Chelation in medicine

Persistence of Crystals in Stored Synovial Fluid Samples

Objective.

Lack of access to polarized light microscopy is often cited as an argument to justify the clinical diagnosis of crystal-related arthritis. We assessed the influence of time since sampling and preservation methods on crystal identification in synovial fluid (SF) samples under polarized light microscopy.

Methods.

This was a prospective, longitudinal, observational factorial study, analyzing 30 SF samples: 12 with monosodium urate (MSU) crystals and 18 with calcium pyrophosphate (CPP) crystals. Each SF sample was divided into 4 subsamples (120 subsamples in total). Two were stored in each type of preserving agent, heparin or ethylenediamine tetraacetic acid (EDTA), at room temperature or at 4°C. Samples were analyzed the following day (T1), at 3 days (T2), and at 7 days (T3) by simple polarized light microscopy, and the presence of crystals was recorded.

Results.

The identification of crystals in the MSU group was similar between groups, with crystals observed in 11/12 (91.7%) room temperature samples and in 12/12 (100%) refrigerated samples at T3. Identification of CPP crystals tended to decrease in all conditions, especially when preserved with EDTA at room temperature [12/18 (66.7%) at T3], while less reduction was seen in refrigerated heparin-containing tubes.

Conclusion.

Preserving samples with heparin in refrigerated conditions allows delayed microscopic examination for crystals. Avoiding crystal-proven diagnosis because of the immediate unavailability of microscopy no longer appears justified.

Metal complexes of ONO donor Schiff base ligand as a new class of bioactive compounds: synthesis, characterization and biological evolution

Present work reviews that, the synthesis of (E)-N'-((7-hydroxy-4-methyl-2-oxo-2H-chromen-8-yl)methylene)benzohydrazide [L] ligand and their metal complexes. The colored complexes were prepared of type [M(2+)L]X2, where M(2+)=Mn, Co, Ni, Cu, Sr and Cd, L=(7-hydroxy-4-methyl-2-oxo-2H-chromen-8-yl)methylene)benzohydrazide, X=Cl(-). Ligand derived from the condensation of 8-formyl-7-hydroxy-4-methylcoumarin and benzohydrazide in the molar ratio 1:1 and in the molar ratio 1:2 for metal complexes have been prepared. The chelation of the ligand to metal ions occurs through the both oxygen groups, as well as the nitrogen atoms of the azomethine group of the ligand. Reactions of the Schiff base ligand with Manganese(II), Cobalt(II), Nickel(II), Copper(II), Strontium(II), and Cadmium(II) afforded the corresponding metal complexes. The structures of the obtained ligand and their respective metal complexes were elucidated by infra-red, elemental analysis, Double beam UV-visible spectra, conductometric measurements, magnetic susceptibility measurements and also thermochemical studies. The metal complex exhibits octahedral coordination geometrical arrangement. Schiff base ligand and their metal complexes were tested against antioxidants, antidiabetic and antimicrobial activities have been studied. The Schiff base metal complexes emerges effective α-glucosidase inhibitory activity than free Schiff base ligand.

Antitumour metal compounds: more than theme and variations

Triggered by the resounding success of cisplatin, the past decades have seen tremendous efforts to produce clinically beneficial analogues. The recent achievement of oxaliplatin for the treatment of colon cancer should, however, not belie the imbalance between a plethora of investigated complexes and a very small number of clinically approved platinum drugs. Strategies opening up new avenues are increasingly being sought using complexes of metals other than platinum such as ruthenium or gallium. Based on the chemical differences between these metals, the spectrum of molecular mechanisms of action and potential indications can be broadened substantially. Other approaches focus on complexes with tumour-targeting properties, thereby maximizing the impact on cancer cells and minimizing the problem of adverse side effects, and complexes with biologically active ligands.

The First Ruthenium-Based Paullones: Syntheses, X-ray Diffraction Structures, and Spectroscopic and Antiproliferative Properties in Vitro

Two novel paullone derivatives, namely, 6-(alpha-picolylamino)-7,12-dihydroindolo[3,2-d][1]benzazepine (L1) and 9-bromo-6-(alpha-picolylamino)-7,12-dihydroindolo[3,2-d][1]benzazepine (L2), have been prepared. The reaction of cis-[RuCl2(DMSO)4] (DMSO=dimethyl sulfoxide) with L1 and L2 in a 1:1 molar ratio in dry ethanol at 50 degrees C afforded the complexes trans-[RuIICl2(DMSO)2L1] (1a) and trans-[RuIICl2(DMSO)2L2] (1b) in 26 and 30% yield, respectively. The reaction carried out from the same starting compounds in a 1:2 molar ratio at 75 degrees C led to the formation of [RuIICl(DMSO)(L1)2]Cl (2a) and [RuIICl(DMSO)(L2)2]Cl (2b) in 16 and 23% yield, correspondingly. The products were characterized by elemental analysis, one- and two-dimensional NMR spectroscopy, electrospray ionization mass spectrometry, IR spectroscopy, electronic spectra, cyclic voltammetry, and X-ray crystallography (L1, L2, 1a, and 2b). Complexes 2a and 2b exhibit remarkable antiproliferative activity in three human carcinoma cell lines, A549 (non-small cell lung carcinoma), CH1 (ovarian carcinoma), and SW480 (colon carcinoma). The novel complexes show an intercalative mode of interaction with DNA, which may render them attractive alternatives to metal compounds with a coordinative mode of interaction.

