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Abstract
Stringent quality control cannot be overemphasized in performing SPECT. SPECT artifacts related to camera uniformity, center of rotation, and the patient's motion are well recognized. In this communication, another rare cause of a SPECT artifact related to a triad system is reported. A triple-headed SPECT system was accidentally equipped with two ultrahigh-resolution collimators and a general all-purpose collimator during a brain SPECT study, causing a false cerebral blood flow defect.
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277
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Cho WH, Park CH, Lee SH, Park SB, Kim HC. Acute rejection after living donor renal transplantation. Transplant Proc 1994; 26:1995-6. [PMID: 8066647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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278
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Kim HC, Park SB, Lee SH, Cho WH, Park CH, Park KK. Analysis of 214 percutaneous allograft renal biopsies. Transplant Proc 1994; 26:2197-8. [PMID: 8066719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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279
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Park CH, Ryu DS, Kim KS, Cho WH, Park SB, Kim HC. Urologic morbidity of vesicoureteral reflux in the renal transplantation candidate. Transplant Proc 1994; 26:2189-90. [PMID: 8066716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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280
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Park CH, Ryu DS, Kim KS, Cho WH, Park SB, Kim HC. Vesicoureteric reflux following renal transplantation: significance and risks. Transplant Proc 1994; 26:2191-2. [PMID: 8066717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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281
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Park SB, Kim HC, Lee SH, Cho WH, Park CH. Evolution of serum ferritin levels in renal transplant recipients with severe iron overload. Transplant Proc 1994; 26:2054-5. [PMID: 8066668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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282
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Kim HC, Park SB, Lee SH, Cho WH, Park CH, Park KK. Analysis of 214 percutaneous renal allograft biopsies. Transplant Proc 1994; 26:1997-8. [PMID: 8066648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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283
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Kim HC, Park SB, Lee SH, Park KK, Park CH, Cho WH. Proteinuria in renal transplant recipients: incidence, cause, and prognostic importance. Transplant Proc 1994; 26:2134-5. [PMID: 8066696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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284
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Park CH, Nishimura K, Kitano M, Okamoto Y, Ban T. Right ventricular performance is impaired by full assist of left heart bypass. Analysis of right ventricular performance against change in afterload in heart failure models. ASAIO J 1994; 40:M303-8. [PMID: 8555529 DOI: 10.1097/00002480-199407000-00013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The purpose of this study was to assess right ventricular (RV) performance during left heart bypass (LHB) and to determine the optimum LHB driving conditions to preserve RV performance. LHB was established with a centrifugal pump in eight mongrel dogs weighing 11-19 kg. Failing heart models were induced by normothermic aortic clamping for 20 min. RV volume was measured by a conductance catheter, and RV performance was evaluated by two parameters. One was the slope of the RV end-systolic pressure-volume relationship (ESPVR) as a load independent index, and the other was the peak RV pressure (PRVP)-RV stroke volume (RVSV) relationship as a "force-velocity relationship." These parameters were measured during varying assist ratios of LHB at 0% to 100% of pulmonary artery flow, and varying afterload as induced by bilateral intrapulmonary balloon inflation. In failing hearts, RV ESPVR showed an inverse correlation, with the assist ratio of LHB significantly decreasing from 4.23 +/- 1.35 (mmHg/ml) to 3.52 +/- 1.30 (mmHg/ml; P < 0.05) after 100% LHB assist. The correlation between PRVP and RVSV also was inversely linear, the slope of this correlation becoming significantly steeper after 100% LHB assist compared to that without LHB (-0.131 +/- 0.042 vs. -0.051 +/- 0.038, P < 0.005). These two slopes intersected, and this intersection was considered the critical point of afterload above which RVSV was decreased by LHB compared to that without LHB. In addition, reducing the assist ratio made the slope of the PRVP-RVSV correlation significantly more gentle (70%: -0.072 +/- 0.037 vs. 100%: -0.131 +/- 0.042, P < 0.05), with the intersection of the two slopes shifting rightward (i.e., higher afterload). Consequently, the critical level of afterload at 70% LHB assist was significantly higher than that at 100% LHB assist (70%: 38.1 +/- 6.9 vs. 100%: 29.2 +/- 6.8, P < 0.05). Therefore, RV performance against afterload was improved by reducing the assist ratio of LHB. This study demonstrates that RV performance is impaired by full LHB assist if the RV afterload is above the critical level, and that reducing the assist ratio may improve RV performance against afterload.
