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PubMed2005

Inorganic-organic hybrids of the p,p'-diphenylmethylenediphosphinate, pcp2-. Synthesis, characterization, and XRPD structures of [Sn(pcp)] and [Cu(pcp)].

Two new inorganic-organic polymeric hybrids [Sn(pcp)] and [Cu(pcp)], pcp=CH2(PhPO2)2(2-), have been synthesized and structurally characterized. The tin derivative has been obtained by reaction of the p,p'-diphenylmethylenediphosphinic acid (H2pcp) in water with SnCl2.2H2O, while the copper derivative has been synthesized through a hydrothermal reaction from the same H2pcp acid and Cu(O2CMe)2.H2O. The structures of these compounds have been solved "ab initio" by X-ray powder diffraction (XRPD) data. [Sn(pcp)] has a ladder-like polymeric structure, with tin(II) centers bridged by diphenylmethylenediphosphinate ligands, and alternating six- and eight-membered rings. The hemilectic coordination around the metal shows the tin(II) lone pair to be operative, resulting in significant interaction mainly with a C-C bond of one phenyl ring. The [Cu(pcp)] complex displays a polymeric columnar structure formed by two intersecting sinusoidal ribbons of copper(II) ions bridged by the bifunctional phosphinate ligands. The intersections of the ribbons are made of dimeric units of pentacoordinated copper ions. Crystal data for [Sn(pcp)]: monoclinic, space group P2(1)/c, a=11.2851(1), b=15.4495(6), c=8.6830(1) A, beta=107.546(1) degrees, V=1443.44(9) A, Z=4. Crystal data for [Cu(pcp)]: triclinic, space group P, a=10.7126(4), b=13.0719(4), c=4.9272(3) A, alpha=92.067(5), beta=95.902(7), gamma=87.847(4) degrees, V=685.47(7), Z=2. The tin compound has been characterized by 119Sn MAS NMR (magic-angle spinning NMR), revealing asymmetry in the valence electron cloud about tin. Low-temperature magnetic measurements of the copper compound have indicated the presence of weak antiferromagnetic interactions below 50 K.

Journal Article↗
PubMed2004

A stable distannirane.

The first three-membered ring compound containing two tin and one carbon atoms, 1,1,2,2-tetra(2,4,6-triisopropylphenyl)-3-fluorenylidene-1,2-distannirane, has been synthesized in a two-step procedure from the 9-[bis(2,4,6-triisopropylphenyl)fluorostannyl]chloromethylenefluorene.

Journal Article↗
PubMed2002

Synthesis and antimycobacterial activity of 6-arylpurines: the requirements for the N-9 substituent in active antimycobacterial purines.

6-Arylpurines carrying a variety of substituents in the 9-position were prepared by Stille coupling between appropriately substituted 6-chloropurines and aryl(tributyl)tin, and the compounds were screened for antibacterial activity against Mycobacterium tuberculosis H(37)Rv. The lowest minimum inhibitory concentration value, 0.78 microg/mL, was found for 9-benzyl-2-chloro-6-(2-furyl)purine. This compound exhibited relatively low cytotoxicity, and it was active against several singly drug-resistant strains of M. tuberculosis.

Animals↗
PubMed1983

Resonance of an unshared electron pair between two atoms connected by a single bond.

The reported structure of the dimer of a compound of bicovalent tin indicates that the tin-tin bond is of a new type. It can be described as involving resonance between two structures in which there is transfer of an electron pair from one tin atom to the other. The tin atoms are connected by a single covalent bond (each also forms two covalent bonds with carbon atoms), and an unshared electron pair resonates between the fourth sp(3) orbitals of the two atoms. Similar structures probably occur in digermene and distannene.

Journal Article↗
PubMed1985

The development and in-vivo behavior of tin containing radiopharmaceuticals--II. Autoradiographic and scintigraphic studies in normal animals and in animal models of bone disease.

