Probe Fixation Research Articles

TBAPy-based metal-organic frameworks with phosphate-induced fluorescence for detecting gossypol

How to achieve good dispersion of MOFs (metal–organic frameworks) is the key to its application in many fields. In our work, a novel MOF nanocomposite TBAPy-Yb was synthesized by solvothermal approach with TBAPy [1,3,6,8-tetrakis(p-benzoic acid)pyrene)] as the organic ligand and lanthanide metal ions as the metal ion source. Due to the coordination between phosphate and TBAPy-Yb, TBAPy-Yb had excellent dispersion in phosphate buffer and induced strong fluorescence emission in 435 nm. Gsp (gossypol) could regularly and instantly quench the induced fluorescence of TBAPy-Yb in the range of 10.0 to 70.0 μM and cause an obvious color change from blue to colorless. The detection limit was as low as 4.57 μM. The possible interferences in cottonseed oil did not influence the detection. The proposed method was effectively applied toanalyzeGsp oil with a recovery rate ranging from 94.20 % to 104.90 %. Furthermore, a portable and smart sensing platform was developed based on probe fixation and mobile phones.

Application of CRISPR/Cas12a in miRNA-155 detection: A novel homogeneous electrochemiluminescence biosensor

BackgroundMicroRNAs (miRNAs) are important non-coding RNA entities that affect gene expression and function by binding to target mRNAs, leading to degradation of the mRNAs or inhibiting their translation. MiRNAs are widely involved in a variety of biological processes, such as cell differentiation, development, metabolism, and apoptosis. In addition, miRNAs are associated with many diseases, including cancer. However, conventional detection techniques often suffer from shortcomings such as low sensitivity, so we need to develop a rapid and efficient detection strategy for accurate detection of miRNAs. ResultsWe have developed an innovative homogeneous electrochemiluminescence (ECL) biosensor. This biosensor employs CRISPR/Cas12a gene editing technology for accurate and efficient detection of microRNA (miRNA). Compared to conventional technologies, this biosensor employs a unique homogeneous detection format that eliminates laborious probe fixation steps and greatly simplifies the detection process. By using two amplification techniques - isothermal amplification and T7 RNA polymerase amplification - the biosensor improves the sensitivity and specificity of the assay, providing excellent detection performance in the assay. This makes it possible to evaluate miRNA directly from a variety of biological samples such as cell lysates and diluted human serum. Experimental results convincingly demonstrate the extraordinary performance of this biosensor, including its extremely low detection limit of 1.27 aM, high sensitivity, reproducibility and stability. SignificanceThe application of our constructed sensor in distinguishing between cancerous and non-cancerous cell lines highlights its potential for early cancer detection and monitoring. This innovative approach represents a major advancement in the field of miRNA detection, providing a user-friendly, cost-effective, and sensitive solution with broad implications for clinical diagnosis and patient care, especially in point-of-care settings.

Rapid, portable and visualizing nitrite detection enabled by a rationally designed meso-aminoindole substituted pyronine-based fluorescent probe

Nitrite (NO2−) widely exists in our daily diet, and its excessive consumption can lead to detrimental effects on the human central nervous system and an elevated risk of cancer. The fluorescence probe method for the determination of nitrite has developed rapidly due to its simplicity, rapidity and sensitivity. Despite establishing various nitrite sensing platforms to ensure the safety of foods and drinking water, the simultaneous achievement of rapid, specific, affordable, visualizing, and on-site nitrite detection remains challenging. Here, we designed a novel fluorescent probe by using Rhodamine 800 as the fluorescent skeleton and 5-aminoindole as the specific reaction group to solve this problem. The probe shows a maximal fluorescence emission at 602 nm, thereby avoiding background emission interference when applied to food samples. Moreover, this unique probe exhibited excellent sensing capabilities for detecting nitrite. These included: a rapid response time within 3 min, a noticeable color change that the naked eye can observe, a low detection limit of 13.8 nM, and a remarkable selectivity and specificity to nitrite. Besides that, the probe can detect nitrite quantitatively in barreled drinking water, ham sausage, and pickles samples, with good recoveries ranging from 89.0 % to 105.8 %. More importantly, based on the probe fixation and signal processing technology, a portable and smart sensing platform was fabricated and made convenient and rapid analysis the content of NO2− in real samples possible. The results obtained in this work provide a new strategy for the design of high-performance nitrite probes and feasible technology for portable, rapid and visual detection of nitrite, and this probe holds the potential as a practical tool for alleviating concern regarding nitrite levels.

