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Biomedical subjects

E Lehmann

Publications and source records attributed to E Lehmann.

At least 19 recordsLinked to original sources
PubMed2006

Chemical and morphological changes of historical lead objects as a result of the use of electrolytic reduction as a stabilization treatment.

This paper focuses on the evaluation of the treatment related to chemical and morphological changes of corroded lead artifacts when using electrolytic reduction as a stabilization method. Synchrotron radiation X-ray diffraction and X-ray photoelectron spectroscopy were used to study the chemical changes of the corrosion layer and on the top nanometer of surface, respectively. Neutron tomography and scanning electron microscopy were used to visualize potential morphological changes on millimeter and micrometer level, respectively. The results of this study have shown that electrolytic reduction is a reliable way to stabilize and conserve active corroded lead artifacts. The corrosion products are actually converted into metallic lead, while the morphological changes due to the treatment are limited.

Journal Article↗
PubMed2006

Neutron phase imaging and tomography.

We report how a setup consisting of three gratings yields quantitative two- and three-dimensional images depicting the quantum-mechanical phase shifts of neutron de Broglie wave packets induced by the influence of macroscopic objects. Since our approach requires only a little spatial and chromatic coherence it provides a more than 2 orders of magnitude higher efficiency than existing techniques. This dramatically reduces the required measurement time for computed phase tomography and opens up the way for three-dimensional investigations of previously inaccessible quantum-mechanical phase interactions of neutrons with matter.

Journal Article↗
PubMed2006

Observation of the crossover from two-gap to single-gap superconductivity through specific heat measurements in neutron-irradiated MgB2.

We report specific heat measurements on neutron-irradiated MgB2 samples, for which the critical temperature is lowered to 8.7 K, but the superconducting transition remains extremely sharp, indicative of a defect structure extremely homogeneous. Our results evidence the presence of two superconducting gaps in the temperature range above 21 K, while single-gap superconductivity is well established as a bulk property, not associated with local disorder fluctuations, when Tc decreases to 11 K.

Journal Article↗
PubMed2005

[A rare case of birenal malacoplakia with renal failure].

HISTORY AND ADMISSION FINDINGS: A 45 year old man was admitted to our hospital because of fever, loss of appetite, and deterioration of general health. For two weeks the patient suffered from diarrhea which had resulted in moderate volume depletion. In addition, he complained of bilateral flank pain at the time of admission. Furthermore, the patient had a history of heavily drinking alcohol as well as cigarette smoking for many years. He had never attended a medical doctor before. INVESTIGATIONS: The patient presented with the clinical picture of acute renal failure and urosepticaemia which was caused by Escherichia coli. The kidneys were found to be at the upper limit of normal by sonography. Magnetic resonance imaging revealed signal-alterations in both kidneys with hyper- and hypointense zones in the renal parenchyma. DIAGNOSIS: To clarify the cause of rapid deterioration of renal function, we performed a renal biopsy. The histology of the renal specimen revealed an unusual type acute bacterial interstitial nephritis most likely due to an infection with E. coli. The clinical picture, the laboratory findings and renal histology, lead to the diagnosis of birenal malakoplakia. TREATMENT AND COURSE: After intravenous and subsequent oral antibiotic therapy the fever and the clinical signs of urosepticaemia subsided and renal function gradually improved. Antibiotic therapy and supplementation with vitamins were continued for 20 weeks. Five years after initial diagnosis, renal function was stable at a glomerular filtration rate of approximately 45 ml/min. CONCLUSIONS: Malakoplakia of the kidney is a rare form of bacterial interstitial nephritis and requires long-term antibiotic therapy.

Acute Kidney Injury↗
PubMed2005

[Abnormal responses to the loss of a loved one].

The loss of one's partner is always a stressful event. If this loss cannot be adequately coped with, depression, psychosomatic disorders or addictive disorders may result. In the worst case scenario, the victim of such a loss may resort to suicide or even kill the partner insisting on a separation. An active life, new personal contacts, or the support of a self-help group may help suffers to cope with the crisis more readily. Severe disorders--in part determined by the personality structure of the grieving partner--may require treatment by pharmaceuticals or cognitive therapy.

