[Radionuclide venography. A new method of studying the venous system].
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Adolescent↗
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Evaluation of a simpler technique for in-vivo labelling of red blood cells with 99mTc.
The efficiency of labelling red blood cells with intravenously administered 99mTcO4, by prior oral administration of stannous chloride dihydrate, has been evaluated. Optimum labelling occurred 1 hr after the oral dose of 200 mg of SnCl2.2 H2O and 20 min after the intravenous injection of 99mTcO4. The mechanism of labelling has been shown to be diffusion of 99Tc through the cell membrane followed by binding to haemoglobin in the presence of reducing agent. The in-vivo labelling technique has been found to be useful for the diagnosis of an abdominal mass and for static perfusion studies.
Administration, Oral↗
A closed eye contact lens model of corneal inflammation. Part 2: Inhibition of cytochrome P450 arachidonic acid metabolism alleviates inflammatory sequelae.
PURPOSE: The authors have previously shown a marked increase in corneal epithelial arachidonic acid metabolism to 12-hydroxyeicosatetraenoic acid (12-HETE) and 12-hydroxyeicosatrienoic acid (12-HETrE) in a model of closed eye-contact lens wear. Their formation was predominantly cytochrome P450-dependent and significantly correlated with inflammatory score and corneal thickness. In the current study, the authors used stannous chloride to inhibit the epithelial cytochrome P450-dependent synthesis of 12-HETE and 12-HETrE to assess the role of these eicosanoids as mediators of the inflammatory response to contact lens wear in the closed eye. METHODS: Hydrogel contact lenses were soaked in stannous chloride (100 micrograms/ml) or vehicle and fitted to the rabbit eye in stacked fashion (two lenses/eye), followed by a silk suture tarsorrhaphy of approximately 90%. Eyes were analyzed over a 7-day period for inflammatory responses through slit lamp biomicroscopy, subjective inflammatory scoring, ultrasonic pachymetry, and corneal epithelial [1-14C]-arachidonic acid metabolism. RESULTS: Closed eye-hydrogel contact lens wear resulted in a progressive anterior surface inflammatory response. Coinciding with these events was a time-dependent increase in corneal thickness and 12-HETE and 12-HETrE production rates by corneal epithelial homogenates. Treatment of the lenses with stannous chloride (100 micrograms/ml) significantly attenuated by day 7 the inflammatory score (56% decrease), corneal thickness (17% decrease), and 12-HETE and 12-HETrE synthesis (77% and 71% decrease, respectively). CONCLUSIONS: This study further substantiates the involvement of cytochrome P450, through the synthesis of 12-HETE and 12-HETrE, in the inflammatory response associated with hydrogel contact lens wear in the closed eye. Thus, inhibition of cytochrome P450, with subsequent decreases in 12-HETE and 12-HETrE, may attenuate the pathophysiologic response to contact lens wear in the closed eye.
12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
Near-UV light protection effect against lethality induced by stannous chloride in Escherichia coli.
Stannous chloride (SnCl2) is a reducing agent largely employed in industry and in medical procedures. To evaluate its potential genotoxicity, several Escherichia coli strains were treated with SnCl2 and their survival rates determined. Results showed that the double mutant on specific genes for the repair of deoxyribonucleic acid damage was the most sensitive strain. Simultaneous near-UV illumination inhibited the lethal effect of SnCl2 in the wild type strain. Although the nature of the induced lesions are not known these results indicate the potential genotoxicity of SnCl2.
DNA Repair↗
Facilitation of transmitter release from mouse motor nerve terminals by stannous chloride.
Although a mixture composed of 30 microM stannous chloride (SnCl2) and 75 microM tartaric acid (TA) facilitates neuromuscular transmission in the frog, the mixture had no effect on the endplate potential (e.p.p.) in the rat. The present study has been undertaken to determine whether the responses of the mouse (mammalian) to SnCl2 are different from those of the frog (amphibian). The mixture had no effect on the resting potential or the membrane resistance of the muscle fiber. The mixture did not change the e.p.p. amplitude, but TA (75 microM) significantly decreased it. The mixture increased the quantal content of the e.p.p., but TA decreased it. The mixture raised the frequency of the miniature endplate potential (m.e.p.p.) in the high potassium-medium. In normal saline, both the mixture and TA decreased both the m.e.p.p. frequency and its amplitude. These results suggest that SnCl2 itself facilitates the transmitter release from nerve terminals in the mammalian as well as in the amphibian species.
