Abdominal Aortic Aneurysm Diameters: A Study on the Discrepancy between Inner to Inner and Outer to Outer Measurements.

INTRODUCTION: The NHS Abdominal Aortic Aneurysm Screening Programme (NAAASP) uses the maximal anterior to posterior (AP) inner-to-inner (ITI) wall diameter in sizing aortic dimensions when screening with ultrasound. It is recognised that ITI measurements are smaller than outer-to-outer (OTO) measurements, and the primary aim was to calculate the absolute difference in AP ITI and OTO measurements across varying aortic diameters. The secondary aim was to estimate the potential number of patients lost from the screening programme. METHODS: Since April 2012, patients outside the screening programme that undergo ultrasound of abdominal aortas have their ITI and OTO measurements recorded. These measurements were compared retrospectively and analysed for variability at threshold sizes of AAAs. RESULTS: From May 2012 to October 2013, 452 abdominal aortic ultransound scans recorded both ITI and OTO measurements. The majority (81%) were performed on men with the mean age of 78 years. The mean difference between ITI and OTO measurements was 4.21 mm (p < .001). There was no difference between the genders. Thresholds were created for analysis between different ITI and OTO aortic diameters; these were <3 cm, 3.1-4 cm, 4.1-5 cm, and >5 cm. There was no significant difference between the means at each threshold size for ITI diameter (p = .758). In the first 2 years from April 2012, 15,447 men underwent screening.Of these, 177 (1.14%) had sub-threshold ITI aortic diameters between 2.6 cm and 2.9 cm. This would upscale to 5,316 men nationally. CONCLUSION: We have demonstrated a consistent and significant 4mm difference between ITI and OTO diameters in live scanning. Lowering the threshold for entry into a surveillance AAAs to an ITI diameter of 26mm rather than the current 30 mm is advocated. An alternative cost-effective way is to rescreen this small sub-group at 5 or 7 years.

Expression of c-fos in the main olfactory bulb of neonatal rabbits in response to garlic as a novel and conditioned odour.

Expression of c-Fos was examined in the olfactory bulbs of 3-day-old rabbits after they had been presented with the odour of garlic as a novel stimulus, as a learned odour, or during conditioning, and this expression compared with baseline levels in non-stimulated controls. Exposure to garlic odour resulted in substantial and widespread increases in c-Fos expression in the olfactory bulbs of all animals. However, although conditioned pups showed a specific behavioural response to the learned garlic odour, neither the amount nor pattern of c-Fos expression differed compared to pups exposed to garlic as a novel odour. The odour-induced expression of c-Fos was not well localised, although there was a significant increase in the number of granule cells expressing c-Fos in the ventrolateral region of the bulb. These results support previous reports that the response to odours in the olfactory bulb of new-born animals is not as spatially distinct as that in adults. Nevertheless, the immature olfactory system of these young animals is clearly capable of very specific odour learning.

Endogenous expression of C-Fos in hypothalamic nuclei of neonatal rabbits coincides with their circadian pattern of suckling-associated arousal.

Rabbits exhibit an unusually restricted form of maternal care. The newborn young are only nursed for about 3 min every 24 h and drink up to one third of their body weight in this time. They show a circadian increase in activity in anticipation of the doe's visit, which is entrained by suckling and appears analogous to feeding-entrained rhythms reported for other species. By investigating the expression of c-Fos protein in nursed and un-nursed pups at selected times before and after scheduled nursing, we were able to distinguish endogenous patterns of neuronal activation and patterns induced by suckling. Increased endogenous expression of c-Fos in the paraventricular thalamus and in the magnocellular neurons of the paraventricular hypothalamus coincided with the period of anticipatory arousal. By contrast, suckling induced c-Fos expression in the supraoptic nucleus and the parvocellular neurons of the paraventricular hypothalamus, whilst decreasing expression in the magnocellular neurons. Furthermore, the endogenous pattern of c-Fos expression was less distinct in 3-day-old compared to 7-day-old pups, suggesting maturational or experience-related influences on the neural correlates of the anticipatory arousal. In conclusion, the close correspondence between c-Fos expression and pups' endogenous rhythm of behaviour suggests that the rabbit's natural schedule of restricted nursing provides an ideal model in which to investigate the ontogeny of circadian function without disrupting the mother-offspring relationship or normal neonatal development.