| 1. |
- Beckman-Sundh, Ulla, et al.
(författare)
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A screening method for phosphohistidine phosphatase 1 activity
- 2011
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Ingår i: Upsala Journal of Medical Sciences. - : Uppsala Medical Society. - 0300-9734 .- 2000-1967. ; 116:3, s. 161-168
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Tidskriftsartikel (refereegranskat)abstract
- Introduction. Research in the field of protein-bound phosphohistidine phosphorylation has been hampered by the difficulties in analysis and detection of phosphohistidine. Therefore a screening method was developed primarily for the analysis of phosphohistidine phosphatase 1 (PHPT1) activity. Methods. A highly positively charged substrate, Ac-Val-Arg-Leu-Lys-His-Arg-Lys-Leu-Arg-pNA, containing the peptide surrounding the phosphorylated histidine in ion channel KCa3.1 was chemically phosphorylated using phosphoramidate. Excess phosphoramidate was removed by anion exchange chromatography using a micro spin column. After incubation of the eluate with PHPT1, the removed phosphate was bound on a consecutive anion exchange spin column. The eluate was assayed in a micro plate format for remaining phosphate in the substrate Ac-Val-Arg-Leu-Lys-His(P)-Arg-Lys-Leu-Arg-pNA. Histone H4, also highly positive in charge, was subjected to the same procedure to explore the possibility to use other substrates to PHPT1 in this assay format. Results. It was found that Ac-Val-Arg-Leu-Lys-His(P)-Arg-Lys-Leu-Arg-pNA and phosphohistone H4 were dephosphorylated by PHPT1. The apparent K(m) for Ac-Val-Arg-Leu-Lys-His(P)-Arg-Lys-Leu-Arg-pNA was in the order of 10 mu M. Using this method, phosphohistidine phosphatase activity was detected in mouse liver cell sap with Ac-Val-Arg-Leu-Lys-His(P)-Arg-Lys-Leu-Arg-pNA as substrate. Discussion. The described method for determination of PHPT1 activity is comparably much easier and faster than presently used methods for detection of phosphohistidine phosphatase activity. It is also sensitive, since the lower activity limit was 5 pmol phosphate released per min. It has the potential to be used both for more rapid screening for inhibitors and activators to phosphohistidine phosphatases and for screening of histidine kinases.
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| 2. |
- Cox Eriksson, Christine, 1956-
(författare)
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Children's Vocabulary Development : The role of parental input, vocabulary composition and early communicative skills
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this thesis is to examine the early vocabulary development of a sample of Swedish children in relation to parental input and early communicative skills. Three studies are situated in an overall description of early language development in children. The data analyzed in the thesis was collected within a larger project at Stockholm University (SPRINT- “Effects of enhanced parental input on young children’s vocabulary development and subsequent literacy development” [VR 2008-5094]).Data analysis was based on parental report via SECDI, the Swedish version of the MacArthur-Bates Communicative Development Inventories, and audio recordings. One study examined parental verbal interaction characteristics in three groups of children with varying vocabulary size at 18 months. The stability of vocabulary development at 18 and 24 months was investigated in a larger study, with focus on children’s vocabulary composition and grammatical abilities. The third study examined interrelations among early gestures, receptive and productive vocabulary, and grammar measured with M3L, i.e. three longest utterances, from 12 to 30 months.Overall results of the thesis highlight the importance of early language development. Variability in different characteristics in parental input is associated with variability in child vocabulary size. Children with large early vocabularies exhibit the most stability in vocabulary composition and the earliest grammatical development. Children’s vocabulary composition may reflect individual stylistic variation. Use of early gestures is associated differentially with receptive and productive vocabulary.Results of the thesis have implications for parents, child- and healthcare personnel, as well as researchers and educational practitioners. The results underscore the importance of high quality in adult-child interaction, with rich input fine-tuned to children’s developmental levels and age, together with high awareness of early language development.
