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Biomedical subjects

S Hansen

Publications and source records attributed to S Hansen.

At least 19 recordsLinked to original sources
PubMed2006

Oscillometric blood pressure measurement used for calibration of the arterial tonometry method contributes significantly to error.

BACKGROUND AND OBJECTIVE: We have investigated the accuracy of the Colin tonometry module, a non-invasive alternative to intra-arterial blood pressure (BP) measurement. The claims of previous publications range between good agreement to significant discrepancies between the Colin tonometry and intra-arterial methods. The Colin method relies on calibration of the tonometry module using an oscillometric method. Our aim was to look at the effect of this calibration on the accuracy. METHODS: Ten conscious patients who already had an indwelling arterial catheter were studied. The Colin monitor was set to perform ten calibration cycles first with the oscillometric cuff on the same arm as the tonometry module and secondly on the opposite arm. Simultaneous recording of BP wave forms from the intra-arterial BP transducer and the Colin monitor allowed comparison of beat-by-beat systolic, diastolic and mean BP. RESULTS: There was considerable inter- and intra-patient variation. In the worst case, the error range was 41 mmHg over ten calibrations. Analysis of variance showed that contra- and ipsilateral calibrations gave a significantly different bias while the multiple calibrations accounted for a significant proportion of the variability in systolic BP error. CONCLUSIONS: The Colin Tonometry method is not accurate enough to be used with confidence in clinical practice. The main reason for this is its reliance on an oscillometric method for calibration of the tonometry module. Single BP measurements, using either manual or semiautomatic instruments may vary considerably from the 'true' BP due to short-term perturbations of BP.

Blood Pressure↗
PubMed2006

Links between temperamental dimensions and brain monoamines in the rat.

In 27 female Wistar rats, the authors obtained composite scores on harm avoidance and novelty seeking, as well as 57 measures of monoamines and metabolites from 10 different brain regions. A multivariate regression method was used to discover associations between individual differences in temperament and neurochemistry. Harm-avoidant subjects had low levels of striatal dopamine and high levels of cortical norepinephrine and amygdaloid 5-hydroxyindoleacetic acid. High novelty-seeking scores were linked to low levels of brainstem serotonin and dopamine and to low levels of 5-hydroxyindoleacetic acid in amygdala and accumbens. Moreover, rats scoring high on novelty seeking had higher-than-average levels of norepinephrine in the thalamus and amygdala and of serotonin in the amygdala.

Amygdala↗
PubMed2006

Facial emotion recognition in myotonic dystrophy type 1 correlates with CTG repeat expansion.

OBJECTIVE: To investigate the ability of patients with myotonic dystrophy type 1 to recognise basic facial emotions. We also explored the relationship between facial emotion recognition, neuropsychological data, personality, and CTG repeat expansion data in the DM-1 group. METHODS: In total, 50 patients with DM-1 (28 women and 22 men) participated, with 41 healthy controls. Recognition of facial emotional expressions was assessed using photographs of basic emotions. A set of tests measured cognition and personality dimensions, and CTG repeat size was quantified in blood lymphocytes. RESULTS: Patients with DM-1 showed impaired recognition of facial emotions compared with controls. A significant negative correlation was found between total score of emotion recognition in a forced choice task and CTG repeat size. Furthermore, specific cognitive functions (vocabulary, visuospatial construction ability, and speed) and personality dimensions (reward dependence and cooperativeness) correlated with scores on the forced choice emotion recognition task. CONCLUSION: These findings revealed a CTG repeat dependent facial emotion recognition deficit in the DM-1 group, which was associated with specific neuropsychological functions. Furthermore, a correlation was found between facial emotional recognition ability and personality dimensions associated with sociability. This adds a new clinically relevant dimension in the cognitive deficits associated with DM-1.

Adult↗
PubMed2005

Reduction of common synaptic drive to ankle dorsiflexor motoneurons during walking in patients with spinal cord lesion.

