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Biomedical subjects

P Broadbent

Publications and source records attributed to P Broadbent.

12 recordsLinked to original sources
PubMed2001

The development of the HIV epidemic in Karonga District, Malawi.

OBJECTIVE: To investigate the prevalence and sociodemographic risk factors for HIV infection, during the early stages of the epidemic, in a rural area of northern Malawi. METHODS: As part of a community-based study of mycobacteria, socioeconomic data and HIV results are available on approximately 30,000 individuals from random population samples in 1981-1984 and 1987-1989 from a rural area of Malawi. These have been analysed to characterize the early stages of the HIV epidemic. RESULTS: The earliest HIV-positive specimens were collected in 1982. HIV prevalence in individuals aged 15-49 years was 0.1% in the early 1980s and 2.0% in the late 1980s. In the early 1980s, eight out of 11 HIV-positive individuals were new immigrants to the district or had recently returned there. In the late 1980s, immigration and having spent time outside the district continued to be major risk factors for HIV. HIV infection was more common in those with occupations other than subsistence farming, in those with more schooling, and in those in the best housing. The association with schooling was seen at all ages for both men and women. CONCLUSION: Immigration and travel were important in the repeated introduction and establishment of the HIV epidemic. The association with schooling is similar to that found elsewhere in Africa.

Adolescent↗
PubMed1996

No increased prevalence of adrenocortical insufficiency in human immunodeficiency virus-associated tuberculosis.

SETTING: Acute medical wards, Kenyatta National Hospital, Nairobi, Kenya. OBJECTIVE: To determine the prevalence of adrenocortical insufficiency in human immunodeficiency virus (HIV)-1 infected and non-infected patients with tuberculosis. DESIGN: One hundred and seventy-four patients with proven tuberculosis (90 HIV-1 positive and 84 HIV-1 negative) were assessed for adrenocortical insufficiency with a 30 min synacthen stimulation test. RESULTS: Fifty-one percent of those with pulmonary tuberculosis and 56% of those with extra-pulmonary tuberculosis had a subnormal cortisol response. However there was no statistically significant difference between the HIV-1 infected and non-infected patients in either group. CONCLUSION: While an impaired cortisol response is common in tuberculosis, it is no more prevalent in HIV-1 infected patients than non-infected patients with tuberculosis.

AIDS-Related Opportunistic Infections↗
PubMed1996

Manipulation of glutathione metabolism in transgenic plants.

There is clear potential for the genetic manipulation of key enzymes involved in stress metabolism in transgenic plants. However, the data emerging so far from such experiments are equivocal. The detailed analysis of stress responses in progeny of primary transgenics, coupled with comparisons with control transgenic plants that do not contain the GR transgene, allows us to take into account the possible variation in response to stress associated with regeneration of plants from tissue culture. The picture that is now beginning to emerge with respect to the role of GR in stress protection is that, although there are clearly benefits to be had from overexpression of the enzymes, there is no direct correlation between enzyme levels and stress tolerance. It may be that overexpression of the cytosolic isoform (gor2) will prove to be of greater benefit. Furthermore, the types of stresses to which transgenic plants have been exposed in order to assess the consequences of oxidative stress tolerance cannot reproduce those that will experienced in field conditions. Only when plants with higher GR levels and increased glutathione synthesis capacity are grown in field trials will it be possible to make a full assessment of the benefits of engineering plants with altered glutathione metabolism.

Amino Acid Sequence↗
PubMed1993

Characterisation of isolates and strains of citrus tristeza closterovirus using restriction analysis of the coat protein gene amplified by the polymerase chain reaction.

Citrus Tristeza Virus (CTV) exists as a large number of distinct strains differing in biological properties and with different distributions in citrus producing countries. Strategies such as eradication or cross protection, aimed at controlling severe variants of the pathogen, require procedures to identify virus strains accurately and reliably. To fill the need for a rapid, reproducible assay, we have investigated the use of restriction analysis of the CTV coat protein gene amplified using the polymerase chain reaction (PCR). The primers 5' ATG GAC GAC GAA ACA AAG 3' and 5' TCA ACG TGT GTT GAA TTT 3' amplified a DNA copy of the CTV coat protein gene (approx. 670 base pairs) when used in a reverse transcriptase PCR assay. Amplifications were carried out using dsRNA prepared from field and indicator plants, or from single-stranded RNA prepared from crude PEG precipitates of intact virions. All 51 CTV isolates tested produced an amplified product of the same size, regardless of country of origin or biological properties. Digestion of the amplified coat protein genes with the restriction enzymes Hinf1 or Rsa1 revealed sequence variation in the PCR products. Hinf1 provided the best discrimination between strains, defining seven Restriction Fragment Length Polymorphism (RFLP) groups, some of which circumscribed sets of isolates with similar biological properties. Limited analysis of field isolates using this method showed that individual trees could contain mixtures of CTV strains, as assessed by the recovery of several RFLP types from individual reactions. Single aphid transmissions of isolates usually, but not always, generated apparently pure single strains judged by the recovery of single RFLP groups.

Animals↗
PubMed1988

Relationship between glutamine concentration and protein synthesis in rat skeletal muscle.

Muscle glutamine concentration ([GLN]) and protein synthesis rate (Ks) have been examined in vivo in well-fed, protein-deficient, starved, and endotoxemic rats. With protein deficiency (8 or 5% casein diet), [GLN] fell from 7.70 to 5.58 and 3.56 mmol/kg in the 8 and 5% diet groups, with Ks falling from 15.42 to 9.1 and 6.84%/day. Three-day starvation reduced [GLN] and Ks to 2.38 mmol/kg and 5.6%/day, respectively. In all these groups food intakes and insulin were generally well maintained (except in the starved group), whereas free 3,5,3'-triiodothyronine (T3) was depressed in the starved and 5% protein group. The E. coli lipopolysaccharide endotoxin (3 mg/kg) reduced [GLN] to 5.85 and 4.72 mmol/kg and Ks to 10.5 and 9.10%/day in two well-fed groups. Insulin levels were increased, and free T3 levels fell. Combined protein deficiency and endotoxemia further reduced [GLN] and Ks to 1.88 mmol/kg and 4.01%/day, respectively, in the 5% protein rats. Changes in both ribosomal activity (KRNA) and concentration (RNA/protein) contributed to the fall in Ks in malnutrition and endotoxemia, although reductions in the RNA concentration were most marked with protein deficiency and reductions in the KRNA dominated the response to the endotoxin. The changes in [GLN] and Ks were highly correlated as were [GLN] and both KRNA and the RNA concentration, and these relationships were unique to glutamine. These relationships could reflect sensitivity of glutamine transport and protein synthesis to the same regulatory influences, and the particular roles of insulin and T3 are discussed, as well as any direct influence of glutamine on protein synthesis.

Animals↗