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Biomedical subjects

J Fuchs

Publications and source records attributed to J Fuchs.

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

[Influence of environmental polluting ozone on the the skin].

The skin is directly and frequently exposed to a pro-oxidative environment, including ozone and UV-radiation. While ozone in the stratosphere protects against mutagenic UVC-radiation, it is also a major air pollutant in urban areas. With its strong oxidizing potential, ozone is perhaps one of the most reactive chemicals the skin ever encounters. Although a large body of evidence exists for ozone- induced oxidative stress in the respiratory tract, the current knowledge on its in vivo effect on cutaneous tissues is based on studies of the last 10 years. Acute ozone exposure damages the stratum corneum, depletes skin vitamin C and E and induces lipid and protein oxidation in upper epidermal layers. Secondary products penetrate into deeper skin layers and are capable of activating signal transduction pathways and inducing cell damage. It has been shown in a murine model, that environmentally relevant ozone concentrations can induce a stress response in the skin.

Air Pollutants↗
PubMed2004

ECG-guided central venous catheter positioning: does it detect the pericardial reflection rather than the right atrium?

BACKGROUND AND OBJECTIVE: Although electrocardiography (ECG) guidance of central venous catheters (CVCs) is traditionally thought to detect the entrance into the right atrium (RA), there is little evidence in the literature to confirm this. We previously observed a high incidence of left-sided CVCs abutting the wall of the superior vena cava (SVC), even when the catheters were advanced past the point of increased P-wave amplitude. Our hypothesis was that this ECG amplitude signal is actually detecting the pericardial reflection rather than the RA. The goal of the study was to position catheter tips under ECG guidance outside the RA. METHODS: One-hundred central venous triple-lumen catheters inserted either via the right or the left internal jugular veins, respectively, were analysed in cardiac surgical patients. The position of the catheter tip was ascertained by ECG. METHOD A: A Seldinger guide-wire in the distal lumen served as exploring electrode, the respective insertion depth was recorded. METHOD B: The middle lumen (port opening 2.5 cm from the catheter tip, thus the catheter was advanced more towards the atrium) filled with a saline 10% fluid column served as the exploring electrode, and the insertion depth was recorded again. Descriptive data are given as mean+/-standard deviation. RESULTS: On average, the catheters were advanced by the expected 2+/-0.3 cm using Method B beyond the initial insertion by Method A. All 100 CVCs were finally correctly positioned in the SVC and confirmed by transoesophageal echocardiography. When chest radiography was performed after surgery not a single catheter abutted the lateral wall of the SVC. CONCLUSION: Since both methods detected the same structure, and catheters placed by Method B did not result in intra-atrial CVC tip position, the first increase in P-wave amplitude does correspond to a structure in the SVC, most likely the pericardial reflection.

Aged↗
PubMed2004

[Duration of untreated psychosis (DUP): an useful predictor of outcome in schizophrenia?].

UNLABELLED: The concept of DUP has gained much interest as a possible predictor of outcome variables. The review of the current state of research suggests that DUP may be related to remission, social functioning and severity level of symptomatology. In the present retrospective-prospective study 50 first-time admitted patients were interviewed with the "Interview for the Retrospective Assessment of the Onset of Schizophrenia" (IRAOS). Outcome was measured after six months and one year with the "Positive and Negative-Syndrom Scale" (PANSS) and the "Disability Assessment Schedule" (DAS). Patients with long DUP had a worse outcome regarding the severity level of positive symptoms, of general symptoms and social disability. Corresponding well with some other studies, there was no association between DUP and negative symptoms. CONCLUSION: DUP can be regarded as an useful predictor of outcome in schizophrenia. However, further research is required to confirm these results in long-term studies.

Adolescent↗
PubMed2004

Hypoxia-induced long-term increase of dopamine and tyrosine hydroxylase mRNA levels.

The aim of the present study was to determine hypoxia-induced changes in the long-term expression of tyrosine hydroxylase (TH) mRNA and the steady-state dopamine (DA) levels in rat mesencephalic cell cultures. The cultures were exposed to hypoxia during the early developmental period, and DA content and TH mRNA expression were determined on day in vitro (DIV) 14. Hypoxic exposure of 5-day-old cultures resulted in increased DA (control 89.9+/-8.9, hypoxia 135.8+/-23.7 pg/microg protein) and TH mRNA (control 37.3+/-4.7, hypoxia 143.1+/-49.4 pg/microg RNA) levels. To analyze the involvement of hypoxia-inducible factor-1 (HIF-1) in these changes, we studied its activation using reporter gene. Hypoxia caused a 3-fold increase in HIF-1 activity. Our data suggest that hypoxia/ischemia during the putative critical developmental period of neurons may determine the tyrosine hydroxylase gene expression and, consequently, the development of the dopaminergic system.

