Therapy-related acute myelogenous leukaemia (t-AML) in a patient with multiple sclerosis treated with mitoxantrone.
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Adult↗
Biomedical subjects
E Koch
Publications and source records attributed to E Koch.
Homogeneous sphere packings with triclinic symmetry.
All homogeneous sphere packings with triclinic symmetry have been derived by studying the characteristic Wyckoff positions P -1 1a and P -1 2i of the two triclinic lattice complexes. These sphere packings belong to 30 different types. Only one type exists that has exclusively triclinic sphere packings and no higher-symmetry ones. The inherent symmetry of part of the sphere packings is triclinic for 18 types. Sphere packings of all but six of the 30 types may be realized as stackings of parallel planar nets.
Journal Article↗
Group-theoretical and geometrical considerations of the phase transition between the high-temperature polymorphs of quartz and tridymite.
A model was derived for the temperature-dependent phase transition between the high-temperature polymorphs of quartz (P6(4)22) and tridymite (P6(3)/mmc). Only the Si framework is considered, and the transformation can be described as a deformation of a homogeneous sphere packing with three contacts per sphere (type 3/10/h1) in the common subgroup P6(1)22 of P6(4)22 and P6(3)/mmc. The proposed model guarantees the three-dimensional connection of the crystal structure during the whole transformation process.
Journal Article↗
Pigmented corpuscles in the midgut gland of Pomacea canaliculata and other Neotropical apple-snails (Prosobranchia, Ampullariidae): a possible symbiotic association.
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Animals↗
Inhibition of inflammatory cytokine production and lymphocyte proliferation by structurally different sesquiterpene lactones correlates with their effect on activation of NF-kappaB.
Many sesquiterpene lactones (Sls) are known to possess anti-inflammatory activities. To gain further insight into their structure-activity relationships and the molecular mechanism of action, four germacranolide sesquiterpene lactones which differ in the skeleton and the number of reactive centers (4beta,15-epoxy-miller-9E-enolide (1), 15-acetoxy-eremantholide B (2), a mixture of 15-(isovaleroyl)/15-(2-methyl-butyryl)-2alpha-acetoxy-miguanin (3), and 15-(2-hydroxy)-isobutyryloxy-micrantholide (4)) were investigated for their effect on production of proinflammatory cytokines (interleukin-1beta [IL-1beta], IL-6, and tumor necrosis factor-alpha [TNF-alpha]) as well as proliferation of concanavalin A (Con A) and lipopolysaccharide (LPS)-stimulated mouse lymphocytes. Compounds 1 and 3 which possess an alpha-methylene-gamma-lactone function and a conjugated carbonyl group induced a half-maximal inhibition of cytokine synthesis in adherent mouse peritoneal exudate cells at micromolar concentrations (IC(50) 0.69-1.70 microM), while compound 4 which contains only an alpha-methylene-gamma-lactone residue was less active (IC(50) > or 38 microM). Interestingly, compound 2, which carries only a conjugated keto group, displayed a potency similar to those of the bifunctional compounds 1 and 3. All four Sls suppressed proliferation of murine lymphocyte at IC(50) concentrations between 0.22 and 5.03 microM. The rank order of potency was 1 = 2 > 3 > 4. Generally, the growth of LPS-stimulated cells was more strongly influenced than those of Con A-activated lymphocytes. This effect was particularly pronounced with 4. Inhibitory concentrations correlated well with those necessary for inhibition of the transcription factor nuclear factor kappaB (NF-kappaB) observed in a previous investigation. Therefore, it can be assumed that NF-kappaB may be involved in the suppressive effect of Sls on cytokine production and lymphocyte proliferation.
Animals↗
A proposal for a transition mechanism from the diamond to the lonsdaleite type.
A phase transition between the diamond (Fd3;m) and the lonsdaleite types (P6(3)/mmc) may be described as a deformation of a homogeneous sphere packing with three contacts per sphere (type 3/10/o1) in the common subgroup Pnna of Fd3;m and P6(3)/mmc. The frequently observed transition between the zinc-blende (F4;3m) and the wurtzite types (P6(3)mc) may be described in an analogous way as a deformation of a heterogeneous sphere packing in the subgroup Pna2(1). The proposed model guarantees the three-dimensional connection during the whole transformation process. By this property it is distinguished from other models.
