Comparison of PCR methods and culture for the detection of Borrelia spp. in patients with erythema migrans

ABSTRACTThe sensitivities of two PCR assays and culture were compared for the detection of Borrelia spp. in skin specimens of 150 patients with typical erythema migrans. In addition, the accuracy of the methods for the identification of Borrelia spp. was compared by analysing culture isolates and material obtained directly from skin biopsy specimens. Borrelia burgdorferi sensu lato was isolated from 73 (49%) of 150 skin biopsy specimens. Using a nested PCR targeting the rrf–rrl region and a PCR targeting the flagellin gene, 107 (71%) and 36 (24%) specimens, respectively, were positive. With both PCRs, positive results were more frequent with culture-positive samples (67/73 (92%) and 24/73 (33%) for the nested and flagellin PCRs, respectively) than with culture-negative samples (40/77 (52%) and 12/77 (16%) for nested and flagellin PCR, respectively). Pulsed-field gel electrophoresis after MluI restriction identified 69/73 (95%) isolates, of which 58/69 (84%) were Borrelia afzelii and 11/69 (16%) were Borrelia garinii. After MseI restriction of PCR products amplified from the intergenic rrf–rrl region, B. afzelii was identified in 73/107 (68%) samples, B. garinii in 22/107 (21%) samples, and both species in 11/107 (10%) samples. The corresponding results for culture-positive specimens were 41/69 (59%), 14/69 (20%), and 7/69 (10%). Comparison of the results for specimens positive according to both approaches revealed complete uniformity in 80% of the cases. Overall, nested PCR was the most sensitive method for the demonstration of Borrelia spp. in erythema migrans skin lesions, followed by culture and PCR targeting the flagellin gene. The congruence of identification results obtained by analyzing culture isolates and material obtained directly from skin biopsies was relatively high but incomplete

Application of infrared thermography in computer aided diagnosis

The invention of thermography, in the 1950s, posed a formidable problem to the research community: What is the relationship between disease and heat radiation captured with Infrared (IR) cameras? The research community responded with a continuous effort to find this crucial relationship. This effort was aided by advances in processing techniques, improved sensitivity and spatial resolution of thermal sensors. However, despite this progress fundamental issues with this imaging modality still remain. The main problem is that the link between disease and heat radiation is complex and in many cases even non-linear. Furthermore, the change in heat radiation as well as the change in radiation pattern, which indicate disease, is minute. On a technical level, this poses high requirements on image capturing and processing. On a more abstract level, these problems lead to inter-observer variability and on an even more abstract level they lead to a lack of trust in this imaging modality. In this review, we adopt the position that these problems can only be solved through a strict application of scientific principles and objective performance assessment. Computing machinery is inherently objective; this helps us to apply scientific principles in a transparent way and to assess the performance results. As a consequence, we aim to promote thermography based Computer-Aided Diagnosis (CAD) systems. Another benefit of CAD systems comes from the fact that the diagnostic accuracy is linked to the capability of the computing machinery and, in general, computers become ever more potent. We predict that a pervasive application of computers and networking technology in medicine will help us to overcome the shortcomings of any single imaging modality and this will pave the way for integrated health care systems which maximize the quality of patient care

On the linear independence of (truncated) hierarchical subdivision splines

Motivated by the necessity to perform adaptive refinement in geometric design and numerical simulation, (truncated) hierarchical generating systems for nested spaces of splinefunctions defined on domains in Rd have been recently introduced. Their linear independence can be guaranteed with the help of the local linear independence of the spline basisat each level. The present paper extends this framework to spline functions that are definedon domain manifolds, in particular focusing on the case of subdivision splines generatedby the Catmull-Clark, Loop, and modified Butterfly subdivision schemes. Since the property of local linear independence is no longer available, we introduce the concept of safesubdomains, which allows us to guarantee linear independence. We provide a catalog ofsafe subdomains that facilitates the design of domain hierarchies with linearly independent(truncated) hierarchical generating systems