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TiN: a suitable coating for defibrillator electrodes?

The electrochemical behavior of porous TiN coating for defibrillator electrodes was investigated by in vitro studies. A commercially available Ti patch was compared with a Ti patch coated with a layer of porous TiN. Similarly, the influence of the TiN coating on a Pt/Ir intracardial electrode was tested. Porous TiN coatings were made by reactive sputtering on the plain electrodes. Electrode potential measurements were performed during monophasic anodic and cathodic defibrillator shocks delivering energies between 1 J and 49 J. Porous TiN coating of Pt/Ir coils was found suitable to deliver cathodal pulses, while a plain coil remains recommended for anodic shocks. TiN coating was of benefit for conventional Ti patches. Particularly, in the case of anodic shocks, the TiN layer protected the Ti-mesh from immediate oxidation. However, above 70 anodic shocks of 49 J, the TiN coating underwent oxidation to an oxynitride. An estimated 180 anodic shocks of 10 J could be delivered before TiN oxidation became measurable by increased polarization.

Biocompatible Materials↗

Anti-nutritive effects of dietary tin.

Tin is usually present in foods at levels of less than 4 micrograms/g. Higher levels may be found in some processed foods due to the addition of tin-based preservatives and stabilizers or to corrosion and leaching of the metal from unlacquered cans or from tin foils used in packaging. Estimates of dietary intake range from about 0.2 to greater than 5 mg Sn/day. Diets including a high proportion of canned vegetables and fish could supply greater than 30 mg Sn/day. Although intakes from dietary sources are generally considered to be harmless, a variety of adverse effects of tin have been reported, including effects on serum and bone alkaline phosphatase, lactic dehydrogenase, heme oxygenase, and 5-aminolevulinic acid dehydratase. Perturbations in glutathione metabolism have been reported, as have adverse effects on metabolism of essential trace minerals such as copper, zinc, and iron. Specific effects on calcium content of bone, serum, and kidney have also been described. Reported effects vary with the chemical form, dose of tin, and route and frequency of administration. Effects of tin in animal systems and on essential trace mineral absorption and excretion in human volunteers are reviewed. A summary of recent investigations on dietary tin-copper interactions and effects of tin on rat hepatocellular antioxidant protection are also presented.

Animals↗

Optical and chemical methods of metal ash analysis and tin recovery.

'Metal ash' presents a waste disposal problem in most of the developing countries as the industries employ obsolete technologies. In this paper we describe analysis of tin ash, zinc ash and aluminium ash by means of optical methods, such as X-ray diffraction (XRD), inductively coupled plasma mass spectrometry (ICP-MS), electron probe micro analysis (EPMA), scanning electron microscopy (SEM) and chemical methods. The results of tin ash obtained by XRD method matched well with the cassiterite, a naturally occurring mineral of tin. ICP-MS studies reveal the presence of a large number of tracer metals, which may cause pollution by tertiary dispersion and this aspect is discussed. Conversely, the data generated by chemical methods are limited. However, the methods are simple and cost-effective. Then, they can easily be adopted by low-budget industries. Simple and cost-effective process to recover tin from tin ash is described. It is based on heating tin ash with sodium cyanide to about 900 degrees C to separate tin component from the metal ash. The process recovers good quality tin and offers a very high yield. The process can be scaled up to small pilot plant.

Environmental Monitoring↗

The in vitro effects of zinc and manganese on delta-aminolevulinic acid dehydratase activity inhibited by lead or tin.

The effects of the administration of lead and tin on delta-aminolevulinic acid dehydratase (5-aminolevulinate hydro-lyase, ALAD, EC 4.2.1.24) activity in human, rabbit, and mouse blood were studied in vivo. In addition the ability of zinc, manganese, and dithiothreitol (DTT) to restore ALAD activity in the blood of lead- or tin-treated subjects was examined in vitro. Manganese, zinc, and DTT restored ALAD activity in vitro. The optimal concentration of zinc required in vitro was 10(-4) M in blood of lead-exposed humans and lead- or tin-administered mice, and 10(-3) M in blood of rabbits treated with either lead or tin. Even at the optimal concentration of zinc, the reactivating effect was incomplete, the highest recovery being about one-third of the control activity. However, the simultaneous addition of zinc and DTT increased ALAD activity to levels comparable with those of controls. Manganese was less effective than zinc in restoring ALAD activity in vitro; the effective dose was 10(-2) M in the blood of lead-exposed subjects, while little effect was noted in tin-treated subjects. Manganese was as effective as DTT in protecting against the inhibition of ALAD activity in vitro by excessive zinc. In contrast, DTT restored ALAD activity completely in the blood of tin-treated rabbits and produced about an 80% recovery of enzyme activity in the blood of tin-treated mice, but only a 35% recovery in the blood of lead-treated rabbits. These results suggest that the mechanisms by which lead and tin inhibit ALAD activity are different.

