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Conductivity tensor of striped quantum hall phases. PHYSICAL REVIEW LETTERS 2000; 84:2937-2940. [PMID: 11018980 DOI: 10.1103/physrevlett.84.2937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/1999] [Indexed: 05/23/2023]
Abstract
We study the transport properties of pinned striped quantum Hall phases. We show that, under quite general assumptions, the macroscopic conductivity tensor satisfies a semicircle law. In particular, this result is valid for both smectic and nematic stripe phases, independent of the presence of topological and orientational defects such as dislocations and grain boundaries. As a special case, our results explain the experimental validity of a product rule for the dissipative part of the resistivity tensor, which was previously derived by MacDonald and Fisher (cond-mat/9907278) for a perfect stripe structure.
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102
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Abstract
A ribozyme (RZ) gene targeting c-myc mRNA was synthesized and cloned. Cleavage reaction showed that cleavage of the RZ was efficient and specific. The RZ gene-containing retrovirus vector pDOR-RZ was transfected into HCC-9204 hepatoma cells, which constitutively express high levels of c-myc using Lipofectamine. Positively transfected cells were selected using G418. In situ hybridization showed that both pDOR-RZ and pDOR vectors had been integrated into the chromosome of HCC-9204 cells. Dot blot hybridization indicated that expression of the RZ was only evident in pDOR-RZ-transfected HCC-9204 cells. Avidin-biotin complex enzyme-linked immunosorbent assay showed that c-myc expression was down-regulated. Chromatin aggregation into compact masses, cytoplasmic vacuole degeneration, and blurring of cytoplasm structure were observed by transmission electron microscopy in HCC-9204-RZ cells. These results suggest that the use of a c-myc mRNA cleaving enzyme could be most effective in tumor cells that are highly proliferative and constitutively express high levels of c-myc.
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Nitric oxide stimulates tyrosine phosphorylation of focal adhesion kinase, Src kinase, and mitogen-activated protein kinases in murine fibroblasts. Free Radic Biol Med 2000; 28:174-82. [PMID: 11281284 DOI: 10.1016/s0891-5849(99)00233-6] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Nitric oxide (NO) can participate in cellular signaling. In this study, monoclonal antibodies against proteins from the growth factor-mediated signalling pathway were used to identify a set of 126-, 56-, 43-, and 40-kDa proteins phosphorylated on tyrosine at NO stimulation of murine fibroblasts overexpressing the human epidermal growth factor receptor. The band corresponding to the 126-kDa protein was FAK. The 56-kDa protein was Src kinase, and the doublet 43- and 40-kDa protein corresponded to the extracellular-regulated MAP kinases (ERK1/ERK2). The effects of NO on focal adhesion complexes were also investigated. FAK was constitutively associated with the adapter protein Grb2 in HER14 cells. Treatment of the cells with the NO donor, sodium nitroprusside, or with EGF did not change this association. We also detected a basal constitutive association of Src kinase with FAK in HER14 cells. In NO-treated cells, this association was stimulated. The doublet 43/40-kDa protein was identical to the ERK1/ERK2 MAP kinases. NO stimulated an increase in ERK1/ERK2 phosphorylation as assessed by a shift in its eletrophoretic mobility and by increased phosphotyrosine immunoreactivity. Furthermore, NO-dependent activation of ERK1/ERK2 depended on the intracellular redox status. Inhibition of glutathione synthesis was necessary to promote activation of the kinases.
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104
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Dissipationless transport in low-density bilayer systems. PHYSICAL REVIEW LETTERS 2000; 84:139-142. [PMID: 11015854 DOI: 10.1103/physrevlett.84.139] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/1999] [Indexed: 05/23/2023]
Abstract
In a bilayer electronic system the layer index may be viewed as the z component of an isospin- 1 / 2. An XY isospin-ordered ferromagnetic phase was observed in quantum Hall systems and is predicted to exist at zero magnetic field at low density. This phase is a superfluid for opposite currents in the two layers. At B = 0 the system is gapless but superfluidity is not destroyed by weak disorder. In the quantum Hall case, weak disorder generates a random gauge field which probably does not destroy superfluidity. Experimental signatures include Coulomb drag and collective mode measurements.
