Showing papers by "University of Münster published in 1986"

The Mathematics of Computerized Tomography

Abstract: The Mathematics of Computerized Tomography covers the relevant mathematical theory of the Radon transform and related transforms and also studies more practical questions such as stability, sampling, resolution, and accuracy. Quite a bit of attention is given to the derivation, analysis, and practical examination of reconstruction algorithm, for both standard problems and problems with incomplete data.

Hepatitis B virus DNA integration in a sequence homologous to v-erb-A and steroid receptor genes in a hepatocellular carcinoma.

Abstract: Hepatitis B virus (HBV) is clearly involved in the aetiology of human hepatocellular carcinoma (HCC) and the finding of HBV DNA integration into human liver DNA in almost all HCCs studied suggested that these integrated viral sequences may be involved in liver oncogenesis. Several HBV integrations in different HCCs and HCC-derived cell lines have been analysed after molecular cloning without revealing any obvious role for HBV. From a comparison of a HBV integration site present in a particular HCC with the corresponding unoccupied site in the non-tumorous tissue of the same liver, we now report that HBV integration places the viral sequence next to a liver cell sequence which bears a striking resemblance to both an oncogene (v-erb-A) and the supposed DNA-binding domain of the human glucocorticoid receptor and human oestrogen receptor genes. We suggest that this gene, usually silent or transcribed at a very low level in normal hepatocytes, becomes inappropriately expressed as a consequence of HBV integration, thus contributing to the cell transformation.

Use of Hepes buffer for microalgal culture media and fixation for electron microscopy

Abstract: N-2-hydroxyethylpiperazine-N-2′-ethanesulfonic acid (Hepes) has been tested as an alternative to tris-(hydroxymethyl)aminoethane (Tris) for hydrogen-ion buffering of algal cultures. Hepes satisfactorily buffered both freshwater and artificial seawater media and has been used successfully to grow 25 species of microalgae from five classes. Electron microscopic fixations of Tetraselmis striata Butcher (Prasinophyceae) and Amphidinium rhyncocephalum Anissimowa (Dinophyceae) buffered by Hepes have given far superior ultrastructural preservation than fixations buffered by Tris. The substitution of Hepes for Tris allows a defined seawater medium to be used as a fixative vehicle for the first time.

Comparison between Simultaneously Recorded Auditory-Evoked Magnetic Fields and Potentials Elicited by Ipsilateral, Contralateral and Binaural Tone Burst Stimulation

Abstract: Both auditory-evoked magnetic fields (AEMF) and auditory-evoked potentials (AEP) mainly consist of three peaks with latencies of about 50, 100 and 160 ms. Comparison of responses to ipsilateral, contralateral and binaural stimulation yields no significant amplitude or latency differences of the AEP peaks whereas the simultaneously recorded AEMF peaks exhibit a 10 ms shorter latency and an approximately 38% greater amplitude for contralateral versus ipsilateral stimulation. This fact can be due to differences in the strength, location (especially the depth) and the direction of the dipole source, and a decision cannot be made considering the data recorded from just one position. Another finding is that binaural stimulation reduces the peak amplitudes by approximately 25% compared with contralateral stimulation. This result indicates some kind of interference between the ipsilateral and contralateral pathways ('binaural interaction').Les champs magnetiques evoques auditifs (CMEA) et les potentiels evoques a...

Chromatographic Resolution of Chiral Drugs on Polyamides and Cellulose Triacetate

Abstract: Many chiral drugs are resolved very efficiently by chromatography on optically active polyamides and microcrystalline cellulose triacetate. These adsorbents having a wide range of applications can be used repeatedly on an analytical as well as on a preparative scale without losing their resolution efficiency.

DNA stemline heterogeneity in colorectal cancer.

Abstract: The current study was carried out on 88 colorectal carcinomas to assess the degree of intratumor heterogeneity as reflected by multiple aneuploid DNA stemlines and their relation to tumor stage and morphologic differentiation. Each tumor was segregated into an average of nine specimens (3–15), which were analyzed separately. DNA aneuploidies were identified in 72 cases (82%), 29 revealing multiple aneuploid DNA stemlines with up to four aneuploid subpopulations. In 10 of the 29 carcinomas with DNA stemline heterogeneity, a ratio of 2:1 was calculated from the different DNA indices, possibly indicating that the additional DNA stemline emerged from the first one by doubling its DNA content. No correlation was found between the overall frequency of DNA aneuploidies or heterogenous DNA stemlines and the tumor stage according to Dukes' staging. Well-differentiated carcinomas tended to express aneuploid DNA stemlines more frequently than moderately or poorly differentiated tumors, although the morphologic, intratumor heterogeneity did not correspond to the appearance of multiple aneuploid DNA stemlines. These data indicate a high degree of intraneoplastic diversity in colorectal cancer and emphasize the usefulness of DNA analyses for the quantitative assessment of tumor heterogeneity. Cancer 58:258–263, 1986.

