For many years, clinical and non-clinical investigations have investigated cortical bone structure in an attempt to address questions related to normal bone development, mineralisation, pathologies and even evolutionary trends in our lineage (adaptations). Research in the fields of medicine, materials science, physical anthropology, palaeontology, and even archaeobiology has contributed interesting data. However, many questions remain regarding the histomorphological and histochemical variations in human cortical bone during different stages of life. In the present work, we describe a study of long bone cortex transformations during ontogeny. We analysed cross-sections of 15 human humeri histomorphologically and histochemically from perinatal to adult age, marking and quantifying the spatial distribution of bone tissue types using GIS software and analysing the mineral composition and crystallinity of the mineralised cortex using Raman spectroscopy and X-ray diffraction. Our results allowed us to propose that human cortical bone undergoes three main 'events' through ontogeny that critically change the proportions and structure of the cortex. In early development, bone is not well mineralised and proportionally presents a wide cortex that narrows through the end of childhood. Before reaching complete maturity, the bone mineral area increases, allowing the bone to nearly reach the adult size. The medullary cavity is reduced, and the mineral areas have a highly ordered crystalline structure. The last event occurs in adulthood, when the 'oldest' individuals present a reduced mineralised area, with increasing non-mineralised cavities (including the medullary cavity) and reduced crystalline organisation.

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Experimental evidence suggests that release of neurotransmitters in response to acute noxious stimulation and inflammation can differ in superficial and deeper dorsal horn (DH) laminae. Using two different microdialysis probes, we studied changes in levels of glutamate, aspartate, arginine and GABA in dialysates collected from the surface of the spinal cord and within the DH induced by pinching the paw or paw inflammation. In penthotal anaesthetized rats, a flexible microdialysis probe was placed on the dorsal surface of the L4-L5 or L6-S2 spinal segments. In other rats, a rigid microdialysis probe was implanted within the DH of the same segments. Samples were collected every minute before, during and after pinching the hind paw (acute pain), and every half an hour after injecting either carrageenan or saline into the same paw (inflammation-induced pain). Amino acids were measured by capillary zone electrophoresis with laser-induced fluorescence detection (CZE-LIFD). Pinching the paw induced a significant but short lasting increase in extracellular glutamate and aspartate in dialysates from the surface of the DH. Carrageenan, but not saline, injected into the paw significantly increased concentrations of glutamate, aspartate and arginine both on the surface and within the DH of L4-L5 and also within the DH of the L6-S2 segments. The GABA level was significantly increased following carrageenan only within the DH. The maximum increase on the surface was detected 60-120 min after the onset of inflammation whereas the response within the DH reached a maximum between 150 and 180 min after carrageenan. These results indicate that unlike acute mechanical noxious stimulation which enhances amino acid neurotransmitters in surface dialysate, inflammation induced neurotransmitter release in all layers of the DH suggesting sensitization of the DH.

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The detection and determination of s-triazines, atrazine-desethyl and aziprotryne by cyclic voltammetry and an amperometric method using a metallic copper electrode and a glassy carbon electrode are described. The concentrations of atrazine-desethyl and aziprotryne in 0.1 M NaOH solutions were determined using the oxidation signal corresponding to the Cu(0)/Cu(I) redox process. The detection level calculated for these s-triazines were 0.3 and 0.5 microg/mL of analyte, respectively. The glassy carbon electrode was shown to give sensitive reduction response to aziprotryne in flow injection mode. No special activation was required for the glassy carbon electrode. A detection limit of 0.2 microg/mL (20 ng aziprotryne) was obtained for a sample loop of 0.1 mL at a fixed potential of -1.0 V (vs. Ag/AgCl) in 0.1 M HCl and a flow rate of 3.5 mL/min. Furthermore, the glassy carbon electrode showed stable response in such a system, and the relative standard deviation was only 2.7% using the same surface, and 6.3% using different surfaces. The method developed was applied to the determination of aziprotryne in environmental and tap water samples; using a prior solid-phase extraction step, aziprotryne concentrations lower than 1.0 ng/mL could be measured.