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BBA fallout. Suppliers feel the pinch. HOSPITALS & HEALTH NETWORKS 2000; 74:28. [PMID: 11387743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
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106
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Abstract
BACKGROUND Immediate-type allergies to bumblebee stings occur infrequently. Previous studies have demonstrated a high degree of cross-reactivity between honeybee venom (HBV) and bumblebee venom (BBV). It has been proposed that venom immunotherapy (VIT) with HBV is a therapeutic alternative for patients with BBV allergy. METHODS AND RESULTS We present two cases of occupational immediate-type allergies to BBV. Although both nonatopic patients had a negative personal history of previous allergic reactions to honeybee sting, specific IgE antibodies and a positive intradermal reaction to HBV were detected. Despite VIT with HBV, the two developed another severe allergic reaction after incidental bumblebee stings. VIT with BBV, using in one patient a rush protocol and in the other a "conventional" regimen, with escalating doses of 0.01-100 microg of BBV, was performed. Before and during the VIT, the course of IgE and IgG specific antibodies to BBV was analyzed, demonstrating a significant decrease of BBV-IgE and an increase of BBV-IgG. The effectiveness of the treatment was also proven by an in-hospital sting challenge with a live bumblebee. CONCLUSIONS Our data demonstrate that cross-immunotherapies with HBV do not protect BBV-allergic patients sufficiently. We conclude that BBV-allergic patients should be treated with BBV. A "rush" VIT with BBV is a safe alternative to a "conventional" protocol.
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Bioterrorism. HOSPITALS & HEALTH NETWORKS 2000; 74:58-60. [PMID: 11387750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
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A comparative study of the postoperative allogeneic blood-sparing effect of tranexamic acid versus acute normovolemic hemodilution after total knee replacement. Anesth Analg 1999; 89:1382-7. [PMID: 10589612 DOI: 10.1097/00000539-199912000-00010] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
UNLABELLED Both acute normovolemic hemodilution (NVHD) and tranexamic acid (TA) are potentially useful allogeneic blood conservation strategies after total knee replacement. However, the relative efficacy of these blood-sparing techniques is unknown. Therefore, to compare the postoperative allogeneic blood sparing of NVHD and TA after total knee replacement, we investigated 40 patients in a prospective, single-blinded study protocol. In Group TA, 30 min before deflating the limb tourniquet, an IV infusion of TA, 15 mg/kg, was administered over a 30-min period. Thereafter, a constant IV infusion of 10 mg x kg(-1) x hr(-1) was administered until 12 h after deflation of the limb tourniquet. Before induction of anesthesia, NVHD patients were bled to a target hematocrit of approximately 28%. Intravascular blood volume was maintained with lactated Ringer's solution. All autologous blood was transfused at the end of the surgery. Postoperatively, hematocrit was measured daily. In all cases, a hematocrit <27% was the postoperative transfusion trigger. Before discharge, deep vein thrombosis was excluded by Echo Doppler. Three months after surgery, the incidence of delayed thromboembolic events was assessed. The two groups were demographically comparable. In Group NVHD, 843 mL+/-289 of autologous blood was removed. Despite autologous blood transfusion, during the early postoperative period and until the third postoperative day, the NVHD group had significantly (P < 0.01) lower mean hematocrits when compared with the TA group. Thereafter, because of a significantly (P < 0.0008) greater allogeneic blood requirement in the NVHD group, no statistically significant difference in mean hematocrit recordings was noted among the groups. Blood accumulation in the surgical drain 12 h postoperatively, was significantly (P < 0.0008) higher in the NVHD group (259 mL+/-156) when compared with the TA group (110 mL+/-62). Significantly (P < 0.0008) more allogeneic blood was transfused in the NVHD group (19 U/13 patients) when compared with the TA group (2 U/2 patients). No abnormal Echo Doppler studies were reported. During the 3-mo follow-up period, a deep vein thrombosis and pulmonary embolus were documented in one patient in the NVHD group. We conclude that perioperative hemodynamic stability and allogeneic blood sparing is superior after tranexamic acid administration when compared with normovolemic hemodilution. IMPLICATIONS For total knee replacement, when compared with normovolemic hemodilution, tranexamic acid administration is associated with superior perioperative hemodynamic stability and allogeneic blood sparing.
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Abstract
Children's medical emergencies occur around the clock. In years past, the emergency department, open 24 hours a day, was a familiar site for treating these emergencies. However, in today's health care environment, the scenario can be more confusing. As many families move from a fee-for-service system into a managed care organization (MCO), they may be unclear about what they should do in an emergency involving their child. MCOs want to provide appropriate care, and at the same time, operate within a system designed to contain costs through the establishment of effective health care delivery systems. Providers of emergency services, including specialists in pediatric medicine and emergency medical services responders, also must contend with a different set of problems, including administrative entanglements and concerns about reimbursement for their services. This article continues the white paper series by the Emergency Medical Services for Children Managed Care Task Force.
