Showing papers by "Free University of Berlin published in 1989"
TL;DR: The study of the energy of infinitesimal deformations is finally extended to include the third variation and the critical value of spontaneous curvature is obtained, below which oblate ellipsoids of a deformed sphere are more stable than prolate ones.
Abstract: A general equation of mechanical equilibrium of fluid membranes subject to bending elasticity [reported in Phys. Rev. Lett. 59, 2486 (1987)] is derived in detail. The second variation of the shape energy, also obtained for arbitrary shapes, is used to analyze stability with respect to deformational modes for spherical and cylindrical vesicles. The former analysis is well known, while the latter is presented here for the first time. The theoretical results are shown to agree very well with previous numerical calculations. In addition, they provide the energies controlling the shape fluctuations and show that spontaneous curvature may transform cylinders into tapes or strings of beads. The study of the energy of infinitesimal deformations is finally extended to include the third variation. Applying the general result to the sphere, we obtain the critical value of spontaneous curvature below which oblate ellipsoids of a deformed sphere are more stable than prolate ones. It is shown to be the same regardless of whether volume or pressure is kept constant.
615 citations
TL;DR: In this paper, the theory of superselection sectors is generalized to situations in which normal statistics has to be replaced by braid group statistics, and the essential role of the positive Markov trace of algebraic quantum field theory for this analysis is explained.
Abstract: The theory of superselection sectors is generalized to situations in which normal statistics has to be replaced by braid group statistics. The essential role of the positive Markov trace of algebraic quantum field theory for this analysis is explained, and the relation to exchange algebras is established.
495 citations
TL;DR: In situ hybridization revealed that in two HD cases, the EBV infected cells had the distinct morphology of Hodgkin and Reed-Sternberg cells, thus suggesting a direct pathoetiological relationship between EBV and some cases of HD.
394 citations
TL;DR: Patients with high or lower left ventricular ejection fraction, higher or lower degree of wall motion abnormalities and residual stenosis of the coronary arteries, and one-, two-, or three-vessel disease exhibited a similar circadian pattern, suggesting that the morning is a risk period for patients with mild as well as severe coronary artery disease.
Abstract: The time of acute myocardial infarction was determined in all 1,741 patients of the ISAM (Intravenous Streptokinase in Acute Myocardial Infarction) Study, based on onset of clinical symptoms and evaluation of plasma CK-MB enzyme time-activity curves. The incidence of myocardial infarction was markedly increased between 6:00 AM and 12:00 noon compared with other times of day (p less than 0.001). Myocardial infarction occurred 3.8 times more frequently between 8:00 and 9:00 AM (hour of maximum incidence) than between 12:00 midnight and 1:00 AM (hour of minimum incidence). Time of myocardial infarction based on clinical and enzymatic methods correlated well (r = 0.95). Patients with higher or lower left ventricular ejection fraction, higher or lower degree of wall motion abnormalities and residual stenosis of the coronary arteries, and one-, two-, or three-vessel disease exhibited a similar circadian pattern, suggesting that the morning is a risk period for patients with mild as well as severe coronary artery disease. Only the group of patients receiving beta-adrenergic blocking therapy before the event did not show an increased morning incidence of myocardial infarction. This observation may contribute to an understanding of the mechanisms by which beta-blockers reduce the incidence of myocardial infarction. Further investigation of physiologic changes occurring during the morning period of increased risk of myocardial infarction may lead to better understanding of the disorder. Design and timing of cardioprotective medication may play a crucial role in improving prevention of acute myocardial infarction.
365 citations
TL;DR: The HIV-infected patients with gastrointestinal symptoms show low-grade small bowel atrophy and a maturational defect in enterocytes, which may be caused exclusively by HIV.
Abstract: Excerpt Study Objective:To determine small intestinal mucosal structure and function in patients with human immunodeficiency virus (HIV) infection. Design:Prospective, consecutive sample study. Set...
361 citations
TL;DR: The distribution of red cell and blood volume flow was studied at 65 arteriolar bifurcations in the rat mesentery to study the dependence of fractional red cell volume flow on fractional blood flow and the shape of the radial hematocrit profile in the feeding vessel has been calculated.
337 citations
TL;DR: The diagnostic value of the Ber-H2 MoAb was most significant for a group of anaplastic large-cell lymphomas (ALC) lymphomas, of which more than 50 cases could be investigated, owing to applicability in paraffin sections.