Ultrasonographic reliability and repeatability of simultaneous bilateral assessment of diaphragm muscle thickness during normal breathing.

The diaphragm is considered the main muscle involved in breathing and also linked to trunk stabilization functions. Up to date, rehabilitative ultrasound imaging (RUSI) has been the most used technique to evaluate unilaterally the transcostal diaphragm thickness. Nevertheless, the inspiratory activity of both hemi-diaphragms is bilaterally performed at the same time, and its simultaneous evaluation with a thoracic orthosis could improve its assessment as well as its re-education with visual biofeedback of both hemi-diaphragms at the same time. The purpose was to evaluate the reliability and repeatability of simultaneous thickness measurements of both hemi-diaphragms bilaterally during normal breathing using a thoracic orthosis that allowed bilateral fixation of both right and left ultrasound probes. The study was conducted in 46 healthy subjects, whose diaphragm thickness was measured bilaterally and simultaneously in the anterior axillary line during relaxed breathing with a designed thoracic orthosis and 2 ultrasound tools. Intra-examiner (same examiner), inter-examiner (2 examiners), intra-session (1 hour) and inter-session (1 week) reliability and repeatability between each pair of measurements of diaphragm muscle thickness were analyzed during normal breathing. Reliability and repeatability for intra-session evaluations using the thoracic orthosis were excellent to evaluate simultaneous thickness of both hemi-diaphragms by bilateral probes fixation (intraclass correlation coefficient =0.919-0.997; standard error of measurement =0.002-0.007 cm; minimum detectable change =0.006-0.020 cm), without systematic errors (P>0.05) between each pair of measurements. Nevertheless, inter-session evaluations varied from good to excellent using the bilateral probes fixation (intraclass correlation coefficient =0.614-0.984; standard error of measurement =0.006-0.028 cm; minimum detectable change =0.017-0.079 cm), although some systematic errors were presented (P<0.05). Good to excellent reliability and repeatability was shown for simultaneous thickness measurements of both hemi-diaphragms bilaterally during normal breathing. Despite systematic errors were presented for some inter-examiner assessments, the use of the thoracic orthosis that allowed bilateral fixation of ultrasound probes could be recommended for simultaneous hemi-diaphragms breathing re-education by visual biofeedback.

Vibro-acoustic characterization of the bone-implant system during insertion

The femoral stem primary stability achieved by the impaction of a beam called “ancillary” attached to the implant during its insertion is an important factor of success in cementless surgery. However, surgeons rely on their proprioception, making the process subjective. The use of experimental modal analysis (EMA) without sensor nor probe fixation on the implant or on the bone is a promising non-destructive approach to determine implant stability. This study investigates whether EMA performed directly on a beam, which is temporary fixed to the implant during its insertion, could provide information on the boundary condition, which corresponds to the implant stability. A cementless femoral stem was inserted into 10 bone phantoms of human femurs and EMA was carried out on the ancillary using a dedicated impact hammer for each insertion step. Two bending modes were identified in the frequency range 400–8000 Hz for which the resonance frequency was shown to be sensitive to the insertion step and to the bone-implant interface properties. A significant correlation was obtained between the two modal frequencies and the implant insertion depth (R² = 0.95 ±0.04 and R² = 0.94 ±0.06). This study opens new paths towards the development of noninvasive vibration-based evaluation methods to monitor cementless implant insertion.

