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Martin Oberholzer

Publications and source records attributed to Martin Oberholzer.

9 recordsLinked to original sources
PubMed2006

Extraction of high-integrity RNA suitable for microarray gene expression analysis from long-term stored human thyroid tissues.

INTRODUCTION: Isolation of high-quality RNA from fresh-frozen thyroid tissues stored for more than a decade would open novel options for gene expression profiling. Herein, we describe successful extraction of high-integrity RNA from human thyroid tissues that were stored for more than a decade. METHODS: Seventy-nine samples (15 goitres, 20 follicular adenomas, 30 papillary carcinomas, 14 follicular carcinomas) that were shock-frozen in isopentane and stored for a median of 11 years (range 1-16 years) were processed using standard precipitation and column filtration techniques. RNA integrity was assessed by electrophoresis using the RNA integrity number (RIN) algorithm and by gene expression profiling determining the 3'/5' ratio of the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene and the percentage of transcripts detected on the Affymetrix U133 2.0 human genome GeneChip. RESULTS: The median RNA yield was 1.9 microg/mg tissue (papillary carcinoma 2.1 microg/mg, range 0.2-7.2 microg/mg; follicular carcinoma 2.4 microg/mg, range 0.2-3.2 microg/mg; goitre 1.4 microg/mg, range 0.1-5.4 microg/mg; follicular adenoma 1.6 microg/mg, range 0.1-6.2 microg/mg; p = 0.46) with an 8.6 (7.3-9.8) median RIN. The median GAPDH gene 3'/5' ratio was 1.43 (1.34-1.52) and the median percentage of present calls was 48.1% (42.7-52.0%). CONCLUSIONS: Age and entity independent RNA suitable for expression profiling can be extracted from long-term stored fresh-frozen human thyroid tissues.

Adenocarcinoma, Follicular↗
PubMed2006

Potential predictive patterns of minimal residual disease detected by immunohistochemistry on bone marrow biopsy specimens during a long-term follow-up in patients treated with cladribine for hairy cell leukemia.

CONTEXT: Minimal residual disease (MRD) in patients treated for hairy cell (HC) leukemia as assessed by immunohistochemistry has not been included routinely in evaluation of treatment results. OBJECTIVE: To assess the presence of persistent HCs after treatment, as detected by immunohistochemistry, and to evaluate the correlation between the level of MRD and clinical outcome. DESIGN: Percentages of DBA.44-positive HCs were assessed on 116 biopsy specimens from 17 patients. The patients had a median follow-up of 55.4 months. RESULTS: Minimal residual disease was seen in 3 patterns. Group 1 (7 patients) had MRD levels ranging from "rare scattered suspicious HCs" to less than 1%. The MRD levels were stable throughout follow-up, and all patients remained in complete remission. Group 2 (6 patients) had MRD levels ranging from 1% to 5%, and 3 patients were in complete remission at 77.9, 63.8, and 108.0 months. Another patient showed evidence of disease activity (partial remission) at 47.6 months. Two other patients relapsed at 12.3 months and at 25.7 months, respectively, with greater than 1% HCs. Group 3 (4 patients) had MRD levels greater than 5%. Three patients relapsed at 11.3, 12.1, and 29.6 months, respectively, with greater than 5% HCs. The fourth patient had MRD levels of 5% at 14.6 months and 2% at 20.0 months but was subsequently lost to follow-up. CONCLUSIONS: Quantitative assessment of MRD may be of value in identifying patients at risk for relapse of hairy cell leukemia.

Antineoplastic Agents↗
PubMed2005

The iPath telemedicine platform.

An early, point-to-point telepathology system at the University of Basel developed into an open-source, Internet-based platform for telemedicine in 2001. The Internet Pathology Suite (iPath) is a Web-based telepathology platform that permits the online presentation and discussion of cases within user groups. It also allows realtime telemicroscopy across firewalls. After four years, the telepathology network has over 700 active users. More than 6,300 cases with a total of about 39,000 images have been diagnosed. The diagnostic workload of all these cases is not exclusively handled by the Department of Pathology in Basel, but by a growing number of independent groups who also use the server simply as a case repository. What started as a small project for hospitals in Switzerland has become a global network.

Communication↗
PubMed2004

Diagnostic telepathology: long-term experience of a single institution.

OBJECTIVES: The paper reviews the development of the application of telepathology in a department of surgical pathology between 1991 and 2003. The goal of the efforts during this time was to give up the concept of programming a single application, available only between two fixed workstations with sophisticated devices and special software, and to find the virtual "largest common denominator" for implementing as many different applications as possible with the same basic system. METHODS: A new telepathology system was designed as a client-server system with a relational database at its centre. The clients interact together by transferring the questions (texts and images) to a record (case) in the database on the server and by transferring the answers to the same record on the database. RESULTS: The new "open" telepathology system iPath (http://telepath.patho.unibas.ch) has been very well accepted by many groups around the world. The main application fields are: consultations between pathologists and medical institutions without a pathologist (e.g. for frozen section diagnoses or for surgical diagnoses in hospitals in South Asia or Africa), tumour boards, field studies and distance education (http://teleteach.patho.unibas.ch). CONCLUSIONS: Having observed that with iPath we have succeeded in satisfying all our telepathology needs, we are inclined to put the emphasis on the nature of the tasks being performed, as opposed to the methods or technical means for performing a given task. The three organisation models proposed by Weinstein et al. (2001) can be reduced to only two models: the model of discussion groups and the model of expert groups (virtual institutes).

Global Health↗
PubMed2004

Macrofollicular variant of papillary carcinoma of the thyroid: a histologic, cytologic, and immunohistochemical study of 3 cases and review of the literature.

