Biomedical subjects

M M Ott

Publications and source records attributed to M M Ott.

39 records · Page 3Linked to original sources

PubMed1991

Lymphadenitis and lymphoproliferative lesions associated with the human herpes virus-6 (HHV-6).

A newly described herpes virus, human herpes virus 6, (HHV-6), has been linked to exanthema subitum but beyond this its pathogenetic impact remains to be determined. A large body of evidence links it to various lymphoproliferative disorders and this study was conducted to identify forms of lymphoproliferation linked to HHV-6. We studied biopsy samples from 32 patients with disorders of the lymphatic system for the presence of HHV-6, both by polymerase chain reaction (PCR) and in-situ hybridization (ISH) methods, as well as Epstein-Barr virus (EBV) viral DNA, clonal rearrangements of the antigen receptor genes and bcl-2 genes. All the specimens were studied morphologically and a clinical follow-up of up to 4 years was obtained. Seven of the 32 patients were positive for HHV-6 DNA and the remainder were negative. Two of these HHV-6 positive specimens, both from elderly persons, showed a similar distinct histological pattern diagnosed as malignant B-cell lymphoma of high grade malignancy. Two other HHV-6-positive specimens were reactive lymphadenopathies occurring in younger adults. In addition, one further specimen with evidence of EBV-involvement was from a patient who died 3 months after biopsy with fatal infectious mononucleosis (IM). These five samples had HHV-6 DNA by PCR and ISH. Two specimens without specific histologic abnormalities showed evidence of HHV-6 only by PCR but not by ISH. Both high grade malignant lymphomas showed clonal proliferations, one of monoclonal B-cells and the other of clonal T-cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1991

Chromosomal translocation detected by bcl-1 and bcl-2 rearrangement in low-grade B-cell lymphomas in a European population.

Twenty-nine cases of non-Hodgkin's lymphoma of low-grade malignancy in a European population were investigated for the presence of bcl-2 and bcl-1 gene rearrangement. The cases were classified according to the Kiel classification. It was shown that bcl-2 gene rearrangements were exclusively confined to centroblastic-centrocytic lymphomas. bcl-1 rearrangements were found in two cases of chronic lymphocytic leukaemia. As the chromosomal translocation t(14;18) is reported to occur in up to 85% of follicular lymphomas, our results provide additional evidence that the differentiation of low-grade B-cell lymphomas according to the Kiel classification defines biologically distinct entities.

Chromosomes, Human, Pair 14↗

PubMedDate not supplied

Progesterone receptors are detectable in tumor fragment spheroids of meningiomas in vitro.

Progesterone receptors (PgR) are hardly to be found in monolayer tissue culture of meningiomas although 60-70% of native tissue specimens are PgR positive. Thus we examined whether RgR might be detectable in fragment spheroids of meningiomas in vitro. 25 meningiomas of 17 women and 8 men were investigated as native tissue, monolayer cell culture (primary passage and passage 3) and as fragment spheroid culture after 1 and 3 weeks. 18/25 native tissue samples revealed the PgR. There was no prevalence of sex or histological subtypes discernible. PgR was preserved in cell clumps of the primary passage but was completely lost when cells grew as monolayers (primary passage and passage 3). 21 meningiomas formed spheroids in vitro. In 8 out of 15 native PgR positive tumors the fragment spheroids showed PgR on cryosections after 1 and 3 weeks of culture. We conclude that PgR are preserved in a considerable amount of tumor fragment spheroids of meningiomas in contrast to monolayer culture. Thus spheroids seem to be a suitable tool to investigate progesterone/anti-progesterone effects in meningiomas in vitro.

Culture Techniques↗