Prospective comparison of three non-invasive tests for pancreatic disease.

Ultrasonography, computed tomography (CT), and an oral pancreatic function test were evaluated prospectively in 107 consecutive patients suspected of having pancreatic disease, the final diagnosis being made independently of these tests. Seventeen patients proved to have either chronic pancreatitis or a pancreatic neoplasm. Five had an unfused ventral pancreas and 10 had "minimal change" pancreatograms. Seventy five patients did not have pancreatic disease. Among the 17 patients with pancreatic disease the sensitivities of ultrasound, CT, and the pancreatic function test were 70%, 71%, and 76% respectively; among those without disease values of specificity of the three tests were 75%, 87%, and 72%. All three tests failed to detect most of the patients with unfused ventral pancreases or minimal change pancreatograms. The predictive values of a positive result for the three tests were 43%, 67%, and 34%. The predictive value of a negative result was greater than 90% for all the tests. Results improved when CT was combined with either of the two other tests. These findings show that CT is the most accurate of the three tests in diagnosing pancreatic disease but that a combination of ultrasound and the oral pancreatic function test offers a more widely applicable and almost as accurate alternative.     

Automatic system for 3D reconstruction of the chick eye based on digital photographs

The geometry of anatomical specimens is very complex and accurate 3D reconstruction is important for morphological studies, finite element analysis (FEA) and rapid prototyping. Although magnetic resonance imaging, computed tomography and laser scanners can be used for reconstructing biological structures, the cost of the equipment is fairly high and specialised technicians are required to operate the equipment, making such approaches limiting in terms of accessibility. In this paper, a novel automatic system for 3D surface reconstruction of the chick eye from digital photographs of a serially sectioned specimen is presented as a potential cost-effective and practical alternative. The system is designed to allow for automatic detection of the external surface of the chick eye. Automatic alignment of the photographs is performed using a combination of coloured markers and an algorithm based on complex phase order likelihood that is robust to noise and illumination variations. Automatic segmentation of the external boundaries of the eye from the aligned photographs is performed using a novel level-set segmentation approach based on a complex phase order energy functional. The extracted boundaries are sampled to construct a 3D point cloud, and a combination of Delaunay triangulation and subdivision surfaces is employed to construct the final triangular mesh. Experimental results using digital photographs of the chick eye show that the proposed system is capable of producing accurate 3D reconstructions of the external surface of the eye. The 3D model geometry is similar to a real chick eye and could be used for morphological studies and FEA.     

Collagen-induced arthritis in common marmosets: a new nonhuman primate model for chronic arthritis

Introduction  

There is an ever-increasing need for animal models to evaluate efficacy and safety of new therapeutics in the field of rheumatoid arthritis (RA). Particularly for the early preclinical evaluation of human-specific biologicals targeting the progressive phase of the disease, there is a need for relevant animal models. In response to this requirement we set out to develop a model of collagen-induced arthritis (CIA) in a small-sized nonhuman primate species (300 to 400 g at adult age); that is, the common marmoset (Callithrix jacchus).     

Disentangling the effect of climatic and hydrological predictor variables on benthic macroinvertebrate distributions from predictive models

Hydrobiologia - Lotic freshwater macroinvertebrate species distribution models (SDMs) have been shown to improve when hydrological variables are included. However, most studies to date only include...     

Evolution of normal and neoplastic tissue stem cells: progress after Robert Hooke

The appearance of stem cells coincides with the transition from single-celled organisms to metazoans. Stem cells are capable of self-renewal as well as differentiation. Each tissue is maintained by self-renewing tissue-specific stem cells. The accumulation of mutations that lead to preleukaemia are in the blood-forming stem cell, while the transition to leukaemia stem cells occurs in the clone at a progenitor stage. All leukaemia and cancer cells escape being removed by scavenger macrophages by expressing the ''don''t eat me'' signal CD47. Blocking antibodies to CD47 are therapeutics for all cancers, and are currently being tested in clinical trials in the US and UK.     

Simulated natural day lengths synchronize seasonal rhythms of asynchronously born male Siberian hamsters

Photoperiodism research has relied on static day lengths and abrupt transitions between long and short days to characterize the signals that drive seasonal rhythms. To identify ecologically relevant critical day lengths and to test the extent to which naturally changing day lengths synchronize important developmental events, we monitored nine cohorts of male Siberian hamsters (Phodopus sungorus) born every 2 wk from 4 wk before to 12 wk after the summer solstice in a simulated natural photoperiod (SNP). SNP hamsters born from 4 wk before to 2 wk after the solstice underwent rapid somatic and gonadal growth; among those born 4-6 wk after the solstice, some delayed puberty by many weeks, whereas others manifested early puberty. Hamsters born eight or more weeks after the solstice failed to undergo early testicular development. The transition to delayed development occurred at long day lengths, which induce early puberty when presented as static photoperiods. The first animals to delay puberty may do so predominantly on the basis of postnatal decreases in day length, whereas in later cohorts, a comparison of postnatal day length to gestational day length may contribute to arrested development. Despite differences in timing of birth and timing of puberty, autumn gonadal regression and spring gonadal and somatic growth occurred at similar calendar dates in all cohorts. Incrementally changing photoperiods exert a strong organizing effect on seasonal rhythms by providing hamsters with a richer source of environmental timing cues than are available in simple static day lengths.