Stycholysin II, a cytolysin from the sea anemone Stichodactyla helianthus promotes higher hemolysis in aged red blood cells

We have investigated the relationship between the status of red blood cells (RBCs) and their susceptibility to toxin sticholysin II (StII) hemolytic activity; we have evaluated this effect in different RBC ensembles, comprising young and old cells, and in cells partially damaged by their pre-exposition to a free radical source. Upon action of StII, young cell populations are less prone to hemolysis than the whole population, while old cell populations and peroxyl-oxidized red cells are lysed faster than the whole population. Cell K(+) content was higher in young cells and lower in both senescent cells and in peroxyl-damaged cells relative to whole cell population. The relevance of cell K(+) content in St II-induced lysis was shown when external Na(+) was partially replaced by K(+); under this condition, RBC lysed faster in the presence of St II but no difference was observed among young cells, whole cells population and peroxyl-damaged cells; only old cells lysed faster that the whole population, response that can be due to an enhanced St II-induced pore formation as supported by evaluation of St II irreversible binding to RBC. It is concluded that this factor and the amount of intracellular K(+) are the dominant parameters that modulate the resistance of RBC to St II-induced lysis.

Headspace solid-phase microextraction of higher fatty acid ethyl esters in white rum aroma

Fatty acid ethyl esters are the main components of rum aroma and play an important sensorial impact in these distilled alcoholic beverages. Herein, a method for analysing these volatile compounds is described. It involves a separation and concentration step using headspace solid-phase microextraction and determination by capillary gas chromatography using flame ionisation detection. The influence of different parameters related to the isolation and concentration step, such as ethanol concentration, ionic strength, sample volume, time and temperature of extraction, was studied. The developed method enabled recoveries >91% for the analyzed compounds with limits of detection between 0.007 and 0.027 mg/l, all of them lower than the range of concentrations found in rum samples. The method was successfully applied to the analysis of fatty acid ethyl esters in different commercial white rums.

Classification of ancient Roman glazed ceramics using the neural network of Self-Organizing Maps

Artificial neural networks with unsupervised learning strategy known as Self-Organizing Maps were applied to classify ancient Roman glazed ceramics. Their clay ceramic bodies were analyzed by Inductively Coupled Plasma-Atomic Emission Spectroscopy and the chemical composition obtained was processed by this neural algorithm. The results obtained provide two types of information: firstly, classification of ceramic samples with identification of several groups and secondly, differentiation between the elemental chemical information. It was found that there are certain chemical elements which can be considered as principal and which can serve to differentiate between ceramics, whereas other elements give redundant information and do not contribute to sample differentiation. Seven chemical elements were considered principal and provide the necessary information. Two types of element were identified: 1- a group formed by common elements, such as: Ca, Fe, Mg, Mn and 2- another formed by optional elements: K or Na and Ba or Sr and Al or Ti.

Experimental flail chest: ventilatory function with fixation of flail segment in internal and external position

The effect on ventilatory function of fixation of a flail segment in internal (FIP) and external (FEP) position and oxygen administration was studied in an experimental flail chest with pleural indemnity. Variations of tidal volume (TV), respiratory rate (RR), minute volume (MV), and arterial blood gases are reported. These parameters were measured in nine dogs in control and flail conditions (FC). The effect of FIP, FEP, and oxygen administration were studied.

RESULTS

Significant differences were found: TV decreased from control values to FC and from FC to FIP, but increased from FC to FEP. RR values increased from control to FC and from FC to FIP, but decreased from FC to FEP. MV values decreased from FC to FEP. TV, RR, and MV were not changed under oxygen administration. Hypoxemia or hypercapnia were not observed. It was concluded that FIP is deleterious for respiratory mechanics, whereas FEP improves ventilatory parameters.

[Fatigue resistance of inspiratory muscles in patients with severe mitral valve stenosis]

The strength and endurance of the inspiratory muscles was assessed in 14 patients with severe mitral valve stenosis uncomplicated by other diseases. Strength was evaluated measuring the maximal static inspiratory pressure (MIP). Endurance was measured using a two minute weight incremental test, to obtain the maximal sustainable pressure (SIP), which is the highest pressure that a subject can generate to mobilize air with incremental weight during inspiration. MIP was similar to that of 8 normal subjects (110 +/- 21 and 128 +/- 27 cm H2O respectively p = NS). SIP, maximal sustainable weight and SIP as percentage of MIP were 47 +/- 10 cm H2O, 261 +/- 81 g and 43 +/- 6% respectively, all lower than in normal subjects (89 +/- 25 cm H2O, 525 +/- 167 g and 71 +/- 15% respectively) We conclude that patients with severe mitral valve stenosis have decreased inspiratory muscle endurance compared to normal subjects and this feature may be related to their decreased exercise tolerance.

[Volume, flow and respiratory muscle strength in mitral stenosis]

Pulmonary function and respiratory muscle strength was assessed in 20 patients with mitral stenosis uncomplicated by other illness. Pulmonary function was evaluated by spirometry, flow-volume curves, functional residual capacity (FRC) and total lung capacity (TLC). Respiratory muscle strength was evaluated by measurement of maximal static inspiratory and expiratory mouth pressure (PIM, PEM cmH2O) at FRC and TLC respectively. Spirometric, FRC and TLC average values were normal. The maximal expiratory flow rate at 50 and 25% of vital capacity were decreased to 49.5 and 38.3% from predicted values. The values of PIM and PEM in patients (-93 +/- 17; 128 +/- 32 cmH2O, respectively) were similar to those of 12 normal subjects studied at comparable lung volume. Our results were similar to previous reports. There was no evidence of decreased respiratory muscle force, probably because the patients nutritional status and cardiac output were normal.