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Hofmann UK, Keller RL, von Bernstorff M, Walter C, Mittag F. Predictability of the effects of epidural injection in lumbar spinal stenosis by assessment of lumbar MRI scans. J Back Musculoskelet Rehabil 2020; 33:613-621. [PMID: 31743983 DOI: 10.3233/bmr-181249] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND Numerous classification systems have been proposed to interpret lumbar MRI scans. The clinical impact of the measured parameters remains unclear. To evaluate the clinical significance of imaging results in patients with multisegmental degenerative pathologies, treating specialists can perform image-guided local injections to target defined areas such as the epidural space. OBJECTIVE The aim of this retrospective study was to evaluate the correlation between lumbar spinal stenosis measurements obtained by MRI and improvement obtained through local epidural injection. METHODS In this retrospective study various measurement and classification systems for lumbar spinal stenosis were applied to MRI scans of 100 patients with this pathological condition. The reported effect of epidural bupivacaine/triamcinolone injections at the site was recorded in these patients and a comparative analysis performed. RESULTS MRI features assessed in this study did not show any relevant correlation with reported pain relief after epidural injection in patients with chronic lumbar stenosis, with the exception of posterior disc height with a weak Kendall's tau of -0.187 (p= 0.009). CONCLUSIONS Although MRI is crucial for evaluating lumbar spinal stenosis, it cannot replace but is rather complementary to a good patient history and clinical examination or the results of local diagnostic injections.
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Affiliation(s)
- Ulf Krister Hofmann
- Department of Orthopaedic Surgery, University Hospital of Tübingen, D-72076 Tübingen, Germany
| | - Ramona Luise Keller
- Department of Orthopaedic Surgery, University Hospital of Tübingen, D-72076 Tübingen, Germany.,Faculty of Medicine, Julius-Maximilians University of Würzburg, D-97080 Würzburg, Germany
| | - Maximilian von Bernstorff
- Department of Orthopaedic Surgery, University Hospital of Tübingen, D-72076 Tübingen, Germany.,Faculty of Medicine, Eberhard-Karls University of Tübingen, D-72076 Tübingen, Germany
| | - Christian Walter
- Department of Orthopaedic Surgery, University Hospital of Tübingen, D-72076 Tübingen, Germany
| | - Falk Mittag
- Department of Orthopaedic Surgery, University Hospital of Tübingen, D-72076 Tübingen, Germany
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Hofmann UK, Keller RL, Gesicki M, Walter C, Mittag F. Interobserver Reliability When Classifying MR Imaging of the Lumbar Spine: Written Instructions Alone Do Not Suffice. Magn Reson Med Sci 2019; 19:207-215. [PMID: 31548477 PMCID: PMC7553807 DOI: 10.2463/mrms.mp.2019-0079] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
PURPOSE Numerous classification systems have been proposed to analyze lumbar spine MRI scans. When evaluating these systems, most studies draw their conclusions from measurements of experienced clinicians. The aim of this study was to evaluate the impact of specific measurement training on interobserver reliability in MRI classification of the lumbar spine. METHODS Various measurement and classification systems were assessed for their interobserver reliability in 30 MRIs from patients with chronic lumbar back and sciatic pain. Two observers were experienced spine surgeons. The third observer was an inexperienced medical student who, prior to the study measurements, in addition to being given the detailed written instructions also given to the surgeons, obtained a list of 20 reference measurements in MRI scans from other patients to practice with. RESULTS Excellent agreement was observed between the medical student and the spine surgeon who had also created the reference measurements. Between the two spine surgeons, agreement was markedly lower in all systems investigated (e.g., antero-posterior spinal canal diameter intraclass correlation coefficient [ICC] [3.1] = 0.979 vs. ICC [3.1] = 0.857). CONCLUSION These data warrant the creation of publicly available standardised measurement examples of accepted classification systems to increase reliability of the interpretation of MR images.
