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Biomedical subjects

C Tinti

Publications and source records attributed to C Tinti.

At least 19 recordsLinked to original sources
PubMed2001

Long-term evaluation of osseointegrated implants inserted at the time or after vertical ridge augmentation. A retrospective study on 123 implants with 1-5 year follow-up.

The purpose of the present study was to evaluate retrospectively, after 1 to 5 years of prosthetic loading, 123 implants consecutively inserted at the time of vertical ridge augmentation in 4 clinics. At the time of the implant surgery, 3 different techniques were used: the implants were allowed to protrude 2 to 7 mm from the bone level and a titanium reinforced expanded-polytetrafluoroethylene (e-PTFE) membrane was positioned to protect either the blood clot (Group A, 6 patients), or an allograft (Group B, 11 patients), or an autograft (Group C, 32 patients). The annual implant evaluation was carried out according to a standard protocol utilized for long term studies with endosseous implants inserted in non-regenerated bone. Only 1 implant failed immediately after the second stage surgery and after 1 month it was substituted with a new implant. All the remaining implants appeared clinically stable, no signs of radiolucency were present at the bone-implant interface, therefore, they could be defined successfully osseointegrated. The radiographic analysis showed stable bone crest levels with a mean bone loss of 1.35 mm for the Group A, of 1.87 mm for the Group B and of 1.71 for the Group C during the period of observation. Only 2 implants demonstrated an increased crestal bone loss of 3.5 mm and 4 mm respectively at the first year examination. On the base of these results, we can confirm previous long term studies on regenerated bone and we can conclude that vertically augmented bone with GBR techniques responds to implant placement like native, non-regenerated bone.

Adult↗
PubMed2001

A bioresorbable barrier in the treatment of gingival recession: description of a new resorbable dome device.

The biologic principle of guided tissue regeneration has been expanded to mucogingival surgery, using resorbable barrier membranes for the treatment of gingival recessions. Space provision is one of the main problems in non-space making defects, considering the softness of resorbable membranes. In this study, we tested the possibility to create and maintain a secluded space using a slow, long-lasting resorbable suture so that a resorbable dome device could support the barrier and immediately become a space-making device. Ten purely mucogingival recessions in ten patients were treated. At 12 months, the results were evaluated. In five subjects the gingival margin was within 1 mm of the cementoenamel junction, in four patients it was within 2 mm, and in one case a residual gingival recession was present (where the membrane became exposed). The mean root coverage obtained was 70.4%, while the mean gain of clinical attachment was 3.3 mm.

Absorbable Implants↗
PubMed2000

Tissue-specific expression of rat IL-18 gene and response to adrenocorticotropic hormone treatment.

IL-18 is a pleiotropic cytokine also proposed to have a role in modulating immune function during stress. Initially found in immune cells, IL-18 mRNA is detectable in several tissues including the cells of the zona reticularis and the zona fasciculata of the adrenal cortex, where its levels are elevated by acute stress or adrenocorticotropic hormone treatment. In the present study, we compared the expression of IL-18 in the adrenal cortex with that of spleen and duodenum, two other IL-18-positive tissues. In situ hybridization showed that, in contrast to the adrenal cortex, in spleen and duodenum IL-18 is primarily localized to immune cells. In duodenum, IL-18 mRNA was also detectable in epithelial cells. Northern blot demonstrated that while the adrenal gland synthesized IL-18 mRNA of 1.1 kb, spleen and duodenum produced a 0.9-kb transcript. RT-PCR, sequencing, Western blot, primer extension, and rapid amplification of cDNA end analysis demonstrated that the three tissues synthesize IL-18 mRNAs containing the same coding region and produce the same IL-18 peptide, but differ in the length of their 5'-untranslated region, indicating tissue-specific usage of the promoter region. Finally, in contrast to the adrenal gland, adrenocorticotropic hormone treatment did not increase the levels of IL-18 mRNA in spleen and duodenum. These results demonstrate tissue-specific expression and promoter usage of IL-18 gene and suggest that the adrenal cortex and not immune cells may be the source of IL-18 during stress.

