Brillouin and Raman Micro-Spectroscopy: A Tool for Micro-Mechanical and Structural Characterization of Cortical and Trabecular Bone Tissues

Human bone is a specialized tissue with unique material properties, providing mechanical support and resistance to the skeleton and simultaneously assuring capability of adaptation and remodelling. Knowing the properties of such a structure down to the micro-scale is of utmost importance, not only for the design of effective biomimetic materials but also to be able to detect pathological alterations in material properties, such as micro-fractures or abnormal tissue remodelling. The Brillouin and Raman micro-spectroscopic (BRmS) approach has the potential to become a first-choice technique, as it is capable of simultaneously investigating samples’ mechanical and structural properties in a non-destructive and label-free way. Here, we perform a mapping of cortical and trabecular bone sections of a femoral epiphysis, demonstrating the capability of the technique for discovering the morpho-mechanics of cells, the extracellular matrix, and marrow constituents. Moreover, the interpretation of Brillouin and Raman spectra merged with an approach of data mining is used to compare the mechanical alterations in specimens excised from distinct anatomical areas and subjected to different sample processing. The results disclose in both cases specific alterations in the morphology and/or in the tissue chemical make-up, which strongly affects bone mechanical properties, providing a method potentially extendable to other important biomedical issues.     

Retrospective evaluation of DNA ploidy of hepatocarcinoma on cytologic samples

DNA ploidy was evaluated by image cytometry in a series of 84 hepatocellular carcinomas diagnosed by fine-needle aspiration biopsy. In the series were included eight cases originally diagnosed as suspect and reclassified as well-differentiated hepatocarcinoma. The study was retrospectively performed on Papanicolaou-destained, Feulgen-restained smears. The 5c exceeding rate and the visual interpretation of the corresponding histograms were evaluated and compared with size of the tumors, serum α-fetoprotein values, hepatic functional staging, and patient survival. Sixty-eight cases were aneuploid and 16 euploid (9 diploid and 7 polyploid). Four of the eight cytologically suspect cases were aneuploid. Statistical analysis showed an association between size and cytologic grading, 5c exceeding rate and cytologic grading, and between aneuploidy and multiple tumors; in a Cox multivariate DNA content analysis, aneuploidy and multiple tumors were the two prognostically significant variables. DNA ploidy evaluation by static cytometry of hepatic tumors may be useful in the diagnosis on cytologic samples and could represent an independent prognostic parameter in predicting the survival outcome of patients with hepatocellular carcinoma. Diagn. Cytopathol. 1998;19:323–329. © 1998 Wiley-Liss, Inc.     

Constitutive expression of β-N-acetylhexosaminidase in a microglial cell line: Transcriptional modulation by lipopolysaccharide and serum factors

We investigated the expression of the α- and β-subunits of the lysosomal enzyme β-N-acetylhexosaminidase in the BV-2 microglial cell line under different culture conditions. β-N-acetylhexosaminidase from BV-2 microglia cells was separated into its constituent isoenzymes on diethylaminoethyl (DEAE) cellulose, and its activity was monitored with 4-methylumbelliferyl-β-N-acetylglucosamine and 4-methylumbelliferyl-β-N-acetylglucosamine-6-sulphate substrates. Forms corresponding to the mouse isoenzymes A and B were present in the cells incubated in serum-supplemented medium as well as in serum-free medium. Lipopolysaccharide, a well-known activator of microglia in vitro, added to the BV-2 cells in serum-supplemented medium induced a decrease in the specific enzymatic activity determined with the 4-methylumbelliferyl-β-N-acetylglucosamine substrate. Lipopolysaccharide had no effect on hexosaminidase isoenzyme pattern of BV-2 cells in serum-supplemented medium. The level of α-subunit mRNA was increased and the level of β-subunit mRNA was decreased in BV-2 cells incubated in serum-supplemented medium plus lipopolysaccharide. In the cells incubated in a serum-free medium no significant changes in the hexosaminidase-specific activities towards the above substrates were observed. Interestingly, increased expression of α- and β-subunit mRNA was evident in comparison with cultures in serum-supplemented medium. The present results suggest that the BV-2 cell line may be a useful tool to study the possible role of microglia in the metabolism of brain glycolipids. J. Neurosci. Res. 50:44–49, 1997. © 1997 Wiley-Liss, Inc.     

Synthesis and pharmacological properties of 5H,10H‐imidazo[1,2‐a]indeno[1,2‐e]pyrazine‐4‐one,a new competitive AMPA/KA receptor antagonist

The excessive release of glutamate, a potent excitatory neurotransmitter, is thought to play an important role in a variety of acute and chronic neurological disorders. Consequently, excitatory amino acid antagonists may have an important therapeutic potential in the treatment of these diseases. Glutamate interacts with at least three types of receptor: 1) NMDA (N‐methyl‐D‐aspartic acid) receptors; 2) AMPA [2‐amino‐3‐(3‐hydroxy‐5‐methylisoxazol‐4‐yl)propionic acid]/kainic acid (KA) receptors; and 3) metabotropic receptors. Blockade of ionotropic AMPA/KA receptors has been shown to prevent cerebral ischemia insult in experimental models. This article describes the synthesis, pharmacological activity, and neuroprotective properties of 5H,10H‐imidazo[1,2‐a]indeno[1,2‐e]pyrazine‐4‐one ( 1 ), a novel AMPA/KA antagonist which showed micromolar affinity at AMPA/KA receptors and competitively inhibited functional responses mediated by these receptors. In mice, 1 had significant anticonvulsive properties and conferred protection against hypobaric hypoxia and KCN intoxication. In rats and gerbils, 1 possesses significant activity in models of global or focal cerebral ischemia, as well as in a model of neurotrauma. Compound 1 was prepared from 2‐bromo‐indanone using two synthetic pathways in two or three steps with moderate (30%) or good (70%) yields, respectively. Drug Dev. Res. 48:121–129, 1999. © 1999 Wiley‐Liss, Inc.