Sulfate Agents Research Articles

ChemInform Abstract: Preparation of Trifluoroethyl‐ and Phenyl‐Protected Sulfates Using Sulfuryl Imidazolium Salts.

AbstractFor the O‐protection in carbohydrates or steroids, sulfurylimidazolium salts (II) having a methyl group at the 2‐position of the imidazole ring are in general superior sulfating agents in comparison to analogues lacking the methyl group.

Preparation of trifluoroethyl- and phenyl-protected sulfates using sulfuryl imidazolium salts

Sulfuryl imidazolium salts (SIS’s), a new class of sulfating agents, were prepared bearing the trifluoroethyl (TFE) and phenyl groups, two functionalities that have been used for the protection of sulfate monoesters, by subjecting the corresponding sulfonyl imidazoles with methyl triflate. In contrast, SIS’s bearing the electron donating neopentyl and isobutyl groups, two moieties that have also been used for the protection of sulfates, were found to be unstable and could not be isolated though SIS’s bearing electron donating aryl groups, such as a p-methoxyphenyl or p-thiomethylphenyl group were readily prepared and are stable compounds. In most instances, TFE-protected phenolic and carbohydrate sulfates were obtained in good yield by reaction of the corresponding SIS’s with steroids and carbohydrates. Phenyl-protected carbohydrates were also readily prepared using the corresponding SIS’s. Those SIS’s having a methyl group at the 2-position of the imidazole ring were, in general, superior sulfating agents to those, which lacked a methyl group at this position. The use of SIS’s to prepare TFE-protected sulfates represents a significant improvement of the previous reported procedure, which involved treating unprotected sulfates with trifluorodiazoethane. The TFE protecting group was removed from steroidal sulfates and secondary sulfates in carbohydrates in high yields using NaN 3 in warm DMF, conditions that are less vigorous than those previously reported for removing this group. Deprotection of TFE-protected 6-sulfated carbohydrates using NaN 3 in warm DMF proceeded in lower yields due to partial desulfation.

Magnesium Sulfate for Preterm Labor and Preterm Birth

Obstetric Anesthesia Digest: December 2010 - Volume 30 - Issue 4 - p 202-203 doi: 10.1097/01.aoa.0000389572.25461.49

LEAF SPRAY FERTILIZATION OF BORON AND ZINC ON PRODUCTIVITY AND FRUIT QUALITY OF JAPANESE PEAR TREE

The cultivation of fruit plants from temperate climate in tropical or subtropical regions can be a good income alternative for the producer. However, due to the little existent information about cultivation of those fruit plants, the producers use imported techniques of other producing areas, or even an association of practices used for other fruit plants, pointing out the leaf spray fertilization of micronutrients without appropriate scientific base. In this context, the objective of this study was to verify the effect of the leaf spray fertilization of B and Zn on productivity and fruit quality of Japanese pear tree. The experiment was conducted from 2004 to 2005, in Ilha Solteira, in northwestern Sao Paulo State-Brazil. The climate is, according to the Kopppen Classification, tropical wet and dry (Aw). The 'Okusankichi' cultivar, grafted on Pyrus communis L. rootstock was used as well as doses of 110 g.ha -1 of B and 250 g.ha -1 of Zn in each application. The treatments were: T1. water, T2. boric acid, T3. zinc sulfate, T4. T2 + T3, T5. boric acid + urea + citric acid + EDTA, T6. zinc sulfate + urea + citric acid + EDTA, T7. T5 + T6, T8. boric acid + urea + citric acid + EDTA + sodium molibdate + sulfur + calcium chloride, T9. zinc sulfate + urea + citric acid + EDTA + Fe sulfate + Mn sulfate + Mg sulfate and, T10. T8+T9. A randomized blocks design was used and the averages were compared by Tukey test. In the first crop the mixture of boric acid with quelating agents were efficient to supply B to the plants and zinc sulfate plus quelating agents were efficient to increase Zn leaf content. However, the productivity and the fruit quality were not influenced by the leaf spray of B and Zn. In the second crop the leaf content of B and Zn and the productivity were not influenced by the leaf spray; the boric acid and the zinc sulfate with or without quelating agents increased the contents of total soluble solids and, the boric acid with or without quelating agents increased the contents of total titratable acidity.

