Distribution of proteins in the extracellular space of muscles and the possible role of mucopolysaccharides

Zusammenfassung Muskeln wurden in Ringerlösung mit 20% Hämoglobin oder Myoglobin equilibriert. In gefärbten Schnitten erscheint der extrazelluläre Raum im Elektronenmikroskop dunkel, aber lange Filamente, Mukofilamente genannt, bleiben ungefärbt. Diese haben einen Durchmesser von 500 oder 300 å, je nachdem ob das erste oder zweite der Proteine verwendet wurde. Diese Struktur unterscheidet sich deutlich von Kollagenfibrillen durch ihre diffuse Oberfläche, ihre Dicke, ihre Färbung und andere Eigenschaften und besteht wahrscheinlich aus Mukopolysacchariden.     

A possible role of acid mucopolysaccharides in the urine concentrating process

Résumé Par l'adsorption de plus d'eau que de corps dissous, les acides mucopolysaccharides (MPS-s) de la medulla interne du rein peuvent participer à l'élaboration d'urine concentrée. Ce nouveau mécanisme hypothétique laisse supposer que le MPS est le produit d'une synthèse cellulaire et qu'il prend l'eau d'adsorption au moment de la secrétion. Ensuite, le MPS quitte le rein par les voies veineuses et lymphatiques et enfin se détruit dans un autre organe.

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Participant of the USPHS Career Award Program.     

Evolution of the extracellular space in immature nervous tissue

Resumen En el cerebelo de rata recién nacida existen espacios extracelulares mayores que 1000 Å los cuales progresivamente se reducen hasta que en la tercera semana, como en el adulto, las celulas y fibras se hallan separadas por endiduras de 150–200 Å. Estas observaciones indican que el reducido espacio usualmente hallado en el adulto no es un artificio tecnico como ha sido sugerido por algunos autores.     

Distribution of inulin-carboxy-C14 in heart and skeletal muscle with respect to in vivo and in vitro extracellular space determinations

Zusammenfassung Gleichmässige Indikatorverteilung im Gewebe ist Ausdruck für Konzentrationsausgleich zwischen Blutstrom bzw. Inkubationsmedium und Extrazellulärraum. Es wurde ein zentraler Block aus einem Gewebsstück herausgeschnitten und die Konzentration von Inulin-carboxyl-C¹⁴ darin mit der im peripheren oberflächlichen Gewebe verglichen. Im Myokard des linken Ventrikels und im Soleusmuskel fand sich in vivo eine gleichmässige Verteilung, in vitro hingegen nicht; selbst bei einer Inkubationsdauer von 5 h in einem als optimal anzusehenden Milieu. Damit ist die Methode, wahre Extrazellulärräume in vitro zu messen, fragwürdig. Hingegen hat sich die Echtheit von in-vivo-Bestimmungen bestätigt.

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This investigation was supported in part by U.S. Public Health Service Research Grant No. HE-09791 from the National Heart Institute and General Research Support Grant No. SO1-FR-05525 from the Division of Research Facilities and Resources, and in part by a grant from the John A. Hartford Foundation.     

Periostin and its interacting proteins in the construction of extracellular architectures

Periostin is a matricellular protein that is composed of a multi-domain structure with an amino-terminal EMI domain, a tandem repeat of four FAS 1 domains, and a carboxyl-terminal domain. These distinct domains have been demonstrated to bind to many proteins including extracellular matrix proteins (Collagen type I and V, fibronectin, tenascin, and laminin), matricellular proteins (CCN3 and βig-h3), and enzymes that catalyze covalent crosslinking between extracellular matrix proteins (lysyl oxidase and BMP-1). Adjacent binding sites on periostin have been suggested to put the interacting proteins in close proximity, promoting intermolecular interactions between each protein, and leading to their assembly into extracellular architectures. These extracellular architectures determine the mechanochemical properties of connective tissues, in which periostin plays an important role in physiological homeostasis and disease progression. In this review, we introduce the proteins that interact with periostin, and discuss how the multi-domain structure of periostin functions as a scaffold for the assembly of interacting proteins, and how it underlies construction of highly sophisticated extracellular architectures.     

