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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 15 (1970), S. 359-362 
    ISSN: 1432-0533
    Keywords: Ependymoma ; Polygonal Crystalline Structures ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Polygonale kristalline Strukturen fanden sich in Lysosomen der Zellen eines menschlichen Ependymoms. Die von der granulären Matrix der Lysosomen gut abgegrenzten Strukturen waren aus regelrecht in Abständen von 150–160 Å angeordneten Formationen aufgebaut, in denen dichte und weniger dichte Schichten abwechselten. Diese waren in einer der drei Achsen angeordnet und bildeten rechteckige, tetragonale oder hexagonale Gebilde.
    Notes: Summary Polygonal crystalline structures were found in the lysosomes of human ependymoma cells, well demarcated from the granular matrix of the lysosomes. They were composed of a regular spacing at an interval of 150–160 Å of alternating dense and less dense layers, orientated along one to three axes and forming rectilinear, tetragonal, or hexagonal arrays.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 15 (1970), S. 114-127 
    ISSN: 1432-0533
    Keywords: Opticoacoustic Nerve Degeneration ; Polyneuropathy ; Hypertrophic Changes ; Nerve Biopsy ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Es werden die elektronenmikroskopische Befunde der Nervenbiopsie eines Patienten mit familiärer optikoakustischer Nervendegeneration und Polyneuropathie mitgeteilt. Diese Krankheit, die noch nicht klinisch abgerenzt ist, ähnelt der Charcot-Marie-Tooth-Krankheit wie auch der Refsumschen Krankheit. Eine hypertrophische Neuropathie mit Zwiebelschalenstrukturen wurde festgestellt. Die Zwiebelschalenstruktur erscheint oft bedingt durch eine abnorme Verlängerung der Schwann-Zellbasalmembran, die manchmal den Zwiebelschalenkern ringförmig einwickelt. Es wurden auch Degeneration der Markscheide und des Achsencylinders, unbedeutende Remyelinisierungsvorgänge und unspezifische Lipoid-Ablagerungen im Cytoplasma der Schwann-Zellen beobachtet. Abnorme Einschlüsse in den Schwann-Zellen, pathologische Ablagerungen im Endoneurium wie auch andere spezifische Befunde wurden nicht festgestellt. Die Befunde wurden als Frühveränderungen einer chronischen Neuropathie interpretiert.
    Notes: Summary Electron microscopic data are presented on a sural nerve biopsy from a patient with familial opticoacoustic nerve degeneration with polyneuropathy. This disease is not yet defined clinically, but is similar to Charcot-Marie-Tooth disease and Refsum's disease. Examination showed a hypertrophic neuropathy with onion-bulb formations. There was often abnormal elongation or an occasional circle of the basement membrane of a Schwann cell around the core of the onion-bulb. Degeneration of the myelin sheath and the axon, very rare remyelinative changes, and non-specific lipid deposits in the Schwann cell cytoplasm were observed. Unusual inclusions in the Schwann cells or accumulations in the endoneurium were not observed. Specific findings were not found in this study. These findings were considered to be those of the early changes of a chronic neuropathy.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 14 (1970), S. 304-311 
    ISSN: 1432-0533
    Keywords: Electron Microscopy ; Plaques Fibromyéliniques ; Ulegyria and Status Marmoratus ; Myelinated Astrocyte-like Processes ; Hypermyelinization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé Le cas d'un garçon âgé de 12 ans avec antécédant traumatique périnatal et porencéphalie encéphaloclastique est rapporté. L'étude au microscope électronique de zônes d'ulégyrie et d'état marbré montrent que les plaques fibromyéliniques présentes dans ces régions sont essentiellement constituées de prolongements fibrillaires d'origine probablement astrocytaire, entourés de lamelles myéliniques. L'hypermyélinisation de certains de ces prolongements est également présente. Ces observations plaident en faveur d'une activité régénératrice excessive de la part des cellules gliales myélinoformatrices.
    Notes: Summary A 12 year old boy with a history of perinatal injury resulting in encephaloclastic porencephaly is described. Electron microscopic examination of the plaques fibromyéliniques in areas of ulegyria and status marmoratus revealed that they mainly consist of fibrillated processes, apparently of astrocytic origin, surrounded by myelin lamellae. Hypermyelinization of some of these processes was also present. These observations suggest excessive regenerative activity on the part of myelin-forming glial cells.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-0533
    Keywords: Subacute Myelo-Optico-Neuropathy ; Peripheral Nerve ; Muscle ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Von einem Patienten mit peripherer Nervenlähmung, die einer schweren Diarrhoe folgte, wurden Biopsien vom N. suralis und vom M. quadriceps femoris elektronenmikroskopisch untersucht. Die Markscheiden der peripheren Nervenfasern waren geschwollen und in Degeneration begriffen. Die Axone der markhaltigen Nervenfasern zeigten beginnende Degeneration; auch an den Schwannschen Zellen wurde Degeneration beobachtet. Bemerkenswerte Befunde am Muskel waren Unregelmäßigkeiten des Z-Bandes und Verschwinden der dicken Fasern. In allen Teilen der Muskel waren die Glykogengranula beträchtlich vermehrt. Diese Befunde zeigen, daß im vorliegenden Fall nicht nur die peripheren Nerven, sondern auch die Muskeln geschädigt worden waren. Die Muskelveränderungen stellen einen neuen Befund bei subakuter myelo-optischer Neuropathie dar.
    Notes: Summary N. suralis and M. quadriceps femoralis, taken from a patient with peripheral nerve paralysis following severe diarrhoea, were examined by electron microscopy. In the nerve fibres myelin sheaths were swollen and degenerated: axons in myelinated fibres also were degenerated. Degeneration was also observed in Schwann cells. In muscle the noteworthy findings were focal irregularity of Z-bands and disappearance of thick filaments. In all parts of the muscle, glycogen granules were remarkably increased in number. These findings reveal that in the present case there was damage not only to peripheral nerve but also to muscle. The changes in the muscle are a new observation in subacute myelooptico-neuropathy.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 16 (1970), S. 233-242 
    ISSN: 1432-0533
    Keywords: Electron Microscopy ; Sural Nerve ; Arsenical neuropathy ; Wallerian Degeneration ; Onion Bulb
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Es werden die elektronenmikroskopischen Beobachtungen und Zupf-befunde an der Nervenbiopsie eines Patienten mit Arsenneuropathie mitgeteilt. Die Zupf-methode und die mit Toluidinblau gefärbte Epon-präparate zeigten eine Verminderung der markhaltigen Achsencylinder und Veränderungen nach Art der Wallerschen Degeneration. Elektronenmikroskopische Befunde zeigten Markscheidenzerstörungen mit Achsencylinder-degeneration und Verlust bemarkter Axone sowie häufige degenerative Veränderungen im Cytoplasma der Schwann-Zellen. Keine Hinweise auf segmentale Demyelinisation, aber seltene zwiebelschalenähnliche Strukturen mit Schwann-Zellproliferation wurden beobachtet. Außerhalb der zwiebelschalenähnlichen Strukturen war keine wesentliche Verbreitung der Basalmembran und Vermehrung von Kollagenfasern sowie keine Phagocytose vorhanden. Diese Befunde werden im wesentlichen als Folge der Wallerschen Degeneration betrachtet. Es werden einige Betrachtungen über die ungewöhnlichen zwiebelschalenähnlichen Strukturen angestellt.
    Notes: Summary Examination of electron microscopical and teased preparations of a biopsied sural nerve from a patient with arsenical neuropathy is reported. Teased preparations and toluidine blue stained epon sections showed a decrease in the number of myelinated fibres and Wallerian degeneration. Electron microscopy revealed destruction of myelin sheaths, further disintegration associated with degeneration or disappearance of myelinated axons and numerous degenerative changes in the Schwann cell cytoplasm. There was no evidence of segmental demyelination. Occasional onion-bulb-like structures, however, associated with proliferation of Schwann cells, were observed. Obvious elongation of the basement membrane, except in an onion-bulb-like structure, or collagen fibril proliferation or evidence of phagocytosis was not found. These findings are considered to correspond mainly with Wallerian degeneration. Some consideration as given to the unusual onion-bulb-like structures.
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  • 6
    ISSN: 1432-0533
    Keywords: Organic Mercury Compound ; Peripheral Nerve ; Minamata Disease ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Organische Quecksilberverbindungen schädigen im Nervensystem zunächst die peripheren Nerven. Dabei werden die sensiblen Fasern bevorzugt betroffen: es kommt zur Proliferation und Degeneration der Schwannschen Zellen sowie zu starken Veränderungen an Markscheiden und Axonen. Vermehrte Schwannsche Zellen und Makrophagen bewirken die Beseitigung und Verdauung degenerierter Markscheiden und Axone. Die Veränderungen an markhaltigen Nervenfasern beginnen hauptsächlich am Ranvierschen Schnürring. Organisches Quecksilber schädigt in einer bestimmten Dosierung ausschließlich die peripheren Nerven. Diese Befunde lassen vermuten, daß bei Patienten mit organischen Quecksilbervergiftungen mitunter nur Symptome von Schäden an sensiblen Nerven auftreten können.