Adrenal Glands↗
PubMed2000

Modulation of IL-18 production in the adrenal cortex following acute ACTH or chronic corticosterone treatment.

Interleukin (IL)-18 is a proinflammatory cytokine and a stimulator of cell-mediated immune responses. We have previously reported that acute stress stimulates the production of IL-18 mRNA in the glucocorticoid (GC)-producing cells of the adrenal cortex. In order to investigate the mechanisms governing the expression of IL-18 in the adrenal cortex, the effects of acute ACTH or chronic corticosterone treatment on the levels of IL-18 mRNA and protein were examined by in situ hybridization and Northern and Western blot assays. Adult male Sprague-Dawley rats received a subcutaneous injection of ACTH or subcutaneous implantation of slow-release corticosterone pellets followed by an injection of saline or ACTH. After 4 h, ACTH induced a 4-fold increase in IL-18 mRNA levels and elevated the content of pro-IL-18 peptide. Six days of chronic corticosterone treatment did not alter the basal levels of IL-18 mRNA and reduced those of pro-IL-18. Finally, ACTH treatment of animals under the corticosterone regimen induced a 2-fold increase in IL-18 mRNA and elevated the levels of the pro-IL-18 protein. The levels of the precursor, p45, and the active subunit p10 peptides of the IL-18-processing enzyme, IL-1beta-converting enzyme (ICE), showed no substantial differences in all the conditions tested. IL-1beta was not detected under these experimental conditions. These data demonstrate that the production of IL-18 in the adrenal cortex is stimulated by ACTH treatment and is not inhibited by the direct action of corticosterone. In contrast to the anti-inflammatory action of GCs, IL-18 may have an immunostimulatory role during acute stress.

Adrenal Cortex↗
PubMed1999

Unique regulation of immediate early gene and tyrosine hydroxylase expression in the odor-deprived mouse olfactory bulb.

Tyrosine hydroxylase (TH), expressed in a population of periglomerular neurons intrinsic to the olfactory bulb, displays dramatic down-regulation in response to odor deprivation. To begin to elucidate the importance of immediate early genes (IEG) in TH gene regulation, the present study examined expression of IEGs in the olfactory bulb in response to odor deprivation. In addition, the composition of TH AP-1 and CRE binding complexes was investigated in control and odor-deprived mice. Immunocytochemical studies showed that c-Fos, Fos-B, Jun-D, CRE-binding protein (CREB), and phosphorylated CREB (pCREB) are colocalized with TH in the dopaminergic periglomerular neurons. Unilateral naris closure resulted in down-regulation of c-Fos and Fos-B, but not Jun-D, CREB, or pCREB, in the glomerular layer of the ipsilateral olfactory bulb. Gel shift assays demonstrated a significant decrease (32%) in TH AP-1, but not CRE, binding activity in the odor-deprived bulb. Fos-B was found to be the exclusive member of the Fos family present in the TH AP-1 complex. CREB, CRE modulator protein (CREM), Fos-B, and Jun-D, but not c-Fos, all contributed to the CRE DNA-protein complex. These results indicated that Fos-B, acting through both AP-1 and CRE motifs, may be implicated in the regulation of TH expression in the olfactory bulb dopaminergic neurons.

Animals↗
PubMed1999

Histologic evaluation of guided vertical ridge augmentation around implants in humans.

