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Biomedical subjects

O Jensson

Publications and source records attributed to O Jensson.

At least 55 records · Page 3Linked to original sources
PubMed1986

Amyloid fibrils in hereditary cerebral hemorrhage with amyloidosis of Icelandic type is a variant of gamma-trace basic protein (cystatin C).

A gamma-trace variant protein is the major constituent of the amyloid fibrils in patients from Iceland with hereditary cerebral hemorrhage with amyloidosis. The protein consists of 110 residues and is similar to human urinary gamma-trace basic protein (or cystatin C) beginning at its 11th amino-terminal residue. It has an amino acid substitution (glutamine for leucine) at position 58 (position 68 in gamma-trace numbering), which is near the proposed active site of related proteins--namely, cysteine protease inhibitors and kininogens. It is postulated that a point mutation has occurred, leading to the production of an unusual protein that is abnormally degraded, bound, and/or precipitated. Alternatively, gamma-trace basic protein may be genetically polymorphic, and the variant described here may represent an as-yet-undiscovered isotype or an allelic form that is linked to, but not responsible for, the deposition disease. Our data on the structure of a gamma-trace variant protein suggests that its gene expresses a polyprotein precursor in which active peptides are flanked by basic amino acid residues that permit cleavage to liberate small internal peptides. It is likely that the nucleotide sequence coding for Arg-Xaa and Lys-Xaa repeated several times in the molecule may function as alternative splicing sites for mRNA processing.

Amino Acid Sequence↗
PubMed1983

Amyloid fibril in hereditary cerebral hemorrhage with amyloidosis (HCHWA) is related to the gastroentero-pancreatic neuroendocrine protein, gamma trace.

Amyloid fibrils were isolated from the leptomeningeal blood vessels obtained at autopsy from three Icelandic patients dying of Hereditary Cerebral Hemorrhage with Amyloidosis (HCHWA) and verified by Congo red staining and electron microscopy. Gel filtration on Sephadex and Ultrogel columns yielded predominantly one component (molecular weight 11,500 daltons) and also another minor component (molecular weight 15,800 daltons). Automated amino terminal sequencing showed these proteins to be similar (36 residues) to a recently described human protein, gamma trace, beginning at its eleventh amino terminal residue. The amyloid deposits in all three patients stained with rabbit anti-gamma trace antiserum. Although the function of gamma trace is not known, it appears to have structural homology with several hormones and has been localized to the brain, pancreas and pituitary. The amyloid fibril subunits seem to have polymerized after cleavage of the amino terminal decapeptide from gamma trace-related proteins. Therefore, HCHWA appears to be the first genetically determined disease related to the gastroenteropancreatic neuroendocrine system.

Adult↗
PubMed1983

Gc subtypes in Icelanders.

Isoelectric focusing was used to determine the frequencies of Gc subtypes in Icelanders. The gene frequencies observed were Gc1F = 0.107, Gc1S = 0.631 and Gc2 = 0.262. An Icelandic Gc variant allele (Gc Iceland) is shown to have a different isoelectric point from the variant allele Gc-Norway. Gc-Iceland has been detected in 3 unrelated individuals giving the allelic frequency of 0.004 in the Icelandic population. Studies of 65 mother-child pairs confirm the assumed three-allelic mode of inheritance.

Adult↗
PubMed1983

Gc subtypes in Northern Indians.

Isoelectric focusing was used to determine the frequencies of the Gc subtypes in a population sample from The North Indian subcontinent (now living in Birmingham, UK). The gene frequencies observed were as follows: Gc1F = 0.191, Gc1S = 0.519 and Gc2 = 0.290.243 individuals were typed and no variant alleles were detected.

Carrier Proteins↗
PubMed1982

Serum amyloid P-component and C-reactive protein in serum of healthy Icelanders and members of an Icelandic family with macroglobulinaemia.

