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Biomedical subjects

M S Andersen

Publications and source records attributed to M S Andersen.

15 recordsLinked to original sources
PubMed2006

A study of police operated dispatch to acute coronary syndrome cases arising from 112 emergency calls in Aarhus county, Denmark.

BACKGROUND: The accuracy of the Danish police operated "112" emergency call system was studied. Dispatch of the anaesthesiologist staffed mobile emergency care unit (MECU) to acute coronary syndrome (ACS) cases was used as an indicator of accuracy of dispatch to life threatening emergencies. METHODS: This was an observational cohort study of patients given a 112 system report of heart attack and patients with a provisional diagnosis of ACS made on scene by the MECU. Sensitivity, specificity, and positive predictive value with 95% confidence intervals (CI) were calculated. RESULTS: There were 341 reports of "heart attack" and 205 patients with ACS. Sensitivity was 75% (95% CI 68% to 80%) specificity 90% (89% to 92%) and positive predictive value 45% (40% to 50%). CONCLUSION: The accuracy of 112 dispatch of the MECU was found to be moderate. We suggest more training of dispatch staff and medical supervision.

Cohort Studies↗
PubMed2006

Risk factors for colic in horses after general anaesthesia for MRI or nonabdominal surgery: absence of evidence of effect from perianaesthetic morphine.

REASON FOR PERFORMING STUDY: Post anaesthetic colic is a recognised risk of general anaesthesia (GA), but causes are poorly understood. OBJECTIVES: To identify risk factors for development of colic following GA for magnetic resonance imaging (MRI) or nonabdominal surgery and to test whether the use of perianaesthetic morphine was associated with an increased risk of post anaesthetic colic. METHODS: A total of 553 anaesthetic and clinical records of 500 horses anaesthetised at the Animal Health Trust were analysed, 342 (62%) involved MRI and 211 (38%) nonabdominal, predominantly orthopaedic surgery. Multivariable logistic regression analysis was used to examine the association between post anaesthetic colic and explanatory variables, including use of perianaesthetic morphine. RESULTS: Twenty horses (3.6%) developed colic within 7 days of GA. A significantly larger (P = 0.001) proportion of the surgical cases developed post anaesthetic colic (7.1%) compared with MRI cases (1.5%). Having controlled for the effect of MRI/surgeon, there was evidence for a significantly increased risk of colic associated with maintenance of anaesthesia with isoflurane and administration of benzyl penicillin and/or ceftiofur. A reduction in risk of colic was associated with premedication with romifidine, longer duration of anaesthesia and sedation within 2 days of GA. Perianaesthetic morphine administration was not associated with increased risk. CONCLUSIONS: This study identified apparently novel risk factors for colic in horses following GA. Use of morphine was not found, after controlling for other MRI and surgery related risk factors, to be associated with an increased risk. The low prevalence of colic after GA and resulting low study power mean that further larger, multicentre collaborative studies are warranted to corroborate findings in this study. POTENTIAL RELEVANCE: Better knowledge of risk factors should lead to achievable measures to reduce frequency of occurrence.

Anesthesia, General↗
PubMed2005

Risk factors for faecal sand excretion in Icelandic horses.

REASONS FOR PERFORMING STUDY: Sandy soil is often mentioned as a risk factor in the development of sand-related gastrointestinal disease (SGID) in the horse. There are other variables, but few studies confirm any of these. OBJECTIVE: To investigate soil type, pasture quality, feeding practice in the paddock, age, sex and body condition score as risk factors for sand intake in the horse. METHODS: Faeces were collected from 211 Icelandic horses on 19 different studs in Denmark together with soil samples and other potential risk factors. Sand content in faeces determined by a sand sedimentation test was interpreted as evidence of sand intake. Soil types were identified by soil analysis and significance of the data was tested using logistic analysis. RESULTS: Of horses included in the study, 56.4% showed sand in the faeces and 5.7% had more than 5 mm sand as quantified by the rectal sleeve sedimentation test. Soil type had no significant effect when tested as main effect, but there was interaction between soil type and pasture quality. Significant interactions were also found between paddock feeding practice and pasture quality. CONCLUSION: To evaluate the risk of sand intake it is important to consider 3 variables: soil type, pasture quality and feeding practice. Pasture quality was identified as a risk factor of both short and long grass in combination with sandy soil, while clay soil had the lowest risk in these combinations. Feeding practice in the paddock revealed feeding directly on the ground to be a risk factor when there was short (1-5 cm) or no grass. Also, no feeding outdoors increased the risk on pastures with short grass, while this had no effect in paddocks with no grass. More than 50% of all horses investigated in this study had sand in the faeces. POTENTIAL RELEVANCE: The identification of risk factors is an important step towards prevention of SGID. Further research is necessary to determine why some horses exhibit more than 5 mm sand in the sedimentation test and whether this is correlated with geophagic behaviour.