Cutaneous manifestation of lethal genes.

Abstract: Several multisystem birth defects are associated with widespread skin lesions arranged in a pattern following the lines of Blaschko (1901). Some of these disorders are transmitted by X-linked dominant genes, and therefore the systematized cutaneous:lesions can be explained by the Lyon effect of random X-inactivation, visualizing the dorsoventral outgrowth of two functionally different populations of cells during early embryogenesis (Happle 1985). In other syndromes displaying skin defects arranged in a similar pattern, there is no evidence of a hereditary basis since all cases are sporadic. Among these sporadic disorders one groups also the McCune-Albright syndrome which is characterized by fibrous bone dysplasia arranged in a scattered and asymmetric distribution, endocrine dysfunction, and systematized linear pigmented skin lesions. In the past, the origin of the disorder was unexplained. Recently, it has been argued that the variable and multifaceted features of this syndrome are probably due to the action of a lethal gene surviving by mosaicism (Happle 1986). Here, the same mechanism of origin is proposed to apply to two other birth defects, implying a more general significance of the concept. The Schimmelpenning-Feuerstein-Mims syndrome consists of ocular anomalies including coloboma, cerebral defects such as mental retardation or seizures, and a systematized linear sebaceous nevus following the lines of Blaschko (Hornstein and Knickenberg 1974; Bouwes Bavinck and van de Kamp 1985). All cases are sporadic, and this is best explained by the assumption of a dominant lethal gene, killing the zygote in utero. Cells bearing the mutation would only be able to survive in a mosaic state, in close proximity with normal cells. This mosaicism may result either from an early somatic mutation, or from a gametic half chromatid mutation as first proposed for the occurrence of incontinentia pigmenti in males (Lenz 1975). The Proteus syndrome is characterized by partial gigantism of the hands or feet, hemihypertrophy, macrocephaly or other skull anomalies, subcutaneous mesodermal tumors, and systematized nevoid skin lesions (Wiedemann et al. 1983). Histopathologically, the cutaneous changes have been found to be a papillomatous epidermal nevus (Burgio and Wiedemann 1984). Clinical photographs show that the lesions follow the lines of Blaschko (Wiedemann et al. 1982; Mticke et al. 1985).

Priapism: a three-phase concept of management according to aetiology and prognosis.

Abstract: Summary— Priapism is a persistent, painful erection of the penis unassociated with sexual stimulation or desire, and detumescence does not occur following ejaculation. Prolonged pathological erections may occur and it is only when they are painful that the term priapism should be used. The erection is limited to the corpora cavernosa. Although the syndrome was named after Priapos, the mythical Greek god of fertility, impotence persists in one half of patients treated for priapism. The disease is rare; the literature consists mainly of case reports and comprehensive reviews are seldom found. Permanent sequelae cause a psychological and physical handicap and justify the present review, which is based upon recent literature as well as personal clinical experience of 15 patients. We have reviewed 170 reports describing 1400 cases of priapism and have based the analysis upon the 230 single case reports found in the literature.

Sperm-Egg Fusion

Abstract: Proteinaceous “Sperm Receptors” on the egg plasma membrane facilitate binding of sperm (Wolf et al., 1976). The inability of trypsin inhibitors to prevent binding of mouse sperm to eggs (Saling, 1981) suggests that acrosin activity is not required for gamete contact, but Ca2+ is necessary for sperm-egg contact in both hamsters (Yanagimachi, 1982) and mice (Saling, 1981).

Oxygen uptake of microorganisms entrapped in Ca-alginate

Abstract: The oxygen uptake rates of Pseudomonas putida, Saccharomyces cerevisiae and Aspergillus niger, immobilized in Ca-alginate gel, were determined in comparison with the respiration of free cells. The specific oxygen uptake rate of immobilized microorganisms decreased with increasing cell content of the gel beads and increasing alginate concentration.