Pilot Study of the Impact of a Head-Mounted Display and Probe Fixation for Ultrasound-Guided Peripheral Intravenous Cannulation

Highlights Abstract Background: Ultrasound is an efficient and effective technique to aid intravenous cannulation, in which good hand-eye coordination is crucial. To reduce the difficulty, the ultrasound image should be projected and visible in front of the practitioner during cannulation, and the probe should be stabilized on the target vein. The current study investigates the impact of a head-mounted display and probe fixation for ultrasound-guided peripheral intravenous cannulation success and time needed to successful insertion. Materials and Methods: This nonclinical pilot study included 49 nurse anesthetists. They were divided into an intervention group (cannulation with a head-mounted display and probe stabilizer for ultrasound-guided peripheral intravenous cannulation, n = 24) and control group (conventional method of ultrasound-guided cannulation, n = 25). Participants performed 20 procedures each on phantoms, with focus on first attempt cannulation success and time taken to completion of successful cannulation. Results: In the intervention group, 98% succeeded on their very first attempt at cannulation, compared to 52% in the control group (P &amp;lt; 0.001). Time to successful cannulation on the first attempt was 1.13 ± 0.4 minutes in the intervention group, compared with 1.69 ± 0.8 minutes in the control group (P = 0.003). Overall, first attempt cannulation success was 92% in the intervention group and 90% for the control group (P = 0.359). Times required for successful cannulation was reduced by 0.08 minutes in the intervention group (P &amp;lt; 0.001). Conclusions: This pilot study is the first describing the use of a head-mounted display and probe fixation for ultrasound-guided peripheral intravenous cannulation, which resulted in an increased success rate and decreased time to cannulation success.

Medical device-related pressure injury prevention related to fixation of nutritional and derivative probes: a best practice implementation project.

The main objective was to improve the provision of clinical care in pressure injury prevention related to the use of medical devices focused on nasogastric probes. The insertion of nasogastric probes could lead to the formation of medical device-related pressure injuries (MDRPI). The risk increases with the length of the probe insertion and is higher in patients in intensive care. MDRPI prevention is mostly based on appropriate skin and mucosa membrane and tissue monitoring and positioning of the medical devices. The project has been conducted based on JBI Implementation approach for promoting change in healthcare practice. A baseline audit on MDRPI prevention was undertaken and involved 21 nurses and 12 patients using a questionnaire for nurses and a record sheet for patient's monitoring. The intervention included education, clinical practice training, consultation, and other strategies. A follow-up audit was undertaken, including all original participants. Results data on changes in compliance were measured using descriptive statistics embedded in JBI-PACES in the form of percentage changes from baseline. There were significantly improved outcomes across all best practice criteria. The level of knowledge of nurses increased. Skin barrier creams and mass-supplied fixation are now used to prevent skin injuries on the nose. The new monitoring and documentation is more accurate and in line with evidence-based practice. Overall, the project achieved an improvement in evidence-based practice in the prevention of MDRPI in patients with nasogastric probes based on nurses' increased level of knowledge and usage of appropriate preventative measures.

Development of a Novel Electrochemical Sensor Based on Functionalized Carbon Black for the Detection of Guanine Released from DNA Hydrolysis

AbstractIn this work, we reported a new strategy based on DNA strands hydrolysis in combination with the employment of functionalized carbon black modified screen‐printed electrode (f‐CB/SPE) for guanine detection. Using glass microbeads as a solid substrate of ssDNA probe fixation, and under appropriate conditions of temperature, time, and hydrochloric acid concentration, DNA hydrolysis has been successfully used to release the guanine, allowing its oxidation at f‐CB/SPE using differential pulse voltammetry. The selectivity was successfully tested with a non‐complementary sequence, and a detection limit of 0.7 nM of the target DNA has been reached.

Continuous hands-free monitoring of echocardiographic exercise test using probe fixation device.