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286
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Park CH, Chadi DJ. First-principles study of the atomic reconstructions of ZnSe(100) surfaces. PHYSICAL REVIEW. B, CONDENSED MATTER 1994; 49:16467-16473. [PMID: 10010798 DOI: 10.1103/physrevb.49.16467] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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287
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Kim SM, Park CH, Intenzo CM, McEwan JR. Findings of diffuse lymphadenitis secondary to rheumatoid arthritis and synovitis on Tc-99m labeled leukocyte scan. Clin Nucl Med 1994; 19:549-50. [PMID: 8062481 DOI: 10.1097/00003072-199406000-00021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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288
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Park CH, Sancar A. Formation of a ternary complex by human XPA, ERCC1, and ERCC4(XPF) excision repair proteins. Proc Natl Acad Sci U S A 1994; 91:5017-21. [PMID: 8197175 PMCID: PMC43921 DOI: 10.1073/pnas.91.11.5017] [Citation(s) in RCA: 138] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The xeroderma pigmentosum complementation group A (XP-A) protein, XPA, has recently been expressed in Escherichia coli in a soluble and fully functional form. An affinity column was prepared by linking the XPA protein to a solid support. When HeLa cell-free extract capable of excision repair was applied to the column, > 99.9% of the proteins were in the flow-through. However, the flow-through fraction lacked excision activity. The activity was restored by adding the high salt (1 M KCl) eluate of the column to the flow-through fraction. The XPA protein-bound fraction was tested for specific proteins by an in vitro complementation assay with a panel of cell-free extracts from DNA repair-deficient human and rodent cell lines. The XPA-bound fraction complemented cell-free extracts of excision repair cross-complementing 1 (ERCC-1), ERCC-4 (XP-F), and XP-A mutants. We conclude that the XPA damage recognition protein makes a ternary complex with the ERCC1/ERCC4(XPF) heterodimer with a potential nuclease function.
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289
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Park CH, Martinez B. Growth and production characteristics of permeabilized Coleus blumei cells in immobilized fed-batch culture. PLANT CELL REPORTS 1994; 13:459-463. [PMID: 24194026 DOI: 10.1007/bf00231967] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/1993] [Revised: 01/19/1994] [Indexed: 06/02/2023]
Abstract
Permeabilized Coleus blumei cells were cultivated in an immobilized state to study the effect of dimethyl sulfoxide (DMSO) concentrations and growth regulators on cell growth and rosmarinic acid (RA) production characteristics. Luffa (the fibrous skeleton of mature fruit of Luffa cylindrica) was a good support matrix for cell immobilization because of its high void volume. Maximum cell loading capacity was 1.33 g dry cell weight (DCW)/g dry Luffa. The experiments were done in shake flasks with no free medium. The medium was supplied in a fed-batch mode to avoid the flotation of Luffa pieces. The sucrose in the medium was completely hydrolyzed to glucose and fructose without any sugar accumulation in the medium. The cell viability was slightly higher in the cells on top of the Luffa than those in the middle. Cell growth rate and rosmarinic acid (RA) production were approximately half that obtained in cell suspension cultures. Cell yield (g DCW/g glucose) was similar to that of cell suspension cultures. The absence of growth regulators did not promote an increase of RA production but did decrease the cell mass. The second step preconditioning with 0.5% DMSO did not improve the cell's adaptability to higher DMSO concentrations and the cell mass did not increase with 2.5% DMSO.
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290
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Zhang JJ, Kim SM, Park CH, Intenzo CM. The "count loss" artifact in Tc-99m HMPAO leukocyte SPECT of the abdomen. Clin Nucl Med 1994; 19:430-4. [PMID: 8039318 DOI: 10.1097/00003072-199405000-00012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
During SPECT studies of the abdomen with Tc-99m labeled autologous leukocytes, the authors had observed false defects involving the vertebral bodies of the lower thoracic spine in two patients. To investigate this "count loss" artifact, a phantom simulating liver, spleen, and spine was constructed. Four clinical situations were simulated by positioning cylinders in the different locations: normal spine-spleen model, normal liver-spine-spleen model, spine-enlarged spleen model, and enlarged liver-spine-enlarged spleen model. SPECT studies were performed at different concentration ratios between the spleen and the spine on the disparate models with varying distance from the spleen to the spine. The results showed that the count loss artifact is not only related to the concentration ratio between the structures but also is related to the size, position, and distance between the structures. The correction steps for this artifact include: 1) identifying average count value of the spine and spleen from ECT sinogram count data, and 2) replacing the original high-count value in the spleen by the count value close to the average value at the region of the spine in the 120 raw projection data. Using these new modified ECT data, the reconstructed orthogonal images are almost free of the count loss artifact.
