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G Marhaug

Publications and source records attributed to G Marhaug.

At least 37 records · Page 2Linked to original sources
PubMed1994

Serum amyloid A protein in mink during endotoxin induced inflammation and amyloidogenesis.

Two-dimensional electrophoresis was used to study SAA and AA proteins in mink during lipopolysaccharide-induced inflammation and amyloidogenesis. Three isotypes, SAA pI 6.8 and SAA pI 6.5 (both SAA1-like), and SAA pI 6.0 (SAA1- and SAA2-like), were identified in serum after both single and multiple LPS injections. Total SAA serum levels were highest in the early phase of induction, followed by a decrease ranging from 1 to 50% of the peak value during the rest of the experiment. The variation in the total SAA levels correlated with the total SAA mRNA levels. Low total SAA levels were seen both in non-amyloidotic and amyloidotic animals, and a general decrease of all isotypes was demonstrated. In hepatic amyloid fibrils, several AA isotypes, with amino acid sequence homologous exclusively to that of SAA2, were found. In the corresponding splenic material, fragments of histones H2A and H2B constituted most of the low molecular mass proteins, and no protein AA was detected. In spite of low serum levels and a non-specific isotype removal, the results confirm that SAA2 is amyloidogenic in mink.

Amino Acid Sequence↗
PubMed1993

Expression of serum amyloid A genes in mink during induction of inflammation and amyloidosis.

Serum amyloid A (SAA) is an acute phase protein and the precursor of amyloid protein A (AA) in deposits of secondary amyloidosis. Several isotypes exist in mink, but previous studies suggest that mink AA is derived from only one. To assess the effect of repeated episodes of inflammation and induction of amyloidosis, qualitative and quantitative changes in hepatic and extrahepatic SAA mRNA were studied. Young female mink received subcutaneous lipopolysaccharide injections for amyloid induction. Studies were performed using RNA probes and oligonucleotide probes specific for each of two SAA mRNA species. Northern blot hybridization showed that hepatic SAA1 and SAA2 mRNA levels increased dramatically after inflammatory stimulation, and were subsequently maintained at elevated levels, showing considerable interindividual variation, but only a slight decrease during repeated inflammatory stimuli and the early stages of amyloid deposition. No preferential accumulation of mRNA specifying a particular isotype was found during the experiment. Differential expression of mink SAA mRNA during repeated inflammatory stimulation does not seem to explain why only SAA2-derived AA is found in amyloid deposits. Extrahepatic SAA mRNA seemed to be independently regulated and may thus represent another, yet not characterized, SAA isotype.

Amyloidosis↗
PubMed1993

Characterization and quantification of mink serum amyloid A protein using two-dimensional electrophoresis with immobilized pH gradients.

Using hydrophobic interaction chromatography, two-dimensional electrophoresis with an immobilized pH gradient in the first dimension and semidry blotting, three isoforms of mink serum amyloid A protein (SAA) were characterized and studied during chronic inflammation. Compared to conventional methods that have been applied to SAA, the major advantages of the present combination of methods are: (i) use of small serum volumes, (ii) rapid extraction, (iii) high resolution, and (iv) high yield of proteins.

Acute-Phase Reaction↗
PubMed1993

The revised amino acid sequence of serum amyloid A (SAA) protein in mink.

The revised amino acid sequence of mink protein SAA was shown to be composed of 111 amino acid residues. The protein has an insertion of eight amino acid residues compared with that reported earlier. Microheterogeneities were observed in positions 6, 10, 24, 27, 67 and 71. The amino acid sequence is in accordance with the SAA mink cDNA sequences, except for the phenylalanine in position 6. The data indicate a third SAA gene in mink.

Amino Acid Sequence↗
PubMed1993

Differential expression of rabbit serum amyloid A genes in response to various inflammatory agents.

Serum amyloid A (SAA) is an acute-phase plasma protein which increases up to 1000-fold after an acute-phase stimulus. Several SAA genes and corresponding protein isotypes exist in individual species. Liver is the main source of production, but extra-hepatic SAA expression has been described. In this study inflammation was induced in rabbits with lipopolysaccharide, turpentine, or casein. Transcription of SAA mRNA was studied using Northern blot analysis with probes specific for three different rabbit SAA isotypes and analysed by scanning densitometry. In the stimulated liver slight variation in SAA mRNA transcription level was seen after stimulation with different inflammatory agents. After lipopolysaccharide-stimulation SAA gene expression was also seen in most of the extra-hepatic organs. After turpentine stimulation SAA mRNA was seen in the liver, the ovary, and the small intestines, and after casein stimulation only in the liver and the ovary. SAA1 and SAA2 were induced exclusively in the liver, while SAA3 was induced mainly in the extra-hepatic organs. This indicates that the SAA genes probably are independently regulated both in relation to stimulus, gene- and tissue-specificity.

Acute-Phase Reaction↗
PubMed1993

The primary structure of rabbit serum amyloid A protein isolated from acute phase serum.

