Needle Characteristics Research Articles

Abstract P2-08-53: Tumor elasticity and clinicopathologic factors affecting neoadjuvant chemotherapy response in breast cancer patients

Abstract Background: Neoadjuvant chemotherapy for breast cancer has been increased. Many studies have reported on clinicopathologic factors to predict neoadjuvant chemotherapy response. Elastography, which is usually used to differentiate benign and malignant tumors, can be performed to evaluate tissue elasticity during conventional ultrasonography. The purpose of this study was to determine the clinicopathologic factors, including tumor elasticity, that affect neoadjuvant chemotherapy response in stage II or III breast cancer patients. Methods: From April 2014 to March 2017, 95 patients received neoadjuvant chemotherapy for clinical stage IIa-IIIc primary breast cancer. To evaluate tumor elasticity, strain elastography was performed in 74 patients before neoadjuvant chemotherapy. Patients were divided into two groups by the Tsukuba elasticity scoring system (soft group ≤3 vs. hard group ≥4). Histologic type, nuclear grade, tumor infiltrating lymphocytes (TILs), tumor cellularity, characteristics of stroma, and hormone receptor (HR) and human epidermal growth factor receptor 2 (HER2) status were evaluated using core needle biopsy specimens obtained before neoadjuvant chemotherapy. Pathologic complete response (pCR) was defined as the absence of invasive carcinoma in breast (ypT0 and ypTis) and axillary lymph node (ypN0). Residual cancer burden (RCB) was also calculated in 79 cases and the cases were categorized into 2 groups; favorable RCB group (RCB-0 and I) and unfavorable RCB group (RCB-II and III). Results: The mean age of patients was 46.43±8.62 years (range, 27-71 years) and the mean initial tumor size was 3.63±1.95cm (range, 2.1-12.8cm). Twenty-four patients (32.4%) were categorized into the soft group and 50 patients (67.6%) into the hard group. The mean tumor cellularity on core needle biopsy specimens and characteristics of stroma were not significantly different between the two groups (p=0.35 and p=0.79, respectively). Twenty-two patients achieved pCR (23.2%). The patients with pCR were more likely to have estrogen receptor (ER) or progesterone receptor (PR) negative breast cancer (p=0.04 and p=0.03). The rate of nuclear grade 3 was higher in patients with pCR than those without (p=0.03). Tumor elasticity was not correlated with pCR (p=0.28). Thirty patients (38.0%) achieved favorable RCB and forty-nine patients (62.0%) had unfavorable RCB. Not only the rates of ER negativity (p=0.05), PR negativity (p=0.03), nuclear grade 3 (p=0.01), and high TILs level (≥ 10%) (p=0.04) but also the mean TILs level (p=0.05) were significantly higher in the favorable RCB group compared withthe unfavorable RCB group. No significant difference in tumor elasticity was observed between the two groups (p=0.30). In univariate analyses, nuclear grade 3 (p=0.03), and high TILs level (≥10%) (p=0.04) were significantly correlated with favorable RCB. HR negativity was an independent predictor of favorable RCB in multivariate analysis (odds ratio, 2.93; 95% confidence interval, 1.04-8.28; p=0.04). Conclusion: Tumor elasticity was not associated with pCR or RCB. HR negativity was an independent predictor for favorable RCB.Nuclear grade and TILs were also potential predictive factors for neoadjuvant chemotherapy response. Citation Format: Park JY, Choi JE, Bae YK, Lee SJ. Tumor elasticity and clinicopathologic factors affecting neoadjuvant chemotherapy response in breast cancer patients [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-08-53.

