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Biomedical subjects

W Lange

Publications and source records attributed to W Lange.

At least 19 recordsLinked to original sources
PubMed2006

Competition of pattern forming instabilities due to phase front curvature in an optical system.

In this paper we analyze experimentally and theoretically the competition between two pattern forming instabilities in a single mirror feedback scheme with sodium vapor as the nonlinear medium. Two types of structures with different transverse wave numbers are observed experimentally, if the spatial phase modulation of the light field is varied. This phenomenon results from the combination of a nonlinear self-lensing effect on the one hand and of the externally controlled phase front curvature of the light field on the other. A linear stability analysis yields two instabilities whose length scales match quite well the experimental findings. Further analysis reveals the mechanism of length-scale selection in this system and demonstrates the possibly crucial role of phase front curvature in optical pattern formation.

Journal Article↗
PubMed2005

A new European perspective of influenza pandemic planning with a particular focus on the role of mammalian cell culture vaccines.

Sixteen EU scientists and doctors were interviewed about pandemic planning using psychometric methods applied to a scientific problem for the first time. Criticism was aimed at countries which have no plan whatsoever, the majority of nations. Many such countries have not invested in scientific infrastructure and public health. Amongst the 15 or so published pandemic plans a lack of detail was identified. Of particular need was investment into avian virus vaccine stocks (H1-15), prepared licenses of vaccine and pre purchase and agreed distribution, investment into stocks of antivirals, antibiotics and masks. Most but not all members of the group predicted a global outbreak within 5 years, most probably starting in SE Asia. However it was recognised that a pandemic could start anywhere in the world which had juxtaposition of young people, chickens, ducks and pigs. Mammalian cell culture production using wild type virus with the production factory at category III levels of security was exemplified. Antivirals would be essential to ameliorate the first wave of infection although significant quantities of cell grown vaccine could be produced if, as in 1918, 1957 and 1968 there is a long period between the first virus isolation and person to person spread. The wider scientific community is more energised than previously for very serious preparations to be in place way before the outbreak begins as this is a major public health problem, completely dwarfing concerns about bioterrorism.

Animals↗
PubMed2005

Observation of a discrete family of dissipative solitons in a nonlinear optical system.

We report on the observation of a discrete family of spatial dissipative solitons in a simple optical pattern forming system, which is based on a modified single-mirror feedback arrangement. After a pitchfork bifurcation the system possesses two (nearly) equivalent coexisting states of different polarizations. The spatial solitons correspond to excursions from one of the two states serving as a background state towards the other one. The members of the soliton family differ in the number of high-amplitude radial oscillations. The observations are in good agreement with numerical simulations and general expectations for dissipative solitons.

Journal Article↗
PubMed2004

[Influenza surveillance in Germany].

Currently, two systems for the monitoring of influenza are in use in Germany, which, if appropriate cooperation is forth-coming, may complement each other: The system of the influenza working group at the Robert Koch Institute that makes use of the measuring parameters ARD (acute respiratory disease) and viral detection (PCR/isolation) together with a sentinel system of reporting physicians to establish morbidity and mortality, provides information via the Internet. The delay associated with reporting is approximately one week and is longer for viral isolation. Cooperation in the European influenza surveillance system (EISS) and,via the National Reference Centers, with the WHO global monitoring system. The RealFlu system employing the parameters ILI (influenza-like illness) and rapid influenza tests with a sentinel system of reporting physicians, which is designed to provide accurate and regional information on influenza activity. The information is updated on a day-to-day basis, and is available to anyone on the Internet.

Germany↗
PubMed2004

Long-term follow-up after high-dose chemotherapy and autologous stem-cell transplantation for high-grade B-cell lymphoma suggests an improved outcome for high-risk patients with respect to the age-adjusted International Prognostic Index.

