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Biomedical subjects

David Guggisberg

Publications and source records attributed to David Guggisberg.

5 recordsLinked to original sources
PubMed2004

Skin markers of occult spinal dysraphism in children: a review of 54 cases.

OBJECTIVES: To verify the diagnostic value of lumbosacral midline cutaneous lesions in asymptomatic children to detect occult spinal dysraphism (OSD) and to propose a practical approach for clinical investigations with respect to the type of cutaneous lesions observed. DESIGN: Retrospective study of 54 children referred to the Department of Pediatric Dermatology between 1990 and 1999 for congenital midline lumbosacral cutaneous lesions. SETTING: The private or institutional practices of participating dermatologists and pediatricians. MAIN OUTCOME MEASURES: Evaluation of the diagnostic value of midline cutaneous lesions for the detec-tion of OSD. Association of skin examination findings with spinal anomalies detected by magnetic resonance imaging or ultrasound. RESULTS: Occult spinal dysraphism was detected in 3 of 36 patients with an isolated congenital midline lesion and 11 of 18 patients with a combination of 2 or more different skin lesions. CONCLUSIONS: A combination of 2 or more congenital midline skin lesions is the strongest marker of OSD. Careful dermatologic examination is needed to detect suggestive markers and request a spinal magnetic resonance image, which is the most sensitive radiologic approach to detect an OSD.

Adolescent↗
PubMed2003

Detection of micrometastases in sentinel lymph nodes from melanoma patients: direct comparison of multimarker molecular and immunopathological methods.

The technique of sentinel lymph node (SLN) dissection is a reliable predictor of metastatic disease in the lymphatic basin draining the primary melanoma. Reverse transcription-polymerase chain reaction (RT-PCR) is emerging as a highly sensitive technique to detect micrometastases in SLNs, but its specificity has been questioned. A prospective SLN study in melanoma patients was undertaken to compare in detail immunopathological versus molecular detection methods. Sentinel lymphadenectomy was performed on 57 patients, with a total of 71 SLNs analysed. SLNs were cut in slices, which were alternatively subjected to parallel multimarker analysis by microscopy (haematoxylin and eosin and immunohistochemistry for HMB-45, S100, tyrosinase and Melan-A/MART-1) and RT-PCR (for tyrosinase and Melan-A/MART-1). Metastases were detected by both methods in 23% of the SLNs (28% of the patients). The combined use of Melan-A/MART-1 and tyrosinase amplification increased the sensitivity of PCR detection of microscopically proven micrometastases. Of the 55 immunopathologically negative SLNs, 25 were found to be positive on RT-PCR. Notably, eight of these SLNs contained naevi, all of which were positive for tyrosinase and/or Melan-A/MART-1, as detected at both mRNA and protein level. The remaining 41% of the SLNs were negative on both immunohistochemistry and RT-PCR. Analysis of a series of adjacent non-SLNs by RT-PCR confirmed the concept of orderly progression of metastasis. Clinical follow-up showed disease recurrence in 12% of the RT-PCR-positive immunopathology-negative SLNs, indicating that even an extensive immunohistochemical analysis may underestimate the presence of micrometastases. However, molecular analyses, albeit more sensitive, need to be further improved in order to attain acceptable specificity before they can be applied diagnostically.

Biomarkers, Tumor↗
PubMed2002

Validation of segmentation techniques for digital dermoscopy.

PURPOSE: This study aims at evaluating two automatic contour detection techniques especially developed for dermoscopic images. METHODS: Twenty-five images of lesions with a fuzzy boundary have been randomly selected. Five dermatologists experienced in dermoscopy have manually drawn the border of all the lesions and repeated the procedure after two and four weeks. The ability of a dermatologist to reproduce its own results was evaluated by measuring the non-overlapping area enclosed by its three successive contours. The interobserver variability evaluated the contour accuracy when using automatic or manual drawings. The mean probability that a pixel has been misclassified was computed for every observer and automatic technique. RESULTS: Experts in dermoscopy are not able to reproduce measurements precisely and the two automatic techniques had a lower misclassification probability than those obtained by each dermatologist. CONCLUSION: This study demonstrates that a single dermatologist should not be used as a reference, and subjective validation of lesion contour is inaccurate outside an experts's group. It is argued that image processing techniques for computer-aided diagnosis must show the best compromise within such a group.

Algorithms↗