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Biomedical subjects

C Beaulieu

Publications and source records attributed to C Beaulieu.

At least 19 recordsLinked to original sources
PubMed2007

Use of magnetic resonance imaging to measure facial soft tissue depth.

OBJECTIVE: To investigate the feasibility of using magnetic resonance imaging to estimate facial tissue depth at standard anthropological facial landmarks. DESIGN: Standard facial landmarks were marked with magnetic resonance imaging opaque markers on 10 normal subjects. Three observers estimated facial tissue depth at these landmarks on up to three separate occasions, and comparisons were made among the observers. SETTING: The study was conducted with volunteers at the University of Alberta Biomechanical Engineering unit. PARTICIPANTS: The volunteers were healthy individuals of both sexes between the ages of 18 and 30 years. MAIN OUTCOME MEASURES: The technical error of measurement among observers was used as the main indicator of precision of measurement. RESULTS: Measurements of tissue depth showed tolerable technical error of measurement and were precisely measured within and among observers. CONCLUSIONS: Magnetic resonance images can be used to estimate tissue depth in human faces with precision.

Adolescent↗
PubMed2006

Monitoring the microbial populations and temperatures of fresh broccoli from harvest to retail display.

Microbial populations and the temperature of fresh broccoli were monitored at several steps of a supply chain by sampling 33 distinct lots of locally grown produce over two seasons during harvest, storage, wholesale handling, and retail display. Imported broccoli was also sampled, but only at retail display. Microbiological analyses were conducted on the florets of 201 local and 60 imported broccoli samples to determine populations of total aerobic bacteria (aerobic colony count), fecal coliforms, Escherichia coli, and Listeria monocytogenes. All the samples had mean aerobic colony counts ranging between 4 and 6 log CFU/g, but L. monocytogenes was not detected (limit of detection =100 CFU/g). Fecal coliforms and E. coli (limit of detection =20 most probable number per 100 g) were found in 22 of 126 samples of local broccoli collected at various steps of the production and distribution system during the first season. None was found in 75 samples collected in the second season. Fecal coliforms and E. coli were found in 2 of 60 imported broccoli samples. Broccoli temperatures were relatively well controlled throughout the production and distribution system. No clear change in produce microbial populations was evident between harvest and retail display, during both sampling seasons. However, a large experimental variability was found, possibly associated with the high variability of the initial levels of microbial populations on broccoli at harvest.

Bacteria, Aerobic↗
PubMed2003

Multilocal magnetic resonance perfusion mapping comparing the cerebral hemodynamic effects of decompressive craniectomy versus reperfusion in experimental acute hemispheric stroke in rats.

This study examined the hemodynamic effects of craniectomy compared to reperfusion on the temporal evolution of cerebral perfusion in different brain regions in a rat model of focal cerebral ischemia. Three groups were investigated: no treatment, reperfusion or craniectomy at 1 h. Perfusion-weighted magnetic resonance imaging (PWI) was performed serially from 0.5 to 6 h. Relative regional cerebral blood flow was calculated for different regions and infarct volume was assessed by histology at 24 h. As conclusion, both, craniectomy and reperfusion increased cerebral perfusion in the acute phase of cerebral ischemia. While reperfusion resulted in a homogeneous improvement of perfusion in the cortex and basal ganglia, craniectomy improved only cortical perfusion in areas directly under the craniectomy site. PWI is well suited to non-invasively monitor perfusion alterations after aggressive therapeutical approaches in stroke.

Acute Disease↗
PubMed2003

Antagonistic properties of two recombinant strains of Streptomyces melanosporofaciens obtained by intraspecific protoplast fusion.