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Abstract
BACKGROUND Stroke occurs in 1% to 7% of heart surgery. Aortic arch atherosclerosis is a risk factor for intraoperative stroke, and endarterectomy has been proposed to prevent stroke during heart surgery in patients with arch atheromas. METHODS AND RESULTS Intraoperative transesophageal echocardiography was performed in 3404 patients undergoing heart surgery between 1990 and 1996. Use of transesophageal echocardiography was unselected and based on equipment availability. Aortic arch atheromas (>/=5 mm, or mobile) were seen in 268 (8%) patients. They were evaluated for intraoperative stroke (confirmed by a neurologist and cerebral infarction on computed tomography or magnetic resonance imaging). Arch endarterectomy was performed in 43 patients as an adjunct to their cardiac procedure in an attempt to prevent intraoperative stroke. The intraoperative stroke rate in all 268 patients with atheromas was high (15.3%). On univariate analysis, age, previous stroke, and arch endarterectomy were significantly associated with intraoperative stroke. On multivariate analysis, age (odds ratio 3.9, P =.01) and arch endarterectomy (odds ratio 3.6, P =.001) were independently predictive of intraoperative stroke. Mortality rate in all 268 patients was high (14.9%). These patients with atheromas also had a long recovery room, intensive care unit, and total hospital length of stay (48 days). CONCLUSIONS Patients with protruding aortic arch atheromas are at high risk for intraoperative stroke, significant and multiple morbidity, prolonged hospital stay, and death resulting from heart surgery. Aortic arch endarterectomy is strongly associated with intraoperative stroke; its use should be carefully considered in light of these results.
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Abstract
The objective of this study was to identify a parsimonious set of questions that has high sensitivity and specificity for screening for individuals with multiple chemical sensitivity (MCS) syndrome. We performed a cross-sectional survey using a case-control design. Subjects were derived from patients seen at an academically based Occupational and Environmental Medicine Clinic. Cases consisted of patients who fulfilled the Cullen definition for MCS. Controls were patients who had diagnoses excluding MCS and asthma and who were matched to cases by age and sex. Cases and controls filled out a screening questionnaire that, among things, elicited responses as to whether and how subjects reacted to 122 different types of environmental exposures. Data from 44 pairs of cases and controls were available for analysis. The average age of cases was 50.2 years, and 91% was female. Among cases, the most common exposure that was purported to incite MCS was 'indoor air quality contaminants (unspecified)' (59%), followed by solvents (27.3%). After randomly excluding five cases and controls, a stepwise selection procedure for two-group discriminant analysis revealed that the main contributors to the discrimination of the remaining cases and controls were self-reported reactions to copy machine emissions, marking pens, aftershave, window cleaner, nylon fabric, pine-scented products, and rayon material. When a positive response to these factors was used as the sole method for discriminating cases from controls, only one of 41 cases was misclassified as a control while none of the controls was misclassified as a case. When the same method was applied to the five excluded cases and five excluded controls, only one of the five cases was misclassified while none of the five controls was misclassified as a case. Among patients with MCS defined by the Cullen criteria in this clinical setting, having a reaction to these seven common potential exposures comprised a parsimonious set of factors that discriminated between MCS patients and age- and sex-matched normal controls. These questions may have utility in screening for individuals with MCS in general population survey studies.
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The built environment as a component of quality care: understanding and including the patient's perspective. THE JOINT COMMISSION JOURNAL ON QUALITY IMPROVEMENT 1999; 25:352-62. [PMID: 10412082 DOI: 10.1016/s1070-3241(16)30450-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Although there has been little systematic assessment of how the built environment of health care facilities affects the quality of care, the built environment is a major element of structure of care--one of three facets of quality. Yet in contrast to the growing trend of using consumer perceptions of both processes and outcomes of care in QI activities, quality assessments of the structure of care do not currently rely on patient feedback. PURPOSE OF PROJECT: During the initial phase of a multiphase project, nine focus groups were conducted in 1997 to identify the salient dimensions of experience from the patient's perspective. The content of these focus groups guided the development of assessment tools in the second phase of the project, which began in February 1998. FINDINGS Participants in three focus groups that were held in each of three settings--ambulatory care, acute care, and long term care--described in detail a variety of reactions to the built environment. Analysis revealed eight consistent themes in what patients and family member consumers look for in the built environment of health care. In all three settings, they want an environment, for example, that facilitates a connection to staff and caregivers, is conducive to a sense of well-being, and facilitates a connection to the outside world. DISCUSSION Data derived from the focus group research has guided the development of quantitative survey and assessment tools. For each setting, patient-centered checklists and questionnaires are designed to help institutions set priorities for the improvement of facility design from the patient's perspective.
