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J Fuchs

Publications and source records attributed to J Fuchs.

At least 19 recordsLinked to original sources
PubMed2006

Cervical atypical mycobacterial lymphadenitis in childhood: findings on sonography.

PURPOSE: To describe the sonographic appearance of cervical lymph nodes in twelve children with histopathologically confirmed atypical mycobacterial lymphadenitis. MATERIALS AND METHODS: Sonography of cervical lymph nodes was performed with a real-time linear scanner using a 13 MHz probe. Sonographic findings were retrospectively reviewed in 9 girls and 3 boys age 1.7 to 10.7 years (median age, 3.7 years), with cervical lymphadenopathy at initial presentation. RESULTS: Strong echoes within the lymph nodes were found in 4 (33 %) of the children, corresponding to calcifications on histopathological examination. Loss of regular nodal shape with circumscript polypoid spread of nodal masses into the subcutaneous tissue was found in 6 (50 %) patients; at least 1 of these 2 features was noted in 10 (83 %) of our 12 patients. At surgery, abscess formation was found in 8 (67 %) children. CONCLUSION: When nodal calcifications and spread of nodal masses into the subcutaneous tissue are found in patients with cervical lymphadenopathy, the examiner should maintain a high level of clinical suspicion for atypical mycobacterial lymphadenitis. Contrary to other causes of cervical lymphadenopathy, total surgical excision is the treatment of choice. Identification of these patients prior to surgery is therefore of utmost importance. Our data suggest that sonography could serve as an easy non-invasive method for this purpose.

Child↗
PubMed2006

Analytical model for ion acceleration by high-intensity laser pulses.

We present a general expression for the maximum ion energy observed in experiments with thin foils irradiated by high-intensity laser pulses. The analytical model is based on a radially confined surface charge set up by laser accelerated electrons on the target rear side. The only input parameters are the properties of the laser pulse and the target thickness. The predicted maximum ion energy and the optimal laser pulse duration are supported by dedicated experiments for a broad range of different ions.

Journal Article↗
PubMed2006

Transverse characteristics of short-pulse laser-produced ion beams: a study of the acceleration dynamics.

We report on first measurements of the transverse characteristics of laser-produced energetic ion beams in direct comparison to results for laser accelerated proton beams. The experiments show the same low emittance for ion beams as already found for protons. Additionally, we demonstrate that the divergence is influenced by the charge over mass ratio of the accelerated species. From these observations we deduced scaling laws for the divergence of ions as well as the temporal evolution of the ion source size.

Journal Article↗
PubMed2006

Measurements of UV-generated free radicals/reactive oxygen species (ROS) in skin.

Free radicals/reactive oxygen species (ROS) generated in skin by UV irradiation were measured by electron spin resonance (ESR). To increase the sensitivity of measurement the short life free radicals/ROS were scavenged and accumulated by using the nitroxyl probe 3-carboxy-2,2,5,5-tetrametylpyrrolidine-1-oxyl (PCA). The spatial distribution of free radicals/ROS measured in pig skin biopsies with ESR imaging after UV irradiation corresponds to the intensity decay of irradiance in the depth of the skin. The main part of free radicals/ROS were generated by UVA (320-400 nm) so that the spatial distribution of free radicals reaches up to the lower side of the dermis. In vivo measurements on human skin were performed with a L-band ESR spectrometer and a surface coil integrating the signal intensities from all skin layers to get a sufficient signal amplitude. Using this experimental arrangement the protection of UVB and UVA/B filter against the generation of free radicals/ROS in skin were measured. The protection against ROS and the repair of damages caused by them can be realized with active antioxidants characterized by a high antioxidative power (AP). The effect of UV filter and antioxidants corresponding to their protection against free radicals/ROS in skin generated by UVAB irradiation can be quantified by the new radical sun protection factor (RSF). The RSF indicates the increase of time for staying in the sun to generate the same number of free radicals/ROS in the skin like for the unprotected skin. Regarding the amount of generated free radicals/ROS in skin as an biophysical endpoint the RSF characterizes both the protection against UVB and UVA radiation.

Animals↗
PubMed2006

The national neonatal screening programme for congenital toxoplasmosis in Denmark: results from the initial four years, 1999-2002.