Adaptation, Psychological↗
PubMed2005

Neutron-induced electron radiography using an imaging plate.

Neutron-induced electron radiography is a technique suitable for inspection of thin samples. The first tests were performed with conventional X-ray films, which made it possible to distinguish between thicknesses of materials of the order of 1 microm. The objective of this work was to investigate the performance of the technique when an imaging plate is used instead of an X-ray film to register the image. Due to their wide dynamic range and much higher sensitivity, imaging plates offer significant advantages over the conventional X-ray films.

Journal Article↗
PubMed2004

Non-destructive 10B analysis in neutron transmission experiments.

Boron alloyed stainless-steel sheets are predominantly used in nuclear engineering as neutron shielding for radioactive waste disposal equipment. The neutron absorption depends strongly on the amount and the distribution of the 10B isotope. A systematic transmission study of 10B enriched steel plates by means of neutron time-of-flight and neutron radiography experiments was performed. The 10B content was analyzed with accuracy up to 5 x 10(-3) wt% using monochromatic beams and a linear increase of the macroscopic cross section with the 10B content was found even for strong absorbers. Then we extended the transmission analysis to "white" thermal neutron beams where large deviations from the exponential transmission law are observed. The influence of the spectral width is discussed in more detail because beam hardening causes an elevation of the effective transmission through strong absorbing materials, an effect which is crucial for the design of neutron shielding.

Journal Article↗
PubMed2004

The use of amorphous silicon flat panels as detector in neutron imaging.

A first test for neutron detection with a flat panel device based on the amorphous silicon technology is described in this report. The most important parameters defining the performance for neutron imaging are described. The first findings are encouraging for further improvements.

Journal Article↗
PubMed2003

[Does acupuncture influence the cardiac autonomic nervous system in patients with minor depression or anxiety disorders?].

We undertook this study to evaluate the effects of needle acupuncture on cardiac autonomic nervous system (ANS) function in patients with minor depression or anxiety disorder. Patients (n = 36) were randomly distributed into a verum acupuncture (VA) group (needles were applied at classical acupuncture points, e. g. He7, Pe6, Du20, Bl62, Ex6) or a placebo (PL) group (needles were applied only epidermal at non-acupuncture points). Both groups underwent standardized measurements of the 5-minute resting heart rate variability (HRV), which were performed before the first and after the 9th acupuncture session of an acupuncture series, and also three times (before the start and 5, respectively, 15 minutes after needle application) during the third acupuncture session. Demographic data between the VA and PL group did not differ. Before the start of acupuncture there were also no significant differences in HRV data between these groups. Compared to PL the VA group showed a significant decrease of the mean resting heart rate both, 5 and 15 minutes after needle application, combined with a trend towards an increase of the high frequency (HF; 0.15 - 0.4 Hz) and a decrease of the low frequency (LF; 0.04 - 0.15 Hz) spectral power. The latter effects resulted in an overall significant decrease of the mean LF/HF ratio in VA compared to PL treated patients. This pattern of findings suggests that in patients with minor depression or anxiety only verum acupuncture 1.) leads to a relative increase of cardiovagal modulation of heart rate and 2.) facilitates the physiological regulatory ANS function in response to alterations of external or internal environment. Clinical implications of these findings are discussed.

Acupuncture↗
PubMed2001

Modafinil for excessive daytime sleepiness in myotonic dystrophy.

The authors conducted an open-label trial of modafinil for excessive daytime sleepiness in myotonic dystrophy. Eleven patients were evaluated: two were not treated because of obstructive sleep apnea, and nine received 200 to 400 mg modafinil/day for an average of 16.4 weeks. There were no major side effects. Average sleep latency as measured by the Multiple Sleep Latency Test increased from 7.3 to 22.7 minutes ( p = 0.00013), and average Epworth Sleepiness Scale score decreased from 13.25 to 7.75 (p = 0.01028). Modafinil shows evidence of effectiveness for excessive daytime somnolence in myotonic dystrophy and should be investigated further.