324 citations
TL;DR: The expression of alpha 2(I), alpha 1(III) and alpha 1 (IV) procollagen mRNA was analyzed in normal and CCl4-induced fibrotic rat liver by in situ hybridization using RNA probes as mentioned in this paper.
279 citations
TL;DR: The results indicate that endothelial cells contain a cytosolic enzyme which is directly or indirectly regulated by Ca2+ and converts L-arginine into a compound which in stimulating soluble guanylyl cyclase behaves similar to endothelium-derived relaxing factor.
274 citations
TL;DR: Both the proton and azide effects, which are absent in wild type, indicate that the internal donor is removed and that the reprotonation pathway is different from wild type in these mutants.
Abstract: Above pH 8 the decay of the photocycle intermediate M of bacteriorhodopsin splits into two components: the usual millisecond pH-independent component and an additional slower component with a rate constant proportional to the molar concentration of H+, [H+]. In parallel, the charge translocation signal associated with the reprotonation of the Schiff base develops a similar slow component. These observations are explained by a two-step reprotonation mechanism. An internal donor first reprotonates the Schiff base in the decay of M to N and is then reprotonated from the cytoplasm in the N----O transition. The decay rate of N is proportional to [H+]. By postulating a back reaction from N to M, the M decay splits up into two components, with the slower one having the same pH dependence as the decay of N. Photocycle, photovoltage, and pH-indicator experiments with mutants in which aspartic acid-96 is replaced by asparagine or alanine, which we call D96N and D96A, suggest that Asp-96 is the internal proton donor involved in the re-uptake pathway. In both mutants the stoichiometry of proton pumping is the same as in wild type. However, the M decay is monophasic, with the logarithm of the decay time [log (tau)] linearly dependent on pH, suggesting that the internal donor is absent and that the Schiff base is directly reprotonated from the cytoplasm. Like H+, azide increases the M decay rate in D96N. The rate constant is proportional to the azide concentration and can become greater than 100 times greater than in wild type. Thus, azide functions as a mobile proton donor directly reprotonating the Schiff base in a bimolecular reaction. Both the proton and azide effects, which are absent in wild type, indicate that the internal donor is removed and that the reprotonation pathway is different from wild type in these mutants.
272 citations
TL;DR: In the last decade, a great deal of research has been devoted to the question whether social support has a favorable impact on the maintenance of physical health and on coping with illness.
Abstract: In the last decade a great deal of research has been devoted to the question whether social support has a favorable impact on the maintenance of physical health and on coping with illness. It is cl...
TL;DR: Although absolute values of ScvO2 are not sufficiently identical to SvO2 to calculate O2 uptake or pulmonary shunt precisely, close tracking of changes in the two sites across a wide range of hemodynamic conditions warrant further consideration of ScVO2 for patient monitoring of trends in O2 supply/demand.
TL;DR: It is concluded that ACTH deficiency may cause the syndrome of inappropriate secretion of antidiuretic hormone, and the beneficial effect of hydrocortisone is probably exerted through the suppression of vasopressin secretion.
Abstract: Severe hyponatremia occurs in some patients with untreated hypopituitarism, but it is not known whether such hyponatremia is caused by the hypersecretion of vasopressin (antidiuretic hormone). This report describes severe, symptomatic hyponatremia in five women 59 to 83 years old (serum sodium, 111 to 118 mmol per liter) who presented with hypopituitarism (which had been previously undiagnosed in four). Plasma vasopressin was inappropriately high (1.3 to 25.8 pmol per liter [1.4 to 28 ng per liter]) in relation to plasma osmolality (236 to 260 mOsm per kilogram of body weight). All five patients had normal renal function and no signs of dehydration or volume depletion. The hyponatremia was resolved within a few days after the institution of hydrocortisone therapy, after infusion of normotonic or hypertonic saline had been found to be less effective. When four of the patients were later restudied while receiving maintenance hydrocortisone treatment, the relation between plasma vasopressin and osmo...
TL;DR: The data suggest that at least one NDRF is identical with NO or another labile NO containing compound derived from arginine, and the formation and release of NO was enhanced several‐fold in the presence of superoxide dismutase.
TL;DR: A neutron diffraction study of spectroscopic states for the light-energized proton pump bacteriorhodopsin (BR) finds reversible structural changes of the protein were detected in the BR-568 to M-state transition.
