High Pressure Syringe Research Articles

Mycobacterium abscessus pulmonary infection and associated respiratory function in cystic fibrosis-like βENaC mice

IntroductionChronic pulmonary infection with Mycobacterium abscessus (M. abscessus) is a significant cause of morbidity and mortality in people with cystic fibrosis (CF). Developing an animal model of M. abscessus pulmonary infection, especially under CF conditions, is essential to understanding clinical pulmonary M. abscessus infection. βENaC transgenic mice are known to develop spontaneous CF-like disease characterized by airway mucus obstruction and inflammation. The aim of this study was to evaluate the suitability of βENaC mice as a preclinical model and characterize their respiratory function during M. abscessus lung infection.MethodsMice received an intrapulmonary aerosol of M. abscessus using a high-pressure syringe device (Penn-Century) for subsequent characterization of disease progression and respiratory function. Whole body unrestrained plethysmography (WBP) data was collected to monitor lung function and endpoints determined organ bacterial burden and associated pathology.ResultsEndpoint CFU data in the lung and spleen showed that there was no significant difference in bacterial clearance between βENaC and WT mice. WBP data showed an impairment in overall respiratory function during and after M. abscessus infection in both strains of mice. Interestingly, even in wildtype control mice, lung dysfunction persisted after bacterial clearance.DiscussionEven with CF-like features, the βENaC transgenic mice cleared M. abscessus at a similar rate than WT mice, however, the associated respiratory monitoring revealed that there are long-term implications of M. abscessus lung exposure. The clear decline in respiratory function, even after M. abscessus clearance, suggests that WBP coupled animal modeling provides important insight that is relevant to disease burden and treatment efficacy. The M. abscessus clearance in the βENaC mice may help improve the fields understanding of CF-modulated immune deficiencies in M. abscessus pulmonary infection.

Research on precise and stable seed flow delivery control for plasma MHD power generation

In this paper, a technique for precise and stable delivery control of alkali metal seed flow is proposed and experimentally verified. A high-pressure syringe driven by a stepping motor delivers liquid alkali metal seeds through a pneumatic atomizing spray gun. The seed jet is uniformly mixed, heated, vaporized and ionized by the high-temperature main flow in the plasma generator to produce a plasma with high conductivity. Based on the high-temperature arc wind tunnel test platform, an experimental study of the alkali metal cesium seed flow measure and plasma ionization characteristics was carried out. The results show that the fluctuation range of the measured seed flow was 5.93-10.39% at a small flow rate of 19 mL/min. For the back pressure of 6 atm, the fluctuation range of the measured seed flow is 6.04-11.55%, which proves that the back pressure of the plasma generator has insignificant effect on the seed flow. The plasma ionization characteristics test shows that the conductivity of the argon cesium equilibrium plasma is between 26.93-31.69 S/m, indicating that the ionization characteristics of the plasma are relatively stable, which can indirectly prove that the seed system has a precise and stable flow rate during the actual power generation. Key words: MHD power generation, alkali metal seed, seed fraction, precise and stable injection. Tables 1, Figs 9, Refs 11.

Development of a novel technique with a pigtail catheter and high-pressure injector for coronary postmortem computed tomography angiography

ABSTRACT Coronary post-mortem computed tomography angiography (coronary PMCTA) is a non-invasive method to evaluate the coronary artery in the forensic practice. A traditional method is to insert a urinary catheter through the carotid artery. In this study, we performed the coronary PMCTA by inserting a pigtail catheter through the femoral artery and connecting the catheter to a high-pressure syringe. We report the efficacy of this technique and factors influencing its performance, including the position of the catheter tip, aortic gas, high-pressure injector, and location of skin puncture. A total of 14 cadavers were included in our study. Two cadavers with coronary artery occlusions were identified in the PMCTA, which were confirmed by the autopsy reports. In addition, we found that adequate imaging of all the branches of the left and right coronary arteries could be achieved when the catheter tip was located in the ascending aorta around the aortic valve. Gas in the aorta could affect the image acquisitions, which could be avoided by priming the catheter with normal saline and changing the cadaver positions. The femoral artery insertion of the pigtail catheter with a high-pressure injector could achieve satisfactory images without causing obvious disfiguration of the cadavers.

