Needle Tissue Research Articles

Winter Embolism and Recovery in the Conifer Shrub Pinus mugo L.

Research Highlights: Pronounced winter embolism and recovery were observed in the Alpine conifer shrub Pinus mugo L. Data indicated that the hydraulic courses and underlying mechanism were similar to timberline trees. Background and Objectives: At high elevation, plants above the snow cover are exposed to frost drought and temperature stress during winter. Previous studies demonstrated winter stress to induce low water potentials (Ψ) and significant xylem embolism (loss of conductivity, or LC) in evergreen conifer trees, and recovery from embolism in late winter. Here, we analyzed xylem hydraulics and related structural and cellular changes in a conifer shrub species. Materials and Methods: The uppermost branches of Pinus mugo shrubs growing at the Alpine timberline were harvested over one year, and the Ψ, water content, LC, proportion of aspirated pits, and carbohydrate contents were analyzed. Results: Minimum Ψ (−1.82 ± 0.04 MPa) and maximum LC (39.9% ± 14.5%) values were observed in mid and late winter, followed by a recovery phase. The proportion of aspirated pits was also highest in winter (64.7% ± 6.9% in earlywood, 27.0% ± 1.4% in latewood), and decreased in parallel with hydraulic recovery in late winter and spring. Glucose and fructose contents gradually decreased over the year, while starch contents (also microscopically visible as starch grains in needle and stem tissues) increased from May to July. Conclusions: The formation and recovery of embolism in Pinus mugo were similar to those of timberline trees, as were the underlying mechanisms, with pit aspiration enabling the isolation of embolized tracheids, and changes in carbohydrate contents indicating adjustments of osmotic driving forces for water re-distribution. The effects of future changes in snow cover regimes may have pronounced and complex effects on shrub-like growth forms, because a reduced snow cover may shorten the duration of frost drought, but expose the plants to increased temperature stress and impair recovery processes.

Simulating Ultrasound Tissue Deformation Using Inverse Mapping.

Ultrasound guidance is used for a variety of surgical needle insertion procedures, but there is currently no standard for the teaching of ultrasound skills. Recently, computer ultrasound simulation has been introduced as an alternative teaching method to traditional manikin and cadaver training because of its ability to provide diverse scenario training, quantitative feedback, and objective assessment. Current computer ultrasound training simulation is limited in its ability to image tissue deformation caused by needle insertions, even though tissue deformation identification is a critical skill in performing an ultrasound-guided needle insertion. To fill this need for improved simulation, a novel method of simulating ultrasound tissue-needle deformation is proposed and evaluated. First, a cadaver study is conducted to obtain ultrasound video of a peripheral nerve block. Then, optical flow analysis is conducted on this video to characterize the tissue movement due to the needle insertion. Tissue movement is characterized into three zones of motion: tissue near the needle being pulled, and zones above and below the needle where the tissue rolls. The rolling zones were centered 1.34 mm above and below the needle and 4.53 mm behind the needle. Using this characterization, a vector field is generated mimicking these zones. This vector field is then applied to an ultrasound image using inverse mapping to simulate tissue movement. The resulting simulation can be processed at 3.1 frames per second. This methodology can be applied through future optimized graphical processing to allow for accurate real time needle tissue simulation.

Fourier-transform infrared (FT-IR) spectroscopy analysis discriminates asymptomatic and symptomatic Norway spruce trees

