PubMed Health⌕ Search

Biomedical subjects

A M Hansen

Publications and source records attributed to A M Hansen.

At least 19 recordsLinked to original sources
PubMed2005

Long-term stability of salivary cortisol.

The measurement of salivary cortisol provides a simple, non-invasive, and stress-free measure frequently used in studies of the hypothalamic-pituitary-adrenal axis activity. In research projects, samples are often required to be stored for longer periods of time either because of the protocol of the project or because of lack of funding for analysis. The aim of the present study was to explore the effects of long-term storage of samples on the amounts of measurable cortisol. Ten pools of saliva were collected on polyester Salivette tampons from five subjects. After centrifugation the samples were either stored in small vials or spiked to polyester Salivette tampons before analysis for cortisol using Spectria RIA kits. The effects of storage were evaluated by a linear regression model (mixed procedure) on a logarithmic scale. No effects on cortisol concentrations were found after storage of saliva at 5 degrees C for up to 3 months or at -20 degrees C and -80 degrees C for up to one year. In contrast, concentrations of cortisol were found to decrease by 9.2% (95% confidence interval (CI): 3.8%; 14.3%) per month in samples stored at room temperature. Repeated freezing and thawing of samples up to four times before analysis did not affect the measured concentrations of cortisol. The coefficient of residual variation (CVresid) for samples stored on Salivette tampons were twice the CVresid for samples stored in separate vials after centrifugation. In conclusion, centrifuged saliva samples for analysis of cortisol may be stored at 5 degrees C for up to 3 months or at -20 degrees C or -80 degrees C for at least one year. However, long-term storage at room temperature cannot be recommended. Repeated cycles of freezing and thawing did not appear to affect the concentrations of cortisol.

Freezing↗
PubMed2004

Catabolism of leucine to branched-chain fatty acids in Staphylococcus xylosus.

AIMS: Staphylococcus xylosus is an important starter culture in the production of flavours from the branched-chain amino acids leucine, valine and isoleucine in fermented meat products. The sensorially most important flavour compounds are the branched-chain aldehydes and acids derived from the corresponding amino acids and this paper intends to perspectivate these flavour compounds in the context of leucine metabolism. METHODS AND RESULTS: GC and GC/MS analysis combined with stable isotope labelling was used to study leucine catabolism. This amino acid together with valine and isoleucine was used as precursors for the production of branched-chain fatty acids for cell membrane biosynthesis during growth. A 83.3% of the cellular fatty acids were branched. The dominating fatty acid was anteiso-C(15:0) that constituted 55% of the fatty acids. A pyridoxal 5'-phosphate and alpha-ketoacid dependent reaction catalysed the deamination of leucine, valine and isoleucine into their corresponding alpha-ketoacids. As alpha-amino group acceptor alpha-keto-beta-methylvaleric acid and alpha-ketoisovaleric acid was much more efficient than alpha-ketoglutarate. The sensorially and metabolic key intermediate on the pathway to the branched-chain fatty acids, 3-methylbutanoic acid was produced from leucine at the onset of the stationary growth phase and then, when the growth medium became scarce in leucine, from the oxidation of glucose via pyruvate. CONCLUSIONS: This paper demonstrates that the sensorially important branched-chain aldehydes and acids are important intermediates on the metabolic route leading to branched-chain fatty acids for cell membrane biosynthesis. SIGNIFICANCE AND IMPACT OF THE STUDY: The metabolic information obtained is extremely important in connection with a future biotechnological design of starter cultures for production of fermented meat.

Cell Membrane↗
PubMed2003

Evaluation, including effects of storage and repeated freezing and thawing, of a method for measurement of urinary creatinine.

The aims of this study were to elucidate to what extent storage and repeated freezing and thawing influenced the concentration of creatinine in urine samples and to evaluate the method for determination of creatinine in urine. The creatinine method was based on the well-known Jaffe's reaction and measured on a COBAS Mira autoanalyser from Roche. The main findings were that samples for analysis of creatinine should be kept at a temperature of -20 degrees C or lower and frozen and thawed only once. The limit of detection, determined as 3 x SD of 20 determinations of a sample at a low concentration (6.1 mmol/L), was 0.3 mmol/L, and the recovery of a certified reference material was 97%. The relative precision at 3.15 mmol/L was 2.3%. It was concluded that the method is appropriate for measurement of urinary creatinine.