Use of Irrigation Device for Duct Dilatation during Sialendoscopy

Continuous irrigation of the duct with isotonic saline is one of the fundamental stages of a successful sialendoscopic procedure. It allows for an adequate luminal distension for the removal of debris and mucous plugs and for the conservative treatment of strictures. This procedure, which commonly involves the use of a medical syringe, can be laborious, and it is often necessary to interrupt irrigation during surgery due to the high resistance to saline. Academic university hospital. We propose the use of an irrigation device which consists of a high-pressure syringe barrel, an ergonomic piston handle, and a gauge used to monitor the inflation and deflation of balloon catheters. The system allows for a simple and safe dilation, ensuring good visualization of the salivary duct lumen during sialendoscopy. The irrigation system described can be widely used to perform a diagnostic or interventional sialendoscopy more effectively than with a typical manual irrigation procedure.

Salvage of Infected Penile Prosthesis using Novel High-Pressure Pulse Irrigation System Adapted to Urological Use in Conjunction with a new Antimicrobial Solution

ABSTRACT Introduction Infection of a penile implant is a catastrophic event necessitating removal of the infected device. Removal of an infected implant is associated with significant morbidity, including penile fibrosis with associated shortening. Delayed reimplantation is associated with difficulty or maybe technically impossible. Mulcahy salvage protocol with modifications is the preferred approach when possible. Adequate irrigation is a challenge given the ‘deep-in-a-hole’ surgical anatomy where the implants are placed. In addition, there is no agreed-upon irrigant that is ideal for irrigation infected wounds. Objective We describe adaptation and modification of orthopedic high-pressure irrigation system for use in the salvage of penile prosthesis. In addition, we describe novel use in urology of a hypochlorous washing solution capable of removing microorganisms, disrupting biofilm, while being non-cytotoxic and skin-neutral. Methods Stryker Interpulse Pulsed Lavage System generating 15 pounds per square inch (PSI) of pressure was adapted for urological use in deep cavities using 16F red rubber Bard urethral catheter. Infected implant in a high-risk multiple comorbidities vasculopath was successfully salvaged without complications. Results Successful salvage of an infected penile prosthesis with a novel adaptation of existing high-pressure irrigation system. Demonstrated safely of use of antibiotic solution for penile irrigation. Conclusions In-vivo studies show significantly greater effectiveness of high-pressure pulsed salvage irrigation compared to bulb syringe irrigation. We present a practical, accessible, and effective modification of an existing high-pressure irrigation syringe for use in deep cavities, proximal and distal penile shaft. In addition, we report safe use of a new antimicrobial irrigant, hypochloric acid, for salvage of infected penile prosthesis. Disclosure No

Nursing Experience of CT Angiography with High Pressure Syringe

Nursing Experience of CT Angiography with High Pressure Syringe

Hemodynamic study of unenhanced magnetic resonance angiography using spatial labeling with multiple inversion pulses sequence: a phantom study.

This study sought to explore the functional relationship between displayed vascular length and blood suppression inversion time (BSP TI) and flow velocity in a phantom, and to provide a theoretical basis for quantitatively assessing vascular hemodynamic responses using unenhanced magnetic resonance angiography (MRA) and spatial labeling with multiple inversion pulses sequence (SLEEK). A polyethylene catheter was laid in a long rectangular container filled with pork fat. The entrance of the catheter into the container was connected to a high-pressure syringe filled with normal saline. The high-pressure injector flow rates were set at 0.0, 0.2, 0.4, 0.8, 1.2, 1.6, 2.0, and 2.4 mL/s. SLEEK was performed 19 times for each flow rate with parameter BSP TI values of 50, 75, 100, 150, 200, 300, 400, 500, 600, 700, 800, 900, 1,000, 1,100, 1,200, 1,300, 1,400, 1,600, and 1,800 ms. Maximum intensity projection was employed to reconstruct all SLEEK original images to determine the measurements of the displayed vascular lengths. A regression analysis was undertaken to assess the relationship between the displayed vascular lengths and BSP TI values for each flow rate, and to assess the relationship between the displayed vascular lengths and flow rates at each BSP TI. The displayed vascular length had a linear relationship with BSP TI for each flow rate (P<0.05) (R2=0.754, 0.941, 0.988, 0.988, 0.977, 0.966, and 0.982 for flow rates of 0.0, 0.2, 0.4, 0.8, 1.2, 1.6, and 2.0 mL/s, respectively). The displayed vascular length also had a linear relationship with flow rate for each BSP TI value (P<0.05) (R2 =0.914, 0.912, 0.834, 0.989, 0.980, 0.996, 0.992, 0.960, 0.975, 0.979, 0.982, 0.981, 0.976, and 0.993 for BSP TI 50, 75, 100, 150, 200, 300, 400, 500, 600, 700, 800, 900, 1,000, and 1,100 ms, respectively). No significant linear relationship was found between displayed vascular length and flow rate when the BSP TI value was 1,200 ms (P>0.05). Vascular displayed length has a linear relationship to BSP TI for flow ranges from 0.0 to 2.0 mL/s. Vascular displayed length has a linear relationship to flow rate for BSP TI values of 50 to 1,100 ms. Flow rate can be assessed in relation to vascular displayed length.