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Reduce the risk. Identify your service's risk for TB exposure and protect providers by utilizing personal protective equipment and other technologies. JEMS : A JOURNAL OF EMERGENCY MEDICAL SERVICES 1999; 24:S10-1. [PMID: 10538551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
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115
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Quality care begins with patient-friendly environments. HEALTH FORUM JOURNAL 1999; 42:53-4. [PMID: 10539025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
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116
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The isoprostanes: novel prostaglandin-like products of the free radical-catalyzed peroxidation of arachidonic acid. J Biomed Sci 1999; 6:226-35. [PMID: 10420080 DOI: 10.1007/bf02253564] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The isoprostanes (IsoPs) are a unique series of prostaglandin-like compounds formed in vivo from the free radical-catalyzed peroxidation of arachidonic acid. This review summarizes our current knowledge regarding these compounds. Novel aspects of the biochemistry and bioactivity of IsoPs are detailed and methods by which these compounds are analyzed are discussed. A considerable portion of this review deals with the utility of measuring IsoPs as markers of oxidant injury in human diseases particularly in association with risk factors that predispose to atherosclerosis, a condition in which excessive oxidative stress has been causally implicated.
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117
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Development of a brief questionnaire for screening for multiple chemical sensitivity syndrome. Toxicol Ind Health 1999. [DOI: 10.1191/074823399678846952] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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118
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Clastogenic factors: biomarkers of oxidative stress of potential utility in the clinical chemistry laboratory. ANNALS OF CLINICAL AND LABORATORY SCIENCE 1999; 29:134-9. [PMID: 10219701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
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119
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Abstract
Many imaging systems produce pictures by the superimposition of two fields of frames of interlaced sequences. Pictures obtained in this way, which are termed composite frames, are severely degraded if relative motion between the camera and the scene occurs. In the presence of motion the composite frame is affected by two types of distortion: the edge staircase effect that is due to the fact that objects appear at different positions in successive fields and motion blur that is due to scene motion during each field exposure. Motion-deinterlacing methods previously proposed to recover the staircase effect neglect motion blur. However, motion blur may be significant, especially in systems designed for low-intensity radiometric imaging that use long exposures or even in short-exposure systems that happen to be in moving vehicles such as tanks, planes, ships, etc. We introduce an algorithm for the restoration of the two types of distortion in a composite frame degraded by linear uniform motion.
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120
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Abstract
Mechanical vibrations are often the principal cause of image degradation. Low temporal-frequency mechanical vibrations involve random image degradation that depends on the instant of exposure. Exact restoration requires the calculation of a specific filter unique to each vibrated image. To calculate the restoration filter for each image, one needs the specific optical transfer function unique to the motion in the image. Therefore the instant of exposure and the motion function have to be measured or estimated by some other means. We develop a restoration filter for individual images blurred randomly by low-frequency mechanical vibrations. The filter is independent of the instant of exposure. The filter is designed to give its best performance averaged over a complete ensemble of vibrated images. Although when applying the new filter to any vibrated image the restoration achieved is slightly poorer than that achieved with an exact filter unique to the specific motion function, the new filter has the advantage of simplicity.
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Abstract
The development of a specific, reliable and noninvasive method for measuring oxidative stress in humans is essential for establishing the role of free radicals in human diseases. Currently, accurate techniques to assess oxidant injury in vivo are extremely limited although a number of approaches are being investigated. Of these, the measurement of specific products of nonenzymatic lipid peroxidation, the F2-isoprostanes (F2-IsoPs), appears to be a more accurate marker of oxidative stress in vivo in humans than other available methods. The purpose of this brief review is to acquaint the reader with the IsoPs from a biochemical perspective and to provide information regarding the utility of quantifying these compounds as indicators of oxidant stress.
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Impaired production of nitric oxide, superoxide, and hydrogen peroxide in glucose 6-phosphate-dehydrogenase-deficient granulocytes. FEBS Lett 1998; 436:411-4. [PMID: 9801159 DOI: 10.1016/s0014-5793(98)01174-0] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Since the generation of superoxide and hydrogen peroxide by NADPH oxidase and nitric oxide (NO) by NO synthase (NOS) in granulocytes is NADPH-dependent, we investigated the production of NO, superoxide and H2O2 in glucose 6-phosphate dehydrogenase (G6PD)-deficient human granulocytes. Our results showed that upon stimulation with either 5 microg/ml of lipopolysaccharide (LPS) or 10 microM of phorbol 12-myristate 13-acetate (PMA), the production of nitrite in normal granulocytes was elevated, 252 +/- 135% and 239 +/- 72%, respectively, compared to the resting stage. In contrast, G6PD-deficient granulocytes did not produce more nitrite upon stimulation with either LPS or PMA compared to the resting stage. Western blot analysis indicated a normal expression pattern of inducible NOS in G6PD-deficient granulocytes. In addition, the production of H2O2 and superoxide was also significantly impaired in G6PD-deficient granulocytes compared to control cells. These data demonstrate that G6PD deficiency causes an impairment in the production of NO, superoxide and H2O2.
