Representing primary electrophoretic data in the 1/time domain: comparison to representations in the time domain

A plot of absorbance vs 1/time (the "1/time domain") is a more useful representation of the primary data in capillary electrophoresis than traditional plots of absorbance vs time (the "time domain") in a wide set of circumstances, especially when comparing electropherograms in which the rate of electroosmotic flow is not precisely the same. The quantity that is of fundamental interest in capillary electrophoresis (CE) is the electrophoretic mobility of an analyte. The electrophoretic mobility of a species is nonlinearly proportional to time and, therefore, not linearly represented in the time domain: that is, the distance between two peaks along the time axis is not linearly related to the difference in their electrophoretic mobilities. In contrast, the electrophoretic mobility is linearly proportional to 1/time, and the distance between two peaks along the 1/time axis is linearly related to the difference in electrophoretic mobilities. Plots in the 1/time domain are similar to the familiar plots in the time domain (each analyte is represented by a peak, and the order of peaks corresponds to the order in which these analytes reach the detector), but the spacing between the peaks corresponds linearly to differences in mobility. This article derives this useful, visually appealing, and broadly applicable plotting strategy and illustrates common situations in which these plots are more useful than plots in the time domain.     

Prognostic relevance of urokinase plasminogen activator detection in micrometastatic cells in the bone marrow of patients with primary breast cancer

The "attentional model" of time estimation assumes that temporal judgments depend on the amount of attention allocated to the temporal processor (the timer). One of the main predictions of this model is that an interval will be judged shorter when attention is not allocated to the temporal parameters of the task. Previous studies combining temporal and nontemporal tasks (dual-task method) have suggested that the time spent processing the target duration might be a key factor. The less time devoted by the subject to the temporal task, the shorter the judged duration. In the two experiments presented here, subjects were asked to judge both the duration of a visual stimulus and an increment in intensity occurring at any time during this stimulus. In the second experiment, trials without intensity increments were added. The main result is that the judged duration was shorter when the increment occurred later in the stimulus or did not occur. In those cases, subjects had been expecting increment occurrence during most part of the stimulus and thus had focused for a shorter time on stimulus duration. We propose that attention shifts related to expectancy and to detection of the increment reduce subjective duration.     

Behavior and behavioral needs

An understanding of behavior is important in any consideration of poultry welfare. Behavior is a good indicator of states of suffering such as fear, frustration, and pain. It might also be possible to use social interactions as indicators of welfare. The possibility of using "luxury" behavior, such as play and exploratory behavior, as an indicator of positive emotional states, requires investigation. Important welfare consequences arise from the fact that some behavior may be so strongly motivated as to constitute a "need". A behavioral need will arise in the case of behavior, such as nesting, that is controlled largely by internal factors, because these factors will be present no matter what type of environment is provided. Behavior triggered largely by external stimuli, such as responses to predators, will not give rise to a need if the external factors can be removed from the environment. Dustbathing is an example of behavior controlled by complex interactions between internal and external factors; the extent to which this constitutes a need is still being debated. If a behavioral need arises, then it is important that the environment provided allows it to be performed without damage to the performer or other birds. It should also be remembered that birds may need to perform behavior, including appetitive as well as consummatory elements, although the functional consequences of these are no longer required for survival. Finally, the performance of certain behavior leads to an increase in health or physical condition that improves welfare later in life.     

Seasonal changes in the negative feedback regulation of the secretion of the gonadotrophins by testosterone and inhibin in rams

Three experiments were conducted with castrated Romney Marsh rams (wethers) to investigate the ability of testosterone and inhibin to suppress the secretion of LH and FSH during the breeding and the non-breeding seasons. In Experiment 1, wethers (n=5/group) were treated every 12 h for 7 days with oil or 16 mg testosterone propionate (i.m.) and were then given two i.v. injections either of vehicle or of 0.64 microg/kg human recombinant inhibin A (hr-inhibin) 6 h apart. Blood samples were collected for 4 h before inhibin or vehicle treatment and for 6 h afterwards for the assay of LH and FSH. In Experiments 2 and 3 wethers underwent hypothalamo-pituitary disconnection (HPD) and were given 125 ng GnRH i.v. every 2 h. In Experiment 2, HPD wethers (n=3/group) were injected (i.m.) every 12 h with oil or testosterone and blood samples were collected over 9 h before treatment and 7 days after treatment. In Experiment 3, HPD (n=5/group) wethers were treated with vehicle or hr-inhibin, as in Experiment 1, after treatment with oil, or 4, 8 or 16 mg testosterone twice daily for 7 days. Blood samples were collected over 4 h before treatment with vehicle or hr-inhibin and for 6 h afterwards. Treatment of wethers with testosterone (Experiment 1) resulted in a significant decrease in the plasma concentrations of LH and number of LH pulses per hour but the magnitude of these reductions did not differ between seasons. Testosterone treatment had no effect on LH secretion in GnRH-pulsed HPD wethers in either season and treatment with hr-inhibin did not affect LH secretion in wethers or HPD wethers in any instance. Plasma concentrations of FSH were significantly (P<0.05) reduced following treatment with testosterone alone during the breeding season but not during the non-breeding season. FSH levels were reduced to a greater extent by treatment with hr-inhibin but this effect was not influenced by season. During the non-breeding season, the effect of hr-inhibin to suppress FSH secretion was enhanced in the presence of testosterone. These experiments demonstrate that the negative feedback actions of testosterone on the secretion of LH in this breed of rams occurs at the hypothalamic level and is not influenced by season. In contrast, both testosterone and inhibin act on the pituitary gland to suppress the secretion of FSH and these responses are affected by season. Testosterone and inhibin synergize at the pituitary to regulate FSH secretion during the non-breeding season but not during the breeding season.     