Conifer trees, including Norway spruce, are threatened by fungi of the Heterobasidion annosum species complex, which severely affect timber quality and cause economic losses to forest owners. The timely detection of infected trees is complicated, as the pathogen resides within the heartwood and sapwood of infected trees. The presence of the disease and the extent of the wood decay often becomes evident only after tree felling. Fourier-transform infrared (FT-IR) spectroscopy is a potential method for non-destructive sample analysis that may be useful for identifying infected trees in this pathosystem. We performed FT-IR analysis of 18 phloem, 18 xylem, and 18 needle samples from asymptomatic and symptomatic Norway spruce trees. FT-IR spectra from 1066 – 912 cm−1 could be used to distinguish phloem, xylem, and needle tissue extracts. FT-IR spectra collected from xylem and needle extracts could also be used to discriminate between asymptomatic and symptomatic trees using spectral bands from 1657 – 994 cm−1 and 1104 – 994 cm−1, respectively. A partial least squares regression model predicted the concentration of condensed tannins, a defense-related compound, in phloem of asymptomatic and symptomatic trees. This work is the first to show that FT-IR spectroscopy can be used for the identification of Norway spruce trees naturally infected with Heterobasidion spp.

A MECHANICS-BASED MODEL FOR SIMULATING THE NEEDLE DEFLECTION IN TRANSVERSE ISOTROPIC TISSUE FOR A PERCUTANEOUS PUNCTURE

During the percutaneous puncture for robot-assisted brachytherapy, a medical needle is usually inserted into fiber-structured soft tissue which has transverse isotropic elasticity, such as muscle and skin, to deliver radioactive seeds that kill cancer cells. To place the radioactive seeds more accurately, it is necessary to assess the effect of the transverse isotropic elasticity on the needle deflection. A mechanics-based model for simulating the needle deflection in transverse isotropic tissue is developed in this paper. The anisotropic needle–tissue interaction forces are estimated and used as inputs to drive the model for simulating needle deflections for different insertion orientation angles. Automatic insertion experiments were performed on a single-layered porcine muscle at five different insertion orientation angles. The results show that the maximum difference in the tip deflection for the different insertion orientation angles is 2.99[Formula: see text]mm when the insertion depth is 50[Formula: see text]mm. The maximum simulated error of the needle axis deflection is 0.62[Formula: see text]mm for all insertion orientation angles. The developed model can successfully simulate the needle deflections inside transverse isotropic tissue for different insertion orientation angles. This work is useful for predicting and compensating for the deflection error for automatic needle insertion.

Distribution and diversity of bacterial endophytes from four Pinus species and their efficacy as biocontrol agents for devastating pine wood nematodes

In this study, we isolated a total of 238 culturable putative bacterial endophytes from four Pinus species (Pinus densiflora, P. koraiensis, P. rigida, and P. thunbergii) across 18 sampling sites in Korea. The samples were cultured in de Man Rogosa Sharpe and humic acid-vitamin agar media. These selective media were used to isolate lactic acid bacteria and Actinobacteria, respectively. Analysis using 16S ribosomal DNA sequencing grouped the isolated putative bacterial endophytes into 107 operational taxonomic units (OTUs) belonging to 48 genera. Gamma-proteobacteria were the most abundant bacteria in each sampling site and three tissues (needle, stem and root). The highest OTU richness and diversity indices were observed in the roots, followed by stem and needle tissues. Total metabolites extracted from three isolates (two isolates of Escherichia coli and Serratia marcescens) showed significant nematicidal activity against the pine wood nematode (Bursaphelenchus xylophilus). Our findings demonstrated the potential use of bacterial endophytes from pine trees as alternative biocontrol agents against pine wood nematodes.

Phylogenetic characterization of bacterial endophytes from four Pinus species and their nematicidal activity against the pine wood nematode

Recently, bacterial endophytes (BEs) have gained importance in the agricultural sector for their use as biocontrol agents to manage plant pathogens. Outbreak of the pine wilt disease (PWD) in Korea has led researchers to test the feasibility of BEs in controlling the pine wood nematode (PWN) Bursaphelenchus xylophilus. In this study, we have reported the diversity and biocontrol activity of BEs against the PWN. By employing a culture-dependent approach, 1,622 BEs were isolated from the needle, stem, and root tissues of P. densiflora, P. rigida, P. thunbergii, and P. koraiensis across 18 sampling sites in Korea. We classified 389 members based on 16S rDNA analysis and taxonomic binning, of which, 215 operational taxonomic units (OTUs) were determined. Using Shannon’s indices, diversity across the Pinus species and tissues was estimated to reveal the composition of BEs and their tissue-specific preferences. When their ethyl acetate crude extracts were analysed for biocontrol activity, 44 candidates with nematicidal activity were obtained. Among these, Stenotrophomonas and Bacillus sp. exhibited significant inhibitory activity against PWN during their developmental stages. Altogether, our study furnishes a basic comprehension of bacterial communities found in the Pinus species and highlights the potential of BEs as biocontrol agents to combat PWD.