A monoclonal antibody against an antigen present on mouse macrophages and absent from monocytes.

Abstract: A monoclonal antibody (BM8) raised in the rat against cultured mouse bone marrow-derived macrophages reacted only with macrophages and not with granulocytes, mast cells, platelets, lymphocytes, fibroblasts, and endothelial cells. BM8 did not detect blood monocytes. In cultured bone-marrow cells, expression of BM8-antigen was found on a few macrophages after one day of culture and reached its maximum level with 80% positive macrophages after 7-10 days of culture. The antibody BM8 belonged to the IgG2a subclass, was non-cytotoxic and directed against a 125 kD membrane antigen. In cryostat sections of normal mouse tissues (spleen, lymph node, thymus, liver, skin) BM8 detected tissue-fixed macrophages and Langerhans cells in the skin. In spleen and lymph node, BM8 reacted with macrophages in the red pulp and in the medullary cords, respectively, but not with heavily phagocytosing marginal-zone macrophages, as revealed by in-vivo phagocytosis of colloidal carbon. In granulomata induced by complete Freund's adjuvant, BM8 detected inflammatory macrophages but not epithelioid cells. Thus, antibody BM8 detected a differentiation antigen expressed only on mature, tissue-fixed macrophages.

Ternary carbides of the rare earth and iron group metals with CeCoC2- and CeNiC2-type structure

Abstract: 32 carbides RTC2 (R ≡ rare earth metal, T ≡ Fe, Co, Ni), 18 for the first time, were prepared by arc melting of the elemental components and subsequent annealing in evacuated silica tubes. Most of them crystallize in the orthorhombic CeNiC2-type structure. The carbides LnCoC2 (Ln ≡ La, Ce, Pr, Nd) have the related monoclinic CeCoC2-type structure. SmCoC2 is of CeCoC2 type at low temperature and of CeNiC2 type at high temperature. The crystal structures of DyCoC2 and DyNiC2 were refined from singlecrystal X-ray data to residuals of R = 0.012 (581 structure factors) and R = 0.023 (971 structure factors) for 17 variable parameters. The carbon atoms in these compounds form pairs. The C-C distances of 1.37 A come close to the double bond distances of 1.34 A in alkenes. The hydrolysis of DyCoC2 in diluted hydrochloric acid, however, yields only little ethene, mainly ethane and some propane and methane. The cell volumes indicate that cerium and ytterbium are essentially trivalent in these compounds, whereas the corresponding europium compounds cannot be prepared under similar conditions.

Distribution of the [3H]-label from low doses of radioactive ochratoxin a ingested by rats, and evidence for DNA single-strand breaks caused in liver and kidneys

Abstract: The distribution of a single low dose of [3H]ochratoxin A (OTA) in different tissues of male Wistar rats, after administration by intubation, was investigated after 5 h, 24 h and 48 h This dose corresponds to concentrations encountered in naturally contaminated feed (4 ppm) The distribution of [3H]-label varied with the time elapsed after administration; at 5 h the highest specific label was found in the stomach contents and in decreasing order in: intestinal contents, lung, liver, kidney, heart, fat, intestine, testes, and the lowest in muscles, spleen and brain With exception of brain, fat, stomach and lung, all tissues showed maximum levels at 24 h, after which time the label decreased steadily, whereas in fat it increased After a 12-week feeding experiment, with doses of 2888 μg/kg corresponding to an intake of 4 ppm in feed each 48 h, the DNA in liver and kidneys was investigated for damage By the alkaline elution method combined with micro-spectrofluorimetric determinations of DNA, evidence for DNA single-strand breaks was obtained These findings support reports on the carcinogenic action of OTA

Ichthyosis bullosa of Siemens: a unique type of epidermolytic hyperkeratosis

Abstract: We report the second family of ichthyosis bullosa, an entity that was first described by Siemens in 1937 and since then has fallen into oblivion. Clinically, ichthyosis bullosa is characterized by blistering resembling epidermolysis bullosa simplex and by generalized, yet circumscribed dark gray hyperkeratoses covering mainly the arms and the legs. Lichenification and superficially denuded areas (mauserung) are further prominent features. Histology disclosed intracomeal blister formation corresponding to the mauserung phenomenon and epidermolytic hyperkeratosis that was confined to the granular layer and to the uppermost layers of the prickle cells. On electron microscopic examination the keratinocytes of these layers displayed structural alterations of tonofilaments as usually observed in epidermolytic hyperkeratosis. Thus ichthyosis bullosa shares with bullous ichthyosiform erythroderma blistering and epidermolytic hyperkeratosis, but can be distinguished from this wellknown disease by the lack of erythroderma, by the mauserung phenomenon, by the confinement of acanthokeratolysis to the superficial layers of the epidermis, and by intracorneal blistering.