Animal Feed↗
PubMed2001

Pyrite oxidation in unsaturated aquifer sediments. Reaction stoichiometry and rate of oxidation.

The oxidation of pyrite (FeS2) contained in unsaturated aquifer sediment was studied by sediment incubation in gas impermeable polymer laminate bags. Reaction progress was followed over a period of nearly 2 months by monitoring the gas composition within the laminate bag. The gas phase in the incubation bags became depleted in O2 and enriched in CO2 and N2 and was interpreted as due to pyrite oxidation in combination with calcite dissolution. Sediment incubation provides a new method to estimate low rates of pyrite oxidation in unsaturated zone aquifer sediments. Oxidation rates of up to 9.4 x 10(-10) mol FeS2/g x s are measured, and the rates are only weakly correlated with the sediment pyrite content. The reactivity of pyrite, including the inhibition by FeOOH layers formed on its surface, apparently has a major effect on the rate of oxidation. The code PHREEQC 2.0 was used to calculate the reaction stoichiometry and partitioning of gases between the solution and the gas phase. Pyrite oxidation with concurrent calcite dissolution was found to be consistent with the experimental data while organic carbon oxidation was not. The reaction involves changes in the total volume of the gas phase. The reaction scheme predicts the volume of O2 gas consumed to be larger than of CO2 produced. In addition the solubility of CO2 in water is about 30 times larger than of O2 causing a further decrease in total gas volume. The change in total gas volume therefore also depends on the gas/water volume ratio and the lower the ratio the more pronounced the loss of volume will be. Under field conditions the change in total volume may amount up to 20% in the absence of calcite and over 10% in the presence of calcite. Such changes in gas volume during the oxidation of pyrite are expected to result in pressure gradients causing advective transport of gaseous oxygen.

Carbon Dioxide↗
PubMed1996

The Rickettsia prowazekii genome: a random sequence analysis.

We describe here the first general survey of the genomic content and the coding capacity of the 1.1 Mb genome of Rickettsia prowazekii based on an analysis of a total of 200 kb of unique sequence data collected in a random manner. Based on nucleotide distribution profiles, we estimate that the R. prowazekii genome may have a coding density of 60%-70% and that it may contain a total of circa 800 genes. Here, we have tentatively identified and classified 173 of these genes. Our analysis suggests that the R. prowazekii genome is a highly derived, reduced genome that has lost many genes involved in amino acid biosynthetic pathways and regulatory functions. Furthermore, the R. prowazekii genome seems to lack glycolytic genes, but it does contain genes encoding components of the tricarboxylic acid cycle as well as of the electron transport system. We have also encountered a family of homologous genes coding for ATP/ADP translocases, as observed in several mitochondrial genomes. We relate these findings to previous phylogenetic studies that suggest that Rickettsia and mitochondria share a common ancestor.

Base Sequence↗
PubMed1991

Influence of butyrate on lipid metabolism, survival, and differentiation of colon cancer cells.

The present work was designed to study the differentiating effect of butyrate on LS174T cells after modification of their lipids with long-chain fatty acid (LCFA) supplementation. The LCFAs 18:1(n-9), 18:2(n-6), 20:4(n-6), 20:5(n-3), and 22:6(n-3) bound to added to the media of confluent cells for eight days. The fatty acid-to-albumin ratio was 3:1. The concentration of fatty acids in the media was 100 microM. On the last day, half of the flasks were treated with 2 mM butyrate. The data indicate that supplementation with polyunsaturated LCFAs having 20-22 carbon atoms resulted in a significant reduction in cell density and viability, whereas all LCFA supplementation reduced differentiation as measured by alkaline phosphatase activity. Butyrate treatment increased the density, viability, and differentiation of the tumor cells. The effect of butyrate on differentiation was mainly with cells supplemented with 18:1, 20:5, and 22:6. In the absence of LCFA supplementation, butyrate reduced the concentration of 22:5(n-6) in the cellular lipids. Also, butyrate modified the LCFAs incorporated in cells supplemented with 18:2 and 20:5, with changes occurring in 20:5(n-3), 22:5(n-3), and 22:5(n-6). Thus the present study suggests an interaction between butyrate and LCFA on differentiation and LCFA metabolism of human colon cancer cells.