Influence of growing conditions on morphological and anatomical characteristics of pine needles in the northern taiga

The aim of the study was to determine the adaptive characteristics of pine needles associated with age and different growing conditions. The length of the needles decreases and its variability reduces with increasing dryness and poverty of the soil. In oppressed trees, the coefficient of variability of the length of the needles on the tree is 8%. The coefficient of variation in the length of needles approaching 20% will indicate the best conditions for the growth of a particular tree. Trends of the dependence of width and thickness of needles on growing conditions were not identified. The area of needles in pine forests with optimal water regime of soils (blueberry, cowberry type) varies in the range of 112–124 mm<sup>2</sup>. In extreme growing conditions pine needles area is reduced by 27–33% and equals 76–86 mm<sup>2</sup>. These ranges of values of the areas of needles are typical for plantings of the third and fourth classes of age. Changing the width and thickness of the needles is aimed at compensating for changes in the length of the needles in the direction of maintaining the optimal area for these conditions needles. In extreme conditions, the area of the assimilating tissue increases, and the area of the conducting tissue (stele) decreases. Correlation dependences of the area of the stele of needles with the cross-sectional area, with the area of conducting beams, with the number of resin canals and with the cover fabric are revealed.

Influence of the Needle Number on the Heat Insulation Performance of Pre-oxidized Fibre Felts

Many factors were needed to be considered to prepare pre-oxidised fibre felts with excellent heat insulation performance, and different production processes showed differences in the heat insulation performance of pre-oxidised fibre felts. In order to probe into the influence of the production process on the heat insulation performance of materials, a large number of experiments were needed to be carried out. For needle-punched nonwoven pre-oxidised fibre felts, web features, needle characteristics and the needle process will all affect the structure of pre-oxidised fibre felts, thus bringing a major influence on the heat insulation performance of pre-oxidised fibre felts. In this paper, the influence of the needle number on the heat insulation performance of pre-oxidised fibre felts was mainly studied. Results showed that an increase in the needle number will cause a decrease in the thickness and gram weight of pre-oxidised fibre felts, and a weakening trend in the heat insulation performance of pre-oxidiaed fibre felts with an increasing needle number at room temperature and at 100-200 °C was shown. Moreover when the needle number was 1 and 2, the pre-oxidised fibre needled felts had good heat insulation performance, and for pre-oxidized fibre felts at different needle numbers with increasing temperature, the temperature difference in a steady state increased linearly.

Environmental contribution to needle variation among natural populations of Pinus tabuliformis

Variations in the phenotypic characteristics of conifer needles is a consequence of genetic evolution that has been widely used in geographic variation and ecological studies. Although many studies are based on an in situ sampling strategy and generally realize the contribution of environmental effects to variation in needle traits, it is still uncertain which needle traits are most influenced by genetic effects and which are most influenced by the environment. Using both a common garden experiment to eliminate environmental heterogeneity and an in situ sampling strategy, we compared 18 Pinus tabuliformis needle traits among 10 geographical populations. Using both sampling strategies, we found significant differences in needle traits among populations and among individuals within populations. Differences in the “among-population” variance component between the two sampling strategies revealed the environmental contribution among natural populations for each trait. The among-population variance in the following traits exceeded 8%: needle length, number of stomata within 2 mm (NS2), number of stomatal lines on the planar side, number of resin canals (RCN) and the resin canal area (RCA). For the stability of needle traits, NS2, RCN, RCA, ratio of the vascular bundle area to the RCA (VBA/RCA), and MA/RCA differed significantly in more than five provenance changes between the common garden populations and natural populations, which may be susceptible to environmental effects. Conversely, the cross-sectional area, mesophyll area (MA), MA/(VBA + RCA), and MA/VBA were phenotypically stable. Geographic variation patterns and systematic relation of needle traits differed between the two sampling strategies, suggesting that in situ sampling results may reflect environmental effects and deviate statistical parameters for genetic study. Future studies of genetic evolution in the context of geographic variation should be based on appropriate sampling strategies and stable phenotypic traits.

How Placebo Needles Differ From Placebo Pills?

