Assessing, valuing and protecting our environment- is there a statistical challenge to be answered?

This short article describes some of the evolution in environmental regulation, management and monitoring and the information needs, closely aligned to the statistical challenges to deliver the evidence base for change and effect

Splenic Haemorrhage Complicating Pregnancy.*

n/

The strength and timing of the mitochondrial bottleneck in salmon suggests a conserved mechanism in vertebrates

In most species mitochondrial DNA (mtDNA) is inherited maternally in an apparently clonal fashion, although how this is achieved remains uncertain. Population genetic studies show not only that individuals can harbor more than one type of mtDNA (heteroplasmy) but that heteroplasmy is common and widespread across a diversity of taxa. Females harboring a mixture of mtDNAs may transmit varying proportions of each mtDNA type (haplotype) to their offspring. However, mtDNA variants are also observed to segregate rapidly between generations despite the high mtDNA copy number in the oocyte, which suggests a genetic bottleneck acts during mtDNA transmission. Understanding the size and timing of this bottleneck is important for interpreting population genetic relationships and for predicting the inheritance of mtDNA based disease, but despite its importance the underlying mechanisms remain unclear. Empirical studies, restricted to mice, have shown that the mtDNA bottleneck could act either at embryogenesis, oogenesis or both. To investigate whether the size and timing of the mitochondrial bottleneck is conserved between distant vertebrates, we measured the genetic variance in mtDNA heteroplasmy at three developmental stages (female, ova and fry) in chinook salmon and applied a new mathematical model to estimate the number of segregating units (N(e)) of the mitochondrial bottleneck between each stage. Using these data we estimate values for mtDNA Ne of 88.3 for oogenesis, and 80.3 for embryogenesis. Our results confirm the presence of a mitochondrial bottleneck in fish, and show that segregation of mtDNA variation is effectively complete by the end of oogenesis. Considering the extensive differences in reproductive physiology between fish and mammals, our results suggest the mechanism underlying the mtDNA bottleneck is conserved in these distant vertebrates both in terms of it magnitude and timing. This finding may lead to improvements in our understanding of mitochondrial disorders and population interpretations using mtDNA data

Mast cells in human periodontal disease

Recently, mast cells have been shown to produce cytokines which can direct the development of T-cell subsets. The aim of the present study was to determine the relationship between mast cells and the Th1/Th2 response in human periodontal disease. Tryptase+ mast cell numbers were decreased in chronic periodontitis tissues compared with healthy/gingivitis lesions. Lower numbers of c-kit+ cells, which remained constant regardless of clinical status, indicate that there may be no increased migration of mast cells into periodontal disease lesions. While there were no differences in IgG2+ or IgG4+ cell numbers in healthy/gingivitis samples, there was an increase in IgG4+ cells compared with IgG2+ cells in periodontitis lesions, numbers increasing with disease severity. This suggests a predominance of Th2 cells in periodontitis, although mast cells may not be the source of Th2-inducing cytokines

Will the Scottish Cancer Target for the year 2000 be met? The use of cancer registration and death records to predict future cancer incidence and mortality in Scotland.

Cancer mortality data reflect disease incidence and the effectiveness of treatment. Incidence data, however, reflect the burden of disease in the population and indicate the need for prevention measures, diagnostic services and cancer treatment facilities. Monitoring of targets mandates that both be considered. The Scottish Cancer Target, established in 1991, proposed that a reduction of 15% in mortality from cancer in the under-65s should be achieved between 1986 and 2000. Each year in Scotland approximately 8300 persons under 65 are diagnosed with cancer and 4500 die from the disease. The most common malignancies, in terms of both incident cases and deaths, in the under-65s, are lung and large bowel cancer in males, and breast, large bowel and lung cancer in females. A decrease of 6% in the number of cancer cases diagnosed in males under 65 is predicted between 1986 and 2000, whereas the number of cases in females in the year 2000 is expected to remain at the 1986 level. In contrast, substantial reductions in mortality are expected for both sexes: 17% and 25% in males and females respectively. Demographic changes will influence the numbers of cancer cases and deaths in the Scottish population in the year 2000. However, long-term trends in the major risk factors, such as smoking, are likely to be the most important determinants of the future cancer burden

Measuring vertebrate telomeres: applications and limitations

Telomeres are short tandem repeated sequences of DNA found at the ends of eukaryotic chromosomes that function in stabilizing chromosomal end integrity. In vivo studies of somatic tissue of mammals and birds have shown a correlation between telomere length and organismal age within species, and correlations between telomere shortening rate and lifespan among species. This result presents the tantalizing possibility that telomere length could be used to provide much needed information on age, ageing and survival in natural populations where longitudinal studies are lacking. Here we review methods available for measuring telomere length and discuss the potential uses and limitations of telomeres as age and ageing estimators in the fields of vertebrate ecology, evolution and conservation

Inflammation, heat shock proteins and periodontal pathogens in atherosclerosis: an immunohistologic study

Background: Inflammation is a significant component of atherosclerosis lesions. Bacteria, including periodontopathogens, have been demonstrated in atherosclerotic plaques and cross-reactivity of the immune response to bacterial GroEL with human heat shock protein 60 has been suggested as a link between infections and atherosclerosis

Inflammation, heat shock proteins and periodontal pathogens in atherosclerosis: an immunohistologic study

Background: Inflammation is a significant component of atherosclerosis lesions. Bacteria, including periodontopathogens, have been demonstrated in atherosclerotic plaques and cross-reactivity of the immune response to bacterial GroEL with human heat shock protein 60 has been suggested as a link between infections and atherosclerosis

Excitation and relaxation in atom-cluster collisions

Electronic and vibrational degrees of freedom in atom-cluster collisions are treated simultaneously and self-consistently by combining time-dependent density functional theory with classical molecular dynamics. The gradual change of the excitation mechanisms (electronic and vibrational) as well as the related relaxation phenomena (phase transitions and fragmentation) are studied in a common framework as a function of the impact energy (eV...MeV). Cluster "transparency" characterized by practically undisturbed atom-cluster penetration is predicted to be an important reaction mechanism within a particular window of impact energies.Comment: RevTeX (4 pages, 4 figures included with epsf