Biomedical subjects

K Lindfors

Publications and source records attributed to K Lindfors.

8 recordsLinked to original sources

PubMed2006

SAP30L interacts with members of the Sin3A corepressor complex and targets Sin3A to the nucleolus.

Histone acetylation plays a key role in the regulation of gene expression. The chromatin structure and accessibility of genes to transcription factors is regulated by enzymes that acetylate and deacetylate histones. The Sin3A corepressor complex recruits histone deacetylases and in many cases represses transcription. Here, we report that SAP30L, a close homolog of Sin3-associated protein 30 (SAP30), interacts with several components of the Sin3A corepressor complex. We show that it binds to the PAH3/HID (Paired Amphipathic Helix 3/Histone deacetylase Interacting Domain) region of mouse Sin3A with residues 120-140 in the C-terminal part of the protein. We provide evidence that SAP30L induces transcriptional repression, possibly via recruitment of Sin3A and histone deacetylases. Finally, we characterize a functional nucleolar localization signal in SAP30L and show that SAP30L and SAP30 are able to target Sin3A to the nucleolus.

Animals↗

PubMed2004

Detection and spectroscopy of gold nanoparticles using supercontinuum white light confocal microscopy.

We combine confocal microscopy using supercontinuum laser illumination and an interferometric detection technique to identify single nanoparticles of diameter below 10 nm. Spectral analysis of the signal allows us to record the plasmon resonance of a single nanoparticle. Our results hold great promise for fundamental studies of the optical properties of single metal clusters and for their use in biophysical applications.

Journal Article↗

PubMed2002

Blisters in the small intestinal mucosa of coeliac patients contain T cells positive for cyclooxygenase 2.

BACKGROUND AND AIMS: Coeliac disease is characterised by atrophy of the villi and hyperplasia of the crypts in the mucosa of the small intestine. It is caused by an environmental trigger, cereal gluten, which induces infiltration of the mucosa by inflammatory cells. We hypothesised that these inflammatory cells express cyclooxygenase 2 (COX-2), an enzyme that contributes to the synthesis of pro and anti-inflammatory prostaglandins and is known to be expressed at sites of inflammation in the stomach and colon. We have investigated expression of COX-2 in the coeliac disease affected small intestinal mucosa where it may be an indicator of either disease induction or mucosal restoration processes. PATIENTS AND METHODS: Small intestinal biopsy samples from 15 coeliac patients and 15 non-coeliac individuals were stained immunohistochemically for COX-2. Samples from 10 of the patients were also stained after these patients had been on a gluten free diet for 6-24 months. Various cell type marker antigens were used for immunohistochemical identification of the type of cell that expressed COX-2. To further verify colocalisation of the cell type marker and COX-2, double immunoperoxidase and immunofluorescence methods were employed. Immunoelectron microscopy was used to investigate the subcellular location of COX-2. RESULTS: In all samples taken from coeliac patients, clusters of cells with strong immunoreactivity for COX-2 were found in those areas of the lamina propria where the epithelium seemed to blister or was totally detached from the basement membrane. These clusters were reduced in number or totally absent in samples taken after a gluten free diet. No such clusters were seen in any control samples. The density of COX-2 positive cells lining the differentiated epithelium decreased significantly from 13.5 (5.1) cells/10(5) microm(2) (mean (SD)) in the untreated patient samples to 6.5 (2.0) cells/10(5) microm(2) after a gluten free diet (p<0.001), and was 3.3 (1.9) cells/10(5) microm(2) in control samples (p<0.001 compared with untreated or diet treated coeliac samples). Staining for COX-2 was localised to CD3+ T cells and CD68+ macrophages in the mucosal lesions but not all of these cells were positive for COX-2. Immunoelectron microscopy revealed that the ultrastructure of the COX-2 positive cells resembled that of lymphocytes, and the immunoreaction was localised to the rough endoplasmic reticulum and the nuclear envelope. CONCLUSIONS: Our results show that in coeliac disease, blistering of small intestinal epithelial cells is associated with accumulation of COX-2 positive T cells, and the number of these cells decreases after a gluten free diet. These observations suggest that COX-2 mediated prostanoid synthesis contributes to healing of the coeliac mucosa and may be involved in maintenance of intestinal integrity.

Adolescent↗

PubMed2001

Differentially expressed CC3/TIP30 and rab11 along in vivo and in vitro intestinal epithelial cell crypt-villus axis.