Because acupuncture treatment is defined by the process of needles penetrating the body, placebo needles were originally developed with non-penetrating mechanisms. However, whether placebo needles are valid controls in acupuncture research is subject of an ongoing debate. The present review provides an overview of the characteristics of placebo needles and how they differ from placebo pills in two aspects: (1) physiological response and (2) blinding efficacy. We argue that placebo needles elicit physiological responses similar to real acupuncture and therefore provide similar clinical efficacy. We also demonstrate that this efficacy is further supported by ineffective blinding (even in acupuncture-naïve patients) which may lead to opposite guesses that will further enhances efficacy, as compared to no-treatment, e.g., with waiting list controls. Additionally, the manner in which placebo needles can exhibit therapeutic effects relative to placebo pills include enhanced touch sensations, direct stimulation of the somatosensory system and activation of multiple brain systems. We finally discuss alternative control strategies for the placebo effects in acupuncture therapy.

Microscopic and molecular identification of pine needles

To identify pine needles from different plant origins by microscopic and molecular approaches. The characteristics of pine needles of Pinus massoniana Lamb., Pinus thunbergii Parl. and Pinus armandii Franch. were investigated via plant morphology and microscopic characteristics. ITS2 and rbcL were analyzed with PCR amplification and bi-directional sequencing. MEGA 6.0 was used to calculate the intra-and inter-specific Kimura-2-Parameter (K2P) distances, and the phylogenetic tree was constructed by using the neighbor-joining (NJ) method. There were significant differences in the number and length of pine needles, number of vascular bundles, distribution of stomatal lines, number and distribution of resin channels among three kinds of pine needles. The lengths of ITS2 sequences of Pinus massoniana Lamb., Pinus thunbergii Parl. and Pinus armandii Franch. were 470, 469 and 470 bp, respectively. The lengths of rbcL sequences in three kinds of pine needles were 553 bp. The intraspecific variation rates of ITS2 sequences in Pinus massoniana Lamb., Pinus thunbergii Parl. and Pinus armandii Franch. were 0%, 0.2%, and 2.8%, respectively; and the intraspecific variation rates of rbcL sequences were 0%, 2.4%, and 1.1%, respectively. There was no significant barcoding gap in intraspecific and interspecific genetic distances of ITS2 sequences. The intraspecific and interspecific distances of rbcL sequences were clearly separated in the barcoding gap test. The NJ tree based on rbcL showed that the three pine needles clustered into three separate groups, indicating that rbcL DNA marker could distinguish the Pinus massoniana Lamb., Pinus thunbergii Parl., Pinus armandii Franch. and its close relative species. s The three types of pine needles can be distinguished accurately and rapidly by microscopic and molecular identification. The study provides methodology and experimental basis for the quality evaluation and classification of pine needles.

The Impact of Spinal Needle Selection on Postdural Puncture Headache: A Meta-Analysis and Metaregression of Randomized Studies.

Potentially broadened indications for spinal anesthesia require increased understanding of the risk factors and prevention measures associated with postdural puncture headache (PDPH). This review is designed to examine the association between spinal needle characteristics and incidence of PDPH. Meta-analysis and metaregression was performed on randomized controlled trials to determine the effect of needle design and gauge on the incidence of PDPH after controlling for patient confounders such as age, sex, and year of publication. Fifty-seven randomized controlled trials (n = 16416) were included in our analysis, of which 32 compared pencil-point design with cutting-needle design and 25 compared individual gauges of similar design. Pencil-point design was associated with a statistically significant reduction in incidence of PDPH (risk ratio, 0.41; 95% confidence interval, 0.31-0.54; P < 0.001; I = 29%) compared with cutting needles among studies that assessed both design types. Subgroup analysis among obstetric and nonobstetric procedures yielded similar results. After adjustment for significant covariates, metaregression analysis among all 57 included trials revealed a significant correlation between needle gauge and rate of PDPH among cutting needles (slope = -2.65, P < 0.001), but not pencil-point needles (slope = -0.01, P = 0.819). Pencil-point needles are associated with significantly lower incidence of PDPH compared with the cutting-needle design. Whereas a significant relationship was noted between needle gauge and PDPH for cutting-needle design, a similar association was not shown for pencil-point needles. Providers may consider selection of larger-caliber pencil-point needle to maximize technical proficiency without expensing increased rates of PDPH.

