Martin Kopáni

Salivary thiobarbituric acid reacting substances and malondialdehyde - Their relationship to reported smoking and to parodontal status described by the papillary bleeding index

Background. Thiobarbituric reacting substances (TBARS) are markers of lipoperoxidation. The best-known specific TBARS is malondialdehyde (MDA). Results from our previous studies have shown that TBARS can be measured in saliva and are increased in patients with gingivitis. Whether MDA is the main TBARS in saliva from patients with altered parodontal status is unknown. Aim. To observe the relationship between the parodontal status and TBARS, MDA and the number of epithelial cells in saliva. Subjects & Methods. In Study I saliva and plasma samples of 15 patients (8F, 7M) suffering from inflammatory periodontal diseases were gathered and TBARS levels were measured in these samples. In Study II saliva samples from 217 consecutive stomatologic patients were collected and analysed for TBARS spectrofluorometrically, MDA by high-performance liquid chromatography and epithelial cell count by light microscopy. Papillary bleeding index (PBI) was determined in standard stomatologic examination. Results. In Study I results from our previous studies showing no correlation between salivary and plasma TBARS levels were confirmed. This indicates that the local salivary level of TBARS is unlikely to be directly affected by systemic oxidative stress. In Study II higher PBI was associated independently (adjusted for age and sex) tightly with higher TBARS (p < 0.001) and with lower number of epithelial cells in saliva (p < 0.05). Smokers had higher salivary MDA levels (p < 0.003) and lower number of epithelial cells in saliva (p < 0.01). Conclusion. Salivary TBARS are a simple parameter that partially reflects the parodontal status with a potential usefulness in the clinical stomatology. We show herein that salivary MDA is dependent on age and smoking, but there is no correlation between MDA and PBI. Further studies should uncover the main salivary TBARS compound in patients with altered parodontal status and trace the origin of these salivary lipoperoxidation markers.

Iron in spleen tissues

This contribution aims in characterization of structural positions of iron in human and horse spleen. 57Fe Mossbauer spectroscopy was employed as a principal method of investigation in addition to X-ray diffraction and transmission electron microscopy (TEM). At room temperature, ferritin nanoparticles exhibit superparamagnetic behavior due to their small dimensions. Corresponding Mossbauer spectra show doublet-like patterns. Experiments performed at low temperatures unveiled presence of magnetically split components and enabled to determine the blocking temperature. Dimensions of Fe-containing species were established from detailed analyses of TEM images.

Influence of vitamin C on alcohol binding to phospholipid monolayers

The simple model of the biological membrane is provided by well-controlled lipid monolayers at the air–water interface. The Maxwell displacement current technique (MDC) provides novel approach to conformation study of the membrane models. The effect of alcohols is interaction with membrane molecules, mainly with the lipid head group and consequent changes in physical–chemical properties of the membrane. The aim of study is to detect changes in structural, electrical and mechanical properties of dipalmitoyl-phosphatidylcholine (DPPC) monolayer on the subphase of methanol–water and ethanol–water mixtures before and after addition of antioxidant agent, vitamin C. Monolayers properties are investigated by a surface pressure analysis (including mechanical properties evaluation) and the Maxwell displacement current measurement, the dipole moment projection calculation. Surface pressure–area isotherms show similar behaviour of the DPPC monolayer on alcohol–water mixtures independently on presence of vitamin C. Binding/adsorption process induces change of electron density distribution across monolayer and thus the molecular dipole moment. We observe small or negligible binding of methanol molecules on oxygen bonds of DPPC. Thus the antioxidant, vitamin C, has no significant effect. For ethanol–water mixtures is observed recovery of electrical properties in presence of antioxidant agent. We suppose that vitamin C regulates DPPC–ethanol molecules interaction.

The Effect of Salivary Gland Extract of Lucilia sericata Maggots on Human Dermal Fibroblast Proliferation within Collagen/Hyaluronan Membrane In Vitro: Transmission Electron Microscopy Study

BACKGROUND: Lucilia sericata maggots are applied to chronic wounds to aid healing when conventional treatments have failed. After their application into a necrotic wound, they potentially influence wound healing with a combination of specific proteinases that are involved in the remodeling of extracellular matrix. These proteases cause changes in fibroblast adhesion and spread upon extracellular matrix protein surfaces, affecting integrity of the protein surfaces—especially fibronectin—while maintaining cell viability. OBJECTIVE: This study focused on in vitro monitoring of the effect of homogenate substances prepared from maggot salivary gland of L sericata on the ultrastructure of human neonatal fibroblasts. METHODS: Collagen/hyaluronan membrane was used as the synthetic substitute of extracellular matrix. The cultured human neonatal fibroblasts B–HNF-1 were seeded on the surface of the collagen/hyaluronan membrane and cultured with maggot salivary gland extract (SGE) at a concentration of 2.4 glands/1 mL. RESULTS: The authors observed increased cell metabolism and protein production (euchromatic nucleus, voluminous nuclear membrane, large reticular nuclei, distended and filled cisterns of rough endoplasmic reticulum, Golgi apparatus with saccules, and vesicles packed with fine fibrillar material) after incubating the cells in culture medium with SGE. CONCLUSION: The authors believe that increased cell metabolism and protein production corresponded with formation of microfibrillar net used for migration of fibroblasts in culture, but mainly for proper production of extracellular matrix. The authors suggest that their results may help explain the effect of SGE on wound healing and support implementation of maggot therapy into human medicine.

