人体静脉血样采集管的不同内表面状态对血小板活化的影响

目的 研究人体静脉血样采集管的不同内表面状态对血小板活化的影响.方法 用聚环氧烷-聚二甲基硅氧烷共聚物(L722)、硅烷偶联剂对塑料管(PET)和玻璃管制膜,对L722玻璃管、L722 PET管、玻璃管、PET管、硅烷偶联剂制膜玻璃管及聚丙烯管(PP)内表面进行接触角分析.用上述材料的血样采集管采集血液标本并在室温下滚动混匀孵育110～60 min.用流式细胞术(FCM)检测血小板激活标志物CD62p.结果 不同材质及表面处理血液采集管的内表面的接触角大小在一定程度上反映了血小板活化率,但并不呈线性关系.PET管经L722表面改性后表达CD62p阳性的活化血小板百分率由(37.4±14.8)%下降到(21.9±12.4)%.玻璃管对表达CD62p阳性的活化血小板百分率为(54.5±18.6)%,明显大于PET管.玻璃管制膜后对血小板的激活明显减少,用硅烷偶联剂制膜的玻璃管表达CD62p阳性的活化血小板百分率为(28.3±8.2)%,明显低于L722制膜玻璃管.用PET作为基体材料经过L722表面处理后对血小板活化明显低于L722制膜的玻璃管的(41.5 ±15.9)%和用硅烷偶联剂制膜的玻璃管的(22.0±12.8)%.不同管对血小板活化时间进程显示:60 min L722 PET管和聚丙烯管的血小板活化与30 min的结果差异无统计学意义.结论 不同材质及表面处理血液盛装管所导致的不同表面能状态对血小板活化的影响有明显差异,硅油表面处理能有效改善血液采集管的血液相容性.FCM检测CD62p是评价血液收集管材料介导的血小板活化的灵敏指标,对建立血液盛装材料表面处理模型及筛选临床应用材料具有重要意义.     

Evaluation of polyethylene terephthalate for ABO and Rh typing and alloantibody screening

BACKGROUND: For many years, hospitals and laboratories have used evacuated glass tubes for blood collection. To improve the safety of blood collection, plastic polyethylene terephthalate (PET) tubes (Vacutainer PLUS, Becton Dickinson) have been developed. The objectives of this study were to compare the accuracy of ABO grouping, Rh typing, and antibody screening of blood samples collected in plastic tubes with that in glass tubes and to determine if refrigerated blood samples collected in plastic tubes remained stable over a 28-day period. STUDY DESIGN AND METHODS: Samples were collected from 121 volunteers, at least 30 from each of the A, B, O, and AB blood groups, in four types of Vacutainer tubes: silica-coated plastic, K(2) EDTA plastic, uncoated glass, and K(2) EDTA glass. Samples from each tube were tested for ABO group and Rh type by use of the microtyping gel identification card system and the tube method. A three-cell antibody screen was performed by the microtyping gel card technique with a monospecific IgG reagent. Initial samples were tested within 3 hours of collection. Refrigerated samples were retested for ABO and Rh type and antibody screening 1, 2, 21, and 28 days later. Agreement between test results was determined by using Cohen's Kappa statistic. RESULTS: Complete agreement was observed between the ABO and Rh typing results in samples drawn into glass and plastic tubes of both the EDTA and nonanticoagulated type (kappa = 1.0). In retesting, there were no examples of a change in ABO or Rh type over the 28-day study period. Only two alloantibodies (1.7%) were identified in the 121 samples, and no difference was observed in alloantibody expression in either plastic or glass Vacutainer tubes over the 28-day study period. CONCLUSION: Samples collected into the PET serum or EDTA tubes provided accurate ABO and Rh typing results that remained consistent over a 28-day period. Samples collected in these tubes also appeared to enable accurate alloantibody identification. However, the number of alloantibodies identified in this study was small, and this result should be confirmed in a larger series.     