Journal Article↗
Hyperforin stimulates intracellular calcium mobilisation and enhances extracellular acidification in DDT1-MF2 smooth muscle cells.
Hyperforin, an acylphloroglucinol derivative, is a major constituent of St. John's wort extract (Hypericum perforatum L.), which is used in treating depressive disorders. Hyperforin has been demonstrated as a modulator of several neuronal ion channels, and inhibits smooth-muscle contraction induced by various neurotransmitters. To evaluate the spasmolytic properties of hyperforin in more detail, we performed studies on the hamster vas deferens smooth muscle cell line DDT1-MF2. In a first series of experiments, we determined the effect of hyperforin on intracellular Ca2+ concentration ([Ca2+]i) using the fluorochrome fura-2. These investigations were supplemented in a second series of assays, where the effects on cellular metabolism were analysed by measuring the rate of extracellular release of acidic metabolites with the help of a microphysiometer. Hyperforin (0.3-10 microg/ml) caused a concentration-dependent elevation of [Ca2+]i and extracellular acidification rate (ECAR). Both of these effects were independent of extracellular Ca2+. To elucidate whether the increase of [Ca2+]i by hyperforin causes or results from its ECAR-stimulating properties, we used various pharmacological tools to reveal the sequence of events and the molecular mechanisms involved. Our results suggest that hyperforin induces release of Ca2+ from as yet unidentified sources. Since the ECAR stimulation was inhibited to a different extent by the intracellular Ca2+ chelator BAPTA as well as by inhibitors of plasmalemmal and mitochondrial Na+/Ca2+ exchange, but not by inhibitors of Na+/H+ antiport, the intracellular Ca2+ increase seems to be essential for this hyperforin effect. However, further studies are needed to establish the exact mode of action, and to deduce whether this aspect of hyperforin activity contributes to its antidepressant and neuroprotective effects.
Acids↗
Extracts from fruits of saw palmetto (Sabal serrulata) and roots of stinging nettle (Urtica dioica): viable alternatives in the medical treatment of benign prostatic hyperplasia and associated lower urinary tracts symptoms.
Benign prostatic hyperplasia (BPH) and associated lower urinary tract symptoms (LUTS) are very common disorders in aging men. Despite the great clinical importance, many aspects of their aetiology remain uncertain although it is generally accepted that advanced age and testicular androgens are important requirements for the development of these complaints. The currently available therapeutic options include watchful waiting, changes of life style, medical treatments and invasive therapies. In many European countries the use of phytopharmaceuticals for the management of BPH and related LUTS is common and these products represent up to 80 % of all drugs prescribed for this disorder. In particularly, extracts from the fruits of saw palmetto (Sabal serrulata, syn. Serenoa repens) and the roots of stinging nettle (Urtica dioica) are popular. During the last years numerous papers have been published which elaborated on the pharmacological activities and the clinical assessment of these herbal remedies. These investigations have not only broadened the scientific basis for the rational use of phytotherapeutics but have also provided evidence for their therapeutic efficacy and favourable safety profile.
Androgen Antagonists↗
The case for teaching history to student nurse anesthetists.
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Curriculum↗
Metal-insulator transitions: influence of lattice structure, jahn-teller effect, and Hund's rule coupling
We study the influence of the lattice structure, the Jahn-Teller effect, and the Hund's rule coupling on a metal-insulator transition in A(n)C60 (A = K,Rb). The difference in the lattice structure favors A3C60 (fcc) being a metal and A4C60 (bct) being an insulator, and the coupling to H(g) Jahn-Teller phonons favors A4C60 being nonmagnetic. The coupling to H(g) ( A(g)) phonons decreases (increases) the value U(c) of the Coulomb integral at which the metal-insulator transition occurs. There is an important partial cancellation between the Jahn-Teller effect and the Hund's rule coupling.
