Low-voltage-exposure-enabled hydrogen silsesquioxane bilayer-like process for three-dimensional nanofabrication

We report a bilayer-like electron-beam lithographic process to obtain three-dimensional (3D) nanostructures by using only a single hydrogen silsesquioxane (HSQ) resist layer. The process utilizes the short penetration depth of low-energy (1.5 keV) electron irradiation to first obtain a partially cross-linked HSQ top layer and then uses a high-voltage electron beam (30 keV) to obtain self-aligned undercut (e.g. mushroom-shaped) and freestanding HSQ nanostructures. Based on the well-defined 3D resist patterns, 3D metallic nanostructures were directly fabricated with high fidelity by just depositing a metallic layer. As an example, Ag-coated mushroom-shaped nanostructures were fabricated, which showed lower plasmon resonance damping compared to their planar counterparts. In addition, the undercut 3D nanostructures also enable more reliable lift-off in comparison with the planar nanostructures, with which high-quality silver nanohole arrays were fabricated which show distinct and extraordinary optical transmission in the visible range.

"Sketch and Peel" Lithography for High-Resolution Multiscale Patterning

We report a unique lithographic process, termed "Sketch and Peel" lithography (SPL), for fast, clean, and reliable patterning of metallic structures from tens of nanometers to submillimeter scale using direct writing technology. The key idea of SPL process is to define structures using their presketched outlines as the templates for subsequent selective peeling of evaporated metallic layer. With reduced exposure area, SPL process enables significantly improved patterning efficiency up to hundreds of times higher and greatly mitigated proximity effect compared to current direct writing strategy. We demonstrate that multiscale hierarchical metallic structures with arbitrary shapes and minimal feature size of ∼15 nm could be defined with high fidelity using SPL process for potential nanoelectronic and nano-optical applications.

Surface enhanced Raman scattering of gold nanoparticles supported on copper foil with graphene as a nanometer gap

Gaps with single-nanometer dimensions (<10 nm) between metallic nanostructures enable giant local field enhancements for surface enhanced Raman scattering (SERS). Monolayer graphene is an ideal candidate to obtain a sub-nanometer gap between plasmonic nanostructures. In this work, we demonstrate a simple method to achieve a sub-nanometer gap by dewetting a gold film supported on monolayer graphene grown on copper foil. The Cu foil can serve as a low-loss plasmonically active metallic film that supports the imaginary charge oscillations, while the graphene can not only create a stable sub-nanometer gap for massive plasmonic field enhancements but also serve as a chemical enhancer. We obtained higher SERS enhancements in this graphene-gapped configuration compared to those in Au nanoparticles on Cu film or on graphene-SiO2-Si. Also, the Raman signals measured maintained their fine features and intensities over a long time period, indicating the stability of this Au-graphene-Cu hybrid configuration as an SERS substrate.

Characterization of the nuclear localization signals of duck circovirus replication proteins

Duck circovirus (DuCV) possess a circular, single-stranded DNA genome that requires the replication protein (Rep) for its replication. Based on the viral genotype, there are two categories of Rep proteins: Rep1 and Rep2. To characterize the nuclear localization signals (NLSs) conferring the nuclear localization of the Rep proteins, defined coding regions of the rep gene of two genotypes of DuCV were cloned and co-expressed with the red fluorescent protein DsRed2. The results showed that deleting the putative N-terminal NLS located at amino acid residues 10-37 of Rep1 and Rep2 abrogated nuclear translocation, while deleting the putative C-terminal NLS located at residues 244-274 of Rep1 did not significantly alter its subcellular localization, confirming that only the NLS located at residues 10-37 in the N-termini of the Rep proteins had nuclear targeting activity.

