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C Tinti

Publications and source records attributed to C Tinti.

32 records · Page 2Linked to original sources
PubMed1994

Antisense strategy unravels a dopamine receptor distinct from the D2 subtype, uncoupled with adenylyl cyclase, inhibiting prolactin release from rat pituitary cells.

The antisense strategy was used to unravel the functional contribution of the mRNAs encoding dopamine (DA) receptors to the multiple transduction mechanisms operated by DA in rat pituitary cells. An antisense oligonucleotide was designed to recognize seven nucleotides upstream and 11 nucleotides downstream from the initiation translation codon of the mRNA that encodes the DA D2 receptor. Addition of the antisense oligonucleotide for 7 days to primary culture of rat pituitary cells resulted in a decreased expression of DA D2 receptor as shown by (a) the virtual disappearance of [3H]spiroperidol binding sites and (b) the marked reduction in the levels of both the long and the short splice variant of the D2 receptor mRNAs. After this treatment, the DA D2 receptor agonist bromocriptine lost its capability both to inhibit adenylyl cyclase activity and to reduce prolactin mRNA levels. On the contrary, the inhibition of prolactin release induced by bromocriptine was affected minimally by the antisense oligonucleotide treatment. These data indicate that (a) translation of the mRNA encoding DA D2 receptors results in receptors that are negatively coupled with adenylyl cyclase and functionally linked to inhibition of prolactin synthesis; and (b) the release of prolactin might be regulated, at least in part, by a DA receptor that is encoded by mRNA species distinct from those encoding the D2 receptor.

Adenylyl Cyclase Inhibitors↗
PubMed1994

Cyclic AMP-dependent protein kinase regulates basal and cyclic AMP-stimulated but not phorbol ester-stimulated transcription of the tyrosine hydroxylase gene.

To define the precise role of cyclic AMP (cAMP)-dependent protein kinase (PKA) in transcriptional regulation of the tyrosine hydroxylase (TH) gene, we performed transient cotransfection analyses of a reporter construct containing the upstream 2,400 bp sequence of the rat TH gene with expression plasmids encoding a heat-stable specific inhibitor of PKA (PKI), a mutant regulatory subunit of PKA, or the catalytic subunit of PKA. Inhibition of PKA activity by expression of either PKI or mutant regulatory subunit blocked cAMP-stimulated induction and reduced basal transcription of the TH-reporter construct. Expression of the catalytic subunit of PKA induced the expression of the TH-reporter construct up to 50-fold in a dose-dependent manner. Primer extension analysis confirmed that PKA-mediated induction of TH-reporter expression occurred at the correct transcription initiation site. Expression of PKI did not affect induction following phorbol ester treatment, suggesting that PKA and protein kinase C (PKC) induce TH transcription by independent mechanisms. Finally, a double mutation within the cAMP response element (CRE) of TH2400-CAT diminished its basal and forskolin-stimulated transcription to the level of the promoterless plasmid, pBLCAT3, but did not alter the induction following treatment with phorbol ester, indicating that the CRE is not required for PKC-mediated transcriptional induction. Our results indicate that PKA, via the CRE, plays a crucial role for basal and cAMP-inducible transcription of the TH gene.

Base Sequence↗
PubMed1994

Expanded polytetrafluoroethylene titanium-reinforced membranes for regeneration of mucogingival recession defects. A 12-case report.

The regeneration of tissue to treat mucogingival recession defects is well established but these defects pose additional challenges for the clinician in the creation and maintenance of a space under the guiding membrane. We used titanium-reinforced membranes of expanded polytetrafluoroethylene (ePTFE) to facilitate the creation and maintenance of such spaces in 12 patients with mucogingival recession defects. The membranes were judged according to their ease of handling and placement and the regenerative results; the patients were evaluated for gingival recession and the quantity of attached gingiva before and for as long as 15 months after treatment. At 15 months, the average gingival recession was 1.4 mm (pretreatment = 5.3 mm), and the attached gingiva measured 3.3 mm (pretreatment = 1.4 mm). Titanium-reinforced ePTFE membranes result in a simpler, faster, and more predictable surgical procedure. Comparison of titanium-reinforced ePTFE membranes to other available procedures awaits assessment in clinical trials.

Adolescent↗
PubMed1994

The cAMP-dependent protein kinase regulates transcription of the dopamine beta-hydroxylase gene.