It is possible to obtain information about the synaptic drive to motoneurons during walking by analyzing motor-unit coupling in the time and frequency domains. The purpose of the present study was to compare motor-unit coupling during walking in healthy subjects and patients with incomplete spinal cord lesion to obtain evidence of differences in the motoneuronal drive that result from the lesion. Such information is of importance for development of new strategies for gait restoration. Twenty patients with incomplete spinal cord lesion (SCL) participated in the study. Control experiments were performed in 11 healthy subjects. In all healthy subjects, short-term synchronization was evident in the discharge of tibialis anterior (TA) motor units during the swing phase of treadmill walking. This was identified from the presence of a narrow central peak in cumulant densities constructed from paired EMG recordings and from the presence of significant coherence between these signals in the 10- to 20-Hz band. Such indicators of short-term synchrony were either absent or very small in the patient group. The relationship between the amount of short-term synchrony and the magnitude of the 10- to 20-Hz coherence in the patients is discussed in relation to gait ability. It is suggested that supraspinal drive to the spinal cord is responsible for short-term synchrony and coherence in the 10- to 20-Hz frequency band during walking in healthy subjects. Absence or reduction of these features may serve as physiological markers of impaired supraspinal control of gait in SCL patients. Such markers could have diagnostic and prognostic value in relation to the recovery of locomotion in patients with central motor lesions.

Action Potentials↗
PubMed2005

Temperament and character in patients with classical myotonic dystrophy type 1 (DM-1).

This study was designed to investigate personality in classical Myotonic Dystrophy (DM-1). Forty-six patients with DM-1 (25 women and 21 men), 31 healthy controls and 37 subjects in a contrast group, consisting of patients with other muscle disorders (spinal muscular atrophy, facioscapulohumeral dystrophy and limb girdle muscular dystrophy), completed the Temperament and Character Inventory (TCI) (Cloninger, 1994). We aimed to establish whether CTG triplet repeat size correlated with ratings of personality dimensions in the TCI. The DM-1 patients scored significantly higher on the TCI dimension Harm avoidance and lower on Persistence, Self-directedness and Cooperativeness. Signs of a personality disorder were found in 20% of the DM-1 patients. No correlation was found between the number of CTG repeats and scores in the TCI. This study indicates deviant personality in classical DM-1 regarding temperament and character, both in comparison to healthy controls and to patients with other muscle disorders with no known brain disorder.

Adolescent↗
PubMed2005

Non-invasive real-time measurements of cardiac vagal tone in dogs with cardiac disease.

In dogs with spontaneous heart disease, an electronically generated measurement of cardiac vagal tone, the cardiac index of parasympathetic activity, was a sensitive, simple and inexpensive measure of the severity of heart failure. Dogs with cardiac disease and an index score less than 3 were at 15.8 (95 per cent confidence interval 2.9 to 87.2) times the risk of dying within a year than those with a score of 3 and over. The measurement of the index provided an objective and reliable beat-by-beat measurement of cardiac vagal tone, which was prognostically useful in dogs with heart disease.

Animals↗
PubMed2005

Breast cancer risk by age at birth, time since birth and time intervals between births: exploring interaction effects.

In a Norwegian, prospective study we investigated breast cancer risk in relation to age at, and time since, childbirth, and whether the timing of births modified the risk pattern after delivery. A total of 23,890 women of parity 5 or less were diagnosed with breast cancer during follow-up of 1.7 million women at ages 20-74 years. Results, based on Poisson regression analyses of person-years at risk, showed long-term protective effects of the first, as well as subsequent, pregnancies and that these were preceded by a short-term increase in risk. The magnitude and timing of this adverse effect differed somewhat by birth order, maternal age at delivery and birth spacing. No transient increase in risk was seen shortly after a first birth below age 25 years, but an early first birth did not prevent a transient increase in risk after subsequent births. In general, the magnitude of the adverse effect was strongest after pregnancies at age 30 years or older. A wide birth interval was also related to a more pronounced adverse effect. Increasing maternal age at the first and second childbirth was associated with an increase in risk in the long run, whereas no such long-term effect was seen with age at higher order births.

Adult↗
PubMed2005

Study of the reactivity and in vitro bioactivity of Sr-substituted alpha-TCP cements.