Animals↗

Tin distribution in adult and neonatal rat brain following exposure to triethyltin.

The uptake, distribution, and elimination of tin were determined in adult and neonatal (Postnatal Day 5) rat brain following ip administration of triethyltin bromide (TET). Groups of five adult CD rats were killed at 10 min, 1 hr, 4 hr, 24 hr, 5 days, or 10 days following acute exposure to 6.0 mg/kg TET; an additional group of adult animals was killed at 24 hr following exposure to either 3.0, 6.0, or 9.0 mg/kg (N = 5/dosage). The time course for tin distribution in 5-day-old rat pups was determined by killing pups 10 min, 30 min, 1 hr, 4 hr, 8 hr, 12 hr, 24 hr, 5 days, 10 days, or 22 days following exposure to either 3.0 or 6.0 mg/kg TET (N = 4/dosage/time). Tin analyses were performed by flameless atomic absorption spectrophotometry. The t1/2 for total tin in the adult rat brain following 6.0 mg/kg TET was determined to be 8.0 days. The maximum concentration in the adult was reached at 24 hr and corresponded to 4.6, 9.6, and 16.6 ng tin/mg protein for dosages of 3.0, 6.0, and 9.0 mg/kg, respectively. Tin was evenly distributed across all brain areas studied. For animals exposed to 6.0 mg/kg TET on Postnatal Day 5, the t1/2 for total tin in the brain was 7.3 days. A maximum concentration of 9.9 ng tin/mg protein was reached at 8 hr postexposure. The rate of elimination of tin from the brain (as measured by the elimination rate constant kel) did not differ significantly between adults and neonates. However, due to a dilution effect by the rapid brain growth of the neonate, the concentration of tin in the neonatal brain following TET administration decreased significantly faster than that in the adult.

Animals↗

Tin--a toxic heavy metal? A review of the literature.

A tolerable limit for tin concentration in canned food of 250 ppm (Fritsch et al., 1977) is generally accepted. However, biochemical effects attributable to tin have been observed even after oral administration of 1 and 3 mg Sn/kg body wt (Yamaguchi et al., 1980). These doses reflect 10 and 30 ppm tin in the diet. The experiments of de Groot (1973) showed that hemoglobin concentrations in the blood of rats decreased significantly feeding a diet containing 150 ppm tin. The absorption of iron was diminished after simultaneous administration of 0.8 mumol Sn(II) and iron, reflecting a tin dose of 95 ppm tin, by injection into jejunal loops of rats (Schäfer and Forth, 1983). In general, however, canned food usually plays a secondary role in daily nutrition. Fortunately, concentrations of about 2000 ppm tin as reported by Warburton et al. (1962) and Barker and Runte (1972) are not found in canned food, but values between 50 and 500 ppm are not unusual (Piscator, 1979). If a large amount of canned food is eaten daily over a long period, disturbances of gastric acid secretion and a reduction in iron absorption or heme metabolism cannot be excluded. The storage of food, especially acid foods, in opened cans should be avoided as this practice increases the amount of tin in the food when it is consumed.

Animals↗

Cardiac damage secondary to occupational exposure to tin vapor.

