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Biomedical subjects

P Brunner

Publications and source records attributed to P Brunner.

At least 19 recordsLinked to original sources

Increased radon concentrations in classrooms used for pottery workshops.

In a pilot study of nine schools the radon (Rn) concentrations were measured systematically. The mean radon concentrations in the classrooms on the ground-floor and on higher floors was 52 Bq/m3, which is equivalent to the mean values in Central Europe. Several of the basement rooms used for handicraft lessons had significantly increased Rn levels with a mean concentration of 617 Bq/m3. In all other parts of the basement Rn levels were clearly lower with a mean concentration of 136 Bq/m3. In the rooms used for handicraft lessons numerous articles of pottery were on display. After removing these the Rn in air concentration was reduced to a mean value of 83 Bq/m3.

Air Pollution, Indoor

[Adherence of pacemaker electrodes to the endomyocardium--a postmortem study].

The weight of extraction of a pacemaker electrode from the endomyocardium was evaluated in 29 hearts (31 pacemakers). The maximum weight of extraction was 2375 g, the mean being 760 g. The weight of extraction depends on the duration of the implantation of the pacemaker, and on the thickness of the right ventricle, but there is no relationship to the shape of the pacemaker electrode, nor to the site of insertion in the right ventricular endomyocardium. In half the cases, pieces of endomyocardium adhered to the extracted electrode, the largest piece being 5 cm x 0.5 cm x 0.5 cm. The epicardium was not injured in any of these cases. It was often noticed that scarred adhesions existed between the cable of the pacemaker and the endocardium and/or the intima of the blood vessels. During traction in vivo, strangulation of the right heart and the blood vessels may occur.

Aged

Beneficial effect of liposome-encapsulated muramyl tripeptide in experimental septicemia in a porcine model.

In a porcine model of pneumococcal septicemia, animals were pretreated with 1 mg of liposome-encapsulated muramyl tripeptide phosphatidylethanolamine (MTP-PE) or with liposomes alone. After 24 h each animal received an injection of either 10(9) or 10(10) pneumococcal serotype 6B cells. MTP-PE pretreatment resulted in less pronounced leukocytopenia, with a nadir of 6,700 (versus 4,100) leukocytes per mm3 after injection of 10(9) bacteria and a nadir of 4,400 (versus 3,800) leukocytes per mm3 after injection of 10(10) bacteria. At the same time bacterial clearance was substantially improved by MTP-PE pretreatment. Finally, pretreatment with MTP-PE dramatically reduced mortality; the average death rates for both series of animals used were 55% for liposome-pretreated animals and 3% for animals pretreated with MTP-PE-containing liposomes. These results in a preclinical model suggest that treatment with MTP-PE-containing liposomes might be beneficial in controlling septicemia in patients at risk.

Acetylmuramyl-Alanyl-Isoglutamine

Chernobyl fallout on Alpine glaciers.

Measurements of the gross beta activity of snow samples from four Alpine glaciers contaminated by radioactive fallout from the Chernobyl nuclear accident and a gamma-spectrum analysis of selected samples are reported. The results are discussed with respect to possible risks to the population from using meltwater from these glaciers as drinking water.

Accidents

Radiation sensitivity of Down's syndrome fibroblasts might be due to overexpressed Cu/Zn-superoxide dismutase (EC 1.15.1.1).

Trisomy 21 (Down's syndrome, DS) is the most frequent chromosomal aberration. Triplication of a small region of chromosome 21, the fragment 21q22 is sufficient to cause the DS phenotype including immunodeficiency, premature aging, neurodegenerations, mental retardation and an increased risk of leukemia. Chromosomal aberrations caused by X-ray irradiation were observed in DS lymphocytes and DS fibroblasts, but the correlation to cell death or repair deficiency was not clear. We approached this problem and report here on a profound X-ray repair deficiency of DS cells. With a colorimetric viability assay we observed an UV sensitivity of DS fibroblasts at doses beyond 14 Jm-2 but no significant X-ray sensitivity. By the nucleoid sedimentation technique, a deficient restoration of nucleoids in DS cells after X-ray irradiation was demonstrated. The same features apply for cells, which contain an overexpressed Cu/Zn-superoxide dismutase (SOD-1) gene. Radiation sensitivity of DS cells and SOD-1 overexpressing cells resemble those of ataxia telangiectasia (AT) fibroblasts. Additionally, DS and AT cells exert lack of inhibition of DNA synthesis after X-ray irradiation.

Cell Line

Displacement of Chernobyl fallout in snow layers of temperate Alpine glaciers.