    Notes: Summary Organic mercury firstly affects peripheral nerves all over the nervous system. In peripheral nerves, pathological changes are selectively observed in sensory nerve fibres and are as follows: Swelling and degeneration of Schwann cells, noticeable changes in both myelin sheaths and axons. Proliferating cells such as Schwann cells and macrophages may be acting the role of removal and digestion of degenerated myelin and axon. The pathological changes in myelinated fibres tend to begin at the nodes of Ranvier. With the quantity of organic mercury which was administered, only peripheral nerves were injured. From this point of view, we speculate that, of the neurological signs, only sensory disturbance might be found in some of the patients poisoned by organic mercury.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 14 (1970), S. 261-283 
    ISSN: 1432-0533
    Keywords: Allergic Neuritis ; Electron Microscopy ; Mononuclear Cells ; Demyelination ; Remyelination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Kaninchen mit einer experimentell-allergischen Neuritis (EAN) wurden 8 Tage bis 4 Monate nach der Injektion einer Emulsion aus heterologem Nervengewebe mit Freundschem Adjuvans phasenkontrast- und elektronenmikroskopisch untersucht. Im akuten Stadium der Demyelinisation ist eine Beteiligung von mononucleären Infiltratzellen am Vorgang der Entmarkung peripherer Nervenfasern in der gleichen Weise nachweisbar, wie es Lampert (1969) bei der EAN von Ratten dargestellt hat. Da die Markscheidenschäden jedoch nicht immer in unmittelbarem Kontakt mit den Infiltratzellen auftreten, sind humorale Faktoren, die möglicherweise von den Infiltratzellen ausgeschieden werden, als Ursache der Markscheidenschäden nicht mit Sicherheit auszuschließen. Der weitere Abbau der geschädigten Markscheiden findet dann sowohl in den zu Makrophagen transformierten Infiltratzellen als auch in den proliferierenden Schwann-Zellen statt. Ausnahmsweise dominieren unter den Infiltratzellen auch bei der einfachen experimentell-allergischen Neuritis neutrophile Leukocyteninfiltrate; sie kommen in Zusammenhang mit anderen Zeichen einer schweren Störung der Gefäßnervenschranke wie Erythrodiapedesen und Fibrinexsudaten im fortgeschrittenen Stadium der Gewebsschädigung vor. Auf Axonläsionen und die im Ausheilungsstadium der EAN vorkommenden Zwiebelschalenformationen sowie die wiederholt beobachteten Gruppen regenerierter, von einer gemeinsamen Basalmembran gebündelter Nervenfasern wird kurz hingewiesen.
    Notes: Summary Rabbits with experimental allergic neuritis (EAN), induced by intradermally injected emulsified heterologous antigen together with Freund's adjuvant, were investigated by phase and electron microscopy 8 days to 4 months after the injection. Early lesions of the myelin sheaths in EAN can be demonstrated to occur in close contact with infiltrated mononuclear cells as has been reported by Lampert (1969) in rats. Yet since myelin lesions are not always restricted to areas of immediate contact with infiltrated mononuclear cells, it cannot be excluded that humoral factors, possibly excreted by the infiltrated cells, may initiate the myelin lesions. Further breakdown of myelin sheaths takes place in proliferating Schwann cells as well as in infiltrated mononuclear cells. Occasionally, neutrophilic leucocytes predominate among the cellular infiltrates. They occur together with erythrodiapedesis, and fibrinous exsudates in areas of severance of the blood-nerve barrier. Axonal lesions, and during remyelination, “onion bulb” formation were also seen as a sequence of the demyelinating lesions. Also, bundles of small regenerated nerve fibers enclosed by a single basement membrane were repeatedly observed in areas with remyelinated nerve fibers.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 15 (1970), S. 240-250 
    ISSN: 1432-0533
    Keywords: Ependymoma ; Electron Microscopy ; Secretory Granules ; Histochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Ein unikales Ependymom des Filum terminale mit intracytoplas-matischen Sekretgranula wurde licht- und elektronenmikroskopisch nachgewiesen. Auffallende strukturelle und histochemische Änlichkeiten bestehen zwischen den Sekretionsprodukten des Tumors und denen im sekretorischen System des Endabschnittes des Rückenmarks bei Fischen. Die Funktion und der Wirkungsort des Sekretionsproduktes sind unbekannt.
    Notes: Summary An unique ependymoma of the filum terminale with intracytoplasmic secretory granules has been identified by light and electron microscopy. A striking structural and histochemical similarity exists between the tumor secretory product and that found in the secretory system present in the terminal portion of the spinal cord of the fish. The function and site of action of the secretory product is unknown.
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  • 9
    ISSN: 1432-0533
    Keywords: Isolated Nerve Fibres ; Electron Microscopy ; Demyelination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Es wird eine Technik zur Isolierung peripherer Nervenfasern durch Auffasern und nachfolgende licht-undd elektronenmikroskopische Untersuchung beschrieben. Diese Technik wurde zum Studium ungewöhnlich geschwollener Fasern angewandt, die proximal der Läsion bei durchschnittenen Nerven von Ratten beobachtet wurden. Diese Fasern wurden als das Ergebnis der Demyelinisation bereits remyelinisierter Segmente dargestellt.
    Notes: Summary A technique is described for isolating peripheral nerve fibres by teasing and subsequently examining them by light and electron microscopy. The technique was applied to the study of unusual swollen fibres observed central to the lesion in transected nerves in rats. These were shown to be the result of the demyelination of already remyelinated segments of the fibre.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 15 (1970), S. 288-292 
    ISSN: 1432-0533
    Keywords: Electron Microscopy ; Kuru ; Inclusion ; Cytoplasmic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung In Fällen von Kuru wurden im Cytoplasma von ansonst normalen Purkinjezellen Strukturen mit strahlendichten Balkenmustern gefunden. Solche sind auch in geringerer Zahl im Axoplasma von Nervenfasern sowohl im menschlichen wie auch im Schimpansenmaterial vorhanden. Sie weisen eine zarte Punktstruktur auf sind und eng mit intracellulären Membranprofilen verbunden.
    Notes: Summary Within the cytoplasm of otherwise normal Purkinje cells barred structures have been found in cases of Kuru. They are also present in small numbers in axoplasm of nerver fibres, both in human and chimpanzee material. They present a discrete punctate structure and are closely associated with intracellular membranous profiles.
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  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 15 (1970), S. 327-350 
    ISSN: 1432-0533
    Keywords: Neuroaxonal Dystrophy Infantile ; Electron Microscopy ; Spheroids ; Smooth Endoplasmic Reticulum ; Mitochondria ; Seitelberger's Disease
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé Les auteurs rapportent 2 cas de DNAI.Le tableau clinique, d'évolution mortelle en 2 ans, associe un arrêt du développement psycho-moteur, des signes pyramidaux et extrapyramidaux, un nystagmus pendulaire avec atrophie optique. L'étude en microscopie optique définit:—les aspects morphologiques, la nature glycolipoprotéique et la répartition topographique des sphéroïdes, électivement disposés dans les structures médullaires, bulbo-protubérantielles et cérébelleuses, phylogénétiquement les plus anciennes, —l'atrophie du cortex cérébelleux, —la surcharge soudanophile avec état dysmyélinique du pallidum, —la dégénérescence des voies afférentes et efférentes des fibres longues de la moelle, du tronc cérébral et des voies optiques.L'étude en microscopie électronique précise la structure des sphéroïdes composés d'amas membrano-tubulaires et cisternaux, des corps denses amorphes ou lamellés, multigranuleux, pseudo-cristallins ou multivésiculaires et de mitochondries pathologiques. La formation de ce matériel est liée à l'hyperplasie du réticulum endoplasmique lisse et à l'accumulation de mitochondries anormales dans les péricaryons neuronaux, les prolongements dendro-axonaux, les culs de sacs synaptiques. Les auteurs rapprochent leurs constatations de faits semblables observés en pathologie humaine et expérimentale.
    Notes: Summary Two cases of INAD are reported. Clinical features with fatal issue within 2 years, are characterized by psychomotor retardation, pyramidal and extrapyramidal signs, pendular nystagmus with bilateral atrophia of optic discs.Light microscopy shows:—the morphology of spheroids, their glycolipoproteid component and their elective distribution in medulla, brain-stem and cerebellum, phylogenetically the oldest parts of the CNS—a cerebellar cortical atrophia—sudanophilic fatty deposits associated to status dysmyelinatus of pallidum—a degeneration of pyramidal, spinocerebellar tracts and optic pathways.Electron microscopy in the two cortical biopsies allows to specify the internal structure of spheroids made of membrano-tubular and interconnected aggregates, amorphous and lamellar electron-dense bodies, multigranular bodies, cristalline-like inclusions, multivesicular bodies and involved mitochondria. That complex material represents an overproduction of smooth endoplasmic reticulum and abnormal mitochondria located in neuronal perikarya, axons, dendrites and enlarged synaptic bulbs. These pathological findings are compared to those already described in human and experimental cases.