BACKGROUND: To evaluate the long-term benefit from high-dose chemotherapy (HDCT) with autologous stem-cell transplantation (ASCT), as part of the initial treatment for patients with chemosensitive, high-grade B non-Hodgkin's lymphoma (hg B-NHL), stratified according to the age-adjusted International Prognostic Index (aaIPI). PATIENTS AND METHODS: Eligible patients were 33 consecutive hg B-NHL patients responding to first-line chemotherapy and fulfilling at least one of the following criteria: stage III or IV, bulky disease, elevated lactate dehydrogenase or failure to achieve complete remission (CR). Twenty-two of 33 patients (67%) had two or three risk factors with respect to the aaIPI. All patients received HDCT with ASCT after a minimum of 6 weeks of VACOP-B standard therapy and VIP-E for mobilization. RESULTS: After ASCT, 31 patients (94%) achieved CR. No treatment-related death occurred. The cumulative incidence of relapse at a medium follow-up of 10 years is 16% for 31 of 33 patients achieving CR. Twenty-five of 33 patients are in sustained CR with a disease-free survival of 76% [95% confidence interval (CI) 67% to 86%]. The overall survival at a median follow-up of 122 months (range 86-148) is 79% (95% CI 68% to 89%). CONCLUSIONS: The results suggest that up-front HDCT with ASCT may improve long-term outcome in high-risk patients with chemotherapy-sensitive hg B-NHL when compared to historic populations treated solely with dose-intense chemotherapy. We observed that long-term survival of high-risk (two to three risk factors) patients is comparable to low-risk (zero to one risk factor) patients after HDCT and ASCT with a low incidence of late relapse.

Adult↗
PubMed2003

Direct measurement of multiple instability regions via a Fourier filtering method in an optical pattern forming system.

We determine the limits of stability of the homogeneous state of a pattern forming optical system in dependency on the wave number by experimental means. The measurement becomes feasible by adopting a scheme based on a Fourier filtering technique. The system under study is a single-mirror feedback arrangement using sodium vapor as the nonlinear medium. The experiment confirms the existence of multiple instability regions of the homogeneous state expected by theory. The measurements do not agree quantitatively with the marginal stability curve determined by a linear stability analysis of an infinitely extended homogeneous system. We study the system numerically and demonstrate that the results of the simulations for the case of a Gaussian beam can be reproduced by a simple modification of the linear stability analysis which accounts for the finite diameter of the input beam. This explains the wave number dependent systematic deviations between the experiment and the linear stability analysis of the infinitely extended system.

Journal Article↗
PubMed2003

Quantitative analysis of mixed chimerism following allogeneic bone marrow transplantation using telomere flow-FISH.

Assessment of mixed chimerism is of particular interest for allogeneic bone marrow or peripheral blood stem cell transplantation with reduced-intensity conditioning in order to study contribution of donor-type and host-type lymphohematopoiesis. Because the length of telomere repeat sequences is frequently shorter in leukemic compared to normal hematopoietic cells, this telomere repeat polymorphism might be a useful marker to analyze mixed chimerism in selected patients with short telomeres. Recently, fluorescence in situ hybridization and flow cytometry (flow-FISH) have been shown to be valuable tools to analyze the mean telomere length in hematopoietic cells. Here, we demonstrate in a case study on a patient with chronic lymphocytic leukemia (CLL) that telomere flow-FISH can in principle be exploited to quantitate the amount of donor- and host-type cells for chimerism analysis based on distinct histogram distributions which reflect cell populations with different telomere length.

Bone Marrow Transplantation↗
PubMed2003

Self-organized superlattice patterns with two slightly differing wave numbers.

We report on the observation of superlattices that occur spontaneously in a nonlinear optical system with O(2) symmetry. A secondary bifurcation from hexagons yields patterns formed by twelve wave vectors. Besides irregular patterns these may either be quasiperiodic patterns or superlattices built from two classes of wave vectors differing slightly in their length. Both classes of wave vectors stem from only one pattern-forming instability. The wave vectors fit on a hexagonal or a square grid. In the former case the set of wave vectors can be decomposed into two hexagonal triads, whereas in the case of the square grid squeezed triads occur.

Journal Article↗
PubMed2003

[Influenza--the last big epidemic. What makes it so dangerous?].

In Germany, influenza lays low millions--and causes up to 15,000 deaths--every year. Three factors in particular are responsible for the severity of the disease: the cytocidal action of the virus--which, via hematogeneous spread, can involve not only the respiratory tract but also other organs such as the heart--, the immune response with fever and the production of pro-inflammatory cytokines, and bacterial superinfection of the virally predamaged respiratory mucosa. A particular threat is posed by influenza pandemics, which are usually associated with extremely high mortality and morbidity rates. The development of pandemics is furthered by the potential of the viral genome to undergo a so-called shift, as a result of which a reservoir of, for example, avian influenza A viruses can give rise to subtypes that are a danger to humans, and against which there is initially no protection. While the deaths caused by an epidemic are to be seen largely among old and multimorbid people, a pandemic also endangers the health and life of young and healthy persons.

Cause of Death↗
PubMed2002

Eightfold quasipatterns in an optical pattern-forming system.

