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K Sørensen

Publications and source records attributed to K Sørensen.

At least 19 recordsLinked to original sources
PubMed2006

Comparative evaluation of six ELISAs for the detection of antibodies to the non-structural proteins of foot-and-mouth disease virus.

To validate the use of serology in substantiating freedom from infection after foot-and-mouth disease (FMD) outbreaks have been controlled by measures that include vaccination, 3551 sera were tested with six assays that detect antibodies to the non-structural proteins of FMD virus. The sera came from naïve, vaccinated, infected and vaccinated-and-infected animals; two-thirds from cattle, the remainder from sheep and pigs. The assays were covariant for sensitivity, but not necessarily for specificity. A commercial kit from Cedi-diagnostics and an in-house assay from IZS-Brescia were comparable to the NCPanaftosa-screening index method described in the Diagnostic Manual of the World Animal Health Organisation. Using these three tests the specificity and sensitivity for the detection of carriers in vaccinated cattle approaches or exceeds 99% and 90%, respectively.

Animals↗
PubMed2003

Effects of exercise and respiration on blood flow in total cavopulmonary connection: a real-time magnetic resonance flow study.

BACKGROUND: Little is known about blood flow and its relationship to respiration during exercise in patients with total cavopulmonary connection (TCPC). METHODS AND RESULTS: We studied 11 patients 12.4+/-4.6 years (mean+/-SD) of age 5.9+/-2.8 years (mean+/-SD) after TCPC operation. Real-time MRI was used to measure blood flow in the superior vena cava (SVC), inferior vena cava (IVC), and ascending aorta under inspiration and expiration during supine lower-limb exercise (rest, 0.5 and 1.0 W/kg) on an ergometer bicycle. IVC and aortic flow increased from 1.60+/-0.52 and 2.99+/-0.83 L/min per m2 at rest to 2.58+/-0.71 and 3.97+/-1.20 L/min per m2 at 0.5 W/kg and to 3.25+/-1.23 and 4.62+/-1.49 L/min per m2 at 1.0 W/kg (P< or =0.05). SVC flow remained unchanged. Resting flow in the IVC was greater during inspiration (2.99+/-1.25 L/min per m2) than during expiration (0.83+/-0.44 L/min per m2) (inspiratory/mean flow ratio, 1.9+/-0.5), and retrograde flow was present during expiration (11+/-12% of mean flow). The predominance of inspiratory flow in IVC diminished with exercise to an inspiratory/mean flow ratio of 1.5+/-0.2 (P< or =0.05) and 1.4+/-0.3 at 0.5 and 1.0 W/kg, respectively. CONCLUSIONS: In the TCPC, circulation IVC and aortic but not SVC flows increase with supine leg exercise. Inspiration facilitates IVC flow at rest but less so during exercise, when the peripheral pump seems to be more important.

Aorta↗
PubMed2001

Peripheral flow response to transient arterial forearm occlusion does not reflect myocardial perfusion reserve.

BACKGROUND: Ultrasonographic evaluation of systemic arterial function is widely available, and a close relation of endothelial function in the coronary and brachial arteries has been documented. It is unknown, however, whether a similar correlation exists for their 2 microcirculatory territories and thus whether assessment of the systemic microcirculation can be used similarly as a surrogate marker of myocardial perfusion. METHODS AND RESULTS: Twenty-three patients with documented coronary artery disease (CAD; 66+/-9 years old, 18 men), 16 patients with syndrome X (SX; 56+/-5 years old, 13 women), and 45 healthy control subjects (C; 34+/-9 years old, 22 men) were studied. Myocardial perfusion was measured at rest and after dipyridamole (0.56 mg. kg(-1). min(-1) over 4 minutes) by PET, and brachial artery blood flow was measured at rest and after transient forearm ischemia by standard Doppler ultrasound techniques. Dipyridamole increased myocardial perfusion in all groups (mL. g(-1). min(-1): CAD, 0.89+/-0.27 versus 1.62+/-0.67, P:<0.001; SX, 0.82+/-0.16 versus 1.67+/-0.49, P:<0.001; and C, 0.82+/-0.15 versus 2.32+/-0.64, P:<0.001). Postocclusion forearm flow increased similarly in all groups (CAD, 52+/-18 versus 174+/-77 mL/min, P:<0.001; SX, 49+/-29 versus 202+/-82 mL/min, P:<0.001; and C, 61+/-34 versus 229+/-108 mL/min, P:<0.001). No significant correlations were found between peripheral and myocardial microcirculatory beds for either resting flow, hyperemic flow, or flow reserve in any of the groups (r(2)<0.1, P:=NS). CONCLUSIONS: The peripheral perfusion responses to transient forearm ischemia do not correlate with dipyridamole-induced myocardial hyperemia. The lack of correlation indicates different mechanisms of microvascular activation or regulation and confirms that extrapolations between findings in the 2 vascular beds are not suitable.