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International population movements and public health in the Mekong region: an overview of some issues concerning mapping. THE SOUTHEAST ASIAN JOURNAL OF TROPICAL MEDICINE AND PUBLIC HEALTH 1998; 29:201-12. [PMID: 9886100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Geographical Information Systems (GIS) have many important applications in local, regional and global situation analysis, especially in relation to planning and implementation thereof. The complex issues involved in population movement between neighboring countries offer a good example of the assistance that GIS applications can provide to transborder public health planning. The Greater Mekong Subregion (GMS) involves 6 countries, among which greatly increased population movement is occurring for a variety of reasons. This movement carries with it high risks of disease dispersal and thus presents a major challenge to disease control. This paper addresses the questions of sources, access and presentation of a wide variety of data that is needed by planners to develop more appropriate cooperative approaches to public health management in the GMS, with the main focus on contributions from mapping.
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Transesophageal echocardiography in a case of cardiac compression: was it therapeutic? J Am Soc Echocardiogr 1998; 11:494-6. [PMID: 9619625 DOI: 10.1016/s0894-7317(98)70033-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Cardiac compression is a potentially life-threatening complication of heart surgery. This syndrome often has atypical manifestations, challenging our ability to make a rapid diagnosis and to institute emergent, life-saving treatment. We recently evaluated one such patient who showed cardiac compression caused by an unusual paracardiac mass. The addition of transesophageal echocardiography to the usual transthoracic study may have played more than just a diagnostic role in this case.
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Exposed! New protocols for post-HIV exposure. JEMS : A JOURNAL OF EMERGENCY MEDICAL SERVICES 1997; 22:70-2, 74-5. [PMID: 10174824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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127
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Abstract
Alendronate (4-amino-1-hydroxybutylidene-1,1-bisphosphonate) is a potent bisphosphonate that inhibits osteoclastic bone resorption and has proven effective for the treatment of osteoporosis. Its molecular mechanism of action, however, has not been defined precisely. Here we report that alendronate is a potent inhibitor of the protein-tyrosine-phosphatase-meg1 (PTPmeg1). Two substrates were employed in this study: fluorescein diphosphate and the phosphotyrosyl peptide src-pY527. With either substrate, alendronate was a slow binding inhibitor of PTPmeg1. Among the other bisphosphonates studied, alendronate was more potent and selective for PTPmeg1. The hydrolysis of fluorescein diphosphate by PTP epsilon and PTPmeg1 was sensitive to alendronate, with IC50 values of less than 1 microM; PTPsigma, however, under the same conditions, was inhibited by only 50% with 141 microM alendronate. Similarly, with the src-pY527 substrate, alendronate inhibition was also PTP dependent. Alendronate inhibited PTPmeg1 with an IC50 value of 23 microM, PTPsigma with an IC50 value of 2 microM, and did not inhibit PTP epsilon at concentrations up to 1 mM. The alendronate inhibition of these three PTPs and two substrates is consistent with the formation of a ternary complex comprised of enzyme, substrate, and inhibitor. PTP inhibition by hisphosphonates or vanadate was diminished by the metal chelating agent EDTA, or by the reducing agent dithiothreitol, suggesting that a metal ion and the oxidation of a cysteine residue are required for full inhibition. These observations show substrate- and enzyme-specific PTP inhibition by alendronate and support the possibility that a certain PTP(s) may be the molecular target for alendronate action.
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Abstract
Sublytic levels (microM) of hemin destabilized RBC membrane as indicated by ghost fragmentation pattern using a laser viscodiffractometer. Furthermore, electron microscopic study shows that 5 microM of hemin induced echinocytic transformation whereas higher hemin concentration (40 microM) induced spherocytic transformation. In addition, hemin oxidized sulfhydryl groups in a dose dependent fashion and Electron Spin Resonance study suggests that such oxidation may involve a thiyl radical. Moreover, sulfhydryl compounds enhanced hemin-induced lipid peroxidation. Desferroxamine could prevent hemin-induced sulfhydryl oxidation as well as hemin-induced decrease in membrane stability. In contrast, vitamin E could effectively prevent hemin-induced lipid peroxidation but could not prevent hemin-mediated membrane destabilization.