Serum amyloid A (SAA) protein, a sensitive acute phase protein and the precursor of protein AA in secondary amyloid, was purified from pooled acute phase rabbit serum using two different methods: isolation of protein SAA directly by octyl-Sepharose chromatography of total serum, and dissociation and isolation of apoSAA from acute phase high density lipoprotein (HDL). The protein SAA fraction obtained was further purified using gel filtration and ion exchange chromatography. Rabbit protein SAA has 104 amino acid residues, like human SAA, and has a partially blocked N terminus. The highly conserved region from position 33 to position 63 found in SAA from all species studied was confirmed also in rabbit SAA. No microheterogeneities were observed. The amino acid sequence showed extensive N-terminal homology with the rabbit amyloid A protein, except for the microheterogeneity in position 12 in protein AA. It also showed identical amino acid sequence with that deduced from the rabbit cDNA clone pSAA 55. Complete homologies were found with clone SAA 2, except for positions 22 and 78, clone SA8-1, except for positions 22 and 79 and clone SA7-3, except for position 22. This pSAA 55/SA7-3/SA8-1/SAA2-like protein was the only SAA isotype found both in total serum and in the HDL fraction. Isotypes corresponding to other SAA-like genes could not be found in this pool of acute phase rabbit sera.

Acute-Phase Reaction↗
PubMed1993

Coeliac disease and gluten-free diet: a following-up study of fifteen young adults.

Fifteen patients with coeliac disease diagnosed in infancy and early childhood between 1959 and 1971 were included in the study. The primary diagnosis was made on the basis of typical symptoms and signs, stool examination for fat, xylose test and clinical and laboratory improvement after introduction of gluten-free diet. All patients were challenged with gluten for a minimum of 4 weeks to 4 years before a peroral proximal jejunal biopsy was performed between 1973 and 1976. The biopsy specimen showed changes consistent with coeliac disease in all patients. Gluten-free diet induced again clinical recovery and was recommended as a life-long diet. The patients were reinvestigated after 15-18 years (mean 17 years) and 13 biopsies were evaluated. Five of these biopsy specimens showed variable histopathological changes. Only 5 patients were still on a strict gluten-free diet. There was no correlation between the presence of gastro-intestinal symptoms and abnormal biopsies. All patients had haematological tests within the normal range. Anti-gliadin IgA levels above the upper normal limit were found in 2 out of 3 patients with grade IV histopathological changes in the mucosa, and in 1 of the patients on a normal diet who refused to have a biopsy performed. The patients' knowledge of their disease was evaluated, and suitable follow-up programs for coeliac patients are discussed.

Biopsy↗
PubMed1993

Idiopathic juvenile osteoporosis.

Osteoporosis is the most common bone disease in adults, but rarely occurs in children. A seven year old boy with idiopathic juvenile osteoporosis is reported. X-ray investigation revealed moderate generalized osteoporosis with compression fractures and wedging of the thoracic and lumbar vertebral bodies. Clinical examination and biochemical investigations ruled out the known causes of osteoporosis in childhood. During the following four years he complained of back pain, but no new fractures appeared. Entering puberty he improved both clinically and radiologically without treatment.

Child↗
PubMed1991

Rabbit serum amyloid protein A: expression and primary structure deduced from cDNA sequences.

Serum amyloid A protein (SAA), the precursor of amyloid protein A (AA) in deposits of secondary amyloidosis, is an acute phase plasma apolipoprotein produced by hepatocytes. The primary structure of SAA demonstrates high interspecies homology. Several isoforms exist in individual species, probably with different amyloidogenic potential. The nucleotide sequences of two different rabbit serum amyloid A cDNA clones have been analysed, one (corresponding to SAA1) 569 base pairs (bp) long and the other (corresponding to SAA2) 513 bp long. Their deduced amino acid sequences differ at five amino acid positions, four of which are located in the NH2-terminal region of the protein. The deduced amino acid sequence of SAA2 corresponds to rabbit protein AA previously described except for one amino acid in position 22. Eighteen hours after turpentine stimulation, rabbit SAA mRNA is abundant in liver, while lower levels are present in spleen. None of the other extrahepatic organs studied showed any SAA mRNA expression. A third mRNA species (1.9 kb) hybridizing with a single-stranded RNA probe transcribed from the rabbit SAA cDNA, was identified. SAA1 and SAA2 mRNA were found in approximately equal amounts in turpentine-stimulated rabbit liver, but seem to be coordinately decreased after repeated inflammatory stimulation.

Amino Acid Sequence↗
PubMed1990

Mink serum amyloid A protein. Expression and primary structure based on cDNA sequences.

