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Biomedical subjects

O Hansen

Publications and source records attributed to O Hansen.

At least 19 recordsLinked to original sources
PubMed2006

Survival rate 28 days after hospital admission with first myocardial infarction. Inverse relationship with socio-economic circumstances.

OBJECTIVE: To study to what extent geographical differences of the mortality from ischaemic heart disease (IHD) can be accounted for by the 28-day case fatality rate (CFR) following first hospital admittance for acute myocardial infarction (MI) and whether the geographical pattern of survival has any relationship with socio-economic circumstances. DESIGN: Register-based surveillance study. SETTING: Seventeen residential areas in Malmö, Sweden. SUBJECTS: All 5533 patients were admitted during 1986-1995 for a first acute MI at Malmö University Hospital. Main outcome measures. CFR is based on record linkage with national registers. Area-specific cardiovascular and socio-economic scores (SES) are based on previous cross-sectional studies. RESULTS: In patients below 75 years of age, differences of the 28-day CFR accounted for 20-30% of the geographical variance in mortality from IHD. No corresponding association was found in older age groups. Patients from areas with low SES had the highest CFR, 23.8%. The odds ratios of fatal outcome for patients from areas with median and low SES (versus high SES) were 1.23 (95% CI: 1.01-1.50) and 1.25 (95% CI: 1.03-1.52), respectively (P for trend: 0.060). The strongest correlation was observed in men below 75 years of age (P for trend: 0.007). During the study period there was an improvement of the survival rate for patients from high and medium SES areas but no corresponding change for patients coming from areas having a low SES. CONCLUSIONS: In patients below 75 years, geographical differences of the mortality from IHD were related to differences of the 28-day CFR following hospital admittance for a first MI. Rates of survival were inversely related to socio-economic circumstances in the patient's residential area.

Age Factors↗
PubMed2005

Cell volume increase in murine MC3T3-E1 pre-osteoblasts attaching onto biocompatible tantalum observed by magnetic AC mode atomic force microscopy.

Magnetic AC mode (MACmode) atomic force microscopy (AFM) was used to study murine (mouse) MC3T3-E1 preosteoblastic cells attached to biocompatible tantalum substrates. Cell volumes of attached cells derived from AFM images were compared to volumes of detached cells in suspension measured by the Coulter sizing technique. An increase of approximately 50% in cell volume was observed when the cells attached to planar tantalum substrates and developed a flattened structure including lamellipodia. We address thoroughly the issues general to the AFM determination of absolute cell volumes, and compare our magnetic AC mode AFM measurements to hitherto reported cell volume determinations by contact mode AFM.

Animals↗
PubMed2005

Charged meson rapidity distributions in central Au+Au collisions at square root(sNN) = 200 GeV.

We have measured rapidity densities dN/dy of pi+/- and K+/- over a broad rapidity range (-0.1 < y < 3.5) for central Au + Au collisions at square root(sNN) = 200 GeV. These data have significant implications for the chemistry and dynamics of the dense system that is initially created in the collisions. The full phase-space yields are 1660 +/- 15 +/- 133 (pi+), 1683 +/- 16 +/- 135 (pi-), 286 +/- 5 +/- 23 (K+), and 242 +/- 4 +/- 19 (K-). The systematics of the strange to nonstrange meson ratios are found to track the variation of the baryochemical potential with rapidity and energy. Landau-Carruthers hydrodynamics is found to describe the bulk transport of the pions in the longitudinal direction.

Journal Article↗
PubMed2004

Phase II trial of oral vinorelbine in combination with cisplatin followed by consolidation therapy with oral vinorelbine in advanced NSCLC.

