PubMed Health⌕ Search

Biomedical subjects

K V Andersen

Publications and source records attributed to K V Andersen.

At least 37 records · Page 2Linked to original sources
PubMed1996

Structure in solution of a four-helix lipid binding protein.

Because of the low solubility of lipids in water, intercellular and intracellular pathways of lipid transfer are necessary, e.g., for membrane formation. The mechanism by which lipids in vivo are transported from their site of biogenesis (endoplasmatic reticulum and the chloroplasts) to their place of action is unknown. Several small plant proteins with the ability to mediate transfer of radiolabeled phospholipids in vitro from liposomal donor membranes to mitochondrial and chloroplast acceptor membranes have been isolated, and a protein with this ability, the nonspecific lipid transfer protein (nsLTP) isolated from barley seeds (bLTP), has been studied here. The structure and the protein lipid interactions of lipid transfer proteins are relevant for the understanding of their function, and here we present the three-dimensional structure in solution of bLTP as determined by NMR spectroscopy. The 1H NMR spectrum of the 91-residue protein was assigned for more than 97% of the protein 1H atoms, and the structure was calculated on the basis of 813 distance restraints from 1H-1H nuclear Overhauser effects, four disulfide bond restraints, from dihedral angle restraints for 66 phi-angles, 61 chi 1 angles, and 2 chi 2 angles, and from 31 sets of hydrogen bond restraints. The solution structure of bLTP consists of four well-defined alpha-helices A-D (A, Cys 3-Gly 19; B, Gly 25-Ala 38; C, Arg 44-Gly 57; D, Leu 63-Cys 73), separated by three short loops that are less well defined and concluded by a well defined C-terminal peptide segment with no observable regular secondary structure. For the 17 structures that are used to represent the solution structure of bLTP, the RMS deviation to an average structure is 0.63 A +/- 0.04 A for backbone atoms and 0.93 A +/- 0.06 A for all heavy atoms. The secondary structure elements and their locations in the sequence resemble those of nsLTP from two other plant species, wheat and maize, whose structures were previously determined (Gincel E et al, 1995, Eur J Biochem 226:413-422; Shin DH et al, 1995, Structure 3:189-199). In bLTP, the residues analogous to those in maize nsLTP that constitute the palmitate binding site are forming a similar hydrophobic cavity and a potential acyl group binding site. Analysis of the solution structure of bLTP and bLTP in complex with a ligand might provide information on the conformational changes in the protein upon ligand binding and subsequently provide information on the mode of ligand uptake and release. In this work, we hope to establish a foundation for further work of determining the solution structure of bLTP in complex with palmitoyl coenzyme A, which is a suitable ligand, and subsequently to outline the mode of ligand binding.

Amino Acid Sequence↗
PubMed1995

Physical examinations and laboratory tests in antenatal care visits in Denmark. Do reported practice and current official guidelines concord with results of literature reviews? A nationwide study of the public scheme of shared antenatal care in general practice, centres of midwifery and hospital outpatients' clinics.

OBJECTIVE: To analyse physical examinations and laboratory tests reported in antenatal care visits in relation to official guidelines and reviews of appropriateness. DESIGN: A nationwide cross sectional study based on questionnaires completed by general practitioners (GPs), midwives, and hospital doctors. Physical examinations and laboratory tests in connection with one specific visit were reported. SUBJECTS: The questionnaires were completed by 722 GPs (61% of eligible from a random sample), 584 midwives (86% of eligible), 250 hospital doctors who made health examinations in pregnancy, week 16-18 (63% of eligible), and 181 hospital doctors who saw women with at-risk pregnancies (55% of eligible). RESULTS: General practice: weight, blood pressure (BP) measurement, and test for proteinuria were reported in more than 90% of visits. Urine culture was reported in 46%, and cervical smear in 41% of first visits. Rubella antibody test at the first visit was only reported in 23% of nulliparae. Vaginal examination was reported in 95% of first visits. Fewer were reported in second (27%) and third (48%) routine visits during pregnancy. Midwives: checks of BP, oedema, and proteinuria were reported in more than 95% of visits irrespective of week of gestation. Vaginal examination was reported in about a third of checkups. Hospitals: vaginal examination was reported in 66% of checkups in at-risk pregnancies. CONCLUSIONS: A surplus of resources were spent on (repeat) examinations and tests with little or no documented benefit. Cervical cytology was grossly overused. Urine culture and rubella serology were not sufficiently applied.