Recent experimental and clinical case reports demonstrated vertical ridge regeneration in atrophic posterior mandibles and maxillae. Although the results from these clinical cases are quite encouraging there is a lack of human histologic data on the newly regenerated tissue around commercially available titanium implants. The aim of the present study was to perform a qualitative and quantitative histologic analysis of the bone response to previously exposed implant threads after treatment with guided bone regeneration in a series of patients. A total of 30 Nobel Biocare implants were consecutively placed in 6 patients with partially edentulous mandibles. Of these implants, 6 were planned for removal after 1 year, whereas the remaining 24 implants were inserted to function as support for a fixed partial denture. The 6 experimental implants were intentionally allowed to protrude occlusally 5 to 7 mm from the bone crest without counter-sinking. The exposed implant threads were completely covered by autogenous bone chips. After a 12-month healing period the 6 experimental implants were removed with trephine burs. Bone-to-metal contact and bone density in the implant threads were measured. Clinically, all implants were stable and there was complete tissue fill of the space underneath the membranes. Histologically, a substantial amount of new bone had formed underneath the membrane in all cases. Histomorphometrically, there was a lower bone-to-metal contact percentage in the exposed compared to the nonexposed region in every case. With respect to bone density, there was a mean of 43.2% in previously exposed regions compared to 60.3% in previously nonexposed regions.

Adult↗
PubMed1998

Histologic evaluation of new attachment utilizing a titanium-reinforced barrier membrane in a mucogingival recession defect. A case report.

Guided tissue regeneration was USED to treat a localized, deep, buccal recession on a mandibular left central incisor. This tooth was labially displaced and scheduled for extraction for orthodontic reasons. The mucogingival defect had 7 mm of facial gingival recession, and 4 mm mid-buccal probing depths. The attachment loss was 11 mm. There was no attached gingiva. At surgery the root was notched as landmarks for assessing the histological examination. A titanium reinforced barrier membrane was left in place for 4 weeks. At the time of extraction, 9 months post-initial treatment, there was a gain of 3 mm of root coverage and 1 mm of gingiva. The tooth and facial tissues were removed by block section for histologic evaluation. The root surface exhibited a total amount of a histologic new connective tissue attachment of 5.6 mm and regeneration of a new bone growth of 6.7 mm of bone. The histologic findings demonstrated that the coronal extent of the new attachment and new facial bone, 9 months after guided tissue regeneration treatment, were located coronal to the preoperative location, in a root surface previously exposed by a deep, long-standing recession.

Bone Regeneration↗
PubMed1998

Vertical ridge augmentation: surgical protocol and retrospective evaluation of 48 consecutively inserted implants.

The aim of this retrospective study was to evaluate the predictability of obtaining a vertical ridge augmentation around dental implants, strictly following a surgical protocol. Fourteen partially and four fully edentulous patients were treated between July 1993 and November 1995. Forty-eight consecutive implants were placed so that the circumference of the upper part of the cover screw was exposed from 2 to 7 mm. In addition to bone chips, autogenous bone grafts harvested with a bone-filtering aspirator were placed around the exposed threads and completely covered with a barrier membrane. Flaps were coronally displaced to cover the regenerative materials. Three of the 22 membranes became exposed prematurely and were removed immediately. The remaining 19 membranes stayed in place for a 12-month healing period until the second-stage surgery. In these 19 cases, where the membrane remained completely covered by the soft tissue, all of the available space underneath the membrane was filled with regenerative tissue. In eight cases a histologic biopsy was performed. Histologic analysis demonstrated vital bone with regularly formed bone cells; in three cases the most coronal part (approximately 1 mm) of the regenerative tissue was connective tissue, and the remaining tissue was bone. This retrospective analysis showed that when the clinical protocol was accurately followed, the possibility of clinical complication was reduced and the results for achieving vertical ridge augmentation around implants were predictable.

Adult↗
PubMed1997

Structure/function relationship of the cAMP response element in tyrosine hydroxylase gene transcription.

