Biomedical subjects

A Toffanin

Publications and source records attributed to A Toffanin.

15 recordsLinked to original sources

PubMed2006

Investigation into the role of the truncated denitrification chain in Rhizobium sullae strain HCNT1.

Most denitrifying bacteria reduce nitrate to the inert gases nitrous oxide or nitrogen. A remarkable exception to this is Rhizobium sullae strain HCNT1, which catalyses only a single step in the denitrification pathway, the reduction of nitrite to the reactive molecule nitric oxide. Further study demonstrated that HCNT1 does not encode the genes for NO reductase. Prolonged incubation of HCNT1 under anoxic conditions revealed that the cells had reduced culturability but not viability when nitrite was present. This may indicate an adaptation to anoxic conditions to provide resistance to environmental stresses. A closely related strain of R. sullae, strain CC1335, which is unable to denitrify, was found to lose culturability but not viability irrespective of the presence of nitrite. When the gene for nitrite reductase was mobilized into CC1335, this increased culturability with or without nitrite. These results indicate that the presence of nitrite reductase can influence the long-term survival of R. sullae strains and may provide an explanation as to why HCNT1 possesses this unusual truncation of its denitrification electron transport chain.

Cell Survival↗

PubMed2004

Gemination of maxillary incisors.

Gemination is defined as a shape anomaly of teeth caused by an incomplete division of a single tooth bud. Its aesthetic and functional implications usually require a complex endodontic, restorative, periodontal, surgical, and orthodontic treatments. Three cases of gemination of maxillary incisors, resolved by different therapeutic approaches, are reported. The 1st case (germination of 2.1) was resolved by a simple crown-plasty. The 2nd case (gemination of 1.1 and 2.1) was resolved by a crown-plasty of 2.1 and an interradicular section of 1.1 with extraction of lateral root. The 3rd case (2.2 supernumerary and gemination of 1.2) was resolved by sacrifice of 1.2, extraction of 2.2 and its implantation in 1.2 region. In order to obtain an acceptable aesthetic and functional restoration, as in the cases presented, a good team-work, where all the specialists contribute to the selection of the more suitable treatment possible, is mandatory.

Adult↗

PubMed2002

Intracranial dislocation of the mandibular condyle: report of two cases and review of the literature.

Fractures of the mandibular condylar process are common and account for up to 40% of all mandibular fractures. Penetration of the condylar head into the middle cranial fossa is, however, rare. We have found reports of only 43 cases since 1834. The diagnosis of intracranial condylar dislocation is difficult, there are usually no particular symptoms or neurological signs. As a result, detailed radiological studies are necessary. In the absence of clear radiographic images of the condylar structures, computed tomography (CT) is essential to locate the fragments and to investigate and monitor intracranial lesions. This paper describes the diagnostic and surgical procedures used in two cases of condylar dislocation and discusses them with reference to previous cases. The use of a titanium screw, which was positioned intracranially in the first case, has not, to our knowledge, been described previously.

Bone Plates↗

PubMed2000

Familial florid cemento-osseous dysplasia: a case report.

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Adolescent↗

PubMed1997

Analysis of the role of the nnrR gene product in the response of Rhodobacter sphaeroides 2.4.1 to exogenous nitric oxide.

Rhodobacter sphaeroides 2.4.1, which is incapable of denitrification, has been found to carry nnrR, the nor operon, and nnrS, which are utilized for denitrification in R. sphaeroides 2.4.3. The gene encoding nitrite reductase was not found in 2.4.1. Expression of beta-galactosidase activity from a norB-lacZ fusion was activated when cells of 2.4.1 were incubated with NO-producing bacteria. This result indicates that the products of nnrR and the genes flanking it are utilized when 2.4.1 is growing in an environment where denitrification occurs.

Amino Acid Sequence↗

PubMed1996

Electrocatalytic reduction of nitric oxide at electrodes modified with electropolymerized films of [Cr(v-tpy)2]3+ and their application to cellular NO determinations.

Nitric oxide can be electrocatalytically reduced at electrodes modified with electropolymerized films of [Cr(v-tpy)2]3+. Upon further modification with a thin film of Nafion (to prevent interferences from anions, especially nitrite), these electrodes can be employed as NO sensors in solution with submicromolar detection limits and fast response. We have carried out preliminary studies of cellular NO release from Rhodobacter sphaeroides bacterial cells with excellent results.

Catalysis↗

PubMed1996

Characterization of the gene encoding nitrite reductase and the physiological consequences of its expression in the nondenitrifying Rhizobium "hedysari" strain HCNT1.

Rhizobium "hedysari" HCNT1 is an unclassified rhizobium which contains a nitric oxide-producing nitrite reductase but is apparently incapable of coupling the reduction of nitrite to energy conservation. The gene encoding the nitrite reductase, nirK, has been cloned and sequenced and was found to encode a protein closely related to the copper-containing family of nitrite reductases. Unlike other members of this family, nirK expression in HCNT1 is not dependent on the presence of nitrogen oxides, being dependent only on oxygen concentration. Oxygen respiration of microaerobically grown Nir-deficient cells is not affected by concentrations of nitrite that completely inhibit oxygen respiration in wild-type cells. This loss of sensitivity suggests that the product of nitrite reductase, nitric oxide, is responsible for inhibition of oxygen respiration. By using a newly developed chemically modified electrode to detect nitric oxide, it was found that nitrite reduction by HCNT1 produces significantly higher nitric oxide concentrations than are observed in true denitrifiers. This indicates that nitrite reductase is the only nitrogen oxide reductase active in HCNT1. The capacity to generate such large concentrations of freely diffusible nitric oxide as a consequence of nitrite respiration makes HCNT1 unique among bacteria.

Amino Acid Sequence↗

PubMed1994

[The Gorlin-Goltz syndrome. A report of 2 cases].

Two cases of patients with Gorlin-Goltz syndrome are described. The Gorlin-Goltz syndrome is a polydistrectual, hereditary disease characterized by multiple keratocysts and basocellular nevomatosis. It is pointed out that the inconstancy of the main symptoms makes early diagnosis difficult. The histologic characteristics of odontogenic keratocysts and the possible etiopathogenetic relations between cystic lesions and hamartia of adjacent oral mucosa, as considered by Stoelinga, are also discussed. In view of the course of the cases presented, a surgical approach considering such potential findings, is supposed to favorably affect the clinical evolution in respect to a high relapsing drift.

Adult↗

PubMed1984