SEARCH · Search PubMed

Results for “SEALS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 739 records · Page 41Linked to original sources

PubMed2004

A new tissue-sealing technique using the Ligasure system for nonanatomical pulmonary resection: preliminary results of sutureless and stapleless thoracoscopic surgery.

PURPOSE: We present our initial evaluation of a new surgical technique of lung tissue sealing for nonanatomical pulmonary resection composed of sutureless and stapleless thoracoscopic surgery. DESCRIPTION: Twelve patients who required therapeutic thoracoscopic pulmonary resection from April 2001 to April 2002 were recruited for this study. Resection of lung parenchyma was performed with an ultrasound-driven scalpel, and the cut end was sealed using LigaSure, a new bipolar system. Measurement of the cut surface after resection during the surgery and assessment of LigaSure sealing strength was performed. EVALUATION: There were no deaths or major intraoperative complications. The mean operation time was 65 minutes, and mean hemorrhage volume was 46 mL. Average chest drain duration was 3 days, and average hospital stay was 6 days. One patient with a giant bulla and cut surface diameter of 50 mm experienced persistent air leak for 1 week. Late complications did not occur over the 8-month follow-up period. CONCLUSIONS: Video-assisted thoracoscopic surgery pulmonary resection using LigaSure instead of staplers appears technically feasible and easy, and produces satisfactory preliminary results. Although further studies are required to confirm the sealing strength and reliability of LigaSure, this technique should be considered for use in nonanatomical pulmonary resections.

Aged↗

PubMed1999

Gelatin-resorcinol-formaldehyde-glutaraldehyde glue for sealing pulmonary air leaks during thoracoscopic operation.

BACKGROUND: Intraoperative pulmonary air leakage is one of the most troublesome complications in video-assisted thoracoscopic surgical procedures. We developed a sealing procedure using gelatin-resorcinol-formaldehyde-glutaraldehyde (GRFG) glue for pulmonary air leaks during such operations. METHODS: Formaldehyde-glutaraldehyde (FG) jelly is prepared by mixing FG fluid with 2.5% sodium carboxymethyl cellulose to make the FG fluid viscous. We performed an adhesion-strength test to determine the optimum ratio of gelatin-resorcinol mixture to FG jelly and then conducted an air leakage test on swine lung to compare the sealing effect between fibrin and GRFG glues. To study the histotoxicity of the GRFG glue, the sealant was applied to injured rabbit lung, and the rabbits were followed for 1 day to 188 days. For clinical studies, we developed an endosyringe to apply the GRFG glue on the target site during video-assisted thoracoscopic surgical procedures and used this technique in 21 patients with intraoperative air leaks. In addition, the side effects of GRFG glue application were studied in 52 patients in whom glue was used in several ways during lung operations. RESULTS: The results of the adhesion-strength test favored a 2:1 gelatin-resorcinol to FG ratio. The mean pressure required to produce air leakage was significantly higher with GRFG glue than with fibrin glue (p<0.001). No critical histologic damage was seen in the rabbit lung, and the glue persisted on the lung surface for 188 days after sealing. Clinical application of the glue in 21 patients resulted in complete stoppage of air leakage during operation and long afterward, except in 1 patient with a late-onset lung fistula. The FG jelly helped prevent glue spillage at the target site, regardless of angle. A transient rise in temperature up to 38.60C was observed as a side effect 7 days after operation in 5 (9.6%) of the 52 patients. CONCLUSIONS: A GRFG glue using FG jelly seals pulmonary air leaks effectively, simply, and safely during video-assisted thoracoscopic surgical procedures.

Animals↗

PubMed2000

Barrier permeability at cut axonal ends progressively decreases until an ionic seal is formed.

