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Biomedical subjects

H Pösl

Publications and source records attributed to H Pösl.

12 recordsLinked to original sources
PubMed2000

Diagnosis of papillary thyroid carcinoma is facilitated by using an RT-PCR approach on laser-microdissected archival material to detect RET oncogene activation.

OBJECTIVE: The purpose of this study was to investigate the value of the expression of the RET oncogene (rearranged during transfection) in papillary thyroid carcinomas (PTC) and its variants in the differential diagnosis of thyroid neoplasias. According to the literature RET oncogene activation by chromosomal rearrangements has been exclusively implicated in PTCs. METHODS: To establish the incidence of RET activation in PTCs we used 5- to 10-microm sections from archival paraffin blocks. Either parts of the tissue slices were manually dissected or a few distinct cells were microdissected by laser-mediated manipulation with the Robot-MicroBeam system. RNA was extracted from paraffin-embedded thyroid tumors and the corresponding normal tissue. RT and nested PCR were performed using primers for RET/PTC1, PTC2 and PTC3, or for RET exons 12 and 13. PCR products were resolved by gel electrophoresis. RESULTS: We detected RET transcription in approximately 85% of the PTCs including follicular variants and in isolated cells of the same tissues, but not in nonmalignant thyroid tissue. CONCLUSIONS: Our method may serve as an additional diagnostic tool to characterize ambiguous neoplasias and to identify especially nonpapillary, i.e. follicular tumors, as papillary carcinomas. Additionally, this study has demonstrated that expressed genes can be analyzed from routine histopathological tissue slides or pooled single cells. Large retrospective studies can also be performed with this method.

Adult↗
PubMed1999

Laser microdissection and laser pressure catapulting for the generation of chromosome-specific paint probes.

Chromosome-specific paint probes provide a powerful tool with wide applications in cytogenetic analysis. Here, we present a new approach using UV-laser microbeam microdissection in combination with laser-pressure catapulting, which allows the fast isolation of single chromosomes for the generation of chromosome-specific paint probes. To demonstrate the feasibility of this approach, single chromosomes were collected and amplified with degenerate oligonucleotide-primed PCR, hapten-labeled and hybridized onto normal metaphase spreads. Fluorescence in situ hybridization signals revealed specific painting of the respective chromosomes.

Animals↗
PubMed1998

Laser micromanipulation systems as universal tools in cellular and molecular biology and in medicine.

The UV-laser microbeam has been established as a valuable tool in a wide area of molecular biology as well as in medical research and applications. This system allows to cut or fuse microscopically small specimen. An important application of the cutting laser is laser microbeam microdissection (LMM) combined with laser pressure catapulting (LPC), which allows to procure single cells or small homogeneous cell areas for subsequent molecular analysis in an entirely "non-contact" manner. With LMM minute tissue areas, single cells or chromosomes are microdissected and separated from their surroundings. Subsequently, LPC ejects the dissectates directly into the cap of a sample tube without any mechanical contact. This enables the rapid procurement of homogeneous specimen from less than one up to several hundreds of micrometers in diameter without encroachment of the adjacent region. The mRNA information of the selected specimen as well as of the remaining probe are well preserved, as demonstrated with laser isolated samples from a routinely prepared tissue section of a differentiated colorectal adenocarcinoma. Reverse transcription of specific mRNA coding for cytoplasmic beta-actin and subsequent hemi-nested PCR amplification was not impaired. Any kind of tissue, as well as single cells from different sources and even subcellular structures can be captured using this laser method. Wherever homogeneous samples are required to analyze cell or chromosome-specific genetic alterations such as in cancer research or prenatal diagnosis this unique and rapid laser micropreparation method will become a key technology of great value.

Adenocarcinoma↗
PubMed1997

Cut out or poke in--the key to the world of single genes: laser micromanipulation as a valuable tool on the look-out for the origin of disease.