Clinical Laboratory Techniques↗
PubMed2003

Evaluation of a radioimmunoassay and establishment of a reference interval for salivary cortisol in healthy subjects in Denmark.

A commercial radioimmunoassay (RA) for salivary cortisol was evaluated using certified reference material in water and spiked to pooled saliva in the range 2.1-89.1 nmol/L. A variance component model for describing the effects of age, body mass index (BMI), diurnal variation, gender, days of sick leave during the past year, and smoking habits was established. Reference intervals for salivary cortisol in 120 healthy individuals performing their routine work were established according to the International Union of Pure and Applied Chemistry (IUPAC) and the International Federation of Clinical Chemistry (IFCC). The method evaluation of the certified reference material in water did not show any bias of the method, i.e. recovery was 97% [CI: 94%; 100.9%]. LOD (detection limit) was 1.59 nmol/L. The ratio between analytical and within-subject variation (CVa/CVi) was 0.14, indicating that the method was adequate for measurement in healthy subjects. Reference intervals were estimated to be from 3.6 to 35.1 nmol/L for samples at the time of awakening (05.27-07.27), 7.6-39.4 nmol/L for peak level in saliva samples collected 20 min after awakening (05.47-07.47), and LOD 10.3 nmol/L for late afternoon samples (17.00-19.00). Reactivity (increase from awakening to 20 min after awakening) was estimated to be 82% [CI: -179; 345%] and recovery (decrease from 20 min after awakening to 18.00) to be 80% [CI: 51; 109%]. Eighteen percent of the subjects showed a decrease in cortisol in saliva from awakening to 20 min after awakening. Salivary cortisol was not affected by age, body mass index, gender, smoking habits or days of sick leave during the past year.

Adult↗
PubMed2001

Reference interval and subject variation in excretion of urinary metabolites of nicotine from non-smoking healthy subjects in Denmark.

BACKGROUND: Passive smoking has been found to be a respiratory health hazard in humans. The present study describes the calculation of a reference interval for urinary nicotine metabolites calculated as cotinine equivalents on the basis of 72 non-smokers exposed to tobacco smoke less than 25% of the day. METHODS: Twenty subjects (passive smokers) exposed to tobacco smoke more than 25% of the day (subjectively assessed) and 32 smokers were used to validate the estimated reference interval. Urine samples were collected three times during the day approximately at 06.30, 17.00 and 22.45 h. RESULTS: Within-subject variation was found to be 89.4, 72.6, and 79.2% and between-subject variation was found to be 64.5, 64.2, and 36.1%. No gender difference could be demonstrated. In general all subjects showed increased concentrations in the afternoon and evening samples compared to the morning samples. Parametric reference interval for excretion of nicotine metabolites in urine from non-smokers was established according to International Union of Pure and Applied Chemistry (IUPAC) and International Federation for Clinical Chemistry (IFCC) for use of risk assessment of exposure to tobacco smoke. The reference interval for urinary cotinine was estimated to be 1.1-90.0 micromol/mol creatinine in morning samples from non-smokers. An intercomparison between the radioimmunoassay (RIA) method used for determination of nicotine metabolites and a gas chromatography-mass spectrometry (GC-MS) method for determination of cotinine was carried out on 27 samples from non-smokers and smokers. Results obtained from the RIA method showed 2.84 [confidence interval (CI): 2.50; 3.18] times higher results compared to the GC-MS method. A linear correlation between the two methods was demonstrated (rho=0.96). CONCLUSION: The RIA method is rapid and adequate for clinical use in the assessment of exposure to tobacco smoke, i.e. ratio between CV(a)/CV(ti) was<0.50.

Adult↗
PubMed2001

Cortisol in urine and saliva: relations to the intima media thickness, IMT.