After axonal severance, a barrier forms at the cut ends to rapidly restrict bulk inflow and outflow. In severed crayfish axons we used the exclusion of hydrophilic, fluorescent dye molecules of different sizes (0.6-70 kDa) and the temporal decline of ionic injury current to levels in intact axons to determine the time course (0-120 min posttransection) of barrier formation and the posttransection time at which an axolemmal ionic seal had formed, as confirmed by the recovery of resting and action potentials. Confocal images showed that the posttransection time of dye exclusion was inversely related to dye molecular size. A barrier to the smallest dye molecule formed more rapidly (<60 min) than did the barrier to ionic entry (>60 min). These data show that axolemmal sealing lacks abrupt, large changes in barrier permeability that would be expected if a seal were to form suddenly, as previously assumed. Rather, these data suggest that a barrier forms gradually and slowly by restricting the movement of molecules of progressively smaller size amid injury-induced vesicles that accumulate, interact, and form junctional complexes with each other and the axolemma at the cut end. This process eventually culminates in an axolemmal ionic seal, and is not complete until ionic injury current returns to baseline levels measured in an undamaged axon.

Animals↗

PubMed2002

Nonequilibrium cryopreservation of rabbit embryos using a modified (sealed) open pulled straw procedure.

The study was designed to evaluate the efficiency of a modified (sealed) open pulled straw (mOPS) method for cryopreserving rabbit embryos by vitrification or rapid freezing. An additional objective was to determine whether the mOPS method could cause the vitrification of a cryoprotectant solution generally used in rapid freezing procedures. Two consecutive experiments of in vitro and in vivo viability were performed. In Experiment 1, the in vitro viability of rabbit embryos at the morula, compacted morula, early blastocyst and blastocyst stages was assessed after exposure to a mixture of 25% glycerol and 25% ethylene glycol (25GLY:25EG: vitrification solution) or 4.5 M (approximately 25% EG) ethylene glycol and 0.25 M sucrose (25EG:SUC: rapid freezing solution). Embryos were loaded into standard straws or mOPS and plunged directly into liquid nitrogen. The mOPS consisted of standard straws that were heat-pulled, leaving a wide opening for the cotton plug and a narrow one for loading embryos by capillarity. The embryos were aspirated into the mOPS in a column positioned between two columns of cryoprotectant solution separated by air bubbles. The mOPS were then sealed with polyvinyl-alcohol (PVA) sealing powder. The vitrification 25GLY:25EG solution became vitrified both in standard straws and mOPS, whereas the rapid freezing 25EG:SUC solution crystallized in standard straws, but vitrified in mOPS. The total number of embryos cryopreserved was 1695. Embryos cryopreserved after exposure to each solution in mOPS showed higher rates (88.2%) of survival immediately after thawing and removal of the cryoprotectant than those cryopreserved in 0.25 ml standard straws (78.8%; P < 0.0001). After culture, the developmental stage of the cryopreserved embryos significantly affected the rates of development to the expanded blastocyst stage. Regardless of the cryoprotectant used, lower rates of in vitro development were obtained when the embryos were cryopreserved at the morula stage, and higher rates achieved using embryos at blastocyst stages. Based on the results of Experiment 1, the second experiment was performed on blastocysts using the mOPS method. Experiment 2 was designed to evaluate the in vivo viability of cryopreserved rabbit blastocysts loaded into mOPS after exposure to 25GLY:25EG or 25EG:SUC. Embryos cryopreserved in mOPS and 25GLY:25EG solution gave rise to rates of live offspring (51.7%) not significantly different to those achieved using fresh embryos (58.5%). In conclusion, the modified (sealed) OPS method allows vitrification of the cryoprotectant solution at a lower concentration of cryoprotectants than that generally used in vitrification procedures. Rabbit blastocysts cryopreserved using a 25GLY:25EG solution in mOPS showed a similar rate of in vivo development after thawing to that shown by fresh embryos.

Animals↗

PubMed1991

Long-term sealing ability of a calcium hydroxide sealer.

