Bright Foci Research Articles

Novel protein products encoded by upstream open reading frames of the MYCN gene in pediatric embryonal tumors.

The MYCC and MYCN loci are each associated with two upstream open reading frames (uORFs) potentially encoding small proteins (9-21 kDa). We previously demonstrated that uORFs mrtl and MYCHEX1 of MYCC are translated, and their protein products may function to regulate the expression of the "parent" oncogene. We hypothesized that a similar relationship might exist between MYCN and its two uORFs: MYCNOT and MNOP, and investigated the uORF-encoded proteins associated with MYCN to confirm their expression and intracellular location in neuroblastoma and medulloblastoma cells and tissues. MNOP, MYCNOT, mrtl, and MYCHEX1 were readily detected via reverse transcription polymerase chain reaction and Western blot analysis in tumor cell lines. In tumor tissue, MNOP protein expression was confirmed; however, MCYNOT generated from alternative splicing MYCNΔ1b mRNA was not detected. Immunofluorescence staining of MYCNOT displayed multiple bright foci in the nucleus and diffuse staining in the cytoplasm, suggesting that this small protein may function in both the nucleus and cytoplasm. Upon JQ1 treatment, MYCN, MYCNOT, and mrtl decreased substantially or disappeared completely in three different tumor cell lines. Significant levels of apoptosis were observed in each pediatric embryonal tumor cell line but not T47D breast carcinoma cells, suggesting that response to JQ1 transcriptional inhibition is greatest in tumor cells, which depend on MYC to maintain an undifferentiated phenotype. In conclusion, both MYCN uORF-encoded proteins MNOP and MYCNOT, together with the two MYCC uORF-encoded proteins mrtl and MYCHEX1 were detected simultaneously in tumor cell lines and tumor tissues. These four distinct proteins are translated from the "5'-untranslated region" of MYCN or MYCC mRNAand display consistent distribution patterns within the cell. Additional studies to further elucidate the physiological and pathological roles of these uORF-encoded proteins are warranted, as insights gained could inform new strategies for modulating MYC-family oncogenes by targeting their uORFs.

Uterine junctional zone and adenomyosis: comparison of MRI, transvaginal ultrasound and histology.

The uterine junctional zone is the subendometrial area in the myometrium that contributes to peristalsis and aids in spermatozoa and blastocyst transport. Alterations in the appearance of the junctional zone on transvaginal sonography (TVS) or magnetic resonance imaging (MRI) are associated with adenomyosis. The lack of standardization of description of its appearance and ill-defined boundaries on both histology and imaging hamper understanding of the junctional zone and limit its role in the diagnosis of adenomyosis. The objectives of this review were to investigate the accordance in definition of the junctional zone across different diagnostic approaches and to examine how imaging findings can be linked to histological findings in the context of diagnosis of adenomyosis. A comprehensive literature review was conducted of articles describing the appearance on imaging and the histological structure of the uterine junctional zone. Our review suggests that the junctional zone is distinguished from the middle and outer myometrium by gradual changes in smooth-muscle cell density, extracellular space, connective tissue, water content and vascular properties. However, while the signal intensity from the junctional zone to the middle myometrium changes abruptly on MRI, the histopathological changes are gradual and its border may be difficult or impossible to distinguish on two-dimensional TVS. Moreover, the thickness of the junctional zone measured on MRI is larger than that measured on TVS. Thus, these two imaging modalities reflect this zone differently. Although a thickened junctional zone is often used to diagnose adenomyosis on MRI, the presence of adenomyosis can be described more accurately as interruptions of the junctional zone by endometrial tissue, which leads to direct signs on imaging such as subendometrial lines and buds on two- and three-dimensional TVS or bright foci on MRI. The histopathological criteria for diagnosis are based on enlargement of the uterus with severe adenomyosis, and might not reflect its early stages. Clinicians should be aware that findings on MRI cannot be extrapolated readily to ultrasound. An understanding of this is necessary when investigating the uterine junctional zone as a functional unit and the association between visualization of direct features of adenomyosis in the junctional zone and clinical symptoms. © 2022 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Establishment of an indirect immunofluorescence assay for the detection of African swine fever virus antibodies