Expression of tyrosine hydroxylase (TH) is limited to catecholamine-producing neurons and neuroendocrine cells in a cell type-specific manner and is inducible by the cAMP-regulated signaling pathway. Previous results indicated that the cAMP response element (CRE) residing at -45 to -38 base pairs upstream of the transcription initiation site is essential for both basal and cAMP-inducible promoter activity of the 2.4-kilobase or shorter upstream sequence of the TH gene (Kim, K. S., Lee, M. K., Carroll, J. , and Joh, T. H. (1993) J. Biol. Chem. 268, 15689-15695; Lazaroff, M. , Patankar, S., Yoon, S. O., and Chikaraishi, D. M. (1995) J. Biol. Chem. 270, 21579-21589). Here, we further report that the CRE is critical for the promoter activity of the 5.6- or 9.0-kilobase upstream sequences of the rat TH gene, which had been shown to direct the cell-specific TH expression in vivo. To define the structure/function relationship of the CRE in transcriptional activation of the TH gene, we performed saturated mutational analyses of 12 nucleotides encompassing the CRE. Mutation of any nucleotide within the octamer motif results in a significant decrease of both basal and cAMP-inducible transcriptional activity of the TH reporter gene construct. Among the four nucleotides adjacent to the CRE (two 5' and two 3'), only the G residue at the immediate 3' position is important for full transcriptional activity. DNase I footprint analysis indicates a positive correlation between in vivo promoter activity and in vitro interaction between the CRE motif and its cognate protein factor(s). Reconstruction experiments using a TH promoter in which the native CRE was rendered inactive show that the CRE can transactivate transcription in either orientation through a window of approximately 200 base pairs upstream of the transcription initiation site, suggesting that CRE supports transcriptional activation of the TH gene in a distance-dependent manner. Finally, when the distance between the CRE and TATA box was changed by inserting an additional 5 or 10 bases, it was observed that both insertional mutations increased activity by approximately 3-fold. The cAMP inducibility was as intact as the wild type construct. Together, these results are consistent with a model in which transcriptional activation of the TH gene by the CRE requires that it be located within a certain proximity of the CAP site but does not depend on a stringent stereospecific alignment in relationship to the TATA element.

Animals↗
PubMed1997

Induction of interferon-gamma inducing factor in the adrenal cortex.

Interferon-gamma inducing factor (IGIF) is a recently identified cytokine also called interleukin-1gamma (IL-1gamma) or interleukin-18 (IL-18). Its biological activity is pleiotropic, and, so far, it has been shown to induce interferon-gamma production in Th1 cells, to augment the production of granulocyte-macrophage-CSF, and to decrease that of interleukin-10 (IL-10). We first detected newly synthesized IGIF mRNA by differential display in the adrenal gland of reserpine-treated rats and then isolated two transcripts by reverse transcription polymerase chain reaction. They were identified as rat IGIF on the basis of the high homology with mouse: 91% at both the nucleotide and the amino acid level. Subsequently, we investigated the effects of stress on IGIF mRNA levels and found that acute cold stress strongly induced IGIF gene expression. In situ hybridization analysis showed that IGIF is synthesized in the adrenal cortex, specifically in the zona reticularis and fasciculata that produce glucocorticoids. The presence of IGIF mRNA was also detected in the neurohypophysis although induction by stress was not significant. Our results call for more attention to the role of the adrenal gland as a potential effector of immunomodulation and suggest that IGIF itself might be a secreted neuroimmunomodulator and play an important role in orchestrating the immune system following a stressful experience.

Adrenal Cortex↗
PubMed1997

Spacemaking metal structures for nonresorbable membranes in guided bone regeneration around implants. Two case reports.

This article presents a surgical technique to promote bone regeneration and enlargement of localized alveolar ridge defects in the mandible. The purpose of this study was to investigate the use of spacemaking gold frames used in combination with expanded polytetrafluoroethylene Gore-Tex augmentation membranes (WL Gore) on two patients to create and maintain adequate space for the regeneration of bone. The membrane was sutured under the frame and the assembly was bent and adapted over the residual bony defect to create a dome and prevent the expanded polytetrafluoroethylene barrier membranes from collapsing into the defects. The framed membranes have also been positioned over dehisced implants. After a healing period of 12 months, a second-stage surgery procedure was performed to remove the gold frames and expanded polytetrafluoroethylene membranes and to connect the healing abutments. The gain of bone dimension was assessed by standardized measurements. On both patients the spaces created by the framed membranes were completely filled with newly regenerated bone. Biopsies from the treated sites revealed new bone formation.

Adult↗
PubMed1996

Inducible cAMP early repressor can modulate tyrosine hydroxylase gene expression after stimulation of cAMP synthesis.

