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Biomedical subjects

M Berg

Publications and source records attributed to M Berg.

At least 109 records · Page 6Linked to original sources
PubMed1998

Medical work and the computer-based patient record: a sociological perspective.

The computer-based patient record (CPR) is a tool likely to have great impact on the practice of medicine in the years to come. Yet, clinical settings with a fully integrated CPR are hard to find. This paper takes a sociological look at the attempts to construe and introduce CPRs. It is argued that part of the current trouble in getting these tools to work lies in the model of medical work that is inscribed in many (attempted) CPRs. A more sociological perspective on medical work should be able to offer points of departure for the construction of systems which might fit the needs of health care workers better. Based on participatory observation, the paper outlines what it is medical work comes down to from a sociological perspective, and how the medical record figures in this work. Finally, some consequences this depiction has for current discussions on and (proposed) implementations of CPRs are described.

Data Collection↗
PubMed1997

Sequence of a gene cluster from Malonomonas rubra encoding components of the malonate decarboxylase Na+ pump and evidence for their function.

Malonate decarboxylation in Malonomonas rubra involves the formation of malonyl-S-[acyl-carrier protein] from acetyl-S-[acyl-carrier protein] and malonate, carboxyltransfer to a biotin protein and its decarboxylation that is coupled to delta mu Na+ generation. The genes encoding components of the malonate decarboxylase enzyme system have been cloned and sequenced. These are located within a gene cluster of approximately 11 kb comprising 14 genes that have been termed madYZGBAECDHKFLMN in the given order. Upstream of madY an open reading frame pointing into the opposite direction of the mad genes was found with structural similarities to insertion-sequence elements. The upstream region also contains DNA regions which are typical for an Escherichia coli sigma 70 promoter. Within 950 bp downstream of madN no other open reading frame was found. This region contains a putative terminator sequence. The intergenic regions within the mad gene cluster are short (usually < 70 bp, maximum 302 bp) and ribosome binding sites were defined before all 14 genes. Thus, this DNA region could form a transcriptional unit and all 14 genes could be translated into proteins. The genes madABCDEF encode the structural proteins of the malonate decarboxylase as yet identified. By comparing protein and DNA sequences and by data bank searches for related proteins with known function the following assignments could be made: MadA represents the acyl-carrier-protein-transferase component. MadB is the integral membrane-bound carboxybiotin protein decarboxylase, MadC and MadD are the two subunits of the carboxyltransferase, MadE is the acyl carrier protein and MadF is the biotin protein. Sequence comparison further indicates that MadH could be involved in the acetylation of the phosphoribosyl-dephospho-CoA prosthetic group and MadG could be involved in its biosynthesis. MadL and MadM are membrane proteins that could function as malonate carrier. The function of the madY,Z,K and N gene products is as yet unknown.

Amino Acid Sequence↗
PubMed1997

Fc gamma receptor II dependency of enhanced presentation of major histocompatibility complex class II peptides by a B cell lymphoma.

Here we show that the B cell lymphoma A20.292 is capable of enhanced antigen presentation to CD4+ T cells in the presence of specific antibodies. This enhancement was inhibited by anti-Fc gamma receptor (R) antibodies, suggesting that it might be due to preferential uptake of the antigen/antibody complex through the Fc gamma RII receptor. However, immunoprecipitation studies revealed that the FcR of A20.292 cells was of the B cell type, Fc gamma RIIb1, which is not thought to be able to internalize antigen/antibody complexes via clathrin-coated pits. It was considered unlikely that A20.292 had an altered form of the B cell Fc gamma R (RIIb1) receptor that enabled internalization, since similar enhancing effects were also observed using an Fc gamma RII cell line that had been transfected with Fc gamma RIIb1. To reconcile these findings with the expression of Fc gamma RIIb1, it is postulated that immune complexes are concentrated on the cell surface by the Fc gamma RIIb1 and are thus available for preferential uptake by random fluid-phase endocytosis. This results in more efficient generation of the epitopes recognized by these T cell hybridomas.

Animals↗
PubMed1997

Analysis of the large (L) protein gene of the porcine rubulavirus LPMV: identification of possible functional domains.