An investigation into factors affecting proteocine production by Proteus isolates

Proteocine production was found to the influenced by the medium used, the temperature of incubation and the length of incubation. Different amounts of proteocine were produced in different media. Production in liquid media was maximum in proteose-peptone No. 3 (Difco). This medium gave a very high titre (1:10000) of proteocine when inoculated with the producer strain, and the aerated culture was induced with mitomycin C. Therefore a method of producing a high titre proteocine was developed using proteosepeptone No. 3 (Difco) and cultural conditions of 25 degrees C for 24 hours.     

A comparison of the effect of two regimens of infestation on the development of resistance by cattle to the cattle tick, Boophilus microplus (Can.)

The development of resistance to Boophilus microplus by cattle was studied using sets of cattle twins, in stalls. One twin from each set received 3 infestations of 40,000 larvae and the other a continuous infestation of 1,000 larvae a day over the same period. Sets of twins were then challenged with 1,000 larvae a day for 40 days and 2 field infestations of 20,000 larvae. Correlations of ranking for resistance made at 40-day periods during daily infestations of 1,000 larval ticks or for corresponding intermittent infestations of 40,000 larvae were low until animals had received 120,000 larvae. Thereafter irrespective of method of infestation correlations of ranking were relatively high (r = 0.61-0.96) between periods of infestations or method of infestation including 2 field infestations. Fewer adult female ticks matured on the daily infested animals than on the intermittently infested animals during the treatment period, but animals developed a similar resistance level whether infested with either technique.     

Monomeric, monovalent derivative of Maackia amurensis leukoagglutinin. Preparation and application to the study of cell surface glycoconjugates by flow cytometry

A stable subunit of Maackia amurensis leukoagglutinin (MMAL) was prepared by the selective reduction of disulfide bridges between the subunits followed by alkylation with 4-vinylpyridine. MMAL failed to precipitate fetuin, whereas it retained its ability to bind to the same glycoprotein coated on a plastic plate, indicating the monovalency of this derivative. This binding to immobilized fetuin was inhibited by a haptenic sugar, Neu5Ac alpha 2-3lactose, with the same inhibitory potency as against the native M. amurensis leukoagglutinin. Microscopic observation as well as flow cytometric analyses showed that Chinese hamster ovary cells were clearly stained with fluorescein isothiocyanate-labeled MMAL without any detectable agglutination. This staining was inhibited by the addition of fetuin or by the sugar chains of fetuin. Differences in the types of sialylated glycoconjugates on the cell surface of several cell lines were detected by the combined use of fluorescein isothiocyanate-labeled MMAL and the monomeric derivative of elderberry bark lectin (specific for the Neu5Ac alpha 2-6Gal/GalNAc sequence) by flow cytometry. These results demonstrate the usefulness of these monovalent derivatives of sialylated oligosaccharide-specific lectins as probes for the analysis of cell surface glycoconjugates containing sialic acid by the technique of flow cytometry.     

NO- and NO2-carrying molecules potentiate photorelaxation in rat trachea and aorta

Photorelaxation elicited by ultraviolet light (366 nm) was investigated on isolated rat thoracic aorta and trachealis. Rat tracheal smooth muscle but not aorta did not show UV-induced photorelaxation. Both streptozotocin, NO-carrying molecule and N omega-nitro-L-arginine, NO2-carrying molecule significantly enhanced photorelaxation, concentration-dependently, in rat trachealis and aorta. Methylene blue (10 microM) inhibited the potentiation action of streptozotocin and N omega-nitro-L-arginine in both tissues. Superoxide dismutase (300 U/ml) enhanced streptozotocin- and N omega-nitro-L-arginine-potentiated photorelaxation in rat trachealis, while pyrogallol (0.1 mM), a potent O2- generating agent, inhibited streptozotocin-potentiated photorelaxation in trachealis. Streptozotocin was much more effective than N omega-nitro-L-Arginine in potentiating of photorelaxation elicited by UV light in both tissues. From these findings, we conclude that streptozotocin and N omega-nitro-L-arginine produce EDRF like labile substance(s) by UV irradiation.     

Computerized analysis of isometric tension studies provides important additional information about vasomotor activity

Concentration-response curves of isometric tension studies on isolated blood vessels are obtained traditionally. Although parameters such as Imax, EC50 and pA2 may be readily calculated, this method does not provide information on the temporal profile of the responses or the actual nature of the reaction curves. Computerized data acquisition systems can be used to obtain average data that represent a new source of otherwise inaccessible information, since early and late responses may be observed separately in detail.