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| 3. |
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| 4. |
- Baeckström, Dan, 1956, et al.
(författare)
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Expression of the leukocyte-associated sialoglycoprotein CD43 by a colon carcinoma cell line
- 1995
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Ingår i: Journal of Biological Chemistry. - : Elsevier BV. - 0021-9258. ; 270, s. 13688-13692
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Tidskriftsartikel (refereegranskat)abstract
- The colon adenocarcinoma cell line COLO 205 secretes L-CanAg, a mucin- like glycoprotein carrying the carcinoma-associated sialyl-Lewis a carbohydrate epitope. In an attempt to identify its apoprotein, an NH2- terminal peptide sequence was obtained from purified L-CanAg. In all interpretable positions, this sequence showed 100% identity to the NH2- terminal of human CD43 (leukosialin, sialophorin), a plasma membrane-bound sialoglycoprotein hitherto only identified in leukocytes and other hematopoietic cells. An antiserum against deglycosylated L-CanAg and an anti- CD43 antiserum both immunoprecipitated a 61-kDa band, interpreted as the CD43 precursor, from COLO 205 cells as well as from the known CD43-expressing cell line HL-60. Results from immunoprecipitations following pulse-chase experiments and tunicamycin treatments were in agreement with earlier studies on the CD43 precursor. RNA blot analysis confirmed the expression of CD43 by the COLO 205 cell line, whereas three other colon carcinoma cell lines were negative. The glycosylation-dependent monoclonal antibody Leu-22, which recognizes leukocyte CD43, failed to bind L-CanAg, probably due to its much more extensive glycosylation. We conclude that L-CanAg is the secreted extracellular domain of a novel glycoform of CD43 and that CD43, if expressed in other carcinoma cells, may have escaped notice in studies relying on glycosylation-dependent monoclonal antibodies against leukocyte CD43.
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| 5. |
- Beckman Sundh, Ulla, 1953-
(författare)
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Studies on Phosphohistidine Phosphatase 1 : What? Where? Why?
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Phosphohistidine phosphatase 1 (PHPT1) is a small protein, consisting of 125 amino acids, that catalyzes the dephosphorylation of histidine but does not have any activity towards other phosphorylated amino acids. PHPT1 was identified in 2002, and is so far the only mammalian histidine phosphatase known, but still little is known about its physiological role. No mammalian histidine kinases have hitherto been identified.Phosphorylation is one of the most important ways in which the structure and activity of a protein may be changed after translation. Proteins are phosphorylated on the side chain of amino acid residues. When a hydroxyl is phosphorylated the result is a phosphoester and when a nitrogen is phosphorylated the result is a phosphoamidate. Histidine may be phosphorylated on either of the two nitrogens of the imidazole ring of the side chain. The resulting phosphoamidate bond is labile and rich in energy, which makes histidine phosphorylation highly reversible and flexible. However, histidine phosphorylation is less studied than that of the phosphoesters due to the acid lability of the phosphoamidate bond.The work described in this thesis was focused on further elucidating the physiological role of PHPT1. Amino acid residues of importance for the activity of PHPT1 were identified, and mutants with decreased phosphatase activity were produced. These mutants have been used in studies on the function of PHPT1. By using immunohistochemical methodology the localization of PHPT1 in both mouse and human tissues was determined, with mainly similar results. A general finding was that expression of PHPT1 was high in epithelial cells with short turnover time, indicating that PHPT1 may have an important role in proliferating cells. We have also developed a comparatively fast and simple screening method for determination of PHPT1 activity. Since research in this field has been hampered by the lack of efficient and practical methodology, hopefully this new method will be an asset in search of inhibitors for PHPT1, which in turn may be used for detection of the elusive mammalian histidine kinases, the finding of which may give major breakthroughs in the field.
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| 6. |
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| 7. |
- Blomqvist, My, et al.