The complete nucleotide sequence of the porcine rubulavirus LPMV (La Piedad Michoacan virus) large (L) protein gene was determined and analysed. The L mRNA was found to span 6,786 nucleotides, containing one single large open reading frame (ORF), putatively encoding a polypeptide of 2,251 amino acids. By aligning the amino acid sequence of the LPMV L-protein with L-protein of a number of viruses belonging to the order mononegavirale, a high degree of similarity between the LPMV L-protein and other rubula virus L-proteins was demonstrated, extending through almost the whole protein. Additionally we could identify several regions as being highly conserved among all studied viruses of the order mononegavirale. The significance of these regions are discussed.

Amino Acid Sequence↗
PubMed1997

Problems and promises of the protocol.

Creating protocols (or guidelines, standards) for medical work is becoming big business. The pros and cons of protocols have been reiterated many times: advocates argue that protocols may enhance the quality of care, reduce unwanted variations in practice, and may help to render medical practice more scientific. Critics, on the contrary, argue that protocols will lead to cookbook medicine, to de-skilling, and to a reduced quality of care. In the continuing reiteration of these claims, they have more and more become removed from the actual practices of medical work and of the creation and use of protocols. Building on empirical research of these practices, this paper attempts to revitalise the debate. Four problems of the protocol are discussed: the protocol reinforces the tendency to perceive and describe medical action as an individual, formally rational process; the protocol contributes to the widespread illusion of the single answer; the protocol contributes to the loss of importance of information and interventions which are difficult to explicate and/or to quantify; and the protocol will lead to an increasing bureaucratisation and regulation of health care practices. Judicious use of protocols has several promises, which are discussed subsequently: explicating a scheme of actions creates a forum for discussion, and delegating parts of the decision-making process to a protocol may lead to personnel acquiring new competences.

Clinical Competence↗
PubMed1997

Analysis of the fusion protein gene of the porcine rubulavirus LPMV: comparative analysis of paramyxovirus F proteins.

Complementary DNA clones representing the fusion (F) protein gene of the porcine rubulavirus LPMV were isolated and sequenced. The F gene was found to be 1,845 nucleotides long containing one long open reading frame capable of encoding a protein of 541 amino acids. The cleavage motif for F0 into F1 and F2 is His-Arg-Lys-Lys-Arg. A sequence comparison and a phylogenetic analysis was performed in order to identify possible functional domains of paramyxovirus fusion proteins and also to classify the porcine rubulavirus. The F gene of LPMV is most closely related to the human mumps virus and simian virus type 5 F genes, and is therefore classified into the rubulavirus genus. A coding region for a small hydrophobic protein was however not found between the F and hemagglutinin-neuraminidase (HN) genes as previously found in both SV5 and mumps.

Amino Acid Sequence↗
PubMed1997

Linkage and physical mapping of X-linked lissencephaly/SBH (XLIS): a gene causing neuronal migration defects in human brain.

While disorders of neuronal migration are associated with as much as 25% of recurrent childhood seizures, few of the genes required to establish neuronal position in cerebral cortex are known. Subcortical band heterotopia (SBH) and lissencephaly (LIS), two distinct neuronal migration disorders producing epilepsy and variable cognitive impairment, can be inherited alone or together in a single pedigree. Here we report a new genetic locus, XLIS, mapped by linkage analysis of five families and physical mapping of a balanced X;2 translocation in a girl with LIS. Linkage places the critical region in Xq21-q24, containing the breakpoint that maps to Xq22.3-q23 by high-resolution chromosome analysis. Markers used for somatic cell hybrid and fluorescence in situ hybridization analyses place the XLIS region within a 1 cM interval. These data suggest that SBH and X-linked lissencephaly are caused by mutation of a single gene, XLIS, that the milder SBH phenotype in females results from random X-inactivation (Lyonization), and that cloning of genes from the breakpoint region on X will yield XLIS.

Cerebral Cortex↗
PubMed1997

Quantitative determination of theophylline by an automated chemiluminescent immunoassay in serum and plasma: comparison to other methods of analysis.

A chemiluminescent immunoassay for theophylline in serum or plasma was developed for the Ciba Corning ACS: 180 automated analyzer. The assay has a limit of quantitation of 0.2 microgram/ml, with a range up to 40 micrograms/ml. The cross-reactivity to metabolites 1,3-dimethyluric acid 3-methylxanthine was 3.4% and 2.5%, respectively. Overall means of 101.0% and 97.8% were determined from dilution linearity and addition studies, respectively. When compared to a high-performance liquid chromatography (HPLC) method, a linear regression of ACS Theophylline = 0.996 (HPLC) + 0.35, r = 0.991, n = 93, was obtained. Similar results were obtained when the ACS assay was compared to other immunoassays. Precision (within-run and total coefficient of variation or CV) was < 6% in the therapeutic range (10-20 micrograms/ml). The performance data demonstrate that the ACS Theophylline assay provides an additional choice for the clinical measurement of the drug.

