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Biomedical subjects

W Hoffmann

Publications and source records attributed to W Hoffmann.

337 records · Page 19Linked to original sources
PubMedDate not supplied

[Determination of systolic time intervals in healthy and in adriamycin-treated children].

The systolic time intervals have been measured in 212 normal children, aged 3 to 16 years, and in 30 children with malignant tumours, who were treated with Adriamycin. The normal values of STI in children were calculated and evaluated. Nomogramms for Left Ventricular Ejection Time (LVET) and Pre-ejection Period (PEP) are presented to permit rapid estimation of predicted normal values in children. The evaluation of 5 consecutive heart cycles is enough for measuring STI. Statistically no significant differences were found not only between STI in girls and boys but also between STI-values measuring in the morning, at noon or in the afternoon. Adriamycin-cardiomyopathy can be detected early and reliable through the estimation of the STI.

Adolescent↗
PubMedDate not supplied

[Ventricular tachycardia after erythromycin administration in a newborn with congenital AV-block].

UNLABELLED: This report is on a newborn with congenital complete av-block due to a maternal collagenosis. The intravenous application of erythromycin produced premature ventricular beats and non sustained ventricular tachycardias by prolongation of the QT interval. After discontinuation of the erythromycin application, the QT-interval normalised. CONCLUSION: In atrioventricular conduction disorders with severe bradycardia and prolongation of the QT interval, the application of erythromycin--if unavoidable--should be managed by slow intravenous infusion and with permanent ECG monitoring.

Anti-Bacterial Agents↗
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Fallout from the Chernobyl nuclear disaster and congenital malformations in Europe.

Investigators estimate that the population exposure that resulted from the Chernobyl fallout is in the range of natural background radiation for most European countries. Given current radiobiologic knowledge, health effects-if any-would not be measurable with epidemiologic tools. In several independent reports, however, researchers have described isolated peaks in the prevalence of congenital malformations in the cohort conceived immediately after onset of the fallout. The consistency of the time pattern and the specific types of malformation raise concern about their significance. In this study, the author summarizes findings from Turkey, Belarus, Croatia, Finland, Germany, and other countries, and implications for radiation protection and public health issues are discussed.

Abnormalities, Radiation-Induced↗
PubMedDate not supplied

A cluster of childhood leukemia near a nuclear reactor in northern Germany.

Between February 1990 and December 1995, professionals diagnosed six cases of childhood leukemia among residents of the small rural community of Elbmarsch in northern Germany. Five of these cases were diagnosed in only a 16-mo period between February 1990 and May 1991. All cases lived in close proximity (i.e., 500-4,500 m) to Germany's largest capacity nuclear boiling-water reactor. We calculated standardized incidence ratios and exact 95% confidence intervals for a 5-km-radius circular area around the plant. The standardized incidence ratio for the time period 1990-1995 was 460 (95% confidence interval: 210, 1,030). The analysis was restricted further to the years 1990 and 1991, and the standardized incidence ratio increased to 1,180 (95% confidence interval: 490, 2,830). Presently, this cluster of childhood leukemia cases cannot be explained in terms of established and putative risk factors--including radiation from medical sources--for childhood leukemia.

Acute Disease↗
PubMedDate not supplied

Performance and use of current sheet antennae for RF-hyperthermia of a phantom monitored by 3 tesla MR-thermography.

Several MR-compatible current sheet antennae (CSA) of different height (h) (16 cm (l) x 8 cm (w) x 1-5 cm (h)) were built for simulated RF (96 MHz) hyperthermia of a medium-sized (12l) tissue-equivalent phantom inside a 3 tesla whole body tomograph. Prior to use, efficiencies of the CSA were determined by network analysis and by calorimetry. Depending on the height h of the CSA and on the thickness d(bolus) of the water bolus used for RF-coupling of the CSA to the lossy medium, their efficiency varied between 20-70% and the CSA with h = 3 cm was selected for simulated RF hyperthermia. During heating, spatial temperature distributions (20-42 degrees C) of five slices (voxel size 2 x 2 x 10mm(3)) were recorded intermittently within 4 s/slice by measuring the temperature dependent shift of the (1)H resonance frequency (125.32 MHz). A phased array consisting of two identical CSA produced distinctly different spatial temperature distributions at 0 and 180 degrees phase difference between both RF channels feeding the antennae. Within a one-dimensional heat diffusion model, the specific absorption rate (SAR) of the electromagnetic wave generated by a single antenna was deduced from the experimental data resulting in a penetration depth (1/e(2)) of approximately 4 cm.