Intraspecific protoplast fusion was used to produce stable prototrophic recombinants of Streptomyces melanosporofaciens EF-76, a biocontrol agent of plant disease producing geldanamycin. Two recombinant strains (FP-54 and FP-60) that differed with regard to their antagonistic properties against Bacillus cereus ATCC 14579, Streptomyces scabies EF-35 and Phytophthora fragariae var. rubi 390 were characterized. FP-60 lost the ability to inhibit the in vitro growth of these microbial strains while FP-54 exhibited higher antagonistic activities against them. FP-60 was deficient in geldanamycin biosynthesis whereas FP-54 was shown to produce, in addition to geldanamycin, at least two other antimicrobial compounds that were absent in the culture supernatants of strain EF-76. Like the wild-type strain EF-76, strain FP-54 reduced common scab symptoms on potato tuber but no significant difference was observed between the disease index attributed to tubers treated with strain EF-76 or with strain FP-54. Strain FP-60 showed no protective effect against common scab. The disease index of tubers treated with this recombinant was worse than the index associated with potato tubers from control treatments.

Anti-Bacterial Agents↗
PubMed2003

Identification of Streptomyces coelicolor proteins that are differentially expressed in the presence of plant material.

Streptomyces coelicolor and Lemna minor were used as a model to study the modulation of bacterial gene expression during plant-streptomycete interactions. S. coelicolor was grown in minimal medium with and without L. minor fronds. Bacterial proteomes were analyzed by two-dimensional gel electrophoresis, and a comparison of the two culture conditions resulted in identification of 31 proteins that were induced or repressed by the presence of plant material. One-half of these proteins were identified by peptide mass fingerprinting by using matrix-assisted laser desorption ionization-time of flight mass spectrometry. The induced proteins were involved in energetic metabolism (glycolysis, pentose phosphate pathway, oxidative phosphorylation), protein synthesis, degradation of amino acids, alkenes, or cellulose, tellurite resistance, and growth under general physiological or oxidative stress conditions. The repressed proteins were proteins synthesized under starvation stress conditions. These results suggest that root exudates provide additional carbon sources to the bacteria and that physiological adaptations are required for efficient bacterial growth in the presence of plants.

Araceae↗
PubMed2002

Photodegradation of RDX in aqueous solution: a mechanistic probe for biodegradation with Rhodococcus sp.

Recently we demonstrated that Rhodococcus sp. strain DN22 degraded hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) (1) aerobically via initial denitration followed by ring cleavage. Using UL 14C-[RDX] and ring labeled 15N-[RDX] approximately 30% of the energetic chemical mineralized (one C atom) and 64% converted to a dead end product that was tentatively identified as 4-nitro-2,4-diaza-butanal (OHCHNCH2NHNO2). To have further insight into the role of initial denitration on RDX decomposition, we photolyzed the energetic chemical at 350 nm and pH 5.5 and monitored the reaction using a combination of analytical techniques. GC/ MS-PCI showed a product with a [M+H] at 176 Da matching a molecular formula of C3H5N5O4 that was tentatively identified as the initially denitrated RDX product pentahydro-3,5-dinitro-1,3,5-triazacyclohex-1-ene (II). LC/MS (ES-) showed that the removal of RDX was accompanied by the formation of two other key products, each showing the same [M-H] at 192 Da matching a molecular formula of C3H7N5O5. The two products were tentatively identified as the carbinol (III) of the enamine (II) and its ring cleavage product O2NNHCH2NNO2CH2NHCHO (IV). Interestingly, the removal of III and IV was accompanied by the formation and accumulation of OHCHNCH2NHNO2 that we detected with strain DN22. At the end of the experiment, which lasted 16 h, we detected the following products HCHO, HCOOH, NH2CHO, N2O, NO2-, and NO3-. Most were also detected during RDX incubation with strain DN22. Finally, we were unable to detect any of RDX nitroso products during both photolysis and incubation with the aerobic bacteria, emphasizing that initial denitration in both cases was responsible for ring cleavage and subsequent decomposition in water.

Biodegradation, Environmental↗
PubMed2002

Detection of explosives and their degradation products in soil environments.