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Abstract
Strand breakage of supercoiled pBR322 DNA by a Fenton system is increased in the presence of palladium or platinum (Pt) ions. Neither Pd nor Pt ions can substitute for iron in the Fenton system. We have obtained several lines of evidence that Pd and Pt ions in the presence of a Fenton system can augment the production of OH., as monitored by a spectrophotometric method quantifying hydroxylated salicylate or by a fluorometric method quantifying catechol production. Furthermore, the promoting effect of both metal ions on OH. production was substantiated by the identification of multiple hydroxylated products of salicylate [2,3-dihydroxybenzoate (A), 2,5-dihydroxybenzoate (B), and catechol (C)] using HPLC. The concentrations of A, B, and C produced in the control were 4.5, 8.0, and 2.0 microM, respectively; whereas, their respective concentrations increased to 23.6, 42.0 and 10.0 microM with the addition of Pd ions. The observed phenomenon was further confirmed by the identification of HO-DMPO spin adducts using ESR spectroscopy. Taken together, our data suggest that the mechanism of Pd or Pt ion-mediated exacerbation of DNA damage by a Fenton system is due to the promotion of OH. production by these metal ions.
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Abstract
"This paper reviews the main characteristics of migration data for movements into and out of Thailand. It considers only international migration and it covers the following areas: (1) who collects and disseminates international migration data for Thailand; (2) what sorts of data are available; and (3) what are the major characteristics of these data. It is designed as a guide for persons using Thai migration data to help them interpret these data more clearly.... The paper concludes with some brief suggestions about how to improve migration data collection and dissemination in Thailand."
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131
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Comparison of the recombinant Escherichia coli-produced protease domain of tissue-type plasminogen activator with alteplase, reteplase and streptokinase in a canine model of coronary artery thrombolysis. Thromb Haemost 1996; 76:1096-101. [PMID: 8972037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Recent in vitro studies have shown that although recombinant Escherichia coli-produced protease domain of tissue-type plasminogen activator (t-PA) has no appreciable fibrin binding and less plasminforming activity compared to the wild-type, it is nevertheless an effective fibrinolytic agent in a dynamic in vitro plasma clot lysis system. The purpose of the present study was to evaluate the pharmacological profile of the protease in a canine model of coronary artery thrombosis. The effects of a single i.v. bolus injection of 1 mg/kg protease were compared with those of alteplase, reteplase and streptokinase at clinically relevant doses and dosing regimens in eight dogs per group. The protease rapidly restored coronary blood flow at 12 +/- 1 min in all treated dogs with a significantly higher maximal coronary blood flow than in the reference groups, but was associated with short cycles of reocclusion in 4/8 animals. Overall, the coronary blood flow quality of the protease was not significantly different from that of the reference thrombolytics. Although fibrinogen was nearly completely degraded during protease treatment, the bleeding time was not significantly more prolonged than in reference groups. In conclusion, the protease domain is a rapidly acting, effective, bolus-injectable thrombolytic agent associated with a systemic lytic state and does not appear to cause significantly more bleeding than the reference thrombolytic agents.
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Composite fermions with orbital magnetization. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:R11114-R11117. [PMID: 9984999 DOI: 10.1103/physrevb.54.r11114] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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133
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Bosonic description of spinning strings in 2+1 dimensions. PHYSICAL REVIEW. D, PARTICLES AND FIELDS 1996; 54:3981-3984. [PMID: 10021076 DOI: 10.1103/physrevd.54.3981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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134
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The intracellular reducing environment modulates cytoregulation and cytotoxicity by reactive oxygen species. Biochem Soc Trans 1996; 24:884-7. [PMID: 8878868 DOI: 10.1042/bst0240884] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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Effect of disulfide bonds on the structure, function, and stability of the trypsin/tPA inhibitor from Erythrina caffra: site-directed mutagenesis, expression, and physiochemical characterization. Nat Biotechnol 1996; 14:476-80. [PMID: 9630923 DOI: 10.1038/nbt0496-476] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Erythrina trypsin/tPA inhibitor (ETI) from the seeds of Erythrina caffra retains its native structure and inhibitory function after reducing its two disulfide bonds. In order to elucidate the specific role of these crosslinks, alanine residues were substituted for cysteines after cloning the gene in Escherichia coli. Expression of the recombinant inhibitor and the substitution mutants, C83A, CC39, 83AA, and CC132, 139AA, led to inclusion bodies. After solubilization in guanidinium-chloride (GdmCl)/dithiothreitol and oxidation in glutathione buffer, activity could be recovered at yields up to 80%. The mutant proteins exhibit full inhibitory function without detectable alterations of their native structure. However, their stability is reduced: at acid pH, where the oxidized natural inhibitor retains its native structure, the reduced wildtype protein and the mutants undergo at least partial denaturation, reflected by decreased pH ranges of stability: pH 5-7 for the reduced inhibitor, pH 2.5-8.5 for CC132, 139AA, and pH 3.5-8.5 for C83A and CC39, 83AA. Urea and GdmCl denaturation at pH 7 show hysteresis for both the oxidized inhibitor and the double mutant CC132, 139AA. In contrast, the reduced protein and the other mutants exhibit true equilibrium transitions at pH 7, with urea half-concentrations of 0.9 M and 1.9 M and GdmCl half-concentrations of 0.5 M and 1.0 M, respectively. The stability of Erythrina trypsin/tPA inhibitor follows the sequence: oxidized ETI > CC132, 139AA > CC39, 83AA and C83A > reduced ETI.
