Search PubMed⌕ Search

Biomedical subjects

A G Wilson

Publications and source records attributed to A G Wilson.

140 records · Page 8Linked to original sources
PubMed1967

Powassan virus: persistence of virus activity during 1966.

Powassan virus isolations were achieved from three of 60 pools of Ixodes cookei ticks removed from 286 groundhogs (Marmota monax) which were collected some 200 miles north of Toronto between May 5 and September 5, 1966. Virus yields per pool of one to 11 ticks ranged from 10(2.5) to 10(6.0) TCD(50) for primary swine kidney tissue cultures, and positive pools were collected on June 24, July 15 and August 10. Powassan neutralizing antibodies were detected by mouse inoculation tests in 143 of 362 animals including 127 of 286 groundhogs, 14 of 45 red squirrels (Tamiasciurus hudsonicus) and two of 31 other forest mammals. The monthly prevalence of antibody in the current season's groundhogs increased from 0 to 25% with the progression of summer, but in older animals the incidence remained between 38 and 62% throughout the season. These results substantiate earlier findings which pointed towards the maintenance of Powassan virus in nature by a cycle involving groundhogs and squirrels as reservoirs, with ticks as vectors, from which human infections occurred tangentially.

Animals↗
PubMed1966

Powassan virus: vernal spread during 1965.

Powassan virus was isolated from seven pools of Ixodes cookei ticks removed from groundhogs (Marmota monax) collected near North Bay, Ontario, between May and August 1965, including five pools obtained during spring. Tick pools, each comprising one to nine ticks, contained 2.0 to 5.5 log(10) TCD(50) of virus upon titration in monolayer cultures of primary swine kidney cells. Powassan virus neutralizing antibody prevalence in sera of the current season's groundhogs increased steadily from zero during May to 25% during August but remained relatively unchanged (42% to 58%) in the previous season's groundhogs, thereby confirming that active infection had occurred particularly amongst juvenile groundhogs mainly during spring 1965. Isolation of one strain of Silverwater virus from Haemaphysalis leporis-palustris ticks and detection of neutralizing antibody in three of nine snowshoe hares (Lepus americanus) confirmed the active spread of this agent during 1965.

Animals↗
PubMedDate not supplied

Intravascular lipoma of the superior vena cava: CT features.

An intrinsic lipoma of the right brachiocephalic vein and superior vena cava is described. This intraluminal tumour expanded the superior vena cava and produced superior mediastinal widening, which was of fatty radiodensity on chest radiography. The CT and venographic findings in this case are described.

Adult↗
PubMedDate not supplied

Fractures on the chest radiograph in detection of alcoholic liver disease.

The presence of fractures seen on routine chest radiography was assessed in patients with liver disease to see whether it might provide a useful marker of alcoholism. Chest radiographs taken at the time of liver biopsy were examined in 149 patients--72 with alcoholic liver disease (32 (44%) cirrhotic) and 77 with various forms of non-alcoholic liver disease (15 (19 . 5%) cirrhotic)--and in 149 controls. Fractures (85 rib, two clavicular) were much more common in patients with alcoholic liver disease (20 subjects; 28%) than in patients with non-alcoholic liver disease (1; 1 . 3%) or controls 10; 6 . 7%). In alcoholic liver disease rib fractures were significantly more likely to be bilateral or multiple (more than two) or both (p less than 0 . 01). Of patients with alcoholic liver disease, those with fractures were significantly older than those without, but there was no difference in sex, social class, the proportion with cirrhosis, or the proportion known to be alcoholic at the time of the radiograph. In liver disease fractures on the chest radiograph diagnosed alcoholism with 95% specificity and 28% sensitivity. These often overlooked or ignored findings in the chest radiograph may have a wider role in the detection of alcoholism.

Adult↗
PubMedDate not supplied

The pathologist and toxicologist in pharmaceutical product discovery.

Significant change is occurring in the drug discovery paradigm; many companies are utilizing dedicated groups from the toxicology/ pathology disciplines to support early stage activities. The goal is to improve the efficiency of the discovery process for selecting a successful clinical candidate. Toxicity can be predicted by leveraging molecular techniques via rapid high-throughput, low-resource in vitro and in vivo test systems. Several important activities help create a platform to support rapid development of a new molecular entity. The proceedings of this symposium provide excellent examples of these applied concepts in pharmaceutical research and development. Leading biopharmaceutical companies recognize that a competitive advantage can be maintained via rapid characterization of animal models, the cellular identification of therapeutic targets, and improved sensitivity of efficacy assessment. The participation of the molecular pathologist in this quest is evolving rapidly, as evidenced by the growing number of pathologists that interact with drug discovery organizations.

Animals↗
PubMedDate not supplied

Lymphadenopathy after GORE-TEX anterior cruciate ligament reconstruction.

The GORE-TEX (W. L. Gore & Associates, Flagstaff, Arizona) graft was used in humans for about 10 years starting in 1982. During that time thousands of these ligaments were inserted. In our hospital, 162 GORE-TEX cruciate reconstructions were performed between 1986 and 1993 using a standard over-the-top technique. Two of these patients developed inguinal lymphadenopathy secondary to GORE-TEX particulate materials from the ipsilateral knee joint. To our knowledge, this is the first paper describing the above-mentioned complication, which was established by histologic examination, including electron microscopy.

