible for the growth inhibition by PC3. Such an effect was associated with a decrease of cyclin D1 transcript and of cyclin D1 promoter activity, whereas no effect of PC3 was observed on cyclin D1 protein stability. Taken together, these findings indicate that PC3 impairs G(1)-S transition by inhibiting pRb function in consequence of a reduction of cyclin D1 levels and that PC3 acts, either directly or indirectly, as a transcriptional regulator of cyclin D1.

Developmental expression of PC3 gene is correlated with neuronal cell birthday.

We examined the developmental expression of PC3, a nerve growth factor (NGF) early induced gene in PC12 cells, in the rat central nervous system (CNS) and we found that it represents a molecular marker of ongoing postmitotic neurons production. PC3 is initially expressed in the ventral quarter of the neural tube, at the level of the presumptive cervical spinal cord just where and when (10-11 days post coitum (dpc)) the motor neurons are arising. Subsequently, the appearance of PC3 expression follows a ventro-dorsal and a rostro-caudal gradient in the spinal cord and a caudo-rostral gradient across the brain vesicles that coincide, both spatially and temporally, with the gradients of neurogenesis described in the literature. As in PC12 cells, PC3 mRNA expression appears to be transient in vivo. In all regions of the CNS, it is restricted to the ventricular zone of the neuroepithelium, while neuronal precursors cease to express PC3 as they migrate to the mantle zone. Moreover, PC3 mRNA disappears from the various regions of the CNS as neurogenesis ceases.

One month of streptozotocin-diabetes induces different neuroendocrine and morphological alterations in the hypothalamo-pituitary axis of male and female rats.

LHRH (median eminence) and LH (pituitary and plasma) from male and female Sprague-Dawley rats were assayed 1 month after streptozotocin injection and compared with values in controls either fed ad libitum or offered a restricted diet. Plasma LH was also assayed after stimulation with exogenous LHRH or naloxone. In diabetic males, the median eminence LHRH content and the plasma LH response to exogenous LHRH were unaltered, pituitary LH was increased, and plasma LH was decreased under basal conditions and after naloxone treatment. In diabetic females, while the median eminence LHRH content and the plasma LH response to exogenous LHRH or naloxone were reduced, pituitary and plasma LH levels were not different. Measurements made in undernourished rats excluded the possibility that the alterations found in diabetic animals were nutrition dependent. In parallel experiments, hypothalami and pituitaries were examined morphologically. In diabetic animals, degenerate axons, mainly of the LHRH type, were found in the arcuate nucleus and median eminence, and LH gonadotrophs were altered and more numerous. Strong differences between control males and females were revealed by morphometry; moreover, diabetic females had higher brain weights and fewer LH gonadotroph changes than diabetic males. These studies indicate that 1) the hypothalamo-pituitary changes that occur early in our streptozotocin-treated rats are unrelated to undernourishment and are possibly caused by insulin deficiency; 2) the LHRH axonal lesions might play a primary pathogenic role in the hypothalamo-pituitary disorder; 3) some anatomical data indicate that the brain and pituitary are less severely affected by diabetes in female than in male animals; and 4) differences between control males and females may account for some of the dissimilarities between the sexes observed under diabetic conditions.

Effects of the desensitization by morphine of the opiate-dependent adenylate cyclase system in the rat striatum on the activity of the inhibitory regulatory G protein.

Opiates act through a specific receptor to inhibit the striatal adenylate cyclase [ATP pyrophosphate-lyase (cyclizing), EC 4,6.1.1] and stimulate a high-affinity GTPase (EC 3.6.1). The present study analyzes the functions of the striatal adenylate cyclase complex following chronic morphine treatment in the rat. The inhibitory effects of GTP on basal adenylate cyclase activity, between 10(-6) and 10(-4) M, were reduced. Moreover, the half-maximal inhibitory concentration of the opiate receptor agonist (D-Ala2-Met5)-enkephalinamide (DAME) on striatal adenylate cyclase activity was increased by about four times, whereas the maximal effect was reduced in membranes from treated rats. In parallel, the half-maximal stimulatory concentration of DAME on GTPase was increased by two times, and the maximal stimulation was reduced from 60 to 25%. Binding studies performed with [3,5-3H]DAME (saturation curves) and with [3H]naloxone (competition curves) did not show any change in opiate receptor numbers and affinity. Moreover, the kinetics of the activation of the inhibitory GTP binding protein (Gi) which transduces the opiate receptor effect on adenylate cyclase showed a small but significant delay. Therefore, hypofunction of Gi can be, at least in part, responsible for the observed desensitization by morphine of the opiate-dependent GTPase and adenylate cyclase.