FT Raman investigation of novel chitosan sulfates exhibiting osteogenic capacity

Chitosan sulfates (CHS) exhibiting various total degrees of substitution ascribed to sulfate groups (DS S) were synthesized. The sulfation could be under homogeneous or non-homogeneous conditions. The obtained CHS were characterized and total DS S of up to 1.73 were determined. Using chlorosulfonic acid as sulfating agent, CS with total DS S between 0.86 and 1.67 were obtained and the total DS S can be regulated by varying the sulfation parameters. Using other sulfating agents, CS with distinct total DS S of up to 1.73 were prepared. By means of FT Raman spectroscopy, marker bands at 1070 cm −1 or 1014 cm −1 attributed to vibrations of sulfation groups can be applied for quantifying the total DS S of CHS. Calibration curves with correlation coefficients of more than 0.95 were established, suggesting the feasibility of Raman spectroscopy for quantifying the total DS S of CHS. Finally, the capacity of CHS to improve the osteogenic activity of bone morphogenetic protein-2 (BMP-2) was presented.

Adverse effects of drugs on the esophagus

Given the function of the esophagus to transport orally ingested solids and liquids into the stomach there are several medications with adverse effect on esophageal structures and function. Various pharmacologic agents can induce esophageal injury, promote gastroesophageal reflux by decreasing lower esophageal sphincter tone or affect esophageal perception and motility. The risks of bisphosphonates, doxycycline, ferrous sulfate, ascorbic acid, aspirin/NSAIDs and chemotherapeutic agents to induce esophageal lesions have been documented in case reports and short series. In addition to direct mucosal injury, many commonly used medications including nitroglycerins, anticholinergics, beta-adrenergic agonists, aminophyllines, and benzodiazepines promote/facilitate gastroesophageal reflux by reducing lower esophageal sphincter pressure. Additional evidence accumulates on the adverse effects of various medications on esophageal motility and perception. The treatment of medication-induced esophageal lesions includes (1) identifying and discontinuing the causative medication, (2) promoting healing of esophageal injury by decreasing esophageal acid exposure or coating already existing esophageal lesions, (3) eventual use of protective compounds.

Magnesium Sulfate for Preterm Labor and Preterm Birth

Approximately half of the more than 500,000 preterm births each year result from preterm labor. Tocolytic therapy continues to be the focus of treatment of these women. Although a variety of tocolytics are used in clinical practice, magnesium sulfate remains one of the most commonly used agents. Magnesium sulfate has also been the focus of recent research for its potential neuroprotective effects for neonates born preterm. Evaluation of 19 randomized clinical trials reveals that magnesium sulfate tocolysis does not reduce the frequencies of delivery within 48 hours, 7 days, or early/late preterm birth, and is not associated with improvements in newborn morbidities or mortality. No other tocolytic class resulted in improved newborn outcomes when compared with magnesium sulfate tocolysis. We conclude that it is appropriate to withhold tocolysis with magnesium sulfate or other agents from women presenting in preterm labor as newborn benefit has not been demonstrated with such treatment. If initiated to achieve time for antenatal corticosteroid administration, or for other acute reasons, treatment can be discontinued once these goals have been achieved or if labor subsides before then. Because brief pregnancy prolongation is unlikely to improve newborn outcomes after corticosteroid administration has been completed, it is appropriate to withhold magnesium sulfate tocolysis from women with recurrent preterm labor thereafter. If magnesium sulfate is given for neuroprotection, a protocol from one of the three major trials that have demonstrated benefits should be used.

