Antonio Claudio Tedesco

Bio: Antonio Claudio Tedesco is an academic researcher from University of São Paulo. The author has contributed to research in topics: Photodynamic therapy & Photosensitizer. The author has an hindex of 44, co-authored 307 publications receiving 6778 citations. Previous affiliations of Antonio Claudio Tedesco include Anhui University & Harvard University.

Photophysical studies of zinc phthalocyanine and chloroaluminum phthalocyanine incorporated into liposomes in the presence of additives

Abstract: The photophysical properties of zinc phthalocyanine (ZnPC) andchloroaluminum phthalocyanine (AlPHCl) incorporated into lipo-somes of dimyristoyl phosphatidylcholine in the presence and absenceof additives such as cholesterol or cardiolipin were studied by time-resolved fluorescence, laser flash photolysis and steady-state tech-niques. The absorbance of the drugs changed linearly with drugconcentration, at least up to 5.0 µM in homogeneous and heteroge-neous media, indicating that aggregation did not occur in these mediawithin this concentration range. The incorporation of the drugs intoliposomes increases the dimerization constant by one order of magni-tude (for ZnPC, 3.6 x 10 4 to 1.0 x 10 5 M -1 and for AlPHCl, 3.7 x 10 4 to 1.5 x 10 5 M -1 ), but this feature dose does not rule out the use of thiscarrier, since the incorporation of these hydrophobic drugs into lipo-somes permits their systemic administration. Probe location in bio-logical membranes and predominant positions of the phthalocyaninesin liposomes were inferred on the basis of their fluorescence andtriplet state properties. Both phthalocyanines are preferentially dis-tributed in the internal regions of the liposome bilayer. The additivesaffect the distribution of these drugs within the liposomes, a fact thatcontrols their delivery when both are used in a biological medium,retarding their release. The addition of the additives to the liposomesincreases the internalization of phthalocyanines. The interaction of thedrugs with a plasma protein, bovine serum albumin, was examinedquantitatively by the fluorescence technique. The results show thatwhen the drugs were incorporated into small unilamellar liposomes,the association with albumin was enhanced when compared withorganic media, a fact that should increase the selectivity of tumortargeting by these phthalocyanines (for ZnPC, 0.71 x 10

Drug delivery and nanoparticles:applications and hazards

Abstract: The use of nanotechnology in medicine and more specifically drug delivery is set to spread rapidly. Currently many substances are under investigation for drug delivery and more specifically for cancer therapy. Interestingly pharmaceutical sciences are using nanoparticles to reduce toxicity and side effects of drugs and up to recently did not realize that carrier systems themselves may impose risks to the patient. The kind of hazards that are introduced by using nanoparticles for drug delivery are beyond that posed by conventional hazards imposed by chemicals in classical delivery matrices. For nanoparticles the knowledge on particle toxicity as obtained in inhalation toxicity shows the way how to investigate the potential hazards of nanoparticles. The toxicology of particulate matter differs from toxicology of substances as the composing chemical(s) may or may not be soluble in biological matrices, thus influencing greatly the potential exposure of various internal organs. This may vary from a rather high local exposure in the lungs and a low or neglectable exposure for other organ systems after inhalation. However, absorbed species may also influence the potential toxicity of the inhaled particles. For nanoparticles the situation is different as their size opens the potential for crossing the various biological barriers within the body. From a positive viewpoint, especially the potential to cross the blood brain barrier may open new ways for drug delivery into the brain. In addition, the nanosize also allows for access into the cell and various cellular compartments including the nucleus. A multitude of substances are currently under investigation for the preparation of nanoparticles for drug delivery, varying from biological substances like albumin, gelatine and phospholipids for liposomes, and more substances of a chemical nature like various polymers and solid metal containing nanoparticles. It is obvious that the potential interaction with tissues and cells, and the potential toxicity, greatly depends on the actual composition of the nanoparticle formulation. This paper provides an overview on some of the currently used systems for drug delivery. Besides the potential beneficial use also attention is drawn to the questions how we should proceed with the safety evaluation of the nanoparticle formulations for drug delivery. For such testing the lessons learned from particle toxicity as applied in inhalation toxicology may be of use. Although for pharmaceutical use the current requirements seem to be adequate to detect most of the adverse effects of nanoparticle formulations, it can not be expected that all aspects of nanoparticle toxicology will be detected. So, probably additional more specific testing would be needed.

Nanoparticles in photodynamic therapy.

Abstract: Sasidharan Swarnalatha Lucky,†,§ Khee Chee Soo,‡ and Yong Zhang*,†,§,∥ †NUS Graduate School for Integrative Sciences & Engineering (NGS), National University of Singapore, Singapore, Singapore 117456 ‡Division of Medical Sciences, National Cancer Centre Singapore, Singapore, Singapore 169610 Department of Biomedical Engineering, Faculty of Engineering, National University of Singapore, Singapore, Singapore 117576 College of Chemistry and Life Sciences, Zhejiang Normal University, Zhejiang, P. R. China 321004

Organic Reactions in Aqueous Media with a Focus on Carbon−Carbon Bond Formations: A Decade Update

Abstract: 4.2.8. Reductive Coupling 3109 5. Reaction of Aromatic Compounds 3110 5.1. Electrophilic Substitutions 3110 5.2. Radical Substitution 3111 5.3. Oxidative Coupling 3111 5.4. Photochemical Reactions 3111 6. Reaction of Carbonyl Compounds 3111 6.1. Nucleophilic Additions 3111 6.1.1. Allylation 3111 6.1.2. Propargylation 3120 6.1.3. Benzylation 3121 6.1.4. Arylation/Vinylation 3121 6.1.5. Alkynylation 3121 6.1.6. Alkylation 3121 6.1.7. Reformatsky-Type Reaction 3122 6.1.8. Direct Aldol Reaction 3122 6.1.9. Mukaiyama Aldol Reaction 3124 6.1.10. Hydrogen Cyanide Addition 3125 6.2. Pinacol Coupling 3126 6.3. Wittig Reactions 3126 7. Reaction of R,â-Unsaturated Carbonyl Compounds 3127

Production of a tissue-like structure by contraction of collagen lattices by human fibroblasts of different proliferative

Abstract: Fibroblasts can condense a hydrated collagen lattice to a tissue-like structure 1/28th the area of the starting gel in 24 hr. The rate of the process can be regulated by varying the protein content of the lattice, the cell number, or the con- centration of an inhibitor such as Colcemid. Fibroblasts of high population doubling level propagated in vitro, which have left the cell cycle, can carry out the contraction at least as efficiently as cycling cells. The potential uses of the system as an immu- nologically tolerated "tissue" for wound hea ing and as a model for studying fibroblast function are discussed.