A calcium hydroxide sealer (Sealapex) was compared with a zinc oxide and eugenol sealer (Tubli-Seal) over a 32-wk interval to examine solubility in an in vitro simulation. After obturation with gutta-percha and the appropriate sealer, specimens were immediately immersed in a saline solution to challenge the sealers' solubility. The solutions were changed weekly to allow for a continued dissolution of the sealers and to prevent establishment of an equilibrium between the solution and the sealers. The 2- and 32-wk specimens were removed from the solutions, immersed in India ink for 3 days, and then made transparent by a clearing process. Microscopic examination was used to determine the linear penetration of the ink for each tooth. Results revealed that Sealapex statistically had no greater dissolution (based upon linear penetration) than Tubli-Seal at both 2 and 32 wk. It is suggested that Sealapex has a sealing ability comparable to Tubli-Seal and can withstand long-term exposure to tissue fluids without significant leakage. This may allow time for the biochemical action of the calcium hydroxide to stimulate physiological calcification of the apical foramen.

Calcium Hydroxide↗

PubMed1990

In vitro evaluation of the sealing ability of a calcium phosphate cement when used as a root canal sealer-filler.

A calcium phosphate cement (CPC) was examined for its ability to seal the root canal when used as a sealer-filler. Extracted human teeth were divided into three groups. Root canals were filled with either CPC paste containing dicalcium phosphate anhydrous (group 1), CPC containing dicalcium phosphate dihydrate (group 2), or gutta-percha points sealed with Grossman's cement (group 3). After filling, all specimens were kept in 100% humidity for 1 day, immersed in a CaPO4 solution or distilled water at 37 degrees C for 1 wk, and then immersed in 1% Poly-R dye solution at 37 degrees C for 1 wk, after which they were rinsed and sectioned longitudinally for microscopic examination. Specimens in groups 1 and 2, especially those aged in the CaPO4 solution showed considerably less dye penetration than those in group 3. The good sealing ability of the CPC against dye penetration in vitro suggests that it may provide an adequate seal of the canal without a separate sealer.

Calcium Phosphates↗

PubMed1998

Ultrasonic root-end preparation: influence of cutting angle on the apical seal.

Apical resection is fundamental in obtaining a correct apical seal. The purpose of this study was to evaluate how the apical root resection angle and the cavity made by ultrasonic retrotips may influence the apical seal. A total of 48 extracted teeth were endodontically treated and sealed by guttapercha vertical compaction: 24 were resected with a 45 degrees angle and 24 with a 90 degrees one. An ultrasound source (P.M. 400 EMS) and a CT5 Scaler were used to make the retrograde cavity that was filled afterwards with EBA-zinc oxide-eugenol alumina-added cement. Apical leakage was determined using fuchsin and assessed after the roots were sectioned longitudinally. Linear dye penetration in dentin and at the interface between dentin and cement was measured with a stereomicroscope (x 12 magnification), and the results were statistically analyzed. Results showed that there was less infiltration both in dentin and in the space between the filling and the dentinal wall in the group with the 90 degrees angle, but this difference was statistically significant (p < 0.0001) only for the dentin. None of the samples showed leakage greater than the depth of the preparation. An apical cavity of 3 mm or more along the vertical axis can produce a safe and effective seal.

Bicuspid↗

PubMed2001

Sealing and dentin bond strength of adhesive systems in selected areas of perfused teeth.