Clinical Laboratory Techniques↗
PubMed1994

Comparison of backbone dynamics of apo- and holo-acyl-coenzyme A binding protein using 15N relaxation measurements.

15N magnetic relaxation parameters T1, T2 and the nuclear Overhauser effect in the protein acyl-coenzyme A binding protein (ACBP) have been measured in the presence and absence of the ligand, palmitoyl-coenzyme A, in order to obtain information about local and global dynamical properties of the peptide backbone with and without the ligand bound in the binding site. The three-dimensional structures of acyl-coenzyme A binding protein are known for both states of the protein as determined from multidimensional heteronuclear NMR studies, and they have been shown to be essentially identical. However, the dynamics of the backbone is influenced by the presence of ligand in the binding site. The binding of ligand had significant and specific effects on the relaxation time T1 for many of the 15N in the peptide backbone, in particular those near residues with contacts to the ligand. Similarly, the nuclear Overhauser effect at 15N near such residues increased. There were no significant changes in the T2 relaxation. T1 values showing a significant decrease and NOEs increasing in regions close to the binding site when the ligand was bound suggest two modes of action on the dynamics of the protein when the ligand is binding. The reduced T1 indicates motion of lower amplitude in agreement with the structural constraints introduced by protein-ligand interactions. The increased NOEs may be a consequence of shorter time constants for dynamics of the atoms close to the binding site. The Lipari-Szabo model could not be satisfactorily applied to the entire set of experimental data.(ABSTRACT TRUNCATED AT 250 WORDS)

Carrier Proteins↗
PubMed1994

[Preventive check-ups of pregnant women in Denmark. Common ailments in pregnancy].

The study was conducted in order to describe the extent and content of advice on common ailments in pregnancy given by doctor or midwife during prenatal visits and to describe the frequency of ailments in the period before the visits. The design was a nationwide cross-sectional study based on questionnaires completed by pregnant women who had seen a general practitioner (GP), midwife or hospital doctor for prenatal care. Ailments and advice in connection with one specific visit were reported. The questionnaires were completed by 517 women after a prenatal visit to their GP (92% of eligible), by 514 women after a prenatal visit to the midwife (91% of eligible), and by 203 women after a prenatal visit to a doctor in the maternity department in pregnancy week 16-18 (84% of eligible). The results showed that nausea, pollakisuria, tiredness and heartburn had been present during the period before the visit in about half the women. Between a third and a fourth of the women had been discomforted by back pain, discharge or cramps. From 15 to 58 percent had been given advice, depending on the symptom. The advice was of many different kinds. To a large extent the women wanted to talk to the health professionals about the ailments, and most often they wanted to talk to a midwife about the ailments. We conclude that common ailments of pregnancy are frequent and they should be investigated more. Nearly all pregnant women want to talk about the subject during prenatal visits. The objectives of giving advice should be clearer, and clinical studies of the effectiveness of the advice are needed.

Cross-Sectional Studies↗
PubMed1993

[Risk of development of epileptic seizures in children with subclinical "epileptogenic" EEG abnormalities].

Sixty-six non-epileptic children with focal spikes in EEG and without cerebral palsy were followed for 16 to 35 years. The cumulative risk of developing one or more seizures was 33% when the first abnormal EEG was recorded, and increased to about 80% if abnormalities persisted three or more years. Focal spike activity was most persistent in children with retarded development or with organic brain diseases. We conclude that the presence of focal EEG spikes in children without epileptic seizures can be considered epileptogenic, especially if the abnormality is persistent and associated with clinical evidence of organic brain disorder.

