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O Hansen

Publications and source records attributed to O Hansen.

At least 37 records · Page 2Linked to original sources
PubMed2001

Polarization measurements in high-energy deuteron photodisintegration.

We present measurements of the recoil proton polarization for the d(gamma-->,p-->)n reaction at straight theta(c.m.) = 90 degrees for photon energies up to 2.4 GeV. These are the first data in this reaction for polarization transfer with circularly polarized photons. The induced polarization p(y) vanishes above 1 GeV, contrary to meson-baryon model expectations, in which resonances lead to large polarizations. However, the polarization transfer Cx does not vanish above 1 GeV, inconsistent with hadron helicity conservation. Thus, we show that the scaling behavior observed in the d(gamma,p)n cross sections is not a result of perturbative QCD. These data should provide important tests of new nonperturbative calculations in the intermediate energy regime.

Journal Article↗
PubMed2001

Comparative study on the effects of three insecticides (fipronil, imidacloprid, selamectin) on developmental stages of the cat flea (Ctenocephalides felis Bouché 1835): a light and electron microscopic analysis of in vivo and in vitro experiments.

The effects of three insecticides (fipronil, imidacloprid and selamectin) on developmental stages of cat fleas (Ctenocephalides felis) were studied in vivo, in vitro and by means of light and electron microscopy. The results were documented by video. Adult fleas were attached to the skin of dogs that had been treated 7 days before with one of the three compounds. Furthermore, adult fleas were exposed exclusively to the hair and skin debris of such treated dogs or were placed on filter papers that had been impregnated with one of these three compounds or with the blood of treated dogs. Larval fleas were exposed to hair of treated dogs, to debris obtained by combing treated dogs, to dried blood samples of treated dogs or were placed onto filter papers impregnated with one of the three compounds. In these experiments with adult and larval fleas, it was noted that none of the three insecticides had a repellent effect on adult or larval fleas. Imidacloprid was the only compound that acted exclusively by body contact, and was apparently taken up by adult and larval fleas via the thin, non-sclerotized intersegmental membranes of the flea's body, shown when flea stages were exposed to hairs taken from dogs treated with one of the compounds or placed onto drug-impregnated filter papers. Imidacloprid killed larvae and adult fleas within 1 h, while it took at least 24 h until all adult fleas had died on fipronil- or selamectin-treated dogs, thus allowing longer feeding periods, increasing the risk of transmission of flea-derived diseases. Flea larvae covered with debris from dogs topically treated 7 days before with fipronil, imidacloprid or selamectin died, like the untreated control, within 16-28 h after exposure. This was, however, probably mainly due to a drying effect. Adult and larval fleas exposed to filter papers impregnated with the blood of treated dogs survived longer than 7 days, as did the untreated controls. All three drugs apparently acted on nerves and muscles and thus stopped motility.

Animals↗
PubMed2001

In vivo and in vitro effects of imidacloprid on sheep keds (Melophagus ovinus): a light and electron microscopic study.

The effects of imidacloprid (Advantage) on sheep keds (Melophagus ovinus Linne 1758) were studied in vivo and in vitro by means of direct observation (monitored on video tape) and by light and electron microscopy. It was found that: 1. Imidacloprid acted rapidly on all motile stages of the sheep keds. Within 3-4 min after exposure they became immobile and their legs and the abdomen started tetanic trembling movements for 15-30 min, leading to death. 2. The compound is apparently taken up by the body, since it also acted on those sheep keds that had been exclusively exposed to imidacloprid-contaminated filter papers. 3. The compound is available and active for more than 1 month in the wool of sheep; even rainfall does not reduce its efficacy. Body contact between treated mother sheep and their lambs protects them from infestation with these ectoparasites. 4. The compound initiates an ultimately lethal destruction of the ganglia, nerve chords and related muscle fibers, as can be seen in electron micrographs.

Administration, Topical↗
PubMed2001

The alpha1 isoform of Na+,K+-ATPase in rat soleus and extensor digitorum longus.

