Phaeochromocytoma and functioning paraganglioma in childhood and adolescence: role of iodine 131 metaiodobenzylguanidine

Phaeochromocytomas and functioning paragangliomas are rare tumours in childhood and adolescence. We review our experience of 43 cases (24 men, 19 women) who were first diagnosed at the age of ⩽ 18 years. All patients were evaluated at some point in their illness with iodine 131 metaiodobenzylguanidine ( 131 I-mIBG) scintigraphy. Eight patients (19%) had bilateral adrenal tumours, 12 (28%) had solitary extra-adrenal tumours, and 8 (19%) had multiple tumours. In 10 patients (23%), the tumours were associated with a familial neurocristopathic syndrome. Thirteen of 24 (54%) unifocal tumours which were initially considered to be benign ultimately proved to be multi-focal and/or malignant. The final prevalence of malignancy was 60% − 26 patients, of whom only 15 (57%) had obviously malignant tumours at the time of diagnosis. Primary tumour size ⋝5 cm was more commonly associated with a malignant course in adrenal but not extra-adrenal tumours. No other clinical, biochemical or morphological characteristic was significantly associated with malignancy. Although the high prevalence of malignancy in this series at least partly reflects referral bias, the need for lifelong follow-up of these patients is underscored. 131 I-mIBG scintigraphy was positive in 36 patients (84%), with a somewhat lower false-negative rate (12%) than X-ray computed tomography (20%). Eight patients with malignant tumours received therapeutic doses of 131 I-mIBG, with partial tumour responses in 3. Thus, 131 I-mIBG is an efficacious, non-invasive, localising agent and may be considered as a palliative therapeutic agent when alternatives have failed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46831/1/259_2005_Article_BF02262730.pd

A mismatch between signal transmission efficacy and mating success calls into question the function of complex signals

Variation in transmission characteristics of signalling environments is hypothesized to influence the evolution of signalling behaviour, signal form and sensory systems of animals. However, many animals communicate across multiple signalling environments, raising the possibility that some displays have evolved explicitly to enable communication across heterogeneous signalling environments. In the present paper, we explored multiple potential impacts of the signalling environment on courtship displays in the wolf spider Schizocosa retrorsa. Males of this species court females on a range of substrate types using a combination of vibratory and visual signals. Through a series of experiments, we investigated (1) activity patterns and male microhabitat use, (2) component-specific vibratory signal transmission across natural substrate types and (3) copulation success across substrate types and light levels. We found that, in the laboratory, (1) female and male S. retrorsa are most active during daylight hours, and mature males resided and courted most on leaf litter, as compared to their natural habitat types of pine litter or sand; (2) male vibratory courtship signals transmitted best on leaf litter, yet (3) males obtained the highest copulation success on sand, regardless of light level. Our results demonstrate that copulation in S. retrorsa is more likely to occur in environments with suboptimal vibratory signal transmission, irrespective of visual signal transmission. We suggest that these results point to (1) a minor role of bimodal (vibratory and visual) courtship signalling in S. retrorsa, (2) the importance of an additional signalling modality (most likely air particle movement), (3) a role of other substrate-dependent factors (e.g. predation risk), and/or (4) a reversed female preference for vibratory signalling

Regional and local effects on reproductive allocation in epicormic and lignotuberous populations of Banksia menziesii

Reproductive allocation (RA) is a measure of how resources (biomass, nutrients) are partitioned between reproductive structures and the rest of the plant. For plants that resprout after fire, the percentage of resources allocated to reproduction may vary depending on their resprouting ability. Our study examines the percentage RA (biomass, N, P, K) and nutrient content of current season’s growth in southern (Swan Coastal Plain) epicormic and northern (Eneabba Plain) lignotuberous resprouter populations of Banksia menziesii (Proteaceae), a species endemic to nutrient-impoverished sandplains of southwestern Australia. Within each population, plants along road edges were compared with plants not associated with road edges. There was no difference in total nutrient content of current year’s growth between both resprouting types, except that total K in the shoots of lignotuberous populations was >2 times that in the epicormic populations. Non-road lignotuberous plants allocated twice the biomass, N and P, and 13.5 times the K, to reproduction as non-road epicormic plants. Lignotuberous populations had the highest RA (17–34% of biomass, N, P, K), with non-road epicormic populations the lowest RA (3–15%). This can be viewed as an adaptive (ultimate) response to the poorer postfire survival and recruitment conditions where the lignotuberous populations occur.Total biomass and nutrient content of road-edge plants was 2–3 times that of non-edge plants. Lignotuberous populations in both road positions allocated the same fraction of biomass, N and P to reproduction, whereas road-edge populations allocated 10% less K than non-road. Road-edge epicormic populations allocated 5–10% more biomass, N, P and K to reproduction than non-road populations. This can be viewed as an ecophysiological (proximate) response to the better growing conditions created by the roadways that may also ultimately have an adaptive explanation