Adult↗
PubMedDate not supplied

TNF +489 polymorphism does not contribute to susceptibility to rheumatoid arthritis.

OBJECTIVES: To determine if a tumour necrosis factor (TNF +489) polymorphism is associated with susceptibility to rheumatoid arthritis (RA). METHODS: Two European populations were studied: 217 controls and 238 patients from the north of England and 145 controls and 179 patients from Spain. HLA-DRB1 and TNF +489 markers were typed using polymerase chain reaction based methods. RESULTS: Strong associations were demonstrated with shared epitope (SE) encoding HLA-DRB1 alleles in the English (OR = 2.9 [2.2-3.9]) and Spanish (OR = 2.3 [1.6-3.3]) populations, however no association was found with TNF +489 alleles. Furthermore carriage of TNF +489A was not associated with the presence of radiological erosions, rheumatoid nodules or rheumatoid factor. CONCLUSION: The role of the TNF locus in the genetic background of RA is unclear, however, our data does not support the previous reported association of the TNF +489A allele with RA susceptibility or severity.

Arthritis, Rheumatoid↗
PubMedDate not supplied

A biologically important single nucleotide polymorphism within the toll-like receptor-4 gene is not associated with rheumatoid arthritis.

BACKGROUND: Rheumatoid arthritis (RA) is a heterogeneous condition affecting 1-2% of the population. Genetics account for 30% of disease susceptibility, with one third arising from the Major Histocompatibility Complex. The toll-like receptor 4 (TLR-4) gene which has been mapped to chromosome 9 (9q32-q33) is involved in innate immune recognition with subsequent proinflammatory cytokine release including TNF. A single nucleotide polymorphism (+896A-->G) resulting in the amino acid substitution (Asp299Gly) has been shown to interrupt TLR-4 mediated signalling. OBJECTIVE: We sought to determine if this TLR-4 polymorphism influences susceptibility to rheumatoid arthritis. METHODS: DNA was extracted from 879 healthy controls and 212 rheumatoid arthritis patients recruited from the north of England. Genotyping was performed using a 5' nuclease Taqman allelic discrimination assay. Allele frequencies were compared between the two groups. We also examined whether an association existed in non-carriers of the DRB1 shared epitope alleles. RESULTS: The frequency of the rare allele was 5.9% in the controls and 7% in the patients. Comparison of rare allele carriage between controls and patients revealed no significant difference p = 0.13. This was also the case in shared epitope negative individuals p = 0.92. CONCLUSION: The TLR-4 +896 polymorphism does not appear to influence susceptibility to rheumatoid arthritis.

Adult↗
PubMedDate not supplied

Metabolism of alachlor by rat and mouse liver and nasal turbinate tissues.

The metabolism of alachlor was studied using in vitro incubations with microsomal fractions prepared from liver and nasal turbinates of rats and mice. Specifically, the transformation of alachlor to 3,5-diethylbenzoquinone-4-imine was examined. A key intermediate in this pathway was identified as 2,6-diethylaniline, the formation of which required catalysis by microsomal arylamidases. 2,6-Diethylaniline was oxidized to 4-amino-3,5-diethylphenol and the electrophilic 3,5-diethylbenzoquinone 4-imine. Rat nasal tissue possessed high enzymatic activity which can promote the formation of the reactive quinone imine. Whole body autoradiographic analysis demonstrated localization of radioactivity in the rat nasal tissue following oral administration of alachlor. A methylsulfide metabolite of alachlor was shown to be a precursor to 2,6-diethylaniline. The deposition of radioactivity in the rat nasal tissue was more pronounced following oral administration of the methylsulfide metabolite of alachlor.

Acetamides↗
PubMedDate not supplied

Studies on the persistence of basic amines in the rabbit lung.

We have investigated the time-course of the pulmonary deposition of imipramine (IMIP) following a single iv injection into rabbits. A pool of IMIP and its demethylated metabolites, which exhibited considerable persistence (half-life of decay = 4 hr), was formed in the lung. This pool, now called the slowly effluxable pool (SEP), appears to be synonymous with the noneffluxable pool (NEP), which we have previously shown to be formed with IMIP in the isolated perfused lung (PL). Furthermore, this pool appears to be responsible for the pulmonary persistence of IMIP, inasmuch as 24 hr after an iv injection it contributes greater than 90% of the total lung concentration. Chlorphentermine and methadone formed SEP's in the IPL of comparable size to that formed with IMIP, whereas phentermine formed a considerably smaller SEP. These results suggest that the degree of hydrophobicity of the amine is an important determinant of the size of the SEP formed. This further supported by the lack of an SEP with the relatively polar amines, 5-hydroxytryptamine and amphetamine. The 10-fold difference in the size of the SEP for compounds known to induce pulmonary phospholipidosis (chlorphentermine and IMIP) and known not to induce lipidosis (phentermine and amphetamine) may suggest a possible involvement of the SEP in the onset of phospholipidosis; this possibility is discussed.

Amines↗