Adult↗
PubMed2001

Control of GT repeat stability in Schizosaccharomyces pombe by mismatch repair factors.

The mismatch repair (MMR) system ensures genome integrity by removing mispaired and unpaired bases that originate during replication. A major source of mutational changes is strand slippage in repetitive DNA sequences without concomitant repair. We established a genetic assay that allows measuring the stability of GT repeats in the ade6 gene of Schizosaccharomyces pombe. In repair-proficient strains most of the repeat variations were insertions, with addition of two nucleotides being the most frequent event. GT repeats were highly destabilized in strains defective in msh2 or pms1. In these backgrounds, mainly 2-bp insertions and 2-bp deletions occurred. Surprisingly, essentially the same high mutation rate was found with mutants defective in msh6. In contrast, a defect in swi4 (a homologue of Msh3) caused only slight effects, and instability was not further increased in msh6 swi4 double mutants. Also inactivation of exo1, which encodes an exonuclease that has an MMR-dependent function in repair of base-base mismatches, caused only slightly increased repeat instability. We conclude that Msh2, Msh6, and Pms1 have an important role in preventing tract length variations in dinucleotide repeats. Exo1 and Swi4 have a minor function, which is at least partially independent of MMR.

Amino Acid Sequence↗
PubMed2001

Counteracting regulation of chromatin remodeling at a fission yeast cAMP response element-related recombination hotspot by stress-activated protein kinase, cAMP-dependent kinase and meiosis regulators.

In fission yeast, an ATF/CREB-family transcription factor Atf1-Pcr1 plays important roles in the activation of early meiotic processes via the stress-activated protein kinase (SAPK) and the cAMP-dependent protein kinase (PKA) pathways. In addition, Atf1-Pcr1 binds to a cAMP responsive element (CRE)-like sequence at the site of the ade6-M26 mutation, which results in local enhancement of meiotic recombination and chromatin remodeling. Here we studied the roles of meiosis-inducing signal transduction pathways in M26 chromatin remodeling. Chromatin analysis revealed that persistent activation of PKA in meiosis inhibited M26 chromatin remodeling, suggesting that the PKA pathway represses M26 chromatin remodeling. The SAPK pathway activated M26 chromatin remodeling, since mutants lacking a component of this pathway, the Wis1 or Spc1/Sty1 kinases, had no M26 chromatin remodeling. M26 chromatin remodeling also required the meiosis regulators Mei2 and Mei3 but not the subsequently acting regulators Sme2 and Mei4, suggesting that induction of M26 chromatin remodeling needs meiosis-inducing signals before premeiotic DNA replication. Similar meiotic chromatin remodeling occurred meiotically around natural M26 heptamer sequences. These results demonstrate the coordinated action of genetic and physiological factors required to remodel chromatin in preparation for high levels of meiotic recombination and eukaryotic cellular differentiation.

Cell Differentiation↗
PubMed2000

[Attitude of medical students to psychiatry. A study with the German translated, expanded version of the ATP-30].

Medical students' attitudes toward psychiatry are very important for the future care of psychiatric patients and the recruitment of qualified graduates. We examined the attitudes of 105 German medical students toward psychiatry using a German translation of the ATP-30, a reliable, self-administered questionnaire. In spite of a marked interest in psychiatry, most students thought it improbable that they would become psychiatrists. Attitudes toward psychiatry were generally positive (ATP-30 score: 104.6 +/- 13.4, where 90 represents middle, or neither positive nor negative) but showed clear differences in some aspects. Attitudes toward psychotherapy were markedly positive, while those toward psychiatric therapy in general or the scientific basis of psychiatry were less positive. We could find no influence of sex on the ATP score, whereas students having previous experience with psychiatry showed more positive attitudes towards it.

Adult↗
PubMed2000

[Treatment of perioperative anxiety in suspected breast carcinoma with a phytogenic tranquilizer].