A Reference Genome Sequence for the European Silver Fir (Abies alba Mill.): A Community-Generated Genomic Resource.

Silver fir (Abies alba Mill.) is a keystone conifer of European montane forest ecosystems that has experienced large fluctuations in population size during during the Quaternary and, more recently, due to land-use change. To forecast the species’ future distribution and survival, it is important to investigate the genetic basis of adaptation to environmental change, notably to extreme events. For this purpose, we here provide a first draft genome assembly and annotation of the silver fir genome, established through a community-based initiative. DNA obtained from haploid megagametophyte and diploid needle tissue was used to construct and sequence Illumina paired-end and mate-pair libraries, respectively, to high depth. The assembled A. alba genome sequence accounted for over 37 million scaffolds corresponding to 18.16 Gb, with a scaffold N50 of 14,051 bp. Despite the fragmented nature of the assembly, a total of 50,757 full-length genes were functionally annotated in the nuclear genome. The chloroplast genome was also assembled into a single scaffold (120,908 bp) that shows a high collinearity with both the A. koreana and A. sibirica complete chloroplast genomes. This first genome assembly of silver fir is an important genomic resource that is now publicly available in support of a new generation of research. By genome-enabling this important conifer, this resource will open the gate for new research and more precise genetic monitoring of European silver fir forests.

Can Copper Be Used to Treat Foliar Phytophthora Infections in Pinus radiata?

Red needle cast is a significant foliar disease of commercial stands of Pinus radiata caused by Phytophthora pluvialis in New Zealand. The effect of copper, applied as a foliar spray of cuprous oxide at a range of doses between 0 and 1.72 kg ha-1, was investigated in two controlled trials with potted plants and in an operational trial with mature P. radiata. In all trials, lesions formed on needles after artificial exposure to the infecting propagules (zoospores) of P. pluvialis were used to determine treatment efficacy, with the number and/or length of lesions as the dependent variable. Results across all trials indicated that cuprous oxide was highly effective at reducing infection of P. radiata with P. pluvialis. Application rates equivalent to ≥0.65 kg ha-1 significantly reduced infection levels relative to a control treatment, with foliar surface copper levels as low as 13 to 26 mg kg-1 of needle tissue preventing infection. Greater copper content was associated with a reduction in the proportion of needles with P. pluvialis lesions, with the probability of lesions developing decreasing approximately 1% for every 1 unit (in milligrams per kilogram) increase in copper content. Over a 90-day period, surface copper content declined to 30% of that originally applied, indicating an approximate period of treatment efficacy of 3 months. Our findings highlight the potential of cuprous oxide for the control of red needle cast in P. radiata stands. Further information about the optimal field dose, timing, and the frequency of foliar cuprous oxide application is key to prevent infection and also reduce the build up of inoculum during severe outbreaks of this pathogen.

Predicted functions, subcellular localizations, and expression patterns of genes encoding secretory proteins associated with pine pollen germination