Animals↗
PubMed2003

Spatial uniformity of laser-accelerated ultrahigh-current MeV electron propagation in metals and insulators.

The evolution of laser-generated MeV, MA electron beams propagating through conductors and insulators has been studied by comparing measurement and modeling of the distribution of MeV protons that are sheath accelerated by the propagated electrons. We find that electron flow through metals is uniform and can be laser imprinted, whereas propagation through insulators induces spatial disruption of the fast electrons. Agreement is found with material dependent modeling.

Journal Article↗
PubMed2003

Observation of ion acoustic waves associated with plasma-induced incoherence of laser beams using Thomson scattering.

We have carried out experiments to investigate the physical processes responsible for the recently discovered phenomenon of plasma-induced incoherence (PII) of a laser beam. Using a Thomson scattering diagnostic, we have observed ion acoustic waves (IAW) having wave vectors transverse to the interaction beam spectral and temporal characteristics of which show a clear correlation with other signatures of PII for various conditions of plasma density and laser intensity. These results support the recent theoretical interpretation for which the IAW result from the coupling between forward stimulated Brillouin scattering and self-focusing of the laser light in PII mechanisms.

Journal Article↗
PubMed2003

UV-induced free radicals in the skin detected by ESR spectroscopy and imaging using nitroxides.

Reactive free radicals and reactive oxygen species (ROS) induced by ultraviolet irradiation in human skin are strongly involved in the occurrence of skin damages like aging and cancer. In the present work an ex vivo method for the detection of free radicals/ROS in human skin biopsies during UV irradiation is presented. This method is based on the Electron Spin Resonance (ESR) spectroscopy and imaging and uses the radical trapping properties of nitroxides. The nitroxides 2,2,6,6-Tetramethylpiperidine-1-oxyl (TEMPO), 3-Carbamoyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl (PCM), and 3-Carboxy-2,2,5,5-tetramethylpyrrolidine-1-oxyl (PCA), were investigated for their applicability of trapping reactive free radicals and reactive oxygen species in skin during UV irradiation. As a result of the trapping process the nitroxides were reduced to the EPR silent hydroxylamins. The reduction rate of TEMPO was due to both the UV radiation and the enzymatic activity of the skin. The nitroxides PCM and PCA are sufficiently stable in the skin and are solely reduced by UV-generated free radicals/ROS. The nitroxide PCA was used for imaging the spatial distribution of UV-generated free radicals/ROS. As a result of the homogeneous distribution of PCA in the skin, it was possible to estimate the penetration of UVA and UVB irradiation: The UV irradiation decreased the PCA intensity corresponding to its irradiance and penetration into the skin. This reduction was shown to be caused mainly by UVA radiation (320-400 nm).

Biopsy↗
PubMed2003

Interventional treatment of infantile hepatic hemangioendothelioma.

BACKGROUND/PURPOSE: Hemangioendothelioma is the most frequent liver tumor in infancy. Untreated symptomatic patients with heart failure have a high mortality rate. Symptomatic forms may request nonoperative treatment, because surgery is burdened with high risks in patients with heart failure. The authors report their experience with interventional coil occlusion of infantile hepatic hemangioendothelioma (IHE). METHODS: Four patients (age range, 2 to 146 days; mean, 53 days) suffering from IHE associated with heart failure were treated by endovascular coil occlusion of arterial feeders. Catheter intervention was performed via an arterial (n = 2) or venous (n = 2) approach. RESULTS: Signs of heart failure resolved within 2 to 8 days after occlusion in 3 patients. Tumor regression could be observed sonographically within 4 weeks postinterventionally. In 3 children, tumor size was reduced from a mean of 544 mL (65 to 1,350) to a mean of 4 mL (2 to 6); Mean systolic peak velocity in the hepatic artery was decreased from 170 cm/s (140 to 200) before occlusion to 45 cm/s (36 to 70) during follow-up. In the fourth patient, endovascular intervention could not control a rapidly progressing hemangioendotheliomatosis, and finally a liver transplantation had to be performed. CONCLUSIONS: Interventional occlusion of feeding arteries in symptomatic IHE is a safe and effective alternative to early open surgery. The efficacy of endovascular intervention in multifocal tumors seems questionable.

