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S Chapman

Publications and source records attributed to S Chapman.

At least 19 recordsLinked to original sources
PubMed1992

AIDS--beyond education.

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Acquired Immunodeficiency Syndrome↗
PubMed1992

Mutational analysis of the coat protein gene of potato virus X: effects on virion morphology and viral pathogenicity.

The role of the coat protein of potato virus X (PVX) was investigated by site-directed mutation of the coat protein gene. Mutant viruses with in-frame deletions in the 5' end of the coat protein gene were capable of systemically infecting plants, but produced virions with atypical morphology. Viruses with a frameshift mutation near the 5' end or with deletions in the central part of the coat protein gene failed to accumulate at detectable levels, even in the inoculated leaf. In protoplasts, mutants that infected systemically either had a wild-type phenotype or showed a small reduction in accumulation of genomic RNA. The other mutants, which did not accumulate in the inoculated leaf, were unaffected in genomic RNA accumulation 8 hr postinoculation, but at 16 hr and later they accumulated less genomic RNA than wild-type virus. None of the mutations had an effect on accumulation of negative-strand RNA. The data indicate that efficient accumulation and spread of PVX, even in the inoculated leaf, requires coat protein production and encapsidation of the viral RNA.

Amino Acid Sequence↗
PubMed1992

Molecular analysis of a resistance-breaking strain of potato virus X.

Full-length cDNA clones of potato virus X (PVX) strains PVXUK3 and PVXHB have been constructed in plasmid vectors to allow in vitro transcription of infectious PVX RNA. In both instances the transcript-derived virus infected tobacco and potato identically to the respective progenitor strains: in tobacco and susceptible potato cultivars both strains infected systemically, producing symptomless or mild mosaic symptoms. In potato carrying the Rx or Nx resistance genes, the virus derived from the PVXHB cDNA infected systemically, whereas the virus derived from the PVXUK3 cDNA failed to infect the Rx plants or induced apical necrosis, characteristic of a hypersensitive response of the Nx gene. Three hybrid viral genomes were constructed at the cDNA level to localize the resistance breaking determinants of PVXHB. Transcripts of all three hybrids were infectious on tobacco. On potato cultivars with either the Rx or Nx resistance genes, the hybrid viruses infected in the same way as PVXHB, rather than PVXUK3. The common feature of these hybrid viruses, the coat protein gene, is therefore the determinant of Nx and Rx resistance breaking of PVXHB.

Amino Acid Sequence↗
PubMed1992

Potato virus X as a vector for gene expression in plants.

The suitability of potato virus X (PVX) as a gene vector in plants was tested by analysis of two viral constructs. In the first, the GUS gene of Escherichia coli was substituted for the viral coat protein gene. In the second, GUS was added into the viral genome coupled to a duplicated copy of the viral promoter for the coat protein mRNA. The viral construct with the substituted coat protein gene accumulated poorly in inoculated protoplasts and failed to spread from the site of infection in plants. These results suggest a role for the viral coat protein in key stages of the viral infection cycle and show that gene replacement constructs are not suitable for the production of PVX-based gene vector. The construct with GUS coupled to the duplicated promoter for coat protein mRNA also accumulated less well in protoplasts than the unmodified PVX, but did infect systemically and directed high level synthesis of GUS in inoculated and systemically infected tissue. Although there was some genome instability in the PVX construct, much of the viral RNA in the systemically infected tissue had retained the foreign gene insertion, especially in infected Nicotiana clevelandii plants. These data point to a general utility of PVX as a vector for unregulated gene expression in plants.

Base Sequence↗
PubMed1992

Dogma disputed: potential endemic heterosexual transmission of human immunodeficiency virus in Australia.

