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Lockwood J, Khan P, Zeoli T, Maulucci CM. Intradural extramedullary metastatic melanoma: A case report and review of the literature. Clin Neurol Neurosurg 2020; 197:106072. [PMID: 32731084 DOI: 10.1016/j.clineuro.2020.106072] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 06/27/2020] [Accepted: 07/05/2020] [Indexed: 10/23/2022]
Affiliation(s)
- J Lockwood
- Tulane Medical Center, Department of Neurosurgery, New Orleans, LA, USA.
| | - P Khan
- Tulane Medical Center, Department of Neurosurgery, New Orleans, LA, USA.
| | - T Zeoli
- Tulane Medical Center, Department of Neurosurgery, New Orleans, LA, USA.
| | - C M Maulucci
- Tulane Medical Center, Department of Neurosurgery, New Orleans, LA, USA.
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Drozd K, Deng Y, Jiang B, Lockwood J, Thorn S, Klein R, Stewart D, Beanlands R, deKemp R, DaSilva J, Mielniczuk L. Elevated Fatty Acid and Glucose Uptake in Right Ventricle in a Sugen 5416/Hypoxia Rat Model of Severe Pulmonary Artery Hypertension. Can J Cardiol 2013. [DOI: 10.1016/j.cjca.2013.07.404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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Galea R, Wells RG, Ross CK, Lockwood J, Moore K, Harvey JT, Isensee GH. A comparison of rat SPECT images obtained using (99m)Tc derived from 99Mo produced by an electron accelerator with that from a reactor. Phys Med Biol 2013; 58:2737-50. [PMID: 23552053 DOI: 10.1088/0031-9155/58/9/2737] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Recent shortages of molybdenum-99 ((99)Mo) have led to an examination of alternate production methods that could contribute to a more robust supply. An electron accelerator and the photoneutron reaction were used to produce (99)Mo from which technetium-99m ((99m)Tc) is extracted. SPECT images of rat anatomy obtained using the accelerator-produced (99m)Tc with those obtained using (99m)Tc from a commercial generator were compared. Disks of (100)Mo were irradiated with x-rays produced by a 35 MeV electron beam to generate about 1110 MBq (30 mCi) of (99)Mo per disk. After target dissolution, a NorthStar ARSII unit was used to separate the (99m)Tc, which was subsequently used to tag pharmaceuticals suitable for cardiac and bone imaging. SPECT images were acquired for three rats and compared to images for the same three rats obtained using (99m)Tc from a standard reactor (99)Mo generator. The efficiency of (99)Mo-(99m)Tc separation was typically greater than 90%. This study demonstrated the delivery of (99m)Tc from the end of beam to the end user of approximately 30 h. Images obtained using the heart and bone scanning agents using reactor and linac-produced (99m)Tc were comparable. High-power electron accelerators are an attractive option for producing (99)Mo on a national scale.
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Affiliation(s)
- R Galea
- Ionizing Radiation Standards, National Research Council, 1200 Montreal Road, Ottawa, ON K1A0R6, Canada.
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Papaevangelou V, Quinlivan M, Lockwood J, Papaloukas O, Sideri G, Critselis E, Papassotiriou I, Papadatos J, Breuer J. Subclinical VZV reactivation in immunocompetent children hospitalized in the ICU associated with prolonged fever duration. Clin Microbiol Infect 2013; 19:E245-51. [PMID: 23331898 DOI: 10.1111/1469-0691.12131] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Revised: 12/06/2012] [Accepted: 12/13/2012] [Indexed: 11/28/2022]
Abstract
A prospective observational study was conducted to examine whether asymptomatic VZV reactivation occurs in immunocompetent children hospitalized in an ICU and its impact on clinical outcome. A secondary aim was to test the hypothesis that vaccinated children have a lower risk of reactivation than naturally infected children. Forty immunocompetent paediatric ICU patients and healthy controls were enrolled. Patients were prospectively followed for 28 days. Clinical data were collected and varicella exposure was recorded. Admission serum levels of TNF-a, cortisol and VZV-IgG were measured. Blood and saliva samples were collected for VZV-DNA detection via real-time PCR. As a comparison, the detection of HSV-DNA was also examined. Healthy children matched for age and varicella exposure type (infection or vaccination) were also included. VZV reactivation was observed in 17% (7/39) of children. Children with VZV reactivation had extended duration of fever (OR = 1.17; 95% CI, 1.02-1.34). None of the varicella-vaccinated children or healthy controls had detectable VZV-DNA in any blood or saliva samples examined. HSV-DNA was detected in saliva from 33% of ICU children and 2.6% of healthy controls. Among children with viral reactivation, typing revealed wild-type VZV and HSV-1. In conclusion, VZV reactivation occurs in immunocompetent children under severe stress and is associated with prolonged duration of fever.
