Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 10 de 10
Filter
Add more filters










Publication year range
1.
Diagn Interv Imaging ; 101(5): 269-279, 2020 May.
Article in English | MEDLINE | ID: mdl-32107196

ABSTRACT

PURPOSE: The purpose of this study was to analyze the impact of different options for reduced-dose computed tomography (CT) on image noise and visibility of pulmonary structures in order to define the best choice of parameters when performing ultra-low dose acquisitions of the chest in clinical routine. MATERIALS AND METHODS: Using an anthropomorphic chest phantom, CT images were acquired at four defined low dose levels (computed tomography dose index [CTDIvol]=0.15, 0.20, 0.30 and 0.40mGy), by changing tube voltage, pitch factor, or rotation time and adapting tube current to reach the predefined CTDIvol-values. Images were reconstructed using two different levels of iteration (adaptive statistical iterative reconstruction [ASIR®]-v70% and ASIR®-v100%). Signal-to-noise ratio (SNR) as well as contrast-to-noise ratio (CNR) was calculated. Visibility of pulmonary structures (bronchi/vessels) were assessed by two readers on a 5-point-Likert scale. RESULTS: Best visual image assessments and CNR/SNR were obtained with high tube voltage, while lowest scores were reached with lower pitch factor followed by high tube current. Protocols favoring lower pitch factor resulted in decreased visibility of bronchi/vessels, especially in the periphery. Decreasing radiation dose from 0.40 to 0.30mGy was not associated with a significant decrease in visual scores (P<0.05), however decreasing radiation dose from 0.30mGy to 0.15mGy was associated with a lower visibility of most of the evaluated structures (P<0.001). While image noise could be significantly reduced when ASIR®-v100% instead of ASIR®-v70% was used, the visibility-scores of pulmonary structures did not change significantly. CONCLUSION: Favoring high tube voltage is the best option for reduced-dose protocols. A decrease of SNR and CNR does not necessarily go along with reduced visibility of pulmonary structures.


Subject(s)
Radiographic Image Interpretation, Computer-Assisted , Tomography, X-Ray Computed , Algorithms , Humans , Phantoms, Imaging , Radiation Dosage , Signal-To-Noise Ratio
2.
Eye (Lond) ; 28(11): 1321-7, 2014 Nov.
Article in English | MEDLINE | ID: mdl-25190533

ABSTRACT

PURPOSE: To evaluate the impact of myopic keratorefractive surgery on ocular alignment. METHODS: This prospective study included 194 eyes of 97 myopic patients undergoing laser refractive surgery. All patients received a complete ophthalmic examination with particular attention to ocular alignment before and 3 months after surgery. RESULTS: Patients with a mean age of 26.6 years and a mean refractive error of -4.83 diopters (D) myopia were treated. Asymptomatic ocular misalignment was present preoperatively in 46 (47%) patients: a small-angle heterophoria (1-8 prism diopters, PD) in 36%; and a large-angle heterophoria (>8 PD)/heterotropia in 11%. Postoperatively, the change in angles of 10 PD or greater occurred in 3% for distance and 6% for near fixation: in 7% of the patients with orthophoria, in 3% of those with a small-angle heterophoria, and in 18% of those with a large-angle heterophoria/heterotropia. No patient developed diplopia. The preoperative magnitude of myopia or postoperative refractive status was not related to the change in ocular alignment. The higher anisometropia was associated with a decrease in deviation (P=0.041 for distance and P=0.002 for near fixation), whereas the further near point of convergence tended to be related with an increase in near deviation (P=0.055). CONCLUSIONS: Myopic refractive surgery may cause a change in ocular alignment, especially in cases with a large-angle heterophoria/heterotropia. There is also a chance of improvement of misalignment in patients with anisometropia.


Subject(s)
Anisometropia/physiopathology , Cornea/physiopathology , Keratectomy, Subepithelial, Laser-Assisted/methods , Keratomileusis, Laser In Situ/methods , Myopia/surgery , Vision, Binocular/physiology , Adult , Depth Perception/physiology , Female , Humans , Male , Myopia/physiopathology , Prospective Studies , Visual Acuity/physiology , Young Adult
3.
Br J Radiol ; 85(1014): e176-81, 2012 Jun.
Article in English | MEDLINE | ID: mdl-21896665