The concept of tertiary sexual transmission of human immunodeficiency virus (HIV) has been central to government efforts to communicate notions of risk to heterosexuals in Australia. Data on heterosexually transmitted acquired immune deficiency syndrome (AIDS) and HIV for Australia are reviewed with emphasis given to the probability of misclassification bias in the heterosexually acquired and 'other/undetermined' categories. Tertiary cases are almost certainly rare in Australia, with little evidence of any increase in their incidence since the first cases were recorded. Three factors (low probability of exposure, the infectivity of HIV and a comparatively low rate of sexual partner change) make it improbable that Australian heterosexuals with no risk factors will experience endemic HIV infection, with a caveat to this conclusion lying in the potential of Australian sex tourism to Southeast Asia for introducing HIV into the Australian heterosexual population. Four hegemonic factors which have acted to suppress any serious debate of the notion that HIV in Australia is unlikely to become endemic among heterosexuals are discussed: the political 'democratization' of risk inspired by concerns that gay men should not be further vilified as a victim group; the preventive imperative; a reluctance among health educators to question the very foundations of the message they are employed to deliver; and a reluctance to curtail 'Trojan horse' benefits to sexually transmissible disease prevention engendered by HIV education promoting safe sex messages.

Adult↗
PubMed1992

Media sources of HIV/AIDS information in injecting drug users.

We report on media habits of 797 members of a sample of 1245 injecting drug users interviewed in Sydney, Australia. While preferred hours of television viewing and radio listening were similar to those of the general population, the preferred channels and stations were different. These findings could assist in targeting injecting drug users with information about HIV/AIDS prevention. However as the self-regulatory advertising process has constrained broadcast and publication of overt messages directed at homosexual and bisexual men, similar restrictions may prevent optimal mass media approaches to educating this other important group at risk of HIV infection.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Trends in tans and skin protection in Australian fashion magazines, 1982 through 1991.

We rated 3971 photographs of models from midsummer editions of six Australian fashion magazines from 1982-1983 to 1990-1991 for tan on a 9-point scale, for the presence of hats, for sun-protective clothing, and for shade setting. With the exception of the 1990-1991 sample, there was an increasing proportion of light tans over the years. Men were more likely to be deeply tanned than were women. The proportion of models wearing hats followed an increasing linear trend across the five periods. Three quarters of the outdoor photographs were taken in unshaded settings. In unshaded settings, 17% of the women and 5% of the men wore hats.

Australia↗
PubMed1991

Long-term response of recurrent respiratory papillomatosis to treatment with lymphoblastoid interferon alfa-N1. Papilloma Study Group.

BACKGROUND: We earlier reported that patients with recurrent respiratory papillomatosis responded to six months of treatment with lymphoblastoid interferon alfa-n1. Because another study of patients treated for one year with leukocyte interferon alfa-n3 found that the growth rate of papillomas was slowed in the first six months but returned to base line during months 7 through 12 despite persistent interferon treatment, we now report the long-term results in our original study patients who were followed for a median of four years after the original one-year crossover study. METHODS: After the patients in our study had completed the first study year, their physicians could continue or recommence treatment with lymphoblastoid interferon alfa-n1 in a dose of either 2 MU per square meter of body-surface area per day or 4 MU per square meter every other day. The extent of disease was measured by endoscopy when clinically indicated. RESULTS: Data on late-follow-up were obtained for 60 of the 66 patients. There were 22 complete remissions and 25 partial remissions; 13 patients had no response. The median duration of the complete remissions was 550 days, and 15 patients continued to be in complete remission. The median duration of partial remissions was 400 days and seven patients were still in partial remission. Thirteen of 28 patients responded to a second course of interferon after an interruption in treatment of at least one month. The rate of response in the 11 of 53 patients who had neutralizing antibody to interferon was the same as in the patients without the antibody. CONCLUSIONS: Patients with severe recurrent respiratory papillomatosis may have a sustained or repeated response to treatment with lymphoblastoid interferon alfa-n1. We recommend that patients with recurrent respiratory papillomatosis who require surgery every two to three months be given a six-month trial of interferon alfa-n1.

Adolescent↗