| 1. |
- Bruder, CEG, et al.
(författare)
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High resolution deletion analysis of constitutional DNA from neurofibromatosis type 2 (NF2) patients using microarray-CGH
- 2001
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Ingår i: Human Molecular Genetics. - Oxford, United Kingdom : Oxford University Press. - 0964-6906 .- 1460-2083. ; 1, s. 271-
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Tidskriftsartikel (refereegranskat)abstract
- Neurofibromatosis type 2 (NF2) is an autosomal dominant disorder whose hallmark is bilateral vestibular schwannoma. It displays a pronounced clinical heterogeneity with mild to severe forms. The NF2 tumor suppressor (merlin/schwannomin) has been cloned and extensively analyzed for mutations in patients with different clinical variants of the disease. Correlation between the type of the NF2 gene mutation and the patient phenotype has been suggested to exist. However, several independent studies have shown that a fraction of NF2 patients with various phenotypes have constitutional deletions that partly or entirely remove one copy of the NF2 gene. The purpose of this study was to examine a 7 Mb interval in the vicinity of the NF2 gene in a large series of NF2 patients in order to determine the frequency and extent of deletions. A total of 116 NF2 patients were analyzed using high-resolution array-comparative genomic hybridization (CGH) on an array covering at least 90% of this region of 22q around the NF2 locus. Deletions, which remove one copy of the entire gene or are predicted to truncate the schwannomin protein, were detected in 8 severe, 10 moderate and 6 mild patients. This result does not support the correlation between the type of mutation affecting the NF2 gene and the disease phenotype. This work also demonstrates the general usefulness of the array-CON methodology for rapid and comprehensive detection of small (down to 40 kb) heterozygous and/or homozygous deletions occurring in constitutional or tumor-derived DNA.
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| 2. |
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| 3. |
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| 4. |
- Ezcurra, Inés, et al.
(författare)
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Transactivation of the Brassica napus napin promoter by ABI3 requires interaction of the conserved B2 and B3 domains of ABI3 with different cis-elements : B2 mediates activation through an ABRE, whereas B3 interacts with an RY/G-box
- 2000
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Ingår i: The Plant Journal. - : Wiley. - 0960-7412 .- 1365-313X. ; 24:1, s. 57-66
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Tidskriftsartikel (refereegranskat)abstract
- The transcriptional activator ABI3 is a key regulator of gene expression during embryo maturation in crucifers. In monocots, the related VP1 protein regulates the Em promoter synergistically with abscisic acid (ABA). We identified cis-elements in the Brassica napus napin napA promoter mediating regulation by ABI3 and ABA, by analyzing substitution mutation constructs of napA in transgenic tobacco plantlets ectopically expressing ABI3. In transient analysis using particle bombardment of tobacco leaf sections, a tetramer of the distB ABRE (abscisic acid-responsive element) mediated transactivation by ABI3 and ABI3-dependent response to ABA, whereas a tetramer of the composite RY/G complex, containing RY repeats and a G-box, mediated only ABA-independent transactivation by ABI3. Deletion of the conserved B2 and B3 domains of ABI3 abolished transactivation of napA by ABI3. The two domains of ABI3 interact with different cis-elements: B2 is necessary for ABA-independent and ABA-dependent activations through the distB ABRE, whereas B3 interacts with the RY/G complex. Thus B2 mediates the interaction of ABI3 with the protein complex at the ABRE. The regulation of napA by ABI3 differs from Em regulation by VP1, in that the B3 domain of ABI3 is essential for the ABA-dependent regulation of napA.
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| 5. |
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| 6. |
- Geldart, M., et al.
