Biomedical subjects

A Ost

Publications and source records attributed to A Ost.

113 records · Page 7Linked to original sources

PubMedDate not supplied

Age- and site-dependent cell cycle composition of the normal human colonic mucosa.

BACKGROUND AND AIM: As a reference to studies of DNA-ploidy and S- and G2/M-phase fractions in patients with inflammatory bowel diseases, we describe the mucosa of normal individuals with respect to age and localization in the colon. MATERIALS AND METHODS: One hundred and sixty-five biopsies from the right, transverse and left colon from 44 subjects (20 men, 24 females, median age 55 years (range 21-80)) who were referred for colonoscopy due to rectal bleeding, diarrhoea or suspicion of neoplasia, but with normal macroscopic and microscopic findings, were analysed by DNA-flow cytometry for ploidy and cell cycle composition. The biopsies were immediately fixed in buffered formalin and then analysed by a method for high quality preparations of cell nuclei without any centrifugation steps, resulting in minimal cell damage and low frequencies of aggregates, making the background levels low in the DNA-histograms. RESULTS: The median S-phase fraction of the biopsies, all diploid, was 2.35% (0.1-8.3). The S-phase fraction increased linearly with age (p = 0.001) and decreased from the right colon (median 2.75% (0.5-8.3)) over the transverse colon (median 2.3% (0.1-6.2)) to the left colon (median 1.9% (0.8-6.5), p < 0.02). The fraction of G2-cells (median 1.1%, range 0.2-5.1) increased significantly with increased S-phase fraction (p < 0.0001). CONCLUSION: DNA-FCM analyses of normal colonic tissue demonstrate an age- and site-dependent variation with regard to cell proliferation. This variation has to be taken into consideration when biopsy specimens from chronic colitis mucosa are evaluated.

Adult↗

PubMedDate not supplied

Colorectal cancer in colonic Crohn's disease--high frequency of DNA-aneuploidy.

BACKGROUND: The risk of colorectal cancer (CRC) in colonic Crohn's disease (CCD) seems to be of the same magnitude as in extensive, longstanding ulcerative colitis (UC) and colonoscopic surveillance has been advocated. Mucosal dysplasia and DNA-aneuploidy are early warning markers of malignant transformation in UC. Data concerning the occurrence of such premalignant lesions in CCD are scarce. AIMS: The objective of this study was to investigate the DNA ploidy pattern in CCD-patients with manifest CRC, both in the tumour, as well as in the adjacent and distant colorectal mucosa. The results from DNA-flow cytometry analyses (FCM) prior to the development of a CRC in CCD were also investigated. MATERIALS AND METHODS: Biopsies obtained at colonoscopy and surgical specimens from 43 patients with colonic or ileocolonic CD developing CRC between 1988 and 1998 were reviewed. The CRC histological phenotype, and the occurrence of dysplasia were registered. CRC-tissue and tissue from areas with dysplasia adjacent to and/or distant from the tumour were obtained from paraffin-embedded blocks and were analysed by FCM after preparation. RESULTS: Twenty-four CRCs in 21 patients (14 men) were suitable for FCM-analyses. The median age at CRC-diagnosis was 53 years (21-73) and the median CCD-duration was 14.5 years (1-50). A predominance of CRC was found either in the cecum (9124) or in the rectum (7/24). DNA-aneuploidy was found in 62.5% (15/24) of the tumours, in 25% (2/8) in adjacent and/or distant mucosa, and in 50% (2/4) of the patients that had been subjected to colonoscopic surveillance prior to the CRC-diagnosis. In 7patients (29%), definite dysplasia was detected adjacent to andlor distant from the tumour. Of the 6 patients undergoing colonoscopic surveillance, 3 (50%) displayed definite dysplasia prior to the colectomy. CONCLUSION: Since DNA- aneuploidy is a' common feature in CRCs in CCD and precede the development of invasive carcinoma, inclusion of FCM-analyses of colorectal biopsies may enhance the sensitivity of identifying high-risk CCD-patients prone to develop CRC within the frame of colonoscopic surveillance programs.

Adult↗

PubMedDate not supplied

Fine needle aspiration cytology and immunocytochemistry of large cell lymphomas expressing the Ki-1 antigen.

Cytomorphology and immunocytochemistry were used to diagnose two cases of large cell anaplastic lymphomas that expressed the Ki-1 antigen. Smears stained with the May-Grünwald-Giemsa stain showed a cytomorphologic spectrum that varied from immunoblastlike cells to large tumor cells with pleomorphic nuclei. The tumor cells had a distinct basophilic cytoplasm, which often contained vacuoles. Giant cells with wreathlike multilobulated bizarre nuclei were also observed. Immunocytochemistry on a cytocentrifuged specimen showed that the tumor cells were of a T-helper phenotype; all strongly expressed the Ki-1 antigen and receptors for HLA-DR and IL-2.

Adolescent↗

PubMedDate not supplied

Maturation asynchrony in leukemic cells. An abnormal combination of normal cell markers.

Multiple monoclonal antibodies and enzyme assays were used to study maturity markers (myelo-peroxidase) and immaturity markers (terminal transferase, HLA-2) in acute myeloid leukemia cells from 35 patients. In 8 of the patients, indications were found of an expression of maturity and immaturity markers on the same cells, here in called maturation asynchrony. It is suggested that the orderly appearance and disappearance of markers during the maturation of normal cells is disordered in malignant cells, and that single markers should be used with caution for the maturation classification of tumors. The simultaneous expression of maturity and immaturity marker by tumor cells could explain also why such cells can be recognized as abnormal even in the absence of tumor specific antigens.

Antibodies, Monoclonal↗

PubMedDate not supplied

Detection of TdT in AML blasts by immunological and biochemical techniques.

The cellular level of terminal deoxynucleotidyl transferase (TdT) was measured in blasts from patients with AML. Parallel determinations were made using an immunoassay and polymerizing reaction. There was a good correlation between the two techniques (r = 0.92) and detectable levels of the enzyme was found in approximately 50% of the cases. The TdT levels found in AML blasts were 1/10 - 1/100 of that reported for cells of lymphoid origin.

DNA Nucleotidylexotransferase↗