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1.  Evaluation of white matter myelin water fraction in chronic stroke☆ 
NeuroImage : Clinical  2013;2:569-580.
Multi-component T2 relaxation imaging (MCRI) provides specific in vivo measurement of myelin water content and tissue water environments through myelin water fraction (MWF), intra/extra-cellular water fraction (I/EWF) and intra/extracellular and global geometric mean T2 (GMT2) times. Quantitative MCRI assessment of tissue water environments has provided new insights into the progression and underlying white matter pathology in neural disorders such as multiple sclerosis. It has not previously been applied to investigate changes in white matter in the stroke-affected brain. Thus, the purposes of this study were to 1) use MCRI to index myelin water content and tissue water environments in the brain after stroke 2) evaluate relationships between MWF and diffusion behavior indexed by diffusion tensor imaging-based metrics and 3) examine the relationship between white matter status (MWF and fractional anisotropy) and motor behavior in the chronic phase of stroke recovery. Twenty individuals with ischemic stroke and 12 matched healthy controls participated. Excellent to good test/re-test and inter-rater reliability was observed for region of interest-based voxelwise MWF data. Reduced MWF was observed in whole-cerebrum white matter (p < 0.001) and in the ipsilesional (p = 0.017) and contralesional (p = 0.037) posterior limb of internal capsule (PLIC) after stroke compared to whole-cerebrum and bilateral PLIC MWF in healthy controls. The stroke group also demonstrated increased I/EWF, I/E GMT2 and global GMT2 times for whole-cerebrum white matter. Measures of diffusion behavior were also significantly different in the stroke group across each region investigated (p < 0.001). MWF was not significantly correlated with specific tensor-based measures of diffusion in the PLIC for either group. Fractional anisotropy in the ipsilesional PLIC correlated with motor behavior in chronic stroke. These results provide novel insights into tissue-specific changes within white matter after stroke that may have important applications for the understanding of the neuropathology of stroke.
•Changes in structural properties of white matter may occur after stroke.•In vivo magnetic resonance techniques used to quantify brain myelin water fraction.•The imaging approach used showed excellent test/re-test and inter-rater reliability.•Local and global reductions in brain myelin water fraction shown in chronic stroke.•First report of in vivo changes in brain myelin in humans following stroke.
PMCID: PMC3777839  PMID: 24179808
Stroke; Myelin water fraction; T2 relaxation; Motor recovery; White matter
2.  Magnetic resonance spectroscopy biomarkers in premanifest and early Huntington disease 
Neurology  2010;75(19):1702-1710.
To evaluate in vivo brain metabolite differences in control subjects, individuals with premanifest Huntington disease (pre-HD), and individuals with early HD using 1H magnetic resonance spectroscopy (MRS) and to assess their relationship with motor performance.
Eighty-five participants (30 controls, 25 pre-HD, and 30 early HD) were recruited as part of the TRACK-HD study. Eighty-four were scanned at 3 T with single-voxel spectroscopy in the left putamen. Disease burden score was >220 among pre-HD individuals. Subjects underwent TRACK-HD motor assessment including Unified Huntington's Disease Rating Scale (UHDRS) motor scoring and a novel quantitative motor battery. Statistical analyses included linear regression and one-way analysis of variance.
Total N-acetylaspartate (tNAA), a neuronal integrity marker, was lower in early HD (∼15%) vs controls (p < 0.001). N-acetylaspartate (NAA), a constituent of tNAA, was lower in pre-HD (∼8%) and early HD (∼17%) vs controls (p < 0.05). The glial cell marker, myo-inositol (mI), was 50% higher in early HD vs pre-HD (p < 0.01). In early HD, mI correlated with UHDRS motor score (R 2 = 0.23, p < 0.05). Across pre-HD and early HD, tNAA correlated with performance on a tongue pressure task (R 2 = 0.30, p < 0.0001) and with disease burden score (R 2 = 0.17, p < 0.005).
We demonstrate lower putaminal tNAA in early HD compared to controls in a cross-section of subjects. A novel biomarker role for mI in early HD was also identified. These findings resolve disagreement in the literature about the role of MRS as an HD biomarker. We conclude that putaminal MRS measurements of NAA and mI are promising potential biomarkers of HD onset and progression.
= Alzheimer disease;
= creatine;
= disease burden score;
= glutamate;
= glycerophosphocholine;
= Huntington disease;
= myo-inositol;
= magnetic resonance;
= 1H magnetic resonance spectroscopy;
= N-acetylaspartate;
= N-acetylaspartylglutamate;
= phosphocholine;
= phosphocreatine;
= premanifest Huntington disease;
= signal-to-noise ratio;
= total choline;
= total creatine;
= echo time;
= total N-acetylaspartate;
= repetition time;
= University of British Columbia;
= Unified Huntington's Disease Rating Scale;
= voxel-based morphometry.
