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Biomedical subjects

R Scotti

Publications and source records attributed to R Scotti.

At least 19 recordsLinked to original sources
PubMed2006

The prosthetically guided osteodistraction of the mandible in the microvascular bone reconstruction after cancer surgery.

The rehabilitation of the mandible after ablation cancer surgery is a challenge. Furthermore, osteodistraction in the microvascular fibula flap makes it difficult to predict adequate bone lengthening. The aim of this article is to evaluate a protocol used to manufacture templates for measuring osteodistraction, in terms of force vectors and definitive height. An accurate prosthetic wax-up with guide pins measuring the quantity of bone lengthening must be performed to manufacture the template. This device may be used to establish the end of the osteo-distraction in respect to the vertical dimension of the definitive occlusion.

Adolescent↗
PubMed2006

Early biofilm colonization on polished- and glazed-zirconium ceramic surface. Preliminary results.

AIM: The purpose of this study was to evaluate the effect of ceramic surface polishing procedure on the early dental biofilm formation on zirconium ceramics. METHODS: Twenty samples (discs shape) of tetragonal zirconium polycrystal stabilized with yttrium ceramics (Y-TZP) for LAVA system were fabricated (5 mm diameter and 1.5 mm thickness). Two patients with high level of dental hygiene were selected for this study. Oral devices covering the crowns of the upper premolars and molars were fabricated for each participant. Glazed and polished samples of Y-TZP ceramics were fixed on the vestibular and palatal zones of the devices. After 20 min (8 samples) and 1 h (8 samples) in the oral environment, the samples were removed and analyzed in a scanning electron microscope. The surface topographies of 4 ceramic samples (2 glazed and 2 polished) were analyzed (control group: without exposition in oral environment). RESULTS: The glazed samples showed a more irregular surface than polished samples. Deposition of granular aggregates was verified on all the samples in the two times of the study analyzed. This granular material coated more intensely on irregular areas, and its thickness increased after 1 h. No difference was observed as to bacterial morphology in any time of the study. Cocci and rods-shaped prevailed. CONCLUSIONS: Glazed surfaces presented larger tendency to dental biofilm accumulation.

Adult↗
PubMed2004

Neuroradiologic differential diagnosis of cerebral intraparenchymal hemorrhage.

Cerebral intraparenchymal hematoma (IH) is one of the most common causes of sudden onset of focal neurologic deficit. This is particularly true in the acute phase, in which IH appears hyperdense compared to the cerebral tissue. By three to four weeks, it becomes isodense with the cerebral gray matter and hypodense within 2 to 6 months. After contrast media administration, IH shows a peripheral ring of enhancement owing to the breakdown of the blood brain barrier. On magnetic resonance imaging (MRI), the appearance of IH depends upon the paramagnetic effects of the different derivates of hemoglobin and both the magnetic field strength and type of sequences used. In the hyperacute phase, IH appears hyperintense on T2 and hypointense on T1 owing to the presence of oxyhemoglobin. In the acute phase, IH is hypointense on T2 and iso-hypointense on T1 as a consequence of the presence of deoxyhemoglobin, which is converted into methemoglobin by 3 to 5 days. Methemoglobin has a strong paramagnetic effect, so in this phase IH becomes hyperintense on T1 and hypointense on T2. After 2 weeks, methemoglobin is converted in hemosiderin, responsible of the ring of hypointensity surrounding the lesion on T2WI. When an IH has been diagnosed, someone should think about the origin of bleeding. Among the different differential diagnosis, one should think about the possible origin, taking into account some parameters, such as: anamnestic data, site of the lesion, number of lesions, appearance on CT and MRI, and presence of perilesional edema. Computed tomography is a reliable and very fast tool for the diagnosis of IH, but MRI is able to provide additional information about the spontaneous or secondary nature of the hematoma, thus allowing a better characterization of the hemorrhagic lesion.

Brain Edema↗
PubMed2004

Home care maintenance protocol for ear prostheses.