Blood Flow Velocity↗
PubMed2003

Intra-atrial ECG is not a reliable method for positioning left internal jugular vein catheters.

BACKGROUND: ECG guidance is widely used for positioning central venous catheters (CVCs) in the superior vena cava. We noticed a higher incidence of a more perpendicular angle between the catheter tip and the vessel wall after left-sided ECG-guided catheter positioning. To investigate the value of left-sided ECG guidance, we performed this prospective study. METHODS: Of 114 patients, 53 were randomized to right and 61 to left internal jugular vein catheterization using a triple lumen catheter. Three methods to ascertain catheter tip position were sequentially applied in each patient, and the insertion depths (ID) obtained using each of the three methods were recorded: (i). ECG guidance with a Seldinger guide wire (ID-A); (ii). ECG guidance with saline 10% used as an exploring electrode (ID-B); (iii). from position ID-B, the catheter was rotated and advanced until all three lumina could be aspirated easily. The catheter was fixed in that position (ID-C). To determine final catheter tip position, intraoperative transoesophageal echocardiography (TOE) and a postoperative chest X-ray (CXR) were performed. RESULTS: The depth of insertion of a catheter using the three methods varied significantly in left-sided (P<0.001), but not in right-sided catheters. Forty-eight of 57 (84%) left-sided CVCs, correctly positioned according to ECG guidance, had to be advanced further to achieve free aspiration through all three lumina. By this stage, five of the catheter tips had been positioned in the upper right atrium as demonstrated by TOE. There were 13 malpositions (23%) after left-sided insertion. In nine catheter malpositions, undetected by ECG guidance, the angle between the catheter tip and the lateral wall of the superior vena cava exceeded 40 degrees on CXR. CONCLUSIONS: Intra-atrial ECG does not detect the junction between the superior vena cava and right atrium. It is not a reliable method for confirming position of left-sided CVCs. Post-procedural CXRs are recommended for left-sided, but not right-sided CVCs.

Aged↗
PubMed2002

Multibeam stimulated brillouin scattering from hot, solid-target plasmas.

We report on multibeam, laser-plasma interaction experiments in plasmas relevant to future direct-drive-ignition experiments. Six interaction beams are incident on preformed plasmas containing critical density. Stimulated Brillouin scattering (SBS) shows strong evidence of electromagnetic wave seeding of side- and backscattering. The data are also consistent with shared ion waves driven by the six symmetrically arranged interaction beams. Early SBS quenching is observed and attributed to the hydrodynamics of the plasma.

Journal Article↗
PubMed2002

MeV ion jets from short-pulse-laser interaction with thin foils.

Collimated jets of carbon and fluorine ions up to 5 MeV/nucleon ( approximately 100 MeV) are observed from the rear surface of thin foils irradiated with laser intensities of up to 5 x 10 (19)W/cm(2). The normally dominant proton acceleration could be surpressed by removing the hydrocarbon contaminants by resistive heating. This inhibits screening effects and permits effective energy transfer and acceleration of other ion species. The acceleration dynamics and the spatiotemporal distributions of the accelerating E fields at the rear surface of the target are inferred from the detailed spectra.

Journal Article↗
PubMed2002

Langmuir decay instability cascade in laser-plasma experiments.

Thomson scattering has been used to investigate the nonlinear evolution of electron plasma waves (EPWs) generated by stimulated Raman scattering (SRS). Two complementary diagnostics demonstrate the occurrence of the cascade of Langmuir decay instabilities (LDI). The EPW wave-number spectrum displays an asymmetric broadening towards small wave numbers, interpreted as a signature of the secondary EPWs produced in the LDI cascade. The number of cascade steps is in agreement with the broadening of the associated ion-acoustic-waves' spectra. The total energy transferred in the EPWs cascade is found to be either less than or of the same order of magnitude as the energy of the primary EPW.

Journal Article↗
PubMed2002

Reduction of the coherence time of an intense laser pulse propagating through a plasma.

We present direct measurements of the coherence time of a laser beam after propagation through an underdense plasma. At an intensity of 10(14) W/cm(2), a large decrease of the coherence time is observed, from 300 ps to a few picoseconds. This decrease is larger as the plasma density is increased or as the light is scattered at larger angles. The amount of temporal decorrelation as well as the effect of the plasma density, laser intensity, and scattering angle all coincide with trends observed in recent numerical simulations.