Pollen germination represents the transition from mature to germinated pollen, which is a critical event in seed plant reproduction. Cell wall–related processes represent many of the cellular activities during this transition but information on the genes involved is limited, particularly in gymnosperms. Yeast secretion trap (YST) is employed in the current study to isolate cDNAs encoding secretory proteins associated with in vitro germinated pollen of loblolly pine (Pinus taeda). YST is a functional screen and when coupled with computational prediction provides insights on the diversity of populations, subcellular localizations, and functions of the encoded proteins. Based on 100 confirmed YST clones, our results identified 21 known, 4 unknown, and 10 hypothetical genes encoding secretory proteins, which are mostly predicted to be localized in the plasma membrane or extracellular space. Based on the known sequences, pollen germination involves genes associated with cell wall degradation, biosynthesis and remodeling, stress and defense responses, signaling, and protein processing. This study characterizes further 10 highly expressed cDNAs based on their temporal (mature pollen vs germinated pollen) and spatial (germinated pollen, young stem, and needle tissue) expression patterns, as well as sequence features such as the presence of transmembrane α-helix, glycosylphosphatidylinositol anchor, and conserved domains. It appears that pine pollen germination involves genes with static and dynamic expression profiles including those with germination-specific expressions. This study confirms the distinct expression profiles of mature and germinated pollen, and expands our understanding of the likely molecular players and processes associated with pine pollen germination, particularly pollen tube wall formation.

Influence of Microneedle Structure on Improving Skin Penetration

Because of the advantages of painless and minimally invasion, it has attracted more attention. The microneedle piercing the skin's stratum corneum to deliver drugs into the skin is considered as the optimal choice. The research and development on penetration skin are reviewed. The influence factors of piecing skin are discussed including Needle insertion phases, Piecing force during insertion and microneedle geometry. The interaction between microneedles and skin is affected by many parameters including needle geometry, tissue characteristics and insertional methods. The microneedle geometry is considered as one of the main factor of affecting whether the skin can be penetrated effectively or not.

Needle Insertion Control Method for Minimizing Both Deflection and Tissue Damage

Because fine needles can easily be deflected, accurate needle insertion is often difficult. Lower abdominal insertion is particularly difficult because of less imaging feedback; thus, an approach for allowing a straight insertion path by minimizing deflection is beneficial in cases of lower abdominal insertion. Although insertion with axial rotation can minimize deflection, the rotational insertion may cause tissue damage. Therefore, we established a novel insertion method for minimizing both deflection and tissue damage by combining rotation and vibration. Using layered tissues, we evaluated the effect of a combination of rotation and vibration in terms of deflection and tissue damage, which were measured by the insertion force and torque, and the area of the hole created by the needle using histological tissue sections to measure tissue damage. The experimental results demonstrated that insertion with unidirectional rotation is risky in terms of tissue wind-up, while insertion with bidirectional rotation can decrease deflection and avoid wind-up. We also found that insertion with vibration can decrease the insertion force and torque. Therefore, insertion with a combination of bidirectional rotation and vibration can minimize needle deflection and tissue damage, including the insertion force and torque and the hole area.

High Quality ATAC-Seq Data Recovered from Cryopreserved Breast Cell Lines and Tissue

DNA accessibility to transcription regulators varies between cells and modulates gene expression patterns. Several “open” chromatin profiling methods that provide valuable insight into the activity of these regulatory regions have been developed. However, their application to clinical samples has been limited despite the discovery that the Analysis of Transposase-Accessible Chromatin followed by sequencing (ATAC-seq) method can be performed using fewer cells than other techniques. Obtaining fresh rather than stored samples and a lack of adequate optimization and quality controls are major barriers to ATAC’s clinical implementation. Here, we describe an optimized ATAC protocol in which we varied nuclear preparation conditions and transposase concentrations and applied rigorous quality control measures before testing fresh, flash frozen, and cryopreserved breast cells and tissue. We obtained high quality data from small cell number. Furthermore, the genomic distribution of sequencing reads, their enrichment at transcription start sites, and transcription factor footprint analyses were similar between cryopreserved and fresh samples. This updated method is applicable to clinical samples, including cells from fine needle aspiration and tissues obtained via core needle biopsy or surgery. Chromatin accessibility analysis using patient samples will greatly expand the range of translational research and personalized medicine by identification of clinically-relevant epigenetic features.