Polynitro organic explosives [hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) and 2,4,6-trinitrotoluene (TNT)] are typical labile environmental pollutants that can biotransform with soil indigenous microorganisms, photodegrade by sunlight and migrate through subsurface soil to cause groundwater contamination. To be able to determine the type and concentration of explosives and their (bio)transformation products in different soil environments, a comprehensive analytical methodology of sample preparation, separation and detection is thus required. The present paper describes the use of supercritical carbon dioxide (SC-CO2), acetonitrile (MeCN) (US Environmental Protection Agency Method 8330) and solid-phase microextraction (SPME) for the extraction of explosives and their degradation products from various water, soil and plant tissue samples for subsequent analysis by either HPLC-UV, capillary electrophoresis (CE-UV) or GC-MS. Contaminated surface and subsurface soil and groundwater were collected from either a TNT manufacturing facility or an anti-tank firing range. Plant tissue samples were taken fromplants grown in anti-tank firing range soil in a greenhouse experiment. All tested soil and groundwater samples from the former TNT manufacturing plant were found to contain TNT and some of its amino reduced and partially denitrated products. Their concentrations as determined by SPME-GC-MS and LC-UV depended on the location of sampling at the site. In the case of plant tissues, SC-CO2 extraction followed by CE-UV analysis showed only the presence of HMX. The concentrations of HMX (<200 mg/kg) as determined by supercritical fluid extraction (SC-CO2)-CE-UV were comparable to those obtained by MeCN extraction, although the latter technique was found to be more efficient at higher concentrations (>300 mg/kg). Modifiers such as MeCN and water enhanced the SC-CO2 extractability of HMX from plant tissues.

Azocines↗
PubMed2001

Design and synthesis of a novel class of histone deacetylase inhibitors.

Histone deacetylase inhibitors (HDACs) have emerged as a novel class of antiproliferative agents. Utilizing structure-based design, the synthesis of a series of sulfonamide hydroxamic acids is described. Further optimization of this series by substitution of the terminal aromatic ring yielded HDAC inhibitors with good in vitro and in vivo activities.

Cell Division↗
PubMed2001

Comparison of diffusion, blood oxygenation, and blood volume changes during global ischemia in rats.

Rapid diffusion, blood oxygenation, and blood volume weighted echo planar imaging was used to monitor global cerebral ischemia by cardiac arrest in rats. Serial CBV measurements used intravascular iron oxide contrast media (iron dextran). ADC dropped by 5% within 20 sec of cardiac arrest, then continued to decay slowly until a larger rapid drop after 2 min. After iron oxide injection, the initial 5% drop was not observed. The transverse relaxation rate (R(2), R(*)(2) no iron injection) increased rapidly after cardiac arrest, peaking at about 30 sec, then declining towards baseline. The CBV dropped by about 50% within 20 sec. The initial 5% ADC drop may be a vascular artifact. The rapidity of the CBV-weighted signal drop suggests a flow-mediated contribution to the iron oxide contrast mechanism. Magn Reson Med 45:10-16, 2001.

Animals↗
PubMed2001

Relaxation times and microstructures.

A discussion is presented of the evaluation of multiple relaxation components from water protons in biological tissue. The principal focus is to draw attention to the way in which limitations in the raw NMR data, such as signal-to-noise ratio, data sampling density and acquisition window width, affect the precision and resolution in the processed multiple component solution of the return to thermal equilibrium. The second issue discussed is the interpretation of these multiple components in terms of microstructural compartments of the biological sample and, thirdly, we outline some of the successes in determining regional and pathological variations in microstructure in the human body in-vivo, using the technique of multiple relaxation components.

Animals↗
PubMed2001

Purification and properties of a beta-1,6-glucanase from Streptomyces sp. EF-14, an actinomycete antagonistic to Phytophthora spp.