Journal Article↗
Representations of dread: the dreaded self and the dreaded state of the self.
The experience of dread, an extreme form of fear that is induced by terror and horror, is seen as manifested in the shapes of a "dreaded self" and a "dreaded state of the self." These representations reflect psychic dangers ranging from a common, feared identification to states of disconnection, desolation, ego dissolution, and nonexistence. It is suggested that life crises and traumatic impingements, informed by developmental and psychic realities, are critical determinants of multiple dreaded self-representations; that disavowal often serves to massively ward off the recognition of the awful; and that these representations serve a preconscious signal function that anticipates the danger of reexperiencing an original terror. Case examples illustrate these points and reflect the utility of the language of dreaded representations in the treatment situation.
Adult↗
Evidence for immunotoxic effects of crude Ginkgo biloba L. leaf extracts using the popliteal lymph node assay in the mouse.
Allergic reactions due to contact with different parts of the ancient tree Ginkgo biloba L. have repeatedly been reported. Provocation tests in patients and animal experiments have identified alkylphenols such as ginkgolic acids as causative constituents. Leaf extracts from Ginkgo are widely used to treat peripheral or cerebral circulatory disorders and Alzheimer's disease. Since alkylphenols are also present in leaves, potential allergic and other immunological hazards of such preparations have to be carefully controlled. Thus, we have evaluated if the popliteal lymph node assay (PLNA) in the mouse may represent a suitable model for the detection of constituents with immunotoxic properties in a complex mixture of biologically active agents such as plant extracts. Subplantar injection (2 mg) of a crude aqueous-ethanolic extract from Ginkgo leaves caused a significant lymphoproliferative reaction (LPR) in the ipsilateral popliteal lymph node. PLNA-active compounds in this extract could be enriched in the lipophilic phase by liquid-liquid partition between heptane and water. Chemical analysis of the heptane extract revealed the presence of a high concentration of alkylphenols (approx. 30%) and further subfractionation indicated that the enlargement of the popliteal lymph node was mainly due to the content of ginkgolic acids. This presumption was corroborated by observing a similar LPR following injection of a purified mixture of ginkgolic or hydroginkgolic acids. Thus, our experiments confirm that Ginkgo leaf extracts may contain constituents with immunotoxic properties, underlining the need to apply adequate production procedures to guarantee the completest possible removal of these compounds. The PLNA appears to represent a simple test model for the detection, characterisation and control of ingredients with potential immunotoxic side effects in complex herbal drugs.
Animals↗
Minimal surfaces with self-intersections along straight lines. II. Surfaces forming three-periodic labyrinths.
47 families of minimal surfaces with straight self-intersections have been derived which subdivide R3 into a finite number of congruent three-periodic labyrinths. In most of these cases, namely for 42 families, the number of labyrinths is two. Four congruent labyrinths have been found three times and eight congruent labyrinths twice. Minimal surfaces with three or six labyrinths seem not to exist. Most of these minimal surfaces are non-orientable. The surfaces of three families only are orientable ones.
Journal Article↗
Minimal surfaces with self-intersections along straight lines. I. Derivation and properties.
A special kind of three-periodic minimal surface has been studied, namely surfaces that are generated from disc-like-spanned skew polygons and that intersect themselves exclusively along straight lines. A new procedure for their derivation is introduced in this paper. Several properties of each such surface may be deduced from its generating polygon: the full symmetry group of the surface, its orientability, the symmetry group of the oriented surface, the pattern of self-intersections, the branch points of the surface, the symmetry and periodicity of the spatial subunits demarcated by the surface, and the Euler characteristics both of the surface and of the spatial subunits. The corresponding procedures are described and illustrated by examples.
Journal Article↗
Bioavailability of ginkgolides and bilobalide from extracts of ginkgo biloba using GC/MS.