Tin is commonly used as a coating on copper kitchen appliances, and "tinsmithing" as a trade is common in many non-Western countries, where cooking utensils are re-tinned when the cooking surface wears thin. Tinsmiths, or "tinkers," are commonly exposed to the following fumes during their work: stannic [tin(IV)] oxide, ammonium chloride, and hydrochloric acid. In this study we assessed workers from tinsmith workshops of our province for signs, symptoms, and laboratory evidence of cardiac end-organ damage. Between June 2002 and March 2003, researchers went to the main tinsmith workshop area of our province to interview tinsmiths in their workplaces and to gather addresses of their "traveling tinker" colleagues, who work with portable equipment. All workers were interviewed and underwent a complete physical examination, blood testing for lipid parameters, and echocardiography. Twenty-six tin workers (mean age 49+/- 10 y) and 25 control patients (convenience sample of hospital employees) were included in the study. Tobacco use, incidence of hypertension, and serum lipid parameters were not significantly different between the two groups (p < .05). The differences in myocardial performance index, systolic function, and mitral flow A velocity were also nonsignificant. However, the mitral inflow E velocity in the tinsmiths was significantly less than in controls (0.71+/- 0.1 vs. 0.95+/- 0.1 m/s, p < .001). The mitral deceleration time was also much longer in the tinsmith group (216+/- 71 ms vs. 143+/- 14 ms, p < .001). Eleven of the tinkers (23%) were found to have aortic valve sclerosis (severe in one, moderate in another, mild in the other nine), but aortic valve sclerosis was found in none of the control subjects. One tinsmith was found to have three-vessel coronary disease on angiogram. Another tinker with "myocarditis" in the past, and slow flow on angiography, had normalization of his cardiac tests after refraining from tin exposure for 6 mo. Thus, occupational exposure to heavy tin fumes is associated with left ventricle diastolic dysfunction and sclerosis of the aortic valve. Tin workers should minimize their exposure to tin fumes, and physicians should monitor tinsmiths closely for signs of heart disease.

Adult↗

Accumulation of calcium in kidney and decrease of calcium in serum of rats treated with tin chloride.

Effect of tin on the kidney calcium and serum calcium concentration was studied in rats intraperitoneally administered with tin chloride. The calcium concentration in kidney was significantly increased by administration of tin (1.0 mg/100 g), and this increase was dose dependent. A significant increase in the level of kidney calcium was not exhibited by the administration of zinc, manganese, or lead. The increased calcium after the administration of tin predominantly accumulated in the cortex of kidney. The administration of tin did not show a significant alteration of sodium and potassium concentration in the kidney. The level of serum calcium was significantly decreased by the administration of tin (2.0 mg/100 g), and this reduction was dose dependent. The decrease of serum calcium by the administration of tin was associated with the accumulation of calcium in the kidney by treatment with tin.

Animals↗

Evaluation of employee exposure to organic tin compounds used as stabilizers at PVC processing facilities.

Organic tin compounds are primary substances used as heat stabilizers by the polyvinyl chloride (PVC) industry. The use of these compounds in the PVC industry is generally well controlled, usually by automated processes. This study was conducted to provide an overview of worker exposure to organic tin compounds at PVC processing facilities and to verify that these exposures are below the threshold limit value (TLV((R))) set by the American Conference of Governmental Industrial Hygienists for organic tin. The basis of the TLV indicates the principal concern is to minimize adverse effects on immune function and the central nervous system from airborne exposure to organic tin. The TLV has a skin designation based on the potential for percutaneous absorption; the TLVs for inhalation exposures are based on the presumption that there is no concurrent exposure via the skin and oral ingestion routes. Personal exposure monitoring was conducted following the National Institute for Occupational Safety and Health (NIOSH) 5504 sampling method and a modified version of the NIOSH analytical method. The results were reported as"total tin."The data indicated no average exposure levels for individual tasks exceeded the organic tin TLV, and 96%of results the samples were less than 20%of the TLV. Only 1 sample of 102 exceeded the TLV, and the individual was wearing appropriate respiratory protection. Subsequent investigation indicated the highest exposures occurred while the operators were conducting tasks that included manual handling of the organic tin compounds. These data suggest manual operations may have a greater potential for organic tin exposure.

Environmental Monitoring↗

The anticorrosion ability of titanium nitride (TiN) plating on an orthodontic metal bracket and its biocompatibility.