The nucleotide sequences of two mink serum amyloid A (SAA) cDNA clones have been analyzed, one (SAA1) 776 base pairs long and the other (SAA2) 552 base pairs long. Significant differences were discovered when derived amino acid sequences were compared with data for apoSAA isolated from high density lipoprotein. Previous studies of mink protein SAA and amyloid protein A (AA) suggest that only one SAA isotype is amyloidogenic. The cDNA clone for SAA2 defines the "amyloid prone" isotype while SAA1 is found only in serum. Mink SAA1 has alanine in position 10, isoleucine in positions 24, 67, and 71, lysine in position 27, and proline in position 105. Residue 10 in mink SAA2 is valine while arginine and asparagine are at positions 24 and 27, respectively, all characteristics of protein AA isolated from mink amyloid fibrils. Mink SAA2 also has valine in position 67, phenylalanine in position 71, and amino acid 105 is serine. It remains unknown why these six amino acid substitutions render SAA2 more amyloidogenic than SAA1. Eighteen hours after lipopolysaccharide stimulation, mink SAA mRNA is abundant in liver with relatively minor accumulations in brain and lung. Genes encoding both SAA isotypes are expressed in all three organs while no SAA mRNA was detectable in amyloid prone organs, including spleen and intestine, indicating that deposition of AA from locally synthesized SAA is unlikely. A third mRNA species (2.2 kilobases) was identified and hybridizes with cDNA probes for mink SAA1 and SAA2. In addition to a major primary translation product (molecular mass 14,400 Da) an additional product with molecular mass 28,000 Da was immunoprecipitable.

Amino Acid Sequence↗
PubMed1987

The amino acid sequence of serum amyloid A (SAA) protein in mink.

The amino acid sequence of serum amyloid A (SAA) protein from mink was established by characterization of peptides derived from digestion of the protein with trypsin and from cleavage with BNPS-skatole. In three positions, two amino acid residues were found, showing that the protein is polymorphic. In position 10 both valine and isoleucine were found, while only valine was observed in protein AA. Prominent sequence homologies with protein SAA and protein AA from other species were seen, particularly corresponding to the segment between positions 31 and 54, but also in the C-terminal part of protein SAA, which is not shared by protein AA.

Amino Acid Sequence↗
PubMed1986

Serum amyloid A protein in acute myocardial infarction.

Tissue injury including myocardial infarction leads to a variety of changes in plasma proteins commonly referred to as "the acute phase response". In this report the concentrations of serum amyloid A protein (SAA) were measured serially in 6 patients with myocardial infarction and 4 with angina. SAA was found to be increased in all patients with infarction, but in no patients with angina. Significantly increased SAA levels were detected 12 hours after the peak level of creatine kinase, and the concentrations of SAA seemed to correlate to the amount of damaged tissue. The SAA-response was both faster and more extensive than the response of C-reactive protein (CRP), but the correlation between SAA and CRP was very good.

Aspartate Aminotransferases↗
PubMed1986

Characterization of amyloid protein AA and its serum precursor SAA in the horse.

Amyloid was extracted from the liver of a horse that had developed amyloidosis after being used for several years for the production of antibodies to bacterial antigens. The amyloid fibrils were shown to be of the AA type. Two AA proteins with molecular weights of 9000 and 11,000 and with identical partial N-terminal amino acid sequences were identified. Marked structural homology with AA from other species including man was seen, although clear species-related antigenic specificity was observed. SAA isolated from an acute phase (septic abortion) horse serum was identical to AA with respect to antigenicity and the 10 first N-terminal amino acid residues that have been studied up to now. The bulk of SAA was present in the high-density lipoprotein complex in serum. Also SAA was heterogeneous with respect to size, most molecules having a molecular weight of 11,000, and a minority 9000.

Amino Acid Sequence↗
PubMed1985

Transformation of amyloid precursor SAA to protein AA and incorporation in amyloid fibrils in vivo.

Experimental amyloidosis was induced in mice by intraperitoneal injections of endotoxin (lipopolysaccharide (LPS)). In addition to LPS, a group of mice received high-density lipoprotein (HDL)-SAA complexes isolated from human acute-phase serum, whereas a group of control mice received saline in addition to LPS. Isolated amyloid fibrils from the mice given HDL-SAA contained human AA protein, as shown by immunodiffusion, immunoblot, and enzyme-linked immunosorbent assay techniques, in addition to mouse AA. In contrast, amyloid from the control mice contained exclusively AA of mouse origin. Thus, the experiments provided solid evidence that SAA is the precursor for amyloid fibril protein AA.

Amyloid↗
PubMed1985

Amyloid-related serum protein (SAA) during and after pregnancy in healthy women and women with rheumatic disease.

The usefulness of amyloid-related serum protein (SAA) as an indicator of disease activity has been evaluated in 11 patients with rheumatoid arthritis (RA), 2 patients with psoriatic arthritis (PA) and 13 patients with ankylosing spondylitis (AS) prospectively studied during and after pregnancy. For comparison, SAA levels were recorded serially during and after pregnancy in 28 healthy pregnant women. SAA levels were unaltered by gestation and thus within the normal range during normal pregnancy, but were raised in healthy pregnant women with episodes of intercurrent infections. In RA and AS patients, SAA concentrations correlated to disease activity during and after pregnancy. Serial levels of SAA and C-reactive protein in healthy women and patients paralleled each other with the most pronounced inflammatory response displayed by SAA. We conclude that SAA is a sensitive and reliable indicator of inflammatory events both in the pregnant and non-pregnant state.

Amyloid↗