Stability of brain natriuretic peptide (BNP) in human blood samples.

Stability of immunoreactivity of human brain natriuretic peptide (BNP) in blood samples was investigated. After storage of the whole blood samples in the blood collecting tubes made of glass or polyethylene terephthalate (PET), residual immunoreactivity of BNP in the plasma was measured by sandwich radioimmunoassay for human BNP. BNP in the blood samples collected in the PET tubes were kept more stable than that in the glass tubes. The results suggested that commercially available PET tubes would enable more accurate BNP values and this would also help to simplify the sample preparation.     

Degradation of human brain natriuretic peptide (BNP) by contact activation of blood coagulation system

Brain natriuretic peptide (BNP) and atrial natriuretic peptide (ANP) were added to venous blood samples from healthy volunteers, and incubated in tubes made of various materials. The residual immunoreactivity was measured with radioimmunoassay for BNP and ANP. In blood samples stored in glass tubes, immunoreactivity of ANP was more stable than that of BNP. In siliconized glass or PET tubes, however, BNP immunoreactivity was more stable than ANP. The activation of blood coagulation factors was evaluated from the kallikrein activity in plasma. Kallikrein activity was increased in plasma stored in glass tube while it was negligible in plasma stored in siliconized glass or PET tubes. In kaolin-activated plasma, more rapid BNP degradation and higher kallikrein activity were observed. Our results indicated that the blood coagulation factors, especially kallikrein, played an important role in digestion of BNP.     

1999 ICP Distinguished Scientist Award. The history of positron emission tomography.

The history of Positron Emission Tomography (PET) is rich in technological achievements and advancements. The advancements that have benchmarked PET progress are the result of key components that include human intellect and passion for PET technology, relentless persuasion of key political forces to eliminate the barriers precluding PET usage, tireless efforts to raise awareness about PET and a crucial network of support throughout the PET community.This article sets forth a timeline of significant events that have contributed to the development of PET as it is known today. It introduces the earliest physicist and physician, for instance, who were responsible for the first medical applications for positron emitting radioisotopes using a simple brain probe that utilized coincidence to localize brain tumors. Additionally, it identifies landmark technological achievements that have helped pave the way to modern PET. This study includes historical accounts surrounding the use of the first human PET tomograph, discovery of the Bismuth Germanate (BGO) scintillator, development of the Fluorodeoxyglucose (FDG) PET method, the design of the first PET medical cyclotron with automated chemistry and operated by a PC and a technologist, Food and Drug Administration's approval of FDG, HCFA reimbursement, and the capacity of Lutetium Oxyorthosilicate (LSO) to produce a revolutionary advance in PET scanners.The main thrust of this article is to recognize via a timeline of PET accomplishments the noteworthy work of scientists, physicians and others who have been key players in various aspects of the continuous activity to move PET technology forward from invention to research, and to become a major clinical imaging modality.     

ISO15189认可过程中两种分离胶采样管的质量评价

目的探讨建立两种不同的分离胶采样管的质量评价方法。方法以硅化玻璃采血管为标准管,以两种分离胶采样管为测试管,随机收集50例患者血清,利用电化学发光、酶联免疫吸附法、反射发光法、免疫荧光法等方法定量或者定性检测血清中各种临床免疫、临床生化指标,并进行相应的统计分析。结果对于定量项目而言,两种分离胶采样管与标准管相比,检测结果比较差异无统计学意义(P0.05);对于定性项目而言,两种分离胶采样管与标准管相比,真阳性率和真阴性率比较差异无统计学意义(P0.05,K0.75),一致性较好。结论通过使用不同的检测方法和检测项目证明了分别采用两种分离胶采样管不会影响到检测结果的准确性和一致性,初步建立了ISO15189实验室认可过程中该实验室针对外部供应品的质量评价方法。     

STUDIES ON PNEUMOCOCCUS GROWTH INHIBITION : IV. A SIMPLIFIED AGITATOR FOR GROWTH INHIBITION TESTS WITH SERUM-LEUCOCYTE MIXTURES; AND CERTAIN MODIFICATIONS IN THE TECHNIQUE OF THE TEST.