Extracellular enzymes with glucanase activities are an important component of actinomycete-fungus antagonism. Streptomyces sp. EF-14 has been previously identified as one of the most potent antagonists of Phytophthora spp. A beta-1,6-glucanase (EC 3.2.1.75; glucan endo-1,6-beta-glucosidase) was purified by four chromatographic steps from the culture supernatant of strain EF-14 grown on a medium with lyophilized cells of Candida utilis as main nutrient source. The glucanase level in this medium followed a characteristic pattern in which the rise of beta-1,6-glucanase activity always preceded that of beta-1,3-glucanase. The molecular mass of the enzyme was estimated to be 65 kDa and the pI approximately 5.5. It hydrolyzed pustulan by an endo-mechanism generating gentiobiose and glucose as final products. Laminarin was not hydrolyzed indicating that the enzyme does not recognize beta-1,6-links flanked by beta-1,3-links. No significant clearing of yeast cell walls in liquid suspensions or in agar plates was observed indicating that this beta-1,6-glucanase is a non-lytic enzyme. This is the first beta-1,6-glucanase characterized from an actinomycete.

Amino Acid Sequence↗
PubMed2001

Random amplified ribosomal DNA restriction analysis for rapid identification of thermophilic Actinomycete-like bacteria involved in hypersensitivity pneumonitis.

Hypersensitivity pneumonitis (HP) is a pulmonary disease characterised by inflammation that can be caused by, amongst other substances, a subset of 4 thermophilic mycelial bacteria: Saccharopolyspora rectivirgula, Saccharomonospora viridis, Thermoactinomyces sacchari, and Thermoactinomyces vulgaris. Air sampling analyses in highly contaminated environments are often performed to evaluate exposure to these species which are difficult and fastidious to identify by conventional techniques. The aim of this study was to use amplified ribosomal DNA restriction analysis (ARDRA) to develop a method of identification for those thermophilic organisms that would be more rapid and simple. Strains of these 4 species were obtained from the American type culture collection (ATCC) and were characterized using biochemical tests and ARDRA patterns obtained on their partial-lenght amplified 16S rDNAs. To validate this approach, ARDRA with two restriction enzymes, TaqI and HhaI, was applied to 49 thermophilic actinomycete-like strains from environmental samples (sawmills). The results obtained show that combining some cultural characteristics and biochemical tests, such as xanthine or hypoxanthine decomposition, growth in the presence of NaCl, lysozyme or novobiocin, and spore resistance over 100 degrees C provide a rough identification and selection of the genera of interest. Consequently, target species could be confirmed by digestion of partial-lenght 16S rDNA with the use of Taql and HhaI restriction enzymes that gave specific restriction patterns. ARDRA analyses on the 49 environmental actinomycete-like organisms revealed the presence of 8 Saccharopolyspora rectivirgula, 2 Saccharomonospora viridis, and 15 Thermoactinomyces vulgaris strains, the other strains had restriction patterns different than those of the species of interest. Results of the present study will be applicable to other potential HP environments such as dairy barns, peat bogs and compost plants.

Actinomycetales↗
PubMed2001

Taxonomic study on nonpathogenic streptomycetes isolated from common scab lesions on potato tubers.

Numerical analysis was carried out to compare sixteen nonpathogenic actinomycetes isolated from common scab lesions on potato tubers with Streptomyces scabiei type strain as well as with other streptomycete groups. These isolates were divided into two classes according to their level of similarity with S. scabiei. Isolates resembling S. scabiei were associated with S. griseoruber or with S. violaceusniger while isolates exhibiting less than 61% of similarity with S. scabiei were phenotypically related to S. albidoflavus or to S. atroolivaceus. Sequence of the 16S rRNA gene of each isolate was obtained and compared against the GenBank nucleotide database. No significant match could be established between the sequences of two potato isolates and the ones available in the GenBank database. The other isolates were closely related with S. setonii (S. griseus), S. mirabilis, S. fimbriatus, S. violaceoruber, S. melanosporofaciens and S. thermocarboxydus.

DNA, Ribosomal↗
PubMed2001

Decreasing process variation in the care of carotid endarterectomy patients.