Use of Colloidal Graphite Coating to Reduce Magnetic Resonance Imaging Artifacts Caused by Metallic Objects

Magnetic susceptibility mismatch, between human tissue and a foreign metallic object, is one of several factors responsible for image distortions in magnetic resonance imaging (MRI). Combining diamagnetic materials such as bismuth or carbon with paramagnetic materials such as nitinol or titanium can reduce the mismatch in bulk susceptibility of a foreign object and the surrounding tissue. Muller-Bierl et al. have succeeded in reducing MRI field distortion by coating titanium wire with bismuth. Wilson et al. used a pyrolytic graphite mouth shim to improve brain functional MRI performance. Conolly et al. have successfully used pyrolytic graphite in foam to reduce image artifacts at air-tissue interfaces. In this study, it was hypothesized that coating a metallic object with carbon particles suspended in a polymer can reduce the size of image artifacts. Four 6Al-4V titanium discs (2.3mm×9.5mm∅) were encapsulated in an epoxy-graphite mixture. Mixtures of graphite and epoxy were poured around the titanium discs in molds and allowed to cure. A specimen of titanium was encapsulated in plain epoxy to serve as the control sample. Polycrystalline graphite was mixed at mass ratios of 1:2 and 1:1 to epoxy for two of the samples. Pyrolytic graphite flakes were mixed at a 1:2 mass ratio to epoxy. The sample discs were placed in an aqueous solution of copper sulfate and gadolinium contrast agent inside a wrist imaging coil at the isocenter of a 3 Tesla MRI machine; disc axes were perpendicular to the B0 direction. A T2-weighted gradient echo MRI image was taken in the coronal plane. Echo time, relaxation time, flip angle, and phase encode direction set to 71 ms, 3430 ms, 80 degrees, and right to left respectively. The control sample produced an arrowhead artifact sweeping in the same direction as the static magnetic field vector, B0. The two samples containing powdered polycrystalline graphite produced arrowhead shaped artifacts. The direction of image distortion, however, was opposite from that of the control sample. The change in direction of the image artifact is attributed to the change in bulk magnetic susceptibility of the sample from paramagnetic behavior of titanium encapsulated in plain epoxy to a diamagnetic behavior from the added carbon powder. The titanium sample encapsulated in the pyrolytic graphite-epoxy mixture produced an artifact with irregular outline and no discernable directional bias relative to B0. The hypothesized cause for this difference in artifact shape between the polycrystalline and pyrolytic graphite samples is an increase in air bubble entrapment due to the planar structure of the pyrolytic graphite flakes during the epoxy mixing process. Further study is underway to find a specific carbon-polymer mass ratio and coating thickness that will reduce MR image artifacts that would otherwise appear due to the presence of a metallic object in the MRI region of interest. This work is supported by MIMTeC, a National Science Foundation Industry University Collaborative Research Center and by NIH Grant P30NS057091.

Effects of ingredients on thermal and mechanical properties of acrylic bone cements

AbstractThere is a very delicate relation between the amounts of all the ingredients present in the cement composition and the properties of the product. In this study, homogeneous poly(methyl methacrylate) (PMMA) microspheres were prepared by suspension polymerization technique, and used in cement formulations. Various acrylic cements with different compositions were prepared by using PMMA microspheres, methyl methacrylate (MMA) monomer, radiopaque agent of barium sulfate (BaSO4), inorganic particles of hydroxyapatite (HA), initiator and chain stopping agent of 1‐dodecyl mercaptan (DDM). The effects of these additives on mechanical and thermal properties of the resultant cements were examined. Addition of 8% HA relative to the solid parts caused an increase in both tensile and compressive strengths from 20.40 to 25.20 MPa, and from 84.04 to 89.57 MPa, respectively, while curing temperature was decreased about 3 degrees. Chain stopping agent of DDM caused a sharp decrease about 30 degrees in the curing temperature. Radiopaque agent of barium sulfate caused inverse effect on mechanical and thermal properties. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Interaction of Ionic Liquids with Polysaccharides, 8 – Synthesis of Cellulose Sulfates Suitable for Polyelectrolyte Complex Formation