Stress echocardiography has been widely used in clinical practice for decades and has recently gained even more importance in diagnostic approaches to ischemic heart disease. However, it still has numerous limitations. Despite advantages of physical exercise as most physiologic stressor, it is impossible to continuously monitor the cardiac function during treadmill test and difficult to maintain an optimal acoustic window during cycle ergometer exercise tests. The aim herein, is to assess the feasibility of probe fixation for use during exercise echocardiography. Forty-eight subjects (47 men, mean age 42 ± 17 years, 25 healthy volunteers, 23 patients with suspected coronary artery disease) were included in this study. All subjects underwent exercise stress test on treadmill (32 cases) or cycle ergometer (16 cases). Both sector and matrix probes were used (in 17 and 31 tests, respectively). The semi-quantitative quality of acquired apical views were assessed at each stage using a four-point grading system. The mean time required for probe fixation was 9 ± 2 min. At baseline, 10 patients had at least one apical window of quality precluding reliable analysis. Twenty-five patients required probe repositioning during exercise (more often on a treadmill). During peak exercise quality of images in all views declined, but for diagnostic purposes it remained sufficient in 29 patients. Thus, 76% of performed tests (60% study population) had sufficient image quality. Probe fixation offers the possibility of continuous acquisition of echocardiographic images during physical exercise. The device is suitable almost exclusively for male patients and in some patients requires repositioning.

Modal Analysis of the Ancillary During Femoral Stem Insertion: A Study on Bone Mimicking Phantoms.

The femoral stem primary stability achieved by the impaction of an ancillary during its insertion is an important factor of success in cementless surgery. However, surgeons still rely on their proprioception, making the process highly subjective. The use of Experimental Modal Analysis (EMA) without sensor nor probe fixation on the implant or on the bone is a promising non destructive approach to determine the femoral stem stability. The aim of this study is to investigate whether EMA performed directly on the ancillary could be used to monitor the femoral stem insertion into the bone. To do so, a cementless femoral stem was inserted into 10 bone phantoms of human femurs and EMA was carried out on the ancillary using a dedicated impact hammer for each insertion step. Two bending modes could be identified in the frequency range [400-8000] Hz for which the resonance frequency was shown to be sensitive to the insertion step and to the bone-implant interface properties. A significant correlation was obtained between the two modal frequencies and the implant insertion depth (R2=0.95±0.04 and R2=0.94±0.06). This study opens new paths towards the development of noninvasive vibration based evaluation methods to monitor cementless implant insertion.

Electrical Impedance Plethysmography Versus Tonometry To Measure the Pulse Wave Velocity in Peripheral Arteries in Young Healthy Volunteers: a Pilot Study.

The leading cause of health loss and deaths worldwide are cardiovascular diseases. A predictor of cardiovascular diseases and events is the arterial stiffness. The pulse wave velocity (PWV) can be used to estimate arterial stiffness non-invasively. The tonometer is considered as the gold standard for measuring PWV. This approach requires manual probe fixation above the artery and depends on the skills of the operator. Electrical impedance plethysmography (IPG) is an interesting alternative using skin surface sensing electrodes, that is miniaturizable, cost-effective and allows measurement of deeper arteries. The aim of this pilot study was to explore if IPG can be a suitable technique to measure pulse wave velocity in legs as an alternative for the tonometer technique. The PWV was estimated by differences in the ECG-gated pulse arrival times (PAT) at the a. femoralis, a. popliteal, a. tibialis dorsalis and a. dorsalis pedis in nine healthy young adults using IPG and the SphygmoCor tonometer as a reference. The estimated PWV results from bioimpedance and the tonometer were fairly in agreement, and the beat-to-beat variability in PAT was similar. This pilot study indicates that the use of IPG may be a good alternative for estimating PWV in the legs.

Exercise stress echocardiography with probe fixated on patient's chest

Abstract Background Stress echocardiography (SE) has been widely used in clinical practice for decades and recently has gained even more importance in diagnostic approach to ischemic heart disease. However, it still has numerous limitations. Despite advantages of physical exercise as most physiologic stressor, it is impossible to continuously monitor the cardiac function during treadmill test and difficult to maintain an optimal acoustic window during cycle ergometer exercise test. We aimed to assess the feasibility of probe fixation for the use during exercise echocardiography. Methods 48 subjects (47 men, mean age 42±17 years, 25 healthy volunteers, 23 patients with suspected coronary artery disease) were included in this study. All subjects underwent exercise stress test on treadmill (32 cases) or cycle ergometer (16 cases). Both sector and matrix probes were used (in 17 and 31 tests, respectively). We assessed semi-quantitatively the quality of acquired apical views at each stage using four-point grading system (0 = poor, 1 = suboptimal, 2 = acceptable, 3 = optimal). Results The mean time required for probe fixation was 9±2 min. At baseline, 10 patients had at least one apical window of quality precluding reliable analysis. 25 patients probe repositioning during exercise (more often on treadmill). During peak exercise quality of images in all views declined, but it remained sufficient in 29 patients for diagnostic purposes. Thus, 76% of performed tests (60% for all study population) were of sufficient image quality. Conclusion Probe fixation offers the possibility of continuous acquisition of echocardiographic images during physical exercise. However the device is suitable almost exclusively for male patients. Moreover, in some patients it requires repositioning. Funding Acknowledgement Type of funding sources: None.