Intraoperative Nursing Care of Patients Undergoing Transcatheter Aortic Valve Replacement via Femoral Artery Approach

<i>Objective:</i> Intend to explore the main points of intraoperative nursing care of patients with aortic valve stenosis undergoing transcatheter aortic valve replacement through femoral artery approach, summarize the scientific and effective nursing methods in operation. <i>Methods:</i> The intraoperative nursing methods of 9 patients undergoing transcatheter aortic valve replacement through femoral artery approach in our hospital from November 2019 to January 2021 were analyzed retrospectively. These methods include preoperative preparation, transmission of operative consumables, invasive blood pressure monitoring, use of high pressure syringe and temporary pacemaker, nursing of balloon dilatation and valve release, observation and nursing of intraoperative complications, postoperative nursing and so on. <i>Results:</i> The success rate of transcatheter aortic valve replacement was 100% in 9 patients who underwent transcatheter aortic valve replacement through femoral artery approach. In addition, the average operation time was 194.1 minutes. Besides, 1 case was implanted with middle valve, 1 case was protected by coronary artery, and 1 case was rescued during postoperative transportation. Moreover, no serious operative complications such as valve stent shedding, perivalvular leakage, coronary artery occlusion, stroke and malignant arrhythmia occurred in 9 patients. <i>Conclusion:</i> Full preoperative preparation, familiarity with the whole operation process and key steps, proficiency in the use of high pressure syringe and temporary pacemaker and nursing cooperation during balloon dilatation and valve release are the key to the successful completion of the operation in transfemoral approach transcatheter aortic valve replacement. Through active and effective intraoperative nursing, the operative quality of transfemoral artery approach transcatheter aortic valve replacement can be improved effectively, the operative time can be shortened, and the occurrence of intraoperative complications can be reduced, and the life safety of patients can be guaranteed.

Application of diffusion tensor imaging and blood oxygenation level-dependent magnetic resonance imaging to assess bilateral renal function induced by Iohexol in rabbits

BackgroundBlood oxygenation level-dependent magnetic resonance imaging (BOLD-MRI) and diffusion tensor imaging (DTI) are useful methods for investigating the morphology and function of the kidneys, including revealing unilateral renal damage. Nevertheless, these techniques have not yet been applied for bilateral renal function. The aim of this study was to investigate whether the combination of DTI and BOLD could be used to examine different degrees of contrast-induced acute kidney injury (CI-AKI) in bilateral kidneys compared to standard methods such as serum creatinine (SCr) detection.MethodsForty-Two New Zealand white rabbits were divided into two groups: the experimental group and the control group. Physiological saline and iodine contrast agent (iohexol, 1.0 g iodine/kg, 1.0 ml/sec) were injected via the right renal artery. DTI and BOLD-MR data were acquired longitudinally at the baseline and 1, 24, 48, and 72 h after high-pressure syringe injection to measure the apparent diffusion coefficient (ADC), fractional anisotropy (FA) and relative transverse relaxation rate (R2*). After the MR scan at each time point, three rabbits in each group were sacrificed, and changes in SCr and hypoxia-inducible factor-1α (HIF-1α) were analyzed using histopathology and immunochemistry.ResultsTwenty-four hours after iohexol administration, the values of ADC and FA decreased significantly (P < 0.05), while R2* values increased (P < 0.05) in the renal cortex (CO), outer medulla (OM) and inner medulla (IM). Besides, significant negative correlations were observed among ADC, FA, and R2* in CO, OM, and IM (all P < 0.001, r = − 0.654–0.828).ConclusionsDTI and BOLD can simultaneously and non-invasively assess different degrees of CI-AKI in bilateral kidneys.

Portable capillary liquid chromatography for pharmaceutical and illicit drug analysis.