Adolescent↗
PubMed1993

Three-dimensional structure of the complex between acyl-coenzyme A binding protein and palmitoyl-coenzyme A.

Multidimensional 1H, 13C and 15N nuclear magnetic resonance spectroscopy has been used to study the complex between palmitoyl-coenzyme A and acyl-coenzyme A binding protein. The 1H and the 15N spectra of the holo-protein have been almost completely assigned and so has most of the 1H spectrum of the coenzyme A part of the protein-bound ligand. The palmitoyl part of the ligand has been uniformly labelled with 13C and the nuclear magnetic resonance signals of the carbon atoms and their protons have been assigned at the two ends of the hydrocarbon chain. A total of 1251 distance restraints from nuclear Overhauser effects and 131 dihedral angle restraints from three-bond coupling constants provided the basis for the structure calculation. A comparison of 20 structures calculated from these data to the average structure showed that they could be aligned with an atomic root-mean-square deviation of 1.3(+/- 0.2) A for all C, N, O, P and S atoms in protein and ligand. The apo-protein is a four-helix protein and this structure is maintained in the holo-protein. The four alpha-helices are Ac1 of residues 3 to 15, Ac2 from residue 20 to 36, Ac3 from 51 to 62, and Ac4 from 65 to 84. For the four alpha-helices of the peptide backbone of the holo-protein the root-mean-square deviation for the C, C alpha and N atoms was 0.42(+/- 0.08) A. The binding site for the palmitoyl-chain stretches between the N-terminal end of Ac3 where the carboxyl part binds, to the N-terminal of Ac3 where the omega-end of the palmitoyl part binds. The adenosine-3'-phosphate is bound near residues of each of the four helices in an arrangement where it can form salt bridges and/or hydrogen bonds to either backbone or side-chain atoms of Ala9, Tyr28, Lys32, Lys54 and Tyr73. The polar parts of the pantetheine and the pyrophosphate are structured in the bound ligand to form an interface with the solvent. Also the ligand forms a set of non-polar intramolecular interactions where the adenine, the pantetheine, and the palmitoyl-chain are associated, so overall the structure of the bound ligand seems to be organized to protect the lipophilic palmitoyl part from the polar solvent.

Amino Acid Sequence↗
PubMed1993

Determination of the rate constants k1 and k2 of the Linderström-Lang model for protein amide hydrogen exchange. A study of the individual amides in hen egg-white lysozyme.

The pH dependence of the amide/solvent hydrogen exchange of individual amide groups in hen egg-white lysozyme has been studied by nuclear magnetic resonance spectroscopy. Lysozyme has been used here as a model for a globular protein to re-examine the hypothesis for the amide/solvent hydrogen exchange reaction proposed by K. Linderstrøm-Lang and described in detail by Hvidt and Nielsen. The work has been focused on the most slowly exchanging amide at the temperature of 21 degrees C and in the pH range between 4 and 8. Exchange rates have been measured for 64 of the 126 amide protons and the pH dependence has been determined for 52 of these. The amides examined represent a sample that includes all the types of secondary structure and they are placed in the globular structure in a range of 3.2 A to 8.5 A from the closest water molecule on the surface. The measured exchange rates at pH 6 have been compared to these structural parameters and the results suggest that the rate constants are determined partly by the distance to the surface and partly by the type of secondary structure the amide is engaged in. Near the surface and in the very interior the distance to the surface seems to be rate-determining. Between the extremes the type of secondary structure is rate determining. The pH dependent exchange of the examined amides was shown to be in agreement with the Linderstrøm-Lang model. For each of the amides examined the rate constants for the opening and the closing reaction in the first reaction step of the Linderstrøm-Lang model has been calculated and compared to structural parameters.

Amides↗
PubMed1993

[Preventive health examinations of pregnant women in Denmark. Anamnestic practice and discussion of prenatal diagnosis in early pregnancy examinations in general practice, birth clinics and birthing centers].