BACKGROUND: Among the cytotoxic agents commonly combined with cisplatin in the treatment of advanced NSCLC, vinorelbine has led to significant outcome improvements. Adding more than four cycles of the combination regimen increase toxicities. The availability of an oral form of vinorelbine appeared as a particularly convenient way to provide a consolidation treatment to patients who have achieved an objective response or stable disease. PATIENTS AND METHODS: This multi-centre phase II open-label, non-comparative study was designed to evaluate the treatment with four cycles of the combination chemotherapy with oral vinorelbine at the dose of 60 mg/m2 on day 1 and day 8 for the first cycle and then 80 mg/m2 plus cisplatin 80 mg/m2 on day 1 every 3 weeks followed for patients with objective response or stable disease by consolidation therapy with oral vinorelbine at 80 mg/m2 weekly on patients with unresectable localised or metastatic non-small-cell lung cancer (NSCLC). The primary endpoint was tumor response. The secondary objectives were progression free-survival, overall survival and toxicity assessment. Visual analogue scales (VAS) filled by the patients were also used to evaluate subjective changes under treatment, reflecting patients' clinical benefit. RESULTS: Fifty-six patients enrolled into the study from April 2001 to April 2002 received the combination regimen. Twenty-five patients (43.9%) also received the subsequent consolidation treatment. Partial tumor responses were obtained in 13 patients (26.5%, 95% CI 15.0-41.1) of 49 evaluable patients. Stable disease was observed in 22 (44.9%) of patients. The median duration of response was 6 months (95% CI 4.3-8.2). The median progression free-survival was 4.2 months (95% CI 2.8-6). The median overall survival time was 10 months (95% CI 7.4-14) and the 1 year survival was 42.6%. The main toxicities recorded were haematological. Grade 3 and 4 neutropenia were observed in 16 patients (29.1%). Nausea, vomiting and fatigue were the major non-haematological toxicities reported. Among the symptoms recorded by the patients on VAS scales (appetite, fatigue, pain, cough, dyspnea, haemoptysis), except anorexia, all symptoms were improved during the combination therapy and in the consolidation phase. CONCLUSION: This study confirms that the efficacy of the cisplatin/oral vinorelbine combination in NSCLC is comparable to cisplatin/I.V. vinorelbine. This study also suggests that consolidation therapy with vinorelbine alone may probably prolong the efficacy of the combination regimen. The convenience offered to patients by an oral form of vinorelbine is a definite asset for consolidation therapy.

Administration, Oral↗
PubMed2004

Nuclear stopping in Au+Au collisions at square root of S(NN)=200 GeV.

Transverse momentum spectra and rapidity densities, dN/dy, of protons, antiprotons, and net protons (p-p) from central (0%-5%) Au+Au collisions at square root of S(NN)=200 GeV were measured with the BRAHMS experiment within the rapidity range 0</=y</=3. The proton and antiproton dN/dy decrease from midrapidity to y=3. The net-proton yield is roughly constant for y<1 at dN/dy approximately 7, and increases to dN/dy approximately 12 at y approximately 3. The data show that collisions at this energy exhibit a high degree of transparency and that the linear scaling of rapidity loss with rapidity observed at lower energies is broken. The energy loss per participant nucleon is estimated to be 73+/-6 GeV.

Journal Article↗
PubMed2004

Quantification of alpha-subunit isoforms of Na,K-ATPase in rat resistance vessels.

AIM: Rat mesenteric resistance vessels (RV) were characterized with respect to concentration of individual alpha-subunit isoforms of Na,K-ATPase. METHODS: Total vessel homogenates were used to avoid any loss or subfractionation of membranes. They were applied to sodium dodecyl sulphate gels and, for calibration, in parallel lanes were run purified rat Na,K-ATPase preparations with known isoform distribution and content. The capacity per mg protein for Na+-dependent 32P-phosphorylation of Na,K-ATPase isolated from rat kidney was used for alpha1 calibration and that for high-affinity (3H)ouabain binding of Na,K-ATPase isolated from rat brain was used for (alpha2 + alpha3) calibration. Western blots containing homogenate proteins and reference enzyme were incubated with isoform-specific antibodies and radiolabelled secondary antibodies. The signals from adjacent alpha spots were used for qualitative and quantitative characterization of rat vessels. RESULTS: A concentration of 100.7 +/- 14.4 pmol (n = 11) per g wet weight of the alpha1-isoform containing Na,K-ATPase was found in RV from 12-14-week rats. A much lower and more unreliable content of alpha2- and alpha3-isoforms was found. These ouabain-sensitive isoforms seem to represent a maximum of 5-10% each compared with the ouabain-insensitive rat alpha1-isoform. CONCLUSIONS: The isoform pattern in RV, in which the isoform with high/intermediate Na+-affinity is the absolutely dominating one representing nearly all sodium pumps in this tissue, is very different from that seen in rat skeletal muscles. Due to the high content of the ouabain-insensitive alpha1-isoform in rat RV this species would seem a less relevant model in studies addressing a role of cardiac glycosides and putative endogenous ouabain-like factors in hypertension.