Hygienic home care maintenance for patients who have received a maxillofacial prosthesis is very important in order to secure a long-term success of a facial rehabilitation. Craniofacial implant therapy requires a specific protocol to care for the peri-implant tissues and material used for the prosthesis. This article presents the maintenance and care protocol for proper follow-up management of a maxillofacial ear prosthesis. Home care methods for the prosthesis hygiene are described, including: the insertion and the disconnection of the ear prosthesis, hygiene of the bar abutments before and after postdefinitive connection to the craniofacial fixtures, washing of the device, professional follow-up.

Humans↗
PubMed2003

[Overdenture supported by natural teeth: analysis of clinical advantages].

Hybrid prosthesis supported by natural teeth (overdenture) is widely used in clinical practice and should be executed whenever the clinical conditions suggest it. Through a critical review of the literature, the anatomical, functional, psychological and clinical advantages are emphasized. Among the first ones, the prophylaxis of residual anatomical components, due to the limitation of bone resorption, and the preservation of sensorial proprioception are relevant. Important advantages are also represented by a better crown-root ratio of residual teeth supporting overdenture, with the consequent improvement of the longitudinal prognosis of such teeth. The greater retention and stability of overdenture in comparison with complete denture greatly improve the masticatory efficacy. The psychological advantages resulting from the dental anchorage, which allows the patient to be more confident in social life, are also relevant. Finally, when the dental support is lost, converting overdenture into complete denture is simple and quick, and makes easier the longitudinal clinical maintenance of the denture.

Bone Resorption↗
PubMed2003

[New aesthetic results with auricular prosthesis: two case reports].

The extrinsic and intrinsic coloration of maxillo-facial silicone elastomers has always been a challenge for the clinician in order to obtain a perfect, durable integration with the surrounding skin tissues. This preliminary report describes the method for obtaining good aestethetic results for maxillo-facial prosthesis. This study shows the aesthetic results of a new silicone for the laboratory technique of creating color of the basis for a maxillo-facial prosthesis, with a good matching with human skin. The technique is useful for the direct extrinsic coloration of the surface onto the skin of the patient by means of the RTV version of the same silicone. The technological properties of this material also make it easy to reproduce the emerging profile of the prosthesis from the human skin, avoiding anaesthetic overcounturings. The 12 month follow-up shows excellent and stable aesthetic results, which are not influenced by home care procedures and by the weathering effect on color and on physical properties.

Adult↗
PubMed2001

Slow diffusion of home HIV-specimen collection: provider concerns at odds with client preferences.

BACKGROUND: Home specimen collection and telephone counseling (HSCTC) may be a convenient new method for detection of HIV infection among cohorts at high-risk for HIV. GOAL: To evaluate attitudes about HSCTC among participants, HIV counselors, and community advisory board members associated with a national multisite study of persons at high risk for HIV. STUDY DESIGN: Twelve focus groups and surveys were conducted at six sites among 126 counselors, community advisory board members, and cohort participants. RESULTS: Staff and community advisory board members raised concerns about the acceptability, feasibility, safety, and effectiveness of HSCTC. In contrast, participants (92%) reported a willingness to collect blood and oral samples on a frequent basis, and preferred telephone (73%) to office-based counseling. CONCLUSION: Home specimen collection and telephone counseling appear to be preferred by study participants at high risk of HIV infection. Staff and community advisory board members had stronger reservations than prospective users.

Adolescent↗
PubMed2001

What is community? An evidence-based definition for participatory public health.

Increased emphasis on community collaboration indicates the need for consensus regarding the definition of community within public health. This study examined whether members of diverse US communities described community in similar ways. To identify strategies to support community collaboration in HIV vaccine trials, qualitative interviews were conducted with 25 African Americans in Durham, NC; 26 gay men in San Francisco, Calif; 25 injection drug users in Philadelphia, Pa; and 42 HIV vaccine researchers across the United States. Verbatim responses to the question "What does the word community mean to you?" were analyzed. Cluster analysis was used to identify similarities in the way community was described. A common definition of community emerged as a group of people with diverse characteristics who are linked by social ties, share common perspectives, and engage in joint action in geographical locations or settings. The participants differed in the emphasis they placed on particular elements of the definition. Community was defined similarly but experienced differently by people with diverse backgrounds. These results parallel similar social science findings and confirm the viability of a common definition for participatory public health.

