Preparation, properties and anticancer effects of mixed As4S4/ZnS nanoparticles capped by Poloxamer 407.

Arsenic sulfide compounds have a long history of application in a traditional medicine. In recent years, realgar has been studied as a promising drug in cancer treatment. In this study, the arsenic sulfide (As4S4) nanoparticles combined with zinc sulfide (ZnS) ones in different molar ratio have been prepared by a simple mechanochemical route in a planetary mill. The successful synthesis and structural properties were confirmed and followed via X-ray diffraction and high-resolution transmission electron microscopy measurements. The morphology of the particles was studied via scanning electron microscopy and transmission electron microscopy methods and the presence of nanocrystallites was verified. For biological tests, the prepared As4S4/ZnS nanoparticles were further milled in a circulation mill in a water solution of Poloxamer 407 (0.5wt%), in order to cover the particles with this biocompatible copolymer and to obtain stable nanosuspensions with unimodal distribution. The average size of the particles in the nanosuspensions (~120nm) was determined by photon cross-correlation spectroscopy method. Stability of the nanosuspensions was determined via particle size distribution and zeta potential measurements, confirming no physico-chemical changes for several months. Interestingly, with the increasing amount of ZnS in the sample, the stability was improved. The anti-cancer effects were tested on two melanoma cell lines, A375 and Bowes, with promising results, confirming increased efficiency of the samples containing both As4S4 and ZnS nanocrystals.

Cristobalite and Hematite Particles in Human Brain.

Foreign substances get into the internal environment of living bodies and accumulate in various organs. Cristobalite and hematite particles in the glial cells of pons cerebri of human brain with diagnosis of Behhet disease with scanning electron microscopy (SEM), energy-dispersive microanalysis (EDX), and transmission electron microscopy (TEM) with diffraction were identified. SEM with EDX revealed the matter of irregular micrometer-sized particles sometimes forming polyhedrons with fibrilar or stratified structure. It was found in some particles Ti, Fe, and Zn. Some particles contained Cu. TEM and electron diffraction showed particles of cristobalite and hematite. The presence of the particles can be a result of environmental effect, disruption of normal metabolism, and transformation of physiologically iron-ferrihydrite into more stable form-hematite. From the size of particles can be drawn the long-term accumulation of elements in glial cells.

Iron and its relation to glycoconjugates in human globus pallidus.

Iron and eosinophilic, argyrophilic spheroid structures of glycoconjugates are observed in the pallido-nigral system of human and nonhuman primates. In the present study, we map the localization and distribution of ferritin and hemosiderin and their relation to neutral and acidic (sulphated and carboxylated) glycoconjugates in human globus pallidus. We investigated tissues of human globus pallidus without any motor abnormalities and psychiatric symptoms. Acidic (Alcian blue, AB pH 2.5) and neutral glycoconjugates (PAS reaction) showed spheroid deposits with the size of 5-15 µm. Staining reaction utilizing AB (pH 1.0) displays sulphated fibers and highly sulphated (AB pH 0.5) glycoconjugates round deposits. AF/AB pH 2.5 for separating sulphated from carboxylated glycoconjugates revealed the presence of both sulphated and carboxylated glycoconjugates. Perls' and Turnbull's positive reaction showed the presence of Fe(III) and Fe(II) (hemosiderin) and Ag-NOR reaction showed ferric phosphate (ferritin) deposits. Scanning electron microscope with microanalysis revealed the iron in glycoconjugates globular deposits. We suppose the presence of glycoconjugates in the samples is the result of elimination and inactivation of iron as inductor of reactive oxygen species. They can be a useful neuroprotective agent in CNS degradation (Tab. 2, Fig. 7, Ref. 44).

Iron-rich complexes in human spleen in hereditary spherocytosis.

OBJECTIVE: Tissue iron plays an important role in the development of certain diseases. Although it is one of biogenic elements, its excess induces the reactive oxygen species (ROS) formation. The aim of the present work is to examine the protection against free or loosely bound iron from the view of morphology and chemical composition of iron-rich complexes in human spleen tissues with hereditary spherocytosis (HS) by scanning and transmission electron microscope with energy-dispersive microanalysis (EDX). RESULTS: The examination of human spleen tissues by scanning and transmission electron microscope showed covering of iron-rich particles. EDX revealed many iron-rich complexes of multi-element composition in HS samples with sulphur and phosphorus as the major elements. Detection was negative in the reference samples. CONCLUSION: The covering of iron-rich particles can be explained by elimination and isolation of ferritin/iron complexes from surrounding environment to prevent the ROS formation. Sulphur, phosphorus and their compounds are probably the most significant elements that influence the ROS formation (Fig. 5, Ref. 16). Full Text in PDF www.elis.sk.

Iron accumulation in human spleen in autoimmune thrombocytopenia and hereditary spherocytosis.

BACKGROUND: Although the iron is an essential element for the physiological functions of cells, tissues and organs, it is also an important inductor of reactive oxygen species (ROS). MATERIAL AND METHODS: Three groups of human spleen with autoimmune thrombocytopenia (AITP), hereditary spherocytosis (HS) and reference samples stained by haematoxylin and eosin, Perls' reaction for nonheme Fe(III) iron and Alcian blue for glycoconjugates detection were studied. RESULTS: Positive Perls' reaction in both AITP and HS groups was seen. Higher positivity in the HS than in AITP group was observed. HS group showed a higher amount of acidic glycoconjugates deposits than AITP group. Iron overload in HS and AITP leads to overproduction of ROS. CONCLUSION: We suggest that acidic glycoconjugates deposits are involved in antioxidant defence by elimination and restriction of iron as a ROS inducer (Fig. 4, Ref. 19).

An alternative approach to carbon nanotube sample preparation for TEM investigation.

A two-stage replication technique (positive replica) is shown to be suitable for transmission electron microscopy (TEM) examination of carbon nanotubes (CNTs) and other one-dimensional nanostructures in their longitudinal direction. This method enables handling the fragile nanostructures, is fast and simple and allows to study the growth mechanism of nanofeatures, including the early stages of their growth. CNTs may also be examined when the growth layers are very thin, and even when only a few nanotubes are on a substrate. Replicas can be taken from various substrate shapes covered with nanostructures and from minute or specifically selected areas of the substrates. CNTs extracted by the replica are not disturbed, and their nanostructures are preserved. It is demonstrated that using positive replicas, HRTEM images from the nanosized carbon forms can also be obtained.