Taxonomic and geographic differentiation of Juniperus phoenicea agg. based on cone, seed, and needle characteristics

The aim of this study was to examine the diversity of, and differentiation between, 41 natural populations representing Juniperus phoenicea complex within their geographic range using the morphological characteristics of cones, seeds, and sprouts with leaves. Seven populations of J. phoenicea s.s., 25 J. turbinata and nine J. canariensis, each represented by ∼20–30 individuals, were studied. The characteristics describing the size of cones and seeds and their proportions were different between J. phoenicea s.s., J. turbinata, and J. canariensis, and were useful in distinguishing between these three taxa. The populations of J. canariensis had a significantly higher percentage of trimerous cones, a higher number of cone scales, but a lower number of seeds, which were also larger than the seeds from other taxa. Juniperus phoenicea s.s., J. turbinata, and J. canariensis revealed a high level of multivariate differentiation, but there were no single characteristics which allowed one to distinguish between these alone. We detected significant differences between populations of J. turbinata from Europe and Africa, which supports the role of the Gibraltar Straight in the structuring of conifer species. Significant differences were also detected between European and Asiatic populations in several characters examined, indicating the important role of the Aegean Sea in the structuring of this taxon.

Mechanical Shaking and Baling of Balsam Fir Trees Influence Postharvest Needle Senescence and Abscission

This study investigated the influence of both shaking duration and number of trees per bale on postharvest needle characteristics such as percentage needle loss, needle retention duration and explored the physiological roles of endogenous ethylene and volatile terpene compounds (VTCs). To accomplish these objectives, 25 six-year-old trees were detached and exposed to a range of shaking durations (0 to 60 sec.), and 30 six-year-old detached trees were exposed to baling treatments from 0 to 5 trees. Response variables measured were percent needle loss, needle retention duration, average water use, ethylene and volatile terpene compound evolution. Trees shaken for 60 seconds lost 16% less needle compared to control, which was consistent with the decrease in percent needle loss with increasing shaking duration. Baled trees lost 13% more needles compared to control, but percent needle loss was observed to decrease with increasing number of trees in a bale. These trends corresponded with increasing ethylene and VTC evolutions, where the longer the shaking duration or larger number of trees in a bale, the higher the ethylene and VTC evolutions. One can therefore draw inference that mechanical perturbation as a result of shaking and baling induce biosynthesis and regulation of ethylene and VTC in balsam fir trees in an effort to regulate postharvest needle abscission.

Loss of flexion during bronchoscopy: a physical experiment and case study of commercially available systems.

During routine endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) procedures, especially with biopsy of lymph nodes in or around the left upper lobe, frequent reports have noted the loss of ultrasound image and needle angulation leading to an inability to biopsy nodes visualised by EBUS. The aim of this research was to investigate and compare this loss of angulation with commercially available scopes. Bench-top experiments and a clinical case study demonstrated the varying loss of scope angulation, flexibility and manoeuvrability with different scopes and biopsy instruments leading to procedural implications. Improvements in both the EBUS scope and needle characteristics are required to overcome this limitation which has implications in bronchoscope navigation and the diagnostic yield of EBUS-TBNA.

Relationships among Abies nebrodensis, A. alba and A. cephalonica in the morphological and anatomical needle characteristics

We used 39 morphological and anatomical needle traits in the biometric comparisons Abies nebrodensis with A. alba and A. cephalonica. The multivariate analyses were utilised and a closer relationship of A. nebrodensis to A. cephalonica than to A. alba was detected, in contrast to what has been shown for cone characteristics.