OBJECTIVE: The objective of the study was to analyse the relations between excretion of cortisol in urine and saliva and the intima media thickness (IMT) of the artery carotis communis. DESIGN AND METHODS: In a cross-sectional study, 121 healthy participants completed a comprehensive questionnaire. Additionally, three samples of urine and four samples of saliva were collected in the 24 h before the examination, which included an ultrasound examination of the artery carotis communis, measuring height, weight, hip and waist width, blood pressure after 10 min of rest, and analysis of blood samples for cholesterol, high density lipoprotein (HDL)-cholesterol, and HbA(1c). The highest average of three measurements of IMT immediately before cartosis bulbous from either left or right side was used in the analyses as the dependent variable IMT. RESULTS: Values of cortisol in urine adjusted for creatinine were not related to IMT, but the level of salivary cortisol 1 h after awakening and the reactivity in salivary cortisol the first hour after awakening were significantly associated with IMT in women i.e. high cortisol was associated with low IMT. This result remained significant in multiple regression analysis including age, body mass index (BMI), cholesterol, HbA(1c), and alcohol. CONCLUSION: The reactivity in salivary cortisol the first hour in the morning might be used in research relating to stress, hormonal changes and early atherosclerosis.

Adult↗
PubMed2001

Reference intervals and variation for urinary epinephrine, norepinephrine and cortisol in healthy men and women in Denmark.

Reference intervals for urinary epinephrine, norepinephrine and cortisol in 120 healthy individuals performing their routine work were established according to the International Union of Pure and Applied Chemistry (IUPAC) and the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) for use in the risk assessment of exposure to occupational stress. Reference intervals were established for three different times of the day: in morning samples (05.45-07.15) the limit of detection (LOD) was 2.10 micromol epinephrine/mol creatinine (82 women) and 2.86 micromol epinephrine/mol creatinine (37 men), and the reference interval was 3.6-29.1 micromol norepinephrine/mol creatinine and 2.3-52.8 micromol cortisol/mol creatinine (119 women and men); in afternoon samples (15.30-18.30) the reference interval was 0.64-10.8 micromol epinephrine/mol creatinine (82 women), 1.20-11.2 micromol/epinephrine/mol creatinine (36 men), 11.0-54.1 micromol/ norepinephrine/mol creatinine and LOD was 42.4 micromol cortisol/mol creatinine (117 women and men); in evening samples (21.45-23.45) LOD was 8.66 micromol epinephrine/mol creatinine (81 women) and 7.99 micromol/epinephrine/mol creatinine (36 men), the reference interval was 11.0-54.1 micromol norepinephrine/mol creatinine, and LOD was 42.4 micromol cortisol/mol creatinine (117 women and men). A variance component model for describing the effects of age, body mass index (BMI), diurnal variation, gender, days of sick leave during past year and smoking habits was established. Women showed a higher morning value but excreted lower amounts of epinephrine during the day as compared to men. No gender differences could be demonstrated for the excretion of norepinephrine and cortisol. Excretion of epinephrine and norepinephrine increased with smoking and decreased with increased BMI. No effects were observed in the excretion of cortisol.

Adult↗
PubMed2000

Tissue distribution of indoleamine 2,3-dioxygenase in normal and malaria-infected tissue.

An immunohistochemical method was developed, using a polyclonal antibody, to detect the enzyme indoleamine 2,3-dioxygenase (IDO) in normal and malaria-infected tissue. Plasmodium berghei ANKA, a cerebral malaria (CM) model, and P. berghei K173, a non-cerebral malaria (NCM) model, were used. It was found that vascular endothelial cells were the primary site of IDO expression in both models of malaria infection and that this response was systemic, with the vascular endothelium of brain, heart, lung, spleen and uterus all staining positive. These results suggest that IDO is part of a systemic host response to parasite infection. Although high levels of IDO production alone may not cause pathology, it is possible that when its production is combined with other features of CM, such as breakdown of the blood-brain barrier (BBB), metabolites of the kynurenine pathway may be able to influence the otherwise tightly regulated, immunologically privileged site of the CNS and cause some of the symptoms and pathology observed.

Animals↗
PubMed2000

Association between plasma testosterone and work-related neck and shoulder disorders among female workers.