Measurements of the gross-beta-activity and a gamma-spectrum analysis of radioactive fallout from Chernobyl distributed in vertical snow profiles on an Alpine glacier were carried out. Samples were collected in summer 1986 and in summer 1987. A displacement of isotopes to depths of approximately 6 m was observed. The mean activity per unit area amounts to 10.4 and 6.6 kBq m-2 for samples from 1986 and 1987, respectively, both values corrected to 1 May 1987. Isotopes with half-lives shorter than 110m Ag (250 days) could no longer be detected in 1987.

Accidents

Developmental modulation of a glial cell-associated glycoprotein, 5B12, in an insect, Acheta domesticus.

The expression of an insect (Acheta domesticus) adult glial cell-specific antigen, 5B12 undergoes major changes during development. The 5B12 antigen is detected as early as 20-25% of embryonic development, when immunoreactivity is distributed throughout the periphery, present at the luminal surface of epithelial cells which compose developing limb buds, sensory appendages, and the body cavity. The antigen is also localized on the cell surface of neural elements within commissural tracts in the embryonic CNS. 5B12 is secreted extracellularly in the periphery, where it is associated with the embryonic basal lamina in developing cercal sensory appendages. Luminal surface expression is transient, and disappears by 95% of embryonic development. As development proceeds, 5B12 distribution becomes more restricted, so that in the adult the antigen is predominantly associated with specific glial elements within the nervous system where it occurs as a specialized component of the extracellular matrix. The 5B12 antigen is also associated with discrete central and peripheral fiber tracts. Antigen 5B12 is present in whole embryos and in the adult CNS as a Mr 185-kDa glycoprotein. Distinct carbohydrate moieties with chondroitin sulfate-like properties are situated on the 5B12 epitope. Thus the glia-associated 5B12 macromolecule has the characteristics of a small proteoglycan. Based upon features of its distribution, pattern of spatiotemporal expression, and biochemical properties, it is speculated that 5B12 participates in events related sequentially to the development and the function of the insect nervous system.

Age Factors

Quantitative flow measurement with the fast Fourier flow technique.

The fast Fourier flow method of magnetic resonance (MR) imaging offers a fast and efficient way of measuring quantitative flow for velocities within the range from several millimeters per second to more than 1 m/sec. When fast Fourier flow imaging is used in combination with echocardiographic gating, arterial flow can be determined and velocity versus time profiles can be generated. Because of the high spatial resolution, down to 0.3 mm, detailed examination of flow profiles is possible even in smaller vessels. The method works equally well on a low-field-strength system operating at 0.23 T and on a high-field-strength system with 4.7-T field strength. Since the experiment is very fast, with acquisition times ranging from 4 seconds for a single-section experiment to about 4 minutes for the electrocardiographically gated variant, it can easily be combined with a conventional MR imaging examination.

Blood Flow Velocity

[Magnetic resonance in pediatric research and clinical practice. I. What can we expect from this new method?].

Nuclear Magnetic Resonance (NMR) was first observed over 40 years ago and has recently also entered the field of human medicine. It currently attracts increasing attention from biologists and clinicians alike, and the scope of its different applications is in a phase of explosive development. Two principle developments of the MR method are taking place over the recent years and are of special interest for pediatricians and neonatologists. One involves the possibility of obtaining images from any part of the human body, somewhat similar to those obtained with computer tomography (CT), but without any radiation hazard. Today clinicians are most familiar with this mode of MR application. The other development tries to adapt the MR method of elucidating the structure of molecules used in physics, molecular biology and organic chemistry for applications in medicine, allowing to study metabolism in vivo under non-invasive conditions. Again, such studies pose no health hazards and are, therefore, applicable to neonates and small infants. They will enhance our understanding of metabolic processes during normal development and disease, especially in organs like the brain, where biopsies are virtually impossible. Recent developments combine the two methods mentioned above, in order to obtain morphological as well as metabolic information from the same organ at the same time, which may provide even better insight into pathophysiological mechanisms and their response to therapeutic measures. This article attempts to give an overview to the medical researcher, the clinician, and especially the pediatrician and neonatologist of what MR is and what we can expect from it.

Brain

[One year after Chernobyl--radioactive cesium in breast milk].

Radioactivity in human breast milk was determined in 32 women in February and March 1987 by means of a Germanium detector. At this time radioactivity increased again by feeding the hay to the cattle harvested in the weeks following the disaster of Chernobyl. 8 (25%) of the values were above 0.3 nCi/l for babies milk recommended by the local authorities.

Accidents

[Obstetric aspects of radiation exposure following the Chernobyl accident].

Radioactivity was determined in the milk from 39 patients and in amniotic fluid, urine and placentas from 17 patients shortly after the Chernobyl disaster by means of a beta and gamma-scintillation counter. Elevated radioactivity (7.6 nCi/l beta activity and 7.4 nCi/l gamma activity) was found only in one sample of breast milk.

Accidents