A simplified and compact agitator for growth inhibition tests with serum-leucocyte mixtures has been described. Several modifications have been made as well in the technique of the test, which have eliminated occasional irregularities that necessitated discarding the results of the individual experiment. Such irregularities were found to be due chiefly to injury of the pneumococci brought about by prolonged suspension in gelatin-Locke''s solution which resulted in failure of the organisms to grow in the control serum-leucocyte tubes. This deterioration of the pneumococcus suspension may be greatly lessened or entirely prevented by the addition of a small quantity of a balanced phosphate mixture to the gelatin-Locke''s solution. The use of small tubes made of Pyrex glass has also eliminated the former, not infrequent, occurrence of early hemolysis which was sometimes intense enough to disturb the results of the test. It has been found that washed rabbit leucocytes, suspended in their homologous serum, may be kept in the ice box for as long a period as 2 days without showing any apparent diminution of their functional activity in the serum-leucocyte test.     

Adsorption of EGF receptor ligands to test tubes--a factor with implications for studies on the potency of these peptides.

Studies on the relative potency of ligands for the epidermal growth factor receptor are usually performed with highly purified ligand specimens. However, adsorption of ligands to glass and plastic surfaces may affect the results by reducing the ligand concentration in an unpredictable way. The aim of this study was to examine the adsorption of four epidermal growth factor (EGF) receptor ligands, EGF, transforming growth factor alpha (TGF-alpha), heparin binding-EGF (HB-EGF) and betacellulin, to commonly used test tubes of polyethylene, polystyrene and glass, respectively. The ligands were kept in a sodium phosphate buffer, both with and without 0.1% human albumin as carrier protein. Adsorption was examined after 20 minutes at room temperature as well as after overnight storage at 4 degrees C. The ligands were quantitated by ELISAs. In the buffer not containing 0.1% human albumin there was a marked adsorption, which differed both among the ligands and among the test tubes. After 20 minutes the ligand concentrations were reduced to 33-73% in polyethylene tubes, to 15-46% in polystyrene tubes and to 12-29% in glass tubes. The adsorption was even more pronounced after storage overnight. The use of 0.1% human albumin in the buffer solved the problem in polyethylene and polystyrene tubes, but not in glass tubes. The results demonstrate that adsorption to surfaces can be a significant problem for EGF receptor ligands and emphasize the need for controlling the growth factor concentration in the final experimental setting.     

Reviewing the effectiveness of tympanic thermometers

Tympanic thermometers have become a popular alternative to glass mercury thermometers for recording patients' temperatures. This article reviews studies that have been performed to audit their use in clinical practice. It examines the accuracy of tympanic thermometers and discusses ways to improve the use of this instrument and the implications for nursing practice.     

Feasibility of Sequential PET/MRI Using a State-of-the-Art Small Animal PET and a 1 T Benchtop MRI

Purpose

Combined PET/MRI studies receive increasing attention, as their combination allows deeper insight into disease progression. We evaluated a novel 1 T benchtop MRI scanner (1T-MRI) for its use in sequential PET/MRI studies.

Procedures

Phantom studies were performed, addressing the attenuation caused by the MRI coils. For in vivo studies, PET/MRI data acquired with the 1T-MRI were compared with data using a conventional small animal high-field MRI (7T-MRI) in combination with the same PET scanner.

Results

Phantom and in vivo measurements show that the animal beds have no negative impact on the PET scanner performance compared to the 7T-MRI animal bed. Representative images of various animal studies are shown, indicating a wide field for sequential PET-benchtop MRI applications.