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Affiliation(s)
| | | | - Marco Gesicki
- Department of Orthopaedic Surgery, University Hospital of Tübingen.,Praxis Dres. Falck and Gesicki
| | - Christian Walter
- Department of Orthopaedic Surgery, University Hospital of Tübingen
| | - Falk Mittag
- Department of Orthopaedic Surgery, University Hospital of Tübingen
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Hofmann UK, Keller RL, Walter C, Mittag F. Predictability of the effects of facet joint infiltration in the degenerate lumbar spine when assessing MRI scans. J Orthop Surg Res 2017; 12:180. [PMID: 29162138 PMCID: PMC5699022 DOI: 10.1186/s13018-017-0685-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2017] [Accepted: 11/12/2017] [Indexed: 12/13/2022] Open
Abstract
Background Imaging results are frequently considered as hallmarks of disease by spine surgeons to plan their future treatment strategy. Numerous classification systems have been proposed to quantify or grade lumbar magnetic resonance imaging (MRI) scans and thus objectify imaging findings. The clinical impact of the measured parameters remains, however, unclear. To evaluate the pathological significance of imaging findings in patients with multisegmental degenerative findings, clinicians can perform image-guided local infiltrations to target defined areas such as the facet joints. The aim of the present retrospective study was to evaluate the correlation of MRI facet joint degeneration and spinal stenosis measurements with improvement obtained by image-guided intraarticular facet joint infiltration. Methods Fifty MRI scans of patients with chronic lumbar back pain were graded radiologically using a wide range of classification and measurement systems. The reported effect of facet joint injections at the site was recorded, and a comparative analysis performed. Results When we allocated patients according to their reported pain relief, 27 showed no improvement (0–30%), 16 reported good improvement (31–75%) and 7 reported excellent improvement (> 75%). MRI features assessed in this study did, however, not show any relevant correlation with reported pain after facet joint infiltration: Values for Kendall’s tau ranged from τ = − 0.190 for neuroforaminal stenosis grading as suggested by Lee, to τ = 0.133 for posterior disc height as proposed by Hasegawa. Conclusion Despite the trend in evidence-based medicine to provide medical algorithms, our findings underline the continuing need for individualised spine care that, along with imaging techniques or targeted infiltrations, includes diagnostic dimensions such as good patient history and clinical examination to formulate a diagnosis. Trial registration ClinicalTrials.gov, NCT03308149, retrospectively registered October 2017 Electronic supplementary material The online version of this article (10.1186/s13018-017-0685-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ulf Krister Hofmann
- Department of Orthopaedic Surgery, University Hospital of Tübingen, Hoppe-Seyler-Strasse 3, 72076, Tübingen, Germany.
| | - Ramona Luise Keller
- Faculty of Medicine, Julius-Maximilians University of Würzburg, Josef-Schneider-Str.2, 97080, Würzburg, Germany
| | - Christian Walter
- Department of Orthopaedic Surgery, University Hospital of Tübingen, Hoppe-Seyler-Strasse 3, 72076, Tübingen, Germany
| | - Falk Mittag
- Department of Orthopaedic Surgery, University Hospital of Tübingen, Hoppe-Seyler-Strasse 3, 72076, Tübingen, Germany
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Byrne FA, Keller RL, Meadows J, Miniati D, Brook MM, Silverman NH, Moon-Grady AJ. Severe left diaphragmatic hernia limits size of fetal left heart more than does right diaphragmatic hernia. Ultrasound Obstet Gynecol 2015; 46:688-694. [PMID: 25597867 DOI: 10.1002/uog.14790] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2014] [Revised: 12/05/2014] [Accepted: 01/12/2015] [Indexed: 06/04/2023]
Abstract
