Publications by authors named "Chris Matthews"

4 Publications

  • Page 1 of 1

Comparison of histologic methods for the detection of spores in the gills of Atlantic salmon.

J Vet Diagn Invest 2020 Jan 18;32(1):142-146. Epub 2019 Nov 18.

Moredun Research Institute, Pentlands Science Park, Scotland, UK (Herrero, Dagleish, Thompson).

is a microsporidian associated with gill disease in farmed Atlantic salmon (). Detection of the parasite in histologic tissue sections is challenging using common histochemical stains given that the small, widely distributed parasite spores typically occur individually or in small clusters. We compared the ability of 4 histologic methods to detect spores in serial sections of Atlantic salmon gill tissue: hematoxylin and eosin (H&E), Gram-Twort (GT), calcofluor white (CW), and immunohistochemistry (IHC). Using CW as a benchmark to calculate a relative ratio, IHC consistently detected more spores than CW (median: 1.3), followed by GT (median: 0.2) and H&E (median: 0.1). IHC detected significantly more spores than GT ( < 0.05) and H&E ( < 0.05), and GT more than H&E ( < 0.05). We found significant underestimation of numbers of microsporidia spores in gill disease in Atlantic salmon using conventional histochemical stains and recommend the use of CW or IHC to detect the parasite in tissue sections.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1177/1040638719887707DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7003232PMC
January 2020

A naturally occurring Vif mutant (I107T) attenuates anti-APOBEC3G activity and HIV-1 replication.

J Mol Biol 2013 Aug 23;425(16):2840-52. Epub 2013 May 23.

Laboratory of Molecular Human Retrovirology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada.

The human immunodeficiency virus type 1 (HIV-1) Vif protein counteracts the antiviral activity of the apolipoprotein B mRNA editing enzyme catalytic polypeptide-like 3 (APOBEC3) family of proteins by targeting the proteins for degradation through the ubiquitin-proteasome pathway. Previous mutagenic studies have shown that multiple domains of Vif are required for interacting with APOBEC3G proteins and the proteasome pathway. However, very few mutagenesis and functional analyses of patient-derived Vif proteins have been conducted. In this study, we amplified and cloned the HIV-1 vif genes from the peripheral blood mononuclear cells (PBMCs) of five HIV-1-infected individuals in Nairobi and further tested the impact of the genes on anti-A3G activity and HIV-1 replication. The gene sequence analysis revealed high genetic variation of vif genes from different HIV-1-infected individuals. Interestingly, the Vif proteins derived from two of the three long-term survivors (LTSs) displayed a significantly impaired ability to mediate the degradation of A3G. In particular, a single amino acid change (I107T) in one of the non-functional LTS Vif variants, which has not been previously identified in the Los Alamos databases of vif sequences, was found to be responsible for the lack of anti-A3G activity. Further study demonstrated that HIV-1 carrying an I107T Vif mutation displayed significantly reduced fitness in A3G(+) T cells and PBMCs. Moreover, co-infecting A3G(+) T cells with both the wild-type and I107T Vif viruses resulted in decreased viral replication. Overall, the results of this study indicate that the HIV-1 Vif residue I107 is important for its anti-APOBEC3G activity and viral replication, which may have implications for viral fitness in vivo.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jmb.2013.05.015DOI Listing
August 2013

PET-guided breast biopsy.

Breast J 2011 Mar-Apr;17(2):143-51. Epub 2011 Jan 31.

Naviscan Inc., San Diego, California, USA.

Molecular imaging, using positron emission tomography (PET), has become an integral step in the evaluation of many patients with malignancy. However, its use in patients with breast cancer has been limited by the lower levels of (18) F-fluorodeoxyglucose (FDG) uptake in some breast malignancies compared to other cancers, the small size of many breast cancers, and the need for biopsy under PET guidance. High-resolution breast PET, or positron emission mammography (PEM), with biopsy guidance software, now addresses these issues. We report a prospective, multicenter study designed to test the efficacy and safety of PEM biopsy guidance software in women with FDG-avid breast lesions worrisome for malignancy. The intervention chosen was vacuum-assisted core biopsy. Nineteen subjects underwent a total of 24 PEM-guided biopsies. All lesions were successfully targeted and sampled as determined by post-biopsy image scan evaluation, specimen imaging, and pathologic concordance. Invasive cancer was identified in 13 of 24 lesions (54%), while four (17%) were high-risk lesions and three of these were upgraded to malignancy at excision. No serious adverse events occurred and all patients found the procedure to cause only minimal to mild discomfort. High-resolution PEM-guided breast biopsy is both safe and effective for the sampling of PET-depicted breast lesions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/j.1524-4741.2010.01044.xDOI Listing
July 2011

Aussie rural general practitioner's Arabian sojourn.

Authors:
Chris Matthews

Aust J Rural Health 2004 Dec;12(6):281

Cessnock Uni-clinic, Cessnock, Australia.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/j.1440-1854.2004.00619.xDOI Listing
December 2004