Correlation of CD4+ T cell Count with Total Lymphocyte Count, Haemoglobin and Erythrocyte Sedimentation Rate Levels in Human Immunodeficiency Virus Type-1 Disease.

BACKGROUND: Studies in human immunodeficiency virus (HIV) infected adults have demonstrated association of total lymphocyte count (TLC) <1200/mm (3) and subsequent disease progression or mortality. The association of other surrogate makers such as haemoglobin (Hb), and erythrocyte sedimentation rate (ESR) with CD4 count and disease progression has also been suggested. This study was carried out to determine the relationship of CD4-positive T lymphocyte counts with TLC, Hb and ESR in HIV-infected individuals. METHODS: The study population comprised of 215 antiretroviral treatment naïve HIV-1 infected adults. The CD4 positive T cell counts, TLC, Hb and ESR of study participants were measured. Spearman's rank order correlation and Receiver Operating Characteristic were used for statistical analyses. RESULT: The sensitivity, specificity, positive and negative likelihood ratios for cut-off value of TLC <1200/mm (3) for predicting CD4 counts <200 cells/mm (3) and <350 cells/mm (3) were 9.4 %, 100 %, not measurable and 1.1, and 6.1 %, 98.8 %, 5.13 and 0.95, respectively. The association of Hb (<10,11,12 g/dl and <10,12,14 g/dl for CD4 counts <200 cells/mm (3) and <350 cells/mm (3) , respectively), and ESR (<10, 20 and 30 mm fall after 1 hour) with these two CD4 counts cut-off values were suboptimal. CONCLUSION: This study reveals the poor association of TLC, Hb, and ESR with CD4 counts in HIV infected adults, thus highlighting the need to review the utility of these surrogate markers, for predicting CD4 counts in people living with HIV/AIDS.

Acoustic characteristics, early experience, and endocrine status interact to modulate female zebra finches' behavioral responses to songs.

Female songbirds use male songs as an important criterion for mate selection. Properties of male songs are thought to indicate the male's quality as a potential mate. Song preferences in female zebra finches are known to be influenced by two factors--early auditory experience and the acoustic characteristics of males' songs. Studies often investigate song preferences by priming females with estrogen. However, estrogenic influences on song preferences have not been studied. We investigated the relative influence of early auditory experience, acoustic features of songs, and estrogen availability on song responsiveness in female zebra finches. Juvenile female zebra finches were tutored for 10 days with 40 songs per day with one of three acoustically different song types--simple songs, long-bout songs or complex songs. A fourth group of females was untutored. Aside from this brief song exposure, females were raised and maintained without exposure to male songs. During adulthood, females' behavioral responses to the three song types were tested under three hormone conditions--untreated, estradiol-treated and 1,4,6-androstatriene-3,17-dione (ATD)-treated (to lower endogenous estrogen). Based on the results of our study, four conclusions can be drawn. First, song responsiveness in female zebra finches is strongly affected by minimal early acoustic experience. Second, inexperienced female zebra finches are inherently biased to respond more to complex songs over other song types Third, although female zebra finches are inherently biased to respond more to complex songs, early acoustic experience may either reinforce or weaken this inherent responsiveness to complex songs. Fourth, estrogen selectively accentuates song responsiveness in acoustically-experienced female zebra finches.

Noradrenergic neurotoxin, N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine hydrochloride (DSP-4), treatment eliminates estrogenic effects on song responsiveness in female zebra finches (Taeniopygia guttata).

Female songbirds use male songs as an important criterion for mate selection. Several studies have reported that female songbirds prefer complex songs to other song types. In a recent study, the authors found that song responsiveness in female zebra finches (Taeniopygia guttata) is strongly modulated by circulating estrogen levels. The behavioral effects of estrogen are often mediated via norepinephrine (NE). The current study administered the noradrenergic neurotoxin, N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine hydrochloride (DSP-4) to estradiol-treated female zebra finches to investigate if estrogenic effects on song responsiveness are mediated via NE. The authors tested song responsiveness of adult female zebra finches for three acoustically different song types--simple, long-bout, and complex--under three treatment conditions, untreated, estradiol-treated, and estradiol + DSP-4-treated. Females only showed differential song responsiveness when treated with estradiol alone, responding more to complex songs. DSP-4 treatment eliminated this differential responsiveness. The results are discussed in the light of evidence from functional, neurochemical, and neuroanatomical studies that suggest that estrogenic effects on song processing might be mediated by NE.

Automated auditory recognition training and testing.

Laboratory training and testing of auditory recognition skills in animals is important for understanding animal communication systems that depend on auditory cues. Songbirds are commonly studied because of their exceptional ability to learn complex vocalizations. In recent years, mounting interest in the perceptual abilities of songbirds has increased the demand for laboratory behavioural training and testing paradigms. Here, we describe and demonstrate the success of a method for auditory discrimination experiments, including all the necessary hardware, training procedures and freely-available, versatile software. The system can run several behavioural training and testing paradigms, including operant (go-nogo, stimulus preference, and two-alternative forced choice) and classical conditioning tasks. The software and some hardware components can be used with any laboratory animal that learns and responds to sensory cues. The peripheral hardware and training procedures are designed for use with songbirds and auditory stimuli. Using the go-nogo paradigm of the training system, we show that adult zebra finches learn to recognize and correctly classify individual female calls and male songs. We also show that learning the task generalizes to new stimulus classes; birds that learned the task with calls subsequently learned to recognize songs faster than did birds that learned the task and songs at the same time.

Topography of rodent whisking--I. Two-dimensional monitoring of whisker movements.

During 'active touch' the rodent whiskers scan the environment in a series of repetitive movements ('whisks') generating afferent signals which transform the spatial properties of objects into spatio-temporal patterns of neural activity. Based upon analyses carried out in a single movement plane, it has been generally assumed that these trajectories are essentially uni-dimensional, although more complex movements have been described in some rodents. The present study was designed to examine this assumption and to more precisely characterize whisking topography by monitoring whisking trajectories along both the antero-posterior and dorso-ventral axes. Using optoelectronic monitoring techniques with high-spatio-temporal resolution, movement data were obtained from a population of vibrissae sampled at different locations on the mystacial pad in head-fixed rats isolated from the perturbing effects of contact. For a substantial proportion of the population of whisking movements sampled, the trajectories generated by a single whisker is most accurately described as occupying an expended two-dimensional space in which the A-P component predominates. However, the whisker system exhibits a considerable range of trajectory types, suggesting a high degree of movement flexibility. For each vibrissa position, it was possible to delineate a 'trajectory' domain-that portion of the animal's whisking space which is scanned by the movements of that vibrissa during whisking. Since the 'domains' of adjacent whiskers in the same row tend to overlap, synchronized movements of a subset of whiskers could generate a set of overlapping somatosensory fields analogous to overlapping retinal receptive fields. The organization of such trajectory domains within the rats' whisking space could provide the spatial component of the spatio-temporal integration process required to extract information about environmental features from the inputs generated by its recursive whisking movements.