The determination of extracellular space using hemoglobin

Summary The ECS of guinea-pig atria and frog sartorii can be determined using hemoglobin. For guinea-pig atria an ECS of (32.2±2.6)% wet wt for frog sartorii an ECS of (12.4±1.0)% wet wt can be measured.This work was supported by the Deutsche Forschungsgemeinschaft SFB 114 Bionach.     

Divergence of the in vitro and in vivo extracellular space measurements in heart muscle

Zusammenfassung Extrazellulärraumindikatorverteilung ist in vivo und in vitro unterschiedlich, trotz ähnlicher Tendenz. Das Myokard verändert sich während der in-vitro-Inkubation. Deshalb erscheint es unmöglich, in vitro normale beziehungsweise in vivo herrschende Extrazellulärräume zu messen.     

Insulin and its possible role in the artificial hibernation

Riassunto Gli autori hanno studiato la possibilità di facilitare l'ipotermia degli omeotermi mediante l'insulina. Hanno osservato che gli animali ibernati in ipoglicemia insulinica non presentano mai chok post-perfrigerazione, che il risveglio è sempre molto rapido e che l'ibernazione ha un decorso molto più soddisfacente dei controlli non trattati con insulina.     

Distribution of inulin space in the rabbit thoracic aorta

Zusammenfassung Die ganze Länge und Dicke des extrazellulären Raumes der thorakalen Kaninchenaorta wurde gemessen. Der Raum ist unverändert die ganze Länge des Blutgefässes hindurch und entspricht 0,59 ml/g 0,39 ml/g für die Adventitia und die Media. In jeder dieser Tunicae ist der Raum durch ihre ganze Dicke gleichmässig verteilt.

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Supported by grants from The American Medical Association Education and Research Foundation, U.S. Public Health Service (HE-08359) and the Los Angeles County Heart Association (408 IG).     

Clusterin facilitates in vivo clearance of extracellular misfolded proteins

The extracellular deposition of misfolded proteins is a characteristic of many debilitating age-related disorders. However, little is known about the specific mechanisms that act to suppress this process in vivo. Clusterin (CLU) is an extracellular chaperone that forms stable and soluble complexes with misfolded client proteins. Here we explore the fate of complexes formed between CLU and misfolded proteins both in vitro and in a living organism. We show that proteins injected into rats are cleared more rapidly from circulation when complexed with CLU as a result of their more efficient localization to the liver and that this clearance is delayed by pre-injection with the scavenger receptor inhibitor fucoidan. The CLU–client complexes were found to bind preferentially, in a fucoidan-inhibitable manner, to human peripheral blood monocytes and isolated rat hepatocytes and in the latter cell type were internalized and targeted to lysosomes for degradation. The data suggest, therefore, that CLU plays a key role in an extracellular proteostasis system that recognizes, keeps soluble, and then rapidly mediates the disposal of misfolded proteins.     

Spirally arranged muscles associated with tracheoles in tsetse fly flight muscles; their possible involvement in sound production

Summary A set of muscle fibres have been found associated with certain tracheoles in the flight muscles of the tsetse fly. It is proposed that those muscles may be involved in sound production in the fly.I am grateful to the Ministry of Overseas Development for a grant in support of this work and to Professor L.H. Finlayson for his advice and criticism.     

The possible role of glutamine in some cells of the immune system and the possible consequence for the whole animal

Glutamine is important for the function of lymphocytes and macrophages. A role for the high rate of glutamine utilisation by these cells is presented. Since muscle syntheses, stores and releases glutamine, this tissue may play a role in the immune response. Since the number of immune cells utilising glutamine may be large, the demand for glutamine from muscle, especially during trauma sepsis or burns, may be very high. A speculative suggestion is put forward that this requirement for glutamine from muscle may play a role in cachexia under some of these conditions.     

A possible role of guanine-deaminase inhibitor

Zusammenfassung Diskussion über die Frage der Ätiologic der Xanthinurie.