(författare)
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A direct comparison of the machining performance of a variax 5 axis parallel kinetic machining centre with conventional 3 and 5 axis machine tools
- 2003
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Ingår i: International journal of machine tools & manufacture. - 0890-6955 .- 1879-2170. ; 43:11, s. 1107-1116
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Tidskriftsartikel (refereegranskat)abstract
- The current trend within the Tool and Die manufacturing sector is to machine components directly from hardened material using high speed 5-axis machining. This has been driven by the increasing requirements for cost competitiveness and lead-time reduction. Significant research effort has been applied to the optimisation of the process with factors such as tooling and machining strategies being considerably improved. However, the underlying structures of the machine tools used have remained unchanged and still consist of a serial kinematic chain. One of the standard justifications for the development of machines designed around parallel kinematic chains is that they should exhibit inherently greater stiffness, have higher axis accelerations and be capable of generating significantly higher cutting forces than conventional serial machines. This suggests that they should be ideally suited to the direct manufacture of tools and dies from hardened material. The comparison of different machine tool types is a complex and difficult process, particularly when their structures are fundamentally different. This paper describes an approach used to compare the performance of three very different types of machines. The technique uses two parameters; surface finish and geometric accuracy to assess the relative performance of different machine tools when cutting hardened material. The method is used to compare a serial kinematic 5-axis machining centre, a serial kinematic 3-axis machining centre and a parallel kinematic 6-axis machining centre. The results of the comparison are presented in this paper and show that all the machine tools performed to an equal standard for materials with a hardness of 54HRc but for very hard materials, 62HRc, the parallel kinematic machine out performed the serial machine tools.
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| 7. |
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| 8. |
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| 9. |
- Larsson, Mårten, et al.
(författare)
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Selective interaction of megalin with postsynaptic density-95 (PSD-95)-like membrane-associated guanylate kinase (MAGUK) proteins
- 2003
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Ingår i: Biochemical Journal. - 0264-6021 .- 1470-8728. ; 373:2, s. 381-391
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Tidskriftsartikel (refereegranskat)abstract
- Megalin is an integral membrane receptor belonging to the low-density lipoprotein receptor family. In addition to its role as an endocytotic receptor, megalin has also been proposed to have signalling functions. Using interaction cloning in yeast, we identified the membrane-associated guanylate kinase family member postsynaptic density-95 (PSD-95) as an interaction partner for megalin. PSD-95 and a truncated version of megalin were co-immunoprecipitated from HEK-293 cell lysates overexpressing the two proteins, which confirmed the interaction. The two proteins were found to be co-localized in these cells by confocal microscopy. Immunocytochemical studies showed that cells in the parathyroid, proximal tubuli of the kidney and placenta express both megalin and PSD-95. We found that the interaction between the two proteins is mediated by the binding of the C-terminus of megalin, which has a type I PSD-95/ Drosophila discs-large/zona occludens 1 (PDZ)-binding motif, to the PDZ2 domain of PSD-95. The PSD-95-like membrane-associated guanylate kinase ('MAGUK') family contains three additional members: PSD-93, synapse-associated protein 97 (SAP97) and SAP102. We detected these proteins, apart from SAP102, in parathyroid chief cells, a cell type having a marked expression of megalin. The PDZ2 domains of PSD-93 and SAP102 were also shown to interact with megalin, whereas no interaction was detected for SAP97. The SAP97 PDZ2 domain differed at four positions from the other members of the PSD-95 subfamily. One of these residues was Thr(389), located in the alphaB-helix and part of the hydrophobic pocket of the PDZ2 domain. Surface plasmon resonance experiments revealed that mutation of SAP97 Thr(389) to alanine, as with the other PSD-95-like membrane-associated guanylate kinases, induced binding to megalin.
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| 10. |
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| 11. |
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| 12. |
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| 13. |
- Rask, Katarina, 1966, et al.
(författare)
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Increased expression of the transcription factors CCAAT-enhancer binding protein-beta (C/EBBeta) and C/EBzeta (CHOP) correlate with invasiveness of human colorectal cancer.
