Dithiobiureas Palladium(II) complexes' studies: From their synthesis to their biological action.

Dithiobiureas coordination chemistry towards palladium (II) ions and their possible application is presented and discussed. 1,6-(4-Methoxyphenyl)-2,5-dithiobiurea and 1,6-(4-chlorophenyl)-2,5-dithiobiurea afford two Pd(II) complexes with the general formula [Pd(HL)Cl(PPh)]. The metal ion forms one chelate ring with the dithiobiurea, and binds to a triphenylphosphine and an additional leaving group cisplatin like.

Chemical and Biological Evaluation of Thiosemicarbazone-Bearing Heterocyclic Metal Complexes.

Thiosemicarbazones (TSCNs) constitute a broad family of compounds (RRC=N-NH-C(S)- NRR), particularly attractive because many of them display some biological activity against a wide range of microorganisms and cancer cells. Their activity can be related to their electronic and structural properties, which offer a rich set of donor atoms for metal coordination and a high electronic delocalization providing different binding modes for biomolecules. Heterocycles such as pyrrole, imidazole and triazole are present in biological molecules such as Vitamine B12 and amino acids and could potentially target multiple biological processes.

New Platinum(II) Triazole Thiosemicarbazone Complexes: Analysis of Their Reactivity and Potential Antitumoral Action.

The synthesis and characterization of three new platinum complexes, with 3,5-diacetyl-1,2,4-triazole bis(4-N-isopropylthiosemicarbazone) as a ligand, are reported. The specific conditions under which solvent coordination takes place are reported and the X-ray structure of the complex with one solvent molecule of dimethyl sulfoxide is resolved. Analysis of the reactivity of these platinum compounds aids in finding the best solution profile for biological investigations.

Stability and mechanical evaluation of bovine pericardium cross-linked with polyurethane prepolymer in aqueous medium.

The present study investigates the potential use of non-catalyzed water-soluble blocked polyurethane prepolymer (PUP) as a bifunctional cross-linker for collagenous scaffolds. The effect of concentration (5, 10, 15 and 20%), time (4, 6, 12 and 24 h), medium volume (50, 100, 200 and 300%) and pH (7.4, 8.

Micro- and nanostructured hydroxyapatite-collagen microcarriers for bone tissue-engineering applications.

Novel hydroxyapatite (HA)-collagen microcarriers (MCs) with different micro/nanostructures were developed for bone tissue-engineering applications. The MCs were fabricated via calcium phosphate cement (CPC) emulsion in oil. Collagen incorporation in the liquid phase of the CPC resulted in higher MC sphericity.

Decellularization of pericardial tissue and its impact on tensile viscoelasticity and glycosaminoglycan content.

Bovine pericardium is a collagenous tissue commonly used as a natural biomaterial in the fabrication of cardiovascular devices. For tissue engineering purposes, this xenogeneic biomaterial must be decellularized to remove cellular antigens. With this in mind, three decellularization protocols were compared in terms of their effectiveness to extract cellular materials, their effect on glycosaminoglycan (GAG) content and, finally, their effect on tensile biomechanical behavior.

Biocompatibility and calcification of bovine pericardium employed for the construction of cardiac bioprostheses treated with different chemical crosslink methods.

The use of biological materials in the construction of bioprostheses requires the application of different chemical procedures to improve the durability of the material without producing any undesirable effects. A number of crosslinking methods have been tested in biological tissues composed mainly of collagen. The aim of this study was to evaluate the in vitro biocompatibility, the mechanical properties, and in vivo calcification of chemically modified bovine pericardium using glutaraldehyde acetals (GAAs) in comparison with glutaraldehyde (GA) treatment.

Propagation of tears in pericardium from young bulls: influence of the suture.

The tearing of the collagen fibers of biological materials utilized in implants or bioprostheses is an important, and sometimes early cause of the failure of these devices. We studied the force necessary to propagate a tear in a biomaterial, pericardium from young bulls, and the influence of the suture. An Elmendorf pendulum capable of measuring the force necessary to tear a given length of tissue was employed.

Side effects, complications and outcome of thoracoscopic sympathectomy for palmar and axillary hyperhidrosis in 406 patients.

Background: Thoracic sympathectomy (TS) is the treatment of choice for severe primary hyperhidrosis. However, complications, side effects and satisfaction have not been well defined.

Objective: To analyze the complications, side effects, satisfaction degree and quality of life of patients after TS for primary upper limb hyperhidrosis.

[Indicators of severity in chest trauma].

Objective: We undertook a review of patients with chest trauma attended between January 1992 and June 2005 in order to establish severity criteria in these cases.

Patients And Methods: During the study period, 1,772 cases (1,346 [76%] males) were treated, with ages ranging from 7 to 98 years (mean, 46.4 years).

Energy consumption as a predictor test of the durability of a biological tissue employed in cardiac bioprosthesis.

The mechanical behavior of the young bull pericardium in a fatigue test has been studied. This material is a similar tissue to those used in valve leaflet construction for a cardiac bioprosthesis. The consumed energy on each test was evaluated and afterwards used as a predictor of the biomaterial strength.