Typically, an orthodontic metal bracket is made from stainless steel. It has been shown that such metal may corrode in an acid- and chloride-rich environment. The purpose of the current study was to investigate a titanium nitride (TiN) ion-plated stainless steel orthodontic bracket's anticorrosion properties and compare its biocompatibility with that of non-TiN-plated brackets. The stainless-steel brackets studied here were tested in acidic artificial saliva. The plated metal bracket was produced by the titanium nitride (TiN) ion-plating method. The TiN-plating on the bracket surface was demonstrated to be successful by EDX analysis. The quantity of metallic-ion release under test immersion solutions was analyzed by atomic absorption spectrophotometry. Both TiN- and non-TiN-plated brackets may release detectable ions into the test solution, including nickel, chromium, manganese, copper, and iron (ferric). The anticorrosion ability of the plated bracket was analyzed by means of inductively coupled plasma atomic emission spectroscopy. The results revealed that the TiN-plated metal bracket did not increase the anticorrosion ability of the standard bracket. The biocompatibility of the TiN plating versus the standard bracket material resulting from bracket immersion in the test solution revealed no toxicity on U2OS cells using a methylthiazole tetrazolium (MTT) colorimetric assay. Clearly, the search for an improved technique for enhancing the anticorrosion ability of the normal metal orthodontic bracket should be continued.

Cell Line↗

DA-7911, 188Rhenium-tin colloid, as a new therapeutic agent of rheumatoid arthritis.

Radiation synovectomy is one of the most useful methods for treating patients with refractory synovitis because of its convenience, long-term effects, repeatability and the avoidance of surgery. In this study, we investigated the toxicity, stability and biodistribution of a rhenium-188 (188Re)-tin colloid to evaluate its suitability as a synovectomy agent. Twenty four hours after injecting the 188Re-tin colloids (74 KBq/0.1 mL) into the tail vein of ICR mice, most of the 188Retin colloidal particles was found in the lungs. In addition, there were no particle size changes at either room temperature or at 37 degrees C after injecting the 188Re-tin colloids in human plasma and synovial fluid. In vitro stability tests showed that the 188Re-tin colloid remained in a colloidal form without a critical size variation over a 2-day period. We investigated the leakage of 188Retin colloids from the intraarticular injection site with gamma counting in New Zealand white rabbits. The 188Re-tin colloids (55.5 MBq/0.15 mL) were injected at the cavum articular and the mean retention percentage of the 188Re-tin colloid was 98.7% for 1 day at the injection site, which suggests that there was neither change in the particle size nor leakage at the injection sites. In the biodistribution study with the SD rats, the liver showed the highest radioactivity (0.0427% ID/organ) except for the injected knees (99.49%). In the SD rats, mild toxicities including the skin or a synovium inflammation were observed as a result of a radioactivity of 15 mCi/kg at the intraarticular injection site. However, there was no systemic toxicity. In the Ovalbumin (OVA)-induced arthritic rabbits, the 188Re-tin colloid improved the macroscopic, the histological score and reduced the knee joint diameter when compared to the arthritic control. In conclusion, a 188Re-tin-colloid is considered as a strong candidate for radiation synovectomy with a superior efficacy and safety.

Animals↗

Dispersion of TiN in aqueous media.

The dispersion of TiN powders in aqueous media was studied through XPS, zeta potential, adsorption, sedimentation, and rheology measurements. XPS showed that there are TiO2, TiN, and TiOxNy sites on the TiN particle surface. In the absence of dispersant, the isoelectric point (pH(IEP)) of the TiN particles was at pH 2.2. Based on the surface properties of TiN particles, a cationic polymer, polyethylene imine (PEI), was selected as a dispersant. In the presence of PEI, the pH(IEP) shifted from pH 2.2 to pH 11.10. It was evidenced that TiN slurries could be stabilized around pH 9.50 with 1-2 wt% PEI as dispersant. Subsequently, TiN slurries with solid content as high as 57 vol% were developed and exhibited dilatant rheological behavior at high shear rate. The results showed that PEI is an effective dispersant for TiN in aqueous media.

Journal Article↗

Solid-state NMR studies of some tin(II) compounds.