ABSTRACT

OBJECTIVE: The aim of our study was to determine if virtual unenhanced CT (VUCT) is equivalent to unenhanced CT (UCT) for detecting urinary stones. METHODS: Our institutional review board approved this retrospective study, which was compliant with the Health Insurance Portability and Accountability Act. A total of 80 stones were detected in 32 patients among 146 consecutive patients undergoing dual-energy CT urography. The number and size of stones were recorded on nephrographic VUCT (NVUCT) and excretory VUCT (EVUCT) images, respectively. UCT was a reference of standard for the number and size of stones. Image quality of VUCT was qualitatively assessed using a five-point scale. Repeated-measures analysis of variance with post-test was used for statistical analysis. RESULTS: 62 stones in 29 patients were detected on NVUCT and 59 stones in 27 patients were detected on EVUCT. The size of stones detected on NVUCT or EVUCT was significantly smaller compared with stones on UCT (p<0.05). The size of stones detected on UCT, NVUCT and EVUCT ranged from 1.4 to 19.2 mm (mean, 4.6 mm), 0 to 19.2 mm (mean, 3.6 mm) and 0 to 18.7 mm (mean, 3.6 mm), respectively. 18 stones were missed on NVUCT and 21 were missed on EVUCT. The sizes ranged from 1.4 to 3.2 mm (mean, 2.1 mm) and 1.4 to 3.2 mm (mean, 2.2 mm) on UCT, respectively. VUCT was inferior to UCT regarding image quality (p<0.05). CONCLUSION: VUCT missed a significant number of small stones probably owing to poor image quality compared with UCT. Subsequently, VUCT cannot replace UCT for detecting urinary stones.


Subject(s)
Tomography, X-Ray Computed/methods , Urinary Calculi/diagnostic imaging , Adult , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Retrospective Studies , Urography/methods , Young Adult
4.
J Environ Qual ; 35(5): 1715-30, 2006.
Article in English | MEDLINE | ID: mdl-16899743

ABSTRACT

The objective of this study was to determine how structure, stratigraphy, and weathering influence fate and transport of contaminants (particularly U) in the ground water and geologic material at the Department of Energy (DOE) Environmental Remediation Sciences Department (ERSD) Field Research Center (FRC). Several cores were collected near four former unlined adjoining waste disposal ponds. The cores were collected, described, analyzed for U, and compared with ground water geochemistry from surrounding multilevel wells. At some locations, acidic U-contaminated ground water was found to preferentially flow in small remnant fractures weathering the surrounding shale (nitric acid extractable U [U(NA)] usually < 50 mg kg(-1)) into thin (<25 cm) Fe oxide-rich clayey seams that retain U (U(NA) 239 to 375 mg kg(-1)). However, greatest contaminant transport occurs in a 2 to 3 m thick more permeable stratigraphic transition zone located between two less permeable, and generally less contaminated zones consisting of (i) overlying unconsolidated saprolite (U(NA) < 0.01 to 200 mg kg(-1)) and (ii) underlying less-weathered bedrock (U(NA) generally < 0.01 to 7 mg kg(-1)). In this transition zone, acidic (pH < 4) U-enriched ground water (U of 38 mg L(-1)) has weathered away calcite veins resulting in greater porosity, higher hydraulic conductivity, and higher U contamination (U(NA) 106 to 745 mg kg(-1)) of the weathered interbedded shale and sandstone. These characteristics of the transition zone produce an interval with a high flux of contaminants that could be targeted for remediation.


Subject(s)
Environmental Monitoring , Geologic Sediments/analysis , Uranium/analysis , Water Pollutants, Radioactive/analysis , Environmental Monitoring/methods , Environmental Restoration and Remediation/methods , Fresh Water/analysis , Fresh Water/chemistry , Geologic Sediments/chemistry , Hydrogen-Ion Concentration , Tennessee , Uranium/chemistry , Water Pollutants, Radioactive/chemistry
5.
J Nanosci Nanotechnol ; 6(11): 3517-20, 2006 Nov.
Article in English | MEDLINE | ID: mdl-17252802

ABSTRACT

We have developed a novel microbial process that exploits the ability of Fe(III)-reducing microorganisms to produce copious amounts of extracellular magentites and metal-substituted magnetite nanoparticles. The Fe(III)-reducing bacteria (Theroanaerobacter ethanolicus and Shewanella sp.) have the ability to reduce Fe(III) and various metals in aqueous media and form various sized magnetite and metal-substituted magnetite nano-crystals. The Fe(III)-reducing bacteria formed metalsubstituted magnetites using iron oxide plus metals (e.g., Co, Cr, Mn, Ni) under conditions of relatively low temperature (<70 degrees C), ambient pressure, and pH values near neutral to slightly basic (pH = 6.5 to 9). Precise biological control over activation and regulation of the biosolid-state processes can produce magnetite particles of well-defined size (typically tens of nanometers) and crystallographic morphology, containing selected dopant metals into the magnetite (Fe(3-y)XyO4) structure (where X = Co, Cr, Mn, Ni). Magnetite yields of up to 20 g/L per day have been observed in 20-L vessels. Water-based ferrofluids were formed with the nanometer sized, magnetite, and metal-substituted biomagnetite particles.


