Biomedical subjects

C Linge

Publications and source records attributed to C Linge.

23 records · Page 2Linked to original sources

PubMed1995

Transcription of interferon-alpha 2 alleles from virus-induced human leucocytes and lymphoblastoid cells of African origin.

It has been previously shown that the genomic DNA of both the lymphoblastoid cell line (Namalwa) and certain human donors (of African origin) contain sequences corresponding to two allelic variants, b and c, of the interferon-alpha 2 gene (IFNA2). Little is known however about the relative expression of these two alleles in heterozygous cells. We have therefore examined the transcription of allelic variants of the human IFNA2 locus by both normal human leucocytes (from a heterozygous donor) and Namalwa cells. Analysis of cDNA clones identified sequences of both allelic variants, IFNA2b and c, indicating active transcription by both cell types. Analysis of tryptic and peptic peptides derived from purified IFN-alpha 2 also demonstrated both IFN-alpha 2b and IFN-alpha 2c proteins. Populations of virus induced heterozygous cells can therefore effectively transcribe and secrete both forms of IFN-alpha 2 simultaneously, with no apparent restrictions on expression of either allele.

Alleles↗

PubMed1995

Interferon system defects in human malignant melanoma.

We have examined the ability of melanoma cell lines and normal human melanocytes, which have demonstrable intact IFN genes, to secrete both IFN-alpha and IFN-beta in response to induction with virus. Normal melanocytes were found to secrete both IFN-alpha and IFN-beta after virus induction. In contrast, although all but one of the melanoma lines tested were capable of secreting IFN-beta, none were capable of IFN-alpha secretion. This phenomenon was not due to defects in either translation of IFN-alpha mRNA or secretion of IFN-alpha proteins, since transfection of melanoma lines with a constitutive IFN-alpha 2b expression vector resulted in the secretion of high levels of IFN. On further examination, this inability to express natural IFN-alpha appeared to be due to a defect in activation of the IFN-alpha promoters, since constructs containing the IFN-alpha promotor were completely unresponsive to viral infection in melanoma cells but inducible in melanocytes. These results show that there is a specific disruption of IFN-alpha gene activation rather than IFN-beta in melanoma lines and suggest that this is due to disruption of a trans-acting IFN-alpha gene transcription factor. Disruption of this factor and its consequences may be important in the development of malignant melanoma.

Base Sequence↗

PubMed1991

Entrapment of a Swan-Ganz-catheter in tricuspidal valve.

Unsuccessful pulmonary artery catheter removal is a rare but potential life-threatening complication. This was observed in a dog during investigations on cerebrovascular reactivity. Postmortem examination showed entrappment of the pulmonary artery catheter in tricuspidal valve. "Clinical" symptoms are described and therapeutic measures in the case of suspected entrappment are discussed.

Animals↗

PubMed1989

A method for removal of fibroblasts from human tissue culture systems.

The phenomenon of fibroblast overgrowth is one of the major problems encountered during long-term culture of more slowly growing specialized cell types. A cell surface glycoprotein, Thy-1, which was originally found to be present on murine T-lymphocytes and brain cells, is also found to be present on only a few human cell types, mainly fibroblasts and neuronal cells. We have taken advantage of this fact, using a solid-phase immunoadsorption technique termed "panning", to rid our culture system (normal human keratinocytes) of contaminating dermal fibroblasts. A mouse monoclonal antibody raised against human brain Thy-1 was used to attach dermal fibroblasts to a goat anti-mouse immunoglobulin-coated plastic surface. By this method we were able to separate a 1:1 mixture of human dermal fibroblasts and keratinocytes with greater than 97.5% efficiency. Furthermore we have successfully removed dermal fibroblasts from naturally arising contaminated keratinocyte cultures, where the proportion of fibroblasts (less than 10%) was considerably less than that of the artificially mixed populations. These results compare favorably with those expected of the fluorescence-activated cell sorter (FACS) method of cell separation. In addition this technique is comparatively simple and inexpensive and is thought to be of use to other primary tissue culture systems (especially human) where contamination and subsequent overgrowth with fibroblasts remains a problem.

Cell Adhesion↗

PubMed1988

[Differential diagnosis of malignant hyperthermia, febrile catatonia and neuroleptic malignant syndrome. A case comparison].

Malignant Hyperthermia (MH), Lethal Catatonia (LC), and Neuroleptic Malignant Syndrome (NMS) are known as rare potential lethal diseases. MH and NMS--both being drug-induced--have in common some main symptoms. LC and NMS, on the other hand, are hardly distinguishable by clinical means. After presentation of the case reports the differential diagnosis of the syndromes is discussed. While there is strong evidence for the MH to be drug-induced, the NMS cannot be explained sufficiently in this way. Clinically both can be differentiated. Lethal catatonia is a syndrome rather than a specific disease. Differential diagnosis for NMS is possible by the neuroleptic withdraw-trial.

Adult↗