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Biomedical subjects

W E Wilson

Publications and source records attributed to W E Wilson.

88 records · Page 5Linked to original sources
PubMed1971

DDT: participation in ultraviolet-detectable, charge-transfer complexation.

The chlorophenyl groups of DDT and several of its metabolites are capable of participating in a charge-transfer interaction with tetracyanoethylene detectable in the ultraviolet region of the spectrum. In addition, during a change of state DDT undergoes ultraviolet spectral alterations that closely resemble those previously claimed to support the hypothesis suggesting charge-transfer interaction between this pesticide and a component of insect nerve tissue. The pesticide DDT possesses structural characteristics that would permit it to participate in several types of molecular association.

1-Propanol↗
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

Interaction of deltorphin with opioid receptors: molecular determinants for affinity and selectivity.

Opioid receptor analyses of deltorphin A (H-Tyr-D-Met-Phe-His-Leu-Met-Asp-NH2) analogues indicated the following: (a) increased negativity differentially affected affinities (Ki) and selectivity (Ki mu/Ki delta); (b) shifted sequence heptapeptides, [Asp5,Leu6,Met-NH2(7)] and [Asp4,His5,Leu6,Met-NH2(7)], reversed selectivity (delta-->mu); (c) substitutions at positions 4, 5, and 6 diminished selectivity, with changes in residue 5 being the most detrimental; (d) C-terminal deletions differentially effected Ki. These are the first data to demonstrate a reversal of delta selectivity in heptapeptides containing a negative charge and indicate that modifications in affinity occur through changes in both anionic and hydrophobic properties of residues at specific positions in the peptide. Deltorphin analogues might also be applied to differentiate between opioid receptor subsites.

Amino Acid Sequence↗
PubMedDate not supplied

Long-term ambient air pollution levels in four Chinese cities: inter-city and intra-city concentration gradients for epidemiological studies.

The field data collection of an air pollution epidemiologic study was carried out from 1993 to 1996 in four Chinese cities of Lanzhou, Chongqing, Wuhan, and Guangzhou. In each city, an urban district and a suburban district were selected. Ambient concentrations of total suspended particles (TSP), size-fractionated particulate matter including PM2.5, PM2.5-10, and PM10, sulfur dioxide (SO2), and oxides of nitrogen (NOx) were measured in these districts. The results indicate the presence of wide inter-city and intra-city gradients in long-term ambient levels of these measured pollutants. Across the eight districts, the 1993-1996 4-year means of TSP, SO2, and NOx ranged from 198 to 659 microg/m3, from 14.6 to 331 microg/m3, and from 31.5 to 239 microg/m3, respectively, and the 1995-1996 2-year means of PM2.5, PM2.5-10, and PM10 ranged from 51.5 to 142 microg/m3, from 29.2 to 107 microg/m3, and from 80.7 to 232 microg/m3, respectively. These pollution ranges substantially extended the upper end of the pollution ranges of previous air pollution epidemiologic studies conducted in North America and Europe. In each district, significant correlations among the measured pollutants were observed for daily concentrations. However, the gradient patterns in long-term means of different pollutants were different across the eight districts. (e.g., PM2.5-10 and TSP were highest in the Lanzhou urban district, PM2.5 and PM10 were highest in the Guangzhou urban district, SO2 was highest in the Chongqing urban district, and NOx was highest in the Guangzhou urban district). In general, seasonal variations were present in the ambient concentrations with high levels often occurring in winter months. The eight districts may be classified into four district clusters based on integrated levels of all measured pollutants. These features of the ambient air pollution have important implications for epidemiological studies and may provide unique opportunities to study exposure-effects relationships in the four Chinese cities.

Air Pollutants↗
PubMedDate not supplied

Effects of air pollution on children's pulmonary function in urban and suburban areas of Wuhan, People's Republic of China.

In May and June of 1988, the spirometric lung function of 604 children, who were aged 7-13 y and who were free of chronic respiratory conditions, was measured in the urban core and a suburb of Wuhan, China. During 1981-1988, ambient total suspended particulate (TSP) levels averaged 481 micrograms/m3 in the urban core and 167 micrograms/m3 in the suburb. In 1988, TSP levels, measured within 500 m of the children's homes, averaged 251 micrograms/m3 in the urban core and 110 micrograms/m3 in the suburb. Levels of sulfur dioxide and nitrogen oxides were also higher in the urban core. Proportions of families who burned coal and gas domestically were similar in both areas. In linear and logarithmic regression models, height was a stronger determinant of forced vital capacity and forced expiratory volume in 1 s than was age or weight. In linear models, the proportion of variance explained by height (R-squared) ranged from 0.54 for urban females' forced expiratory volume in 1 s to 0.77 for suburban males and females. Both forced vital capacity and forced expiratory volume in 1 s were consistently lower in urban than suburban children. The average forced vital capacity and forced expiratory volume in 1 s in children 132-144 cm tall were 6.7% and 3.8% lower, respectively, in the urban core than the suburb; suburban-urban differences increased with height. Suburban-urban differences in slopes of lung function growth curves were statistically significant for forced vital capacity but not for forced expiratory volume in 1 s. Rates of clinical upper respiratory irritation were also generally elevated in urban children. These results strongly suggest that urban ambient air pollution exposure in China contributes to retardation in the growth of children's lung function. Confirmatory longitudinal studies are in progress in Wuhan and three other Chinese cities.

Adolescent↗
PubMedDate not supplied

Sources of organic acids in indoor air: a field study.

Simultaneous indoor and outdoor measurements of organic acids were made at six residential houses located in a suburban New Jersey area during the summer of 1992. Each house was measured for six days and controlled for ventilation and gas combustion conditions. The study presents the first set of simultaneous measurements of formic and acetic acid in indoor and outdoor air. The concentrations of formic acid were 1.24 +/- 1.17 ppb outdoors and 8.77 +/- 4.67 ppb indoors. The concentrations of acetic acid were 3.05 +/- 3.63 ppb outdoors and 23.97 +/- 16.20 ppb indoors. The higher indoor concentrations indicated the presence of significant indoor sources such as direct emissions and indoor chemical formation. However, the results indicated that organic acids indoors were not likely to be emitted from indoor gas combustion. The study also collected temperature, humidity, ozone, aldehyde, and nitrogen dioxide data, and provided the supporting evidence for indoor chemical reaction pathways leading to organic acid formation.

Acetates↗