OBJECTIVES: (1) Test the sealing capacity and tensile strength of various adhesive systems: Scotch Bond 1 (Single Bond in USA)(SB1)+Z100, Syntac Sprint (SYN)+Tetric Ceram, Prime and Bond 2.1 (PB21)+TPH Spectrum, F2000 (Adhesive+Compomer) (F2000) and Optibond Solo (OPT)+Prodigy, to perfused teeth (30 cm distilled H2O), in select areas. (2) Determine the relationship between sealing ability and size of adhesive area (BA) with tensile strength (TS). METHODS: Segments of human third molars (n=67) sealed with amalgam on their coronal side were connected to a perfusion system (30 cm distilled H2O), to measure the basal permeability. Access cavities were drilled through the amalgam to expose dentin (area range: 8.7-20.8 mm2) and measure the permeability of that area. Cavities were sealed with one of the test materials and permeability measured prior to tensile testing. The percentage of decrease in permeability (PPD) that occurred with the different combinations of materials was also measured. RESULTS. TENSILE STRENGTH: there were no statistically significant differences among groups. PERMEABILITY: ANOVA showed that there were statistically significant differences in the mean % decrease in permeability (PPD) among groups (p=0.018). Student-Newman-Keuls test (p<0.05) detected that the mean PPD of F2000 ranked statistically higher than that of SB1. Relationship among variables: a linear correlation was found defined by the formula TS=7.47+0.008 x PPD-0.23 x BA, with a significance of the model p=0.0097. SIGNIFICANCE: None of the materials studied reduced permeability up to 100%. They all produced low tensile bond strengths (maximum mean value of groups: 5.51 MPa (OPT)).

Acetone↗

PubMed1998

Silicone oil tamponade to seal macular holes without position restrictions.

OBJECTIVE: The authors performed a study to determine the effectiveness and safety of silicone oil as a substitute for gas to fill the vitreous cavity to treat macular holes. DESIGN: Multicenter, nonrandomized, interventional trial. PARTICIPANTS: Thirty-seven consecutive patients chose vitrectomy with silicone tamponade instead of gas to treat 40 eyes with stage-2 to stage-4 idiopathic age-related macular holes. Stage-2 holes constituted 40% of the holes, and stage-3 and stage-4 holes made up 60%. INTERVENTION: All eyes were treated with vitrectomy, manual detachment of the posterior vitreous face (not done for stage-4 holes), autologous serum instillation, and silicone fill of the vitreous cavity. After insertion of the oil, the patients resumed normal activity with no restriction of head or eye position except to avoid faceup position. The oil was removed after approximately 6 weeks. MAIN OUTCOME MEASURES: The authors considered the seal of the macular hole and the preoperative and postoperative logarithm of the minimum angle of resolution (logMAR) visions the most significant measures for comparison to other studies. RESULTS: Eighty percent of all holes and 86% of holes not treated previously were sealed with a single silicone tamponade of the vitreous cavity. The logMAR value of visual acuity improved an average of 0.26 (2.6 lines) to 0.61 (20/81) for all eyes and 0.34 (3.4 lines) to 0.52 (20/66) when the macular hole sealed. Completeness of fill of the vitreous cavity with silicone affected seal of the macular hole. Three of eight eyes in which open holes developed after oil removal had less than 90% fill of the vitreous cavity by silicone. Sixty-nine percent of lenses increased opacity one grade or were removed after silicone tamponade. There were no significant adverse effects arising from silicone tamponade. CONCLUSIONS: Silicone oil tamponade of macular holes is effective and safe. Silicone may be optimal for the treatment of macular holes in persons who must travel, who cannot maintain facedown positioning, or who have monocular vision. The most important factor in the successful closure of the macular hole was the completeness of fill of the vitreous cavity with silicone oil.

Adult↗

PubMed1996

Trace element accumulation in Baikal seal (Phoca sibirica) from the Lake Baikal.

Trace element concentrations (Fe, Mn, Zn, Cu, Pb, Ni, Cd, Co and Hg) were determined in 60 Baikal seals and in fishes collected from Lake Baikal in 1992. Low levels of Hg and Cd were found in Baikal seals in comparison with those of marine mammals and it was due to their low concentrations in dietary fish. These results suggest that pollution by Hg and Cd was low in Lake Baikal and these toxic elements were unlikely to be the causative factors for mass mortality of Baikal seal in 1987-1988. Significant correlation of Hg concentration between hair and internal tissues suggested the use of hair for Hg monitoring in pinnipeds. Among essential elements, higher Fe and lower Cu levels were specifically found in the liver of Baikal seal. The noticeable accumulation of essential elements might be related to the unique and specific environment of Lake Baikal.