A newly developed portable capillary liquid chromatograph was investigated for the separation of various pharmaceutical and illicit drug compounds. The system consists of two high-pressure syringe pumps capable of delivering capillary-scale flow rates at pressures up to 10000psi. Capillary liquid chromatography columns packed with sub-2μm particles are housed in cartridges that can be inserted into the system and easily connected through high-pressure fluidic contact points by simply applying a specific, predetermined torque rather than using standard fittings and less precise sealing protocols. Several over-the-counter analgesic drug separations are demonstrated, along with a simple online measurement of tablet dissolution. Twenty illicit drug compounds were also separated across six targeted drug panels. The results described in this study demonstrate the capability of this compact liquid chromatography instrument to address several important drug-related applications while simplifying system operation, and greatly reducing solvent usage and waste generation essential for onsite analysis.

Development of a parallel microbore hollow fiber enzyme reactor platform for online 18O-labeling: Application to lectin-specific lung cancer N-glycoproteome

We introduce a simple online 18O-labeling protocol for protein samples that uses a parallelizing microbore hollow fiber enzyme reactor (mHFER) as an alternative tool for online proteolytic digestion. Online 18O-labeling is performed by separately attaching two mHFERs in parallel to a 10-port switching valve with a high-pressure syringe pump and two syringes containing 16O- or 18O-water. 16O-/18O-labeled peptides are formed in this manner and simultaneously analyzed online using nanoflow liquid chromatography-tandem mass spectrometry (nLC-MS/MS) without any residual trypsin activity. The usefulness of a parallel mHFER platform (P-mHFER) in 18O-labeling was tested using both cytochrome C and alpha-1-acid-glycoprotein to verify the incorporation level of two 18O atoms into tryptic peptides and to provide a quantitative assessment with varied mixing ratios. Additionally, our 18O-labeling approach was used to study the serum N-glycoproteome from lung cancer patients and controls to evaluate the applicability of lectin-based quantitative N-glycoproteomics. We successfully quantified 76 peptides (from 62 N-glycoproteins). Nineteen of these peptides from lung cancer serum were up-/down-regulated at least 2.5-fold compared to controls. As a result, the P-mHFER-based online 18O-labeling platform presented here can be a simple and reproducible way to allow quantitative proteomic analysis of diverse proteome samples.

Preparation of oil-in-water nanoemulsions at large-scale using premix membrane emulsification and Shirasu Porous Glass (SPG) membranes

Nanoemulsions are increasingly used in cosmetics, pharmaceutics and food. They are produced usually by low or high energy techniques. In this study, a process involving moderate pressure in the range 10–60 bar was proposed as an alternative, in particular for the encapsulation of sensitive actives or applications that require a precise droplet size control. Oil-in-water (O/W) nanoemulsions were prepared by premix membrane emulsification (PME) using a set-up with a controlled high pressure syringe pump and 125 mm long SPG membrane. A coarse emulsion (premix) was injected through the membrane with pore size between 0.2 and 0.8 μm in order to reduce and homogenize the droplet size. The effect of several parameters was investigated: process parameters (scalability, cycle number, membrane pore size, flowrate) or formulation (oil and surfactant concentrations). Nanoemulsions were prepared at large scale up to 500 mL at production rate up to 200 mL/min, pressure below 60 bar and one cycle. The droplet size was linearly related to the membrane pore size and highly monodisperse nanoemulsions of around 260 nm in diameter and stable for 9 months at room temperature were achieved with the smallest pore size membrane (0.2 μm). Moreover, the mechanisms involved in PME for nanoemulsions were discussed, such as flow through the membrane pores and droplet disruption by wall shear stress inside the membrane porous structure.

An analysis of 200 cases of abdominal enhancement scan on the 64-row CT scan

Objective To discuss the main points of abdominal enhancement scanning on the 64-row spiral CT. Methods 200 patients with CT scan were selected.For patients with abdominal CT scan, the contrast agent was used in accordance with the 1.5mL/kg, handle and dorsal vein with high pressure syringe injection, the pressure of 300 pounds, flow rate of 2.5mL/s, note medicine before scanning, note after the drug was not phase scanning 2-3 times at the same time. Results 180 cases showed the abdominal aorta, hepatic artery, splenic artery, hepatic portal vein branch, portal vein, and inferior vena cava.In 20 cases, the results were not ideal, and 3 cases failed. Conclusion The upper abdomen enhancement scan of the 64-row CT scan can obtain satisfactory images to meet clinical needs. Key words: 64-row CT; CT enhancement scan; Abdominal examination; CT image

Exploring Mechanisms of Biofilm Removal.

