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Palomaki GE, Ashwood ER, Weck KE. A flawed challenge but valid recommendation: a response to Takoudes and Hamar. Ultrasound Obstet Gynecol 2015; 45:117. [PMID: 25557844 DOI: 10.1002/uog.14739] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Affiliation(s)
- G E Palomaki
- Department of Pathology and Laboratory Medicine, Women & Infants Hospital/Alpert Medical School at Brown University, Providence, RI, USA
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2
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Willman JH, Hill HR, Martins TB, Jaskowski TD, Ashwood ER, Litwin CM. Multiplex analysis of heterophil antibodies in patients with indeterminate HIV immunoassay results. Am J Clin Pathol 2001; 115:764-9. [PMID: 11345842 DOI: 10.1309/3f13-739a-na7f-nv3x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
We hypothesized that heterophil antibodies reactive with animal proteins used in blot preparation caused nonspecific staining (NSS) on HIV Western blot (WB) studies, causing indeterminate results. We analyzed samples showing NSS on HIV WB using a multiplexed immunoassay to simultaneously measure IgG antibodies to animal IgG (bovine, goat, sheep, mouse) and bovine serum albumin. Heterophil antibodies reactive with IgG from several animal species were detected in 23 (49%) of 47 samples showing NSS on HIV WB; 15 positive samples demonstrated antibodies to all 5 antigens. Similar IgG heterophil antibodies were detected in only 2 (8%) of 24 control samples. Of the HIV WB samples with a positive HIV-1 enzyme-linked immunosorbent assay (ELISA) result at the time of WB testing (11/47), heterophil antibodies were found in 8 (73%) of 11. Preabsorption with bovine, goat, and sheep IgG removed heterophil antibodies detected by the multiplexed assay and, in some cases, eliminated reactivity in ELISA and WB testing. Heterophil antibodies are associated with indeterminate HIV immunoassay results and are an important cause of false-positive HIV ELISA results. Multiplexed immunoassays provide a powerful tool for screening patients for heterophil antibodies and resolving possible false-positive results.
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Affiliation(s)
- J H Willman
- Associated Regional and University Pathologists (ARUP), Institute for Clinical and Experimental Pathology, University of Utah School of Medicine, Salt Lake City, USA
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3
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Abstract
Lamellar bodies, concentrically layered "packages" of phospholipid that represent the storage form of surfactant, can be counted in the platelet channel of most electronic cell counters. The lamellar body count has been used for more than a decade and performs as well as traditional phospholipid analysis as an assay for evaluating fetal lung maturity. It is preferable to phospholipid analysis because it is rapid, objective, and inexpensive and can be performed in any hospital laboratory. The current methodologies for specimen preparation vary widely among laboratories, most notably with respect to centrifugation, resulting in differences in maturity cutoffs used. Our goal was to establish a consensus regarding a standardized methodology for the lamellar body count. Institutions that previously had published their results with lamellar body counts were invited to contribute. The consensus of the four participating institutions includes the following: centrifugation is not a necessary step and should be abandoned, maturity is suggested by a count of 50,000/microL or greater, and immaturity is suggested by a count of 15,000/microL or lower. As the lamellar body count gains wider acceptance as a primary assay for assessing fetal lung maturity, the test must be performed uniformly and accurately, given the implications of acting on a falsely negative test resulting from improper methodology.
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Affiliation(s)
- M G Neerhof
- Department of Obstetrics and Gynecology, Northwestern University Medical School, Evanston Northwestern Healthcare, Evanston, Illinois, USA.
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Neerhof MG, Haney EI, Silver RK, Ashwood ER, Lee IS, Piazze JJ. Lamellar body counts compared with traditional phospholipid analysis as an assay for evaluating fetal lung maturity. Obstet Gynecol 2001; 97:305-9. [PMID: 11165600 DOI: 10.1016/s0029-7844(00)01133-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
OBJECTIVE To compare lamellar body counts with the lecithin/sphingomyelin ratio and phosphatidylglycerol analysis in terms of assessment of risk of respiratory distress syndrome (RDS). METHODS Lamellar body counts, lecithin-sphingomyelin ratios (L/Ss), and phosphatidylglycerol levels were assessed in 1611 amniotic fluid samples obtained at four clinical sites from pregnant women whose fetuses were at risk for RDS. Cases in which delivery occurred within 72 hours of sample collection (n = 833) were analyzed. Specific cutoffs for predicting the likelihood of RDS for both the lamellar body count and the L/S had been derived previously at each of the clinical sites based on receiver operating characteristic curves using unrelated samples, whereas phosphatidylglycerol was reported as either mature (present) or immature (absent). Standard clinical and radiographic criteria were used to diagnose RDS, and the diagnosis was confirmed by review of newborn records. RESULTS One hundred (12.0%) of the 833 infants delivered within 72 hours of sample collection developed RDS. The negative predictive value of the lamellar body count (97.7%) was similar to that of the L/S (96.8%) and slightly better than that of phosphatidylglycerol analysis (94.7%) (P =.048). The lamellar body count performed as well as phospholipid analysis irrespective of gestational age or patient population. CONCLUSION The lamellar body count compares favorably with traditional phospholipid analysis as an assay for assessment of fetal lung maturity. Lamellar body counts are preferable because they are faster, more objective, less labor intensive, less technique dependent, and less expensive and because they can be performed with equipment available in every hospital laboratory.
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Affiliation(s)
- M G Neerhof
- Department of Obstetrics and Gynecology, Northwestern University Medical School, Evanston Northwestern Healthcare, Evanston, Illinois, USA.
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5
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Dufour DR, Ashwood ER, Nolte FS, Seeff LB. More on viral hepatitis. Am J Clin Pathol 2000; 114:660-4. [PMID: 11026110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023] Open
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Abstract
We evaluated the performance characteristics of the COBAS AMPLICOR Hepatitis C Virus (HCV) MONITOR Test, version 2.0. Dilution studies using patient specimens demonstrated a lower limit of detection of 1,000 copies per milliliter. The assay was linear from 1,000 to 1 million HCV RNA copies per milliliter. Within-run precision and between-run precision were acceptable (approximately 0.100 and 0.14 SD for log10 [copies per milliliter]). A comparison of this version of the test (y), with the manual AMPLICOR HCV MONITOR Test, version 1.0 (x), yielded the following Deming regression equation: y = 1.004(+/- 0.04)x + 0.654(+/- 0.22); Sy/x¿D = 0.336; n = 92; r2 = 0.846; r = 0.920. Further comparison of the COBAS version 2.0 assay (x) with the QUANTIPLEX HCV bDNA Test (y) yielded the following Deming regression equation: y = 0.943 (+/- 0.130)x + 0.473 (+/- 0.717); Sy/x¿D = 0.194; n = 26; r2 = 0.600; r = 0.774. Version 2.0 detected the spectrum of HCV genotypes better than version 1.0.