Members of the CREB/CREM/ATF family of transcription factors either enhance or repress transcription after binding to the cAMP response elements (CREs) of numerous genes. The rat gene for tyrosine hydroxylase (TH) bears a canonical CRE, at base pairs -38 through -45 from the transcription initiation site, that is essential for basal and cAMP-stimulated transcription (Kim, K.-S., Lee, M. K., Carroll, J., and Joh, T. H. (1993) J. Biol. Chem. 268, 15689-15695; Lazaroff, M., Patankar, S., Yoon, S. O., and Chikaraishi, D. M. (1995) J. Biol. Chem. 270, 21579-21589). The current study identifies CRE-binding proteins induced in pharmacological paradigms characterized by TH activation. PC12- and rat adrenal gland-derived nuclear proteins retarded a TH-CRE oligonucleotide in gel mobility shift assays with virtually identical patterns. These differed substantially from patterns exhibited by extracts from locus ceruleus or from neuroblastoma (SK-N-BE()C) and locus ceruleus-derived (CATH.a) cell lines. Forskolin stimulation of PC12 cells and reserpine treatment of rats increased, in nuclear extracts derived from cells and adrenal glands, respectively, the amount of a fast moving CRE/protein complex that was supershifted by an anti-CREM antibody. Subsequent Western, Northern, and polymerase chain reaction analyses indicated that a specific member of the CREM family, the inducible cAMP early repressor (ICER), was strongly induced in both systems. Cotransfection of PC12 cells with TH2400CAT plasmid and the expression vector pCMV-ICER-Ib demonstrated that ICER efficiently represses the transcriptional activity of the TH gene promoter. In addition, PKA-stimulated transcriptional activity of the promoter was effectively suppressed by ICER. These results suggest that ICER can modulate cAMP-stimulated transcription of the TH gene and provide a model accounting for rapid reversal of increased TH transcription following elevations in cAMP.

Activating Transcription Factors↗
PubMed1996

The free rotated papilla autograft: a new bilaminar grafting procedure for the coverage of multiple shallow gingival recessions.

The aim of this clinical pilot study is to evaluate the possibility and from a statistical point of view, the predictability of a new mucogingival technique. The purpose of this surgical procedure is to cover the exposed buccal root surface with less than 5 mm clinical probing attachment loss either in corono-apical or mesio-distal aspects. This surgical procedure is particularly indicated in either single or multiple gingival recessions with perfectly preserved mesial and distal interproximal osseous crests, and with a papillary dimension not inferior to the defect which needs to be treated. A sharp incision is performed at a 90 degrees angle to the vestibule, following the mucogingival line. A sharp dissection is accomplished to create a partial thickness envelope flap on the underlying alveolar mucosa. The epithelium from the facial aspect of the papilla is debrided with a full thickness approach, the facial papillary tissue is removed from the underlying tissue bed. The papilla is then reversed in such a way that the base of the papilla is at the cemento-enamel junction (CEJ) and the apex is at the base of the gingival recession area. The papilla is then sutured in place and completely covered by a coronally displaced partial thickness flap. The results obtained either as root coverage, or as an aesthetic result, may be considered positive. This procedure has the decided advantage of a single surgical site, avoiding any palatal patient discomfort, good color compatibility with adjacent tissue, and healing by primary intention.

Adult↗
PubMed1996

Guided tissue regeneration versus mucogingival surgery in the treatment of human buccal recessions. A 4-year follow-up study.