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Affiliation(s)
- V Papaevangelou
- Second Department of Pediatrics, National and Kapodistrian University of Athens School of Medicine, Athens, Greece.
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Wells RG, Lockwood J, Wei L, Duan D, Fernando P, Bensimon C, Ruddy TD. Sci-Fri AM: Imaging - 09: Serial estimation of cross-talk for correction in dual-isotope imaging with dynamic tracers. Med Phys 2012; 39:4642. [PMID: 28516654 DOI: 10.1118/1.4740195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The recent radioisotope shortage has led to interest in non-Tc99m-based tracers. We have developed a novel I-123-labelled myocardial perfusion imaging tracer. We compare the I123-tracer to the clinical standard of Tc99m tetrofosmin in vivo in a rat model using a small-animal SPECT/CT camera. SPECT distinguishes different isotopes based on the different energies of the emitted gamma rays and thus allows simultaneous comparison of two tracer distributions in the same animal. Dual-isotope imaging is complicated by cross-talk between the energy windows of the isotopes. Standard energy-window-based correction methods are difficult to employ because of the proximity in energy of Tc99m (140keV) and I123 (159keV). Imaging the second tracer's energy window prior to its injection provides an estimate of the cross-talk. However, this estimate is only accurate if the tracer distribution is static. We use serial imaging prior to the introduction of the second tracer to estimate the dynamics of the first tracer and interpolate the cross-talk images to provide a more accurate correction. We used rat models of myocardial disease (n=3). I123 tracer was injected and imaged for one hour at 20min intervals. The Tc99m tetrofosmin was then injected and 30min later, a dual-isotope image was obtained. The impact of this approach is assessed by comparing the differences in the Tc99m-tetrofosmin image using this method with correction by simple correction for physical decay. The interpolative approach improves the accuracy of the correction by 2%-5% and thereby enhances the comparison of the two tracers.
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Affiliation(s)
- R G Wells
- Cardiology, The University of Ottawa Heart Institute, Ottawa, ON
| | - J Lockwood
- Cardiology, The University of Ottawa Heart Institute, Ottawa, ON
| | | | | | | | | | - T D Ruddy
- Cardiology, The University of Ottawa Heart Institute, Ottawa, ON
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Strydhorst J, Lockwood J, Wells RG. Poster - Thur Eve - 69: Attenuation Correction for 99m
Tc-Tetrofosmin Micro SPECT/CT Cardiac Measurements in Rats. Med Phys 2010. [DOI: 10.1118/1.3476174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Nahin MF, Lockwood J, Strydhorst J, Kordos M, Ruddyence TD, Wells RG. Poster - Thur Eve - 53: Reproducibility of TI-201 for Cardiac Micro SPECT Imaging with a Rat Model. Med Phys 2010. [DOI: 10.1118/1.3476158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Fraas M, Lockwood J, Neils-Strunjas J, Shidler M, Krikorian R, Weiler E. 'What's his name?' A comparison of elderly participants' and undergraduate students' misnamings. Arch Gerontol Geriatr 2004; 34:155-65. [PMID: 14764319 DOI: 10.1016/s0167-4943(01)00206-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2001] [Revised: 10/09/2001] [Accepted: 10/10/2001] [Indexed: 11/22/2022]
Abstract
This study examined the effects of age on the types of errors produced when recalling names of faces. The types of errors included confusions (errors within the target set), intrusions (errors outside the target set), errors phonologically similar to the target, errors not phonologically similar to the target, and errors containing the same number of syllables as the target name. Participants included 49 elderly adults (57-85 years) and 48 undergraduate students (18-44 years). Age group had a significant effect on the number of name errors produced (n=681 for elderly and n=422 for undergraduates). Elderly participants produced more confusions than their younger counterparts; however, younger participants produced significantly more intrusions. The age groups also differed in their production of error names that were phonologically similar to the target name. The elderly participants produced more errors that were not phonologically similar to the target than the young adults. The results are discussed with regard to theories of name-face association and tip-of-the-tongue phenomena.