OBJECTIVES To assess whether severity of congenital diaphragmatic hernia (CDH) correlates with the degree of left heart hypoplasia and left ventricle (LV) output, and to determine if factors leading to abnormal fetal hemodynamics, such as compression and reduced LV preload, contribute to left heart hypoplasia. METHODS This was a retrospective cross-sectional study of fetuses at 16-37 weeks' gestation that were diagnosed with CDH between 2000 and 2010. Lung-to-head ratio (LHR), liver position and side of the hernia were determined from stored ultrasound images. CDH severity was dichotomized based on LHR and liver position. The dimensions of mitral (MV) and aortic (AV) valves and LV were measured, and right and left ventricular outputs were recorded. RESULTS In total, 188 fetuses with CDH were included in the study, 171 with left CDH and 17 with right CDH. Fetuses with severe left CDH had a smaller MV (Z = -2.24 ± 1.3 vs -1.33 ± 1.08), AV (Z = -1.39 ± 1.21 vs -0.51 ± 1.05) and LV volume (Z = -4.23 ± -2.71 vs -2.08 ± 3.15) and had lower LV output (26 ± 10% vs 32 ± 10%) than those with mild CDH. MV and AV in fetuses with right CDH (MV, Z = -0.83 ± 1.19 and AV, Z = -0.71 ± 1.07) were larger than those in fetuses with left CDH, but LV outputs were similarly diminished, regardless of hernia side. Severe dextroposition and abnormal liver position were associated independently with smaller left heart, while LHR was not. CONCLUSION The severity of left heart hypoplasia correlates with the severity of CDH. Altered fetal hemodynamics, leading to decreased LV output, occurs in both right- and left-sided CDH, but the additional compressive effect on the left heart is seen only when the hernia is left-sided. Improved knowledge of the physiology of this disease may lead to advances in therapy and better risk assessment for use in counseling affected families.
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Affiliation(s)
- F A Byrne
- Department of Pediatrics, Divisions of Cardiology, University of California, Benioff Children's Hospital, San Francisco, CA, USA
| | - R L Keller
- Department of Pediatrics, Division of Neonatology, University of California, Benioff Children's Hospital, San Francisco, CA, USA
| | - J Meadows
- Department of Pediatrics, Divisions of Cardiology, University of California, Benioff Children's Hospital, San Francisco, CA, USA
| | - D Miniati
- Department of Surgery, Division of Pediatric Surgery, University of California, San Francisco, CA, USA
- Fetal Treatment Center, University of California, San Francisco, CA, USA
| | - M M Brook
- Department of Pediatrics, Divisions of Cardiology, University of California, Benioff Children's Hospital, San Francisco, CA, USA
| | - N H Silverman
- Department of Pediatrics, Divisions of Cardiology, University of California, Benioff Children's Hospital, San Francisco, CA, USA
| | - A J Moon-Grady
- Department of Pediatrics, Divisions of Cardiology, University of California, Benioff Children's Hospital, San Francisco, CA, USA
- Fetal Treatment Center, University of California, San Francisco, CA, USA
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Abstract
REASONS FOR PERFORMING STUDY Bacterial ulcerative keratitis is a common and often vision-threatening problem in horses. Emerging bacterial resistance to commonly used topical antibiotics has been demonstrated. Previous antibiotic use may alter the antimicrobial susceptibility of bacterial isolates. OBJECTIVES To document aerobic bacterial isolates and associated bacterial susceptibilities from horses with ulcerative keratitis treated at the University of Tennessee between January 1993 and May 2004 and determine whether prior antibiotic therapy affected antimicrobial susceptibility of the isolates. METHODS Medical records from horses with ulcerative keratitis and positive aerobic bacterial cultures and antimicrobial susceptibility were evaluated. Clinical history regarding antibiotic therapy prior to culture was documented. RESULTS Fifty-one aerobic bacterial isolates from 43 horses were identified. Streptococcus equi subspecies zooepidemicus was the most commonly isolated organism, accounting for 33.3% of all isolates, followed by Pseudomonas aeruginosa (11.8%), Staphylococcus spp. (11.8%) and Gram-negative nonfermenting