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  • 12
    ISSN: 1432-0533
    Keywords: Mental Deficiency ; Astrocytes ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung In einem Fall von Schwachsinn ohne starke somatische und neurologische Symptome wurde eine Biopsie der Frontalwindung vorgenommen und das Material elektronenmikroskopisch untersucht: Bei Fehlen eines cerebralen Abbauprozesses fanden sich Einschlußkörperchen im Cytoplasma der Astrocyten und eine abnorme Zunahme der Lipofuscingranula im Cytoplasma der Nevenzellen. Diese Einschlußkörperchen erwiesen sich aus geschädigtem ergastoplasmischen Reticulum und RNP-Körperchen bestehend. Aus diesen Befunden wurde geschlossen, daß die physiologische Funktion der Astrocyten infolge einer Störung des Protein-Metabolismus in den Astrocyten beeinträchtigt war; außerdem war die Funktion der Nervenzellen durch die Zunhme der Lipofuscingranula sekundär gestört. Es scheint, daß die Veränderungen eng mit dem Schwachsinn zusammenhingen und daß die intellektuellen Funktionen teilweise von der Funktion der Gliazellen abhängen.
    Notes: Summary A biopsy of a frontal gyrus from a case of idiocy, without gross bodily symptoms or neurological signs, was examined by electron microscopy. The results of this examination were as follows: there was no destructive process in the cerebral tissue but inclusions were seen in the cytoplasm of the astrocytes and there was an abnormal increase in lipofuscin granules, in the cytoplasm of the nerve cells. The inclusions consisted of damaged endoplasmic reticulum and RNP granules. From these findings, it was considered that the physiological function of the astrocytes was disturbed, as the result of a disturbance in protein metabolism and that the function of the nerve cells was also disturbed, with an increase in lipofuscin granules. These changes seem to be intimately concerned with mental deficiency and part of intellectual function seems to depend on the functions of the glia cells.
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  • 13
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 16 (1970), S. 161-172 
    ISSN: 1432-0533
    Keywords: Muscular Dystrophy ; Quadriceps Muscle ; Ring Fibres ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Eine Biopsie des M. vastus lateralis bei einem 49 jährigen Mann mit langsam progressiver Myopathie mit isoliertem Befall der Mm. quadriceps wurde untersucht. Es fanden sich zahlreiche atrophische Fasern und Ringbinden. Die atrophischen Fasern zeigten Zunahme an Glykogen und Mitochondrien sowie Verlust der Myofibrillen als geringere Läsionen sowie Fragmentierung und grobe Desorganisation der Myofilamente in den stärker betroffenen Fasern. Ausstülpungen der Basalmembran ragten aus ihrer Oberfläche vor. Phagocyten traten in wenigen degenerierten Fasern und in den Basalmembranschläuchen auf. Alle untersuchten Ringbinden hatten einen intakten Längskern mit einem eng anliegenden zirkulären Band von Myofibrillen. Schwere Veränderungen, wie sie in den atrophischen Fasern vorlagen, waren in den Ringbinden nicht anzutreffen. Die degenerativen Veränderungen beschränkten sich auf die umgebenden Myofibrillen, die Verlust der Myofilamente verschiedenen Grades sowie Anhäufungen von Glykogen und Mitochondrien aufwiesen. Die Verff. sind der Meinung, daß die Ringbinden originäre Strukturen und keine Artefakte durch Fixation oder bioptische Eingriffe darstellen.
    Notes: Summary A biopsy was taken from the vastus lateralis of a man of 49 years with slowly progressive myopathy largely confined to the quadriceps muscles. Both atrophic fibres and ring fibres were numerous. The atrophic fibres showed increase in glycogen and mitochondria and loss of myofilaments as the lesser changes, with fragmentation and gross disorganisation of myofilaments in the more severely affected fibres. Folds of basement membrane projected from their surfaces. Phagocytes occurred in a few degenerate fibres and in basement membrane tubes. All the ring fibres examined had an intact longitudinal core with a closely applied encircling band of myofibrils. Severe changes of the type found in the atrophic fibres were not seen in the ring fibres. Degenerative changes were confined to the circumferential myofibrils, which presented loss of myofilaments of varying degree and aggregations of glycogen and mitochondria. We believe that ring fibres are genuine structures and are not artefacts produced either by fixation or by the biopsy procedure.
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  • 14
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 16 (1970), S. 271-284 
    ISSN: 1432-0533
    Keywords: Medulloblastoma ; Electron Microscopy ; Arachnoid Sarcoma ; Lymphocyte-Like Cells ; Dark Cells ; Histogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung 9 Medulloblastome wurden elektronenmikroskopisch untersucht. Sie zeigten eine relativ einheitliche histologische und cytologische Struktur. Die Tumorzellen haben eine wechselnde Form, wenig Organellen und in der Regel zahlreiche cytoplasmatische Fortsätze. In Gewebspartikeln, die nach der vorherigen lichtmikroskopischen Untersuchung aus dem Tumorzentrum stammten, wurden keine Zellen mit glialer oder neuronaler Differenzierung beobachtet. Nur in den am Tumorrand gelegenen Infiltrationszonen, wo die Tumorgrenze nicht mehr sicher zu bestimmen war, fanden sich gliale oder neuronale Zellelemente. — Das Medulloblastom hat die wesentlichen morphologischen Kriterien der kleinzelligen Sarkome und des embryonalen Gewebes. Deren gemeinsames Charakteristicum, daß sie nämlich keine speziellen Differenzierungen besitzen, ist auch eine spezifische Eigenschaft des Medulloblastoms.
    Notes: Summary 9 medulloblastomas were investigated by electron microscopy. They all showed a rather unique histological and cytological structure. The cells were differently shaped, had in general many cytoplasmic processes and only few organells. Special differentiations which would have made tumour elements look like glial or neural cells were not observed when the tissue samples under investigation were carefully selected by light microscopical examination. Glial or neural elements were found only in infiltration zones where no clear distinction between pre-existing cerebellar and tumourous tissues could be made by conventional histological investigation. Medulloblastomas have essentially the same appearance as parvicellular sarcomas or embryonic tissues. Their common characteristic, viz. that they usually show no special differentiation, is also the most specific quality of medulloblastomas.
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  • 15
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 16 (1970), S. 342-352 
    ISSN: 1432-0533
    Keywords: Neuroaxonal Dystrophy, Infantile ; Cortical Biopsy ; Spheroid-Like Axons ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Ein 21/2 Jahre altes arabisches Mädchen (Eltern Cousins 2. Grades) bot seit dem 1. Lebensjahr progressive psychomotorische Retardierung. Eine Hirnrindenbiopsie ergab normale lichtoptische Verhältnisse, während elektronenoptisch reichlich schollenartige Axonauftreibungen gefunden wurden. Ihr Inhalt setzte sich aus vesico-tubulärem Material oder aus dicht gepacktem filamentösen Material zusammen. Synapsen waren zwischen den Sphäroiden und anderen neuronalen Somata sowie Dendriten nachweisbar. In den Mitochondrien und Sphäroiden fanden sich kristalline Strukturen. Es wird vermutet, daß die “neuroaxonale Dystrophie” durch Rindenbiopsie diagnostiziert werden kann.
    Notes: Summary A 21/2 year old girl who, since the age of 1 year presented, a progressive psychomotor retardation. A cortical biopsy appeared normal by light microscopy, but by electron microscopy an abundance of dilated spheroid-like axons were found. They contained either vesiculo-tubular material or densly packed filamentous material. Synapses were demonstrated between the spheroids and other neuronal bodies or dendrites. Crystalline like material was observed within mitochondria and the spheroids. It is suggested that Neuroaxonal dystrophy may be diagnosed by cortical brain biopsy.
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  • 16
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    Pflügers Archiv 317 (1970), S. 187-197 
    ISSN: 1432-2013
    Keywords: Muscle Spindles ; Intrafusal Muscle Fibres ; Electron Microscopy ; Rabbit ; Muskelspindel ; Intrafusalen Muskelfasern ; Elektronenmikroskopie ; Kaninchen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. The ultrastructure of muscle spindles in deep lumbrical muscles of adult rabbit has been investigated. Contrary to findings obtained by previous authors at the light microscope, indicating morphologic uniformity of intrafusal fibre type in rabbit spindles, two populations of intrafusal muscle fibres have been detected. 2. The first type of fibres is made by myofibrils which have a thick Z line and lack a distinct M line. These fibres are also characterized by the apparent fusion of fibrillar fields due to the paucity of the sarcoplasm, which contains very little glycogen. The mitochondria are scattered and of small size. The sarcoplasmic reticulum is poorly developed and the triads are quite rare. These fibres resemble the nuclear bag fibres of cat muscle spindles. 3. The second type of fibres is made by myofibrils which have a thin Z line and a prominent M line. There is a great separation of the fibrillar fields as a result of abundant sarcoplasm which contains large accumulation of glycogen and ribosomes. The mitochondria are densely distributed and of large size. The sarcoplasmic reticulum is well developed and the triads are rather numerous. These fibres resemble the nuclear chain fibres of cat muscle spindles. 4. The demonstration of two types of intrafusal muscle fibres in rabbit spindles may account for the duality of physiological responses obtained from these receptor organs in this animal species.