OBJECTIVE: The present study examined the anxiolytic effect of the herbal preparation Kavosporal forte in 20 patients with situationally induced anxiety. MATERIAL AND METHODS: The degree of anxiety was acute in that the patients were waiting for the results of a histopathological diagnosis, carried out on account of suspect mammary findings, and therefore feared they were suffering from a mammary carcinoma. RESULTS: A significant reduction of anxiety compared with the placebo control was seen after a week's treatment with Kavosporal forte, levels of anxiety being measured a priori from the combined scores of two self-rating scales and one observer-rated scale. In addition, a significant increase was noted in alertness and a lessening of fatigue, introverted behavior and excitability as well as a reduction in levels of depression under the real therapeutic agent over the observation period. In none of the cases examined did any undesirable side effects occur, and the overall tolerance was also consistently good. CONCLUSIONS: It could therefore be concluded that the preparation under investigation is well suited of amelioration of the anxiety that arises regularly in connection with a mammary biopsy.

Adult↗
PubMed2000

[Acupuncture in patients with minor depressive episodes and generalized anxiety. Results of an experimental study].

In a placebo-controlled, randomized, modified double-blind study we investigated the effects of body needle acupuncture (n = 10) in 43 patients with minor depression (ICD 10 F32.0, F32.1) and 13 patients with generalized anxiety disorders (ICD10 F41.1). The severity of the disease was assessed by the Clinical Global Impression Scale (CGI). Treatment response was defined as a significant improvement in CGI. An intent-to-treat analysis was performed to compare treatment responses between verum- and placebo acupuncture. After completing an total of 10 acupuncture sessions the verum acupuncture group (n = 28) showed a significantly larger clinical improvement compared to the placebo group (Mann-Whitney test, p < 0.05). There were significantly more responders in the verum-compared to the placebo group (60.7% vs. 21.4%; chi-square test, p < 0.01). In contrast, no differences in the response rates were evident just after 5 acupuncture sessions. A multivariate analysis with the independent factor acupuncture (verum vs. placebo) and the results of the results of the additional rating scales (total score of HAMA, HAMD, Bf-S, BL) as dependent variables (ANOVA, 1:54 D.F.) revealed a clear trend towards lower HAMA scores in the verum group after completing 10 acupunctures (F3.29, p = 0.075). This corresponds well to the high response rate of 85.7% in patients with generalized anxiety disorders, in whom verum acupuncture was applied. Our results indicate that needle acupuncture (Du.20, Ex.6, He.7, Pe.6, Bl.62) leads to a significant clinical improvement as well as to a remarkable reduction in anxiety symptoms in patients with minor depression or with generalized anxiety disorders. The total sum of acupuncture sessions and the specific location of acupuncture needle insertions might be important factors for bringing about therapeutic success.

Acupuncture Therapy↗
PubMed2000

Blood oxidative stress and lipoprotein oxidizability in haemodialysis patients: effect of the use of a vitamin E-coated dialysis membrane.

BACKGROUND: Oxidative stress has been shown in haemodialysis patients in relation with an increased production of free radicals due to membrane-induced complement and leukocyte activation. In order to minimize membrane bioincompatibility and thereby oxidative stress, more compatible filters have been perfected. Among them, a high-flux vitamin E-coated membrane (CL-EE) has been proposed recently. In vivo, little data is available on the consequences of the use of vitamin E-coated membranes. In the present study, the effects of a 3-month use of CL-EE dialysis membranes compared to conventional membranes have been evaluated in 12 haemodialysis patients on the blood oxidative stress status before and after the dialysis session. METHODS: We determined the lipid peroxidation status (plasma thiobarbituric acid-reactive substances) and antioxidant defence (erythrocyte Cu,Zn-superoxide dismutase and plasma and erythrocyte glutathione peroxidase activities, plasma vitamin E, beta-carotene, vitamin A and total antioxidant status). Also, we simultaneously determined the antioxidant content and the copper oxidizability of isolated low density- and high density-lipoproteins (LDLs and HDLs). RESULTS: The main consequence observed under these conditions was a marked enrichment of plasma with vitamin E, which was also significantly and selectively noted in HDLs (no changes in LDL vitamin E content), perhaps related to a specific storage capacity for vitamin E in HDLs of haemodialysis patients. The beta-carotene content of plasma, LDLs and HDLs was also higher after use of vitamin E-coated membranes than after use of high-flux biocompatible membranes. HDL copper oxidizability was reduced (as shown by an increased lag time) before dialysis after use of CL-EE membranes compared to conventional membranes, whereas LDL oxidizability remained unchanged. CONCLUSION: A 3-month use of vitamin E-coated membranes resulted in a significant increase in plasma and HDL vitamin E content, associated with a lower oxidizability of HDLs, which could be beneficial for haemodialysis patients.