In this study the effect of strontium substitution on the hydrolysis of alpha -tricalcium phosphate (alpha-TCP) toward the formation of calcium deficient hydroxyapatite (CDHA) was investigated. For that purpose substituted alpha-TCP powders with 1, 5 and 10 mol% Sr substitution for Ca were synthesized by reacting at 1500 degrees C stoichiometric amounts of CaCO(3), SrCO(3), and Ca(2)P(2)O(7), followed by rapid quenching in air. XRD analysis of the powders revealed the presence of alpha-TCP (traces of beta-TCP) with enlarged unit cell volume at increased Sr contents, indicating the incorporation of Sr in the crystal structure. Strontium was also incorporated in the apatite phase as revealed by XRD analysis of the set cements. The hydrolysis of milled alpha-SrTCP powders and a pure alpha-TCP (control) was monitored by isothermal calorimetry and the compressive strength of set cements was tested. The results showed a decrease in the reactivity with increasing Sr content and similar final mechanical strength within the Sr series, though lower than the control. The in vitro bioactivity of the set cements after soaking in simulated body fluid for 4 weeks was also tested. The formation of a bone-like apatite layer on the surface of the set cements indicated a potential in vivo bioactivity.

Biocompatible Materials↗
PubMed2005

ADHD symptoms and insistence on sameness in Prader-Willi syndrome.

BACKGROUND: Apart from a pervasive eating disorder, the Prader-Willi (PWS) syndrome is characterized by a distinct behavioural profile comprising maladaptive behaviours, obsessive-compulsive traits and skin picking, all included in the PWS behavioural phenotype. In this study, we present a further delineation of this characteristic behavioural profile by screening for indices of executive dysfunctions related to attention-deficit/hyperactivity disorder (ADHD), immature compulsive-like adherence to sameness and skin picking, and how these features aggregate into symptom constellations in children and adolescents with PWS. METHOD: Parents of 58 individuals with PWS (aged 5-18 years) participated by completing Childhood Routines Inventory (CRI) and Conners' Parent Rating Scale (CPRS-48). RESULTS: Results showed that indices of ADHD and excessive insistence on sameness were common, comorbid and of early onset. They were both associated with conduct problems. Skin picking, appearing as a single and comorbid symptom, was less associated with childlike compulsions and ADHD-related problems. CONCLUSIONS: Findings are discussed in terms of further research in executive dysfunctions in PWS.

Adolescent↗
PubMed2005

The Goteborg MCI study: mild cognitive impairment is a heterogeneous condition.

BACKGROUND: Mild cognitive impairment (MCI) has been considered a transitional state between normal aging and dementia, characterised by memory impairment but normal general cognitive functioning. Recently other cognitive deficits have been reported. This has led to a modification of MCI criteria. OBJECTIVE: To examine which neuropsychological tests most clearly distinguish MCI subjects from normal controls. METHODS: 112 consecutive MCI subjects and 35 controls were included in the study. The diagnosis of MCI was based on an objective history of cognitive decline and a neuropsychiatric examination, comprising instruments STEP, I-Flex, MMSE, and CDR. Participants were examined with 21 neuropsychological tests in the cognitive domains speed/attention, memory and learning, visuospatial function, language, and executive function. RESULTS: Controls were significantly older. No differences were found in education or general intellectual capacity. Controls performed significantly better than MCI on tests within all five cognitive domains. The clearest differences were seen on language tests, followed by executive function, and learning and memory. Only two subjects (1.8%) were purely amnestic; 17% showed no impairment compared with controls, with a cut off of 1.5 SD below age mean. These subjects were better educated and performed significantly better on measures of general cognitive capacity. CONCLUSIONS: The results illustrate the heterogeneity of MCI, with a significant degree of impairment in all five cognitive domains. When examined with a comprehensive neuropsychological battery, very few subjects had an isolated memory impairment.

Aged↗
PubMed2004

BRCA1 mutations in ovarian cancer and borderline tumours in Norway: a nested case-control study.