rods (7.8 %). No resistance was noted amongst S. equi ssp. zooepidemicus to cephalothin, chloramphenicol or ciprofloxacin. Only 64 % of S. equi ssp. zooepidemicus isolates were sensitive to bacitracin. No resistance was noted among P. aeruginosa to gentamicin, tobramycin or ciprofloxacin. Antibiotic therapy with neomycin-polymixin B-bacitracin prior to presentation and culture was documented in 11/17 horses in which S. equi ssp. zooepidemicus was isolated and in 4/6 horses in which P. aeruginosa was isolated. Three horses received topical corticosteroids prior to culture, of which 2 had polymicrobial infections. CONCLUSIONS S. equi ssp. zooepidemicus and P. aeruginosa were the most frequently isolated bacterial organisms in equine ulcerative keratitis. No significant trends in aminoglycoside or fluoroquinolone resistance were noted among these organisms. However, the resistance of S. equi ssp. zooepidemicus to bacitracin with common use of this antibiotic suggests that previous antibiotic therapy probably affects antimicrobial resistance. POTENTIAL RELEVANCE Therapy prior to culture may play an important role in antimicrobial susceptibility of corneal bacterial isolates. Corticosteroid use may increase the risk of polymicrobial infections of corneal ulcers, leading to a worse prognosis. Although significant fluoroquinolone resistance has not been documented in the veterinary literature, these antimicrobials should be reserved for known infected corneal ulcers and not used for prophylaxis. Empirical antibiotic therapy should not only be guided by clinical signs, but also take into consideration previous antimicrobial and corticosteroid therapy.
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Affiliation(s)
- R L Keller
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, C247 Veterinary Teaching Hospital, Knoxville, Tennessee 37996-4544, USA
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Jani J, Nicolaides KH, Keller RL, Benachi A, Peralta CFA, Favre R, Moreno O, Tibboel D, Lipitz S, Eggink A, Vaast P, Allegaert K, Harrison M, Deprest J. Observed to expected lung area to head circumference ratio in the prediction of survival in fetuses with isolated diaphragmatic hernia. Ultrasound Obstet Gynecol 2007; 30:67-71. [PMID: 17587219 DOI: 10.1002/uog.4052] [Citation(s) in RCA: 364] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
OBJECTIVE To assess the value of antenatally determined observed to expected fetal lung area to head circumference ratio (LHR) in the prediction of postnatal survival in isolated, congenital diaphragmatic hernia (CDH). METHODS Two groups of fetuses were examined. The first group included 650 normal fetuses at 12-32 weeks' gestation, and the data collected were used to establish a normal range of observed to expected LHR with gestational age. The second group included the data of a retrospective multicenter study of 354 fetuses with isolated CDH in which the LHR was measured on one occasion at 18-38 weeks' gestation. The patients were divided into those with left-sided CDH with and without intrathoracic herniation of the liver and right-sided CDH. Regression analysis was used to determine the significant predictors of postnatal survival. RESULTS In both the normal fetuses and those with CDH the LHR increased but the observed to expected LHR did not change significantly with gestational age. In normal fetuses the mean observed to expected LHR in the left lung was 100% (95% CI, 61-139%) and in the right lung it was 100% (95% CI, 67-133%). In fetuses with CDH the mean observed to expected LHR was 39% (range 7-79%). Regression analysis demonstrated that significant predictors of survival were the observed to expected LHR (odds ratio (OR) 1.09, 95% CI, 1.06-1.12), side of CDH (left side OR 11.14, 95% CI, 3.41-36.39) and gestational age at delivery (OR 1.18, 95% CI, 1.02-1.36). CONCLUSION In CDH, the LHR increases while observed to expected LHR is independent of gestational age. In fetuses with both left- and right-sided CDH, measurement of the observed to expected LHR provides a useful prediction of subsequent survival.