Conclusion

Phantom and in vivo data indicate that sequential PET/MRI studies with this novel setup are comparable to sequential PET/MRI studies using a 7T-MRI in combination with a dedicated PET scanner.     

State of the Art in Cardiac Hybrid Technology: PET/MR

Simultaneous PET/MRI is an emerging technique combining two powerful imaging modalities in a single device. The wide variety of available tracers for perfusion and metabolic studies and the high sensitivity of positron emission tomography (PET) combined with the high spatial resolution and soft tissue contrast of magnetic resonance imaging (MRI) in depicting cardiac morphology and function as well as MRI’s absence of ionizing radiation makes PET/MRI very attractive to radiologists and clinicians. Nevertheless, PET/MR scientific and clinical promise is to be considered in the context of numerous technical challenges that hinder its use in the clinical setting. For example, in order for a PET system to work correctly within an MR field, major changes are required to the photon detection chain such as the elimination of photomultiplier tubes, etc. Another significant limitation of PET/MRI is the lack of an electron density map (as is the case with PET-CT) that can be readily obtained from MRI (the latter measures proton not electron density) and used to correct PET data for attenuation. Moreover, as with PET-CT, cardiac and respiratory motions cause image degradations that affect image quality and accuracy both in static and dynamic PET imaging. As a result, overcoming these (and other) technical limitations is a very active area of research both in academic institutions as well as industry. In this paper, we review recent literature on cardiac PET/MRI, present the state-of-the-art of this technology, and explore promising preclinical and clinical cardiac applications where PET/MRI could play a substantial role.     

PET scanners dedicated to molecular imaging of small animal models.

The dramatic advances of biological research in recent years that have focused on the molecular basis of how systems of the body (e.g. cells, organs and the whole organism) function, have increased the need for molecular imaging instrumentation. Of the several imaging modalities available today applied for in vivo studies of research animals, positron emission tomography (PET) is a technique that permits non-invasive use of positron labeled molecular imaging probes to image and assay biochemical processes of cellular function in the living subject. Imaging can be performed repeatedly before and after interventions and therefore allows the use of each animal as its own control. Many different positron labeled compounds have been and continue to be synthesized as probes that target a range of molecular targets within specific biochemical pathways. These molecular imaging probes are used in extremely low mass amounts, such that biological processes involving compounds in nanomolar concentration or lower can be imaged without disturbing the process. Biological processes from receptors and synthesis of transmitters in cell communication pathways, to metabolic processes and gene expression can be imaged. In the past, PET in animal research has been used extensively for studies of primates and larger animals. In recent years, the development of new detector technology has lowered the limits of spatial resolution. This has made it possible to use PET scanning for the study of the most important modern molecular biology model, the laboratory mouse. This paper presents some of the challenges facing small animal PET technology, provides an overview of the development of small animal PET systems, and discusses the current state of the art technology, some of its applications, as well as some future directions.     

Update for nurse anesthetists--part 3--cyclodextrin introduction to anesthesia practice: form, function, and application

Cyclodextrins, some of the select molecules exhibiting properties that are beneficial across multiple industries, are naturally occurring cyclical oligosaccharides with a lipophilic inner cavity and a hydrophilic exterior. These characteristics enable cyclodextrins to surround and bind lipophilic molecules while maintaining aqueous solubility. Agrochemistry, analytical chemistry, food, nutraceutical, and pharmaceutical industries have benefited and continue to benefit from these unique molecular properties. Though known and studied for more than 100 years, cyclodextrins have only recently been explored for specific application to anesthesia. Numerous studies exploring cyclodextrin-improved anesthetic delivery are underway. This new class of enabling molecules will enter the anesthetic arena and will require an understanding of their form, function, and application. This knowledge will facilitate anesthesia providers' optimal use of these unique molecules and the safety and efficacy associated with them.     

