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M Berg

Publications and source records attributed to M Berg.

At least 37 records · Page 2Linked to original sources
PubMed2002

Humoral immune response against Borna disease virus (BDV) in experimentally and naturally infected cats.

In order to investigate the peripheral and intracerebral humoral immune response against Borna disease virus (BDV) in cats, serum and cerebrospinal fluid (CSF) samples from experimentally and naturally BDV-infected cats were analysed in two different test systems (indirect enzyme-linked immunosorbent assay and indirect immunofluorescent test). The experimentally infected cats developed high antibody titres against the major immunogenic BDV-proteins, p24 and p40. In contrast, the naturally infected cats showed a comparatively weak humoral immune response. The experimentally infected cats were inoculated with either BDV laboratory strain V or a feline BDV-isolate. Some differences existed between the two groups of cats. The former group developed a higher response against p40, whereas the latter group showed, beside the p40-response, a more pronounced p24-response, similar to the situation in the naturally infected cats.

Animals↗
PubMed2002

The theory of use behind telemedicine: how compatible with physicians' clinical routines?

Since the early 1990s, telemedicine, or the use of information technology to support the delivery of health care from a distance, has increasingly gained the support of clinicians, administrators and policymakers across industrialised countries. However, the "theory of use" behind telemedicine-its rationale and the manner in which clinicians are expected to use it in their daily activities--has been only marginally investigated. In this paper we present the results of a qualitative study which examines the theory of use behind teleconsultation from the viewpoint of physicians (n = 37) in six specialities, practising in Quebec (Canada) hospitals. We employ Giddens' Structuration Theory (1984) to analyse the views, communications needs and referral strategies of physicians. Two questions are explored: (1) To what extent can teleconsultation be integrated into the routines of diverse medical specialities'? and (2) Why and how might clinicians use this technology? Our research indicates that specialities relying on either thorough physical examinations or specialised investigative techniques are unlikely to restructure their work routines to accommodate teleconsultation, which they view as limited. Specialities that primarily exploit images or numerical data tend to perceive teleconsultation as more useful. The perceived enabling properties of teleconsultation increase as a function of the distance the patient would have to travel to be seen directly by a consultant. The constraining properties are linked to the type of information transmitted, since physicians believe that only objective data can be safely consulted from a distance, whereas relying on the remote physician's interpretation of subjective information is deemed inappropriate. We thus conclude that the development of teleconsultation should be consolidated around applications whose theory of use is compatible with existing clinical routines, or offers opportunities to restructure clinical work according to the needs of providers and remote communities.

Attitude of Health Personnel↗
PubMed2001

Structural basis for pterin antagonism in nitric-oxide synthase. Development of novel 4-oxo-pteridine antagonists of (6R)-5,6,7,8-tetrahydrobiopterin.

Pathological nitric oxide (NO) generation in sepsis, inflammation, and stroke may be therapeutically controlled by inhibiting NO synthases (NOS). Here we targeted the (6R)-5,6,7,8-tetrahydro-l-biopterin (H(4)Bip)-binding site of NOS, which, upon cofactor binding, maximally increases enzyme activity and NO production from substrate l-arginine. The first generation of H(4)Bip-based NOS inhibitors employed a 4-amino pharmacophore of H(4)Bip analogous to antifolates such as methotrexate. We developed a novel series of 4-oxo-pteridine derivatives that were screened for inhibition against neuronal NOS (NOS-I) and a structure-activity relationship was determined. To understand the structural basis for pterin antagonism, selected derivatives were docked into the NOS pterin binding cavity. Using a reduced 4-oxo-pteridine scaffold, derivatives with certain modifications such as electron-rich aromatic phenyl or benzoyl groups at the 5- and 6-positions, were discovered to markedly inhibit NOS-I, possibly due to hydrophobic and electrostatic interactions with Phe(462) and Ser(104), respectively, within the pterin binding pocket. One of the most effective 4-oxo compounds and, for comparisons an active 4-amino derivative, were then co-crystallized with the endothelial NOS (NOS-III) oxygenase domain and this structure solved to confirm the hypothetical binding modes. Collectively, these findings suggest (i) that, unlike the antifolate principle, the 4-amino substituent is not essential for developing pterin-based NOS inhibitors and (ii), provide a steric and electrostatic basis for their rational design.

Animals↗
PubMed2001

Characterization of Spiroplasma citri adhesion related protein SARP1, which contains a domain of a novel family designated sarpin.