Animals↗
A study on cellular reactions and fibrogenic effects of mineral dusts.
In vivo cytotoxicity including cellular metabolic activity, lysozyme content and total protein content in rat bronchoalveolar lavage, capacity of interleukin-1 released from rat pulmonary cells and fibrogenic effects evaluated from rat lung dry weight, collagen content of the whole lung and pathological grading induced by mineral dust were assayed. The results showed that: (1) The relationship among in vivo cytotoxicity, interleukin-1 release, fibrogenic effects on the lung induced by mineral dusts correlated well with the free SiO2 content in mineral dusts in most (but not all) cases; (2) The biological harmful effects of mixed dusts were not simply the additive effect of single dust. In the group of WO3-SiO2 mixture, the fibrogenicity was mainly due to SiO2, tungsten trioxide (WO3) showed neither fibrogenic effect, nor significant potentiality to enhance SiO2 fibrogenicity, while in the group of SnO2-SiO2, SnO2 was suppressive to the effect of SiO2, although the contents of SiO2 in the two mixed dusts were similar.
Animals↗
Tin tetrachloride interaction with human hemoglobin.
In the presence of tin tetrachloride, the rate constant for the rebinding of CO to the triliganded hemoglobin, l'4, is much increased and the number of molecules participating in the CO ligation is decreasing. The pH drops, but a proton consumption process also takes place at the same time. The heme and its environment do not seem to change much, but the tin complexing to protein is very probable. The oxidation of hemoglobin in the form of either oxy or carbonmonoxy occurs with rather high rate.
Carbon Monoxide↗
Augmentation of calcium influx by stannous chloride at mouse motor nerve terminals.
Stannous chloride (SnCl2) facilitates the calcium (Ca) entry into the frog motor nerve terminals. To compare the mode of action of SnCl2 on the Ca channels in the mouse with that in the frog, we investigated the effects of SnCl2 on the inward Ca current at the nerve terminals. SnCl2 (0.1 mM) did not change the second positive component of the action potential (an outward potassium (K) current) at the terminal part of the nerve terminal. SnCl2 (0.1 mM) increased the amplitude of the prolonged negative or positive deflection (an inward Ca current) evoked by treatment with 1 mM tetraethylammonium and 0.1 mM 3,4-diaminopyridine at the terminal or preterminal part of the nerve terminal, respectively. This augmenting effect of SnCl2 was inhibited by cumulative addition of Ca channel blockers, i.e., 0.1 mM CdCl2, 5 mM NiCl2, 5 mM CoCl2, 5 mM MnCl2, or 10 mM MgCl2. From the results obtained, it has been confirmed that SnCl2 facilitates the transmitter release by enhancing the Ca influx at the nerve terminals but not by blocking the K channels and that the mode of action of SnCl2 in the mouse is identical with that in the frog.
Action Potentials↗
The effect of finishing and polishing on surface roughness of a processed resilient denture liner.
A raised ridge on a Molloplast-B sample was removed using one of three burs, four stones, or a coarse sandpaper disc. Samples were polished using pumice alone, tin oxide alone, or both agents. A flat, unfinished sample served as a control. The average surface roughness was measured after reductions and subsequent polishings. The length of time required for initial reduction was recorded. Average surface roughness measurements ranged from 16.0 to 1.4 microns, with the control measuring 0.66 micron. Without polishing, burs produced rougher surfaces than stones and required longer times for reduction. Bur samples also remained rougher than stone samples after pumicing. No significant differences were found between treatments or controls after the use of either a combination of pumice and tin oxide or tin oxide alone.
Acrylic Resins↗
Ecotoxicology of organotin compounds.