Chromatography, High Pressure Liquid↗
PubMed1997

Functional interactions between papillomavirus E1 and E2 proteins.

DNA replication of papillomaviruses requires the viral E1 and E2 proteins. These proteins bind cooperatively to the viral origin of replication (ori), which contains binding sites for both proteins, forming an E1-E2-ori complex which is essential for initiation of DNA replication. To map the domains in E2 that are involved in the interaction with E1, we have used chimeric bovine papillomavirus (BPV)/human papillomavirus type 11 (HPV-11) E2 proteins. The results from this study show that both the DNA binding domain and the transactivation domain from BPV E2 independently can interact with BPV E1. However, the roles of these two interactions are different: the interaction between E1 and the activation domain of E2 is necessary and sufficient for cooperativity in binding and for DNA replication; the interaction between E1 and the DNA binding domain of E2 is required only when the binding sites for E1 and E2 are adjacent to each other, and the function of this interaction appears to be to facilitate the interaction between E1 and the transactivation domain of E2. These results indicate that the cooperative binding of E1 and E2 to the BPV ori takes place via a novel two-stage mechanism where one interaction serves as a trigger for the formation of the second, productive, interaction between the two proteins.

Binding Sites↗
PubMed1997

Experiences with an electronic patient record in a clinical context: considerations for design.

This paper argues that we should see medical work practices as natural systems, and that we should understand the process of IT design as the development of sociotechnical configurations. Drawing upon our experiences with an electronic patient record (EPR) on an Intensive Care Unit, several considerations for design are developed. First, the EPR should not be overly structured with rationalistic and pre-fixed notions of the organization and content of medical work. Second, it is crucial to ensure that the usage of the system will yield immediate benefits for primary users: the systems should support work; not generate it. Third, designing IT should include being aware of the socio-political nature of seemingly 'neutral' tools as EPRs.

Documentation↗
PubMed1996

The acyl carrier protein of malonate decarboxylase of Malonomonas rubra contains 2'-(5"-phosphoribosyl)-3'-dephosphocoenzyme A as a prosthetic group.

Malonate decarboxylase of Malonomonas rubra is composed of soluble and membrane-bound components and contains an acetyl residue that is essential for catalytic activity. Upon incubation with hydroxylamine, the acetyl residue is removed, forming an inactive thiol enzyme, which is reactivated by acetylation with ATP, acetate, and a specific ligase. After incubation of the thiol enzyme with iodoacetate in the presence of excess dithioerythritol, the prosthetic group thiol residue was carboxymethylated and reactivation by acetylation was impaired. Radioactive labeling with [1-14C] iodoacetate revealed the site of carboxymethyation on a distinct cytoplasmic protein with the apparent molecular mass of 14 000 Da. The same protein was specifically labeled by enzymic acetylation of the thiol enzyme with [1-14C]acetate and ATP. Malonate decarboxlyation by [14C]acetyl malonate decarboxlyation resulted in the release of the radioactive acetyl residue from the enzyme,indicating that this acetyl residue is exchanged for a malonyl residue during catalysis. The acyl carrier protein has been purified as its [14C]carboxymethylated derivative to apparent homogeneity. The prosthetic group of the acyl carrier protein was isolated after alkaline hydrolysis, and its chemical structure was identified by high-performance liquid chromatography (HPLC) with the corresponding compound from citrate lyase from Klebsiella pneumoniae as reference and by mass spectrometry. Malonate decarboxylase was found to carry the same prosthetic group as citrate lyase, i.e. 2'-(5"-phosphoribosyl)-3'-dephospho-CoA.

Acyl Carrier Protein↗
PubMed1996

Malonate decarboxylase of Klebsiella pneumoniae catalyses the turnover of acetyl and malonyl thioester residues on a coenzyme-A-like prosthetic group.