High-resolution NMR spectra of [Formula: see text] nuclei, particularly (119)Sn and (31)P, in solid tin(II) phosphite, SnHPO(3), and tin(II) phosphate, SnHPO(4), are presented. The results are discussed in relation to the crystal structures. Spinning sideband analysis has been carried out for both nuclei, giving information on the shielding tensors. Satellite peaks allow the indirect Sn,Sn coupling constants to be determined. Surprisingly large values of 2600+/-200Hz and 4150+/-200Hz are reported for SnHPO(3) and SnHPO(4) respectively. The satellite peaks were investigated by using a single Hahn echo for each refocusing time, which showed that the observed splittings result from (119)Sn, (117)Sn coupling. For SnHPO(3), the calculated relative intensities of the satellites for six intra-layer coupling interactions are in agreement with the experiment values, but for SnHPO(4) the coupling appears to be inter-layer in nature. Tin-119 (and in one case phosphorus-31) shielding tensor data derived from MAS NMR are also reported for four other crystalline tin(II) compounds, namely tin diphosphate, tin oxalate, tin sulphate and calcium tin ethylenediamine tetraacetate.

Journal Article↗

False-negative biopsies for the diagnosis of testicular intraepithelial neoplasia (TIN)--an update.

PURPOSE: Testicular intraepithelial neoplasia (TIN; or carcinoma in situ of the testis) is the precursor of testicular germ-cell tumours (GCT). It is detected by conventional surgical biopsy of the testis. To date, only little information is available in regard to the accuracy of the biopsy. False-negative biopsies have been reported only sporadically. PATIENTS AND METHODS: Twenty-one patients who developed a testicular GCT despite a testicular biopsy negative for TIN were analysed clinically and histologically. The median age of the patients is 34 years. The median interval from biopsy to the clinical appearance of GCT is 39 months. Four of the 21 patients had their biopsy done within a previously reported multicentric study (n=1859 cases with negative biopsy including five cases with false-negative biopsy hitherto known). All of the biopsy specimens were re-examined immunohistologically. In 15 cases, the orchiectomy specimens were re-examined for the presence of TIN in the tumour-surrounding tissue. RESULTS: In five cases, TIN was found in the biopsy specimen upon re-examination. In all of the 15 orchiectomy specimens there was evidence of TIN in the tissue adjacent to the tumour. In three biopsy specimens there were microcalcifications in the seminiferous tubules. Severe impairment of the spermatogenesis was observed histologically in only 3 of the 21 patients. The relative proportion of false-negative biopsies is 0.5% (95% confidence intervals (CI): 0.22%; 0.92%). The sensitivity of the biopsy to detect TIN is 0.914 (95% CI: 0.842; 0.959) and the overall accuracy is 0.995 (95% CI: 0.991; 0.9979). A total of 44 false-negative biopsies are reported to date. CONCLUSIONS: False-negative biopsies for TIN do occur but the proportion is only 0.5%. There is no clear-cut clinical nor histological feature associated with false-negative biopsies. However, young age (i.e. <18 years) and intratubular microcalcifications should increase the clinician's and pathologist's vigilance. The majority of false-negative biopsies are caused by the non-random distribution of TIN in the testis while some few cases are caused by technical problems. Two-site biopsies would probably increase the accuracy of the biopsy in high risk cases.

Adolescent↗

(Salen)tin complexes: syntheses, characterization, crystal structures, and catalytic activity in the formation of propylene carbonate from CO(2) and propylene oxide.

A series of (salen)tin(II) and (salen)tin(IV) complexes was synthesized. The (salen)tin(IV) complexes, (salen)SnX(2) (X = Br and I), were prepared in good yields via the direct oxidation reaction of (salen)tin(II) complexes with Br(2) or I(2). (Salen)SnX(2) successfully underwent the anion-exchange reaction with AgOTf (OTf = trifluoromethanesulfonate) to form (salen)Sn(OTf)(2) and (salen)Sn(X)(OTf) (X = Br). The (salen)Sn(OTf)(2) complex was easily converted to any of the dihalide (salen)SnX(2) compounds using halide salts. All complexes were fully characterized by (1)H NMR spectroscopy, mass spectrometry, and elemental analysis, while some were characterized by (13)C, (19)F, and (119)Sn NMR spectroscopy. Several crystal structures of (salen)tin(II) and (salen)tin(IV) were also determined. Finally, both (salen)tin(II) and (salen)tin(IV) complexes were shown to efficiently catalyze the formation of propylene carbonate from propylene oxide and CO(2). Of the series, (3,3',5,5'-Br(4)-salen)SnBr(2), 3i, was found to be the most effective catalyst (TOF = 524 h(-)(1)).