OBJECTIVES: The aims were to study the association between anabolic hormone testosterone in plasma and the presence of musculoskeletal disorders among female workers and to study the association between changes in testosterone and changes in musculoskeletal complaints. METHODS: In a cross-sectional design 145 women from 2 different industries filled out questionnaires about current musculoskeletal complaints, participated in a clinical examination of the neck and upper extremities, and gave a blood sample for the analysis of free testosterone in plasma. Individual characteristics, psychosocial job factors, and stress reactions were evaluated by questionnaires. In a follow-up study a subgroup of 73 sewing machine operators from the cross-sectional study was reexamined after 1 year. RESULTS: The group of women with clinically verified neck or shoulder disorders had significantly lower plasma testosterone than the women with no disorders. Furthermore, the testosterone level showed a negative association with age and a positive association with smoking and body mass index. Changes in pain status or clinically diagnosed musculoskeletal disorders were not associated with changes in testosterone levels. However, this finding may well be due to a strong plant influence in that marked changes in testosterone levels were observed for 2 of the 3 participating plants. CONCLUSIONS: There is some indication of an association between musculoskeletal disorders in the neck and shoulders and a low level of free plasma testosterone. The study failed to clarify the associations found between changes in testosterone and changes in musculoskeletal complaints over time.

Adult↗
PubMed2000

Seasonal and biological variation of blood concentrations of total cholesterol, dehydroepiandrosterone sulfate, hemoglobin A(1c), IgA, prolactin, and free testosterone in healthy women.

BACKGROUND: Concentrations of physiological response variables fluctuate over time. The present study describes within-day and seasonal fluctuations for total cholesterol, dehydroepiandrosterone sulfate (DHEA-S), hemoglobin A(1c) (HbA(1c)), IgA, prolactin, and free testosterone in blood, and estimates within- (CV(i)) and between-subject (CV(g)) CVs for healthy women. In addition, the index of individuality, prediction intervals, and power calculations were derived. METHODS: A total of 21 healthy female subjects participated in the study. Using a random effects analysis of variance, we estimated CV(g) and total within-subject variation (CV(ti)), i.e., the combined within-subject and analytical variation, from logarithmically transformed data. Analytical variation was subtracted from CV(ti) to give CV(i). CV(i) was estimated from samples taken monthly during 1 year (CV(iy)), weekly during 1 month (CV(im)), and six times within 1 day (CV(id)). RESULTS: A cyclic seasonal variation was demonstrated for total cholesterol, DHEA-S, HbA(1c), prolactin, and free testosterone. Within-day variation was shown for prolactin and free testosterone. The overall mean values for the group and the variability (CV(iy) and CV(g)) were: 5.1 mmol/L, 13% [corrected], and 12% [corrected] for total cholesterol; 6.6 micromol/L, 20% [corrected], and 49% [corrected] for DHEA-S; 30% [corrected], 7.0% [corrected], and 7.5% [corrected] for HbA(1c)/hemoglobin(total); 2.1 g/L, 5.9%, and 13% for IgA; 136 mIU/L, 58% [corrected], and 63% [corrected] for prolactin; and 5.4 pmol/L, 55% [corrected], and 68% [corrected] for free testosterone. CONCLUSIONS: Collecting samples at specific hours of the day or times of the year may reduce high biological variation. Alternatively, the number of individuals may be increased and a paired study design chosen to obtain adequate statistical power.

Adult↗
PubMed1996

Exposure of Danish children to traffic exhaust fumes.

This exposure study addresses the validity of the exposure assessment method of an epidemiological study of traffic-related air pollution and childhood cancer. In particular, this paper concerns the question of whether the concentration of nitrogen dioxide (NO2) outside the front door is a valid marker of the exposure of the child living at the address. The study includes 100 children living on streets with dense traffic in central parts of Copenhagen and 100 children living in rural areas. Preliminary results, based on 25% of the study subjects, suggest that both the outdoor NO2-concentration and the exposure of the children are two to three times higher in Copenhagen than in the rural districts. Moreover, the results suggest that the NO2-concentration outside the front door is a poor marker of the exposure of the children in Copenhagen, but a marker of some relevance for the exposure of the children in rural districts. The preliminary results must be treated with caution, as among other things, the analysis did not consider seasonal changes and indoor NO2-sources such as passive smoking, candles, and gas appliances.

