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M de Haan

Publications and source records attributed to M de Haan.

At least 37 records · Page 2Linked to original sources
PubMed2000

Sequence and analysis of chromosome 3 of the plant Arabidopsis thaliana.

Arabidopsis thaliana is an important model system for plant biologists. In 1996 an international collaboration (the Arabidopsis Genome Initiative) was formed to sequence the whole genome of Arabidopsis and in 1999 the sequence of the first two chromosomes was reported. The sequence of the last three chromosomes and an analysis of the whole genome are reported in this issue. Here we present the sequence of chromosome 3, organized into four sequence segments (contigs). The two largest (13.5 and 9.2 Mb) correspond to the top (long) and the bottom (short) arms of chromosome 3, and the two small contigs are located in the genetically defined centromere. This chromosome encodes 5,220 of the roughly 25,500 predicted protein-coding genes in the genome. About 20% of the predicted proteins have significant homology to proteins in eukaryotic genomes for which the complete sequence is available, pointing to important conserved cellular functions among eukaryotes.

Arabidopsis↗
PubMed2000

[Prevention of lactic acidosis due to metformin intoxication in contrast media nephropathy].

Use of the oral antidiabetic drug metformin may cause lactic acidosis, a rare but life-threatening complication, especially in patients with renal function loss. Since intravenously administered iodide-containing contrast media may cause renal function disturbances precautions should be taken in metformin-treated patients for whom a radiological study with intravenous contrast media is considered. In diabetic patients who use metformin a serum creatinine concentration should be measured prior to the radiological study. If the serum creatinine is within normal limits (< 130 mumol/l), metformin can be continued and the examination performed. If the serum creatinine concentration is increased (> or = 130 mumol/l), metformin should be discontinued and replaced by another antidiabetic drug if necessary. The radiological procedure with intravenous contrast media should be postponed for 48 hours. If such a procedure cannot be postponed, additional measures to prevent lactic acidosis (hydration, monitoring of the renal function) should be taken.

Acidosis, Lactic↗
PubMed2000

Modulation of event-related potentials by prototypical and atypical faces.

High-density event-related potentials (HD-ERPs) were recorded while adults passively viewed colour images of faces that artificially (Experiment I) or naturally (Experiment II) differed in configuration. In Experiment I, altering features of faces to make them less typical and less attractive did not affect the amplitude of N170, but did affect the amplitude of P1 and P2. In Experiment II, the P1 and N170 were larger for unattractive and atypical faces compared with attractive and typical faces, in the absence of P2 effects. The results show for the first time that variations in facial configuration modulate ERP activity as early as P1, but that modulation of later latency components depends on the nature of the stimuli and implicit task demands.

Adult↗
PubMed2000

Explicit memory in low-risk infants aged 19 months born between 27 and 42 weeks of gestation.

The aim of this study was to determine whether there are primary effects of prematurity on the development of explicit memory. Elicited imitation of action sequences was used to compare immediate and 15-minute delayed memory in term and preterm infants (19 months corrected age; n=48) who were at low risk: none had experienced the medical or social risk factors often associated with preterm birth. Relative to infants born at term (38 to 40 weeks' gestation), children who had been born at 27 to 34 weeks' gestation showed lower levels of ordered recall; performance of healthy infants born at 35 to 37 weeks' gestation was intermediate and did not differ significantly from that of the other groups. These results suggest that specific cognitive deficits can occur as a function of preterm birth even in low-risk infants.

Cognition Disorders↗
PubMed2000

Reliability of the amsterdam clinical challenge scale (ACCS): a new instrument to assess the level of difficulty of patient cases in medical education.

INTRODUCTION: In problem-based medical curricula, consideration should be given to the level of difficulty of patient cases used for training and assessment. The Amsterdam Clinical Challenge Scale (ACCS) has been developed to assess the degree of difficulty of patient cases in a systematic and reproducible manner. To determine the reliability of the instrument two research questions were addressed: (1) How many judges are required, on the basis of the total score of the ACCS, to obtain a reliable estimate of the difficulty of a single case? (2) How many cases and/or how many judges are needed to reach an acceptable level of reliability of the total score of the ACCS? METHOD: Four judges scored 36 patient scripts reflecting a wide range of patient problems encountered in general practice. Each script was scored four times. In the reliability analysis, the generalizability theory was applied. RESULTS: The results show that the judges did, indeed, use the whole range of difficulty ratings. When the ACCS is applied to a single case, eight or more judges are needed to reach an acceptable level of reliability. When more cases are involved, fewer judges are needed; for 10 or more cases one judge will be sufficient. CONCLUSIONS: Given the typical length, for example of an objective structured clinical examination, the ACCS makes it possible to provide a reliable estimate of the level of difficulty of such a test with only a limited number of judges.

