| 1. |
- Vujic, Mihailo, 1945, et al.
(författare)
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Localization of a gene for autosomal dominant Larsen syndrome to chromosome region 3p21.1-14.1 in the proximity of, but distinct from, the COL7A1 locus.
- 1995
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Ingår i: American journal of human genetics. - 0002-9297. ; 57:5, s. 1104-13
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Tidskriftsartikel (refereegranskat)abstract
- Larsen syndrome (LS) is a skeletal dysplasia (osteochondrodysplasia) in which multiple dislocations of the large joints are the major feature. Nosology in this group of diseases, which constitutes 8% of Mendelian disorders in man, is primarily based on clinical and radiographic features. Hopes for more accurate classification grounds are currently being met by progress in elucidation of underlying genetic defects. We have performed linkage analysis in a large Swedish kindred with autosomal dominant LS and found the gene (LAR1) to be strongly linked to chromosome 3p markers (Zmax = 13.4 at (theta = .00). Recombination analysis indicates that the LAR1 locus is located in a region defined distally by D3S1581 and proximally by D3S1600, which cytogenetically maps to chromosome region 3p21.1-14.1. Linkage and recombination analysis of a COL7A1 PvuII intragenic polymorphism versus LS and chromosome 3 markers indicate that COL7A1 is located close to, but distinct from, the LAR1 locus.
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| 2. |
- Källberg, Eva, et al.
(författare)
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The effect of carrier and carrier priming on the kinetics and pattern of somatic mutation in the V chi Ox1 gene
- 1995
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Ingår i: European Journal of Immunology. - : Wiley. - 0014-2980 .- 1521-4141. ; 25:8, s. 54-2349
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Tidskriftsartikel (refereegranskat)abstract
- Priming mice with a chicken gamma globulin (CGG) carrier protein significantly accelerated the onset of somatic mutation in the V chi Ox1 gene when the mice were subsequently immunized with 2-phenyl-5-oxazolone (phOx) coupled to CGG. The first mutations were already detected 7 days after immunization, while in the true primary response, they are not apparent until day 10. It was also found that comparing the mutation pattern of V chi Ox1 genes from hybridomas derived after immunization with phOx coupled to different carriers revealed quite distinct patterns of somatic mutation. Analysis of hybridoma sequences from the primary immune response to phOx-ovalbumin showed that the codons for Ser29, Ser31 and Lys45 were hot-spots for somatic mutation. Thus, the frequency and pattern of somatic mutations in the V chi Ox1 gene depends on the available T cell help as well as on the complex structure of the immunizing antigen.
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| 3. |
- van Dijk-Härd, Iris, et al.
(författare)
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Age-related impaired affinity maturation and differential D-JH gene usage in human VH6-expressing B lymphocytes from healthy individuals
- 1997
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Ingår i: European Journal of Immunology. - : Wiley-VCH Verlagsgesellschaft. - 0014-2980 .- 1521-4141. ; 27:6, s. 1381-1386
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Tidskriftsartikel (refereegranskat)abstract
- To elucidate the basic molecular events underlying humoral immunity during ontogeny and senescence, we analyzed a panel of 179 polymerase chain reaction-derived VH6-D-JH rearrangements from cord blood, peripheral blood, and spleen. Nucleotide sequence analysis of the CDR3 region shows that there is a difference in D and JH gene usage in functional rearrangements between lymphocytes from peripheral blood and spleen. Analysis of the VH6 gene shows that the mutational frequencies rise from 0.81% in cord blood to 1.96% in peripheral blood lymphocytes derived from young adults, and decrease to 0.80% in samples from individuals older than 50 years. The number of rearrangements carrying mutations follows a similar pattern: 22% in cord blood, 73% in the age group 20-49 years, and 57% in the age group over 50 years. The mutational frequencies among the mutated genes are, however, similar for cord blood and young adults, 2.76% and 2.51%, respectively, and 1.3% in older adults. These data show an age-related impaired affinity maturation which might relate to the decrease in immunological responsiveness among the elderly.