Adult↗
PubMed2000

[Autonomic nervous system and pancreas. (Analysis of the influence of different types of autonomic denervation in glandular regeneration phenomena and the interactions of the exocrine-endocrine-Axis)].

The present tests, in male Wistar rats, center around the trophic and functional changes of the pancreatic gland (R G), both exocrine and endocrine, induced by different types of autonomic nervous interruptions. First Group of Tests: Following one year celiac ganglionectomy (CG), nonpancreatectomized (Non-Pt) rats showed, basally, in blood, a drop of glucose (G), without changes of insulin (I). At autopsy, the CG animals showed an increase of the pancreatic we weight, of the total protein, of the RNA but not DNA. In the Pt. 95% rats, superimposing CG triggered, on the one hand, a drop to control values of the raised G blood levels, and on the other, a rise of I Besides, in feces, a rising of chymotrypsin concentration. At autopsy, in the PG, an increase of total protein and of RNA. Second Group of Tests: CG, after 6 months, induced, in blood, both basally and a 2 h glucose tolerance test, significant opposite enzyme activities changes in respect to C. Indeed, as amylase (A) was increased, that of lipase (L) was depressed. When alcohol feeding (AF) was superimposed to CG rats, a reversal of the L values was observed. The latter reached levels significantly higher those of the C. In in-vitro tests, the isolated islets of CG disclosed to release more I to the bath medium than those of the C animals. Third Group of Tests: Analyzing, in conscious animal, the L excretory changes in the basal bile pancreatic secretion (BB-PS) induced by chronic (2 months interruption of the autonomic nervous innervation of the PG, it was found that CG, truncal vagotomy (V), the association of CG + V, peri-Vaterian duodenotomy (PV-D), but not bilateral splachicectomy (Spl), inhibit, significantly the L output. It was also shown that superimosing AF to the V or CG + V animals reverted to C values the I depressed levels. In acute interruptions (24 h) of the autonomic nervous innervation of the PG: CG, V, P. V-D, the depression in the BBPS is highly significant, more than 40%. From these three sets of experiments it is concluded that: Firstly, CG increases the regenerative and functional capacity of both the exocrine pancreas. This is distinctively evident when the secretory mass is reduced like in the Pt. 95% series of animals. CG probably exerts its effects suppressing the releasing of some negative reins: adrenergic, pepdidergic (galanin). Secondly, CG evokes modifications of the normal Islet-pancreon inter-relationships. The rising of A and the drop of L in blood elicited by this type of autonomic nervous interruption probably reflects an increased release of I by the Langerhans islet. Thirdly, CG, the same as V. CG + V and P.V-D, but not Spl, depress the intrapancreatic cholinergic tone. This might by at the basis of the depression of L excretion in the BB-PS. The reversion to C Through the coupling of chronic alcohol intoxication to the autonomic decentralized PG would be a reflection of an increased sensitivity to ethanol of the intrapancreatic ganglionic neurons. The augmented acetylcholine release at the nerve terminal would lead to a high intrapancreatic cholinergic tone that, in the end, might be at the basis of the reversal changes induced in the autonomic decentralized PG by the chronic ethanol intoxication.

Animals↗