PMCID: PMC3033605  PMID: 21060093
3.  P73-S High-Resolution Mass Spectrometry Study of the Effects of Chemical and Environmental Stimuli on the Post-Translational State of Histone H4 
As altered epigenetic regulation is a common feature of cancer, a greater understanding is required of the role of histone post-translational modifications as epigenetic regulators of changes in chromatin structure. Chromatin remodeling may also be important in the cellular response to DNA damage induced by anti-cancer drugs. A greater understanding of the nature of histone PTMs and resulting DNA damage in normal and cancerous tissues might indicate differences in the activity of enzymes involved in modifying histones, which could yield potential targets for cancer-specific therapy. Trichostatin A (TSA), a histone deacetylase inhibitor, promotes acetylation of histones and subsequently increases the accessibility to cellular machinery by the unraveling of DNA.
Using high-resolution 9.4T and 12T Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometers, the aim of this work was to characterise, in an unbiased fashion, the histone PTMs induced in histone H4 in response to treatment with TSA and certain environmental stimuli.
FT-ICR mass spectrometry is not well suited to online analysis, owing to the extended scan time required to achieve optimum resolving power. The TriVersa Nanomate enables fraction collection of the HPLC eluent allowing FT acquisition time to be decoupled from separation time. Following further sample cleanup, it proved possible to infuse unfractionated complex histone samples. The most abundant classes of histone present in the cell (H2A, H2B, H3, H4) were observed
The resolving power of FT-ICR permits the post-translational modification of H4 to be observed directly. It can be seen that in the case of cells treated with TSA, there was considerable variation in the acetylation state of histone H4. It was also possible to affect the acetylation state using certain environmental stimuli.
PMCID: PMC2291944
4.  Evaluating large scale health information systems: from practice towards theory. 
With the introduction of large scale health information systems which are incrementally developed from legacy systems, evaluators are faced with difficult methodological and practical problems. Some of the problems involved in multidisciplinary multi-method evaluations care discussed. It is argued that the development of a framework for evaluation is necessary in order to successfully plan an evaluation, understand the implications of the results and make future predictions based upon them. Some suggestions for arriving at such a framework are put forward.
PMCID: PMC2233564  PMID: 9357600
5.  Affinity of the C9 molecule for the C5b-8 complex compared with that for the complex containing C9 molecules. 
Infection and Immunity  1994;62(7):2800-2805.
Gram-negative bacterial cells exposed to a complement source may carry membrane attack complexes containing variable numbers of C9 molecules per C5b-8 site. In order to investigate the assembly of this complex, the ability of C9 molecules to bind to C5b-8 complexes was compared with the binding characteristics of C9 for C5b-8 complexes containing variable numbers of bound C9 molecules. The apparent dissociation constant (Kd) of the C9 molecule for the C5b-8 site on a complement-sensitive strain of Escherichia coli was 1.2 (+/- 0.15) nM at 0 degree C. These conditions allow the binding of one C9 molecule per C5b-8 site. The C5b-8 site containing one C9 molecule bound a second C9 molecule at 0 degree C only after incubation at 37 degrees C. The binding of C9 to a C5b-8 site containing one C9 molecule was found to be 1.3 (+/- 0.2) nM. Therefore, the presence of a C9 molecule did not significantly alter the binding capacity of the C5b-8 site for additional C9 molecules. A similar result was obtained by using rabbit erythrocytes bearing either C5b-8 sites or C5b-8 sites containing one molecule of C9 per complex at 0 degree C. The similarity of binding characteristics for the first and second C9 molecules argues that the initial C9 molecule in the complex does not affect the binding of subsequent C9 molecules. This suggests that a unique C9 binding site that does not involve previously bound C9 molecules may exist on the forming membrane attack complex.
PMCID: PMC302884  PMID: 8005670
6.  A vitreoretinal service. 
BMJ : British Medical Journal  1989;299(6693):241-245.
Many serious disorders that threaten eyesight can now be treated with vitreoretinal surgery. As there was no regional facility for this treatment a service was developed to provide it. Among the first 100 patients treated over half had diabetic vitreoretinal disease. The remainder had ocular trauma (15), non-diabetic vasculopathy (10), rhegmatogenous retinal detachment (10), and miscellaneous disorders including diagnostic procedures (14). Sight was improved in most cases, 27 diabetic and 21 non-diabetic patients regaining navigating vision. Few patients were made worse: one only of the 49 non-diabetic patients and 12 of the 51 diabetic patients, and none whose vision was better than the ability to count fingers before operation. The many indications for this procedure, the size of the population that could benefit (an estimated minimum of 3800 operations per year in the United Kingdom in patients with diabetes alone), and the great potential benefit of the procedure all suggest the need for regional services. These would be cost effective in preventing blindness.