Comparison of range-wide chloroplast microsatellite and needle trait variation patterns in Pinus mugo Turra (dwarf mountain pine)

In this study, range-wide genetic variation was analysed in 553 Pinus mugo Turra (dwarf mountain pine) individuals from 21 locations using 11 chloroplast microsatellites. Our main goal was to assess the spatial distribution of neutral genetic variation. We also used data from a previous study on the morphological variation of needles from 18 stands of P. mugo. In total, 22 needle characteristics were reanalysed and compared to microsatellite data to describe the distribution of morphological variation in the context of neutral genetic variation. We hypothesised that the chloroplast microsatellite and needle trait variation patterns would not entirely overlap. The results indicate the recent divergence of P. mugo populations derived from a formerly larger distribution. We identified 4 genetic and 3 morphological clusters whose spatial distribution overlapped only to some extent. The distribution of genetic variation showed a south-north pattern with signs of admixture in the Alps and Carpathians. Two south-westernmost stands from Italy were evidently isolated from the others. In contrast, morphological variation tended to display a west-east pattern. A separate group based on needle traits was formed mostly by eastern stands and was not observed by microsatellite analysis. In addition, a few needle characteristics significantly correlated with longitude and climate variables. These findings suggest that eastern populations of P. mugo may be of different origin and/or that some needle characteristics may be adaptively important in these locations. The potential roles of past demographic events, phenotypic plasticity and local adaptation in shaping the patterns of genetic and morphological variation in P. mugo are discussed.

Effect of spinal needle characteristics on measurement of spinal canal opening pressure

ObjectiveA wide variety of spinal needles are used in clinical practice. Little is currently known regarding the impact of needle length, gauge, and tip type on the needle's ability to measure spinal canal opening pressure. This study aimed to investigate the relationship between these factors and the opening-pressure measurement or time to obtain an opening pressure. MethodsThirteen distinct spinal needles, chosen to isolate the effects of length, gauge, and needle-point type, were prospectively tested on a lumbar puncture simulator. The key outcomes were the opening-pressure measurement and the time required to obtain that measure. Pressures were recorded at 10-s intervals until 3 consecutive, identical readings were observed. ResultsTime to measure opening pressure increased with increasing spinal needle length, increasing gauge, and the Quincke-type (cutting) point (P<0.001 for all). The time to measurement ranged from 30s to 530s, yet all needle types were able to obtain a consistent opening pressure measure. ConclusionAlthough opening pressure estimates are unlikely to vary markedly by needle type, the time required to obtain the measurement increased with increasing needle length and gauge and with Quincke-type needles.

Effect of Artificially Induced Drought Stress on Seedlings of Pinus roxburghii Sarg

ABSTRACT Water relation and growth parameters of drought stressed seedlings of Chir pine (Pinus roxburghii Sarg.) were studied over a one year period. The seedlings were subjected to three drought cycles of 9, 18, 27 days and one control level (watered every alternate day) in a polyhouse. Pre-dawn (5.30-6.30 AM) and Mid-day water potential was estimated using a pressure chamber. The bench drying method was followed for developing P-V curves for estimating components of water potential. Osmotic adjustment was estimated as the difference between the osmotic potential at zero and full turgor of seedlings kept at control and those given 27 days drought. Across drought cycles the pre- dawn water potential ranged between -0.59 MPa and -2.12 MPa and the mid-day water potentials were always lower than pre-dawn water potentials. The Osmotic adjustment was – 1.17 MPa at full turgor and -2.0 MPa at zero turgor. The seedlings growth was positively related to soil moisture and water potential. The daily change in water potential (difference between pre-dawn and mid-day water potential) declined with increasing drought and was nominal (less than -0.2 MPa) in seedlings subjected to 18 and 27 days drought cycle. Needle characteristics were severely affected by water stress. In Pinus roxburghii Sarg seedlings osmotic adjustment may be an important adaptive mechanism that assists it to invade and grow on dry inhospitable sites.

Variability of morphometrical characteristics of needles at a clonal plantation of plus trees of scots pine (Pinus sylvestris L.)