CONTEXT: The macrofollicular variant of papillary carcinoma of the thyroid is a rare entity described by J. Albores-Saavedra and colleagues in 1991. It is characterized histologically by a predominance of macrofollicles and clinically by a low incidence of metastasis. This entity may represent a source of diagnostic error, since it can be easily misinterpreted as a macrofollicular adenoma or nodular goiter. DESIGN: In this study, we describe 3 cases of papillary carcinoma of the thyroid with a macrofollicular growth pattern and review the literature. RESULTS: The fine-needle aspiration biopsies in 2 cases showed large cells with optically clear nuclei and nuclear grooves, suggestive of papillary carcinoma of the thyroid. In one case, the cytology showed no signs of malignancy. In all cases, the tumors showed a combination of the conventional follicular variant of papillary carcinoma of the thyroid and macrofollicles (diameter, >250 microm) occupying more than 50% of the cross-sectional area. Cytologic features were large, cuboidal cells with optically clear, ground-glass nuclei with smooth outlines, a fine chromatin pattern, nuclear grooves, and pseudoinclusions. The colloid was dense and more eosinophilic than in adjacent normal follicles. In 2 cases, there was capsular or blood vessel infiltration, and one tumor had metastasized to a cervical lymph node. One tumor recurred 1 year later as an anaplastic carcinoma. Immunohistochemical staining showed a positivity of the tumor cells for cytokeratins 7, 17, and 19, thyroid transcription factor-1, and galectin-3 and a negativity for cytokeratin 20 and p53. CONCLUSIONS: Although it has been suggested that this tumor is a highly differentiated variant with a favorable prognosis, our study shows that its biologic behavior is not conclusive because metastases and recurrences with dedifferentiation may occur.

Adult↗
PubMed2003

In vivo efficacy of bone-marrow-coated polycaprolactone scaffolds for the reconstruction of orbital defects in the pig.

Alloplastic materials offer a number of advantages over bone autografts in the reconstruction of craniofacial defects. These include: lack of donor site morbidity, unlimited quantities of available material, and the possibility to conform exactly to the defect. An ideal bioresorbable material would degrade slowly, and have osteoconductive properties to allow replacement and remodeling by osseous tissue. This is seldom observed, the materials instead being replaced by fibrous tissue. Polycaprolactone (PCL), an FDA-approved bioresorbable polymer, has several properties that might make it suitable for reconstruction of craniofacial defects. The technique of fused deposition modeling (FDM) allows for the fabrication of highly reproducible bioresorbable 3D scaffolds. The nature of the fully interconnected pore network might enhance vascular ingrowth and osteoconductive properties. It was hypothesized that coating the scaffolds in bone marrow might enhance bone formation due to the osteoinductive nature of the bone-marrow mesenchymal cells. This study aimed to test these hypotheses in the pig model. Defects measuring 2 x 2 cm were surgically created in each orbit of eight Yorkshire pigs. The orbits were divided into three groups: Group 1 (n=4), no reconstruction (control); Group 2 (n=6), reconstruction with no coated PCL scaffolds; and Group 3 (n=6) reconstruction with bone-marrow-coated PCL scaffolds. The results were evaluated at 3 months by histological and histomorphometric analyses. The defects in Group 1 were covered with fibrous scar tissue. The shape of the reconstructed area was insufficient. The defects in Groups 2 and 3 were reconstructed correctly. In Group 2 the noncoated scaffolds showed 4.5% of new bone formation compared with 14.1% in Group 3, which is statistically significant (p<0.05). The entirely interconnected 3D polycaprolactone scaffold seems to be a promising material. It induces the bone ingrowth required for reconstructing craniofacial and orbital defects. Further long-term evaluations of these PCL scaffolds must be made in order to confirm these conclusions.

Absorbable Implants↗
PubMed2002

DNA image cytometry and fluorescence in situ hybridization for noninvasive detection of urothelial tumors in voided urine.

BACKGROUND: Cystoscopy and histologic examination remain the standard methods for initial tumor diagnosis and monitoring for early detection of recurrences, since the sensitivity of conventional urinary cytology for the detection of urothelial tumors in urinary specimens is low. DNA image cytometry (ICM) and fluorescence in situ hybridization (FISH) have been suggested as ancillary tools. The goal of the current study was to compare the diagnostic value of DNA image cytometry and FISH for the noninvasive detection of urothelial tumors in voided urine. METHODS: Cytospin preparations were prepared from voided urine collected prior to the resection of 26 noninvasive (pTa) and 11 invasive (pT1-2) tumors. Specimens from 14 patients with benign prostatic hyperplasia were used as negative controls. DNA ICM was performed using the AUTOCYTE trade mark cell analytical system on Feulgen-stained cytospin specimens. The commercially available UroVysion trade mark FISH multiprobe was used to analyze chromosomes 3, 7, and 17, and 9p21. RESULTS: The overall sensitivity of cytology improved from 24% to 54% and to 78% if supplemented by ICM or FISH, respectively. Image cytometry detected all invasive tumors (pT1-2), while FISH missed one; FISH identified 19 of 26 (73%) pTa tumors, while only 9 (35%) of these tumors were aneuploid by ICM. The results of ICM and FISH were concordant in 37 of 51 (72%) cases. CONCLUSIONS: The current study shows that both FISH and ICM can successfully be used as supplementary methods to detect the clinically most relevant group of invasive bladder carcinomas. However, UroVysion FISH is more sensitive in the detection of pTa tumors than ICM, as it recognizes individual chromosomal alterations that frequently prevail in urothelial tumors.

Carcinoma, Transitional Cell↗