African swine fever (ASF) continues to cause enormous economic loss to the global pig industry. Since there is no safe and effective vaccine, accurate and timely diagnosis of ASF is essential to implement control measures. Indirect immunofluorescence assay (IFA) is a gold standard serological method recommended by the World Organization for Animal Health (WOAH). In this study, we used primary fetal kidney cells to establish a wild boar cell line (BK2258) that supported the efficient replication of ASF virus (ASFV) SD/DY-I/21 and showed visible cytopathic effect (CPE). Moreover, using BK2258, we established a sensitive and specific IFA for ASFV antibody detection. To standardize and evaluate the performance of this assay, we used serum samples from pigs infected with the low virulent genotype I SD/DY-I/21 and genotype II HLJ/HRB1/20, and immunized with the vaccine candidate HLJ/18-7GD, field samples, and negative serum samples. The IFA reacted with the ASFV-positive sera and displayed bright fluorescence foci. There was no non-specific green fluorescence due to cellular senescence or other cell damage-causing factors. Compared to a commercial indirect enzyme-linked immunosorbent assay (iELISA), ASFV antibodies were detected 1–4 days earlier using our IFA. The detection limits of the IFA and iELISA for the same ASFV-antibody positive serum samples were 1:25,600 and 1:6,400, respectively, indicating that the IFA is more sensitive than iELISA. The newly established IFA was highly specific and did not cross-react with sera positive for six other important porcine pathogens (i.e., Classical swine fever virus (CSFV), Porcine reproductive and respiratory syndrome virus (PRRSV), Porcme circovirus type 2 (PCV2), Pseudorabies virus (PRV), Foot-and-Mouth disease virus type O (FMDV/O), and Porcine epidemic diarrhea virus (PEDV)). This study thus provides a sensitive, specific, and reliable detection method that is suitable for the serological diagnosis of ASF.

Regulation of T3SS synthesis, assembly and secretion in Pseudomonas aeruginosa

T3SS is an important virulence factor of Pseudomonas aeruginosa and has a central role in the infection process. However, the functional regulation of the T3SS by environmental signals is poorly understood. In our lab, we use fluorescence microscopy to study protein kinetics in real-time in live cells. In P. aeruginosa, results have shown that T3SS appears as bright foci at the cell membrane with no specific arrangement. In addition, T3SS is tightly controlled as it appears under a limited time period with the highest intensity at 3 h then disappears. Surprisingly, only 2.5% of the all assembled T3SS in the population have detectable ExoS synthesis. While T3SS assembly and ExoS synthesis increased under high salt concentration, they unexpectedly were not affected by different cyclic di-GMP levels. On the other hand, T3SS itself has an effect on the cyclic di-GMP levels inside the cell. Data have shown that despite T3SS in P. aeruginosa and Yersinia enterocolitica belong to the same the group, the two systems differentiate greatly in activity and regulation. We can conclude that every T3SS is unique and thus further studies are needed to elucidate the functional regulation of each system to better help effective inhibitor design.

Fundus autofluorescence in detection of embolus in retinal artery occlusion

Fundus autofluorescence (FAF) is a noninvasive imaging tool helpful in various retinal and choroidal diseases. In this series, we report the utility of FAF in two cases of retinal artery occlusion (RAO). Cholesterol embolus was seen as a bright hyper autofluorescent foci on FAF in a case of branch RAO. Platelet fibrin embolus exhibited minimal hyper autofluorescence in another case of multiple RAO in contrast to bright hyper autofluorescence of cholesterol embolus. Fundus autofluorescence may be helpful in easier identification of cholesterol embolus in RAO and helps in differentiating it from platelet fibrin embolus.

MRI in the Diagnosis and Treatment Response Assessment of Chronic Nonbacterial Osteomyelitis in Children and Adolescents.

To explain the central role of magnetic resonance imaging (MRI) in the diagnosis and follow-up of chronic nonbacterial osteomyelitis (CNO) in children and adolescents, centering on practical technical aspects and salient diagnostic features. In the absence of conclusive clinical features and widely accepted laboratory tests, including validated disease biomarkers, MRI (whether targeted or covering the entire body) currently plays an indispensable role in the diagnosis and therapy response assessment of CNO. Whole-body MRI, which is the reference imaging standard for CNO, can be limited to a short tau inversion recovery (STIR) coronal image set covering the entire body and a STIR sagittal set covering the spine, an approximately 30-min examination with no need for intravenous contrast or diffusion-weighted imaging. The hallmark of CNO is periphyseal (metaphyseal and/or epi-/apophyseal) osteitis, identified as bright foci on STIR, with or without inflammation of the adjacent periosteum and surrounding soft tissue. Response to bisphosphonate treatment for CNO has some unique MRI findings that should not be mistaken for residual or relapsing disease. Diagnostic features and treatment response characteristics of MRI in pediatric CNO are discussed, also describing the techniques used, pitfalls encountered, and differential diagnostic possibilities considered during daily practice.