(författare)
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Cognitive ability and dental fear and anxiety
- 2013
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Ingår i: European Journal of Oral Sciences. - : Wiley. - 0909-8836 .- 1600-0722. ; 121:2, s. 117-120
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Tidskriftsartikel (refereegranskat)abstract
- Dental fear and anxiety (DFA), as well as dental behavior management problems, are common in children and adolescents. Several psychological factors in the child, and parental DFA, have been studied and found to correlate to the child's DFA. The aim of this study was to investigate the relationship between cognitive ability and DFA in a population-based group of children with identified behavior and learning problems. In conjunction with a dental examination at 11yr of age, 70 children were assessed with regard to DFA using the Children's Fear Survey Schedule Dental Subscale (CFSS-DS), and their cognitive ability was assessed using the Wechsler Intelligence Scale for Children. In addition, parental DFA was measured using the Corah Dental Anxiety Scale. The results revealed that DFA was significantly correlated to verbal intelligence quotient (IQ) but not to any other cognitive index. A significant correlation was found between parental DFA and child DFA. The results indicate that the child's verbal capacity may be one factor of importance in explaining dental fear in children.
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| 8. |
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| 9. |
- Blomqvist, My, et al.
(författare)
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Dental caries in adolescents with attention deficit hyperactivity disorder: a population-based follow-up study.
- 2011
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Ingår i: European Journal of Oral Sciences. - : Wiley. - 1600-0722 .- 0909-8836. ; 119:5, s. 381-385
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Tidskriftsartikel (refereegranskat)abstract
- This study tested the hypothesis that adolescents with attention deficit hyperactivity disorder (ADHD) exhibit a higher prevalence of caries than adolescents in a control group. Thirty-two adolescents with ADHD and a control group of 55 adolescents from a population-based sample, all 17yr of age, underwent a clinical and radiographic dental examination. The mean±SD number of decayed surfaces (DS) was 2.0±2.2 in adolescents with ADHD and 0.9±1.4 in adolescents of the control group. Thirty-one per cent of the adolescents in the ADHD group had no new caries lesions (DS=0) compared with 62% in the control group. Six per cent of the adolescents in the ADHD group were caries free [decayed, missing or filled surfaces (DMFS)=0] compared with 29% in the control group. Adolescents with ADHD also had a higher percentage of gingival sites that exhibited bleeding on probing compared with the control group: 35±39% vs. 16±24% (mean±SD), respectively. At 17yr of age, adolescents with ADHD exhibited a statistically significantly higher prevalence of caries compared with an age-matched control group. Adolescents with ADHD need more support regarding oral hygiene and dietary habits. They should be followed up with shorter intervals between dental examinations to prevent caries progression during adulthood.
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| 10. |
- Blomqvist, My, et al.
(författare)
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How do children with attention deficit hyperactivity disorder interact in a clinical dental examination? : A video analysis.
- 2005
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Ingår i: European Journal of Oral Sciences. - : Wiley. - 0909-8836 .- 1600-0722. ; 113:3, s. 203-209
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Tidskriftsartikel (refereegranskat)abstract
- Attention deficit hyperactivity disorder (ADHD) is currently the most common behavioural disorder in school-age children. The aim of this study was to perform a detailed analysis of behavioural interactions between the dentist and the child patient with ADHD. All children born in 1991(n=555) in one Swedish municipality were screened for attention and learning problems and assessed for ADHD: Twenty-two children with ADHD and a control group of 47 children without attention and learning problems were included in the study. The dental recall visit was recorded on video. The interaction between the dentist and the child was analyzed in detail and scored as verbal and nonverbal initiatives and responses. Compared to the children in the control group, the children with ADHD made significantly more initiatives, especially initiatives that did not focus on the eaxmination or the dentist. The children with ADHD had fewer verbal responses and more missing responses. In conclusion, the problems in communication resulted in less two-way communication between the dentist and the children with ADHD than the interaction between the dentist and the children in the control group. The children with ADHD had particular difficulties staying focused on the examination.
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