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Biomedical subjects

E Marcantonio

Publications and source records attributed to E Marcantonio.

At least 19 recordsLinked to original sources
PubMed2004

Effect of cyclosporin A on alveolar bone homeostasis in a rat periodontitis model.

OBJECTIVES: The administration of cyclosporin A has been associated with significant bone loss and increased bone remodeling. The present investigation was designed to evaluate the effects of cyclosporin A on alveolar bone of rats subjected to experimental periodontitis, using serum, stereometric and radiographic analysis. METHODS: Twenty-four rats were divided into one of the following groups with six animals each: group I, control rats; group II, in which the animals received a cotton ligature around the lower first molars; group III, in which the rats received a cotton ligature around the lower first molars and were treated with 10 mg/(kg body weight day) of cyclosporin A; group IV, in which the rats were treated with 10 mg/(kg body weight day) of cyclosporin A. At the end of experimental period, at 30 days, animals were killed and the serum calcium and alkaline phosphatase levels were measured in all groups. The distance from the alveolar bone crest to the cemento-enamel junction was measured radiographically for each mesial surface of the lower first molars of each rat. After histological processing, the stereological parameters: volume densities of multinucleated osteoclasts (V(o)), alveolar bone (V(b)), marrow (V(m)), and relation of eroded surface/bone surface (Es/Bs) were assessed at the mesial region of the alveolar bone. RESULTS: Significant decreases in serum calcium were observed in those groups that received cyclosporin A therapy. No significant changes in serum alkaline phosphatase were observed. The therapy with cyclosporin A combined with the ligature placement decreased the V(b) and increased the V(o), V(m) and Es/Bs at the mesial surface of lower first molars. On the other hand, the radiographic data showed that cyclosporin A therapy diminished the alveolar bone loss at the mesial surface of the lower first molars. CONCLUSIONS: Therefore, within the limits of this study, we suggest that cyclosporin A at immunosuppressive levels can bring about an imbalance in the alveolar bone homeostasis in rats. However, in the presence of inflammatory stimulation, the inhibition of the immune system by cyclosporin A may decrease the initial periodontal breakdown.

Alkaline Phosphatase↗
PubMed2001

Impact of age on perioperative complications and length of stay in patients undergoing noncardiac surgery.

BACKGROUND: Major surgical procedures are performed with increasing frequency in elderly persons, but the impact of age on resource use and outcomes is uncertain. OBJECTIVE: To evaluate the influence of age on perioperative cardiac and noncardiac complications and length of stay in patients undergoing noncardiac surgery. DESIGN: Prospective cohort study. SETTING: Urban academic medical center. PATIENTS: Consecutive sample of 4315 patients 50 years of age or older who underwent nonemergent major noncardiac procedures. MEASUREMENTS: Major perioperative complications (cardiac and noncardiac), in-hospital mortality, and length of stay. RESULTS: Major perioperative complications occurred in 4.3% (44 of 1015) of patients 59 years of age or younger, 5.7% (93 of 1646) of patients 60 to 69 years of age, 9.6% (129 of 1341) of patients 70 to 79 years of age, and 12.5% (39 of 313) of patients 80 years of age or older (P < 0.001). In-hospital mortality was significantly higher in patients 80 years of age or older than in those younger than 80 years of age (0.7% vs. 2.6%, respectively). Multivariate analyses indicated an increased odds ratio for perioperative complications or in-hospital mortality in patients 70 to 79 years of age (1.8 [95% CI, 1.2 to 2.7]) and those 80 years of age or older (OR, 2.1 [CI, 1.2 to 3.6]) compared with patients 50 to 59 years of age. Patients 80 years of age or older stayed an average of 1 day more in the hospital, after adjustment for other clinical data (P = 0.001). CONCLUSIONS: Elderly patients had a higher rate of major perioperative complications and mortality after noncardiac surgery and a longer length of stay, but even in patients 80 years of age or older, mortality was low.

Age Factors↗
PubMed2001

A study of histological responses from Ti-6Al-7Nb alloy dental implants with and without plasma-sprayed hydroxyapatite coating in dogs.

Titanium alloys are hoped to be used much more for applications as implant materials in the medical and dental fields because of their basic properties, such as biocompatibility, corrosion resistance and specific strength compared with other metallic implant materials. Thus, the Ti-6Al-7Nb alloy that has recently been developed for biomedical use, that is, primarily developed for orthopaedic use, is to be studied in this paper, for application in dental implants. The biocompatibility test in vivo was carried out in dogs and the osseointegration was verified through histological analysis of the samples of the Ti-6Al-7Nb alloy with and without hydroxyapatite coating that were inserted in the alveoli. Within the controlled conditions the samples did not show any toxic effects on the cells.

Journal Article↗
PubMed2000

Regeneration of Class III furcation defects with basic fibroblast growth factor (b-FGF) associated with GTR. A descriptive and histometric study in dogs.