Journal Article↗
PubMed2002

Impact of magnetic resonance urography on preoperative diagnostic workup in children affected by hydronephrosis: should IVU be replaced?

PURPOSE: The aim of this study was to determine the role of magnetic resonance urography (MRU) in preoperative diagnostic workup of children with hydronephrosis in a prospective clinical study with comparison of MRU, standard diagnostic investigations, and intraoperative findings. METHODS: Thirty-one children with hydronephrosis secondary to different causes underwent ultrasound scan (US), intravenous urography (IVU), micturation cysto-urethrography (MCU), isotope nephrography (ING) and MRU. For MRU the authors performed sagittal and coronal halve-Fourier SSFSE scans in a 1.5 Tesla MR system. T1- and T2-weighted sequences were used in axial orientation to improve morphologic information. In 24 patients, preoperative data were compared with intraoperative findings. RESULTS: Comparison of the different imaging modalities proved MRU to be able to provide more detailed information about the correct localization of stenoses along the urinary tract and the morphology of renal parenchyma. MRU showed the highest concordance of all imaging modalities with intraoperative findings. CONCLUSION: As a reliable investigation, MRU has the potentials to replace IVU in preoperative diagnostic workup of hydronephrosis in childhood.

Adolescent↗
PubMed2002

[Pathways to psychiatric care and duration of untreated psychosis in first-episode psychosis patients].

To reduce the time of untreated psychosis it is necessary to know the patients' pathways to psychiatric care. For this reason we interviewed 50 first-episode patients with the Interview for the Retrospective Assessment of the Onset of Schizophrenia (IRAOS) for information about duration of untreated psychosis (DUP) and about their help-seeking contacts before psychiatric admission. In contrast to other findings of long DUP, 50 % of our patients were admitted after 8 weeks (median) of untreated positive symptoms. The mean value of 62 weeks corresponds well with results of other studies. There were important differences in DUP depending on which kind of statistical parameter (median or mean) was used. Contrary to studies from other countries only 24 % of our patients had their first contact with a general practitioner. Between patients with short (< 1 year) and long (> 1 year) DUP no significant differences were found in contacts with helpers and in the duration from the first contact until psychiatric admission. However, patients with long DUP made their first contact with helpers significantly later after the beginning of positive symptoms than patients with short DUP.

Adolescent↗
PubMed2002

[Gender-sensitive public health publications in Germany? Results of a review of literature].

BACKGROUND: The project 'Gender Bias - Gender Research' investigates how far gender issues are considered in German-language Public Health journals. Target is the analysis of the publication practice in Public Health in order to point out status, deficits and perspectives of gender-specific research. METHODS: We developed a standardised evaluation instrument, which covers the semantic, methodical-technical and contentual area regarding gender issues and evaluated all original contributions of the years 1990, 1995 and 1999 in the journals 'Das Gesundheitswesen', 'Sozial- und Präventivmedizin' and 'Zeitschrift für Gesundheitswissenschaften'. 268 (of 517) contributions applied to persons (in contrast to i. e. programmes, institutions) and were completely analysed. RESULTS: The main part of the contributions take women and men into account, but do not consider them continuously in all parts of the research process and in this way do not fulfil all requirements for gender-sensitive research. Gender finds most consideration on the semantic level. Less than half of the authors consider the different situation of women and men in the formulation in hypotheses, sampling, or data analysis, and only 35 % of them make reference to this in their conclusions. We found differences between the examined journals and years. CONCLUSIONS: The concerns of women and men should be considered at all levels of research. Attention should be paid to this when writing, reviewing and publishing contributions.

Female↗
PubMed2002

Cystic echinococcosis with perforation into the biliary tract in an eight-year-old girl.

Cystic echinococcosis (CE) is a zoonotic infection caused by echinococcus granulosus and is still frequent in endemic areas. CE is predominantly localised in the liver. The therapy of choice is the surgical sanitation of the lesions, increasingly through interventional procedures such as percutaneous punctation of the cysts, aspiration of the cystic fluid, instillation of a protoscolicidal solution and reaspiration of this solution (PAIR). However, in some cases, such as perforation into the biliary tract, PAIR is not feasible. We report on an eight-year-old girl who suffered from CE with perforation of one cyst into the biliary tract. The diagnosis was confirmed by ERCP and cholangioscopy and a right hemihepatectomy was performed. The girl received adjuvant chemotherapy with albendazol perioperatively and is still asymptomatic with no indications of disease 10 months after the operation.

Albendazole↗