We have previously shown that transforming growth factor-beta1 (TGF-beta1) is involved in the fibroblast-induced organization and differentiation of transformed phenotypically crypt-like T84 intestinal epithelial cells into absorptive enterocyte-like cells, when cultured within a three-dimensional collagen gel. We have used differential display polymerase chain reaction to find genes that are either up- or downregulated by TGF-beta in the T84 cells cultured in three-dimensional collagen gel and then studied how these in vitro differentially expressed genes are expressed in vivo in the small intestinal crypt-villus axis. We found that the TGF-beta1-treated T84 cells, like the villus tip enterocytes, expressed increased levels of CC3/TIP30 when compared to the undifferentiated cells. Furthermore, the expression of rab11 showed the opposite pattern, being higher in the undifferentiated cells both in vivo and in vitro. We conclude that the three-dimensional cell culture model where TGF-beta induces organization and differentiation of secretory T84 epithelial cells makes it possible to find up- and downregulated transcripts that also play a role in the human small intestinal crypt-villus axis.

Acetyltransferases↗

PubMed2000

Identification of novel transcription factor-like gene from human intestinal cells.

Intestinal crypt epithelial T84 cells form luminal structures and differentiate to intestinal enterocyte-like cells in response to IMR-90 fibroblast-secreted transforming growth factor-beta when grown within three-dimensional collagen gel. In search of TGF-beta regulated genes involved in this differentiation process, we isolated a TGF-beta downregulated cDNA, human homologue of rat apoptosis antagonising transcription factor that codes for a 560-amino-acid protein. Human AATF-mRNA was expressed at high levels in human brain, heart, thymus, kidney, and placenta while in skeletal muscle and colon the expression was lower. The gene was mapped to chromosome 17q11.2-q12.

Amino Acid Sequence↗

PubMed1987

Results of treatment of stage IA and IIA Hodgkin's disease.

This study analyzed the 5 year actuarial survival and disease-free survival of 122 patients with Stage IA and IIA Hodgkin's disease, (108 patients laparotomy staged) treated with mantle and paraaortic irradiation from 1975 to 1981. Prognostic subgroups and patterns of treatment failure were investigated. The 5 year actuarial survival and disease-free survival was 91% and 75% respectively for the entire group. For Stage IA patients, the 5 year survival and disease-free survival was 92% and 86% respectively, whereas for those in Stage IIA the respective figures were 86% and 65%. Individuals with greater than four sites of involvement at initial presentation; extensive mediastinal adenopathy; hilar or extramediastinal extension to lung, pleura or pericardium, had a poorer 5 year actuarial disease-free survival (43%-60%) than those without these factors (70%-85%). Of the 122 patients, there were 26 relapses: nine infield failures; two concurrent infield and systemic failures; nine marginal recurrences, and three relapses occurring systemically and three in nodal groups not irradiated. Following relapse, 17 patients were salvaged with chemotherapy. Two patients are alive with disease and seven patients died of Hodgkin's disease. Patients with less extensive mediastinal adenopathy and supradiaphragmatic nonmediastinal presentations can be satisfactorily treated with mantle and paraaortic irradiation, whereas patients with extensive mediastinal adenopathy receive six cycles of multiagent chemotherapy before irradiation.

Adolescent↗

PubMed1987

Results of treatment of stage 3A Hodgkin's disease.

From 1975 to 1981, 38 patients with Stage 3A Hodgkin's disease (35 patients pathologically staged) underwent mantle and para-aortic irradiation, and in 36 patients this was preceded or followed by at least six cycles of multiagent chemotherapy. Both the 5-year actuarial survival and disease-free survival for all 38 patients were 83%. There have been six treatment failures: two patients have relapsed within irradiated nodal groups, one patient in apical pericardial lymph nodes as a marginal recurrence, one patient concurrently infield and in unirradiated nodal groups, and two patients systemically (concurrently in unirradiated nodal groups). Of these six relapses, three patients have died of Hodgkin's disease, one patient has been salvaged, and two patients currently are under treatment for salvage. One patient has developed acute nonlymphocytic leukemia and died of this disease. Extensive disease, as estimated by the number of sites of involvement at presentation, degree of splenic involvement, extent of intra-abdominal disease or mediastinal involvement, did not reveal statistically significant prognostic subgroups for relapse. It is currently recommended that patients with Stage 3A Hodgkin's disease receive six cycles of multiagent chemotherapy and mantle and para-aortic irradiation.

Actuarial Analysis↗

PubMed1985

Spring hookwire breast lesion localizer: use with rigid-compression mammographic systems.

Modifications have been made in the spring hookwire system to facilitate accurate three-dimensional placement and to aid surgeons in gauging the location of the hook with respect to a breast lesion. Difficulties in placement of the needle created by rigid compression systems can be overcome by using a combination of a fenestrated compression plate and a spot-compression device.

Biopsy, Needle↗