Clinical Competence↗
PubMed1999

Sequence and analysis of chromosome 4 of the plant Arabidopsis thaliana.

The higher plant Arabidopsis thaliana (Arabidopsis) is an important model for identifying plant genes and determining their function. To assist biological investigations and to define chromosome structure, a coordinated effort to sequence the Arabidopsis genome was initiated in late 1996. Here we report one of the first milestones of this project, the sequence of chromosome 4. Analysis of 17.38 megabases of unique sequence, representing about 17% of the genome, reveals 3,744 protein coding genes, 81 transfer RNAs and numerous repeat elements. Heterochromatic regions surrounding the putative centromere, which has not yet been completely sequenced, are characterized by an increased frequency of a variety of repeats, new repeats, reduced recombination, lowered gene density and lowered gene expression. Roughly 60% of the predicted protein-coding genes have been functionally characterized on the basis of their homology to known genes. Many genes encode predicted proteins that are homologous to human and Caenorhabditis elegans proteins.

Animals↗
PubMed1999

Brain activity differentiates face and object processing in 6-month-old infants.

Event-related potentials were used to determine whether infants, like adults, show differences in spatial and temporal characteristics of brain activation during face and object recognition. Three aspects of visual processing were identified: (a) differentiation of face vs. object (P400 at occipital electrode was shorter latency for faces), (b) recognition of familiar identity (Nc, or negative component, at fronto-temporal electrodes [FTEs] was of larger amplitude for familiar stimuli), and (c) encoding novelty (slow wave at FTEs was larger for unfamiliar stimuli). The topography of the Nc was influenced by category type: Effects of familiarity were limited to the midline and right anterior temporal electrodes for faces but extended to all temporal electrodes for objects. Results show that infants' experience with specific examples within categories and their general category knowledge influence the neural correlates of visual processing.

Adult↗
PubMed1999

Bockenheimer's syndrome.

A case of a very extensive form of the rare Bockenheimer's syndrome (genuine diffuse phlebectasia) in a 45-year-old female patient is presented. The subject presented phlebectasias of the upper right leg, the vulva and the right side of the abdomen. The diagnostic and therapeutic possibilities for cases of patients with Bockenheimer's syndrome are described.

Abdominal Muscles↗
PubMed1998

Familiar and novel contexts yield different associations between cortisol and behavior among 2-year-old children.

We examined 10:30 a.m. salivary cortisol levels in twenty-four 2-year-old children at home, and then at several points during transition into preschool: Week 1, Weeks 6-9, and the 1st week following a month-long holiday break. Cortisol levels did not increase when the children first started school as compared to either home or later school levels. Cortisol levels were correlated across similar, but not across dissimilar, psychosocial contexts. Home levels were correlated wit more shy, anxious, internalizing behavior while the response to starting school was correlated with more assertive, angry, and aggressive behavior. Behavior was assessed using parent temperament reports, teacher reports, and observational measures. We conclude that HPA activity as indexed by salivary cortisol measures is differentially associated with behavior in familiar and novel contexts. Consistent with our prior work, shy/anxious behavior is not significantly associated with elevations in cortisol when young children enter new social situations.

Child Behavior Disorders↗
PubMed1998

Delayed recognition memory in infants and adults as revealed by event-related potentials.

The present study sought to compare adult and infant ERP responses in analogous tests of visual recognition memory. Adults were tested under two test conditions, in which they were given either explicit instructions to respond to a previously-seen stimulus, or no instructions. Testing in both conditions took place after either a 1- or 5-min delay between familiarization and test. Eight-month-old infants were tested under the same 'passive' (no instruction) conditions as adults. ERP morphology differed across age groups. Adults evinced a P300 that was larger under 'active' as compared to 'passive' test conditions, and a late positive slow wave response that was greater to novel than familiar stimuli. There was no evidence in infants of a P300, although infants did demonstrate a late positive slow wave that was greater to familiar than to novel stimuli. Parallels between the infant and adult findings are discussed and in particular, whether the infant slow wave response is the precursor to the adult P300.

