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J Wagner

Publications and source records attributed to J Wagner.

At least 37 records · Page 2Linked to original sources
PubMed2004

Self-diffusion of rodlike and spherical particles in a matrix of charged colloidal spheres: a comparison between fluorescence recovery after photobleaching and fluorescence correlation spectroscopy.

The fluorescence recovery after photobleaching (FRAP) method and the fluorescence correlation spectroscopy (FCS) have been applied on suspensions of highly charged colloidal spheres with a small content of rod-shaped tobacco mosaic virus (TMV) particles. Since these methods only determine the self-diffusion coefficient of the fluorescently labeled species, D(S) of the rods and the spheres could independently be measured. The ionic strength of the dispersion medium has been varied to measure self-diffusion of rods and spheres in dependence on the degree of order of the matrix spheres. In contrast to FRAP, which allows the determination of the long-time self-diffusion coefficient D(S) (L), FCS measures self-diffusion on a shorter time scale. Thus a comparison of the results that were obtained by FCS and FRAP, in combination with Brownian Dynamics simulations, gives insight into the time dependence of the self-diffusion coefficient of an interacting colloidal system. As the mean interparticle distance of the matrix is of the same order of magnitude as the length of a TMV rod, the rotational motion is influenced by the assembly of spheres around a TMV particle. Since FCS is sensitive both to translational and rotational motion, whereas FRAP, which probes the diffusion at much larger length scales, is only sensitive to the translational motion of TMV, the comparison of diffusion coefficients measured employing FRAP and FCS can give some insights in the rotational diffusion: the experimental data indicate a slowing down of the rotational motion of a TMV rod with increasing structural order of the matrix spheres.

Journal Article↗
PubMed2004

[Long-term central venous lines and their complications].

The implantation of permanent (> 14 days) central venous catheters is constantly increasing, accelerated by a trend toward outpatient therapies. Subcutaneous tunneled and non-tunneled catheters as well as port systems are available. The interventional radiologist plays an important role in the implantation of central venous catheters as well as in detection and treatment of any complications. Various access ways via peripheral and central veins are described and the implantation techniques for the different systems explained. The use of peel-away sheaths allows the radiologist to implant subcutaneous tunneled catheters via the Seldinger technique without surgical preparation. Procedure-related early and late complications may occur, and the radiologist plays an important role in the surveillance and management of catheter-associated complications. This review demonstrates the different catheter systems and implantation techniques.

Catheterization, Central Venous↗
PubMed2004

Pollination effectiveness and pollen dispersal in a Rhododendron ferrugineum (Ericaceae) population.

Many alpine plants are predominantly outcrossing, thus plant reproductive success is highly dependent on effectiveness of pollinators. How pollinators transfer pollen from one flower to another is of great interest in understanding the genetic structure in plant populations. We studied (1) the role and effectiveness of insect visitors for pollination, and (2) their contribution as pollen vectors for gene dispersal in a Rhododendron ferrugineum population. Various insect visitors were recorded, including Hymenoptera, Diptera, Coleoptera, and Lepidoptera. The most frequent and effective insects were honey bees and bumblebees. Muscid flies were considered as important pollinators, particularly due to their relatively high visitation rate. Syrphid flies, Formicidae, and Coleoptera were ineffective in transporting pollen, while the effectiveness of Lepidoptera and Empididae was negligible. A fluorescence labelling experiment revealed that pollen dispersal was restricted (0 - 2 m) in a dense R. ferrugineum stand and decreased in a leptokurtic fashion. This might lead to geitonogamous self-pollination that could explain the close relationship between individuals found in genetic studies of R. ferrugineum. However, some pollen grains may travel 40 - 45 m, which implies the occurrence of cross-pollination through the foraging activities of bumblebees and honey bees.

Animals↗
PubMed2004

Environmental tobacco smoke leakage from smoking rooms.

Twenty-seven laboratory experiments were conducted in a simulated smoking room to quantify rates of environmental tobacco smoke (ETS) leakage to a nonsmoking area as a function of the physical and operational characteristics of the smoking room. Data are presented for the various types of leakage flows, the effect of these leaks on smoking room performance and nonsmoker exposure, and the relative importance of each leakage mechanism. The results indicate that the first priority for an effective smoking room is to maintain it depressurized with respect to adjoining nonsmoking areas. The amount of ETS pumped out by the smoking room door when it is opened and closed can be reduced significantly by substituting a sliding door for the standard swing-type door. An "open doorway" configuration used twice the ventilation flow of those with smoking room doors, but yielded less reduction in nonsmoker exposure. Measured results correlated well with results modeled with mass-balance equations (R(2) = 0.82-0.99). Most of these results are based on sulfur hexafluoride (SF(6)) tracer gas leakage. Because five measured ETS tracers showed good correlation with SF(6), these conclusions should apply to ETS leakage as well. Field tests of a designated smoking room in an office building qualitatively agreed with model predictions.

