Immuno-fluorescence staining patterns of leukocyte subsets in the skin of taurine and indicine cattle

The immuno-staining patterns of skin leukocytes were investigated in three breeds of cattle: Holstein-Friesian, Brahman and Santa Gertrudis of similar age before and after tick infestation. The antibodies specific for CD45 and CD45RO reacted with cells in the skin of all Holstein-Friesian cattle but did not react with cells in the skin of any Brahman cattle. The same antibodies reacted with cells from the skin of four (CD45) and seven (CD45RO) of twelve Santa Gertrudis cattle. The antibodies specific for T cells and γδ subset of T cells recognized cells from all three breeds of cattle. The antibody specific for MHC class II molecules labelled cells of mostly irregular shape, presumably dermal dendritic cells and/or macrophages and Langerhans cells. The antibody specific for granulocytes (mAb CH138) reacted with cells only in sections cut from skin with lesions. The antibody specific for CD25+ cells labelled regularly shaped cells that showed a wide range of intensities of staining

HighP–TNano-Mechanics of Polycrystalline Nickel

We have conducted highP–Tsynchrotron X-ray and time-of-flight neutron diffraction experiments as well as indentation measurements to study equation of state, constitutive properties, and hardness of nanocrystalline and bulk nickel. Our lattice volume–pressure data present a clear evidence of elastic softening in nanocrystalline Ni as compared with the bulk nickel. We show that the enhanced overall compressibility of nanocrystalline Ni is a consequence of the higher compressibility of the surface shell of Ni nanocrystals, which supports the results of molecular dynamics simulation and a generalized model of a nanocrystal with expanded surface layer. The analytical methods we developed based on the peak-profile of diffraction data allow us to identify “micro/local” yield due to high stress concentration at the grain-to-grain contacts and “macro/bulk” yield due to deviatoric stress over the entire sample. The graphic approach of our strain/stress analyses can also reveal the corresponding yield strength, grain crushing/growth, work hardening/softening, and thermal relaxation under highP–Tconditions, as well as the intrinsic residual/surface strains in the polycrystalline bulks. From micro-indentation measurements, we found that a low-temperature annealing (T < 0.4 Tm) hardens nanocrystalline Ni, leading to an inverse Hall–Petch relationship. We explain this abnormal Hall–Petch effect in terms of impurity segregation to the grain boundaries of the nanocrystalline Ni

Enzymes involved in the biosynthesis of leukotriene B 4 and prostaglandin E 2 are active in sebaceous glands

The expression of enzymes involved in leukotriene and prostaglandin signalling pathways, of interleukins 6 and 8 and of peroxisome proliferator-activated receptors in sebaceous glands of acne-involved facial skin was compared with those of non-involved skin of acne patients and of healthy individuals. Moreover, 5-lipoxygenase and leukotriene A 4 hydrolase were expressed at mRNA and protein levels in vivo and in SZ95 sebocytes in vitro (leukotriene A 4 hydrolase &amp;gt; 5-lipoxygenase), while 15-lipoxygenase-1 was only detected in cultured sebocytes. Cyclooxygenase-1 and cyclooxygenase-2 were also present. Peroxisome proliferator-activated receptors were constitutively expressed. Enhanced 5-lipoxygenase, cyclooxygenase 2 and interleukin 6 expression was detected in acne-involved facial skin. Arachidonic acid stimulated leukotriene B 4 and interleukin 6 release as well as prostaglandin E 2 biosynthesis in SZ95 sebocytes, induced abundant increase in neutral lipids and down-regulated peroxisome proliferator-activated receptor-α, but not receptor-γ1 mRNA levels, which were the predominant peroxisome proliferator-activated receptor isotypes in SZ95 sebocytes. In conclusion, human sebocytes possess the enzyme machinery for functional leukotriene and prostaglandin pathways. A comprehensive link between inflammation and sebaceous lipid synthesis is provided. © Springer-Verlag 2005

Transcriptome analysis of dominant-negative Brd4 mutants identifies Brd4-specific target genes of small molecule inhibitor JQ1.