A novel sandwich-type electrochemical biosensor enabling sensitive detection of circulating tumor DNA

It is of great importance to accurately analyze circulating tumor DNA (ctDNA), for the reason that it serves as one of the particularly informative cancer biomarkers for disease diagnosis, therapy, and prognosis. However, sensitive detection of ctDNA remains a challenging task and the design of feasible sensing method plays a significant role in ctDNA analysis. In this work, a novel sandwich-type electrochemical biosensor was developed through a facile way for sensitive detection of ctDNA using nanocomposites (MWCNTs-PDA-Au-Pt) as signal probes’ (SPs) label (SPs-label) for signal amplification. The current response of the nanocomposites towards H2O2 reduction was used to quantitatively detect target DNA and distinguish base-mismatched DNA sequences. Characterizations reveal that Au-Pt alloy nanoparticles are uniformly dispersed on MWCNTs-PDA and the resultant MWCNTs-PDA-Au-Pt shows excellent response toward the reduction of H2O2, which could largely amplify the current response. Electrochemical analysis of electrode modification process confirms that the sandwich-type structure was successfully formed through step-wise reactions, including fixation of capture probes (CPs) on the surface of the screen-printed gold electrode, recognition between CPs and target DNA (T-DNA), hybridization between T-DNA and SPs. Under optimal experimental conditions, the proposed ctDNA biosensor exhibits a wide linear range from 1 × 10−15 to 1 × 10−8 mol/L with a detection limit as low as 5 × 10−16 mol/L (S/N = 3), unprecedented selectivity towards T-DNA and other base-mismatched DNAs (even for only single base-mismatched sequences), and superb long-term stability. This work demonstrates the sandwich-type scheme is a promising method for practical applications in clinical ctDNA diagnosis.

Sensitive electrochemical detection of oxytetracycline based on target triggered CHA and poly adenine assisted probe immobilization

Here, we developed a homogeneous electrochemical biosensor for the sensitive determination of antibiotic by the CHA reaction and the consecutive adenine mediated probe fixation. The binding of target to the target recognition sequences in the triple-helix DNA can release the trigger. It can initiate the catalytic hairpin assembly (CHA) to generate lots of mimic targets, which were labeled with electroactive substance ferrocene (Fc). Because the generated mimic target has consecutive sequence of adenines (PolyA), they can be self-assembled on the AuNPs modified electrode and finally realize electrochemical detection. Under optimal conditions, this developed biosensor achieved a satisfactory limit of detection of 0.089 nM (S/N = 3) and a linear range from 0.1 nM to 100 nM for sensitive detection of oxytetracycline with good specificity. The whole process is carried out in homogeneous solution, not only realizes signal amplification, but also avoids the complex modification process of electrode surface. Compared with some reported electrochemical sensors, the method is easier to operate and has good precision.

Handheld laser-fiber vibrometry probe for assessing auditory ossicles displacement.