The tailoring effect of two symmetrically distributed vortices on circular Airy beam

We investigate the tailoring effect of the point vortices on the foci of the circular Airy vortex beam (CAVB). Two optical vortices (OVs) with same or opposite topological charges (TCs) are symmetrically loaded on the beam. It is found that the loading distance between these two OVs (denoted as dv) can significantly tailor the auto-focusing behaviour of the beam. For two OVs with same TCs, as dv increases from 0 to infinite, the intensity pattern at the focal plane changes from a ring to a bright spot. For opposite OVs, when dv is near 0 or very large, there is a bright foci. But within a certain range, two foci are generated at the focal plane. Good agreements have been achieved between simulations and experiments. We qualitatively explain the tailoring phenomena from the perspective of the inward energy flow of the main ring of CAVB and the interaction between two OVs. The tailoring effect of dv of the two OVs on the focal pattern may have potential applications in micromanipulation, communication and other fields.

Visualization and Analysis of the Dynamic Assembly of a Heterologous Lantibiotic Biosynthesis Complex in Bacillus subtilis.

ABSTRACTA membrane-associated lanthipeptide synthetase complex, consisting of the dehydratase NisB, the cyclase NisC, and the ABC transporter NisT, has been described for nisin biosynthesis in the coccoid bacterium Lactococcus lactis. Here, we used advanced fluorescence microscopy to visualize the functional nisin biosynthesis machinery in rod-shaped cells and analyzed its spatial distribution and dynamics employing a platform we developed for heterologous production of nisin in Bacillus subtilis. We observed that NisT, as well as NisB and NisC, were all distributed in a punctate pattern along the cell periphery, opposed to the situation in coccoid cells. NisBTC proteins were found to be highly colocalized, being visualized at the same spots by dual fluorescence microscopy. In conjunction with the successful isolation of the biosynthetic complex NisBTC from the cell membrane, this corroborated that the visual bright foci were the sites for nisin maturation and transportation. A strategy of differential timing of expression was employed to demonstrate the in vivo dynamic assembly of NisBTC, revealing the recruitment by NisT of NisBC to the membrane. Additionally, by use of mutated proteins, the nucleotide binding domain (NBD) of NisT was found to function as a membrane anchor for NisB and/or NisC. We also show that the nisin biosynthesis sites are static and likely associated with proteins residing in lipid rafts. Based on these data, we propose a model for a three-phase production of modified precursor nisin in rod-shaped bacteria, presenting the assembly dynamics of NisBTC and emphasizing the crucial role of NisBC, next to NisT, in the process of precursor nisin translocation.

Physical Modeling of a Sliding Clamp Mechanism for the Spreading of ParB at Short Genomic Distance from Bacterial Centromere Sites.

SummaryBacterial ParB partitioning proteins involved in chromosomes and low-copy-number plasmid segregation are cytosine triphosphate (CTP)-dependent molecular switches. CTP-binding converts ParB dimers to DNA clamps, allowing unidimensional diffusion along the DNA. This sliding property has been proposed to explain the ParB spreading over large distances from parS centromere sites where ParB is specifically loaded. We modeled such a “clamping and sliding” mechanism as a typical reaction-diffusion system, compared it to the F plasmid ParB DNA binding pattern, and found that it can account neither for the long range of ParB binding to DNA nor for the rapid assembly kinetics observed in vivo after parS duplication. Also, it predicts a strong effect on the F plasmid ParB binding pattern from the presence of a roadblock that is not observed in ChIP-sequencing (ChIP-seq). We conclude that although “clamping and sliding” can occur at short distances from parS, another mechanism must apply for ParB recruitment at larger genomic distances.