Reliable fabrication of plasmonic nanostructures without an adhesion layer using dry lift-off

Lift-off is the most commonly used pattern-transfer method to define lithographic plasmonic metal nanostructures. A typical lift-off process is realized by dissolving patterned resists in solutions, which has the limits of low yield when not using adhesion layers and incompatibility with the fabrication of some specific structures and devices. In this work, we report an alternative 'dry' lift-off process to obtain metallic nanostructures via mechanical stripping by using the advantage of poor adhesion between resists and noble metal films. We show that this dry stripping lift-off method is effective for both positive- and negative-tone resists to fabricate sparse and densely-packed plasmonic nanostructures, respectively. In particular, this method is achieved without using an adhesion layer, which enables the mitigation of plasmon damping to obtain larger field enhancement. Dark-field scattering, one-photon luminescence and surface-enhanced Raman scattering measurements were performed to demonstrate the improved quality factor of the plasmonic nanostructures fabricated by this dry lift-off process.

Intranasal administration of TAT-haFGF(₁₄₋₁₅₄) attenuates disease progression in a mouse model of Alzheimer's disease

Human acidic fibroblast growth factor (haFGF), a neurotrophin-like growth factor in the brain, plays important roles in the development, differentiation and regeneration of brain neurons, which makes it potential to treat Alzheimer's disease (AD). In this study, haFGF(14-154) and TAT-haFGF(14-154) (haFGF(14-154) fused with the cell-penetrating peptide transactivator of transcription protein transduction domain (TAT-PTD)) were intranasally administrated for 5 weeks to investigate the effects on senescence-accelerated mouse prone-8 (SAMP8) mice (a mouse model of AD). Results showed that TAT-PTD could increase the concentration of haFGF in the brain significantly, and TAT-haFGF(14-154) was more effective than haFGF(14-154) in the same dosage (300 μg/kg). Importantly, TAT-haFGF(14-154) improved the learning and memory abilities of SAMP8 mice in the behavioral test, and promoted the function of cholinergic system by measuring the relevant biomarkers (acetylcholine (ACh) level, acetylcholinesterase (AChE) and choline acetyltransferase (ChAT) activities). TAT-haFGF(14-154) also significantly reduced β-amyloid protein(1-42) (Aβ(1-42)) deposits as well as the levels of Aβ soluble forms in the mice brains and prevented the neurons from apoptosis. Besides, the oxidative stress impairment in the brain and serum was also ameliorated. The results suggest that TAT-haFGF(14-154) could attenuate the disease progression of SAMP8 AD mice, and the mechanism is related to the regulation of neurons microenvironment including neurotransmitters, Aβ pathology and oxidative stress.

P3-13-05: Analysis of Heart Dose-Volume Parameters and Cardiac Events among Node Positive Breast Cancer (NPBC) Patients Treated with Three-Dimensional Conformal Radiation Therapy (3D-CRT)

Background

For NPBC patients the use of regional nodal irradiation (RNI) to the supraclavicular, axillary, internal mammary lymph nodes (IMN) in addition to the chest wall and/or breast can maximize locoregional control and improve overall survival. However, comprehensive RNI for breast cancers located on the left side has been linked to late cardiac morbidity, potentially lessening the therapeutic benefit of treatment. The optimal radiation dose-volume constraints for the heart in this setting are not fully understood. We examined NPBC patients treated with RNI using 3D-CT based radiation therapy (RT) to evaluate cardiac dose and incidence of cardiac events.

Methods: Between 2000 and 2007, 150 NPBC patients were treated with RNI following lumpectomy or mastectomy using 3D-CRT. In all cases, treatment target and normal tissue volumes were delineated on treatment CT scans. The heart contour included the ventricles and the left atrium. The dose-volume histogram of the cardiac doses delivered and the incidence of cardiac events is reported.

Results: Median follow-up of surviving patients is 7 (1-10.6) years. Median patient age is 50 (27-91). 52.35% are premenopausal, 75.7% estrogen receptor positive, 66.3% progesterone receptor positive and 15.92% HER-2 positive. Mean positive lymph nodes is 5 (1-29). Extracapsular extension is present in 47.31%. Mean microscopic tumor size is 3.73 (0.1-21) cm. The IMN receive &gt; 40 Gy in 65.5%. 94% had chemotherapy, and in 82.3% it was anthracycline-based. At the time of RT, 12.2% smoked, 9.5% had diabetes, 32.4% with hypertension, and 4.7% with a history of coronary artery disease.