The aims of the present study were to find the frequency of the most common BRCA1 mutations in women with ovarian tumours identified from a population-based cancer registry and in the general population, to estimate the relative risk of ovarian tumours among the mutation carriers, and to explore the value of using CA125 as a prediagnostic test. The study was designed as a nested case-control study within a cohort mainly consisting of participants in population-based health examinations. The data files of The Cancer Registry of Norway and the Janus serum bank were linked to identify cases with ovarian cancer and borderline tumours. Hereditary BRCA1 mutations were determined using archived serum samples and capillary electrophoresis. Altogether 478 ovarian cancer patients and 190 patients with borderline tumours were identified, and 1421 and 568 matching controls were selected. Odds ratios (OR) of developing ovarian cancer and borderline tumours in the presence of BRCA1 mutations and CA125 level were derived from conditional logistic regression models. Among the 478 ovarian cancer patients, 19 BRCA1 mutations were identified (1675delA, 1135insA, 816delGT and 3347delAG), none among the patients with borderline tumours. Only two of the 1989 controls were BRCA1 mutation carriers (0.10%). The risk of ovarian cancer among the mutation carriers was strongly elevated (OR=29, 95% CI=6.6-120). CA125 was a marker for ovarian cancer, but the sensitivity was low. This study showed that BRCA1 mutation carriers have a very high risk of ovarian cancer. However, since the prevalence of BRCA1 mutations in the Norwegian population was low, the proportion of ovarian cancers due to BRCA1 mutations seemed to be low, about 4%. The sensitivity of using CA125 only as a screening test for ovarian cancer was low.

Adult↗
PubMed2004

[Use of information on nosocomial outbreaks for infection control].

Outbreaks of nosocomial infections can be associated with significant morbidity in the patients involved and require time, effort, and resources. In addition, they may lead to panic reactions among health care workers and patients as well as the community. However, their systematic analysis can contribute to knowledge about the sources and transmission of nosocomial infections and the best methods for prevention. Furthermore, the results of outbreak investigations may serve as a valuable tool for education. That is why a systematic register of nosocomial outbreaks would be a very useful instrument for people working in the field of nosocomial infection control. This article describes the need for a systematic collection of outbreaks published in the literature and an available possibility for filling this gap.

Adult↗
PubMed2004

Temperament in the rat: sex differences and hormonal influences on harm avoidance and novelty seeking.

This study showed large and consistent individual differences in 64 rats (32 males) in the hole board and canopy test, which are considered to measure exploration and anxiety, respectively. Nonestrous females were more active than males and nose poked more in the hole board. In the canopy test, nonestrous females, compared with males, showed greater intraindividual variability in time spent outside the protective canopy. Estrous females spent significantly more time outside the canopy. Gonadectomy reduced nose poking in males and hole board locomotion in both sexes. Principal-components analysis disclosed 2 temperamental dimensions reflecting harm avoidance and novelty seeking. More males had high levels of psychometric harm avoidance, and fewer males than females had a low-harm-avoidance/high-novelty-seeking, sanguine profile.

Adrenalectomy↗
PubMed2004

The genes encoding bovine SP-A, SP-D, MBL-A, conglutinin, CL-43 and CL-46 form a distinct collectin locus on Bos taurus chromosome 28 (BTA28) at position q.1.8-1.9.

Collectins are a group of C-type lectins involved in the innate immune system, where they mediate and modulate clearance of pathogens. The health status of cattle is of major economical and ethical concern; therefore, the study of bovine collectins is of importance. The collectins conglutinin, CL-43 and CL-46 are only present in Bovidae and the characterization of their genes indicates that they are structural descendants of another collectin, lung surfactant protein D (SP-D). In this study, we assembled BAC clones into a contig spanning 330-1150 kb, which includes the bovine genes encoding the collectins SP-A (SFTPA), SP-D (SFTPD), mannan-binding lectin A (MBL1), CL-43 (COLEC9), CL-46 (COLEC13) and conglutinin (COLEC8). In the same contig, we also identified a gene that potentially encodes a novel conglutinin-like collectin (COLEC14). The arrangement of STFPA, SFTPD and MBL1 is homologous to the organization found in humans and mice, whereas the Bovidae-specific collectin genes, COLEC8, COLEC9 and COLEC13, extend from SFTPD. Proximal to the collectin locus at BTA28q1.8-1.9, and included in the contig, we found the microsatellite IDVGA8, which may be a valuable marker for tracking polymorphisms in the linked collectin genes.