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| 4. |
- Adeyinka, Adewale
(författare)
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Cytogenetic studies of primary and metastatic breast cancer
- 1999
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A series of primary and metastatic breast carcinomas obtained from female and male patients were cytogenetically analysed. Trisomy 12 was identified as a recurrent and sometimes early event in breast carcinogenesis. Also, multiple polysomies involving chromosomes 1, 5, 6, 7, 12, 16, 18, and 19 were identified as a possible pathway of progression in a subset of carcinomas. Among the male breast carcinomas, +7, del(16)(q13) and +20 were identified as recurrent changes. A study of invasive breast carcinomas of histological types usually considered to be prognostically favourable revealed that medullary carcinomas are cytogenetically more complex than mucinous and tubular carcinomas, with medullary carcinomas often exhibiting karyotypic features that have previously been associated with aggressive breast carcinomas, i.e., highly complex chromosome aberrations with near-triploid chromosome numbers. A cytogenetic comparison of primary breast carcinomas and their lymph node metastases, as well as a comparison of chromosomal imbalances in node-positive and node-negative primary breast carcinomas, showed that monosomy for chromosomes 17, 18, and 22 seem to be important in the metastatic process. On the other hand, loss of material from the proximal part of the long arm of chromosome 6 and loss of the long arm of chromosome 16 were preferentially associated with a node-negative phenotype in primary breast cancer.
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| 5. |
- Afrakhte, Mozhgan
(författare)
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Growth control mechanisms in normal and neoplastic mammalian cells
- 1998
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The main theme of the studies presented in this thesis is, the growth control mechanisms whose loss in normal cells predispose to or cause cancer. The balance between growth inhibitory and stimulatory mechanisms is crucial for the development and maintenance of a normal animal.PDGF, a growth factor for cells of mesenchymal origin, is implicated in normal developmental processes as well as neoplasia. The alternative splicing of exon 6 in PDGF-A gene transcripts gives rise to two different proteins with different compartmentalization properties. The PDGF-A chain homodimers, PDGF-AAL, encoded PDGF A-splice variant remain associated with the cell membrane. Studies of a human fibrosarcoma cell line, U-2197, revealed a high expression level of the cell associated PDGF-AAL which upon release increased autophosphorylation of the endogenous PDGF receptors, suggesting an autocrine loop. PDGF-A gene and PDGFR-α gene found to be co-amplified in the U-2197, indicating an optimised system for growth in these cells, i.e. amplified growth factor receptor as well as a local autocrine supply of the mitogen.Members of TGFβ superfamily are potent regulators of the growth and differentiation of a wide range of cell types. Intracellular mediators of TGF-β signalling, SMADs, transduce signals from serine/threonine kinase receptors to the nucleus where they affect transcription of target genes. A new class of SMAD proteins has been identified whose members, the inhibitory SMADS, antagonise TGF-β signals by interfering with agonistic SMADs activity. Smad6 and Smad7 are two closely related TGF-β antagonists identified in mammalian cells. Overexpression of Smad7 inhibited the cellular response to TGF-β whereas expression of an anti-sense Smad7 construct showed an enhancing effect on this response. The inhibitory SMADs may act in a negative feedback loop, as their expression is induced by the same ligands whose action they antagonise.Density dependent growth inhibition is a growth control mechanism often lost in transformed and malignant cells. Cells in dense culture are refractory to the mitogen stimulation although, the mitogenic signals were shown to be processed to some extent. The expression of immediate-early genes in dense culture stimulated with mitogen was induced. The activity of cyclin dependent kinases (CDKs), the pivotal kinases in G1/S transition, showed to be density dependent and decreased by increasing cell density. pRb, a tumour suppressor and growth regulatory protein, remained unphosphorylated in mitogen treated dense culture. The cessation of CDKs kinase activity in dense cultures was shown to be accompanied with increasing expression of inhibitory proteins of these kinases, CKIs. The impaired expression of a positive regulator of CDKs, Cdc25A phosphatase, was another feature of dense cultures.
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| 6. |
- Ager, S, et al.
