immunocytochemical localization of urokinase-type plasminogen activator in lewis lung carcinoma

The invasively growing and metasizing Lewis lung carcinoma consistently contained urokinase-type plasminogen activator (u-PA) enzyme activity. When investigated immunocytochemically with antibodies against u-PA, different parts of individual tumors showed a pronounced heterogeneity in staining intensity. Strong staining was found in areas with invasive growth and degradation of surrounding normal tissue, while other areas were completely devoid of staining. Immunoreactivity occurred both with a perinuclear cytoplasmic localization in tumor cells and associated with apparently extracellular material. SDS PAGE of tumor extracts, under both reducing and nonreducing conditions, followed by immunoblotting, showed only one immunocytochemically stainable band with an electrophoretic mobility corresponding to that of purified proenzyme to u-PA, while no two-chain u-PA was detected. This indicates that the major part of the activator in Lewis lung carcinoma is present as one-chain pro-u-PA.     

Perception by teenagers and adults of the changed by amplitude sound sequences used in models of movement of the sound source

The ability to evaluate direction of amplitude changes in sound stimuli was studied in adults and in the 11–12- and 15–16-year-old teenagers. The stimuli representing sequences of fragments of the tone of 1 kHz, whose amplitude is changing with time, are used as a model of approach and withdrawal of the sound source. The 11–12-year-old teenagers when estimating direction of amplitude changes were found to make significantly more errors than two other studied age groups, including those in repeated experiments. The structure of errors-the ratio of the portion of errors at estimation of increasing and decreasing by amplitude stimulus-turned out to differ in teenagers and in adults. There is discussed the problem of effect of unspecific activation of the large hemisphere cortex in teenagers on processes of taking solution about the complex sound stimulus, including the possibility of approach and withdrawal of the sound source.     

White Noise Masks Some Temporal Parameters of the Auditory Localization of Radially Moving Targets

The temporal parameters of the perception of radially moving sound sources partly masked with broadband internalized noise at an intensity of 40, 46, or 52 dB above the hearing threshold have been studied. The threshold of sound duration necessary for identifying the direction of movement of the sound source (75% correct answers) increases from 135 ms in silence to 285 ms at all intensities of continuous noise studied. The minimum duration of the stimulus beginning with which a subsequent increase in duration does not increase the number of correct responses is the same (385 ms) under all conditions of stimulus presentation. Broadband noise of any intensity increases the time of response to stimuli in the range of durations studied. At a noise of 52 dB, which is close to the threshold of full masking, the reaction time is not increased significantly compared to its estimation at a noise of 46 dB. The minimum duration of the stimulus has proved to be the stablest temporal parameter of the perception of movement of a sound source. Changes in the temporal parameters of sound perception at noise levels close to the threshold of full masking are discussed.     

Human perception of acoustic models of spatial sound translocation on the background of hearing and production of verbal signals (ontogenetic aspect)

Studied in the work was human perception of acoustic signals changing in amplitude on the background of production and hearing of syllables composed, from the ontogenetic viewpoint, of the earliest and the latest consonants and vowels —[pa] and [ly], as well as on the background of noise. It was shown that on the background of the syllable pronunciation their recognition occurred at the same rate; however, the number of mistakes with the syllable [ly] was statistically significantly greater than with the syllable [pa]. According to the data of paired comparison and dispersion analysis the differences at recognition of external stimuli on the background of: hearing [pa] — pronunciation [ly]; hearing [ly] — pronunciation [pa]; hearing [ly] — pronunciation [ly] are statistically significant. The most difficult task turned out to be the task of signal recognition on the background of isolated articulation, i.e., reproduction without voice. When evaluating sound stimuli on the background of noise, the correctness of signal recognition was more affected by masking as compared to the time of reaction. The results of signal perception on the background of the wideband noise differ qualitatively and quantitatively from the data of recognition both at intensive verbal activity and at passive hearing of speech.Translated from Zhurnal Evolyutsionnoi Biokhimii i Fiziologii, Vol. 40, No. 5, 2004, pp. 423–426.Original Russian Text Copyright © 2004 by Vartanyan, Tokareva, Lange.To the 100-Anniversary of N. N. Traugott     

Holarctic genetic structure and range dynamics in the woolly mammoth

Ancient DNA analyses have provided enhanced resolution of population histories in many Pleistocene taxa. However, most studies are spatially restricted, making inference of species-level biogeographic histories difficult. Here, we analyse mitochondrial DNA (mtDNA) variation in the woolly mammoth from across its Holarctic range to reconstruct its history over the last 200 thousand years (kyr). We identify a previously undocumented major mtDNA lineage in Europe, which was replaced by another major mtDNA lineage 32–34 kyr before present (BP). Coalescent simulations provide support for demographic expansions at approximately 121 kyr BP, suggesting that the previous interglacial was an important driver for demography and intraspecific genetic divergence. Furthermore, our results suggest an expansion into Eurasia from America around 66 kyr BP, coinciding with the first exposure of the Bering Land Bridge during the Late Pleistocene. Bayesian inference indicates Late Pleistocene demographic stability until 20–15 kyr BP, when a severe population size decline occurred.     

Human Long-Latency Auditory Evoked Potentials during Radial Motion of the Sound Source

Human long-latency auditory evoked potentials were studied during simulation with variable-amplitude pulse sequences from a sound source moving to and from the subject. The N1 peak parameters were shown to depend on an accurate estimate of the direction of the change in the distance to the sound source. Differences in the processing of signals that simulated the approaching and/or distancing of the sound source were found in the N1 and P2 component parameters of on- and off-responses as was a more pronounced long negative potential shift in the evoked response to the approaching source as compared to the distancing source.