IJU this issue

This issue contains 15 Original Articles, three of which are excellent prospective clinical trials, and one Urological Note. Cabozantinib is a multiple receptor tyrosine kinase inhibitor targeting MET (c-MET), VEGFR2, RET, AXL, KIT and TIE-2. In the phase III, randomized, open-label METEOR study, cabozantinib was associated with a significant progression-free survival benefit and a greater objective response rate versus everolimus in patients with metastatic renal cell carcinoma who had progressed after VEGFR-TKI. Tomita et al. (Niigata, Japan) carried out a bridging study to METEOR to evaluate the efficacy and safety of cabozantinib in Japanese patients. This phase II, open-label, single-arm study showed that cabozantinib provided clinical benefits in Japanese patients with renal cell carcinoma, with similar efficacy and safety to the non-Japanese population. Medical lasers are increasingly used to treat benign prostatic hyperplasia. Shoji et al. (Isehara, Japan) carried out a randomized prospective study to compare functional outcomes and complications over a period of 12 months in benign prostatic hyperplasia treated with thulium laser enucleation of the prostate or bipolar transurethral resection of the prostate. This study showed that thulium laser enucleation of the prostate is superior to bipolar transurethral resection of the prostate in resected volume, resected rates per prostate volume and transition zone volume, hemostasis, catheterization and hospitalization time, and decrease in prostate-specific antigen. However, excessive laser irradiation time in thulium laser enucleation of the prostate has the possibility to delay improvement of overactive bladder symptoms and decrease sexual function. Loose seeds and stranded seeds are available for low-dose rate brachytherapy. Each method has its own advantages and disadvantages, such as flexibility and fixation. Tanaka et al. (Kashihara, Japan) carried out a randomized controlled trial to compare the post-implant dosimetric parameters between the conventional method (using only the loose seeds) and the hybrid method. This study showed that the hybrid method of low-dose rate brachytherapy can achieve a higher coverage of the periprostatic region compared with the conventional method, while maintaining an acceptable level of urethral and rectal doses. The intravesical recurrence rate after transurethral resection of bladder tumor carried out for non-muscle-invasive bladder cancer (NMIBC) is high, and some risk factors for recurrence have been identified. Sazuka et al. (Chiba, Japan) evaluated the risk of the residual urine volume and preoperative pyuria in intravesical recurrence after transurethral resection of bladder tumor among NMIBC patients. They found that the presence of residual urine and pyuria raised the risk of intravesical recurrence after transurethral resection of bladder tumor for NMIBC. Furthermore, especially in men, the recurrence-free survival was significantly higher in patients without than with residual urine by propensity score matching analysis. Iwasawa et al. (Tokyo, Japan) investigated the relationship between fluid intake and tumor recurrence in NMIBC patients by using urine-specific gravity as an indicator of daily fluid intake. They found that high urine-specific gravity was associated with tumor recurrence, especially in patients not receiving adjuvant bacillus Calmette–Guérin therapy. This showed that increasing fluid intake might prevent recurrence in relatively low-risk NMIBC patients. Testicular microlithiasis (TM) is a relatively rare condition occurring in the testicular parenchyma that is characterized by multiple bright and small foci without acoustic shadow limited to the testicle on scrotal ultrasonography. TM is a characteristic of testicular dysgenesis syndrome and was shown to be associated with infertility. Hiramatsu et al. (Tokyo, Japan) evaluated the correlation between the degree of severity in TM and several factors. This study showed the prevalence of TM in normal healthy Japanese men who are trying for first-time pregnancy. This also showed that men with TM might have poor semen findings, and that men with severe TM might have even worse semen parameters. None declared.

Partial Nephrectomy For a Presumed Single Renal Mass Revealing Multiple Tumor Histologies: A Series of 4 Patients

Abstract Introduction/Objective Renal mass biopsy is known to have a low but unavoidable diagnostic error rate. However, the occurrence of multiple adjacent masses mimicking one mass clinically has been minimally studied. Methods We report a series of four patients who were radiologically presumed to have a single renal mass and treated with partial nephrectomy, yet who were found to have multiple demarcated renal cell carcinoma histologies at pathologic evaluation. Results All were men aged 63–70 years. Grossly, tumors were red brown with scant, bright yellow foci in one of them. Dominant tumors followed by smaller tumors were: patient 1 - clear cell renal cell carcinoma (5.0 cm), clear cell papillary renal cell carcinoma (0.5 cm), and papillary adenoma (0.6 cm); patient 2 - clear cell renal cell carcinoma (1.5 cm) and clear cell papillary renal cell carcinoma (0.5 cm); patient 3 - papillary renal cell carcinoma (5.0 cm) and eosinophilic variant of chromophobe renal cell carcinoma (1.0 cm); patient 4 - chromophobe renal cell carcinoma (4.0 cm) and clear cell papillary renal cell carcinoma (0.6 cm). Immunohistochemical studies for cytokeratin 7, carbonic anhydrase IX, high molecular weight cytokeratin, CD10, and alpha-methyl acyl-CoA racemase (AMACR) confirmed the separate components in all. Conclusion This series adds to the spectrum of causes that may contribute to discordant results of renal mass biopsy and resection specimens. Secondary smaller tumors appear to be predominantly nonaggressive histologies, enriched for clear cell papillary renal cell carcinoma. Pathologists and urologists should be aware of this occurrence when considering the role of renal mass biopsy and interpreting the results.