Topical immunotherapy changes the composition of the peribulbar infiltrate in alopecia areata.

Abstract: It has previously been shown that, in patients with untreated progressive alopecia areata (AA), the peribulbar T4/T8 ratio is about 4:1. In the present study, the immunohistochemical findings obtained in untreated AA patients were compared to those obtained in patients who had received topical immunotherapy with diphencyprone. The untreated group consisted of 5 patients with progressive AA and 5 patients with inactive AA. The treated group consisted of 5 patients with a good response to diphencyprone and 5 patients with little or no hair regrowth after treatment. In untreated patients with progressive AA, the mean peribulbar T4/T8 ratio was 4:1, whereas in untreated patients with stable AA, the ratio was 2:1. In the treated patients with a good response to diphencyprone, the mean T4/T8 ratio was 1:1, while in the patients with poor or no response to treatment, the ratio was 0.7. In conclusion, topical immunotherapy considerably alters the peribulbar T4/T8 ratio in AA. The results are consistent with, but do not prove, the concept of topical immunomodulation.

Synthesis and properties of polyurethanes derived from diaminodianhydroalditols

Abstract: The readily accessible 1,4:3,6-dianhydroalditols with D-gluco- (1), L-ido- (5) and D-mannoconfigurations (6) were efficiently transformed into the 2,5-diamino-1,4:3,6-dianhydro-2,5-dideoxyalditols with D-gluco- (10), D-manno- (13), and L-ido-configuration (16). Interfacial polycondensation of these chiral heterocyclic diamines as well as ethylene- and tetramethylene diamine with the bis(chloroformate) 3 derived from 1,4:3,6-dianhydro-D-sorbitol gave the polyurethanes 17 to 21. Their number-average molecular weights were determined to be Mn ≈ 3000 corresponding to an average degree of polymerisation Pn ≈ 20. Inherent viscosities were measured, and 1H NMR spectroscopy as well as DSC gave informations about the molecular structure and some polymer properties.

Localization of collagen types I, III, IV and V, fibronectin and laminin in human arteries by the indirect immunofluorescence method.

Abstract: The distribution of types I, III, IV and V collagen and of the glycoproteins fibronectin and laminin in sections of human aortas, arteries and atherosclerotic plaques were studied using monospecific antibodies and indirect fluorescence microscopy. Types IV and V collagen and laminin were present in a narrow zone, representing the basement membrane, apposed to the endothelial layers of all these tissues. Types I and III collagen and fibronectin were located in the interstitial spaces of the intima and the media of blood vessels walls, whereas types IV and V collagen and laminin were found in the basement membranes underlying smooth muscle cells in these areas. Two types of atherosclerotic plaques were observed. Lipid-rich plaques contained less collagen and reduced amounts of the glycoproteins. Fibrous plaques consisted of regions deficient in types I and III collagen and collagen-rich regions with elevated levels of these two collagens as well as more fibronectin. The collagen-rich regions of fibrous plaques contained, however, little type IV and type V collagen and little of the glycoproteins laminin and fibronectin. This may be due to the reduced number of cells involved in the biosynthesis of these basement membrane proteins.

Elicitation and Suppression of Phytoalexin and Isoflavone Accumulation in Cotyledons of Cicer arietinum L. as Caused by Wounding and by Polymeric Components from the Fungus Ascochyta rabiei