ObjectiveThe goal of this study was to evaluate the effects of a novel anti-plaque formulation on oral biofilm removal. Specific aim was to elucidate the role of 2 potentially complementary mechanisms on dental biofilm removal using EPIEN Dental Debriding Solution (EDDS) like desiccating action leading to denaturation and destabilization of plaque and mechanical removal of destabilized plaque through forceful rinsing actionMaterials and Methods25 extracted teeth, after routine debriding and cleaning, underwent standard biofilm incubation model over 4 days. Then samples were randomly divided into 5 groups of 5 teeth each, treated and stained with GUM®Red-Cote® plaque disclosing solution and imaged. Samples were subsequently treated with HYBENX® Oral Decontaminant. Group 1 samples were treated with a standardized “static” water dip exposure following biofilm incubation. Samples in Group 2 were given a standardized “dynamic” exposure to a dental high pressure air/water syringe for 20 s. Group 3 samples were exposed to a standardized “static” application of test agent (30 s dip rinse) followed by a standardized “static” water rinse (30 s dip rinse). Samples in Group 4 were given both the standardized “static” application of test formulation followed by the standardized “dynamic” exposure to a dental high pressure air/water syringe. Finally, samples in Group 5 were treated with a standardized “dynamic” application of test agent (20 s high pressure syringe at 10 ml/s) followed by the standardized “dynamic” exposure to a dental high pressure air/water syringe.ResultsThe MPM images demonstrated that the water dip treatment resulted in the persistence of an almost continuous thick layer of biofilm coverage on the tooth surface. Similarly, test agent dip treatment followed by water dip only removed a few patches of biofilm, with the majority of the tooth surface remaining covered by an otherwise continuous layer of biofilm. Samples exposed to air/water spray alone showed some disruption of the biofilm, leaving residual patches of biofilm that varied considerably in size. Test agent dip treatment followed by air/water spray broke up the continuous layer of biofilm leaving only very small, thin scattered islands of biofilm. Finally, the dynamic test agent spray followed by air/water spray removed the biofilm almost entirely, with evidence of only very few small, thin residual biofilm islands.ConclusionThese studies demonstrate that test agent desiccant effect alone causes some disruption of dental biofilm. Additional dynamic rinsing is needed to achieve complete removal of dental biofilm.

Computed tomography of the chest: I. Basic principles

### Key points The conventional chest radiograph superimposes a three-dimensional image onto a two-dimensional surface, so limiting its clinical usefulness. Since its introduction in 1971, X-ray computed tomography (CT) has rapidly evolved into an essential diagnostic imaging tool that forms a cross-sectional image, avoiding the super-imposition of structures that occurs in conventional chest imaging, with a >10-fold increase in attenuation sensitivity. Although CT imaging is reported by radiologists, it is important for both anaesthetists and intensivists to be able to interpret the scans, as reporting facilities may not be immediately available. Furthermore, the radiologist may not fully report all facets of a detailed scan and further information may be acquired by a physician with the ability to interpret CT scans. This is the first in a series of two articles written for anaesthetists and intensivists covering both thoracic anatomy and pathology as it relates to CT. A CT scanner makes many measurements, from different rotational angles, of X-ray attenuation ( weakening in force or intensity ) through the cross-sectional plane of the thorax. It then uses these data to reconstruct a digital representation of the cross-section with …

Application of Magnetic Particle Imaging to Pulmonary Imaging Using Nebulized Magnetic Nanoparticles

Purpose: To investigate the feasibility of applying magnetic particle imaging (MPI) to pulmonary imaging using nebulized magnetic nanoparticles (MNPs) and to quantify the mucociliary clearance in the lung, using small animal experiments. Materials and Methods: Intrapulmonary administration of MNPs was performed in seven-week-old male ICR (Institute of Cancer Research) mice (n = 8) using a nebulized microsprayer connected to a high-pressure syringe containing 50 μL of MNPs (500 mM Resovist®). We imaged the lungs using our MPI scanner 2.5 hours, 1 day, 3 days, and 7 days after the intrapulmonary administration of MNPs. The average MPI value was calculated by drawing a region of interest (ROI) on the lungs by taking the threshold value for extracting the contour as 20% of the maximum MPI value within the ROI. The MPI value was defined as the pixel value of the transverse image reconstructed from the third-harmonic signals. Mice were sacrificed immediately after the last MPI and X-ray CT studies on day 7, and 5 lobes of the lung in each mouse were extracted to confirm the accumulation of iron using Berlin blue staining. Results: We could visualize the distribution of MNPs in the lungs as positive contrast using MPI with use of nebulized MNPs. The presence of iron in the lung was confirmed by Berlin blue staining. The average MPI value decreased with time and tended to saturate. The clearance rate was calculated to be 0.505 day−1 from the time course of the average MPI value in the lungs. Conclusion: Our preliminary results suggest that MPI can be applied to pulmonary imaging by nebulizing MNPs and can be useful for quantifying the mucociliary clearance in the lung.