Prospective Evaluation of Unprocessed Core Needle Biopsy DNA and RNA Yield from Lung, Liver, and Kidney Tumors: Implications for Cancer Genomics.

Context Targeted needle biopsies are increasingly performed for the genetic characterization of cancer. While the nucleic acid content of core needle biopsies after standard pathology processing (i.e., formalin fixation and paraffin embedding (FFPE)) has been previously reported, little is known about the potential yield for molecular analysis at the time of biopsy sample acquisition. Objectives Our objective was to improve the understanding of DNA and RNA yields from commonly used core needle biopsy techniques prior to sample processing. Methods We performed 552 ex vivo 18 and 20G core biopsies in the lungs, liver, and kidneys. DNA and RNA were extracted from fresh-frozen core samples and quantified for statistical comparisons based on needle gauge, biopsy site, and tissue type. Results Median tumor DNA yields from all 18G and 20G samples were 5880 ng and 2710 ng, respectively. Median tumor RNA yields from all 18G and 20G samples were 1100 ng and 230 ng, respectively. A wide range of DNA and RNA quantities (1060–13,390 ng and 370–6280 ng, respectively) were acquired. Median DNA and RNA yields from 18G needles were significantly greater than those from 20G needles across all organs (p < 0.001). Conclusions Core needle biopsy techniques for cancer diagnostics yield a broad range of DNA and RNA for molecular pathology, though quantities are greater than what has been reported for FFPE processed material. Since non-formalin-fixed DNA is advantageous for molecular studies, workflows that optimize core needle biopsy yield for molecular characterization should be explored.

Histologic Analysis of Endoscopic Ultrasound-Guided Through the Needle Microforceps Biopsies Accurately Identifies Mucinous Pancreas Cysts

It is a challenge to accurately assess pancreatic cystic lesions (PCLs) and determine their risk. We compared the yield of tissue acquired with endoscopic ultrasound (EUS)-guided microforceps (through the needle tissue biopsy [TTNB]) with that of samples collected by EUS-guided fine-needle-aspiration (EUS-FNA), and the accuracy of analyses of each sample type in the diagnosis of mucinous PCLs. We performed a prospective open-label study of 114 consecutive adults (56.1% women; mean age, 64.2 y) undergoing EUS-FNA evaluation of PCLs (mean size, 35 mm) at 7 centers, from June 20, 2016, through August 31, 2018. Samples were collected from each cyst by FNA and microforceps; samples collected by FNA were analyzed by cytology and samples collected by TTNB were analyzed by histology. Acquisition yield was defined as the percentage of specimens collected that were adequate for cytologic or histologic analysis. Diagnoses of mucinous cysts were made based on identification of pancreatic mucinous epithelium by cytology analysis of FNA samples or histologic analysis of TTNB samples. Surgical specimens were used as the reference standard when available. The EUS-guided microforceps were successfully inserted into 97.4% (111 of 114) of PCLs. Tissue acquisition yield was significantly higher with TTNB (95 of 114; 83.3%) than FNA (43 of 114; 37.7%) (P < .001). Sixty-one PCLs were determined to be mucinous based on TTNB analysis (53.5%) vs 11 with FNA analysis (9.6%) (P < .001). Among PCLs categorized as equivocal, based on the level of carcinoembryonic antigen, TTNB analysis found 50% (41 of 82) to be mucinous and FNA analysis found 8.5% (7 of 82) to be mucinous (P < .001). Findings from analyses of samples collected by TTNB were 100% concordant with findings from histologic analysis of surgical specimens (14 of 14), whereas only 3 of 14 findings from analysis of samples collected by FNA were in agreement with findings from surgical specimens (21.4%) (P < .001). Four of 5 mucinous PCLs with advanced neoplasia (80%) were detected with TTNB compared with none with FNA (P= .04). Self-limited intracystic bleeding occurred in 7 patients (6.1%), and acute pancreatitis in 6 patients (5.3%). In a multicenter prospective study of patients undergoing EUS-FNA for evaluation of PCLs, we found TTNB collection of tissues for histologic analysis to be safe and feasible, with an acquisition yield of 83.3%. Histologic analysis of samples collected by TTNB identified a larger proportion of mucinous PCLs compared with cytologic analysis of samples collected by FNA-even among samples categorized as equivocal, based on the level of carcinoembryonic antigen. More samples collected by TTNB than FNA were found to have advanced neoplasia. Clinicaltrials.gov no: NCT02979509.