Abstract: Shortly after sowing cotyledons of chickpea (Cicer arietinum) start to accumulate the isoflavones biochanin A and formononetin together with their 7-0-glucosides and their 7-0-glucoside-6″-malonates. The additional accumulation of the pterocarpan phytoalexins medicarpin and maackiain can be induced by wounding of the cotyledons. Treatment of sliced cotyledons with a crude elicitor fraction obtained from the growth medium or the mycelium of the chickpea pathogenic fungus Ascochyta rabiei (Pass.) Lab. leads to a dramatic increase in the level of numerous aromatic compounds, especially of the isoflavone aglyca and the phytoalexins. Accumulation of isoflavone conjugates is not altered by elicitor treatment as shown by time course studies, and dose-response curves. A protein preparation (“suppressor”) isolated from the culture filtrate of the same fungus was shown to inhibit the accumulation of isoflavone aglyca, isoflavone conjugates and phytoalexins in the sliced cotyledons. The possible relevance of elicitor-suppressor counteraction with regard to the defence mechanisms of the host plant is discussed. Zusammenfassung Auslosung und Hemmung der Phytoalexin- und Isoflavonakkumulation in Kotyledonen von Cicer arietinum L. durch Verwundung und polymere Substanzen aus dem Pilz Ascochyta rabiei . Kurz nach Aussaat beginnen die Kotyledonen der Kichererbse (Cicer arietinum L.) mit der Akkumulation der Isoflavone Biochanin A und Formononetin sowie ihrer 7-0-Glukoside und ihrer 7-0-Glukosid-6″-Malonate. Die zusatzliche Akkumulation der Pterocarpan Phytoalexine Medicarpin und Maackiain kann durch Zerschneiden der Kotyledonen induziert werden. Behandlung zerschnittener Kotyledonen mit einer Elicitorpraparation aus dem Nahrmedium oder dem Myzel des fur die Kichererbse pathogenen Pilzes Ascochyta rabiei (Pass.) Lab. fuhrt zur Akkumulation zahlreicher aromatischer Verbindungen, besonders der Isoflavonaglyka und der Phytoalexine. Die Akkumulation der Isoflavonkonjugate wird durch Elicitorbehandlung nicht beeinflust. Eine Proteinpraparation („Suppressor”) aus dem Nahrmedium von A. rabiei hemmt in den zerschnittenen Kotyledonen die Akkumulation der Isoflavonaglyka, der Isoflavonkonjugate und der Phytoalexine. Die mogliche Bedeutung des Elicitor-Suppressor-Systems fur die untersuchte Wirt-Parasit- Beziehung wird diskutiert002

Mating types and mating inducing substances in Euplotes octocarinatus

Abstract: The complex pattern of reactions between cells of ten different mating types of Euplotes octocarinatus, a fresh water ciliate closely related to E. patella, is reported. Mixture of cells of two different types leads in the majority of combinations to the formation of both heterotypic and homotypic pairs after a waiting period of about 3 hours. In a few combinations only homotypic pairs of one of the two mixed types are formed. Both homotypic and heterotypic pairs undergo meiosis and complete conjugation. Cross breeding experiments show that the ten mating types are determined by four codominant alleles (mt1, mt2, mt3, and mt4) that control the production of four matinginducing signal-substances or gamones (G1, G2, G3, and G4). These substances are secreted into the medium and induce mature cells of certain other mating types to transform into cells that are able to unite and form conjugant pairs. We suggest that the transformation of the cells into cells ready for conjugation is triggered by the binding of gamone molecules to gamone-specific receptors and that mature cells usually expose receptors for all gamones except the ones they produce themselves.

Actions of pentylenetetrazol (PTZ) on CA3 neurons in hippocampal slices of guinea pigs.

Abstract: The actions of the convulsant drug pentylenetetrazol (PTZ) were studied on CA3 neurons of hippocampal slices (300–400 μm thick). In 9 out of 109 neurons, epileptic reactions were elicited during a single application of PTZ. After repeated applications of PTZ, 53 neurons showed periodic paroxysmal activity. They developed according to the following sequence: (i) Paroxysmal hyperpolarizations, (ii) burst activity, and (iii) typical paroxysmal depolarization shifts (PDS). The rate of occurrence was about 8/min. Paroxysmal hyper- and depolarizations appeared synchronously in pairs of neurons. The developmental sequence occurred in reverse during washing. After the onset of paroxysmal activity, bursts and PDS persisted if PTZ concentration in tissue ranged between about 2 and 10 mmol/l. When this range was exceeded in either direction, epileptic activity was abolished at a calcium concentration of 2.75 mmol/l. Decreasing and increasing the calcium concentration shifted the epileptogenic concentration range to lower and higher levels, respectively. It is concluded that repetition of PTZ application alters membrane properties of neurons and thus leads to paroxysmal events triggered by synaptic processes.