Water-soluble CS with different DS were synthesized by homogeneous conversion of cellulose (microcrystalline cellulose and spruce sulfite pulp) with different sulfating agents in the ionic liquids BMIMCl, AMIMCl and EMIMAc. N,N-Dimethylformamide was used as a dipolar aprotic co-solvent in order to improve the miscibility of the reaction mixture. The CS prepared by the new homogeneous reaction pathway were studied towards the formation of PEC capsules. CS obtained from SSP formed mechanically stable PEC capsules with PolyDADMAC. Exploiting this method, the microencapsulation of glucose oxidase was studied and enzyme activity tests were performed with encapsulated GOD.

Effects of Pulmonary Aspiration of Barium Sulfate or Various Gelling Agents for Jelly Foods on Lung Tissue and Pulmonary Function in Rats

Effects of Pulmonary Aspiration of Barium Sulfate or Various Gelling Agents for Jelly Foods on Lung Tissue and Pulmonary Function in Rats

Office-Based Management of Urticaria

Urticaria is a common pruritic skin disorder that is often seen in the office and varies in severity and chronicity. The etiologic cause is frequently not identifiable. Urticaria may be associated with physical factors and triggers, including foods or medications. A significant percentage of patients with chronic urticaria have circulating autoantibodies directed toward immunoglobulin-E or the high-affinity receptor for immunoglobulin-E (FcεRI), or have antithyroid antibodies that might play a role in the activation of the final common pathway in urticaria: mast cell activation and degranulation. Management begins with a careful investigation and elimination of eliciting factors when identified, followed by treatment of underlying disease. Antihistamines are the current mainstay of pharmacotherapy for urticaria, which provide symptomatic relief in most cases. In severe cases, corticosteroids, hydroxychloroquine sulfate (Plaquenil; Sanofi-Synthelabo, New York, NY), and immunosuppressive agents, including cyclosporin, are sometimes used by specialists.

A Double Chain Metal‐organic Framework Constructed by Tetrameric Nickel(II) Units and 1,3,5‐Benzenetricarboxylic Trianions

AbstractHydrothermal reaction of nickel sulfate, 1,3,5‐benzenetricarboxylic acid and deprotonation agent ethylenediamine yields a metal‐organic framework [Ni4(μ3‐OH)2(H2O)10(BTC)2]·H2O, which consists of double chains constructed from tetrameric nickel(II) units and 1,3,5‐benzenetricarboxylic trianions. Hydrogen bonds and π‐π stacking interactions among these chains result in the three‐dimensional structure of the compound. Magnetic study reveals there are ferromagnetic interactions among the Ni2+ ions of each Ni4 units in the compound.

Chemical characterization of the inorganic fraction of aerosols and mechanisms of the neutralization of atmospheric acidity in Athens, Greece