In Denmark, pregnant women are offered antenatal care in a nationwide programme. This programme is organized around health examinations in general practice, hospital outpatient departments and at midwives' centres. During winter 1986-1987, a nationwide investigation of antenatal care was carried out. A random sample of approximately 1/3 of the general practitioners, all of the midwives who had antenatal consultations and the medical staffs of 26 departments of obstetrics and gynaecology received a questionnaire about content of a definite antenatal examination. 62% of the general practitioners, 63% of the doctors at the place of delivery and 86% of the midwives replied. Among the pregnant women, 92% replied from general practice, 84% from hospital outpatient departments and 91% from midwives' centres. The interviews about date of delivery and genetic counselling at early visits in general practice, hospital outpatient departments and at midwives' centres were in agreement with the nationwide guidelines. Employment of routine ultrasound scanning was not associated with less detailed history taking by the doctors at hospital outpatient departments, where ultrasound scanning was employed only on special indications. It was concluded that there was a considerable overlap between the interview about the date of delivery and genetic counselling at early visits in general practice and in hospital outpatient departments and, to some extent, at the midwives' centres. The sharing of responsibility for care of pregnant women by three professional groups requires specification of the content of the consultation. Official guidelines should be more specific about this point.

Birthing Centers↗
PubMed1993

The three-dimensional structure of acyl-coenzyme A binding protein from bovine liver: structural refinement using heteronuclear multidimensional NMR spectroscopy.

The 3D structure of bovine recombinant acyl-coenzyme A binding protein has been determined using multidimensional heteronuclear magnetic resonance spectroscopy in a study that combines investigations of 15N-labeled and unlabeled protein. The present structure determination is a refinement of the structure previously determined (Andersen, K.V. and Poulsen, F.M. (1992) J. Mol. Biol., 226, 1131-1141). It is based on 1096 distance restraints and 124 dihedral angle restraints of which 69 are for phi-angles and 8 for chiral centers and 47 for prochiral centers. The new experimental input for the structure determination has provided an increase of 263 distance restraints, 5 phi-angle restraints, and 32 chi-angle restraints in 2 chiral centers, and 31 prochiral centers restraining an additional 23 chi 1, 8 chi 2, and 1 chi 3 angles. The increase of 300 distance and dihedral angle restraints representing an additional 30% of input parameters for the structure determination has been shown to be in agreement with the first structure. A set of 29 structures has been calculated and each of the structures has been compared to a mean structure to give an atomic root mean square deviation of 0.44 +/- 0.12 A (1 A is 0.1 nm) for the backbone atoms C, C alpha, and N in the four alpha-helices A1, residues 4-15, A2, residues 21-36, A3, residues 51-62 and A4, residues 65-84. The loop-region of residues Gly45-Lys50 could not be defined by the restraints obtained by NMR. The program PRONTO has been used for the spectrum analysis, assignment of the individual nuclear Overhauser effects, the integration of the cross peaks, and the measurement of the coupling constants. The programs DIANA, X-PLOR and INSIGHT have been used in the structure calculations and evaluations.

Amino Acid Sequence↗
PubMed1993

Reliability in perinatal audit. A qualitative study--a preliminary investigation.

The aim of this study was to elucidate some aspects of reliability in perinatal audit, both by describing aspects of the ways in which consensus is reached between experts in perinatal audit and by examining the extent of agreement between two separate panels assessing peri- and neonatal care in 17 cases of neonatal deaths. The consensus process was elucidated by a questionnaire answered by 16 perinatal experts who had participated in a perinatal audit and by analyses of audiotapes. In 70-95% of the cases, most of the experts had reached the same conclusions during their work at home as the panel did after the joint discussions. The audiotapes revealed that the experts adjust their individual interpretations during discussions with other experts. Agreement in evaluation between two panels was elucidated by agreement in evaluation of the quality of antenatal care, intrapartum care, and neonatal care in the 17 cases of neonatal deaths. The two panels agreed in evaluation of antenatal care in 15 cases, in intrapartum care in 14 cases, and in neonatal care in 15 cases. Although the material is small, our results seem to indicate that the conclusions drawn in perinatal audit are reliable when the experts have detailed knowledge of the structure of perinatal and neonatal care, when there are agreed standards of satisfactory care, and when they have the possibility of adjusting their individual interpretations during discussion with other experts.