Abstract: A neutron diffraction study of spectroscopic states for the light-energized proton pump bacteriorhodopsin (BR) is presented The photocycle states BR-568 and M were generated at temperatures above 4 degrees C and were measured after trapping at--180 degrees C In the BR-568 to M-state transition, which is known to be a key step in transmembrane proton pumping, reversible structural changes of the protein were detected These structural alterations occur in the neighborhood of the cyclohexene ring and at the Schiff's base end of the chromophore retinal They are interpreted as a 1-2 degree tilt of three or four of the transmembrane alpha-helices or as positional changes of four or five amino acids The structural changes observed are inherent in the transport mechanism of bacteriorhodopsin
TL;DR: In this article, the size and structural dependence of magnetic properties of small clusters were determined by using a tight-binding Hubbard Hamiltonian in the unrestricted Hartree-Fock approximation.
Abstract: The size and structural dependence of magnetic properties of small ${\mathrm{Cr}}_{\mathrm{n}}$, ${\mathrm{Fe}}_{\mathrm{n}}$, and ${\mathrm{Ni}}_{\mathrm{n}}$ clusters are determined by using a tight-binding Hubbard Hamiltonian in the unrestricted Hartree-Fock approximation. Results are given for the average magnetic moment \ensuremath{\mu}${\ifmmode\bar\else\textasciimacron\fi{}}_{n}$, local magnetic moments, and magnetic ordering at T=0. We obtain for ${\mathrm{Fe}}_{\mathrm{n}}$ (n\ensuremath{\le}15) that \ensuremath{\mu}${\ifmmode\bar\else\textasciimacron\fi{}}_{n}$ varies as a function of n due to the interplay between the changes in coordination number and bond length as a function of cluster size, which may be related to recent experiments. The dependence of the structural cluster stability on magnetism is discussed. Results are also given for the cohesive energy, average bond length, and local densities of states.
TL;DR: It is postulate that the tumor cells in many cases of Hodgkin's disease and some cases of Ki-1-ALC may be derived from immature lymphoid cells by a transformation process that superimposes characteristics of mature activated lymphocytes on these cells.
01 Dec 1989
TL;DR: It is proved that any set ofn points inEd admits a spanning tree which cannot be cut by any hyperplane (or hypersphere) through more than roughlyn1−1/d edges, and this result yields quasi-optimal solutions to simplex range searching in the arithmetic model of computation.
Abstract: The range-searching problems that allow efficient partition trees are characterized as those defined by range spaces of finite Vapnik-Chervonenkis dimension. More generally, these problems are shown to be the only ones that admit linear-size solutions with sublinear query time in the arithmetic model. The proof rests on a characterization of spanning trees with a low stabbing number. We use probabilistic arguments to treat the general case, but we are able to use geometric techniques to handle the most common range-searching problems, such as simplex and spherical range search. We prove that any set ofn points inEd admits a spanning tree which cannot be cut by any hyperplane (or hypersphere) through more than roughlyn1Â?1/d edges. This result yields quasi-optimal solutions to simplex range searching in the arithmetic model of computation. We also look at polygon, disk, and tetrahedron range searching on a random access machine. Givenn points inE2, we derive a data structure of sizeO(n logn) for counting how many points fall inside a query convexk-gon (for arbitrary values ofk). The query time isO(Â?kn logn). Ifk is fixed once and for all (as in triangular range searching), then the storage requirement drops toO(n). We also describe anO(n logn)-size data structure for counting how many points fall inside a query circle inO(Â?n log2n) query time. Finally, we present anO(n logn)-size data structure for counting how many points fall inside a query tetrahedron in 3-space inO(n2/3 log2n) query time. All the algorithms are optimal within polylogarithmic factors. In all cases, the preprocessing can be done in polynomial time. Furthermore, the algorithms can also handle reporting within the same complexity (adding the size of the output as a linear term to the query time).
TL;DR: The integrity of the basement membrane is likely to play a role in determining the route of entry and limit of spread of Y. enterocolitica infection.