AIMS: To describe the outcome of four years' nationwide neonatal screening for congenital toxoplasmosis in liveborn newborns. METHODS: Congenital toxoplasmosis was diagnosed if specific Toxoplasma gondii IgM antibodies were detected in eluate from the PKU Guthrie filter paper card from a child. Infants diagnosed with congenital toxoplasmosis were examined for intracranial and retinal lesions and treated for three months with sulphadiazine, pyrimethamine, and folinic acid continuously. RESULTS: Eluates from PKU-cards from 262 912 newborns were analysed. The birth prevalence of congenital toxoplasma infection was 2.1 per 10 000 liveborns. Congenital toxoplasmosis was suspected in 96 infants and confirmed in 55. Forty seven children were examined for intracranial and retinal lesions soon after birth; 12 had clinical signs at this first examination. Of these, 5 had intracranial calcifications, 2 had retinochoroidal lesions, 4 had intracranial calcifications and retinochoroidal lesions, and 1 had hydrocephalus, intracranial calcifications, and retinochoroidal lesions. Ninety four eyes were examined soon after birth; there were central retinochoroidal lesions in 9. Two children had macular lesion of both eyes, five had macular lesions of one eye. At 1 year of age, 10/68 eyes had central lesions, and at 3 years of age, 5/32 had central lesions. Thus new retinochoroidal lesions developed in three eyes in the observation period. CONCLUSIONS: Neonatal screening is feasible for diagnosing children with congenital toxoplasmosis at birth in low endemic areas. Retinochoroiditis with macular lesion was diagnosed in 9.6% of the eyes at birth and in 15.6% of the eyes examined at 3 years of age.

Algorithms↗
PubMed2006

Analysis of German package inserts.

OBJECTIVE: Package inserts have an important impact on patients compliance and thus on the effectiveness of drug use. Despite efforts of the European or national regulatory authorities and manufacturers to improve the readability and comprehensiveness of package inserts, they are still the subject of critical discussion. MATERIAL AND METHODS: 68 German package inserts were chosen for a detailed analysis of their quality and suitability based on a set of 104 quality criteria developed prior to the survey. RESULTS: In many cases package inserts available on the German drug market did not include important information or were difficult to read or understand. In 73.5% of cases, the daily maximum dose was missing and 63.2% gave no information on the measures to take for each of the interactions. 66.2% of package inserts provided no instructions about the correct storage and 58.8% gave no instructions on the appropriate storage temperature. In 13 cases, dosage instructions were provided only in milligrams of active substance instead of a number of tablets or volume of liquid. 98.5% of the 68 package inserts included non-quantifiable statements such as "high dosage" or "take 2 - 4 tablets, 1 - 3 times daily". 97.1% contained repetitious information, 83.8% included advertising elements and 8.8% contained contradictory information. CONCLUSION: Package inserts must be optimized and tested by selected groups of patients prior to approval of the drug. This will avoid misunderstandings and lack of information and ensure that use of the drug will give the best possible outcome and avoid safety risks.

Comprehension↗
PubMed2005

Dynamics of electric fields driving the laser acceleration of multi-MeV protons.

The acceleration of multi-MeV protons from the rear surface of thin solid foils irradiated by an intense (approximately 10(18) W/cm2) and short (approximately 1.5 ps) laser pulse has been investigated using transverse proton probing. The structure of the electric field driving the expansion of the proton beam has been resolved with high spatial and temporal resolution. The main features of the experimental observations, namely, an initial intense sheath field and a late time field peaking at the beam front, are consistent with the results from particle-in-cell and fluid simulations of thin plasma expansion into a vacuum.

Journal Article↗
PubMed2005

Comparison of laser ion acceleration from the front and rear surfaces of thin foils.

The comparative efficiency and beam characteristics of high-energy ions generated by high-intensity short-pulse lasers (approximately 1-6 x 10(19) W/cm2) from both the front and rear surfaces of thin metal foils have been measured under identical conditions. Using direct beam measurements and nuclear activation techniques, we find that rear-surface acceleration produces higher energy particles with smaller divergence and a higher efficiency than front-surface acceleration. Our observations are well reproduced by realistic particle-in-cell simulations, and we predict optimal criteria for future applications.