The physiological and pathophysiological roles of neuronal histamine: an insight from human positron emission tomography studies

Histamine neurons are exclusively located in the posterior hypothalamus, and project their fibers to almost all regions of the human brain. Although a significant amount of research has been done to clarify the functions of the histaminergic neuron system in animals, a few studies have been reported on the roles of this system in the human brain. In past studies, we have been able to clarify some of the functions of histamine neurons using different methods, such as histamine-related gene knockout mice or human positron emission tomography (PET). The histaminergic neuron system is known to modulate wakefulness, the sleep-wake cycle, appetite control, learning, memory and emotion. Accordingly we have proposed that histamine neurons have a dual effect on the CNS, with both stimulatory and suppressive actions. As a stimulator, neuronal histamine is one of the most important systems that stimulate and maintain wakefulness. Brain histamine also functions as a suppressor in bioprotection against various noxious and unfavorable stimuli of convulsion, drug sensitization, denervation supersensitivity, ischemic lesions and stress susceptibility. This review summarizes our works on the functions of histamine neurons using human PET studies, including the development of radiolabeled tracers for histamine H1 receptors (H1R: (11)C-doxepin and (11)C-pyrilamine), PET measurements of H1R in depression, schizophrenia, and Alzheimer's disease (AD), and studies on the sedative effects of antihistamines using H(2)(15)O and H1R occupancy in the human brain. These molecular and functional PET studies in humans are useful for drug development in this millennium.     

Gastrostomy tubes: facts, fallacies, fistulas, and false tracts.

The first successful gastrostomy was performed 130 years ago. Although it is difficult to ascertain the exact number of gastrostomy or jejunostomy tubes placed annually in the United States, it is estimated approximately 230,000 gastrostomy procedures were performed in U.S. hospitals in 2001. Of these, 11,000 were performed in children. Despite the many years gastrostomy tubes have been in use, they are not free from complications. The purpose of this article is to review the authors' experience with pediatric patients who have undergone radiographic placement of gastrostomy or jejunostomy tubes.     

The current state,challenges and perspectives of MR-PET

Following the success of PET/CT during the last decade and the recent increasing proliferation of SPECT/CT, another hybrid imaging instrument has been gaining more and more interest: MR-PET. First combined, simultaneous PET and MR studies carried out in small animals demonstrated the feasibility of the new approach. Concurrently, some prototypes of an MR-PET scanner for simultaneous human brain studies have been built, their performance is being tested and preliminary applications have already been shown. Through this pioneering work, it has become clear that advances in the detector design are necessary for further optimization.Recently, the different issues related to the present state and future prospects of MR-PET were presented and discussed during an international 2-day workshop at the Forschungszentrum Jülich, Germany, held after, and in conjunction with, the 2008 IEEE Nuclear Science Symposium and Medical Imaging Conference in Dresden, Germany on October 27–28, 2008. The topics ranged from small animal MR-PET imaging to human MR-BrainPET imaging, new detector developments, challenges/opportunities for ultra-high field MR-PET imaging and considerations of possible future research and clinical applications. This report presents a critical summary of the contributions made to the workshop.     

Drug development for neurodegenerative diseases: role of PET

There are few relevant animal models for neurodegenerative diseases to be used for human drug development. Most current drugs for neurodegenerative diseases act through different neurotransmitter systems. Positron emission tomography (PET) is a unique tool in the study of neurodegenerative diseases as it enables quantitative measurements of oxygen consumption, blood flow, energy metabolism and functioning of various neurotransmitter systems. There are several possibilities in the use of PET in drug development. It is possible to radiolabel the drug itself or to study the effect of an unlabelled drug on blood flow, energy metabolism or function of neurotransmitter systems. All these approaches have been used in drug development for neurodegenerative diseases. However, in spite of the important role of PET in pathophysiological studies of neurodegenerative diseases, thus far the versatile possibilities of PET in drug development for neurodegenerative diseases have not been fully exploited.     