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Affiliation(s)
- M Fraas
- Department of Communication Disorders, University of Cincinnati, ML#379, Cincinnati, OH 45207, USA
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Ramadurai L, Lockwood KJ, Lockwood J, Nadakavukaren MJ, Jayaswal RK. Characterization of a chromosomally encoded glycylglycine endopeptidase of Staphylococcus aureus. Microbiology (Reading) 1999; 145 ( Pt 4):801-808. [PMID: 10220159 DOI: 10.1099/13500872-145-4-801] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The authors previously reported the cloning of a lytic-enzyme-encoding gene, lytM, from an autolysis-defective mutant of Staphylococcus aureus. In the present work, the lytM gene was overexpressed in Escherichia coli and the product was purified to homogeneity by affinity chromatography and HPLC. Biochemical analysis of LytM-cleaved peptidoglycan fragments indicated that LytM is a glycylglycine endopeptidase. Immunoelectron microscopic studies with anti-LytM rabbit IgG showed that LytM is expressed during the early exponential phase and is overexpressed in an autolysis-defective mutant compared with the parent strain. Also, a uniform distribution of gold particles on the surface of actively growing bacterial cells indicates that LytM plays a role in cell growth. Northern blot analyses of lytM expression in two global regulatory mutants, agr and sar, showed that expression of lytM is increased about twofold in these mutants as compared with the parents. Protein homology searches revealed that LytM could be a member of the zinc protease family, as it contained a homologous 38-amino-acid motif, Tyr-X-His-X11-Val-X12/20-Gly-X5-6-His. Atomic absorption spectrometric analysis of LytM revealed the presence of 0.9 mol zinc (mol LytM)(-1).
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Weidenspointner G, Bennett K, van Dijk R, Kappadath SC, Lockwood J, Morris D, Schonfelder V, Varendorff M. The local neutron flux at low Earth-orbiting altitudes. Adv Space Res 1998; 21:1781-1784. [PMID: 11542899 DOI: 10.1016/s0273-1177(98)00066-0] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The COMPTEL instrument onboard the Compton Gamma Ray Observatory (CGRO) has been used to measure the variation of the atmospheric neutron flux below 5 MeV as a function of vertical cutoff rigidity and spacecraft orientation at an altitude of 450 km. The instrumental 2.2 MeV background line, resulting from thermal neutron capture on hydrogen, was used for the measurement. The dependence of the 2.2 MeV rate on rigidity and geocentre zenith can be described by an analytic function: the line rate decreases linearly with geocentre zenith, and decreases exponentially with the vertical cutoff rigidity. The flux varies on average by about a factor of 3.7 between the extremes in rigidity, and by a factor of 1.7 between the extremes of spacecraft orientation with respect to the Earth. We believe that mass shielding is more important in attenuating the atmospheric albedo than as a source of secondary neutrons. The COMPTEL instrument is well suited for a long-duration study of the dependence of the neutron flux on the vertical cutoff rigidity and the solar cycle.
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Affiliation(s)
- G Weidenspointner
- Max Planck Institut fur Extraterrestrische Physik, Garching, Germany
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Abstract
A previous study has reported benefit when pyridoxine hydrochloride was given to patients with atopic dermatitis. To investigate this in children, we performed a randomized, double-blind, parallel-group, placebo-controlled trial. Forty-eight children with moderate or severe atopic dermatitis were recruited and, of those who completed the study, 19 received pyridoxine hydrochloride 50 mg once daily for 4 weeks and 22 received placebo. Disease activity was monitored by clinical severity scores measuring the extent and degrees of erythema recorded by the investigator and symptom scores (daytime itch and nocturnal sleep disturbance) recorded by parents. There was no statistically significant difference between the two groups at the end of treatment. We have been unable to demonstrate clinical benefit from pyridoxine supplementation in children with atopic dermatitis.