Adenocarcinoma↗
PubMed1987

Mental retardation in a patient with Maroteaux-Lamy.

An 8-year-old boy with Hurler-like traits including severe mental retardation excreted in his urine a pathognomonic amount of dermatan sulfate. Less than 10% residual activity of arylsulfatase B was found in his leucocytes and fibroblasts. Hurler fibroblasts corrected an abnormally high 35SO4-incorporation into acid mucopolysaccharides (MPS) in cultured fibroblasts, whereas Maroteaux-Lamy fibroblasts did not. The patient thus has a rare combination of Maroteaux-Lamy and severe mental retardation.

Child↗
PubMed1981

Variations in tympanograms in children attending group-care during a one-year period.

During a 1-year period, 151 children, 1/2-6 years old, attending group care, were followed by monthly tympanometry in order to describe spontaneous variations in the tympanograms in relation to age and time of the year. Furthermore, the number of spontaneous variations during the year was assessed. Significantly more flat curves were seen in children 1/2-1 year old than in the older age groups, indicating a high frequency of spontaneous remission about the age of 2 years. In all age groups more normal tympanograms were seen during late summer than during the rest of the year. Spontaneous variations in the tympanograms were taking place 2.9 times (mean) during the period of observation. Correlation was found between the presence of catarrh and flat curves. Furthermore, in children greater than or equal to 3 years old, a correlation between case history signs of enlarged adenoids and flat curves lasting for 3 months or more was found. It was concluded that persistence of flat curves in children 1/2-1 (2) years old usually requires no treatment, as spontaneous remission can be expected, whereas persistence of flat curves for greater than or equal to 3 months in children greater than or equal to (2) 3 years old indicates that treatment (adenoidectomy) should be performed.

Acoustic Impedance Tests↗
PubMed1979

Longterm results of ultrasonic irradiation in Meniere's disease.

Thirty-seven patients with Ménière's disease were treated with ultrasonic irradiation to the lateral and superior semicircular canals. In a longterm follow-up study, lasting alleviation of the vertiginous attacks was found in 24 out of 33 patients (72%). In most of the cases, hearing remained unchanged. It is suggested that the therapeutic effect is associated with a change in the endolymphatic drainage dur to histological alterations in the labyrinth produced by ultrasound.

Adult↗
PubMed1979

The effect of adenoidectomy on secretory otitis media in children.

139 patients, 80 boys and 59 girls aged 1 1/4--13 1/2 years suffering from serous otitis media based on otoscopy and tympanometry had adenoidectomy performed and no other surgical measures taken. The efficiency of the treatment was assessed 2--4 months later. Intially flat tympanometry curves were found in 155 ears, negative middle ear pressure in 70 ears and low curves in 20 ears. 78% of all ears and 73% of the ears with flat curves were seen to normalize during the observation periods.

Acoustic Impedance Tests↗
PubMedDate not supplied

The effect of ultrasound on Meniere's disease.

Among 22 patients with Meniere's disease treated with ultrasonic irradiation, only eight showed extinguished caloric reaction. Long-term therapeutic effect had been obtained in all the patients, Histological examination of the lateral semicircular canal and the crista ampullaris from five patients previously treated with ultrasound for Meniere's disease showed the following changes: (1) In the subepithelial tissue in crista ampullairs no signs of degeneration were found. The nerve fibres were normal. (2) The sensory cells with nerve-endings and supporting cells also appeared normal. (3) The secretory cells showed pronounced cellular vacuolization and increased intercellular space. (4) The lateral semicircular canal was completely obliterated with destruction of the membranous canal. It is concluded that the therapeutic effect may be due to the creation of an endolymphatic fistula.

Adult↗