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Affiliation(s)
- M Erali
- ARUP Institute for Clinical and Experimental Pathology, Salt Lake City, UT 84108, USA
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7
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Abstract
Maternal serum alpha-fetoprotein (MS-alphaFP) testing is widely used to screen for fetal defects. MS-alphaFP concentrations are affected by a number of variables such as gestational age, maternal weight, number of fetuses, race, and insulin-dependent diabetes. Undefined geographic factors may also influence MS-alphaFP. We have examined the effect of altitude in a sample of 1063 MS-alphaFP results selected to span a range of altitudes. The study sample was subjected to linear regression with and without a term for altitude, and multiple-of-the-median (MoM) values were calculated before and after adjusting for altitude. The median MS-alphaFP was found to decrease an average of 1 ng/mL for every 1100 ft increase in altitude, a change approximately equivalent to that seen with an increase in maternal weight of 6 lb. Adjusting for altitude resulted in the reclassification of 36 of 1063 patient results (3.4%), although the clinical utility of this adjustment remains unexamined.
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Affiliation(s)
- K L Nuttall
- Department of Pathology, University of Utah, Salt Lake City, UT, USA.
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8
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Ashwood ER. Acute coronary syndromes: from bench to bedside--the Twenty-first annual Arnold O. Beckman Conference in Clinical Chemistry. Clin Chem 1998; 44:1795-7. [PMID: 9702988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- E R Ashwood
- Department of Pathology, University of Utah School of Medicine, Salt Lake City 84108, USA.
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Komaromy-Hiller G, Nuttall KL, Ashwood ER. Effect of storage on serum vitamin B12 and folate stability. Ann Clin Lab Sci 1997; 27:249-53. [PMID: 9210969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
To facilitate transport from remote locations, the stability of vitamin B12 and folate was investigated in serum specimens. Serum vitamin B12 proved to be highly unstable, emphasizing that specimens should be frozen if not analyzed immediately. Light protection is necessary if the sample cannot be analyzed within 4 hours. In contrast, folate is a more robust analyte. In refrigerated serum specimens, folate was stable up to 7 days of storage. In situations where specimen stability is important, vitamin B12 status is better assessed with serum or urine methylmalonic acid measurements. Although folate status can be assessed in a similar fashion with homocysteine, specimen stability indicates that direct measurement of folate is a better strategy.
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Affiliation(s)
- G Komaromy-Hiller
- Department of Pathology, University of Utah School of Medicine, Salt Lake City 84132, USA
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Johnson NH, Ash KO, Nuttall KL, Ashwood ER. The adequacy of capillary specimens for determining whole blood lead. Ann Clin Lab Sci 1997; 27:179-84. [PMID: 9142369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
In response to demands for reliable alternatives to collection of venous specimens for determination of whole blood lead levels in children, the Centers for Disease Control has called for increased research into capillary methodologies. In this study, a three tiered approach was developed to assess the adequacy of capillary specimens for determining whole blood lead. Patient blood lead results from capillary and venous specimens were compared for obvious differences. Next, follow-up specimens for patients with elevated lead levels were compared with the initial results. In addition, experiments were conducted to determine whether or not handwashing eliminates gross contamination. Although the differences are not clinically important, the mean, 3.83 micrograms/dL for 5,100 venous specimens, was significantly lower (p < 0.005) then the mean of 4.6 micrograms/dL for 1,100 capillary specimens. Gross contamination was rare. Lead levels in follow-up specimens on patients whose initial screens were elevated were generally low. Handwashing greatly reduced the amount of external lead contamination. It is concluded that capillary specimens are an acceptable alternative to venous specimens for whole blood screening programs provided the patient and collector meticulously follow the prescribed collection protocol. Nevertheless, all elevated whole blood lead screening results, venous or capillary, should be confirmed with a venous collection before follow-up action is taken.
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Affiliation(s)
- N H Johnson
- 81 MIDOS/SHOKI, Clinical Research Laboratory, Keesler AFB, MS 39534, USA
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11
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Ashwood ER. Standards of laboratory practice: evaluation of fetal lung maturity. National Academy of Clinical Biochemistry. Clin Chem 1997; 43:211-4. [PMID: 8990255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
In this standard of laboratory practice I recommend guidelines for fetal lung maturity (FLM) testing. If possible, obtain a 10-mL uncontaminated sample by amniocentesis. Keep the amniotic fluid at 4 degrees C and mix well before testing. If centrifugation is required, strictly adhere to the protocol. Most laboratories should offer a rapid test, such as fluorescence polarization, phosphatidylglycerol, or foam stability index, daily on both a routine and emergency basis. Requests for lecithin/sphingomyelin ratio may be referred to a reference laboratory. Communicate immediately the results of any FLM test to the ordering location. The report should contain the result, sample contamination, and reference information. Separate reference intervals for diabetic patients are not recommended.
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Affiliation(s)
- E R Ashwood
- Department of Pathology, University of Utah School of Medicine, Salt Lake City 84108, USA.
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Nuttall KL, Pingree SS, Ashwood ER. Reference intervals for 24-hour and random urine porphyrins. Ann Clin Lab Sci 1996; 26:313-22. [PMID: 8800431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Urine porphyrin analysis is an important part in evaluation of photosensitivity. Since porphyrin excretion is variable throughout the day, analysis is traditionally based on 24-hour collections. To facilitate the use of random specimens, as well as poorly collected 24-hour specimens, reference limits based on the porphyrin to creatinine ratio have been developed. Based on 1,171 adult specimens, it is estimated that the 95 percent reference limit (90 percent confidence interval) is < or = 3.9 (3.5-5.7) mumol/mol of creatinine for uroporphyrin and < or = 22 (19-34) mumol/mol for coproporphyrin. These values apply to both 24-hour and random specimens, although random specimens show a higher degree of variability. Modest differences exist between males and females, but they are not significant given the degree of uncertainty in the confidence intervals. In terms of more traditional 24-hour units, reference limits correspond to < or = 37 (32-63) nmol/day for uroporphyrin and < or = 221 (195-320) nmol/day for coproporphyrin.
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Affiliation(s)
- K L Nuttall
- Department of Pathology University of Utah School of Medicine Salt Lake City 84132, USA
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Abstract
Abstract
We describe an enzymatic method for measuring phosphatidylglycerol (PG) at concentrations as low as 0.2 mumol/L in amniotic fluid. Amniotic fluid (1.5 mL) is centrifuged at 10,000g for 20 min to obtain a lamellar body pellet, which is reconstituted with 0.5 mL of buffer. The PG is measured by a two-step enzymatic scheme. Recovery studies demonstrated that the pellet contains > 97% of the PG present in amniotic fluid. Between-run CVs were 28%, 5.7%, and 2.6% for amniotic fluid controls with means of 0.32, 3.9, and 10.7 mumol/L, respectively (n = 20). The enzymatic procedure was not significantly affected by blood, meconium, bilirubin, or other phospholipids. Lecithin/sphingomyelin ratio (n = 101) and fluorescence polarization (n = 127) compared with log(PG) showed correlation coefficients of 0.832 and -0.866, respectively. This test's ability to detect low concentrations of PG in amniotic fluid may make it a better predictor of fetal lung immaturity than previous methods.