A novel immunochemical method was used for determination of the concentration of Na,K-adenosine triphosphatase (ATPase) containing the ouabain-insensitive alpha1 peptide in rat m. soleus and extensor digitorum longus (EDL). Homogenates of soleus and EDL from 4-week or 10-11-week rats were run on sodium dodecyl sulphate (SDS) gels and in parallel lanes was run a well-characterized preparation of Na,K-ATPase isolated from rat kidney that is known to contain only the alpha1 isoform. After electroblotting to PVDF membranes blots were incubated with the alpha1 specific monoclonal antibody 3B, then with an 125I-coupled secondary antibody, and finally the specific labelling of adjacent alpha spots was analysed by means of an electronic autoradiography system (Packard InstantImager). As the alpha1 content of reference Na,K-ATPase was known from the specific Na+-dependent 32P-phosphorylation capacity, the alpha1 content of adjacent alpha spots in homogenates from soleus and EDL could be calculated. In soleus and EDL from 4-week rats an alpha1 concentration of 135-220 pmol (g tissue)(-1) was found, dependent on the conditions of the experiments but without significant differences between the two types of muscle. In 10-11-week rats a significantly lower concentration of 70-80 and 40-60 pmol (g tissue)(-1) in soleus and EDL, respectively, was found. Ouabain-insensitive Na,K-ATPase containing the alpha1 peptide may thus represent 15-25% of the total number of pumps in skeletal muscle if another 20-30% has to be added to the pool known from (3H)ouabain binding.

Animals↗
PubMed2001

Geographical pattern of female deaths from myocardial infarction in an urban population: fatal outcome out-of-hospital related to socio-economic deprivation.

OBJECTIVE: This study of myocardial infarction (MI) amongst urban women has sought to assess whether there are differences in fatal outcome, in-hospital respectively out-of-hospital, between residential areas defined in terms of socio-economic circumstances. DESIGN: Register-based surveillance study 1986-95. SETTING: Seventeen residential areas in the city of Malmö, Sweden. SUBJECTS: Women 20-74 years of age. MAIN OUTCOME MEASURES: Differences in fatal outcome, in-hospital respectively out-of-hospital, between residential areas were expressed in terms of age-adjusted odds ratios (ORs), calculated by means of logistic regression. Socio-economic circumstances in the areas were expressed in terms of a composite score. RESULTS: Between residential areas there were marked and statistically significant differences in incidence (range 124-328/10(5), P < 0.001, d.f.=16) and mortality (range 38-132/10(5), P < 0.005, d.f.=16). Area rates of mortality covaried with incidence (r=0.85, P < 0.001) and with odds ratios of fatal outcome out-of-hospital (r=0.52, P=0.031) but not in-hospital. The odds ratios of fatal outcome out-of-hospital decreased in a statistically significant stepwise fashion from areas in the lowest socio-economic quintile (reference) to areas in the highest socio-economic quintile (OR: 0.67, 95% CI: 0.48-0.94). There was no corresponding association with the odds ratios of fatal outcome in-hospital. CONCLUSIONS: The high rate of mortality from MI amongst women in areas with deprived socio-economic circumstances was related to deaths occurring out-of-hospital. In order to assess the preventive potential there is a need for further studies that may clarify to what extent the association with socio-economic circumstances can be explained by other factors and conditions known to influence the probability of survival.

Adult↗
PubMed2001

Ischaemic jejunal stenosis complicating portal and mesenteric vein thrombosis: a report of two cases.

A major complication of portal and mesenteric vein thrombosis is acute bowel ischaemia resulting in infarction and requiring immediate resection of the involved segment. Sufficient collaterals can prevent acute haemorrhagic infarction, but bowel stenosis due to chronic ischaemia may develop. We report two cases of ischaemic jejunal stenosis occurring 4 weeks after successful treatment of portal and mesenteric vein thrombosis. Diagnosis of high-grade segmental stenosis of the jejunum was established by contrast medium radiography of the gastrointestinal tract. After laparotomy and resection of the stenosed jejunal segment, both patients recovered well from the operation and were released from hospital. Follow-up examinations revealed an unremarkable state of health. Ischaemic bowel stenosis should be considered in patients with recurring abdominal pain after mesenteric and portal vein thrombosis. A close follow-up of every patient after treatment for mesenteric and portal vein thrombosis should be carried out to ensure early diagnosis of this complication.

Adult↗
PubMed2001

Electrolyte composition of mink (Mustela vison) erythrocytes and active cation transporters of the cell membrane.