Avoidable complications after successful carotid endarterectomy surgery typically occur in the immediate postoperative period; most of these complications are related to hemodynamic instability. At Saint Agnes Medical Center, process variation resulted from 22 anesthesiologists and 11 surgeons doing the same process 242 ways. We introduced a Post-Anesthesia Care Unit Carotid Order Set to standardize the process, drug sequence, and drug choices for postoperative carotid endarterectomy patients. Ongoing monitoring demonstrated that this reduction in process variability resulted in a lower complication rate for stroke and wound hematoma.

Algorithms↗
PubMed2000

Chiral alpha-substituted carbonyls and alcohols from the S(N)2' displacement of cuprates on chiral carbonates: An alternative to the alkylation of chiral enolates

A highly stereoselective sequence of reactions, based on the anti-selective S(N)2' addition of cuprates to allylic carbonates, transforms alkynes or alkenyl halides into carbonyls having alpha-chiral centers. The method, which uses menthone as a chiral auxiliary, is a useful alternative to the alkylation of chiral enolates with the added advantage of allowing for the "alkylation" of sec- and tert-alkyl and aryl groups.

Journal Article↗
PubMed2000

Comparison of diffusion-weighted MRI and CT in acute stroke.

OBJECTIVE: To compare diffusion-weighted MRI (DWI) and CT with respect to accuracy of localizing acute cerebral infarction; sensitivity, specificity, and interrater reliability for identifying more than one-third middle cerebral artery (MCA) territory involvement; and correlation of acute lesion volume with final infarct volume. METHOD: Nineteen consecutive stroke patients underwent CT and DWI within 7 hours of stroke onset and a follow-up DWI examination 36 hours after symptom onset, which served as the "gold standard" for lesion location and extent of MCA involvement. Each scan was evaluated for acute ischemic lesions by two experienced observers. After 30 days, T2-weighted MRI was obtained for assessment of the final infarct volume. RESULTS: The acute CT and DWI scans were obtained on average 2.6 and 5.1 hours after symptom onset. On DWI the acute lesion was identified correctly in all instances and on CT it was identified correctly in 42 to 63% of patients. Sensitivity for detection of more than 33% MCA involvement was better for DWI (57 to 86%) than for CT (14 to 43%), whereas specificity was excellent for both. Interrater reliability was moderately good for both (kappa, 0.6 for DWI; 0.5 for CT). A positive correlation (r = 0.79; p = 0.001) existed between lesion volume on acute DWI and final infarct volume, whereas no correlation was found between CT volume and final infarct volume. CONCLUSION: When compared with CT, DWI was more accurate for identifying acute infarction and more sensitive for detection of more than 33% MCA involvement. In addition, lesion volume on acute DWI, but not on acute CT, correlated strongly with final infarct volume. Additional studies are required to demonstrate whether these advantages of DWI are clinically relevant in the management of patients with acute stroke.

Aged↗
PubMed2000

Spreading waves of transient and prolonged decreases in water diffusion after subarachnoid hemorrhage in rats.

Diffusion-weighted MRI (DWI), which can detect cortical spreading depressions (SDs) as propagating waves of reduced apparent diffusion coefficient (ADC) of water, was used to investigate whether spreading depression occurs after subarachnoid hemorrhage (SAH) induced by endovascular perforation in the rat. Eleven rats underwent SAH while positioned in the magnet. The ADC measurements had a temporal resolution of 12 sec. Transient decreases in ADC to 74 +/- 5% of pre-SAH values were observed in three rats after SAH, which propagated over the cortex with an average speed of 4.2 +/- 0. 6 mm/min, consistent with an SD wave. Furthermore, in all 11 rats, a wavefront of reduced ADC, which did not resolve within the 12 min observation period, spread at a speed of 3.2 +/- 1.7 mm/min in the ipsilateral cortex, and again is consistent with the speed of SD propagation. Therefore, spreading depression-like cellular depolarization is a consequence of acute subarachnoid hemorrhage in rats. Magn Reson Med 44:110-116, 2000.

Animals↗