Expression of the PC4 gene in the developing rat nervous system.

PC4 is an early NGF-inducible gene, transiently expressed during the in vitro differentiation of PC12 cells toward a neuronal phenotype. By in situ hibridization analysis, we found that PC4 is expressed at high levels along the whole neural tube of early rat embryos. PC4 mRNA expression is not uniform across the wall of the neural tube, the autoradiographic signal being most intense on the ventricular layer. At later stages, when the rate of proliferation and production of postmitotic neurons decreases, PC4 gene expression also decreases and becomes restricted to the telencephalon, that is the last region to complete neurogenesis. Thus the expression of PC4 gene, although not exclusive of proliferating cells, appears to be correlated to the time span of proliferation of neuronal and glial precursors.

Presence of opiate receptors on striatal serotoninergic nerve terminals.

After degeneration of serotoninergic neurons induced by either transection of the ascending neuronal pathways originating from the nucleus raphe dorsalis or intraventricular 5,6-dihydroxytryptamine administration, the number of binding sites for [3H]D-Ala2, Met5-enkephalinamide was significantly reduced. This decrease in binding sites does not seem to be related to the opiate receptors present on dopaminergic terminals, nor is it due to a simple decrease in serotoninergic neuronal tone, since after p-chlorophenylalanine (100 mg/kg X 4 days) the number of striatal binding sites for the opiate ligand was not diminished. On the other hand, shortly after mechanical interruption of the raphe-striatal serotoninergic fibers, at a time when the metabolic processes are still functioning in the lesioned neurons, morphine still increased the striatal content of 5-hydroxyindoleacetic acid. These results suggest the presence of opiate receptors on striatal serotoninergic terminals, where they may modulate the presynaptic activity of these neurons.

Interactions between serotonergic and enkephalinergic neurons in rat striatum and hypothalamus.

We report evidence for an interaction between serotonergic and enkephalinergic neurons in rat striatum and hypothalamus. The administration of drugs such as p-chlorophenylalanine (PCPA), 5,6-dihydroxytryptamine (5,6-DHT) and fenfluramine that lower the striatal and hypothalamic serotonin (5-HT) content caused an increase in Met-enkephalin-like immunoreactive material (ME-IR) in these brain areas. Moreover, chronic treatment with PCPA induced an increase in the number of striatal [3H][D]Ala2,Met5]enkephalinamide binding sites. These observations suggest that serotonergic neurons modulate the functional activity of enkephalinergic neurons in the rat striatum and hypothalamus. The significance of this interaction is discussed.

Pertussis toxin inhibits the antinociceptive action of morphine in the rat.

The influence of pertussis toxin (PTX) injected intracerebroventricularly (i.c.v., 0.5 micrograms) on the analgesic effect induced in the rat by i.c.v. injection of morphine (5 micrograms) was studied. Morphine analgesia was unaffected 24 h after toxin administration, but there was a significant decrease after 6 days. Therefore a PTX-sensitive substrate, probably a guanine nucleotide regulatory protein could be involved in the coupling of opiate receptors to cellular effectors responsible for the expression of the antinociceptive action of morphine.

Opiate tolerance and dependence is associated with a decreased activity of GTPase in rat striatal membranes.