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Affiliation(s)
- G W Jones
- Department of Pathology, University of Utah, School of Medicine, Salt Lake City 84132
| | - E R Ashwood
- Department of Pathology, University of Utah, School of Medicine, Salt Lake City 84132
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14
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Jones GW, Ashwood ER. Enzymatic measurement of phosphatidylglycerol in amniotic fluid. Clin Chem 1994; 40:518-25. [PMID: 8149604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
We describe an enzymatic method for measuring phosphatidylglycerol (PG) at concentrations as low as 0.2 mumol/L in amniotic fluid. Amniotic fluid (1.5 mL) is centrifuged at 10,000g for 20 min to obtain a lamellar body pellet, which is reconstituted with 0.5 mL of buffer. The PG is measured by a two-step enzymatic scheme. Recovery studies demonstrated that the pellet contains > 97% of the PG present in amniotic fluid. Between-run CVs were 28%, 5.7%, and 2.6% for amniotic fluid controls with means of 0.32, 3.9, and 10.7 mumol/L, respectively (n = 20). The enzymatic procedure was not significantly affected by blood, meconium, bilirubin, or other phospholipids. Lecithin/sphingomyelin ratio (n = 101) and fluorescence polarization (n = 127) compared with log(PG) showed correlation coefficients of 0.832 and -0.866, respectively. This test's ability to detect low concentrations of PG in amniotic fluid may make it a better predictor of fetal lung immaturity than previous methods.
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Affiliation(s)
- G W Jones
- Department of Pathology, University of Utah, School of Medicine, Salt Lake City 84132
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15
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Balis UJ, Aller RD, Ashwood ER. Informatics training in U.S. pathology residency programs. Results of a survey. Am J Clin Pathol 1993; 100:S44-7. [PMID: 8311028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Affiliation(s)
- U J Balis
- Department of Pathology, University of Utah School of Medicine, Salt Lake City
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16
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Barman BN, Ashwood ER, Giddings JC. Separation and size distribution of red blood cells of diverse size, shape, and origin by flow/hyperlayer field-flow fractionation. Anal Biochem 1993; 212:35-42. [PMID: 8368513 DOI: 10.1006/abio.1993.1287] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Red blood cells (RBCs) from human, equine, canine, feline, and bovine whole blood samples have been separated and characterized by high-speed flow/hyperlayer field-flow fractionation (Fl/HyFFF). The elution-based separation of RBCs by this method is based mainly on the size and shape of the cell particles. The typical separation time for RBCs is less than 3 min. Size distributions can be derived from the fractograms of cell samples using a calibration plot based on retention data for uniform polystyrene beads. The method is shown to be effective both to separate and to characterize cell populations, including those with cells of abnormal shape and size. In order to investigate differences in cell morphology, shape and size changes induced by 500,000 Da Dextran were monitored. The changes in the Fl/HyFFF elution profiles indicate that the RBCs decrease in size but become partially aggregated in the presence of the dextran. These changes were found to depend on polymer concentration and specific blood samples. Some of the results from Fl/HyFFF were compared with those from the Coulter counter and from microscopy.
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Affiliation(s)
- B N Barman
- FFFractionation, Inc., Salt Lake City, Utah 84158
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17
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Ashwood ER, Palmer SE, Taylor JS, Pingree SS. Lamellar body counts for rapid fetal lung maturity testing. Obstet Gynecol 1993; 81:619-24. [PMID: 8459979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
OBJECTIVE To evaluate amniotic fluid lamellar body counting as a fetal lung maturity test. Lamellar body particles can be rapidly counted using the platelet channel of most blood cell analyzers. METHODS We conducted a 3-year prospective clinical outcome study. During the interval under study, outcomes of 247 neonates were used to evaluate the test; 28 neonates developed respiratory distress syndrome (RDS). Lecithin-sphingomyelin ratio (L/S) was available for 187 cases. RESULTS All cases of RDS had lamellar body counts of 55,000/microL or less and L/S of 2.2 or less; 59% of cases with no RDS had counts greater than 55,000/microL and 70% of normal cases had L/S higher than 2.2. CONCLUSION Use of lamellar body counts is justified as a rapid screening test to predict fetal lung maturity. Immature results should be followed by a more specific test such as L/S.
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Affiliation(s)
- E R Ashwood
- Department of Pathology, University of Utah School of Medicine, Salt Lake City
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18
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Ruch AT, Lenke RR, Ashwood ER. Assessment of fetal lung maturity by fluorescence polarization in high-risk pregnancies. J Reprod Med 1993; 38:133-6. [PMID: 8445605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Although the validity of amniotic fluid fluorescence polarization (FPOL) has been documented in normal pregnancies, data are lacking on the predictive value of this method in high-risk pregnancies where biochemical maturation of the fetal lung may be altered. In this study, amniotic fluid was obtained from 86 women with pregnancies complicated by insulin-dependent diabetes (42), twin gestation (22), Rh sensitization (13) and known fetal anomalies (9). In all groups, when FPOL was > .280 (immature), phosphatidylglycerol (PG) was always absent and lecithin and sphingomyelin ratio (L/S) was < 2.5:1. When FPOL values were < .260 (mature), PG was always present and L/S was > 2.5 in 45/50 samples. When FPOL values ranged between .260-.280 (intermediate), L/S and PG values varied and were inconsistent. We conclude that FPOL assessment of fetal lung maturity in pregnancies complicated by diabetes, Rh sensitization, twin gestation and fetal anomalies is as accurate a procedure as is fetal lung maturity testing by L/S and PG. In addition, the testing procedure is quicker, more reproducible and, possibly, more reliable.
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Affiliation(s)
- A T Ruch
- Center for Women and Children, Toledo Hospital/Medical College of Ohio
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19
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Affiliation(s)
- R S Petersen
- Department of Anesthesiology, University of Utah Health Sciences Center, Salt Lake City 84132
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20
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Ashwood ER, Palmer SE, Lenke RR. Rapid fetal lung maturity testing: commercial versus NBD-phosphatidylcholine assay. Obstet Gynecol 1992; 80:1048-53. [PMID: 1448250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
We compared the TDx Fetal Lung Maturity test and the fluorescence polarization method using 1-palmitoyl-2(6-[(7-nitro-2,1,3-benzoxadiazol-4- yl)amino]caproyl)phosphatidylcholine (NBD-phosphatidylcholine). Using 76 paired human amniotic fluid samples, the fluorescence polarization values of the two methods were found to have a strong nonlinear correlation (r2 = 0.946). Both assays can be completed in less than 1 hour, have excellent precision (between-day variation less than 2%), and indicate the amount of surfactant phospholipid relative to albumin. The FLM assay is calibrated with surfactant/albumin standards; therefore, the reported results (in mg/g) correlate inversely with polarization of NBD-phosphatidylcholine. Strong correlations were seen for both assays with the lecithin-sphingomyelin ratio and phosphatidylglycerol. The correlations indicate that the recommended reference range for FLM will have more false predictions of immaturity than the NBD-phosphatidylcholine assay.