Organotin compounds are ubiquitous contaminants in the environment. The high biological activity of some compounds toward aquatic organisms lead to deleterious impacts in aquatic ecosystems. Here, the aquatic ecotoxicology of organotins is reviewed based on a multidisciplinary approach involving environmental chemical, toxicological, and ecological aspects. Basic results were obtained both with field and laboratory studies, and some of the most important recent results and conclusions are critically reviewed. The contamination of and fate in aquatic systems is reported and linked with effects at different levels of biological organization. Major emphasis is placed on the development of a concept of ecotoxicology that encompasses not only effect assessment alone, but also integrates environmental chemistry with aquatic toxicology. Thereby, the influence of speciation for bioavailability, basic modes of toxic action, and aquatic toxicity are discussed. This case study on organotins allows to a certain extent generalizations to ecotoxicology in general.
Animals↗
p-Nitrobenzyl side-chain protection for solid-phase synthesis.
A solid-phase supported peptide synthesis (SPPS) strategy using p-nitrobenzyl (pNB) esters, thioethers and carbamates for side-chain protection is described. The synthesis of Fmoc p-nitrobenzyl side-chain protected amino acids of lysine, cysteine, glutamic acid and aspartic acid are synthesized and incorporated into the synthesis of tetramers by standard Fmoc methodology using Wang polystyrene resins. Deprotection is carried out on resin in mildly acidic reducing conditions, using a solution of DMF, SnCl2, phenol and HOAc. The yellow by-products associated with the deprotection of the pNB protecting group are then removed by treatment with a solution of benzene sulfinic acid in DMF. The methodology is successfully extended in the synthesis of a peptide with multiple pNB protecting groups.
Acetates↗
Synergistic relationship between luting and priming agents and gold restorations plated with stannic oxide.
Bonding to dentin and enamel has increased restorative treatment options, provided the materials are used to optimum advantage. Restorative dentists must understand the indications and the proper mechanisms for using these materials. As with many techniques and procedures, it takes more time to describe than to accomplish. The tooth-conditioning and cementing steps are standard treatment procedures used daily in most dental offices. Tin-plating and preparing the metal surface are laboratory procedures and consume no chair time. The clinical advantages of bonding--such as resistance to microleakage and recurring decay, enhanced retention, preservation of tooth structure, and extended restoration prognosis--far outweigh the modest increase in placement time.
Cementation↗
Osseointegration of rough acid-etched implants: one-year follow-up of placement of 100 minimatic implants.
Between January 1992 and October 1992, 100 Minimatic screw implants made of titanium alloy with rough acid-etched surfaces were placed in 63 consecutive partially edentulous patients. At second-stage (uncovering) surgery performed after a 4- to 6-month healing period, none of the implants showed any signs of mobility, peri-implant infection, or bone loss. After an additional healing phase averaging 2 weeks, the patients were restored with fixed prostheses. Patients were reexamined every 3 months for 1 year, with all 63 patients available for evaluation during this period. Periapical radiographs were taken preoperatively, immediately after surgery, and at 6 and 12 months after implantation. There were no signs of peri-implant radiolucencies in any of the implants, and alveolar bone loss was less than 1 mm on average 1 year after implantation. Based on Plaque Index, sulcular bleeding index, pocket probing depth, attachment level, width of keratinized mucosa, and hand-tested mobility, 99 implants were considered successful and 1 (which developed peri-implant infection) was considered a failure. Study results substantiate other reports that implants with a rough surface can yield predictable good results.
Alloys↗
In vitro corrosion behavior and microstructure examination of a gallium-based restorative.
Concerns of mercury toxicity have led to the development of gallium-based restorative materials to replace dental amalgam. A new gallium-based dental restorative, Galloy, was compared with a high-copper amalgam, Permite, for anodic polarization behavior in deoxygenated Ringer's solution and by immersion testing in normal Ringer's solution at 37 degrees C. Corrosion products were analyzed using energy dispersive X-ray spectrometry and transmission electron diffraction. The data from both sources were consistent with the presence of alpha-Ga2O3 and SnO2 as the primary corrosion products of Galloy. Anodic polarization behavior of Galloy- and Permite-coupled specimens suggests that coupling Galloy with the more noble Permite amalgam may cause accelerated electrochemical corrosion and that Galloy is more corrosion prone than Permite.
Corrosion↗
Evaluation of technetium-99m decay on Escherichia coli inactivation: effects of physical or chemical agents.