Journal Article↗

Retinoic acid in association with tin-metalloporphyrins influences heme metabolism in vivo in rats.

In the current study we report the perturbation of key enzymes of the heme metabolic pathway, i.e. delta-amino levulinic acid synthase, heme oxygenase and biliverdin reductase, in vivo by administration of retinoic acid (RA) and retinoic acid in association with tin-metalloporphyrins, viz., tin-protoporphyrin (SnPP) and tin-mesoporphyrin (SnMP) in the liver, spleen, heart and lung of rats. RA at a dosing regimen of 50,000 I.U. stimulated splenic ALA-S activity, whereas co-administration of tin-metalloporphyrins with RA antagonised the RA mediated induction of ALA-S. In the other tissues viz., liver, heart and lung our results showed a diminution of ALA-S activity on RA administration, the level of repression was further attenuated when tin-metalloporphyrins were co-administered with RA. This marked suppression of ALA-S brought forth by concurrent administration of RA and tin-metalloporphyrins is suggestive of the beneficial effect of this formulation in acute attacks of porphyria, similar to heme. Furthermore, our results emphasize that the combined dosing of RA with tin-metalloporphyrins leads to a substantial decline in bilirubin levels due to a profound inhibition of HMOX in the probed tissues. The features of the combined action of RA and tin-metalloporphyrins in vivo lead to a substantial suppression of formation of the potentially toxic metabolite bilirubin, and the enhancement of disposal of the untransformed substrate (heme) of the enzyme that is inhibited. These results define some of the characteristics of a therapeutically useful formulation and represent a new therapeutic approach for the amelioration and management of hyperbilirubinemia.

5-Aminolevulinate Synthetase↗

Detection of tubulointerstitial nephritis antigen (TIN-ag) in Lewis rat.

Tubulointerstitial nephritis antigen (TIN-ag) is a recently described basement membrane component reactive with autoantibodies in some forms of autoimmune mediated tubulointerstitial nephritis. Immunofluorescence studies using polyclonal and monoclonal antibodies have indicated a restrictive tissue distribution for TIN-ag, with the site of most prominent expression the kidney tubular basement membrane. However, Lewis rat does not demonstrate any immunoreactivity for TIN-ag and does not develop tubuloinsterstitial nephritis after injection of tubular basement membrane material. As TIN-ag would appear to be a molecule of biological significance, experiments were designed to explore the presence or absence of this macromolecule in the Lewis rat model. Southern blotting of Lewis rat genomic DNA revealed the presence of gene sequences corresponding to TIN-ag. RTPCR analysis of Lewis rat kidney cortex total RNA illustrated the expression of a TIN-ag gene product. Western blotting demonstrated the presence of TIN-ag protein forms in kidney cortical homogenates of Lewis rat. The data suggest either extensive epitope masking or expression polymorphism of TIN-ag in the Lewis rat.

Animals↗

Tin foil as bolus material for therapeutic electron beams from the Varian Clinac 2100C/D.

Tin foils of sub-millimetre thickness have been investigated as bolus material for therapeutic electron beams from the Varian Clinac 2100C/D linear accelerator. Measurements with ionisation chamber and radiographic film in Plastic Water or water were performed under tin foil bolus to determine surface dose, therapeutic ranges, output factor correction, penumbra and dose outside the field edge. Appropriate thicknesses of tin foil for 90% dose at the surface were found to be approximately 0.3 mm for 6 MeV, and 0.4 mm for 9 MeV and 12 MeV. Enhanced therapeutic interval with tin foil bolus over water-equivalent bolus has previously been reported, but was found not to be evident for 12 MeV and for a small (4 x 4 cm2) 9 MeV field. The penumbra width of fields with tin foil and water-equivalent bolus were found to be within 2 mm, while the doses at 1 cm outside the field edge were within 1.5% of peak dose. Output factor corrections for fields with tin foil were measured as within 2% of unity. Air gaps between the tin foil and phantom surface up to 5 mm were observed to have minimal effect on output correction factor, relative surface dose, and therapeutic range.

Dose-Response Relationship, Radiation↗