In vitro addition of opiates to rat striatal membranes significantly stimulated a low Km GTPase activity. The opioid peptide (D-Ala2, Met5) enkephalinamide was ten folds more active than morphine to elicit the effect while the kappa agonist ethylketocyclazocine was almost inactive. Opiate stimulation was antagonized by naloxone, indicating that specific opiate receptors were involved. Moreover, the effect was stereospecific since levorphanol significantly increased the GTPase activity while its enantiomer dextrorphan was completely inactive, even at concentrations as high as 100 microM. On the other hand, opiates have been reported to inhibit striatal adenylate cyclase whose activity is dependent on GTP. Our data suggest therefore that stimulation of GTPase can be the mechanism by which opiates lower adenylate cyclase activity. This view is supported by the finding that in striatal membranes of rats made tolerant-dependent to morphine, GTPase activity was significantly decreased. Narcotic tolerance and dependence is in fact associated to hyperactivity of adenylate cyclase. It is concluded that GTPase could be the primary site on which opiates act to produce the acute or chronic effects on adenylate cyclase activity.

The gene PC3(TIS21/BTG2), prototype member of the PC3/BTG/TOB family: regulator in control of cell growth, differentiation, and DNA repair?

PC3(TIS21/BTG2) is the founding member of a family of genes endowed with antiproliferative properties, namely BTG1, ANA/BTG3, PC3B, TOB, and TOB2. PC3 was originally isolated as a gene induced by nerve growth factor during neuronal differentiation of rat PC12 cells, or by TPA in NIH3T3 cells (named TIS21), and is a marker for neuronal birth in vivo. This and other findings suggested its implication in the process of neurogenesis as mediator of the growth arrest before differentiation. Remarkably, its human homolog, named BTG2, was shown to be p53-inducible, in conditions of genotoxic damage. PC3(TIS21/BTG2) impairs G(1)-S progression, either by a Rb-dependent pathway through inhibition of cyclin D1 transcription, or in a Rb-independent fashion by cyclin E downregulation. PC3(TIS21/BTG2) might also control the G(2) checkpoint. Furthermore, PC3(TIS21/BTG2) interacts with carbon catabolite repressor protein-associated factor 1 (CAF-1), a molecule that associates to the yeast transcriptional complex CCR4 and might influence cell cycle, with the transcription factor Hoxb9, and with the protein-arginine methyltransferase 1, that might control transcription through histone methylation. Current evidence suggests a physiological role of PC3(TIS21/BTG2) in the control of cell cycle arrest following DNA damage and other types of cellular stress, or before differentiation of the neuron and other cell types. The molecular function of PC3(TIS21/BTG2) is still unknown, but its ability to modulate cyclin D1 transcription, or to synergize with the transcription factor Hoxb9, suggests that it behaves as a transcriptional co-regulator.

Early gene regulation by nerve growth factor in PC12 cells: induction of an interferon-related gene.

Nerve growth factor (NGF) induces the chromaffin cell line PC12 to differentiate into cells with many of the properties of sympathetic neurons. We investigated the early differentiative phase and identified a gene, PC4, rapidly and transiently induced by NGF in PC12 cells. PC4 cDNA is homologous to the partial sequence of a putative mouse beta-interferon and encodes a protein related to a lymphokine, the rat gamma-interferon protein. Nonetheless, PC4 appears devoid of antiviral activity. PC4 is expressed in proliferating and differentiating tissues, such as amnion, placenta, and brain at embryonic day 13.5. The relationship of PC4 to interferons and lymphokines suggests that it could play a role in regulating gene activity in the pathways induced by NGF.

Opiate and dopamine stimulate different GTPase in striatum: evidence for distinct modulatory mechanisms of adenylate cyclase.

Previous studies demonstrated that opiate inhibition of adenylate cyclase (AC) in striatal membranes is related to an opiate-stimulated GTPase with a low Km. Dopamine (DA) also dose-dependently activates a high affinity GTPase, with a pattern of stimulation and a receptor selectivity (D1 type) similar to those observed in DA activation of striatal AC. Moreover, the DA- and the opiate-sensitive GTPase activities have different sensitivities to agents that affect the inhibition of AC, such as Na+ and N-ethylmaleimide (NEM), or the stimulation, such as cholera toxin (CTX). Thus, the impairment of opiate-dependent inhibition of AC in the absence of Na+ ions or after NEM pretreatment of the membranes is parallel with preferential impairment of the opiate-dependent GTPase. On the contrary, selective blocking by CTX of the DA-dependent GTPase leads to the enhancement of AC stimulation by DA. These results suggest that DA activation of striatal AC is related to a GTPase that is specifically stimulated by DA and is associated with the Ns protein. A distinct Ni protein seems to be responsible for the opiate effect on AC and GTPase.