Abstract: The experimental infection of mice with Yersinia enterocolitica serotype O8 was investigated in a quantitative and histological study. The course of bacterial penetration and spreading was precisely determined by immunohistochemical staining. After oral administration, the bacteria passed the epithelial barrier of the ileum and spread into the lamina propria. By preference they entered Peyer's patches, which were about 1,000 times more heavily colonized than the surrounding epithelium of a comparable surface area. The bacteria proliferated in the follicles, from which they spread into the lamina propria of the villi. At either site most of the bacteria multiplied extracellularly, with only a small percentage observed to be present within the phagocytes. The bacteria did not appear to be able to pass the intact basement membrane; hence, the integrity of the basement membrane is likely to play a role in determining the route of entry and limit of spread of Y. enterocolitica infection.
TL;DR: Data confirm previous findings of the group in patients after kidney transplantation, indicating that prophylactic and/or therapeutic application of calcium channel blockers is of substantial value in preventing ischaemic or toxic renal injury.
Abstract: Despite the development of new non-ionic low-osmolality contrast media, nephrotoxicity of intravascular radio-opaque contrast media remains a severe clinical problem, particularly in patients with risk factors. Widely accepted mechanisms of contrast-media-induced nephrotoxicity are disturbances of renal microcirculation due to prolonged intrarenal vasoconstriction, and direct damaging effects on glomerular and tubular cells. Calcium channel blocking agents have been shown experimentally and clinically to ameliorate ischaemic and toxic renal injury. In the present prospectively randomised, double-blind clinical trial, we investigated a total of 35 patients after intravascular administration of contrast media to determine the effects on renal function of a 3-day treatment with the calcium channel blocker nitrendipine (20 mg/day orally, starting 1 day before X-ray examination, n = 16), compared to findings in a placebo-treated control group (n = 19). Despite the fact that baseline renal function was significantly more compromised in the investigational group, the prophylactic application of nitrendipine preserved the glomerular filtration rate, whereas control patients showed a significant (27%) reduction in GFR on day 2 after contrast-media injection (P less than or equal to 0.01). Moreover, the increase in enzymuria of three different renal enzymes (gamma-GT, AAP, and beta-NAG), as well as urinary protein excretion, was significantly ameliorated by nitrendipine. These data confirm previous findings of our group in patients after kidney transplantation, indicating that prophylactic and/or therapeutic application of calcium channel blockers is of substantial value in preventing ischaemic or toxic renal injury.(ABSTRACT TRUNCATED AT 250 WORDS)
TL;DR: The evidence that pyrimidine nucleotides exert their effects by binding to distinct pyrimidinoceptors, which are coupled to pertussis toxin-sensitive G proteins in human phagocytes is reviewed.
01 Jan 1989
TL;DR: The LISREL program has since been gradually improved (LISREL III: Joreskog & van Thillo 1973; LIS RELA as discussed by the authors, LISLLAR VI: Jorekog and van Driel 1978, JoresKog 1981, Fornell & Bookstein 1982, Rindskopf 1983, 1984).
Abstract: The Latent Variables Path (LVP) model and also the first viable estimation technique were developed by Karl Joreskog (from 1973 onwards). Right from the beginning his LISREL method was of the utmost elegance and perfection, as regards the deductive properties of the model. The LISREL program has since been gradually improved (LISREL III: Joreskog & van Thillo 1973; LISREL VII: Joreskog & Sorbom 1987), as regards convenience for the user, additional estimation criteria and model diagnostics. However, one inconvenient side of LISREL, well known to all users, is incurable: LISREL tends to produce improper solutions characterized by negative variance estimates and LV correlations greater than unity (van Driel 1978, Joreskog 1981, Fornell & Bookstein 1982, Rindskopf 1983, 1984).
TL;DR: It is assumed that the “face-specific” components in electroencephalographic responses evoked by changes in pictorial patterns do not originate in the temporo-occipital cortical face region, but in limbic structures deep in the temporal lobe or in the gyrus cinguli.