Subject(s)
Ferrosoferric Oxide/chemical synthesis , Metal Nanoparticles/chemistry , Bacteria/metabolism , Ferric Compounds/chemistry , Ferrosoferric Oxide/chemistry , Hydrogen-Ion Concentration , Iron/chemistry , Microscopy, Electron, Transmission , Nanoparticles/chemistry , Shewanella/metabolism , Temperature , X-Ray Diffraction
6.
Biotechnol Bioeng ; 75(6): 718-24, 2001 Dec 20.
Article in English | MEDLINE | ID: mdl-11745150

ABSTRACT

Enterokinase and recombinant enterokinase light chain (rEK(L)) have been used widely to cleave fusion proteins with the target sequence of (Asp)(4)-Lys. In this work, we show that their utility as a site-specific cleavage agent is compromised by sporadic cleavage at other sites, albeit at low levels. Further degradation of the fusion protein in cleavage reaction is due to an intrinsic broad specificity of the enzyme rather than to the presence of contaminating proteases. To offer facilitated purification from fermentation broth and efficient removal of rEK(L) after cleavage reaction, thus minimizing unwanted cleavage of target protein, histidine affinity tag was introduced into rEK(L). Utilizing the secretion enhancer peptide derived from the human interleukin 1 beta, the recombinant EK(L) was expressed in Saccharomyces cerevisiae and efficiently secreted into culture medium. The C-terminal His-tagged EK(L) was purified in a single-step procedure on nickel affinity chromatography. It retained full enzymatic activity similar to that of EK(L), whereas the N-terminal His-tagged EK(L) was neither efficiently purified nor had any enzymatic activity. After cleavage reaction of fusion protein, the C-terminal His-tagged EK(L) was efficiently removed from the reaction mixture by a single passage through nickel-NTA spin column. The simple affinity tag renders rEK(L) extremely useful for purification, post-cleavage removal, recovery, and recycling and will broaden the utility and the versatility of the enterokinase for the production of recombinant proteins.


Subject(s)
Enteropeptidase/genetics , Recombinant Fusion Proteins/genetics , Saccharomyces cerevisiae/genetics , Affinity Labels , Base Sequence , Chromatography, Affinity , DNA Primers , Electrophoresis, Polyacrylamide Gel , Enteropeptidase/biosynthesis , Enteropeptidase/isolation & purification , Hydrolysis , Recombinant Fusion Proteins/biosynthesis , Recombinant Fusion Proteins/isolation & purification
7.
Pharmacol Biochem Behav ; 65(1): 191-8, 2000 Jan 01.
Article in English | MEDLINE | ID: mdl-10638653

ABSTRACT

Vaccination of animals to elicit drug-specific antibodies, or the passive transfer of such antibodies from other animals, can reduce the behavioral effects of drugs such as cocaine and heroin. To study the potential application of this approach to treating nicotine dependence, IgG was isolated from rabbits immunized with a nicotine-protein conjugate vaccine. Anesthetized rats received immune IgG containing nicotine-specific antibodies (Nic-IgG) or control-IgG i.v.. Thirty minutes later, rats received nicotine at 0.03 mg/kg i.v., equivalent on an mg/kg basis to the nicotine intake from two cigarettes by a smoker. Compared to control-IgG, Nic-IgG reduced the brain nicotine concentration in a dose-related manner (65% reduction at the highest IgG dose). Pretreatment with Nic-IgG also reduced the distribution to brain of five repeated doses of nicotine (equivalent to the nicotine intake from 10 cigarettes) administered over 80 min. To study blood pressure effects, rats received control-IgG or Nic-IgG 1 day prior to administering nicotine. Nicotine-induced systolic blood pressure increases were attenuated by Nic-IgG in a dose-related manner, and were almost completely blocked by the highest Nic-IgG dose. Pretreatment with Nic-IgG also completely prevented the nicotine-induced stimulation of locomotor activity observed in rats receiving control-IgG. Nic-IgG did not prevent locomotor activation from cocaine, demonstrating its specificity for nicotine. These data demonstrate that the administration of nicotine-specific antibodies can reduce or prevent some of the pharmacokinetic, cardiovascular, and behavioral consequences of nicotine in rats. Effects were observed at nicotine doses and nicotine serum concentrations equal to or exceeding those typically associated with nicotine exposure in cigarette smokers. A potential role for immunization in the treatment of nicotine dependence is suggested.