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.

Some possibilities of representing microcirculation in human spleen

The representation of microcirculation can be approached in several ways. One of the possibilities is to represent the endothelium (endothelial or sinus lining cells) and their basement membrane on the basis of detecting the known components and the expression of the surface antigenes by the methods of immuno-, enzyme- or lectino-histochemical analysis, or by staining or impregnation histological methods. The other possibility is the examination of samples by transmission and scanning electron microscopy. For three-dimensional demonstration corrosion casts techniques or laser scanning confocal microscopy can be used. In this paper we describe the survey of immuno-, enzyme- and lectino-histochemical characteristics of selected components of microcirculation and our own results of its demonstration in human spleen.

Magnetic Properties of Iron Oxides in the Human Globus pallidus

Several types of iron oxides can be found in the various parts of the human brain. These can be highlighted in the light microscopy and using scanning or transmission mode of the electron microscopy. Some of them are non-magnetic, some, on the contrary, display magnetic response. It is not clear which kind of magnetic particles are accumulated in the human brain as inorganic deposits. Light microscopy, electron microscopy and sensitive Superconducting Quantum Interference Device (SQUID magnetometer) were used in order to detect iron deposits and their magnetic response in the samples extracted from the Globus pallidus of the human brain. Electron microscopy reveals a presence of the single crystals of hematite (α-Fe2O3) of the size up to 1000 nm in the samples extracted from G. pallidus because of the diffractograms characteristic for the hexagonal unit cell; this mineral offers basically a diamagnetic response. The temperature dependence of the magnetic susceptibility allows a classification of the samples into three groups: mostly diamagnetic I, prevailing paramagnetic III, and an intermediate class II. The bulk samples exhibit a long-range magnetic ordering with magnetic hysteresis evidenced not only at low temperature but also at the room temperature. The recorded magnetic functions refer either to the presence of magnetite (Fe3O4), or maghemite (γ-Fe2O3). Iron oxides and oxidohydroxides found as inorganic deposits in the human brain can result from interaction between iron and microenvironment in the form of polysaccharides of glycoconjugates. They display magnetoactivity characteristic for magnetite and/or maghemite.

Mössbauer spectroscopy of Basal Ganglia

Chemical states, structural arrangement, and magnetic features of iron deposits in biological tissue of Basal Ganglia are characterized. The methods of SQUID magnetometry and electron microscopy are employed. 57Fe Mossbauer spectroscopy is used as a principal method of investigation. Though electron microscopy has unveiled robust crystals (1-3 μm in size) of iron oxides, they are not manifested in the corresponding 57Fe Mossbauer spectra. The latter were acquired at 300 K and 4.2 K and resemble ferritin-like behavior.

Analysis of Human Spleen Contamination

Introduction Besides carbon, oxygen and nitrogen, numerous other elements and their compounds are significant in the body of humans and other animals. Some elements get into the internal environment of living bodies, accumulate in various organs and disturb systems that participate in their elimination; or, on the contrary, they accumulate in the bodies because of congenital or acquired metabolic disturbances. Iron can be found in human body mainly in the form of ferritin. This protein creates spherical formation with the size of 12 nm. The core of ferritin is 8 nm big and consists of ferrihydride 5Fe2O3.9H2O. The role of polypeptide coat of ferritin (Ft-H form) is to catalyze Fe2+ ions to Fe3+ ions. Ft-H form of polypeptide coat helps to mineralization of iron. Studies performed via nanodiffraction showed that physiological ferritin is composed from crystalline ferrihydride and amorphous iron hydroxide [1]. In the core of pathological ferritin prevailed wüstite (FeO) and magnetite – like structure. In excessive volume of iron in the organism, the iron is stored in cells in the form of hemosiderin [2]. Hemosiderin is considered to be a proteolytic product of ferritin [3]. Besides the differences of diffraction image between the samples of hemosiderin it is found also some differences in their element composition [4,5]. The 57Fe Mössbauer spectroscopy enables to determine the composition of iron compound in the sample. Position, number and intensity of absorbed radiation give us information about chemical composition of the sample. Mössbauer spectra and their temperature dependence are characteristic for each iron compound. Biomimetic approach to material synthesis exhibits novel properties. Magnetic materials attract considerable interest both from biological point of view as well as their technological application [6].

Effect of HCN passivation on silicon oxide thin layer

Silicon dioxide layers are materials with unique dielectric and interface properties. We investigated samples with SiO2 layers prepared with nitric acid oxidation of silicon (NAOS) method and with natural oxide layer after passivation with HCN aqueous solution. Samples were investigated with atomic force microscopy (AFM) and Fourier transform infrared (FTIR) spectroscopy. We found higher roughness of layers after passivation and different effects of HCN passivation on samples. From the measurements, we conclude that HCN passivation influences structural and optical properties of SiO2 layer.