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Affiliation(s)
- E R Ashwood
- Department of Pathology, University of Utah School of Medicine, Salt Lake City
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21
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Kershisnik MM, Kalamegham R, Ash KO, Nixon DE, Ashwood ER. Using 16O35Cl to correct for chloride interference improves accuracy of urine arsenic determinations by inductively coupled plasma mass spectrometry. Clin Chem 1992; 38:2197-202. [PMID: 1424111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
We have observed inaccurate urine arsenic values with the method of isobaric fractionation, which was designed to correct for the 40Ar35Cl interference with 75As quantitation by inductively coupled plasma mass spectrometry. Isobaric fractionation, which is based on ion intensities at m/z 77 and 82, consistently underestimates the 40Ar35Cl interference and overestimates urine arsenic. We present an improved method for identifying the argon-chloride interference. We observed that signal intensities for the species 16O35Cl and 40Ar35Cl are proportional (I75 = 0.0295 x I51 - 14.7, r2 = 0.998; where Ix is the normalized ion intensity at m/z X) in water and urine, over a broad range of chloride concentrations (0-800 mmol/L). The proportionality constant is remarkably stable within a run (mean and SD, 0.0295 +/- 0.0023, based on 10 replicates of five chloride calibrators, 0, 100, 200, 400, and 800 mmol/L). Increased sensitivity (50-fold) for detecting the 40Ar35Cl interference provides improved accuracy for urine arsenic quantitation as demonstrated by a split-sample comparison with graphite-furnace atomic absorption spectrophotometry.
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Affiliation(s)
- M M Kershisnik
- Department of Pathology, University of Utah Medical Center, Salt Lake City 84132
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22
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Kershisnik MM, Kalamegham R, Ash KO, Nixon DE, Ashwood ER. Using 16O35CL to Correct for Chloride Interference Improves Accuracy of Urine Arsenic Determinations by Inductively Coupled Plasma Mass Spectrometry. Clin Chem 1992. [DOI: 10.1093/clinchem/38.11.2197] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
We have observed inaccurate urine arsenic values with the method of isobaric fractionation, which was designed to correct for the 40Ar35Cl interference with 75As quantitation by inductively coupled plasma mass spectrometry. Isobaric fractionation, which is based on ion intensities at m/z 77 and 82, consistently underestimates the 40Ar35Cl interference and overestimates urine arsenic. We present an improved method for identifying the argon-chloride interference. We observed that signal intensities for the species 16O35Cl and 40Ar35Cl are proportional (I75 = 0.0295 x I51 - 14.7, r2 = 0.998; where Ix is the normalized ion intensity at m/z X) in water and urine, over a broad range of chloride concentrations (0-800 mmol/L). The proportionality constant is remarkably stable within a run (mean and SD, 0.0295 +/- 0.0023, based on 10 replicates of five chloride calibrators, 0, 100, 200, 400, and 800 mmol/L). Increased sensitivity (50-fold) for detecting the 40Ar35Cl interference provides improved accuracy for urine arsenic quantitation as demonstrated by a split-sample comparison with graphite-furnace atomic absorption spectrophotometry.
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Affiliation(s)
- M M Kershisnik
- Department of Pathology, University of Utah Medical Center, Salt Lake City 84132
| | - R Kalamegham
- Department of Pathology, University of Utah Medical Center, Salt Lake City 84132
| | - K O Ash
- Department of Pathology, University of Utah Medical Center, Salt Lake City 84132
| | - D E Nixon
- Department of Pathology, University of Utah Medical Center, Salt Lake City 84132
| | - E R Ashwood
- Department of Pathology, University of Utah Medical Center, Salt Lake City 84132
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Ashwood ER. Evaluating health and maturation of the unborn: the role of the clinical laboratory. Clin Chem 1992; 38:1523-9. [PMID: 1386562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
I review the utility of several common prenatal laboratory tests. Infant mortality is higher in the United States than in many other industrialized nations; better access to early prenatal care may help reduce this mortality rate. Several common laboratory tests can significantly contribute to prenatal care. Early measurement of maternal serum human chorionic gonadotropin can permit estimation of the date of conception. Use of maternal serum alpha-fetoprotein in the second trimester provides the clinician with risk estimates for neural tube defects and Down syndrome. Adding human chorionic gonadotropin and possibly unconjugated estriol to this screen can increase the number of Down syndrome cases identified without increasing the proportion of abnormal results. Amniotic fluid fetal lung maturity tests can assist with the management of delivery.
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Affiliation(s)
- E R Ashwood
- Department of Pathology, University of Utah School of Medicine, Salt Lake City 84108
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24
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Ashwood ER, Labart PL. Laboratory information system test environment: validate upgrades, prevent disasters, and assist training. Clin Lab Manage Rev 1992; 6:66-8, 70-1. [PMID: 10116936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
A laboratory information system (LIS) test environment allows the laboratory to run and test programs without affecting the current production environment. This is essential for successfully introducing system enhancements and upgrades because it allows the LIS manager to uncover software errors before introducing them into the actual LIS system. A test environment is also a useful tool for training employees. In addition, a test environment enables laboratories to validate software before use in the live environment, which will probably be required by the Food and Drug Administration and the Health Care Financing Administration inspectors now that LISs are considered medical devices. This article examines the benefits, uses, and limitations of an LIS test environment; discusses the computer resources required; and explores the process of installing and validating a software release.
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Affiliation(s)
- E R Ashwood
- Associated University and Regional Pathologists, Salt Lake City, UT
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25
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Weilert M, Ashwood ER, Skinner M. The ins and outs of laboratory information systems. Combining the hospital and reference laboratory. Clin Lab Med 1991; 11:153-69. [PMID: 2040139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Regulatory and reimbursement pressure on laboratory and hospital organizations have led to diversified or hybrid combinations of hospital inpatient, outpatient, and reference laboratory operations. Laboratory information system (LIS) requirements to integrate these operations become more complex than for either operation alone, because inpatient and reference operations have different and sometime conflicting priorities. Careful attention to LIS requirements is necessary to implement hybrid laboratory operations systems successfully.
