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K Malm

Publications and source records attributed to K Malm.

7 recordsLinked to original sources
PubMed1989

The use of aqueous two-phase systems to concentrate and purify bovine leukemia virus outer envelope protein gp51.

Enzootic bovine leucosis is a chronic lymphoproliferative disease of cattle. The causative agent, bovine leukemia virus (BLV), is related to the human retroviruses HTLV-I and -II. The external env-protein of BLV, a glycoprotein of 51 kDa, carries neutralizing epitopes and should be an essential component in a vaccine against the virus. Problems have been encountered with the concentration and purification of intact virions of BLV and other retroviruses. During centrifugation procedures the external env-proteins are to a great extent detached and consequently poorly recovered with the virion particles. Therefore, other methods are sought to obtain a high yield of the external glycoproteins. The use of two-phase systems based on water soluble polymers is described for the extraction of BLV-gp51 from culture medium. Several polymer systems were tested and the results showed that some were attractive for large scale application. The classical combination dextran-polyethylene glycol gave promising results; a partition coefficient of about 0.02 was obtained for the distribution of the gp51 between the top and combined inter- and bottom phases. In a single extraction step it was possible to obtain 45% of the glycoprotein in a small volume bottom phase and at the same time about 15-fold purified. That should be compared with a recovery of less than 20% with the conventional centrifugation procedures. It is concluded that extraction in phase systems based on water soluble polymers is a methodology well suited for the concentration and purification of BLV-gp51.

Animals↗
PubMedDate not supplied

Concentration and purification of feline leukaemia virus (FeLV) and its outer envelope protein gp70 by aqueous two-phase systems.

The major protective antigens of retroviruses are considered to be their glycosylated envelope proteins. However, the methods commonly employed to enrich and purify virus from culture media such as pelleting and density-gradient centrifugation result in a low recovery of the viral external glycoproteins. This is an obvious drawback when the virus is intended for use in a vaccine. In search for alternative methods to concentrate and purify FeLV, we have attempted extraction in two-phase systems based on water-soluble polymers (Albertsson PA., Biochem Biophys Acta 1958; 27: 378-395). A variety of polymer systems was tested. Some of them seem attractive for a large-scale concentration of the virus and/or its glycoprotein. The distribution between the phases of two FeLV proteins, the outer envelope protein, gp70, and the gag protein, p27, was determined. With a system composed of dextran sulfate and polyvinyl alcohol both the glycoprotein and the gag protein were almost completely recovered in the lower phase which constitutes about 3% of the total system in weight. The two proteins were more than 40-fold purified as calculated on protein basis. The proteins can be extracted readily.

Animals↗
PubMedDate not supplied

Disclosing the diagnosis of pediatric HIV infection: mothers' views.

ISSUES AND PURPOSE: The stigma of HIV infection creates barriers to disclosure. The purpose of this study was to identify to whom biological and foster mothers disclose the diagnosis of HIV infection, discuss their rationale, and describe the recipient's reactions. DESIGN AND METHODS: A descriptive, qualitative study included biological (n = 9) and foster (n = 11) mothers of children with HIV infection. RESULTS: Three themes emerged from the data: Telling for support, determining who should know, and telling children. These themes were present for both biological and foster mothers. PRACTICE IMPLICATIONS: It is important for nurses to realize that parental disclosure of the diagnosis of HIV infection is a long-term, age-appropriate process that will take place over many discussions and time, and should have the support of the interdisciplinary team. Additional psychological support also should be available.

Adult↗