Transmission of the plant pathogen Spiroplasma citri by its leafhopper vector, Circulifer tenellus, involves adherence to and invasion of insect host cells. The S. citri adhesion related protein P89 (SARP1) was purified by immunoprecipitation using anti-SARP1 monoclonal antibodies. The protein's N-terminal amino acid sequence was determined and used to design a degenerate oligonucleotide. The labeled oligonucleotide hybridized to a 3.5 kb MboI fragment from S. citri DNA, which was then cloned and sequenced. Additionally, a 1.9 kb RsaI fragment of S. citri DNA, partially overlapping the MboI fragment, was isolated and characterized. Sequence analysis of the two clones revealed four open reading frames. ORF1 (675 bp) encodes the C-terminal part of a Soj-like protein. ORFs 1 and 2 were separated from ORFs 3 and 4 by a putative transcription termination site, indicated by a hairpin structure. ORF3 encodes an amphiphilic 798 amino acid long protein with a cleavable signal peptide and a predicted transmembrane helix near the C-terminus. The mature protein of 85.96 kDa has a calculated pI value of 5.5 and has an N-terminal amino acid sequence consistent with that determined from the purified SARP1. At the N-terminus of this protein is a region consisting of six repeats, each 39-42 amino acids, a motif belonging to a previously unrecognized family of repeats found in a variety of bacterial proteins. The taxonomically spotty presence of this 'sarpin' domain and the relationship of the repeats to each other suggests a convergent evolution in multiple lineages.

Amino Acid Sequence↗
PubMed2001

Mutations in the X-linked filamin 1 gene cause periventricular nodular heterotopia in males as well as in females.

Periventricular heterotopia (PH) is a human neuronal migration disorder in which many neurons destined for the cerebral cortex fail to migrate. Previous analysis showed heterozygous mutations in the X-linked gene filamin 1 (FLN1), but examined only the first six (of 48) coding exons of the gene and hence did not assess the incidence and functional consequences of FLN1 mutations. Here we perform single-strand conformation polymorphism (SSCP) analysis of FLN1 throughout its entire coding region in six PH pedigrees, 31 sporadic female PH patients and 24 sporadic male PH patients. We detected FLN1 mutations by SSCP in 83% of PH pedigrees and 19% of sporadic females with PH. Moreover, no PH females (0/7 tested) with atypical radiographic features showed FLN1 mutations, suggesting that other genes may cause atypical PH. Surprisingly, 2/24 males analyzed with PH (9%) also carried FLN1 mutations. Whereas FLN1 mutations in PH pedigrees caused severe predicted loss of FLN1 protein function, both male FLN1 mutations were consistent with partial loss of function of the protein. Moreover, sporadic female FLN1 mutations associated with PH appear to cause either severe or partial loss of function. Neither male could be shown to be mosaic for the FLN1 mutation in peripheral blood lymphocytes, suggesting that some neurons in the intact cortex of PH males may be mutant for FLN1 but migrate adequately. These results demonstrate the sensitivity and specificity of DNA testing for FLN1 mutations and have important functional implications for models of FLN1 protein function in neuronal migration.

Abnormalities, Multiple↗
PubMed2001

Sorption and desorption behavior of organotin compounds in sediment-pore water systems.

Sediments contaminated with organotin compounds (OTs), in particular triorganotins (TOTs), are abundant in areas with high shipping activities. To assess the possible remobilization of these highly toxic compounds from such sediments, a profound understanding of their sorption/desorption behavior is necessary. In this work the extent and reversibility of sorption of OTs to sediments has been investigated using contaminated freshwater harbor sediments and two certified OT containing marine sediments. Experiments conducted with perdeuterated OTs showed that sorption of OTs to sediments is a fast and reversible process involving primarily particulate organic matter (POM) constituents as sorbents. The organic carbon-normalized sediment-water distribution ratios (DOC, expressed in L/kgOC) determined in the laboratory were consistent with in-situ DOCs obtained from OT concentrations measured in sediment and pore water samples from two dated sediment cores. For both butyl- and phenyltin compounds the log DOC values were in the range of 4.7-6.1, and the following sequence was observed: DOC (tri-OT) > or = DOC (di-OT) > or = DOC (mono-OT). However, the differences were much less pronounced than would have been expected for hydrophobic partitioning of the corresponding compounds into POM. These results support our hypothesis from earlier work with dissolved humic acids that OT sorption to sediments occurs primarily by reversible formation of (innerspere) complexes between the tin atom and carboxylate and phenolate ligands present in POM. Because of the high DOC values (i.e. log DOC > or = 4) the diffusion of OTs from deeper sediments to the surface will be rather slow, and thus a major release from undisturbed sediments is not expected. However, because OTs readily desorb, any resuspension of contaminated sediments (e.g., by the tide, storms or dredging activities) will lead to enhanced OT concentrations in the overlaying water column. Furthermore, in contrastto polycyclic aromatic hydrocarbons (PAH) where large fractions may be tightly bound (in)to soot or other carbonaceous materials, OTs will be more readily bioavailable due to the fast and reversible sorption/desorption behavior.

