Premature burial : fact or fiction?

Mode of access: Internet.

Chalfont St. Giles : past and present : with the Parish Church, Milton's cottage and Jordans, the Quakers' burial ground /

Mode of access: Internet.

Multiple genotypes of Chlamydia pneumoniae identified in human carotid plaque

Chlamydia pneumoniae is an obligate intracellular respiratory pathogen that causes 10% of community-acquired pneumonia and has been associated with cardiovascular disease. Both whole-genome sequencing and specific gene typing suggest that there is relatively little genetic variation in human isolates of C. pneumoniae. To date, there has been little genomic analysis of strains from human cardiovascular sites. The genotypes of C. pneumoniae present in human atherosclerotic carotid plaque were analysed and several polymorphisms in the variable domain 4 (VD4) region of the outer-membrane protein-A (ompA) gene and the intergenic region between the ygeD and uridine kinase (ygeD-urk) genes were found. While one genotype was identified that was the same as one reported previously in humans (respiratory and cardiovascular), another genotype was found that was identical to a genotype from non-human sources (frog/koala).

Burial depth and cultivation influence emergence and persistence of Phalaris paradoxa seed in an Australian sub-tropical environment

Emergence and persistence characteristics of Phalaris paradoxa seeds in no- and minimum-till situations and at different burial depths were studied in a sub-tropical environment. Three experiments were carried out using naturally shed seeds. In the first experiment, seedlings emerged from May through to September each year, although the majority of seedlings emerged in July. In the second experiment with greater seed density, cultivation in March of each year stimulated seedling emergence, altered the periodicity of emergence and accelerated the decline of seeds in the seedbank compared with plots that received no cultivation. The majority of seedlings in the cultivated plots emerged in May whereas the majority of seedlings in the undisturbed plots emerged in July. Emergence accounted for only 4-19% of the seedbank in both experiments over 2 years. Seed persistence was short in both field experiments, with less than 1% remaining 2 years after seed shed. In the third experiment, burial depth and soil disturbance significantly influenced seedling emergence and persistence of seed. Seedlings emerged most from seed mixed in the top 10 cm when subjected to annual soil disturbance, and from seed buried at 2.5 and 5.0 cm depths in undisturbed soil. Emergence was least from seed on the soil surface, and buried at 10 and 15 cm depths in undisturbed soil. Seeds persisted longest when shed onto the soil surface and persisted least when the soil was tilled. These results suggest that strategic cultivation may be a useful management tool, as it will alter the periodicity of emergence allowing use of more effective control options and will deplete the soil seedbank more rapidly.

Effect of soil burial depth and wetting on mortality of diapausing larvae and patterns of post-diapause adult emergence of sorghum midge, Stenodiplosis sorghicola (Coquillett) (Diptera : Cecidomyiidae)

In south-eastern Queensland, Australia, sorghum planted in early spring usually escapes sorghum midge, Stenodiplosis sorghicola, attack. Experiments were conducted to better understand the role of winter diapause in the population dynamics of this pest. Emergence patterns of adult midge from diapausing larvae on the soil surface and at various depths were investigated during spring to autumn of 1987/88-1989/90. From 1987/88 to 1989/90, 89%, 65% and 98% of adult emergence, respectively, occurred during November and December. Adult emergence from larvae diapausing on the soil surface was severely reduced due to high mortality attributed to surface soil temperatures in excess of 40 degrees C, with much of this mortality occurring between mid-September and mid-October. Emergence of adults from the soil surface was considerably delayed in the 1988/89 season compared with larvae buried at 5 or 10 cm which had similar emergence patterns for all three seasons. In 1989/90, when a 1-cm-deep treatment was included, there was a 392% increase in adult emergence from this treatment compared with deeper treatments. Some diapausing larvae on the surface did not emerge at the end of summer in only 1 year (1989/90), when 28.0% of the larvae on the surface remained in diapause, whereas only 0.8% of the buried larvae remained in diapause. We conclude that the pattern of emergence explains why spring plantings of sorghum in south-eastern Queensland usually escape sorghum midge attack.

Modelling Apoptotic cell clearance within the atherosclerotic plaque

The aged population have an increased susceptibility to infection, therefore function of the innate immune system may be impaired as we age. Macrophages, and their precursors monocytes, play an important role in host defence in the form of phagocytosis, and also link the innate and adaptive immune system via antigen presentation. Classically-activated 'M1' macrophages are pro-inflammatory, which can be induced by encountering pathogenic material or pro-inflammatory mediators. Alternatively activated 'M2' macrophages have a largely reparative role, including clearance of apoptotic bodies and debris from tissues. Despite some innate immune receptors being implicated in the clearance of apoptotic cells, the process has been observed to have a dominant anti-inflammatory phenotype with cytokines such as IL-10 and TGF-ß being implicated. The atherosclerotic plaque contains recruited monocytes and macrophages, and is a highly inflammatory environment despite high levels of apoptosis. At these sites, monocytes differentiate into macrophages and gorge on lipoproteins, resulting in formation of 'foam cells' which then undergo apoptosis, recruiting further monocytes. This project seeks to understand why, given high levels of apoptosis, the plaque is a pro-inflammatory environment. This phenomenon may be the result of the aged environment or an inability of foam cells to elicit an anti-inflammatory effect in response to dying cells. Here we demonstrate that lipoprotein treatment of macrophages in culture results in reduced capacity to clear apoptotic cells. The effect of lipoprotein treatment on apoptotic cell-mediated immune modulation of macrophage function is currently under study.

Reduced transferrin binding in Down syndrome:a route to senile plaque formation and dementia

Plasma transferrin binding in Down syndrome and Alzheimer's disease is significantly reduced compared with age matched controls and it was thought this may help elucidate a pathological time sequence for the onset of dementia in Down syndrome. In Down syndrome, there was a reduction in gallium and aluminium transferrin binding both with age and the onset of dementia. Non-transferrin bound gallium species were identified as non-transportable phosphate or silicate. Thus, the route of entry of metals into the brain must be via a transferrin mediated complex only. A clear sequence of pathological events has been demonstrated in Down syndrome which shows the pathway to development of plaques and dementia and this is believed to have an immunological origin.