The optical micromanipulation systems UV(ultraviolet)-Laser Microbeam and Optical Tweezers Trap, already proven to be powerful tools for 'non-contact' micro-manipulation of gametes, cells and organelles, have now made their way into the nanocosmos of genes and molecules. Force measurements of DNA transcription have been performed and selective DNA molecule micromanipulation gives insight into single molecule behaviour. Retrievement of selected single cells without contamination is an import prerequisite for further processing with modern methods of molecular biology. Laser micro-dissection allows to precisely eliminate any unwanted material or to isolate pieces of chromosomes or single cells of interest with high accuracy and efficiency. This enables the cell or chromosome specific molecular analysis of genes and genetic defects underlying disease, such as cancer or infection. This review article gives an overview of current topics of laser microbeam application in biological or medical research and advanced molecular diagnosis.

Animals↗
PubMed1985

[Endoscopic laser therapy].

The Nd-YAG-laser is being used since ten years in gastroenterological endoscopy with good success. It can be used for treatment of bleeding lesions or lesions which potentially could bleed, for treatment of benign and malignant tumors, treatment of non-neoplastic stenoses and pathological changes in the region of the papilla. Own results with this treatment in 1033 patients are reported, demonstrating high efficacy of this method by improving quality of life and decreasing the number of surgical interventions necessary and also decreasing hospital lethality.

Ampulla of Vater↗
PubMed1981

[Ultrasonography in the diagnosis of fatty liver (author's transl)].

Diagnostic relevance of ultrasonography was studied prospectively and controlled by peritoneoscopy and biopsy. 310 cases were investigated, 126 of these had fatty infiltration of the liver between 5% and 95%, which was diagnosed correctly in 92% of the cases by ultrasonography on the basis of increased reflexes. The incidence of correct diagnoses was 95% resp. 100% in cases with more than 10% resp. 50% fatty infiltration of the liver. Thus, diagnosis of fatty liver can be achieved with high sensitivity (fat infiltration of more than 10% may be recognized) and high specificity (only 4.35% false positives) by ultrasonography. Ultrasonography is a simple, non-invasive, and fast method suited for screening and follow-up in this condition.

Adult↗
PubMed1981

[The neodym-yag-laser: an effective instrument for stopping gastrointestinal bleeding (author's transl)].

Fotocoagulation was performed during 291 emergency endoscopies, mostly in the upper gastrointestinal tract with a neodym-yag-laser from Nov. 1st '78 to Okt. 30th '80; 324 sources of bleeding could be localized in the cases mentioned. Under optimal conditions an immediate stop of bleeding could be achieved in 99% by this procedure. In 27% of cases of upper gastrointestinal bleeding relapses occurred within 4 weeks after fotocoagulation, but only a few of these cases bled from areas coagulated before. Therefore it can be said, that neodym-yag-laser is a very effective instrument in stopping lifethreatening gastrointestinal bleeding, especially if the new transmission system is used (quartzmonofiber with coaxial CO2-jet-stream).

Esophageal and Gastric Varices↗
PubMed1979

[The uni-quatro camera - a new camera for documentation of monitor pictures (author's transl)].

A new camera system is described, which was devised to take pictures of monitor screens on special X-ray film, and it is compared with conventional methods of documentation. Quality of pictures obtained with this method is optimal, handling is quick and simple, and, in spite of that, the camera is smaller and less expensive than other multiformate cameras. Polaroid, special X-ray films and other films may be used interchangeable for all sorts of monitor screens. A report is given about the routine use of this system in ultrasonography.

Documentation↗
PubMed1979

[Endoscopic polypectomy in the colon, a calculated risk (author's transl)].

5774 colonoscopies were performed in 5 years, --including 2877 total colonoscopies and 1338 polypectomies. This confirms the diagnostic and therapeutic value of this method. Increasing experience of the endoscopist, better techniques as well as adequate pre-and postoperative care contribute to decreasing the risk of the polypectomy. If coagulation current is used exclusively the risk of bleeding can be lowered considerably.

Colonic Neoplasms↗
PubMed1978

[Complete colonoscopy with short instruments--results obtained with the ACMI F9S (author's transl)].

Total colonoscopy was performed in 3,740 cases within approximately 4 years. Results show, that total colonoscopy may be used as a primary method of clinical examination in an optimal way, if the technically improved, new class of instruments is used. The new short ACMI F6S is especially suited for this approach, yielding reliable results in about 92% of all patients, if the colon is clean and if there are no organic stenoses present.

Colitis, Ulcerative↗