Absorption↗
PubMed2001

Arsenic contamination of groundwater and drinking water in Vietnam: a human health threat.

This is the first publication on arsenic contamination of the Red River alluvial tract in the city of Hanoi and in the surrounding rural districts. Due to naturally occurring organic matter in the sediments, the groundwaters are anoxic and rich in iron. With an average arsenic concentration of 159 micrograms/L, the contamination levels varied from 1 to 3050 micrograms/L in rural groundwater samples from private small-scale tubewells. In a highly affected rural area, the groundwater used directly as drinking water had an average concentration of 430 micrograms/L. Analysis of raw groundwater pumped from the lower aquifer for the Hanoi water supply yielded arsenic levels of 240-320 micrograms/L in three of eight treatment plants and 37-82 micrograms/L in another five plants. Aeration and sand filtration that are applied in the treatment plants for iron removal lowered the arsenic concentrations to levels of 25-91 micrograms/L, but 50% remained above the Vietnamese Standard of 50 micrograms/L. Extracts of sediment samples from five bore cores showed a correlation of arsenic and iron contents (r2 = 0.700, n = 64). The arsenic in the sediments may be associated with iron oxyhydroxides and released to the groundwater by reductive dissolution of iron. Oxidation of sulfide phases could also release arsenic to the groundwater, but sulfur concentrations in sediments were below 1 mg/g. The high arsenic concentrations found in the tubewells (48% above 50 micrograms/L and 20% above 150 micrograms/L) indicate that several million people consuming untreated groundwater might be at a considerable risk of chronic arsenic poisoning.

Arsenic↗
PubMed2001

On-line flow sample stacking in a flow injection analysis-capillary electrophoresis system: 2000-fold enhancement of detection sensitivity for priority phenol pollutants.

A flow injection analysis-capillary electrophoresis system has been used for on-line flow stacking of 11 US Environmental Protection Agency priority phenol pollutants. Samples containing low concentrations of phenols dissolved in deionised water are continuously delivered to the capillary opening by means of a peristaltic pump. The sample components stack at the boundary between the highly conductive separation electrolyte and the introduced sample. By selecting an appropriate electrolyte and stacking conditions the movement of the electrolyte solution inside the capillary can be reduced, thereby improving the stacking efficiency. The electrolyte used here contained 20 mM phosphate, 8% 2-butanol, and 0.001% hexamethonium bromide at pH 11.95, and the stacking was carried out at 2 kV for 240 s. These conditions allowed up to 2000-fold preconcentration of the selected phenols. No matrix removal was necessary.

Electrophoresis, Capillary↗
PubMed2001

The plasmid pcDNA3 differentially induces production of interferon-alpha and interleukin-6 in cultures of porcine leukocytes.

An adjuvant effect of invertebrate DNA has been attributed to its relative high frequency of unmethylated CpG dinucleotides. Here we describe the interferon-alpha (IFN-alpha) and interleukin-6 (IL-6) inducing properties of a commonly used eukaryotic expression vector, pcDNA3, in porcine leukocytes. The magnitude of the cytokine response was compared to that induced by the synthetic ds RNA analogue poly(I):poly(C), inactivated preparations of Aujeszky's disease virus (ADV) and the Gram-negative bacteria Actinobacillus pleuropneumoniae. The plasmid, as well as poly(I):poly(C), required lipofectin to induce IFN-alpha production whereas both preparations induced IL-6 irrespective of preincubation with lipofectin. However, the nucleic acid-induced levels of IL-6 were low compared to those induced by A. pleuropneumoniae. The IFN-alpha response elicited by pcDNA3 in the presence of lipofectin was as high as, or higher than that induced by ADV. Interestingly, also A. pleuropneumoniae induced a substantial production of IFN-alpha when preincubated with lipofectin. Plasmid expression was not necessary for induction of IFN-alpha. Furthermore, the IFN-alpha inducing capacity of pcDNA3 was not reduced when the two predicted immunostimulatory sequences 5'AACGTT3' were deleted. Nor did the ability of the plasmid to induce IFN-alpha production decrease when the ampicillin resistance (ampR) gene was replaced with the kanamycin resistance (kanR) gene. However, methylation of all cytidines in CpG dinucleotides of pcDNA3 abolished the IFN-alpha inducing capacity. These in vitro results indicate an immunomodulatory role of bacterial DNA also in the pig. Unmethylated CpG dinucleotides are crucial for induction of IFN-alpha by the plasmid, but other CpG motifs than those within the 5'AACGTT3' sequences of the ampR gene contribute to this induction in porcine cells.

