Old Age in Transition: The Geriatric Ward Revisited

Old Age in Transition: The Geriatric Ward Revisited. Peter Woolfson. Westport, CT: Bergin & Garvey, 1997.133 pp.     

Clinical Problems: Sextuplet Pregnancy

In a sextuplet pregnancy which followed gonadotrophin therapy the principal problems were threatened abortion, premature labour, and placental insufficiency. Delivery was by caesarean section soon after the onset of labour at 32 weeks. The five liveborn babies thrived. The sixth was a macerated stillbirth.     

Adding Years to Your Life (or at Least Looking Like It): A Simple Normalization Underlies Adaptation to Facial Age

Adaptation has been widely used to probe how experience shapes the visual encoding of faces, but the pattern of perceptual changes produced by adaptation and the neural mechanisms these imply remain poorly characterized. We explored how adaptation alters the perceived age of faces, a fundamental facial attribute which can uniquely and reliably be scaled by observers. This allowed us to measure how adaptation to one age level affected the full continuum of perceived ages. Participants guessed the ages of faces ranging from 18–89, before or after adapting to a different set of faces composed of younger, older, or middle-aged adults. Adapting to young or old faces induced opposite linear shifts in perceived age that were independent of the model''s age. Specifically, after adapting to younger or older faces, faces of all ages appeared 2 to 3 years older or younger, respectively. In contrast, middle-aged adaptors induced no aftereffects. This pattern suggests that adaptation leads to a simple and uniform renormalization of age perception, and is consistent with a norm-based neural code for the mechanisms mediating the perception of facial age.     

Darwinian gradualism and its limits: The development of Darwin's views on the rate and pattern of evolutionary change

Conclusion The major tenets of the recent hypothesis of punctuated equilibrium are explicit in Darwin's writing. His notes from 1837–1838 contain references to stasis and rapid change. In the first edition of the Origin (1859), Darwin described the importance of isolation of local varieties in the process of speciation. His views on the tempo of speciation were influenced by Hugh Falconer and also, perhaps, by Edward Suess (1831–1914). It is paradoxical that, although both topics were recorded in his unpublished notes of 1837–1838, the second was not explicitly and fully discussed until the fourth edition of the Origin (1866). While no wholly satisfactory explanation of this paradox suggests itself, it seems probable that Falconer's work on the persistence of fossil species of elephant helped Darwin to see the wider significance of the tempo of evolution for his general theory.     

Biochemical Conservation and Evolution of Germacrene A Oxidase in Asteraceae

Sesquiterpene lactones are characteristic natural products in Asteraceae, which constitutes ∼8% of all plant species. Despite their physiological and pharmaceutical importance, the biochemistry and evolution of sesquiterpene lactones remain unexplored. Here we show that germacrene A oxidase (GAO), evolutionarily conserved in all major subfamilies of Asteraceae, catalyzes three consecutive oxidations of germacrene A to yield germacrene A acid. Furthermore, it is also capable of oxidizing non-natural substrate amorphadiene. Co-expression of lettuce GAO with germacrene synthase in engineered yeast synthesized aberrant products, costic acids and ilicic acid, in an acidic condition. However, cultivation in a neutral condition allowed the de novo synthesis of a single novel compound that was identified as germacrene A acid by gas and liquid chromatography and NMR analyses. To trace the evolutionary lineage of GAO in Asteraceae, homologous genes were further isolated from the representative species of three major subfamilies of Asteraceae (sunflower, chicory, and costus from Asteroideae, Cichorioideae, and Carduoideae, respectively) and also from the phylogenetically basal species, Barnadesia spinosa, from Barnadesioideae. The recombinant GAOs from these genes clearly showed germacrene A oxidase activities, suggesting that GAO activity is widely conserved in Asteraceae including the basal lineage. All GAOs could catalyze the three-step oxidation of non-natural substrate amorphadiene to artemisinic acid, whereas amorphadiene oxidase diverged from GAO displayed negligible activity for germacrene A oxidation. The observed amorphadiene oxidase activity in GAOs suggests that the catalytic plasticity is embedded in ancestral GAO enzymes that may contribute to the chemical and catalytic diversity in nature.     

Epizootic characteristics of hepatic and renal lesions in English sole, Parophrys vetulus, from Puget Sound

English sole, Parophrys vetulus , from eight locations within Puget Sound, U.S.A. were examined for histological abnormalities of the liver and kidney. A total of 1083 fish were collected between February 1979 and June 1984 in nine separate sampling periods. Idiopathic lesions, i.e. lesions of unknown cause, were classified into eight hepatic and four renal lesion categories. The significance of certain potential risk factors associated with lesion prevalences, including age, gender, site of capture, season of capture and year of capture, were assessed by logistic regression. The odds ratios for the significant risk factors were also calculated. Site of capture and age of the examined fish were found to be the most important factors for most of the observed lesion types, e.g., hepatic neoplasms and foci of cellular alteration, whereas year and season of capture were significant influences for only a few lesion types, e.g., specific and nonspecific degenerative/necrotic lesions of the liver. Gender of examined fish was not found to be a significant factor for any of the lesion types. These results emphasize the importance of including certain potential influences, such as age and season of capture, in the analysis of field-collected organ pathology data.