Animals↗
PubMed2003

Synergistic effects of pyrantel and the febantel metabolite fenbendazole on adult Toxocara canis.

Pyrantel embonate and febantel are both constituents of Drontal Plus and Drontal Puppy broad spectrum anthelmintics for dogs. The effects of pyrantel and the febantel metabolite fenbendazole were investigated against Toxocara canis in-vitro by studying changes in worm motility and tissue damage. Pyrantel and fenbendazole were added to worms incubated in media for 8 h at the following concentrations: pyrantel: 12.2 microg, 25 microg, or 50 microg; fenbendazole: 50 microg, 100 microg or 200 microg; mixture of pyrantel and fenbendazole: 12.2 microg p + 50 microg f, 25 microg p + 100 microg f, 50 microg p + 200 microg f. Following this 8 h incubation period, one group of the worms was immediately fixed and studied by light- and electron microscopical examination. Other groups have been observed for further 8 h periods up to 56 hours and then studied in the same way.

Animals↗
PubMed2003

Transverse-momentum spectra in Au+Au and d+Au collisions at sqrt[s(NN)]=200 GeV and the pseudorapidity dependence of high-p(T) suppression.

We present spectra of charged hadrons from Au+Au and d+Au collisions at sqrt[s(NN)]=200 GeV measured with the BRAHMS experiment at RHIC. The spectra for different collision centralities are compared to spectra from p+(-)p collisions at the same energy scaled by the number of binary collisions. The resulting ratios (nuclear modification factors) for central Au+Au collisions at eta=0 and eta=2.2 evidence a strong suppression in the high p(T) region (>2 GeV/c). In contrast, the d+Au nuclear modification factor (at eta=0) exhibits an enhancement of the high p(T) yields. These measurements indicate a high energy loss of the high p(T) particles in the medium created in the central Au+Au collisions. The lack of suppression in d+Au collisions makes it unlikely that initial state effects can explain the suppression in the central Au+Au collisions.

Journal Article↗
PubMed2003

A light and electron microscopic study on the synergistic effect of pyrantel and the febantel metabolite febendazole on adult Toxocara canis in vitro.

In the present study, we investigated the in vitro effects on the motility and morphology of tissues and organs of Toxocara canis of the two drug components of Drontal Plus and Welpan, pyrantel and fenbendazole (the active metabolite of the prodrug febantel), both alone and in combination. Although there was no significant difference observable between the effects of the single drugs and the drug combination on worm motility, the synergistic effect of pyrantel and fenbendazole was manifested by morphological alterations seen by light and electron microscopy. Thus, an earlier onset of damage to worm tissues and organs could be observed compared to the application of the individual drugs. In addition, a higher degree of damage and an increased number of vital organs were involved. There was dramatic, significantly greater and irreversible damage to the hypodermis, longitudinal muscle, intestine, nerve cords and genital organs induced by the pyrantel/fenbendazole combination. We hypothesise that these synergistic effects will also take place when dogs are treated either with Drontal Plus or Welpan in which lower dosages will be sufficient to destroy the worms.

Animals↗
PubMed2003

Rapidity dependence of charged antihadron to hadron ratios in Au+Au collisions at sqrt[s(NN)]=200 GeV.

We present ratios of the numbers of charged antihadrons to hadrons (pions, kaons, and protons) in Au+Au collisions at sqrt[s(NN)]=200 GeV as a function of rapidity in the range y=0-3. While the ratios at midrapidity are approaching unity, the K(-)/K(+) and p;/p ratios decrease significantly at forward rapidities. An interpretation of the results within the statistical model indicates a reduction of the baryon chemical potential from mu(B) approximately 130 MeV at y=3 to mu(B) approximately 25 MeV at y=0.

Journal Article↗
PubMed2002

Pseudorapidity distributions of charged particles from Au + Au collisions at the maximum RHIC energy, square root[s(NN)] = 200 GeV.

