Gaster R.S.,Medical Scientist Training Program |
Gaster R.S.,Stanford University |
Hall D.A.,Stanford University |
Wang S.X.,Stanford University
Nano Letters | Year: 2011
We report an autoassembly protein array capable of rapidly screening for aberrant antibody-antigen binding events. Our technique combines magnetic nanoparticle technology with proximity-based, magnetically responsive nanosensors for rapid (under 15 min) and high-density screening of antibody cross-reactivity at sensitivities down to 50 fM in a homogeneous assay. This method will enable the identification of the precise cause of aberrant or cross-reactive binding events in an easy-to-use, rapid, and high-throughput manner. © 2010 American Chemical Society.
Molet J.,University of California at Irvine |
Rice C.,University of California at Irvine |
Ji S.G.,Medical Scientist Training Program |
Solodkin A.,University of California at Irvine |
Baram T.Z.,University of California at Irvine
Molecular Psychiatry | Year: 2014
The cognitive effects of stress are profound, yet it is unknown if the consequences of concurrent multiple stresses on learning and memory differ from those of a single stress of equal intensity and duration. We compared the effects on hippocampus-dependent memory of concurrent, hours-long light, loud noise, jostling and restraint (multimodal stress) with those of restraint or of loud noise alone. We then examined if differences in memory impairment following these two stress types might derive from their differential impact on hippocampal synapses, distinguishing dorsal and ventral hippocampus. Mice exposed to hours-long restraint or loud noise were modestly or minimally impaired in novel object recognition, whereas similar-duration multimodal stress provoked severe deficits. Differences in memory were not explained by differences in plasma corticosterone levels or numbers of Fos-labeled neurons in stress-sensitive hypothalamic neurons. However, although synapses in hippocampal CA3 were impacted by both restraint and multimodal stress, multimodal stress alone reduced synapse numbers severely in dorsal CA1, a region crucial for hippocampus-dependent memory. Ventral CA1 synapses were not significantly affected by either stress modality. Probing the basis of the preferential loss of dorsal synapses after multimodal stress, we found differential patterns of neuronal activation by the two stress types. Cross-correlation matrices, reflecting functional connectivity among activated regions, demonstrated that multimodal stress reduced hippocampal correlations with septum and thalamus and increased correlations with amygdala and BST. Thus, despite similar effects on plasma corticosterone and on hypothalamic stress-sensitive cells, multimodal and restraint stress differ in their activation of brain networks and in their impact on hippocampal synapses. Both of these processes might contribute to amplified memory impairments following short, multimodal stress. © 2014 Macmillan Publishers Limited All rights reserved.
Qian W.,University of Pittsburgh |
Choi S.,Medical Scientist Training Program |
Choi S.,University of Pittsburgh |
Gibson G.A.,University of Pittsburgh |
And 3 more authors.
Journal of Cell Science | Year: 2012
Mitochondrial fission and fusion cycles are integrated with cell cycle progression. In this paper, we demonstrate that the inhibition of mitochondrial fission protein Drp1 causes an unexpected delay in G2/Mcell cycle progression and aneuploidy. In investigating the underlying molecular mechanism, we revealed that inhibiting Drp1 triggers replication stress, which is mediated by a hyperfused mitochondrial structure and unscheduled expression of cyclin E in the G2 phase. This persistent replication stress then induces an ATM-dependent activation of the G2 to M transition cell cycle checkpoint. Knockdown of ATR, an essential kinase in preventing replication stress, significantly enhanced DNA damage and cell death of Drp1-deficienct cells. Persistent mitochondrial hyperfusion also induces centrosomal overamplification and chromosomal instability, which are causes of aneuploidy. Analysis using cells depleted of mitochondrial DNA revealed that these events are not mediated by the defects in mitochondrial ATP production and reactive oxygen species (ROS) generation. Thus dysfunctional mitochondrial fission directly induces genome instability by replication stress, which then initiates the DNA damage response. Our findings provide a novel mechanism that contributes to the cellular dysfunction and diseases associated with altered mitochondrial dynamics.
Sanders J.L.,Medical Scientist Training Program |
Sanders J.L.,University of Pittsburgh |
Fitzpatrick A.L.,University of Washington |
Boudreau R.M.,University of Pittsburgh |
And 6 more authors.
Journals of Gerontology - Series A Biological Sciences and Medical Sciences | Year: 2012
Background. Most studies of leukocyte telomere length (LTL) focus on diagnosed disease in one system. A more encompassing depiction of health is disease burden, defined here as the sum of noninvasively measured markers of structure or function in different organ systems. We determined if (a) shorter LTL is associated with greater age-related disease burden and (b) shorter LTL is less strongly associated with disease in individual systems or diagnosed chronic conditions (cardiovascular disease, stroke, pulmonary disease, diabetes, kidney disease, arthritis, or depression). Methods. LTL was measured by Southern blots of terminal restriction fragment length. Age-related disease was measured noninvasively and included carotid intima-media thickness, lung vital capacity, white matter grade, cystatin-C, and fasting glucose; each graded 0 (best tertile), 1 (middle tertile), or 2 (worst tertile) and summed (0 to 10) to estimate disease burden. Of 419 participants randomly selected for LTL measurement, 236 had disease burden assessed (mean [SD] age 74.2 [4.9] years, 42.4% male, 86.8% white, and 13.2% black). Results. Mean (SD) LTL was 6,312 (615) bp, and disease score was 4.7 (2.1) points. An SD higher disease score (β [SE] =-132  bp, p <. 01), age (β [SE] =-107 , p =. 02) or carotid thickness (β [SE] =-95  bp, p =. 02) was associated with shorter LTL, but diagnosed conditions or number of conditions were not associated with LTL. Disease score attenuated the effect of age on LTL by 35%. Conclusion. LTL was associated with a characterization of age-related disease burden across multiple physiologic systems, which was comparable to, but independent of, its association with age. © 2011 The Author.
Neuberger E.W.I.,Johannes Gutenberg University Mainz |
Jurkiewicz M.,Medical Scientist Training Program |
Moser D.A.,Johannes Gutenberg University Mainz |
Simon P.,Johannes Gutenberg University Mainz
Drug Testing and Analysis | Year: 2012
Gene doping - or the abuse of gene therapy - will continue to threaten the sports world. History has shown that progress in medical research is likely to be abused in order to enhance human performance. In this review, we critically discuss the progress and the risks associated with the field of erythropoietin (EPO) gene therapy and its applicability to EPO gene doping. We present typical vector systems that are employed in ex vivo and in vivo gene therapy trials. Due to associated risks, gene doping is not a feasible alternative to conventional EPO or blood doping at this time. Nevertheless, it is well described that about half of the elite athlete population is in principle willing to risk its health to gain a competitive advantage. This includes the use of technologies that lack safety approval. Sophisticated detection approaches are a prerequisite for prevention of unapproved and uncontrolled use of gene therapy technology. In this review, we present current detection approaches for EPO gene doping, with a focus on blood-based direct and indirect approaches. Gene doping is detectable in principle, and recent DNA-based detection strategies enable long-term detection of transgenic DNA (tDNA) following in vivo gene transfer. © 2012 John Wiley & Sons, Ltd.