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  • 17
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    Cell & tissue research 109 (1970), S. 297-305 
    ISSN: 1432-0878
    Keywords: Bladder ; Bufo marinus ; Transport ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The appearance of the mucosal cell layer of the isolated urinary bladder of the toadBufo marinus, has been examined using stereoscopic and conventional transmission electron microscopy. Three cell types can be identified in surface view, these are granular cells, mitochondriarich cells and goblet cells. Cell boundaries between granular cells are clearly defined by membranous folds along their margins. Although no changes are seen in the stereoscopic electron micrographs when the granular cells are made permeable to water by vasopressin, the changes observed on transmission electron micrographs include swelling of cell bodies and nuclei, filling of intercellular channels with water, and the appearance beneath the mucosal cell membrane surface of electron dense granules. Differences between the appearance of the bladder mucosal cells by the two methods of electron microscopical examination are due largely to water loss when the tissue is freeze dried prior to stereoscopic examination.
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  • 18
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    Biopolymers 9 (1970), S. 811-824 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The root-mean-square end-to-end distance has been calculated for a model allowing free rotation about glycoside bonds for the general case of polysaccharides having a disaccharide repeating unit. Numerical estimates are given for several naturally occurring structures based on an idealized pyranose unit in the C1 chair conformation. Extrapolation procedures which make use of the intrinsic viscosity [η] in good solvents to obtain unperturbed dimensions do not represent, data for hyaluronic acid very well, especially at low molecular weights. However, order-of-magnitude estimates suggest that this polymer behaves similarly to other polysaccharides, and probably has stiffer local structure than typical non-ionic synthetic polymers. A double logarithmic plot of the product of [η] and M̄w, the weight-average molecular weight, against the degree of polymerization in the range for M̄w of 104 to 2 × 104 permits a straight-line fit of available data for all the glycosaminoglycans, including heparin and the chondroitin sulfates, as well as sodium carboxymethyl cellulose. This result suggests similarity of short-chain hydrodynamic behavior of these polymers.
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  • 19
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    Biopolymers 9 (1970), S. 875-875 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 20
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    Biopolymers 9 (1970) 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 21
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    Biopolymers 9 (1970), S. 865-874 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A common approximation for deriving solutions to the Lamm equation is to neglect diffusion. This paper presents a singular perturbation technique that allows one to estimate the band spreading due to nonzero diffusion coefficient. We illustrate the general mathematical technique by its application to sedimentation when pressure effects are important. Comparison of the approximate solution with accurate numerical solutions shows that the relative errors are of the order of 1% both for concentration and concentration gradient for parameters of chemical interest.
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  • 22
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    Biopolymers 9 (1970), S. 891-896 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Glycogen acquires a negative charge in both alkaline and acidic solutions and can move in an electrical field, its mobility being related to the degree of alkalinity or acidity. There is a slight increase in relative viscosity at both ends of the pH spectrum. These effects and the changes in nuclear magnetic resonance as a function of pH are interpreted.
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  • 23
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The viscosity of bovine liver glutamate dehydrogenase solutions was studied at 10 and 20° C in 0.2.M sodium phosphate buffer at pH 7, in the concentration range 0.1-8 mg/ml. A method for the study of the viscosity of very dilute solutions of associating enzymes is described. It was found that the reduced specific viscosity ηsp/c of glutamate dehydrogenase continuously increases with increasing enzyme concentration, from about 4 ml/g at the lowest concentrations to about 16 ml/g at 8 mg/ml. In the presence of 10-3M GTP and 10-3M NADH the viscosity increase is much smaller and the results can be extrapolated to zero enzyme concentration to yield an intrinsic viscosity [η] = 3.2. The values of ηsp/c in phosphate buffer alone apparently extrapolate to the same value of [η], or to a value close to it. We also observe that, in the presence of toluene ηsp/c increases very much more with enzyme concentration: ηsp/c already equals 16 ml/g at a concentration of 0.75 mg/ml. These observations are in good agreement with the hypothesis that the active oligomer of glutamate dehydrogenase (MW = 312,000) associates with increasing enzyme concentration to form linear rodlike polymers of indefinite length. This association is strongly diminished by the addition of 10-3M GTP, 10-3M NADH. Toluene, on the other hand, promotes reversible association to linear polymers of very high molecular weight. The transverse and axial rotary frictional coefficients of macroscopic bodies, similar to a physical model for the structure of glutamate dehydrogenase recently advanced, were determined. Assuming that the viscosity of the model is equal to that of an ellipsoid of rotation with identical frictional coefficients, we calculate [η] = 3.26 ml/g according to Kuhn and 3.20 ml/g according to Simha, for the glutamate dehydrogenase oligomer, in good agreement with the result derived from the study of enzyme solutions.
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  • 24
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    Biopolymers 9 (1970), S. 911-922 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Molecular monolaycrs of poly(β-benzyl L-aspartate) spread at. an air-water interface have been studied. The results obtained both by direct observations on the monlayer and from examination of collapsed films with polarized infrared spectroscopy and electron diffraction are consistent with the presence of right handed α-helices in the mono-layer when the molecular weight is high. When 1% (v/v) isopropanol is present in the subphase the right-handed helix prevails, provided that the monolayer is first spread on water. Monolayers of low molecular weight polymer appear to form the crossed-β structure. Orientated collapsed films of high molecular weight polymer can be converted to the left-handed α-helical and to the ω-conformation, and the mechanisms are discussed. The surface chemistry of this polymer is compared with that of related polymers and a consistent pattern of behavior emerges.
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  • 25
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    Biopolymers 9 (1970), S. 1017-1028 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Low-angle light scattering results reported previously demonstrated that measurements on high molecular weight native DNA must be made at angles below 30° in order to obtain correct molecular weights. Earlier light-scattering data obtained on denaturated DNA at angles above 30° showed no change in molecular weight upon denaturation, even though other techniques clearly showed that strand separation occurred. This paper reports low-angle measurements on solutions of calf thymus and T7 DNA denatured under acidic conditions. The results demonstrate that a halving of molecular weight consistent with strand separation is detected by light scattering only when low-angle data are used to obtain correct molecular weights for native material. As expected from theoretical considerations, the scattering from denatured DNA is a linear function of sin2(θ/2), where θ is the angle of observation. This result shows that anticipated experimental artifacts have no significant effect on the low-angle measurements and demonstrates that the curvature in the scattering envelope observed for native DNA below 30° is an inherent property of the native molecule.
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  • 26
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics for the cis-trans isomerization of long-chain poly-L-proline has been studied as a function of pressure, temperature, and solvent composition in the acetic acid + n-propanol solvent system. Our complete kinetic curves were fitted by Monte Carlo techniques, and rate constants for nucleation, growth, and termination were estimated. It was found that for the formation of a cis-helix, high pressure, low temperature, and increased acetic acid content of the solvent, lowered the rate of nucleation relative to growth. The inverse seems to be t rue for the formation of a trans-helix. Molecular models suggest that this behavior of the kinetic constants can be due to the exposure of peptide units to solvent in the transition state for trans nucleation, and the burying of peptide units in the transition state for cis nucleation. It is further suggested from our analysis of complete kinetic curves that at least one of the assumptions usually made in the analysis of relaxation kinetics is invalid for poly-L-proline.
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  • 27
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    Biopolymers 9 (1970), S. 1039-1047 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Solutions of amylose in ethylenediamine yield a crystalline film complex upon evaporation of solvent. The x-ray analysis indicates the presence of a tetragonal-shaped cell with a symmetry approximating that of space group P212121. The amylose sixfold helix has a diameter of 13.3 Å and a translation period of 8.0Å. Chemical and physical analyses support a complexing ratio of one ethylenediamine molecule to every two glucose units. The structure is nearly identical to any amylose-dimethyl sulfoxide complex previously examined. The square mode of packing arrangement appears to result from complexation between amylose chains. Such complexing indicates a much greater degree of amylose interaction than is observed in amylose complex structures having a hexagonal close-packing arrangement.
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  • 28
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    Biopolymers 9 (1970), S. 1049-1058 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: pH titration measurements of poly- S-carboxymethyl-L-cysteine were undertaken in the aqueous Nacl solution in relation to the β form-random coil transition. The titration curves show a marked molecular weight dependence because of the shortened chain length of materials. Comparison of the optical rotatory dispersion parameter a0 with the titration curve reveals that the titration curve apparently reflects a β structure-random coil transition. The β form of this polymer is assumed to be an intramolecular β form, rather than a β structure stabilized by an intermolecular hydrogen bond, at least in the polymer concentration range considered here. The standard free energy change per amino acid residue for the transition from un-ionized random coil to un-ionized β form is estimated to be about -750 cal/mole residue in the range of 0.005-0.2M NaCl concentration.