Air Movements↗
PubMed2004

Increased lymphoid tissue apoptosis in baboons with bacteremic shock.

The molecular mechanisms of immune cell apoptosis during sepsis remain unclear. Two young adult baboons (Papio sp.) received a lethal dose of live Escherichia coli and were sacrificed at either 16 (for animal welfare concerns) or 24 h post-septic shock. An additional baboon, which received no bacteria, served as a control. Necropsy was performed immediately with subsequent immunohistochemical staining of lymphoid tissue. Immunohistologic analysis of tissues from the septic baboons revealed marked systemic lymphocyte apoptosis occurring in all lymphoid tissues examined. Focally, pyknotic and karyorrhectic lymphocytes demonstrated activation of a mitochondrial-dependent cell death pathway (active caspase 9 and apoptosis-inducing factor). Other regions demonstrated apoptotic lymphocytes with activation of a death receptor-dependent cell pathway (Fas ligand). Thus, we have demonstrated for the first time in primates that overwhelming gram-negative bacteremia produces an early and profound lymphocyte death that occurs through multiple cell death pathways. Bacteremic shock in the baboon may be an appropriate model for studying experimental therapies aimed at blocking lymphocyte apoptosis because their response appears comparable to humans dying from sepsis.

Animals↗
PubMed2003

Long-term clinical performance and longevity of gold alloy vs ceramic partial crowns.

Cast gold partial crowns (CGPC) are an accepted means of restoring posterior teeth. For aesthetic reasons, gold alloys are being increasingly substituted with ceramics. The aim of the present study was to investigate retrospectively the long-term clinical performance and survival of CGPC and compare the results to the ones already reported for ceramic partial crowns (CPC). The CGPC group consisted of 42 patients (24 male, 18 female) randomly sampled from a total of 106 patients with CGPC, with one restoration per patient. The CPC group consisted of 22 patients with a total of 42 restorations. Both types of restoration were done by one experienced dentist. Another two experienced dentists who were not involved in performing the restorations rated both kinds of partial crowns using the modified United State Public Health Service (USPHS) criteria [14]. The Median age of the CGPC was 57 months (range 3-157) and of the CPC and 63 months (range 24-72). Forty-one (98%) of the CGPC and 27 (64%) of the CPC were placed in molars, the rest in premolars. In each group, 40 (95%) restorations were still functioning without any necessity of replacement. Two teeth with CGPC, in situ for 4.5 and 11 years, respectively, had been extracted for periodontal reasons. Two CPC fractured and had to be replaced after 2 and 6.5 years in situ. The USPHS criteria results were similarly good for the gold and ceramic groups. Kaplan-Meier analysis revealed survival probabilities of 72+/-21% and 96+/-4% after 13 and 7 years, respectively, for the CGPC. Survival of the CPC was 81+/-15% after 7 years. No statistically significant difference among survival functions of CGPC and CPC was found. From this data, it can be concluded that the longevity of CPC is not inferior to that of gold alloys. However, more long-term studies comparing the clinical performance and longevity of these two types of indirect restoration in the posterior region with larger numbers of restorations are desirable.

Bicuspid↗
PubMed2003

Vertical growth phase and positive sentinel node in thin melanoma.

Sentinel node (SN) status is the most important prognostic factor for localized melanoma. Usually, patients with Breslow thickness of less than 1.0 mm are not included in SN protocols. However, the literature presents a rate ranging from 3 to 7% of nodal recurrence in thin melanoma. Ulceration, regression and high mitotic rate have been considered to be indications for an SN biopsy. The metastatic potential of the vertical growth phase is uncertain. To correlate pathological features in thin melanoma with SN metastasis, we reviewed 358 patients submitted to SN biopsy. Seventy-seven patients with lesions of 1 mm or smaller were included in the study group. Histological evaluation of the primary tumor included thickness, Clark level, mitotic rate, ulceration, regression, and growth phase. Lymphoscintigraphy was performed on all patients. Lymphatic mapping and gamma probe detection were both used for SN biopsy. Histological examination of SN consisted of hematoxylin-eosin and immunohistochemical staining. Median follow-up was 37 months. Six patients had micrometastases. Statistical analysis by the Fisher test showed that ulceration (P = 0.019), high mitotic rate (P = 0.008) and vertical growth phase (P = 0.002) were positively correlated with micrometastases. If other studies confirm these results, more melanoma patients must be submitted to SN biopsy.