Journal Article↗

PubMed1997

Geographical variation of persistent organochlorine concentrations in blubber of ringed seal (Phoca hispida) from the Canadian Arctic: univariate and multivariate approaches.

Geographical variation of organochlorine (OC) concentrations in ringed seal (Phoca hispida) in the Canadian Arctic was studied using univariate and multivariate statistical techniques. The dataset consisted of 80 individual OC components (58 PCB congeners plus DDT- and chlordane (CHL)-related compounds, toxaphene, hexachlorocyclohexanes (HCH), chlorobenzenes (CBz), and dieldrin) determined in 221 ringed seal blubber samples from 13 locations throughout the Canadian Arctic from the period 1983 to 1989. Mean concentrations of the major OC groups in ringed seal blubber (SigmaPCBs, SigmaDDT, SigmaCHL and toxaphene), adjusted for the age and sex of the seals, showed few significant geographical differences. Principal components analysis was used to examine geographical trends. Significant differences in mean factor scores for three of four principal components were found between sampling locations. Locations in the western and high Arctic could be distinguished from those in Hudson Bay by highest scores along principal component two which was associated principally with CBz. PCB congeners with six or more chlorine substitutions declined with increasing north latitude, whereas more volatile OCs (CBz, HCH, less chlorinated PCBs) increased in the proportion of total OCs with latitude. Proportions of less chlorinated PCBs also decreased with increasing longitude, whereas slopes of regressions for more highly chlorinated PCBs increased significantly. The results were generally consistent with the 'cold condensation' hypothesis of increasing proportions of more volatile OCs with increasing latitude and distance from sources.

Journal Article↗

PubMed2001

[Early deambulation following cardiac catheterization by the use of 6 Fr Angio-Seal, a new hemostatic percutaneous puncture closure device].

INTRODUCTION AND OBJECTIVES: Efficacy of the hemostatic puncture closure 8 Fr Angio-Seal device for percutaneous puncture closure after a catheterism has been previously demonstrated, but the experience provided has been obtained with 8 Fr devices. At present the device has been modified and its size reduced to 6 Fr. In this pilot study we evaluate the efficacy of the new hemostatic 6 Fr Angio-Seal device and its safety when early deambulation post-diagnostic and/or therapeutic catheterization is established. PATIENTS AND METHODS: Prospective study of 150 consecutive patients randomized either for application of the 6 Fr Angio-Seal device (group A; n = 75), in which early ambulation was indicated, or manual compression (group B; n = 75), with ambulation 12 h after cardiac catheterization. Basal data, including clinical and angiographic characteristics and previous treatment with heparin and platelet aggregation inhibitors were similar in both groups. RESULTS: The time of hemostasia was significantly shorter in group A than in group B (118 +/- 210 s in A vs 1320 +/- 370 s in B; p (3/4) 0,001), and with early ambulation (3,1 +/- 0,4 h in A vs 12,3 +/- 3,1 h in B; p (3/4) 0,001) no local complications were observed. CONCLUSIONS: The 6 Fr Angio-Seal hemostatic device diminished the hemostasia time and early ambulation could be achieved. In this pilot study no complications due to early movilization were observed, but the safety of the new hemostatic device after diagnostic or therapeutic catheterizations needs to be evaluated in greater series.

Absorbable Implants↗

PubMed2002

Gamma-ray computed tomography to characterize soil surface sealing.

The application of sewage sludge as a fertilizer on soils may cause compacted surface layers (surface sealing), which can promote changes on soil physical properties. The objective of this work was to study the use of gamma-ray computed tomography, as a diagnostic tool for the evaluation of this sealing process through the measurement of soil bulk density distribution of the soil surface layer of samples subjected to sewage sludge application. Tomographic images were taken with a first generation tomograph with a resolution of 1 mm. The image analysis opened the possibility to obtain soil bulk density profiles and average soil bulk densities of the surface layer and to detect the presence of soil surface sealing. The sealing crust thickness was estimated to be in the range of 2-4 mm.

