PubMed Health⌕ Search

Biomedical subjects

J S Mackenzie

Publications and source records attributed to J S Mackenzie.

121 records · Page 7Linked to original sources
PubMed1969

Virulence of temperature-sensitive mutants of influenza virus.

The acquisition of temperature-mutant (ts) defects in a strain of influenza virus has been shown in mice to be associated with diminished virulence, though the antibody-producing stimulus remained. It is suggested that three advantages may make ts strains potential sources of attenuated live influenza vaccine-the ease of obtaining the strains, the ease of testing the vaccine strain, and the high yield of vaccine doses from a single egg.

Animals↗
PubMedDate not supplied

An orthodontic evaluation of 16-year-old males with an original complete unilateral cleft lip and palate problem repaired during the neonatal period.

A cephalometric analysis is presented of a group of 21 16-year-old males born with complete unilateral clefts of lip and palate with surgical repair carried out in the neonatal period. Comparisons are made with the multicentre study reported by Ross (1987). The study demonstrates that the effect of early surgery on facial growth is similar to that of the average of the multicentre study.

Adolescent↗
PubMedDate not supplied

Japanese encephalitis on Badu Island, Australia: the first isolation of Japanese encephalitis virus from Culex gelidus in the Australasian region and the role of mosquito host-feeding patterns in virus transmission cycles.

During investigation of an outbreak of Japanese encephalitis (JE) in the Torres Strait, Australia, in 2000, mosquitoes were collected in Badu Island community and at a newly established communal piggery about 3 km from the community. A total of 94,285 mosquitoes, comprising 91,240 (96.8%) unengorged females, 1630 (1.7%) blood-engorged females and 1415 (1.5%) males, were processed for virus isolation. One isolate of JE virus was obtained from Culex gelidus, with a minimum infection rate of 12.4:1000. This is the first isolate of JE virus from Cx. gelidus in the Australasian region. No isolates were obtained from Cx. annulirostris, the primary implicated Australian JE vector. Analysis of mosquito host-feeding patterns, using gel diffusion, demonstrated that Cx. annulirostris and 5 other species fed predominately on mammals. Analysis of blood-fed mosquitoes collected within the community demonstrated that the proportion of Cx. annulirostris feeding on pigs in 2000 (2.3%) was significantly lower than that for the 1995-97 period (31.3%). The removal of the pigs from Badu Island community has limited the contact between potential amplifying hosts and mosquitoes, thus potentially reducing the risk of transmission of JE virus to the human population.

Animals↗
PubMedDate not supplied

The relationships between West Nile and Kunjin viruses.

Until recently, West Nile (WN) and Kunjin (KUN) viruses were classified as distinct types in the Flavivirus genus. However, genetic and antigenic studies on isolates of these two viruses indicate that the relationship between them is more complex. To better define this relationship, we performed sequence analyses on 32 isolates of KUN virus and 28 isolates of WN virus from different geographic areas, including a WN isolate from the recent outbreak in New York. Sequence comparisons showed that the KUN virus isolates from Australia were tightly grouped but that the WN virus isolates exhibited substantial divergence and could be differentiated into four distinct groups. KUN virus isolates from Australia were antigenically homologous and distinct from the WN isolates and a Malaysian KUN virus. Our results suggest that KUN and WN viruses comprise a group of closely related viruses that can be differentiated into subgroups on the basis of genetic and antigenic analyses.

Aedes↗
PubMedDate not supplied

Flaviviruses isolated from mosquitoes collected during the first recorded outbreak of Japanese encephalitis virus on Cape York Peninsula, Australia.

In response to an outbreak of Japanese encephalitis (JE) virus on Cape York Peninsula, Australia, in 1998, mosquitoes were collected using CO2 and octenol-baited Centers for Disease Control and Prevention light traps. A total of 35,235 adult mosquitoes, comprising 31 species, were processed for virus isolation. No isolates of JE virus were recovered from these mosquitoes. However, 18 isolates of Kokobera virus, another flavivirus were obtained from Culex annulirostris. Twelve isolates were from western Cape York (minimum infection rate (MIR) of 0.61: 1,000 mosquitoes) and 6 were from the Northern Peninsula Area (MIR of 1.0:1,000). Potential explanations for the failure to detect JE virus in mosquitoes collected from Cape York Peninsula include the timing of collections, the presence of alternative bloodmeal hosts, differences in pig husbandry, asynchronous porcine seroconversion, and the presence of other flaviviruses.

Animals↗
PubMedDate not supplied

Host factors and susceptibility to influenza A infection: the effect of ABO blood groups and HL-A antigens.

The effect of two host genetic factors on the outcome of influenza A infections has been examined, ABO blood groups and HL-A antigens. A significantly higher proportion of blood group B subjects was found to have serological evidence of infection with epidemic influenza despite a high incidence of residual antibody among the volunteers. No difference was observed in the ability of subjects of different blood groups to seroconvert after receiving two doses of live attenuated influenza A vaccine, but a significantly higher proportion of blood group A vaccines seroconverted after receiving their first dose of vaccine. The association between HL-A type BW16 and resistance to infection with influenza could not be confirmed. The results are discussed in terms of an indirect association between susceptibility to influenza infection and the two host genetic factors.

ABO Blood-Group System↗
PubMedDate not supplied

Influenza A virus and its influence on the outcome of pregnancy in the mouse.

The effect of sub-lethal doses of influenza A strains WSN (H0N1), MEL (H0N1) and MRC-7 (H3N2) administered intranasally during pregnancy was studied in C3H inbred and Prince Henry outbred mice. Maternal and neonatal mortality rates were significantly increased by infections in the last third of the gestational period. Infection with influenza strain WSN in the last part of the first third of the gestational period significantly depressed the growth rate of neonates. No evidence of viraemia, transplacental transmission or congenital malformations were observed. Invasion of alveolar spaces by mononuclear phagocytes and erythrocytes was more pronounced in pregnant mice infected in the last third of the gestational period than in non-pregnant mice, and paralleled an ablation of cell-mediated immune responsiveness.

Animals↗