Air Pollutants↗
PubMed1996

[Formaldehyde in the occupational environment. A possible cause of chemically induced reactive arthritis].

A case is presented of a farmer aged 33 years who developed polyarthritis four to five days after having used formaldehyde for fumigation of his piggery. The farmer was admitted to the General Hospital in Herning for treatment. The course of the treatment was several months. Furthermore, two farm assistants and a bricklayer were exposed to formaldehyde in the piggery. They developed acute intoxication symptoms and, a few days after the exposure, arthralgia. There was no other collective exposure. Apart from the formaldehyde, there was a great amount of water in the piggery, leading to the conclusion that the exposure was due to the formaldehyde being absorbed in the water with following evaporation. In conclusion, a relationship between these particular circumstances of formaldehyde exposure and reactive arthritis is found to be likely.

Adult↗
PubMed1996

Urinary 1-hydroxypyrene, a PAH biomarker in foundry workers.

Exposure to PAH in foundry workers has been studied by urinary 1-hydroxypyrene (HPU) levels, quantitatively measured by reversed phase HPLC. Seventy male foundry workers and 68 matched controls were investigated. Polycyclic aromatic hydrocarbon (PAH) exposure was defined by 17 breathing zone hygienic samples, consisting of 16 selected PAH compounds. Mean total PAH concentration (SD) was 10.40 (4.04) mu g/m3. A multiple regression model of tobacco consumption, age, airborne PAH-exposure and foundry work on log HPU showed a significant correlation, p < 0.001, r2 = 0.69. Only foundry work (p < 0.0001) and airborne PAH exposure (p = 0.0478) contributed significantly to the model. These data suggest that HPU is a sensitive biomarker for low-dose PAH exposure.

Adult↗
PubMed1995

Collection of domestic waste. Review of occupational health problems and their possible causes.

During the last decade, a growing interest in recycling of domestic waste has emerged, and action plans to increase the recycling of domestic waste have been agreed by many governments. A common feature of these plans is the implementation of new systems and equipment for the collection of domestic waste which has been separated at source. However, only limited information exists on possible occupational health problems related to such new systems. Occupational accidents are very frequent among waste collectors. Based on current knowledge, it appears that the risk factors should be considered as an integrated entity, i.e. technical factors (poor accessibility to the waste, design of equipment) may act in concert with high working rate, visual fatigue due to poor illumination and perhaps muscle fatigue due to high work load. Musculoskeletal problems are also common among waste collectors. A good deal of knowledge has accumulated on mechanical load on the spine and energetic load on the cardio-pulmonary system in relation to the handling of waste bags, bins, domestic containers and large containers. However, epidemiologic studies with exposure classification based on field measurement are needed, both to further identify high risk work conditions and to provide a detailed basis for the establishment of occupational exposure limits for mechanical and energetic load particularly in relation to pulling, pushing and tilting of containers. In 1975, an excess risk for chronic bronchitis was reported for waste collectors in Geneva (Rufèner-Press et al., 1975) and data from the Danish Registry of Occupational Accidents and Diseases also indicate an excess risk for pulmonary problems among waste collectors compared with the total work force. Surprisingly few measurements of potentially hazardous airborne exposures have been performed, and the causality of work-related pulmonary problems among waste collectors is unknown. Recent studies have indicated that implementation of some new waste collection systems may result in an increased risk of occupational health problems. High incidence rates of gastrointestinal problems, irritation of the eye and skin, and perhaps symptoms of organic dust toxic syndrome (influenza-like symptoms, cough, muscle pains, fever, fatigue, headache) have been reported among workers collecting the biodegradable fraction of domestic waste. The few data available on exposure to bio-aerosols and volatile compounds have indicated that these waste collectors may be simultaneously exposed to multiple agents such as dust containing bacteria, endotoxin, mould spores, glucans, volatile organic compounds, and diesel exhaust. Several studies have reported similar health problems as well as high incidence rates of pulmonary disease among workers at plants recycling domestic waste.(ABSTRACT TRUNCATED AT 400 WORDS)

Accidents, Occupational↗
PubMed1995

Sorting and recycling of domestic waste. Review of occupational health problems and their possible causes.