Adult↗
PubMed2001

Spontaneous nisin-resistant Listeria monocytogenes mutants with increased expression of a putative penicillin-binding protein and their sensitivity to various antibiotics.

A concern regarding the use of bacteriocins, as for example the lantibiotic nisin, for biopreservation of certain food products is the possibility of resistance development and potential cross-resistance to antibiotics in the target organism. The genetic basis for nisin resistance development is as yet unknown. We analyzed changes in gene expression following nisin resistance development in Listeria monocytogenes 412 by restriction fragment differential display. The mutant had increased expression of a protein with strong homology to the glycosyltransferase domain of high-molecular-weight penicillin-binding proteins (PBPs), a histidine protein kinase, a protein of unknown function, and ClpB (putative functions from homology). The three former proteins had increased expression in a total of six out of 10 independent mutants originating from five different wild-type strains, indicating a prevalent nisin resistance mechanism under the employed isolation conditions. Increased expression of the putative PBP may affect the cell wall composition and thereby alter the sensitivity to cell wall-targeting compounds. The mutants had an isolate-specific increase in sensitivity to different beta-lactams and a slight decrease in sensitivity to another lantibiotic, mersacidin. A model incorporating these observations is proposed based on current knowledge of nisin's mode of action.

Anti-Bacterial Agents↗
PubMed2001

Reduced intracellular survival of Helicobacter pylori vacA mutants in comparison with their wild-types indicates the role of VacA in pathogenesis.

The vacuolating cytotoxin VacA of Helicobacter pylori plays an important but yet unknown role in pathogenesis. We studied the impact of the vacuolating cytotoxin on H. pylori invasion of and survival within AGS cells (human gastric cell line derived from an antral adenocarcinoma). Isogenic vacA and cagA mutants were constructed in a wild-type clinical isolate H. pylori, AF4. An H. pylori VacA-deficient mutant, AF4(vacA::kan), was cultured in significantly lower numbers from AGS cells after 24 h incubation with gentamicin added to the culture medium than were the type I wild-type strain AF4 (P<0.03) and an isogenic cagA mutant (P<0.01). Complementation of the AF4 vacA mutant with broth culture supernatant from wild-type AF4 improved the intracellular survival of the vacA mutant. We conclude that H. pylori's vacuolating cytotoxin improves the intracellular survival of H. pylori within AGS cells, suggesting the role of the vacuolating cytotoxin in H. pylori pathogenesis.

Anti-Bacterial Agents↗
PubMed2001

Specific endocytosis and catabolism in the scavenger endothelial cells of cod (Gadus morhua L.) generate high-energy metabolites.

The catabolic fate of circulating hyaluronan and the proteoglycan chondroitin sulphate (CSPG) was studied in the Atlantic cod (Gadus morhua L.). Distribution studies using radio-iodinated ligand demonstrated that CSPG was rapidly eliminated from the blood by the endocardial endothelial cells (EECs) of the heart atrium and ventricle. The presence of excess amounts of hyaluronan or CSPG inhibited uptake of [125I]hyaluronan into cultured atrial EECs (aEECs) by 46% and 84%, respectively. Neither formaldehyde-treated serum albumin (FSA) nor mannose inhibited this uptake. The presence of excess amounts of CSPG and hyaluronan inhibited uptake of [125I]CSPG by 90% and 42%, respectively, suggesting that aEECs express a specific hyaluronan binding site that also recognizes CSPG. FSA inhibited endocytosis of [1251]CSPG by 65%, indicating that CSPG is also recognized by the scavenger receptor. Approximately 17% and 57% of added [125I]hyaluronan and 15% and 65% of the added [125I]CSPG were endocytosed after 1 and 24h, respectively. High-performance liquid chromatographic analyses of the spent medium after endocytosis of hyaluronan and CSPG serglycin labelled biosynthetically with 3H in the acetyl groups identified labelled the low-molecular-mass degradation products as [3H]acetate, indicating that aEECs operate anaerobically. These findings suggest that acetate released from cod EECs following catabolism of endocytosed hyaluronan and CSPG represents a high-energy metabolite that may fuel cardiomyocytes.