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291
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Abstract
Recently, ring A reduced metabolites of naturally occurring steroids have been shown to act as allosteric modulators of GABA-gated chloride ion conductance. Specifically, 5 alpha-pregnane-3 alpha,21-diol-20-one (allotetrahydrodeoxycorticosterone; 5 alpha-THDOC) was shown to be a positive allosteric effector. For example, 5 alpha-THDOC enhances the specific binding of [3H]flunitrazepam, a benzodiazepine receptor agonist, among other pharmacological actions. Swim stress has been shown to reduce the ability of flurazepam, a prototypic benzodiazepine agonist, to antagonize the electrical precipitation of tonic hindlimb extension in mice. This stress-induced reduction in flurazepam's antiseizure efficacy persists for up to 72 h and is associated with alterations in the specific binding of ligands to the GABAA receptor complex. In the current study, the potentiation of [3H]flunitrazepam binding by 5 alpha-THDOC was greater in cerebral cortical membranes prepared from stressed mice compared with unstressed controls. Moreover, nanomolar concentrations of 5 alpha-THDOC that were ineffective in potentiating the specific binding of [35S]TBPS in cerebral cortical membranes prepared from unstressed control mice were capable of potentiating this binding in membranes prepared from stressed animals. Specifically, 50 nM 5 alpha-THDOC caused a 23% increase in the specific binding of [35S]TBPS in membranes from stressed mice, whereas it was without any significant effect in unstressed controls. This apparent ability of 5 alpha-THDOC to distinguish between the binding of [35S]TBPS to crude membranes prepared from stressed and unstressed control mice was eliminated in the presence of a 5 microM concentration of GABA.(ABSTRACT TRUNCATED AT 250 WORDS)
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292
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Kim GR, Lee YT, Park CH. A new natural reservoir of hantavirus: isolation of hantaviruses from lung tissues of bats. Arch Virol 1994; 134:85-95. [PMID: 8279962 DOI: 10.1007/bf01379109] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Two species of bats were confirmed as new natural reservoirs of hantavirus. Antibodies to Hantaan virus were detected in 3.40% (23 of 677) of bats captured from 1989 to 1992 in Korea by the IFA technique. Areal distribution of immunofluorescent antibody were different, and seropositive rates were much high in sera of bats captured in summer (3.82%) and winter (5.82%). Viral antigens were observed in the lungs (3 of 16) and kidney (1 of 7). Two hantaviruses were isolated from lung tissues of E. serotinus and R. ferrum-equinum through a cell culture system, designated CUMC-92B8 and -92B48, respectively. Using Rous associated virus-2 reverse transcriptase-directed PCR and 2 oligonucleotide primer pairs, genomic sequences of the isolates were amplified. Amplified products of the isolates and reactivities to monoclonal antibodies very closely resembled those of Hantaan virus. These data suggest that the serotype of the isolates is closely related to Hantaan virus, and bats serve as reservoirs of hantavirus.
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293
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Ellingboe JW, Antane M, Nguyen TT, Collini MD, Antane S, Bender R, Hartupee D, White V, McCallum J, Park CH. Pyrido[2,3-d]pyrimidine angiotensin II antagonists. J Med Chem 1994; 37:542-50. [PMID: 8120871 DOI: 10.1021/jm00030a013] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A series of pyrido[2,3-d]pyrimidine angiotensin II (A II) antagonists was synthesized and tested for antagonism of A II. Compounds with a biphenylyltetrazole pharmacophore and small alkyl groups at the 2- and 4-positions of the pyridopyrimidine ring were found to be the most potent in an AT1 receptor binding assay and in blocking the A II pressor response in anesthetized, ganglion-blocked A II-infused rats. 5,8-Dihydro-2,4-dimethyl-8-[(2'-(1H-tetrazol-5-yl) [1,1'-biphenyl]-4-yl)methyl]pyrido[2,3-d]pyrimidin-7(6H)-one (4a) was one of the more potent compounds in the binding assay and was the most efficacious compound in the A II-infused rat model. Further study of 4a in Goldblatt (2K-1C) rats showed the compound to have oral bioavailability and to be an efficacious and potent compound in a high renin form of hypertension.