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Affiliation(s)
- M Weilert
- Department of Pathology, Community Hospitals of Central California, Fresno
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26
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Osorio e Castro VR, Ashwood ER, Wood SG, Vernon LP. Hemolysis of erythrocytes and fluorescence polarization changes elicited by peptide toxins, aliphatic alcohols, related glycols and benzylidene derivatives. Biochim Biophys Acta 1990; 1029:252-8. [PMID: 2245210 DOI: 10.1016/0005-2736(90)90161-g] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Hemolysis rates of human erythrocytes induced by C2 and C8-C14 straight chain 1-alkanols, 1,2-alkanediols and the corresponding benzylidene derivatives (benzaldehyde acetals) have been studied and compared with hemolysis rates obtained by three peptide toxins. The peak of activity occurs at C12 for the alkanols and glycols and at C10 for the benzylidene derivatives. The most active compound is 1-dodecanol, followed by 1,2-dodecanediol and the C10 benzylidene acetal, which show 50% hemolysis at 15, 99 and 151 microM, respectively, at 37 degrees C. A few lysolecithins and longer chain cis-unsaturated alcohols were studied for comparison purposes, and were found to be more active than 1-dodecanol. The most active were the 16:0 lysolecithin and cis-9-tetradecene-1-ol, which gave 50% hemolysis at concentrations of 2.8 and 5.6 microM respectively. The hemolytic activities of 1-dodecanol, 1,2-dodecanediol and the C10 benzylidene acetal were compared to activities of Pyrularia thionin and melittin with cow, horse, sheep, pig and human erythrocytes. Whereas the peptide toxins showed clear specificity for human erythrocytes, no selectivity was shown by any of the other compounds tested. Addition of the thionin or Naja naja kaouthia cardiotoxin to erythrocyte ghosts caused a slight but reproducible increase in the order of the phospholipid bilayer, as measured with the fluorescent probe NBD-PC. Cardiotoxin gave a greater response than did the P thionin, and extensively iodinated P thionin gave a smaller change than did P thionin. Similar results were obtained with melittin, but this peptide gave a markedly greater response than all other peptides. Addition of dodecanol or the C10 benzylidene acetal caused a marked increase in membrane fluidity. All of these data indicate that the organic compounds interact directly with and are incorporated nonspecifically into the membrane lipid bilayer, but the peptide toxins interact specifically with some component on the surface of the membrane, either a protein or specific phospholipid domain, followed by insertion into the membrane and decreasing phospholipid movement.
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27
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Carlson KK, Snyder ML, LeClair HW, Underhill SL, Ashwood ER, Detter JC. Obtaining reliable plasma sodium and glucose determinations from pulmonary artery catheters. Heart Lung 1990; 19:613-9. [PMID: 2228651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
In critically ill patients, blood specimens are frequently withdrawn from intravascular catheters without consideration of possible infusate contamination, of test accuracy, or of undue blood loss. The reliability of sodium (Na+) and glucose determinations withdrawn from the venous infusion port of a pulmonary artery catheter was studied in 30 patients after cardiac surgery. Catheter patency was maintained by a saline and heparin infusate. Venipuncture samples for Na+ and glucose served as controls. A sample containing the dwell volume of the catheter and the stopcock (1 ml) was withdrawn and discarded, followed by fifteen 1 ml samples being taken for analysis. It was concluded that Na+ values are stable after discard of the catheter dwell volume and an additional milliliter of blood. Minimal clinical differences were found in the glucose values after discard of the catheter dwell volume and two additional milliliters of blood.
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28
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Steen PD, Ashwood ER, Huang K, Daynes RA, Chung HT, Samlowski WE. Mechanisms of pertussis toxin inhibition of lymphocyte-HEV interactions. I. Analysis of lymphocyte homing receptor-mediated binding mechanisms. Cell Immunol 1990; 131:67-85. [PMID: 2225081 DOI: 10.1016/0008-8749(90)90235-j] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The molecular mechanisms by which pertussis toxin (PTX) inhibits lymphocyte homing to peripheral lymph nodes (PLN) remain poorly understood. PTX-treated lymphocytes express homing receptors, yet cannot extravasate into PLN in vivo. Methylation of PTX, a procedure known to inactivate the B-oligomer of the toxin, restored high endothelial venule (HEV) binding capacity. In vitro studies established that toxin exposure inhibited the accessory role of LFA-1 in HEV binding. In contrast, PTX-exposed lymphocytes exhibited normal MEL-14-mediated HEV binding. Analysis of membrane fluidity revealed a 20% decrease in fluorescence polarization in PTX-exposed lymphocytes. On the basis of the current experiments, we propose a "zipper" model of lymphocyte-HEV interaction, in which lateral mobility of adhesion receptors in the cell membrane toward a site of endothelial contact is necessary to maintain adhesion against the shear force due to blood flow. PTX inhibits these processes by decreasing membrane fluidity, and by altering accessory adhesion molecule function.
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Affiliation(s)
- P D Steen
- University of Utah/VAMC Cancer Immunotherapy Program, Salt Lake City
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29
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Ruch AM, Lenke R, Ashwood ER. Assessment of fetal lung maturity in high risk pregnancies by fluorescence polarization. Neonatal Intensive Care 1990; 3:26-7, 36. [PMID: 10148933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Affiliation(s)
- A M Ruch
- Department of Obstetrics and Gynecology, Medical College of Ohio, Toledo
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30
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Salyer JL, Bohnsack JF, Knape WA, Shigeoka AO, Ashwood ER, Hill HR. Mechanisms of tumor necrosis factor-alpha alteration of PMN adhesion and migration. Am J Pathol 1990; 136:831-41. [PMID: 2183625 PMCID: PMC1877646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
We have investigated the effects of recombinant human tumor necrosis factor-alpha (rhTNF alpha) on polymorphonuclear leukocytes (PMNs), concentrating on the mechanisms involved in the alterations of PMN-directed migration and adherence by this cytokine. RhTNF alpha profoundly suppressed PMN chemotaxis toward FMLP by 80%. At similar concentrations, it enhanced adhesion to gelatin-coated plastic dishes by more than tenfold and increased the expression of the CD11b antigen to 182% of the control. The monoclonal antibody 60.1, which is directed against the alpha chain of the CD11b/CD18 complex, completely blocked rhTNF alpha, induced inhibition of the chemotactic response to FMLP, and rhTNF alpha induced hyperadherence, suggesting that these effects were related to rhTNF alpha's effects on CD11b antigen expression. The fluid state of the PMN membrane was also decreased by rhTNF alpha. N-butanol, a known membrane fluidizer, partially inhibited the effect of rhTNF alpha on membrane fluidity and chemotaxis and completely reversed its effects on adherence and the expression of the CD11b antigen. Pentoxifylline, an agent that has previously been studied for its ability to prevent some effects of rhTNF alpha on PMNs, completely prevented the effect of rhTNF alpha on chemotaxis, the expression of the CD11b antigen, and membrane fluidity. Pentoxifylline partially prevented changes in adherence caused by this cytokine. Increased CD11b antigen expression caused by rhTNF alpha may result in enhanced PMN adhesion and suppression of migration. These events may, in turn, lead to the accumulation of PMNs on the vascular endothelium, resulting in the extensive vascular and tissue damage that is seen in gram-negative sepsis.
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Affiliation(s)
- J L Salyer
- Department of Pathology, University of Utah, Salt Lake City 84132
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31
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Ashwood ER, Oldroyd RG, Palmer SE. Measuring the number of lamellar body particles in amniotic fluid. Obstet Gynecol 1990; 75:289-92. [PMID: 2300359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We describe a method for determining the number and size distribution of lamellar bodies and compare the results prospectively with other tests for fetal lung maturity: lecithin-sphingomyelin ratio (L/S), phosphatidylglycerol, and fluorescence polarization. The technique uses an electronic particle counter calibrated for a size range of 1.7-7.3 fL. The number of lamellar bodies in amniotic fluid samples varied from 3800-166,000 particles per microliter and correlated strongly with L/S ratio (r = 0.75; N = 144) and fluorescence polarization (r = -0.78; N = 165). Amniotic fluid samples stored for up to 10 days at 4C had stable lamellar body counts (within +/- 11%). Longer storage tended to decrease the counts. Addition of more than 1% (v/v) whole blood significantly decreased the lamellar body counts. This technique shows promise for the rapid assessment of fetal lung maturity.