Abstract. The PM10 mass concentration levels and inorganic chemical composition were determined on 12-h resolution sampling during August 2003 and March 2004, in the centre of Athens, Greece. The August 2003 campaign mean PM10 mass concentration, obtained by Beta Attenuation at 5 m above ground in Athinas Street, was 56 μg m−3 while the corresponding value for March 2004 was 92 μg m−3. In both campaigns the E.U. imposed daily limit of 50 μg m−3 was exceeded on several days. During the March campaign, in Athinas Street, additionally obtained DSFU-PM10 (PM10-2.5+PM2.5) gravimetric mass concentrations (mean: 121 μg m−3) in the "breathing zone", at 1.5 m above ground were significantly higher compared to the respective mean PM10 mass concentrations obtained by the same method at 25 m above ground, in a second site (AEDA; mean: 86 μg m−3) also in the centre of the city. The above findings suggest that, for a realistic estimation of the exposure of citizens to particulate matter, PM10 sampling in the "breathing zone" (1.5–3 m above ground) is necessary. Such data are presented for the first time for the centre of Athens. In both campaigns, calcium was found to be the predominant component of the coarse fraction while crust-related aluminosilicates and iron were the other major components. The above elements constitute the most important components of the fine fraction, together with the predominant sulphur. All toxic metals were found in concentrations below the established air quality limits, and most of them in lower concentrations compared to older studies. Lead in particular, appeared mostly in the fine fraction and in very low concentrations compared to studies dating more than a decade back. The predominant ions of the coarse fraction have been found to be Ca2+, NO3−, Na+ and Cl−, while SO42−, Ca2+ and NH4+ were the major ionic components of the fine fraction. In the fine particles, a low molar ratio of NH4+/SO42− indicated an ammonium-poor ambient air, and together with inter-ionic correlations suggested that atmospheric ammonia is the major neutralizing agent of sulfate, while being insufficient to neutralize it to full extend. The formation of NH4NO3 is therefore not favored and additional contribution to the neutralization of acidity has been shown to be provided by Ca2+ and Mg2+. In the coarse particle fraction, the predominantly abundant Ca2+ has been found to correlate well with NO3− and SO42−, indicating its role as important neutralizing agent in this particle size range. The proximity of the location under study to the sea explains the important concentrations of salts with marine origin like NaCl and MgCl2 that were found in the coarse fraction, while chloride depletion in the gaseous phase was found to be limited to the fine particulate fraction. Total analyzed inorganic mass (elemental+ionic) was found to be ranging between approximately 25–33% of the total coarse particle mass and 35–42% of the total fine particle mass.

Introduction of 2,2,2‐Trichloroethyl‐Protected Sulfates into Monosaccharides with a Sulfuryl Imidazolium Salt and Application to the Synthesis of Sulfated Carbohydrates

Sweet sulfur: Sulfuryl imidazolium salt 1 represents a new class of highly potent sulfating agents and is very effective for introducing trichloroethyl-protected sulfates into monosaccharides for the synthesis of sulfated oligosaccharides (see scheme; NMI=N-methylimidazole, OTf=triflate, PG=protecting group, TCE=2,2,2-trichloroethyl).

Synthesis of galactomannan sulfates

The experimental conditions for the sulfation of legume galactomannans were found, which allow for the obtainment of polysaccharides with a high degree of substitution. Sulfate esters of four galactomannans of different composition (galactose content, 16.4-47.5%) were synthesized using the SO3-pyridine complex in dimethylformamide as a sulfating agent. The degree of substitution was as high as 1.4-1.8; it did not correlate with the content of galactose in the polysaccharides. It was found that the degree of sulfation depended on the reaction temperature in the range of 19-60 degrees C.

Chondroitin Sulfate and Sulfur Containing Chondroprotective Agents: Is there a Basis for their Pharmacological Action?

Chondroitin sulfate, glucosamine sulfate and other sulfur containing compounds are widely used by individuals afflicted with joint pains. In spite of their incremental use, neither their efficacy nor their mode of action has been defined. Metabolic studies indicate that these compounds are degraded prior to absorption or shortly thereafter into their fundamental constituents: simple carbohydrates and inorganic sulfate. Polysaccharides cannot be reutilized as such, and inorganic sulfate can only be incorporated into cartilage glycosaminoglycans (GAG) following de novo activation. The carbohydrate moiety of GAG can, under normal circumstances, be readily synthesized by cells. If these compounds, rich in sulfur, are exhibiting any pharmacological effects, they are most likely doing so solely because of their ability to contribute this important element to our organism. Sulfur is normally derived from methionine and cysteine in proteins. Very little is derived from other dietary sources. The minimal daily requirements for this important mineral have never been established in spite that in addition to being essential for GAG synthesis, it is a structural component of glutathione and other key enzymes, coenzymes and metabolites that play fundamental roles in cellular homeostasis and control of inflammation. It is therefore not unlikely that any beneficial effect of these dietary supplements results from their ability to supplement our diet with a source of inorganic sulfur. Keywords: Sulfur, chondroitin sulfate, arthritis, chondrocyte, cartilage, glutathione, glycosaminoglycans