Subject(s)
Brain/metabolism , Nicotine/immunology , Vaccines, Conjugate/immunology , Animals , Blood Pressure/drug effects , Immunization, Passive , Immunoglobulin G/immunology , Motor Activity/drug effects , Nicotine/pharmacokinetics , Nicotine/pharmacology , Rabbits , Rats , Rats, Sprague-Dawley , Vaccination
8.
Biotechnol Prog ; 15(5): 884-90, 1999.
Article in English | MEDLINE | ID: mdl-10514258

ABSTRACT

An N-terminus sequence of human interleukin 1beta (hIL-1beta) was used as a fusion expression partner for the production of two recombinant therapeutic proteins, human granulocyte-colony stimulating factor (hG-CSF) and human growth hormone (hGH), using Saccharomyces cerevisiae as a host. The expression cassette comprised the leader sequence of killer toxin of Kluyveromyces lactis, the N-terminus 24 amino acids (Ser5-Ala28) of mature hIL-1beta, the KEX2 dibasic endopeptidase cleavage site, and the target protein (hG-CSF or hGH). The gene expression was controlled by the inducible UAS(gal)/MF-alpha1 promoter. With the expression vector above, both recombinant proteins were well secreted into culture medium with high secretion efficiencies, and especially, the recombinant hGH was accumulated up to around 1.3 g/L in the culture broth. This is due presumably to the significant role of fused hIL-1beta as secretion enhancer in the yeast secretory pathway. In our recent report, various immunoblotting analyses have shown that the presence of a core N-glycosylation resident in the hIL-1beta fragment is likely to be of crucial importance in the high-level secretion of hG-CSF from the recombinant S. cerevisiae. When the N-glycosylation was completely blocked with the addition of tunicamycin to the culture, the secretion of hG-CSF and hGH was decreased to a negligible level although the other host-derived proteins were well secreted to the culture broth regardless of the presence of tunicamycin. The N-terminal sequencing of the purified hG-CSF verified that the hIL-1beta fusion peptide was correctly removed by in vivo KEX2 protease upon the exit of fusion protein from Golgi complex. From the results presented in this article, it is strongly suggested that the N-terminus fusion of the hIL-1beta peptide could be utilized as a potent secretion enhancer in the expression systems designed for the secretory production of other heterologous proteins from S. cerevisiae.


Subject(s)
Interleukin-1/biosynthesis , Interleukin-1/metabolism , Recombinant Fusion Proteins/biosynthesis , Recombinant Fusion Proteins/metabolism , Saccharomyces cerevisiae/genetics , Enteropeptidase/biosynthesis , Enteropeptidase/genetics , Enteropeptidase/isolation & purification , Enteropeptidase/metabolism , Genetic Vectors/biosynthesis , Granulocyte Colony-Stimulating Factor/biosynthesis , Granulocyte Colony-Stimulating Factor/genetics , Granulocyte Colony-Stimulating Factor/isolation & purification , Granulocyte Colony-Stimulating Factor/metabolism , Human Growth Hormone/biosynthesis , Human Growth Hormone/genetics , Human Growth Hormone/isolation & purification , Human Growth Hormone/metabolism , Humans , Interleukin-1/genetics , Recombinant Fusion Proteins/genetics
9.
Int J Oral Maxillofac Implants ; 12(2): 252-8, 1997.
Article in English | MEDLINE | ID: mdl-9109277

ABSTRACT

This report presents the case of a teenager affected by hypohidrotic ectodermal dysplasia and rehabilitated with a fixed maxillary partial prosthesis and mandibular overdenture supported by osseointegrated implants. Treatment had a major impact on patient's self-esteem, function, and esthetics.


Subject(s)
Anodontia/rehabilitation , Dental Implantation, Endosseous , Dental Implants , Ectodermal Dysplasia/rehabilitation , Adolescent , Dental Prosthesis, Implant-Supported , Denture, Complete, Lower , Denture, Overlay , Denture, Partial, Fixed , Ectodermal Dysplasia/genetics , Esthetics, Dental , Humans , Incisor/abnormalities , Male , Mandible/surgery , Maxilla/surgery , Osseointegration , Patient Satisfaction , Self Concept
10.
Photosynth Res ; 7(3): 269-79, 1986 Jan.
Article in English | MEDLINE | ID: mdl-24443123

ABSTRACT

Computer programs written in BASICA (IBM'S VERSION OF BASIC) language were developed for the calculation of the gas exchange parameters of CO2 assimilation, leaf conductance, stomatal conductance, residual conductance, intercellular CO2 concentration, transpiration, water use efficiency and transpiration ratio in an open system. Formulas are discussed in both an algebraic and in a BASIC computer program form. Calculations based on mole fractions of CO2 and water vapor are explained and both molar and mass fluxes are included in the program output to facilitate comparisons with data from the literature. Corrections are made in the program to account for under-estimation of CO2 assimilation due to the increase in flow rates out of sample chambers caused by simultaneous transpiration. A sample output is included to illustrate the formatting capability of the program.

SELECTION OF CITATIONS
SEARCH DETAIL
...