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294
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Park CH, Cheong BH, Lee KH, Chang KJ. Structural and electronic properties of cubic, 2H, 4H, and 6H SiC. PHYSICAL REVIEW. B, CONDENSED MATTER 1994; 49:4485-4493. [PMID: 10011368 DOI: 10.1103/physrevb.49.4485] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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295
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Park CH, Kim SM, McEwan JR, Intenzo C, Cohn H. Small parathyroid adenoma associated with hyperactive bone demonstrated by Tc-99m MIBI scintiscan. Clin Nucl Med 1994; 19:160. [PMID: 8187406 DOI: 10.1097/00003072-199402000-00021] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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296
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Park CH, Kim SM, Zhang J, McEwan JR, Intenzo C. Tc-99m MIBI brain SPECT of an acoustic schwannoma. Clin Nucl Med 1994; 19:152-4. [PMID: 8187404 DOI: 10.1097/00003072-199402000-00018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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297
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Park CH, Kim SM, Zhang JJ, Intenzo CM, McEwan JR. Tc-99m MIBI brain SPECT in the diagnosis of recurrent glioma. Clin Nucl Med 1994; 19:57-8. [PMID: 8137586 DOI: 10.1097/00003072-199401000-00015] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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298
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Yoo HS, Park CH, Lee JT, Kim KW, Yoon CS, Suh JH, Park CY, Kim BS, Choi HJ, Lee KS. Small hepatocellular carcinoma: high dose internal radiation therapy with superselective intra-arterial injection of I-131-labeled Lipiodol. Cancer Chemother Pharmacol 1994; 33 Suppl:S128-33. [PMID: 8137473 DOI: 10.1007/bf00686684] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The aim of the present study was to deliver a high internal radiation dose to small hepatocellular carcinoma (HCC) lesions in an attempt to treat this disease. A total of 18 patients with HCC lesions measuring less than 4.5 cm in diameter (25 lesions) were treated with superselective intra-arterial injection of I-131-labeled Lipiodol (370-1,100 MBq in 3-5 ml) using a 5-F or coaxial catheter. All the lesions were nodular, multinodular, or hypervascular on pretreatment angiography. In all, 15 lesions that received over 180 Gy of cumulative radiation decreased in size in proportion to the Lipiodol retention on CT, and no pericapsular recurrence was found on angiography after 14-54 months of follow-up. In five patients who subsequently underwent surgery, 65% to 100% tumor necrosis was detected. No abnormal change in liver function tests or untoward clinical symptom of the lung, thyroid, or bone marrow was detected in patients who survived for more than 3 years after the treatment. Superselective high-dose internal radiation therapy of small HCC offers hope of treatment and long-term local control without complications.
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299
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Park CH, Kimler BF. Tumor cell-selective flow cytometric analysis for DNA content and cytokeratin expression of clinical tumor specimens by "cross-gating". Anticancer Res 1994; 14:29-36. [PMID: 7513144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
A major problem with flow cytometric analysis of clinical solid tumor specimens is that of non-malignant cell contamination which contributes to inaccurate results. Monoclonal antibody to cytokeratin, a marker for epithelial tumor (carcinoma) cells, was successfully used in conjunction with a DNA-specific dye to dually stain specimens so as to obtain DNA profiles exclusively for marker-positive tumor cells. This gating procedure was used also for analysis of the cell marker distribution for those cells having a DNA content consistent with aneuploidy. After successful verification in model systems, clinical carcinoma specimens were studied. The aneuploid population increased from a mean of 61% without gating to a mean of 81% with gating for cytokeratin. The cytokeratin-positive cell fraction increased from a mean of 55% without gating to a mean of 96% with gating for aneuploid DNA content. This gating procedure makes it possible to associate cell markers confidently with tumor cell populations, thus providing objective verification of the tissue of origin for these tumors. It can be performed simultaneously with standard gating for DNA analysis; and both procedures used together, cross-gating, are invaluable for more precise analysis of human tumor DNA and cell markers.
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300
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Park CH, Hixon DL, Morrison WL, Cook CB. Rapid diagnosis of enterohemorrhagic Escherichia coli O157:H7 directly from fecal specimens using immunofluorescence stain. Am J Clin Pathol 1994; 101:91-4. [PMID: 8166805 DOI: 10.1093/ajcp/101.1.91] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Serotype O157:H7 is most frequently encountered among verotoxin-producing Escherichia coli. Most laboratories use MacConkey-sorbitol agar as a screening medium. Presumptive identification of sorbitol-negative colonies is then accomplished by latex agglutination or biochemical tests with serologic confirmation, which requires 18-36 hours for completion. This study attempted to detect E coli O157:H7 directly from stool specimens by direct immunofluorescence (DIF) antibody staining to provide quicker turnaround (< 2 hours). A total of 336 abnormal fecal samples (bloody, watery, semi-liquid, or mucoid) were examined by this method. Results were compared with those of culture. Direct immunofluorescence antibody staining of the direct fecal smear detected all isolates of E coli O157 that were recovered by culture, including nonmotile strains, strains possessing the H7 flagellar antigen, and one strain with a flagellar antigen other than H7. Optimum results were achieved when specimens were pretreated with 5% bleach and centrifugation. No false-negative results were obtained with bleach-pretreated stool samples.
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