Dopamine beta-hydroxylase (DBH) catalyzes the conversion of dopamine to norepinephrine, and is expressed specifically in neurons and neuroendocrine cells that release norepinephrine and epinephrine. In the present study, we used DBH-expressing human neuroblastoma SK-N-BE(2)C and rat pheochromocytoma (PC12) cell lines to investigate the role of cAMP-dependent protein kinase (PKA) in transcriptional regulation of the DBH gene. Coexpression of the catalytic subunit of PKA (PKAc) robustly stimulated the transcriptional activity of the DBH gene in a dose-dependent manner. Conversely, coexpression of a specific inhibitor of PKA abrogated forskolin- and cAMP-mediated but not phorbol ester-mediated transcriptional induction of DBH. Deletion of the cAMP response element (CRE) dramatically reduced the stimulatory effect of PKA, indicating that the CRE mediates the induction of DBH by PKA. In DBH-nonexpressing HeLa and C6 glioma cell lines, coexpression of PKAc changed the transcriptional activity of the DBH promoter to a minimal degree, indicating that basal and PKA-mediated transcription of the DBH gene occur in a cell type-specific manner. Finally, both basal and cAMP-stimulated transcription of the DBH gene are diminished in three PKA-deficient PC12 cell lines, compared to wild-type cells. Based on these data, we conclude that PKA, via the CRE, plays an important role in basal and cAMP-inducible transcription, but is not required for phorbol ester-mediated induction, of the DBH gene in noradrenergic cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Deafferentation induces early and delayed differential changes in the pattern of expression of the various guanine nucleotide binding protein mRNAs in rat striatum.

A polymerase chain reaction-derived method was used to identify and quantitate the relative abundance of the different mRNAs encoding various isoforms of the guanine nucleotide regulatory protein Gs, Gi, and Go alpha subunits in the striata of rats unilaterally injected with 6-hydroxydopamine in the substantia nigra. Thirty days after the lesion, the mRNA levels of the G(o) and of the Gi 1 alpha subunits were increased by about 2-3 times, those of the Gi 3 decreased by about 60% and those of Gi 2 and Gs unmodified. The pattern of expression of the G(o) alpha subunits mRNA changed in a time-dependent fashion, being significant 20 days after the lesion. The decrease in Gi 3 alpha subunit mRNA levels was maximum 10 days after the lesion and tended to be reduced in magnitude with time while the changes in Gi 1 alpha subunit mRNA showed a byphasic behaviour being reduced at 10 days and increased at 30 days after the lesion. These data suggest that the expression of the various G protein alpha subunits in the striatum are continuously regulated by factors originating from afferent neurons and surrounding cells.

Animals↗
PubMed1993

Guided tissue regeneration in mucogingival surgery.

The use of expanded polytetrafluoroethylene (ePTFE) membranes in the treatment of mucogingival problems such as gingival recession, has been recently described. The major issues raised dealt with creating and maintaining space under the membrane and designing a flap that could be coronally positioned and at the same time capable of maintaining a good blood supply. The authors proposed the use of a trapezoidal flap and some technical space-making solutions, such as the use of a suturing technique and different metal structures to support the membranes.

Adult↗
PubMed1992

Rat pituitary cells selectively express mRNA encoding the short isoform of the y2 GABAA receptor subunit.

The GABAA receptor belongs to the ligand-gated ion channel receptor superfamily and appears to be composed of from 4 to 5 subunits which interact with each other. Molecular cloning of cDNAs encoding the different subunits of the GABAA receptor has revealed an unexpected heterogeneity which includes at least 4 homologous classes of subunits: these classes, designated as alpha, beta, gamma, and delta contain multiple variants. We have measured the steady-state levels of mRNAs encoding different (alpha 1, alpha 4, beta 1, beta 2, beta 3, gamma 2 long, gamma 2 short and delta) GABAA receptor subunits in the rat anterior pituitary and cerebellum using a polymerase chain reaction (PCR)-derived method. We found that pituitary cells express mRNAs encoding the alpha 1, beta 1 and beta 3 GABAA receptor subunits whereas the transcripts for alpha 4, beta 2 and delta were undetectable. We also found that pituitary cells selectively express the short isoform of the gamma 2 subunit mRNA. These data indicate that the expression of the various GABAA receptor subunits is cell-specific and support the concept that the diversity in function and pharmacology of the GABAA receptor is based on the ability of cells to specify the expression of selective GABAA receptor subunits.

Animals↗
PubMed1992

Guided tissue regeneration versus mucogingival surgery in the treatment of human buccal gingival recession.