Biophysical Phenomena↗
PubMedDate not supplied

Molecular analysis of the ependymin gene and functional test of its promoter region by transient expression in Brachydanio rerio.

Ependymins are secretory products of meningeal cells and represent the predominant glycoproteins in the cerebrospinal fluid from various orders of teleost fish. In the zebrafish, their expression starts between 48 and 72 h post-fertilization. Generally, they share characteristics with proteins involved in cell-contact phenomena. Here, we characterize the ependymin gene from Brachydanio rerio and its flanking regions. The sequence was obtained from clones generated using the polymerase chain reaction (PCR), including a variation of an "anchored" PCR. Also, clones from a conventional phage library were analyzed. We found that the transcribed portion is arranged in six exons. Transient expression of an ependymin-promoter-lacZ gene fusion in zebrafish embryos revealed that the 2.0-kb upstream regulatory region used is sufficient to direct the ependymin-specific correct temporal and spatial expression pattern of the lacZ reporter gene.

Amino Acid Sequence↗
PubMedDate not supplied

Biomarker monitoring for health risk based on sensitivity to environmental mutagens.

Ongoing human and environmental genome programs have generated a tremendous amount of information regarding the genetic basis for human disease. The information can be used to enhance existing bioassays, as well as to develop new bioassays for improving human monitoring with the goal of disease prevention. In this review, some biomarkers that can be used for the purpose are presented, with an emphasis on using biomarkers to monitor human sensitivity to environmental mutagens. The application of biomarkers in clarifying the role of inherited and acquired susceptibility for developing environmental disease will be discussed. We emphasize the use of biomarkers that can detect mutagen sensitivity and DNA repair deficiency in the humans as an indication of susceptibility to disease. Such sensitivity can be either genetically determined or acquired from the exposure to environmental mutagens.

Biological Assay↗
PubMedDate not supplied

Cancer risk from low-level ionizing radiation: the role of age at exposure.

This article examines methodological issues related to epidemiologic investigations of the influence of age at exposure on radiation risk estimates; the epidemiologic literature on the role of age at exposure in radiation-cancer associations; and biological mechanisms that may account for associations observed in these studies. There is substantial evidence that young children, and especially the fetus, are highly vulnerable to ionizing radiation. Investigations also suggest that sensitivity may increase at the oldest ages of exposure. Further attention to modifying factors in radiation-cancer associations, such as age at exposure, may help to protect workers and the public by improving our understanding of sensitivity variation within populations.

Age Factors↗
PubMedDate not supplied

Endoscopic lithotripsy of bile duct stones using a new laser with automatic stone recognition.

Biliary stones can be removed in 85% to 90% of patients using endoscopic sphincterotomy; in the rest alternative methods are required. Thirty-eight consecutive patients in whom conventional methods had failed underwent laser lithotripsy with a new laser system. A flashlamp-pumped pulsed laser with rhodamine 6G as dye (594 nm) has a tissue-stone recognition system that can identify bile duct stones by analyzing backscattered light and interrupt the pulse in case of tissue contact (Lithognost, Telemit, Munich, Germany). Access of the 0.25- or 0.30-mm-diameter laser fiber to the stones was achieved perorally in 18 patients. In 13 of these cases, eccentrically located stones in the middle or proximal common bile duct were targeted with a 3.4-mm miniscope introduced through a standard duodenoscope. Fluoroscopically guided peroral lithotripsy was performed in 5 patients with stones in the distal common bile duct that could be approached with a standard ERCP catheter. Percutaneous cholangioscopic laser lithotripsy was carried out in 20 patients with stones not amenable to retrograde techniques. The mean number of bile duct stones per patient was 3.6, and the average diameter of the largest stone of each patient was 25 mm (range, 8 to 52 mm). The bile ducts were cleared in all but 1 patient in a mean number of 1.3 sessions lasting 15 to 115 minutes (mean, 60). No laser-related complications were observed. The Lithognost laser was successfully used in 37 of 38 patients referred for the removal of difficult bile duct stones.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