The effects of magnesium sulfate on fetal rats of FGR and the expression of caspase-3 in the placenta of maternal rat

To investigate the effect of magnesium sulfate on the fetal rats of FGR and the expression of caspase-3 in the placenta of maternal rat; To explore the mechanism of using magnesium sulfate to cure the FGR. Establish model of FGR by a way of passive smoking: giving the maternal rats different agent of magnesium sulfate by subcutaneous injection: low agent group (300 mg/kg), high agent group (600 mg/kg). Concentration of magnesium sulfate was monitored. The expression of caspase-3 was measured by RT-PCR and immunohistochemistry technology. Both of the concentrations of magnesium sulfate in high and low agents group are higher than the FGR group (P < 0.01); the weight of the placenta and fetal rat in high agent group are higher than the FGR group (P < 0.05 and P < 0.01); the expression of mRNA and protein of caspase-3 in the two agent group is higher than the FGR group (P < 0.05 respectively); concentration of magnesium sulfate in the maternal rat blood correlate to the weight of fetal rat (r = 0.899, P = 0.038) and the expression of caspase-3 in the placenta of maternal rat (r = -0.747, P = 0.033; r = - 0.915, P = 0.001). The research suggests that the weight of fetal rat could be increased by treatment of magnesium sulfate. Because it would imfrmove the placental function by depressing the expression of caspase-3.

Effect of CeO 2 on the textural and acid properties of ZrO 2–SO 42−

The effect of the incorporation of CeO 2 in ZrO 2–SO 4 2− was studied. Materials were synthesized by the sol–gel method with varying CeO 2 content (10, 20 and 30%). Sample sulfation took place in situ, maintaining the amount of sulfate at 20 wt.% using concentrated H 2SO 4 and a 1 M (NH 4) 2SO 4 solution as the sulfating agents. These catalytic materials were characterized by X-ray diffraction, nitrogen adsorption (Brunauer–Emmett–Teller (BET) method), potentiometric titration with n-butylamine (NBTA) and dehydration of 2-propanol. The ZrO 2–SO 4 2− showed specific high areas (160 and 122 m 2/g), which decreased with increasing CeO 2 content. There was no significant effect of CeO 2 on the tetragonal structure of ZrO 2–SO 4 2−, perhaps because the quantities of CeO 2 incorporated were too low to affect the crystalline properties of the material. The acidity of ZrO 2–SO 4 2− decreased with increasing weight percentage of CeO 2; however, the materials showed sufficient acidity and adequate specific area for the dehydration of 2-propanol at low temperatures (80 °C).

Nondegradative Sulfation of Polysaccharides. Synthesis and Structure Characterization of Biologically Active Heparan Sulfate Mimetics

Reproducible and nondegradative preparation of sulfated molecules exhibiting diverse biological properties requires caring out sulfation reactions under ready controlled mild conditions. Although, to date, sulfur trioxide is the most used sulfation agent, its highly acid character has brought its use in association with different nitrogen bases as sulfur trioxide−nitrogen base complexes and/or by introduction of basic solvents as pyridine. We have applied sulfur trioxide and other sulfation agents including protocols for the synthesis of biologically active sulfated polysaccharides and demonstrated that these agents provoke cleavage of glycosidic bonds and other acid labile functions as amides, esters and even ethers. These facts prompted us to develop new reaction conditions for a general and nondestructive sulfation protocol. Our approach consists of the introduction of 2-methyl-2-butene as an acid scavenger of neutral character. Application of the method leads to an efficient, reproducible, and controlled synthesis of acid labile dextran derivatives well-known to be active in tissue repair and recently proposed for example as a new therapeutic agent for prion diseases. A novel 1H NMR structural analysis of this kind of macromolecules is presented. This method offers a new advance for more efficient synthesis of biologically active sulfated macromolecules.