A surgical technique involving membranes was used to treat localized human buccal recessions 3 mm to 8 mm. The results on 25 patients (test group) were evaluated 18 months postoperatively and compared with the results obtained in 25 other patients (control group) having undergone mucogingival surgery. In the test group, a trapezoidal flap with a large base was raised beyond the mucogingival junction. The exposed root surface was scaled thoroughly to a concave shape. A membrane was bent and adapted onto the concave root surface. The flap was sutured far coronally and the membrane removed one month later. The control patients underwent a 2-step procedure, consisting of a free gingival graft and a coronally positioned flap. The amount of root coverage obtained was similar in the 2 groups (test = 72.73%; control = 70.87%), although the clinical attachment gain (test = 5.12 mm; control = 3.56 mm) and pocket variation (test = 1 mm reduction; control = 0.06 mm increase) differed significantly (P < 0.001). The keratinized tissue width was greater in the control group. The regression analysis showed that the amount of covered root surface after treatment was in strict correlation with the depth of the original recession in the test group, while no correlation was found in the control group. The expected root coverage was greater in the test group when the recession was greater than 4.98 mm, while it was greater in the control group when the recession was less than 4.98 mm. These results indicate that a guided tissue regeneration procedure can be used to successfully treat recession. The membrane procedure compared favorably with the mucogingival surgery in the treatment of deep recession.

Adolescent↗
PubMed1992

Guided tissue regeneration in the treatment of human facial recession. A 12-case report.

A guided tissue regeneration procedure was used to treat human buccal recessions, 3 to 7 mm deep, in 12 patients. No procedure for increasing the width of keratinized tissue was performed prior to treatment. A thick bipedicled flap was raised with a semilunar incision in the alveolar mucosa and a marginal incision was extended to the adjacent papilla. The root surface was made concave by curets and burs to create space for regeneration. The membrane was fixed to the cemento-enamel junction and covered by the flap which consisted of the residual gingiva and of alveolar mucosa. The membranes were removed 4 weeks after placement. The patients were recalled 6 months after the reentry procedure. The average reduction in recession was 2.50 mm (P less than 0.01) and the average attachment gain was 2.84 (P less than 0.01). Pocket depth was slightly reduced (0.33 mm), although the degree of reduction was not of statistical significance. The width of keratinized tissue increased slightly (0.83 mm). These results demonstrate the possibility of treating human buccal recessions by means of a guided tissue regeneration procedure, with predictable recession reduction and attachment gain. A minimal amount of keratinized tissue was needed.

Adult↗
PubMed1992

Periodontal regenerative therapy with coverage of previously restored root surfaces: case reports.

Two case reports are presented to demonstrate a treatment that restores proper esthetics, cures hypersensitivity, and enhances periodontal support for cases of root caries or failing Class V restorations associated with gingival recessions. The procedure involves removing the existing restoration, elevating a trapezium-shaped full thickness flap, root planing to achieve a desired concave shape, and placing a barrier membrane. In both cases, satisfying clinical results have been maintained for 18 months.

Adult↗
PubMedDate not supplied

Dopamine D2, D3, and D4 receptor mRNA levels in rat brain and pituitary during aging.

Reverse Transcriptase-Polymerase Chain Reaction technique was used to determine the levels of the mRNAs encoding different receptors belonging to the D2 family in various brain areas of 6-, 12-, 18-, and 24-month-old rats. We found a progressive, age-dependent reduction in the mRNA levels of D2 short and D2 long receptors in corpus striatum, substantia nigra, and frontal cortex. D2 short and D2 long receptor mRNA levels were unchanged in hippocampus and olfactory tubercle, while they increased in pituitary. D3 receptor mRNA levels were reduced in olfactory tubercle and unchanged in striatum. D4 receptor mRNA levels were unmodified in pituitary gland. These data suggest that the molecular mechanisms responsible for regulating the pattern of expression of the various dopamine receptors are differentially regulated by aging.

Aging↗
PubMedDate not supplied

Treatment of peri-implant defects with the vertical ridge augmentation procedure: a patient report.

Most clinical patient reports apply the biologic principles of guided bone regeneration, in addition to defect filling with autogenous bone grafts or bone graft substitutes, in peri-implantitis therapy. Not infrequently, sites with membrane coverage have revealed early exposure, with subsequent infections, premature membrane removal, and insufficient bone regeneration. The present patient report demonstrates another surgical approach that uses the clinical principles and soft tissue management of vertical ridge augmentation, strictly following the same surgical protocol, on previously cleaned implant surfaces. The successful outcome of this surgical approach in one patient supports the feasibility of the selected treatment method in maintaining both the implants and the prosthetic reconstruction involved with peri-implantitis.

Alveolar Ridge Augmentation↗