Ciprofloxacin increases hepatic and renal lipid hydroperoxides levels in mice

Ciprofloxacin (CFX) is an effective and relatively safe antimicrobial used in a variety of human infections. However, adverse drug reactions and positive results in genotoxic tests are reported.
In order to understand the possible pathophysiological mechanisms of the toxic effects informed for CFX, lipid hydroperoxides (LOOH) -oxidative mediators of peroxidation- were quantified in liver and kidney of mice, after 15 to 360 minutes of the ciprofloxacin administration at doses of 10 mg/ Kg or 100 mg/ Kg by ip route. The peroxidation in the lipid fraction was evaluated by measuring the amount of hydroperoxides through the oxidation of 1- naphthyldiphenylphospine into its oxide and further quantification by high performance liquid chromatography.
The initial content of lipid hydroperoxides (nmol/g tissue) was 253 ± 3 in kidney and 143 ± 12 in liver. CFX induced the maximal variation to 728 ± 101 in kidney (P < 0.05) and 315 ± 31 in liver (P < 0.01), after 15 min of 100 mg/ Kg single dose. The variation in the LOOH levels was significant in kidney with both doses used and in liver after 100 mg/ Kg until 60 min after the CFX administration, and then gradually fell to natural levels.
The results demonstrated the effect of CFX on lipid oxidation, an indicator of oxidative effect. A natural protective capacity against this oxidation, more efficient in liver than in kidney, was observed.     

CHANGES IN PROTEIN COMPOSITION DURING STRAWBERRY (Fragaria × ananassa Duch.) FRUIT RIPENING1

The changes in strawberry native proteins and polypeptides during ripening were studied. Analysis of protein extracts by nondenaturing electrophoresis showed the presence of a protein species only in the ‘25% Red’ and later ripening stage. This 40 kD polypeptide was hardly detected in ‘Large green’ and ‘White’ fruit extracts. The polypeptide profile, obtained with SDS-PAGE, also changed during ripening. While most polypeptides were found in all ripening stages, the distribution of some of them varied during ripening. Protein synthesis (measured by ³⁵ S-methionine labelling) in strawberry was mainly directed towards the regeneration of previously existing proteins. As ripening proceeded, the synthesis of 67 and 63 kD polypeptides increased, while those of 82, 56 and 25 kD decreased. Three very-abundant polypeptides (36, 24 and 23 kD) were located in the achenes and were not labelled in any ripening stage.     

Distribution of NADPH-diaphorase in rat mesencephalon: A light and electron microscopical study

NADPH-diaphorase is a useful technique to reveal NO producing neurons at light microscopic level (LM). A modification of the technique using the tetrazolium salt BSPT as susbtrate, is useful to study the ultrastructure of NO neurons. The aim of this work was to perform a detailed analysis of NADPH diaphorase reactive neurons in rat mesencephalon both at light and electron microscopic levels.
NADPH-diaphorase reactive neurons were observed in superior colliculus, in central gray matter, in dorsal and medial raphe and in the pedunculopontine tegmental nucleus using two histochemical techniques at LM. Electron microscopy showed deposits on membranes of the endoplasmic reticulum, Golgi apparatus and nuclear envelope of dorsal raphe neurons. Presynaptic and postsynaptic terminals showed deposits on membranous elements but postsynaptic terminals also showed deposits on the inner surface of their membranes.
Further physiological studies are needed to clarify the meaning of the ultrastructural findings such as the putative interaction of NOS with postsynaptic proteins, receptors or membranous channels.     

A unique mechanism of nuclear division in <i>Giardia lamblia</i> involves components of the ventral disk and the nuclear envelope

The fine structure of the binucleate, parasitic protist Giardia lamblia during interphase and divisional stages was studied by serial thin sectioning and three-dimensional reconstructions. The earlier sign of nuclear division is the development of a few peripheral areas of densely packed chromatin directly attached to the inner nuclear envelope. An intracytoplasmic sheet of ventral disk components grows from the cell periphery towards one of the nuclei, apparently constricting this nucleus, which becomes located at a ventral bulge. After the basal bodies become duplicated, a full nuclear division occurs in trophozoites, giving two pairs of parent-daughter nuclei. This full division occurs in a dorsal-ventral direction, with the resulting nuclear pairs located at the sides of the two sets of basal bodies. A new ventral disk is formed from the diskderived sheets in the cell harboring the four nuclei. Cytokinesis is polymorphic, but at early stages is dorsalto-dorsal. Encysting trophozoites show the development of Golgi cisternae stacks and dense, specific secretory granules. 3-D reconstructions show that cysts contain a single pair of incompletely strangled nuclei. The dividing Giardia lacks a typical, microtubular spindle either inside or outside the nuclei. The nuclear envelope seems to be the only structure involved in the final division of the parent-daughter nuclei.     

Determination of OH Extinction Coefficients in R2O-B2O3-SiO2 Glasses (R = Li, Na, K)

Infrared spectra of glasses of the system R₂O-B₂O₃-SiO₂ were investigated. The extinction coefficients of the hydroxyl absorption band ("free OH") were calculated by a method proposed for alkali borate glasses. The results confirmed the applicability of this method to homogeneous and phase-separated alkali borosilicate glasses. The variation of the hydroxyl absorption band position was interpreted according to the structural characteristics of the studied glasses.