The 4-year follow-up results of a clinical trial are reported. The clinical results of the treatment of buccal recession were analyzed comparing the outcomes of a guided tissue regeneration (GTR) procedure with nonresorbable membranes and a 2-step mucogingival procedure consisting of a coronally-positioned free gingival graft in two groups of 25 patients each. The final root coverage was 73.07% in the test group (GTR) and 72.3% in the control group (mucogingival surgery). In the test group, statistically significant recession reduction, probing depth reduction, clinical attachment level gain, and increase of keratinized tissue width were observed. In the control group the results were similar except for probing depth, which did not vary significantly. At the end of the 4-year follow-up period, the average periodontal conditions did not differ between the 2 groups, with the exception of the keratinized tissue width. This was obviously greater in the control group, where a free gingival graft had been carried out. Recessions > or = 5 mm had a greater root coverage after GTR treatment. In both groups, the periodontal parameters remained stable between 18 months and 4 years after surgery, indicating remarkable stability; the only exception was a significant increase in the keratinized tissue width in the test group. When the changes between the baseline and the 4-year follow-up were compared, the average reduction in the recession was similar in the two groups while probing depth reduction and clinical attachment level were greater in the GTR group.

Adolescent↗
PubMed1996

Vertical ridge augmentation: what is the limit?

The aim of this study is to show the possibility of achieving more than a 4-mm new vertical bone apposition on partially edentulous ridges. Six healthy, partially edentulous patients were treated from July 1993 to September 1993. After accurate radiographic investigation, all of the patients were treated using the Branemark System. After insertion, 14 fixtures were left circumferentially exposed for 37 mm. Autogenous bone graft harvested from a bone filter was placed around the exposed threads and completely covered with titanium-reinforced Gore-Tex augmentation membranes (TR-GTAM). Flaps were coronally displaced to passively cover the regenerative materials. Only one of the six membranes was exposed and it was removed immediately. After a 12-month healing period, the membranes were removed in conjunction with the second-stage surgical procedure. In the five cases where the membranes were kept covered, all of the available space underneath the TR-GTAM was filled with regenerative tissue. In all of the cases a histologic biopsy was performed. In one case all the space was filled with more than 7 mm of bone. In three cases all the space was filled with more than 5 mm of bone. In one case the most coronal part (approximately 1 mm) of the regenerative tissue was represented by connective tissue; the remaining tissue was represented by bone. The measurements demonstrated an average of vertical ridge augmentation of 4.95 mm. In the only case where the membrane underwent exposure and was then removed there was no regenerative tissue present.

Adult↗
PubMed1996

A clinical/statistical comparison between the subpedicle connective tissue graft method and the guided tissue regeneration technique in root coverage.

Subepithelial connective tissue grafts and guided tissue regeneration have been shown to be effective means to obtain root coverage. The purpose of this study is to compare statistically the results obtained with these techniques 1 year after the surgical procedures were performed. Thirty-six gingival recessions belonging to Class I and Class II of the Miller classification were treated: 18 cases with subepithelial connective tissue grafts (SCTG) and 18 cases with guided tissue regeneration (GTR). Each patient was randomly assigned to a group. At baseline, the group treated with subepithelial connective tissue grafts presented a mean recession of 4.88 mm, whereas the group treated with guided tissue regeneration presented a mean recession of 5.88 mm (P = .082). After 1 year, the mean root coverage was 77.08% in the SCTG group and 80.88% in the GTR group. The difference was not statistically significant (P > .05). The mean root coverage was 3.83 mm for the SCTG group and 4.61 mm for the GTR group. The mean gain in probing attachment level was 3.05 mm for the SCTG group and 5.55 mm for the GTR group. The difference was statistically significant (P = .01). In conclusion, the mean root coverage obtained was similar for the two groups, whereas the clinical attachment gain was greater in the GTR group. Therefore, it appears that the GTR technique is preferable when severe mucogingival defects are present and gain of clinical attachment level is mandatory.

Connective Tissue↗
PubMed1995

Coronally positioned palatal sliding flap.

A new flap design, the coronally positioned palatal sliding flap, was used to cover barrier membrane placed over implants in one patient, and to provide localized ridge augmentation around implants in another patient. The method is a valid surgical approach because of the favorable risk-benefit ratio. The surgical technique is easy to to perform, and it is possible to obtain a sufficient sliding position of the palatal tissue. This new palatal flap design may be indicated for a variety of periodontal surgical procedures, including guided tissue regeneration and implant surgery.

Alveolar Ridge Augmentation↗