In order to reduce the strain on the environment from the deposition of waste in landfills and combustion at incineration plants, several governments throughout the industrialized world have planned greatly increased recycling of domestic waste by the turn of the millennium. To implement the plans, new waste recycling facilities are to be built and the number of workers involved in waste sorting and recycling will increase steadily during the next decade. Several studies have reinforced the hypothesis that exposure to airborne microorganisms and the toxic products thereof are important factors causing a multitude of health problems among workers at waste sorting and recycling plants. Workers at transfer stations, landfills and incineration plants may experience an increased risk of pulmonary disorders and gastrointestinal problems. High concentrations of total airborne dust, bacteria, faecal coliform bacteria and fungal spores have been reported. The concentrations are considered to be sufficiently high to cause adverse health effects. In addition, a high incidence of lower back injuries, probably due to heavy lifting during work, has been reported among workers at landfills and incineration plants. Workers involved in manual sorting of unseparated domestic waste, as well as workers at compost plants experience more or less frequent symptoms of organic dust toxic syndrome (ODTS) (cough, chest-tightness, dyspnoea, influenza-like symptoms such as chills, fever, muscle ache, joint pain, fatigue and headache), gastrointestinal problems such as nausea and diarrhoea, irritation of the skin, eye and mucous membranes of the nose and upper airways, etc. In addition cases of severe occupational pulmonary diseases (asthma, alveolitis, bronchitis) have been reported. Manual sorting of unseparated domestic waste may be associated with exposures to large quantities of airborne bacteria and endotoxin. Several work functions in compost plants can result in very high exposure to airborne fungal spores and thermophilic actinomycetes. At plants sorting separated domestic waste, e.g. the combustible fraction of waste composed of paper, cardboard and plastics, the workers may have an increased risk of gastrointestinal symptoms and irritation of the eyes and skin. At such plants the bioaerosol exposure levels are in general low, but at some work tasks, e.g. manual sorting and work near the balers, exposure levels may occasionally be high enough to be potentially harmful. Workers handling the source-sorted paper or cardboard fraction do not appear to have an elevated risk of occupational health problems related to bioaerosol exposure, and the bioaerosol exposure is generally low.(ABSTRACT TRUNCATED AT 400 WORDS)

Equipment Reuse↗
PubMed1995

Estimation of reference values for urinary 1-hydroxypyrene and alpha-naphthol in Danish workers.

In order to assess environmentally and occupationally related exposures to PAH compounds it is essential to have reference or normal values in human body fluids. The establishment of reliable reference intervals is an absolute pre-requisite in determining relationships between internal PAH exposure in humans and health effects in occupationally exposed workers. In this context the estimation of the biological level of PAH metabolites in urine from reference populations has become increasingly important in the field of environmental and occupational toxicology. The present study describes the calculation of tentative reference values for urinary 1-hydroxypyrene on the basis of two reference populations and for urinary alpha-naphthol on the basis of one reference population in accordance with IFCC recommendations. The study subjects were 115 healthy male workers occupationally exposed to PAH at low levels and 121 reference subjects non-occupationally exposed to PAH. Tentative reference values for urinary 1-hydroxypyrene were estimated. In addition, 236 healthy male workers were used to estimate tentative reference values for urinary alpha-naphthol. The reference populations were described by distribution free one-sided tolerance intervals. The 95% one-sided tolerance limit calculated for 1-hydroxypyrene in urine was 0.053 mumol/mol creatinine for non-occupationally exposed individuals and 0.169 mumol/mol creatinine for low level PAH exposed workers, with the coverage interval (95 +/- 4.5) percent at a probability of 0.95. Thus, the probability was 0.975 that the tolerance interval included at least 90.5% of the distribution. In addition, the probability was 0.025 that the tolerance interval included > 99.5% of the population. The tolerance interval for alpha-naphthol in urine was 5.665 mumol/mol creatinine with the coverage interval (95 +/- 4.5) percent at a probability of 0.95.

Air Pollutants, Occupational↗