Serum levels of amyloid P-component (SAP) and C-reactive protein (CRP) were determined in 260 asymptomatic Icelanders of both sexes and various age groups and in 60 members of a family with macroglobulinaemia. In the normal group the SAP levels were normally distributed but slightly higher than in a comparable British group. Elevated levels of SAP and CRP were found in four elderly sibs of the macroglobulinaemia family. Two of them had benign monoclonal macroglobulinaemia (BMM), one had Waldenström's macroglobulinaemia and one increased polyclonal IgA. In addition, a notable small increase (2-20 micrograms/ml) in the levels of CRP was found in 6 children and 3 grandchildren of two elderly sibs with BMM. This increase in serum CRP levels was also found in five of six family members when investigated four years later. The HLA haplotypes present in the family members, including B7, are not closely associated with the various abnormal protein changes detected in the elderly sibs of the second generation or their descendents. Likewise, the increased levels of SAP, CRP or IgM are not associated with any particularly type of the genetic protein markers of blood group systems tested.

Adolescent↗
PubMed1982

Selective serum IgA deficiency in Icelanders. Frequency, family studies and Ig levels.

More than 15,000 Icelanders (6.1% of the population), mostly healthy male blood donors, were screened in 1974-79 for selective IgA deficiency (SIgAD) by immunodiffusion (Ouchterlony). The frequency of SIgAD among blood donors was 1/633 (0.158%). Population and family screening yielded 35 individuals classified as IgA-deficient. Immunoglobulins A, G, M and E were measured in 119 family members of 18 propositi found by screening. Pedigree studies suggested both autosomal dominant and recessive modes of inheritance of SIgAD. A trend toward clustering of similar IgG and IgE levels (within the normal ranges) was apparent in several families. An increased IgG level in family members with SIgAD was significantly more frequent (p less than 0.001) than in members with normal levels of IgA. IgG levels were high in 12 (44%) and normal in 15 of 27 subjects with low or deficient IgA levels who were all healthy when examined, and only 5 gave a history of allergy or recurrent respiratory infections. It is suggested that immune response genes may cause the difference in Ig levels among the SIgAD family members.

Adult↗
PubMed1980

GLO polymorphism in Iceland.

The phenotypes of red cell glyoxalase I (GLO) were determined in two Icelandic population samples using starch-gel electrophoresis and high-voltage agarose-gel electrophoresis. The gene frequencies of 178 individuals were 0.46 for GLO1 and 0.54 for GLO2. In a group of Icelandic insulin-dependent diabetics the gene frequencies were found to be very similar. The evaluation of 30 mother-child pairs is also shown.

Diabetes Mellitus↗
PubMed1979

Anti-tissue antibodies and immunoglobulin levels in relation to HLA and other markers in Icelandic families.

Studies of 521 sera from the Icelandic cousin marriage project were made to assess the incidence of various anti-tissue antibodies and the levels of immunoglobulins, as these were considered to be useful markers of the humoral immune response. Comparisons were made between these parameters and the HLA-A and B antigens, the blood groups, the immunoglobulin allotypes (Gm, Km and Am), the properdin factor (Bf), and other markers. These investigations offered another approach to the study of the sites of action of immune response genes in man. Because the immune response may be expected to differ for each individual and depend at least in part, on the degree of exposure to different antigens, no absolute correlation was expected. There was, however, a marked association between certain IgG anti-tissue antibodies and HLA antigens. This was most marked for HLA-A10, B18 and b27, but not for HLA-A1 or B8. The comparison of immunoglobulin levels with HLA antigens, was less striking, although HLA-A2 appeared to be associated with low levels of IgE. There were also some associations between immunoglobulin levels and ABO blood groups.

Aged↗
PubMed1978

Macroglobulinaemia in an Icelandic family.