Red blood cells from mink (Mustela vison) were characterized with respect to their electrolyte content and their cell membranes with respect to enzymatic activity for cation transport. The intra- and extracellular concentrations of Na+, K+, Cl-, Ca2+ and Mg2+ were determined in erythrocytes and plasma, respectively. Plasma and red cell water content was determined, and molal electrolyte concentrations were calculated. Red cells from male adult mink appeared to be of the low-K+, high-Na+ type as seen in other carnivorous species. The intracellular K+ concentration is slightly higher than the extracellular one and the plasma-to-cell chemical gradient for Na+ is weak, though even the molal concentrations may differ significantly. Consistent with the high intracellular Na+ and low K+ concentrations, a very low or no ouabain-sensitive Na+, K(+)-ATPase activity and no K(+)-activated pNPPase activity were found in the plasma membrane fraction from red cells. The Cl- and Mg2+ concentrations expressed per liter cell water were significantly higher in red cells than in plasma whereas the opposite was the case with Ca2+. The distribution of Cl- thus does not seem compatible with an inside-negative membrane potential in mink erythrocytes. In spite of a steep calcium gradient across the red cell membrane, neither a calmodulin-activated Ca(2+)-ATPase activity nor an ATP-activated Ca(2+)-pNPPase activity were detectable in the plasma membrane fraction. The origin of a supposed primary Ca2+ gradient for sustaining of osmotic balance thus seems uncertain.

Animals↗
PubMed2000

Antideuteron production in 158A GeV/c Pb + Pb collisions

The invariant cross section as a function of transverse momentum for antideuterons produced in 158A GeV/c per nucleon Pb+Pb central collisions has been measured by the NA44 experiment at CERN. This measurement, together with a measurement of antiprotons, allows for the determination of the antideuteron coalescence parameter. The extracted coalescence radius is found to agree with the deuteron coalescence radius and radii determined from two particle correlations.

Journal Article↗
PubMed2000

[Duodenal diverticulum--an unusual manifestation of recurrent retroperitoneal liposarcoma].

The treatment of choice in retroperitoneal liposarcoma is curative R0 resection. However, there are high rates of reoperation due to recurrence. Our present case report shows difficulties in detecting recurrence due to atypical configuration. Eventually a huge diverticulum of the duodenum combined with leiomyoma in its neck area was histopathologically identified as a recurrent liposarcoma.

Aged↗
PubMed2000

Environmental sensors based on micromachined cantilevers with integrated read-out

An AFM probe with integrated piezoresistive read-out has been developed and applied as a cantilever-based environmental sensor. The probe has a built-in reference cantilever, which makes it possible to subtract background drift directly in the measurement. Moreover, the integrated read-out facilitates measurements in liquid. The probe has been successfully implemented in gaseous as well as in liquid experiments. For example, the probe has been used as an accurate and minute thermal sensor and as a humidity sensor. In liquid, the probe has been used to detect the presence of alcohol in water.

Journal Article↗
PubMed2000

Distribution and determinants of ischaemic heart disease in an urban population. A study from the myocardial infarction register in Malmö, Sweden.

OBJECTIVE: Age adjusted incidence of myocardial infarction has been found to vary substantially between the residential areas of the city of Malmö. The objective of this study was to assess the extent to which major biological risk factors and socio-economic circumstances account for the differences in incidence of and mortality from myocardial infarction. DESIGN: Ecological study of risk factor prevalence and incidence and mortality from myocardial infarction. SETTING: Seventeen administrative areas in Malmö, Sweden. SUBJECTS: Assessment of risk factor prevalence was based on 28 466 men and women, ranging from 45 to 73 years old, who were recruited as participants in the Malmö Diet and Cancer study. Information on serum lipids was available in a random subsample of 5362 subjects. Information about socio-economic level of the residential area was based on statistics from the Malmö City Council and Statistics Sweden. MAIN OUTCOME MEASURES: Weighted least square regressions between prevalence of risk factors (i.e. smoking, hypertension, obesity, diabetes, hypercholesterolemia and hypertriglyceridemia), a myocardial infarction risk score, a socio-economic score and incidence and mortality from myocardial infarction. RESULTS: The risk factor prevalence and myocardial infarction incidence was highest in areas with low socio-economic level. Prevalence of smoking, obesity and hypertension was significantly associated with myocardial infarction incidence and mortality rates amongst men (all r > 0.60). Prevalence of smoking was significantly associated with incidence and mortality from myocardial infarction amongst women (r = 0.66 and r = 0.61, respectively). A myocardial infarction risk score based on four biological risk factors explained 40-60% of the intra-urban geographical variation in myocardial infarction incidence and mortality. The socio-economic score added a further 2-16% to the explained variance. CONCLUSION: In an urban population with similar access to medical care, well-known biological cardiovascular risk factors account for a substantial proportion of the intra-urban geographical variation of incidence of and mortality from myocardial infarction. The socio-economic circumstances further contribute to the intra-urban variation in disease.