Adult↗
PubMed2003

The systems biology markup language (SBML): a medium for representation and exchange of biochemical network models.

MOTIVATION: Molecular biotechnology now makes it possible to build elaborate systems models, but the systems biology community needs information standards if models are to be shared, evaluated and developed cooperatively. RESULTS: We summarize the Systems Biology Markup Language (SBML) Level 1, a free, open, XML-based format for representing biochemical reaction networks. SBML is a software-independent language for describing models common to research in many areas of computational biology, including cell signaling pathways, metabolic pathways, gene regulation, and others. AVAILABILITY: The specification of SBML Level 1 is freely available from http://www.sbml.org/

Database Management Systems↗
PubMed2003

Efficacy and safety of DALI LDL-apheresis at high blood flow rates: a prospective multicenter study.

Direct adsorption of lipids (DALI) is the first LDL-apheresis method compatible with whole blood. Usually, the blood flow rate is adjusted at 60-80 ml/min, which results in session times of about 2 hr. The present study was performed to test the safety and efficacy of low-density lipoprotein cholesterol (LDL-C) and lipoprotein (a) [Lp(a)] removal by DALI at high blood flow rates in order to reduce treatment time. Thirteen chronic DALI patients in seven centers suffering from hypercholesterolemia (LDL-C 162 +/- 42 mg/dl at baseline) and coronary artery disease were treated on a weekly or biweekly basis by DALI apheresis. The blood flow rate QB was held constant for at least two sessions, respectively, and was increased from 60 to 80, 120, 160, 200, and 240 ml/min. All patients had pre-existing av-fistulas. The anticoagulation was performed by a heparin bolus plus ACD-A at a ratio of citrate:blood ranging from 1:20 to 1:90. Clinically, the sessions were well tolerated and only 26/201 sessions (12%) of the treatments were fraught with minor adverse events. Acute LDL-C reductions (derived from LDL-C levels determined by lipoprotein electrophoresis) averaged 72/66/60/53/50/48% for QB=60/80/120/160/200/240 ml/min. Lp(a) reductions were 68/67/62/60/58/56%, whereas HDL-C losses were < or =10%. Routine blood chemistries and blood cell counts remained in the normal range. Treatment times averaged 142/83/45 min at Qb=60/120/240 ml/min. On average, DALI LDL-apheresis could be performed safely and effectively at high blood flow rates up to at least 120 ml/min in patients with good blood access, which significantly reduced treatment time from 142 to 83 min (-42%).

Adsorption↗
PubMed2003

[Radiation-induced pacemaker malfunction].

As the number of implanted pacemakers and the incidence of malignant tumors increases, the probability of radiation-mediated pacemaker dysfunction increases. Radiation can substantially damage pacemaker electronics. We report here a case, with loss of communication after radiation therapy.

Breast Neoplasms↗
PubMed2003

Differences in the hemodynamic response to event-related motor and visual paradigms as measured by near-infrared spectroscopy.

Several current brain imaging techniques rest on the assumption of a tight coupling between neural activity and hemodynamic response. The nature of this neurovascular coupling, however, is not completely understood. There is some evidence for a decoupling of these processes at the onset of neural activity, which manifests itself as a momentary increase in the relative concentration of deoxyhemoglobin (HbR). The existence of this early component of the hemodynamic response function, however, is controversial, as it is inconsistently found. Near infrared spectroscopy (NIRS) allows quantification of levels of oxyhemoglobin (HbO(2)) and HbR during task performance in humans. We acquired NIRS data during performance of simple motor and visual tasks, using rapid-presentation event-related paradigms. Our results demonstrate that rapid, event-related NIRS can provide robust estimates of the hemodynamic response without artifacts due to low-frequency signal components, unlike data from blocked designs. In both the motor and visual data the onset of the increase in HbO(2) occurs before HbR decreases, and there is a poststimulus undershoot. Our results also show that total blood volume (HbT) drops before HbO(2) and undershoots baseline, raising a new issue for neurovascular models. We did not find early deoxygenation in the motor data using physiologically plausible values for the differential pathlength factor, but did find one in the visual data. We suggest that this difference, which is consistent with functional magnetic resonance imaging (fMRI) data, may be attributable to different capillary transit times in these cortices.

Adult↗
PubMed2002

Chemical surface analysis by Raman spectroscopy utilizing dimer vibrations.