AIDS Vaccines↗
PubMed2000

Targeted terminal deletions as a tool for functional genomics studies in Plasmodium.

We describe a transfection system that induces terminal deletions at specific chromosome ends in malaria parasites using a linear construct containing telomeric repeats at one end and plasmodial sequences able to drive homologous recombination at the other. A site-specific deletion was generated at one extremity of chromosome 5 of Plasmodium berghei, which was stably maintained in the parasite population selected after transfection. The telomeric repeat array introduced with the construct reached the average length observed in natural telomeres of Plasmodium, indicating that in vivo telomere addition occurred at the newly formed extremity. The expression of a mutant dhfr/ts gene conferring pyrimethamine resistance, used as a selectable marker, was not affected by the proximity to the telomeric sequences, either in the presence or absence of drug pressure. In addition, no transcriptional silencing was observed on insertion of the mutant dhfr/ts gene either in subtelomeric or internal positions that are transcriptionally silent in blood-stage parasites. This suggests that the activity of its promoter is not affected by the chromatin organization of the chromosomal context.

Animals↗
PubMed2000

[Localized lymph node lymphangiomyoma. Description of 2 cases].

Lymphangioleiomyomatosis is a rare disease characterized by an immature-appearing smooth muscle proliferation in the lung and along axial lymphatics. Rarely it is limited to lymph nodes, without extranodal disease. Two cases of localized nodal lymphangiomyoma in a 48 and 54 year-old women are presented: in both cases the lesion was limited to pelvic lymph nodes and it was an incidental finding during staging for tumours of the gynaecological tract.

Carcinoma, Endometrioid↗
PubMed1999

The putative gene for the first enzyme of glutathione biosynthesis in Plasmodium berghei and Plasmodium falciparum.

The putative gene for gamma-glutamylcysteine synthetase, the rate-limiting enzyme in glutathione biosynthesis, has been characterized both in Plasmodium berghei and Plasmodium falciparum. Protein sequence comparison between these two species reveals large conserved regions sharing more than 80% similarity, separated by less conserved portions. When the comparison is extended to known gamma-glutamylcysteine synthetases from other eukaryotes, a number of high similarity blocks are observed which may help in identifying sequence essential for protein function.

Amino Acid Sequence↗
PubMed1999

[Sclerosing mucoepidermoid carcinoma with eosinophilia of the thyroid: description of a case].

INTRODUCTION: A case of sclerosing mucoepidermoid carcinoma with eosinophilia of the thyroid gland is described. RESULTS: The patient, a 32 year-old female with Hashimoto's thyroiditis, presented with a 4 cm nodule of the right lobe of the thyroid gland. The tumour was constituted by squamoid cords infiltrating a dense fibro-jaline stroma rich in eosinophils. The patient is alive and well 14 months after surgery. DISCUSSION: The literature is briefly reviewed and the differential diagnosis is discussed. In the Author's opinion, sclerosing mucoepidermoid carcinoma with eosinophilia of the tyroid is a well defined clinicopathological entity.

Adult↗
PubMed1999

Genome plasticity and sexual differentiation in Plasmodium.

Spontaneous subtelomeric deletions of Plasmodium chromosomes have been observed both in natural infections and in laboratory maintained parasites. In the latter case, functions dispensable for asexual parasite multiplication and encoded at the extremities of the chromosomes are easily lost. In particular, spontaneous subtelomeric deletions have been characterised which affect gametocytogenesis both in Plasmodium berghei maintained in laboratory animals and in Plasmodium falciparum propagated in in vitro cultures. In order to identify these genetic determinants, and, potentially, other genes located subtelomerically, we designed a transfection system able to induce and select for controlled, site-specific subtelomeric deletions.

Animals↗
PubMed1998

Comparative study of the marginal microleakage of six cements in fixed provisional crowns.