(författare)
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Retroviral display of antibody fragments; interdomain spacing strongly influences vector infectivity
- 1996
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Ingår i: Human Gene Therapy. - : Mary Ann Liebert Inc. - 1043-0342 .- 1557-7422. ; 7:17, s. 2157-2164
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Tidskriftsartikel (refereegranskat)abstract
- Five different single-chain antibody fragments (scFv) against human cell-surface antigens were displayed on murine ecotropic retroviral vectors by fusing them to the Moloney SU envelope glycoprotein. The spacing between the scFv and the SU glycoprotein was varied by fusing the scFv to residue +7 or to residue +1 of Moloney SU and by inserting linker sequences of different lengths between the domains. All of the chimeric envelopes were efficiently incorporated into vector particles and could bind to human cells through their displayed antibody fragments, but did not infect them. The spacing between the scFvs and the SU glycoproteins had no significant effect on the efficiency of envelope expression or viral incorporation and did not affect the binding properties of the chimeric envelopes, nor did it influence the efficiency of targeted gene delivery to human cells by scFv-displaying vectors. However, on murine fibroblasts the infectivity of vectors incorporating the chimeric envelopes was strongly influenced by the length of the interdomain spacer. The titers were very low when the single-chain antibodies were fused through a tripeptide linker to SU residue +7 and were greatly enhanced (up to 10(5)-fold) when they were fused to SU residue +1 through a heptapeptide linker. These results point to the importance of steric interactions between the domains of chimeric envelope glycoproteins and may have implications for retroviral vector design for human gene therapy.
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| 7. |
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| 8. |
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| 9. |
- Andreasson, Patrik, et al.
(författare)
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BCR/ABL-negative chronic myeloid leukemia with ETV6/ABL fusion
- 1997
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Ingår i: Genes, Chromosomes and Cancer. - 1045-2257. ; 20:3, s. 299-304
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Tidskriftsartikel (refereegranskat)abstract
- A BCR/ABL-negative chronic myeloid leukemia (CML) with t(12;14) (p12;q11-13) as the sole chromosomal abnormality was investigated by fluorescence in situ hybridization (FISH), which disclosed a cryptic insertion of ETV6 (previously called TEL), located at 12p12, into ABL at chromosome band 9q34. ETV6/ABL fusion was confirmed by RT-PCR, revealing that the first five exons of ETV6 were fused in frame with ABL at exon 2. Wild-type ETV6 was expressed, in accordance with the FISH results showing no deletion of the second ETV6 allele. ETV6/ABL chimeric transcripts have previously been reported in acute leukemias, but never before in CML. The present case suggests that ETV6/ABL positivity may constitute a new genetic subgroup of BCR-negative CML.
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| 10. |
- Ata, Ahmad Khaled
(författare)
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Expression of TGF- isoforms, their receptors and related SMAD proteins in brain pathology : Immunohistochemical studies focusing on infarcts, abscesses and malignant gliomas
- 1999
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis focuses on the immunohistochemical expression of transforming growth factor beta(TGFβ) isoforms, their receptors and TGF-β-related SMAD proteins in brain pathology, chiefly in-farcts. One key question was whether the expressions of these compounds are altered within glial cells, endothelial cells of microvessels and other cell types in the vicinity of infarcts. Studies on human and animal brain infarcts were made. Immunoreactivities to TGF-β isoforms -β1, -β2 and -β3, and TGF-βreceptor (TβR) type I were seen in astrocytes, macrophages, neurons, endothelial and vascular smooth muscle cells of human brain infarcts. Similar observations were made in an experimental model of rat brain infarct at day 1 and 3 following occlusion of the middle cerebral artery (MCA). Increased expression of Smad2, -3, -4, -6 and -7 was seen already at 6 h after MCA occlusion in neurons, microvascular endothelial cells, astroglial cells and inflammatory cells. Later on, immunopositive macrophages were present in the infarcts. The changes persisted even at day 7 after MCA occlusion.Several alterations thus occur during the evolution of brain infarcts with regard to the immunohistochemical expression of TGF-β, its receptors and related SMAD proteins. Such changes are, however, not unique to brain infarcts. Thus, patterns of high expression for TGF-β- isoforms -β1, -β2 -β3, and TβR-I in cases of brain abscess (human), and of Smad2, -3, -4, -6 and -7 in tumor cells and neoplastic blood vessels of malignant gliomas (human) were also observed.In addition, immunohistochemical expression of vascular endothelial growth factor (VEGF) andits receptors was investigated since this growth factor is involved in angiogenesis and edemaformation, two cardinal features of brain infarcts. Increased immunoreactivities, seen particularly in the edges of infarcts, were observed already at day 1 after MCA occlusion.In conclusion, the various TGF-β isoforms, receptors and related SMAD proteins, together with other factors, seem to be involved in the very complicated and important changes taking place in the vicinity of brain infarcts.
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