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  • 29
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    Biopolymers 9 (1970), S. 1059-1077 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The circular dichroism (CD) spectra of the four usual deoxymononucleosides, all sixteen deoxydinucleotides, and a number of trinucleotides have been measured. The dimer spectra are quite different from the sum of the spectra of their constituent monomers. This indicates the presence of base-stacked conformations analogous to those found for ribonucleoside diphosphates. The CD spectra of several deoxytrinucleotide diphosphates and single-strand f 1 DNA can be calculated fairly well by using a semi-empirical nearest-neighbor approach. There is little or no effect of terminal phosphate or of salt concentration on the optical properties of most deoxy oligomers. The possibility of simultaneous analysis of mixtures of deoxypurine or deoxypyrimidine sequence isomers has been examined. This seems to be a viable approach for the analysis of purine runs but cannot promise much success for pyrimidine runs.
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  • 30
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    Biopolymers 9 (1970), S. 1079-1103 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The circular dichroism spectra of all 16 ribodinudeoside phosphates containing the bases adenine, uracil, cytosine, and guanine have been measured at room temperature and neutral pH. These results are compared with the circular dichroism spectra of the corresponding deoxy compounds. From the optical properties it is clear that the geometry of the base-stacked conformation of ribo compounds must differ substantially from that of deoxy compounds. Because of this, it is not possible to draw firm conclusions about the relative extent of stacking in most ribo and deoxy compounds. The optical rotatory dispersion of about a dozen deoxy and ribodinucleoside phosphates has been studied as a function of temperature. These results confirmed the conclusions drawn earlier from measurements at a single temperature. Several dinucleoside phosphates containing a 2′ → 5′ phosphodiester bond have also been examined. These compounds have a substantial degree of base stacking at room temperature. The geometry of the stacked conformation is different from that of either the normal ribo dimer or the deoxy dimer. The role of the 2′-hydroxyl group in stabilizing base stacked geometries has been examined by studies on C-2′-O-methyl-pC. This compound has optical properties almost identical to those of CpC. This suggests that the effect of the 2′ hydroxyl is felt indirectly through its perturbation of the geometry of the sugar ring rather than directly by hydrogen bonding. It is not possible at present to identify precise conformational differences among deoxy-, ribo-and 2′ → 5′ ribodinucleoside phosphates.
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  • 31
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    Biopolymers 9 (1970), S. 1119-1124 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Ill.
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  • 32
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    Biopolymers 9 (1970), S. 1349-1360 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The influence of single-strand breaks on the kinetics of the relaxation of DNA in a solution of low ionic strength has been investigated by a temperature jump method. The relaxation of DNA after a jump of 0.7 °C in the melting region has been monitored by measuring the extinction at 260 nm. For essentially monodisperse T4 DNA (M = 130 × 106) two distinct relaxation times have been observed, that depend markedly on the initial extent of denaturation 1 - θ. The larger relaxation time decreases from 450 sec to about 300 sec, the smaller one from 55 see to 30 when 1 - θ increases from 0.03 to about 0.8. The dependence of these relaxation times on the average number of single-strand breaks per molecule (p) appears to be very small up to p = 100. However, the relative contribution of the slow process decreases sharply when p increases from 0.6 to 30 and remains nearly constant for larger p. The observations are discussed in the light recent theories of the kinetics of denaturation.
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  • 33
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    Biopolymers 9 (1970), S. 1361-1372 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Measurements have been made of the intensity of light scattered from aqueous solutions of calf thymus DNA with and without the application of electric fields. For fields approaching 150 V/cm and frequencies below 2.5 KHz, changes (ΔI) of up to 10% in the residual scattered intensity were observed. In agreement with previous dielectric and electric birefringence measurements, a low frequency dispersion of ΔI was observed, from which a rotary diffusion constant (D) of 1200 s-1 was determined. Interpreting the electric field data in terms of the classical dipolar orientation theory led to values of 2.4 × 10-25 cm (7.4 × 10-14 esu) and 4.3 × 10-25 cm (13 × 10-14 esu) for the permanent dipole moment and the anisotropy of the electric polarisabilities respectively. Furthermore the permanent dipole moment was along the major molecular axis and the particles orientated in the field as rigid entities. The zero field data indicated a molecular shape which was not rodlike but corresponded to the Kratky-Porod “stiffness” parameter of x = 24 for the wormlike coil model. Although curved, the molecules appeared to orientate in low-intensity electric fields as rigid, but not rodlike molecules. The implications of this on recent discrepancies in D determined by two or more dynamic relaxation methods is briefly discussed.
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  • 34
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    Biopolymers 9 (1970), S. 1391-1402 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The buoyant density of T-4 DNA was determined by equilibrium sedimentation in a density gradient, of mixed solutions of cesium and magnesium chlorides and bromides. The preferential hydration was calculated from these data, allowing appropriately for the exchange equilibrium of DNA with Cs+ and Mg++ ions. The charge and intrinsic solvation of the counterions were found to have no appreciable effect on the hydration of the DNA, the extent of solvation depending only on the thermodynamic, activity of the water. Various reasonable hypotheses are discussed to account for these results.
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  • 35
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    Biopolymers 9 (1970), S. 1373-1389 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction of 27 SMS2 RNA with formaldehyde normally results in an unfolded, 13.4 S form. At acidic pH, however, and under the proper ionic conditions, a compact component sedimenting at 36-40 S was obtained. The molecular weight of this species corresponds to a dinner. The formaldehyde concentration was not critical, and approximately the same number of base pairs had been opened in the compact and in the unfolded form. Presumably dimers, which had been specifically formed under defined conditions, were stabilized by formaldehyde-induced crosslinks. Similar dimers were formed by 16 S and by 23 S ribosomal RNA, but not by tRNA.
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  • 36
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    Chemie in unserer Zeit 4 (1970), S. 26-32 
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 37
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    Keywords: Chemistry ; Chemistry
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  • 38
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    Chemie in unserer Zeit 4 (1970), S. 44-50 
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 39
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    Chemie in unserer Zeit 4 (1970), S. 51-54 
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 40
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    Chemie in unserer Zeit 4 (1970), S. 37-43 
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 6 Ill.
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  • 41
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    Chemie in unserer Zeit 4 (1970), S. 35-36 
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 42
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    Chemie in unserer Zeit 4 (1970), S. 55-60 
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 43
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    Chemie in unserer Zeit 4 (1970), S. 61-62 
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 44
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    Chemie in unserer Zeit 4 (1970), S. 63-63 
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 45
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  • 46
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 47
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    Biopolymers 9 (1970), S. 445-457 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The change in apparent molal volume φ of DNA on thermal denaturation in carbonate buffer at pH 11.0 has been determined by the dilatometric method. It was found that φ increases sigmoidally during the helix-coil transition. Several methods, including a colorimetric technique that closely simulates the conditions used in the dilatometric experiments, were employed to estimate the protons lost by the DNA during the transition. These measurements indicated that the extent of the proton loss depends on the counterion present, increasing in the order Li+ 〈 Na+ 〈 K+ 〈 Cs+. The major part of the volume changes observed during the denaturation is due to the volume changes expected to accompany the transfer of protons from the bases guanine and thym ne to carbonate ions. As has been previously reported for the denaturation of DNA at neutral pH, the volume change directly due to the change in shape of the polymer molecules is so small as to be experimentally undetectable.
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  • 48
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    Biopolymers 9 (1970), S. 569-588 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The coupling of theoretical optical calculations with experimental data provides a check of the validity of the theory or provides conformational information. The theory was validated by studies in which the approximate conformation was located independently. These studies have shown that a theory restricted to the two lowest energy transitions for each chromophore gives qualitative agreement with experiment. On the other hand, for some of the proline derivatives, the theoretical treatment allows detailed conformational assignments. Both successes and failures in correlating theory with experiment are discussed. The results presented provide a basis for assessing the prospects for relating protein and polypeptide optical activity to their conformations.
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  • 49
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ethidium bromide inhibits the formation of ultraviolet-induced pyrimidine dimers in DNA. The efficiency of dimer inhibition increases with increasing energy of the exciting photons. The efficiency of energy transfer from the DNA singlet to the dye singlet, as monitored by sensitized fluorescence, is independent of wavelength. The efficiency of singlet-singlet transfer agrees with that for dimer inhibition at photon energies corresponding to excitation of the lowest singlet state of DNA. Our results support a model in which dimers are formed both directly from the singlet state and also from the triplet state, with triplets arising from higher vibrational levels of the singlet.
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  • 50
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    Biopolymers 9 (1970), S. 689-696 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The intercalation model of DNA-hydrocarbon binding appears reasonable, but rests on indirect evidence only. To test the model, a size criterion for binding has been proposed. The size criterion is based on the assumption that hydrophobic forces play a major role in the binding of hydrocarbons to DNA. It states that hydrocarbons which are small enough to intercalate into DNA and be well protected from contact with the medium, will be found to bind to DNA; those that are too large will not. We report results on the binding of fourteen polycyclic aromatic hydrocarbons to DNA. Predictions based on the size criterion were found to be valid in all cases tested.