The formation of plus trees assortment for seed orchards is one of the most difficult problems of contemporary forest breeding. This problem is related to the risk of inbreeding depression of the seed progeny of plus trees, which do not have any defense mechanism against self-pollination. Economically, the Scots pine is one of the most important wood species. Diverse characteristics of its needles make a subject for multidisciplinary research. Needle size is accepted as an indirect indicator of growth pine energy. Our research was focused on selection valuation of Scots pine plus trees by morphometric features of needles. Plus trees are represented by their clones in first-order seed orchards in the Nizhny Novgorod region. When collecting the source material, the elimination of differentiating effects of environmental factors and time factors was ensured. The dissimilarity of plus trees at a wide range of signs was manifested to different degrees. Because the heterogeneity of the assortment composition of the seed orchard in question was formed against the background of the aligned environmental conditions, there was every reason to consider it as being caused largely by hereditary factors. It was confirmed by the results of ANOVA. The predominant influence of distinctions between ortets was established. The influence of distinctions between the ramets was revealed – that was comparable to the residual variance. Pronounced heterogeneity of the composition and its genetic determinism set up conditions for effective multivariate comparisons of plus trees. Factor analysis formed its integrated independent variables from a common set of morphological parameters of needles. They are used in cluster analysis along with the original signs. Cluster analysis revealed in the seed orchards plus trees that are to the greatest extent different from the others. They can be combined with all the other plus trees in cross-breeding schemes to achieve the heterosis effect and to eliminate the risk of inbreeding depression.

Consensus guidelines for lumbar puncture in patients with neurological diseases

IntroductionCerebrospinal fluid collection by lumbar puncture (LP) is performed in the diagnostic workup of several neurological brain diseases. Reluctance to perform the procedure is among others due to a lack of standards and guidelines to minimize the risk of complications, such as post-LP headache or back pain. MethodsWe provide consensus guidelines for the LP procedure to minimize the risk of complications. The recommendations are based on (1) data from a large multicenter LP feasibility study (evidence level II-2), (2) systematic literature review on LP needle characteristics and post-LP complications (evidence level II-2), (3) discussion of best practice within the Joint Programme Neurodegenerative Disease Research Biomarkers for Alzheimer's disease and Parkinson's Disease and Biomarkers for Multiple Sclerosis consortia (evidence level III). ResultsOur consensus guidelines address contraindications, as well as patient-related and procedure-related risk factors that can influence the development of post-LP complications. DiscussionWhen an LP is performed correctly, the procedure is well tolerated and accepted with a low complication rate.

Single Crystal Diamond Needle as Point Electron Source.

Diamond has been considered to be one of the most attractive materials for cold-cathode applications during past two decades. However, its real application is hampered by the necessity to provide appropriate amount and transport of electrons to emitter surface which is usually achieved by using nanometer size or highly defective crystallites having much lower physical characteristics than the ideal diamond. Here, for the first time the use of single crystal diamond emitter with high aspect ratio as a point electron source is reported. Single crystal diamond needles were obtained by selective oxidation of polycrystalline diamond films produced by plasma enhanced chemical vapor deposition. Field emission currents and total electron energy distributions were measured for individual diamond needles as functions of extraction voltage and temperature. The needles demonstrate current saturation phenomenon and sensitivity of emission to temperature. The analysis of the voltage drops measured via electron energy analyzer shows that the conduction is provided by the surface of the diamond needles and is governed by Poole-Frenkel transport mechanism with characteristic trap energy of 0.2–0.3 eV. The temperature-sensitive FE characteristics of the diamond needles are of great interest for production of the point electron beam sources and sensors for vacuum electronics.