- 2000
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Ingår i: International journal of cancer. Journal international du cancer. - 0020-7136. ; 86:3, s. 337-43
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Tidskriftsartikel (refereegranskat)abstract
- Regulation of cell differentiation is most often impaired in malignant tumors and may represent a key mechanism for the progression of the disease. CCAAT-enhancer binding protein (C/EBP) is a family of transcription factors involved in the regulation of embryonic gut development in rodents, which has also been detected in various malignancies, e.g., liposarcomas and breast and ovarian epithelial tumors. We studied the relationship between C/EBP and tumor histology (Duke's invasive stage and pathological grade) in colorectal cancer. Immunoblotting techniques were used on microdissected fresh frozen tumor specimens, and expression of C/EBPalpha, C/EBPbeta and C/EBPzeta (CHOP) was analyzed in addition to that of the cell-cycle regulator p53 and the proliferation marker PCNA. Expression of C/EBPbeta (LAP isoforms) was markedly increased in all tumors compared with normal colon mucosa. Although the inter-patient variability was large, we found that LIP, the isoform of C/EBPbeta known to inhibit transcription, was expressed at higher levels in Duke's stage B tumors compared with Duke's stage A, whereas Duke's C tumors had the lowest LIP expression. A similar relationship was seen for CHOP. The cell-cycle regulator gene p53 was the only factor that clearly correlated with pathological grade: a decrease in p53 expression was demonstrated. Our data suggest that genetic and cellular events involving C/EBPbeta and CHOP are important for tumor invasion and that these events do not appear to be related to the pathological grade of the tumor.
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| 14. |
- Rask, M, et al.
(författare)
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Forensic psychiatric nursing care--nurses apprehension of their responsibility and work content: a Swedish survey
- 2000
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Ingår i: Journal of Psychiatric and Mental Health Nursing. - : Wiley. - 1351-0126 .- 1365-2850. ; 7:2, s. 163-177
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Tidskriftsartikel (refereegranskat)abstract
- This questionnaire study aimed to investigate nurses' views regarding the areas of responsibility, work content and the theoretical perspectives found to dominate nursing duties in Swedish forensic care. The sample (n = 350) was chosen randomly from the five forensic units which provide treatment for patients in Sweden and there was a response rate of 70% (n = 246). The role of the nurses consisted mainly of actions related to activities of daily living (ADL)-activities. It is worth noting that, within the area of ADL-activities, practical work on the ward was the nurses' most common responsibility as well as work content. Less dominating aspects, were educating patients' families, leading group discussions with family or patients, co-operating with social authorities as well as activities related to life outside the unit. There were no significant differences with regard to gender but several differences between registered nurses (RNs) and licensed mental nurses (LMNs) were noted. There were mostly weak correlations between areas of responsibility or work content and theoretical perspectives. The results thus suggest that nurses in forensic care view their work to be mainly directed at patients' capacity for ADL-activities, medical psychiatric actions, informing and educating patients and families and assessing patients. An even greater emphasis on these aspects may be warranted because of the patients' serious deficits in social and life skills. It may be useful to consider an increased focus on a psycho-educational approach and to develop and test methods focusing on the development of patients' capacity for activities related to daily living in a broad sense. Further research is needed to investigate whether the aspects that dominate nursing care also coincide with what the patients apprehend as beneficial for their recovery.
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| 15. |
- Reidt, W., et al.
(författare)
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Gene regulation during late embryogenesis : the RY motif of maturation-specific gene promoters is a direct target of the FUS3 gene product
- 2000
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Ingår i: The Plant Journal. - : Wiley. - 0960-7412 .- 1365-313X. ; 21:5, s. 401-408
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Tidskriftsartikel (refereegranskat)abstract
- The Arabidopsis mutants fus3 and abi3 show pleiotropic effects during embryogenesis including reduced levels of transcripts encoding embryo-specific seed proteins. To investigate the interaction between the BO-domain-containing transcription factors FUSS and ABI3 with the RY cis-motif, conserved in many seed-specific promoters, a promoter analysis as well as band-shift experiments were performed. The analysis of promoter mutants revealed the structural requirements for the function of the RY cis-element. It is shown that both the nucleotide sequence and the alternation of purin and pyrimidin nucleotides (RY character) are essential for the activity of the motif. Further, it was shown that FUSS and ABI3 can act independently of each other in controlling promoter activity and that the RY cis-motif is a target for both transcription factors. For FUSS, which is so far the smallest known member of the B3-domain family, a physical interaction with the RY motif was established. The functional and biochemical data demonstrate that the regulators FUSS and ABI3 are essential components of a regulatory network acting in concert through the RY-promoter element to control gene expression during late embryogenesis and seed development.