Journal Article↗
PubMed2005

[Uncorrected transposition of the great arteries and large ventricular septum defect perioperative management of a caesarean section].

Patients with congenital cyanotic heart disease are a challenge to the anaesthetist due to the individual haemodynamic characteristics. Maintaining a balance between systemic and pulmonary-vascular resistance is crucial. Here we outline the successful perioperative management of a 24-year-old female with uncorrected transposition of the great arteries (D-TGA) and large septal defect of the ventricle (functionally single ventricle). She was transferred to our perinatologic centre in the 32nd week of pregnancy with symptoms of increasing cardial insufficiency. The peripartum management was agreed upon at an interdisciplinary conference and caesarean section was performed in the 35th week of pregnancy with epidural anaesthesia and no significant problems. Due to hypercoagulability and the risk of "paradoxical" embolism, low molecular weight heparin was given for 6 weeks post partum. The infant was underweight and was admitted to the neonatal intensive care unit, where she made a satisfactory progress.

Adult↗
PubMed2005

[Vasopressin].

Explore the source record for details and available documents.

Abdomen, Acute↗
PubMed2005

[Deficits and outlook on gender-specific health care as exemplified by KHK and mental disorders].

Gender differences in health care are controversially discussed. Results show superfluous, insufficient or inappropriate health care of female and male patients. Many publications show that women are not sufficiently included in clinical trials and therefore data are not useful for analysing gender differences. Survey data like the German National Health Interview and Examination Survey 1998 (Bundes-Gesundheits survey 1998) can be used alternatively to analyse gender specific issues. This survey was used to show possible age and gender differences in prevalence, drug usage and health counselling of female and male patients with coronary heart disease and mental disorders. The number of physician attendances differs in sex and age group in both groups of illnesses. Women have higher number of physician consultations than men and the elderly more than the younger persons. For elderly women with coronary heart disease the control of blood cholesterol levels seems to be poorer than in men. Men get more health counselling from their doctors than women. The results emphasize the importance of considering gender differences in medical research.

Clinical Trials as Topic↗
PubMed2005

[An example for a practice-oriented curriculum in social medicine under conditions of the new medical licensing regulations. Experiences with practiced-oriented teaching and possibilities for including practical issues in the teaching syllabus of medicine after the introduction of new medical licensing regulations].

Experience with teaching medical students the subject of Social Medicine shows that their interest can be greatly improved by including practical issues such as interviewing chronically ill patients at home, or visiting patient counselling services in the community. With the introduction of the new licensing regulations for physicians, there will be only one final examination and the medical faculties will now have to conduct the examinations themselves. In order to create legal confidence in the results, sufficient homogeneity of the teaching syllabus in Vocational and Social Medicine courses as well as in the new Health Economics courses must be assured for all students. The merger of the two medical faculties of the Free University and the Humboldt University in Berlin have increased student numbers to 400 per semester, so that 20 groups will have to be taught simultaneously. This situation makes excursions to patients or to community facilities nearly impossible. Potential alternatives to allow inclusion of practical issues in the course, even under the new circumstances, are the use of problem-based learning techniques (PBL) such as the creation of theoretical cases dealing with special problems of Social Medicine or the use of standardised patients.

Education, Medical↗
PubMed2005

HIV vaccine efficacy trial participation: men who have sex with men's experiences of risk reduction counselling and perceptions of risk behaviour change.

Qualitative interviews were conducted with 35 men who have sex with men, enrolled in the world's first phase III HIV vaccine efficacy trial at five US sites, regarding their risk reduction counselling experiences and their perceptions of its impact on risk behaviour. Respondents ranged in age from 20 to 58 years and were predominately white (71.4%) in racial/ethnic origin. Systematic qualitative analysis revealed that a positive counselling experience meant having good rapport with clinic staff. Differences in attitudes toward counselling were related to either a personal approach of balancing an enjoyable sex life with safe sex behaviours (balancing risks) or accepting the consequences of risky sexual behaviour rather than making changes (risk homeostasis). Respondents seeking to balance risks indicated that they saw themselves engaging in safer sexual behaviour almost twice as often as in riskier behaviours. They perceived counselling and behavioural risk assessments to help increase their awareness of personal risk-taking behaviours. Conversely, those with a risk homeostasis approach reported that they had established sexual boundaries prior to trial participation that had thus far proven to be effective in avoiding HIV infection, and that they were comfortable with the level of risk taken. Thus, risk reduction counselling had little to no influence on their sexual practices. Some of these men also indicated that while they had not found the risk reduction information imparted to them by clinic staff to be novel, counselling was beneficial in reinforcing their HIV/AIDS and safe sex knowledge base.