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Affiliation(s)
- J Jani
- Fetal Medicine and Treatment Units, University Hospital Gasthuisberg, Leuven, Belgium
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Abstract
OBJECTIVE To compare the incidence of chronic lung disease (CLD) in extremely low birth weight (ELBW, < or =1000 g) infants before and after the introduction of early, preferential application of nasal continuous airway pressure (NCPAP) utilizing a variable flow delivery system. STUDY DESIGN A retrospective cohort study of ELBW infants 2 years prior to (Pre-early NCPAP, n=96) and 2 years following (Early NCPAP, n=75) the initiation of an early NCPAP policy. RESULTS There were no significant changes (Pre-early NCPAP vs Early NCPAP) in the incidences of CLD (35 vs 33%, P=0.81) or CLD or death (50 vs 43%, P=0.34). Infants in the Early NCPAP group weaned off mechanical ventilation and supplemental oxygen more rapidly than infants in the Pre-early NCPAP group (hazard ratio (HR) 1.80, P=0.002 and HR 1.69, P=0.01). CONCLUSION A policy of early NCPAP has not decreased the incidence of CLD despite a decrease in time to successful tracheal extubation.
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Affiliation(s)
- P Jegatheesan
- Department of Pediatrics, University of California San Francisco, CA 94143-0748, USA
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Jani J, Keller RL, Benachi A, Nicolaides KH, Favre R, Gratacos E, Laudy J, Eisenberg V, Eggink A, Vaast P, Deprest J. Prenatal prediction of survival in isolated left-sided diaphragmatic hernia. Ultrasound Obstet Gynecol 2006; 27:18-22. [PMID: 16374756 DOI: 10.1002/uog.2688] [Citation(s) in RCA: 143] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
OBJECTIVE To investigate the potential value of antenatally determined intrathoracic herniation of the liver and the ratio of fetal lung area to head circumference (LHR) in the prediction of postnatal survival in isolated, left-sided congenital diaphragmatic hernia (CDH). METHODS In this multicenter study, we searched the antenatal-CDH-Registry for fetuses with isolated left-sided CDH that were liveborn after 30 weeks of gestation and were followed up postnatally for at least 3 months after discharge from hospital. The patients were subdivided into those with and those without intrathoracic herniation of the liver and into subgroups according to the LHR that had been measured between 22 + 0 and 28 + 0 weeks of gestation. The rate of survival in each group and subgroup of patients was determined and compared. RESULTS The registry search identified 184 patients that fulfilled the entry criteria. Logistic regression analysis demonstrated that significant predictors of survival were the presence or absence of intrathoracic herniation of the liver and the LHR. In 86 cases there was liver herniation (Group A) and in 98 the liver was confined to the abdomen (Group B). In Group A, the survival rate was 50.0% and was significantly associated with LHR; in Group B the survival rate was 76.5% and was unrelated to LHR. CONCLUSION In isolated, left-sided CDH, the postnatal mortality rate is substantially higher if there is intrathoracic herniation of the liver. In fetuses with liver herniation, measurement of LHR at 22-28 weeks of gestation is useful in the prediction of subsequent survival.
