Biomedical subjects

K A Brokstad

Publications and source records attributed to K A Brokstad.

24 records · Page 2Linked to original sources

PubMed1994

Autoantibodies to myelin basic protein are not present in the serum and CSF of MS patients.

Myelin basic protein (MBP) is one of the main constituents of the CNS myelin sheaths, and an autoimmune response directed against MBP may be crucial in the demyelination process in patients with multiple sclerosis (MS). In this study sera and cerebrospinal fluid (CSF) from 25 MS patients, 25 patients with other neurological diseases and 16 healthy controls were examined for antibodies against MBP by using radio immunoblot, western blot, radio immunoassay and enzyme-linked immunosorbent assay. No evidence for the presence of antibodies to MBP was found in sera or CSFs in either the MS patients, or in the control groups tested.

Adult↗

PubMed1994

Serum antibodies from MS patients do not recognize HTLV-I, HIV-1, HIV-2 and SIV.

A retroviral aetiology has been proposed for multiple sclerosis (MS). Although there is as yet no definitive evidence of viral involvement, there have been preliminary reports of antiretroviral antibody detection in sera from MS patients. Such sera have, for example, been found to react with HTLV-I. We here describe investigations involving various immunological techniques which attempt to confirm the virus-specific nature of these antibodies against a range of human and macaque retroviruses. Sera from 25 MS patients, 25 patients with non-associated neurological diseases and 16 patients with non-neurological conditions were tested by immunoblotting methods using lysates of HIV-1-, HIV-2-, HTLV-I- and SIV-infected cells as antigens. None of the sera reacted against any of these retroviral antigens but each serum demonstrated a distinctive and reproducible reaction pattern against cellular components of the cells in which the viruses were propagated. Further examination of the sera was carried out by ELISA using synthetic oligopeptides covering the HIV-1 Gag p24 protein as antigens. None of the sera reacted with the peptides. Our results suggest that in some MS patients the repeated seropositivity to HTLV-I may be due to the reaction with host cell proteins.

Adult↗

PubMed1994

The human immunodeficiency virus type 1 Rev protein shuttles between the cytoplasm and nuclear compartments.

A retroviral regulatory protein, Rev (regulator of virion protein expression), is made in cells infected by human immunodeficiency virus (HIV). Rev is essential for the completion of the retroviral life cycle and interacts with the host cell at some posttranscriptional step in order to express the incompletely spliced HIV mRNAs from which HIV structural proteins are translated. Neither the host cell components nor the mechanisms responsible for this important regulation have been defined. We now report that Rev is a nucleocytoplasmic shuttle protein which is continuously transported between the cytoplasm, the nucleoli, and nucleoplasmic speckles enriched in RNA splicing and processing factors. The results show that Rev has the potential to interfere specifically with the splicing of the HIV pre-mRNA in the nucleoplasm and, next, guide such mRNAs to the cytoplasm for translation.

Amino Acid Sequence↗

PubMed1991

Purification and characterization of a 65-kilodalton diisopropylfluorophosphate-binding protein in the outer membrane of Fusobacterium nucleatum Fev1.

A 65-kilodalton protein was identified in the outer membrane of Fusobacterium nucleatum Fev1 by SDS-PAGE. The relative amount of the protein varied during growth, being greatest in stationary phase. The protein was radio-labeled by [125I]-lactoperoxidase treatment of live cells and was only partially extractable with 2% sodium dodecylsulfate (SDS) at room temperature, and therefore assumed to be both exposed to the cell surface and peptidoglycan associated. In intact cells the protein bound diisopropylfluorophosphate (DFP), indicating that it may be a serine protease. DFP-binding activity depended apparently on proper localization of the proteins in the membrane. Several methods were tried in attempts to purify the 65-kilodalton protein; the method that gave best results was preparative SDS-polyacrylamide gel electrophoresis. The isoelectric point was determined to about pH 5. Amino acid composition analysis showed that the 65-kilodalton protein possesses an excess of hydrophilic over hydrophobic residues, polarity index 52%. The N-terminal end of the protein was apparently blocked.

Amino Acids↗

PubMed1990

Diisopropylfluorophosphate-binding proteins in the outer membrane of Fusobacterium nucleatum: strain variations.

Six strains of Fusobacterium nucleatum were tested for their ability to react with [3H]diisopropylfluorophosphate (DFP), a serine protease inhibitor. Several cytoplasmic proteins were labelled but the strongest labelling was regularly observed in a few outer membrane proteins. The number and the molecular mass of the proteins detected varied according to the strain tested. A 61 kDa protein was labelled in all strains tested, including the two type strains ATCC 10953 and ATCC 25586. A 65 kDa protein was particularly strongly labelled in strains Fev1 and F6.

Bacterial Outer Membrane Proteins↗

PubMedDate not supplied

High prevalence of influenza specific antibody secreting cells in nasal mucosa.

Secretory immunoglobulin A (SIgA) provides the first line of defence against pathogens initiating infection via the mucosal route, e.g. the influenza virus. The aim of this study was to examine the basal level of influenza-specific antibody-secreting cell (ASC) in the local mucosa of the upper respiratory tract. Nineteen patients scheduled for tonsillectomy were enrolled for the study, and they had not experienced influenza during the previous year. Tonsils, blood, oral fluid and a nasal biopsy were sampled, and the basal levels of ASC and antibodies (Abs) were determined. We found low numbers of influenza-specific ASC in the blood and tonsils, but there were about 10-100 times higher numbers of specific ASC in the nasal mucosa tissue despite no recent influenza exposure. Thus, the basal level of influenza-specific ASC in the mucosa of the respiratory tract may be important in the protection against influenza infection.

Adult↗