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| 16. |
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| 17. |
- Sakwe, Amos M., et al.
(författare)
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Biosynthesis and secretion of parathyroid hormone are sensitive to proteasome inhibitors in dispersed bovine parathyroid cells
- 2002
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 277:20, s. 17687-17695
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Tidskriftsartikel (refereegranskat)abstract
- Preproparathyroid hormone (prepro-PTH) is one of the proteins abundantly synthesized by parathyroid chief cells; yet under normal growth conditions, little or no prepro-PTH can be detected in these cells. Although this may be attributed to effective cotranslational translocation and proteolytic processing, proteasome-mediated degradation of PTH precursors may be important in the regulation of the levels of these precursors and hence PTH secretion. The effects of N-acetyl-Leu-Leu-norleucinal, N-acetyl-Leu-Leu-methional, carbobenzoxy-Leu-Leu-leucinal (MG132), benzyloxycarbonyl-Ile-Glu(t-butyl)-Ala-leucinal (proteasome inhibitor I), and lactacystin on the biosynthesis and secretion of PTH were examined in dispersed bovine parathyroid cells. We demonstrate that treatment of these cells with proteasome inhibitors caused the accumulation of prepro-PTH and pro-PTH. Compared with mock-treated cells, the processing of pro-PTH to PTH was delayed, and the secretion of intact PTH decreased in proteasome inhibitor-treated cells. Relieving the inhibition of the proteasome by chasing MG132-treated cells in medium without the inhibitor led to the rapid disappearance of the accumulated prepro-PTH, and the rate of PTH secretion was restored to levels comparable to those in mock-treated cells. Furthermore, overexpression of the Hsp70 family of molecular chaperones was observed in proteasome inhibitor-treated cells, and we show that PTH/PTH precursors interact with these molecular chaperones. These data suggest the involvement of parathyroid cell proteasomes in the quality control of PTH biosynthesis.
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| 18. |
- Sakwe, Amos M., et al.
(författare)
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Involvement of protein kinase C-alpha and -epsilon in extracellular Ca(2+) signalling mediated by the calcium sensing receptor
- 2004
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Ingår i: Experimental Cell Research. - : Elsevier BV. - 0014-4827 .- 1090-2422. ; 297:2, s. 560-573
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Tidskriftsartikel (refereegranskat)abstract
- The sensing of extracellular Ca(2+) concentration ([Ca(2+)](o)) and modulation of cellular processes associated with acute or sustained changes in [Ca(2+)](o) are cell-type specific and mediated by the calcium sensing receptor (CaR). [Ca(2+)](o) signalling requires protein kinase C (PKC), but the identity and role of PKC isoforms in CaR-mediated responses remain unclear. Here we show that high [Ca(2+)](o) activated PKC-alpha and PKC- in parathyroid cells and in human embryonic kidney (HEK293) cells overexpressing the CaR (HEK-CaR) and that this response correlated with the CaR-dependent activation of mitogen-activated protein kinases ERK1/2. Activation of ERK1/2 by acute high [Ca(2+)](o) required influx of Ca(2+)through Ni(2+)-sensitive Ca(2+)channels and phosphatidylinositol-dependent phospholipase C-beta activity. Inhibition of PKC by co-expression of dominant-negative (DN) mutants of PKC-alpha or - with the CaR attenuated sustained ERK1/2 activation. Overexpression of a PKC phosphorylation site (T888A) mutant CaR in HEK293 cells showed that this site was important for ERK1/2 activation at high [Ca(2+)](o). Activation of ERK1/2 by high [Ca(2+)](o) was not necessary for the [Ca(2+)](o)-regulated secretion of parathyroid hormone (PTH) in dispersed bovine parathyroid cells. These data suggest that the CaR-mediated [Ca(2+)](o) signal leading to regulated PTH secretion that requires diacylglycerol-responsive PKC isoforms is not mediated via the ERK pathway.