Technetium-99m (99mTc) has been used in nuclear medicine and in biomedical research to label molecular and cellular structures employed as radiotracers. Here, we have evaluated, on a DNA repair proficient Escherichia coli strain, the 99mTc decay inactivation and the influence of the (i) pre-treatment with metal ion chelators or of the (ii) treatment with a free radical scavenger on the protection of the cells against the lethal effect of the 99mTc. As SnCl2 is frequently used as a reducing agent in the 99mTc-labeling process, we have also studied the capability of SnCl2 to alter the biological effects induced by the 99mTc decay. As we are exposed to either chemical or physical agents in the nature, we have decided to study a possible influence of the ultraviolet solar radiation in the biological phenomena induced by the 99mTc decay. Our data point out (i) a very important role of the Auger and/or conversion electrons in the cytotoxicity induced by the 99mTc decay; (ii) SnCl2, the metal ion chelators and the free radical scavenger protect the cells against the lethal effect of the 99mTc; and (iii) near-UV does not alter the lethal effect of the 99mTc decay.
2,2'-Dipyridyl↗
[Closing of the filling cleft with copper and mercury compounds in fillings of silver-tin amalgams].
After measuring the tearing pressure of bubbles, the remaining marginal fissures (unavoidable with silver-tin amalgams) were completely eliminated by cauterizing cavities with an activated copper suspension. The effect is based on the activated copper forming voluminous basic Cu compounds. This procedure gives the silver-tin amalgam the bactericidal characteristics of a copper amalgam but essentially higher marginal strength. As expected, the teeth were not discolored. Measurement of mercury vapor showed a distinct decrease in the release of mercury vapor in the direction of the cavity.
Copper↗
Insoluble zinc, cupric and tin pyrophosphates inhibit the formation of volatile sulphur compounds.
Oral malodour is mainly a result of the production of volatile sulphur compounds (VSC). The present study was concerned with investigating the anti-VSC effect of insoluble pyrophosphates (PP) of zinc, copper(II) and tin(II). The hypothesis to be tested was that the sulphide anions produced when VSC are solubilized in water have a higher affinity for the respective metal ions than the PP anion. The anti-VSC effects of insoluble PP were compared with the corresponding soluble metal salts using three in vitro methods: saliva putrefaction; dialysis of a suspension of PP and saliva against water; and analysis of water containing hydrogen sulphide and methyl mercaptan gases, and gases in the headspace. The levels of VSC were analysed by gas chromatography in the first and third methods, and released metal ions were analysed by atomic absorption spectroscopy in the second. The results showed that: the insoluble metal PP inhibited VSC formation in saliva by 99-100%; under dialysis, only minute amounts of metal ions are released from the combination of PP and saliva; and the PP lost their metal cations in water containing dissolved gases and inhibited VSC formation. Hence, the results support the experimental hypothesis. Sulphide ions are obviously very strong ligands for these metal ions.
Adult↗
Inhibition of cell proliferation and antitumor activity of a novel organotin compound.
Organotin compounds showed more antineoplastic effect against P388 leukemia in mice than any other class of compounds. However, they have not received as much attention as the platinum compounds. The present compound, Et2SnCl2.L [L = N-(2-pyridylmethylene)-4-toluidine] (OTC), showed an Sn-N bond length of 2.46 A which, because it is bigger than 2.39 A, is expected to achieve better formation of tin-DNA complexes. We previously reported on the synthesis and biological activity of this compound and on its ability to cause a delay in cell proliferation and sister chromatid exchanges in mouse bone marrow cells. In this study, we carried out further investigations on the antiproliferative and antitumor activity of OTC in relation to the cellular glutathione (GSH) level, which plays an important role in the cellular defense mechanism. OTC induced significant delay in the cell cycle in mouse bone marrow cells and, when the GSH level was low, the extent of the delay was reduced. The antitumor activity was determined in accordance with the US National Cancer Institute (NCI) standard protocol for primary screening in Dalton's lymphoma (DL) that was maintained by serial intraperitoneal transplantation. The T/C (treated/control) value was 146% when organotin was treated after transplantation; this improved significantly when buthionine sulfoximine (BSO), a GSH-depleting agent, was added 24 hours before the tin treatment. Our data suggest that the present tin compound has antiproliferative ability and can increase the survival of mice bearing DL. The endogenous GSH level influences the effect of the tin compound.
Animals↗