AIDS Vaccines↗
PubMed2005

The influence of the Univent endotracheal tube on internal jugular vein cannulation.

This prospective clinical investigation assessed the effect of placement of a Univent tube on the anatomy of the internal jugular veins and the success of cannulation of the left internal jugular vein. After obtaining informed consent, 48 adult patients were enrolled. Of these, 42 patients were eligible and were divided into two groups: Univent tube (group U, n=21) and wire enforced endotracheal tube (group C, n=21). The Univent tube group were having a left thoracotomy. Using horizontal ultrasound scans just above the thyroid gland, the internal jugular vein was visualized and measured before and after Univent placement. The number of needle passes necessary to cannulate the left internal jugular vein in the two groups was also compared. Univent tubes were associated with lateral displacement of the right carotid artery and internal jugular vein on the convex side of the Univent tube, with compression of the right internal jugular vein by the artery, resulting in a kidney-shaped cross-section of the vein. On the left (concave side of the tube), the neck was indented, the sheath of the left carotid artery was displaced medially, and the left internal jugular vein distorted to an ellipse. There was a significant increase in the lateral diameter and a decrease in the cross-sectional area of the left internal jugular vein (t-test, P < 0.05). The first attempt at cannulation of the left internal jugular vein failed significantly more often in the Univent group (13/21 vs 5/21 in group C, Chi-square 6.22, P=0.025). Cannulation of the internal jugular vein before placement of the Univent tube, or placement with ultrasound guidance is suggested.

Carotid Arteries↗
PubMed2004

Plasma devices to guide and collimate a high density of MeV electrons.

The development of ultra-intense lasers has facilitated new studies in laboratory astrophysics and high-density nuclear science, including laser fusion. Such research relies on the efficient generation of enormous numbers of high-energy charged particles. For example, laser-matter interactions at petawatt (10(15) W) power levels can create pulses of MeV electrons with current densities as large as 10(12) A cm(-2). However, the divergence of these particle beams usually reduces the current density to a few times 10(6) A cm(-2) at distances of the order of centimetres from the source. The invention of devices that can direct such intense, pulsed energetic beams will revolutionize their applications. Here we report high-conductivity devices consisting of transient plasmas that increase the energy density of MeV electrons generated in laser-matter interactions by more than one order of magnitude. A plasma fibre created on a hollow-cone target guides and collimates electrons in a manner akin to the control of light by an optical fibre and collimator. Such plasma devices hold promise for applications using high energy-density particles and should trigger growth in charged particle optics.

Journal Article↗
PubMed2004

Repetition rate increase and diffraction-limited focal spots for a nonthermal-equilibrium 100-TW Nd:glass laser chain by use of adaptive optics.

Dynamic wave-front correction is applied before each shot on a 100-TW, 30-J/300-fs high-power laser facility by use of an adaptive-optics system. This system allows us to increase the repetition rate of high-energy lasers while maintaining excellent and constant beam focusability with a Strehl ratio of >0.75 despite the amplifiers' not being in thermal equilibrium. The best results in terms of the highest Strehl ratio and intensities are obtained when locking the system on wave-front sensing after pulse recompression.

Journal Article↗
PubMed2004

Ultralow emittance, multi-MeV proton beams from a laser virtual-cathode plasma accelerator.

The laminarity of high-current multi-MeV proton beams produced by irradiating thin metallic foils with ultraintense lasers has been measured. For proton energies >10 MeV, the transverse and longitudinal emittance are, respectively, <0.004 mm mrad and <10(-4) eV s, i.e., at least 100-fold and may be as much as 10(4)-fold better than conventional accelerator beams. The fast acceleration being electrostatic from an initially cold surface, only collisions with the accelerating fast electrons appear to limit the beam laminarity. The ion beam source size is measured to be <15 microm (FWHM) for proton energies >10 MeV.

Journal Article↗