There was 1 (0.7%) right sided patient with cardiac events and 4 (2.7%) left sided experiencing cardiac events (p = 0.121, Fisher's Exact test). A total of 10 cardiac diagnoses were experienced among the 5 patients: coronary artery disease with myocardial infarction (3), congestive heart failure (2), cardiomyopathy (2), and arrhythmia (3). The median time interval to onset of the events is 2.5 years (0-4.3 years).

The cardiac doses among 150 patients are as follows: mean V25 is 5.7, (0.0 - 20.0%), V25 is &lt; 9 % in 74.4% of patients, mean V45 is 1.8% (0-13.3%), V45 is &lt; 5.5% in 91.8%. The mean maximum point dose is 42.8 Gy, and the mean heart dose is 5.6 Gy (0.2−25.3 Gy). The mean V25 and V45 in those 5 patients with a cardiac event is 6.7% (0.9−11.9%) and 3.7% (0-6.6%), respectively; in the 145 remaining patients, 5.7% (0-20.0%) and 1.7% (0-13.3%), respectively. The mean heart dose in those with an event is 5.2 Gy (2.4−7.3 Gy) versus 5.6 Gy (0.2−25.3 Gy) in the remaining patients.

Conclusions: The cardiac event rate among these NPBC patients treated with RNI and anthracycline-based chemotherapy is low. However, those patients with cardiac events have a higher mean V45. No other dose-volume relationships are discernible. Additional analysis using 3DCRT volumes are important to validate these findings and better define the dose-volume parameters for cardiac toxicity.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P3-13-05.

Lymphedema and arm symptoms following three-dimensional conformal radiation therapy (3DCRT) for node-positive breast cancer (BC) patients

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Background: Regional nodal irradiation for lymph node (LN) positive BC after lumpectomy/mastectomy can be subject to controversy due to the potential for treatment morbidity particularly lymphedema. Little is known about lymphedema and other arm morbidity rates after 3DCRT approaches.

Methods: 172 LN positive BC cases treated from 2000 to 2007 using 3-DCRT and Dose Volume Histogram analyses were studied. All cases underwent axillary node dissection (AND). Axillary target volumes (ATV) were delineated on all treatment planning CT scans. Field arrangement and beam modifications were selected to deliver a min of 45 Gy to 90% of the ATV. Post-treatment bilateral arm circumference measurements (96%) and patient reported ipsilateral arm symptoms (thickness, heaviness, tingling, numbness) were recorded.

Results: Median follow-up was 83.7 months. Median (med) patient age was 50. 52% were premenopausal. 76/66% had positive estrogen/progesterone receptors and 16% were HER2+. 52% underwent lumpectomy and 46% mastectomy. Median number of LN removed was 17 (1-46), number +LN was 3 (1-29), and tumor size was 3.7 cm. For 79 patients with separate AND the mean resected axillary volume was 157.8 cc (med 171 cc, range 25-472 ). The mean contoured ATV was 69 cc (med 58cc, range 16-608). On average 95% of the ATV was covered by a med of 44.7 Gy. Local control was achieved in 94.7% regional LN control in 99.4%. 16.7% met criteria for lymphedema (> 2 cm difference in circumference). Arm symptoms were reported by 51 (30%) of these 20 (39%) had measured circumference change > 2 cm. Referral to physical therapy was documented for 15% for reduced ROM but at last follow-up noted in 2.3%. The measured lymphedema rate was higher in patients who had mastectomy – 22 v. 11% (p=0.042) and worse with increasing resected axillary dissection volumes (p=0.032), ATV volume (p=0.883), and RT dose inhomgeneity coefficient (p = 0.049).

Conclusions: Measured lymphedema rates following AND and 3-DCRT in this study were similar to those reported for AND in randomized studies compared to sentinel node. Careful attention to 3DCRT methods may help optimize lymphedema rates.