Animals↗
PubMed2001

Histochemical tracing of bismuth in Helicobacter pylori after in vitro exposure to bismuth citrate.

BACKGROUND: Bismuth-containing drugs are widely used in the treatment of Helicobacter pylori associated peptic ulcer. The mechanism of action of bismuth salts is, however, not fully understood, and at present no histochemical techniques for the demonstration of bismuth in H. pylori are available. The aims were to present a histochemical method for the detection of bismuth in H. pylori and to demonstrate bismuth uptake in H. pylori after in vitro exposure to bismuth citrate. METHODS: H. pylori cultures (the strain used in this study was CCUG 17874), were exposed to bismuth citrate at different concentrations (0, 4.6, 80, 200 microM) and for different lengths of time (0 min, 15 min, 1 h, 24 h, 48 h). The samples were fixed in glutaraldehyde, centrifuged, and exposed to autometallographic (AMG) development in order to detect bismuth histochemically. RESULTS: A detailed protocol on the AMG bismuth technique on H. pylori exposed to bismuth in vitro is given. This method results in easily detectable AMG grains of silver enhanced bismuth particles at the electron microscopical level, and shows that bismuth accumulates in H. pylori, predominantly near the wall of the bacteria. Bismuth uptake is followed by bacterial degeneration. CONCLUSION: The present technique with its ability to trace bismuth constitutes a valuable tool in the efforts of clarifying the mechanism of action of bismuth on H. pylori, and supports the notion that bismuth has an antimicrobial activity in itself.

Anti-Ulcer Agents↗
PubMed2000

rpoS gene function is a disadvantage for Escherichia coli BJ4 during competitive colonization of the mouse large intestine.

The ability of Escherichia coli to survive stress during growth in different environments is, in large part, dependent on rpoS and the genes that comprise the rpoS regulon. E. coli BJ4 and an isogenic BJ4 rpoS mutant were used to examine the influence of the rpoS gene on E. coli colonization of the streptomycin-treated mouse large intestine. Colonization experiments in which the wild-type E. coli BJ4 and its rpoS mutant were fed individually as well as simultaneously to mice suggested that E. coli BJ4 does not face prolonged periods of nutrient starvation in the mouse large intestine and that the rpoS regulon is not expressed during long-term colonization after adaptation of the bacteria to the gut environment.

Animals↗
PubMed1999

Level and distribution of progesterone in bovine milk in relation to storage in the mammary gland.

The study investigated the effect of the place of storage of milk in the mammary gland on progesterone concentrations in whole milk, skim milk and milk fat. Skim milk, milk fat and whole milk progesterone concentrations were lower (P < 0.05) in milk fractions obtained from the cisternal part of the mammary gland compared to those in the milk fractions from the alveoli. Mean milk fat concentrations did not mirror the changes in the mean skim milk, milk fat and whole milk progesterone concentrations. After administration of oxytocin, milk fat concentrations rose significantly (P < 0.01). At the same time, skim milk and milk fat progesterone concentrations remained unchanged (P > 0.05), compared to those in the milk fractions of alveolar origin, obtained before oxytocin administration. Skim milk and whole milk progesterone concentrations were higher (P < 0.01) in composite milk and in milk samples collected 1 h after milking, compared to concentrations in the milk samples collected before morning milking and at 3, 5, 7 and 9 h after milking. The results suggest that defatted milk, milk fat and whole milk progesterone concentrations were affected by the place of storage of the milk in the mammary gland, and that this effect is independent of milk fat content. Time of milk sampling, not the milk fat concentration, in relation to time of milking, was a critical factor in determining skim milk, milk fat and whole milk progesterone. The study also revealed that the concentrations of the other milk components, somatic cell count, lactose and protein were affected by the place of storage of milk in the mammary gland.

Animals↗
PubMed1999

Clinical assessment of indication for ACE-inhibitor treatment early after acute myocardial infarction.