Compression mechanisms of unsaturated clay under high stresses

This paper investigates the compression behavior of unsaturated clay under mean stresses up to 160 MPa and different drainage conditions. A new isotropic pressure cell was developed that incorporates matric suction control using the axis-translation technique, and a high-pressure syringe pump operated in displacement-control mode was used to control the total stress and track specimen volume changes. In addition to presenting results from characterization tests on the cell, results from a series of isotropic compression tests performed on compacted clay specimens under drained and undrained conditions are presented. These results permit evaluation of the hardening mechanisms and transition points in the compression curve with increasing effective stress. As expected, specimens tested under undrained conditions were much stiffer than those tested under drained conditions. In the drained tests, the rate of compression was sufficient to permit steady-state dissipation of excess pore-water pressure except under the highest stress ranges. Suction-induced hardening was observed when comparing saturated and unsaturated specimens tested in the drained compression tests. In both the drained and undrained compression tests, the range of applied stresses was sufficient to cause collapse or dissolution of the air voids (pressurized saturation) and convergence of the virgin compression lines for unsaturated specimens with that measured for saturated specimens. A gradual transition to full-void closure was observed at high stresses when the compression curves were plotted on a natural scale, but the shapes of the compression curves at high stresses were not consistent with conventional soil mechanics models when plotted on a semilogarithmic scale. The results from this study provide insight into how constitutive models for unsaturated soils can be extended to high stress conditions for drained and undrained conditions.

Investigation on the optical scan condition for imaging of multi-slice spiral CT liver perfusion in rats

Background Multi-slice CT liver perfusion has been widely used in experimental studies of hemodynamic changes in liver lesions, and is usually performed as an adjunct to a conventional CT examination because of its high temporal and spatial resolution, simple protocol, good reproducibility, and ability to measure hemodynamic changes of liver tissues at the capillary level. Experimental rat models, especially those of induced liver cancer, are often used in studies of hemodynamic changes in liver cancer. Carcinogenesis in rats has a similar pathological progression and characteristics resembling those in human liver cancer; as a result, rat models are often used as ideal animal models in the study of human liver cancer. However, liver perfusion imaging in rats is difficult to perform, because rats' livers are so small that different concentrations, flow rates, and dose of contrast agents during the CT perfusion scanning can influence the quality of liver perfusion images in rats. The purpose of this study, therefore, was to investigate the optimal scan protocol for the imaging of hepatic perfusion using a deconvolution mathematical method in rats by comparing the results of rats in different injection conditions of the contrast agent, including concentration, rate and time. Methods Plain CT scan conditions in eighty 2-month-old male Wistar rats were 5.0 mm slice thickness, 5.0 mm interval, 1.0 pitch, 120 kV tube voltage, 60 mA tube current, 512×512 matrix, and FOV 9.6 cm. Perfusion scanning was carried out with different concentrations of diatrizoate (19%, 38%, 57%, and 76%), different injection rates (0.3 and 0.5 ml/s), and different injection times (1, 2-3, 4-5, and 6 seconds). The above conditions were randomly matched and adjusted to determine the best perfusion scan protocol. Three-phase contrast-enhanced scanning was performed after CT perfusion. Histological examination of the liver tissues with hematoxylin and eosin stains was done after CT scanning. Results When the concentration of the contrast agent was 19% or 38%, no pseudo-color map was created. The viscosity increased when the concentration of the contrast agent was 76%; so it is difficult to inject the contrast agent at such a high concentration. Also no pseudo-color map was generated when the injection time was short (1, 2-3, and 4-5 seconds) or the injection rate was low (0.3 ml/s). The best perfusion images and perfusion parameters were obtained during 50 seconds scanning. Each rat was given an injection of 57% diatrizoate at 0.5 ml/s via the tail vein using a high-pressure syringe for 6 seconds. The perfusion parameters included hepatic blood flow (HBF), hepatic blood volume (HBV), mean transit time (MTT) of the contrast agent, capillary permeability-surface area product (PS), hepatic arterial index (HAI), hepatic artery perfusion (HAP), and hepatic portal perfusion (HPP). All these parameters reflected the perfusion status of liver parenchyma in normal rats. Three phases of enhancement were modified according to the time-density curves (TDCs) of the perfusion imaging: hepatic arterial phase (7 seconds), hepatic portal venous phase (15 seconds), and a delayed phase (23-31 seconds). On examination by microscopy, the liver tissues were pathologically normal. Conclusions The appropriate protocol with multi-slice spiral CT liver perfusion reflected normal liver hemodynamics in rats. This study laid a solid foundation for further investigation of the physiological characteristics of liver cancer in a rat model, and was an important supplement to and reference for conventional contrast-enhanced CT scans.