Abstract: In three different experimental series, electroencephalographic responses evoked by changes in pictorial patterns were recorded in 29 adult human subjects (19 females, 10 males). Quantitative data evaluation for the evoked responses from electrodes T5, T6, Cz, Pz (10–20 system) was performed. The stimuli were projected to a 4 × 6 degree binocularly viewed field. The patterns changed within 6 ms every 2.5–4.5 s according to a random program. Paradigm (1): Identical line drawings of a face, a tree and a chair were used, either black on white (P-stimuli) or white on black (N-stimuli); in each set altogether 160 slides appeared in semi-random order. At Cz and Pz a prototypical EEG-response evoked by face stimuli was found exhibiting 3 prominent peaks, very similar for P-stimuli and N-stimuli. A P150 maximum was especially pronounced in the responses to face stimuli but absent in the evoked potentials aroused by chair or tree stimuli. The difference curves (face-chair, face-tree, chair-tree) supported the hypothesis of “face-responsive” components in these responses. Paradigm (2): 4×6 degree slides (black and white photographs) of 54 different human faces, 53 different vases and 53 different pairs of shoes were projected as in paradigm (1), but instruction to the subjects on a supposed post-test memory task raised their attention during the recordings. “Face-responsive” components (an early N 140–160, P 210–240, N 300) were more marked in female than in male subjects, and again most pronounced at electrode Cz. Paradigm (3): When a recognition task was included in paradigm (2) — 9 out of 192 items were memorized 20 minutes before the recording session — essentially the same evoked potentials were obtained as in (2), but an additional late positive wave (450–600 ms) appeared in the responses to all stimuli. We assume that the “face-specific” components — a designation which is used cautiously considering the limited number of non-face stimuli — do not originate in the temporo-occipital cortical face region, but in limbic structures (amygdala, hippocampus) deep in the temporal lobe or in the gyrus cinguli. In the present study no significant hemispheric differences (T5, T6) in the evoked responses were found (all stimulus categories), but such differences are known to appear with highly schematic face stimuli.
TL;DR: The results indicate that bovine brain contains a cytosolic enzyme which uses NADPH or NADP+ as cofactors to form nitrogen oxides from both an endogenous non-dialyzable substrate and from L-arginine.
TL;DR: The results suggest that Asp-96 serves as an internal proton donor in the proton-uptake pathway from the cytoplasm to the Schiff base, providing a kinetic explanation for the fact that at pH 7 and saturating light intensities the steady-state proton pumping is almost abolished in the AsP-96----Asn mutant.
Abstract: The photocycle, electrical charge translocation, and release and uptake of protons from the aqueous phase and release and uptake of protons from the aqueous phase were investigated for bacteriorhodopsin mutants with aspartic acid-96 replaced by asparagine or glutamic acid. At neutral pH the main effect of the Asp-96----Asn mutation is to slow by 2 orders of magnitude the decay of the M intermediate and the concomitant charge displacement associated with the reprotonation of the Schiff base from the cytoplasmic side of the membrane. The proton uptake measured with the indicator dye pyranine is likewise slowed without affecting the stoichiometry of proton pumping. The corresponding results for the Asp-96----Glu mutant, on the other hand, are very close to those for the wild-type protein. These results provide a kinetic explanation for the fact that at pH 7 and saturating light intensities the steady-state proton pumping is almost abolished in the Asp-96----Asn mutant but is close to normal in the Asp-96----Glu mutant. Thus, the pump is simply turning over much more slowly in the Asp-96----Asn mutant. The time constants of the decay of M and the associated charge translocation increase strongly with increasing pH for the Asp-96----Asn mutant but are virtually pH-independent for the Asp-96----Glu mutant and wild-type bacteriorhodopsin. At pH 5 the M decay of the Asp-96----Asn mutant is as fast as for wild type. These results suggest that Asp-96 serves as an internal proton donor in the proton-uptake pathway from the cytoplasm to the Schiff base.
01 Jan 1989
TL;DR: Criteria-based content analysis (CBCA) and statement validity assessment (SVA) are semi-standardized methods for the credibility assessment of children's statements in cases of sexual abuse as mentioned in this paper.
Abstract: Criteria-based content analysis (CBCA) and statement validity assessment (SVA) are semi-standardized methods for the credibility assessment of children’s statements in cases of sexual abuse. CBCA consists of a systematic analysis of the content of children’s statements using a set of defined criteria, while SVA incorporates additional information from other sources than the statement itself. This chapter provides condensed descriptions of CBCA and SVA and summarizes recent simulation and field studies on the validity of CBCA. The results of these studies demonstrate the usefulness of CBCA for the purpose of credibility assessment of children’s statements about sexual abuse.
TL;DR: This finding demonstrates that the release of the Ki‐1 antigen takes place not only in vitro, but in vivo as well, and implies that the Ki-1 antigen may be used as a serum tumor marker.