[Evaluation of the therapeutic efficacy of aztreonam in the treatment of infection caused by sensitive microorganisms]. / Valutazione dell'efficacia terapeutica dell'Aztreonam nel trattamento delle infezioni da microrganismi sensibili.

We report a trial in 10 patients who were given Aztreonam. Six of the patients had an infection of the respiratory system while the other four had some problems with the urinary system. All the patients presented serious infections with gram negative germs. The evaluation of the results of the trial has been carried out using laboratory and clinical data before and after the treatment. The bacterial eradication and the clinical disappearance of symptomatology has been accomplished in all cases. Therefore we can affirm that the therapeutical use of "Aztreonam" has shown its effectiveness. Its tolerance has been excellent with no side effects.

Molecular cloning of PC3, a putatively secreted protein whose mRNA is induced by nerve growth factor and depolarization.

PC3 is an immediate early gene induced by nerve growth factor in PC12 cells, a cell line derived from a tumor of the adrenal medulla that undergoes neuronal differentiation in the presence of nerve growth factor. This induction is independent of new protein synthesis as it can occur in the presence of cycloheximide. PC3 is also induced with similar kinetics, but at lower levels, by membrane depolarization (both in vivo and in vitro) and epidermal growth factor. It is induced at much lower levels by fibroblast growth factor and interleukin 6. In vivo it is found expressed in tissues, such as brain at embryonic day 13.5, placenta, amnion, and spleen, which are proliferating and/or differentiating. The deduced protein sequence from the cDNA indicates the presence of a signal peptide, suggesting that PC3 is secreted.

Overexpression of the nerve growth factor-inducible PC3 immediate early gene is associated with growth inhibition.

PC3 (pheochromocytoma cell-3) is an immediate early gene isolated as sequence induced in the rat PC12 cell line during neuronal differentiation by nerve growth factor (NGF). PC3, which is expressed in vivo in the neuroblast when it ceases proliferating and differentiates into a neuron, has partial homology with two antiproliferative genes, BTG1 and Tob. Here we report that overexpression of PC3 in NIH3T3 and PC12 cells leads to marked inhibition of cell proliferation. In stable NIH3T3 clones expressing PC3, the transition from G1 to S phase was impaired, whereas the retinoblastoma (RB) protein was detected as multiple isoforms of M(r) 105,000-115,000 (indicative of a hyperphosphorylated state) only in low-density cultures. Such findings are consistent with a condition of growth inhibition. Thus, PC3 might be a negative regulator of cell proliferation, possibly acting as a transducer of factors influencing cell growth and/or differentiation, such as NGF, by a RB-dependent pathway. This is the first evidence of a NGF-inducible immediate early gene displaying antiproliferative activity.

Denzimol, a new anticonvulsant drug. I. General anticonvulsant profile.

The anticonvulsant profile of N-[beta-[4-(beta-phenylethyl)phenyl]-beta-hydroxyethyl]imidazole hydrochloride (denzimol, Rec 15-1533) has been evaluated in mice, rats and rabbits in comparison with some standard antiepileptic drugs. Denzimol suppressed electrically and chemically induced tonic seizures but did not prevent the clonic ones. In mice and rabbits the anticonvulsant activity of denzimol against maximal electroshock seizures was almost equal to that of phenytoin and phenobarbital with more rapid onset of action, whereas in rats the compound resulted in being the most potent and the less toxic one showing a longer duration of anticonvulsant activity than phenytoin. In the maximal pentetrazol seizures test in rats denzimol showed a profile similar to that of phenytoin and carbamazepine, but different from that of barbiturates and benzodiazepines so that it is suggested that its clinical application would be that of "grand mal" and psychomotor type seizures therapy.

Possible involvement of endogenous opiates in the tolerance to the anorectic effect of fenfluramine.