We report on the investigation of reconstructed semiconductor surfaces by Raman spectroscopy from dimer vibrations. Localized modes of Te dimers on the (100) surface of the zinc blende II-VI semiconductor BeTe allow the analysis of Te- and Be-rich surface structures, as well as oxidation effects. The Te-rich surface exhibits one dimer-vibration mode at 165 cm(-1), while two modes appear at the Be-rich surface (157 and 188 cm(-1)). The mode assignment as dimer vibrations is underscored by their symmetry properties and by frozen phonon calculations, yielding mode frequencies and eigenvectors. This approach opens up a new field of surface chemistry analysis by dimer-vibration spectroscopy.

Journal Article↗
PubMed2002

Isolation of Nocardia paucivorans from the cerebrospinal fluid of a patient with relapse of cerebral nocardiosis.

Nocardia paucivorans represents a new species of the genus Nocardia that has recently been isolated from bronchial secretions of a patient with chronic lung disease. Here, we report on the course of a disseminated infection caused by this species: i.e., cerebral and subsequent meningeal manifestations, isolation from the cerebrospinal fluid, and in vitro susceptibility to various antimicrobial agents.

Brain Abscess↗
PubMed2002

Malignant intestinal non-Hodgkin's lymphoma from the surgical point of view.

BACKGROUND: Primary intestinal non-Hodgkin's lymphoma (I-NHL) is much less frequent than gastric lymphoma and has hardly been studied in prospective trails. To the surgeon, patients frequently present with abdominal emergencies. PATIENTS AND METHODS: A consecutive series of patients subjected to surgery because of I-NHL between 1998 and 1999 was evaluated retrospectively for characteristic clinical, radiographic and intraoperative findings. Patients with gastric lymphoma were not considered. RESULTS: 10 patients, 8 males and 2 females, with I-NHL were subjected to first-line surgery because of painful abdominal tumor, intestinal hemorrhage, obstruction or perforation. I-NHL was located most often in the small bowel (n = 7). It was rare in the colon (n = 2) and the duodenum (n = 1). Median postoperative follow-up was 28 months. Perioperative mortality was 10% (n = 1). Probability of survival 3 years after surgery was 60%. CONCLUSIONS: Patients with I-NHL frequently present with complications of tumor growth, requiring urgent surgical treatment. Irrespective of surgical complications we advocate surgery in cases of resectable disease as first-line treatment. Adjuvant treatment is indicated with respect to resection status and histopathological staging.

Adult↗
PubMed2001

Thirty-five year mortality following receipt of SV40- contaminated polio vaccine during the neonatal period.

Early poliovirus vaccines, both inactivated and live attenuated, were inadvertently contaminated with simian virus 40 (SV40), a monkey virus known to be oncogenic for newborn hamsters. Although large epidemiologic studies have not identified an elevated cancer risk in persons who received SV40-contaminated vaccines, fragments of SV40 DNA have recently been identified in certain human tumours. We report the follow-up of a cohort of 1073 persons, unique because they received SV40-contaminated poliovirus vaccines as newborns in 1961-63. A previous report of the status of these subjects as of 1977-79 identified 15 deaths, none due to cancer. The present study utilized the National Death Index to identify deaths in the cohort for the years 1979-96. Expected deaths were calculated from Cleveland area sex-, age-, race- and year-specific mortality rates. Increased mortality from all causes was not found. 4 deaths from cancer were found compared to 3.16 expected (P = 0.77). However, 2 deaths from testicular cancer occurred, compared to 0.05 expected (P = 0.002), which may be a chance finding due to multiple comparisons. There were 2 deaths due to leukaemia, a non-significant finding, and no deaths due to tumours of the types putatively associated with SV40. Although these results are, for the most part, consistent with other negative epidemiologic investigations of risks from SV40-contaminated vaccines, further study of testicular cancer may be warranted, and it will be important to continue monitoring this cohort which is now reaching middle-age.

Adult↗
PubMed2001

Infection of the skin caused by Corynebacterium ulcerans and mimicking classical cutaneous diphtheria.

Extrapharyngeal infections caused by Corynebacterium ulcerans have rarely been reported previously, and diphtheria toxin production has usually not been addressed. This case demonstrates that strains of C. ulcerans that produce diphtheria toxin can cause infections of the skin that completely mimic typical cutaneous diphtheria, thereby potentially providing a source of bacteria capable of causing life-threatening diseases in the patient's environment. Therefore, it is recommended to screen wound swabs for coryneform bacteria, identify all isolates, carefully assess possible toxin production, and send questionable strains to a specialist or a reference laboratory.

Aged↗