Amino Acid Sequence↗
PubMed2004

Microvessel density compared with the Chalkley count in a prognostic study of angiogenesis in breast cancer patients.

AIMS: Evaluation of angiogenesis by intratumoral vessel profiles can be performed by different methods. The aim of this study was to investigate the prognostic value of estimates obtained by the intratumoral microvessel density (MVD) method and then to compare with corresponding estimates obtained by the Chalkley method. METHODS AND RESULTS: A total of 330 patients treated for primary, unilateral, invasive breast carcinoma were included. The median follow-up time was 14 years and 4 months. The microvessels were immunohistochemically stained by antibodies to CD34. MVD was not significantly correlated with any clinicopathological variables. By univariate analysis, MVD showed no prognostic value with regard to recurrence-free survival (RFS) or overall survival (OS), while the Chalkley count had significant prognostic value (P < 0.0001; RFS and OS). In the Cox multivariate analysis, MVD had no prognostic impact [median HR [confidence interval (CI)] was 0.93 [0.66, 1.32] for RFS; and HR [CI] was 0.86 [0.62, 1.19] for OS], while the Chalkley count [median HR (CI) was 2.12 (1.48, 3.06) for RFS; and HR (CI) was 1.71 (1.23, 2.37) for OS] provided independent prognostic value when adjusted for age, menopausal status, axillary lymph node status, tumour size, histological grade, adjuvant systemic treatment and radiation therapy. In comparing the results obtained by MVD in our study with those from other published studies we find good agreement. CONCLUSIONS: The Chalkley count technique seems to be preferable for estimating angiogenesis with regard to the prognostic stratification of breast cancer patients, based on its strong prognostic impact, and acceptable reproducibility.

Age Distribution↗
PubMed2003

Cardiovascular regulation in the period preceding vasovagal syncope in conscious humans.

To study cardiovascular control in the period leading to vasovagal syncope we monitored beat-to-beat blood pressure, heart rate (HR) and forearm blood flow in 14 patients with posturally related syncope, from supine through to tilt-induced pre-syncope. Signals of arterial blood pressure (BP) from a Finapres photoplethysmograph and an electrocardiograph (ECG) were fed into a NeuroScope system for continuous analysis. Non-invasive indices of cardiac vagal tone (CVT) and cardiac sensitivity to baroreflex (CSB) were derived on a beat-to-beat basis from these data. Brachial vascular resistance (VR) was assessed intermittently from brachial blood flow velocity (Doppler ultrasound) divided by mean arterial pressure (MAP). Patients underwent a progressive orthostatic stress test, which continued to pre-syncope and consisted of 20 min head-up tilt (HUT) at 60 deg, 10 min combined HUT and lower body suction (LBNP) at -20 mmHg followed by LBNP at -40 mmHg. Pre-syncope was defined as a fall in BP to below 80 mmHg systolic accompanied by symptoms. Baseline supine values were: MAP (means +/- S.E.M.) 84.9 +/- 3.2 mmHg; HR, 63.9 +/- 3.2 beats min-1; CVT, 10.8 +/- 2.6 (arbitrary units) and CSB, 8.2 +/- 1.6 ms mmHg-1. HUT alone provoked pre-syncope in 30 % of the patients whilst the remaining 70 % required LBNP. The cardiovascular responses leading to pre-syncope can be described in four phases. Phase 1, full compensation: where VR increased by 70.9 +/- 0.9 %, MAP was 89.2 +/- 3.8 mmHg and HR was 74.8 +/- 3.2 beats min-1 but CVT decreased to 3.5 +/- 0.5 units and CSB to 2.7 +/- 0.4 ms mmHg-1. Phase 2, tachycardia: a progressive increase in heart rate peaking at 104.2 +/- 5.1 beats min-1. Phase 3, instability: characterised by oscillations in BP and also often in HR; CVT and CSB also decreased to their lowest levels. Phase 4, pre-syncope: characterised by sudden decreases in arterial blood pressure and heart rate associated with intensification of the symptoms of pre-syncope. This study has given a clearer picture of the cardiovascular events leading up to pre-syncope. However, the mechanisms behind what causes a fully compensated system suddenly to become unstable remain unknown.

Adult↗