.Significance: Measurements of auditory ossicles displacement are commonly carried out by means of laser-Doppler vibrometry (LDV), which is considered to be a gold standard. The limitation of the LDV method, especially for in vivo measurements, is the necessity to expose an object in a straight line to a laser beam operating from a distance. An alternative to this approach is the use of a handheld laser-fiber vibrometry probe (HLFVP) with a curved tip.Aim: We evaluate the feasibility of an HLFVP with a curved tip for measuring sound-induced displacement of the auditory ossicles.Approach: A handheld vibrometer probe guiding the laser beam with a fiber-optic cable was used for displacement measurements of the incus body and the posterior crus of the stapes. Tonal stimuli at frequencies of 0.5, 1, 2, and 4 kHz were presented by means of an insert earphone positioned in the outer ear canal. The probe was fixed at the measurement site using a tripod or hand-held by one of the two surgeons.Results: The measurements were carried out on six fresh temporal bones. Multivariate analysis of variance showed statistically significant differences for stimulus frequency (, , and ), bone (, , and ), and measurement site (, , and ) in the absence of statistically significant differences for the probe fixation method (, , and ). Standard deviations of the means were 6.9, 2.6, 1.9, and for frequency, bone, site, and fixation, respectively. Ear transfer functions were found to be consistent with literature data.Conclusions: The feasibility of applying HLFVP to measure the displacement of auditory ossicles has been confirmed. HLFVP offers the possibility of carrying out measurements at various angles; however, this needs to be standardized taking into account anatomical limitations and surgical convenience.

Concurrent Validity and Reliability of Manual Versus Specific Device Transcostal Measurements for Breathing Diaphragm Thickness by Ultrasonography in Lumbopelvic Pain Athletes.

The use of rehabilitative ultrasound imaging (RUSI) to evaluate diaphragm thickness during breathing in athletes who suffer from non-specific lumbopelvic pain presents some measurement errors. The purpose of this study was to evaluate intra- and inter-sessions, intra- and inter-rater reliabilities, and concurrent validity of diaphragm thickness measurements during breathing using transcostal RUSI with a novel thoracic orthotic device that was used to fix the US probe versus those measurements obtained using manual fixation. A total of 37 athletes with non-specific lumbopelvic pain were recruited. Intra- (same examiner) and inter-rater (two examiners) and intra- (same day) and inter-session (alternate days) reliabilities were analyzed. All measurements were obtained after manual probe fixation and after positioning the thoracic orthotic device to fix the US probe in order to correctly correlate both measurement methods. Both left and right hemi-diaphragm thickness measurements were performed by transcostal RUSI at maximum inspiration, expiration, and the difference between the two parameters during relaxed breathing. Intra-class correlation coefficients (ICC), standard errors of measurement (SEM), minimum detectable changes (MCD), systematic errors, and correlations (r) were assessed. Orthotic device probe fixation showed excellent reliability (ICC = 0.852–0.996, SEM = 0.0002–0.054, and MDC = 0.002–0.072), and most measurements did not show significant systematic errors (p > 0.05). Despite manual probe fixation with a reliability ranging from good to excellent (ICC = 0.714–0.997, SEM = 0.003–0.023, and MDC = 0.008–0.064 cm), several significant systematic measurement errors (p < 0.05) were found. Most significant correlations between both orthotic device and manual probe fixation methods were moderate (r = 0.486–0.718; p < 0.05). Bland–Altman plots indicated adequate agreement between both measurement methods according to the agreement limits. The proposed novel thoracic orthotic device may allow ultrasound probe fixation to provide valid and reliable transcostal RUSI measurements of diaphragmatic thickness during relaxed breathing thus reducing some measurement errors and avoiding systematic measurement errors. It may be advisable to measure diaphragm thickness and facilitate visual biofeedback with respect to diaphragm re-education during normal breathing in athletes with non-specific lumbopelvic pain.

Газохроматографический анализ жирных кислот фосфолипидов растений кукурузы в условиях разной аэрации