Journal Article↗

PubMed2005

The lantibiotic lacticin 3147 produced in a milk-based medium improves the efficacy of a bismuth-based teat seal in cattle deliberately infected with Staphylococcus aureus.

A preparation of the bacteriocin lacticin 3147 (prepared from a demineralized whey protein fermentation liquor) was combined as a powder with a bismuth-based intramammary teat seal and evaluated for its potential as an antimicrobial in non-lactating cows. The lacticin/teat seal formulation enabled significant bacteriocin release from the seal without the requirement for a surfactant. Studies in vivo in lactating cows demonstrated that this formulation was effective in reducing bacterial recoveries (approximately 20-fold) from teats deliberately inoculated with Staphylococcus aureus after infusion. Moreover, this formulation also significantly reduced the numbers of Staph. aureus recovered from teats that were exposed to the challenge bacterium before the infusion of the teat seal preparation. The powdered preparation of lacticin 3147 did, however, cause some teat irritation as evidenced by associated rises in somatic cell count (SCC). However, this effect was short-lived and when the mean SCC readings pre-infusion and the final two readings post-infusion were compared, there was no significant difference in the immunological acceptance between treatments.

Animals↗

PubMed2004

Stability of Corynosoma populations with fluctuating population densities of the seal definitive host.

In theory there should be a strong coupling between host and parasite population sizes. Here, we investigated population size and structure in 3 species of acanthocephalans, Corynosoma semerne, C. strumosum and C. magdaleni, in ringed seals (Phoca hispida) from the Bothnian Bay over a period of more than 20 years. During this period, seal numbers first decreased markedly and then increased steadily; at the same time, a paratenic fish host particularly important for C. strumosum has gradually disappeared from the bay due to decreasing salinity. We found no evidence that the mean abundance of any of the 3 acanthocephalan species changed significantly over time, nor was there any relationship between parasite abundance at any point in time and seal numbers in the corresponding year. Based on the proportion of sexually mature female worms per infrapopulation, and on relationships between the sex ratio of worms and infrapopulation size, both C. magdaleni and C. semerme appear to be doing well, independently of the population size of their seal definitive hosts. In contrast, perhaps because of the loss of its main paratenic host, C. strumosum appears more at risk in the Bothnian Bay. Our results show that in complex natural systems, there are not necessarily simple, direct links between definitive host population size or density, and parasite population dynamics.

Acanthocephala↗

PubMed2001

A comparison of retention and the effect on caries of fissure sealing with a glass-ionomer and a resin-based sealant.

OBJECTIVE: To compare the retention and the caries preventive effect of a glass-ionomer developed for fissure sealing (Fuji III) and a chemically polymerized resin-based fissure sealant (Delton). DESIGN: A split mouth randomized design using contralateral teeth. SETTING: WHO Regional Demonstration, Training and Research Center for Oral Health, Damascus, Syrian Arab Republic. SAMPLE AND METHODS: 179 children, 7 years old at the start of the study, were recruited from schools close to the Center. Only children with at least one pair of permanent first molars that were caries free or only had incipient lesions were included in the study. Follow-up examinations for sealant retention were done after 6 months, 1 year, 2 years and 3 years. The number of children available for reexamination was 129 (after 6 months); 121 (after 1 year); 115 (after 2 years) and 116 (after 3 years). Four dental hygienists were trained in the sealant procedures and did approximately one fourth of the sealants each. RESULTS: After 3 years the glass-ionomer sealant was completely lost in almost 90% of the teeth compared to less than 10% of the resin sealed teeth. After 3 years the relative risk of a tooth sealed with glass-ionomer over that of a tooth sealed with resin was 3.38 (95% CL: 1.98; 5.79). This finding was consistent over type of tooth. CONCLUSIONS: The glass-ionomer sealant tested in the present study had poorer retention and less caries protective effect than the resin-based sealant used.