Various 117mSn (2+ and 4+) compounds in well defined oxidation states were studied in normal mice using whole body autoradiography (WBARG), tissue distribution and scintigraphy in animal models of vitamin A induced bone disease, fracture, infected fracture and ischemic muscle lesions. The 117mSn4+-DTPA showed high affinity to normal bone with low soft tissue concentration. Increased deposition of this compound in fractures and ischemic lesions in muscle was also demonstrated. In hypervitaminosis A, reduced bone uptake of 117mSn4+-DTPA was shown to occur. Nude mice bearing osteogenic sarcoma of human origin showed uptake in spiculated pattern. The similar distribution of 117mSn4+-DTPA which does not contain phosphate or phosphonate groups, and the 99mTc(Sn) skeletal imaging compounds may indicate that tin is important in binding to bone. 117mSn4+-DTPA may not be ideal for routine imaging except when long term follow up is required. It should however be considered for therapy of bone tumors because of the long physical half-life of 117mSn (t1/2 = 14.03 days), abundance of short-range conversion and Auger electrons and its preferential deposition in cortical bone as indicated by our results.

Animals↗
PubMed2001

Stille couplings catalytic in tin: the "Sn-O" approach.

A one-pot tandem Pd-catalyzed hydrostannylation/Stille coupling protocol for the stereoselective generation of vinyltins and their subsequent union, employing only catalytic amounts of tin, is described. By recycling the organotin halide Stille byproduct back to organotin hydride, a hydrostannylation/cross-coupling sequence can be carried out with catalytic amounts of tin. Such a process is most effective with Me(3)SnCl serving as the tin source. This protocol allows a 94% reduction of the tin requirement, while maintaining good yields (up to 90%) for a variety of Stille products. Furthermore, since one cycle requires the tin to undergo at least four transformations, each moiety of trialkyltin is experiencing a minimum of 60 reactions over the course of the hydrostannylation/Stille sequence.

Organotin Compounds↗
PubMed1993

Comparison of tin and lead toxic action on erythropoietic system in blood and bone marrow of rabbits.

The aim of this work was to assess and compare morphological changes in blood and bone marrow of rabbits after per os (po) or intraperitoneal (ip) administration of equimolar doses of tin or lead. The experiment was performed on female rabbits that were divided into four groups of six animals each, and received stannous chloride SnCl2 x 2 H2O (Merck) or lead acetate Pb(CH3COO)2 (POCh Gliwice) in equimolar doses (ip--17/microM/kg) or per os (po--85/microM/kg). Group I was administered SnCl2 ip at the dose of 2 mg Sn/kg every day for 3 mo, group II Pb(CH3COO)2 ip at a dose of 3.5 mg Pb/kg every day for 3 wk, group III po SnCl2 (10 mg Sn/kg), and group IV po Pb(CH3COO)2 (17.5 mg Pb/kg), both for 4 mo. The morphological factors hemoglobin (Hb), hematocrit (Ht), erythrocyte (Ercs), and reticulocyte counts, MCV, MCH, MCHC, and erythropoietic system in bone marrow aspirates with sideroblast count, iron concentration, TIBC, and SI were estimated. Tin caused hemolytic anemia depending on abnormal iron utilization. After ip administration of tin, anemia was observed during the whole time of the study, whereas after po exposure, transient anemia was noticed. It has been proven that the mechanism of toxic action of tin on hematopoietic system is similar to the toxic effect of lead.

Administration, Oral↗
PubMed1982

Comparative toxicity of alkyltin and estertin stabilizers.