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| 19. |
- Sakwe, Amos M., 1962-
(författare)
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The Role of Protein Kinase C in the Extracellular Ca2+-regulated Secretion of Parathyroid Hormone
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Parathyroid hormone (PTH) is the major physiological regulator of the extracellular Ca2+ concentration ([Ca2+]o) in the body. The secretion of this hormone is suppressed at high [Ca2+]o. Previously this was thought to occur by intracellular degradation of the hormone in the secretory pathway of parathyroid (PT) cells but is now believed to result from extracellular Ca2+ stimulus-secretion coupling via the calcium sensing receptor (CaR). In contrast to the stimulation of PTH secretion upon inhibition of mature PTH proteolysis, inhibition of PT proteasomes caused the accumulation of PTH precursors and inhibited secretion of PTH. This suggests that PT proteasomes play a quality control function in the maturation of PTH but they do not directly participate in the [Ca2+]o-regulated secretion of the hormone. Treatment of PT cells with 12-O-tetradecanyolphorbol-13-acetate (TPA) blocks the high [Ca2+]o-induced CaR-mediated suppression of PTH secretion. To delineate the role of DAG-responsive protein kinase C (PKC) isoforms in this process, we complemented pharmacological modulation of PKC activity with physiological activation of the enzyme via the CaR. PKC-α was rapidly activated by high [Ca2+]o and was efficiently down-regulated by prolonged TPA treatment. In CaR-transfected HEK293 cells, TPA and high [Ca2+]o induced the activation of ERK1/2 but the TPA effect was CaR- and Ca2+-independent. The magnitude of neomycin-induced release of Ca2+ from intracellular stores following pharmacological modulation of PKC activity was opposite to that resulting from physiological activation/inhibition of the enzyme via the CaR. Influx of Ca2+ following activation of the receptor occurred by store-operated mechanisms. Over-expression of wt or DN PKC-α or-ε in PT cells using the Tet-On adenovirus gene delivery system revealed that the stimulatory effect of TPA on PTH secretion at high [Ca2+]o was enhanced in cells over-expressing wt PKC-α, but the coupling of the extracellular Ca2+ signal to PTH secretion was not dependent on the physiological activation of this PKC isoform via the CaR.
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| 20. |
- Sundfeldt, Karin, 1962, et al.
(författare)
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Higher levels of soluble E-cadherin in cyst fluid from malignant ovarian tumours than in benign cysts.
- 2001
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Ingår i: Anticancer research. - 0250-7005. ; 21:1A, s. 65-70
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Tidskriftsartikel (refereegranskat)abstract
- A major diagnostic dilemma in the clinical gynaecological oncology setting is to preoperatively determine whether a complex ovarian mass is benign or malignant. The cell-cell adhesion molecule E-cadherin has previously been localised in biopsies from both benign and malignant epithelial ovarian tumours. In this study, soluble E-cadherin levels was measured with ELISA-technique in peripheral blood, ascites and cystic fluids from patients (n = 33) undergoing surgery for ovarian cystic masses. The levels of soluble E-cadherin were significantly higher in cystic fluid from cystadenocarcinomas (p < 0.001) and borderline tumours (p < 0.05) as compared to cystic fluid from cystadenomas. In ascites fluid and peripheral blood no significant differences were seen. However, ratios of cystic fluid/peripheral blood levels were significantly higher in cystadenocarcinoma (p < 0.001) and borderline tumours (p < 0.05) as compared to benign tumours. In conclusion, measurements of soluble E-cadherin in cystic fluid from patients presenting with complex ovarian masses may be beneficial in increasing the accuracy of preoperative diagnosis.
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