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Affiliation(s)
- J Jani
- Fetal Medicine and Treatment Units of the University Hospital Gasthuisberg, Leuven, Belgium
| | - R L Keller
- Fetal Medicine and Treatment Units of the University of California at San Francisco, San Francisco, CA, USA
| | - A Benachi
- Fetal Medicine and Treatment Units of the Hôpital Necker-Enfants Malades, Paris, France
| | - K H Nicolaides
- Fetal Medicine and Treatment Units of the King's College Hospital, London, UK
| | - R Favre
- Fetal Medicine and Treatment Units of the CMCO de Schiltigheim, Strasbourg, France
| | - E Gratacos
- Fetal Medicine and Treatment Units of the Vall d'Hebron Hospital, Barcelona, Spain
| | - J Laudy
- Fetal Medicine and Treatment Units of the Erasmus Medical Center, Rotterdam, The Netherlands
| | - V Eisenberg
- Fetal Medicine and Treatment Units of the Sheba Medical Center, Tel Hashomer, Israel
| | - A Eggink
- Fetal Medicine and Treatment Units of the UMC Sint Radboud, Nijmegen, The Netherlands
| | - P Vaast
- Fetal Medicine and Treatment Units of the Hôpital Jeanne de Flandre, CHRU Lille, France
| | - J Deprest
- Fetal Medicine and Treatment Units of the University Hospital Gasthuisberg, Leuven, Belgium
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Keller RL, Glidden DV, Paek BW, Goldstein RB, Feldstein VA, Callen PW, Filly RA, Albanese CT. The lung-to-head ratio and fetoscopic temporary tracheal occlusion: prediction of survival in severe left congenital diaphragmatic hernia. Ultrasound Obstet Gynecol 2003; 21:244-249. [PMID: 12666218 DOI: 10.1002/uog.44] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
OBJECTIVES To evaluate the reliability of sonographic lung-to-head ratio (LHR) measurement as a predictor of survival in fetuses with congenital diaphragmatic hernia (CDH) and to compare the probability of survival in those with temporary tracheal occlusion (TO) or standard care with respect to the LHR. METHODS Fifty-six fetuses with left CDH with liver herniated into the thorax at complete prenatal evaluation were included in logistic regression analyses of antenatal predictors of survival to hospital discharge. Sixteen subjects underwent TO and 40 received standard care. RESULTS LHR was a significant predictor of survival, with probability of survival increasing with increasing LHR (odds ratio (OR) 8.5, P = 0.04). When subjects with anomalies were excluded, the LHR effect was similar after adjustment for TO (OR 7.1, P = 0.11). Linear spline models suggested a plateau in survival at an LHR of 1.0 and all models suggested increased odds of survival with TO. Minimum LHR measurements had a high degree of inter- and intraobserver agreement (intraclass correlation coefficients of 0.70 and 0.80, respectively). CONCLUSIONS Calculation of the LHR in fetuses with CDH is a reliable and powerful predictor of survival to hospital discharge, although improving odds of survival may plateau at an LHR of 1.0. TO may have an independent benefit on survival to hospital discharge.
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Affiliation(s)
- R L Keller
- Department of Pediatrics and the Cardiovascular Research Institute, The Fetal Treatment Center, University of California San Francisco, San Francisco, CA 94143, USA
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Hays AM, Keller RL, Gmitro AF, Alpbach MI, Sridhar KR, Balagtas MP, Witten ML. Quantitative phase contrast images to quantitate flow in a rat model of microgravity. Aviat Space Environ Med 1999; 70:225-9. [PMID: 10102733] [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: 04/12/2023]
Abstract
A magnetic resonance angiographic (MRA) technique for noninvasive measurement of flow in the inferior vena cava (IVC) was used to study blood flow changes in a simulated microgravity model. Microgravity was simulated in adult male Fischer 344 rats (n = 12, with each rat acting as its own control) using a tail harness to elevate the hindquarters, producing a non-weight bearing hindlimb (NWH) model. Quantitative phase contrast images of flow within the IVC were obtained initially and after a 2-week NWH protocol. Inferior vena cava blood flow was determined by converting the intensity at the respective magnetic resonance pixels into a corresponding flow by Doppler techniques. Average values for flow determined with MR angiography were 351.8 (SEM = 49) mm3 x s(-1) initially and 524.5 (SEM = 46) mm3 x s(-1) after exposure to 2 weeks of the NWH protocol. Post 2-week NWH flow increased 49.1% over the initial NWH value. Using a paired t-test, a significant difference was found between the rats' IVC flow values in the initial and post-NWH groups (p < 0.004). The changes in IVC blood flow due to 45 degrees NWH may contribute to the overall changes observed in the cardiovascular system during simulated microgravity.