Visualization of Germination Proteins in Putative Bacillus cereus Germinosomes.

Bacillus cereus can survive in the form of spores for prolonged periods posing a serious problem for the manufacture of safe shelf-stable foods of optimal quality. Our study aims at increasing knowledge of B. cereus spores focusing primarily on germination mechanisms to develop novel milder food preservation strategies. Major features of B. cereus spores are a core with the genetic material encased by multiple protective layers, an important one being the spores′ inner membrane (IM), the location of many important germination proteins. To study mechanisms involved in germination of B. cereus spores, we have examined the organization of germinant receptors (GRs) in spores′ IM. Previous studies have indicated that in spores of B. cereus ATCC 14579 the L-alanine responsive GR, GerR, plays a major role in the germination process. In our study, the location of the GerR GR subunit, GerRB, in spores was examined as a C-terminal SGFP2 fusion protein expressed under the control of the gerR operon′s promoter. Our results showed that: (i) the fluorescence maxima and integrated intensity in spores with plasmid-borne expression of GerRB-SGFP2 were significantly higher than in wild-type spores; (ii) western blot analysis confirmed the expression of the GerRB-SGFP2 fusion protein in spores; and (iii) fluorescence microscopy visualized GerRB-SGFP2 specific bright foci in ~30% of individual dormant spores if only GerRB-SGFP2 was expressed, but, noticeably, in ~85% of spores upon co-expression with GerRA and GerRC. Our data corroborates the notion that co-expression of GR subunits improves their stability. Finally, all spores displayed bright fluorescent foci upon expression of GerD-mScarlet-I under the control of the gerD promoter. We termed all fluorescent foci observed germinosomes, the term used for the IM foci of GRs in Bacillus subtilis spores. Our data are the first evidence for the existence of germinosomes in B. cereus spores.

MON-459 Bilateral Killian-Jamieson Diverticulum Mimicking Thyroid Nodules

BackgroundIn recent years, incidence and prevalence of thyroid and extrathyroid lesion is increasing in the worldwide due to increase awareness of medical check-up, and widespread use of imaging techniques. A Killian Jamieson diverticulum (KJD), a rare type of hypopharyngeal pulsion diverticulum outpouching from the lateral wall of the proximal cervical esophagus, was incidentally detected and likely to be misinterpreted as a thyroid nodule while performing thyroid sonography. Clearly differentiate between those lesions is essential to avoid unnecessary invasive procedure. Here we report a typical case of bilateral Killian Jamieson diverticulum mimicking thyroid nodules.Clinical caseA 57-year-old Taiwanese man was referred to our endocrine outpatient department for further evaluation of thyroid nodules. The lesions were discovered while sonographic examination performed in the clinic for routine medical check-up. He denied having dysphagia, epigastric pain, odynophagia, halitosis, chronic cough or acid regurgitation, body weight loss, fever and dyspnea. He had no previous systemic disease and no prior radiation therapy. He lives in Nangang District, Taipei city. His body weight was 70 kg and BMI was 25. An examination of head and neck was unremarkable. Laboratory data revealed normal thyroid function (TSH: 0.67 uIU/ml; range 0.4~4.0, free T4: 0.83 ng/dl; range 0.9~1.8 and aTPO <1.0 IU/ml; range <5). Thyroid ultrasonography demonstrated oval, hypoechoic nodule-like lesions containing bright foci with acoustic shadow in the posterior aspect of the both lobes of thyroid gland. The rest of thyroid glands were normal appearance. An esophagography was performed and showed two contrast-filling anterior outpouching lesions at both sides of the cervical esophagus, around C7 level and both lesions were showing anterior outpouching appearance, consider Killian-Jamieson diverticulum. Taken together, he was diagnosed as KJD and clinical follow-up alone is suggested.Clinical lessonsKJD is usually incidentally detected and misdiagnosed as a thyroid nodule containing punctuate microcalcification foci as found in papillary thyroid carcinoma. To differentiate these nodules, real time sonographic examination is important. Although rare, non-thyroid lesions originating from the esophagus should be considered in the differential diagnosis of the thyroid nodules to avoid unnecessary invasive fine needle aspiration of thyroid gland.