Липиды являются важнейшим структурным, запасным и функциональным компонентом рас-тительных клеток. При этом фосфолипиды, относящиеся к полярным липидам, являются интеграль-ными компонентами клеточных мембран, определяя вместе с белками их структуру и функции. В тоже время работ, посвященных изучению влияния дефицита кислорода на содержание липидов и их жир-нокислотный состав, в связи со сложностью методов изучения этих компонентов растительных клеток, крайне мало. Исследовали методом газожидкостной хроматографии состав и динамику изменения со-держания жирных кислот в фосфолипидах проростков кукурузы, подвергшихся воздействию кратко-временной (3-24час.) гипоксии. Липиды экстрагировали после фиксации проб кипящим изопропано-лом смесью гексан : изопропанол (3:2). Фосфолипиды из липидной фракции выделяли методом тонко-слойной хроматографии. Гидролиз фосфолипидов и метилирование жирных кислот проводили в запа-янных ампулах при +100оС в течение 2 часов. Газохроматографический анализ показал, что в фосфо-липидах проростков кукурузы доминирующими среди жирных кислот были пальмитиновая (С16:0) и линолевая C18:2) кислоты, содержание которых составляло 27.39 и 54.78% от суммы всех кислот. При дефиците кислорода в первые 3-6 часов содержание диеновой С18:2 кислоты в фосфолипидах снижа-лось, при этом индекс ненасыщенности (ИН) жирных кислот уменьшался с 1.15 (аэрация) до 0.96. Уменьшение в фосфолипидах проростков кукурузы при гипоксии содержания ненасыщенных жирных кислот могло быть обусловлено деструкцией фосфолипидов или усилением процессов перекисного окисления их жирных кислот под действием липоксигеназ. К 24 часам гипоксии содержание С18:2 воз-растало до уровня аэрируемых растений, вероятно за счет усиления синтеза. ИН жирных кислот фос-фолипидов повышался, но оставался еще ниже аэрируемых растений , так как снижалось содержание пальмитолеиновой (С16:1) кислоты с 7.74 до 0.92% и возрастало пальмитиновой (С16:0) кислоты до 29.17%. Проведенные исследования показали, что изменения в составе жирных кислот фосфолипидов растений, попадающих в условия дефицита кислорода (гипоксия) начинают проявляться уже при до-статочно коротких, часовых экспозициях (3-6 час), а не многосуточных, как ранее отмечалось. Пред-полагается, что восстановление уровня ненасыщенности жирных кислот фосфолипидов позволяет про-росткам кукурузы, относящимся к среднеустойчивым растениям, в условиях кратковременного дефи-цита кислорода стабилизировать структуру и свойства биологических мембран, что повышает их адап-тационные возможности.

Application effect of an ultrasound probe fixation bracket assisted ultrasound-guided venipuncture in difficult intravenous access

Objective To observe the effect of ultrasound probe fixation bracket assisted ultrasound-guided venipuncture in difficult intravenous access. Methods A total of 105 inpatients with difficult intravenous access from November 2017 to May 2019 were selected by convenient sampling method. From November 2017 to May 2018, 39 patients as the control group were treated with ultrasound-guided peripheral venous indwelling needle puncture technique. From June 2018 to May 2019, 66 patients as the experimental group were treated with ultrasound probe fixation bracket assisted ultrasound-guided peripheral vein indwelling needle puncture technique. The success rate of one needle puncture, the times of puncture and the degree of pain were compared between the two groups. Results The success rate of one needle puncture was 92.4% (61/66) in the experimental group and 66.7% (26/39) in the control group (χ2 value was 11.450, P<0.01); The puncture times in the experimental group and the control group were 1.08±0.27 and 1.44 ±0.72, and the difference was statistically significant (Z value was -3.435, P<0.01). The pain scores of the experimental group and the control group were 2.00 ± 0.95 and 3.08±1.37, and the difference was statistically significant (Z value was -4.159, P<0.01). Conclusions The application of ultrasound probe fixation bracket assisted ultrasound-guided peripheral venipuncture technique in patients with difficult intravenous access can improve the success rate of one needle puncture, reduce the number of puncture and reduce the degree of pain. Key words: Ultrasound-guided; Peripheral vein; Indwelling needle; Vascular grading; Difficult intravenous access

P1398 Echocardiographic continuous monitoring of exercise stress test using probe fixation device

