University of Aberdeen

About: University of Aberdeen is a education organization based out in Aberdeen, United Kingdom. It is known for research contribution in the topics: Population & Health care. The organization has 21174 authors who have published 49962 publications receiving 2105479 citations. The organization is also known as: Aberdeen University.

How old is streamwater? Open questions in catchment transit time conceptualization, modelling and analysis

Abstract: The time water spends travelling subsurface through a catchment to the stream network (i.e. the catchment water transit time) fundamentally describes the storage, flow pathway heterogeneity and sou ...

Thrifty genes for obesity, an attractive but flawed idea, and an alternative perspective: the 'drifty gene' hypothesis.

Abstract: Almost 50 years ago Neel proposed a hypothesis to explain the prevalence of obesity and diabetes in modern societyFthe ‘thrifty gene’ hypothesis. The fundamental basis of the hypothesis was that, in our early evolutionary history, genes, that promoted efficient fat deposition would have been advantageous because they allowed their holders to survive at periods of famine. In modern society, such genes are disadvantageous because they promote fat deposition in preparation for a famine that never comes, and the result is widespread obesity and diabetes. In recent years I, and others, have questioned some of the fundamental assumptions of this hypothesisFparticularly focusing on whether differential survival of lean against obese in famines provides sufficient selective pressure for the spread of so-called ‘thrifty genes’. These arguments have been criticized because famines not only affect survival but also fecundity, and obese people would be expected to sustain fecundity longer in the face of food shortages. In this paper, I show that the reduced fecundity argument is flawed because famines are almost universally followed by periods of enhanced fecundity, which offsets the decline observed during the famine itself. The net effect of famines on fecundity is consequently insufficient to rescue the thrifty gene idea. Elsewhere, I have suggested an alternative scenario that subsections of the population have a genetic predisposition to obesity due to an absence of selection, combined with genetic drift. The scenario presented earlier was based on evidence from prehistory concerning the release of our ancestors from heavy predation pressure around 2 million years ago. I suggest here that this is one of a number of potential scenarios based on random genetic drift that may explain the specific aetiology of the obesity epidemic. Together, these alternatives, based on central notion that genetic drift rather than positive selection was a dominant factor, may be called the ‘drifty gene’ hypothesis.

The purification and properties of cyclohexanone oxygenase from Nocardia globerula CL1 and Acinetobacter NCIB 9871.

Abstract: 1 Cyclohexanone oxygenases from Nocardia globerula CL1 and Acinetobacter NCIB 9571 have been purified 12-fold and 35-fold respectively and each gives a single symmetrical sedimentation peak in the ultracentrifuge and a single protein band on 2.25 nm average pore radius polyacrylamide gels. 2 The enzyme from N. globerula has a molecular weight of 53000 while that from Acinetobacter has a molecular weight of about 59000. Each is a single polypeptide chain with one mole of bound FAD per mole of protein that does not dissociate during purification. Acidification of the Acinetobacter enzyme in the presence of (NH4)2SO4 releases the bound FAD and yields native apoenzyme from which the active holoenzyme can be reconstituted. The apparent dissociation constant for the FAD is 40 nM. 3 The near unitary stoichiometry of cyclohexanone, NADPH and oxygen consumption is typical of mixed function oxygenases with external electron donors. The oxygenated product has been identified as 1-oxa-2-oxocycloheptane thus placing these enzymes in the small group of lactone and ester-forming oxygenases. Their correct systematic name is cyclohexanone. NADPH: oxygen oxidoreductase (1,2-lactonizing) (EC 1.14.13.-). 4 A functionally essential sulfhydryl group is present at the catalytic centre of both enzymes but there is no reliable indication from inhibitor studies that they contain any functional metal ion. The three titratable sulfhydryl groups of the Acinetobacter enzyme are not equivalent since reaction with one of them selectively inhibits catalytic activity. Protection against sulfhydryl active agents is afforded by NADPH but not by cyclohexanone. 5 The N. globerula enzyme has a pH optimum of 8.4, apparent Km values of 1.56 μM and 31.3 μM for cyclohexanone and NADPH respectively and a catalytic centre activity of 1018 ml substrate transformed × mol enzyme−1× min−1. The Acinetobacter enzyme has a pH optimum of 9.0, apparent Km values of 6.9 tM and 17.8 μM and a catalytic centre activity of 1390 mol × mol enzyme−1× min−1. Both enzymes display absolute specificity for electron donor which contrasts with the broad specificity for ketone substrate. 6 An enzyme-cyclohexanone complex has been detected by difference spectroscopy only in the case of the Nocardia enzyme. Rapid reduction of the enzyme-bound FAD occurs upon addition of NADPH in the absence of cyclohexanone. Titration of enzyme with NADPH under anaerobic conditions and anaerobic photoreduction in the presence of EDTA have not revealed the formation of any stable flavin semiquinones. 7 These enzymes bear a strong resemblance to several of the monooxygenases that hydroxylate aromatic compounds.

Long-term follow-up of breast cancer survivors with post-mastectomy pain syndrome.

Abstract: Post-mastectomy pain syndrome (PMPS) is a recognised complication of breast surgery although little is known about the long-term outcome of this chronic pain condition. In 1996, Smith et al identified a prevalence rate of PMPS of 43% among 408 women in the Grampian Region, Northeast Scotland. The aim of this study was to assess long-term outcome at 7–12 years postoperatively in this cohort of women, to describe the natural history of PMPS and impact of pain upon quality of life. Chronic pain and quality of life were assessed using the McGill Pain Questionnaire (MPQ) and Short Form-36 (SF-36). Of 175 women reporting PMPS in 1996, 138 were eligible for questionnaire follow-up in 2002. Mean time since surgery was 9 years (s.d. 1.8 years). A response rate of 82% (113 out of 138) was achieved; 59 out of 113 (52%) women reported continued PMPS and 54 out of 113 (48%) women reported their PMPS had resolved since the previous survey in 1996. Quality of life scores were significantly lower in women with persistent PMPS compared to those women whose pain had resolved. However, for women with persistent PMPS, SF-36 scores had improved over time. Risk factors for persistent PMPS included younger age and heavier weight. This study found that, of women reporting PMPS in 1996, half of those surveyed in 2002 continued to experience PMPS at a mean of 9 years after surgery.

The increase in the prevalence of asthma and allergy: food for thought

Abstract: Since about 1960, the prevalence of asthma and allergic disease has increased sufficiently to become a major public-health concern. Concurrently, there have been marked changes in our diet, and it has been proposed that these changes have contributed to the increase in the prevalence of asthma and allergy. In this article, these hypotheses about diet are described, together with the postulated mechanisms and the evidence for and against, leading to the most recent evidence indicating that maternal diet during pregnancy might be particularly important in the development of childhood asthma.