Actinobacillus pleuropneumoniae↗
PubMed2001

Low CD4(+) T cell responses to the C-terminal region of the malaria merozoite surface protein-1 may be attributed to processing within distinct MHC class II pathways.

The C-terminal fragment of merozoite surface protein-1 (MSP-1) of the mouse malaria parasite Plasmodium chabaudi chabaudi (AS) stimulates a weak CD4 T cell response when compared to the response to a more structurally simple region of the molecule. The tertiary structure of the C-terminal region of MSP-1 is maintained by five disulfide bonds. A peptide from this region could only be processed and loaded onto newly synthesized MHC class II molecules, whereas a peptide from the structurally simple region was available for loading onto recycling MHC class II. CD4(+) T cell hybridomas took longer to recognize an epitope derived from the disulfide-bonded region whether native parasite or recombinant MSP-1 antigen was used. Reduction of disulfide bonds in the C-terminal region subsequently allowed peptides to be loaded onto recycling MHC class II and greatly enhanced the rapidity of the T cell response. These data demonstrate that differential processing occurs intramolecularly in MSP-1, which may be responsible for the observed weak CD4 T cell responses against this region. The consequences of this in vivo may be that limited T cell help is available for protective antibody production which has important implications for designing vaccines based on MSP-1.

Alkylation↗
PubMed2001

Isolation, expression, and characterization of fully functional nontoxic BiP/GRP78 mutants.

Mammalian BiP/GRP78 and Escherichia coli DnaK belong to the highly conserved hsp70 family and function as molecular chaperones in the endoplasmic reticulum or the cytosol, respectively. Induction of murine BiP/GRP78 expression in E. coli leads to growth arrest and cell death, independent of the bacterial strain and vector used. Analysis of various BiP constructs and mutants shows that the dominant-lethal phenotype is induced specifically by the expression of the 13.7-kDa C-terminal domain and abolished by a single substitution in that region. Deletion of that region also results in nontoxic gene products that can be overexpressed and purified to homogeneity. The nontoxic mutants are highly expressed in E. coli, representing up to 20% of the soluble fraction. They are catalytically active, depolymerize upon binding ATP or synthetic peptide, and interact with the J-domain of the DnaJ-like accessory protein, MTJ1, with near wild-type affinity. Our data indicate that the cytotoxic effect encountered during overexpression of recombinant proteins can be caused by a single domain and can be alleviated by a specific mutation or deletion in that region without altering the catalytic properties of the enzyme.

Adenosine Triphosphatases↗
PubMed2001

Three decades of sociomedical experiences from West Swedish Rett females 4-60 years of age.

Rett syndrome, today known as a worldwide important cause behind severe mental retardation in females, has been seen in Sweden since the 1960s (the senior author). This study gives population representative clinical and sociomedical follow-up data from West Sweden (1/4 of the population in Sweden). The series comprises 54 females diagnosed in 1971-1998, 5-60 years old, median age 20. Mortality in 1971-2000 was 18% (10/54), median age at death 20. Death usually had been sudden and unexpected. The sociomedical follow-up emphasized the adult group. The large majority had usually moved to small group homes, a good and well-accepted environment once the staff had learned the particularities of these so uniquely neurodevelopmentally disabled women.

Adolescent↗
PubMed2001

Rett syndrome: update of a 25 year follow-up investigation in Western Sweden--sociomedical aspects.