We present charged-particle multiplicities as a function of pseudorapidity and collision centrality for the 197Au+197Au reaction at square root[s(NN)] = 200 GeV. For the 5% most central events we obtain dN(ch)/deta/(eta = 0) = 625+/-55 and N(ch)/(-4.7< or =eta < or =4.7) = 4630 +/- 370, i.e., 14% and 21% increases, respectively, relative to square root[s(NN)] = 130 GeV collisions. Charged-particle production per pair of participant nucleons is found to increase from peripheral to central collisions around midrapidity. These results constrain current models of particle production at the highest RHIC energy.

Journal Article↗
PubMed2002

Myocardial infarction in an urban population: worse long term prognosis for patients from less affluent residential areas.

STUDY OBJECTIVE: The objective in this follow up study from the Malmö myocardial infarction register has been to assess whether long term survival following discharge after first myocardial infarction has any relation with the socioeconomic environment and to assess to what extent intra-urban differences in mortality from ischaemic heart disease can be accounted for by covariance with long term survival following discharge after acute myocardial infarction. DESIGN: Register based surveillance study. SETTING: Seventeen residential areas in the city of Malmö, Sweden. PARTICIPANTS: The cohort contains all 2931 male and 2083 female patients with myocardial infarction who were discharged for the first time between 1986-95 from Malmö University Hospital. MAIN RESULTS: During the on average 4.9 years of follow up 55% of the patients died. The sex adjusted and age adjusted all cause mortality rate/1000 patient years ranged between residential areas from 85.5 to 163.6. The area specific relative risk of death after discharge was associated with a low socioeconomic score, r=-0.56, p=0.018. Major risk factors for cardiovascular disease were more prevalent in areas with low socioeconomic score and low rates of survival. Of the intra-urban differences in mortality from ischaemic heart disease, 41% could be accounted for by differences with regard to the survival rate after discharge. CONCLUSIONS: The results are compatible with the hypothesis that the socioeconomic environment plays an important part in the survival rate of patients with myocardial infarction. To assess the preventive potential, the extent to which socioeconomic circumstances covary with severity of disease, respectively with the use and compliance with secondary preventive measures, needs to be evaluated.

Age Factors↗
PubMed2002

Development of a larval bioassay for susceptibility of cat fleas (Siphonaptera: Pulicidae) to imidacloprid.

Strategies for controlling cat fleas, Ctenocephalidesfelisfelis (Bouché), have undergone dramatic changes in the past 5 yr. With the advent of on-animal treatments with residual activity the potential for the development of insecticide resistance increases. A larval bioassay was developed to determine the baseline susceptibility of field-collected strains of cat fleas to imidacloprid. All four laboratory strains tested showed a similar level of susceptibility to imidacloprid. Advantages of this bioassay are that smaller numbers of fleas are required because flea eggs are collected for the test. Insect growth regulators and other novel insecticides can also be evaluated. Using a discriminating dose, the detection of reduced susceptibility in field strains can be determined with as few as 40 eggs.

Acetone↗
PubMed2001

Rapidity dependence of antiproton-to-proton ratios in Au+Au collisions at square root of (sNN) = 130 GeV.

Measurements, with the BRAHMS detector, of the antiproton-to-proton ratio at midrapidities and forward rapidities, are presented for Au+Au reactions at square root of [s(NN)] = 130 GeV, and for three different collision centralities. For collisions in the 0%-40% centrality range, we find N(&pmacr;)/N(p) = 0.64+/-0.04((stat))+/-0.06((syst)) at y approximately 0, 0.66+/-0.03+/-0.06 at y approximately 0.7, and 0.41+/-0.04+/-0.06 at y approximately 2. The ratios are found to be nearly independent of collision centrality and transverse momentum. The antiproton and proton rapidity densities vary differently with rapidity, and indicate a significant degree of collision transparency, although a net-baryon free midrapidity plateau (Bjorken limit) is not yet reached.

Journal Article↗
PubMed2001

Two-kaon correlations in central Pb+Pb collisions at 158 a GeV/c.

Two-particle interferometry of positive kaons is studied in Pb+Pb collisions at mean transverse momenta approximately 0.25 and 0.91 GeV/c. A three-dimensional analysis was applied to the lower p(T) data, while a two-dimensional analysis was used for the higher p(T) data. We find that the source-size parameters are consistent with the m(T) scaling curve observed in pion-correlation measurements in the same collisions, and that the duration time of kaon emission is consistent with zero within the experimental sensitivity.

Journal Article↗