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Affiliation(s)
- E R Ashwood
- Department of Pathology, University of Utah School of Medicine, Salt Lake City
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32
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Weiss RL, Ashwood ER, Kjeldsberg CR. Multilobated B-cell lymphoma. A clinicopathologic study of 24 cases. Arch Pathol Lab Med 1990; 114:28-33. [PMID: 2403778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The clinical, histologic, and immunologic features of 24 cases of multilobated B-cell lymphoma are presented and compared with those of previously reported cases. Cases were included in this study when more than 50% of the tumor cells had nuclear multilobation. There were 13 males and 11 females with an age range of 13 to 79 years. A slight predominance of node-based presentations was observed. Seventeen patients (71%) presented with advanced (stage III or IV) disease. Complete remissions were achieved in 13 (59%) of 22 patients, and 14 (58%) of the 24 patients were still alive after a follow-up period ranging from 10 to 124 months. The 1-year survival was 65% (SE = 10%). Relapses occurred in 4 (31%) of 13 patients with complete responses. These observations, together with those previously reported, support the conclusion that the multilobated B-cell variant of non-Hodgkin's lymphoma behaves in a fashion similar to that of the intermediate-grade, diffuse, large-cell non-Hodgkin's lymphomas.
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Affiliation(s)
- R L Weiss
- Department of Pathology, University of Utah School of Medicine, Salt Lake City 84132
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33
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Ulirsch RC, Ashwood ER, Noce P. Security in the clinical laboratory. Guidelines for managing the information resource. Arch Pathol Lab Med 1990; 114:89-93. [PMID: 2294872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The principal product produced by the clinical laboratory is information. This is true whether or not an automated system is used to organize and retrieve this information. It follows that great care must be exercised in ensuring that the stored data are accurate in the sense that they truly and always represent those data that were meant to be recorded. Various forces may act to compromise this information including (1) accidents, such as fire, floods, or earthquakes; (2) human error; and (3) deliberate acts, such as sabotage or theft of information. An organized plan for systematically managing the "information resource" has become critical. To safeguard against the potential catastrophic loss of information, a formal information resource management policy must be adopted within the clinical laboratory and directed by a specific individual, under the guidance of the director of pathology.
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Affiliation(s)
- R C Ulirsch
- Department of Pathology, Loyola University Medical Center, Maywood, IL 60153
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Newton JA, Ashwood ER, Yang KD, Augustine NH, Hill HR. Effect of pentoxifylline on developmental changes in neutrophil cell surface mobility and membrane fluidity. J Cell Physiol 1989; 140:427-31. [PMID: 2550471 DOI: 10.1002/jcp.1041400304] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Polymorphonuclear leukocytes (PMNs) from human neonates respond less efficiently to chemotactic factor stimulation than do PMNs from adults. The biologic mechanisms underlying this developmental process are poorly understood. In previous studies, we have found that pentoxifylline, an agent report to enhance membrane deformability, increased the chemotactic response of neonatal PMNs. In the present studies, we have examined the effect of pentoxifylline on cell surface mobility and membrane fluidity by assessing fluorescent concanavalin A (Con A) capping and fluorescent polarization (FP). Baseline Con A capping was lower in the PMNs of neonates when compared to PMNs from adult controls. Colchicine, which increases capping by disrupting microtubules, exaggerated the differences between the adult and neonatal PMNs. Following exposure of neonatal PMNs to pentoxifylline, colchicine enhanced Con A capping to levels equivalent to those of colchicine-treated PMNs from adults. Employing a fluorescence polarization (FP) assay, we found the fluid state of the membrane of PMNs from neonates was significantly less than that of adult controls. Pentoxifylline alone significantly increased the fluidity of the cell membranes of neonatal PMNs while decreasing elevated basal levels of F-actin in the cell. These data suggest an intrinsic cytoskeletal difference in the PMNs of neonates that may be responsive to pharmacologic manipulation.
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Affiliation(s)
- J A Newton
- Department of Pediatrics, University of Utah School of Medicine, Salt Lake City 84132
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35
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Lenke RR, Guerrieri J, Nemes JM, Kurczynski TW, French B, Gray M, Schut H, Ashwood ER. Elevated maternal serum alpha-fetoprotein values. How low is high? J Reprod Med 1989; 34:511-6. [PMID: 2478705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Most maternal serum alpha-fetoprotein (MSAFP) screening programs are set up with the goal of prenatal detection of fetal neural tube defects. It is also commonly accepted that MSAFP testing yields many false-positive results. Screening programs commonly utilize schemata that identify abnormal levels of MSAFP as greater than 2.5 multiples of the median (MOM) and also recommend two abnormal values before initiating ultrasound evaluation. Our pilot program evaluating obstetric outcomes found that 21 of the 29 women with elevated MSAFP values (greater than 2.0 MOM) eventually developed significant pregnancy management changes or complications of pregnancy. Thus, we believe that the use of MSAFP screening solely for the purpose of detecting fetal neural tube defects is inconsequential relative to its usefulness in detecting other pregnancy abnormalities. We also believe that ultrasound evaluation should be accomplished after the first abnormal value and that the cutoff of 2.5 MOM should be lowered to at least 2.0.
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Affiliation(s)
- R R Lenke
- Department of Obstetrics and Gynecology, Medical College of Ohio, Toledo
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36
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Terreros DA, Knight JA, Ashwood ER. Nickel inhibition of the osmotic-sensitive ionic cellular channels. Ann Clin Lab Sci 1988; 18:444-50. [PMID: 2467601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The effects of nickel on cell volume regulation were studied in isolated proximal renal tubules from Carassius auratus (goldfish). Variations in cell volume were measured as changes in the external tubular diameters as a function of time of exposure to NiCl2 (Ni(II] in both isotonic and hypotonic solutions. Renal tubules were first incubated in isotonic fish Ringer's solution (290 mOsm) with and without 0.05, 0.10, 0.50, and 1.00 mmol/L Ni(II) for three minutes. After this period, the bath solution was rapidly changed to hypotonic NaCl-poor Ringer's solution (110 mOsm). Renal cells exposed to Ni(II) (0.05 to 1.00 mmol/per L) did not undergo cell swelling in isotonic solutions. However, in a dose related manner, Ni(II) inhibited the volume regulatory process of cells exposed to hypotonic solutions. The effect of Ni(II) on cell volume regulation was specific to the osmoregulatory phase; that is, while there was no inhibition of the hypotonically-induced cell swelling (osmometric phase), there was a significant dose-dependent inhibition of the cellular volume regulatory decrease that follows (osmoregulatory phase). It is postulated by us that nickel inhibition of the osmoregulatory process is secondary to an inhibition of the osmotic sensitive ionic channels.