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Affiliation(s)
- D C Mabin
- Department of Child Health, University of Manchester, Booth Hall Children's Hospital, Blackley, U.K
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Bender M, Simmonds J, Lockwood J. An active solution for health. Elder Care 1995; 7:20, 22-3. [PMID: 7647749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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Rama Rao G, Cain CA, Lockwood J, Tompkins WA. Effects of microwave exposure on the hamster immune system. II. Peritoneal macrophage function. Bioelectromagnetics 1983; 4:141-55. [PMID: 6223642 DOI: 10.1002/bem.2250040205] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Acute exposure to hamsters to microwave energy (2.45 GHz; 25 mW/cm2 for 60 min) resulted in activation of peritoneal macrophages that were significantly more viricidal to vaccinia virus as compared to sham-exposed or normal (minimum-handling) controls. Macrophages from microwave-exposed hamsters became activated as early as 6 h after exposure and remained activated for up to 12 days. The activation of macrophages by microwave exposure paralleled the macrophage activation after vaccinia virus immunization. Activated macrophages from vaccinia-immunized hamsters did not differ in their viricidal activity when the hamsters were microwave- or sham-exposed. Exposure for 60 min at 15 mW/cm2 did not activate the macrophages while 40 mW/cm2 exposure was harmful to some hamsters. Average maximum core temperatures in the exposed (25 mW/cm2) and sham groups were 40.5 degrees C (+/- 0.35 SD) and 38.4 degrees C (+/- 0.5 SD), respectively. In vitro heating of macrophages to 40.5 degrees C was not as effective as in vivo microwave exposure in activating macrophages to the viricidal state. Macrophages from normal, sham-exposed, and microwave-exposed hamsters were not morphologically different, and they all phagocytosed India ink particles. Moreover, immune macrophage cytotoxicity for virus-infected or noninfected target cells was not suppressed in the microwave-irradiated group (25 mW/cm2, 1 h) as compared to sham-exposed controls, indicating that peritoneal macrophages were not functionally suppressed or injured by microwave hyperthermia.
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Yang HK, Cain CA, Lockwood J, Tompkins WA. Effects of microwave exposure on the hamster immune system. I. Natural killer cell activity. Bioelectromagnetics 1983; 4:123-39. [PMID: 6870966 DOI: 10.1002/bem.2250040204] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Hamsters were exposed to repeated or single doses of microwave energy and monitored for changes in core body temperature, circulating leukocyte profiles, serum corticosteroid levels, and natural killer (NK) cell activity in various tissues. NK cytotoxicity was measured in a 51Cr-release assay employing baby hamster kidney (BHK) targets or BHK infected with herpes simplex virus. Repeated exposure of hamsters at 15 mW/cm2 for 60 min/day had no significant effect on natural levels of spleen-cell NK activity against BHK targets. Similarly, repeated exposure at 15 mW/cm2 over a 5-day period had no demonstrable effect on the induction of spleen NK activity by vaccinia virus immunization, that is, comparable levels of NK were induced in untreated and microwave-treated animals. In contrast, treatment of hamsters with a single 60-min microwave exposure at 25 mW/cm2 caused a significant suppression in induced spleen NK activity. A similar but less marked decrease in spleen NK activity was observed in sham-exposed animals. Moreover, the sham effects on NK activity were not predictable and appeared to represent large individual animal variations in the response to stress factors. Depressed spleen NK activity was evident as early as 4 h postmicrowave treatment and returned to normal levels by 8 h. Hamsters exposed at 25 mW/cm2 showed an elevated temperature of 3.0-3.5 degrees C that returned to normal within 60 min after termination of microwave exposure. These animals also showed a marked lymphopenia and neutrophilia by 1 h posttreatment that returned to normal by 8-10 h. Serum glucocorticosteroids were elevated between 1 aNd 8 h after microwave treatment. Sham-exposed animals did not demonstrate significant changes in core body temperature, peripheral blood leukocyte (PBL) profile, or glucocorticosteroid levels as compared to minimum-handling controls.
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Whur P, Magudia M, Boston J, Lockwood J, Williams DC. Plasminogen activator in cultured Lewis lung carcinoma cells measured by chromogenic substrate assay. Br J Cancer 1980; 42:305-13. [PMID: 7191713 PMCID: PMC2010387 DOI: 10.1038/bjc.1980.231] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
A chromogenic substrate assay for the plasminogen activator (PA) activity of Lewis lung carcinoma cells has been developed. The cells were incubated with plasminogen, the activation of which to plasmin was measured by the amidolysis of the chromogenic substrate S-2251. This was routinely performed as a 4h serum-free assay, but a variation lasting 24 h, in medium supplemented with plasminogen-free inhibitor-reduced serum, produced similar results. The assay also detected PA released into the medium. PA activity was proportional to cell density, and the assay was non-toxic to the cells. Assays were performed on cultures derived from primary and metastatic tumours. Host cells were effectively eliminated from such cultures but, because of an initial phase of tumour-cell death, PA assays were not carried out until cultures became established. No consistent difference was detected between PA levels in primary and metastatic cultures. However, these cultures were shown to be atypical of the parent tumour; they grew slowly when reinjected at the primary site, and their metastatic potential was impaired.
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Pincus WB, Lockwood J. Cytotoxic factor formation from tuberculin-sensitive guinea pigs. Am Rev Respir Dis 1968; 98:250-259. [PMID: 5667752 DOI: 10.1164/arrd.1968.98.2.250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
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