Aged↗
PubMed2000

Trends in long-term survival after myocardial infarction: less favourable patterns for patients from deprived areas.

OBJECTIVE: New treatments have improved the prognosis for patients with acute myocardial infarction. However, studies on long-term survival are not unequivocally in favour of an improved long-term prognosis. This study aimed to analyse trends in 3-year survival in relation to sex, age and socioeconomic level of residential area. SETTING: The Malmö myocardial infarction register, Sweden. PARTICIPANTS: All men and women in the city who, between 1978 and 1995, were admitted for a first acute myocardial infarction (n = 11 226). MAIN OUTCOME MEASURES: Age-standardized 3-year survival rates. RESULTS: Both 28-day and 3-year survival rates improved markedly during the study period. Age-standardized 3-year survival (per 100 patients) amongst men and women who survived 28 days increased, between 1978-81 and 1991-95, from 64 to 78 in men and from 66 to 77 in women, an annual increase of 1.4% (95% CI = 1.1-1.7) and 1.2% (0.8-1.5), respectively. There were marked differences in survival between residential areas with different socioeconomic circumstances. The 3-year survival rates amongst men correlated significantly with the socioeconomic circumstances in the areas expressed in terms of a socioeconomic score (men: r = 0.60, n = 17, P = 0.01; women: r = 0.37, P = 0.15). Trends tended to be less favourable in deprived areas. CONCLUSION: Three-year survival after first myocardial infarction has continuously improved for men and women in all age groups. Prognosis was worse and trends tended to be less favourable for patients from deprived areas.

Adult↗
PubMed2000

Esthesioneuroblastoma--what is the optimal treatment?

A retrospective review was conducted on 13 patients with esthesioneuroblastoma (ENB), treated at our institution from 1977 to 1997. According to the Kadish classification, one patient was in stage A, 5 patients were classified as stage B and 7 patients were in stage C. Five-year disease-specific survival was found to be 51%. Forty-six percent of the patients experienced relapse and despite intensive salvage therapy, median survival after recurrences was only 12 months. This indicates the need for good primary control in local as well as distant disease. The role of pre- versus postoperative radiotherapy to secure good local control is discussed and compared with the literature, and treatment guidelines are proposed. The tumours were graded according to the Hyams' classification and its importance as a prognostic factor is briefly discussed.

Adolescent↗
PubMed2000

Incidence of myocardial infarction in women. A cohort study of risk factors and modifiers of effect.

STUDY OBJECTIVE: To assess whether the increased incidence of myocardial infarction and death associated with smoking, hypertension, hyperlipidaemia and diabetes varies significantly between groups defined in terms of occupation, education and marital status. SETTING: Malmö, Sweden. PARTICIPANTS: 9351 women, aged 28-55, with a mean follow up of 10.7 years. MAIN RESULTS: Smoking, hypertension (> or = 160/95 mm Hg or treatment), hyperlipidaemia (cholesterol > or = 6.5 mmol/l or triglycerides > or = 2.3 mmol/l), diabetes, low occupation and education levels were significantly more common among women who experienced a fatal or nonfatal myocardial infarction during the follow up (n = 104) than in other women (n = 9247). Exposure to smoking, hypertension and hyperlipidaemia showed substantial differences between groups defined in terms of education, occupation and marital status. The association between low occupation and myocardial infarction remained statistically significant after adjustments for several potential confounders (RR = 2.6, 95% CI 1.1, 6.0). Single women had similarly higher adjusted mortality rates than married women (RR = 1.4, 95% CI 1.1, 1.8). When other major risk factors were taken into account, the relative risk for mortality and myocardial infarction associated with smoking was 2.6 (95% CI 2.0, 3.4) and 7.8 (95% CI 4.4, 13.9), respectively. CONCLUSION: In this urban female population, short education and low occupation level were both associated with an increased prevalence of smoking, hypertension, hyperlipidaemia and diabetes. Low occupation level increases the rate of cardiac events caused by exposure to these four risk factors.