Quasipatterns with an eightfold rotational symmetry and irregular two- and three-mode patterns are found in an experiment on optical pattern formation. The patterns exist in the transverse cross section of a laser beam that traverses a system built from a sodium vapor cell and a plane feedback mirror with a quarter-wave plate placed into the feedback loop. The occurrence of the quasipatterns is reproduced by numerical simulations and explained by amplitude equations that contain only odd-order terms and are derived from the microscopic model. The selection process is governed by the angle dependence of the cubic cross coupling coefficients in the amplitude equations. Up to our knowledge it provides the first experimental example for a stabilization mechanism proposed earlier that is based on an oscillatory dependence of the cubic cross coupling coefficient on the angle between the interacting wave vectors. The relationship to the prediction of quasipatterns in a similar setup without additional wave plate [Phys. Rev. A 53, 1072 (1996)] is discussed.

Journal Article↗
PubMed2002

Real-time influenza surveillance in Germany--results of a pilot project.

Real-time surveillance information is the prerequisite for accurate influenza diagnosis followed by appropriate treatment of acute influenza with neuraminidase inhibitors. With REALFLU trade mark Surveillance, Hoffmann-La Roche has developed an international early warning system for influenza. The feasibility of the newly developed real-time influenza surveillance in Germany was tested and the results were compared with those of the established German influenza sentinel system of Influenza Study Group (Arbeitsgemeinschaft Influenza, AGI). The evaluation of the REALFLU trade mark Surveillance was performed during the winters of 1999/2000 and 2000/2001. The percentage of influenza-like illnesses among patients seen by the reporting physicians and positives of the Roche Influenza A/B Rapid Test were reported daily by internet, evaluated and could be called up on dynamic internet web pages real-time. The group of project participants could at any time call up the evaluations of the current data on password-protected internet web pages. A retrospective comparison with data obtained by the AGI showed good agreement between the two systems. Even better agreement was obtained on comparing the data with the virus isolates of the National Reference Centers (NRZ). This confirms the reliability of the selected methodology. REALFLU trade mark Surveillance provided information about influenza outbreaks 1-2 weeks earlier than NRZ and the AGI. The results show that it is possible and reasonable to conduct influenza surveillance on a real-time basis. In an overall context of REALFLU trade mark Surveillance, the German pilot project was capable of reflecting the influenza situation on a real-time and regionalized basis during both winters. The Roche Influenza A/B Rapid test proved to be a useful surveillance tool.

Age Distribution↗
PubMed2002

Treatment and prophylaxis of severe infections in neutropenic patients by granulocyte transfusions.

Bacterial and fungal infections are the main cause of morbidity and mortality in neutropenic patients. To resolve infections, an adequate number of functional granulocytes is required. Successful treatment of severe infections with granulocyte transfusions is strongly dependent on an adequate number of transfused cells. In this study, 42 neutropenic patients received rhG-CSF-stimulated granulocyte transfusions (GTXs). Of these patients, 18 with severe infections during neutropenia and 8 in a high-risk situation, as defined by severe infections during previous periods of neutropenia or increasing infectious parameters during prolonged neutropenia, received a median of three GTXs (range 1-25), containing a median total of 2.62x10(10) leukocytes (range 0.3-8.61x10(10)). A further 16 patients in a pilot study received prophylactic GTX, consisting of a median of three GTXs (range 1-4) containing a median total of 3.20x10(10) leukocytes (range 0.73-8.51x10(10)). Out of 18 patients with severe infections, 12 improved clinically or showed a resolution of infection after GTX. All 8 patients in a high-risk situation showed a stable clinical course without serious infections. Prophylactic GTX did not result in significant differences with regard to infectious parameters. The median number of transfused platelet units during the course of cytopenia was significantly reduced (13.5 units vs 22.0 units, P<0.02) compared to the control group. For the treatment of infections during neutropenia, rhG-CSF-stimulated granulocyte transfusions are safe and a promising approach.

Adolescent↗
PubMed2002

[Is the borderline personality disorder a complex post-traumatic stress disorder? - The state of research].

Regarding the high prevalence of traumatic experiences in patients with borderline personality disorders (BPD), we review the available literature focussing on the hypothesis that BPD is a subtype of trauma associated disorders. The criteria of BPD, of complex post-traumatic stress disorders (PTSD), and of disorders of extreme stress not otherwise specified (DESNOS) substantially overlap. Research of the long-term course of BPD and PTSD, trauma research, and research of vulnerability in both disorders yielded converging results. Neuropsychological deficits in BPD and PTSD as well as psychoendocrinological and neuroimaging studies in BPD und PTSD also revealed common features. A pathogenetic specificity of individual etiologic factors does not appear to exist, however the assumption of a diathesis-stress model with traumatisation as a necessary but etiologically insufficient condition seems justified. Further research will have to prove BPD as a complex and early-onset post-traumatic stress disorder after multiple and/or chronic (type II) traumatic experiences during childhood and/or youth. Definitive conclusions require further research efforts.