GABAergic excitotoxicity injury of the immature hippocampal pyramidal neurons' exposure to isoflurane

BACKGROUND

Certain anesthetics exhibit neurotoxicity in the brains of immature but not mature animals. γ-Aminobutyric acid (GABA), the primary inhibitory neurotransmitter in the adult brain, is excitatory on immature neurons via its action at the GABAA receptor, depolarizing the membrane potential and inducing a cytosolic Ca2+ increase ([Ca2+]i), because of a reversed transmembrane chloride gradient. Recent experimental data from several rodent studies have demonstrated that exposure to isoflurane during an initial phase causes neuronal excitotoxicity and apoptosis. GABAA receptor-mediated synaptic voltage-dependent calcium channels' (VDCCs) overactivation and Ca2+ influx are involved in these neural changes.

METHODS

We monitored [Ca2+]i using Fluo-4 AM fluorescence imaging. Using whole-cell patch clamp techniques, IVDCC (voltage-dependent calcium channel currents) were recorded from primary cultures of rat hippocampal neurons (5-day culture) exposed to isoflurane. To further investigate the neurotoxicity of high cytosolic-free calcium after isoflurane in a dose- and time-dependent manner, the possibility of increased caspase-3 levels was evaluated by Western blot and quantitative real-time polymerase chain reaction. Statistical significance was assessed using the Student t test or 1-way analysis of variance followed by the Tukey post hoc test.

RESULTS

Under control conditions, isoflurane enhanced the GABA-induced [Ca2+]i increase in a dose-dependent manner. Dantrolene and nicardipine markedly inhibited this enhancement mediated by isoflurane. Moreover, in Ca2+-free media, pretreatment with isoflurane did not show any influence on the caffeine-induced increase of [Ca2+]i. Similarly, using whole-cell recording, isoflurane increased the peak amplitude of IVDCC in the cultured neurons from rat hippocampus by depolarization pulses. Isoflurane (0.25, 0.5, 0.75, and 1 minimum alveolar concentration [MAC]) potentiated IVDCC peak current amplitude by 109.11%±9.03%, 120.56%±11.46%, 141.33%±13.87%, and 146.78%±15.87%, respectively. To analyze variation in protein levels, the effect of treatments with isoflurane on caspase-3 activity was dose- and time-dependent, reaching a maximal caspase-3 activity after exposure to 1 MAC for 6 hours (P<0.001). However, in the mRNA levels, hippocampal caspase-3 mRNA levels began to be significantly increased in isoflurane-treated developing rat hippocampal neurons after 6 hours of exposure to 0.25 MAC isoflurane (P<0.001).

CONCLUSIONS

Isoflurane-mediated enhancement of GABA-triggered [Ca2+]i release results from membrane depolarization with subsequent activation of VDCCs and further Ca2+-induced Ca2+ release from the ryanodine-sensitizing Ca2+ store. An increase in [Ca2+]i, caused by activation of the GABAA receptor and opening of VDCCs, is necessary for isoflurane-induced calcium overload of immature rat hippocampal neurons, which may be involved in the mechanism of an isoflurane-induced neurotoxic effect in the developing rodent brain.

PTPH1 cooperates with vitamin D receptor to stimulate breast cancer growth through their mutual stabilization

Tyrosine phosphorylation is tightly regulated by protein tyrosine kinases (PTKs) and protein tyrosine phosphatases (PTPs), and plays a critical role in malignant transformation and progression. While PTKs have a well-established role in regulating breast cancer growth, contribution of PTPs remains mostly unknown. Here, we report that the tyrosine phosphatase PTPH1 stimulates breast cancer growth through regulating vitamin D receptor (VDR) expression. PTPH1 was shown to be over-expressed in 49% of primary breast cancer and levels of its protein expression positively correlate with the clinic metastasis, suggesting its oncogenic activity. Indeed, PTPH1 promotes breast cancer growth by a mechanism independent of its phosphatase activity but dependent of its stimulatory effect on the nuclear receptor VDR protein expression and depletion of induced VDR abolishes the PTPH1 oncogenic activity. Additional analyses showed that PTPH1 binds VDR and increases its cytoplasmic accumulation leading to their mutual stabilization and stable expression of a nuclear localization deficient VDR abolishes the growth-inhibitory activity of the receptor independent of 1, 25-dihydroxyvitamin D3 (vitamin D3). These results reveal a new paradigm in which a protein tyrosine phosphatase may stimulate breast cancer growth through increasing cytoplasmic translocation of a nuclear receptor leading to their mutual stabilization.