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Affiliation(s)
- D A Terreros
- Department of Pathology, University of Utah School of Medicine, Salt Lake City 84148
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37
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Ashwood ER, Chamberlain BV. Binding of fluorescent phosphatidylcholine in amniotic fluid. Obstet Gynecol 1988; 71:370-4. [PMID: 3347421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Fetal lung maturity can be predicted by the technique of fluorescence polarization using fluorescent phosphatidylcholine instead of diphenylhexatriene. To further elucidate the mechanism of this assay, we used high-speed centrifugation to isolate amniotic fluid lamellar bodies. Each of 75 amniotic fluid samples was separated into two fractions: a lamellar body pellet and a lamellar body-free supernatant fluid. Amniotic fluid and these fractions were assessed in a fluorescence polarization assay using a fluorescent phosphatidylcholine. Regardless of the maturity of the fetal lung, the lamellar body fractions had low polarization values (0.127-0.216), whereas the lamellar body-free fractions had high polarization values (0.266-0.344). Compared with the polarization of amniotic fluid, the fluorescence intensity of the lamellar body fractions had a strong inverse correlation (r = -0.871). The polarization of lamellar body pellets was not linearly related to the polarization of amniotic fluids. These findings do not support the theory that this fluorescence polarization assay measures the microviscosity of surfactant lipids. Instead, we propose that this assay indicates the quantity of surfactant relative to the quantity of nonsurfactant receptors of fluorescent phosphatidylcholine in amniotic fluid.
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Affiliation(s)
- E R Ashwood
- Department of Pathology, University of Utah School of Medicine, Salt Lake City
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38
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Talt JF, Foerder CA, Ashwood ER, Benedetti TJ. Prospective clinical evaluation of an improved fluorescence polarization assay for predicting fetal lung maturity. Clin Chem 1987; 33:554-8. [PMID: 3829389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
We performed a prospective clinical evaluation of our newly developed fluorescence polarization procedure to predict fetal lung maturity (Clin Chem 1986;32:248-54). Net fluorescence polarization was measured at 34 degrees C after a 6.5-min incubation of amniotic fluid with fluorophore. For the 26 cases of neonatal respiratory distress syndrome encountered in 196 deliveries, the net polarization exceeded 0.287 for 22 (85%) of these, and exceeded 0.260 for all 26. The specificity of the polarization assay equaled or exceeded the specificity of the lecithin/sphingomyelin ratio for all sensitivities greater than 70%. Neither assay was a good predictor of the clinical severity of respiratory distress. For a separate group of 21 amniotic fluid specimens clinically contaminated with blood or meconium, the discriminatory power of the polarization assay was decreased, but six of seven respiratory-distress cases still had polarization values greater than 0.260. We conclude that this fluorescence polarization assay is a better overall predictor of fetal lung maturity than is the lecithin/sphingomyelin ratio, and that polarization values less than 0.260 are associated with little risk of respiratory distress.
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39
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Talt JF, Foerder CA, Ashwood ER, Benedetti TJ. Prospective clinical evaluation of an improved fluorescence polarization assay for predicting fetal lung maturity. Clin Chem 1987. [DOI: 10.1093/clinchem/33.4.554] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Abstract
We performed a prospective clinical evaluation of our newly developed fluorescence polarization procedure to predict fetal lung maturity (Clin Chem 1986;32:248-54). Net fluorescence polarization was measured at 34 degrees C after a 6.5-min incubation of amniotic fluid with fluorophore. For the 26 cases of neonatal respiratory distress syndrome encountered in 196 deliveries, the net polarization exceeded 0.287 for 22 (85%) of these, and exceeded 0.260 for all 26. The specificity of the polarization assay equaled or exceeded the specificity of the lecithin/sphingomyelin ratio for all sensitivities greater than 70%. Neither assay was a good predictor of the clinical severity of respiratory distress. For a separate group of 21 amniotic fluid specimens clinically contaminated with blood or meconium, the discriminatory power of the polarization assay was decreased, but six of seven respiratory-distress cases still had polarization values greater than 0.260. We conclude that this fluorescence polarization assay is a better overall predictor of fetal lung maturity than is the lecithin/sphingomyelin ratio, and that polarization values less than 0.260 are associated with little risk of respiratory distress.
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40
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Ashwood ER, Cheng E, Luthy DA. Maternal serum alpha-fetoprotein and fetal trisomy-21 in women 35 years and older: implications for alpha-fetoprotein screening programs. Am J Med Genet 1987; 26:531-9. [PMID: 2436476 DOI: 10.1002/ajmg.1320260304] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A retrospective study of 3,411 women who underwent midtrimester amniocentesis for fetal chromosome analysis between June 1979 and August 1984 was performed to evaluate an association between low maternal serum alpha-fetoprotein (AFP) concentrations and Down syndrome (DS) pregnancies. A total of 71 pregnancies was found with abnormal fetal chromosomes; of these, 26 cases were trisomy-21 and 10 cases were trisomy-18. The maternal serum AFP in women with DS fetuses was relatively lower than levels in women with fetuses that had normal chromosomes. In addition, the AFP concentrations in amniotic fluid were decreased in cases involving DS fetuses. We have estimated the risks for DS pregnancy at all maternal ages and most serum AFP concentrations. Using these calculations, genetic counselors will be able to provide more accurate risk estimates for trisomy-21 following maternal serum AFP testing.
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41
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Tait JF, Franklin RW, Simpson JB, Ashwood ER. Improved fluorescence polarization assay for use in evaluating fetal lung maturity. I. Development of the assay procedure. Clin Chem 1986; 32:248-54. [PMID: 3753665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
We describe a fluorescence polarization assay for use in predicting fetal lung maturity, which is suitable for the TDx Analyzer (an automated fluorescence polarimeter). The assay requires 0.5 mL of amniotic fluid and approximately 30 min, and involves the fluorophore 1-palmitoyl-2(6-[(7-nitro-2, 1, 3-benzoxadiazol-4-yl)amino]caproyl) phosphatidylcholine. Reproducible polarization measurements depend on proper regulation of incubation time and temperature, but variations in the concentrations of fluorescent probe and amniotic fluid have little effect on measured polarization and therefore little effect on assay precision. Working solutions of the fluorescent probe are stable for at least nine months when stored at -20 degrees C and pH 5. Interferences include erythrocytes, serum, bilirubin, meconium, and lidocaine.