Repeated administration of fenfluramine leads to a rapid and progressive loss of its effectiveness in reducing food intake. The animals tolerant to the anorectic effect of fenfluramine had markedly low basal hypothalamic serotonin (5-HT) levels. In this brain area the levels of [Met5]enkephalin-like immunoreactive material were, on the contrary, significantly higher in fenfluramine-tolerant animals than in controls. In tolerant animals the drug failed to further decrease 5-HT concentrations unless it was given at doses also reducing food intake. On the other hand, in acute experiments, morphine pretreatment potentiated and naloxone antagonized fenfluramine-induced depletion of striatal and hypothalamic 5-HT stores. In addition, when given to fenfluramine-tolerant rats, morphine restored the efficacy of the anorectic agent. After morphine pretreatment, fenfluramine depleted 5-HT and reduced food intake in tolerant animals. These findings, while further substantiating the importance of 5-HT in mediating fenfluramine anorexia, also suggest that endogenous opiates may play an important role in the processes through which tolerance to this drug develops. Fenfluramine reduces food intake by releasing 5-HT and tolerance to its anorectic effect would be a consequence of an inability to further release 5-HT. However, because release of 5-HT by fenfluramine seems to be modulated by opiates, repeated administration of fenfluramine might alter such modulatory mechanisms and tolerance to the effects of the drug would develop.

Cloning, expression and localization of human BM88 shows that it maps to chromosome 11p15.5, a region implicated in Beckwith-Wiedemann syndrome and tumorigenesis.

Porcine BM88 is a neuron-specific protein that enhances neuroblastoma cell differentiation in vitro and may be involved in neuronal differentiation in vivo. Here we report the identification, by Western blotting, of homologous proteins in human and mouse brain and the isolation of their respective cDNAs. Several human and mouse clones were identified in the EST database using porcine BM88 cDNA as a query. A human and a mouse EST clone were chosen for sequencing and were found both to predict a protein of 149 amino acids, with 79.9% reciprocal identity, and 76.4% and 70.7% identities to the porcine protein, respectively. This indicated that the clones corresponded to the human and mouse BM88 homologues. In vitro expression in a cell-free system as well as transient expression in COS7 cells yielded polypeptide products that were recognized by anti-BM88 antibodies and were identical in size to the native BM88 protein. Northern-blot analysis showed a wide distribution of the gene in human brain whereas immunohistochemistry on human brain sections demonstrated that the expression of BM88 is confined to neurons. The initial mapping assignment of human BM88 to chromosome 11p15.5, a region implicated in Beckwith-Wiedemann syndrome and tumorigenesis, was retrieved from the UniGene database maintained at the National Centre for Biotechnology Information (NCBI, Bethesda, MD, U.S.A.). We confirmed this localization by performing fluorescence in situ hybridization on BM88-positive cosmid clones isolated from a human genomic library. These results suggest that BM88 may be a candidate gene for genetic disorders associated with alterations at 11p15.5.

Inhibition of differentiation in myoblasts deprived of the interferon-related protein PC4.

PC4 (pheochromocytoma cell-4) is an immediate early gene related to IFN-gamma, the mRNA of which is induced during the course of neuronal differentiation by nerve growth factor in the PC12 cell line. Here we report that PC4 mRNA is also expressed in the myoblast C2C12 cell line and is regulated during differentiation; its expression decreases within 6 h from the onset of differentiation, attains a minimum after 12 h, and returns to basal level within 36 h. This transient down-regulation of PC4 expression in C2C12 myoblasts is prevented by transforming growth factor beta, a molecule which inhibits the differentiation of muscle. Sense and antisense PC4 cDNA transfection strategies in C2C12 cells were then used to clarify the role of PC4 in muscle differentiation. While no effect was seen by over-expression of PC4, stable transfectants underexpressing PC4 exhibited a delay in attaining the differentiated phenotype, with an impairment of myogenin and myosin expression. Myogenin was also inhibited in C2C12 cells microinjected with the anti-PC4 polyclonal antibody A451. We thus postulate a role for PC4 as a positive regulator during muscle differentiation.