Clustered telomeres in phase-separated nuclear condensates engage mitotic DNA synthesis through BLM and RAD52.

Alternative lengthening of telomeres (ALT) is a telomerase-independent telomere maintenance mechanism that occurs in a subset of cancers. One of the hallmarks of ALT cancer is the excessively clustered telomeres in promyelocytic leukemia (PML) bodies, represented as large bright telomere foci. Here, we present a model system that generates telomere clustering in nuclear polySUMO (small ubiquitin-like modification)/polySIM (SUMO-interacting motif) condensates, analogous to PML bodies, and thus artificially engineered ALT-associated PML body (APB)-like condensates in vivo. We observed that the ALT-like phenotypes (i.e., a small fraction of heterogeneous telomere lengths and formation of C circles) are rapidly induced by introducing the APB-like condensates together with BLM through its helicase domain, accompanied by ssDNA generation and RPA accumulation at telomeres. Moreover, these events lead to mitotic DNA synthesis (MiDAS) at telomeres mediated by RAD52 through its highly conserved N-terminal domain. We propose that the clustering of large amounts of telomeres in human cancers promotes ALT that is mediated by MiDAS, analogous to Saccharomyces cerevisiae type II ALT survivors.

Visualization of Germinosomes and the Inner Membrane in Bacillus subtilis Spores.

The small size of spores and the relatively low abundance of germination proteins, cause difficulties in their microscopic analyses using epifluorescence microscopy. Super-resolution three-dimensional Structured Illumination Microscopy (3D-SIM) is a promising tool to overcome this hurdle and reveal the molecular details of the process of germination of Bacillus subtilis (B. subtilis) spores. Here, we describe the use of a modified SIMcheck (ImageJ)-assistant 3D imaging process and fluorescent reporter proteins for SIM microscopy of B. subtilis spores' germinosomes, cluster(s) of germination proteins. We also present a (standard)3D-SIM imaging procedure for FM4-64 staining of B. subtilis spore membranes. By using these procedures, we obtained unsurpassed resolution for germinosome localization and show that >80% of B. subtilis KGB80 dormant spores obtained after sporulation on defined minimal MOPS medium have one or two GerD-GFP and GerKB-mCherry foci. Bright foci were also observed in FM4-64 stained spores' 3D-SIM images suggesting that inner membrane lipid domains of different fluidity likely exist. Further studies that use double labeling procedures with membrane dyes and germinosome reporter proteins to assess co-localization and thus get an optimal overview of the organization of Bacillus germination proteins in the inner spore membrane are possible.

Immediate-early gene Homer1a intranuclear transcription focus intensity as a measure of relative neural activation.

Immediate-early genes (IEGs) exhibit a rapid, transient transcription response to neuronal activation. Fluorescently labeled mRNA transcripts appear as bright intranuclear transcription foci (INF), which have been used as an all-or-nothing indicator of recent neuronal activity; however, it would be useful to know whether INF fluorescence can be used effectively to assess relative activations within a neural population. We quantified the Homer1a (H1a) response of hippocampal neurons to systematically varied numbers of exposures to the same places by inducing male Long-Evans rats to run laps around a track. Previous studies reveal relatively stable firing rates across laps on a familiar track. A strong linear trend (r2 > 0.9) in INF intensity was observed between 1 and 25 laps, after which INF intensity declined as a consequence of dispersion related to the greater elapsed time. When the integrated fluorescence of the entire nucleus was considered instead, the linear relationship extended to 50 laps. However, there was only an approximate doubling of H1a detected for this 50-fold variation in total spiking. Thus, the intranuclear H1a RNA fluorescent signal does provide a relative measure of how many times a set of neurons was activated over a ~10 min period, but the dynamic range and hence signal-to-noise ratios are poor. This low dynamic range may reflect previously reported reductions in the IEG response during repeated episodes of behavior over longer time scales. It remains to be determined how well the H1a signal reflects relative firing rates within a population of neurons in response to a single, discrete behavioral event.