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42
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Ashwood ER, Tait JF, Foerder CA, Franklin RW, Benedetti TJ. Improved fluorescence polarization assay for use in evaluating fetal lung maturity. III. Retrospective clinical evaluation and comparison with the lecithin/sphingomyelin ratio. Clin Chem 1986. [DOI: 10.1093/clinchem/32.2.260] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
We clinically evaluated, retrospectively, our improved fluorescence polarization assay for fetal lung maturity. The procedure requires 0.5 mL of amniotic fluid and a standard clinical laboratory fluorescence polarimeter (TDx Analyzer, Abbott Laboratories). We measured the L/S ratios for 93 freshly collected amniotic fluids, uncontaminated with blood or meconium, collected within three days of delivery. The fluids were stored frozen for eight to 32 months, then thawed and assayed for net fluorescence polarization. Fourteen of the infants developed respiratory distress syndrome; five, transient tachypnea of the newborn; and 74, no respiratory distress. The polarization assay and lecithin/sphingomyelin ratio had equivalent receiver operating characteristic curves, indicating no difference in their clinical performance. Although a prospective study with fresh amniotic fluid specimens will be necessary to establish a definitive reference range, the present study shows that this assay can be used to rapidly predict fetal lung maturity.
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Foerder CA, Tait JF, Franklin RW, Ashwood ER. Improved fluorescence polarization assay for use in evaluating fetal lung maturity. II. Analytical evaluation and comparison with the lecithin/sphingomyelin ratio. Clin Chem 1986. [DOI: 10.1093/clinchem/32.2.255] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Abstract
We assessed the analytical performance of an improved fluorescence polarization assay for use in evaluating fetal lung maturity and compared results with the lecithin/sphingomyelin ratio. During a three-month period 150 patients' samples were assayed by clinical laboratory personnel with both techniques. Values for the lecithin/sphingomyelin ratio correlate closely with net fluorescence polarization values (r = -0.85), less closely with net fluorescence intensity (r = 0.65). Background fluorescence intensity and polarization varied widely, indicating a need to correct measurements for endogenous fluorescence. Net fluorescence polarization values have a CV of 0.32% within-run, 1.07% between-day. A comparison of two amniotic fluid centrifugation procedures showed no significant difference in such values. For both methods, however, such values are slightly but significantly higher than those obtained for amniotic fluids without prior centrifugation. Short-term storage (less than 30 days) of uncentrifuged amniotic fluid samples at -20 degrees C does not significantly affect results.
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Tait JF, Franklin RW, Simpson JB, Ashwood ER. Improved fluorescence polarization assay for use in evaluating fetal lung maturity. I. Development of the assay procedure. Clin Chem 1986. [DOI: 10.1093/clinchem/32.2.248] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
We describe a fluorescence polarization assay for use in predicting fetal lung maturity, which is suitable for the TDx Analyzer (an automated fluorescence polarimeter). The assay requires 0.5 mL of amniotic fluid and approximately 30 min, and involves the fluorophore 1-palmitoyl-2(6-[(7-nitro-2, 1, 3-benzoxadiazol-4-yl)amino]caproyl) phosphatidylcholine. Reproducible polarization measurements depend on proper regulation of incubation time and temperature, but variations in the concentrations of fluorescent probe and amniotic fluid have little effect on measured polarization and therefore little effect on assay precision. Working solutions of the fluorescent probe are stable for at least nine months when stored at -20 degrees C and pH 5. Interferences include erythrocytes, serum, bilirubin, meconium, and lidocaine.
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Ashwood ER, Tait JF, Foerder CA, Franklin RW, Benedetti TJ. Improved fluorescence polarization assay for use in evaluating fetal lung maturity. III. Retrospective clinical evaluation and comparison with the lecithin/sphingomyelin ratio. Clin Chem 1986; 32:260-4. [PMID: 3943183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
We clinically evaluated, retrospectively, our improved fluorescence polarization assay for fetal lung maturity. The procedure requires 0.5 mL of amniotic fluid and a standard clinical laboratory fluorescence polarimeter (TDx Analyzer, Abbott Laboratories). We measured the L/S ratios for 93 freshly collected amniotic fluids, uncontaminated with blood or meconium, collected within three days of delivery. The fluids were stored frozen for eight to 32 months, then thawed and assayed for net fluorescence polarization. Fourteen of the infants developed respiratory distress syndrome; five, transient tachypnea of the newborn; and 74, no respiratory distress. The polarization assay and lecithin/sphingomyelin ratio had equivalent receiver operating characteristic curves, indicating no difference in their clinical performance. Although a prospective study with fresh amniotic fluid specimens will be necessary to establish a definitive reference range, the present study shows that this assay can be used to rapidly predict fetal lung maturity.
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Foerder CA, Tait JF, Franklin RW, Ashwood ER. Improved fluorescence polarization assay for use in evaluating fetal lung maturity. II. Analytical evaluation and comparison with the lecithin/sphingomyelin ratio. Clin Chem 1986; 32:255-9. [PMID: 3753666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
We assessed the analytical performance of an improved fluorescence polarization assay for use in evaluating fetal lung maturity and compared results with the lecithin/sphingomyelin ratio. During a three-month period 150 patients' samples were assayed by clinical laboratory personnel with both techniques. Values for the lecithin/sphingomyelin ratio correlate closely with net fluorescence polarization values (r = -0.85), less closely with net fluorescence intensity (r = 0.65). Background fluorescence intensity and polarization varied widely, indicating a need to correct measurements for endogenous fluorescence. Net fluorescence polarization values have a CV of 0.32% within-run, 1.07% between-day. A comparison of two amniotic fluid centrifugation procedures showed no significant difference in such values. For both methods, however, such values are slightly but significantly higher than those obtained for amniotic fluids without prior centrifugation. Short-term storage (less than 30 days) of uncentrifuged amniotic fluid samples at -20 degrees C does not significantly affect results.
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Lenke RR, Ashwood ER, Cyr DR, Gravett M, Smith JR, Stenchever MA. Genetic amniocentesis: significance of intraamniotic bleeding and placental location. Obstet Gynecol 1985; 65:798-801. [PMID: 2582322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Simultaneous ultrasound was used to determine if there was a correlation between visualized intraamniotic bleeding, placental location, and fetal-maternal hemorrhage. It was hoped to then determine which Rh-negative patients should receive Rh immunoglobulin. Visualized intraamniotic bleeding showed no correlation to fetal-maternal hemorrhage. Intraamniotic bleeding was commonly associated with needle insertion through an anterior placenta, but also occurred regardless of placental location and in the absence of placental needle traversal. No correlation was found between placental location and fetal-maternal hemorrhage as evidenced by evaluation of maternal serum alpha-fetoprotein. The Kleihauer test was not as sensitive as alpha-fetoprotein.
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Ashwood ER, Kost G, Kenny M. Temperature correction of blood-gas and pH measurements. Clin Chem 1983; 29:1877-85. [PMID: 6354511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
We critically review formulas for temperature correction of pH, pCO2, and pO2 measurements in whole blood and the clinical usefulness of these formulas. We discuss both the theoretical derivation and experimental verification of temperature-induced changes. We recommend when to use and when not to use these formulas, based upon the clinical interpretation of these assays.
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Abstract
Abstract
We critically review formulas for temperature correction of pH, pCO2, and pO2 measurements in whole blood and the clinical usefulness of these formulas. We discuss both the theoretical derivation and experimental verification of temperature-induced changes. We recommend when to use and when not to use these formulas, based upon the clinical interpretation of these assays.
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