Use of flow cytometry in the phenotypic diagnosis of hodgkin's lymphoma.

Hodgkin's lymphoma (HL) has a unique immunophenotype derived from immunohistochemistry (positive for CD15, CD30, and Pax-5; negative for CD3, CD20 in most cases, and CD45). The knowledge gained over recent years enables better diagnosis, prognosis, and treatment of HL. Flow cytometry as a tool for the diagnosis of classic HL has not been useful in the past due to the difficulty in isolating Reed-Sternberg cells as they are admixed in a rich inflammatory background which consists mainly of T cells, B cells, eosinophils, histiocytes, and plasma cells. However, in the recent past, several studies have tried to identify Reed-Sternberg cells using flow cytometry on fine needle aspiration or tissue biopsy of lymph nodes to confirm or supplement immunohistochemistry staining in diagnosis. Newer and more sensitive tools such as flow cytometry can be used for diagnosis, technology that may have been difficult in the past for diagnosis of this lymphoma subtype. Using flow cytometry, diagnosis is faster and could lead to point-of-care technology especially where we have typical immunophenotype signatures. © 2018 International Clinical Cytometry Society.

Development of nuclear microsatellite loci for Pinus albicaulis Engelm. (Pinaceae), a conifer of conservation concern.

Pinus albicaulis (whitebark pine) is a widely-distributed but rapidly declining high elevation western North American tree and a candidate for listing under the U.S. Endangered Species Act. Our objectives were to develop reliable nuclear microsatellite markers that can be used to assess within-population genetic diversity as well as seed and pollen migration dynamics, and to validate markers using two geographically proximal P. albicaulis populations. We identified 1,667 microsatellite-containing sequences from shotgun DNA libraries of P. albicaulis. Primer pairs were designed for 308 unique microsatellite-containing loci, and these were evaluated for PCR amplification success and segregation in a panel of diploid needle tissue. DNA was extracted with an SDS protocol, and primers were screened through gel electrophoresis. Microsatellites were genotyped through fluorescent primer fragment analysis. Ten novel and 13 transferred loci were found to be reproducible in analyses based on 20 foliage samples from each of two locations: Henderson Mountain, Custer Gallatin National Forest, Montana, and Mt. Washburn, Yellowstone National Park, Wyoming (USA). Transferred loci had higher numbers of alleles and expected heterozygosities than novel loci, but also revealed evidence for a higher frequency of null alleles. Eight of the 13 transferred loci deviated significantly from Hardy-Weinberg Equilibrium, and showed large positive FIS values that were likely inflated by null alleles. Mantel’s tests of transferred and novel markers showed no correlation between genetic and geographic distances within or among the two sampled populations. AMOVA suggests that 91% of genetic variability occurs within populations and 9% between the two populations. Studies assessing genetic diversity using these microsatellite loci can help guide future management and restoration activities for P. albicaulis.