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  • 51
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    Biopolymers 9 (1970), S. 697-715 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The dialysis data of Huang and Ts'o for the cooperative binding of adensine to polyuridylic acid are analyzed here using a grand-partition function Ising model method similar to that originally employed for polyelectrolytes by Rice and Nagasawa. An appropriate modification permitting the treatment of the sliding degeneracy of the two polyuridylic acid strands is also included. In addition to the previously estimated stacking energy of about -6 kcal/mole one also obtains the free energy change F̄ for the transfer of a single adenosine molecule from a fixed site in solution to a fixed site on the polyuridylic acid. This binding energy falls in the range F̄ = -140 to +620 cal/mole, indicating that binding in the 1:2 (purine: pyrimidine) complex is either very weak or repulsive. The absence of any comparable cooperative stacking of adenosines in solution at the same concentration together with the likely repulsive character of the binding implies that the stacking energy must contain a significant contribution from other processes than simple stacking of adenosines. A generalization of the theory to treat multicomponent binding and longer-range interactions is effected, and the form applicable to simultaneous binding of both adenosine and guanosine by polyuridylic acid is presented.
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  • 52
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    Biopolymers 9 (1970), S. 739-744 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The present communication describes a new way of studying helix-random coil transformations of polypeptide, poly-(γ-benzyl L-glutamate), in benzene-trifluoracetic acid (TFA) and chloroform-TFA systems. The difference between the PMR chemical shift of TFA with and without the polypeptide, measured as Δ, may be used to follow the conformational transition. This technique is particularly useful for concentrated solutions, where the PMR peaks of the polymer are so broad that no valuable information may be derived. As the TFA content increases in the system (at constant polymer concentration), Δ decreases normally whether the polymer is helical or random. However, Δ changes in a different way in the helix-random coil transition region, and actually increases with increasing TFA content. This peculiar behavior is explained in terms of the solvation of the helix and random coil structures.
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  • 53
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    Biopolymers 9 (1970), S. 745-748 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
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  • 54
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    Biopolymers 9 (1970), S. 717-738 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new procedure for evaluating u and σ characterizing σ-helix-forming polypeptides in solution was derived from Nagai's theory for the helix-coil transition of such polymers. Here u is the activity for helix formation from random coil, and σ is the helix initiation parameter. The necessary data are the helical content fN at fixed solvent and temperature as a function of N, where N is the degree of polymerization of the polypeptide sample. Such data were obtained from ORD measurements on a number of fractionated samples of poly-N5-(3-hydroxypropyl)-L-glutamine (PHPG) in mixtures of water and methanol covering the complete range of composition and at various termperatures (5-40°C). When analyzed in terms of the proposed procedure, they yielded values of σ which were in the range (3.2 ± 0.6) × 10-4, substantially independent of solvent composition and temperature. These values were much larger than those obtained recently for σ of poly(β-benzyl-L-aspartate) in m-cresol and in a mixture of chloroform and DCA. The data for [η] and s0 (limiting sedimentation coefficient) as functions of molecular weight indicated that the molecular shape of PHPG in pure methanol is essentially rodlike, whereas that in pure water is not entirely randomly coiled but rather may be regarded as an interrupted helix. These indications were consistent with the results from ORD measurements. When plotted against the corresponding values of fN, the values of [η] and [s0] for PHPG in mixtures of water and methanol of various compositions and temperatures formed smooth composite curves, and we attributed these phenomena to the fact that σ of PHPG was nearly constant under these solvent conditions. Here [s0] stands for a reduced limiting sedimentation coefficient which is equal to the inverse friction factor of the solute molecule.
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  • 55
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    Biopolymers 9 (1970) 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 56
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    Biopolymers 9 (1970), S. 765-782 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The interaction of purine with DNA, tRNA, poly A, poly C, and poly A. poly U complex was investigated. In the presence of purine, the nucleic acids in coil form (such as denatured DNA, poly A and poly C in neutral solutions, or tRNA) have lower optical rotations. In addition, hydrodynamic studies indicate that in purine solutions the denatured DNA has a higher viscosity and a decreased sedimentation coefficient. These findings indicate that through interaction with purine, the bases along the poly-nucleotide chain are unstacked and are separated farther from each other, resulting in increased assymmetry (and possibly volume) of the whole polymer. Thus, the de-naturation effect of purine reported previously can be explained by this preferential interaction of purine with the bases of nucleic acids in coil form through a hydrophobic-costacking mechanism. Results from studies on optical rotation and helix-coil transition show that the interaction of purine is greater with poly A than with poly C. The influence of temperature, Mg++ concentration, ionic strength, and purine concentration on the effect of purine on nucleic acid conformation has also been investigated. In all these situations the unraveling of nucleic acid conformation occurs at much lower temperatures (20-40°C lower) in the presence of purine (0.2-0.6M).
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  • 57
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The characteristic ratio of unperturbed cellulose chain was computed as a function of the angle τ at, the bridge oxygen atom and the degree of polymerization. Very high values of the order of 40 or more, depending on the angle at the bridge oxygen atom, have been obtained for this ratio, indicating that cellulose chains are highly extended. The average dimensions of cellulose chains are found to be sensitive even for small changes in the angle at the bridge oxygen, and these chains attain the character of a random coil in very high molecular weight range (degree of polymerization greater than 2000). The large differences in the unperturbed dimensions of cellulosic chains observed in different solvents have been attributed to the possible small changes in the angle τ caused by specific solvent, interactions.
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  • 58
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The conformational properties of block copolymers of poly-L-leucine in water have been examined. The degree of polymerization of the poly-L-leucine block was 11 and 21, respectively, for samples prepared by the Merrifield procedure, and 56 for a sample prepared by the polymerization of leucine N-carboxyanhydride. The optical rotatory dispersion parameter b0 was used to obtain the helix content θh at various temperatures. Application of the Lifson-Roig theory gave the following parameters for the transition of a residue from a coil to a helical state: v = 0.05-0.011, ΔH = +100 cal/mole, ΔS = +0.70-1.00 e. u. These parameters, as well as those for other polyamino acids, are accounted for by hydrophobic bonds involving the nonpolar side chains in the helical and randomly coiled forms. From the data for poly-L-alanine and theoretical values of the thermodynamic parameters for hydrophobic bond formation, the parameters for formation of a polyglycine helix are computed. By separating the contributions of the backbone, it is possible to obtain a set of thermodynamic parameters for the side-chain contributions of a number of polyamino acids. Increased size of the nonpolar side chain (with a larger contribution from hydrophobic bonding) makes a larger contribution to the stability of the α-helix which is reflected, among other ways, in a higher helix content at given temperature.
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  • 59
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The polymerization of DL-β-phenylalanine N-carboxyanhydride (NCA) initiated by poly(N-benzylglycine)diethylamide (DEA) and poly(N-methyl-DL-alanine)DEA has been investigated. As previously reported, polysarcosine DEA, poly-N-ethylglycine DEA, and poly-N-n-propylglycine DEA showed marked accelerations in the polymerization of DL-β-phenylalanine NCA as compared with the polymerization initiated by low molecular weight, amines having similar base strength. However, this phenomenon (the chain effect) was not observed with the two polymer catalysts studied in the present investigation With poly-N-methyl-DL-alanine DEA, adsorption of DL-β-phenylalanine NCA onto the polymer chain takes place, though not so effectively as with other polypeptides, so the absence of chain effect was ascribed to a reduced flexibility of the polymer chain. With poly(N-benzylglycine)DEA, the reactivity of terminal base group was found to be much lower than that of other polymer catalysts. However, the absence of the chain effect would be attributed to the rigidity of polymer chain of poly-N-benzylglycine DEA due to the bulkiness of the N-benzyl group.
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  • 60
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    Biopolymers 9 (1970), S. 799-810 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Molecular weights by osmometry (M̄n), light scattering (M̄w), and sedimentation-diffusion (MsD) were determined for selected fractions and unfractionated samples of hyaluronic acid in the molecular weight range 3 × 104-1.7 × 106. For the determination of MsD from the sedimentation coefficient s, a calibration procedure based on the data of Laurent, Ryan, and Pietruszkiewicz gave the following relations in 0.2M NaCl: log (s-1)0 = 14.681 - 0.413 log MsD and log D0 = -3.828 - 0.568 log MsD, where subscript, zero refers to zero concentration and D is the diffusion coefficient. The average Mandelkern-Flory parameter β in 0.2M NaCl is 3.0 × 106. Data for the intrinsic viscosity [η] may be fitted for M 〉 105 by [η] = K′Ma, where K′, a are in 0.2M NaCl, 0.0228, 0.816; in 0.5M NaCl, 0.0318, 0.777; in 0.1 M HCl, 0.0279, 0.763, respectively. Below M = 105, [η] appears to fall below the values calculated, possibly due to non-Gaussian behavior of short chains. The second virial coefficient A2 in 0.5M NaCl approaches the ideal Donnan value, decreasing slightly with increasing molecular weight. The friction parameter P is about 20% smaller than that of uncharged polymers of similar dimensions. The flexible coiling nature of this polymer is confirmed.