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Affiliation(s)
- A M Hays
- Department of Pediatrics, University of Arizona Health Sciences Center, Tucson 85724-0001, USA
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Witten ML, Balagtas MP, Keller RL, Hays AM, Braun EJ, Vargas J, Padilla MT, Hall JN. Response to 45 degrees head-down tilt as measured by organ weight/body weight ratios and spiral computed tomography. Aviat Space Environ Med 1999; 70:11-4. [PMID: 9895015] [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: 02/09/2023]
Abstract
BACKGROUND Exposure to microgravity or simulated microgravity causes significant shifts in body fluids which may initiate physiological adaptations to the microgravity stressor. It is imperative to understand the physiological adaptations to microgravity in order to develop appropriate countermeasures to the deleterious aspects (i.e., muscle and bone wasting) of long-term spaceflights. HYPOTHESIS The significant shifts in body fluids by 45 degrees head-down tilt can be measured by changes in organ weight/body weight (OW/BW) ratios and non-invasively by spiral computed tomography. METHODS In a previous study (14), rats were weighed and exposed to either 45 degrees head-down tilt (45HDT) or a prone control position for one of the following experimental times: 0.5 h, 1 h, 2 h, 4 h, 8 h, or 24 h. A radioactive tracer was injected intramuscularly immediately prior to the start of the experimental time periods. At the end of the experiment, the major organs were harvested, weighed, and measured for gamma radiation levels. We used the organ weights from this previous study to calculate OW/BW ratios for the present study. Additionally, in the present study, rats in the 14-d experimental groups were weighed, lightly anesthetized to facilitate placement in the 45HDT position, and placed in a specially designed 45HDT cage (45HDT group) or left unrestrained in the cages (control group). At the end of the 14-d experimental time period, the rats were anesthetized and their lung densities measured with spiral computed tomography. RESULTS The OW/BW ratios for the liver, kidneys, and spleen of 24 h 45HDT rats were significantly lower (p<0.05) than control values while at 1 h the 45HDT rats had a higher kidney OW/BW ratio. Lung density from the 14-d 45HDT rats was 24.4% greater than control rats' values. CONCLUSIONS The physiological change due to the 45HDT position to simulate microgravity begins as early as 1 h, and the kidney appears to be the first organ affected. Spiral computed tomography may offer a viable method of non-invasively measuring organ densities in the 45HDT model. The OW/BW data generated in the present study does not correlate with the changes in radioactive tracer distribution data from our previous study.
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Affiliation(s)
- M L Witten
- Department of Pediatrics and Steele Memorial Children's Research Center, University of Arizona College of Medicine, Tucson, USA
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Dennehy EB, Edwards CA, Keller RL. AIDS education intervention utilizing a person with AIDS: examination and clarification. AIDS Educ Prev 1995; 7:124-133. [PMID: 7619643] [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: 05/21/2023]
Abstract
The utility of a person with AIDS (PWA) in conveying AIDS information to college students is assessed. Mode of transmission of HIV is proposed to serve as a moderating variable in students' receptivity to the AIDS information and perception of the source of AIDS information. Two-hundred-sixty undergraduate students received a standardized lecture by a confederate, posing as a PWA, who revealed HIV positive status through either heterosexual transmission, homosexual transmission, needle-sharing, or a blood transfusion. Control conditions received the lecture from a neutral presenter (no HIV status disclosure) or no contact. All the HIV conditions were superior to the Control condition in increasing knowledge about AIDS and AIDS prevention. Additionally, students rated the PWA more positively than the neutral presenter on a number of evaluative dimensions. Mode of transmission served a mediating effect, with the confederate viewed most favorably in the Heterosexual and Transfusion conditions, and less favorably in the i.v. Drug and Homosexual conditions. Implications for educational programs are discussed.
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Affiliation(s)
- E B Dennehy
- Department of Psychology, University of North Carolina at Wilmington 28403, USA
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