An investigation was conducted to assess whether an algorithm based on simple clinical information would suffice to classify patients with acute myocardial infarction, with respect to indication for angiotensin-converting-enzyme inhibitor treatment. One hundred consecutive patients with myocardial infarction were prospectively studied. Based on clinical, radiological, electrocardiographic and biochemical information, the patients were classified as having (a) significantly depressed left ventricular function (ejection fraction < or = 40%) justifying treatment with angiotensin-converting-enzyme inhibitors (ACEI), (b) preserved ventricular function (ejection fraction > 40%) making ACEI unnecessary, or (c) indeterminate ventricular function, requiring further examination. Using a blinded design, ejection fraction was determined by echocardiography and radionuclide ventriculography. A clinical assumption of reduced left ventricular function had a predictive value of an echocardiographically determined ejection fraction < or = 40% of 83% (n = 23). Clinical criteria of good ventricular function had a predictive value of ejection fraction > 40% of 96% (n = 24). In these two groups clinical misclassification occurred in five patients with ejection fraction within the range of 39-45%. Left ventricular function was found to be clinically indeterminate in 53 of the 100 patients. Ejection fraction values assessed by radionuclide ventriculography (n = 44) were on average 9.3%-points lower than echocardiographic values. The indication for ACEI can apparently be determined on the basis of readily available clinical information in approximately 50% of patients with acute myocardial infarction.

Adult↗
PubMed1999

Wrist and finger joint MR imaging in rheumatoid arthritis.

PURPOSE: To elaborate the best MR imaging protocol for studies in rheumatoid arthritis (RA) and to evaluate the sensitivity and interobserver agreement with respect to detection of bone erosions (MR and radiography) and grading of synovial membrane hypertrophy (MR imaging only). MATERIAL AND METHODS: MR imaging and conventional radiography of wrist and metacarpophalangeal (MCP) joints were performed in 41 RA patients and 3 healthy controls. The following pulse sequences were applied: T1-weighted spin-echo (T1-SE) with and without contrast enhancement, T2-SE, T2-turbo-SE, T1-2D-FLASH, T1-3D-FLASH, fat-saturated-T1-SE, STIR and 3D-DESS. RESULTS: Bone erosions were found by MR compared to radiography in 261 versus 85 bones of the wrist (ratio 3.1) and 59 versus 21 MCP joint quadrants (ratio 2.81). MR and radiography interobserver agreements were both approximately 90%. Likewise, MR scored synovial membrane hypertrophy in wrist and MCP joints with a high interobserver agreement. The most informative MR sequence appeared to be contrast-enhanced T1-SE MR, preferably with fat saturation. A STIR sequence or T2-weighted fat saturation sequence was useful in screening for joint disease. CONCLUSION: The sensitivity of MR is superior to conventional radiography with respect to detection of bone erosions in wrist and MCP joints. The interobserver agreement for MR and radiography was similar. Thus, MR of wrist and finger joints may become a useful supplement to conventional radiography in the evaluation of RA patients in clinical trials and clinical practice.

Adult↗
PubMed1998

Mimicry profiles are affected by human-induced habitat changes.

Mimicry theory predicts that mimics in a Batesian mimicry complex evolve to resemble models closely, and that there is a limit on the numbers of mimics relative to models. For hoverflies (Diptera: Syrphidae), supposed mimics of social wasps (Hymenoptera: Vespidae, neither of these is true; many mimics are imperfect and in the UK and Europe they outnumber their models manifold. We hypothesized that the high abundance of mimics relative to models in the UK may be the result not just of mimic model dynamics, but of habitat changes caused by humans. Most of the larvae of poor mimics are aphidophagous, and changes from ancient forest to agricultural and/or urban habitats may have vastly augmented aphid numbers. Using new and literature data, we compared mimicry profiles of habitats differing in their degree of habitat disturbance. In both cases more highly disturbed habitats had proportionally more poor mimics and fewer high-fidelity mimics than less disturbed habitats. This supports the hypothesis that habitat change has an effect on model to mimic ratios.

Adaptation, Biological↗
PubMed1997

[Violence 1994--Oslo Legevakt].

2,545 patients were treated in Oslo Legevakt for injuries caused by violence in 1994. Additionally 37 patients were admitted directly to hospital by ambulance. Half of the cases were young men who were injured in public places or in the street. 64% were under the influence of alcohol during the episode. Patients from central, eastern parts of Oslo were overrepresented, and patients with a foreign cultural background were more frequently exposed to violence than Norwegians were. Weapons were used in 25% of the cases. 131 patients were taken to hospital, and 127 patients were retained for observation throughout the night at Oslo Legevakt. Despite the presence of many serious injuries, most of the patients suffered minor physical injuries. In half of all the cases the treatment was completed at the first consultation. Compared with other investigations on violence, we found no certain indication that the amount of patients needing treatment for injuries caused by violence in Oslo has increased dramatically during the last decades. Ordinary people's fear of aggression and violence in Oslo today is perhaps exaggerated?