PMCID: PMC1836906  PMID: 2504382
7.  Template-directed arrest of mammalian mitochondrial DNA synthesis. 
Molecular and Cellular Biology  1986;6(4):1261-1267.
Mammalian mitochondrial DNA often contains a short DNA displacement loop at the heavy-strand origin of replication. This short nascent DNA molecule has been used to study site-specific termination of mitochondrial DNA synthesis in human and mouse cells. We examined D-loop strand termination in two distantly related artiodactyls, the pig and the cow. Porcine mitochondrial DNA was unique among mammals in that it contained only a single species of D-loop single-stranded DNA. Its 3' end mapped to a site 187 nucleotides from the 5' end of the proline tRNA gene. This site was 21 and 47 nucleotides 5' to two very similar sequences (5' ACATATPyATTAT 3') which are closely related to the human and mouse termination-associated sequences noted by Doda et al. (J. N. Doda, D. T. Wright, and D. A. Clayton, Proc. Nat. Acad. Sci. USA 78:616-6120, 1981). Bovine mitochondrial DNA contained three major D-loop DNA species whose 3' ends mapped to three different sites. These sites were not found in the porcine sequence. However, the bovine termination sites were located 60 to 64 base pairs 5' from sequences which were also very similar to the termination-associated sequences present in pigs and other mammals. These results firmly establish the concept that arrest of heavy-strand DNA synthesis is an event determined, at least in part, by template sequence. They also suggest that arrest is determined by sequences which are a considerable physical distance away from the actual termination site.
PMCID: PMC367638  PMID: 3785163
8.  A Study of Drug Residues in Milk Following Intrauterine Infusion of Antibacterial Drugs in Lactating Cows 
The Canadian Veterinary Journal  1979;20(12):354-357.
Intrauterine infusion of nine antibacterial compounds caused detectable drug residues in 17 out of 165 cows or in 25 out of 1110 posttreatment milkings. Four cows treated with pyrolidinomethyl tetracycline suspension had drug residues at the first milking. One cow had residues after oxytetracycline treatment, two after procaine penicillin G, three after acriflavin and after chloramphenicol-dapsone and four after hibitane. Nitrofurazone, nitrofurathiazide and Hibitane Compound® did not cause detectable inhibitory residues in any milk sample.
PMCID: PMC1789638  PMID: 534992
9.  Bovine Granular Vulvitis Associated with Ureaplasma Infection 
A granular vulvitis syndrome associated with ureaplasma infection was first recognized in Ontario dairy herds in 1972.
The acute form of the disease was characterized by a purulent vulvar discharge, an inflamed hyperemic vulvar mucosa and varying degrees of granularity. In the chronic form, there was an absence of a purulent discharge and a gradual decline in the severity of the hyperemia and granularity. Epithelial inclusion cysts were observed in the vulvar epithelium of approximately 10% of affected cows.
A seasonal variation in the incidence of the disease was observed. Herd morbidities during the summer months reached a low of 37% and increased to 75% during the winter months with constant housing.
When widespread in herds, the acute form of the disease had a significant effect on fertility. In four herds examined, first service conceptions dropped on average by 27%.
The chronic form of the disease had a less detrimental effect on fertility with first service conceptions being reduced on average by 13%.
Intrauterine infusions of a tetracycline 24 hours postbreeding were found to be of value in improving conception rates in acutely affected herds.
PMCID: PMC1789526  PMID: 427710
10.  Isolation of Ureaplasma from bovine granular vulvitis. 
Cultures for mycoplasmatales, viruses and bacteria were made from bovine vulvar swabs to determine whether ureaplasma was associated with a clinical granular vulvitis observed in 16 Ontario dairy herds. Ureaplasma was isolated from 23.5% of 34 clinically normal cows, 74% of 27 cows with mild to moderate vulvar hyperemia but no discharge and 100% of 20 cows with acute vulvar hyperemia accompanied by purulent discharge. There were statistically significant differences in rates of isolation among clinical groups. Mycoplasma bovigenitalium was isolated from 7.7% and 20% of cows with moderate or acute vulvitis respectively but not from normal cows. Haemophilus somnus was isolated from 25% of cows with acute vulvitis. There were no significant differences in isolations of Escherichia coli, Corynebacterium pyogenes and alpha-hemolytic streptococcus between normal and clinically affected animals. Cultures of 135 repeat samples from 33 cows revealed that ureaplasma persisted in some animals for at least three months. No viruses were isolated from any of the animals in this study.
PMCID: PMC1277608  PMID: 352491
Compensatory hypertrophy of the kidney in albino rats becomes less as age advances. There is a rapid decrease from 5 days to 60 days of age and then a slow diminution throughout adult life.
PMCID: PMC2132169  PMID: 19870064

Results 1-11 (11)