Kinetic analysis of respiratory tract proteins recovered during a sequential lavage protocol

Although bronchoalveolar lavage (BAL) has been used as a research tool for over a decade, the technique of lavage has varied markedly between laboratories. For example, lavage instillate volumes from 50 to 300 ml have been used, and yet the influence of the variable of total lavage volume on subsequent protein recovery is uncertain. We performed sequential BAL (50 ml/aliquot; total volume, 300 ml) of the right middle lobe of 14 normal volunteers and separately processed and analyzed recovered aliquots for the absolute and relative concentrations of several protein substances. These proteins include free secretory component and secretory IgA, which emanate from airway secretions, and IgG, which is thought to transude from more distal alveolar sites. Analysis of these data showed a marked decrease in the absolute concentration of all proteins measured in serial aliquots. Analysis of protein ratios in sequential aliquots, however, revealed no significant change from the first to the fifth recovered aliquot. Finally, we analyzed the influence of the size of the first recovered aliquot on absolute and relative concentrations of proteins. Here there seemed to be a trend indicating preferential recovery of airway proteins in smaller aliquots. This was significant for the ratio of free secretory component to albumin (p less than 0.05). We conclude that lung proteins are efficiently and homogeneously sampled with 100 ml of lavage instillate. Larger volumes will add more protein but not alter protein ratios. Lavage with smaller volumes may preferentially sample airway proteins.     

Selective listening asymmetry in preschool children.

42 right-handed preschoolers listened to dichotic presentations of digit names in 2 experimental sessions. Ss were told to report only the digit arriving at the designated ear; the target ear was designated prior to the dichotic presentation in one session (precuing condition) and after the presentation in the other session (postcuing condition). A significant right-ear superiority was found for all 3 dependent variables: number of correct identifications, total number of digits reported from each ear, and number of intrusion errors. Thus, the procedure demonstrated a marked asymmetry and, therefore, left lateralization of verbal processing in children as young as 3 yrs of age. Since the magnitude of asymmetry was as great in the precuing condition as in the postcuing condition, input factors (perceptual or attentional factors) are sufficient to account for the right-ear superiority. There was no age difference in degree of right-ear advantage. Correlations between asymmetry scores in the 2 sessions ranged between .60 and .68 for the 3 dependent variables. (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reaction of hexamethylene diisocyanate with poly(vinyl alcohol) films for biomedical applications

The objective of this work was to obtain primary amine groups on the surface of poly(vinyl alcohol) films by means of a reaction with hexamethylene diisocyanate. The reaction was run in such a way as to minimize the internal crosslinking by employing a large excess of hexamethylene diisocyanate in toluene and then hydrolyzing the unreacted isocyanate endgroup to primary amine. After dialyzing out the adsorbed hexamethylenediamine from the aqueous solution of reacted poly(vinyl alcohol), the extent of covalent bonding of hexamethylene diisocyanate onto the polymer was determined by measuring aminohexyl content through a fluorescence assay. This assay is based on the reaction of fluorescamine, 4-phenylspiro[furan-2(3H)-1′-phthalan]-3,3′-dione, with a primary amine to yield a fluorophor which will emit a strong fluorescence at 475–490 nm when excited at 390 nm. Analyses show a range of 1.1 × 10^?10?3.6 × 10^?10 mole of amines per cm² of reacted poly(vinyl alcohol) film. When assuming 47% as degree of crystallinity approximated by IR spectroscopy for these polymer films, the availability of hydroxyl groups in amorphous region was estimated to be 3.7 × 10^?10 mole/cm². The extent of reaction based on available hydroxyl groups was then in the range of 31–97%. The primary amine groups attached by this method can now be exploited for binding biomolecules such as heparin (anticoagulant) or fibrinolytic enzymes in an attempt to achieve biocompatible materials.     

Differential scanning calorimetry of crystallized PVA hydrogels

Crosslinked poly(vinyl alcohol) hydrogels produced via electron beam irradiation of aqueous PVA solutions were crystallized via a two-stage dehydration-annealing process to produce swollen hydrogels of varying degrees of crystallinity. Evaluation of the degree of crystallinity of these hydrogels was done by differential scanning calorimetry (DSC) analysis. The swollen hydrogels had degrees of crystallinities varying between 30% and 50% depending on the temperature–time history of the specimens.     

Content Analysis—A Probabilistic Approach

A probabilistic model is presented which may be applied to perform content analysis on the computer. The procedure employs word stems as category entries and probabilities rather than units for allocating and enumerating content among categories. An application of the model was made to compare content coverage in monopoly and competitive newspapers. There was no appreciable difference due to interaction among monopoly and competitive paper types and content categories. Comparisons among categories showed an appreciably greater probability of news of more‘everyday’than of a violent classification, a finding which challenges a common criticism that the press presents disproportionate content of an inflammatory or violent nature.