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Biomedical subjects

C Persson

Publications and source records attributed to C Persson.

At least 37 records · Page 2Linked to original sources
PubMed1999

[CATCH22 or 22q11 deletion syndrome. An underdiagnosed and misunderstood disease category with a variable clinical picture].

Patients with CATCH 22 or 22q11 deletion syndrome constitute a fast growing category in Sweden as it is still underdiagnosed. In a series of 54 patients the predominant features were found to be speech and language difficulties, cardiac malformations, susceptibility to infection, learning and behavioural problems, hypoparathyroidism, minor motor deficits, and characteristic facies. The severity of these problems varied individually, but as the patients had numerous symptoms and disabilities the overall degree of handicap was considerable. Thus, regular evaluation of the patient's condition and overall need of care is important.

Adolescent↗
PubMed1999

YopH dephosphorylates Cas and Fyn-binding protein in macrophages.

The tyrosine phosphatase YopH is an essential virulence effector of pathogenic Yersinia spp. YopH, which is translocated from extracellularly located bacteria into interacting target cells, blocks phagocytosis by professional phagocytes. We show here that immunoprecipitation of YopH from lysates of J774 cells infected with Y. pseudotuberculosis expressing an inactive form of YopH resulted in co-precipitation of certain phosphotyrosine proteins. The association between the inactive YopH and phosphotyrosine proteins in the 120 kDa range was rapid and could be detected after 2 min of infection. The proteins were identified as the docking proteins Cas and Fyn-binding protein (FYB). Upon infection of J774 cells with Y. pseudotuberculosis lacking YopH expression both of these proteins became tyrosine phosphorylated. Moreover, this infection caused recruitment of Cas to peripheral focal complexes, and FYB was relocalized to areas surrounding these structures. Both Cas and FYB became dephosphorylated upon infection with Y. pseudotuberculosis expressing active YopH, and this was associated with disruption of focal complexes. With regard to the previous identification of Cas and focal complexes as targets of YopH in HeLa cells, the present study supports an important role for these targets in a general mechanism of bacterial uptake.

Bacterial Outer Membrane Proteins↗
PubMed1999

The Swedish version of the patient-generated subjective global assessment of nutritional status: gastrointestinal vs urological cancers.

PURPOSE: To translate and evaluate the Patient-Generated Subjective Global Assessment (PG-SGA) a method for the assessment of nutritional status. METHOD: Eighty-seven patients with gastrointestinal and urological tumours completed four sections and the remaining sections were independently completed by a doctor and a dietician. Patients were classified as SGA A (well nourished), SGA B (moderately/suspected of being malnourished) or SGA C (severely malnourished). RESULTS: Interobserver agreement was complete in 90% of the cases. More patients with gastrointestinal cancers than with urological cancers were classified as SGA B and C. Mean levels of S-albumin and P-prealbumin differed between the SGA-classes. Multivariate logistic regression analyses showed independent contributions to the overall classification by weight loss in the last 6 months, level of food intake, problems with eating, physical activity and muscle wastage. Survival was significantly higher in SGA A than in SGA B+C, P < 0.001. CONCLUSION: The PG-SGA is useful for the assessment of nutritional status. Patients had no problems in answering the questions. The PG-SGA also carried prognostic information.

Adult↗
PubMed1999

Localization of the Yersinia PTPase to focal complexes is an important virulence mechanism.

The protein tyrosine phosphatase YopH, produced by the pathogen Yersinia pseudotuberculosis, is an essential virulence determinant involved in antiphagocytosis. Upon infection, YopH is translocated into the target cell, where it recognizes focal complexes. Genetic analysis revealed that YopH harbours a region that is responsible for specific localization of this PTPase to focal complexes in HeLa cells and professional phagocytes. This region is a prerequisite for blocking an immediate-early Yersinia-induced signal within target cells. The region is also essential for antiphagocytosis and virulence, illustrating the biological significance of localization of YopH to focal complexes during Yersinia infection. These results also indicate that focal complexes play a role in the general phagocytic process.

Animals↗
PubMed1998

Role of immunoglobulin-like domains 2-4 of the platelet-derived growth factor alpha-receptor in ligand-receptor complex assembly.

Platelet-derived growth factor (PDGF) is a dimeric protein that exerts its effects through tyrosine kinase alpha- and beta-receptors. The extracellular part of each receptor is composed of five Ig-like domains. Recombinant forms of alpha-receptor domains 1-4 (alphaRD1-4), 1-3 (alphaRD1-3), and 1 and 2 (alphaRD1-2) were prepared after expression in Chinese hamster ovary cells and were used to study the assembly of soluble ligand-receptor complexes. When incubated with micromolar concentrations of PDGF, both alphaRD1-3 and alphaRD1-4 formed complexes of 1:2 molar composition, i.e. one dimeric PDGF molecule bound two soluble receptors. alphaRD1-3, in contrast to alphaRD1-4, formed detectable 1:1 complexes under conditions of ligand excess. alphaRD1-4 displayed an increased ability to form 1:2 complexes as compared with alphaRD1-3 under conditions of limiting concentrations of ligand. We thus conclude that Ig-like domain 4-mediated receptor-receptor interactions contribute to 1:2 PDGF.alphaRD1-4 complex formation. Since alphaRD1-4 and alphaRD1-3 were equipotent in blocking binding of subnanomolar concentrations of PDGF to cell-surface receptors, we also conclude that this effect is predominantly achieved through formation of Ig-like domain 4-independent 1:1 ligand-receptor complexes. Finally, since alphaRD1-2 bound PDGF-BB with high affinity, whereas PDGF-AA was bound only with low affinity, we conclude that Ig-like domain 3 of the PDGF alpha-receptor contains epitopes of particular importance for PDGF-AA binding and that most of the PDGF-BB-binding epitopes reside in Ig-like domains 1 and 2.