Isoflurane enhances spontaneous Ca(2+) oscillations in developing rat hippocampal neurons in vitro

BACKGROUND

During the nervous system development, spontaneous synchronized Ca(2+) oscillations are thought to possess integrative properties because their amplitude and frequency can influence the patterning of neuronal connection, neuronal differentiation, axon outgrowth, and long-distance wiring. Accumulating studies have confirmed that some drugs such as volatile anesthetic isoflurane produced histopathologic changes in the central nervous system in juvenile animal models. Because the hippocampus plays an important role in learning and memory, the present work was designed to characterize the Ca(2+) oscillations regulated by volatile anesthetic isoflurane in primary cultures of developing hippocampal neurons (5-day-cultured).

METHODS

Primary cultures of rat hippocampal neurons (5-day-cultured) were loaded with the Ca(2+) indicator Fluo-4AM (4 microM) and were studied with a confocal laser microscope.

RESULTS

Approximately 22% of 5-day-cultured hippocampal neurons exhibited typical Ca(2+) oscillations. These oscillations were dose-dependently enhanced by isoflurane (EC50 0.5 MAC, minimum alveolar concentration) and this effect could be reverted by bicuculline (50 microM), a specific gamma-aminobutyric acid (GABA(A)) receptor antagonist.

CONCLUSION

Unlike its depressant effect on the Ca(2+) oscillations in adult neurons in previous researches, isoflurane dose-dependently enhanced calcium oscillations in developing hippocampal neurons by activating GABA(A) receptors, a major excitatory receptor in synergy with N-methyl-d-aspartate receptors at the early stages of development. It may be involved in the mechanism of an isoflurane-induced neurotoxic effect in the developing rodent brain.

Endotoxin tolerance of RAW264.7 correlates with p38-dependent up-regulation of scavenger receptor-A

Pre-exposure to lipopolysaccharide (LPS) leads to hyposensitivity to secondary LPS stimulation, known as endotoxin tolerance. The role of macrophage scavenger receptor-A (SR-A) in endotoxin tolerance is unknown. In this study, LPS was shown to induce SR-A expression in the mouse macrophage cell line, RAW264.7, in dose- and time-dependent manners, which correlated with inflammatory cytokine suppression in RAW264.7 on secondary LPS stimulation. Over-expression of SR-A in RAW264.7 suppressed tumour necrosis factor (TNF)-alpha release and nuclear factor (NF)-kappa B activation, demonstrating the involvement of SR-A in endotoxin tolerance. LPS-pre-treated RAW264.7 cells could bind and internalize more fluorescein isothiocyanate (FITC)-LPS than untreated cells and both the SR-A ligand, fucoidan, and anti-SR-A 2F8 antibodies completely suppressed LPS-induced binding and internalization of FITC-LPS by RAW264.7. LPS-induced SR-A expression on RAW264.7 was completely suppressed by the p38-specific inhibitor, SB203580, but not by inhibition of toll-like receptor 4 (TLR4) signalling with MTS510, demonstrating that p38- but not TLR4-dependent up-regulation of SR-A was involved in endotoxin tolerance through binding and internalization of LPS.

Condylomata gigantea in a male transsexual

Summary

As the incidence of genital warts increases, warts arising in the mouth, throat and other sites can occasionally be seen. Condyloma gigantea in genital sites are often reported, but literature on genital warts in transsexuals is rare. We present a case of C. gigantea in a 23-year-old male-to-female transsexual, whose warts arose on the transplanted skin of a neovagina and in the perianal region. We conclude that although C. gigantea can occur in transsexuals, the best way to treat it is not clear.