Elastofibroma of the thoracic wall.

Soft tissue tumors of the chest wall are rare. Between 1998 and 2007 we treated eight cases of elastofibroma of the thoracic wall, an infrequent primary tumor of the chest. Seven females and one male between 44 and 62 years presented with dorsal subscapular tumors of months and even years of evolution.

Influence of the suture in the propagation of tears in calf pericardium employed in the construction of cardiac bioprostheses.

The tearing of the fibers of biomaterials employed in implants or bioprostheses leads to early the failure of these devices. The purpose of this study was to determine the force necessary to propagate a tear in a biological tissue, calf pericardium, when sutured. We analyzed the outcome of 230 trials.

Biochemical and mechanical behavior of ostrich pericardium as a new biomaterial.

We have performed a comparative analysis of glutaraldehyde-preserved ostrich pericardium, as a novel biomaterial, with bovine pericardium. The biochemical characteristics (histology, water content, amino acid composition, and collagen and elastin contents), mechanical properties, and in vivo calcification in a subcutaneous rat model were examined. Ostrich pericardium is slightly thinner and shows a higher water content (70+/-2% vs.

Durability of a cardiac valve leaflet made of calf pericardium: fatigue and energy consumption.

We studied the mechanical behavior of membranes of calf pericardium, similar to those employed in prosthetic valve leaflets, when subjected to tensile fatigue. The objective was to assess its durability, as a fundamental property of cardiac bioprosthesis, and analyze the energy consumption. For this purpose, the authors built a hydraulic simulator to subject a spherical valve leaflet made of calf pericardium to cyclic stress mimicking cardiac function.

Tissue heart valve mineralization: Review of calcification mechanisms and strategies for prevention.

Attempts to replace diseased human valves with prostheses began more than 30 yrs ago. Heart valve prostheses can be broadly classified into mechanical prostheses (made out of non-biological materials) and bioprostheses made out of biological tissue. Biological valves are made from animal tissue bovine pericardium and porcine valves.

Resistance and stability of a new method for bonding biological materials using sutures and biological adhesives.

The valve leaflets of cardiac bioprostheses are secured and shaped by sutures which, given their high degree of resistance and poor elasticity, have been implicated in the generation of stresses within the leaflets, contributing to the failure of the bioprostheses. Bioadhesives are bonding materials that have begun to be utilized in surgery, although there is a lack of experience in their use with inert tissues or bioprostheses. Tensile testing is performed until rupture in samples of calf pericardium, a biomaterial employed in the manufacture of bioprosthetic heart valve leaflets.

Mechanical resistance of a new biomaterial, ostrich pericardium, and a new method of joining tissues combining suturing and a biological adhesive.

We studied the mechanical behavior in response to tensile stress of samples of ostrich pericardium bonded with a cyanoacrylate glue or sewn with a rectangular, overlapping suture that was subsequently sealed with the same bioadhesive. Seventy-two trials were performed in three series of 24 samples each: series AG, glued with an overlap of 1 cm2; series ASG, sewn with a rectangular, overlapping suture and sealed; and series AC, control samples that were left intact. The mean stress at rupture in series AG (glued) was 0.

Sutured calf pericardium: influence of the type and angle of the suture on mechanical behavior.

Careful selection of the biological tissue to be used in cardiac bioprostheses and a thorough knowledge of its mechanical behavior, facilitating both the prediction of this behavior and the interactions between the tissue and the other materials employed, is the best approach to designing a durable implant. For this purpose, a study involving uniaxial tensile testing of calf pericardium was carried out. Two sets of three contiguous strips of tissue were obtained from each pericardial membrane, to perform a total of 144 trials.

Calcification and identification of metalloproteinases in bovine pericardium after subcutaneous implantation in rats.

The purpose of this study was to evaluate the influence of two anticalcification pre-treatments (chloroform/methanol and ethanol) and serum conditioning of glutaraldehyde-crosslinked bovine pericardium on the calcification degree and the presence of gelatinase activities in a subcutaneous implantation model in rats. Regarding calcification of the implants, glutaraldehyde control treatments showed a significatively higher calcification degree than pericardium treated with anticalcification reagents. Serum conditioning of glutaraldehyde treated tissues did not influence the calcification degree; moreover, no differences were found in these samples with the time of implantation (30 and 90 days).

Porcine pericardial membrane subjected to tensile testing: preliminary study of the process of selecting tissue for use in the construction of cardiac bioprostheses.

The durability of cardiac bioprostheses is limited fundamentally by structural failure due to mechanical fatigue and calcification. In the present report, we analyze, using an in vitro hydraulic simulator to test tensile strength, the mechanical behavior of porcine pericardium for the purpose of establishing the criteria for selecting the biomaterial, taking into account both morphological criteria (thickness and homogeneity of the specimens) and mechanical criteria (stress at breaking point), using the epidemiological model of paired samples. The stress at breakage was found to range widely from 24.