The bromodomain protein Brd4 is an epigenetic reader and plays a critical role in the development and maintenance of leukemia. Brd4 binds to acetylated histone tails and activates transcription by recruiting the positive elongation factor P-TEFb. Small molecule inhibitor JQ1 competitively binds the bromodomains of Brd4 and displaces the protein from acetylated histones. However, it remains unclear whether genes targeted by JQ1 are mainly regulated by Brd4 or by other bromodomain proteins such as Brd2 and Brd3. Here, we describe anti-proliferative dominant-negative Brd4 mutants that compete with the function of distinct Brd4 domains. We used these Brd4 mutants to compare the Brd4-specific transcriptome with the transcriptome of JQ1-treated cells. We found that most JQ1-regulated genes are also regulated by dominant-negative Brd4 mutants, including the mutant that competes with the P-TEFb recruitment function of Brd4. Importantly, JQ1 and dominant-negative Brd4 mutants regulated the same set of target genes of c-Myc, a key regulator of the JQ1 response in leukemia cells. Our results suggest that Brd4 mediates most of the anti-cancer effects of JQ1 and that the major function of Brd4 in this process is the recruitment of P-TEFb. In summary, our studies define the molecular targets of JQ1 in more detail

Striatal and Behavioral Responses to Reward Vary by Socioeconomic Status in Adolescents

Disparities in socioeconomic status (SES) lead to unequal access to financial and social support. These disparities are believed to influence reward sensitivity, which in turn are hypothesized to shape how individuals respond to and pursue rewarding experiences. However, surprisingly little is known about how SES shapes reward sensitivity in adolescence. Here, we investigated how SES influenced adolescent responses to reward, both in behavior and the striatum—a brain region that is highly sensitive to reward. We examined responses to both immediate reward (tracked by phasic dopamine) and average reward rate fluctuations (tracked by tonic dopamine) as these distinct signals independently shape learning and motivation. Adolescents (n = 114; 12–14 years; 58 female) performed a gambling task during functional magnetic resonance imaging. We manipulated trial-by-trial reward and loss outcomes, leading to fluctuations between periods of reward scarcity and abundance. We found that a higher reward rate hastened behavioral responses, and increased guess switching, consistent with the idea that reward abundance increases response vigor and exploration. Moreover, immediate reward reinforced previously rewarding decisions (win–stay, lose–switch) and slowed responses (post reward pausing), particularly when rewards were scarce. Notably, lower-SES adolescents slowed down less after rare rewards than higher-SES adolescents. In the brain, striatal activations covaried with the average reward rate across time and showed greater activations during rewarding blocks. However, these striatal effects were diminished in lower-SES adolescents. These findings show that the striatum tracks reward rate fluctuations, which shape decisions and motivation. Moreover, lower SES appears to attenuate reward-driven behavioral and brain responses

Exploration is Associated with Socioeconomic Disparities in Learning and Academic Achievement in Adolescence

Why do adolescents from lower socioeconomic status (SES) backgrounds often underperform on tests of learning and academic achievement? Prior research points to the role of external environmental constraints, like limited financial and educational resources. Here, we ask how these constraints impact internal psychological decision strategies that, in turn, might shape learning disparities. Specifically, we tested the hypothesis that lower-SES adolescents adapt decision strategies to favor exploitation over exploration, which, in turn, may limit learning and academic achievement. Adolescents (n=124; 12-14 years old) from diverse SES backgrounds chose how much to explore or exploit during a reward decision task. Exploiting secured immediate reward, but reduced information about the task structure. Exploring led to uncertain reward, but more information, which could be leveraged for better outcomes later. Lower SES was associated with less exploration and more exploitation. Computational modeling revealed that reduced exploration was driven by higher loss aversion rather than differences in beliefs about the value of exploring. We also observed that exploratory tendencies partially explained the relationship between lower SES and reduced task performance, poorer school grades, and, in a lower-SES subsample, lower academic skills. Notably, exploratory behavior was not static but instead fluctuated in response to reward during the task: greater reward boosted subsequent exploration. These findings suggest that learning disparities across SES may reflect not only what resources are available within the early environment but also internal decision strategies that shape how adolescents interact with and, therefore, learn from their environment