Adult↗
PubMed1999

Heterogeneity of Na+/K+-ATPase from rectal gland of Squalus acanthias is not due to alpha isoform diversity.

Purified Na+/K+-ATPase (EC 3.6.1.37) isolated from the rectal gland of Squalus acanthias was characterized in ouabain-binding studies and with respect to isoform(s) of the alpha peptide. To avoid enzyme inactivation [3H]ouabain equilibrium binding was carried out at 20 degrees C. The heterogeneity of Na+/K+-ATPase isolated from shark rectal gland was similar in [3H]ouabain binding as previously seen in hydrolytic studies. The binding isotherms were compatible with the existence of a high-affinity (Kdis 0.69 nM) and a low-affinity (Kdis 42 nM) component of 1.46 and 0.79 nmol.(mg protein)-1, respectively. In Western blots the alpha peptide of the enzyme hybridized with an isoform-specific polyclonal antibody raised to an alpha3-specific region of the large intracellular domain of rat Na+/K+-ATPase, but not with the supposed alpha3-specific monoclonal antibody MA3-915 with its epitope near the N-terminus. Semi-quantitative analysis of the reaction of the alpha3-specific polyclonal antibody with the alpha peptide from the shark enzyme compared to the reaction with alpha peptide from rat brain enzyme indicated that this region is not exactly the same in the two species. The alpha peptide of shark enzyme was not recognized by alpha1- or alpha2-specific polyclonal antibodies, or by the alpha1-specific monoclonal antibodies 3B and F6. The large intracellular domain of Na+/K+-ATPase from shark rectal gland thus seems to be alpha3-like and no alpha isoform heterogeneity seems able to account for the heterogeneity seen in ouabain binding.

Animals↗
PubMed1999

Effects of imidacloprid on adult and larval stages of the flea Ctenocephalides felis after in vivo and in vitro application: a light- and electron-microscopy study.

The effects of imidacloprid (Advantage) on the larval and adult stages of cat fleas (Ctenocephalides felis) were studied in vivo and in vitro by means of light and electron microscopy. It was found that: 1. The compound acted rapidly on both larval and adult fleas, killing both stages within 20 min of contact. 2. When applied as a spot-on to the skin of dogs, the compound localized in the water-resistant lipid layer of the skin surface and in the hairs but not in the blood. 3. Thus, the compound was not taken up during sucking of the flea but was absorbed via the thin intersegmental membranes, since larval and adult fleas that had only external contact with imidacloprid-impregnated paper or with shaved hairs from imidacloprid-treated dogs showed reactions similar to those shown by fleas sitting on treated skin. 4. The compound led to a continuous blockage of insect-specific nicotinic-acetylcholine receptors (nAChR), causing tetanic muscle cotractions within minutes of exposure. This manifested as intense trembling of the legs and pumping movements of the body. The affected flea stages remained motionless while the nerves and muscles were constantly and irreversibly destroyed due to hyperactivity. The ganglia of the head and thorax and the striated muscles of the flea body and legs were damaged first, whereas the intestinal movements (e.g., visible in larvae) took longer to exhibit damage. In summary, these studies show that imidacloprid kills larval and adult flea stages rapidly via the same mode of action and thus prevents the development of flea populations in human or animal dwellings.

Animals↗
PubMed1999

Long-term continuous 5-fluorouracil infusion in patients with advanced head and neck cancer.

Forty-two patients with advanced head and neck cancer entered this phase II trial of long-term continuous 5-fluorouracil (5-FU) infusion at a dose of 300 mg/m2/day for a maximum of 16 weeks. Objective response rate was 15% in 41 evaluable patients. Median time to progression was 2.9 months, and median survival 4 months. Toxicity was generally mild. Reversible stomatic and hand-foot syndrome WHO grade III-IV was observed in 5 and 3 patients, respectively. Haematologic toxicity and emesis were less pronounced with no grade III-IV toxicity. One patient had to discontinue treatment because of ataxia. No catheter-related toxicity and no treatment-related mortality were observed. In the present study long-term continuous infusion of 5-FU has only modest activity in terms of response rate, but the activity is comparable with other single-agent regimens. The treatment is well tolerated, with minimal toxicity making it usable in a palliative situation.

Adolescent↗