Humans↗
PubMed1992

Three-dimensional structure in solution of acyl-coenzyme A binding protein from bovine liver.

The three-dimensional structure of acyl-coenzyme A binding protein as encoded by the recombinant gene in Escherichia coli has been determined using nuclear magnetic resonance (n.m.r.) spectroscopy. The structure consists of four alpha-helices A1 (residues 3 to 15), A2 (residues 20 to 36), A3 (residues 51 to 60), and A4 (residues 65 to 85). A1 and A4, and A2 and A3, run in parallel pairs. A2 runs anti-parallel to A1 and A4. The three-dimensional structure of the protein is reminiscent of a shallow bowl with a rim. The "rim" is characterized by many polar and charged groups, whereas the inside and outside surface is predominantly hydrophobic with patches of uncharged polar hydroxyl groups of threonyl, serinyl and tyrosyl residues. The inside bottom contains through two epsilon-amino groups of lysine residues (Lys13 and Lys32) suggesting that the binding site for the nucleotide part of the acyl-coenzyme A part of the ligand molecule is at the inside surface of the bowl. The structure determination was done on the basis of measurements of the intensities of nuclear Overhauser effects (NOEs) and coupling constants that were translated into interatom distance restraints for 833 atom pairs, and 87 dihedral angle restraints, of which 23 were in chiral centers. In all, 42 hydrogen bonds were identified by n.m.r. and provided an additional 84 distance restraints. A total of 20 structures were calculated and the structures can be aligned to a root-mean-square deviation of 0.5 A for the backbone atoms of the residues in the four helices. A region of six residues could not be defined by the restraints obtained by n.m.r. The program Pronto was used for the spectrum analysis in general, and especially for the assignment of the individual NOEs, the integration of the cross peaks, and the measurements of the coupling constants. The programs DIANA and X-PLOR have been used in the structure calculations and evaluations.

Animals↗
PubMed1992

Perinatal audit. Are experts biased by knowledge of outcome? A controlled study.

Perinatal audit is a method widely used for quality assurance in medicine. In clinical medicine, experiments have revealed that physicians' prior knowledge and expectations may bias their assessments. This study examined whether experts in perinatal audit were biased in their evaluation of perinatal and neonatal care when they had knowledge of the outcome. A panel of experts evaluated the quality of care in 48 infants who died in the neonatal period and 48 paired infants who survived it. The 48 pairs were randomly allocated to two groups. In the first group, the outcome of neonatal death or neonatal survival appeared in the case histories, whereas in the second group the outcome was blind. There were no differences in the assessment of quality of antenatal, delivery, and neonatal care comparing the result of the evaluation between the cases with knowledge of the outcome and the cases without knowledge of outcome. Our results indicate that the experts were not biased by the knowledge of outcome when they assessed the quality of peri- and neonatal care.

Bias↗
PubMed1991

The secondary structure in solution of acyl-coenzyme A binding protein from bovine liver using 1H nuclear magnetic resonance spectroscopy.

Acyl-coenzyme A binding protein from bovine liver and the protein expressed in Escherichia coli by the recombinant gene of this protein have been studied by two-dimensional 1H nuclear magnetic resonance spectroscopy. This protein has, in addition to the ability to bind acyl-coenzyme A, been reported to have several important physiological and biochemical functions. It is known as the diazepam binding inhibitor, as a putative neurotransmitter, as a regulator of insulin release from pancreatic cells, and as a mediator in corticotropin-dependent adrenal steroidogenesis. The only difference between the protein produced by recombinant techniques and the native acyl-coenzyme A binding protein is the N-terminal acetyl group present only in the native protein. The two proteins have 86 amino acid residues and a molecular mass of approximately 10,000 Da. Complete assignment of the 1H nuclear magnetic resonances has been obtained for a major proportion of the amino acid residues (55 residues), and partial assignment has been achieved for the others (31 residues). Sequential nuclear Overhauser effects have demonstrated that the protein has a secondary structure consisting of four alpha-helices of residues 1-15, 22-35, 52-60, and 68-85. Furthermore, a large number of long-range nuclear Overhauser effects have been identified, indicating that the assignment given here will provide a basis for a structure determination of this protein in solution by nuclear magnetic resonance spectroscopy.