A new plastic evacuated tube with plasma separator

A new plastic-walled, evacuated blood collection tube (Terumo Venoject II) with plasma separator was evaluated for characteristics related to the use of plastic in place of glass. Plastic tubes were highly resistant to breakage through handling mishaps or failure during centrifugation. Higher centrifugation speed (13,600g) was well tolerated, and centrifugation times as short as 3 minutes at 13,600g effectively cleared plasma of cellular components, at high plasma yield. Plastic tubes were nearly completely combustible under incineration conditions commonly used for medical waste, and plastic tubes effectively retained vacuum during the typical shelf life of evacuated blood collection tubes. Collection of carbamezepine specimens in plastic tubes decreased levels an average of 6.8% compared to a heparinized glass tube control under conditions approximating routine use; levels of other drugs (phenytoin, phenobarbital, valproic acid, theophylline, and cyclosporine) were less significantly affected. This modest decrease appeared to result from a combination of an immediate interaction with the plastic surface of the tubes and a time-dependent interaction with the olefin-based separator. Modest but clear benefits including reduction in specimen breakage, reduced centrifugation time and reduced solid waste after incineration derive from the use of plastic in place of glass in evacuated blood collection tubes.©1995 wiley-Liss, inc.     

Anatomy,Functionality, and Neuronal Connectivity with Manganese Radiotracers for Positron Emission Tomography

Purpose

Manganese ion has been extensively used as a magnetic resonance imaging (MRI) contrast agent in preclinical studies to assess tissue anatomy, function, and neuronal connectivity. Unfortunately, its use in human studies has been limited by cellular toxicity and the need to use a very low dose. The much higher sensitivity of positron emission tomography (PET) over MRI enables the use of lower concentrations of manganese, potentially expanding the methodology to humans.

Procedures

PET tracers manganese-51 (Mn-51, t_1/2?=?46 min) and manganese-52 (Mn-52, t_1/2?=?5.6 days) were used in this study. The biodistribution of manganese in animals in the brain and other tissues was studied as well as the uptake in the pancreas after glucose stimulation as a functional assay. Finally, neuronal connectivity in the olfactory pathway following nasal administration of the divalent radioactive Mn-52 ([⁵²Mn]Mn²⁺) was imaged.

Results

PET imaging with the divalent radioactive Mn-51 ([⁵¹Mn]Mn²⁺) and [⁵²Mn]Mn²⁺ in both rodents and monkeys demonstrates that the accumulation of activity in different organs is similar to that observed in rodent MRI studies following systemic administration. Furthermore, we demonstrated the ability of manganese to enter excitable cells. We followed activity-induced [⁵¹Mn]Mn²⁺ accumulation in the pancreas after glucose stimulation and showed that [⁵²Mn]Mn²⁺ can be used to trace neuronal connections analogous to manganese-enhanced MRI neuronal tracing studies.

Conclusions

The results were consistent with manganese-enhanced MRI studies, despite the much lower manganese concentration used for PET (100 mM Mn²⁺ for MRI compared to ~?0.05 mM for PET). This indicates that uptake and transport mechanisms are comparable even at low PET doses. This helps establish the use of manganese-based radiotracers in both preclinical and clinical studies to assess anatomy, function, and connectivity.

     

Drug development, radiolabelled drugs and PET

Positron emission tomography (PET) provides noninvasive in vivo quantitative pharmacokinetic and pharmacodynamic information on novel and established drugs. Because only very low amounts of the (potential) drug have to be administered, far below toxicity levels, human studies can be carried out even before the drug is entered in phase I studies. Such studies can provide cost-effective predictive toxicology data and information on the metabolism and mode of action of drugs. PET is also very useful in the study of the metabolic consequences of gene expression or gene defects. In the last decade, several models using genetically engineered small animals have been developed. The study of these animals with high-resolution small animal PET cameras provides new opportunities in drug development. Especially valuable is the contribution of PET in bridging the gap between molecular biology, basic pathology and the design of a new generation of drugs.