Abstract Background Stress echocardiography (SE) plays an important role among methods of noninvasive diagnosis of ischemic disease. Despite the advantages of physical exercise as the most physiologic stressor, it is difficult (bicycle ergometer) or impossible (treadmill) to obtain and maintain the acoustic window during the exercise. Recently, an innovative probe fixation device was introduced and a research plan was developed to assess the feasibility of external probe fixation during exercise echocardiography on a supine bicycle and upright treadmill exercise for the first time. Methods 37 subjects (36 men, mean age 39 ± 16 years, 21 healthy volunteers, 16 patients with suspected coronary artery disease) were included in this study. This preliminary testing stage included mostly men due to more problematic probe fixation in women. All subjects underwent a submaximal exercise stress test on a treadmill (17/37) or bicycle ergometer (11/37). Both sector and matrix probes were used. We assessed semi-quantitatively the quality of acquired apical views at each stage – the four-point grading system was used (0-no view, 1-suboptimal quality, 2-optimal quality, 3-very good quality), 2-3 sufficient for diagnosis. Results The mean time required for careful positioning of the probe and image optimization was 12 ± 3 min and shortened from 13,7 to 11,1 minutes (mean) in first vs second half of the cohort documenting learning curve. At baseline, 9 patients had at least one apical view of quality precluding reliable analysis. Those patients were excluded from further assessment. During stress, 17 patients maintained the optimal or very good quality of all apical views, whereas in 11 patients the quality significantly decreased during the stress test and required probe repositioning. The mean image quality score at baseline was 2,61 ± 0,48 and 2,25 ± 0,6 after exercise. Expectedly, good image quality was easier to obtain and maintain in the supine position (score 2,74 ± 0,44) points as compared with upright position (score 2,25 ± 0,57). Conclusion This preliminary, unique experience with external probe fixation device indicates that continuous acquisition and monitoring of echocardiographic images is feasible during physical exercise, and for the first time ever - also on the treadmill. This feasibility data stem from almost exclusively male patients and the estimated rate of sufficient image quality throughout the entire test is currently around 60%. We are hoping, that gaining more experience with the product could increase the success rate on exercise tests. Abstract P1398 Figure. Treadmill and ergometer stress test

P274 Continous echocardiographic monitoring in intensive cardiac care unit with external probe stabilizer - preliminary experience

Abstract Background The role of transthoracic echocardiography (TTE) in the intensive cardiac care unit is crucial. Imaging is currently performed at the bedside for diagnosis but TTE has also potential to noninvasively provide critical views to assist in patient monitoring. Continuous monitoring would be especially helpful when the patient is unstable; however, continuous availability of skilled sonographers to obtain appropriate views represents a limiting factor. Purpose Recently, an innovative external fixation device allowing prolonged stabilization of transthoracic ultrasound transducer was introduced. The ring-shaped device fitted for TTE probes is attached to the patient by elastic straps to hold the probe in contact with the skin at a fixed but adjustable angle. We developed a research project to assess for the first time the feasibility of continuous TTE imaging with external probe fixation in the intensive cardiac care unit. Methods 12 patients (10 men, mean age 66,5 ± 15 years) hospitalized in intensive cardiac care unit due to cardiac arrest, myocardial infarction, pulmonary embolism, end-stage heart failure or respiratory failure were included in the study. The echocardiographic probe be was fixed in the apical window providing a four-chamber view to monitor left ventricular function. We assessed the patient’s tolerance and comfort as well as the quality of images acquired at baseline and at the end of monitoring. Results Fixation of the probe was successful in all patients (figure 1). The mean time of fixation was 10 ± 1 minute, with a clear learning curve. The quality of obtained images was sufficient for evaluation and was maintained throughout the entire period of monitoring in all patients. Monitoring was stopped at patients’ request when discomfort caused by the compression of the skin by the probe and the fixation device became significant (figure 2). The mean duration of monitoring was 85 + 64 minutes (range 15 to 240 minutes). Conclusions In this preliminary series we have demonstrated for the first time the feasibility of echocardiographic continuous monitoring of patients in the intensive cardiac care unit using TTE probe with the external fixation device. The design of the fixation device opens the evident field for optimization to extend monitoring duration at acceptable levels of discomfort in conscious intensive care patients. We hope the improved version of the fixator will decrease the pressure on the body. Abstract P274 Figure. Fixation of the device