Animals↗
PubMed1998

Identification of a tissue- and differentiation stage-specific enhancer of the VpreB1 gene.

The VpreB and lambda 5 genes encode proteins that associate non-covalently to form the so-called surrogate light (SL) chain. The SL chain complexes with the immunoglobulin heavy chain to form the pre-B cell receptor, which plays a critical role in B cell development. Expression of the murine SL genes is regulated at the level of transcription initiation. Here, we show that a VpreB1 enhancer is located within the 356 bp immediately upstream of the coding sequence. Interestingly, this region exhibits 96% identity to the upstream region of VpreB2. Deletion mapping located the enhancer to between positions -214 and -47 (+1 is the 5'-most transcription initiation site). The enhancer is tissue and differentiation stage specific, and is composed of several DNA elements that are important for its activity. We also show that a transcription factor, early B cell factor, binds to two such elements, and that at least one of these sites is involved in determining enhancer activity.

Animals↗
PubMed1998

Bidirectional signaling between Yersinia and its target cell.

Preventing the early host immune defense allows pathogenic Yersinia to proliferate in lymphatic tissue. This ability depends on signaling that occurs between the bacteria and the host cells. Following intimate contact with the target cell a signal is generated within the bacterium that results in increased expression of virulence-associated proteins that are subsequently delivered into the infected cell. These proteins, designated Yops, interfere with the host-cell signaling pathways that are normally activated to eliminate infectious agents.

Humans↗
PubMed1998

Interview reliability for assessing mental work demands.

This study presented and evaluated an interview method for the analysis of tasks included in a work situation. What mental demands and possibilities do the work tasks give rise to? When was the work more or less automatic? When was use of active knowledge required? When were problem solving and planning needed? The study included an assessment of the interobserver reliability of the interviews with employees from 5 different careers: bus drivers (n = 10), home service workers (n = 32), carpenters (n = 11), farmers (n = 14), and teachers (n = 26). The extent to which this method can be reproduced in studies of different occupations is discussed. The interobserver reliability was good (.75-.82). There is support for the stability and usefulness of the interview for most types of work concerning the 3 categories of mental demands: routine, active knowledge, and problem solving/creativity.

Adult↗
PubMed1997

The PTPase YopH inhibits uptake of Yersinia, tyrosine phosphorylation of p130Cas and FAK, and the associated accumulation of these proteins in peripheral focal adhesions.

Pathogenic Yersinia resist uptake by eukaryotic cells by a mechanism involving the virulence protein YopH, a protein tyrosine phosphatase. We show that p130Cas and FAK are phosphorylated and recruited to peripheral focal complexes during bacterial uptake in HeLa cells. The inactive form of YopH interacts with the tyrosine phosphorylated forms of FAK and p130Cas and co-localizes with these proteins in focal adhesions. On the other hand, the presence of active YopH results in inhibition of uptake, dephosphorylation of p130Cas and FAK, and disruption of peripheral focal complexes. We suggest that p130Cas and FAK are substrates for YopH and that the dephosphorylation of these proteins impairs the uptake of Yersinia pseudotuberculosis into HeLa cells.

Bacterial Outer Membrane Proteins↗
PubMed1996

Identification of cross-reactive antigenic target regions for HIV type 1-specific antibody-dependent cellular cytotoxicity.

Monkey-derived hyperimmune antisera against 40 peptides, together representing the entire envelope gp120 of HIV-1LAI, were used to map antibody-dependent cellular cytotoxicity (ADCC) target regions. Four regions corresponding to amino acids 65-126, 152-230, 248-330, and 445-466 were found to contain epitopes inducing ADCC activity not only against HIV-1LAI-infected cells but also against cells infected with HIV-1SF2 and clinical isolates of HIV-1. When comparing seroreactivity to the individual peptides with ADCC titers none of the regions seemed to be dominant. These results thus describe cross-reactive regions involved in the functional immunity against HIV-1 gp120.

Amino Acid Sequence↗
PubMed1996

The YopB protein of Yersinia pseudotuberculosis is essential for the translocation of Yop effector proteins across the target cell plasma membrane and displays a contact-dependent membrane disrupting activity.

During infection of cultured epithelial cells, surface-located Yersinia pseudotuberculosis deliver Yop (Yersinia outer protein) virulence factors into the cytoplasm of the target cell. A non-polar yopB mutant strain displays a wild-type phenotype with respect to in vitro Yop regulation and secretion but fails to elicit a cytotoxic response in cultured HeLa cells and is unable to inhibit phagocytosis by macrophage-like J774 cells. Additionally, the yopB mutant strain was avirulent in the mouse model. No YopE or YopH protein were observed within HeLa cells infected with the yopB mutant strain, suggesting that the loss of virulence of the mutant strain was due to its inability to translocate Yop effector proteins through the target cell plasma membrane. Expression of YopB is necessary for Yersinia-induced lysis of sheep erythrocytes. Purified YopB was shown to have membrane disruptive activity in vitro. YopB-dependent haemolytic activity required cell contact between the bacteria and the erythrocytes and could be inhibited by high, but not low, molecular weight carbohydrates. Similarly, expression of YopE reduced haemolytic activity. Therefore, we propose that YopB is essential for the formation of a pore in the target cell membrane that is required for the cell-to-cell transfer of Yop effector proteins.

Animals↗