Bisphenol A-Glycidyl Methacrylate↗

PubMed1978

Inhibition by calcium ions of adenosine cyclic monophosphate formation in sealed pigeon erythrocyte 'ghosts'. A study using the photoprotein obelin.

1. Sealed pigeon erythrocyte 'ghosts' were prepared containing ATP and the Ca2+-activated photoprotein obelin to investigate the relationship cyclic AMP formation and internal free Ca2+. 2. The 'ghosts' were characterized by (a) morphology (optical and electron microscopy), (b) composition (haemoglobin, K+, Na+, Mg2+, ATP, obelin), (c) permeability to Ca2+, assessed by obelin luminescence and (d) hormone sensitivity (the effect of beta-adrenergic agonists and antagonists on cyclic AMP formation). 3. The effect of osmolarity at haemolysis and ATP at resealing on these parameters was investigated. 4. Sealed 'ghosts', containing approx. 2% of original haemoglobin, 150mM-K+, 0.5MM-ATP, 10(3)--10(4) obelin luminescence counts/10(6) 'ghosts', which were relatively impermeable to Ca2+ and in which cyclic AMP formation was stimulated by beta-adrenergic agonists over a concentration range similar to that for intact cells, could be prepared after haemolysis in 6mM-NaCl3mM-MgCl2/50mM-Tes, pH7, and resealing for 30min at 37 degrees C in the presence of ATP and 150mM-KCl. 5. The initial rate of adrenaline-stimulated cyclic AMP formation in these 'ghosts' was 30--50% of that in intact cells and was inhibited by the addition of extracellular Ca2+. Addition of Ca2+ to the 'ghosts' resulted in a stimulation of obelin luminescence, indicating an increase in internal free Ca2+ under these conditions. 6. The ionophore A23187 increased the rate of obelin luminescence in the 'ghosts' and also inhibited the adrenaline-stimulated increase in cyclic AMP. 7. The effect of ionophore A23187 on obelin luminescence and on cyclic AMP formation in the 'ghosts' was markedly decreased by sealing EGTA inside the 'ghosts'. 8. It was concluded that cyclic AMP formation inside sealed pigeon erythrocyte 'ghosts' could be inhibited by more than 50% by free Ca2+ concentrations in the range 1--10 micrometer.

Adenosine Triphosphate↗

PubMed1998

Comparison of marginal sealing ability of new generation bonding systems.

The purpose of this in vitro study was to evaluate the enamel and dentine marginal sealing ability of four new generation composite bonding systems. Two Class V preparations, which were solely in enamel and dentine/cementum, were made on the buccal surfaces of 96 freshly extracted molar teeth. The teeth were randomly divided into four groups of 24 and restored with composite resin (Silux Plus) utilizing the following bonding systems: Scotchbond Multi-purpose (SB), Fuji Bond LC (FB), Prime & Bond 2.0 (PB) and Bisco One-step (BC). The restorations were finished immediately after photo-polymerization and stored in saline at 37 degrees C for 1 week. Half of the specimens in each group were then thermally stressed for 500 cycles. All restorations were then subjected to dye penetration testing, sectioned and scored. Results revealed no statistically significant difference (P < 0.05) in dye penetration scores for the different bonding systems with the exception of leakage at the dentine margins of thermally stressed specimens where FB exhibited significantly better sealing ability compared with the other bonding systems and BC exhibited significantly less leakage than PB. The marginal seal of 'one-step' (PB and BC) and resin-modified glass-ionomer (FB) bonding systems appear to be as effective as 'two step' systems like SB. Thermal stresses had some influence on marginal seal but this was both product and tissue specific.

Bisphenol A-Glycidyl Methacrylate↗