Tissue-specific element profiles in Scots pine (Pinus sylvestris L.) needles

Key messageElement profile signatures of needle tissues differentiated four tissues: epidermis (main contributor: calcium), endodermis (main contributors: magnesium, sulphur and manganese), mesophyll (main contributor: potassium), and transfusion parenchyma (main contributor: zinc).Distribution of elements in cross-sections of Scots pine (Pinus sylvestris L.) needles was investigated using micro-proton-induced X-ray emission. Tissue-specific distributions of magnesium (Mg), sulphur (S), calcium (Ca), phosphorus (P), potassium (K), chlorine (Cl), manganese (Mn), iron (Fe), zinc (Zn), aluminium (Al) and silicon (Si) were resolved in a quantitative manner. Distribution maps and tissue-specific concentrations revealed the largest concentration of Ca in epidermis, of Mg, S and Mn in endodermis, of K in mesophyll and phloem and of Zn in transfusion parenchyma. Phosphorus, Cl, Fe, Al and Si did not exhibit apparent tissue-specific distribution. Inverse allocation of P and Ca was observed, a likely mechanism to prevent their precipitation. Taking the area of tissues into account, relative element distribution calculations indicated that mesophyll contained the majority of the elements studied, except Ca, which predominated in the epidermis (79% of total Ca concentration) and Mn, which predominated in the endodermis (40% of total Mn concentration). When considering a complete element profile of a particular tissue, four clusters were differentiated, which generally supported single-element observations. The first cluster differentiated mesophyll, xylem, phloem, transfusion tracheids and Strasburger cells with predominance of K, the second cluster differentiated epidermis on the basis of Ca, the third cluster differentiated endodermis with contributions from Mg, S and Mn, and the fourth cluster differentiated transfusion parenchyma with contribution from Zn. Information on tissue-specific-element allocations will complement structural and functional knowledge of needle tissues and advance our understanding of element/nutrient transfers in Scots pine.

Five-plane lancet needle design for soft PVC phantom tissue cutting

Lancet needle, having three planes at the tip to generate a sharp lancet point, is the most common needle tip geometry and used for medical procedures. This research presents two five-plane lancet needle designs, the five-plane lancet needle with two back bevels (FLN-B) and five-plane lancet needle with two front bevels (FLN-F), to study the effects of two additional bevel planes on the reduction of soft tissue cutting force. Mathematical models to calculate the inclination angle and rake angle along the cutting edges of FLN-B and FLN-F are developed. By using the grinding process, the prototype FLN-B and FLN-F needles are fabricated. And their inclination and rake angles along the cutting edges are investigated and compared to that of regular lancet needle. Needles insertion tests were conducted on soft PVC phantom which mimics the soft tissue. The initial peak insertion force and steady-state cutting force during needle insertion were identified, and the effect of cutting edge on needle soft tissue cutting force was studied. Compared to lancet needle, FLN-B and FLN-F both have higher inclination and rake angles at the tip cutting edge, could reduce the initial peak needle insertion force and tissue cutting forces, and thus can efficiently cut the soft tissue for medical applications.

Abstract 4098: New strategy of drug response assessment using PDX organoid platform for non-resectable pancreatic cancer

Abstract To develop an efficient drug screening platform which overcomes the difference of drug response between initial screening and clinical trial stage is a pivotal issue for drug discovery. The patient-derived Xenograft (PDX) model has been reported as a screening system to reflect the microenvironment and heterogeneity of tumor. However, in pancreatic cancer that 80 % of patients is non-resectable, PDX is not be suitable for an initial screening model in terms of economic- and time cost of mouse-based amplification system as well as the lack of obtaining pancreatic tumor tissue from fine needle biopsy or percutaneous gun. To overcome this limitation, here we newly suggested organoids system, miniature organ culture on a dish, that are generated from tumor tissues of orthotopic PDX model, which has the advantages of reflection of each patient's characteristics as well as amplification of limited tumor tissue. Besides, it is possible to screen of drug responsibility with a little number of cells. 12 organoids derived from PDX using needle or gun biopsy tumor tissues showed EpCAM overexpression and each unique morphological phenotype. Moreover, from drug responsibility test, H #43 and H #44, an organoids derived from a gemcitabine-sensitive patients, were highly responsible to gemcitabine, whereas the organoids from gemcitabine-resistant patients, G #20 and H #19 showed a strong resistance to gemcitabine as measuring the IC50 value. In addition, combined treatment with gemcitabine and abraxane to the G #13 model which has no clinical information of drug response due to early death, it inhibited organoid formation significantly, showing a combination index below 1, which was proved through in vivo (PDX) validation. Taken together, the PDX-Organoid system might be able to reflect primary tumor characteristics as well as to overcome the quantitative limitations of the specimen and time cost, and thereby it is possible to predict drug response early in vitro, making it very efficient as an anti-cancer drug development platform for pancreatic cancer. Citation Format: A-Ra Jeon, Sun Il Choi, Sang-Jae Park, Sung-Sik Han, Sun-Young Kong, Min Kyeong Kim, Yu-sun Lee, Jieun Im, Min Kyeong Lee, Sang Hyun Park, Joon-Ki Kim, Kyong-Ah Yoon, Young-Hwan Koh, Ju Hee Lee, Woo Jin Lee, Sang Myung Woo, Yun-Hee Kim. New strategy of drug response assessment using PDX organoid platform for non-resectable pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4098.