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The recombinant Escherichia coli-derived protease-domain of tissue-type plasminogen activator is a potent and fibrin specific fibrinolytic agent. ACTA ACUST UNITED AC 1996. [DOI: 10.1016/s0268-9499(96)80084-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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138
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Effective thrombolysis by a recombinant Escherichia coli-produced protease domain of tissue-type plasminogen activator in the rabbit model of jugular vein thrombosis. ACTA ACUST UNITED AC 1996. [DOI: 10.1016/s0268-9499(96)80083-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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139
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Abstract
The main purpose of this review article is to provide a better understanding of the role of oxidants as modulators/mediators of tyrosine phosphorylation-dependent signal transduction pathways. It is generally accepted that reversible phosphorylation of protein tyrosine residues by polypeptide growth factor receptor protein tyrosine kinases (e.g., epidermal growth factor receptor, platelet derived growth factor receptor, insulin receptor) is a signalling mechanism implicated in cell proliferation, adhesion, differentiation, transformation, and apoptosis. It is controlled by the opposing actions of protein tyrosine kinases and protein tyrosine phosphatases. Nevertheless, increasing amounts of experimental data indicate that intracellular redox state plays a major role in the mechanisms underlying the actions of growth factors. Furthermore, redox active species mediate signalling processes on their own. Thus, in this article we attempted to discuss these points, presenting our published as well as unpublished contribution to the field.
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140
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Singularities in the Fermi-liquid description of a partially filled Landau level and the energy gaps of fractional quantum Hall states. PHYSICAL REVIEW. B, CONDENSED MATTER 1995; 52:5890-5906. [PMID: 9981779 DOI: 10.1103/physrevb.52.5890] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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141
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Is allergy screening of blood donors necessary? A comparison between questionnaire answers and the presence of circulating IgE antibodies. Vox Sang 1995; 69:114-9. [PMID: 8585191 DOI: 10.1111/j.1423-0410.1995.tb01680.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We investigated 477 consecutive blood donors on order to find the predictive value of a questionnaire as a screening method for preventing passive transfer of IgE antibodies to common allergens that might cause transfusion reactions. Of the 477 donors, 119 (24.9%) claimed to be allergic and 358 (75.1%) recorded no allergic complaints. Serological examination with Phadiatop and a multi-allergen mix for food (fx5) detected IgE antibodies in only 54.5% of the allegedly allergic blood donors. Among the allegedly asymptomatic donors, 12.3% showed positive results in these tests. Subsequently, radioallergosorbent test analyses with common inhalant and food allergens were performed to specify the IgE responses obtained. Our results demonstrate a remarkable difference between the questionnaire answers and the serological measurements of IgE antibodies and raise the question of whether - and if so, what kind of - allergy screening is warranted among presumptive blood donors.
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143
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Infection control for our patients and ourselves. JEMS : A JOURNAL OF EMERGENCY MEDICAL SERVICES 1995; 20:92-3, 95. [PMID: 10143270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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144
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All patients are created equal. JEMS : A JOURNAL OF EMERGENCY MEDICAL SERVICES 1995; 20:162, 165. [PMID: 10154965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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145
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Abstract
A 33-year-old woman without history of previous atopic diseases or drug allergies developed a severe anaphylactic reaction with asthma, vomiting, itching, generalized urticaria, and angioedema during artificial insemination with her husband's sperm. The sperm-processing medium contained bovine serum albumin (BSA). Skin prick test and RAST demonstrated an IgE-mediated hypersensitivity to BSA as well as a polyvalent atopic sensitization to pollens, animal danders, cow's milk, beef, pork, and mutton. SDS-PAGE studies indicated serum albumin to be the appropriate allergen with a high degree of cross-reactivity between serum albumin from different animal species. Artificial insemination with fluid containing potential allergens can, therefore, represent an unnecessary risk for atopic females, even in the absence of prior clinical symptoms of allergic diseases. Preoperative testing with the medium is recommended.