Adolescent↗
PubMed1998

Care for the chronically ill: the future role of health care professionals and their patients.

In future decades the number of chronically ill will increase drastically. A function-orientated approach, substitution and transmural care would seem to be the key objectives for the necessary improvement in care. There will be significant changes in the task division of care provided by specialists, general practitioners and paramedics. At the same time, patients will be able to increase their own potential for self-care. Who will play which role in future will have to be considered against the background of the various phases in the course of a chronic disease. In the initial stages, in particular, there will be ample opportunity to involve patients more in their own care. This will have a positive influence on learning to live with a chronic disease, dependence on medical help and the course of the disease itself. Transdisciplinary collaboration, that means interactive collaboration with the necessary mutual knowledge and understanding of the working methods, should form the basis of the care in all phases of a chronic disease. Different carers are involved in each phase of care for the chronically ill, but since the general practitioner is involved in all phases, it is obvious that the necessary organization of collaboration between the various carers (including the patient) should be coordinated by the general practitioner.

Chronic Disease↗
PubMed1998

Long-term recognition memory for faces assessed by visual paired comparison in 3- and 6-month-old infants.

It has been argued that operant conditioning is the only type of long-term memory present in infants prior to 6 months of age. In this study, memory for faces was investigated in 3- and 6-month-old infants with a visual paired-comparison task. In Experiment 1, infants were habituated to a face presented in different poses; recognition was assessed after a 2-min or a 24-hr retention interval. The 6-month-old infants and the male but not the female 3-month-old infants exhibited novelty preferences. A 2nd experiment showed that 3-month-old female infants were delayed relative to male infants in their face-processing ability rather than in their memory capacity. The results of Experiment 3 demonstrated in 3-month-olds an electrophysiological correlate of delayed recognition memory. These findings are discussed in the context of the neural systems thought to be involved in visual recognition memory (but not in procedural memory), namely the limbic system.

Child Development↗
PubMed1998

Does the care given by general practitioners and midwives to patients with (imminent) miscarriage meet the wishes and expectations of the patients?

OBJECTIVE: In 1989 a Dutch national guideline on (imminent) miscarriage was developed for use in general practice. A prospective recording study was carried out to determine how the patients evaluated the care they received from general practitioners (GPs) and midwives who agreed to adhere to this (imminent) miscarriage guideline and to determine the aspects that influence this evaluation. SETTING: GP practices and midwifery practices in The Netherlands. DESIGN: Prospective recording of appointments during 4 consecutive weeks in a diary by patients who contacted their GP or midwife with symptoms of (imminent) miscarriage. STUDY PARTICIPANTS: Over a period of 12 months, 75 GPs and 43 midwives recorded all patients (n = 407) showing symptoms of (imminent) miscarriage. In total 265 patients had completed at least the first contact in the diary; 200 patients actually recorded all contacts. RESULTS: Most patients gave their GP or midwife a high evaluation score (8.2 or 8.7 respectively). Yet, 20% thought that the care could be improved if the GP or midwife gave more information, was more empathetic and carried out an ultrasound scan. In determining the aspects that have most influence on the patients' evaluation, empathy and support came first, followed by involvement of the patient in decision making, putting her at ease, and the total duration of the contacts. Although patients who wanted a referral gave a lower score, this seems to be of less importance than the above mentioned aspects. Expecting and getting an ultrasound scan did not influence the patient's evaluation.

Abortion, Threatened↗
PubMed1998

Social behavior correlates of cortisol activity in child care: gender differences and time-of-day effects.

The relations between social behavior and daily patterns of a stress-sensitive hormone production were examined in preschool children (N = 75) attending center-based child care. Three behavioral dimensions, shy/anxious/internalizing, angry/aggressive/externalizing, and social competence, were assessed by teacher report and classroom observation, and their relations with 2 measures of cortisol activity, median (or typical) levels and reactivity (quartile range score between second and third quartile values) were explored. Cortisol-behavior relations differed by gender: significant associations were found for boys but not for girls. Specifically, for boys externalizing behavior was positively associated with cortisol reactivity, while internalizing behavior was negatively associated with median cortisol. Time of day of cortisol measurement affected the results. Surprisingly, median cortisol levels rose from morning to afternoon, a pattern opposite to that of the typical circadian rhythm of cortisol. This rise in cortisol over the day was positively correlated with internalizing behavior for boys. The methodological and theoretical implications of these findings for the study of the development of hormone-behavior relations are discussed.