The bioavailability of ginkgolides A, B and bilobalide was studied in rats after single oral administration of 30, 55 and 100 mg/kg Ginkgo extract EGb 761. The plasma levels of the terpene lactones were measured by a specific GC/MS method. The pharmacokinetics of the mentioned substances were found to be dose-linear. For the lowest dose maximum concentrations were 68, 40 and 159 ng/ml and half-lives 1.7, 2.0 and 2.2 h for ginkgolide A, B and bilobalide, respectively. Clearance values ranged from 24.2 to 37.6 ml/min/kg.
Animals↗
Alice Magaw and the great secret of open drop anesthesia.
With this issue of the AANA Journal, "Imagining in Time" begins an occasional series that will reprint historical articles written by early and pioneer nurse anesthetists. The purpose is to keep the past alive and stimulate research interest. A brief commentary will accompany each article and, whenever possible, a bibliography will be included. Appropriately, the series commences with the "Mother of Anesthesia," Alice Magaw, CRNA (1860-1928), who wrote five articles between 1899 and 1906. Featured is a reprint of Magaw's fifth article titled "A review of over fourteen thousand surgical anesthesias," which was published in a 1906 issue of Surgery, Gynecology and Obstetrics.
Anesthesia, General↗
[Brief report of working group OPD-CA (children and adolescents) Axis IV: structural standard].
Apart from the structural differentiation of the body and its functions, the enlargement of the child's repertoire of possibilities to make experiences and to act is a manifestation of the development of the child's psychic structure which, advancing in years, may be considered as a treasure of all the experiences one has made with oneself, with the world and with the others. Structure will develop along with the interactional experiences with the world around us and becomes manifest in one's behaviour which may be witnessed and observed. The description of the psychic structure comprises three dimensions (perception of the self and of the objects, control, communication and bonding) which will be described by certain capabilities and will be assessed with the help of an anchoring example typical for each age which serves the purpose of clinical illustration. The adaptational achievement may then be assessed on the basis of a structural standard independent of age and may be ranged on a structural level. It appears that the exemplary description of different scopes of tasks typically to be performed at certain ages which serves as a basis for the assessment of the adaptational competence during childhood and adolescence seems to be a good policy. The purpose of our studies is the development of a valid instrument which is easy to handle in practice and which has a high interrater-reliability.
Adolescent↗
Crystallization in Polyamide 6/Polysulfone Blends: Effect of Polysulfone Particle Size.
By reactive blending of polyamide 6 (PA) with polysulfone (PSU) using a gram-scale mixer (Mini-Max Molder), we prepared a series of PA/PSU (80/20 wt.ratio) with various diameters of PSU particles: 90 nm by using phthalic anhydride-terminated PSU (PSU-PhAH), 0.2 µm by carboxylic acid-grafted PSU (PSU-COOH), and 1.0 µm by nonreactive PSU (nf-PSU). Isothermal crystallization was carried out at 200 degreesC. Light scattering studies showed that spherulites in the blends can grow to more than 10 µm in diameter, as in the case of neat PA. It suggests that crystal growth in the radial direction can be achieved by circumventing the PSU obstacles; i.e., it does not matter how big or small they are in the range of 90 nm to 1 µm. The smaller the PSU particles, the slower was the overall rate of crystallization. The slower rate may be caused by the higher population of brush PA chains attached to PSU particles as block or graft chains, since the brushes may be hard to organize into crystal lamellae, compared with free chains. The blends showed rather broad wide-angle X-ray diffraction profiles. The smaller the PSU particles, the broader was the profile. The scattering from the particles themselves should appear only at extremely low angles (<0.1 degrees) and hardly affects the wide-angle X-ray profiles so that the results may imply that the presence of smaller PSU particles renders the less perfection of the PA crystal. This may be caused also by the higher population of brush chains. Note that the brush chains are formed only in the reactive systems and the population may be higher in the smaller particle systems. Even for the blend with smallest particle size, a small-angle X-ray scattering peak appeared at a magnitude of scattering vector of approximately 0.8 nm-1, suggesting the evolution of interlamellar spacing of 8.7 nm. However, the scattering profile was much broader than that of neat PA. It implies a less ordered lamellar stacking in the blend.
Journal Article↗