Through 1998-1999 the Swedish research team have systematically mapped 45 of 54 females with Rett syndrome (RS) aged 5-57 years (Berg M. Uppföljning av flickor med Rett syndrom i Västsverige. Socialmedicinsk kartläggning, Stencilerad rapport, Sahlgrenska universitetssjukhuset, Göteborg, 1999; Läkartidningen (Swedish Medical Journal) 96 (1999) 5488). The emphasis is on the RS females' adjustment to grown-up living. At an adult age the large majority moved over to a Swedish type of small group home. We visited these girls in their group homes and got information about their adaptation to this special home situation. We noted their behaviour and contact with the staff and interviewed their parents. The results showed that the young women usually had adjusted well. The adjustment seemed to depend on the degree of planning before the girls moved from their parents to special group homes. These seem to provide a good environment for the RS females, in respect of both physical and social aspects. Although neuropaediatrics in Sweden today has advanced in RS knowledge, the result from this research shows that in Swedish society there is still a great ignorance of RS, even among medical professionals. In particular there is a gap of knowledge when the medical responsibility had to be transferred over to adult medicine. Many of the parents emphasized the great importance of how they were listened to by professionals in public medical and social services. It is essential that professionals always listen to information from parents and personal assistants.

Adaptation, Psychological↗
PubMed2001

Meeting patients' needs with patient information systems: potential benefits of qualitative research methods.

This article reports on our pilot evaluation of an electronic patient information system for children with amblyopia and their parents. The aim was to investigate whether the information system would be able to improve the quality of care, as indicated by an improvement in the effectiveness and efficiency of care, and in an increase in patient satisfaction. In the pilot evaluation, we used qualitative research methods, exploring the impact of the information system on children and their parents, with the aim to find suitable indicators for a potential further, quantitative study. Yet we found that the system was little used and had marginal effects on the quality of care for children with amblyopia and their parents. It appeared that the main problem underlying this patient information system was that the needs of those people who actually would be using the system had never really been investigated. The designers had built their assumptions about these needs into the system. These appeared to be mistaken at so many levels that the system could not become a success. As a result of this pilot evaluation, the patient information project was thoroughly transformed. This study makes clear that a thorough exploration of user needs before building the system, using qualitative research methods, may be crucial because it can prevent mismatches and maximizes the chance that the eventual information system meets its most important aim: to enhance patient empowerment and improve the quality of care.

Amblyopia↗
PubMed2001

Implementing information systems in health care organizations: myths and challenges.

Successfully implementing patient care information systems (PCIS) in health care organizations appears to be a difficult task. After critically examining the very notions of 'success' and 'failure', and after discussing the problematic nature of lists of 'critical success- or failure factors', this paper discusses three myths that often hamper implementation processes. Alternative insights are presented, and illustrated with concrete examples. First of all, the implementation of a PCIS is a process of mutual transformation; the organization and the technology transform each other during the implementation process. When this is foreseen, PCIS implementations can be intended strategically to help transform the organization. Second, such a process can only get off the ground when properly supported by both central management and future users. A top down framework for the implementation is crucial to turn user-input into a coherent steering force, creating a solid basis for organizational transformation. Finally, the management of IS implementation processes is a careful balancing act between initiating organizational change, and drawing upon IS as a change agent, without attempting to pre-specify and control this process. Accepting, and even drawing upon, this inevitable uncertainty might be the hardest lesson to learn.

Delivery of Health Care↗
PubMed2001

Wild birds as a possible natural reservoir of Borna disease virus.

The natural reservoir of Borna disease virus (BDV) is unknown. In this paper, we show that mallards (Anas platyrhyncos) and jackdaws (Corvus monedula) can be subclinically infected carriers of this virus. From faecal samples collected at a bird pond, we were able to amplify fragments of the BDV p24 and p40 genes. Following cloning and sequencing, a phylogenetic analysis revealed that these birds carry strains of BDV closely related to but distinct from the reference strains BDV V and He/80. To our knowledge, this is the first confirmed finding of BDV in wild birds.

Animals↗
PubMed2001

Guidelines for appropriate care: the importance of empirical normative analysis.

The Royal Dutch Medical Association recently completed a research project aimed at investigating how guidelines for 'appropriate medical care' should be construed. The project took as a starting point that explicit attention should be given to ethical and political considerations in addition to data about costs and effectiveness. In the project, two research groups set out to design guidelines and cost-effectiveness analyses (CEAs) for two circumscribed medical areas (angina pectoris and major depression). Our third group was responsible for the normative analysis. We undertook an explorative, qualitative pilot study of the normative considerations that played a role in constructing the guidelines and CEAs, and simultaneously interviewed specialists about the normative considerations that guided their diagnostic and treatment decisions. Explicating normative considerations, we argue, is important democratically: the issues at stake should not be left to decision analysts and guideline developers to decide. Moreover, it is a necessary condition for a successful implementation of such tools: those who draw upon these tools will only accept them when they can recognize themselves in the considerations implied. Empirical normative analysis, we argue, is a crucial tool in developing guidelines for appropriate medical care.

Angina Pectoris↗