Abstract: An enzyme-linked immunosorbent assay (ELISA) has been developed that allows the quantitative determination of the Ki-1 (CD30) antigen in soluble form. Similar levels of sensitivity of this new Ki-1 ELISA and the ELISA previously described for measuring the soluble 55-kDa chain of the interleukin 2 receptor were seen. As assessed with this ELISA, the investigated Ki-1+ permanent cell lines released the Ki-1 antigen into the culture supernatant. In culture supernatants of concanavalin A-activated human peripheral blood lymphocytes, however, this antigen could not be detected. The released Ki-1 antigen has an apparent molecular weight (Mr) of 85,000, whereas the cell-associated Ki-1 antigen has an Mr of 105,000. We investigated sera from 30 normal donors, 15 patients with systemic infections, and 63 patients suffering from lymphomas for soluble Ki-1 antigen. In all sera from normal donors and patients with systemic infectious diseases, soluble Ki-1 antigen was below the detection limit (i.e., less than 70 pg). In contrast, high amounts of the soluble Ki-1 antigen were found in sera from 18 malignant lymphomas containing Ki-1+ tumor cells. This finding demonstrates that the release of the Ki-1 antigen takes place not only in vitro, but in vivo as well. Moreover, these results imply that the Ki-1 antigen may be used as a serum tumor marker.
TL;DR: The sensitivity and specificity values of various parameters tested for their ability to predict the clinical course of a patient with Graves' disease were too low to be useful for daily clinical decisions in the treatment of an individual patient.
Abstract: Graves' disease is an autoimmune disease characterized by a course of remission and relapse. Since the introduction of antithyroid drug treatment, various parameters have been tested for their ability to predict the clinical course of a patient with Graves' disease after drug withdrawal. Nearly all these studies were retrospective [corrected] and often yielded conflicting results. In a prospective multicentre study with a total of 451 patients, we investigated the significance of a variety of routine laboratory and clinical parameters for predicting a patient's clinical course. Patients who had positive TSH receptor antibodies activity at the end of therapy showed a significantly higher relapse rate than those without (P less than 0.001). However, the individual clinical course cannot be predicted exactly (sensitivity 0.49, specificity 0.73, N = 391). The measurement of microsomal (P = 0.99, sensitivity 0.37, specificity 0.63, N = 275) or thyroglobulin antibodies (P = 0.76, sensitivity 0.18, specificity 0.84, N = 304) at the end of antithyroid drug therapy did not show a statistically significant difference in the antibody titre between the patients of the relapse and those of the remission group. Additionally, HLA-DR typing (HLA-DR3: P = 0.37, sensitivity 0.36, specificity 0.58, N = 253) was proven to be unsuitable for predicting a patient's clinical course. Patients with abnormal suppression or an abnormal TRH test at the end of antithyroid drug therapy relapse significantly more often (P less than 0.001) than patients with normal suppression or normal TRH test. Patients with a large goitre also have a significantly (P less than 0.001) higher relapse rate than those with only a small enlargement. The sensitivity and specificity values of all these parameters, however, were too low to be useful for daily clinical decisions in the treatment of an individual patient. This is also true for the combinations of different parameters. Though the highest sensitivity value (0.94) was found for a combination of the suppression and the TRH test at the end of therapy, the very low specificity value (0.13) for this combination reduced its clinical usefulness.
TL;DR: Cultivation of human peripheral lymphocytes in the presence of 50-Hz electromagnetic fields does not alter the spontaneous frequencies of sister-chromatid exchanges (SCE) and of chromosomal aberrations (CA), but leads to an enhancement of the cell cycle progression of HPLs in vitro.
Abstract: Cultivation of human peripheral lymphocytes (HPL) in the presence of 50Hz electromagnetic fields (EMFs) does not alter the spontaneous frequencies of sister-chromatid exchanges (SCE) and of chromosomal aberrations (CA), but leads to an enhancement of the cell cycle progression of HPLs in vitro. Pretreatment of HPLs with trenimon (TRN), diepoxybutane (DEB), or methylnitrosournea (MNU) in the G 0 phase of the cell cycle results in dose-dependent elevations of the SCE frequencies. In some cases culturing of HPLs pretreated with MNU or TRN in the presence of EMFs led to significantly higher frequencies of SCEs when compared to cells cultivated in the absence of EMDs. Since we did not use multiple fixation times these data may rather result from differential influences on HPL subsets than from EMF exposure.