During aerobic growth of Klebsiella pneumoniae on malonate, a soluble malonate decarboxylase is induced. Malonate decarboxylation consumes a proton (not H2O) and forms acetate and CO2 (not HCO3-) as products. The enzyme was purified 56-fold to apparent homogeneity. It has a native molecular mass of 142 kDa and consists of four subunits alpha, beta, gamma and delta with molecular masses of 65, 34, 30, and 12 kDa, respectively. Two different forms of the enzyme were recognised: a catalytically inactive SH-enzyme and the catalytically active acetyl-S-enzyme which is formed by post-translational acetylation of the SH-enzyme with ATP, acetate and a specific ligase. The acetyl-S-enzyme was converted into the SH-enzyme by incubation with hydroxylamine or dithioerythritol. Chemical reacylation of the SH-enzyme, which restores catalytic activity, was achieved with acetic anhydride or more efficiently with malonyl-CoA. This acylation of the SH group was prevented after incubation with various thiol-specific reagents. After incubation of the SH-enzyme with iodo[1-14C]acetate, the delta subunit became specifically labelled. This subunit was also labelled after incubation of the acetyl-S-enzyme with [2-14C]malonate. The radioactivity was completely liberated from the protein upon malonate addition. These results indicate that the delta subunit is the acyl-carrier protein of the complex and that malonate decarboxylation proceeds in two steps: the acetyl residue on the ACP is first replaced by a malonyl residue which subsequently undergoes decarboxylation thereby regenerating the acetyl-S-ACP. The binding site for the acyl residues on the acyl-carrier protein was shown to be 2'-(5"-phosphoribosyl)-3'-dephospho-CoA after alkaline cleavage of this prosthetic group from the enzyme and chromatographic as well as mass spectroscopic analyses.

Bicarbonates↗
PubMed1996

High sensitivity collisionally-activated decomposition tandem mass spectrometry on a novel quadrupole/orthogonal-acceleration time-of-flight mass spectrometer.

Consideration of the special problems encountered in ultra-high sensitivity biopolymer sequencing studies has led to the development of a novel quadrupole/erthogonal-acceleration time-of-flight tandem mass spectrometer described for the first time here. The performance characteristics of this new geometry are demonstrated, including fully resolved daughter-ion spectra with mass accuracies of 0.1 dalton, which allow removal of interpretation ambiguities and easy differentiation of charge states even in weak collisionally-activated decomposition tandem mass spectra. The instrument has been applied to a variety of biopolymer research problems, including the structure determination of major histocompatibility complex peptide antigens using liquid chromatography/electrospray mass spectrometry and nanoflow-electrospray tandem mass spectrometry, and sequencing capability in the low-femtomole and attomole ranges is demonstrated.

Amino Acid Sequence↗
PubMed1996

Working with protocols: a sociological view.

This sociological study discusses three assumptions on the nature of medical work, which can be found in protocols. First, protocols assume that medical data exist as clear-cut, elementary bits of information. Second, they assume that medical criteria are well-defined and pre-set, fixed rules, which merely have to be applied. Finally, protocols depict medical work as a sequence of individual steps which each need to be terminated before the following can be made. Sociological studies of physicians at work, however, show that medical work is characterised by interactive, pragmatic reasoning, by fluid criteria, and by the (re)constructive nature of medical data. By discussing the three assumptions, this article demonstrates how medical personnel have to actively intervene to prevent the protocols' misalignment with the nature of medical work from creating problems. This does not mean that protocols are 'bad tools': the fact that it takes work to get a technology to function does not disqualify it. But this observation does imply that protocols cannot be regarded as tools which simply 'support' the work of physicians. Also, these observations shed an interesting light on the prevalent claim that protocols 'rationalise' medical work.

Clinical Protocols↗
PubMed1996

Women's experience of the encounter with the midwife during childbirth.

OBJECTIVE: to describe women's experience of the encounter with the midwife during childbirth. DESIGN: a qualitative study using a phenomenological approach. Data were collected via tape-recorded interviews. SETTING: the Alternative Birth Care Centre, Sahlgrenska University Hospital, Gothenburg, Sweden in 1994. PARTICIPANTS: 18 women, six primiparous and 12 multiparous who were two to four days post delivery. KEY FINDINGS: the essential structure of the studied phenomenon was described as 'presence' and included three themes: to be seen as an individual, to have a trusting relationship and to be supported and guided on one's own terms. IMPLICATIONS FOR PRACTICE: the need to be seen as an individual can be realised by affirmation and familiarity with the midwife and surroundings. A trusting relationship can be obtained by good communication and proficient behaviour. By providing a sense of control the women can be supported and guided on their own terms. Above all they must feel that the midwife is present.

Adult↗