Determination of polychlorinated biphenyls and organochlorine pesticides in small volumes of human blood by high-throughput on-line SPE-LVI-GC-HRMS

A fully automated and robust method featuring on-line solid-phase extraction (SPE) and large volume injection (LVI) gas chromatographic (GC) high resolution mass spectrometry (HRMS) is used to determine polychlorinated biphenyls (PCBs) and organochlorine pesticides, such as penta- and hexachlorobenzene (PeCBz, HxCBz), hexachlorocyclohexane isomers (HCH) and 4,4'-dichlorodiphenyldichloroethene (a metabolite of dichlorodiphenyltrichloroethane (DDT)), with only 200μl of human blood, serum or plasma. After spiking the sample with (13)C-labeled internal standards and precipitating the proteins, the sample is passed through a 10mm×2.0mm ID SPE cartridge filled with C18 material that adsorbs the analytes. After washing and drying, the cartridge is extracted with hexane/dodecane (99/1, v/v); the extract is directly injected into a LVI where GC/HRMS analysis follows. The fully automated system utilizes a robotic autosampler and a modular SPE system including two high-pressure syringe pumps, an automatic SPE cartridge exchanger unit and 6 switchable valves. All sample preparation steps are performed within 20min during the GC run of a previous sample, limiting the throughput with only the GC runtime. The contents are quantified using the isotope dilution method. Due to laboratory air contamination problems, we achieved LOQs of 0.017 (PeCBz), 0.009 (HxCBz), 0.007 (HCH), 0.016 (DDE), while for the six indicator PCBs, we achieved values of 0.030 (PCB-28), 0.044 (PCB-52), 0.024 (PCB-101), 0.009 (PCB-138), 0.015 (PCB-153) and 0.008 (PCB-180)μg/l serum. Under clean laboratory air conditions, these values may be improved. This method is recommended when high throughput is desirable and/or only small amounts of material are available, such as during studies involving children.

Clinical value of time-intensity curve analysis of hysterosalpingo-contrast-sonography in the diagnosis of women infertility due to tube obstruction

Objective To investigate the clinical value of hysterosalpingo-contrast-sonography (HyCoSy) with high-pressure syringe injection and time-intensity curve analysis in the diagnosis of women infertility due to tube obstruction.Methods Fifty-six women with infertility underwent HyCoSy with compressive injection of SonoVue with a balloon catheter and high-pressure syringe.Time-intensity curve based on Autotracking Contrast Quatification (ACQ) software was analyzed in all patients.The arrival time (AT) of microbubbles from uterine cavity to tube fimbria was analyzed between partially obstructed tube group and control group.Results The AT in the group of partially obstructed tubes was (3.49 ± 1.70) s,while the AT in the group of freely patent tubes was (1.14-± 0.37)s,there was statistical difference of AT between the group of partially obstructed tubes and the group of freely patent tubes (P =0.000).According to ROC results,the optimization point of AT was 1.65 s,the sensitivity,specificity,positive predictive value and negative predictive value were 92.6％,93.3％,96.2％ and 87.5％,respectively.Conclusions High-pressure syringe injection in HyCoSy is useful for regular administration and high image quality.The AT could be considered as the diagnostic indices in the evaluation of fallopian tube patency for infertile women. Key words: Ultrasonography; Microbubbles ; Infertility, female; Hysterosalpingography