In a 2-wk feeding study the oral toxicities of the estertin compounds bis-(beta-carbobutoxyethyl)-tin dichloride (CBETC) and bis-(beta-carbomethoxyethyl)tin dichloride (CMETC) and their hydrolysis products bis-(beta-carboxyethyl)tin dichloride (CETC) were compared with those of the dialkyltin compounds di-n-octyltin dichloride (DOTC) and di-n-butyltin dichloride (DBTC). At a dietary level of 450 ppm the estertins did not affect weights, but at the relatively high level of 1350 ppm both caused growth retardation and a statistically significant decrease in the relative weight of the liver, while CBETC also reduced the relative weights of the thymus and spleen. A diminished amount of liver glycogen was the only treatment-related histopathological change observed in these organs. CETC caused no signs of toxicity up to a level of 1350 ppm. Slightly decreased body-weight gains were recorded in rats fed 50 ppm DBTC or 150 ppm DBTC or DOTC, but the main effect in dialkyltin-fed rats was a decrease in lymphoid-organ weights. In rats fed 150 ppm DBTC or DOTC for 2 wk, the relative thymus weight was decreased by more than 70% compared with the control value and there was lymphocyte depletion in the thymus, especially the thymic cortex, and in thymus-dependent lymphoid areas of the spleen. Parenteral exposure demonstrated a similar difference in toxicity between these groups; a single ip or iv injection of 2.5 mg DBTC/kg body weight caused a slight reduction in body-weight gain and severe thymic atrophy, whereas CBETC and CETC had no such effects even at 10 mg/kg. However, in vitro the activities of the esterins were similar to those of the dialkyltins. In lymphocyte metabolism studies, all these compounds induced a dose-dependent stimulation of glucose consumption, with maximum stimulation occurring at a level of 5 microM with DBTC and CBETC and at 120 microM with DOTC and CMETC. At higher exposure levels, glucose consumption fell sharply, oxygen consumption was reduced and lymphocyte viability was impaired. Since the dicarboxyltin compound CETC induced no signs of lymphocytotoxicity in the in vitro cell-metabolism, cell-viability or blast-transformation studies, hydrolysis of CBETC and CMETC to CETC in the rat is suggested as a possible explanation for the discrepancy between the lymphocytotoxic activity of the estertin compounds in vitro and the absence of lymphoid atrophy following in vivo exposure, and for the finding that in the rat CMETC and CBETC are much less toxic than the dialkyltin compounds DBTC and DOTC, which induce lymphocytotoxicity both in vitro and in vivo.

Animals↗
PubMed2002

Small colonic J-pouch improves colonic retention of liquids--randomized, controlled trial with scintigraphy.

PURPOSE: A small 6-cm colonic J-pouch improves stool frequency and continence, without stool evacuation problems. However, the reservoir function is not improved on physiologic studies. Hence, a scintigraphy technique was devised to study the transit of solid and liquid colonic contents in these patients. METHODS: Patients were randomly assigned to straight or colonic J-pouch anal anastomoses after ultralow anterior resection. At 1 year after surgery, they were studied by bowel questionnaire, anorectal manometry, and technetium TC 99m tin-colloid liquid test meal/I-131 microcapsule scintigraphy. In the latter, technetium TC 99m tin-colloid was ingested orally to image the colonic liquids. I-131 microcapsules taken simultaneously imaged the solid stools. After ingestion of the radioisotopes, imaging was performed at intervals of 7 to 8, 24, and 56 hours later. Two independent observers noted the presence of technetium TC 99m tin-colloid liquid and I-131 microcapsules in various areas of interest drawn over the colon. RESULTS: There were six patients (5 males, mean age, 61.5 (SE mean, 1.9) years) in the straight, and six patients (5 males, mean age, 63.2 (4.5) years) in the colonic J-pouch group. Stool frequency was more in the straight group (4.8 (0.4) vs. 3 (0.2) stools/day; P <.001). Continence, evacuation problems, and anorectal physiologic findings were not different. Technetium TC 99m tin-colloid (imaging liquids) transited significantly faster than I-131 microcapsules (imaging solids), at various areas of interest in the colon. In the colonic J-pouch patients, technetium TC 99m tin-colloid liquid was retained significantly longer in the descending colon at 24 hours (P <.05). Stool frequency was higher when technetium TC 99m tin-colloid was not retained in the descending colon at 56 hours (3.3 (0.5) vs. 4.3 (0.4) stools/day) but this did not reach statistical significance. There were no significant differences in the distribution of the ingested I-131 microcapsules between colonic J-pouch and straight groups. CONCLUSIONS: Reduced stool frequency after colonic J-pouch may be related to factors causing better retention of liquid stools in the distal colon. No difference in solid stool transit could possibly account for minimal evacuation problems in small pouches.

Aged↗
PubMed1994

Influence of aging on oral-pharyngeal bolus transit and clearance during swallowing: scintigraphic study.