Macroglobulinaemia in an Icelandic family is presented. A woman had Waldenström's macroglobulinaemia, and two of her brothers had monoclonal macroglobulinaemia of the benign form. One was asymptomatic, but the other had polyneuropathy and IgM deposits in peripheral nerves. A third brother of these siblings died of a lymphoreticular disease, which presented with a widespread neuropathy. A second sister had polyclonal increase in serum IgA and two other brothers of this sibship had IgM slightly elevated. A study of all descendants (45 in all and 19 spouses) revealed seven individuals with elevated IgM levels. No other immunoglobulin abnormalities were detected.

Aged↗
PubMed1978

On the mapping of PGM3, GLO and HLA.

In a combined Danish, American and Icelandic study, the odds for the orientation PGM3 :GLO:HLA-B:HLA-A versus GLO:HLA-B:HLA-A:PGM3 are estimated to be 75:1. The GLO:HLA recombination frequency is estimated at 5% for males and 12% for females. The recombination fraction for PGM3:GLO is 12--13% in males and is significantly higher in females (approximately free recombination). The findings are consistent with the large sex differences in recombination frequency between HLA and PGM3.

Epitopes↗
PubMed1977

Studies on the Pelger anomaly in Iceland.

An Icelandic family, containing 15 members with Pelger anomally, is reported. Affected individuals in two branches of the family, living in the south-east and east of Iceland, have been traced to common ancestors born 200 years age. The results of scanning of blood films from approximately 20% of the population of Iceland suggest that the Pelger family described contains the only mutation of this kind in Icelanders.

Female↗
PubMed1977

Studies on herediatary spherocytosis in Iceland.

Thirty members with typical hereditary spherocytosis (HS) and over 90 apparently unaffected members belonging to 12 families have been studied. Splenectomy has been performed on 22 HS patients. Of nine HS individuals, who had not undergone surgical treatment in 1957, four suffered from temporary severe anaemia, presumably due to aplastic crisis associated with influenza. One of them died, a male 18 years of age. Pedigree studies on one of the families indicate that the HS gene or genes have been transmitted through six generations over the past 200 years. Marked deficiency in the number of affected compared with the apparently unaffected members in the HS families is present. The most striking example of uneven genetic ratio is a sibship of 15 members investigated haematologically, with one suffering from typical HS. Much reduced penetration of the HS gene or the presence of the socalled "mild form" is upheld as the main explanation for the unevenness in the genetic ratio. However, families are also present in which abortions and death at an early age indicated that selection against the affected could also disturb the genetic ratio in HS families.

Adolescent↗
PubMed1977

Frequency of IgA deficiency in blood donors and Rh negative women in Iceland.

Sera from 6,842 individuals were tested for IgA deficiency, using double and radial immunodiffusion. Sera containing less than 1 mg/100 ml of IgA were classified as deficient. The frequency of selective IgA deficiency among 4,799 blood donors investigated was 1:533, but 1:340 among 1,017 Rh negative women screened and 1:485 for both groups combined. One of the nine IgA deficient blood donors detected belonged to a 1st cousin marriage family previously investigated, in which the mother also was deficient in IgA. One IgA deficient recipient was found among 704 hospital patients screened for this abnormality.

Adolescent↗
PubMed1972

Familial acute myeloid leukaemia with acquired Pelger-Huet anomaly and aneuploidy of C group.

All five members of one generation in an Icelandic family were affected by acute myeloid leukaemia or preleukaemia. Two sibs died of acute myeloid leukaemia and another of myelofibrosis associated with leukaemic changes. The other two sibs are alive; one of them (the propositus) has haematological features consistent with preleukaemia; both of them have evidence of an abnormal cytogenetic clone in the bone marrow with 47 chromosomes, an extra chromosome in the C group. The finding of the acquired Pelger-Huët anomaly in the neutrophils of the five affected sibs suggests that a specific genetic cell defect has been transmitted with autosomal dominant characteristics. The presence of immunological deficiencies and an undue susceptibility to oncogenic viruses, as suggested by warts affecting three family members, may have played a part in the pathogenesis of the leukaemic process.

Adolescent↗