Adolescent↗
PubMed1997

Progress of emphysema in severe alpha 1-antitrypsin deficiency as assessed by annual CT.

PURPOSE: To assess serial CT as a measure of the progress of emphysema in patients with severe alpha 1-antitrypsin deficiency (phenotype PiZ). MATERIAL AND METHODS: In a randomized placebo-controlled study of alpha 1-antitrypsin augmentation therapy, 22 patients with moderate emphysema were followed for 2-4 years with an annual lung CT. The images were analysed by means of semiautomatic lung detection, and the degree of emphysema was quantitated by the density-mask and the percentile methods. The influence of lung volume was standardised by a regression model. RESULTS: A highly significant decline in Hounsfield units (HU) was found in low-density areas, corresponding to a mean (SE) annual loss of lung tissue of 2.1 (0.4) g/l lung volume. Analysis of a single slice at 5 cm below the level of the carina gave comparable results: 2.4 (0.4) g/l. CONCLUSION: Serial CT is a sensitive measure of the progress of emphysema in patients with severe alpha 1-antitrypsin deficiency.

Acute Disease↗
PubMed1996

[CT scanning in suspected ileus or pneumoperitoneum].

In this prospective survey of six months duration, 66 consecutive patients referred for plain abdominal views on suspicion of bowel obstruction or pneumoperitoneum had supplementary abdominal CT-scans performed. Thirty-one patients underwent surgery. Seventeen suffered from bowel obstruction, one patient had both bowel obstruction and pneumoperitoneum and three had pneumoperitoneum. CT-scans correctly demonstrated all cases of bowel obstruction or pneumoperitoneum. The plain abdominal views resulted in one false negative diagnosis of bowel obstruction and one false negative diagnosis of pneumoperitoneum. Ten of the operated patients had neither bowel obstruction nor pneumoperitoneum. In nine of these cases this was in accordance with the interpretation of both CT and plain abdominal views. Both modalities resulted in one false positive diagnosis of bowel obstruction. In most cases we find no difference between the two modalities in demonstrating or excluding bowel obstruction or pneumoperitoneum. We therefore conclude that the plain abdominal X-ray should be the primary examination on suspicion of bowel obstruction or pneumoperitoneum. We recommend CT-scanning in cases with clinical suspicion of bowel obstruction or pneumoperitoneum and no obvious pathology on the plain abdominal X-ray.

Adult↗
PubMed1996

Changes in synovial membrane and joint effusion volumes after intraarticular methylprednisolone. Quantitative assessment of inflammatory and destructive changes in arthritis by MRI.

OBJECTIVE: To evaluate synovial membrane volumes, effusion volumes, and cartilage and bone erosion scores determined by magnetic resonance imaging (MRI) as markers of disease activity and severity in arthritis. METHODS: Gadolinium-DTPA enhanced MRI of 18 arthritic knees was performed before and 1, 7, 30 and 180 days after intraarticular methylprednisolone injection until clinical relapse. Intraobserver, interobserver, and inter-MRI variations were determined from 2 successive MRI of another 6 knees. RESULTS: In all knees synovial membrane and effusion volumes decreased within the first posttreatment week (median decrease 49 and 65%, respectively), and remained low during remission. Synovial volumes, but not effusion volumes, increased to pretreatment levels in case of clinical relapse, indicating that synovial volumes were most important to the clinical appearance. The intraobserver + interobserver + inter-MRI variation was maximally 26%. Total volumes and volumes in a selected sagittal slice were highly statistically correlated. The duration of clinical remission in patients with rheumatoid arthritis (RA) was significantly inversely correlated to the pretreatment synovial volume (both total and "one slice" volumes), but not to the effusion volume, MRI or radiography scores of erosions or any clinical/laboratory variables. Cartilage and bone erosions, invisible by radiography, were visualized by MRI. No progressive erosive changes were observed. CONCLUSION: MRI-determined synovial and effusion volumes and MRI scores of cartilage and bone erosions are reproducible and may be sensitive measures of disease activity and severity in RA. The synovial volume may rather than the effusion volume determine clinical appearance. Both are influenced by the present inflammatory activity. The pretreatment synovial volume may have predictive value to treatment outcome in RA.

Adult↗