Synthesis, characterization and antitumor studies of transition metal complexes of o-hydroxydithiobenzoate

o-Hydroxydithiobenzoate (o-HOdtb) forms complexes, [Ni(o-HOdtb)(o-HOdtbS)], [Cu(o-Odtb)], [Co(o-HOdtb)(3)], [Fe(2)(o-Odtb)(3)], [Bu(n)(4)N][V(o-Odtb)(3)] and [Bu(n)(4)N][Zn(o-HOdtb)(3)] which were characterized by analyses and physicochemical studies. The bonding sites of o-HOdtb and the geometry of the complexes were determined by magnetic susceptibility, IR, ESR, NMR, Mössbauer and electronic spectral data. The structure of [Bu(n)(4)N][Zn(o-HOdtb)(3)] and H(2)C(o-HOdtb)(2) were assigned by single crystal X-ray diffraction studies. The monomeric complex [Bu(n)(4)N][Zn(o-HOdtb)(3)] crystallizes in Pna2(1) space group. The Mössbauer spectra of [Fe(2)(o-Odtb)(3)] at 298 and 80K suggest the presence of high spin iron(III) with an S=5/2 state. All the metal complexes were observed to inhibit the growth of tumor in vitro, whereas, ligand did not. In vivo administration of these complexes resulted in prolongation of survival of tumor-bearing mice. Tumor bearing mice administered with metal complexes showed reversal of tumor growth associated induction of apoptosis in lymphocytes. The paper discusses the possible mechanisms and therapeutic implication of the ligand and its metal complexes in tumor regression and tumor growth associated immunosuppression.

99mTc-diflunisal and the human iris: topical application reveals localization

Following the instillation of a drug into the eye, drainage mechanisms will commence at once. In this report, an attempt was made to assess the dynamics of an instilled nonsteroidal anti-inflammatory drug (NSAID), diflunisal, labeled with 1 MBq 99mTc followed by twenty minutes of scintigraphy. The results obtained with this labeled drug were compared with instillation of the same volume and activity of 99mTcO4-. Although the pertechnetate anion is an excellent and innocuous indicator for detecting the external lacrimal drainage system of the eye, it cannot visualize the internal structures. A clear scintigraphic difference was noted between labeled diflunisal and the pertechnetate anion. Scintigraphic activity surrounding the pupil of the eye provides evidence of visualization of the iris/ciliary body. This seems reasonable as the cyclooxygenase enzyme is located in this structure, and NSAIDs exert their mechanism of action via this complex. With this technology, visualization of some internal structures of the eye may be facilitated.

Effect of a chelating drug on balance and tissue distribution of four essential metals

Numerous drugs have structures that suggest that they and/or their metabolites are chelating agents, and therefore might affect trace metal metabolism. Ethambutol, used therapeutically in the treatment of tuberculosis, is an example. The objective of this study was to determine the effects of ethambutol on tissue concentrations and balance of 4 essential trace metals: copper, iron, manganese, and zinc. Eighteen male Sprague-Dawley rats (148 +/- 7 g) were housed individually in metabolic cages. Six rats received ethambutol (400 mg/kg/day) via the drinking water. There were 2 control groups of 6 rats each, an ad-lib and a pair-fed group. Iron concentrations in kidney, liver, heart, and spleen were significantly increased in both the pair-fed and ethambutol-dosed rats, an effect related to reduced food intake. However, the total iron content of these organs was comparable to that of the ad-lib controls, suggesting retention of iron by these organs with reduced food intake during growth. Trace element balance was not affected by ethambutol administration. Ethambutol produced significant decreases in heart copper, kidney zinc, plasma zinc, and liver copper and zinc not due to the associated reduced food intake. The latter results support the hypothesis that chelating drugs may alter trace metal metabolism.

Anti-inflammatory activity of a dermally applied copper salicylate preparation (Alcusal)

In rats, dermal (dorsum) application of an ethanolic copper salicylate complex (ECS) in ethanol with glycerol (Alcusal) effectively suppressed established polyarthritis, carrageenan-induced paw oedema and the inflammatory response to hydroxylapatite microcrystals. These responses appear to be due to some degree of synergism between the copper(II) and salicylate, i.e. not solely due to either species alone. Evidence for transdermal absorption of 64Cu from 64Cu-ECS is provided. Some safety aspects of this novel drug are discussed.

Karyotyping of single human chromosomes from dry mass determined by electron microscopy

Human chromosomes from cultures of peripheral lymphocytes were prepared for electron microscopy by surface spreading and critical-point drying. Total and partial determinations of chromosomal dry mass were made from contrast in electron microscopic negatives. The distribution of dry weights was analyzed with respect to the Denver-Chicago classifications. There is considerable variability of mass within each group, but no statistically significant differences between four donors. A single chromosome can be correctly classified from its total mass and the ratio of long- to short-arm mass.

Cesar: cervical smear analyser and reader. A new approach to evaluating cells in cytological preparations

Cesar presents an automated multiparameter approach to pattern recognition in the rapid detection of malignant cells from cervical and other cancers. Cells are cybernetically classified. They are collected into a container into which a nuclear stain may be incorporated and laid as a track on 35 mm. film using a disposable mapping pen device. The film track (Cytotrack) may be scanned using conventional optics and provision may be made for electronic sensing devices measuring a number of parameters, some of which are not normally used in conventional microscopy.