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Biomedical subjects

H Leonhardt

Publications and source records attributed to H Leonhardt.

At least 181 records · Page 10Linked to original sources
PubMedDate not supplied

Mammalian DNA methyltransferases show different subnuclear distributions.

In mammalian cells, DNA methylation patterns are precisely maintained after DNA replication with defined changes occurring during development. The major DNA methyltransferase (Dnmt1) is associated with nuclear replication sites during S-phase, which is consistent with a role in maintenance methylation. The subcellular distribution of the recently discovered de novo DNA methyltransferases, Dnmt3a and Dnmt3b, was investigated by immunofluorescence and by epitope tagging. We now show that both Dnmt3a and Dnmt3b are distributed throughout the nucleoplasm but are not associated with nuclear DNA replication sites during S-phase. These results suggest that de novo methylation by Dnmt3a and Dnmt3b occurs independently of the replication process and might involve an alternative mechanism for accessing the target DNA. The different subcellular distribution of mammalian DNA methyltransferases might thus contribute to the regulation of DNA methylation.

Animals↗
PubMedDate not supplied

[Out-patient palliative care of children with cancer and their families].

Pediatric palliative care is still in its beginning. Most children with life-threatening disorders succumb with incomplete symptom control under in-patient conditions. Due to the limited number of patients and large hospital-home distances the realization of out-patient concepts of palliative care especially for children and adolescents with cancer is purposeful and beneficial. In a pilot project such an a aforementioned concept of pediatric palliative care proved successfully working despite insufficient conditions. Guidelines of pediatric palliative care are to be defined at short notice in order to ascertain autonomy and mobility of patients aiming at highest possible quality of life. The recently initiated program of integrating ambulatory and in-patient care within the regulations set forth in Germany's last health care system reform offers the chance of palliative home care of children in their terminal phase of life.

Adolescent↗
PubMedDate not supplied

Identification and characterization of novel smoothelin isoforms in vascular smooth muscle.

Smoothelin is a cytoskeletal protein specifically expressed in differentiated smooth muscle cells and has been shown to colocalize with smooth muscle alpha actin. In addition to the small smoothelin isoform of 59 kD, we recently identified a large smoothelin isoform of 117 kD. The aim of this study was to identify and characterize novel smoothelin isoforms. The genomic structure and sequence of the smoothelin gene were determined by genomic PCR, RT-PCR and DNA sequencing. Comparison of the cDNA and genomic sequences shows that the small smoothelin isoform is generated by transcription initiation 10 kb downstream of the start site of the large isoform. In addition to the known smoothelin cDNA (c1 isoform) we identified two novel cDNA variants (c2 and c3 isoform) that are generated by alternative splicing within a region, which shows similarity to the spectrin family of F-actin cross-linking proteins. Visceral organs express the c1 form, while the c2 form prevails in well-vascularized tissue as analyzed by RT-PCR. We then generated specific antibodies against the major smoothelin isoforms and could show by Western blotting and immunohistochemistry that the large isoform is specifically expressed in vascular smooth muscle cells, while the small isoform is abundant in visceral smooth muscle. These results strongly suggest that the smoothelin gene contains a vascular and a visceral smooth muscle promoter. The cell-type-specific expression of smoothelin isoforms that are associated with actin filaments may play a role in the modulation of the contractile properties of different smooth muscle cell types.

Alternative Splicing↗