Biomedical subjects

Griselda Polla

Publications and source records attributed to Griselda Polla.

5 recordsLinked to original sources

PubMed2006

Conformational polymorphism in bicalutamide.

Two crystalline forms (forms I and II) and an amorphous phase of bicalutamide were fully characterized through combined results of differential scanning calorimetry, X-ray powder and single crystal diffraction and Raman spectroscopy. Each polymorph crystallizes with one molecule in the asymmetric unit and the molecular conformations are quite different between them. The main difference is provided by C12-C11-S8-C5 torsion angle, which assumes a value of -88.3(4) degrees (-Syn-Clinal) and 72.5(4) degrees (+Syn-Clinal) in forms I and II, respectively. Consequently, molecules in form I show an open folding and molecules in form II a closed one. The relative stability between forms I and II is presented in an energy versus temperature diagram, where forms I and II are considered as a monotropic system, being form I the more stable one. The amorphous phase was observed very metastable and it converts to form II spontaneously at RT in around a week.

Androgen Antagonists↗

PubMed2006

Fractionation of eleven elements by chemical bonding from airborne particulate matter collected in an industrial city in Argentina.

A four-step chemical sequential extraction procedure was used to evaluate the distribution of Al, As, Cr, Cu, Fe, Mn, Ni, Pb, Ti, V and Zn in airborne particulate matter collected on glass fibre filters using a high-volume sampler. Two sets of samples were collected in 2001 (winter and summer campaigns) in representative zones of an industrial city of Argentina. The leaching scheme was applied to PM-10 particles and consisted in extracting the elements in four fractions, namely soluble and exchangeable elements; carbonates, oxides and reducible elements; bound to organic matter and sulfidic metals; and residual elements. Metals and metalloids at microg g(-1) level were determined in each fraction by inductively coupled plasma optical emission spectrometry (ICP OES). Analyte concentration varied from 14 microg g(-1) (equivalent to 1.0 ng m(-3)) for As to 11.8 mg g(-1) (equivalent to 2,089 ng m(-3)) for Al. Seven elements, namely Al, Cr, Fe, Mn, Pb, Ti and Zn showed similar distributions in both seasons while As was distributed in a significantly different manner in each season. The results exhibited low As contents in the first and second fractions that could be associated with routine coal combustion and a high content in the third and fourth fractions of the summer samples that could be linked to the use of pesticides. Aluminium, As, Cu, Mn, Ni, Ti, V and Zn were found in different percentages in the more bioavailable aqueous fraction with As, Mn, V and Zn exhibiting solubilities greater than 1% while Cr and Pb being insoluble. The content of Al, Cr, Cu, Fe, Ni, Pb, and Zn in the residual fraction was, in average, higher than 50%. A comparative assessment of the use of the underlying information available from fractionation studies compared to that obtained from total element content was done for Fe and Mn. It showed that the results obtained using chemical sequential extraction procedures allowed further discrimination of the potential air pollution sources.

Air Pollutants↗

PubMed2004

Metal fractionation of atmospheric aerosols via sequential chemical extraction: a review.

This review surveys schemes used to sequentially chemically fractionate metals and metalloids present in airborne particulate matter. It focuses mainly on sequential chemical fractionation schemes published over the last 15 years. These schemes have been classified into five main categories: (1) based on Tessier's procedure, (2) based on Chester's procedure, (3) based on Zatka's procedure, (4) based on BCR procedure, and (5) other procedures. The operational characteristics as well as the state of the art in metal fractionation of airborne particulate matter, fly ashes and workroom aerosols, in terms of applications, optimizations and innovations, are also described. Many references to other works in this area are provided.

Journal Article↗

PubMed2004

The Zn2+ salt of pamidronate: a role for water in the metal-cation binding properties of bisphosphonates.

Pamidronate (3-ammonium-1-hydroxypropylidene-1,1-bisphosphonate) is used clinically in the treatment of diseases affecting bone tissue. In the salt zinc pamidronate dihydrate, Zn(2+).2C(3)H(10)NO(7)P(2)(-).2H(2)O, pamidronate is a zwitterion with an overall charge of -1. The carbon chain adopts a trans conformation, separating maximally the positively charged N atom from the negative phosphonate groups. The Zn(2+) ion lies on an inversion center and is surrounded by a sixfold coordination sphere provided by two bidentate chelating zwitterions and two water molecules. The bidentate O.Zn.O bond angle is 92.70 (7) degrees, while the O.O bite distance is 3.018 (3) A.

Journal Article↗

PubMed2002

Fractionation of elements by particle size of ashes ejected from Copahue Volcano, Argentina.

The volcano Copahue, Neuquén province, Argentina has shown infrequent explosive eruptions since the 18th century. Recently, eruptive activity and seismicity were registered in the period July-October, 2000. As a consequence, ash clouds were dispersed by winds and affected Caviahue village located at about 9 km east of the volcano. Samples of deposited particles from this area were collected during this episode for their chemical analysis to determine elements of concern with respect to the health of the local population and its environment. Different techniques were used to evaluate the distribution of elements in four particle size ranges from 36 to 300 microm. X-ray powder diffraction (XRD) was selected to detect major components namely, minerals, silicate glass, fragments of rocks and sulfurs. Major and minor elements (Al, Ca, Cl, Fe, K, Mg, Mn, Na, S, Si and Ti), were detected by energy dispersive X ray analysis (EDAX). Trace element (As, Cd, Cr, Cu, Hg, Ni, Pb, Sb, U, V and Zn) content was quantified by inductively coupled plasma-mass spectrometry (ICP-MS). Nuclear activation analysis (NAA) was employed for the determination of Ce, Co, Cs, Eu, Hf, La, Lu, Rb, Sc, Sm, Ta and Yb. An enrichment was observed in the smallest size fraction of volcanic ashes for four elements (As, Cd, Cu and Sb) of particular interest from the environmental and human health point of view.

Argentina↗