High frequency ultrasound to assess skin thickness in healthy adults

BackgroundIntradermal immunization is gaining increased attention due to multiple factors: (1) intradermal (ID) vaccination has been shown to induce improved immunogenicity compared to intramuscular (IM) vaccination; (2) ID vaccination has been shown to have a dose-sparing potential over IM leading to a reduced vaccine cost and an increased availability of vaccines worldwide. However, the currently used Mantoux technique for ID injection is difficult to standardize and requires training.The aim of the study was (1) to assess the epidermal and dermal thickness at the proximal ventral and dorsal forearm (PVF & PDF) and deltoid in adults aged 18–65years (2) to determine the maximum penetration depth and needle characteristics for the development of a platform of medical devices suited for intradermal injection, VAX-ID™. Materials and methodsMean thickness of the PVF, PDF and deltoid were measured using high-frequency ultrasound of healthy adults aged 18–65years. Correlation with gender, age and BMI was assessed using Mann-Whitney U Test, Spearman correlation and Wilcoxon Signed Ranks Test, respectively. ResultsResults showed an overall mean skin thickness of 1.19mm (0.65–1.55mm) at the PVF, 1.44mm (0.78–1.84mm) at the PDF, and 2.12mm (1,16–3.19mm) at the deltoid. Thickness of PVF & PDF and deltoid were significantly different for men vs women (pmean<0.001, <0.001, <0.001, and pmin<0.001, 0.012, <0.001, respectively). A significant association was found for age at the deltoid region (p<0.001). Skin thickness for PVF, PDF & deltoid was significantly associated to BMI (p<0.001). ConclusionSignificant differences in skin thickness were seen for the PVF, PDF and deltoid region for gender, and BMI. Age only influenced the skin thickness at deltoid region. A needle length of 1.0mm is best option for intradermal injection at the dorsal forearm (NCT02363465).

Analysis of needle type for musculoskeletal lesion biopsy: results of a novel steerable needle

Background: Needle biopsy has proven to be a potentially adequate method for initial biopsy of many soft-tissue and bone lesions. To help optimize this procedure, this study sought to test the characteristics of several needles, including a steerable needle. Materials and Methods: Five needle types were tested, including a steerable needle. Animal muscle tissue was used for all testing. The following experiments were performed: (1) sample collection with different needle types, (2) histological analysis of needle track, (3) observation of steerable needle characteristics using CT-guidance. Results: Sample collection: The Menghini 21 g and Chiba 22 g needles were graded as excellent for ease of use and integrity of sample. Histologic evaluation showed good specimen preservation with all needle types. Histological analysis of needle track: tracks created by the Menghini 21 g and Spinal 20 g needles both showed no histologically detectable damage to surrounding tissue. Observation of steerable Menghini needle under CT-guidance: needle advanced easily through tissue, even when maximally curved. Small, large, and double curves were feasible to avoid obstacles and reach targets. There was no deflection or change in position of the needle tip when the stylet was removed. Needle withdrawal did not damage surrounding tissue. Conclusions: Compared to the other needles, the steerable needle was found to be durable and easy to use, allowing for precise navigation around vital structures yielding superior integrity of sample tissue.

Varijabilnost širine četina duglazije (Pseudotsuga menziessii /Mirb./Franco) u provenijeničnim testovima

Introduced tree species which have a wide natural range of distribution should be tested in experiments with different provenances. Douglas-fir is a very productive conifer species in its natural forest stands of America and Canada. Because of its high value, it is very popular in the countries of Europe and New Zealand as a conifer species suitable for reforestation. Its genetics and ecological adaptability can be confirmed by the investigations of its variable morphological traits, which is the aim of this research. Needle characteristics and needle morphology play a very important role in the performance of plant functions. Needle structure has a great influence on the plant life-cycle and their resistance to water loss, temperature and CO2 levels. The characteristics and morphology of needles were studied in order to determine whether there are differences between the provenances. Two experimental plots with twenty Douglas-fir provenances originally from North America were established in Serbia. A two-way analysis of variance was aimed at a closer study of the effects of the interaction of the site conditions of Douglas-fir provenances in the test locations in Serbia on the morphological traits of the needles.