Adolescent↗
PubMed2002

Effects of lactulose on the intestinal microflora of periparturient sows and their piglets.

The periparturient period of animals (and humans) is very stressful and influenced by the microecosystem of the gastrointestinal tract (GIT). Performance and productivity of animal husbandry depend on the health of animal mothers and their offspring. We investigated the influence of prebiotic amounts of lactulose in sows and their piglets. Two experimental trial sows received daily 30 ml lactulose, 71 field trial sows received daily 45 ml lactulose during their periparturient period (10 days before until 10 days after parturison). The weaners of trial sows received 15 ml lactulose per 1 kg baby food 10 days before and 10 days after weaning.The effect of lactulose was recorded by performance parameters like number of piglet born alive, losses until weaning, body mass of piglets, daily weight gain of weaners until 35 days after weaning. The effect of lactulose on GIT microflora was estimated by bacterial counts of faeces of sows (total aerobic bacteria, Gram-negative bacteria, Clostridium (C.) perfringens). In order to show a previously unknown effect of lactulose we investigated the levels of antibodies to phospholipase C (PLC) of C. perfringens in plasma of experimental sows and in colostral and ripe milk of field sows. Lactulose influenced the performance parameters of sows in a non-significant way. In case of weaners we recorded significant daily weight gains. Lactulose significantly influenced total aerobic bacterial counts, C. perfringens counts in faeces of sows 20 days after parturison. Under experimental conditions it was shown that trial sows and their piglets had higher IgG-antibody levels to C. perfringens PLCs than the control animals. Similar results were found under field conditions. Trial sows had significant higher IgG-anti LPS (J5) antibodies in milk 10 days after birth.

Animal Feed↗
PubMed2002

Relation between homocysteine and non-fatal stroke in peripheral arterial disease.

There are currently no data on whether high total serum homocysteine (tHcy) is predictive for cerebrovascular events in patients with symptomatic peripheral arterial disease (PAD). Therefore, the purpose of this study was to determine whether high tHcy levels were related to the evidence of non-fatal stroke in PAD. Evidence of non-fatal atherothrombotic stroke events was verified in 450 consecutive male patients, admitted for inpatient treatment of symptomatic PAD. The extent of carotid stenosis was evaluated by colour duplex Doppler measurement and fasting tHcy was determined by high-performance liquid chromatography. Within the population of 450 PAD patients a documented history of ischaemic stroke was evident in 50 subjects. The median tHcy values were significantly higher in PAD patients with stroke (18.6 micromol/l) than in PAD patients without stroke (15.1 micromol/l, P < 0.001). Logistic regression analysis revealed that tHcy was an independent and significant predictor (P=0.001) with an odds ratio (OR) of 1.37 for an increment of 5 micromol/l. In this multivariate model, diabetes mellitus (OR=2.34, P=0.011) and carotid stenosis > or =50% (OR=2.59, P=0.005) were also independently related to clinical cerebrovascular disease in PAD. In conclusion, the present study demonstrates an association of tHcy and evidence of non-fatal atherothrombotic stroke in patients with symptomatic PAD. This could be important, as a reduction of elevated tHcy concentrations by vitamin supplement might decrease the high frequency of cerebrovascular complications in PAD patients.

Aged↗
PubMed2002

[ACN (Automatic Collision Notification)--reducing fatalities in traffic accidents by automated accident reporting].

To improve patient's outcome of seriously injured occupants after vehicle accident rescue should be performed as soon as possible. While the rescue-time-period after EMS alarming is well-defined the rescue-time-period before EMS-alarm is very variable from minutes to several hours. To reduce the rescue-time-period between accident occurrence and EMS-alarm the Automatic Collision Notification (ACN) was developed. The ACN is a new invehicle-equipment which detects a severe vehicle crash and alarms via cellular phone the EMS automatically. Simultaneously the exact accident location is transmitted (GPS). Official data of the European Community predict a 15% reduction of road traffic fatalities with ACN. Thereby the economical benefit of about 561 million [symbol: see text] could be calculated for Germany 2000.

Accidents, Traffic↗