The aim of the study was to determine the influence of normal aging on regional transit and the efficiency of bolus clearance during the oral and pharyngeal phases of swallowing. We compared scintigraphically derived oral-pharyngeal transit times and isotope clearance during swallowing in 21 healthy aged volunteers (mean age 68 +/- 8 yr) and 9 young controls (mean age 28 +/- 7.5 yr). Subjects swallowed 5- and 10-ml water boluses mixed with 30 MBq 99mtechnetium tin colloid. Oral and pharyngeal transit times, pharyngeal clearance time, and postswallow residual counts in each region were derived from time-activity curves. Pharyngeal residual counts were significantly greater in the aged than in controls (P = 0.0008), but age did not influence oral residual. Aging significantly prolonged oral transit time (P = 0.02), pharyngeal transit time (P = 0.0004), and pharyngeal clearance time (P = 0.0001). We conclude that normal impairs the efficiency of pharyngeal clearance during swallowing, prolongs scintigraphic measures of oral-pharyngeal transit, and increases the exposure time of the glottis to the swallowed bolus.

Adult↗
PubMed2000

Prevention of marine biofouling using natural compounds from marine organisms.

All surfaces that are submerged in the sea rapidly become covered by a biofilm. This process, called biofouling, has substantial economic consequences. Paints containing tri-butyl-tin (TBT) and copper compounds are used to protect marine structures by reducing biofouling. However, these compounds have damaging effects on the marine environment, as they are not biodegradable. It has been noted that many seaweeds and invertebrates found in the sea are not covered by a mature biofilm. This is due to the release of compounds into the surrounding seawater that deter the settlement of fouling organisms. In addition, seaweeds and invertebrates have bacteria on their surfaces that produce compounds to deter settling organisms. The production of compounds by bacteria and their living hosts work in concert to protect the hosts' surfaces. All of these compounds can be collected so they may be natural alternatives to TBT and copper compounds. However, the benefits associated with the use of bacteria as sources of these compounds means that bacteria are the organisms of choice for obtaining natural products for antifouling coatings.

Biofilms↗
PubMed1999

The effect of trimebutine maleate on gastric emptying in patients with non-ulcer dyspepsia.

The study was designed to investigate the effect of trimebutine maleate, a drug used in both hyperkinetic and hypokinetic motility disorders, on gastric emptying in patients with non-ulcer dyspepsia having prolonged gastric emptying rates and to compare the parameters used for the determination of the lag period observed during the emptying of solid foods from the stomach. Gastric emptying was measured by the radionuclide technique. Twenty normal volunteers and 43 patients with non-ulcer dyspepsia participated in the study. Radionuclide imaging was performed by using a solid meal labeled with 99mTc-tin colloid. Of the patients with non-ulcer dyspepsia, 20 had prolonged gastric emptying. They were given three weeks of oral treatment with trimebutine maleate and had their radionuclide gastric emptying study repeated. Treatment with trimebutine maleate resulted in reduction in duration of the lag period and less retention of food at 100 minutes (p < 0.0005). After treatment with trimebutine maleate, no significant difference has been observed in the mean symptom score of patients with prolonged gastric emptying. Among the parameters used for the determination of the lag period, lag period determined by a mathematical equation (TLAG) has been found to be longer than the lag period determined by visual inspection of the images (VLAG) and there was correlation between the two parameters when the lag time was short.

Administration, Oral↗
PubMed1998

[Radionuclide scan with TC-99m-tin colloid in the evaluation of orthopedic implant infections].

We have studied 26 patients (32-77 years old, 16 females) with suspicion of joint arthroplasty infection: 11 total hip replacements, 12 total knee replacements and 3 osteosinthesys. A bone scintigraphy with MDP-99mTc, a scintigraphy with HMPAO-WBC and a scintigraphy with 99mTc-stannous colloid were made in all patients. The final diagnostic was based in joint cultures and clinic and radiologic evolution of the patients. The earliest phase of the bone scintigraphy was positive in 18 patients. The later phase was positive in all them. The WBC was positive in 20 out of 26 patients. The bone marrow scintigraphy showed a congruent pattern with WBC in 18 patients (17 infected and 1 without infection). The other ones (8 patients) showed an incongruent pattern (7 with infection and 1 without it). The results show that the bone marrow scintigraphy with 99mTc-stannous colloid improves the accuracy of the diagnostic of bone prosthesis infection and should be included into the diagnosis protocol of this disease.

Adult↗