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  • 61
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    Biopolymers 9 (1970), S. 843-864 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The formation of a slowly sedimenting form of 23-S ribosomal RNA from E. coli has been investigated by analytical ultracentrifugation and thermal denaturation in aqueous solution and in formamide. Evidence is presented that the slow form of 23-S arises as a result of nucleate damage to the RNA in the 50-S ribosome. The 30-S ribosome (and 16-S RNA), is unaffected. The slow form of 23-S RNA cannot be demonstrated under conditions of complete denaturation in formamide, but only by partial denaturation in aqueous solution of low ionic strength (〈 0.01M Na). Apparent maintenance of the integrity of 23-S RNA in formamide after nuclease treatment suggests that this may not be a simple linear molecule. An alternative model is suggested containing a circular element in the structure.
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  • 62
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    Biopolymers 9 (1970), S. 825-842 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Uniform LiDNA fiber specimens of nearly 20 m length have been prepared with a wet-spinning method developed by the author. Samples immersed in the spinning bath (80% ethyl alcohol containing 0.4M LiCl) have been subjected to mechanochemical study involving stretching, relaxation, and contraction measurements. A special technique was developed to transfer the sample from the Teflon-coated cylinder used in spinning to the sample column of the mechanochemical apparatus without stretching or removing the sample from the spinning bath. Force-strain curves of samples consisting of two fiber bundles showed an initial region of low slope followed by a region of high slope and a second region of low slope up to rupture. Some thicker specimens showed an aging effect which abolished the initial low-slope region and was interpreted as indicative of crystallization. Force-strain curves of two-bundle samples showed a strong influence of temperature with a complete loss of tensile strength of the LiDNA fibers in the spinning bath at about 55°C. Furthermore, samples at zero strain exhibited a contractile force when subjected to temperatures above about 40°C; the contractile process was pronounced with samples kept above 48°C. On contraction these samples obtained a zero-force length 20-30% of the original. These data are taken as evidence for a helix-to-coil transition occurring in the DNA, the low melting temperature being caused by the chemical influence of the ambient aqueous alcohol-LiCl bath.
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  • 63
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    Biopolymers 9 (1970), S. 1029-1038 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The molecular weight of native DNA is shown to decrease by at least a factor of two on denaturation by heat or alkali. This result is obtained only if low-angle (〈30°) light-scattering measurements are used. High-angle measurements (〉30°) do not reveal a decrease in molecular weight on denaturation due to the incorrect value for native DNA. The dn/dc value for both native and denatured DNA is 0.166 ml/g ± 0.003 ml/g. Methods are described for the clarification of native and denatured DNA solutions for light scattering by the use of membrane filters.
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  • 64
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    Biopolymers 9 (1970), S. 991-1000 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Electric dichroism studies on poly(γ-benxyl L-glutamate) show that the addition of small amounts (up to 5%) of trifluoroacetic acid causes complete disappearance of dichroism in contrast to the electric birefringence, which drops to an observable plateau at 20% of its initial value. This loss of dichroism cannot be explained simply by a decrease in the effective dipole moment of the benzyl ester side chains, and the nature of this interaction is explored by nuclear magnetic resonance and infrared spectral studies. Theories of the helix-coil transition which require an initial protonation of the helix backbone to form a more flexible rod consisting of helical segments interrupted by regions of random coil are shown to be inadequate to describe the changes in poly(γ-benzyl L-glutamate) effected by small amounts of trifluoroacetic acid. Rather, trifluoroacetic acid in small amounts interacts with the ester carbonyl oxygen in the side chain, either by hydrogen bonding or protonation, before there is evidence of any effect on the backbone or of loss of helix content.
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  • 65
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    Biopolymers 9 (1970), S. 1229-1237 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Raman spectra of poly-L-lysine hydrochloride and poly-∊-carbobenzoxy-L-lysine in the solid state have been obtained and are consistent with the presence of an α-helical structure. The Raman spectrum of poly-L-lysine in aqueous solution suggests the presence of random coil structures.
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  • 66
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 67
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    Biopolymers 9 (1970) 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 68
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The nonbonded interaction energy of disaccharides, mannobiose and galactobiose and polysaccharides mannan and galactan have been computed as a function of dihedral angles (φ,ψ). The conformation (40°, -20°) has been preferred for the mannan chain from nonbonded interaction energy considerations. The O5…O3′ type of intramolecular hydrogen bond has been found to be possible in the above conformation. Comparison of the allowed region of mannan with those of cellulose and xylan indicates that the monomer unit, in mannan chain has slightly higher freedom of rotation than that of cellulose and less than that of xylan. As in cellulose and mannan, the freedom of rotation of the monomer units in β-1,4′ galactan is highly restricted. Unlike mannan (which prefers an extended conformation) the β-1,4′ galactan prefers a helical conformation similar to amylose. Just as in amylose the O2…O3′ type hydrogen bond between contiguous residues is also possible in β-1,4′ galactan.
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  • 69
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 23 Ill.
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  • 70
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    Biopolymers 9 (1970), S. 1475-1502 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The predictions of the presently accepted molecular exciton model for the optical activity of helical polypeptides are in reasonable agreement with experimental spectra in the accessible wavelength range. However, crucial verification requires the detect of a significant negative rotatory hand just below the accessible range. A computer-oriented method is utilized to obtain information concerning the inaccessible range. Optical rotatory dispersion computed by evaluation of the Kronig-Kramers integral transform from the experimentally determined circular dichroism of several helical homopolypeptides in solution are compared with the experimentally determined optical rotatory dispersion. Computed and experimental curves are congruent within an uncertainty approaching that of the experimental technique, whatever the polypeptide sample lot, side chains, and solvent. It is shown that t his agreement is not a computational or experimental artifact. These results can be interpreted in two ways: (1) that the predicted band does not exist, and (2) that the perturbation of the predicted band is being negated by other inaccessible bands in the vacuum ultraviolet. Arguments are presented to show that the first of these two possibilities is more probable.
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  • 71
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    Biopolymers 9 (1970), S. 1511-1530 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The potential problem is formulated for rodlike macroions and reduced to a single dimensionless equation with appropriate boundary conditions. A method of solution based on piecewise linearization of the potential equation is detailed and compared with two other approaches. It is suggested that the present method yields improved estimates of macroion charges. Some numerical results are included, and the relation between electrophoretic charge and macroion charge is considered.
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  • 72
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
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  • 73
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  • 74
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    Chemie in unserer Zeit 4 (1970), S. 65-65 
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 75
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    Chemie in unserer Zeit 4 (1970), S. 66-68 
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    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 76
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    Chemie in unserer Zeit 4 (1970), S. 69-80 
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    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    Chemie in unserer Zeit 4 (1970), S. 95-98 
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    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 78
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    Chemie in unserer Zeit 4 (1970), S. 129-132 
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    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 79
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    Chemie in unserer Zeit 4 (1970), S. 152-158 
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 4 Ill.
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  • 80
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    Chemie in unserer Zeit 4 (1970), S. 159-162 
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 4 Ill.
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    Chemie in unserer Zeit 4 (1970) 
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    Keywords: Chemistry ; Chemistry
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  • 82
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    Chemie in unserer Zeit 4 (1970), S. 163-164 
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 83
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    Chemie in unserer Zeit 4 (1970), S. 177-179 
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 4 Ill.
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  • 84
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    Chemie in unserer Zeit 4 (1970), S. 165-176 
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 14 Ill.
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  • 85
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    Chemie in unserer Zeit 4 (1970), S. 180-187 
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 86
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    Chemie in unserer Zeit 4 (1970), S. 188-193 
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 6 Ill.
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  • 87
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    Chemie in unserer Zeit 4 (1970), S. 194-194 
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 88
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    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 89
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    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 90
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 91
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    Chemie in unserer Zeit 4 (1970), S. 197-198 
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 92
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 93
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    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 104-111 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation and Properties of FluoromethyldialkylaminesFluoromethyldialkylamines (3a-f) are prepared from N,N-acetals (aminals) by cleavage with carboxylic acid fluorides or l-fluoro-2,4-dinitrobenzene. They are low-boiling liquids and are characterized by a covalent carbon-halogen bond. Their reactivity is similar to that of the analogous carbimonium chlorides, bromides and iodides.
    Notes: Fluormethyl-dialkyl-amine (3a-f) werden durch Spaltung von Aminalen mit Carbonsäurefluoriden oder l-Fluor-2.4-dinitro-benzol gewonnen. Sie sind niedrigsiedende, durch eine kovalente Kohlenstoff-Halogen-Bindung charakterisierte Flüssigkeiten und zeigen ähnliche Reaktionsfähigkeit wie die analogen Carbimoniumchloride, -bromide oder -jodide.
    Additional Material: 3 Ill.