Mo1361 NOVEL FINE NEEDLE BIOPSY NEEDLE SIGNIFICANTLY DECREASES NUMBER OF NEEDLE PASSES AND PROCEDURAL TIME IN PATIENTS WITH PANCCREATIC CANCER UNDERGOING INDEX DIAGNOSTIC ENDOSCOPIC ULTRASOUND

Endoscopic ultrasound(EUS) guided fine needle tissue sampling can be done using fine-needle aspiration(FNA) or fine-needle biopsy (FNB) needles. A novel FNB SharkCore(Medtronic, Dublin, Ireland) needle (FNB-SC) has been shown to achieve good diagnostic yield with fewer number of needle passes. The aim of this study was to compare diagnostic yield and procedure time for EUS performed using either traditional FNA needle or the FNB-SC needle in patients with pancreatic cancer (PC). All patients referred to our institute (10/2014-11/2017) for EUS of pancreatic mass and eventually diagnosed with pancreatic cancer (PC) were included in the study. Patient with any other diagnosis were excluded. If patient required more than 1 EUS at our center for diagnosis,data from only the index-EUS was used for analysis. Patients referred after failed EUS at outside facilities (n=1) or cases where multiple needles (n=5) were used were excluded. All but 1 case (was excluded) were done using either FNA-BS22G or FNA-BS25G [Expect needle; Boston Scientific] or FNB-SC22G needle. Data regarding patient demographics, lesion location, technical details of procedure, procedure time and diagnostic yield was obtained from the electronic health records. Procedure time was defined as time from insertion to final removal of EUS scope from patient. During study period, 77 patients referred for EUS of pancreatic masses were diagnosed with PC. Seven patients were excluded and remaining 70 patients were grouped based on type of needle used –FNA-BS22 needle (n=24), FNA-BS25 (n=22) and FNB-SC22 (n=24). All groups were comparable in demographics. Successful diagnosis of PC was made in 100% patients with FNA-BS22, 91% patients with FNA-BS25G and 92% patients with FNB-SC22 needle. These differences were not statistically significant. The median (IQR) number of needle-passes per EUS were 5[4-6] for FNA-BS22, 4[4-5] for FNA-BS25 and 2[2-2] for FNB-SC22. These difference were not significantly different between the two FNA-BS sub-groups(p=0.08). However there was statistically significant difference between FNB-SC22 and FNA-BS22(p<0.001) and between FNB-SC22 and FNA-BS25 (p<0.0001).The median (IQR) procedure time was 44(37.5-59) min for FNA-BS22, 37.5(32-51) min for FNA- BS25 and 25(19-37.5) min for FNB-SC22 needle.Procedure time was not significantly different between the two FNA-BS groups (p=0.3). However, the difference in procedure time (25 minutes,20-37) min for FNB-SC22 was statistically significant compared to FNA-BS22(p<0.0001), and FNA-BS25(p<0.004). Although currently available FNA and FNB needles are comparable in achieving high diagnostic yield in patients with pancreatic cancer, the novel FNB-SC 22G needle requires fewer needles passes to achieve this high diagnostic yield and dramatically decreases procedural time.