Child Behavior↗
PubMed1997

The nucleotide sequence of Saccharomyces cerevisiae chromosome XV.

Chromosome XV was one of the last two chromosomes of Saccharomyces cerevisiae to be discovered. It is the third-largest yeast chromosome after chromosomes XII and IV, and is very similar in size to chromosome VII. It alone represents 9% of the yeast genome (8% if ribosomal DNA is included). When systematic sequencing of chromosome XV was started, 93 genes or markers were identified, and most of them were mapped. However, very little else was known about chromosome XV which, in contrast to shorter chromosomes, had not been the object of comprehensive genetic or molecular analysis. It was therefore decided to start sequencing chromosome XV only in the third phase of the European Yeast Genome Sequencing Programme, after experience was gained on chromosomes III, XI and II. The sequence of chromosome XV has been determined from a set of partly overlapping cosmid clones derived from a unique yeast strain, and physically mapped at 3.3-kilobase resolution before sequencing. As well as numerous new open reading frames (ORFs) and genes encoding tRNA or small RNA molecules, the sequence of 1,091,283 base pairs confirms the high proportion of orphan genes and reveals a number of ancestral and successive duplications with other yeast chromosomes.

Base Sequence↗
PubMed1997

Temperament, social competence, and adrenocortical activity in preschoolers.

The relations among temperament, social competence, and levels of a stress-sensitive hormone (salivary cortisol) were examined in two studies of preschoolers children (Study 1, N = 29; Study 2, N = 46). In both studies, we sampled cortisol daily for the initial weeks of school year (Group Formation period) and for several weeks later in the year (Familiar Group period). For each child, we examined two measures of cortisol activity (separately for each period) based on the distribution of cortisol levels across days: (a) median cortisol (50th percentile) and (b) cortisol reactivity (the difference between the 75th and 50th percentile). Median cortisol was modestly stable across periods, but cortisol reactivity was not. Children who showed high cortisol reactivity (75th minus 50th percentile > or = 0.10 micrograms/dl) during the Group Formation period but low-to-normal cortisol reactivity during the Familiar Group period were outgoing, competent, and well liked by their peers. In contrast, children who changed from low/normal to high cortisol reactivity and those who maintained high cortisol reactivity from the Group Formation to Familiar Group period were affectively negative and solitary. Children who showed high median cortisol during the Familiar Group period or over both periods scored lower on a measure of attentional and inhibitory control. Together, these results suggest that relations among temperament, social competence, and neuroendocrine reactivity reflect both individual and contextual differences.

Affect↗
PubMed1997

Adherence by midwives to the Dutch national guidelines on threatened miscarriage in general practice: a prospective study.

OBJECTIVE: To determine the feasibility for midwives to adhere to Dutch national guidelines on threatened miscarriage in general practice. DESIGN: Prospective recording of appointments by midwives who agreed to adhere to the guidelines on threatened miscarriage. Interviews with the midwives after they had recorded appointments for one year. SETTING: Midwifery practices in The Netherlands. SUBJECTS: 56 midwives who agreed to adhere to the guidelines; 43 midwives actually made records from 156 clients during a period of 12 months. MAIN OUTCOME MEASURES: Adherence to each recommendation and reasons for non-adherence. RESULTS: The recommendation that a physical examination should take place on the first and also on the follow up appointment was not always adhered to. Reasons for non-adherence were the midwives' criticism of this recommendation, their lack of knowledge or skills, and the specific client situation. Adherence to a follow up appointment after 10 days, a counselling consultation after six weeks, and not performing an ultrasound scan was low. Reasons for non-adherence were mainly based on the midwives' criticism of these recommendations and reluctance on the part of the client. Furthermore, many midwives did not give information and instructions to the client. It is noteworthy that in 13% of the cases the midwife's policy was overridden by the obstetrician taking control of the situation after the midwife had requested an ultrasound scan. CONCLUSIONS: Those recommendations in the guidelines on threatened miscarriage that are most often not adhered to should be reviewed. To reduce conflicts about ultrasound scans and referrals, agreement on the policy on threatened miscarriage should be mutually established between midwives and obstetricians.

Abortion, Threatened↗