Functioning of Fluorescent Proteins in Aggregates in Anthozoa Species and in Recombinant Artificial Models

Despite great advances in practical applications of fluorescent proteins (FPs), their natural function is poorly understood. FPs display complex spatio-temporal expression patterns in living Anthozoa coral polyps. Here we applied confocal microscopy, specifically, the fluorescence recovery after photobleaching (FRAP) technique to analyze intracellular localization and mobility of endogenous FPs in live tissues. We observed three distinct types of protein distributions in living tissues. One type of distribution, characteristic for Anemonia, Discosoma and Zoanthus, is free, highly mobile cytoplasmic localization. Another pattern is seen in FPs localized to numerous intracellular vesicles, observed in Clavularia. The third most intriguing type of intracellular localization is with respect to the spindle-shaped aggregates and lozenge crystals several micrometers in size observed in Zoanthus samples. No protein mobility within those structures was detected by FRAP. This finding encouraged us to develop artificial aggregating FPs. We constructed “trio-FPs” consisting of three tandem copies of tetrameric FPs and demonstrated that they form multiple bright foci upon expression in mammalian cells. High brightness of the aggregates is advantageous for early detection of weak promoter activities. Simultaneously, larger aggregates can induce significant cytostatic and cytotoxic effects and thus such tags are not suitable for long-term and high-level expression.

Abstract 3412: Functional knockout of ATRX or DAXX permits the alternative lengthening of telomeres (ALT) mechanism in prostate cancer cells

Abstract A key hallmark of cancer is unlimited replication, which requires cancer cells to evade replicative senescence induced by short telomeres. The majority of cancers overcome this critical replication barrier by upregulating the telomerase enzyme, a telomere-specific reverse transcriptase. However, a subset of cancers lack telomerase, and telomeres are maintained by employing the Alternative Lengthening of Telomeres (ALT) pathway, which is dependent on homologous recombination. Across a variety of tumor types, our laboratory and others have reported a robust correlation between ALT and recurrent cancer-associated somatic inactivating mutations in the ATRX-DAXX chromatin remodeling complex. In a previous comprehensive cancer survey of ALT, we reported that ALT was highly prevalent in some tumor types (e.g. astrocytomas, sarcomas, pancreatic neuroendocrine tumors), but we did not observe any ALT-positive primary prostate cancer (out of 1,176 analyzed). However, we subsequently found a subset of metastatic prostate cancers that harbor ALT, suggesting that mutations giving rise to ALT in this disease are unique to metastatic prostate cancer. Here, we have created the first prostate cancer cell lines exhibiting ALT, with the explicit purpose of molecularly characterizing ALT in prostate cancer and identifying promising therapeutic targets for men with ALT-positive lethal metastatic prostate cancer. Inactivating mutations in either ATRX or DAXX using the CRISPR/Cas9n system were introduced into the genetically well-characterized, telomerase-positive (ALT-negative) prostate cancer cell lines, LAPC-4 and CWR22Rv1. Resulting mutant subclones were compared to their parental (or empty vector) counterparts. In these new models, abolishing ATRX expression was sufficient to induce the ALT phenotype in both LAPC-4 and CWR22Rv1, as assessed by multiple biomarkers of ALT, including the presence of bright telomeric FISH foci, ALT-associated PML bodies (ABPs), and extrachromosomal telomere c-circles. Interestingly, abolishing DAXX expression induced ALT in only a subset (3/5) of LAPC-4 DAXX KO clones, and a subset (4/19) of CWR22Rv1 DAXX KO clones. We have successfully activated the ALT telomere maintenance phenotype in two prostate cancer cell lines through CRISPR-mediated targeted gene deletion. We are currently utilizing these isogenic cell lines to further characterize and elucidate the underlying biology of cancers harboring ALT, with the goal of pharmacologically targeting the molecular features unique to the ALT phenotype (e.g. ATR inhibition). The identification of ALT-specific drugs may pave the way for the development of new targeted treatments for the subset of men with ALT-positive lethal metastatic prostate cancer, and more broadly, other ALT-positive cancers. ALT is easily detected in clinical tissue samples, and thus would serve as a predictive biomarker for personalized medicine. Citation Format: Mindy K. Graham. Functional knockout of ATRX or DAXX permits the alternative lengthening of telomeres (ALT) mechanism in prostate cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3412. doi:10.1158/1538-7445.AM2017-3412

Pleural Effusions and Pneumothoraces.