BACKGROUND: The poor predictability of periodontal regenerative treatment of Class III furcation defects stimulates the study of alternatives to improve its results, such as the use of polypeptide growth factors. The objective of this study was to evaluate, both histologically and histometrically, the effects of topical application of basic fibroblast growth factor (b-FGF) associated with guided tissue regeneration (GTR) in the treatment of Class III defects surgically induced in dogs. METHODS: All second and fourth premolars of 5 mongrel dogs were used and randomly assigned to one of three treatment groups: group 1 (control), treated with scaling and root planing, tetracycline hydrochloride (125 mg/ml) conditioning, and GTR with a collagen membrane; group 2, same treatment as group 1 plus 0.5 mg of b-FGF; group 3, same treatment as group 1 plus 1.0 mg of b-FGF. After a 90-day healing period, routine histologic processing and staining with hematoxylin and eosin and Masson trichrome were performed. RESULTS: The descriptive analysis indicated better regenerative results in both groups treated with b-FGF while the histometric data, analyzed by means of analysis of variance (ANOVA), showed greater filling of the defects in group 2 in comparison to the defects in groups 3 and 1, respectively, which was represented by a smaller area of plaque-occupied space (P = 0.004) as well as a greater amount of newly formed cementum (P = 0.002). CONCLUSIONS: These results indicate that b-FGF, especially in smaller doses, may enhance the regenerative results in Class III furcation lesions, leading to greater filling of these defects with both mineralized and non-mineralized tissues.

Analysis of Variance↗
PubMed2000

Treatment of gingival recession: comparative study between subepithelial connective tissue graft and guided tissue regeneration.

BACKGROUND: Various procedures have been proposed to treat gingival recession, but few studies compare these procedures to each other. The purpose of this study was to evaluate a clinical comparison of subepithelial connective tissue graft (SCTG) and guided tissue regeneration (GTR) with a collagen membrane in the treatment of gingival recessions in humans. METHODS: Twenty-four defects were treated in 12 patients who presented canine or pre-molar Miller Class I and/or II bilateral gingival recessions. Both treatments were performed in all patients, and clinical measurements were obtained at baseline and 18 months after surgery. These clinical measurements included gingival recession height (GR), root coverage (RC), probing depth (PD), keratinized tissue width (KT), and final esthetic result. RESULTS: Both SCTG and GTR with a bioabsorbable membrane and bone graft demonstrated significant clinical and esthetic improvement for gingival recession coverage. The SCTG group was statistically significantly better than GTR for height of GR (SCTG = 0.2 mm, GTR = 1.12 mm, P= 0.02) and KT (SCTG = 4.58 mm, GTR = 2.5 mm, P<0.0001). However, PD was statistically significantly better for GTR than SCTG treatment (GTR = 1.66 mm, SCTG = 1.00, P= 0.01). The 2 procedures were statistically similar in root coverage (SCTG = 95.6%, GTR = 84.2%, P= 0.073). The esthetic condition after both treatments was satisfactory (P= 0.024). CONCLUSIONS: It was concluded that the gingival recessions treated with the SCTG group were superior for GR, RC, and KT clinical parameters, while GTR demonstrated better PD reduction. The final esthetic results were similar using both techniques.

Absorbable Implants↗
PubMed1999

Biocompatibility studies of anionic collagen membranes with different degree of glutaraldehyde cross-linking.

The work describes the biocompatibility and biodegradation studies of anionic collagen membranes casted form collagen gels collagen, that were selective hydrolyzed at the carboxyamide groups, as a function of the degree of cross-links induced by glutaraldehyde. Independently from the degree of cross-links, all membranes studied were characterized by a similar inflammatory response, inversely dependent on glutaraldehyde reaction time, that decreased from the time of the implant. Cell alterations, mineralization or contact necrosis were not observed in any of the membranes studied. Rates for membrane tissue biodegradation were directly related to glutaraldehyde reaction time, and ranged from 30 to periods longer than 60 days, associated with good biocompatibility. Although other properties must be considered, their use in the treatment of periodontal diseases, the biological behavior observed with the 8 h GA cross-linked membrane suggests that, anionic collagen membrane described in this work may be of potential use, not only in association with guided tissue regeneration technique for periodontal tissue reconstruction, but also in other collagen biomaterial applications where controlled biodegradability is required.

Animals↗
PubMed1997

Evaluation of anionic collagen membranes in the treatment of class II furcation lesions: an histometric analysis in dogs.

This study aims to evaluate the effect of using anionic collagen membranes in guided tissue regeneration treatment of Class II furcation lesions in dogs. The defects were created in the buccal furcation of 16 mandibular premolars of four dogs. After 56 days without plaque control, the sites were scaled and divided into two groups according to the treatment applied: control sites, open flap debridement; and test sites, guided tissue regeneration treatment. The animals were killed after 3 months. Histological and histometrical analyses showed that the collagen membrane was better than open flap debridement in terms of newly formed cementum and epithelial migration prevention. It provided effective blockade of epithelial tissue and promoted regeneration of lost periodontal tissues, suggesting that the membrane warrants further study.