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Nitric oxide stimulates tyrosine phosphorylation in murine fibroblasts in the absence and presence of epidermal growth factor. Biochem J 1995; 305 ( Pt 2):613-9. [PMID: 7530447 PMCID: PMC1136406 DOI: 10.1042/bj3050613] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
In the present study, utilizing anti-phosphotyrosine monoclonal antibodies, sodium nitroprusside (SNP) and S-nitroso-N-acetylpenicillamine (SNAP) as sources of NO and murine fibroblasts expressing the human epidermal growth factor (EGF) receptor (HER14 cells), we showed that tyrosine phosphorylation of a set of proteins (126, 56 and 43 kDa) was stimulated when cells were incubated with either SNP or SNAP and abolished by Methylene Blue and oxyhaemoglobin. Inhibition by Methylene Blue suggested an involvement of cyclic GMP in the process, which was evidenced by the effects of 8-bromo cyclic GMP. This analogue of cyclic GMP stimulated tyrosine phosphorylation of the same set of proteins phosphorylated after incubation with the NO source. Tyrosine phosphorylation of the same set of proteins was stimulated when cells were incubated simultaneously with SNP and EGF, showing that NO also potentiates EGF-evoked tyrosine kinase activity in HER14 cells. However, stimulation of the autophosphorylation of the EGF receptor, above the levels obtained for EGF alone, was not observed under those conditions. Additionally, we investigated the effects of NO on EGF-receptor tyrosine phosphatase activities in HER14 cells. Increasing concentrations of NO correlate with a gradual inhibition of these activities in HER14 cells, either in intact cells or in cell lysates. Taken together, these observations suggest that NO modulates tyrosine phosphorylation in HER14 cells.
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Identification and characterization of specific sequences encoding pathogenicity associated proteins in the genome of commensal Neisseria species. FEMS Microbiol Lett 1995; 125:255-63. [PMID: 7875573 DOI: 10.1111/j.1574-6968.1995.tb07366.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The distribution of distinct sequences in pathogenic and commensal Neisseria species was investigated systematically by dot blot analysis. Probes representing the genes of Rmp, pilin and IgA1 protease were found to hybridize exclusively to the chromosomal DNA of the pathogenic species, Neisseria gonorrhoeae and/or Neisseria meningitidis. In contrast, specific sequences for the genes of the porin protein Por and the opacity protein (Opa) were also detected in a panel of commensal Neisseria species such as N. lactamica, N. subflava, N. flava, N. mucosa and N. sicca. Using opa-specific oligonucleotides as probes in chromosomal blots, the genomes of the commensal Neisseria species show a totally reduced repertoire of cross-hybridizing loci compared to the complex opa gene family of N. gonorrhoeae. DNA sequence analysis of one opa-related gene derived from N. flava and N. sicca, respectively, revealed a large degree of homology with previously described gonococcal and meningococcal genes, e.g., a typical repetitive sequence in the leader peptide and the distribution of the hypervariable and conserved regions. This observation, together with the finding, that the gene is constitutively transcribed, leads to the assumption that some of the commensal Neisseria species may have the potential for the expression of a protein harboring similar functions as the Opa proteins in pathogenic Neisseriae.
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Disposables vs. reusables. Throw and go vs. use and reuse. JEMS : A JOURNAL OF EMERGENCY MEDICAL SERVICES 1994; 19:77-9, 81. [PMID: 10138499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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149
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Quantum Hall fluid of vortices in a two-dimensional array of Josephson junctions. PHYSICAL REVIEW. B, CONDENSED MATTER 1994; 50:10092-10106. [PMID: 9975093 DOI: 10.1103/physrevb.50.10092] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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150
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Abstract
OBJECTIVE To evaluate sexually abused children and their families at intake and 18 months later, in comparison with a control group. METHODS Eighty-four sexually abused children aged 5 to 15 years were assessed at intake, with 64 being able to be reassessed at 18 months, the assessment using measures of self-esteem relevant to their age; the Children's Depression Inventory, and the Achenbach Child Behavior Checklist. Parents were assessed with the McMaster Family Assessment Device and the General Health Questionnaire. Control children and families were similarly assessed. Additional measures at follow-up were a structured interview with the parents, the Indices of Coping Responses, and the Newcastle Child and Family Life Events Schedule. Therapists were contacted to obtain information on type and duration of therapy. RESULTS While the control children's self-esteem, depression, and behavior scores showed little change over time, the abused children's scores were more likely to move toward the normal range although 56% remained in the dysfunctional range for self-esteem, 48% for behavior, and 35% for depression. Improvement in child behavior was related to improvement in family function. While there was no direct relationship between child outcome and the relationship of the abuser to the child, family dysfunction, which was related to child outcome, did correlate with the closeness of the abuser to the child. Sixty-five percent of abused children had received therapy for an average of 9 months. No relationship was found between therapy and outcome. CONCLUSIONS The major variable relating to improvement in sexually abused children appears to be adequacy of family functioning. There is a need for increased emphasis on the evaluation of treatment.
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