1. Katherine Cashen, DO* 2. Tara L. Petersen, MD† 1. *Department of Pediatrics, Children's Hospital of Michigan/Wayne State University School of Medicine, Detroit, MI 2. †Division of Critical Care, Department of Pediatrics, The Children’s Hospital of Wisconsin/The Medical College of Wisconsin, Milwaukee, WI * Abbreviations: BTS: : British Thoracic Society CHF: : congestive heart failure CT: : computed tomography VATS: : video-assisted thoracoscopic surgery 1. Clinicians should be aware of the causes and clinical presentation of pleural effusions and pneumothoraces. 2. Clinicians should understand the current role of diagnostic tests, imaging modalities, and timing of minimally invasive treatments. After completing this article, readers should be able to: 1. Describe the pathogenesis of pleural fluid accumulation. 2. Identify the most likely causes of pleural effusion and pneumothorax. 3. Understand the basic clinical presentation, diagnostic tests, and management of pleural effusions and pneumothoraces. 4. Differentiate between transudative and exudative pleural effusions. 5. Understand the natural history of spontaneous pneumothorax. The pleural space is created by the parietal and visceral pleura that line the chest wall and the lung surface, respectively. Normally, only a small amount (0.3 mL/kg) of hypotonic fluid is present within the pleural space due to homeostatic balances in physiologic fluid production and absorption. Various infectious and noninfectious processes can lead to pathologic filling of the pleural space with fluid (effusion) or air (pneumothorax). Such pathologic changes create a true space that can interfere with normal lung mechanics and, in severe cases, cardiac function. Although much less common in pediatric than adult populations, pleural effusions and pneumothoraces in both groups can lead to substantial complications, resulting in significant morbidity and mortality if unrecognized or untreated. Overall, the cause of pleural effusions and pneumothoraces differs in children compared to adults. In adults, congestive heart failure (CHF) and malignancy account for a substantial number of pleural effusions, but these are uncommon causes in children. Infectious pleural effusions in the setting of pneumonia (parapneumonic effusions) remain the most common cause of effusions in both children and adults. Unlike the adult population, children experience spontaneous …

Abstract 4767: Generating and characterizing novel prostate cancer cell lines that employ the alternative lengthening of telomeres (ALT) telomere maintenance mechanism

Abstract A key hallmark of cancer is unlimited replication, which requires cancer cells to evade replicative senescence induced by telomere shortening. The majority of cancers overcome this critical barrier by up-regulating the enzyme telomerase, a telomere-specific reverse transcriptase. However, for a subset of cancers that lack telomerase, telomeres are maintained by employing the Alternative Lengthening of Telomeres (ALT) pathway, which is thought to be dependent on homologous recombination. In a variety of tumor types, our laboratory and others have reported a strong correlation between the ALT phenotype and recurrent cancer-associated somatic inactivating mutations ATRX or DAXX, genes encoding chromatin remodeling proteins. In a previous comprehensive survey of the ALT phenotype in cancer, we reported that the ALT phenotype is highly prevalent in some tumor types (e.g. astrocytoma, sarcomas, pancreatic neuroendocrine tumors), but we did not observe any ALT-positive cases in over 1,000 cases of primary prostate cancer. Notably, however, we found a subset of metastatic prostate cancer harbors the ALT phenotype, suggesting that mutations giving rise to ALT in this disease are unique to metastatic prostate cancer. Here, we have created the first prostate cancer cell lines exhibiting the ALT phenotype, with the purpose of molecularly characterizing ALT in prostate cancer and identifying promising therapeutic approaches for men with lethal metastatic prostate cancer harboring this phenotype. These novel cell lines were generated by inactivating ATRX using the CRISPR cas9 nickase system in a genetically well characterized prostate cancer cell line that normally expresses telomerase, as well as wild-type ATRX and DAXX. In this new model, abolishing ATRX expression is sufficient to induce the ALT phenotype, as assessed by multiple biomarkers of ALT, including bright telomeric FISH foci, ALT-associated PML bodies (ABPs), and c-circles. Interestingly, compared to the parental line, cells with compromised ATRX function have significantly lower telomerase activity and a five-fold decreased expression of telomerase reverse transcriptase (TERT). Ultimately, we will use these isogenic cell lines to further characterize and elucidate the basic biology of cancers harboring ALT, and pharmacologically target the molecular features unique to the ALT phenotype. The identification of ALT-specific drugs will pave the way for the development of new targeted treatments for a subset of men with lethal metastatic prostate cancer that harbor this unique molecular phenotype, and more broadly, other cancers that share the ALT phenotype in common. Citation Format: Mindy K. Graham, Jacqueline Brosnan-Cashman, Anthony Rizzo, Michael Haffner, Alan Meeker, Christopher Heaphy. Generating and characterizing novel prostate cancer cell lines that employ the alternative lengthening of telomeres (ALT) telomere maintenance mechanism. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4767.