STATEMENT OF PROBLEM: In many situations, provisional restorations require a long-term permanence in the oral cavity. During this period, the abutments need the best possible biologic and mechanical protection. In this way, the vitality of the pulp and the integrity of mineralized tissues can be preserved. The luting cement used to fix interim restorations should have good mechanical properties, low solubility, and good adhesion to resist bacterial and molecular penetration. However, because of its provisional nature, the prosthesis should be easy to remove from the abutments. These contrasting requirements may lead to a compromise in cement behavior, particularly in its mechanical properties. PURPOSE: This in vitro study evaluated the marginal microleakage of 4 provisional cements, a cavity base compound and a zinc-phosphate luting cement in provisional acrylic resin crowns fixed on extracted human teeth. MATERIAL AND METHODS: Thirty acrylic resin crowns were made and fitted on intact human premolars with the 6 cements. All restorations were applied in a standardized manner by means of an axial load of 10 kg. Specimens were thermocycled then submerged in a 5% basic fuchsin solution, then sectioned and observed under a light stereomicroscope. A 5-level scale was used to score dye penetration in the tooth/cement interface. RESULTS: A high dye penetration in the tooth/cement interface was present in all 4 provisional cements. Microleakage existed in specimens where zinc-phosphate and cavity base compounds were used; however, it was lower than the other materials. A significant difference (P < .05) was found between zinc-phosphate and one eugenol-free cement and between cavity base and the same eugenol-free cement. CONCLUSIONS: All materials tested demonstrated different degrees of microleakage. Zinc-phosphate and cavity base compound cements had the best sealing properties. This latter, even if conceived as a cavity base, may be considered a good provisional cement as far as microleakage is concerned.

Acrylic Resins↗
PubMed1998

[Heat-induced symptomatology in human teeth. An in-vitro study].

OBJECTIVE: Various dental procedures can generate thermal increase in the dental pulp, in particular if they are incorrectly conducted. In literature the pulp cells are considered very heat sensitive. In this study the symptomatological response of patients during and after thermal administration to the dental crown has been recorded. The analysis of the symptomatology was used as an indication for the definition of the threshold of thermal damage. EXPERIMENTAL DESIGN: Twelve healthy teeth of four patients programmed for extraction were subdivided into six couples of homologous teeth. One tooth out of each couple was used for the immediate in vivo recording of the symptoms; the other, once extracted, was used to determine the thermal increase applied through the insertion of a thermocouple sensor. In each couple of teeth the thermal stimulus was equal. RESULTS: The average thermal increase was 11.2 degrees C. Pain starts at temperatures ranging from 39.5 to 50.4 degrees C with an average of 44.6 degrees C. This agrees with classical physiological data which reports the threshold of pain at 45 degrees C. CONCLUSIONS: The threshold of pain registered suggests that at temperatures below 44.6 degrees C damage to the dental pulp is improbable, at least in healthy teeth. The limit of 45 degrees C appears, therefore, to be a probable safe threshold, contrary to what is reported in literature.

Adolescent↗
PubMed1998

[The construction of plates for intraoral registration with photopolymerizing resins. An original method].

The recording of maxillo-mandibular relationships using Gothic arch assembly in dentulous subjects is useful not only in prosthetic rehabilitation, but also in the analysis of mandibular range of motion on patients with temporomandibular disorders. The traditional methodology to assemble Gothic arch plate is too long and elaborate, so it is remitted to the laboratory. This study describes a quick and simplified technique utilizing photopolymerizing resins which can be used by the dentist in his own office, in order to permit a greater use in the clinical practice.

Equipment Design↗
PubMed1997

Clinical and histological evaluation of thermal injury thresholds in human teeth: a preliminary study.

The effect on healthy dental pulp of thermal increases ranging from 8.9 to 14.7 degrees C was evaluated. These temperature increases correspond approximately to those caused by certain restorative procedures, such as tooth preparation with high-speed instruments and the fabrication of direct provisional crowns. Two criteria of evaluation have been used in conjunction, a clinical (symptomatic) and a histological one, to assert with greater precision potential damage to the pulp. The results suggest a low susceptibility of cells to heat, which does not appear to be a major factor of injury, at least in the short term. The main cause of postoperative inflammation or necrosis of the pulp is probably the injury of the dentine, a tissue in direct functional and physiological connection with the pulp.

Adolescent↗