Animals↗
PubMed1993

Psychological evaluation of patients scheduled for orthognathic surgery.

Using a questionnaire, 41 patients scheduled for orthognathic surgery were evaluated pre- and postoperatively to determine some of their psychological characteristics and treatment outcome from the patient's standpoint. Among other conclusions, the results showed that some patients may not fully understand the details of their deformity, despite a full explanation by the orthodontist and surgeon. Expectations regarding treatment outcome may be unrealistic even in patients with valid self-motivation for surgery. Social adjustment usually improves after treatment. Functional changes were noticed by over 80% of the patients and esthetic changes in over 90%.

Adolescent↗
PubMed1993

Allogeneic transplants of rib cartilage preserved in 98% glycerol or 70% alcohol into the malar process of rats: a comparative histological study.

A comparative study was made of two methods of cartilage preservation, 98% glycerol and 70% alcohol. Rib cartilage was treated by either of these methods and transplanted into the malar process of rats. Cartilage grafts preserved by both methods were equally well tolerated. Resorption and bone substitution were similar in both groups after 120 days, although resorption was greater for the alcohol-preserved cartilage up until day 30. The possible reduction in antigenicity by the 98% glycerol did not produce any difference of behavior from the cartilage preserved in 70% alcohol.

Animals↗
PubMed1990

Autogenous transplantation of rib cartilage preserved in glycerol, after removal of the perichondrium, to the malar process of rats--a histological study (Part I).

Seventy-two male albino rats received autogenous transplants of glycerol-preserved rib cartilage into the malar process. The animals were divided into two groups which received preserved cartilage with or without perichondrium. The implants were well tolerated and removal of the perichondrium enhanced the rate of resorption and bone replacement of the material.

Animals↗
PubMed1987

Isolation and characterization of cDNA clones for rat ribophorin I: complete coding sequence and in vitro synthesis and insertion of the encoded product into endoplasmic reticulum membranes.

Ribophorins I and II are two transmembrane glycoproteins that are characteristic of the rough endoplasmic reticulum and are thought to be part of the apparatus that affects the co-translational translocation of polypeptides synthesized on membrane-bound polysomes. A ribophorin I cDNA clone containing a 0.6-kb insert was isolated from a rat liver lambda gtll cDNA library by immunoscreening with specific antibodies. This cDNA was used to isolate a clone (2.3 kb) from a rat brain lambda gtll cDNA library that contains the entire ribophorin I coding sequence. SP6 RNA transcripts of the insert in this clone directed the in vitro synthesis of a polypeptide of the expected size that was immunoprecipitated with anti-ribophorin I antibodies. When synthesized in the presence of microsomes, this polypeptide, like the translation product of the natural ribophorin I mRNA, underwent membrane insertion, signal cleavage, and co-translational glycosylation. The complete amino acid sequence of the polypeptide encoded in the cDNA insert was derived from the nucleotide sequence and found to contain a segment that corresponds to a partial amino terminal sequence of ribophorin I that was obtained by Edman degradation. This confirmed the identity of the cDNA clone and established that ribophorin I contains 583 amino acids and is synthesized with a cleavable amino terminal insertion signal of 22 residues. Analysis of the amino acid sequence of ribophorin I suggested that the polypeptide has a simple transmembrane disposition with a rather hydrophilic carboxy terminal segment of 150 amino acids exposed on the cytoplasmic face of the membrane, and a luminal domain of 414 amino acids containing three potential N-glycosylation sites. Hybridization measurements using the cloned cDNA as a probe showed that ribophorin I mRNA levels increase fourfold 15 h after partial hepatectomy, in confirmation of measurements made by in vitro translation of liver mRNA. Southern blot analysis of rat genomic DNA suggests that there is a single copy of the ribophorin I gene in the haploid rat genome.

Amino Acid Sequence↗
PubMed1978

A contribution to the histological study of hypercementosis using metal staining.

After studying hypercementosis, in detail using metallic staining procedures, the authors reached the following conclusions: (1) The histology of hypercementosis, observed by metallic staining reveals remarkable and characteristic microscopical alterations. (2) The Rio Hortega12 procedures, the mitochondria technique of Polak,10 and the method of Achucarro-Hortega13 are of great value for the study of the morphology of cementum. (3) Among the technical procedures used, we consider the 1916 method of Achucarro-Hortega as affording the best view of cementocytes. (4) The Sharpey fibers, revealing great irregularity in course, shape and size, and frequent interruptions could be clearly observed; heavily stained lacunae were frequently observed along the cementum-dentin border; a direct deposit of cellular cementum on the dentin in the middle third of the root was frequently observed. Curiously, an acellular cementum deposit next to a cellular cementum layer could be observed; we also noted numerous cementocytes of different shapes and sizes, at times exhibiting alterations of a degenerative type, particularly fragmentation of protoplasmic prolongations. (5) The techniques used also showed the frequency of blood vessels in the texture of hyperplastic cementum and the presence of capillaries near cementum-dentin junction.

Collagen↗