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  • 94
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    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 133-146 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Heterosubstituted Fulvenes, IV In the 5-Membered Ring Unsubstituted 6,6-DiaminofulvenesAlkylation of tetrasubstituted thioureas with methyl iodide leads to S-methyl isothiuronium iodides 3, which have been transformed to 6,6-diaminofulvenes 1 by condensation with cyclopentadienyl sodium. Some compounds of type 1 are also obtainable from the reaction between cyclopentadiene and chloroformamidinium chlorides 4 in the presence of triethylamine. I.r., u.v., and n.m.r. spectra of 1 and 3 are discussed.
    Notes: Tetrasubstituierte Thioharnstoffe lassen sich mit Methyljodid in die S-Methyl-isothiuroniumjodide 3 überführen, die ihrerseits mit Cyclopentadienylnatrium die 6.6-Diamino-fulvene 1 bilden. Einzelne Vertreter von 1 sind auch aus Cyclopentadien und Chlorformamidinium-chloriden 4 in Gegenwart von Triäthylamin zugänglich. Die IR-, UV- und NMR-Spektren von 1 und 3 werden diskutiert.
    Additional Material: 3 Tab.
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  • 95
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    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 183-192 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: VinylsulfonylmethylidsThe preparation of dimethylsulfonio-(vinylsulfonylphenylsulfonylmethanide) (5), triphenyl-phosphonio-(vinylsulfonylphenylsulfonylmethanide) (6) and triphenylphosphonio-(vinyl-sulfonylbenzoylmethanide) (8) is described. The u. v. spectra of 5 and 6 are similar to the u.v. spectrum of the bis(phenylsulfonyl)methane anion (9). Because of the interaction of the SO2-groups with the ylide carbanions, the SO2-stretching frequencies compared to those of vinylsulfonylphenylsulfonylmethane (4) are shifted 20 -30/cm to lower wave numbers. This interaction causes a higher electron density in the vinyl groups of the ylids compared to 4, as shown by n. m. r. measurements. The mass spectra of 5, 6 and 8 are discussed.
    Notes: Die Synthese von Dimethylsulfonio-[vinylsulfonyl-phenylsulfonyl-methanid] (5), Triphenyl-phosphonio-[vinylsulfonyl-phenylsulfonyl-methanid] (6)undTriphenylphosphonio-[vinyl-sulfonyl-benzoyl-methanid] (8) wird beschrieben. Die Elektronenspektren von 5 und 6 sind mit dem UV-Spektrum des Bis-phenylsulfonyl-methan-Anions (9) vergleichbar. Durch Wechselwirkung der SO2Gruppen mit den Ylidcarbanionen werden die SO2-Valenzschwingungsfrequenzen im Vergleich zu Vinylsulfonyl-phenylsulfonyl-methan (4) um 20 - 30/cm zu kleineren Wellenzahlen verschoben. Diese Wechselwirkung bedingt eine höhere Elektronendichte in den Vinylgruppen der Ylide als bei 4, was NMR-spektroskopisch nachweisbar ist. Die Massenspektren von 5, 6 und 8 werden diskutiert.
    Additional Material: 6 Ill.
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  • 96
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    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 173-182 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Cyclopentadienones with Aliphatic Diazo Compounds, 6 Experiments with „Indanocyclone“„Indanocyclone“ 3, prepared from ninhydrin (1) and dibenzylketone (2), reacts with an ethereal diazomethane solution to form an 1 :1-adduct 4a and two isomeric 1 : 2-adducts, presumably 12 and 13. Elimination of N2 from 4a leads to the formation of the cyclopropane 7, the fluorenone 6 and, by way of phenyl migration, the new cyclone 8a; elimination of N2 from 12 and 13 leads to undefined products. 5 is converted via its hydrazone into the diazo compound 10. Ring enlargement of 6 with diazomethane produces the phenanthrene 9.Reaction of diazoethane with 3 gives the instable 1 :1-adduct 4b, which yields the new cyclone 8b by N2-elimination and phenyl migration. 8b also forms an 1 :1-adduct (11?). Phenyl diazomethane adds to 3 giving a rather stable 1 :1-adduct 14, the isomeric 16 and the epoxide 15. Elimination of N2 from 14 yields the fluorenone derivative 17, which upon treatment with excess diazomethane undergoes ring enlargement to form the phenanthrene derivative 18.
    Notes: Das aus Ninhydrin(l)und Dibenzylketon(2) erhältliche, Indanocyclon‘ 3 gibt mit ätherischer Diazomethanlösung ein 1 :1-Addukt 4a und zwei isomere 1 : 2-Addukte, vermutlich 12 und 13. 4a zerfällt unter N2-Abspaltung zum Cyclopropanderivat 7, zum Fluorenonderivat 6 und unter Phenylwanderung zum neuen Cyclon 8a; 12 und 13 geben bei der N2-Abspaltung keine definierten Produkte. Aus 5 wird über sein Hydrazon die Diazoverbindung 10 und mit Diazomethan unter Ringerweiterung das Phenanthrenderivat 9 erhalten.Mit Diazoäthan entsteht aus 3 das instabile I :1-Addukt 4b, das bei der N2-Abspaltung unter Phenylwanderung das Cyclon 8b bildet; dieses gibt erneut ein Diazoathan-Addukt (11?).Mit Phenyldiazomethan liefert 3 ein ziemlich stabiles 1 :1-Addukt 14 und sein Isomeres 16 sowie das Epoxid 15. Bei der N2-Abspaltung entsteht aus 14 das Fluorenonderivat 17, das mit Diazomethan zum Phenanthrenderivat 18 ringerweitert wird.
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  • 97
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    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 222-235 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Orthoamides, X: Reaction of Vinylogous Amide Acetals, Aminalesters and Amide AminalsDerivates of vinylogous orthoformic acid amides react with Grignard compounds to give l,3-bis(dimethylamino)-l-alkenes (4-7), with methylene active compounds to give derivates of N.N-disubstituted 4-amino-l,3-butadienes (17  - 29) and with primary aromatic amines to form vinylogous, N,N,N′-trisubstituted amidines (31-36, 38-40).
    Notes: Vinyloge Orthoameisensäureamid-Derivate geben mit Grignard-Verbindungen 1.3-Bis - dimethylamino-alkene-(l) (4-7), mit methylenaktiven Verbindungen N.N-disubstituierte 4 - Amino-butadien-(l.3)-Derivate (17-29) und mit primären aromatischen Aminen vinyloge N.N.N′-trisubstituierte Amidine (31-36, 38-40).
    Additional Material: 3 Tab.
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  • 98
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    Berichte der deutschen chemischen Gesellschaft 103 (1970) 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 99
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    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 17-22 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Pyrimidines, VIII Synthesis and Properties of Uracil-4-carbaldehyde Hydrazone. The First Inner Orbital Complex of a Pyrimidine with CopperUracil-4-carbaldehyde (1) reacts with stoechiometric amounts of hydrazine to yield the azine 2. Under mild conditions (30 per cent hydrazine, room temperature) the azine is cleaved to uracil-4-carbaldehyde hydrazone (3). This cleavage by hydrazine is typical for the azomethine group in position 4 of the uracil ring. In aqueous or aqueous-alcoholic solution 3 reacts readily with aliphatic, aromatic and heterocyclic aldehydes to form mixed azines in good yield. With copper(II)-acetate 3 yields in aqueous solution a new type of symmetrical inner orbital complex in which the ratio of pyrimidine to copper is 2 :1. The crystalline and insoluble paramagnetic complex 13 presumably has a planar structure. Substitution of the amino group, even with a methyl group, prevents complex formation. 13 is decomposed by mineral acids to the respective copper salt and azine 2. In analogy to 1 2-thiouracil-4-carb-aldehyde forms the corresponding hydrazone 12.
    Notes: Uracil-carbaldehyd-(4) (1) liefert mit stöchiometrischer Menge Hydrazin das symmetrische Azin 2, welches unter milden Bedingungen (30proz. Hydrazin, Raumtemperatur) zum Uracil-carbaldehyd-(4)-hydrazon (3) gespalten wird. Die schonende Hydrazinolyse ist spezifisch für die Azomethingruppe in 4-Stellung des Uracilrings. 3 liefert in wäßriger bzw. Wäßrig-alkoholischer Lösung mit aliphatischen, aromatischen und heterocyclischen Aldehyden in guter Ausbeute gemischte Azine. Mit Kupfer(II)-acetat bildet 3 einen neuartigen symmetrischen Innerkomplex der Art Pyrimidin : Kupfer = 2:1. Analog zu Uracil-carb-aldehyd-(4) (1) erhält man aus 2-Thio-uracil-carbaldehyd-(4) mit Hydrazin das entsprechende Hydrazon 12.
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  • 100
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    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 46-49 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Crystal Structure of l,2,3,4,4a,9a-hexahydro-4a,9-propanocarbazolium HydrobromideThe crystal structure of the title compound has been determined by X-ray structure analysis. From these results a twist angle of 64.5° of the orbital of the nitrogen is derived.
    Notes: Auf röntgenographischem Weg wurde die Kristallstruktur der Titel-Verbindung bestimmt. Aus den so erhaltenen Ergebnissen resultiert ein Verdrillungswinkel des Orbitals am Stickstoff von ϕpH = 64.5°.
    Additional Material: 3 Ill.
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