Amino Acids↗
PubMed1991

[The validity of the perinatal classification by the Health Department].

On the basis of 273 perinatal and neonatal deaths in three Danish counties in 1985 and 1986, the validity of the abbreviated classification of perinatal deaths by the National Board of Health which comprises six categories was assessed. The classification is relatively robust regarding incorrect classification of International Classification of Diseases (ICD) as 87% of the deaths were classified in the relevant categories. This may be because the classification is relatively rough but also because the classification, as regards ICD diagnoses, is based on information from the register of births.

Cause of Death↗
PubMed1991

[The quality of registration of causes of death in perinatal and neonatal deaths].

The quality of registration of the causes of death in 273 perinatal and neonatal deaths was assessed. The present authors classified the causes of death according to WHO classification of disease. The authors classification was compared with the Danish Health Department's original classification of deaths and a classification undertaken by one of the staff of the Danish Health Department, the coding of which was based exclusively on information from the original death certificates (death certificate classification). Agreement between the respective forms of classification was assessed by the observed agreement for positive diagnosis and the kappa coefficients calculated by the three-figure level in the ICD diagnosis for categories and between categories of causes of perinatal and neonatal death, respectively. The investigation revealed that the deaths were classified with great accuracy by coding by the staff member when the death certificates were correctly completed. Comparison between the "authors classification" and the "Danish Health Department's original classification" and the "death certificate classification", respectively revealed that the observed agreement for positive diagnoses were 52% and 50% and that the kappa coefficients were between 0.80-0.07 and 0.81-0.04, respectively, on comparison with the three-figure levels in the ICD diagnoses and 0.93-0.32 and 0.85 and 0.32 on comparing the categories in between. It is concluded that considerable improvement in registration of perinatal and neonatal deaths may be obtained if the Danish Health Departments states precisely what information is required on the death certificate in connection with perinatal and neonatal deaths. Correspondingly, local efforts should be made to complete death certificates more correctly.

Cause of Death↗
PubMed1991

[Classification of perinatal and neonatal deaths. Fetal, obstetrical and neonatal causes].

A new method of classification of causes of death which may be employed in connection with perinatal and neonatal deaths is presented. The classification of causes of death proposed by the authors identifies the factor which probably initiated the train of events leading to death. This classification includes nine main categories and illustrates foetal conditions, happenings in pregnancy, the course of delivery and also the neonatal period. Employment of classification is proposed in regional registration of perinatal and neonatal deaths and as an aid in the current assessment of the quality of antenatal, obstetric and neonatal care as these are employed in medical audits of the perinatal and neonatal deaths in many Danish counties.

Cause of Death↗
PubMed1991

[Quality assurance in antenatal, perinatal and neonatal care. A medical audit].

Formalized quality assessment of prophylaxis, diagnosis, treatment, and care has recently been introduced in the Danish health service. A review is presented of quality assessment undertaken by the medical audit method and a model is described for quality assurance of prophylaxis, diagnosis, treatment and care during the ante-, peri and neonatal periods. The information is based partly on results from a medical audit project and also experience from work in a perinatal committee in the County of Copenhagen. The method of medical audit is reviewed, including here the specialists participating, the extent of the work and the material forming the basis for assessment of the quality. In addition, examples are quoted of criteria for satisfactory prophylaxis, diagnosis, treatment and care in the perinatal period and for how assessment by the specialists is carried out. A new classification of causes of death and review of the results of assessments of quality is presented. Finally, quality assessment as seen from the patients' point of view is discussed.

Denmark↗